44 research outputs found
Sunscreens - Which and what for?
No full textIt is well established that sun exposure is the main cause for the development of skin cancer. Chronic continuous UV radiation is believed to induce malignant melanoma, whereas intermittent high-dose UV exposure contributes to the occurrence of actinic keratosis as precursor lesions of squamous cell carcinoma as well as basal cell carcinoma. Not only photocarcinogenesis but also the mechanisms of photoaging have recently become apparent. In this respect the use of sunscreens seemed to prove to be more and more important and popular within the last decades. However, there is still inconsistency about the usefulness of sunscreens. Several studies show that inadequate use and incomplete UV spectrum efficacy may compromise protection more than previously expected. The sunscreen market is crowded by numerous products. Inorganic sunscreens such as zinc oxide and titanium oxide have a wide spectral range of activity compared to most of the organic sunscreen products. It is not uncommon for organic sunscreens to cause photocontact allergy, but their cosmetic acceptability is still superior to the one given by inorganic sunscreens. Recently, modern galenic approaches such as micronization and encapsulation allow the development of high-quality inorganic sunscreens. The potential systemic toxicity of organic sunscreens has lately primarily been discussed controversially in public, and several studies show contradictory results. Although a matter of debate, at present the sun protection factor (SPF) is the most reliable information for the consumer as a measure of sunscreen filter efficacy. In this context additional tests have been introduced for the evaluation of not only the protective effect against erythema but also protection against UV-induced immunological and mutational effects. Recently, combinations of UV filters with agents active in DNA repair have been introduced in order to improve photoprotection. This article reviews the efficacy of sunscreens in the prevention of epithelial and nonepithelial skin cancer, the effect on immunosuppression and the value of the SPF as well as new developments on the sunscreen market. Copyright (C) 2005 S. Karger AG, Basel
Using the Cancer Risk Management Model to evaluate colorectal cancer screening options for Canada
No full text
Patterns of mortality after prolonged follow-up of a randomised controlled trial using granulocyte colony-stimulating factor to maintain chemotherapy dose intensity in non-Hodgkin's lymphoma
No full textThe effect of utilising granulocyte colony-stimulating factor (G-CSF) to maintain chemotherapy dose intensity in non-Hodgkin's lymphoma (NHL) on long-term mortality patterns has not been formally evaluated. We analysed prolonged follow-up data from the first randomised controlled trial investigating this approach. Data on 10-year overall survival (OS), progression-free survival (PFS), freedom from progression (FFP) and incidence of second malignancies were collected for 80 patients with aggressive subtypes of NHL, who had been randomised to receive either VAPEC-B chemotherapy or VAPEC-B+G-CSF. Median follow-up was 15.7 years for surviving patients. No significant differences were found in PFS or OS. However, 10-year FFP was better in the G-CSF arm (68 vs 47%, P=0.037). Eleven deaths from causes unrelated to NHL or its treatment occurred in the G-CSF arm compared to five in controls. More deaths occurred from second malignancies (4 vs 2) and cardiovascular causes (5 vs 0) in the G-CSF arm. Although this pharmacovigilance study has insufficient statistical power to draw conclusions and is limited by the lack of data on smoking history and other cardiovascular risk factors, these unique long-term outcome data generate hypotheses that warrant further investigation
Using the Cancer Risk Management Model to evaluate the health and economic impacts of cytology compared with human papillomavirus DNA testing for primary cervical cancer screening in Canada
No full textThe OncoSim model: development and use for better decision-making in Canadian cancer control
No full textEstudo descritivo dos pacientes portadores de carcinoma basocelular operados no Hospital Universitário Prof. Plydoro Ernani de São Thiago
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Dapartamento de Clínica Cirúrgica
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Tumour chemo sensitivity assays: an investigation into the susceptibility of cells to chemotherapeutics
No full textTo evaluate and identify new candidate cancer drug targets, there is an ongoing need for a reliable, sensitive and quantitative assay that enables the analysis of larger numbers of compounds in preclinical research. This thesis has developed, and optimized a sensitive enzyme-release assay for monitoring natural cytotoxicity. It measures the release of the intracellular enzyme adenylate kinase into the culture supernatant after membrane rupture and is evaluated as an indicator of cell death. This assay was proven to correlate and compete with currently used methodologies for the assessment of cytotoxicity and with its superior sensitivity; convenience and in expense, it should be applicable to the study of other cytotoxicity reactions. The resulting ToxiLight® kit is now being sold world-wide and rapidly became the top selling product for Lonza Bio Science with many references to its use in publications.
It was proven from this investigation that to truly comprehend the effect a cytotoxic drug has on cells, two assays are required in combination; one to measure cytotoxicity and a second to measure viability. The two most sensitive kits tested in this study, the ViaLight® Plus assay and the newly designed ToxiLight® assay were used in combination to monitor the effect of commonly used cytotoxicity drugs on melanoma cells. It was hoped to find both a sensitive and resistant cell line for further analysis by MALDI-MS. The study revealed how cells of the same histological and tissue type can respond differently to the same anticancer drug with one cell line revealing cell death after treatment and another remaining unaffected. This is representative of how individual patients may respond differently to the treatments given in vitro and explains the vast biochemical heterogeneity of tumour cells and the complexity involved in developing anticancer drugs that will specifically kill tumours arising from a given cell. The primary melanoma cells used for the research were representative of the clinical situation and were a kind gift from the OYSTER (Outcome and Impact of Specific Treatment in European Research in melanoma) tissue bank; with the established cell lines obtained from ESTDAB. A selection of three of these cell lines (Ma Mel 28, Ma Mel 26a and MEWO) were chosen after investigating their sensitive/resistant nature to certain chemotherapeutic drugs and were further investigated with a novel agent currently in its early stages of drug trials, the histone deacetylase inhibitor, trichostatin A.
To investigate this resistance further, MALDI-MS was performed on the chosen melanoma cell lysates. The results demonstrated that good quality proteomic data could be achieved from cell lines and that it is possible to generate discriminatory protein profiles that correlate with the cytotoxicity assays when analysed using artificial neural networks (ANNs). Through the analysis of the proteome the ANNs was able to train itself using the raw dataset from the MALDI-MS analysis and distinguish differences between those samples that were drug-treated and those that were left untreated. The differences between the two classes of treated and untreated cells revealed biomarkers that may correlate to cell death and thus the effect of the drug trichostatin A.
These findings could lead to the discovery of proteins that are up regulated when a patient is responding to therapy. This could be of prognostic and therapeutic benefit to patients enabling them to find out in the early stages of treatment if they are responding to a given treatment; the long term outcome leading to personalised treatments for individuals in which a decision can be made on the best suited treatment
An ontology of ethnicity based upon personal names: with implications for neighbourhood profiling
No full textUnderstanding of the nature and detailed composition of ethnic groups remains key to a vast swathe of social science and human natural science. Yet ethnic origin is not easy to define, much less measure, and ascribing ethnic origins is one of the most contested and unstable research concepts of the last decade - not only in the social sciences, but also in human biology and medicine. As a result, much research remains hamstrung by the quality and availability of ethnicity classifications, constraining the meaningful subdivision of populations.
This PhD thesis develops an alternative ontology of ethnicity, using personal names to ascribe population ethnicity, at very fine geographical levels, and using a very detailed typology of ethnic groups optimised for the UK population. The outcome is an improved methodology for classifying population registers, as well as small areas, into cultural, ethnic and linguistic groups (CEL). This in turn makes possible the creation of much more detailed, frequently updatable representations of the ethnic kaleidoscope of UK cities, and can be further applied to other countries.
The thesis includes a review of the literature on ethnicity measurement and name analysis, and their applications in ethnic inequalities and geographical research. It presents the development of the new name to ethnicity classification methodology using both a heuristic and an automated and integrated approach. It is based on the UK Electoral Register as well as several health registers in London. Furthermore, a validation of the proposed name-based classification using different datasets is offered, as well as examples of applications in profiling neighbourhoods by ethnicity, in particular the measurement of residential segregation in London. The main study area is London, UK
