Evidence for peroxynitrite-mediated modifications to p53 in human gliomas: possible functional consequences

Based on previous findings of increased nitric oxide synthase (NOS) expression in human gliomas (4), we hypothesized that peroxynitrite, a highly reactive metabolite of nitric oxide (NO) and superoxide (O(*-)(2)), might be increased in these tumors in vivo. Here we demonstrate that nitrotyrosine (a footprint of peroxynitrite protein modification) is present in human malignant gliomas. Furthermore, we show that p53, a key tumor suppressor protein, has evidence of peroxynitrite-mediated modifications in gliomas in vivo. Experiments in vitro demonstrate that peroxynitrite treatment of recombinant wild-type p53 at physiological concentrations results in formation of higher molecular weight aggregates, tyrosine nitration, and loss of specific DNA binding. Peroxynitrite treatment of human glioma cell lysates similarly resulted in selective tyrosine nitration of p53 and was also associated with loss of p53 DNA binding ability. These data indicate that tyrosine nitration of proteins occurs in human gliomas in vivo, that p53 may be a target of peroxynitrite in these tumors, and that physiological concentrations of peroxynitrite can result in a loss of p53 DNA binding ability in vitro. These findings raise the possibility that peroxynitrite may contribute to loss of wild-type p53 functional activity in gliomas by posttranslational protein modifications.     

Stepwise Kinetic Equilibrium Models of Quantitative Polymerase Chain Reaction

ABSTRACT: BACKGROUND: Numerous models for use in interpreting quantitative PCR (qPCR) data are present in recent literature. The most commonly used models assume the amplification in qPCR is exponential and fit an exponential model with a constant rate of increase to a select part of the curve. Kinetic theory may be used to model the annealing phase and does not assume constant efficiency of amplification. Mechanistic models describing the annealing phase with kinetic theory offer the most potential for accurate interpretation of qPCR data. Even so, they have not been thoroughly investigated and are rarely used for interpretation of qPCR data. New results for kinetic modeling of qPCR are presented. RESULTS: Two models are presented in which the efficiency of amplification is based on equilibrium solutions for the annealing phase of the qPCR process. Model 1 assumes annealing of complementary targets strands and annealing of target and primers are both reversible reactions and reach a dynamic equilibrium. Model 2 assumes all annealing reactions are nonreversible and equilibrium is static. Both models include the effect of primer concentration during the annealing phase. Analytic formulae are given for the equilibrium values of all single and double stranded molecules at the end of the annealing step. The equilibrium values are then used in a stepwise method to describe the whole qPCR process. Rate constants of kinetic models are the same for solutions that are identical except for possibly having different initial target concentrations. Analysis of qPCR curves from such solutions are thus analyzed by simultaneous non-linear curve fitting with the same rate constant values applying to all curves and each curve having a unique value for initial target concentration. The models were fit to two data sets for which the true initial target concentrations are known. Both models give better fit to observed qPCR data than other kinetic models present in the literature. They also give better estimates of initial target concentration. Model 1 was found to be slightly more robust than model 2 giving better estimates of initial target concentration when estimation of parameters was done for qPCR curves with very different initial target concentration. Both models may be used to estimate the initial absolute concentration of target sequence when a standard curve is not available. CONCLUSIONS: It is argued that the kinetic approach to modeling and interpreting quantitative PCR data has the potential to give more precise estimates of the true initial target concentrations than other methods currently used for analysis of qPCR data. The two models presented here give a unified model of the qPCR process in that they explain the shape of the qPCR curve for a wide variety of initial target concentrations.     

儿童过敏性紫癜早期肾损伤中VCAM-1的临床意义

目的：探讨血管细胞粘附分子-1（VCAM-1）的检测在儿童过敏性紫癜（AP）早期肾损伤中的临床意义。方法：选择明确诊断为AP 患儿85 例,均为早期无肾损害的AP病儿。根据第七版诸福棠实用儿科学有关章节的诊断标准和随访结果,进一步将研究对象分为有肾损害AP 为APN 组,无肾损害AP为AP 组,于同时间、同群体中选择健康儿童35 名为对照组。应用ELISA 法分别检测三组患儿早期无肾损害时血VCAM-1 的含量,分析血VCAM-1在儿童过敏性紫癜早期肾损伤中的临床意义。结果：APN 组血VCAM-1 水平均高于AP组和正常对照组;AP 组亦高于正常对照组,差异均有统计学意义（P〈0.01）。结论：对早期无肾损害的AP病儿,检测血浆VCAM-1 对AP发生APN 的预后诊断有重要的临床意义。     

血清胆红素水平与缺血性卒中的相关性研究

目的：脑卒中是威胁人类健康三大疾病之一,是我国成人致残的首要原因,其中80％是缺血性卒中。本文意在研究血清胆红素水平与缺血性卒中严重程度、发病机理以及颈动脉粥样硬化斑块的关系,以进一步为防治缺血性卒中的发生、发展提供新的途径。方法：选择缺血性脑卒中患者（观察组）150例和同期健康体检者（对照组）150例,分别测定两组的血清总胆红素水平（TBIL）、间接胆红素（DBIL）、直接胆红素（IBIL）,并对病例组进行TOAST分型、NIHSS评分及颈部血管超声检查。比较两组间血清胆红素,及观察组内不同分型组间血清胆红素的差异。结果：缺血性卒中患者TBIL、DBIL水平显著高于正常对照组,差异具有统计学意义（P〈0．05）。缺血性卒中患者按TOAST分型各亚型间血清TBIL、DBIL、IBIL水平差异无统计学意义（P〉0．05）。中重型脑梗死组与轻型脑梗死组比较,血清TBIL、DBIL、IBIL浓度均明显升高,差别具有统计学意义（P〈0．05）。缺血性卒中患者中有动脉粥样硬化斑块形成组血清TBIL、DBIL水平低于颈部动脉内膜光滑、完整者组,差别有统计学意义（P〉0．05）。结论：缺血性卒中患者血清胆红素升高,参与急性应激反应,可能作为衡量缺血性卒中严重程度的指标之一;高水平血清胆红素可能预防颈动脉粥样硬化斑块的形成,从而预防缺血性卒中的发生。     

Origin of X/O progeny from crosses of sex-ratio trait males of Drosophila pseudoobscura

Males of Drosophila pseudoobscura carrying the sex-ratio chromosome (SR) were studied to determine the cause of X/O male progeny that they produce. It was found that among 3671 X/O progeny virtually all resulted from nullo-X sperm. The experiment also revealed a dramatic clustering of the frequency of X/O progeny among SR/Y males. This is interpreted to indicate that premeiotic events in the male germ line are the cause of nullo-X sperm.     

Prevalence of keds on city dogs in central Poland

The aim of this study was to identify the species of ked infesting dogs in the cities of central Poland. A total of 510 dogs were observed between June and September 2015. The presence of keds was noted in 182 (35.7%) animals. Keds were more prevalent in female (38.0%) than in male (33.2%) dogs, and were more frequently found in animals younger than 1 year (46.2%) and in long‐haired dogs (36.6%). The body areas most heavily colonized by keds were the groin (35.4%) and neck (21.4%). A total of 904 keds were isolated from dogs, including Hippobosca equina (Diptera: Hippoboscidae) (17.2%), Lipoptena cervi (Diptera: Hippoboscidae) (32.0%), and two species not previously encountered in Poland: Hippobosca longipennis (45.0%) and Lipoptena fortisetosa (5.9%). Hippoboscidae may act as vectors of pathogens and any shifts in their geographic range may lead to the spread of new diseases affecting animals.     

Spermatogenesis in the archaic hydrothermal vent bivalve,Bathypecten vulcani,and comparison of spermatozoon ultrastructure with littoral pectinids

Summary

Bathypecten vulcani is considered a relict species from the Paleozoic, based on shell characteristics such as the presence of calcite prisms. To date, it is the only pectinid species reported from hydrothermal ecosystems. Histological and ultrastructural studies show that spermatogenesis is identical to that of littoral pectinids. The spermatozoon has a 2.7 μm long pyriform head and a 40 μm flagellum. The four mitochondria of the mid-piece are about 1.2 μm in diameter. The nucleus contains dense chromatin fibres and possesses a wide, shallow (0.1 μm) anterior fossa and a narrow, deeper (0.2 μm) posterior nuclear fossa. Comparison of the ultrastructural characteristics of the spermatozoon of B. vulcani with those of littoral pectinids shows that they can be used as a diagnostic feature of this species. In particular, its acrosome characters will be a useful complement to the shell characters in the study of the phylogenetic position of this species in relation to other pectinids.