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Biomedical subjects

K Winnefeld

Publications and source records attributed to K Winnefeld.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Pharmacokinetics and nephrotoxicity of aluminum in rats of various ages].

Experiments were done in 5-, 10-, 20-, 33-, 55-, and 105-d-old rats to clarify whether or not age-dependent differences in pharmacokinetics and nephrotoxicity of Al exist. Using kidney function tests distinct signs of alumina (Al) nephrotoxicity can be demonstrated following 1 or 2 mg Al/100 g b. wt. i.p.: polyruria, reduced concentration of sodium in urine, elevated blood urea nitrogen concentrations. There is the same degree of nephrotoxicity both in adult and in young rats with an immature kidney function. Following administration of 2 mg Al/100 g b. wt. i. p. the initial plasma concentration of Al is distinctly lower in young than in adult rats. A rapid phase of elimination of Al from plasma (alpha-slope) is absent in 5-d-old rats and fully expressed in 33- and 55-d-old rats. In young rats the relative volume of distribution of Al is smaller than in adults. Following the administered dose nephrotoxicity in ducing concentrations of Al were obviously reached also in kidney tissue of young rats.

Aging↗
PubMed1986

[Desferal treatment of aluminum poisoning; effect on serum concentrations of aluminum (Al), iron (Fe) and copper (Cu)].

In 2 patients with a progressive dialysis encephalopathy and increased serum aluminium concentrations a Desferal-treatment with 500 mg per week was performed and in these cases the kinetics of Al, Fe, Cu was investigated. After the application of Desferal an increase of the serum levels, the ultrafiltrable proportion, the dialysance and the eliminated quantity of aluminium developed. In the course of the treatment in the two patients the aluminium level could be reduced to approximately normal values. Nevertheless one patient died of a severe course of a progressive dialysis encephalopathy. An increase of the copper concentration independent of Desferal-treatment after the dialysator passage remained without influence on the course of concentration of the serum copper in the examination period. A remarkable effect of the Desferal-therapy on the iron metabolism could not be established. Since in the dosage used there did not appear any side effects the Desferal-application is to characterized as a distinct and effective technique for the decrease of the serum-aluminium-concentration in patients undergoing dialysis.

Adult↗
PubMed1985

[Effect of Visotrast (R) and bilirubin on lipase and alpha-amylase activities of pancreatic secretions].

The contamination of pancreatic juice obtained by endoscopic retrograde catheterism of the papilla by cannulation of the pancreatic duct with contrast medium is possible. When the amount of "VisotrastR 370" is more then 0.05 ml per ml one observes a decrease of the lipase while alpha-amylase is unchanged.--Bilirubin has also an influence on the activity of lipase - but not on the alpha-amylase.

Bilirubin↗
PubMed1984

[Behavior of serum iron levels and total iron-binding capacity following gastrectomy].

Iron and the total iron binding capacity before and after an application of iron per os using the method of atomic absorption were determined in serum of 18 patients with a gastrectomy. The results were compared with a healthy group without a gastrectomy. We could not find significant disturbances of the enteral resorption of iron. But some patients show symptomes of a latent iron deficiency. After an operation the routine substitution of iron per os in patients without the stomach is indicated.

Adult↗
PubMed1981

Binding of magnesium and chloride ions to human hemoglobin A. Mg2+ concentrations in solutions simulating red cell conditions.

Ultrafiltration and direct determination of [Mg2+] by ion exchange were used to study the binding of Mg2+ and Cl- to isoionic human hemoglobin. A value of 58.8 +/- 1.7 l/mol was determined for the volume of hydrated hemoglobin from ultrafiltration of hemoglobin solutions containing 0.15-0.8 M glucose. In solutions with 5.7 mmol hemoglobin, 150 mmol KCl and 0.5-3.5 mmol MgCl2/l total water, 0.6 mol and 2 mol Cl- were bound/mol oxygenated and deoxygenated hemoglobin respectively. A value of about 11 l/mol was determined for the association constant of Mg2+ to hemoglobin monomer. Free Mg2+ concentrations were measured in hemoglobin solutions containing KCl, MgCl2, ATP and D-glycerate-2,3-bisphosphate at concentrations close to those of red cells. The experiments yielded 0.65 mmol/l free Mg2+ after oxygenation and 0.82 mmol/l after deoxygenation. The data indicate that only small changes of free Mg2+ levels in red cells are caused by physiological changes of pO2.

Chlorides↗
PubMed1981

[Isoelectric behavior of oxyhemoglobin].

This paper presents changes of the isoelectric behaviour of hemoglobin depending on the ionic strength and the buffer system. With increasing ionic strength the isoelectric point of oxy-hemoglobin changes to lower pH-values. The isoelectric function of oxy-hemoglobin is different in various buffer systems.

Buffers↗
PubMed1978

[Control of mitochondrial Mg++-efflux].

Inorganic phosphate stimulates the release of Mg++ from liver mitochondria, depending on concentration; a concentration as low as 0.1 mM phosphate is already effective. The process is dependent on the electron transfer of the respiratory chain, and its rate is highest under conditions of endogenous respiration and with ascorbate and TMPD as substrates, respectively. The phosphate stimulated release of Mg++ is followed, with a pronounced delay, by a Ca++ efflux and a swelling of mitochondria. Addition of EGTA strongly reduced the rate of Mg++ liberation in the presence and absence of inorganic phosphate. Exogenous Ca++ is able to abolish the EGTA effect. ADP and ATP inhibit the phosphate stimulated release of Mg++. Phosphoenol pyruvate and free fatty acids enhance the rate of Mg++ and Ca++ efflux from the mitochondria. The results permit the conclusion that inorganic phosphate, Ca++ and various metabolites of the cell metabolism influence the Mg++ distribution between the extra- and intramitochondrial space, thus controlling the permeability of the mitochondrial inner membrane for monovalent cations.

Animals↗