Biomedical subjects

T Machida

Publications and source records attributed to T Machida.

375 records · Page 21Linked to original sources

PubMedDate not supplied

CT and MR imaging of fatty tumors of the liver.

The presence of fat in hepatic masses narrows the range of differential diagnoses down to hepatic angiomyolipoma, lipoma, adenoma, hepatoma, metastatic fatty tumors of the liver, focal fatty infiltration of the liver, and extrahepatic fatty masses such as intraperitoneal implants from malignant teratomas, and packed omentum. We report six hepatic tumors containing fat (lipoma, hepatocellular carcinoma, and calcified mass with fat-fluid level) with CT and magnetic resonance (MR) imaging. The distribution of fat was diffuse in the lipomas and some hepatocellular carcinomas and localized in other hepatocellular carcinomas and fat-fluid masses. The density ranged from - 100 to 0 HU. High intensity areas on both T1- and T2-weighted MR images corresponded to the hypodense areas on CT.

Adult↗

PubMedDate not supplied

Measurement of the mechanical properties of the tympanic membrane with a microtension tester.

The mechanical properties of guinea pig and human tympanic membranes were measured by a microtension tester newly developed by us. Guinea pig tympanic membranes were tested under various conditions. When the tensile rate was 4.17 x 10(-4) m.sec-1 fresh specimens were 8.8 times stronger for a tension applied parallel to the radial fibres than for that applied at a right angle to them. No difference in tensile strength was seen when the tension was applied at a right angle to the radial fibres. When the tensile direction was parallel to the radial fibres, the posterior part was stronger than the anterior part. Two human tympanic membranes were measured under formalin fixation. The measured values were calculated into those of the fresh specimens based on the results of the guinea pig material. The adjusted values for fresh human specimens were 2.56 kgf.mm-2 at a right angle to the radial fibres and 3.28 kgf.mm-2 parallel to them. Applying the thin cylinder and shell theory, the breakage pressure of the human tympanic membrane was calculated to be 1.02-22.4 atmospheric pressure.

Animals↗

PubMedDate not supplied

Post-operative chemotherapy in non-curative gastrectomy for advanced gastric cancer.

BACKGROUND/AIMS: The definitive effects of post-operative chemotherapy for prolonging survival in patients with non-curative gastrectomy for advanced gastric cancer have not been established. METHODOLOGY: Eighty-three patients with advanced gastric cancer who underwent non-curative gastrectomy were divided into 49 patients with post-operative chemotherapy (chemotherapy group) and 34 patients without post-operative chemotherapy (control group). Chemotherapy regimens were as follows: oral 5-fluorouracil (5-FU) alone (n = 22), intravenous mitomycin (MMC) plus 5-FU (n = 20), intravenous methotrexate (MTX) plus 5-FU (n = 3), intravenous cisplatin plus 5-FU (n = 2), and hepatic arterial infusion of 5-FU plus oral 5-FU (n = 2). No prior chemotherapy or radiation therapy was given. RESULTS: Although the age in the control group (mean: 71.9 years) was significantly older than in the chemotherapy group (mean: 66.1 years), there were no significant differences in the other clinical and pathological background data between the two groups. The 1-year survival rate in the chemotherapy group (71.4%) was significantly higher than in the control group (50.0%). However, the 3-year and 5-year survival rates did not significantly differ in the chemotherapy group versus the control group, 30.6% vs. 32.4% and 24.5% vs. 32.4%, respectively. Although a significant difference did not exist between the two groups, median survival after operation in the chemotherapy group (20.5 months) was longer than that in the control group (16.2 months). Furthermore, median survival of patients with peritoneal dissemination in the chemotherapy group (16.4 months) was significantly longer than that in the control group (7.7 months). CONCLUSIONS: Post-operative chemotherapy may contribute to prolonged survival in patients with non-curable advanced gastric cancer, even when patients had peritoneal dissemination. However, the long-term survival rate was not improved by post-operative chemotherapy. More aggressive chemotherapy may be needed to improve the long-term prognosis for such patients.

Adenocarcinoma↗

PubMedDate not supplied

Efficacy of extended lymphadenectomy in the noncurative gastrectomy for advanced gastric cancer.

BACKGROUND/AIMS: We retrospectively analyzed clinicopathologic data on 83 patients with advanced gastric cancer who underwent noncurative gastrectomy, with respect to the relation between the extent of lymphadenectomy and survival benefit. METHODOLOGY: These 83 patients were divided into 44 patients with limited or simple lymph node dissection (D0 in 14 and D1 in 30: Group A) and 39 patients with extended lymph node dissection (D2: Group B). RESULTS: The 1-year survival rate in Group B (82.1%) was significantly higher than in Group A (49.0%). However, the 3-year and 5-year survival rates did not significantly differ between Group A versus Group B, 39.7% versus 25.7% and 39.7% versus 20.5%, respectively. Median survival time after surgery with and without distant metastasis in Group B (21.5 months) was longer than in Group A (16.4 months), although not significant. CONCLUSIONS: While gastrectomy with extended lymphadenectomy did not contribute to improve long-term survival in patients with noncurable advanced gastric cancer, the utility of extended lymph node dissections may be relevant to improved locoregional control, at least in the prognosis within 1 year after surgery. Not only extended lymphadenectomy but also aggressive chemotherapy may be needed to improve the long-term survival for such patients.

Aged↗

PubMedDate not supplied

Surgical outcome in cirrhotic patients with hepatitis C-related hepatocellular carcinoma.

BACKGROUND/AIMS: The aim of this study was to clarify the surgical outcome in cirrhotic patients with hepatitis C-related hepatocellular carcinoma (HCC). METHODOLOGY: The surgical outcome of 26 HCVAb-positive cirrhotic patients with hepatitis C antibody (the C-related HCC group) and 18 HCVAb-negative cirrhotic patients with (the non-C-related HCC group) undergoing hepatectomy for HCC were compared. The C-related HCC group was HCVAb[+], HBsAg[-] for hepatitis B surface antigen in 25 patients and HCVAb[+], HBsAg[+] in 1, and the non C-related HCC group was HCVAb[-], HBsAg[+] in 15 and HCVAb[-], HBsAg[-] in 3. RESULTS: Preoperative aspartate and alanine aminotransferase in the C-related HCC group were significantly (P < 0.01) higher than in the non-C-related HCC group. There were no significant differences in the operative method, intraoperative blood loss and weight of resected liver or pathological data between the 2 groups. In the recurrence pattern, the incidence of multicentric occurrence in the C-related HCC group (53.3%) was significantly (P < 0.05) higher than in the non-C-related HCC group (7.7%). The mortality rate in both groups was 0% and no operative death was encountered. The crude survival and disease-free survival rates at 3 years were similar: 80.8% and 57.7% in the C-related HCC group and 77.8% and 55.6% in the non-C-related HCC group, respectively. CONCLUSIONS: Although surgically treated cirrhotic patients with C-related HCC showed worse preoperative hepatitis status and a higher incidence of recurrence due to multicentricity compared with non-C-related HCC, the mortality and prognosis of patients with C-related HCC did not differ from that of non-C-related HCC. The indication of hepatic resection and consideration for the high incidence of postoperative multicentric occurrence in the patients with C-related HCC should therefore be more careful than in patients with non-C-related HCC.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Cerebral aneurysms: detection and delineation using 3-D-CT angiography.

PURPOSE: We compared three-dimensional image (3-D-CT) angiography with conventional angiography to determine the clinical usefulness of this technique. MATERIALS AND METHODS: We studied 15 patients with cerebral aneurysms using dynamic CT with intravenous injection of contrast material and reconstructed 3-D-CT angiography. RESULTS: 3-D-CT angiography could be performed in conjunction with standard axial high-resolution CT without any additional scanning time and within 10-30 minutes for the overall study. All aneurysms were clearly visualized by 3-D-CT angiography. 3-D-reconstruction was very helpful in demonstrating the neck, shape, and direction of aneurysms, and adjacent vascular and bony structures. One small aneurysm that was difficult to detect on axial images was clearly visualized on 3-D-reconstruction. CONCLUSION: 3-D-CT angiography of cerebral aneurysms could be performed routinely and was helpful in demonstrating the complex anatomy of cerebral aneurysms and surrounding structures. This technique will be of value in surgical planning.

Adult↗

PubMedDate not supplied

Embolization of extensive facial arteriovenous malformation via the orbital branches of the ophthalmic artery.

Facial arteriovenous malformation (AVM) occasionally involves the orbit, and surgery for the orbital portion is complicated by its hypervascularity. We successfully embolized the orbital branches of the ophthalmic artery to decrease intraoperative bleeding of a facial AVM, sparing the ocular branches. There has been only one report dealing with embolization of the orbital branches of the ophthalmic artery.

Adult↗

PubMedDate not supplied

Contrast-enhanced MR images in patients with meningioma: importance of enhancement of the dura adjacent to the tumor.

Linear enhancement (flare sign) along the dura mater that was continuous with or emanated from the dural margin of meningiomas was frequently observed on contrast-enhanced MR images obtained in 18 patients with intracranial meningiomas (surgically proved). Preoperative MR studies obtained at 1.5 T after administration of gadopentetate dimeglumine were reviewed retrospectively to determine the clinical significance of this sign. Thirteen (72%) of the 18 meningiomas exhibited the finding adjacent to the dural attachments. Four meningiomas of the cerebellopontine angle showed enhancement along the internal auditory canals. Three specimens of the dura adjacent to the tumor in different patients with this finding revealed proliferation of connective tissues abounding with vessels along the dura without definite tumor invasion. The flare sign is thought to be a common finding of meningiomas on contrast-enhanced MR images obtained with high-resolution sequences, and it is observable without tumor invasion. This sign in the cerebellopontine angle should not be misinterpreted as enhancement of acoustic schwannomas.

Adult↗

PubMedDate not supplied

Brain tumors with ipsilateral cerebral hemiatrophy.

Brain tumors with secondary ipsilateral cerebral hemiatrophy are so rare that only seven cases have been reported in the literature. Three new cases are presented and the clinical findings in all 10 cases are reviewed. The diagnostic value of computed tomography (CT) is emphasized. The authors conclude that nodular high-density lesions located deep in the cerebrum and showing slight contrast enhancement on CT may be associated with ipsilateral cerebral hemiatrophy in young male patients with slowly progressive hemiparesis, dementia, and personality change. In such cases, early diagnosis of germinoma and subsequent radiotherapy may prevent unnecessary surgery.

Adolescent↗

PubMedDate not supplied

Direct cavernous sinus sampling.

To evaluate the potential of superselective cavernous sinus (CS) sampling in patients with functioning pituitary adenomas, we performed direct CS sampling in 18 patients with Cushing syndrome and other functioning adenomas using a mini-catheter. Samples from the inferior petrosal sinuses (IPS) were also obtained. All of the samples from 20 CS of 10 patients with Cushing syndrome and 13 of 16 samples from CS of eight patients with other adenomas were successfully obtained. No complication occurred. In three patients, the mini-catheter was introduced to the contralateral CS through intercavernous communication, and bilateral sampling could be performed via the unilateral jugular vein. The CS/peripheral (CS/P) ratio of ACTH (mean = 66.1) was significantly greater than the IPS/peripheral (IPS/P) ratio (mean = 14.9) in Cushing disease. In other functioning adenomas, the CS/P ratio (15.8) was not significantly higher than the IPS/P ratio (4.8). Direct CS sampling offers a much higher CS/P ratio than IPS/P ratio in Cushing disease, and may provide sufficient diagnostic accuracy without CRH stimulation or bilateral simultaneous sampling.

Adult↗

PubMedDate not supplied

Radiotherapy under informed consent report of a long-term survivor of advanced esophageal cancer.

This paper reports a patient with advanced esophageal cancer who has survived asymptomatically for five years after radiotherapy given under informed consent. Previously, we had not practiced radiotherapy under informed consent for patients with esophageal cancers. His excellent clinical course encouraged us to promote this form of treatment. This report presents his excellent clinical course in detail and discusses the significance of informed consent in radiotherapy for malignancies.

Aged↗

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↗