Biomedical subjects

Ying Han

Publications and source records attributed to Ying Han.

83 records · Page 5Linked to original sources

PubMed2002

Toward synthetic transcription activators: recruitment of transcription factors to DNA by a PNA-peptide chimera.

A PNA-peptide chimera designed to mimic the biochemical function of transcription activators has been synthesized and characterized. The bis-PNA segment binds specifically to a DNA site while the 20-residue peptide is capable of binding to the transcription factors Gal11 and Gal80. The PNA-peptide chimera thus mimics one of the central functions of a native transcription activator, recruitment of transcription factors to a specific DNA site.

DNA↗

PubMed2002

Bioequivalence of clavulanate potassium and amoxicillin (1:7) dispersible tablets in healthy volunteers.

To study the bioequivalence of Clavulanate Potassium and Amoxicillin (1:7) dispersible tablets, a randomized cross-over study was conducted in 18 healthy volunteers. A single oral dose of 1,000 mg Clavulanate Potassium and Amoxicillin (1:7) dispersible tablets (Tested formulation, T) or Augmentin syrup (Reference formulation, R). Concentrations in plasma were determined with high-performance liquid chromatography. The main parameters of T were: for Clavulanate Potassium and Amoxicillin, Cmax: 2.46 +/- 1.11 micrograms/ml and 18.81 +/- 7.26 micrograms/ml, Tmax: 1.12 +/- 0.23 h and 1.30 +/- 0.34 h, AUC(0-6 h): 5.18 +/- 2.24 micrograms.h/ml and 45.09 +/- 14.53 micrograms.h/ml, t1/2: 1.43 +/- 0.44 h and 1.09 +/- 0.22 h., respectively. The relative bioavailability of T to R were 96.5 +/- 19.2% and 98.4 +/- 26.1%, respectively. Statistical analysis showed that the two formulations were bioequivalent.

Adult↗

PubMed2002

MGr1-Ag is associated with multidrug-resistant phenotype of gastric cancer cells.

BACKGROUND: MGr1-antigen (Ag) was previously reported as an upregulated protein in multidrug-resistant (MDR) gastric cancer cells. The aim of this study was to characterize the role of MGr1-Ag in the multidrug resistance of gastric cancer cells. METHODS: Laser scanning confocal microscopy (LSCM), two-dimensional electrophoresis, and Western blot were used to detect MGr1-Ag in gastric cancer cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to determine the sensitivity of the MDR gastric cancer cells, SGC7901/VCR, to chemotherapeutic drugs. Adriamycin accumulation and retention in SGC7901/VCR cells were analyzed using flow cytometry. RESULTS: LSCM showed that MGr1-Ag localized mainly on the membrane and partly in the cytoplasm of SGC7901/VCR cells. Western blot showed that the expression level of MGr1-Ag in SGC7901/VCR cells was higher than that in its parental cells, SGC7901, and that the apparent molecular weight and isoelectric point of MGr1-Ag were 42 kDa and pH 4.8, respectively. After incubation with MGr1 antibody, SGC7901/VCR cells showed significantly decreased IC(50) values for adriamycin (from 0.887 +/- 0.081 mg/l to 0.607 +/- 0.084 mg/l; P, 0.05), vincristine (from 0.707 +/- 0.055 mg/l to 0.557 +/- 0.042 mg/l; P, 0.05), and 5-fluorouracil (from 4.367 +/- 0.407 mg/l to 2.630 +/- 0.644 mg/l; P, 0.05), as well as slightly increased IC(50) values for mitomycin (from 0.183 +/- 0.045 mg/l to 0.198 +/- 0.048 mg/l; P. 0.05). In addition, incubation with MGr1 significantly enhanced adriamycin accumulation and retention in SGC7901/VCR cells. CONCLUSION: Overexpression of MGr1-Ag is associated with the MDR phenotype of gastric cancer cells.

Antibodies, Monoclonal↗

PubMed2002

Expression and function of classical protein kinase C isoenzymes in gastric cancer cell line and its drug-resistant sublines.

AIM: To investigate the expression and function of classical protein kinase C (PKC) isoenzymes in inducing MDR phenotype in gastric cancer cells. METHODS: Two cell lines were used in the study: gastric cancer cell SGC7901 and its drug-resistant cell SGC7901/VCR stepwise-selected by vincristine 0.3, 0.7 and 1.0 mg.L(-1), respectively. The expression of classical PKC (cPKC) isoenzymes in SGC7901 cells and SGC7901/VCR cells were detected using immunofluorescent cytochemistry, laser confocal scanning microscope and Western blot. The effects of anti-PKC isoenzymes antibody on adriamycin accumulation in SGC7901/VCR cells were determined using flow cytometric analysis. RESULTS: (1)SGC7901 cells exhibited positive staining of PKC-alpha. SGC7901/VCR cells exhibited stronger staining of PKC-alpha than SGC7901 cells. The higher dosage vincristine selected, the much stronger staining of PKC-alpha was observed on SGC7901/VCR cells. (2)Both SGC7901 and SGC7901/VCR cells exhibited positive staining of PKC-beta I and PKC-beta II with no significant difference. (3) Compared with SGC7901, SGC7901/VCR cells had decreased adriamycin accumulation and retention. Accumulation of adriamycin in SGC7901 was 5.21+/-2.56 mg.L(-1),in SGC7901/VCR 0.3 was 0.85+/-0.29 mg.L(-1), in SGC7901/VCR 0.7 was 0.81+/-0.32 mg.L(-1), and in SGC7901/VCR 1.0 was 0.80+/-0.33 mg.L(-1); Retention of adriamycin in SGC 7901 was 2.51+/-1.23 mg.L(-1), in SGC7901/VCR 0.3 was 0.47+/-0.14 mg.L(-1), in SGC7901/VCR 0.7 was 0.44+/-0.15 mg.L(-1), and in SGC 7901/VCR 1.0 was 0.41+/-0.11 mg.L(-1). (4) Fluorescence intensity presented adriamycin accumulation in SGC7901/VCR cells was increased from 1.14+/-0.36 to 2.71+/-0.94 when cells were co-incubated with anti-PKC-alpha but not with anti-PKC-beta I PKC-beta II and PKCgamma antibodies. CONCLUSION: PKC-alpha, but not PKC-beta I, PKC-beta II or PKCgamma, may play a role in multidrug resistance of gastric cancer cells SGC7901/VCR.

Antineoplastic Agents, Phytogenic↗

PubMed2002

[Expression of Fas genes transduced into colorectal cancer cells].

OBJECTIVE: To construct colorectal cancer cells expressing exogenous Fas gene and observe the expression level of its mRNA and protein before and after transduction. METHODS: Fas cDNA was inserted into the multiple cloning site of the expression vector pBK-CMV with molecular cloning technique, and the resultant recombinant plasmid was transduced into colorectal cancer LoVo cells via lipofectamine. G418 was utilized to screen the positive clones containing the recombinant plasmid, where Fas mRNA and protein expression was determined with Western blotting and dot blotting. RESULTS: pBK-CMV Fas cDNA plasmid was successfully constructed. The transduced colorectal cancer cells were screened by G418 and a resistant cell line (LoVo Fas cells) was obtained. Fas expression was detected in both transduced and non-transducted cell lines, but the expression level of both Fas mRNA and protein was much higher in the former, which showed lowered proliferation rate and lengthened doubling time and logarithm growth period than the non-transducted cells, but the difference was not significant. Treatment of the transduced cells with Fas antibody produced significant difference (P<0.05), manifested by apparently inhibited cell growth. CONCLUSIONS: LoVo cells normally has only very low expression level of Fas gene, while transduction with pBK-Fas cDNA can enhance the efficiency of Fas mRNA and protein expressions. Fas antibody significantly inhibits the growth and proliferation of in vitro cultured Fas-expressing LoVo cells.

Colorectal Neoplasms↗

PubMed2002

[Studies on blood viscosity and external thrombus in patients with silicosis and silicosis complicated with tuberculosis].

OBJECTIVE: To explore the changes of blood viscosity and external thrombus in patients with silicosis and silicosis complicated with tuberculosis (TB). METHOD: Blood viscosity and external thrombus were measured in 288 patients with silicosis, 178 patients with silicosis complicated by TB and 150 healthy subjects. RESULTS: Blood viscosity and external thrombus value were significantly higher in the patients of silicosis and silicosis complicated with TB than in the healthy controls, except for patients of phase I of silicosis. Blood viscosity in the silicotics increased significantly with the advance of the disease, but no significant difference in external thrombus between patients in different phases. Apparent viscosity of whole blood significantly increased in the high-shear rate (200 s(-1)) and middle-shear rate (30 s(-1)) in patients of silicosis complicated with TB than in those without complication of TB at the same phases, but not seen in the low-shear rate (5 s(-1)) and in plasma viscosity, and the length and dried weight of external thrombus increased significantly too. There was no significant difference in blood viscosity and external thrombus between patients of silicosis at phase III and those of silicosis complicated with TB at the same phase. CONCLUSION: Blood in patients with silicosis appeared highly viscous and highly coagulant status. Blood viscosity and external thrombus value significantly increased with the advance of the disease, especially in the patients complicated with TB.

Adult↗

PubMed2002

[Delayed rectifier K(+) channel regulated by cyclooxygenase-2 in human gastric cancer cell].

OBJECTIVE: To correlate delayed rectifier K(+) channel to cyclooxygenase-2 (COX-2) in onco genesis of human gastric cancer cell. METHODS: Human COX-2 encoding gene was cloned with RT-PCR strategy and its antisense recombinant eukaryotic expression vector was constructed. COX-2 highly expressed human gastric cancer cell line SGC7901 was stably transfected with the antisense vector. The whole-cell recording technique of perforated patch clamp was employed to observe the change of delayed rectifier K(+) current (I(k)) of SGC7901 after gene transfer or treatment with COX-2 inhibitor indomethacin. MTT was also performed to determine the effect of delayed rectifier K(+) channel inhibitors on cell growth. RESULTS: Stably transfected cell (7901-AS) was obtained and a down-regulated expression of COX-2 protein and mRNA in the cell was achieved. Patch clamp recording showed that both SGC7901 and 7901-AS cells had a typical delayed rectifier K(+) current. However, I(k) was significantly lower (P < 0.01) in transfected cell or cell treated with indomethacin at each test potential. The altered I(k) could be entirely recovered after drug removal from the cells. K(+) channel blockers tetraethylammonium (TEA) and 4-aminopyridine (4-AP) could retard the growth of SGC7901 and the transfected cell in a dose-dependent manner. CONCLUSION: Delayed rectifier K(+) channel, existing in human gastric cancer cell line SGC7901, is related to the growth of the cell. The highly expressed COX-2 may affect the biological behavior of gastric cancer cell by regulating this ion channel.

Cell Division↗

PubMed2002

[New tactics of human red blood cells stored at 4 degrees C-protective effect of antioxidant solution on red blood cells damage].

Aliquots of venous blood from healthy donor were collected in plastic blood storage bags with ACD, GMA or antioxidant solution (superoxide dismutase, SOD), respectively, and stored at 4 degrees C. After storage for varying periods, the parameters of the blood were detected in the blood samples. Results showed that the parameters of the blood stored at 4 degrees C for 75 days in SOD group were following: the recovery of RBC-Hb was 87.2%, plasma-Hb (mg/L) was 193.2, P50 (mmHg) was 34.0 (normal value was 33.1); deformability (DImax) was 0.2413 (74.3% of normal value). There was no evident hemolysis, color change, air bubble and clots. It was concluded that human RBC stored at 4 degrees C for 75 days with SOD solution, recovery of levels of RBC-Hb and plasma-Hb were accorded with the requirements of "Basic Demands of Blood Station" in China.

Antioxidants↗

PubMed2002

[Determination of lead and cadmium contents in toilet paper].

Contents of pollutant elements lead and cadmium in toilet paper were determined by atomic absorption spectrometry. Both lead and cadmium has good linear relationship that lead is over the range of 0.00-10.00 micrograms.mL-1 (r = 0.9989) and cadmium is over the range of 0.00-4.00 micrograms.mL-1 (r = 0.9997). In this method, RSD is bellow 3.08% and recovery is over the range of 94.8%-104.5%. The method is simple and accurate. It can be used as monitor method of lead and cadmium in toilet paper.

Cadmium↗

PubMed2000

Does flexible small-diameter colonoscope reduce insertion pain during colonoscopy?

AIM:It is well known that colonoscopy can be difficult due to abdominal pain induced during colonoscope insertion, if sedative agents are not given. Recently, an extra-flexible, small-diameter colonoscope (CF-SV, Olympus Inc.Japan) was developed in order to improve safety and comfort. The aim of this study was to access the usefulness of the CF-SV.METHODS:One hundred patients undergoing sigmoidoscopy were recruited and colonoscopy was performed by one experienced colonoscopist. First, a routine type colonoscope (CF-230I) was inserted into the colon without sedation. When the patient complained of abdominal pain (even if mild), the scope was not advanced further and was withdrawn after the anatomic location of its tip was determined fluoroscopically. Then, the CF-SV was inserted until it reached the cecun or the site where abdominal pain occurred. Previous abdominal surgery and abdominal disease were considered as unfavorable factors (UF) and the relationship between abdominal pain and UF, age and gender were investigated.Furthermore, the colonic insertion pressures in 36 patients with abdominal pain were measured with a force gauge.RESULTS:Thirty-four cases (34%) felt no pain with the CF-230I and successful pancolon-oscopies to the cecum were performed. Sixty-six cases (66%) complained of abdominal pain. The procedure was painless for 47% of men and 24% of women, respectively. The CF-230I scope failed to reach the sigmoid-descending colon junctions in 59 (89.4%) of the 66 patients complaining of abdominal pain. However, CF-SV reached proximal area in 94.9% of those who failed with CF-230I. The median pressure for pain-inducing was 700g/cm(2).CONCLUSION:Unsedated patients with UF were prone to complain of pain when the standard type CF-230I scope was used. The newly developed extra-flexible CF-SV is useful for the aged and for those with UF or being prone to suffer from abdominal pain. Sedative agents may be unnecessary if this new type of colonoscope is used.

Journal Article↗

PubMed1999

Cloning and identification of an angiostatic molecule IP10/crg -2.

AIM:To obtain human and murine cDNAs encoding IFN-gamma inducible protein 10 (IP-10) and cytokine responsive gene-2 (Crg-2).METHODS:The encoding genes of IP-10 and Crg-2 were amplified by RT-PCR from cultured human fibroblast cells and Balb/c mouse liver treated by IFN-gamma and TNF-alpha,respectively, and cloned into plasmids of pUC19 and pGEM3Zf(+).RESULTS:The nucleotide sequences of the amplified DNA were confirmed by endonucleases digestion and sequencing.CONCLUSION:Recombinant IP-10/crg-2 gene clones with 306bp and 314bp inserts were established for further research on biological activities and ligands of hIP-10/mCrg-2.

Journal Article↗