Peto's paradox: Nature has used multiple strategies to keep cancer at bay while evolving long lifespans and large body masses. A systematic review

Comparative oncology is an understudied field of science. We are far from understanding the key mechanisms behind Peto's paradox, i.e., understanding how long-lived and large animals are not subject to a higher cancer burden despite the longer exposure time to mutations and the larger number of cells exposed. In this work, we investigated the scientific evidence on such mechanisms through a systematic mini-review of the literature about the relation of longevity and/or large body mass with physiological, genetic, or environmental traits among mammalian species. More than forty thousand articles were retrieved from three repositories, and 383 of them were screened using an active-learning-based tool. Of those, 36 articles on longevity and 37 on body mass were selected for the review. Such articles were examined focusing on: number and type of species considered, statistical methods used, traits investigated, and observed relationship with longevity and/or body mass. Where applicable, the traits investigated were matched with one or more hallmarks of cancer. We obtained a list of potential candidate traits to explain Peto's paradox related to replicative immortality, cell senescence, genome instability and mutations, proliferative signaling, growth suppression evasion, and cell resistance to death. Our investigation suggests that different strategies have been followed to prevent cancer in large and long-lived species. The large number of papers retrieved emphasizes that more studies can be launched in the future, using more efficient analytical approaches to comprehensively evaluate the convergent biological mechanisms essential for acquiring longevity and large body mass without increasing cancer risk.

Review of petroleum toxicity and identifying common endpoints for future research on diluted bitumen toxicity in marine mammals

Large volumes of conventional crude oil continue to be shipped by sea from production to consumption areas across the globe. In addition, unconventional petroleum products also transverse pelagic habitats; for example, diluted bitumen from Canada's oilsands which is shipped along the Pacific coast to the United States and Asia. Therefore, there is a continuing need to assess the toxicological consequences of chronic and catastrophic petroleum spillage on marine wildlife. Peer-reviewed literature on the toxicity of unconventional petroleum such as diluted bitumen exists for teleost fish, but not for fauna such as marine mammals. In order to inform research needs for unconventional petroleum toxicity we conducted a comprehensive literature review of conventional petroleum toxicity on marine mammals. The common endpoints observed in conventional crude oil exposures and oil spills include hematological injury, modulation of immune function and organ weight, genotoxicity, eye irritation, neurotoxicity, lung disease, adrenal dysfunction, metabolic and clinical abnormalities related to oiling of the pelage, behavioural impacts, decreased reproductive success, mortality, and population-level declines. Based on our findings and the body of literature we accessed, our recommendations for future research include: 1) improved baseline data on PAH and metals exposure in marine mammals, 2) improved pre- and post-spill data on marine mammal populations, 3) the use of surrogate mammalian models for petroleum toxicity testing, and 4) the need for empirical data on the toxicity of unconventional petroleum to marine mammals.

Review of petroleum toxicity in marine reptiles

Worldwide petroleum exploration and transportation continue to impact the health of the marine environment through both catastrophic and chronic spillage. Of the impacted fauna, marine reptiles are often overlooked. While marine reptiles are sensitive to xenobiotics, there is a paucity of petroleum toxicity data for these specialized fauna in peer reviewed literature. Here we review the known impacts of petroleum spillage to marine reptiles, specifically to marine turtles and iguanas with an emphasis on physiology and fitness related toxicological effects. Secondly, we recommend standardized toxicity testing on surrogate species to elucidate the mechanisms by which petroleum related mortalities occur in the field following catastrophic spillage and to better link physiological and fitness related endpoints. Finally, we propose that marine reptiles could serve as sentinel species for marine ecosystem monitoring in the case of petroleum spillage. Comprehensive petroleum toxicity data on marine reptiles is needed in order to serve as a foundation for future research with newer, unconventional crude oils of unknown toxicity such as diluted bitumen.

Stereotactic body radiation therapy in patients with hepatocellular carcinoma: A mini-review

Stereotactic body radiation therapy (SBRT) is an emerging treatment for hepatocellular carcinoma. This technique results in excellent local control rates with favorable toxicity profile despite being predominantly used in heavily pretreated patients or those unsuitable for other local therapies. SBRT may be used as a sole treatment or in combination with other local therapies as well as a bridging strategy for patient awaiting liver transplants. This brief review describes current practice of SBRT with respect to radiation technique, patient selection and treatment concepts. It summarizes available evidence from retro- and prospective studies evaluating SBRT alone, SBRT in combination with other treatments and SBRT compared to other local treatment approaches.

Tiny Shuttles for Information Transfer: Exosomes in Cardiac Health and Disease

Intercellular communication mediated by exosomes, nano-sized extracellular vesicles, is crucial for preserving vascular integrity and in the development of cardiovascular and other diseases. As natural carriers of signal molecules, exosomes released from sources such as blood cells, endothelial cells, immune cells, smooth muscle cells, etc., can modify a multitude of cellular bioactivities. They do so by shuttling lipids, proteins, and nucleic acids between donor and recipient cells while circulating in body fluids and in the extracellular space. A recent surge of interest in the field of exosomal biology is in part due to the recognition that the molecules they carry can act as facilitators of both pathogenesis but can also initiate protective and rescue signaling. This mini-review describes current knowledge on exosome function in health and disease including cardiovascular disease.