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Biomedical subjects

W H Mosley

Publications and source records attributed to W H Mosley.

At least 37 records · Page 2Linked to original sources

Selective destruction of skin permeability activity in cholera toxin: effect of acid on cholera enterotoxin.

The effect of treatment of purified cholera enterotoxin with acid at pH 2.0 for 1 h followed by neutralization of the acid on the biological activity of the toxin has been studied. It was found that the material loses 85 to 96% of its skin permeability activity and this loss is neither reversed nor increased after 28 days of storage at 5 to 10 C. Other biological properties such as diarrheagenic activity, lipolysis-stimulating activity, and the lethal dose for mice remain unaffected by acid treatment. These observations indicate that the skin permeability activity is more sensitive to relatively minor changes in molecular structure than are the diarrheal, lipolytic, and mouse lethality activities.

Acids↗

Field trials of monovalent Ogawa and Inaba cholera vaccines in rural Bangladesh--three years of observation.

A controlled cholera vaccine field trial was carried out to test the efficacy of monovalent whole-cell Inaba and Ogawa cholera vaccines and a purified Inaba antigen. This study was designed particularly to study the level of protection produced by these vaccines against homologous and heterologous serotypes and to correlate the results with mouse protection tests and human serological response to the vaccines. A cohort of 45 000 children, aged 0-14 years, was divided into a control group and three vaccine groups. Inoculations were given annually for 2 years just before the start of the cholera season, and follow-up was continued for one additional year. Essentially, all cholera cases were due to the Inaba serotype, so that protection could be studied only against that serotype. Two annual injections of the whole-cell Inaba vaccine gave the highest level of protection, averaging 84% over the 3 years of follow-up; a single injection of the purified Inaba vaccine gave less protection (51%). Two annual injections of the whole-cell Ogawa vaccine failed to protect children under the age of 5 but did produce 48% protection for children aged 5-14 against Inaba cholera. Serological surveys correlated poorly with protection; specifically, the Ogawa vaccine produced high anti-Inaba titres in young children but no protection. The cross-protection against Inaba cholera produced by Ogawa vaccine in the older children is assumed to be due to boosting of naturally acquired immunity in this population. Monovalent vaccine cannot be recommended for general public health use because of the serotype specificity of protection that this study has demonstrated.

Adolescent↗

[Asian cholera].

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Africa↗

Report of the 1966-67 cholera vaccine trial in rural East Pakistan.

A controlled cholera vaccine field trial was carried out in rural East Pakistan to determine the efficacy of a cholera vaccine of average antigenic potency when used in a continuing programme with annual reimmunizations. A cohort of 40 000 children aged 0-14 years was equally divided into a control group and 3 vaccine groups. Inoculations of vaccine were given annually for 3 years just before the start of the cholera season, and follow-up continued for 2 additional years. The results indicate that there was increasing protection with reimmunization, reaching a maximum with 3 doses. One dose produced 43% protection, 2 doses 64%, 3 doses 81%, and 4 doses 76%. Protection was more sustained after reimmunization; being 50% and 39%, 1 and 2 years after the fourth injection, respectively. Serological surveys suggested a general parallel in the antibody response to vaccine and the level of protection achieved; however, the levels of vibriocidal antibody titres could not be related directly to levels of protection. The overall protection achieved with the 3-year programme of annual reimmunizations was 55% for the group receiving one inoculation annually, and 65% for the group receiving 2 inoculations in the first year followed by annual reimmunizations. When the costs and effectiveness of annual vaccine programmes are compared with those for cholera treatment centres, it becomes clear that the cholera vaccines now available are not appropriate alternatives to treatment in routine cholera control programmes.

Adolescent↗

A comparison of purging and multiple rectal swabs in the detection of inapparent cholera infections.

The relative effectiveness of daily rectal-swab cultures and cultures of purged stools in detecting inapparent infections of Vibrio cholerae were compared in family contacts of cholera patients. In one study of 187 contacts, a combination of purging by various methods plus 5 daily swabs detected 50 infections. Only 27 (54%) were detected by the purge alone, while 47 (94%) were detected by 5 daily rectal-swab cultures. In a second study of two groups of family contacts, purging on the first day did not appear to influence significantly the number of positive rectal-swab cultures obtained during the 4 subsequent days. The relative inefficiency of purging in detecting the inapparent infections among cholera contacts, as compared with its reported efficacy in the chronic convalescent carrier, probably reflects a basic difference in the pathogenesis and site of infection in these different conditions.

Adolescent↗