Repair of UV-induced thymine dimers is compromised in cells expressing the E6 protein from human papillomaviruses types 5 and 18

Ultraviolet (UV) irradiation is a major mutagenic environmental agent, causing the appearance of DNA adducts that, if unrepaired, may give rise to mutations. Ultraviolet radiation has been indicated as a major risk factor in the development of nonmelanoma skin cancers; however, recent reports have suggested that infections with human papillomaviruses, a widespread family of epitheliotropic DNA viruses, may also contribute to the tumorigeneic process. Here, we investigated whether expression of the E6 protein from different HPV types interfere with the repair of thymine dimers caused by UV-B radiation. Results show that unrepaired DNA damage can be observed in UV-B-irradiated cells expressing the E6 protein of HPV types found in cervical and epithelial cancers. Moreover, such cells have the ability to overcome the G(1) cell cycle checkpoint induced as a result of unrepaired DNA. (C) 2004 Cancer Research UK

Optimization of coronary optical coherence tomography imaging using the attenuation-compensated technique: a validation study.

PURPOSE To optimize conventional coronary optical coherence tomography (OCT) images using the attenuation-compensated technique to improve identification of plaques and the external elastic lamina (EEL) contour. METHOD The attenuation-compensated technique was optimized via manipulating contrast exponent C, and compression exponent N, to achieve an optimal contrast and signal-to-noise ratio (SNR). This was applied to 60 human coronary lesions (38 native and 22 stented) ex vivo conventional coronary OCT images acquired from heart autopsies of 10 patients and matching histology was available as reference. Three independent reviewers assessed the conventional and attenuation-compensated OCT images blindly for plaque characteristics and EEL detection. Conventional OCT and compensated OCT assessment were compared against histology. RESULTS Using an optimized algorithm, the attenuation-compensated OCT images had a 2-fold improvement in contrast between different tissues in both stented and non-stented epicardial coronaries (P <0.05). Overall sensitivity and specificity for plaque classification increased from 84 to 89% and from 92 to 94%, respectively, with substantial agreement among the three reviewers (Fleiss' Kappa k, 0.72 and 0.71, respectively). Furthermore, operators were 2.5 times more likely to identify the EEL contour in the attenuation-compensated OCT images (k = 0.72) than in the conventional OCT images (k = 0.36). CONCLUSION The attenuation-compensated technique can be retrospectively applied to conventional OCT images and improves the detection of plaque characteristics and the EEL contour. This approach could complement conventional OCT imaging in the evaluation of plaque characteristics and quantify plaque burden in the clinical setting

How clinically effective is intravascular ultrasound in interventional cardiology? Present and future perspectives

Intravascular ultrasound (IVUS) has been clinically available for almost 25 years now and showed us valuable information regarding the coronary vessel lumen, its dimensions, the plaque burden and plaque characteristics that we were not able to assess by angiography alone. Using these abilities, IVUS has helped us to start, understand the atherosclerotic process in the coronary vessels. Further technical innovations partially overcame the somewhat limited image resolution of IVUS allowing more in-depth characterization and quantification of coronary plaque components. In addition, IVUS has been shown to be helpful to guide interventional procedures including optimal stent deployment in many clinical situations. In this review, we focus on the potential role of IVUS technology in interventional cardiology and on the valuable role of IVUS usage in percutaneous coronary interventions