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Biomedical subjects

J Koch

Publications and source records attributed to J Koch.

At least 235 records · Page 13Linked to original sources
PubMed1985

[Development of anxiety arousal in group psychotherapy].

37 patients taken from three psychotherapy groups had completed a course of communication training as preparation for dynamic group psychotherapy. Two anxiety tests were performed at different times before, during and after the therapy. After completion of the communication training, the anxiety diminished as a result of general factors that had come into effect. After completion of the dynamic group psychotherapy they diminished owing to a genuine improvement in social competence. The different modes of action of two psychotherapeutic methods are clearly shown.

Anxiety Disorders↗
PubMed1984

Effects of vanadate on intracellular reduction equivalents in mouse liver and the fate of vanadium in plasma, erythrocytes and liver.

Intraperitoneal injection of 180 mumol sodium vanadate/kg body wt in mice inhibits the in vivo metabolism of drugs by the hepatic monooxygenase, as measured by exhalation of 14CO2 after treatment with appropriately labeled [14C]methacetin. Determinations of hepatic GSH, NADPH and NADH after vanadate injection show an initial and transient decrease of GSH (10 min, 20%), followed by a transient decrease of NADPH (30 min, 23%), followed by a decrease of NADH (40 min, 23% and 60 min, 26%). Rat liver organ spectrophotometry in the dual-wavelength mode shows an immediate response of the NAD(P)H level, which decreases transiently after addition of vanadate. Furthermore, EPR and AAS measurements indicate that vanadium occurs in the plasma in the oxidation states +IV and +V, whereas in intracellular compartments in liver and erythrocytes vanadium exists practically only in the +IV form (vanadyl). The duration of the inhibition for about 2 h coincides well with the transient concentration of vanadate in plasma, which decreases more rapidly than vanadyl. Maximal drug inhibition is associated with the phase of rapid formation of vanadyl in the liver. The experiments are in accordance with the hypothesis that vanadate inhibits the cytochrome P-450 dependent oxidative drug metabolism by diversion of reducing equivalents away from cytochrome P-450. Further evidence for such a hypothesis is provided by in vitro experiments in microsomes. Vanadate causes a dose dependent decrease of ethoxyresorufin deethylation which is reversible by the addition of NADPH.

Acetamides↗
PubMed1984

The use of the EEG for assessment of vigilance changes caused by beta-blockers.

The aim of this study was to investigate the changes of vigilance caused by beta-blockers. A recently developed method to measure the vigilance fluctuations, based on the EEG spectra, was employed together with self-rating. Repeated vigilance measurements were made in 20 healthy volunteers before and after administration of placebo, propranolol and metoprolol in random sequence. Both EEG analysis and self-rating confirmed that the vigilance level was significantly decreased after administration of beta-blockers compared to placebo. No significant difference between propranolol and metoprolol could be found. The results suggest that the decrease in systolic blood pressure after beta-blockade may be responsible for the drug-induced drowsiness. However, some of the observations made in the study can be interpreted as indirect proof that central mechanisms are also involved, and that both propranolol and metoprolol have sedative properties comparable to those observed with conventional psychotropic drugs.

Adult↗
PubMed1984

Blood ionic calcium response to hypocalcemia in the chicken induced by ethyleneglycol-bis-(B-aminoethylether) -N,N'-tetraacetic acid: role of the parathyroids.

Eight groups of cockerels were used to test an ethyleneglycol-bis-(B-aminoethylether)-N,N'-tetraacetic acid (EGTA) challenge as a possible means for estimating parathyroid function and responsiveness in birds. Intravenous injections of EGTA significantly depressed blood ionic calcium concentrations (hypocalcemia), and the recovery from this hypocalcemia was dependent upon the presence of parathyroid hormone (PTH). However, it also was demonstrated that a surge of PTH is not necessary for recovery from the EGTA-induced hypocalcemia. Therefore, in the bird, the EGTA challenge is a test of the ability of PTH target tissues (bone or soft tissues) to buffer ionic calcium in the blood. The EGTA challenge is not a quantitative means of testing parathyroid gland function or responsiveness.

Animals↗
PubMed1984

Blood ionic calcium responses of hens from thick-shell and thin-shell lines to ethyleneglycol-bis-(B-aminoethylether)-N,N'-tetraacetic acid injections.

Experiments were conducted on laying and nonlaying hens from genetically selected lines that produce thick (TK) or thin (TN) eggshells. At 44 weeks of age, TK layers exhibited significantly higher total plasma calcium concentrations than TN layers. Total plasma calcium concentrations were not significantly different between TK and TN layers at 80 weeks of age, reflecting an effect of aging on total plasma calcium. Intravenous injections of ethyleneglycol-bis-(B-aminoethylether-N,N'-tetraacetic acid (EGTA) were administered to TK and TN layers at 44 weeks of age and to TK and TN layers and nonlayers at 80 weeks of age. EGTA is a calcium chelating agent that creates hypocalcemia when injected intravenously. Laying hens of both lines and at both ages exhibited a similar degree of hypocalcemia during EGTA injections, and a similar rate of recovery to normocalcemia was noted after cessation of EGTA administration. Nonlayers were unable to recover from the EGTA-induced hypocalcemia. Because the pattern of calcium depression and recovery during and after the EGTA challenge has been shown to be associated with the capacity of parathyroid hormone-sensitive target tissues to buffer blood ionized calcium, it was concluded that the capacity to buffer ionized calcium by these target tissues is similar in TK and TN layers. However, nonlayers have a restricted capacity to buffer blood ionic calcium.

Animals↗
PubMed1983

Testing of chemicals by evaluation of their distribution and degradation patterns in an environmental standard system.

Due to the EC directive 79/831 of September 18, 1979, and the German law on hazardous substances, the submission of test data on physical--chemical properties of new substances is mandatory for their registration. These data are supposed to predict in which compartments (air, water, soil, vegetation) the substance will primarily accumulate if it enters the environment. To calculate the distribution of a substance in the environment compartments, different mathematical models have been developed by several working groups, but have not yet been verified in practical experiments. During a prolonged period, the distribution of substances in the environment compartments has been investigated by experiments in an environmental standard system; design and function are explained. Distribution and degradation patterns of 12 reference substances will systematically be investigated, covering a wide spectrum in regard to their physical--chemical properties. Up to now 7 substances have been investigated under standard conditions. The distribution patterns established in these experiments are presented and compared with those obtained mathematically by use of the presently discussed stationary distribution models and values for the physical--chemical properties of the tested substances. The time alterations observed in the distribution patterns are interpreted by a kinetic model which will be part of the calculation method which is presently being developed on the basis of the obtained test values. The good consistency of distribution patterns established by experiments with those established mathematically justifies the assumption that a reliable calculation method of distribution patterns can be submitted as soon as our current work will be finished.

Air Pollutants, Radioactive↗
PubMed1983

[Substrate specificity of phenoloxidase (EC 1.14.18.1)].

Using 10 microns thick cryostat-slides of spleen and gut from white rats the following substances (in 2 different concentrations) were tested as substrates for the enzyme phenoloxidase compared with dihydroxyphenylalanine: pyrogallic acid, resorcin, 2.4-dinitrophenol, tyraminhydrochloride, o-cresol, and epinephrine. Only pyrogallic acid and resorcin resulted in positive reaction. Resorcin showed a positive reaction only when the higher concentration is employed. The investigations show clearly that the detectable enzyme in gut, spleen, and oral cavity is a polyphenoloxidase, which occurs consequently not only in granulocytes.

Animals↗
PubMed1983

Computer graphics with computerized tomography for functional neurosurgery.

A computer graphics technique for computer-assisted stereotactic surgery is presented. The program is designed to aid the surgeon by presenting an on-line graphics display of stereotactic probes and electrodes superimposed on cross sections of the human brain stem. This technique simulates an otherwise blind surgical procedure on a graphics screen for use during surgery. An earlier system based around the DEC MINC-11 BA computer system has been used by the authors for the performance of stereotactic surgery with conventional ventriculography. This system has been upgraded and is now configured about an even more compact microprocessor-based hardware system with expanded graphics capabilities, which also allows its use with computerized tomography.

Brain Diseases↗
PubMed1983

Blood pressure of chickens selected for leanness or obesity.

Four lines of chickens selected for divergence in body weight followed by selection for obesity or leanness within each body weight line were used as a genetic model to determine the relationship of blood pressure and obesity. Forty females, 10 of each line, and 20 males, 10 from the heavy-weight obese and 10 from the light-weight obese, were used. Direct measurements of blood pressure were obtained from the left brachial artery of seven-month old birds. Systolic, diastolic, and mean blood pressures were recorded in this study. The systolic, diastolic, and mean blood pressure for the light-obese and light-lean females did not differ significantly; likewise, no difference was found for these three parameters in the heavy-obese and heavy-lean females. However, the blood pressures in the light-obese and light-lean lines were significantly higher than the heavy-obese and heavy-lean lines. Also, the blood pressures of the light-obese males were higher than those of the heavy-obese males; both male lines exceeded the females of the two respective lines.

Animals↗
PubMed1983

Double-blind comparative trial of trimethoprim/sulfamethopyrazine once daily vs erythromycin 4 X daily in patients with ENT infections.

Forty-two patients suffering from acute or recurrent ENT infections were given either 250 mg erythromycin 4 X daily or a new sulfamethopyrazine/trimethoprim combination (200 + 250 mg) once daily after a double loading dose on the 1st day, for 12 days on the average. Otitis media and externa, perichondritis, maxillary and frontal sinusitis were the most frequent clinical pictures. Assessment of efficacy was based on the course of objective and subjective clinical symptoms and, whenever possible, on bacteriologic findings. The new sulfa-trimethoprim combination showed activity similar to the reference drug, but it may have the advantage of a simpler dosage schedule.

Adolescent↗
PubMed1982

The inhibition of bovine and rat parotid deoxyribonuclease I by skeletal muscle actin. A biochemical and immunocytochemical study.

Rat and bovine parotid gland and pancreas contain deoxyribonuclease I (DNAase I) activities in different amounts. The DNAase I activity in tissue homogenates of bovine and rat parotid gland can be inhibited by addition of monomeric actin, as with the enzyme of bovine pancreas. The isolated DNAase I species from bovine and rat parotid gland differ in their molecular weights and also in their affinities for monomeric actin, being lowest for rat parotid DNAase I (5 X 10(6)M(-1). Antibodies raised against rat and bovine parotid and bovine pancreatic DNAase I can be used to study the subcellular localization of DNAase I in these tissues by indirect immunofluorescence. DNAase I was found to be confined solely to the secretory granules of the tissue from which it was isolated.

Actins↗