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Biomedical subjects

Kaoru Kurisu

Publications and source records attributed to Kaoru Kurisu.

At least 55 records · Page 3Linked to original sources
PubMed2003

Staurosporine-induced apoptosis is independent of p16 and p21 and achieved via arrest at G2/M and at G1 in U251MG human glioma cell line.

OBJECTIVE: The mechanisms involved in the cell cycle and cell death remain unresolved despite much investigation. Staurosporine induces cell death and G1 or G2/M arrest in a dose-dependent manner, but the mechanisms remain unknown. METHODS: In the present study an adenovirus vector expressing p16 or p21 genes in human glioma cell lines was used to examine cell cycle regulation and cell death induced by staurosporine. RESULTS: A low concentration (</=10 n M) of staurosporine induced G1 arrest of U251MG cells, whereas a high concentration (>/=30 n M) induced G2/M arrest and finally induced apoptosis via a caspase-3-activated pathway from both the G2/M and G1 phases. However, pRb was dephosphorylated and cdc2 was inhibited at both the low and the high concentrations of staurosporine, indicating that the mechanisms of cell cycle regulation are not simply p53-Rb- or cdc2-dependent pathways. CONCLUSIONS: Forced G1 arrest by transfection with p16 or p21 genes did not alter the rate of staurosporine-induced cell death. This implies that an unknown pathway of apoptosis occurs from the G1 phase.

Adenoviridae↗
PubMed2003

Expression of survivin in astrocytic tumors: correlation with malignant grade and prognosis.

BACKGROUND: Astrocytic tumors are the most common tumors of the central nervous system. The mechanisms of genetic change of astrocytic tumors have not been understood completely. Recently, survivin has been identified as a member of the inhibitor-of-apoptosis family. Survivin expression is considered an important prognostic factor of many tumors. METHODS: The authors investigated 43 astrocytic tumors (8 diffuse astrocytomas; 15 anaplastic astrocytomas; 20 glioblastomas). The authors examined survivin mRNA expression in tumor specimens by reverse transcriptase-polymerase chain reaction amplification. The authors analyzed the relationship between survivin expression and other molecular changes commonly found in astrocytic tumors [p53 alteration, overexpression of epidermal growth factor receptor (EGFR), and bcl-2 expression]. RESULTS: Thirty-four of 43 (79.1%) astrocytic tumors expressed survivin. The distributions included 3 of 8 (37.5%) diffuse astrocytomas, 13 of 15 (86.7%) anaplastic astrocytomas, and 18 of 20 (90.0%) glioblastomas. Expression of survivin (P = 0.0057) and EGFR (P = 0.0112) was significantly associated with malignant grade of astrocytic tumors, but expression of p53 (P = 0.1893) and bcl-2 (P = 0.2552) was not. Furthermore, patients with survivin-positive astrocytic tumors had significantly shorter overall survival times compared with patients who had survivin-negative tumors (P = 0.0271). CONCLUSIONS: Survivin expression in astrocytic tumors varies with histologic malignancy and may play an important role in the oncogenesis and progression of astrocytic tumors. These data suggest that survivin has great potential as a therapeutic target in astrocytic tumors.

Adolescent↗
PubMed2003

Long-term results of conventional treatment of diencephalic pilocytic astrocytoma in infants.

BACKGROUND: To develop an effective therapeutic strategy for patients with diencephalic pilocytic astrocytomas (PA), we must understand the long-term effects and problems of conventional treatments. METHODS: We performed a retrospective follow-up of four infants with PA in the diencephalon. CONCLUSION: The initial treatment consisted of partial tumor removal and/or external radiation. The mean progression-free duration after the initial treatment was 108.5 months. All patients received a second course of radiation to treat recurrent tumors. These conventional treatments produced relatively long survival. Three patients died 105, 202, and 379 months after the initial treatment. One patient is still alive at 249 months after the initial treatment. However, mental retardation was obvious in all four patients 6 to 12 years after the first irradiation and within 2 years of the second course of irradiation. Therefore, new therapeutic strategies must focus on delaying the timing of radiation until the patients are at least 5 years old and avoiding a second course of radiation to treat recurrence.

Astrocytoma↗
PubMed2003

Interhemispheric arachnoid cyst in the elderly: case report and review of the literature.

BACKGROUND: Preoperative differential diagnosis of interhemispheric cysts is sometimes difficult. CASE DESCRIPTION: We recently experienced a case of symptomatic interhemispheric arachnoid cyst in a 62-year-old woman. We reviewed interhemispheric arachnoid cysts in the elderly and the management of symptomatic interhemispheric arachnoid cysts in elderly patients. Symptomatic interhemispheric arachnoid cysts in the elderly are predominantly located on the right side, have a long history of progressive symptomology, occur predominantly in females, and have no communication with the subarachnoid space. Interhemispheric arachnoid cysts are usually not associated with agenesis of the corpus callosum in elderly patients, whereas interhemispheric nonarachnoid cysts are usually associated with agenesis of the corpus callosum, which will be clearly demonstrated on magnetic resonance imaging. CONCLUSIONS: It is highly possible that an interhemispheric cyst without agenesis of the corpus callosum in an adult is an arachnoid cyst.

Arachnoid Cysts↗
PubMed2003

De novo distal posterior cerebral artery aneurysm.

BACKGROUND: De novo aneurysms in the posterior circulation are very rare. The authors describe a first case of ruptured de novo posterior cerebral artery (PCA) aneurysm in the P3 portion. CASE DESCRIPTION: A 52-year-old woman with ruptured de novo P3 aneurysm was treated by early endovascular obliteration using Guglielmi Detachable Coils (GDC). To prevent vasospasm, she received postoperative treatment with a hypertensive hypervolemia dilution and a calcium antagonist. She was discharged without neurologic deficits. CONCLUSIONS: Aneuryms arising from peripheral segment of PCA are rare, and delayed surgical clipping has been recommended for these lesions. This is the first report of a de novo P3 ruptured aneurysm treated by endovascular embolization using GDC in the acute stage of subarachnoid hemorrhage. The characteristics of de novo posterior circulation aneurysms and the strategy for the distal PCA aneurysms are discussed.

Adult↗
PubMed2003

Case of clear cell ependymoma of medulla oblongata: clinicopathological and immunohistochemical study with literature review.

Clear cell ependymoma has been included in the WHO classification of the central nervous system in 1993, after the first report by Kawano et al. Since then, only a few cases have been reported. Most clear cell ependymoma cases reported in the literature so far were located in the supra-tentorial compartment and/or cerebellum, and one case was in the cervical spinal cord. We report a case of clear cell ependymoma whose histological features were sufficient for the diagnosis and was unusually located in the fourth ventricle originating from the medulla oblongata. The tumor showed uniform tumor cells with perinuclear halo, nuclei being centrally located. Most of the tumor cells were arranged as perivascular pseudorosettes, and no ependymal canals or rosettes were evident. Mitotic figures were not frequent. Immunohistochemically, the tumor cells were strongly reactive for glial fibrillary acidic protein and vimentin, and weak and dot-like positive for epithelial membrane antigen. Clear cell change of the tumor cells appeared to be fixation artifact because this feature was not evident in the frozen section.

Adult↗
PubMed2003

Involvement of Ca(2+) channels in abnormal excitability of hippocampal CA3 pyramidal cells in noda epileptic rats.

Noda epileptic rat (NER) is a mutant rat, which spontaneously exhibits a tonic-clonic convulsion from 14 weeks of age. An intracellular recording study was performed to elucidate the abnormal excitability of NER hippocampal CA3 neurons. The recorded neurons were classified into two groups, group A and B neurons, according to the responses to a single stimulation of mossy fibers. In group A neurons, a stimulus elicited a long-lasting depolarization shift accompanying repetitive firings followed by after-hyperpolarization. In group B neurons, the same stimulus elicited a single spike without a long-lasting depolarization shift. Bath application of 1 mM Cd(2+), a nonselective Ca(2+) channel blocker, completely inhibited the abnormal excitation in group A neurons. We further examined the character of Ca(2+) spikes in NER CA3 neurons. Ca(2+) spikes were completely blocked by 10 microM Cd(2+) in group A neurons, but not in either group B or control neurons, suggesting that Ca(2+) channels in NER group A neurons have the hypersensitivity to Cd(2+). Analysis using subtype specific blockers of Ca(2+) channel raised the possible involvement of T-type Ca(2+) channels. These results suggest that Ca(2+) channel dysfunction is involved in the abnormal excitability of CA3 pyramidal neurons and pathogenesis of epilepsy in NER.

Animals↗
PubMed2003

Mortality in 154 surgically treated patients with acromegaly--a 10-year follow-up survey.

To determine the effects of surgery and adjuvant therapy on the mortality rate of Japanese patients with acromegaly, 154 surgically treated patients were followed until death or December 2000. Mean follow-up period was 10.0 +/- 6.5 (SD) years. Postoperative GH levels, mean values of GH levels measured in the first postoperative month, were <2.5 ng/mL in 73 (47.4%), 2.5-5.0 ng/mL in 50 (32.5%), and >5.0 ng/mL in 31 patients (20.1%). Three of 123 patients with postoperative GH levels <5.0 ng/mL underwent a second transsphenoidal surgery (TSS), the other 120 received no further treatment. Additional treatments, including second TSS, medical treatment, and gamma-knife irradiation for residual tumor, were administered to 25 of 31 patients whose postoperative GH was >5.0 ng/mL. Among the total 154 patients surveyed, 11 (7.1%) died during the follow-up period. The standard mortality ratio (SMR) was 1.17, not different from age- and sex-matched controls. The SMR of the 72 patients with postoperative GH <2.5 ng/mL was better than that of the 51 patients whose postoperative GH was 2.5-5.0 ng/mL (1.09 vs. 1.64); however, the difference was not statistically significant. In conclusion, TSS and adequate adjuvant treatment decreased the excess mortality rate of acromegalics to nearly the same level as that of the general Japanese population.

Acromegaly↗
PubMed2003

Hyperemia prior to acute brain swelling during rewarming of patients who have been treated with moderate hypothermia for severe head injuries.

OBJECT: The goal of this study was to elucidate the optimal time for rewarming of patients who have been treated with hypothermia for severe head injury. METHODS: Eleven patients with severe head injuries who had been treated by hypothermia underwent transcranial Doppler (TCD) ultrasonography examinations. The patients were divided into two groups: Group A consisted of three patients in whom acute brain swelling occurred during the rewarming period and Group B was composed of eight patients who displayed no significant intracranial hypertension during or after hypothermia therapy. In all patients, the mean flow velocity of the middle cerebral artery (FV(MCA)) recorded transcranially and the mean flow velocity of the internal carotid artery (FV(ICA)), recorded high in the neck, were monitored at 24-hour intervals after the patient was admitted to the hospital. In Group A, the FV(MCA) was normal at 48 hours (maintenance state of hypothermia) in each patient, and abnormal increases and peak values (> 100 cm/second) occurred from 96 to 144 hours postinjury (rewarming period). The FV(ICA), which was monitored concurrently also varied as the FV(MCA) increased. The pulsatility indices in the arteries decreased at the time of the peak FV(MCZ). The enhanced FV(MCA) was consistent with hyperemia because of the low FV(MCA)/FV(ICA) ratios (< 3). Two patients in whom jugular venous oxygen saturation was monitored were found to have high values (> 80%), representing hyperemia. All intracranial pressures (ICPs) that lay within the normal range at 48 hours postinjury elevated acutely after the peak FV(MCA). In Group B, both FV(MCA) and FV(ICA) values were normal at 48 hours postinjury and remained stable throughout the rewarming period. Values of ICP were also maintained within the normal range until the patients were weaned from hypothermia therapy. CONCLUSIONS: Hyperemia, detectable by TCD ultrasonography, may serve as an index in the prediction of acute brain swelling, and rewarming should be terminated when such a hemodynamic phenomenon is observed.

Acute Disease↗
PubMed2003

[Contrast enhanced fast fluid-attenuated inversion-recovery MR imaging for diagnosing cerebral venous angioma: report of two cases].

It has been reported that contrast-enhanced fluid-attenuated inversion-recovery (FLAIR) sequences were useful for detecting superficial abnormalities, such as meningeal disease, because they do not demonstrate contrast enhancement of cortical vessels with slow flow as do T1-weighted images. We reported the usefulness of contrast-enhanced FLAIR images to differentiate cerebral venous angioma from tumor in two patients. Case 1 was a 71-year-old man developed cortical hemorrhage. Post contrast-enhanced T1-weighted images showed an enhanced lesion around the hematoma, whereas contrast-enhanced FLAIR images showed no enhancement of the lesion, thus he was diagnosed as cortical hemorrhage from cerebral venous angioma. Case 2 was a 72-year-old woman, who was examined MR images because of the jugular foramen neurinoma. There was a T2-high-intensity lesion in the right frontal lobe, and post contrast-enhanced T1-weighted images showed an enhanced lesion in and around the T2-high-intensity lesion. Post-contrast FLAIR images showed no enhancement, and she was diagnosed as cerebral venous angioma. Contrast-enhanced fast FLAIR sequences was useful in differentiation between venous angiomas and tumors. Identification of these lesions was due to the flow-void phenomenon in vessels with slow-flowing blood such as venous angioma, which could not be differentiated from tumors on T1-weighted images.

Aged↗
PubMed2002

Epileptiform burst discharges in hippocampal CA3 neurons of young but not mature Noda epileptic rats (NER).

Noda epileptic rat (NER), originally found in a colony of Crj; Wistar rats, shows spontaneous tonic-clonic convulsion characterized by the appearance of high voltage polyspikes in cortical and hippocampal EEG once every 2-3 days after 2-4 months of age. Electrophysiological studies using hippocampal slice preparations of NER were performed to determine whether hippocampal neurons have abnormal excitability. When a single stimulus (1-25 V) was delivered to the mossy fibers of NER at 4-6 weeks old before they showed any seizures, a long-lasting depolarization shift (DS) accompanied by repetitive firings and after-hyperpolarization following the abnormal firing was observed in seven of 14 hippocampal CA3 neurons. A lower stimulation intensity evoked DS and abnormal firing in three of nine CA3 neurons of NER at 10-15 weeks old which had already showed seizures at 10-15 weeks of age. However, the abnormal firing was not observed in any 10 neurons of the animals at more than 20 weeks old nor in Wistar rats. The input impedances of CA3 neurons in NER with abnormal firing were lower than those without abnormal firing and those in Wistar rats. The abnormal excitability obtained in NER at an age when it did not display any seizures suggests that the hippocampus may play a role in epileptogenicity in NER.

Action Potentials↗
PubMed2002

Effects of vigabatrin on epileptiform abnormal discharges in hippocampal CA3 neurons of spontaneously epileptic rats (SER).

Vigabatrin, a gamma-amino butyric acid (GABA) transaminase inhibitor, is known to inhibit partial epilepsy in humans. The spontaneously epileptic rat (SER), a double mutant (zi/zi, tm/tm), exhibits both tonic convulsion and absence-like seizures from the age of 8 weeks. Hippocampal CA3 pyramidal neurons in SER show a long-lasting depolarization shift with accompanying repetitive firing when a single stimulus is delivered to the mossy fibers in slice preparations. The effects of vigabatrin on the abnormal excitability of hippocampal CA3 pyramidal neurons in SER were examined to elucidate the mechanism underlying the antiepileptic action of the drug. Intracellular recordings were performed in 24 hippocampal slice preparations of 20 SER aged 8-17 weeks old. Bath application of vigabatrin (1 mM) inhibited the depolarizing shifts with repetitive firing induced by mossy fiber stimulation in 15 min without affecting the first spike and resting membrane potentials in hippocampal CA3 neurons of SER. A higher dose of vigabatrin (10 mM) sometimes inhibited the first spike. However, vigabatrin at doses up to 10 mM did not significantly affect the single action potential elicited by stimulation of the mossy fibers in the hippocampal CA3 neurons of age-matched Wistar rats. In addition, application of vigabatrin (10 mM) did not significantly affect the firing induced by depolarizing pulse applied in the CA3 neurons of the SER, nor the miniature excitatory postsynaptic potential (mEPSP) recorded in the CA3 neurons of SER. The inhibitory effect of vigabatrin (1 mM) on the mossy fiber stimulation-induced depolarization shift with repetitive firing was blocked by concomitant application of bicuculline (10 microM), a GABA(A) receptor antagonist. These findings strongly suggested that GABA increased by inhibition of GABA transaminase with vigabatrin inhibits abnormal excitation of hippocampal CA3 neurons of SER via GABA(A) receptors, although the possibility that the drug acted directly on the GABA(A) receptors of CA3 neurons could not be completely excluded.

Action Potentials↗
PubMed2002

Good clinical course in infants with desmoplastic cerebral neuroepithelial tumor treated by surgery alone.

We investigated why surgery alone provides for a benign clinical course in patients with desmoplastic infantile ganglioglioma and astrocytoma (DIG/A). The clinical course of 4, less than six-month-old girls, surgically treated at our institutions, was evaluated retrospectively. All presented with the clinical symptom of increasing head circumference. CT and MRI scans revealed a solid tumor attached to the dura that was surrounded by large, multiple cysts, in fronto-temporo-parietal lobe. Gross total removal succeeded in all 4 cases because the solid components of the tumor were very firm in contrast to the soft adjacent brain tissue. Microscopically, the surgical specimens consisted almost entirely of dense fibrous connective tissue containing generally elongate cells with inconspicuous cytoplasm. Most of these cells were immunopositive for GFAP. There was no evidence of tumor cells in the cyst wall. In 3 cases, some small neurons were positive for neurofilament immunostain. A high proportion of undifferentiated small cells in a less demoplastic area far from the dura were immunopositive for MIB-1. All of the 4 patients have been free of recurrence for more than five years. In patients with DIG/A, there are 5 reasons for a good clinical course. [1] At surgery, the tumor margin is clearly discernible because of the difference between the solid tumor and the soft adjacent brain tissue. [2] The tumor is located in the superficial cerebral hemisphere. [3] Large, multiple cysts surround the tumor. [4] The growth point appears to be adjacent to the cysts. [5] The cyst walls are free of invading tumor cells.

Astrocytoma↗
PubMed2002

Intrasellar pleomorphic xanthoastrocytoma: case report.

OBJECTIVE AND IMPORTANCE: A patient with a primary intrasellar pleomorphic xanthoastrocytoma is described. CLINICAL PRESENTATION: A 78-year-old woman experienced slowly progressing bilateral visual disturbance. Analysis of magnetic resonance imaging scans indicated a well-enhanced tumor occupying intra- and suprasellar spaces with displacement of the pituitary gland anteriorly. INTERVENTION: Partial resection of the tumor via the transsphenoidal route brought about improvement of the patient's visual disturbance. The tumor was conspicuously pleomorphic and composed of plump to spindle-shaped large and bizarre cells with single or multiple nuclei and lipid-laden foamy cytoplasm. The neoplastic cells were positive for glial fibrillary acidic protein, S-100 protein, and vimentin. The MIB-1 antibody labeling index was very low (<1%) CONCLUSION: Pleomorphic xanthoastrocytoma should be included in the differential diagnosis of tumors arising in the posterior hypophysis.

Aged↗
PubMed2002

Intradiploic arachnoid cyst identified by diffusion-weighted magnetic resonance imaging--case report.

A 72-year-old woman presented with an intradiploic arachnoid cyst in the occipital intradiploic space which was found incidentally by magnetic resonance (MR) imaging. Computed tomography revealed a widened diploic space and thinning of the inner and outer tables of the occipital bone. The cyst appeared as isointense to the cerebrospinal fluid on both T1- and T2-weighted images. The differential diagnosis of intradiploic epidermoid cyst could be excluded because the lesion was low intensity on diffusion-weighted MR images. Arachnoid cyst is a benign lesion, so exploratory surgery should be avoided unless the cyst is symptomatic. Diffusion-weighted MR imaging is an effective modality to distinguish diploic epidermoid cysts from arachnoid cysts.

Aged↗
PubMed2002

Myelodysplastic syndrome following therapy for brain tumor--two case reports.

A 3-month-old boy and a 29-year-old woman presented with myelodysplastic syndrome (MDS) following therapy for primary malignant brain tumor. Both received intensive alkylating agent doses for induction and maintenance chemotherapy combined with craniospinal or cranial radiation for medulloblastoma and anaplastic astrocytoma, respectively. They developed refractory anemia and pancytopenia. Approximately 9 years after the completion of induction chemoradiotherapy, chromosomal analysis of bone marrow cells resulted in the diagnosis of MDS. The boy died of leukemic evolution 15 months later, the woman died of hematopoietic failure 3 months later. The most common symptom of MDS is refractory anemia, either alone or as part of bi- or pancytopenia. Clonal proliferation with chromosomal analysis of bone marrow cells establishes the diagnosis of MDS. Patients with malignant brain tumors are at risk of the development of MDS as a late complication of chemotherapy based on high cumulative doses of alkylating agents.

Adult↗