Biomedical subjects

T Machida

Publications and source records attributed to T Machida.

382 records · Page 22Linked to original sources

PubMedDate not supplied

Hemodynamics in and around the ischemic focus: a local angiographic study via catheterization to the middle cerebral artery of the cat.

Local hemodynamics in and around the ischemic focus following middle cerebral artery occlusion (MCA) were investigated on angiography by direct infusion of contrast material into the MCA. In anesthetized cats, a catheter was introduced just distal to the site of MCA occlusion through the transorbital approach. MCA stump pressure following occlusion was approximately 20 mmHg. Solute infusion with hydrostatic pressure exceeding stump pressure by approximately 20 mmHg was found to be sufficient to perfuse the entire territory of the MCA. Serial angiography revealed that cortical MCA branches were fully opacified first, and within 10 seconds disappeared centrifugally from the penumbral area. When vessels were occluded together with the internal carotid artery and anterior cerebral artery, backflow was delayed such that the contrast material remained longer within the ischemic focus. This new technique provides a sound basis not only for investigating local hemodynamics but also for direct pharmacological manipulation of the ischemic vessels and brain tissues.

Animals↗

PubMedDate not supplied

MRI findings of multiple malignant gliomas: differentiation from multiple metastatic brain tumors.

Multiple malignant gliomas are relatively uncommon, but are sometimes difficult to differentiate from multiple metastatic brain tumors. We analyzed the MR findings of four cases of multiple gliomas, comparing them with 12 cases of multiple metastatic brain tumors. All tumors were pathologically proven by surgical operation or autopsy. Gliomas were located in the deep white matter of the cerebrum, with none found in the posterior fossa. Tumors were relatively large, and irregular, thick, ring-like enhancement was noted after the administration of Gd-DTPA. Intratumoral hemorrhage was noted in only one case. High signal intensity on T2WI around the tumor suggested that edema was greater and more extensive than in metastatic tumors and was seen even in the corpus callosum. One autopsied case that showed this high intensity presented not only edema but also tumor infiltration. Metastatic tumors were located mainly in the corticomedullary junction of the brain. They were relatively small, and eight of 12 tumors showed, nodular or smooth ring-like enhancement. Intratumoral hemorrhage was noted in four cases. Edema was noted mainly around the tumor. We conclude that differential diagnosis between gliomas and metastases is possible to some extent by MRI.

Adult↗

PubMedDate not supplied

Significant risk factors of recurrence in muscularis proprial carcinoma of the stomach.

BACKGROUND/AIMS: The aim of this study is to elucidate significant risk factors of recurrence in muscularis proprial gastric cancer (MPGC). METHODOLOGY: Seventy-three patients who underwent curative gastrectomy for MPGC were divided into 14 patients with postoperative recurrence (Group 1) and 59 patients without recurrence (Group 2). A retrospective study of Group 1 compared the clinicopathological features with Group 2. RESULTS: There were no significant differences of age, gender and operative method including frequency of lymph node dissection between Group 1 and Group 2. Although tumor size, gastric location and histological type did not significantly differ between the two groups, the rate of Borrman type in Group 1 (71.4%) was significantly higher than in Group 2 (42.4%). Significant risk factors of recurrence in pathological findings were the presence of secondary lymph node metastasis or more, lymphatic and venous involvement. Median survival in Group 1 (28.8 months) was significantly worse than in Group 2 (59.0 months). The 1-year, 3-year, and 5-year survival rates between Group 1 versus Group 2 were 71.4% versus 98.3% (p<0.01), 28.6% versus 96.7% (p<0.01), and 7. 1% versus 95.0 (p<0.01), respectively. CONCLUSIONS: Prognosis of the postoperative recurrence in MPGC was very poor. More careful prophylactic treatment against recurrence of MPGC should therefore, be prescribed in patients with the aforementioned risk factors of recurrence.

Aged↗

PubMedDate not supplied

3D-CT angiography of cerebral arteriovenous malformations.

We studied 76 patients with cerebral arteriovenous malformations (AVMs) using dynamic-CT with intravenous injection of contrast material and reconstructed three-dimensional images (3D-CT angiography). All patients received stereotactic radiotherapy (gamma-knife). We compared 3D-CT angiography with conventional angiography to determine the usefulness of this technique. 3D-CT angiography could be performed in conjunction with usual axial high-resolution CT without any additional scanning time and within 10-30 minutes for the overall study. Most niduses and drainers of AVMs were clearly visualized by 3D-CT angiography. 3D-reconstruction was very helpful in demonstrating the niduses, drainers, and three-dimensional structure of AVMs. Demonstrations of feeders were not remarkable. Dynamic CT was very helpful in dose planning for gamma-knife radiosurgery, because gamma-knife angiograms were limited in terms of angles, magnification, and establishing precise localizations using a head frame. 3D-CT added information on trails of drainers and was useful in reducing the volume of irradiation. 3D-CT angiography of cerebral AVMs could be performed routinely, and three-dimensional imaging was helpful in demonstrating the complex anatomy of cerebral AVMs. This technique was very helpful in planning gamma-knife radiosurgery.

Adult↗