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Biomedical subjects

D Rousseau

Publications and source records attributed to D Rousseau.

15 recordsLinked to original sources
PubMed1992

Induction of H1(0)-gene expression in B16 murine melanoma cells.

Histone H1(0) accumulation is associated with the terminal stage of differentiation. Unlike other H1 histones, it is able to accumulate in the absence of DNA synthesis, however the transcription of its gene is cell-cycle dependent. The regulation of H1(0)-gene expression has been studied during the induced differentiation of B16 cells and during reversion of the process, which may be achieved when induced cells are released into an inducing-agent-free medium. During the earlier period of induced differentiation, H1(0) mRNA showed over-expression when the cells were still proliferating. Then the amount of H1(0) mRNA decreased as the cells became arrested in G0-G1. H1(0) mRNA half-life measurements and run-on experiments demonstrated that such modulation of the amount of mRNA originated from a transcriptional control of H1(0)-gene expression. When induced cells reverted to a proliferative undifferentiated state, H1(0) mRNA decreased very rapidly, indicating that an active process was involved in this decay. This behavior differed from that observed in rat liver hepatocytes allowed to proliferate and de-differentiate after partial hepatectomy, or in murine erythroleukemia cells when the inducing agent was removed from the culture.

Animals↗
PubMed1991

Regulation of histone H1(0) accumulation during induced differentiation of murine erythroleukemia cells.

Histone H1(0) is one of the potential candidates that may contribute to the onset and stabilization of a genetic program during induced differentiation of murine erythroleukemia cells. In an attempt to understand better the role of H1(0) in this process we have tried to determine at which level the regulation of its induced accumulation occurs. Protein H1(0) was found to increase by a factor of 3 while its mRNA increased by a factor of 14, due to activation of gene transcription. As shown by H1(0) half-life measurements, the difference between the actual amount of H1(0) and that expected from the amount of mRNA was not due to increased turnover of the protein. Fractionation of the translational apparatus at several times during induction, revealed that H1(0) mRNA was efficiently transferred to the high molecular weight polysomes. The rate of synthesis of H1(0) was also increased by a factor of 4. Taken together, these results suggest the existence of a strong control at the translational level, which regulates H1(0) accumulation.

Animals↗
PubMed1989

Behavioural and histological effects of low concentrations of intraventricular AF64A.

The effects of ethylcholine mustard aziridinium ion (AF64A; 0.3, 1.0 and 3.0 nmol), injected into each lateral ventricle in the rat, were determined in a range of behavioural tests, each involving a learning component. Effects were observed at 1.0 and 3.0 nmol/side and, to a lesser extent, at 0.3 nmol/side. Habituation of locomotor activity was impaired and deficits in learning were obtained using a variety of mazes including the Morris swimming maze. Slight, non-significant impairments occurred in shock reinforced behaviours. Histologically, marginal effects were observed at 0.3 nmol/side, and slight ventricular dilatation with necrosis of the hippocampus, restricted to the site of injection at 1.0 nmol/side; at 3.0 nmol/side more widespread necrosis was apparent. Biochemical efficacy of the lesions in terms of cholinergic changes was confirmed by analysis of acetylcholinesterase (AChE) levels showing decreases in the hippocampus and the cortex; no studies were carried out with respect to other neurotransmitters. Cognitive deficits can therefore be obtained by i.c.v. injection of AF64A at doses which cause significant cholinergic changes with minimal histological disturbances.

Animals↗
PubMed1987

Delivery volumes of the 1- and 3-mm pins of a Cathra replicator.

This study was undertaken to determine the volumes delivered by the 1- and 3-mm pins of a Cathra replicator and to evaluate reproducibility. The weight of broth transferred by these pins served to assess the delivery volume. Repeated transfers with the 1- and 3-mm pins showed, on average, a delivery of 0.1 and 2 microliters, respectively.

Bacteriological Techniques↗
PubMed1985

Colpohistologic correlations. A computerized study.

Data from 300 colposcopic cases were computerized to study the correlations between the colposcopic observations and the histologic and other data. Colposcopy was shown to be most useful in women under 35 years of age. Use of oral contraceptives (the Pill) seemed to relate to a higher level of successful colposcopic visualization and may even prevent the need for conization, based on a higher incidence of negative endocervical curettages. Although 14.5% of the cases were colposcopically undergraded and 17% overgraded when compared to the histopathology, the histologic predictability of the colposcopic observation of white epithelium and vascular changes (punctation and mosaicism) was excellent. Colposcopy remains an essential technique in the appraisal and management of cervical intraepithelial neoplasia.

Adult↗
PubMed1979

[Enzymatic study of muscle fibers of the antero-lateral wall of the abdomen in man: functional interpretation].

After a recall of muscular histo-enzymology, the authors expose the results of an analysis of the antero-lateral muscles of the abdomen. They establish a predominance of the muscular fibers, type I, that are tonic as compared with the muscular fibers, type II, that are phasic. Thus the role of support and of maintenance of the intra-peritoneal pressure by these muscles is confirmed. The tonic characteristic is also important for the functional reeducation and the electrotherapy of the abdominal wall.

Abdominal Muscles↗
PubMedDate not supplied

[Neonatal primary hyperparathyroidism caused by clear cell hyperplasia].

Neonatal primary hyperparathyroidism is rare but must be evoke during respiratory distress with thoracic deformity and hypercalcemia. The plasma immunoreactive parathyroid hormone level allows the diagnostic. This case, with diffuse hyperplasia of water-clear cells type, develops rickets of vitamin D deficiency before surgery. A large parathyroidectomy (7/8) was performed and the child is normo-calcemic 2 years after. The time of surgery is function of calcium level.

Female↗