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S Oya

Publications and source records attributed to S Oya.

At least 55 records · Page 3Linked to original sources
PubMed1993

Experimental neurocytomas.

Four ethyl-nitrosourea (ENU)-induced oligodendroglioma-like tumors of the rat showing large rosettes on haematoxylin-eosin stain were studied by means of immunohistochemistry and electron microscopy, and their features compared with six human intraventricular neurocytomas. The similarities between the experimental and human tumors studied support the hypothesis that most of the so-called ENU-induced oligodendrogliomas in the rat are primitive neuroectodermal tumors with the tendency to differentiate toward a neuronal phenotype, and also suggest that the ENU-model of neurocarcinogenesis is useful for the induction of experimental neurocytomas.

Animals↗
PubMed1993

Tumor-infiltrating lymphocytes expressing IOT-10 marker. An immunohistochemical study of a series of 185 brain tumors.

The presence of IOT-10-positive lymphocytes among the tumor-infiltrating-lymphocyte (TIL) population was studied in a series of 185 brain tumors. In most of the tumors, IOT-10-positive lymphocytes were identified, but generally they were scarce and masked among the tumor cells, suggesting that NK-cells exercise a poor participation in the tissular response against brain tumors. Isolated tumor cells showing IOT-10-positivity were found in low-grade astrocytomas, neurinomas and medulloblastomas. IOT-10-positivity on both tumor neuropil and tumor cells was considered a characteristic finding in oligodendrogliomas. The number of IOT-10-positive NK-cells in brain metastases and in cerebellar hemangioblastomas was comparatively greater than in other types of brain tumor. Since in brain metastases, the presence of IOT-10-positive NK-cells can be related to the tissular response to an extracerebral malignancy, their considerable presence in cerebellar hemangioblastomas is an enigmatic finding that deserves further attention.

Antigens, Neoplasm↗
PubMed1992

Delayed transplantation of foetal cerebral tissue into injured spinal cord of adult rats.

Delayed transplantation of foetal cerebral tissue into injured spinal cord of adult rats was performed for the purpose of evaluating the usefulness of the procedure for reconstructing the spinal cord and providing motor recovery. Transplanted tissue showed a survival rate greater than 80% and integration with the host tissue. Nerve fibers of the host surrounded the transplanted tissue, penetrating it. Foetal cerebral neurons matured into recipient spinal cord, but they were not organized in layers. The experience obtained suggests that delayed transplantation of foetal cerebral tissue into contused spinal cord is useful in morphological spinal cord reconstruction. Nevertheless, at least during the first two months after transplantation, clinical assessment of motor recovery showed no differences between transplanted and nontransplanted rats.

Animals↗
PubMed1992

Expression of neuronal markers in the so-called ENU-induced schwannomas.

The present data show that the so-called ENU-induced malignant schwannomas express neuronal markers. This finding supports the hypothesis that a population of tumor cells in these neoplasms are neuroblastic in nature, and suggests the classification of ENU-induced schwannomas as primitive neuroectodermal tumors.

Animals↗
PubMed1992

Synaptophysin expression in "ependymal tumors" induced by ethyl-nitrosourea in rats.

Synaptophysin expression was studied in seven "ependymomas" induced by transplacental administration of ethyl-nitrosourea in rats. In all the cases, strong positivity for synaptophysin was found on tumor cells. This finding supports previous studies suggesting that ENU-induced brain tumors considered to be ependymal neoplasms, are, in fact, primitive neuroectodermal tumors.

Animals↗
PubMed1992

Influence of recombinant interleukin-2 and tumor necrosis factor-alpha on the development of ethyl nitrosourea-induced brain tumors.

Using the experimental model of brain tumors induced by ethyl-nitrosourea (ENU), human recombinant interleukin-2 (rIL-2) and tumor necrosis factor-alpha (TNF-alpha) were administered to Wistar rats in early stages of carcinogenesis. The results obtained suggest that IL-2 does not influence the development of nervous system tumors. In contrast, TNF-alpha was capable of modulating the development of ENU-induced tumors, producing a reduction in the number of schwannomas and a delay in the appearance of intraparenchymatous brain tumors.

Animals↗
PubMed1992

Expression of neuronal and glial markers in so-called oligodendroglial tumors induced by transplacental administration of ethyl-nitrosourea in the rat.

A series of 18 tumors with histological features of oligodendrogliomas, induced in the rat by means of transplacental ethyl-nitrosourea administration were studied for immunohistochemical demonstration of neuronal (synaptophysin and neurofilament protein) and glial (gliofibrillar acidic protein and vimentin) markers. Most of the tumors showed cells with strong positivity to synaptophysin and to a lesser degree, to neurofilament protein, suggesting the neuronal character of these neoplasms. In 10 tumors, cells with strong positivity to vimentin were found, and in three cases, tumoral cells expressed gliofibrillar acidic protein. The observation that ENU-induced oligodendroglial tumors express neuronal and, to a minor degree, glial markers, suggests their interpretation as primitive neuroectodermal tumors with clear neuronal differentiation.

Animals↗
PubMed1992

[Subclavian artery to internal carotid artery bypass with saphenous vein graft in the treatment of bilateral common carotid artery occlusion; a case report].

A case of left common carotid artery occlusion, which was treated by a saphenous vein graft, is reported. A 49-year-old right handed male was admitted to the hospital because of right hemiparesis and aphasia. These symptoms disappeared spontaneously two weeks after admission. However, visual acuity remained impaired on the left side due to occlusion of the central retinal artery. Angiography revealed complete occlusion of the common carotid arteries as well as patency of the internal carotid arteries on both sides. PET and 123I-IMP-SPECT studies showed hypoperfusion in the left cerebral hemisphere. To restore the blood flow as well as to remove the source of the emboli, endarterectomy was performed on the left internal carotid artery. This was followed by a saphenous vein graft between the left subclavian and the internal carotid artery. Postoperative angiography revealed patency of the bypass, and a SPECT study revealed increased blood flow in the left cerebral hemisphere. The patient has remained in stable condition during the following 30 months with no neurological problems. We conclude that in the treatment of complete occlusion of the common carotid artery and subsequent cerebral hypoperfusion, a bypass graft between the internal carotid and the subclavian artery is quite effective, and that the site of the bypass graft should carefully be sought for by using preoperative angiographic studies.

Anastomosis, Surgical↗
PubMed1991

Chromaffin allografts into arachnoid of spinal cord reduce basal pain responses in rats.

In this present study, behavioral responses to a subcutaneous formalin test for pain are evaluated in rats that previously received an allograft of adrenal chromaffin tissue into arachnoid of the dorsal spinal cord and in control animals. In the group of rats with grafts, a significant basal analgesia, reversed by the opioid antagonist naloxone, is found. These findings suggest that the grafts secrete some substance that reduces the response to painful stimulation and whose action is blocked by naloxone.

Adrenal Medulla↗
PubMed1991

A rapid intraoperative estimation of the proliferative activity in brain tumors.

A technique for staining the nucleolar organizer regions (NORs) in tumor cells applied to smears from brain tumor biopsy specimens is described. This technique provides a rapid intraoperative evaluation of the proliferative activity in cerebral neoplasms and is a valuable complement to hematoxylineosin stained smears, supporting the criteria of benignity or malignancy in these tumors.

Brain Neoplasms↗
PubMed1991

Natural killer cells in meningiomas.

A monoclonal antibody against the surface marker IOT-10 of natural killer (NK) cells was used to investigate the presence of these cells in a series of twenty intracranial meningiomas. In all of these tumours, IOT-10 positive NK cells were found in small numbers, mainly distributed among the tumor cells. Two recurrent tumors showed a relatively high number of immunostained cells. The data obtained in the present study suggest that a NK-cell-mediated immunological response can occur in meningioma tissue.

Adult↗
PubMed1990

Histological changes in glioblastoma after intratumoral injection of autologous lymphocytes and human lymphoblastoid interferon.

Seven glioblastomas were studied between 1 and 6 months after intratumoral injection of autologous lymphocytes and human lymphoblastoid interferon. Morphological study showed a great number of lymphocytes within the tumor tissue, and interactions between lymphocytes and glioblastoma cells, suggesting a killing phenomenon. These data support the potential usefulness of adoptive immunotherapy in patients with glioblastoma by means of intratumoral administration of activated lymphoid cells.

Brain Neoplasms↗
PubMed1990

Cerebral metastasis from angiosarcoma of the heart. Case report.

A case of secondary cerebral angiosarcoma in a 30-year-old man is presented. The patient had previously undergone heart transplantation for treatment of the primary tumor. Only a few cases of cerebral metastasis from angiosarcoma have been recorded in the literature; the present case is the first reported case diagnosed after heart transplantation.

Adult↗
PubMed1989

Intratumoural injection of autologous lymphocytes plus human lymphoblastoid interferon for the treatment of glioblastoma.

Preliminary experience with a clinical trial of immunotherapy for glioblastoma, by means of intratumoural injection of autologous lymphocytes (AL) mixed with low doses of human lymphoblastoid interferon (HLI) is presented. In two of twelve patients, a transient reduction of tumoural volume was obtained. Morphological studies showed that injected lymphocytes remain within the tumour, and suggest tumoural lysis due to activity of natural killer (NK) cells. Clinically no significant prolongation of survival time could be achieved and, as in other series, patients with additional radiation therapy survived longer. But the morphological findings suggest that immunotherapy carrying NK-cells to contact with tumoural cells might be useful in some patients with glioblastoma. Actually no explanation can be given why only two of our cases responded positively. Regarding the otherwise poor prognosis it seems justified to continue these studies.

Adult↗
PubMed1989

Presence and significance of NK cells in glioblastomas.

A monoclonal antibody against the surface marker IOT-10 of natural killer (NK) cells was used to investigate the presence of these cells in a series of 25 glioblastomas. In 40% of the tumors, IOT-10-positive NK cells were found in small numbers scattered among the tumor cells. The presence of IOT-10-positive NK cells was not related to the degree of lymphocytic infiltration in the tumor as demonstrated by hematoxylin and eosin staining, nor did it appear to influence the survival time of the patients studied.

Adult↗