To investigate the significance of peroxynitrite‐mediated oxidative damage in the pathogenesis of sporadic amyotrophic lateral sclerosis (SALS), the concentrations of 3‐nitrotyrosine and tyrosine in the cerebrospinal fluid (CSF) of patients with SALS were determined. The concentration of 3‐nitrotyrosine and the 3‐nitrotyrosine/ tyrosine ratio in patients with SALS were approximately seven times those of controls. Thus, the present findings in living patients provide in vivo evidence for a possible role of peroxynitrite, a mediator of oxidative stress, and increased nitration of tyrosine residues in the pathogenesis of SALS. Ann Neurol 1999;46:129–131
The mechanism by which tooth loss accelerates spatial memory impairment is unknown. The purpose of this study was to test the hypothesis that tooth loss affects trkB-mRNA levels and leads to an accelerated decrease in the hippocampal cell density in rats. A radial maze was used to evaluate the spatial memory of male Wistar rats that were categorized based on the number of extracted molar teeth. Number of hippocampal pyramidal cells and the trkB-mRNA expressions in the amygdala, perirhinal cortex, thalamus, and the hippocampal CA1, CA3, and CA4 areas, were evaluated using molecular biological techniques. Seven weeks after tooth extraction, maze performance was significantly lower in each tooth loss group than in the control group, and the number of extracted teeth was inversely proportional to the induction of the trkB-mRNA and the hippocampal cell density. The average weight of rats increased by controlled feeding throughout the experiment without showing a significant difference between the control and experimental groups. The results indicated that, in rats, the spatial memory-linked trkB-mRNA was reduced in association with the tooth loss; this supports the hypothesis and suggests that teeth have a role in the prevention of spatial memory impairment.
We reviewed 165 cases of traumatic tympanic membrane perforation treated in the last 9 years (2000-2008). Of these, 103 sustained direct injury and 62 indirect injury. Ear picking accounted for 90.3% of direct injuries. Perforation size followed the classification of Yoshikawa, with Grade I perforation the most common, according for 129 (78.2%). The anteroinferior quadrant perforation site was the most common, with 98 (59.4%). Of the 165, 66 were lost during followup. Of the remaining 99, perforations closed spontaneously in 85 (85.9%), within a mean 25.9 days. Tympanoplasty was done in 14, in whom postoperative hearing improved in 12. The remaining 2 had ossicular fractures associated with perilymph fistula. In the 14 undergoing surgery, tympanic membrane perforation relapsed in 4 and 2 developed cholesteatoma as tympanoplasty sequelae.
The concentration of the nitric oxide (NO) metabolites nitrite (NO2-) and nitrate (NO3-) in the cerebrospinal fluid from patients with Alzheimer's disease (AD), vascular dementia of the Binswanger type (VDBT) or multiple small infarct type (MSID), and controls were determined using high performance liquid chromatography. The nitrite concentration was significantly higher in VDBT/MSID patients than in controls (p < 0.005). The nitrate concentration and the combined nitrite and nitrate concentration was significantly higher in both AD (p < 0.05) and VDBT/MSID (p < 0.001) patients than in controls, with these concentrations being significantly greater in VDBT/MSID than AD patients (p < 0.005). The combined nitrite and nitrate concentration significantly decreased as the severity of dementia progressed in AD (rs=0.70, p < 0.01), but remained elevated in all stages of VDBT/MSID. These results suggest that NO production or oxidation in the brain increases in the early stage of AD and then decreases as neuronal cell loss progresses, but increases throughout the course of disease in VDBT/MSID, which may in part contribute to neuronal degeneration in both conditions.
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