Osteosarcoma of the mandible.
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Antineoplastic Agents↗
Biomedical subjects
K Alam
Publications and source records attributed to K Alam.
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↗
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↗
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↗
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↗
Lack of cross-protection against diarrhea due to Vibrio cholerae O139 (Bengal strain) after oral immunization of rabbits with V. cholerae O1 vaccine strain CVD103-HgR.
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Administration, Oral↗
Lack of cross-protection against diarrhea due to Vibrio cholerae O1 after oral immunization of rabbits with V. cholerae O139 Bengal.
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Animals↗
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↗
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↗
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↗
Role of Shigella dysenteriae type 1 slime polysaccharide in resistance to serum killing and phagocytosis.
Shigella dysenteriae type 1 produce a slime polysaccharide when cultivated in vivo in adult rabbit ileal loops or in vitro in casamino acid yeast extract broth medium which promotes hemagglutination of these bacteria. Seven strains of S. dysenteriae 1 grown in vitro and in vivo and possessing slime polysaccharides resisted killing by normal human serum as compared to bacteria grown under conditions which do not stimulate the production of capsular polysaccharide and did not resist serum killing (mean survival 72% for in vitro growth and 73% for in vivo growth conditions favoring capsule production vs < 2% for growth conditions which do not favor capsule production; P < 0.001 for both comparisons). Similar differences were observed when killing was assessed by phagocytosis (62-78% vs < 2%; P < 0.001). We conclude that capsular polysaccharide may be an additional virulence factor of S. dysenteriae 1.
Animals↗
DNA probe analysis of diarrhoeagenic Escherichia coli: detection of EAF-positive isolates of traditional enteropathogenic E. coli serotypes among Bangladeshi paediatric diarrhoea patients.
Escherichia coli isolates from all surveillance patients less than or equal to 20 months of age seen for diarrhoea at the Dhaka Clinical Treatment Facility of the International Centre for Diarrhoeal Disease Research, Bangladesh between March 1 and August 31, 1988, were collected and hybridized with DNA probes to assess the potential importance of diarrhoeagenic E. coli among paediatric patients in Bangladesh. Of 396 patients evaluated, 18% were infected with enteropathogenic E. coli (EPEC) adherence factor (EAF)-positive E. coli, 23% were infected with enterotoxigenic E. coli (ETEC), 9% were infected with Shiga-like toxin-positive E. coli, and 13% were infected with diffuse adhesiveness-positive E. coli. None were infected with enteroinvasive E. coli. Ten percent of patients were colonized with more than one type of potential diarrhoeagenic E. coli. The majority of EAF-positive isolates were of traditional EPEC O:H serotypes. Although this was not a case-control study, the large number of EPEC and ETEC, which are recognized enteric pathogens, suggests these organisms are important causes of diarrhoeal diseases in this pediatric population.
Bangladesh↗
Sharing of virulence-associated properties at the phenotypic and genetic levels between enteropathogenic Escherichia coli and Hafnia alvei.
Seven strains of Hafnia alvei isolated from diarrhoeal stools of children resembled enteropathogenic Escherichia coli (EPEC) in that they produced attaching-effacing (AE) lesions in rabbit ileal loops and fluorescent actin staining in infected HEp-2 cells. In addition, a DNA probe from a chromosomal gene required by EPEC to produce AE lesions, hybridised to chromosomal DNA from all seven H. alvei strains. These findings indicate that there is a sharing of virulence-associated properties at the phenotypic and genetic levels by H. alvei and EPEC. H. alvei strains with these properties should be considered diarrhoeagenic.
Bacterial Adhesion↗
Naturally occurring SLE anti-DNA antibodies recognize unique conformation on DNA-lysine photoadduct.
Native calf thymus DNA has been covalently modified with lysine under UV-A light. Human autoantibodies on purification through affinity column of native DNA linked to polylysyl-Sepharose 4B showed almost equal recognition of DNA and photoadduct. The recognition of DNA-lysine photoadduct by the affinity-purified autoantibodies might be helpful in understanding their origin in SLE vis-à-vis the role of positively charged amino acids in the pathogenesis of autoimmune diseases.
Animals↗
Pathogenesis of Providencia alcalifaciens-induced diarrhea.
Providencia alcalifaciens is a member of the family Enterobacteriaceae. There are reports that P. alcalifaciens can cause diarrhea, but the mechanism(s) by which it causes diarrhea is known. We studied P. alcalifaciens isolated from a child and two adults with diarrhea for enteropathogenicity. The three isolates did not exhibit any characteristic adherence to cultured HEp-2 cell monolayers, and they did not produce enterotoxins, cytotoxins, or keratoconjunctivitis in the Sereny test. Two isolates invaded cultured HEp-2 cell monolayers, producing localized bacterial clusters and actin condensation. The pattern of actin condensation was different from that produced by enteropathogenic Escherichia coli but similar to that produced by Shigella flexneri. Invasion and actin condensation were poor for the third isolate. Histology of adult rabbit small intestinal loops inoculated with all three isolates revealed bacterial attachment to, penetration of, and microulcer formation on the surface epithelium and hyperemia, edema, and polymorphonuclear cell infiltration of lamina propria. All the isolates produced diarrhea in rabbits with removable intestinal ties, and some of these rabbits developed hindlimb paralysis. Intestinal histology of the rabbits with removable intestinal ties which developed diarrhea showed changes similar to that in adult rabbits on which ileal loop assays had been performed. Transmission electron microscopy of intestinal tissues also confirmed tissue penetration by the isolates. Nerve tissue histology of two rabbits that developed hindlimb paralysis showed focal mononuclear cell infiltration around peripheral nerve sheaths. It is concluded that some strains of P. alcalifaciens are enteropathogenic and that they cause diarrhea by invading the intestinal mucosal epithelium. However, the relevance to human disease of the hindlimb paralysis observed in this animal model is not clear.
Animals↗
Characterization of Aeromonas caviae antigens which cross-react with Shigella boydii 5.
Live and boiled cells of 16 strains of Aeromonas caviae, isolated from patients with diarrhea, agglutinated with Shigella boydii 5 antiserum in a slide test. Further studies with seven selected strains showed agglutination with boiled cells in a tube test. Lipopolysaccharide antigen extracted from one of these strains cross-reacted with S. boydii 5 in enzyme-linked immunosorbent assay and immunoblot studies. Either all or the majority of the seven strains possessed properties deemed to be diarrheagenic.
Aeromonas↗
Human autoantibody binding to multiple conformations of DNA.
Systemic lupus erythematosus and rheumatoid arthritis in humans are characterized by circulating and tissue fixed autoantibodies reactive with self antigens including nucleic acids and other nuclear components. Native calf thymus DNA (B-form), DNA.RNA hybrid (A-form), and left handed DNA (Z-form) were reactive with autoantibodies derived from SLE sera. Inhibition studies suggest that antibodies are recognizing multiple conformations presented by altogether different polymers and A- or Z-DNA might be the immunogenic stimulus for the production of antibodies cross reactive with native DNA.
Antibodies, Antinuclear↗
Primary malignant lymphoma of the gastro-intestinal tract: a clinicopathological study of 24 cases.
Twenty-four cases of primary lymphoma of the gastro-intestinal tract were diagnosed during the period 1970 to 1991. There was a preponderance of males and the male to female ratio being 1.4:1. Age ranged from 9-70 years, mean 32.2 years. Small intestine was involved in 50% cases, large bowel in 9 cases (37.5%) and stomach in 3 cases (12.5%). There were 5 cases (20.8%) of Hodgkin's disease and 19 cases (79.2%) were of non-Hodgkin's lymphoma. All cases of gastric lymphoma complained of epigastric pain, weight loss and vomiting. In lymphoma of small intestine, 8 patients complained of pain associated with vomiting and 6 patients complained of distension of abdomen. In large bowel lymphoma, pain in right iliac fossa was complained by 4 patients and bleeding per rectum by 3 patients. Out of all the 24 cases, changes in bowel habit were noted in 15 patients and occult blood was positive in 13 cases. Palpable abdominal mass was noted in 14 patients. Histomorphologically, all the 3 cases in the stomach were of lymphocytic lymphoma diffuse type. Out of 19 non-Hodgkin's lymphoma, 15 were of lymphocytic lymphoma and 4 were of histiocytic lymphoma.
Adolescent↗