Age-related changes in microarchitecture and mineralization of cancellous bone in the porcine mandibular condyle

The mandibular condyle is considered a good model for developing cancellous bone because of its rapid growth and high rate of remodeling. The aim of the present study was to analyze the simultaneous changes in microarchitecture and mineralization of cancellous bone during development in a three-dimensional fashion. Eight mandibular condyles of pigs aged 8 weeks prepartum to 108 weeks postpartum were scanned using microCT with an isotropic spatial resolution of 10 microm. The number of trabeculae decreased during development, whereas both the trabecular thickness and the distance between the trabeculae increased. The bone surface to volume ratio decreased during development, possibly limiting the amount of (re)modeling. Both the mean degree of mineralization and intratrabecular differences in mineralization between the surfaces and cores of trabecular elements increased during development. The trabecular surfaces were more highly mineralized in the older condyles compared to the younger ones. Together with the observed decrease in the relative size of trabecular surface, this finding suggests a decrease in (re)modeling activity during development. In accordance with the general growth and development of the pig, it was concluded that most developmental changes in cancellous bone occur until the age of 40 weeks postpartum.     

Unchanged glutamine synthetase activity and increased NMDA receptor density in epileptic human neocortex: implications for the pathophysiology of epilepsy

We investigated whether alterations in glutamate metabolising glutamine synthetase activity occur in human epileptic neocortex, as shown previously for human epileptic hippocampus [Eid, T., Thomas, M.J., Spencer, D.D., Rundén-Pran, E., Lai, J.C.K., Malthankar, G.V., Kim, J.H., Danbolt, N.C., Ottersen, O.P., de Lanerolle, N.C., 2004. Loss of glutamine synthetase in the human epileptic hippocampus: possible mechanism for raised extracellular glutamate in mesial temporal lobe epilepsy. Lancet 363, 28-37]. Glutamine synthetase activity was equivalent in both non-epileptic and epileptic human neocortex. Epileptic tissue, however, was characterised by a 37% increase in the density of synaptosomal NMDA receptor sites compared to non-epileptic tissue, as revealed by a radioligand binding assay (B max(non-epileptic) 1.45 pmol/mg protein and B max(epileptic) 1.99 pmol/mg protein, P < 0.05). Our findings shed some doubts on a role of glutamine synthetase in the pathophysiology of epilepsy in the neocortex. However, the detection of a significantly reduced enzymatic activity in the epileptic amygdala supports the assumption that the enzyme defect is localized to the epileptic mesial temporal lobe of corresponding patients.     

Assessing Musical Abilities Objectively: Construction and Validation of the Profile of Music Perception Skills

A common approach for determining musical competence is to rely on information about individuals’ extent of musical training, but relying on musicianship status fails to identify musically untrained individuals with musical skill, as well as those who, despite extensive musical training, may not be as skilled. To counteract this limitation, we developed a new test battery (Profile of Music Perception Skills; PROMS) that measures perceptual musical skills across multiple domains: tonal (melody, pitch), qualitative (timbre, tuning), temporal (rhythm, rhythm-to-melody, accent, tempo), and dynamic (loudness). The PROMS has satisfactory psychometric properties for the composite score (internal consistency and test-retest r>.85) and fair to good coefficients for the individual subtests (.56 to.85). Convergent validity was established with the relevant dimensions of Gordon’s Advanced Measures of Music Audiation and Musical Aptitude Profile (melody, rhythm, tempo), the Musical Ear Test (rhythm), and sample instrumental sounds (timbre). Criterion validity was evidenced by consistently sizeable and significant relationships between test performance and external musical proficiency indicators in all three studies (.38 to.62, p<.05 to p<.01). An absence of correlations between test scores and a nonmusical auditory discrimination task supports the battery’s discriminant validity (−.05, ns). The interrelationships among the various subtests could be accounted for by two higher order factors, sequential and sensory music processing. A brief version of the full PROMS is introduced as a time-efficient approximation of the full version of the battery.     

不同胁迫预处理提高水稻幼苗抗寒性期间蛋白质的变化

水稻(Oryza sativa L.)幼苗经盐、热激和冷三种不同胁迫预处理均提高了幼苗的抗寒性。与未预处理苗相比,在处理后、低温伤害后和常温下恢复2d的三个时期,不同胁迫预处理苗的可溶性和热不稳定蛋白含量变化趋势甚为相似,但热稳定蛋白含量变化则各有异同。SDS-PAGE图谱分析显示,不同胁迫预处理提高水稻幼苗抗寒性时,其可溶性蛋白、热稳定和热不稳定蛋白组成变化亦各有异同。除诱导出共有的新多肽外,还各自诱导出特有的新多肽。结果表明,植物对不同胁迫的交叉适应存在一定的共同机理,但亦可看出植物对同一种环境胁迫似乎不是以同一的机理去适应。     

Purification and characterization of Dolichos lablab lectin

The mannose/glucose-binding Dolichos lablab lectin (designated DLL) has been purified from seeds of Dolichos lablab (hyacinth bean) to electrophoretic homogeneity by affinity chromatography on an ovalbumin- Sepharose 4B column. The purified lectin gave a single symmetric protein peak with an apparent molecular mass of 67 kDa on gel filtration chromatography, and five bands ranging from 10 kDa to 22 kDa upon SDS-PAGE. N-Terminal sequence analysis of these bands revealed subunit heterogeneity due to posttranslational proteolytic truncation at different sites mostly at the carboxyl terminus. The carbohydrate binding properties of the purified lectin were investigated by three different approaches: hemagglutination inhibition assay, quantitative precipitation inhibition assay, and ELISA. On the basis of these studies, it is concluded that the Dolichos lablab lectin has neither an extended carbohydrate combining site, nor a hydrophobic binding site adjacent to it. The carbohydrate combining site of DLL appears to most effectively accommodate a nonreducing terminal alpha-d-mannosyl unit, and to be complementary to the C-3, C-4, and C-6 equatorial hydroxyl groups of alpha-d-mannopyranosyl and alpha-d-glucopyranosyl residues. DLL strongly precipitates murine IgM but not IgG, and the recent finding that this lectin interacts specifically with NIH 3T3 fibroblasts transfected with the Flt3 tyrosine kinase receptor and preserves human cord blood stem cells and progenitors in a quiescent state for prolonged periods in culture, make this lectin a valuable tool in biomedical research.      

Effect of dietary selenium concentration and duration of selenium feeding on hepatic glutathione concentrations in rats

Studies were conducted in rats to determine the effect of dietary selenium (Se) concentration on hepatic glutathione concentrations and enzyme activities associated with the maintenance of the cellular glutathione status. Male rats were fed 0.1, 3.0, or 6.0 ppm Se as Na2SeO3 for 2, 4, or 6 weeks at which time they were killed and analyses were performed. Both 3.0 and 6.0 ppm Se caused a significant dose-dependent increase in hepatic-reduced glutathione (GSH) by 4 weeks of feeding compared to 0.1 ppm Se. The increase in GSH was preceded by significant, dose-dependent increases in oxidized glutathione (GSSG) as well as the GSSG to GSH ratio. Increases in GSSG and the GSSG to GSH ratio as well as in glutathione reductase and glucose-6-phosphate dehydrogenase activities were observed by 2 weeks of high Se feeding. The current findings substantiate previous results demonstrating effects of high Se on hepatic glutathione concentrations (R. A. LeBoeuf and W. G. Hoekstra, J. Nutr. 113:845-854, 1983) and further suggest that increased cellular GSSG concentrations or the GSSG to GSH ratio caused by 3.0 and 6.0 ppm dietary Se signals for "adaptive" changes in hepatic glutathione metabolism.