Antioxidative effect of the N-stearoylethanolamine in the heart tissue and blood plasma of rats under doxorubicin treatment

The influence of N-stearoylethanolamine on the alterated antioxidant enzyme activity in the heart tissue and blood plasma of rats under the doxorubicin treatment was investigated. It was shown that doxorubicin administration caused the decrease of antioxidant enzymes activity (superoxide dismutase and glutathione peroxidase) in the heart tissue. Administration of the NSE promoted the partial normalization of these enzymes activity. It was shown that doxorubicin treatment caused the increase of the urea and creatinine level in the blood plasma of experimental animals. The NSE administration normalized the level of the urea and did not affect creatinine level.     

超声对胃蛋白酶，胰蛋白酶，过氧化氢酶作用的研究

以胃蛋白酶,胰蛋白酶,过氧化氢酶溶液在超声处理下的酶活变化为指标研究超声对蛋白质作用的机理和影响因素。结果表明超声对蛋白质的破坏程度随着功率的升高或处理时间的延长而增加;三种酶在超声作用下酶活变化形式和程度各不同;浓度是影响超声对酶作用效果的一个重要因素,可通过调整酶溶液浓度来减少酶所受到的破坏程度。自由基清除剂甘露醇和非离子表面活性剂吐温-80可以对酶活在超声作用下起到一定的保护作用,说明自由基和超声空穴是超声破坏酶结构的重要机理,研究结果同时表明对于不同的酶,超声的破坏作用可能有不同的发挥主导作用机理。     

超声对酶的影响

超声对酶的影响与超声的强度和介质的性质有关。适宜的超声可提高酶促反应速度,较低强度的超声可提高酶的活性,而较高强度的超声会降低酶促反应速度甚至使酶失活。介质性质不同时,超声对酶活力的促进效果与稳定性不同。非极性介质中酶对于超声的抗性要优于水溶液。在较低强度的超声作用下,超声增加了底物的传质作用,并可导致酶分子的构象发生变化。     

Ultrasound assisted intensification of enzyme activity and its properties: a mini-review

Over the last decade, ultrasound technique has emerged as the potential technology which shows large applications in food and biotechnology processes. Earlier, ultrasound has been employed as a method of enzyme inactivation but recently, it has been found that ultrasound does not inactivate all enzymes, particularly, under mild conditions. It has been shown that the use of ultrasonic treatment at appropriate frequencies and intensity levels can lead to enhanced enzyme activity due to favourable conformational changes in protein molecules without altering its structural integrity. The present review article gives an overview of influence of ultrasound irradiation parameters (intensity, duty cycle and frequency) and enzyme related factors (enzyme concentration, temperature and pH) on the catalytic activity of enzyme during ultrasound treatment. Also, it includes the effect of ultrasound on thermal kinetic parameters and Michaelis–Menten kinetic parameters (k_m and V_max) of enzymes. Further, in this review, the physical and chemical effects of ultrasound on enzyme have been correlated with thermodynamic parameters (enthalpy and entropy). Various techniques used for investigating the conformation changes in enzyme after sonication have been highlighted. At the end, different techniques of immobilization for ultrasound treated enzyme have been summarized.     

超声在生物技术中应用的研究进展

超声波应用于生物技术是一个比较新的研究领域.许多研究发现,在有酶或细胞参与的情况下,一些过程可在超声作用下被激活.一般来说,较低强度的超声波可以通过改进反应物的质量传输机制,提高酶及固定酶的催化活性或加速细胞的新陈代谢过程.文中举例讨论了近年来超声在生物技术中应用的研究进展及前景.     

Low-level exertions of the neck musculature: a study of research methods.

Musculoskeletal neck discomfort is prevalent in many occupations and has been the focus of much research employing surface electromyography (sEMG). Significant differences in experimental methods among researchers make comparisons across studies difficult. The goal of the current research was to use empirical methods to answer specific methodological questions concerning use of sEMG in evaluation of the neck extensor system. This was accomplished in two studies. In Experiment 1, ultrasound technology was used to: (a) determine accessibility of m. splenius and semispinalis capitis with surface electrodes, (b) identify appropriate electrode locations for these muscles/muscle groups, and (c) illustrate potential benefits of using ultrasound in locating muscles/placing electrodes. Experiment 2 sought to assess effects of posture when normalizing sEMG data. Results from Experiment 1 showed no direct access to semispinalis capitis for surface electrodes; their activity can only be sampled as part of a group of muscles. In most subjects, m. splenius was found to be accessible to surface electrodes. Electrode placement recommendations are provided. Results of Experiment 2 showed significant differences in normalized EMG data between a posture-specific technique and a reference posture technique. Posture-specific normalization is recommended for accurately assessing the relative intensity of contractions of these muscles.     

Effect of N-stearoylethanolamine on the lipid peroxidation process and lipid composition of the rat liver in acute morphine intoxication

The effect of N-stearoylethanolamine (NSE) on the lipid peroxidation process, antioxidant enzymes activity, phospholipid and fatty acid content in the rat liver tissues under acute morphine administration was studied. It was shown that morphine administration (30 mg/kg of body weight) caused an increase of the amount of thiobarbituric acid reactive substances (TBARS), alteration of antioxidant enzymes activity, decrease the protein level, quantity of total lipids and phospholipids, phosphatidylcholine, cholesterol esters; altered the content of some individual fatty acids. NSE administration (50 mg/kg of body weight) promoted normalization of the antioxidant enzymes activity and prevented the TBARS accumulation and decreased the total lipid and phospholipid quantity, increased the content of free and total cholesterol, corrected the level of free and individual fatty acids. It was assumed that NSE possessed antioxidative, membranoprotective and adaptive properties.     

The influence of N-stearoylethanolamine on the activity of antioxidant enzymes and on the level of stable NO metabolites in the rat testes and blood plasma at the early stages of streptozotocine-induced diabetes

The influence of N-stearoylethanolamine was investigated on the activity of enzymes of antioxidant protection and content of stable metabolites of nitric oxide (NO) in the testes and plasma of rats at the early stages of development of streptozotocine-induced diabetes mellitus. It was shown that the activity of superoxide dismutase, catalase is reduced in the plasma and testes of animals with streptozotocin-induced (50 mg/kg) diabetes (blood glucose 8-10 mmol/L). A significant increase in the amount of nitrite and nitrate anions was revealed in the plasma of rats, while only the level of nitrite was significantly changed in the testes of animals. The per os administration of the NSE aqueous suspension in a dose of 50 mg/kg during 10 days to the rats with induced diabetes contributed to the normalization of catalase activity in the testis, which correlated with a decrease in the amount of TBA-reacting products and activity of superoxide dismutase and catalase in the blood plasma of animals; the use of NSE also contributed to the reduction of nitrite content in the gonads and to normalization of both nitrite and nitrate in the blood plasma of rats. The NSE administration to intact animals caused an increase in superoxide dismutase activity and significantly reduced the content of stable NO metabolites in the blood plasma of animals.     

Activity of phosphatases and succinic dehydrogenase in the trigeminal ganglion of the corticosteroid-treated mouse.

Immature mice were treated for 21 days with daily doses of triamcinolone diacetate. The trigeminal ganglion was studied enzymatically for the activity of alkaline phosphatase, acid phosphatase, ATPase and succinic dehydrogenase. It became apparent that the prolonged treatment with a potent corticosteroid hormone did not affect significantly the in vivo activity of the above enzymes. Some enzymes even appeared to have increased their intracellular activity. The heterogeneous effect of corticosteroid upon their peripheral target organs is discussed.     

Essentiality of the active-site arginine residue for the normal catalytic activity of Cu,Zn superoxide dismutase.

Chemical modification of bovine and yeast Cu,Zn superoxide dismutases with phenylglyoxal diminishes the catalytic activities by greater than or equal to 98%, and treatment of these enzymes with butanedione plus borate leads to greater than or equal to 96% inactivation. The activity loss is accompanied by the modification of less than two arginine residues per subunit with no concomitant loss of Cu or Zn. The phenylglyoxal-modified enzymes require at least a 20-fold greater concentration of cyanide for 50% inhibition than do the corresponding native enzymes. Polyacrylamide-gel electrophoresis and activity staining of the phenylglyoxal-inactivated enzymes demonstrate that the residual activity is largely associated with modified forms that bear lower net positive charge than the native superoxide dismutases.     

Stimulatory effects of low intensity ultrasound on the growth kinetics and metabolic activity of Lactococcus lactis subsp. Lactis

The present study was carried out to investigate the effects of low intensity ultrasound (20% and 30% amplitudes for 3 min and 5 min) on the growth kinetics and metabolic activity of Lactococcus lactis subsp. Lactis. The results revealed that the viable cell counts increased by 6.21–21.82% under ultrasound treatment. Confocal scanning laser microscopy showed 3.03–22.88% reduction in the percentage of intact cells after ultra-sonication. The specific growth rate of ultrasonicated L. lactis subsp. Lactis also increased by 7.09–23.22%. The pH values and titratable acidity were lower and higher, respectively, for most treatments. The treatments increased β-galactosidase activity. This was accompanied with a faster rate in lactic acid yield. The protein concentrations significantly decreased with increasing ultrasound amplitude and duration of irradiation, whilst at the same conditions the degree of protein hydrolysis was higher. Results suggest that ultrasound can stimulate the growth of L. lactis subsp. Lactis and its metabolic activity. Therefore, ultrasound can potentially play a significant role in stimulating fermentative activities of starter cultures and may successfully be employed in fermentation industries.     

Influence of antitumor system rhenium-platinum on biochemical state of the liver

Influence of the antitumour rhenium-platinum system on biochemical liver characteristics in the model of tumor growth (Guerin carcinoma) was studied and possible hepatoprotective activity of rhenium cluster compounds when introducing them in different forms was shown, that was confirmed by decreasing of diagnostic enzymes activity in blood (aminotransferase--AST 6 times and ALT 5.6 times, lactatedehydrogenase 4.9 times, gamma-glutamyltranspeptidase 3.6 times) and normalization of morphological state of the liver cells. The hepatoprotective activity of the cluster rhenium compound with adamanthyl ligands was confirmed in the model of acute toxic hepatitis. Introduction of this compound led to reduction of the concentration of MDA in homogenates of liver tissue (2 times), and in blood plasma (3.8 times); to reduction of levels of diagnostic liver enzymes in blood--AST and ALT 5.8 and 5.5 times respectively in comparison with control group. Some aspects of the mechanism of hepatoprotection were discussed, that included the presence of conjugated systems around the quadrupol rhenium-rhenium bond and alkyl radicals with significant positive inductive effects.     

A non-MVC EMG normalization technique for the trunk musculature: Part 2. Validation and use to predict spinal loads.

Estimates of the amount of force exerted by a muscle using electromyography (EMG) rely partially upon the accuracy of the reference point used in the normalization technique. Accurate representations of muscle activities are essential for use in EMG-driven spinal loading models. The expected maximum contraction (EMC) normalization method was evaluated to explore whether it could be used to assess individuals who are not capable of performing a maximum exertion such as a person with a low back injury. Hence, this study evaluated the utility of an EMG normalization method (Marras and Davis, A non-MVC EMG normalization technique, Part 1, method development. Journal of Electromyography and Kinesiology 2000) that draws upon sub-maximal exertions to determine the reference points needed for normalization of the muscle activities. The EMC normalization technique was compared to traditional MVC-based EMG normalization by evaluating the spinal loads for 20 subjects (10 males and 10 females) performing dynamic lifts. The spinal loads (estimated via an EMG-assisted model) for the two normalization techniques were very similar with differences being <8%. The model performance variables indicated that both normalization techniques performed well (r(2)>0.9 and average error below 6%) with only the muscle gain being affected by normalization method as a result in different reference points. Based on these results, the proposed normalization technique was considered to be a viable method for EMG normalization and for use in EMG-assisted models. This technique should permit the quantitative evaluation of muscle activity for subjects unable to produce maximum exertions.     

Modulation of the activity of insulin-dependent enzymes of lipogenesis by glucocorticoids.

Administration of triamcinolone or dexamethasone to rats led to a prompt, marked and persistent rise in liver acetyl-CoA carboxylase activity. The activity of fatty acid synthetase increased to a lesser extent and after a more prolonged glucocorticoid treatment, whereas the changes in that of NADP-malate dehydrogenase and ATP-citrate lyase were not appreciable. The overall channeling of [1-14-C]acetyl-CoA to fatty acids was enhanced. The triamcinolone effect on acetyl-CoA carboxylase activity appeared to be dependent on the coincident hyperinsulinemia since it was not obtained in alloxan-diabetic rats, whereas the alanine-aminotransferase-inducing effect of this hormone was additive to that of insulin deficiency. In adipose tissue triamcinolone treatment caused a reduction in the activity of all lipogenesis enzymes and blunted their response to insulin administration. The antagonism of glucocorticoids toward insulin, selectively modulating the responses of the insulin-sensitive enzymes in liver and adipose tissue is discussed. The rise in hepatic lipogenic capacity, through the retention of the ability of insulin to induce acetyl-CoA carboxylase, may be physiologically important in restraining the ketogenesis from acetyl-CoA despite the increased fat utilization during glucocorticoid excess.     

Antioxidant activity of Aulosira fertilisima on CCl4 induced hepatotoxicity in rats

Free radicals cause cell injury, when they are generated in excess or when the antioxidant defense is impaired. Carbon tetrachloride (CCl4) is used as a model for liver injury. In this study antioxidant activity of ethanol extract of A. fertilisima (EEA) was investigated using CCl4 intoxicated rat liver as the experimental model. Oral administration of EEA at a dose of 100 mg/kg body weight, for 14 consecutive days, the rate of the production of antioxidant enzymes like super oxide dismutase, catalase, glutathione peroxidase and glutathione transferase in rats compared to the CCl4 treated group without any supporting treatment. Liver damage is detected by the measurement of the activities of serum enzymes like aspartate aminotransferase, alanine aminotransferase, gamma glutamyl transpeptidase and alkaline phosphatase which were released in to the blood from damaged cells. The normalization of these enzymes levels was observed in rats treated with EEA (100 mg/kg body weight) by reducing the leakage of the above enzymes in to the blood. The findings provide a rationale for further studies on isolation of active principles and its pharmacological evaluation. Protection offered by silymarin (standard reference drug) seemed relatively greater.     

Glutamyl transferase and acetylcholinesterase activity in various areas of the rat brain in alcoholic intoxication

Albino mongrel rats were used for the determination of the gamma-glutamyl transferase (gamma-GTF) and acetylcholine esterase (AChE) activities in various brain areas (cerebral hemispheres, cerebellum, hippocampus, brain stem) during acute (1.5; 4 and 6 g/kg i. p.) and chronic (15 months) alcoholic intoxication and alcohol withdrawal (24-48 h, 4 and 8 days). An increase or a decrease in the activity of these two enzymes in the various rat brain areas depends on the dose of ethanol and the time of its action. The activity of gamma-GTF grew in all brain areas during chronic ethanol intoxication; the activity of AChE was also enhanced in three brain areas but it was diminished in cerebral hemispheres. Alcohol withdrawal caused diverse changes in the activities of these two enzymes in various areas of the brain. A tendency to normalization of the gamma-GTF and AChE activities is manifested 4-8 days after alcohol withdrawal.     

The influence of exogenous and of membrane-bound phosphatidate concentration on the activity of CTP: phosphatidate cytidylyltransferase and phosphatidate phosphohydrolase.

Rat liver microsomes were treated with phospholipase D to obtain microsomal membranes with varying amounts of membrane-bound phosphatidate. This treatment did not impair the activity of two microsomal-bound enzymes acting with phosphatidate as substrate, i.e. CTP: phosphatidate cytidylyltransferase and phosphatidate phosphohydrolase. The dependency of the activity of these enzymes on the concentration of membrane-bound phosphatidate was determined. Both enzymes showed a linear increase in activity with membrane-bound phosphatidate concentrations up to at least 100 nmol phosphatidate/mg microsomal protein. These results indicate that both enzymes have a large reserve capacity and suggest that the enzymes are operating intracellularly, i.e. at phosphatidate concentrations of 5-10 nmol/mg endoplasmic reticulum protein, far below their maximal capacity. The ratio of phosphatidate conversion into CDP-diglyceride and 1,2-diglyceride seems to be constant for a large range of membrane-bound phosphatidate concentrations. The membrane-bound enzymes cannot utilize phosphatidate substrate present in heat-denatured membranes, but are active on phosphatidate incorporated into membranes of phospholipid vesicles.     

A non-MVC EMG normalization technique for the trunk musculature: Part 1. Method development.

Normalization of muscle activity has been commonly used to determine the amount of force exerted by a muscle. The most widely used reference point for normalization is the maximum voluntary contraction (MVC). However, MVCs are often subjective, and potentially limited by sensation of pain in injured individuals. The objective of the current study was to develop a normalization technique that predicts an electromyographic (EMG) reference point from sub-maximal exertions. Regression equations predicting maximum exerted trunk moments were developed from anthropometric measurements of 120 subjects. In addition, 20 subjects performed sub-maximal and maximal exertions to determine the necessary characteristic exertions needed for normalization purposes. For most of the trunk muscles, a highly linear relationship was found between EMG muscle activity and trunk moment exerted. This analysis determined that an EMG-moment reference point can be obtained via a set of sub-maximal exertions in combination with a predicted maximal exertion (expected maximum contraction or EMC) based upon anthropometric measurements. This normalization technique overcomes the limitations of the subjective nature for the MVC method providing a viable assessment method of individuals with a low back injury or those unwilling to exert an MVC as well as could be extended to other joints/muscles.     

超声波在生物工程中的应用

研究发现在酶和细胞催化的生物反应过程中,较低强度的超声作用可提高酶的催化活性或加速细胞的代谢过程。本文主要简述超声波作用的物理机制并对其在生物工程中的应用前景进行讨论。     

Peculiarities of metabolism of UV-irradiated lymphocytes

The influence of UV-light (240-390 nm) at a dose of 151 and 755 J/m2 on the functional properties of lymphocyte metabolism key enzymes from donors' human blood: lactate dehydrogenase (LDH), cytochrome c oxidase, succinate dehydrogenase (SDH), Ca2(+)-ATPase of plasma membranes has been investigated. It has been revealed that photoinactivation of enzymes immediately after UV-irradiation which leads to the decrease of the ATP content in lymphocytes is replaced by the increased activity of the enzymes under investigation during daily incubation of lymphocytes. As a result, the level of ATP in photo-modified lymphocytes does not differ from that in native cells before incubation. This indicates the normalization of biochemical processes in lymphocytes influenced by UV-light applied in autotransfusion of UV-irradiated blood.