Search PubMed⌕ Search

Biomedical subjects

B Garreau

Publications and source records attributed to B Garreau.

At least 37 records · Page 2Linked to original sources
PubMed1992

Regional cerebral blood flow in childhood autism: a SPECT study.

OBJECTIVE: The authors investigated a possible cortical brain dysfunction associated with infantile autism. METHOD: They measured regional cerebral blood flow with single photon emission computed tomography (SPECT) and xenon-133 in 21 children with primary autism (according to DSM-III-R criteria). Five cortical brain areas including frontal, temporal, and sensory association cortices were examined in order to test the recent hypothesis of cerebral dysfunction in primary autism. Anatomical references for each subject were obtained with computerized tomography or magnetic resonance imaging and were used to delimit the regions of interest for SPECT analysis. RESULTS: When the results from the group with primary autism were compared with an age-matched group of nonautistic children with slight to moderate language disorders (N = 14), no cortical regional abnormalities were found. CONCLUSIONS: It appears that there is no regional cortical dysfunction in primary autism; however, in light of methodological limitations, one cannot exclude the possibility of more localized or subcortical brain dysfunctions in autism.

Autistic Disorder↗
PubMed1992

[Demonstration of cerebral lateralisation disorder in autistic children: study of auditory reactivity by transcranial pulsed Doppler].

Transcranial Doppler Ultrasonographic recordings of the middle cerebral arteries were performed on children with autistic behavior (AUT), compared to retarded children without autistic behavior (NON-AUT) and normal children (NOR). Blood flow measurements (resistance index) were performed at rest and during auditory stimulations. Compared to NOR and NON-AUT, significant differences of the resistance index were found in AUT on the left side, thus suggesting differences in metabolic mechanisms evoked by auditory stimulations. This result confirms the hypothesis of abnormal development of cerebral lateralization in autism.

Autistic Disorder↗
PubMed1991

Phytoestrogens: new ligands for rat and human alpha-fetoprotein.

The binding of the lignans, enterolactone, enterodiol, nordihydroguaiaretic acid (NDGA), and the isoflavonic phytoestrogen equol, to human and rat alpha-fetoprotein (AFP) was studied. They had differential inhibitory effects (NDGA greater than equol greater than enterolactone greater than enterodiol) on the binding of estrone and estradiol to rat AFP and the binding of unsaturated fatty acid to both rat and human AFP. Inhibition was dose-dependent. The apparent dissociation constants (Kd) for phytoestrogens binding to AFP were: Kd NDGA = 5 +/- 1.2.10(-7) M, Kd equol = 6.7 +/- 0.8.10(-6) M, Kd enterolactone = 1.7 +/- 0.4.10(-5) M and Kd enterodiol = 2.2 +/- 0.6.10(-5) M. The Kd for estrone binding to rat AFP was increased by increasing concentrations of equol, but the number of esterone binding sites remained unchanged. This, plus the results of double-reciprocal plots, suggests that they compete for the same site(s). NDGA also competitively inhibited estrone binding at low NDGA concentrations (increased Kd), but high concentrations induced conformational changes in rat AFP, as both Kd and the number of binding sites (n) were altered. Both rat and human AFPs underwent changes in electrophoretic behaviour and loss of immunoreactivity with increasing NDGA, suggesting that NDGA binding induces conformational changes in the AFPs. However, equol did not alter the electrophoretic or immunological properties of either rat or human AFP, providing further evidence for qualitative differences in the effects of these diphenols. These findings indicate that phytoestrogens could play a role in AFP-dependent normal and pathological growth and development.

4-Butyrolactone↗
PubMed1991

Autism and family home movies: preliminary findings.

Preliminary analyses of 12 home movies taken by parents before the recognition of autistic disorders of their own child confirm the major value of this method for describing early signs: anomalies of eye contact, deficient variability of emotional expression, defect of attention and initiation of communication, motor abnormalities, etc. The possibilities of subsequently using these documents in a research context are described: behavior assignment with a rating scale, comparative analysis with movies of normal children, blind examination, and scoring by investigators not informed of the diagnosis.

Activities of Daily Living↗
PubMed1990

The Behavioral Summarized Evaluation: validity and reliability of a scale for the assessment of autistic behaviors.

The Behavioral Summarized Evaluation (BSE), is a 20-item paper-and-pencil rating scale specifically designed for the measurement of behavioral parameters which could be related to biological data in autistic children involved in educational programs, neurophysiological studies, and therapeutic trials. The development of the scale, the validity, and reliability studies are presented in this paper. The results suggest that the BSE is an acceptable tool for the assessment of autistic behaviors, easy to handle, and accessible to both professionals and paraprofessionals of the medico-educative staff. It is a useful addition to the bioclinical researcher's evaluation battery for bioclinical and therapeutic studies. However, more work is suggested to further investigate the psychometric properties of this behavior assessment instrument.

Adolescent↗
PubMed1990

[Autism in infants and young children. The value of early diagnosis].

Clinical studies of early symptoms are among the most significant advances achieved during recent years in the field of autism. The first descriptions of early symptoms were retrospective and lacked precision. Autistic children are now being seen increasingly early and new insight is being gained into the initial manifestations and differences in clinical patterns. Similarly, differential diagnosis problems (borderline forms) are changing as clinicians evaluate children at younger ages. Although a definitive diagnosis is neither possible nor even desirable before the age of 18 to 24 months, detailed clinical data should be collected early. This data forms the basis for differential diagnosis and will be needed later for differentiating various clinical patterns of developmental disorders, establishing a prognosis, and monitoring therapeutic effects. In prospective longitudinal studies of autistic children, comparison of recent observations with detailed early data is essential. Early initial evaluation includes videotape recordings, assessment of cognitive functions and communication skills, and use of a scale for autistic symptoms. Using the results of evaluations of very young children, a specific semiology (communication disorders) can be developed. Several symptoms probably denote neurophysiologic and/or perceptive disorders. Primary symptoms are now being better distinguished from secondary anomalies (behavior disorders) that may be avoidable or treatable.

Age Factors↗
PubMed1989

Electrophysiological effects of fenfluramine or combined vitamin B6 and magnesium on children with autistic behaviour.

The authors compared the effects of fenfluramine or combined vitamin B6 and magnesium treatment on the evoked potential conditioning of 12 children whose autistic behaviour had improved clinically following treatment. The children who were clinically sensitive to combined vitamin B6 and magnesium developed a conditioning phenomenon and the fenfluramine-sensitive children showed an enhancement of the Cz evoked response amplitude. Results are discussed with reference to behaviour modifications observed during treatment.

Autistic Disorder↗
PubMed1989

[Measurement of cerebral blood flow by transcranial Doppler ultrasonography in children presenting with autistic behavior. Preliminary results].

Transcranial Doppler ultrasonographic recordings of the middle cerebral arteries were performed on eight children with autistic behavior compared to eight controls. Blood flow measurements were assessed at rest and during auditory and visual stimulations. The main result was obtained during the auditory stimulations and concerned the left artery blood flow which is lower in autistics than in controls in these conditions (p less than .02). This result confirms the possibility of a left hemisphere dysfunctioning in autistics and may be related to clinical features as language disabilities and paradoxical reactivity to auditory stimuli.

Acoustic Stimulation↗
PubMed1988

Urinary free and conjugated catecholamines and metabolites in autistic children.

Urinary catecholamines (DA, NE, E) and their main metabolites (HVA, DOPAC, MHPG) were analyzed both as free and conjugates in eight children diagnosed as autistic according to DSM-III criteria and eight normal children. Significant differences appeared for the urinary excretion of both DA and NE and their respective metabolites: Autistic children showed low DA, high HVA, high NE, low MHPG urinary levels. These results are consistent with previous findings on altered catecholamine metabolism in autistic children. They suggest that autistic behaviors might be related to an abnormal functional imbalance among monoamines either at a molecular level or at a system level. Furthermore, they emphasize the special interest of urinary assays in pediatric research.

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

Auditory evoked responses and their modifications during conditioning paradigm in autistic children.

Auditory evoked responses (AERs) were recorded from 16 autistic children (ages 2-10 years) and age-matched normal and retarded controls. In order to test the ability to form auditory-visual cross-modal associations, often impaired in autism, the effects on AERs of coupling sound and light were studied with a paradigm that did not require the cooperation of the subject. Several differences between groups were found concerning the frequency and the amplitudes of present AERs. The pattern characterizing the effects on AERs of coupling sound and light (conditioning phenomenon) was observed for both autistic and normal controls, and not for retarded children. Results suggest that autistic children may have a real but slow learning ability.

Acoustic Stimulation↗
PubMed1987

[Significance of clinical and biological markers in autistic syndromes in children].

Several biological theories were proposed to explain symptoms of childhood autism in terms of monoamine metabolic dysfunction. Clinical, electrophysiological and biochemical markers which support the dopaminergic hypothesis will be given in this paper. A factorial analysis, performed on the 'behavior summarized evaluation' (BSE, scoring behavioral data), exhibits a first component corresponding to the autistic DSM III criteria, and also shows that the disturbances of attention and perception belonged to this component. So, as well as communication, selective attention, perception and gestures, usually considered as regulated by the dopaminergic system are deeply modified and appeared as primary symptoms in autistic syndromes. Many electrophysiological data recorded in autistic children suggest both faulty modulation of sensory input and deficiency in dealing with sensory cross-modal association which have been related to a dysfunctioning of the dopaminergic system. Elevated homovanillic acid levels, the main dopamine metabolite, have been attributed to a reduced re-uptake of dopamine related to a 'longer occupation' of the receptors which is in agreement with the electrophysiological 'sensory overload'. The relationships found between these markers are discussed. Such an approach would contribute to a better understanding of the underlying mechanism of autism.

Autistic Disorder↗
PubMed1986

Dopamine-beta-hydroxylase (DBH) and homovanillic acid (HVA) in autistic children.

In the present study, plasma DBH activity and urinary HVA levels were measured in 19 autistic and 15 normal children. DBH activity was significantly elevated in the 8 less retarded autistic patients. In this subgroup, a negative correlation was found between plasma DBH and urinary HVA levels. These results support the hypothesis of a possible involvement of brain catecholamine dysfunction in the production of autistic symptoms.

Age Factors↗
PubMed1985

Vitamin B6, magnesium, and combined B6-Mg: therapeutic effects in childhood autism.

This article reports the behavioral, biochemical, and electrophysiological effects of four therapeutic crossed-sequential double-blind trials with 60 autistic children: Trial A--vitamin B6 plus magnesium/magnesium; Trial B--vitamin B6 plus magnesium; Trial C--magnesium; and Trial D--vitamin B6. Therapeutic effects were controlled using behavior rating scales, urinary excretion of homovanillic acid (HVA), and evoked potential (EP) recordings. The behavioral improvement observed with the combination vitamin B6-magnesium was associated with significant modifications of both biochemical and electrophysiological parameters: the urinary HVA excretion decreased, and EP amplitude and morphology seemed to be normalized. These changes were not observed when either vitamin B6 or magnesium was administered alone.

Autistic Disorder↗
PubMed1985

Frontal auditory evoked potentials and augmenting-reducing.

Auditory evoked potentials (AEPs) to tones (750 Hz--200 msec) ranging from 50 to 80 dB SPL were studied at Cz and Fz leads in 29 normal adults (15 males) ranging in age from 20 to 22. Peak-to-trough amplitudes were measured for the P1-N1 and the N1-P2 wave forms as well as baseline (500 msec prestimulus)-to-peak amplitudes for each component, i.e., P1, N1 and P2. Amplitudes were examined as a function of intensity and electrode location. Cz-Fz amplitude differences increased with increasing stimulus intensity, the differentiating peak being the N1 component. An overall reducing phenomenon was found at Fz in the 70-80 dB range whereas an augmenting effect was observed at Cz for these intensities. The augmenting/reducing groups defined by analysis of individual amplitude-intensity patterns were different whether we considered Fz or Cz results: Fz reducers were more numerous than Cz reducers. These results on prominent reducing at the frontal level were examined in relation to the data concerning the modulatory function of the frontal cortex on auditory EPs. Implications were drawn for the role of the frontal cortex in cortical augmenting-reducing.

Adult↗