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Biomedical subjects

B Rossignol

Publications and source records attributed to B Rossignol.

At least 91 records · Page 5Linked to original sources
PubMed1978

Lanthanum as a tool to study the role of phosphatidylinositol in the calcium transport in rat parotid glands upon cholinergic stimulation.

We describe the effects of lanthanum on protein secretion, potassium efflux, calcium uptake and phosphatidylinositol turnover stimulated by cholinergic agonists in rat parotid glands. Carbachol increases in vitro calcium uptake, protein secretion and K+ efflux through muscarinic receptor; however it fails to stimulate protein discharge or K+ release in a incubation medium free of calcium. Lanthanum inhibits calcium uptake, protein secretion and K+ efflux induced by carbachol without impairing protein discharge stimulated by norepinephrine through the beta-adrenergic receptor. Norepinephrine, in the presence of calcium in the incubation medium, stimulates the K+ efflux through the alpha-adrenergic receptor: this effect is suppressed by lanthanum. These results emphasize the role of increased influx of calcium in the cellular phenomena controlled by muscarinic or alpha-adrenergic receptors. Carbachol increases phosphatidylinositol turnover in the absence of calcium in extracellular medium; indeed it is shown that carbachol increases the rate of phosphatidylinositol breakdown and that lanthanum impairs this cholinergic effects. From these data it is suggested that the interaction between cholinergic agonist and muscarinic receptor could induce a stimulation of 'phosphatidylinositol turnover' which could control the calcium influx according to the gradient through the plasmalemma membrane.

Animals↗
PubMed1977

[Carcinoid heart disease secondary to a tumor of the small intestine. Apropos of a case with associated tricuspid and pulmonary insufficiency].

The authors report a case of carcinoid heart disease secondary to a tumour of the small bowel with liver metastases. There were severe lesions of the endocardium on the right side of the heart, with gross pulmonary and tricuspid incompetence. The left side of the heart did not escape but the fibrous plaques were limited to the papillary muscle of the mitral valve, and had no effect upon the haemodynamics. The pathogenesis of the strange cardiac lesion may be partly explained in terms of the toxicity to the endothelium of bradykinin. In spite of the serious nature of the valvular damage is it right to consider surgical correction, bearing in mind the fact that the prognosis of carcinoid syndrome is still very poor despite treatment?

Aged↗
PubMed1977

[Dromotropic effects of drug combinations. Initial results bearing on a combination of deslanoside and ajmaline].

The electrophysiological effects of the cardiotropic drugs have been studied in man by the agency of endocavitary electrocardiography. The effects of drug combinations, which are often prescribed therapeutically, have been studied less often. The authors report the results of a preliminary study of the combination of deslanoside with ajmaline in 26 patients; its effects were compared with those using each drug separately. This combination seems to have true dromotropic effects; although deslanoside alone, in the doses used, does not modify conduction below the bundle of His, it can still act synergistically with ajmaline at this level. A detailed study of the pharmacological effects as a function of the original status of conduction shows that at the level above the bundle His, the dromotropic action is quantitively less on healthy conducting tissue than on abnormal tissue. The effects of ajmaline on the conduction times below the bundle seem to be similar whether or not there is any conduction defect under basal conditions. The difficulties in obtaining and interpreting such measurements in man are discussed in the hope of arriving at a general protocol for studying drug combinations.

Adult↗
PubMed1977

[Diagnosis of posterior infarction. Value of vectorcardiography. Apropos of 108 cases, 31 of which had exclusively posterior necrosis].

An analysis of the vectorcardiogram results (VCG) in 77 cases with a posterior extension of an infarct and 31 cases with an exclusively posterior infarction (EPI) has allowed us to distinguish some diagnostic criteria relative to the extension, or localisation, of an infarct in the posterior segment. The maximum anterior vector (MAV) appears late (36.5 ms +/- 5), and the amplitude of its projection onto Z is increased; the maximum vector (V max) appears early (41.5 ms +/- 4.5), and its orientation is anterior (+ 24 degrees +/- 11); the interval separating MAV from V max is reduced to 5 ms; the transition from before backwards is late (50 ms +/- 6); the ratio of anterior surface to posterior surface is increased (1.45); there is a terminal delay, most frequently occuring in the right posterior quadrant in 78 percent of cases; and finally, the T loop approaches the Z axis. Repeat electrocardiograms in patients with EPI show the most frequent changes to be represented (in 25 cases out of 31) by the following formula: AQRS " 0 degrees, R/S greater than or equal to 1 in V2, RV2 greater than RV6. The diagnosis of an exclusively posterior infarction can therefore be made with a high degree of certainty when these electrocardiographic abnormalities are associated with the clinical picture of coronary insufficiency.

Computers↗
PubMed1976

Effect of carbachol on 45Ca uptake and protein secretion in rat lacrimal gland.

Carbachol stimulates 45Ca uptake and protein secretion in rat lacrimal glands. At low concentration (10-8 M) atropine inhibits these effects but phentolamine and propranolol (10-5 M) are ineffective. The optimum response in both processes is obtained at the same concentration (10-6 M) of the cholinergic agonist. Vinblastine (10-4 M) reduces protein discharge induced by carbachol without modifying the uptake of 45Ca stimulated by the parasympathetic mediator. Calcium influx is proposed as the primary effect of cholinergic inducers in secretory processes.

Animals↗
PubMed1976

[Association of progressive external ophthalmoplegia and myocardiopathy with complete atrioventricular block. Apropos of a new case].

The authors report the case of a 31 year old man with an occulomotor palsy, who was admitted to hospital with complete atrio-ventricular block and syncopal attacks. The possible pathogenic significance of this association has given rise to differing hypotheses. A review of the literature shows that the occulomotor palsy has been interpreted either as an ophtalmoplegia (of neurogenic origin) because of the associated neurological findings and the histological changes in the occulomotor nuclei, or as an occular myopathy because of the associated muscular disorders and the changes on electromyography and on histology. The relationships between the occulomotor palsy and the cardiac condition are also discussed.

Adult↗
PubMed1975

Regulation of protein secretion and metabolism in rat salivary glands. Effects of norepinephrine and carbachol on the glycogenolysis in submaxillary glands.

Carbachol and norepinephrine induce glycogen breakdown in rat submaxillary glands incubated in vitro. These effects are suppressed by specific inhibitors of cholinergic receptors (atropine, a muscarinic blocker) and of adrenergic receptors (propranolol, a beta-blocker and phentolamine, an alpha-blocker). The beta-adrenergic effect seems to be mediated through the adenosine 3':5'-monophosphate system, whereas the alpha-adrenergic and cholinergic effects are dependent of Ca2+ influx into cell. In the two latter systems, it is suggested that a direct activation of phosphorylase b kinase by calcium takes place. These data clearly indicate that glycogenolysis in rat submaxillary glands in vitro can be independently affected by sympathetic and parasympathetic agents via specific receptors.

Animals↗