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Biomedical subjects

H Stöhr

Publications and source records attributed to H Stöhr.

At least 55 records · Page 3Linked to original sources
PubMed1984

The chronically stimulated muscle as an energy source for artificial organs. Preliminary results of a basic study in sheep.

In 5 adult sheep the psoas muscle of one side was electrically stimulated through the muscle nerves with an implantable stimulation unit for more than 5 weeks. In the final experiments the isometric tetanic tension of the stimulated muscles was reduced to 50-70% of the contralateral normal muscle. The use of only 15 Hz as a stimulation frequency led to a transformation of the originally fast muscle into a slow muscle with more resistance to fatigue. Future application of the chronically stimulated psoas muscle for driving artificial organs is discussed.

Animals↗
PubMed1984

Encephalotropic and psychotropic effects of intravenous buflomedil in the elderly: double-blind, placebo-controlled pharmaco-EEG and psychometric studies.

In a double-blind placebo-controlled study, the encephalotropic and psychotropic properties of intravenously administered buflomedil--a new vasoactive drug--were studied in 10 elderly volunteers in their 60s by means of quantitative EEG and psychometric analyses. At weekly intervals the patients received randomized (latin square design), single, intravenous doses of placebo, 50 mg, 100 mg and 200 mg buflomedil as well as 2000 mg piracetam as reference substance. EEG recordings and the monitoring of blood pressure, heart rate and side-effects were carried out at hours 0, 1, 2, 4, 6 and 8. Psychometric tests were performed at hours 0, 2, 4, 6 and 8. Computer-assisted spectral analysis of the EEG demonstrated that buflomedil exerted a significant effect on the central nervous system (CNS) as compared with placebo, characterized by a decrease of delta and theta, increase of alpha and alpha-adjacent beta activity as well as by an acceleration of the centroid of the alpha activity and also of the total activity. 2 g piracetam induced the same type of changes only at the end of the recording day. These quantitative EEG changes have been previously observed after several antihypoxidotic/nootropic drugs and indicate an improvement in vigilance in the sense of Head. Treatment-efficacy calculations demonstrated that 200 mg buflomedil was the most CNS-effective substance followed by 100 mg and 50 mg buflomedil and 2 g piracetam. Time-efficacy calculations showed that the encephalotropic effects were already marked in the 1st hour after i.v. application, decreased to a low in the 4th hour and subsequently increased again to reach a maximum in the 8th hour. In contrast, 2 g piracetam induced CNS changes which increased from the 1st throughout the 6th hour to show only a slight decline thereafter. The hysteresis between pharmacodynamic and pharmacokinetic findings is discussed. Psychometric investigations demonstrated that after 50 mg buflomedil i.v. there was a significant improvement as compared with placebo in cognitive function based on the Pauli test as well as an increase in correct reactions in the alphabetical reaction test. Doses of 100 mg buflomedil also produced an improvement in the Pauli test, attenuated errors in the reaction time task, improved complex reaction on the Vinnese Determinationsgerät, increased CFF but also errors in the concentration test.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1983

[Classification and determination of the pharmacodynamics of a new tetracyclic antidepressive agent, pirlindol, using pharmaco-EEG and psychometry].

In a double-blind placebo-controlled study the encephalotropic and psychotropic properties of a new tetracyclic pyrazino-indole derivative were studied in 10 normal volunteers. They received, randomized at weekly intervals, single oral doses of placebo, 75 mg, 150 mg and 225 mg pirlindol, as well as 75 mg imipramine, 20 mg tranylcypromine and 150 mg nomifensine as reference drugs. Pharmaco-EEG, psychometric and physiological data were obtained at the hours 0, 1, 2, 4, 6 and 8 after oral administration. Digital computer period analysis of the EEG demonstrated moderate CNS effects with pirlindol as compared with placebo. Its pharmaco-EEG profile, especially after higher dosage (150 and 225 mg), was characterized by a decrease in delta and theta activity, an increase in alpha activity and a delta and theta activity, an increase in alpha activity and a decrease in beta activity, as well as by an attenuation of the average frequency and frequency deviation and a trend towards an augmentation of the amplitude and amplitude variability. This profile is typical for antidepressants of the desipramine type and was also observed in our present study after 150 mg nomifensine and (although less markedly) and 20 mg tranylcypromine. 75 mg pirlindol induced, however, changes characterized by a concomitant increase in slow and superimposed fast activities and by a decrease in alpha activity. These alterations were described previously as typical for antidepressants of the imipramine type, and were also noted after 75 mg imipramine in the present study. Time-efficacy calculations showed the maximal pharmacodynamic effect of pirlindol in the 4th to 6th hour, of 75 mg imipramine in the 2nd hour, of 20 mg tranylcypromine in the 4th hour and of 150 mg nomifensine in the 6th hour. Dose/treatment-efficacy calculations identified in the 1st and 2nd hour post drug 75 mg imipramine as the most CNS-effective drug, in the 4th and 6th hour 150 mg pirlindol and in the 8th hour 225 mg pirlindol. Psychometric investigations showed only slight changes after pirlindol, reaching only rarely the level of statistical significance (improvement in attention after 225 mg pirlindol, decrease in tapping after 75 and 150 mg pirlindol, as well as attenuation of the complex reaction after all 3 doses of pirlindol). Concentration, attention-variability, psychomotor activity, CFF, after effect (Archimedean spiral), reaction time, mood and affectivity were not significantly altered as compared with placebo. Pulse, systolic and diastolic blood pressure did not show any clinical relevant changes either.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1982

Objective measures in determining the central effectiveness of a new antihypoxidotic SL-76188: pharmaco-EEG, psychometric and pharmacokinetic analyses in the elderly.

In a double-blind, placebo-controlled, cross-over study, the blood levels as well as the encephalotropic and psychotropic properties of SL-76188 - a new molecule of the hexahydrocanthinone series - were studied in 10 elderly subjects by means of quantitative EEG and psychometric analysis. They received randomized and in weekly intervals single oral doses of 100, 175 and 250 mg SL-76188, placebo and 20 mg D-amphetamine as the reference substance. Blood sampling, EEG recordings and the monitoring of blood pressure, heart rate and side effects were done at 0, 1, 2, 4, 6 and 8 h. Psychometric tests were performed at 0, 2, 4, 6 and 8 h. HPLC demonstrated that the drug was rapidly absorbed as the peak plasma levels were found within the first 2 h. A dose-dependent kinetic profile was observed based on exponential correlations between dose and peak plasma levels and AUC. Computer-assisted spectral analysis of the EEG showed a significant CNS effect as compared with placebo. The attenuation of delta and theta activity, increase of alpha and certain beta activities and the acceleration of dominant frequency suggested an improvement in vigilance. This was reflected behaviorally by an improvement in concentration, attention variability, complex reaction and mood, especially in the higher dosage range. The reference substance 20 mg D-amphetamine exhibited more psychostimulatory properties, which were also observed in regard to the side effects. Blood pressure and heart rate increased only with D-amphetamine as compared to placebo. Finally, the relationship between kinetic and dynamic data was explored. An increase in pharmacodynamic changes on the descending slope of the kinetic curve resulted in a so-called 'hysteresis loop', the implication of which is discussed.

Aged↗
PubMed1979

[The research programme "Artificial Heart" at the 2nd Department of Surgery, University of Vienna: a ten year review (author's transl)].

The experimental and clinical results are presented of the research programme "Artificial Heart" carried out by the 2nd Department of Surgery, University of Vienna. In particular, an assessment of the clinical experience in 177 patients with the intra-aortic balloon pump is documented and it is concluded that only limited cardiac support is possible by this pump. In view of this fact more efficient methods of mechanical circulatory support, such as the interaortic auxilliary ventricle, the aortic "Windkessel" ventricle with guiding balloon, and two types of ventriculo-aortic bypass ventricle were tested with regard to their haemodynamic and long-time efficacy. The transatrio-aortic auxilliary ventricle (E-LVAD) was also clinically tested in 11 patients. In conclusion the problems of total mechanical heart replacement are discussed.

Animals↗
PubMed1975

[On the phenolic acids of vegetables. III. Hydroxycinnamic acids and hydroxybenzoic acids of root vegetables (author's transl)].

In carrots, celeriac, scorzoneras, and horse radish caffeic acid, in small radishes p-coumaric acid, in beets ferulic acid and in radishes probably ferulic acid is dominating after hydrolysis. The contents of phenolic acids in the roots are much smaller than in the corresponding leaves. Carrots, small radishes, horse radish and partially scorzoneras show higher concentrations of phenolic acids in outer tissue layers. In contrary to hydroxycinnamic acid derivatives the contents of hydroxybenzoic acid derivatives (p-hydroxybenzoic, vanillic, salicylic and gentisic acid) mostly were small. Partially hydroxycoumarins (aesculetin and scopoletin) identified.

Caffeic Acids↗
PubMed1975

The phenolics of fruits. VII. The phenolics of cherries and plums and the changes in catechins and hydroxycinnamic acid derivatives during the development of fruits.

Quantitative data of hydroxycinnamic acids, hydroxybenzoic acids and hydroxycoumarins (after hydrolysis of derivatives) and of catechins are given. -Large quantities of catechins and hydroxycinnamic acid derivatives are found in the young fruit. Related to mg per kg fresh weight these concentrations soon decline sharply, especially during the progressive growth of the fruits. Related to mg per fruit, the concentrations of catechins increase progressively with fruit development, showing a loss when reaching maturity. The concentrations of hydroxycinnamic acids increase in a similar manner, but show in part a remarkable loss when examined after removal of the harder seeds.

Benzopyrans↗
PubMed1975

[V. The phenolics of strawberries and their changes during development and ripeness of the fruits (author's transl)].

16 strawberry varieties contained ca. 10--70 mg (+)-catechin per kg freshweight, frequently up to 10 mg (-)-epicatechin, seldom (+)-gallocatechin and never (-)-epigallocatechin. The phenolic contents after hydrolysis were up to ca. 10 mg caffeic acid, ca. 10--15 mg p-coumaric acid, ca. 10--35 mg 4-hydroxybenzoic acid, up to 6 mg protocatechuic acid and ca. 10--40 mg gallic acid per 1000 g freshweight. From "Senga Sengana" ca. 10 mg/kg methyl gallate and ellagic acid were isolated. Salicylic acid, gentisic acid and vanillic acid were found in traces (1 mg/kg). The concentrations of all the examined phenolic acids, relating to the whole fruit (mg per fruit) increased, and, relating to fresh weight (mg per kg) decreased during the growth of the fruits with exception of 4-hydroxybenzoic acid. This acid appeared only in a relatively late stage of the fruit. The changes in catechins were similar. In the ripe fruit the catechin level was reduced a little.

Benzopyrans↗