RESUMO
BACKGROUND: The large number of diagnostic procedures undertaken in emergency departments (ED) is vital to the early diagnosis and treatment of patients. The use of ionising radiation in diagnosis adds a lifetime attributable risk (LAR) of cancer depending on the region imaged, the frequency of imaging, and dose per exposure. AIMS: This pilot study aims to assess the degree of radiation awareness amongst ED doctors at major metropolitan and regional health services in Australia, in terms of the dose and risks associated with common imaging. Secondary aims were to provide a template to practically evaluate ED doctor radiation awareness, identify factors impacting upon radiation awareness (e.g., location, seniority of doctor), and to suggest practical means to improve radiation awareness. METHODS: Physicians in the EDs of two major health services (one regional and one metropolitan) in Australia were surveyed and asked to compare the radiation dose from each procedure to what the general population is exposed to naturally from background radiation. Additionally, the physicians were asked to estimate the LAR of cancer from each diagnostic procedure. These estimates were compared to literature-sourced values to assess the accuracy of physician responses. RESULTS: Results showed that there was significant variance with regard to knowledge of dose and risk, and that respondents tended to greatly overexaggerate the radiation levels and risk associated with diagnostic imaging. Despite failing to attribute correct values, in many cases, respondents ranked scans correctly. Responses comparing differences amongst the two health services and amongst different levels of medical hierarchy largely overlapped with no clear difference between these factors. CONCLUSION: Physicians reported low confidence in their knowledge of radiation awareness and indicated the need for additional education, which would assist them in communicating the risks to patients. Furthermore, such education would assist physicians in tailoring their diagnostic imaging requests so as to minimise radiation levels in patients.
RESUMO
Anti-proliferative and pro-apoptotic effects of Bay leaf (Laurus nobilis) in mammalian cancer and HT-29 adenocarcinoma cells have been previously attributed to effects of polyphenolic and essential oil chemical species. Recently, we demonstrated differentiated growth-regulating effects of high (HFBL) versus low molecular mass (LFBL) aqueous fractions of bay leaf and now confirm by comparative effects on gene expression, that HFBL and LFBL suppress HT-29 growth by distinct mechanisms. Induction of intra-cellular lesions including DNA strand breakage by extra-cellular HFBL, invoked the hypothesis that iron-mediated reactive oxygen species with capacity to penetrate cell membrane, were responsible for HFBL-mediated effects, supported by equivalent effects of HFBL in combination with γ radiation. Activities of HFBL and LFBL were interpreted to reflect differentiated responses to iron-mediated reactive oxygen species (ROS), occurring either outside or inside cells. In the presence of LFBL, apoptotic death was relatively delayed compared with HFBL. ROS production by LFBL mediated p53-dependent apoptosis and recovery was suppressed by promoting G1/S phase arrest and failure of cellular tight junctions. In comparison, intra-cellular anti-oxidant protection exerted by LFBL was absent for extra-cellular HFBL (likely polysaccharide-rich), which potentiated more rapid apoptosis by producing DNA double strand breaks. Differentiated effects on expression of genes regulating ROS defense and chromatic condensation by LFBL versus HFBL, were observed. The results support ferrous iron in cell culture systems and potentially in vivo, can invoke different extra-cellular versus intra-cellular ROS-mediated chemistries, that may be regulated by exogenous, including dietary species.