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Biomedical subjects

Q Song

Publications and source records attributed to Q Song.

At least 19 recordsLinked to original sources
PubMed2003

20E-regulated USP expression and phosphorylation in Drosophila melanogaster.

The developmental profiles of ultraspiracle protein (USP) in the tissues of Drosophila melanogaster were investigated using a USP specific monoclonal antibody (mAb) as a probe. Western blot analysis revealed four USP mAb reactive bands (p46, p48, p54 and p56), each with tissue- and stage-specific expression patterns. The p54 and p56 were expressed in nearly all larval and prepupal tissues tested with fluctuations in abundance. However, the p46 and p48 were detected exclusively in the midgut of prepupae and shown to be the proteolytic products of p54 and p56. A lambda protein phosphatase assay demonstrated that the p56 is the phosphorylated form of p54. The expression and phosphorylation of the p54 USP is regulated by 20E. Protein kinase consensus recognition sequence analysis revealed 10 putative phosphorylation sites in Drosophila USP, with seven sites for protein kinase C (PKC) and three sites for casein kinase II (CKII). The fact that seven out of 10 putative phosphorylation sites reside in the ligand- and DNA-binding domains suggests that phosphorylation may play important role in regulating USP function. Identification of the in vivo USP phosphorylation sites and signal transduction pathways that regulate the specific USP phosphorylation is currently underway.

Animals↗
PubMed2003

Effects of ecdysone agonists on the expression of EcR, USP and other specific proteins in the ovaries of the codling moth (Cydia pomonella L.).

Tebufenozide and methoxyfenozide have been previously shown to significantly reduce fecundity and cause vitellogenin accumulation in hemolymph of the codling moth Cydia pomonella L. In the present study, the effects of these ecdysone agonists, tebufenozide and methoxyfenozide, on the expression of ecdysone receptor (EcR), ultraspiracle protein (USP) and other proteins in the ovaries of C. pomonella L., were investigated at both the translational and/or transcriptional levels with an aim to elucidate the mechanisms by which the fecundity was reduced. Western and Northern blot analyses revealed that the expression of a 65 kDa (p65) EcR, and 60 and 64 kDa (p60 and p64) USP proteins were enhanced by tebufenozide and methoxyfenozide at both transcriptional and translational levels. Northern blot analysis indicated that the p65 EcR protein is encoded by EcRB1 transcript and that the p60 and p64 USP bands were the products of USP-1 transcript. Immunoprecipitation assays demonstrated that both the p60 and p64 USP coprecipitated with the p65 EcR and that p64 was a dominant USP to form complex with EcR. In addition, several other specific proteins were also identified and their expressions affected by the agonists. The data suggest that the ecdysone agonists regulate, via the EcR/USP complex, the expression of these specific proteins that might eventually lead to the inhibition of fecundity in the codling moth.

Animals↗
PubMed2003

An intelligent controller for automated operation of sequencing batch reactors.

In this paper the results are presented of original research into the automatic and "intelligent" detection of breakpoints in Dissolved Oxygen (DO) profiles. The research has been based on a large body of data collected from laboratory SBRs operating on synthetic wastewater. Two different approaches were followed to identify the endpoints. The paper analyses and evaluates the results of automatic detection on the basis of geometric features in the DO profiles. This was followed by classification of the detected breakpoints using different soft computing techniques based on Neural Network (NN), Fuzzy Neural Network (FuNN) and Evolving Fuzzy Neural Network (EfuNN) software systems for breakpoint classification. A high rate of successful detection and classification was obtained with up to 96% of the decisions made correctly. In order to overcome the limitations of this system to adapt to dynamically changing process conditions, an intelligent control model was developed by a combination between an Evolving Fuzzy Neural Net (EfuNN) combined with a logic decision unit. This system has the ability to "learn on-the-fly" and adjust its response pattern in order to maintain a high rate of successful breakpoint detection under varying changing process conditions. This software system has been sucessfully embedded on a small programmable controller for integration into larger process control systems for the operation of SBR plants.

Automation↗
PubMed2001

Nuclear translocation of PDCD5 (TFAR19): an early signal for apoptosis?

The programmed cell death 5 (PDCD5) protein is a novel protein related to regulation of cell apoptosis. In this report, we demonstrate that the level of PDCD5 protein expressed in cells undergoing apoptosis is significantly increased compared with normal cells, then the protein translocates rapidly from the cytoplasm to the nucleus of cells. The appearance of PDCD5 in the nuclei of apoptotic cells precedes the externalization of phosphatidylserine and fragmentation of chromosome DNA. This phenomenon is parallel to the loss of mitochondrial membrane potential, independent of the feature of apoptosis-inducing stimuli and also independent of the cell types and the apoptosis modality. In conclusion, the nuclear translocation of PDCD5 is a universal earlier event of the apoptotic process, and may be a novel early marker for apoptosis.

Active Transport, Cell Nucleus↗
PubMed2001

Platelet-derived growth factor promotes the expression of peroxisome proliferator-activated receptor gamma in vascular smooth muscle cells by a phosphatidylinositol 3-kinase/Akt signaling pathway.

Vascular diseases such as atherosclerosis are characterized by abnormal accumulation of vascular smooth muscle cells (VSMCs) within the intimal lining. The intimal VSMCs exhibit an increased expression of peroxisome proliferator-activated receptor gamma (PPARgamma), and the administration of pharmacological PPARgamma agonists attenuates vascular lesion formation. The factors that regulate PPARgamma expression in the vasculature are poorly defined. Here we report that platelet-derived growth factor (PDGF) upregulates PPARgamma by the phosphatidylinositol 3-kinase (PI3-kinase)/Akt signaling pathway. Using Northern-blotting and Western-blotting analyses, we observed that the levels of PPARgamma mRNA and protein were increased by 2- to 3.5-fold in human aortic smooth muscle cells (HASMCs) treated with PDGF (20 ng/mL). This was abolished by preincubation of HASMCs with a PI3-kinase inhibitor (LY294002, 50 micromol/L), and partially inhibited by a MEK1 inhibitor (U0126, 10 micromol/L), but not affected by a p38 kinase inhibitor (SB202190, 10 micromol/L). In addition, overexpression of the dominant-negative p85 subunit of PI3-kinase or Akt proteins blocked the PDGF-induced PPARgamma expression. Taken together, our results suggest that PDGF induces PPARgamma expression in VSMCs by a PI3-kinase/Akt signaling pathway. The characterization of factors and signaling pathways that modulate PPARgamma expression in VSMCs may have important implications for understanding the pathogenesis of vascular diseases.

Aorta↗
PubMed2001

Quantitation of promethazine and metabolites in urine samples using on-line solid-phase extraction and column-switching.

A chromatographic method for the quantitation of promethazine (PMZ) and its three metabolites in urine employing on-line solid-phase extraction and column-switching has been developed. The column-switching system described here uses an extraction column for the purification of PMZ and its metabolites from a urine matrix. The extraneous matrix interference was removed by flushing the extraction column with a gradient elution. The analytes of interest were then eluted onto an analytical column for further chromatographic separation using a mobile phase of greater solvent strength. This method is specific and sensitive with a range of 3.75-1400 ng/ml for PMZ and 2.5-1400 ng/ml for the metabolites promethazine sulfoxide, monodesmethyl promethazine sulfoxide and monodesmethyl promethazine. The lower limits of quantitation (LLOQ) were 3.75 ng/ml with less than 6.2% C.V. for PMZ and 2.50 ng/ml with less than 11.5% C.V. for metabolites based on a signal-to-noise ratio of 10:1 or greater. The accuracy and precision were within +/- 11.8% in bias and not greater than 5.5% C.V. in intra- and inter-assay precision for PMZ and metabolites. Method robustness was investigated using a Plackett-Burman experimental design. The applicability of the analytical method for pharmacokinetic studies in humans is illustrated.

Humans↗
PubMed2001

Molecular cloning and characterization of chemokine-like factor 1 (CKLF1), a novel human cytokine with unique structure and potential chemotactic activity.

Cytokines are small proteins that have an essential role in the immune and inflammatory responses. The repertoire of cytokines is becoming diverse and expanding. Here we report the identification and characterization of a novel cytokine designated as chemokine-like factor 1 (CKLF1). The full-length cDNA of CKLF1 is 530 bp long and a single open reading frame encoding 99 amino acid residues. CKLF1 bears no significant similarity to any other known cytokine in its amino acid sequence. Expression of CKLF1 can be partly inhibited by interleukin 10 in PHA-stimulated U937 cells. Recombinant CKLF1 is a potent chemoattractant for neutrophils, monocytes and lymphocytes; moreover, it can stimulate the proliferation of murine skeletal muscle cells. These results suggest that CKLF1 might have important roles in inflammation and in the regeneration of skeletal muscle.

Amino Acid Sequence↗
PubMed2001

Volatiles from Ficus hispida and their attractiveness to fig wasps.

Volatile compositions of receptive (ready to be pollinated), postpollinated, and postparasitized figs. and leaves of Ficus hispida were analyzed. Differences among them were examined, and the specificity of fig wasp attractiveness was investigated. Linalool was the major constituent of steam-distilled oil of either male or female receptive figs, while dibutyl phthalate was the major compound of the oils of postparasitized and postpollinated figs. In petroleum ether extracts, palmitic oil, and 9,12-octadecadienoic acid were the main constituents of male and female receptive figs, while hexadecanoic acid ethyl ester was the major compound of postparasitized and postpollinated figs. In dichloromethane extracts, linalool was the major constituent of male and female receptive figs, 1-hydroxylinalool was the major component of male postparasitized figs, and 1-hydroxylinalool and benzyl alcohol were the major constituents of female postpollinated figs. Bioassays with sticky traps showed that Ceratosolen solmsimarchal was attracted to dichloromethane extracts of male and female receptive figs and to petroleum ether extracts of female receptive figs, but was not attracted to dichloromethane and petroleum ether extracts of male postparasitized and female postpollinated figs. Figs were attractive to pollinating wasps only at the receptive stage. The volatile constituents of receptive figs were different from those of postpollinated or postparasitized figs. From a receptive to a postpollinated state, figs changed in their volatile composition. Some compounds disappeared or decreased in amount. These include linalool, linalool oxide, alpha-terpeneol, and 2,6-dimethyl-1,7-octadiene-3,6-diol, which may act as the attractants of the wasps. Others increased in amount, or several additional chemicals appeared. These include dibutyl phthalate, 1-hydroxylinalool, and benzyl alcohol, which may be repellents of the wasps. That dichloromethane extracts of male and female receptive figs showed similar activities in attracting fig wasps indicates that receptive figs of both sexes are similarly attractive to fig wasps, which is further supported by their similar volatile composition. Leaf extract was not attractive to the wasps.

Animals↗
PubMed2001

Tris(2,2'-bipyridine)ruthenium(II) electrogenerated chemiluminescence of alkaloid type drugs with solid phase extraction sample preparation.

An electrogenerated chemiluminescence (ECL) method for the determination of pethidine, atropine, homatropine and cocaine is described. The optimum conditions were found to be similar for all of these compounds although the ECL emission intensity for cocaine was an order of magnitude lower than for pethidine due to their different chemical structures. Linear calibrations were obtained for all the compounds at pH 10 in borate buffer (0.05 mol l-1) at 1.3 V. Limits of detection of 6.8 x 10(-8), 2.2 x 10(-7), 3.2 x 10(-7) and 6.5 x 10(-7) mol l-1, respectively, were achieved for pethidine, atropine, homatropine and cocaine in standard solutions. Solid-phase extraction was used to separate the drugs from their matrix and the method was applied to the determination of spiked urine samples. The limits of quantitation for pethidine, atropine, homatropine and cocaine in urine were 1.0 x 10(-6), 2.0 x 10(-6), 2.0 x 10(-6) and 4.0 x 10(-6) mol l-1, respectively, with recoveries of between 90 and 110%.

Alkaloids↗
PubMed2001

Phospholipase C activity of Helicobacter pylori is not associated with the presence of the cagA gene.

BACKGROUND: Knowledge about the possible role of phospholipase C (PLC) activity of microbial pathogens in the development of disease is increasing. Recently attention has focused on investigating PLC activity elaborated by Helicobacter pylori, but the role of this enzyme in H. pylori pathogenesis is still unknown. The aim of this study was to correlate PLC-activity of H. pylori on the basis of the cagA status with the clinical diagnosis of the patients. MATERIALS AND METHODS: Helicobacter pylori was isolated from patients with gastritis (G; n = 38), duodenal ulcer (DU; n = 15), gastric ulcer (GU; n = 11) and gastric cancer (GC; n = 12). Polymerase chain reaction primers DZ3/R009 which amplified a 1350-bp fragment were used to detect the cagA gene. PLC activity was determined using p-nitrophenylphosphorylcholine as substrate. RESULTS: Of the strains, 60% were cagA(+) and 40% were cagA(-). All strains showed PLC activity (2.20 +/- 0.91 U mg(-1) protein). PLC activity showed no association with the cagA status: cagA(+) (2.21 +/- 1.03 U mg(-1) protein), cagA(-) (2.18 +/- 0.79 U mg(-1) protein). Patients with GU had the highest PLC activity (2.77 +/- 1.26 U mg(-1) protein) and patients with GC had the lowest activity (1.8 +/- 0.57 U mg(-1) protein). CONCLUSIONS: Although PLC activity was present in all strains tested, it may only have pathological importance in patients with GU. However, the extent of PLC activity was independent of the presence of the cagA gene.

Adenocarcinoma↗
PubMed2001

Characteristics of Helicobacter pylori infection in Jamaican adults with gastrointestinal symptoms.

Helicobacter pylori infection is common in Jamaica. Describing its epidemiology in a population-based study depends largely on serology, but serologic assays have not been validated in this population. To address this issue, we examined the presence of H. pylori infection in 30 sequential adult patients with gastroduodenal symptoms by three biopsy-based methods (rapid urease test, histology, and culture) as well as by one research and two commercial enzyme-linked immunosorbent assays (ELISAs). A patient was considered H. pylori positive if the organism was detected by at least one biopsy-based method. Eighteen (60%) of the 30 patients were H. pylori positive by these criteria, whereas 21 (70%) were seropositive for H. pylori immunoglobulin G by our research ELISA. The presence of H. pylori infection in patients with gastric cancer and those with chronic gastritis was missed by biopsy-based methods but was detected by serologic assays. This observation indicates that serologic assays may be better suited for the detection of this infection in a population in which H. pylori-associated pathology is prevalent. The performance of our research ELISA in detecting biopsy-based H. pylori-positive cases was excellent, with a sensitivity and specificity of 100% and 75%, respectively. Molecular genotyping of the isolates revealed that the predominant H. pylori genotypes in this cohort of Jamaicans were cagA(+) vacA slb-m1, and iceA2. The validated serologic assay enables us to interpret epidemiologic data from population-based studies in Jamaica by comparison to those from other populations.

Adult↗
PubMed2001

Genotypic, clinical, and demographic characteristics of children infected with Helicobacter pylori.

Helicobacter pylori isolates vary between geographic regions. Certain H. pylori genotypes may be associated with disease outcome. Thirty-eight children underwent diagnostic upper endoscopy at four medical centers and were retrospectively analyzed to determine if H. pylori virulence genes were associated with endoscopic disease severity, histologic parameters, and host demographics. The H. pylori virulence genotype was analyzed by a reverse hybridization line probe assay and type-specific PCR. Endoscopic ulcers or erosions were found in 17 (45%) patients, with 13 (34%) of these patients having antral nodularity. Histological gastritis, of varying severity, was present in all children. Four patients harbored more than one H. pylori strain: one subject had both cagA(+) and cagA-negative strains, while three patients harbored either two different cagA-negative strains (two children) or two cagA(+) strains (one child). There were 28 (74%) cagA(+) isolates; 19 were associated with the vacA s1b genotype, 7 were associated with the vacA s1a genotype, 1 was associated with the vacA s1c genotype, and 1 was associated with the s2 genotype. Of 14 cagA-negative isolates, 6 were vacA s2 genotype, 4 were vacA s1b, 3 were vacA s1a, and 1 was vacA s1c. Nine of ten (90%) Hispanics had similar H. pylori strains (vacA s1b,m1), and all Asian-Canadian children were infected by strains with vacA s1c genotype. No correlation between H. pylori strain and endoscopic or histopathologic abnormalities was found. This study provides a baseline framework of North American children and their H. pylori strains, serving as a powerful epidemiological tool for prospective investigations to better understand the transmission and evolution of diverse disease outcomes.

Adolescent↗
PubMed2001

Recombinant single chain cardiac troponin I-C polypeptides: superior calibration and control materials for cardiac troponin I immunoassays.

There has been a need to create stable and reproducible calibration and control materials for cardiac troponin I assays. Free troponin I, native or recombinant, has been known to be unstable, while troponin CI complex can be easily dissociated in low concentrations or in the presence of chelating agents. In order to overcome these difficulties, two single chain troponin I-C polypeptides have been engineered and expressed separately in Escherichia coli. One consists of a full-length of human cardiac troponin I and C, termed as ScTnI-C and the other consists of a stable fragment (aa28-110) of human cardiac troponin I and a full-length troponin C, termed as ScTnI-C-2. Both ScTnI-C and ScTnI-C-2 were purified to homogeneity by affinity chromatography using anti-cTnI monoclonal antibodies. ScTnI-C and ScTnI-C-2 have apparent molecular weights of 45 kD and 30 kD by SDS-PAGE, respectively. Stability studies by Stratus showed that ScTn I-C and ScTnI-C-2 were stable for 4 months at 2-8 degrees C and at least one year at -20 degrees C. When incubated in human serum at 37 degrees C, ScTnI-C-2 was more resistant to proteolysis than ScTnI-C. ScTnI-C can be recognized by all commercial TnI immunoassays with excellent activity. ScTnI-C-2 can be recognized by all immunoassays that target the stable region of cardiac troponin I. Judging by their performances, ScTnI-C and ScTnI-C-2 are both superior materials to be used as calibrators and controls in clinical laboratories.

Antibodies, Monoclonal↗
PubMed2001

[Effective factors of flocculation-DAF pilot process treating water with low temperature and low turbidity from Miyun reservoir].

The hydraulic parameters in coagulation, flocculation and flotation units of DAF pilot process were systematically investigated when employing flocculants AS and PAC respectively. In general, the available parameters for PAC are more favorable in DAF process. For PAC as a flocculant during DAF run, the favorable coagulation rapid mixing time is 15 s, the flocculant mixing time is no less than 5 minutes. However for AS, the corresponding time values are greater than 30 s and more than 7.5 minutes respectively. The available coagulation mixing intensity is 300-1000 s-1. The available flocculation mixing intensity (average G) is 40-140 s-1, and the GT (average) value is greater than 2 x 10(4). Both equal-speed mixing and two or three stages mixing could provide slight better turbidity removal. For MJ model nozzle, the suitable recycle ratio is 5.0%-8.3% at dispersed pressure of 2.5-3.3 kg.cm2. The detention time and hydraulic intensity in contact zone of DAF tank have important effects on DAF turbidity removal.

Flocculation↗
PubMed2001

[Effect of plastic film mulching on crop yield and nitrogen efficiency in semiarid areas].

The effect of plastic film mulching, water storage in soil profile before sowing, and nitrogen fertilization on crop yield and nitrogen efficiency was examined in this paper. The study site was on the cultivated lossial soil in semiarid areas with 415 mm of annual rainfall and the test crop was spring wheat, Triticum aestivum. In order to study the effect of plastic film mulching, 4 levels of mulching were designed, including mulching of 0, 30 and 60 days after sowing and mulching over the whole growing period. The results showed that increase of soil water storage, plastic film mulching and nitrogen fertilization increased crop yield significantly(alpha < 0.01), and their effect followed in the order of nitrogen fertilization > increase of water storage > plastic film mulching. The effect of mulching on crop yield varied with water storage, nitrogen fertilization and mulching periods. When the water storage was low, there was no significant difference in crop yield between mulching and no mulching, although mulching increased crop yield slightly, and the nitrogen efficiency was higher for no mulching and mulching 30 days. When the water storage was high, the difference between the yield of mulching 60 days and no mulching was significant, but no difference in nitrogen efficiency was found for mulching 30 days, 60 days and over whole growing period. It was suggested that mulching over whole growing period was of less significance in practice.

Crops, Agricultural↗
PubMed2001

[Expression of cytokeratin 7 and 20 in ovarian metastatic carcinomas].

OBJECTIVE: To study the distinctive clinicopathologic and immunohistochemical difference between ovarian metastatic carcinomas and primary ovarian carcinomas. METHODS: The clinical and pathological features of 27 cases of ovarian metastatic carcinomas (gastric carcinomas 12 cases, colon carcinomas 11 cases, others 4 cases) obtained from our department were reviewed. Immunostainings for CK (AE1/AE3), CK7, CK20, CEA, vimentin, nm23 were performed with SP staining methods. RESULTS: On gross examination, metastasis from gastric adenocarcinoma were usually bilateral, while solid (11/12) and metastases from colonic adenocarcinoma were more often unilateral and cystic (7/11). Microscopically, metastases from gastric adenocarcinoma revealed signet ring cells or poorly differentiated adenocarcinomas (12/12), whereas metastases from colonic adenocarcinomas showed similar morphology of endometrioid adenocarcinoma (8/11). The majority of ovarian metastases of gastric carcinoma (7/12) and colon carcinoma (8/11) were CK20 positive. In particular, CK20 was invariably expressed in colon cancer metastases. Most of the ovarian metastatic carcinomas from the gastrointestinal tract failed to react with immunostaining of CK7. A combined use of CEA, vimentin and nm23 had made a correct classification for 11/12 cases of the gastric carcinoma, 10/11 cases of the colonic cancer. CONCLUSIONS: CK7 and CK20 have been proved to be useful antibodies in distinguishing between metastatic carcinomas and primary carcinomas of the ovary. Combined use of a panel of antibodies can give more significant results.

Adenocarcinoma↗