Value of bronchoscopy after EUS in the preoperative assessment of patients with esophageal cancer at or above the carina

Introduction: Esophageal cancer is an aggressive disease with a strong tendency to infiltrate into surrounding structures. The aim of the present study is to determine the additional value of bronchoscopy for detecting invasion of the tracheobronchial tree after endoscopic ultrasonography (EUS) in the preoperative assessment of patients with esophageal cancer at or above the carina. Materials and Methods: Between January 1997 and December 2006, 104 patients were analyzed for histologically proven esophageal cancer at or above the carina. All patients underwent both EUS and bronchoscopy (with biopsy on indication) in the preoperative assessment of local resectability. Results and Discussion: After extensive diagnostic workup, 58 of 104 patients (56%) were eligible for potentially curative esophagectomy; nine of these 58 patients (9/58, 15%) appeared to be incurable peroperatively because of ingrowth in the tracheobronchial tree (five patients), ingrowth in other vital structures (two patients) or distant metastases (two patients). Of the 46 non-operable patients, local irresectability (T-stage 4) was identified in 26 patients (26/46, 57%) due to invasion of vital structures on EUS: invasion of the aorta in six patients, invasion of the lung in 11 patients; in 12 patients invasion of the tracheobronchial tree was described, which was confirmed by bronchoscopy in only five patients. No patients with T4 were identified by bronchoscopy alone. Conclusion: For patients with esophageal tumors at or above the carina, no additional value of bronchoscopy (with biopsy on indication) to exclude invasion of the tracheobronchial tree was seen after EUS in a specialized centre. Although based on relatively small numbers, we conclude that bronchoscopy is not indicated if no invasion of the airways is identified on EUS

Short RNA Guides Cleavage by Eukaryotic RNase III

In eukaryotes, short RNAs guide a variety of enzymatic activities that range from RNA editing to translation repression. It is hypothesized that pre-existing proteins evolved to bind and use guide RNA during evolution. However, the capacity of modern proteins to adopt new RNA guides has never been demonstrated. Here we show that Rnt1p, the yeast orthologue of the bacterial dsRNA-specific RNase III, can bind short RNA transcripts and use them as guides for sequence-specific cleavage. Target cleavage occurred at a constant distance from the Rnt1p binding site, leaving the guide RNA intact for subsequent cleavage. Our results indicate that RNase III may trigger sequence-specific RNA degradation independent of the RNAi machinery, and they open the road for a new generation of precise RNA silencing tools that do not trigger a dsRNA-mediated immune response

Lacrimal Hypofunction as a New Mechanism of Dry Eye in Visual Display Terminal Users

BACKGROUND: Dry eye has shown a marked increase due to visual display terminal (VDT) use. It remains unclear whether reduced blinking while focusing can have a direct deleterious impact on the lacrimal gland function. To address this issue that potentially affects the life quality, we conducted a large-scale epidemiological study of VDT users and an animal study. METHODOLOGY/PRINCIPAL FINDINGS: Cross sectional survey carried out in Japan. A total of 1025 office workers who use VDT were enrolled. The association between VDT work duration and changes in tear film status, precorneal tear stability, lipid layer status and tear secretion were analyzed. For the animal model study, the rat VDT user model, placing rats onto a balance swing in combination with exposure to an evaporative environment was used to analyze lacrimal gland function. There was no positive relationship between VDT working duration and change in tear film stability and lipid layer status. The odds ratio for decrease in Schirmer score, index of tear secretion, were significantly increased with VDT working year (P = 0.012) and time (P = 0.005). The rat VDT user model, showed chronic reduction of tear secretion and was accompanied by an impairment of the lacrimal gland function and morphology. This dysfunction was recovered when rats were moved to resting conditions without the swing. CONCLUSIONS/SIGNIFICANCE: These data suggest that lacrimal gland hypofunction is associated with VDT use and may be a critical mechanism for VDT-associated dry eye. We believe this to be the first mechanistic link to the pathogenesis of dry eye in office workers

A computational model of liver iron metabolism

Iron is essential for all known life due to its redox properties; however, these same properties can also lead to its toxicity in overload through the production of reactive oxygen species. Robust systemic and cellular control are required to maintain safe levels of iron, and the liver seems to be where this regulation is mainly located. Iron misregulation is implicated in many diseases, and as our understanding of iron metabolism improves, the list of iron-related disorders grows. Recent developments have resulted in greater knowledge of the fate of iron in the body and have led to a detailed map of its metabolism; however, a quantitative understanding at the systems level of how its components interact to produce tight regulation remains elusive. A mechanistic computational model of human liver iron metabolism, which includes the core regulatory components, is presented here. It was constructed based on known mechanisms of regulation and on their kinetic properties, obtained from several publications. The model was then quantitatively validated by comparing its results with previously published physiological data, and it is able to reproduce multiple experimental findings. A time course simulation following an oral dose of iron was compared to a clinical time course study and the simulation was found to recreate the dynamics and time scale of the systems response to iron challenge. A disease state simulation of haemochromatosis was created by altering a single reaction parameter that mimics a human haemochromatosis gene (HFE) mutation. The simulation provides a quantitative understanding of the liver iron overload that arises in this disease. This model supports and supplements understanding of the role of the liver as an iron sensor and provides a framework for further modelling, including simulations to identify valuable drug targets and design of experiments to improve further our knowledge of this system