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Biomedical subjects

M Hashimoto

Publications and source records attributed to M Hashimoto.

1,399 records · Page 78Linked to original sources
PubMedDate not supplied

Oropharyngeal cancer: clinical efficacy of ultrasound.

Nine patients with carcinoma of the oropharynx were evaluated for classification of the primary tumor by ultrasonography (US). US accurately defined tumor size. In cancers of the tonsils, spread toward the tongue was correctly assessed by US. Tumor classification of T1 to T4 was possible in all patients. Small oropharyngeal cancers showed a homogeneous hypoechoic pattern. As the tumor enlarged, internal echoes became heterogeneous. US was also useful in evaluating the response to radiation by monitoring the tumor size. Our results showed that US was a valuable adjunct to current techniques for imaging oropharyngeal tumor.

Adult↗
PubMedDate not supplied

Preliminary study of uneven fractionation radiotherapy combined with chemotherapy for esophageal cancer.

Between March 1992 and September 1993, nine patients were treated with combined-modality therapy of uneven fractionation radiotherapy and chemotherapy (CDDP+ 5-FU) before esophagectomy. All patients had a T4 tumor that was evident on the chest CT scan, MRI, or bronchofiberscopy. In the uneven fractionation radiotherapy, patients received 5 Gy on Fridays and daily doses of 1.2 Gy the following Monday through Thursday for 22 days, to yield a total dose of 34.4 Gy. CDDP (40 mg/body) was administered intravenously as a slow infusion just before each 5 Gy treatment for a total of five doses. 5-FU (300 mg/m2/day) was also administered intravenously as a slow infusion for each of the 22 treatment days. As restaging failed to document a significant response (improvement to T3 or better), a further dose of irradiation was given in two patients (22%). Five patients (56%) had a partial response. The tumors in eight patients (89%) could be resected after this combined modality treatment. Histological assessment of the resected specimens indicated grade 3 in two patients and grade 2 in six patients. At a median follow-up of 14 months, seven patients are alive and four patients are clinically disease free. Uneven fractionation radiotherapy combined with chemotherapy improved local control and the resectable rate in these patients.

Adult↗
PubMedDate not supplied

Retrobulbar orbital metastasis mimicking meningioma.

A 45-year-old woman was found to have an intraorbital mass on CT. CT images showed a markedly enhanced retrobulbar mass with optic nerve lucency, producing a characteristic "tram-track" sign. Signal intensity patterns on spin-echo MRI seemed to indicate meningioma. The pathological diagnosis was scirrhous carcinoma of the breast. This case was not distinguishable from meningioma on CT or MRI.

Adenocarcinoma, Scirrhous↗
PubMedDate not supplied

Unusual widening of Virchow-Robin spaces: MR appearance.

MR in two patients with unusual widening of the Virchow-Robin spaces showed multiple cystic foci up to 2 cm in diameter along the perforating medullary arteries in the cerebral white matter, mainly in one cerebral hemisphere. These areas were of the same signal intensity as cerebrospinal fluid on all pulse sequences. In one patient, the cystic foci in the white matter were biopsied and histologically confirmed to be large Virchow-Robin spaces.

Aged↗
PubMedDate not supplied

The effects of a stress-absorbing system involved in the superstructure supported by hydroxyapatite-coated implants in monkeys.

To evaluate the effects of a stress-absorbing superstructure on the interface of an integrated implant, the bone/hydroxyapatite-coated (HA-coated) implant interface was histologically and histomorphometrically analyzed using monkeys. A total of 12 HA-coated implants were placed in the edentulous mandible of three monkeys. Polyurethane elastomer was selected as the stress-absorbing material. A superstructure incorporating a stress-absorbing system was placed on six implants (stress-absorbed group) and a superstructure without such a system was set on the other six implants (non-stress-absorbed group). After 12 months, undecalcified ground sections were prepared and the bone/implant interface was analyzed. Clinically, all implants in both groups were immobile and mild inflammation around the peri-implant gingiva was seen. Histologically, direct bone contact was observed around all of the implants in both groups. However, histomorphometrically, the amount of bone around implants was greater in the stress-absorbed group. Bone was more highly apposed to the implant at the apical portion than at the axial portion. These different findings could be the result of stress-breaking against functional loading to the bony interface of these HA-coated implants.

Alloys↗
PubMedDate not supplied

Superselective angio-CT of brain tumors.

PURPOSE: To determine the efficacy of superselective angio-CT in the diagnosis of astrocytoma. METHODS: Nineteen patients with astrocytoma had superselective angio-CT before chemotherapeutic agents were administered via superselective intraarterial infusion. CT was performed after contrast material was delivered through a microcatheter, which had been advanced into the feeding arteries of the tumor. Superselective angio-CT scans were compared with digital subtraction angiograms, conventional contrast-enhanced CT scans, and contrast-enhanced T1-weighted MR images. RESULTS: Superselective angio-CT scans depicted contrast enhancement of the tumor in all of the patients and the medullary veins of the tumors in 32% of the patients. Digital subtraction angiograms showed tumor stains in 68% of the patients and the medullary veins in only 5%. Conventional CT scans and MR images showed contrast enhancement of the tumor in 89% of the patients. Superselective angio-CT scans confirmed the proper position of the catheter tip for the infusion of a chemotherapeutic agent. CONCLUSIONS: Superselective angio-CT can be used to depict contrast enhancement of tumors and the vascular structures that are characteristic of astrocytomas.

Adult↗
PubMedDate not supplied

Angiographic anatomy of the first and second segments of the maxillary artery.

The increasing use of interventional angiography makes it important to know the anatomy of the maxillary artery. The course and ramification pattern of the first and second segments of this artery were studied angiographically in 100 cases. The branches of the maxillary artery were identified on lateral stereoscopic images. The maxillary artery has three segments divided by the external pterygoid muscle, and the second of these segments divides into superficial and deep types. Of the 100 Japanese angiograms, 93% were of the superficial type and 7% of the deep type. The 93% was a much higher incidence than in Western populations. In the superficial types, the middle deep temporal artery and inferior alveolar artery arose separately from the maxillary artery, while in the deep types, they had a common trunk. This made it easy to differentiate the two types. The maxillary artery was classified into four subgroups (Ia, Ib, IIa and IIb) by the ramification patterns of the middle meningeal and accessory meningeal arteries from the first segment.

Angiography, Digital Subtraction↗
PubMedDate not supplied

Computed tomographic appearance of closed-loop obstruction.

The obstruction of a bowel segment at two points results in closed-loop obstruction, and is apt to cause strangulation. Thus, the early recognition of closed-loop small bowel obstruction might reduce the mortality rate. However, plain films are limited in their ability to diagnose it. Using previously described criteria, we retrospectively reviewed the CT images of six surgically confirmed cases of closed loop obstruction. In all patients, CT showed the characteristic configuration of closed loops, specific findings detected at the site of obstruction, or both. On the basis of our experience, CT is a useful, non invasive method for the investigation of patients with suspected closed-loop obstruction.

Adult↗
PubMedDate not supplied

Growth patterns of benign and malignant thyroid tumors estimated by CT.

Thyroid tumors affect adjacent structures and reveal their nature as they grow. Differences in benign and malignant tumor growth patterns were studied by CT. Twenty-nine benign (follicular adenoma) and 29 malignant (papillary carcinoma) tumors with their findings were arranged according to size to speculate on how they grew. Benign tumors grew expansively and made a beak-like appearance in the marginal thyroid tissue (beak sign). They displaced vessels but kept a fat plane or deep sulcus between them (sulcus sign). Malignant tumors, on the other hand, grew invasively and reached the trachea rapidly without the beak sign. They destroyed the fat plane and contacted the vessels without the sulcus sign. Expansive and invasive growth forms of benign and malignant thyroid tumors could be represented schematically.

Adenoma↗
PubMedDate not supplied

Comparison of fast spin-echo and conventional spin-echo sequences in the MR diagnosis of rotator cuff tears.

The fast spin-echo (FSE) technique has been a successful alternative to conventional spin-echo (CSE) imaging in the brain, spine, and pelvis, but not in the knee. This study evaluated the performance of the FSE technique in comparison with the established CSE technique as a reference standard. Oblique coronal images of 30 shoulders were obtained by both FSE and CSE techniques. The FSE images were compared with CSE images in terms of blurring and motion artifact, fat signal intensity, structural conspicuity, and visualization of joint effusion and rotator cuff tears. We imaged 30 consecutive patients with suspected rotator cuff tears who were referred for MR examination. FSE images often were worse in blurring and motion artifact than CSE images. FSE images showed higher fat signal intensity, but visualized structural conspicuity, joint effusion, and rotator cuff tear as well as CSE images. Our results suggest that the FSE technique is not equal to the CSE technique but can be used for the diagnosis of rotator cuff tears.

Adolescent↗
PubMedDate not supplied

Stimulation of human tumor xenograft growth by local estrogen biosynthesis in stromal cells.

BACKGROUND: Both biochemical and histochemical studies have demonstrated the expression of aromatase activity in stromal cells surrounding breast cancers, suggesting that local estrogen biosynthesis promotes the growth of these cancers. However, the role of local aromatase activity in stimulating hormone-dependent breast cancer is still controversial. MATERIALS AND METHODS: A hormone-dependent human breast carcinoma xenograft, Br-10 and human fibroblast cells obtained from a patient with benign breast disease were used in the experiments. When subcutaneously inoculated Br-10 started exponential growth in female nude mice, 10(6) fibroblast cells were injected around the tumor with or without intramuscular administration of 50 mg/kg testosterone. RESULTS: The growth of Br-10 treated with fibroblasts and testosterone was significantly enhanced in comparison with the control (p < 0.05). This stimulation by fibroblasts and testosterone was also observed in ovariectomized nude mice. Immunohistochemical staining for aromatase was observed in tumor sections containing Br-10 from mice treated with fibroblasts and testosterone, particularly around the carcinomatous glands. CONCLUSION: We conclude that estrogen produced locally by aromatase in fibroblasts can regulate the growth of hormone-dependent breast carcinoma cells.

Animals↗
PubMedDate not supplied

Management of the pancreatic metastases from renal cell carcinoma: report of four resected cases.

The pancreas is an uncommon site for metastasis from renal cell carcinoma. In most cases, pancreatic metastases occur as part of widespread nodal and visceral involvement, and there is thus evidence of metastatic disease elsewhere in the body. We present 4 cases with resectable pancreatic metastases arising from renal cell tumors without involvement of the regional lymph nodes at the operation. Three cases out of 4 were asymptomatic and the pancreatic metastases were detected by routine follow-up examination of renal cell carcinoma. Aggressive surgical treatment for the solitary metastatic lesion is advocated. Spread of renal cell carcinoma to the pancreas is, however, via the hematogenous route, and even solitary pancreatic metastasis may be one of the manifestations of the systemic metastasis of renal cell carcinoma. No pancreatic regional lymph nodes metastases were noted. Pancreatectomy should be undertaken to remove the tumor with adequate resection margins while preserving as much of the gland as possible. The prognosis of pancreatic metastases arising from a renal cell carcinoma is discussed with a review of the literature. Adjuvant chemo- and endocrine therapy should also be considered in these cases.

Aged↗