Search PubMed⌕ Search

Biomedical subjects

C Quincy

Publications and source records attributed to C Quincy.

At least 19 recordsLinked to original sources
PubMed1993

Dot-blot immunodetection of antibodies against GM1 and other gangliosides on PVDF-P membranes.

A simple and rapid assay for detection of antibodies against GM1 and other gangliosides (GM3, GM2, GD1a, GD1b, GT1b, GD3) is described. Purified gangliosides were applied individually in 1 microliter of methanol to polyvinylidene difluoride (PVDF) membranes. Anti-ganglioside antibodies in human sera were allowed to bind and were revealed with a second antibody coupled to peroxidase. The specificity of antibodies binding to gangliosides was confirmed using established techniques to detect anti-ganglioside antibodies such as immunostaining of gangliosides after high performance thin layer chromatography according to Derrington et al. (1989) and ELISA procedure according to Adams et al. (1991) or using the ability of cholera toxin beta subunit to remove GM1 bound antibodies. The dot-blot assay is the simplest and quickest method to run and it appears to be suitable for large routine screening detection of anti-ganglioside antibodies in sera of patients with neurological diseases.

Animals↗
PubMed1993

Platelet serotonin content and free and total plasma tryptophan in healthy volunteers during 24 hours.

The determination of platelet serotonin (5-HT) and plasma tryptophan concentrations is useful in the diagnosis, investigation of etiologies, and treatment of psychiatric disorders. To determine the usual circadian variations in platelet 5-HT and free and total tryptophan concentrations, we measured these variables during 24 h at 1-h intervals and every 30 min from 2000 to 0800 in seven clinically healthy young men with an HPLC method. No common circadian rhythm for platelet serotonin concentrations was observed in our subjects; however, there was a distinct rhythm for both free and total plasma tryptophan: Concentrations were maximal in the afternoon and minimal during the night.

Adult↗
PubMed1991

Increased serotonin platelet uptake after tianeptine administration in depressed patients.

Tianeptine is a new antidepressant drug reported to enhance serotonin (5-hydroxytryptamine [5-HT]) uptake in rat brain. The effect of tianeptine on 5-HT platelet uptake was studied in 10 depressed patients treated for 28 days. Tianeptine increases Vmax of 5-HT platelet uptake during treatment without inducing any change in Km. As early as 2 hr after the first administration, Vmax increased significantly (+23%, alpha = 0.01). Although of a lesser magnitude, 5-HT platelet uptake remains increased after chronic administration (+14% on day 10 and +13% on day 28). This suggests that tianeptine affects 5-HT platelet uptake sites, either directly or via an action on modulators of 5-HT uptake. These results, in contrast with the action of other tricyclic antidepressants, confirm the original action of tianeptine on 5-HT platelet metabolism.

Adolescent↗
PubMed1991

[Platelet serotonin concentration in children under 5 years of age].

High platelet serotonin concentrations have been reported in children with early infantile autism. However, as yet there are no reference values regarding platelet serotonin in normal infants and young children so that it remains difficult to define the exact significance of this finding. We report here with the platelet serotonin concentration found in 57 infants and children (20 girls, 37 boys) ranging in age from 10 days to 5 years old. Our results show that mean platelet serotonin concentrations in infants and young children are significantly greater than mean values obtained in older children (+11%) and neonates in the umbilical cord (+64%). No significant variations were found relating to sex, leucocyte count and platelet count. There therefore appears to be a physiological elevation of platelet serotonin concentration in infants and young children, and this has to be taken into consideration in the interpretation of the elevated values found in cases of infantile autism.

Aging↗
PubMed1990

Determination of reference values for serotonin concentration in platelets of healthy newborns, children, adults, and elderly subjects by HPLC with electrochemical detection.

We adapted a high-performance liquid chromatographic method with electrochemical detection (Clin Chim Acta 1984;139:1-12) to the determination of platelet serotonin. We used this method to determine platelet serotonin reference values in a healthy population, measuring platelet serotonin concentration in the following subjects: 31 newborns (16 girls, 15 boys); 41 children (11 girls, 30 boys), ages 20 months to 15 years; 56 adults (26 women, 30 men), ages 20 to 58 years; and 20 elderly subjects (16 women, four men), ages 65 to 94 years. There was no significant difference in platelet serotonin concentration between sexes in each age group. However, significant changes (P less than 0.001) were observed between the newborns (mean +/- SD: 1.67 +/- 0.74 nmol/10(9) platelets) and the children (4.09 +/- 1.04) or the adults (3.81 +/- 0.87). Moreover, the platelet serotonin concentration in the elderly subjects (2.57 +/- 1.12) was significantly (P less than 0.001) lower than in the adults and children and significantly higher (P less than 0.01) than in the newborns. Such age-related differences must be taken into consideration when data from neurological or psychiatric patients and control subjects are compared.

Adolescent↗
PubMed1988

[Evaluation of the treatment with fenfluramine of autism in children].

The effects of fenfluramine were studied in a group of 44 children with the autistic syndrome and in 26 non autistic children with behavior abnormalities, mostly hyperkinetic children, as a control group. The mean daily dosage was 0.65 mg/kg/day. There were 75% positive results in the autistic children and 77% in the control group. The clinical improvement appears to be mainly related to the control of the hyperactive behavior in the autistic children. Platelet serotonin levels were studied in both groups, showing a clear cut decrease during fenfluramine therapy with no significant differences between the 2 groups and no correlation between the clinical effects and the magnitude of the decrease.

Ambulatory Care↗
PubMed1987

[Lecithin cholesterol acyltransferase (LCAT) and lipid cardiovascular risk factors in hemodialysis patients].

In order to study the reliability of plasma LCAT activity as a marker of cardiovascular risk, we compared 66 chronic hemodialysis patients with a control group (n = 72) and a coronary artery disease (CAD) patients group (n = 46). The decrease of LCAT activity (measured by the Nagasaki method) did not appear as a marker of CAD risk; if this activity was effectively lower in 51 of the hemodialysis patients (p less than 0.001) than in the patients of the control group, it was higher in CAD patients (p less than 0.001). In the remaining 15 hemodialysis patients, we found an almost undetectable LCAT activity, not accompanied by a change in esterification percentage when compared with the other hemodialysis patients; the mixing of these serums with control group restored an enzymatic activity and excludes the presence of an inhibitor. The only risk factors common to hemodialysis and CAD patients was the decrease of HDL cholesterol and the high frequency of combined hyperlipoproteinemia.

Cholesterol↗
PubMed1984

Liquid chromatographic determination of homovanillic acid, 5-hydroxyindoleacetic acid and probenecid levels in human cerebrospinal fluid during probenecid test.

Homovanillic acid and 5-hydroxyindoleacetic acid, respectively the major metabolites of the central neurotransmitters dopamine and serotonin, are present in human lumbar cerebrospinal fluid, and their determination during the probenecid test is used to study brain monoamine abnormalities in man. We developed a high performance liquid chromatographic technique coupled with electrochemical detection which allows the simultaneous determination of homovanillic acid and 5-hydroxyindoleacetic acid on 10 microliter of human lumbar cerebrospinal fluid. Another liquid chromatographic technique coupled with ultra-violet detection was applied to the measurement of probenecid after injection of 10 microliter of native cerebrospinal fluid. The main advantages of these two techniques are their simplicity, sensitivity, rapidity (five cerebrospinal fluid samples are analysed within one hour) and their good day-to-day reproducibility . These methods were applied to probenecid tests performed in several neurological patients.

Adolescent↗
PubMed1983

Plasma lipoproteins and fatty acid composition after "minipill".

A study of the effect of a low-dose oral contraceptive, Adepal (ethinyl estradiol and levonorgestrel, 30 and 150 micrograms on the 5th to 12th, 40 and 200 micrograms on the 13th to 28th, respectively) on the blood lipids, lipoproteins and fatty acid composition has been conducted on 13 young women before and after six months of treatment. All together, total cholesterol concentration did not vary; however, the high cholesterol values decreased whereas the low cholesterol values increased with the pill. Triglyceride levels increased significantly (p less than 0.001). High density lipoprotein (HDL)-cholesterol decreased clearly (p less than 0.001) regardless of the cholesterol value at the beginning; low and very low density lipoprotein (LDL + VLDL)-cholesterol increased slightly, as well as the apoprotein B (Apo B) concentration (p less than 0.05). The lipoprotein electrophoresis showed intermediate bands (IDL) in 5/12 of the women after treatment. The three major classes of lipoprotein showed some variations in the fatty acid composition after the oral contraceptive; in any lipid class from any lipoprotein, the linoleic (18: 1 omega 6), arachidonic (20: 4 omega 6) and eicosapentaenoic (20: 5 omega 3) acids decreased whereas the palmitic (16: 0) and oleic (18: 1 omega 9) acids increased. Our results suggest that a low-dose contraceptive like Adepal produces, nevertheless, some significative modifications of plasma lipids and lipoproteins.

Adult↗
PubMed1983

[Valve of the use of benzethonium chloride for turbidimetric analysis of cerebrospinal fluid proteins with an automatic analyzer].

We have adapted Iwata and Nishikaze's benzethonium chloride turbidimetric method for the assay of CSF proteins to the techniques of continuous flow and the centrifuge analyser. The proposed technique presents several advantages: benzethonium chloride forms a stable precipitate with the proteins with a slow kinetic of formation, enabling adaptation to the centrifuge analyser; the response obtained is identical for albumin and immunoglobulin G; this very sensitive technique allows the use of micro-samples. Studies of repeatability and the correlations made with other techniques give very satisfactory results.

Autoanalysis↗
PubMed1982

Enzyme-linked immunoadsorbent assay for serum IgE: evaluation in four centres.

We report an evaluation of a commercially available kit, the Biomérieux IgE-kit, for determination of total IgE in serum by the EIA double antibody sandwich method. Results by this procedure and PRIST (Pharmacia) show a degree of association (r) of 0.98 and a regression equation of log Y = 0.79 log PRIST + log 3.31. Correlation between the IgE kit and RIST shows a degree of association of 1.00 and a regression equation of log Y = 1.01 log RIST--log 1.05. Between-laboratory standard deviations are 3%, 3%, and 15% for the IgE concentrations of, respectively, 83, 285, and 900 IU/ml. Similarly, intra- and inter-assay correlations were performed on 60 lyophilised serum samples tested in the four centres. No protein interference was found except for cryoprecipitates. The favourable correlation with existing procedures and the feasibility of this kit offer a new way of measuring IgE levels.

Alkaline Phosphatase↗
PubMed1980

Determination of ketoprofen in biological fluids by reversed-phase chromatography.

A sensitive and specific high-performance liquid chromatographic method was developed for the determination of ketoprofen [2-(3-benzoylphenyl)propionic acid] in plasma and urine. The method includes an extraction of the drug and the internal standard [2-(4-benzoylphenyl)butyric acid] into ether from acidified plasma. The organic phase is evaporated, and the residue is dissolved in the mobile phase (acetonitrile-0.02 M phosphate buffer, pH 3) (45:55). A 20-microliter aliquot is analyzed on a reversed-phase column. The accuracy is within 1.5% for therapeutic concentrations, and the coefficients of variation are 5.5 and 3.4% for 2 and 10 micrograms/ml, respectively. For the urine assay, the accuracy is within 3%, and the cofficients of variation are 1.9 and 1.7% for 3 and 50 micrograms/ml, respectively. This method was applied successfully to the determination of ketoprofen in humans for pharmacokinetic studies.

Acetonitriles↗
PubMed1979

[Sensitive method for continuous detection of peptides and proteins using the biuret reaction and a copper-Sephadex reactor (author's transl)].

We describe a detection method relying both on the copper displacement from a Sephadex gel by peptides and proteins, and on the subsequent colorimetric determination of the complexed copper. The system described is fully automated and it permits a continuous analysis of column effluents. The choice of cuprizone as a detecting reagent for copper, enables one to bring the detection limit down to 200 ng for albumin and 60 ng for alanylglycylglycin. The specificity of the method is the same as the biuret reaction. Some examples of the possible applications are given.

Biuret Reaction↗