Aralar is a mitochondrial calcium-regulated aspartate-glutamate carrier mainly distributed in brain and skeletal muscle, involved in the transport of aspartate from mitochondria to cytosol, and in the transfer of cytosolic reducing equivalents into mitochondria as a member of the malate-aspartate NADH shuttle. In the present study, we describe the characteristics of aralardeficient (Aralar ؊/؊ ) mice, generated by a gene-trap method, showing no aralar mRNA and protein, and no detectable malate-aspartate shuttle activity in skeletal muscle and brain mitochondria. Aralar ؊/؊ mice were growth-retarded, exhibited generalized tremoring, and had pronounced motor coordination defects along with an impaired myelination in the central nervous system. Analysis of lipid components showed a marked decrease in the myelin lipid galactosyl cerebroside. The content of the myelin lipid precursor, N-acetylaspartate, and that of aspartate are drastically decreased in the brain of Aralar ؊/؊ mice. The defect in N-acetylaspartate production was also observed in cell extracts from primary neuronal cultures derived from Aralar ؊/؊ mouse embryos. These results show that aralar plays an important role in myelin formation by providing aspartate for the synthesis of N-acetylaspartate in neuronal cells.
Aims: To describe the clinical and histopathological findings in a patient with polypoidal choroidal vasculopathy. Methods: A 76 year old Japanese man had a discrete, orange-red lesion of 1 disc diameter in the macula, with the fluorescein and indocyanine green angiographic and optical coherence tomographic findings compatible with polypoidal choroidal vasculopathy. He underwent a surgical removal of the macular lesion, followed by light and electron microscopic examinations. Results: The histopathological examination revealed that the specimen consisted of degenerated retinal pigment epithelium-Bruch's membrane-choriocapillaris complex and inner choroid. A tortuous, unusually dilated venule was present adjacent to an arteriole with marked sclerotic changes, appearing to form arteriovenous crossing. These vessels seemed to represent native inner choroidal vessels, and had haemorrhage per diapedesis. Blood cells and fibrin filled the lumina of the vessels and accumulated in the extravascular spaces, indicating vascular stasis. Conclusion: Hyperpermeability and haemorrhage due to stasis of a dilated venule and an arteriole involved by sclerosis at the site where they cross in the inner choroid might cause oedema and degeneration of the tissue. Voluminous accumulation of blood cells and fibrin might generate elevation of tissue pressure sufficient to displace the weakened lesion anteriorly. The result suggests that the polypoidal vessels in this case represent abnormality in the inner choroidal vasculature. P olypoidal choroidal vasculopathy (PCV) is a distinct clinical entity characterised by its morphological features 1-10 -aneurysmal dilations seen as reddish-orange, spheroidal, polyp-like structures or polypoidal vascular lesions at the termination of a network of large choroidal vessels. Patients with this disorder are known to be at risk of having recurrent serous and haemorrhagic detachments of both the retinal pigment epithelium (RPE) and the neurosensory retina. This appears to be a common presentation of macular disease in middle and late life in east Asia. 8 The vascular abnormality appears to exist external to the RPE, but only a few cases have been studied histopathologically [11][12][13] and the location and feature of the pathological vessels are controversial. Concerning the origin of the vessels, there are two hypotheses: a variant of choroidal neovascularisation 5-13 v abnormalities in the inner choroidal vessels.14 15 This study reports the clinicopathological correlation in a case of PCV whose macular lesion was removed and examined by light and electron microscopy.
PATIENT AND METHODS
Case reportA 76 year old Japanese man presented with blurred left eye vision for 2 weeks. He lost right eye central vision in the fourth decade of life. He had no systemic disorder. He had not received treatment to either eye. Best corrected visual acuity was 20/200 with the right eye and 20/250 in the left. Fundus examination of the right eye revealed a small atrophic choroidal scar and a few drusen in the poster...
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