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Biomedical subjects

C Dreux

Publications and source records attributed to C Dreux.

At least 55 records · Page 3Linked to original sources
PubMed1987

Plasma lipids in juvenile chronic granulocytic leukaemia.

Plasma lipid parameters (triglycerides, total cholesterol and high density lipoprotein cholesterol) were measured in 7 children with juvenile chronic granulocytic leukaemia, of whom 3 were with and 4 without xanthomas. In all cases, whatever the stage of the disease, these parameters were extremely altered. Plasma triglycerides were generally increased, total and HDL cholesterols were very low. No relationship seems to exist between these values and the occurrence of xanthomas.

Child↗
PubMed1987

[3H]protein secretion in rat parotid gland: substance P-beta-adrenergic synergism.

In parotid fragment [3H]protein, secretion induced by substance P was moderate, but strongly Ca dependent. However, secretion induced by isoproterenol was large and Ca independent. Potentiation of protein secretion was observed when substance P (SP) and isoproterenol (ISO) acted together. Addition of 10(-8) M SP caused a shift to the left in the secretion dose-response curve caused by ISO, but did not enhance ISO-induced maximal response. The potentiating effect seems to be a postreceptor event, since it can be mimicked by forskolin (FK), known to induce directly cAMP accumulation, thus bypassing the beta-adrenergic receptor. The synergism described above was, therefore, investigated at the second messenger production level. Stimulation of parotid gland fragments by simultaneous addition of SP plus ISO or FK did not modify cAMP nor inositol trisphosphate (IP3) accumulation induced independently by each secretagogue alone. The ionophore A23187 was also able to potentiate secretion induced by a beta-adrenergic agonist, this effect being totally abolished by external calcium omission, thus suggesting a role for external calcium in this potentiation phenomenon. These results suggest that the potentiation phenomenon observed is a postreceptor event that occurs at a step distal from the second messenger production.

Animals↗
PubMed1987

Simple laboratory test of neuroendocrine disturbance in depression: 11 p.m. saliva cortisol.

Saliva cortisol was measured at 11 p.m. in a sample of 74 psychiatric inpatients composed of 24 primary endogenous depressives, 40 secondary depressives and 20 nondepressives (DSM III and Saint-Louis criteria). Primary depressives had significantly higher 11 p.m. saliva cortisol levels than nondepressives (p less than 0.02) and secondary depressives (p less than 0.05). In contrast, there were no significant differences between secondary depressive and nondepressive saliva cortisol levels. A saliva cortisol cutoff limit of 3.45 nmol/l identified primary depressives with a sensitivity of 62.5% and with a specificity of 75% in the depressive group, and 90% in the nondepressive group. The measurement of saliva cortisol at 11 p.m. could be used alone as a reliable and practical index of hypothalamic-pituitary-adrenal axis activity in depression, especially in outpatients.

Adolescent↗
PubMed1987

[Blood phenolsulfotransferase and monoamine oxidase-B activity in essential arterial hypertension].

Circulating phenolsulfotransferase M and P and monoamine oxidase activities were determined in 18 untreated essential hypertensive patients and in 35 normotensive healthy controls. Phenolsulfotransferase M is involved in the sulfoconjugation of catecholamines and their metabolites while PST P preferentially sulfates phenolic substrates. After lysis of whole blood, enzymatic activities were determined by radioenzymatic techniques using as substrates 3-methoxy-4-phenoxyphenylglycol for PST M, phenol for PST P and [14C] beta-phenylethylamine for MAO. Blood MAO activity measured by this method is fully accounted for by platelet MAO-B activity. Concerning blood PST activities, no significant difference was found in hypertensive patients compared to normotensive controls (PST M: 1.69 +/- 0.17 versus 1.66 +/- 0.08 nmoles of MHPG-sulfate/ml of blood/hour; PST P: 0.36 +/- 0.05 versus 0.27 +/- 0.04 nmoles of phenol-sulfate/ml of blood/hour). MAO activity was higher in women than in men. Significantly lower MAO B activities were observed in hypertensive patients both in men (19.25 +/- 2.20, n = 8 versus 24.35 +/- 2.22, n = 14, desaminated beta-phenyl-ethylamine/10(9) platelets/hour, x +/- SEM, p less than 0.05) and in women (23.92 +/- 2.74, n = 10 versus 35.76 +/- 2.35, n = 21, p less than 0.01) when compared to normotensive controls of the same sex. Recent in vitro studies have suggested that a reduction in platelet MAO B activity may be induced by an alteration in the phospholipidic and/or calcium environment of the enzyme. Low MAO activity in other tissues such as liver or vascular endothelium could contribute to the high sympathetic tone observed in these patients.

Arylsulfotransferase↗
PubMed1986

Biochemical and pharmacological characterization of histamine-mediated up-regulation of human platelet serotonin uptake. Evidence for a subclass of histamine H2 receptors (H2h) highly sensitive to H2 receptor antagonists.

The stimulatory effect of histamine: H (1.2 to 3-fold increase) on serotonin (5-HT) uptake by human platelets was observed after a 5 min incubation period in the presence of 2.5 X 10(-7) M histamine, followed by subsequent 5 min incubation of the platelets with 10(-7) M [3H] 5-HT. Methyl, ethyl and acetyl substituents in the side chain of H mimicked the stimulatory effect of H. In contrast, H analogs methylated at the position N-1 of the imidazole ring of H, as well as imidazole and histidine inhibited platelet 5-HT uptake. The cAMP-inducing agents forskolin and theophylline have no effect on 5-HT uptake when they are tested alone or in combinations with H. In contrast, the cGMP-inducing agent sodium nitroprusside (10(-7) M-10(-6) M) stimulated and potentiated H-mediated up-regulation of 5-HT uptake. Histamine H2 receptor agonists and antagonists are more potent than drugs acting on H1 receptors (H2 greater than H1). However, the inhibition constants Ki are not consistent with those determined for typical H1, H2, H3 receptors characterized in other tissues. This findings provide further evidence for the existence of multiple forms of H receptors and suggest the involvement of a subpopulation of H2 receptors, highly sensitive to H2 receptor antagonists (H2h), mediating 5-HT uptake in human platelets.

Blood Platelets↗
PubMed1986

Forskolin, a tool for rat parotid secretion studies: 45Ca efflux is not related to cAMP.

In the present work, we investigated, by use of forskolin, whether adenosine 3',5'-cyclic monophosphate (cAMP) level and Ca movements were modulated sequentially or in parallel by the activation of the beta-adrenergic receptor in the rat parotid gland. Forskolin-induced [3H]protein secretion was dependent on external Ca, whereas isoproterenol-induced secretion was not. This effect was not due to a requirement of adenylate cyclase for Ca, since the cAMP level increase induced by forskolin was not Ca dependent. Furthermore isoproterenol induced 45Ca efflux, whereas forskolin did not. 45Ca efflux was correlated neither to cAMP nor to secretion, since when there was a massive augmentation of cAMP there was no change in 45Ca efflux, and forskolin, which induced much secretion, was unable to induce Ca efflux. Carbachol potentiated the secretion induced by forskolin in the absence of Ca, whereas it did not potentiate the isoproterenol-induced response. From these results we suggest that beta-adrenergic receptor activation would lead to two parallel events, cAMP accumulation and Ca movements, which together would lead to maximal secretion.

Animals↗
PubMed1986

Serum inorganic sulphate: quantitation by a new radiochemical method.

A new procedure for serum inorganic sulphate determination is described. The method is simple, accurate and highly reproducible. It is based on radioisotopic dilution of 35S-sulphate by protein-free, phosphate-free serum. The decrease in initial 35S-sulphate specific activity (corresponding to added serum sulphate) is determined in the supernatant after partial precipitation of sulphate by barium ion. Serum sulphate is computed thereafter from a standard curve. Recovery of added sulphate from dialysed or undialysed serum was 100%. The intra- and interassay coefficients of variation were 3.5% and 4.1%, respectively. The serum sulphate concentration measured by this method in 93 normal subjects was 400 +/- 90 mumol/l (mean +/- SD), which agreed with the values reported in the literature. Serum sulphate did not correlate with sex (p greater than 0.40, n = 93), but a significant correlation with age was observed (r = 0.25, p less than 0.02, n = 93).

Adolescent↗
PubMed1985

[Common migraine. Changes in conjugated and unconjugated catecholamines].

Plasma levels of conjugated and unconjugated catecholamines were measured in 27 migraineurs between attacks, in 9 migraineurs 1 to 2 hours after the onset of an attack, and in 30 controls. There were no significant changes in conjugated catecholamines; in contrast, a significant rise (p less than 0.01; KS test) in unconjugated dopamine, noradrenaline and adrenaline levels was observed during attacks. These results confirm that migrainous attacks are associated with platelet activation and with overactivity of the sympathetic system.

Adolescent↗
PubMed1985

Simultaneous determination of histamine and N alpha-methylhistamine in biological samples by an improved enzymatic single isotope assay.

A modified highly sensitive and specific radioenzymatic assay for the simultaneous determination of histamine (HA) and N alpha-methylhistamine (N alpha-MH) in tissues and body fluids is described. In the presence of the enzyme histamine-N-methyltransferase and of the methyl donor [3H]-S-adenosylmethionine, the transmethylation process was about seven times more effective for HA than for N alpha-MH. In the same conditions only very low amounts of N alpha, N alpha-dimethylhistamine (N alpha, N alpha-DMH) were converted into its 1-methylated derivative. The high degree of specificity attained by this method is due to the rapid quantitative extraction of the biological fluids, to the partially purified enzyme preparation and to the thin-layer chromatography system used which allows an excellent separation of the 3H-1-methyl products of HA, N alpha-MH and N alpha, N alpha-DMH. This method is highly sensitive for the assay of HA and N alpha-MH (detection limit 10 and 50 picograms, respectively), but due to lack in sensitivity, it cannot be extended to the measurement of N alpha, N alpha-DMH. The HA content of 20-30 samples can be determined in duplicate by one person in a working day. The concentrations of HA measured by this method in different biological samples (human whole blood, plasma, urine, gastric juice and skin biopsies) were in good agreement with the values reported in the literature. The presence of minute amounts of N alpha-MH in the human gastric juice was established by rigorous checking.

Body Fluids↗
PubMed1985

Platelet serotonin and blood tryptophan in spontaneously hypertensive and normotensive Wistar-Kyoto rats.

The number of platelets and their content in serotonin (5-HT) were determined in 12-week-old spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP) and in normotensive Wistar-Kyoto rats (WKY). Spontaneously hypertensive rats had 49% more platelets and a 65% higher platelet 5-HT circulating pool than SHRSP and WKY. An increased synthesis of 5-HT by enterochromaffin cells in SHR is suggested by the lower level of plasma total and albumin-bound tryptophan and by the higher free/bound tryptophan ratio found in those rats, as compared with WKY. In SHRSP, a decrease of platelet survival time was reported, associated to an increased platelet production. This would explain the absence of variation of platelet number and 5-HT content.

Animals↗
PubMed1985

[Neuroendocrine tumors. Biochemical and physiopathological aspects].

Neuroendocrine tumors (secreting bioamines, peptides, hormones, prostaglandins...) represent rather homogeneous group since they correspond to a benign or malignant proliferation of cells belonging to the diffuse neuroendocrine system. This system might be considered as an extension of the concept (APUD System) proposed by Pearse to account for the common properties of these largely distributed cells. Among neuroendocrine tumors we focused since some years on apudomas and particularly carcinoïd tumors. The determination of their various secretion products in biological fluids allows the early and efficient detection of such tumors exhibiting a very slow growth. Finally the in vitro culture of carcinoïd cells appears to be of great interest in various research fields such as oncology, biochemistry and pharmacology.

Apudoma↗
PubMed1984

The cholesterol content of HDL2 and HDL3 subfractions of high density lipoproteins in different normocholesterolemic populations.

Two normocholesterolemic populations, selected for either high triglyceridemia or low HDL cholesterol content, both known to have increased artery disease risks, were studied for their cholesterol content in HDL2 and HDL3 subfractions. These subfractions were isolated by a precipitation method. The results showed that, in both populations, total HDL cholesterol values were similar and HDL2 and HDL3 cholesterol content were decreased when compared with a control population. In percentage of total HDL cholesterol, the HDL2 cholesterol subfraction appeared significantly diminished only in female subjects for both populations studied.

Adolescent↗
PubMed1984

[Determination of urinary xanthurenic acid after oral loading of L-tryptophan in 88 cases of photodermatosis].

Disturbances in the kynurenine pathway are present in pellagra and pellagroid syndromes. In 88 photodermatoses, the authors found increased urinary excretion of xanthurenic acid after oral load of tryptophan in a number of light-induced eruptions, i.e. benign summer photodermatosis (40%), polymorphous light eruptions (37%), and persistent light reactions (36%) as well as in patients with acute alcoholic intoxication. These biochemical abnormalities in the kynurenine pathway allow for a pathogenetic approach in some photodermatoses.

Administration, Oral↗
PubMed1984

[Blood serotonin and histamine in sheep with endemic scrapie: initial results].

The whole blood histamine levels of sheep without clinical scrapie but living in infected farms, control, and scrapie infected sheep are not significantly different. By contrast whole blood serotonin is decreased both in sheep living in infected farms and in scrapie-infected sheep as compared to controls. Thrombopenia may account for the hyposerotoninemia of sheep living in infected farms except those genetically linked to scrapie-infected sheep for which, as for scrapie-infected sheep, platelet serotonin appears also to be diminished. Whole blood serotonin determination might therefore be useful to detect sheep living in infected farms (these sheep probably play an important role in scrapie infection) and perhaps also humans with high susceptibility to Creutzfeldt-Jakob disease.

Animals↗
PubMed1984

[Plasma and saliva DST (dexamethasone suppression test) in depression. Clinical applications and kinetic approach].

Both plasmatic and salivary DST were simultaneously performed on a sample of 37 patients with a diagnosis of major depressive disorder (DMS III criteria): 22 primary depressions and 15 secondary depressions. Salivary DST showed a similar specificity but a decreased sensitivity in comparison with plasmatic DST. Essentially, the simultaneous use of both tests resulted in a better specificity for primary depression.

Adult↗
PubMed1983

[Role of platelet serotonin in common migraine. Concentrations and uptake].

Concentrations and uptake of platelet conjugated and unconjugated serotonin were measured in 15 healthy subjects and in 19 patients with common migraine. Venous blood was taken between migrainous attacks in all patients and during attacks in 8 of them. A significant decrease in unconjugated serotonin concentrations was observed during the attacks, whereas conjugated serotonin concentrations were the same as in controls. In addition, migrainous attacks were accompanied by a significant decrease in serotonin uptake by the platelets, with fall in Km, Vmax and -y. This abnormality was corrected when platelets removed from patients during attacks were incubated in plasma from controls, but it persisted when platelets from controls were incubated in plasma taken from patients during attacks. These findings suggest that one or several factors present in plasma are responsible for the decrease in serotonin uptake observed during migrainous attacks. Finally a study of correlations between these changes and the time elapsed since the last migrainous attacks demonstrated cyclic variations in abnormalities between attacks.

Adult↗