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Biomedical subjects

M J Albert

Publications and source records attributed to M J Albert.

At least 145 records · Page 8Linked to original sources
PubMed1994

Production of slime polysaccharides by Shigella dysenteriae type 1.

Electron microscopy of ruthenium red-stained ultrathin section of strains of Shigella dysenteriae type 1 grown in the Casamino Acids-yeast extract broth medium showed the presence of an extracellular slime layer. The slime appeared as a dense sheath covering bacteria. The presence of slime promoted hemagglutinating activity of the bacteria. The slime polysaccharide (SPS) isolated from the cell-free culture supernatant or the bacterial surface was less than 162,000 daltons in size and immunochemically similar. The SPS showed cross-reaction with lipopolysaccharide (LPS) antigen in immunological tests; however, it also appeared to be different from LPS since it did not contain 2-keto-3-deoxyoctonate, a core sugar of LPS. A different pattern of separation from LPS was also observed by silver staining of SDS-polyacrylamide gels. From these data it appeared that either LPS and SPS are contaminated with each other or that SPS is the polysaccharide portion of LPS.

Animals↗
PubMed1994

Pili of a Vibrio cholerae O139.

The pili of a strain of Vibrio cholerae O139 were purified and characterized. They were morphologically, electrophoretically and immunologically indistinguishable from the pili with 16 kDa subunit protein of V. cholerae O1. All 22 strains of V. cholerae O139 examined possessed the pili. The pili were different in hemagglutination inhibition pattern from V. cholerae O1 16K pili.

Bacterial Proteins↗
PubMed1994

Isolation of Vibrio cholerae O139 synonym Bengal from the aquatic environment in Bangladesh: implications for disease transmission.

Currently, Bangladesh is experiencing an epidemic of acute watery diarrhea caused by Vibrio cholerae O139. Surface waters were collected and cultured for vibrious following enrichment. Twelve percent (11 of 92) of samples yielded V. cholerae O139, and all of them were positive for cholera toxin. The data suggest that V. cholerae O139 is easily culturable from surface water samples.

Bangladesh↗
PubMed1994

Production, characterization, and application of monoclonal antibodies to Vibrio cholerae O139 synonym Bengal.

Mouse monoclonal antibodies (MAbs) were derived against acetone-treated whole cells of the newly recognized Vibrio cholerae O139 serogroup which is causing epidemics of cholera-like disease in India and Bangladesh. Four MAbs specifically recognized the lipopolysaccharide antigens of V. cholerae O139. MAbs ICL9 and ICL13 were of the immunoglobulin M (IgM) isotype, ICL11 was of the IgG3 isotype, and ICL12 was of the Ig2b isotype. A fifth MAb, ICL10, of the IgG2b isotype cross-reacted with V. cholerae O91. All five MAbs recognized V. cholerae O139 in an enzyme-linked immunosorbent assay, slide agglutination test, motility inhibition test, and indirect immunofluorescence test. During a 1-month evaluation of these MAbs in our clinical laboratory, all 86 cases diagnosed as V. cholerae O139 by a rabbit polyclonal antiserum were also detected by these MAbs, establishing their utility as highly sensitive and specific diagnostic reagents. With these MAbs, it should now be possible to screen for the V. cholerae O139 serogroup in epidemic and endemic diarrhea cases and in environmental and food samples.

Agglutination Tests↗
PubMed1994

Vibrio cholerae O139 synonym bengal is closely related to Vibrio cholerae El Tor but has important differences.

Although Vibrio cholerae O139 synonym Bengal strains, from the current epidemics in India and Bangladesh, are closely related to seventh-pandemic strains, as shown by multilocus enzyme electrophoresis, Bengal strains are encapsulated and portions of the O1 antigen biosynthetic complex genes found in O1 strains are altered or lacking. Encapsulated Bengal strains showed resistance to killing by normal human serum. The presence of the capsule suggests the potential for bloodstream invasion in susceptible hosts and has profound implications for vaccine development.

Animals↗
PubMed1994

Hemagglutinating properties of enteroaggregative Escherichia coli.

Many intestinal bacterial pathogens possess hemagglutinating properties, which are indicative of their adhesive properties to the intestinal mucosal surface. To understand the bacteria-mucosa interaction, 41 strains of enteroaggregative Escherichia coli (EAggEC), a recently described category of diarrheagenic E. coli, isolated mostly from children with diarrhea in Bangladesh, India, Thailand, Central America, and South America were screened for mannose-sensitive hemagglutination and mannose-resistant hemagglutination of erythrocytes from humans, rats, mice, sheep, cattle, and rabbits. Some strains demonstrated mannose-sensitive hemagglutination of erythrocytes. Most isolates showed mannose-resistant hemagglutination of erythrocytes from all species except rabbits. The hemagglutination patterns could be classified into 18 groups. Studies with three selected isolates suggested that hemagglutinins are cell bound and are protein in nature. On the basis of the pattern of inhibition of hemagglutination by various chemicals, 39 isolates were classified into 19 groups. Hemagglutinations of many isolates were inhibited by sialic acid-containing compounds, suggesting that these compounds may be the receptors for these organisms on erythrocytes and possibly on the intestinal mucosa. These data indicate that strains of EAggEC are a heterogeneous group of organisms with different types of hemagglutinins or adhesins for the intestinal mucosal surface. Also, the adhesion characteristics of EAggEC strains may be too complex to be assessed by simple hemagglutination tests.

Adhesins, Escherichia coli↗
PubMed1994

Molecular analysis of rRNA and cholera toxin genes carried by the new epidemic strain of toxigenic Vibrio cholerae O139 synonym Bengal.

Vibrio cholerae O139 synonym Bengal recently caused large epidemics of cholera-like disease in Bangladesh and India. We compared the restriction fragment length polymorphisms of ctxA and rRNA genes (ribotypes) in 27 isolates of V. cholerae O139 from patients in Bangladesh and India with those of 48 isolates of V. cholerae O1 from patients and 21 V. cholerae isolates from surface waters in Bangladesh, which included 2 O139 and 19 other non-O1 isolates. Ribotyping of the isolates with BglI revealed that all 29 isolates of O139 vibrios belonged to a single ribotype, suggesting a clonal nature of the infection. However, the O139 vibrios comprised two ctxA genotypes and carried three or more copies of the ctxA gene, and the chromosomal locations of these copies were unlike those of the El Tor or classical vibrios. Analysis of the restriction fragment length polymorphisms of the rRNA genes suggested that V. cholerae O139 isolates are more closely related to El Tor strains of V. cholerae O1 than were 19 other non-O1 vibrios and 33 classical V. cholerae O1 isolates that were studied. However, further studies are needed to determine whether V. cholerae O139 originated from mutations and genetic changes in a V. cholerae O1 strain or was due to the acquisition of virulence genes by a previously unknown V. cholerae non-O1 strain.

Bacterial Typing Techniques↗
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

Development and evaluation of rapid monoclonal antibody-based coagglutination test for direct detection of Vibrio cholerae O139 synonym Bengal in stool samples.

A monoclonal antibody-based coagglutination test directly detected Vibrio cholerae O139 synonym Bengal in 83 of 120 watery diarrheal stool specimens; on culture, 90 samples were positive. Thus, with 92% sensitivity, 100% specificity, and 100% positive and 95% negative predictive values, the coagglutination test is a useful rapid test for V. cholerae O139.

Agglutination Tests↗
PubMed1994

Hafnia alvei in stool specimens from patients with diarrhea and healthy controls.

We found an epidemiological association of Hafnia alvei with diarrhea, because the organism was isolated from 12 of 77 (16%) adult Finnish tourists to Morocco who developed diarrhea and from 0 of 321 tourists without diarrhea (P < 0.001). From another group of 112 adult Finnish diarrheal patients, only 2 (2%) yielded H. alvei. In contrast to some Bangladeshi strains of H. alvei, the Finnish strains were negative for the attachment-effacement lesion by an in vitro fluorescent acting staining test and also did not show homology to the Escherichia coli attachment-effacement gene (eaeA) by PCR. These results suggest that a mechanism or mechanisms other than the attachment-effacement lesion may also be involved in the association of H. alvei with diarrhea.

Actins↗
PubMed1994

Tibial plateau fractures: evaluation with MR imaging.

Thirty patients with 31 tibial plateau fractures, initially diagnosed with standard radiography, were further studied with biplane linear tomography and magnetic resonance (MR) imaging. Each fracture was categorized according to the Schatzker classification. The extent of comminution and articular depression was determined for each modality. MR images were also evaluated for the presence of accompanying meniscal and ligamentous injury. In each case, MR imaging was noted to be as effective as tomography in depicting the amount of articular depression. MR imaging was found to be more effective than tomography in determining the extent of comminution. Beyond demonstrating the fracture, MR imaging was capable of revealing associated ligamentous and meniscal injuries. There was an increased prevalence of accompanying soft-tissue injuries in those fracture types that are associated with more violent forces and as the extent of articular depression increased. MR imaging is a useful and effective means of preoperatively evaluating tibial plateau fractures.

Adult↗
PubMed1994

Distribution of Zonula occludens toxin (zot) gene among clinical isolates of Vibrio cholerae O1 from Bangladesh and Africa.

Seventy-two clinical isolates of Vibrio cholerae O1 from Bangladesh, and 12 and 9 isolates respectively from Tanzania and Nigeria were screened for sequences homologous to zonula occludens toxin (zot) and cholera toxin (ctx) genes. As observed previously, all isolates in the present study also possessed sequences for both toxins which suggested that zot does not occur independent of ctx. It appears that along with the virulence genes located in the "virulence cassette" region of the bacterial chromosome, zot may play a role in the pathogenesis of cholera.

Africa↗
PubMed1994

Evaluation of a non-radioactive chemiluminescent method for using oligonucleotide and polynucleotide probes to identify enterotoxigenic Escherichia coli.

We compared the applicability of an enhanced chemiluminescent (ECL) method for using gene probes with that of radioactive probes to identify enterotoxigenic Escherichia coli (ETEC) in stools of Bangladeshi children with diarrhoea. Colony blots of E. coli isolates were hybridized using both [alpha-32P]-dCTP labelled and fluorescein-11-dUTP labelled polynucleotide and oligonucleotide gene probes for heat-labile enterotoxin (LT), and heat-stable enterotoxin (ST). Analysis of 1,620 isolates obtained from 540 patients gave similar results by both radioactive and chemiluminescent probes. The ECL method was faster than the radioactive method. Both polynucleotide and oligonucleotide probes could be used by the ECL method. Hybridization and detection by the ECL method appeared to be a convenient alternative to radioactive probes for screening E. coli isolates for ETEC.

Base Sequence↗
PubMed1994

Shigella carriers among non-diarrhoeal children in an endemic area of shigellosis in Bangladesh.

Shigellosis is endemic in Bangladesh and other developing countries. Asymptomatic carriers have been incriminated in the maintenance and spread of the disease in the community. To study the incidence of the asymptomatic carrier state of Shigella, we conducted surveys in two groups of children under 5 years of age. The first group consisted of 249 ill children who did not have diarrhoea, and the second group consisted of 699 apparently healthy children. The Shigella carrier rate in the first group was 6.4% and that in the second group 2.1%. These carriers may be important in maintaining the transmission of Shigella organisms in the community.

Bangladesh↗