[Synthesis and spectral characteristic of Ga-Fe3O4 at room temperature].

Gallium bearing ferrites with different gallium content were synthesized by oxidation of ferrous and gallium ions under alkaline condition and room temperature. The samples were subjected to IR, XRD, Mossbauer spectral analysis and magnetization characterization. The results indicated that the green-rust intermediate phase would be produced during the procedure of Ga-Fe3O4 formation, and the green-rust intermediate phase was converted to ferrites with spinel structure during the drying under hot-N2 atmosphere. With the introduction of gallium into the spinel structure, the interplanar crystal spacing of the spinel structure decreased, as indicated from XRD spectra, and the lattice vibration of M(T)-O-M(o) moved to the high-frequency resulting from IR spectra. A small amount gallium introduction entered the tetrahedral sites preferentially rather than the octahedral sites, and increasing gallium introduction would enhance the occupation of octahedral sites. Furthermore, a small content of gallium in the initial solution could prevent the formation of non-magnetic Fe2O3.

[Preparation and evaluation of sustained-release microsphere of Sanguis Draconis in vitro].

OBJECTIVE: To prepare sustained-release microsphere containing extract of Sanguis Draconis and to measure its dissolution in vitro. METHOD: Sustained-release microsphere was prepared with polylactic acid (PLA) as carriers using the oil-in-water (O/W) emulsion solvent evaporation method. The powder particle's characteristics of sustainded-release microsphere were evaluated comprehensively, and its dissolution characteristics in vitro were studied. RESULT: The microsphere was round and its surface was smooth, drug-loading rate was 21.97% and the entrapment rate was 55.76%, the accumulative release percentage was 76. 71% in 16 hours. CONCLUSION: The sustained release effect of Sanguis Draconis microspheres was formed with potentially wide applications.

[Establishment of stable expression cell lines for HBsAg variants and analysis of antigenicity].

OBJECTIVE: To study the mechanism of hepatitis B virus infected patients who is negative for HbsAg. METHODS: DNA sequences of 46 patients were analyzed. In these patients, HBsAg was negative but HBV DNA was positive and six new HBsAg variants were identified. Four of the six variants were combined point mutants and two were insertion variants. These S genes were subcloned into eukaryotic expression vector EBO-plpp, and the recombinant eukaryotic expression plasmids were transfected into COS7 cells. Cell lines expressing mutant type HBsAg were obtained. The supernatants were detected by ELISA and RIA. RESULTS: Only the two-amino acid-insertion variants could be detected and the others failed to react with polyclonal and monoclonal antibodies against HbsAg. CONCLUSION: The results indicated that the point mutations and insertions may result in a conformational change of the S gene, which affect HBsAg antigenicity, suggesting a possible relationship between the variants and the negative conversion of HBsAg of the patients.

[Construction and biological activity assessment of core mutants of hepatitis B virus adr subtype].

OBJECTIVE: To construct the core mutant (L97 and V60) plasmids of hepatitis B virus (HBV) and assess their biological activity. METHODS: Site-directed mutagenesis was performed to induce specific core point mutations in HBV adr suhtype 1.2 copy genome plasmid p3.8 II. The plasmids were transfected into HepG2 cells via liposome, and intracellular HBV DNA was analyzed by Southern hybridization, while extracellular HBV antigens (HBsAg and HBeAg) in the culture supernatant were assayed by enzyme-linked immunosorbent assay. RESULTS: Sequence analysis of the constructed mutant plasmids p3.8 L97 and p3.8 V60 demonstrated mutations at 2 189 A C and 2 086 C HBV adr subtype genome core mutant (L97 and V60) plasmids we have constructed possess biological activity.G respectively. These mutant plasmids exhibited HBV DNA replication activity and gene expression in host cells. CONCLUSION: HBV adr subtype genome core mutant (L97 and V60) plasmids we have constructed possess biological activity.

Construction of recombinant eukaryotic expression plasmid containing hepatitis B virus genome with partial deletion of the core promoter.

OBJECTIVE: To construct an eukaryotic expression vector containing the full-length genome with partially deleted core promoter of hepatitis B virus (HBV). METHODS: A linearized genome containing the entire HBV 3.5 kb mRNA transcriptional units (P3.8 I plasmid) was used, which initiated from the upstream sequences of the basic core promoter. The objective eukaryotic expression vector was constructed by molecular cloning and PCR-based site-directed mutagensis in vitro, and identifcation was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by cloning and sequencing analysis. RESULTS: The eukaryotic expression vectors containing HBV genomes with 20/21 bp deletion (position 1 748/1 747 to 1 767) in the core promoter or with precore stop mutation at nucleotide 1896 as well were constructed successfully as confirmed by sequence analysis with RFLP. CONCLUSION: The recombinant expression vector may lay the foundation for further studies into the biological significance of the above mentioned mutations in vitro.

Determination and analysis of complete nucleotide sequence of Chinese genotype D hepatitis B virus: the first report.

OBJECTIVE: To determine the complete nucleotide sequence of a Chinese hepatitis B virus (HBV) strain of genotype D. METHOD: The complete nucleotide sequence of HBV derived from a Chinese chronic asymptomatic carrier was amplified by PCR and cloned to conduct sequence analysis. Homology of the resulted nucleotide sequence with those of published HBV strains was assessed by using DNASIS, and complete sequence analysis of the phylogenetic tree of 30 genotype D HBV strains conducted by the assistance of Clustalw. RESULTS: With the complete nucleotide sequnce of 3 182 bp, this HBV strain belongs to ayw3 subtype and D genotype, with the Genebank accession number AF280817. Its complete nucleotide homology is 98.3% to 94.5% with the published sequences of genotype D HBV strains and less than 89.5% with the other HBV strains of genotype A, B, C, E, F and G published in GenBank. CONCLUSION: The evolutionary relations of the complete nucleotide sequence of this HBV strain is the closest to those of the 4 Swedish strains out of the 30 genotype D strains published in GenBank.

Hot-spot mutations in HBV pre-C region in HBeAg-negative patients with severe hepatitis B.

OBJECTIVE: To investigate the association of hot-spot mutations in hepatitis B virus (HBV) pre-C region with the occurrence and outcome of severe hepatitis B. METHODS: A total of 68 patients with severe hepatitis B negative for hepatits B e antigen (HBeAg) were enrolled in this study, including 6 cases of acute, 38 cases of subacute and 24 chronic severe hepatitis B, with another 44 HBeAg-positive patients with chronic hepatitis B serving as control. Mismatch PCR and restriction fragment length polymorphism analysis were employed to examine the mutations of T1862 and A1896 in this 2 groups of patients. RESULTS: The mutation rates at A1896 and T1862 were 66.7% (4/6) and 0 (0/6) respectively in acute severe hepatitis B cases, 42.1% (16/38) and 15.8% (6/38) in subacute severe hepatitis, 25.0% (6/24) and 16.7% (4/24) in chronic severe hepatitis, and 45.5% (20/24) and 2.3% (1/44) in chronic hepatitis cases. There were significant differences in terms of T1862 mutation between patients with severe hepatitis and chronic hepatitis (P<0.01). CONCLUSION: T1862 mutation is closely related to the exacerbation of chronic hepatitis, while the role of A1896 mutation in this process requires further investigation.

Detection of interleukin-6 and -12 in of hepatitis B patients and its clinical significance.

OBJECTIVE: To investigate the clinical significance of detecting interleukin-6 (IL-6) and interleukin-12 (IL-12) in the immunological mechanism of hepatitis B virus infection (HBV). METHODS: Serum IL-6 and IL-12 levels were determined using enzyme-linked immunosorbent assay in patients with chronic, acute or advanced hepatitis B as well as in healthy subjects. RESULTS: In chronic, acute, severe hepatitis B patients, serum IL-6 levels were significantly elevated as hepatitis worsened (199.7+/-26.9, 129.5+/-22.8, 286.1+/-56.7 pg/ml respectively), in that order compared with the normal control levels (56.41+/-12.9 pg/ml). IL-12 levels, in contrast, tended to be lowered with the deterioration of hepatitis (24.6+/-13.4, 135.3+/-60.8, 19.7+/-9.0 pg/ml respectively), in that order, with the control level of 34.7+/-11.8 pg/ml. CONCLUSION: Serum IL-6 level is closely correlated to the degree of hepatocyte damage in hepatitis B, while IL-12 may be instrumental in the defense mechanism against HBV infection, and IL-12 level elevation can be indicative of hepatitis recovery.