The effect of three days of blood glucose normalization by means of an "artificial endocrine pancreas" on the concentrations of growth hormone, glucagon, and cortisol in juvenile diabetics.

Glucagon, growth hormone, and cortisol secretion was studied in seven male insulin-dependent diabetics under conventional subcutaneous insulin therapy and after three days of blood glucose normalization attained by the artificial endocrine pancreas (Biostator-GCIIS). The diurnal hormonal profiles under the two types of therapy were compared. Six healthy male students served as control group. A three-day period of blood glucose normalization in insulin-dependent diabetic can restore glucagon secretion to normal. Growth hormone secretion is decreased but not completely normalised. Cortisol secretion is slightly decreased. It is concluded that prolonged normoglycemia achieved by means of an artificial endocrine pancreas may completely control endocrine abnormalities in insulin-dependent diabetics.     

Key parameters for outdoor biomass production of Scenedesmus obliquus in solar tracked photobioreactors

The biomass productivity of Scenedesmus obliquus was investigated outdoors during all seasons in solar tracked flat panel photobioreactors (PBR) to evaluate key parameters for process optimization. CO₂ was supplied by flue gas from an attached combined block heat and power plant. Waste heat from the power plant was used to heat the culture during winter. The parameters pH, CO₂, and inorganic salt concentrations were automatically adjusted to nonlimiting levels. The optimum biomass concentration increased directly with the photosynthetic active radiation (PAR) from 3 to 5 g dry weight (DW)?L^?1 for a low PAR of 10 mol photons m^?2 day^?1 and high PAR of 40–60 mol photons m^?2 day^?1, respectively. The annual average biomass yield (photosynthetic efficiency) was 0.4?±?0.5 g DW mol^?1 photons. However, biomass yields of 1.5 g DW mol^?1 photons close to the theoretical maximum were obtained at low PAR. The productivity (including the night biomass losses) ranged during all seasons from ?5 up to 30 g DW m^?2 day^?1 with a mean productivity of 9?±?7 g DW m^?2 day^?1. Low night temperatures of the culture medium and elevated day temperatures to the species-specific optimum increased the productivity. Thus, continuous regulation of the biomass concentration and the culture temperature with regard to the fluctuating weather conditions is essential for process optimization of outdoor microalgal production systems in temperate climates.     

Progress in practical endocrinology. The Glucosensor Unitec Ulm--a portable monitor for continuous blood glucose measurement

The Glucosensor Unitec Ulm is the first portable glucose sensor for continuous glucose monitoring in blood. The Glucosensor weighs 850 g and has a size of 15 x 19 x 7 cm. Over a 24 hr period 15-25 ml of blood are withdrawn for continuous measurement, depending on the pumping velocity. Its storing capacity for data of blood glucose readings amounts to 32 KB. With the Glucosensor "long-term glucograms" under near-normal conditions can be registered. The glucograms enable the physician to recognize the different deteriorations of glucose met- abolism eg. periods of silent hypoglycemia during the night as well as postprandial hyperglycemia. The degree of glycemic control of diabetic patients can be analyzed and the effect of blood glucose lowering therapeutics can be realistically assessed.     

Isolation and identification of alpha-methyloctanylcarnitines from human urine

Medium-chain acylcarnitines were isolated from human urine using a combination of chloroform-methanol extraction, silicic acid column and molecular sieving chromatography and preparative HPLC. Three purified acylcarnitines were analyzed by fast atom bombardment mass spectrometry and were also saponified and the free fatty acids analyzed by gas chromatography and mass spectrometry. Combined electron impact mass spectrometry and fast atom bombardment mass spectrometry and periodate oxidation for location of double bonds, demonstrated the occurrence of delta 6-octenylcarnitine, 2-methyloctanylcarnitine and 2-methyl-delta 6-octenylcarnitine. These acylcarnitines were present in the thirteen urines obtained from normal humans, but were not detected in urines from three individuals who had been on total parenteral nutrition for more than a year. The occurrence of alpha-methyl medium-chain acylcarnitines in human urine indicates a role for carnitine in excretion (detoxification) of these acyl derivatives.     

UeberRubus cancellatus Kern

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Neuere Bestrebungen auf dem Gebiete der botanischen Nomenclatur

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Die Bildung von Ablegern bei einigen Arten der GattungSempervivum und beiSedum dasyphyllum

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Ueber das Wechseln der Blüthenfarbe an einer und derselben Art in verschiedenen Gegenden

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Carnitine: a nutritional, biosynthetic, and functional perspective

Carnitine status in humans is reported to vary according to body composition, gender, and diet. Plasma carnitine concentration positively correlates with the dietary intake of carnitine. The content of carnitine in foodstuff is based on old and inadequate methodology. Nevertheless, dietary carnitine is important. The molecular biology of the enzymes of carnitine biosynthesis has recently been accomplished. Carnitine biosynthesis requires pathways in different tissues and is an efficient system. Overall biosynthesis is determined by the availability of trimethyllysine from tissue proteins. Carnitine deficiency resulting from a defect in biosynthesis has yet to be reported.

The role of carnitine in long-chain fatty acid oxidation is well defined. Recent evidence supports a role for the voltage-dependent anion channel in the transport of acyl-CoAs through the mitochondrial outer membrane. The mitochondrial outer membrane carnitine palmitoyltransferase-I in liver can be phosphorylated and when phosphorylated the sensitivity to malonyl-CoA is greatly decreased. This may explain the change in sensitivity of liver carnitine palmitoyltransferase-I observed during fasting and diabetes. Recently reported data clarify the role of carnitine and the carnitine transport system in the interplay between peroxisomes and mitochondrial fatty acid oxidation. Lastly, the buffering of the acyl-CoA/CoA coupled by carnitine reflects intracellular metabolism. This mass action effect underlies the use of carnitine as a therapeutic agent. In summary, these new observations help to further our understanding of the molecular aspects of carnitine in medicine.