SUMMARYIn order to survive cold northern winters, honeybees crowd tightly together in a winter cluster. Present models of winter cluster thermoregulation consider the insulation by the tightly packed mantle bees as the decisive factor for survival at low temperatures, mostly ignoring the possibility of endothermic heat production. We provide here direct evidence of endothermic heat production by `shivering' thermogenesis. The abundance of endothermic bees is highest in the core and decreases towards the surface. This shows that core bees play an active role in thermal control of winter clusters. We conclude that regulation of both the insulation by the mantle bees and endothermic heat production by the inner bees is necessary to achieve thermal stability in a winter cluster.

No abstract

Compared to conventional human premixed insulin the prandial therapy with biphasic insulin aspart results not only in an improvement of glucose tolerance but also in a significant reduction of postprandial hyperlipemia.

OBJECTIVEContinuously administered insulin is limited by the need for frequent blood glucose measurements, dose adjustments, and risk of hypoglycemia. Regimens based on glucagon-like peptide 1 (GLP-1) could represent a less complicated treatment alternative. This alternative might be advantageous in hyperglycemic patients hospitalized for acute critical illnesses, who benefit from near normoglycemic control.RESEARCH DESIGN AND METHODSIn a prospective open randomized crossover trial, we investigated eight clinically stable type 2 diabetic patients during intravenous insulin or GLP-1 regimens to normalize blood glucose after a standardized breakfast.RESULTSThe time to reach a plasma glucose below 115 mg/dl was significantly shorter during GLP-1 administration (252 ± 51 vs. 321 ± 43 min, P < 0.01). Maximum glycemia (312 ± 51 vs. 254 ± 48 mg/dl, P < 0.01) and glycemia after 2 h (271 ± 51 vs. 168 ± 48 mg/dl, P = 0.012) and after 4 h (155 ± 51 vs. 116 ± 27 mg/dl, P = 0.02) were significantly lower during GLP-1 administration.CONCLUSIONSGLP-1 infusion is superior to an established insulin infusion regimen with regard to effectiveness and practicability.

No abstract