Search PubMed⌕ Search

Biomedical subjects

C Chiron

Publications and source records attributed to C Chiron.

At least 73 records · Page 4Linked to original sources
PubMed1993

The potential for increasing seizure frequency, relapse, and appearance of new seizure types with vigabatrin.

Although generally effective, various antiepileptic drugs have been reported on occasion to increase seizure frequency, result in seizure relapse, or elicit new types of seizures. Some seizure types and epilepsy syndromes appear more prone than others to exacerbation by a given drug. Vigabatrin is rarely associated with seizure worsening, and then mainly in patients with resistant generalized epilepsies.

Aminocaproates↗
PubMed1993

Dopaminergic D2 receptor SPECT imaging in Rett syndrome: increase of specific binding in striatum.

A dopamine deficiency has been implicated in Rett syndrome, a progressive encephalopathy in girls that involves movement, tonus and cognitive disorders. To test the hypothesis that striatal D2 receptors increase in number in early stages of the disease, we measured the binding potential of 123I-Iodolisuride, a specific D2 ligand, in eleven Rett children aged 4-15 yr (7.9 +/- 3.5 yr) (mean +/- s.d.) and eight control subjects aged 3.5-13 yr (8.1 +/- 3.8 yr) who exhibited other neurological disorders. Regional cerebral blood flow (rCBF) was also measured with SPECT using 133Xe. The binding potential for 123I-ILIS and D2 receptors was significantly higher in Rett (0.45) than in controls (0.23) (p < 0.01). An increase in 123I-ILIS binding due to increased rCBF in patients' striata was excluded. Our results are consistent with a higher density of D2 receptors in young patients suffering from Rett syndrome because of reduced dopaminergic neurotransmission.

Adolescent↗
PubMed1992

Unlayered polymicrogyria and agenesis of the corpus callosum: a relevant association?

Three anatomical cases of unlayered polymicrogyria associated with agenesis of the corpus callosum and heterotopias are presented. The cortical dysplasia includes: (1) thin unlayered cortical mantle with radial disposition but no horizontal organisation of the neurons; (2) microgyria with fused molecular layers; and (3) persisting transitory cells in the molecular layer (Cajal-Retzius cells, subpial granular layer). A Golgi study of the cortex in one case shows abnormal orientation of the neuronal dendritic tree in the superficial area along the fused molecular layers. Heterotopias are of two types: scattered neurons in the subcortical region and in layer I; and nodular heterotopias in the paraventricular region and in centrum semi ovale. This type of cortical dysplasia differs from the classical four-layered microgyria and is similar to the cortical anomalies described in Aicardi syndrome. One case presented here has Aicardi syndrome, while the two others, one girl and one boy, do not meet the criteria for Aicardi syndrome; in particular, they do not display chorioretinal lacunae. Nevertheless, this neuropathological association is responsible for severe mental retardation and epilepsy, and incites the search for a genetic origin like that in Aicardi syndrome.

Abnormalities, Multiple↗
PubMed1992

Early diagnosis of severe myoclonic epilepsy in infancy.

Of 329 epileptic patients referred in a six year period with the first seizure occurring in the first year of life, 20 met the following criteria: generalized seizures excluding infantile spasms, myoclonic, tonic or absence seizures, at least one afebrile seizure, normal development prior to the first seizure, normal CT scan, and no etiology. Seventeen of these 20 patients developed the full pattern of severe myoclonic epilepsy in infancy (SMEI). This syndrome was recognizable from the second or third seizure in the first year of life, although epileptiform EEG abnormalities were lacking until the age of 11 to over 30 months. Therefore, based on the clinical pattern, the diagnosis of SMEI can be made with quite good reliability by the end of the first year of life.

Electroencephalography↗
PubMed1992

Changes in regional cerebral blood flow during brain maturation in children and adolescents.

Regional cerebral blood flow (rCBF) was studied by SPECT using 133Xe in 42 children, aged 2 days to 19 years, considered as neurologically normal. rCBF was measured on cortical regions and on the cerebellum and thalamus. Curves for reference values and standard deviation were defined for each region. At birth, cortical rCBFs were lower than those for adults; after birth they increased until 5 or 6 yr of age to values 50%-85% higher than those for adults and thereafter decreased, reaching adult levels between 15 and 19 yr. Neonatal values of rCBF on cerebellum and thalamus were slightly higher than adult level, but not significantly; after age 1, they followed the common pattern for cortical curves. When rCBFs were expressed in percent global CBF, they were lower at birth than adult levels in the cortex, then increased and reached a plateau corresponding to the adult value before the second year of age. The time needed to reach normal adult values differed for each cortical region. The shortest time was found on the primary cortex and the longest on the associative cortex. Cognitive development of the child seems to be related to changes in blood flow of the corresponding brain regions.

Adolescent↗
PubMed1991

A serial study of regional cerebral blood flow before and after hemispherectomy in a child.

Hemimegalencephaly (HME) is a severe unilateral brain malformation the prognosis of which may be improved by hemispherectomy. HME also provides a unique opportunity to compare normal and pathological hemispheric function in the same patient. We performed a serial functional cerebral imaging study in a child suffering from a neuropathologically confirmed left HME. He was hemispherectomized at 11 months because of intractable epilepsy; this led to cessation of seizures and dramatic psychomotor improvement. Regional cerebral blood flow (rCBF) was studied at 1, 7, 10, 12 and 25 months with single photon computed tomography (SPECT) using 133-Xenon and with simultaneous EEG recording. At one month of age SPECT was performed ictally. During left EEG discharges, rCBF was 40% higher on the left hemisphere than on the right, even in occipital and frontal regions, usually immature at this age. A crossed cerebellar hyperperfusion was also found. At 7 and 10 months, SPECT was performed interictally; rCBF was 45% lower in the left hemisphere than in the right. During follow-up, global and regional CBF values showed normal levels and normal maturation in the right hemisphere except for a mild and transient decrease observed one month after hemispherectomy. SPECT provides an additional procedure for studying hemispheric function in vivo. Serial SPECT imaging may be useful for the preoperative and postoperative evaluation in unilateral cerebral malformation.

Brain↗
PubMed1991

Treatment of infantile spasms with intravenous gamma-globulins.

In a prospective study, 23 children with infantile spasms received intravenous gammaglobulins in high doses. 19 patients present a West syndrome. 4 older patients were included in the study because infantile spasms had preceded their Lennox-Gastaut syndrome. None of the patients had recently undergone corticosteroid therapy. No effect was observed in 15 patients, while transitory clinical and/or electroencephalographic improvement was noted in 3. Complete normalization was obtained in the remaining 5 patients, of whom 4 had severe brain lesions. No correlation existed between the therapeutic results and immunological abnormalities, a deficiency in IgG subclasses in particular. On the whole, the therapeutic results were disappointing. But the existence of some cases in which spectacular electroencephalographic and/or clinical improvement was obtained leads us to suggest that IV gamma-globulins be used as auxiliary treatment in infantile spasms.

Electroencephalography↗
PubMed1991

Vigabatrin in childhood epilepsy.

Sixty-six children with various types of severe drug-resistant epilepsy were entered into a long-term, dose-rising study of vigabatrin after a 4-week run-in placebo period. All the children were receiving one to three other antiepileptic drugs, the doses of which were not changed during the 6-month dose titration phase. Following the introduction of vigabatrin, 11 patients became seizure free, and 28 responded with a greater than 50% reduction in seizure frequency. The following types of epilepsy responded favorably in order of decreasing efficacy: cryptogenic and symptomatic partial epilepsy, other symptomatic generalized epilepsy, and Lennox-Gastaut syndrome. However, three of nine patients with myoclonic epilepsy showed an increase in seizure frequency. Optimal responses were found with vigabatrin doses of 40 to 80 mg/kg/day, although no significant adverse effects were noted with doses of higher than 100 mg/kg/day. Thirty-eight responders continued on vigabatrin, 19 of whom have been treated for more than 1 year, with generally good efficacy. As a result of discontinuing concomitant antiepileptics, six patients are on monotherapy with vigabatrin, four of whom are seizure free. Vigabatrin tolerability was good, with 39 of 66 children reporting no adverse effects. Hyperkinesia was reported in 17 patients (26%), and two had to drop out of the study. All these patients had a history of hyperkinesia or mental retardation. In patients in whom vigabatrin dose was reduced because of hyperkinesia, a dose increase could later be instituted without recurrence of symptoms. There was no change in neurologic examination and no drug-related abnormalities in clinical laboratory data.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Therapeutic trial of vigabatrin in refractory infantile spasms.

Infantile spasms usually start during the first year of life and constitute one of the most difficult types of epilepsy to treat. They carry a very poor prognosis for both epilepsy and mental development. Seventy children, including 47 infants, with intractable infantile spasms were entered into an open study with vigabatrin as add-on therapy to the usual anticonvulsant treatment. All were resistant to previous treatments, including corticosteroids (43 patients), carbamazepine, benzodiazepines, and sodium valproate. Two children withdrew from the study because of intolerance to vigabatrin (hypotonia or hypertonia) before evaluation of efficacy could be made. Of the remaining 68 children, 29 (43%) showed complete suppression of spasms. Forty-six children had a greater than 50% reduction in spasms. The best response was observed in those with tuberous sclerosis (12/14 compared with 12/18 with symptomatic infantile spasms of other origin and 22/36 with cryptogenic infantile spasms). Following the initial response to treatment of these patients (n = 68), a long-term response was confirmed in 75% of children with symptomatic infantile spasms and 36% of children with cryptogenic infantile spasms. In eight children, all other anticonvulsant medication could be definitively withdrawn. Tolerability appeared excellent, with 52 of 70 patients reporting no side effects. Somnolence, hypotonia, weight gain, excitation, and insomnia were the most common problems at the beginning of the study and were usually transient. Given the poor prognosis of this type of childhood epilepsy, vigabatrin appears to be a very interesting advance in the management of drug-resistant infantile spasms.

Adolescent↗
PubMed1990

["Benign" form of myoclonic epilepsy in children].

Among 62 children with myoclonic epilepsy who had first seizures between 1 and 10 years, without clinical or radiological evidence of brain lesion, we selected the 16 patients who had exhibited several types of fits and had stopped having seizures for over two years. First seizures occurred between 18 months and 4 years, and they were generalized clonic, tonic-clonic or tonic. After a mean 3 months' period, patients started also to have absence and myoclonic fits. During the period with various types of seizures, that lasted a mean 10 months, patients were ataxic and hyperkinetic, and 11 of them suffered myoclonic absence status for several hours or days. The EEG showed a high voltage rhythmic slow-wave activity with spikes, differing from the slow spike wave tracing of the Lennox-Gastaut syndrome, and there was no photosensitivity. The mean duration of the epilepsy was 1 year and 4 months and the last seizures were convulsive, occurring mainly during sleep. The clinical and EEG pattern, the high familial incidence are shared by the Doose syndrome, of which the present series seems to be a subgroup, as are other well-defined syndromes: benign and severe myoclonic epilepsies of infancy.

Child, Preschool↗
PubMed1990

Pharmacokinetics of the individual enantiomers of vigabatrin (gamma-vinyl GABA) in epileptic children.

1. The pharmacokinetics of the enantiomers of vigabatrin were investigated after oral administration of a single 50 mg kg-1 dose of the racemate to two groups of six epileptic children (I: 5 months-2 years, II: 4-14 years). 2. The mean (+/- s.d.) values of maximum plasma concentration and area under the plasma concentration-time curve of the R(-) enantiomer were significantly higher than those of S(+) vigabatrin in both groups: R(-) Cmax: 21 +/- 6.6 (I)-41.3 +/- 13.9 (II) vs S(+) Cmax: 13.9 +/- 4.5 (I)-23.8 +/- 12.2 (II) mg l-1; R(-) AUC: 106 +/- 28.5 (I)-147 +/- 34 (II) vs S(+) AUC: 90.9 +/- 27.9 (I)-117 +/- 26 (II) mg l-1 h. In group I, the half-life of the R(-) isomer was significantly shorter than that of the S(+) isomer; in group II, the half-lives were comparable. 3. For the R(-) enantiomer the area under the curve, and the elimination half-life increased linearly with age. 4. During chronic administration (50 mg kg-1 vigabatrin racemate twice a day for 4 days), the morning trough plasma drug concentrations did not increase.

Adolescent↗
PubMed1989

Electron microscopic and Golgi study in a case of hemimegalencephaly.

Pathological findings in a case of hemimegalencephaly are presented. Hemispherectomy, performed because of intractable seizures, allowed an electron microscopic and Golgi study. Glial abnormalities consisted of hyperplasia of glia cells with giant astrocytes often containing several nuclei and proliferation of numerous Rosenthal fibers. Golgi stain showed many giant neurons with a perikaryon covered by perisomatic processes, and a complex dendritic tree. Glial abnormalities could be correlated with the firmness of the hemisphere and intense hypersignal on magnetic resonance imaging. Giant neurons were associated with an increase in size of the perikaryon and dendritic tree; this pattern suggests a polyploidy.

Brain↗
PubMed1989

Regional cerebral blood flow by SPECT imaging in Sturge-Weber disease: an aid for diagnosis.

Regional cerebral blood flow (rCBF) was studied using SPECT (single photon emission computed tomography) with 133-Xenon in 13 patients with confirmed Sturge-Weber disease, aged 9 months to 18 years. CT scan, performed at the same time, showed evident cerebral angioma in 10 but not in three. A marked hypoperfused area was found in all patients, ranging from -32% to -72% and of the same location as the CT signs. The hypoperfusion seems to result from post ictal phenomenon as well as from chronic ischaemia. SPECT imaging is therefore a sensitive method for visualising intracranial angioma in Sturge-Weber disease and it provides an aid for diagnosis when a CT scan is not reliable.

Adolescent↗
PubMed1989

Study of the cerebral blood flow in partial epilepsy of childhood using the SPECT method.

Cerebral functional imaging methods provide information on the location of the epileptic focus in partial epilepsy of adults. We report our experience of one of these methods, single photon emission computed tomography (SPECT), in epilepsy of children. SPECT enables the regional cerebral blood flow (rCBF) to be measured, after inhalation or injection of 133-Xenon, on 5 contiguous, 20 mm thick axial sections, with a 14 mm resolution and negligible brain irradiation. In Sturge-Weber syndrome (13 patients aged 9 months to 18 years) the rCBF was reduced in the same territory as CT abnormalities suggesting ischaemia of the brain tissue lying below the pial angioma; the SPECT image facilitated the diagnosis in 3 patients with atypical CT. In hemimegalencephaly (6 patients aged 1 month to 10 years) the rCBF was extremely low in the hypertrophic hemisphere and in 1 case the SPECT image was determinant in the decision to perform hemispherectomy. In partial epilepsy with normal CT and/or MRI (42 children aged 1 to 15 years) the rCBF was abnormal in 83% of the patients, and its abnormality was located in the same area as the EEG focus in three quarters of the cases. Between seizures, the rCBF was low in 3 out of 4 cases and abnormality decreased after the seizures had ceased (6 patients explored twice); it was high in 1 out of 4 cases. Thus, in children as in adults, cerebral functional imaging provides new data which contribute to the localization and follow-up of epileptic foci.

Adolescent↗
PubMed1989

Electroencephalographic aspects of hemimegalencephaly.

The authors retrospectively studied the electroencephalograms (EEGs) of 12 patients with hemimegalencephaly-a unilateral brain malformation which is often overlooked, despite having typical CT-scan and MRI aspects. They were characterized by three types of abnormal tracing, which correlated with prognosis: triphasic complexes of large amplitude were observed in patients with the earliest onset of seizures, and were associated with the most severe prognosis; unilateral, rhythmic 'alpha-like' activity was recorded in patients with seizures occurring after three months of age, and was associated with a relatively favourable outcome; asymmetrical suppression-bursts characterised by 'alpha-like' activity on the abnormal side were seen in patients with infantile spasms. The EEG pattern seems to make an important contribution to both diagnosis and prognosis.

Brain↗