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Biomedical subjects

L F Barker

Publications and source records attributed to L F Barker.

At least 91 records · Page 5Linked to original sources
PubMed1973

Immunological studies in Ugandan patients with hepatocellular carcinoma.

Immunological studies were performed on Ugandan patients with hepatocellular carcinoma to test the hypothesis that the high rate of persistence of hepatitis-associated antigen in these patients is the result of defects in host immune response. The responses to 1-chloro-2,4-dinitrobenzene sensitization and to a battery of recall skin test antigens were normal, as was the humoral antibody response to tularaemia antigen. Neither hypogammaglobulinaemia nor specific immunoglobulin deficiencies were found. Thus it appears unlikely that generalized defects in host immune responses can account for the high incidence of persistent hepatitis B virus infection found in Ugandan patients with hepatocellular carcinoma.

Adult↗
PubMed1973

Liver cell dysplasia: a premalignant condition.

Liver cell dysplasia is defined as cellular enlargement, nuclear pleomorphism, and multinucleation of liver cells occurring in groups or occupying whole cirrhotic nodules. The prevalence, natural history, and relationship to the Australia or hepatitis-associated antigen (HAA) have been studied in 552 Ugandan African patients with normal, cirrhotic, and cancerous livers. Liver cell dysplasia was found in only two of 200 (1%) patients with normal livers, in three of 43 (6.9%) of patients with normal livers bearing primary liver cell carcinoma, 35 of 175 (20.3%) patients with cirrhosis, and 80 of 124 (64.5%) of patients with cirrhosis and primary liver cell carcinoma. Cirrhotic patients without dysplasia were, on average, ten years younger than those with dysplasia and the latter were on average six years younger than those with cirrhosis and carcinoma. Liver cell dysplasia occurred more frequently in males than in females. It was found in all but one instance in macronodular or mixed forms of cirrhosis only. There was a strong relationship between dysplasia and the presence of HAA in 104 patients that suggests a possible carcinogenic mechanism for the longincubation (serum or B) hepatitis virus in liver cell carcinoma. It is concluded that the presence of liver cell dysplasia identifies a group of patients with a high risk of liver cell carcinoma and that they should be followed up by serial alpha-fetoprotein estimations.

Adolescent↗
PubMed1972

Hepatitis-associated antigen and antibody in Uganda: correlation of serological testing with histopathology.

Histopathological findings in 91 Ugandan patients with cirrhosis were studied in relation to serological tests for the hepatitis-associated antigen (H.A.A.) and antibody (anti-H.A.A.). H.A.A. was present in 30 (32.9%) of the 91 patients as opposed to 7 (3.1%) out of 224 controls drawn from the same population (P<0.001). Younger subjects and males were more frequently positive. There was no difference in the presence of anti-H.A.A. between patients and controls. Correlation of the results of serological testing with histopathological features showed that macronodular ("posthepatitic," "postnecrotic") types of cirrhosis, which predominate in Uganda, were associated with the presence of H.A.A. but that the much less common micronodular ("nutritional," fatty, portal) type of cirrhosis was not. Evidence was found, on the other hand, for a direct role of alcoholism in the latter. Detailed histological analysis also showed two types of cellular change-liver cell swelling and dysplasia-to be associated with the presence of H.A.A. The data suggest an aetiological role for H.A.A. in most cases of cirrhosis in Uganda and these may be identified by histological criteria.

Age Factors↗
PubMed1972

Evaluation of assay methods for hepatitis-associated antigen.

Assay methods for hepatitis-associated antigen (HAA) were evaluated for sensitivity, or reproducibility, or both in a series of three trials in which both research and service-oriented laboratories participated. Agar-gel diffusion (AGD) methods were found to be the least sensitive and reproducible of the commonly employed assay methods. Complement fixation (CF) tests were consistently more sensitive than either AGD or counterelectrophoresis (CEP) methods for detection of HAA. With judicious choice of the antibody reagent, sensitivity of CEP techniques was equivalent to CF methods of HAA detection. None of the three major assay methods (AGD, CEP, or CF) compared in this study were capable of consistently detecting HAA when it was present in relatively low concentrations in human serum.

Agar↗
PubMed1971

Australia antigen and hepatitis in Accra, Ghana.

Viral hepatitis in young adults in Accra, Ghana, is associated with Australia antigen (H.A.A.). Sera from 85 patients in hospital with viral hepatitis were available for determinations of H.A.A. Of the 16 patients whose serum was obtained within the first week of symptoms, 15 were positive. The only factor related to finding H.A.A. was the time between onset of symptoms and the collection of the serum sample. Persistence of H.A.A. was associated with persistence of jaundice in men but not in women. Previous epidemiological studies in Accra found no evidence for parenteral transmission of viral hepatitis and showed a shanty-town predilection pointing to faecal-oral transmission. It thus seems that H.A.A.-associated hepatitis is transmitted in West Africa either faecal-orally or by shanty-town associated arthropods. The finding that H.A.A. hepatitis is the usual hepatitis in young adults in Accra is in accord with the high prevalence of H.A.A. elsewhere in the general population in Africa and may be related to the high rate of cirrhosis and hepatoma in Africa.

Adolescent↗