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Biomedical subjects

M Rahman

Publications and source records attributed to M Rahman.

At least 55 records · Page 3Linked to original sources
PubMed2001

Do better family planning services reduce abortion in Bangladesh?

BACKGROUND: Fertility decline is often associated with an increase in contraception and abortion, but the causal relations are difficult to examine with non-experimental data. We aimed to assess the effects of family planning services on abortion rates in two similar areas. METHODS: We examined trends in overall abortion rates and rates for intended and unintended pregnancies in two similar areas typical of rural Bangladesh. We analysed Matlab Demographic Surveillance System (DSS) data on pregnancy outcomes between 1979 and 1998 in these areas, matching them to survey data on fertility preferences, which enabled us to identify pregnancies as intended or unintended. FINDINGS: Abortion rates were significantly lower in the area with better family planning services compared with the comparison area (1984-86, 2.2 vs 5.2; 1996-98, 2.3 vs 6.8). Abortion of unintended pregnancies is similar in both areas, but the higher levels of contraceptive use in the treatment area have led to lower levels of unintended pregnancy and abortion. The likelihood that an unintended pregnancy will be aborted has increased in both areas but the decrease in unintended pregnancies was sufficiently large in the treatment area to offset this increase. INTERPRETATIONS: Abortion may increase during the fertility transition in less-developed countries as the desire to limit family size increases unless there is widespread availability of quality family planning services.

Abortion, Induced↗
PubMed2001

Diverse transcriptional response of CD4+ T cells to stromal cell-derived factor SDF-1: cell survival promotion and priming effects of SDF-1 on CD4+ T cells.

Stromal cell-derived factor (SDF)-1 is a ligand for the chemokine receptor CXCR4 which is broadly expressed in lymphocytes, but the effects of SDF-1 on T cells are largely unknown. When examined using complementary DNA microarray, up-regulation of genes which are associated with DNA repair, detoxification, apoptosis, cell morphology, cell adhesion, and signal transduction was seen in CD4(+) T cells upon SDF-1 exposure. SDF-1 was shown to promote CD4(+) T cell survival through the phosphatidylinositol 3-kinase (PI3K)- and mitogen-activated protein kinase (MAPK)-cascades without cell cycle progression. The proapoptotic Bcl-2 antagonistic of cell death protein was also seen inactivated by the SDF-1-mediated activation of MAPK-extracellular signal-regulated kinases (MEK)-extracellular signal-regulated kinase-ribosomal S6 kinases- and PI3K-pathways. Moreover, the genes known to be associated with cell survival were up-regulated upon SDF-1 exposure and were linked to the MAPK-MEK and PI3K-pathways. Thus, SDF-1 promotes cell survival by two mechanisms: posttranslational inactivation of the cell death machinery and an increased transcription of cell survival-related genes. SDF-1 also primed resting CD4(+) T cells for cytokine- and TCR-mediated stimuli. These data suggest that the SDF-1-mediated cell survival combined with its priming function would set T cells to respond to immunologic challenges.

CD4-Positive T-Lymphocytes↗
PubMed2001

Effect of ramipril vs amlodipine on renal outcomes in hypertensive nephrosclerosis: a randomized controlled trial.

CONTEXT: Incidence of end-stage renal disease due to hypertension has increased in recent decades, but the optimal strategy for treatment of hypertension to prevent renal failure is unknown, especially among African Americans. OBJECTIVE: To compare the effects of an angiotensin-converting enzyme (ACE) inhibitor (ramipril), a dihydropyridine calcium channel blocker (amlodipine), and a beta-blocker (metoprolol) on hypertensive renal disease progression. DESIGN, SETTING, AND PARTICIPANTS: Interim analysis of a randomized, double-blind, 3 x 2 factorial trial conducted in 1094 African Americans aged 18 to 70 years with hypertensive renal disease (glomerular filtration rate [GFR] of 20-65 mL/min per 1.73 m(2)) enrolled between February 1995 and September 1998. This report compares the ramipril and amlodipine groups following discontinuation of the amlodipine intervention in September 2000. INTERVENTIONS: Participants were randomly assigned to receive amlodipine, 5 to 10 mg/d (n = 217), ramipril, 2.5 to 10 mg/d (n = 436), or metoprolol, 50 to 200 mg/d (n = 441), with other agents added to achieve 1 of 2 blood pressure goals. MAIN OUTCOME MEASURES: The primary outcome measure was the rate of change in GFR; the main secondary outcome was a composite index of the clinical end points of reduction in GFR of more than 50% or 25 mL/min per 1.73 m(2), end-stage renal disease, or death. RESULTS: Among participants with a urinary protein to creatinine ratio of >0.22 (corresponding approximately to proteinuria of more than 300 mg/d), the ramipril group had a 36% (2.02 [SE, 0.74] mL/min per 1.73 m(2)/y) slower mean decline in GFR over 3 years (P =.006) and a 48% reduced risk of the clinical end points vs the amlodipine group (95% confidence interval [CI], 20%-66%). In the entire cohort, there was no significant difference in mean GFR decline from baseline to 3 years between treatment groups (P =.38). However, compared with the amlodipine group, after adjustment for baseline covariates the ramipril group had a 38% reduced risk of clinical end points (95% CI, 13%-56%), a 36% slower mean decline in GFR after 3 months (P =.002), and less proteinuria (P<.001). CONCLUSION: Ramipril, compared with amlodipine, retards renal disease progression in patients with hypertensive renal disease and proteinuria and may offer benefit to patients without proteinuria.

Adrenergic beta-Antagonists↗
PubMed2001

Treatment failure with the use of ciprofloxacin for gonorrhea correlates with the prevalence of fluoroquinolone-resistant Neisseria gonorrhoeae strains in Bangladesh.

Although ciprofloxacin is one of the recommended drugs of choice for the treatment of gonorrhea, in vitro resistance to this drug has been observed in surveillance studies and case reports from many parts of the world, including Bangladesh. However, to our knowledge, there have been no prospective studies of the correlation between in vitro response to the drug and treatment outcome. Therefore, a prospective study of 217 female sex workers in Dhaka, Bangladesh, was conducted to examine the correlation between the in vitro response of Neisseria gonorrhoeae and the outcome of ciprofloxacin treatment. Overall, 37.8% of the gonococcal isolates recovered from female sex workers were resistant to ciprofloxacin, and there was a good correlation between in vitro resistance and treatment failure. These findings suggest that in vitro resistance to ciprofloxacin is predictive of clinical treatment failure in patients with gonorrhea.

Adult↗
PubMed2001

A repressor element in the 5'-untranslated region of human Pax5 exon 1A.

B-cell-specific activator protein (BSAP) encoded by the Pax5 gene plays a critical role during B-cell development. We have analyzed the 5'-flanking region plus the 5'-untranslated region (5'-UTR) of human Pax5 exon1A to clarify its regulatory mechanisms. Functional dissection of these regions by luciferase reporter assays indicated that a cluster of regulatory elements acts as a strong repressor between +320 and +453. Insertion of this segment between the heterologous simian virus 40 (SV40) promoter and the luciferase gene in both the sense and reverse orientation sharply reduced the luciferase activity, but insertion into the upstream of the SV40 promoter did not. This suggests that this segment must be located in the 5'-UTR to function effectively. A search through databases with the sequence of this segment did not reveal any known DNA binding factor site. Electrophoretic gel mobility shift assay (EMSA) experiments demonstrated that unknown factors bound to the fragment +408 to +429. Insertion of this fragment between the SV40 promoter and the reporter gene strongly suppressed the luciferase activity. Competitive EMSA indicated that the region between nucleotides +413 and +427 encompassed the binding site of the unknown factors and was hence regarded as a repressor element. Mutagenesis in this element significantly recovered reporter gene activity. These results suggest that the segment +320 to +453, especially the repressor element +413 to +427, in the 5'-UTR is involved in the regulation of Pax5 gene expression.

Base Sequence↗
PubMed2001

Hypertension in hemodialysis patients.

Hypertension is very common and often poorly controlled in patients undergoing chronic hemodialysis. While high blood pressure has been documented to adversely impact several intermediate outcomes of cardiovascular disease, whether hypertension is an independent risk factor for mortality in this population is not clear. Expansion of extracellular fluid volume is the major pathophysiologic mechanism for the development of hypertension in these patients; however, alterations in other humoral mechanisms also play a significant role. Optimization of volume status is, therefore, the cornerstone of therapy with additional use of antihypertensive medications as needed. Good quality prospective studies are urgently needed to define the measurement techniques and blood pressure goals, and to develop therapeutic strategies for more effective management of hypertension in this high-risk population.

Blood Pressure↗
PubMed2001

Estimating the effect of bystander-initiated cardiopulmonary resuscitation in Japan.

Low incidence of bystander-initiated cardiopulmonary resuscitation (CPR) is allegedly responsible for poor survival from out-of-hospital cardiac arrest (OHCA) in Japan. This study was conducted to determine significant predictors for survival after collapse-witnessed OHCA of presumed cardiac etiology to investigate the impact of bystander-initiated CPR. Logistic regression analysis of OHCA of presumed cardiac etiology was performed on retrospective data sets from three Japanese suburban communities. All arrest incidents were witnessed and occurred prior to the arrival of EMS personnel. Outcome measure was survival to discharge. Initial electrocardiogram (ECG) rhythm (ventricular fibrillation (VF) or not), interval from collapse to CPR (within 5 min or not), and initial ECG rhythm/collapse-to-CPR interval interaction were significantly associated with survival. Patient age (70 years or less/over 70 years), interval from collapse to EMS response, and bystander-initiated CPR were significantly associated with VF in an initial ECG. The effectiveness of bystander-initiated CPR for OHCA can be successfully predicted based on the interval from collapse to CPR and initial ECG rhythm. The increase in the proportion of bystander-initiated CPR from the present level of 20-50% would be expected to rescue another 1800 victims of OHCA per year in Japan.

Aged↗
PubMed2001

A forced titration study of antihypertensive efficacy of candesartan cilexetil in comparison to losartan: CLAIM Study II.

An 8-week, multicentre (72 sites in the US), double-blind, randomised, parallel group, forced titration study compared the antihypertensive efficacy of candesartan cilexetil and losartan. A total of 611 patients with essential hypertension (diastolic blood pressure 95 to 114 mm Hg) were randomised initially to candesartan cilexetil 16 mg once daily or losartan 50 mg once daily. After 2 weeks of randomised treatment, the doses of candesartan cilexetil and losartan were doubled to 32 mg and 100 mg once daily and continued respectively for 6 weeks. At week 8, candesartan cilexetil lowered the blood pressure (BP) at 24 h (trough), 6 h (peak) and 48 h post dose to a significantly greater extent (P < 0.05) than losartan: candesartan cilexetil lowered trough BP by 13.4/10.5 mm Hg, peak BP by 15.5/12.9 mm Hg and 48-h BP by 10.5/9.9 mm Hg compared to a reduction of trough BP by 10.1/9.1 mm Hg, peak BP by 12.0/9.5 mm Hg, and 48-h BP by 5.9/7.0 mm Hg by losartan. The responder and control rates were numerically higher in the candesartan cilexetil group, but the differences did not reach statistical significance; the responder rates were 58.8% for the candesartan cilexetil group and 52.1% for the losartan group and control rates were 49.0% for the candesartan cilexetil group and 44.6% for the losartan group. Overall, both treatment regimens were well tolerated. A total of 15 of the 611 (2.5%) patients withdrew from the study due to an adverse event, including nine (2.9%) in the candesartan cilexetil group and six (2.0%) in the losartan group. In conclusion, this forced titration study confirms that candesartan cilexetil is more effective in lowering BP than losartan when compared at once daily maximum doses.

Antihypertensive Agents↗
PubMed2001

Developmental regulation and overexpression of the transcription factor AP-2, a potential regulator of the timing of Schwann cell generation.

There is now evidence from in vivo and in vitro studies that the rate of Schwann cell generation is regulated by the balance of two opposing signals, beta neuregulins and endothelins. The beta neuregulins promote the development of precursors to Schwann cells whereas endothelins retard it through an action on endothelin-B receptors. The present work has shown additional controls of this transition, and implicates AP-2 transcription factors, in particular AP-2 alpha, as negative regulators of Schwann cell generation. We found that both AP-2 alpha and AP-2 gamma are present in early embryonic nerves, whereas AP-2 beta was not. Isoform-specific analysis of AP-2 alpha showed that isoform 3 was most abundant with isoforms 1 and 2 present in lesser amounts; isoform 4 was absent. Maximal AP-2 alpha and AP-2 gamma mRNA expression occurred at embryonic day (E) 12/13 in the mouse and at E14/15 in the rat, which correlates with the presence of Schwann cell precursors in the nerve. In both rats and in mice, in vivo and in vitro, downregulation of AP-2 alpha mRNA and protein coincided with one of the main steps in Schwann cell development, the precursor-Schwann cell transition. Moreover, Schwann cell generation was delayed if this downregulation was prevented by enforced expression of AP-2 alpha in precursors. These studies suggest that AP-2 is involved in the control of the timing of Schwann cell development.

Animals↗
PubMed2001

Hydrologic modeling of aquatic plant treatment systems polishing dairy lagoon effluents.

In this study, a mathematical model of the hydrologic balance of an aquatic plant treatment system (APTS) has been developed. The mass balance approach has been adopted and the major components of the water balance, such as precipitation, evapotranspiration (ET) and percolation have been incorporated into the model. For estimation of ET for duckweed and water hyacinth plants, mathematical relationships were established between ET and pan evaporation using data collected at the site. The observed ET rates of water hyacinths were up to 66% higher than the pan evaporation rates. But for duckweed, the observed ET rates were 10 to 20% lower than the pan evaporation rates. Using the available historic precipitation and pan evaporation data, several computer simulations of the model were run to estimate the HLR and HRT of the ponds under different design requirements. The results indicate that aquatic ponds with water hyacinths can operate at greater HLR's than ponds supporting duckweed. For a zero discharge system, the allowable HLR for a water hyacinth pond was found to be 5 times that of a pond containing duckweed.

Agriculture↗
PubMed2001

Economic evaluation of universal BCG vaccination of Japanese infants.

BACKGROUND: The international controversy surrounding the use and effectiveness of the Bacillus Calmette-Guérin (BCG) vaccine and the low incidence of tuberculosis (TB) among Japanese children prompted this study. METHODS: We compared 'universal BCG vaccination' with 'no vaccination at all' using a cost-effectiveness analysis. The study population was a hypothetical cohort comprising a total of 1.2 million infants born in 1996 at locations all over Japan. A model was developed to calculate the number of TB cases prevented by the vaccination programme. Assuming 40-80% overall vaccine efficacy (64-86% for TB-meningitis) and 10 years of protection, we calculated the cost and number of immunizations required to prevent one child from developing TB, the total number of TB cases averted by vaccination and total costs required for the programme. RESULTS: Based on an assumption of flexible vaccine efficacy (40-80%), we estimated that 111-542 TB cases including 10-27 of TB-meningitis would be prevented during the 10 years after BCG vaccination among the cohort of infants born in 1996. About US$35 950-175 862 or 2125-10 399 immunizations would be required to prevent one child from developing TB. Sensitivity analyses covering a wide duration of protection, incidence of TB, vaccine coverage and discount rate, revealed that other than vaccine efficacy, the cost of preventing a single case of TB is highly sensitive to the duration of BCG protection and TB incidence. CONCLUSION: The cost per case of TB prevented is heavily dependent on vaccine efficacy and the duration of protection, and is high compared with the cost of treating one child who has developed TB.

BCG Vaccine↗
PubMed2001

Quantitative radiographic analysis of fiber reinforced polymer composites.

X-ray radiographic examination of the bone fracture healing process is a widely used method in the treatment and management of patients. Medical devices made of metallic alloys reportedly produce considerable artifacts that make the interpretation of radiographs difficult. Fiber reinforced polymer composite materials have been proposed to replace metallic alloys in certain medical devices because of their radiolucency, light weight, and tailorable mechanical properties. The primary objective of this paper is to provide a comparable radiographic analysis of different fiber reinforced polymer composites that are considered suitable for biomedical applications. Composite materials investigated consist of glass, aramid (Kevlar-29), and carbon reinforcement fibers, and epoxy and polyether-ether-ketone (PEEK) matrices. The total mass attenuation coefficient of each material was measured using clinical X-rays (50 kev). The carbon fiber reinforced composites were found to be more radiolucent than the glass and kevlar fiber reinforced composites.

Biocompatible Materials↗
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

Renal interstitial adenosine metabolism during ischemia in dogs.

The present study was conducted to determine the metabolism of renal interstitial adenosine under resting conditions and during ischemia. By using a microdialysis method with HPLC-fluorometric analysis, renal interstitial concentrations of adenosine, inosine, and hypoxanthine were assessed in pentobarbital-anesthetized dogs. Average basal renal interstitial concentrations of adenosine, inosine, and hypoxanthine were 0.18 +/- 0.04, 0.31 +/- 0.05, and 0.35 +/- 0.05 micromol/l, respectively. Local inhibition of adenosine kinase with iodotubercidin (10 micromol/l in perfusate) or inhibition of adenosine deaminase with erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA; 100 micromol/l in perfusate) did not change adenosine concentrations in the nonischemic kidneys (0.18 +/- 0.04 and 0.24 +/- 0.05 micromol/l, respectively). On the other hand, treatment with iodotubercidin+EHNA significantly increased adenosine concentration (0.52 +/- 0.07 micromol/l) with significant decreases in inosine and hypoxanthine levels (0.13 +/- 0.03 and 0.19 +/- 0.04 micromol/l, respectively). During 30 min of ischemia, adenosine, inosine, and hypoxanthine were significantly increased to 0.76 +/- 0.29, 2.14 +/- 0.45, and 21.8 +/- 4.7 micromol/l, respectively. The treatment with iodotubercidin did not alter ischemia-induced increase in adenosine (0.84 +/- 0.18 micromol/l); however, EHNA alone markedly enhanced adenosine accumulation (13.54 +/- 2.16 micromol/l), the value of which was not augmented by an addition of iodotubercidin (15.80 +/- 1.24 micromol/l). In contrast, ischemia-induced increases in inosine and hypoxanthine were inversely diminished by the treatment with iodotubercidin+EHNA (0.90 +/- 0.20 and 9.86 +/- 1.96 micromol/l, respectively). These results suggest that both adenosine kinase and adenosine deaminase contribute to the metabolism of renal interstitial adenosine under resting conditions, whereas adenosine produced during ischemia is mainly metabolized by adenosine deaminase and the rephosphorylation of adenosine by adenosine kinase is small.sent

Adenine↗
PubMed2001

Advanced textile composite ring for Ilizarov external fixator system.

The use of a radiolucent composite material permits easier and more accurate radiographic evaluation of the bone healing process, and results in a much lighter system. The finite element method (FEM) is employed to determine the worst possible in-service loading condition and the ring dimensions are modified accordingly. Half-ring prototypes are produced using two types of composite materials: knitted aramid fibre fabric reinforced epoxy and random short carbon (RSC) fibre reinforced epoxy. The in-plane compressive strength and axial stiffness of the complete frame are tested according to ASTM specifications. The performance is evaluated, and compared with an existing system in simulated in-service conditions.

Biomechanical Phenomena↗
PubMed2001

Pseudohyperkalaemia caused by recentrifugation of blood samples after storage in gel separator tubes.

Because hyperkalaemia above a certain level is life-threatening, erroneous interpretation of serum potassium concentration may misguide and complicate diagnostic procedures. We investigated a number of cases with pseudohyperkalaemia, which was assumed to have been caused by the recentrifugation of blood samples after storage in gel separator tubes. The time trend of serum potassium concentration was explored before (January-March 1997) and after (May-July 1997) ceasing the practice of recentrifuging blood samples after overnight storage. Next, we conducted an experiment on a volunteer's serum. The sample was divided into two groups and centrifuged once (control group) or twice (recentrifugation group). For both groups, serum potassium concentrations were measured immediately, and at 24, 48 and 72 h. For the recentrifugation group, the second centrifugation was done just before the measurement. The time series study showed that the mean serum potassium concentrations measured after overnight storage were 4.68 (95% CI: 4.60-4.76) mmol/L before and 4.14 (4.07-4.20) mmol/L after ceasing the practice of recentrifugation. The experiment showed that the mean serum potassium concentrations in the control group versus the recentrifugation group were 3.95 (95% CI: 3.89-4.01) mmol/L versus 4.05 (3.92-4.17) immediately (P=0.0979), 3.95 (3.89-4.01) versus 5.95 (5.61-6.29) at 24 h (P=0.0001), 4.13 (4.05-4.22) versus 6.90 (6.46-7.34) at 48 h (P=0.0001), and 4.22 (3.85-4.58) versus 7.61 (6.94-8.30) at 72 h (P<0.0001). Recentrifugation of blood samples after storage causes a spurious rise in serum potassium concentration to the degree of clinical significance. Clinicians and biochemists should take appropriate measures to stop this practice.

Artifacts↗
PubMed2001

Blood lead levels of primary school children in Dhaka, Bangladesh.

Dhaka, Bangladesh, has one of the highest air lead levels in the world. In February 2000, we evaluated children at five primary schools in Dhaka to determine blood lead (BPb) levels, sources of environmental exposure, and potential risk factors for lead poisoning. Selected schools represented a range of geographic and socioeconomic strata. A total of 779 students 4-12 years of age participated. The mean BPb level was 15.0 microg/dL (range 4.2-63.1 microg/dL). Most students (87.4%) had BPb levels above the Centers for Disease Control and Prevention's level of concern (10 microg/dL). Elevated BPb levels correlated with soil eating [odds ratio (OR) = 3.31; 95% confidence interval (CI), 1.30-8.39], low parental education (OR = 2.72; 95% CI, 1.97-3.75), living close to major roads (OR = 2.30; 95% CI, 1.23-4.29), and increasing age (OR = 1.11; 95% CI, 1.06-1.16). BPb levels measured were similar to those in other countries that use leaded gasoline. No other potential sources of lead exposure were consistently identified. Combustion of leaded gasoline is the main source of lead exposure in Dhaka, resulting in ubiquitous contamination of the environment. The increase in BPb levels with age, a finding contrary to observations in the United States and Australia, may be related to increased outdoor activities. The Bangladeshi government recently announced a plan to eliminate leaded gasoline. Baseline BPb surveys are critical to develop and evaluate intervention policies. Strategies to reduce BPb levels need to address variations in socioeconomic status, construction type and location of housing, and levels of hygiene.

Air Pollution↗