Biomedical subjects

T Yoshimine

Publications and source records attributed to T Yoshimine.

At least 127 records · Page 7Linked to original sources

PubMed1996

Cellular targets of exogenous tumour necrosis factor-alpha (TNF alpha) in human gliomas.

To identify the cellular targets of TNF alpha in human gliomas, a total of 30 surgical specimens (12 glioblastomas, 4 anaplastic astrocytomas, 3 astrocytomas, 7 brains adjacent to tumour (BAT), 4 histologically normal-appearing brains) were examined by in vitro binding technique using biotinylated TNF alpha. The TNF-binding sites (TNF-BS) were recognized in the tumour cells in 8 of the 12 glioblastomas, 3 of the 4 anaplastic astrocytomas and in all the 3 astrocytomas. The TNF-BS were also recognized in the vascular endothelial cells in all these cases. The presence of TNF-BS in blood vessels ranged from 7.7 to 74.4% of the background vessels. This wide range of variation in the presence of TNF-BS within the tumour cells and tumour blood vessels may be relevant to the variable response of individual tumours to TNF alpha therapy. Since the tissue of normal brain, which lacks TNF-BS, might hardly be affected by this cytokine, administration of TNF alpha may be considered as an adjuvant therapy in selected groups of patients.

Binding Sites↗

PubMed1996

Accumulation of allelic losses on chromosome 10 in human gliomas at recurrence.

Aims-To elucidate the implications of allelic loss on chromosome 10 in the malignant progression of human gliomas.Methods-Eight microsatellite loci (D10S249, D10S191, D10S210, D10S219, D10S246, D10S222, D10S221, and D10S212) were analysed for chromosomal deletions in histologically benign and malignant, including recurrent, gliomas. Of the 16 original tumours studied (two astrocytomas, nine anaplastic astrocytomas and five glioblastomas), the histological diagnosis at recurrence was anaplastic astrocytoma in six cases and glioblastoma in 10. Genomic DNA was extracted from formalin fixed, paraffin wax embedded sections. Samples of original and recurrent tumours were paired and amplified using PCR. Samples of histologically normal brain served as controls.Results-Of the original tumours, all five glioblastomas, five (56%) of nine anaplastic astrocytomas and none of the astrocytomas demonstrated loss of heterozygosity (LOH) on chromosome 10. Additional LOH was detected in the five cases of anaplastic astrocytoma that progressed to glioblastoma at recurrence. Additional LOH was not detected in the two cases of astrocytoma that progressed to anaplastic astrocytoma at recurrence. With the exception of one case, additional LOH was observed in the recurrent glioblastomas.Conclusion-LOH was observed at the loci of two adjacent microsatellite markers, D10S222 and D10S221 (10q23-q25), suggesting that this region on chromosome 10 is closely related to progression from anaplastic astrocytoma to glioblastoma.

Journal Article↗

PubMed1996

Generation of nitric oxide and superoxide during reperfusion after focal cerebral ischemia in rats.

We investigated the levels of nitrosyl hemoglobin (HbNO) in rat jugular blood by electron spin resonance (ESR) spectroscopy during and after middle cerebral artery occlusion. The levels of plasma nitric oxide (NO) end products, nitrate plus nitrate, were compared with the levels of HbNO. Small amounts of HbNO were detected in sham-operated rats (n=4) and those subjected to 2 h of occlusion (n=4), whereas nitrite plus nitrate was increased only in the latter (P<0.01; vs.sham). Upon reperfusion after 2 h of occlusion both HbNO and nitrite plus nitrate clearly increased after 15 min (n=4) and 30 min (n=6) reperfusion (P<0.01; vs.occlusion). Administration of superoxide dismutase (5 mg/kg) significantly increased HbNO (P<0.05) but not plasma nitrate plus nitrate (n=5). The increase in HbNO suppressed by administration of NG-nitro-L-arginine methyl ester (20mg/kg; n=4,P<0.01), and this suppression could be reversed by L-arginine (200 mg/kg) (n=4). The present study clearly showed that the L-arginine-NO synthase pathway was activated during reperfusion after focal cerebral ischemia and indicated the involvement of a reaction between NO and superoxide during early reperfusion.

Animals↗

PubMed1996

Morphological effects of tumor necrosis factor-alpha on the blood vessels in rat experimental brain tumors.

The morphological changes in the vascular endothelium caused by the administration of tumor necrosis factor-alpha (TNF-alpha) were studied in an experimental model of rat brain tumors. Wistar rats bearing implanted C6 glioma received human natural-type TNF-alpha (1.7 x 10(5) U/m2) through the carotid artery and were sacrificed 3 or 24 hours later. The endothelial cells of the tumor blood vessels, demonstrated by the immunoreaction to factor VIII-related antigen, were enlarged after TNF-alpha administration. Morphometry demonstrated that the nuclei of these endothelial cells were also increased in size. The endothelial cells in the brain remote to the tumor were not affected. An in vitro binding study demonstrated that TNF-alpha binding sites were distributed in the vascular endothelial cells within the tumor but not in the brain remote to the tumor. The selective effect of TNF-alpha on the tumor blood vessels in experimental brain tumors may be related to the selective distribution of the TNF-alpha binding site.

Animals↗

PubMed1996

Asymptomatic hypothalamic hamartoma associated with an arachnoid cyst--case report.

A 42-year-old male presented with the complaint of mild left facial numbness. Magnetic resonance imaging demonstrated a solid tumor in the interpeduncular cistern and a huge arachnoid cyst in the left middle cranial fossa. The tumor appeared isointense to the surrounding cerebral gray matter on T1-weighted images and hyperintense to that on T2-weighted images. The tumor was partially resected. Histological findings were characteristic of hamartoma. The mild left facial numbness was probably due to compression of the left trigeminal nerve by the arachnoid cyst. Asymptomatic hypothalamic hamartomas may occur in adults with atypical clinical presentations.

Adult↗

PubMed1995

Effects of superoxide dismutase on nitric oxide production during reperfusion after focal cerebral ischemia is rats.

To assess the interaction of nitric oxide (NO) and superoxide during reperfusion after cerebral ischemia, we studied the dose effects of superoxide dismutase (SOD) on the levels of nitrosyl hemoglobin and plasma nitrite + nitrate which were increased at 30 min reperfusion after 2 h middle cerebral artery occlusion in rats. SOD was administered at 10 min before reperfusion. With 1, 5 and 10 mg/Kg of SOD, plasma nitrite + nitrate level was decreased by 25 mg/kg of SOD. The same amount of apo enzyme was without effect. These results suggest effect of superoxide in the NO level released during reperfusion after cerebral ischemia.

Animals↗

PubMed1995

Increase in plasma nitric oxide end products following rat cortical injury.

The changes in plasma nitric oxide (NO) end products, nitrite (NO2-) and nitrate (NO3-), were studied following cortical injury in rats. At 3 days after stereotactic cortical injury (day 3), plasma NO end products were significantly increased (P < 0.01), and decreased by day 7. This increase on day 3 was inhibited by a selective inhibitor of inducible NO synthase (NOS), aminoguanidine (100 mg/kg, i.p. on days 1 and 2, P < 0.001). The present study first demonstrated the temporary increase in plasma NO end products, which is attributable to the inducible NOS activation after cerebral injury.

Animals↗

PubMed1995

Early blood-brain barrier disruption after high-dose single-fraction irradiation in rats.

We studied the effect of high-dose single-fraction irradiation on the permeability of the blood-brain barrier (BBB) in rat brains. Immunohistochemistry with an antibody to serum albumin was used as a sensitive method for detecting the extravasation of endogenous serum components. Extravasation of albumin was detected as early as 1 day after irradiation with 20 or 40 Gy. Immunoreactivity reached its maximum after 3 days, gradually decreased during the following few weeks and had disappeared by day 30. Extravasation was much greater after irradiation with 80 Gy and continued to increase during the whole period of the experiment (6 days). Disruption of BBB this early after irradiation has not been previously documented. The time course of observed serum albumin extravasation, however, agrees well with the previous ultrastructural evidence for increased BBB permeability after irradiation with 27 Gy in monkey brains. This transient impairment of BBB may contribute to the reversible neurological symptoms after radiosurgery. It may also allow drugs that normally not pass the BBB to do so and thus disperse in the brain when administered at this time.

Animals↗

PubMed1995

Reaction of microglial cells and macrophages after cortical incision in rats: effect of a synthesized free radical scavenger, (+/-)-N,N'-propylenedinicotinamide (AVS)

Reactive microglial cells and macrophages appear after trauma to the brain. To investigate the accumulation patterns of reactive microglial cells and macrophages after cortical incision, these cells were stained immunohistochemically with anti-ED1 antibody in the brain sections before and 1, 3, 5, and 7 days after incision. And to ascertain the participation of oxygen free radicals in these cellular reactions, a synthesized free radical scavenger, (+/-)-N,N'-propylenedinicotinamide (AVS) was administered in this model. Rats were administered AVS (300 mg/kg, i.p.) 30 min before, 2.5 h and every 24 h after incision (AVS group), while only saline was administered in the same manner as a control (saline group). In the saline group, both reactive microglial cells and macrophages had already appeared on day 1 post-incision. The former continued to increase in number during the following days, whereas the latter increased in number up to day 3 and thereafter decreased. Both the numbers of reactive microglial cells and macrophages were significantly decreased (P < 0.05) in the AVS group on days 5 and 7. The results suggest the participation of oxygen free radicals in the reaction of microglial cells and macrophages in traumatic brain injury.

Animals↗

PubMed1995

Endoscopic-image display system mounted on the surgical microscope.

This report describes a newly developed endoscopic-image display system which is mounted on the optical unit of the surgical microscope. This system permits the neurosurgeon to watch the endoscopic image through one of the eye lenses of a surgical microscope during application of neurosurgical endoscopy under open microsurgical procedures. It frees the neurosurgeon from the major conventional inconvenience that he has to discontinue watching the microscopic view in order to look at the endoscopic images through the ocular of the endoscope or on the video monitor.

Brain Diseases↗

PubMed1995

Expression of bone-related protein messenger RNA in human meningiomas: possible involvement of osteopontin in development of psammoma bodies.

Meningiomas often contain concentric calcified foci, referred to as psammoma bodies. Since calcium phosphate deposits in both psammoma bodies and bone tissues, we examined whether messenger (m) RNA of bone-related extracellular matrix proteins and bone morphogenetic proteins (BMP) were expressed in human meningioma tissues. Northern blotting demonstrated the expression of osteopontin (OPN), matrix Gla protein (MGP), osteonectin (ON) and BMP-4 mRNA but not bone sialoprotein, osteocalcin and BMP-2 mRNA. In situ hybridization revealed that most OPN mRNA-expressing cells were located around the psammoma bodies in meningothelial whorls. Moreover, combination of in situ hybridization and immunohistochemistry on serial sections showed that the OPN mRNA-expressing cells were CD68-positive, suggesting they were macrophages. Immunohistochemistry with anti-OPN antibody and von Kossa staining on the adjacent section showed that the deposition site of OPN protein was consistent with that of calcium phosphate. Neither MGP nor ON mRNA expression appeared to correlate with the calcification. The present result suggests that OPN produced by CD68-positive macrophages may play a significant role for development of psammoma bodies in meningiomas.

Antibodies, Monoclonal↗

PubMed1995

[Comparison between anomia with word comprehension difficulty and Gogi aphasia due to lobar atrophy].

We used naming and pointing tests and a proverb completion task to compare two cases of aphasia that exhibited a selective disturbance of word processing. One patient had anomia with word comprehension difficulty due to partial ablation of the left temporal lobe and the other patient had Gogi aphasia due to lobar atrophy with left temporal predominance. We presented 90 pictures of common objects divided into 9 categories in the naming and pointing tests, and used 10 well-known Japanese proverbs as stimuli in the proverb completion task. Performance of the naming and pointing tests was severely impaired in both patients. In the patient with anomia, words the patient could not name or point to varied from session to session and phonemic cue effects were frequently observed. The proverb completion phenomenon was positive. These findings indicate that the patient had an obstruction of the access route to the intact word store or a partial rarefaction of the word store itself. In the patient with Gogi aphasia, the words the patient could not name or point to were consistent from one occasion to another, and no phonemic cue effects or signs of familiarity were observed at all. The proverb completion phenomenon was totally negative. These findings indicate that the patient has lost the word store itself. MR images in the case of anomia revealed a lesion extending from the anterior to the central portion of the inferior part of the left temporal lobe. In the case of Gogi aphasia, the MR images displayed knife-edged focal atrophy in the anterior aspect of both temporal lobes, more prominently on the left.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Nitrosyl hemoglobin production during reperfusion after focal cerebral ischemia in rats.

We first detected a definite nitrosyl hemoglobin (HbNO) signal in the jugular blood by electron spin resonance spectroscopy during early reperfusion after cerebral ischemia. A distinct three-line hyperfine structure, characteristic to HbNO, was demonstrated at 30 min of recirculation after 2 h of middle cerebral artery occlusion in rats. Only a weak HbNO signal was observed in animals with 2 h sustained ischemia or with sham operation. The present findings suggest that reperfusion after cerebral ischemia facilitates nitric oxide generation in the brain, which leads to the increased nitrosylation of erythrocyte hemoglobin in the cerebral circulating blood.

Animals↗

PubMed1994

Altered expression of antithrombotic molecules in human glioma vessels.

A total of 14 surgical specimens, including 7 glioblastomas, 3 anaplastic astrocytomas, 2 brains adjacent to glioblastoma and 2 grossly normal brains, were investigated immunohistochemically for the expression of antithrombin III (AT-III), heparan sulfate proteoglycan (HSPG) and thrombomodulin (TM) in the endothelium of microvessels. The immunoreaction to AT-III was of moderate intensity in grossly normal brains, brains adjacent to glioblastoma, and anaplastic astrocytomas, but was only weak in glioblastomas, especially in the capillaries. The immunoreaction to HSPG was constantly intense in the microvessels in all the specimens. Although the immunoreaction to TM was negative or only faint in the microvessels in grossly normal brains, it was moderately to strongly intense in anaplastic astrocytomas and brains adjacent to glioblastoma. The intensity of immunoreaction to TM was variable, from faint to strong in the capillaries, and moderate to strong in larger microvessels in glioblastomas. The present study suggested that the alterations in the expression of those antithrombotic molecules could explain, at least in part, the tendencies for intratumoral hemorrhage as well as intravascular thrombosis in the different areas of malignant gliomas.

Antithrombin III↗

PubMed1994

Expression of thrombomodulin in astrocytomas of various malignancy and in gliotic and normal brains.

A total of 22 surgical specimens, 16 astrocytomas with various malignancy, 3 brains adjacent to tumor and 3 brains with non-neoplastic lesion, was investigated immunohistochemically for the expression of thrombomodulin (TM). This membrane protein is localized on the vascular endothelium of nearly every human tissue and plays a crucial role in the maintenance of antithrombotic property of the endothelial cells. Although the normal cerebral vessels were negative for TM, the tumor vessels were positive for TM. The increased expression of TM was, however, demonstrated not only in glioblastomas but also in low-grade astrocytomas. Furthermore, the vessels in the brains adjacent to tumor and gliotic brains were also positive for TM. Those observations suggested that the tendency of intratumoral bleeding, which is rather characteristic of glioblastomas, is not simply explained by the altered expression of vascular endothelial TM. In two cases of glioblastoma, not only the blood vessels but also the tumor cells were positive. Considering the mitogenic activity of thrombin, a ligand for TM, the increased expression of TM might be related to the tumor neovascularization and also the tumor growth.

Astrocytoma↗

PubMed1994

Complete regression of anaplastic astrocytoma by intravenous tumor necrosis factor-alpha (TNF alpha) after recurrence: a case report.

A 61-year-old male patient had a recurrence of anaplastic astrocytoma after initial chemoradiotherapy. After histologic confirmation of the recurrent tumor, he was treated with intravenous administration of human natural tumor necrosis factor-alpha (TNF alpha). Morphometric analysis of the tumor volumes demonstrated that the tumor continued to regress for 8 months during the course of intravenous TNF alpha therapy, and finally disappeared (total dose of intravenous TNF alpha, 785,000 JRU). The regression of tumor paralleled the neurologic improvement. He has had no signs of recurrence for 2 years. The present experience indicates that at least a certain population of malignant gliomas can be successfully treated by a systemic administration of TNF alpha without a major adverse effect.

Brain↗

PubMed1994

Elevation of plasma nitric oxide end products during focal cerebral ischemia and reperfusion in the rat.

We investigated the alterations in the stable end products of nitric oxide, i.e., nitrate and nitrite, in the plasma during and after rat focal cerebral ischemia by an automated procedure based on the Griess reaction. At 2 h of middle cerebral artery (MCA) occlusion, plasma nitrate/nitrite levels were significantly higher (53 +/- 8 microM, mean +/- SD, n = 5, p < 0.05) than in rats with sham operation (36 +/- 9 microM, n = 5), and were mildly elevated at 4 h of MCA occlusion (42 +/- 9 microM, n = 5, n.s.). At 30 min of reperfusion after 2 h of MCA occlusion, plasma nitrate/nitrite levels were more markedly elevated (72 +/- 7 microM, n = 5, p < 0.01 vs. sham operation), but were moderately elevated at 2 h of reperfusion after 2 h of MCA occlusion (61 +/- 10 microM, n = 5, p < 0.05). Plasma nitrite levels were not changed during these experimental periods. Administration of 20 mg/kg of NG-nitro-L-arginine methyl ester (L-NAME) significantly decreased plasma nitrate/nitrite as well as nitrite at 30 min of reperfusion after 2 h of MCA occlusion (n = 5), but 2 mg/kg of L-NAME did not (n = 3). The effect of 20 mg/kg of L-NAME on plasma nitric oxide end products was reversed by the simultaneous administration of 200 mg/kg of L-arginine (n = 3), but not D-arginine (n = 3). The present study suggests that the L-arginine-nitric oxide pathway is activated during acute cerebral ischemia and reperfusion.

Animals↗

PubMed1994

[A case of epileptic laughter associated with temporal epidermoid cyst: surgical treatment combined with subdural grid electrode study].

A case of epileptic laughter associated with deep right temporal epidermoid cyst is reported. Interictal EEG with subdural grid electrodes demonstrated multifocal spike discharges in the right temporal lobe. Ictal EEG localized the epileptogenic foci at the base of the anterior medial temporal lobe. After standard temporal lobectomy, the tumor was completely removed. The patient is free from seizures postoperatively.

Brain Diseases↗