Biomedical subjects

T Toyota

Publications and source records attributed to T Toyota.

419 records · Page 24Linked to original sources

PubMedDate not supplied

Serrated adenoma: a clinicopathological, DNA ploidy, and immunohistochemical study.

AIMS: Serrated adenoma (SA) is a relatively newly defined entity of colorectal neoplasm. In this study, we examined the cell proliferation, DNA ploidy, and clinicopathological features of SA in order to investigate its biological features. METHODS AND RESULTS: We reviewed 10,532 polypectomy specimens of the colorectum obtained from Japanese cases between 1974 and 1998 at Tohoku University Hospital. In total, 193 cases of SA were detected. We first examined clinical features of these cases by reviewing the charts, and then studied cell proliferation using immunohistochemistry of Ki-67 and topoisomeraseIIa, p53 immunoreactivity and DNA ploidy. Results were subsequently compared with those of tubular adenoma (TA) and hyperplastic polyp (HP). Mean size of SA (8.6 +/- 4.6 mm) was significantly larger than those of TA (7.3 +/- 4.6 mm) and HP (5.6 +/- 3.0 mm). More than 80% of SA were protuberant in macroscopic appearance. SA was located predominantly in the sigmoid colon and rectum. Incidences of concomitant carcinoma in HP, SA and TA were 0.4% (1 out of 263), 4.1% (8 out of 193) and 10.3% (809 out of 7838), respectively. Labeling indices for Ki-67 and topoisomeraseIIa in HP, SA and TA were as follows: Ki-67--24.2%, 30.8%, 39.5% and topoisomeraseIIa--15.3%, 16.1%, 23.9%, respectively. In SA, p53 immunoreactivity was detected in the intramucosal carcinoma co-existing with the serrated component. Two out of the ten SA cases examined demonstrated non-diploid patterns of DNA ploidy. CONCLUSION: SA is a distinct colorectal neoplastic lesion with the potential of malignant transformation similar to that of tubular adenoma.

Adenoma↗

PubMedDate not supplied

Clinical application of low calcium peritoneal dialysate.

Low calcium dialysate (LCa) with calcium levels of 2.3 mEq/L was prepared for peritoneal dialysis, and its equilibration was compared with those of conventional dialysates with calcium contents of 3.5 mEq/L and 4.0 mEq/L. The variation in dialysate to plasma concentration ratios of total calcium of conventional dialysates was positive; that of LCa was negative. Mass transfer of calcium per day was positive and normal for calciums of 4.0 mEq/L (31 +/- 51 mg/day) and 3.5 mEq/L (-37 +/- 40 mg/day), compared with a negative balance for LCa (-157 +/- 26 mg/day). The LCa was used in six patients over 6 months. The doses of calcium carbonate and vitamin D also were increased from 1.2 +/- 1.5 to 5.4 +/- 3.3 g/day (p less than 0.05) and from 0.17 +/- 0.2 to 0.38 +/- 0.47 micrograms/day, respectively. Aluminum gel was discontinued. Low calcium dialysate may become the standard dialysate for stable continuous ambulatory peritoneal dialysis patients.

Adult↗

PubMedDate not supplied

Analysis of p53 abnormalities in endoscopic gastric biopsies.

We performed immunohistochemical staining for p53 in 152 endoscopic gastric biopsy specimens, including 39 adenomas, 80 carcinomas, and 33 cases of regenerative atypia. Direct DNA sequencing of exons 5,7 and 8 of the p53 gene was performed on 8 specimens. Nuclear p53 immunoreactivity was observed in 36 of 80 carcinomas, 7 of 39 adenomas and none of the cases of regenerative atypia. Three of the adenomas demonstrated diffuse or focal p53 immunoreactivity. All three cases were associated with severe degrees of epithelial dysplasia, and two of them harbored carcinoma on subsequent polypectomy. Among 6 p53 positive carcinomas and adenomas sequenced, 3 showed DNA mutations, all G:C to A:T transitions. These results indicate that positive p53 immunoreactivity in intraepithelial atypical cells on gastric biopsies represents true dysplasia or carcinoma rather than regenerative atypia.

Adenocarcinoma↗

PubMedDate not supplied

Expression of CD44 in duct cell carcinomas and in intraductal neoplasms of the pancreas.

The expression of alternatively spliced CD44 isoforms, especially so-called variant exons v5 and v6, has been shown to correlate with the progression of a number of human cancers examined the expression of standard CD44 and CD44 variants with exons v5 and v6 in 28 cases of human pancreatic tumors (16 cases of invasive duct cell adenocarcinoma and 12 cases of intraductal neoplasms) by immunohistochemistry using exon specific monoclonal antibodies. The expression of standard CD44 was frequently observed in both invasive duct cell carcinomas and intraductal neoplasms. The expression of CD44 variants (v5 and v6) was also seen in almost all duct cell carcinomas. In contrast, intraductal neoplasms infrequently expressed CD44-v5 and -v6, particularly v6 exon. Expression of CD44-v5 and v6 was a common characteristic of invasive cancer, while it was not so prominent in intraductal neoplasm. These findings may be related to the invasiveness of duct cell carcinoma and/or the benign biological behavior of intraductal neoplasm of the pancreas.

Carcinoma, Ductal, Breast↗

PubMedDate not supplied

Immunohistochemistry of Caspase3/CPP32 in human stomach and its correlation with cell proliferation and apoptosis.

Caspase3/CPP32 is a member of the interleukin-1 beta-converting enzyme (ICE) or cell death effector (CED)-3 family, which is involved in the induction of apoptosis and has been considered to be correlated with apoptosis because of the most downstream enzyme in their apoptosis inducing pathway. We immunolocalized Caspase3/CPP32 in both normal and neoplastic human gastric mucosa. We then correlated the findings with cell proliferation studied by Ki67 immunostaining and apoptosis, which was tested for by DNA fragmentation in situ using TdT-mediated dUTP biotin nick end labeling (TUNEL) method in order to examine possible biological significance in cell turnover of normal and pathological human gastric tissues. Caspase3/CPP32 immunoreactivity was detected in both the cytoplasm and nuclei of glandular epithelial cells, predominantly in the Ki67 positive proliferative zone and TUNEL positive foveolar epithelium of normal non-neoplastic gastric mucosa (n = 10) and tumor cells of both adenoma (n = 17) and carcinoma (n = 33). We determined the labeling index (LI) of Ki67, Caspase3/CPP32 and TUNEL positive cells by evaluating the number of positive cells in the same areas of serial tissue sections using computer-assisted image analysis. Ki67 LI in adenocarcinoma (78.6 +/- 12.6%) was significantly [p < 0.0001] higher than that of adenoma (43.8 +/- 8.9%) and non-neoplastic gastric mucosa (24.2 +/- 9.0%). Caspase3/CPP32 LI in adenocarcinoma (17.1 +/- 10.3%) was significantly lower [p < 0.0001] than that of gastric adenoma (33.1 +/- 19.8%) and non-neoplastic gastric mucosa (42.4 +/- 15.8%). TUNEL LI in adenocarcinoma (1.9 +/- 2.1%) was significantly [p < 0.0001] lower than that of non-neoplastic gastric mucosa (6.0 +/- 3.5%), but not significantly different from that of adenoma (3.0 +/- 2.9%). These results indicate that gastric adenocarcinoma is associated with an inhibition of apoptosis and the augmentation of proliferative activity of tumor cells compared to non-neoplastic gastric mucosa. There was a tendency to a positive correlation between the Caspase3/CPP32 and TUNEL LI and an inverse correlation between the Caspase3/CPP32 and Ki67 LI, when evaluating all the specimens, although the correlation did not reach statistical significance. These results also suggest that Caspase3/CPP32 is involved in the development or regulation of apoptotic cell death in cell turnover of normal and neoplastic mucosa of the human stomach.

Adenocarcinoma↗