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S Oya

Publications and source records attributed to S Oya.

At least 73 records · Page 4Linked to original sources
PubMed1985

Precocious puberty and hypothalamic hamartoma. Report on a new case with ultrastructural data.

A new case of hypothalamic hamartoma associated with precocious puberty is presented. After reviewing the literature, 23 other cases appeared. The ultrastructural study of the present case revealed common features with other hamartomatous lesions of the central nervous system and with the gangliogliomas. The data suggest that these lesions are morphologically organized in a very similar manner despite their very different growing potential.

Child, Preschool↗
PubMed1982

Morphological study of human epileptic dendrites.

We studied 14 human epileptogenic foci with light and electron microscopy to establish their morphological patterns. Using silver staining techniques, we found dendritic areas devoid of spines, dendritic angulations, and nodular or segmentary dendritic swellings. When these findings were compared with the morphology of nonepileptic cortex, only the existence of dendritic swellings in the epileptic tissue was significant. Electron microscopy showed that the nodular dendritic swellings were due to an alteration in the normal arrangement of the microtubules. We hypothesize that an alteration in the microtubular arrangement causes a mechanical distortion of the dendritic membrane and subsequently may cause its depolarization.

Dendrites↗
PubMed1981

Tissue damage after chronic cerebellar stimulation.

Two spastic patients undergoing chronic cerebellar stimulation are studied. Biopsies taken after three months of stimulation showed various tissue changes when compared with those taken at the moment of electrode implantation. The most important alterations in the cerebellar cortex were adhesions round the electrodes, with a scarring reaction, gliosis, and loss of Purkinje cells. These findings resemble those described in various experimental reports of chronic cerebellar stimulation.

Adult↗
PubMed1981

Ependymal reaction after experimental spinal cord injury.

Images of ependymal cell proliferation after experimental spinal cord injury in the rabbit are presented. This finding suggests that segmental central canal obliteration after injury could be considered in the pathogenesis of posttraumatic syringomyelia.

Animals↗
PubMed1980

Long-term morphology of the alumina cream experimental epileptogenic focus.

A morpholigical study of an experimental epileptogenic focus in the cat, eighteen months after intracerebral injection of alumina cream, is presented. The most significant histological findings were cortical atrophy and reactive gloisis enclosing the implantedd particles. Subpial sclerosis and evidence of ischaemic neuronal lesions were also found. These findings confirm a close morphological relation between the alumina cream experimental focus obtained after a certain period of evolution and the human epileptogenic focus.

Aluminum↗
PubMed1980

Calcified telangiectatic hamartomas of the brain.

A case of calcified telangiectatic hamartoma in a 27-year-old patient having focal seizures is presented. The cases in the literature under the name of "hemangioma calcificans" are reviewed. Calcified telangiectatic hamartomas, as an anatomoclinical subgroup, are different from calcified cavernous angiomas.

Adult↗
PubMed1979

Medial frontal epilepsy: histological, histochemical, and ultrastructural study. Preliminary observations.

The authors have studied the histological, histochemical, and ultrastructural aspects of eight corticectomies of epileptogenic foci in the medial surfaces of frontal lobes. In all cases they were able to see more gliosis and fewer neurons than normal. The shape and number of dendritic spines were thought to be normal with the Golgi-Cox method. The histochemical study showed an increment of activity of Glucose-6-Phosphatase, Glucose-6-Phosphatedehydrogenase, adenosintriphosphatase, and acid phosphatase. The electron microscope showed, in every case, a variety of changes, among which the authors can point to perivascular lipid accumulation, and an increase of lipofuscin bodies in the cytoplasm of pyramidal cells.

Adolescent↗
PubMed1979

Chronic implanting of electrodes in the cerebellar vermis of the cat. Morphological findings.

The morphological modifications of the cerebellar cortex have been evaluated in eight cats with chronic electrodes implanted in the anterior vermis. In a control animal a silastic lamina without electrodes was implanted. Four animals received intermittent stimulations up to 11 hours in one case and 100 hours in the other 3. The stimulation was carried out with pulses of 0.5 msc, 200 cps, and a charge per phase of 0.68 muc. Microscopic examination of the cerebellum showed that the experimental implanting of prostheses of the cerebellar vermis produces tissue lesions consisting of fibrous reaction, imprinting of the cortex, gliosis, and loss of Purkinje cells. These lesions are independent of the electric stimulation, and seem to be related to the pressure of foreign material against the cortex.

Animals↗
PubMed1978

Cytological alterations in alumina cream experimental epilepsy.

The cellular changes in the neighbourhood of an alumina cream epileptogenic focus and in the mirror focus in chronic experiments in cats have been studied. According to the neuroglial morphology, four layers are described around the alumina cream lesion. At an ultrastructural level, and increase in gap junctions with a great amount of gliofilaments in astroglial processes are observed. There is a decrease in the number of neurons in the vicinity of the alumina cream. Some are coated by glial processes filled with gliofilaments. The dendrites of the pyramidal neurons in the mirror focus show long mitochondria. The possible significance of these data, in relation with the current theories about epileptogenicity, are discussed.

Aluminum Oxide↗
PubMed1978

Chronic paleocerebellar stimulation for the treatment of neuromuscular disorders. Four case report.

4 patients suffering severe neuromuscular diseases were subjected to a subtentorial implantation of electrodes over the anterior cerebellar lobe surface. Chronic stimulation was applied for 90 min to 7 h daily, with a rate of 20--180 Hz, 6--10 V and a schedule of 15 min "on", 15 min "off". Some improvement was observed in 3 patients treated with high frequency stimulation. 1 patient suffered seizures after three months of chronic stimulation. In 2 cases, posterior fossa explorations were necessary for revision of the stimulation apparatus and marked meningeal proliferation surrounding the electrodes was observed. Light and electron microscopic examination of the biopsies showed loss of Purkinje cells and gliofibrillar reaction. Effectiveness and side effects of chronic stimulation of the cerebellum are discussed.

Adult↗