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Norio Arita

Publications and source records attributed to Norio Arita.

9 recordsLinked to original sources
PubMed2006

Short-term preoperative octreotide treatment of GH-secreting pituitary adenoma: predictors of tumor shrinkage.

We reviewed the cases of 32 patients with growth hormone (GH)-secreting macroadenoma who underwent short-term octreotide treatment before transsphenoidal surgery to determine which types of adenoma the preoperative treatment were sensitive and whether predictors of tumor shrinkage could be identified. The effects of preoperative octreotide treatment, endocrinologic effect and effect on tumor volume in 32 patients were evaluated retrospectively in relation to tumor features on magnetic resonance images and responses to endocrinologic challenge tests. At a daily dose of 300 microg for 2-3 weeks, octreotide reduced serum GH and insulin-like growth factor-1 (IGF-1) levels to 31.9 % and 51.6% of pretreatment values, respectively, and led to a mean tumor volume of 68% of pretreatment volume in 52% of the patients. The endocrinologic effect and the effect on tumor volume were larger in Knosp grades 0-2 than in Knosp grades 3-4. Tumor shrinkage occurred significantly more often among patients that had a good response to both octreotide and bromocriptine challenge tests. For surgical removal of the tumor, the effect of reducing tumor to 68% of pretreatment volume will be beneficial for the macroadenomas of Knosp grades 1-2. Preoperative short-term octreotide treatment is effective for GH-secreting macroadeomas of Knosp grades 1-2 and a good response to both octreotide and bromocriptine challenge tests is a predictor of subsequent tumor shrinkage. These results will lead to more effective selection of patients for preoperative octreotide treatment.

Acromegaly↗
PubMed2005

[Meningioma].

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed2004

[Usefulness of Cho/Cr ratio in proton MR spectroscopy for differentiating residual/recurrent glioma from non-neoplastic lesions].

PURPOSE: We evaluated the clinical usefulness of the Cho/Cr ratio of proton MR spectroscopy(1H-MRS) to differentiate residual/recurrent glioma from non-neoplastic lesions. PATIENTS AND METHODS: 20 cases of glioma were involved in this study(astrocytoma grade I-II: 7, oligodendroglioma: 1, astrocytoma grade III: 2, glioblastoma: 10). Seven of the patients underwent surgical resection only, 4 underwent surgical resection and radiotherapy(40-60 Gy), and 9 underwent surgical resection and radiotherapy with concurrent chemotherapy(14-60 Gy). 1H-MRS was performed on a 1.5 Tesla clinical MR unit using a 3D-chemical shift imaging sequence(1500 msec/270 msec/1 (TR/TE/excitations), and the Cho/Cr ratio was calculated in the voxel where neoplastic lesion was most suspected on MRI. The presence of lactate + lipid peak was also evaluated. All spectra were obtained after the contrast enhanced study. RESULTS: Cho/Cr ratios were significantly higher in cases of residual/recurrent tumors(mean +/- SD = 1.70 +/- 0.96) than in non-neoplastic lesions(mean +/- SD = 1.04 +/- 1.16) (Mann-Whitney U-test p = 0.047). If a Cho/Cr ratio of more than 1.5 was used as a marker of tumor presence, its sensitivity was 64%, specificity 83%, and accuracy 70%. One false-positive case that of radiation necrosis whose spectrum showed a high Cho/Cr ratio with markedly elevated lactate + lipid peak. CONCLUSION: The Cho/Cr ratio of 1H-MRS provides additional information to MRI in differentiating residual/recurrent gliomas from non-neoplastic lesions.

Adolescent↗
PubMed2002

Central neurocytoma with craniospinal dissemination.

We report a case of central neurocytoma that manifested tumor recurrence with craniospinal dissemination. Imaging studies before surgery showed a markedly enhanced tumor with small cysts and calcification, which invaded the adjacent brain parenchyma, located in the posterior horn of the right lateral ventricle. Proton MR spectroscopy showed markedly elevated choline and lactate peaks with a strongly diminished N-acetylaspartate peak. Two years after neurosurgical intervention, the tumor showed multiple craniospinal dissemination in the middle cranial fossa and the intradural extramedullary space of the spine.

Adult↗
PubMed2002

Evaluation of in vitro proliferative activity of human fetal neural stem/progenitor cells using indirect measurements of viable cells based on cellular metabolic activity.

To scale up human neural stem/progenitor cell (NSPC) cultures for clinical use, we need to know how long these cells can live ex vivo without losing their ability to proliferate and differentiate; thus, a convenient method is needed to estimate the proliferative activity of human NSPCs grown in neurosphere cultures, as direct cell counting is laborious and potentially inaccurate. Here, we isolated NSPCs from human fetal forebrain and prepared neurosphere cultures. We determined the number of viable cells and estimated their proliferative activity in long-term culture using two methods that measure viable cell numbers indirectly, based on their metabolic activity: the WST-8 assay, in which a formazan dye is produced upon reduction of the water-soluble tetrazolium salt WST-8 by dehydrogenase activity, and the ATP assay, which measures the ATP content of the total cell plasma. We compared the results of these assays with the proliferative activity estimated by DNA synthesis using the 5-bromo-2'-deoxyuridine incorporation assay. We found the numbers of viable human NSPCs to be directly proportional to the metabolic reaction products obtained in the WST-8 and ATP assays. Both methods yielded identical cell growth curves, showing an exponentially proliferative phase and a change in the population doubling time in long-term culture. They also showed that human NSPCs could be expanded for up to 200 days ex vivo without losing their ability to proliferate and differentiate. Our findings indicated that indirect measurements of viable cells based on metabolic activity, especially the ATP assay, are very effective and reproducible ways to determine the numbers of viable human NSPCs in intact neurospheres.

Adenosine Triphosphate↗
PubMed2002

Brain-specific angiogenesis inhibitor 1 (BAI1) is expressed in human cerebral neuronal cells.

Brain-specific angiogenesis inhibitor 1 (BAI1) is a p53-target gene specifically expressed in the brain. We examined the distribution of the endogenous BAI1 protein in normal human brain tissue using a polyclonal antibody against the extracellular region of BAI1. Immunohistochemical study demonstrated that BAI1 was expressed in neuronal cells of the cerebral cortex but not in astrocytes. BAI1 protein was localized in the cellular cytoplasm and membrane. It was predominantly localized in the cellular membrane when expressed in cultured cells by means of gene transfection. BAI1 protein may play an important role in neuronal functions such as synapse formation and signal transduction.

Adult↗
PubMed1998

Neural Cell Adhesion Molecule L1 Promotes Regeneration of Injured Optic Nerve of Rats.

Neural cell adhesion molecule L1 is a member of the immunoglobulin superfamily; it plays an important role in neurite outgrowth in vitro. We present evidence that the transected optic nerve in adult rats was promoted to regenerate by transplanted L1-expressing cells that were embedded in the Matrigel matrix. To obtain the maximum effects, a very careful operative procedure by which both stumps remained attached and the blood supply was preserved was essential. Visual evoked potential was partially recovered and traced fibers were seen to pass through the lesion site 7 weeks after optic nerve transection. Immunohistochemical analysis demonstrated that neurofilament-positive fibers were present around the site of experimental lesion. Our in vivo study demonstrated that L1 promoted the regeneration of the lesioned optic nerve in rats under strictly controlled environmental conditions.

Journal Article↗