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Biomedical subjects

R Ito

Publications and source records attributed to R Ito.

205 records · Page 12Linked to original sources
PubMedDate not supplied

Metastatic adenocarcinoma presenting as a homogeneously high density mass on CT.

We report a case of metastatic adenocarcinoma to the brain that appeared as a homogeneously hyperdense mass on CT. The lesion was initially diagnosed as an intracerebral hematoma. On serial CT scans, the high density lesion progressively enlarged. Pathology showed coagulation necrosis without hemorrhage or calcification. Analysis of the tumor revealed elevation of the protein content relative to the normal brain. We conclude that the high CT attenuation was due to the elevated protein content.

Adenocarcinoma↗
PubMedDate not supplied

Simple calculation of the electron-backscatter factor.

The authors have studied the dependence of the electron-backscatter factor (EBF) on mean electron energy and on backscatterer atomic number by using the semiempirical depth-dose code EDMULT. A plane-parallel electron beam is assumed to be normally incident on a polystyrene slab, which is backed with a layer (backscatterer) of different materials of effectively semi-infinite thickness. A small air cavity to measure ionization is embedded in the polystyrene slab at the boundary facing the backscatterer. The EBF is defined as the ratio of the ionization with the backscatterer to the ionization with a full polystyrene medium, and is approximated by the ratio of the doses computed at the depth of the cavity. Values of EBF obtained show trends similar to the experimental data of Klevenhagen et al. [Phys. Med. Biol. 27, 263-373 (1982)], although the former are generally lower than the latter. When the typical energy spread of clinical electron beams is taken into account, the difference between the experimental and the calculated values is reduced. The present results also show the same trend of increase of the backscatter factor with increasing energy as observed by Klevenhagen et al. in some series of measurements for the lead backscatterer at the lowest energies. This is explained by the rapid buildup of the dose with depth for electrons of low initial energies incident on the full polystyrene medium.

Electrons↗
PubMedDate not supplied

Reduced expression of cyclin-dependent kinase inhibitor p27(Kip1) in oral malignant tumors.

p27(Kip1), a cyclin-dependent kinase (CDK) inhibitor, blocks progression from the G(1) to S phase by binding cyclin E-CDK2 and inhibiting their activities. We studied the expression of p27 in oral tumors by immunohistochemistry to determine whether lack of p27 plays a role in the development and progression of oral cancer. Reduced expression of p27 was detected in 86% of the squamous cell carcinomas and 95% of the mucoepidermoid carcinomas, respectively, while p27 expression was well preserved in the pleomorphic adenomas. The expression of p27 showed an inverse correlation with the expression of cyclin E in the squamous cell carcinomas and mucoepidermoid carcinomas. However, there was no relationship between clinicopathological parameters and p27 expression. These results suggest that the reduction of p27 protein may confer the development of oral squamous cell carcinoma and mucoepidermoid carcinoma partly through the increased expression of cyclin E.

Adenoma, Pleomorphic↗
PubMedDate not supplied

Endoscopic pericardial fenestration for a patient with sustained lupus pericarditis.

A 57-year-old woman was diagnosed in January 1982 with SLE based on ANA 1:640, positive LE cell preparation, proteinuria (3+), and pericarditis. In 1984, 1994, and 1997, the pericardial effusion was noted to have increased without signs of disease exacerbation or cardiac tamponade, and pericardial drainage was repeated to control the effusion. A massive pericardial effusion developed in August 1997. After tuberculosis, hypothyroidism, neoplasm, and progression of SLE were ruled out, we decided to perform pericardial fenestration. A safe and minimally invasive pericardial fenestration was successfully completed endoscopically. Pathologic study of the specimen revealed chronic pericarditis. We consider endoscopic pericardial fenestration to be useful for at risk patients with pericarditis to control the effusion and establish a differential diagnosis.

Endoscopy↗