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Comment-The normal secretion ofgrowth hormone is inhibited by somatostatin and stimulated by growth hormone releasing factor. The same effects are also evident in most patients with acromegaly. Release of somatostatin may be stimulated and release of growth hormone releasing factor inhibited by reduced hypothalamic dopamine content, which in turn may be caused by chronic hyperprolactinaemia.5The hyperprolactinaemia in our patient may thus have led to increased release of somatostatin and decreased release of growth hormone releasing factor, reflected by the "low" growth hormone concentrations despite this patient's longlasting, clinically active acromegaly. Treatment with a dopamine agonist inhibited prolactin secretion, which was followed by increased hypothalamic dopamine content. Release of somatostatin might then have been reduced and release of growth hormone releasing factor increased, leading to the rapid increase in growth hormone concentrations and the enlargement of the pituitary tumour. We assessed the prevalence of markers of hepatitis B virus in all white expatriate staff and their families attending routine physical examinations during one year.
Subjects, methods, and resultsWe included 234 subjects in the trial: 117 were resident in Thailand, 98 in Indonesia, and 19 in the Philippines. Radioimmunoassay (Ausria 11, Corab, and Ausab-RIA; Abbott) or enzyme immunoassay (Auszyme, Corzyme, and Ausab-EIA; Abbott) was used to test for the presence of hepatitis B surface antigen, antibody to hepatitis B core antigen, and antibody to hepatitis B surface antigen. Testing for hepatitis B virus had not been done before the staffwent to South East Asia, but the prevalence of markers ofhepatitis B virus in similar low risk groups is only 3-5%.' Activities of alanine aminotransferase, aspartate aminotransferase, and y-glutamyltransferase were measured at each examination.The table shows that a significantly greater proportion of married men were positive for hepatitis B virus compared with married women and dependants. The men were divided into groups according to their length of stay in South East Asia. The proportion of married men who were seropositive was: among those who were in the first year oftheir stay 0% (0/11), second year 9% (2/22), third 18% (6/34), fourth 16% (3/19), fifth 47% (9/19), and sixth or more 43% (12/28) (p= 0-0001). A higher proportion of single men were seropositive after a fairly short time in the area, but there was no consistent trend with length of stay.Among married men in their 30s, 40s, and 50s the proportion positive for hepatitis B virus was 18% (9/50), 39% (17/44), and 21% (5/24), respectively. Eleven out of 21 (52%) who were in their 40s and had been in the area for five or more years were seropositive. Among married office employees 10% (8/82) were positive for hepatitis B virus, compared with 47% (24/5 1) of married field employees (p=0-001). Among single male office employees 29% (5/17) were positive for hepatitis B virus, compared with 40% (4/10) ofsingle-field employe...
