Biomedical subjects

Michiyasu Suzuki

Publications and source records attributed to Michiyasu Suzuki.

48 records · Page 3Linked to original sources

PubMed2002

Chromosome instability in malignant astrocytic tumors detected by fluorescence in situ hybridization.

Malignant tumors intrinsically manifest genetic instability, and consequently genetic aberrations successively accumulate in tumor cells as the tumor progresses. However, the relationship of genetic instability and biological behavior still remains to be investigated in malignant tumors. In the present investigation, the relationship between chromosomal instability and patient prognosis was studied in 19 malignant gliomas. Chromosomal instability was estimated by numerical variation in chromosomes 7, 10 and 17 which was measured by fluorescence in situ hybridization (FISH), and DNA ploidy was determined by laser scanning cytometry. The mean number of fractions was significantly higher in cases with DNA aneuploidy than in those with DNA diploidy. The tendency toward higher fractions in glioblastomas existed, although it did not reach statistical significance. Kaplan-Meier survival rate analysis demonstrated significantly lower survival rates in patients with higher fractions of chromosome 7 (>5) than others. Our results suggest that DNA aneuploidy in malignant gliomas reflects an underlying chromosomal instability, and that this instability is associated with clinical behavior.

Adult↗

PubMed2002

Adenovirus-mediated gene transfer of B7.1 induces immunological anti-tumor effects in a murine brain tumor.

The purpose of the present study was to determine if adenovirus-mediated transfection of a syngeneic mouse brain tumor with the gene encoding B7.1 enhances immunogenicity against tumor. Malignant astrocytoma cells were transfected with adenoviral vectors carrying the B7.1 gene (AdB7). Immunocytochemical analysis confirmed the expression of B7.1 in vitro and in vivo. To investigate the effects of B7.1 expression on tumorigenicity of the malignant astrocytoma, mice were implanted intracerebrally with B7.1-transfected glioma cells. There was no significant difference in proliferation between B7.1-transfected cells and controls in vitro. Nevertheless, mice implanted with B7. 1-transfected cells survived significantly longer than those in the control groups. Immunocytochemical analysis of the tumors showed that there was infiltration of a number of CD8+ T-cells and CD25+ activated T-cells in the brain implanted with B7.1-transfected glioma cells. The results showed the possibility that adenovirus-mediated B7.1 gene transfection to a brain tumor induced activation of CD8+ cytotoxic T-lymphocytes.

Adenoviridae↗

PubMed2002

Recurrent intracranial germinoma with dissemination along the ventricular catheter: a case report.

Most recurrences of intracranial pure germinoma occur at the primary site, ventricular wall or subarachnoid space. We report a rare case of intracranial germinoma that recurred along the shunt tube 17 years after prior ventriculoperitoneal shunt and radiotherapy. The recurrent tumor, verified histologically as a pure germinoma, involved the right frontal lobe along the ventricular catheter. In spite of subsequent surgery, radiation and chemotherapy, the tumor recurred repeatedly. Recurrence after such a long period highlights the necessity of long-term follow up for patients with germinoma. We also discuss possible causes of tumor dissemination along the ventricular catheter.

Adult↗

PubMed2002

Amino acid concentrations in the blood of the jugular vein and peripheral artery after traumatic brain injury: decreased release of glutamate into the jugular vein in the early phase.

The gross behavior of excitatory amino acids in patients with traumatic brain injury (TBI), including uptake, transport, metabolism, and clearance, was investigated by analysis of the levels of 41 amino acids in the blood of the jugular vein (JV), which is the primary venous drainage conduit of the brain, and a peripheral artery. Blood samples from the JV and a peripheral artery of eight patients with TBI were collected at 6 h, 6 to 24 h, and over 24 h after TBI, and analyzed using high performance liquid chromatography. Blood samples from 101 normal subjects were also measured. The levels of glutamate (Glu), gamma-aminobutyric acid (GABA), aspartate, glutamine, and cystine deviated from the normal range, and were considered pathological. The level of Glu in the JV was significantly lower than that in the artery (p < 0.05), and the level of GABA in the JV was significantly higher than that in the artery (p < 0.01), but the other three amino acids showed no significant differences. Significantly chronological changes in the difference between the blood levels in the JV and artery were observed for Glu. Measurement of the Glu level in the JV and artery may indicate gross metabolic change in the brain following TBI.

Adolescent↗

PubMed2002

Severe cerebral blood flow reduction inhibits nitric oxide synthesis.

The purpose of this study was to investigate the relationship between cerebral blood flow (CBF) and nitric oxide (NO) synthesis using a rat model of transient forebrain ischemia of varying severity. Forebrain ischemia was induced for 30 min by occlusion of the bilateral common carotid arteries without hemorrhagic hypotension. The production of NO end-products (nitrite and nitrate) was measured by in vivo microdialysis, and CBF by the hydrogen clearance technique. Ischemia induced NO synthesis, although the increase in the quantity of NO end-products was not remarkable during the ischemic period but became prominent after reperfusion. Such increases were abolished by Nomega-nitro-L-arginine methyl ester (L-NAME), although 7-nitroindazole (7-NI) appeared to have only slight effects. The production of NO end-products during ischemia increased when the CBF during ischemia was less than 60 mL/100 g/min. In animals in which the CBF during ischemia was higher than 22.7 mL/100 g/min, the production of NO end-products increased gradually after the induction of ischemia and reached a peak during the reperfusion period, whereas in other animals in which the CBF during ischemia fell below 22.7 mL/100 g/min, the NO end-products decreased during ischemia and increased transiently after reperfusion. These results suggest that the increase in NO end-products is NO synthase (NOS)-dependent and that most of the increase is derived from endothelial NOS. It is also suggested that NO synthesis during ischemia is closely related to CBF, and that severe CBF reduction may inhibit NO synthesis.

Animals↗

PubMed2002

Neoplastic cells and proliferating endothelial cells express connective tissue growth factor (CTGF) in glioblastoma.

Connective tissue growth factor (CTGF) was recently described as a cysteine-rich mitogenic peptide that is the prototypic member of the CCN family of protein including CTGF/fisp12, cef/10/cyr61 and nov. Recently CTGF was reported to have a function of mediating endothelial cell adhesion and migration through integrin alpha(v)beta3, promoting endothelial cell survival, and inducing angiogenesis in vivo. To clarify involvement of CTGF in tumor angiogenesis, using brain tissues with glioblastoma, we examined CTGF expression and localization by immunohistochemical staining and reverse transcription-polymerase chain reaction. The result showed that both glioblastoma tumor cells and proliferating endothelial cells are positive for CTGF by immunohistochemical staining, and CTGF mRNA expression was evaluated by RT-PCR in the brain tissues of glioblastoma. These findings suggest that CTGF may have the potential to stimulate angiogenesis in glioblastoma and function as an angiogenic factor in the process of tumor growth.

Adolescent↗

PubMed2002

Calcified metastatic brain tumor--two case reports.

A 29-year-old man and a 46-year-old woman presented with calcified brain metastasis from pulmonary adenocarcinoma. Both patients had a relatively benign clinical course and prolonged survival after total removal of the tumors. The male patient was still alive 2 years 3 months after surgical resection of the metastatic and primary tumors. The female patient had had brain metastasis 8 years after surgical resection of lung cancer, and survived for 3 years 3 months after removal of the brain metastasis. The MIB-1 indexes of the two cases were relatively low compared with other cases of brain metastases. Calcification and low MIB-1 index may indicate longer survival in patients with metastatic tumors if the primary tumor is controlled.

Adenocarcinoma↗

PubMed2002

Neuro-Behçet's disease manifesting as a neoplasm-like lesion--case report.

A 50-year-old man presented with neuro-Behçet's disease (NBD) manifesting as a large neoplasm-like lesion affecting the brainstem, basal ganglia, and white matter of the cerebral hemisphere. He had no history of disease except for psychoneurosis. On admission, neurological examination found left hemiparesis and dysarthria. Magnetic resonance (MR) imaging showed multiple small ring-like enhancement in the basal ganglia, brainstem, and deep white matter. Biopsy of the mass was performed. Histological examination revealed invasion of inflammatory cells in the white matter, especially around the blood vessels. After the brain biopsy, the patient developed oral aphthae, genital ulcers, and skin eruptions, which are indicative of Behçet's disease. MR imaging after three courses of steroid pulse therapy revealed that the edematous lesion had become smaller with minimum midline shift. NBD should be considered in the differential diagnosis of lesions with multiple ring-like enhancement extending from the basal ganglia to the brainstem, because dermatological manifestations are sometimes obscured during periods of remission.

Behcet Syndrome↗

PubMed2002

Endoscopic fenestration of posterior fossa arachnoid cyst for the treatment of presyrinx myelopathy--case report.

A 32-year-old man presented with an arachnoid cyst of the posterior fossa manifesting as cervical syringomyelic myelopathy. Magnetic resonance (MR) imaging demonstrated edematous enlargement and T2 prolongation of the cervical spinal cord, indicating a "presyrinx" state. MR imaging showed the inferior wall of the cyst, which disturbed cerebrospinal fluid (CSF) pulsatile movement between the intraspinal and intracranial subarachnoid spaces. The cyst wall was fenestrated with a neuroendoscope. The presyrinx state and the CSF movement improved. Posterior fossa arachnoid cyst, as well as Chiari malformation, can cause CSF flow disturbance at the craniocervical junction and syringomyelia. Endoscopic fenestration is less invasive than foramen magnum decompression and should be the procedure of choice.

Adult↗

PubMed2002

[A case of dural arteriovenous fistula of the inferior petrosal sinus successfully treated by transarterial and transvenous embolizations].

A 69-year-old male was admitted with chemosis and exophthalmos of his right eye. Angiograms revealed a dural arteriovenous fistula (AVF) involving the right inferior petrosal sinus. The AVF was fed by the right occipital and ascending pharyngeal arteries and drained into the cavernous sinus and right superior ophthalmic vein from the right inferior petrosal sinus. He was treated by transarterial embolization with polyvinyl alcohol in order to reduce the shunt-flow through the fistula. Then he was treated by transvenous embolization with GDC coils five days after the arterial embolization. Symptoms in his right eye have completely disappeared. Transvenous embolization combined with transarterial embolization is a useful and safe approach in the management of AVF involving the inferior petrosal sinus.

Aged↗

PubMed2002

[A case of a ruptured dermoid cyst in the sylvian fissure].

A 22-year-old woman was admitted to our department after developing a headache. The neurological findings were unremarkable on her first visit, but CT demonstrated a lot of low-density masses in the subarachnoid space. The largest mass was in the right sylvian fissure. These lesions appeared hyper-intense in T1, T2 and diffusion-weighted MR images. A right frontotemporal craniotomy was performed to remove the main mass lesion in the right sylvian fissure. During surgery, thickening of the arachnoid membrane and floating oily globules were seen in the subarachnoid space. The histopathological examination revealed that the tumor was a dermoid cyst. Follow-up MRI revealed that some of the small lesions had moved since the operation. These findings suggested that the tumor was a ruptured dermoid cyst. The patient's postoperative course was uneventful and her headache disappeared completely.

Adult↗

PubMedDate not supplied

Evaluation of cerebral perfusion parameters measured by perfusion CT in chronic cerebral ischemia: comparison with xenon CT.

PURPOSE: The purpose of this work was to evaluate the usefulness of perfusion CT in the evaluation of patients with chronic cerebral ischemia by comparing it with xenon CT (Xe-CT). METHOD: Cerebral blood flow (CBF) of perfusion CT (CBFper) and time to peak (TTP) were compared with the CBF of Xe-CT (CBFxe) in 18 patients. Cerebral blood volume (CBV) was compared with cerebral vascular reserve (CVR) in 10 of 18 patients who underwent pre- and postacetazolamide Xe-CT. RESULTS: CBFper and TTP demonstrated a high correlation with CBFxe in relative values by side-to-side comparisons (r = 0.743, p < 0.0001 and r = -0.760, p < 0.0001, respectively). There was a negative correlation between relative CBV and relative CVR (r = -0.637, p = 0.0025). Visually, territories with delayed TTP corresponded well to those of decreased CBFxe, but these territories tended to be larger in TTP maps. CONCLUSION: Perfusion CT is a useful tool to evaluate chronic hemodynamic disturbance and can be an alternative method for those using acetazolamide challenge.

Adult↗