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Biomedical subjects

H Rahman

Publications and source records attributed to H Rahman.

At least 55 records · Page 3Linked to original sources
PubMed1995

Ethanol neuronotoxicity in the embryonic chick brain in ovo and in culture: interaction of the neural cell adhesion molecule (NCAM).

The present study was undertaken to investigate the involvement of NCAM in the neuroteratogenic effects of ethanol demonstrated by us and others. In the first experiment we examined the effect of in-ovo ethanol exposure on expression of NCAM in various regions of the embryonic CNS throughout development. Chick embryos received ethanol (10 mg/50 microliters/day) or saline (control) at days 1-3 of development (E1-E3), were sacrificed at various embryonic ages and whole brain (WB), cerebral hemispheres (CH) and cerebellum (CE) processed for SDS-polyacrylamide gel electrophoresis. The normal developmental profile of NCAM in the chick brain exhibited the same dynamics as previously reported by others. When compared to age-matched control brains, an increase was observed in expression of high molecular weight forms of NCAM in cerebral hemispheres between E8 and E10. These bands represented highly sialated (> 180 kDa) forms of NCAM. In fact, the NCAM hand from ethanol-treated embryos at E8 migrated at a higher molecular weight than did its control counterpart, indicating an increase in sialic acid content. In contrast, no clear change was observed in NCAM expression in cerebellum from E10 through E20 as a result of ethanol exposure. In the second experiment, we examined the involvement of NCAM in the alterations in neuronal growth patterns observed in ethanol-exposed cultures. Neuroblast-enriched cultures derived from three-day-old whole chick embryos (E3WE) were maintained on poly-L-lysine pre-coated Petri dishes in DMEM+5% fetal bovine serum with or without 50 mM ethanol. Cultures were fixed at 3, 6 or 9 DIV and co-stained for NCAM and neurofilament (160 kDa). E3WE cultures exhibited intense NCAM immunoreactivity at 3 and 6 DIV decreasing by 9 DIV.NCAM positive structures included all neuronal perikarya, neuritic processes and growth cones. Addition of 50 mM ethanol to the medium resulted in profound alterations in growth patterns of developing neurons which continued to exhibit intense NCAM staining. Ethanol-induced changes in the developmental profile of NCAM expression (i.e. increased sialation) in cerebral hemispheres correspond temporally with the shift in neuronal phenotype from cholinergic to catecholaminergic and GABAergic which we have reported previously. Changes in the normal pattern of cellular contact and interaction as a result of altered NCAM expression may influence establishment of neurotransmitter phenotype. Findings from this study support the view that NCAM may be involved both directly and indirectly in shaping of the CNS during development and we speculate that ethanol neuroembryotoxicity uncouples this relationship.

Animals↗
PubMed1995

Immunogenicity and antigenic relationship of Salmonella enterotoxin with other enterotoxins.

The immunogenicity and antigenic relationship of Salmonella enterotoxin with other enterotoxins were studied. The purified enterotoxin of Salmonella typhimurium strains was immunogenic in rabbits and antiserum produced against it completely neutralized the enterotoxic activity of purified as well as crude enterotoxins. The Salmonella enterotoxin did not cross-react with cholera toxin, heat-labile enterotoxin of Escherichia coli or Shiga toxin. On the other hand, enterotoxins produced by different serotypes of Salmonella were antigenically related. Heat, pH and proteolytic enzymes had not only adversely affected the enterotoxigenicity but also the antigenicity of the Salmonella enterotoxin. However, formalin was found to completely destroy the enterotoxigenicity of enterotoxin without affecting the antigenicity. Formalin-treated enterotoxin may thus be tried as a vaccine to prevent the diarrhoeal syndrome induced by enterotoxigenic salmonellae.

Animals↗
PubMed1995

Development of an improved animal model of shigellosis in the adult rabbit by colonic infection with Shigella flexneri 2a.

Rabbits are not usually susceptible to intestinal Shigella infection without extensive pretreatment, including starvation and administration of antimicrobial, antimotility, and toxic agents (carbon tetrachloride). Most animals infected this way die rapidly and do not always develop colonic lesions and signs of dysentery. We describe here a successful experimental infection in the adult rabbit which does not require preparatory treatment and which reproduced characteristic features of human shigellosis. Unstarved, untreated adult rabbits were infected by direct inoculation of virulent Shigella flexneri 2a (10 ml of 10(7) bacteria per ml) into the proximal colon after ligation of the distal cecum (cecal bypass). Within 24 h of infection, most inoculated animals consistently developed clinical dysentery, characterized by liquid stool mixed with mucus and blood, leukocytosis, anorexia, and weight loss. Histologically, there were edema, exudation, superficial ulceration, and polymorphonuclear infiltrations in the lamina propria; crypt abscess formation; focal hemorrhages; and the presence of immunohistochemically stained S. flexneri in the colonic mucosa. Successful bacterial colonization was indicated by the isolation of the challenge strain of S. flexneri 2a from the colonic contents. None of the control rabbits challenged with nonvirulent S. flexneri or without cecal bypass developed dysentery or colitis. We conclude that successful Shigella infection can be induced by direct colonic inoculation with virulent S. flexneri 2a in adult rabbits without starvation and pretreatment. The colitis is dependent on the virulence of the bacteria and on the cecal bypass. This model should be useful in studies of the immunopathogenesis of Shigella infection.

Animals↗
PubMed1995

Study of hemagglutinating property of enteroinvasive Escherichia coli from various geographical locations.

Thirty-four strains of enteroinvasive Escherichia coli (EIEC) were examined for their ability to agglutinate erythrocytes from different animal species. All strains cultured in Casamino acid-yeast extract medium in the presence of 1 mM CaCl2 at 37 C for 16-22 hr induced maximal expression of hemagglutination (HA) of broad spectrum erythrocytes. The strongest HA was observed with guinea-pig erythrocytes followed by human (O type), rat, mouse, rabbit and sheep erythrocytes. All the strains failed to agglutinate chicken erythrocytes. HA was resistant to D-mannose, D-glucose, D-galactose, L-fucose, and D-fructose. Also HA was resistant to ethylene diamine tetraacetic acid (EDTA) and Na metaperiodic acid, an oxidizing agent. However, it was heat labile and completely inhibited by proteolytic enzymes such as proteinase K and trypsin, suggesting that the possible hemagglutinin of EIEC associated with the cell surface is a proteinaceous substance.

Animals↗
PubMed1994

Neuroblast cell death in ovo and in culture: interaction of ethanol and neurotrophic factors.

We used two experimental paradigms to examine the influence of the neurotrophins, NGF, EGF, and bFGF on normal neuroblast survival and also after ethanol insult. In the first paradigm, chick embryos received in ovo at embryonic day 1 and 2 (E1 and E2) saline (control) ethanol (10mg/50 microliters/day), NGF (50 ng/50 microliters/day), or EGF (25 ng/50 microliters/day), or ethanol+NGF or EGF. At E3, cultures were prepared from whole embryos separately from each group. At C2, all cultures were labeled with [3H]thymidine and assessed for effects or neuronal survival. In the second paradigm, cultures were prepared from 3-day-old whole embryos and at C0, cultures were treated with either ethanol (50 mM) alone, NGF (50 ng/ml) alone, EGF (25 ng/ml) alone, bFGF (50 ng/ml) alone, or were treated concomitantly with ethanol plus one of the neurotrophins; control had only the culture medium, DMEM + 5% FBS. We obtained the following findings. 1) Cultures derived from embryos treated with either of the three neurotrophins exhibited a higher neuronal survival as compared to controls (1st paradigm). 2) The survival-promoting effect was also observed when the neurotrophins were added directly to the cultures (2nd paradigm). 3) As reported previously, cultures derived from ethanol-treated embryos exhibited a marked decline in neuronal survival as compared to controls. 4) All three neurotrophins attenuated the decline in neuronal survival produced by ethanol. The 'rescuing' effects of the neurotrophins support our early hypothesis that ethanol administration during early neurogenesis interferes with microenvironmental trophic signals essential for neuroblast survival and differentiation.

Animals↗
PubMed1994

Purification and characterization of enterotoxic moiety present in cell-free culture supernatant of Salmonella typhimurium.

The enterotoxic moiety present in the cell-free culture supernatants of Salmonella typhiurium strains (p/536 and p/603) was purified to apparent homogeneity by salt precipitation with ammonium sulphate and successive chromatography through Sephadex G-100 and G-200 columns. It was non-dialysable, heat labile at 90 degrees C and active within pH 6-8. Its activity was completely lost on treatment with trypsin, protease and papain. The enterotoxin appeared to be of high molecular weight (100 kDa) and was highly immunogenic in rabbit. Antigenically, it was not related to cholera toxin, Shiga toxin or the heat labile enterotoxin of Escherichia coli. It did not bind to the GM1 ganglioside. The enterotoxic, delayed permeability and CHO cell elongation activities were attributed to a single protein moiety.

Animals↗
PubMed1994

The critical period for ethanol effects on cholinergic neuronal expression in neuroblast-enriched cultures derived from 3-day-old chick embryo: NGF ameliorates the cholinotoxic effects of ethanol.

Studies from our laboratory have established that ethanol exerts morphological and biochemical neurotoxic effects during early neuroembryogenesis in the chick brain both in ovo and in culture. In the present study, we further localized the critical period for ethanol effects on cholinergic neuronal expression using neuroblast-enriched cultures derived from 3-day-old chick embryos. Moreover, we report that NGF attenuated the cholinotoxic effects of ethanol. We used the following experimental paradigms: cultures treated with ethanol alone either C0-C3 or C4-C10; NGF alone C0-C4 or C4-C10; ethanol and NGF given concomitantly; ethanol given first then replaced with NGF in the medium; or NGF given first then replaced with ethanol in the medium. The results revealed: (1) the cholinotoxic effect of ethanol occurs between culture days C0 and C4 with day 3 appearing to be most critical; (2) similarly, the critical period for the cholinotoxic effects of NGF is during early neuroblast differentiation, culture days C0-C4; (3) NGF can prevent the cholinotoxic effects of ethanol only if both ethanol and NGF are given concomitantly or if ethanol is given first, then culture is replaced with NGF-containing medium.

Acetylcholine↗
PubMed1994

Interruption of rotavirus spread through chemical disinfection.

INTRODUCTION: Rotaviruses, which are among the most important infectious causes of acute diarrhea, frequently cause outbreaks in hospitals, daycare centers, schools, and nursing homes. These viruses can remain viable on inanimate surfaces for many days and infectious rotavirus particles have been recovered from hands and a variety of surfaces and objects. Casual contact can lead to the transfer of these viruses from contaminated to clean surfaces. Therefore, animate and inanimate surfaces may play a complementary role in the spread of these viruses. OBJECTIVE: In this study, we compared the capacity of a disinfectant spray (0.1% o-phenylphenol and 79% ethanol), a domestic bleach (6% sodium hypochlorite diluted to give 800 ppm free chlorine), a quarternary ammonium (quat)-based product (7.05% quat diluted 1:128 in tap water), and a phenol-based product (14.7% phenol diluted 1:256 in tap water) to interrupt the transfer of a human rotavirus (DS-1) from stainless steel disks to fingerpads of volunteers with a 10-second contact at a pressure of 1 kg/cm2. DESIGN: Each disk received a 10 microL inoculum containing 1.0 x 10(4) to 7.0 x 10(4) plaque-forming units (PFU) of the virus suspended in 10% feces. The inoculum was dried for 1 hour and overlaid with 20 microL of either tap water or the test product. RESULTS: A 10-minute exposure to tap water reduced the virus titer by 52.3% +/- 11.7%. The disinfectant spray was able to reduce virus infectivity by > 99.99% after a contact of 3 to 10 minutes. The loss in virus infectivity after a 10-minute treatment with the quat was almost the same (54.7% +/- 17.8%) as seen with tap water. The activities of the bleach and the phenolic were very similar with losses in PFU of 97.9% +/- 0.4% and 95% +/- 5.36%, respectively. No detectable virus was transferred to fingerpads from disks treated with disinfectant spray, the bleach, and the phenolic. Contact of the fingerpads with tap water- or quat-treated disks resulted in the transfer of 5.6% +/- 1.1% and 7.6% +/- 2.5% of the remaining infectious virus, respectively. CONCLUSION: These findings emphasize the care needed in the selection of environmental surface disinfectants in preventing the spread of rotaviral infections.

Adult↗
PubMed1994

Purification & antigenicity of Salmonella newport enterotoxin.

The enterotoxic moiety present in cell free culture supernatant (CFCS) of S. newport strains (MP/120 and BM/704) was purified and antigenically characterised. Purification was achieved to homogeneity by salt precipitation, dialysis and successive gel filtration through Sephadex G-100 and G-200 columns with the help of FPLC set. It was non-dialysable and purified enterotoxin yielded a single protein band in PAGE. It appeared to be of high molecular weight (100 KDa) and highly immunogenic in the rabbit. Antigenically, it was not related to cholera toxin, Shiga toxin or heat-labile enterotoxin of Escherichia coli.

Antibody Formation↗
PubMed1993

Early in ovo exposure of chick embryos to ethanol prevents the neuronotrophic effects of intracerebral NGF administration on cholinergic phenotypic expression.

We have reported that ethanol administration during early neuroembryogenesis significantly alters neuronal phenotypic expression. In addition, previous findings have indicated that ethanol may interfere with the neurotrophic effects of NGF. In this study, we examined the cholinergic neuronal response to NGF given intracerebrally to embryos at embryonic day 8 (E8) which were exposed to ethanol in ovo via the air sac at E1-3. We found that doses of NGF ranging from 0.01 to 1 ng/2 microliters/embryo given intracerebrally to untreated embryos at E8, and sacrificed at E10, significantly increased choline acetyltransferase (ChAT) activity, the marker for cholinergic neuronal expression. This response was most marked in spinal cord as compared with the low response observed in cerebral hemispheres. In control embryos treated with saline at E1-3 and then receiving NGF intracerebrally at E8, ChAT activity in the spinal cord increased with increasing NGF doses; the highest value was obtained with 0.1 ng NGF. In contrast, in ethanol-treated embryos, ChAT activity was not affected by intracerebral administration of NGF and, in fact, the highest dose (0.1 ng) produced a decrease in ChAT activity. We conclude that: (1) intracerebral administration of NGF produces differential cholinotrophic effects in the embryonic chick CNS; and (2) exposure to ethanol during early neuroembryogenesis interferes with the cholinotrophic effects of NGF.

Acetylcholine↗
PubMed1993

Ethanol exerts differential effects on high affinity choline uptake in neuron-enriched cultures from 8-day-old chick embryo cerebral hemispheres.

Neuronal-enriched cultures were prepared from 8-day-old chick embryo cerebral hemispheres and exposed to ethanol (50 mM) from day 4 to 8 in culture. At day 8, both control and ethanol-treated cultures were processed for [3H]choline uptake in situ. Uptake was performed on cultures containing either Na(+)-plus or Na(+)-free (Li+) HEPES buffer. Total choline uptake as well as Na(+)-dependent and Na(+)-independent choline uptake were calculated. The Km and Vmax were calculated using the Lineweaver-Burke analysis. Our analysis of the data revealed that ethanol-treated cultures exhibited two values for Vmax, one similar to that found in control cultures and one significantly lower than controls. No differences were observed in Km values between control and ethanol-treated cultures. We interpret the low Vmax to represent a population of cholinergic neurons which have been arrested at an immature stage as a result of ethanol insult.

Animals↗
PubMed1993

Silicone granulomatous reactions after first metatarsophalangeal hemiarthroplasty.

We reviewed 55 patients (78 feet) who had undergone silicone hemiarthroplasty of the first metatarsophalangeal joint for hallux valgus (40) or hallux rigidus (38). At a mean period of 4.5 years (1 to 11), 56 feet had radiological evidence suggestive of silicone granulomatous disease. The frequency and severity of the changes increased with time from the operation. Histological material from three revisions confirmed the presence of silicone granulomata. We recommend that the operation of silicone hemiarthroplasty for hallux valgus and hallux rigidus be abandoned.

Female↗
PubMed1993

Cerebral palsy.

In a prospective study it was found that cerebral palsy constituted 0.29% of total paediatric outdoor cases during the study period of 1988-1990. Seventy-five children suffering from cerebral palsy were studied at SN Children Hospital, Allahabad. Male to female ratio was 1:2. There were 42.8% cases who belonged to the age between one and 2 years. Hypertonic cases were predominant over hypotonic cases (3:1). Hemiplegia was commonest (68%) while triplegia was least common (2.7%). There were 24.5% cases who were mentally retarded. Hypertonic cases improved more frequently than hypotonic cases. An early management by paediatric physiotherapy may play an important role in the treatment of cerebral palsy.

Cerebral Palsy↗
PubMed1992

Salmonella cytotonic and cytolytic factors: their detection in Chinese hamster ovary cells and antigenic relatedness.

Thirty nine strains of Salmonella belonging to 14 different serotypes were screened for the production of cytotonic and cytolytic factors by assayed Chinese hamster ovary (CHO) cells. The cell-free culture supernatants (CFCS) of 32 isolates caused elongation and increase in size of CHO cells while the CFCSs completely lysed the cells. The cytotonic effect in CHO cells correlated precisely with fluid the CFCSs completely lysed the cells. The cytotonic effect in CHO cells correlated precisely with fluid accumulation in the rabbit ligated ileal assay in that 24 isolates yielded positive results in both assays and 13 were found negative in both. Antiserum to S. typhimurium enterotoxin, but not that to cholera toxin or Shiga toxin, neutralized the cytotonic activity present in the CFCS and reacted with the latter in immunodiffusion and coagglutination tests. The cytolytic factor produced by two strains reacted neither with antiserum to Salmonella enterotoxin nor with that the Shiga toxin.

Agglutination Tests↗
PubMed1992

Evaluation of Biken test for detection of Salmonella enterotoxin.

Biken test by using antiserum to purified Salmonella enterotoxin (SE) was standardized and carried out to screen salmonellae for their enterotoxigenicity. As many as 101 strains of Salmonella belonging to 15 different serotypes isolated from foods of animal origin were subjected to Biken test. Of these, 68 (67.32%) were found seropositive. The test correlated with the rabbit ligated ileal loop (RLIL) test completely for the detection of enterotoxin producing salmonellae with 24 test strains. However, 5 of the 13 strains which were negative in the RLIL test, yielded positive results with the Biken test.

Animals↗
PubMed1992

Surgical manifestations of ascariasis in childhood.

Amongst 50 patients with surgical complications of Ascaris lumbricoides 35 patients (70%) were treated conservatively and 15 patients (30%) required surgical intervention which included squeezing of worms to distal colon, resection and anastomosis of ileum, appendicectomy and peritoneal lavage. Intestinal perforation was observed in 3 cases. Two patients (4%) died because of postoperative complications. Those presenting with subacute intestinal obstruction had no mortality or morbidity. Although a large number of roundworms were seen in the jejunum, the obstruction was generally observed in the distal ileum.

Anthelmintics↗