Antidiabetic effect of a newly identified component of Opuntia dillenii polysaccharides.

The aim of this study was to determine the most effective hypoglycemic component of polysaccharides from Opuntia dillenii Haw. by preliminary screening and to specifically study the antidiabetic effects of O. dillenii polysaccharide (ODP)-Ia in mice with streptozotocin (STZ)-induced diabetes. Three kinds of ODPs - ODP-Ia, ODP-Ib, and ODP-II' - were isolated by using an ultrasonic extraction method and diethylaminoethyl (DEAE)-Sepharose fast-flow column chromatography. The mice were administered ODPs for 3 weeks. Gavage administration of ODP-Ia significantly decreased (P<0.05) their intake of food and water; the fasting levels of blood glucose (BG), total cholesterol (TC), triglycerides (TGs), plasma urea nitrogen (PUN), and malondialdehyde (MDA); and the activity of glucose-6-phosphatase (G-6-Pase). In contrast, it significantly increased (P<0.05) the body weights, hepatic glycogen (HG) levels, high-density lipoprotein cholesterol (HDL-C) levels, and the hepatic superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in diabetic mice. However, ODP-Ia did not significantly increase insulin levels in the mice with STZ-induced diabetes. We propose that ODP-Ia exerts its antihyperglycemic effect by protecting the liver from peroxidation damage and by maintaining tissue function, thereby improving the sensitivity and response of target cells in diabetic mice to insulin.

Effects of selenium and methionine supplementation of breeder hen diets on selenium concentration and oxidative stability of lipids in the thigh muscles of progeny.

The effects of dietary supplementation to female chickens with selenium (Se) and methionine (Met) on the next generation were studied. Lang-shan breeding hens (450) were obtained at 52 wk of age and randomly allotted to 9 treatments; 5 replicates of each treatment were carried out. The breeders were fed a basal corn-soybean meal diet (0.13 mg Se/kg) supplemented with 0, 0.30, or 0.60 mg/kg Se from Sel-Plex and 0.32%, 0.40%, or 0.54% Met for the 30-d adapting period and 70-d experiment period. Se and glutathione (GSH) concentrations, glutathione peroxidase (GSH-Px) activity, and the oxidative stability of muscular lipids of 90-d progeny were determined by testing the TBARS values. When breeders received the highest levels of Met or Se, GSH-Px activity was decreased, the Se concentration and the oxidative stability of muscular lipids were increased with the supplementation of Se or Met. When breeder hens were given a Met-deficient diet, supplementing with Se decreased the Se deposition in progeny thigh. With regard to lipid oxidation, 0.3 mg/kg maternal dietary Se supplementation decreased the oxidative stability of muscle lipid and 0.6 mg/kg Se supplementation showed no difference from the control. When breeders were fed a Se-deficient diet, the GSH-Px activity was increased significantly and the oxidative stability of progeny muscles was decreased with the supplementation of Met. It was concluded that supplementation of the maternal diet with higher Se and Met can increase Se deposition in progeny muscle and lead to more effective protection against lipid oxidation in progeny thighs.

Production and synthetic dyes decolourization capacity of a recombinant laccase from Pichia pastoris.

AIMS: To produce and purify a recombinant laccase from Pichia pastoris and to test its ability in decolourization of synthetic dyes. METHODS AND RESULTS: A cDNA encoding for a laccase was isolated from Pycnoporus sanguineus and was expressed in P. pastoris strain SMD1168H under the control of the alcohol oxidase (AOX1) promoter. The laccase native signal peptide efficiently directed the secretion of the recombinant laccase in an active form. Factors influencing laccase expression, such as cultivation temperature, pH, copper concentration and methanol concentration, were investigated. The recombinant enzyme was purified to electrophoretic homogeneity, and was estimated to have a molecular mass of about 62.8 kDa. The purified enzyme showed a similar behaviour to the native laccase produced by P. sanguineus. Four different synthetic dyes including azo, anthraquinone, triphenylmethane and indigo dyes could be efficiently decolourized by the purified recombinant laccase without the addition of redox mediators. CONCLUSIONS: Heterologous production of P. sanguineus laccase in P. pastoris was successfully achieved. The purified recombinant laccase could efficiently decolourize synthetic dyes in the absence of mediators. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first report on the synthetic dye decolourization by the recombinant P. sanguineus laccase. The decolourization capacity of this recombinant enzyme suggested that it could be a useful biocatalyst for the treatment of dye-containing effluents.

[The changes in plasma arginine-vasopressin in patients with essential hypertension and the correlation with patient's condition].

The levels of plasma arginine-vasopressin (AVP) in 80 patients with essential hypertension were measured, and its impact on the disease and its clinical significance were studied. The results showed that: (1) The levels of plasma AVP in patients with essential hypertension were significantly higher than that in normotensive subjects (P < 0.001). It dropped to normal level after antihypertensive drugs. (2) The concentrations of plasma AVP in both hypertensive subjects and normotensive subjects were not correlated with age and sex (P < 0.05). (3) The concentration of plasma AVP in patients with essential hypertension was the highest in stage III, the lowest in stage I, and middle in stage II. (4) The levels of plasma AVP in patients with malignant hypertension were significantly higher than that in patients with benign hypertension (P < 0.05). A positive correlation was found between the levels of plasma AVP and blood pressure (r = 0.3398, P < 0.01). (5) The concentrations of plasma AVP in hypertensive subjects with ventricular hypertrophy were higher than that in hypertensive subjects with out ventricular hypertrophy (P < 0.05). (6) The concentrations of plasma AVP in hypertensive subjects with heart failure were significantly higher than that in hypertensive subjects with out heart failure (P < 0.001). The results suggest that AVP has a role in the pathogenesis of hypertension, hypertension complicated with ventricular hypertrophy and hypertension complicated with heart failure. The levels of plasma AVP may be viewed as an index of the patient's condition in hypertensive subjects.

[Activity of plasma dopamine-beta-hydroxylase and urine excretion of catecholamines in patients with deficiency-cold and deficiency-heat syndromes].

Spectrophotometric assay of plasma dopamine-beta-hydroxylase (D beta H) activity and fluorospectrophotometric assay of urine catecholamines (CA) were performed in 30 patients and 21 normal persons. According to TCM, the patients were divided into two groups, 16 cases of deficiency-cold syndrome (DCD), and 14 cases of deficiency-heat syndrome (DHD). The results showed that in the patients with DCD, the activity of D beta H and the levels of CA were lower than those of the normal, whereas the activity of D beta H and the levels of CA of the patients with DHD were higher than those of the normal (P less than 0.01, P less than 0.05). Variations of the involved visceral organs determined in the traditional way made no difference to the above-mentioned changes. D beta H and CA correlated significantly to each other. The authors also took the canonical correlation analysis to the cases, the result showed that the heat syndrome correlated with D beta H and CA positively. These results showed hyperfunctioning of the sympathetic-adrenomedullary system in DHD and hypofunctioning of this system in DCD.

Clinical and experimental studies of coronary heart disease treated with yi-qi huo-xue injection.

The purpose of the present work was to evaluate the clinical efficacy and the mechanism of Yi-qi Huo-xue Injection (YHI) in treatment of coronary heart disease. YHI consists of Ginseng, Astragalus and Angelicae Sinensis. The 10% dextrose serves as a placebo. The results were as follows: 1. the frequency and severity of angina episodes were reduced by 90.63%; 2. the ischemic ST-T in ECG was improved in 56.25% of cases; 3. the tolerance to treadmill exercise was increased from 348.50 to 503.50 M.; 4. the left ventricular function was strengthened, PEP/LVET ratio reduced from 0.45 to 0.36, the activity of (Na(+)-K+) ATPase in myocardial cell membrane of rats inhibited by 19.2%; 5. the blood viscosity and erythrocyte electrophoretic time lowered; 6. the adhesion and aggregation of platelet in patients with CHD were inhibited by 27% and 59.4% respectively; 7. the plasma TXB2 level in CHD was reduced from 260.28 +/- 164.4 to 139.29 +/- 57.01 pg/ml; 8. the plasma 6-keto-PGF1 alpha level in CHD was increased from 33.45 +/- 22.5 to 57.48 +/- 13.1 pg/ml, and in rats from 185.77 to 366.33 pg/ml. The differences were all statistically significant (P less than 0.05-0.01) in comparison with the placebo group.

[Experimental chemotherapy of human gastric cancer cell lines in vitro and in nude mice].

Cytotoxic effects of allyl trisulfide (Alt, a synthetic chemical identical with one of the main active principles of garlic), 5 FU, MMC and DDP on SGC 7901 ( a moderately differentiated human gastric adenocarcinoma cell line) and MGC 803 (a poorly differentiated human gastric mucoadenocarcinoma cell line) had been reported before. In this paper, effects of repeated two doses of each drug and the combination of two drugs on these two cell lines were studied using relative clone-survival test. The inhibitory effects of Alt, MMC alone or combined on MGC tumor in nude mice were observed. No drug resistance was found when any one of the four agents at the same concentration were repeated twice separately at 60 hour interval in vitro. The cytotoxic effect of the repeated two doses was approximately equal to that of the single dose at double concentration. The in vitro test of combinations of two drugs showed that Alt plus MMC or 5 FU plus DDP had markedly synergistic effect on MGC cells; 5 FU plus DDP had markedly synergistic effect on SGC cells. The inhibition test on the growth of MGC tumor in nude mice indicated that the inhibition rates of Alt, MMC alone or combined were 58.3%, 86.3% and 84.3%. The systemic toxic effect of MMC alone was severe, whereas Alt alone or MMC plus Alt showed mild toxicity. For this reason, Alt plus MMC is recommended for clinical trials on poorly differentiated gastric cancer. In addition, for the comparison of in vitro test dose and clinical dose of each drug, the principle of clinical adult dose range (CADR) is proposed.