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Biomedical subjects

P Chatelain

Publications and source records attributed to P Chatelain.

288 records · Page 16Linked to original sources
PubMedDate not supplied

Insulin-like growth factor I/somatomedin C action on 2-deoxyglucose and alpha-amino isobutyrate uptake in chick embryo fibroblasts.

Maximum 125I-IGF-I/Sm-C total binding to chick embryo fibroblasts was 3% at +37 degrees C and decreased to less than 1% in presence of 2.8 X 10(-9) M unlabelled IGF-I/Sm-C. Insulin did not compete with IGF-I/Sm-C for the binding to cells. Biological action of IGF-I/Sm-C was evaluated on 2-deoxyglucose and alpha-aminoisobutyrate uptake. Results are compared with those obtained with insulin. Maximal peptide effects on the two transport processes were obtained at a 0.65 X 10(-7) M concentration and for a 120 minute association time, whereas cells were markedly less sensitive to insulin and time response curves were different. These results suggest that insulin action on nutrient uptake in chick embryo fibroblasts is not mediated by the binding of the hormone to IGF-I/Sm-C receptors.

Aminoisobutyric Acids↗
PubMedDate not supplied

[Assessment and value of the polybrene microplate test for study and identification of irregular anti-erythrocyte antibodies].

We have adapted Lalezari's manual polybrene test for use with microplate technology for screening and identification of anti-erythrocytes antibodies with a view to future automation. The technical conditions have been standardized, firstly by using a programmable centrifuge and a sequential shaking, secondly by using a preservative medium for panel after dispensing onto microplates. This methodology has been run in parallel with papain test and LIS indirect antiglobulin test: 7,000 screenings have been performed and their results are considered here. Our results are comparable to those described for automatic and manual techniques. The polybrene-microplate test affords a fast, reliable, handy and inexpensive means of screening and identification for irregular antibodies. It appears as an additional method for enzymatic tests in microplate. An antiglobulin test can be carried out after negative tests.

Antibodies↗
PubMedDate not supplied

Comparison of [3H]nitrendipine binding to heart membranes of normotensive and spontaneously hypertensive rats.

We compared the binding properties of [3H]nitrendipine in heart membranes from 9- and 24-week-old spontaneously hypertensive rats (SHR) and their normotensive controls (WKY). In native membranes of 9-week-old SHR and WKY and of 24-week-old WKY, [3H]nitrendipine binds to a single class of binding sites with high affinity (Kd, approximately equal to 0.20 nM) and high capacity (Bmax, approximately equal to 96 fmol X mg protein-1). By contrast, in membranes of 24-week-old, SHR, Kd and Bmax increased significantly to 0.30 nM and 137 fmol X mg protein-1, respectively. Addition of 1 mM Ca2+ had no effect on [3H]nitrendipine binding in WKY but decreased the Kd value to 0.18 nM in 24-week-old SHR. Bmax remained 40% above the value in WKY. Inhibition and activation of specific binding by nifedipine and dilitiazem are identical in both strains. We conclude that the differences in [3H]nitrendipine binding in hearts of aged SHR are due to a decreased Ca2+ content and might reflect a functional adaptation.

Animals↗
PubMedDate not supplied

Allosteric modulation of [3H]nitrendipine binding to cardiac and cerebral cortex membranes by amiodarone.

The possible interaction between the antianginal and antiarrhythmic drug amiodarone and the slow calcium channel was investigated by competition binding experiments in guinea-pig cerebral cortex and rat heart membranes using [3H]nitrendipine as radioligand. Amiodarone displaced specifically bound [3H]nitrendipine from cerebral cortex and cardiac membranes in an apparently competitive manner. In saturation binding experiments, apparent affinity for [3H]nitrendipine progressively decreased with increasing concentrations of amiodarone, whereas maximal binding capacity (Bmax remained unchanged. Both diltiazem and verapamil reversed the inhibitory effect of amiodarone on [3H]nitrendipine binding to cerebral cortex membranes. Together these results suggest that amiodarone exerts a pseudocompetitive inhibition on [3H]nitrendipine binding by acting at a site in allosteric interaction with the 1,4 dihydropyridine binding site associated with the calcium channel. The data are compatible with the existence of a common binding site for diltiazem, verapamil, and amiodarone. These observations are discussed in connection with the pharmacological properties of the drug.

Allosteric Regulation↗
PubMedDate not supplied

Successful management of a postinfarction left ventricular rupture using a sutureless technique with concomitant myocardial revascularization.

We present a case of left ventricular (LV) rupture that occurred on the second day after inferolateral myocardial infarction (MI). An aggressive diagnostic approach with rapid coronary angiography prior to surgical repair provides a benefit characterized postoperatively by complete recovery of myocardial contractility in the akinetic infarcted area. We believe that coronary artery disease associated with subacute ventricular rupture may, in fact, be better investigated and simultaneously treated under a protocol of early surgical repair.

Aged↗
PubMedDate not supplied

[Amyloidosis following juvenile chronic arthritis in a 3-year-old child].

A case of amyloidosis revealed by a nephrotic syndrome in a 3 years old girl with juvenile chronic arthritis is reported. The child died from this amyloidosis at the age of 4 years. The main biochemical, clinical and therapeutics aspects of this form of secondary amyloidosis (amyloidosis AA) are discussed.

Amyloidosis↗
PubMedDate not supplied

[Value of the assay of urinary gonadotropins in pediatric endocrinology].

An assay for urinary gonadotropins (UG) performed after acetone extraction is presented. This dosage was performed either on a sample of the 24 assay urine, or on the fractionated 12 hr/12 hr urines (night/day) in normal children whose ages ranged from 2 to 20 years and in children presenting with various endocrine diseases (on about 2,000 urine samples). Normal values were established according to sex and stage of puberty. In boys, the lack of overlap between values of LH (UI/24 hr) observed in stage I (prepubescent, 9-13 yrs) and those observed in stage II represents an obvious biological marker of the onset of puberty. The night/day ratio of LH also increases close to puberty, reflecting the onset of the well-known night secretion of LH, at the time of the first stages of puberty. In girls, the preferential increase in FSH is the best criterion for the onset of puberty. In children with endocrine diseases, assay for UG/24 hr is a valuable parameter of the gonadotropic function allowing 1. to separate delayed puberty from hypogonadotropic hypogonadism; 2. to confirm a diagnosis of precocious puberty and 3. to control a treatment with LHRH analogous.

Adolescent↗
PubMedDate not supplied

[Echographic diagnosis of a cachexia-inducing diencephalic tumor].

In a 2 month-old girl presenting with severe cachexia, ultrasonography of the brain through the fontanella showed a diencephalic tumor. Ultrasonographic pictures were compared with those obtained with CT scan. This report emphasizes the value of ultrasonography in such a syndrome with little neurologic symptoms.

Brain Neoplasms↗
PubMedDate not supplied

Fantofarone (SR 33557): cardiovascular actions in anesthetized dogs.

We have compared the ability of a new calcium channel-blocking agent, fantofarone (SR 33557), to modify the cardiovascular function in anesthetized dogs, with that of nifedipine. Administration of fantofarone (50 micrograms/kg, i.v.) resulted in substantial changes in cardiac function, such that stroke volume was increased by 40% (p < 0.05) and left ventricular relaxation diminished by approximately 10% (p < 0.05), while heart rate was not significantly altered. Total peripheral resistance was simultaneously reduced by 40% (p < 0.05). Higher doses of fantofarone (100 and 500 micrograms/kg, i.v.) produced further modifications of cardiovascular function without significant effect on heart rate. Administration of nifedipine also resulted in significant reductions in total peripheral resistance and diastolic arterial pressure and, at the same time, in increased cardiac output. However, an important distinction between the effects of nifedipine and fantofarone was that nifedipine increased heart rate. To differentiate between the direct and indirect effects of fantofarone, studies were performed in stellectomized anesthetized dogs. In these conditions, in contrast to nonstellectomized dogs, fantofarone (100 micrograms/kg, i.v.) lowered heart rate considerably (from 122 +/- 9 to 67 +/- 10 beats/min; p < 0.01) and the increase in stroke volume was greatly limited in comparison to nonstellectomized dogs. The cardiovascular actions of fantofarone are, therefore, significantly influenced by reflex mechanisms. Thus, these studies indicate that fantofarone is a new calcium antagonist capable of significantly modifying the cardiovascular function without increasing heart rate.

Anesthesia↗