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P Propping

Publications and source records attributed to P Propping.

At least 217 records · Page 12Linked to original sources
PubMed1986

Genetic studies at the receptor level: investigations in human twins and experimental animals.

In receptors, as in enzymes, quantitative as well as qualitative genetic variation may exist. Studies in inbred strains of mice have shown for various receptors that the receptor density as determined by Bmax values is under genetic control. In healthy adult twins we have shown that the density of alpha-adrenoceptors on platelets is also influenced by genetic factors, since monozygotic twins were much more similar to one another than dizygotic twins. However, Bmax values are up-regulated and down-regulated by endogenous neurotransmitters and pharmacologically active agents. Thus, receptor densities are under considerable regulatory influences. Bmax values therefore reflect regulatory mechanisms rather than innate characteristics of the receptor protein. In another twin study we failed to find evidence for a genetic influence on the density of imipramine-binding sites on platelets. Since qualitative variation (polymorphism) is well known in enzymes, it may also apply to receptors. Qualitative differences in the receptor protein within one species would be of particular interest because of possible functional implications. As a first approach we examined central benzodiazepine receptors by photoaffinity labelling and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. A comparison of fish, frog, chicken, mouse, rat and calf led to the detection of variation between species. Investigations in five inbred mouse and rat strains have not so far revealed genetic variation in benzodiazepine receptors. Nevertheless variation may be detectable by more sensitive methods such as peptide mapping after limited proteolysis or two-dimensional electrophoresis.

Affinity Labels↗
PubMed1986

The influence of low arylsulfatase A activity on neuropsychiatric morbidity: a large-scale screening in patients.

A total of 1728 patients consecutively admitted to a neuropsychiatric hospital and 379 chronically ill inpatients were examined for activity of arylsulphatase A (ASA) in leucocytes. A further 519 healthy individuals served as controls. We did not find evidence for the involvement of low ASA activity in chronic patients. The consecutive admissions showed a slight preponderance in the lower ASA activity classes. This activity range covers persons heterozygous for ASA deficiency alleles. The data are compatible with the hypothesis that carriers of low ASA activity alleles are at a slightly higher risk for neuropsychiatric disorders.

Alleles↗
PubMed1986

Benzodiazepine receptor subunits in avian brain.

Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of the photoaffinity-labeled benzodiazepine receptor in duck brain, two equally intensive bands of relative molecular masses of 53,000 and 54,000 were observed, thus being identical to the subunit pattern previously described for chicken brain. An attempt was made to characterize further the avian subunits. Comparison of the fluorographic subunit pattern in cerebellum and telencephalon revealed a pronounced quantitative heterogeneity. Addition of ethyl beta-carboline-3-carboxylate resulted in the selective inhibition of the 53,000 subunit. These results are compared with the mammalian subunit pattern in the corresponding brain regions. The findings are discussed in view of the apparent contradiction between the existence of regional heterogeneity when photoaffinity labeling is applied and its lack when monoclonal antibodies are used.

Affinity Labels↗
PubMed1984

3H-imipramine binding in human platelets: a study in normal twins.

3H-imipramine binding was determined in freshly prepared intact platelets from 17 monozygotic (MZ) and 15 dizygotic (DZ) twin pairs, all of them male, adult, drug-free, and healthy volunteers. Sixteen males served as controls for determination of intraindividual variation of binding parameters. Both MZ and DZ twin pairs exhibited high intraclass correlations of Bmax values, but DZ twins were nearly as similar as MZ pairs. Interindividual variation of binding parameters is not large enough to reveal a significant genetic control.

Adult↗
PubMed1984

Epinephrine-induced platelet aggregation. A twin study.

A study in healthy adult male twin pairs (17 MZ, 15 DZ) was devised to examine the genetic influence on epinephrine-induced platelet aggregation. Intraclass correlations of for MZ, 0.43 for DZ, and 0.61 for repetitive experiments in the same subjects point to the influence of genetic factors. The antagonizing effect of phentolamine on platelet aggregation did not prove to be under genetic control. There was no significant correlation between epinephrine concentrations which induce half-maximal aggregation and number of alpha-adrenergic receptors as measured by 3H-yohimbine binding. In one MZ twin pair concordantly, and also in two unrelated persons, epinephrine was unable to induce complete platelet aggregation. This phenomenon is not related to the number of alpha-adrenergic binding sites on platelets.

Epinephrine↗
PubMed1983

Genetic disorders presenting as "schizophrenia". Karl Bonhoeffer's early view of the psychoses in the light of medical genetics.

There is overwhelming empirical evidence for the influence of genetic factors in the etiology of schizophrenic psychoses. An appreciable and still increasing number of exogenous factors have been known for decades that are capable of inducing psychoses that present as "schizophrenia" or are more or less similar to it. In this article, genetic disorders--chromosomal abnormalities and Mendelian diseases--are summarized that may be associated with such psychoses. These disorders frequently but not necessarily exhibit additional physical symptoms. Although the majority of schizophrenic psychoses can so far not be explained by exogenous factors or well-defined genetic disorders, the proportion of these etiologies among all cases may be higher than presumed so far, because they evade detection. Data from the literature are discussed in the light of Karl Bonhoeffer's early concept of exogenous reaction types and modern medical genetics.

Diagnosis, Differential↗
PubMed1983

Genetic control of adrenergic receptors on human platelets. A twin study.

It was examined whether genetic factors are involved in the expression of alpha-2 adrenergic receptors on human platelets, as measured with 3H-yohimbine as ligand. The twin series comprised 17 monozygotic and 15 dizygotic adult, healthy, male, drug-free twin pairs. For control of intraindividual and interassay variation, 13 unrelated pairs of subjects were examined. Bmax values for 3H-yohimbine binding (range 91-305 fmol/mg protein) proved to be under considerable genetic control; this was not the case for KD values. Different possible genetic mechanisms are discussed.

Adult↗
PubMed1983

Is there an increase of reproductive rates in schizophrenics? II. An investigation in Nordbaden (SW Germany): methods and description of the patient sample.

For an investigation on the question of whether fertility rates of schizophrenics have been increasing in recent times, two cohorts of patients were defined on an epidemiological basis. The patients were first admissions during either 1949-50 (n = 183) or 1965-67 (n = 228). The conditions of case definition as well as their demographic and psychiatric characteristics are described. These data are necessary for the evaluation of reproductive rates observed in the patient sample. Furthermore, the two cohorts of patients may be of general interest, because they comprise patients first admitted to a hospital who were completely ascertained in a certain region and time period. They reflect certain changes in hospitalization practice in Germany.

Adult↗
PubMed1983

Is there an increase of reproductive rates in schizophrenics? III. An investigation in Nordbaden (SW Germany): results and discussion.

Two cohorts of schizophrenic patients admitted to a psychiatric hospital for the first time either during 1949-50 or 1965-67 were compared with matched controls for reproductive rates before and 13 years after onset of psychosis. Patients of both admission periods had reduced marriage rates. After onset of the disease the rate of reproduction was decreased in males of both periods, but not in females. Patients of both periods did not differ from control values with respect to marital fertility. It has repeatedly been reported that fertility of schizophrenics has been increasing in recent times. Comparison of total reproduction, rate of marriage and marital fertility in patients of the two admission periods and matched controls did not yield any evidence for increasing rates. Instead, the results favour the idea that the patients parallel at a lower level the general decline of birth rates observed in Western Germany.

Adult↗
PubMed1983

3H-imipramine binding in platelets: influence of varying proportions of intact platelets in membrane preparations on binding.

Human platelets possess high-affinity 3H-imipramine binding sites. A study in ten healthy volunteers showed that platelet preparations produced by mechanical disruption contained varying proportions of intact platelets, as measured by the cytoplasmic marker enzyme LDH. This may invalidate the protein reference. Higher proportions of membranes in the preparations lead to higher Bmax values of imipramine binding (fmol/mg protein). The use of intact platelets in imipramine binding studies is therefore preferable to membrane preparations, particularly in studies where the interindividual variation of binding parameters is of interest.

Blood Platelets↗
PubMed1983

Pharmacogenetics of alcohol's CNS effect: implications for the etiology of alcoholism.

The electroencephalogram (EEG) offers several advantages for genetics, because it combines trait and state characteristics. In a twin study it could be demonstrated that the effect of an acute ethanol dose on the CNS as assessed by the EEG is under genetic control. Among the various genetically determined variants of the EEG, the poorly synchronized alpha EEG exhibits the most pronounced response. The examination of a series of alcoholics of both sexes as well as first-degree relatives of them revealed that in females the poorly synchronized alpha EEG may be a disposing factor for alcoholism. This result supports the idea that the disposition to alcoholism is under genetic influence not only at the metabolic but also at the pharmacodynamic level.

Alcoholism↗