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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

Acetate causes endothelium-independent increases in cyclic AMP in rat caudal artery.

The mechanism of the vasorelaxant action of acetate is unknown. Because cyclic nucleotides have been linked to vasorelaxation in vascular smooth muscle, we studied the effects of acetate on tissue adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) levels in rat caudal artery. Acetate (4 mM) induced an increase in tissue cAMP levels (control: 5.1 +/- 0.67, acetate: 7.1 +/- 0.97 pmol/mg protein, P less than 0.05), with the increase noted as early as 15-30 s after acetate exposure, and peaking at 60 s. The time course of the cAMP response was compatible with the vasorelaxant effect of acetate against an arginine vasopressin (AVP, 2 X 10(-9) M) contraction. Both the increase in cAMP and the vasorelaxant effect were completely blocked by 10(-3) M 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). Acetate increased cAMP levels in 3-isobutyl-1-methylxanthine (IBMX)-treated tissue with an effective concentration producing 50% of the maximum response (EC50) of 1.5 mM, similar to the relaxant EC50 (without IBMX) of 2.2 mM against an AVP contraction. In other experiments, the effect of acetate on cAMP was shown to be independent of endothelium. In contrast, acetate had no effect on tissue cGMP levels, whether the endothelium was present or absent. The results suggest that acetate causes an increase in tissue cAMP levels that is not dependent on presence of a functioning endothelium. The changes in cAMP may be contributory to the vasorelaxant effect of acetate in the caudal artery.

1-Methyl-3-isobutylxanthine

Comparative study of the effect of beta-blockers with different pharmacological properties on cholesteryl ester formation in mouse peritoneal macrophages.

The effect of three beta-blockers: non-selective (propranolol), beta 1-selective (metoprolol), and with intrinsic sympathomimetic activity (pindolol), was investigated on 14C-oleic acid incorporation into cholesteryl esters in mouse peritoneal macrophages. Incorporation of 14C-oleic acid into cholesteryl esters was reduced about 10-fold by propranolol at 10(-4) M while incorporation into triacylglycerols was only 30% decreased at the same concentration. Metoprolol and pindolol had no significant effect on 14C-oleic incorporation into cholesteryl esters or triacylglycerols. Finally, propranolol inhibited the acyl-coenzyme A: cholesterol-O-acyltransferase activity, measured in vitro on macrophages homogenates, while the other studied beta-blockers were ineffective. These results suggest that propranolol could antagonize cholesteryl ester accumulation by macrophages, one of the main processes involved in atherogenesis.

Adrenergic beta-Antagonists

Impact of massive doses of vitamin A on nutritional blindness in Bangladesh.

Impact of 6-monthly massive dosings of preschool-age children with oral vitamin A (VAC: 200,000 IU of oil soluble retinyl palmitate with 40 IU vitamin E) was evaluated in Bangladesh. In 100 sites, 11,889 households were visited and eyes of 22,335 children aged 3-71 mo were examined. About half the rural target population and less than 20% urban slum population were being reached. Risk of night blindness was halved for children reportedly given VAC, although 2.5% of the reportedly protected population were still night blind. There was no significant reduction in prevalence of Bitot's spot. Risk of corneal ulcers or keratomalacia (X3A/B) was 2.7 times higher in children not given VAC. Based on reported coverage, efficacy of protection against potentially blinding corneal lesions was 63%. For maximum impact on eye lesions, massive dosing with vitamin A at ideally less than 6-monthly intervals needs to be combined with other nutrition and health interventions.

Bangladesh

[Association of autoimmune chronic active hepatitis and acquired erythroblastopenia cured by cyclophosphamide].

To the best of our knowledge this is the reported first case of the successive occurrence in the same patient of chronic active hepatitis and acquired pure red cell aplasia, both probably of autoimmune origin. The diagnosis of autoimmune hepatitis was based on the presence of characteristic lesions at the examination of the liver biopsy specimen, high titer of anti-smooth muscle antibodies in the serum, and remission obtained by steroid therapy. Erythroid aplasia, which appeared during the course of this treatment, was revealed by a regenerative anemia (4.4 g Hb/100 ml) and proved by bone marrow aspiration and biopsy. In vitro bone marrow culture was normal, suggesting the in vivo presence of an inhibitor of erythroblastic differentiation. Red cell aplasia was cured by cyclophosphamide (100 mg/day during 56 days). No recurrence was noted until the death of the patient, which occurred one year later, due to hepatic cholangiocarcinoma. Action of cyclophosphamide on the pure red cell aplasia suggested the immune origin of this disease. The liver and the bone marrow erythroid lineage have probably been the successive targets of immunologic dyscrasia.

Autoimmune Diseases

Fasting serum bile acid level in cirrhosis. A semi-quantitative index of hepatic function.

We examined the roles of the factors which influence bile acid levels in order to define to what extent fasting serum total bile acid (FSTBA) level might reflect hepatic function and/or anatomy of the portal circulation in patients with cirrhosis. In a first group of 13 patients having mild to moderately advanced cirrhosis we determined the apparent oral clearance (CLo) of chenodeoxycholic acid (764 mumol) and their FSTBA levels. In a second group of 15 similar patients we measured FSTBA levels and by hepatic vein catheterization the intrinsic clearance (CLi) of ICG as well as total hepatic blood flow (Q). We found a significant inverse log-log relationship (r = 0.752, P less than 0.01) between the FSTBA and the CLo on the one hand and significant inverse log-log relationship (r = 0.707, P less than 0.01) between the FSTBA and CLi on the other hand. Q was not found to bear any significant relation to FSTBA (r = 0.120, P greater than 0.1). To conclude, in view of the observed relationship between CLi and CLo vs FSTBA, the latter might serve as a simple non-invasive semiquantitative index of hepatic function and/or anatomy of portal circulation in cirrhosis.

Adult

[Survival of patients in acute renal failure: effect of nutrition and its associated complications].

A retrospective study of 150 patients with acute renal failure (ARF) was conducted to assess the influence of both protein and caloric intake and non-renal complications on the prognosis, as well as the predictive value of plasma protein levels. The majority of ARF had occurred in medical or surgical settings (46% and 32.7%, respectively). Nutritional data were available from 94 patients, fed either by parenteral or enteral routes, or both. The mean caloric intake was higher (29 kcal/kg/day) in patients who recovered than in those who did not (24 kcal/kg/day, p less than 0.01). A caloric intake above 35 kcal/kg/day resulted in an improved survival, independently of either patients' age or non-renal complications. Serum prealbumin and transferrin levels were higher in surviving patients than in those who died, 0.25 vs 0.16 g/l (p less than 0.001) and 1.7 vs 1.4 g/l (p less than 0.01), respectively. Nutritional support in ARF could be adapted according to the variations of these serum markers. Its influence on survival should be assessed with regard to the associated prognosis factors.

Acute Kidney Injury

Oral therapy in children with cholera: a comparison of sucrose and glucose electrolyte solutions.

We performed a double-blind trial comparing sucrose electrolyte oral solution with glucose electrolyte oral solution in children less than 5 years of age with severe cholera-like diarrhea. Of 111 patients studied (102 with bacteriologically confirmed cholera), 55 received sucrose solution and 56 received glucose solution. The success rates, as defined by the absence of the need to give unscheduled intravenous therapy, were similar in the two groups (73% and 77% in the sucrose and glucose groups, respectively). There was no difference in purging rates between the two groups. The primary determinant of success for oral fluid regardless of the sugar was the purging rate. Sucrose malabsorption was responsible for oral therapy failure in one child. This study demonstrates that sucrose is an effective alternative to glucose in the oral therapy solution, but either must be used in conjunction with intravenous solution when treating severe dehydrating diarrhea.

Administration, Oral

Disease due to enterotoxigenic Escherichia coli in Bangladeshi adults: clinical aspects and a controlled trial of tetracycline.

The clinical characteristics of disease due to enterotoxigenic Escherichia coli (ETEC) were determined in 88 adult males admitted to a hospital in Dacca, Bangladesh, with moderate to severe dehydration. Persons infected with ETEC strains producing both heat-labile toxin (LT) and heat-stable (ST) toxin had more dehydration and acidosis, longer duration of illness, and greater stool volume than persons infected with strains producing only ST. Tetracycline therapy, evaluated in 63 cases, resulted in slightly earlier termination of illness in patients with LT-ST strains but had no effect on illness in the patients with ST strains. In both groups of patients tetracycline shortened the duration of excretion of organisms. Because of its limited effectiveness and the generally excellent response of ETEC diarrhea to rehydration therapy alone, tetracycline is not warranted for use in treatment of ETEC diarrhea in adults in this population.

Adult

Randomized trial of high- and low-dose ampicillin therapy for treatment of severe dysentery due to Shigella dysenteriae type 1.

To establish optimal therapy for severe dysentery due to Shigella dysenteriae type 1 and Shigella flexneri, we compared in a prospective randomized trial two oral ampicillin doses (50 and 150 mg/kg per day) in 57 children and 39 adults in Dacca, Bangladesh. Clinical failure did not occur in either group, indicating that conventional doses need not be increased even in severe disease. Among children 3 years of age or under, bacteriological relapses tended to be more frequent in the low-dose group and were not related to serum levels of ampicillin, nutritional status, or the severity of colitis on admission. Therefore, we recommend that younger children be treated with 100 mg/kg per day of oral ampicillin.

Administration, Oral

Conditioned taste aversion elicited in anaesthetized rats by scorpion venom.

Conditioned saccharin aversion was elicited in rats by the use of scorpion venom. After 15 min of saccharin drinking, groups of rats were injected with venom, Nembutal, LiCl or isotonic saline. Two groups were anaesthetized 10 min after saccharin drinking and injected with venom or with LiCl. During retention test saccharin aversion was observed in the venom and LiCl groups. It is concluded that anaesthesia does not prevent conditioned taste aversion engram formation.

Anesthesia

Severe conditioned taste aversion elicited by venom of Russell's viper.

Conditioned taste aversion (CTA) established in rats by associating saccharin drinking with subsequent poisoning by Russell's viper venom. Retention test revealed 76 and 56% reduction of saccharin intake in venom and antivenom-venom groups. No CTA was observed in antivenom and control groups.

Animals

Identification of gallbladder typhoid carriers by a string device.

The efficiency of a gelatin capsule containing a nylon string for collection of duodenal specimens was investigated in carriers of Salmonella typhosa (typhi). Cultures of duodenal specimens obtained by means of the string capsule were compared with cultures of duodenal specimens obtained by a conventional duodenal tube and with stool cultures Duodenal contents obtained with either the string or tube were more often positive for S. typhosa than were stool cultures. The string, which is as efficient as tube collection but simpler and more comfortable, may be useful in identifying carriers of S. typhosa.

Adult

Oral hydration rotavirus diarrhoea: a double blind comparison of sucrose with glucose electrolyte solution.

Of 57 male children, aged 5 months to 2 1/2 years with rotavirus diarrhoea, 28 were given oral therapy with sucrose electrolyte solution and 29 were given glucose electrolyte solution in a randomised double-blind trial. All were rehydrated and remained so on oral therapy alone. These patients were compared with 44 children, also with rotavirus, who were treated only with intravenous hydration. The oral therapy and intravenous therapy groups did not differ clinically in the rate of rehydration or the rate of purging. Vomiting did not prevent the giving of oral therapy during hospital admission. Bangladeshi children with rotavirus diarrhoea have a defect of carbohydrate digestion but this defect does not prevent the use of a sugar electrolyte solution for oral hydration.

Administration, Oral

Hemolytic-uremic syndrome after shigellosis. Relation to endotoxemia and circulating immune complexes.

To investigate three possible causes of the acute hemolysis in the hemolytic-uremic syndrome, we studied prospectively 207 children and 34 adults with shigellosis in Bangladesh. Nineteen children showed acute hemolytic anemia, a leukemoid reaction, thrombocytopenia and oliguria; nine other had, in addition, a serum urea nitrogen level of over 100 mg per diciliter. Eight of the nine had pseudomembranous colitis, and six of the nine died. The frequency of bacteremia was similar in all grades of shigellosis. Circulating immune complexes were found in 10 of 20 patients with uncomplicated shigellosis and in four of six with severe hemolytic-uremic syndrome. Limulus assay for endotoxemia was positive in nine of 18 patients with hemolysis (50 per cent) and three of 61 with uncomplicated shigellosis (5 per cent) (P less than 0.001). These data support the hypothesis that severe colitis in shigellosis is associated with circulating endotoxin from the colon producing coagulopathy, renal microangiopathy and hemolytic anemia.

Adolescent

Single-dose doxycycline for cholera.

To determine the efficacy of single-dose doxycycline in the treatment of cholera, we carried out a randomized prospective trial in 65 patients. Treatment consisted of either a single dose of 200 mg of doxycycline (or 4 mg/kg in patients less than 15 years old) or multiple doses of doxycycline, 500 mg over 4 days (or 10 mg/kg in patients less than 15 years old). There were no differences between the groups in the volumes of intravenous fluid required, volumes of diarrheal stool, or durations of diarrhea. The mean duration of positive stool cultures for Vibrio cholerae was similar for the two groups, although in both groups several patients continued to excrete Vibrios in the stool for more than 3 days. Blood levels of antibiotic demonstrated that the doxycycline was absorbed in spite of the rapid transit time associated with severe diarrhea. These results suggest that although tetracycline remains the drug of choice for cholera, doxycycline is a reasonable alternative, and that a single dose of 200 mg (4 mg/kg in children) is effective clinically.

Adult