Biomedical subjects

Hui Yang

Publications and source records attributed to Hui Yang.

At least 91 records · Page 5Linked to original sources

PubMed2005

Composition and evolution of the V2r vomeronasal receptor gene repertoire in mice and rats.

Pheromones are chemicals produced and detected by conspecifics to elicit social/sexual physiological and behavioral responses, and they are perceived primarily by the vomeronasal organ (VNO) in terrestrial vertebrates. Two large superfamilies of G protein-coupled receptors, V1rs and V2rs, have been identified as pheromone receptors in vomeronasal sensory neurons. Based on a computational analysis of the mouse and rat genome sequences, we report the first global draft of the V2r gene repertoire, composed of approximately 200 genes and pseudogenes. Rodent V2rs are subject to rapid gene births/deaths and accelerated amino acid substitutions, likely reflecting the species-specific nature of pheromones. Vertebrate V2rs appear to have originated twice prior to the emergence of the VNO in ancestral tetrapods, explaining seemingly inconsistent observations among different V2rs. The identification of the entire V2r repertoire opens the door to genomic-level studies of the structure, function, and evolution of this diverse group of sensory receptors.

Amino Acid Sequence↗

PubMed2005

Bioactive benzophenones from Garcinia xanthochymus fruits.

A MeOH extract of Garcinia xanthochymus fruits was subjected to activity-guided fractionation, yielding two new benzophenones, guttiferone H (1) and gambogenone (2). Compound 1 contains a seven-membered ring attached to the bicyclo[3.3.1]nonane system at positions 7 and 8 and displayed cytotoxicity in the SW-480 colon cancer cell line (IC(50) = 12 microM). Compound 2 has a novel benzophenone bicyclo[3.3.2]decane system and displayed cytotoxicity in the SW-480 colon cancer cell line (IC(50) = 188 microM). Both 1 and 2 induced apoptosis in SW-480 colon cancer cells and displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC(50) = 64 and 38.7 microM, respectively). The structures of 1 and 2 were established by 1D and 2D NMR data analysis. Eleven known compounds, aristophenone A, alloathyriol, amentoflavone, 3,8' '-biapigenin, cycloxanthochymol, (+/-)-fukugetin, (+/-)-fukugiside, guttiferone E, isoxanthochymol, (+/-)-volkensiflavone, and xanthochymol, were also obtained. The 11 known compounds were also tested against SW-480 colon cancer cells and in the DPPH assay.

Antineoplastic Agents, Phytogenic↗

PubMed2005

Antioxidant and cytotoxic isoprenylated coumarins from Mammea americana.

Antioxidant-guided fractionation of Mammea americana L. seeds resulted in the identification of three new isoprenylated coumarins, mammea B/BA hydroxycyclo F (1), mammea E/BC (2), and mammea E/BD (3). In addition, twelve known isoprenylated coumarins, mammea A/AA (4), mammea A/AA cyclo D (5), mammea A/AA cyclo F (6), mammea A/AC cyclo D (7), mammea A/AD cyclo D (8), mammea B/BA (9), mammea B/BA cyclo F (10), mammea B/BB (11), mammea B/BC (12), mammea B/BD (13), mammea E/BA (14), and mammea E/BB (15), as well as two known flavanols, (+)-catechin (16) and (-)-epicatechin (17) were identified. The fifteen isoprenylated coumarins were screened for their cytotoxicity in the SW-480, HT-29, and HCT-116 human colon cancer cell lines and antioxidant capacities in the DPPH (1,1-diphenyl-2-picrylhydrazyl) free-radical assay. Compounds 1 - 15 exhibited significant cytotoxic activities in the SW-480, HT-29, and HCT-116 human colon cancer cell lines (IC50 ranges 13.9 - 88.1, 11.2 - 85.3, and 10.7 - 76.7 microM, in the three cell lines, respectively) at concentrations comparable to 5-fluorouracil (IC50 = 53.0, 46.1, and 45.1 microM), a drug frequently used for human colon cancer treatment. Compounds 2 - 4, 9, and 11 - 15 displayed high antioxidant activity in the DPPH assay (IC50 range 86 - 135 microM), compounds 1, 5 - 8, and 10, however, had no antioxidant activity (IC50 > 200 microg/mL) in the DPPH assay. The results of these assays were used to study the structure-activity relationships for this class of compounds. In the SW-480 cell line, the three new coumarins, 1 - 3, also exhibited dose-dependent increases in sub-diploid cells by flow cytometry, indicating that they induce apoptosis.

Antineoplastic Agents, Phytogenic↗

PubMed2005

The cross-species A3 adenosine-receptor antagonist MRS 1292 inhibits adenosine-triggered human nonpigmented ciliary epithelial cell fluid release and reduces mouse intraocular pressure.

PURPOSE: Antagonists to A3 adenosine receptors (ARs) lower mouse intraocular pressure (IOP), but extension to humans is limited by species variability. We tested whether the specific A3AR antagonist MRS 1292, designed to cross species, mimicks the effects of other A3AR antagonists on cultured human nonpigmented ciliary epithelial (NPE) cells and mouse IOP. METHODS: NPE cell volume was monitored by electronic cell sorting. Mouse IOP was measured with the Servo-Null Micropipette System. RESULTS: Adenosine triggered A3AR-mediated shrinkage of human NPE cells. Shrinkage was blocked by MRS 1292 (IC50 = 42 +/- 11 nM, p < 0.01) and by another A3AR antagonist effective in this system, MRS 1191. Topical application of the A3AR agonist IB-MECA increased mouse IOP. MRS 1292 reduced IOP by 4.0 +/- 0.8 mmHg at 25-microM droplet concentration (n = 10, p < 0.005). CONCLUSIONS: MRS 1292 inhibits A3AR-mediated shrinkage of human NPE cells and reduces mouse IOP, consistent with its putative action as a cross-species A3 antagonist.

Adenosine↗

PubMed2005

Budding yeast PDS5 plays an important role in meiosis and is required for sister chromatid cohesion.

Budding yeast PDS5 is an essential gene in mitosis and is required for chromosome condensation and sister chromatid cohesion. Here we report that PDS also is required in meiosis. Pds5p localizes on chromosomes at all stages during meiotic cycle, except anaphase I. PDS5 plays an important role at first meiotic prophase. Failure in function of PDS5 causes premature separation of chromosomes. The loading of Pds5p onto chromosome requires the function of REC8, but the association of Rec8p with chromosome is independent of PDS5. Mutant analysis and live cell imaging indicate that PDS5 play a role in meiosis II as well.

Anaphase↗

PubMed2005

Environmental toxins and alpha-synuclein in Parkinson's disease.

In recent years, environmental influences have been thought to play an important role in Parkinson's disease (PD). Evidence from epidemiological investigations suggests that environmental factors might take part in the disease process. Intriguingly, most of environmental toxins share the common mechanism of causing mitochondria dysfunction by inhibiting complex I and promoting alpha-synuclein aggregation, a key factor in PD. Therefore, understanding the mechanism of interactions between alpha-synuclein and environmental factors could lead to new therapeutic approaches to PD.

Animals↗

PubMed2005

Sintering and microstructure of silicon carbide ceramic with Y3Al5O12 added by sol-gel method.

Silicon carbide (SiC) ceramic with YAG (Y3Al5O12) additive added by sol-gel method was liquid-phase sintered at different sintering temperatures, and the sintering mechanism and microstructural characteristics of resulting silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and elemental distribution of surface (EDS). YAG (yttrium aluminum garnet) phase formed before the sintering and its uniform distribution in the SiC/YAG composite powder decreased the sintering temperature and improved the densification of SiC ceramic. The suitable sintering temperature was 1860 degrees C with the specimen sintered at this temperature having superior sintering and mechanical properties, smaller crystal size and fewer microstructure defects. Three characteristics of improved toughness of SiC ceramic with YAG added by sol-gel method were microstructural densification, main-crack deflection and crystal 'bridging'.

Aluminum Oxide↗

PubMed2005

[Cloning and expression of a novel gene restin and preparation of antisera against the recombinant restin].

AIM: To clone a new human gene, restin, from retinoic acid-treated promyelocytic cell line HL-60, express the protein in E.coli and prepare the antisera against the protein. METHODS: The restin gene was amplified from retinoic acid-treated promyelocytic cell line HL-60 by RT-PCR and cloned into a prokaryotic expression vector. The recombinant restin was induced to express in E. coli by temperature. After preliminary purification by SDS-PAGE, the restin protein was used to immunize rabbits to obtain antisera. The titers and specificity of the rabbit anti-restin antisera were tested by Western blot and immunofluorescence analysis. RESULTS: Recombinant restin with M(r) being about 26,000 was highly expressed in E. coli. The titers of the anti-sera to restin ranged from 1:100 to 1:800. Immunofluorescence analysis showed that restin distributed mainly in the nuclei of COS-7 cells. CONCLUSION: We successfully prepared the antisera against restin, which are useful for further investigation of biological functions of restin.

Animals↗

PubMed2005

[Determination of organochlorine pesticide residues in nine herbs by solid-phase extraction and capillary gas chromatography].

The solid-phase extraction and capillary gas chromatography was introduced for determining 13 organochlorine pesticide residues including alpha-benzene hexachloride (BHC), betaBHC, gamma-BHC, delta-BHC, p,p'-dichloro-diphenyl-dichloroethylene (pp'-DDE), p,p'-dichloro-di-phenyl-dichloroethane (pp'-DDD), o,p'-dichloro-diphenyl-trichloroethane (op'-DDT), pp'-DDT, heptachlor (HEPT), aldrin, heptachlor epoxide (HCE), dieldrin and endrin in Scutellaria baicalensis, Salvia miltiorrhiza, Belamcanda chinensis, Paeoniae lactiflora, Angelica dahurica, Arisaema erubescens, Fructus arctii, Anemarrhena asphodeloides and Platycodon grandiflorum. The organochlorine pesticides were extracted from herbs with mixed solvents of acetone and n-hexane by ultrasonic and cleaned up by Florisil solid-phase extraction column. Then, the extract was separated by capillary column (30 m x 0.25 mm i.d. x 0.25 microm) and detected by electrochemical detector. The carrier gas was N2 (99.999%) with the flow rate of 1.4 mL/min. The split ratio was 1:2.2. The injector temperature was 220 degrees C and the detector temperature was 330 degrees C. The column temperature was increased by the rate of 20 degrees C/min from 100 degrees C to 190 degrees C (hold for 1. 0 min), then to 235 degrees C by the rate of 4 degrees C/min and hold for 7 min at 235 degrees C. The good linearities were obtained for 13 organochlorine pesticides. The detection limits were between 0.064-0.61 microg/L. The average recoveries were between 87.3%-102.3% and relative standard deviations of 1.3%-6.8%. The method is effective, fast and accurate.

Capillary Electrochromatography↗

PubMed2005

[Surgical treatment of peripheral facial nerve paralysis: analysis of 51 cases].

OBJECTIVE: To investigate the surgical treatment of peripheral facial nerve paralysis as well as the factors which affect the operation effect. METHOD: Fifty-one cases of peripheral facial nerve paracusis were analyzed retrospectively. RESULT: Forty-two cases were followed up. Among them, twenty-two cases who received facial nerve decompression reached House I-II degree (22/36), 2 cases facial nerve anastomosis reached House I-II degree (2/4), and the function recovery of 2 cases who received facial nerve grafting > III degree both. CONCLUSION: Intensive and timely surgery is an efficient way in treating of peripheral facial nerve paralysis.

Adolescent↗

PubMed2005

[Study on interaction between CT-DNA and cytochrome C using UV-vis spectroscopy and electrochemistry].

The interaction between CT-DNA immobilized on the positively charged nylon membrane and cytochrome C was studied using UV-Vis reflectance absorption spectroscopy and electrochemistry. It was found that cytchrome C can be adsorbed on the negative charged CT-DNA surface with the active positive charge area. Therefore, CT-DNA can promote the direct electrochemical reaction of cytochrome C.

Adsorption↗

PubMed2005

[The relationship between 99mTc-MIBI scintimammography of breast cancer and multidrug-resistant proteins].

OBJECTIVE: To evaluate the relationship between the clearance rate of technetium-99m methoxyisobutylisonitrile ((99m)Tc-MIBI) in scintimammography and multidrug-resistant proteins expression in breast cancer tissues. METHODS: Seventy-six patients with breast cancer underwent (99m)Tc-MIBI scintimammography before treatment, and static planar images were taken at 10 min and 180 min after scintimammography. The clearance rate of (99m)Tc-MIBI was calculated in each patient. Immunohistochemical analysis was performed on pathological specimens of the 76 breast tumors to determine the expression of P-glycoprotein (P-gp), glutathione S-transferase Pi (GST-pi) and topoisomerase II (Topo II). RESULTS: The clearance rate was significantly higher in 36 patients with positive P-gp expression when compared with that in 40 patients with negative P-gp expression. There was no significant relationship between GST-pi, Topo II and the clearance rate of (99m)Tc-MIBI. CONCLUSION: The clearance rate of (99m)Tc-MIBI in breast imaging may be used to evaluate the P-gp level in breast cancers.

ATP Binding Cassette Transporter, Subfamily B↗

PubMed2005

[TNF-alpha gene expression of NAFLD rat intervened by the extracts of Rizoma Polygoni Cuspidati].

The real-time qPCR method had been used to detect and analyze the non-alcohol fatty liver disease (NEFLD) model in medical intervention in this research. The relative level of TNF-alpha mRNA in adipose tissue of intervention group was lower than that of control group. Their difference was significant (t = 2.452, P = 0.22). Compared with the control group, it decreased that the contents of liver trilyceride, total cholesterol, and glucose in intervention group. The difference of total cholesterol between two groups was significant (t = 2.555, P = 0.019). The extracts of Rizoma Polygoni Cuspidati could significantly decrease TNF-alpha mRNA level in adipose tissue, and it could decrease the contents of triglyceride, total cholesterol, and glucose in liver tissue. This Chinese traditional medicine can adjust the metabolism of liver adipose and glucose,and improve steatosis in liver cell.

Animals↗

PubMed2005

[Study on Bartonella species in rodents in western Yunnan, China].

OBJECTIVE: To study the infection status of Bartonella spp. in rodents in western part of Yunnan province. METHODS: Blood samples were collected from four species of rodents captured in four counties in western Yunnan in 2004. Bartomella was isolated through being cultured in brain and heart infusion agar media containing 5% rabbit blood. Suspective Bartomella strains isolates were confirmed by amplification of 379 bp of citrate synthase (gltA) gene with specific primer by polymerase chin reaction (PCR). RESULTS: Fifty-four strains of Bartomella isolates were obtained from 397 samples including four rodent species captured in the fields with an overall isolation-rate of 13.6% (54/397). The rates of isolation among different species were: 22.0% (22/100) in Rattus nitidus, 14.8% (31/210) in Rattus flavipectus and 1.2%(1/87) in Rattus norvegicus while in R. t. yunnanensis it was negative. CONCLUSION: These findings demonstrated that the local rodents in western Yunnan were widely infected by Bartomella spp. It is indispensable to study the vector and the route of transmission to discover the relations between Bartomella and human diseases.

Animals↗

PubMed2005

Detection of molecular weight of PMCA isoform with 20 cm SDS PAGE electrophoresis: compared with 8 cm SDS PAGE.

PURPOSE: To compare the effect of 20 cm SDS-PAGE electrophoresis, which is most widely used in proteomic research, in identifying human lens epithelium B3 (HLE B3) cells plasma membrane calcium ATPase (PMCA) isoform's apparent molecular weight (MW), with that of 8 cm SDS-PAGE electrophoresis. METHOD: HLE B-3 cells were cultured and membrane protein sample was collected. Part of the sample is electrophoresised with 20 cm gel, 16 mA/gel for 1.5 hrs and then 24 mA/gel for 4-5 hrs. The same sample is electrophoresised with 8cm mini gel, 200V for 2 hrs. Protein marker of known MW was run with the sample in the same gel. The resulting separated proteins were transferred to polyvinylidene difluoride (PVDF) membrane and Western blot were used to identify the PMCA isoform with specific antibody against PMCA 1, 2, 4. The apparent MW was calculated in reference to the known protein marker that was electrophoresised in the same gel. RESULT: In 8 cm gel the distance between 208 kDa and 126 kDa band was about 6.1 mm, while that of 20 cm gel was 32.8 mm. The distance between 126 kDa and 97 kDa was about 5.2 mm, while that of 20 cm gel was 20.2 mm. The migration distance differences of protein bands were significantly much longer in 20 cm gel than in 8 cm gel (P < 0.005). But the bands were generally more condensed in 8 cm gel. The apparent MW of PMCA1, 2, 4 were 153.8, 153.5 and 152.9 kDa respectively. In the 20 cm gel, the apparent MW for PMCA1, 2, 4 was 153.1, 125.5 and 147.4 kDa respectively. CONCLUSION: Both the 20 cm gel and 8 cm gel successful identified PMCA 1, 2, 4 in HLE B-3 cells. The apparent MW for PMCA1, 2, 4 was 153.8, 153.5 and 152.9 kDa respectively in 8 cm gel, and 153.1,125.5 and 147.4 kDa respectively in 20 cm gel. PMCA2 probably had some kinds of degradation during the long electrophoresis time in 20 cm gel.

Blotting, Western↗

PubMed2004

Pancreatic carcinoma cells express neuropilins and vascular endothelial growth factor, but not vascular endothelial growth factor receptors.

BACKGROUND: Neuropilins (NRPs) are characterized as coreceptors of vascular endothelial growth factor (VEGF). In the current study, the authors assessed the expression of NRPs, VEGF, and vascular endothelial growth factor receptors (VEGFRs), as well as VEGF-induced cell proliferation, in pancreatic carcinoma cell lines and tissue specimens. METHODS: Human pancreatic carcinoma cell lines (Panc-1 and MIA PaCa-2), normal human pancreatic ductal epithelial cells (HPDE), and human umbilical vein endothelial cells (HUVECs) were cultured. Human pancreatic adenocarcinoma tissue specimens were also studied. Expression levels of NRPs, VEGFRs, and VEGF were determined by real-time polymerase chain reaction analysis and immunostaining. Cell proliferation was examined using a [3H]thymidine incorporation assay. RESULTS: Both NRP-1 and NRP-2 were expressed in Panc-1 cells, HPDE cells, and HUVECs but were expressed minimally in MIA PaCa-2 cells. Panc-1 expressed 30 times more NRP-1 mRNA than NRP-2 mRNA. NRP-1 levels in Panc-1 cells were 5.3 times higher than in HPDE cells but were similar to NRP-1 levels in HUVECs. NRP-2 levels in Panc-1 cells were similar to NRP-2 levels in HPDE cells but lower than NRP-2 levels in HUVECs. Expression of all three VEGFRs was observed only in HUVECs. However, VEGF mRNA was detected in all cell types except for HUVECs. NRP-1 immunoreactivity levels were much higher than NRP-2 immunoreactivity levels in Panc-1 and human pancreatic adenocarcinoma tissue specimens, whereas VEGFRs were not detected in either of these two settings. In response to VEGF165, [3H]thymidine incorporation in Panc-1 cells increased significantly (by 61%; P < 0.01). A monoclonal antibody against human NRP-1 significantly blocked VEGF-induced cell proliferation in Panc-1 cells. CONCLUSIONS: The pancreatic carcinoma cell line Panc-1 and adenocarcinoma tissue specimens expressed high levels of NRP-1 and VEGF, but not VEGFRs, and exogenous VEGF significantly increased NRP-1-mediated, but not VEGFR-mediated, Panc-1 cell proliferation. These data suggested that NRP-1 may be involved in the pathogenesis of pancreatic carcinoma.

Adenocarcinoma↗

PubMed2004

Long-term restoration of nigrostriatal system function by implanting GDNF genetically modified fibroblasts in a rat model of Parkinson's disease.

The motor behavior and levels of dopamine and its metabolites in the striatum were studied in rats that received a unilateral injection of 6-OHDA and underwent grafting of rat-derived primary fibroblasts that had been genetically modified to express lacZ and human glial cell line-derived neurotrophic factor (GDNF). Rotation behavior tests were performed each week and striatal levels of DA and its metabolites were measured every 4 weeks after grafting of fibroblasts that expressed lacZ, with or without additional transfection of the GDNF transgene. Rats grafted with GDNF-producing fibroblasts showed a significant improvement in motor behavior as determined by the rotation test, with a less pronounced reduction in the levels of dopamine and its metabolites in the striatum as compared with those in the control animals or brain parts. In addition, there was a lower decrease in the number of TH immunoreactive neurons in the substantia nigra ipsilateral to the lesion in rats with GDNF-producing fibroblasts than in rats with lacZ-expressing fibroblasts. These results support the notion that intracerebral grafting of fibroblasts that express GDNF is a potentially useful therapeutic strategy for treating Parkinson's disease.

Animals↗

PubMed2004

Analysis of polyphenolic antioxidants from the fruits of three pouteria species by selected ion monitoring liquid chromatography-mass spectrometry.

Pouteria campechiana, Pouteria sapota, and Pouteria viridis are tropical plants in the Sapotaceae family that bear edible fruits. The fresh fruits of these three Pouteria species were each extracted, and activity-guided fractionations were performed to identify the antioxidant constituents. Seven polyphenolic antioxidants, gallic acid (1), (+)-gallocatechin (2), (+)-catechin (3), (-)-epicatechin (4), dihydromyricetin (5), (+)-catechin-3-O-gallate (6), and myricitrin (7), were isolated and identified. Extracts of the three Pouteria fruits were analyzed by a selected ion monitoring liquid chromatography-mass spectrometry method to quantify their polyphenolic antioxidants. The highest level of the seven measured polyphenols was found in P. sapota, the second highest in P. viridis, and the lowest in P. campechiana. The levels of the seven polyphenols corresponded with the results of the 1,1-diphenyl-2-picrylhydrazyl assay, by which P. sapota had the highest antioxidant activity, P. viridis the second highest, and P. campechiana the lowest.

Antioxidants↗