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Biomedical subjects

E Flachaire

Publications and source records attributed to E Flachaire.

14 recordsLinked to original sources
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↗
PubMed1989

A controlled study of Dextran 40: effect on cerebral blood flow and metabolic rates in acute head trauma.

A controlled double-blind evaluation of the effects of Dextran 40 at different concentrations on cerebral blood flow (CBF), cerebral oxygen consumption (CMRO2) and cerebral lactate production (CMRLact) was carried out. We studied 40 patients in coma due to recent head injury. Concentrations of Dextran solution were not significantly related to variations in CBF and metabolic rate over the period of infusion. The lack of effect of the Dextran infusion may be explained by the absence of global brain ischemia in these patients at the time of the study. The very low initial CBF values were a consequence of brain metabolic depression and not a sign of global ischaemia. The rheological benefits of treatment with Dextran 40 in head injured patients should preferably be investigated using techniques which permit detection of local changes in CBF and metabolism.

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↗
PubMed1983

Assessment of the benzethonium chloride method for routine determination of protein in cerebrospinal fluid and urine.

We have tested the characteristics of the method of Iwata and Nishikaze (Clin Chem 25: 1317, 1979). The linearity, sensitivity, and precision are satisfactory and the reactivity of benzethonium chloride with various proteins (albumin, immunoglobulins) is the same. The method has been compared with Meulemans's technique (Clin Chim Acta 5: 757, 1960), routinely used in our laboratories, by analysis of 82 samples of cerebrospinal fluid (CSF) and 119 samples of urine. Our results for cerebrospinal fluid agree well with those of Iwata and Nishikaze (r = 0.976; y = 0.992x - 0.013), but we find their method unsuitable for urinary protein determination, probably because of interfering compounds in urine.

Albumins↗
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↗
PubMedDate not supplied

[Platelet serotonin concentrations in autistic children and members of their families].

Children with early infantile autism have often high platelet serotonin (5 HT) levels. According to this fact, we wondered if a genetic abnormality of 5 HT metabolism could be detected in family members of autistic children. We has thus determined platelet 5 HT levels in these children's mothers, fathers and siblings. It is noteworthy to find out that: autistic children have a mean platelet 5 HT level significantly higher than their siblings' (p less than 0.01); fathers' levels are significantly lower (-29%; p less than 0.001) than those of other family members' and of control group. Furthermore, for future purposes, we studied platelet 5 HT levels at different times during pregnancy in controls and in a woman already mother of an autistic child. We observed a raise (+31%; p less than 0.01) in platelet 5 HT during the first trimester of the pregnancy with a lowering towards normal levels during the eight month, in the woman with an autistic child as well as in the controls.

Autistic Disorder↗
PubMedDate not supplied

[Classification of chronic psychoses types I and II and platelet serotonin levels. Apropos of 38 cases].

The authors have examined, within a population of 38 patients, all suffering from chronic psychosis, the concentration of serotonin in the blood platelets as a function of a psychopathologic classification. The 38 patients, 17 men and 21 women, with a mean age of 46 years, diagnosed as schizophrenics (INSERM classification) were categorized according to their specific psychosis (types I and II of J. Guyotat) on examination of their clinical reports by two independent clinicians. This categorization returned 20 psychotics of type I, 16 psychotics of type II and 2 psychotics were difficult to classify. Blood samples were taken from both patients and from 47 controls at 10 o'clock in the morning, two hours after breakfast. The concentration of serotonin in the blood platelets was subsequently examined using the technique of liquid chromatography. The results obtained did not show any significant difference between the chronic psychotics and the control group. The average level of platelet serotonin is 5.09 for psychosis of type I and 3.56 for psychosis of type II, but the value of this difference does not indicate a significant statistical difference; however the tight grouping of serotonin levels in the psychotics of type II looked interesting because they were similar to those of the control in being more homogeneous than those of the psychotics of type I.

Blood Platelets↗