Adherence and invasion studies were conducted in monolayers of Caco-2 cells. Three-day-old monolayers were inoculated with Campylobacter jejuni 81-176 at a bacterium/cell ratio of 1,000:1. Saturation studies demonstrated time- and dose-dependent saturation curves for C. jejuni cell association and invasion into Caco-2 cells. Electron microscopy revealed intracellular C. jejuni located within membrane-bound vacuoles. Cell association and invasion were inhibited by 0.3 and 0.5 M concentrations of various sugars, including D-glucose, D-mannose, and D-fucose. However, there was no inhibition with the corresponding L-sugars, indicating physiological specificity. The inhibition of cell association with phloridzin was less pronounced. There was no inhibition of bacterial entry with monodansylcadaverine or g-strophanthin, indicating that it was unlikely that coated-pit formation is important in the invasion of C. jejuni into Caco-2 cells. Furthermore, there was no inhibition with cytochalasin D, vincristine, or vinblastine. Inhibition of cell association was demonstrated at 4 degrees C. Significantly decreased cell association and invasion were seen in potassium-depleted cells. Treatment of cells with bromelain also caused reduction in the number of C. jejuni binding to cells. A nonmotile aflagellate variant of C. jejuni also showed reduced invasion. The results of this study are consistent with energy-dependent invasion mechanisms. The results do not support an endocytic method of invasion for C. jejuni into Caco-2 cells.

Campylobacter jejuni↗

PubMed1994

Ribosomal RNA patterns identify additional strains of Campylobacter jejuni and C. coli among isolates serotyped by heat-stable and heat-labile antigens.

Heat-stable (HS, O-antigen) and heat-labile (HL) serotyping are the most common methods used to type Campylobacter jejuni and C. coli for epidemiologic purposes. In this study, we conducted RRNA analysis to differentiate strains of C. jejuni and C. coli that had been serotyped by use of the passive hemagglutination (heat-stable) and slide agglutination (heat-labile) methods. Ribotyping of isolates within HS and HL serotypes revealed further discrimination of strains. Four ribotypes were identified by Pvu II and Pst I digests of eight HS serotype-34 isolates. Ribotyping also differentiated strains within HL serotypes. Ribotyping also was conducted on 10 representative isolates of C. jejuni and C. coli isolated from an infant macaque. The eight ribotypes confirmed previous results of serotyping and other phenotypic analyses, which indicated that the infant was repeatedly reinfected with different strains of C. jejuni and C. coli. Results of the study indicated that ribotyping is a sensitive molecular marker for distinguishing strains of C. jejuni and C. coli. Furthermore, some isolates with similar ribotype patterns had variability in their HS and HL serotypes.

Animals↗

PubMed1993

Early colonic damage and invasion of Campylobacter jejuni in experimentally challenged infant Macaca mulatta.

Experimental challenge studies with Campylobacter jejuni were conducted in 3.5-month-old infant Macaca mulatta. One infant monkey (92-1) was challenged with 2.7 x 10(10) cfu of strain 78-37. A second infant was infected intentionally by natural transmission. The infants developed diarrhea 32 h after challenge of infant 92-1. Electron microscopic observations indicate that cell invasion is the primary mechanism of colon damage and diarrheal disease caused by C. jejuni. Intracellular C. jejuni were located in membrane-bound vacuoles and were free in the cytoplasm. Damaged epithelial cells exhibited premature apoptosis and were exfoliated into the lumen of the colon. C. jejuni were also located extracellularly in the mucosa and submucosa. Some cells had dilated endoplasmic reticulum, indicating possible alteration in ion and water transport.

Animals↗

PubMed1993

Demonstration of lipopolysaccharide with O-polysaccharide chains among different heat-stable serotypes of Campylobacter jejuni by silver staining of polyacrylamide gels.

Lipopolysaccharide (LPS) from three human and four monkey isolates of Campylobacter jejuni was extracted in high yields that revealed ladder-like structures in polyacrylamide gels by direct silver staining. These observations demonstrate that C. jejuni possesses LPS with O-chain repeating units typical of the family Enterobacteriaceae. The isolates showed differences in the number and electrophoretic mobility of bands in silver-stained gels.

Animals↗

PubMed1992

The hospital ethics committee and moral authority.

Explore the source record for details and available documents.

Ethics Committees↗

PubMed1989

Peroxisomal bifunctional enzyme deficiency.

Peroxisomal function was evaluated in a male infant with clinical features of neonatal adrenoleukodystrophy. Very long chain fatty acid levels were elevated in both plasma and fibroblasts, and beta-oxidation of very long chain fatty acids in cultured fibroblasts was significantly impaired. Although the level of the bile acid intermediate trihydroxycoprostanoic acid was slightly elevated in plasma, phytanic acid and L-pipecolic acid levels were normal, as was plasmalogen synthesis in cultured fibroblasts. The latter three parameters distinguish this case from classical neonatal adrenoleukodystrophy. In addition, electron microscopy and catalase subcellular distribution studies revealed that, in contrast to neonatal adrenoleukodystrophy, peroxisomes were present in the patient's tissues. Immunoblot studies of peroxisomal beta-oxidation enzymes revealed that the bifunctional enzyme (enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase) was deficient in postmortem liver samples, whereas acyl-CoA oxidase and the mature form of beta-ketothiolase were present. Density gradient centrifugation of fibroblast homogenates confirmed that intact peroxisomes were present. Immunoblots of fibroblasts peroxisomal fractions showed that they contained acyl-CoA oxidase and beta-ketothiolase, but bifunctional enzyme was not detected. Northern analysis, however, revealed that mRNA coding for the bifunctional enzyme was present in the patient's fibroblasts. These results indicate that the primary biochemical defect in this patient is a deficiency of peroxisomal bifunctional enzyme. It is of interest that the phenotype of this patient resembled neonatal adrenoleukodystrophy and would not have been distinguished from this disorder by clinical study alone.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMedDate not supplied

The hospital ethics committee. Health care's moral conscience or white elephant?

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Bioethical Issues↗

PubMedDate not supplied

State interests in terminating medical treatment.

Judicial reasoning in termination of treatment decisions has neglected valid state interests in the preservation of life and the ethical integrity of medicine. Courts must balance these interests against individual liberty, rather than assuming that patient autonomy is absolute.

Cultural Diversity↗