Biomedical subjects

Yang Wang

Publications and source records attributed to Yang Wang.

At least 91 records · Page 5Linked to original sources

PubMed2006

[Microscopic study on skin and soft tissue after repeated expansion].

OBJECTIVE: The study was to evaluate the microscopic changes on skin and soft tissue after repeated expansion for clinical work. METHODS: Six little pigs were divideded as: conventional expansion group, repeated expansion group, and blank control group. Histologic, ultrastructure and bFGF of the skin were observed and measured in each group after samples had been made. RESULTS: The skin and soft tissue after repeated expansion were healthy on the whole. Compared with the conventional expansion group, there was more microscopic change in the repeated expansion group. Collagen fibers were injured evidently. Cells were injured slightly and proliferated much more, and moreover, they were more activated. The content of bFGF was more higher. CONCLUSIONS: The skin and soft tissue after repeated expansion are healthy on the whole by more growth and more repair though repeated expansion may result in more injuries. So repeated expansion is safe and feasible.

Animals↗

PubMed2006

[Application of near-field Raman spectroscopy to nano-structure characterization].

Near-field Raman spectroscopy is a novel technology in the near-field optics, and attracts much attention of scientists because of the realization of spectral characterization of nano-structure. The technical advantage of Raman spectroscopy is described in the present review. The principle and practical technical scheme of near-field Raman spectroscopy systems are introduced. Several applications of near-field Raman spectroscopy are mentioned in detail, including carbon nanotube characterization, biological specimen imaging, thermoelectric crystal characterization, dye single molecule detection etc., revealing a broad prospect of the development of near-field Raman spectroscopy in various scientific research fields.

English Abstract↗

PubMed2006

[Research advances of macroporous resin].

We surveyed the literatures domestic and abroad, and summarized the physical and chemical characterizations as well as preparation and applications of macroporous resin. The research of physical parameter and chemical parameter includes the measurement of the organic residue, the application research includes the separation and purification methods of the phytochemical ingredients. Macroporous resin show its advantages in the field of phytochemical studies, traditional Chinese medicine development and production, but there exist some disadvantages in its performance and application. It's necessary to establish the quality standard and the technical specifications to promote the standardization of the research and the application of the macroporous resin.

Resins, Synthetic↗

PubMed2006

[The effects of matrine on cell proliferation and telomerase activity in retinoblastoma cells in vitro].

OBJECTIVE: To evaluate the effects of matrine on cell proliferation and telomerase activity in retinoblastoma cells in vitro. METHODS: HXO-Rb44 cells were treated with 0.1 to 3.2 mmol/L matrine for 24 h, then cell viability was measured by MTT assay. Apoptosis rates were evaluated by flow cytometry and TUNEL assay after the cells were treated for various durations. The telomerase activity were measured by telomeric repeat amplification protocol. RESULTS: MA inhibited the growth of HXO-Rb44 cells. Ma induced the apoptosis and down-regulated the telomerase activity of HXO-Rb44 cells, which were time dependent. There was a positive correlation between the telomerase activity and the apoptosis (r = -0.961, P < 0.01). CONCLUSIONS: Ma can induce the apoptosis and down-regulate the telomerase activity of retinoblastoma cells, which may be one of important mechanisms to inhibit the cell proliferation. It suggests that Ma may be a potent drug for the treatment of retinoblastoma.

Alkaloids↗

PubMed2006

[Effects of multi-glycoside of Tripterygium wilfordii Hook. f. on proteinuria and expression of slit diaphragm-associated molecules in rats with anti-thy1.1 glomerulonephritis].

OBJECTIVE: To examine the effect of multi-glycoside of Tripterygium wilfordii Hook. f. (GTW) on proteinuria and expression of slit diaphragm-associated molecules such as nephrin and podocin in glomerulonephritis induced by anti-Thy1.1 antibody (anti-Thy1 . 1 GN). METHODS: Anti-Thy1.1 GN was induced in rats by a single intravenous injection with 500 microg of anti-Thy1.1 mAb 1-22-3. Fourteen rats were randomly divided into 2 groups, the GTW-treated group and vehicle treated group, and sacrificed on day 14 in Experiment 1 or on day 7 in Experiment 2 after induction of Anti-Thy1.1 GN. Daily oral administration of GTW and vehicle as a control was started from 3 days before injection or at the same time of injection to the day of sacrifice in Experiment 1 or 2. Proteinuria was determined during 14 days in Experiment 1 or during 7 days in Experiment 2. From kidneys taken at sacrifice, glomerular morphological changes, glomerular macrophage infiltration, glomerular expression of nephrin and podocin, and its mRNA expression in renal tissue were examined. RESULTS: In Experiment 1, proteinuria and mesangial matrix expansion were significantly attenuated by GTW treatment. No difference in staining intensity of nephrin and podocin in glomeruli was observed between GTW treated group and vehicle treated group on day 14. In Experiment 2, GTW treatment significantly ameliorated proteinuria, mesangial injury and activated macrophage infiltration in glomerulus. In addition, it significantly increased the expression of nephrin and podocin and its mRNA expression in glomeruli on day 7. CONCLUSION: In anti-Thy1.1 GN, the reduced expression of nephrin and podocin may contribute to the development of mesangial injury and proteinuria. The findings suggest that GTW ameliorates not only proteinuria but also mesangial lesions in anti-Thy1 . 1 GN most likely by increasing the expression of nephrin and podocin.

Animals↗

PubMed2005

Catalytic micropumps: microscopic convective fluid flow and pattern formation.

As innovations continue to be made in the fields of microfluidics and the colloidal assembly, new strategies for moving particles and fluids may be needed. Heterogeneous catalysis provides means of locally converting the stored chemical energy of fuels to mechanical energy. We report an ambient temperature stationary "pump" that generates a proton concentration gradient through the bipolar electrochemical decomposition of hydrogen peroxide on patterned silver-gold surfaces. The resulting electric field drives convective fluid flow and pattern formation of colloidal tracer particles at the microscopic level by a combination of electroosmotic and electrophoretic forces.

Journal Article↗

PubMed2005

An expansion of the dual clip-domain serine proteinase family in Manduca sexta: gene organization, expression, and evolution of prophenoloxidase-activating proteinase-2, hemolymph proteinase 12, and other related proteinases.

Prophenoloxidase-activating proteinases (PAPs) take part in insect defense responses including melanotic encapsulation and wound healing. To understand their gene structure and regulation, we screened a genomic library and isolated overlapping lambda clones for Manduca sexta PAP-2, hemolymph proteinase 12 (HP12), and HP24. Complete nucleotide sequence analysis indicated that all three genes encode polypeptides with two regulatory clip domains at the amino terminus, a linker region, and a catalytic serine proteinase domain at the carboxyl terminus. Each gene contains eight exons, with introns located at equivalent positions. Similar sequences are present in introns as well as exons, indicating that these genes arose from recent gene duplication and sequence divergence. We analyzed their 5' flanking sequences and identified putative immune and hormone responsive elements. Reverse transcription-polymerase chain reactions confirmed that PAP-2 and HP12 mRNA levels in the larval fat body and hemocytes increased after a bacterial challenge. However, HP24 expression was barely detected. PAP-2 transcripts in cultured fat body became less abundant after 20-hydroxyecdysone treatment. Thus, PAP-2, HP12, and HP24 mRNA levels are differentially regulated by immune and developmental signals. Comparison with HP15, HP23, and PAP-3 sequences suggested an evolutionary pathway of the dual clip-domain serine proteinases in M. sexta.

5' Flanking Region↗

PubMed2005

QSPR study on soil sorption coefficient for persistent organic pollutants.

Quantitative structure-property relationship (QSPR) models of soil sorption coefficients for 32 persistent organic pollutants were constructed using our recently introduced Lu index and novel distance-based atom-type DAI topological indices. Using multiple linear regression technique, a 6-variable model was obtained with the correlation coefficient of estimations (R) being 0.95, and the standard error of estimations (s) being 0.23, and the correlation coefficient (R(cv)) and the standard error (s(cv)) in the leave-4-out cross-validation procedure are 0.90 and 0.31, respectively. The results in this study indicate that soil sorption coefficients of POPs are dominated by molecular size while some DAI indices have smaller influence.

Adsorption↗

PubMed2005

Molecular targeting of BCL2 and BCLXL proteins by synthetic BCL2 homology 3 domain peptide enhances the efficacy of chemotherapy.

Chemotherapeutic agents are known to induce programmed cell death or apoptosis. The activation of cellular antiapoptotic defense that prevents the translation of drug-induced damage into cell death is the key factor in cellular antiapoptotic resistance that decreases the chemotherapeutic effectiveness of a broad spectrum of anticancer drugs. A novel proapoptotic anticancer drug delivery system (DDS) was designed to simultaneously induce apoptosis and suppress antiapoptotic cellular defense. The system includes three main components: 1) anticancer drug camptothecin (CPT) as an apoptosis inducer, 2) synthetic BCL2 homology 3 domain (BH3) peptide as a suppressor of cellular antiapoptotic defense, and 3) poly(ethylene glycol) (PEG) polymer as a carrier. The above DDS was studied in vitro using A2780 human ovarian carcinoma cells and in vivo on nude mice bearing xenografts of human ovarian tumor. The results obtained in both series of experiments corroborate each other. They show that the designed DDS provided intracellular delivery of active components and suppressed cellular antiapoptotic defense, leading to the more pronounced induction of caspase-dependent signaling pathway of apoptosis compared with CPT alone and simple CPT-PEG conjugate. Including BH3 peptide in complex DDS decreased apoptotic cellular defense, substantially increased toxicity of the whole complex, and provided high antitumor activity. Therefore, the proposed novel multicomponent proapoptotic anticancer drug delivery system has high potential to enhance the efficacy of chemotherapy.

Amino Acid Sequence↗

PubMed2005

Observation of a one-dimensional adsorption site on carbon nanotubes: adsorption of alkanes of different molecular lengths.

Three well-defined adsorption sites have been found on opened single-wall carbon nanotubes by temperature-programmed desorption measurements for several alkanes. A series of linear chain alkanes from pentane to nonane, as well as a branched alkane molecule, 2,2,4-trimethylpentane, were used to elucidate the effect of molecular length on the capacity of the adsorption sites. The two highest-energy adsorption sites were assigned as the nanotube interior sites and groove sites on the outside of the nanotube bundles. Hybrid Monte Carlo simulations were performed to probe the molecular-level details of adsorption. Both in experiments and in the simulation, the groove sites were seen to behave as one-dimensional adsorption space, demonstrating an inverse dependence of capacity on the length of the adsorbed molecule. In contrast, the capacity of the internal sites was found to depend inversely on the volume occupied by the molecule.

Journal Article↗

PubMed2005

Antitumor activity of poly(ethylene glycol)-camptothecin conjugate: the inhibition of tumor growth in vivo.

Antitumor effect of poly(ethylene glycol)-camptothecin conjugate (PEG-CPT) was studied in the nude mouse model of human colon cancer xenografts. The animals were treated intravenously with 15 mg/kg of camptothecin (CPT) or PEG-CPT conjugate at equivalent CPT dose. Antitumor activity, apoptosis induction and caspase-dependent signaling pathways were studied 12, 24, 48 and 96 h after single injection. In addition, pharmacokinetics, tumor distribution and accumulation of PEG polymer labeled with green fluorescence protein (GFP) were studied. The data obtained showed that the conjugation of low molecular weight anticancer drug CPT with low solubility to high molecular weight water-soluble PEG polymer provides several advantages over the native drug. First, the conjugation improves drug pharmacokinetics in the blood and tumor. Second, such conjugation provides passive tumor targeting by the Enhanced Permeability and Retention (EPR) effect, increasing drug concentration in the tumor. Third, the coupling increases the bioavailability of CPT, induces apoptosis in tumor and, therefore, enhances anticancer activity of PEG-CPT. Thus, the use of macromolecular conjugate provided passive tumor targeting of the drug, improved pharmacokinetics and increased the stability of the drug during circulation. It offered better uptake by the targeted tumor cells and substantially enhanced apoptosis and antitumor activity of the conjugated drug in the tumor and decreased apoptosis in liver and kidney as compared with the native drug. All these characteristics make PEG-CPT conjugate an attractive anticancer drug for the effective chemotherapy of solid tumors.

Animals↗

PubMed2005

Molecular cloning and expression pattern of 14 kDa apolipoprotein in orange-spotted grouper, Epinephelus coioides.

A novel fish-specific apolipoprotein (apo-14 kDa) has been recently cloned from eel and pufferfish. However, its expression pattern has not been elucidated. In this study, EcApo-14 has been screened from hypothalamic cDNA library of male orange-spotted grouper, which shows 62.9%, 51%, 46.9%, 43.2%, and 31.9% identities to Apo-14 of European flounder, pufferfish, Japanese eel, gibel carp, and grass carp, respectively. RT-PCR analysis reveals that this gene is first transcribed in neurula embryos and maintains a relatively stable expression level during the following embryogenesis. EcApo-14 transcripts are at a very high level during embryonic and early larval development in the yolk syncytial layer (YSL), and decrease in YSL and form intense staining in liver at 3 days after hatching. In adult tissues, EcApo-14 is predominantly expressed in liver and brain. The data suggested that EcApo-14 might play an important role in liver and brain morphogenesis and growth.

Amino Acid Sequence↗

PubMed2005

NK-cell activation by LIGHT triggers tumor-specific CD8+ T-cell immunity to reject established tumors.

Natural killer (NK) cells are generally reported as innate effector cells for killing virally infected and transformed cells. It is unclear how NK cells evoke adaptive immunity to eradicate tumors. We now demonstrate that the TNF superfamily member, LIGHT, known as TNFSF14 and a T-cell costimulatory molecule, is a critical ligand for the activation of NK cells. Herpesvirus entry mediator (HVEM) is expressed on NK cells, and its engagement with LIGHT mediates NK-cell activation. The expression of LIGHT inside tumors leads to rapid rejection in a NK-dependent manner. Both NK and CD8+ cells are essential but not sufficient for the rejection of tumors because mice lacking either population fail to reject the tumor. Interestingly, activated NK cells do not kill tumors directly but can facilitate the priming of tumor-specific CD8+ T cells in an IFN-gamma-dependent manner. Conversely, intratumor depletion of either NK cells or IFN-gamma during tumor progression disrupts CD8+ cell-mediated tumor rejection, suggesting that the tumor is the essential site for the crosstalk between NK and CD8+ cells. Furthermore, IFNG-deficient NK cells fail to effectively activate CD8+ T cells, suggesting IFN-gamma plays an important role in NK-mediated activation of cytotoxic T lymphocytes (CTLs). Our findings establish a direct role for LIGHT in NK activation/expansion and a critical helper role of activated NK cells in priming CD8+ T cells and breaking T-cell tolerance at the tumor site.

Animals↗

PubMed2005

N-Methylthio beta-lactam antibacterials: effects of the C3/C4 ring substituents on anti-MRSA activity.

N-Thiolated beta-lactams are a new family of antibacterials that inhibit the growth of Staphylococcus bacteria. Unlike other beta-lactam drugs, these compounds retain their full antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) strains and operate through a different mode of action. The structural features, which give these lactams their biological activity, have not yet been completely defined. Earlier efforts in our laboratory established that the N-organothio substituent is essential for antimicrobial activity while other groups at C(3) and C(4) on the lactam ring play a more subtle role. In this present study, we investigate these effects by varying the polar and steric nature of the ring substituents at these two centers. From the data presented herein, it appears that there is a need to balance the lipophilic character of the C(3)/C(4) groups to obtain an optimal anti-MRSA activity. The structure-bioactivity profiles more closely relate to the compound's ability to penetrate the bacterial cell membrane to sites of action within the cytoplasm rather than to any specific non-bonding interactions with a biological target. Based on these results, a model for the compounds' mode of action is presented.

Anti-Bacterial Agents↗

PubMed2005

Grain-size effect on the structure and antiobesity activity of konjac flour.

The effect of high-frequency oscillatory type ball-mill treatment on the structure and antiobesity activity of konjac flour was investigated. The grain size of konjac flour changed from 657.3 microm (d(50)) to 23.7 microm (d(50)) after 4 h of treatment. The structural change of the konjac flour with different grain size was characterized by using X-ray diffraction (XRD) differential scanning calorimetry (DSC). The results indicated that the crystallinity decreased and the diffraction peak drifted not only by when the crystallization region was reduced but also when the crystalline structure was changed. With the decrease of the grain size and crystallinity, the konjac flour grain, especially the 4 h milled konjac flour, swelled more rapidly and led to the improvement of the antiobesity effect. Compared with the native konjac flour, the 4 h milled konjac flour could significantly decrease the body weight and total wet weight of fat of nutritional obese rats (P < 0.05) and also decreased the contents of triglyceride, glucose, and high-density lipoprotein in blood of nutritional obese rat significantly (P < 0.05), which meant the grain-size effect of konjac flour improved its antiobesity activity notably.

Amorphophallus↗

PubMed2005

Oxygenated hydrocarbon ionic surfactants exhibit CO2 solubility.

Several oxygenated hydrocarbons, including acetylated sugars, poly(propylene glycol), and oligo(vinyl acetate), have been used to generate CO2-soluble ionic surfactants. Surfactants with vinyl acetate tails yielded the most promising results, exhibiting levels of CO2 solubility comparable to those associated with fluorinated ionic surfactants. For example, a sodium sulfate with single, oligomeric vinyl acetate (VAc) tails consisting of 10 VAc repeat units was 7 wt % soluble in CO2 at 25 degrees C and 48 MPa. Upon introduction of water to these systems, only surfactants with the oligomeric vinyl acetate tails exhibited spectroscopic evidence of a polar environment that was capable of solubilizing the methyl orange into the CO2-rich phase. For example, a single-phase solution of CO2, 0.15 wt % sodium bis(vinyl acetate)8 sulfosuccinate, and water, at water loading (W) values ranging from 10 to 40 at 25 degrees C and 34.5 MPa, exhibited a methyl orange peak at 423 nm. This result indicated that the core of a reverse micelle provided a microenvironment with a polarity similar to that of methanol. Quantum chemical calculations indicate that the acetylated sugars may be too hydrophilic to readily form reverse micelles, whereas the VAc-based surfactants appear to have the correct balance of hydrophilic and hydrophobic forces necessary to form reverse micelles.

Carbon Dioxide↗

PubMed2005

Octadecyl immobilized surface for precipitate collection with a renewable microcolumn in a lab-on-valve coupled to an electrothermal atomic absorption spectrometer for ultratrace cadmium determination.

Octadecyl immobilized surface was, for the first time, proved to be a superb precipitate-collecting medium. Surface charge effect was assumed to dominate the adsorption of cadmium hydroxide precipitate, facilitated by electrostatic interaction between the negatively charged C18 bead surface and positively charged cadmium hydroxide clusters. Residual silanol groups on the C18-immobilized silica surface did not contribute to precipitate adsorption. A novel procedure for ultratrace cadmium preconcentration was proposed by incorporating a renewable microcolumn in a lab-on-valve system. Cd(OH)(2) precipitate was adsorbed onto the C18 surface, which was afterward eluted with 20 microL of nitric acid (1%) and quantified with detection by electrothermal atomic absorption spectrometry. An enrichment factor of 28 and a limit of detection of 1.7 ng L(-1), along with a sampling frequency of 13 h(-1) were obtained with a sample consumption of 600 microL within the concentration range of 0.01-0.2 microg L(-1), achieving a precision of 2.1% RSD at the 0.05 microg L(-1) level. The enrichment factor was further enhanced to 44 by increasing the sample volume to 1200 microL. The procedure was validated by analyzing cadmium in three certified reference materials, that is, river sediment (CRM 320), sea lettuce (CRM 279), and frozen cattle blood (GBW 09140). Good agreement between the obtained results and the certified values was achieved.

Absorption↗

PubMed2005

[Combined therapy for stage IIIa non-small cell lung cancer].

OBJECTIVE: To evaluate the long-term outcome of combined therapy for stage IIIa non-small cell lung cancer (NSCLC). METHODS: Eight and twelve patients with stage IIIa NSCLC, 662 males and 150 females, aged 58.6 (24-79), underwent surgical resection, 326 of which received pre- and postoperative chemotherapy and/or radiotherapy, and 486 of which received surgery alone. The patients were classified according to the TNM staging, and the specimens of resected cancer were examined pathologically. The clinical data of these patients were analyzed. RESULTS: The overall 5-year survival rate was 16.4%. The 5-year survival rate of the combined therapy group was 23.5%, significantly higher than that of the surgical resection alone group (P < 0.01). The 5-year survival rate was 27.6% for the squamous cell carcinoma (SCC), and 23.5% for adenocarcinoma (AC) in the combined therapy group; and was 115.2% for SCC and 9.9% for AC in the surgical resection alone group (all P < 0.01). CONCLUSION: The curative effectiveness of combined therapy is significantly better than surgical resection alone for stage IIIa NSCLC. However, The combination should be based on the TNM staging and pathological type.

Adenocarcinoma↗