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Biomedical subjects

J G Schindler

Publications and source records attributed to J G Schindler.

At least 19 recordsLinked to original sources

[Ion-selective electro-analyser with tubular solid contact flow-through sensors for continuous bioelectrochemically controlled hemodialysis of K+, Na+, Ca2+, Cl- and pH].

An ion-selective electroanalyzer for bio-electrochemically controlled hemodialysis will be described. The bedside analysers are solid-contact flow-through electrodes based on tubular carrier-PVC-membranes for potassium, sodium, calcium and chloride. This multi-measurement system with series-connected biosensors in modular construction is provided with a chemosensor for pH measurements. Besides the technical aspects of the apparatus, the quantitative electrode characteristics and the fundamental basis for the application of ion activities in clinical analytic measurement will be described.

Acid-Base Equilibrium

[Electrochemical measuring system for the registration of transmucosal gastrointestinal potential differences].

An electrochemical measuring system for the recording of transmucosal gastrointestinal potential differences based on silver electrodes with double-junctions and continuous-flow saline bridges is described. Under bioelectrochemical control, a probe can passed from the esophagus via the stomach into the duodenum can be accurately assigned to each of these three segments of the intestine. Measurements are demonstrated and applications discussed.

Animals

[The influence of menstruation cycle on human parotid saliva composition (author's transl)].

The influence of different sexual hormone levels during menstrual cycle on the composition of human parotid saliva was investigated. During mid-cycle there were significantly enhanced concentrations of ionized calcium, total calcium, inorganic phosphate and sodium in parotid saliva. The changes in chloride concentrations were parallel to that of sodium and the excretion of postassium was inverse to that of sodium. The maximal out-put of total protein and alpha-amylase was found during midcycle and menstruation.

Fasting

[Investigations in the streaming blood of the alert animal and man. III. Postprandial and therapeutically induced changes of electrolyte concentration and hematocrit in man during hemodialysis (author's transl)].

Arterial haematocrit and blood electrolyte concentrations are measured continuously by conductometry in three hemodialysis patients. Haematocrit elevation during meals, particularly when rich in carbohydrates, indicate fluid losses into the gut. Simultaneous biphasic responses in electrolyte concentration indicate osmotic and diffusional shifts of water and electrolytes. Similarly, blood volume and electrolyte concentration changes can be followed during and after intravenous infusion of colloid and crystalloid solutions. The quantitative aspects of such measurements are discussed.

Adult

[Investigations on the performance of calcium selective disc-electrodes with electrically charged and neutral ligands in anaerobic serum measurements (author's transl)].

Anaerobically prepared serum samples from healthy subjects were simultaneously analysed for Ca++ in a flow-through-system of three ion selective disc-electrodes (electrochemical multimeasurementsystem). Two of the sensors contained electrically charged ligands, the third contained a neutral carrier. With neutral carriers an improvement of performance was noted in that there was a large increase in selectivity toward H+- and NH+4-ions and a distinct enhancement of reproducibility.

Anaerobiosis

[Ammonium-selective disc-electrode with the carrier-antibiotic nonactin. A method for the continuous enzymatic, electrochemical determination of urea, I (author's transl)].

An ammonium-selective disc-electrode is described; the membrane consists of a polyvinylchloride-matrix with an active phase of nonactin in tris (2-ethylhexyl)phosphate and diphenyl ether as the ion-selective plastic. One side of the membrane is in contact with the solution to be measured and the other with the front surface of a platinum wire, which is enclosed in acrylic glass. This arrangement results in a very low drift potential.

Anti-Bacterial Agents

[A NH(+4)-selective-enzymatic flow-through system. A method for the continuous enzymatic, electrochemical determination of urea, II (author's transl)].

A flow-through system for the measurement of urea concentrations is described, using soluble urease and consecutive determination of liberated ammonium ions by a selective disc-electrode. The active component of the electrode membrane was the carrier-antibiotic nonactin which was incorporated in a polyvinylchloride matrix.

Anti-Bacterial Agents

[A flow-through method for the O2-sensitive, enzymatic analysis of glucose (author's transl)].

A flow-through glucose-analyser is described based on an oxygen-sensitive enzymatic system. Leak-current-proof welded PTFE-membranes contribute considerably to an easy maintenance of the O2-sensors. Soluble or immobilized glucose oxidase may be used in automatic analysers. As a primary instrument of analysis, the oxygen pO2-electrode lends itself to the measurement of other enzymatic reactions that involve oxygen.

Autoanalysis