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Biomedical subjects

C Jacquot

Publications and source records attributed to C Jacquot.

At least 181 records · Page 10Linked to original sources
PubMed1980

[Effects of oxilofrine on the activity of the sympathetic nervous system (author's transl)].

The effects of 1-(4-hydroxyphenyl)-2-methylamin-propanol- (1) (oxilofrine, 4-HMP) on the catecholamine metabolism were investigated in vitro in isolated rat hearts and spleen sections. Investigations were conducted in vivo to determine the influence exerted by the sympathomimetic agent on the noradrenaline biosynthesis in the heart and on the oxygen-dependent enzymes tyrosine hy droxylase and dopamine-beta-hydroxylase. Oxilofrine is an excellent inhibitor of the noradrenaline storage in the heart (DI = 1.5 X 10(-6) mol/l). At the same time, the sympathomimetic agent releases noradrenaline from the storage compartments. In this process, preferably newly synthetised noradrenaline is released both from the heart and from the spleen. This double mechanism of action is associated with an acceleration of the noradrenaline biosynthesis and an increase in enzymal activity of tyrosine hydroxylase and dopamine-beta-hydroxylase. The transmitter concentrations in the region of the postsynaptic receptors are enhanced by oxilofrine.

Animals↗
PubMed1980

[Presynaptic adrenergic mechanisms of action of oxilofrin].

The presynaptic adrenergic mechanisms of action of 1-(4-hydroxyphenyl)-2-methylamino-propanol-(1) (4-HMP, oxilofrine) were investigated in the rat. The sympathicomimetic agent is stored in the heart by a mechanism with saturation characteristics, resembling noradrenaline in this respect. Inhibitors of the neuronal and extraneural binding of noradrenaline at the same time suppress the tissular uptake of 4-HMP. Investigations in vivo in the tissular distribution and on the subcellular distribution in the iris, vas deferens and spleen confirm the affinity of 4-HMP for the storage vesicles containing noradrenaline. Stimulation of the spinal nerves results in a release of the sympathicomimetic agent. This underlines the significance of the presynaptic mechanisms of action for the pharmacological properties of 4-HMP.

Animals↗
PubMed1980

[Effects of oxilofrine on the release and storage of noradrenaline in cardiac sections of the rat (author's transl)].

Experiments in vitro have shown 1-(4-hydroxyphenyl)-2-methylamino-propanol-(1) (oxilofrine, 4-HMP) to release noradrenaline from cardiac ventricular sections. This effect sets in at a concentration of 10(-5) mol/l and reaches the 30% level at 5X10(-5) mol/l. The inhibition of noradrenaline storage is still more pronounced. At 5 X 10(-5) mol/l the inhibition is 60%. The significance of both mechanisms of action of the sympathomimetic agent is discussed in comparison with compounds of related structure.

Animals↗
PubMed1980

[Traumatic rupture of the isthmic region with bowel ischemia (author's transl)].

One case of traumatic rupture of the isthmic region of the aorta is reported. Acute ischemia of the inferior limbs, anuria and paraplegia have led to the diagnosis. During the first hours after the trauma bowel ischemia appeared. The repair of the aorta was achieved within the seven hours after the accident but the bowel ischemia stayed irreversible. A such complication has not been reported in the literature as long as we know and we are think that it is possible to range this complication among some of the ischemic enterocolitis.

Aorta, Thoracic↗
PubMed1980

Renal lesions in the hypertensive syndromes of pregnancy: immunomorphological and ultrastructural studies in 114 cases.

One hundred and fourteen women presenting during pregnancy with an abnormally high blood pressure and/or proteinuria had a renal biopsy usually on the 8th day following delivery. The pathological specimens were examined by light and/or electron and/or immunofluorescence microscopy. Forty-one cases were studied with all three techniques. The patients could be allocated to six groups on the basis of clinical criteria. The first two groups (52 patients) showed the typical clinical and pathological features of classical preeclampsia. The remaining 62 women (four groups) had isolated hypertension, and, of these, 42 had a renal pathological pattern similar to that of preeclampsia. These 42 patients also had persistent hyperuricemia. Thus in pregnancy, hypertension and persistently elevated uric acid levels are indicative of glomerular lesions of "pregnancy induced nephropathy".

Adult↗
PubMed1979

The effect of various stimulated altitudes on the turnover of norepinephrine and dopamine in the central nervous system of rats.

The elimination rate constant, half-life and turnover time of dopamine (DA) and norepinephrine (NE) were determined, after inhibiting their biosynthesis by alpha-methyl-para-tyrosine (alpha MT), in the hypothalamus, striatum and the remainder of the brain of rats exposed to different degrees of hypobaric hypoxia, corresponding to altitudes of 1,800, 3,800, 5,200 and 7,000 meters. The effects varied as a function of the degree of hypoxia and the brain region studied. The turnover time of NE in the hypothalamus remained unchanged, regardless of the altitude, while in the rest of the brain the rate constant of neurotransmitter elimination decreased inversely as a linear function of the degree of hypoxia. On the contrary, the changes of the DA turnover time in the striatum and the rest of the brain, were biphasic, being accelerated by moderate altitudes (1,800 m) and retarded by the two highest simulated altitudes studied as a function of hypoxia. The differential effects of hypoxia on NE and DA turnovers are attributed to different sensitivities of the respective enzyme systems.

Altitude↗
PubMed1978

Radiobiological investigations in Cosmos 782 space flight (Biobloc SF1 experiment).

Several biological objects were flown in Cosmos 782 in order to investigate the effects of HZE cosmic particles and other environmental factors of space. Space flight results in chromosomic aberrations in lettuce seeds, decreased germination rate and increased frequency of abnormalities in tobacco seeds and decreased developmental capacity in Artemia eggs. In lettuce and tobacco seedlings, changes were observed not only in seeds hit by heavy ions but also in nonhit seeds. The results indicate that exposure to the space environment can induce important changes in biological objects and emphasize the usefulness of investigations carried out on organisms less complex than mammals.

Animals↗
PubMed1978

Long-term blood pressure changes in renal homotransplantation.

Long-term blood pressure changes were studied in 50 patients who had undergone renal homotransplantation. Excluded were those subjects with arterial stenosis of the transplanted kidney, acute or rapidly progressive rejection, or recurrent glomerulonephritis, as well as those retaining their own diseased kidney(s). The blood pressure after the end of the first year was stable and, therefore, was utilized as the reference blood pressure for this study. One year after transplantation, hypertension was observed in 20% of the patients. Mean blood pressure was positively correlated with age (P less than .01), body weight (P less than .001), and serum creatinine level (P less than .001), and negatively correlated with maintenance dose of prednisone (P less than .01). A higher incidence of hypertension was observed in cadaver kidney transplantation than in living related-donor transplantation. The study minimizes the role of glucocorticoids and emphasizes the role of renal factors in the mechanism of the long-term blood pressure changes.

Adult↗
PubMed1977

Effects of amphetamine on brain biogenic amines in isolated and aggregated rats.

d- and 1-amphetamine were injected (15 mg/kg i.p.) into isolated or aggregated rats. Both d- and 1-forms decreased the noradrenaline levels of brain areas in isolated and in aggregated rats. d-Amphetamine decreased 5-hydroxytryptamine (5-HT) and 5-hydroxyindolacetic acid (5-hiaa) levels in aggregated rats only. 1-Amphetamine induced no change in 5-HT and 5-HIAA levels. The greater sensitivity of aggregated rats to d-amphetamine can be ascribed to a change in 5-HT metabolism rather than to a modification of noradrenaline levels.

Amphetamine↗
PubMed1977

Preliminary results of the Biobloc experiment on the Cosmos 782 flight: effects of cosmic rays on brine shrimp eggs and tobacco seeds.

The aim of the Biobloc experiment is to determine the biological effects of cosmic rays. Biobloc is a stack made up of biological layers and physical detectors (nuclear emulsions and plastic). Artemia eggs and tobacco seeds are used by French workers. Irradiation by cosmic heavy ions induces a late developmental inhibition of Artemia eggs. A light increase of emergence rate is observed for the non-hit eggs. The results are compared with those of previous space experiments. Investigations on tobacco seeds are in progress.

Animals↗
PubMed1977

[The heart and lithium. Apropos of a case of lithium poisoning with intracavitary electrocardiographic exploration].

Among the secondary effects of the salts of Li+, which are widely used in psychiatric treatment, cardiac toxicity appears to be rare. The authors report the case history of a female of 24 years of age, with no previous cardiac history, who presented with Li+ intoxication and a supra-His atrio-ventricular block, followed by episodes of sinus arrest (or of sino-atrial block), accompanied by either a junctional rhythm or by periods of prolonged asystole. The results of the endocavitary electrocardiographic investigation are described. These cardiac effects are compared with the general findings reported in the literature; ECG modifications of the T wave are more common, but Li+ may cause other changes: sinus, atrial or ventricular arrhythmiás, disorders of AV conduction, and cardiomyopathies. The main modes of action which have been suggested are of interference with the other cations (K+, Na+, Ca++) in exchanges across membranes, and an effect on membrane adenyl-cyclase stimulated by catechol-amines.

Adult↗
PubMed1977

[Assessment of 81 traumatic vascular lesions of the limbs (author's transl)].

A review of 81 cases of vascular trauma of the limbs in 75 patients treated at the Grenoble University Hospital from 1967 to 1975 confirms the classical etiological, pathological and clinical findings. Analysis of the results led us to emphasise the necessity of bone and vascular repair which should be complete from the start, verified by peroperative radiological control. The application of now well-established rules to the treatment of vascular trauma should lead to a better prognosis in the case of popliteal lesions (76 p. cent of good results out of 17 revascularisations).

Adolescent↗
PubMed1977

Uptake, turnover and release of norepinephrine in pigmented and albino rat eye.

The uptake, turnover and release of norepinephrine were studied in the rat eye as a function of its pigmentation. The endogenous norepinephrine level was increased in eyes with melanic pigments and the exogenous amine uptake was decreased. In the coloured eye, two sites for norepinephrine uptake and release were present. Desipramine did not inhibit in the same manner the amine in the albino and pigmented eye. No variation was found in the norepinephrine biosynthesis for the two races of rats. The release rate of exogenous amine was higher in the pigmented rat eye.

Albinism↗