Biomedical subjects

Feng Liu

Publications and source records attributed to Feng Liu.

At least 73 records · Page 4Linked to original sources

PubMed2006

Proteome analysis of human liver carcinoma Huh7 cells harboring hepatitis C virus subgenomic replicon.

Chronic infection by hepatitis C virus (HCV) is closely correlated with serious liver diseases. Although considerable progress has been made during recent years, the mechanism of replication and pathogenesis of HCV infection are still elusive. We have applied proteomic techniques in this work to globally analyze the protein expression profiles of a human liver cell lines Huh7 in absence and presence of HCV replication, aiming at elucidating the components of HCV replication and the cellular responses to HCV replication. The protein mixtures of three subcellular fractions from Huh7 and Huh7-HCV were separated by 2-DE under various pH gradients. Differentially expressed spots were identified by MALDI-TOF MS, followed by database searching. A total of 179 comparative proteins were identified unambiguously, including proteins associated with host cytoskeleton, intracellular traffic, oxidative and ER stress, proteasome degradation, translation, apoptosis, proliferation, etc. Host proteins known to interact with HCV proteins, such as HSP27, alpha-actinin, nucleolin and eukaryotic initiation factor 4A-I, were elevated in Huh7-HCV cells. Our study provides the global information of proteomic alteration of Huh7 cells in the presence of HCV replication and the clues for further understanding of the mechanism of HCV replication and pathogenesis.

Carcinoma, Hepatocellular↗

PubMed2006

The effects of jet cavitation on the growth of Microcystis aeruginosa.

Different operating factors of jet cavitation method affecting one of cyanobacterial's (Microcystis aeruginosa) growths were investigated. The inhibition on M. aeruginosa growth by the jet cavitation method depended strongly on the hydraulic characteristics of cavitation tube, inlet pressure, cavitation number, light and different algae concentrations. The inhibitive efficiency of 64.58% in field water sample was obtained by this method. Moreover, the ultrastructural changes of M. aeruginosa before and after treatment were observed by the transmission electron microscope (TEM). The changes of UV-Visible spectra further demonstrated the inhibitive behaviors of jet cavitation on the growth of M. aeruginosa. The experimental results showed that jet cavitation method was a potential physical technology that could effectively inhibit the growth of M. aeruginosa.

Biomass↗

PubMed2006

Generation of three-dimensional hepatocyte/gelatin structures with rapid prototyping system.

Using rapid prototyping technology, three-dimensional (3D) structures composed of hepatocytes and gelatin hydrogel have been formed. This technique employs a highly accurate 3D micropositioning system with a pressure-controlled syringe to deposit cell/biomaterial structures with a lateral resolution of 10 microm. The pressure-activated micro-syringe is equipped with a fine-bore exit needle for which a wide variety of 3D patterns with different arrays of channels (through-holes) were created. More than 30 layers of a hepatocyte/gelatin mixture were laminated into a high spacial structure using this method. The laminated hepatocytes remained viable and performed biological functions in the construct for more than 2 months. The rapid prototyping technology offers potential for eventual high-throughout production of artificial human tissues or organs.

Animals↗

PubMed2006

CtIP activates its own and cyclin D1 promoters via the E2F/RB pathway during G1/S progression.

Cell cycle progression from G(1) to S phase is mainly controlled by E2F transcription factors and RB family proteins. Previously we showed that the presence of CtIP is essential for G(1)/S transition in primary mouse blastocysts, as well as in NIH 3T3 cells. However, how CtIP executes this function remains to be elucidated. Here we show that in NIH 3T3 cells the expression of CtIP is regulated by the E2F/RB pathway during late G(1) and S phases. The presence of wild-type CtIP, but not the E157K mutant form, which failed to interact with RB, enhanced its own promoter activity. Chromatin immunoprecipitation analysis indicated that the recruitment of CtIP to its promoter occurs concomitantly with TFIIB, a component of the RNA polymerase II complex, and with dissociation of RB from the promoter during late G(1) and G(1)/S transition. Similar positive regulation of cyclin D1 expression by CtIP was also observed. Consistently, cells expressing the CtIP(E157K) protein alone exhibited growth retardation, an increase in the G(1) population, and a decrease in the S-phase population. Taken together, these results suggest that, contrary to the postulated universal corepressor role, CtIP activates a subset of E2F-responsive promoters by releasing RB-imposed repression and therefore promotes G(1)/S progression.

Animals↗

PubMed2006

Importance of head diameter, clearance, and cup wall thickness in elastohydrodynamic lubrication analysis of metal-on-metal hip resurfacing prostheses.

The main design features of metal-on-metal (MOM) hip resurfacing prostheses in promoting elastohydrodynamic lubrication were investigated in the present study, including the femoral head diameter, the clearance, and the cup wall thickness. Simplified conceptual models were developed, based on equivalent uniform wall thicknesses for both the cup and the head as well as the support materials representing bone and cement, and subsequently used for elastohydrodynamic lubrication analysis. Both typical first- and second-generation MOM hip resurfacing prostheses with different clearances and cup wall thicknesses were considered with a fixed large bearing diameter of 50 mm, as well as a 28 mm diameter MOM total hip replacement bearing for the purpose of comparison. The importance of the head diameter and the clearance in promoting elastohydrodynamic lubrication was confirmed. Furthermore, it was also predicted that a relatively thin acetabular cup in the more recently introduced second-generation MOM hip resurfacing prostheses would be capable of improving elastohydrodynamic lubrication even further.

Acetabulum↗

PubMed2006

Mitochondria-regulated death pathway mediates (DIPP-L-Leu)2-L-LysOCH3-induced K562 cells apoptosis.

(DIPP-L-Leu)2-L-LysOCH3 is a diisopropylphosphoryl dipeptide which is known to induce apoptosis of human leukemia K562 cells. The molecular and cellular mechanisms involved in this process remain to be clarified. Herein, we show that (DIPP-L-Leu)2-L-LysOCH3-induced apoptosis is associated with cytosolic accumulation of cytochrome c, sustained loss of mitochondrial transmembrane potential (MMP), transient generation of reactive oxygen species (ROS) and elevation of intracellular Ca2+ concentration. A specific caspase assay reveals an increase in caspase-9 and caspase-3 activity but no change in caspase-8 activity. Immunofluorescence analysis indicates that (DIPP-L-Leu)2-L-LysOCH3 induced upregulation of pro-apoptotic Bax and downregulation of anti-apoptotic Bcl-2 and Bcl-x(L). These results suggest that the mitochondria-regulated death pathway mediates (DIPP-L-Leu)2-L-LysOCH3-induced K562 cells apoptosis.

Apoptosis↗

PubMed2006

A novel recently evolved gene C19orf24 encodes a non-classical secreted protein.

Secreted proteins play important roles in many crucial biological processes, and can be new agents or targets for drug therapies. Here, we report on the isolation and characterization of a novel human non-classical secreted protein which is encoded by the hypothetical gene C19orf24 (chromosome 19 open reading frame 24). It has no signal peptide, but can still secrete extracellularly despite the presence of the inhibitor brefeldin A (BFA), proving its non-classical secreted protein status. Via subcellular localization using C19orf24 in vivo and transfected pEYFP-Golgi plasmid in Hela cells, C19orf24 was shown not to co-localize in the Golgi apparatus, which suggested that it secretes via a new and unknown pathway. Deglycosylation analysis with PNGase F verified that it has no N-glycosylation modification sites. Via the reverse transcription-PCR method, it was found to be expressed only in the human liver, and preferentially in normal tissue. In addition, C19orf24 was shown to be a recently evolved gene, found only in Homo sapiens and Pan troglodytes. By calculating its synonymous and non-synonymous substitution rate (d (S)/d (N)), we found that it experienced a purifying selection, which suggests that C19orf24 may have a special, irreplaceable biological function in the human organism.

Amino Acid Sequence↗

PubMed2006

[Immunophenotypic features in leukemia of NK cell series].

The aim was to investigate the immunophenotypes of NK series leukemia. Immunophenotypes of 297 cases of acute leukemia (AL) were measured by flow cytometry, and these immucopenotypic features were analyzed. The results showed that 43 out of 297 cases of AL (14.5%) were CD56 positive. 6 cases were NK series leukemia and 37 cases were acute myelogenous leukemia with CD56 expressed. One patient has been diagnosed as myeloid/NK cell precursor acute leukemia, two patients were blastic NK cell leukemia, one was supposed to be NK-like T-cell lymphoma/leukemia, while another one was large granular lymphocyte leukemia (LGLL). It is concluded that almost all of CD56 positive leukemia were acute myelogenous leukemia with CD56 expressed. The immunophenotypes of NK series leukemia were antigens from hematopoietic stem cells to T/NK progenitor cells with meyloid antigen positive, and through NK progenitors to mature NK cells. The immunophenotypes of heterogeneous NK leukemia cells are different, that should be carefully distinguished.

Adolescent↗

PubMed2006

A preoperative and intraoperative predictive model of prolonged intensive care unit stay for valvular surgery.

BACKGROUND AND AIM OF THE STUDY: In developing countries, the costs of intensive care unit (ICU) stay are very high for patients after valve surgery. In addition, patients with a prolonged ICU stay have a poor prognosis compared to those with a short ICU stay. The study aim was to develop a specific risk model and to use a logistic EuroSCORE model to predict prolonged ICU stay after valve surgery. METHODS: A total of 507 consecutive patients undergoing valve surgery were studied using univariate and multivariate analyses. Prolonged ICU stay was defined as five days or more. Stepwise logistic regression analysis was used to identify the risk factors for prolonged ICU stay. These variables were then used to calculate a prognostic score (S) and a predicted probability (P) for prolonged ICU stay. A receiver operating characteristic (ROC) curve was calculated to measure the prognostic value of the new risk model and logistic EuroSCORE model. Sensitivity and specificity analysis were used for evaluation. RESULTS: Multivariate logistic regression analysis showed that age > or = 65 years, left ventricular ejection fraction (LVEF) < or = 50%, cardiothoracic ratio (CTR) > or = 0.68, previous cardiac surgery, maximal voluntary ventilation (MVV) observed/predicted < 71% and repeat cardiopulmonary bypass (CPB) during surgery were risk factors. Mitral valve surgery reduced the risk of prolonged ICU stay. Observed probabilities compared well with predicted probabilities. The ROC curve produced an area under the curve (AUC) value of 0.81 for prolonged ICU stay. Based on predicted probability, patients were classified as low-risk (0 < or = P < 10%), intermediate-risk (10% < or = P < 20%), high-risk (20% < or = P < 40%) and very high-risk (> or = 40%) groups. A P-value > or = 40% was used as a cut-off point for the prognostic test. The specificity of this test was 97%, sensitivity 32%, positive predictive value 62%, negative predictive value 89%, positive likelihood ratio 10.67, and negative likelihood ratio 0.70. The ROC curve of a logistic EuroSCORE model gave an AUC value of 0.66 for prolonged ICU stay. CONCLUSION: The study results showed that individual patients undergoing valve surgery could be stratified according to their risk factors for prolonged ICU stay. High-risk patients may require more careful preoperative and postoperative management to reduce postoperative mortality, morbidity, the length of ICU stay, and therefore the cost of valve surgery.

Cardiac Surgical Procedures↗

PubMed2006

[Improving the ways to isolate, cultivate and identify rat Kupffer cells].

OBJECTIVE: Kupffer cells (KCs) are resident macrophages in the liver. Because the densities and sizes of KCs show a significant overlap with other sinusoidal cells, it is difficult to separate and purify them. We aim to find an improved procedure that could optimize the method for isolation of highly purified rat Kupffer cells. METHODS: In ex vivo rat liver perfusion with pronase E and collagenase IV, density gradient centrifugation by Histodenz and selective attachment of Kupffer cells were used to isolate them. Cell proliferation and morphological characterization were studied under light phase-contrast microscopes; KCs were also studied with transmission electron microscopy and scanning electron microscopy using standard techniques. Immunocytochemistry was used to detect the expression of ED2 CD163 and lysosome associated membrane protein 2 (LAMP2). Phagocytosis of latex-beads by KCs was also studied. RESULTS: The yield rate of KCs was 5 x 10(7) and the KCs viability exceeded 98%. The purity of KCs identified by ED2 was higher than 98%, and over 99% of the collected KCs were LAMP2 positive. CONCLUSION: In the future this simple, stable and effective method of collecting highly purified Kupffer cells is expected to help in further studies.

Animals↗

PubMed2006

[Measurement of molecular vibrational temperature in dielectric barrier discharge in argon/air at atmospheric pressure].

Vibrational temperature of N2 (C 3IIu) molecules in dielectric barrier discharge (DBD) in argon/air at atmospheric pressure, in which the water electrodes were employed, was measured by using a method of spectrum diagnosis. Emission spectral lines of the N2 second positive band system(C 3IIu --> B 3IIg) and the sequences of vibrational bands with deltav = -1, deltav = -2 and deltav = -3 were used in the calculation. The experiment results show that the molecular vibrational temperature of N2 is in the range from 1 938 K to 2 720 K, and it increases almost linearly with increasing the air content in gas mixture. These results are of great importance to the study of plasma dynamics of DBD.

English Abstract↗

PubMed2006

[The preliminary research of 3D-reconstruction of lacrimal sac under computer].

OBJECTIVE: To explore the application of 3D-reconstruction of lacrimal sac under computer. METHOD: To the 3D model of lacrimal passage was reconstructed with CT scanning. RESULT: The anatomy of lacrimal passage could be displayed with 3D-reconstruction under computer and the relation between lacrimal sac and the axilla of the middle turbinate could be observed and measured freely. CONCLUSION: The technology of 3D-reconstruction under computer is greatly valuable in the anatomic research of lacrimal sac.

Adult↗

PubMed2006

[The use of CAD/CAM system with zirconia in modern prosthodontics].

Computer assisted design/computer assisted machining (CAD/CAM) technology has received considerable clinical and research interest from modern dental practices as a means of delivering all-ceramic restorations. Up to now the CAD/CAM system with zirconia has the highest fracture strength in all all-ceramic materials, and consistently enabled the most esthetic, lifelike reproduction of natural dentition. They have been widely received by both dentists and patients. The CAD/CAM system with zirconia is indicated for crowns and bridges in natural teeth or implants and telescope dentures, the CAD/CAM with zirconia can be placed anywhere in the mouth, and can replace the porcelain crowns and bridges for single crown and bridges less than 6 units. This paper described the techniques of CAD/CAM system with zirconia in fabrication of crowns, bridges, telescope dentures and implant dentures with colored illustrations.

Computer-Aided Design↗

PubMed2006

Proteomic analysis of a highly metastatic gastric cancer cell line using two-dimensional differential gel electrophoresis.

Stomach cancer is still a major cause of death in Asian people despite a complete cure after the resection of early cancers, mainly because peritoneal dissemination is difficult to treat. In the present study, we used two-dimensional differential gel electrophoresis (2-D DIGE) to identify specific proteins differentially expressed between a highly metastatic stomach cancer cell line MKN-45-P and its parental cell line MKN-45. We detected 27 protein spots in at least 2 of 3 experiments which showed statistically significant differences in abundance. All 27 protein spots were identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) and database-searching software. A proteomic analysis revealed 13 different proteins with some isoforms sharing different biochemical characteristics, and that 8 proteins were up-regulated, and 5 were down-regulated. The 13 proteins were mainly involved in protein synthesis (transfer RNA synthetase), metabolism (flavoprotein subunit, pyruvate kinase, adenylate kinase), receptor and signal transduction (annexins I and A2), the cytoskeleton (keratin 5, cytokeratin 8) and cell cycling (ts11). These results suggested that a proteomic approach including 2-D DIGE would be an efficient way to identify the proteins responsible for specific biological functions. Moreover, these observations might be novel findings leading to the prediction of postoperative peritoneal recurrence.

Cell Line, Tumor↗

PubMed2006

[Endonasal anatomy of lacrimal sac and its clinical significance in dacryocystorhinostomy].

OBJECTIVE: To explore the intranasal surface localization of the lacrimal sac in endoscopic dacryocystorhinostomy. METHODS: Fifteen adult cadavers (30 sides) were studied, the data of projection position of the lacrimal sac on the lateral wall of nasal cavity were measured. RESULTS: In 2/3 cadavers, the lacrimal sac is located above the axilla of the middle turbinate, and 1/3 lies below it. A majority of the lacrimal sac (2/3) are located below the entry point of the common lacrimal canaliculus, about 1/3 lies above it. Inner canthal ligament projects on the middle of the lacrimal sac, almost equal to the level of common lacrimal canaliculus. Thirty-two cases (thirty-nine sides) of chronic dacryocystitis were followed-up > 6 months after operation. Thirty-five sides were cured, 2 sides improved and 2 sides ineffective. The cure rate was 89.8%, improve rate 5.1% and ineffective rate 5.1%, respectively, and the total effective rate was 94.9%. CONCLUSIONS: The central position of dacryocystorhinostomy should be 0.2 cm above the front of the axilla of the middle turbinate, to make an curved mucous membrane incision 0.8 cm above and 0. 4 cm below the front of the axilla of the middle turbinate and bone ostium about 1.2 cm x 1.0 cm. It is the best position in endoscopic dacryocystorhinostomy. Locating the inner canthal ligament with a bayonet type forceps to find the projection of lacrimal sac is also a simple and easy method.

Adult↗

PubMed2006

[Preventing recurrent laryngeal nerve lesions by anastomosing it during thyroid surgery].

OBJECTIVE: To study how to prevent recurrent laryngeal nerve (RLN) lesions by anastomosing it during thyroid surgery. METHOD: In the present study 517 patients with thyroid diseases underwent thyroid surgery from January 1993 to May 2005, with RLNs of 163 cases (187 sides, A group) anatomized and RLNs of 354 cases (438 sides. B group) not anatomized. The RLN in B group were protected generally during thyroid surgery. RLNs of A group were anatomized partly or totally. RESULT: (1) In A group RLNs of 123 cases were partly anatomized and 64 totally. None of all RLNs was injuried. (2) B group 3 sides of 3 cases of all RLNs was injuried. The rate of RLN's lesion is 0.7%, which is significantly higher in A group than in B group. CONCLUSION: Anastomosing RLN during thyroid surgery may prevent its lesions. The length of anatomized RLN must vary with the area and position of thyroid pathological changes. The RLN needn't be anatomized in these patients with the benign thyroid pathological changes which is far away trachea-oesophagus channel.

Adult↗

PubMed2005

"New"-clear functions of PDK1: beyond a master kinase in the cytosol?

Activation of cytosolic phosphoinositide-3 kinase (PI-3K) signaling pathway has been well established to regulate gene expression, cell cycle, and survival by feeding signals to the nucleus. In addition, strong evidences accumulated over the past few years indicate the presence of an autonomous inositol lipid metabolism and PI-3K signaling within the nucleus. Much less, however, is known about the role and regulation of this nuclear PI-3K pathway. Components of the PI-3K signaling pathway, including PI 3-kinase and its downstream kinase Akt, have been identified at the nuclear level. Consistent with the presence of a complete PI-3K signaling pathway in the nucleus, we have recently found that phosphoinositide-dependent kinase 1 (PDK1), a kinase functioning downstream of PI-3K and upstream of Akt, is a nucleo-cytoplasmic shuttling protein. In the present review, we update our current knowledge on the regulatory mechanisms and the functional roles of PDK1 nuclear translocation. We also summarize some of the kinase-independent activities of PDK1 in cell signaling.

3-Phosphoinositide-Dependent Protein Kinases↗

PubMed2005

[Granulocyte colony-stimulating factor-mobilized autologous bone marrow stem cells promote the liver regeneration of partial liver transplant: an experiment with rats].

OBJECTIVE: To investigate the effects of granulocyte colony-stimulating factor (G-CSF)-mobilized autologous bone marrow stem cells on the liver regeneration of partial liver transplant. METHODS: A 50% partial liver transplantation model as established by transplanting parts of the liver of female rats to the male rats with the equal weights that had had parts of their livers resected. Then the transplanted male rats were randomly divided into 3 equal groups: G-CSF + PLTx group that was injected hypodermically with recombinant human G-CSF (rhG-CSF) daily for 5 days and then underwent liver resection and 50% partial liver transplantation (PLTx); PLTx + G-CSF group that underwent PLTx and 3 hours after the transplantation received injection of rhG-CSF daily for 5 days, and PLTx control group that underwent PLTx and 3 hours later received injection of normal saline daily for 5 days. One, 3, 5, 7, and 14 days after the PLTx blood samples and livers were collected from 6 rats from each group, and one hour before the liver was taken bromodeoxyuridine (BrdU) was injected intraperitoneally to be integrated into the synthesis of DNA in the liver cells. Immunohistochemistry was used to detect the CD34 and BrdU-positive cells. In situ hybridization was used to detect the sry (sex-determining region) gene so as to determine the origin of the proliferating cells in the transplanted liver. RESULTS: The 14-day survival rate of the G-CSF + PLTx group was 90%, significantly higher than those of the G-CSF + PLTx (60%) and PLTx group (50%) (both P < 0.05) with a significant difference between the latter 2 groups too (P < 0.05). The mitosis index of liver cells 3 days after the transplantation of the PLTx + G-CSF group was 30% +/- 5%, significantly higher than those of the G-CSF + PLTx group (24% +/- 7%) and PLTx group (24% +/- 6%) (both P < 0.05) without a significant difference between the latter 2 groups. The rate of BrdU-positive cells of the PLTx + G-CSF group was 42% +/- 6%, significantly higher than those of the G-CSF + PLTx group (38% +/- 4%) and PLTx group (34% +/- 8%) (both P < 0.05). The transplantation the mitosis index and rate of BrdU-positive cells decreased since the 7th days after transplantation in all 3 groups, however, with the same relationship among them. The numbers of CD34(+) cell around the portal area of the 2 G-CSF groups increased since the 3rd day after transplantation in comparison with the PLTx group, was the highest on the 3rd day for the G-CSF + PLTx group, and continued to increase in the PLTx + G-CSF group. Since the 3rd day after transplantation, sry-positive cells were seen in the hepatic sinusoid and portal area in the 2 G-CSF groups, and were rarely seen in the PLTx group. CONCLUSION: G-CSF treatment after 50% PLTx significantly promotes liver regeneration and ameliorates the liver damage, thus raising the survival rate.

Animals↗