Is Testicular Germ Cell Cancer Estrogen Dependent? The Role of Endocrine Disrupting Chemicals

Testicular germ cell cancer (TGCC) is the most frequent cancer of the young male, with an increasing incidence worldwide. The pathogenesis and reasons for this increase remain unknown. However, epidemiological and experimental data have suggested that, similar to genital malformations and sperm impairment, it could result from the interaction of genetic and environmental factors including fetal exposure to endocrine-disrupting chemicals (EDCs) with estrogenic effects. In this review, we analyze the expression of classic and nonclassic estrogen receptors by TGCC cells, the way they may influence germ cell proliferation induced by EDCs, and discuss how this estrogen dependency supports the developmental and environmental hypothesis.

IMMERSIVE WAYFINDING: VIRTUAL RECONSTRUCTION AND EYE-TRACKING FOR ORIENTATION STUDIES INSIDE COMPLEX ARCHITECTURE

<p><strong>Abstract.</strong> The study presents a process of digital simulation that aims to investigate the legibility of multiple spaces in a complex architecture through architectural survey, virtual reconstruction and 3D visualization in immersive environment. The collaboration between two research institutions, one Italian and the other Chinese, developed a reconstruction of a building in the campus of the Tsinghua University of Beijing using digital tools, in order to understand the behaviours during the fruition of that space. Digital simulation in the visibility theme guarantees the possibility of testing multiple configurations and showing the impacts of the different environmental hypothesis.</p>

Characteristics of the mitochondrial and cellular uptake of MPP+, as probed by the fluorescent mimic, 4′I-MPP+

The discovery that 1-methyl-4-phenylpyridinium (MPP+) selectively destroys dopaminergic neurons and causes Parkinson’s disease (PD) symptoms in mammals has strengthened the environmental hypothesis of PD. The current model for the dopaminergic toxicity of MPP+ is centered on the uptake into dopaminergic neurons, accumulation into the mitochondria, inhibition of the complex-I leading to ATP depletion, increased reactive oxygen species (ROS) production, and apoptotic cell death. However, some aspects of this mechanism and the details of the cellular and mitochondrial accumulation of MPP+ are still poorly understood. The aim of this study was to characterize a structural and functional MPP+ mimic which is suitable to study the cellular distribution and mitochondrial uptake of MPP+ in live cells and use it to identify the molecular details of these processes to advance the understanding of the mechanism of the selective dopaminergic toxicity of MPP+. Here we report the characterization of the fluorescent MPP+ derivative, 1-methyl-4-(4’-iodophenyl)pyridinium (4’I-MPP+), as a suitable candidate for this purpose. Using this novel probe, we show that cytosolic/mitochondrial Ca2+ play a critical role through sodium-calcium exchanger (NCX) in the mitochondrial and cellular accumulation of MPP+ suggesting for the first time that MPP+ and related mitochondrial toxins may also exert their toxic effects through the perturbation of Ca2+ homeostasis in dopaminergic cells. We also found that the specific mitochondrial NCX (mNCX) inhibitors protect dopaminergic cells from the MPP+ and 4’I-MPP+ toxicity, most likely through the inhibition of the mitochondrial uptake, which could potentially be exploited for the development of pharmacological agents to protect the central nervous system (CNS) dopaminergic neurons from PD-causing environmental toxins.

Role of Environmental Pollutants in Skeletal Muscle Insulin Resistance and Mitochondrial Dysfunction

In the last decade, the incidence of diabetes in Canada has nearly doubled and is now estimated to affect one in three individuals. Type 2 diabetes (T2D) is a serious public health problem: governments and health care professional are working to control its propagation, offer better treatment alternatives and reduce its impact on patient quality of life. Insulin resistance is an early event in the development of T2D. Due to its mass and important role in the maintenance of glucose homeostasis, skeletal muscle is believed to play a central role in the development of insulin resistance. The development of this metabolic disorder is multifaceted with obesity, physical activity and diet receiving the most research interest. It is recognized that mitochondrial dysfunction, increased oxidative stress and inflammation are implicated in the development of insulin resistance in muscle. Recently, the environmental hypothesis has been advanced to explain the increased number of patients with T2D. Various persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), bisphenol A (BPA) and p, p-dichlorodiphenylchloroethane (DDT) are being investigated in their relation to T2D. However, despite the importance of skeletal muscle in the development of insulin resistance and T2D, very few studies have focused on the effect of POPs on skeletal muscle energy metabolism. This review will highlight the implication of POPs in the development of diabetes and present work being done to asses POPs’ involvement in observed metabolic disarrangements, specifically at the level of skeletal muscle.

Scratch that itch: revisiting links between self-directed behaviour and parasitological, social and environmental factors in a free-ranging primate

Different hypotheses explain variation in the occurrence of self-directed behaviour such as scratching and self-grooming: a parasite hypothesis linked with ectoparasite load, an environmental hypothesis linked with seasonal conditions and a social hypothesis linked with social factors. These hypotheses are not mutually exclusive but are often considered separately. Here, we revisited these hypotheses together in female Japanese macaques ( Macaca fuscata fuscata ) of Kōjima islet, Japan. We input occurrences of scratching and self-grooming during focal observations in models combining parasitological (lice load), social (dominance rank, social grooming, aggression received and proximity), and environmental (rainfall, temperature and season) variables. Using an information-theory approach, we simultaneously compared the explanatory value of models against each other using variation in Akaike's information criterion and Akaike's weights. We found that evidence for models with lice load, with or without environmental–social parameters, was stronger than that for other models. In these models, scratching was positively associated with lice load and social grooming whereas self-grooming was negatively associated with lice load and positively associated with social grooming, dominance rank and number of female neighbours. This study indicates that the study animals scratch primarily because of an immune/stimulus itch, possibly triggered by ectoparasite bites/movements. It also confirms that self-grooming could act as a displacement activity in the case of social uncertainty. We advocate that biological hypotheses be more broadly considered even when investigating social processes, as one does not exclude the other.