Biomedical subjects

Zhen-Shu Zhang

Publications and source records attributed to Zhen-Shu Zhang.

10 recordsLinked to original sources

PubMed2004

Competitive inhibition of adherence of enterotoxigenic Escherichia coli, enteropathogenic Escherichia coli and Clostridium difficile to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027.

AIM: To observe competitive inhibition of adherence of enterotoxigenic Escherichia coli (ETEC), enteropathogenic Escherichia coli (EPEC) and Clostridium difficile (C. difficile) to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027 (B. ado 1027). METHODS: The binding of bacteria to intestinal epithelial cell line Lovo was counted by adhesion assay. The inhibition of adherence of ETEC, EPEC and C. difficile to intestinal epithelial cell line Lovo by purified adhesin of B. ado 1027 was evaluated quantitatively by flow cytometry. RESULTS: The purified adhesin at the concentration of 10 microg/mL, 20 microg/mL and 30 microg/mL except at 1 microg/mL and 5 microg/mL could inhibit significantly the adhesion of ETEC, EPEC and C. difficile to intestinal epithelial cell line Lovo. Moreover, we observed that a reduction in bacterial adhesion was occurred with increase in the concentration of adhesin, and MFI (Mean fluorescent intensity) was decreased with increase in the concentration of adhesin. CONCLUSION: The purified adhesin of B. ado 1027 can inhibit the adhesion of ETEC, EPEC and C. difficile to intestinal epithelial cell line Lovo in a dose-dependent manner.

Adhesins, Bacterial↗

PubMed2003

A new three-layer-funnel-shaped esophagogastric anastomosis for surgical treatment of esophageal carcinoma.

AIM: To reduce the incidence of postoperative anastomotic leak, stenosis, gastroesophageal reflux (GER) for patients with esophageal carcinoma, and to evaluate the conventional method of esophagectomy and esophagogastroplasty modified by a new three-layer-funnel-shaped (TLF) esophagogastric anastomotic suturing technique. METHODS: From January 1997 to October 1999, patients with clinical stage I and II (IIa and IIb) esophageal carcinoma, which met the enrollment criteria, were surgically treated by the new method (Group A) and by conventional operation (Group B). All the patients were followed at least for 6 months. Postoperative outcomes and complications were recorded and compared with the conventional method in the same hospitals and with that reported previously by McLarty et al in 1997 (Group C). RESULTS: 58 cases with stage I and II (IIa and IIb) esophageal carcinoma, including 38 males and 20 females aged from 34 to 78 (mean age: 57), were surgically treated by the TLF anastomosis and 64 by conventional method in our hospitals from January 1997 to October 1999. The quality of swallowing was improved significantly (Wilcoxon W=2 142, P=0.0 001) 2 to 3 months after the new operation in Group A. Only one patient had a blind anastomatic fistula diagnosed by barium swallow test 2 months but healed up 3 weeks later. Postoperative complications occurred in 25 (43 %) patients, anastomotic stenosis in 8 (14 %), and GER in 13 (22 %). The incidences of postoperative anastomotic leak, stenosis and GER were significantly decreased by the TLF anastomosis method compared with that of conventional methods (chi(2)=6.566, P=0.038; chi(2)=10.214, P=0.006; chi(2)=21.265, P=0.000). CONCLUSION: The new three-layer-funnel-shaped esophagogastric anastomosis (TLFEGA) has more advantages to reduce postoperative complications of anastomotic leak, stricture and GER.

Adult↗

PubMed2003

Comparing the base usage frequency between bacteria DNA double strand.

During the Evolution, effected by select pressure or nature mutation, the compositions of bacteria genomes is various. And many experiences prove that the genes between leading strand and lagging strand is distinctly in copy, transcription and repair. Some scholars presume that the bases distribution is difference between the two strand, to verify the guess, we using the technology of bioinformatics, compare the base usage between the DNA double strand in 17 species bacteria. The result show: 1. there is same bases usage frequency in coding sequence between leading strand and lagging strand 2. There also same bases usage frequency in first codon, second codon and third codon. It suggest that there is a equilibrium between the two strand by the effect of select pressure and nature mutation.

Bacteria↗

PubMed2002

[Expression and identification of phage display library for Fab fragments of colorectal cancer-related antibodies].

OBJECTIVE: To express the original human Fab antibody phage display library with positive recombined bacterium XL1-blue-Pcomb3 and identify its specific binding activity with colorectal cancer cells in vitro after screening with human colorectal cancer-related antigens. METHOD: The recombination rate of Fd fragment of the heavy chain and insertion of kappa chain of the antibodies was determined with PCR, and the original Fab library was expressed. The antigens were extracted from 3 sensitized colorectal cancer tissues previously used for construction of the original Fab library and from 13 non-sensitized colorectal cancer tissues, along with the antigens from LoVo, HT-29 and LS-174T cells cultured in vitro. The original Fab antibody library was screened with the 3 groups of mixed antigens derived in preceding procedure and 3 tertiary Fab antibody libraries were obtained, which were then mixed in equal volume for subsequent tests of binding activity with human colorectal cancer tissues and cells in vitro using enzyme-linked immunosorbent assay (ELISA) and immunohistochemical staining. Specimens of gastric and esophageal carcinomas and normal intestinal mucosa, together with liver cancer cells and gastric cancer cells were utilized as control. RESULT: The recombination rate of Fd and kappa chain were 40 % and 70 % respectively, and the rate of their simultaneous insertion into Pcomb3 vector was 28%. The capacity of library for Fab fragment genes was 2.1x10(6), and the original antibody libraries screened with the 3 groups of mixed antigens were enriched to varied degrees, which all displayed relatively specific binding activity with human colorectal cancer tissue and cells in vitro. CONCLUSION: Colorectal cancer-related antibody Fab fragments are obtained through screening phage display library, which show relatively specific binding activity with human colorectal cancer tissues and cells.

Antibodies, Neoplasm↗

PubMed2002

Effect of protein kinase C on multidrug resistance of multidrug-resistant colorectal cancer LoVo/Adr cells.

OBJECTIVE: To observe the effect of protein kinase C (PKC) on the multidrug resistance of multidrug-resistant colorectal cancer LoVo/Adr cells and explore the mechanism. METHODS: The changes of PKC activity in LoVo/Adr cells in response to treatment with staurosporine (SP) and phorbol-12-myristate-13-acetate (PMA) were detected by way of 32P incorporation. The effect of PKC on adriamycin uptake in LoVo/Adr cells was detected by flow cytometry. Reverse transcriptase-PCR was utilized to observe the effect of PKC on mdr1 gene expression. RESULTS: PMA evinced bi-directional regulation of PKC activity in LoVo/Adr cells, and SP significantly inhibited membrane and cytosol fraction of PKC activity. Preincubation with PMA for 30 min caused the uptake of adriamycin to decrease significantly, but when the preincubation was prolonged to 24 h, significant increase occurred in adriamycin uptake. Neither PMA nor SP, however, could affect the expression of mdr1 gene. CONCLUSION: PKC regulates multidrug resistance of the cells through mechanisms other than regulation of mRNA level of mdr1 gene.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

Detection of soluble tumor necrosis factor-p55 levels in the serum and ascitic fluid of patients with hepatocellular carcinoma.

OBJECTIVE: To examine soluble tumor necrosis factor receptor-p55 (sTNFR-p55) levels in the serum and ascitic fluid and investigate the significance of this examination in assessment of the clinical status of patients with primary hepatocellular carcinoma (HCC). METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to examine sTNFR-p55 levels in the serum and ascitic fluid in 25 patients with HCC and 25 with liver cirrhosis (LC). RESULTS: sTNFR-p55 levels in the serum and ascitic fluid in patients with HCC were significantly higher than those in patients with LC and controls (P=0.001). No significant difference was found between LC and the control in terms of serum sTNFR-p55 levels (P=0.19). Positive correlation was observed between sTNFR-p55 levels in the serum and in ascitic fluid of patients with HCC and LC (r=1.000, P<0.001). Logistic regression revealed that in patients with HCC, serum sTNFR-p55 levels were positively correlated with TBil and AFP in the peripheral blood (r=0.524, P=0.01 and r=0.234, P=0.03, respectively). CONCLUSIONS: Increased sTNFRs-p55 levels in the serum and ascitic fluid reflect abnormal immune status of the patients with HCC and help predict the development of tumor.

Adult↗

PubMed2002

[Effect of Helicobacter pylori infection on gastric mucosal cell proliferation in Mongolian gerbils].

OBJECTIVE: To explore the mechanism that Helicobacter pylori (H. pylori) infection can induce adenocarcinoma in Mongolian gerbil model with long-term H. pylori infection. METHODS: Mongolian gerbil model with long-term H. pylori infection was established by inoculation H. pylori NCTC 11637 strain, and immunohistochemical straining and in situ hybridization were employed to observe changes in gastric mucosal cell proliferation due to H. pylori infection. RESULTS: Mongolian gerbil model with long-term H. pylori infection was successfully established. Immunohistochemical staining of 5'-bromodeoxyuridine (BrdU) and proliferating cell nuclei antigen (PCNA) showed that H. pylori infection induced the increase in gastric mucosal cell proliferation (P<0.05), and in situ hybridization of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) revealed elevated expressions of EGF mRNA and EGFR mRNA with time passage after H. pylori infection (P<0.05). CONCLUSION: H. pylori inoculation can induce abnormality in gastric mucosal cell proliferation, which is instrumental for the progression from chronic gastritis to glandular atrophy, intestinal metaplasis and ultimately to atypical hyperplasia. The abnormal expressions of EGF and EGFR may be the key element for abnormality of gastric mucosal cell proliferation.

Animals↗

PubMed2002

[Uptake and distribution of adriamycin in multidrug-resistant LoVo/Adr cells].

OBJECTIVE: To investigate adriamycin (Adr) uptake and distribution features in multidrug-resistant LoVo/Adr cells and explore the drug-resistance mechanism of the cells. METHODS: Adr uptake in LoVo/Adr cells was observed by flow cytometry and the distribution of the drug examined by fluorescence microscope. Immunohistochemical method was employed to detect the expression of P-glycoprotein (P-gp) by the cells. RESULTS: In comparison with that in LoVo/Adr cells, Adr level in LoVo cells was significantly higher, but after treatment with verapamil, the former cells showed an increased Adr level. Adr distributed mainly in the nucleus in the drug-sensitive LoVo cells, with only a small quantity in the cytoplasm, while in multidrug-resistant LoVo/Adr cells, significantly reduction of Adr quantity in the nucleus and relative increase in the cytoplasm were observed. In response to verapamil treatment, the Adr uptake in LoVo/Adr cells increased and the distribution of the drug was similar to that in sensitive cells. P-gp expression was positive in LoVo/Adr cells, while negative in LoVo cells. CONCLUSION: Abnormal Adr uptake and distribution in drug-resistant cells is related to P-gp expression which is one of the mechanisms for multidrug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

[Endoscopic diagnosis and treatment of the early-stage malignant colorectal polyp and follow-up study].

In the past 20 years we have performed endoscopic removal of colorectal polyps in 4 000 cases, and thorough histological examination of the removed polyps identified 121 cases of early-stage malignant polyp. According to the depth of malignant invasion and whether malignant remnants were present after the initial surgical removal, conservative treatment or radical operation was implemented. During the follow-up study, endoscopy was performed once each year in all the patients with malignancies. No recurrence was found in the 33 patients with mucosa cancer or in the 27 patients with type I submucosa cancer who did not receive radical operation due to absence of malignant remnants or in the 38 patients with type II submucosa cancer who had the radical operation. Relapse occurred in 1 patient with malignant remnant and in another 3 cases of type II submucasa cancer without radical operation.

Adult↗

PubMed2002

[CPP32 expression and its significance in multidrug-resistant tumor cells and their parent cells].

OBJECTIVE: To study the expression difference of CPP32 in multidrug-resistant (mdr) tumor cells and their parent cells and to understand the possible effect of CPP32 in apoptosis induction in the 2 cell lines. METHODS: Sequence analysis of CPP32 mRNA extracted form mdr gastric cancer cell line SGC7901/VCR08 and naive cell line SGC7901 was performed by means of reverse transcriptase-polymerase chain reaction (RT-PCR), and the protein expression of CPP32 in the 2 cell lines assayed by way of Western blotting. RESULTS: The expressions of CPP32 mRNA was comparable in the 2 cell lines, and sequence analysis found consistent sequence of CPP32 in both cell lines with previous report. No differences was identified in the protein expression, either. CONCLUSION: The apoptosis resistance of mdr cells is not related to the abnormality of CPP32 but the upstream of caspase, the fact of which indicates promising prospect of the research on reversion of mdr cells using CPP32 as target.

Apoptosis↗