Journal of the neurological sciences
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Brain ischemia and reperfusion engage multiple independently-fatal terminal pathways involving loss of membrane integrity in partitioning ions, progressive proteolysis, and inability to check these processes because of loss of general translation competence and reduced survival signal-transduction. Ischemia results in rapid loss of high-energy phosphate compounds and generalized depolarization, which induces release of glutamate and, in selectively vulnerable neurons (SVNs), opening of both voltage-dependent and glutamate-regulated calcium channels. This allows a large increase in cytosolic Ca(2+) associated with activation of mu-calpain, calcineurin, and phospholipases with consequent proteolysis of calpain substrates (including spectrin and eIF4G), activation of NOS and potentially of Bad, and accumulation of free arachidonic acid, which can induce depletion of Ca(2+) from the ER lumen. ⋯ This picture argues powerfully that, for therapy of brain ischemia and reperfusion, the concept of single drug intervention (which has characterized the approaches of basic research, the pharmaceutical industry, and clinical trials) cannot be effective. Although rigorous study of multi-drug protocols is very demanding, effective therapy is likely to require (1) peptide growth factors for early activation of survival-signaling pathways and recovery of translation competence, (2) inhibition of lipid peroxidation, (3) inhibition of calpain, and (4) caspase inhibition. Examination of such protocols will require not only characterization of functional and histopathologic outcome, but also study of biochemical markers of the injury processes to establish the role of each drug.
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Case Reports
Dialysis-related spinal canal stenosis: a clinicopathological study on amyloid deposition and its AGE modification.
Three cases operated for spinal canal stenosis induced by dialysis-related amyloidosis (DRA) were investigated clinicopathologically. Cases were all-male, and had undergone hemodialysis around 20 years. In two cases, cervical plain X-rays showed only minor spondylotic changes. ⋯ These findings suggest that beta2m accumulation and inflammatory reaction finally promote destruction of connective tissues. MRI, CT and/or myelography are necessary for diagnosing spinal canal stenosis accompanied by DRA. In conclusion, we propose a more comprehensive concept of dialysis-related spinal canal stenosis, which includes both DSA and myeloradiculopathy induced by extradural thickness.
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We evaluated the alexia and agraphia of three patients with different lesions using Japanese kanji (morphograms) and kana (phonograms) and made a lesion-to-symptom analysis. Patient 1 (pure alexia for both kanji and kana and minor agraphia for kanji after a fusiform lesion) made more paragraphic errors for kanji, whereas patient 2 (alexia with agraphia for kanji after a posterior inferior temporal lesion) showed severe reading and writing disturbances and more agraphic errors for kanji. ⋯ We believe that pure alexia (patient 1) results from a disconnection between the medial fusiform gyrus and posterior inferior temporal area (the lateral fusiform and inferior temporal gyri), whereas alexia with agraphia for kanji (patient 2), corresponding to lexical agraphia in Western countries, results from damage to the posterior inferior temporal area, in which whole-word images of words are thought to be stored. Furthermore, restricted lesion in the angular gyrus (patient 3) does not produce alexia; the alexic symptom of "angular" alexia with agraphia may be the result of damage to the adjacent lateral occipital gyri.
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Differential diagnosis between idiopathic Parkinson's disease (PD) and multiple system atrophy (MSA) is often difficult in early disease stages. Since MSA is misdiagnosed as PD in more than 20% of the early stages, there is need for methods refining the differentiation of the two disease entities. In PD postganglionic involvement of the autonomic nervous system (ANS) predominates whereas in MSA the ANS is mainly affected in its preganglionic structures. The functional integrity of postganglionic cardiac sympathetic neurons can be investigated using I-123-metaiodobenzylguanidine-single photon emission computed tomography (MIBG-SPECT). ⋯ Our study shows that MIBG-SPECT identifies autonomic cardiac dysfunction in very early stages of both, PD and MSA. More importantly, the technique facilitates differentiation of MSA and PD in the early stages. The different pathology with prominent peripheral, postganglionic sympathetic dysfunction in PD and primarily central and preganglionic lesions in MSA accounts for a lower MIBG uptake in PD compared to MSA patients.
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Cranial magnetic resonance images (MRI) of the cerebral areas of 40 patients with multiple system atrophy (MSA) and of 61 age-matched controls were analyzed. The cerebral area of MSA patients was 131. 95+/-15.89 cm(2) (mean+/-S. D.), which was significantly smaller than that of normal controls at 149.01+/-10.93 cm(2) (P<0.0001). ⋯ There were no significant differences within the MSA subtypes or between gender. The progression of cerebral atrophy in MSA correlated more with duration (r=-0.634) than age (r=-0.421). We conclude that MRI findings throughout the course of MSA suggest progressive cerebral atrophy, which is common in all subtypes and reflects duration of the disease rather than age.