The mitochondrial protein frataxin is downregulated in hemodialysis patients.

BACKGROUND: The mitochondrial protein frataxin regulates iron metabolism for heme and iron sulfur cluster synthesis in the mitochondria and could be associated with the regulation of oxidative stress. To clarify the expression of frataxin and its association with uremia, we evaluated the mRNA and protein levels of frataxin in the polymorphonuclear leukocytes (PMNLs) of patients on hemodialysis (HD). METHODS: Uremic patients on HD (n = 18) and healthy control subjects (n = 18) were investigated. PMNLs were isolated by differential centrifugation. The mRNA levels of frataxin in isolated leukocytes were quantified by TaqMan real-time polymerase chain reaction. Frataxin protein expression in the cell lysate was evaluated using SDS-polyacrylamide gel electrophoresis and Western blotting. RESULTS: The frataxin/glyceraldehyde-3-phosphate dehydrogenase mRNA ratio in PMNLs from uremic patients was significantly lower than that in control subjects. Frataxin protein expression in uremic patients was also significantly lower than that in controls. Multiple regression analysis showed that frataxin mRNA levels were independently associated with the serum levels of both the oxidative stress marker malondialdehyde and the proinflammatory cytokine tumor necrosis factor-α. CONCLUSION: The downregulation of frataxin seems to be linked with uremic status, which is usually associated with chronic inflammation and the acceleration of oxidative stress. Mitochondrial iron regulation may play a role in several comorbidities and in the poor prognosis in uremic patients. Further investigation is needed to elucidate whether reduced frataxin levels are linked to the pathological status of uremic patients and whether uremic substances affect frataxin expression.

Pure dysarthria due to an insular infarction.

Cortical infarction presenting with pure dysarthria is rarely reported. Previous studies have reported pure dysarthria due to cortical stroke at the precentral gyrus or middle frontal gyrus. We report a 72-year-old man who developed pure dysarthria caused by an acute cortical infarction in the insular cortex. The role of the insula in language has been difficult to assess clinically because of the rarity of pure insular strokes. Our patient showed pure dysarthria without aphasia, indicating that pure dysarthria can be the sole manifestation of insular infarctions.

Pure monoparesis of the leg due to cerebral infarctions: a diffusion-weighted imaging study.

Pure monoparesis of the leg due to cerebral infarction is rare compared to that of the hand. The anterior cerebral artery (ACA) territory is the most common lesion site in leg monoparesis, but diffusion-weighted (DW) MRI has not commonly been used for lesion detection. The purpose of this study was to use DW MRI to evaluate the radiological correlation with lesion location in patients presenting with pure leg monoparesis. We retrospectively studied six cerebral infarct patients with pure leg monoparesis who had undergone DW MRI. Patients were scanned within 3 days of symptom onset. DW MRI identified lesions in the posterior limb of the internal capsule (PLIC) in two patients, in the corona radiata (two patients), in the subcortical white matter of the posterior frontal lobe (one patient), and in the frontal and parietal cortex, including the paracentral lobule and precuneus (one patient). The two patients with PLIC infarctions had characteristic linear infarction abnormalities along the long axis of the internal capsule. Corona radiata infarction were located posteriorly, and the two subcortical and cortical infarction were thought to be in the territory of the ACA. We thus concluded that in leg monoparesis due to infarctions, lesions may be located in the PLIC, corona radiata, or in the ACA territory. Recently, magnetic resonance tractography has shown that foot fibres of the corticospinal tract in the PLIC somatotopically may be posteromedial to hand fibres along the short axis of the internal capsule, rather than posterolateral along the long axis as has been thought. Thus, damage along the long axis of the PLIC by linear infarctions can cause pure monoparesis of the leg.

Catalytic atropo-enantioselective reduction of biaryl lactones to axially chiral biaryl compounds.

The atropo-enantioselective borohydride reduction with dynamic kinetic resolution of biaryl lactones was catalyzed by an optically active beta-ketoiminatocobalt(II) complex to afford optically active biaryl compounds. Chiral HPLC analysis of the starting biaryl lactones was performed at various temperatures to determine suitable reaction conditions for dynamic kinetic resolution. Various types of axially chiral biaryl compounds were obtained with high enantioselectivity.

Catalytic enantioselective borohydride reduction of ortho-fluorinated benzophenones.

[reaction: see text] In the presence of the optically active ketoiminatocobalt(II) complexes, the enantioselective borohydride reduction of benzophenones was successfully completed. The fluorine atom on the ortho position of the benzophenone and aryl ketones proved effective for obtaining high enantioselectivities. The combined use of modified lithium borohydride afforded the corresponding benzhydrols and arylcarbinols in high yield and high enantioselectivity (88-96% ee).

Visualization of the S-locus region in Ipomoea trifida: toward positional cloning of self-incompatibility genes.

Self-incompatibility (SI) in Ipomoea trifida is regulated by a single S locus with multiple alleles. Identification of SI genes in the S -locus region by positional cloning is one of the most important goals for understanding sexual reproduction in this species. Despite our intensive efforts to construct bacterial artificial chromosome (BAC) contigs covering the S -locus region, a gap was observed in the core region of the potential S locus. In order to confirm the physical linkage of two non-overlapping BAC contigs in the S -locus region and to determine the size of the gap between them, fluorescence in-situ hybridization (FISH) was performed on mitotic chromosomes and extended DNA fibres using previously isolated S -linked BAC clones as probes. The information obtained from this work would be useful for molecular cloning of the SI genes by a chromosome walking approach. In addition, we showed that strong suppression of recombination in the S locus was not related to the centromere because the S locus was mapped to one end of a chromosome.