Early diagnosis of Parkinson's disease (PD) in nonsymptomatic patients is a key issue. An increased echogenicity of the substantia nigra (SN) was found previously in Parkinsonian patients and in a low percentage of healthy adults. These nonsymptomatic subjects also showed a reduced 18F-dopa uptake in striatum, suggesting a preclinical injury of the nigrostriatal system that could later proceed into PD. To investigate the ability of ultrasonography to detect markers of SN degeneration, such as iron deposition and neuromelanin depletion, we scanned postmortem brains from normal subjects at different ages by ultrasound and measured the echogenic area of the SN. The SN was then dissected and used for histological examinations and determination of iron, ferritin, and neuromelanin content. A significant positive correlation was found between the echogenic area of the SN and the concentration of iron, H- and L-ferritins. Multivariate analysis carried out considering the iron content showed a significant negative correlation between echogenicity and neuromelanin content of the SN. In PD, a typical loss of neuromelanin and increase of iron is observed in this brain area. The finding of a positive correlation between iron and ferritin levels and a negative correlation of neuromelanin content with the area of echogenicity at the SN could therefore provide an interesting basis for diagnosis and therapeutic follow-up studies in PD.

Vascular dementia (VaD) is the second most common type of dementia after Alzheimer’s disease (AD), characterized by progressive cognitive impairment, memory loss, and thinking or speech problems. VaD is usually caused by cerebrovascular disease, during which, cerebrovascular endothelial cells (CECs) are vulnerable. CEC dysfunction occurs before the onset of VaD and can eventually lead to dysregulation of cerebral blood flow and blood–brain barrier damage, followed by the activation of glia and inflammatory environment in the brain. White matter, neuronal axons, and synapses are compromised in this process, leading to cognitive impairment. The present review summarizes the mechanisms underlying CEC impairment during hypoperfusion and pathological role of CECs in VaD. Through the comprehensive examination and summarization, endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) signaling pathway, Ras homolog gene family member A (RhoA) signaling pathway, and CEC-derived caveolin-1 (CAV-1) are proposed to serve as targets of new drugs for the treatment of VaD.

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We analyzed trace metals in frozen brain tissue of several subcortical nuclei from 3 patients with primary adult‐onset dystonia and 10 control subjects. Copper levels were significantly increased in the globus pallidus and putamen of patients with dystonia. A slight increase in manganese content was identified in the putamen and thalamus of patients with dystonia. Our findings show for the first time an accumulation of trace metals in the lentiform nuclei in patients with primary dystonia, which may play a pathogenetic role in primary dystonia and may explain recent ultrasound and magnetic resonance imaging findings. Ann Neurol 1999;46:260–263

Abstract. Amyloid β (Aβ) toxicity has been implicated in cell death in the hippocampus, but its specific mechanisms are poorly understood. In this study, Aβ-induced cell death was investigated in organotypic hippocampal slice cultures (OHCs) that were cultured for various periods in vitro. There were no obvious histological differences among slices cultured for 3 to 7 weeks in vitro. Although there was little neurotoxicity after treatment with Aβ 25-35 in OHCs cultured for relatively shorter periods (3 -5 weeks), age-dependent cell death was evident in OHCs cultured for relatively longer periods (6 -7 weeks) after exposure to Aβ 25-35 . In OHCs cultured for 7 weeks, S-allyl-L-cysteine (SAC), a component of aged garlic extract, protected the cells in areas CA1 and CA3 and the dentate gyrus from Aβ 25-35 -induced toxicity. The immunoreactivity of cleaved caspase-12 was increased whereas that of glucose-regulated protein 78 was not altered after exposure to Aβ [25][26][27][28][29][30][31][32][33][34][35] . The increases in the cleaved caspase-12 were also reversed by simultaneously applied SAC. These results suggest that OHCs cultured for relatively longer periods are more susceptible to Aβ-induced toxicity and that the Aβ-induced cell death involves caspase-12-dependent pathways. It is also suggested that SAC is able to protect against the Aβ-induced neuronal cell death through the inhibition of the caspase-12-dependent pathway.