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Biomedical subjects

G Birke

Publications and source records attributed to G Birke.

At least 19 recordsLinked to original sources
PubMed1976

A perfluorochemical oxygen carrier (fluosol-43) in a synthetic medium used for perfusion of isolated rat liver.

An emulsion of perfluorotributylamine (Fluosol-43) was used as substitute for the gas-carrying function of erythrocytes in a synthetic medium for perfusion of isolated rat liver. The efficiency and effect of this synthetic gas-carrier were evaluated from measurements of the concentrations of rat albumin, the unsaturated vitamin B12-binding capacity of small-molecular-size vitamin B12-binding proteins (UBBC of SBP), urea nitrogen, glucose, sodium, potassium, alanine amino transferase (ALAT) in the medium, and the incorporation of 14C-lysine into the circulating proteins. Secretion of bile, portal pressure, PO2, PCO2 and pH in the affluent and the effluent mediums were also measured. The results demonstrate that the oxygen-carrying capacity of the medium and the metabolic functions of the liver were higher, and the liver damage less, when the medium included Fluosol-43 than without it. The albumin synthesis and the secretion of bile were as high as has been reported for perfusions with erythrocytes. This indicates that the oxygen carried by the Fluosol-43 was utilised by the liver, and that the metabolic functions were not adversely affected during 4 h of perfusion by the medium containing Fluosol-43.

Alanine Transaminase↗
PubMed1975

Specific and unspecific removal of circulating noradrenaline in pulmonary and systemic vascular beds in man.

In order to study the extent and degree of specificity of the removal of circulating noradrenaline (NA) from the blood stream, during a single passage through the vascular beds of the lungs and of the forearm musculature of unanaesthetized, healthy young men, the following radiometric method was used: A misture of 3H-NA with 14C-inulin and 125I-labelled human serum albumin was injected proximally to the bed under study; six serial blood smaples were drawn distally to it, with about 15 s interval, and the disappearance of 3H-NA relatively to that of 14C-inulin and 125I-albumin was determined. 3H-NA was found to be removed from the blood stream in both these vascular beds. However, in the forearm the removal of 3H-NA was much greater, and apparently to a large extent due to specific trapping in the tissues, since the clearance of 3H-NA over the vascular bed of the forearm markedly exceeded that of 14C-inulin. During passage through the lungs removal of 3H-NA was less marked, and apparently largely unspecific, since it was initially essentially equal to that of 14C-inulin. This suggests that removal of circulating ergones of small molecular size, from the blood stream passing through the lungs, may occur initially by unspecific filtration/diffusion. Their subsequent fate would depend on whether the extraluminal tissues, supplied by the lung circulation, possess specific mechanisms for concentrating and/or inactivating each particular compound.

Adult↗
PubMed1975

Studies on isolated rat liver perfused by perfluoro-compound emulsion.

Isolated rat livers were perfused for 6 hours by different types of cell-free synthetic media. Some of the media included perfluoro-compounds as an oxygen carrier. The value of the perfusion medium as blood substitute was judged on the basis of observations and measurements of a number of parameters. These were: secretion of bile, fluid pressure in the portal vein, the level of GPT (ALAT) transaminase, urea nitrogen, and glucose in the perfusate. The rate of albumin synthesis and the rate of 14-C-lysine incorporated into circulating proteins were also measured. It was found that perfusion of the isolated rat liver with the TC-199 Difco medium containing the perfluoro-compound FC-80 emulsion maintained the liver in a good condition demonstrated, among other things, by the synthesis of albumin and other proteins. The liver could be kept in a good functional condition during 6 hours perfusion with this cell-free medium. With all the other types of perfusate tested the liver did not synthesize proteins. The isolated rat liver seems to be both convenient and advantageous for testing the perfusion media with respect to their capacity to maintain important metabolic functions.

Albumins↗