Intestinal flora translocation and overgrowth in upper gastrointestinal tract induced by hepatic failure

AIM: To explore the relationship between endoinfection caused by intestinal flora translocation and multiple organ dysfunction in hepatic failure.

METHODS: By using the quantitative bacteria culture, bacteria colony was counted in GI tract, bile duct and mesenteric lymphonodus in rat hepatic failure model.

RESULTS: Intestinal flora migrated up to the upper GI tract and overgrew in stomach and jejunum in rats with hepatic failure. The number of bacteria colonies in the specimens of stomach, jejunum and ileum were 4.7 × 10⁴/m L, 2.1 × 10⁵/mL, 5.5 × 10⁶/mL in experiment group and 4.6 × 10²/mL, 6.1 × 10¹/mL, 2.4 × 10³/mL in control group respectively (P < 0.05). Bacteria in bile duct and mesenteric lymphonodus of hepatic failure rats were also cultured. Extensive damages of gastrointestinal mucosa caused by bacterial overgrowth were observed.

CONCLUSION: Intestinal flora translocation and overgrowth in stomach and jejunum formed an endoinfectious source and caused obvious pathologic al injury of gastrointestinal mucosa, which play a very important role in developing abdominal distension, toxic intestinal expansion, alimentary tract haemorrh age and endotoxemia in patients with hepatic failure.

Study on liver targeting and hepatocytes permeable valaciclovir polybutylcyanoacrylate nanoparticles

AIM: To prepare valaciclovir polybutylcyan-oacrylate nanopa rticles (VACV-PBCA-NP) with liver targeting and hepatocyte permeable characteristics.

METHODS: Emulsion polymerization method was employed to prepare VACV-PBCA-NP. The formula and preparation conditions were optimized by using the uniform design. The organ distribution of the intravenously injected VACV-P BCA-NP and VACV in animal was determined using HPLC. The hepatocytes permeability of VACV-PBCA-NP was demonstrated by cell uptake experiment in vitro.

RESULTS: The drug loading and the drug embedding ratio of VACV-PBCA-NP were 11.20% and 84.85% respectively, with an average diameter of 104.77 nm ± 11.78 nm. The releasing characteristics in vitro fitted the two-phase kinetics. 74.49% of the drug was found to localize in the liver 15 min after the administration of VACV-PBCA-NP in the mice. Compared with VACV, VACV-PBCA-NP showed distinct characteristic of sustained-release in vivo and the drug entering hepatocytes were also greatly increased.

CONCLUSION: VACV-PBCA-NP has the characteristic of liver targeting and can increase the permeability of VACV to hepatocytes.

Telomerase activity in gastric cancer and its clinical implications

AIM: To study the telomerase expression in gastric carcinoma and its clinical implications.

METHODS: Telomerase activity was examined in gastric cancer an d corresponding normal tissues using a modified TRAP (telomeric repeat amplification protocol) assay (TRAP-eze) in tissue samples from 94 gastric carcinomas an d 58 normal tissues, 12 gastric adenomas and 9 gastric ulcer lesions.

RESULTS: Telomerase activity was present in 81 of the 94 (86.2%) gastric cancer tissues, whereas no telomerase activity was detected in any normal tissues. The incidence of telomerase activity in gastric cancer tissues was unrelated to the tumor diameter, histological grade, tumor invasion in depth, lymph node metastasis and TNM stage.

CONCLUSION: Telomerase plays an important role in carcinogenes is and progression of gastric cancer, and it is suggested to be a useful tumor marker.

Nitric oxide synthase distribution in esophageal mucosa and hemodynamic changes in rats with cirrhosis

AIM: To observe the nitric oxide synthase (NOS) distribution in the esophageal mucosa and hemodynamic changes in cirrhotic rats.

METHODS: NOS distribution in the lower esophagus of rats with carbon tetrachloride-induced cirrhosis was assessed by using NADPH-diaphorase (NADPH-d) histochemical method. Concentration of NO in serum were measured by fluorometric assay. Mean arterial pressure (MAP), cardiac output (CO), cardiac index (CI), splanchnic vascular resistance (SVR), and splanchnic blood flow (SBF) were also determined using ⁵⁷Co-labled microsphere technique.

RESULTS: Intensity of NOS staining in the esophageal epithelium of cirrhotic rats was significantly stronger than that in controls. There was a NOS-positive staining area in the endothelia of esophageal submucosal vessels of cirrhotic rats, but the NOS staining was negative in normal rats. NO concentration of serum in cirrhotic rats were significantly higher in comparison with that of controls. Cirrhotic rats had significantly lower MAP, SVR and higher SBF than those of the controls.

CONCLUSION: Splanchnic hyperdynamic circulatory state was observed in rats with cirrhosis. The endogenous NO may play an important role in development of esophageal varices and in changes of hemodynamics in cirrhosis.

Down-regulation of Hsp90 could change cell cycle distribution and increase drug sensitivity of tumor cells

AIM: To construct Hsp90 antisense RNA eukaryotic expression vector, transfect it into SGC7901 and SGC7901/VCR of MDR-type human gastric cancer cell lines, HCC7402 of human hepatic cancer and Ec109 of human esophageal cancer cell lines, and to study the cell cycle distribution of the gene transected cells and their response to chemotherapeutic drugs.

METHODS: A 1.03 kb cDNA sequence of Hsp90β was obtained from the primary plasmid phHSP90 by EcoRI and BamHI nuclease diges tion and was cloned to the EcoRI and BamHI site of the pcDNA by T4DNA ligase and an antisense orientation of Hsp90β expression vector was constructed. The constructs were transfected with lipofectamine and positive clones were selected with G418. The expression of RNA was determined with dot blotting and RNase protecti on assay, and the expression of Hsp90 protein determined with western blot. Cell cycle distribution of the transfectants was analyzed with flow cytometry, and the drug sensitivity of the transfectants to Adriamycin (ADR), vincrinstine (VCR), mitomycin (MMC ) and cyclophosphamide (CTX) with MTT and intracellular drug concentration of the transfectants was determined with flow cytometry.

RESULTS: In EcoRI and BamHI restriction analysis, the size and the direction of the cloned sequence of Hsp90β remained what had been designed and the gene constructs were named pcDNA-Hsp90. AH-SGC790, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones all expressed Hsp90 anti-sense RNA. The expression of Hsp90 was down-regulated in AH-SGC7901, AH SGC7901/VCR, AH-HCC7402 and AH-Ec109 cell clones. Cell cycle distribution was changed differently. In AH-SGC7901/VCR and AH-Ec109 cells, G₁ phase cells were increased; S phase and G₂ phase cells were decreased as compared with their parental cell lines. In AH-SGC7901 cell, G₁ phase cells were decreased, G₂ phase cells increased and S phase cells were not changed, and in AH-HCC7402 cells G₁, S and G₂ phase cells remai ned unchanged as compared with their parental cell lines. The sensitivity of AH SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 to chemotherapeutic drugs, the sensitivity of AH-SGC7901/VCR to ADR, VCR, MMC and CTX the sensitivity of AH-HCC7402 to ADR and VCR, and the sensitivity of Ec109 to ADR, VCR and CTX all increased as compared with their parental cell lines. The mean fluorescence intensity of ADR in AH-SGC7901, AH-SGC7901/VCR, AH-HCC7402 and AH-Ec109 was also significantly elevated (P < 0.05).

CONCLUSION: Down-regulation of Hsp90 could change cell cycle distribution and increase the drug sensitivity of tumor cells.

Effect of apolipoprotein E gene Hha I restricting fragment length polymorphism on serum lipids in cholecystolithiasis

AIM: To investigate the role of apolipoprotein E (apoE) polymorphism in the lithogenesis of gallstone and the hereditary pathogenesis of the disease.

METHODS: Polymerase chain reaction (PCR) was used to study apoE phenotypes and allele frequencies in patients with gallstones and control, and the fasting serum lipids of subjects were also measured by enzymatic methods.

RESULTS: The levels of triglyceride (TG) and very low density lipoprotein cholesterol (VLDL-C) were much higher in E_2/3 patients than that in E_2/3 control. E_3/3 patients were accompanied with remarkably low levels of high density lipoprotein cholesterol(HDL-C) and its subforms. But in E_3/4 patients there were only slight changes in levels of VLDL-C and low density lipoprotein cholesterol (LDL-C).

CONCLUSION: Different apoE phenotype patients with gallstones have different cheracteristics of dyslipidemia and the average level of serum lipids in patients with gallstones are higher than subjects without gallstones in the same apoE gene phenotype. ε2 allele is possibly one of the dangerous factors in the lithogenesis of chole-cystolithiasis.

Cloning and identification of an angiostatic molecule IP-10/crg-2

AIM: To obtain human and murine cDNAs encoding IFN-γ 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-γ and TNF-α , 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 306 bp and 314 bp inserts were established for further research on biological activities and ligands of hIP-10/mCrg-2

Studies on the flow and distribution of leukocytes in mesentery microcirculation of rats

AIM: To study the effect of leukocyte-endothelium interaction (LEI) on the flow and distribution of leukocytes in microcirculation under physiological condition.

METHODS: A microcirculation image multiple parameter computer analysis system (MIMPCAS) was used to study the flow and distribution of leukocytes in mesentery microcirculation of rats in vivo.

RESULTS: The difference of visible leukocyte flux (VLF) was as high as 131 times in the arterioles and venules with similar diameter and blood velocity. The visible leukocytes rolled along the blood vessel wall as a “jerky” movement. The frequency distribution of the visible leukocyte velocity (VLV) showed a “two-peak” curve. The low peak value was on 10 μm/s-15 μm/s while the high peak fell between 25 μm/s-30 μm/s. With the increase of diameter of venules, VLF increased while the VLV remained at the same level. With the increase of RBC velocity, VLV trends to elevate and VLF to fall down.

CONCLUSION: The results herein might provide a basic theory for the study on the mechanism of LEI under physiological condition and novel methods for the prevention and treatment of high LEI in many pathological processes.

Expression of perforin and granzyme B mRNA in judgement of immunosuppressive effect in rat liver transplantation

AIM: To explore the expression of perforin and granzyme B genes mRNA to judge the effect of immunosuppression in acute rejection of liver transplantation.

METHODS: The expression of perforin and granzyme B genes mRNA was examined by reverse transcription-polymerase chain reaction (RT-PCR) in hamster to rat liver grafts under the immunosuppression of cyclosporine or/and splenectomy. Histological findings were studied comparatively.

RESULTS: Cyclosporine could obviously decrease the cellular infiltration, and completely repress the expression of mRNA for perforin and granzyme B, but could not change severe hepatocyte necrosis and hemorrhage. Splenectomy could significantly lighten hepatocyte necrosis, and completely eliminate hemorrhage, but not affect the cellular infiltration and the expression of perforin and granzyme B genes mRNA. Cyclosporine or splenectomy alone could not prolong the survival time, however, their combination could completely repress the rejection of liver grafts. The survival time of animals were significantly prolonged (37.1 days). The architecture of hepatic lobules was preserved. There wes slight cellular infiltration in the portal tracts and no expression of perforin and granzyme B genes mRNA could been seen in three weeks after transplantation.

CONCLUSION: Perforin and granzyme B genes are valuable in judging the effect of immunosuppression in liver transplantation.

CT arterial portography and CT hepatic arteriography in detection of micro liver cancer

AIM: To recognize the characteristic findings of micro-liver cancer (MLC) and to evaluate the effect of CT arterial portography (CTAP) and CT hepatic arteriography (CTHA) in diagnosis of MLC.

METHODS: Between April 1996 to December 1998, CTAP and CTHA were performed in 12 patients with MLC, which were not detected by conventional CT examinations. After CTHA, 3 mL-5 mL mixture of lipiodol, doxorubicin and mitoycin C were injected into hepatic artery through the catheter, and the followed up by CT three or four weeks later (Lipiodol CT Lp-CT).

RESULTS: A total of 22 micro-tumors (0.2 cm-0.6 cm in diameter) were detected in 12 patients, which manifested as small perfusion defects in CTAP and small round enhancement in CTHA. The rate of detectability of CTAP and CTHA was 68.2% (15/22) and 77.3% (17/22) respectively, and the rate of the simultaneous use of both procedures reached 86.4% (19/22). All micro-tumors were demonstrated as punctate lipiodol deposit foci in Lp-CT. After Lp-CT, the elevated serum level of α-fetoprotein (AFP) dropped to the normal level in all patients.

CONCLUSION: The CTAP and CTHA are the most sensitive imaging methods for detecting micro-liver cancer. Confirmed by the change of the elevated serum AFP level and lipiodol deposit foci in Lp-CT, small perfusion defects in CTAP and puntuate enhancement in CTHA may suggest micro-liver cancer.

Pathogenic effects of Opolysaccharide from Shigella flexneri strain

AIM: To investigate the specific pathogenesis of O-polysaccharide (O-PS) which is on the outer membrane of lipopolysaccharides (LPS) from Shigella flexneri.

METHODS: The O-PS was isolated and purified from Shigella flexneri-5 M90T by enzymatic hydrolysis and gel chromatography. Effects of O-PS were observed by in vitro experiment, (HeLa cell culture), and in vivo experiment (rabbit ileal loop assay).

RESULTS: In vitro and in vivo experiments with the purified O-PS from Shigella flexneri-revealed that the O-PS alone was toxic to Hela cells and caused mucosal inflammation and hemorrhagic exudation in ileal loop of rabbit.

DISCUSSION: O-PS might be one of the factors causing diarrhea and its mechanism was different from endotoxin reaction of LPS. The molecular mechanism of O-PS need further studies.

Cyclosporin A protects Balb/c mice from liver damage induced by superan tigen SEB and D-GalN

AIM: To investigate the pathogenic effect of SEB and D-GalN on liver and the protection of cyclosporin A, the relationship between hepatic apoptosis and necrosis and the possible mechanism of acute hepatic necrosis.

METHODS: After staphylococcal enterotoxin B (SEB) mixed with D-galactosamine (D-GalN) were injected intraperitoneally into Balb/c mice and those previously treated with cyclosporin A, blood samples were collected and livers were isolated at 2, 6, 12, 24h. Patterns of hepatocellular death were studied morphologically and biochemically, circulating cytokines (TNF-α, IFN-γ) and mice mortality within 24h was assessed.

RESULTS: The SEB could induce the typical apoptotic changes of hepatocytes, the D-GalN could induce hepatocytes apoptosis and degeneration at the same time, and the mice having received the SEB + D-GalN injections developed apoptosis at 2 and 6h, but after 12h hepatocytes were characterized by severe injury, whereas all the examinations in the cyclosporin A treated mice were normal.

CONCLUSION: Hepatic cell apoptosis might be related to necrosis, and massive hepatocyte apoptosis is likely the initiating step of acute hepatic necrosis in mice. The effects induced by SEB and D-GalN on hepatocytes might be mediated by T cells, and could be prevented by cyclosporin A.

Cultivation of human liver cell lines with microcarriers acting as biological materials of bioartificial liver

AIM: To improve the cultivation efficiency and yield of human liver cell line Cl^-1.

METHODS: High-density cultivation of Cl^-1 on microcarriers was carried out with periodic observation of their growth and proliferation. The specific functions of human liver cell were also determined.

RESULTS: Cells of Cl^-1 cell line grew well on microcarrier Cytodex-3 and on the 7th day the peak was reached. The amount of Cl^-1 cells was 2.13 × 10⁸ and the total amount of albumin synthesis reached 71.23 μg, urea synthesis 23.32 mg and diazepam transformation 619.7 μg respectively. The yield of Cl^-1 on microcarriers was 49.3 times that of conventional cultivation. The amounts of albumin synthesis, urea synthesis and diazepam transformation were 39.8 times, 41.6 times and 33.3 times those of conventional cultivation, respectively.

CONCLUSION: The human liver cell line Cl^-1 can be cultivated to a high density with Cytodex-3 and has better biological functions. High-density cultivation of Cl^-1 on microcarriers can act as the biological material of bioartificial liver.

Study on the quality of recombinant proteins using matrix-assisted laser desorption ionization time of flight mass spectrometry

AIM:To study the possibility of matrix-assisted laser esorption/ionization time of flight mass spectrometry (MALDI-TOF MS) for controlling the quality of recombinant proteins.METHODS:By using MALDI-TOF MS, the molecular weights and purity of recombinant bioactive proteins were analyzed.RESULTS:The molecular weights and purity were obtained in nine recombinant bioactive proteins, including interleukin 2,tumor necrosis factor alpha, granulocyte macrophage colony stimulating factor, interferon alpha2b, interferon alpha1, erythropoietin, calmodulin and its fragment, and neuronal nitric oxide synthase were obtained. MALDI-TOF MS was also used to assay specific proteins in the mixtures and to characterize the erythropoietin tryptic digests.CONCLUSION:The results showed that MALDI-TOF MS can be employed for the effective quality control of recombinant proteins.