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Biomedical subjects

K Fendler

Publications and source records attributed to K Fendler.

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

Human tolerability and pharmacodynamic study of Tisacid tablet in duodenal ulcer patients. A prospective, randomized, self-controlled clinicopharmacological study.

A randomized, prospective, crossing-over clinico-pharmacological study was conducted on the tolerability by humans, of TISACID (Al-Mg-hydroxy-carbonate), a new antacid of up-to-date composition produced in Hungary. Even a relatively high dose of the preparation is tolerated by the human organism. During a 6-week continuous treatment neither subjective nor objective side-effects were observed. The tablet is immediately decomposed in the gastric juice, a considerable portion of it will permanently stick to the mucosa of the stomach and duodenum. Depending on the dose, it rapidly and permanently reduces the acidity of the gastric content and increases serum gastrin concentration only moderately and for a short time. Administered together with cimetidine, it promotes healing of duodenal ulcer and the cessation of complaints. It does not increase the aluminium and magnesium concentrations of the plasma not even on prolonged administration, and clinical symptoms and laboratory changes characterizing the phosphate depletion syndrome do not develop either. Based on the results, authors consider Tisacid a beneficial preparation as regards both effectivity and tolerability.

Aluminum Hydroxide↗
PubMed1987

Kinetics of pump currents generated by the Na+,K+-ATPase.

Purified Na+,K+-ATPase from pig kidney was attached to black lipid membranes. Pump currents of the enzyme could be measured with a time resolution of approx. 1 ms by releasing ATP from caged ATP with a UV laser flash. Analysis of the transient currents shows that a slow non-electrogenic step is followed by an electrogenic transition with a rate constant of 100 s-1 (22 degrees C). The exponential components found in the transient currents are compared to transitions in the Albers-Post scheme.

Adenosine Triphosphate↗
PubMed1987

Na+ currents generated by the purified (Na+ + K+)-ATPase on planar lipid membranes.

Purified (Na+ + K+)-ATPase from pig kidney was attached to black lipid membranes and ATP-induced electric currents were measured as described previously by Fendler et al. ((1985) EMBO J. 4, 3079-3085). An ATP concentration jump was produced by an ultraviolet-light flash converting non-hydrolysable caged ATP to ATP. In the presence of Na+ and Mg2+ this resulted in a transient current signal. The pump current was not only ATP dependent, but also was influenced by the ATP/caged ATP ratio. It was concluded that caged ATP binds to the enzyme (and hence inhibits the signal) with a Ki of approx. 30 microM, which was confirmed by enzymatic activity studies. An ATP affinity of approx. 2 microM was determined. The addition of the protonophore 1799 and the Me+/H+ exchanger monensin made the bilayer conductive leading to a stationary pump current. The stationary current was strongly increased by the addition of K+ with a K0.5 of 700 microM. Even in the absence of K+ a stationary current could be measured, which showed two Na+-affinities: a high-affinity (K0.5 less than or equal to 1 mM) and a low-affinity (K0.5 greater than or equal to 0.2 M). In order to explain the sustained electrogenic Na+ transport during the Na+-ATPase activity, it is proposed, that Na+ can replace K+ in dephosphorylating the enzyme, but binds about 1000-times weaker than K+. The ATP requirement of the Na+-ATPase was the same (K0.5 = 2 microM) with regard to the peak currents and the stationary currents. However, for the (Na+ + K+)-ATPase the stationary currents required more ATP. The results are discussed on the basis of the Albers-Post scheme.

Adenosine Triphosphate↗
PubMed1986

[Clinical experience with heparinoid sodium pentosan polysulfate (SP54) in the treatment of cerebral ischemia].

Fifty-five patients suffering from acute cerebral ischaemia were treated with pentosan polysulphate (SP54) intravenously and subsequently orally. The control group consisting of 35 patients received the infusion solution and vasodilator drugs. The statistically significant changes appearing following infusion of SP54 include the following parameters: haematocrit, blood viscosity and cholesterol concentrations. In individual cases the euglobulin lysis time was shortened within two hours after the beginning of the infusion. As demonstrated by the statistically reliable results in patients treated with SP54 the neurological symptoms improved significantly within the first two weeks after the onset of the disease compared to the control groups. Based on case reports, recommendations are given for the indication and contraindication of SP54 treatment in cerebral ischaemia.

Administration, Oral↗
PubMed1985

Pump currents generated by the purified Na+K+-ATPase from kidney on black lipid membranes.

The transport activity of purified Na+K+-ATPase was investigated by measuring the electrical pump current induced on black lipid membranes. Discs containing purified Na+K+-ATPase from pig kidney were attached to planar lipid bilayers in a sandwich-like structure. After the addition of only microM concentrations of an inactive photolabile ATP derivative [P3-1-(2-nitro)phenylethyladenosine 5'-triphosphate, caged ATP] ATP was released after illumination with u.v.-light, which led to a transient current in the system. The transient photoresponse indicates that the discs and the underlying membrane are capacitatively coupled. Stationary pump currents were obtained after the addition of the H+, Na+ exchanging agent monensin together with valinomycin to the membrane system, which increased the permeability of the black lipid membrane for the pumped ions. In the absence of ADP and Pi the half saturation for the maximal photoeffect was obtained at 6.5 microM released ATP. The addition of ADP decreased the pump activity. Pump activity was obtained only in the presence of Mg2+ together with Na+ and Na+ and K+. No pump current was obtained in the presence of Mg2+ together with K+. The electrical response was blocked completely by the Na+K+-ATPase-specific inhibitors vanadate and ouabain. No pump currents were observed with a chemically modified protein, which was labelled on the ATP binding site with fluoresceine isothiocyanate. The method described offers the possibility of investigating by direct electrical measurements ion transport of Na+K+-ATPase with a large variety of different parameters.

Animals↗
PubMed1977

Investigation of adaptive processes in child and adolescent swimmers. Acid-base parameters of swimmers and weight-lifters.

Acid-base parameters of adolescent swimmers (capacitive sport) and of adult weight-lifters (athletoid sport) were investigated before and after training in the submaximally trained phase of a year-round training period. In swimmers, training induced incompensated metabolic acidosis, which persisted at 10 min after the training. This acidosis showed no correlation to the blood lactate level. In weight-lifters, there was only a slight, compensated posttraining acidosis, which tended to decrease 10 min after the training. The weight-lifters had extremely high posttraining ammonia levels. It might be supposed that ammonia-genesis has a role in the compensation of exercise-induced acidosis in weight-lifters. The differences in acid-base status of swimmers and weight-lifters might be related to the different breathing mechanism needed for the two different sports.

Acid-Base Equilibrium↗
PubMed1977

Adaptive processes in child and adolescent swimmers. Blood coagulation and viscosity.

Multifactorial studies were performed in child and adolescent swimmers in the early period of training and in a submaximum state of training in the year's racing period. Blood coagulation, viscosity, acidity, protein metabolism, muscle enzymes, ions, haematologic, cardiac and endocrine parameters have been investigated. In the early period of training, physical exercise resulted in fibrinolysis, and a decrease in the fibrinogen and prothrombin levels and the platelet count. The same exercise in fully-trained organisms failed to produce such changes. Data concerning acidity, protein metabolism, muscle enzymes, ions, haematologic, cardiac and endocrine parameters will be published in subsequent papers.

Adaptation, Physiological↗