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Biomedical subjects

S Islam

Publications and source records attributed to S Islam.

At least 73 records · Page 4Linked to original sources
PubMed1997

Noninvasive assessment of gastric acid secretion in man. Application of electrical impedance tomography (EIT).

Electrical impedance tomography (EIT) is a tubeless technique that generates tomographic images of gastric resistivity. We investigated the application of EIT to measure gastric acid secretion. Nineteen normal subjects underwent a standard intubation test. Basal acid output (BAO) and stimulated acid output (SAO) (millimoles per hour) were measured before and after pentagastrin, respectively. On a different day, EIT was performed before (basal) and after pentagastrin (stimulated). The changes in impedance over time were measured and the area under the curve (AUC) was calculated. Both the tests were repeated in 13 subjects after omeprazole treatment. As in the intubation test, there was the expected increase in AUC value after pentagastrin (basal vs stimulated; 1.2 +/- 2.8 vs 731 +/- 297, P < 0.0001). A significant fall in acid output and AUC following omeprazole pretreatment was observed (without vs with omeprazole; 20.5 +/- 5.7 vs 0.03 +/- 0.06, P < 0.0001 for intubation test and 731 +/- 297 vs 44 +/- 172, P < 0.0001 for EIT). There was a significant correlation between SAO and the delta AUC with (r = 0.65 P < 0.001) or without (r = 0.95, P < 0.001) omeprazole and in all the experiments (r = 0.87, P < 0.001). This study demonstrates the predictable change of gastric impedance and may be useful as a noninvasive test for measuring gastric acid secretion.

Adolescent↗
PubMed1997

Aziridinyl steroid-induced lesions in DNA and apoptosis in promyelocytic leukemia cells.

Variety of synthetic steroids are reported to be mutagenic as well as carcinogenic. The mutagenic and carcinogenic nature of these compounds have been related to their potential of being reactive to genetic material and production of reactive oxygen species. Here we have analyzed the action of aziridinyl steroid on calf thymus DNA and human promyelocytic leukemia cell line HL-60 under in vitro conditions. Calf thymus DNA when treated with various doses of aziridinyl steroid induced a high degree of stand separation and sensitivity/susceptibility to S1 nuclease hydrolysis. The treatment also induced an increasing number of strand breaks per molecule of DNA as determined by alkaline unwinding assay. Relatively higher doses of steroid, however, displayed a reduced susceptibility to S1 nuclease hydrolysis and did not increase the number of strand breaks in DNA. Moreover, the high dose treatments result increased melting temperature and an enhanced rate of reanealing after thermal denaturation, indicating that interstrand crosslinks are induced at higher doses of steroid treatment. Moreover, steroid treatment caused cell death in human promyelocytic leukemia cell line HL-60 and induced DNA degradation, characteristic of apoptosis. The test steroid has the ability to produce reactive oxygen intermediates (ROI) as determined by chemical methods. Incorporation of oxygen radical scavengers into the system blocked the damaging effect of steroid in calf thymus DNA and HL-60 cells. These observations strongly suggest that aziridinyl steroid, a pharmaceutical, damages mammalian DNA and induces apoptosis by the production of ROI in the test system.

Animals↗
PubMed1997

Prevalence of Helicobacter pylori in asymptomatic population--a pilot serological study in Bangladesh.

Epidemiological reports reveal that H. pylori is distributed among all population in the world. The present cross-sectional study was undertaken to see the H. pylori seroprevalence rates among the asymptomatic adults, as yet reportedly no such data available in Bangladesh. Serum samples were collected from 181 consecutive subjects who attended at the health check-up centre of Bangladesh Institute of Diabeties, Endocrine and Metabolic Disorders (BIRDEM), Dhaka, during the period of August to November 1995 for medical check up. The mean age of these subjects was 30.33 years (range 20-44 yrs). Incidentally all were male and belonged to average socioeconomic class. H. pylori specific IgG antibody level was assayed by an enzyme immunoassay kit ElAgen (Clone system). Among the 181 subjects, 166 (92%) had H. pylori specific antibodies and 15 (8%) were seronegative. No significant difference (p < 0.90) in seroprevalence rates was observed among different age groups. However, the results of higher seroprevalence rates of H. pylori infection in these asymptomatic adult population of Bangladesh are consistent with that of Africa and India.

Adult↗
PubMed1997

Shelf-life of pre-cooked rice oral rehydration salt packets.

The shelf-life of pre-cooked rice oral rehydration salts (ORS) at the household level was studied in urban Dhaka. To prepare the packets, cooked rice was dried and ground to fine powder and the salt ingredients were mixed according to the World Health Organization formulation. For each half liter packet, 10 g glucose was replaced by 25 g of instant cooked rice powder. The packets were kept in different environments for three months among 30 households of varying socioeconomic status. At monthly intervals, two packets from each family were collected for laboratory tests. Physical characteristics of ORS such as color and dispersibility remained the same throughout the three month study period. However, in the third month flavor changed slightly. The electrolyte concentration of the prepared solution remained the same at the end of the first, second and third months. However, progressive but minimal increase in moisture content of the packets was noted over the allotted time period. This increase in moisture was less when the mixture was packed in double thin layer polythene bags as opposed to the single layer bags. In conclusion, the shelf-life of pre-cooked rice ORS remains stable at least up to three months when stored at the household level. Therefore, pre-cooked rice ORS can be kept at households for future use in the event of diarrheal episodes.

Diarrhea↗
PubMed1996

Enhanced fidelity of 3TC-selected mutant HIV-1 reverse transcriptase.

Monotherapy with (-)2',3'-dideoxy-3'-thiacytidine (3TC) leads to the appearance of a drug-resistant variant of human immunodeficiency virus-type 1 (HIV-1) with the methionine-184 --> valine (M184V) substitution in the reverse transcriptase (RT). Despite resulting drug resistance, treatment for more than 48 weeks is associated with a lower plasma viral burden than that at baseline. Studies to investigate this apparent contradiction revealed the following. (i) Titers of HIV-neutralizing antibodies remained stable in 3TC-treated individuals in contrast to rapid declines in those treated with azidothymidine (AZT). (ii) Unlike wild-type HIV, growth of M184V HIV in cell culture in the presence of d4T, AZT, Nevirapine, Delavirdine, or Saquinavir did not select for variants displaying drug resistance. (iii) There was an increase in fidelity of nucleotide insertion by the M184V mutant compared with wild-type enzyme.

Antiviral Agents↗
PubMed1996

Morphological study of thymus stromal cells (TEL-2 cell) which play a role in the elimination of double positive immature thymocytes by phagocytosis.

BACKGROUND: The process of the selective elimination of immature double positive thymocytes, during culture with TEL-2 cells (an epithelial cell line from the thymus stroma), is initiated by the contact between thymocytes and TEL-2 cells (Nakashima et al. 1990 Eur. J. Immunol., 20: 47-53; Hirata et al. 1991 Anat. Rec., 230: 524-530). METHODS: Our approach was to follow the process of thymocyte internalization as a sequelae of this interaction with scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron microscopic cytochemistry for the hydrolytic enzyme acid phosphatase (Ac Pase). RESULTS: With SEM, numerous thymocytes lay underneath the TEL-2 cells. An enhanced activity of the TEL-2 cell membrane, consisting of several thin thread-like projections either with or without an expanded termination, was involved with contacting the thymocytes. With TEM, close appositions were noted either at adjacent segments of the cellular membrane or between thick plump local protrusions of the plasma membrane. Blunt pseudopodia and deep invaginations on indented portions of the TEL-2 surface engulfed one or more thymocytes. With Ac Pase histochemistry: 1) the incorporation of thymocytes into a phagosome was indicated by the Ac Pase negative thymocytes enclosed in a membrane beneath the protuberance of a TEL-2 cell surface without fusion to the TEL-2 lysosomes; 2) most of these thymocytes were morphologically intact, whereas the rest were already damaged, having changes similar to apoptosis; and 3) a few Ac Pase positive dense bodies of the TEL-2 cell, mostly with the morphology of secondary lysosomes, fused with the thymocyte-enclosing membrane after which the digestion of several thymocytes proceeded. CONCLUSIONS: With the prominent activity of the plasma membrane involving the initial attachment and subsequent phagocytosis, a murine thymic epithelial cell line TEL-2 plays a demonstrating role in the mechanism of the elimination of double positive thymocytes.

Acid Phosphatase↗
PubMed1996

Expression of N-cadherin by human squamous carcinoma cells induces a scattered fibroblastic phenotype with disrupted cell-cell adhesion.

E-cadherin is a transmembrane glycoprotein that mediates calcium-dependent, homotypic cell-cell adhesion and plays an important role in maintaining the normal phenotype of epithelial cells. Disruption of E-cadherin activity in epithelial cells correlates with formation of metastatic tumors. Decreased adhesive function may be implemented in a number of ways including: (a) decreased expression of E-cadherin; (b) mutations in the gene encoding E-cadherin; or (c) mutations in the genes that encode the catenins, proteins that link the cadherins to the cytoskeleton and are essential for cadherin mediated cell-cell adhesion. In this study, we explored the possibility that inappropriate expression of a nonepithelial cadherin by an epithelial cell might also result in disruption of cell-cell adhesion. We showed that a squamous cell carcinoma-derived cell line expressed N-cadherin and displayed a scattered fibroblastic phenotype along with decreased expression of E- and P-cadherin. Transfection of this cell line with antisense N-cadherin resulted in reversion to a normal-appearing squamous epithelial cell with increased E- and P-cadherin expression. In addition, transfection of a normal-appearing squamous epithelial cell line with N-cadherin resulted in downregulation of both E- and P-cadherin and a scattered fibroblastic phenotype. In all cases, the levels of expression of N-cadherin and E-cadherin were inversely related to one another. In addition, we showed that some squamous cell carcinomas expressed N-cadherin in situ and those tumors expressing N-cadherin were invasive. These studies led us to propose a novel mechanism for tumorigenesis in squamous epithelial cells; i.e., inadvertent expression of a nonepithelial cadherin.

Cadherins↗
PubMed1996

Body-composition measurement in 9-11-y-old children by dual-energy X-ray absorptiometry, skinfold-thickness measurements, and bioimpedance analysis.

We compared, in 9-11-y-old children (n=43), three measures of body composition: dual-energy X-ray absorptiometry (DXA), skinfold thickness, and bioimpedance analysis (BIA). The intraclass correlation coefficient (ICC), Bland-Altman procedure, and Spearman rank correlation were used to determine test-retest reliabilities of the three methods and to compare methods. For DXA measurements, the rank correlation between fat-free soft tissue and fat-free mass (FFM) was > 0.99, indicating that bone mineral content did not provide independent information. Thus, subsequent analyses used the two-compartment model (ie, fat mass and FFM) for all three techniques, focusing especially on values for percentage of fat. The test-retest reliabilities for all methods were high (ICCs > 0.994 and no significant differences between trials 1 and 2). The range of individual differences from trial 1 to trial 2 and Bland-Altman limits of agreement suggested that the reliability was greatest for DXA, followed by BIA and skinfold-thickness measurement. The percentage of fat values for the three methods were highly intercorrelated (all Spearman r values > 0.83). However, there was a systematic tendency (P < 0.01) for DXA values (mean: 23.98) to be higher than those derived from skinfold-thickness measurements (mean: 21.05) and BIA (mean: 21.52). The variance in percentage of fat values for BIA was significantly smaller than that for the other two techniques. These findings, along with rather large limits of agreement derived from the Bland-Altman procedure, suggest that the methods should not be used interchangeably.

Absorptiometry, Photon↗
PubMed1996

Physical training, lifestyle education, and coronary risk factors in obese girls.

The effects of supervised physical training (PT) and lifestyle education (LSE) on risk factors for coronary artery disease and non-insulin-dependent diabetes mellitus were compared in obese 7- to 11-yr-old black girls. The subjects were divided into two groups. The PT group (N = 12) completed a 5-d.wk-1, 10-wk, aerobic training program; and the LSE group participated in weekly lifestyle discussions to improve exercise and eating habits. The PT group showed a significant increase in aerobic fitness (P < 0.05) and decrease in percent body fat (P < 0.05), while the LSE group declined significantly more in dietary energy and percent of energy from fat (P < 0.05). Fasting insulin did not change significantly. The LSE group declined significantly more than the PT group in glucose (P < 0.05), and glycohemoglobin declined from baseline in both groups (P < 0.05). Lipid changes were similar in the two groups: total cholesterol/high density lipoprotein cholesterol (P < 0.01) and triglycerides (P < 0.05) declined, the low density lipoprotein (LDL)/apoproteinB ratio increased (which indicates a decrease in small dense LDL) (P < 0.05) and lipoprotein(a) increased (P < 0.05). Thus, the interventions were similarly effective in improving some diabetogenic and atherogenic factors, perhaps through different pathways; i.e., the PT improved fitness and fatness, while the LSE improved diet. Exercise and diet-induced changes in lipoprotein(a) require further investigation.

Child↗
PubMed1996

Parasuicide in Pakistan: experience at a university hospital.

There have been few reports of parasuicide from Pakistan, where the act is considered to be a criminal offence and the Islamic religion strongly disapproves of it. In order to address the problem, a retrospective case report analysis of all index cases of parasuicide presenting over a period of 3.5 years to a university hospital in Karachi, Pakistan, was undertaken. Our results showed that most of the subjects were young adults, with married women representing the single largest group. Self-poisoning with medication was the most common method, and benzodiazepines the most frequently used drug. Interpersonal conflict with the opposite sex was the most common precipitating cause. In Pakistani culture, marriage appears to be a significant source of stress for women. Reports based on official police records do not reflect the true picture of the problem in Pakistan.

Adolescent↗
PubMed1996

The relationship of behavioral cues to assaultive behavior.

The purpose of this 2-year, case control study was to determine whether differentiation between assaultive and nonassaultive patients can be made based on behavioral assessments and/or sociodemographic variables. For each assault incident, the chart of the patient who assaulted and a randomly chosen patient who did not assault on that day were reviewed (N = 72 subjects or 26 pairs). Various scales were used to evaluate the subjects retrospectively (the day prior to the assault), and patients who assaulted staff were interviewed when possible. An analysis found no differences between patients who assaulted and controls on sociodemographic variables. Those who assaulted had significantly more prior assaults (p = .04) and more difficulty verbalizing angry feelings appropriately on their units (p < .01). Prior to the assault, assaultive patients were more verbally hostile (p = .037) and showed more increased motor activity (p = .001) than controls.

Cues↗
PubMed1996

A prospective randomized study of end points of resuscitation after major trauma: global oxygen transport indices versus organ-specific gastric mucosal pH.

BACKGROUND: Gastric tonometry, as a method of organ-specific monitoring of the status of the splanchnic circulation, has demonstrated prognostic and therapeutic implications in critically ill patients. The experience with this method in patients with trauma has been limited. STUDY DESIGN: Fifty-seven patients were prospectively randomized into two groups: group 1, n = 30, normalization and maintenance of gastric mucosal pH (pHi) at or above 7.3 and group 2, n = 27, maintenance of oxygen delivery index of 600 or an oxygen consumption index of greater than 150. The groups had statistically similar injury severity scores, lactate levels, and base deficits. RESULTS: Of the 44 patients with pHi greater than 7.3 at 24 hours, three (6.8 percent) died of multiple organ dysfunction syndrome as compared with seven (53.9 percent) of 13 in whom pHi was not optimized, p = 0.006. Optimization times for oxygen delivery index, oxygen consumption index, lactate levels, and base excess were similar between survivors and nonsurvivors. The time for pHi optimization was significantly longer in nonsurvivors. Multiple organ dysfunction syndrome points were significantly higher in patients who did not have pHi optimized within 24 hours (6.08 compared with 2.5, p = 0.03). Optimization time for pHi was predictive of mortality on multiple regression. Persistently low pHi was frequently associated with systemic or intra-abdominal complications. It was the first finding in all the nonsurvivors at least 48 to 72 hours before death. CONCLUSIONS: Gastric mucosal pH may be an important marker to assess the adequacy of resuscitation. Monitoring of pHi may provide early warning for systemic complications in the postresuscitation period.

Adolescent↗
PubMed1996

Acute cholecystitis resulting from hemobilia after tru-cut biopsy: a case report and brief review of the literature.

Acute cholecystitis following hemobilia is very rare, with only five cases reported in the literature. A case report of a 22-year-old woman who underwent a liver biopsy for staging of Hodgkin's lymphoma and developed cholecystitis due to hemobilia is presented. The incidence of hemobilia has increased with the advent of more invasive hepatobiliary procedures, but the mortality has been decreasing due to better recognition and therapy. Acute cholecystitis associated with hemobilia is very rare, but will be seen with increasing frequency; and a high index of suspicion needs to be maintained to ensure timely diagnosis and treatment.

Acute Disease↗
PubMed1996

Intestinal transport of water, sodium & glucose from an electrolyte solution with & without bicarbonate.

In this study we have evaluated the role of bicarbonate on water and sodium transport in normal and secreting ilea of rabbits as controversy exists regarding the inclusion of bicarbonate in oral rehydration solution (ORS). In anaesthetized rabbits 10 cm closed ileal loops were constructed and filled with 5 ml of an electrolyte solution with and without bicarbonate, which contained polyethylene glycol (PEG; mol wt 4,000) as a non-absorbable marker. The fluid was withdrawn after an hour and analyzed for PEG, sodium and glucose. Similar studies were carried out in loops one hour after exposure to 1 microgram/ml of purified cholera toxin. Body temperature was maintained at 37 degrees C during the experiment by using a lamp. The mean +/- SE of water and sodium absorption, with bicarbonate versus without bicarbonate, was -1.4 +/- 0.1 vs -1.1 +/- 0.3 ml/h/10 cm, and -340.8 +/- 23.0 vs -308.4 +/- 35.6 mM/h/10 cm, respectively from secreting rabbit ilea. A similar effect was observed in normal ilea. It is concluded that bicarbonate containing electrolyte solution has no additional promoting effect on water and sodium absorption in normal or secreting ilea of rabbits.

Animals↗
PubMed1995

Effects of antisense oligonucleotides to the cardiac Na+/Ca2+ exchanger on cultured cardiac myocytes.

Antisense oligodeoxynucleotides based on the sequence of the cardiac Na+/Ca2+ exchanger were used to study the effects of decreasing expression of this protein on Na(+)-dependent Ca2+ uptake activity and on the spontaneous beating rate of cultured rat cardiac myocytes. Antisense oligos reduced Na+/Ca2+ exchanger activity of myocytes approximately 30-40%, compared to sense-treated or untreated controls. Antisense treatment also increased the spontaneous beating rate of myocardial cells from an average rate of 40 beats to 69 beats per minute, compared to sense-treated or untreated controls. These results indicate that reduced expression of the Na+/Ca2+ exchanger significantly alters intracellular Ca2+ regulation leading to an enhanced spontaneous beating rate and, presumably, a shortened duration of the cardiac cycle in developing myocytes.

Animals↗