Biomedical subjects

Ping Chen

Publications and source records attributed to Ping Chen.

193 records · Page 11Linked to original sources

PubMed2002

The oxygen radical scavenger pyrrolidine dithiocarbamate enhances interleukin-1beta-induced cyclooxygenase-2 expression in cerebral microvascular smooth muscle cells.

Oxidative stress and inducible cyclooxygenase-2 (COX-2)-mediated prostaglandin (PG) formation have been proposed to play an important role in cytokine-induced vascular pathology. To explore the relationship between oxidative stress and COX-2 induction, cultured murine cerebral microvascular smooth muscle cells (SMCs) were stimulated with interleukin-1beta (IL-1beta) in the presence or absence of an oxygen radical scavenger, pyrrolidine dithiocarbamate (PDTC). IL-1beta increased COX-2 protein expression in a dose- and time-dependent manner, an increase that was further enhanced by PDTC in a dose-dependent manner. PDTC did not, however, affect the expression of COX-1 protein. In the presence of 100 microM PDTC, PGE(2) production induced by IL-1beta (5 ng/ml) was increased by threefold as compared with IL-1beta alone. Although PDTC enhanced COX-2 protein expression, it did not increase IL-1beta-induced expression of COX-2 mRNA, indicating that the regulatory effect occurred at the posttranscriptional level. The time course of COX-2 protein degradation indicated that PDTC also did not alter the stability of the COX-2 protein induced by IL-1beta. These results suggest that endogenous oxygen radicals may blunt COX-2 induced by IL-1beta through an effect on translation.

Animals↗

PubMed2002

Expression patterns of aquaporins in the inner ear: evidence for concerted actions of multiple types of aquaporins to facilitate water transport in the cochlea.

Water transport between the perilymph and endolymph is important in regulations of volume and osmotic pressure of the inner ear labyrinth. It is now known that expression of water channels (aquaporins or AQPs) in the cell membrane dramatically increases the ability of water to cross epithelial cells. The aims of the current study were to investigate the cellular localization of AQPs by immunolabeling, and to study the developmental expression and relative abundance of various subtypes of AQPs. We report here that AQP3, AQP7 and AQP9 were expressed in the inner ear. Specific subtypes of AQPs were found in discrete regions expressed by both epithelial cells and fibrocytes in cochlear and vestibular organs. Semi-quantitative measurements showed that AQP4 and AQP1 were the two most abundantly expressed AQP subtypes in the inner ear, and their expressions were dramatically upregulated during development. These data showed a highly localized and largely non-overlapping distribution pattern for different subtypes of AQPs in the inner ear, suggesting the existence of regional subtype-specific water transport pathways, and global regulation of water transport in the inner ear may require concerted actions of multiple types of AQPs.

Aging↗

PubMed2002

Calcium transients in the garter snake vomeronasal organ.

The signaling cascade involved in chemosensory transduction in the VN organ is incompletely understood. In snakes, the response to nonvolatile prey chemicals is mediated by the vomeronasal (VN) system. Using optical techniques and fluorescent Ca(2+) indicators, we found that prey-derived chemoattractants produce initially a transient cytosolic accumulation of [Ca(2+)](i) in the dendritic regions of VN neurons via two pathways: Ca(2+) release from IP(3)-sensitive intracellular stores and, to a lesser extent, Ca(2+) influx through the plasma membrane. Both components seem to be dependent on IP(3) production. Chemoattractants evoke a short-latency Ca(2+) elevation even in the absence of extracellular Ca(2+), suggesting that in snake VN neurons, Ca(2+) release from intracellular stores is independent of a preceding Ca(2+) influx, and both components are activated in parallel during early stages of chemosensory transduction. Once the response develops in apical dendritic segments, other mechanisms can also contribute to the amplification and modulation of these chemoattractant-mediated cytosolic Ca(2+) transients. In regions close to the cell bodies of the VN neurons, the activation of voltage-sensitive Ca(2+) channels and a Ca(2+)-induced Ca(2+) release from intracellular ryanodine-sensitive stores secondarily boost initial cytosolic Ca(2+) elevations increasing their magnitude and durations. Return of intracellular Ca(2+) to prestimulation levels appears to involve a Ca(2+) extrusion mediated by a Na(+)/Ca(2+) exchanger mechanism that probably plays an important role in limiting the magnitude and duration of the stimulation-induced Ca(2+) transients.

Animals↗

PubMed2002

The role of Math1 in inner ear development: Uncoupling the establishment of the sensory primordium from hair cell fate determination.

During embryonic development of the inner ear, the sensory primordium that gives rise to the organ of Corti from within the cochlear epithelium is patterned into a stereotyped array of inner and outer sensory hair cells separated from each other by non-sensory supporting cells. Math1, a close homolog of the Drosophila proneural gene atonal, has been found to be both necessary and sufficient for the production of hair cells in the mouse inner ear. Our results indicate that Math1 is not required to establish the postmitotic sensory primordium from which the cells of the organ of Corti arise, but instead is limited to a role in the selection and/or differentiation of sensory hair cells from within the established primordium. This is based on the observation that Math1 is only expressed after the appearance of a zone of non-proliferating cells that delineates the sensory primordium within the cochlear anlage. The expression of Math1 is limited to a subpopulation of cells within the sensory primordium that appear to differentiate exclusively into hair cells as the sensory epithelium matures and elongates through a process that probably involves radial intercalation of cells. Furthermore, mutation of Math1 does not affect the establishment of this postmitotic sensory primordium, even though the subsequent generation of hair cells is blocked in these mutants. Finally, in Math1 mutant embryos, a subpopulation of the cells within the sensory epithelium undergo apoptosis in a temporal gradient similar to the basal-to-apical gradient of hair cell differentiation that occurs in the cochlea of wild-type animals.

Animals↗

PubMed2002

[Eotaxin in induced sputum in patients with asthma and chronic bronchitis: relationship with airway inflammation].

OBJECTIVE: Investigate the roles of eotaxin (chemotactic factor of eosinophils) in pathogenesis of eosinophilic airway inflammation and airflow obstruction. METHODS: 33 patients in exacerbations with chronic bronchitis (CB group), chronic asthmatic bronchitis (CAB group) and bronchial asthma (BA group) (11 cases respectively) and 7 healthy volunteers as controls (C group) have participated in lung function test and sputum induction. The concentration of eotaxin in supernatant was measured by sandwich enzyme linked immunosorbent assay (ELISA). RESULTS: The differences of the eosinophil (EOS)/leukocyte (Leu)% in CAB group [(23.4 +/- 5.8)%], BA group [(20.7 +/- 3.1)%] and in CB group [(11.6 +/- 2.6)%], C group [(1.2 +/- 0.3)%] are significant (P < 0.001), and the differences of the level of eotaxin in CAB group [(0.290 +/- 0.170) g/L], BA group [(0.240 +/- 0.140) g/L] and in CB group [(0.120 +/- 0.020) g/L], C group [(0.030 +/- 0.050) g/L] are also significant [CAB group-CB group (P = 0.007); CAB group-C group (P < 0.001); BA group-CB group (P = 0.018); BA group-C group (P = 0.001)], but the differences of those in BA group and in CAB group are not significant (P = 0.196, 0.490). The EOS/Leu % is significantly inversely correlated with the percentage of the first second forced expiratory volume/predicted value (FEV(1)%) in CAB group (r = -0.921, P < 0.001). The EOS/Leu % and the level of eotaxin are significantly inversely correlated with FEV(1)% respectively in BA group (r = -0.663, -0.643, P = 0.026, 0.033). The level of eotaxin in induced sputum is significantly positively correlated with the EOS/Leu % in CAB group (r = 0.658, P = 0.028) and BA group (r = 0.634, P = 0.036), but it is not correlated with any of Neu/Leu %, macrophage (Macro)/Leu % or lymphocyte (Lym)/Leu % in any group (P > 0.05). CONCLUSION: Eotaxin possibly particulates in eosinophilic airway inflammation in patients with BA and CAB by selective chemotactic activity on eosinophil.

Adult↗

PubMed2002

[Differential proteomic analysis of human lung adenocarcinoma cell line A-549 and of normal cell line HBE].

To explore the differential proteomic expressions between human lung adenocarcinoma cell line A-549 and normal cell line HBE, a series of methods, including immobilized pH gradient-two dimensional polyacrylamide gel electrophoresis, silver staining, PDQuest 2-DE software analysis, peptide mass fingerprinting based on matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and SWISS-PROT database searching, were used to separate and identify the differential proteomic expressions between A-549 and HBE. The results showed that the good 2-DE pattern including high resolution and reproducibility was obtained. After silver staining, the 2-DE image analysis by PDQuest 2-DE software detected average (890 +/- 38) spots in A-549, and (757 +/- 27) spots in HBE. The average positional deviation of the matched spots between A-549 and HBE 2-DE maps was (2.85 +/- 0.48) mm in IEF direction, and (2.69 +/- 0.37) mm in SDS-PAGE direction. The differential proteomic expression analysis found that there were 535 matched spots between A-549 and HBE 2-DE maps, 355 spots that were not matched in A-549, 222 spots that were not matched in HBE. 18 differential spots (8 spots in A-549 and 10 spots in HBE) were cut off from silver staining gel at random, digested in gel with TPCK-trypsin, measured with MALDI-TOF-MS and searched in the SWISS-PROT database with PeptIdent software. 18 protein were preliminarily identified. These proteins were related to cell signal transduction, cell metabolism, proliferation and differentiation etc. There was a significant difference at protein level between human lung adenocarcinoma cell line A-549 and normal cell line HBE. It suggests that the differential expression analysis of proteomes may be useful to further study of the related proteins and the molecular markers of lung adenocarcinoma.

Adenocarcinoma↗

PubMed2002

[Construction and expression of a vector containing protein transduction domain and bcr/abl fusion gene].

OBJECTIVE: To construct a vector containing protein transduction domain (PTD) and bcr/abl fusion gene of chronic myelogenous leukemia and express PTD-bcr/abl fusion protein in E. Coli. METHODS: DNA fragment encoding PTD was synthesized and fused to PCR-amplified bcr/abl gene fragment, then inserted into plasmid pET-16b to get the expression vector pEPb containing PTD-bcr/abl fusion gene, which was transfected and expressed in E. Coli LB21. PTD-bcr/abl fusion protein was purified by affinity chromatography. RESULTS: 523 bp bcr/abl fusion gene was effectively amplified. The PTD-bcr/abl gene sequencing showed the same sequence as scheduled. The fusion peptide was successfully expressed in E. Coli and purified. CONCLUSION: The results may provide a new PTD-bcr/abl fusion peptide for the immunotherapy of CML.

Electrophoresis, Polyacrylamide Gel↗

PubMed2002

Synthesis and oxidative refolding of hainantoxin-IV.

Hainantoxin-IV, a neutoxic peptide from the spider Selenocosimia hainana, was synthesized by solid-phase method with fluorenylmethyoxycarbonyl amino acids (Fmoc-AA). Reverse-phase HPLC was used to monitor the oxidative folding of synthetic Hainantoxin-IV under different reaction conditions in order to find optimal conditions for renaturation of synthetic Hainantoxin-IV. The best renaturation yield was received in 5 mmol/L GSH and 0.5 mmol/L GSSG at pH 8.0 in 0.1 mol/L Tris-HCl and 0.1 mol/L NaCl buffer. The renaturated Hainantoxin-IV was monitored with MALDI-TOF MS reverse-phase HPLC and isolated mouse phrenic nerve-diaphragm preparation.

Amino Acid Sequence↗

PubMed2002

[Epidemiological survey on bronchial asthma in Liaoning province].

OBJECTIVE: To survey the prevalence of asthma in urban and rural residents of Liaoning province in 1999 and evaluate the risk factors for asthma, providing data for research and preventive and therapeutic policies for control of asthma. METHODS: Stratified cluster disproportional random sampling survey was performed in 116 276 residents by common protocols and questionnaire. Asthma was diagnosed based upon case history, clinical signs and lung function tests. Univariate analysis was employed to evaluate the risk factors for asthma. RESULTS: The overall prevalence of asthma in Liaoning province was 1.25%, the male to female ratio being 1:1.64. The prevalence of asthma in adults was 1.39% and that in children was 0.48%. The onset of asthma occurring in children under the age of 14 accounted for 38.63% of the whole patients. The prevalence was higher in peasants, animal breeders and government officials. The prevalence in the rural area (1.89%) was higher than that in the urban area (0.81%) (P < 0.01). The prevalence in Shenyang city (1.66%) was higher than those in Dalian city (0.88%) (P < 0.01) and Jinzhou (0.71%) (P < 0.01) city. Risk factor analysis showed that 24.7% of the asthmatics had family history; 20.4% had allergic history, the OR of allergic rhinitis being 6.28; 26.0% had smoking history; the OR of cooking oil smoke exposure was 5.94. Asthmatic attack was induced by influenza, cold air, irritant gases and cooking oil smoke in 52.3% approximately 63.3% of the patients. Asthma induced by exercising, fatigue, emotion and allergy was found in more than 41.3% of the patients. CONCLUSIONS: Our epidemiologic data reflected the general distribution of asthma in Liaoning province. From the overall prevalence rate, it is estimated that there are about 529 700 asthmatics in the whole province. The data will be helpful for the mass prevention and treatment of asthma.

Adolescent↗

PubMed2002

[Rapid separation and determination of enterotoxigenic E. coli by capillary zone electrophoresis].

Rapid separation and determination of enterotoxigenic E. coli K88, K99 and 987P with intact cells using capillary zone electrophoresis (CZE) are described. The CZE was performed in a running buffer of 0.05 mol/L Na2CO3-NaHCO3 (pH 9.9), under applied voltage of 14.1 kV and detected by an on-line UV at 210 nm. Results show that K88, K99 and 987P were separated completely. Moreover, each strain presented a characteristic peak and a reproducible retention time (RSD < or = 0.9%). The successful analysis of enterotoxigenic E. coli in the excrement of diarrhea piglets is also discussed. K88 and K99 were detected in the excrement of diarrhea piglets born in 5 d - 6 d, and 30 d - 35 d respectively, and nothing was detected in the excrement of diarrhea piglets born in about 60 d.

Animals↗

PubMed2001

Reconstruction and Analysis of A Human Small Molecular Antibody to Tumor Necrosis Factor Alpha.

A Fab antibody gene was constructed on the basis of the reconstruction of the linker of a human anti-TNF-alpha ScFv gene. The two ScFvs before and after reconstruction were cloned into expression vector pBV220. About 30 kD recombinant proteins were expressed by induction and they constituted 6.5% and 13.8% of the total bacterial protein, respectively. A soluble Fab expression vector was constructed and transformed into E.coli HB2151.After induction by IPTG, a new protein band about 50 kD appeared on SDS-PAGE. The expressed ScFv and Fab were purified from E.coli lysates, and further experiments showed that 1) the expression amount of reconstructed ScFv was increased distinctly 2) ScFv and Fab could bind rhTNF-alpha. The ScFv containing GGGGS had an affinity constant of 6.70x10(4)(mol/L)(-1), and the ScFv containing (GGGGS) (3) had an affinity constant of 7.27x10(5) (mol/L) (-1).The affinity constant of Fab was 7.61x10(5) (mol/L) (-1). The Fab and reconstructed ScFv was indifferent in affinity activity 3) ScFv and Fab neutralized the cytotoxicity of rhTNF-alpha. The neutralizing ability of Fab was the same as the reconstructed ScFv, but lower than a mouse anti-TNF-alpha mAb. These data may be helpful for using human anti-TNF-alpha small molecular Ab in antagonizing the activity of TNF-alpha in therapy.

Journal Article↗

PubMed2000

Identification of Protein Spots in Silver-stained Two-dimensional Gels by MALDI-TOF Mass Peptide Map Analysis.

Protein spots in silver-stained two dimensional gels were analyzed and identified by employing an improved procedure of mass spectrometric peptide mapping, including i) In-gel reduction, alkylation and enzymatic digestion ii) Extraction and desalting by using a pipette tip containing a small C18 micro-column (ZipTip(TM)) iii) Direct MALDI-TOF mass analysis and protein database searching. The results demonstrate that single silver-stained protein spots in a 2-DE-gel could be identified rapidly by this procedure and the use of the ZipTip(TM) pipette tip could increase evidently the sensitivity of the MALDI-TOF analysis. By using this the procedure, 10 protein spots in a silver-stained gel of 2-DE of crude venom of the spider S.Huwena were analyzed and identified.

Journal Article↗

PubMedDate not supplied

A novel long-chain acyl-derivative of epigallocatechin-3-O-gallate prepared and purified from green tea polyphenols.

Lipophilic tea polyphenols (LTP) were prepared by catalytic esterification of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-chain acyl-derivative of epigallocatechin-3-O-gallate (EGCG) was first isolated from purification of LTP by high-speed countercurrent chromatography (HSCCC) using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v). The molecular structure of the acyl-derivative, Epigallocatechin-3-O-gallate-4'-O-hexadecanate, was elucidated by means of elemental analysis, IR, (1)H-NMR and MS spectra

Acylation↗