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Biomedical subjects

S H Parry

Publications and source records attributed to S H Parry.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Significance of immune mechanisms in relation to enteric infections of the gastrointestinal tract in animals.

The impact of bacterial colonization on the alimentary tract in early life is reflected in gross changes in morphology. Subsequent health, if not survival, may largely be determined by a continuum of local intestinal immune mechanisms and it is essential for antibody development during the neonatal period to compensate adequately for declining passive maternal antibody. Consequent upon the development of the gut microflora the lamina becomes infiltrated with immunocytes in which the dominant immunoglobulins produced are IgM and IgA. Both immunoglobulins are transported across the epithelium by a process involving membrane-bound vesicles. Germ-free and fistulated pigs and calves are shown to be able to respond to oral immunization with Escherichia coli O somatic antigens during the first week of life. Resistance to infection with enteropathogenic E. coli was significantly enhanced, along with other parameters of nutrition and performance. However, in the young chick, although the intestinal response to infection with E. coli was similar to that in the mammal, no response to E. coli O antigens could be determined on oral administration in germ-free or local intestinal applications in fistulated birds. In the mammalian intestine secretory antibodies participate in the control of pathogenic E. coli by blocking adhesion to the mucosal epithelium, interfering with the elaboration of surface antigens, inhibiting toxins, and facilitating rapid elimination from the alimentary tract by agglutination and bacteriostasis. In consequence fewer enteropathogens are excreted into the environment, an important feature in modern intensive systems of animal production.

Animals↗
PubMedDate not supplied

A comparative study of the mannose-resistant and mannose-sensitive haemagglutinins of Escherichia coli isolated from urinary tract infections.

The distribution of mannose-resistant (MRHA) and mannose-sensitive (MSHA) fimbrial haemagglutinins was examined in 482 strains of Escherichia coli isolated from 390 adult women and 45 pregnant mothers with a variety of urinary tract infections (UTI), and from 47 healthy controls. The proportion of MRHA strains was significantly higher in patients with symptomatic UTI (75%) than in women with non-significant bacteriuria (30%, p less than 0.001), pregnant women with asymptomatic UTI (34%, p less than 0.0001) and healthy controls (0%). The proportion of MSHA strains was significantly lower in patients with symptomatic UTI (22%) than in women with non-significant bacteriuria (46%, p less than 0.001) and pregnant women with asymptomatic UTI (52%, p less than 0.01). Only 17% of the strains from healthy controls had MSHA activity. In pregnant women with UTI, whether this was symptomatic or asymptomatic, there was a significant association between infection with MRHA strains of E. coli and a past history of UTI. Thus, in a pregnant woman with an infection and a past history of UTI there is a seven-fold greater chance that this infection is due to an MRHA-bearing organism than in pregnant women without such a history. There was also a significant association between MRHA organisms and symptomatic infection. The risk of symptomatic patients having an infection with an MRHA strain is six times greater than that for a patient with a covert infection.

Adhesiveness↗