Biomedical subjects

Y Ushio

Publications and source records attributed to Y Ushio.

At least 73 records · Page 4Linked to original sources

PubMed2000

Radiation-induced cerebrovasculopathy of the distal middle cerebral artery and distal posterior cerebral artery--case report.

A 15-year-old girl underwent partial removal of a pituitary adenoma followed by local irradiation of the brain with a total of 70 Gy through two lateral opposing ports. Twenty years later, she experienced frequent transient ischemic attacks with left sensory disturbance. Cerebral angiography revealed stenoses of the right distal middle cerebral artery (MCA) and the right distal posterior cerebral artery without net-like vessels. There was a severe decrease of vasoreactivity in the right hemisphere. Right superficial temporal artery (STA)-MCA anastomosis was performed. Her neurological deficits were resolved and perfusion reserve capacity had markedly improved 6 months later. We recommend STA-MCA anastomosis in such cases.

Adolescent↗

PubMed2000

Incidence and clinical features of asymptomatic meningiomas.

OBJECT: The increased use of computerized tomography (CT) and magnetic resonance (MR) technology has led to an increase in the detection of asymptomatic meningiomas, although the surgical indication for these tumors remains undetermined. The authors investigated the incidence of asymptomatic meningiomas and their clinical features. METHODS: An epidemiological survey was conducted of primary intracranial tumors diagnosed in Kumamoto Prefecture between 1989 and 1996. Follow-up neuroradiological imaging and clinical studies for asymptomatic meningiomas were performed. Primary intracranial tumors were diagnosed in 1,563 residents. Of these lesions, 504 (32.2%) were meningiomas, and of these meningiomas 196 (38.9%) were asymptomatic. The incidence of asymptomatic meningiomas was significantly higher in individuals older than 70 years of age. Furthermore, the incidence of asymptomatic meningiomas was significantly higher in female than in male patients. Of the asymptomatic meningiomas in 196 patients, 87 (44.4%) were surgically removed, whereas 109 (55.6%) were treated conservatively. Of these conservatively treated patients, 63 received follow-up care for more than 1 year. In 20 of these 63 cases, the tumors increased in size over the 27.8-month average follow-up period (range 12-87 months), whereas in the other 43 cases, the tumor size did not increase during a 36.6-month average follow-up period (range 12-96 months). There was no significant difference with respect to age, tumor size, and male/female ratio between the patient group in which the tumor size increased and the group in which it did not increase during the follow-up period. Asymptomatic meningiomas that evidenced calcification on CT scans and/or hypointensity on T2-weighted MR images appear to have a slower growth rate. CONCLUSIONS: Among patients older than age 70 years who underwent operation for asymptomatic meningioma, the neurological morbidity rate was 23.3%; it was 3.5% among younger patients. This indicates that the advisability of surgery in elderly patients with asymptomatic meningiomas must be considered very carefully.

Adult↗

PubMed2000

Histopathological study of venous aneurysms in patients with dural arteriovenous fistulas.

OBJECT: Of all intracranial dural arteriovenous fistulas (DAVFs), those with cortical venous drainage associated with cortical venous ectasia or varices are predisposed to an aggressive course and produce progressive neurological symptoms or hemorrhages. The authors undertook a histological examination of venous aneurysms and arterialized veins in the proximity of these aneurysms that had been surgically removed in patients with DAVFs. METHODS: Surgical specimens were obtained in eight patients. The excised venous aneurysms and the arterialized veins in their proximity were stained using hematoxylin and eosin, van Gieson's elastic, and Masson's trichrome stain. Immunostaining was also performed for alpha smooth-muscle actin, desmin, and factor VIII antigen. Five of the patients had presented with venous hypertension, and three had intracranial hemorrhages. The arterialized vein obtained in the proximity of the venous aneurysm exhibited local irregular intimal thickening; the internal elastic lamina (IEL) was grossly preserved. All venous aneurysms in patients with venous hypertension manifested medial thickening and local intimal thickening with loss of IEL; the thickness of the wall was relatively uniform. In contrast, the wall thickness of venous aneurysms in patients with hemorrhage was extremely irregular and there was no clear delineation between the media and the intima. In media with complete disappearance of IEL, there was scant muscle tissue. CONCLUSIONS: Degenerative changes in venous aneurysms in patients with hemorrhage were much greater than in patients with venous hypertension, possibly because hemorrhages result from a more complicated interplay of anatomical, hemodynamic, and degenerative factors.

Aged↗

PubMed2000

Suppression of the tissue factor-dependent coagulation cascade: a contributing factor for the development of intratumoral hemorrhage in glioblastoma.

To clarify factors that may contribute to the development of intratumoral hemorrhage, we analyzed the expression of tissue factor (TF), an initiator of the extrinsic coagulation pathway, and of tissue factor pathway inhibitor (TFPI) in glioblastomas with or without massive intratumoral hematoma. Among 196 glioma cases reviewed, there were 13 with macroscopic intratumoral hemorrhage. We focused on the glioblastomas and used immunoblot- and immunohistochemical methods to compare the expression of TF and TFPI in 9 glioblastomas with macroscopic hematoma and 30 glioblastomas without macroscopic hemorrhage. Although TF was expressed in most glioblastomas irrespective of the presence or absence of macroscopic hemorrhage, the staining patterns differed significantly: TF-positive glioma cells were diffusely present in the non-hemorrhage group; in the group with hemorrhage, positive cells, primarily macrophages, were scattered throughout the tissue examined. The expression of TFPI was significantly higher in the group with than in the group without hemorrhage. Our results suggest that local suppression of the TF-dependent coagulation cascade is a contributing factor that permits the occurrence of intratumoral hemorrhage.

Adult↗

PubMed2000

Gene delivery with optimized electroporation parameters shows potential for treatment of gliomas.

Electroporation, a standard laboratory method of introducing exogenous molecules into cells, has been gaining importance as a very effective non-viral physical technique of gene delivery. In this study, we have used subcutaneous model of the C6 rat glioma cells and established an optimal condition to obtain very high gene expression in tumor tissues using both reporter and functional genes. Tumors grown on the flanks of Wistar rats are exposed and directly injected with plasmid DNA having the constructs of luciferase, green fluorescent protein and, the fragment of the diphtheria toxin, DT-A. The tumors are then subjected to square wave pulses from an electroporator. Gene expression is found to be several orders of magnitude higher when the tumors are pulsed with the optimized electrical parameters compared to the controls. For luciferase, the enhancement is approximately 135-fold, for the green fluorescent protein, gene expression is seen over a wide area within the sections examined, as contrast to a few punctate dots in the control specimens, and finally, DT-A shows massive death in the tumor tissue. A special circular array of six needles through which pulses are delivered with rotating electric field is found to be highly efficient in transferring genes inside the tumor. Direct injection of plasmid DNA followed by electroporation allows very high in vivo gene transfer and its subsequent expression into tumor tissues. This method may be applicable to any solid tumor.

Animals↗

PubMed2000

Evaluation of dural sinus invasion and extension of extra-axial intracranial tumors. The advantages of a high-resolution postcontrast 3-D gradient-echo technique.

OBJECTIVE: To assess the usefulness of a postcontrast 3-D Fourier transform (3DFT) gradient-echo (GRE) technique in dural sinus invasion and extension of extraaxial intracranial tumors in comparison with a conventional spin-echo (SE) technique. MATERIAL AND METHODS: Fourteen consecutive patients with 15 extra-axial tumors in contiguity with the dural sinus, including 14 meningiomas and 1 adenoid cystic carcinoma, underwent postcontrast T1-weighted SE and GRE MR studies. Detectability of dural sinus invasion and extension was evaluated using two sequences by two neuroradiologists in a blinded manner and compared with surgical results. Quantitative analysis was also performed to calculate the contrast-to-noise ratio (CNR) between lesion and dural sinus on SE and GRE images. The data were analyzed statistically using a matched paired t-test. RESULTS: In the qualitative evaluation, the detectability of dural sinus invasion in 3DFT-GRE images was superior to that using SE images. The mean CNR for all lesions was 3.86 on SE images and 5.63 on 3DFT-GRE images (p = 0.03). CONCLUSION: For evaluation of dural sinus invasion and the extension of extra-axial tumors, postcontrast 3DFT-GRE MR images were superior to conventional SE images.

Adult↗

PubMed2000

Cerebral function after aortic surgery using retrograde cerebral perfusion: report of three cases.

INTRODUCTION: The neurological analysis undertaken on three cases of aortic aneurysm treated surgically using retrograde cerebral perfusion (RCP) are reported herein. This is the first detailed analysis of postoperative neurological studies in such cases. METHODS: The oxygenation state of cerebral Hb and cytochrome aa3 levels were monitored by near-infrared spectroscopy (NIR) during RCP. Postoperative neurological scoring, computed tomography (CT), magnetic resonance imaging (MRI), and monitoring of local cerebral blood flow (LCBF) quantatively by N-isopropyl-p-[123I] iodoamphetamine (IMP) single-photon emission computed tomography (SPECT) were performed for an extended follow-up period after surgery. RESULTS: The T2WI of MRI findings which consisted of many spotty high intensity areas in the striatum, cerebellum and hippocampus, may reflect the postoperative severe consciousness and mental disturbances (2-4 weeks). However, in all cases the neurological deficit gradually improved until they returned to their normal preoperative states. The improvement of LCBF correlated well with neurological recovery. CONCLUSION: The conditions of the conventional method of RCP must be improved to prevent transient severe consciousness and mental disturbances which occur after the operation in relationship with the appearance of the high intensity area on the MRI T2WI.

Adult↗

PubMed2000

Posttherapeutic intraaxial brain tumor: the value of perfusion-sensitive contrast-enhanced MR imaging for differentiating tumor recurrence from nonneoplastic contrast-enhancing tissue.

BACKGROUND AND PURPOSE: Differentiation of tumor recurrence from treatment-related changes may be difficult with conventional MR imaging when newly enhancing lesions appear. Our aim was to determine the value of perfusion-sensitive contrast-enhanced MR imaging for differentiating recurrent neoplasm from nonneoplastic contrast-enhancing tissue. METHODS: Twenty patients in whom new enhancing lesions developed within irradiated regions were examined prospectively with perfusion-sensitive contrast-enhanced MR imaging. Twelve of them also underwent thallous chloride Tl 201 single-photon emission tomography (201Tl-SPECT). Normalized relative cerebral blood volume (rCBV) ratios and thallium indexes were evaluated to determine whether the new enhancing lesions were recurrent or not. Five instances of tumor recurrence and one of radiation necrosis were verified histologically; in the others, tumor recurrence was distinguished by lesions that progressively increased in size on serial MR examinations over at least 5 months, and nonneoplastic contrast-enhancing tissue was distinguished by lesions that disappeared or decreased in size on serial MR studies over at least 9 months. RESULTS: When normalized rCBV ratios were higher than 2.6 or lower than 0.6, enhancing lesions were either recurrent (n = 5) or nonneoplastic contrast-enhancing tissue (n = 3), respectively. All nonneoplastic contrast-enhancing tissue had a low thallium index, whereas three of four recurrent lesions had a high index. CONCLUSION: An enhancing lesion with a normalized rCBV ratio higher than 2.6 or lower than 0.6 may suggest tumor recurrence or nonneoplastic contrast-enhancing tissue, respectively. In these cases, further examination with 201Tl-SPECT may not be necessary. However, when the normalized rCBV ratio is between 0.6 and 2.6, 201Tl-SPECT may be useful in making the differentiation.

Adolescent↗

PubMed2000

Spinal seeding of anaplastic ependymoma mimicking fungal meningitis. A case report and review of the literature.

BACKGROUND: The spinal seeding from brain tumors sometimes mimicks fungal meningitis on examination of cerebrospinal fluid. METHODS AND RESULTS: A 19-year-old woman gradually developed increased intracranial hypertension. MRI identified a mass in the right parieto-occipital area. It was totally removed and histologically diagnosed as an anaplastic ependymoma. Radiation- and chemotherapy were administered postoperatively. The patient reported low back pain 5 months after the surgical treatment. MRI disclosed neither spinal dissemination nor tumor recurrence at the primary site. Lumbar puncture was performed and the cerebrospinal fluid (CSF) was found to have an extremely low glucose level (5 mg/dl); no tumor cells were identified. Blood samples were obtained and a relative increase of WBC and CRP was noted. A slight degree of inflammation and low-grade fever were recorded. A tentative diagnosis of fungal meningitis was made and anti-fungal therapy was administered transventricularly and transvenously. However, her neurological condition continued to deteriorate gradually. Sequential CSF studies showed that the glucose level remained extremely low, it even decreased to 0 mg/dl Eight months after the surgical treatment, MRI with Gd-DTPA revealed marked subarachnoid enhancement in both intracranial and spinal areas. An open biopsy was performed and a histological diagnosis of intracranial and spinal seeding of the anaplastic ependymoma was returned. CONCLUSIONS: We report a patient with intracranial and spinal seeding of an anaplastic ependymoma that mimicked fungal meningitis. We discuss the difficulty of obtaining a differential diagnosis in this case and describe the mechanism of the decreased CSF glucose level.

Adult↗

PubMed2000