Three-hour immobilization stress was imposed on male adult rats of Wistar strain by restraining them on a board 6 days a week for 1-8 weeks. The stressed rats showed less body weight gain during the experiment compared to the controls. These stressed animals manifested an improved cold tolerance as shown by no significant fall in colonic temperature in the cold at -5 degrees C for 300 min during the experimental period, while the colonic temperature of the controls fell progressively. Nonshivering thermogenesis as assessed by noradrenaline-induced increase in oxygen consumption was significantly potentiated in the stressed rats. The weight and protein content of the intercapsular brown adipose tissue (BAT) increased and BAT mitochondria were more packed in the stressed rats. Plasma insulin, insulin/glucagon molar ratio and thyroxine levels were lowered in the stressed rats, while the plasma triiodothyronine level remained unchanged. Removal of interscapular BAT led to a loss of improved cold tolerance and a significant reduction of nonshivering thermogenesis in the stressed rats. These results indicate that repetitive stress may induce cross adaptation between stress and cold through an enhanced capacity of nonshivering thermogenesis mediated, at least in part, via stimulation of BAT function.
Noradrenaline (NA) turnover of the interscapular brown adipose tissue (BAT) was determined in order to evaluate a role of sympathetic NA of this tissue in an enhanced nonshivering thermogenesis which had been previously evidenced in the repetitively stressed rats by immobilization (daily 3-h immobilization for 4 weeks) and the coldacclimated ones (5°C, 4 weeks). The disappearance rate of NA from the BAT following blockade of NA synthesis with a-methyl p-tyrosine was adopted for estimation of NA turnover of the tissue. Cold acclimation increased both fractional turnover rate (% /h) (k) and turnover rate (ngf (g BAT . h)). Repetitive immobilization stress also elevated turnover rate, but not k. In the warm non-stressed controls acute cold exposure to -5°C and acute immobilization stress elevated the turnover rate. The effect of cold exposure was significantly greater than that of immobilization stress for both indices of NA turnover. In the cold-acclimated rats acute cold exposure increased k as well as turnover rate, but not acute immobilization stress. In the repetitively immobilized rats both acute cold exposure and acute immobilization stress elevated k and turnover rate. These results indicate that immobilization enhances sympathetic activity of thermogenic tissue, BAT. The results also suggest that the extent of sympathetic participation is not necessarily the same between the cold-acclimated and the stressed rats.
To evaluate the role of adrenocortical hormones in stress- or cold-induced nonshivering thermogenesis, plasma corticosterone (CS) and deoxycorticosterone (DOCS) were measured with the aid of HPLC under various conditions. Repetitive immobilization stress (3 h/day, for 1 or 4 weeks) elevated the resting level (24 h after the last immobilization) of CS, but not DOCS. Acute stress (immobilization for 30 min) or cold exposure (-5 degrees C for 15 min) caused marked increases of CS and DOCS in both nonstressed naive controls and repetitively stressed rats. Four weeks, but not 1 week, of repetitive immobilization stress potentiated the responsiveness of CS to both acute stress and cold, and that of DOCS to acute stress, but not to cold. Cold acclimation (5 degrees C, 4 weeks) significantly elevated both corticosteroids but did not affect the resting levels (18 h after being transferred to 25 degrees C) or the responsiveness of both CS and DOCS to either acute stress or cold. These results suggest that repetitive immobilization stress, but not cold acclimation, could enhance nonshivering thermogenesis, at least in part, through an improvement in the responsiveness of adrenocortical hormone secretion to acute stress or cold.
Two cases of paraumbilical vein aneurysm are reported. The patients were diagnosed as having cirrhotic liver with portal hypertension. Angiography and contrast-enhanced computed tomography demonstrated a dilated paraumbilical vein arising from the left branch of the portal vein. Furthermore, localized dilatation of a paraumbilical vein was demonstrated. The focal aneurysmal dilatation of the dilatated paraumbilical vein is rare.
A case of primary biliary cirrhosis (PBC) associated with idiopathic thrombocytopenic purpura (ITP) is reported. The patient is a 59-year-old man. When he was 49 years old, he was diagnosed with ITP and received steroid therapy that successfully increased platelet numbers. However, the steroid therapy failed to normalize the elevated gamma-glutamyl transpeptidase. Ten years after this episode, he suffered from general itching and malaise and exhibited a gradual increase of serum biliary enzyme levels. Immunologically, IgM was increased and anti-mitochondrial antibody was positive. Histological findings of liver needle biopsy showed chronic non-suppurative destructive cholangitis, confirming the diagnosis of PBC. To date, very few PBC cases associated with ITP have been reported. Our case is the second one in Japan. PBC and ITP in our patient seemed to develop simultaneously, but the effect of steroid therapy on the two conditions was different. This result suggests that the autoimmune process may have been different in PBC and ITP in the present patient.
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