Biomedical subjects

Yan Wang

Publications and source records attributed to Yan Wang.

At least 559 records · Page 31Linked to original sources

PubMed2002

Conservation of the class I beta-tubulin gene in human populations and lack of mutations in lung cancers and paclitaxel-resistant ovarian cancers.

The goal of this study was to determine the prevalence of sequence variants in the class I beta-tubulin (clone m40) gene and their occurrence in human tumors and cancer cell lines. DNA was isolated from 93 control individuals representing a wide variety of ethnicities, 49 paclitaxel-naive specimens (16 ovarian cancers, 17 non-small cell lung cancers, and 16 ovarian cancer cell lines), and 30 paclitaxel-resistant specimens (9 ovarian cancers, 9 ovarian cancer cell lines, and 12 ovarian cancer xenografts in nude mice). Denaturing high-performance liquid chromatography and direct sequence analysis detected two silent polymorphisms in exon 4, Leu217Leu (CTG/CTA) and Gly400Gly (GGC/GGT), with minor allele frequencies of 17 and 0.5%, respectively. Five nucleotide substitutions and one single-base deletion were detected in introns 1, 2, and 3 and in the 3' untranslated region. Analysis of 49 paclitaxel-naive and 30 paclitaxel-resistant specimens revealed no additional polymorphisms in the coding region. In addition, no amino acid replacements were found in chimpanzee, gorilla, and orangutan in comparison to human. Our data demonstrate a very high degree of sequence conservation in class I beta-tubulin, suggesting that all residues are important in tubulin structure and function. Individual variation in response to treatment with paclitaxel is not likely to be caused by genetic variations in the beta-tubulin drug target. Moreover, acquired mutations in class I beta-tubulin are unlikely to be a clinically relevant cause of drug resistance.

Animals↗

PubMed2002

[Study on a test of screening to predict stroke-using cerebral vascular hemodynamic indexes].

OBJECTIVE: To evaluate efficacy and optimal cut-off-point through cerebral vascular hemodynamic indexes (CVHI) examination to predict stroke. METHODS: A number of 20,333 people at 35 years old and over were checked by CVHI and accumulative score was calculated according to the value of detected indexes. Risk factors of stroke were investigated simultaneously. One hundred and sixty-eight patients with stroke occurred during 4-year following up. Typical syndromes and signs stroke were used as golden standard to evaluate screening efficacy of CVHI. RESULTS: Score of optimal cut-off-point of cerebral vascular hemodynamic indexes was under 75 in ROC curve analyses. Sensitivity, specificity, accuracy, positive and negative predictive values, positive and negative likelihood ratios as well as Youden's index for predicting stroke within 4 years after examination were found to be 87.50%, 67.70%, 67.86%, 2.21%, 99.85%, 2.71, 0.18 and 0.55 respectively. Sensitivity and positive predict values for predicting cerebral vascular thrombosis were superior to predicting cerebral hemorrhage. Positive predicting value in risk exposure population was higher than that of overall population. Coefficiency of variation of cerebral vascular hemodynamic examination was 4.03%. The agreement rate of examination between two physicians was 97.62% and Kappa value was 0.94. CONCLUSION: The score of optimal cut-off-point of cerebral vascular hemodynamic indexes examination was 75. Both Efficacy and reliability for predicting stroke seemed to be good, especially for predicting cerebral vascular thrombosis.

Adult↗

PubMed2002

[Significance of fatty acid synthase expression in non-small cell lung cancer].

OBJECTIVE: To evaluate the expression of fatty acid synthase (FAS) in non-small cell lung cancer (NSCLC). METHODS: FAS was examined by immunohistochemical S-P technique in 175 specimens of NSCLC patients. Multiple clinical factors were analyzed according to their relation with expression of FAS. RESULTS: The overall FAS expression rate was 31.4% (55/175). The expression of FAS in the non-adenocarcinoma patients was significantly higher than that of adenocarcinoma patients (38.4% vs 22.4%, P = 0.036). Higher FAS expression was also detected in patients who had vascular invasion or bone metastasis than those without (75.0% vs 29.3%, P = 0.02 and 46.9% vs 28.0%, P = 0.037). But, there was no significant difference between FAS and other clinical factors such as age, sex, smoking index, tumor size, stage, degree of differentiation, lymphatic metastasis, local recurrence or distant metastasis. Although there was no significant difference in the survival rates of FAS positive and negative patients (P = 0.066), the survival rate of FAS positive stage I patients was lower than that of negative ones (P = 0.005). CONCLUSION: Fatty acid synthase in the specimens of non-small cell lung cancer patients has no correlation with most clinical factors, except that, in early lesions, it may signify poor prognosis.

Adult↗

PubMed2002

Neutralizing anti-insulin-like growth factor receptor 1 antibodies inhibit receptor function and induce receptor degradation in tumor cells.

Insulin-like growth factor receptor 1 (IGFR1) plays a crucial role in oncogenic transformation [C. Sell et al., Mol. Cell. Biol., 14: 3604-3612,1994]. Compared with the normal human mammary epithelial cell line MCF12A, MCF7 human mammary carcinoma cells overexpress IGFR1 on the cell surface. To measure the effects of IGFR1 inhibition on tumor cells, we tested two mouse neutralizing antibodies against human IGFR1 in cell-based assays. Both MAB391 and anti-IR3 antibodies inhibit IGFR1 autophosphorylation upon IGF-I ligand stimulation with IC50s of 0.58 and 0.80 nM, respectively. When cells were treated with neutralizing anti-IGFR1 antibodies for > or = 4 h, the total receptor level was dramatically decreased. IGF-I-stimulated activation of AKT was also inhibited by anti-IGFR1 antibodies. Furthermore, MAB391 and anti-IR3 inhibited the growth of MCF7 cells in soft agar. In addition to MCF7 cells, MAB391 also inhibited IGFR1 autophosphorylation and induced IGFR1 down-modulation in HT29 colorectal and Du145 prostate cancer cells. Therefore, neutralizing antibodies against IGFR1 represent a valid approach to inhibit growth of tumor cells.

Agar↗

PubMed2002

[A fiber optic chemical sensor system for on-line monitoring the drug dissolution of rifampicin].

AIM: To study a continuous, on-line and automatic monitoring method for dissolution of drugs. METHODS: A new fiber optical chemical sensor prepared by sol-gel immobilization of molecular probe was reported. Based on multiple quenching of flurescence, an instrument and software system was designed to on-line monitor the drug dissolution of rifampicin. RESULTS: The concentration of rifampicin was linear with ln(F0/F) when concentration was in the range of 10-170 micrograms/mL-1. The relative coefficient was 0.9993. The procession of dissolution can be on-line monitored. Parameters were obtained directly from the dissolution curve. There is no distinctly difference when compared with the method of the Pharmacopoeia of People's Republic of China (P > 0.05). CONCLUSION: This procession analysis can reflect the real dissolution of drug and obtain the total information.

Antibiotics, Antitubercular↗

PubMed2002

[Study progress in Sinomenium acutum (Thunb.) Rehd. et Wils].

This article reviewed the progress in the study of the pharmacognosy, chemical compositions, pharmacological actions and clinical practices of Sinomenium acutum (Thunb.) Rehd. et Wils. An expectation for the further development and utilization of this plant was put forward.

Animals↗

PubMed2002

[Studies on the chemical constituents from Ampelopsis grossedentata].

OBJECTIVE: To study the chemical constituents from Ampelopsis grossedentata (hand-Mazz) W.T. Wang. METHODS: Chromatography and spectroscopic analysis were employed to isolate and elucidate the chemical constituents in the plant. RESULTS: Seven compounds were isolated and elucidated as ampelopsin (I), myricetin (II), myricitrin (III), gallic acid (IV), beta-sitosterol (V), stigmasterol (VI) and dihydroquercetin (VII). CONCLUSION: Among these compounds, IV, V, VI and VII were isolated from this plant for the first time, and compound VII was obtained from genus Ampelopsis for the first time.

Ampelopsis↗

PubMed2002

[Determination of ampelopsin in the different parts of Ampelopsis grossedentata in different seasons by RP-HPLC].

OBJECTIVE: To determine ampelopsin in the root, stem and leaf of Ampelopsis grossedentata in different seasons by RP-HPLC. METHODS: The determination was carried out with ODS column (5 microns, 250 mm x 46 mm), using methanol-water-phosphoric acid(25:75:0.1) as the mobile phase at a flow rate of 1.0 ml/min and detected at the wavelength 289 nm. RESULTS: Ampelopsin content was in the order of leaf > stem > root. Ampelopsin content in Ampelopsis grossedentata collected in April and May was the highest.

Ampelopsis↗

PubMed2002

[Arthroscopy for the diagnosis and treatment of hip joint disease].

OBJECTIVE: To evaluate the value of arthroscopy for the diagnosis and treatment of hip joint disease. METHODS: Arthroscopy was performed in 54 patients (68 hips) from July 1998 to September 2001. Of the 54 patients, 36 were male and 18 female, aged from 17 to 64 years. The disease was located on the left side in 18 patients, the right side in 22, and both sides in 14. In this group, osteoarthritis was noted in 21 patients, avascular necrosis of the femoral head in 16, infection of the hip joint in 3, chondrosarcoma in 2, synovial-chondromatosis in 7, acetabular labral tears in 2, and spondylitis in 3. The procedures of arthroscopy consisted of removal of loose bodies, debridement, and biopsy. RESULTS: The operation made accurate diagnosis possible for chondrosarcoma, acetabular labral tears, and infection of the hip joint. After debridement of the hip joint for avascular necrosis of the femoral head, osteoarthritis and spondylitis, most patients in this group were free from pain, function and range of the motion were restored and the pathological process was delayed. The Harris hip scores increased by 27 on average. CONCLUSION: Arthroscopy plays an important role in accurate diagnosis and treatment of hip joint.

Adolescent↗

PubMed2002

[Antiviral effect of recombinant antibody to influenza virus HA antigen].

OBJECTIVE: Study on the antiviral effect in vivo and in vitro of recombinant antibodies with neutralization activity to influenza virus HA antigen, IgG-IV-2 and IgG-IV-6 obtained from expression in Baculo/insert system. METHODS: Viral titer of influenza virus in MDCK was compared before and after antibody application, and measured viral titer in mouse lung before and after antibodies applied on mucous membrane. RESULTS: IgG-IV-2 and IgG-IV-6 could reduce the titer from 4.5 log10 TCID50 to half is by 50% at doses 0.8 microg and 0.5 microg respectively. When recombinant antibodies were used on mucous membrane, the IgG-IV-2 and IgG-IV-6 reduced the titer by half at doses 0.25 mg/kg weight and 0.1 mg/kg weight respectively. The dose was 0.08 mg/kg weight when the two antibodies were jointly used. CONCLUSIONS: The recombinant antibodies have antiviral effect in vivo and in vitro, they can neutralize viral virulence.

Animals↗

PubMed2002

[Preliminary investigation on the relation between clinical progress and anti-small monomolecular peptides antibody in individual infected with HIV].

OBJECTIVE: To study the quantity of anti-R7V in individuals infected with HIV and AIDS patients and its relation with the progression of disease. METHODS: ELISA and precipitation and other methods were used to investigate the quantity of anti-R7V in asymptomatic long-term survivors and AIDS patients. RESULTS: Positive rate and quantity of anti-R7V were higher in the HIV active ones and AIDS. It showed that the quantity and positive rate of anti-R7V were rather high in dissolving test. CONCLUSIONS: It is strong suggestion for anti-R7V to obstruct the replication of virus by interfering the connection between HIV with CCR5 or CXCR4 and so it impossible HIV entering to CD4+ T cells.

Acquired Immunodeficiency Syndrome↗

PubMed2002

Determination of the fractions of the stoichiometric displacement parameter Z.

Based on the stoichiometric displacement theory for adsorption (SDT-A) of solute, an equation expressing the linear relationship between the affinity of the solute to the adsorbent (beta a), and the logarithm of the molar concentration of the solvent in bulk solution (log alpha D), was derived. The terms n and q values (moles of the solvent separately released from the adsorbent and solute as one mole of solute is adsorbed), that are the fractions of the stoichiometric parameter Z (Z = n + q), were obtained from this quantitative relationship. The derived equation was tested by the derivatives of benzene under different methanol concentrations by frontal analysis of reversed-phase liquid chromatography (RPLC) and satisfactory results were obtained. Moreover, the terms n and q were tested with the presented method, and also examined by the combination of the SDT-A with stoichiometric displacement theory for retention (SDT-R). Both n and q were further validated to follow the homologue rule. More moles of the solvent were released by the adsorbent than by the solute (n > q) and the n value increases when the group attached to benzene was nonpolar.

Adsorption↗

PubMed2002

[Comparative study on anti-hypercholesterolemia activity of diosgenin and total saponin of Dioscorea panthaica].

OBJECTIVE: To compare the anti-hypercholesterolemic and cholesterol absorption inhibitory activities between total saponin of Dioscorea panthaica (TSDP) and diosgenin (Dio). METHOD: TSDP and Dio were given ig or i.p. to mice or rats treated with cholesterol feed to evaluate their preventive and therapeutic effect on hypercholesterolemia. TSDP or Dio and cholesterol were mixed with pig bile to form the micelle, then the freeing cholesterol was detected to evaluate inhibitory effect of the both compounds on cholesterol absorption. RESULT: Dio (80 and 160 mg.kg-1) showed significantly therapeutic and preventive effect on hypercholesterolemia in mice, while TSDP showed a certain preventive activity only at a big dose (400 mg.kg-1). The intraperitoneal injection of Dio (20 and 40 mg.kg-1) to mice suffered from hypercholesterolemia was effective, but TSDP showed no effective. The serum total cholesterol level was decreased when rats were pre-treated with TSDP (200 and 400 mg.kg-1, ig) and Dio (200 and 100 mg.kg-1, ig). However, the hypercholesterolemia-preventing activity of Dio was stronger than that of TSDP. In addition, inhibitory effect of Dio on cholesterol micelle formation was still stronger than that of TSDP. CONCLUSION: The preventive and therapeutic activity of Dio against hypercholesterolemia indused by cholesterol in mice or rats is stronger than that of TSDP. The anti-hypercholesterolemia mechanism of Dio is probably related with its cholesterol absorption inhibitory activity.

Animals↗

PubMed2002

[The antitumor activity of Diosgenin in vivo and in vitro].

OBJECTIVE: To investigate the antitumor activity of Diosgenin in vivo and in vitro. METHOD: S-180, HepA, U14 and EAC transplant mice were given Diosgenin ig or i.p. everyday for 10 days, from the next day when they were inoculated in axilla. Tumor growth inhibit rates were calculated. Four kinds of cells, MCF, L929, A375-S2 and HeLa, were incubated respectively with Diosgenin in vitro. Tumor growth inhibit rates were also calculated. RESULT: In vivo, both ig and i.p., Diosgenin inhibited S-180, HepA, U 14 mice transplant tumor, the inhibit rates being 30%-50%, but it did not inhibit the EAC mice transplant tumor. In vitro, Diosgenin inhibited L929, HeLa, MCF cell growth, and IC50 were 1.2, 18.2, 19.8 micrograms.mL-1 respectively, but it did not significantly affect A375-S2 cells. CONCLUSION: Diosgenin has an obvious antitumor activity on S-180, HepA, U14 transplant mice in vivo and L929, HeLa, MCF cells in vitro.

Animals↗

PubMed2002

[Study on the infinity optical thickness of light-cured composite resins and attached shade guides].

OBJECTIVE: This study compared the opaque characteristics of light-cured composite resins and attached shade guides. METHODS: Three kinds of light-cured composite resins and attached shads guides were used. A plastic mold (10mm in diameter and 4mm in height) was used to prepare disk specimens. Color was measured by CIE L*a*b* relative to CIE source against a white and a black background, using a colorimeter. Color change (DeltaE)was calculated as DeltaE=[(DeltaL*)(2)+(Deltaa*)(2)+(Deltab*)(2)](1/2). The heights of composite resins were recorded as DeltaE is approximately 1.5. The infinity optical thickness of composite resins when delta E*=1.5 was calculated by regression formulation. RESULTS: There was significant difference in color difference and the infinity optical thickness among materials and shades. The infinity optical thickness gradual decreased in the same shade mark from 1 to 4, and from A to D the results was not simple. CONCLUSION: There was significant difference in the infinity optical thickness between the attached shade guides and the resins materials. Composite resins contain micro-filler were inferior in infinity optical thickness.

English Abstract↗

PubMed2001

ICP-AES determination of traces of noble metal ions pre-concentrated and separated on a new polyacrylacylaminothiourea chelating fiber.

A new polyacrylacylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber) and aminothiourea. This fiber was used for the pre-concentration and separation of traces of AuIII, PtIV, PdIV, and IrIV ions from aqueous samples. Factors effecting and parameters for the adsorption of these ions onto the resin, such as acidity, rate, reuse, capacity, and interference of other ions, were investigated using inductively-coupled plasma atomic emission spectrometry (ICP-AES). Conditions of desorption of these ions from the resin were similarly investigated. The enrichment factor was 100. The relative standard deviation for the determination of AuIII, PtIV, PdIV, and IrIV were in the range of 0.7-3.0% for 20.0 ng/mL of each. The recoveries of a standard from real solution samples were between 96% and 100%. The concentrations of analyzed ions in a digested metal powder sample processed with the method proposed were in good agreement with the certified values.

Journal Article↗

PubMed2001

Transcriptionally active polymerase chain reaction (TAP): high throughput gene expression using genome sequence data.

An approach is described for making transcriptionally active PCR (TAP) fragments that were used directly in in vitro and in vivo expression experiments. TAP fragments encoding reporter genes were amplified in 1 day using typical PCR methodology and were expressed in cultured cells and in mice at levels comparable with a widely used cytomegalovirus promoter-based plasmid expression vector. Following intramuscular injection, a TAP fragment encoding hepatitis B surface antigen (HBsAg) induced anti-HBsAg antibody titers comparable with those induced by supercoiled plasmid encoding the same antigen. Epitope-tagged TAP fragments were generated and transfected into cells for rapid, high throughput immunocytochemical analysis of the tagged gene products. TAP fragments were also transferred directly into expression vectors by in vivo homologous recombination without conventional cloning, affording a high throughput cloning approach that does not require restriction enzyme digestion, ligations, or thymidine adenine complementation cloning. The methodology has been adapted to a robotic work station enabling the high throughput generation of transcriptionally active genes at the rate of more than 400 different genes per day. This technology offers a practical approach to directly utilize genome sequence data to generate functional proteomes.

Animals↗

PubMed1999

Secretory Expression of Human Insulin in Methylotrophic Yeast Pichia pastoris.

The porcine insulin precursor (PIP) gene and its derivative form sp-PIP gene, which had a nona-peptide (called spacer peptide, sp) added at the 5' terminus of PIP gene, were inserted into the plasmid pPIC9 of Pichia pastoris to obtain secretory plasmid pPIC9/PIP and pPIC9/sp-PIP, respectively. P.pastoris GS115 was transformed by pPIC9/PIP or pPIC9/sp-PIP and the high-copy strains, P39(-sp) and S51(+sp), were selected by dot-blotting. The expression levels of PIP and sp-PIP were 10 mg/L and 40 mg/L in 1 L shake flask, respectively, indicating that the spacer peptide could increase the expression. The expression level of PIP (sp-PIP) in P.pastoris was higher than that of PIP in S.cerevisiae and K.lactis reported in this laboratory. The expression level of sp-PIP was 250 mg/L in 10 L fermentor. Recombinant human insulin was obtained by means of transpeptidation of PIP or sp-PIP. The receptor binding capacity is identical with that of porcine insulin. In vivo biological activity of the recombinant human insulin is 27 IU/mg.

Journal Article↗