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Biomedical subjects

K Alam

Publications and source records attributed to K Alam.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cross-reaction between a strain of Vibrio mimicus and V. cholerae O139 Bengal.

Of 200 isolates of Vibrio mimicus screened, one from water (N-57) agglutinated with V. cholerae O139 polyclonal antiserum (absorbed with a rough strain of V. cholerae only) and not with O139 polyclonal diagnostic antiserum (absorbed with the rough strain and V. cholerae O22 and O155). The antigenic relationship between V. cholerae 0139 and N-57 is of a,b-a,c type, where a is the common antigenic epitope and b and c are unique epitopes. Strain N-57 was assigned to a new serogroup of V. cholerae O194. It gave negative results in a monoclonal antibody-based rapid test and a PCR test specific for V. cholerae O139. It did not possess the ctx gene or produce cholera toxin. Antiserum to strain N-57 cross-protected infant mice against cholera on challenge with V. cholerae O139. Structural studies of the surface polysaccharides and studies of the rfb genes will shed more light on the extent of relatedness between V. mimicus N-57 and V. cholerae O139.

Agglutination Tests↗
PubMed1999

Analgesic effects of intra-muscular ketoprofen (Profenid) and pethidine for squint surgery in children.

Administration of analgesics before surgery can decrease the intra-operative anesthetic requirement and pain during the early post-operative period (pre-emptive analgesia). The objective of this study was to evaluate an intra-muscular preparation of ketoprofen as analgesic in mild to moderate pain in children. In a double-blind placebo-controlled study, 91 healthy ASA I or II children undergoing squint opthalmic surgery was undertaken in the Ophthalmic Services at King Abdel-Aziz University Hospital Riyadh. The postoperative analgesic effects of intra-muscular pethidine and ketoprofen, just after the induction of anesthesia were compared. Patients were randomized to receive ketoprofen (1 mg W kg-1), pethidine (1 mg W kg-1) or saline (0.1 ml W kg-1). Anesthesia was induced and maintained with halothane and nitrous oxide via a facemask. Post-operative pain was assessed by a blinded observer using an objective pain scale. Results revealed that the ketoprofen group had lower post-operative pain scores and required less frequent analgesic therapy in the early postoperative period compared to the pethidine and placebo groups. In contrast, there were no differences in pain scores or analgesic requirements between the pethidine and the placebo groups. It is concluded that the preoperative administration of intramuscular ketoprofen, but not pethidine, provided better postoperative pain control than placebo in children undergoing ophthalmic surgery.

Analgesics↗
PubMed1998

Attenuated antigenicity of ribonucleoproteins modified by reactive oxygen species.

Ribonucleoprotein (RNP) particles isolated from fresh goat liver nuclei were exposed to hydroxyl radical which induced modification in the gross structure of RNP particles. To evaluate the effect of hydroxyl modification on the antigenic properties of RNP and possible role of ROS-RNP in the initiation and development of SLE, enzyme immunoassays were carried out. SLE sera having high titre anti-DNA antibodies showed enhanced binding to hydroxyl modified RNP particles in comparison to unmodified RNP particles. In competition assay none of the SLE sera or isolated IgG showed preference for ROS-modified RNP particles over native RNP particles. These studies suggest that anti-RNP autoantibodies observed in subpopulation of SLE patients are generated by some other intra-or extracellular mechanisms and hydroxyl radical has probably no direct role in the initiation of antibodies.

Animals↗
PubMed1998

Characterization of the roles of hemolysin and other toxins in enteropathy caused by alpha-hemolytic Escherichia coli linked to human diarrhea.

Escherichia coli strains producing alpha-hemolysin have been associated with diarrhea in several studies, but it has not been clearly demonstrated that these strains are enteropathogens or that alpha-hemolysin is an enteric virulence factor. Such strains are generally regarded as avirulent commensals. We examined a collection of diarrhea-associated hemolytic E. coli (DHEC) strains for virulence factors. No strain produced classic enterotoxins, but they all produced an alpha-hemolysin that was indistinguishable from that of uropathogenic E. coli strains. DHEC strains also produced other toxins including cytotoxic necrotizing factor 1 (CNF1) and novel toxins, including a cell-detaching cytotoxin and a toxin that causes HeLa cell elongation. DHEC strains were enteropathogenic in the RITARD (reversible intestinal tie adult rabbit diarrhea) model of diarrhea, causing characteristic enteropathies, including inflammation, necrosis, and colonic cell hyperplasia in both small and large intestines. Alpha-hemolysin appeared to be a major virulence factor in this model since it conferred virulence to nonpathogenic E. coli strains. Other virulence factors also appear to be contributing to virulence. These findings support the epidemiologic link to diarrhea and suggest that further research into the role of DHEC and alpha-hemolysin in enteric disease is warranted.

Animals↗
PubMed1998

Teratoma of the liver--a case report.

A case of primary teratoma of the liver in a 10 months old male child is being reported for its rarity. It is the first case report in Indian literature.

Humans↗
PubMed1997

Evaluation of Teknaf Enteric Agar (TEA): A modified MacConkey's Agar for the isolation of Shigella dysenteriae type 1 and Shigella flexneri.

To develop a better and selective medium for the isolation of Shigella spp., MacConkey's Agar (MAC) was modified by adding potassium tellurite (K2TeO3) at a concentration of 1 microgram/ml. The formulation designated Teknaf Enteric Agar (TEA) was studied for the inhibitory effect of potassium tellurite on the growth of different enteric bacteria, and as a medium for isolating Shigella spp. from clinical stool samples (n = 3125). We observed that the growth of E. coli was effectively inhibited on TEA with no effect on the growth of S. dysenteriae type 1 and S. flexneri. A total of 2019 Shigellae were isolated through the combined use of TEA, MAC, and Salmonella-Shigella Agar (SS). On TEA, 1921 S. dysenteriae type 1 and S. flexneri were isolated as compared to 1765 from the combined use of MAC and SS. A total of 194 of S. dysenteriae type 1 and S. flexneri were exclusively isolated from TEA as compared to 38 which were only made from MAC and SS. We conclude that TEA significantly increased the overall isolation rate of Shigella spp. as compared to the combined use of MAC and SS (P < 0.0001), although it is not suitable for the isolation of S. sonnei.

Agar↗
PubMed1996

Monoclonal antibodies to the enterotoxin of Bacteroides fragilis: production, characterization, and immunodiagnostic application.

A monoclonal antibody, ICT11, specific for the toxin of enterotoxigenic Bacteroides fragilis (ETBF) neutralized the cytotoxic effect of the toxin on human colonic cell line HT-29/C1. In an evaluation using 115 diarrheal stool specimens and culture as the "gold standard," the assay showed a sensitivity of 85% and a specificity of 100%. An ICT11-based sandwich enzyme-linked immunosorbent assay showed a sensitivity of 100% and a specificity of 98% for direct detection of toxin from stool samples compared with those of culture. Thus, ICT11-based assays will be useful for screening for ETBF.

Antibodies, Bacterial↗
PubMed1995

Brain histaminergic system in mast cell-deficient (Ws/Ws) rats: histamine content, histidine decarboxylase activity, and effects of (S) alpha-fluoromethylhistidine.

The mast cell-deficient [Ws/Ws (White spotting in the skin)] rat was investigated with regard to the origin of histamine in the brain. No mast cells were detected in the pia mater and the perivascular region of the thalamus of Ws/Ws rats by Alcian Blue staining. The histamine contents and histidine decarboxylase (HDC) activities of various brain regions of Ws/Ws rats were similar to those of +/+ rats except the histamine contents of the cerebral cortex and cerebellum. As the cerebral cortex and cerebellum have meninges that are difficult to remove completely, the histamine contents of these two regions may be different between Ws/Ws and +/+ rats. We assume that the histamine content of whole brain with meninges in Ws/Ws rats is < 60% of that in +/+ rats. So we conclude that approximately half of the histamine content of rat brain is derived from mast cells. Next, the effects of (S) alpha-fluoromethylhistidine (FMH), a specific inhibitor of HDC, on the histamine contents and HDC activities of various regions of the brain were examined in Ws/Ws rats. In the whole brain of Ws/Ws rats, 51 and 37% of the histamine content of the control group remained 2 and 6 h, respectively, after FMH administration (100 mg/kg of body weight). Therefore, we suggest that there might be other histamine pools including histaminergic neurons in rat brain.

Alcian Blue↗
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

Controlled study of Escherichia coli diarrheal infections in Bangladeshi children.

Diarrheal diseases are highly prevalent in Bangladesh. However, the relative contribution of diarrheagenic Escherichia coli organisms--those that are enterotoxigenic (ETEC), enteropathogenic (EPEC), enteroinvasive, enterohemorrhagic, enteroaggregative, and diffuse adherent--to diarrhea in Bangladeshi populations is not known. With DNA probes specific for these diarrheagenic E. coli strains, we analyzed fecal E. coli from 451 children up to 5 years of age with acute diarrhea seeking treatment at a Dhaka hospital and from 602 matched control children without diarrhea from July 1991 to May 1992. Enteroinvasive E. coli was not isolated from any children; enterohemorrhagic E. coli was not isolated from any diarrheal children but was isolated from five control children; enteroaggregative and diffuse adherent E. coli strains were isolated with similar frequencies from children with and without diarrhea, thereby showing no association with diarrhea; ETEC was significantly associated with diarrhea in the diarrheal children as a whole and especially in the age groups of 0 to 24 months and 37 to 48 months (further analysis suggests an association with diarrhea for the heat-stable toxin only and for both heat-labile- and heat-stable-toxin-producing ETEC only); and EPEC was significantly associated with diarrhea in the diarrhea group as a whole and particularly in infants up to 1 year of age. Further analysis suggested that EPEC strains of only the traditional serogroups were significantly associated with diarrhea. ETEC and EPEC infections peaked during warm months. Our data thus suggest that EPEC and ETEC are important causes of acute diarrhea in children in this setting.

Bangladesh↗
PubMed1995

Primary hepatocellular carcinoma and viral hepatitis B and C infection in Bangladeshi subjects.

Potential risk factors for the development of primary hepatocellular carcinoma and the prevalence and role of infection with viral hepatitis B and hepatitis C were investigated in 54 adult patients of Bangladeshi origin (45 male, age range 20-75 years), comprising 46 patients resident in Bangladesh (Group 1) and 8 patients who had emigrated to the UK 10-20 years previously (Group 2). Of the 46 patients in Group 1 (37 male), 16 had hepatocellular carcinoma, 10 had uncomplicated cirrhosis, and 20 had a clinical history of chronic viral hepatitis of more than 6 months' duration. Total hepatitis B virus marker positivity was 82.6%, significantly higher than in Group 2 patients (P < 0.001). Thirty-six per cent were hepatitis B surface antigen positive, 66% were hepatitis Be antigen positive and 45.3% were positive for hepatitis C virus antibody. Taking only the 16 patients with hepatocellular carcinoma, hepatitis B surface antigen positivity was 38%, hepatitis Be antigen 66% and positivity to hepatitis C virus antibody was 56%. The 8 patients with hepatocellular carcinoma in Group 2 were all male and aged between 45 and 56 years. Of these, 3 (38%) cases were positive for hepatitis B surface antibody and none was positive for hepatitis B surface antigen or antibody to hepatitis C virus (3 cases tested). Presenting features of HCC in the two groups differed with a short clinical history of tender abdominal mass in Group 1 and a gradual onset of jaundice in Group 2 UK-resident Bangladeshi subjects.

Adult↗
PubMed1994

Isolation of enterotoxigenic Bacteroides fragilis from Bangladeshi children with diarrhea: a controlled study.

We undertook a controlled study of children younger than 5 years in Bangladesh to determine whether enterotoxigenic Bacteroides fragilis (ETBF) was associated with diarrhea in this population. ETBF was isolated from 22 (6.1%) of 358 patients and 5 (1.2%) of 425 controls (P = 0.0001). In children younger than 1 year, however, low isolation rates (2 to 3%) were found in both patients and controls. In children older than 1 year, the rates were significantly higher in children with diarrhea (16 [9%] of 177) than in controls (2 [1%] of 264; P = 0.00001). When children with mixed infections with other known diarrheal pathogens were removed, the differences in children older than 1 year were still significant (7 [4%] of 177 versus 2 [1%] of 264; P = 0.033). The syndrome associated with ETBF was secretory in nature, with watery diarrhea, and of mild severity. These epidemiological and clinical findings are similar to those from a previous study of White Mountain Apaches in the United States and are the first to suggest that ETBF may also be an important diarrheal pathogen in other geographic areas and in the developing world where diarrhea is highly endemic.

Bacteroides Infections↗
PubMed1994

Decrease in ornithine decarboxylase activity after eradication of Helicobacter pylori.

OBJECTIVE: Our aim was to determine whether gastric mucosal ODC activity is altered after successful eradication of HP. Recent reports have suggested that Helicobacter pylori (HP) infection of the stomach is associated with the development of gastric cancer. Gastrointestinal cancers usually do not arise de novo; a series of mucosal changes leading to neoplastic transformation and degrees of dysplasia are believed to precede the development of cancer. These conditions are associated with increased cellular proliferation. Ornithine decarboxylase (ODC) activity is induced by factors that stimulate cellular proliferation, and has been shown to be elevated in gastrointestinal neoplasia, including gastric cancer. METHODS: Gastric antral and body biopsies were obtained from 17 HP-positive patients at endoscopy, for ODC activity and histology (including Warthin Starry stain) before and 4-6 wk after successful triple therapy. RESULTS: Patients included 12 males and five females, with a mean age of 55 yr (27-73 yr). Mean ODC activity (in pmol CO2/mg protein/h) was significantly decreased after eradication of HP, compared with pretreatment levels in antral (147 +/- 26 vs. 80 +/- 15) and body mucosa (76 +/- 21 vs. 20 +/- 5) (p < 0.05). CONCLUSION: Successful eradication of HP decreases mucosal proliferative activity, as reflected by decreased ODC activity. We speculate that by decreasing mucosal proliferative activity, HP eradication may help decrease the subsequent risk of gastric cancer.

Adult↗
PubMed1993

The effect of hydroxyl radical on the antigenicity of native DNA.

Hydroxyl free-radical mediated in vitro modification of native calf thymus DNA showed single-strand breaks, decrease in melting temperature and structural alteration of purine and pyrimidine bases. Experimentally induced antibodies against modified DNA exhibited polyspecificity. Native DNA, RNA and synthetic polynucleotides in B-conformation were found to be an effective inhibitor of induced antibody-immunogen interaction. Naturally occurring human anti-DNA autoantibodies showed enhanced recognition of modified DNA as compared to native polymer. IgG isolated from anti-DNA antibody-positive SLE sera by Protein A-Sepharose 4B chromatography were affinity purified on nDNA-(polylysyl-Sepharose 4B) matrix. In competitive binding experiments, the affinity-isolated IgG showed almost equal recognition of both native DNA and hydroxyl radical modified DNA. The possible role of hydroxyl radicals in the etiopathogenesis of SLE has been discussed.

Animals↗