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Biomedical subjects

J Schmidt

Publications and source records attributed to J Schmidt.

At least 793 records · Page 44Linked to original sources
PubMed1980

[Modification of chemoreactive properties of neurons in the neocortex and hippocampus under the effect of electric stimulation of locus coeruleus].

Based on the findings of alterations in the chemoreactivity of neurons under conditioning and its possible significance for the formation of transient neuronal junctions, the authors investigated the influence of electrical stimulation of the Locus coeruleus upon the transmitter sensitivity of cortical and hippocampal neurons. The majority of neurons showed immediately after stimulation of the Locus coeruleus a different reaction to microiontophoretic application of acetylcholine, dopamine and glutamate than under normal conditions. Obviously there must have occurred qualitative changes because a superposition effect of the reactions following stimulation of the Locus coeruleus and application of the substances has rarely been observed. The release of noradrenaline provoked by the stimulation of the Locus coeruleus evidently leads to qualitative changes in the neurone texture, which may occur both inter- and intraneuronally.

Acetylcholine↗
PubMed1980

[Changes of neuronal activity in the rat's hippocampus under long-term treatment with desipramine].

Long-term treatment of rats with the antidepressive desipramine increase in the hippocampus the number of neurons with low spontaneous discharges and affects the animals' response to microiontophoretically applied noradrenalin. Additional acute administration of desipramine causes, after long-term treatment with the antidepressive, a stronger increase in noradrenalin induced inhibition of the firing rates as compared with controls.

Action Potentials↗
PubMed1980

[Conservative surgical treatment for large maxillary cysts. Some comments on technique (author's transl)].

Conservative surgical treatment for large maxillary cysts consists of releasing the cystic wall of the bony cavity without destroying the pulp of the teeth which have apices close to the operated cavity (unless the tooth is already dead). The vestibular approach is through one or two orifices and is as small in size as possible. This technique generally allows conservation of the vitality of the largest number of teeth and avoids postoperative collapse.

Bone Cysts↗
PubMed1980

[Virological diagnostics of acute respiratory diseases].

Considering mainly practical aspects, a review of available methods of virological diagnosis of acute respiratory diseases is given. The first part contains the elements of virological diagnostics, especially a description and valuation of rapid detection of virus using fluorescent antibodies, and of haemadsorption technique for rapid diagnosis. Moreover, methods of viral isolation (cell cultures, embryonated eggs), conventional serological tests (CFR, HAIT, NT), and recent, not yet generally applied serological techniques (passive haemagglutination, indirect fluorescent antibody technique, haemadsorption inhibition test, radial immunodiffusion, radial immunohaemolysis, radio immune assay, enzyme linked immune assay) are described and valued as diagnostic tools in viral diseases of respiratory system. The second part deals with the specific diagnostics of infections by influenza, parainfluenza, RS-, adeno-, corona-, and rhinoviruses. Special instructions for the application of available tests and for the interpretation of results are given.

Acute Disease↗
PubMed1980

[Frequency of transfusion in lung resections (author's transl)].

Blood-transfusions are affected with considerable risks and undesirable reactions, for that reason the application of whole blood is indicated strictly. The comparison of transfusions in patients having undergone a lung resection showed a decrease in transfusions about 50 per cent in a period of 10 years. The reduction of transfusions is the result of an increased use of blood substitutes. Advantages and possibilities of hemodilution are discussed. The application of whole blood depends on preoperative hematocrit and calculated blood volume.

Adolescent↗
PubMed1980

[Effect of social isolation on the transmitter sensitivity of striatal and hippocampal neurons of the rat].

Rats kept in isolation for 3 months from the 4th week onward show increased sensitivity of striatal neurons for dopamine and acetylcholine, as well as of the hippocampal neurons for noradrenalin administered microiontophoretically, in comparison to animals maintained collectively. The results are discussed as reflecting a supersensitivity of central dopaminergic and noradrenergic receptors caused by the social isolation.

Acetylcholine↗
PubMed1980

[Central depletion of transmitters by reserpine and motor behavior in the rat (author's transl)].

Reserpine treatment depletes the catecholamine content in diverse parts of the brain differently. Restoring proceeds slowly with different velocities. Dopaminergic areas tend to a faster repletion than noradrenergic ones. During long-term depletion a recovery of motoric behaviour occurs. This adaptive process is not correlated with the dopamine level in caudate nucleus. The latter depends on the dosage schedule and fails in developing adaptive changes to chronic reserpine administration.

Adaptation, Physiological↗
PubMed1980

Interaction at the synaptic level of fusaric acid with neurotransmitters.

Fusaric acid (FA) is shown to induce inhibition of noradrenaline and dopamine uptake in synaptosomes from rat hypothalamus and corpus striatum. The basal overflow of noradrenaline and dopamine from "brain stem" and corpus striatum slices is stimulated by FA. While this influence of FA on noradrenaline release is further enhanced by other stimuli (raised K+ concentration or electrical stimulation), no comparable effect can be observed concerning dopamine release. The data show that FA which is known as a potent dopamine-beta-hydroxylase inhibitor of high specificity exerts also marked effect in the central nervous system by interference with other synaptosomal functions.

Animals↗
PubMed1980

[Surgical therapy of chronic arterial obstructions of the lower extremities in elderly patients].

The aim of this study was to determine whether arterial reconstructions in old age carry an acceptable risk and are reasonable as far as long term results are concerned. The operative mortality was 3,4% for reconstructions distal to the inguinal ligament and 20.5% for reconstructions in the aorto-iliac region. Limb amputations were fraught with a very high mortality of 38.9%.

Amputation, Surgical↗
PubMed1980

[Effects of striatum stimulation and micro-iontophoretically applied dopamine and acetylcholine on the neuronal activity of the globus pallidus].

Alert, myorelaxed rats were used to study the influence of electrical stimulation of the stiatum and micro-iontophoretic application of dopamine and acetylcholine upon the discharge activity of neurons of the Globus pallidus. Out of 55 pallidal neurons, 25 responded to striatum stimulation with an initial inhibition and subsequent irritation, and 21 with an irritation-inhibition sequence. 40% of the neurons were dopamine-sensitive (23% irritation, 77% inhibition) and 38% choline-sensitive (63% inhibition, 37% irritation). 25% of the dopamine-sensitive neurons were at the same time choline-sensitive. There was no direct relation demonstrable between the effects of striatum stimulation and micro-iontophoretic application of acetylcholine or dopamine.

Acetylcholine↗
PubMed1980

Echocardiography [UCG] in hypertension. Myocardial performance comparison with controls and sportsmen.

Thanks to a number of parameters available, mean velocity of fibre shortening (mVCF), fibre shortening (FS%), ejection fraction (AF), stroke volume (SV), enddiastolic volume (EDV), echocardiography (UCG) is a non-invasive and well reproducible technique for examining the functioning of the heart. The UCG results obtained for 93 pre-treated male non-congestive hypertensives were compared with those obtained for 75 normotensives and 21 endurance sportsmen. In spite of the increasing degree of HT (WHO standards), the cases studied did not show a statistically significant decrease in the myocardial function. This study reveals that in general the heart of a hypertensive does not yet show at rest an overall functional loss. Compared with the left ventricular mass, however, a trend towards reduced performance can be seen, particularly when compared with sportsmen having a hypertrophy of a similar degree.

Adult↗
PubMed1979

[Intolerance to acetylsalicylacid and food additives in patients suffering from recurrent urticaria (author's transl)].

Ninety patients suffering from recurrent urticaria were orally exposed to 500 mg acetyl salicylic acid (ASA). 36.6% proved to be ASA intolerant in this group. 26 ASA-positive and 18 ASA-negative probands were selected to take part in an additional provocation test with 8 different food additives (preservative and colouring matters). Altogether 31 tests sheets were exaluated. Urticarial reactions were seen after administration of p-hydroxybenzoic acid methylester (5), p-hydroxybenzoic acid propylester (6), benzoic acid (9), sodium benzoate (6), tartrazine (6). Ponceau rouge (5) and indigo carmine (3). Detailed research was carried out on the occurrence of the tested substances. With a diet avoiding salicylates, benzoates and colouring matter 20% of these patients recovered spontaneously and became symptom-free, whilst a further 55% of cases showed marked improvement.

Adult↗
PubMed1979

Resonance Raman study of flavins and the flavoprotein fatty acyl coenzyme A dehydrogenase.

The resonance Raman (RR) spectra of FMN, FAD, FAD in D2O, and 7,8-dimethyl-1, 10-ethyleneisoalloxazinium perchlorate have been obtained by employing KI as a collisional fluorescence-quenching agent. The spectra are very similar to those obtained recently by using the CARS technique to eliminate fluorescence. Spectra have also been obtained for several species in which flavin is known to fluoresce only weakly. We report RR spectra of protonated FMN, FMN semiquinone cation, the general fatty acyl-CoA dehydrogenase, and two "charge-transfer" complexes of fatty acyl-CoA dehydrogenase. Tentative assignment of several vibrational bands can be made on the basis of our flavin spectra. RR spectra of fatty acyl-CoA and its complexes are consistent with the previous hypothesis that visible spectral shifts observed during formation of acetoacetyl-CoA and crotonyl-CoA complexes of fatty acyl-CoA dehydrogenase result from charge-transfer interactions in which the ground state is essentially nonbonding as opposed to interactions in which complete electron transfer occurs to form FAD semiquinone. The only significant change in the RR spectrum of FAD on binding to enzyme occurs in the 1250-cm-1 region of the spectrum, a region associated with delta N--H of N-3. The position of this band in fatty acyl-CoA dehydrogenase and the other flavoproteins studied to date is discussed in terms of hydrogen bonding between flavin and protein.

Acyl-CoA Dehydrogenases↗
PubMed1979

Starch metabolism in Pseudomonas stutzeri. I. Studies on maltotetraose-forming amylase.

The extracellular maltotetraose-forming amylase of Pseudomonas stutzeri was purified to homogeneity by a combination of affinity and hydroxyapatite chromatography. Sodium dodecyl sulfate-gel electrophoresis indicated that the oligomeric enzyme contains two different subunits with molecular weights of 48 000 and 58 000. Cross-linking studies using dimethyl suberimidate have demonstrated that the native enzyme consists of dimers. Seven isozymes of the amylase have been identified after polyacrylamide gel electrophoresis and amylose-digestion zymograms. The amylase of Ps. stutzeri is known to produce maltotetraose from linear and branched alpha-glucans by an exomechanism. The relatively high conversion rate of starch (75% hydrolysis), and the hydrolysis of cross-linked blue starch by this amylase indicate that the enzyme can cleave its substrates also by an endomechanism. Further strong evidence for an endomechanism was obtained from the action of the amylase on maltotetraose units which are located within the pullulan molecule. Dextran, pullulan, and maltotetraose are compeititve inhibitors. EDTA caused reversible inactivation. Amylase activity could be restored by addition of Ca2+. Heavy metals are inhibitory.

Amylases↗