The p53 Codon 72 PRO/PRO Genotype May Be Associated with Initial Central Visual Field Defects in Caucasians with Primary Open Angle Glaucoma

Background

Loss of vision in glaucoma is due to apoptotic retinal ganglion cell loss. While p53 modulates apoptosis, gene association studies between p53 variants and glaucoma have been inconsistent. In this study we evaluate the association between a p53 variant functionally known to influence apoptosis (codon 72 Pro/Arg) and the subset of primary open angle glaucoma (POAG) patients with early loss of central visual field.

Methods

Genotypes for the p53 codon 72 polymorphism (Pro/Arg) were obtained for 264 POAG patients and 400 controls from the U.S. and in replication studies for 308 POAG patients and 178 controls from Australia (GIST). The glaucoma patients were divided into two groups according to location of initial visual field defect (either paracentral or peripheral). All cases and controls were Caucasian with European ancestry.

Results

The p53-PRO/PRO genotype was more frequent in the U.S. POAG patients with early visual field defects in the paracentral regions compared with those in the peripheral regions or control group (p = 2.7×10⁻⁵). We replicated this finding in the GIST cohort (p  = 7.3×10⁻³, and in the pooled sample (p = 6.6×10⁻⁷) and in a meta-analysis of both the US and GIST datasets (1.3×10⁻⁶, OR 2.17 (1.58–2.98 for the PRO allele).

Conclusions

These results suggest that the p53 codon 72 PRO/PRO genotype is potentially associated with early paracentral visual field defects in primary open-angle glaucoma patients.     

A Unidirectional Cell Switching Gate by Engineering Grating Length and Bending Angle

On a microgrooved substrate, cells migrate along the pattern, and at random positions, reverse their directions. Here, we demonstrate that these reversals can be controlled by introducing discontinuities to the pattern. On “V-shaped grating patterns”, mouse osteogenic progenitor MC3T3-E1 cells reversed predominately at the bends and the ends. The patterns were engineered in a way that the combined effects of angle- and length-dependence could be examined in addition to their individual effects. Results show that when the bend was placed closer to one end, migration behaviour of cells depends on their direction of approach. At an obtuse bend (135°), more cells reversed when approaching from the long segment than from the short segment. But at an acute bend (45°), this relationship was reversed. Based on this anisotropic behaviour, the designed patterns effectively allowed cells to move in one direction but blocked migrations in the opposing direction. This study demonstrates that by the strategic placement of bends and ends on grating patterns, we can engineer effective unidirectional switching gates that can control the movement of adherent cells. The knowledge developed in this study could be utilised in future cell sorting or filtering platforms without the need for chemotaxis or microfluidic control.     

三江平原湿地——虎林地区夏季浮游植物群落结构特征

对三江平原湿地虎林地区水域的浮游植物群落结构进行了初步研究。在采集区域设置10个采样点,经鉴定共有133个浮游植物分类单位,隶属于8门10纲16目27科48属。该地区浮游植物群落组成以硅藻门(Bacillariophyta)、绿藻门(Chlorophyta)为主。各采样点浮游植物种类组成及细胞密度差异显著,采样点Ⅸ的浮游植物种类最丰富,采样点Ⅱ的浮游植物细胞密度最大。在三江平原湿地虎林地区发现了大量的β-中污指示种,经聚类和多维尺度分析评价,初步推断三江平原湿地虎林地区水域受到一定污染,呈中营养状态。     

Comparison of adipose glycerol kinase of hyperglycemic obese mice and lean litter-mates

Summary Glycerol kinase activity found in the epididymal adipose tissue of lean litter-mates of hyperglycemic obese mice exhibits two distinct Km values. The Km(s) obtained graphically by a Hoftsee plot are 40 and 637 m. The glycerol kinase of obese mice showed 29 times more total activity per fat pad or 9 times more activity per mg of protein as compared to that of the lean controls. The increased glycerol kinase activity found in the obese mice predominantly exhibited low Km value. Increase in the activity with the high Km value was minimal. The apparent molecular weight of adipose glycerol kinase is approximately 60,000–65,000. A higher activity of glycerol kinase in the epididymal adipose tissue of the obese mice (ob/ob) has been reported by Treble and Mayer ¹. The significance of this increased enzyme in obesity² has been investigated by many investigators^3–6, using either whole epididymal fat pad or isolated fat cells as the source of glycerol kinase. However, little is known regarding the properties of this enzyme, and even the characterization of the liver glycerol kinase is not yet complete^{7, 8}.We have recently shown that adipose glycerol kinase of Sprague-Dawly rat and of Swiss mice exhibit two Km values, and the apparent molecular weight is approximately 55,000–60,000⁹. The present study was undertaken in order to establish whether the enzyme in ob/+ mice also exhibits two Km values and if so, whether the activity associated with both Km(s) is increased. We found that the specific conditions for enzyme activity determination and the basis on which the activity is expressed are quantitatively important in clarifying the difference in glycerol kinase activity of ob/ob and ob/+ mice. The increased activity in ob/ob mice is predominantly the low Km enzyme, and the apparent molecular weight is approximately 60,000–65,000.Supported in part by the Juvenile Diabetes Foundation. We thank Mr. CHARLES ROSENTHAL for technical assistance.     

植物性雌激素genistein对豚鼠乳头肌的电生理效应

应用细胞内微电极技术,观察了genistein(GST)对豚鼠乳头肌的电生理效应。结果显示：（1）GST（10-100μmol/L)浓度依赖地缩短正常乳头肌动作电位时程;（2）对部分去极化乳头肌,GST（50μmol/L)除缩短动作电位时程外,还使动作电位幅值和超射值降低,零相最大上升速度减慢;（3）预先应用一氧化氮合酶抑制剂L-NNA（5mmol/L)。不影响GST（50μmol/L)的电生理效应;（4）单独应用17β-雌二醇（E2,5μmol/L)或GST（10μmol/L)时,动作电位各参数无明显变化。而预先应用同剂量的GST再加入E2,则动作电位时程缩短,结果提示,GST可能通过非NO途径抑制Ca^2 内流,从而影响豚鼠乳头肌电生理效应,并与E2有加强或协同效应。     

中国典型草原放牧草场蝗虫为害损失及经济阈值的估算(英语)

传统上估算蝗虫在放牧草场为害损失的方法几乎都是用来测定对牧草秋季产量的影响,而实际上,在估算放牧草场蝗虫为害损失及经济阈值时,牧草的现存量而非秋季产量是更应考虑的因素.本文提出了一种适合测定蝗虫对牧草现存生物量影响的新方法,即野外挂笼饲养与蝗虫种群动态相结合的估算方法,并在此基础上组建了放牧草场蝗虫种群经济阈值模型;α_0 α_1M_1_α_2M_2_ α_3S_1 α_4S_2=C其中,M_1:狭翅雏蝗生物量;M_2:宽须蚁蝗生物量;S_1:狭翅雏蝗平均个体重量,S_2:宽须蚁蝗平均个体重量;α_0-α_4:常数.同时引入蝗虫种群数量和生物量两项参数来表达蝗虫种群的发生程度.