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Biomedical subjects

G Lelord

Publications and source records attributed to G Lelord.

At least 55 records · Page 3Linked to original sources
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

The presence or absence of certain behaviors associated with infantile autism in severely retarded autistic and nonautistic retarded children and very young normal children.

The modified Behavior Observation Scale adapted from Freeman et al. was used to compare normal, retarded, and autistic children with very low developmental ages and to determine the types of behavior that could differentiate these three diagnostic categories of children. Examination of the data revealed that there was much more overlap between autistic and retarded children than between autistic and normal children. However, a behavioral pattern of autism could be delineated and very retarded autistic children could be distinguished from the nonautistic retarded children. The autistic behavioral pattern included subclusters of symptoms that might be interpreted as disturbances of sensory modulation and motility.

Age Factors↗
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↗
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

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↗
PubMed1986

Comparison of clinical diagnoses and Rimland E2 scores in severely disturbed children.

The Rimland E2 questionnaire was applied to three groups of children for whom clinical diagnoses of Infantile Autism, Autism with Associated Symptoms, and Mental Retardation had been made, as well as to normal controls. The results confirm that the Rimland scale is accurate in differentiating autistic from nonautistic children. But the scale does not appear to permit clear differentiation of infantile autism from autism with associated symptoms, and the more typical autistic children (diagnosed as Kanner's EIA) did not all yield high scores. Several possible explanations for this fact are put forward.

Adolescent↗
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↗
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↗