Expression of growth hormone receptor and its mRNA in hepatic cirrhosis

AIM: To investigate the expression of growth hormone receptor (GHR) and mRNA of GHR in cirrhotic livers of rats with the intension to find the basis for application of recombinant human growth hormone (rhGH) to patients with liver cirrhosis.METHODS: Hepatic cirrhosis was induced in SpragueDawley rats by administration of thioacetamide intraperitoneally for 9-12 weeks. Collagenase Ⅳ was perfused in situ for isolation of hepatocytes. The expression of GHR and its mRNA in cirrhotic livers was studied with radio-ligand binding assay, RT-PCR and digital image analysis.RESULTS: One class of specific growth hormone-binding site, GHR, was detected in hepatocytes and hepatic tissue of cirrhotic livers. The binding capacity of GHR (RT, fmol/mg protein) in rat cirrhotic liver tissue (30.8±1.9) was significantly lower than that in normal control (74.9±3.9) at the time point of the ninth week after initiation of induction of cirrhosis (n=10, P＜0.05), and it decreased gradually along with the accumulation of collagen in the process of formation and development of liver cirrhosis (P＜0.05). The number of binding sites (×10 4/cell) of GHR on rat cirrhotic hepatocytes (0.86±0.16) was significantly lower than that (1.28±0.24)in control (n= 10, P＜0.05). The binding affinity of GHR among liver tissue, hepatocytes of various groups had no significant difference (P＞0.05). The expression of GHR mRNA (riOD,pixel) in rat cirrhotic hepatic tissues (23.3±3.1) was also significantly lower than that (29.3±3.4) in normal control (n=10, P＜0.05).CONCLUSION: The growth hormone receptor was expressed in a reduced level in liver tissue of cirrhotic rats,and lesser expression of growth hormone receptors was found in a later stage of cirrhosis. The reduced expression of growth hormone receptor was partly due to its decreased expression on cirrhotic hepatocytes and the reduced expression of its mRNA in cirrhotic liver tissue.

Studies on Purification of Methamidophos Monoclonal Antibodies and Comparative Immunoactivity of Purified Antibodies

To purify Methamidophos (Met) monoclonal antibodies with two methods and compare immune activity of purified antibodies. Method Caprylic acid ammonium sulphate precipition (CAASP) method and Sepharose protein-A (SPA) affinity chromatography method were used to purify Met monoclonal antibodies, UV spectrum scanning was used to determine protein content and recovery of purified antibodies, sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze the purity of purified antibodies, and enzyme-linked immunosorbent assay (ELISA) was used to determine immune activity of purified antibodies. Results Antibody protein content and recovery rate with CAASP method were 7.62 mg/mL and 8.05% respectively, antibody protein content and recovery rate with SPA method were 6.45 mg/mL and 5.52% respectively. Purity of antibodies purified by SPA method was higher than that by CAASP method. The half-maximal inhibition concentration (IC50) of antibodies purified by SPA to Met was 181.26 靏/mL, and the linear working range and the limit of quantification (LOD) were 2.43-3896.01 靏/mL and 1.03 靏/mL, respectively. The IC50 of antibodies purified by CAASP to Met was 352.82 靏/mL, and the linear working range and LOD were 10.91-11412.29 靏/mL and 3.42 靏/mL, respectively. Conclusion Antibodies purified by SPA method are better than those by CAASP method, and Met monoclonal antibodies purified by SPA method can be used to prepare gold-labelled testing paper for analyzing Met residue in vegetable and drink water.

The Different Expression Pattern of E-cadherin and β-catenin in Primary Nasopharyngeal Carcinoma and Its Metastases

To detect the differences in the expression levels of protein and mRNA of E-cadherin and β-eatenin in primary tumor and lymph node metastatic tumor of nasopharyngeal carcinoma (NPC), and to investigate the mechanism of invasion and metastasis of neoplastic cell in NPC. Methods: 21 biopsies taken from primary tumor and another 21 biopsies from lymph node metastatic tumor of NPC were collected from the affiliated hospitals of Sun Yat-sen University of Medical Sciences during 1999 2002. Western blotting assay, immunohistoehemieal staining and reverse transeriptase-polymeraes chain reaction (RT-PCR) were adopted to detect the expression levels of protein and mRNA of E-eadherin and β-eatenin in all of 42 samples. Results: (1) In 21 eases of lymph node metastatic tumor, the protein expression level of E-eadherin was lower detected by immunohistoehemieal staining (50% in average) and Western blotting (Rh 65±15.9 in average) than that in primary tumor of NPC (80% and 206.7+32.7 in average respectively). Furthermore, mRNA expression level of E-eadherin was also lower in metastatic tumor than that in primary tumor, with the difference being significant (P<0.05). (2) Both primary NPC and lymph node metastatic NPC were found to have high β-eatenin protein and mRNA expression with the differences being not statistically significant (P>0.05). (3) There was no correlation between neoplastic cell expression of β-eatenin and E-eadherin either in primary tumor or in lymph node metastatic tumors. Conclusion: Down-regulation of the expression of E-eadherin may play a critical role in neoplastic cell invasion and metastasis in NPC.