Rats were deprived of sleep for 96 h by the platform technique and total glutathione (GSHtau) levels were measured in seven different brain areas. Glutathione levels were found to be significantly reduced in the hypothalamus of sleep-deprived animals when compared with large platform (-18%) or home cage (-31%) controls. Deprived rats also had reduced GSHtau levels in thalamus compared with home cage controls only. Glutathione levels did not differ among the three groups in any of the other brain areas examined. These results indicate that specific brain areas may be differentially susceptible to oxidative stress after sleep deprivation. The apparent vulnerability of the hypothalamus to these effects may contribute to some of the functional effects of sleep deprivation.

Induction of adult rat bone marrow mesenchymal stem cells (MSC) by means of chemical compounds (β-mercaptoethanol, dimethyl sulfoxide and butylated hydroxyanizole) has been proposed to lead to neuronal transdifferentiation, and this protocol has been broadly used by several laboratories worldwide. Only a few hours of MSC chemical induction using this protocol is sufficient for the acquisition of neuronal-like morphology and neuronal protein expression. However, given that cell death is abundant, we hypothesize that, rather than true neuronal differentiation, this particular protocol leads to cellular toxic effects. We confirm that the induced cells with neuronal-like morphology positively stained for NF-200, S100, β-tubulin III, NSE and MAP-2 proteins. However, the morphological and molecular changes after chemical induction are also associated with an increase in the apoptosis of over 50% of the plated cells after 24 h. Moreover, increased intracellular cysteine after treatment indicates an impairment of redox circuitry during chemical induction, and in vitro electrophysiological recordings (patch-clamp) of the chemically induced MSC did not indicate neuronal properties as these cells do not exhibit Na+ or K+ currents and do not fire action potentials. Our findings suggest that a disruption of redox circuitry plays an important role in this specific chemical induction protocol, which might result in cytoskeletal alterations and loss of functional ion-gated channels followed by cell death. Despite the neuronal-like morphology and neural protein expression, induced rat bone marrow MSC do not have basic functional neuronal properties, although it is still plausible that other methods of induction and/or sources of MSC can achieve a successful neuronal differentiation in vitro.

Homocysteine (Hcy) is converted to cysteine or is remethylated to methionine by methylenetetrahydrofolate reductase (MTHFR). MTHFR plays a central role in the metabolism of folate. Two common polymorphisms in the MTHFR gene (C677T and A1298C) have been described and studies suggest that these polymorphisms are positively associated with the occurrence of spina bifida (SB). Among Brazilians, the incidence of 677T allele homozygosity is 4%. We compared Hcy levels with the genotypes obtained for the mutations C677T and A1298C in the gene MTHFR. Levels of plasma Hcy were higher in children with SB than in controls (average 7.95 vs. 5.55 (micromol/L); P < 0.001). There was no significant difference in the levels of Hcy for these children's mothers and controls (average 7.76 vs. 8.36 (micromol/L); P = 0.27). Eighty one (61.8%) of the affected children were white and 50 (38.2%) were non-white. A similar ratio was observed in the mothers. In the control group, 51 children (40.5%) were white and 75 (59.5%) were non-white, and 52 mothers (41.3%) were white and 74 (58.7%) were non-white. There was no significant difference in the homozygous frequency for the mutated allele 677T among different racial groups. We obtained a prevalence of TT homozygosity of 10/131 (7.64%) in affected children and 13/126 (10.32%) in controls. With respect to the mutation A1298C, the homozygous prevalence for the wild allele was greater among non-white individuals than in white individuals both in case and control groups. Hyperhomocysteinemia is a risk factor for SB. However, in our population, the increase in plasma levels of Hcy is not explained by the presence of the homozygous TT. It is possible that low folic acid intake combined with other genetic factors plays a more important role in the cause of this disease.

Sleep deficit and related disorders are becoming increasingly prevalent in modern life and an extensive literature has documented that acute or chronic sleep deprivation can lead to several physiological consequences. Here, we evaluated the effects of sleep deprivation on hematopoietic composition of either bone marrow or peripheral blood. Mice were subjected to paradoxical sleep deprivation (PSD) for 72 h by modified multiple platform method, with or without an additional sleep recovery (SR) period of 10 days. PSD decreased total cellularity of the bone marrow and peripheral blood concomitantly. Subsequent analysis of cell composition showed that absolute number of hematopoietic stem/progenitor cells and colony-forming units was decreased. Moreover, the absolute number of granulocytes and monocytes in bone marrow was reduced in PSD group. These alterations were paralleled by an accumulation of neutrophils and monocytes in peripheral blood. PSD also induced lymphopenia in the circulation. To the best of our knowledge, this is the first study that demonstrates the importance of sleep on the hematopoietic microenvironment and provides new insights into the relationship between sleep and the immune system.

Hyperhomocysteinemia has been associated with pathological and stressful conditions and is a risk factor for cardiovascular disease. Since sleep deprivation is a stressful condition that is associated with disruption of various physiological processes, we investigated whether it would also be associated with increases in plasma homocysteine levels. Further, since hyperhomocysteinemia may promote oxidative stress, and we had previously found evidence of oxidative stress in brain following sleep deprivation, we also searched for evidence of systemic oxidative stress by measuring glutathione and thiobarbituric acid reactive substance levels. Rats were sleep deprived for 96 h using the platform technique. A group was killed after sleep deprivation and another two groups were allowed to undergo sleep recovery for 24 or 48 h. Contrary to expectation, plasma homocysteine was reduced in sleep-deprived rats as compared with the control group and did not revert to normal levels after 24 or 48 h of sleep recovery. A trend was observed towards decreased glutathione and increased thiobarbituric acid reactive substance levels in sleep-deprived rats. It is possible that the observed decreases in homocysteine levels may represent a self-correcting response to depleted glutathione in sleep-deprived animals, which would contribute to the attenuation of the deleterious effects of sleep deprivation.