全国大学生生命科学竞赛数据分析与展望

全国大学生生命科学竞赛至今已举办三届,赛事组织好、规模大、参与度高,对促进生命科学教育与研究具有重要作用。文中简述全国大学生生命科学竞赛的模式与现状,并基于前三届竞赛数据分地区分年度统计分析报名数据和竞赛成绩,同时结合生命科学领域的新变化新认识进行展望,以更好地推动赛事发展。     

Ageing Effect Evaluation on HD-sEMG Signals Using CCA Approach

ObjectivesThe objective of the proposed study is to exploit the technology of high-density surface electromyography (HD-sEMG), in order to evaluate the muscle activation in young and elderly subjects during a daily life gesture, namely, Sit To Stand (STS), using wireless connected ambulatory equipment (TMSi©) and Blind Source Separation (BSS) approach with Canonical Correlation Analysis (CCA).Materials and methodsSixteen subjects participated (50% females) divided into two categories (‘H1’: young (30.62 yrs ±5.92, 23.95 kg/m² ±3.08), versus ‘H2’: old (61.87 yrs ±7.98, 23.4 kg/m² ±3.38)), in the recording of HD-sEMG signals, using 32-electrodes square grids (4×8), during Sit To Stand (STS) motion, three times at spontaneous speed. The studied muscle is the Rectus Femoris (RF) muscle. The recorded HD-sEMG signals were analyzed with CCA approach to extract correlation coefficient sets according to two age categories (young versus old), in order to evaluate its discriminating power with ageing. Statistical tests (t-test) were used to evaluate the discrimination for these two categories.ResultsThe calculation of CCA correlation coefficients showed a significant difference between young and old category concerning the mean CCA correlation coefficient (P<0.001***) and also the standard deviation of the CCA correlation coefficients (P<0.0001****).ConclusionThe obtained results are promising and indicate a clear difference between the obtained source variability using CCA method between the young and the old tested subjects during daily life motion. Furthermore, these estimated sources seem to be impacted by both anatomical and functional modifications with ageing.     

News from the BSC No. 8

Abstract

In the 8th and following issues of News from the Biological Stain Commission (BSC), under the heading of Regulatory affairs, the BSC's International Affairs Committee will present information from a meeting held in Ghent, Belgium on 15–18 June 2009 concerning the progress achieved by the International Standards Organization Committee ISO/TC 212 Clinical Laboratory Testing and in Vitro Diagnostic Test Systems since the last meeting held in Vancouver, Canada in 2008. A note on the meaning and significance of E numbers found on the labels of foodstuffs and beverages sold for human consumption concludes this edition of News from the Biological Stain Commission.     

Is the edTPA the Right Choice for Evaluating Teacher Readiness?

The purpose of this article is to describe and analyze the edTPA, a performance assessment created by the Stanford Center for Assessment, Learning, and Equity (SCALE) and administered by Pearson, Inc., to assess the professional readiness of student teachers. We challenge claims made in support of using this assessment, specifically within the context of arts teacher preparation programs, and we address areas of immediate critical concern to make alternative recommendations.     

Free radicals act as effectors in the growth inhibition and apoptosis of iron-treated Burkitt's lymphoma cells

The addition of ferric citrate to Burkitt's lymphoma (BL) cell lines inhibits growth, leads to the accumulation of cells in the phase G₂/M of the cell cycle and to the modulation of translocated c-myc expression. The increase in the labile iron pool (LIP) of iron-treated BL cells leads to cytotoxicity. Indeed, intracellular free iron catalyzes the formation of highly reactive compounds such as hydroxyl radicals and nitric oxide (NO) that damages macromolecular components of cells, eventually resulting in apoptosis. In this report, we have investigated the possible involvement of free radicals in the response of Ramos cells to iron. When added to Ramos cells, iron increased the intracellular levels of peroxide/peroxynitrite and NO. Moreover, the addition of free radicals scavengers (TROLOX^® and Carboxy-PTIO) neutralized the effects of iron on Ramos cells while addition of an NO donor or hydrogen peroxide (H₂O₂) to cells generated effects which partially mimicked those induced by iron addition. Collectively, our results suggest the involvement of free radicals as effectors in the iron specific growth inhibition of BL cells observed in vitro.     

PON1 Paraoxonase Activity is Reduced During HDL Oxidation and is an Indicator of HDL Antioxidant Capacity

The aim of this study was to investigate the effect of HDL oxidation on PON1 paraoxonase activity. Also, we were interested in investigating the mechanism by which PON1 could be inactivated and the correlation between its enzymatic activity and the antioxidant properties of HDL. Three different oxidation systems were used for the HDL oxidation: (1) oxidation induced by THP1 cells, (2) oxidation induced by copper ions at a concentration 10 &#119 M, and (3) oxidation induced by &#148 OH and O 2 &#148 &#109 oxygen free radicals produced by &#110 -radiolysis. HDL oxidation was followed by the measurement of lipid peroxide formation, and PON1 activity was determined by measuring the rate of paraoxon hydrolysis. Our results show that HDL oxidation is accompanied by a reduction in the PON1 paraoxonase activity. The extent of PON1 inactivation depends both on the extent of HDL oxidation and on the oxidation system used. The rates of HDL oxidation and PON1 inactivation were significantly correlated ( r =0.93, p <0.0054). Our results show that oxidized HDL loses its protective effect toward LDL oxidation. The antioxidant action of HDL towards LDL oxidation and the degradation of PON1 paraoxonase activity were significantly correlated ( r =0.95, p <0.04).     

Mitochondrial oxidative stress elicits chromosomal instability after exposure to isocyanates in human kidney epithelial cells

The role of oxidative stress is often attributed in environmental renal diseases. Isocyanates, a ubiquitous chemical group with diverse industrial applications, are known to undergo bio-transformation reactions upon accidental and occupational exposure. This study delineates the role of isocyanate-mediated mitochondrial oxidative stress in eliciting chromosomal instability in cultured human kidney epithelial cells. Cells treated with 0.005 µM concentration of methyl isocyanate displayed morphological transformation and stress-induced senescence. Along the time course, an increase in DCF fluorescence indicative of oxidative stress, depletion of superoxide dismutase (SOD) and glutathione reductase (GR) and consistent accumulation of 8-oxo-dG were noticed. Thus, endogenous oxidative stress resulted in aberrant expression of p53, p21, cyclin E and CDK2 proteins, suggestive of deregulated cell cycle, chromosomal aberrations, centromeric amplification, aneuploidy and genomic instability.     

Free Radicals and Lipid Peroxidation in Liver of Rats Kept on a Diet Devoid of Choline

Rodents kept on a choline devoid (CD) diet up to 14 months develop hepatic lesions progressing through two broad stages. The first is chracterized by severe steatosis and increase in cell turnover, the second by a gradual clearance of the deposited fat and fibrosis. Hepatocellular carcinomas eventually arise in rats fed for over 12 months, even though the animals aer not exposed to chemical carcinogens. It has been suggested that the diet may trigger generated thereby may be responsible for intiation of liver cancer and promotion. The radicals would lead to DNA damage, and the altered DNA in a proliferating liver would result in initiation of the carcinogenic process. In this communication we present evidence that the diet used in the above studies contained stable fatty acid isomers with conjugated dienes, which are absorbed and deposited in rat liver. This finding cast doubts on whether a CD diet does indeed cause a peroxidation of cellular membrane lipids. Electron spin resonance (ESR) spectroscopy was also used to investigate whether any abnormal pattern of free radicals exists in the liver of rats fed a CD diet. No significant differences were noted in ESR spectra of either transition metal-centered signals, or organic free radicals.