32 results on '"Dey, D."'
Search Results
2. Rapidly progressive coronary atherosclerosis in a young male: a retrospective advanced CCT phenotype analysis.
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Lorenzatti D, Filtz A, Latib A, DeRose J, Dey D, Berman DS, Garcia MJ, and Slipczuk L
- Abstract
We present a real-life case of a very young man with multiple risk factors who progressed rapidly from minimally obstructive non-calcified plaque on computed tomography angiography (CCTA) to severe three-vessel coronary disease presenting with STEMI. It questions the reliability of zero coronary calcium in high-risk subgroups like familial hypercholesterolemia, high Lp(a), and the young. While CCTA can accurately visualize non-calcified plaque, its interpretation requires expertise and clinical judgment should consider both imaging and clinical risk factors for management. Advanced plaque quantification, peri-coronary (PCAT), and epicardial (EAT) adipose tissue could help better-stratified patients but the evidence-based clinical application remains unknown., (© 2024. The Author(s).)
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- 2024
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3. Noninvasive Atherosclerotic Phenotyping: The Next Frontier into Understanding the Pathobiology of Coronary Artery Disease.
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Wolny R, Geers J, Grodecki K, Kwiecinski J, Williams MC, Slomka PJ, Hasific S, Lin AK, and Dey D
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- Humans, Tomography, X-Ray Computed, Computed Tomography Angiography methods, Coronary Vessels diagnostic imaging, Coronary Vessels pathology, Risk Assessment methods, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease pathology, Coronary Artery Disease diagnosis, Plaque, Atherosclerotic diagnostic imaging, Plaque, Atherosclerotic pathology, Phenotype
- Abstract
Purpose of Review: Despite recent advances, coronary artery disease remains one of the leading causes of mortality worldwide. Noninvasive imaging allows atherosclerotic phenotyping by measurement of plaque burden, morphology, activity and inflammation, which has the potential to refine patient risk stratification and guide personalized therapy. This review describes the current and emerging roles of advanced noninvasive cardiovascular imaging methods for the assessment of coronary artery disease., Recent Findings: Cardiac computed tomography enables comprehensive, noninvasive imaging of the coronary vasculature, and is used to assess luminal stenoses, coronary calcifications, and distinct adverse plaque characteristics, helping to identify patients prone to future events. Novel software tools, implementing artificial intelligence solutions, can automatically quantify and characterize atherosclerotic plaque from standard computed tomography datasets. These quantitative imaging biomarkers have been shown to improve patient risk stratification beyond clinical risk scores and current clinical interpretation of cardiac computed tomography. In addition, noninvasive molecular imaging in higher risk patients can be used to assess plaque activity and plaque thrombosis. Noninvasive imaging allows unique insight into the burden, morphology and activity of atherosclerotic coronary plaques. Such phenotyping of atherosclerosis can potentially improve individual patient risk prediction, and in the near future has the potential for clinical implementation., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2024
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4. Secondary metabolite fingerprinting, anti-pathogenic activity, elite chemotype selection and conservation of Curcuma caesia - an ethnomedicinally underutilized species.
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Chakraborty A, Mukherjee S, Santra I, Dey D, Mukherjee S, and Ghosh B
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Curcuma caesia Roxb. is an ethnomedicinally important, essential oil (EO) yielding aromatic plant. A total of twelve accessions of this plant rhizome were collected from six different agro-climatic zones of West Bengal, India and evaluated for their antimicrobial activities against eight disease-causing, multi-drug-resistant pathogenic strains of urinary-tract infection and respiratory-tract infection. The EO and extracts demonstrated antibacterial activity, with the highest inhibition zone of 18.00 ± 0.08 and 17.50 ± 0.14 mm against Klebsiella pneumoniae by accession 06, even where all the broad-spectrum antibiotics failed to respond. In this study, we employed high-performance thin-layer chromatography (HPTLC) to quantify curcumin, the primary secondary metabolite of C. caesia , and the highest 0.228 mg/gm of curcumin resulted from accession 06. Hence, on the basis of all aspects, accession 06 was identified as the elite chemotype among all twelve accessions. The chemical profiling of EO from accession 06 was done using gas chromatography-mass spectroscopy (GC-MS). Conceivably, about 13 medicinally significant compounds were detected. As this plant species is seasonal and has difficulties in conventional breeding due to dormancy, it must be conserved through in vitro tissue culture for a steady supply throughout the year in massive amounts for agricultural demand. A maximum number of 19.28 ± 0.37 shoots has been obtained in MS medium fortified with 6-Benzylaminopurine, Kinetin, and Naphthalene acetic acid. The genetic uniformity of the plants has been studied through Start Codon Targeted Polymorphism. Therefore, this study must help meet the need for essential phytoactive compounds through a simple, validated, and reproducible plant tissue culture protocol throughout the year., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© King Abdulaziz City for Science and Technology 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
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- 2024
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5. Does Coronary Plaque Morphology Matter Beyond Plaque Burden?
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Lorenzatti D, Piña P, Csecs I, Schenone AL, Gongora CA, Garcia MJ, Blaha MJ, Budoff MJ, Williams MC, Dey D, Berman DS, Virani SS, and Slipczuk L
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- Humans, Coronary Angiography methods, Tomography, X-Ray Computed methods, Computed Tomography Angiography methods, Predictive Value of Tests, Coronary Vessels diagnostic imaging, Coronary Artery Disease diagnostic imaging, Plaque, Atherosclerotic diagnostic imaging, Myocardial Infarction
- Abstract
Purpose of Review: Imaging of adverse coronary plaque features by coronary computed tomography angiography (CCTA) has advanced greatly and at a fast pace. We aim to describe the evolution, present and future in plaque analysis, and its value in comparison to plaque burden., Recent Findings: Recently, it has been demonstrated that in addition to plaque burden, quantitative and qualitative assessment of coronary plaque by CCTA can improve the prediction of future major adverse cardiovascular events in diverse coronary artery disease scenarios. The detection of high-risk non-obstructive coronary plaque can lead to higher use of preventive medical therapies such as statins and aspirin, help identify culprit plaque, and differentiate between myocardial infarction types. Even more, over traditional plaque burden, plaque analysis including pericoronary inflammation can potentially be useful tools for tracking disease progression and response to medical therapy. The identification of the higher risk phenotypes with plaque burden, plaque characteristics, or ideally both can allow the allocation of targeted therapies and potentially monitor response. Further observational data are now required to investigate these key issues in diverse populations, followed by rigorous randomized controlled trials., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2023
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6. Moderation of nitrogen availability through the application of pyrolyzed and unpyrolyzed organic materials in saline water irrigated soil.
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Mavi MS, Singh G, Choudhary OP, and Dey D
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- Animals, Environmental Monitoring, Charcoal chemistry, Saline Waters, Manure, Soil chemistry, Nitrogen analysis
- Abstract
Soil application of pyrolyzed biomass (biochar) has been proposed as an effective strategy for managing degraded land, but its limitations as a sole nutrient supplier discourage its widespread application as a soil amendment. Excessive use of saline water for irrigation leads to buildup of salts and other toxic ions, which cause a decline in the availability of essential nutrients due to negative effects on the mineralization process. Therefore, a long-term incubation experiment was conducted for 52 weeks to study the individual or combined impact of pyrolyzed [biochar derived from rice residue (RB)] and unpyrolyzed organic materials [rice residue (RR) and animal manure (AM)] on nitrogen (N) dynamics in soil irrigated with water of varying electrical conductivity (EC) (EC
0.3 [non-saline canal water), EC10 , and EC15 dS m-1 (saline)]. Increasing salinity had an adverse effect on N mineralization, reducing it by 20-70% during the incubation period. Irrespective of the EC, soil amended with AM showed greater and faster N mineralization than unamended control, while individual application of RB or RR showed immobilization of N during the early period of incubation. However, conjoint application of pyrolyzed (RB) and unpyrolyzed organic materials (RR or AM) showed enhanced mineralized N content (26-96%) compared with the sole biochar-amended soil irrigated with water of different EC levels. It was most likely due to the synergic effect of unpyrolyzed materials on the mineralization rate of biochar. On the other hand, the high cation exchange capacity, large surface area, and greater total porosity of the biochar may cause stronger adsorption of free NH4 + -N released from the labile organic amendments, thereby moderating the N mineralization process under saline conditions. Therefore, it is recommended that biochar be used in conjunction with AM or RR to ensure the prolonged availability of N in a saline environment., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)- Published
- 2023
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7. Role of Neutrophil to Lymphocyte Ratio in Predicting Severity of Obstructive Sleep Apnea.
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Shetty S, Chandrashekhar S, Chaya SK, Surendran A, and Dey D
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Obstructive sleep apnea (OSA) has been linked to and is associated with increased cardiovascular and cerebrovascular morbidity. Ongoing inflammatory responses play an important role in this association. Systemic inflammation is important in pathophysiology of OSA and its comorbidity. In this study, we aimed to evaluate the role of neutrophil-to-lymphocyte ratio (NLR) in OSA patients and comparing with other well-known inflammatory marker, C-reactive protein (CRP) along with thyroid-stimulating hormone(TSH) and body-mass index(BMI). We conducted a retrospective analysis of 162 patients with OSA and divided them into 2 categories based on apnea-hypopnea index (AHI) (< 30 and > = 30), and recorded their leukocyte profiles, sex, age and body mass index. 80 matched healthy controls were taken. Patients were excluded if they had underlying cancer, chronic inflammatory disease, any systemic infection, uncontrolled hypertension and diabetes mellitus, a known acute coronary syndrome, valvular heart disease, renal or hepatic dysfunction. We found that N/L Ratio in severe OSA patients was significantly higher compared with mild and moderate OSA patients and healthy controls ( p < 0.001). CRP levels were not different in all OSA stages ( p = 0.595). We noted a significant difference in mean BMI of the two groups. In the wake of increase in prevalence of OSA in a developing country like India coupled with inadequate proportion of sleep labs, NLR is an inexpensive, easy to obtain, widely available marker of inflammation that might in combination with other markers assist in identifying patients with severe OSA., Competing Interests: Conflict of InterestThe authors declare that they have no conflict of interest., (© Association of Otolaryngologists of India 2021.)
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- 2022
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8. Silver nanoparticle synthesis and their potency against multidrug-resistant bacteria: a green approach from tissue-cultured Coleus forskohlii .
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Chakraborty A, Haque SM, Ghosh D, Dey D, Mukherjee S, Maity DK, and Ghosh B
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Drug resistance is a major concern nowadays, and finding alternatives of the well-known antibiotic is necessary. Green nanoparticles are emerging as a tenable alternative to this with a large spectrum of activity. The present manuscript describes an eco-friendly approach for green synthesis of silver nanoparticles from both in vitro and in vivo leaf extract of Coleus forskohlii . Leaf extracts were used in synthesis of nanoparticles which were further analyzed through UV-Vis, dynamic light scattering, energy-dispersive spectroscopy, and transmission electron microscopy. Antimicrobial activity of silver nanoparticles alone, as well as crude extract of the plant itself, was carried out against eight multidrug-resistant respiratory tract infecting pathogenic strains. Satisfactory antimicrobial activities were found with nanoparticles, in vitro and in vivo leaf extracts. However, gradually higher to lower inhibition potential against pathogenic bacterial strains was found in silver nanoparticles, in vitro and in vivo leaf extracts. Seven bioactive compounds were detected in the crude extract through gas chromatography-mass spectroscopy analysis. Results revealed that nanoparticle formation occurred in a wide range of sizes (10-50 nm) and shapes (trigonal, hexagonal, spherical, rod). The diversity in size and shape of the nanoparticles makes them biologically active. Silver nanoparticle exhibits significantly better antimicrobial activities as compared to the plant extract in case of nearly all pathogens with a maximum zone of inhibition of 15.33 ± 0.94 mm where more than 12 well-known antibiotics failed to respond. Because of this broad-spectrum activity of nanoparticles as well as the leaf extracts against life-threatening microbes, it can be used as future generation drugs., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© King Abdulaziz City for Science and Technology 2022, Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
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- 2022
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9. Incidence of new-onset atrial fibrillation in COVID-19 is associated with increased epicardial adipose tissue.
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Slipczuk L, Castagna F, Schonberger A, Novogrodsky E, Dey D, Jorde UP, Levsky JM, Di Biase L, and Garcia MJ
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- Adipose Tissue diagnostic imaging, Aged, COVID-19 Testing, Female, Humans, Incidence, Male, Middle Aged, Pericardium diagnostic imaging, Retrospective Studies, Risk Factors, Atrial Fibrillation diagnostic imaging, Atrial Fibrillation epidemiology, COVID-19
- Abstract
Purpose: Coronary artery calcium (CAC) and epicardial adipose tissue (EAT) can predict AF in the general population. We aimed to determine if CAC and EAT measured by computed tomographic (CT) scanning can predict new-onset AF in patients admitted with COVID-19 disease., Methods: We performed a retrospective, post hoc analysis of all patients admitted to Montefiore Medical Center with a confirmed COVID-19 diagnosis from March 1st to June 23rd, 2020, who had a non-contrast CT of the chest within 5 years prior to admission. We determined ordinal CAC scores and quantified the EAT volume and examined their relationship with inpatient mortality., Results: A total of 379 patients were analyzed. There were 16 events of new-onset AF (4.22%). Patients who developed AF during the index admission were more likely to be male (75 vs 47%, p < 0.001) and had higher EAT (129.5 [76.3-197.3] vs 91.0 [60.0-129.0] ml, p = 0.049). There were no differences on age (68 [56-71] vs 68 [58-76] years; p = 0.712), BMI (28.5 [25.3-30.8] vs 26.9 [23.1-31.8] kg/m
2 ; p = 0.283), ordinal CAC score (3 [1-6] vs 2 [0-4]; p = 0.482), or prevalence of diabetes (56.3 vs 60.1%; p = 0.761), hypertension (75.0 vs 87.3%, p = 0.153), or coronary artery disease (50.0 vs 39.4%, p = 0.396). Patients with new-onset AF had worse clinical outcomes (death/intubation/vasopressors) (87.5 vs 44.1%; p = 0.001)., Conclusion: Increased EAT measured by non-contrast chest CT identifies patients hospitalized with COVID-19 at higher risk of developing new-onset AF. Patients with new-onset AF have worse clinical outcomes., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)- Published
- 2022
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10. Epicardial fat volume is associated with preexisting atrioventricular conduction abnormalities and increased pacemaker implantation rate in patients undergoing transcatheter aortic valve implantation.
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Weferling M, Rolf A, Fischer-Rasokat U, Liebetrau C, Renker M, Choi YH, Hamm CW, Dey D, and Kim WK
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Epicardial fat tissue (EFT) is a highly metabolically active fat depot surrounding the heart and coronary arteries that is related to early atherosclerosis and adverse cardiac events. We aimed to investigate the relationship between the amount of EFT and preexisting cardiac conduction abnormalities (CCAs) and the need for new postinterventional pacemaker in patients with severe aortic stenosis planned for transcatheter aortic valve implantation (TAVI). A total of 560 consecutive patients (54% female) scheduled for TAVI were included in this retrospective study. EFT volume was measured via a fully automated artificial intelligence software (QFAT) using computed tomography (CT) performed before TAVI. Baseline CCAs [first-degree atrioventricular (AV) block, right bundle branch block (RBBB), and left bundle branch block (LBBB)] were diagnosed according to 12-lead ECG before TAVI. Aortic valve calcification was determined by the Agatston score assessed in the pre-TAVI CT. The median EFT volume was 129.5 ml [IQR 94-170]. Baseline first-degree AV block was present in 17%, RBBB in 10.4%, and LBBB in 10.2% of the overall cohort. In adjusted logistic regression analysis, higher EFT volume was associated with first-degree AV block (OR 1.006 [95% CI 1.002-1.010]; p = 0.006) and the need for new pacemaker implantation after TAVI (OR 1.005 [95% CI 1.0-1.01]; p = 0.035) but not with the presence of RBBB or LBBB. EFT volume did not correlate with the Agatston score of the aortic valve. Greater EFT volume is associated independently with preexisting first-degree AV block and new pacemaker implantation in patients undergoing TAVI. It may play a causative role in degenerative processes and the susceptibility of the AV conduction system., (© 2021. The Author(s).)
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- 2022
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11. Academic Crisis During COVID 19: Online Classes, a Panacea for Imminent Doctors.
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Shetty S, Shilpa C, Dey D, and Kavya S
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Introduction: COVID 19 made a serious impact on many aspects of everyday life. The world saw a paradigm shift in the education system favouring online learning during the constrains of pandemic., Methodology: To assess the attitude of the students towards online learning in subject of ENT, we conducted an observational study among 170 third year MBBS undergraduate students of our institute attending online classes through the student portal of our university website., Results: Our survey revealed students favoured online learning to sustain their academic interest and development during this pandemic. Yet, they perceived many challenges during online learning like lack of face-to-face interactions, lack of socialization, distraction by social media, technology related issues etc. Students also opted for a combined approach of learning in the post pandemic period., Conclusion: This article reflects the challenges faced during online learning and added the innovative methods that can be included to overcome the obstacles of online learning. During this period of COVID, one must embrace the alternative to classroom learning to keep up with one's academic development and can consider an integrated approach of learning after the pandemic., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© Association of Otolaryngologists of India 2020.)
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- 2022
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12. Consensus evidence-based clinical practice guidelines for the diagnosis and treat-to-target management of osteoporosis in Africa: an initiative by the African Society of Bone Health and Metabolic Bone Diseases.
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El Miedany Y, Paruk F, Kalla A, Adebajo A, El Gaafary M, El Maghraoui A, Ngandeu M, Dey D, Gadallah N, Elwy M, Moosajee F, Abu-Zaid MH, Galal S, Miladi S, Hassan W, Fadlelmola A, and Saber S
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- Bone Density, Consensus, Delphi Technique, Humans, Fractures, Bone prevention & control, Osteoporosis diagnosis, Osteoporosis drug therapy
- Abstract
The objective of this consensus statement is to inform the clinical practice communities, research centres and policymakers across Africa of the results of the recommendations for osteoporosis prevention, diagnosis and management. The developed guideline provides state-of-the-art information and presents the conclusions and recommendations of the consensus panel regarding these issues., Purpose: To reach an African expert consensus on a treat-to-target strategy, based on current evidence for best practice, for the management of osteoporosis and prevention of fractures., Method: A 3-round Delphi process was conducted with 17 osteoporosis experts from different African countries. All rounds were conducted online. In round 1, experts reviewed a list of 21 key clinical questions. In rounds 2 and 3, they rated the statements stratified under each domain for its fit (on a scale of 1-9). After each round, statements were retired, modified or added in view of the experts' suggestions and the percent agreement was calculated. Statements receiving rates of 7-9 by more than 75% of experts' votes were considered as achieving consensus., Results: The developed guidelines adopted a fracture risk-centric approach. Results of round 1 revealed that of the 21 proposed domains, 10 were accepted whereas 11 were amended. In round 2, 32 statements were presented: 2 statements were retired for similarity, 9 statements reached consensus, whereas modifications were suggested for 21 statements. After the 3rd round of rating, the experts came to consensus on the 32 statements. Frequency of high-rate recommendation ranged from 83.33 to 100%. The response rate of the experts was 100%. An algorithm for the osteoporosis management osteoporosis was suggested., Conclusion: This study is an important step in setting up a standardised osteoporosis service across the continent. Building a single model that can be applied in standard practice across Africa will enable the clinicians to face the key challenges of managing osteoporosis; furthermore, it highlights the unmet needs for the policymakers responsible for providing bone health care together with and positive outcomes of patients' care., (© 2021. International Osteoporosis Foundation and National Osteoporosis Foundation.)
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- 2021
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13. Candidate antiviral drugs for COVID-19 and their environmental implications: a comprehensive analysis.
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Biswas P, Hasan MM, Dey D, Dos Santos Costa AC, Polash SA, Bibi S, Ferdous N, Kaium MA, Rahman MDH, Jeet FK, Papadakos S, Islam K, and Uddin MS
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- Humans, Pandemics, SARS-CoV-2, Antiviral Agents pharmacology, COVID-19 Drug Treatment
- Abstract
Emerging from Wuhan, China, SARS-CoV-2 is the new global threat that killed millions of people, and many are still suffering. This pandemic has not only affected people but also caused economic crisis throughout the world. Researchers have shown good progress in revealing the molecular insights of SARS-CoV-2 pathogenesis and developing vaccines, but effective treatment against SARS-CoV-2-infected patients are yet to be found. Several vaccines are available and used in many countries, while many others are still in clinical or preclinical studies. However, this involves a long-term process, considering the safety procedures and requirements and their long-term protection capacity and in different age groups are still questionable. Therefore, at present, the drug repurposing of the existing therapeutics previously designed against other viral diseases seems to be the only practical approach to mitigate the current situation. The safety of most of these therapeutic agents has already been tested. Recent clinical reports revealed promising therapeutic efficiency of several drugs such as remdesivir, tenofovir disoproxil fumarate, azithromycin, lopinavir/ritonavir, chloroquine, baricitinib, and cepharanthine. Besides, plasma therapies were used to treat patients and prevent fatal outcomes. Thus, in this article, we have summarized the epidemiological and clinical data from several clinical trials conducted since the beginning of the pandemic, emphasizing the efficiency of the known agents against SARS-CoV-2 and their harmful side effects on the human body as well as their environmental implications. This review shows a clear overview of the current pharmaceutical perspective on COVID-19 treatment., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2021
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14. Coronary artery calcification and epicardial adipose tissue as independent predictors of mortality in COVID-19.
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Slipczuk L, Castagna F, Schonberger A, Novogrodsky E, Sekerak R, Dey D, Jorde UP, Levsky JM, and Garcia MJ
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- Adipose Tissue diagnostic imaging, COVID-19 Testing, Coronary Vessels diagnostic imaging, Humans, Pericardium diagnostic imaging, Predictive Value of Tests, Retrospective Studies, Risk Factors, SARS-CoV-2, COVID-19, Coronary Artery Disease diagnostic imaging, Vascular Calcification diagnostic imaging
- Abstract
Recent epidemiological studies have demonstrated that common cardiovascular risk factors are strongly associated with adverse outcomes in COVID-19. Coronary artery calcium (CAC) and epicardial fat (EAT) have shown to outperform traditional risk factors in predicting cardiovascular events in the general population. We aim to determine if CAC and EAT determined by Computed Tomographic (CT) scanning can predict all-cause mortality in patients admitted with COVID-19 disease. We performed a retrospective, post-hoc analysis of all patients admitted to Montefiore Medical Center with a confirmed COVID-19 diagnosis from March 1st, 2020 to May 2nd, 2020 who had a non-contrast CT of the chest within 5 years prior to admission. We determined ordinal CAC scores and quantified the epicardial (EAT) and thoracic (TAT) fat volume and examined their relationship with inpatient mortality. A total of 493 patients were analyzed. There were 197 deaths (39.95%). Patients who died during the index admission had higher age (72, [64-80] vs 68, [57-76]; p < 0.001), CAC score (3, [0-6] vs 1, [0-4]; p < 0.001) and EAT (107, [70-152] vs 94, [64-129]; p = 0.023). On a competing risk analysis regression model, CAC ≥ 4 and EAT ≥ median (98 ml) were independent predictors of mortality with increased mortality of 63% (p = 0.003) and 43% (p = 0.032), respectively. As a composite, the group with a combination of CAC ≥ 4 and EAT ≥ 98 ml had the highest mortality. CAC and EAT measured from chest CT are strong independent predictors of inpatient mortality from COVID-19 in this high-risk cohort., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)
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- 2021
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15. African League Against Rheumatism (AFLAR) preliminary recommendations on the management of rheumatic diseases during the COVID-19 pandemic.
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Akintayo RO, Bahiri R, El Miedany Y, Olaosebikan H, Kalla AA, Adebajo AO, Migowa AN, Slimani S, Koussougbo OD, Kawther BA, Akpabio AA, Ghozlani I, Dey D, Hassan WA, Govind N, Makan K, Mohamed A, Genga EK, Ghassem MKA, Mortada M, Hamdi W, Wabi MO, Tikly M, Ngandeu-Singwe M, and Scott C
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- Female, Humans, Pandemics, SARS-CoV-2, COVID-19, Rheumatic Diseases drug therapy, Rheumatic Diseases epidemiology, Rheumatology
- Abstract
Objectives: To develop recommendations for the management of rheumatic and musculoskeletal diseases (RMDs) during the COVID-19 pandemic., Method: A task force comprising of 25 rheumatologists from the 5 regions of the continent was formed and operated through a hub-and-spoke model with a central working committee (CWC) and 4 subgroups. The subgroups championed separate scopes of the clinical questions and formulated preliminary statements of recommendations which were processed centrally in the CWC. The CWC and each subgroup met by several virtual meetings, and two rounds of voting were conducted on the drafted statements of recommendations. Votes were online-delivered and recommendations were pruned down according to predefined criteria. Each statement was rated between 1 and 9 with 1-3, 4-6 and 7-9 representing disagreement, uncertainty and agreement, respectively. The levels of agreement on the statements were stratified as low, moderate or high according to the spread of votes. A statement was retired if it had a mean vote below 7 or a 'low' level of agreement., Results: A total of 126 initial statements of recommendations were drafted, and these were reduced to 22 after the two rounds of voting., Conclusions: The preliminary statements of recommendations will serve to guide the clinical practice of rheumatology across Africa amidst the changing practices and uncertainties in the current era of COVID-19. It is recognized that further updates to the recommendations will be needed as more evidence emerges. Key Points • AFLAR has developed preliminary recommendations for the management of RMDs in the face of the COVID-19 pandemic. • COVID-19 is an unprecedented experience which has brought new concerns regarding the use of some disease-modifying anti-rheumatic drugs (DMARDs), and these recommendations seek to provide guidelines to the African rheumatologists. • Hydroxychloroquine shortage has become rampart across Africa as the drug is being used as prophylaxis against COVID-19 and this may necessitate a review of treatment plan for some patients with RMDs. • Breastfeeding should continue for as long as possible if a woman is positive for SARS-CoV-2 as there is currently no evidence that the infection can be transmitted through breast milk., (© 2020. The Author(s).)
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- 2021
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16. Capacity building for the provision of rheumatological services in sub-Saharan Africa.
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Eastin J, Dey D, Amissah-Arthur MB, Chaudhuri K, and Jawad A
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- Africa South of the Sahara, Curriculum, Humans, Rheumatologists, Capacity Building, Rheumatic Diseases therapy
- Abstract
Introduction: A project aimed to develop and deliver a clinical training course in Accra, Ghana, to increase patient access to physicians trained in the diagnosis, treatment and management of rheumatological conditions., Methods: We started with a scoping exercise followed by collaborative course curriculum development, co-delivered training course facilitated by both locally based rheumatologists and international faculty members. Evaluation data gathered from application forms, participant feedback forms and multiple-choice tests completed at the beginning and end of training and the test scores compared to evaluate a change in knowledge., Results: A 4-day clinical training course developed and delivered to twenty medical professionals based across Ghana. Test scores suggest a 15.83% increase in clinical knowledge., Conclusions: The training model with the curriculum design and delivery teams drawing expertise from both locally based rheumatologists and internationally based faculty has guaranteed both world-class approach and content while ensuring contextual relevance. The inclusion of leadership and Training of Trainer (ToT) elements into the model of training has maximised reach and increased teaching capacity. The programme has been well-received by participating medical professionals and faculty and has been demonstrated to be effective within this multinational programme and the methodology may be applicable to similar needs in other countries. Key Points • The growing burden of musculoskeletal disease in West Africa means that strengthening capacity in the specialty of rheumatology is more important than ever. • A pilot workshop to strengthen capacity in rheumatology care in Ghana with the curriculum design and delivery teams drawing expertise from both the UK and West Africa has guaranteed both world-class approach and content while ensuring contextual relevance. • The programme has been well-received by participating medical professionals and faculty and may be applicable to similar needs in other countries across sub-Saharan Africa., (© 2020. International League of Associations for Rheumatology (ILAR).)
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- 2021
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17. Application of CRISPR/Cas System in the Metabolic Engineering of Small Molecules.
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Singh R, Chandel S, Ghosh A, Dey D, Chakravarti R, Roy S, Ravichandiran V, and Ghosh D
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- Bacteria genetics, Genome, Microbial genetics, Yeasts genetics, CRISPR-Cas Systems genetics, Gene Editing methods, Metabolic Engineering methods, Small Molecule Libraries metabolism
- Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and their associated Cas protein technology area is rapidly growing technique for genome editing and modulation of transcription of several microbes. Successful engineering in microbes requires an emphasis on the aspect of efficiency and targeted aiming, which can be employed using CRISPR/Cas system. Hence, this type of system is used to modify the genome of several microbes such as yeast and bacteria. In recent years, CRISPR/Cas systems have been chosen for metabolic engineering in microbes due to their specificity, orthogonality, and efficacy. Therefore, we need to review the scheme which was acquired for the execution of the CRISPR/Cas system for the modification and metabolic engineering in yeast and bacteria. In this review, we highlighted the application of the CRISPR/Cas system which has been used for the production of small molecules in the microbial system that is chemically and biologically important.
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- 2021
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18. Biochar and urea co-application regulates nitrogen availability in soil.
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Dey D and Mavi MS
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- Animals, Charcoal, Environmental Monitoring, Fertilizers analysis, Urea, Nitrogen, Soil
- Abstract
Overuse of nitrogenous fertilizers especially urea has been considered a significant source of reactive N causing acute environmental impacts through leaching, volatilization, and N
2 O gas emission from fertilized crop fields. However, some recent studies have proposed that such environmental losses of N can be ignored by adapting an alternative way of combining nitrogenous fertilizer with pyrolyzed biomass (biochar). Therefore, the effect of co-application of rice-residue biochar (RB) or poultry manure biochar (PB) along with urea on N dynamics was investigated by conducting a 60-day incubation experiment. The results showed that urea led to greater N mineralization (0.2 µg N g-1 soil day-1 ) due to the easy availability of ammonical-N (NH4 + -N) produced from hydrolysis that acted as a substrate for nitrification. Sole application of biochars (RB or PB) or their co-application with urea resulted in 38-45% and 19-28% lower N mineralization than the sole urea amended soil, respectively. The lower N mineralization in sole biochar or biochar plus urea amended soil was most likely caused due to (1) increased C:N ratio of the biochar amended soil, (2) adsorption of NH4 + -N by biochar, (3) microbial immobilization of the nitrogen in the amended soil, and (4) lower urease activity in the treatments amended with biochar. Thus, it may be concluded that the co-application of biochar with urea can reduce N losses through moderation of N mineralization and make it available to plants for longer periods.- Published
- 2021
- Full Text
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19. Potential combination therapy using twenty phytochemicals from twenty plants to prevent SARS- CoV-2 infection: An in silico Approach.
- Author
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Dey D, Dey N, Ghosh S, Chandrasekaran N, Mukherjee A, and Thomas J
- Abstract
Covid 19 caused by novel strain SARS- CoV-2 has become a pandemic due to its contagious nature of infection. It enters by binding with ACE2 receptor present on the outer surface of a cell by cleaving S1/S2 with proteolytic protein Furin. Further viral replication or transcription then takes place with the help of main protease 3CLpro and polymerase RdRp. This in silco study was carried out to block ACE2, Furin, 3CLpro and RdRP with various phytochemicals to prevent SARS- CoV-2 entry and replication or transcription. Twenty different phytochemicals were screened to understand the drug-likeliness obeying Lipinski's rule 5 and further, molecular docking was performed using these phytochemicals to block their respective target proteins. All the phytochemicals follow Lipinski's rule of five and molecular docking result shows best binding affinity of Podofilox - 7.54 kcal/mol with ACE2, Psoralidin - 8.04 kcal/mol with Furin, Ursolic acid - 8.88 kcal/mol with 3CLpro and Epiafzelechin - 8.26 kcal/mol with RdRp. Thus, blocking two human receptors ACE2 and Furin with Podofilox and Psoralidin respectively may prevent the viral entry into the cells. Also blocking viral proteins 3CLpro and RdRp with Ursolic acid and Epiafzelechin may prevent viral replication or transcription. Using this combination therapy of blocking the receptors responsible for viral entry and viral proteins responsible for replication or transcription may prevent SARS- CoV-2 infection., Competing Interests: Conflict of interestThe authors declare no conflict of interest., (© Indian Virological Society 2021.)
- Published
- 2021
- Full Text
- View/download PDF
20. Electrically Doped Nanoscale Devices Using First-Principle Approach: A Comprehensive Survey.
- Author
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Dey D, De D, Ahmadian A, Ghaemi F, and Senu N
- Abstract
Doping is the key feature in semiconductor device fabrication. Many strategies have been discovered for controlling doping in the area of semiconductor physics during the past few decades. Electrical doping is a promising strategy that is used for effective tuning of the charge populations, electronic properties, and transmission properties. This doping process reduces the risk of high temperature, contamination of foreign particles. Significant experimental and theoretical efforts are demonstrated to study the characteristics of electrical doping during the past few decades. In this article, we first briefly review the historical roadmap of electrical doping. Secondly, we will discuss electrical doping at the molecular level. Thus, we will review some experimental works at the molecular level along with we review a variety of research works that are performed based on electrical doping. Then we figure out importance of electrical doping and its importance. Furthermore, we describe the methods of electrical doping. Finally, we conclude with a brief comparative study between electrical and conventional doping methods.
- Published
- 2021
- Full Text
- View/download PDF
21. Implementation of biomolecular logic gate using DNA and electrically doped GaAs nano-pore: a first principle paradigm.
- Author
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Dey D, Roy P, and De D
- Subjects
- Algorithms, Computer Simulation, Electric Conductivity, Electrons, Models, Molecular, Nanopores, Arsenicals chemistry, DNA chemistry, Electricity, Gallium chemistry, Logic
- Abstract
One of the emerging areas of today's research arena is molecular modeling and molecular computing. The molecular logic gate can be theoretically implemented from single-strand DNA which consists of four basic nucleobases. In this study, the electronic transmission characteristics of DNA chain are investigated to form the logic gate. This biomolecular single-strand DNA chain is passed through an electrically doped gallium-arsenide nano-pore to achieve reasonably improved transmission along <1 1 1> direction. Current-voltage characteristic and device density of states with HOMO-LUMO plot of the device are explained along with the conductivity of the device to confirm the characteristics of some important logic gates like a universal gate. Ultimately the property of resistivity proves the law of Boolean logic of AND gate and universal logic gate, viz., NAND and NOR gate. All the electronic properties of the Boolean logic gate are explored based on the first principle approach by non-equilibrium Green's function coupled with density functional theory in room temperature.
- Published
- 2021
- Full Text
- View/download PDF
22. Lung Nodule Detection from Feature Engineering to Deep Learning in Thoracic CT Images: a Comprehensive Review.
- Author
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Halder A, Dey D, and Sadhu AK
- Subjects
- Humans, Lung, Tomography, X-Ray Computed, Deep Learning, Lung Neoplasms diagnostic imaging, Solitary Pulmonary Nodule diagnostic imaging
- Abstract
This paper presents a systematic review of the literature focused on the lung nodule detection in chest computed tomography (CT) images. Manual detection of lung nodules by the radiologist is a sequential and time-consuming process. The detection is subjective and depends on the radiologist's experiences. Owing to the variation in shapes and appearances of a lung nodule, it is very difficult to identify the proper location of the nodule from a huge number of slices generated by the CT scanner. Small nodules (< 10 mm in diameter) may be missed by this manual detection process. Therefore, computer-aided diagnosis (CAD) system acts as a "second opinion" for the radiologists, by making final decision quickly with higher accuracy and greater confidence. The goal of this survey work is to present the current state of the artworks and their progress towards lung nodule detection to the researchers and readers in this domain. This review paper has covered the published works from 2009 to April 2018. Different nodule detection approaches are described elaborately in this work. Recently, it is observed that deep learning (DL)-based approaches are applied extensively for nodule detection and characterization. Therefore, emphasis has been given to convolutional neural network (CNN)-based DL approaches by describing different CNN-based networks.
- Published
- 2020
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23. The association between epicardial adipose tissue thickness around the right ventricular free wall evaluated by transthoracic echocardiography and left atrial appendage function.
- Author
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Yamaguchi S, Otaki Y, Tamarappoo B, Yoshida J, Ikenaga H, Friedman J, Berman D, Dey D, and Shiota T
- Subjects
- Adipose Tissue physiopathology, Aged, Aged, 80 and over, Atrial Appendage physiopathology, Atrial Fibrillation physiopathology, Female, Humans, Male, Middle Aged, Pericardium, Predictive Value of Tests, Reproducibility of Results, Retrospective Studies, Adipose Tissue diagnostic imaging, Adiposity, Atrial Appendage diagnostic imaging, Atrial Fibrillation diagnostic imaging, Atrial Function, Left, Echocardiography, Three-Dimensional, Echocardiography, Transesophageal
- Abstract
Epicardial adipose tissue (EAT) is associated with the development of atrial fibrillation (AF). EAT thickness identified on transthoracic echocardiography (TTE). The relationship between EAT volume and left atrial appendage (LAA) function is not well-known. We aimed to investigate the associations between EAT thickness and LAA emptying flow velocity and LAA orifice area. This single-center retrospective study enrolled 202 patients who underwent both TTE and transesophageal echocardiography (TEE). EAT thickness was measured on TTE in parasternal long-axis view. We measured LAA orifice areas in 41 patients with 3-dimensional TEE data. Spearman's correlation coefficient was used to determine the relationships between EAT thickness and LAA emptying flow velocity and LAA orifice area. We created a receiver operating characteristic curve for low LAA emptying flow velocity (< 20 cm/s) and determined the best cutoff for EAT thickness according to the maximum Youden index. There was a significant negative correlation between EAT thickness and LAA emptying flow velocity (ρ = - 0.56, P < 0.001) and a significant positive correlation between EAT thickness and LAA orifice area (ρ = 0.38, P = 0.014). The best EAT thickness cutoff value for low LAA emptying flow velocity was > 5.1 mm (c-statistics, 75.7%). A thickened EATT was associated with low LAA emptying flow velocity, which increases the risk of thromboembolic phenomena in the presence of AF.
- Published
- 2020
- Full Text
- View/download PDF
24. Epidemiologically and Socio-economically Optimal Policies via Bayesian Optimization.
- Author
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Chandak A, Dey D, Mukhoty B, and Kar P
- Abstract
Mass public quarantining, colloquially known as a lock-down , is a non-pharmaceutical intervention to check spread of disease. This paper presents ESOP (Epidemiologically and Socio-economically Optimal Policies), a novel application of active machine learning techniques using Bayesian optimization, that interacts with an epidemiological model to arrive at lock-down schedules that optimally balance public health benefits and socio-economic downsides of reduced economic activity during lock-down periods. The utility of ESOP is demonstrated using case studies with VIPER (Virus-Individual-Policy-EnviRonment), a stochastic agent-based simulator that this paper also proposes. However, ESOP is flexible enough to interact with arbitrary epidemiological simulators in a black-box manner, and produce schedules that involve multiple phases of lock-downs., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© Indian National Academy of Engineering 2020.)
- Published
- 2020
- Full Text
- View/download PDF
25. Perivascular Adipose Tissue and Coronary Atherosclerosis: from Biology to Imaging Phenotyping.
- Author
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Lin A, Dey D, Wong DTL, and Nerlekar N
- Subjects
- Humans, Inflammation, Adipose Tissue immunology, Computed Tomography Angiography methods, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease immunology, Coronary Vessels diagnostic imaging, Coronary Vessels immunology, Coronary Vessels pathology
- Abstract
Purpose of Review: Perivascular adipose tissue (PVAT) has a complex, bidirectional relationship with the vascular wall. In disease states, PVAT secretes pro-inflammatory adipocytokines which may contribute to atherosclerosis. Recent evidence demonstrates that pericoronary adipose tissue (PCAT) may also function as a sensor of coronary inflammation. This review details PVAT biology and its clinical translation to current imaging phenotyping., Recent Findings: PCAT attenuation derived from routine coronary computed tomography (CT) angiography is a novel noninvasive imaging biomarker of coronary inflammation. Pro-inflammatory cytokines released from the arterial wall diffuse directly into the surrounding PCAT and inhibit adipocyte lipid accumulation in a paracrine manner. This can be detected as an increased PCAT CT attenuation, a metric which associates with high-risk plaque features and independently predicts cardiac mortality. There is also evidence that PCAT attenuation relates to coronary plaque progression and is modified by systemic anti-inflammatory therapies. Due to its proximity to the coronary arteries, PCAT has emerged as an important fat depot in cardiovascular research. PCAT CT attenuation has the potential to improve cardiovascular risk stratification, and future clinical studies should examine its role in guiding targeted medical therapy.
- Published
- 2019
- Full Text
- View/download PDF
26. Cardiac CT: Technological Advances in Hardware, Software, and Machine Learning Applications.
- Author
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Commandeur F, Goeller M, and Dey D
- Abstract
Purpose of Review: Multidetector row computed tomography (CT) allows noninvasive imaging of the heart and coronary arteries. The purpose of this review is to briefly summarize recent advances in CT hardware and software technology, and machine learning applications for cardiovascular imaging., Recent Findings: In the last decades, there have been significant improvements in CT hardware focusing on faster gantry rotation resulting in improved temporal resolution. Concurrent hardware improvements include improved spatial resolution and higher coverage of the patient, enabling faster acquisition. Advances in cardiac CT software include methods for measurement of noninvasive FFR, coronary plaque characterization, and adipose tissue characteristics around the heart. Machine learning approaches using cardiac CT have been shown to improve both risk of prognosis and lesion-specific ischemia., Summary: Recent advances in CT hardware and software have expanded the clinical utility of CT for cardiovascular imaging. In the next decades, continued advances can be anticipated in these areas, and in machine learning applications in cardiac CT, as they are incorporated into clinical routine for image acquisition, image analysis, and prediction of patient outcomes., Competing Interests: Conflict of Interest Damini Dey reports software licensing royalties from Cedars-Sinai Medical Center outside the submitted work. The other authors declare no conflicts of interest.
- Published
- 2018
- Full Text
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27. Dyspnea predicts mortality among patients undergoing coronary computed tomographic angiography.
- Author
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Nakanishi R, Gransar H, Rozanski A, Rana JS, Cheng VY, Thomson LEJ, Miranda-Peats R, Dey D, Hayes SW, Friedman JD, Min JK, and Berman DS
- Subjects
- Aged, Angina Pectoris mortality, Causality, Comorbidity, Female, Humans, Los Angeles epidemiology, Male, Middle Aged, Proportional Hazards Models, Coronary Angiography, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease mortality, Dyspnea mortality, Tomography, X-Ray Computed
- Abstract
The prognostic implications of dyspnea and typical angina in patients referred for coronary CT angiography have not been examined. We examined features associated with incident mortality risk among individuals undergoing coronary computed tomographic angiography (CCTA) presenting with dyspnea, typical angina, and neither of these symptoms. 1147 consecutive individuals without known CAD (mean 61 years, 61.6 %men) undergoing CCTA comprised the study population 132 with dyspnea, 218 with typical angina, and 797 without dyspnea or typical angina (reference group). Mortality risk in relation to dyspnea or typical angina was evaluated with multivariable Cox proportional hazards models compared to reference. In addition, the prognosis associated with dyspnea or typical angina was assessed among age matched subgroups. Patients with dyspnea had a greater prevalence of C70 % stenosis (p\0.001) and coronary segments with plaque (p = 0.02) compared to the other two groups. During a follow-up of 3.1 years, 52 individuals died. By multivariable Cox models, compared to patients in reference group, dyspnea patients experienced higher mortality (HR 2.0, 95 % CI 1.0–4.0, p = 0.049) while typical angina patients did not (HR 1.1, 95 % CI 0.6–2.3, p = 0.76). In the matched group, the patients with dyspnea (HR 2.2, 95 % CI 1.1–4.3, p = 0.03) still had significantly reduced survival compared to the other two groups, while those with typical angina did not (HR 1.2, 95 % CI 0.6–2.6,p = 0.62). Dyspnea is associated with increased mortality ate compared to patients with typical angina and those with neither of these symptoms among patients undergoing CCTA.
- Published
- 2016
- Full Text
- View/download PDF
28. First branchial cleft anomaly: clinical insight into its relevance in otolaryngology with pediatric considerations.
- Author
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Maithani T, Pandey A, Dey D, Bhardwaj A, and Singh VP
- Abstract
First branchial cleft anomalies (FBCA) represent a small subset of congenital malformations in neck. Prime objective of this study is to share our experience with FBCA, emphasize its relevance in otolaryngology and deal with its pediatric perspective. Embryology, pathologic anatomy and varied spectra of clinical presentations of FBCA are discussed. Along with this we have illustrated three different cases; all of them were of pediatric age group and were misdiagnosed by their treating specialists elsewhere. In this article we have also laid special emphasis on its pediatric considerations. FBCA are mostly misdiagnosed due to their unfamiliar clinical signs and symptoms. Swellings may masquerade as other neck masses. Majority of patients give a history of previous incision and drainage. While dealing with pediatric patients the important factors to be kept in mind are the age of child, superficial course of facial nerve, any associated agenesis of parotid gland. Alteration in surgical technique may be required in children. A thorough medical examination with high index of clinical suspicion should be kept in mind while dealing with such anomalies. Owing to their complex presentation and close relation with facial nerve they are challenging lesions for surgeons.
- Published
- 2014
- Full Text
- View/download PDF
29. Mechanical property characterization of bilayered tablets using nondestructive air-coupled acoustics.
- Author
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Akseli I, Dey D, and Cetinkaya C
- Subjects
- Dosage Forms, Excipients, Lasers, Pressure, Vibration, Acoustics, Air, Pharmaceutical Preparations chemistry, Tablets chemistry, Ultrasonics
- Abstract
A noncontact/nondestructive air-coupled acoustic technique to be potentially used in mechanical property determination of bilayer tablets is presented. In the reported experiments, a bilayer tablet is vibrated via an acoustic field of an air-coupled transducer in a frequency range sufficiently high to excite several vibrational modes (harmonics) of the tablet. The tablet vibrational transient responses at a number of measurement points on the tablet are acquired by a laser vibrometer in a noncontact manner. An iterative computational procedure based on the finite element method is utilized to extract the Young's modulus, the Poisson's ratio, and the mass density values of each layer material of a bilayer tablet from a subset of the measured resonance frequencies. For verification purposes, a contact ultrasonic technique based on the time-of-flight data of the longitudinal (pressure) and transverse (shear) acoustic waves in each layer of a bilayer tablet is also utilized. The extracted mechanical properties from the air-coupled acoustic data agree well with those determined from the contact ultrasonic measurements. The mechanical properties of solid oral dosage forms have been shown to impact its mechanical integrity, disintegration profile and the release rate of the drug in the digestive tract, thus potentially affecting its therapeutic response. The presented nondestructive technique provides greater insight into the mechanical properties of the bilayer tablets and has the potential to identify quality and performance problems related to the mechanical properties of the bilayer tablets early on the production process and, consequently, reduce associated cost and material waste.
- Published
- 2010
- Full Text
- View/download PDF
30. A Lupinoside prevented fatty acid induced inhibition of insulin sensitivity in 3T3 L1 adipocytes.
- Author
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Dey D, Pal BC, Biswas T, Roy SS, Bandyopadhyay A, Mandal SK, Giri BB, and Bhattacharya S
- Subjects
- 3T3-L1 Cells, Animals, Deoxyglucose metabolism, Glucose Transporter Type 4 metabolism, Green Fluorescent Proteins metabolism, Insulin pharmacology, Male, Mice, Phytotherapy, Plant Extracts chemistry, Plant Extracts isolation & purification, Rats, Rats, Sprague-Dawley, Recombinant Fusion Proteins metabolism, Saponins chemistry, Saponins isolation & purification, Signal Transduction drug effects, Adipocytes drug effects, Adipocytes metabolism, Insulin Resistance physiology, Palmitates pharmacology, Plant Extracts pharmacology, Pueraria metabolism, Saponins pharmacology
- Abstract
The decrease in insulin sensitivity to target tissues or insulin resistance leads to type 2 diabetes mellitus, an insidious disease threatening global health. Numerous evidences made free fatty acids (FFAs) responsible for insulin resistance and type 2 diabetes. We demonstrate here that the damage of insulin acitivity by a free fatty acid, palmitate could be prevented by a lupinoside. An incubation of 3T3 L1 adipocytes with a FFA i.e. palmitate inhibited insulin stimulated uptake of (3)H-2 deoxyglucose (2 DOG) significantly. Addition of a lupinoside purified from Pueraria tuberosa, lupinoside PA(4) (LPA(4)) strongly prevented this inhibition. We then examined insulin signaling pathway where palmitate significantly inhibited insulin stimulated phosphorylation of Insulin receptor tyrosine kinase, IRS 1and PI3 kinase, PDK1 and Akt/PKB. LPA(4) rescued this inhibition of signaling molecule by palmitate. Insulin mediated translocation of Glut4, the glucose transporter in insulin target cells, was effectively blocked by palmitate while, LPA(4) waived this block. Administration of LPA(4) to nutritionally induced diabetic rats significantly reduced the increase in plasma glucose. All these indicate LPA(4) to be a potentially therapeutic agent for insulin resistance and type 2 diabetes.
- Published
- 2007
- Full Text
- View/download PDF
31. A comparison of frailty and other models for bivariate survival data.
- Author
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Sahu SK and Dey DK
- Subjects
- Bayes Theorem, Humans, Markov Chains, Multiple Organ Failure physiopathology, Multivariate Analysis, Models, Statistical, Survival Analysis
- Abstract
Multivariate survival data arise when each study subject may experience multiple events or when study subjects are clustered into groups. Statistical analyses of such data need to account for the intra-cluster dependence through appropriate modeling. Frailty models are the most popular for such failure time data. However, there are other approaches which model the dependence structure directly. In this article, we compare the frailty models for bivariate data with the models based on bivariate exponential and Weibull distributions. Bayesian methods provide a convenient paradigm for comparing the two sets of models we consider. Our techniques are illustrated using two examples. One simulated example demonstrates model choice methods developed in this paper and the other example, based on a practical data set of onset of blindness among patients with diabetic Retinopathy, considers Bayesian inference using different models.
- Published
- 2000
- Full Text
- View/download PDF
32. A Weibull regression model with gamma frailties for multivariate survival data.
- Author
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Sahu SK, Dey DK, Aslanidou H, and Sinha D
- Subjects
- Bayes Theorem, Humans, Kidney Diseases etiology, Life Tables, Likelihood Functions, Markov Chains, Monte Carlo Method, Multivariate Analysis, Proportional Hazards Models, Regression Analysis, Survival Analysis
- Abstract
Frequently in the analysis of survival data, survival times within the same group are correlated due to unobserved co-variates. One way these co-variates can be included in the model is as frailties. These frailty random block effects generate dependency between the survival times of the individuals which are conditionally independent given the frailty. Using a conditional proportional hazards model, in conjunction with the frailty, a whole new family of models is introduced. By considering a gamma frailty model, often the issue is to find an appropriate model for the baseline hazard function. In this paper a flexible baseline hazard model based on a correlated prior process is proposed and is compared with a standard Weibull model. Several model diagnostics methods are developed and model comparison is made using recently developed Bayesian model selection criteria. The above methodologies are applied to the McGilchrist and Aisbett (1991) kidney infection data and the analysis is performed using Markov Chain Monte Carlo methods.
- Published
- 1997
- Full Text
- View/download PDF
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