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T Tohyama

Publications and source records attributed to T Tohyama.

48 records · Page 3Linked to original sources
PubMed1986

[Clinicopathological study of supratentorial tumors with multipotential differentiation in childhood. Primitive neuroectodermal tumor].

Three cases of supratentorial tumor in childhood were studied clinico-pathologically in an attempt to clarify its histological character. Case 1: A 3-year-old boy. Carotid angiogram revealed avascular lesion in the left parietal lobe. Twice operations and radiotherapy were performed. Ten months after the second operation, he died. Surgical specimen at the first operation was composed mainly of round tumor cells. The tumor tissue contained many collagen fibers. At the periphery of this tissue, medulloblastomatous areas consisting of closely aggregated hyperchromatic small round cells were found. There were perivascular rosettes and Homer Wright rosettes. In part, tubular and papillary arrangement of cells was also present. Astrocytomatous and oligodendrogliomatous structures were also present. Surgical specimens at the second operation showed the predominance of sarcomatous areas consisting of spindle-shaped cells with abundant argyrophilic fibers. Case 2: A 10-year-old girl. CT scan revealed a heterogeneous enhanced mass with a cyst and calcification in the right parietal lobe. Operation and radiotherapy were performed. Twelve months after operation, she is still alive. Most of the surgical specimens showed sarcomatous structure with abundant argyrophilic fibers. In these tissues, there were medulloblastomatous and ependymomatous features. Papillary arrangement of cells was also present. In part, there was oligodendrogliomatous structure. Case 3: A 2-year-old girl. CT scan revealed a heterogeneous enhanced mass in the right frontal lobe. The tumor tissue was composed of an aggregation of undifferentiated small round cells with Homer Wright rosettes.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Neoplasms↗
PubMed1986

[Treatment of malignant brain tumors with slowly releasing anticancer drug-polymer composites].

The purpose of this study is to present the methodology and results of a clinical trial of local chemotherapy of malignant brain tumors based on slowly-releasing anticancer drug-polymer composites. The slowly releasing drugs were prepared by combining and mutually dispersing anticancer agents with glassified monomers containing 10% polymetacrylic methyl acid and then this compound was frozen at -78 degrees C and exposed to 1 X 10(6) rad of gamma rays from cobalt 60. Thus we prepared a compound of polymers and anticancer agents. We used needle-shaped capsules of this compound. These capsules release the drug very slowly over 40 days. We administered locally to the malignant brain tumors with either slowly releasing mitomycin, slowly releasing adriamycin, slowly releasing ACNU or slowly releasing 5 Fu drugs. The following techniques were employed in implantation these capsules. Implantation into the remaining tumor wall at the time of excision. Implantation into the tumor by CT-guided stereotactic method. We implanted these drugs into tumor of 55 cases, thereafter we conducted both radiation and chemotherapy with ACNU in most patients. This method has the following advantages: It is possible to be employed to different types of anticancer agents. Both dosage and releasing time can be adjusted. It is possible to administer these capsules postoperatively by the stereotactic method. The clinical study consists of 55 patients, 20 cases of anaplastic astrocytoma, 23 cases of glioblastoma multiforme, 5 cases of oligodendroglioma, 3 cases of medulloblastoma and 4 cases of others. Survival rate estimated by Kaplan-Meier method was 47% in glioblastoma at 12 months and 91% in anaplastic astrocytoma at 18 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1975

Pseudocyst of the pericardium developing during maintenance hemodialysis. Report of two cases.

Two cases of pericardial pseudocyst which developed in the course of maintenance hemodialysis are reported. Both patients were usually free of complaints, although there was evidence of the previous pericarditis with recent accumulation of pericardial effusion. As a possible mechanism leading to pericardial pseudocyst formation, distension of a weak area of the thickened pericardium due to an increase in intrapericardial pressure was assumed. Therefore, pericardial pseudocyst is one of the likely complications of patients on maintenance hemodialysis.

Adult↗
PubMed1975

[Clinical value of magnification cerebral angiography (author's transl)].

Magnification carotid and vertebral angiography was performed via femoral catheter with magnification factor of 2.5 to 3.0, utilizing 0.1 X 0.1 ultra fine focal spot, manufactured by Shimadzu Seisakusho, Ltd. The standard angiograms were compared with magnification angiograms in a group of 67 patients with brain tumors and vascular disorders. The magnification angiography was more valuable than conventional angiography in 12 of 17 vascular tumors, while it was rarely valuable for diagnosis of vascular tumors. Aneurysms, occlusive diseases, collateral vessels, and capillary blush were also visualized to better advantage on magnification angiograms. Magnification cerebral angiography is a useful tool for elucidating small vascular branches, but further refinement in the design of focal spots and angiographic techinques is required for further improvement of magnification cerebral angiography.

Adenocarcinoma↗
PubMedDate not supplied

In vivo and in vitro models of medulloblastomas and other primitive neuroectodermal brain tumors of childhood.

Recent advances in understanding the basic biology of the neoplastic cells that populate childhood primitive neuroectodermal tumors (PNET) of the central nervous system (CNS) underline several unique properties of these common pediatric brain neoplasms. For example, studies of posterior fossa cerebellar medulloblastomas (MB), a prototypical group of brain tumors that comprise the largest class of PNET, suggest that the molecular phenotype of subpopulations of neoplastic cells in MB partially recapitulates stages in the acquisition of the neuronal phenotype by normal developing human CNS progenitor cells. However, as reviewed here, it appears that the neoplastic cells in MB exhibit one or more molecular defects in the sequence of normal maturational events that enable CNS progenitor cells to exit the cell cycle, become committed to the neuronal lineage, and undergo terminal differentiation into fully mature, permanently postmitotic CNS neurons. Indeed, since PNET emerge almost exclusively in early childhood, the induction of PNET may result from genetic lesions that arise in developing CNS progenitor cells thereby preventing these neural precursors from executing normal programs of lineage commitment and differentiation in the CNS. Clarification of how lineage commitment and maturation in PNET comprised of neuron-like tumor cells deviate from normal CNS development may clarify how oncogenes and tumor suppressor genes exert their effects in a cell type specific manner at different stages in the normal maturation of CNS cells. Recently, a number of potentially effective in vitro and in vivo model systems of PNET have been developed. Since these model systems could facilitate efforts to elucidate mechanisms of neoplastic transformation and tumor progression in the CNS, we review the potential utility of several recently described in vitro (e.g., MB cell lines) and in vivo (e.g., transgenic mice) experimental systems as models of authentic childhood CNS neoplasms.

Animals↗