Search PubMed⌕ Search

Biomedical subjects

R Bernard

Publications and source records attributed to R Bernard.

At least 19 recordsLinked to original sources
PubMed1992

Effects of TGF beta 1 on the proliferation and differentiation of an immortalized astrocyte cell line: relationship with extracellular matrix.

The astrocyte cell line (C.LT.T.1.1.), which is immortalized and has retained a normal density-dependent regulation of growth, is a suitable model for studying the relationships between proliferation, differentiation, and the production of extracellular matrix. The growth factor TGF beta 1 was used to modulate these processes. When added to proliferative cells, it inhibited growth and caused morphological changes. It also suppressed the growth arrest at confluence, so that the cells formed multilayers of parallel spindle-shaped cells. Whereas untreated control cells expressed progressively the glial fibrillary acidic protein (GFAP) after arrest of multiplication, the addition of TGF beta 1 to proliferative cells prevented GFAP expression and accumulation of its mRNA. Concomitantly, it increased the amounts of laminin, fibronectin, and collagens synthesized during the growth phase and greatly altered the composition and the structure of the matrix deposited at confluence. In contrast, when added after cell differentiation had begun, TGF beta 1 did not alter the appearance of the matrix whereas it still stimulated, but to a lesser extent, extracellular matrix components production. The results show that TGF beta 1 prevents the transition from the proliferating to the differentiating state and correlatively alters the composition and structure of the extracellular matrix.

Animals↗
PubMed1992

Effect of blocking angiotensin II receptor subtype on rat sympathetic nerve function.

This study examined effects of nonpeptide angiotensin II (Ang II) receptor subtype antagonists on the interaction of sympathetic function and Ang II in pithed rats. Effects of spinal cord stimulation (0.5-4 Hz) and norepinephrine (0.3-3 micrograms/kg i.v.) on mean arterial pressure (recorded with a carotid arterial catheter), cardiac output (measured with an electromagnetic flowmeter and flow probe around the thoracic ascending aorta), total peripheral resistance, and heart rate were determined. The subtype 1-selective Ang II receptor antagonist losartan (previously known as DuP 753) at 10 mg/kg i.v. blocked the hemodynamic responses to Ang II at 1 microgram/kg i.v. It inhibited mean arterial pressure and total peripheral resistance responses but not cardiac output and heart rate responses to spinal cord stimulation. In contrast, it reduced mean arterial pressure and cardiac output responses but not total peripheral resistance and heart rate responses to intravenous norepinephrine. Given at 100 mg/kg i.v., the subtype 2-selective receptor antagonist PD123177 did not reduce hemodynamic responses to intravenous Ang II, spinal cord stimulation, and intravenous norepinephrine. These results suggest that endogenous Ang II facilitates the release of norepinephrine from sympathetic nerve terminals in the vasculature of pithed rats. Similar to the Ang II receptor in vascular smooth muscle, the prejunctional Ang II receptor in pithed rats appears to be of subtype 1.

Angiotensin Receptor Antagonists↗
PubMed1992

Pyruvate dehydrogenase activity is stimulated by growth hormone (GH) in human mononuclear cells: a new tool to measure GH responsiveness in man.

Human peripheral mononuclear cells (PMC) were used to examine the effects of hGH and insulin on the activity of the pyruvate dehydrogenase (PDH) complex. Incubation of PMC with 10(-7) mol/L hGH or insulin increased basal PDH activity. Hormonal effects were maximal (50-60% above control values) at 15 min. Later on, activation progressively decreased and was no longer detectable at 30 min. Total PDH activity was unaffected by hormonal treatment. PMC were subfractionated into lymphocytes and monocytes to assess the sensitivity of each cell types to the hormones. hGH significantly increased basal PDH activity in lymphocytes and monocytes (38% and 70% above control values, respectively), whereas insulin increased basal PDH activity only in monocytes (151% above control value). PMC from healthy subjects aged 1-45 yr were incubated for 15 min with 10(-7) mol/L hGH or insulin before PDH measurement. An increase of enzyme activity higher than 20% was observed in 26 patients out of 29 with hGH, and in 15 out of 18 with insulin. In conclusion, hGH is able to stimulate PDH activity of human mononuclear cells. This hormonal effect allows rapid evaluation of the cellular responsiveness of hGH in various pathophysiologic situations.

Adolescent↗
PubMed1992

[Value of serum immunoglobulin assays in early myocardial infarction].

Serum immunoglobulin (Ig) levels were assayed in 672 patients admitted for acute myocardial infarction with onset within 24 hours of hospitalization. Supranormal Ig levels (A > or = 300, G > or = 1,200) or subnormal Ig levels (M < 40 mg/100 ml) were seen in patients with one or several risk factors (diabetes mellitus, alcohol abuse) or a history of previous myocardial infarction. Patients with one or more Ig anomalies were more likely to exhibit unfavorable outcomes, including early death, suggesting that increased viscosity due to aggregation of Ig molecules may occur.

Acute Disease↗
PubMed1992

Influence of upright exercise on pulmonary hemodynamics in left heart failure.

Studies in severe chronic stable heart failure (HF) indicate that pulmonary resistance might remain unchanged during exercise and could subsequently contribute to limitation in exercise capacity of these patients. We assessed the possible role of the exercise decreases in mixed venous oxygen tension on this phenomenon in fifteen patients with chronic congestive heart failure (N.Y.H.A. functional classes II to IV) who underwent a symptom-limited treadmill exercise test with hemodynamic monitoring as well as repeated arterial and mixed venous blood gas analysis. For all patients there was an increase in cardiac output (from 3.7 +/- 0.2 to 6.7 +/- 0.5 l/min, p less than 0.001) and pulmonary wedge pressure (from 16 +/- 2 to 31 +/- 3 mm Hg, p less than 0.001) along with exercise with highly significant decrease in total systemic resistance and no significant (from 25.6 +/- 1.5 to 15.8 +/- 1.0 U, p less than 0.001) changes in pulmonary vascular resistances. Arterial blood oxygen tension increased from 86 +/- 3 to 99 +/- 3 mm Hg (p less than 0.001) and mixed venous oxygen tension (PvO2) decreased from 33 +/- 1 to 22 +/- 1 mm Hg (p less than 0.001). Changes in pulmonary vascular resistance during exercise were inversely related to changes in PvO2 (r = -0.61; p less than 0.05). We conclude that the observed decrease in PvO2 might be a determinant of unchanged pulmonary vascular resistance during treadmill-exercise test in severe heart failure patients.

Adult↗
PubMed1979

Acute myocardial infarction: coronary care unit, hospital ward or home management?

The need of admission of all patients with acute myocardial infarction in a CCU is questioned by some british authors. A critical review of their publications stresses the most important methodological problems they could not overcome; consequently they cannot allow any valuable comparison. There are no randomized trial related to the comparison of general ward to CCU care, but the available data obtained by studies based on bed availability show a definite advantage of the CCU. At the present stage of our knowledge, admission in a CCU must be recommended to all patients seen in the first hours after the presumed onset of the disease; after some delay (12 h?) systematic admission is not justified any more and the decision should be taken according to each case, in relation to the clinical status and familial or social conditions.

Acute Disease↗
PubMed1978

Computerized tomography in the study of West's syndrome.

37 children presenting with West's syndrome were studied by computerized tomography scanning. An abnormality consisting of diffuse cerebral atrophy, predominating in the fronto-temporal region, was demonstrated in 30 cases. The abnormality was sometimes associated with calcification (tuberous sclerosis) or malformation (agenesis of the corpus callosum). The aetiology of the atrophy and its relationship to clinical and electroencephalographic signs is discussed. Computerized tomography scanning is recommended for children with West's syndrome in order to distinguish between primary and secondary cases, and for greater prognostic accuracy.

Adolescent↗
PubMed1978

[Evaluation of one year experience with cerebral tomodensitometry in pediatric neurology].

Cerebral tomography allows the delineation of areas modified by edema or necrosis, the visualization of calcifications undetectable by standard x-ray examination, extra- or intra-cerebral blood effusions and neoformations of the cerebrum or of its envelopes. It also reveals slight or localized cerebral atrophies that other neuro-radiologic techniques sometimes failed to detect. It appears therefore worthwhile to reconsider pediatric neurology according to this new type of investigation. Its sole difficulty in young children, is the requirement of a half hour immobility, best obtained by general anesthesia. However, the rapid improvements of this technique will probably permit to overcome this slight drawback.

Brain Diseases↗