Search PubMed⌕ Search

Biomedical subjects

C Dreux

Publications and source records attributed to C Dreux.

At least 73 records · Page 4Linked to original sources
PubMed1983

The diffuse neuroendocrine (APUD) system.

The bulk of experimental evidence indicates that the APUD series of cells is a distinct system based upon common pathophysiological features. The diffuse nature of this system with elements in the central and peripheral nervous system suggests a more complex interaction of the body's homeostasis than has been established. It is probable that as radioimmunological and radioenzymatic assays become more widely available and standardized, other apudomas will be described. Finally, an understanding of the APUD concept, with its peculiar pluripotential for the production of biogenic amines and peptides, the multicentric nature of the disease and the possibility of multiple cell involvement, is of key importance in managing patients. Studies of the apudomas will also advance the understanding of the normal physiologic interrelationships of the APUD cells.

APUD Cells↗
PubMed1982

Melatonin synthesis by rabbit platelets.

Platelets of reserpinized rabbits, incubated in buffer containing tritiated 5-hydroxytryptamine (3H-5HT), have the ability to convert 3H-5HT into labeled compound(s) extractable with alkaline-chloroform. The bulk of the chloroform-extractable radioactivity showed a Rf value similar to authentic melatonin on silicagel thin-layer chromatography. The labelled product eluted with ethanol from the silicagel area where melatonin was suspected to reside was identified as melatonin by mass spectrometry and radioimmunoassay. Our in vitro experiments demonstrate that rabbit platelets are capable of converting 5-HT into melatonin apparently because they possess the enzymatic equipment necessary for this biosynthesis i.e. serotonin N-acetyltransferase and hydroxyindole-O-methyltransferase.

Animals↗
PubMed1982

'Pseudohypertriglyceridemia' caused by hyperglycerolemia due to congenital enzyme deficiency.

A 76-year-old man was found to have a false hypertriglyceridemia due to a 40-fold increased glycerolemia. This metabolic change was due to a deficiency in glycerol kinase (ATP:glycerol phosphotransferase, EC 2.7.1.30) activity in the cells of this patient as shown by incubation of his white blood cells with [14 C]glycerol. Several chromatographic analyses and quantitative assays were performed on plasma and urine of this patient and of his relatives. The small number of this family's members did not allow to specify the mode of transmission of this genetic trait.

Aged↗
PubMed1982

Platelet serotonin uptake and migraine.

Platelet serotonin uptake characteristics (Km, Vmax, y) were determined in platelet-rich plasma for 11 common migraineurs and 15 health volunteers. All three parameters were decreased only for the three patients having a migraine attack during blood collection, Migrainous platelets isolated on dextran or resuspended in control plasma exhibited normal serotonin uptake. This finding suggests that plasmatic factor(s) may be responsible for the decrease of platelet serotonin uptake observed during migraine attacks.

Blood Platelets↗
PubMed1982

Percutaneous absorption of 5 alpha-dihydrotestosterone in man. I. Plasma androgen and gonadotrophin levels in normal adult men after percutaneous administration of 5 alpha-dihydrotestosterone.

The distribution of 5 alpha-dihydrotestosterone to the blood following application of a solution of this androgen to the skin in a hydro-alcoholic gel was studied in order to evaluate the adequacy of the percutaneous route in correcting androgen deficiencies. In 14 adult men, daily percutaneous administration of 5 alpha-dihydrotestosterone (125 mg in 5 g gel) increases, on the average, 4 to 5 times its initial concentration in plasma. On the 14th day of treatment, repeated evaluations of plasma 5 alpha-dihydrotestosterone, between 2 and 21 h after final administration of gel, demonstrated the stability of diurnal 5 alpha-dihydrotestosterone levels and showed the regular distribution of the steroid from a presumably cutaneous reservoir. Plasma 5 alpha-androstane-3 alpha,17 beta-diol levels evolve parallel to those of 5 alpha-dihydrotestosterone. Plasma testosterone and luteinizing hormone, on the contrary, decrease considerably. No variation of follicle-stimulating-hormone is observed during treatment. The percutaneous absorption represents an interesting method for administration of a natural androgen in men, particularly because one avoids the deleterious effects of supra-physiological levels in the liver achieved with oral administration.

Adult↗
PubMed1982

Physiological and pathological variations in saliva cortisol.

A radioimmunological method for measuring saliva cortisol was worked out. It includes one extraction and one radiocompetitive reaction with an anticortisol 3-CMO:BSA immunoserum. Frequent values for saliva cortisol were determined in various physiological and pathological conditions and compared to plasma cortisol values. In adult men, the mean concentrations at 8 a.m. and midnight were respectively 14.50 +/- 7.10 and 1.40 +/- 1.21 nmol/l (mean +/- SD). In untreated women, plasma and saliva cortisol levels were not significantly different from those measured in women taking estroprogestative drugs or in pregnant women. Following stimulation by synthetic beta 1-24 ACTH (Synacthen), the saliva cortisol determined 90 min after the 8 a.m. sampling rose by over 500% whereas plasma cortisol only rose by 120%. Similarly the drop in 8 a.m. cortisol, which followed midnight administration of 1 mg of dexamethasone was larger for saliva than for plasma cortisol. In patients with adrenal hyperactivity the circadian rhythm disappeared from saliva cortisol and patients with deficient adrenal activity displayed drastically reduced levels for saliva cortisol. Saliva cortisol seems thus to be more helpful to diagnosis than plasma cortisol.

Adolescent↗
PubMed1982

Post-menopausal concentrations of plasma oestradiol, oestrone, FSH and LH and of total urinary oestradiol and oestrone after a single sublingual dose of oestradiol-17 beta.

We report the effects of sublingual absorption of a single dose (0.5 mg) of oestradiol-17 beta (E2) in 8 post-menopausal women, on plasma E2 and oestrone (E1), urine elimination of total E2 + E1 and on plasma FSH and LH. The results show that sublingual absorption of E2 occurs and that plasma concentrations of E2 obtained (between 133.2 to 320 pmol/l) in this way were higher than those obtained after percutaneous absorption of a single dose (3 mg) of E2. The ratio E1/E2 in plasma is close to that of pre-menopausal women.

Absorption↗
PubMed1982

[Xanthelasma palpebrarum and dyslipoproteinaemia: two retrospective studies (author's transl)].

In a retrospective study about 600 hyperlipoproteinaemic patients (390 men and 210 women, mean age 47), xanthelasma palpebrarum was infrequent (25 cases or 4.16 p. 100), since it was only at the third rank of chronic extra-vascular lipid deposits after arcus corneus and tendineous xanthomas. It was twice as frequent in men (5.12 p. 100) as in women (2.38 p. 100) and of regularly increasing occurrence until the sixth decade. Among the atherosclerotic risk factors, only obesity was significantly associated. The existence of atherosclerotic diseases was observed more frequently in patients with xanthelasma palpebrarum (40 p. 100) than in total hyperlipoproteinaemic population (28 p. 100). In a second retrospective study concerning 29 patients (15 men and 14 women, mean age 50), selected from the only presence of one or several xanthelasma palpebrarum, a lipoproteinaemic abnormality was observed in 27 cases (93 p. 100): 23 patients (71 p. 100) were hyperlipoproteinaemic (type IIa, IIb or IV) and in 4 out of 6 normolipidemic patients we observed an abnormal lipoprotein cholesterol distribution (LDL + VLDL cholesterol increase and HDL cholesterol decrease). In this group, we observed in nine patients (31 p. 100) unknown atherosclerotic diseases and tendineous xanthomas in other nine patients (31 p. 100).

Adolescent↗
PubMed1981

Determination of 5-hydroxyindoleacetic acid in urine by high-performance liquid chromatography: a fully automated method.

High-performance liquid anion-exchange chromatography is combined with continuous flow spectrofluorometry at an optimized pH for the determination of 5-hydroxyindoleacetic acid (5-HIAA) in urine. Its chief advantages are speed (7 min per determination), enabling measurement of large series of samples, precision (coefficient of variation = 0.72%), sensitivity (detection limit: 1 pmol) and specificity (no interference with 5-HIAA precursors or with the drugs tested). Reference values (n = 112) are 25 +/- 25 mumol per 24 h. Comparison with a reference spectrofluorometric technique shows a correlation coefficient of 0.96.

Automation↗
PubMed1980

A simple radioimmunoassay of acebutolol in plasma.

Antisera against acebutolol were produced in rabbits immunized by means of this drug conjugated with bovine serum albumin. These antisera were used to develop a method of radioimmunoassay for acebutolol. The plasma radioimmunoassay, described here, requires no extraction and is very easy to perform besides being quick, specific and sensitive. As little as 2.97 X 10(-9) mol/l of acebutolol can be detected. This radioimmunoassay is suitable for assaying the large number of samples usually measured in pharmacological studies.

Acebutolol↗
PubMed1980

Modifications of biochemical parameters in blood platelets of schizophrenic and depressive patients.

The blood platelet may be considered as an interesting model of the serotoninergic neuron in biology and pharmacology. We studied some platelet parameters in neuropsychiatric patients (depressive and schizophrenic ones): serotonin (5-HT) uptake was abnormal for all schizophrenics and lowered for depressive patients; uptake of mepacrine, a marker of 5-HT passive diffusion, was diminished for manic patients; MAO and glutathione peroxidase activities were modified, essentially for paranoid schizophrenics and some alterations of the platelet hydroxyindole level were noticed; during treatment with neuroleptics of antidepressants biological parameters led to 'normality'. These results are discussed with clinical data and a hypothesis is proposed to join the biological modifications of paranoid schizophrenics.

Blood Platelets↗
PubMed1980

Simultaneous radioimmunoassay of androstenedione, dehydroepiandrosterone and 11-beta-hydroxyandrostenedione in plasma.

A simultaneous radioimmunoassay for delta 4-androstenedione (delta 4), dehydroepiandrosterone (DHA) and 11 beta-hydroxyandrostenedione (11 beta OH delta 4) in plasma is described. This involved preparing first an anti-11 beta-hydroxyandrostenedione-3-0-carboxymethyl oxime/BSA antiserum which binds both delta 4 and 11 beta OH delta 4, and an anti-dehydrosterone-7-0-carboxymethyl oxime/BSA antiserum. A chromatographic step using celite minicolumns separates these three steroids. The method was applied to the measurement of the plasma basal values of these three androgens in control subjects. Mean concentrations (ng/ml) of delta 4, DHA and 11 beta OH delta 4 were respecstively 1.35, 6.63 and 3.13 in males; 1.35, 6.65 and 2.59 in premenopausal females; 0.46, 1.53 and 1.38 in post-menopausal females, and 0.39, 0.73 and 1.78 in children 1--6 years of age. Dynamic tests were also carried out: ACTH stimulation was found to increase delta 4, DHA and 11 beta OH delta 4. Dexamethasone had a reverse effect causing a 50% diminution in delta 4 levels, a marked decrease in DHA levels, and a 90% decrease in 11 beta OH delta 4 levels. Metyrapone test was found to produce a 223% increase in delta 4 levels, a 196% increase in DHA levels, and a decrease of more than 90% in the 11 beta OH delta 4 levels. Estroprogestative drug treatment was accompanied by a decrease of not only delta 4, but also of DHA and 11 beta OH delta 4. Preliminary clinical results concerning these steroids show a parallel increase or decrease of delta 4 and 11 beta OH delta 4 in adrenal pathology. In ovarian hyperandrogeny, delta 4 is increased and 11 beta OH delta 4 is unchanged.

Adrenocorticotropic Hormone↗
PubMed1980

Adrenocortical 11 beta-hydroxylation defect in adult women with postmenarchial onset of symptoms.

Four cases in adults of a deficiency in the 11 beta-hydroxylation of corticosteroids were investigated by both basal and dynamic biological studies. Symptoms varied from patient to patient; hirsutism, menstrual disturbance, acne, deepening of the voice, and arterial hypertension appeared post puberty. Basal testing demonstrated elevated levels of plasma androgens. These include delta 4-androstenedione (patients, 3.80-6.43 ng/ml; normal, 1.33 +/- 0.33 ng/ml), urinary 17-ketosteroids (patients, 11.8-16.7 mg/24 h; normal, 5-10 mg/24 h), and urinary dehydroepiandrosterone. The basal tests were often insufficient to show the accumulation of the precursors (especially 17-hydroxyprogesterone) which are often given as evidence for an increase in ACTH stimulation. In studying the levels of the mineralocorticoids, there was shown to be an increased basal level of tetrahydrodeoxycorticosterone (patients, 142-317 microgram/24 h; normal, 60-80 microgram/24 h) which was raised by ACTH stimulation. These results, therefore, confirm the characteristic partial enzyme defect and give evidence for the heterogeneity of this syndrome. Based on the above observations, we believe it is appropriate to rename this condition adult adrenocortical 11 beta-hydroxylation defect rather than late-onset congenital adrenal hyperplasia.

17-Ketosteroids↗
PubMed1980

[Determination of the high density lipoprotein (HDL) cholesterol in blood serum. Comparison of 3 methods: ultracentrifugation and precipitations (author's transl)].

Three methods of assaying the high density lipoprotein cholesterol were applied simultaneously to a hundred of human sera: ultracentrifugation, precipitation by concavalin A and phosphotungstic acid. The obtained results were compared by statistical means: it was shown that the three procedures were equivalent. Some of their analytical features are discussed.

Chemical Precipitation↗