Through a series of downstream effects, the Rho GTPases inhibit NO production in the endothelium by decreasing eNOS expression and activity [4]. Less eNOS activity results in a paucity of the vasodilatory effects of NO. In essence, the Rho GTPases causes arteriolar vasoconstriction. By inhibiting their production, statins “turn off the off switch” and thus promote eNOS activity and vasodilation. Based on this theory, the expected result of statin administration would be increased cerebral blood flow with statins, which has been shown in healthy subjects [3]. In radiation vasculopathy, however, the situation is quite different from healthy controls in that the affected hemisphere has diffuse

arteriolar vasculopathy, while the contralateral hemisphere is spared this pathology. We suggest that the contradictory selleckchem finding we observed is a special result of the rule of vasodilation and an example of Caspase phosphorylation cerebral steal. At baseline, we hypothesize that there is maximal vasodilation in the pathological hemisphere. The addition of the statin could not

improve the already maximally dilated vessels on the pathological hemisphere. Statins and the addition of eNOS activity would, however, increase vessel dilation to the healthy hemisphere, shifting it from a neutral amount of vessel tone to a dilated state. This shift to a more dilated stated on the healthy hemisphere seems to exacerbate the underlying hemodynamic inequity Megestrol Acetate and causes a steal syndrome. By withdraw of statin, the healthy hemisphere tone returns to normal, and the pathological hemisphere was able to shunt more flow and improve. In healthy subjects or those with diffuse bihemispheric cerebrovascular disease, the addition of statins will likely improve vasomotor tone and augment cerebral blood flow. In the special circumstance of a patient with isolated high-grade cerebrovascular disease

in a single vascular bed, the addition of a statin may lead to a cerebral steal phenomenon. “
“The disturbance of cerebrospinal fluid (CSF) circulation in system of CSF pathways owing to the various reasons (impairment of CSF production and absorption, the mechanical block) can cause development of hydrocephalus. Depending on compensating capabilities of brain this pathology may not have clinical symptoms or, being accompanied by increase of intracranial pressure (ICP), can give a clinical picture of intracranial hypertension (ICH) syndrome. In the latter case carrying out surgical treatment – correction of the disturbed CSF circulation by means of shunting or endoscopic intervention – is required. Nevertheless in some cases, when ICH is doubtful or has temporal character, the data of clinical examination, computed tomography/magnetic resonance scanning of the brain appear insufficient for defining indications for operations.