Hormone response of diabetic patients to exercise at cool and warm temperatures

Both exercise and high ambient temperatures stimulate the secretion of counterregulatory hormones which can change glucose homeostasis. We studied whether in diabetic patients there are any differences in the hormonal response to exercise performed at cool or warm ambient temperatures. A study was performed on eight male insulin-dependent patients at rest and during exercise at +10 degrees C and +30 degrees C. Exercise consisted of three consecutive 15-min periods at 60% of maximal aerobic capacity. The concentrations of plasma lactate and counterregulatory hormones at rest were similar at warm and cool temperature, whereas prolactin concentration was higher (P less than 0.01) at +30 degrees C. Exercise resulted in an increase in noradrenaline, growth hormone and prolactin (P less than 0.01), prevented the diurnal decrease in cortisol, but had no effect on glucagon. Hormone responses to exercise were similar at +10 degrees C and at +30 degrees C, except for cortisol and noradrenaline which showed greater responses at warm than at cool temperatures. This may have been due to the higher relative work load at warm compared to cool temperatures as suggested by the higher heart rate and greater increase of lactate at +30 degrees C. These data indicate that within a range of ambient temperatures commonly occurring in sports, the response of counterregulatory hormones is largely independent of ambient temperature in insulin-dependent diabetic patients.     

Bovine and ovine leukemia viruses. I. Characterization of viral antigens.

A comparative study on several virus-specific antigens of bovine and ovine leukemia viruses is presented. In addition to the major immunologically reactive, nonglycosylated antigen p21, which has a molecular weight of 21,000, both viruses share two glycoproteins of apparent molecular weights of 60,000 (gp60) and 32,000 (gp32), respectively. Immunological cross-reaction suggests that ovine and bovine leukemia viruses are genetically highly related.     

PI5P4Ks drive metabolic homeostasis through peroxisome-mitochondria interplay

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Effects of temperature on spring bloom dynamics of epilithic diatom communities in the Gulf of Bothnia

Abstract. In order to forecast consequences of climatic changes for littoral algae in coastal ecosystems, the effects of temperature increase on spring bloom dynamics of epilithic diatom communities were studied in two ways: (1) Communities were compared from sites receiving different amounts of cooling water discharge from a nuclear power plant. (2) Communities from the exceptionally warm spring of 1989 were compared with those from the same sites in the preceding normal years. The studies were carried out in and around the Forsmark Biotest Basin, an artificial waterbody that receives brackish cooling water from the Forsmark nuclear power plant on the Swedish east coast. Species composition and biomass data from 200 epilithic diatom samples taken in the period January-May from 1983 to 1989 were analysed. Multiple regression analysis was used to show the responses of diatom cover, community diversity and abundances of individual taxa to water temperature and other environmental factors. Constrained ordination (CCA) was used to display the relationship of overall community composition to environment. Increased water temperature resulted in higher biomass through a chain of ecological effects. Strong reduction of ice cover was crucial in this chain, resulting in reduced loss of diatom cells by reduced abrading and higher primary production by higher availability of light, nutrients and substrate. The conclusion is that large blooms of fast-growing epilithic diatoms in large colonies can occupy the niche that emerges when the ice-free season is prolonged in the northern Baltic Sea and areas similar in salinity and climatic conditions. Dramatic species shifts may only be expected if the winter ice cover is totally absent.