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Biomedical subjects

B Lesser

Publications and source records attributed to B Lesser.

14 recordsLinked to original sources
PubMed1991

Laterality in schizophrenia. A reaction time study.

A laterality study in schizophrenia was carried out by measuring reaction time (RT) in a baseline condition and while subjects were engaged in a concurrent task. In the baseline condition, a clinical measure of psychoticism was associated with differential slowing with the right hand in schizophrenic dextrals but not in a control group of affective dextrals. The concurrent task suppressed the effect of psychoticism on RT performance. The results suggest that left-hemisphere deficits in schizophrenia are state dependent, and so not necessarily due to cortical dysfunction.

Adult↗
PubMed1991

Negative symptoms and reaction time in schizophrenia.

This study explored the association of negative symptoms and reaction time. Negative symptoms were specifically associated with reaction time slowing and variability in schizophrenics, but not in affective disorders. The finding of specificity did not extend to other measures of the deficit syndrome nor to motor performance. An abbreviated version of the negative symptom scale was especially effective in separating groups.

Adult↗
PubMed1990

Voluntary motor performance in psychotic disorders: a replication study.

Voluntary motor performance was used to investigate the hypothesis of a continuum of psychosis from depression through schizophrenia. 43 schizophrenic, 36 schizoaffective, 50 major depressive, 20 manic, and 25 nonpsychotic patient controls were tested for tapping speed, finger dexterity, hand grip strength, and neuropsychological motor performance. Sex was included as an independent variable, and the effects of psychotropic drugs were evaluated. A continuum of motor dysfunction from depression through schizophrenia was not obtained. A measure of current psychotic symptoms was not associated with motor or neuropsychological performance. Motor performance was significantly worse in schizophrenic, schizoaffective, and psychotic affective disorders, when compared to nonpsychotic affective disorders. In this final analysis, psychoticism was defined by history. The results are discussed in terms of the hypothesis that psychoticism is a trait that is independent of diagnosis.

Humans↗
PubMed1989

Reaction time impairment in schizophrenia and affective illness: the role of attention.

A young but chronic group of schizophrenic and affective disorders patients was tested for simple reaction time (RT) and RT while engaged in a concurrent task. The affective disorders patients were subdivided by the presence of psychotic features. The results show that extreme slowing of RT is due to psychoticism and is not characteristic of nonpsychotic affective illness. Extreme intrasubject variability, however, was specific to schizophrenia, and may be a trait marker of the disorder.

Adult↗
PubMed1976

Control of proliferative growth in androgen responsive organs and neoplasms.

Growth of a normal androgen-responsive organ appears to be ordered by the function of three constraint mechanisms which are sensitive to the intranuclear concentration of androgens. For the complete expression of these constraint mechanisms, several properties underlying hormonal responsiveness must be manifest by the cell, including the presence of cytoplasmic receptor, the ability to transfer androgens into the nucleus, the competence to form nuclear receptor, and the fidelity of the interaction between androgens and chromatin. Cytoplasmic receptor alone is not an exclusive indication of hormonal dependence in vivo, but its presence is associated with enhanced ability of the cell to incoropate androgens into the nucleus. Androgens are required for the initiation of DNA synthesis and cell proliferation, and nuclear receptor may not be required for these responses. On the other hand, it is possible that the function of the latter molecule is concerned with negative feedback or cellular autolysis.

Androgens↗
PubMed1974

Effect of duration of the period after castration on the response of the rat ventral prostate to androgens.

If 5alpha-dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one) is administered to castrated rats before prostatic atrophy has commenced, secretory activity of the prostate is stimulated, but not proliferation. Once the number of cells has fallen below normal, hormone induces proliferation until the normal cellular complement has been restored; then proliferation ceases, but secretory activity is stimulated.

Androgens↗
PubMed1974

The effects of 5alpha-dihydrotestosterone on the kinetics of cell proliferation in rat prostate.

The regenerating rat prostate was used as an experimental model to determine the effects of 5alpha-dihydrotestosterone on certain parameters of cell proliferation, including the duration of the phases of the cell cycle and the size of the cellular growth fraction. Rats castrated 7 days previously were treated with daily subcutaneous injections of 5alpha-dihydrotestosterone for 14 days; 48h after the beginning of therapy, cells in the process of DNA synthesis were labelled with a single injection of radioactive thymidine and the progress of these cells through the division cycle was observed. Cell-cycle analysis was performed by fractionating prostatic nuclei according to their position in the cell cycle by using the technique of velocity sedimentation under unit gravity. The results indicate that during regeneration the cell population undergoes 1.8 doublings with a doubling time of 40h, and that the process involves almost four rounds of cell division with a cell-generation time of 20h. The growth fraction at any time is about 0.5, and about half the daughter cells produced do not re-enter the proliferative cycle. All cells present at the start of regeneration eventually undergo at least one division during the course of regeneration, although any given cell can divide from one to four times.

Animals↗