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Biomedical subjects

G Lyon

Publications and source records attributed to G Lyon.

At least 55 records · Page 3Linked to original sources
PubMed1979

Early histogenesis in the mouse cerebral cortex: a Golgi study.

The early histogenesis in the cerebral cortex of the mouse was studied with a modification of the rapid Golgi method. Three stages can be distinguished first, a period during which the telencephalon is exclusively populated with neuroepithelial cells (till E12); secondly the transient stage of the primordial cortical organization, characterized by the presence, in the outer part of the neural tube, of a loose network of primitive horizontal nerve cells and third, the appearance of the early cortical plate (E14) which contains closely packed, radial bipolar nerve cells. In addition to some salient morphological features of the various cell types, the technique also reveals the importance of efferent fibers from the cortex during the early cortical development.

Animals↗
PubMed1979

Aqueductal stenosis in X-linked hydrocephalus: a secondary phenomenon?

Two cases of x-linked hydrocephalus are reported. One underwent postmortem examination: serial sections of the brain stem failed to show stenosis of the aqueduct, the mean and minimal cross-sectional areas of which were normal. However, there were some morphological changes which were compatible with a mechanical compression of the brain stem. It is postulated that in the Bickers and Adams syndrome of x-linked hereditary hydrocephalus the primary defect is a communicating hydrocephalus leading usually, but not always, to aqueductal stenosis. The importance of electrophysiological investigations for the correct diagnosis of the characteristic clasped-thumb deformity is also indicated.

Cerebral Aqueduct↗
PubMed1979

[Acute polyradiculoneuritis in children. Clinical and developmental aspects. Prognostic factors apropos of 100 cases].

The main clinical features of acute infectious polyneuritis are described from a study of 100 cases. The distinction between Guillain-Barré syndrome and the atypical forms of the condition is arbitrary. In particular, the atypical features (pleocytosis, normal C.S.F. protein, relapses) had no influence on the final prognosis. In contrast, the severity of the distal neurological deficit, the duration of the acute illness, a late dissociation between the cells and proteins C.S.F., the age and sex were all statistically significant prognostic factors.

Acute Disease↗
PubMed1979

[Intramedullary tumors in children. Apropos of 30 cases].

Thirty cases of primary intramedullary tumours have been analysed (17 astrocytomas, 6 ependymomas, 6 non-glial tumours) and 10 have died. The long delay in diagnosis (more than 3 years) must be emphasised. The value of myelography, the natural history and treatment are discussed.

Astrocytoma↗
PubMed1978

Radial neuronal assemblies, ectopia and necrosis of developing cortex: a case analysis.

Reduced size of convolutions and midcortical laminar necrosis are approximately co-extensive in the cerebral hemispheres of a child, one of twins, dying at 18 months. Because the underlying laminar arrangement of neurons and the basic gyral pattern are normal, the cortical damage probably occurred not earlier than the third trimester of gestation. Neurons surviving above and below the zone of tissue necrosis, like their homologs in normal cortex, are entrained in multineuronal radial assemblies. Below the zone of necrosis the relative positions of radially adjacent neurons are unaltered. Above, however, in places where the molecular layer is reduced in width, neurons are displaced radially outward toward the pial surface. In places the pia is breached and bridged by a mesenchymal-glial cicatrix. Where this has happened neurons have migrated beyond the cerebral boundary and have established an ectopia in the subarachnoid compartment. These observations suggest that relatively undifferentiated intracortical neurons are held in radial assemblies by bonds which prevent their tangential displacment. The molecular layer appears to serve as a barrier to their radial displacement.

Cerebral Cortex↗
PubMed1978

[A new type of sialidosis with kidney disease: nephrosialidosis. II. Anatomic study].

The anatomical, macroscopical, histological, histochemical and ultrastructural findings in nephrosialidosis have certain similarities to those found in mucolipidoses. (Excess of complex lipid in neural tissue and an excess of light coloured material in the reticulo-endothelial system that is not easily characterised). Several distinct features help to distinguish nephrosialidosis from closely related conditions (renal lesions, storage of material in sympathetic ganglia).

Adolescent↗
PubMed1977

Acute measles encephalitis of the delayed type.

An acute measles encephalitis with epilepsia partialis continua occurred three months after measles in a previously healthy child with no detectable immunological defect. Levels of measles antibodies in serum and cerebrospinal fluid were high, and tubular inclusions of the type seen in subacute sclerosing panencephalitis were found in nerve cell nuclei. A communicating high-pressure hydrocephalus developed in the later stage of the disease. This case demonstrates that measles encephalitis of the delayed type should systematically be considered in children with acute encephalitis.

Acute Disease↗
PubMed1977

[Bournevilles tuberous sclerosis. clinical and genetic study of 59 cases in children].

The authors have studied 59 cases of Bourneville's tuberous sclerosis, including 44 sporadic cases from healthy parents and 9 familial patients. They stress the very high frequency of spasms in the infants of less than one year (80 %), the frequency and the early appearance of retinal phakomata and areas of depigmentation and the interest in the early detection of intracranial calcification. They discuss the specificity of the individual manifestations: cutaneous, retinal and systemic and they consider the problem of genetic counselling.

Adult↗
PubMed1976

Primary leiomyosarcoma of the lung in childhood.

Primary leiomyosarcomas of the lung and trachea are rare tumors. Only five cases have been reported in children (two of a lung, one of a mainstem bronchus, one of the carina, and one of the trachea). We report a new case in a 14-month-old boy and review the previous cases.

Brain Neoplasms↗
PubMed1976

[The effects of malnutrition on the prenatal development of rat brain].

Female rats were submitted to caloric and protein restriction 8 days before fecondation and during pregnancy. A reduction of the number of brain cells in the fetuses was evident only after the 20th day of pregnancy. This reduction appeared to be limited to glial cells, and not to affect neurons contrarily to what had previously been stated by some authors.

Animals↗