41 results on '"Davis PA"'
Search Results
2. Integrating yoga with psychological group-treatment for mixed depression and anxiety in primary healthcare: An explorative pilot study.
- Author
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Jonsson G, Franzén L, Nyström MBT, and Davis PA
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- Anxiety therapy, Depression therapy, Humans, Pilot Projects, Primary Health Care, Quality of Life, Yoga
- Abstract
Background and Purpose: Yoga has shown promise as a treatment for depression and anxiety. The present pilot study investigated the feasibility of an eight-week grouptreatment integrating emotion-focused psychoeducation, compassion-focused therapy, and Virya yoga for depression and anxiety in primary healthcare., Materials and Methods: Patients seeking treatment for depression and anxiety in a primary healthcare centre completed either an integrative group-treatment (N = 14) or treatment as usual (TAU, N = 17). Outcome measures were analysed pre- and posttreatment. Correlations in the intervention group were investigated between treatment outcomes and amount of yoga practice between sessions., Results: Large within-group effect sizes on all outcome measures were found at posttreatment. Symptom reduction did not differ between groups (p = 0.155). Improvement in alexithymia correlated significantly (p < 0.05) with amount of yoga practice between sessions., Conclusion: Integrating yoga with a psychological group-treatment is a somewhat feasible approach to treatment for depression and anxiety in primary healthcare., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2020
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3. Rho kinase inhibitors for SARS-CoV-2 induced acute respiratory distress syndrome: Support from Bartter's and Gitelman's syndrome patients.
- Author
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Calò LA, Bertoldi G, and Davis PA
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- Betacoronavirus, COVID-19, Humans, SARS-CoV-2, rho-Associated Kinases, Acute Lung Injury, Coronavirus Infections, Gitelman Syndrome, Pandemics, Pneumonia, Viral, Respiratory Distress Syndrome
- Abstract
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Published
- 2020
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4. Oxidative stress - chronic kidney disease - cardiovascular disease: A vicious circle.
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Ravarotto V, Simioni F, Pagnin E, Davis PA, and Calò LA
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- Disease Progression, Humans, Risk Factors, Cardiovascular Diseases etiology, Oxidative Stress, Renal Insufficiency, Chronic complications
- Abstract
Chronic kidney disease patient's progression to end-stage renal disease as well as their high mortality are linked to cardiovascular disease. However, the high incidence rate of cardiovascular morbidity and mortality in these patients is not fully accounted for by traditional cardiovascular risk factors such as diabetes, hypertension and obesity. Renal disease and CVD are associated with endothelial dysfunction, inflammation and oxidative stress and in this review we will examine what is known regarding their similar roles in both CVD and chronic kidney disease, specifically focusing on the interconnections between oxidative stress, inflammation and endothelial dysfunction. These interconnections are best visualized as a vicious circle wherein these entities coexist and communicate with each other, thereby exacerbating the processes underpinning these different entities with the end result of the high morbidity and mortality that characterize CKD patients. By exploring this vicious circle i.e. the mode and extent of the interrelationships as well as some of the underlying mechanisms involved, this review aims at outlining our current understanding as well as highlighting future avenues for research and potential targets for therapeutic intervention., (Copyright © 2018 Elsevier Inc. All rights reserved.)
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- 2018
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5. Uric acid and cardiovascular-renal disease risk. Insights from a human model opposite to hypertension.
- Author
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Maiolino G, Pagnin E, Plebani M, Davis PA, and Calò LA
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- Adolescent, Adult, Aged, Biomarkers blood, Cardiovascular Diseases diagnosis, Cohort Studies, Female, Humans, Hypertension diagnosis, Kidney Diseases diagnosis, Male, Middle Aged, Risk Factors, Young Adult, Cardiovascular Diseases blood, Hypertension blood, Kidney Diseases blood, Uric Acid blood
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- 2016
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6. Increased rho kinase activity in mononuclear cells of dialysis and stage 3-4 chronic kidney disease patients with left ventricular hypertrophy: Cardiovascular risk implications.
- Author
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Calò LA, Vertolli U, Pagnin E, Ravarotto V, Davis PA, Lupia M, Naso E, Maiolino G, and Naso A
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- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine analogs & derivatives, 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine pharmacology, Adult, Aged, Enzyme Activation drug effects, Enzyme Activation physiology, Female, Humans, Hypertrophy, Left Ventricular diagnosis, Hypertrophy, Left Ventricular epidemiology, Leukocytes, Mononuclear drug effects, Male, Middle Aged, Protein Kinase Inhibitors pharmacology, Renal Dialysis adverse effects, Renal Insufficiency, Chronic diagnosis, Renal Insufficiency, Chronic epidemiology, Risk Factors, Hypertrophy, Left Ventricular enzymology, Leukocytes, Mononuclear enzymology, Renal Dialysis trends, Renal Insufficiency, Chronic enzymology, rho-Associated Kinases metabolism
- Abstract
Aims: Cardiovascular disease (CVD) is the leading cause of excess mortality in chronic kidney disease (CKD) and dialysis patients (DP) who have higher prevalence of left ventricular hypertrophy (LVH), the strongest predictor of CV events. Rho kinase (ROCK) activation is linked in hypertensive patients to cardiac remodeling while ROCK inhibition suppresses cardiomyocyte hypertrophy and, in a human clinical condition opposite to hypertension, its downregulation associates with lack of CV remodeling. Information on ROCK activation-LVH link in CKD and DP is lacking., Materials and Methods: Mononuclear cells (PBMCs) MYPT-1 phosphorylation, a marker of ROCK activity, and the effect of fasudil, a ROCK inhibitor, on MYPT-1 phosphorylation were assessed in 23 DPs, 13 stage 3-4 CKD and 36 healthy subjects (HS) by Western blot. LV mass was assessed by M-mode echocardiography., Key Findings: DP and CKD had higher MYPT-1 phosphorylation compared to HS (p<0.001 and p=0.003). Fasudil (500 and 1000μM) dose dependently reduced MYPT-1 phosphorylation in DP (p<0.01). DP had higher LV mass than CKD (p<0.001). MYPT-1 phosphorylation was higher in patients with LVH (p=0.009) and correlated with LV mass both in DP and CKD with LVH (p<0.001 and p=0.006)., Significance: In DP and CKD, ROCK activity tracks with LVH. This ROCK activation-LVH link provided in these CVD high-risk patients along with similar findings in hypertensive patients and added to opposite findings in a human model opposite to hypertension and in type 2 diabetic patients, identify ROCK activation as a potential LVH marker and provide further rationale for ROCK activation inhibition as target of therapy in CVD high-risk patients., (Copyright © 2016 Elsevier Inc. All rights reserved.)
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- 2016
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7. Molecular biology based assessment of green tea effects on oxidative stress and cardiac remodelling in dialysis patients.
- Author
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Calo LA, Vertolli U, Davis PA, Maso LD, Pagnin E, Ravarotto V, Maiolino G, Lupia M, Seccia TM, and Rossi GP
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- Adult, Aged, Antioxidants pharmacology, Cardiovascular Diseases etiology, Female, Heme Oxygenase-1 metabolism, Humans, Kidney Failure, Chronic complications, Lipoproteins, LDL blood, MAP Kinase Signaling System, Male, Middle Aged, Phosphorylation, Risk Factors, Ventricular Function, Left drug effects, Cardiovascular Diseases prevention & control, Heart drug effects, Kidney Failure, Chronic drug therapy, Oxidative Stress drug effects, Plant Extracts pharmacology, Tea chemistry
- Abstract
Background & Aims: Cardiovascular disease, the most common cause for morbidity and mortality in end-stage renal disease (ESRD), has prompted the exploration of multiple approaches to improve outcomes. Cardiovascular risk factors such as oxidative stress (OxSt) and cardiac remodelling are common in ESRD and dialysis patients. Green tea (GT) is well recognized as reducing OxSt. This 6 months study evaluated in 20 ESRD patients under chronic dialysis, the effect of GT treatment (1 g/day as commercially available capsule) on cellular and plasma OxSt and proliferation related markers using a molecular biology approach., Methods: Mononuclear cell p22(phox), Haeme Oxygenase (HO)-1 protein expression, and phosphorylated ERK1/2 status were evaluated in dialysis patients at baseline, after 3 and 6 months of GT treatment by Western blot analysis and plasma oxLDL by ELISA. Cardiac remodelling was assessed by echocardiographic left ventricular (LV) mass determination at baseline and at the end of the study., Results: GT treatment reduced p22(phox) and pERK1/2 from baseline while HO-1 increased. At baseline, LV mass correlated with both p22(phox) and oxLDL. GT treatment decreased LV mass from baseline, which correlated with oxLDL. 9 patients had LV hypertrophy at baseline, which, at 6 months, was normalized in 5 and reduced in 3, showing a parallel decrease of p22(phox), pERK1/2, oxLDL and increase of HO-1., Conclusions: Treatment with GT decreased the expression of OxSt-related proteins tightly associated with cardiovascular disease and decreased LV mass. It appears highly likely that the addition of GT can provide a benefit in terms of cardiovascular protection in dialysis patients., (Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.)
- Published
- 2014
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8. Modulation of skin oxidative stress and inflammatory markers by environmental stressors. Differences between young and old.
- Author
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Sticozzi C, Pecorelli A, Lim Y, Maioli E, Pagnin E, Davis PA, and Valacchi G
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- Aging pathology, Aldehydes metabolism, Animals, Biomarkers metabolism, Heme Oxygenase-1 metabolism, Interleukin-6 metabolism, Interleukin-8 metabolism, Mice, Mice, Inbred Strains, Models, Animal, NADPH Oxidases metabolism, Skin pathology, Skin physiopathology, Aging metabolism, Inflammation physiopathology, Oxidative Stress physiology, Ozone adverse effects, Skin metabolism, Smoking adverse effects
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- 2012
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9. Cigarette smoke exposure causes changes in Scavenger Receptor B1 level and distribution in lung cells.
- Author
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Valacchi G, Davis PA, Khan EM, Lanir R, Maioli E, Pecorelli A, Cross CE, and Goldkorn T
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- Animals, Cell Line, Tumor, Cell Membrane metabolism, Humans, Immunohistochemistry, Lung cytology, Mice, Microscopy, Confocal, RNA, Messenger genetics, RNA, Messenger metabolism, Time Factors, Biological Transport drug effects, Lung Neoplasms etiology, Scavenger Receptors, Class B genetics, Scavenger Receptors, Class B metabolism, Smoking adverse effects, Tocopherols metabolism, Ubiquitination drug effects
- Abstract
Scavenger Receptor B1 has been shown to play a prominent role in the uptake and delivery of vitamin E from HDL and is likely involved in regulating vitamin E in the lung. We have previously demonstrated that lung Scavenger Receptor B1 levels (protein and mRNA) are modulated by cigarette smoke in mice and this was accompanied by changes in lung vitamin E. To further characterize the molecular mechanism(s) involved in this process, human alveolar epithelial cells were exposed to cigarette smoke and Scavenger Receptor B1 cellular levels and distribution were assessed. Results demonstrated that Scavenger Receptor B1 localizes in patches on the cellular membrane and in the per nuclear area of control cells. Upon cigarette smoke exposure, Scavenger Receptor B1 first translocated to the cell surface (within the first 12h of exposure) and then cell levels (protein and mRNA levels) decreased significantly at 24h. This decline was accompanied by increased Scavenger Receptor B1 ubiquitination which may explain the decrease in the protein levels. Cigarette smoke induced changes in both sub-cellular redistribution and ubiquitination of Scavenger Receptor B1 together with our previous in vivo data provides evidence that cigarette smoke exposure may alter lung's ability to control its tocopherol levels., (Copyright © 2009 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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10. Tree nut and peanut consumption in relation to chronic and metabolic diseases including allergy.
- Author
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Davis PA, Jenab M, Vanden Heuvel JP, Furlong T, and Taylor S
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- Animals, Cardiovascular Diseases prevention & control, Glucose Intolerance prevention & control, Humans, Inflammation prevention & control, Risk Factors, Arachis, Metabolic Diseases prevention & control, Neoplasms prevention & control, Nut Hypersensitivity, Nuts
- Abstract
The New and Emerging Research session highlighted the emerging understanding of both the positive and negative effects of nuts consumption on health. The limited nature of both experimental and epidemiological evidence for positive relationship(s) between nut intake and health were noted. Study inconsistency and limitations, particularly survey methodology, were explored. Recent results from epidemiologic studies indicating a potential negative association between nut and seed intake and cancer risk were reviewed. The ability of walnuts to reduce endothelin suggests an interesting biochemical mechanism of nut action that may affect other endothelin-associated diseases, which should be further explored. The effects of nuts and their constituents on a nuclear receptor screen (PPARalpha, beta/delta, gamma, LXRalpha, beta, RXRalpha, beta, gamma, PXR, and FXR) have been explored. Nut allergenicity and approaches necessary to minimize this effect were also described. In contrast to the positive effects, nut allergies present tree nut-allergic consumers with health challenges. The Food Allergy and Anaphylaxis Network stressed the importance of ensuring that consumers with food allergies have legible, accurate food labels. The Food Allergen Labeling and Consumer Protection Act has engendered precautionary, worst-case allergen scenario labeling statements with unknown benefits to consumer health. Issues of cross-contamination due to shared equipment and shared facilities highlighted the need to rely on allergen control programs that use ELISA technology and have increased understanding of nut allergens. Ultimately, to maximize the positive benefits of nuts, the consumer must be provided with all the information required to make an informed choice.
- Published
- 2008
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11. Antioxidant effect of L-carnitine and its short chain esters: relevance for the protection from oxidative stress related cardiovascular damage.
- Author
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Calò LA, Pagnin E, Davis PA, Semplicini A, Nicolai R, Calvani M, and Pessina AC
- Subjects
- Apoptosis, Cardiovascular Diseases physiopathology, Cell Culture Techniques, Endothelial Cells drug effects, Endothelium drug effects, Gene Expression drug effects, Heme Oxygenase-1 drug effects, Heme Oxygenase-1 genetics, Humans, Nitric Oxide Synthase drug effects, Nitric Oxide Synthase genetics, Oxidative Stress drug effects, Oxidative Stress genetics, Reactive Oxygen Species, Umbilical Cord, Cardiovascular Diseases complications, Carnitine pharmacology, Endothelium injuries, Oxidative Stress physiology
- Abstract
Background: Increased oxidative stress is associated with all cardiovascular risk factors and reactive oxygen species appear to be the principal mediators of cardiomyocite dysfunction in various cardiovascular diseases. Carnitine has been shown to be effective in pathologic conditions characterized by increased oxidative stress and an antioxidant effect of L-carnitine and its derivatives has been described but the specific mechanism is unclear., Methods: We evaluated in human endothelial cells in culture the effect of L-carnitine (C), acetyl-L-carnitine (AC) and propionyl-L-carnitine (PC) on gene and protein expression (RT-PCR and Western blot) of oxidative stress related proteins heme oxygenase-1 (HO-1) and of endothelial NO synthase (ecNOS) in absence and presence of oxidative stress induced by H2O2., Results: HO-1 as well as ecNOS gene and protein expression significantly increased upon Carnitines incubation. Induction of oxidative stress increased HO-1 gene expression compared to basal condition (0.62+/-0.02 densitometric units vs. 0.48+/-0.05, p<0.01) while decreased ecNOS gene expression (0.75+/-0.04 vs. 0.40+/-0.08, p<0.001). These results were paralleled by similar results at protein level. Coincubation of C (0.5-1.0-2.0 mM), AC (0.1-0.2-0.4 mM) and PC (0.05-0.1-0.2 mM) with H2O2 further increased HO-1 gene expression and not only normalized vs. H2O2 but even increased vs. basal ecNOS mRNA. HO-1 and ecNOS gene expression was also paralleled at protein level by coincubation with C, AC and PC of cells exposed to oxidative stress., Conclusion: This is the first report that has utilized a molecular biological approach to demonstrate a direct stimulatory effect of Carnitines on gene and protein expression of the oxidative stress related markers HO-1 and ecNOS. As HO-1 and NO are known as antioxidant, antiproliferative and anti-inflammatory, their increased expression would be expected to protect from oxidative stress related cardiovascular risk factors and myocardial damage, therefore adding this effect to the multiple pathways involved in the effects of carnitines.
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- 2006
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12. Modulation of cutaneous wound healing by ozone: differences between young and aged mice.
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Lim Y, Phung AD, Corbacho AM, Aung HH, Maioli E, Reznick AZ, Cross CE, Davis PA, and Valacchi G
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- Aldehydes analysis, Aldehydes chemistry, Animals, Cross-Linking Reagents analysis, Cross-Linking Reagents chemistry, Female, I-kappa B Proteins biosynthesis, Lipid Peroxidation drug effects, Mice, Mice, Hairless, Models, Animal, NF-KappaB Inhibitor alpha, Protein Binding, Proteins analysis, Proteins chemistry, Skin injuries, Skin metabolism, Transforming Growth Factor beta biosynthesis, Aging physiology, Ozone toxicity, Skin drug effects, Wound Healing drug effects
- Abstract
Cutaneous tissues are frequently exposed to prooxidative environments, including UV radiation and air pollutants. Among the latter, ozone (O(3)) is of particular concern because of its high and dominating presence in photochemical smog. It is well known that O(3) depletes small molecular weight antioxidants, oxidizes proteins, induces lipid peroxidation and activates cellular responses in various tissues. Using an in vivo model (SKH-1 hairless mice), the interaction between O(3) exposure (0.5ppmx6h/day) and age was examined in relation to cutaneous wound healing. Compared to younger (8 weeks) mice, older (18 months) mice exposed to O(3) (day 0 to day 9 after wounding) exhibited delayed wound closure, increased lipid peroxidation (measured as 4-HNE protein adducts) and protein oxidation (measured as carbonyls concentration) and decreased levels of P-IkappaBalpha and TGFbeta protein. These findings support the hypothesis that oxidant pollutant exposure and age interact so as to disrupt normal wound healing processes.
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- 2006
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13. Interaction of fat availability and sex on postprandial satiety and cholecystokinin after mixed-food meals.
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Burton-Freeman B, Davis PA, and Schneeman BO
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- Adult, Biological Availability, Cholecystokinin blood, Dietary Fats administration & dosage, Dietary Fats pharmacokinetics, Female, Humans, Male, Pain Measurement, Plant Oils, Prunus, Safflower Oil, Sex Distribution, Cholecystokinin physiology, Diet, Dietary Fats pharmacology, Satiation drug effects
- Abstract
Background: Cholecystokinin (CCK) is associated with fat-induced satiety., Objective: The primary objective of the present study was to determine, in an acute meal setting, whether the availability of dietary fat for alimentary processing, and hence the stimulation of CCK, affects the postmeal satiety response in men and women., Design: In a within-subjects design, subjects (8 men, 7 women) consumed 1 of 3 isoenergetic mixed-food test meals 1 wk apart in random order. The test meals contained 30% of energy from fat, of which more than two-thirds was derived from whole almonds, almond oil, or a mix of safflower and corn oils. Visual analogue scales were used to assess indexes of satiety at defined time points up to 6 h after meal consumption. Blood was sampled at corresponding time points for measurement of CCK, glucose, insulin, and triacylglycerol. Subsequent food intake was also assessed., Results: All meals suppressed hunger and induced a pattern of satiety that was sex-specific and corresponded with the CCK response. Women had higher plasma CCK concentrations and experienced greater satiety after the almond oil and control meals (fat as oil) than after the whole almond meal (fat in whole food structure). Men showed no differential response among meals for CCK and satiety. Plasma triacylglycerol differed by time among meals but not by sex, and no significant differences in glucose and insulin were found., Conclusions: The satiety response to dietary fat provided in oil or whole food form is influenced by sex and is dependent on the availability of fat to stimulate CCK release in women but not in men.
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- 2004
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14. Induction of stress proteins and MMP-9 by 0.8 ppm of ozone in murine skin.
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Valacchi G, Pagnin E, Okamoto T, Corbacho AM, Olano E, Davis PA, van der Vliet A, Packer L, and Cross CE
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- Animals, Heme Oxygenase (Decyclizing) biosynthesis, Heme Oxygenase (Decyclizing) genetics, Heme Oxygenase-1, Kinetics, Lipid Peroxidation, Matrix Metalloproteinase 9 genetics, Membrane Proteins, Mice, Molecular Chaperones, Neoplasm Proteins biosynthesis, Neoplasm Proteins genetics, RNA, Messenger biosynthesis, Skin enzymology, Skin metabolism, Up-Regulation, Heat-Shock Proteins, Matrix Metalloproteinase 9 biosynthesis, Oxidants, Photochemical pharmacology, Oxidative Stress, Ozone pharmacology, Skin drug effects
- Abstract
Ozone (O(3)) is among the most reactive environmental oxidant pollutants to which cutaneous tissues are exposed. O(3) exposure has been shown to induce antioxidant depletion as well as the oxidation of lipids and proteins within the outermost skin layer, the stratum corneum. However, relatively little is known regarding the potential effects of O(3) on the cellular constituents of the underlying skin epidermis and dermis. In the present study, hairless mice exposed for 6 h to 0.8 ppm O(3) showed increases in lipid peroxidation, as quantitated by increases in 4-hydroxynonenal-protein adducts. O(3) exposure caused an induction of the stress proteins HSP27 and heme oxygenase-1 (HO-1), starting at 6 h and increasing up to 18 h after O(3) exposure. This was accompanied by an increase in matrix metalloproteinase-9 (MMP-9) mRNA and activity levels, indicative of possible injurious-reparative processes. Collectively, our data demonstrate that skin exposure to O(3) not only affects antioxidant levels and oxidation markers in the outermost stratum corneum layer, but also induces cellular stress responses in the deeper cellular layers of the skin.
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- 2003
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15. What influences a woman to choose vaginal birth after cesarean?
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Ridley RT, Davis PA, Bright JH, and Sinclair D
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- Adult, Cesarean Section trends, Female, Humans, Internal-External Control, Obstetric Nursing, Physician-Patient Relations, Pregnancy, Self Efficacy, Social Support, Southeastern United States, Decision Making, Health Knowledge, Attitudes, Practice, Vaginal Birth after Cesarean nursing
- Abstract
Objective: To discover what influences women in the decision to deliver via vaginal birth after cesarean (VBAC)., Design: Descriptive and qualitative, influenced by principles of phenomenology and using content analysis to describe the lived experiences of women who choose VBAC., Setting: Women were recruited from a postpartum unit in a hospital in the rural southeastern United States., Participants: Five women who had delivered via VBAC within 2 to 4 months before the study., Results: The major influences that affect a woman's decision to choose VBAC are described. The dominant themes found were the woman's sense of control in the decision-making process; physician encouragement for VBAC; and delivery type outcome advantages, incorporating physical and emotional factors., Conclusion: Women are influenced by internal and external factors in their decision to choose VBAC. Their choices come from their personal experiences and should be encouraged by health care providers during all aspects of the childbearing process.
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- 2002
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16. Plasma cholecystokinin is associated with subjective measures of satiety in women.
- Author
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Burton-Freeman B, Davis PA, and Schneeman BO
- Subjects
- Adult, Blood Glucose metabolism, Cross-Over Studies, Diet Records, Dietary Fats administration & dosage, Dietary Fiber administration & dosage, Eating, Energy Intake, Fasting, Female, Food, Humans, Insulin blood, Kinetics, Male, Middle Aged, Sex Characteristics, Triglycerides blood, Cholecystokinin blood, Satiation physiology
- Abstract
Background: Cholecystokinin is associated with satiety. Fat stimulates cholecystokinin release, and fiber appears to prolong cholecystokinin elevation during the alimentary period., Objective: We tested whether adding fiber or fat to a low-fat, low-fiber meal increases cholecystokinin release and enhances subjective measures of satiety and whether the cholecystokinin response correlates with subjective measures of satiety., Design: Three isoenergetic breakfast meals were tested in a randomized crossover design: low fiber, low fat; high fiber, low fat; and low fiber, high fat. Blood samples were drawn from fasted subjects (7 men and 8 women) before and at different time points after test meal consumption for 6 h. Plasma was analyzed for cholecystokinin, insulin, glucose, and triacylglycerols. Visual analogue scales were used to assess subjects' hunger, desire to eat, fullness, and prospective consumption., Results: In the women, the meals higher in fiber or in fat resulted in greater feelings of satiety and in significantly higher cholecystokinin responses than did the low-fat, low-fiber meal. In the men, the increase in cholecystokinin concentration did not differ between meals, but the 2 low-fat meals elicited a greater feeling of satiety than did the high-fat meal. The insulin response was significantly higher for the low-fiber, low-fat meal than for the other 2 meals, and the triacylglycerol response was greatest for the high-fat, low-fiber meal., Conclusion: In women, the feeling of satiety caused by cholecystokinin release is enhanced by increasing either the fiber or fat content of a low-fat, low-fiber meal.
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- 2002
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17. Almonds and almond oil have similar effects on plasma lipids and LDL oxidation in healthy men and women.
- Author
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Hyson DA, Schneeman BO, and Davis PA
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- Adult, Cardiovascular Diseases prevention & control, Cholesterol, LDL blood, Cross-Over Studies, Energy Intake, Fatty Acids, Monounsaturated administration & dosage, Female, Humans, Male, Oxidation-Reduction drug effects, Fatty Acids, Monounsaturated pharmacology, Lipids blood, Nuts, Plant Oils pharmacology
- Abstract
Epidemiologic and clinical studies have shown that nut consumption is associated with favorable plasma lipid profiles and reduced cardiovascular risk. These effects may result from their high monounsaturated fat (MUFA) content but nuts contain constituents other than fatty acids that might be cardioprotective. We conducted a study to compare the effects of whole-almond vs. almond oil consumption on plasma lipids and LDL oxidation in healthy men and women. Using a randomized crossover trial design, 22 normolipemic men and women replaced half of their habitual fat (approximately 14% of approximately 29% energy) with either whole almonds (WA) or almond oil (AO) for 6-wk periods. Compliance was ascertained by monitoring dietary intake via biweekly 5-d food records, return of empty almond product packages and weekly meetings with a registered dietitian. Fat replacement with either WA and AO resulted in a 54% increase in percentage of energy as MUFA with declines in both saturated fat and cholesterol intake and no significant changes in total energy, total or polyunsaturated fat intake. The effects of WA and AO on plasma lipids did not differ compared with baseline; plasma triglyceride, total and LDL cholesterol significantly decreased, 14, 4 and 6% respectively, whereas HDL cholesterol increased 6%. Neither treatment affected in vitro LDL oxidizability. We conclude that WA and AO do not differ in their beneficial effects on the plasma lipid variables measured and that this suggests that the favorable effect of almonds is mediated by components in the oil fraction of these nuts.
- Published
- 2002
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18. Reduced content of alpha subunit of Gq protein content in monocytes of Bartter and Gitelman syndromes: relationship with vascular hyporeactivity.
- Author
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Calò L, Davis PA, and Semplicini A
- Subjects
- Bartter Syndrome immunology, GTP-Binding Protein alpha Subunits, Gq-G11, Humans, Hypotension immunology, Bartter Syndrome metabolism, Heterotrimeric GTP-Binding Proteins metabolism, Hypotension metabolism, Monocytes metabolism
- Published
- 2002
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19. Abnormalities of Gq-mediated cell signaling in Bartter and Gitelman syndromes.
- Author
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Calò L, Ceolotto G, Milani M, Pagnin E, van den Heuvel LP, Sartori M, Davis PA, Costa R, and Semplicini A
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- Adult, Bartter Syndrome blood, Calcium metabolism, Enzyme Activation, Female, GTP-Binding Protein alpha Subunits, Gq-G11, Heterotrimeric GTP-Binding Proteins biosynthesis, Humans, Inositol Phosphates metabolism, Isoenzymes analysis, Isoenzymes metabolism, Male, Middle Aged, Nitric Oxide Synthase biosynthesis, Nitric Oxide Synthase Type III, Protein Kinase C analysis, Protein Kinase C metabolism, Signal Transduction, Syndrome, Bartter Syndrome metabolism, Heterotrimeric GTP-Binding Proteins metabolism
- Abstract
Background: The constitutive endothelial isoform of nitric oxide synthase (ecNOS) and nitric oxide (NO) production are increased in patients with Bartter syndrome (BS) and Gitelman (GS) syndrome and may reduce vascular tone. Moreover, these patients present an abnormal cell signaling [reduced stimulated intracellular calcium ([Ca(2+)](i)) and inositol-1,4,5,triphosphate ([IP(3)](i)) in neutrophils], suggesting the presence of a generalized reduction of protein kinase C (PKC) and cell reactivity. Since PKC regulates ecNOS gene expression, we evaluated the signal transduction system involving Gq protein, PKC, and ecNOS in circulating nucleated cells from patients with BS/GS., Methods: Nucleated blood cells from 2 BS and 7 GS and from 10 controls (C) were used. PKC activity was evaluated in neutrophils by radioenzymatic assay; PKC alpha concentration was evaluated in monocytes by Western blot analysis. ecNOS and G alpha q mRNA production was evaluated in monocytes by reverse transcription-polymerase chain reaction (RT-PCR) analysis using specific primers and quantitated by PCR-based semiquantitative analysis of ecNOS and G alpha q mRNA expression., Results: Cytosol and membrane basal PKC activity were similar in neutrophils from BS/GS and C (70 +/- 3 vs. 80 +/- 2; 37 +/- 3 vs. 46 +/- 2 pmol/min/mg protein, respectively), while fMLP-stimulated membrane PKC activity increased to a lower extent in BS/GS (from 43 +/- 2 to 53 +/- 3 vs. 38 +/- 2 to 66 +/- 3 pmol/min/mg protein, P < 0.05 for the difference). Membrane PKC alpha expression was similar in basal conditions (8.5 +/- 1.5 vs. 12.4 +/- 4.0 densitometric units), but increased after fMLP was reduced in BS/GS (4.5 +/- 1.4 vs. 9.5 +/- 2.1, P < 0.01). In BS/GS, PKC stimulation with PMA dose dependently reduced ecNOS gene expression (from 0.80 +/- 0.05 to 0.78 +/- 0.03 densitometric units; PMA 50 nmol/L, P = NS; to 0.55 +/- 0.07, PMA 100 nmol/L, P < 0.001) to an undetectable expression (PMA 200 nmol/L). Qualitatively similar effects were seen in monocytes from control subjects. Incubation of monocytes from patients and controls with the PKC inhibitor GF109203X increased ecNOS mRNA, with no difference between patients and controls. G alpha q mRNA was reduced in BS/GS versus controls (0.87 +/- 0.013 vs. 0.98 +/- 0.005 densitometric units, P < 0.0004)., Conclusion: An abnormal G alpha q expression blunts cell signaling and PKC production in BS/GS. A reduced PKC up-regulated NO system may contribute to the vascular hyporeactivity of BS/GS.
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- 2001
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20. Beans, as a source of dietary fiber, increase cholecystokinin and apolipoprotein b48 response to test meals in men.
- Author
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Bourdon I, Olson B, Backus R, Richter BD, Davis PA, and Schneeman BO
- Subjects
- Adult, Analysis of Variance, Apolipoprotein B-48, Body Mass Index, Cross-Over Studies, Dietary Fiber administration & dosage, Humans, Insulin blood, Male, Middle Aged, Postprandial Period, Triglycerides blood, Apolipoproteins B blood, Blood Glucose drug effects, Cholecystokinin blood, Dietary Fiber pharmacology, Fabaceae, Plants, Medicinal
- Abstract
Dry beans lower plasma cholesterol, an effect that has been associated with both the fiber and the protein content of beans. The objective of this study was to determine the acute hormone and lipid responses to a test meal that contained dry beans as a source of dietary fiber. A crossover design was employed in which men consumed the test meal and a control meal in random order. Both meals contained egg, bread, jelly, orange juice, milk and margarine. The high fiber meal contained white beans, whereas the low fiber (control) meal contained rice and dry milk. The men maintained their normal dietary pattern and fasted overnight before the study days. After a fasting blood sample was drawn, the men consumed the test meal and blood samples were collected over the next 6 h. Blood samples were analyzed for cholecystokinin (CCK), insulin and glucose. Plasma was separated into lipoprotein fractions and the triglyceride, cholesterol, apolipoprotein (apo) B100 and B48 content of triglyceride-rich lipoproteins determined. Insulin and glucose responses did not differ significantly between test meals; however, the CCK response was twice as high after the bean-containing meal than after the low fiber meal (P = 0.03). The increase in apo B48 concentration was significantly higher after the bean meal than after the low fiber meal (P < 0.05). Adding beans to a meal to increase fiber content prolongs the postprandial presence of intestinally derived lipoproteins and augments the CCK response to the meal.
- Published
- 2001
- Full Text
- View/download PDF
21. High-performance liquid chromatography multiplex detection of two single nucleotide mutations associated with hereditary hemochromatosis.
- Author
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Liang Q, Davis PA, Thompson BH, and Simpson JT
- Subjects
- DNA blood, DNA chemistry, DNA, Complementary chemistry, Genotype, Hemochromatosis blood, Hemochromatosis Protein, Humans, Nucleotides analysis, Polymerase Chain Reaction, Polymorphism, Restriction Fragment Length, Chromatography, High Pressure Liquid methods, HLA Antigens genetics, Hemochromatosis genetics, Histocompatibility Antigens Class I genetics, Membrane Proteins, Mutation
- Abstract
High-performance liquid chromatography (HPLC) has been applied to the multiplex detection of the two single nucleotide mutations commonly found in hereditary hemochromatosis (HH). HH is associated with a major G to A transition at position 845 (mutation Cys282Tyr) and a minor C to G transition at position 187 (mutation His63Asp) in the cDNA of the HFE gene. Two detection assays were developed based on HPLC analysis of restriction fragment length polymorphism (RFLP) or single nucleotide extension (SNE) products following multiplex PCR amplification. RFLP genotypes the two sites as dsDNA fragments of different lengths generated by restriction enzymes Rsa I/Bcl I. SNE extends primers 5'-adjacent to the sites of interest with a dideoxynucleotide triphosphate (ddNTP) to generate extended ssDNA. The identity of the added ddNTP reveals the identity of the original possible mutation site(s). Application of these methods with HPLC analysis provides simple and reliable genotyping for HH and can be applied to other single nucleotide polymorphism studies.
- Published
- 2001
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- View/download PDF
22. Optimization of intercalation dye concentration for short tandem repeat allele genotyping using capillary electrophoresis with laser-induced fluorescence detection.
- Author
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Marino MA, Devaney JM, Davis PA, and Girard JE
- Subjects
- Alleles, Genotype, Lasers, Reference Standards, Tandem Repeat Sequences genetics, Benzoxazoles analysis, DNA analysis, Electrophoresis, Capillary methods, Intercalating Agents analysis, Quinolinium Compounds analysis, Spectrometry, Fluorescence methods
- Abstract
DNA analysis using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection requires that polymerase chain reaction products either be prepared using primers with fluorescent molecules covalently bonded to them, or stained with a fluorescent intercalation dye following amplification. The intercalation technique has the advantage of allowing fluorescence detection of any double-stranded DNA (dsDNA) product regardless of the amplification primers used. The increased sensitivity of LIF detection is sometimes compromised by the intercalation dye changing the mass to charge ratio of the DNA. The purpose of this study was to evaluate the changes of migration rate, resolution and fluorescent intensity of dye-DNA complexes during electrophoretic separations, and to establish the optimal parameters for short tandem repeats alleles profiling. The alleles of three STR loci THO1, F13A01 and vWFA31 were intercalated with the monomeric dyes TOPRO-1 and YOPRO-1, and their corresponding dimers, TOTO-1 and YOYO-1 (Molecular Probes, Eugene, OR, USA). Alleles intercalated before injection onto the CE column resulted in loss of resolution and sensitivity when compared to the on-column labeling technique. The results of this experimentation were then applied to a STR typing assay using a commercially available polymer and buffer matrix. This assay included development of a unique internal standard used for migration time normalization assignment of alleles. Consequently, the 9 allele and the 9.3 microvariant of the THOI locus were separated and typed correctly with a resolution of 0.49 in less than 20 min, and the only sample preparation necessary after amplification was a dilution step.
- Published
- 1999
- Full Text
- View/download PDF
23. (n-3) fatty acid supplementation in moderately hypertriglyceridemic adults changes postprandial lipid and apolipoprotein B responses to a standardized test meal.
- Author
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Tinker LF, Parks EJ, Behr SR, Schneeman BO, and Davis PA
- Subjects
- Adult, Aged, Cross-Over Studies, Fasting, Female, Humans, Male, Middle Aged, Time Factors, Apolipoproteins B blood, Dietary Supplements, Eating physiology, Fatty Acids, Omega-3 therapeutic use, Hypertriglyceridemia blood, Lipids blood
- Abstract
The effects of (n-3) fatty acids on the postprandial state were investigated by monitoring the alimentary responses to identical test meals fed to adults [n = 11; fasting triacylglycerol (TG) 2.55 +/- 0.24 mmol/L; mean +/- SEM] after a self-selected diet baseline period (BLP) and then after a 6-wk (n-3) fatty acid period (FOP) [ approximately 5.2 g (n-3) fatty acids] and a 6-wk control oil period (COP) administered in random order. Samples were drawn immediately prior to the test meal (time 0) and then hourly from 2 to 6 h postmeal. Postprandial plasma triacylglycerol (TG) and TG-rich lipoprotein (TRL) TG apo B48, and B100 absolute concentrations were significantly lower after FOP than after COP or BLP, while plasma cholesterol was unchanged. Normalizing the results as increments over time 0 eliminated the diet effect on all but plasma TG. Time remained a significant effect for plasma TG, TRL TG, and TRL TC. Finally, only absolute TRL B48 and absolute and incremental plasma TG concentrations displayed significant time-diet interactions. These results suggest that postprandial TRL apo B reductions are likely caused by (n-3) fatty acid suppression of both hepatic and intestinal apoB secretion/synthesis. Altered TRL metabolism, i.e. changes in postprandial TG, cholesterol, apo B48, and increase in LDL particle size, may represent an additional mechanism for the reduced heart disease risk associated with fish [(n-3) fatty acid] consumption.
- Published
- 1999
- Full Text
- View/download PDF
24. Apple juice inhibits human low density lipoprotein oxidation.
- Author
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Pearson DA, Tan CH, German JB, Davis PA, and Gershwin ME
- Subjects
- Oxidation-Reduction, Regression Analysis, Antioxidants pharmacology, Beverages, Lipoproteins, LDL metabolism, Phenols pharmacology, Rosales
- Abstract
Dietary phenolic compounds, ubiquitous in vegetables and fruits and their juices possess antioxidant activity that may have beneficial effects on human health. The phenolic composition of six commercial apple juices, and of the peel (RP), flesh (RF) and whole fresh Red Delicious apples (RW), was determined by high performance liquid chromatography (HPLC), and total phenols were determined by the Folin-Ciocalteau method. HPLC analysis identified and quantified several classes of phenolic compounds: cinnamates, anthocyanins, flavan-3-ols and flavonols. Phloridzin and hydroxy methyl furfural were also identified. The profile of phenolic compounds varied among the juices. The range of concentrations as a percentage of total phenolic concentration was: hydroxy methyl furfural, 4-30%; phloridzin, 22-36%; cinnamates, 25-36%; anthocyanins, n.d.; flavan-3-ols, 8-27%; flavonols, 2-10%. The phenolic profile of the Red Delicious apple extracts differed from those of the juices. The range of concentrations of phenolic classes in fresh apple extracts was: hydroxy methyl furfural, n.d.; phloridzin, 11-17%; cinnamates, 3-27%; anthocyanins, n.d.-42%; flavan-3-ols, 31-54%; flavonols, 1-10%. The ability of compounds in apple juices and extracts from fresh apple to protect LDL was assessed using an in vitro copper catalyzed human LDL oxidation system. The extent of LDL oxidation was determined as hexanal production using static headspace gas chromatography. The apple juices and extracts, tested at 5 microM gallic acid equivalents (GAE), all inhibited LDL oxidation. The inhibition by the juices ranged from 9 to 34%, and inhibition by RF, RW and RP was 21, 34 and 38%, respectively. Regression analyses revealed no significant correlation between antioxidant activity and either total phenolic concentration or any specific class of phenolics. Although the specific components in the apple juices and extracts that contributed to antioxidant activity have yet to be identified, this study found that both fresh apple and commercial apple juices inhibited copper-catalyzed LDL oxidation. The in vitro antioxidant activity of apples support the inclusion of this fruit and its juice in a healthy human diet.
- Published
- 1999
- Full Text
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25. Reduced oxidative susceptibility of LDL from patients participating in an intensive atherosclerosis treatment program.
- Author
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Parks EJ, German JB, Davis PA, Frankel EN, Kappagoda CT, Rutledge JC, Hyson DA, and Schneeman BO
- Subjects
- Aged, Apolipoproteins B blood, Cholesterol blood, Copper chemistry, Coronary Artery Disease blood, Diet, Fat-Restricted, Exercise, Female, Humans, Male, Middle Aged, Particle Size, Vitamin E blood, beta Carotene blood, Coronary Artery Disease therapy, Lipid Peroxidation, Lipoproteins, LDL blood
- Abstract
The goal of this investigation was to determine whether participation in an atherosclerosis treatment program would reduce the oxidative susceptibility of LDL from patients with coronary artery disease. The treatment program included intensive exercise therapy, stress management, and consumption of a diet containing 10% fat. The size and antioxidant and lipid contents of LDL particles from 25 patients were analyzed at baseline and after 3 mo of therapy. The susceptibility of LDL to copper-mediated oxidation was measured by a conjugated diene assay and headspace gas chromatography (HSGC). Atherosclerosis treatment significantly reduced plasma total cholesterol and apolipoprotein B concentrations and the molar ratio of LDL cholesterol ester to apolipoprotein B (P < 0.01). The LDL content of alpha-tocopherol and beta-carotene was increased (27% and 17%, respectively, P < 0.04) and the molar ratio of LDL cholesterol ester the sum of LDL alpha-tocopherol and LDL beta-carotene decreased from 159 at baseline to 122 at 3 mo (P < 0.01). The lag phase of LDL conjugated diene formation increased 24%, whereas the maximum rate of oxidation slowed 29% (P < 0.01). As assessed by HSGC, copper-catalyzed formation of volatile lipid oxidation products was reduced 15% (P < 0.007); the reduction in volatiles was correlated with an increase in the alpha-tocopherol content of LDL (r=-0.48, P < 0.01). The principal determinants of reduced LDL oxidative susceptibility were the particle contents of alpha-tocopherol and beta-carotene. To our knowledge, this is the first report to document a reduction in LDL oxidation in coronary artery disease patients undergoing atherosclerosis-reversal therapy.
- Published
- 1998
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26. Hazards of powdered surgical gloves.
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Davis PA, Corless DJ, and Wastell O
- Subjects
- Animals, Equipment Contamination, Gloves, Surgical standards, Humans, Rats, Gloves, Surgical adverse effects, Powders adverse effects, Wound Infection etiology
- Published
- 1997
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27. Use of the Food Guide Pyramid and US Dietary Guidelines to improve dietary intake and reduce cardiovascular risk in active-duty Air Force members.
- Author
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Gambera PJ, Schneeman BO, and Davis PA
- Subjects
- Adult, Body Mass Index, Body Weight physiology, Cardiovascular Diseases physiopathology, Cholesterol blood, Cholesterol, HDL blood, Cholesterol, LDL blood, Exercise, Female, Humans, Male, Oxygen Consumption physiology, Physical Education and Training, Risk Factors, Triglycerides blood, United States epidemiology, Cardiovascular Diseases epidemiology, Cardiovascular Diseases prevention & control, Diet standards, Military Personnel, Nutrition Policy
- Abstract
Objective: To determine whether adoption of dietary patterns consistent with the US Dietary Guidelines for Americans and the Food Guide Pyramid, combined with exercise training, result in significant reductions in cardiovascular risk compared with a regimen of exercise therapy alone., Design: A randomized trial to compare the effects of exercise alone (n = 17) with the effects of exercise and dietary intervention (n = 15)., Setting: McClellan Air Force Base medical clinic (Sacramento, Calif)., Subjects: Thirty-two members of the Air Force (20 men and 12 women) were recruited at the time they entered a 90-day fitness improvement program. Mean age was 32 years., Intervention: All subjects participated in a 90-day fitness program. Half of the group received individualized dietary counseling using the Food Guide Pyramid as a primary educational tool., Main Outcome Measures: Changes in body mass index, plasma lipids and lipoprotein levels, aerobic capacity, and dietary intake were selected to evaluate the effectiveness of the intervention., Statistical Analyses Performed: Outcome measures were evaluated by analysis of variance. A paired t test was performed to compare changes in food-group servings and food-group fat intake from baseline values for the exercise-plus-diet group., Results: Percentage of energy from fat decreased from 39% to 23% for the exercise-plus-diet group, and servings from each of the food groups changed to reflect current guidelines. This group also had significant reductions in body mass index, total cholesterol level, and low-density lipoprotein level: 2% (P = .0001), 9% (P = .003), and 13% (P = .005), respectively. No change was observed for the exercise-only group. Additionally, a significant improvement in maximum oxygen consumption (P = .01) of 38% (vs 14% for the control group) was achieved., Conclusions: Dietary modification in accordance with the Food Guide Pyramid and the US Dietary Guidelines results in significant reductions in known cardiovascular risk factors and improves the response to exercise training.
- Published
- 1995
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28. Aldehyde-induced protein modifications in human plasma: protection by glutathione and dihydrolipoic acid.
- Author
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O'Neill CA, Halliwell B, van der Vliet A, Davis PA, Packer L, Tritschler H, Strohman WJ, Rieland T, Cross CE, and Reznick AZ
- Subjects
- Adult, Aldehydes blood, Antioxidants analysis, Ascorbic Acid blood, Ascorbic Acid metabolism, Humans, Lipid Peroxidation drug effects, Lipid Peroxidation physiology, Male, Middle Aged, Smoking adverse effects, Smoking blood, Sulfhydryl Compounds blood, Thioctic Acid pharmacology, Vitamin E blood, Aldehydes pharmacology, Glutathione pharmacology, Sulfhydryl Compounds metabolism, Thioctic Acid analogs & derivatives
- Abstract
Exposure of human plasma to gas phase cigarette smoke (CS) produces a depletion of ascorbic acid, peroxidation of lipids (Frei et al. Biochem J 1991; 277: 133-8), and protein modification (as measured by protein carbonyl accumulation and loss of sulfhydryl groups) (Reznick et al. Biochem J 1992; 286: 607-11). CS contains both saturated and unsaturated aldehydes. The contribution of these aldehydes to the damaging effects of CS on human plasma was investigated. Aldehydes present in CS did not cause a depletion of plasma antioxidants such as ascorbic acid or alpha-tocopherol and did not induce plasma lipid peroxidation. Aldehydes decreased plasma protein sulfhydryl concentrations but increased protein carbonyls. The thiols glutathione and dihydrolipoic acid had a significant effect in reducing aldehyde-induced protein modifications.
- Published
- 1994
29. Overfeeding increases very low density lipoprotein diameter and causes the appearance of a unique lipoprotein particle in association with failed yolk deposition.
- Author
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Walzem RL, Davis PA, and Hansen RJ
- Subjects
- Animals, Chemical Fractionation, Chickens blood, Female, Lipoproteins, HDL blood, Lipoproteins, HDL chemistry, Lipoproteins, VLDL chemistry, Molecular Weight, Ovarian Follicle physiology, Particle Size, Animal Feed, Chickens physiology, Egg Yolk, Lipoproteins blood, Lipoproteins, VLDL blood
- Abstract
Structurally specific very low density lipoprotein (VLDL) particles are presumed to redirect VLDL uptake during yolk deposition. Egg production is an energy intensive process, but energy excess negatively affects egg production. This study sought to determine whether overfeeding changed hen lipoprotein profiles, and if so, whether changes were related to egg production. Overfeeding caused 33% of hens to stop yolk deposition and reabsorb unovulated follicles (involute). VLDL of control hens possessed characteristic small particle size (30 nm) and composition indicative of limited intravascular metabolism. Overfeeding generally increased VLDL diameter, the effect being slight (+6.6 nm) in overfed laying hens when compared to overfed-involuted hens (+51.2 nm). Changes in composition indicated that increased intravascular metabolism of VLDL parallelled increases in particle diameter. Overfed-involuted hens showed significant elevations of plasma low density lipoprotein, VLDL cholesteryl ester, and high density lipoprotein (HDL) triacylglycerol content. Overfeeding increased plasma HDL, and in association with involution, caused redistribution of HDL particle sizes, including the appearance of novel HDL approximately 20 nm in diameter, termed HDLR, and a 97 kDa protein within the HDL fraction. The overfed hen model may provide new insight into the role of lipoprotein physical properties in determining the metabolism of triacylglycerol-rich lipoprotein, and the process of reverse lipid transport. Overfeeding generally increases VLDL size and plasma HDL levels suggesting that increased peripheral metabolism, and perhaps mechanical exclusion of enlarged VLDL by the granulosa basal lamina, contribute to the obesity and impaired yolk deposition observed in hens with excessive energy intakes. Temporal definition of massive VLDL enlargement relative to follicular collapse remains to be established.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1994
30. Bacteriophage T7 RNA polymerase and its active-site mutants. Kinetic, spectroscopic and calorimetric characterization.
- Author
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Osumi-Davis PA, Sreerama N, Volkin DB, Middaugh CR, Woody RW, and Woody AY
- Subjects
- Amino Acid Sequence, Bacteriophage T7 genetics, Base Sequence, Binding Sites, Calorimetry, Differential Scanning, Circular Dichroism, DNA-Directed RNA Polymerases genetics, Hydrogen-Ion Concentration, Kinetics, Molecular Sequence Data, Mutation, Protein Conformation, Protein Structure, Secondary, Spectrometry, Fluorescence, Spectrophotometry, Ultraviolet, Templates, Genetic, Thermodynamics, Transcription, Genetic, Bacteriophage T7 enzymology, DNA-Directed RNA Polymerases chemistry, DNA-Directed RNA Polymerases metabolism
- Abstract
It has been demonstrated that the amino acids Asp537, Asp812, Lys631, His811 and Tyr639 are involved in bacteriophage T7 RNA polymerase catalysis. In the present paper, we report kinetic, spectroscopic and calorimetric characterization of the wild-type and mutant T7 RNA polymerases generated at these five loci (D537N, E; K631M, R; Y639F, S, A, W; H811Q, A; D812N, E). The wild-type enzyme has a substantial amount of secondary structure as determined by CD analysis (alpha-helix, 43%; beta-sheet, 14%; beta-turn, 25%; unordered, 18%). The CD spectra of 12 mutants at five loci are very similar to that of the wild-type, except for the mutant Y639W. Within experimental error, the thermal transition temperatures measured by CD and DSC as well as the lambda max values of the fluorescence spectra were the same for the wild-type and all of the mutants. Therefore, the overall folding and stability of the mutant enzymes are very similar to those of the wild-type enzyme, although small local conformational changes cannot be excluded. For the synthesis of the pentamer pppGGACU, the mutants D537E and D812E showed an approximately two- to threefold decrease in (kcat)app and an approximately two- to threefold increase in (Km)app, relative to the wild-type, in contrast to the mutants D537N and D812N which exhibited no detectable activity. The mutant K631R showed a sevenfold reduction in (kcat)app and a two- to threefold increase in (Km)app, supporting our earlier observation with the mutant K631M that Lys631 may be involved in phosphodiester bond formation. The mutant Y639S can synthesize the trimer GGA with an approximately 50-fold decrease in (kcat)app and a tenfold increase in (Km)app, relative to the wild-type, underlining the importance of the phenyl ring of Tyr639. The mutant H811A, in which the side-chain at position 811 is incapable of forming a hydrogen bond, can synthesize the trimer GGA with an approximately tenfold decrease in (kcat)app and an approximately 35-fold increase in (Km)app. Thus, either the hydrogen-bonding capacity of this residue is non-essential or some other group can functionally substitute for the His811 side-chain. The wild-type enzyme showed significant effects of the base position in the sequence on the apparent binding constants for the NTPs. The kinetics of GpG-primed trimer, tetramer and pentamer synthesis on three 22 bp templates were investigated for the wild-type and mutant enzymes with measurable activity.(ABSTRACT TRUNCATED AT 400 WORDS)
- Published
- 1994
- Full Text
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31. Flexible granulocyte colony-stimulating factor dosing in ovarian cancer patients who receive dose-intense taxol therapy.
- Author
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Link CJ Jr, Bicher A, Kohn EC, Christian MC, Davis PA, Adamo DO, Reed E, and Sarosy GA
- Subjects
- Dose-Response Relationship, Drug, Female, Hematopoiesis drug effects, Humans, Neutropenia prevention & control, Granulocyte Colony-Stimulating Factor administration & dosage, Ovarian Neoplasms drug therapy, Paclitaxel administration & dosage
- Abstract
As has been reported with other chemotherapeutic agents, evidence is emerging to suggest that increased taxol dose intensity is associated with improved therapeutic efficacy. Granulocyte colony-stimulating factor (G-CSF) effectively protects the bone marrow from taxol-induced neutropenia and allows for higher taxol dose administration. This report addresses the optimal use of G-CSF as a supportive agent for dose-intense taxol therapy. Forty-seven patients were evaluated. Each ovarian cancer patient received taxol with G-CSF support, with starting doses of 250 mg/m2 per 21 days and 10 micrograms/kg/d, respectively. Five patients were treated with the same dose of G-CSF for multiple cycles. Forty-two patients were given "flexible" G-CSF dosing. Instead of reducing taxol dose after a cycle of therapy complicated by febrile neutropenia (F+N+), the G-CSF dose was increased. Only after a second episode of F+N+ was the taxol dose reduced. The initial 5 patients who developed F+N+ after taxol (250 mg/m2) and G-CSF (10 micrograms/kg/d) were retreated at the same doses of both drugs; subsequently, 4 of 5 patients had another episode of F+N+. With flexible G-CSF dosing, taxol dose intensity could be maintained at the target level in 34 of 42 patients (81% of the cohort). Sixteen of these patients (38% of the cohort) would have required taxol dose reductions for F+N+ if flexible G-CSF dosing had not been used. By increasing the G-CSF dose when indicated, patients at high risk for recurrence of F+N+, because they had already experienced one episode, appeared to have a lower risk of developing a recurrent episode. These data suggest that flexible G-CSF dosing may have merit and may allow the administration of more dose-intense taxol. A prospective, randomized, controlled clinical trial of flexible G-CSF dosing versus fixed-dose G-CSF appears warranted.
- Published
- 1994
32. Prune fiber or pectin compared with cellulose lowers plasma and liver lipids in rats with diet-induced hyperlipidemia.
- Author
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Tinker LF, Davis PA, and Schneeman BO
- Subjects
- Analysis of Variance, Animals, Apolipoproteins analysis, Cecum anatomy & histology, Cecum drug effects, Cellulose therapeutic use, Cholesterol analysis, Cholesterol blood, Diet adverse effects, Disease Models, Animal, Eating, Hyperlipidemias blood, Hyperlipidemias etiology, Intestine, Small anatomy & histology, Intestine, Small drug effects, Lipoproteins blood, Liver anatomy & histology, Liver chemistry, Male, Organ Size, Pectins therapeutic use, Random Allocation, Rats, Rats, Wistar, Triglycerides analysis, Triglycerides blood, Cellulose pharmacology, Dietary Fiber therapeutic use, Fruit, Hyperlipidemias diet therapy, Liver metabolism, Pectins pharmacology
- Abstract
Previous research indicated that prunes in the diet of men with hypercholesterolemia lowered plasma and LDL cholesterol concentrations. To further study lipid metabolism in response to ingesting prunes, we conducted an animal study to test the hypotheses that fiber extracted from prunes, compared with purified cellulose, lowers plasma and liver cholesterol in rats with diet-induced hyperlipidemia and that the response is dose dependent. Rats were randomly assigned to one of five experimental diet groups. Four of the diets contained cholesterol and cholic acid to induce hyperlipidemia. The fiber source in the hyperlipidemic diets was 6% cellulose, 3% prune fiber, 6% prune fiber or 3% pectin. The fifth group, the nonhyperlipidemic control, was fed a diet containing 6% cellulose without cholesterol or cholic acid. Rats consumed one of the five diets ad libitum for 28 d, then were killed after 16 h without food. Plasma, LDL and liver cholesterol concentrations were higher in the hyperlipidemic control than the nonhyperlipidemic control and lower in the groups fed diets containing pectin or prune fiber than in the hyperlipidemic control group. No differences in plasma or liver cholesterol concentrations were detected between groups fed either dose level of prune fiber or between groups fed 6% prune fiber and pectin. These results indicate that fiber extracted from prunes lowers plasma and liver cholesterol in hyperlipidemic rats, although a dose-dependent response was not detected.
- Published
- 1994
- Full Text
- View/download PDF
33. Asp537, Asp812 are essential and Lys631, His811 are catalytically significant in bacteriophage T7 RNA polymerase activity.
- Author
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Osumi-Davis PA, de Aguilera MC, Woody RW, and Woody AY
- Subjects
- Base Sequence, Binding Sites genetics, Binding Sites physiology, DNA-Directed RNA Polymerases chemistry, DNA-Directed RNA Polymerases genetics, Kinetics, Molecular Sequence Data, Mutagenesis, Site-Directed, Oligodeoxyribonucleotides metabolism, Transcription, Genetic genetics, Viral Proteins, Aspartic Acid metabolism, DNA-Directed RNA Polymerases metabolism, Histidine metabolism, Lysine metabolism, T-Phages enzymology
- Abstract
To define catalytically essential residues of bacteriophage T7 RNA polymerase, we have generated five mutants of the polymerase, D537N, K631M, Y639F, H811Q and D812N, by site-directed mutagenesis and purified them to homogeneity. The choice of specific amino acids for mutagenesis was based upon photoaffinity-labeling studies with 8-azido-ATP and homology comparisons with the Klenow fragment and other DNA/RNA polymerases. Secondary structural analysis by circular dichroism indicates that the protein folding is intact in these mutants. The mutants D537N and D812N are totally inactive. The mutant K631M has 1% activity, confined to short oligonucleotide synthesis. The mutant H811Q has 25% activity for synthesis of both short and long oligonucleotides. The mutant Y639F retains full enzymatic activity although individual kinetic parameters are somewhat different. Kinetic parameters, (kcat)app and (Km)app for the nucleotides, reveal that the mutation of Lys to Met has a much more drastic effect on (kcat)app than on (Km)app, indicating the involvement of K631 primarily in phosphodiester bond formation. The mutation of His to Gln has effects on both (kcat)app and (Km)app; namely, three- to fivefold reduction in (kcat)app and two- to threefold increase in (Km)app, implying that His811 may be involved in both nucleotide binding and phosphodiester bond formation. The ability of the mutant T7 RNA polymerases to bind template has not been greatly impaired. We have shown that amino acids D537 and D812 are essential, that amino acids K631 and H811 play significant roles in catalysis, and that the active site of T7 RNA polymerase is composed of different regions of the polypeptide chain. Possible roles for these catalytically significant residues in the polymerase mechanism are discussed.
- Published
- 1992
- Full Text
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34. Postprandial lipid response following a high fat meal in rats adapted to dietary fiber.
- Author
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Redard CL, Davis PA, Middleton SJ, and Schneeman BO
- Subjects
- Animals, Apolipoproteins A genetics, Apolipoproteins B genetics, Body Weight, Cellulose administration & dosage, Cholesterol blood, Edible Grain, Intestines chemistry, Liver chemistry, Liver growth & development, Male, Organ Size, Phospholipids blood, Psyllium, RNA, Messenger analysis, Rats, Rats, Inbred Strains, Stomach growth & development, Triglycerides blood, Apolipoproteins blood, Dietary Fats administration & dosage, Dietary Fiber administration & dosage, Lipoproteins blood
- Abstract
Rats were adapted to diets containing 5 g/100 g cellulose (CL), 5 g/100 g oat bran fiber (OB) or 5 g/100 g psyllium husk (Psy) for 4 wk. Following a 12-h fast, animals were either killed at 0 h (baseline) or fed 4.5 g of a test meal that provided 50% energy from fat, then killed at 1, 4 or 6 h postprandially. Fasting plasma and HDL cholesterol concentrations were lower in Psy-fed animals than in rats fed either CL or OB. Plasma triglycerides increased significantly from baseline (0 h) in all groups but did not differ among diet treatments. Increases in triglyceride content of the treatments. Increases in triglyceride content of the chylomicron/VLDL fraction occurred in the CL- and OB-fed groups and in the HDL fraction of the Psy-fed group during the postprandial period. In unfed animals the hepatic and intestinal levels of apolipoprotein A-IV mRNA were higher in the CL-fed group than in the groups fed OB and Psy. Apolipoprotein B mRNA was higher in the intestine of the OB-fed group than in the groups fed CL and Psy and had a significant gradient along the small intestine, increasing in the distal third. The results suggest that chronic consumption of fiber is less likely to modify the acute plams triglyceride response to a fat-containing test meal than if a fiber supplement is incorporated into the meal.
- Published
- 1992
- Full Text
- View/download PDF
35. The transient hypercholesterolemia of major weight loss.
- Author
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Phinney SD, Tang AB, Waggoner CR, Tezanos-Pinto RG, and Davis PA
- Subjects
- Abdomen, Adipose Tissue chemistry, Adult, Analysis of Variance, Body Composition, Cholesterol analysis, Cholesterol, HDL blood, Cholesterol, LDL blood, Energy Intake, Female, Humans, Obesity blood, Cholesterol blood, Diet, Reducing, Hypercholesterolemia etiology, Obesity diet therapy, Weight Loss physiology
- Abstract
Serum lipoproteins, body composition, and adipose cholesterol contents of six obese women were studied during and after major weight loss by very-low-calorie diets (VLCDs). Subjects started at 168 +/- 11% of ideal body weight, lost 30.3 +/- 3.7 kg in 5-7 mo, followed by 2+ mo in weight maintenance. Serum cholesterol fell from a prediet (baseline) value of 5.49 +/- 0.32 to 3.62 +/- 0.31 mmol/L (P less than 0.01) after 1-2 mo of VLCDs (nadir), after which it rose to 5.95 +/- 0.36 mmol/L (peak, P less than 0.01 compared with nadir and baseline) as weight loss continued. With weight maintenance, serum cholesterol fell to 4.92 +/- 0.34 mmol/L (P less than 0.05 compared with peak). Adipose cholesterol content did not change in peripheral (arm and leg) biopsy sites but rose significantly in abdominal adipose tissue with weight loss. We conclude that major weight loss was associated with a late rise in serum cholesterol, possibly from mobilization of adipose cholesterol stores, which resolved when weight loss ceased.
- Published
- 1991
- Full Text
- View/download PDF
36. Consumption of prunes as a source of dietary fiber in men with mild hypercholesterolemia.
- Author
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Tinker LF, Schneeman BO, Davis PA, Gallaher DD, and Waggoner CR
- Subjects
- Adult, Aged, Bile Acids and Salts analysis, Cholesterol, LDL blood, Defecation, Dietary Carbohydrates administration & dosage, Dietary Fats administration & dosage, Feces chemistry, Humans, Lipids blood, Male, Middle Aged, Pectins therapeutic use, Dietary Fiber therapeutic use, Fruit, Hypercholesterolemia diet therapy
- Abstract
Forty-one free-living adult men with mild hypercholesterolemia (5.2-7.5 mmol/L) voluntarily participated in an 8-wk crossover study designed to determine the effect of prunes as a source of fiber on plasma cholesterol and on fecal output and bile acid concentration. During the prune period, subjects supplemented their usual diets with 12 prunes (100 g; 6 g dietary fiber) daily. Plasma low-density-lipoprotein cholesterol was significantly lower after the prune period (3.9 mmol/L) than after the grape-juice-control period (4.1 mmol/L). Fecal bile acid concentration of lithocholic acid was significantly lower after the prune period (0.95 mg bile acid/g dry wt stool) than after the grape-juice-control period (1.20 mg bile acid/g dry wt stool). Both fecal wet and dry weights were approximately 20% higher after the prune period than after the grape-juice-control period. Total bile acids (mg/72 h) did not significantly differ between experimental periods.
- Published
- 1991
- Full Text
- View/download PDF
37. Dietary fiber and gender: effect on postprandial lipemia.
- Author
-
Redard CL, Davis PA, and Schneeman BO
- Subjects
- Adult, Cholesterol, VLDL blood, Dietary Fiber metabolism, Female, Food, Humans, Lipoproteins blood, Male, Sex Factors, Time Factors, Triglycerides blood, Dietary Fiber pharmacology, Lipids blood
- Abstract
The ability of guar gum and oat bran to alter postprandial lipemia and lipoprotein composition when added to a test meal (42% total calories as carbohydrate, 16% as protein, and 42% as fat) was examined in six males and six females who consumed both low- (0.4 g) and high- (15.4 g) fiber test meals on separate days. After an overnight fast participants consumed the test meal, and blood samples were obtained hourly for 8 h. Plasma glucose concentrations did not increase markedly after either meal in any of the subjects. In males, postprandial triglyceridemia was unaffected by fiber supplementation. In females, postprandial triglyceridemia was greater for the high- than for the low-fiber meal at 2, 3, and 4 h. After both meals triglyceridemia was higher in males than in females, which may be related to the lower ratio of high-density lipoprotein2 (HDL)2 to HDL3 in males vs females. Fiber supplementation and gender influence postprandial glycemia, lipemia, and lipoprotein composition.
- Published
- 1990
- Full Text
- View/download PDF
38. The enzymatic exchange of the acyl group of acyl dihydroxyacetone phosphate with free fatty acids.
- Author
-
Davis PA and Hajra AK
- Subjects
- Animals, Dithionitrobenzoic Acid pharmacology, Fatty Acids, Unsaturated metabolism, Hexokinase metabolism, Magnesium pharmacology, Mice, Microsomes drug effects, Palmitic Acids metabolism, Structure-Activity Relationship, Carcinoma, Ehrlich Tumor metabolism, Dihydroxyacetone Phosphate metabolism, Fatty Acids, Nonesterified metabolism, Microsomes metabolism, Trioses metabolism
- Published
- 1977
39. Assay and properties of the enzyme catalyzing the biosynthesis of 1-O-alkyl dihydroxyacetone 3-phosphate.
- Author
-
Davis PA and Hajra AK
- Subjects
- Animals, Carbon Radioisotopes, Fatty Acids, Nonesterified, Kinetics, Magnesium pharmacology, Mice, Phosphorus Radioisotopes, Radioisotope Dilution Technique, Substrate Specificity, Alkyl and Aryl Transferases, Carcinoma, Ehrlich Tumor enzymology, Microsomes enzymology, Transferases metabolism
- Published
- 1981
- Full Text
- View/download PDF
40. Clearance of instilled surfactant lipid from the lungs of unanesthetized sheep: lipids are differentially transported by nonlymphatic pathways.
- Author
-
Davis PA, Gunther RA, and Cross CE
- Subjects
- 1,2-Dipalmitoylphosphatidylcholine metabolism, Animals, Cholesterol metabolism, Lung blood supply, Lymphatic System physiology, Metabolic Clearance Rate, Microcirculation, Sheep, Lung metabolism, Pulmonary Surfactants metabolism
- Abstract
The routes used by the lung to dispose of instilled exogenous surfactant lipid components were examined with the sheep chronic lung lymph fistula preparation. Small vesicles of radiolabeled dipalmitoyl phosphatidylcholine (DPPC) either alone or with radiolabeled cholesterol (CHOL) were instilled intratracheally, and samples of lung lymph and plasma were collected at 60-minute intervals for 12 hours. At any time point, the total amounts of either labeled DPPC or CHOL that appeared in lung lymph were small fractions (less than 0.5%) of their respective amounts in plasma. Labeled DPPC, as DPPC alone or as DPPC/CHOL (2:1 molar ratio), appeared simultaneously in plasma and lymph and displayed the same time course of appearance regardless of vesicle composition. CHOL appearance was also simultaneous in both plasma and lymph, but was distinctly slower than that of DPPC. The time differences noted between the appearance of labeled DPPC and CHOL in lymph and plasma indicate that these two lipid components of the instilled surfactant lipid component vesicles appear to be handled in different fashions during their transport from the lung. Further, the data obtained by sampling lung lymph suggest that the lung interstitial space may not play an active role in the transport of exogenously administered lipid from the lung.
- Published
- 1987
41. Elevated levels of apolipoprotein E in the high density lipoproteins of human cord blood plasma.
- Author
-
Blum CB, Davis PA, and Forte TM
- Subjects
- Adult, Cholesterol blood, Cholesterol, HDL blood, Cholesterol, LDL blood, Female, Humans, Pregnancy, Triglycerides blood, Apolipoproteins E blood, Fetal Blood analysis, Lipoproteins, HDL blood
- Abstract
The concentrations and lipoprotein distributions of apolipoprotein E (apoE) in normal human umbilical cord blood plasma were determined. The mean plasma apoE level of 95 neonates was considerably higher than that of 49 normal adults (58.1 vs 35.8 micrograms/ml). This elevation of apoE levels was in striking contrast to the lower than adult levels of cholesterol (72 mg/dl vs 185 mg/dl), triglyceride (37.8 mg/dl vs 97.6 mg/dl), and LDL cholesterol (25 mg/dl vs 110 mg/dl) in neonatal plasma. For the group of 95 neonates, the plasma apoE concentration correlated significantly with total plasma cholesterol concentration (r = 0.60), with LDL cholesterol concentration (r = 0.27) and with HDL cholesterol concentration (r = 0.50). Among the neonates, 87% of plasma apoE was associated with a less dense subfraction of high density lipoprotein compared to a mean of 58% for 30 normal adults. Thus, for neonates, despite hypolipidemia, the absolute concentration of apoE in HDL (50 micrograms/ml) was 2.5 times that of adults (20 micrograms/ml). We speculate that the very low level of neonatal VLDL, providing limited substrate for lipolysis, may result in retarded removal of apoE from plasma and the observed high level of apoE in neonatal HDL. We hypothesize that in the fetus and neonate, as has been demonstrated in abetalipoproteinemia, apoE-rich HDL may functionally substitute for LDL in delivering cholesterol to cells.
- Published
- 1985
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