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Biomedical subjects

N Begum

Publications and source records attributed to N Begum.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of sputum smear-positive tuberculosis in a rural area in Bangladesh.

The objective of the study was to determine the prevalence of smear-positive tuberculosis (TB) in a rural area in Bangladesh at Matlab. A TB surveillance system was established among 106,000 people in rural Bangladesh at Matlab. Trained field workers interviewed all persons aged > or = 15 years to detect suspected cases of TB (cough > 21 days) and sputum specimens of suspected cases were examined for acid-fast bacilli (AFB). Of 59,395 persons interviewed, 4235 (7.1%) had a cough for > 21 days. Sputum specimens were examined for AFB from 3834 persons, 52 (1.4%) of them were positive for AFB. The prevalence of chronic cough and sputum positivity were significantly higher among males compared to females (P < 0.001). The population-based prevalence rate of smear-positive TB cases was 95/100,000 among persons aged > or = 15 years. Cases of TB clustered geographically (relative risk 5.53, 95% CI 3.19-9.59). The high burden of TB among rural population warrants appropriate measures to control TB in Bangladesh. The higher prevalence of persistent cough and AFB-positive sputum among males need further exploration. Factors responsible for higher prevalence of TB in clusters should be investigated.

Adolescent↗
PubMed2005

Quality of care for under-fives in first-level health facilities in one district of Bangladesh.

OBJECTIVE: The multi-country evaluation of Integrated Management of Childhood Illness (IMCI) effectiveness, cost and impact (MCE) is a global evaluation to determine the impact of IMCI on health outcomes and its cost-effectiveness. MCE studies are under way in Bangladesh, Brazil, Peru, Uganda and the United Republic of Tanzania. The objective of this analysis from the Bangladesh MCE study was to describe the quality of care delivered to sick children under 5 years old in first-level government health facilities, to inform government planning of child health programmes. METHODS: Generic MCE Health Facility Survey tools were adapted, translated and pre-tested. Medical doctors trained in IMCI and these tools conducted the survey in all 19 health facilities in the study areas. The data were collected using observations, exit interviews, inventories and interviews with facility providers. FINDINGS: Few of the sick children seeking care at these facilities were fully assessed or correctly treated, and almost none of their caregivers were advised on how to continue the care of the child at home. Over one-third of the sick children whose care was observed were managed by lower-level workers who were significantly more likely than higher-level workers to classify the sick child correctly and to provide correct information on home care to the caregiver. CONCLUSION: These results demonstrate an urgent need for interventions to improve the quality of care provided for sick children in first-level facilities in Bangladesh, and suggest that including lower-level workers as targets for IMCI case-management training may be beneficial. The findings suggest that the IMCI strategy offers a promising set of interventions to address the child health service problems in Bangladesh.

Bangladesh↗
PubMed2004

Epitope analysis of the cerebrospinal fluid IgG in HTLV-I associated myelopathy patients using phage display method.

We, for the first time, analyzed the binding motifs of immunoglobulin G (IgG) in the cerebrospinal fluid (CSF) of human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients with a phage library displaying 12-mer random peptides. As a result, the sequences highly homologous to HTLV-I gp46 192-199, 237-243 and 255-261 were the common linear epitopes of high affinity- IgG exclusively detected in both CSF and sera of the patients. These IgG responses were confirmed with corresponding HTLV-I peptides and serum antibody titers significantly correlated with disease severity or duration. Gp46 237-243 has not been detected in previous enzyme-linked immunosorbent assay (ELISA) studies using bound longer peptides, suggesting the usefulness of the phage display method.

Adult↗
PubMed2002

Analgesic activity of Enhydra fluctuans.

The methanol extract of Enhydra fluctuans, given orally at the dose of 250 and 500 mg/kg, was evaluated for its analgesic activity using the acetic acid induced writhing and the tail-flick methods. The extract showed promising activity in both tests.

Aminopyrine↗
PubMed2001

Sexually transmitted infections among married women in Dhaka, Bangladesh: unexpected high prevalence of herpes simplex type 2 infection.

OBJECTIVES: To document the prevalence of reproductive tract infections (RTI) and sexually transmitted infections (STI) among women attending a basic healthcare clinic in Dhaka, Bangladesh, to identify risk factors associated with the diseases and to estimate the incidence of syphilis, hepatitis C (HCV), hepatitis B (HBV), and herpes simplex type 2 (HSV-2) infection. METHODS: A cross sectional sample of 2335 consecutive women was examined during 1996-8. Women were interviewed about risk factors for RTI/STI and tested for Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Treponema pallidum, HIV, HCV, HBV, HSV-1 and HSV-2 infection as well as vaginal candidosis and bacterial vaginosis. Women with antibodies to T pallidum were retested at regular intervals. One year after ending the study seroconversion for syphilis, HBV, HCV, and HSV-2 infection was detected among women initially negative for the respective diseases. RESULTS: The overall prevalence rate of N gonorrhoeae, C trachomatis, T vaginalis, and T pallidum infection was 0.5%, 1.9%, 2.0%, and 2.9% respectively. Overall, 35% of the women had antibodies to hepatitis B core antigen, 0.9% had HCV, and 12% HSV-2 infection. Risk factors for gonorrhoea/C trachomatis infection were a husband not living at home or suspected of being unfaithful. HSV-2 infection was associated with the same risk factors and with a polygamous marriage. The prevalence of HSV-2 infection among women "at risk" was 23%. HIV infection was not diagnosed. Repeated serological examination indicated that only 32% of women with serological evidence of syphilis had active disease. The seroincidences of HBV, HCV, and HSV-2 were 0.03, 0.007, and 0.009 per person year. Seroconversion for syphilis was not observed.

Adolescent↗
PubMed2001

Selected contribution: insulin utilizes NO/cGMP pathway to activate myosin phosphatase via Rho inhibition in vascular smooth muscle.

Our laboratory has recently demonstrated that insulin induces relaxation of vascular smooth muscle cells (VSMCs) by activating myosin-bound phosphatase (MBP) and by inhibiting Rho kinase (Begum N, Duddy N, Sandu OA, Reinzie J, and Ragolia L. Mol Endocrinol 14: 1365-1376, 2000). In this study, we tested the hypothesis that insulin via the nitric oxide (NO)/cGMP pathway may inactivate Rho, resulting in a decrease in phosphorylation of the myosin-bound subunit (MBS(Thr695)) of MBP and in its activation. Treatment of confluent serum-starved VSMCs with insulin prevented thrombin-induced increases in membrane-associated RhoA, Rho kinase activation, and site-specific phosphorylation of MBS(Thr695) of MBP and caused MBP activation. Preexposure to N(G)-monomethyl-L-arginine, a NO synthase inhibitor, and R-p-8-(4-chlorophenylthio)cGMP, a cGMP antagonist, attenuated insulin's inhibitory effect on Rho translocation and restored thrombin-mediated Rho kinase activation and site-specific MBS(Thr695) phosphorylation, resulting in MBP inactivation. In contrast, 8-bromo-cGMP, a cGMP agonist, mimicked insulin's inhibitory effects by abolishing thrombin-mediated Rho signaling and promoted dephosphorylation of MBS(Thr695). Furthermore, expression of a dominant-negative RhoA decreased basal as well as thrombin-induced MBS(Thr695) phosphorylation and caused insulin activation of MBP. Collectively, these results indicate that insulin inhibits Rho signaling by decreasing RhoA translocation via the NO/cGMP signaling pathway to cause MBP activation via site-specific dephosphorylation of its regulatory subunit MBS.

Animals↗
PubMed2001

Causes of childhood deaths in Bangladesh: an update.

UNLABELLED: Knowledge of the causes of child death is important for health-sector planning since they relate to available interventions. Little is known about causes of child death in Bangladesh from the conventional sources since there is no vital registration system and very few deaths are attended by a qualified physician. To determine the cause structure of child deaths, verbal autopsy interviews were conducted in the Bangladesh Demographic and Health Survey (BDHS) 1993/94 national sample. Verbal autopsy is a method of finding out the causes of death based on an interview with the next of kin or other caregivers. Between BDHS 1993/94 and BDHS 1996/97, 1-4-y-old child mortality in Bangladesh declined by about 27.0%. This impressive decline prompted a verbal autopsy study using the BDHS 1996/97 national sample to determine whether the cause structure had changed. The same verbal autopsy instrument and methods to collect the data and the same computer algorithm to assign causes of death were used in both surveys. Comparison of BDHS 1993/94 and 1996/97 cause-specific mortality rates revealed that deaths due to almost all causes had declined, although significantly so only for acute respiratory infections (ARI), persistent diarrhoea and drowning. Deaths due to neonatal tetanus, acute watery diarrhoea and undernutrition had not decreased at all. CONCLUSION: Despite an impressive decline in deaths due to ARI, this condition remains the most important known cause of death in Bangladeshi children. Neonatal tetanus and measles together account for about 10% of deaths in children under 5 y. Further improvements in child survival are possible by improving access to and quality of available child survival interventions.

Algorithms↗
PubMed2000

Inhibition of myogenesis by depletion of the glycogen-associated regulatory subunit of protein phosphatase-1 in rat skeletal muscle cells.

In this study, we examined the role of the glycogen-associated regulatory subunit of protein phosphatase-1 (PP-1(G)) in L6 rat skeletal muscle cell myogenesis. The level of PP-1(G) was depleted by transfection with an inducible antisense-oriented PP-1(G) gene. Western blot analysis of the PP-1(G)-depleted cell line revealed a >90% depletion of PP-1(G) protein and a 45% reduction in cellular PP-1 activity and abolished the ability of L6 myoblasts to differentiate into multinucleated myotubes. PP-1(G)-depleted cells also exhibited a marked reduction in the expression of the differentiation marker myogenin as well as creatine kinase. After 7 days in culture, PP-1(G)-depleted cells sustained myoblast levels of inhibitor of differentiation-2, whereas control L6 cells had a severely lower inhibitor of differentiation-2 level and progressed into myotubes. Myoblasts were unable to exit the cell cycle, as measured by the impaired induction of p27 cyclin-dependent kinase inhibitor, a >2-fold increase in DNA synthesis, and elevated levels of phosphorylated retinoblastoma protein (pRb). Replacement of the PP-1(G) gene restored PP-1(G) protein expression, PP-1 enzymatic activity, and the ability to differentiate into myotubes. We conclude that PP-1(G) plays a definite role in L6 myogenesis via its regulation of PP-1 catalytic activity.

Animals↗
PubMed2000

Elevated expression and activity of protein-tyrosine phosphatase 1B in skeletal muscle of insulin-resistant type II diabetic Goto-Kakizaki rats.

We investigated the cellular mechanism(s) of insulin resistance associated with non-insulin dependent diabetes mellitus (NIDDM) using skeletal muscles isolated from non-obese, insulin resistant type II diabetic Goto-Kakizaki (GK) rats, a well known genetic rat model for type II diabetic humans. Relative to non-diabetic control rats (WKY), insulin-stimulated insulin receptor (IR) autophosphorylation and insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation were significantly inhibited in GK skeletal muscles. This may be due to increased dephosphorylation by a protein tyrosine phosphatase (PTPase). Therefore, we measured skeletal muscle total PTPase and PTPase 1B activities in the skeletal muscles isolated from control rats (WKY) and diabetic Goto-Kakizaki (GK) rats. PTPase activity was measured using a synthetic phosphopeptide, TRDIY(P)ETDY(P)Y(P)RK, as the substrate. Basal PTPase activity was 2-fold higher (P < 0.001) in skeletal muscle of GK rats when compared to WKY. Insulin infusion inhibited skeletal muscle PTPase activity in both control (26.20% of basal, P < 0.001) and GK (25.35% of basal, P < 0.001) rats. However, PTPase activity in skeletal muscle of insulin-stimulated GK rats was 200% higher than hormone-treated WKY controls (P < 0.001). Immunoprecipitation of PTPase 1B from skeletal muscle lysates and analysis of the enzyme activity in immunoprecipitates indicated that both basal and insulin-stimulated PTPase 1B activities were significantly higher (twofold, P < 0.001) in skeletal muscle of diabetic GK rats when compared to WKY controls. The increase in PTPase 1B activity in diabetic GK rats was associated with an increased expression of the PTPase 1B protein. We concluded that insulin resistance of GK rats is accompanied atleast by an abnormal regulation of PTPase 1B. Elevated PTPase 1B activity through enhanced tyrosine dephosphorylation of the insulin receptor and its substrates, may lead to impaired glucose tolerance and insulin resistance in GK rats.

Animals↗
PubMed2000

Role of pericytes in vascular calcification: a review.

Pericytes are defined by their location in vivo; the pericyte partially surrounds the endothelial cell of the microvessel and shares a common basement membrane with it. As an integral part of the microvasculature, pericytes play a fundamental role in maintaining local and tissue homeostasis. Current evidence also suggests that pericytes function as progenitor cells capable of differentiating into a variety of different cell types including osteoblasts, chondrocytes and adipocytes. It is now apparent that cells resembling microvascular pericytes, and termed 'pericyte-like' cells, have a widespread distribution in vivo. Pericyte-like cells have been identified in the inner intima, the outer media, and in the vasa vasora of the adventitia of large, medium and small human arteries (1, 2). Moreover, recent studies have suggested that these cells may be responsible, at least in part, for mediating the calcification commonly associated with atherosclerosis (1, 3, 4). In this review, we a) examine the evidence that microvascular pericytes deposit a bone-like mineralised matrix in vitro, b) compare the morphological and biochemical properties of microvascular pericytes, calcifying vascular cells (CVCs) and 'classical' smooth muscle cells (SMCs) isolated from bovine aorta, c) demonstrate that microvascular pericytes deposit a well-organised matrix of bone, cartilage and fibrous tissue in vivo, and d) discuss recent studies designed to gain a better understanding of how pericyte differentiation is regulated.

Animals↗
PubMed2000

Energy expenditure on household, childcare and occupational activities of women from urban poor households.

This present study attempts to measure the energy cost of activities of women from the poor socio-economic group in India. Women in the age group of 18-40 years (n 98) either working for incomes or classified as homemakers were randomly selected. Time disposition studies were conducted by a 24 h observation of their activities on a typical day. Predominant activities were identified from the activity profiles and standardized for posture and duration. The BMR (Douglas bag method) and energy cost of the activities (Kofranyi-Michaelis meter) were measured by indirect calorimetry. The energy consumption during these activities ranged from 2.94-12.51 kJ/min. The tasks were divided into standard, household, childcare, occupational and other activities. Using the World Health Organization/Food and Agriculture Organization/United Nations University (1985) criteria, attempts were made to categorize the activities into light, moderate and heavy. It was significant that except for walking, the standard activities and occupational work could be classified into the light category (< 2.2 BMR). Most of the household and childcare activities except cooking were classified into the moderate to heavy (2.2-> 2.8 BMR). The energy expenditure of activities did not differ significantly between women with different occupations. This present study provides an important database on energy costs of activities for computing energy requirements of women involved in similar activity patterns.

Adolescent↗
PubMed2000

High glucose and insulin inhibit VSMC MKP-1 expression by blocking iNOS via p38 MAPK activation.

Our laboratory has recently demonstrated a role for the phosphatidylinositol 3-kinase-mediated inducible NO synthase (iNOS) signaling pathway in acute regulation of insulin-induced mitogen-activated protein phosphatase-1 (MKP-1) expression in primary cultures of rat aortic vascular smooth muscle cells (VSMCs) (N. Begum, L. Ragolia, M. McCarthy, and N. Duddy. J. Biol. Chem. 273: 25164-25170, 1998). We now show that prolonged treatment of VSMCs with 100 nM insulin and high glucose (25 mM) for 12-24 h, to mimic hyperinsulinemia and hyperglycemia, completely blocked MKP-1 mRNA and protein expression in response to subsequent acute insulin treatment. To understand the mechanism of insulin resistance induced by high glucose and insulin, we studied the regulation of iNOS protein induction in these cells. Both high glucose and chronic insulin treatment caused a marked impairment of iNOS induction in response to acute insulin. Blocking of signaling via the p38 mitogen-activated protein kinase (MAPK) pathway by prior treatment for 1 h with SB-203580, a synthetic p38 MAPK inhibitor, completely prevented the inhibition of iNOS induced by high glucose and insulin and restored MKP-1 induction to levels observed with acute insulin treatment. In contrast, PD-98059, a MEK inhibitor, had no effect. Furthermore, high glucose and chronic insulin treatment caused sustained p38 MAPK activation. We conclude 1) that chronic insulin and high glucose-induced insulin resistance is accompanied by marked reductions in both iNOS and MKP-1 inductions due to p38 MAPK activation that leads to excessive cell growth and 2) that p38 MAPK/extracellular signal-regulated kinase pathways regulate iNOS induction, thereby controlling MKP-1 expression, which in turn inactivates MAPKs as a feedback mechanism and inhibits cell growth.

Animals↗
PubMed2000

Regulation of myosin-bound protein phosphatase by insulin in vascular smooth muscle cells: evaluation of the role of Rho kinase and phosphatidylinositol-3-kinase-dependent signaling pathways.

In this study, we examined the molecular mechanism of myosin-bound protein phosphatase (MBP) regulation by insulin and evaluated the role of MBP in insulin-mediated vasorelaxation. Insulin rapidly stimulated MBP in confluent primary vascular smooth muscle cell (VSMC) cultures. In contrast, VSMCs isolated from diabetic and hypertensive rats exhibited impaired MBP activation by insulin. Insulin-mediated MBP activation was accompanied by a rapid time-dependent reduction in the phosphorylation state of the myosin-bound regulatory subunit (MBS) of MBP. The decrease observed in MBS phosphorylation was due to insulin-induced inhibition of Rho kinase activity. Insulin also prevented a thrombin-mediated increase in Rho kinase activation and abolished the thrombin-induced increase in MBS phosphorylation and MBP inactivation. These data are consistent with the notion that insulin inactivates Rho kinase and decreases MBS phosphorylation to activate MBP in VSMCs. Furthermore, treatment with synthetic inhibitors of phosphatidylinositol-3 kinase (PI3-kinase), nitric oxide synthase (NOS), and cyclic guanosine monophosphate (cGMP) all blocked insulin's effect on MBP activation. We conclude that insulin stimulates MBP via its regulatory subunit, MBS partly by inactivating Rho kinase and stimulating NO/cGMP signaling via PI3-kinase as part of a complex signaling network that controls 20-kDa myosin light chain (MLC20) phosphorylation and VSMC contraction.

Androstadienes↗
PubMed2000

Diabetes in the Goto-Kakizaki rat is accompanied by impaired insulin-mediated myosin-bound phosphatase activation and vascular smooth muscle cell relaxation.

Our laboratory has demonstrated that insulin rapidly stimulates myosin-bound phosphatase (MBP) activity in vascular smooth muscle cells (VSMCs). In this study, we examined whether diabetes is accompanied by alterations in MBP activation and elucidated the components of the signaling pathway that mediate the effects of diabetes. VSMCs isolated from Goto-Kakizaki (GK) diabetic rats (a model for type 2 diabetes) exhibited marked impairment in MBP activation by insulin that was accompanied by failure of insulin to decrease the phosphorylation of a regulatory myosin-bound subunit (MBS) of MBP and inhibit Rho kinase activity resulting in increased myosin light-chain (MLC)20 phosphorylation and VSMC contraction. In VSMCs isolated from control rats, insulin inactivates Rho kinase and decreases MBS phosphorylation, leading to MBP activation. In addition to this pathway, insulin also appears to activate MBP by stimulating the phosphatidylinositol (PI) 3-kinase/nitric oxide (NO)/cGMP signaling pathway because treatment with the synthetic inhibitors of PI 3-kinase, NO synthase (NOS), and cGMP all blocked insulin's effect on MBP activation, whereas cGMP agonists and sodium nitroprusside (SNP) mimicked insulin's effect on MBP activation. VSMCs from diabetic GK rats exhibit reductions in insulin-mediated induction of inducible NOS protein expression and cGMP generation but normal MBP activation in response to SNP and cGMP agonist. This observation led us to examine the effect of diabetes on the activation status of the upstream insulin-signaling components. Although GK diabetes did not affect insulin-stimulated tyrosine phosphorylation of the insulin receptor or its content, insulin-stimulated insulin receptor substrate (IRS)-1 tyrosine phosphorylation was severely impaired. This was accompanied by marked reductions in IRS-1-associated PI 3-kinase activity. We conclude that insulin stimulates MBP via its regulatory subunit, MBS, by inactivating Rho kinase and stimulating NO/cGMP signaling via PI 3-kinase as part of a complex signaling network that controls MLC20 phosphorylation and VSMC contraction. Defective signaling via Rho kinase and the IRS-1/PI 3-kinase/NOS/cGMP pathway may mediate the inhibitory effects of hyperglycemia and diabetes on MBP activation in this experimental model.

Animals↗
PubMed1999

Role of janus kinase-2 in insulin-mediated phosphorylation and inactivation of protein phosphatase-2A and its impact on upstream insulin signalling components.

Our recent studies indicate that insulin rapidly inactivates serine/threonine protein phosphatase-2A (PP-2A) by increasing tyrosine phosphorylation on the catalytic subunit. The exact mechanism of PP-2A inactivation by insulin in vivo is unclear. The Janus kinase (JAK) family of non-receptor protein tyrosine kinases constitute a novel type of signal-transduction pathway which is activated in response to a wide variety of polypeptide ligands, including insulin. In this study we investigated the potential role of JAK-2 in insulin-mediated tyrosine phosphorylation and inactivation of PP-2A using the rat skeletal muscle cell line L6. Co-immunoprecipitation studies revealed that PP-2A is associated with JAK-2 in the basal state. Insulin treatment did not alter JAK-2 association with PP-2A, but did increase JAK-2-mediated tyrosine phosphorylation of the PP-2A catalytic subunit and therefore inhibited PP-2A enzymic activity. Furthermore, PP-2A is associated with phosphoinositide 3-kinase (PI-3K) in the basal state and insulin treatment increases the catalytic activity of PI-3K bound to PP-2A. Pretreatment with AG-490, a specific JAK-2 inhibitor, and SpcAMP, a cAMP agonist, prevented the insulin-mediated increase in (i) JAK-2 kinase activity, (ii) PP-2A tyrosine phosphorylation, (iii) PP-2A inactivation and restored the enzyme activity to control levels, and (iv) PP-2A and JAK-2-associated PI-3K activity. These observations, together with the fact that insulin rapidly activates JAK-2 in L6 cells, and that this is accompanied by an increase in tyrosine phosphorylation of PP-2A in JAK-2 immunoprecipitates, suggest that insulin controls the activation status of PP-2A by tyrosine phosphorylation via JAK-2. PP-2A inactivation may result in an amplification of insulin-generated signals at the level of PI-3K.

Adipocytes↗
PubMed1999

Effect of an Asp905Tyr mutation of the glycogen-associated regulatory subunit of protein phosphatase-1 on the regulation of glycogen synthesis by insulin and cyclic adenosine 3',5'-monophosphate agonists.

The glycogen-associated regulatory subunit of protein phosphatase-1 (PP-1G) plays a major role in insulin-stimulated glycogen synthesis and thus the regulation of nonoxidative glucose disposal in skeletal muscle. In a general population of Caucasians a polymorphism at codon 905 of PP-1G from an aspartate to tyrosine has been reported to be associated with insulin resistance and hypersecretion. In this report functional studies were performed on rat skeletal muscle L6 cells stably transfected with an Asp905Tyr mutant PP-1G to evaluate the impact of this mutation on cellular responsiveness to insulin and cAMP. Although transfection resulted in a 3-fold increase in mutant PP-1G subunit expression, basal and insulin-stimulated PP-1 catalytic activities were decreased when compared with L6 cells transfected with wild-type PP-1G. The Asp905Tyr mutation resulted in an increase in cellular sensitivity to cAMP agonist, resulting in an inhibition of insulin's stimulatory effect on glycogen synthesis. More importantly, low concentrations of (Bu)2cAMP completely reversed insulin's stimulatory effects on glycogen synthesis when added to insulin-treated cells expressing mutant PP-1G. This was due to a rapid activation of glycogen phosphorylase a and a simultaneous inactivation of glycogen synthase via cAMP-mediated reductions in insulin-stimulated PP-1 catalytic activities. We conclude that an Asp905Tyr mutation of PP-1G is accompanied by a relative increase in sensitivity to cAMP agonists as well as a diminished capacity of the mutant PP-1G to effectively mediate the inhibitory effects of insulin on glycogen breakdown via PP-1 activation.

Animals↗