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Biomedical subjects

Y Ushio

Publications and source records attributed to Y Ushio.

At least 181 records · Page 10Linked to original sources
PubMed1995

Differential diagnosis of extra-axial intracranial tumours by dynamic spin-echo MRI.

Dynamic MRI was performed on 22 patients with extra-axial intracranial tumours. Serial images were obtained every 30 s for 3 min using a spin-echo sequence (TR 200, TE 15 ms) after rapid injection of Gd-DTPA, 0.1 mmol/kg body weight. The contrast medium enhancement ratio (CER) was correlated with the histology of the tumours. Meningiomas and extra-axial metastases showed a sharp rise, then a gradual decline. Although both had a definite early peak of CER, metastases showed a more rapid decline. Neuromas and extra-axial lymphoma showed a slow, steady increase with no peak within 180 s. This study indicates that the CER is helpful in the differentiation of extra-axial tumours.

Adult↗
PubMed1995

The mechanism of growth-regulation of glioma cells by trapidil.

Trapidil is a PDGF antagonist that can inhibit the proliferation of the PDGF-producing glioma cells, U251MG. As the mechanism of growth-regulation by trapidil remains unclear, we studied its effect on the growth of U251MG cells. We performed a cell cycle analysis and examined the intracellular transduction pathway and oncogene expression in serum-stimulated glioma cells with or without trapidil. After the serum starvation for 3 days, glioma cell proliferation was stimulated by the addition of serum. Cell cycle analysis showed that cell cycle perturbations induced by trapidil included a decreased transition rate from G0-G1 to S phase, suggesting that some metabolic event is required for progress through the G0-G1 phase and that this event is sensitive to trapidil. Internal signal transduction mechanisms are central in the molecular control of cell growth. One such regulator is the protein kinase C(PKC) system and the c-fos gene is likely to be a direct target of intracellular signal transduction pathways. Therefore, we hypothesize that the intracellular PKC activity and c-fos expression of the trapidil-treated cells are suppressed. We posit that trapidil affects the intracellular signal transduction pathway PKC activity and c-fos expression in cells stimulated with serum containing growth factors.

Blotting, Northern↗
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

Central neurocytoma with hemorrhagic onset.

A case of central neurocytoma with spontaneous intraventricular hemorrhage is reported. A 23-year-old man, 2 years after experiencing intraventricular hemorrhage, developed severe headaches. The magnetic resonance image showed a mixed intense mass in the lateral ventricle with associated hydrocephalus. The tumor mass was totally removed. The tumor was histologically diagnosed as central neurocytoma. Review of the computed tomography taken 2 years ago showed not only the hemorrhage but also a mass in the left lateral ventricle. This emphasizes that central neurocytoma should be considered in the differential diagnosis of patients with either intraventricular hemorrhage or hemorrhagic tumor.

Adult↗
PubMed1995

Primary intracranial plasma-cell granuloma: a case report and review of the literature.

BACKGROUND: Plasma-cell granulomas, which are characterized by the non-neoplastic proliferation of plasma cells, are primarily found in the lungs and upper respiratory tracts, and are extremely rare in the central nervous system. METHODS: An intracranial tumor of an 11-year-old boy was evaluated by histologic and radiologic examination. RESULTS: An 11-year-old boy had a 2-month history of mild headache and nausea. A computed tomography scan showed a round, slightly high-density mass surrounded by marked edema in the left frontal lobe. On magnetic resonance imaging (MRI), the mass had a slightly high signal intensity on the T1-weighted image and marked low signal intensity on the T2-weighted image. It was heterogenously enhanced with gadolinium-DTPA. Microscopic examination demonstrated a non-neoplastic mixed cell population with a predominance of plasma cells. Immunohistochemical staining revealed that it was characterized by a polyclonal plasma cell population. CONCLUSION: Our extensive search of the literature indicated this to be the ninth reported case of intracranial plasma cell granulation. The MRI was very useful for evaluating the extent of the intracranial lesions. The tumor was removed surgically and did not recur during a 2-year follow-up with no radiation therapy.

Brain Diseases↗
PubMed1995

Immunocytochemical localization of the striatal enriched protein tyrosine phosphatase in the rat striatum: a light and electron microscopic study with a complementary DNA-generated polyclonal antibody.

The present study concerns the immunocytochemical localization of the striatal enriched protein tyrosine phosphatase in the rat striatum. A novel molecular biology technique allowed us to produce a complementary DNA-generated polyclonal antibody raised against the non-catalytic domain of the striatal enriched protein tyrosine phosphatase, which selectively recognized the striatal enriched protein tyrosine phosphatase protein with 46,000 mol. wt on western blots. Immunocytochemical analysis with the specific antibody revealed strong striatal enriched protein tyrosine phosphatase immunoreactivity in the striatum. Light microscopy showed striatal striatal enriched protein tyrosine phosphatase-immunopositive neurons to be of medium size (mean diameter of 14.4 microns), and to comprise approximately 80% of the total neuronal population in the striatum. These cells had round, triangular or polygonal cell bodies with relatively little cytoplasm. Nerve fibers stained positively for striatal enriched protein tyrosine phosphatase were also present in the globus pallidus and the substantia nigra, and the nigral labeling on the ipsilateral side almost disappeared subsequent to cerebral hemitransection, suggesting these immunolabeled structures to be striatal projections. Double-immunofluorescence analysis demonstrated separate populations of striatal enriched protein tyrosine phosphatase-positive cells and neurons stained for parvalbumin. Also, ultrastructural study showed that the striatal enriched protein tyrosine phosphatase-positive neurons (n = 50) possessed no nuclear indentations or intranuclear inclusions. Thus, most striatal striatal enriched protein tyrosine phosphatase-positive neurons were thought to be of the medium-sized spinous type. At the light microscopic level, stained striatal neurons exhibited striatal enriched protein tyrosine phosphatase immunolabeling in their somata, dendrites and axonal processes, but not in their nuclei. Electron microscopic observation showed strong striatal enriched protein tyrosine phosphatase-immunoreactivity on the inner surface of the plasmalemma, on the outer surfaces of mitochondria and on microtubules, particularly of dendrites. A heavy deposit of immunoreaction product was also present on postsynaptic densities in labeled dendrites, while a light deposit was seen on the synaptic vesicles of nerve terminals. The characteristic distribution profile of striatal enriched protein tyrosine phosphatase suggested that the enzyme may play a role in a variety of functional properties of striatal neurons, especially in postsynaptic signaling processes and in regulation of microtubular functions. On the basis of the present findings, we propose the following conclusions: (i) a protein tyrosine phosphorylation system regulated by striatal enriched protein tyrosine phosphatase is involved in certain specialized cellular processes (e.g. signal transduction cascades) of medium-sized spinous neurons distinct from those of other neuronal subsets in the striatum; (ii) a striatal medium spiny neuron is characterized by its expression of striatal enriched protein tyrosine phosphatase and, therefore, the enzyme is useful for detection of the distinct subset of striatal cells or for tracing their axonal projection fibers in the basal ganglia.

Animals↗
PubMed1995

Glutamate-induced loss of Ca2+/calmodulin-dependent protein kinase II activity in cultured rat hippocampal neurons.

The exposure of cultured rat hippocampal neurons to 500 microM glutamate for 20 min induced a 55% decrease in the total Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) activity. The Ca(2+)-independent activity and autophosphorylation of CaM kinase II decreased to the same extent as the changes observed in total CaM kinase II activity, and these decreases in activities were prevented by pretreatment with MK-801, an N-methyl-D-aspartate (NMDA)-type receptor antagonist, and the removal of extracellular calcium but not by antagonists against other types of glutamate receptors and protease inhibitors. Similarly, the decrease in the CaM kinase II activity was induced by a Ca2+ ionophore, ionomycin. Immunoblot analysis with the anti-CaM kinase II antibody revealed a significant decrease in the amount of the enzyme in the soluble fraction, in contrast with the inverse increase in the insoluble fraction; thus, the translocation was probably induced during treatment of the cells with glutamate. These results suggest that glutamate released during brain ischemia induces a loss of CaM kinase II activity in hippocampal neurons, by stimulation of the NMDA receptor, and that inactivation of the enzyme may possibly be involved in the cascade of the glutamate neurotoxicity following brain ischemia.

Animals↗
PubMed1995

Activation of mitogen-activated protein kinase in cultured rat hippocampal neurons by stimulation of glutamate receptors.

Mitogen-activated protein kinase (MAP kinase) was activated by stimulation of glutamate receptors in cultured rat hippocampal neurons. Ten micromolar glutamate maximally stimulated MAP kinase activity, which peaked during 10 min and decreased to the basal level within 30 min. Experiments using glutamate receptor agonists and antagonists revealed that glutamate stimulated MAP kinase through NMDA and metabotropic glutamate receptors but not through non-NMDA receptors. Glutamate and its receptor agonists had no apparent effect on MAP kinase activation in cultured cortical astrocytes. Addition of calphostin C, a protein kinase C (PKC) inhibitor, or down-regulation of PKC activity partly abolished the stimulatory effect by glutamate, but the MAP kinase activation by treatment with ionomycin, a Ca2+ ionophore, remained intact. Lavendustin A, a tryrosine kinase inhibitor, was without effect. In experiments with 32P-labeled hippocampal neurons, MAP kinase activation by glutamate was associated with phosphorylation of the tyrosine residue located on MAP kinase. However, phosphorylation of Raf-1, the c-raf protooncogene product, was not stimulated by treatment with glutamate. Our observations suggest that MAP kinase activation through glutamate receptors in hippocampal neurons is mediated by both the PKC-dependent and the Ca(2+)-dependent pathways and that the activation of Raf-1 is not involved.

Animals↗
PubMed1995

Hemifacial spasm: three-dimensional MR images in the evaluation of neurovascular compression.

PURPOSE: To assess the diagnostic accuracy of three-dimensional (3D) magnetic resonance (MR) images in the preoperative evaluation of hemifacial spasm. MATERIALS AND METHODS: In 27 patients with surgically confirmed hemifacial spasm, the axial source images from 3D time-of-flight MR angiography were evaluated for 27 symptomatic sides and 26 asymptomatic sides by three observers in a blinded manner for neurovascular compression and identification of compressive vessels. RESULTS: Sensitivity was 95% and specificity was 77%. Vascular compression on the symptomatic sides could be identified retrospectively in all 27 patients. On the asymptomatic sides, vascular compression could be excluded retrospectively in all but one patient. In the blinded study, as the mean value of three observers, the vertebral artery and posterior inferior cerebellar artery could be identified correctly in seven and 7.7 of seven and nine patients, respectively, whereas the compressive anterior inferior cerebellar artery was identified correctly in 7.7 of 16 patients. CONCLUSION: Three-dimensional MR images have a high diagnostic accuracy and are useful in the preoperative evaluation of hemifacial spasm.

Adult↗
PubMed1995

Treatment of intracranial nongerminomatous malignant germ cell tumors producing alpha-fetoprotein.

We treated 10 patients with intracranial nongerminomatous malignant germ cell tumors producing alpha-fetoprotein between 1969 and 1992. Two patients were treated with radiotherapy (RT) only (RT group), and three were treated with RT and cisplatin plus vinblastine plus bleomycin therapy with or without surgery (cisplatin plus vinblastine plus bleomycin group). The most recently treated five patients received cisplatin plus etoposide (PE) therapy with or without RT and/or surgery (PE group). The level of alpha-fetoprotein in serum was elevated in all 10 patients. In the PE group, PE therapy consisted of cisplatin (20 mg/m2) and etoposide (60 mg/m2) daily for 5 days (one course) given two or three times at 4-week intervals and then once every 4 months; the patients received three to six courses (mean, 4.2 courses). In the RT group (n = 2), one patient died 3 months after diagnosis and the other died at 12 months. In the cisplatin plus vinblastine plus bleomycin group (n = 3), complete remission was obtained in one patient, but the other two patients died 12 and 24 months after diagnosis. In contrast, in the PE group (n = 5), complete remission was obtained in all patients who are all currently alive without recurrence, at 35 to 71 months (average, 53.6 mo) after diagnosis. The results indicate that multidisciplinary treatment including combination chemotherapy with cisplatin and etoposide with or without surgery and/or RT is highly effective in the treatment of patients with alpha-fetoprotein-producing intracranial nongerminomatous malignant germ cell tumor.

Adolescent↗
PubMed1995

Correlation between magnetic resonance images and histology in meningiomas: T2-weighted images indicate collagen contents in tissues.

The magnetic resonance imaging appearance of 40 surgically confirmed intracranial meningiomas was reviewed to correlate signal intensity on T2-weighted images with histological subtypes of meningioma. A moderate variation of signal intensity was found within a given histological subtype. The mean signal intensity scores on T2-weighted images of the fibrous type of meningioma were significantly lower than those of the other types, and were correlated with the collagen content. The signal intensity of meningiomas on T2-weighted images crudely predicts the histological type. Tumors significantly hypointense compared to the cortex are composed primarily of fibrous elements.

Brain↗
PubMed1995

Kernohan's notch in chronic subdural hematoma: findings on magnetic resonance imaging.

A 69-year-old man presented with mild left-sided hemiparesis of 2 years' duration. A computerized tomography scan revealed a left-sided chronic subdural hematoma and a midline shift to the right. Magnetic resonance (MR) imaging obtained on admission to the hospital also disclosed a deformity of the right crus cerebri. After drainage and irrigation of the hematoma through a single burr hole, the left hemiparesis improved significantly. Magnetic resonance imaging performed 9 days after the operation revealed that the size of the subdural hematoma had diminished and the deformity of the crus cerebri had improved markedly. Kernohan's notch, caused by a supratentorial mass and producing ipsilateral hemiparesis or hemiplegia, is rarely demonstrated radiographically. This may be the first reported case in which Kernohan's notch in chronic subdural hematoma has been demonstrated on MR imaging.

Aged↗
PubMed1995

Thrombosed growing giant aneurysms of the vertebral artery: growth mechanism and management.

Results in three patients with thrombosed giant aneurysms of the vertebral artery are reported. Each of the aneurysms presented as a mass lesion. On postcontrast computerized tomography and magnetic resonance imaging, each aneurysm demonstrated a patent lumen and intrathrombotic vascular channels. Two patients died and were autopsied, and the other patient was successfully treated. Pathological examination revealed that the aneurysms had staged clots, an open lumen, intrathrombotic channels with endothelial lining, and aneurysmal walls with intimal thickening. The authors suggest that the development of the intrathrombotic capillary channels may be an important factor in the growth of thrombosed giant aneurysm of the vertebral artery. Trapping of the aneurysm followed by aneurysmectomy appears to be the best treatment for this type of aneurysm.

Adult↗
PubMed1995

Expression of monocyte chemoattractant protein-1 in meningioma.

Monocyte chemoattractant protein-1 (MCP-1), purified from glioma cell line (U-105MG) culture fluid, attracts monocytes but not neutrophils. Macrophage accumulation is one of the pathological features of meningioma. To investigate the mechanism of macrophage infiltration into meningioma, the expression and localization of MCP-1 in 16 cases of meningioma were studied using Northern blot analysis and immunohistochemistry. Seven of 16 meningiomas expressed MCP-1 messenger ribonucleic acid and protein, and some degree of macrophage infiltration was seen in all 16 meningiomas. There was a relationship between MCP-1 expression and the degree of macrophage infiltration; MCP-1 was strongly expressed in meningiomas with a high degree of macrophage infiltration. Sometimes the meningioma was accompanied by perifocal edema; a correlation between macrophage infiltration into brain tumors and perifocal edema has already been reported. It was found that the degree of MCP-1 expression is not correlated with the extent of perifocal edema. The authors' findings suggest that MCP-1 plays an important role in macrophage infiltration into meningioma.

Adult↗
PubMed1995

Immunohistochemical expression of inducible nitric oxide synthase (iNOS) in reversible endotoxic shock studied by a novel monoclonal antibody against rat iNOS.

An antirat monoclonal antibody (mAb) against inducible nitric oxide synthase (iNOS), ANOS11, was used for immunohistochemistry to examine the expression of iNOS in various organs and tissues of adult rats in experimental endotoxic shock induced by lipopolysaccharide (LPS) injection. The phenotype of iNOS-expressed cells was also examined immunohistochemically using various mAbs. In control rats, very few cells were positive for ANOS11 except in the thymus. After intravenous injection of LPS, the number of iNOS-positive cells increased rapidly in almost all organs, except the thymus and brain, peaked 6 h after the injection, and decreased slowly. Of the numerous inflammatory cells that infiltrated the lungs, liver, and spleen after LPS injection, many were positive for ANOS11. Besides inflammatory cells, hepatocytes and endothelial cells of the aorta were also positive for ANOS11 but only around 6 h after injection. The cellular composition of iNOS-positive infiltrated cells changed along with the progression of endotoxic shock. At 4 to 6 h after injection, most iNOS-positive cells were considered polymorphonuclear leukocytes judging by their positive reactivity to OX42 and their nuclear morphology. The population of iNOS-positive macrophages positive for ED1 or ED2 increased with time. After 24 h, many iNOS-positive macrophages were found around the focal necrosis in the liver and spleen. These results indicate that the expression of iNOS in neutrophils, endothelial cells, and hepatocytes precedes that of macrophages in experimental endotoxic shock. The expression of iNOS in various cells and organs is closely associated with the progress and pathological changes of endotoxic shock.

Amino Acid Oxidoreductases↗
PubMed1995

Immunostaining for calcineurin, a Ca2+/calmodulin-regulated protein phosphatase, in the diagnostic tumor pathology.

The present immunochemical study concerns the distribution of calcineurin (CaN), a Ca2+/calmodulin-regulated protein phosphatase, in the nervous and neuroendocrine systems of mammals, and discloses the CaN-immunostaining results of human neoplasms. CaN immunoreactivity (ir) was present throughout the nervous system with a marked regional variation in strength of the staining intensity. Light microscopic observations showed that CaN-ir was localized in neurons, but was not detected in non-neuronal cells including astrocytes. Ultrastructural study also revealed that CaN-ir was present only in neuronal elements such as somata, dendrites including postsynaptic densities and spines, and nerve terminals. CaN-ir was also detected in neuroendocrine cells of some endocrine tissues including the pineal gland, pituitary gland, adrenal grand, pancreas and thyroid gland. Immunostaining results of 107 surgical specimens of human neoplasms, including 9 cases of peripheral tumors, disclosed that CaN-immunopositive tumor cells were found to be present in the neuronal tumors including neuroblastomas, ganglioglioma, ganglioneuroma, ganglioneuroblastoma, retinoblastomas, medulloblastomas and central neurocytomas. Also, some neuroendocrine tumors, such as pineocytomas, olfactory neuroblastomas and paragangliomas, specifically reacted for anti-CaN antibody. On the basis of these immunochemical findings, we have proposed that CaN can be a marker protein for detection of neuronal and neuroendocrine tumor cells in the diagnostic pathology of human neoplasms.

Animals↗
PubMed1995

Expression of osteopontin in human glioma. Its correlation with the malignancy.

BACKGROUND: Osteopontin (OPN) is a phosphorylated glycoprotein that contains a functional Gly-Arg-Gly-Asp-Ser (GRGDS) cell-binding sequence. It is reported that the expression of OPN is increased in a number of transformed cell lines. This study demonstrates the expression of OPN in human glioma representative of brain tumors. EXPERIMENTAL DESIGN: The expression of OPN in human gliomas was determined with: (a) Northern blot analysis; (b) Southern blot analysis; (c) Immunofluorescent cytochemistry; (d) Western blot analysis; (e) Cloning and sequencing of complementary DNAs (cDNAS); (f) Immunohistochemistry. RESULTS: OPN mRNA was detected in all glioma cell lines examined, and Southern blot analysis showed that OPN DNA most likely exists as a single copy gene in these cell lines. Immunofluorescent cytochemistry showed strong staining mainly in the cytoplasm. These cell lines produced two major forms of OPN protein migrating at 53 and 47 kilodaltons, and two minor forms at 38 and 31 kilodaltons on 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels. We also isolated and sequenced three types of splice variants in OPN from human glioma cell lines through polymerase chain reaction. In addition, Northern blot analysis was carried out on RNA from human astrocytoma tissues of various malignancy grades. Expression of OPN mRNA was high in malignant astrocytomas, but low in benign astrocytomas and non-neoplastic tissue. Immunohistochemistry also showed strong staining in malignant astrocytomas and slight staining in benign astrocytomas. CONCLUSIONS: These findings indicate that OPN mRNA and proteins are expressed in human glioma cells, and that the extent of OPN expression may correlate with the malignancy grade of gliomas.

Alternative Splicing↗