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Biomedical subjects

Jin Liu

Publications and source records attributed to Jin Liu.

At least 91 records · Page 5Linked to original sources
PubMed2004

Overexpression of cellular FLICE-inhibitory protein (FLIP) in gastric adenocarcinoma.

The aim of the present study was to investigate the prevalence of c-FLIP [cellular FLICE-inhibitory protein, where FLICE is Fas-associated death domain (FADD)-like interleukin-1beta-converting enzyme] expression in gastric adenocarcinoma and its possible implications for the progression of the cancer. Expression of c-FLIP in 48 gastric adenocarcinomas and their normal counterparts was analysed by reverse transcriptase PCR, Western blotting and immunohistochemistry. In situ cell apoptosis was detected by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling) assay. As a result, c-FLIP transcripts were constitutively expressed in gastric adenocarcinomas and their levels were significantly higher than those in matched normal tissues ( P < 0.01). Immunohistochemically, the c-FLIP protein was also found to be expressed in all gastric adenocarcinomas (48/48), and 68.8% (33/48) showed an intense immunostaining; in contrast, only 75% (36/48) of normal gastric mucosa showed positive staining and none of them immunostained intensely. The abundance of c-FLIP protein was significantly higher in carcinoma than in normal gastric mucosa (6.93 +/- 0.58 versus 3.19 +/- 0.26, P < 0.01) and showed a reverse correlation with apoptotic index in adenocarcinoma, but not in normal mucosa. In addition, abundance of c-FLIP was significantly associated with lymph node metastasis at both mRNA level ( P < 0.05) and protein level ( P < 0.01). Western-blot analysis showed that the expression levels of the long form of c-FLIP and the short form of c-FLIP in adenocarcinomas were 2.6-fold and 2.8-fold ( P < 0.01) higher than those in normal tissues respectively. However, no significant difference was found between the expression levels of the two isoforms in both adenocarcinomas or normal tissues. In conclusion, overexpression of c-FLIP is tumour specific, which may be one of the in vivo mechanisms by which tumour cells escape from apoptotic death during the malignant transformation, and plays an important role in lymph node metastasis of gastric adenocarcinoma, which ultimately contributes to the tumour progression.

Adenocarcinoma↗
PubMed2004

A novel approach to 3-D gaze tracking using stereo cameras.

A novel approach to three-dimensional (3-D) gaze tracking using 3-D computer vision techniques is proposed in this paper. This method employs multiple cameras and multiple point light sources to estimate the optical axis of user's eye without using any user-dependent parameters. Thus, it renders the inconvenient system calibration process which may produce possible calibration errors unnecessary. A real-time 3-D gaze tracking system has been developed which can provide 30 gaze measurements per second. Moreover, a simple and accurate calibration method is proposed to calibrate the gaze tracking system. Before using the system, each user only has to stare at a target point for a few (2-3) seconds so that the constant angle between the 3-D line of sight and the optical axis can be estimated. The test results of six subjects showed that the gaze tracking system is very promising achieving an average estimation error of under 1 degrees.

Eye↗
PubMed2004

The cloning and preliminarily functional analysis of the human neurotrimin gene.

Proteins of the immunoglobulin superfamily (IgSF) are involved in a variety of specific cell-cell interactions in the developing nervous system. To identify and characterize new members of this protein family in human nervous system, we screen the human fetal brain cDNA library and isolate a full-length cDNA clone which contains a 1032 bp open reading frame encoding a protein of 344 amino acids. Sequence analysis reveals that it is a glycoprotein comprised of three C2-like immunoglobulin domains and is anchored to the plasma membrane via a post-translationally attached glycosyl-phosphatidylinositol (GPI) moiety. The protein shows high sequence similarity to the rat Ntm (97%), so we term it human neurotrimin (NTM). Northern blot analysis reveals that (HUMAN)NTM has three different transcripts with the length of 3.2 kb, 4.0 kb and 9.0 kb respectively. It has a wider expression pattern than that of (RAT) Ntm. Notably, the expression of NTM in fetal brain is higher than that in mature brain and is stronger in nervous tumors than that in normal brain tissues. We insert an HA epitope tag between the third Ig-like domain of NTM and the site of GPI attachment, then construct it into the eukaryotic expression vector pcDNA3.1+/Zeocin. The pcDNA3.1-HA-NTM is transfected into the Chinese Hamster Ovary (CHO) cells. The results demonstrate that HA-NTM is expressed on the surface of CHO cells and could strengthen the aggregation of CHO-NTM cells.

Amino Acid Sequence↗
PubMed2004

[Effects of pregnancy and blood components on solubility of fluoride volatile anesthesia].

OBJECTIVE: To determine the effect of pregnancy on blood/gas partition coefficient (B/G) of volatile anesthetics and to evaluate the relation between B/G and blood component concentration. METHODS: Blood samples were obtained from four groups of fasting women: 8 nonpregnancies, 8 first-trimester pregnancies, 12 mid-trimester pregnancies, 12 third-trimester pregnancies. B/G of desflurane, isoflurane and halothane in each subject was measured by double equilibration technique. Red blood cell (RBC), hemoglobin concentration (Hb), hematocrit (HCT) and the serum concentration of cholesterol (Chol), triglyceride (TG), albumen (Alb), globulin (Glob) were measured. RESULTS: 1. There was no significant difference in B/G of desfluraneand and in B/G of halothane among the four groups. There was significant difference in B/G of isoflurane; the lowest B/G was in the mid-trimester and the highest B/G was in the third trimester of pregnancy. The trend direction of halothane among four groups was similar to that of isoflurane, although no significant difference was observed therein. 2. RBC, Hb and HCT showed statistically significant difference among the four groups, which decreased to the lowest level in the mid-trimester and came up slightly in the third trimester. There was statistically significant difference in Alb, A/G, TG and Chol among the four groups. Alb and A/G were the lowest and TG, Chol were the highest in the third-trimester of pregnancy. 3. There was a correlation between the serum TG and the B/G of halothane. The B/G of isoflurane correlated directly with serum TG and Hb. The B/G of desflurane correlated directly with Chol. CONCLUSION: The above findings indicated that pregnancy brought on alterations in the blood components and serum components, thus inducing the difference in B/G between the flaoride volatile anesthetics. During pregnancy, the B/G of isoflurane altered significantly more than that of halothane did, whereas no significant alteration in the B/G of desflurane was noted.

Adult↗
PubMed2004

[Dental occlusion and maxillofacial changes after correction of early crossbite with FR-III].

OBJECTIVE: To study the changes of the dental occlusion and the maxillofacial region after treatment with FR-III for crossbite in children in deciduous and mixed dentition phases. METHODS: Sixty-four children with crossbite in deciduous and mixed dentition phases were included in this study. Tooth models and Schuller's position and lateral head X-rays were measured before and after treatment with FR-III to study the changes in the three-dimensional structures of the dental occlusion and maxillofacial region. RESULT: The width of dental arch exhibited little changes after the treatment whereas the length of the maxillary dental arch was increased. The upper incisors grew in labial inclination and the condyle withdrew to its natural position. The relationship of maxillary and mandibular base bone was obviously improved after the treatment, which also promoted the lingual inclination of the lower incisiors and the decrease of the genial angle. The lower and posterior facial height was increased. CONCLUSION: FR-III readjusts the muscle function of oral and maxillofacial system and promotes normal development of the dental arch and jaw.

Activator Appliances↗
PubMed2004

Myocardial protection of warm cardioplegic induction on the isolated perfused rat heart model.

Myocardial protection through different cardioplegia approaches is an important issue for successful cardiovascular surgery. The objective of this prospective randomized study was to evaluate the effect of myocardial protection of warm (37 degrees C) and cold (6 degrees C) cardioplegic induction, respectively, using a Langendorff isolated rat heart perfusion model. Twenty-eight isolated rat hearts on the Langendorff perfusion model were randomly divided into two groups: group T (n = 14) received warm (37 degrees C) cardioplegic induction, followed by cold (6 degrees C) cardioplegia after ECG showed straight line; alternatively, group C (n = 14) received only cold cardioplegic induction. After undergoing ischemia for 80 min, both group T and group C received reperfusion with Krebs-Henseleit Buffer (KHB) for 40 min. An additional group A (n = 7) received KHB continuously for 120 min and served as the control group for the assessment of Na(+)/K(+)-ATPase activity. The coronary flow, concentration of creatine kinase (CK) in coronary effluent, and cardiac function were evaluated at different time periods. Na(+)/K(+)-ATPase activity was assessed at the end of reperfusion. The coronary flow, content of CK in coronary effluent, heart rate, dp/dtmax, and left ventricular peak pressure (LVPP) were significantly greater (p < .05) in group T than group C during the reperfusion period. The negative value of -dp/dtmax and left ventricular end-diastolic pressure (LVEDP) was significantly lower (p < .05) in group T than group C, during the reperfusion period. The Na(+)/K(+)-ATPase activity assessed at the end of reperfusion period was significantly higher (p < .05) in group A and group T than group C, while no significant difference (p = .13) was found between group T and group A. Compared with cold cardioplegic induction, warm cardioplegic induction provides superior myocardial protection by enhancing coronary flow, reducing myocardial injury, improving cardiac function, and preserving Na(+)/K(+)-ATPase activity.

Animals↗
PubMed2004

[Visualizing living fibroblast on co-cultured denture base resin by green fluorescent protein marker introduced into the cell].

Visualizing living cells growing on co-cultured biomaterials is ideal for material biocompatibility evaluation in vitro. In this experiment, mouse fibroblasts L929 were labeled by introducing the gene coding enhanced green fluorescent protein (EGFP) marker into the cells. Morphology as well as proliferation of labeled cells surrounding or on the surface of co-cultured denture base resin slides were observed by use of phase-contrast microscope and fluorescent microscope directly. It was found that residual methyl methacrylate (MMA) in the denture base resin exhibited transient cytotoxicity to fibroblasts and this transient cytotoxicity could be eliminated by pre-extracting the resin with ddH2O for a short time. This fact demonstrated that even slight cytotoxicity of materials could be detected through imaging of living cells near material or material touched. And it was suggested that imaging of living cells co-cultured with biomaterial is helpful to understanding biocompatibility of materials more accurately.

Acrylic Resins↗
PubMed2004

[Cloning of the genes related to inhaled anesthetic action in Drosophila melanogaster].

OBJECTIVE: To search new clues to reveal the action mechanism of inhaled anesthetics. METHODS: Three kinds of Drosophila melanogaster were used as studied models: the wild type strain (H), the sevoflurane-sensitive strain (S), and the sevoflurane-resistant strain (R). Differential display reverse transcriptional-polymerase chain reaction method was performed to examine the differentially expressed fragments between Drosophila induced with and without sevoflurane. Rapid amplification of cDNA ends (RACE) method was used to clone the full length cDNA from positive differentially expressed fragments. RESULTS: Thirty-one differentially expressed fragments were found between the two groups. Three fragments were identified as the positive differentially expressed fragments by Northern blot analysis. Two full-length cDNAs were cloned by RACE method, among which one was a 1.0 kb Drosophila calmodulin (CaM), located on Chr.2; the other was a 4.1 kb gene with unknown function (No.45), located on Chr.3. CONCLUSION: The two full-length cDNAs belong to the genes that related to anesthetic action pathway, which might participate in the regulation of cellular functions and signal transduction pathways. The two genes that we found should provide a novel way to study the mechanism of inhaled anesthetic action.

Anesthetics, Inhalation↗
PubMed2004

[The role of cyclooxygenase-2 and vascular endothelial growth factor-C in lymphatic metastasis of gastric cancer].

OBJECTIVE: It has been known that cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF)-C are closely related with the development of tumors. To investigate the expression of COX-2 and VEGF-C in gastric cancer and the correlation between them. METHODS: Sixty-four paraffin-embedded gastric cancer samples and 22 flesh gastric cancer samples were tested with using immunohistochemistry method and the reverse transcription-polymerase chain reaction technology respectively. RESULTS: The mean expressive density of COX-2 and VEGF-C mRNA in gastric cancer were both significantly higher than those in non-cancerous gastric mucosa (1.363 +/- 0.351 vs 0.763 +/- 0.304, 0.972 +/- 0.331 vs 0.314 +/- 0.215, P < 0.001). The positive rates of COX-2 and VEGF-C in 64 gastric cancer samples were 72% and 64% respectively. Their expression in the groups of lymph-node metastasis were higher than that of the non-lymph-node metastasis groups respectively (P < 0.05). Moreover, there was a close correlation between COX-2 and VEGF-C expression levels (P < 0.05). CONCLUSIONS: There are high COX-2 and VEGF-C expression in gastric cancer. Gastric tumor tissues that produce VEGF-C may have a higher lymphatic invasion and metastatic potential. COX-2 may participate in VEGF-C lymphangiogenic pathway and the high expression of them may play an important role in the lymphatic proliferation and spread in gastric cancer.

Adult↗
PubMed2003

Enlargement of high density lipoprotein in mice via liver X receptor activation requires apolipoprotein E and is abolished by cholesteryl ester transfer protein expression.

The factors involved in the generation of larger high density lipoprotein (HDL) particles, HDL1 and HDLc, are still not well understood. Administration of a specific synthetic liver X receptor (LXR) agonist, T0901317, in mice resulted in an increase of not only HDL cholesterol but also HDL particle size (Cao, G., Beyer, T. P., Yang, X. P., Schmidt, R. J., Zhang, Y., Bensch, W. R., Kauffman, R. F., Gao, H., Ryan, T. P., Liang, Y., Eacho, P. I., and Jiang, X. C. (2002) J. Biol. Chem. 277, 39561-39565). We have investigated the roles that apoE and CETP may play in this process. We treated apoE-deficient, cholesterol ester transport protein (CETP) transgenic, and wild type mice with various doses of the LXR agonist and monitored their HDL levels. Fast protein liquid chromatography and apolipoprotein analysis revealed that in apoE knockout mouse plasma, there was neither induction of larger HDL formation nor increase of HDL cholesterol, suggesting that apoE is essential for the LXR agonist effects on HDL metabolism. In CETP transgenic mice, CETP expression completely abolished LXR agonist-mediated HDL enlargement and greatly attenuated HDL cholesterol levels. Analysis of HDL particles by electron microscope and nondenaturing gel electrophoresis revealed similar findings. In apoE-deficient mice, LXR agonist also produced a significant increase in very low density lipoprotein/low density lipoprotein cholesterol and apolipoprotein B content. Our studies provide direct evidence that apoE and CETP are intimately involved in the accumulation of the enlarged HDL (HDL1 or HDLc) particles in mice.

Animals↗
PubMed2003

The COPI complex functions in nuclear envelope breakdown and is recruited by the nucleoporin Nup153.

Nuclear envelope breakdown is a critical step in the cell cycle of higher eukaryotes. Although integral membrane proteins associated with the nuclear membrane have been observed to disperse into the endoplasmic reticulum at mitosis, the mechanisms involved in this reorganization remain to be fully elucidated. Here, using Xenopus extracts, we report a role for the COPI coatomer complex in nuclear envelope breakdown, implicating vesiculation as an important step. We have found that a nuclear pore protein, Nup153, plays a critical role in directing COPI to the nuclear membrane at mitosis and that this event provides feedback to other aspects of nuclear disassembly. These results provide insight into how key steps in nuclear division are orchestrated.

ADP-Ribosylation Factors↗
PubMed2003

Comparative evaluation of immune response after laparoscopical and open total mesorectal excisions with anal sphincter preservation in patients with rectal cancer.

AIM: The study of immune response of open versus laparoscopical total mesorectal excision with anal sphincter preservation in patients with rectal cancer has not been reported yet. The dissected retroperitoneal area that contacts directly with carbon dioxide is extensive in laparoscopic total mesorectal excision with anal sphincter preservation surgery. It is important to clarify whether the immune response of laparoscopic total mesorectal excision with anal sphincter preservation (LTME with ASP) in patients with rectal cancer is suppressed more severely than that of open surgery (OTME with ASP). This study was designed to compare the immune functions after laparoscopic and open total mesorectal excision with anal sphincter preservation for rectal cancer. METHODS: This study involved 45 patients undergoing laparoscopic (n=20) and open (n=25) total mesorectal excisions with anal sphincter preservation for rectal cancer. Serum interleukin-2 (IL-2), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha) were assayed preoperatively and on days 1 and 5 postoperatively. CD3+ and CD56+ T lymphocyte count, CD3- and CD56+ natural killer cell (NK) count and immunoglobulin (IgG/IgM/IgA) were assayed preoperatively and on day 5 postoperatively. The numbers of CD3+ and CD56+ T lymphocytes and CD3- and CD56+ NK cells were counted using flow cytometry. An enzyme-linked immunosorbent assay (ELISA) was used for IL-2, IL-6 and TNFalpha determination. And IgG, IgM, and IgA were assayed using immunonephelometry. RESULTS: The demographic data of the two groups had no difference. The preoperative levels of CD3+ and CD56+ T lymphocyte count, CD3- and CD56+ NK count, serum IgG, IgM, IgA, IL-2, IL-6 and TNFalpha also had no significant difference in the two groups (P>0.05). The CD3+ and CD56+ T lymphocyte counts had no obvious changes after surgery in laparoscopic (d=-0.79 +/- 3.83%) and open (d=0.42 +/- 2.09%) groups. The CD3- and CD56+ NK counts were decreased postoperatively in both laparoscopic (d=-7.23 +/- 11.33%) and open (d=-9.21 +/- 13.93%) groups. The differences of the determined values of serum IgG, IgM and IgA on the fifth day after operation subtracted those before operation were -2.56 +/- 2.14 g/L, -252.35 +/- 392.94 mg/L, -506.15 +/- 912.24 mg/L in laparoscopic group, and -1.81 +/- 2.10 g/L, -282.72 +/- 356.75 mg/L, -252.20 +/- 396.28 mg/L in open group, respectively. The levels of IL-2 were decreased after operation in both groups. However, the levels of IL-6 were decreased after laparoscopic surgery (d1=-23.14 +/- 263.97 ng/L and d5=-40.08 +/- 272.03 ng/L), and increased after open surgery (d1=27.38 +/- 129.14 ng/L and d5=21.67 +/- 234.31 ng/L). The TNFalpha levels were not elevated after surgery in both groups. There were no significant differences in the numbers of CD3+ and CD56+ T lymphocytes and CD3- and CD56+ NK cells, the levels of IgG, IgM, IgA, IL-2, IL-6 and TNFalpha between the two groups (P>0.05). CONCLUSION: There are no differences in immune responses between the patients having laparoscopic total mesorectal excision with anal sphincter preservation and those undergone open surgery for rectal cancer.

Adult↗
PubMed2003

[Study on rabbit mesenchymal stem cells differentiation to the adipogenic or osteogenic lineage in vitro].

Rabbit bone marrow-derived mesenchymal stem cells(MSCs) are multipotent. We studied the adipogenic and osteogenic differentiation potent using adipogenic supplement (AS) or osteogenic supplement (OS) in vitro. Specific markers of this induced adipogenic and osteogenic lineage were identified. The findings showed that the rabbit MSCs are capable of differentiating into adipogenic and osteogenic lineages spontaneously. On the 21st day, approximately 75% rabbit MSCs were induced to adipogenic or osteogenic cells in medium containing AS or OS, respectively. These results demonstrated that the differentiation of MSCs could be regulated in vitro. The underlying molecular mechanisms of adipogenic or osteogenic differentiation await elucidation.

Adipose Tissue↗
PubMed2003

[Expression of nm23 genes in acute myeloid leukemia and its clinical significance].

OBJECTIVE: To explore nm23 gene mRNA expression and its clinical significance in acute leukemias (AML). METHODS: The levels of nm23-H1 and nm23-H2 transcripts in 22 patients with acute myeloid leukemia (AML), 9 AML in complete remission (AML-CR), 12 acute lymphoblastic leukemia (ALL) and 4 chronic myeloid leukemia in chronic phase (CML-CP) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: The expression of nm23-H1 in AL especially in AML-M4 and AML-M5 was significantly higher than that in normal blood cells. An analysis of correlation between nm23 expression and clinicopathological parameters showed that increased nm23-H1 mRNA levels were associated with some poor-prognostic factors such as extramedullary infiltration, high white blood cell count (WBC), high lactate dehydrogenase (LDH) activity and high CD(7) expression, while inversely correlated with t(8; 21) and t(15; 17) which had a good-prognostic effect. The expression of nm23-H1 in AML patients in CR was significantly decreased compared with those untreated. CONCLUSION: nm23-H1 was overexpressed in AL, especially in AML-M4 and AML-M5. High expression of nm23-H1 may be a poor prognostic factor.

Adult↗
PubMed2003

[Biological characteristics of human umbilical artery smooth muscle cells cultured in vitro and the preestablishment of immortalized cell line].

OBJECTIVE: To establish the best primary and propagated culture approach of the human umbilical artery smooth muscle cells (HUASMC) and immortalized the primary cells. METHODS: The primary culture of HUASMC was performed using the primary-explant method, and the effects on the cells' growth characteristic by different culture mediums were conducted. Primary cultures of HUASMC derived from normal human umbilical arteries were transfected with recombination plasmid containing human telomerase reverse transcriptase (hTERT) open reading frame. The transfected HUASMC was analyzed for cell biological characteristics, and growth characteristics, and specific alpha-actin. RESULTS: Highly purified primary HUASMC were gained and could be propagated about 10 population doublings (PD). After PD 4, the cells lost the proliferation ability gradually. However, the transfected HUASMC could be propagated at least 20 population doublings and could express specific alpha-actin. CONCLUSION: The hTERT transfected HUASMC could keep the basic biological characteristic of smooth muscle cells and prolonged life span at least 20 PD. It might be a good cell model for the study of cardiovascular disease, myoma of uterus and chronic graft disfunction. It might also bring the hope to engineered vascularization in the future.

Cell Line↗
PubMed2002

Kinetics of etomidate actions on GABA(A) receptors in the rat spinal dorsal horn neurons.

Electrophysiological properties of etomidate (ET)-induced current (I(ET)) at different concentrations and effects of ET at clinically relevant concentrations (1-10 microM) on postsynaptic GABA(A) receptor function were investigated using whole-cell patch-clamp technique in mechanically dissociated rat spinal dorsal horn neurons. The results showed that ET actions were concentration-dependent: low concentrations (10 microM) of ET potentiated GABA-activated current (I(GABA)), slowed activation, desensitization and deactivation of GABA(A) receptors; moderate concentrations (10-1,000 microM) of ET directly activated and desensitized GABA(A) receptors; high concentrations (>1,000 microM) of ET produced an inhibitory effect on I(ET). In addition, ET prolonged the duration of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) in the mechanically dissociated rat dorsal horn neurons. These results suggest that general anesthetics-induced changes at spinal level could significantly contribute to analgesia and general anesthesia.

Anesthetics, Intravenous↗
PubMed2002

[Properties of whole-cell potassium currents in mechanically dissociated Drosophila larval central neurons].

By electrophysiological methods, cultured Drosophila embryonic and larval central neurons have been widely used to study ion channels, neurotransmitter release and intracellular message regulation. Voltage-activated K(+) channels play a crucial role in repolarizing the membrane following action potentials, stabilizing membrane potentials and shaping firing patterns of cells. In this study, a mechanical vibration-isolation system was used to produce a sufficient number of acutely dissociated larval central neurons, of which the majority were type II neurons (2~5 microm in diameter). Using patch clamp technique, the whole-cell K(+) currents in type II neurons were characterized by containing a transient 4-AP-sensitive current (I(A)) and a more slowly inactivating, TEA-sensitive component (I(K)). According to their kinetic properties, five types of whole-cell K(+) currents were identified. Type A current exhibited primarily fast transient K(+) currents that activated and inactivated rapidly. The majority of the neurons, however, slowly inactivated K(+) currents with variable inactivation time course (type B current). Type C current, being present in a small number of the cells, was mainly composed of noninactivating components. Some of the neurons expressed both transient and slow inactivating components, but the slowly inactivating components could reach more than 50% of the peak current (type D current). Type E current showed distinct voltage-dependent activation properties, characterized by its bell-shaped activation curve. Type E current was inhibited by application of Ca(2+)-free solution or 0.1 mmol/L Cd(2+). Moreover, this novel current ran down much more rapidly than other types. These results indicate that different K(+) channels, which have different kinetic and pharmacological properties, underlie the whole-cell K(+) currents in type II neurons of Drosophila larval central nervous system.

Action Potentials↗