Studies On The Infectiocn Rate, Pathogenicity, Gene Varation Of TTV And Methods Of Isolating Novel Hepatitis Virus

In the clinical practice, it was found that there were up to 10% of hepatitis patients without any known markers of hepatitis virus, which was called as non-A to-G hepatitis virus. HGV only stood for small part of the unkown hepatitis virus. These foundings indicated that there exsisted novel hepatitis-causing agents other than hepatitis A to G. TTV was the product of such inference. It was found by representational difference analysis (RDA). In the study we established two methods to extract TTV DNA from serum and applied them in comparing the infection rate of some regions of China by nested PCR. We also analyzed the sequence varation of TTV from several Chinese cities and detected the TTV DNA from the parrafin-embeded liver tissues. Baed on the idea that TTV, possiblly like HGV, had weak pathogenicity, we used subtractive suppressive hybridization(SSH) and RDA, trying to find novel genes from the infected monkeys inocculated with serum of patients with non-A to-G hepatitis.1 Establishment and comparison of two methods of isolating TTV DNAWe applied the STG and glass milk methods to isolate TTV DNA from the serum of 97 patients with HCC. The primers were synthesized according to the Japanese TTV sequence. Ampication was done by Nested PCR. The positive rate of PCR was 16.5%(17/97) by glass milk method and 4.1%(4/97) by STG method. The difference was significant (p<0.05), which was caused by the different starting volume of serum. Glass milk method costed less, so it suited for the PCR detection of plentiful samples, while STG method was useful when serum was not easy to get because it only need...