Actiprotective and antihypoxic action of new heteroaromatic antioxidants

Expernents with mice showed that most of 15 new heteroaromatic antioxidant compounds possess aciprotective and antixopixic properties. Based on results of treadmill and swimming tests, actiprotective action of IBKhF-1, 11 and 14 surpassed greatly bemythil and bromanthane in ordinary conditions. Inhibitor of gluconeogenase tryptophan cancelled largely the stimulatting action of highly effective and active IBKhF-1, 2 and 11 on physical performance during treadmill exercise. Consequently, gluconeogenesis activation is one of the major components of the actiprotective action of these antioxidants. In addition, IBKhF-1, 11 and 14 excelled bemythil and bromanthane in the extreme conditions of running in hyperthermia and swimming in acute hypoxia combined with hypercapnia. IBKhF-2 and 14 were better than amtisol (standard antihypoxic agent) and bemythil against acute hypoxia in pressure chamber, whereas IBKhF-4 and 14 excelled these agents in thermal chamber.     

Synthesis of carbon dots from taurine as bioimaging agent and nanohybrid with ceria for antioxidant and antibacterial applications

Here we have synthesized water soluble and biocompatible carbon dots (CDs) from taurine via thermal decomposition method. The CDs showed nearly spherical shape with diameter less than 10 nm. The CDs exhibited excitation dependent fluorescence emission and could be used for mammalian cell imaging. The CDs showed excellent DPPH and hydrogen peroxide radical scavenging activity in cell free system. Besides, the CDs also displayed significant intracellular radical scavenging activity in human normal kidney epithelial (NKE) cells. Furthermore, nanohybrids consisting of both CDs and nanoceria (CeO₂) were prepared and tested for their biomedical applications. The nanohybrids showed significant antioxidant activities in both cell free and intracellular conditions. The CDs and nanohybrids possessed very little toxicity upto the concentration of 100 μg/mL when treated for 24 hours in human NKE cells. The CDs as well as nanohybrids further displayed significant bacterial growth inhibition against both gram-positive and gram-negative bacteria under dark as well as light illumination condition via the bacterial membrane damage. However, under the light illumination, the bacterial growth inhibition of CDs and nanohybrids was further enhanced due to the generation of reactive oxygen radicals and subsequent DNA degradation. A higher dose-dependent intracellular antioxidant and antibacterial activities of the nanohybrid is attributed to the synergistic effect of nanoceria and CDs. All these results clearly reflected that our synthesized CDs and their nanohybrids can be used for several biomedical applications.     

Mechanisms of action of irradiation on the conditioning of sewage sludge radical scavenging effects

Improvements in the application of ionizing radiation for the conditioning of sewage sludges are facilitated by knowledge of the governing processes. Accordingly, a model based on radiation chemical principles was developed and verified experimentally. Results of steady state irradiation and pulse radiolysis experiments, utilizing a variety of radical scavengers, demonstrated that the improvement of the dewatering and sedimentation characteristics of some sludges by gamma irradiation was produced mainly by the actions of the oxidizing OH radical on the suspended solids. The liquid and solid phases compete for OH as shown by the fact that the extent of conditioning of anaerobically digested sludge by gamma irradiation was inversely proportional to the “scavenging power”, namely, the product of the bimolecular rate constant for OH and the concentration of a given scavenger. The irradiation effect was modified to the identical extent, within experimental error, for the same value of the scavenging power, regardless of the particular scavenger employed. The attack of the OH radical on the organic solids produced, as anticipated, an increase in the concentration of organic compounds in the liquid phase. Pulse radiolysis experiments, utilizing competition between CNS⁻ and OH, demonstrated that the scavenging power of centrifugants of raw sludge was greater than that of anaerobically digested sludge. Results of steady state and pulse radiolysis experiments showed that the scavenging power of the suspended solids greatly exceeded that of liquid phase components. This work leads to recommendations for improvements in the design and operation of sludge irradiation facilities.     

牛磺酸对高血压和血管活性物质的影响

在原发性高血压(EH)患者、大鼠腹主动脉狭窄和高盐摄入引起高血压模型上,观察到口服牛磺酸治疗4周后均明显降低平均动脉压和收缩压,42.2%的患者血压恢复正常,并能抑制EH患者和高血压大鼠血浆内皮素(ET)、血管紧张素II(AII)水平的升高,增加高血压大鼠血浆降钙素基因相关肽(CGRP)和主动脉组织中的牛磺酸含量.以上结果表明,牛磺酸在降压作用同时伴有缩血管物质的降低和舒血管物质的增加,为以牛磺酸作为降血压辅助药物提供了依据.     

棉酚类衍生物的抗肿瘤作用

用小鼠Ｌｅｗｉｓ肺癌、肝癌和肉瘤１８０移植瘤模型研究了牛磺酸棉酚和巴比妥棉酚的抑瘤活性，并用细胞集落形成法研究了牛磺酸棉对人胃癌ＢＧＣ８２３和人肝癌ＳＭＭＣ７７２１细胞系的细胞毒作用。结果表明，牛磺酸棉酚２０．０ｍｇ／ｋｇ（ｉｐ）对Ｌｅｗｉｓ肺癌抑瘤率为４２．５％－６９．２％，２５．０ｍｇ／ｇｋ（ｉｐ）对肝癌腹小型小鼠生命延长率为７４．３％－１２０．％，对肉瘤１８０抑瘤率为２９．５％－３４．７／５     

铁、牛磺酸和精氨酸对大鼠肝纤维化的影响

应用放射性大鼠肝纤维化模型探讨铁剂在放射性肝纤维化发生中的作用及牛磺酸和精氨酸对肝脏的保护作用。方法将大鼠分为０Ｇｙ（正常对照）、３０Ｇｙ和３０Ｇｙ＋铁剂、３０Ｇｙ＋牛磺酸和３０Ｇｙ＋精氨酸组。于肝区照射后１，３个月分别检测血清铁离子、肝组织羟脯氨酸（Ｈｙｐ）和丙二醛（ＭＤＡ）含量以及应用偏振光显微镜观察肝内Ⅰ、Ⅲ胶原纤维的生成及分布特点。结果铁剂能明显增加肝组织中ＭＤＡ的含量和血清铁离子浓度。照射后１个月，铁剂组肝组织中Ｈｙｐ开始明显增加，进而肝脏中胶原纤维产生增多。牛磺酸和精氨酸能明显降低血清铁离子浓度，减少肝组织Ｈｙｐ含量。结论外源性铁剂能促进放射性肝纤维化的早期发生；牛磺酸和精氨酸可分别在一定程度上减轻放射性肝纤维化的病变     

牛磺酸对大鼠视网膜缺血再灌注保护作用的实验研究

 目的探讨缺血性视网膜病变中视网膜损伤的机制及诱因并研究牛磺酸的保护作用.方法选择健康Wistar大鼠108只,雌雄各半,随机分为6组,分别为正常对照组、假手术组、阳性对照组、β-丙氨酸处理组、牛磺酸处理组、维生素E处理组,通过升高眼内压造成视网膜缺血,持续60min后再灌注6 h做成高眼压模型,取视网膜进行神经节细胞凋亡测定、钙离子测定,并进行统计学分析.结果阳性对照组与牛磺酸用药组均有视网膜神经节细胞的凋亡,但牛磺酸组与阳性对照组比较,视网膜神经节细胞凋亡数明显减少(P＜0.05),同β-丙氨酸组比较也有显著性差异(P＜0.05);再灌注6 h后牛磺酸用药组Ca2+含量降低,同阳性对照组比较差异有统计学意义(P＜0.01).结论视网膜神经节细胞凋亡是视网膜缺血性病变的一个重要机制.钙离子是视网膜神经节细胞凋亡的重要诱因,牛磺酸有一定的保护作用.     

Experimental encephalomyelitis modulates inositol and taurine in the spinal cord of biozzi mice

In this high resolution magnetic resonance spectroscopic study of experimental allergic encephalomyelitis (EAE) and Semliki Forest virus (SFV) infection of the Bioui AB/H mouse, marked increases in the initially low levels of N-trimethyl compounds in the spinal cord were observed during probable demyelinating episodes. There was also a pronounced and reproducible modulation of the levels of taurine and myo-inositol during acute and again during chronic relapsing EAE. The ratio of N-acetyl-aspartate to creatine in the spinal cord of mice infected with the mutant M9 strain of SFV decreased to approximately 70% of that seen in normal mice.     

Mechanisms and imaging of football-related injuries

American football is a cutting/pivoting contact sport with high-speed and high-energy collisions among players on every play during games and training or practice. Although there have been constant rules and equipment changes in an attempt to limit the frequency of injuries, the incidence of musculoskeletal injuries remains high at every level of play in this sport. Imaging plays an important role in managing these players by helping in making an accurate diagnosis as well as guiding therapy and monitoring response to treatment. This article describes the major mechanisms and patterns of injury seen in these athletes, with a discussion of how imaging, primarily magnetic resonance imaging, assists the team physician in choosing a conservative versus surgical approach to recovery and return to play.     

A localized double-quantum filter for in vivo detection of taurine.

Noninvasive detection of taurine, an important amino acid involved in numerous physiological processes, by in vivo (1)H magnetic resonance (MR) spectroscopy is complicated by severe overlap of the taurine resonances with those of a number of other metabolites. Unambiguous differentiation of the taurine resonances requires spectral editing. In this study, the development of a localized spectral editing technique based on double-quantum filtering optimized for in vivo detection of taurine is described. The sequence recovers the taurine signal while substantially eliminating overlapping resonances and provides excellent three-dimensional spatial localization. The performance of the sequence is demonstrated both in phantoms and in rat brain in vivo. Magn Reson Med 42:454-460, 1999.     

Mechanisms of action of contrast media on cranial vessels. Comparison of diatrizoate, ioxaglate, iohexol, mannitol, and NaCl on rabbit basilar and ear arteries

The relaxant effects of the ionic contrast media diatrizoate and ioxaglate and the nonionic agent iohexol on the vascular wall were examined by a sensitive in vitro system. Control solutions of NaCl and mannitol were used to evaluate the relative importance of osmolality to the vasodilation response. The rabbit central ear artery and the basilar artery were precontracted by (1) potassium, causing depolarization of the sarcolemmal membrane, (2) noradrenaline, causing activation of alpha 1-adrenoceptors, and (3) histamine, causing activation of histamine H1 receptors. The contrast media caused concentration-dependent relaxation of both types of arteries; this effect was relatively insensitive to the agent used to precontract the vessels. Histamine-contracted arteries were thought more sensitive to the relaxant agents used than arteries contracted by potassium or noradrenaline. The relaxation induced by the contrast media correlates with the relaxation induced by equiosmolar amounts of NaCl or mannitol. Our results suggest that the artery dilator response seen after exposure to currently used contrast media is due primarily to changes in local osmolality rather than to a specific receptor involvement.     

Mechanisms of peripheral fatigue

Fatigue can be defined as the failure to maintain an expected power output. This is often an antecedent to some sports-related injury. It is important for those involved in physical performance to be familiar with the variety of mechanisms which can lead to fatigue. All too often, a single factor is described as the cause of fatigue when actually fatigue may be a combination of factors that contribute to the sequence of events that results in decreased performance. It may be suggested that every step in the chain of events that leads to voluntary contraction of skeletal muscle could be a culprit in fatigue. Peripheral sites and processes include the motor neuron, neuromuscular junction, sarcolemmal membrane, excitation-contraction coupling, accumulation of metabolites, or depletion of fuels. Physical training is frequently designed to delay the onset of fatigue. The actual mechanism(s) add to the specificity concept, that is, a "specificity of fatigue". To the performer, the end result is the same, the inability to maintain his or her expected level of performance or power output.     

持续性正加速度致意识丧失的机理及其监测

正在加速度引起的意识丧失（Ｇ－ＬＯＣ）是当胶威胁飞行安全的主要因素。综述了Ｇ＿ＬＯＣ的机理及其生理监测,慢增长率正加速度导致的意识丧失的机理主要大脑缺血／缺氧;快增长率正加速度导致物意识丧失可能与颅内高应力有关,但缺直接的实验证据。用于Ｇ－ＬＯＣ监测的生理指标中,眼水平动脉血压、脑氧饱和度等可能具有重要作用。     

Proton MR spectroscopy demonstration of taurine peaks in megalencephalic leukoencephalopathy with cysts.

Taurine is an amino acid. It has roles in neurotransmitter activities, facilitates synaptic connections, and possesses cyto-protective properties. Normally, it is invisible on proton MR spectroscopy acquired at low field strengths (i.e. 1.5T). In a patient with megalencephalic leukoencephalopathy with cysts (MLC), distinct taurine peaks centered at 3.35ppm were found on hybrid-CSI spectroscopy obtained at 1.5T with a long TE value (i.e. TE=135ms). This suggested increased concentrations of this metabolite in MLC. In this leukoencephalopathy taurine may be linked to a metabolic disturbance related with neurotransmitters associated with a disturbance in synaptic connections, and cyto-protective mechanisms. Further spectroscopic and clinical studies are required to evaluate this observation.