Protective effect of Mesona procumbens against tert-butyl hydroperoxide-induced acute hepatic damage in rats

The protective effect of Hsian-tsao (Mesona procumbens Hemsl.) and its active compounds on liver damage was evaluated using the model of tert-butyl hydroperoxide (t-BHP)-induced acute hepatic damage in rats. Male Sprague-Dawley rats (200 +/- 10 g) were orally pretreated with a water extract of Hsian-tsao (WEHT) (0.1, 0.5, and 1.0 g/kg) or caffeic acid (0.1 g/kg of body weight) for 13 days before a single dose of t-BHP (0.2 mmol/kg, intraperitoneally) to each animal, and the rats were sacrificed 18 h later by decapitation; blood samples were collected for the assays of serum biochemical values. The livers were excised from the animals and assayed for oxidative injury, antioxidant enzyme, and pathological histology. The result showed that the oral pretreatment of WEHT (0.1, 0.5, and 1.0 g/kg) or caffeic acid (0.10 g/kg) before t-BHP (0.2 mmol/kg) treatment significantly lowered the serum levels of the hepatic enzyme markers (alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) and reduced oxidative stress of the liver by evaluation of malondialdehyde, glutathione, 8-hydroxy-2'-deoxyguanosine, glutathione peroxidase, and glutathione reductase. The histopathological evaluation of the rat livers showed that WEHT and caffeic acid reduced the incidence of liver lesions including cloudy swelling, pyknosis, and cytolysis induced by t-BHP in rats. On the basis of the results of this study, it can be speculated that M. procumbens protects liver against t-BHP-induced hepatic damage in rats.     

Water mobility in multicomponent model media as studied by 2H and 17O NMR

Molecular mobility of water was studied in a microbiological media containing complex and heterogeneous mixtures of cellulose, l-sorbose, and orange serum broth (OSB) using (2)H and (17)O high-resolution NMR. All mixtures showed Lorentian (17)O NMR spectra but complex (2)H NMR line shapes. Sorbose, when solubilized, caused line-narrowing where as cellulose-OSB mixtures showed wide peaks with flat plateaus. Presence of liquid or solvent water had a profound effect on a marked increase in T(2) relaxation time observed in sorbose-containing samples. (17)O NMR data were not composition dependent, while (2)H NMR data were highly sorbose dependent.     

Inhibitory effect of naturally occurring flavonoids on the formation of advanced glycation endproducts

The objective of this study was to investigate the inhibitory effect of naturally occurring flavonoids on individual stage of protein glycation in vitro using the model systems of delta-Gluconolactone assay (early stage), BSA-methylglyoxal assay (middle stage), BSA-glucose assay, and G.K. peptide-ribose assay (last stage). In the early stage of protein glycation, luteolin, qucertin, and rutin exhibited significant inhibitory activity on HbA1C formation (p < 0.01), which were more effective than that of aminoguanidine (AG, 10 mM), a well-known inhibitor for advanced glycation endproducts (AGEs). For the middle stage, luteolin and rutin developed more significant inhibitory effect on methylglyoxal-medicated protein modification, and the IC50's were 66.1 and 71.8 microM, respectively. In the last stage of glycation, luteolin was found to be potent inhibitors of both the AGEs formation and the subsequent cross-linking of proteins. In addition, phenyl-tert-butyl-nitron served as a spin-trapping agent, and electron spin resonance (ESR) was used to explore the possible mechanism of the inhibitory effect of flavonoids on glycation. The results indicated that protein glycation was accompanied by oxidative reactions, as the ESR spectra showed a clear-cut radical signal. Statistical analysis showed that inhibitory capability of flavonoids against protein glycation was remarkably related to the scavenging free radicals derived from glycoxidation process (r = 0.79, p < 0.01). Consequently, the inhibitory mechanism of flavonoids against glycation was, at least partly, due to their antioxidant properties.     

Main Characteristics of Statistical Data and the Statistical System for Wood and Wood-processing Products in Vietnam

This paper describes the characteristics of data about wood and wood-processing products published in Vietnam. The characteristics include inconsistency of data published by major data sources, lack of necessary data, and irregular publication frequency. Reasons are identified for the existence of the above characteristics of data for the wood and wood-processing industries, including recent changes in the functions of state statistical organizations and unclear concepts of data published. These characteristics create difficulties for researchers and policy-makers working at the Ministry of Agriculture and Rural Development for analysing policies and establishing supply targets for the wood and wood-processing industries in 5-year economic plans. To improve the statistical system, co-operation between state organisations and the information network (e.g. computers and internet connection) requires strengthening.     

中国植物志第九卷第三分册所找述的种—Psathyrostachys Ianugínosa(Trin.) Nevski的订正

郭本兆教授提供的编志时所用的Psathyrostachys lanuginosa(Trin.)Nevski标本都是错订的。它们应当是Psathyrostachys stoloniformis Baden,Linde—Laursen et Dewey。该书描述的P.lanuginosa应订正为穗长10—30毫米,宽4—9毫米。穗轴节无明显翅状构造。该书描述的0.5毫米的翅状构造,仅见于P.stoloniformis的穗轴节的两侧。P.lanuginosa只分布于新疆的富蕴、青河两县。甘肃与青海分布的都是P.stoloniformis。该书图6:10—12所绘的不是P.lanugi—nosa,而是P.stoloniformis。     

陆地棉纤维不同强度指标的相关与变异初探

对陆地棉不同纤维强度类型品种的研究表明,单纤维强力,零隔距比强度,3.2毫米隔距比强度与断裂长度4项强度表示的不同指标的差异,品种间变化趋势相似;但环境影响表明,断裂长度与单纤维强力变化趋势相似,而与3.2毫米隔距比强度可能是概念不同的物理量(克力/特克斯),并非决定于同一层次的纤维结构。对纤维强度指标的变异分析证明,除鲁棉6号与PD 9223两品种在一定范围内表现了圆锥体层次愈多,铃期温度愈低。零隔距比强度愈高外,其它品种与其它强度指标的变异与环境和营养条件无关。供试品种中,对环境反应敏感的为鲁棉6号。在4项强度指标中,两项比强度指标仅受胞壁结构影响,变异系数小;单纤维强力与断裂长度受纤维干重与胞壁结构双重影响,变异系数大。     

Evidence that the reactivity of the martian soil is due to superoxide ions

The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.     

Structural basis of type II topoisomerase inhibition by the anticancer drug etoposide

Type II topoisomerases (TOP2s) resolve the topological problems of DNA by transiently cleaving both strands of a DNA duplex to form a cleavage complex through which another DNA segment can be transported. Several widely prescribed anticancer drugs increase the population of TOP2 cleavage complex, which leads to TOP2-mediated chromosome DNA breakage and death of cancer cells. We present the crystal structure of a large fragment of human TOP2β complexed to DNA and to the anticancer drug etoposide to reveal structural details of drug-induced stabilization of a cleavage complex. The interplay between the protein, the DNA, and the drug explains the structure-activity relations of etoposide derivatives and the molecular basis of drug-resistant mutations. The analysis of protein-drug interactions provides information applicable for developing an isoform-specific TOP2-targeting strategy.     

Multiple glassy states in a simple model system

Experiments, theory, and simulation were used to study glass formation in a simple model system composed of hard spheres with short-range attraction ("sticky hard spheres"). The experiments, using well-characterized colloids, revealed a reentrant glass transition line. Mode-coupling theory calculations and molecular dynamics simulations suggest that the reentrance is due to the existence of two qualitatively different glassy states: one dominated by repulsion (with structural arrest due to caging) and the other by attraction (with structural arrest due to bonding). This picture is consistent with a study of the particle dynamics in the colloid using dynamic light scattering.     

Long base line interferometry: a new technique

The technique of using magnetic-tape recorders and atomic frequency standards to operate two widely separated radio telescopes as a phase-coherent interferometer when the stations have no radio-frequency connecting link has been successfully tested at the National Research Council of Canada's Algonquin Radio Observatory.