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Biomedical subjects

S Matthysse

Publications and source records attributed to S Matthysse.

At least 55 records · Page 3Linked to original sources
PubMed1982

Neurochemical and genetic bases of psychopathology: future directions.

It is widely recognized that biological psychiatry must deal with the problem of resolving heterogeneous syndromes into homogeneous subtypes. In order to gain insight into this process, we studied the history of research on cerebellar ataxia, a group of neurological disorders which originally presented a problem of heterogeneity very similar to that found in psychiatry. In the ataxias, effective classification required neuropathological examination in addition to observation of symptoms, clinical course, and pattern of inheritance. Nevertheless, in the ataxias, neuropathological work still left overlap and uncertainty. Modern biochemical and genetic progress on the ataxias would have been much more difficult, however, had this preliminary neuropathological classification not been worked out. Analogies are drawn to contemporary research in psychiatry.

Cerebellar Ataxia↗
PubMed1980

Estimating age-of-onset distributions for disorders with variable onset.

A necessary item of information in many genetic analysis of complex disorders with late onset is the cumulative probability of onset by a given age. The effect of sample design upon the estimation of age-of-onset probability distribution parameters is discussed. Mathematical descriptions of several common sample designs used to estimate the distribution parameters are developed here. Failure to describe the sample space adequately can lead to erroneous genetic analyses because the cumulative probability of onset is incorrectly estimated. In genetic counseling, the errors would usually result in an underestimate of the true risk.

Age Factors↗
PubMed1979

Color blindness not closely linked to bipolar illness. Report of a new pedigree series.

A new pedigree series of bipolar manic-depressive patients admitted to the National Institute of Mental Health intramural research program was evaluated for linkage between bipolar illness and red-green color blindness, since previous studies had indicated that close linkage was generally present. Using family study methods, six informative pedigrees were investigated. Analysis was performed using a multigenerational procedure and taking into account variable penetrance. Close linkage could be definitively ruled out as a general finding. Bipolar and related illnesses are thus not generally transmitted by a single major gene close to the protan/deutan region of the human X-chromosome.

Bipolar Disorder↗
PubMed1979

Continuous variation caused by genes with graduated effects.

The classical polygenic theory of inheritance postulates a large number of genes with small, and essentially similar, effects. We propose instead a model with genes of gradually decreasing effects. The resulting phenotypic distribution is not normal; if the gene effects are geometrically decreasing, it can be triangular. The joint distribution of parent and offspring genic value is calculated. The most readily testable difference between the two models is that, in the decreasing-effect model, the variance of the offspring distribution from given parents depends on the parents' genic values. The more the parents deviate from the mean, the smaller the variance of the offspring should be. In the equal-effect model the offspring variance is independent of the parents' genic values.

Genes↗
PubMed1978

Thiethylperazine; clinical antipsychotic efficacy and correlation with potency in predictive systems.

A one-to-one relationship between clinical antipsychotic potency and pharmacologic dopaminergic antagonism is implicit in the dopamine hypothesis of neuroleptic action. Thiethylperazine maleate, a classical antiemetic phenothiazine, displays dopaminergic antagonism in behavioral, neurochemical, and neuroendocrine systems, but is paradoxical insofar as it is thought not to possess clinical neuroleptic activity. In three tests of dopaminergic antagonism--elevation of levels of CSF homovanillic acid in monkeys, striatal dihydroxyphenylacetic acid in rats, and prolactin in man--as well as in a clinical trial of neuroleptic efficacy in schizophrenics, thiethylperazine was fully active and approximately three times as potent as chlorpromazine. Differences in efficacy between this and earlier clinical studies can be accounted for on the basis of dosage.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1978

Genetic transmission of schizophrenia.

There is convincing evidence form consanguinity, twin, and especially adoption studies that schizophrenia has a genetic component. There is also evidence from studies of MZ twins for an environmental component. It is not known whether the relevant environmental factors are prenatal or postnatal, psychosocial or physical; the presence of schizophrenia in the rearing family does not seem to be etiologically significant. It is likely that schizophrenia, especially if defined by symptoms alone, is etiologically heterogeneous. Study of pedigrees with several affected individuals is a useful approach to resolving this heterogeneity. The relevant genes may not code directly for schizophrenia, but for risk factors that predispose to the illness under particular environmental conditions. Careful methodology is needed to distinguish cause from effect of studying psychosocial factors. Genetic counseling is possible on the basis of empirical risk figures, but clarification of biological risk factors and environmental preciptants will make possible a much more rational approach to counseling and prevention.

Adoption↗