The authors examined the lenticulostriate (perforating) arteries in the vascular casts of 48 middle cerebral arteries (MCA), as well as in the MRI or CT scans of 32 patients with cerebral infarcts in the MCA territory. The lenticulostriate arteries ranged between two and 12 in number, and from 80 microm to 1,400 microm in size. They originated from the main trunk, terminal trunks, bifurcation site, and/or leptomeningeal branches of the MCA, either separately or from common trunks (70.8%). The extreme variations of the supplying region of the perforators were noted in seven anatomic specimens. In addition to the basal ganglia, the genu, and the anterior limb of the internal capsule, the lenticulostriate arteries seemed to supply only the rostral portion of the superior part of the posterior limb of the capsule. The patients presented with occlusion of all the lenticulostriate arteries, individual arteries, or only their twigs. Complete occlusion of these arteries resulted in a huge central hemispheric infarct. Occlusion of an individual artery most often caused a large ganglionic-capsular infarct. The authors concluded that the lacunar infarcts usually follow occlusion of a terminal or a side branch of the lenticulostriate arteries.
In this study, we demonstrate for the first time, that a discrete metal-oxo cluster α-/β-K6P2W18O62 (WD-POM) exhibits superior performance as a computed tomography (CT) contrast agent, in comparison to the standard contrast agent iohexol. A toxicity evaluation of WD-POM was performed according to standard toxicological protocols using Wistar albino rats. The maximum tolerable dose (MTD) of 2000 mg/kg was initially determined after oral WD-POM application. The acute intravenous toxicity of single WD-POM doses (1/3, 1/5, and 1/10 MTD), which are at least fifty times higher than the typically used dose (0.015 mmol W kg−1) of tungsten-based contrast agents, was evaluated for 14 days. The results of arterial blood gas analysis, CO-oximetry status, electrolyte and lactate levels for 1/10 MTD group (80% survival rate) indicated the mixed respiratory and metabolic acidosis. The highest deposition of WD-POM (0.6 ppm tungsten) was found in the kidney, followed by liver (0.15 ppm tungsten), for which the histological analysis revealed morphological irregularities, although the renal function parameters (creatinine and BUN levels) were within the physiological range. This study is the first and important step in evaluating side effects of polyoxometalate nanoclusters, which in recent years have shown a large potential as therapeutics and contrast agents.
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