Developmental, morphological and physiological effects of chronic low doses of ionising radiation on plants on earth and in space

Conclusions in the current literature are essentially unanimous regarding what is known about the effects of ionising radiation on plants. It is agreed that acute high-dose effects (primarily from laboratory tests) are well-documented and understood but that the same cannot be said for lower doses. ‘Low-dose’ research is itself contentious until there is sufficient understanding to define what constitutes a ‘low’ dose. Studies using lower doses typically (but with some notable exceptions) feature dose-effect relationships at doses to plants orders of magnitude lower than high-dose studies (i.e. they examine doses measured in μGy-mGy as opposed to kGy-Gy). A compilation of data reported here emphasises not only the lack of studies that utilise low and environmentally-realistic doses of ionising radiation (μGy-mGy) but also the particular lack of such experiments that used a controlled environment. Additionally, the compilation revealed a lack of transgenerational studies. In research reported here five generations of Arabidopsis thaliana were grown in soil contaminated with Cs-137 at low field-relevant dose rates (35 μGy/h). The developmental stages defined by a long-established phenotypic model (Boyes et al., 2001) were charted over entire life cycles. A detailed analysis of leaf morphology in generations of radioactively-exposed plants was undertaken with semi-autonomous image analysis software (LAMINA- Leaf shApe deterMINAtion). The same leaves were analysed for antioxidant changes via an assay for glutathione. No transgenerational trends were identified in any of the endpoints examined. Significant changes were detected in development and morphology in some treatments in some generations and are in line with stochastic effects expected to occur over generations in the conditions. No significant differences were found in glutathione concentrations. No significant differences in root length were found between treatments or between generations. Lastly, seeds from two species of crop plants Eruca sativa and Solanum lycopersicum (rocket and tomato) that had flown aboard the International Space Station, and that had received a cosmic radiation dose in low-Earth orbit of similar magnitude to the Arabidopsis, were grown in Cs-137 contaminated soil. Previous exposure to cosmic radiation as seeds did not change uptake characteristics of either species or total growth or root length. In conclusion, while some effects have been observed, nothing was found to suggest that doses of ionising radiation at ‘low’ doses has a significant, negative impact on generations and populations of plants throughout these experiments. This contrasts with many reports from the field at similar dose rates and provides evidence that: a) current radioprotection limits are satisfactory at protecting plant populations, b) many effects on plants of low-dose radiation reported from the field are due to either past exposures to populations or other environmental factors and c) what constitutes a low dose of ionising radiation to plants could be redefined

Treatment challenges in and outside a specialist network setting: Pancreatic neuroendocrine tumours

Pancreatic Neuroendocrine Neoplasms comprise a group of rare tumours with special biology, an often indolent behaviour and particular diagnostic and therapeutic requirements. The specialized biochemical tests and radiological investigations, the complexity of surgical options and the variety of medical treatments that require individual tailoring, mandate a multidisciplinary approach that can be optimally achieved through an organized network. The present study describes currents concepts in the management of these tumours as well as an insight into the challenges of delivering the pathway in and outside a Network

Superconductivity in an Einstein Solid AxV2Al20 (A = Al and Ga)

A cage compound AxV2Al20 (Al10V), that was called an Einstein solid by Caplin and coworkers 40 years ago, is revisited to investigate the low-energy, local vibrations of the A atoms and their influence on the electronic and superconducting properties of the compound. Polycrystalline samples with A = Al, Ga, Y, and La are studied through resistivity and heat capacity measurements. Weak-coupling BCS superconductivity is observed below Tc = 1.49, 1.66, and 0.69 K for Ax = Al0.3, Ga0.2, and Y, respectively, but not above 0.4 K for Ax = La. Low-energy modes are detected only for A = Al and Ga, which are approximately described by the Einstein model with Einstein temperatures of 24 and 8 K, respectively. A weak but significant coupling between the low-energy modes, which are almost identical to those called rattling in recent study, and conduction electrons manifests itself as anomalous enhancement in resistivity at around low temperatures corresponding to the Einstein temperatures.Comment: 12 pages, 5 figures, to be published in J. Phys. Soc. Jp

Prostate cancer and the influence of dietary factors and supplements: a systematic review

Background Prostate cancer is the second most common cause of cancer worldwide after lung cancer. There is increasing evidence that diet and lifestyle plays a crucial role in prostate cancer biology and tumourigenesis. Prostate cancer itself represents a good model of cancer in which to look for chemopreventive agents due to the high disease prevalence, slowly progressive nature, and long latency period. Dietary agents have gained considerable attention, often receiving much publicity in the media. Aim To review the key evidence available for potential chemopreventive nutrients. Methods The methodology for this review involved a PubMed search from 1990 to 2013 using the key-words “diet and prostate cancer”, “nutrition and prostate cancer”, “dietary factors and prostate cancer”, “prostate cancer epidemiology”, “prostate cancer prevention”, “prostate cancer progression”. Results Red meat, dietary fat and milk intake should be minimised as they appear to increase the risk of prostate cancer. Fruit and vegetables and polyphenols may be preventive in prostate cancer, but further studies are needed to draw more solid conclusions and to clarify their role in patients with an established diagnosis of prostate cancer. Selenium and vitamin supplements cannot be advocated for the prevention of prostate cancer and indeed higher doses may be associated with a worse prognosis. There is no specific evidence regarding benefits of probiotics or prebiotics in prostate cancer. Conclusions From the wealth of evidence available, many recommendations can be made although more randomised control trials are required. These need to be carefully designed due to the many confounding factors and heterogeneity of the population