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Biomedical subjects

Lin Liu

Publications and source records attributed to Lin Liu.

At least 55 records · Page 3Linked to original sources
PubMed2006

Fate of centrosomes following somatic cell nuclear transfer (SCNT) in bovine oocytes.

Cloning mammalians by somatic cell nuclear transfer (SCNT) remains inefficient. A majority of clones produced by SCNT fail to develop properly and of those which do survive, some exhibit early aging, premature death, tumors, and other pathologies associated with aneuploidy. Alterations of centrosomes are linked to aberrant cell cycle progression, aneuploidy, and tumorigenesis in many cell types. It remains to be determined how centrosomes are remodeled in cloned bovine embryos. We show that abnormalities in either distribution and/or number of centrosomes were evident in approximately 50% of reconstructed embryos following SCNT. Moreover, centrosome abnormalities and failed 'pronuclear' migration which manifested during the first cell cycle coincided with errors in spindle morphogenesis, chromosome alignment, and cytokinesis. By contrast, nuclear mitotic apparatus protein (NuMA) exhibited normal expression patterns at metaphase spindle poles and in 'pronucleus' during interphase. The defects in centrosome remodeling and 'pronuclear' migration could lead to chromosome instability and developmental failures associated with embryo production by SCNT. Addressing these fundamental problems may enhance production of normal clones.

Animals↗
PubMed2006

[Study of the quasispecies dynamics of serum hepatitis B virus in a patient with acute exacerbations of chronic hepatitis B].

OBJECTIVES: To investigate the quasispecies dynamics of hepatitis B virus (HBV) during the course of exacerbation and resolution of chronic hepatitis B in a patients. METHODS: Five serum samples were collected from a patient with two episodes of exacerbation and resolution of chronic hepatitis B. A method of PCR-TA cloning-conformation sensitive gel electrophoresis (CSGE)-sequencing was performed to study the dynamic changes of HBV quasispecies in basal core promoter (BCP), precore and core regions of HBV genome. RESULTS: Quasispecies complexity was 10 and 12 at the points of exacerbations, and 14 and 17 at the points of resolutions (t = 3.133, P < 0.05). Ratio of dominant quasispecies in HBV population was high (42.4% and 51.5%) during exacerbations and low (30.3% and 21.2%) during resolutions (t = 3.295, P < 0.05). All dominant quasispecies, except the one during the second resolution, carried core P5T, L60V, S155T, and precore G1896A mutations. CONCLUSION: The composition of HBV quasispecies changes due to the change of host immune status, and immune pressure might lead to the selection of immune escape mutants.

Adolescent↗
PubMed2006

[Analysis of the secreted proteins encoded by genes in genome of filamental fungus (Neurospora crassa)].

The completed genome sequence of filamental fungus Neurospora crassa has completed and 10,082 open reading frames (ORFs) were predicted in whole genome. Among them, 437 proteins were secreted ones based on the combination of prediction algorithms SignalP v3.0 and PSORT, transmembrane domains prediction algorithms TMHMM v2.0 and THUMBUP, potential GPI-anchor sites prediction algorithm big-PI predictor and the subcellular protein location prediction algorithm TargetP v1.01. The minimum ORF length of the encoding sequences for 437 secreted proteins was 252 bp, the maximum ORF length was 6 604 bp and average was 1 433 bp. The length of signal peptide of secreted proteins ranged from 15 to 59 amino acids. Among the 437 secreted proteins, 205 were provided with function description. The function of secretory proteins were involved in kinds of enzyme, cell energy, transmission, cell recovered itself and defense mechanism et al. These results implied that processes catalyzed by these proteins probably occurred outside of cells, at least partially.

Amino Acid Sequence↗
PubMed2006

[Enhancive effect of PLK1 gene silencing on sensitivity of K562/A02 cells to adriamycin].

BACKGROUND & OBJECTIVE: Polo-like kinase 1 (PLK1), an important cell cycle regulator, is highly expressed in many types of cancer, and is associated with oncogenesis, treatment effectiveness and prognosis. This study was to investigate the enhancive effect of small interference RNA (siRNA) targeting PLK1 gene on the sensitivity of K562/A02 cells to adriamycin (ADM). METHODS: siRNA plasmid vector specifically targeting PLK1 gene with enhanced green fluorescent protein (EGFP) was constructed and transfected into K562/A02 cells. The expression of PLK1 was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. The 50% inhibitory concentration (IC50) of ADM on K562/A02 cells was measured by MTT assay. Intracellular ADM accumulation and ADM-induced apoptosis of K562/A02 cells were detected by flow cytometry. RESULTS: After treatment with PLK1 siRNA, the mRNA and protein levels of PLK1 in K562/A02 cells were decreased by (61.9+/-2.5)% and (65.3+/-2.4)% of control. The relative reverse rate of sensitivity of K562/A02 cells to ADM was 67.8%. The intracellular accumulation of ADM was greatly increased, and ADM-induced apoptosis of K562/A02 cells was elevated from 11.33% to 54.39%. CONCLUSION: PLK1 gene silencing could enhance intracellular ADM accumulation in K562/A02 cells, improve sensitivity of K562/A02 cells to ADM, and induce cell apoptosis, therefore, reverse cell resistant to ADM.

Antibiotics, Antineoplastic↗
PubMed2006

[Progress of medical and combined treatment for esophageal carcinoma].

The combined treatment for esophageal carcinoma evoked increasing attention in clinic. The combination of radiotherapy, chemotherapy and operation is the tendency of combined treatment for esophageal carcinoma. The rational and efficient combined treatment has made more satisfied curative effect than single treatment, which improved the patients' long-term survival rate. Using new chemotherapeutic agents, exploring neoadjuvant chemotherapy, and renewing knowledge of adjuvant chemotherapy are important developments on medical treatment for esophageal carcinoma. This review discussed the progress of medical and combined treatment for esophageal carcinoma from the aspects of curative effect, survival rate, adverse events, and so on.

Antineoplastic Agents, Phytogenic↗
PubMed2006

[Effect of PLK1 gene silence on cell cycle, proliferation and drug resistance in K562/A02 cells].

The study was purposed to investigate the effect of small interference RNA (siRNA) targeting Polo-like kinase 1 (PLK1) gene on cell cycle progression, proliferation and drug resistance in K562/A02 cells. siRNA plasmid vector specifically targeting PLK1 gene with enhanced green fluorescence protein (EGFP) was transfected into K562/A02 cells. Expressions of PLK1 mRNA and protein were assayed by RT-PCR and Western-blot; cell proliferation was evaluated by direct cell counting after trypan blue staining. Cell cycle and intracellular adriamycin (ADM) accumulation was determined by flow cytometry; 50% inhibition concentration (IC50) of ADM on K562/A02 cells was determined by MTT method. The results showed that, as compared with control cells, siRNA plasmid reduced PLK1 mRNA expression by (34.7 +/- 2.1)% for 24 hours and by (56.6 +/- 1.5)% for 48 hours, PLK1 protein significantly decreased simultaneously by (49.9 +/- 3.2)% and by (62.1 +/- 1.7)%. After being transfected for 24 and 48 hours, the rate of survival cells decreased by 30% and 59% respectively. Forty-eight hours after transfection, the ratio of K562/A02 cells at G2/M increased by 2.77-fold, at the same time, intracellular ADM accumulation increased and the relative efficiency of K562/A02 cells to ADM was 73.8%. It is concluded that PLK1 gene silence can inhibit K562/A02 cell proliferation, induce cell cycle arrest at G2/M, and increase intracellular ADM accumulation, so that enhance cell sensitivity to ADM.

Cell Cycle↗
PubMed2006

[Effect of the NHE-1-specific inhibitor DMA on pHi, proliferation and apoptosis of HL-60/ADM cells in vitro].

The aim of this study was to evaluate the effect of dimethyl amiloride (DMA), a specific inhibitor of Na(+)/H(+) exchanger-1 (NHE-1), on intracellular pH value (pHi), proliferation and apoptosis of HL-60/ADM cells in vitro. After treatment with DMA at different doses, pHi of HL-60 and HL-60/ADM cell lines were determined by using pH-sensitive fluorescence dye BECEF-AM; the rate of growth inhibition of cells was detected with MTT assay; cell cycle was detected by flow cytometric DNA analysis; cell apoptosis was observed with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The results showed that pHi in HL-60/ADM cells was higher than that in HL-60 cells. After treatment with DMA at different doses, pHi decreased, the rate of growth inhibition and the rate of apoptotic cells in HL-60/ADM cells were all higher than those in HL-60 cells. Meanwhile, after treatment with DMA during 100 micromol/L to 150 micromol/L, the increase amplitude of G(0)/G(1) phase cells and the decrease amplitude of S + G(2)/M cells in HL-60/ADM cells were higher than those in HL-60 cells. It is concluded that by causing intracellular acidification, the NHE-1-specific inhibitor DMA inhibits proliferation of HL-60/ADM cells and induces apoptosis of HL-60/ADM cells, and the degree of this growth inhibition of HL-60/ADM cells is higher than that of HL-60 cells.

Amiloride↗
PubMed2006

[Aquaporin and Na+ transport of alveolar type II cells in rats with oleic acid-induced acute respiratory distress syndrome].

OBJECTIVE: To evaluate the capacity of active water and sodium transport of alveolar type II (AT II cells in rats with acute respiratory distress syndrome (ARDS). METHODS: AT II cells were isolated and purified from rats with ARDS, and the distribution of aquaporin-1 (AQP-1) on the cells was observed by immunocytochemistry, immunoelectron microscopy and Western blotting. The sodium currents were detected by patch-clamp technique in whole-cell recording mode. RESULTS: Immunocytochemistry showed staining for AQP-1 in rat AT II cells, and immunoelectron microscope demonstrated the presence of AQP-1, which was decreased as shown by Western blotting in comparison with the control group. The whole-cell currents were also decreased, but remained sensitive to terbutalin treatment. CONCLUSIONS: The capacity of active water and sodium transport is damaged, but not totally lost in AT II cells of ARDS rats. Terbutalin can increase the currents even if in pathological conditions. AQP-1 and sodium transport of AT II cells play an important role in pulmonary liquid clearance.

Acute Disease↗
PubMed2006

[In vitro effect of all-trans retinoic acid on cell adhesion molecule expression and adhesion capacity of bone marrow stromal cells in patients received peripheral blood stem cell transplantation].

The aim of this study was to evaluate the effect of all-trans retinoic acid (ATRA) on cell adhesion molecule expression and adhesion capacity of bone marrow stromal cells (BMSC) in patients after conditioning treatment for peripheral blood stem cell transplantation (PBSCT). BMSC of 27 patients before and after conditioning treatment for PBSCT were cultured in vitro. After treated with ATRA at 0.01, 0.1, or 1 micromol/L, expression of intercellular adhesion molecule-1 (ICAM-1) protein and vascular adhesion molecule-1 (VCAM-1) protein were detected by flow cytometry, and soluble ICAM-1 (sICAM-1) protein was determined by using radioimmunoassay. Then BMSC was co-cultured with CD34+ cells, and adhesion rate of BMSC to CD34+ cells was measured. The results showed that after pretreatment with conditioning regimen for PBSCT, the expressions of ICAM-1 and VCAM-1 proteins in BMSC and the expression level of sICAM-1 protein in supernatant of BMSC culture were down-regulated, and the adhesion rate of BMSC to CD34+ cells was decreased, after administration of ATRA, the expression of ICAM-1 protein in BMSC, sICAM-1 protein in culture medium and adhesion rate of BMSC to CD34+ cells all increased significantly, but expression of VCAM-1 protein changed no significantly. It is concluded that the ATRA can partly restore adhesion function of BMSC injured by pretreatment for PBSCT and contribute to hematopoietic reconstitution.

Adolescent↗
PubMed2006

[Simultaneous determination of four compounds in Sanjing Shuanghuanglian Oral Liquid by high performance liquid chromatography-diode array detection-electrochemical detection].

Chlorogenic acid, caffeic acid, baicalin and luteolin in Sanjing Shuanghuanglian Oral Liquid were simultaneously detected and identified using a high performance liquid chromatography coupled with diode array detection and electrochemical detection (HPLC-DAD-ECD). The separation was performed on a Zorbax SB-C18 column (150 mm x 4.6 mm i. d., 5.0 microm). The mobile phase consisted of (A) methanol and (B) methanol-water-acetic acid (50: 50: 1, v/v/v) using a linear gradient elution of 2%A-3%A at 0-3 min, 3%A-25%A at 3-15 min, 25%A-80%A at 15-20 min. The flow rate was 0.8 mL/min. The DAD detection was used at 275 nm. The ECD detection was done at 0.7 V. The column thermostat set at 30 degrees C. The limits of detection of the 4 compounds were 1 mg/L for chlorogenic acid, 0.2 mg/L for caffeic acid, 9 mg/L for baicalin, 7 mg/L for luteolin. The average recoveries were between 96.6%-99.6% with relative standard deviations (RSDs) of 2.5%-4.1%. The method is simple, rapid, reproducible and accurate. It can be used for the routine analysis of the four compounds in Shuanghuanglian Oral Liquid.

Caffeic Acids↗
PubMed2006

[Effects of soil moisture on the compensation effect of winter wheat with its partial roots cut off at returning green stage].

The study with pot experiment showed that after cutting partial roots at returning green stage, the growth of winter wheat was restrained at early growth stage, and the leaf area was decreased significantly from returning green to jointing stage but restored to the level of the control at flowering stage. Under high soil moisture condition, root cutting increased the values of chlorophyll fluorescence parameters ETR, phiPS II , qp and qn, at jointing stage significantly. The accumulated dry matter weight per stem after anthesis was significantly higher in root-cut wheat (0. 81 g) than in the control (0. 56 g) , with the accumulation coefficient (AC) of root-cut wheat increased by 38. 79% , but no significant difference was observed in root weight. Under low soil moisture condition, there were no significant differences in the values of chlorophyll fluorescence parameters and accumulated dry matter weight per stem after anthesis between root-cut wheat and the control, but the root weight of root-cut wheat decreased significantly. Soil moisture didn' t enhance the compensation effect of the aboveground biomass and grain yield of root-cut wheat. Root cutting reduced the water consumption of winter wheat significantly. Under high soil moisture condition, root-cut wheat saved 2 000 ml of water, and its water use efficiency (WUE) ( 1. 97 g x kg (-1)) was significantly higher than that of the control (1.70 g x kg(-1)). Under low soil moisture condition, root-cut wheat saved 1500 ml of water, but there was no significant difference in the WUE between root-cut wheat and the control.

Adaptation, Physiological↗
PubMed2005

Non-anthracycline based remission induction therapy for newly diagnosed patients with acute myeloid leukemia aged 60 or older.

We assessed remission rates and toxicity in 24 consecutive elderly (age>or=60) patients with untreated Acute myeloid leukemia (AML) who received the anthracycline-free combination of fludarabine, cytosine arabinoside and G-CSF (FLAG) as initial induction chemotherapy at our center. CR was achieved following one cycle of FLAG in 14 patients (58%). Another four patients cleared blasts from their bone marrow by day 30 without complete platelet recovery. Three patients died from infections prior to neutrophil recovery (12%). No other grade 3/4 toxicities and no clinically significant mucositis were seen. No significant association was found between age, WBC and cytogenetic risk group with likelihood of achieving CR. Fifteen patients proceeded to consolidation therapy and seven patients received a stem cell transplant (six autologous, one allogeneic). Primary induction with FLAG in elderly AML patients achieves a high remission rate without prohibitive mucosal or cardiac toxicity and may thus be considered as an alternative to standard anthracycline-based regimens in this setting.

Acute Disease↗
PubMed2005

Gadd45 beta and Gadd45 gamma are critical for regulating autoimmunity.

The number of effector T cells is controlled by proliferation and programmed cell death. Loss of these controls on self-destructive effector T cells may precipitate autoimmunity. Here, we show that two members of the growth arrest and DNA damage-inducible (Gadd45) family, beta and gamma, are critical in the development of pathogenic effector T cells. CD4(+) T cells lacking Gadd45beta can rapidly expand and invade the central nervous system in response to myelin immunization, provoking an exacerbated and prolonged autoimmune encephalomyelitis in mice. Importantly, mice with compound deficiency in Gadd45beta and Gadd45gamma spontaneously developed signs of autoimmune lymphoproliferative syndrome and systemic lupus erythematosus. Our findings therefore identify the Gadd45beta/Gadd45gamma-mediated control of effector autoimmune lymphocytes as an attractive novel target for autoimmune disease therapy.

Age Factors↗
PubMed2005

NIHSS training and certification using a new digital video disk is reliable.

BACKGROUND AND PURPOSE: NIH Stroke Scale certification is required for participation in modern stroke clinical trials and as part of good clinical care in stroke centers. The existing training and certification videotapes, however, are more than 10 years old and do not contain an adequate balance of patient findings. METHODS: After producing a new NIHSS training and demonstration DVD, we selected 18 patients representing all possible scores on 15 scale items for a new certification DVD. Patients were divided into 3 certification groups of 6 patients each, balanced for lesion side, distribution of scale item findings, and total score. We sought to measure interrater reliability of the certification DVD using methodology previously published for the original videotapes. Raters were recruited from 3 experienced stroke centers. Each rater watched the new training DVD and then evaluated one of the 3 certification groups. RESULTS: Responses were received from 112 raters: 26.2% of all responses came from stroke nurses, 34.1% from emergency departments/other physicians, and 39.6% from neurologists. One half (50%) of raters were previously NIHSS-certified. Item responses were tabulated, scoring performed as previously published, and agreement measured with unweighted kappa coefficients for individual items and an intraclass correlation coefficient for the overall score. kappa ranged from 0.21+/-0.05 (ataxia) to 0.92+/-0.09 (LOC-C questions). Of 15 items, 2 showed poor, 11 moderate, and 2 excellent agreement based on kappa scores. The intraclass correlation coefficient for total score was 0.94 (95% confidence interval, 0.84 to 1.00). Reliability scores were similar among specialists and centers, and there were no differences between nurses and physicians. kappa scores trended higher among raters previously certified. CONCLUSIONS: These certification DVDs are reliable for NIHSS certification, and scoring sheets have been posted on a web site for real-time, online certification.

Cerebrovascular Disorders↗
PubMed2005

Hemoglobin is expressed in alveolar epithelial type II cells.

Hemoglobin is the main oxygen carrying heme protein in erythrocytes. In an effort to study the differential gene expression of alveolar epithelial type I and type II cells using DNA microarray technique, we found that the mRNAs of hemoglobin alpha- and beta-chains were expressed in type II cells, but not in type I cells. The microarray data were confirmed by RT-PCR. The mRNA expression of both chains decreased when type II cells trans-differentiated into type I-like cells. Immunocyto/histochemistry revealed that hemoglobin protein was specifically localized in type II cells of a lung cell mixture and rat lung tissue. The endogenous synthesis of hemoglobin in alveolar epithelial cells suggests that hemoglobin may have unidentified functions other than oxygen transport in the lung.

Animals↗
PubMed2005

Characterization of protein kinase C theta activation loop autophosphorylation and the kinase domain catalytic mechanism.

Protein kinase C theta (PKCtheta), a member of the Ca(2+)-independent novel subfamily of PKCs, is required for T-cell receptor (TCR) signaling and IL2 production. PKCtheta-deficient mice have impaired Th2 responses in a murine ova-induced asthma model, while Th1 responses are normal. As an essential component of the TCR signaling complex, PKCtheta is a unique T-cell therapeutic target in the specific treatment of T-cell-mediated diseases. We report here the PKCtheta autophosphorylation characteristics and elucidation of the catalytic mechanism of the PKCtheta kinase domain using steady-state kinetics. Key phosphorylated residues of the active PKCtheta kinase domain expressed in Escherichia coli were characterized, and mutational analysis of the kinase domain was performed to establish the autophosphorylation and kinase activity relationships. Initial velocity, product inhibition, and dead-end inhibition studies provided assignments of the kinetic mechanism of PCKtheta(362)(-)(706) as ordered, wherein ATP binds kinase first and ADP is released last. Effects of solvent viscosity and ATPgammaS on PKCtheta catalysis demonstrated product release is partially rate limiting. Our studies provide important mechanistic insights into kinase activity and phosphorylation-mediated regulation of the novel PKC isoform, PKCtheta. These results should aid the design and discovery of PKCtheta antagonists as therapeutics for modulating T-cell-mediated immune and respiratory diseases.

Adenosine Diphosphate↗