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Biomedical subjects

E Schubert

Publications and source records attributed to E Schubert.

At least 73 records · Page 4Linked to original sources
PubMed1976

[Systolic and diastolic load of right heart and right bundle block].

Analysing the Ecg and VCG of 818 subjects, healthy or with different congenital and acquired cardiopaties, the frequency of right bundle branch block (RBBB) is established to decrease with the increase in age of children, and is observed to be 8.9% in healthy adults. The right bundle block is observed in 82.5% of the patients with atrial septal defect and quite often in patients with right ventricle tension loading, gradually decreasing with the level of the left ventricle loading, as well as with the development of extreme right ventricle hypertrophy. Out of 50 experiments with dogs with acute and chronic right heart tension loading it is evident that the number of certain and marginal (uncertain) cases with RBBB steadily increases. At the same time this increase cannot be connected with the type of loading, in dogs in which dilatation of the right ventricle is presented as well as in others with light or marked hypertrophy. Besides, under the same conditions and durations of loading some hearts exhibit RBBB, while others do not. What has been stated before gives enough grounds to accept that RBBB in healthy subjects, as well as in patients with congenital and acquired cardiopaties manifests the electromotive tension (EMT) of persistent from foetal and children-age more pronounced physiological hypertrophy (as normal variant) of the basal part of the right ventricle. Whether the picture of RBBB is retained, pronounced or disappears is determined by the correlation between the quantity and the time-manifestation of EMT of the left ventricle and of the corps part of the right ventricle.

Adolescent↗
PubMed1976

The influence of theophylline on the motility and the cyclic 3',5'-AMP content in the pregnant and non-pregnant rat uterus in vitro.

The tension developed by muscle strips obtained from pregnant and non-pregnant rat uteri and uterine cyclic 3',5'-AMP was measured in the presence of increasing amounts of theophylline. In the pregnant uterus the initial tension was elevated by 112% and the tissue level of cAMP by 59% as compared to the normal organ. 1 mM theophylline relaxed the normal uterus by 81% and the pregnant uterus by 36% without any change in the cAMP concentrations. Higher amounts of theophylline (3-10 mM) able to relax the pregnant uterus completely also increased uterine cAMP in a dose dependent manner. It seems likely that the effect of high amounts of theophylline is mediated by cAMP, which, however, is not involved in the action of low (therapeutic) doses of the drug.

Animals↗
PubMed1975

[Mode of action of bisacodyl (dulcolax) on isolated muscles of human colon (author's transl)].

The effects of bisacodyl (4,4-diacetyl-bis-hydroxyphenyl-pyridyl-(2)-methan, Dulcolax) on the tone of isolated muscle strips of human colon were examined. Maximal contractions achieved by 10 mug/ml of bisacodyl were quite comparable to those due to 1 mug/ml of acetylcholine, 1 mug/ml of histamine and 0.5 mug/ml of nicotine, respectively. However, peak contractions were attained with a greater latency and could not be prevented by the anticholinergic agent atropine, the H1-antihistaminic diphenhydramin or tetrodotoxin blocking axonal conduction. On the other hand, pretreatment with verapamil -- antagonizing calcium influx into the muscle cell -- abolished bisacodyl effects. These results provide evidence for a direct action of bisacodyl on smooth muscle cells of human colon.

Acetylcholine↗
PubMed1975

Relations between the effects of histamine, pheniramin and metiamide on spontaneous motility and the formation of cyclic AMP in the isolated rat uterus.

Histamine (5 X 10(-6) to 10(-3) M) depressed the spontaneous motility of the isolated rat uterus in a dose-dependent manner. Under these conditions uterine cyclic AMP was raised up to 92%. Both effects, uterine relaxation and cyclic AMP accumulation after 2 min could be inhibited dose dependently by the H2-antihistaminic compound metiamide (1.7 X 10(-6) M to 1.7 X 10(-4) M). By contrast, the H1-antagonist pheniramin (4.4 X 10(-5) M) was ineffective. It was concluded that the histamine-induced inhibition of rat uterine motility is mediated by cyclic AMP which is formed in response to stimulation of H2-histaminergic receptors.

Animals↗
PubMed1975

A comparison between noninvasive and bloody methods for use in the continuous estimation of cardiac contractility.

Simultaneous measurements of the blood pressure in arteria carotis with a catheter device and a new noninvasive continuously recording method were carried out in 7 rabbits with a chronically isolated arteria carotis loop. Results show good correspondence between both methods for pulse curve and blood pressure over a long period and a wide range,as well as good reproducibility. An absolute calibration for the noninvasive method is impossible. The new method is quite suitable for studying the dynamics of pressure pulse and pressure behavior.

Animals↗
PubMed1975

Analysis of the motor effects of 13-norleucine motilin on the rabbit, guinea pig, rat, and human alimentary tract in vitro.

Motor effects of 13-norleucine motilin (13-Nle-M), a synthetic analog of motilin and biologically equivalent to the natural polypeptide, on the rabbit, guinea pig, rat, and human alimentary tract were investigated in vitro. Whereas guinea pig and rat preparations proved refractory to 13-Nle-M action, muscle strips of the stomach and upper small intestine from rabbits and man were highly sensitive to 13-Nle-M, contractile responses being elicited with concentrations of less than 2 times 10-minus 9 M. Although circular muscle from rabbit colon responded to 13-Nle-M, Taenia coli preparations were unaffected by the polypeptide; in man, the reverse was observed. Gallbladder, uterine, and vascular smooth muscle were unresponsive to 13-Nle-M. Pharmacological analysis revealed that the effects of 13-Nle-M on the gastrointestinal muscle are not mediated via nervous pathways: ganglion blockade by hexamethonium, blockade of axonal conduction by tetrodotoxin, or anticholinergic action by atropine failed to affect 13-Nle-M actions. It was therefore concluded that 13-Nle-M caused contractions by stimulating receptors on or in the muscle cell. By use of the antihistaminic pheniramine, histamine receptors could be differentiated from the site of 13-Nle-M action. As the contractile response to 13-Nle-M was abolished by the Ca++ antagonistic compound verapamil, a role for 13-Nle-M in the transport of Ca++ to the cytosol of intestinal smooth muscle might be considered.

Acetylcholine↗
PubMed1975

[The effect of the tidal volume on the sinus arrhythmia of the heart].

The sinus arrhythmia of the human heart was investigated in its relation to the tidal volume under resting conditions in the course of the day, in voluntarily changed tidal volume, under atropine medication and during physical work. In resting conditions it was found that nearly 40% of the sinus arrhythmia is of respiratory origin, and that no respiratory influence is demonstrable any longer at sufficient doses of atropine. Under physical load, the sinus arrhythmia is diminished in spite of the enlarged tidal volume. In this case, an additional smoothing influence to the sinus arrhythmia has to be assumed.

Adult↗
PubMed1975

[The mode of action of bisacodyl on the smooth muscle of the small and the large intestine of the guinea pig].

4,4'-Diacetoxy-diphenyl-(pyridyl-2)-methan (Bisacodyl, Dulcolax, 12--240 mug/ml) was shown to initiate dose-dependently contracile responses in the guinea pig isolated terminal ileum and taenia coli (a preparation of pure longitudinal muscle fibers). In contrast to muscle contractions induced by 1 mug/ml acetylcholine (ACh) and 1 mug/ml histamine, respectively bis-acodyl-induced contractile responses were antagonized neither by the anticholinergic agent atropine (6 mug/ml) nor by the antihistaminic compound pheniramine (6 mug/ml). On the other hand, bisacodyl inhibited contractile responses induced by ACh or histamine in a dose-dependent manner. The possibility that bisacodyl-induced contractions were due to a fall in cyclic 3,5-AMP level was excluded by estimation of endogenous cyclo-AMP. Since exogenous cyclic 3,5-AMP (which should possess calcium-antagonistic properties in smooth muscle) as well as verapamil (a calcium inhibitor) inhibited bisacodyl-induced contractions, a site of action on the calcium-dependent contractile system of the smooth muscle cell was discussed. Furthermore, bisacodyl should diminish the sensibility of the contractile system to other contractile compounds (ACh, histamine).

Acetylcholine↗