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Biomedical subjects

M A Rahman

Publications and source records attributed to M A Rahman.

At least 109 records · Page 6Linked to original sources
PubMed1990

Lung function in teenage Bangladeshi boys and girls.

Data on forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate were obtained in a group of 588 healthy and well-nourished (but not obese) Bangladeshi teenagers to establish normal values in this population. Bangladeshi girls in their early teens showed higher peak expiratory flow rates than boys of the same age but while this continued to rise in boys after the age of 15 years the peak expiratory flow rate in girls seemed to have attained its maximum values by that age. Correlations between sitting height and the lung function variables were found to be marginally greater than those with standing height. Prediction equations were calculated for each lung function variable with sitting and standing separately. Comparison of the results in our study with those reported from other ethnic groups indicate that Bangladeshi values are lower than those of Europeans, Jordanians or Chinese but not significantly different from those reported for Libyans. Since in practice, genetic, nutritional and environmental factors are not readily disentangled, norms for a given study population need to be derived from healthy subjects of similar background and ethnicity.

Adolescent↗
PubMed1990

The effects of propranolol or atenolol on the cardiovascular responses to central hypovolaemia in Europeans and Bengalees.

1. The effects of single oral doses of propranolol (80 mg), or atenolol (100 mg) on resting heart rate, blood pressure, forearm blood flow and forearm vascular resistance and on responses to central hypovolaemia, were compared with those of placebo in nine healthy European and nine healthy Bengalee volunteers, in a double-blind, three-period, cross-over study. 2. Atenolol induced a significant reduction in resting systolic blood pressure (SBP) in Europeans but not in Bengalees, although the bradycardic effects of atenolol were similar in both groups. Atenolol did not have any significant effect on forearm blood flow (FBF) or forearm vascular resistance (FVR) in either group. In the presence of propranolol (80 mg) there were no statistically significant falls in BP but there were significant bradycardias, falls in FBF and rises in FVR that were similar in Europeans and Bengalees. 3. In the presence of placebo Europeans exhibited significant falls in diastolic blood pressure (DBP) during lower body negative pressure (LBNP) of 20 and 30 mm Hg. Bengalees did not show falls in DBP during LBNP. However, there were no significant differences between DBP responses in Europeans and Bengalee subjects. Both Bengalees and European subjects showed similar reductions in FBF and FVR during LBNP of 30 mm Hg. 4. In the presence of propranolol, significant changes in forearm blood flow and forearm vascular resistance were evident in Bengalee subjects during LBNP of 20 mm Hg and 30 mm Hg, whereas in the Europeans significant changes in those variables did not occur at any level. The changes in FBF and FVR during LBNP of 20 and 30 mm Hg in Bengalee and European subjects were significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Effects of hypertonic peritoneal dialysis solutions on neutrophil superoxide production.

Superoxide produced by neutrophils plays an important role in the killing of bacterial pathogens. The effects of glucose-containing peritoneal dialysis solutions on superoxide production by canine and human neutrophils were studied. A significant decrement in superoxide generation was noted with the 2.27% and 3.86% glucose solutions. The results suggest that hypertonic peritoneal dialysis solutions curtail neutrophil superoxide generation.

Animals↗
PubMed1990

Superoxide generation by neutrophils after exposure to a conventional peritoneal dialysis solution for different time periods.

Neutrophils were isolated from canine blood and exposed to a conventional, acidic, lactate-containing peritoneal dialysis solution for 0, 2 and 4 minutes in one study and 0, 4, 7 and 10 minutes in another. Superoxide generation, expressed in nanomoles per million cells, was determined using a method based on the superoxide dismutase-inhibitable reduction of ferricytochrome c. Brief exposure of neutrophils to a conventional dialysis solution could significantly inhibit the generation of superoxide by neutrophils.

Animals↗
PubMed1989

Enhanced antibody responses to Epstein-Barr virus in HIV-infected homosexual men.

We investigated the association between human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) infections in 593 homosexual men. The status of EBV infection in this group was evaluated based on serological evidence of EBV-specific antibody responses. The geometric mean titers (GMT) of antibody to EBV capsid antigen (EBV-VCA) (1:154) and EBV early antigen (EA) (1:16) in 141 HIV-seropositive men were significantly higher than respective titers in 452 HIV seronegative men (1:95 and 1:12). Antibody titers to EBV were higher in HIV-infected men with lymphadenopathy than in asymptomatic HIV-seropositive men. However, these correlation were less evident in patients with AIDS-related complex. Elevated antibody titers to EBV were found to be independent of levels of total serum IgG. Cytomegalovirus (CMV) antibody titers were also found to be significantly increased among HIV-seropositive men, independent of total IgG. Antibody titers to EBV were not correlated with those to CMV in either HIV-seronegative or HIV-seropositive men. Subjects without evidence of HIV infection, but who had high antibody titers to EBV-VCA and EBV-EA, had elevated mean numbers of CD3+, CD4+, and CD8+ cells, and lower levels of CD4+/CD8+ cell ratios compared to subjects with low EBV-antibody titers. This study suggests that the elevated levels of circulating antibodies against EBV in homosexual men are associated with loss of control of latent EBV due to HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Contrast media-induced lipid peroxidation in the rat kidney.

Lipid peroxidation of biological membranes is often implicated in tissue injury. The authors compared the effects of ionic and nonionic contrast media (CM) on the induction of lipid peroxidation in rat kidney and its impact on renal function. Male Wistar rats weighing 200 to 230 grams were dehydrated for 24 hours and divided into 6 groups (n = 15/group). On day 0, groups 1 through 3 were injected with 25% glycerol (10 mL/kg, im) and rats from groups 4 through 6 received an equivalent amount of intramuscular saline. The next day, rats from groups 1 and 4 were injected with normal saline (10 mL/kg, iv); groups 2 and 5 received the ionic CM, diatrizoate, and groups 3 and 6 received the nonionic CM, iopromide. Each CM was tested at 10 mL/kg BW. At 24-hour intervals, 5 rats from each group were sacrificed. In rats injected with CM (diatrizoate or iopromide) alone, no changes in serum creatinine or kidney structure were demonstrated. In glycerol treated rats, a peak in serum creatinine was seen on day 2 which returned to normal level by day 4. Histologic changes included focal tubular damage and intraluminal debris. Malondialdehyde (MDA), a marker of lipid peroxidation concentration was higher than in controls (P less than 0.05). In diatrizoate-injected rats, increase in serum creatinine on day 4 was ten times higher than glycerol; severe morphological alterations in proximal tubules were noted and significant increases in renal MDA concentration were obtained (P less than .05). Iopromide (on day 4), caused a five-fold increase in serum creatinine compared with glycerol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Effects of bicarbonate-containing versus lactate-containing peritoneal dialysis solutions on superoxide production by human neutrophils.

Human neutrophils were isolated from healthy volunteers and exposed to either bicarbonate-containing (pH 7.4) or lactate-containing (pH 5.2) peritoneal dialysis solution in vitro. Superoxide production by neutrophils was measured by a method based on the superoxide dismutase-inhibitable reduction of ferricytochrome c. Bicarbonate-containing peritoneal dialysis solution was found to be superior to the lactate-containing one in facilitating the production of superoxide anion by human neutrophils.

Adult↗
PubMed1989

Role of prostaglandins and thromboxane in the control of renal hemodynamics in experimental liver cirrhosis.

Although there is considerable evidence that vasodilator prostaglandins such as prostaglandin E2 (PGE2) modulate renal hemodynamics in liver cirrhosis, the role of the vasoconstrictor thromboxane A2 (TXA2) is controversial. We measured renal hemodynamics and glomerular eicosanoid production in cirrhotic and control rats. Renal plasma flow, as estimated by para-aminohippurate clearance (CPAH) and glomerular filtration rate, as determined by inulin clearance (CIN), were comparable between groups; glomerular production of PGE2 and TXA2 (estimated by the metabolite thromboxane B2 [TXB2]) was slightly but not significantly higher in cirrhotic than in control rats (PGE2: 1060 +/- 142 pg/mg glomerular protein vs 854 +/- 288 pg/mg glomerular protein; TXB2: 782 +/- 103 pg/mg glomerular protein vs 468 +/- 104 pg/mg glomerular protein). Addition of serum from cirrhotic rats to the incubation media failed to increase eicosanoid production in glomeruli obtained from either cirrhotic or control rats. Cyclooxygenase inhibition with 5 mg/kg indomethacin, a dose sufficient to result in a 68% inhibition of glomerular PGE2 synthesis, decreased both CPAH (from 6.59 +/- 0.69 ml/min to 4.52 +/- 0.67 ml/min, p less than 0.05) and CIN (from 1.34 +/- 0.16 ml/min to 0.68 +/- 0.07 ml/min, p less than 0.01) in cirrhotic rats. Thromboxane synthesis inhibition with 1 mg/kg UK-38485, which resulted in an 84% decrease in glomerular TXB2, did not significantly affect either CPAH or CIN; however, there was a strong trend toward improvement in CIN (from 1.23 +/- 0.11 ml/min to 1.43 +/- 0.15 ml/min (0.05 less than p less than 0.1). Neither drug affected renal hemodynamics in control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Increased leukotriene B4 synthesis in immune injured rat glomeruli.

We examined glomerular synthesis of the 5-lipoxygenase metabolite, LTB4, in normal and immune-injured rat glomeruli. Glomeruli isolated from normal rats and from rats with nephrotoxic serum nephritis (NSN), passive Heymann nephritis (PHN) and cationic bovine gamma globulin (CBGG)-induced glomerulonephritis were incubated with the calcium ionophore A23187 (3 microM). Lipids in the glomeruli and media were extracted with ethyl acetate, and were purified and fractionated by HPLC. Immunoreactive-LTB4 (i-LTB4) was determined by radioimmunoassay on HPLC fractions with a detection limit of 50 pg of i-LTB4. A large peak of i-LTB4 that comigrated with authentic LTB4 was found exclusively in glomeruli isolated from the CBGG-injected rats. Addition of the lipoxygenase inhibitor BW755C (50 micrograms/ml) to glomerular incubation resulted in greater than 90% inhibition of i-LTB4. Synthesis of i-LTB4 by glomeruli from normal, NSN and PHN rats was undetectable. Glomerular LTB4 synthesis by CBGG-injected rats was confirmed by radiometric HPLC and by gas chromatography mass-spectroscopy (GC-MS) analysis. In order to rule out synthesis of LTB4 by neutrophils entrapped in the glomeruli, a group of rats received 1,000 rad total body x irradiation, with shielding of the kidneys before induction of CBGG glomerulonephritis. Despite greater than 95% reduction in total leukocyte count, glomerular synthesis of LTB4 remained enhanced. Augmented glomerular synthesis of the proinflammatory lipid, LTB4, in the CBGG model of glomerular disease could have an important role in the development of glomerular injury and proteinuria.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1988

Effect of diet on transaminase and arginase activities.

The composition of the diet greatly influences the enzyme activities of the liver. The effect of low carbohydrate diet on AST, ALT and arginase activities in liver and serum of rats was determined in the present study. Liver ALT and serum AST were significantly increased in animals fed on low carbohydrate diet, the activities of other enzymes remained unchanged.

Journal Article↗
PubMed1988

Hydroxyl radical scavengers ameliorate proteinuria in rat immune complex glomerulonephritis.

We examined the effect of the administration of different oxygen radical scavengers on the development of glomerulonephritis induced by cationic bovine gamma-globulin (cBGG). Treatment with the H2O2 scavenger catalase or the superoxide anion (O2-) scavenger superoxide dismutase (SOD) did not significantly reduce proteinuria. In contrast, treatment with the hydroxyl radical (OH.) scavengers dimethyl sulfoxide (DMSO) or dimethylthiourea resulted in significant decrements in proteinuria, from 156 +/- 20 mg/24 hours in saline solution--treated control rats to 70 +/- 17 mg/24 hours (p less than 0.05) and 37 +/- 10 mg/24 hours (p less than 0.01) in DMSO- and dimethylthiourea-treated rats, respectively. Therapy with DMSO for 5 days after induction of glomerular disease also resulted in amelioration of proteinuria, 10.0 +/- 5.0 mg/24 hours versus saline solution-treated rats, 67.6 +/- 16.2 mg/24 hours (p less than 0.005). OH. scavenger therapy did not influence glomerular morphology, glomerular immunoglobulin G (IgG), or complement deposition, or creatinine clearances of rats with glomerulonephritis. Furthermore, there were no significant differences in serum levels of C3 and C5 or anti-BGG antibody production between DMSO-treated rats and control rats. None of the radical scavengers administered altered the enhanced glomerular thromboxane synthesis characteristic of this model. Our results suggest that OH. generation mediates in part glomerular injury in cBGG-induced glomerulonephritis.

Animals↗
PubMed1988

Suppression of neutrophil superoxide production by conventional peritoneal dialysis solution.

The pH of conventional peritoneal dialysis solution is normally in the range of 5.0 to 5.5, because acid has been added during the manufacturing process to prevent caramelization of dextrose during sterilization. We studied the effects of normalizing the pH of conventional peritoneal dialysis solution on superoxide production by normal human neutrophils. At a pH of 6.0, superoxide generation was 4.07 +/- 2.56 (SD) nanomoles per million cells. With normalization of pH to 7.4, superoxide production was 19.3 +/- 7.3 (p less than 0.001). The results suggest that the unphysiologic acidity of conventional peritoneal dialysis solution has deleterious consequences on neutrophil superoxide formation.

Adolescent↗
PubMed1988

Complement and leukocyte independent proteinuria and eicosanoid synthesis in rat membranous nephropathy.

We examined the effect of complement depletion and leukocyte depletion on an experimental model of membranous nephropathy. Nephrosis was induced in 200-gm male Sprague-Dawley rats by priming with cationic bovine gamma-globulin in adjuvant on day 1 followed by intravenous challenge with antigen starting on day 10. No naive control rats had immunofluorescent deposits in glomeruli; urine protein was less than 10 mg/24 hour and glomerular thromboxane synthesis was 658 +/- 64 ng/mg glomerular dry weight. In contrast, all rats primed and challenged with cationic bovine gamma-globulin had intense granular capillary wall deposits of rats IgG, bovine gamma-globulin, C3 and C5; severe proteinuria (183 +/- 24 mg/24 hour) was observed, associated with a 3-fold increase in glomerular thromboxane (2,393 +/- 574 ng/mg, all p less than 0.01 versus naive controls). In some rats, administration of cobra venom factor and antiserum to rat C3, starting on day 8 was used to deplete complement; hemolytic C3 and C5 were less than 2% of normal at sacrifice. These rats had IgG and bovine gamma-globulin deposits, whereas they lacked glomerular C3 or C5. Proteinuria (209 +/- 28 mg/24 hour) and glomerular thromboxane (2,087 +/- 394 ng/mg) were markedly increased compared with control, but no different from normocomplementemic rats primed and challenged with cationic bovine gamma-globulin. In other rats, depletion of leukocytes was achieved by 1,000 R x-irradiation on day 7; at sacrifice, irradiated rats had 1,270 +/- 462 wbc/microliter versus 10,375 +/- 1,652 in nephrotic rats given no other treatment, with unaltered differentials. These rats had glomerular deposits of rat IgG, bovine gamma-globulin, C3 and C5 indistinguishable from nephrotic rats with normal leukocyte counts in intensity and distribution. Proteinuria (202 +/- 30) and glomerular thromboxane (2,358 +/- 189 ng/mg) were markedly elevated compared with naive controls, but were not different from the normocomplementemic or complement-depleted groups primed and challenged with antigen. An additional control group included rats primed with ovalbumin on day 1, irradiated with 1,000 R on day 7, and challenged with cationic bovine gamma-globulin starting on day 10. This group had granular capillary wall deposits of bovine gamma-globulin, but not deposits of IgG, C3, or C5; urine protein excretion (less than 10 mg/24 hours) and glomerular thromboxane synthesis (613 +/- 90) were not different from naive controls. Glomerular prostaglandin E2 synthesis did not differ among the five groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Role of vitamins in urolithiasis.

The serum vitamin A level of the lithiasis patients was found to be low, although vitamin A intake was not different from control subjects. Vitamin C level in blood was not significantly different in the patients as compared with control subjects. The control subjects and urolithiasis patients were also subjected to the oral supplementation of L-tryptophan and glycine. It was observed that neither oxalate nor xanthurenic acid increased in urine after loading. It was concluded that vitamin B6 deficiency does not exist in these cases.

Adult↗