Search PubMed⌕ Search

Biomedical subjects

A Hossain

Publications and source records attributed to A Hossain.

At least 73 records · Page 4Linked to original sources
PubMed1993

Differential induction of c-jun expression by PGF2-alpha in rat ovary, uterus and adrenal.

The influence of PGF2 alpha on c-jun gene expression in ovary, uterus and adrenal was examined. Three and seven day postovulatory PMSG primed immature rats received 500 ug PGF2 alpha by two subcutaneous injections 8 hours apart. Control rats received saline. Animals were sacrificed 30 minutes after the second injection of PGF2 alpha. Tissues were obtained and frozen in liquid nitrogen. RNA extracted from ovary, uterus and adrenal was analyzed by Northern and slot blot. c-jun was expressed differentially in these organs. An increase in c-jun expression by PGF2 alpha treatment occurred in the ovary but not in the adrenal and uterus. The effect of PGF2 alpha on c-jun was stronger in older compared to younger corpora lutea. These results indicate differential regulation of c-jun by PGF2 alpha in steroidogenic and steroid responsive tissues and that c-jun might be linked to the mode of action of PGF2 alpha in luteolysis.

Adrenal Glands↗
PubMed1993

Characterisation of Plesiomonas shigelloides strains that share type-specific antigen with Shigella flexneri 6 and common group 1 antigen with Shigella flexneri spp. and Shigella dysenteriae 1.

Three strains of Plesiomonas shigelloides isolated from patients with diarrhoea were agglutinated with Shigella flexneri 6 antiserum in slide and tube tests. All the strains were also agglutinated with a monoclonal antibody to the common group 1 antigen shared between S. flexneri serotypes and S. dysenteriae type 1. Further studies with one strain also showed sharing of antigenicity in an enzyme-linked immunosorbent assay. The results suggest that the strains share type-specific antigen with S. flexneri 6 and the common group 1 antigen with S. flexneri serotypes and S. dysenteriae 1. The sharing of antigens may have implications for cross-protection. One strain adhered to HEp-2 cell monolayers. None of the strains contained high mol. wt plasmids and there was no sequence homology with the invasiveness plasmid of Shigella spp. in DNA probe hybridisation. They were susceptible to the commonly used antibiotics. However, they possessed four other virulence-associated properties of Shigella spp. that included Congo-red binding, hydrophobicity, toxicity to HeLa cells and HEp-2 cell invasiveness (although they gave negative results in the Sereny test for invasiveness). These data suggest that the three unique strains might be considered pathogenic. Studies in animal models and human volunteers would be necessary to establish their pathogenic potential.

Agglutination Tests↗
PubMed1993

Heat-labile and heat-stable haemolysins of Campylobacter jejuni.

During studies on the virulence mechanisms of Campylobacter jejuni clinical isolates it became apparent that some strains produced one or more haemolysins and some did not. There was no great difference between Group C (cholera-like) strains and Group D (dysentery-like) strains. The protein haemolysin(s) showed a spectrum of activity against erythrocytes from different animals; with maximum activity against rabbit and minimal activity against chicken erythrocytes. The results suggested a two-stage activation mechanism for haemolysis which involved a multi-hit lytic activity. It was concluded that the C. jejuni haemolysins were not identical to those described in other organisms and they may be involved in iron acquisition in vivo.

Animals↗
PubMed1993

Evaluation of a probe hybridisation serotyping method for group A rotavirus.

Serotype-specificity and sensitivity of oligonucleotide probes to serotype human rotaviruses was assessed. Probes could detect as little as 6.3 ng of homologous RNA and none reacted with as much as 100 ng of heterologous RNA. Northern-blot analysis revealed that probes reacted with one of genomic segments 7, 8 or 9 of corresponding serotypes.

Diarrhea↗
PubMed1993

Production of mucinase and neuraminidase and binding of Shigella to intestinal mucin.

Production of mucinase and neuraminidase by Shigella spp. and their ability to bind to mucin was investigated. All four species of Shigella produced these enzymes. Virulent and avirulent pairs of Shigella did not differ in their ability to produce the enzymes after 18 h of growth. However, a significant difference in neuraminidase production was noted in Shigella dysenteriae type 1 and S. boydii (12-15) at 10 h growth. Avirulent strains of S. dysenteriae type 1, S. flexneri 2a, and S. boydii bound significantly more amounts of mucin than their virulent counterparts.

Animals↗
PubMed1992

Enteropathogens associated with acute and persistent diarrhea in Bangladeshi children less than 5 years of age.

A longitudinal study of diarrhea was carried out from May 1988 to April 1989 by household surveillance of 705 children less than 5 years old in rural Bangladesh. Stool samples were examined for enteric pathogens at the beginning of each diarrheal episode. For persistent episodes, stool examination was repeated on days 15-17 of the illness. For each case of persistent diarrhea, stool samples from age-matched acute diarrheal and healthy controls were examined. Compared with healthy controls, cases of diarrhea were associated with Shigella species (P = .07) and rotavirus (P less than .05). Diffusely adherent Escherichia coli (P less than .05) and cryptosporidia (P = .07) were the only enteropathogens associated with persistent diarrhea in comparison with acute diarrhea. No more than 15% of children had the same class of pathogen identified from stool on both days 1-3 and days 15-17, indicating that persistent infection was uncommon. However, a different enteropathogen was frequently found on days 15-17, suggesting that sequential infection may be a cause of persistent diarrhea.

Bangladesh↗
PubMed1992

Lipopolysaccharide composition and virulence properties of clinical and environmental strains of Vibrio fluvialis and Vibrio mimicus.

Vibrio mimicus strains W-26768 (stool isolate) and N-1301 (environmental isolate) and Vibrio fluvialis strains AA-18239 (stool isolate) and M-940 (environmental isolate) were studied for virulence properties and lipopolysaccharide composition. All four strains were hydrophobic, produced cytotoxin, adhered to HeLa cells and showed mannose-sensitive agglutination of guinea pig erythrocyte. The strains were negative for enterotoxin production and were mostly susceptible to the common antibiotics. The environmental and clinical isolates of both species were antigenically unrelated to each other. Lipopolysaccharide antigen analysis showed that O-antigen polysaccharides of two strains of V. fluvialis and two strains of V. mimicus differed with respect to the sugar components. Only LPS from V. mimicus W-26768 showed the presence of an unusual sugar, 3,6-dideoxy-3-acetamido-hexose. The sugar compositions of these V. fluvialis and V. mimicus strains differed from those of previously reported Japanese isolates. These differences probably reflect differences in the serogroup of strains.

Anti-Bacterial Agents↗
PubMed1992

Comparison of a modified adherence assay with existing assay methods for identification of enteroaggregative Escherichia coli.

Localized, diffuse, and aggregative adherence patterns of Escherichia coli identified with specific DNA probes were compared in cell culture adherence assays by using the Center for Vaccine Development, Baltimore, method, the University of Texas Medical School, Houston (UTH), method, and a modified UTH method. Increasing postwash incubation time from 2 to 4 h in the modified UTH method allowed identification of enteroaggregative E. coli, which was otherwise not identified by the original UTH method.

Bacterial Adhesion↗
PubMed1991

Contact-haemolysin production by entero-invasive Escherichia coli and shigellae.

Entero-invasive Escherichia coli (EIEC) and shigellae were tested for contact-haemolysin (CH) with red blood cells (RBCs) of guinea-pig, rabbit, rat, mouse, monkey, man, sheep and chicken; all bacteria showed the best lysis with guinea-pig RBCs. The best culture medium for CH activity of shigellae was tryptic soy broth, and for EIEC it was casamino acid-yeast extract broth with 1 mM CaCl2. CH production by all species was best at the slightly alkaline pH which is optimal for growth; it was also dependent on the presence of a large (140-Mda) plasmid. Pre-treatment of bacteria with homologous antisera inhibited CH activity. Various treatments of bacterial cells and RBCs suggested that CH may be a protein molecule, and that a chitotriose-like moiety may serve as CH receptor. RBCs that were incubated with bacteria at 4 degrees C, or with heat-killed bacteria at 37 degrees C, were not lysed; also, isolated cell-surface components (lipopolysaccharide and outer-membrane protein) did not lyse RBCs. This suggests that metabolically active cells are required for CH activity. Production of CH by both EIEC and shigellae is consistent with a common mechanism for the virulence of these organisms.

Animals↗
PubMed1991

A spider toxin binding protein from bovine brain: its purification and N-terminal amino acid sequence determination.

A 60kDa spider toxin binding protein from bovine brain was solubilized with digitonin and purified up to 5800-folds over starting crude homogenate. The purification procedure entailed DEAE-cellulose, concanavalin-A affinity, 1-naphthylacetyl spermine affinity and high performance liquid chromatography. The purified protein owned a very high affinity for ligand 125I-JSTX-3 binding Kd 15.6nM and Bmax 6.5nM. The amino acid composition of the protein was determined. The N-terminal amino acid sequence analysis yielded a unique sequence: NH2-X-Pro-X-Val-Tyr-Phe-Lys-Glu-Gln-Phe-Leu-Asp-Gly-Asp-X.

Amino Acid Sequence↗
PubMed1991

Environmental health in primary schools in a developing country.

In an effort to elucidate the environmental health in developing countries, the environmental and sanitary conditions of Riyadh primary schools were assessed by use of a scoring evaluation sheet for 20 schools representative of primary schools of Riyadh. 20% of schools have been found to be ideally situated and only one fourth of schools with proper building. As regards class rooms, only 25% of them have adequate floor area, window area and are suitably illuminated. Drinking fountains per pupil were inadequate. Overall, environmental rating of 10% excellent, 30% good, and 60% bad were detected in present study. The bad situation of almost two-thirds of primary school buildings in Riyadh is alarming. Remedial suggestion have been forwarded.

Child↗
PubMed1991

Seroepidemiology of enteric fever and brucellosis in a developing country.

The seroepidemiology of infection due to S. typhi and Brucella spp. in a sub-tropical, developing country of the Middle East was investigated in 130 children of age less than 1 to 15 years, 117 young adults (16-30 years) and in a further 40 adults (greater than 30 years) using an agglutination test to detect antibodies to of S. typhi, B. abortus and B. melitensis. Only 4.5% of the children's and adult's sera respectively showed the presence of antibodies to both O and H antigens of S. typhi with reciprocal titers greater than or equal to 80. Prevalence rates of 11.6%, 11.3% respectively in children and adults of antibodies to B. abortus with reciprocal titers greater than or equal to 80 and similarly 13.1%, 12.4% to B. melitensis were found. The usefulness of a single Widal test to diagnose enteric fever in a non-endemic area and the agglutination test in the diagnosis of brucellosis in an endemic area was investigated. Of 244 patients with suspected enteric fever, the sera of 100 showed reciprocal antibody titers 80 to both O and H antigens and included in these were 8 patients with concurrent culture positivity. Among 138 children and adults with suspected brucellosis, 29 culture proven cases where serologically confirmed and a further 90 were detected serologically. The sera of all the culture proven cases exhibited antibody reciprocal titer greater than or equal to 640. A similar antibody response was noted in seventy-two of the culture negative cases diagnosed serologically for brucellosis. In culture proven, cases B. melitensis was the isolate. Comparative evaluation indicated the potential usefulness of the Rose Bengal Antigen Slide Agglutination Test (Brucelloside Test) as a screening test in the serodiagnosis of human brucellosis.

Adolescent↗
PubMed1990

Chlamydia trachomatis as a cause of abortion.

The possible role of C. trachomatis as a causative agent of abortion in humans was investigated using the tissue culture method for the isolation of chlamydia. Two cases of spontaneous abortion and another seven of recurrent abortion due to C. trachomatis were positively identified. Among those with recurrent abortion were four patients with history of second trimester abortion.

Abortion, Spontaneous↗
PubMed1989

Genital herpes simplex virus infections: laboratory confirmation in diverse patient groups.

The laboratory diagnosis of genital herpes simplex virus (HSV) infections in various patient groups with diverse clinical manifestations including asymptomatic pregnant women with history of genital herpes and in a high prevalence group consisting of male patients with recurring genital ulcerations is described. HSV was detected by conventional cell culture and also by a CPE-enhancement technique using human embryonic lung fibroblasts (MRC-5) and Vero cells with subsequent typing of isolate by HSV type-specific monoclonal antibodies. A definite improvement in HSV diagnosis was noted by the use of the CPE-enhancement technique with the reduction of turn-around time to 24 h at which 61.1% and 50% isolation rates were detected in MRC-5 cells in comparison to 38.9% and 16.6% by conventional cell culture in the high prevalence patient population and asymptomatic pregnant women, respectively. Delayed development of CPE and reduced isolation rates were detected using Vero cells. Follow-up sampling of subsequent episodes of genital ulcerations in those with history of recurrence but an initial negative cell culture result, increased the isolation rate substantially and enabled the confirmation of diagnosis of genital HSV infection.

Cells, Cultured↗
PubMed1989

Chlamydia trachomatis infections.

The diversity in chlamydial syndromes and their consequences especially the impact on human reproduction and fertility, the asymptomatic characteristics of infections and the ever-increasing incidence have been the focus of considerable attention in the 1980s. The current status of the clinical spectrum of ocular-genital infections due to Chlamydia trachomatis and the laboratory tests for accurate, rapid diagnosis and effective treatment are reviewed.

Anti-Bacterial Agents↗
PubMed1989

Acute lower respiratory infections: a major cause of death in children in Bangladesh.

The importance of acute lower respiratory infections (ALRI) as a cause of death in children was estimated using systematically collected demographic data on the population of the Teknaf area of southern Bangladesh. Of 1349 children aged 1-59 months who died between 1 January 1982 and 31 December 1985, ALRI was diagnosed by verbal autopsy in 390 (29%) and was the leading cause of death. ALRI mortality rates were highest in the youngest age groups (136/1000 for those less than or equal to 5 months) and decreased in older children (16/1000 for those 3-4 years old). Half of all fatal ALRI cases occurred in children less than 6 months old. In older children, ALRI-associated deaths tended to occur during the months October to January, while deaths in infants tended to follow the seasonal birth pattern. Significant predisposing factors for fatal ALRI were malnutrition and measles, detected, respectively, in 18% and 8% of children who died from ALRI. This study emphasizes the importance of ALRI as a major cause of death in developing countries and suggests that interventions to reduce childhood mortality are needed and should be targeted to specific age groups at risk.

Acute Disease↗
PubMed1989

Infectious mononucleosis and mononucleosis-like illnesses in children and adults in Saudi Arabia.

The diagnosis of heterophil antibody positive, heterophil negative infectious mononucleosis and mononucleosis-like illnesses as made in 58 children and adult patients with clinical features suggestive of the mononucleosis syndrome and significant number of atypical lymphocytes. Epstein-Barr virus (EBV) specific serological tests revealed that six children and 23 adults had primary heterophil positive EBV infections based on the detection of IgM to EB-viral capsid antigens (IgM-VCA), presence of IgG to DB-early antigens (EA-D) and absence of antibodies to EB-nuclear antigen (EBNA). A further nine cases (five children, four in adults) of heterophil negative EBV infectious mononucleosis were likewise detected by EBV-specific serologic tests. Fourteen cases including one in children were due to active cytomegalovirus (CMV) infections as evident by positive CMV-IgM; they were all heterophil negative. Of the remaining heterophil negative cases, one was due to T. gondii with positive Toxo-IgM and five cases were of undetermined aetiology.

Adolescent↗