Objective To investigate the genetic relationship of the Dengue virus strains isolated in Guangdong province in 2006 and 2007, and to find the sources of these virus. Methods Serum samples of the dengue fever patients from 5 cities of Guangdong province in 2006 and 4 cities in 2007 were collected. Three pairs of primers that specific for amplifying the 3 overlap fragments of E gene of Dengue virus type Ⅰ were designed. RNAs were extracted from C6/36 cells treated with patients' serum. E genes were amplified by RT-PCR, purified and then sequenced directly. To obtain the E gene complete sequences, the raw sequences were assembled and edited. Obtained E genes were compared with E genes of other Dengue virus type Ⅰ published in the GenBank, analyzed by MEGA version 4.1 software. Results In 2006, virus circulating in Guaogzhou2006(EF508203) was closest to Vietnam2006(EU482539) with 99.3% nucleotides homology, Chaozhou2006 (EF508206) and Shantou2006 (EF508207) strains were closest to Japan2004 (AB178040) and Singapore2006 (EU081280) with 99.5% nucleotides homology, while Yangjiang2006 (EF508205) and Yangjiang2001 (EF508200) were closest to each other and both with 99.5% nucleotides homology to Thailand2001 (AY732482). All 4 Dengue virus strains circulated in 2007 were closest to Singapore2005(EU081276) with 99.7% nueleotides homology. Conclusion The Dengue viruses prevalent in 2006 were from different sources while those in 2007 came from the same origin. The data also showed that there was an endemic area of Dengue virus in Guangdong province.

OBJECTIVETo determine whether B7-2 could improve hepatitis B virus (HBV)-specific immunity induced by inoculation of a plasmid encoding HBV preS2+S HBV DNA vaccine.

METHODSB7-2 expression plasmids were inoculated with the DNA vaccine in the gastrocemius muscles. Then the cytolytic T Lymphocyte activity (CTL), the delayed-type hypersensitivity (DTH) response and the titers of anti-HBs were analysed.

RESULTSThe DTH response and CTL activity were significantly enhanced when B7-2 expression plasmids were coinoculated with the DNA vaccine (P<0.01), but the titers of anti-HBs were unaffected (P>0.05).

CONCLUSIONSThe results suggest that B7-2 expression plasmid could improve HBV specific cell-mediated immunity induced by HBV DNA vaccine, and the gene-based coinoculation strategy using HBV viral antigen and B7-2 costimmulating could be a powerful means of combating HBV infection.

Adjuvants, Immunologic ; Animals ; Antigens, CD ; immunology ; B7-2 Antigen ; Hepatitis B Antibodies ; biosynthesis ; Hepatitis B Vaccines ; immunology ; Hypersensitivity, Delayed ; immunology ; Male ; Membrane Glycoproteins ; immunology ; Mice ; Mice, Inbred C57BL ; Plasmids ; T-Lymphocytes, Cytotoxic ; immunology ; Vaccines, DNA ; immunology

Objective To investigate the value of the application of the fresh first morning midstream urine in cytological study of bladder cancer patients. Methods The results of the fresh first and second morning midstream urine cytological studies for 52 bladder cancer patients were analyzed.Continual three urine samples and single urine sample were treated as study objects respectively. The positive rates in different tumor stages and grades were evaluated. Results The positive rate of overall 52 patients was 78. 8 % (41/52) in fresh first morning midstream urine and 80. 8% ( 42 / 52) in the fresh second morning midstream urine. While in 156 single urine samples, the positive percentages were 56.4%(88/156) and 60. 9% (95/156). The positive rates of the fresh first and second morning midstream urine were 69.7% (23/33) and 72.7% (24/33) respectively in grade 1- 2 patients, and 44.4 % (44/99) and 48. 5 % (48/99) in 99 single urine samples. The positive rates of 42 non-muscle invasive bladder cancer patients were 73. 8% (31/42) and 76.2% (32/42) in the fresh first and second morning midstream urine, while in 126 single urine samples, the positive rates were 54.8% (69/126)and 57.1% (72/126). There were no significant differences between positive rate of the fresh first and second morning midstream urine in diagnosis of bladder cancer, low grade bladder cancer and nonmuscle invasive bladder cancer. Conclusion The fresh first morning midstream urine can be used for urine cytological study in the diagnosis of bladder cancer, even in the diagnosis of low stage and low grade bladder cancer.

Proteolytic processing of viral polyproteins is indispensible for the lifecycle of coronaviruses. The main protease (M(pro)) of SARS-CoV is an attractive target for anti-SARS drug development as it is essential for the polyprotein processing. M(pro) is initially produced as part of viral polyproteins and it is matured by autocleavage. Here, we report that, with the addition of an N-terminal extension peptide, M(pro) can form a domain-swapped dimer. After complete removal of the extension peptide from the dimer, the mature M(pro) self-assembles into a novel super-active octamer (AO-M(pro)). The crystal structure of AO-M(pro) adopts a novel fold with four domain-swapped dimers packing into four active units with nearly identical conformation to that of the previously reported M(pro) active dimer, and 3D domain swapping serves as a mechanism to lock the active conformation due to entanglement of polypeptide chains. Compared with the previously well characterized form of M(pro), in equilibrium between inactive monomer and active dimer, the stable AO-M(pro) exhibits much higher proteolytic activity at low concentration. As all eight active sites are bound with inhibitors, the polyvalent nature of the interaction between AO-M(pro) and its polyprotein substrates with multiple cleavage sites, would make AO-M(pro) functionally much more superior than the M(pro) active dimer for polyprotein processing. Thus, during the initial period of SARS-CoV infection, this novel active form AOM(pro) should play a major role in cleaving polyproteins as the protein level is extremely low. The discovery of AOM(pro) provides new insights about the functional mechanism of M(pro) and its maturation process.
Coronavirus ; metabolism ; Cysteine Endopeptidases ; Endopeptidases ; metabolism ; Humans ; Peptides ; chemistry ; metabolism ; Polyproteins ; chemistry ; metabolism ; Protein Binding ; SARS Virus ; chemistry ; metabolism ; Viral Proteins