131 results on '"Das HK"'
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2. A Heuristic Algorithm for solving Integer Linear Programming Problem and Unveiling the Applications
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Dhar, Abir Sutra, primary and Das, HK, primary
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- 2020
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3. An Algorithmic Procedure for Finding Nash Equilibrium
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Das, HK, primary and Saha, T, primary
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- 2020
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4. Potentials of coconut (Cocos nucifera) based agroforestry system in soil quality management in coastal Odisha
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Panda, NK, primary, Sarangi, SK, additional, Subudhi, SN, additional, and Das, HK, additional
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- 2020
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5. Capacity building of primary care physicians of the tea garden hospitals in Dibrugarh, Assam: A demonstration project
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Singh, Shalini, primary, Hariprasad, Roopa, additional, John, Amrita, additional, Das, HK, additional, Bora, Kaustubh, additional, Singh, Lucky, additional, Khaund, Purnananda, additional, and Hussain, Aizaz, additional
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- 2020
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6. A Review on the Proposed Quasi-Concave Quadratic Programming Problems with Bounded Variable: by Counter-example, by Computer Algebra
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Das, HK, primary
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- 2017
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7. A Procedure for Solving Quadratic Programming Problems
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Das, HK, primary
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- 2017
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8. A New Decomposition-Based Pricing Technique For Solving Large-Scale Mixed IP with a Computer Technique
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Islam, A, primary, Hasan, M Babul, primary, and Das, HK, primary
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- 2016
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9. An Algorithmic Technique for Solving Non-Linear Programming and Quadratic Programming Problems
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Das, HK, primary and Hasan, M Babul, primary
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- 2016
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10. A Study on 1-D Simplex Search Algorithm with its Numerical Experiments Through Computer Algebra
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Das, HK, primary, Saha, Tapash, primary, and Hasan, M Babul, primary
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- 2015
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11. An Improved Decomposition Approach and its Computational Technique for Analyzing Primal-Dual Relationship in LP & LFP Problems
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Das, HK, primary and Hasan, M Babul, primary
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- 2014
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12. Anaesthesia for autotransplantation after extracorporeal nephron sparing surgery for bilateral giant renal angiomyolipoma
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Rajmohan, Nisha, primary, Neeta, S, additional, and Das, HK, additional
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- 2014
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13. A Generalized Computer Technique for Solving Unconstrained Non-Linear Programming Problems
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Das, HK, primary and Hasan, MB, primary
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- 2013
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14. Exploring the dynamics of monkeypox transmission with data-driven methods and a deterministic model.
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Das HK
- Abstract
Introduction: Mpox (formerly monkeypox) is an infectious disease that spreads mostly through direct contact with infected animals or people's blood, bodily fluids, or cutaneous or mucosal lesions. In light of the global outbreak that occurred in 2022-2023, in this paper, we analyzed global Mpox univariate time series data and provided a comprehensive analysis of disease outbreaks across the world, including the USA with Brazil and three continents: North America, South America, and Europe. The novelty of this study is that it delved into the Mpox time series data by implementing the data-driven methods and a mathematical model concurrently-an aspect not typically addressed in the existing literature. The study is also important because implementing these models concurrently improved our predictions' reliability for infectious diseases., Methods: We proposed a traditional compartmental model and also implemented deep learning models (1D- convolutional neural network (CNN), long-short term memory (LSTM), bidirectional LSTM (BiLSTM), hybrid CNN-LSTM, and CNN-BiLSTM) as well as statistical time series models: autoregressive integrated moving average (ARIMA) and exponential smoothing on the Mpox data. We also employed the least squares method fitting to estimate the essential epidemiological parameters in the proposed deterministic model., Results: The primary finding of the deterministic model is that vaccination rates can flatten the curve of infected dynamics and influence the basic reproduction number. Through the numerical simulations, we determined that increased vaccination among the susceptible human population is crucial to control disease transmission. Moreover, in case of an outbreak, our model showed the potential for epidemic control by adjusting the key epidemiological parameters, namely the baseline contact rate and the proportion of contacts within the human population. Next, we analyzed data-driven models that contribute to a comprehensive understanding of disease dynamics in different locations. Additionally, we trained models to provide short-term (eight-week) predictions across various geographical locations, and all eight models produced reliable results., Conclusion: This study utilized a comprehensive framework to investigate univariate time series data to understand the dynamics of Mpox transmission. The prediction showed that Mpox is in its die-out situation as of July 29, 2023. Moreover, the deterministic model showed the importance of the Mpox vaccination in mitigating the Mpox transmission and highlighted the significance of effectively adjusting key epidemiological parameters during outbreaks, particularly the contact rate in high-risk groups., Competing Interests: The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Das.)
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- 2024
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15. Anxiety, depression and social support of LGBTIQ during COVID-19 in Kerala, India.
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Das HK and Govindappa L
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- Humans, Depression epidemiology, Anxiety epidemiology, Anxiety Disorders epidemiology, Social Support, Stress, Psychological epidemiology, COVID-19 epidemiology, COVID-19 psychology
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Background: It is reported that the marginalised and underprivileged sections suffer bitter consequences in the event of calamities and pandemics. The present study aims at assessing the level of anxiety, depression and social support of the LGBTIQ communities during the COVID-19. Since the 'LGBTIQ' community is an integral part of society, it is necessary to study these psychological dimensions in the face of multiple waves of the pandemic in the country., Aim: The study aims to measure the anxiety, depression and social support of LGBTIQ during COVID-19 in Kerala., Method: The study followed descriptive research design and using snowball sampling, total of 106 respondents were interviewed from the urban and rural areas of Kerala. The researchers used the 'DASS21' to assess anxiety and depression and the Multidimensional Scale of Perceived Social Support to assess social support., Results: Approximately half (44.3%) of the participants were experiencing severe or extremely severe levels of depression. At the same time, many of them had episodes of anxiety disorder at much higher levels (41.5%) than the other members of society. Perceived social support was negatively correlated with depression, anxiety and stress, while depression, anxiety and stress showed a positive correlation with each other., Conclusion: Common mental health problems such as anxiety, depression and stress were largely prevalent in the LGBTIQ community during COVID-19, who found the social support inadequate and suffered from other social and economic problems. There is a need to address these issues among this population., Competing Interests: Conflict of interestThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2023
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16. Metabolic non-communicable disease health report of India: the ICMR-INDIAB national cross-sectional study (ICMR-INDIAB-17).
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Anjana RM, Unnikrishnan R, Deepa M, Pradeepa R, Tandon N, Das AK, Joshi S, Bajaj S, Jabbar PK, Das HK, Kumar A, Dhandhania VK, Bhansali A, Rao PV, Desai A, Kalra S, Gupta A, Lakshmy R, Madhu SV, Elangovan N, Chowdhury S, Venkatesan U, Subashini R, Kaur T, Dhaliwal RS, and Mohan V
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- Adult, Humans, Cross-Sectional Studies, Urban Population, Rural Population, India epidemiology, Obesity, Prevalence, Risk Factors, Prediabetic State epidemiology, Noncommunicable Diseases epidemiology, Diabetes Mellitus epidemiology, Diabetes Mellitus therapy, Hypertension epidemiology, Dyslipidemias epidemiology
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Background: Non-communicable disease (NCD) rates are rapidly increasing in India with wide regional variations. We aimed to quantify the prevalence of metabolic NCDs in India and analyse interstate and inter-regional variations., Methods: The Indian Council of Medical Research-India Diabetes (ICMR-INDIAB) study, a cross-sectional population-based survey, assessed a representative sample of individuals aged 20 years and older drawn from urban and rural areas of 31 states, union territories, and the National Capital Territory of India. We conducted the survey in multiple phases with a stratified multistage sampling design, using three-level stratification based on geography, population size, and socioeconomic status of each state. Diabetes and prediabetes were diagnosed using the WHO criteria, hypertension using the Eighth Joint National Committee guidelines, obesity (generalised and abdominal) using the WHO Asia Pacific guidelines, and dyslipidaemia using the National Cholesterol Education Program-Adult Treatment Panel III guidelines., Findings: A total of 113 043 individuals (79 506 from rural areas and 33 537 from urban areas) participated in the ICMR-INDIAB study between Oct 18, 2008 and Dec 17, 2020. The overall weighted prevalence of diabetes was 11·4% (95% CI 10·2-12·5; 10 151 of 107 119 individuals), prediabetes 15·3% (13·9-16·6; 15 496 of 107 119 individuals), hypertension 35·5% (33·8-37·3; 35 172 of 111 439 individuals), generalised obesity 28·6% (26·9-30·3; 29 861 of 110 368 individuals), abdominal obesity 39·5% (37·7-41·4; 40 121 of 108 665 individuals), and dyslipidaemia 81·2% (77·9-84·5; 14 895 of 18 492 of 25 647). All metabolic NCDs except prediabetes were more frequent in urban than rural areas. In many states with a lower human development index, the ratio of diabetes to prediabetes was less than 1., Interpretation: The prevalence of diabetes and other metabolic NCDs in India is considerably higher than previously estimated. While the diabetes epidemic is stabilising in the more developed states of the country, it is still increasing in most other states. Thus, there are serious implications for the nation, warranting urgent state-specific policies and interventions to arrest the rapidly rising epidemic of metabolic NCDs in India., Funding: Indian Council of Medical Research and Department of Health Research, Ministry of Health and Family Welfare, Government of India., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
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- 2023
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17. Evaluation of Madras Diabetes Research Foundation-Indian Diabetes Risk Score in detecting undiagnosed diabetes in the Indian population: Results from the Indian Council of Medical Research-INdia DIABetes population-based study (INDIAB-15).
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Deepa M, Elangovan N, Venkatesan U, Das HK, Jampa L, Adhikari P, Joshi PP, Budnah RO, Suokhrie V, John M, Tobgay KJ, Subashini R, Pradeepa R, Anjana RM, Mohan V, Kaur T, and Dhaliwal RS
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- Male, Female, Humans, India epidemiology, Risk Factors, Diabetes Mellitus, Type 2 diagnosis, Diabetes Mellitus, Type 2 epidemiology, Diabetes Complications, Biomedical Research, Diabetes Mellitus diagnosis, Diabetes Mellitus epidemiology
- Abstract
Background & Objectives: Screening of individuals for early detection and identification of undiagnosed diabetes can help in reducing the burden of diabetic complications. This study aimed to evaluate the performance of Madras Diabetes Research Foundation (MDRF)-Indian Diabetes Risk Score (IDRS) to screen for undiagnosed type 2 diabetes in a large representative population in India., Methods: Data were acquired from the Indian Council of Medical Research-INdia DIABetes (ICMR-INDIAB) study, a large national survey that included both urban and rural populations from 30 states/union territories in India. Stratified multistage design was followed to obtain a sample of 113,043 individuals (94.2% response rate). MDRF-IDRS used four simple parameters, viz. age, waist circumference, family history of diabetes and physical activity to detect undiagnosed diabetes. Receiver operating characteristic (ROC) with area under the curve (AUC) was used to assess the performance of MDRF-IDRS., Results: We identified that 32.4, 52.7 and 14.9 per cent of the general population were under high-, moderate- and low-risk category of diabetes. Among the newly diagnosed individuals with diabetes [diagnosed by oral glucose tolerance test (OGTT)], 60.2, 35.9 and 3.9 per cent were identified under high-, moderate- and low-risk categories of IDRS. The ROC-AUC for the identification of diabetes was 0.697 (95% confidence interval: 0.684-0.709) for urban population and 0.694 (0.684-0.704) for rural, as well as 0.693 (0.682-0.705) for males and 0.707 (0.697-0.718) for females. MDRF-IDRS performed well when the population were sub-categorized by state or by regions., Interpretation & Conclusions: Performance of MDRF-IDRS is evaluated across the nation and is found to be suitable for easy and effective screening of diabetes in Asian Indians.
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- 2023
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18. Suramin, penciclovir, and anidulafungin exhibit potential in the treatment of COVID-19 via binding to nsp12 of SARS-CoV-2.
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Dey SK, Saini M, Dhembla C, Bhatt S, Rajesh AS, Anand V, Das HK, and Kundu S
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- Humans, Anidulafungin, Suramin, Molecular Docking Simulation, Antiviral Agents chemistry, SARS-CoV-2, COVID-19
- Abstract
COVID-19, for which no confirmed therapeutic agents are available, has claimed over 48,14,000 lives globally. A feasible and quicker method to resolve this problem may be 'drug repositioning'. We investigated selected FDA and WHO-EML approved drugs based on their previously promising potential as antivirals, antibacterials or antifungals. These drugs were docked onto the nsp12 protein, which reigns the RNA-dependent RNA polymerase activity of SARS-CoV-2, a key therapeutic target for coronaviruses. Docked complexes were reevaluated using MM-GBSA analysis and the top three inhibitor-protein complexes were subjected to 100 ns long molecular dynamics simulation followed by another round of MM-GBSA analysis. The RMSF plots, binding energies and the mode of physicochemical interaction of the active site of the protein with the drugs were evaluated. Suramin, Penciclovir, and Anidulafungin were found to bind to nsp12 with similar binding energies as that of Remdesivir, which has been used as a therapy for COVID-19. In addition, recent experimental evidences indicate that these drugs exhibit antiviral efficacy against SARS-CoV-2. Such evidence, along with the significant and varied physical interactions of these drugs with the key viral enzyme outlined in this investigation, indicates that they might have a prospective therapeutic potential in the treatment of COVID-19 as monotherapy or combination therapy with Remdesivir.
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- 2022
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19. HOXA5 Expression Is Elevated in Breast Cancer and Is Transcriptionally Regulated by Estradiol.
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Hussain I, Deb P, Chini A, Obaid M, Bhan A, Ansari KI, Mishra BP, Bobzean SA, Udden SMN, Alluri PG, Das HK, Brothers RM, Perrotti LI, and Mandal SS
- Abstract
HOXA5 is a homeobox-containing gene associated with the development of the lung, gastrointestinal tract, and vertebrae. Here, we investigate potential roles and the gene regulatory mechanism in HOXA5 in breast cancer cells. Our studies demonstrate that HOXA5 expression is elevated in breast cancer tissues and in estrogen receptor (ER)-positive breast cancer cells. HOXA5 expression is critical for breast cancer cell viability. Biochemical studies show that estradiol (E2) regulates HOXA5 gene expression in cultured breast cancer cells in vitro . HOXA5 expression is also upregulated in vivo in the mammary tissues of ovariectomized female rats. E2-induced HOXA5 expression is coordinated by ERs. Knockdown of either ERα or ERβ downregulated E2-induced HOXA5 expression. Additionally, ER co-regulators, including CBP/p300 (histone acetylases) and MLL-histone methylases (MLL2, MLL3), histone acetylation-, and H3K4 trimethylation levels are enriched at the HOXA5 promoter in present E2. In summary, our studies demonstrate that HOXA5 is overexpressed in breast cancer and is transcriptionally regulated via estradiol in breast cancer cells., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Hussain, Deb, Chini, Obaid, Bhan, Ansari, Mishra, Bobzean, Udden, Alluri, Das, Brothers, Perrotti and Mandal.)
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- 2020
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20. Capacity building of primary care physicians of the tea garden hospitals in Dibrugarh, Assam: A demonstration project.
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Hariprasad R, John A, Das HK, Bora K, Singh L, Khaund P, Hussain A, and Singh S
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Background: The three most commonly occurring cancers in India are those of the breast, uterine cervix, and lip or oral cavity, together accounting for approximately 34% of all cancers. All the three cancers are amenable to prevention, early detection, and treatment through which the morbidity and mortality due to these cancers can be reduced. This pilot study was conducted to assess the operational feasibility of the national cancer screening guidelines., Method: This study was conducted in the Dibrugarh district of Assam in seven tea garden hospitals which serve as the primary health centers for the tea estate population in the Northeast region of India. The study intervention was a three-day training package designed to train primary care physicians in population-based screening for oral, breast, and cervical cancers. Knowledge evaluation and skill assessment were performed with a validated questionnaire and checklist, respectively., Results: Pre and posttraining knowledge assessment showed significant gain in the knowledge levels of the participants in all topics. The greatest knowledge increase was seen in breast cancer (96.3%), followed by cervical cancer (57.5%), oral cancer (35.5%) and general cancer-related information (16.7%). The skill assessment done for each participant individually at the end of the training indicated a need for retraining all participants in breast cancer screening., Conclusion: The learnings from this study will be of great help in scaling up the capacity building programme for cancer screening when the nation-wide population-based cancer screening programme will be rolled out in the country., Competing Interests: There are no conflicts of interest., (Copyright: © 2020 Journal of Family Medicine and Primary Care.)
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- 2020
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21. Inhibition of p-mTOR represses transcription of PS1 and Notch 1-signaling.
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Das HK and Hontiveros SS
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- Adaptor Proteins, Signal Transducing metabolism, Blotting, Western, Cell Cycle Proteins metabolism, Cell Line, Tumor, Humans, Immunosuppressive Agents pharmacology, Presenilin-1 metabolism, Reverse Transcriptase Polymerase Chain Reaction, Ribosomal Protein S6 Kinases, 70-kDa metabolism, TOR Serine-Threonine Kinases metabolism, Transcription Factor HES-1 genetics, Transcription Factor HES-1 metabolism, Gene Expression Regulation, Neoplastic drug effects, Presenilin-1 genetics, Receptor, Notch1 metabolism, Signal Transduction drug effects, Sirolimus pharmacology, TOR Serine-Threonine Kinases antagonists & inhibitors
- Abstract
Presenilin-1 (PS1) protein is the catalytic subunit of the gamma-secretase, and participates in the processing of beta-amyloid precursor protein (APP) to produce Abeta peptide and Notch 1 receptor to release Notch intracellular domain (NICD) in the cytoplasm. NICD migrates to the nucleus and causes Notch signaling by increasing the expression of the Hes1 gene. The mammalian target of rapamycin (mTOR) controls cellular homeostasis, and its activity is inhibited by rapamycin. The buildup of Abeta increases the mTOR signaling, whereas decreasing mTOR signaling reduces Abeta levels suggesting an interrelationship between mTOR signaling and Abeta. Administration of rapamycin in 3XTg-AD mouse model of Alzheimer's disease (AD) rescues cognitive deficits and ameliorates Abeta and Tau pathology. We have dissected the mechanisms by which rapamycin inhibits PS1 expression and Notch1 signaling. Our results demonstrated that rapamycin efficiently suppressed phosphorylation of mTOR (p-mTOR), and decreased expression of PS1-mRNA as well as p-p70S6K1, 4EBP1, PS1, NICD, and Hes1 protein levels. Therefore, rapamycin decreased PS1 protein levels and Notch 1 processing by inhibiting PS1 transcription.
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- 2020
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22. Inhibition of p-mTOR represses PS1 transcription by reducing p-JNK.
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Das HK and Hontiveros SS
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- Anthracenes pharmacology, Blotting, Western, Cell Line, Tumor, Humans, Immunosuppressive Agents pharmacology, JNK Mitogen-Activated Protein Kinases antagonists & inhibitors, JNK Mitogen-Activated Protein Kinases metabolism, Phosphorylation drug effects, Presenilin-1 metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Signal Transduction drug effects, Signal Transduction genetics, TOR Serine-Threonine Kinases metabolism, Transcription, Genetic drug effects, Gene Expression Regulation, Neoplastic drug effects, JNK Mitogen-Activated Protein Kinases genetics, Presenilin-1 genetics, Sirolimus pharmacology, TOR Serine-Threonine Kinases antagonists & inhibitors
- Abstract
Presenilin-1 (PS1) is the catalytic subunit of gamma-secretase. PS1 cleaves beta-amyloid precursor protein (APP) to produce Abeta peptide and Notch 1 receptor to release Notch intracellular domain (NICD) in the cytoplasm. We have previously shown that rapamycin inhibits p-mTOR to repress PS1 transcription and Notch 1-signaling. But the exact mechanism by which rapamycin inhibits PS1 transcription is not known. We have also published that inhibition of basal activity of c-jun-NH2-terminal kinase (JNK) with JNK-specific inhibitor SP600125 represses PS1 transcription by reducing p-JNK and via p53 dependent mechanism. We now report that rapamycin inhibits the phosphorylation of both mTOR (p-mTOR) and JNK (p-JNK). It appears that rapamycin represses PS1 transcription by inhibiting the expression of p-JNK in SK-N-SH cells under non-stressed condition. Consequently, one of the mechanisms of inhibition of PS1 transcription by rapamycin is similar to the mechanism of repression of PS1 transcription by JNK-specific inhibitor SP600125. We also report that JNK-inhibitor SP6000125 decreases both p-JNK and p-mTOR protein levels. These results suggest that JNK and mTOR may potentially activate each other by mutual phosphorylation.
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- 2020
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23. Azotobacters as biofertilizer.
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Das HK
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- Ammonium Hydroxide metabolism, Gene Expression Regulation, Bacterial, Genes, Bacterial, Genes, Regulator, Genetic Engineering, Glucose 1-Dehydrogenase genetics, Glucose 1-Dehydrogenase metabolism, Glutamate-Ammonia Ligase genetics, Glutamate-Ammonia Ligase metabolism, Microorganisms, Genetically-Modified, Nitrogen metabolism, Nitrogen Fixation genetics, Nitrogenase genetics, Nitrogenase metabolism, Phosphates metabolism, Urea metabolism, Urease genetics, Urease metabolism, Azotobacter genetics, Azotobacter metabolism, Azotobacter vinelandii genetics, Azotobacter vinelandii metabolism, Bacterial Proteins genetics, Fertilizers microbiology, Transcription Factors genetics
- Abstract
Azotobacters have been used as biofertilizer since more than a century. Azotobacters fix nitrogen aerobically, elaborate plant hormones, solubilize phosphates and also suppress phytopathogens or reduce their deleterious effect. Application of wild type Azotobacters results in better yield of cereals like corn, wheat, oat, barley, rice, pearl millet and sorghum, of oil seeds like mustard and sunflower, of vegetable crops like tomato, eggplant, carrot, chillies, onion, potato, beans and sugar beet, of fruits like mango and sugar cane, of fiber crops like jute and cotton and of tree like oak. In addition to the structural genes of the enzyme nitrogenase and of other accessory proteins, A. vinelandii chromosomes contain the regulatory genes nifL and nifA. NifA must bind upstream of the promoters of all nif operons for enabling their expression. NifL on activation by oxygen or ammonium, interacts with NifA and neutralizes it. Nitrogen fixation has been enhanced by deletion of nifL and by bringing nifA under the control of a constitutive promoter, resulting in a strain that continues to fix nitrogen in presence of urea fertilizer. Additional copies of nifH (the gene for the Fe-protein of nitrogenase) have been introduced into A. vinelandii, thereby augmenting nitrogen fixation. The urease gene complex ureABC has been deleted, the ammonia transport gene amtB has been disrupted and the expression of the glutamine synthase gene has been regulated to enhance urea and ammonia excretion. Gluconic acid has been produced by introducing the glucose dehydrogenase gene, resulting in enhanced solubilization of phosphate., (© 2019 Elsevier Inc. All rights reserved.)
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- 2019
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24. Electro-Physiology of Coupling Model and Its Impact on Naja Kaouthia Venom Treated Sciatic Nerves of Toad.
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Das HK and Sahu PP
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- Action Potentials, Animals, Bufonidae, Demyelinating Diseases pathology, Electrophysiological Phenomena drug effects, Myelin Sheath drug effects, Myelin Sheath ultrastructure, Neural Conduction drug effects, Recovery of Function, Sciatic Nerve pathology, Demyelinating Diseases chemically induced, Elapid Venoms pharmacology, Sciatic Nerve drug effects
- Abstract
Demyelination in peripheral nerves causes dysfunction of slowing down and stoppage of nerve impulses causing many neurological diseases, such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. This paper aims to develop a recovery model having interaction of a demyelinated nerve with a normal myelinated nerve. We validated the model by coupling between peripheral nerve of toad (demyelinated with Naja kaouthia venom) and a normal nerve of toad. An increase in both nerve conduction velocity as well as compound action potential amplitude is observed in the repetition of the experiments indicating gradual recovery of the patients. The significance behind this work is to suppress the malfunctioning of the demyelinated nerve by the normal electro-physiological activity of the normal nerve for speedy recovery using coupling model. The recovery model will be used in the treatment of neurological disorders with the influence of normal neuro physiological properties of a normal adjacent nerve.
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- 2018
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25. Prevalence of diabetes and prediabetes in 15 states of India: results from the ICMR-INDIAB population-based cross-sectional study.
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Anjana RM, Deepa M, Pradeepa R, Mahanta J, Narain K, Das HK, Adhikari P, Rao PV, Saboo B, Kumar A, Bhansali A, John M, Luaia R, Reang T, Ningombam S, Jampa L, Budnah RO, Elangovan N, Subashini R, Venkatesan U, Unnikrishnan R, Das AK, Madhu SV, Ali MK, Pandey A, Dhaliwal RS, Kaur T, Swaminathan S, and Mohan V
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- Adult, Cross-Sectional Studies, Female, Humans, India epidemiology, Male, Middle Aged, Prevalence, Risk Factors, Rural Health, Rural Population, Urban Health, Urban Population, Diabetes Mellitus epidemiology, Prediabetic State epidemiology
- Abstract
Background: Previous studies have not adequately captured the heterogeneous nature of the diabetes epidemic in India. The aim of the ongoing national Indian Council of Medical Research-INdia DIABetes study is to estimate the national prevalence of diabetes and prediabetes in India by estimating the prevalence by state., Methods: We used a stratified multistage design to obtain a community-based sample of 57 117 individuals aged 20 years or older. The sample population represented 14 of India's 28 states (eight from the mainland and six from the northeast of the country) and one union territory. States were sampled in a phased manner: phase I included Tamil Nadu, Chandigarh, Jharkhand, and Maharashtra, sampled between Nov 17, 2008, and April 16, 2010; phase II included Andhra Pradesh, Bihar, Gujarat, Karnataka, and Punjab, sampled between Sept 24, 2012, and July 26, 2013; and the northeastern phase included Assam, Mizoram, Arunachal Pradesh, Tripura, Manipur, and Meghalaya, with sampling done between Jan 5, 2012, and July 3, 2015. Capillary oral glucose tolerance tests were used to diagnose diabetes and prediabetes in accordance with WHO criteria. Our methods did not allow us to differentiate between type 1 and type 2 diabetes. The prevalence of diabetes in different states was assessed in relation to socioeconomic status (SES) of individuals and the per-capita gross domestic product (GDP) of each state. We used multiple logistic regression analysis to examine the association of various factors with the prevalence of diabetes and prediabetes., Findings: The overall prevalence of diabetes in all 15 states of India was 7·3% (95% CI 7·0-7·5). The prevalence of diabetes varied from 4·3% in Bihar (95% CI 3·7-5·0) to 10·0% (8·7-11·2) in Punjab and was higher in urban areas (11·2%, 10·6-11·8) than in rural areas (5·2%, 4·9-5·4; p<0·0001) and higher in mainland states (8·3%, 7·9-8·7) than in the northeast (5·9%, 5·5-6·2; p<0·0001). Overall, 1862 (47·3%) of 3938 individuals identified as having diabetes had not been diagnosed previously. States with higher per-capita GDP seemed to have a higher prevalence of diabetes (eg, Chandigarh, which had the highest GDP of US$ 3433, had the highest prevalence of 13·6%, 12.8-15·2). In rural areas of all states, diabetes was more prevalent in individuals of higher SES. However, in urban areas of some of the more affluent states (Chandigarh, Maharashtra, and Tamil Nadu), diabetes prevalence was higher in people with lower SES. The overall prevalence of prediabetes in all 15 states was 10·3% (10·0-10·6). The prevalence of prediabetes varied from 6·0% (5·1-6·8) in Mizoram to 14·7% (13·6-15·9) in Tripura, and the prevalence of impaired fasting glucose was generally higher than the prevalence of impaired glucose tolerance. Age, male sex, obesity, hypertension, and family history of diabetes were independent risk factors for diabetes in both urban and rural areas., Interpretation: There are large differences in diabetes prevalence between states in India. Our results show evidence of an epidemiological transition, with a higher prevalence of diabetes in low SES groups in the urban areas of the more economically developed states. The spread of diabetes to economically disadvantaged sections of society is a matter of great concern, warranting urgent preventive measures., Funding: Indian Council of Medical Research and Department of Health Research, Ministry of Health and Family Welfare, Government of India., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
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- 2017
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26. An Environmentally Friendly Engineered Azotobacter Strain That Replaces a Substantial Amount of Urea Fertilizer while Sustaining the Same Wheat Yield.
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Bageshwar UK, Srivastava M, Pardha-Saradhi P, Paul S, Gothandapani S, Jaat RS, Shankar P, Yadav R, Biswas DR, Kumar PA, Padaria JC, Mandal PK, Annapurna K, and Das HK
- Abstract
In our endeavor to improve the nitrogen fixation efficiency of a soil diazotroph that would be unaffected by synthetic nitrogenous fertilizers, we have deleted a part of the negative regulatory gene nifL and constitutively expressed the positive regulatory gene nifA in the chromosome of Azotobacter chroococcum CBD15, a strain isolated from the local field soil. No antibiotic resistance gene or other foreign gene was present in the chromosome of the engineered strain. Wheat seeds inoculated with this engineered strain, which we have named Azotobacter chroococcum HKD15, were tested for 3 years in pots and 1 year in the field. The yield of wheat was enhanced by ∼60% due to inoculation of seeds by A. chroococcum HKD15 in the absence of any urea application. Ammonium only marginally affected acetylene reduction by the engineered Azotobacter strain. When urea was also applied, the same wheat yield could be sustained by using seeds inoculated with A. chroococcum HKD15 and using ∼85 kg less urea (∼40 kg less nitrogen) than the usual ∼257 kg urea (∼120 kg nitrogen) per hectare. Wheat plants arising from the seeds inoculated with the engineered Azotobacter strain exhibited far superior overall performance, had much higher dry weight and nitrogen content, and assimilated molecular
15 N much better. A nitrogen balance experiment also revealed much higher total nitrogen content. Indole-3-acetic acid (IAA) production by the wild type and that by the engineered strain were about the same. Inoculation of the wheat seeds with A. chroococcum HKD15 did not adversely affect the microbial population in the field rhizosphere soil. IMPORTANCE Application of synthetic nitrogenous fertilizers is a standard agricultural practice to augment crop yield. Plants, however, utilize only a fraction of the applied fertilizers, while the unutilized fertilizers cause grave environmental problems. Wild-type soil diazotrophic microorganisms cannot replace synthetic nitrogenous fertilizers, as these reduce atmospheric nitrogen very inefficiently and almost none at all in the presence of added nitrogenous fertilizers. If the nitrogen-fixing ability of soil diazotrophs could be improved and sustained even in the presence of synthetic nitrogenous fertilizers, then a mixture of the bacteria and a reduced quantity of chemical nitrogenous fertilizers could be employed to obtain the same grain yield but at a much-reduced environmental cost. The engineered Azotobacter strain that we have reported here has considerably enhanced nitrogen fixation and excretion abilities and can replace ∼85 kg of urea per hectare but sustain the same wheat yield, if the seeds are inoculated with it before sowing., (Copyright © 2017 American Society for Microbiology.)- Published
- 2017
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27. The Role of Presenilin-1 in the Excitotoxicity of Ethanol Withdrawal.
- Author
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Jung ME, Metzger DB, and Das HK
- Subjects
- Amyloid Precursor Protein Secretases antagonists & inhibitors, Animals, Body Weight drug effects, Cell Death drug effects, Cell Line, Cell Survival drug effects, Enzyme Inhibitors pharmacology, Ethanol blood, Gene Expression Regulation, Enzymologic drug effects, Glutamic Acid metabolism, Glutamic Acid pharmacology, Hippocampus drug effects, Hippocampus metabolism, Male, Mice, Mitogen-Activated Protein Kinase 14 metabolism, Prefrontal Cortex drug effects, Prefrontal Cortex metabolism, Rats, Rats, Sprague-Dawley, Substance Withdrawal Syndrome pathology, Ethanol pharmacology, Presenilin-1 metabolism, Substance Withdrawal Syndrome metabolism
- Abstract
Presenilin-1 (PS1) is a core component of γ-secretase that is involved in neurodegeneration. We have previously shown that PS1 interacts with a mitogen-activated protein kinase [(MAPK) jun-NH2-terminal-kinase], and another MAPK (p38) is activated by ethanol withdrawal (EW), abrupt termination from chronic ethanol exposure. EW is excitotoxic in nature, induces glutamate upregulation, and provokes neuronal damage. Here, we explored a potential mechanistic pathway involving glutamate, p38 (p38α isozyme), and PS1 that may mediate EW-induced excitotoxic stress. We used the prefrontal cortex of male rats withdrawn from a chronic ethanol diet. Additionally, we used ethanol-withdrawn HT22 cells (mouse hippocampal) treated with the inhibitor of glutamate receptors [dizocilpine (MK-801)], p38α (SB203580; 4-[4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-1H-imidazol-5-yl]pyridine), or γ-secretase [N-[N- (3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT)] during EW. Separately, ethanol-free HT22 cells were exposed to glutamate with or without SB203580 or DAPT. Protein levels, mRNA levels, and cell viability were assessed using immunoblotting, qualitative polymerase chain reaction, and calcein assay, respectively. The prefrontal cortex of ethanol-withdrawn rats or HT22 cells showed an increase in PS1 and p38α, which was attenuated by MK-801 and SB203580, but mimicked by glutamate treatment to ethanol-free HT22 cells. DAPT attenuated the toxic effect of EW or glutamate on HT22 cells. These results suggest that PS1 expression is triggered by glutamate through p38α, contributing to the excitotoxic stimulus of EW., (Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.)
- Published
- 2016
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28. Quantifying Demyelination in NK venom treated nerve using its electric circuit model.
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Das HK, Das D, Doley R, and Sahu PP
- Subjects
- Animals, Anura, Axons metabolism, Cell Membrane drug effects, Cell Membrane metabolism, Ion Channels metabolism, Neural Conduction drug effects, Phospholipases A2 metabolism, Sciatic Nerve drug effects, Demyelinating Diseases pathology, Elapid Venoms pharmacology, Electricity, Models, Neurological, Sciatic Nerve pathology
- Abstract
Reduction of myelin in peripheral nerve causes critical demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. Clinical monitoring of these diseases requires rapid and non-invasive quantification of demyelination. Here we have developed formulation of nerve conduction velocity (NCV) in terms of demyelination considering electric circuit model of a nerve having bundle of axons for its quantification from NCV measurements. This approach has been validated and demonstrated with toad nerve model treated with crude Naja kaouthia (NK) venom and also shows the effect of Phospholipase A2 and three finger neurotoxin from NK-venom on peripheral nerve. This opens future scope for non-invasive clinical measurement of demyelination.
- Published
- 2016
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29. Reposing the herniated spinal nerves following accidental iatrogenic dural tear in spine surgery-The "no touch hip flexion technique".
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Tewari VK and Gupta HK
- Published
- 2014
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30. Membrane topology of human presenilin-1 in SK-N-SH cells determined by fluorescence correlation spectroscopy and fluorescent energy transfer.
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Midde K, Rich R, Saxena A, Gryczynski I, Borejdo J, and Das HK
- Subjects
- Cell Line, Tumor, Cytoplasm metabolism, Diffusion, Humans, Presenilin-1 chemistry, Protein Transport, Cell Membrane metabolism, Fluorescence Resonance Energy Transfer, Presenilin-1 metabolism
- Abstract
Presenilin-1 (PS1) protein acts as passive ER Ca(2+) leak channels that facilitate passive Ca(2+) leak across ER membrane. Mutations in the gene encoding PS1 protein cause neurodegeneration in the brains of patients with familial Alzheimer's disease (FAD). FADPS1 mutations abrogate the function of ER Ca(2+) leak channel activity in human neuroblastoma SK-N-SH cells in vitro (Das et al., J Neurochem 122(3):487-500, 2012) and in mouse embryonic fibroblasts. Consequently, genetic deletion or mutations of the PS1 gene cause calcium (Ca(2+)) signaling abnormalities leading to neurodegeneration in FAD patients. By analogy with other known ion channels it has been proposed that the functional PS1 channels in ER may be multimers of several PS1 subunits. To test this hypothesis, we conjugated the human PS1 protein with an NH2-terminal YFP-tag and a COOH-terminal CFP-tag. As expected YFP-PS1, and PS1-CFP were found to be expressed on the plasma membranes by TIRF microscopy, and both these fusion proteins increased ER Ca(2+) leak channel activity similar to PS1 (WT) in SK-N-SH cells, as determined by functional calcium imaging. PS1-CFP was either expressed alone or together with YFP-PS1 into SK-N-SH cell line and the interaction between YFP-PS1 and PS1-CFP was determined by Förster resonance energy transfer analysis. Our results suggest interaction between YFP-PS1 and PS1-CFP confirming the presence of a dimeric or multimeric form of PS1 in SK-N-SH cells. Lateral diffusion of PS1-CFP and YFP-PS1 in the plasma membrane of SK-N-SH cells was measured in the absence or in the presence of glycerol by fluorescence correlation spectroscopy to show that both COOH-terminal and NH2-terminal of human PS1 are located on the cytoplasmic side of the plasma membrane. Therefore, we conclude that both COOH-terminal and NH2-terminal of human PS1 may also be oriented on the cytosolic side of ER membrane.
- Published
- 2014
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31. Spinal anesthesia in a caesarian case after dry tap.
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Das HK, Gunjal MK, and Toshikhane HD
- Abstract
The case report here is a case of cesarean operation under subarachnoid block, which resulted after a failed lumber puncture, known to be "dry tap." The result is that it was uneventful surgery without any additive anesthetics being required after injecting 2.2 ml Bupivacaine 0.5% (H). Although cases have been reported with mixed experiences of dry tap and different causes are also explained, but still there is a need to find few other reasons for "dry tap." Hence, thought to present the case for putting forward a question that if there is any more cause for dry tap.
- Published
- 2014
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32. Retro-inferior coccygeal adventitious bursa (hadoti bursa): a study of three cases.
- Author
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Gupta HK and Patidar R
- Abstract
It is not unusual to encounter callosity at deformed bony pressure points such as at lateral malleolus of ankle or head of first metatarsal in hallux valgus. Herein, we report for the first time posterior inferior coccygeal adventitious bursa (from Hadoti area of Jhalawar in Rajasthan, India) presenting as a painless nonprogressive swelling of significant size encountered in three patients.
- Published
- 2013
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33. Bringing the visible universe into focus with Robo-AO.
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Baranec C, Riddle R, Law NM, Ramaprakash AN, Tendulkar SP, Bui K, Burse MP, Chordia P, Das HK, Davis JT, Dekany RG, Kasliwal MM, Kulkarni SR, Morton TD, Ofek EO, and Punnadi S
- Subjects
- Astronomical Phenomena, Astronomy methods, Infrared Rays, Lasers, Optics and Photonics methods, Ultraviolet Rays, Astronomy instrumentation, Optics and Photonics instrumentation, Telescopes
- Abstract
The angular resolution of ground-based optical telescopes is limited by the degrading effects of the turbulent atmosphere. In the absence of an atmosphere, the angular resolution of a typical telescope is limited only by diffraction, i.e., the wavelength of interest, λ, divided by the size of its primary mirror's aperture, D. For example, the Hubble Space Telescope (HST), with a 2.4-m primary mirror, has an angular resolution at visible wavelengths of ~0.04 arc seconds. The atmosphere is composed of air at slightly different temperatures, and therefore different indices of refraction, constantly mixing. Light waves are bent as they pass through the inhomogeneous atmosphere. When a telescope on the ground focuses these light waves, instantaneous images appear fragmented, changing as a function of time. As a result, long-exposure images acquired using ground-based telescopes--even telescopes with four times the diameter of HST--appear blurry and have an angular resolution of roughly 0.5 to 1.5 arc seconds at best. Astronomical adaptive-optics systems compensate for the effects of atmospheric turbulence. First, the shape of the incoming non-planar wave is determined using measurements of a nearby bright star by a wavefront sensor. Next, an element in the optical system, such as a deformable mirror, is commanded to correct the shape of the incoming light wave. Additional corrections are made at a rate sufficient to keep up with the dynamically changing atmosphere through which the telescope looks, ultimately producing diffraction-limited images. The fidelity of the wavefront sensor measurement is based upon how well the incoming light is spatially and temporally sampled. Finer sampling requires brighter reference objects. While the brightest stars can serve as reference objects for imaging targets from several to tens of arc seconds away in the best conditions, most interesting astronomical targets do not have sufficiently bright stars nearby. One solution is to focus a high-power laser beam in the direction of the astronomical target to create an artificial reference of known shape, also known as a 'laser guide star'. The Robo-AO laser adaptive optics system, employs a 10-W ultraviolet laser focused at a distance of 10 km to generate a laser guide star. Wavefront sensor measurements of the laser guide star drive the adaptive optics correction resulting in diffraction-limited images that have an angular resolution of ~0.1 arc seconds on a 1.5-m telescope.
- Published
- 2013
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34. Repression of transcription of presenilin-1 inhibits γ-secretase independent ER Ca²⁺ leak that is impaired by FAD mutations.
- Author
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Das HK, Tchedre K, and Mueller B
- Subjects
- Amyloid Precursor Protein Secretases genetics, Anthracenes pharmacology, Carrier Proteins metabolism, Cell Line, Tumor, Cytosol drug effects, Cytosol metabolism, DNA Helicases metabolism, Dose-Response Relationship, Drug, Endoplasmic Reticulum drug effects, Endoplasmic Reticulum genetics, Enzyme Inhibitors pharmacology, Gene Expression Regulation, Neoplastic drug effects, Gene Expression Regulation, Neoplastic genetics, Humans, Inositol 1,4,5-Trisphosphate Receptors metabolism, Methionine genetics, Mi-2 Nucleosome Remodeling and Deacetylase Complex, Neuroblastoma pathology, Neuroblastoma ultrastructure, Nuclear Proteins metabolism, Peptide Fragments genetics, Peptide Fragments metabolism, Signal Transduction drug effects, Signal Transduction genetics, Statistics, Nonparametric, Thapsigargin pharmacology, Transfection, Valine genetics, Amyloid Precursor Protein Secretases metabolism, Calcium metabolism, Endoplasmic Reticulum metabolism, Mutation genetics, Presenilin-1 genetics
- Abstract
Genetic deletion or mutations of presenilin genes (PS1/PS2) cause familial Alzheimer's disease and calcium (Ca²⁺) signaling abnormalities. PS1/PS2 act as endoplasmic reticulum (ER) Ca²⁺ leak channels that facilitate passive Ca²⁺ leak across ER membrane. Studies with PS1/PS2 double knockout (PS1/PS2-DKO) mouse embryonic fibroblasts showed that PS1/PS2 were responsible for 80% of passive Ca²⁺ leak from the lumen of endoplasmic reticulum to cytosol. Transient transfection of the wild type PS1 expression construct increased cytoplasmic Ca²⁺ as a result of Ca²⁺ leak across ER membrane whereas the FADPS1 (PS1-M146V) mutation construct alone or in combination with the wild type PS1 expression construct abrogated Ca²⁺ leak in SK-N-SH cells. Inhibition of basal c-jun-NH2-terminal kinase (JNK) activity by JNK inhibitor SP600125 repressed PS1 transcription and PS1 protein expression by augmenting p53 protein level in SK-N-SH cells (Lee and Das 2008). In this report we also showed that repression of PS1 transcription by JNK inhibitor SP600125 inhibited passive Ca²⁺ leak across ER membrane which could be rescued by expressing PS1 wild type and not by expressing FADPS1 (PS1-M146V) under a SP600125 non-responsive promoter. Treatment of SK-N-SH cells with SP600125 also triggered InsP3R-mediated Ca²⁺ release from the ER by addition of 500 nM bradykinin, an agonist of InsP3 receptor (InsP3R1) without changing the expression of InsP3R1. This data confirms that SP600125 increases the Ca²⁺ store in the ER by inhibiting PS1-mediated Ca²⁺ leak across ER membrane. p53, ZNF237 and Chromodomain helicase DNA-binding protein 3 which are repressors of PS1 transcription, also reduced Ca²⁺ leak across ER membrane in SK-N-SH cells but γ-secretase inhibitor or dominant negative γ-secretase-specific PS1 mutant (PS1-D257A) had no significant effect. Therefore, p53, ZNF237, and Chromodomain helicase DNA-binding protein 3 inhibit the function ER Ca²⁺ leak channels to regulate both ER and cytoplasmic Ca²⁺ levels and may potentially control Ca²⁺-signaling function of PS1., (© 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.)
- Published
- 2012
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35. Intraperitoneal injection of JNK-specific inhibitor SP600125 inhibits the expression of presenilin-1 and Notch signaling in mouse brain without induction of apoptosis.
- Author
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Rahman M, Zhang Z, Mody AA, Su DM, and Das HK
- Subjects
- Amyloid Precursor Protein Secretases biosynthesis, Amyloid Precursor Protein Secretases genetics, Amyloid beta-Protein Precursor biosynthesis, Amyloid beta-Protein Precursor genetics, Animals, Anthracenes administration & dosage, Blotting, Western, Enzyme Inhibitors administration & dosage, Fluorescent Antibody Technique, Genes, p53 drug effects, Genes, p53 genetics, In Situ Nick-End Labeling, Injections, Intraperitoneal, Male, Mice, Mice, Inbred C57BL, Phosphorylation, RNA, Messenger biosynthesis, RNA, Messenger genetics, Real-Time Polymerase Chain Reaction, Anthracenes pharmacology, Apoptosis drug effects, Brain cytology, Brain Chemistry drug effects, Enzyme Inhibitors pharmacology, JNK Mitogen-Activated Protein Kinases antagonists & inhibitors, Presenilin-1 biosynthesis, Receptor, Notch1 drug effects, Signal Transduction drug effects
- Abstract
Presenilin-1 (PS1) is a multifunctional protein involved in many cellular functions including the processing of type 1 membrane proteins such as β-amyloid precursor protein (APP) and Notch 1 receptor. PS1 acts as the catalytic subunit of the γ-secretase complex, and participates in Notch 1 processing to release Notch intracellular domain (NICD) in the cytoplasm. NICD subsequently migrates to the nucleus and causes Notch signaling by increasing the expression of the Hes1 gene. We have previously shown that inhibition of basal activity of c-jun-NH2-terminal kinase (JNK) with JNK-specific inhibitor SP600125 represses the expression of PS1 and γ-secretase activity by increasing p53 level in SK-N-SH cell line in vitro (Lee and Das, 2008, 2010). However, it is largely unknown whether PS1 can be effectively suppressed in vivo in adult mouse brains. In this report we showed that intraperitoneal (i.p) injection of JNK-specific inhibitor SP600125 decreased p-JNK level, and reduced PS1 expression by increasing p53 level in adult mouse brains. We also showed that suppression of PS1 expression by SP600125 reduced γ-secretase activity which decreased Notch 1 processing to reduce NICD in mouse brains. Furthermore, inhibition of Notch 1 processing by SP600125 decreased Notch 1 signaling by reducing the expression of the NICD target Hes1 gene in mouse brains without induction of apoptosis. These results provide insights for further study on PS1-mediated reduction of Notch 1 and APP processing for the treatment of Alzheimer's disease., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2012
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36. Evidence for pre- and post-power stroke of cross-bridges of contracting skeletal myofibrils.
- Author
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Midde K, Luchowski R, Das HK, Fedorick J, Dumka V, Gryczynski I, Gryczynski Z, and Borejdo J
- Subjects
- Animals, Anisotropy, Fluorescence Polarization, Imaging, Three-Dimensional, Muscle Contraction drug effects, Muscle Relaxation drug effects, Muscle Relaxation physiology, Muscle, Skeletal drug effects, Myofibrils drug effects, Myosin Light Chains metabolism, Normal Distribution, Rabbits, Rhodamines pharmacology, Sarcomeres physiology, Time Factors, Muscle Contraction physiology, Muscle, Skeletal physiology, Myofibrils physiology
- Abstract
We examined the orientational fluctuations of a small number of myosin molecules (approximately three) in working skeletal muscle myofibrils. Myosin light chain 1 (LC1) was labeled with a fluorescent dye and exchanged with the native LC1 of skeletal muscle myofibrils cross-linked with 1-ethyl-3-[3(dimethylamino) propyl] carbodiimide to prevent shortening. We observed a small volume within the A-band (∼10(-15) L) by confocal microscopy, and measured cyclic fluctuations in the orientation of the myosin neck (containing LC1) by recording the parallel and perpendicular components of fluorescent light emitted by the fluorescently labeled myosin LC1. Histograms of orientational fluctuations from fluorescent molecules in rigor were represented by a single Gaussian distribution. In contrast, histograms from contracting muscles were best fit by at least two Gaussians. These results provide direct evidence that cross-bridges in working skeletal muscle assume two distinct conformations, presumably corresponding to the pre- and post-power-stroke states., (Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2011
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37. Transcriptional regulation of the presenilin-1 gene controls gamma-secretase activity.
- Author
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Lee S and Das HK
- Subjects
- Amyloid beta-Peptides metabolism, Analysis of Variance, Anthracenes pharmacology, Benzothiazoles pharmacology, Blotting, Western, Cell Line, Tumor, Chromatin Immunoprecipitation, DNA Primers genetics, Enzyme-Linked Immunosorbent Assay, Gene Expression Regulation physiology, Genetic Vectors genetics, Humans, JNK Mitogen-Activated Protein Kinases antagonists & inhibitors, Peptide Fragments metabolism, Reverse Transcriptase Polymerase Chain Reaction, Toluene analogs & derivatives, Toluene pharmacology, Amyloid Precursor Protein Secretases metabolism, Amyloid beta-Protein Precursor metabolism, Gene Expression Regulation drug effects, Presenilin-1 metabolism
- Abstract
Inhibition of basal JNK activity by JNK inhibitor SP600125 or JNK1siRNA repressed presenilin-1 (PS1) expression in SK-N-SH cells by augmenting the level of p53, a repressor of the PS1 gene (1). We now showed that repression of PS1 transcription by JNK inhibitor SP600125 inhibited gamma-secretase mediated processing of amyloid precursor protein (APP) resulting in the accumulation of C99 fragment and the reduction of secreted Abeta40 level without altering the expression of nicastrin (NCT). Co-treatment of cells with SP600125 and p53 inhibitor, pifithrin-alpha, partially nullified the suppressive effects of SP610025 on PS1 expression and secreted Abeta40 level. Suppression of JNK1 by JNK1siRNA also decreased Abeta40 level. Furthermore, overexpression of the repressors p53, ZNF237 and CHD3 of the PS1 gene also suppressed the processing of APP through repression of PS1 transcription by deacetylation of histone at the PS1 promoter. Transcriptional activator Ets2 increased PS1 protein and secreted Abeta40 levels without affecting the expression of NCT by activating PS1 transcription via hyper-acetylation of histone at the PS1 promoter. Therefore, regulation of PS1 transcription modulates gamma-secretase activity.
- Published
- 2010
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38. The risk of HIV and HCV infections among injection drug users in northeast India.
- Author
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Mahanta J, Borkakoty B, Das HK, and Chelleng PK
- Subjects
- Adolescent, Adult, Cross-Sectional Studies, Female, Humans, India epidemiology, Male, Prevalence, Young Adult, HIV Infections epidemiology, Hepatitis C, Chronic epidemiology, Substance Abuse, Intravenous epidemiology
- Abstract
Injection drug users (IDUs) and their associated risk behavior are responsible for driving the human immunodeficiency virus (HIV) epidemic in northeast India. So a group of IDUs from two northeastern states (Mizoram and Nagaland) of India were studied to find the prevalence of HIV, co-infection with hepatitis C virus (HCV), hepatitis B virus (HBV), and associated risk behaviors. Out of the 400 IDUs enrolled, 398 consented for HIV, HCV, and hepatitis B surface antigen (HbsAg) test. Of them, 10.8% were HIV-1 antibody positive, 47.8% had HCV antibody, and 3.8% had detectable HBsAg. Among the HIV infected subjects, 79.1% were co-infected with HCV and 6.9% had triple infection. Heroin users showed a higher association with HIV (OR = 7.3, 95% CI: 2.5-21.5, p=0.0003) and HCV infection (OR = 7.6, 95% CI: 3.5-16.6, p<0.0001) than Spasmo-proxyvon (dextropropoxyphene, a synthetic opiod analgesic). In summary, apart from the known risk variables among IDUs, type of injecting drugs also influences the HIV/HCV transmission pattern among the IDUs.
- Published
- 2009
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39. Overexpression of human histone methylase MLL1 upon exposure to a food contaminant mycotoxin, deoxynivalenol.
- Author
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Ansari KI, Hussain I, Das HK, and Mandal SS
- Subjects
- Binding Sites genetics, Blotting, Western, Cell Line, Tumor, Chromatin Immunoprecipitation, Dose-Response Relationship, Drug, Histone-Lysine N-Methyltransferase, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Humans, Myeloid-Lymphoid Leukemia Protein metabolism, Oligonucleotides, Antisense genetics, Promoter Regions, Genetic genetics, Protein Binding drug effects, Pyrimidines pharmacology, Reverse Transcriptase Polymerase Chain Reaction, Sp2 Transcription Factor genetics, Sp2 Transcription Factor metabolism, Transfection, src-Family Kinases antagonists & inhibitors, src-Family Kinases metabolism, Gene Expression Regulation, Neoplastic drug effects, Myeloid-Lymphoid Leukemia Protein genetics, Trichothecenes pharmacology
- Abstract
Mixed lineage leukemias (MLLs) are histone-methylating enzymes with critical roles in gene expression, epigenetics and cancer. Although MLLs are important gene regulators little is known about their own regulation. Herein, to understand the effects of toxic stress on MLL gene regulation, we treated human cells with a common food contaminant mycotoxin, deoxynivalenol (DON). Our results demonstrate that MLLs and Hox genes are overexpressed upon exposure to DON. Studies using specific inhibitors demonstrated that Src kinase families are involved in upstream events in DON-mediated upregulation of MLL1. Sequence analysis demonstrated that the MLL1 promoter contains multiple Sp1-binding sites and importantly, the binding of Sp1 is enriched in the MLL1 promoter upon exposure to DON. Moreover, antisense-mediated knockdown of Sp1 diminished DON-induced MLL1 upregulation. These results demonstrated that MLL1 gene expression is sensitive to toxic stress and Sp1 plays crucial roles in the stress-induced upregulation of MLL1.
- Published
- 2009
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40. Injecting and sexual risk behaviours, sexually transmitted infections and HIV prevalence in injecting drug users in three states in India.
- Author
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Mahanta J, Medhi GK, Paranjape RS, Roy N, Kohli A, Akoijam BS, Dzuvichu B, Das HK, Goswami P, and Thongamba G
- Subjects
- Adolescent, Adult, Age Distribution, Age Factors, Blood-Borne Pathogens, Condoms statistics & numerical data, HIV Infections epidemiology, HIV Infections prevention & control, Health Knowledge, Attitudes, Practice, Humans, India epidemiology, Male, Sexually Transmitted Diseases epidemiology, Sexually Transmitted Diseases prevention & control, Sexually Transmitted Diseases transmission, Substance Abuse, Intravenous epidemiology, Young Adult, HIV Infections transmission, Risk-Taking, Sexual Behavior statistics & numerical data, Substance Abuse, Intravenous complications
- Abstract
Objective: To describe and compare sexual and injecting risk behaviours and sexually transmitted infections (STI), hepatitis C virus (HCV) and HIV prevalence in injecting drug users (IDU) in six districts in three states of India: Manipur, Nagaland, and Maharashtra., Method: The respondent-driven sample consisted of 2075 IDU. Consenting participants were administered a structured questionnaire and samples of blood and urine were collected to test for HIV and STI. Data were analysed using RDSAT., Results: In two districts in Manipur, 77 and 98% of IDU injected heroin, whereas the main injecting drug in Nagaland was dextropropoxyphene (99%). In Mumbai/Thane, Maharashtra, the majority of respondents reported using chlorpheniramine (87%) and heroin (99%). In all districts, almost half of IDU reported generally sharing needles and syringes; consistent condom use with non-paid female partners was also low. Approximately one-quarter of IDU in Mumbai/Thane visited a paid partner in the past year. IDU with reactive syphilis serology were higher in Nagaland (7 and 19%) than in Manipur and Maharashtra. HIV in two districts of Manipur (23%, 32%) and Mumbai/Thane (16%) was greater than Nagaland (<2%). HCV prevalence was more than 50% in Mumbai/Thane and Manipur., Conclusion: Irrespective of regional differences, high-risk behaviour of needle sharing and low condom use makes IDU a critical subpopulation for HIV prevention interventions. Interventions need to address the differing drug use patterns in the regions and transmission prevention among non-paid regular and casual female partners of IDU in the northeast districts and paid female partners in Mumbai/Thane.
- Published
- 2008
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41. Risk of hepatitis C infection among injection drug users in Mizoram, India.
- Author
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Chelleng PK, Borkakoty BJ, Chetia M, Das HK, and Mahanta J
- Subjects
- Adolescent, Adult, Female, Hepatitis C Antibodies blood, Humans, Logistic Models, Male, Middle Aged, Risk Factors, Hepatitis C etiology, Substance Abuse, Intravenous complications
- Abstract
Background & Objective: Prevalence of injection drug users (IDUs) is high in the northeastern region of India. This coupled with unsafe injecting practices as well as practice of tattooing in remote tribal areas call for baseline data on the prevalence of parentally transmitted viral diseases. In the present study we aimed to measure the risk behaviours and seroprevalence of hepatitis C virus (HCV) antibodies amongst IDUs of Mizoram, a State of the northeast India., Methods: A cross-sectional study was conducted in 2004-2005 amongst IDUs (including female sex workers) who had injected in the past six months and were unaware of their HCV/HIV status. They were recruited from various drop-in centers from Aizawl, Mizoram, and screened for anti-HCV antibodies using 3(rd) generation HCV EIA and recombinant immunoblot assay (RIBA)., Results: The prevalence of HCV antibodies was 71.2 per cent among the active IDUs. On univariate analysis increasing duration of injection, syringe sharing and heroin (diacetylmorphine) injectors were at a significantly higher risk of acquiring HCV antibodies (P<0.001). On multivariate analysis, HCV antibody prevalence showed a strong association with the type of drugs injected (P=0.001), frequency of injecting (P=0.013), multiplicity of drugs abused (P=0.004), and needle syringe sharing (P=0.003)., Interpretation & Conclusion: Unsafe injecting practices were found to be associated with a higher risk of acquiring hepatitis C infection. Our findings showed that syringe and needle exchange programme alone was not sufficient as a preventive strategy for control of hepatitis C infection among IDUs of Aizawl.
- Published
- 2008
42. Inhibition of basal activity of c-jun-NH2-terminal kinase (JNK) represses the expression of presenilin-1 by a p53-dependent mechanism.
- Author
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Lee S and Das HK
- Subjects
- Analysis of Variance, Anthracenes pharmacology, Cell Line, Tumor, Chromatin Immunoprecipitation methods, Dose-Response Relationship, Drug, Enzyme Inhibitors pharmacology, Gene Expression drug effects, Humans, Mitogen-Activated Protein Kinase 8 metabolism, Neuroblastoma, Presenilin-1 genetics, RNA, Small Interfering pharmacology, Transcription, Genetic, Up-Regulation drug effects, Gene Expression physiology, JNK Mitogen-Activated Protein Kinases metabolism, Presenilin-1 metabolism, Tumor Suppressor Protein p53 physiology, Up-Regulation physiology
- Abstract
Presenilin-1 (PS1) is a multifunctional protein involved in many cellular functions including the processing of type 1 transmembrane proteins and regulation of calcium signaling. Although PS1 is important in many aspects of cellular functions, little is known about the PS1 gene regulation in the context of intracellular signal pathways. We tested the role of c-jun-NH2-terminal kinase (JNK) on PS1 gene expression using a JNK specific inhibitor, SP600125. SP600125 efficiently suppressed basal JNK activity in SK-N-SH cell line as shown by inhibition of phosphor-JNK and phosphor-c-jun, and also decreased PS1 expression. Previously we reported that Ets1/2 bind to the PS1 promoter to activate PS1 transcription and p53 represses PS1 transcription without direct binding to the PS1 promoter [Pastorcic, M., Das, H.K., 2000. Regulation of transcription of the human presenilin-1 gene by ets transcription factors and the p53 protooncogene. J Biol Chem. 275, 34938-45.]. Involvement of protein-protein interaction between p53 and other transcription factors was speculated to be a mechanism by which p53 represses PS1 expression. Therefore, we tested whether the interaction between p53 and Ets1/2 is involved in JNK-mediated inhibition of PS1 expression. In this report we showed that p53 level was upregulated by SP600125 in SK-N-SH cell line. In addition, protein-protein interaction between p53 and Ets1/2 was enhanced with a concomitant dissociation of Ets1/2 from the PS1 promoter resulting in the suppression of PS1 transcription. We also showed that suppression of JNK1 by JNK1 siRNA increased p53 protein level and decreased PS1 expression. This observation was supported by the fact that overexpression of p53 in SK-N-SH cell line promoted dissociation of Ets1/2 from the PS1 promoter and suppressed PS1 expression. Furthermore, p53 inhibitor pifithrin-alpha partially nullified the suppressive effects of SP600125 on PS1 expression. We also showed that transfection of p53 was required for SP600125-mediated suppression of PS1 expression in p53-deficient PC3 cell line suggesting that inhibition of basal JNK activity suppresses PS1 expression through a p53-dependent mechanism.
- Published
- 2008
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- View/download PDF
43. ADR1 interacts with a down-stream positive element to activate PS1 transcription.
- Author
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Das HK and Baez ML
- Subjects
- Brain Neoplasms, Cationic Amino Acid Transporter 1 genetics, Cell Line, Tumor, DNA Primers, DNA-Binding Proteins metabolism, Humans, Neuroblastoma, Polymerase Chain Reaction, Promoter Regions, Genetic, Saccharomyces cerevisiae Proteins metabolism, Transcription Factors metabolism, Transcription, Genetic, Alzheimer Disease genetics, Amyloid Precursor Protein Secretases genetics, Gene Expression Regulation, Presenilin-1 genetics
- Abstract
We have identified downstream promoter sequence of the PS1 gene that may be regulated by novel transcription factors. 3' deletion from +178 to +165 had no effect on PS1 transcription. 3' deletion from +178 to +140 decreased promoter activity by 50%. Further 3' deletion from +178 to +114 decreased promoter activity by 80%. Therefore, a crucial element controlling over 80% of the promoter activity in SK-N-SH cell line is located between +114 and +165. Electrophoretic mobility shift assays suggested that zinc finger proteins Sp1 and ADR1 interacted with the PS1 promoter sequence (+114 to +140) and promoter region (+140 to +165) respectively. A three base pair substitution within the core sequence (GGCGGGGA to GGCGactA) of the ADR1 consensus in the element (+140 to +165) that abolished ADR1-DNA interaction, reduced PS1 transcription by 50%. The substitution mutation in the sequence (+114 to +140) that abolished Sp1-DNA interaction had no effect on PS1 expression. These data suggest that a novel mammalian trans-activator protein ADR1 binds to the downstream element (+140 to +165) to activate PS1 transcription.
- Published
- 2008
- Full Text
- View/download PDF
44. Transcriptional regulation of the presenilin-1 gene: implication in Alzheimer's disease.
- Author
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Das HK
- Subjects
- Alzheimer Disease genetics, Apoptosis, Dementia genetics, Humans, Models, Biological, Mutation, Neurodegenerative Diseases genetics, Neurodegenerative Diseases metabolism, Neurons metabolism, Protein Binding, Transcription Factors metabolism, Alzheimer Disease metabolism, Gene Expression Regulation, Presenilin-1 biosynthesis, Presenilin-1 genetics, Transcription, Genetic
- Abstract
Two (amyloid and presenilin) hypotheses have been proposed to explain the pathogenesis of Alzheimer's disease (AD). According to amyloid hypothesis, the main amyloid plaques which are hallmark of AD are generated by beta- and gamma-secretase mediated proteolytic processing of amyloid precursor protein (APP). The amyloid hypothesis does not adequately address the pathogenesis of the disease, however, since transgenic mice that express the pathologic mutations of the APP and presenilin-1 (PS1) genes produce amyloid plaques but fail to exhibit neurodegeneration and memory loss observed in AD patients. According to presenilin hypothesis, loss of essential functions of PS due to decreased PS expression or mutations in the PS genes better explains the pathogenesis of AD. Recent studies have revealed that forebrain specific conditional knockouts of PS1 and PS2 genes (cPSKO) cause both neuronal degeneration and memory loss without evidence of formation of amyloid plaques. Another potential mechanism for the pathogenesis of AD may reside at the transcriptional regulation of the presenilin-1 gene. In this review, a detailed analysis of transcription factors that regulate PS1 transcription will be discussed. An in depth understanding of the regulatory mechanism of PS1 transcription can identify the targets that can potentially be used in therapeutic intervention of AD.
- Published
- 2008
- Full Text
- View/download PDF
45. Hepatitis C virus infection and risk behaviors among injection drug users of Nagaland.
- Author
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Das HK, Borkakoty BJ, Mahanta J, Medhi GK, and Chelleng PK
- Subjects
- Adolescent, Adult, Enzyme-Linked Immunosorbent Assay, Female, Hepatitis C blood, Hepatitis C immunology, Hepatitis C Antibodies blood, Humans, India epidemiology, Male, Risk-Taking, Hepatitis C epidemiology, Substance Abuse, Intravenous
- Published
- 2007
46. The C-terminal region of CHD3/ZFH interacts with the CIDD region of the Ets transcription factor ERM and represses transcription of the human presenilin 1 gene.
- Author
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Pastorcic M and Das HK
- Subjects
- Adenosine Triphosphatases chemistry, Amino Acid Sequence, Base Sequence, Binding Sites, Cell Line, DNA Helicases chemistry, DNA Primers, DNA-Binding Proteins chemistry, Humans, Mi-2 Nucleosome Remodeling and Deacetylase Complex, Molecular Sequence Data, Repressor Proteins chemistry, Transcription Factors chemistry, Two-Hybrid System Techniques, Adenosine Triphosphatases metabolism, DNA Helicases metabolism, DNA-Binding Proteins metabolism, Presenilin-1 genetics, Repressor Proteins metabolism, Transcription Factors metabolism, Transcription, Genetic
- Abstract
Presenilins are required for the function of gamma-secretase: a multiprotein complex implicated in the development of Alzheimer's disease (AD). We analyzed expression of the presenilin 1 (PS1) gene. We show that ERM recognizes avian erythroblastosis virus E26 oncogene homolog (Ets) motifs on the PS1 promoter located at -10, +90, +129 and +165, and activates PS1 transcription with promoter fragments containing or not the -10 Ets site. Using yeast two-hybrid selection we identified interactions between the chromatin remodeling factor CHD3/ZFH and the C-terminal 415 amino acids of ERM used as bait. Clones contained the C-terminal region of CHD3 starting from amino acid 1676. This C-terminal fragment (amino acids 1676-2000) repressed transcription of the PS1 gene in transfection assays and PS1 protein expression from the endogenous gene in SH-SY5Y cells. In cells transfected with both CHD3 and ERM, activation of PS1 transcription by ERM was eliminated with increasing levels of CHD3. Progressive N-terminal deletions of CHD3 fragment (amino acids 1676-2000) indicated that sequences crucial for repression of PS1 and interactions with ERM in yeast two-hybrid assays are located between amino acids 1862 and 1877. This was correlated by the effect of progressive C-terminal deletions of CHD3, which indicated that sequences required for repression of PS1 lie between amino acids 1955 and 1877. Similarly, deletion to amino acid 1889 eliminated binding in yeast two-hybrid assays. Testing various shorter fragments of ERM as bait indicated that the region essential for binding CHD3/ZFH is within the amino acid region 96-349, which contains the central inhibitory DNA-binding domain (CIDD) of ERM. N-Terminal deletions of ERM showed that residues between amino acids 200 and 343 are required for binding to CHD3 (1676-2000) and C-terminal deletions of ERM indicated that amino acids 279-299 are also required. Furthermore, data from chromatin immunoprecipitation (ChIP) indicate that CHD3/ZFH interacts with the PS1 promoter in vivo.
- Published
- 2007
- Full Text
- View/download PDF
47. Analysis of transcriptional modulation of the presenilin 1 gene promoter by ZNF237, a candidate binding partner of the Ets transcription factor ERM.
- Author
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Pastorcic M and Das HK
- Subjects
- Carrier Proteins pharmacology, Cell Line, Tumor, Cloning, Molecular, DNA-Binding Proteins pharmacology, Dose-Response Relationship, Drug, Drug Interactions, Electrophoretic Mobility Shift Assay methods, Gene Expression Regulation, Neoplastic drug effects, Humans, Mutagenesis physiology, Neuroblastoma, Nuclear Proteins, Protein Structure, Tertiary physiology, Sequence Analysis, Protein methods, Transcription Factors pharmacology, Transcriptional Activation drug effects, Transfection methods, Two-Hybrid System Techniques, Carrier Proteins physiology, DNA-Binding Proteins physiology, Gene Expression Regulation, Neoplastic physiology, Presenilin-1 genetics, Promoter Regions, Genetic physiology, Transcription Factors physiology
- Abstract
DNA sequences required for the expression of the human presenilin 1 (PS1) gene have been identified between -118 and +178 flanking the major initiation site (+1) mapped in SK-N-SH cells. Several Ets sites are located both upstream as well as downstream from the +1 site, including an Ets motif present at -10 that controls 90% of transcription in SK-N-SH cells. However, in SH-SY5Y cells, transcription initiates further downstream and requires an alternative set of promoter elements including a +90 Ets motif. Ets2, ER81, ERM and Elk1 were identified by yeast one-hybrid selection in a human brain cDNA library using the -10 Ets motif as a bait. We have shown that ERM recognizes specifically Ets motifs on the PS1 promoter located at -10 as well as downstream at +90, +129 and +165 and activates PS1 transcription with promoter fragments whether or not they contain the -10 Ets site. We have now searched for ERM interacting proteins by yeast two-hybrid selection in a human brain cDNA library using the C-terminal 415 amino acid of ERM as a bait. One of the interacting proteins was ZNF237, a member of the MYM gene family. It is widely expressed in different tissues in eukaryotes under several forms derived by alternative splicing, including a large 382 amino acid form containing a single MYM domain, and 2 shorter forms of 208 and 213 amino acids respectively that do not. We show that both the 382 as well as the 208 amino acid forms are expressed in SK-N-SH cells but not in SH-SY5Y cells. Both forms interact with ERM and repress the transcription of PS1 in SH-SY5Y cells. The effect of both C-terminal and N-terminal deletions indicates that the N-terminal 120 amino acid region is required for interaction with ERM in yeast, and furthermore single amino acid mutations show that residues 112 and 114 play an important role. The repression of transcription in SH-SY5Y cells also appears to require the N-terminal potion of ZNF237 and was affected by mutation of the amino acid 112. Data from electrophoretic mobility shift assays indicate that ERM and possibly ZNF237 interact with a fragment of the PS1 promoter.
- Published
- 2007
- Full Text
- View/download PDF
48. Identification of a positive transcription regulatory element within the coding region of the nifLA operon in Azotobacter vinelandii.
- Author
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Mitra R, Das HK, and Dixit A
- Subjects
- Azotobacter vinelandii metabolism, Bacterial Proteins metabolism, Base Sequence, Binding Sites, DNA Footprinting, Gene Deletion, Molecular Sequence Data, Promoter Regions, Genetic, Transcription Factors metabolism, Transcription, Genetic, Azotobacter vinelandii genetics, Bacterial Proteins genetics, Enhancer Elements, Genetic, Gene Expression Regulation, Bacterial, Operon, Transcription Factors genetics
- Abstract
Nitrogen fixation in Azotobacter vinelandii is regulated by the nifLA operon. NifA activates the transcription of nif genes, while NifL antagonizes the transcriptional activator NifA in response to fixed nitrogen and molecular oxygen levels. However, transcriptional regulation of the nifLA operon of A. vinelandii itself is not fully understood. Using the S1 nuclease assay, we mapped the transcription start site of the nifLA operon, showing it to be similar to the sigma54-dependent promoters. We also identified a positive cis-acting regulatory element (+134 to +790) of the nifLA operon within the coding region of the nifL gene of A. vinelandii. Deletion of this element results in complete loss of promoter activity. Several protein factors bind to this region, and the specific binding sites have been mapped by DNase I foot printing. Two of these sites, namely dR1 (+134 to +204) and dR2 (+745 to +765), are involved in regulating the nifLA promoter activity. The absence of NtrC-like binding sites in the upstream region of the nifLA operon in A. vinelandii makes the identification of these downstream elements a highly significant finding. The interaction of the promoter with the proteins binding to the dR2 region spanning +745 to +765 appears to be dependent on the face of the helix as introduction of 4 bases just before this region completely disrupts promoter activity. Thus, the positive regulatory element present within the BglII-BglII fragment may play, in part; an important role in nifLA regulation in A. vinelandii.
- Published
- 2005
- Full Text
- View/download PDF
49. Alternative initiation of transcription of the human presenilin 1 gene in SH-SY5Y and SK-N-SH cells. The role of Ets factors in the regulation of presenilin 1.
- Author
-
Pastorcic M and Das HK
- Subjects
- Amino Acid Motifs, Base Sequence, Cell Line, Tumor, DNA-Binding Proteins chemistry, DNA-Binding Proteins metabolism, Drosophila Proteins chemistry, Drosophila Proteins metabolism, Gene Deletion, Humans, Molecular Sequence Data, Mutagenesis, Site-Directed, Presenilin-1, Promoter Regions, Genetic genetics, Proto-Oncogene Proteins chemistry, Proto-Oncogene Proteins genetics, Proto-Oncogene Proteins metabolism, Proto-Oncogene Proteins pharmacology, Proto-Oncogene Proteins c-ets, Recombinant Proteins genetics, Recombinant Proteins metabolism, Transcription Factors chemistry, Transcription Factors genetics, Transcription Factors metabolism, Transcription Factors pharmacology, Transcription Initiation Site, Transcription, Genetic, ets-Domain Protein Elk-1, Membrane Proteins biosynthesis, Membrane Proteins genetics, Proto-Oncogene Proteins physiology, Transcription Factors physiology
- Abstract
We have identified DNA sequences required for the expression of the presenilin 1 (PS1) gene. A promoter region has been mapped in SK-N-SH cells and includes sequences between -118 and +178 flanking the major initiation site (+1). The PS1 gene is also efficiently transcribed in the SH-SY5Y subclone of SK-N-SH cells. However the promoter appears to be utilized in alternative ways in both cell types. Sequences both upstream as well as downstream from the initiation site mapped in SK-N-SH cells were shown by 5'- and 3'-deletion analysis to play a crucial role in both cell lines. However, in SH-SY5Y cells either upstream or downstream sequences are sufficient to direct transcription, whereas in SK-N-SH cells 5'-deletions past the +1 site eliminate over 95% of transcription. Several Ets motifs (GGAA) as well as Sp1 motifs [(G/T)GGCGGRRY] are juxtaposed both upstream and downstream from +1. To understand how the promoter may be utilized alternatively in different cell types we have examined the effect of point mutations in these elements. Altering an Ets motif at -10 eliminates 80% of transcription in SK-N-SH cells whereas the same mutation has only a minor effect in SH-SY5Y cells. Conversely, mutation of the Ets element at +90, which eliminates 70% of transcription in SH-SY5Y cells, has a lesser effect in SK-N-SH cells. In both cell types a promoter including mutations at both -10 and +90 sites loses over 90% transcription activity indicating the crucial importance of these two Ets motifs. The effect of Sp1 mutations appears to be similar in both cell types. Hence the differential expression in each cell type may be at least partially determined by Ets factors and the -10/+90 sites. We have identified several Ets factors that recognize specifically the -10 Ets motif by the yeast one-hybrid selection including avian erythroblastosis virus E26 oncogene homologue 2, Ets-like gene 1, Ets translocation variant 1 and Ets related molecule (ERM). We show here that ERM specifically recognizes Ets motifs on the PS1 promoter located at -10 as well as downstream at +90, +129 and +165 and activates PS1 transcription with promoter fragments containing or not the -10 Ets site.
- Published
- 2004
- Full Text
- View/download PDF
50. Arsenic concentrations in rice, vegetables, and fish in Bangladesh: a preliminary study.
- Author
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Das HK, Mitra AK, Sengupta PK, Hossain A, Islam F, and Rabbani GH
- Subjects
- Agriculture, Animals, Bangladesh, Environmental Monitoring, Humans, Public Health, Safety, Arsenic analysis, Fishes, Food Contamination, Oryza chemistry, Soil Pollutants analysis, Vegetables chemistry, Water Pollutants analysis
- Abstract
Arsenic contaminating groundwater in Bangladesh is one of the largest environmental health hazards in the world. Because of the potential risk to human health through consumption of agricultural produce grown in fields irrigated with arsenic contaminated water, we have determined the level of contamination in 100 samples of crop, vegetables and fresh water fish collected from three different regions in Bangladesh. Arsenic concentrations were determined by hydride generation atomic absorption spectrophotometry. All 11 samples of water and 18 samples of soil exceeded the expected limits of arsenic. No samples of rice grain (Oryza sativa L.) had arsenic concentrations more than the recommended limit of 1.0 mg/kg. However, rice plants, especially the roots had a significantly higher concentration of arsenic (2.4 mg/kg) compared to stem (0.73 mg/kg) and rice grains (0.14 mg/kg). Arsenic contents of vegetables varied; those exceeding the food safety limits included Kachu sak (Colocasia antiquorum) (0.09-3.99 mg/kg, n=9), potatoes (Solanum tuberisum) (0.07-1.36 mg/kg, n=5), and Kalmi sak (Ipomoea reptoms) (0.1-1.53 mg/kg, n=6). Lata fish (Ophicephalus punctatus) did not contain unacceptable levels of arsenic. These results indicate that arsenic contaminates some food items in Bangladesh. Further studies with larger samples are needed to demonstrate the extent of arsenic contamination of food in Bangladesh.
- Published
- 2004
- Full Text
- View/download PDF
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