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N Arita

Publications and source records attributed to N Arita.

At least 163 records · Page 9Linked to original sources
PubMed1983

[Effect of dexamethasone on tumorous brain edema--changes in regional cerebral blood flow and glucose utilization].

An experimental brain tumor was produced by implanting a piece of A.A. ascites tumor into the parietal brain of rat. Local cerebral blood flow (LCBF) and glucose utilization (LCGU) were determined in this model with 14C-iodoantipyrine and 14C-deoxyglucose quantitative autoradiographic methods, respectively, to investigate the change of blood flow and glucose metabolism and the effect of dexamethasone in the brain with tumor. LCBF and LCGU in the peritumoral brain tissue were reduced 75% and 60%, respectively, compared with the values of the control. In the ipsilateral frontal and occipital cortical areas far from the tumor, 50% and 45% reduction of LCBF, respectively, was observed. More than 30% reduction of LCGU was seen in the same areas. In the caudate and corpus callosum ipsilateral to the tumor, LCBF was diminished 25% and 40%, respectively. LCGU was not significantly changed in these areas. No significant changes of LCBF and LCGU were observed in the contralateral hemisphere. In the dexamethasone-treated animal, the reduction of LCBF was less in all areas where it was reduced in the untreated animal. In the peritumoral brain tissue, LCBF was significantly higher compared to that of the untreated group, and 80% of the normal level. In the ipsilateral frontal and occipital cortical areas, caudate and corpus callosum, LCBF was about the same as that of the control group. In the animal treated with dexamethasone, quantitative analysis of LCGU could not be made because of high glucose levels in plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Distribution of bleomycin in ethylnitrosourea-induced gliomas in rats.

We used a microbioassay to study the distribution of bleomycin in rat brain tumors induced in newborn Sprague-Dawley rats with 1-ethyl-1-nitrosourea (ENU, 50 mg/kg s.c.). Upon suspected successful tumor induction bleomycin (0.1 g/kg i.v.) was administered, and 2 hr later bleomycin concentrations in major organs and tumor tissues were bioassayed using Bacillus subtilis PCI 219 IMC. To determine their histology, the tumors were stained by the immunofluorescence- or immunoperoxidase method using antiserum to astroprotein in addition to the conventional staining methods. There were 11 gliomas each of the brain and spinal cord, 14 schwannomas of the trigeminal nerve and 4 adenomas of the pituitary gland; they developed within 8 (gliomas), 7.3 (schwannomas) and 15 (adenomas) months on average after ENU treatment. The bleomycin concentration and the tumor:plasma concentration ratio were 7.69 +/- 2.84 micrograms/g and 0.13 +/- 0.05 (brain gliomas), 7.10 +/- 3.15 micrograms/g and 0.27 +/- 0.12 (spinal cord gliomas), 5.40 +/- 1.41 micrograms/g and 0.23 +/- 0.05 (schwannomas), 4.83 +/- 1.05 micrograms/g and 0.21 +/- 0.08 (adenomas). Normal brain- and spinal cord tissues scarcely contained bleomycin.

Animals↗
PubMed1981

Alteration of blood-CSF barrier by tumor invasion into the meninges.

Cyclophosphamide and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) were found to have an equivalent cytostatic effect in rats with subcutaneous transplants of Walker 256 carcinosarcoma. Rats with meningeal carcinomatosis received a single intravenous dose of cyclophosphamide (30 mg/kg) or ACNU (15 mg/kg) at various times after intracisternal inoculation of 1 X 10(4) Walker 256 carcinosarcoma cells. Cyclophosphamide, administered 1 day after tumor inoculation, failed to prevent tumor growth in the subarachnoid space. The survival time of these rats was prolonged only 10% to 14% compared to the controls, while ACNU produced a maximum increased survival time of 180%. If administered 2, 3, 4, and 5 days after tumor inoculation, both drugs were effective; cyclophosphamide yielded a maximum increase in median survival time of 109%, 94%, 90%, and 52%, and ACNU 127%, 139%, 240%, and 100%, respectively. These results indicate that the blood-cerebrospinal fluid (CSF) barrier was circumvented in the early stage of subarachnoid tumor growth, although some areas remained where the infiltrating tumor cells were protected from systemically administered drugs by the intact barrier.

Animals↗
PubMed1981

Regional blood flow and capillary permeability in the ethylnitrosourea-induced rat glioma.

Regional cerebral blood flow and capillary permeability of rat brains bearing ethylnitrosourea-induced gliomas of various size were investigated with 14C-antipyrine autoradiography and Evans blue staining. In the small tumors (less than 2 mm in diameter), blood flow was uniformly reduced when compared to the adjacent brain. Even in tiny tumors (0.3 to 0.4 mm in diameter), reduction in blood flow was evident. In the medium (2 to 4 mm in diameter) and large (greater than 4 mm in diameter) tumors, the blood flow increased or decreased depending on the part of the tumor examined. The necrotic center and peripheral edge had low blood flows, whereas the viable portion adjacent to the necrotic center had high blood flows. Blood flow in the brain tissue adjacent to medium and large tumors was lower than control brain tissue, probably due to local edema. Leakage of intravenous Evans blue in the tissue was only evident in the large tumors with central necrosis. The present findings suggest that neovascularization of the tumor may occur when the tumor reaches a certain size, and leaky new vessels may be the cause of brain edema associated with tumor.

Animals↗
PubMed1981

[Regional blood flow in the ethylnitrosourea induced rat glioma (author's transl)].

Regional cerebral blood flow of rat brains bearing ethylnitrosourea induced glioma of various size was investigated with 14C-antipyrine autoradiography. In the small tumors (less than 2 mm in diameter), blood flow was uniformly reduced when compared to the adjacent brain. Even in tiny tumors (0.3-0.4 mm in diameter), reduction in blood flow was evident. In the medium (2-4 mm in diameter) and large (greater than 4 mm in diameter) tumors, the blood flow increased in the viable center of the tumor and decreased in the necrosis and peripheral edge. High blood flow in the viable center may be attributable to the neovascularization of the tumor. Blood flow in the brain tissue adjacent to medium and large tumors was lower than control brain tissue probably due to local edema. This reduction in blood flow may be partly attributable to the appearances of the focal neurologic deficits. The result obtained may provide some information about growth regulation of glioma and also pharmacokinetic delivery of chemotherapeutic drugs to the malignant brain tumors.

Animals↗
PubMed1980

Primary pineal endodermal sinus tumor with elevated serum and CSF alphafetoprotein levels. Case report.

A 12-year-old girl with an alphafetoprotein-producing brain tumor in the pineal region is presented. The marker was detected in both serum and cerebrospinal fluid. The amount of the marker decreased after irradiation of the tumor and systemic chemotherapy and increased prior to tumor recurrence. At autopsy, the tumor was histopathologically diagnosed as an endodermal sinus tumor, and alphafetoprotein was demonstrated in the tumor cells by the immunofluorescence method. Alphafetoprotein may represent a specific and sensitive marker for predicting tumor histopathology and for monitoring the therapeutic response in patients with primary intracranial germ-cell tumors.

Brain Neoplasms↗
PubMed1980

Serum levels of alpha-fetoprotein, human chorionic gonadotropin and carcinoembryonic antigen in patients with primary intracranial germ cell tumors.

Serum levels of alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG) and carcinoembryonic antigen (CEA) were determined by radioimmunoassay in 14 patients with primary intracranial germ cell tumors in the pineal and/or chiasmal region and the relationship between AFP, HCG and CEA levels, tumor histopathology and survival time was studied. In 7 of the 14 patients, elevation of AFP and/or HCG was noted. Histopathological diagnosis of these patients was embryonal carcinoma (1), choriocarcinomas (2) and seminoma (4). Five of the 7 patients died within 2 years after diagnosis in spite of surgery and/or radiation therapy. Seven patients who showed normal AFP and HCG levels consisted of 6 germinomas and one teratoma. Four of the 7 patients remain alive and well more than 5 years after surgery and/or radiation therapy. CEA was above normal in only one patient with a seminoma. Our results suggest that the serum levels of AFP and HCG are useful for predicting tumor histopathology and the prognosis of patients with primary intracranial germ cell tumors.

Adolescent↗
PubMed1980

Dural arteriovenous malformation near the left sphenoparietal sinus.

The case of a 14-year-old boy with a dural arteriovenous malformation in the region of the sphenoparietal sinus associated with a markedly dilated dural sinus is reported. The arterial supply was solely via the meningeal branches of the left external carotid artery; venous drainage was through dilated venous channels into the superior ophthalmic vein and pterygoid venous plexus. Treatment consisted of artificial embolization and ligation of the left external carotid artery and excision of the dilated venous sac. The vascular lesions were absent from the post-operative angiogram, except for small angiomatous remnants fed by meningeal branches of the left internal carotid artery.

Adolescent↗
PubMed1980

Primary fibrosarcoma of the skull.

The case of a 61-year-old woman with fibrosarcoma of the skull is discussed. Despite surgical treatment and irradiation, she died 23 months after diagnosis. Primary fibrosarcoma of the skull is rare but must be considered in the differentiation of the osteolytic lesions of the skull.

Female↗