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Biomedical subjects

A Robertson

Publications and source records attributed to A Robertson.

At least 253 records · Page 14Linked to original sources
PubMed1979

Self-stimulation of the nucleus accumbens and ventral tegmental area of Tsai attenuated by microinjections of spiroperidol into the nucleus accumbens.

The contribution of dopaminergic neurons to self-stimulation of the ventral tegmental area, nucleus accumbens and prefrontal cortex was investigated. The ventral tegmental area is the site of non-striatal dopaminergic neurons and their axons project to the nucleus accumbens and prefrontal cortex. Injections of spiroperidol, a dopamine antagonist, into the nucleus accumbens significantly reduced self-stimulation of the ipsilateral ventral tegmental area but did not influence self-stimulation of the contralateral ventral tegmental area. Injections of spiroperidol into the prefrontal cortex did not reduce self-stimulation of the ipsilateral or contralateral ventral tegmental area. Electrical stimulation of sites in the nucleus accumbens positive for self-stimulation antidromically activated neurons of the ventral tegmental area, and a reduction of discharge of these neurons following administration of apomorphine suggested that they were dopaminergic neurons. These observations provide additional evidence implicating dopaminergic neurons in brain-stimulation reward and suggest that dopaminergic neurons contribute to self-stimulation of the nucleus accumbens but not the prefrontal cortex.

Animals↗
PubMed1979

Facilitation of self-stimulation of the prefrontal cortex in rats following chronic administration of spiroperidol or amphetamine.

The effect of chronic administration of spiroperidol, a dopaminergic antagonist, on self-stimulation of the prefrontal cortex was investigated. When spiroperidol was administered either before or after daily self-stimulation tests for 9 days, self-stimulation rates were significantly elevated for several weeks following withdrawal of the drug. Self-stimulation of the nucleus accumbens, supracallosal bundle, and other forebrain sites was not altered, suggesting that the increased self-stimulation of the prefrontal cortex was not due to increased motor activity. Self-stimulation of the prefrontal cortex was also facilitated by chronic administration of d-amphetamine whereas self-stimulation of the supracallosal bundle was suppressed and self stimulation of the nucleus accumbens was unchanged. The results suggest that dopamine modulates self-stimulation of the prefrontal cortex. Additionally, the effects of chronic spiroperidol on self-stimulation of this structure may model the therapeutic effects of neuroleptics in humans.

Amphetamine↗
PubMed1979

Responses of the early chick embryo to external cAMP sources.

Early chick embryos were stimulated with local sources of cAMP. Three major effects were observed: bending of the embryonic axis, attraction of cells on the ventral surface of the embryo, and disruption of the blastodisc. Each had a characteristic concentration dependence. These results are compared with those from studies of cells disaggregated from similar embryos.

Animals↗
PubMed1979

Waves propagated during vertebrate development: observations and comments.

The status and possible roles of propagated waves occurring during vertebrate embryogenesis are discussed. Some preliminary data for waves observed in time-lapse films of early chick (Gallus domesticus) and Medaka (Oryzias latipes, a teleost) are given. The general similarities between these phenomena and wave propagation during cellular slime mold aggregation are pointed out and it is suggested that the control of development by propagated waves in regulative embryos is not only widespread but also depends on a common cellular mechanism.

Animals↗
PubMed1978

Cyclic adenosine monophosphate production by embryonic chick cells.

Cells dissociated from 1-day-old chick embryos produce a pulse of cyclic adenosine monophosphate (cyclic AMP) when stimulated with cyclic AMP. There is a stimulus threshold concentration of about 10(-8) molar cyclic AMP and an upper limit, above which the response is suppressed, of about 6 X 10(-6) molar. The response occurs within 5 seconds of stimulation and corresponds to an average pulse size in the range of 10(7) molecules per cell.

Animals↗
PubMed1978

Treatment of advanced Hodgkin's disease with B-CAVE following MOPP failure.

Between March 1973, and December 1976, 22 patients who developed disease progression during or after MOPP therapy were treated with a new combination, B-CAVe (Bleomycin 5 mg/m2 iv days 1, 28, 35; CCNU 100 mg/m2 po day 1; adriamycin 60 mg/m2 iv day 1; and vinblastine 5 mg/m2 iv day 1). Objective responses were achieved in 17 of 22 patients (77%) and 11 of 22 responses were complete (50%). The actuarial survival for all patients is 16.4 months. For complete responders the median is 24 months with 2 complete responders dead without evidence of Hodgkin's Disease. Median relapse free survival for complete responders has not been reached at 35+ months while that for partial responders is 14 months. Significant adriamycin cardiotoxicity was encountered in two patients. There were no life threatening bacterial infections during B-CAVe. Two patients died of Pneumocystis carinii several months after cessation of therapy. B-CAVe is effective in the therapy of advanced Hodgkin's disease after MOPP failure, and this regimen is comparable to other previously reported MOPP salvage combinations.

Adolescent↗
PubMed1977

The incidence of gonorrhoea in urban Rhodesian Black women.

The incidence of gonorrhoea in urban Black women seen in an antenatal clinic, a gynaecological clinic and a family planning clinic, was studied. Swabs taken from the urethra, endocervix and rectum were cultured by means of the Clinicult system. The overall incidence of gonorrhoea was 9.7%. In the antenatal clinic the incidence was 2%, in the gynaecological clinic it was 11% and in the family planning clinic it was 12%.

Black or African American↗