Search PubMed⌕ Search

Biomedical subjects

S Dumas

Publications and source records attributed to S Dumas.

47 records · Page 3Linked to original sources
PubMed1987

Modulation of tyrosine hydroxylase gene expression in the central nervous system visualized by in situ hybridization.

A rat tyrosine hydroxylase [TyrOHase; tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] cDNA probe was used for in situ hybridization studies on histological sections through the locus coeruleus, substantia nigra, and the ventral tegmental area of the rat brain. Experimental conditions were established that yielded no background and no signal when pBR322 was used as a control probe. Using the tyrosine hydroxylase probe, we ascertained the specificity of the labeling over catecholaminergic cells by denervation experiments and comparison of the hybridization pattern with that of immunoreactivity. The use of 35S-labeled probe enabled the hybridization signal to be resolved at the cellular level. A single injection of reserpine into the rat led to an increase of the intensity of the autoradiographic signal over the locus coeruleus area, confirming an RNA gel blot analysis. The potential of in situ hybridization to analyze patterns of modulation of gene activity as a result of nervous activity is discussed.

Animals↗
PubMed1987

Predicting hospital readmission of elderly cardiac patients.

Sixty hospitalized elderly cardiac patients were tested using the Geriatric Functional Rating Scale (GFRS) and were followed four months postdischarge. Significant relationships were found between GFRS scores and readmission status. These data substantiate the potential usefulness of GFRS as a predictive instrument to identify those high-risk hospitalized elderly cardiac patients who need social-health services in the posthospital recovery period.

Aged↗
PubMed1982

Abducens paresis. A rare presenting sign of posterior-inferior cerebellar artery aneurysm.

Posterior fossa aneurysms comprise a minority of intracranial aneurysms, but produce a wide array of signs and symptoms. We report a patient with slowly progressive unilateral sixth nerve paresis secondary to a saccular aneurysm of the posterior-inferior cerebellar artery. Neuroradiologic investigation of subarachnoid hemorrhage is discussed, and the literature concerning posterior circulation aneurysms is reviewed.

Abducens Nerve↗
PubMed1978

Effect of estrogen on sensitivity of rabbit bladder and urethra to phenylephrine.

The sensitivity of alpha-adrenoceptors to phenylephrine as indicated by the ED50 of the rabbit bladder and urethra was compared for segments in vitro from control (estrous), ovariectomized, ovariectomized-estrogen-treated, and pregnant animals. In control animals there was a trend for urethral segments to be more sensitive to phenylephrine (lower ED50) than bladder segments. This difference was abolished by castration, which decreased the sensitivity of the anular urethral segment, and by pregnancy, which tended to enhance the sensitivity of the bladder. The tension generated by bladder segments was enhanced by pregnancy and tended to be decreased by castration. The effects of castration tended to be reversed by treatment with estrogen (1 microgram per kg of body weight per day for 14 days). These data indicate that estrogen can influence the response of the urethra and urinary bladder to alpha adrenergic stimulation.

Animals↗
PubMedDate not supplied

Co-expression of tyrosine hydroxylase messenger RNA 1 and 2 in human ventral mesencephalon revealed by digoxigenin- and biotin-labelled oligodeoxyribonucleotides.

In situ hybridization experiments, using oligodeoxyribonucleotides specific for the two major expressed human tyrosine hydroxylase mRNAs, were performed on human brain sections at the level of the mesencephalon. The specificity of the probes was ascertained by Northern blot experiments carried out with independently in vitro synthesized human tyrosine hydroxylase mRNAs. For in situ hybridization experiments, oligodeoxyribonucleotides were labelled with nucleotides tagged with digoxigenin or biotin molecules. The hybridized oligonucleotides were detected by antibodies coupled with peroxidase and alkaline phosphatase enzymes, which yield, with appropriate substrates, brown and purple products, respectively. The simultaneous detection of the two mRNAs with digoxigeninated and biotinylated probes revealed that these two mRNAs are co-expressed in single cells. The purple product obtained with alkaline phosphatase exhibits a discrete distribution within the dopaminergic cells suggesting these mRNAs are associated with sub-cellular structures. Finally, a heterogeneity in the intensity of the labelling of reactive cells with both probes was visualized as well as the expression of the two mRNA species in neurites.

Aged↗
PubMedDate not supplied

[In situ hybridization on tissue section: a new method for studying the amacrine cells of the retina and the centers of the visual system].

In situ hybridization of nucleic acid probes, encoding the key enzymes of the synthesis of neurotransmitters, with sections of retina is a new method giving complementary informations to the data obtained by immunocytochemistry and autoradiography. It will allow a better characterization of amacrin cells, whatever might be their type, and a refined understanding of their function. It is an accurate tool to investigate the mechanisms of retinal degenerations and spontaneous or experimental microphtalmia.

Animals↗