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O Robain

Publications and source records attributed to O Robain.

At least 19 recordsLinked to original sources
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

Microgyric and necrotic cortical lesions in twin fetuses: original cerebral damage consecutive to twinning?

Extensive cortical necrosis associated with malformative microgyric-like lesions and with necrotic lesions of the white matter was observed in two male 25 week fetuses. These cases differed from previously reported cases of brain damage in monozygotic twins: both fetuses were affected and the lesions occurred early in pregnancy, before the end of neuronal migration, thus resulting in a cortical malformation associated with destructive lesions.

Adult↗
PubMed1992

Neurological findings and seizure outcome in children with bilateral opercular macrogyric-like changes detected by MRI.

The authors studied 10 patients aged between six and 23 years (mean age 14 years 5 months) with magnetic resonance imaging, which detected bilateral 'macrogyric-like' maldevelopment of the insulo-opercular regions. The data confirm that biopercular gyral anomaly, associated with mental retardation, pseudobulbar palsy (cortical or central) and epilepsy, represents an anatomo-clinical syndrome. Nevertheless, a wide clinical spectrum was found varying from pictures correlating with the topography and extent of the MRI-detected anomaly to conditions indicating wider cerebral involvement. Epilepsy, varying greatly in age at onset and severity, consistently influenced the prognosis for five patients with diffuse EEG abnormalities and intractable seizures with falls. Anterior callosotomy relieved such seizures in one case.

Adolescent↗
PubMed1992

Epilepsy and focal gyral anomalies detected by MRI: electroclinico-morphological correlations and follow-up.

The authors studied 10 patients (mean age 15 years 6 months) with localized developmental gyral disorder detected by MRI. There were two groups of major malformations. Seven patients (group 1) had unilateral 'macrogyric-like' insulo-opercular changes, one of whom died early in life and had extensive microgyria. The six others had mental retardation and epilepsy, three of whom had focal neurological signs. Age at onset of epilepsy varied greatly. Clinical and EEG data suggested a wider cerebral involvement than recognized on MRI. The remaining three patients (group 2) had abnormal gyri of variable topography and extension, with bulging grey matter and ventricular deformity. One had mental retardation, another had neurological signs. All had intractable complex partial seizures and focal EEG anomalies correlating with the MRI lesion site, pointing to a well-defined epileptogenic zone. No clinical or EEG evidence of significant malformation in the remaining brain tissue was observed. Ablative surgery was beneficial for one patient; focal cortical dysplasia was the pathological substrate.

Adolescent↗
PubMed1991

Cerebral lymphoma and HIV encephalitis in a case of paediatric AIDS, with pre-existing multicystic encephalomalacia.

A case of intracerebral malignant B cell lymphoma associated with encephalitis typical of Human Immunodeficiency Virus (HIV) infection is described in a 4 year old child, with post-transfusion Acquired Immune Deficiency Syndrome (AIDS) and severe pre-existing cystic encephalomalacia. This report further documents B cell lymphoma as the commonest cause of an intracerebral mass, and an important cause of death in paediatric AIDS. That more than one pathological process may be responsible for neurological symptoms in paediatric AIDS is also emphasised.

AIDS Dementia Complex↗
PubMed1991

Bilateral porencephalic defect in a newborn after injection of benzol during pregnancy.

Porencephaly is usually considered to be a prenatal brain lesion due to a circulatory failure. We report a case of bilateral porencephaly with heterotopia and absence of the septum pellucidum in a newborn. The mother had received several injections of benzol during pregnancy with an intent of inducing abortion. The possibility of a causal relationship between the administration of benzol and the occurrence of the defect is supported by the existence of previously reported cases of cerebral malformations following maternal exposure to organic solvents.

Abnormalities, Drug-Induced↗
PubMed1991

[Congenital hereditary motor and sensory neuropathy].

The authors report 6 cases of hereditary sensorimotor neuropathy (HSMN) presenting with the following clinical features: (1) severe outcome (3 out of 6 patients died before the age of 4 years), and (2) intellectual impairment (3 out of 6 cases). Histopathological study of nerve biopsies gave heterogeneous results: there was one case of axonal neuropathy (HSMN II of Dyck and Lambert), one case of demyelinating neuropathy with Schwann's cell proliferation (HSMN III of Dyck and Lambert), and one case of giant axonal neuropathy. The last three cases displayed an original pattern hitherto unknown in classical delayed HSMN, with complete disappearance of myelinated sheaths and Schwann's cell proliferation. This particular pattern did not seem to be due to the biopsy being performed at an early stage, since in one case a second biopsy showed the same histological features.

Female↗
PubMed1990

GABAergic mechanisms in the CA3 hippocampal region during early postnatal life.

The developmental pattern of GABAergic neurons in the rat hippocampus during the first week of postnatal life shows several particularities both from a morphological and physiological point of view: (1) GABA immunoreactive neurons which are initially localized in a deep and superficial layer, progressively disappear from these two layers. From the end of the first postnatal week, GABAergic neuronal somata appear throughout the whole hippocampus, but GABA immunoreactive terminal structures are not frequent until the second postnatal week. (2) Intracellular observations in slices reveal the presence in CA3 pyramidal neurons between P0 and P6 (postnatal days) of spontaneous giant depolarizing potentials (GDPs); these are mediated by GABA acting on GABAA receptors and modulated presynaptically by NMDA receptors. During this period of development, GABA and GABAA analogues have a depolarizing action at resting membrane potential. Bicuculline at this developmental stage blocks completely spontaneous and evoked synaptic potentials. During the second postnatal week, when GABA responses shift from depolarizing to hyperpolarizing, bicuculline induces spontaneous interictal discharges. It is suggested that the positive feedback of the GABAergic interneuron on the pyramidal neuron during the first week of life may account for the generation of GDPS which may play an important role in synaptogenesis.

Action Potentials↗
PubMed1990

Kearns-sayre syndrome. Two clinico-pathological cases.

Two clinico-pathological cases of Kearns-Sayre syndrome are reported. In both cases the typical triad (progressive external ophthalmoplegia, heart block, retinitis pigmentosa) was present and spongiosis was the main pathological finding. In one case there was also a marked capillary proliferation, significance of which is discussed. A deletion of the mitochondrial DNA was found in the muscle, spinal cord and brain of this last case.

Adolescent↗
PubMed1990

[Joubert's syndrome].

We report a new case of pathologically documented Joubert syndrome. A review of 35 published cases showed that this syndrome, first described by Joubert and Eisenring in 1969, is well individualized and exhibits consistent features, including attacks of tachypnea alternating with respiratory pauses, abnormal ocular movements, severe psychomotor retardation, and ataxia. Anatomic anomalies include vermian agenesis with cystic dilatation of the fourth ventricle. Inheritance of this condition is autosomal and recessive. Onset is in the neonatal period and prognosis is severe. Significant anatomic resemblances with the Dandy-Walker syndrome exist, although genetic and clinical features are different. The origin of this syndrome is unknown, but a study of peroxisomes is required since three cases of Joubert syndrome with pipecolic acidemia have been reported and resemblances exist between some recognized peroxisomal diseases and Joubert syndrome.

Cerebral Ventricles↗
PubMed1990

[Delayed measles encephalitis in a leukemic child].

A case of measles encephalitis of the delayed type in a 5 year-old girl is reported. The encephalitis occurred 6 months after a measles which supervened just after the 18th monthly reinduction treatment for acute lymphoblastic leukemia. The child died one month later. This measles inclusion body encephalitis (MIBE) was confirmed by the presence of intracellular inclusions in the brain cells visualized by electron microscopy. The evidence of viral related intracellular nucleocapsides was confirmed by in situ hybridization. These nucleocapsides were identical to those seen in subacute sclerosing panencephalitis.

Child, Preschool↗
PubMed1989

Distribution of GABAergic neurons in late fetal and early postnatal rat hippocampus.

The ontogenesis of GABAergic neurons in the rat hippocampus was studied using an anti-GABA serum. GABA immunoreactivity appeared at the 18th day of gestation. At this stage, GABA-immunoreactive (GABA-IR) cells are grouped in two layers, one located deeply in the intermediate zone near the ventricular zone, and the other found superficially in the marginal zone near the hippocampal fissure. During the late embryonic and early postnatal life, GABA-IR neurons progressively disappeared from these two layers. The transient appearance of an abundant network of GABAergic neurons might be due to transient expression of GABA in some neurons or to cellular death. Later on, from the third postnatal day, the GABA-IR neurons appeared throughout the whole hippocampus according to a dorsoventral and lateromedial gradient. The setting of neuronal bodies preceded that of GABA-IR puncta (supposed to be mainly synaptic boutons) around the neuronal cell bodies and along the dendritic shafts. The puncta are only visible from the sixth day onwards and their number increased rapidly during the first 3 postnatal weeks. Our results indicate that GABA may have a role in neurotransmission in the hippocampus from a very early stage of development.

Aging↗
PubMed1989

Selective destruction of mossy fibers and granule cells with preservation of the GABAergic network in the inferior region of the rat hippocampus after colchicine treatment.

Lesions induced by colchicine injection into the rat hippocampus were investigated by means of electron microscopy and GABA immunocytochemistry. Granule cells were nearly completely destroyed 3 days after colchicine injection; since the necrosis of their axonal endings was delayed, an anterograde degeneration of the mossy fibers had probably taken place. The selectivity of the lesions was not limited to granule cells, for some pyramidal neurons in CA1 pyramidal layer were damaged. It was, however, striking to observe that throughout the hippocampal structure GABAergic neurons were spared from the effects of colchicine. For instance, GABAergic neurons were found in the vicinity of the completely destroyed granule cell layer. GABAergic neurons and terminals were also present in the CA3 region where the GABA-containing terminals formed a dense network of synapses with somata and dendrites of pyramidal cells. It was interesting to note that, consistent with previous studies, the GABAergic neurons in CA3 are innervated by mossy fibers. We conclude that after colchicine treatment the destruction of the granule cells was not associated with a lesion of the GABAergic network. This selective lesion provides a useful model with which to study the properties of CA3 neurons deprived of their major excitatory input but with an intact inhibitory network.

Animals↗
PubMed1989

Hippocampal plasticity in childhood epilepsy.

Quantitative autoradiography was used to study changes in high affinity (Kd = 12 nM) binding sites for kainic acid, a marker of mossy fibers, in the hippocampus of childhood epileptics. We found a highly significant increase in the density of kainate binding sites in the CA3 region and in the fascia dentata in childhood epileptics as compared to age matched controls. We suggest that anatomical plasticity occurs in the hippocampus of human epileptics as in experimental models of epilepsy. The increase in kainate binding sites may contribute to the development of epileptic seizures.

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↗