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Biomedical subjects

R Zander

Publications and source records attributed to R Zander.

At least 109 records · Page 6Linked to original sources
PubMed1981

[Assessment of potential blood substitute solutions with oxygen-carrying properties and their possible uses].

Beside the necessary volume effect (isoosmotic and isooncotic solution) and the physiological bicarbonate concentration (prevention of dilution acidosis) a possible blood substitute with O2 carrier characteristics should enable an optimal O2 transport: Viscosity as low as possible and shear rate independent (Newtonian behavior), O2 concentration at the given O2 partial pressure at least 6 ml/dl, and mean capillary O2 partial pressure as high as possible. For the judgement of such a blood substitute, the so-called O2 supply index is recommended, i.e., O2 concentration times mean capillary O2 partial pressure divided by viscosity.

Acid-Base Equilibrium↗
PubMed1979

Enzymatic sulfation of glycochenodeoxycholic acid by tissue fractions from adult hamsters.

Using a radiometric assay with glycochenodeoxycholic acid as substrate, bile acid:3'-phosphoadenosine-5'-phosphosulfate sulfotransferase activity was found in 105,000 g supernatant fractions of liver, proximal intestine, and adrenal gland homogenates from adult hamsters. Optimum conditions for measurement of the hepatic enzyme were determined. In both male and female animals sulfation only occurred at the 7 alpha-position. Saturation analysis with glycohenodeoxycholic acid revealed that the higher activity observed in fractions from female compared to male hamsters was due to a 4-fold lower apparent Km (79 muM vs. 317 muM) for this bile acid in the females. The sulfation of glycohenodeoxycholic acid was competitively inhibited by glycolithocholic acid, chenodeoxycholic acid, and ursodeoxycholic acid. The data are consistent with the concept that sulfation of many, if not all, bile acids can occur in vivo.

Adrenal Glands↗
PubMed1978

[Oxygen transport by solutions for blood replacement in comparison with other infusion solutions (author's transl)].

To investigate the oxygen transport capacity of solutions for blood replacement the oxygen solubility coefficients (ml/ml atm) at 37 degrees C of 12 solutions for volume replacement were determined and compared with those of 12 solutions for parenteral nutrition, 4 electrolyte solutions and 5 solutions for osmotherapy. All solutions for volume replacement have lower values for oxygen solubility than human plasma which shows a very constant oxygen solubility value even under extreme conditions. For clinical use of volume replacement solutions it is recommended that the oxygen solubility of the substitute be considered when any of the following conditions presents: a) large amounts are infused (hemodilution), b) isobar of hyperbar oxygen therapy is employed (hyperoxia), c) the body temperature is lowered (hypothermia). This is valid especially in the case of any impairment of the microcirculation.

Biological Transport↗
PubMed1975

[Experimental Research on the O2 supply of the eye author's transl].

To investigate the O2 supply conditions of the corneal endothelium and the lens by the aqueous hymor, O2 solubility coefficients of aqueous humor as well as in the lens had to be determined. The current assumption that the vitreous body is a possible O2 pool had to be examined. The following conclusions are drawn from the measured values of Bunsel O2 solubility coefficients (ml O2ml atm) of bovine aqueous humor, lens homogenates, vitreous bodys as well as of solutions of hyaluronic acid at temperatures from 10 to 40 degrees C: 1. The physiological rate of oxygen transport by the aqueous suffices to supply the corneal endothelium and the lens with oxygen, the temperature gradients within the anterior chamber favour the O2 supply of the corneal endothelium compared to other ocular tissues. 2. The O2 content of the aqueous can maintain O2 consumption of corneal endothelium for about 20 min theoretically or for about 5 min the lens ones. 3. The vitreous body can act as a possibel O2 pool only with regard to the O2 supply of the lens. In this case the pool can maintain O2 consumption of the shole lens for about 20 min. 4. During physiological growth of the lens the central part expands, which is characterized by an O2 concentration near zero. Therefore, the O2 supply of the lens is maintained for only less than one minute by the content of the lens itself.

Animals↗