Subsurface cistern (SSC) proliferation in Purkinje cells of the rat cerebellum in response to acute and chronic exposure to paint thinner: A light and electron microscopy study

Maternal Exposures Associated with Autism Spectrum Disorder in Jamaican Children

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with poorly understood etiology. Many maternal exposures during pregnancy and breastfeeding potentially interfere with neurodevelopment. Using data from two age- and sex-matched case-control studies in Jamaica (n = 298 pairs), results of conditional logistic regression analyses suggest that maternal exposures to fever or infection (matched odds ratio (MOR) = 3.12, 95% CI 1.74-5.60), physical trauma (MOR 2.02, 95% CI 1.01-4.05), and oil-based paints (MOR 1.99, 95% CI 1.14-3.46) may be associated with ASD. Additionally, maternal exposure to oil-based paints may modify the relationship between maternal exposure to pesticides and ASD, which deepens our understanding of the association between pesticides and ASD.

Chronic near lifetime toluene exposure in rodents does not replicate solvent abuse leukoencephalopathy in humans

Toluene is an organic solvent used in industry and as a substance of abuse. The latter situation may be associated with a leukoencephalopathy characterized by white matter atrophy, multifocal myelin loss, and macrophages that contain birefringent granular inclusions. To determine if rodents can develop the same white matter damage, we studied archived rodent brain samples from three near-lifetime toluene carcinogenicity experiments. Rats and mice were exposed to toluene via an inhalation chamber at 1200 ppm for 6.5 h daily, 5 days per week, for 103 weeks. Rats were exposed to toluene via oral gavage of 800 mg/kg, 4 days per week, for 104 weeks. In gavage-exposed brains, immunohistochemical staining was used to detect reactive astroglial and microglial changes, neuron populations, and cytochrome P450 upregulation. None of the white matter changes reported in human toluene abuse were identified in the rat or mouse brains. In a blinded analysis, a mild widespread increase in reactive microglia was detected in female rats that received toluene by gavage at 800 mg/kg. However, no significant differences were detected in neurons or astrocytes. Potential reasons for the absence of changes are discussed. We conclude that rodent studies designed to study carcinogenicity of toluene might not adequately model abuse exposure.

Time-caloric restriction inhibits the neoplastic transformation of cirrhotic liver in rats treated with diethylnitrosamine

Hepatocellular cancer is the most common type of primary liver cancer. Cirrhosis is the main risk factor that generates this malady. It has been proven that caloric restriction protocols and restricted feeding schedules are protective in experimental carcinogenic models. We tested the influence of a time-caloric restriction protocol (2 h of food access during the daytime for 18 weeks) in an experimental model of cirrhosis-hepatocarcinoma produced by weekly administration of diethylnitrosamine. Our results indicate that time-caloric restriction reduced hepatomegaly and prevented the increase in blood leukocytes promoted by diethylnitrosamine. Strikingly, time-caloric restriction preserved functional and histological characteristics of the liver in fibrotic areas compared to the cirrhotic areas of the Ad Libitum-fed group. Tumoural masses in the restricted group were well differentiated; consider a neoplastic or early stage of HCC. However, time-caloric restriction enhanced collagen deposits. With regard to the cancerous process, food restriction prevented systemic inflammation and an increase in carcinoembryonic antigen, and it favoured the occurrence of diffuse multinodular tumours. Histologically, it prevented hepatocyte inflammation response, the regenerative process, and neoplastic transformation. Time-caloric restriction stimulated circadian synchronization in fibrotic and cancerous liver sections, and it increased BMAL1 clock protein levels. We conclude that time-caloric restriction prevents fibrosis from progressing into cirrhosis, thus avoiding chronic inflammation and regenerative processes. It also prevents, probably through circadian entrainment and caloric restriction, the neoplastic transformation of tumoural lesions induced by diethylnitrosamine.