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Biomedical subjects

M G Smith

Publications and source records attributed to M G Smith.

At least 91 records · Page 5Linked to original sources

In vivo transfer of R factors between Escherichia coli strains inoculated into the rumen of sheep.

Substantial transfer of R factors occurred in vivo, under certain conditions, in the rumen of adult sheep in the absence of any antibiotic treatment. A starvation period of 24-48 hr. was required to produce the conditions necessary, when even quite low inocula (ca. 10(3) cells) of donor and recipient E. coli could grow within the rumen and reach a population density sufficient for transfer to take place. The results indicate that under the same conditions R factors may be transferred between organisms in the lower intestinal tract also. Without the starvation period, the inoculation of even massive numbers (10(10) cells) of the same organisms resulted in almost no detectable transfer. Some of the experimental animals on which a starvation period was imposed became carriers of either the inoculated recipient E. coli, or of R factor bearing coliforms, and these formed 1-10% of the total coliform population of the faeces for at least 6 weeks.

Animals↗

Histocompatibility antigens in active chronic hepatitis and primary biliary cirrhosis.

The frequency of antigens HL-A 1 (48%) and HL-A 8 (52%) in 54 patients with active chronic hepatitis from south-east England was significantly higher than in 89 control subjects from the same region (22% and 17% respectively). No correlation could be detected with the age and sex of the patients or with the presence of a particular immunological abnormality but the frequency of HL-A 1 and HL-A 8 was much lower in the nine patients who were positive for HBAg than in the 45 HBAg-negative cases. These results provide further evidence of the importance of genetic factors in active chronic hepatitis. In contrast the frequency of HL-A 1 and HL-A 8 in primary biliary cirrhosis, both in 45 patients from south-east England and in 28 patients from western Scotland, was not significantly different from that found in control groups from the same regions.

Age Factors↗

Hepatic disorders associated with liver-kidney microsomal antibodies.

A study of the clinical associations of a recently defined tissue autoantibody, the liver/kidney microsomal (L.K.M.) antibody, showed that out of 33 patients 26 had clinical liver disease. Fifteen of the patients had active chronic hepatitis and there were seven cases of acute hepatitis, precipitated by presumed virus A infection in three instances and by drug hypersensitivity in the other four. The remaining cases with liver disease included two with subclinical hepatitis and two with hepatocellular carcinoma. Evidence is presented that the patients with active chronic hepatitis may represent a distinct subgroup of the disease with a young mean age, an even male to female ratio, and a striking lack of other nonorgan-specific autoantibodies-that is, antinuclear and smooth muscle-which are usually present in the other autoimmune variant of the disease.

Adolescent↗

Cell-mediated immune responses in chronic liver diseases.

Studies of the cell-mediated response to liver antigens, using the leucocyte migration test, in 163 patients with various liver disorders showed that abnormal responses were almost confined to active chronic hepatitis (53% abnormal), primary biliary cirrhosis (64%), and cryptogenic cirrhosis (29%). The test was also abnormal in five out of seven patients with jaundice due to drug hypersensitivity and in one patient with acute infectious hepatitis at a time when mitochondrial antibodies were present in the serum. More of those with active chronic hepatitis on prednisone or azathioprine had normal tests than of those who were untreated, and in 8 out of 10 examined serially during therapy there was an accompanying improvement in leucocyte migration. Abnormal responses to salivary gland or kidney antigens were also found in nearly half of those with features of Sjögren's syndrome or renal tubular acidosis as part of a multisystem involvement-this, though occurring in cryptogenic cirrhosis, was found with greater frequency in active chronic hepatitis and primary biliary cirrhosis. These cell-mediated immune responses, perhaps triggered by the initial damage to the liver from viral or other agents, may be responsible both for the perpetuation of the liver disease and, because of common surface antigens, for the damage to other organs.

Acidosis, Renal Tubular↗