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Biomedical subjects

J Jouve

Publications and source records attributed to J Jouve.

18 recordsLinked to original sources
PubMed2006

Metabolic responses to water deficit in two Eucalyptus globulus clones with contrasting drought sensitivity.

We compared the metabolic responses of leaves and roots of two Eucalyptus globulus Labill. clones differing in drought sensitivity to a slowly imposed water deficit. Responses measured included changes in concentrations of soluble and insoluble sugars, proline, total protein and several antioxidant enzymes. In addition to the general decrease in growth caused by water deficit, we observed a decrease in osmotic potential when drought stress became severe. In both clones, the decrease was greater in roots than in leaves, consistent with the observed increases in concentrations of soluble sugars and proline in these organs. In roots of both clones, glutathione reductase activity increased significantly in response to water deficit, suggesting that this enzyme plays a protective role in roots during drought stress by catalyzing the catabolism of reactive oxygen species. Clone CN5 has stress avoidance mechanisms that account for its lower sensitivity to drought compared with Clone ST51.

Adaptation, Physiological↗
PubMed2000

[Sagittal equilibrium of the pelvis: analysis of the inclination of the ischio-pubic ramus from the horizontal].

PURPOSE OF THE STUDY: The sagittal equilibrium of the spine and pelvis has been examined in numerous studies looking for the origin of certain posture disorders of the spine and the cause of lower back pain. Sagittal x-rays of the pelvis provide an analysis of the degree of inclination of the pelvis from the horizontal and the bi-coxo-femoral axis and information on the form of the sacrum. There is no radiographic parameter however which analyzes the transition between the pelvis-sacrum component and the femoral component, i.e. the periacetabular region. In the sagittal plane, a line tangent to the ischio-pubic ramus would appear to best reflect the orientation of the periacetabular region and the muscular forces applied to this region. The purpose of this work was to analyze the inclination of the ischio-pubic ramus from the horizontal and its relations with other sagittal radiographic parameters in a population of growing children with spinal disorders. MATERIALS AND METHOD: The study population included 100 children with spinal disorders who underwent a teleradiographic series with lateral view in the upright position. Most of the children had scoliosis (80 cases), 7 had kyphoscoliosis, 4 isthmic spondylolysis with spondylolisthesis, 1 spondylodiscitis and 4 lower back pain. Mean age was 13 years (range 2.5-22 years). We measured 7 radiographic parameters: lumbo-sacral angle, slope of the sacrum, pelvic version, incidence, thickness, overhang, and inclination of the ischio-pubic ramus from the horizontal. Data were analyzed to search for correlations between radiographic parameters and between radiographic parameters and clinical features. RESULTS: Mean inclination of the ischio-pubic ramus from the horizontal was 33.9 degrees (SD =5.9 degrees ). The only positive statistical correlation between the inclination of the ischio-pubic ramus and the clinical data was a relationship with the position of the arms compared with the horizontal (p =0.04). There was no correlation with age, sex, ethnic background, etiology. There was no correlation between the inclination of the ischio-pubic ramus and the other radiographic parameters (coefficient r ranging from 0.06 to 0.43). DISCUSSION: The interdependence of sagittal radiographic parameters of the pelvis and the spine have been largely demonstrated. Certain pathological situations (isthmic spondylolysis with spondylolisthesis, lower back pain, etc.) can be explained by the value of these parameters, particularly incidence. The inclination of the ischio-pubic ramus from the horizontal reflects the periacetabular region. When analyzed in the sagittal plane, it was found to be a more stable parameter, independent of most clinical criteria (particularly age, and etiology) and of the other radiographic parameters studied. The only determining factor appears to be acquisition of the upright position. The consistency of this parameter constrasts with the variability of the other radiographic parameters of the pelvis and the spine, particularly incidence, although the inclination of the ischio-pubis ramus is an expression of a region different than the pelvis. This study suggests that the periacetabular region plays a key role in acquisition of the upright position in humans. The periacetabular region would be a fixed point around which the lower limbs and spine describe varying orientations.

Adaptation, Biological↗
PubMed2000

[Febrile cytolysis disclosing hemorrhagic fever with renal syndrome].

We report the case of a 40-year-old-man who developed febrile cytolysis as the presenting sign of hemorragic fever with renal syndrome (HFRS). On admission, he had fever (40 degrees C) and epigastric pain. The AST level was at 2N, the ALT at 3N. There was a thrombocytopenia (61 000/mm(3)) without anemia or hyperleukocytosis. Three days after admission, the platelet count decreased to 40 000/mm(3), serum urea and creatinine increased from normal rate to 10.8mmol/l, 204.0 micromol/l, respectively. The HIV, HBV, HCV, leptospirosis antibodies were negative. The Hantavirus serology was positive (Ig G: 1/512). This case suggests that HFRS should be entertained as a possible cause of cytolysis with thrombocytopenia in patients with fever and no initial sign of renal involvement in North-Eastern France.

Adult↗
PubMed1992

Determination by high-performance liquid chromatography with electrochemical detection of free and conjugated N-acetyldopamine excretion in urine of children with neuroblastoma and nephroblastoma.

A simple method for the determination of N-acetyldopamine (NADA) (both free and conjugated) in children's urine by high-performance liquid chromatography with electrochemical detection has been developed. Conjugated NADA was measured as the free compound after enzymatic hydrolysis and purification on alumina. The total analysis time is 25 min. The results show a linearity of the whole assay from 0.005 to 20 mumol/l NADA; the sensitivity is 0.2 pmol per 20 microliters injected sample. Mean recoveries of 96.7 and 86.6% were obtained for free and total NADA, respectively. Modifications of the retention times (between 2 and 50 min) induced by changes in the eluent were determined. Conjugated NADA accounted for about 90% of the total excretion of NADA. These results suggest that this compound could play an important part in neuroblastoma; its concentration is thirteen times higher in children with neuroblastoma than in normal subjects.

Adolescent↗
PubMed1992

[Development in the metabolism of dopamine and its derivatives. Application to gross development disorders].

Dopamine (DA) and its metabolites homovanillic acid (HVA) in total, free and conjugated forms, dihydroxyphenylacetic acid (DOPAC) in total, free and conjugated forms, and 3 methoxytyramine (3 MT) levels were determined in the urine of autistic children from 2 years 8 months to 12 years of age and compared to those in normal children of identical age. Very significant group and age effects were found for DA, HVA and 3 MT. In the discussion, results are related to the hypothesis of a disorder in the maturation of the dopaminergic systems in infantile autism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Monoamines (serotonin and catecholamines) and their derivatives in infantile autism: age-related changes and drug effects.

Levels of dopamine (DA) and its derivatives homovanillic acid (HVA), 3-4 dihydroxyphenylacetic acid (DOPAC), 3-methoxytyramine (3MT) and norepinephrine+epinephrine (NE + E), and serotonin (5HT) and its derivative 5-hydroxyindolacetic acid (5HIAA) were determined from the urine of 156 autistic children aged two to 12 years 6 months, and compared with those of age-matched mentally retarded non-autistic and normal controls. Very significant group and age effects were found for DA, HVA, 3MT, NE + E and 5HT. High HVA, 3MT, NE + E and 5HT levels were found in autistic and non-autistic children. The DA, HVA, 3MT, NE + E, 5HT and 5HIAA levels decreased significantly with age in the three groups. Significantly decreased levels of DA and HVA were observed in autistic children on haloperidol, compared with non-medicated autistic children. The results are discussed in relation to the hypothesis of a maturation defect of monoaminergic systems in autism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Determination of urinary vanillactic acid and plasma dihydroxyphenylalanine as markers of non-secreting neuroblastoma by high-performance liquid chromatography with electrochemical detection.

An accurate and precise isocratic high-performance liquid chromatographic technique for the analysis of urinary vanillactic acid (VLA) and plasma dihydroxyphenylalanine (DOPA), especially at low concentrations (pmol/l) for VLA and nmol/l for DOPA), is described. The compounds were purified in a single step, (on an anion exchanger for VLA and on aluminium oxide for DOPA), separated by ion-pair reversed-phase liquid chromatography, and detected electrochemically. A single analysis was complete within 18 min. Mean recoveries of 103 and 81% were obtained for VLA and DOPA, respectively, and the limits of detection were 42 and 76 pmol/l, respectively. The mean values of the intra-assay coefficient of variation were 14 and 7.1% for VLA and DOPA, respectively, and the mean values of the inter-assay coefficient of variation were 15.7 and 11.6%, respectively. Modifications of the retention times (between 2 and 42 min) induced by changes in the eluent were determined. Reference values for normal children and children with neuroblastoma or various tumours are given.

Adolescent↗
PubMed1989

Urinary dopamine metabolites as indicators of the responsiveness to fenfluramine treatment in children with autistic behavior.

Modifications in serotonin and dopamine metabolism were evaluated in 13 children with autistic behavior and related to their responsiveness to fenfluramine treatment. A double-blind medication-placebo crossover design was used. Each patient received 1.5 mg/kg fenfluramine daily for 3 months followed and preceded by placebo for 1 month. Clinical improvement was observed in 6 children (responders). It included reduction of behavioral symptoms such as motor activity, anxiety, mood disturbances, and distractibility. Modifications of serotonin (5-HT), dopamine (DA), and DA metabolites [homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC)] were assessed at urinary levels. Responders and nonresponders showed a significant decrease of urinary 5-HT levels on fenfluramine. The main differences between the two groups of subjects were found with HVA, the major metabolite of DA. Fenfluramine significantly increased HVA levels in responders whereas no significant modification was found in nonresponders. Moreover the initial level of HVA (lower in responders) significantly differentiated the two groups. These results suggest that the clinical response to fenfluramine could be related to the dopaminergic action of this drug and that urinary DA metabolite levels could be considered as indicators of the responsiveness to fenfluramine treatment in children with autistic behavior.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

Auditory evoked potential modifications according to clinical and biochemical responsiveness to fenfluramine treatment in children with autistic behavior.

Evoked potentials to auditory stimulations varying in intensity were studied in 13 children with autistic behavior treated with fenfluramine. Modifications of both amplitude and single-trial potential variability were considered according to the clinical and biochemical responsiveness to this drug. Six children (responders) were clinically improved by the treatment. Electrophysiological data were affected according to the clinical and biochemical responsiveness to fenfluramine: the auditory evoked potential amplitude increased, and the single-trial potential variability decreased at each intensity level only in responders whose dopaminergic metabolism was significantly modified by fenfluramine treatment. No modification was found in nonresponders. Both biochemical and electrophysiological results argued for an amphetamine-like action of fenfluramine in those autistic children whose attention deficits are associated with motor disturbances including hyperactivity.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Urinary homovanillic acid levels of autistic children.

Anomalies in dopamine metabolism were investigated by assaying total homovanillic acid, and its free and conjugated fractions, in the urine of 34 autistic, 34 normal and 34 mentally retarded children. An increase in total homovanillic acid in autistic and retarded children is apparently due to an increase of free homovanillic acid in the autistic group and to an increase of conjugated homovanillic acid in the retarded group. Further research needs to be carried out into the central origin of homovanillic acid and to establish its relevance to autistic children.

Autistic Disorder↗
PubMed1987

[High-amplitude auditory evoked potentials as a function of the intensity of stimulation. Relation to dopaminergic metabolism].

Relationships between augmenting/reducing (aug/red) in auditory modality and dopaminergic metabolism were investigated in young normal adults. Auditory evoked potentials (AEP) to tones (750 Hz, 200 msec) varying from 50 to 80 sB SPL were recorded at Cz and Fz sites. Individual differences in dopaminergic metabolism were estimated by assaying homovanillic acid levels in urines (u-HVA). The slopes values of P1, N1 and P2 amplitude changes with increasing stimulus intensities were used to evaluate the relationships between aug/red and u-HVA levels. The results of this study showed significant negative correlations between the aug/red of the N1 component recorded at Fz site and the u-HVA concentrations: the higher the aug/red slopes (augmenting tendency), the lower the u-HVA levels. In fact, the main result was that this finding was in accordance with previous ones relating aug/red to HVA when assayed in cerebrospinal fluid (CSF). Our data also showed that in further studies on auditory aug/red, the interest should be focused on the N1 component at Fz site.

Acoustic Stimulation↗
PubMed1986

Frontal auditory-evoked potential augmenting-reducing and urinary homovanillic acid.

Relationships between augmenting-reducing (Aug/Red) in auditory modality and dopaminergic metabolism were investigated in young adults with respect to sex. The slope values of evoked potential amplitude changes with increasing intensities were used to evaluate Aug/Red both at Cz and Fz for each of the five components: P1, N1, P2, P1N1, N1P2. The greatest slopes (Aug) were found in females. Individual differences in dopaminergic metabolism were estimated by assaying free and conjugated forms of homovanillic acid (HVA) in urines. HVA excretion rates were significantly more variable in males than in females. Relationships between Aug/Red and HVA levels were only found in males. The lower the Aug/Red slopes recorded at Fz site for the N1 component (weak augmenter or reducer responses), the higher the urinary HVA level and particularly the conjugated forms of HVA. These results are of interest for further applications in psychopathology.

Adult↗
PubMed1983

High-performance liquid chromatography with electrochemical detection for the simultaneous determination of the methoxylated amines, normetanephrine, metanephrine and 3-methoxytyramine, in urine.

A simple method for the simultaneous analysis of normetanephrine, metanephrine and 3-methoxytyramine (both free and conjugated) in human urine by reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection has been developed. Existing methods have been optimized for extraction by study of analytical parameters. The hydrolysed urines are purified and concentrated by successive passages on two ion-exchange resins and ammoniacal elution to eliminate interference from pigments or related chemical compounds. The methoxyamines are separated by high-performance liquid chromatography on a reversed-phase column. Detection and quantitation are achieved with an electrochemical detector using a vitreous carbon electrode. Samples can be injected at 25-min intervals. Reference values of adults and children are given.

Adolescent↗
PubMed1983

[Monoamine and monoamine enzyme abnormalities in childhood autism].

According to monoaminergic hypothesis of psychosis, several symptoms observed in child autism may be related to anomalies of cerebral amines and/or synaptic dysfunctioning. The main amines concerned are serotonin and dopamine which are synthetized and catabolized following similar schemes. Methyl-indolamines production, mentioned in adult schizophrenia, has not been observed in child autism. Similarly, monoaminoxydase diminution has been observed in adults and not in children. Hyperserotoninemia does exist in some cases of child autism. Results concerning dopaminergic systems are more promising. The autistic behavioral syndrome suggests a dopaminergic dysfunctioning. Enhancement of homovanillic acid, the main metabolite of dopamine, has been found both in cerebrospinal fluid and in urines of some autistic children. Moreover, modifications of dopamine-beta-hydroxylase, an enzyme that changes dopamine into noradrenaline, have been mentioned in some cases of autism. A better definition of the autistic clinical syndromes associated with a more systematic study of monoamines plasmatic and urinary derivates will allow, in the near future, a better understanding of child autism and a clearer definition of therapeutic indications.

Amino Acids↗
PubMedDate not supplied

[Clinical (behavior scale items), electrophysiologic (conditioned evoked potentials) and biochemical (urinary homovanillic acid) markers in infantile autism].

Infantile autism is a behaviorally defined syndrome. Many investigators suggest that it is probably related to a brain dysfunctioning in which catecholamine metabolism is involved. The aim of the following paper is to study the validity of different clinical and biological markers of this syndrome: 1. clinical scores using a behavioral rating scale, 2. amplitude and variability of conditioned auditory evoked potentials, 3. urinary levels of homovanillic acid. The response of these markers in autistic children treated with vitamin B6 and magnesium have been assessed. The relationships found between clinical and biological data are discussed. It can be expected that such an approach would contribute to a better understanding of the underlying mechanism of autism.

Autistic Disorder↗