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Biomedical subjects

G L Barnes

Publications and source records attributed to G L Barnes.

At least 91 records · Page 5Linked to original sources

Complement-fixing antibody response to rotavirus infection.

A human rotavirus complement-fixing (CF) antigen, prepared by purification of large volumes of fluid feces collected from children with winter diarrhea, was used to study the development and persistence of antibody in children with diarrhea and the prevalence of rotavirus antibody in Melbourne. In children with diarrhea, antibody rises were detectable within 4 to 6 weeks of the onset of illness, and the titers usually remained elevated for the next 1 to 2 years. CF antibody did not develop in two children with proven rotavirus infection aged less than 6 months, an age at which poor CF responses to other viruses have also been observed. A study of CF antibody levels in the general community showed that in Melbourne, most children have been infected with human rotavirus by the age of 3 years.

Age Factors↗

Is lactase the receptor and uncoating enzyme for infantile enteritis (rota) viruses?

Rotaviruses are now regarded as important causes of diarrhoea in man, cattle, pigs, mice, and possibly other animals. Characteristically, disease occurs in newborn and young animals, and infection seems limited to the differentiated gut epithelial cells. The major surface polypeptide of the calf scours rotavirus is glycosylated, and highly purified beta-galactosidase (lactase) interacts with the virus in vitro causing removal of the outer shell of the capsid (uncoating). It is suggested that lactase present in the brush border of the intestinal epithelial cell performs a similar function in vivo by acting as a combined receptor and uncoating enzyme for the rotavirus. This hypothesis is consistent with the observations that rotaviruses seem to infect only gut epithelial cells, and that infant animals, whose lactase concentrations are generally higher than those of adult animals, seem more susceptible to rotavirus infections. Implications of the hypothesis include possible new approaches to laboratory cultivation of rotaviruses, which should be more successful in cells selected for surface lactase activity, and the suggestion that the epidemiology of human rotavirus infections may be influenced by the fact that different ethnic groups have different lactase levels (and hence lactose intolerance) in adulthood.

Acute Disease↗

Duodenal biopsy in 75 New Zealand children.

During the past two years, duodenal biopsy has been used freely in a study of diarrhoea and failure to thrive in South Island children. The technique has proved convenient, safe and diagnostically helpful in a high proportion of cases. It has meant that hospital admission has rarely been required. Parents have appreciated the rapid and definite answers, either positive or negative, which have resulted in more rational treatment for their children.

Adolescent↗

Management of sugar intolerance in children.

Sugar intolerance is a common problem in paediatric practice. The usual type is lactose intolerance following gastroenteritis, but it may also occur in a wide variety of disorders of the small bowel. Diagnosis depends upon identification of reducing substances in the stools. An approach to dietary management of lactose intolerance is given and use of a carbohydrate-free formula in secondary monosaccharide intolerance is described. In each situation, threshold for digestion or absorbtion of carbohydrate is approached gradually from below, and overflow detected by Clinitest stool testing.

Carbohydrate Metabolism↗

The aetiology of diarrhoea in newborn infants.

Diarrhoea is a common problem in newborn infants in hospital nurseries. In the past, sporadic diarrhoea was often attributed to dietary indiscretion by the mother, and epidemic diarrhoea was though to be caused by an unknown infectious agent. Techniques with which to locate non-cultivable viruses and untypable enteropathogenic strains of Escherichia coli allow reevaluation of the aetiology of diarrhoea in newborn infants. Preliminary results from Melbourne, Australia, suggest that most diarrhoea in newborn infants is induced by a specific infectious agent. During 1975 the agent most often identified from sporadic and epidemic diarrhoea in hospital nurseries was a reovirus-like particle ("duovirus"). Enterotoxin-producing strains of E. coli were rarely isolated. Future attempts to protect newborn infants from developing diarrhoea must be based on an accurate understanding of the aetiology of this disease.

Australia↗