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Biomedical subjects

D McDonald

Publications and source records attributed to D McDonald.

At least 145 records · Page 8Linked to original sources
PubMed1979

Mesolimbic dopaminergic neurones and somatodendritic mechanisms.

The concept that a neurone may release transmitter from both dendritic and axonal sites was investigated by studying mesolimbic dopaminergic neurones. The rat ventral tegmentum (containing dendrites and somata of mesolimbic dopaminergic neurones) possessed high levels of dopamine and tyrosine hydroxylase. Slices of ventral tegmentum accumulated [3H]dopamine (15 or 60 nM) and stimulus-induced release of [3H]dopamine was observed after elevated potassium (44 mM). The potassium-induced release was calcium-dependent. These dopaminergic parameters were compared to those found for nucleus accumbens (containing terminals of mesolimbic dopaminergics neurones). Thioridazine and clozapine elevated 3,4-dihydroxyphenylacetic acid (DOPAC) concentration in ventral tegmentum.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

Dental anaesthesia.

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Anesthesia, Dental↗
PubMed1976

Steroid metabolism by human mammary carcinoma.

The ability of human mammary tumors to convert 7alpha 3H-testerone to estrogens was examined in order to determine whether this bore any relationship to estrogen receptor and steroid sulfurylation levels; such levels being indicative of hormone dependency. In 8 out of 9 tumors, formation of estradiol-17beta from testosterone was demonstrated. Those tumors showing the lowest conversion of testosterone to estradiol-17beta possessed the highest levels of dehydroepiandrosterone sulfotransferase which lends support to data implicating sulfurylation in the regulation of steroid metabolism in human tumors. All tumors activated sulfate to adenosine-3'-phospho-5'-phosphosulfate and the concentrations were significantly correlated withe the recorded levels of dehydroepiandrosterone sulfate. Estrogen receptor levels did not show any obvious relationship to the other parameters.

Breast Neoplasms↗
PubMedDate not supplied

Molecular analysis in the diagnosis of pediatric lymphomas.

Thirty-five pediatric lymphomas were categorized as either Burkitt's lymphoma (BL), lymphoblastic lymphoma (LL), or large cell anaplastic lymphoma (LCAL) by histological and immunophenotypic methods. They were further characterized by molecular analysis of their antigen receptor genes. Southern blot (SB) and polymerase chain reaction (PCR) techniques were compared in the detection of immunogloblin heavy chain gene (IgH) rearrangement. T cell receptor beta (TCR beta) rearrangements were analyzed by SB and TCR gamma gene rearrangements by PCR. The PCR method of IgH and TCR gamma gene analysis was preferred to the SB methods, because there were fewer equivocal results in IgH gene analysis, TCR gamma rearrangement was more frequently detected than TCR beta in both lymphoblastic and large cell anaplastic lymphomas, and the PCR technique was more rapid, required less DNA, and could be used with archival material. In addition, analysis of IgH gene rearrangement by PCR was more specific for assessing B cell lineage. Although most of the molecular data were easily interpreted, occasional ambiguous results were seen due to genetic events other than antigen receptor gene rearrangement affecting the genetic analysis. Thus, it is imperative to interpret these genetic data in the context of adequate morphological and immunophenotypic analysis.

Blotting, Southern↗