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Biomedical subjects

M Vincent

Publications and source records attributed to M Vincent.

At least 325 records · Page 18Linked to original sources
PubMed1983

[Cobalt and sintered metal carbides. Value of the determination of cobalt as a tracer of exposure to hard metals].

Cobalt urinary excretion should be a good way to know the level of exposition of subjects submitted to hard metals. The study is done on 28 workers of 3 different workrooms. Sunday 24 hours diuresis is retained. For 5 workers, the urinary cobalt measurements are done from samples made at the beginning and the end of work during 5 days. Atmospheric dust measurements are realized in different points of the 3 workrooms (individual and general samples). For measures atomic absorption spectrometry is used. The results show a good correlation between cobalt exposure and urinary concentrations. Friday evening urinary cobalt is a good expression of week exposure. The results obtained well correlate with those of others authors. Cobalt urinary measures are proposed for supervision of workers exposed to hard metals.

Air↗
PubMed1982

A new technique for the measurement of urinary 6-keto-prostaglandin F1 alpha: normal values in adults.

A new sensitive and specific radioimmunoassay for measurement of urinary 6-keto-prostaglandin F1 alpha is described. In this technique, 6-keto-prostaglandin F1 alpha was first extracted and separated from prostaglandins F2 alpha, F1 alpha, E2, E1, A2 and A1 by using an original high performance liquid chromatographic method with an overall recovery of 74.4 +/- 0.9%. The radioimmunoassay used a highly specific antibody raised in the rabbit. The sensitivity of the method was 1.8 pg. Between-assay reproducibility was at 7.7%. As previously reported for prostaglandins E and F alpha, the urinary excretion of 6-keto-prostaglandin F1 alpha, measured in 28 healthy adult subjects, was found to be significantly (p less than 0.001) higher in men (319 +/- 21 ng/24 h) than in women (190 +/- 14 ng/24 h). The chromatographic separation method described here could also be applied to the radioimmunoassay of other primary prostaglandins.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

[4 cases of Mycoplasma pneumoniae pneumonia].

The authors report four cases of Mycoplasma pneumoniae pneumonia which occurred towards the end of 1981, concurrently with an intensification of this infection. Three patients had severe respiratory distress and one required ventilatory assistance. The features shown on chest roentgenograms are discussed. All four patients had been treated initially with penicillin or cephalosporin. This report is evidence that patients with pneumonia should be given a macrolid as the first treatment.

Adult↗
PubMed1982

Dynamic structure of bovine adrenal cortex microsomal membranes studied by time-resolved fluorescence anisotropy of all-trans-1,6-diphenyl-1,3,5-hexatriene.

The motional properties of all-trans-1,6-diphenyl-1,3,5-hexatriene embedded in the microsomal membranes and in extracted lipid liposomes from bovine adrenal cortex are studied by fluorescence anisotropy decay measurements. The results demonstrate the existence of a nonvanishing value of the anisotropy (r infinity) in both systems. The r infinity values are significantly higher in the total membranes than in the protein-depleted liposomes, following the trend of the steady state anisotropy values previously reported (Gallay, J., Vincent, M., de Paillerets, C., Rogard, M., and Alfsen, A. (1981) J. Biol. Chem. 256, 1235-1241). This indicates that the depolarizing rotations of the probe are more restricted in the presence of proteins. No detectable effect of proteins on the reorientational correlation time can be observed. The temperature dependence of r infinity is not similar in both systems. In the complete membranes, a sharp decrease of r infinity value takes place between 27 and 32 degrees C, corresponding to 1/3 of the total curve of r infinity versus temperature is translated to lower temperatures. Thermal dependence of the reorientational correlation time is essentially the same in lipids and in complete membranes with an activation energy of 5 kcal mol-1. The results suggest that proteins play an essential role in organizing the deepest lipid region in the microsomal membranes from bovine adrenal cortex.

Adrenal Cortex↗
PubMed1982

[Effects of propranolol and indomethacin upon urinary hydroxyproline in hyperthyroid patients (author's transl)].

Hydroxyproline excretion was increased by hyperthyroid patients. This increase was related to thyroid hormone levels. Propranolol administration induced a decrease in hydroxyproline excretion and in immunoreactive triiodothyronine. Indometacin administration induced a decrease in urinary excretion of prostaglandins but had no effect on hydroxyproline excretion. These data suggest that the increased bone resorption of hyperthyroidism may involve a catecholamine beta receptor-dependent mechanism and is probably independent of prostaglandins.

Adult↗
PubMed1982

Nanosecond fluorescence anisotropy decays of n-(9-anthroyloxy) fatty acids in dipalmitoylphosphatidylcholine vesicles with regard to isotropic solvents.

A set of n-(9-anthroyloxy) fatty acids [2-, 7-, 9-, and 12-(9-anthroyloxy)stearic acid (AS) and 16-(9-anthroyloxy)palmitic acid (16-AP)] has been studied by time-resolved and steady-state fluorescence anisotropy measurements in isotropic media (i.e., propylene glycol and a liquid paraffinic oil, Primol 342) and in vesicles of dipalmitoylphosphatidylcholine. The two modes of rotation, "in-plane" and "out-of-plane", of the anthroyl ring can be detected by varying the excitation wavelength. In both isotropic solvents, the value of the in-plane rotational rate is of the same order of magnitude as the out-of-plane rate for each one of the n-(9-anthroyloxy) fatty acids. In propylene glycol, the anthroyl ring motions are similar for all derivatives except for the 16-AP for which the fluorophore rotates at a higher rate. In the liquid paraffinic oil, identical motions of the fluorophore are observed for the 7-, 9-, and 12-AS; the motion for the 16-AP is again faster, while that for the 2-AS is slower. Moreover, the fluorophore motion for each probe is faster in this solvent that in propylene glycol in conditions of identical viscosity. When embedded in phospholipid bilayers, these probes report the microenvironment at a graded series of depths from the surface to the center of the bilayer [Haigh, E. A., Thulborn, K. R., & Sawyer, W. H. (1979) Biochemistry 18, 3525--3532]. Studies in dipalmitoylphosphatidylcholine vesicles have been performed at three temperatures (21, 37, and 47 degrees C) corresponding to different lipid phases. The out-of-plane mode of rotation is unhindered as demonstrated by an anisotropy decay profile asymptotic to zero. Thus, evaluation of a membrane "fluidity" parameter at different depths of the bilayer is possible, even in the steady-state mode of observation. When the in-plane mode of rotation contributes to the anisotropy decay, a hindrance to the motion is observed below the gel to liquid-crystalline transition. Then information about lipid order can be obtained from the plateau value (r infinity) of the fluorescence anisotropy decay. In the pretransition temperature range (37 degrees C), the results evidence the existence of structural lipid changes mainly localized in the hydrophobic core of the bilayer. The main transition leads to a complete disappearance of the hindrances on the in-plane rotation.

Anthracenes↗
PubMed1982

Selective reduction of adrenaline turnover in the dorsal midline area of the caudal medulla oblongata and increase of hypothalamic adrenaline levels in the Lyon strain of genetically hypertensive rats.

Catecholamine levels and turnover have been studied in 5 week old male genetically hypertensive (LH) and normotensive (LN) rats of the Sprague-Dawley Lyon strain. The results demonstrate increased hypothalamic adrenaline levels and a reduced adrenaline turnover in the dorsal midline of the medulla oblongata (DCMO) in the LH rats compared with LN control rats. The reduction of adrenaline turnover in the DCMO may contribute to the development of spontaneous hypertension.

Animals↗
PubMed1982

Intracellular translocation of cellular and heat shock induced proteins upon heat shock in Drosophila Kc cells.

The intracellular distribution of cellular and heat shock induced proteins (hsp) was studied during a heat shock to Drosophila Kc cells. The different hsp's are unequally distributed between the intracellular organelles; while hsp 84 shows an exclusive cytoplasmic location, hsp 70 is equally distributed between the nucleus and the cytoplasm. The low molecular weight (MW) hsp's 22--26 are mainly concentrated in the nuclear fraction. Hsp 34 also shows a preferential nuclear localization but differs from the 22-26 hsp group with regard to its solubility in salt. During the heat shock (HS) treatment, a major preexisting microsomal polypeptide of relative mass (Mr) 45 000 with some properties similar to cytoskeletal proteins is translocated to the nuclear pellet. This translocation does not occur during arsenite treatment which also induces the synthesis of some hsp's. Furthermore, the hsp's synthesized in response to this arsenite treatment do not become associated with the nucleus as during the HS. Consequently the nuclear translocation of the 45 000 Mr protein does not seem to be involved in the induction of the high MW group of hsp's. Furthermore, it suggests that the hsp's which are found in the nuclear pellet upon HS do not have a nuclear localization per se. It rather reflects a temperature-dependent translocation of certain cellular proteins and hsp to the nucleus during a HS.

Animals↗
PubMed1982

Evoked trigeminal nerve potential in chronic trichloroethylene intoxication.

Results of a study of trigeminal nerve impairment resulting from trichloroethylene intoxication by the somatosensory-evoked potential method reveal three kinds of abnormalities: increased stimulation voltage, excessive latency delay with morphological abnormalities, and excessive graph amplitude. These abnormalities confirm clinical disturbance (hypesthesia of the trigeminal nerve area) and open debate about the real mechanism of trichloroethylene neurotoxicity. Industrial intoxication by solvents, particularly trichloroethylene, is common. We have conducted a study of 188 workers chronically exposed to trichloroethylene and have confirmed the selective neurological disturbances of this intoxication in the trigeminal nerve (20%) [3, 10]. We utilized a new experimental method, developed for studies of chronic intoxications effecting the median nerve [5, 8], of recording the somatosensory evoked potential following stimulation of the trigeminal nerve [4, 6, 7]. The workers in this study were selected following clinical evaluation of their facial sensitivity and trigeminal nerve reflexes. In this paper we present our preliminary results on 11 workers, 9 suffering effects of intoxication and 2 controls.

Environmental Exposure↗
PubMed1982

[Vascular reactivity in young genetically hypertensive rats of the Lyons strain].

The vascular sensitivity to noradrenaline (NA), phenylephrine (PE) and angiotensin II (AII) has been studied in 8 week-old male rats of the genetically hypertensive (LH) and normotensive (LN) Lyon strains. Vascular sensitivity was obtained from the blood pressure response-curves observed in urethane anesthetized rats having received ganglioplegics and atropine. A cocaine pretreatment allowed to assess the influence of a reuptake blockade on the responses to NA. The vascular sensitivity of NA, PE and AII was normal in LH rats, while the cocaine blocked reuptake process was less important in LH than in LN rats. When comparing these results to those, previously obtained on the activity of the sympathetic nervous system, it appeared that: in the young prehypertensive LH rat an increased sympathetic activity was associated with a normal vascular reactivity to NA. On the contrary, in old LH rats, with established hypertension, the sympathetic activity returned to normal while a vascular hypersensitivity to NA developed. Therefore it is concluded that the overall efficacy of the sympathetic nervous system is increased at all stages of the development of genetic hypertension in the Lyon strain.

Angiotensin II↗
PubMed1982

[The renin-angiotensin system and the sympathetic nervous system in essential hypertension].

In 112 patients with essential hypertension (HTA), free of any therapeutic and receiving the standard ward, a significant inverse relationship was found between age and plasma renin activity (PRA) and plasma aldosterone (PA), measured in the supine and upright position. Urinary epinephrine and norepinephrine were not related with age. When dividing the patients in 4 different age groups, it appeared that those younger than 30 years exhibited a significantly higher PRA and PA values and a higher frequency of borderline hypertension (45 p. 100) than the older ones (12 p. 100). So as to determine the characteristics associated with borderline HTA, it was necessary to eliminate the influence of age. This was achieved by comparing two groups of carefully age-matched patients, one with borderline HTA and the other with stable HTA. The only significant difference found was a significantly more marked increase in PRA in response to orthostatism, in patients with borderline HTA. Since renin responses to an orthostatic stress are largely mediated by renal nerves, this result suggest that borderline HTA could be associated with an increased reactivity of the sympathetic nervous system.

Adult↗