Biomedical subjects

Juan Liu

Publications and source records attributed to Juan Liu.

41 records · Page 3Linked to original sources

PubMed2003

Dynamic alteration of HBV markers on active HBV replicative recipients after liver transplantation: a preliminary report.

OBJECTIVE: To investigate the dynamic alternations of HBV markers of active HBV replication recipients receiving lamivudine prophylaxis after liver transplantation. METHODS: Serial liver biopsy samples and sera were obtained from 15 recipients and examined with enzyme-linked radioimmunoassay for HBsAg, HBeAg, HBsAb, HBcAb and HBeAb, and fluorescent quantitative assay for quantitation of HBV DNA in serum. Immunohistochemical staining of HBsAg, HBcAg and HBV DNA hybridization in situ were used to detect HBV markers in liver biopsy samples. RESULTS: 100 mg lamivudine taken orally every day for 2 weeks before transplantation enabled 12 (80%) of 15 active viral replication recipients (HBV DNA positive) to converse to HBV DNA negative. HBsAb, HBcAb and HBeAb in serum emerged in 1-2 weeks after liver transplantation, and disappeared gradually within 6 months; HBV DNA fluorescent quantitative assay showed constant negativity in serum. Immunohistochemical staining of HBsAg, HBcAg and HBV DNA hybridization in situ in liver biopsy samples showed negative results synchorously. Eight of the 15 HBV active replication recipients lost HBV markers thoroughly both in serology and tissue staining as well as HBV DNA hybridization in situ of serial liver biopsy samples from 12 to 44 weeks after liver transplantation. Should any of HBsAg, HBeAg in serology and HBsAg, HBcAg in immunohistochemical staining was positive, or HBV DNA detectable in serum, or HBV DNA hybridization in situ in liver tissue positive, allograft HBV reinfection or De novo liver allograft infection could be diagnosed. Furthermore, if associated with elevation of ALT and bilirubin, the diagnosis of HBV hepatitis recurrence could be established. CONCLUSION: Allograft HBV reinfection or De novo liver allograft infection in active viral replication recipients could be prevented with lamivudine regimen, and further clearance of HBV may be possible if proper measures are taken.

Adult↗

PubMed2003

[Construction of a SV40 promoter specific artificial transcription factor].

Transcriptions are regulated by transcription factors. Natural transcription factors usually consist of at least two functional domains: a DNA-binding domain and an effector domain. According to this, novel artificial transcription factors are designed to up or down regulate transcription and expression of a target gene. The Cys2-His2 zinc finger domain is a DNA-binding module that has been widely used as the DNA-binding domain in artificial transcription factors. Each zinc finger domain, which comprises about 30 amino acids that adopt a compact structure by chelating a zinc ion, typically functions by binding 3 base pairs of DNA sequence. Several zinc fingers linked together would bind proportionally longer DNA sequences. According to the "bipartite complementary" library strategy, a pair of zinc finger phage display libraries were constructed. After construction of the libraries, a 9bp sequence (5'-GCAGAGGCC-3') on the promoter of SV40 was chosen as a target for next step. After parallel selection, PCR amplification, desired fragments recovery, re-ligation, and additional rounds of selection, phage enzyme-linked ELISA experiments were performed to identify specific binding clones displaying the zinc fingers with predetermined sequence-specificity to our target sequence. Then two clones with strong ELISA signals were chosen to be tested for binding both to its full target site (5'-GCAGAGGCC-3') and to sites containing single transition mutations. The binding specificity of one of the two clones (clone 3) was shown to be fairly good. The three-finger DNA-binding domain targeted to SV40 promoter, that is, zinc finger sequences on clone 3, was fused to KOX1 suppression domain KRAB and cloned into pcDNA3.1 (+) (which expression product was artificial transcription factor). The zinc fingers (which expression product was the DNA-binding domain of artificial transcription factor) and KRAB domain only (which expression product was effector domain of artificial transcription factor) were also cloned separately into the same expression vector. All constructs contained an N-terminal nuclear localization signal. Every of the vectors (including pcDNA3.1 (+) without inserting sequences) were cotransfected with pGL3-Control and pRL-TK and the activity of luciferase was used to indicate the function of product from transfected expression vectors. Our artificial transcription factor was proved to repress the expression of reporter gene efficiently,while with only DNA-binding domain or effector domain the repression was not remarkable. By adding different effector domains and changing the DNA-binding domain, artificial transcription factor would have a wide range of potential applications.

Enzyme-Linked Immunosorbent Assay↗

PubMed2003

[The breeding of high glutathione-producing strain and optimization of culture condition].

High glutathione-producing strain ZJF-71 was constructed by primary screening,isolation of haploid, mutagenesis and protoplasts fusion. The yield of glutathione of the fusant ZJF-71 is 1.59 and 1.42 times that of the parental strains Y64 and Y247, respectively. The factors that affected the biomass and glutathione content of the fusant ZJF-71 were also tested. The highest level of glutathione was obtained in 32 h at 30 degrees C and 200 r/min, when 30 mL of culture in 250- mL shake flasks was incubated in fermentation medium which contained (w/v): 6% cane sugar, 1% peptone, 1% yeast extract, and 2mmol/L cysteine. Glutathione yield under the optimal fermentation condition showed a 2.8-fold improvement over that of the initial condition. The fusant ZJF-71 is stable in genetic by analysis of genetic stability.

Biomass↗

PubMed2002

[Effect of serum leptin on nutritional status of patients with cancer].

In order to investigate the effect of serum leptin and its potential as a parameter for the accessment of nutritional status of patients with cancer, serum leptin concentration, body mass index (BMI), blood erythrocyte, hemoglobin, serum albumin, lipid and lipoprotein concentration of 325 cancer patients and 66 healthy controls are meatured. The incidence of patients with BMI < 18.5, hypoalbumia, anemia, hypercholesterolemia, and hypertriglyceridemia is 23%, 14%, 42%, 17.2%, and 21.4% respectively. The incidence of patients with BMI < 18.5 in pulmonary carcinoma is obviously lower than that of those with gastric carcinoma (P = 0.022). The incidence of patients with hyperglycosemia and hypertriglyceridemia in pulmonary carcinoma is obviously higher than that of those with gastric carcinoma (P = 0.003 and P = 0.029 respectively). Serum leptin concentration in the patients with malnutrition is significantly lower than that of those with no malnutrition and that of those obese patients (P = 0.000). There is no significant difference in serum leptin concentration between patients with cancer and healthy control persons with same gender and with BMI value ranged from 18.5 to 25. It is shown that the BMI, gender and serum albumin concentration are all influencing factors to the serum leptin concentration and the serum leptin concentration is significantly correlated with BMI, gender and serum albumin concentrations (r = 0.599-0.698, P = 0.000). The above mentioned results from this study indicate that there is a high anemia incidence of patients with cancer. Serum leptin concentration can reflect the changes in BMI and nutritional status of the patients with cancer. The serum leptin concentration has the potential of being a parameter for assessing nutritional status of the patients with cancer.

Adenocarcinoma↗

PubMed2002

[Study on morphology of the pollen of 4 species from Geranium in Heilongjiang Province].

Morphology of the pollen of 4 species from Geranium in Heilongjiang province which are G. wilfordii Maxim., G. sibiricum L., G. platyanthum Duthie. and G. dahuricum DC. were observed with optical microscope and scanning electron microscope. The results showed pollen grains of the four species were nearly spherical, with short clavate-shaped, net-shaped and cave-shaped veins on the outer walls and three short-furrow germ pores. Both the clava size and number of clava per unit surface area were different. This paper provided evidences for palynology classification of Geranium.

China↗