Search

BACKGROUND: Azoxystrobin (AZ) is a broad-spectrum strobilurin fungicide that is used in agriculture and was recently added to mold- and mildew-resistant wallboards. AZ was found to have toxic effects in animals at embryonic stages and was listed as a frontline target for biomonitoring in children. OBJECTIVES: This study investigated exposure to AZ in pregnant women and young children, whether AZ could be transferred from an exposed mother to offspring, and whether AZ or one of its primary metabolites, AZ-acid, was neurotoxic in vitro. METHODS: We quantified AZ-acid, a sensitive indicator of AZ exposure, in urine samples collected from 8 pregnant women (12 urine samples) and 67 children (40-84 months old; 96 urine samples) with high-resolution mass spectrometry. Gestational and lactational transfer was assessed in C57Bl/6 mice. Neurotoxicity of AZ and AZ-acid was investigated in vitro with mouse cortical neuron cultures. RESULTS: AZ-acid was present above the limit of quantification (formula presented ) in 100% of the urine samples from pregnant women and in 70% of the urine samples from children, with median concentration of 0.10 and formula presented , and maximal concentration of 2.70 and formula presented , respectively. Studies in mice revealed that AZ transferred from the mother to offspring during gestation by crossing the placenta and entered the developing brain. AZ was also transferred to offspring via lactation. High levels of cytotoxicity were observed in embryonic mouse cortical neurons at concentrations that modeled environmentally relevant exposures. DISCUSSION: Our study suggested that pregnant women and children were exposed to AZ, and at least 10% of the children (2 out of 20 that were evaluated at two ages) showed evidence of chronic exposure. Future studies are warranted to evaluate whether chronic AZ exposure affects human health and development.

Research with rodents is crucial for expanding our understanding of genetic and environmental risk factors for neurodevelopmental disorders (NDD). However, there is growing concern about the number of animal studies that are difficult to replicate, potentially undermining the validity of results. These concerns have prompted funding agencies and academic journals to implement more rigorous standards in an effort to increase reproducibility in research. However, these standards fail to address a major source of variability in rodent research brought on by the “litter effect,” the fact that rodents from the same litter are phenotypically more similar to one other than rodents from different litters of the same strain. We show that the litter effect accounts for 30–60% of the variability associated with commonly studied phenotypes, including brain, placenta, and body weight. Moreover, we show how failure to control for litter-to-litter variation can mask a phenotype in Chd8V986*/+ mice that model haploinsufficiency of CHD8, a high-confidence autism gene. Thus, if not properly controlled, the litter effect has the potential to negatively influence rigor and reproducibility of NDD research. While efforts have been made to educate scientists on the importance of controlling for litter effects in previous publications, our analysis of the recent literature (2015–2020) shows that the vast majority of NDD studies focused on genetic risks, including mutant mouse studies, and environmental risks, such as air pollution and valproic acid exposure, do not correct for litter effects or report information on the number of litters used. We outline best practices to help scientists minimize the impact of litter-to-litter variability and to enhance rigor and reproducibility in future NDD studies using rodent models.

Background: Chromodomain helicase DNA-binding protein 8 (Chd8) is a high-confidence risk gene for autism spectrum disorder (ASD). However, how Chd8 haploinsufficiency impairs gene expression in the brain and impacts behavior at different stages of life is unknown. Methods: We generated a mutant mouse line with an ASD-linked loss-of-function mutation in Chd8 (V986; stop codon mutation). We examined the behavior of Chd8 mutant mice along with transcriptional changes in the cerebral cortex as a function of age, with a focus on one embryonic (E14.5) and three postnatal ages (1, 6, and 12 months). Results: Chd8 V986/+ mutant mice displayed macrocephaly, reduced rearing responses and reduced center time in the open field, and enhanced social novelty preference. Behavioral phenotypes were more evident in Chd8 V986/+ mutant mice at 1 year of age. Pup survival was reduced in wild-Type x Chd8 V986/+ crosses when the mutant parent was female. Transcriptomic analyses indicated that pathways associated with synaptic and neuronal projections and sodium channel activity were reduced in the cortex of embryonic Chd8 V986/+ mice and then equalized relative to wild-Type mice in the postnatal period. At 12 months of age, expression of genes associated with endoplasmic reticulum (ER) stress, chaperone-mediated protein folding, and the unfolded protein response (UPR) were reduced in Chd8 V986/+ mice, whereas genes associated with the c-MET signaling pathway were increased in expression. Limitations: It is unclear whether the transcriptional changes observed with age in Chd8 V986/+ mice reflect a direct effect of CHD8-regulated gene expression, or if CHD8 indirectly affects the expression of UPR/ER stress genes in adult mice as a consequence of neurodevelopmental abnormalities. Conclusions: Collectively, these data suggest that UPR/ER stress pathways are reduced in the cerebral cortex of aged Chd8 V986/+ mice. Our study uncovers neurodevelopmental and age-related phenotypes in Chd8 V986/+ mice and highlights the importance of controlling for age when studying Chd8 haploinsufficient mice.

Moral philosophy plays a fundamental role, together with political philosophy and Jurisprudence, in Finnis’ argument present in his two editions of Natural Law and Natural Rights, to answer the question of how natural rights are based on natural law. Finnis’ explanation of natural law and its functioning is inspired in some relevant texts of Aquinas; however, the roots and reasonings of both authors are diverse here. The first edition presents a moral philosophy proposing the interaction between two types of principles: basic human goods and the requirements of one of them (practical reasonableness). The second edition introduces a new moral principle, called «integral human fulfillment», to moderate the interplay of the said principles. This work explains why the moral assumptions under the first edition were restrictive and shown the insufficiency for human goods to fill the teleological perspective of morality. Likewise, I explain the doctrinal evolution of the concept of integral human fulfilment in the author’s work as well as the difficulties deriving of the introduction of the new moral «guide» (formally recognized from 1987 on), within an existing theory. I have focused on the following possibly problematic aspects of the new principle: the use of denominations with different meanings as synonyms (flourishing, fulfillment, realization.../ end, objective, goal, good, not good, key premise, master principle of morality, ideal, precept...), its not precise comparison with the thomistic beatitudo imperfecta, its problematic assembling with the «evident» practical principles as explained in the first edition, the circularity of the system, and the possible doubts about the preceptive role of the ideal of the integral human flourishing, by assuming that it does not involve, necessariliy, the idea of an end. La filosofía moral ocupa una parte fundamental, junto con la filosofía política y la filosofía del derecho (Jurisprudence), de la explicación que propone Finnis en sus dos ediciones de Natural Law and Natural Rights para dar respuesta a la cuestión de cómo se fundamentan los derechos naturales en la ley natural. La explicación de Finnis acerca de la ley natural y su operación está inspirada en algunos textos importantes de T. de Aquino; no obstante, las raíces y razonamientos de ambos autores son distintos. En la primera edición, la filosofía moral presentada propone la interacción entre dos tipos de principios: los bienes humanos básicos y las exigencias de uno de ellos (la razonabilidad práctica). En la segunda, Finnis introduce un principio moral para modular dicha interacción, denominado «plenitud humana integral». En este trabajo se explica por qué el planteamiento moral presente en la primera edición era restrictivo y evidenciaba la insuficiencia de los bienes humanos para lograr un espectro teleológico capaz de para orientar la moralidad. Asimismo, se describe la evolución del concepto de la plenitud humana integral en la producción del autor y se señalan las dificultades asociadas a la recepción de la nueva «guía» moral (formalmente reconocida a partir de 1987) dentro del conjunto doctrinal ya existente. Se focaliza la atención en las dificultades siguientes: el uso de denominaciones con significados diversos como si fueran sinónimos (florecimiento, plenitud, realización.../fin, objetivo, bien, no bien, exigencia, key premise, principio maestro de la moral, ideal, precepto...), la imprecisa equiparación con la beatitudo imperfecta tomista, el problemático encaje con los principios prácticos señalados como autoevidentes en la primera edición, la circularidad del sistema y la posible falta de virtualidad preceptiva en la noción de la plenitud humana integral por no presentarse, necesariamente, como un fin.