Current concepts of tumour metastasis

Background: Tumour metastasis remains the principal cause of treatment failure and poor prognosis in patients with cancer. Recent advances in our understanding of the biology of metastasis are providing novel potential targets for anti-cancer therapies. Aim: This paper reviews the current concepts in tumour metastasis. Methods: A review of Medline publications relating to the molecular biology and therapy of human tumour metastasis was conducted. Results and Discussion: Early metastasis models were based upon the premise of uninterrupted tumour growth, with the inevitable formation of distant metastases and eventual death of the patient. However, current research suggests that metastasis is an inefficient process governed by several rate-limiting steps, and that failure to negotiate these steps can lead to tumour dormancy. Successful metastatic tumour growth depends upon appropriate tumour-host microenvironment interactions and, ultimately, the development of vascularised metastases post-extravasation in the target organ. An understanding of the molecular mechanisms involved in this dynamic process will aid in the identification of therapeutic targets that may allow earlier diagnosis and more specific therapies for patients with metastasis.

Depth of cure and surface microhardness of composite resin cured with blue LED curing lights

Objectives. This study examined the depth of cure and surface microhardness of Filtek Z250 composite resin (3M-Espe) (shades B1, A3, and C4) when cured with three commercially available tight emitting diode (LED) curing lights [E-light (GC), Elipar Freelight (3M-ESPE), 475H (RF Lab Systems)], compared with a high intensity quartz tungsten halogen (HQTH) light (Kerr Demetron Optilux 501) and a conventional quartz tungsten halogen (QTH) lamp (Sirona S1 dental unit). Methods. The effects of light source and resin shade were evaluated as independent variables. Depth of cure after 40 s of exposure was determined using the ISO 4049:2000 method, and Vickers hardness determined at 1.0 mm intervals. Results. HQTH and QTH lamps gave the greatest depth of cure. The three LED lights showed similar performances across all parameters, and each unit exceeded the ISO standard for depth of cure except GC ELight for shade B1. In terms of shade, LED lights gave greater curing depths with A3 shade, while QTH and HQTH tights gave greater curing depths with C4 shade. Hardness at the resin surface was not significantly different between LED and conventional curing lights, however, below the surface, hardness reduced more rapidly for the LED lights, especially at depths beyond 3 mm. Significance. Since the performance of the three LED lights meets the ISO standard for depth of cure, these systems appear suitable for routine clinical application for resin curing. (C) 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Uncovering a hidden epidemic: A study of the current burden of heart failure in Australia

Background. Australia, like other countries, is experiencing an epidemic of heart failure (HF). However, given the lack of national and population-based datasets collating detailed cardiovascular-specific morbidity and mortality outcomes, quantifying the specific burden imposed by HF has been difficult. Methods. Australian Bureau of Statistics (ABS data) for the year 2000 were used in combination with contemporary, well-validated population-based epidemiologic data to estimate the number of individuals with symptomatic and asymptomatic HF related to both preserved (diastolic dysfunction) and impaired left ventricular systolic (dys)function (LVSD) and rates of HF-related hospitalisation. Results. In 2000, we estimate that around 325,000 Australians (58% male) had symptomatic HF associated with both LVSD and diastolic dysfunction and an additional 214,000 with asymptomatic LVSD. 140,000 (26%) live in rural and remote regions, distal to specialist health care services. There was an estimated 22,000 incidents of admissions for congestive heart failure and approximately 100,000 admissions associated with this syndrome overall. Conclusion. Australia is in the midst of a HF epidemic that continues to grow. Overall, it probably contributes to over 1.4 million days of hospitalization at a cost of more than $1 billion. A national response to further quantify and address this enormous health problem is required.