Framework for validation and implementation of in vitro toxicity tests

Summary The development and application of in vitro alternatives designed to reduce or replace the use of animals, or to lessen the distress and discomfort of laboratory animals, is a rapidly developing trend in toxicology. However, at present there is no formal administrative process to organize, coordinate, or evaluate validation activities. A framework capable of fostering the validation of new methods is essential for the effective transfer of new technologic developments from the research laboratory into practical use. This committee has identified four essential validation resources: chemical bank(s), cell and tissue banks, a data bank, and reference laboratories. The creation of a Scientific Advisory Board composed of experts in the various aspects and endpoints of toxicity testing, and representing the academic, industrial, and regulatory communities, is recommended. Test validation acceptance is contingent on broad buy-in by disparate groups in the scientific community—academics, industry, and government. This is best achieved by early and frequent communication among parties and agreement on common goals. It is hoped that the creation of a validation infrastructure composed of the elements described in this report will facilitate scientific acceptance and utilization of alternative methodologies and speed implementation of replacement, reduction, and refinement alternatives in toxicity testing.     

Loss of DNA repair mechanisms in cardiac myocytes induce dilated cardiomyopathy

Cardiomyopathy is a progressive disease of the myocardium leading to impaired contractility. Genotoxic cancer therapies are known to be potent drivers of cardiomyopathy, whereas causes of spontaneous disease remain unclear. To test the hypothesis that endogenous genotoxic stress contributes to cardiomyopathy, we deleted the DNA repair gene Ercc1 specifically in striated muscle using a floxed allele of Ercc1 and mice expressing Cre under control of the muscle-specific creatinine kinase (Ckmm) promoter or depleted systemically (Ercc1^−/D mice). Ckmm-Cre^+/−;Ercc1^−/fl mice expired suddenly of heart disease by 7 months of age. As young adults, the hearts of Ckmm-Cre^+/−;Ercc1^−/fl mice were structurally and functionally normal, but by 6-months-of-age, there was significant ventricular dilation, wall thinning, interstitial fibrosis, and systolic dysfunction indicative of dilated cardiomyopathy. Cardiac tissue from the tissue-specific or systemic model showed increased apoptosis and cardiac myocytes from Ckmm-Cre^+/-;Ercc1^−/fl mice were hypersensitive to genotoxins, resulting in apoptosis. p53 levels and target gene expression, including several antioxidants, were increased in cardiac tissue from Ckmm-Cre^+/−;Ercc1^−/fl and Ercc1^−/D mice. Despite this, cardiac tissue from older mutant mice showed evidence of increased oxidative stress. Genetic or pharmacologic inhibition of p53 attenuated apoptosis and improved disease markers. Similarly, overexpression of mitochondrial-targeted catalase improved disease markers. Together, these data support the conclusion that DNA damage produced endogenously can drive cardiac disease and does so mechanistically via chronic activation of p53 and increased oxidative stress, driving cardiac myocyte apoptosis, dilated cardiomyopathy, and sudden death.     

Molecular characterization of one of the maize polygalacturonase gene family members which are expressed during late pollen development

A gene exhibiting homology to the polygalacturonases of several species, including tomato and Oenothera, has been shown by RNA dot-blot analysis and in situ hybridization experiments to be expressed post-first microspore mitosis in maize. A 2.87 kbp section of the promoter fused to E. coli β-glucuronidase (uidA) coding sequence conferred the correct spatial and temporal expression in transgenic tobacco plants. However, low levels of expression were detected in other tissues, and in particular in the tissues surrounding the vascular branch points of leaf nodes. The maize polygalacturonase gene is one member of a highly conserved gene family. The lack of detectable expression in sporophytic tissues and the isolation of a number of related cDNAs from maize suggests that all expressed members of this family show the same spatial and temporal regulation.     

Nonparametric and semiparametric estimation with sequentially truncated survival data

In observational cohort studies with complex sampling schemes, truncation arises when the time to event of interest is observed only when it falls below or exceeds another random time, that is, the truncation time. In more complex settings, observation may require a particular ordering of event times; we refer to this as sequential truncation. Estimators of the event time distribution have been developed for simple left-truncated or right-truncated data. However, these estimators may be inconsistent under sequential truncation. We propose nonparametric and semiparametric maximum likelihood estimators for the distribution of the event time of interest in the presence of sequential truncation, under two truncation models. We show the equivalence of an inverse probability weighted estimator and a product limit estimator under one of these models. We study the large sample properties of the proposed estimators and derive their asymptotic variance estimators. We evaluate the proposed methods through simulation studies and apply the methods to an Alzheimer's disease study. We have developed an R package, seqTrun , for implementation of our method.     

Brief history of the Society for Melanoma Research: A community of clinicians,researchers, and friends

To commemorate the 20th Anniversary of the Society of Melanoma Research and the first International Melanoma Research Congress held in June of 2003, we have described in brief, how the Society for Melanoma Research (SMR) began, the purpose, goals, and governance of the SMR, and how the society has evolved to support new melanoma researchers. In celebration of the immense progress in treating melanoma patients over the last 20 years and the impact of the SMR on these advances, we have highlighted memories and insight from early SMR members and founders.     

Progress in melanoma treatment: Patient's perspectives

Upon the 20th Anniversary of the Society for Melanoma Research, we highlight the perspectives of patients aiming to help improve future experiences, outcomes, and their quality of life over the next 20 years. Five melanoma patients generously shared their inspiring and enlightening stories of diagnosis, treatment, and outcomes. Many patients had excellent medical teams that synergistically worked together to provide an accurate diagnosis, effective treatment options, and supportive care. However, it is clear that health inequities persist in communities where people of color are predominant, affecting early detection, patient experience, and outcomes. These stories shed light on the unique challenges faced by patients and how the lack of melanoma awareness and adequate resources, especially in communities of color or low socioeconomic status, can contribute to disparate outcomes in melanoma care. We expect that these stories will raise awareness about the progress in melanoma treatment but also the existent disparities in melanoma diagnosis and treatment and the importance of early detection and prevention.     

Diversity,equity, and inclusion in the melanoma research community

The inaugural Diversity and Inclusion in Science Session was held during the 2021 Society for Melanoma Research (SMR) congress. The goal of the session was to discuss diversity, equity, and inclusion in the melanoma research community and strategies to promote the advancement of underrepresented melanoma researchers. An international survey was conducted to assess the diversity, equity, and inclusion (DEI) climate among researchers and clinicians within the Society for Melanoma Research (SMR). The findings suggest there are feelings and experiences of inequity, bias, and harassment within the melanoma community that correlate with one's gender, ethnic/racial group, and/or geographic location. Notably, significant reports of inequity in opportunity, discrimination, and sexual harassment demonstrate there is much work remaining to ensure all scientists in our community experience an academic workplace culture built on mutual respect, fair access, inclusion, and equitable opportunity.     

Novel Miscanthus hybrids: Modelling productivity on marginal land in Europe using dynamics of canopy development determined by light interception

New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year⁻¹ biomass, with potential for 1.2–1.3 EJ year⁻¹ energy and 36.3–40.3 Mt year⁻¹ carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety.