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Li Yang

Publications and source records attributed to Li Yang.

At least 91 records · Page 5Linked to original sources
PubMed2006

[Liver targeting of cationic liposomes modified with soybean-derived sterylglucoside in vitro].

AIM: To construct a liposomal liver targeting delivery system by adding soybean-derived sterylglucoside (SG) to the cationic liposomes. METHODS: The physico-chemical properties of SG modified cationic lipsomes were investigated using fluorescein sodium (FS) as a model drug, as well as the interaction of SG modified liposomes with HepG2 2. 2. 15 cells in the point of involvement of asialoglycoprotein receptor (ASGP-R) mediated transfection. Liver targeting of modified cationic liposomes were also investigated using liver perfusing technique, and hepatocytes and non-hepatocytes were separated and examined after perfusing. RESULTS: All the formula yielded high incorporation efficiency (83.12% - 91.74%), small particle size (93.0 - 124.4 nm). The zeta potential of blank liposomes all showed positive values. The transfection efficiency of FS entrapped in SG-liposomes with HepG2 2.2. 15 was significantly higher than that of liposomes without modification. The transfection of SG-liposomes were reduced significantly by the 20/30 mmol galactose as a competitor of ASGP-R. All the cationic liposomes showed high level of liver uptake of FS. Compared with the uptake of non-hepatocytes of each respectively, only SG/Brij-35 liposomes showed difference in FS uptake by hepatocytes (P < 0.05). CONCLUSION: It showed that SG/Brij-35 modified cationic liposomes are potentially useful drug carrier to liver but may be affected by different modification.

Animals↗
PubMed2006

[Experimental study of anti-cancer effect of Mannan-modified targeted nanoliposome on mice].

OBJECTIVE: To test the anti-cancer effect of mannan-modified targeted nanoliposome on mice. METHODS: The 3beta[N-(N',N'-dimethylaminoethane) -carbamoyl] cholesterol (DC-chol) was synthesized by the chemical reaction of cholesteryl chloroformate and N, N-dimethylethylendiamine. The DC-chol was then mixed with dioleoylphosphatidylethanolamine (DOPE) and chol-AECM-mannan to produce the sonicated mannan-modified targeted nanoliposome. The size of the nanoliposome was measured by zetasizer. Nanoliposome or purified EGFR (as control) was injected to the C57 mice with implanted lung cancers intravenously. The growth of tumors was observed, followed by ELISA and Western tests of serum antibodies. RESULTS: The liposome nanoparticle had a size of 132 nm. The experimental groups had significant higher levels of blood serum antibodies than the controls. The experimental groups also had less volumes of tumors than the controls (P<0.05). CONCLUSION: The growth of tumor has been inhibited by mannan-modified targeted nanoliposome. The mannan-modified targeted nanoliposome has anti-cancer effect on mice.

Animals↗
PubMed2006

[Research on Rho-kinase expression in pulmonary arterioles of rat exposed to hypoxia].

OBJECTIVE: To evaluate the expression and the role of Rho-kinase (ROCK I and ROCK II )in the development of hypoxic pulmonary hypertension of rat. METHODS: Thirty six of adult male SD rats were randomly divided into six groups; one group was exposed to air as normal control, the other five groups were exposed to isobaric hypoxia for 1 day, 3 days, 1 week, 2 weeks and 3 weeks respectively. Microtube method was used to measure the mean pulmonary arterial pressure (mPAP). The right ventricle (RV) and left ventricle plus atrial ventricular septum (LV+S) were isolated and weighed to calculate the value of RV/(LV+S). The amounts of Rho-kinase and Rho-kinase mRNA in rat pulmonary artery were determined by immunohistochemistry, in situ hybridization and image analysis. RESULTS: The mPAP and RV/(LV+S) values increased with time prolongation of rats exposed to hypoxia (P<0.05). The ratio of arteriole wall thickness/vascular external diameter(WT%) and vascular area/total vascular area(WA%) went forward to a height with exposing rats to hypoxia for a long time; WT% and WA% of hypoxia group rats exposed for 3 weeks were significantly higher than that of control group (P<0.05). All of ROCK I , ROCK II, ROCK I mRNA and ROCK II mRNA in pulmonary arterioles got the enhanced positive signals of immunohistochemistry staining or in situ hybridization with prolonging the time of rats exposed to hypoxia. The hypoxia group for 3 weeks got significantly stronger staining signals of Rho-kinase and Rho-kinase mRNA in pulmonary arterioles than that of control group (P<0.05). The positive staining of ROCK I , ROCK I mRNA, ROCK II or ROCK II mRNA in pulmonary arterioles all positively related with mPAP, WA% and WT% (r=0.404, 0.267 and 0.263; 0.500, 0.263 and 0.260; 0.490, 0.295 and 0.286; 0.579, 0.251 and 0.254) (P<0.05). CONCLUSIONS: Hypoxia led Rho-kinase and Rho-kinase mRNA to have an increased expression. Rho-kinase may play a role in the development of hypoxic pulmonary hypertension by contracting and remodeling pulmonary arterioles.

Animals↗
PubMed2006

[Effect of beta-lactam antibiotics in drug-induced hemolysis].

The study was purposed to evaluate synergistic effect of beta-lactam antibiotics in drug-induced hemolysis. The general information, including primary diseases, therapeutic drugs, infection pathogens in 6 patients with pulmonary infection and unknown reason anemia were integrated and analyzed. The leukocyte and reticulocyte counts, total bilirubin (TB), direct bilirubin (DB), fasting blood glucose (Glu in peripheral blood) were all determined by conventional method. At the same time, the erythrocyte direct antiglobulin test (DAT), complement fixation test (CFT), cell culture and smear examination were carried out. The antibodies in plasma were also detected by indirect antiglobulin test (IAT). The result showed that levels of WBC, TB, DB, Glu and reticulocyte in six patients treated with beta-lactam antibiotics were raised remarkably. DAT was strongly positive, but no RBC antibodies were detected in the plasma by IAT. The binding of red cells by monocytes or lymphocytes was great, and the hemolysis of red cells by alexin not appeared. After stopping above-mentioned beta-lactam antibiotic administration, patient's WBC, TB, DB, and Glu levels returned to normal values. Furthermore, DAT test result turned to negative. It is concluded that beta-lactam antibiotics lead to drug-induced hemolysis by non-specific adsorption of some proteins onto RBC surface, and their proteins may be considered as direct cause for this hemolysis.

Aged↗
PubMed2006

[Effect of perfusion CT scan on hepatic hemodynamic changes in rats with liver micrometastases].

BACKGROUND & OBJECTIVE: Hepatic metastases are common for patients with malignant tumors, especially for the gastrointestinal malignancies. Early diagnosis confers better prognosis. This study was designed to investigate the hepatic hemodynamic changes by multi-slice helical perfusion CT in rats with liver micrometastatases of Walker-256 tumor cells. METHODS: Liver micrometastatases were produced in 22 SD rats by injecting 2 x 10(7) Walker-256 cells into the spleens. The ten experimental control rats were injected with normal saline solution. Ten rats were randomized into empty self control group from the experimental group before injecting tumor cells, which were studied by CT perfusion technique before being injected tumor cells. The time-density curves of the aorta, portal vein, and liver were used to calculate liver perfusion parameters by gradient method designed for the dual blood supply. These liver perfusion parameters were hepatic arterial perfusion (HAP), portal vein perfusion (PVP), hepatic perfusion index (HPI) and total hepatic blood flow. All the parameters were compared between the groups. H&E staining method was used to confirm the micrometastases pathologically. RESULTS: In the experimental group, 19 rats were found with micrometastases, of which the diameter was 0.5 mm to 6.6 mm. HAP was (97.67+/-31.42) ml x min(-1) x (100 ml) (-1) in metastasis group, and (43.35+/-17.39)ml x min(-1) x (100 ml) (-1) in control group, and (40.77+/-18.91) ml x min(-1) x (100 ml) (-1) in empty self control group. PVP was (295.49+/-61.85) ml x min(-1) x (100 ml) (-1) in metastasis group, and (385.7+/-71.25) ml x min(-1) x (100 ml) (-1) in control group, and (362.73+/-78.56) ml x min(-1) x (100 ml) (-1) in empty self control group, It was found that the HAP was higher in the rats with micrometastases than in those of the empty control group and also those of control group (F=47.84, P<0.000,1). While the PVP was lower in the rats with micrometastases than in those of the two control groups (F=14.10, P<0.000,1). For the total hepatic blood flow, no significant difference was found among the three groups (F=1.39, P=0.255). CONCLUSION: Higher HAP and lower PVP was noted in the rats with micrometastases. Perfusion CT technique can be used to evaluate the hepatic hemodynamic changes and thus has a potential clinical value for early diagnosis of liver micrometastases.

Animals↗
PubMed2006

[Study on spray-drier preparation technology of weitai granules using orthogonal experiments].

OBJECTIVE: To screen preparation technique in order to raise the end-product and economical efficiency of spray-drier preparation technology of weitai granules. METHODS: Newly Fluid-bed-spray-drier-granulation technique was adoped and taken extracting technique, temperature of exit and entry and the matching of accessories as inspecting factors, two levels of each factors, end-product and the water content of semi-finished weitai granules as inspecting marker, the best preparation technique of weitai granules was screened by orthogonal desing. RESULTS: Among the 3 factors, the matching of accessories was most notalbe (P < 0.01), next was the temperature of exit and entry (P < 0.05). However, the extracting technique was of little importance (P > 0.05). CONCLUSION: The optimum spray-drier granulation technique of weitai granules is A3B1C3.

Adhesives↗
PubMed2006

[Analysis of paralytic shellfish poisoning and diarrhetic shellfish poisoning of bivalves in seafood market of Guangzhou].

OBJECTIVE: Paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) in 7 species of economical shellfishes were analyzed for 1 year, which collected from Huangsha seafood market of Guangzhou from Apr, 2004 to Mar, 2005. METHODS: The levels of PSP and DSP in bivalves were determined with mouse bioassay of AOAC. The risk assessment of PSP and DSP in bivalves was conducted according to FAO and Chinese Administration Organization of Fish Culture and Seaport. RESULTS: PSP was detected in 2 species of the shellfishes assayed and DSP was found out in 6 species. The content of PSP was lower than 4MU/g tissue, whereas the level of PSP in glands was higher than in muscles. DSP toxin was detected in 36 samples of 6 species, what is more, DSP level in 10 samples exceeded the safety threshold. The levels in PSP and DSP of bivalves were all higher in spring and winter with some characteristic of season. CONCLUSION: The results suggested that PSP in economical shellfish in Guangzhou market was lower, and shellfish was safe to eat in term of the PSP level if glands were discarded, but DSP contamination in bivalves was severe. It is essential to detect and assess the risk of DSP and PSP in bivalves from seafood market in the future.

Animals↗
PubMed2006

[Effect of lenti-mCCL20 on the growth of mouse tumor].

OBJECTS: We aim at inducing a potent antitumor immune response via CCL20 expressing in situ tumor. METHODS: We constructed a recombinant lentivirus encoding mouse CCL20 cDNA and transduced the mouse mesenchymal stem cells (mMSCs) in vitro, and then selected the transfected cells to get a stable mixed mCCL20-expressing pool (named as lenti-mCCL20-mMSCs) with blasticidin. By the same means, we produced another pool named as lenti-null-mMSCs. The CT26 was mixed with lenti-mCCL20-mMSC and inoculated sc into the left hinder back of BALB/c mouse. And also the CT26 was alone, or mixed with lenti-null-mMSCs or parent mMSCs, and then inoculated sc into BALB/c mice serving as controls. RESULTS: We got a lenti-mCCL20-mMSCs expression construct. It was shown that mCCL20 increased intratumoral lymphocytes infiltration and facilitated tumor growth in syngeneic murine tumor model. CONCLUSIONS: CCL20 expressing in situ tumor enhances intratumoral lymphocytes infiltration but facilitates tumor growth. However, the mechanism involved remains to be further elucidated.

Animals↗
PubMed2005

Simultaneous determination of phenols (bibenzyl, phenanthrene, and fluorenone) in Dendrobium species by high-performance liquid chromatography with diode array detection.

A new method of analysis of 11 phenols, including five bibenzyls, three phenanthrenes, and three fluorenones, using high-performance liquid chromatography (HPLC)-diode array detection (DAD) was described. The separation of 11 phenols was effected by RP-HPLC (Beckman Coulter ODS column, 5 microm, 250 mm x 4.6 mm) using linear gradient elution systems of acetonitrile-1/1000 trifluoroacetic acid (TFA). Satisfactory separation of these compounds was obtained in less than 45 min. The method was validated for linearity, repeatability, limits of detection (LOD) and limits of quantification (LOQ). Good results were obtained with respect to repeatability (relative standard deviation (RSD)<3.5%) and recovery (85.77-104.92%). The developed method was applied to the simultaneous determination of 11 phenols from totally 31 Dendrobium species (mainly of medicinal plants) as well as other four samples from the similar genera as Pholidota, Flickingeria and Bulbophyllum. The range of the total amounts of bibenzyl, phenanthrene and fluorenone were found to from trace: 4.00, not detected (nd): 0.42 and nd: 0.24 microg mg(-1), respectively.

Calibration↗
PubMed2005

Leber's hereditary optic neuropathy is associated with the mitochondrial ND4 G11696A mutation in five Chinese families.

We report here the clinical, genetic, and molecular characterization of five Chinese families with Leber's hereditary optic neuropathy (LHON). Clinical and genetic evaluations revealed the variable severity and age-of-onset in visual impairment in these families. Strikingly, there were extremely low penetrances of visual impairment in these Chinese families. Sequence analysis of the complete mitochondrial genomes in these pedigrees showed the distinct sets of mtDNA polymorphism, in addition to the identical ND4 G11696A mutation associated with LHON. Indeed, this mutation is present in homoplasmy only in the maternal lineage of those pedigrees but not other members of these families. In fact, the occurrence of the G11696A mutation in these several genetically unrelated subjects affected by visual impairment strongly indicates that this mutation is involved in the pathogenesis of visual impairment. Furthermore, the N405D in the ND5 and G5820A in the tRNA(Cys), showing high evolutional conservation, may contribute to the phenotypic expression of G11696A mutation in the WZ10 pedigree. However, there was the absence of functionally significant mtDNA mutations in other four Chinese pedigrees carrying the G11696A mutation. Therefore, nuclear modifier gene(s) or environmental factor(s) may play a role in the phenotypic expression of the LHON-associated G11696A mutation in these Chinese pedigrees.

Adolescent↗
PubMed2005

Endotoxin-induced hypoxic-ischemic tolerance is mediated by up-regulation of corticosterone in neonatal rat.

Previous studies suggest that the endotoxin lipopolysaccharide (LPS) may have dual effects on brain damage induced by hypoxia-ischemia (HI) in 7-d-old rats, depending on the exposure paradigm. Although a 4-h interval between LPS administration and HI results in sensitization to HI brain injury, tolerance is observed when LPS is administered 24 h before HI. Our hypothesis is that endogenous corticosteroids are important in acquiring tolerance to HI. Neonatal rats received a single injection of LPS (1.0 mg/kg) either 4 h or 24 h before HI, or two LPS injections (4 h and 24 h) before HI. Increased brain injury was seen in animals subjected to a single LPS injection made 4 h before HI. In contrast, both the single 24-h exposure and the double injections of LPS resulted in tolerance to HI brain damage. To study the effects of corticosteroids on HI tolerance, RU486, a glucocorticoid receptor blocker, was subcutaneously injected at the same time as LPS (1.0 mg/kg), 24 h before HI stress. RU486-LPS treatment counteracted the LPS-induced tolerance effect, and aggravated the HI-induced brain injury compared with the vehicle-LPS-treated group. RU486 did not aggravate the HI-induced brain injury produced 24 h later in saline-injected animals. LPS (1.0 mg/kg) injected into 6-d-old rats transiently up-regulated serum corticosterone levels (119.6, 57.9, 56.8, and 28.3 ng/mL at 6, 12, 24, and 48 h after the LPS injection, respectively). We conclude that endotoxin-induced up-regulation of endogenous corticosterone appears to be critical for acquiring endotoxin-induced HI tolerance.

Animals↗
PubMed2005

Protective effects of flavonols and their glycosides against free radical-induced oxidative hemolysis of red blood cells.

The in vitro oxidative hemolysis of human red blood cells (RBCs) was used as a model to study the free radical-induced damage of biological membranes and the protective effect of flavonols and their glycosides (FOHs), i.e., myricetin (MY), quercetin (Q), morin (MO), kaempferol (K), rutin (R), quercetin galactopyranoside (QG), quercetin rhamnopyranoside (QR), and kaempferol glucopyranoside (KG). The hemolysis of RBCs was induced by a water-soluble free radical initiator 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). It was found that addition of AAPH at 37 degrees C to the suspension of RBCs caused fast hemolysis after a short period of inhibition period, and addition of FOHs significantly suppressed the hemolysis. The FOHs (MY, Q, R, QG and QR) which bears an ortho-dihydroxyl functionality showed much more effective anti-hemolysis activity than that of the other FOHs (MO, K and KG) bearing no such functionality.

Amidines↗
PubMed2005

CD73 and Ly-6A/E distinguish in vivo primed but uncommitted mouse CD4 T cells from type 1 or type 2 effector cells.

Primed CD4 T cells may develop into effector T cells such as Th1 and Th2, or remain uncommitted as Th primed precursor (Thpp) cells that can subsequently differentiate into Th1 and Th2 cells. Although mouse Thpp-like cells have also been identified among spleen and particularly lymph node cells, further characterization of these cells has been difficult without a defining cell surface marker. Using Affymetrix GeneChips followed by FACS analysis, we found that in vitro-derived Thpp cells expressed CD73 but not Ly-6A/E, whereas Th1 and Th2 cells showed the reciprocal pattern. CD73+ Ly6A/E- memory CD4 T cells were identified in normal C57BL/6 mice, and the proportion of these cells was highest in lymph nodes, lower in spleens, and lowest in the lungs. These cells produced IL-2 and MIP-1alpha, but much less IL-4 and IFN-gamma than CD73- Ly6A/E+ cells. Similar results were obtained with additional Ly-6.2 mouse strains, but not Ly-6.1 strains. Restimulation of Thpp-like CD73+ Ly-6A/E- cells in Th1- or Th2-polarizing conditions induced differentiation into populations producing mainly IFN-gamma or mainly IL-4, respectively. In contrast, the effector-like CD73- Ly-6A/E+ population was more committed, and continued to produce both IL-4 and IFN-gamma in both conditions. CD73 and Ly-6A/E expression therefore identify a population of Thpp-like cells in C57BL/6 mice and at least some other Ly-6.2 mice.

5'-Nucleotidase↗
PubMed2005

Curcumin and its analogues as potent inhibitors of low density lipoprotein oxidation: H-atom abstraction from the phenolic groups and possible involvement of the 4-hydroxy-3-methoxyphenyl groups.

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, 1) is a yellow ingredient isolated from turmeric (Curcumin longa). It has been shown to exhibit a variety of biological activities including antioxidative activity. In order to find more active antioxidants with 1 as the lead compound we synthesized curcumin analogues, i.e., 1,7-bis(3,4-dihydroxyphenyl)-1,6-heptadiene-3,5-dione (2), 1-(3,4-dihydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (3), 1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (4), 1,7-bis (4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (5), 1-(3,4-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (6), 1,7-bis(3,4-dimethoxyphenyl)-1,6- heptadiene-3,5-dione (7), 1,7-bis(4-methoxyphenyl)-1,6-heptadiene-3,5-dione (8), and 1,7-diphenyl-1,6-heptadiene-3,5-dione (9). Antioxidative effects of curcumin and its analogues against free radical initiated peroxidation of human low density lipoprotein (LDL) were studied. The peroxidation was initiated either by a water-soluble initiator 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), or by cupric ion (Cu2+). The reaction kinetics were monitored either by the uptake of oxygen and the depletion of alpha-tocopherol present in the native LDL, or by the formation of thiobarbituric acid reactive substances. Kinetic analysis of the antioxidation process demonstrates that these compounds, except 7, 8, and 9, are effective antioxidants against AAPH- and Cu2+ -initiated LDL peroxidation by H-atom abstraction from the phenolic groups. Compounds 2 and 3 which bear ortho-diphenoxyl functionality possess significantly higher antioxidant activity than curcumin and other analogues, and the 4-hydroxy-3-methoxyphenyl group also play an important role in the antioxidative activity.

Antioxidants↗
PubMed2005

Monolayer-protected gold nanoparticle coalescence induced by photogenerated radicals.

Acyl and alkyl radicals generated photochemically in a solution containing monolayer-protected gold nanoparticles are shown to efficiently liberate the alkylthiolate ligands into the solution as the thioacetyl or alkyl sulfide, respectively. This radical-induced reaction initiates a coalescence of the gold cores to facilitate an increase in core size. The photoinitiated radical reaction also liberates monolayers from two-dimensional gold surfaces.

Journal Article↗
PubMed2005

Inhibition of lipid peroxidation and protein oxidation in rat liver mitochondria by curcumin and its analogues.

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, 1) is a yellow ingredient isolated from turmeric (curcumin longa). It has been shown to exhibit a variety of biological activities including antioxidative activity. In order to find more active antioxidants with 1 as the lead compound we synthesized curcumin analogues, i.e., 1-(3,4-dihydroxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (2), 1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (3), 1,7-bis-(4-hydroxyphenyl)-1,6-heptadiene-3,5-dione (4), 1-(3,4-dimethoxyphenyl)-7-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (5), 1,7-bis(3,4-dimethoxyphenyl)-1,6-heptadiene-3,5-dione (6), and 1,7-diphenyl-1,6-heptadiene-3,5-dione (7), and evaluated their antioxidative activity. The in vitro oxidative damage to both lipids and proteins in rat liver mitochondria was used as a model to study the free radical-induced oxidative damage of biological lipids as well as proteins and the protective effects of these curcumin analogues. It was found that these compounds, except 6 and 7, could effectively inhibit the free radical induced lipid peroxidation and protein oxidative damage of rat liver mitochondria by H-atom abstraction from the phenolic groups. Compound 2 which bear ortho-diphenoxyl functionality exhibited remarkably higher antioxidative activity for lipids and proteins than curcumin and other analogues, and the 4-hydroxy-3-methoxyphenyl group also play an important role in the antioxidative activity.

Animals↗