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Biomedical subjects

M Rahman

Publications and source records attributed to M Rahman.

At least 73 records · Page 4Linked to original sources
PubMed2001

Role of nitric oxide in regional blood flow in angiotensin II-induced hypertensive rats.

The present study was designed to evaluate the contribution of nitric oxide (NO) to regional hemodynamics during the early phase of angiotensin II (Ang II)-induced hypertension. The responses of regional blood flow to chronic NO synthase inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME) were assessed using radioactive microspheres in conscious Ang II-infused hypertensive rats. Ang II-infused rats (270 ng/kg/min, subcutaneously for 12 days: n=11) showed higher mean arterial pressure (MAP: 153+/-4 mmHg) and total peripheral resistance (TPR: 1.61+/-0.06 mmHg/min/ml), and lower cardiac output (CO: 102+/-3 ml/min) than vehicle-infused normotensive rats (115+/-2 mmHg, 0.96+/-0.05 mmHg/min/ml and 130+/-7 ml/min, n=11, respectively). The blood flow rates in the brain, spleen, large intestine and skin were significantly reduced in Ang III-infused rats compared with vehicle-infused rats, while those in the lung, heart, liver, kidney, adrenal gland, small intestine, and skeletal muscle were similar. Treating Ang II-infused rats with L-NAME (75 mg/l in drinking water for 10 days, n=11) resulted in higher MAP (166+/-6 mmHg) and TPR (1.89+/-0.18 mmHg/min/ml) and lower CO (87+/-7 m/min) than untreated Ang II-infused rats. L-NAME-treated Ang II-infused rats showed widespread increases in regional vascular resistance and reduced blood flow rates in the kidney (3.81+/-0.27 ml/min/g) and skeletal muscle (0.20+/-0.03 ml/min/g) compared with untreated Ang II-infused rats (6.88+/-0.27 and 0.33+/-0.04 ml/min/g, respectively). However, there were no significant differences in the flow rates of other organs investigated between these animals. An NO donor, (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409: 30 microg/kg/min, i.v.), significantly decreased MAP (110+/-6 mmHg) and TPR (1.23+/-0.18 mmHg/min/ml) without significant changes in CO (89+/-9 ml/min) in L-NAME-treated Ang II-infused rats. Furthermore, FK409 partially reversed blood flow rates in the kidney (4.72+/-0.40 ml/min/g) and skeletal muscle (0.25+/-0.02 ml/min/g)in these animals. These results suggest that NO counteracts, at least in part, the vasoconstrictor effects of elevated Ang II levels in renal and skeletal muscle vascular beds, and is an important modulator in the regulation of blood flow to these organs during the development of Ang II-induced hypertension.

Angiotensin II↗
PubMed2001

Benidipine dilates both pre- and post-glomerular arteriole in the canine kidney.

The aim of the present study was to determine the effects of benidipine on renal function and whether benidipine may dilate the efferent arteriole as well as the afferent arteriole of the canine kidney. The effects of benidipine on the renal segmental vascular resistance were estimated using Gomez's formula with some modification. The renal hemodynamic action of benidipine was also compared with that of amlodipine. Intrarenal arterial injection of benidipine at a dose of 3 microg/kg resulted in a significant increase in renal blood flow (RBF), urine flow and urinary excretion of sodium, but not in glomerular filtration rate (GFR). Amlodipine at a dose of 300 microg/kg also increased RBF, urine flow and urinary excretion of sodium to a significant degree equivalent to that by benidipine. However, in contrast to benidipine, amlodipine significantly increased GFR. After the administration of benidipine, autoregulation of RBF and GFR was relatively maintained and the renal perfusion pressure (RPP)-RBF relation shifted upward; that is, RBFs at 75 and 50 mmHg were maintained at a higher level than those of the control. In contrast to benidipine, amlodipine diminished the autoregulation of RBF and GFR. RBFs at 75 and 50 mmHg were not different from those of the control. The afferent and efferent arteriolar resistance (Ra and Re) were calculated based on the RPP-RBF and RPP-GFR relations. Benidipine reduced both Ra and Re, but amlodipine selectively reduced Ra. Benidipine increased RBF but not GFR via the dilation of both afferent and efferent arterioles. Thus, benidipine has unique renal hemodynamic actions which differ from those by most calcium antagonists.

Animals↗
PubMed2001

Prednisolone sodium succinate down-regulates BSAP/Pax5 and causes a growth arrest in the Nalm6 pre-B cell line.

Glucocorticoids (GCs) induce growth arrest and apoptosis of B lineage cells, especially pre-B and immature B cells, but little is known about this mechanism. Since B cell-specific activator protein (BSAP) encoded by the Pax5 gene is an essential transcription factor for B-cell proliferation, we have investigated the effect of prednisolone sodium succinate (Pss) on BSAP expression in several human leukemic B lineage cell lines. Pss caused growth arrest of Nalm6 (pre-B) cells, but this is not the case for 207 (pro-B) and Raji (mature B) cells. In Nalm6 cells, the growth rate and the amount of BSAP bound to its recognition sequence decreased in proportion to the Pss dose. Pss also reduced the expression level of BSAP as well as of Pax5 mRNA. These data suggest that the suppression of Pax5/BSAP may be involved in the GCs-induced growth arrest of pre-B cells.

B-Lymphocytes↗
PubMed2001

Factors related to biomedical research productivity in Asian countries.

By and large, biomedical research is not a priority sector in Asian countries due to many factors. Lack of resources and trained manpower are certainly among these factors. We investigated the factors related to biomedical research productivity in Asian countries based on Medline data. The number of biomedical articles published in the indexed journals from each country of Asia and Oceania during 1990-1998 was used as a surrogate of total biomedical research productivity. Multiple regression analysis revealed that low gross national product per capita (p<0.013), insufficient number of physicians (p<0.047), and inadequate public spending on the health sector (p<0.049) were responsible for the meager number of biomedical publications in Asian countries.

Asia↗
PubMed2001

The defibrillation system of basic emergency medical technicians in Japan: a comparison with other systems from a 14-year review of out-of-hospital cardiac arrest reports.

Although seven years have passed after basic emergency medical technician (EMT) defibrillation system was introduced in Japan, the overall survival for out-of-hospital cardiac arrest (OHCA) remains poor. We investigated factors leading to such an unanticipated result in Japan by comparing the data of OHCA in Japan with those in other countries. We obtained population-based OHCA data from three communities in Japan. We also performed a comprehensive literature and manual search to identify reports that included rates for incidence and survival or provided sufficient data for the calculation of these rates of OHCA. Statistical analysis was performed to compare survival and incidence rates between the communities. We identified 36 articles from 16 countries by a comprehensive literature search. There was no significant difference in incidence and survival rates among communities in Japan. Although the incidence rate of collapse-witnessed OHCA with ventricular fibrillation (VF) was much lower in Japan than western countries, the proportions of survival from it were comparable to those. Basic-EMT defibrillation system in Japan has yielded excellent result in terms of the survival of VF cases. However, much lower proportion of VF to all cases is responsible for lower overall rates of survival from OHCA in Japan.

Chi-Square Distribution↗
PubMed2001

Evaluation of tuberculosis control by periodic or routine susceptibility testing in previously treated cases.

SETTING: A national tuberculosis control programme (NTP) disposing of baseline drug resistance rates and using 2EHRZ/6TH in the treatment of new cases. OBJECTIVE: To estimate the extent of drug resistance created by the NTP. DESIGN: Resistance rates in 2EHRZ/6TH failure and relapse cases were compared to baseline, and resistance profiles of repeat isolates were checked. Numbers of observed resistant failures were compared to numbers expected due to pre-existing resistance. Trends of resistance in combined new and previously treated cases were extrapolated. RESULTS: High drug resistance rates were observed. Changes in resistance to streptomycin, the virtual absence of documented acquired resistance and a close match of observed with expected resistant failures all indicated accumulation of primary drug resistance as the main mechanism. Resistance in relapse/failure cases showed a significantly declining trend, and estimated combined drug resistance decreased rapidly. CONCLUSIONS: Drug resistance in previously treated cases seems to consist of passed-on primary rather than true acquired resistance. A one-time survey is thus confusing, but continuous routine testing may constitute the best drug resistance monitoring method. Cases previously treated with short-course chemotherapy may show drug resistance much more frequently than generally assumed, and all should receive a re-treatment regimen. The 2EHRZ/6TH regimen proved very safe under field conditions, causing no 'amplification' towards multidrug resistance and almost no acquired isoniazid resistance. Implementation of this regimen, together with a standardised re-treatment regimen, seemed to rapidly reduce isoniazid as well as multidrug resistance levels, despite the fact that directly observed treatment was not strictly applied.

Antitubercular Agents↗
PubMed2001

Divalent cations in women with PCOS: implications for cardiovascular disease.

Polycystic ovary syndrome (PCOS) patients are known to have a high incidence of insulin resistance and glucose intolerance and tend to be at eventual high risk of hypertension, diabetes mellitus and cardiovascular disease. It has been repeatedly shown that a low serum ionized magnesium (Mg2+) and a high ionized calcium to magnesium (Ca2+/Mg2+) ratio is often associated with insulin resistance, cardiovascular problems, diabetes mellitus and hypertension. We were therefore interested in assessing the serum divalent cation profile of PCOS patients compared with that of normal women of similar age. We found significantly lower serum Mg2+ and total magnesium and a significantly higher serum Ca2+/Mg2+ ratio in the PCOS patients compared with the controls. No correlation was found, however, between the serum concentrations of steroid hormones (estrogen, progesterone and testosterone), or any of the cations in the PCOS patients or the controls.

Adult↗
PubMed2001

Three case definitions of malaria and their effect on diagnosis, treatment and surveillance in Cox's Bazar district, Bangladesh.

In countries where malaria is endemic, routine blood slide examinations remain the major source of data for the public health surveillance system. This approach has become inadequate, however, as the public health emphasis has changed from surveillance of laboratory-confirmed malaria infections to the early detection and treatment of the disease. As a result, it has been advocated that the information collected about malaria be changed radically and should include the monitoring of morbidity and mortality, clinical practice and quality of care. To improve the early diagnosis and prompt treatment (EDPT) of malaria patients, three malaria case definitions (MCDs) were developed, with treatment and reporting guidelines, and used in all static health facilities of Cox's Bazar district, Bangladesh (population 1.5 million). The three MCDs were: uncomplicated malaria (UM); treatment failure malaria (TFM); and severe malaria (SM). The number of malaria deaths was also reported. This paper reviews the rationale and need for MCDs in malaria control programmes and presents an analysis of the integrated surveillance information collected during the three-year period, 1995-97. The combined analysis of slide-based and clinical data and their related indicators shows that blood slide analysis is no longer used to document fever episodes but to support EDPT, with priority given to SM and TFM patients. Data indicate a decrease in the overall positive predictive value of the three MCDs as malaria prevalence decreases. Hence the data quantify the extent to which the mainly clinical diagnosis of UM leads to over-diagnosis and over-treatment in changing epidemiological conditions. Also the new surveillance data show: a halving in the case fatality rate among SM cases (from 6% to 3.1%) attributable to improved quality of care, and a stable proportion of TFM cases (around 7%) against a defined population denominator. Changes implemented in the EDPT of malaria patients and in the surveillance system were based on existing staff capacity and routine reporting structures.

Bangladesh↗
PubMed2001

Emergence of multidrug-resistant Salmonella Gloucester and Salmonella typhimurium in Bangladesh.

Infections due to non-typhoid Salmonella, resistant to antibiotics, have recently emerged as an important health problem worldwide. Antibiotic resistance was studied by the disc-diffusion method among 3,876 (2.78%) non-typhoid Salmonella isolates cultured from 139,279 faecal samples in a diarrhoea treatment centre in Dhaka, Bangladesh, during 1989-1996. Of 499 salmonellae isolated in 1989, serogroup C (1.12%) was the most common, followed by Salmonella Typhi (0.72%) and serogroup B (0.71%). Isolation rate of serogroup B increased significantly to 2.18% (p < 0.01) in 1992 compared to 0.56% in 1991, 2.86% in 1995, and 2.48% in 1996. Serotyping of 194 serogroup B isolates revealed Salmonella Typhimurium (52%) and Salmonella Gloucester (45%) as predominant serotypes. Resistance to ampicillin (A), chloramphenicol (C), and trimethoprim-sulphamethoxazole (Sxt) (R type-ACSxt) increased to 89-100% during 1992-1996 from 20-28% during 1989-1991 (p < 0.01) among S. Typhimurium and S. Gloucester isolates. In 1993, 8-10% of the strains of both the serotypes, resistant to ampicillin, chloramphenicol, and trimethoprim-sulphamethoxazole, acquired resistance to ceftriaxone (Cr) (R type-ACSxtCr), which increased to 85-92% in 1996 (p < 0.01). All were susceptible to ciprofloxacin. A 157-kb conjugative plasmid transferred R type-ACSxt from both the serotypes to Escherichia coli K-12. The findings of the study suggest the emergence of multidrug-resistant S. Gloucester and S. Typhimurium for the first time as a significant health problem in Bangladesh, and surveillance is essential to monitor the resistant non-typhoid Salmonella and identify its sources and modes of transmission.

Anti-Bacterial Agents↗
PubMed2001

Rapid detection of Haemophilus influenzae type b in Bangladeshi children with pneumonia and meningitis by PCR and analysis of antimicrobial resistance.

A polymerase chain reaction (PCR) assay with primers from 'bexA' gene was compared with culture for the detection of Haemophilus influenzae type b (Hib) in clinical samples from children with pneumonia and meningitis. Of 200 sera (180 from pneumonia, 20 from non-pneumonia patients) tested by PCR (serum-PCR), Hib was detected in 15 of 16 blood culture-positive and in 6 blood culture-negative pneumonia cases. When compared with the results of blood culture, serum-PCR had sensitivity, specificity, and accuracy index of 93.7%, 96.7%, and 96.5% respectively. Of 120 cerebrospinal fluid (CSF) samples from meningitis patients tested by culture and PCR (CSF-PCR), the latter method could detect Hib in all 15 culture-positive and in 8 of 105 culture-negative cases, showing sensitivity, specificity, and accuracy index of 100%, 92.4%, and 94.4% respectively. The PCR result was available within a day. Antimicrobial susceptibility of Hib was determined by the disc-diffusion method. High rate of resistance to ampicillin (54.8%), chloramphenicol (48.4%), and co-trimoxazole (80.6%) was observed among 31 invasive Hib isolates with resistance to all 3 drugs (multiresistance) in 48.4% of the isolates. All the Hib isolates were susceptible to ceftriaxone. The study has shown that PCR is a rapid, sensitive and specific diagnostic test for Hib from clinical samples, and a combination of culture and PCR is necessary for the detection of Hib infections to the maximum extent for case management to reduce morbidity, mortality, and complications of the invasive Hib infections. A high prevalence of multiresistant Hib strains is a matter of concern.

Bangladesh↗
PubMed2001

Effect of oestrogen replacement therapy on bone mass in post-menopausal Bangladeshi women.

The female population comprises 48.66% of our total population, of which 10.30% are above the age of 49, many of whom are post-menopausal. Menopause is associated with bone-loss and its consequences. Hormone replacement therapy (HRT), particularly replacement of estrogen, prevents bone-loss. We undertook this prospective case-controlled study to find out whether or not HRT is beneficial to our women. A total of 106 patients were studied, amongst them 60 were cases and 46 were controls. The women in the first group were given either conjugated equine estrogen alone (surgical menopause group) or conjugated equine estrogen plus cyclical progesterone (natural menopause group). Results showed that there was 4.29% increase in bone mineral density in women who received hormone replacement therapy (HRT). This increase was 5.23% in early and 3.56% in late menopause group. Women with natural menopause gained more bone mass (4.22%) than women with surgical menopause (3.9%). Our results also showed that women who denied HRT (controls) lost bone mass (5.26%), the loss was more in those with surgical menopause (6.24%) than those with natural menopause (4.87%). Therefore it can be concluded that post-menopausal hormone replacement therapy prevents bone-loss. However, to evaluate the beneficial effect of long-term HRT, further studies with larger samples are recommended.

Bangladesh↗
PubMed2000

Increase of androgen-induced cell death and androgen receptor transactivation by BRCA1 in prostate cancer cells.

Although mutations of the breast cancer susceptibility gene 1 (BRCA1) may play important roles in breast and prostate cancers, the detailed mechanism linking the functions of BRCA1 to these two hormone-related tumors remains to be elucidated. Here, we report that BRCA1 interacts with androgen receptor (AR) and enhances AR target genes, such as p21((WAF1/CIP1)), that may result in the increase of androgen-induced cell death in prostate cancer cells. The BRCA1-enhanced AR transactivation can be further induced synergistically with AR coregulators, such as CBP, ARA55, and ARA70. Together, these data suggest that the BRCA1 may function as an AR coregulator and play positive roles in androgen-induced cell death in prostate cancer cells and other androgen/AR target organs.

Androgens↗
PubMed2000

Interdialytic weight gain, compliance with dialysis regimen, and age are independent predictors of blood pressure in hemodialysis patients.

Hypertension is a common problem in patients undergoing chronic hemodialysis. The purpose of this study is to identify the clinical and demographic factors independently associated with blood pressure in this population. Data collected for the Dialysis Morbidity and Mortality Study Wave 1 by the US Renal Data System were analyzed. The mean predialysis blood pressure for this cohort of 5,369 patients was 149/79 mm Hg. Sixty-three percent of the patients were hypertensive; 27%, 25%, and 11% had stages 1, 2, and 3 hypertension, respectively. Young age, black race, male sex, diabetes as cause of end-stage renal disease, erythropoietin therapy, and smoking were associated with higher blood pressure in the univariate analysis. Patients skipping or shortening one or more dialysis treatments had higher blood pressure. The presence of congestive heart failure and coronary heart disease was associated with lower blood pressure. On multivariate analysis, high interdialytic weight gain, noncompliance with dialysis regimen, and younger age were independent predictors of higher blood pressure. In summary, hypertension is common and poorly controlled in patients undergoing chronic hemodialysis. Greater interdialytic weight gain and noncompliance with dialysis regimen are independently associated with higher blood pressure, and advancing age is associated with lower blood pressure levels in this population. Therapeutic regimens emphasizing reduction of interdialytic weight gain and improved compliance with the dialysis regimen need to be evaluated for improving the management of hypertension. The effect of age and other comorbid conditions, particularly cardiovascular disease, must be considered while studying the relationship between blood pressure and mortality in patients undergoing chronic hemodialysis.

Age Factors↗
PubMed2000

Bidi smoking and health.

Bidi, made of low-grade tobacco, is popular among rural folk and the urban poor, in the South Asian region. The objectives of this study were: (1) to assess the extent of bidi smoking in different countries; (2) to compare its smoke and health hazards with conventional cigarettes and; (3) to recommend preventive measures. English language articles were identified through a MEDLINE computerised search (1966-1998) using the term 'bidi', 'beedi', 'beedie', 'biri' and manually in order to collate all the available information and to present a descriptive epidemiological profile. The prevalence of bidi smoking was found to be 21-56% among men in South Asian countries with very little information available about women. Concentrations of nicotine, tar and other toxic agents in the smoke are higher for bidi than for other cigarettes. Bidi smoking is also considered to cause about 2-3 times greater nicotine and tar inhalation than do conventional cigarettes, due to the poor combustibility of the bidi wrapper and greater puff frequency needed to keep the bidi alight. It has also been shown to have greater odds ratios, although not statistically significant, for various cancerous and chronic conditions in comparison with other cigarettes. Since bidi is hand-rolled, workers employed in bidi factories are at risk of developing cancerous conditions due to exposure to tobacco dust and flakes. We suggest that anti-smoking campaigns should be directed to the bidi smokers of all South Asian countries. Most bidi smokers are illiterate and malnourished which makes them more vulnerable to smoking-related morbidity and mortality. At the same time, measures should be taken to make bidi less harmful and to produce bidi by machine to reduce exposure-related toxicity among bidi production workers.

Adolescent↗
PubMed2000

Association of thromboangiitis obliterans with cigarette and bidi smoking in Bangladesh: a case-control study.

BACKGROUND: In addition to cigarettes, bidi, made of unprocessed and low-grade tobacco, is being smoked widely in Bangladesh and in other south Asian countries. The cause-and-effect relationship is established between thromboangiitis obliterans (TAO) and smoking. However, type of smoking material(s) most strongly related to TAO is not yet determined. METHODS: We conducted a hospital-based case-control study in Rajshahi, Bangladesh, to examine the relationship of type of smoking materials (cigarette versus bidi) with TAO on 103 pairs of cases and controls matched by age and sex during the period 1995 to 1996. The inclusion criteria for cases were newly diagnosed TAO and current smoker, while those for controls were current smokers admitted to the hospital due to non-cardiovascular diseases. RESULTS: Among the cases 35.0% and 65.0% were cigarette and bidi smokers, while among the controls 69.9% and 30.1%, respectively. Using logistic regression approach, considering cigarette smoking approximately 10 per day as reference, bidi smoking >20 per day (odds ratio [OR] = 34.76, 95% CI: 6.11-197.67) and 11-20 per day (OR = 7.12, 95% CI: 2.35-21.63) had greater risk of TAO after adjusting confounding factors. Respective OR for bidi smoking approximately 10 per day, cigarette smoking 11-20 per day and cigarette smoking >20 per day, were 2.18 (95% CI: 0.64-7.51), 3.81 (95% CI: 1.37-10.57) and 6.88 (95% CI: 1.87-25.30). CONCLUSION: Within the limits inherent to case-control study, our findings suggest that bidi smoking may well play a more important role in causing TAO than cigarettes. It leads to the speculation that unprocessed and low-grade tobacco used for producing bidi might play a more potent role to initiate TAO than cigarettes.

Adult↗
PubMed2000

Prevalence of enterotoxin genes in Aeromonas spp. isolated from children with diarrhea, healthy controls, and the environment.

Aeromonads are causative agents of a number of human infections. Even though aeromonads have been isolated from patients suffering from diarrhea, their etiological role in gastroenteritis is unclear. In spite of a number of virulence factors produced by Aeromonas species, their association with diarrhea has not been clearly linked. Recently, we have characterized a heat-labile cytotonic enterotoxin (Alt), a heat-stable cytotonic enterotoxin (Ast), and a cytotoxic enterotoxin (Act) from a diarrheal isolate of Aeromonas hydrophila. Alt and Ast are novel enterotoxins which are not related to cholera toxin; Act is aerolysin related and has hemolytic, cytotoxic, and enterotoxic activities. We studied the distribution of the alt, ast, and act enterotoxin genes in 115 of 125 aeromonads isolated from 1, 735 children with diarrhea, in all 27 aeromonads isolated from 830 control children (P = 7 x 10(-4) for comparison of rates of isolation of aeromonads from cases versus those from controls), and in 120 randomly selected aeromonads from different components of surface water in Bangladesh. Aeromonas isolates which were positive only for the presence of the alt gene had similar distributions in the three sources; the number of isolates positive only for the presence of the ast gene was significantly higher for the environmental samples than for samples from diarrheal children; and isolates positive only for the presence of the act gene were not found in any of the three sources. Importantly, the number of isolates positive for both the alt and ast genes was significantly higher for diarrheal children than for control children and the environment. Thus, this is the first study to indicate that the products of both the alt and ast genes may synergistically act to induce severe diarrhea. In 26 patients, Aeromonas spp. were isolated as the sole enteropathogen. Analysis of clinical data from 11 of these patients suggested that isolates positive for both the alt and ast genes were associated with watery diarrhea but that isolates positive only for the alt gene were associated with loose stools. Most of the isolates from the three sources could be classified into seven phenospecies and eight hybridization groups. For the first time, Aeromonas eucrenophila was isolated from two children, one with diarrhea and another without diarrhea.

Aeromonas↗