AIM: To establish a model of drug-resistant neoplasms using a nude mice model, orthotopic transplantation of liver neoplasm and sporadic abdominal chemotherapy. METHODS: Hepatocellular carcinoma cells HepG2 were cultu...AIM: To establish a model of drug-resistant neoplasms using a nude mice model, orthotopic transplantation of liver neoplasm and sporadic abdominal chemotherapy. METHODS: Hepatocellular carcinoma cells HepG2 were cultured and injected subdermally to form the tumor-supplying mice. The orthotopic drug-resistant tumors were formed by implanting the tumor bits under the envelope of the mice liver and induced by abdominal chemotherapy with Pharmorubicin. Physical examination, ultrasonography, spiral CT and visual inspection were used to examine tumor progression. RT-PCR and immunohistochemistry were used to detect expression of mdr1 mRNA and its encoded protein p-glycoprotein (p-gp). Tc-99m sestamibi scintigraphy was performed by obtaining planar abdominal images at 20 min after injection, and the liver/heart ratios were calculated. RESULTS: Post-implantation mortality was 0% (0/25), tumor implantation success was 90% (22/25), and the rate of implanting successfully for the second time was 100% (3/3). Tumor induction using Pharmorubicin was 80% (16/20). The mdrl mRNA expression of the induced group was 23 times higher than that of the control group, and p-gp protein expression was 13-fold higher compared to the control group. The liver/heart ratio (as assessed in vivo, using Tc-99m radiography) was decreased significantly in the induced group as compared to the control group. CONCLUSION: We have established an in vivo model of mdrl in nude mice by orthotopic transplantation of liver neoplasm coupled to chemotherapy. We propose that identification of drug resistance as characterized by decreased 99mTc-ppm radiography due to enhanced clearance by p-gp may be useful in detecting in vivo drug resistance, as well as a useful tool in designing more effective therapies.展开更多
A series of experiments based on electrophoretical and biochemical assays were conducted to partially characterize proteinases present in the hepatopancreas and intestine of black carp （Mylopharyngodon piceus）, a...A series of experiments based on electrophoretical and biochemical assays were conducted to partially characterize proteinases present in the hepatopancreas and intestine of black carp （Mylopharyngodon piceus）, and investigate enzymatic activity and protein digestibility in vitro. Casein digestion assays revealed the presence of acidic proteinases with optimum activity in the range of pH 2.0-2.5 and alkaline proteinases with significantly higher activities both in the range of pH 8.1-8.6 and near pH 9.5. The inhibition and substrate specificity assays showed that trypsin and chymotrypsin are the main active components of the alkaline proteinases. The SDS-substrate-PAGE showed that the crude extract of black carp intestine had eight types of alkaline proteinases with the molecular mass range of 27.5-78.5 kDa while the crude extract of black carp hepatopancreas had six types of alkaline proteinases with the molecular mass range of 27.5-78.5 kDa. These enzymes were characterized as trypsin （27.5 kDa, 30.1 kDa）, chymotrypsin （40.5 kDa, 42.5 kDa）, serine proteinases （32.1 kDa, 33.2 kDa） and non-serine proteinase （61.5 kDa, 78.5 kDa）.In vitro protein digestibility assays showed that black cardcan be able to utilize a wider range of proteins.展开更多
基金Supported by the Science and Technology Special Fund of Ministry of Health, No. Wkz-2000-1-15
文摘AIM: To establish a model of drug-resistant neoplasms using a nude mice model, orthotopic transplantation of liver neoplasm and sporadic abdominal chemotherapy. METHODS: Hepatocellular carcinoma cells HepG2 were cultured and injected subdermally to form the tumor-supplying mice. The orthotopic drug-resistant tumors were formed by implanting the tumor bits under the envelope of the mice liver and induced by abdominal chemotherapy with Pharmorubicin. Physical examination, ultrasonography, spiral CT and visual inspection were used to examine tumor progression. RT-PCR and immunohistochemistry were used to detect expression of mdr1 mRNA and its encoded protein p-glycoprotein (p-gp). Tc-99m sestamibi scintigraphy was performed by obtaining planar abdominal images at 20 min after injection, and the liver/heart ratios were calculated. RESULTS: Post-implantation mortality was 0% (0/25), tumor implantation success was 90% (22/25), and the rate of implanting successfully for the second time was 100% (3/3). Tumor induction using Pharmorubicin was 80% (16/20). The mdrl mRNA expression of the induced group was 23 times higher than that of the control group, and p-gp protein expression was 13-fold higher compared to the control group. The liver/heart ratio (as assessed in vivo, using Tc-99m radiography) was decreased significantly in the induced group as compared to the control group. CONCLUSION: We have established an in vivo model of mdrl in nude mice by orthotopic transplantation of liver neoplasm coupled to chemotherapy. We propose that identification of drug resistance as characterized by decreased 99mTc-ppm radiography due to enhanced clearance by p-gp may be useful in detecting in vivo drug resistance, as well as a useful tool in designing more effective therapies.
文摘A series of experiments based on electrophoretical and biochemical assays were conducted to partially characterize proteinases present in the hepatopancreas and intestine of black carp （Mylopharyngodon piceus）, and investigate enzymatic activity and protein digestibility in vitro. Casein digestion assays revealed the presence of acidic proteinases with optimum activity in the range of pH 2.0-2.5 and alkaline proteinases with significantly higher activities both in the range of pH 8.1-8.6 and near pH 9.5. The inhibition and substrate specificity assays showed that trypsin and chymotrypsin are the main active components of the alkaline proteinases. The SDS-substrate-PAGE showed that the crude extract of black carp intestine had eight types of alkaline proteinases with the molecular mass range of 27.5-78.5 kDa while the crude extract of black carp hepatopancreas had six types of alkaline proteinases with the molecular mass range of 27.5-78.5 kDa. These enzymes were characterized as trypsin （27.5 kDa, 30.1 kDa）, chymotrypsin （40.5 kDa, 42.5 kDa）, serine proteinases （32.1 kDa, 33.2 kDa） and non-serine proteinase （61.5 kDa, 78.5 kDa）.In vitro protein digestibility assays showed that black cardcan be able to utilize a wider range of proteins.
