谷胱甘肽S转移酶π(GST-π)在非霍奇金淋巴瘤中的表达及意义

目的探讨谷胱甘肽S转移酶π(GST-π)与非霍奇金淋巴瘤(NHL)分期及病理分型及预后的关系。方法对30例NHL患者进行谷胱甘肽S转移酶π(GST-π)检测。结果中高度恶性与低度恶性组间谷胱甘肽转化酶差异有显著性,谷胱甘肽S转移酶π阳性,提示预后不良。结论GST-π是预测NHL分期、恶性程度及预后的重要指标。

Effects of dietary menadione on the activity of antioxidant enzymes in abalone, Haliotis discus hannai Ino

A 240-day growth experiment in a re-circulating water system was conducted to investigate the effects of dietary menadione on the growth and antioxidant responses of abalone Haliotis discus hannai Ino. Triplicate groups of juvenile abalone (initial weight: 1.19 ± 0.01 g; shell length: 19.23 ± 0.01 mm) were fed to satiation with 3 semi-purified diets containing 0, 10, and 1 000 mg menadione sodium bisulfite (MSB)/kg, respectively. Results show that there were no significant differences in the rate of weight gain or in the daily increment in shell length of abalone among different treatments. Activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione S-transferase (GST) and glutathione reductase (GR) in viscera were significantly decreased with dietary menadione. However, activities of these enzymes except for GPX in muscle were increased. Therefore, antioxidant responses of abalone were increased in muscle and decreased in viscera by dietary menadione.

Role of MGST1 in reactive intermediate-induced injury

Microsomal glutathione transferase (MGST1, EC 2.5.1.18) is a membrane bound glutathione transferase extensively studied for its ability to detoxify reactive intermediates, including metabolic electrophile intermediates and lipophilic hydroperoxides through its glutathione dependent transferase and peroxidase activities. It is expressed in high amounts in the liver, located both in the endoplasmic reticulum and the inner and outer mitochondrial membranes. This enzyme is activated by oxidative stress. Binding of GSH and modification of cysteine 49 (the oxidative stress sensor) has been shown to increase activation and induce conformational changes in the enzyme. These changes have either been shown to enhance the protective effect ascribed to this enzyme or have been shown to contribute to cell death through mitochondrial permeability transition pore formation. The purpose of this review is to elucidate how one enzyme found in two places in the cell subjected to the same conditions of oxidative stress could both help protect against and contribute to reactive oxygen species-induced liver injury.

Melatonin ameliorates experimental hepatic fibrosis induced by carbon tetrachloride in rats

AIM:To investigate the protective effects of melatonin on carbon tetrachloride(CCl4)-induced hepatic fibrosis in experimental rats.METHODS:All rats were randomly divided into normal control group,model control group treated with CCl4 for 12 wk,CCl4+NAC group treated with CCl4+NAC(100 mg/kg,i.p.)for 12 wk,CCl4+MEL-1 group treated with CCl4+melatonin(2.5 mg/kg)for 12 wk,CCl4+MEL-2 group treated with CCl4+ melatonin(5.0 mg/kg)for 12 wk,and CCl4+MEL-3 group treated with CCl4+melatonin(10 mg/kg).Rats in the treatment groups were injected subcutaneously with sterile CCl4(3 mL/kg,body weight)in a ratio of 2:3 with olive oil twice a week.Rats in normal control group received hypodermic injection of olive oil at the same dose and frequency as those in treatment groups.At the end of experiment,rats in each group were anesthetized and sacrificed.Hematoxylin and eosin(HE)staining and Van Gieson staining were used to examine changes in liver pathology.Serum activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST)and protein concentration weremeasured with routine laboratory methods using an autoanalyzer.Hydroxyproline(HYP)content in liver and malondialdehyde(MDA)and glutathione peroxidase(GPx)levels in liver homogenates were assayed by spectrophotometry.Serum hyaluronic acid(HA),laminin(LN),and procollagenⅢN-terminal peptide(PⅢNP)were determined by radioimmunoassay.RESULTS:Pathologic grading showed that the fibrogenesis was much less severe in CCl4+MEL3 group than in model control group(u=2.172,P<0.05),indicating that melatonin(10 mg/kg)can significantly ameliorate CCl4-induced hepatic fibrotic changes.The serum levels of ALT and AST were markedly lower in CCl4+MEL treatment groups(5,10 mg/kg)than in model control group(ALT:286.23 ±121.91 U/L vs 201.15±101.16 U/L and 178.67 ±103.14 U/L,P=0.028,P=0.007;AST:431.00 ±166.35 U/L vs 321.23±162.48 U/L and 292.42 ±126.23 U/L,P=0.043,P=0.013).Similarly,the serum laminin(LN)and hyaluronic acid(HA)levels and hydroxyproline(HYP)contents in liver were significantly lower in CCl4+MEL-3 group(10 mg/kg)than in model control group(LN:45.89±11.71μg/L vs 55.26± 12.30μg/L,P=0.012;HA:135.71±76.03μg/L vs 201.10±68.46μg/L,P=0.020;HYP:0.42±0.08 mg/g tissue vs 0.51±0.07 mg/g tissue,P=0.012).Moreover,treatment with melatonin(5,10 mg/kg)significantly reduced the MDA content and increased the GPx activity in liver homogenates compared with model control group(MDA:7.89±1.49 noml/mg prot vs 6.29±1.42 noml/mg prot and 6.25±2.27 noml/mg prot,respectively,P=0.015,P=0.015;GPx:49.13± 8.72 U/mg prot vs 57.38±7.65 U/mg prot and 61.39± 13.15 U/mg prot,respectively,P=0.035,P=0.003).CONCLUSION:Melatonin can ameliorate CCl4-induced hepatic fibrosis in rats.The protective effect of melatonin on hepatic fibrosis may be related to its antioxidant activities.

Biomarker responses in the bivalve Chlamys farreri to the water-soluble fraction of crude oil

To investigate the effect of the water soluble fraction of crude oil(WSF) on marine bivalves, the scallop C hlamys farreri was exposed to three WSF concentrations(0.18 mg/L, 0.32 mg/L, and 0.51 mg/L, respectively) in seawater. Petroleum hydrocarbon contents in scallops and a suite of enzymes [7-Ethoxyresorufin-O-deethylase(EROD), aryl hydrocarbon hydroxylase(AHH), glutathione S-transferase(GST), and glutathione peroxidase(GPx)] in gills and digestive glands were monitored over 10 days. The results revealed that WSF affected the activity of the four enzymes in the gills and digestive glands. EROD activity in the gills was significantly induced in most individuals of the three test groups, while in the digestive gland it was significantly induced in the low-concentration group within 4 days but was inhibited in the middle- and high-concentration groups on days 1, 4, and 10. AHH activity in the gills of all treatment groups was significantly induced on day 1. In the digestive gland, AHH activity was induced in most individuals from the treatment groups. In all treatment groups, GST activity was significantly inhibited from days 2 to 10 in the gills and was induced after day 4 in the digestive gland. GPx activity in the gills was significantly inhibited throughout the exposure period in all treatment groups. There was no overall significant difference in GPx activity in the digestive gland between the control and treatment groups. Our results also revealed that petroleum hydrocarbon concentrations in the tissues increased linearly with exposure time. EROD activity in the digestive gland and GST and GPx activity in the gill tissue were negatively correlated with petroleum hydrocarbon body burden. These enzymes play important roles in detoxification and can act as potential biomarkers for monitoring petroleum hydrocarbon contaminants in the marine environment.

GLUTATHIONE S TRANSFERASE-π EXPRESSION IN HU- MAN GASTRIC CANCER AND ITS RELATIONSHIP TO CHEMOSENSITIVITY

Objective To investigate the expression of glutathione S transferase π(GST-π) in gastric carcinoma tissue sections,and its relationship to the clinicopathological parameters and the results of chemosensitivity testing on the freshly purified human gastric cancer cells. Methods Expression of GST-π in 39 gastric cancer specimens was detected by immunohistochemical method.Simultaneously,the chemosensitivity of individual cases to 5-FU,CDDP,MMC and ADM was determined by using MTT colorimetric assay. Results The percentage of positive GST-π was 66.7%,while that of negative was 33.3%.No significant correlation between the expression of GST-π and clinicopathologic features was observed.There was a statistical significance of the correlation of GST-π expression with drug resistance of gastric cancer to CDDP and MMC. Conclusion Over-expression of GST-π in gastric cancer tissue may be related to the drug resistance to CDDP and MMC.It is therefore important to select carefully the optimal anticancer drug for patients with highly positive GST-π expression.