Comparative,medicine is a branch of laboratory animal seiences which also cuts the first edge of the morden medical sciences.This article mainly discussed the origin of comparative medicine,its contributions to life sciences.relationships between it and laboratory animal science,its importance for life science and medical researches.Most of all.the necessarity and feasibity to teach comparative medicine for the undergraduate students were highlighted

Aim To screen the express-altered proteins before or after effect of Ecdysterone on HepG_2 cell model of insulin resistance by the strategy of comparative proteomics, which may approach new proves exploring the target of sensitizer.Methods HepG_2 cells were incubated with 5×10~(-7) mol·L~(-1) insulin for 16 h, and glucose consumption was determined. After treatment, the insulin resistant cells were incubated with 10~(-5) mol·L~(-1) Ecdysterone for 24 h.Then glucose consumption contents were determined. The proteins of two groups before and after treatment with Ecdysterone were extracted by lysis buffers. The express-altered proteins were screened by 2-DE technique.Some of them were analyzed by MALDI-TOF-MS mass spectrometry and MS-Fit database.Results 53 express-altered protein spots of insulin resistant HepG_2 cells before and after treated by Ecdysterone were screened by 2-DE technique,in which 35 ones were up-regulated and the others down-regulated, 6 spots of which were analyzed by MALDI-TOF-MS mass spectrometry and MS-Fit database.Conclusion The target of Ecdysterone as a sensitizer involves many proteins and kinases which correlate insulin resistant. These results lay a foundation for further studies on the function of these target proteins.

Objective To establish a simple, stable, specific and sensitive method for detection of Tyzzer ’ s or-ganism by reverse dot blotting ( RDB) .Methods Primers and specific probes were designed according to the conservative sequence of Tyzzer 16S rDNA.The forward primer was labeled with biotin .The reverse dot blotting method was established followed by PCR amplification .The specificity and sensitivity of this method were determined .Next, 41 mice and 38 rats were examined by RDB , ELISA and IFA .Results The RDB method showed a high specificity , and in the testing of the 79 laboratory animals , its limit of detection was 4.5 ng/μL.Compared the results of ELISA and IFA , its consistence with ELISA was 100%and the positive rate was 7.59%(6/79), the consistence with IFA was 92.4%(73/79), and the posi-tive rate was 0%.Conclusions An accurate, sensitive and specific method in combination with PCR and RDB in detection of Tyzzer’ s organism is established in this study .

Objective To construct rCB1 gene eukaryotic expression vector, detect its expression in the cell, and explore its influence on apoptosis in human cervical cancer CaSki cells.Methods The total RNA was extracted from rat brains.The rCB1gene was amplified by RT-PCR.The pcDNA3.1(+)-rCB1 was constructed by enzyme digestion, purifi-cation, bind the PCR purification products and pcDNA3.1 (+) DNA.The pcDNA3.1 (+)-rCB1 plasmid was transfect-ed into HEK293 and CaSki cells by liposomes.The expression and localization of rCB1 were detected by Western blot and immunofluorescence combined with confocal laser scanning microscopy.The apoptosis rate of CaSki cells was detected by flow cytometry.The expression of rCB1, Bcl-2, Bax and Bad was detected by Western blot and real-time fluorescence quantitative RT-PCR (qRT-PCR).Results The 5300 bp pcDNA3.1(+) and 1500 bp rCB1 were obtained after diges-ting the pcDNA3.1 ( +)-rCB1.The result of sequencing was in agreement with the sequence of rCB1 gene ( NM_012784.4 ) .The rCB1 expressed in the membrane and cytoplasm when pcDNA3.1 (+)-rCB1 plasmid was transfected into HEK293 cells.The apoptosis rate of rCB1 group was increased compared with the blank group when pcDNA3.1 (+)-rCB1 plasmid was transfected into CaSki cells (P<0.05).Compared with the blank group, rCB1 gene upregulated the expres-sion of Bax and Bad, and suppressed the expression of Bcl-2.The statistical difference was significant ( P <0.05). Conclusions The pCDNA3.1(+)-rCB1 eukaryotic expression vector is constructed successfully.It is found that rCB1 is expressed in membrane and cytoplasm of HEK293 cells.rCB1 can significantly promote the apoptosis in cervical cancer CaSki cells by up-regulating the expression of Bax and Bad, and down-regulating the expression of Bcl-2 as well.

OBJECTIVETo generate a mouse model of chronic hepatitis B (CHB) infection by performing in vivo transduction of hepatitis B virus (HBV) covalently closed circular (ccc)DNA.

METHODSNude mice were injected with HBV cccDNA at doses of 1.5, 1.0 or 0.5 mug/ml. A control group was generated by giving equal injection volumes of physiological saline. The serum levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) on post-injection days 1 and 3, weeks 1-6, 8 and 10 were assayed by reflection immunoassay. At post-injection week 10, all animals were sacrificed and liver tissues were collected. Copies of HBV DNA in serum and liver tissue were detected by real-time PCR. HBV antigens in liver tissue were detected of by immunohistochemistry. Pathological analysis of liver tissue carried out with hematoxylin-eosin staining. Linear correlation of data was determined by statistical analysis.

RESULTSHBsAg and HBeAg were detected in sera from all three groups of cccDNA-injected mice staring at post-injection day 1 and lasting through week 10. The levels of HBsAg over the 10-week period showed two patterns of increase-decrease;the lowest level was detected at week 4 and the highest level was detected at week 8. In contrast, the levels of HBeAg over the 10-week period showed three patterns of increase-decrease; the lower levels were detected at weeks 2 and 4 and the higher levels at weeks 3 and 6. HBV DNA copies in liver tissues showed a cccDNA dose-dependent descending trend over the 10-week study period (1.5 mug/ml:1.14E+07 ± 6.51E+06 copies/g, 1.0 mug/ml:9.81E+06 ± 9.32E+06 copies/g, and 0.5 mug/ml:3.72E+06 ± 2.35E+06 copies/g; Pearson's r =0.979). HBV DNA copies in sera showed the pattern of 1.0 mug/ml cccDNA more than 1.5 mug/ml cccDNA more than 0.5 mug/ml cccDNA, and in general were higher than those detected in the liver tissues. Liver tissues from all cccDNA-injected mice showed positive immunohistochemistry staining for both HBsAg and HBeAg. HE staining showed that the liver tissues of all cccDNA-injected mice had severe fatty and vacuolar degeneration and less obvious structure of liver lobules (compared to the liver tissues from control mice).

CONCLUSIONThe CHB mouse model successfully established in this study by in vivo transduction of HBV cccDNA may represent a useful tool to study the pathogenic mechanisms and potential antiviral treatments of human CHB.

Animals ; DNA, Circular ; administration & dosage ; DNA, Viral ; administration & dosage ; Disease Models, Animal ; Hepatitis B Surface Antigens ; blood ; Hepatitis B e Antigens ; blood ; Hepatitis B virus ; genetics ; physiology ; Hepatitis B, Chronic ; virology ; Male ; Mice ; Mice, Nude ; Transduction, Genetic ; Virus Replication