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Biomedical subjects

J Seggie

Publications and source records attributed to J Seggie.

At least 55 records · Page 3Linked to original sources
PubMed1980

Behavioral, corticosterone, and prolactin responses to novel environment in rats with fornix transections.

These experiments examined the behavioral, corticosterone, and prolactin responses to a novel environmental in male rats with total fornix transections. During the initial exposure to the novel environment, rats with fornix transections exhibited increased latency to initiate activity and increased activity levels. There were no changes in frequency of rearing, frequency of interactions with objects in the environment, or defecation. Fornix transection was found to have no effect on resting levels of either corticosterone or prolactin but to alter significantly the stress-response profiles of each of these hormones. The corticosterone responses to the novel environment in rats with fornix lesions were of greater magnitude with no change in latency to respond or in recovery of resting levels, whereas the prolactin responses were of shorter latency with no change in magnitude or recovery or resting levels. Habituating to the novel environment by repeated exposure was found to decrease the corticosterone responses of rats with fornix lesions but not the responses of controls. The results are discussed in terms of differences between rats with fornix lesions and control rats in level of arousal and effect of experience in the environment.

Animals↗
PubMed1980

Amygdala lesions and 24-h variation in plasma corticosterone, growth hormone, and prolactin levels.

The effects of destruction of the whole amygdala complex on 24-h variations in resting corticosterone, growth hormone, and prolactin levels were investigated in male rats. All three hormones showed the expected resting levels and 24-h variations as previously reported. Bilateral destruction of the amygdala had no effect on either the resting levels or the 24-h variations of these hormones. Thus integrity of the amygdala is not essential for the normal basal and diurnal hormone profile of corticosterone, growth hormone, and prolactin.

Amygdala↗
PubMed1979

Patterns of hepatic injury induced by methyldopa.

Twelve patients with liver disease related to methyldopa were seen between 1967 and 1977. Illness occurred within 1--9 weeks of commencement of therapy in 9 patients, the remaining 3 patients having received the drug for 13 months, 15 months and 7 years before experiencing symptoms. Jaundice with tender hepatomegaly, usually preceded by symptoms of malaise, anorexia, nausea and vomiting, and associated with upper abdominal pain, was an invariable finding in all patients. Biochemical liver function tests indicated hepatocellular necrosis and correlated with histopathological evidence of hepatic injury, the spectrum of which ranged from fatty change and focal hepatocellular necrosis to massive hepatic necrosis. Most patients showed moderate to severe acute hepatitis or chronic active hepatitis with associated cholestasis. The drug was withdrawn on presentation to hospital in 11 patients, with rapid clinical improvement in 9. One patient died, having presented in hepatic failure, and another, who had been taking methyldopa for 7 years, showed slower clinical and biochemical resolution over a period of several months. The remaining patient in the series developed fulminant hepatitis when the drug was accidentally recommenced 1 year after a prior episode of methyldopa-induced hepatitis. In this latter patient, and in 2 others, the causal relationship between methyldopa and hepatic dysfunction was proved with the recurrence of hepatitis within 2 weeks of re-exposure to the drug.

Adult↗
PubMed1979

Differential effects of basolateral amygdala lesions on behavior, corticosterone, and prolactin responses.

The present experiment examines hormone-behavior relationships following manipulation of the amygdala. Affective behavior and levels of corticosterone and prolactin were compared in rats with lesions of the basolateral amygdala and in nonlesioned and sham-operated controls. Animals with lesions of the basolateral amygdala were found to be hyperreactive and to have normal resting levels of corticosterone and prolactin but potentiated corticosterone responses to stress. Normal prolactin stress responses were unaltered by the lesion. The results are discussed in relation to behavioral and endocrine changes seen following other limbic system lesions.

Amygdala↗
PubMed1977

Cirrhosis of the liver in Rhodesian Blacks.

Thirty-five Black patients with cirrhosis of the liver were admitted to the professorial unit over a 1-year period and were included in a carefully planned prospective study. Men predominated over women in a ratio of 3:1. Alcohol consumption in the form of African beer was significantly higher in cirrhotic patients than in a control population. The clinical picture was neither predominantly that of alcoholic nor of cryptogenic cirrhosis. Hepatomegaly, porphyria cutanea tarda, ascites, splenomegaly and oesophageal varices were common. There was a complete absence of gynaecomastia, spider naevi and liver palms. Histologically, the majority of patients had macronodular cirrhosis, and only 1 patient had micronodular cirrhosis and minimal fatty change. Hepatitis B surface antigen (HbsAg) was not detected in any patient, despite a positive HbAg rate of 4% in Black African blood donors, determined by means of the same laboratory technique.

Adult↗
PubMed1977

Hepatocellular carcinoma in the Rhodesian African.

We have carried out a prospective survey of 28 primary liver carcinomas over one year. Hepatocellular carcinoma is the commonest malignancy seen in Rhodesian blacks, which results in a high index of suspicion and accounts for the 96.4% positive diagnosis before death in this study. The age distribution was evenly spread through adult life with no definite peak incidence. Some were young and without evidence of chronic liver disease, but many had the stigmata of established hepatic disease. This contrasts with the common assertion that in areas of high incidence for primary liver cancer those affected are mainly young and lack signs of chronic liver disease. The commonest presenting symptoms were abdominal pain and swelling and weight loss. Hepatomegaly, often tender and nodular, was present in all but one. The incidence of alpha-feto protein, 46.5%, is low compared with other countries where primary liver cancer is common. Hepatitis B antigen was absent in all 28, suggesting that there is no association between the persistence of the antigen and hepatocellular carcinoma in Rhodesia. Liver function tests, although abnormal, were never diagnostic of primary liver cancer. We have confirmed the association of high alcohol consumption and cirrhosis with hepatocellular carcinoma.

Adult↗
PubMed1977

Effect of psychosocial stimuli and limbic lesions on prolactin at rest and following stress.

Many of the factors altering corticosterone in the rat have similar effects on prolactin. Resting prolactin, like corticosterone, is higher in animals housed singly than in those multiply housed. Unlike corticosterone, gentling did not lower prolactin. An exquisite sensitivity to environmental stimuli which results in rapid elevations in prolactin levels has been indentified in the rat which is considerably greater than that for corticosterone. Like corticosterone, the pattern of prolactin stress responses varies according to time of day. This differential sensitivity may well account for the diurnal variation in prolactin reported by some investigators. The limbic system has an important influence on prolactin. Lesions of the septal region do not modify resting levels but alter the pattern of prolactin stress responses in ways which are only partly similar to the effects of such lesions on corticosterone. In rhesus monkeys, individual variation in resting prolactin levels was observed, similar to that seen in the human. Levels are stable over periods of up to 50 days and are characteristic of the individual animal. In response to the stress of electric shock or shaping to a bar press response, prolactin elevation occurs only in animals with high resting levels, suggesting that a common mechanism is responsible for controlling both resting levels and magnitude of stress responses.

Animals↗
PubMed1976

Twenty-four-hour resting prolactin levels in male rats: the effect of septal lesions and order of sacrifice.

Diurnal variation in resting prolactin levels was studied in male rats that were normal, sham-operated, or lesioned in the septal nuclei. Separate groups of rats were sampled by decapitation every 3 or 4 hours in two separate studies during a 24 h period consisting of 12 h light and 12 h dark. Male rats did not exhibit a significant diurnal variation in resting prolactin levels. A septal lesion had no effect on resting prolactin levels. Prolactin levels were found to be highly responsive to environmental disturbances and were subject to the effects of sequential sacrificing procedures. The possibility was raised that prolactin exhibits a diurnal variation in sensitivity to stress which varies as a function of circulating levels of corticosterone.

Animals↗
PubMed1976

Coping with stress: parallelism between the effects of septal lesions on growth hormone and corticosterone levels.

In order to characterize the effects of a septal lesion on plasma growth hormone levels, blood samples were taken from normal and sham-operated rats and rats with a bilateral septal lesion under conditions of rest and following stressful stimulation. Nonlesioned control rats evidenced a significant base line diurnal rhythm in plasma growth hormone levels which was unaffected by a septal lesion. In response to stress, plasma growth hormone levels evidenced a significant drop. Minimum levels were reached 15 min after stimulation and remained depressed during 1 hr of observation after stimulation. Rats with a septal lesion evidenced the same pattern of growth hormone response to stressful stimulation as nonlesioned rats, however the magnitude of response was potentiated in septal rats. The present data were compared to the previously published corticosterone data from the same animals. A septal lesion has similar effects on boting 24-hour rhythm of either of these hormones but potentiated the response of both corticosterone and growth hormone to stress even though the direction of response is opposite. The results are interpreted as suggesting the septum is an element in some central coping mechanism which is involved when an organism reacts to environmental demands. Preliminary data further suggest that the same central coping mechanism is involved in both the behavioral and hormonal responses to stress.

Animals↗
PubMed1975

Serum alpha-feto protein (alpha-FP) and hepatoma in Rhodesian Africans.

Alpha-feto protein (alpha-FP) is now accepted as a very useful serum marker of hepatocarcinoma, and since its discovery in 1963, surveys have been carried out in various regions of the world, where hepatoma is particularly prevalent, which have shown that alpha-FP may be detected in 50 to 80% of patients with liver cancer. The sera of 30 Rhodesian African patients with histologically proven hepatoma were tested in this study for the presence of alpha-FP. In only 47% was alpha-FP detected. Thus it is our experience that a positive result is strong evidence in favour of a diagnosis of hepatocarcinoma whilst a negative result is of little value, necessitating that liver biopsy be carried out in all patients with clinical suspicion of liver cancer.

Adolescent↗