140 results on '"Convit, A"'
Search Results
2. The Hyperhydration Potential of Sodium Bicarbonate and Sodium Citrate
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Jason C. Siegler, Amelia J. Carr, William T. Jardine, Lilia Convit, Rebecca Cross, Dale Chapman, Louise M. Burke, and Megan Ross
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Adult ,Male ,Nutrition and Dietetics ,Sodium ,Water ,Medicine (miscellaneous) ,General Medicine ,Sodium Citrate ,Bicarbonates ,Young Adult ,Sodium Bicarbonate ,Sweetening Agents ,Humans ,Female ,Orthopedics and Sports Medicine - Abstract
Buffering agents have not been comprehensively profiled in terms of their capacity to influence water retention prior to exercise. The purpose of this investigation was to profile the fluid retention characteristics of sodium bicarbonate (BIC) and sodium citrate (CIT) to determine the efficacy of these buffering mediums as hyperhydrating agents. Nineteen volunteers (13 males and six females; age = 28.3 ± 4.9 years) completed three trials (randomized and cross-over design). For each trial, a baseline measurement of body mass, capillary blood, and urine was collected prior to ingestion of their respective condition (control condition [CON] = 25 ml/kg artificially sweetened water; BIC condition = CON + 7.5 g/L of sodium in the form of BIC; CIT condition = CON + 7.5 g/L of sodium in the form of CIT). The fluid loads were consumed in four equal aliquots (0, 20, 40 and 60 min; fluid intake was 1.972 ± 361 ml [CON]; 1.977 ± 360 ml [BIC]; 1.953 ± 352 ml [CIT]). Samples were recorded at 20 (body mass and urine) and 60 min (blood) intervals for 180 min. Blood buffering capacity (HCO3−) was elevated (p p p p = .05). There were no increases observed in body mass (p = .9). Under resting conditions, these data suggest BIC and CIT induce a greater plasma hypervolemic response as compared with water alone.
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- 2022
3. Platelet Function Is Associated With Dementia Risk in the Framingham Heart Study
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Jaime Ramos‐Cejudo, Andrew D. Johnson, Alexa Beiser, Sudha Seshadri, Joel Salinas, Jeffrey S. Berger, Nathanael R. Fillmore, Nhan Do, Chunlei Zheng, Zanetta Kovbasyuk, Babak A. Ardekani, Nunzio Pomara, Omonigho M. Bubu, Ankit Parekh, Antonio Convit, Rebecca A. Betensky, Thomas M. Wisniewski, and Ricardo S. Osorio
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Adenosine Diphosphate ,Male ,Platelet Aggregation ,Platelet Function Tests ,Alzheimer Disease ,Risk Factors ,Humans ,Female ,Longitudinal Studies ,Cardiology and Cardiovascular Medicine - Abstract
Background Vascular function is compromised in Alzheimer disease (AD) years before amyloid and tau pathology are detected and a substantial body of work shows abnormal platelet activation states in patients with AD. The aim of our study was to investigate whether platelet function in middle age is independently associated with future risk of AD. Methods and Results We examined associations of baseline platelet function with incident dementia risk in the community‐based FHS (Framingham Heart Study) longitudinal cohorts. The association between platelet function and risk of dementia was evaluated using the cumulative incidence function and inverse probability weighted Cox proportional cause‐specific hazards regression models, with adjustment for demographic and clinical covariates. Platelet aggregation response was measured by light transmission aggregometry. The final study sample included 1847 FHS participants (average age, 53.0 years; 57.5% women). During follow‐up (median, 20.5 years), we observed 154 cases of incident dementia, of which 121 were AD cases. Results from weighted models indicated that platelet aggregation response to adenosine diphosphate 1.0 µmol/L was independently and positively associated with dementia risk, and it was preceded in importance only by age and hypertension. Sensitivity analyses showed associations with the same directionality for participants defined as adenosine diphosphate hyper‐responders, as well as the platelet response to 0.1 µmol/L epinephrine. Conclusions Our study shows individuals free of antiplatelet therapy with a higher platelet response are at higher risk of dementia in late life during a 20‐year follow‐up, reinforcing the role of platelet function in AD risk. This suggests that platelet phenotypes may be associated with the rate of dementia and potentially have prognostic value.
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- 2022
4. Does obesity-associated insulin resistance affect brain structure and function of adolescents differentially by sex?
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Kathy F. Yates, Stephanie London, Radiology Antonio Convit, and Andrea Gabay
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,business.industry ,Neuroscience (miscellaneous) ,Brain Structure and Function ,Brain ,medicine.disease ,Affect (psychology) ,Obesity ,Article ,Psychiatry and Mental health ,Executive Function ,Insulin resistance ,Endocrinology ,Cognition ,Internal medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Female ,Insulin Resistance ,business - Abstract
Metabolic abnormalities affect the adolescent brain. For equivalent abnormalities in metabolism young people exhibit deficits in more cognitive domains than adults. We examine sex differences performance for adolescents with obesity/insulin resistance (IR) and evaluated how sex and IR effected frontal lobe structures and executive functioning. 125 adolescents underwent medical, cognitive, and brain-imaging assessments. Participants were categorized as insulin sensitive (IS) (QUICKI ≧ 0.350) or IR (QUICKI < 0.350). Degree of IR may affect brain and cognition differentially by sex. Females had positive associations between QUICKI and anterior cingulate cortex (ACC) volume, medial orbito-frontal cortex (OFC) thickness, and scores on the Stroop and Digit Symbol Substitution (DSST) tests. Females with IR tended to have thinner insular cortices. No such associations were found in males. In female adolescents, IR may negatively affect brain structure and function. No such effects were found for males. Although needing more development, hormonal effects and inflammation are potential contributors.
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- 2021
5. Toxicity evaluation of ConvitVax breast cancer immunotherapy
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Jeismar M Carballo O, Teresa Gledhill, Yetsenia M De Gouveia, María A Duarte C, Ana Federica Convit, Eglys González-Marcano, Angie García, and Diana Cecilia Gracia Ruiz
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Oncology ,medicine.medical_specialty ,Drug-Related Side Effects and Adverse Reactions ,medicine.medical_treatment ,Science ,Immunology ,Breast Neoplasms ,Article ,Mice ,Immune system ,Therapeutic index ,Breast cancer ,Internal medicine ,Medicine ,Animals ,Humans ,Adverse effect ,Cancer ,Kidney ,Mice, Inbred BALB C ,Multidisciplinary ,business.industry ,Immunotherapy ,medicine.disease ,medicine.anatomical_structure ,Toxicity ,BCG Vaccine ,Female ,business - Abstract
ConvitVax is a personalized vaccine for the treatment of breast cancer, composed of autologous tumor cells, bacillus Calmette-Guérin (BCG) and low concentrations of formalin. Previous pre-clinical studies show that this therapy induces a potent activation of the immune system and achieves an effective response against tumor cells, reducing the size of the tumor and decreasing the percentage of immunosuppressive cells. In the present study, we evaluate the toxicity of ConvitVax in healthy BALB/c mice to determine potential adverse effects related to the vaccine and each of its components. We used standard guidelines for pain, discomfort and distress recognition, continuously evaluated the site of the injection, and completed blood and urine clinical tests. Endpoint necropsy was performed, measuring the weight of organs and processing liver, kidney, thymus and lung for histological examination. Results show that the vaccine in its therapeutic dose, at 3 times its therapeutic concentration, and its individual components did not cause death or behavioral or biological changes, including any abnormalities in whole-body or organ weights, and tissue damage. These results support the safety of ConvitVax with minimal to no side-effects.
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- 2021
6. Cognitive functions among predominantly minority urban adolescents with metabolic syndrome
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Antonio Convit, Kathy F. Yates, Alexander Mangone, Victoria Sweat, and Adriana Joseph
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Male ,Gerontology ,Adolescent ,Urban Population ,Vital signs ,030209 endocrinology & metabolism ,Disease ,Neuropsychological Tests ,Body Mass Index ,Young Adult ,03 medical and health sciences ,Cognition ,0302 clinical medicine ,Diabetes mellitus ,Developmental and Educational Psychology ,medicine ,Humans ,Minority Groups ,Metabolic Syndrome ,Cognitive flexibility ,Reproducibility of Results ,Adolescent Obesity ,medicine.disease ,Obesity ,United States ,Neuropsychology and Physiological Psychology ,Female ,Waist Circumference ,Metabolic syndrome ,Cognition Disorders ,Psychology ,Psychomotor Performance ,030217 neurology & neurosurgery - Abstract
The rise in the rate of adolescent obesity has led to a concurrent rise in the rate of metabolic syndrome (MetS) among young people. In addition to diabetes and cardiovascular disease, MetS has also been linked to cognitive dysfunction. The goal of this study was to assess whether cognitive differences exist between minority urban adolescents carrying excess weight who meet criteria for MetS as compared to their peers without MetS. Two hundred and ninety-six urban adolescents, predominantly Hispanic and carrying excess weight as defined by a BMI above 25 kg/m2, were screened for MetS and divided into MetS and no MetS groups. All participants completed the CNS Vital Signs (CNS-VS) computerized neurocognitive battery that assesses cognitive domains of Memory, Processing Speed, Reaction Time, Executive Function, Complex Attention, and Cognitive Flexibility. The MetS group (29.2%, n = 84) performed significantly lower on 2 of the 7 cognitive domains: Executive Function (EF) and Cognitive Flexibility. ...
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- 2017
7. Effects of aging on slow-wave sleep dynamics and human spatial navigational memory consolidation
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Ricardo S. Osorio, Esther Fischer, Omar Burschtin, Tyler Gumb, Antonio Convit, Indu Ayappa, Andrew W. Varga, Po Lai Yau, Margaret E. Wohlleber, David P. Leibert, David M. Rapoport, Viachaslau Koushyk, Ankit Parekh, Emma L. Ducca, and Akifumi Kishi
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Male ,0301 basic medicine ,Aging ,medicine.medical_specialty ,Adolescent ,media_common.quotation_subject ,Audiology ,Spatial memory ,Article ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Neuroimaging ,Memory ,medicine ,Humans ,Young adult ,Maze Learning ,Prefrontal cortex ,Aged ,media_common ,Slow-wave sleep ,Aged, 80 and over ,Psychomotor learning ,General Neuroscience ,Brain ,Middle Aged ,Magnetic Resonance Imaging ,030104 developmental biology ,Female ,Memory consolidation ,Neurology (clinical) ,Geriatrics and Gerontology ,Sleep ,Psychology ,Neuroscience ,Psychomotor Performance ,030217 neurology & neurosurgery ,Spatial Navigation ,Developmental Biology ,Vigilance (psychology) - Abstract
The consolidation of spatial navigational memory during sleep is supported by electrophysiological and behavioral evidence. The features of sleep that mediate this ability may change with aging, as percentage of slow wave sleep is canonically thought to decrease with age, and slow waves are thought to help orchestrate hippocampal-neocortical dialogue that supports systems level consolidation. In this study, groups of younger and older subjects performed timed trials before and after polysomnographically recorded sleep on a 3D spatial maze navigational task. Although younger subjects performed better than older subjects at baseline, both groups showed similar improvement across pre-sleep trials. However, younger subjects experienced significant improvement in maze performance during sleep that was not observed in older subjects, without differences in morning psychomotor vigilance between groups. Older subjects had sleep quality marked by decreased amount of slow wave sleep and increased fragmentation of slow wave sleep, resulting in decreased slow wave activity. Across all subjects, frontal slow wave activity was positively correlated with both overnight change in maze performance and medial prefrontal cortical volume, illuminating a potential neuroanatomical substrate for slow wave activity changes with aging and underscoring the importance of slow wave activity in sleep-dependent spatial navigational memory consolidation.
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- 2016
8. Analysis of the MIRIAD Data Shows Sex Differences in Hippocampal Atrophy Progression
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Babak A. Ardekani, Antonio Convit, and Alvin H. Bachman
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Male ,0301 basic medicine ,Oncology ,Gerontology ,medicine.medical_specialty ,Hippocampal formation ,Hippocampus ,03 medical and health sciences ,0302 clinical medicine ,Atrophy ,Text mining ,Alzheimer Disease ,Internal medicine ,Image Processing, Computer-Assisted ,medicine ,Humans ,Dementia ,Longitudinal Studies ,business.industry ,General Neuroscience ,Female sex ,General Medicine ,medicine.disease ,Magnetic Resonance Imaging ,Hippocampal atrophy ,Psychiatry and Mental health ,Clinical Psychology ,030104 developmental biology ,Disease Progression ,Female ,Geriatrics and Gerontology ,business ,Psychology ,030217 neurology & neurosurgery - Abstract
BACKGROUND Hippocampus (HC) atrophy is a hallmark of early Alzheimer's disease (AD). Atrophy rates can be measured by high-resolution structural MRI. Longitudinal studies have previously shown sex differences in the progression of functional and cognitive deficits and rates of brain atrophy in early AD dementia. It is important to corroborate these findings on independent datasets. OBJECTIVE To study temporal rates of HC atrophy over a one-year period in probable AD patients and cognitively normal (CN) subjects by longitudinal MRI scans obtained from the Minimal Interval Resonance Imaging in AD (MIRIAD) database. METHODS We used a novel algorithm to compute an index of hippocampal (volumetric) integrity (HI) at baseline and one-year follow-up in 43 mild-moderate probable AD patients and 22 CN subjects in MIRIAD. The diagnostic power of longitudinal HI measurement was assessed using a support vector machines (SVM) classifier. RESULTS The HI was significantly reduced in the AD group (p < 10(-20)). In addition, the annualized percentage rate of reduction in HI was significantly greater in the AD group (p < 10(-13)). Within the AD group, the annual reduction of HI in women was significantly greater than in men (p = 0.008). The accuracy of SVM classification between AD and CN subjects was estimated to be 97% by 10-fold cross-validation. CONCLUSION In the MIRIAD patients with probable AD, the HC atrophies at a significantly faster rate in women as compared to men. Female sex is a risk factor for faster descent into AD. The HI measure has potential for AD diagnosis, as a biomarker of AD progression and a therapeutic target in clinical trials.
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- 2016
9. Obesity, fitness, and brain integrity in adolescence
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Antonio Convit, Po Lai Yau, and Naima Ross
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Male ,Pediatric Obesity ,medicine.medical_specialty ,Adolescent ,media_common.quotation_subject ,Physical fitness ,Prefrontal Cortex ,Brain Structure and Function ,Audiology ,Article ,Developmental psychology ,Young Adult ,Oxygen Consumption ,Insulin resistance ,Task Performance and Analysis ,medicine ,Humans ,General Psychology ,media_common ,Nutrition and Dietetics ,business.industry ,Working memory ,Neuropsychology ,Brain ,VO2 max ,medicine.disease ,Memory, Short-Term ,Physical Fitness ,Exercise Test ,Female ,Orbitofrontal cortex ,Insulin Resistance ,business ,Psychology ,Vigilance (psychology) - Abstract
Objective: We set out to ascertain the relationship between insulin resistance, fitness, and brain structure and function in adolescents. Design and methods: We studied 79 obese and 51 non-obese participants who were recruited from the community, all without type 2 diabetes mellitus. All participants received medical, endocrine, neuropsychological, and MRI evaluations as well as a 6-minute walk test that was used to estimate fitness (maximal oxygen consumption). Results: Obese adolescents had significantly thinner orbitofrontal cortices and performed significantly worse on Visual Working Memory tasks and the Digit Vigilance task. Insulin sensitivity and maximal oxygen consumption (VO2 max) were both highly correlated with central obesity and orbitofrontal cortical thickness, although insulin sensitivity was the stronger predictor for orbitofrontal cortical thickness. We also found that VO2 max was the only significant physiological variable related to visual working memory. Conclusions: This is the first study to report positive associations between insulin resistance, VO2 max, and frontal lobe brain integrity in adolescents. Given the importance of brain health for learning and school performance, we conclude that schools should also emphasize physical fitness in order to maintain structural and functional brain integrity and facilitate academic achievement.
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- 2015
10. Lifestyle and vascular risk effects on MRI-based biomarkers of Alzheimer’s disease: a cross-sectional study of middle-aged adults from the broader New York City area
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Richard S. Isaacson, Mony J. de Leon, Antonio Convit, Christine A. Ganzer, Pauline McHugh, Randolph E Andrews, Ricardo S. Osorio, Joanna Sterling, Crystal Quinn, Dawn C. Matthews, Lisa Mosconi, and Michelle Walters
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Gerontology ,Adult ,Male ,lifestyle ,Cross-sectional study ,Disease ,Overweight ,Diet, Mediterranean ,03 medical and health sciences ,0302 clinical medicine ,Insulin resistance ,Cognition ,Imaging, Three-Dimensional ,Alzheimer Disease ,Risk Factors ,Medicine ,Humans ,030212 general & internal medicine ,Effects of sleep deprivation on cognitive performance ,Life Style ,Temporal cortex ,brain Imaging ,business.industry ,Research ,Brain ,alzheimer’s disease ,General Medicine ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Cross-Sectional Studies ,Neurology ,Posterior cingulate ,Linear Models ,brain aging ,Female ,New York City ,vascular risk ,medicine.symptom ,Atrophy ,business ,030217 neurology & neurosurgery ,Biomarkers - Abstract
ObjectiveTo investigate the effects of lifestyle and vascular-related risk factors for Alzheimer’s disease (AD) on in vivo MRI-based brain atrophy in asymptomatic young to middle-aged adults.DesignCross-sectional, observational.SettingBroader New York City area. Two research centres affiliated with the Alzheimer’s disease Core Center at New York University School of Medicine.ParticipantsWe studied 116 cognitively normal healthy research participants aged 30–60 years, who completed a three-dimensional T1-weighted volumetric MRI and had lifestyle (diet, physical activity and intellectual enrichment), vascular risk (overweight, hypertension, insulin resistance, elevated cholesterol and homocysteine) and cognition (memory, executive function, language) data. Estimates of cortical thickness for entorhinal (EC), posterior cingulate, orbitofrontal, inferior and middle temporal cortex were obtained by use of automated segmentation tools. We applied confirmatory factor analysis and structural equation modelling to evaluate the associations between lifestyle, vascular risk, brain and cognition.ResultsAdherence to a Mediterranean-style diet (MeDi) and insulin sensitivity were both positively associated with MRI-based cortical thickness (diet: βs≥0.26, insulin sensitivity βs≥0.58, P≤0.008). After accounting for vascular risk, EC in turn explained variance in memory (P≤0.001). None of the other lifestyle and vascular risk variables were associated with brain thickness. In addition, the path associations between intellectual enrichment and better cognition were significant (βs≥0.25 P≤0.001), as were those between overweight and lower cognition (βs≥-0.22, P≤0.01).ConclusionsIn cognitively normal middle-aged adults, MeDi and insulin sensitivity explained cortical thickness in key brain regions for AD, and EC thickness predicted memory performance in turn. Intellectual activity and overweight were associated with cognitive performance through different pathways. Our findings support further investigation of lifestyle and vascular risk factor modification against brain ageing and AD. More studies with larger samples are needed to replicate these research findings in more diverse, community-based settings.
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- 2018
11. Outcomes of The BODY Project: A Program to Halt Obesity and Its Medical Consequences in High School Students
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Victoria Sweat, Carole Siegel, Arthur H. Fierman, Alexander Mangone, Jean-Marie Bruzzese, Eugene M. Laska, and Antonio Convit
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Blood Glucose ,Male ,Pediatric Obesity ,medicine.medical_specialty ,Teachable moment ,Health (social science) ,Adolescent ,Health Behavior ,Blood Pressure ,Disease ,Overweight ,Body Mass Index ,Risk Factors ,Diabetes mellitus ,medicine ,Humans ,Insulin ,Health Education ,Life Style ,business.industry ,Public health ,Public Health, Environmental and Occupational Health ,medicine.disease ,Obesity ,Cholesterol ,Blood pressure ,Physical therapy ,Female ,medicine.symptom ,business ,Body mass index - Abstract
Adolescent obesity continues to be a major public health issue with a third of American adolescents being overweight or obese. Excess weight is associated with cardiovascular risk factors and pre-diabetes. High school students identified as carrying excess weight [body mass index (BMI) ≥25 kg/m2, or BMI percentile ≥85 %] were invited to participate in The BODY Project, an intervention that included a medical evaluation and a personalized medical report of the results of that evaluation sent to the parent/guardian at home. The medical evaluation and report was repeated 12 months later. The reports also contained advice on how the individual student could modify their lifestyle to improve the specific medical parameters showing abnormalities. Outcomes were change in BMI, blood pressure, high-density lipoprotein (HDL), low-density lipoprotein (LDL), fasting glucose, and fasting insulin. Students participating in The BODY Project intervention demonstrated modest, yet significant, reductions in BMI (p < 0.001) 1 year later, and also had significant improvements in systolic blood pressure (p < 0.001) and cholesterol profile (HDL p = 0.002; LDL p < 0.001) at follow-up. The BODY Project, by means of a minimal educational program anchored on the principle of teachable moments around the students’ increased perception of their own risk for disease from the medical abnormalities uncovered, demonstrates evidence of potential effectiveness in addressing adolescent obesity.
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- 2015
12. Asian Adolescents with Excess Weight are at Higher Risk for Insulin Resistance than Non-Asian Peers
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Ahmed, Elsamadony, Kathy F, Yates, Victoria, Sweat, Po Lai, Yau, Alex, Mangone, Adriana, Joseph, Arthur, Fierman, and Antonio, Convit
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Adult ,Male ,Metabolic Syndrome ,Adolescent ,Asian ,Body Weight ,Adolescents ,Article ,Young Adult ,Asian People ,Risk Factors ,Humans ,Female ,Obesity ,Insulin Resistance - Abstract
Objective Evaluate whether Asian-American adolescents have higher metabolic risk from excess weight than non-Asians. Methods 733 students, 14- to 19-years old, completed a school-based health screening. The 427 Asian and 306 non-Asian students were overall equivalent on age, sex, and family income. Height, weight, waist circumference, percent body fat, and blood pressure were measured. Fasting bloods measured triglycerides, high- and low-density lipoproteins, glucose, and insulin levels. Asian and non-Asians in lean or overweight/obese groups were contrasted on the 5 factors that make up the Metabolic Syndrome. Results Asian adolescents carrying excess weight had significantly higher insulin resistance (IR), triglyceride levels, and waist to height ratios (W/H), despite a significantly lower overall body mass index (BMI) than corresponding non-Asian. Similarly, Asians had a stronger relationship between W/H and the degree of IR than non-Asian counterparts; 35% and 18% of the variance were explained (R2=0.35, R2=0.18) respectively, resulting in a significant W/H by racial group interaction (Fchange(1,236) = 11.56, p
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- 2017
13. Obese Adolescents Show Reduced Cognitive Processing Speed Compared with Healthy Weight Peers
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Renee Migliaccio, Antonio Convit, Kathy F. Yates, and Victoria Sweat
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Male ,Percentile ,Pediatrics ,medicine.medical_specialty ,Pediatric Obesity ,Adolescent ,Endocrinology, Diabetes and Metabolism ,030209 endocrinology & metabolism ,Corpus callosum ,Childhood obesity ,Body Mass Index ,Corpus Callosum ,03 medical and health sciences ,Executive Function ,Young Adult ,0302 clinical medicine ,Cognition ,Medicine ,Humans ,Metabolic Syndrome ,Nutrition and Dietetics ,business.industry ,Brain ,Original Articles ,medicine.disease ,Obesity ,Magnetic Resonance Imaging ,Cognitive test ,Frontal Lobe ,Frontal lobe ,Pediatrics, Perinatology and Child Health ,Female ,Metabolic syndrome ,Insulin Resistance ,Waist Circumference ,business ,Neurocognitive ,030217 neurology & neurosurgery - Abstract
Childhood obesity and obesity-associated diabetes and metabolic syndrome (MetS) continue to rise. Obesity has been linked to structural and functional brain abnormalities, particularly in the frontal lobe.One hundred sixty-two adolescents (aged 19.53 ± 1.53 years) underwent medical, neurocognitive, and brain magnetic resonance imaging assessments. Participants were either healthy weight (BMI25.0 kg/mGroups differed on four measures of processing speed contained in four different cognitive tests, but not on executive function. A confirmatory factor analysis verified that the significant processing speed variables loaded on the same factor. We also found differences between the weight groups on the area of the anterior portion of the CC, but not the overall CC. Only the Controlled Oral Word Association Test (COWAT) was significantly correlated with the area of the anterior portion of the CC. In the obese group, 32.4% met criteria for MetS. No differences were found between obese participants with or without MetS and none of the MetS factors contributed consistently to cognitive performance.Obese adolescents show slower cognitive processing speed while maintaining equivalent performance on executive functioning compared with their healthy weight peers. The group differences in the anterior portion of the CC, responsible for frontal lobe interhemispheric communication, may in part explain our processing speed findings. Future studies should include a longitudinal design and diffusion tensor imaging to examine the integrity of white matter.
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- 2017
14. Intermediate cutaneous leishmaniasis caused byLeishmania (Viannia) braziliensissuccessfully treated with fluconazole
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Emilia Mia Sordillo, A. E. Paniz-Mondolfi, Hirotomo Kato, Convit J, Olga Zerpa, K. Daly, H. De Lima, and O. Reyes-Jaimes
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Drug ,medicine.medical_specialty ,Antifungal Agents ,media_common.quotation_subject ,Leishmaniasis, Cutaneous ,Context (language use) ,Dermatology ,Disease ,Biology ,Leishmania braziliensis ,Cutaneous leishmaniasis ,Leishmania (Viannia) braziliensis ,medicine ,Humans ,Child ,Fluconazole ,media_common ,medicine.disease ,biology.organism_classification ,Treatment Outcome ,Immunology ,Female ,After treatment ,medicine.drug - Abstract
American cutaneous leishmaniasis is an endemic anthropozoonosis that exhibits a broad spectrum of clinical presentations. Intermediate/borderline disseminated cutaneous leishmaniasis is a distinct clinical condition that comprises cutaneous disease of a chronic nature, usually occurring as multiple lesions with or without mucosal involvement. The disease is usually caused by parasites of the subgenus Viannia, frequently occurs in context of an underlying disease, and is often resistant to standard antileishmanial therapy. We report a case that was refractory to standard therapy and other second-line drugs, but resolved after treatment with fluconazole, and review the use of fluconazole as a second-line drug in children.
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- 2014
15. Preliminary Evidence of Cognitive and Brain Abnormalities in Uncomplicated Adolescent Obesity
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Yau, Po Lai, Kang, Esther H., Javier, David C., and Convit, Antonio
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Male ,Metabolic Syndrome ,Pediatric Obesity ,Adolescent ,Intelligence ,Brain ,Pilot Projects ,cortical thickness ,Neuropsychological Tests ,diffusion tensor imaging ,Magnetic Resonance Imaging ,Article ,Executive Function ,Young Adult ,Cognition ,Memory ,insulin resistance ,Humans ,adolescence ,Attention ,Female ,Obesity ,cognitive performance - Abstract
Objective We ascertain whether pediatric obesity without clinically-significant insulin resistance (IR) impacts brain structure and function. Design and Methods Thirty obese and 30 matched lean adolescents, all without clinically-significant IR or a diagnosis of metabolic syndrome (MetS), received comprehensive endocrine, neuropsychological, and MRI evaluations. Results Relative to lean adolescents, obese non-IR adolescents had significantly lower academic achievement (i.e. arithmetic and spelling) and tended to score lower on working memory, attention, psychomotor efficiency and mental flexibility. In line with our prior work on adolescent MetS, memory was unaffected in uncomplicated obesity. We also uncovered reductions in the thickness of the orbitofrontal and anterior cingulate cortices as well as reductions of microstructural integrity in major white matter tracts without gross volume changes. Conclusions We document, for the first time, that adolescents with uncomplicated obesity already have subtle brain alterations and lower performance in selective cognitive domains. When interpreting these preliminary data in the context of our prior reports of similar, but more extensive brain findings in obese adolescents with MetS and T2DM, we conclude that “uncomplicated” obesity may also result in subtle brain alterations, suggesting a possible dose effect with more severe metabolic dysregulation giving rise to greater abnormalities.
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- 2014
16. Retinal Vessel Abnormalities as a Possible Biomarker of Brain Volume Loss in Obese Adolescents
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Tirsi, Aziz, Duong, Michelle, Tsui, Wai, Lee, Carol, and Convit, Antonio
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Male ,obesity ,retina ,Pediatric Obesity ,Adolescent ,hippocampus ,Body Weight ,Brain ,Retinal Vessels ,Blood Pressure ,Organ Size ,Magnetic Resonance Imaging ,Article ,Body Mass Index ,Young Adult ,Case-Control Studies ,Humans ,Female ,Insulin Resistance ,brain atrophy - Abstract
Endothelial dysfunction in childhood obesity may precede cerebrovascular damage and cognitive impairment in adulthood. A noninvasive proxy of microvascular health is required to identify the risk for microvascular damage in obese children.The associations of hippocampal volumes and global cerebral atrophy were assessed with retinal vessel caliber in 40 normal BMI controls and 62 obese age-matched nondiabetic adolescents and the contribution of inflammation, obesity, and insulin resistance to retinal vessel caliber was evaluated.Compared to controls, obese adolescents had smaller retinal arterioles (8.3% decrease, P0.05) and wider venules (5.4% increase, P0.01). Larger retinal arteriole diameters were associated with less global cerebral atrophy (B = -0.24 [95% confidence interval, CI: -0.48, -0.002]) and larger hippocampal volumes (B = 0.01 [95% CI: 0, 0.02]). Venule diameters (B = 84.2 [95% CI: 30.3, 138.1]) were predicted by inflammation (fibrinogen). Arteriolar diameters were predicted by insulin resistance, indicated by logHOMA (homeostatic model assessment, HOMA) values (B = -17.03 [95% CI: -28.25, -5.81)] and body mass index (BMI) (B = -.67 [95% CI: -1.09, -0.24)]. All analyses were adjusted for mean arterial pressure, sleep apnea, and vessel diameter.Measures of brain health, BMI, and insulin resistance are associated with retinal vessel caliber. If confirmed in larger studies, retinal arteriolar caliber may serve as a possible noninvasive proxy for brain atrophy in obese adolescents, and the identification of elevated risk for cerebral microvascular disease in adulthood.
- Published
- 2013
17. Impact of Blood Sample Collection and Processing Methods on Glucose Levels in Community Outreach Studies
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Cuong Nguyen, Antonio Convit, Mark S. Lifshitz, Michael Turchiano, and Arthur H. Fierman
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Blood Glucose ,Male ,Pathology ,medicine.medical_specialty ,Article Subject ,Adolescent ,Health, Toxicology and Mutagenesis ,Centrifugation ,chemistry.chemical_compound ,Sodium fluoride ,Humans ,Medicine ,Collection methods ,Blood Specimen Collection ,Glucose degradation ,Chromatography ,business.industry ,lcsh:Public aspects of medicine ,Public Health, Environmental and Occupational Health ,lcsh:RA1-1270 ,Cariostatic Agents ,Community-Institutional Relations ,Processing methods ,Blood draw ,chemistry ,Sodium Fluoride ,Female ,Sample collection ,business ,Glycolysis ,Working environment ,Research Article - Abstract
Glucose obtained from unprocessed blood samples can decrease by 5%–7% per hour due to glycolysis. This study compared the impact of glucose degradation on measured glucose values by examining two different collection methods. For the first method, blood samples were collected in tubes containing sodium fluoride (NaF), a glycolysis inhibitor. For the second method, blood samples were collected in tubes containing a clot activator and serum gel separator and were centrifuged to separate the serum and plasma 20 minutes after sample collection. The samples used in the two methods were collected during the same blood draw and were assayed by the clinical laboratory 2–4 hours after the samples were obtained. A total of 256 pairs of samples were analyzed. The average glucose reading for the centrifuged tubes was significantly higher than the NaF tubes by0.196±0.159 mmol/L (P<0.01) or 4.2%. This study demonstrates the important role collection methods play in accurately assessing glucose levels of blood samples collected in the field, where working environment may be suboptimal. Therefore, blood samples collected in the field should be promptly centrifuged before being transported to clinical labs to ensure accurate glucose level measurements.
- Published
- 2013
18. Association of Obesity-Mediated Insulin Resistance and Hypothalamic Volumes: Possible Sex Differences
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Antonio Convit, Jenny Ha, Aziz Tirsi, and Jessica I. Cohen
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Article Subject ,Clinical Biochemistry ,Hypothalamus ,030209 endocrinology & metabolism ,03 medical and health sciences ,Sex Factors ,0302 clinical medicine ,Insulin resistance ,Statistical significance ,Internal medicine ,Nerve Growth Factor ,Genetics ,Humans ,Medicine ,Obesity ,Molecular Biology ,Brain-derived neurotrophic factor ,lcsh:R5-920 ,biology ,business.industry ,Brain-Derived Neurotrophic Factor ,Biochemistry (medical) ,C-reactive protein ,Case-control study ,Organ Size ,General Medicine ,medicine.disease ,C-Reactive Protein ,Endocrinology ,nervous system ,Case-Control Studies ,biology.protein ,Female ,Insulin Resistance ,lcsh:Medicine (General) ,business ,Body mass index ,030217 neurology & neurosurgery ,Research Article - Abstract
The hypothalamus is important in hunger and metabolism. Although a lot is known about the basic role of the human hypothalamus, less is known about how thein vivovolume is affected in obesity, particularly among adolescents. Based on pediatric body mass index percentiles, 95 participants were assigned to lean or obese groups. All subjects had medical evaluations, including fasting blood tests, to assess insulin sensitivity and circulating CRP and neurotrophins (NGF and BDNF) and an MRI of the brain. Hypothalamic volumes were measured by a segmentation method combining manual and automated steps. Overall, obese participants had descriptively smaller hypothalamic volumes, although this difference did not reach statistical significance; however, among obese participants, females had significantly smaller hypothalamic volumes than their male counterparts. There was a significant interaction between insulin resistance and sex on hypothalamus volume; obese females with significant insulin resistance have smaller hypothalamic volumes than obese males. Obese adolescents had higher circulating CRP and neurotrophin levels. Furthermore, among obese females, BDNF concentrations were inversely associated with hypothalamus volumes (r=−0.48). Given this negative association between BDNF and hypothalamus volumes among obese insulin-resistant females, elevated neurotrophin levels may suggest an attempt at protective compensation.
- Published
- 2013
19. Insulin resistance among obese middle-aged is associated with decreased cerebrovascular reactivity
- Author
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Po Lai Yau, Antonio Convit, Ricardo S. Osorio, Henry Rusinek, Olivia Frosch, and Pippa Storey
- Subjects
Adult ,Male ,medicine.medical_specialty ,medicine.medical_treatment ,030209 endocrinology & metabolism ,Overweight ,Article ,Body Mass Index ,Hypercapnia ,03 medical and health sciences ,0302 clinical medicine ,Insulin resistance ,Diabetes mellitus ,Internal medicine ,Medicine ,Humans ,Obesity ,Cognitive decline ,Cerebral Cortex ,business.industry ,Insulin ,Age Factors ,Type 2 Diabetes Mellitus ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Endocrinology ,Diabetes Mellitus, Type 2 ,Cerebrovascular Circulation ,Hypertension ,Female ,Neurology (clinical) ,medicine.symptom ,Insulin Resistance ,business ,Body mass index ,030217 neurology & neurosurgery - Abstract
Objective:To evaluate differences in cerebrovascular reactivity (CVR) to mild hypercapnia in obese/overweight individuals with and without insulin resistance (IR) compared to comparable lean controls.Methods:A total of 60 cognitively normal participants (20 lean controls and 24 obese/overweight individuals with and 16 without IR) were evaluated using a high spatial resolution arterial spin labeling MRI technique at rest and during mild hypercapnia. We analyzed group differences in CVR in cerebral cortex and ascertained the relationships between CVR, IR, and body mass index (BMI).Results:Obese/overweight participants with and without IR had significantly lower CVR to hypercapnia than lean controls after controlling for age, sex, and the presence of hypertension (F2,53 = 5.578, p = 0.006 = 0.174). In the obese/overweight participants with IR, there was a significant correlation between higher CVR and a measure of insulin sensitivity, even after accounting for BMI (rp = 0.575, p = 0.004). In contrast, there was no relationship between CVR and BMI when controlling for IR. No such relationships existed for the other 2 groups.Conclusions:IR is associated with impaired CVR; the relationship appears to be driven by the degree of IR and not by obesity. These rarely reported results suggest that early forms of cerebrovascular dysfunction exist among obese middle-aged individuals with significant IR but without type 2 diabetes mellitus. These functional vascular abnormalities may help explain the associations among IR, diabetes, and dementia, and suggest that interventions aiming to improve IR or CVR may help prevent cognitive decline later in life.
- Published
- 2016
20. Fitness, Insulin Sensitivity and Frontal Lobe Integrity in Overweight and Obese Adults
- Author
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Castro, Mary Grace, Venutolo, Christopher, Yau, Po Lai, and Convit, Antonio
- Subjects
Blood Glucose ,Male ,Fasting ,Middle Aged ,Overweight ,Article ,Body Mass Index ,Frontal Lobe ,C-Reactive Protein ,Oxygen Consumption ,Physical Fitness ,Linear Models ,Humans ,Insulin ,Female ,Obesity ,Insulin Resistance ,Exercise - Abstract
To formally test whether insulin sensitivity mediates the relationship between fitness and brain integrity.Eighty-four middle-aged participants without diabetes received a 6-min walk test from which maximal oxygen uptake (VO2 max) was derived, a structural magnetic resonance scan, and a medical evaluation including fasting glucose and insulin levels.This study showed significant associations between fitness, abdominal obesity, and insulin sensitivity and anterior cingulate cortex (ACC) volume as well as between ACC thickness and quantitative insulin-sensitivity check index (QUICKI). The relationship between ACC volume and VO2 max was completely mediated through QUICKI. Further, this strong association was confirmed by a single and very significant cluster on the ACC linking gray matter volume and QUICKI in a voxel-based morphometry analysis.As expected, increased abdominal obesity was associated with reductions in fitness, ACC volumes, and insulin sensitivity. Importantly, this study demonstrated a significant mediation of the relationship between VO2 max and ACC volume by QUICKI. This suggests that the links between impaired insulin sensitivity and brain abnormalities in adults carrying excess weight could be alleviated through increased physical activity and fitness.
- Published
- 2016
21. Type 2 diabetes affects hippocampus volume differentially in men and women
- Author
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R. Hempel, Antonio Convit, and R. Onopa
- Subjects
Male ,medicine.medical_specialty ,endocrine system diseases ,Endocrinology, Diabetes and Metabolism ,Type 2 diabetes ,Hippocampal formation ,Hippocampus ,Article ,chemistry.chemical_compound ,Sex Factors ,Endocrinology ,High-density lipoprotein ,Diabetes mellitus ,Internal medicine ,Internal Medicine ,medicine ,Humans ,Hippocampus (mythology) ,Aged ,business.industry ,nutritional and metabolic diseases ,Type 2 Diabetes Mellitus ,Organ Size ,Middle Aged ,medicine.disease ,Diabetes Mellitus, Type 2 ,chemistry ,Brain size ,Female ,Complication ,business - Abstract
Background Type 2 diabetes mellitus (T2DM) has been shown to result in medical complications on several organ systems including the kidneys, eyes, cardiovascular system, and most recently described the brain, including the hippocampus. There is also evidence that females are disproportionately affected by these medical complications. Brain volume reductions have also been associated with chronic low-grade inflammation and dyslipidaemia. This study investigated the relationships among T2DM, gender, inflammation, dyslipidaemia, and hippocampal volumes. Method Participant groups consisted of 40 obese adults with T2DM and 47 lean adults, group-matched on age, gender, race, and education. Each participant underwent medical examination including a standard panel of blood tests, a magnetic resonance imaging, and cognitive evaluation. Results We show that there is a gender difference in the association of T2DM and hippocampal volumes: diabetic women are most affected despite having better glucose control than their male counterparts. Although females with T2DM had disproportionately lower high density lipoprotein as well as better haemoglobin A1c, neither of these results explained why females with T2DM had the smallest hippocampal volumes. Conclusions These important findings indicate that in addition to the higher rate of traditional medical complication, females with T2DM are likely to suffer more brain complications than males. These observations, if supported by larger studies, suggest that in the future gender could be considered when customizing diabetes treatment. Copyright © 2011 John Wiley & Sons, Ltd.
- Published
- 2012
22. High cortisol levels are associated with low quality food choice in type 2 diabetes
- Author
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Antonio Convit, Jessica I. Cohen, and Michelle Duong
- Subjects
Male ,Hypothalamo-Hypophyseal System ,medicine.medical_specialty ,Calorie ,Hydrocortisone ,Endocrinology, Diabetes and Metabolism ,Pituitary-Adrenal System ,Type 2 diabetes ,Choice Behavior ,Article ,Body Mass Index ,Eating ,Endocrinology ,Animal science ,Internal medicine ,Diabetes mellitus ,Food choice ,Humans ,Medicine ,Aged ,Glycated Hemoglobin ,business.industry ,Case-control study ,Middle Aged ,medicine.disease ,Diet Records ,Diabetes Mellitus, Type 2 ,Food ,Case-Control Studies ,Linear Models ,Female ,Hemoglobin ,business ,Food quality ,Body mass index ,Biomarkers - Abstract
Hypothalamic–pituitary–adrenal (HPA) axis control may be impaired in type 2 diabetes (T2DM). Glucocorticoids increase consumption of low quality foods high in calories, sugar, and fat. We explored the relationship between cortisol levels, poor blood glucose control, and food quality choice in T2DM. Twenty-seven healthy controls were age-, gender- and education-matched to 27 T2DM participants. Standard clinical blood tests and cortisol values were measured from fasting blood samples. Participants recorded all consumed food and drink items in a consecutive 3-day food diary. Diaries were analyzed for “high quality” and “low quality” foods using a standardized method with high reliability (0.97 and 0.86, respectively). Controlling for education, body mass index (BMI) and hemoglobin A1C (HbA1C), log-transformed cortisol (LogC) predicted the percent of low quality foods (R 2 = 0.092, β = 0.360, P
- Published
- 2011
23. Disinhibited Eating in Obese Adolescents Is Associated With Orbitofrontal Volume Reductions and Executive Dysfunction
- Author
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Claire J. Hoogendoorn, Victoria Sweat, Lawrence Maayan, and Antonio Convit
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Endocrinology, Diabetes and Metabolism ,Medicine (miscellaneous) ,Neuropsychological Tests ,Article ,Executive Function ,Young Adult ,Endocrinology ,Body Size ,Humans ,Medicine ,Obesity ,Psychiatry ,Growth Disorders ,Nutrition and Dietetics ,business.industry ,Neuropsychology ,Cognition ,Feeding Behavior ,Adolescent Development ,Magnetic Resonance Imaging ,Frontal Lobe ,Cognitive test ,Inhibition, Psychological ,Cross-Sectional Studies ,Adolescent Behavior ,Disinhibition ,Female ,Orbitofrontal cortex ,medicine.symptom ,Cognition Disorders ,business ,Orbit ,Three-Factor Eating Questionnaire ,Clinical psychology ,Stroop effect ,Executive dysfunction - Abstract
In adults, obesity has been associated with disinhibited eating, decreased cortical gray matter volume, and lower performance on cognitive assessments. Much less is known about these relationships in adolescence and there are no studies assessing behavioral, cognitive, and neurostructural measures in the same group of study participants. This study examined the relationship between obesity, executive function, disinhibition, and brain volumes in relatively healthy youth. Participants included 54 obese and 37 lean adolescents. Participants received a cognitive battery, questionnaires of eating behaviors, and magnetic resonance imaging (MRI). Neuropsychological assessments included tasks targeting frontal lobe function. Eating behaviors were determined using the Three Factor Eating Questionnaire (TFEQ), and structural MRIs were performed on a 1.5 T Siemens Avanto MRI System (Siemens, Erlangen, Germany) to determine brain gray matter volumes. Lean and obese adolescents were matched on age, years of education, gender, and socioeconomic status. Relative to lean adolescents, obese participants had significantly higher ratings of disinhibition on the TFEQ, lower performance on the cognitive tests, and lower orbitofrontal cortex volume. Disinhibition significantly correlated with Body Mass Index, Stroop Color-Word score, and orbitofrontal cortex volume. This is the first report of these associations in adolescents and point to the importance of better understanding the associations between neurostructural deficits and obesity.
- Published
- 2011
24. Obesity-mediated inflammation may damage the brain circuit that regulates food intake
- Author
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Fanny Cazettes, Jessica I. Cohen, Po Lai Yau, Antonio Convit, and Hugues Talbot
- Subjects
Male ,medicine.medical_specialty ,Inflammation ,Overweight ,Fibrinogen ,Systemic inflammation ,Brain mapping ,Article ,Eating ,Internal medicine ,Neural Pathways ,Image Processing, Computer-Assisted ,medicine ,Humans ,Effective diffusion coefficient ,Obesity ,Molecular Biology ,Aged ,Brain Mapping ,General Neuroscience ,Brain ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Diffusion Tensor Imaging ,Endocrinology ,Female ,Neurology (clinical) ,medicine.symptom ,Psychology ,Developmental Biology ,medicine.drug ,Diffusion MRI - Abstract
Adiposity is associated with chronic low-grade systemic inflammation and increased inflammation in the hypothalamus, a key structure in feeding behavior. It remains unknown whether inflammation impacts other brain structures that regulate feeding behavior. We studied 44 overweight/obese and 19 lean individuals with MRI and plasma fibrinogen levels (marker of inflammation). We performed MRI-based segmentations of the medial and lateral orbitofrontal cortex (OFC) and hippocampal volumes. Gray matter (GM) volumes were adjusted for head size variability. We conducted logistic and hierarchical regressions to assess the association between fibrinogen levels and brain volumetric data. Using diffusion tensor imaging (DTI), we created apparent diffusion coefficient (ADC) maps and conducted voxelwise correlational analyses. Fibrinogen concentrations were higher among the overweight/obese (t[61] = -2.33, P = 0.023). Lateral OFC associated together with fibrinogen correctly classified those with excess of weight (accuracy = 76.2%, sensitivity = 95.5%, and specificity=31.6%). The lateral OFC volumes of overweight/obese were negatively associated with fibrinogen (r = -0.37, P = 0.016) and after accounting for age, hypertension, waist/hip ratio and lipid and sugar levels, fibrinogen significantly explained an additional 9% of the variance in the lateral OFC volume (β = -0.348, ΔR(2) = 0.093, ΔF P = 0.046). Among overweight/obese the associations between GM ADC and fibrinogen were significantly positive (P0.001) in the left and right amygdala and the right parietal region. Among lean individuals these associations were negative and located in the left prefrontal, the right parietal and the left occipital lobes. This is the first study to report that adiposity-related inflammation may reduce the integrity of some of the brain structures involved in reward and feeding behaviors.
- Published
- 2011
25. Preliminary evidence for brain complications in obese adolescents with type 2 diabetes mellitus
- Author
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W. Tsui, Christopher M. Ryan, David Javier, Po Lai Yau, Babak A. Ardekani, Antonio Convit, and S. Ten
- Subjects
Male ,medicine.medical_specialty ,Pediatrics ,Adolescent ,Endocrinology, Diabetes and Metabolism ,Type 2 diabetes ,Neuropsychological Tests ,Article ,Body Mass Index ,Insulin resistance ,Diabetes mellitus ,Internal medicine ,Internal Medicine ,medicine ,Humans ,Obesity ,Effects of sleep deprivation on cognitive performance ,business.industry ,Vascular disease ,Brain ,Type 2 Diabetes Mellitus ,medicine.disease ,Magnetic Resonance Imaging ,Endocrinology ,Diabetes Mellitus, Type 2 ,Female ,Waist Circumference ,business ,Body mass index - Abstract
Central nervous system abnormalities, including cognitive and brain impairments, have been documented in adults with type 2 diabetes who also have multiple co-morbid disorders that could contribute to these observations. Assessing adolescents with type 2 diabetes will allow the evaluation of whether diabetes per se may adversely affect brain function and structure years before clinically significant vascular disease develops.Eighteen obese adolescents with type 2 diabetes and 18 obese controls without evidence of marked insulin resistance, matched on age, sex, school grade, ethnicity, socioeconomic status, body mass index and waist circumference, completed MRI and neuropsychological evaluations.Adolescents with type 2 diabetes performed consistently worse in all cognitive domains assessed, with the difference reaching statistical significance for estimated intellectual functioning, verbal memory and psychomotor efficiency. There were statistical trends for executive function, reading and spelling. MRI-based automated brain structural analyses revealed both reduced white matter volume and enlarged cerebrospinal fluid space in the whole brain and the frontal lobe in particular, but there was no obvious grey matter volume reduction. In addition, assessments using diffusion tensor imaging revealed reduced white and grey matter microstructural integrity.This is the first report documenting possible brain abnormalities among obese adolescents with type 2 diabetes relative to obese adolescent controls. These abnormalities are not likely to result from education or socioeconomic bias and may result from a combination of subtle vascular changes, glucose and lipid metabolism abnormalities and subtle differences in adiposity in the absence of clinically significant vascular disease. Future efforts are needed to elucidate the underlying pathophysiological mechanisms.
- Published
- 2010
26. The application of the first order system transfer function for fitting The California Verbal Learning Test Learning Curve
- Author
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Charles I. Abramson, Igor I. Stepanov, Oliver T. Wolf, and Antonio Convit
- Subjects
Adult ,Male ,Transfer, Psychology ,Neuropsychological Tests ,First order system ,Transfer function ,Developmental psychology ,Immediate Recall ,Trial number ,Memory ,Humans ,Attention ,Aged ,California Verbal Learning Test ,General Neuroscience ,Regression analysis ,Middle Aged ,Verbal Learning ,Psychiatry and Mental health ,Clinical Psychology ,Free recall ,Learning curve ,Female ,Neurology (clinical) ,Psychology ,Cognitive psychology - Abstract
Very few attempts have been made to apply a mathematical model to the learning curve in the California Verbal Learning Test list A immediate recall. Our rationale was to find out whether modeling of the learning curve can add additional information to the standard CVLT-II measures. We applied a standard transfer function in the form Y = B3*exp(-B2*(X-1))+B4*(1-exp(-B2*(X-1))), where X is the trial number; Y is the number of recalled correct words, B2 is the learning rate, B3 is readiness to learn and B4 is ability to learn. The coefficients of the model were found to be independent measures not duplicating standard CVLT-II measures. Regression analysis revealed that readiness to learn (B3) and ability to learn (B4) were significantly (p < .05) higher in a group of healthy participants than in a group of participants with type 2 diabetes mellitus (T2DM), but the learning rate (B2) did not differ (p > .2). The proposed model is appropriate for clinical application and as a guide for research and may be used as a good supplemental tool for the CVLT-II and similar memory tests. (JINS, 2010, 16, 443–452.)
- Published
- 2010
27. Cognitive impairment in nondiabetic middle-aged and older adults is associated with insulin resistance
- Author
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Hannah Bruehl, Jason Hassenstab, Antonio Convit, Victoria Sweat, and V Polyakov
- Subjects
Blood Glucose ,Male ,Aging ,medicine.medical_specialty ,endocrine system diseases ,Type 2 diabetes ,Neuropsychological Tests ,Audiology ,Article ,Developmental psychology ,Executive Function ,Sex Factors ,Insulin resistance ,Memory ,medicine ,Humans ,Effects of sleep deprivation on cognitive performance ,Aged ,Glycated Hemoglobin ,Working memory ,Cognitive disorder ,Quantitative insulin sensitivity check index ,Age Factors ,Neuropsychology ,nutritional and metabolic diseases ,Cognition ,Middle Aged ,medicine.disease ,Clinical Psychology ,Neurology ,Case-Control Studies ,Female ,Neurology (clinical) ,Insulin Resistance ,Cognition Disorders ,Psychology - Abstract
To determine whether the cognitive impairments observed in adults with type 2 diabetes mellitus (T2DM) exist in preclinical disease, we compared 38 adult participants with evidence of insulin resistance (IR) to 54 age-, gender-, and education-matched control participants on a battery of neuropsychological tests. We found that participants with IR had performance reductions in declarative memory and executive functioning. When we examined IR simultaneously with other biomedical indicators with which it co-occurs, only IR itself was associated with declarative memory, and hemoglobin A1c (HbA1c) was associated with executive functioning and working memory. We conclude that individuals with insulin resistance already demonstrate similar reductions in cognitive performance as those described in T2DM.
- Published
- 2009
28. Neuroimaging supports central pathology in familial dysautonomia
- Author
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Victoria Sweat, Max J. Hilz, Hannah Bruehl, Antonio Convit, David Javier, Felicia B. Axelrod, Po Lai Yau, and Dena Berlin
- Subjects
Adult ,Male ,Pathology ,medicine.medical_specialty ,Magnetic Resonance Spectroscopy ,Adolescent ,Neuropathology ,Nerve Fibers, Myelinated ,White matter ,Young Adult ,Fractional anisotropy ,Dysautonomia, Familial ,Middle cerebellar peduncle ,medicine ,Humans ,Brain ,Dysautonomia ,Organ Size ,medicine.disease ,Magnetic Resonance Imaging ,Diffusion Tensor Imaging ,medicine.anatomical_structure ,Neurology ,Familial dysautonomia ,Anisotropy ,Female ,Neurology (clinical) ,Protons ,medicine.symptom ,Psychology ,Diffusion MRI ,Optic radiation - Abstract
Familial dysautonomia (FD) is a hereditary peripheral and central nervous system disorder with poorly defined central neuropathology. This prospective pilot study aimed to determine if MRI would provide objective parameters of central neuropathology. There were 14 study subjects, seven FD individuals (18.6 +/- 4.2 years, 3 female) and seven controls (19.1 +/- 5.8 years, 3 female). All subjects had standardized brain MRI evaluation including quantitative regional volume measurements, diffusion tensor imaging (DTI) for assessment of white matter (WM) microstructural integrity by calculation of fractional anisotropy (FA), and proton MR spectroscopy ((1)H MRS) to assess neuronal health. The FD patients had significantly decreased FA in optic radiation (p = 0.009) and middle cerebellar peduncle (p = 0.004). Voxel-wise analysis identified both GM and WM microstructural damage among FD subjects as there were nine clusters of WM FA reductions and 16 clusters of GM apparent diffusion coefficient (ADC) elevations. Their WM proportion was significantly decreased (p = 0.003) as was the WM proportion in the frontal region (p = 0.007). (1)H MRS showed no significant abnormalities. The findings of WM abnormalities and decreased optic radiation and middle cerebellar peduncle FA in the FD study group, suggest compromised myelination and WM micro-structural integrity in FD brains. These neuroimaging results are consistent with clinical visual abnormalities and gait disturbance. Furthermore the frontal lobe atrophy is consistent with previously reported neuropsychological deficits.
- Published
- 2009
29. Hypothalamic-Pituitary-Adrenal Axis Dysregulation and Memory Impairments in Type 2 Diabetes
- Author
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Isabel Dziobek, Antonio Convit, Elizabeth Javier, Melanie Rueger, Alyssa Arentoft, Aziz Tirsi, Victoria Sweat, Oliver T. Wolf, and Hannah Bruehl
- Subjects
Male ,Hypothalamo-Hypophyseal System ,endocrine system ,medicine.medical_specialty ,Hydrocortisone ,Endocrinology, Diabetes and Metabolism ,Clinical Biochemistry ,Pituitary-Adrenal System ,Context (language use) ,Type 2 diabetes ,Neuropsychological Tests ,Biochemistry ,Dexamethasone ,Cognition ,Endocrinology ,Internal medicine ,medicine ,Humans ,Memory disorder ,Glucocorticoids ,Aged ,Glycemic ,Memory Disorders ,business.industry ,Working memory ,Biochemistry (medical) ,Cognitive disorder ,Middle Aged ,medicine.disease ,Cross-Sectional Studies ,medicine.anatomical_structure ,Diabetes Mellitus, Type 2 ,Female ,Cognition Disorders ,business ,hormones, hormone substitutes, and hormone antagonists ,Hypothalamic–pituitary–adrenal axis ,medicine.drug - Abstract
Context: There is evidence of both hypothalamic-pituitary-adrenocortical (HPA) axis and cognitive dysfunction in type 2 diabetes mellitus (T2DM). However, the exact nature and the associations between these abnormalities remain unclear. Objectives: The aim of the study was to characterize the nature of the HPA dysregulation in T2DM and ascertain whether impaired cognition in T2DM could be attributed to these abnormalities. Design: A cross-sectional study was performed, contrasting matched groups on HPA axis function and cognition by using the combined dexamethasone (DEX)/CRH test and a neuropsychological battery assessing declarative and working memory, attention, and executive function. Setting: The study was conducted in a research clinic in an academic medical center. Participants: Participants were volunteers functioning in the cognitively normal range. We studied 30 middle-aged individuals with T2DM, on average 7.5 yr since diabetes diagnosis, and 30 age-, gender-, and education-matched controls. Main Outcome Measures: Basal cortisol levels, cortisol levels during the DEX/CRH test, and performance on neuropsychological tests were measured. Results: Individuals with T2DM had elevated basal plasma cortisol levels, higher levels after DEX suppression, and a larger response to CRH (all P ≤ 0.005). Among individuals with T2DM, cortisol levels during the DEX/CRH test were positively associated with glycosylated hemoglobin (P = 0.05), independent of age, body mass index, hypertension, and dyslipidemia. Diabetic subjects showed cognitive impairments restricted to declarative memory. Across all subjects, declarative memory was inversely associated with cortisol levels; however, these associations were subsumed by glycemic control (glycosylated hemoglobin). Conclusions: HPA hyperactivity and declarative memory deficits are present in T2DM. Both alterations may reflect the negative impact of poor glycemic control on the hippocampal formation.
- Published
- 2007
30. Diffuse cutaneous leishmaniasis responds to miltefosine but then relapses
- Author
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M Polegre, I Mendoza, C Ravel, Angela Avila, Olga Zerpa, Jacinto Convit, N Matos, F Pratlong, Belkis J. Menoni Blanco, and Marian Ulrich
- Subjects
Adult ,Male ,medicine.medical_specialty ,Cellular immunity ,Adolescent ,Phosphorylcholine ,Antiprotozoal Agents ,Drug Resistance ,Leishmaniasis, Diffuse Cutaneous ,Dermatology ,Drug resistance ,Gastroenterology ,Cutaneous leishmaniasis ,Recurrence ,Protozoan infection ,Internal medicine ,medicine ,Humans ,Treatment Failure ,Child ,Adverse effect ,Miltefosine ,business.industry ,Leishmaniasis ,Middle Aged ,medicine.disease ,Visceral leishmaniasis ,Child, Preschool ,Immunology ,Quality of Life ,Female ,business ,medicine.drug - Abstract
Summary Background Diffuse cutaneous leishmaniasis (DCL), although rare, is profoundly incapacitating. At present there is no successful treatment for this progressive protozoan infection, which is associated with the absence of specific cell-mediated immunity (CMI) to Leishmania. This disease shares features with visceral leishmaniasis (VL), including specific CMI inactivity during active disease and a heavy parasitic burden, but VL responds well to treatment. Miltefosine is the first orally administered drug which has shown efficacy in the treatment of VL; it has not been adequately evaluated in the treatment of DCL. Objectives To evaluate the efficacy of miltefosine in the treatment of DCL, using clinical, parasitological, histopathological and immunological criteria. Methods Sixteen patients with DCL were treated with miltefosine, 2·0–2·5 mg kg−1 daily, for variable periods of time (75–218 days). Patients were hospitalized for the first month and evaluated every 2 weeks until the termination of treatment with routine laboratory chemistry, percentage clinical improvement, presence of parasites in skin smears, growth of parasites in culture medium and in hamsters, histopathological characteristics of the granulomas, adverse side-effects, and reactivity to leishmanin skin test antigen. Further cycles of treatment were given in some of these patients, particularly after suspension of treatment was followed by relapse. Results Patients showed dramatic clinical improvement and reduction in the parasite burden by day 15 after the initiation of treatment, which continued while treatment was maintained. By day 45, 15 patients showed 80–90% clinical improvement. Nevertheless, suspension of treatment was followed by the development of new lesions in all but one patient. Inoculation in hamsters was observed to be the most sensitive technique to detect persisting parasites. Adverse events were very mild. Conclusions Miltefosine produced a dramatic clinical and parasitological response in patients with DCL and improvement continued during drug administration, but with a single exception all patients presented new lesions after suspension of treatment. There was no histological or skin test evidence to suggest the development of CMI during treatment, which may be an indispensable criterion for the evaluation of potentially effective drugs against DCL.
- Published
- 2007
31. Knowing What Others Know, Feeling What Others Feel
- Author
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Antonio Convit, Oliver T. Wolf, Kimberley Rogers, Jason Hassenstab, and Isabel Dziobek
- Subjects
Adult ,Male ,Psychotherapist ,Personality Inventory ,media_common.quotation_subject ,Personal distress ,Empathy ,Interpersonal communication ,Simulation theory of empathy ,Cognition ,Social cognition ,Humans ,Interpersonal Relations ,Occupations ,media_common ,Professional-Patient Relations ,Facial Expression ,Psychotherapy ,Affect ,Psychiatry and Mental health ,Distress ,Social Perception ,Feeling ,Visual Perception ,Female ,Cues ,Psychology - Abstract
There has been considerable interest in assessing whether psychotherapists have enhanced abilities in empathy and whether those abilities influence treatment outcomes. However, to date, studies have been hindered by inconsistent definitions of empathy and a reliance on assessment via self-report. The unique aim of this study was to ascertain the empathic abilities of psychotherapists using a multidimensional battery consisting of objective and self-report measures. We compared 19 therapists and 19 well-matched control subjects on several measures of empathy. On tests emphasizing the cognitive aspects of empathy, therapists were no different from controls when making inferences based on facial expressions but were significantly better when making inferences based on language. On a test emphasizing the emotional aspects of empathy, therapists did not report to be more empathically concerned than controls; however, on a test of emotion regulation, they reported less personal distress in response to the distress of others. In sum, therapists were better able to interpret the verbal cues of others and described themselves as more emotionally controlled in response to tense interpersonal situations.
- Published
- 2007
32. The ‘amygdala theory of autism’ revisited: Linking structure to behavior
- Author
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Oliver T. Wolf, Antonio Convit, Stefan Fleck, Isabel Dziobek, and Kimberley Rogers
- Subjects
Adult ,Male ,Head size ,Cognitive Neuroscience ,Emotions ,Experimental and Cognitive Psychology ,Neuropsychological Tests ,Amygdala ,Developmental psychology ,Behavioral Neuroscience ,Social cognition ,Theory of mind ,medicine ,Humans ,Emotion recognition ,Asperger Syndrome ,Social Behavior ,Neurologic Examination ,Behavior ,Recognition, Psychology ,medicine.disease ,Magnetic Resonance Imaging ,Developmental disorder ,medicine.anatomical_structure ,nervous system ,Asperger syndrome ,Autism ,Female ,Psychology ,Head ,psychological phenomena and processes - Abstract
The 'amygdala theory of autism' suggests a crucial role for the amygdala in the neurobiological basis of autism spectrum disorders. However, to date evidence is lacking of a direct relationship between amygdala measures and behavioral manifestations of autism in affected individuals. In 17 adult individuals with Asperger syndrome (AS) and 17 well-matched controls we therefore assessed associations between MRI-derived amygdala volume and behavioral variables of emotion recognition and social cognition, as well as with core AS symptomatology. Results revealed that individuals with AS exhibited impairments in emotion recognition and social cognition compared to controls and also showed atypical relationships between amygdala volumes and overall head size. We found positive associations between emotional and social understanding and amygdala volume in the control group, but not in the AS group. In the AS group however, amygdala size was negatively related to diagnostic parameters, with smaller amygdala volumes involving higher levels of restricted-repetitive behavior domains. Our data seem to indicate that in AS the amygdala is not crucially involved in social and emotional understanding. It may, however, be a mediator for narrow interest patterns and the imposition of routines and rituals. Our data, in conjunction with current literature, seem to argue for a modification of the 'amygdala theory of autism'.
- Published
- 2006
33. Retinal vessel alterations and cerebral white matter microstructural damage in obese adolescents with metabolic syndrome
- Author
-
Minsung Kim, Po Lai Yau, Antonio Convit, and Aziz Tirsi
- Subjects
Male ,medicine.medical_specialty ,Central retinal artery ,Adolescent ,Childhood obesity ,Article ,Body Mass Index ,White matter ,chemistry.chemical_compound ,Young Adult ,Insulin resistance ,Diabetes mellitus ,medicine.artery ,Internal medicine ,medicine ,Humans ,Obesity ,Metabolic Syndrome ,business.industry ,Retinal Vessels ,Retinal ,medicine.disease ,White Matter ,Endocrinology ,medicine.anatomical_structure ,Cross-Sectional Studies ,Diffusion Tensor Imaging ,chemistry ,Case-Control Studies ,Pediatrics, Perinatology and Child Health ,Cardiology ,Female ,Metabolic syndrome ,Waist Circumference ,business ,Body mass index - Abstract
Cerebral white matter (WM) damage has been reported in childhood obesity and in metabolic syndrome (MetS) but mechanisms remain unclear.To ascertain whether adolescents with MetS have retinal vessel alterations and if the anticipated reductions in retinal arteriolar diameter are associated with diminished cerebral WM microstructural integrity and to test a model for vascular etiology of the WM abnormalities.Cross-sectional study of the brain correlates of obesity and related metabolic disease in youths. This study was conducted at the Brain, Obesity, and Diabetes Laboratory, New York University School of Medicine, New York. Thirty-nine obese adolescents with MetS and 51 matched adolescents without MetS received comprehensive endocrine, neuropsychological, retinal vessel, and diffusion tensor imaging-based cerebral WM evaluations.Retinal arteriolar diameter, cerebral WM microstructural integrity, waist circumference, and insulin resistance.Obese adolescents with MetS had significant reductions in retinal arteriolar diameter relative to adolescents without MetS (mean [SD] central retinal arteriolar equivalent, 182.35 [16.10] vs. 198.62 [19.03] μm, respectively; P .001). The greater the number of MetS criteria present, the greater the reduction was in retinal arteriolar diameter (β = -8.61; ∆r2 = 0.335; ∆F1,83 = 70.79; P .001). We found that abdominal obesity (waist circumference) was the strongest MetS component related to reductions in retinal arteriolar diameter (rp[85] = -0.661; P .001), and importantly, for the first time to our knowledge, we demonstrated that its effect was partially mediated by comorbid insulin resistance (indirect effect = -0.1355 [95% CI, -0.2471 to -0.0593]; Z = -2.56; P = .01). Consistent with our prior report of nondiabetic adolescents with MetS, we also uncovered cerebral WM microstructural damage. These subtle WM changes were associated with reductions in retinal arteriolar diameter, a proxy for cerebral microvascular health (3150 voxels or 3.15 cm3; P .001). Importantly, some of the WM regions showing lower microstructural integrity also demonstrated associations with retinal arteriolar diameter, suggesting that the observed WM pathology is likely vascular in nature.We document, for the first time to our knowledge, the associations between retinal vessel alterations and subclinical WM pathology among obese adolescents with MetS. This suggests that the subtle WM pathology in adolescents with MetS may have a vascular origin. Future work should include direct assessments of cerebral microvascular health.
- Published
- 2014
34. Erratum to: Autologous tumor lysate/Bacillus Calmette–Guérin immunotherapy as an adjuvant to conventional breast cancer therapy
- Author
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J. Convit, H. Montesinos, H. Oviedo, G. Romero, B. Maccarone, E. Essenfeld, A. Convit, and L. E. Palacios
- Subjects
Cancer Research ,Mice, Inbred BALB C ,Guinea Pigs ,Antineoplastic Agents ,Breast Neoplasms ,General Medicine ,Chemoradiotherapy ,Cancer Vaccines ,Mycobacterium bovis ,Survival Rate ,Mice ,Oncology ,Adjuvants, Immunologic ,Cricetinae ,Animals ,Humans ,Female ,Erratum - Abstract
Autologous tumor cell vaccines rely on the concept of preserving an individual's own tumorigenic makeup, expressing its unique set of tumor-associated antigens as well as antigenic elements from the surrounding stroma. These autologous tumor characteristics are usually presented with an immune adjuvant in the hopes of enhancing an immune response.The autologous vaccine we used was composed of tumor cells combined with BCG and formalin. Animal safety and toxicity were evaluated using mice tumors for the immunotherapy. A small number of patients with advanced stage breast cancer were recruited for an uncontrolled study, using the vaccine solely or combined with chemotherapy/radiotherapy.The immunotherapy had shown to be safe in mice and humans. Upon a 5-year follow-up, the survival rate was 60 % for the combined treatment.The data suggest that the combined treatment could be a feasible and safe therapeutic strategy. However, further controlled studies should be conducted.
- Published
- 2016
35. Subjective memory complaints in aging are associated with elevated cortisol levels
- Author
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Isabel Dziobek, Oliver T. Wolf, Mony J. de Leon, Victoria Sweat, Pauline McHugh, Elizabeth Javier, and Antonio Convit
- Subjects
Male ,Senescence ,Hypothalamo-Hypophyseal System ,Aging ,medicine.medical_specialty ,Hydrocortisone ,Corticotropin-Releasing Hormone ,Radioimmunoassay ,Pituitary-Adrenal System ,Enzyme-Linked Immunosorbent Assay ,Neuropsychological Tests ,Dexamethasone ,Body Mass Index ,Basal (phylogenetics) ,Sex Factors ,Adrenocorticotropic Hormone ,Surveys and Questionnaires ,medicine ,Humans ,Big Five personality traits ,Psychiatry ,Depression (differential diagnoses) ,Demography ,Analysis of Variance ,Memory Disorders ,Psychological Tests ,Depression ,General Neuroscience ,Cognition ,Middle Aged ,Circadian Rhythm ,Female ,Neurology (clinical) ,Analysis of variance ,Geriatrics and Gerontology ,Psychology ,Glucocorticoid ,Developmental Biology ,medicine.drug ,Clinical psychology - Abstract
The origin and clinical significance of subjective memory complaints among middle aged and older individuals is not well understood. Associations with objective memory impairments, personality traits or mood disturbances have been reported. Elevated cortisol levels occur in aging and depression and causal links to cognitive or emotional problems have been suggested. The goal of this study was to investigate the associations between basal and feedback indices of cortisol regulation and subjective memory impairment in a sample of healthy middle aged and older subjects (mean age 61.8 years) with (n = 27) and without (n = 19) subjective memory complaints. Participants with memory complaints had both higher basal cortisol levels and higher cortisol levels after dexamethasone. There was a significant group by gender interaction for basal cortisol levels, where women without memory complaints showed significantly lower cortisol levels, whereas no such difference was found for the men. All effects were not due to slight differences in depression scores. Differences in personality traits or in stress susceptibility might underlie the present findings. Future studies of memory complaints should take a comprehensive approach including relevant endocrine parameters.
- Published
- 2005
36. Hypertension and Hypothalamo-Pituitary-Adrenal Axis Hyperactivity Affect Frontal Lobe Integrity
- Author
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Pauline McHugh, Abdul Bayoumy, Antonio Convit, Stefan M. Gold, Kimberley Rogers, and Isabel Dziobek
- Subjects
Male ,Hypothalamo-Hypophyseal System ,Pituitary gland ,medicine.medical_specialty ,Hydrocortisone ,Endocrinology, Diabetes and Metabolism ,Intelligence ,Clinical Biochemistry ,Population ,Pituitary-Adrenal System ,Blood Pressure ,Biochemistry ,Body Mass Index ,Temporal lobe ,Endocrinology ,Atrophy ,Adrenocorticotropic Hormone ,Reference Values ,Internal medicine ,medicine ,Humans ,education ,Glucocorticoids ,Aged ,education.field_of_study ,business.industry ,Biochemistry (medical) ,Middle Aged ,medicine.disease ,Frontal Lobe ,Blood pressure ,medicine.anatomical_structure ,Frontal lobe ,Area Under Curve ,Hypertension ,Female ,business ,Glucocorticoid ,medicine.drug - Abstract
Chronically elevated cortisol levels have been associated with elevated blood pressure, brain atrophy, and cognitive impairments. In this cross-sectional exploratory study, we assessed whether hypertension was related to hypothalamo-pituitary-adrenal axis hyperactivity and whether this may in part explain prefrontal brain atrophy and cognitive impairments in this population. We studied 27 patients with hypertension and 27 normotensive control subjects. Glucocorticoid feedback was assessed using the combined dexamethasone-CRH test. All participants completed a neuropsychological battery and received brain magnetic resonance imaging for volumetric measurement of frontal and medial temporal lobe regions. Hypertension was significantly associated with impaired glucocorticoid feedback control after statistically controlling for age, gender, and body mass index (P = 0.01). Hypertensive patients also showed a trend toward reductions in frontal lobe volume (P = 0.09) and had significantly lower scores in one of two tests of executive function (P = 0.03). Significant correlations were observed between hypothalamo-pituitary-adrenal hyperactivity and frontal lobe atrophy. Our data indicate that impaired glucocorticoid feedback control may partly account for the prefrontal volume reductions present in patients with hypertension. Future studies assessing the impact of hypertension on the brain should include cortisol assessments.
- Published
- 2005
37. Atypical cutaneous leishmaniasis in Central America: possible interaction between infectious and environmental elements
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Jacinto Convit, H. De Lima, Jimmy Castillo, Marian Ulrich, M. Pérez, L.N. Araya, A. Viquez, H. Rojas, and J. Hung
- Subjects
Adult ,Costa Rica ,Male ,medicine.medical_specialty ,Pathology ,Adolescent ,Leishmaniasis, Cutaneous ,Nicaragua ,Cutaneous leishmaniasis ,parasitic diseases ,Biopsy ,medicine ,Animals ,Humans ,Skin ,Skin Tests ,Leishmania ,Granuloma ,biology ,medicine.diagnostic_test ,Public Health, Environmental and Occupational Health ,Anatomical pathology ,Leishmaniasis ,Environmental Exposure ,General Medicine ,Leishmania chagasi ,Silicon Dioxide ,medicine.disease ,biology.organism_classification ,Infectious Diseases ,Female ,Parasitology ,Histopathology ,Aluminum - Abstract
Biopsies of 71 cases of atypical cutaneous leishmaniasis from Costa Rican patients were evaluated by histopathological procedures and attempts were made to culture Leishmania from nine biopsies. Leishmanin skin tests were carried out in 31 patients and 112 healthy individuals. Additional biopsies from 19 patients from Nicaragua were evaluated by routine histopathology. Ten biopsies were studied by confocal and nine by scanning electron microscopy. Inorganic material was analysed using an electron probe for microanalysis. Leishmania parasites were isolated from only two biopsies, but 90.3% of the patients from Costa Rica were leishmanin-positive, as were 27.7% of healthy individuals. Routine histopathological studies revealed naked granulomas formed by differentiated macrophages. Abundant inorganic material was observed in sections examined by confocal microscopy. Electron probe analysis revealed that silica and aluminium were the predominant elements in large particles. We postulate that the presence of this inorganic material, possibly of volcanic origin, in the skin may modulate the immunological response to Leishmania and may inhibit visceralization in the cases caused by Leishmania chagasi.
- Published
- 2005
38. Atrophy rate in medial temporal lobe during progression of Alzheimer disease
- Author
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Henry Rusinek, Salomao Segal, M. J. de Leon, Antonio Convit, S. De Santi, W. Tsui, Y. Endo, and Dina Frid
- Subjects
Male ,Pathology ,medicine.medical_specialty ,Brain tissue ,Neuropsychological Tests ,Temporal lobe ,Central nervous system disease ,Imaging, Three-Dimensional ,Degenerative disease ,Atrophy ,Alzheimer Disease ,medicine ,Humans ,Aged ,Aged, 80 and over ,Atrophy rate ,medicine.diagnostic_test ,Magnetic resonance imaging ,medicine.disease ,Magnetic Resonance Imaging ,Temporal Lobe ,Disease Progression ,Female ,Neurology (clinical) ,Alzheimer's disease ,Psychology ,psychological phenomena and processes ,Follow-Up Studies - Abstract
Objective: To establish the progression of brain atrophy rates in patients with a known date of onset of Alzheimer disease (AD).Methods: Each of 18 subjects had two high-resolution T1-weighted three-dimensional MRI examinations. The two MRIs were coregistered and the annual rate of brain tissue atrophy was derived both for the entire brain and regionally for the left and right medial temporal lobe (MTL). Time since onset (TSO) of AD, defined as the interval between the date of onset and the midpoint of MRI dates, ranged from −2.9 to 4.2 years.Results: In patients with AD, TSO was a correlate of the atrophy rate for both the left MTL (R2 = 0.58, p = 0.001) and right MTL (R2 = 0.30, p = 0.03). When serial measurements were applied to a control group of 21 cognitively normal elderly subjects, MTL atrophy rate classified the group membership (AD vs normal cognition) with an accuracy of 92.3%.Conclusion: Increased annual atrophy rate in the medial temporal lobe is a potential diagnostic marker of the progression of Alzheimer disease.
- Published
- 2004
39. Prevalence of Helicobacter pylori infection in Warao lineage communities of Delta Amacuro State, Venezuela
- Author
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María Correnti, Diana Ortiz, Jacinto Convit, Orquídea L. Rodríguez, Isabel Hagel, and María Eugenia Cavazza
- Subjects
Adult ,Male ,Microbiology (medical) ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,lcsh:RC955-962 ,lcsh:QR1-502 ,lcsh:Microbiology ,Helicobacter Infections ,Lineage (anthropology) ,Serology ,Feces ,Age Distribution ,Antigen ,Risk Factors ,Seroepidemiologic Studies ,Prevalence ,Humans ,Child ,Saliva ,Antigens, Bacterial ,Gastrointestinal tract ,Helicobacter pylori ,seroprevalence ,biology ,Indians, South American ,Risk of infection ,Infant ,Venezuela ,Antibodies, Bacterial ,Titer ,secretory IgA ,Child, Preschool ,Immunoglobulin G ,Immunoglobulin A, Secretory ,Immunology ,biology.protein ,Female ,Antibody - Abstract
The purpose of this study was the evaluation of Helicobacter pylori infections in children and adults from two indigenous communities of Delta Amacuro State, Venezuela, that differ in hygienic conditions of the housing. The evaluation was performed in 98 children (mean age 7 ± 3.37 years) and their mothers (33.96 ± 13.77 years) from two communities of Warao lineage. Anti-H. pylori serum IgG and secretory anti-H. pylori IgA antibodies were de-termined, as well as total secretory IgA and H. pylori antigens in feces. Serological prevalence of H. pylori infection was 38% in children and 84% their in mothers. Children from the community that had the most deficient sanitary and hygienic conditions had significantly lower titers of specific IgG antibodies and total secretory IgA (P < 0.0001) and a high percentage of them had H. pylori antigens in their feces (P < 0.0001). The levels of specific IgA were similar in both groups. The results indicate that in these populations there is a high prevalence of H. pylori infection and that poor hygienic conditions can increase the risk of infection and damage to the gastrointestinal tract.
- Published
- 2003
40. Teleassessment Compared with Live Assessment of Pressure Ulcers in a Wound Clinic: A Pilot Study
- Author
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Lauro S. Halstead, Steven Woods, Michael J Rosen, Matt Elrod, Tom Dang, and Rafael J Convit
- Subjects
Adult ,Male ,Rehabilitation hospital ,medicine.medical_specialty ,Referral ,MEDLINE ,Telepathology ,Pilot Projects ,Dermatology ,Photography ,medicine ,Humans ,Medical history ,Spinal cord injury ,Nursing Assessment ,Aged ,Wound clinic ,Observer Variation ,Pressure Ulcer ,Advanced and Specialized Nursing ,business.industry ,Outcome measures ,Middle Aged ,medicine.disease ,Surgery ,Plastic surgery ,Physical therapy ,Female ,business - Abstract
Objective To compare teleassessment of pressure ulcers in individuals with spinal cord injury in a simulated remote setting with in-person assessments in a wound clinic. Design Pressure ulcers were assessed using a 3-megapixel digital camera; images of each ulcer were forwarded to a laptop in a separate room. Nurses completed a medical history and wound database form. A plastic surgeon reviewed the images and database and completed a questionnaire concerning the "remote" teleassessment or teleconsultation. When needed, the plastic surgeon obtained additional information using live audio-video interaction with the participant or nurse. After the teleassessment was completed, the plastic surgeon then assessed the individual and wound live and completed the same questionnaire used for the teleassessment. Setting Wound clinic of a rehabilitation hospital. Participants Individuals with a spinal cord injury and 1 or more pressure ulcers who were seen for initial or follow-up evaluations. Main outcome measures Percentage of agreement for teleassessment versus live responses to 4 yes/no questions regarding the need to change wound management, satisfaction with teleassessment, need for referral, and need for additional information. Main results Seventeen individuals with 20 wounds were evaluated. The total percentage of agreement for teleassessment versus live decisions was 89% (80% to 95%). The highest percentages of agreement were for the need to change wound management and the need for referral (both 95%); the lowest percentages of agreement were for satisfaction with teleassessment for making treatment decisions (85%) and the need to obtain additional information (80%). Conclusions Teleassessment of pressure ulcers in individuals with a spinal cord injury using digital images and a standard database compared well with in-person assessment, which is similar to results reported for other pathologic conditions.
- Published
- 2003
41. Epidemiological and immunological aspects of human visceral leishmaniasis on Margarita Island, Venezuela
- Author
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Steven G. Reed, Jacinto Convit, Marian Ulrich, Centeno M, Vestalia Rodríguez, Concepción Avila, Doris Belizario, Olga Zerpa, and Margarita Benitez
- Subjects
Male ,Protozoan Proteins ,lcsh:QR1-502 ,Antibodies, Protozoan ,Disease ,lcsh:Microbiology ,Serology ,Epidemiology ,Dog Diseases ,Child ,rK39 antigen ,biology ,Transmission (medicine) ,Incidence ,Middle Aged ,Child, Preschool ,Healthy individuals ,Leishmaniasis, Visceral ,Female ,Antibody ,Adult ,Microbiology (medical) ,medicine.medical_specialty ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,lcsh:RC955-962 ,Antigens, Protozoan ,Enzyme-Linked Immunosorbent Assay ,Statistics, Nonparametric ,Age Distribution ,Dogs ,Antigen ,parasitic diseases ,medicine ,Animals ,Humans ,American visceral leishmaniasis ,Sex Distribution ,Analysis of Variance ,business.industry ,Infant, Newborn ,Infant ,leishmanin reactions ,medicine.disease ,Venezuela ,Margarita Island ,Visceral leishmaniasis ,Immunology ,biology.protein ,business ,control ,Leishmania donovani - Abstract
Sixty-five patients were diagnosed with visceral leishmaniasis (VL) on Margarita Island in the decade from 1990 to1999; 86.2% were
- Published
- 2002
42. Longitudinal cerebrospinal fluid tau load increases in mild cognitive impairment
- Author
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Henry Rusinek, P. Lesbre, John F. DeBernardis, Daniel J. Kerkman, Chaim Tarshish, Peter Davies, W. Tsui, Pankaj Mehta, Susan DeSanti, John T. Poirier, Antonio Convit, Thomas Wisniewski, C. Caraos, Ray Zinkowski, F Qadri, A Gary, S. Segal, M. J. de Leon, and L. A. Saint Louis
- Subjects
Male ,medicine.medical_specialty ,Pathology ,Longitudinal study ,Amyloid beta ,Tau protein ,Enzyme-Linked Immunosorbent Assay ,tau Proteins ,Severity of Illness Index ,Statistics, Nonparametric ,Central nervous system disease ,Cerebrospinal fluid ,Reference Values ,Internal medicine ,mental disorders ,medicine ,Humans ,Longitudinal Studies ,Aged ,Amyloid beta-Peptides ,biology ,business.industry ,General Neuroscience ,Cognitive disorder ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Peptide Fragments ,Cross-Sectional Studies ,medicine.anatomical_structure ,Ventricle ,Cardiology ,biology.protein ,Female ,Alzheimer's disease ,Cognition Disorders ,business ,Biomarkers ,Follow-Up Studies - Abstract
Cross-sectional cerebrospinal fluid (CSF) levels of tau and amyloid (A) beta (beta) are of diagnostic importance for Alzheimer's disease (AD) and mild cognitive impairment (MCI). However, most longitudinal studies of tau fail to demonstrate progression. Because predominantly brain-derived proteins such as tau, have higher ventricle to lumbar ratios, we hypothesized that adjusting for the ventricular enlargement of AD would correct for the dilution of tau, and improve detection of longitudinal change. Abeta which is not exclusively brain derived, shows a ratio1, and no benefit was expected from adjustment. In a 1 year longitudinal study of eight MCI and ten controls, we examined CSF levels of hyperphosphorylated (P) tau231, Abeta40, and Abeta42. In cross-section, MCI patients showed elevated Ptau231 and Abeta40 levels, and greater ventricular volumes. Longitudinally, only after adjusting for the ventricular volume and only for Ptau231, were increases seen in MCI. Further studies are warranted on mechanisms of tau clearance and on using imaging to interpret CSF studies.
- Published
- 2002
43. Salivary cortisol day profiles in elderly with mild cognitive impairment
- Author
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Oliver T. Wolf, Elissa Thorn, Mony J. de Leon, and Antonio Convit
- Subjects
Adult ,Male ,endocrine system ,medicine.medical_specialty ,Hydrocortisone ,Endocrinology, Diabetes and Metabolism ,Neuropsychological Tests ,Endocrinology ,Degenerative disease ,Alzheimer Disease ,Internal medicine ,Memory span ,medicine ,Humans ,Risk factor ,Saliva ,Biological Psychiatry ,Aged ,Sex Characteristics ,Endocrine and Autonomic Systems ,Cognition ,medicine.disease ,Neurosecretory Systems ,Psychiatry and Mental health ,Mental Recall ,Female ,Alzheimer's disease ,Cognition Disorders ,Psychology ,hormones, hormone substitutes, and hormone antagonists ,Glucocorticoid ,medicine.drug ,Sex characteristics - Abstract
It is unknown whether hypothalamus-pituitary-adrenal (HPA) axis dysfunction is associated with the memory impairments observed among elderly participants with mild cognitive impairment (MCI), a group considered at increased risk for Alzheimer's disease (AD). Therefore, salivary cortisol levels were measured at six points over the course of the day while at-home in MCI participants (n=16), normal elderly (n=28), and young controls (n=14). Results revealed that MCI participants did not show elevated salivary cortisol levels. The 9 a.m. cortisol level of the MCI group was significantly lower than the 9 a.m. level of the young controls, but did not differ from those of the normal elderly group. In contrast to the other two groups, within the MCI group mean cortisol levels were inversely related to immediate recall of paragraphs. No association was observed between mean cortisol levels and performance in paired associates and digit span. Whether cortisol levels, in conjunction with other factors, such as hippocampal volume, will lead to improved prediction of future decline to AD in participants with MCI remains to be established in longitudinal studies.
- Published
- 2002
44. Cerebral perfusion in insulin resistance and type 2 diabetes
- Author
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Antonio Convit, Aziz Tirsi, Henry Rusinek, Pippa Storey, Wai Hon Tsui, Svetlana Azova, Olivia Frosch, Po Lai Yau, and Jenny Ha
- Subjects
Male ,medicine.medical_specialty ,Type 2 diabetes ,Insulin resistance ,Cognition ,Diabetes mellitus ,Internal medicine ,medicine ,Humans ,Prospective Studies ,Cerebral perfusion pressure ,Analysis of Variance ,business.industry ,Type 2 Diabetes Mellitus ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Blood pressure ,Endocrinology ,Neurology ,Cerebral blood flow ,Diabetes Mellitus, Type 2 ,Case-Control Studies ,Cerebrovascular Circulation ,Cardiology ,Female ,Original Article ,Neurology (clinical) ,Insulin Resistance ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Blood Flow Velocity - Abstract
Cerebral perfusion was evaluated in 87 subjects prospectively enrolled in three study groups—healthy controls (HC), patients with insulin resistance (IR) but not with diabetes, and type 2 diabetes mellitus (T2DM). Participants received a comprehensive 8-hour clinical evaluation and arterial spin labeling magnetic resonance imaging (MRI). In order of decreasing significance, an association was found between cerebral blood flow (CBF) and sex, waist circumference, diastolic blood pressure (BP), end tidal CO2, and verbal fluency score ( R2=0.27, F=5.89, P2 relationship (slope=−0.012) in the normocapnic range, in contrast to a strong relationship in healthy brains (slope=0.800) and intermediate response (slope=0.445) in diabetic patients. Since the majority of T2DM but few IR subjects were aggressively treated with blood glucose, cholesterol, and BP lowering medications, our finding could be attributed to the beneficial effect of these drugs.
- Published
- 2014
45. Volumetric analysis of the pre-frontal regions: findings in aging and schizophrenia
- Author
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Oliver T. Wolf, Robert Cancro, Marilou B. Patalinjug, Conrad Caraos, Emad Kandil, Les A. Saint Louis, Mony J. de Leon, Adam J. Scherer, and Antonio Convit
- Subjects
Adult ,Male ,Cingulate cortex ,Aging ,Psychosis ,medicine.medical_specialty ,Neuroscience (miscellaneous) ,Prefrontal Cortex ,Inferior frontal gyrus ,Neuropsychological Tests ,Audiology ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Cognitive decline ,Prefrontal cortex ,Aged ,medicine.disease ,Magnetic Resonance Imaging ,Psychiatry and Mental health ,Frontal lobe ,Superior frontal gyrus ,Schizophrenia ,Female ,Orbitofrontal cortex ,Cognition Disorders ,Psychology ,Neuroscience - Abstract
Frontal lobe dysfunction is thought to be involved in schizophrenia and age-associated cognitive decline. Frontal lobe volume changes have been investigated in these conditions using MRI, but results have been inconsistent. Few volumetric MRI protocols exist that divide the pre-frontal cortex into its sub-regions. In the present article, we describe a new method, which allows assessment of the superior, middle and inferior frontal gyrus, as well as the orbitofrontal and cingulate regions. The method uses multiple planes to help guide the anatomical decisions and combines this with a geometric approach utilizing readily apparent anatomical landmarks. Using this protocol, the frontal lobe volumes in young healthy subjects were contrasted with those of young schizophrenic patients and Ž. elderly healthy subjects nine male subjects per group . The results showed that the method could be reproduced Ž. with high reliability r 0.880.99 . Schizophrenic as well as old subjects had specific significant reductions in the icc superior frontal gyrus and orbitofrontal regions compared with the young group. However, old and schizophrenic subjects did not differ from each another. No volume differences were observed in the other three regions assessed. Whether or not these volume reductions reflect a common pathological process remains to be investigated in future studies. 2001 Elsevier Science Ireland Ltd. All rights reserved.
- Published
- 2001
46. Hippocampal formation glucose metabolism and volume losses in MCI and AD
- Author
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Susan De Santi, Joanna S. Fowler, Emad Kandil, Alexandra Roche, Wai Hon Tsui, David J. Schlyer, Mony J. de Leon, Madhu Boppana, Antonio Convit, Katherine Daisley, Gene-Jack Wang, Chaim Tarshish, and Henry Rusinek
- Subjects
Male ,Aging ,medicine.medical_specialty ,Pathology ,Hippocampus ,Hippocampal formation ,Sensitivity and Specificity ,Degenerative disease ,Atrophy ,Alzheimer Disease ,Predictive Value of Tests ,Internal medicine ,mental disorders ,medicine ,Humans ,Aged ,Aged, 80 and over ,Neocortex ,General Neuroscience ,Cognitive disorder ,Middle Aged ,Entorhinal cortex ,medicine.disease ,Magnetic Resonance Imaging ,Glucose ,medicine.anatomical_structure ,Cardiology ,Female ,Neurology (clinical) ,Geriatrics and Gerontology ,Alzheimer's disease ,Cognition Disorders ,Psychology ,Tomography, Emission-Computed ,Developmental Biology - Abstract
We used MRI volume sampling with coregistered and atrophy corrected FDG-PET scans to test three hypotheses: 1) hippocampal formation measures are superior to temporal neocortical measures in the discrimination of normal (NL) and mild cognitive impairment (MCI); 2) neocortical measures are most useful in the separation of Alzheimer disease (AD) from NL or MCI; 3) measures of PET glucose metabolism (MRglu) have greater diagnostic sensitivity than MRI volume. Three groups of age, education, and gender matched NL, MCI, and AD subjects were studied. The results supported the hypotheses: 1) entorhinal cortex MRglu and hippocampal volume were most accurate in classifying NL and MCI; 2) both imaging modalities identified the temporal neocortex as best separating MCI and AD, whereas widespread changes accurately classified NL and AD; 3) In most between group comparisons regional MRglu measures were diagnostically superior to volume measures. These cross-sectional data show that in MCI hippocampal formation changes exist without significant neocortical changes. Neocortical changes best characterize AD. In both MCI and AD, metabolism reductions exceed volume losses.
- Published
- 2001
47. Cortisol Reduces Hippocampal Glucose Metabolism in Normal Elderly, but Not in Alzheimer’s Disease*
- Author
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Thomas McRae, Nora D. Volkow, Henry Rusinek, M. J. de Leon, James Golomb, Antonio Convit, S. De Santi, K. Daisley, Chaim Tarshish, N. Orentreich, and Bruce S. McEwen
- Subjects
Blood Glucose ,Male ,Aging ,medicine.medical_specialty ,Hydrocortisone ,Endocrinology, Diabetes and Metabolism ,Clinical Biochemistry ,Hippocampal formation ,Carbohydrate metabolism ,Hippocampus ,Biochemistry ,chemistry.chemical_compound ,Endocrinology ,Alzheimer Disease ,Fluorodeoxyglucose F18 ,Reference Values ,Corticosterone ,Internal medicine ,Humans ,Medicine ,Hippocampus (mythology) ,Aged ,business.industry ,Biochemistry (medical) ,Glucose transporter ,Brain ,Magnetic Resonance Imaging ,Glucose ,chemistry ,Female ,Animal studies ,Radiopharmaceuticals ,business ,Glucocorticoid ,Tomography, Emission-Computed ,medicine.drug - Abstract
Glucocorticoids are known to play a role in the regulation of peripheral glucose mobilization and metabolism. Although several animal studies have shown that hippocampal glucose metabolism is reduced acutely and chronically by the action of corticosterone and that excess glucocorticoids are harmful to hippocampal neurons, little is known about the central effects of glucocorticoids in the human. In this study we examined the brain glucose utilization (CMRglu) response to hydrocortisone (cortisol) in seven normal elderly and eight Alzheimer’s disease (AD) patients. On 2 separate days, immediately after the administration of a bolus of either 35 mg hydrocortisone or placebo, we administered 2-deoxy-2-[18F]fluoro-d-glucose. After a 35-min radiotracer uptake period, positron emission tomography (PET) images were collected. PET CMRglu images were analyzed using two methods: an image transformation that allowed analyses across cases on a voxel by voxel basis, and an anatomically based region of interest method that used coregistered magnetic resonance imaging scans. Both image analysis methods yielded similar results, identifying relative to placebo, a specific hippocampal CMRglu reduction in response to the hydrocortisone challenge that was restricted to the normal group. The region of interest technique showed CMRglu reductions of 16% and 12% in the right and left hippocampi, respectively. Blood collected during the PET scans showed, for the normal group, a rise in plasma glucose levels, starting approximately 25 min after hydrocortisone administration. The AD group did not show this effect. Baseline cortisol was elevated in the AD group, but the clearance of hydrocortisone was not different between the groups. In conclusion, these data show that among normal individuals in the presence of a pharmacological dose of cortisol, the glucose utilization of the hippocampus is specifically reduced, and serum glucose levels increase. Based in part on other studies, we offer the interpretation that glucocorticoid-mediated regulation of glucose transport is altered in AD, and this may underlie both the hippocampal insensitivity to cortisol and the failure in these patients to mount a peripheral glucose response. As our findings could reflect an altered state of the AD patients, we interpret our results as preliminary with respect to evidence for metabolic abnormalities in AD. The results suggest the continued study of the hydrocortisone challenge as a test of hippocampal responsivity.
- Published
- 1997
48. Specific Hippocampal Volume Reductions in Individuals at Risk for Alzheimer’s Disease
- Author
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S. De Santi, Chaim Tarshish, Henry Rusinek, M. J. de Leon, W. Tsui, Antonio Convit, and Ajax E. George
- Subjects
Male ,Risk ,Aging ,medicine.medical_specialty ,Psychometrics ,Hippocampus ,Audiology ,Temporal lobe ,Central nervous system disease ,Degenerative disease ,Atrophy ,Alzheimer Disease ,mental disorders ,Image Processing, Computer-Assisted ,medicine ,Humans ,Dementia ,Aged ,Observer Variation ,Fusiform gyrus ,General Neuroscience ,medicine.disease ,Magnetic Resonance Imaging ,Temporal Lobe ,nervous system ,Female ,Neurology (clinical) ,Geriatrics and Gerontology ,Alzheimer's disease ,Cognition Disorders ,Psychology ,Neuroscience ,Developmental Biology - Abstract
Our goal was to ascertain the involvement of the temporal lobe in the preclinical (not yet diagnosable) stages of dementia of the Alzheimer’s type (DAT) by using MRI-derived volumes. We assessed anatomical subdivisions of the temporal lobe on three groups of carefully screened age- and education-matched elderly individuals: 27 normal elderly (NL), 22 individuals with minimal cognitive impairment (MCI), who did not fulfill DAT criteria but were regarded at high risk for future DAT, and 27 DAT individuals. We found hippocampal volume reductions of 14% for the MCI and 22% for the DAT group compared to the NL group. Utilizing regression analyses and after accounting for gender, head size, age, generalized atrophy (CSF), and other temporal lobe subvolumes, the hippocampal volume separated NL from MCI individuals, correctly classifying 74%. For NL and MCI groups combined the hippocampal volume was the only temporal lobe subvolume related to delayed recall memory performance. When contrasting MCI and DAT individuals, the fusiform gyrus volume uniquely improved the ability of the hippocampal volume to separate MCI from DAT individuals from 74 to 80%. Our cross-sectional data suggest that, within the temporal lobe, specific hippocampal volume reductions separated the group at risk for DAT from the normal group. By the time impairments are sufficient to allow a diagnosis of DAT to be made, in addition to the medial temporal lobe volume reductions, the lateral temporal lobe is also showing volume reductions, most saliently involving the fusiform gyrus.
- Published
- 1997
49. Plasma IGF-1 and IGFBP-3 may be imprecise surrogates for breast concentrations: an analysis of healthy women
- Author
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Jo L. Freudenheim, Scott L. Spear, Kepher H. Makambi, Mary E. Platek, Bhaskar Kallakury, Lucile L. Adams-Campbell, David J. Perry, Raphael J. Convit, Ramona G. Dumitrescu, Adana A.M. Llanos, Peter G. Shields, Catalin Marian, and Theodore M. Brasky
- Subjects
Oncology ,Adult ,Cancer Research ,medicine.medical_specialty ,Cross-sectional study ,medicine.medical_treatment ,Mammaplasty ,Breast Neoplasms ,Reduction Mammoplasty ,Article ,Breast cancer ,Reference Values ,Risk Factors ,Internal medicine ,medicine ,Humans ,Insulin-Like Growth Factor I ,skin and connective tissue diseases ,Mammary Glands, Human ,business.industry ,Cancer ,Middle Aged ,medicine.disease ,Endocrinology ,Cross-Sectional Studies ,Insulin-Like Growth Factor Binding Protein 3 ,Health ,Multivariate Analysis ,Linear Models ,Biomarker (medicine) ,Female ,Analysis of variance ,business ,Hormone - Abstract
We investigated insulin-like growth factor (IGF)-1 and IGF binding protein (IGFBP)-3 concentrations in histologically normal breast tissues and assessed their association with plasma concentrations, and breast cancer risk factors. IGF-1 and IGFBP-3 were assessed in plasma and breast tissues of 90 women with no history of any cancer and undergoing reduction mammoplasty. Pearson correlations and ANOVAs were used to describe plasma-breast associations and biomarker differences by breast cancer risk factors, respectively. Multivariable regression models were used to determine associations between risk factors, and breast IGF-1 and IGFBP-3. The mean age of the study sample was 37.3 years, 58 % were white, and generally these women were obese (mean BMI = 30.8 kg/m2). We observed no plasma-breast correlation for IGF-1, IGFBP-3, or IGF-1/IGFBP-3 (r = −0.08, r = 0.14, and r = 0.03, respectively; p-values >0.05). Through age- and BMI-adjusted analysis, BMI and years of oral contraceptive (OC) use were inversely associated with breast IGF-1 (p-values = 0.02 and 0.003, respectively) and age was associated with breast IGFBP-3 (p = 0.01), while breast IGF-1/IGFBP-3 was higher in blacks than whites (1.08 vs. 0.68, p = 0.04) and associated with age and BMI (p-values = 0.03 and 0.002, respectively). In multivariable-adjusted models, some breast cancer risk factors studied herein explained 24, 10, and 15 % of the variation in breast IGF-1, IGFBP-3, and IGF-1/IGFBP-3, respectively. While reasons for the lack of plasma-breast hormone correlations in these cancer-free women are unknown, several factors were shown to be associated with breast concentrations. The lack of correlation between blood and tissue IGF-1 and IGFBP-3 suggests that studies of breast cancer risk assessing blood IGF-1 and IGFBP-3 may have important limitations in understanding their role in breast carcinogenesis.
- Published
- 2013
50. Three dimensional mapping of the creatine kinase enzyme reaction rate in muscles of the lower leg
- Author
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Parasoglou, Prodromos, Xia, Ding, Chang, Gregory, Convit, Antonio, and Regatte, Ravinder R.
- Subjects
Adult ,Male ,Leg ,Magnetic Resonance Spectroscopy ,Phosphorus ,Article ,Metabolic Flux Analysis ,Kinetics ,Imaging, Three-Dimensional ,Diabetes Mellitus, Type 2 ,Humans ,Computer Simulation ,Female ,Spin Labels ,Energy Metabolism ,Muscle, Skeletal ,Creatine Kinase - Abstract
Phosphorus ((31) P) magnetization transfer (MT) techniques enable the non-invasive measurement of metabolic turnover rates of important enzyme-catalyzed reactions, such as the creatine kinase reaction (CK), a major transducing reaction involving adenosine triphosphate and phosphocreatine. Alteration in the kinetics of the CK reaction rate appears to play a central role in many disease states. In this study, we developed and implemented at ultra-high field (7T) a novel three-dimensional (31) P-MT imaging sequence that maps the kinetics of CK in the entire volume of the lower leg at relatively high resolution (0.52 mL voxel size), and within acquisition times that can be tolerated by patients (below 60 min). We tested the sequence on five healthy and two clinically diagnosed type 2 diabetic subjects. Overall, we obtained measurements that are in close agreement with measurements reported previously using spectroscopic methods. Importantly, our spatially resolved method allowed us to measure local CK reaction rate constants and metabolic fluxes in individual muscles in a non-invasive manner. Furthermore, it allowed us to detect variations of the CK rates of different muscles, which would not have been possible using unlocalized MRS methods. The results of this work suggest that 3D mapping of the CK reaction rates and metabolic fluxes can be achieved in the skeletal muscle in vivo at relatively high spatial resolution and with acquisition times well tolerated by patients. The ability to measure bioenergetics simultaneously in large areas of muscles will bring new insights into possible heterogeneous patterns of muscle metabolism associated with several diseases and serve as a valuable tool for monitoring the efficacy of interventions.
- Published
- 2013
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