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Biomedical subjects

R Robins-Browne

Publications and source records attributed to R Robins-Browne.

27 records · Page 2Linked to original sources
PubMed1984

Attachment of E. coli-bearing K88 antigen to equine brush-border membranes.

Equine small intestinal brush-border membranes, from 40 adult horses were tested in vitro for the presence of receptors for the Escherichia coli adhesive antigens K88ab, K88ac and K99. Only K88-positive strains of E. coli adhered strongly to horse brush-border membranes. In contrast, a K88-negative mutant strain J2, 2 K99-positive strains and 3 E. coli strains isolated from foals failed to adhere to horse brush-border membranes. Purified K88ac pili when reacted with equine brush-border membranes inhibited to a great extent the adhesion of K88-positive E. coli. Similarly, K88-positive E. coli previously reacted with K88 antibody, did not attach to equine brush-border membranes. Oral inoculation of 4 newborn foals with strains of K88-positive enterotoxigenic E. coli, producing either heat-stable or heat-labile enterotoxin, caused diarrhoea in 1 animal.

Adhesiveness↗
PubMed1982

Reactogenicity, immunogenicity and efficacy studies of Escherichia coli type 1 somatic pili parenteral vaccine in man.

Purified type 1 somatic pili from enterotoxigenic Escherichia coli (ETEC) strain H10407 (O78:H11) was evaluated as a parenteral immunizing agent in the hope that this antigen might enhance a contemplated polyvalent pilus vaccine. Intramuscular inoculation with 45, 90, 900 or 1 800 mcg of pili vaccine was tolerated without incident in 82 volunteers. Six of 15 persons who received a 28 day booster of 1 800 mcg developed local reactions while none of 52 persons receiving 180 or 450 mcg boosters evinced such reactions. Pili vaccine did not significantly alter intestinal transit time, absorptive capacity or the prevalence of colonic E. coli bearing type 1 somatic pili of the H10407 antigenic variety. All vaccinees developed significant rises in circulating IgG antibody to type 1 somatic pili, the magnitude of the response being directly proportioned to the vaccine dose. None of the vaccinees had significant rises to CFA I or II pili nor to heat-labile enterotoxin. However, many had rises in O antibody, particularly among those inoculated with 1 800 mcg. Three challenge studies were carried out with E. coli H10407 to assess vaccine efficacy. In the initial study the vaccinees were either protected against diarrhea (2 of 6 vaccinees versus 7/7 of controls) or had milder disease than the controls. In two subsequent challenges with H10407 significant protection was not seen. It was not clear whether protection exhibited by the vaccinee group in the first challenge was due to O antibody, pili antibody, or both acting synergistically. To clarify this, a group of the immunized volunteers were challenged with ETEC strain B7A which is a different serotype (O148:H28) lacks CFA/I or II pili, but possesses type 1 somatic pili antigenically distantly related to those of H10407. Attack rates and severity of illness were similar in both vaccinee and control groups. While most volunteers challenged with E. coli H10407 developed significant rises in circulating antibody to CFA/I, LT and O antigen, none had rises to type 1 somatic pili. It is unclear if this is due to immune tolerance to this antigen when encountered enterally or whether these pili are not present in vivo in ETEC initiating diarrhea in the proximal small intestine. In summary, parenterally inoculated type 1 somatic pili were safe and highly immunogenic in man but did not consistently induce protection. Further studies are planned to clarify the role of antibody to type 1 somatic pili in mediating protection.

Adult↗
PubMed1981

Proliferation of enteropathogens in oral rehydration solutions prepared with river water from Honduras and Surinam.

Oral rehydration of infants with diarrhoea is an effective therapy that is becoming increasingly available in developing countries. To formulate judicious recommendations for preparation and storage of such solutions, we assessed the capability of recognized bacterial enteropathogens to survive and proliferate in solutions made either with sterile distilled or river water collected in two developing countries. Shigella flexneri, an enteropathogen typically transmitted by faecal/oral contact rather than by water or food, survived very poorly. In contrast, Vibrio cholerae and enterotoxigenic Escherichia coli, pathogens classically associated with transmission by food and water, reached concentrations of 103-104 per ml by 12 h and 104-106 by 24 h after inoculation of solutions made with river water and somewhat lower concentrations in distilled water. This potential exposure to bacteria must be considered in the context of the field situation where children are already ingesting high levels of bacteria in drinking water and food and where the oral rehydration solution would probably add little to their exposure. Although it is probably wise to prepare solutions fresh each day with water as free from faecal pollution as possible, in situations where lack of fuel to boil water or scarce supply of glucose/electrolyte packets preclude compliance with these recommendations prompt administration of oral rehydration solutions to infants with diarrhoea should nevertheless proceed.

Administration, Oral↗
PubMed1980

Microtiter enzyme-linked immunosorbent assay for immunoglobulin G cholera antitoxin in humans: method and correlation with rabbit skin vascular permeability factor technique.

A microtiter enzyme-linked immunosorbent assay (ELISA) to measure immunoglobulin G cholera antitoxin in human serum has been developed. The ELISA employs commercially available reagents, including cholera enterotoxin and goat anti-human immunoglobulin G. It is specific, sensitive, and reproducible and requires as little as 5 microliter of serum. ELISA, moreover, permits quantitative determination of cholera antitoxin at a single serum dilution of 1:200. A total of 162 pre- and post-challenge sera from 49 volunteers who ingested Vibrio cholerae classical biotype, and 165 sera from 43 volunteers who ingested V. cholerae El Tor biotype, were tested for cholera antitoxin by ELISA and by the rabbit skin vascular permeability factor assay. The correlation between the two assays was statistically significant (P less than 0.001). ELISA for immunoglobulin G cholera antitoxin thus provides a valuable in vitro correlate of in vivo toxin-neutralizing capacity. Microtiter ELISA permits duplicate evaluation of at least 14 sera per 96-well plate including blanks and controls, is readily adapted to use in field studies, and therefore is particularly well suited to seroepidemiological surveys.

Animals↗
PubMed1977

A multicentre study of the susceptibility of a variety of bacteria to cephalothin, cefamandole, tobramycin and gentamicin.

A multicentre study of antibiotic susceptibility was performed in South Africa. Sensitivity to cephalothin, cefamandole, tobramycin and gentamicin was tested on a variety of aerobic and anaerobic bacteria. Two disc susceptibility techniques were used, i.e. the Kirby-Bauer technique (aerobes) and the broth-disc method (anaerobes); minimum inhibitory concentrations (MICs) were determined according to the International Collaborative Study techniques, and regression lines for individual centres were constructed. Satisfactory lines were obtained for cephalosporins, but, in some centres, problems were experienced with the aminoglycosides. Variations in MICs for Haemophilus influenzae were probably due to an inoculum effect. Accumulative percentage tables of the number of strains inhibited were compiled, and the comparative performance of the antibiotics was assessed.

Anti-Bacterial Agents↗