ATP-dependent Ca2+-transporting system in the rat brain during an early period of acute radiation injury

The rate of Mg2+, Ca2+-ATPase reaction and ATP-dependent Ca2+ accumulation in a preparation of plasma membranes from brain synaptosomes increases 60 min following whole-body X-irradiation of rats with a dose of 0.21 C/kg, a calcium sensitivity of both processes being increased. A unidirectional change in their kinetics indicates the early radiosensitivity of Ca2+ transfer systems in the brain synaptosome membranes. There is an increase in the availability of SH-groups of membrane preparation proteins for SH-reagents and in the sensitivity of Mg2+, Ca2+-ATPase reaction and ATP-dependent Ca2+ accumulation to trifluoperazine, a calmodulin inhibitor. Both processes lose their ability to be activated by exogenous calmodulin. It is suggested that at an early stage of radiation affection, a change occurs in the molecular organization of the ATPase-calmodulin membrane complex in plasma membranes of rat brain synaptosomes.     

Morphological restructuring of the cellular elements of the ventral tegmental area in selective damage to the catecholaminergic systems of the brain

Electron microscopical investigation of the ventral tegmental area at various time after administration of a specific neurotoxin 6-hydroxydopamine made it possible not only to reveal catecholamine reactive elements, but also those structural reorganizations in them, that are dependent on the lesion of the catecholaminergic systems, including certain changes in the receptor apparatus. Dark neurons with the change of different organelles preserve for a long time, up to 2.5 months. Reactive and destructive reorganizations of some axons, terminal buttons and postsynaptic poles of the ventral tegmental area are accompanied with certain functional disturbances, observed both experimentally and at a pathological process. The results of the work demonstrate that under conditions of the model experiments there is a possibility to study various stages of pathogenesis of a number of nervous-psychical diseases, connected or accompanied with disorders in certain mediator systems.     

Structural changes in the sarcoplasmic reticulum membrane of skeletal muscles at the early stage of x-ray irradiation]

A single X-ray irradiation of the rabbit hindlimbs in a dose of 0.24 C/kg evokes a decrease in fluorescence of the ANS probe bound with membranes of the sarcoplasmatic reticulum as a result of the decrease of binding sites, binding constant as well as the quantum output of the probe. A decrease in fluorescence of tryptophan residues of Ca-ATPase localized in membranes and attenuation of interaction of its SH-group with dithionitrobenzoic acid has been also observed at early postradiation terms (1 and 24 h). The obtained results evidence for structural rearrangements occurring in membranes of the sarcoplasmic reticulum under the effect of ionizing radiation. Changes in conformation of CA-ATPase molecules contribute much to this process.     

Phospholipase A2 from rat spleen lymphocytes hydrolyzing arachidonoyl-phospholipids]

Phospholipase A2 activity in the postnuclear supernatant of lymphocytes has been studied by measuring 14C arachidonate released from labelled phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC) as exogenous substrates. The pH optimum was 7.5-9.0 for PE and 9.0 for PC. Phospholipase A2 was not detected in the presence of 2 mM EGTA. It was optimal with the millimolar calcium concentrations and higher towards PE. Preincubation of lymphocytes with 0.5 M ionophore A-23187 was followed by 2.4 fold stimulation of the phospholipase activity. A stimulatory effect was observed after preincubation of cells with 10 micrograms/ml of phytohemagglutinin, lipopolysaccharide, concanavalin A; it decreased as: lipopolysaccharide greater than phytohemagglutinin greater than concanavalin A. The results obtained have suggested the possibility of existence of different forms of phospholipase A2 in the spleen lymphocytes and participation of the enzyme in the early signalling events.     

Study of the kinetics of thermoinactivation of lysyl-tRNA-synthetase from the liver of x-irradiated rats

A study was made of the kinetics of thermoinactivation of lysyl-tRNA-synthetase isolated from rat liver at early times of radiation damage development after the effect of a minimum absolutely lethal X-radiation dose (0.21 C/kg). The thermostability of a dimer form of the enzyme was shown to be higher than that of a monomer. It was established that substrates had a stabilizing effect on the enzyme during thermoinactivation. On the basis of the data obtained from the studies in the kinetic properties of the enzyme and the thermoinactivation a conclusion is made that lysyl-tRNA-synthetase is stabilized during subunit aggregation. The thermostability of the enzyme was decreased by irradiation.     

Effect of gaseous hypoxic mixture GHM-10 on the intestinal death of Wistar rats and Na+,K+-ATPase activity of the plasma membrane of the small intestine mucosa after irradiation

It was shown that gas hypoxic mixture containing O2 (10%) and N2 (90%) significantly decreases "intestinal" death of Wistar rats on the 5th day following irradiation and normalizes Na+,K+-ATPase activity of the small intestine mucosa plasma membranes.     

定量分析调控人类免疫缺陷病毒潜伏与激活的动力学机制

目的 治疗艾滋病最大的障碍在于无法根除人类免疫缺陷病毒（HIV）潜伏于人体细胞所形成的病毒存储库。构建描述病毒存储库建立分子机制的动力学模型需考虑生物体内的噪声环境和多重影响因素,本文通过一种全新的动力学结构分解方法将随机微分方程的确定性部分与随机性噪声分开,从而在仅需分析常微分方程不动点的情况下即可判断不同药物靶点的作用效果。方法 使用连续的随机微分方程构建了HIV转录过程的动力学模型,简化了描述系统所需方程的维度,增大了模型的可探索空间,在此基础上,通过计算得到的势能函数和概率分布函数直观表示病毒潜伏与激活的不同表达状态以及它们之间的关系。结果 定量分析了不同动力学参数对系统稳态和势函数的影响程度,分别得到了系统处于双稳态和单稳态时的参数范围,并将不同因素对动力系统分岔的影响程度与生物学实验结果对比,验证了本工作的理论基础。结论 本文突破了以往离散、随机的方法,可以通过常微分方程定量分析HIV转录调控的动力学机制,有利于推广到处理高维情况,进一步研究艾滋病在生物体内的发生发展,从而指导设计实验寻找临床上的治疗方案。     

The content of phospholipids and free fatty acids in the sarcoplasmic reticulum membranes in the early stage of an x-ray radiation lesion

One and 24 h following single X-irradiation (0.21 C/kg) of rabbit hind leg the content of free fatty acids and phospholipid lysoforms increased in the sarcoplasmic reticulum (SR) membrane of skeletal muscles. The results obtained are important in estimating the mechanisms of action of ionizing radiation on the structural and functional properties of SR.     

受体相互作用蛋白质激酶3通过上调整合素β3促进骨关节炎相关病变

骨关节炎（osteoarthritis,OA）是最常见的慢性致残性关节疾患,目前尚无针对病因的有效治疗手段。程序性坏死在多种疾病中扮演关键角色,受体相互作用蛋白质激酶3（receptor-interacting protein kinase 3, RIP3）是程序性坏死进程的关键调控因子。有研究显示,RIP3在人与鼠骨关节炎退变软骨组织中表达水平显著上调,提示程序性坏死的发生,但RIP3在软骨中的具体病生理角色仍不明确。本研究拟对过表达RIP3前后的软骨细胞转录物组进行测序分析,探索RIP3在骨关节炎进程中发挥作用的具体机制。RNA测序结果显示,RIP3的过表达诱发软骨细胞中244个基因表达上调,277个表达下调。通过进一步构建基因间共表达作用网络,筛选出16个候选靶基因在mRNA水平进行验证,证实RIP3对磷脂酰肌醇3激酶调节亚单位5（phosphoinositide-3-kinase, regulatory subunit 5,Pik3r5）、整合素β3（integrin subunit beta 3,Itgb3）及成髓细胞瘤转录因子第2亚型（MYB proto-oncogene like 2,Mybl2）的表达上调作用最为显著。CCK-8以及乳酸脱氢酶活性检测结果表明,利用siRNA沉默Itgb3的表达可显著抑制RIP3诱发的软骨细胞活力下降及程序性坏死,同时也抑制了RIP3对软骨细胞中分解代谢相关基因Mmp1、Mmp13与Il6的表达上调作用,以及其对合成代谢相关基因Acan、Col2a1与Sox9的下调作用。本研究证实,RIP3通过上调软骨细胞中Itgb3的表达诱发软骨细胞坏死与软骨基质代谢紊乱,并最终导致软骨退变,为骨关节炎的临床治疗提供了新靶点,同时进一步明确了程序性坏死的病理生理学意义。