Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Kouichi Wada is active.

Publication


Featured researches published by Kouichi Wada.


Brain Tumor Pathology | 2004

Genetic analysis of human glioblastomas using a genomic microarray system.

Tsuyoshi Suzuki; Motohiko Maruno; Kouichi Wada; Naoki Kagawa; Yasunori Fujimoto; Naoya Hashimoto; Shuichi Izumoto; Toshiki Yoshimine

Genomic microarray systems can simultaneously provide substantial genetic and chromosomal information in a relatively short time. We have analyzed genomic DNA from frozen sections of 30 cases of primary glioblastomas by GenoSensor Array 300 in order to characterize gene amplifications, gene deletions, and chromosomal information in the whole genome. Genes that were frequently amplified includedPFC2/CYLN2 (63.3%),EGFR (53.3%),IL6 (53.3%),ABCB1 (MDR1) (36.7%), andPDGFRA (26.7%). Genes that were frequently deleted includedFGFR2 (66.7%),MTAP (60.0%),DMBT1 (56.7%),CDKN2A (p16)/MTAP (50.0%),PIK3CA (43.3%), andEGR2 (43.3%), but deletion ofRB1 orTP53 was rarely detected. Chromosomal gains were observed frequently for 7q (33.3%), 7p (20.0%), and 17q (13.3%). Loss of the 10q was frequently detected in 13 of 30 cases (46.7%). Loss of the entire chromosome 10 was seen in 9 of 30 cases (30.0%), and was often accompanied byEGFR amplification (7 cases, 77.8%). The GenoSensor Array 300 proved to be useful for identification of genome-wide molecular changes in glioblastomas. The obtained microarray profile can also yield valuable insight into the molecular events underlying carcinogenesis of brain tumors and may provide clues about clinical correlations, including response to treatment.


Journal of Neuro-oncology | 2005

Ganglioside GM3 inhibits proliferation and invasion of glioma

Yasunori Fujimoto; Shuichi Izumoto; Tsuyoshi Suzuki; Manabu Kinoshita; Naoki Kagawa; Kouichi Wada; Naoya Hashimoto; Motohiko Maruno; Yuji Nakatsuji; Toshiki Yoshimine

GM3, the simplest ganglioside, modulates cell adhesion, proliferation and differentiation in the central nervous system and exogenously added GM3 regulates cell–cell and cell–extracellular matrix adhesion and induces apoptosis. To assess the anti-tumor action of exogenous GM3, we examined its effect on the proliferation and invasion of glioma cells. Its inhibitory effect on cell proliferation was demonstrated in vitro by 3-(4,5-dimethyl-2-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and in vitro in rats with meningeal gliomatosis whose survival was significantly prolonged by the intrathecal injection of GM3. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay revealed that GM3 induced glioma cell apoptosis in vitro and in vitro. In rat brain slice cultures, GM3 suppressed the invasion of glioma cells; this effect manifested earlier than the inhibition of cell proliferation and before apoptosis induction. Our results suggest exogenous GM3 as a potential therapeutic agent in patients with glioma requiring adjuvant therapy.


Journal of Neuro-oncology | 2005

Inhibition of glioma cell proliferation by neural stem cell factor

Tsuyoshi Suzuki; Shuichi Izumoto; Kouichi Wada; Yasunori Fujimoto; Motohiko Maruno; Mami Yamasaki; Yonehiro Kanemura; Takuya Shimazaki; Hideyuki Okano; Toshiki Yoshimine

SummaryNeural stem cells (NSC) have unique differentiation-, proliferation-, and motility properties. To investigate whether they secrete factors that interfere with the proliferation of glioma cells, we grew glioma cells in conditioned medium (CM) obtained from cultures of neurospheres including neural stem / progenitor cells (NSPC) isolated from embryonic (E14)- or adult mouse brain or fetal human brain. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and BrdU-labeling assays showed that CM from NSPC (NSPC/CM) contained factor(s) that inhibited the proliferation of glioma cells by 28–87%. Filter-fractionation of NSPC/CM revealed that the 50,000–100,000 nominal molecular weight limit (NMWL) fraction contained the inhibitory activity. On the basis of these observations we transplanted 203G glioma cells and/or NSPC into the intrathecal space of the cisterna magna of mice to investigate whether NSPC interfere with the proliferation of glioma cells in vivo. Mice transplanted with both 203G and NSPC survived significantly longer than did mice transplanted only with 203G. We concluded that NSPC secrete factor(s) that may control glioma cell proliferation.


Brain Tumor Pathology | 2004

Chromosomal and genetic aberrations differ with meningioma subtype.

Kouichi Wada; Motohiko Maruno; Tsuyoshi Suzuki; Naoki Kagawa; Tetsuo Hashiba; Yasunori Fujimoto; Naoya Hashimoto; Shuichi Izumoto; Toshiki Yoshimine

Meningioma is one of the most common brain tumors, and a variety of genetic abnormalities have been detected by the Southern blotting, polymerase chain reaction (PCR), fluorescence in situ hybridization (FISH), and comparative genomic hybridization (CGH) methods. However, these methods detect only a very limited portion of the tumor genome or have a limited mapping resolution. In this study, we used DNA microarray assay, which detects numerous genetic abnormalities and analyzes a global assessment of molecular events in tumor cells. We analyzed genomic DNA from 26 patients with benign meningiomas by GenoSensor Array 300 in order to characterize gene amplifications, gene deletions, and chromosomal information in the whole genome. Loss of chromosome 22q was found most frequently. This chromosomal aberration was detected in 14 meningiomas (53.8%), particularly in transitional and fibrous meningiomas. In meningothelial meningiomas, amplification ofINS andTCL1A was detected more frequently than in other meningioma subtypes. DNA microarray assay revealed new genetic differences among the meningioma subtypes, thus indicating that this novel technique is useful for understanding tumor genesis and for the diagnosis of meningioma subtype.


Brain Tumor Pathology | 2006

Skull metastasis from papillary thyroid carcinoma accompanied by neurofibromatosis type 1 and pheochromocytoma: report of a case.

Tetsuo Hashiba; Motohiko Maruno; Yasunori Fujimoto; Tsuyoshi Suzuki; Kouichi Wada; Toshihiko Isaka; Shuichi Izumoto; Toshiki Yoshimine

We report here a 74-year-old woman with a skull metastasis from papillary thyroid carcinoma (PTC). In her medical history, she was diagnosed with neurofibromatosis type 1 (NF1) at age 28 years, and she underwent thyroidectomy for PTC at age 52 years and adrenectomy for pheochromocytoma (PC) at age 58 years. She was admitted to our hospital with an increased mass in the forehead. Head computed tomography (CT) showed an expansive, osteolytic, and solid tumor extending from the dura mater into the subcutis, destroying part of the frontal bone. Head magnetic resonance imaging (MRI) revealed that the tumor was chiefly extradural but partially invaded the dura mater. Cerebral angiography showed that the tumor was fed from a branch of the external carotid artery. She underwent surgery, and histological examination revealed that the skull tumor was a metastasis from PTC, indicating that skull metastasis occurred 23 years after curative surgery for PTC. The patient also underwent adjuvant radioiodine therapy. As little is known about skull metastases from PTC, we discuss its characteristics and the extremely rare combined occurrence of PC and PTC in an NF1 patient.


Neurological Research | 2005

Chromosomal and genetic abnormalities in benign and malignant meningiomas using DNA microarray

Kouichi Wada; Motohiko Maruno; Tsuyoshi Suzuki; Naoki Kagawa; Tetsuo Hashiba; Yasunori Fujimoto; Naoya Hashimoto; Shuichi Izumoto; Toshiki Yoshimine

Abstract Background: Meningioma is the commonest brain tumor and many genetic abnormalities, such as the loss of chromosome 22q and the mutation of NF2, have been reported. Methods: These classical abnormalities were detected using Southern blot, PCR, fluorescence in situ hybridization and comparative genomic hybridization, but these methods examine only very limited regions or limited mapping resolution of the tumor genome. In this study, we used DNA microarray assay, which detects numerous genetic abnormalities simultaneously and analyses a global assessment of molecular events in meningioma cells. We studied 31 meningiomas by GenoSensor Array 300 in order to detect the chromosomal aberrations and genetic abnormalities in the whole genome. Results: This study demonstrated not only classical chromosomal aberration, such as loss of chromosome 22q in 19 meningiomas (61.3%), but also new genetic characteristics of meningiomas, such as amplification of MSH2 in 16 meningiomas (51.6%), deletion of GSCL in 13 meningiomas (41.9%) and deletion of HIRA in seven meningiomas (22.6%). Conclusions: These results suggest that DNA microarray assay is useful in research for the genetic characters of meningiomas and understanding tumorigenesis.


Brain Tumor Pathology | 2006

Giant cell type of primary intracranial malignant fibrous histiocytoma: a case report.

Motohiko Maruno; A. K. M. Ghulam Muhammad; Junji Taguchi; Tsuyoshi Suzuki; Kouichi Wada; Toshihiko Isaka; Toshiki Yoshimine

The primary intracranial giant cell type of malignant fibrous histiocytoma (GC-MFH) is rare, and the resemblance to meningioma causes diagnostic confusion. Discrimination from meningioma bears important therapeutic and prognostic implications. We report one such case in which an extracranial malignant neoplasm was seen after the initial diagnosis and treatment. A 62-year-old woman presented with history of seizure. MRI revealed a huge right frontotemporal, homogeneously enhanced extraaxial lesion with significant mass effect. The main vascular supply was the middle meningeal artery. Workup for lesions elsewhere was negative. Gross total resection including dural attachment was achieved. The histopathological features were consistent with the diagnosis of GC-MFH. Immunohistochemistry disclosed varied reactivity profiles in tumor component cells: the spindle-shaped cells possessed features of mesenchymal and hematopoietic lineage, the histiocytic cells those of mesenchymal and epithelial cells, and the osteoclast-like multinucleated giant cells those of monocyte/macrophage and epithelial cells. Proliferative activity was absent in giant cells. Local irradiation of 60 Gy (linac) was performed. The patient did well for 10 months, and follow-up MRI showed no evidence of tumor recurrence. Subsequently, she developed ascites and died 3 months later as a consequence of end-stage adenocarcinoma (ovary) with peritoneal dissemination. There is no established treatment protocol for primary intracranial MFH. Although gross total resection and local irradiation were effective in the short-term control of local relapse in the present case, occurrence of extracranial neoplasm was fatal. Close follow-up aimed at early detection of local recurrence and distant metastases, as well as extracranial malignancy, remains important.


Neurosurgical Review | 2001

Intraoperative ultrasonographically guided direct ethanol injection for a brain metastasis from renal cell carcinoma: case report

Toshihiko Isaka; Hidemitsu Nakagawa; Junji Yamada; Tsuyoshi Suzuki; Kouichi Wada

Abstract A 60-year-old man presented with a brain metastasis from renal cell carcinoma (RCC). Computer tomography revealed a homogeneously enhanced tumor, 3.0 cm in maximum diameter, in the right medial temporal lobe. Cerebral angiography revealed that the tumor was mainly fed by the right posterior cerebral artery. Surgery was performed via right temporal craniotomy. After craniotomy, under ultrasonography (US) guidance, a total of 3.0 ml of ethanol was injected into the tumor to diminish the intratumoral vascular flow. Ultrasonographic guidance was very useful in monitoring the intratumoral vascular flow. After a marked decrease in the vascular flow, the tumor was totally removed using piecemeal technique. During surgery, only minimal bleeding from the tumor was noted. The postoperative course was uneventful, with no evidence of injected ethanol-related complications. In conclusion, this can be a safe, easy, and effective therapeutic technique for diminishing vascular flow within brain tumors rich in vascularity, such as brain metastases from RCC.


Proceedings of the 14th IBM Computer SCience Symposium on Operating Systems Engineering | 1980

Specification of schedulers with algebraic specification techniques

Kouichi Wada; Kenichi Hagihara; Toshiro Araki; Nobuki Tokura

The specification of a class of single resource schedulers is presented. A class of these schedulers is regarded as a parameterized data type whose formal parameter is a scheduling strategy. The specification is given by using the concept of parameterization in algebraic techniques. The specification of each scheduler instance can be directly obtained only by replacing the formal parameter with a concrete scheduling strategy. The assignment of an actual parameter to a formal parameter is given by a mechanism called extended parameter morphisms. This specification technique is applicable to many other objects.


Surgical Neurology | 2005

Immunohistochemical detection of female sex hormone receptors in craniopharyngiomas: correlation with clinical and histologic features

Shuichi Izumoto; Tsuyosi Suzuki; Manabu Kinoshita; Tetsuo Hashiba; Naoki Kagawa; Kouichi Wada; Yasunori Fujimoto; Naoya Hashimoto; Youichi Saitoh; Motohiko Maruno; Toshiki Yoshimine

Collaboration


Dive into the Kouichi Wada's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Naoya Hashimoto

Kyoto Prefectural University of Medicine

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge