Biomedical subjects

Qing Liu

Publications and source records attributed to Qing Liu.

At least 127 records · Page 7Linked to original sources

PubMed2003

[Quantitative study on tongue color in primary liver cancer patients by analysis system for comprehensive information of tongue diagnosis].

OBJECTIVE: To explore the characteristics of tongue color in patients with primary liver cancer (PLC). METHODS: Tongue color and its RGB value were analyzed quantitatively for PLC patients in different clinical periods and other cancer patients by analysis system for comprehensive information of tongue diagnosis. RESULTS: The rate of blue and purple tongue was higher (P<0.05) and all the values of RGB were lower (P<0.01) in PLC patients compared with other cancer patients. In different clinical periods, the rate of blue and purple tongue in stage III was the highest (P<0.05). CONCLUSION: The blue and purple tongue is one of the most important tongue characteristics of PLC patients.

Adult↗

PubMed2003

[Detection of eosinophil cationic protein and E-selectin in serum and nasal lavage fluid in patients with allergic rhinitis].

OBJECTIVE: To evaluate the role of eosinophil cationic protein (ECP) and serum soluble E-selectin (sE-selectin) in patients with allergic rhinitis. METHODS: The sE-selectin were detected from 30 allergic patients and 20 normal individuals by enzyme-linked immunosorbent assay (ELISA). The ECP in serum and nasal lavage fluid was assayed with pharmacia CAP system. RESULTS: The level of sE-selectin in patients with allergic rhinitis was(41.846 +/- 12.21) ng/ml, higher than that in control (10.678 +/- 2.458) ng/ml. The level of ECP in serum and nasal lavage fluid from patients with allergic rhinitis was significantly higher than that from normal controls. The level of ECP in nasal lavage fluid was much higher than that in serum. CONCLUSION: ECP and sE-selectin play a role in pathogenesis of allergic rhinitis.

Adolescent↗

PubMed2003

[Investigation on the gene expression pattern in cervical squamous cell carcinoma of uygur].

OBJECTIVE: To investigate the differentially expressed gene in cervical squamous cell carcinoma of uygur and normal cervical tissue using gene chip. METHOD: Gene chips containing 2,048 human genes were used to investigate the gene expression pattern of 3 samples of cervical cancer. RESULT: By applying this gene chip we identified 64 differentially expressed genes in all 3 clinical cervical cancer samples, and we further identified 53 upregulated and 11 downregulated genes for functional analysis. CONCLUSION: The analysis of gene expression pattern of tumor based on gene chip can realize high-throughput screening of the genes associated with the cervical cancer.

Carcinoma, Squamous Cell↗

PubMed2003

[Infrared spectroscopic investigation on complexes formed from cupric fluoborate and cupric butyrate with Bis (diphenylphosphino) alkane ligands].

The Bis (diphenylphosphino) alkane series ligands and its series of complexes formed from Cu(BF4)2 and Cu(C3H7COO)2 respectively were studied by infrared spectral analysis. This paper discusses the spectral classification and the change regularity of related spectra before and after the Cu(I) complexes were formed. The possible structure model of the formed complexes was discussed, based on the element analysis, powder X-ray diffraction analysis, and thermal gravity analysis.

Borates↗

PubMed2003

[Forest gap characteristic in a coniferous-Picea likiangensis forest in the Yulong Snow Mountain Natural Reserve, Yunnan Province, China].

In this paper, some important parameters related to the gap disturbance regimes in a coniferous-Picea likiangensis forest in the Yulong Snow Mountain Natural Reserve, Yunnan Province were described. The results showed that expanded gaps occupied 42.5%, and canopy gaps occupied 28.8% of the land area in the forest. The frequency of gap disturbance was 35 gaps per hectares. There were 25% of small (gap area < 50 m2), 41% of middle (gap area 50-100 m2), and 34% of large (gap area > 100 m2) forest gaps. The most important manner of gap formation was the breakage at trunk base and its middle, and the secondly important manner was rotten. Gap maker in the forest was more than 80% of Picea likiangensis. The probability of making gaps was the greatest, when the big trees in the canopy layer got DBH 40-50 cm and height 15-25 m. Gaps formed by 1-2 gap makers was of 68.8%, and by 5 gap makers was seldom. The most of gap makers were 6 in a gap of the forest. The density of the seedlings in gap gradually increased with the forest gap from large to small.

Conservation of Natural Resources↗

PubMed2003

[Studies of poly(vinyl alcohol)/hydroxylapatite hydrogels compounds for cartilage implantation].

The structures and properties of polyvinyl alcohol (PVA)/hydroxylapatite(HA) composites were investigated. The components and processing conditions were studied for preparation of optimum compound hydrogels with good lubricating feature and high bioactivity. The properties, such as stretch strength, compress strength, friction, compress stress relaxation of various compound hydrogels were compared. The micro-morphology of PVA hydrogels and PVA/HA hydrogels were investigated by use of SEM. It was found that the addition of HA could improve the lubricating feature and mechanical strength of hydrogels, and its compress stress relaxation properties were closer to those of natural cartilages.

Biocompatible Materials↗

PubMed2003

[Review of poly(vinyl alcohol) hydrogel and its compounds in the application of artificial cartilage materials].

Poly(vinyl alcohol) (PVA) hydrogel is a kind of material which has excellent biocompatibility and mechanical properties. In this paper, the researches and developments of PVA hydrogel preparation and the modifications of PVA with other material were introduced. The potential for the use of PVA hydrogels as implant materials in cartilage reparation was reviewed.

Biocompatible Materials↗

PubMed2002

Polarization optimization in the interference of four umbrellalike symmetric beams for making three-dimensional periodic microstructures.

A systematic and comprehensive analysis of the interference of four umbrellalike beams (lFUB) is provided based on the reciprocal space theory. The concept of pattern contrast is extended to the case of the IFUB, and it is indicated that a uniform contrast for all the interference terms can be obtained by properly choosing the beam ratio and the polarization of each beam. Different polarization combinations, including linear light and linear light, circular light and circular light, and linear light and circular light, have been discussed for the purpose of maximum uniform contrast. It is shown that the use of circular light may generally improve the uniform contrast. This study may lay a theoretical foundation for holographic fabrication of three-dimensional (3D) periodic microstructures, such as simple cubic, body-centered cubic, face-centered cubic, or trigonal lattice.

Journal Article↗

PubMed2002

The cathepsin B of Toxoplasma gondii, toxopain-1, is critical for parasite invasion and rhoptry protein processing.

Cysteine proteinases play a major role in invasion and intracellular survival of a number of pathogenic parasites. We cloned a single copy gene, tgcp1, from Toxoplasma gondii and refolded recombinant enzyme to yield active proteinase. Substrate specificity of the enzyme and homology modeling identified the proteinase as a cathepsin B. Specific cysteine proteinase inhibitors interrupted invasion by tachyzoites. The T. gondii cathepsin B localized to rhoptries, secretory organelles required for parasite invasion into cells. Processing of the pro-rhoptry protein 2 to mature rhoptry proteins was delayed by incubation of extracellular parasites with a cathepsin B inhibitor prior to pulse-chase immunoprecipitation. Delivery of cathepsin B to mature rhoptries was impaired in organisms with disruptions in rhoptry formation by expression of a dominant negative micro1-adaptin. Similar disruption of rhoptry formation was observed when infected fibroblasts were treated with a specific inhibitor of cathepsin B, generating small and poorly developed rhoptries. This first evidence for localization of a cysteine proteinase to the unusual rhoptry secretory organelle of an apicomplexan parasite suggests that the rhoptries may be a prototype of a lysosome-related organelle and provides a critical link between cysteine proteinases and parasite invasion for this class of organism.

Amino Acid Sequence↗

PubMed2002

Activation and inactivation of neuronal nitric oxide synthase: characterization of Ca(2+)-dependent [125I]Calmodulin binding.

Constitutive isoforms of nitric oxide synthase (NOS) are activated by transient binding of Ca(2+)/Calmodulin. Here, we characterize the binding of Calmodulin to purified neuronal NOS (nNOS). [125I]Calmodulin bound to a single class of non-interacting and high affinity sites on nNOS. [125I]Calmodulin binding achieved rapid saturation, was linear with nNOS concentration, and exhibited a strict dependence on [Ca(2+)]. Neither affinity nor extent of [125I]Calmodulin binding was affected by L-arginine, NADPH or Tetrahydrobiopterin. Native Calmodulin and engineered Calmodulin homologs [i.e., duplicated N-terminal (CaMNN)] potently displaced [125I]Calmodulin. CaMNN supported nNOS catalysis, but required approximately five-fold more Ca(2+) for comparable activity with native Calmodulin. Taken with results from kinetic analyses of [125I]Calmodulin association and dissociation, our findings suggest four sequential steps in activation of nNOS by Calmodulin: (1) Ca(2+) binds to Calmodulin's C-lobe, (2) the C-lobe of Calmodulin binds NOS, (3) Ca(2+) binds to the N-lobe of Calmodulin, and (4) the N-lobe binds to nNOS. Activation of nNOS only occurs after completion of step (4), with the displacement of nNOS's autoinhibitory insert. Upon intracellular Ca(2+) sequestration, deactivation of nNOS would proceed in reverse order.

Animals↗

PubMed2002

FLT3 internal tandem duplication mutations associated with human acute myeloid leukemias induce myeloproliferative disease in a murine bone marrow transplant model.

FLT3 receptor tyrosine kinase is expressed on lymphoid and myeloid progenitors in the hematopoietic system. Activating mutations in FLT3 have been identified in approximately 30% of patients with acute myelogenous leukemia, making it one of the most common mutations observed in this disease. Frequently, the mutation is an in-frame internal tandem duplication (ITD) in the juxtamembrane region that results in constitutive activation of FLT3, and confers interleukin-3 (IL-3)-independent growth to Ba/F3 and 32D cells. FLT3-ITD mutants were cloned from primary human leukemia samples and assayed for transformation of primary hematopoietic cells using a murine bone marrow transplantation assay. FLT3-ITDs induced an oligoclonal myeloproliferative disorder in mice, characterized by splenomegaly and leukocytosis. The myeloproliferative phenotype, which was associated with extramedullary hematopoiesis in the spleen and liver, was confirmed by histopathologic and flow cytometric analysis. The disease latency of 40 to 60 days with FLT3-ITDs contrasted with wild-type FLT3 and enhanced green fluorescent protein (EGFP) controls, which did not develop hematologic disease (> 200 days). These results demonstrate that FLT3-ITD mutant proteins are sufficient to induce a myeloproliferative disorder, but are insufficient to recapitulate the AML phenotype observed in humans. Additional mutations that impair hematopoietic differentiation may be required for the development of FLT3-ITD-associated acute myeloid leukemias. This model system should be useful to assess the contribution of additional cooperating mutations and to evaluate specific FLT3 inhibitors in vivo.

Amino Acid Sequence↗

PubMed2002

The role of surface functional groups in calcium phosphate nucleation on titanium foil: a self-assembled monolayer technique.

Surface functional groups play important roles in nucleating calcium phosphate deposition on surgical titanium implants. In this study, various functional groups were introduced onto the surface of commercially pure titanium foils using a self-assembled monolayer (SAM) technique. An organic silane, 7-oct-1-enyltrichlorosilane (OETS) was used and -OH, -PO4H2, -COOH groups were derived from its unsaturated double bond. Ti foils were first oxidized in concentrated H2SO4/H2O2. ESCA and contact angle measurements were used to characterize the SAM surfaces and confirm the presence of various functional groups. A fast calcium phosphate deposition experiment was carried out by mixing Ca2+- and (PO4)(3-)-containing solutions in the presence of the surface-modified Ti samples at pH 7.4 at room temperature in order to verify the nucleating abilities of these functional groups. SEM, Raman spectroscopy, XRD and ATR-FTIR results showed that poorly crystallized hydroxyapatite (HA) can be deposited on the SAM surfaces with -PO4H2 and -COOH functional groups, but not onto the SAM with -CH=CH2 and -OH. -PO4H2 exhibited a stronger nucleating ability than that of -COOH. The oxidized Ti sample also showed some calcium phosphate deposition but to a lesser extent as compared to SAM surfaces with -PO4H2 and -COOH. The pre-deposited HA can rapidly induce biomimetic apatite layer formation after immersion in 1.5 SBF for 18 h regardless of the amount of pre-deposited HA. The results suggested that the pre-deposition of HA onto these functionalized SAM surfaces might be an effective and fast way to prepare biomimetic apatite coatings on surgical implants.

Biocompatible Materials↗

PubMed2002

High-oleic and high-stearic cottonseed oils: nutritionally improved cooking oils developed using gene silencing.

Gene technology and plant breeding are combining to provide powerful means for modifying the composition of oilseeds to improve their nutritional value and provide the functional properties required for various food oil applications. Major alterations in the proportions of individual fatty acids have been achieved in a range of oilseeds using conventional selection, induced mutation and, more recently, post-transcriptional gene silencing (PTGS). In particular, a number of high-oleic oils have been developed in order to provide high-stability cooking oils. These oils provide the opportunity to replace the current widespread use of saturated fats and hydrogenated oils that contribute significantly to increased risk of cardiovascular disease due to the effect of saturated and trans-fatty acids on elevating LDL cholesterol in the bloodstream. Similarly, oils with increased stearic acid content are being developed to enable the production of solid fats without the need for hydrogenation. We have recently applied hpRNA-mediated PTGS in cotton to down-regulate key fatty acid desaturase genes and develop nutritionally-improved high-oleic (HO) and high-stearic (HS) cottonseed oils (CSOs). Silencing of the ghFAD2-1 delta12-desaturase gene raised oleic acid content from 13% to 78% and silencing of the ghSAD-1 delta9-desaturase gene substantially increased stearic acid from the normal level of 2% to as high as 40%. Additionally, palmitic acid was significantly lowered from 26% to 15% in both HO and HS lines. Intercrossing the HS and HO lines resulted in a wide range of unique intermediate combinations of palmitic, stearic, oleic and linoleic contents. The oxidative stability, flavor characteristics and physical properties of these novel CSOs are currently being evaluated by food technologists.

Cottonseed Oil↗

PubMed2002

High-stearic and High-oleic cottonseed oils produced by hairpin RNA-mediated post-transcriptional gene silencing.

We have genetically modified the fatty acid composition of cottonseed oil using the recently developed technique of hairpin RNA-mediated gene silencing to down-regulate the seed expression of two key fatty acid desaturase genes, ghSAD-1-encoding stearoyl-acyl-carrier protein Delta 9-desaturase and ghFAD2-1-encoding oleoyl-phosphatidylcholine omega 6-desaturase. Hairpin RNA-encoding gene constructs (HP) targeted against either ghSAD-1 or ghFAD2-1 were transformed into cotton (Gossypium hirsutum cv Coker 315). The resulting down-regulation of the ghSAD-1 gene substantially increased stearic acid from the normal levels of 2% to 3% up to as high as 40%, and silencing of the ghFAD2-1 gene resulted in greatly elevated oleic acid content, up to 77% compared with about 15% in seeds of untransformed plants. In addition, palmitic acid was significantly lowered in both high-stearic and high-oleic lines. Similar fatty acid composition phenotypes were also achieved by transformation with conventional antisense constructs targeted against the same genes, but at much lower frequencies than were achieved with the HP constructs. By intercrossing the high-stearic and high-oleic genotypes, it was possible to simultaneously down-regulate both ghSAD-1 and ghFAD2-1 to the same degree as observed in the individually silenced parental lines, demonstrating for the first time, to our knowledge, that duplex RNA-induced posttranslational gene silencing in independent genes can be stacked without any diminution in the degree of silencing. The silencing of ghSAD-1 and/or ghFAD2-1 to various degrees enables the development of cottonseed oils having novel combinations of palmitic, stearic, oleic, and linoleic contents that can be used in margarines and deep frying without hydrogenation and also potentially in high-value confectionery applications.

Crosses, Genetic↗

PubMed2002

hpRNA-mediated targeting of the Arabidopsis FAD2 gene gives highly efficient and stable silencing.

The endogenous Delta 12-desaturase gene (FAD2) in Arabidopsis was targeted for silencing using seed-specific cosuppression (CS), hairpin (HP) RNA (hpRNA), and intron-spliced HP (iHP) constructs. The iHP construct, incorporating the 120-bp 3'-untranslated region of the FAD2 gene, gave the highest degree of silencing. In some iHP lines Delta 12-desaturase activity was reduced to levels as low as those in the null fad2-1 mutant, and every primary transformant showed a pronounced reduction in FAD2 activity. One highly silenced iHP line was propagated for five generations and showed no reversion or diminution in its degree of silencing. About 75% of plants transformed with the HP construct, targeting the FAD2 coding region, gave dramatically reduced Delta 12-desaturase activity, whereas approximately 50% of plants transformed with the CS construct, containing the same coding region sequence, showed silencing at a much less profound level. In all three types of constructs, the degree of silencing was increased when the transgenes were homozygous, but this was much more pronounced for the CS constructs. All three types of construct could give a single locus that was capable of effective silencing, but in the one such CS line where this was the case, the locus had a complex insertion pattern. This is consistent with the concept that posttranscriptional gene silencing is induced by double-stranded, or self-complementary, RNA that is formed in cases of CS by complex insertion patterns at a single locus and that the most effective way of generating profoundly silenced plants is by the use of constructs that encode hpRNAs. Furthermore, these results demonstrate for the first time, to our knowledge, that iHP constructs targeted against an endogenous seed-expressed gene are clearly able to generate phenotypic changes that are inherited stably over several generations, making this approach a reliable technique for genetic modification of seed quality and possibly other traits in agricultural plants.

Arabidopsis↗

PubMed2002

Effects of hexamethylene diisocyanate exposure on human airway epithelial cells: in vitro cellular and molecular studies.

In this study we developed an in vitro exposure model to investigate the effects of hexamethylene diisocyanate (HDI) on human airway epithelial cells at the cellular and molecular level. We used immunofluorescence analysis (IFA) to visualize the binding and uptake of HDI by airway epithelial cell lines (A549 and NCI-NCI-H292) and microarray technology to identify HDI sensitive genes. By IFA, we observed that subcytotoxic concentrations of HDI form microscopic micelles that appear to be taken up by cells over a 3-hr period postexposure. Microarray analysis (4.6K genes) of parallel cultures identified four genes (thioredoxin reductase, dihydrodiol dehydrogenase, TG interacting factor, and stanniocalcin) whose mRNA levels were up-regulated after HDI exposure. Northern analysis was used to confirm that HDI increased message levels of these four genes and to further explore the dose dependence and kinetics of the response. The finding that HDI exposure increases thioredoxin reductase expression supports previous studies suggesting that HDI alters thiol-redox homeostasis, an important sensor of cellular stress. Another of the HDI-increased genes, a dihydrodiol dehydrogenase, encodes a protein previously shown to be specifically susceptible to HDI conjugation, and known to detoxify other hydrocarbons. Together, the data describe a novel approach for investigating the effects of HDI binding and uptake by human airway epithelial cells and begin to identify genes that may be involved in the acute response to exposure.

Air Pollutants↗

PubMed2002

[Transposition of pedicled sternocleidomastoid muscle for repair of facial paralysis in late stage].

OBJECTIVE: To explore a new surgical approach to repair facial paralysis in late stage, using regional transposition of pedicled sternocleidomastoid muscle for the dynamic reanimation of the paralyzed face. METHODS: Seven cases with facial paralysis in late stage from December 1999 were treated and followed up for 10 months before clinical evaluation. In all of the cases, the sternal and clavicular branches of the sternocleidomastoid muscle were both elevated from their bony attachments, with the mastoid insertion left in situ as the pedicle for blood supply and accessory nerve maintained in it. The muscle strips were transposed and sutured to the orbicularis oris around the mouth corner on the paralyzed side. RESULTS: Static asymmetry of nose and oral commissure on the paralyzed side were corrected immediately after operation, and the movement of the oral commissure recovered one week after operation. Symmetric smiling was observed in one month and all of the oral movements recovered in 10 months postoperatively. CONCLUSION: The new approach to repair facial paralysis in late stage by regional transposition of pedicled sternocleidomastoid muscle is effective in restoration of both static and dynamic symmetry of nose and mouth, and in recovery of the facial expression and the oral commissure.

Adult↗

PubMed2002

[Study on genetic epidemiology of nasopharyngeal carcinoma in Guangdong, China].

OBJECTIVE: To explore the characteristic of genetic epidemiology of nasopharyngeal carcinoma (NPC) in a high risk area Guangdong province, China. METHODS: Population investigation was made on the nuclear pedigrees of the first patient with NPC and his/her spouse, and then complex segregation analysis was performed using regressive Logistic model. RESULTS: The risk of suffering from NPC is 9.31 times higher in the first degree relatives of patient with NPC than in the first degree relatives of spouse. The separation ratio and heritability are 0.0588 (0.0182, 0.0994) and 68.08% respectively. The result of complex segregation analysis shows that model D is better than model A. CONCLUSION: The genetic trend and familial clustering of NPC are more significant and powerful in Guangdong. The risk of suffering from NPC is related with parent's state and senior sibling's state. Nasopharyngeal carcinoma is a multi-gene hereditary disease, but a single gene that decides the susceptibility to NPC may be present.

Adult↗