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Biomedical subjects

K Zimmer

Publications and source records attributed to K Zimmer.

33 records · Page 2Linked to original sources
PubMed1988

Performance of a demand oxygen saver system during rest, exercise, and sleep in hypoxemic patients.

Demand oxygen systems have been shown to be effective in treating hypoxemia during seated rest and during exercise, but the performance of these systems during sleep has not been previously studied. We compared the efficacy of a new demand oxygen saver system with that of continuous flow nasal oxygen during the usual activities of daily life including sleep, seated rest, and exercise. Six hypoxemic patients were studied. All six had chronic obstructive pulmonary disease, though one patient had kyphoscoliosis with mixed obstructive and restrictive lung disease. Patients were studied during each activity of daily life while receiving supplemental oxygen by continuous flow nasal cannula at 2 liters per minute and during use of the demand oxygen saver system. The demand oxygen system produced arterial oxygenation equivalent to continuous flow nasal cannula under all conditions while utilizing substantially less oxygen. When compared with administration of oxygen by continuous flow nasal cannula, the demand oxygen saver cannula utilized only 45 percent as much oxygen during seated rest, 44 percent as much oxygen during exercise, and 39 percent as much oxygen during sleep. Our data support the use of demand oxygen systems for treatment of hypoxemia in patients with chronic obstructive lung disease.

Aged↗
PubMed1985

Characteristics of the binding of aminoglycoside antibiotics to teichoic acids. A potential model system for interaction of aminoglycosides with polyanions.

The binding of the aminoglycoside antibiotic dihydrostreptomycin to defined cell-wall teichoic acids and to lipoteichoic acid isolated from various gram-positive eubacteria was followed by equilibrium dialysis. Dihydrostreptomycin was used at a wide range of concentration under different conditions of ionic strength, concentration of teichoic acid, presence of cationic molecules like Mg2+, spermidine, other aminoglycoside antibiotics (gentamicin, neomycin, paromomycin). Interaction of dihydrostreptomycin with teichoic acid was found to be a cooperative binding process. The binding characteristics seem to be dependent on structural features of teichoic acid and are influenced by cationic molecules. Mg2+, spermidine and other aminoglycosides antibiotics inhibit the binding of dihydrostreptomycin to teichoic acid competitively. The binding of aminoglycosides to teichoic acids is considered as a model system for the interaction of aminoglycoside antibiotics with cellular polyanions. Conclusions of physiological significance are drawn.

Aminoglycosides↗
PubMed1981

Effects of severe arterial hypocapnia on regional blood flow regulation, tissue PO2 and metabolism in the brain cortex of cats.

The effect of a stepwise decrease in PaCO2 from 3.9-1.6 kPa on rCBF, rCMRO2, tissue PO2 and concentrations of glucose, lactate, pyruvate, ATP, ADP, AMP and phosphocreatine in the brain cortex was studied in cats lightly anaesthetized with sodium pentobarbital. 1. Moderate lowering of PaCO2 to 2.5 kPa induced in all animals a homogeneous decrease of rCBF in corresponding areas of the right and left hemisphere. Mean rCBF fell from 129.2 to 103.1 ml X 100 g-1 X min-1, while rCMRO2 remained unchanged (12.7-12.9 ml X 100 g-1 X min-1). The tissue PO2 frequency histograms showed a shift to lower values without indicating the presence of brain tissue hypoxia. 2. Severe arterial hypocapnia (PaCO2 = 1.6 kPa) caused an inhomogeneous blood flow reaction. Both further decreased as well as increased rCBF values were measured simultaneously in the brain cortex of individual animals (mean rCBF = 97.6 ml X 100 g-1 X min-1). At the same time tissue PO2 measurements and metabolite assays indicated the presence of pronounced brain tissue hypoxia. The tissue concentrations of lactate and pyruvate and the lactate/pyruvate ratio were significantly increased, while the phosphocreatine concentration was significantly reduced. In addition, rCMRO2 decreased to 11.3 ml X 100 g-1 X min-1. The results provide conclusive evidence that severe arterial hypocapnia leads to an insufficient O2 supply of the brain cortex, which in turn seems to counteract the influence of hypocapnia on cortical blood flow regulation.

Adenine Nucleotides↗
PubMed1978

[Computer system for the automatic analysis of cath-lab data. Reliability of pattern-recognition and measurements (author's transl)].

The computer-system for the on-line-analysis of hemodynamic data developed in Aachen enables the clinical user to perform the immediate on-line analysis of ECG, pressure-curves and thermo- or dye-dilution-curves in a dialog mode. The procedure of pressure analysis as well as the calculations by the computer for the individual haemodynamic parameters are described. The comparison of the medical-manual evaluation of the pressure curves on paper-registration and the computer results of the same measurement shows a very good correlation for wave-recognitions and wave-measurements for this system, integrated in the daily routine since 24 months. As well in the application of various fluid-filled catheters used in praxis as in tip-manometers it could be proved for the pressure-analysis in the different positions of the heart, that the computer-system produced reliable evaluations for all catheter materials used. The flexible conception of the computer program with its fast adaption to new problems allows its use not only in the clinical routine, but also and especially in the handling of scientific questions in the frame-work of haemodynamic analysis.

Cardiac Catheterization↗