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Biomedical subjects

N Chowdhury

Publications and source records attributed to N Chowdhury.

At least 19 recordsLinked to original sources
PubMed2005

137Cs-uptake into wheat (Triticum vulgare) plants from five representative soils of Bangladesh.

A pot experiment was conducted to study the uptake of 137Cs by wheat grown in five representative soils of Bangladesh having different soil characteristics. Artificial application of 137Cs increased the activity in soils up to 45.9 Bq/kg soil, measured at the end of the harvest of wheat crop. Different plant parts had different ability to accumulate 137Cs. Grains had the least activity and transfer factor, while the highest activity and lowest transfer factor were measured in roots, which restricted translocation of 137Cs to wheat straw. The result showed that the transfer factors (mean value) varied from 0.05 to 0.114 in wheat straw, 0.066-0.133 in roots and 0.011-0.043 in wheat grains. The activity and transfer factor of radioactive cesium in wheat plants were found to be greatly influenced by soil properties, i.e. clay content, K, organic matter, CEC, pH, exchangeable ions, etc. Cation exchange capacity and calcium in soils influenced positively, while clay minerals, exchangeable K and organic matter, negatively affected the 137Cs activity concentrations in wheat plants.

Bangladesh↗
PubMed1998

Pregnancy trends after abortion.

A series of women who aborted their pregnancies at King Khalid University Hospital (KKUH), Riyadh, Saudi Arabia, over a period of 12 months (1 January 1992 to 3 December 1992), were followed up for 6-48 months afterwards to examine their pregnancy trends. Descriptive statistics for data presentation with Kaplan-Meier survivorship function estimates time from abortion to the next pregnancy and Cox proportional hazard regression analysis were used to identify prognostic factors. Eighty-one per cent of the women achieved pregnancy over a 4-year follow-up. The median time to pregnancy was 7.6 months, with a 95% confidence interval of 6.4-10.0 months. Age and nationality were found to be significant prognostic factors related to time to achieve a pregnancy. Furthermore, the outcome of the subsequent pregnancy was found to be statistically related to the number of previous abortions. There is a high chance of fertility after an abortion, with 75.2% of these occurring within the first 12 months of the post-abortion follow-up period and dwindling to only 4.1% by the end of 36 months. Using multivariate regression analysis, only age seemed to be an important determinant factor.

Journal Article↗
PubMed1998

Obstetric outcome in the unbooked mother.

This study aimed at determining the outcome of pregnancy in unbooked mothers with regard to maternal complications and foetal outcome. This retrospective study was based on investigations of medical records of 467 unbooked mothers who presented for delivery at the Obstetrics Unit at King Khalid University Hospital, Riyadh, during the period 1991 and 1992, and 415 booked mothers with regular clinic attendance selected as controls. Data collected from the records included patients' socio-demographic characteristics, past obstetric history, prevalence of pregnancy-related diseases, and data relating to labour, delivery, and foetal outcome. Chi-square test and Fisher's exact test were used for assessing the statistical significance of the association between the various factors which were investigated. The tendency for mothers to be booked was found to be significantly associated with their age, occupation, parity, and gestational age at delivery. Booked and unbooked mothers did not differ significantly in relation to the mode of delivery and foetal outcome, although the prevalence of previous complications of pregnancy was generally lower among unbooked mothers. There was no statistically significant association between the absence of antenatal care and outcome of pregnancies, unbooked mothers had a higher proportion of MICU admissions and dead babies compared with the controls. Educating the community about the benefits of receiving regular antenatal care, even if at primary care level, may be of great importance in improving the pregnancy outcome.

Adolescent↗
PubMed1997

An appraisal of the appropriateness of the indications for hysterectomy.

Over a five-year period, 197 hysterectomies were performed at King Khalid University Hospital (KKUH). Indications for the procedures vary from menstrual disorders and symptomatic fibroids to ovarian malignancy. The most common indication was found to be menorrhagia. Among multiple pre-operative indications, only the first listed major indication for hysterectomy was chosen. There were 145 abdominal and 52 vaginal hysterectomies and all were elective gynaecological procedures, majority of which were performed on women in their fourth and fifth decades of life. Verification of pre-operative diagnosis, when correlated with pathological findings, showed that some of the indications for the procedure deserve a more critical reappraisal. Since hysterectomy carries substantial economic and medical consequences, indications for undertaking the procedure deserve more careful scrutiny given the surgical and nonsurgical options that are currently available. There may be a need, therefore, to assess the appropriateness or otherwise of the use of hysterectomy in many of the patients in future.

Journal Article↗
PubMed1997

Risk of retained placenta: multivariate approach.

BACKGROUND: To identify important covariates related to retained placenta using logistic regression analysis. METHODS: The study was carried out in the King Khalid University Hospital, Saudi Arabia, and involved 114 women who had retained placenta, and 116 women with normal deliveries. Chi-square test and logistic regression analysis were used for analysis of data. Adequacy of predictor variables was examined using indices of sensitivity and specificity and plots of probability histograms for prediction of retained placenta among patients and controls. RESULTS: Logistic regression analysis highlighted multiparity, induced labor, small placenta, and large amount of blood loss to be significantly associated with retained placenta. In addition, high pregnancy number, previous injury to uterus, and pre-term labor related significantly to retained placenta. Predictor variables had sensitivity of 65.5% and 87.9% specificity and achieved 77% overall correct classification. CONCLUSIONS: These findings could be used to develop a predictive procedure for identifying high-risk cases of retained placenta.

Case-Control Studies↗
PubMed1996

Sequelae of repeat cesarean sections.

OBJECTIVES: To study and analyze the factors related to repeat cesarean section and to highlight the problems that may be associated with it. METHODS: The study was carried out in the Department of Obstetrics and Gynaecology, King Khalid University Hospital, Riyadh, Saudi Arabia, and involved 395 patients who had had two or more previous cesarean sections prior to the current pregnancy. Various factors which may be associated with repeat cesarean sections, as well as the outcome of the operations, were assessed and analyzed. The chi2-test and other analyses were used to examine the association between the number of cesarean sections and the various variables. RESULTS: Four or more previous cesarean sections was significantly associated with dense adhesions. On the other hand, height, parity, antenatal clinic attendance, postoperative complications, fetal weight and fetal outcome had no significant effect on, nor influenced, the multiplicity of cesarean sections. CONCLUSION: No specific risk is associated with repeat cesarean sections that is not normally associated with single cesarean sections.

Adult↗
PubMed1996

Obstetric outcome in uncomplicated prolonged pregnancy.

OBJECTIVE: To study and compare the obstetric outcome in term pregnancies and uncomplicated prolonged pregnancies. METHODS: The study was a retrospective review of 596 cases. The case notes of 286 patients with uncomplicated prolonged pregnancies (> or = 42 weeks) and 310 patients with normal term pregnancies (37 to < 42 weeks) were analyzed. The Gold Stat package was used for statistical coding and analysis. RESULTS: There was no fetal morbidity or mortality among the two groups. However, the number of previous abortions were significantly higher in prolonged pregnancies compared with term pregnancies. Similarly, fetal and placental weights, labor induction and operative delivery rates were significantly higher in prolonged pregnancies. However, there were no significant differences between the patients who were induced and those who had spontaneous labor among the prolonged pregnancies. CONCLUSIONS: There is no doubt that prolonged pregnancy may be associated with certain risks factors. However, there is no outcome variable to justify whether or not to induce those pregnancies which are prolonged.

Adolescent↗
PubMed1996

Neuropeptides induce release of nitric oxide from human dermal microvascular endothelial cells.

Nitric oxide is a potent mediator of endothelium-dependent vasodilation, the synthesis of which is catalyzed by the constitutively expressed enzyme endothelial nitric oxide synthase. In this study we have investigated whether human dermal microvascular endothelial cells express endothelial oxide synthase and whether the vasodilator neuropeptides, calcitonin gene-related peptide and substance P, stimulate the release of nitric oxide from these cells. Endothelial nitric oxide synthase was identified by immunohistochemistry in the blood vessels in both the papillary and deep dermis of normal skin, and also in monolayers of human dermal microvascular extracts prepared from both the dermis of normal human skin and human dermal microvascular endothelial cells, a 135-kDa band corresponding to endothelial nitric oxide synthase was identified. Nitric oxide was released from unstimulated human dermal microvascular endothelial cells as assessed by inhibition of platelet aggregation and nitrate formation. Endothelial cell-mediated inhibition of platelet aggregation was blocked by hemoglobin. Calcitonin gene-related peptide, (100 pM to 100 nM) directly inhibited platelet aggregation, and this direct effect was not modulated by microvascular endothelial cells. Substance P (10 nM to 1 muM) and calcitonin gene-related peptide (100 pM to 10 nM) significantly (p<0.05) increased nitrite formation, and this increase was blocked by the competitive nitric oxide synthase antagonist, NG-monomethyl-L-arginine. These results demonstrate that endothelial nitric oxide synthase is expressed in the microvascular endothelium of normal human skin and that human dermal microvascular endothelial cells release nitric oxide constitutively and in response to vasodilator neuropeptides.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

Accuracy of hysterosalpingography and laparoscopic hydrotubation in diagnosis of tubal patency.

OBJECTIVE: To compare the diagnostic accuracy of two methods of assessment of tubal patency, viz, hysterosalpingography (HSG) and laparoscopic hydrotubation. DESIGN: One hundred four infertile women who were investigated with both HSG and laparoscopy in King Khalid University Hospital were selected for the study. Complete history of factors that may predispose to tubal occlusion was obtained. Patients with problems of ovulatory failure or poor semen analysis that may contribute to their infertility were excluded. RESULTS: The overall agreement between the two methods was 62.5%. However, the diagnostic accuracy of the two methods differed significantly. CONCLUSION: It would appear that laparoscopic hydrotubation, despite its invasive nature, had an edge in diagnostic accuracy when compared with HSG. It would be advantageous to subject patients in whom HSG has shown tubal blockage to laparoscopy or any of the newer techniques of hysteroscopy or sonographic hydrotubation.

Adult↗
PubMed1995

Reproductive potential after an ectopic pregnancy.

OBJECTIVE: To measure statistically how soon pregnancy can occur after an ectopic pregnancy (EP) so as to determine the cumulative pregnancy rate and the risk factors involved in nonpregnancy. DESIGN: The risk of not getting pregnant after an EP (survivorship) was estimated for 120 patients followed up for up to 60 months using the actuarial life-table technique. The risk factors involved in nonpregnancy, abortions, or live births were analyzed, using Cox regression models. SETTING: King Khalid University Hospital, Riyadh, Saudi Arabia. RESULTS: There were 68 pregnancies over the study period, with a conception rate of 56.7%. Using the actuarial life table, the cumulative probability of not achieving pregnancy in a patient decreased sharply during the first 12 months, followed by a gradual decrease up to 48 months. The Cox regression analysis showed a correlation between pregnancy and two variables, namely, age and history of prior EP. The chances of a pregnancy resulting in abortion or live birth also correlated with the presence of prior infertility, pelvic inflammatory disease (PID), or postoperative complications. CONCLUSION: Age and prior EP are important determinants in pregnancy rates after an EP. Similarly, history of PID, infertility, and postoperative complications are important risk factors in whether the pregnancy goes to term or ends in abortion.

Abortion, Spontaneous↗
PubMed1995

Infection resistance of surface modified catheters with either short-lived or prolonged activity.

It has been suggested that the invasion of microbes into the catheter tract occurs mainly at the time of catheter insertion. To investigate whether the presence of an antimicrobial environment during the initial period after insertion is sufficient to reduce the risk of subsequent catheter colonization and infection, we evaluated the use of benzalkonium chloride-heparin bonded (BZK-hep) central venous catheters, which exhibit short-lived surface antimicrobial activity, using a rat subcutaneous model. Bacterial adherence on these catheters was determined, seven days after challenging the insertion site with 10(6) cfu of Staphylococcus aureus. A chlorhexidine-silver sulphadiazine impregnated catheter (Arrowg+ard), with longer lasting surface antimicrobial activity, and a hydrophilic coated catheter ('Hydrocath'), were evaluated simultaneously for comparison. Unlike Arrowg+ard antiseptic catheters, BZK-hep 'Hydrocath' and control catheters had significant bacterial adherence on their surface. Arrowg+ard catheters were colonized in 19% of the animals compared with 100% in all the other groups (P < 0.05; mean cfu cm-2: control = 1.3 x 10(6), BZK-hep = 4.3 x 10(5), Hydrocath = 2 x 10(5), Arrowg+ard = 71). Our results indicate that catheters with short-lived surface antimicrobial activity are unlikely to provide long-term protection against catheter-related infection. The efficacy of Arrowg+ard catheters may be due to the initial high rate of kill and prolonged antimicrobial activity.

Animals↗
PubMed1995

Distribution of cobalt in parasitic helminths.

The distribution of cobalt in parasitic helminths belonging to the trematodes, cestodes or nematodes was determined by the use of an atomic absorption spectrophotometer. The results of these analyses have demonstrated that growing trematodes (smaller forms) with active oogenesis and spermatogenesis contained more cobalt that older forms (large or very old adults) with empty uteri and large lobulated testes. In cestodes the neck region of cysticerci and immature proglottids of adults showed more cobalt than the cyst portion of cysticerci and hydatid or mature and gravid proglottids of worms. Similarly, the youngest endogenous daughter cysts of Echinococcus granulosus showed more cobalt in their walls than those of larger forms. The element was found more concentrated in nematode eggs than in adult females, irrespective of species of host.

Animals↗
PubMed1994

Induction of myocardial nitric oxide synthase by cardiac allograft rejection.

Cardiac transplantation, effective therapy for end-stage heart failure, is frequently complicated by allograft rejection, the mechanisms of which remain incompletely understood. Nitric oxide (NO), a vasodilator which is cytotoxic and negatively inotropic, can be produced in large amounts by an inducible NO synthase (iNOS) in response to cytokines. To investigate whether iNOS is induced during cardiac allograft rejection, hearts from Lewis or Wistar-Furth rats were transplanted into Lewis recipients. At day 5, allogeneic grafts manifested reduced contractility and histologic evidence of rejection (inflammatory infiltrate, edema, necrosis of myocytes). The mRNA for iNOS and iNOS protein were detected in ventricular homogenates and in isolated cardiac myocytes from rejecting allogeneic grafts but not in tissue and myocytes from syngeneic control grafts. Immunocytochemistry showed increased iNOS staining in infiltrating macrophages and in microvascular endothelial cells and cardiac muscle fibers and also in isolated purified cardiac myocytes from the rejecting allografts. Using a myocardial cytosolic iNOS preparation, nitrite formation from L-arginine and [3H] citrulline formation from [3H]L-arginine were increased significantly in the rejecting allogeneic grafts (P < 0.01). Myocardial cyclic GMP was also increased significantly (P < 0.05). The data indicate myocardial iNOS mRNA, protein and enzyme activity are induced in infiltrating macrophages and cardiac myocytes of the rejecting allogeneic grafts. Synthesis of NO by iNOS may contribute to myocyte necrosis and ventricular failure during cardiac allograft rejection.

Amino Acid Oxidoreductases↗
PubMed1993

Ovarian pregnancy.

Ovarian ectopic pregnancy occurs very rarely; the reported incidence is only 1:7000-40,000 deliveries, despite various reports in recent years. We present four cases of primary ovarian pregnancy which were managed in the King Khalid University Hospital (KKUH) over a 5-year period representing a prevalence rate of 19.9 per 100,000 deliveries. All four cases complied with the four criteria of Spiegelberg. None of the patients were known to have used an intrauterine contraceptive device which had been suggested as the cause of ovarian pregnancies in several studies. Fertility after surgery in these cases was unaffected.

Adult↗
PubMed1993

Distribution of some elements in hydatid cysts of Echinococcus granulosus from buffalo (Bubalus bubalis).

Distribution of some elements during development of endogenous daughter (hydatid) cysts of Echinococcus granulosus of buffalo origin was determined by atomic absorption spectrophotometry. These analyses showed that the distribution of copper and cobalt was highest in the smallest cysts. These elements gradually decreased in the cysts as they enlarged. The distribution of zinc, iron and manganese was very high in the smallest cysts in comparison to copper and cobalt, but these three elements decreased greatly in larger cysts. Iron and manganese were the only two elements found in very high concentrations in "thin-walled" cysts. Like all other elements both calcium and magnesium decreased as the cysts increased in size. In the thin-walled cysts magnesium increased by four times initially and this was followed by a two-fold "influx" of calcium in the "white-spots" in the above cysts. The significance of these findings is discussed in relation to earlier works.

Animals↗
PubMed1993

Three consecutive recurrent ectopic pregnancies.

A case of three consecutive repeated ectopic pregnancies is presented in a 36-year-old woman who was being managed for infertility. The first two ectopic pregnancies occurred in the right fallopian tube, and both were treated conservatively. All three ectopic pregnancies were confirmed histopathologically. The aetiology, symptoms and management of the case are discussed, and the literature is reviewed.

Adult↗