No abstract

The macroscopic and microscopic redox potentials of the four hemes of the small tetraheme cytochrome c from Shewanella oneidensis were determined. The microscopic redox potentials show that the order of reduction is from hemes in the C-terminal domain (hemes 3 and 4) to the N-terminal domain (heme 1), demonstrating the polarization of the tetraheme chain during reduction. This makes heme 4 the most e⁄cient electron delivery site. Furthermore, multi-step reduction of other redox centers through either heme 4 or heme 3 is shown to be possible. This has provided new insights into the two-electron reduction of the £avin in the homologous £avocytochrome c^fumarate reductase.

Endoscopic resection is curative for superficial esophageal squamous cell carcinoma (ESCC) limited to the lamina propria. Endoscopic resection is not recommended for superficial ESCC invading muscularis mucosa or submucosa, however, because of the high frequency of lymph node metastasis (LNM) in such patients. Methods to more accurately predict LNM by analysis of endoscopically resected specimens are needed. Patients with superficial ESCC who underwent surgery without prior chemoradiotherapy (n= 110) were retrospectively examined to determine whether LNM correlated with immunohistochemical parameters and conventional histological parameters, including depth of invasion and vascular permeation. Cancer cell expression of claudins-1, 5, and 7, E-cadherin, beta-catenin, and matrix metalloproteinase 7 was evaluated. Univariate analysis revealed that LNM correlated with claudin-5 expression, but not any other immunohistochemical parameter examined. Multivariate analysis revealed three independent risk factors for LNM: aberrant claudin-5 expression in cancer cells (odds ratio; OR [95% confidence interval]= 4.61[1.44-14.77]), depth of submucosal invasion greater than 200 microm (3.55 [1.02-13.17]), and positive lymphatic permeation (3.34 [1.22-9.15]). LNM was found in one of 29 (3.4%) patients with none of these three risk factors, and in 32 of 81 (39.5%) patients with one or more of these risk factors. In superficial ESCC, routine analysis of claudin-5 expression in cancer cells together with depth of invasion and lymphatic permeation may be useful for predicting LNM and thereby reducing the number of patients undergoing additional surgery after successful endoscopic resection.

Objectives: The aim of this study was to determine the prevalence and to analyze the characteristics of p53 point mutation in esophageal intraepithelial lesions. Methods: p53 immunohistochemical and genetic analyses were performed on histopathologically and morphometrically diagnosed lesions. Laser capture microdissection samples were used for increased accuracy. Results: Of the 70 lesions studied, 21 were high-grade dysplasia/carcinoma in situ (HGD/CIS), 21 low-grade dysplasia (LGD), 16 reactive atypical epithelia (RAE) and 12 normal epithelia (NE).Immunohistochemical staining showed p53 protein accumulation in 86% (18/21) of HGD/CIS, 81% (17/21) of LGD, and in none of RAE and NE. p53 point mutation was detected in 71% (15/21) of HGD/CIS, 67% (14/21) of LGD, but in none of RAE and NE. Of HGD/CIS and LGD with p53 protein accumulation, similar percentages had mutations: 83% (15/18) and 82% (14/17), respectively. Of lesions with mutations, 72% (21/29) had mutations at hot spots such as codons 238, 248, 273 and 282. Conclusions: p53 point mutation prevalent in HGD/CIS was also present in a large number of LGD. This is strong evidence that LGD is a neoplastic lesion and that p53 point mutation is deeply involved in esophageal carcinogenesis.

The iPLA(2γ) enzyme is possibly involved in the pathogenesis of ALI following T/HS through the mesenteric lymph pathway.