Increased oxidative stress is present in brain and CSF of HIV-infected patients. There is also an accumulation of toxic substances in the CSF that are capable of inducing oxidative stress. The authors have identified several novel compounds that are capable of blocking the CSF-induced toxicity, the therapeutic potential of which is worthy of further exploration.

Axonal pathology is a key contributor to long-term disability in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS), but the mechanisms that underlie axonal pathology in MS remain elusive. Evidence suggests that axonal pathology is a direct consequence of demyelination, as we and others have shown that the node of Ranvier disassembles following loss of myelin. In contrast to the node of Ranvier, we now show that the axon initial segment (AIS), the axonal domain responsible for action potential initiation, remains intact following cuprizone-induced cortical demyelination. Instead, we find that the AIS is disrupted in the neocortex of mice that develop experimental autoimmune encephalomyelitis (EAE) independent of local demyelination. EAE-induced mice demonstrate profound compromise of AIS integrity with a progressive disruption that corresponds to EAE clinical disease severity and duration, in addition to cortical microglial reactivity. Furthermore, treatment with the drug didox results in attenuation of AIS pathology concomitantly with microglial reversion to a less reactive state. Together, our findings suggest that inflammation, but not demyelination, disrupts AIS integrity and that therapeutic intervention may protect and reverse this pathology. GLIA 2016;64:1190-1209.

Hydroxyurea, an antineoplastic agent , inhibits DNA synthesis and cell proliferation without affecting RNA and protein synthesis (Gale, 1964; Young and Hodas, 19641 Yarbro et al-0' 1965 Rosenbranz and Levy, 1965). A variety of evidence, primarily in vivo, has accumulated which suggests that the mode of action of hydroxyurea is the inhibition of the conversion of ribonucleotides to deoxyribonucleotides, a critical step in DNA synthesis (

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We hypothesized that neutralization of TNF-alpha at the time of reperfusion exerts a salubrious role on endothelial function and reduces the production of reactive oxygen species. We employed a mouse model of myocardial ischemia-reperfusion (I/R, 30 min/90 min) and administered TNF-alpha neutralizing antibodies at the time of reperfusion. I/R elevated TNF-alpha expression (mRNA and protein), whereas administration of anti-TNF-alpha before reperfusion attenuated TNF-alpha expression. We detected TNF-alpha expression in vascular smooth muscle cells, mast cells, and macrophages, but not in the endothelial cells. I/R induced endothelial dysfunction and superoxide production. Administration of anti-TNF-alpha at the onset of reperfusion partially restored nitric oxide-mediated coronary arteriolar dilation and reduced superoxide production. I/R increased the activity of NAD(P)H oxidase and of xanthine oxidase and enhanced the formation of nitrotyrosine residues in untreated mice compared with shams. Administration of anti-TNF-alpha before reperfusion blocked the increase in activity of these enzymes. Inhibition of xanthine oxidase (allopurinol) or NAD(P)H oxidase (apocynin) improved endothelium-dependent dilation and reduced superoxide production in isolated coronary arterioles following I/R. Interestingly, I/R enhanced superoxide generation and reduced endothelial function in neutropenic animals and in mice treated with a neutrophil NAD(P)H oxidase inhibitor, indicating that the effects of TNF-alpha are not through neutrophil activation. We conclude that myocardial ischemia initiates TNF-alpha expression, which induces vascular oxidative stress, independent of neutrophil activation, and leads to coronary endothelial dysfunction.