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Biomedical subjects

X Liu

Publications and source records attributed to X Liu.

At least 379 records · Page 21Linked to original sources
PubMed2001

Comparison of prevalence, cost, and outcomes of a combination of salmeterol and fluticasone therapy to common asthma treatments.

OBJECTIVES: To compare a combination of salmeterol and fluticasone with common asthma pharmacologic regimens used in real-world clinical practice, and to evaluate the associated costs and outcomes of care. STUDY DESIGN: Cross-sectional examination of medical and pharmacy claims. METHODS: The study population included 33,939 adult asthmatics (at least 12 years of age) continuously enrolled in 1 of 4 participating health plans for the 6-month study period. Every subject was in 1 of 10 different pharmacotherapy treatment groups. Univariate and multivariate analyses were used to compare the rates and costs of pharmaceutical prescriptions and medical care services between patients on salmeterol plus fluticasone and patients with other pharmacologic therapies. RESULTS: About 60.4% of the patients were on single controllers; the balance was on short-acting beta 2-agonists alone (23%) or double controllers (16.8%). The average overall cost of asthma care was approximately $228 per patient over the 6 months of the study. Pharmaceutical cost was the major cost driver, which was significantly lower for single-controller (mean = $134) than for double-controller therapies (mean = $325). However, total costs were $50-$200 lower (P < .029) for patients on salmeterol plus fluticasone and inhaled steroids plus mast cell stabilizing agents than for those on other double controllers. CONCLUSIONS: Single-controller regimens and short-acting beta-agonists were less costly than double-controller regimens. Within the double-controller groups, salmeterol plus fluticasone appeared to be less costly than other double controllers, except inhaled steroids plus mast cell stabilizing agents.

Adult↗
PubMed2001

[Linkage disequilibrium analysis of chromosome 22 and schizophrenia in a Chinese population].

OBJECTIVE: To explore the molecular genetic relations of chromosome 22 and schizophrenia and locate the susceptibility gene of schizophrenia. METHODS: Six dinucleotide tandem repeat loci on chromosome 22 were chosen to analyze 126 affected sib-pair nuclear families of schizophrenia in Chinese population by fluorescent labeled auto-mated genotyping and transmission/ disequilibrium test(TDT). RESULTS: The TDT-chi square value of IL2Rbeta was 25.30(P=0.01), which suggests there is linkage disequilibrium between IL2R beta and schizophrenia. The P vaules of the other five loci (D22S944, D22S264, D22S303, D22S278 and CYP2D6) were greater than 0.05. CONCLUSION: A susceptive gene of schizophrenia may be located in IL2Rbeta locus or adjacent region.

Chromosomes, Human, Pair 22↗
PubMed2001

Changes in and effective factors of microtubule-associated protein 2 in traumatic neurons.

OBJECTIVE: To investigate alterations in the microtubule-associated protein 2 (MAP-2) of neurons in Wistar rats and the effect of nimodipine (Nim), D-2-amino-5-phosphonovaleric acid (D-AP-5) and mild hypothermia on neuronal MAP-2 following fluid percussion injury (FPI). METHODS: Alterations of MAP-2 in Wistar rat neurons following FPI were measured by a confocal laser-scanning microscope using MAP-2 immunofluorescence staining as a MAP-2 indicator. RESULTS: MAP-2 immunofluorescence staining was limited to the cell bodies and dendritic compartments of neurons and more intense in dendrites than in cell bodies. The loss of MAP-2 was marked at 3 h post-trauma (P < 0.01), and reached a maximum at 48 h post-trauma. Afterwards, fluorescence recovered partly at 72 h post-trauma. The application of Nim markedly reduced the loss of MAP-2 immunoreactivity within 1 h post-trauma (P < 0.01), and the application of D-AP-5 markedly reduced the loss of MAP-2 immunoreactivity within 10 h post-injury (P < 0.01). The application of mild hypothermia decreased the loss of MAP-2 immunoreactivity within 1 h post-injury (P < 0.05). CONCLUSIONS: The partial recovery of fluorescence at 72 h post-trauma indicate that the partial structure of the neuronal microtubules can be repaired by itself. Nim, D-AP-5 and mild hypothermia reduce the degradation of MAP-2 by different mechanisms. The treatment of neuronal cytoskeleton degradation following FPI must employ multiple therapeutic approaches.

2-Amino-5-phosphonovalerate↗
PubMed2001

[Diagnosis and management of endoleak after endovascular repair of abdominal aortic aneurysm].

OBJECTIVE: To determine the diagnosis and management of endoleak after endovascular repair of abdominal aortic aneurysm (AAA). METHODS: We analysed retrospectively the data of 37 cases of infrarenal AAA treated by endovascular repair and investigated the reasons, managements, results and prognosis of endoleaks. RESULTS: Of 13 patients with endoleak at stent-graft deployment, 6 developed type I endoleak, 3 type II endoleak, 2 type III endoleak, 1 type IV endoleak, and 1 unknown reason. Type I and III endoleaks disappeared after management with additional techniques. The primary endoleak rate was 13.5%(5/37). Three sealed endoleak, 2 persistent endoleaks and 2 secondary endoleaks were found during follow up. The late endoleak rate was 10.8% (4/37). CONCLUSIONS: Endoleak is a chief complication after endovascular repair of infrarenal AAA. The influencing factors for endoleak include neck morphology, distance, angulation, calcification, stent-graft selection and side branching arteries. Additional procedure and follow up are very important. Techniques to find endoleak include CTA, Duplex and MRA after operation. Endoleak with enlarged aneurysm should be treated actively.

Aortic Aneurysm, Abdominal↗
PubMed2001

[The coordinated expression of laminin and its integrin receptor in hepatic sinusoidal capillarization].

OBJECTIVE: To explore the expression of laminin and its integrin receptor alpha 6 in sinusoidal capillaration. METHODS: The rat hepatic fibrosis model was established by injection carbon tetrachloride subcutaneously. Liver sections were examined by scanning electron microscopy and special staining. Then expressions of laminin and integrin alpha 6 subunit were observed by immunohistochemistry and dot immuno-blotting. RESULTS: The pathologic character of hepatic fibrosis-sinusoidal capillaration was observed. Sinusoidal capillaration is characterized by defenestration of sinusoidal endothelial cells (SEC) and basement membrane forming and phenotype transformation. By immunohistochemistry staining. The deposition of laminin surrounding sinusoids according to fibrosis stage was 0, 1.92%, 6.02%, 9.68%, 14.14% respectively, statistically different from each other (P < 0.05). In normal rat no expression of integrin alpha 6 were observed in SEC membranes. When capillaration integrin alpha 6 was detected in a continuous pattern along the sinusoidal in accordance with laminin assembly. The content of integrin alpha 6 in fibrotic liver tissues were significantly higher than in normal liver tissues as measured by dot immuno-blotting (P < 0.05). CONCLUSIONS: During fibrogenesis laminin continuously accumulate in liver tissues and form basement membrane resulting in sinusoidal capillaration, meanwhile are company with induced expression of LN-binding-integrin alpha 6 on SEC membranes. These results suggest that coordinated expression of laminin and laminin-binding-integrin might be important in pathogenesis of sinusoidal capillaration and hepatic fibrosis.

Animals↗
PubMed2001

[Purification feasibility of malodorous waste gas contained H2S and CS2 by DBD technique].

Dielectric barrier discharge(DBD) technique was applied to remove H2S and CS2 in industrial waste gas. In the research of laboratory, when the voltage between two electrodes was 12 kV, 4 x 10(3) Pa H2S was discharged in air for 5 seconds, about 100% of H2S was transformed into H2O and SO2; 1.33 x 10(3) Pa CS2 was discharged in air for 15 seconds, about 80% of CS2 was transformed into CO2, CO and SO2. When the concentration of H2S and CS2 increased, the decomposition of them decreased. Based on the results, a DBD purification apparatus which can dispose 420 m3/h, 10 m/s waste gas was designed and manufactured, the removal rate of H2S can reach 89% and the energy consumption was 5.2 W.h/m3. It was concluded that the DBD technique is worth disposing malodorous industrial waste gases contained H2S and CS2.

Carbon Disulfide↗
PubMed2001

[The role of TGF-beta on Tca83--a tongue squamous cell carcinoma cell line].

OBJECTIVE: To investigate the role of TGF-beta on the growth of Tca83 cells. METHODS: The cell culture, MTT detection, immunohistochemistry and in situ hybridization detection methods were used. RESULTS: After 96 h, compared with the control, most groups with low concentrations of TGF-beta (0.2, 1.0, 5.0, 12.5 micrograms/L) showed growth inhibition, while the group with high concentration of TGF-beta (25.0 micrograms/L) showed no growth inhibition. Positive stain of TGF-beta 1, T beta R I mRNA and TGF-beta 1, T beta R I, T beta R II protein could be detected in Tca83 cells. CONCLUSIONS: Tca83 cell line has the potentiality to secret TGF-beta 1. Autocrine and paracrine of TGF-beta 1 could regulate cancer cell's proliferation and differentiation directly. Since the ligand-receptor conduction in Tca83 cell line is intact, external TGF-beta 1 could combine with the T beta R I and T beta R II receptor and exert its inhibitory effect on Tca83 cell line.

Activin Receptors, Type I↗
PubMed2001

[A case-control study on the risk factors of stomach cancer in Tianjin city].

OBJECTIVE: To explore the risk factors of stomach cancer in Tianjin. METHODS: A matched case-controls study was carried out. A total number of 189 patients with stomach cancer who were individually matched and interviewed. RESULTS: Multivariate conditional logistic analysis showed that stomach cancer was closely relate to the four factors: smoked food (OR = 2.34, 95% CI: 1.60-4.98), cigarettes smoking (OR = 6.07, 95% CI: 1.26-7.16), heavy salt intake (OR = 1.95, 95% CI: 1.27-3.23) and excessive intake of meats (OR = 1.46, 95% CI: 1.05-2.02) were risk factors for stomach cancer. CONCLUSION: Frequent eating smoked food, cigarettes smoking, heavy salt intake and over intake of meats were risk factors for stomach cancer.

Adult↗
PubMed2001

[Clinical characteristics and diagnosis of chronic intestinal pseudo-obstruction].

OBJECTIVE: To analyze and determine the clinical characteristics and diagnostic methods of chronic intestinal pseudo-obstruction(CIP). METHODS: We reviewed the medical records of all 23 patients who diagnosed with CIP in Peking Union Medical College Hospital from 1978 to 2000. RESULTS: Twenty three patients fulfilled the diagnostic criteria (9 male, 14 female, median age 50 years, range 4-75 years). The main symptoms at the presentation were abdominal distension(87%), pain(57%), diarrhea(65%), constipation(48%), vomiting(39%) and weight loss(83%). In this group of CIP patients, the abdominal distension was more common and serious than pain, presenting with diarrhea, weight loss and dismotility in esophagus and stomach. Bowel loops and visible peristaltic waves were seldom observed in the CIP patients. The plain film showed the multiple air-fluid levels (17/20, 85%) and generalized intestinal distention and air in colon. The abnormal findings on the barium contrast examination included intestinal dilation (19/23, 83%), weaken peristalses or/and prolongation of transit time (74%) without mechanical lesions. The pseudo-obstruction involved the small intestine (83%) and colon (39%) that determined according to the radiographic features, abnormal gastrointestinal motor functions, findings of endoscopic examination and laparotomy. Eighteen cases were chronic idiopathic intestinal pseudo-obstruction (1 familial myopathy), 5 were secondary to CTD. CONCLUSIONS: Comparison with the typical mechanical obstruction, the presentations of CIP have some relatively characteristics. The clinical diagnosis of CIP can be confirmed on the basis of typical clinical symptoms and radiographic features, abnormal gastrointestinal motility.

Adolescent↗
PubMed2001

[Use of microsatellites in zygosity diagnosis of twins].

OBJECTIVE: To diagnose zygosity of twins by microsatellite polymorphism. METHODS: One hundred and eighty-four samples, including 69 pairs of twins with the same gender and 6 pairs of twins with different gender were recruited. Seventeen sib pairs were also collected for controls. Nine highly polymorphic microsatellite loci were amplified by polymerase chain reaction (PCR) using fluorescence-labeled primers and the products were sized by automated fragment analysis after electrophoresis and laser detection. Zygosity was diagnosed by comparing the concordance of the genotype of the 9 markers. RESULTS: Sixty-three pairs of monozygotic (MZ) and 12 pairs of dizygotic (DZ) twins were assigned their zygosity by comparison of polymorphism of 9 microsatellite loci. Within each of the 63 monozygotic (MZ) pairs there was complete concordance. However, within each of the 12 dizygotic pairs and other 17 sib pairs, discordant loci were found. With five or six markers, the probability that any twin pair was MZ if all markers were concordant was 99% or 99.6%, respectively. With all the nine markers, the probability that any twin pair was MZ if all markers were concordant was 99.95%. CONCLUSION: The technology of gene scan and genotyping provides a rapid and reliable approach to zygosity detection.

DNA↗
PubMed2001

Activation of NF-kappa B in bronchial epithelial cells from children with asthma.

OBJECTIVES: To determine whether nuclear factor-kappa B (NF-kappa B) is activated in epithelial cells from children with asthma and to understand the role of NF-kappa B in airway inflammation in asthma. METHODS: Bronchial mucosa specimens were obtained from 9 children with asthma and 6 control subjects. NF-kappa B expression in epithelial cells were detected by immunohistochemical examination, and NF-kappa B-DNA binding was measured by electrophoretic mobility shift assay (EMSA). RESULTS: Nuclear expression of NF-kappa B in epithelial cells was observed in the 9 asthmatic children. NF-kappa B-DNA binding was found in 4 asthmatic children (EMSA was performed in 6 asthmatic children). In contrast, both nuclear expression and NF-kappa B-DNA binding were absent in the 6 control subjects. CONCLUSION: These results indicated that NF-kappa B is activated in epithelial cells from asthmatic children and the NF-kappa B activation may be the basis for the increased expression of many inflammatory genes and for airway inflammation in asthma.

Asthma↗
PubMed2001

Biological features of mesenchymal stem cells from human bone marrow.

OBJECTIVE: To study the biological characteristics of mesenchymal stem cells (MSCs) from human bone marrow. METHODS: A culture of mesenchymal stem cells was initiated from bone marrow low-density mononuclear cells separated by Percoll Centrifugation and maintained in low-glucose Dulbecco's modified Eagle's medium (DMEM) with 10% selected fetal calf serum. Cell growth pattern and its responses to cytokines were evaluated by trypan blue exclusion and MTT test, respectively. Cell cycle and surface antigenic features were analyzed by flow cytometry technique. Cytochemistry characteristics of MSCs were determined. RESULTS: Easy-handling methods to isolate and culture expand MSCs were developed in this study. MSCs were unique in their phenotypes. They were positive for CD29, CD44, CD166, and negative for CD34, CD45, HLA-DR and Ulex europaeus. Cytochemistry evaluation showed that MSCs were homogeneously positive for acid alpha-naphthl acetate esterase (ANAE), glycogen (periodic acid Schiff reaction, PAS), and negative for acid phosphatase (ACP) and the Sudan black reaction (SB). Around 5% of them were positive for alkaline phosphatase (ALP). The cells had a population doubling time of 30 hours and cell cycle analysis showed that approximately 10% of them were in S phase. MSCs grew at significantly different rates when incubated in the presence of various recombinant human cytokines, of which interferon gamma, tumor necrosis factor alpha, stem cell factor and insulin-like growth factor promoted the proliferation of MSCs dramatically, while others tested had no effects on cell growth. CONCLUSIONS: MSCs are a homogenous population of cells that have unique growth, phenotypical and cytochemical characteristics. Furthermore, the diverse responses of MSCs to different cytokines provide a clue for the selection of optimal expansion and maintenance of MSCs.

Activated-Leukocyte Cell Adhesion Molecule↗
PubMed2001

Molecular basis for the effect of lipid lowering drugs on growth factors after de-endothelialization.

OBJECTIVE: To study the mechanism and effect of lipid lowering drugs in arresting the development of arterial restenosis after angioplasty. METHODS: De-endothelialization injury of rabbit aortae, common iliac and femoral arteries using balloon angioplasty and the expression of growth factors such as platelet derived growth factor-B (PDGF-B), transforming growth factor beta-1 (TGF beta-1), and fibroblast growth factors (bFGF) were investigated. Total serum cholesterol (TC) and triglycerides (TG) were analyzed during and after the treatment using either simvastatin combined with gemfibrozil or simvastatin alone for 6 weeks. RESULTS: Serum total cholesterol and triglycerides were only slightly to moderately increased after high cholesterol ration intake lasting for 6 weeks in rabbits of two therapeutic groups (simvastatin plus gemfibrozil or only simvastatin). A positive correlation was found between TC and intimal/medial ratio (r = 0.5873, P < 0.05). PDGF-B detected by immuno-histochemistry and RT-PCR analysis showed that the release of PDGF-B was inhibited by simvastatin and gemfibrozil after de-endothelialization. RT-PCR analysis showed that TGF beta-1 was increased in the neointima in two treatment groups but no definite change was seen in the mRNA of bFGF in the smooth muscle cell (SMC) of the balloon-injured arteries even under lipid lowering drug treatment. CONCLUSION: In addition to the lipid lowering effect, both simvastatin and gemfibrozil also influence the release of PDGF-Band TGF-1 in the neointima after de-endothelialization.

Animals↗
PubMed2001

Optical coherence tomography in measuring retinal nerve fiber layer thickness in normal subjects and patients with open-angle glaucoma.

OBJECTIVES: To investigate image characteristics and thickness of the retinal nerve fiber layer (RNFL) in normal and glaucomatous eyes using optical coherence tomography (OCT), and analyze the relationship between RNFL thickness and visual field index. METHODS: Eighty-three normal persons (150 eyes) and 83 patients with primary open angle glaucoma (POAG, 149 eyes) underwent OCT examinations with 3.4 mm diameter circle scan to calculate the RNFL thickness. Statistical analysis was used to compare differences in RNFL thickness in quadrants and means between the normal and glaucomatous groups and the different stages of POAG. Linear correlation and regression analysis were used to show the correlation between RNFL thickness and visual field index of 115 eyes in glaucomatous patients. Reproducibility, sensitivity and specificity of RNFL measurements using OCT were evaluated. RESULTS: RNFL thickness measured by OCT in normal subjects was thicker in superior and inferior, less in temporal, and thinnest in nasal quadrants. The curve showed double peaks. RNFL of glaucomatous patients showed local thinning or defect, diffuse thinning, or both. The mean RNFL thicknesses of the normal group in the temporal, superior, nasal and infelor quadrants were 90.1 +/- 10.8 microns, 140.4 +/- 10.5 microns, 85.2 +/- 14.0 microns, and 140.4 +/- 9.7 microns, respectively with a mean of 114.2 +/- 6.0 microns. The numbers for the glaucomatous group were respectively 56.0 +/- 31.0 microns, 81.0 +/- 36.3 microns, 47.1 +/- 27.5 microns, and 73.4 +/- 38.4 microns for the four quadrants, with a mean of 64.6 +/- 28.8 microns. There was a significant difference in RNFL thickness between the normal and glaucomatous groups (P < 0.000), and the three stages (early, developing and late) of glaucomatous groups (P < 0.000). There was a close negative relationship between RNFL thickness and visual field index (r = -0.796, P < 0.0001). The sensitivity and specificity of RNFL thickness in POAG measured using OCT were 93.3% and 92.0%, respectively. CONCLUSIONS: OCT can quantitatively measure RNFL thickness differences between normal persons and glaucomatous patients. RNFL thickness gradually decreases while visual field defect increases with the development of POAG.

Adolescent↗
PubMed2001

Simian virus 40 large tumor antigen forms specific complexes with p53 and pRb in human brain tumors.

OBJECTIVE: To study the role of simian virus 40 (SV40) early region gene coding product large tumor antigen (Tag) expression and the interaction between Tag and tumor suppressors p53 and pRb in human brain tumorigenesis. METHODS: Tag was investigated by immunoprecipitation followed by silver staining and Western blot in 65 cases of human brain tumors and 8 cases of normal brain tissues. Tag-p53 and Tag-pRb complexes were screened in 18 and 15 Tag positive tumor tissues, respectively. RESULTS: Tag was found in all 8 ependymomas and 2 choroid plexus papillomas, 90% of pituitary adenomas (9/10), 73% of astrocytomas (11/15), 70% of meningiomas (7/10), 50% of glioblastomas multiforme (4/8), 33% of medulloblastomas (2/6). 5 oligodendrogliomas, 1 pineocytoma, and 8 normal brain tissues were negative for Tag. Tag-p53 complex was detected in all 18 Tag positive tumors. Tag-pRb complex was found in all 15 Tag positive tumors. CONCLUSION: SV40 Tag is expressed in human brain tumors and can form specific complexes with tumor suppressors p53 and pRb. The inactivation of p53 and pRb due to the formation of Tag-p53 and Tag-pRb complexes may be an important mechanism in the etiopathogenesis of human brain tumors.

Animals↗
PubMed2001

[Changes of the expression of integrin alpha6beta1 and the activity of focal adhesion kinase in the liver sinusoidal endothelial cell in experimental fibrotic rats].

OBJECTIVE: To investigate the expression of integrin alpha(6)beta(1) and the activity of focal adhesion kinase (FAK) in liver sinusoidal endothelial cells (SECs) from experimental fibrotic rats induced by CCl(4). METHODS: By in situ collagenase perfusion and two-step Percoll gradient centrifugation, SECs were isolated and cultured from normal and CCl(4) -treated Wistar rats. The expression of integrin alpha(6)beta(1) was determined by cell-ELISA, and the activity of FAK was assessed by immunoprecipitation-tyrosine kinase assay. RESULTS: The integrin alpha(6)beta(1) was almost absent in the normal SECs and was up-regulated during the fibrotic process; SECs from experimental fibrotic rats possessed higher expression level of integrin alpha(6)beta(1) than normal SECs (P<0.05). The FAK activity in SECs from experimental fibrotic rats increased significantly as compared with the normal controls (P<0.05). CONCLUSIONS: The expression of integrin alpha(6)beta(1) on SECs and the increase of FAK in SECs may be important in the phenotype and function changes of SECs during hepatic fibrogenesis.

Animals↗
PubMed2001

[Cloning of drug resistance-related gene fragments differentially expressed on lung adenocarcinoma cell line A549 and its DDP-resistant counterpart A549DDP].

OBJECTIVE: To clone drug resistance-related genes of lung adenocarcinoma. METHOD: The difference in gene expression between A549 and A549DDP was identified by mRNA differential display technique. Genes differentially expressed were cloned and confirmed by Northern blot. RESULTS: Four cDNA fragments of differentially expressed genes were obtained and sequenced. Of the 4 cDNA fragments, 2 (A1 and D1) did not show sequence homology with the existing genes in the GeneBank, one (A2) was 89% homologous with interleukin 1 beta converting enzyme (ICE) gene, and the other (D2) was identical to mouse musculus 45s pre-rRNA (MM45srRNA) gene. Both cDNA fragments A1 and A2 were expressed in A549 but not or barely expressed in A549DDP, while fragments D1 and D2 were expressed in A549DDP but not in A549. CONCLUSION: Four differentially expressed gene fragments between lung adenocarcinoma cell line and its cisplatin-resistant counterpart were identified by mRNA differential display technique. It remains to be studied whether the newly identified gene fragments and those showing sequence homology to ICE and MM45srRNA are indeed positively or negatively related to drug resistance.

Adenocarcinoma↗