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Biomedical subjects

R Schulz

Publications and source records attributed to R Schulz.

At least 595 records · Page 33Linked to original sources
PubMed1979

Supersensitivity to opioids following the chronic blockade of endorphin action by naloxone.

Chronic treatment of guinea pigs with the narcotic antagonist naloxone (pellet implantation technique) caused an increased sensitivity to opioids of the electrically stimulated longitudinal muscle-myenteric plexus preparation of the ileum. This supersensitivity is associated with an elevation of the total number of opiate receptor binding sites in both the peripheral and the central nervous system.

Animals↗
PubMed1979

Specificity of opioids towards the mu-, delta- and epsilon-opiate receptors.

The potency of a number of opioid agonists have been determined on three different bioassays, the isolated guinea-pig ileum (GPI), the mouse vas deferens (MVD) and the rat vas deferens (RVD). With the exception of beta-endorphin, compounds with opioid activity on the GPI and the MVD exhibited considerably less or no activity on the RVD; the opiate receptor in this latter tissue being thus characterized as beta-endorphin selective ('epsilon-receptor'). A system of classification of opioids according to their relative relative affinities for particular opiate receptor types is given.

Animals↗
PubMed1979

[Rotavirus diarrhea in childhood].

Electron microscopy of 350 diarrhoeal faeces revealed Rotavirus-particles in 145 cases. All patients with Rotavirus-infections showed symptoms of acute gastroenteritis lasting 1 to 8 days. Additionally to diarrhoea most cases presented fever and vomiting. None of the patients showed toxicosis.

Child↗
PubMed1978

The opiate-like action of tilidine is mediated by metabolites.

The analgesic effect of tilidine in rats is completely antagonized by the narcotic antagonist naloxone. Radioreceptor assays revealed, however, that the main metabolites of tilidine, nortilidine and bisnortilidine, rather than tilidine exhibit affinity to opiate receptors. These findings were confirmed in studies using the electrically stimulated guinea pig ileum and the mouse vas deferens. Chronic tilidine administration to rats caused a considerable degree of physical dependence, which was expected from the ability of the intact animal to metabolize tilidine. In the isolated ileum from chronically morphinized guinea pigs, both nortilidine and bisnortilidine fully substituted for morphine in preventing induction of withdrawal, indicating dependence liability of these metabolites.

Analgesia↗
PubMed1978

Site of naloxone-precipitated opiate withdrawal dissociates from that at which apomorphine reinitiates this phenomenon.

The site of action of naloxone to induce jumping in morphine tolerant/dependent rats appears to be dissociated from structures where apomorphine initiates its action to reinduce jumping in previously withdrawn animals. These findings suggest that dopaminergic pathways do not directly affect the neuronal circuit involved in withdrawal jumping behavior, but instead exert a facilitatory influence on neurons that become supersensitive during the state of withdrawal. Thus, an increased response to apomorphine during naloxone-precipitated opiate withdrawal does not necessarily imply a specific supersensitivity of the dopaminergic system.

Animals↗
PubMed1978

Long-term effects of control and predictability-enhancing interventions: findings and ethical issues.

The long-term effects of participating in a field experiment on the effects of control and predictability-enhancing interventions are reported. Retirement home residents who had initially benefited from being exposed to a specific positive predictable or controllable event were assessed at three different intervals after the study was terminated. Health and psychological status data collected 24, 30, and 42 months after the study was terminated indicated no positive long-term effects attributable to the interventions. In fact, groups that had initially benefited from the interventions exhibited precipitous declines once the study was terminated, whereas groups that had not benefited remained stable over time. The theoretical and ethical implications of these data are discussed.

Aged↗
PubMed1978

[Investigations carried out to ascertain the dose-effect relationship of a BCG vaccine, strain 1331 Copenhagen, in neonates and young infants (author's transl)].

1405 neonates and infants were vaccinated with BCG Vaccine (strain 1331 Copenhagen) at five clinics in the Federal Republic of Germany. Doses in logarithmic increments from 22000 to 250000 VU (viable units)/0.1 ml were given by strictly intradermal injection. Carrying out the post-vaccinal tuberculin test by the MENDEL-MANTOUX technique, the dose-effect relationship could be demonstrated (Fig. 3). Conversion rates raised from 43% to 76% (Tab. 1); they are furthermore depending from the tuberculin dose and the assessment of the skin reaction. Tests with up to 50 I.U. of purified tuberculin were resulting in conversion rates over 90% for vaccination doses of 100 000 VU and more, any palpable infiltration regarding as a positive result (Fig. 4). The vaccine showed good safety in all concentrations employed concerning reactions at the site of injection. Lympnode enlargement, palable even 12 weeks postvacc., was common. In the course of the trial there was one case of suppurative lymphadenitis among the 262 children who were given the vaccine in the highest concentration (250000 VU). Subsequent trials revealed a rate of this complication in the 1:1000 range. The approval for the vaccine with 100000-300000 VU/dose has subsequently been given by the Federal Bureau for Sera and Vaccines.

BCG Vaccine↗
PubMed1977

Neuronal aspects of opiate dependence and tolerance in comparison to central depressants.

Some acute and chronic effects of opiates and of central depressants have been reviewed, in order that a comparison can be made between the actions of these drugs. Special emphasis has been given to opiate-induced changes at the neuronal level, which have been studied either by the direct microelectrophoretic application of drugs to single neurones or by application of drugs to the myenteric plexus/longitudinal muscle preparation of the guinea pig ileum. Available evidence suggests that chronic exposure of nervous tissue to opiates as well as to central depressants causes changes in neuronal excitability, which become apparent upon withdrawal of the drug. Although opiates and central depressants cause similar changes they appear to do so by different mechanisms. Such differences between the mode of action of opiates and central depressants may provide an explanation for the differing chronic effects of these drugs.

Animals↗
PubMed1977

Naloxone-precipitated withdrawal reveals sensitization to neurotransmitters in morphine tolerant/dependent rats.

Morphine tolerant/dependent rats were tested for their sensitivity to putative neurotransmitters or other receptor agonists injected intracerebroventricularly (i.c.v.) during naloxone-precipitated withdrawal. Dopamine, apomorphine, clonidine and serotonin were found to reinitiate withdrawal jumping behaviour when injected 30 min after naloxone. Dopamine and apomorphine also reinitiated jumping, but of a lesser intensity, when injected 3 h after naloxone-precipitated withdrawal. I.c.v. injection of acetylcholine or prostaglandin E1 failed to reinitiate withdrawal jumping. In addition, all the above substances failed to induce jumping behaviour in naive rats or in morphine tolerant/dependent rats before naloxone-precipitated withdrawal. Morphine tolerance and dependence therefore appears to be associated with changes in the sensitivity of the CNS to putative neurotransmitter substances. These changes are best demonstrated during the sudden termination of opiate action that is caused by administration of naloxone.

Animals↗