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Biomedical subjects

M Wang

Publications and source records attributed to M Wang.

At least 487 records · Page 27Linked to original sources
PubMed1999

[Development of column switching systems in industrial gas chromatography].

According to the home-made requirement of column switching systems in 23 industrial gas chromatographs in 300,000 Tons of olefin plant, based on the research work of the expert system on gas chromatography and movement laws of compounds of interest in columns, the suitable stationary phases were defined, and the column switching systems were designed by using combined cutting techniques which consist of backflushing, fore-flushing and heart cutting, and by controlling column lengths, flows, flow directions and temperatures. The practical applications showed the column systems satisfy the on-line monitoring requirement of the production process and can be used continually for 1-3 years.

English Abstract↗
PubMed1999

[Light-dependent incorporation of selenite into selenocysteine by isolated chromatophore of Chromatium vinosum].

Illiminated intact chromatophore of chromatium vinosum in the presence of O-acetylserine(OAS) catalysed incorporation of SeO3(2-) into selenocysteine at rate of 359 nmol.mgBchl-1.h-1. Sonicated chromatophore catalysed SeO3(2-) incorporation at 1.1% of the rate of intact chromatophore. Addition of GSH and NADPH increased the rate to 88.3% of intact rate, but SeO3(2-) incorporation under these conditions was essentially light dependent. The purified GSH reductase from Chromatium vinosum in the presence of cysteine synthase OAs and NADPH catalysed incorporation of SeO3(2-) into selenocysteine. It is proposed that SeO3(2-) is reduced by light-coupled GSH reductase and that Se2- produced is incorporated into selenocysteine by cysteine synthase.

Catalysis↗
PubMed1999

[Isolation and quantitation of chloroquine-binding proteins in Plasmodium berghei].

AIM: To isolate and quantitate chloroquine (CQ)-binding proteins in both CQ-sensitive (CS) AND CQ-resistant (CR) Plasmodium berghei. METHODS: P. berghei infected mice were each given i.g. CQ 400 mg/kg, respectively, 3 h later, the proteins of the parasites collected were separated using Ultrogel AcA34 gel column, followed by CQ extraction, the CQ concentration was determined by HPLC (extra standard). RESULTS: There were 58 protein peaks in the CS, all of which were bound with CQ, fraction Nos. 64-86 (peak 9) being the predominant, accounting for 16.4% of the total amount of CQ-binding protein. In the CR there were 40 protein peaks, among which 32 were bound with CQ, the predominant fraction Nos. 60-83 (peaks 6, 7), had a higher CQ-binding ability than CS. CONCLUSION: The distribution and amount of each CQ-binding protein peak in both CS and CR strains of P. berghei were demonstrated, exhibiting differences in the ability of CQ-binding not only between CS and CR strains but also within the same strain.

Animals↗
PubMed1999

[Anti-hemolytic and anti-membranous lipid peroxidation effects of daphnetin].

AIM: To investigate the anti-hemolytic and anti-membranous lipid peroxidation effects of daphnetin. METHODS: The inhibition rates of daphnetin on AQD-induced hemolysis and erythrocytic membranous lipid peroxidation were determined by routine in vitro assay for detecting hemolytic toxicity and by HPLC for detecting membranous lipid peroxidation products. RESULTS: Daphnetin at a range of 10-80 mumol/L inhibited dose-dependently AQD-induced hemolysis and lipid peroxidation by 33.0%-69.2% and 11.9%-58.2%, respectively. CONCLUSION: Daphnetin has anti-hemolytic and anti-erythrocytic membranous lipid peroxidation effects.

Aminoquinolines↗
PubMed1999

[Surgical reconstruction of laryngeal and tracheal stenosis].

OBJECTIVE: Reconstruction of laryngotracheal stenosis. METHOD: According to the pathologic condition of the larynx and trachea, various surgical procedures were designed for the treatment of laryngotracheal stenosis. These techniques included endoscopic management, laser therapy and laryngotrachoetomy with autogenous tissue and stent. RESULT: Among 36 patients, 32 were decannulated. The success rate was 88.8%. CONCLUSION: In order to improve the curation effects of laryngjotrachal stenosis, the choice of surgical procedure must be individualized to the pathologic condition of larynx and trachea, as well as the experience of the surgeon. Learning previous successful experience is also very important for a good result.

Adolescent↗
PubMed1999

[Angiotensin II regulates the expression of collagens in rat heart].

OBJECTIVE: To testify the effect of angiotensin (Agn) II on the regulation and expression of collagen I, III genes in rat heart as well as the influence of DMP811 (a novel nonpeptide selective angiotension type 1 antagonist) on the effect of Ang II. METHODS: Six-week-old male SD rats with osmotic minipump subcutaneously containing either Ang II or saline were used. (1) Saline-infused(control) group (n = 6), (2) Ang II-infused group (n = 6). (3) Ang II-infused and DMP811-treated (3 mg.kg-1.d-1, by gavage) group (n = 6). Ang II (200 ng.kg-1.min-1) or saline was continuously infused for 1 week. After extraction of cardiac total RNA, the levels of collagen I, III mRNA and proteins were measured with RT-PCR and Sirius red staining respectively. RESULTS: Cardiac weight, cardiac weight/body weight radio, the mRNA levels of collagen I, III were increased by (4.7 +/- 0.4)%, (4.9 +/- 0.9)%, (22.0 +/- 4.7)% and (20.6 +/- 4.9)% respectively, in group 2 compared with those in group 1. The analysis of collagen on Sirius red-stained sections showed that Ang II increased the deposits of both collagen I and III. The above changes caused by Ang II could be inhibited fully by DMP811. CONCLUSIONS: Ang II up-regulated the expressions of collagen I, III via angiotension type 1 receptor.

Angiotensin II↗
PubMed1999

[Grey relational analysis on early bolting of Angelica and its main factors].

Selecting the principal environmental and cultivated factors from the main production areas of Angelica sinensis in Gansu, the problem of early bolting were analysed with grey system theory. After the quantitative analysis, the relational grade was: elevation > precipitaton > density of crop > organic fertilizer > phosphorus fertilizer > nitrogen fertilizer. The research would provide scientific basis for check on the rate of the early bolting of Angelica effectively as well as improve the product and benefits.

Altitude↗
PubMed1999

[Nucleotide sequence of A/Goose/Guangdong/2/96 (H5N1) virus M and NS RNA].

OBJECTIVE: To determine the nucleotide sequences of M and NS genes of A/Goose/Guangdong/2/96(H5N1) virus and also to compare them with the sequences of A/HK/156/97(H5N1) strain for revealing the relationship between the two viruses, as well as for setting up a solid base for studying M and NS genes of influenza A viruses in the future. METHODS: Virion RNA was transcribed into cDNA by reverse transcriptase, cDNA was amplified by PCR, the products of PCR were purified. Afterward, RNA sequence analysis was performed by the dideoxynucleotide chain termination method using synthetic oligodeoxynucleotide primers. RESULTS: The segment length of A/Goose/Guangdong/2/96(H5N1) virus RNA 7 is 1,027 nucleotides. It codes M1 (252 amino acids) and M2 (97 amino acids) proteins. However, the segment length of RNA 8 of A/Goose/Guangdong/2/96(H5N1) virus is 890 nucleotides coding NS1 (230 amino acids) and NS2 (121 amino acids) proteins. The amino acid sequence homologies of M1, M2, NS1 and NS2 protein molecules between A/Goose/Guangdong/2/9(H5N1) and A/HK/156/97 (H5N1) viruses are 97.6%, 92.8%, 65.7% and 76.9%, respectively. CONCLUSION: The lengths of A/Goose/Guangdong/2/96(H5N1) virus RNA 7 and RNA 8 and 1,027 are 890 nucleotides, respectively. These two RNA segments belong to those of avian influenza A virus. The A/HK/156/97(H5N1) virus RNA 7 and RNA 8 segments are not derived from those of A/Goose/Guangdong/2/96(H5N1) virus directly.

Amino Acid Sequence↗
PubMed1999

[Studies on decomposed crop residues by FTIR differential analysis].

The decomposing process of corn leaf residues (CLR) was studied by FTIR differential analysis, and the differential spectra were compared with normal spectra. The result showed that the purification process to remove inorganic matters from decomposed CLR could be omitted when differential analysis is used, and the differential spectra were clear and distinct. As far as the studies of decomposed crop residues, the FTIR differential analysis was a convenient and forthright method.

Spectroscopy, Fourier Transform Infrared↗
PubMed1999

[Study on application of crosslinked chitosan to the speciation analysis of selenium].

The adsorption of Se(IV)/Se(VI) by crosslinked chitosan was studied and the adsorption mechanism was concerned. The results indicated that the adsorption of Se(VI) was 95% at pH=4, while almost no adsorption for Se(IV). The adsorbed Se(VI) was quantitatively desorbed with 1 mol/L HCl after adsorption of Se(VI). A new method for the determination of trace Se(IV)/Se(VI) and organic selenium in environmental samples with hydride generation and atomic absorption spectphotometry has been developed. The detection limit of this method was 20 ng/L, the recovery was 93%-106% and the coefficient of variation was 2.0%-5.0%.

Adsorption↗
PubMed1999

[Study on syntheses and spectroscopic property of complexes of quinoxaline-2,3-dicarboxamide with transition metals].

Three new solid complexes of transition metal Co(II), Ni(II) and Cu(II) with quinoxaline-2,3-dicarboxamide were synthesized, and the composition of the complexes was confirmed to be M(Qxda)2Cl2 [M = Co(II), Ni(II), Cu(II)] by elemental analysis, molar conductance and thermal analysis. The coordination pattern and structure were discussed by infrared spectra, electronic spectra.

English Abstract↗
PubMed1999

Interleukin-6 modulated conditionally replicative adenovirus as an antitumor/cytotoxic agent for cancer therapy.

In this study, we report that an interleukin-6 (IL-6)-inducible E1A-substituting activity can be exploited for the production of infectious adenoviral particles during infection with the E1A-deleted adenovirus (Ad) Ad5dl312. The basal level of complementation can be increased by 1.5 log by induction of the HepG2 cells with recombinant human IL-6. Additionally, the IL-6-inducible E1A-substituting activity can complement E1A deletion in other cancer cell lines to render them Ad producer cells on induction with recombinant human IL-6, although the efficiency of complementation varies between cell lines. Ad5dl312 can replicate in, produce cytotoxic effect, and kill human tumor cells without addition of exogenous IL-6 in the context of tumor cells possessing an IL-6 autocrine arc, such as ovarian tumor cells. In contrast, normal human mesothelial cells isolated from normal human peritoneum lining do not support replication of Ad5dl312, even in the presence of exogenous IL-6. These results suggest that Ad5dl312 could be used as a cytotoxic agent to selectively kill tumor cells responsive to or possessing an IL-6 autocrine arc.

Adenoviridae↗
PubMed1999

Interleukin 10 (IL-10) inhibition of primary human prostate cell-induced angiogenesis: IL-10 stimulation of tissue inhibitor of metalloproteinase-1 and inhibition of matrix metalloproteinase (MMP)-2/MMP-9 secretion.

In in vitro angiogenesis assays, aggregates of human papilloma virus (HPV)-18-immortalized primary human prostate cancer cells (HPCA-5aHPV-18 or HPCA-10aHPV-18 cells) induced human bone marrow endothelial cells (HBMCE-1 cells) to form microvessels in three-dimensional collagen I gels after 1-2 days incubation at 37 degrees C. The microvessels aligned perpendicular to the tumor aggregates and abutted on the edges of the aggregates. The number and length of the microvessels increased significantly from day 1 to 2 (i.e., by approximately 30%). ELISAs showed that the HPCA-5aHPV-18 cells normally secreted low levels of tissue inhibitor of metalloproteinase (TIMP)-2, matrix metalloproteinase (MMP)-2, and MMP-9 but relatively high levels of TIMP-1. In contrast, HPCA-10aHPV-18 cells secreted high levels of MMP-2 and MMP-9 (>40 pg/microg protein) but low levels of TIMP-1 and TIMP-2 (<5 pg/microg protein). Interleukin 10 (IL-10) (15 ng/ml) induced TIMP-1 production (>15 pg/microg protein) but reduced MMP-2 and MMP-9 secretion (<5 pg/microg protein) by the HPCA-5aHPV-18 and HPCA-10aHPV-18 cells. IL-10 (15 ng/ml) and MMP-9/MMP-2 antibodies all blocked induction of microvessel formation in the coculture experiments. In contrast, IL-10 receptor antibodies and TIMP-1 antibodies countered IL-10's effects and promoted angiogenesis. The data demonstrated that IL-10 stimulation of TIMP-1 and inhibition of MMP-2 and MMP-9 secretion by prostate tumor cells can control induction of angiogenesis in vitro.

Antibodies↗
PubMed1998

Bioglass/high density polyethylene composite for soft tissue applications: preparation and evaluation.

Particulate 45S5 Bioglass with an average size of 46 microm was incorporated into a high density polyethylene (HDPE) for potential medical applications. Composites with Bioglass volumes of 10, 20, and 40% were produced by a manufacturing process consisting of blending, compounding, powdering, and compression molding. The Bioglass particles were well dispersed, and their homogeneous distribution in the polymer matrix, achieved after compounding, was retained during subsequent composite processing. The Young's modulus and microhardness of the composites increased with an increase in Bioglass volume while the tensile strength and fracture strain decreased. Fourier transform infrared spectra, obtained from Bioglass/HDPE samples exposed for 20 h at 37 degrees C to a simulated body fluid (SBF-9), demonstrated that composites of all the compositions examined developed the surface biological apatite layer equivalent to that for bulk Bioglass.

Biocompatible Materials↗
PubMed1998

Apoptotic death of CD8+ T lymphocytes after immunization: induction of a suppressive population of Mac-1+/Gr-1+ cells.

Following an infection or immunization, a primary CD8+ T cell response generally rises then falls rapidly before giving rise to a "memory" response. When we immunized mice with recombinant viral immunogens optimized to enhance the lytic capability of CD8+ T cells, we measured a profound depression in Ag-specific effector function after early restimulation. Indeed, a "mirror image" cytolytic capability was observed: the most powerful immunogens, as measured by cytolytic capacity 6 days after immunization, elicited the weakest secondary immune response when evaluated following an additional 6 days after restimulation. To understand the mechanism of this suppression, we examined the fate of splenocytes immunized with a vaccinia virus encoding Ag and IL-2 then restimulated ex vivo. We found that these splenocytes underwent an apoptotic cell death, upon early restimulation, that was not dependent on the engagement of the FasR (CD95). Unlike previously described mechanisms of "propriocidal cell death" and "clonal exhaustion," the cell death we observed was not an inherent property of the CD8+ T cells but rather was due to a population of splenocytes that stained positive for both the Mac-1 and Gr-1 surface markers. Deletion of these cells in vitro or in vivo completely abrogated the observed suppression of cytolytic reactivity of Ag-specific CD8+ T cells. These observations could account for the apparent absence of Ag-specific immune responses after some current vaccination regimens employing powerful immunogens. Finally, our results may shed new light on a mechanism for the suppression of CD8+ T cell responses and its effect on vaccine efficacy and on immune memory.

Animals↗
PubMed1998

[Comparison of genotype and intellectual phenotype in untreated phenylketonuric children].

OBJECTIVE: The main feature of phenylketonuria(PKU) is mental retardation. Although classical PKU is defined as that the hepatic phenylalanine hydroxylase (PAH) activity ranges 0-1% of normal enzyme, the untreated PKU patients show a wide range of intellectual phenotype. This study sought to find the molecular basis of such variation of intellectual phenotype among PKU. METHODS: 45 classical PKU patients included in the research were screened for detecting six mutant alleles which were rather common among Chinese PKU patients, i.e. R243Q, R413P, Y204C, Y356X, W326X and R111X. PCR-ASO and PCR-SSCP techniques were used. The expression of those mutant PAH genes was analysed by methods of site-directed mutagencies. 27 PKU patients whose two mutant alleles were both defined were involved in this study. The IQ of these patients were tested by DDST system. RESULTS: Among 27 patients, 4/27 (15%) were mild retardation, 10/27(37%) were moderate, the severe mental retardation accounted for 12/27(44%). The relationship between genotype and intellectual phenotype in this group was examined. It was found that the intellectual phenotype of 8 patients were compatible with genotype but not well matched in 19 cases. The enzyme activity of Y204C expressed in vitro was 100%, but all 3 patients with Y204C/Y204C were severely mental retarded. Enzyme activities of R413P and Y356X were <3% and 0 respectively in expression analysis, but the patients in this group had mild or moderate mental retardation. CONCLUSION: Intellectual phenotype was not well matched with the genotype in classical PKU patients, so that genotype can not be used to predicte the intellectual phenotype in PKU patients.

Child↗