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Biomedical subjects

Jun Liu

Publications and source records attributed to Jun Liu.

At least 199 records · Page 11Linked to original sources
PubMed2005

[Postoperative mortality after gastrectomy for gastric cancer: analysis of 1142 cases].

OBJECTIVE: To analyze postoperative morbidity and mortality after gastrectomy for gastric carcinoma and identify main risk factors influencing mortality. METHODS: A total of 1142 patients with gastric cancer received gastrectomy between January 1989 and April 2004. The patients were divided into three groups according to different period, the first group (n=405): from January 1989 to January 1994; the second group (n=377): from February 1994 to January 1999; the third group (n=360): from February 1999 to March 2004. Postoperative morbidity and mortality were compared among three groups, the risk factors influencing postoperative mortality were determined by multiple logistic regression analysis. RESULTS: The total postoperative morbidity and mortality for all patients were 11.2% (128/1142) and 3.6% (41/1142), respectively. The postoperative morbidity was 13.1%, 10.1%, and 10.3% in the first, second, and third group respectively, there was no significant difference in morbidity among the three groups (P > 0.05). The postoperative mortality was 4.7%, 3.4%, and 2.5% respectively (P > 0.05), there was no significant difference in mortality among the three groups (P > 0.05). The most common postoperative complication was anastomotic leakage (24.2%, 31/128). The following clinicopathologic factors were found to be correlated with postoperative mortality: stage IV; palliative excision; multivisceral resection; and preoperative complications (P< 0.05). Multivariate analysis revealed that the extent of lymph node dissection or surgical procedure were not main risk factors influencing mortality. CONCLUSION: Patients with advanced gastric cancer have a high risk of postoperative mortality. Unnecessary lymph node dissection or multivisceral resection should be avoided for patients with stage IV gastric cancer.

Adult↗
PubMed2005

In vitro expression and antibody preparation of black carp (Mylopharyngodon piceus) GH.

The cDNA fragment encoding the mature polypeptide of growth hormone (GH) for the black carp (Mylopharyngodon piceus) was PCR amplified and subcloned into pET-28a. The recombinant expression plasmid pET-bcGH was transformed into E.coli BL21(DE3) and fusion polypeptide containing a 6xHis-tag at the N-terminus was expressed after IPTG induction. The fusion protein band of 23 kDa or so showed immunoreactivity to the polyclonal antibody aganist grass carp GH. The recombinant GH for black carp was purified by affinity chromatography and dialysis. Using the fusion protein as an antigen, through the modified immunization method, the polyclonal antiserum to black carp GH was obtained. Immunochemistry results showed that the antiserum could detect the antigen as low as 4 ng. The protein of 21 kDa in black carp pituitary protein extracts and blood serum could be detected by western blot analysis in which polyclonal antiserum to black carp GH was used as the primary antibody. All these results showed that the polyclonal antiserum against black carp GH was not only effective but also highly specific.

Animals↗
PubMed2005

[Study on breeding up high-yield strain of taxol by protoplast mutagensis].

In order to obtain resistant mutants to nystatin, ultraviolet radiation and LiCl were used to mutagenize the protoplasts of taxol-producing fungi NCEU-1, and four positive mutants with high yield of taxol were screened out on nystatin flat. After further screening experiments on fermentation, a mutant strain--UL04-5 which was able to produce taxol with high yield and could be stably passed on in genetics was eventually found, it's ability to produce taxol was improved from 314.07 microg/L (strain NCEU-1) to 418.24 microg/L (strain U04-5).

Ascomycota↗
PubMed2005

[Application of double-filtration plasmapheresis in major ABO-incompatible unrelated bone marrow transplantation].

OBJECTIVE: To evaluate the effect of double-filtration plasmapheresis (DFPP) in major ABO-incompatible unrelated allogenic bone marrow transplantation. METHODS: The red cell antibodies were removed by DFPP in 5 recipients to prevent hemolysis and pure red cell aplasia following major ABO-incompatible unrelated bone marrow transplantation. RESULTS: The isohemagglutinin titers of the 5 recipients were below 1:16 after DFPP with only one recipient developed transient mild acute hemolysis. Delayed hemolysis and pure red cell aplasia occurred in none of the cases and all recipients were completely engrafted. CONCLUSION: DFPP can effectively prevent hemolysis and pure red cell aplasia in recipients of unrelated bone marrow transplantation with major ABO-incompatibility.

ABO Blood-Group System↗
PubMed2005

[Application of flexible bronchoscopy in postoperative management of lung transplantation].

OBJECTIVE: To investigate the application of flexible bronchoscopy in the postoperative management of lung transplantation. METHODS: Four male patients with end-stage chronic obstructive pulmonary disease received examination with bronchoscope following the unilateral lung transplant for management of airway complications. One patient developed stenosis at tracheal anastomosis 2 months after transplantation and underwent balloon dilatation and endobronchial metallic stent placement. RESULTS: The 4 patients showed good recovery after transplantation with obviously improved pulmonary function and quality of life. CONCLUSION: Flexible bronchoscopy provides a valuable means for postoperative management of lung transplantation.

Bronchoscopy↗
PubMed2005

[Combination application of radiofrequency ablation in nasal operation].

OBJECTIVE: To investigate the clinical efficacy of radiofrequency ablation in treating the inferior turbinates hypertrophic and allergic rhinitis after septoplasty or nasal polypectomy. METHOD: Ninety-one patients with nasal septum deviation or nasal polyp with inferior turbinates hypertrophic and(or) allergic rhinitis were underwent septoplasty or nasal polypectomy. Sixty-two cases of 91 patients with inferior turbinates hypertrophic or allergic rhinitis underwent radiofrequency ablation, 29 cases did not. The preoperative and postoperative nasal obstructions were investigated by visual analogue scale (VAS). Allergic rhinitis symptoms were assessed by 1997s Haikou standard. RESULT: The nasal obstruction and allergic symptom of 62 patients who underwent radiofrequency ablation were improved in 3 months postoperatively. VAS improved from (89.5+/-8.7) % to (26.2+/-8.7) % (left side) and (90.3+/-10.5) % to (32.1+/-10.3) % (right side) (P < 0.01). In control group: VAS improved from (90.5+/-8.0) % to (39.2+/-8.9) % (left side) and (89.9+/-11.5) % to (48.1+/-8.1) % (right side) (P <0.01). However, the mean of postoperative nasal obstruction VAS in radiofrequency ablation group is significantly higher than that in control group (P <0.01). CONCLUSION: Combination application of radiofrequency ablation in nasal operation to cure the inferior turbinates hypertrophic and allergic rhinitis is a safe, effective and less traumatic method.

Adolescent↗
PubMed2005

[The impact of gender factor on the candidate gene study of essential hypertension].

OBJECTIVE: To study the impact of gender factor on the candidate gene study of essential hypertension (EH). METHODS: The polymerase chain reaction (PCR) was performed to analyze the ACE gene I/D polymorphism of hypertensive patients (50 men and 50 women) and normal controls (50 men and 50 women). The investigation was further focused on possible influence of sex proportion on the conclusion of this kind of research. RESULTS: The frequency of DD genotype in male hypertensive patients is significantly higher than that in male normal controls (chi(2) = 6.98, P = 0.004). The frequency of D allele in male EH group is significantly higher than that of male normal controls (chi(2) = 6.87, P = 0.009), while no significant difference was observed for II and ID genotype between male EH group and control group (P > 0.05). For female EH group and normal controls, there were no significant differences in frequency of genotype and allele (P > 0.05), the distribution ratio of DD genotype in male EH group is significantly different from that of female EH group (chi(2) = 4.06, P = 0.044). Furthermore, males with DD genotype in EH group had higher SBP and PP than that of males with II and ID genotype (P < 0.05). However, there was no significant difference in DBP in all three genotypes (P > 0.05). At the same time, there was no difference in SBP, DBP and PP (P > 0.05) between II and ID genotype in male EH group. In female hypertensive patients, there was no significant difference in SBP, DBP and PP between all three genotypes (P > 0.05). CONCLUSIONS: The relationship between DD genotype in male and EH (especially SBP and PP) is closer than any other genotype-EH relationships in both male and female. The gender factor, as a probable confounding factor, can affect many candidate gene studies of essential hypertension including ACE gene I/D polymorphism, and thus biases the conclusion.

Aged↗
PubMed2004

siRNAs targeting an intronic transposon in the regulation of natural flowering behavior in Arabidopsis.

Allelic variation in FLOWERING LOCUS C (FLC), a central repressor of flowering, contributes to natural differences in flowering behavior among Arabidopsis accessions. The weak nature of the FLC allele in the Ler accession is due to low levels of FLC RNA resulting, through an unknown mechanism, from a transposable element inserted in an intron of FLC. Here we show that the transposable element renders FLC-Ler subject to repressive chromatin modifications mediated by short interfering RNAs generated from homologous transposable elements in the genome. Our studies have general implications for the role of transposable elements in eukaryotic gene expression and evolution.

Arabidopsis↗
PubMed2004

The role of Plasmodium falciparum food vacuole plasmepsins.

Plasmepsins (PMs) are thought to have an important function in hemoglobin degradation in the malarial parasite Plasmodium falciparum and have generated interest as antimalarial drug targets. Four paralogous plasmepsins reside in the food vacuole of P. falciparum. Targeted gene disruption by double crossover homologous recombination has been employed to study food vacuole plasmepsin function in cultured parasites. Parasite clones with deletions in each of the individual PM I, PM II, and HAP genes as well as clones with a double PM IV/PM I disruption have been generated. All of these clones lack the corresponding PMs, are viable, and appear morphologically normal. PM II and PM IV/I disruptions have longer doubling times than the 3D7 parental line in rich RPMI medium. This appears to be because of a decreased level of productive progeny rather than an increased cell cycle time. In amino acid-limited medium, all four knockouts exhibit slower growth than the parental strain. Compared with 3D7, knock-out clone sensitivity to aspartic and cysteine protease inhibitors is changed minimally. These results suggest substantial functional redundancy and have important implications for the design of antimalarial drugs. The slow growth phenotype may explain why P. falciparum has maintained four plasmepsin genes with overlapping functions.

Amino Acids↗
PubMed2004

Loss of caveolin-1 polarity impedes endothelial cell polarization and directional movement.

The ability of a cell to move requires the asymmetrical organization of cellular activities. To investigate polarized cellular activity in moving endothelial cells, human endothelial cells were incubated in a Dunn chamber to allow migration toward vascular endothelial growth factor. Immunofluorescent staining with a specific antibody against caveolin-1 revealed that caveolin-1 was concentrated at the rear of moving cells. Similarly, monolayer scraping to induce random cell walk resulted in relocation of caveolin-1 to the cell rear. These results suggest that posterior polarization of caveolin-1 is a common feature both for chemotaxis and chemokinesis. Dual immunofluorescent labeling showed that, during cell spreading, caveolin-1 was compacted in the cell center and excluded from nascent focal contacts along the circular lamellipodium, as revealed by integrin beta1 and FAK staining. When cells were migrating, integrin beta1 and FAK appeared at polarized lamellipodia, whereas caveolin-1 was found at the posterior of moving cells. Notably, wherever caveolin-1 was polarized, there was a conspicuous absence of lamellipod protrusion. Transmission electron microscopy showed that caveolae, similar to their marker caveolin-1, were located at the cell center during cell spreading or at the cell rear during cell migration. In contrast to its unphosphorylated form, tyrosine-phosphorylated caveolin-1, upon fibronectin stimulation, was associated with the focal complex molecule phosphopaxillin along the lamellipodia of moving cells. Thus, unphosphorylated and phosphorylated caveolin-1 were located at opposite poles during cell migration. Importantly, loss of caveolin-1 polarity by targeted down-regulation of the protein prevented cell polarization and directional movement. Our present results suggest a potential role of caveolin polarity in lamellipod extension and cell migration.

Caveolae↗
PubMed2004

Quantifying anti-HBV effect of targeted ribonuclease by real-time fluorescent PCR.

AIM: To quantify the inhibition of HBV replication by targeted ribonuclease by using real-time fluorescent PCR. METHODS: Targeted ribonuclease was introduced into 2.2.15 cells by liposome-mediated transfection or HIV-TAT mediated protein transduction. Forty-eight hours after the transfection and 24 h after the transduction, supernatants of 2.2.15 cells were collected and HBV DNA in the supernatants was quantified by real-time fluorescent PCR with a commercial kit. RESULTS: HBV DNA concentrations in the supernatants of 2.2.15 cells transfected or transducted with targeted ribonuclease were 4.9+/-2.4 x 10(8) copies/L and 8.3+/-4.0 x 10(8) copies/L, respectively. Compared with controls, transfection or transduction of targeted ribonuclease reduced HBV DNA concentration in the supernatants of 2.2.15 cells by 90.4% and 90.1%, respectively (P<0.05). CONCLUSION: Targeted ribonuclease can inhibit HBV replication in 2.2.15 cells.

Cell Line, Tumor↗
PubMed2004

Method for the comparative glycomic analyses of O-linked, mucin-type oligosaccharides.

A method is presented for the direct relative quantitation of distinct O-linked mucin-type oligosaccharides. Mucin-type oligosaccharides are found in a host of tissues from anuran to humans. Because they are often associated with extracellular matrix, they play important roles in cell-cell recognition. Changes in glycosylation of O-linked oligosaccharides are associated with diseases such as cancer. In fertilization, they play an active role in sperm-egg recognition. We describe a method for observing changes in glycosylation of mucin-type oligosaccharides by incorporating deuterium in the release procedure. Oligosaccharides from two different sources are released separately by sodium tetrahydroborate and sodium tetradeuterioborate. The oligosaccharides are combined and separated into components by HPLC. By observing the ratio of deuterated and undeuterated species, changes in glycosylation are precisely quantified. This method is illustrated with mucin-type oligosaccharides from the egg jelly coat of the anuran Xenopus laevis.

Animals↗
PubMed2004

Translational autoregulation of thymidylate synthase and dihydrofolate reductase.

The folate-dependent enzymes, thymidylate synthase (TS) and dihydrofolate reductase (DHFR) are critical for providing the requisite nucleotide precursors for maintaining DNA synthesis and DNA repair. In addition to their essential roles in enzyme catalysis, these two enzymes have now been shown to function as RNA binding proteins. Using in vitro and in vivo experimental model systems, we have shown that the functional consequence of binding of TS protein to its own cognate mRNA, as well as binding of DHFR to its own DHFR mRNA, is translational repression. Herein, we review and update studies focusing on the translational autoregulatory control of TS and DHFR expression and discuss the molecular elements that are required for these specific RNA-protein interactions. Moreover, we present evidence showing that abrogation of these normal translational autoregulatory feedback mechanisms provides the molecular basis for the rapid development of cellular drug resistance.

Animals↗
PubMed2004

Effect of structure of PEO-PPO-PEO copolymers on reverse micelle formation induced by compressed CO2.

The micellization of PEO-PPO-PEO block copolymers in p-xylene has been studied in the presence of CO2. With the application of CO2, some copolymers with suitable molecular weights and EO ratios can form reverse micelles with critical micellization pressure up to 5.8 MPa. For the copolymers with the same length of PO block, higher EO ratios facilitate reverse micelle formation. For the copolymers with the same composition, higher molecular weight is favorable to form reverse micelles. With the suitable composition and molecular weight, the critical micelle pressure (CMP) of copolymers decreases with the increase in the lengths of PEO and PPO blocks due to the hydrophilic and folding effects, respectively. Both the EO ratios and the molecular weights are important for the formation of reverse micelle. The reverse micelle solution can solubilize water with W0 (molar ratio of water to EO segment) up to 3.3.

Journal Article↗
PubMed2004

Cutting edge: pulmonary immunopathology mediated by antigen-specific expression of TNF-alpha by antiviral CD8+ T cells.

Respiratory virus infection results in considerable pulmonary immunopathology, a component of which results from the host immune responses. We have developed a murine model to specifically examine the lung injury due to CD8(+) T cell recognition of an influenza hemagglutinin (HA) transgene on lung epithelium in the absence of replicating virus, after adoptive transfer. Lung injury is largely mediated by chemokines expressed by the epithelial cells upon T cell recognition mediated by TNF-alpha. To determine the critical source of TNF-alpha, HA-specific TNF(-/-) CD8(+) T cells were transferred into HA transgenic animals, and lung injury was not observed, though these T cells exhibited no defect in antiviral activity in vivo. This indicates that the initiating event in the injury process is Ag-specific expression of TNF-alpha by antiviral CD8(+) T cells upon recognition of alveolar epithelial Ag, and that the effector activities responsible for viral clearance may be dissociable from those resulting in immunopathology.

Adoptive Transfer↗
PubMed2004

BAK overexpression mediates p53-independent apoptosis inducing effects on human gastric cancer cells.

BACKGROUND: BAK (Bcl-2 homologous antagonist/killer) is a novel pro-apoptotic gene of the Bcl-2 family. It has been reported that gastric tumors have reduced BAK levels when compared with the normal mucosa. Moreover, mutations of the BAK gene have been identified in human gastrointestinal cancers, suggesting that a perturbation of BAK-mediated apoptosis may contribute to the pathogenesis of gastric cancer. In this study, we explored the therapeutic effects of gene transfer mediated elevations in BAK expression on human gastric cancer cells in vitro. METHODS: Eukaryotic expression vector for the BAK gene was constructed and transferred into gastric cancer cell lines, MKN-45 (wild-type p53) and MKN-28 (mutant-type p53). RT-PCR and Western Blotting detected cellular BAK gene expression. Cell growth activities were detected by MTT colorimetry and flow cytometry, while apoptosis was assayed by electronic microscopy and TUNEL. Western Blotting and colorimetry investigated cellular caspase-3 activities. RESULTS: BAK gene transfer could result in significant BAK overexpression, decreased in vitro growth, cell cycle G0/G1 arrest, and induced apoptosis in gastric cancer cells. In transferred cells, inactive caspase-3 precursor was cleaved into the active subunits p20 and p17, during BAK overexpression-induced apoptosis. In addition, this process occurred equally well in p53 wild-type (MKN-45), or in p53 mutant-type (MKN-28) gastric cancer cells. CONCLUSIONS: The data presented suggests that overexpression of the BAK gene can lead to apoptosis of gastric cancer cells in vitro, which does not appear to be dependent on p53 status. The action mechanism of BAK mediated apoptosis correlates with activation of caspase-3. This could be served as a potential strategy for further development of gastric cancer therapies.

Apoptosis↗