Biomedical subjects

Yan-Li Zhang

Publications and source records attributed to Yan-Li Zhang.

7 recordsLinked to original sources

PubMed2006

Human Flt3 ligand from Pichia pastoris inhibits growth of lymphoma and colon adenocarcinoma in mice.

UNLABELLED: Potent effects of Flt3 ligand (FL) on the development of the immune system have generated much interest in application of FL in cancer immunotherapy. OBJECTIVE: To evaluate the effects of Pichia pastoris secreted rhFL on the growth of mouse EL-4 lymphoma and C26 colon adenocarcinoma injected in syngeneic mice for the first time. METHODS: Mice were placed into one of two treatment groups. 2 x 10(5) EL-4 or C26 cells were injected subcutaneously (SC.) into mice on day 0. Group 1 received subcutaneous PBS injections from Day -7 to Day 14 and group 2 received subcutaneous rhFL injections at 30 microg/day from Day -7 to Day 14. Serial tumor areas were measured. On Day 22, mice from each group were sacrificed, and weight of tumors and spleens were evaluated. Data analysis used Student t tests. RESULTS: Pichia pastoris secreted rhFL resulted in tumor growth delay for both EL-4 lymphoma and C26 colon adenocarcinoma compared with control (P < 0.01). Tumors from rhFL-treated mice were smaller (P < 0.01) than controls while spleens larger (P < 0.01) than controls. Histological examination of tumor sections revealed an obvious increase in regions composed largely of infiltrating cells in the rhFL-treated tumors. Infiltrating cells could be detected in clusters among tumors from mice treated with rhFL whereas these cells were only occasionally detected in sections of control tumors. CONCLUSION: Treatment of rhFL expressed from Pichia pastoris resulted in an antitumor response against EL-4 and C26 tumors injected in syngeneic mice.

Adenocarcinoma↗

PubMed2005

High-level expression of human stem cell factor fused with erythropoietin mimetic peptide in Escherichia coli.

Stem cell factor (SCF) and erythropoietin are essential for normal erythropoiesis and induce proliferation and differentiation synergistically for erythroid progenitor cells. Here, we report our work on construction of SCF/erythropoietin mimetic peptide (EMP) fusion protein gene, in which human SCF cDNA (1-165aa) and EMP sequence (20aa) were connected using a short (GGGGS) or long (GGGGSGGGGGS) linker sequence. The SCF/EMP gene was cloned into the pBV220 vector and expressed in the Escherichia coli DH5alpha strain. The expression level of the fusion protein was about 30% of total cell protein. The resulting inclusion bodies were solubilized with 8 M urea, followed by dilution refolding. The renatured protein was subsequently purified by Q-Sepharose FF column. The final product was >95% pure by SDS-PAGE and the yield of fusion protein was about 40 mg/L of culture. UT-7 cell proliferation and human cord blood cell colony-forming assays showed that the fusion proteins exhibited more potent activity than recombinant human SCF, suggesting a new strategy to enhance biological activities of growth factors.

Cell Line, Tumor↗

PubMed2005

Visceral response to acute retrograde gastric electrical stimulation in healthy human.

AIM: To investigate the visceral response to acute retrograde gastric electrical stimulation (RGES) in healthy humans and to derive optimal parameters for treatment of patients with obesity. METHODS: RGES with a series of effective parameters were performed via a bipolar mucosal electrode implanted along the great curvature 5 cm above pylorus of stomach in 12 healthy human subjects. Symptoms associated with dyspepsia and other discomfort were observed and graded during RGES at different settings, including long pulse and pulse train. Gastric myoelectrical activity at baseline and during different settings of stimulation was recorded by a multi-channel electrogastrography. RESULTS: The gastric slow wave was entrained in all the subjects at the pacing parameter of 9 cpm in frequency, 500 ms in pulse width, and 5 mA in amplitude. The frequently appeared symptoms during stimulation were satiety, bloating, discomfort, pain, sting, and nausea. The total symptom score for each subject significantly increased as the amplitude or pulse width was adjusted to a higher scale in both long pulse and pulse train. There was a wide diversity of visceral responses to RGES among individuals. CONCLUSION: Acute RGES can result in a series of symptoms associated with dyspepsia, which is beneficial to the treatment of obesity. Optimal parameter should be determined according to the individual sensitivity to electrical stimulation.

Adult↗

PubMed2005

Functional expression, purification, and characterization of human Flt3 ligand in the Pichia pastoris system.

Flt3 ligand (FL) is a potent hematopoietic cytokine that affects the growth and differentiation of hematopoietic progenitor and stem cells both in vivo and in vitro. Pichia pastoris transformants secreting high-level rhFL were obtained using 'yeastern blotting' method and the expression level in liquid was about 30 mg/L. rhFL was purified to about 95% purity with overnight dialysis, filtration and an anion-exchange step. Further purification steps employing Sephacryl S-200 and reverse-phase HPLC raised the purity to over 99%. The purified rhFL possessed correct N-terminal amino acid sequence and positive Western blotting bands. SDS-PAGE and mass spectrometry analysis showed molecular weight of rhFL was about 21 and 34 kDa, suggesting that rhFL was glycosylated. The result of capillary electrophoresis showed that its pI is 3.12-4.72. Endo H deglycosylation analysis indicated that there was O-glycosylation besides N-glycosylation in rhFL secreted from P. pastoris. Bioactivity assay showed that the purified rhFL had dose-dependent expansion activity on bone marrow nucleated cells.

Animals↗

PubMed2005

A new cytotoxic lanostane triterpenoid from the basidiomycete Hebeloma versipelle.

A new cytotoxic lanostane triterpenoid, 24(E)-3beta-hydroxylanosta-8,24-dien-26-al-21-oic acid (1), was isolated from the fruiting bodies of the mushroom Hebeloma versipelle. The structure was elucidated on the basis of spectroscopic studies including 2D NMR experiments. Compound 1 moderately inhibited the growth of several tumor cell lines (IC50 10-25.0 microg/ml).

Antibiotics, Antineoplastic↗

PubMed2004

Diterpenoids from Isodon melissoides.

Nine new diterpenoids, melissoidesins M-U (1-9), along with five known analogues, melissoidesin F (10), xindongnin B (11), melissoidesin G (12), melissoidesin E (13), and dawoensin A (14), were isolated from the aerial parts of Isodon melissoides. The structures of new compounds were elucidated by analysis of spectral evidence including extensive 2D NMR data. Compounds 2, 3, 7, 11, 12, and 14 showed cytotoxicity against the human tumor BGC-823 cell line with IC(50) values less than 10 microg/mL, respectively.

Antineoplastic Agents, Phytogenic↗

PubMed2002

[Analysis of the clinical manifestations and imaging features of Budd-Chiari syndrome: report of 81 cases].

A comprehensive analysis of the clinical manifestations and imaging features in 81 cases of Budd-Chiari syndrome (BCS) was conducted, and criteria for classification of this disease was proposed. Diagnostic modalities included digital subtraction angiography, ultrasound, computed tomography and percutaneous transhepatic cholangiography. The main clinical manifestations of BCS was inferior vena cave obstruction and portal hypertension. Wall thickening of the gallbladder was indicative of BCS during imaging diagnosis.

Adolescent↗