Biomedical subjects

Q Zhang

Publications and source records attributed to Q Zhang.

At least 19 recordsLinked to original sources

PubMed2003

Coal-induced interleukin-6 gene expression is mediated through ERKs and p38 MAPK pathways.

In the present study, we have tested the ability of coal dust to stimulate kinase phosphorylation of activator protein-1 (AP-1) signal transduction pathways and production of interleukin-6 (IL-6) in both mouse epidermal JB6 and human lung epithelial A549 cells. Seven coal samples from three coalmine regions of Pennsylvania (PA), West Virginia (WV), and Utah (UT) with high, medium, and low prevalence of coal workers' pneumoconiosis (CWP), respectively, were investigated. Results from the present study indicate that three PA coals stimulated the mitogen-activated protein kinase (MAPK) family of extracellular signal-regulated kinases (ERKs) and p38 MAPK, but not c-Jun-NH2-terminal kinases (JNKs) in human lung A549 cells. The effects of three UT coals on the kinase phosphorylation were less as compared to those of the PA coals. Coal dusts from three coalmine regions induced IL-6 in a dose-dependent manner in both JB6 and A549 cells. Interestingly, levels of IL-6 in both cells treated with coals from three coalmine regions correlated well with CWP prevalence from that region. To assess the role of AP-1 pathways in coal-mediated transcriptional activation of IL-6, various inhibitors were used in cells treated with one PA coal, which induced a maximal response. It was found that the increase in IL-6 protein and mRNA by the PA coal was completely eliminated by the pretreatment of both cell types with PD98059, a specific MEK1 inhibitor, and SB202190, a p38 kinase inhibitor. Our results indicate that coal dust can stimulate IL-6 release from mouse epidermal JB6 cells and human lung epithelial A549 cells, and the coal-induced IL-6 increase may involve ERKs and p38 MAPK pathways.

Animals↗

PubMed2003

Genetic and physical mapping of a new gene for bacterial blight resistance in rice.

The inheritance of resistance for bacterial blight, caused by Xanthomonas oryzae pv. oryzae ( Xoo), was studied in Minghui 63, an elite restorer line for a number of widely used rice hybrids in China. A new dominant gene against a Chinese Xoo strain JL691 in both the seedling and adult stages was identified in Minghui 63 and designated as Xa26( t). Using a total of 477 highly susceptible individuals from an F(2) population, the Xa26( t) locus was mapped to a region of about 1.68 cM. This locus co-segregated with marker R1506 and was 0.21 cM from marker RM224 on one side and 1.47 cM from marker Y6855RA on the other side, in rice chromosome 11. A contig map, composed of five non-redundant bacterial artificial chromosome (BAC) clones and spanning approximately 500 kb in length, was constructed. Analysis of recombination events in the Xa26( t) region with the highly susceptible F(2) individuals anchored the gene locus to a region covered by three overlapped BAC clones. Assay of the lines showing a double crossover in marker loci flanking Xa26( t), in a population of recombinant inbred lines carrying Xa26( t), further delineated the gene to a 20-kb fragment. The Xa26( t) locus is tightly linked to another bacterial blight resistance gene locus, Xa4.

Chromosomes, Artificial, Bacterial↗

PubMed2003

Induction of interleukin-6 by coal containing bioavailable iron is through both hydroxyl radical and ferryl species.

Coal mining causes health problems, such as pneumoconiosis. We have previously shown that prevalence of pneumoconiosis in workers from various coalmine regions positively correlates with levels of bioavailable iron (BAI) in the coals from that region. In the present study, the nature of reactive oxygen species formed by BAI in the coals and its mechanisms of the induction of biological responses were investigated. Human lung epithelial cell line, A549 cells, were used to examine the induction of interleukin-6 (IL-6), a pro-inflammatory cytokine, which is known to play a crucial role in the development of pneumoconiosis. We found that levels of IL-6 protein as well as its mRNA were significantly increased in the cells treated for 24 h with 20 microg/cm2 of the BAI-containing Pennsylvania (PA) coal; for example we observed 6.7-fold increase in IL-6 protein. Levels of IL-6 protein in cells treated with the Utah (UT) coal containing low-BAI were only 1.9-fold of the control levels. The enhancing effect on the IL-6 by the PA coal was similar to that caused by hydrogen peroxide. Superoxide dismutase (SOD), catalase (CAT), and N-acetyl-L-cysteine (NAC) all had inhibitory effects on the PA coal-induced IL-6 formation. However, CAT had the least protective effect as compared to SOD and NAC. Our results indicate that BAI in the PA coal may induce IL-6 through both ferryl species (via iron autoxidation) and hydroxyl radicals (via the Fenton/Haber Weiss reactions).

Acetylcysteine↗

PubMed2003

Cytological evidence for preservation of mitochondrial and plastid DNA in the mature generative cells of Chlorophytum spp. (Liliaceae).

Following 4',6-diamidino-2-phenylindole staining of mature pollen grains of Chlorophytum comosum, fluorescence microscopy confirmed that cytoplasmic nucleoids (DNA aggregates) were present in the generative cells, which indicated the possibility of biparental cytoplasmic inheritance. Electron and immuno-electron microscopy showed that both plastids and mitochondria were present in the generative cells, and both organelles contained DNA. These results indicate that mitochondria and plastids of C. comosum have the potential for biparental inheritance. Similar results were obtained with mature pollen grains of C. chinense. Therefore, we conclude the coincident biparental inheritance for mitochondria and plastids in the members of the genus Chlorophytum.

DNA, Mitochondrial↗

PubMed2003

Delivery of radiofrequency energy to the lower oesophageal sphincter and gastric cardia inhibits transient lower oesophageal sphincter relaxations and gastro-oesophageal reflux in patients with reflux disease.

BACKGROUND AND AIMS: Radiofrequency energy (RFe) treatment to the lower oesophageal sphincter (LOS) and gastric cardia is a new luminally delivered therapy proposed as an alternative treatment for gastro-oesophageal reflux disease (GORD). However, it is unclear how RFe achieves its antireflux effect. This study investigated the effects of RFe on mechanisms of spontaneous reflux in patients with GORD. METHODS: Twenty patients with GORD underwent endoscopy, symptom evaluation, and combined postprandial oesophageal manometry and pH monitoring before and six months after RFe, and 24 hour ambulatory pH monitoring before and at six and 12 months after treatment. RESULTS: RFe reduced the rate of postprandial transient LOS relaxations from 6.8 (5.7-8.1) (median (interquartile range) per hour to 5.2 (4.2-5.8) per hour (p<0.01), and increased mean basal LOS pressure from 5.2 (SEM 0.3) mm Hg to 8.0 (SEM 0.4) mm Hg (p<0.01). The number of reflux events was reduced from 10 (2-15.3)/3 hours to 5 (3.5-8.5)/3 hours (p<0.05) and there was an associated significant reduction in acid exposure time from 5.4% (0.4-14.7) to 3.9% (0.4-6.6) (p<0.05). RFe significantly reduced ambulatory oesophageal acid exposure from 10.6% (7.8-13.0) to 6.8% (3.1-9.1) (p<0.01) at six months and 6.3% (4.7-10.9) (p<0.05) at 12 months. All patients required acid suppressant medication for symptom control before RFe. Six months after treatment, 15 patients (75%) were in symptomatic remission and 13 (65%) at 12 months. CONCLUSIONS: RFe has significant effects on LOS function that are associated with improvement in the antireflux barrier. Uncontrolled clinical data also suggest a beneficial effect in the control of reflux symptoms in these patients.

Adult↗

PubMed2003

High prevalence of left ventricular systolic and diastolic asynchrony in patients with congestive heart failure and normal QRS duration.

OBJECTIVE: To study the possible occurrence of left ventricular (LV) systolic and diastolic asynchrony in patients with systolic heart failure (HF) and narrow QRS complexes. DESIGN: Prospective study. SETTING: University teaching hospital. PATIENTS: 200 subjects were studied by echocardiography. 67 patients had HF and narrow QRS complexes (< or = 120 ms), 45 patients had HF and wide QRS complexes (> 120 ms), and 88 served as normal controls. INTERVENTIONS: Echocardiography with tissue Doppler imaging was performed using a six basal, six mid-segmental model. MAIN OUTCOME MEASURES: Severity and prevalence of systolic and diastolic asynchrony, as assessed by the maximal difference in time to peak myocardial systolic contraction (T(S)) and early diastolic relaxation (T(E)), and the standard deviation of T(S) (T(S)-SD) and of T(E) (T(E)-SD) of the 12 LV segments. RESULTS: The mean (SD) maximal difference in T(S) (controls 53 (23) ms v narrow QRS 107 (54) ms v wide QRS 130 (51) ms, both p < 0.001 v controls) and in T(S)-SD (controls 17.0 (7.8) ms v narrow QRS 33.8 (16.9) ms v wide QRS 42.0 (16.5) ms, both p < 0.001 v controls) was prolonged in the narrow QRS group compared with normal controls. Similarly, the maximal difference in T(E) (controls 59 (19) ms v narrow QRS 104 (71) ms v wide QRS 148 (87) ms, both p < 0.001 v controls) and in T(E)-SD (controls 18.5 (5.8) ms v narrow QRS 33.3 (27.7) ms v wide QRS 48.6 (30.2) ms, both p < 0.001 v controls) was prolonged in the narrow QRS group. The prevalence of systolic and diastolic asynchrony was 51% and 46%, respectively, in the narrow QRS group, and 73% and 69%, respectively, in the wide QRS group. Stepwise multiple regression analysis showed that a low mean myocardial systolic velocity from the six basal LV segments and a large LV end systolic diameter were independent predictors of systolic asynchrony, while a low mean myocardial early diastolic velocity and QRS complex duration were independent predictors of diastolic asynchrony. CONCLUSIONS: LV systolic and diastolic mechanical asynchrony is common in patients with HF with narrow QRS complexes. As QRS complex duration is not a determinant of systolic asynchrony, it implies that assessment of intraventricular synchronicity is probably more important than QRS duration in considering cardiac resynchronisation treatment.

Aged↗

PubMed2003

Macrophage migration inhibitory factor expression is increased in pituitary adenoma cell nuclei.

Macrophage migration inhibitory factor (MIF) is an essential regulator of the macrophage responses to endotoxin. MIF also has the ability to override the anti-inflammatory actions of glucocorticoids during an immune response, and is thus an important pro-inflammatory factor. The presence of MIF in cells of the anterior pituitary has been described, and high levels of MIF in other rapidly proliferating tIssues have also been demonstrated. It has been hypothesised that MIF release from these cells is influenced by the hypothalamo-pituitary-adrenal axis, and that ACTH and MIF are released simultaneously to exert counter-regulatory effects on cortisol. However, another intracellular role for MIF has also been suggested as it has been shown that MIF exerts an effect on the inhibitory cell cycle control protein p27 through an interaction with Jab1, a protein implicated in p27 degradation. We studied MIF expression in different normal and adenomatous human pituitary samples using immunohistochemistry and RT-PCR. There was evidence of co-immunoprecipitation of MIF with Jab1, suggesting an interaction of the two proteins. Our results showed that there is increased expression of MIF protein in the nuclei of all pituitary adenomas compared with normal tIssue (P=0.0067), but there was no statistically significant difference in nuclear MIF expression between the different adenoma types. Nuclear MIF expression correlated positively with p27 and its phosphorylated form in normal tIssue (P=0.0028 and P<0.0001); however, this relationship was not seen in the adenoma samples. Cytoplasmic expression of MIF was found to be variable both in normal and adenomatous samples, with no consistent pattern. MIF mRNA was demonstrated to be present in all tumour and normal samples studied. Somatotroph tumours showed higher MIF mRNA expression compared with normal pituitary or other types of adenomas. In conclusion, MIF is expressed in cell nuclei in pituitary adenomas to a greater extent than in normal pituitary tIssue. We speculate that it may play a role in the control of the cell cycle, but whether its higher level in adenomas is a cause or a consequence of the tumorigenic process remains to be clarified.

Adenoma↗

PubMed2003

Characterization of two labor-induced genes, DSCR1 and TCTE1L, in the pregnant ovine myometrium.

In the present study we characterized two labor-induced genes, DSCR1 (Down syndrome candidate region 1) and TCTE1L (murine t-complex like), which were identified by suppression subtractive hybridization in the pregnant ovine myometrium. DSCR1 and TCTE1L cDNA sequences were retrieved from a custom-made labor-myometrial cDNA library by hybridization screening. The characterized cDNA sequences include 5'-untranslated region (UTR), coding region and 3'-UTR, which are 12 bp, 351 bp and 1716 bp for TCTE1L, and 64 bp, 594 bp and 1539 bp for DSCR1 respectively. The two cDNA sequences encode proteins of 116 and 197 amino acids for TCTE1L and DSCR1 respectively. Northern analysis further confirmed the significant increases of myometrial DSCR1 and TCTE1L mRNA associated with spontaneous term labor (n=6) compared with gestation-matched controls not in labor (n=6). The abundance of DSCR1 and TCTE1L mRNA was attenuated when myometrial contraction was inhibited by Nimesulide (n=6), a specific prostaglandin H synthase 2 inhibitor. Fetal occupancy greatly upregulated DSCR1 and TCTE1L mRNA in the gravid horn during betamethasone-induced premature labor (n=6) compared with the non-gravid horn not in labor (n=3). Estradiol upregulated TCTE1L mRNA, but had no effect on DSCR1 mRNA expression in the non-pregnant sheep myometrium. Progesterone alone had no effect on both DSCR1 and TCTE1L mRNA expression, however progesterone antagonized estradiol's stimulating effect on myometrial TCTE1L mRNA expression in ovariectomized non-pregnant sheep. Upregulation of DSCR1 and TCTE1L in both betamethasone-induced premature labor and spontaneous term labor and inhibition of their expression by Nimesulide suggest a functional role of these two genes in myometrial activation associated with onset of labor. Mechanical stretch, labor and steroids differentially regulated DSCR1 and TCTE1L mRNA in the pregnant and non-pregnant sheep myometrium.

Amino Acid Sequence↗

PubMed2003

Effect of nitrous oxide on intracellular events of GT1-7 GnRH-secreting neurons.

Exposure to nitrous oxide (N2O) may result in decreased fertility and other reproductive problems in women working in dental offices. This study explored direct effects of N2O on gonadotropin-releasing hormone (GnRH) neurons involved in pituitary-gonadal function. An immortalized GnRH-secreting GT1-7 cell line was used to evaluate the effects of 60% N2O exposure for 24 hours on pro-GnRH mRNA levels, KCl-stimulated GnRH levels, and certain signaling pathways. N2O exposure for 24 hours decreased pro-GnRH mRNA levels by approximately 80% without affecting cell viability or intracellular GnRH levels. The ability of KCl to release GnRH stores was also significantly reduced. Western blot analyses of ERK1/2, and p38 phosphorylation and IkappaB did not indicate any change in phosphorylation, although p63 tyrosine phosphorylation was increased after short-term N2O exposure. Levels of c-fos, a nuclear transcription factor, were not changed by N2O exposure. These results indicate that N2O significantly decreases evoked release of GnRH as well as GnRH mRNA levels either by decreased synthesis or by mRNA stability. These results may be important in understanding adverse effects of N2O on female workers in dental practice where the gas is not scavenged.

Analysis of Variance↗

PubMed2002

Identification of a 47-kb DNA fragment containing Xa4, a locus for bacterial blight resistance in rice.

Bacterial blight caused by Xanthomonas oryzae pv oryzae is a devastating disease in rice worldwide. The resistance gene Xa4 has been widely used in breeding programs and played an important role in protecting rice from this disease. Using 642 highly susceptible individuals and a random sample of 255 individuals from an F(2) population developed from a cross between IRBB4 and IR24, the Xa4 gene was genetically mapped to a region less than 1 cM. A contig map was constructed for the Xa4 region consisting of six non-redundant bacterial artificial chromosome (BAC) clones and spanning approximately 500 kb in length. Analysis of recombination events in the Xa4 region located the gene locus to one BAC, 3H8. Assay of the recombinants using the subclones of 3H8 in combination with sequence analysis further narrowed the Xa4 locus down to a 47-kb fragment.

Chromosome Mapping↗

PubMed2002

Molecular dissection of the genetic relationships of source, sink and transport tissue with yield traits in rice.

Source, sink, and translocation capacity of assimilates play important roles during the formation of grain yield. The present study was conducted to characterize the genetic bases of traits representing source, sink and transport tissue, and their relationships with yield traits in rice, by analyzing QTLs for these traits and various ratios among them. The genetic materials were a recombinant inbred population derived from a cross between two indica cultivars Zhenshan 97 and Minghui 63, the parents of the most-widely grown hybrid rice in China. Using a linkage map that covers a total of 1,796 cM based on 221 molecular marker loci, a total of 81 QTLs were identified for the 15 traits studied (three leaf areas as the source, total spikelets per panicle as the sink, the number of large vascular bundles in the stem as transport tissue, three source to sink ratios, three transport tissue to source ratios, one transport tissue to sink ratio and three yield traits). The amount of variation explained by individual QTLs ranged from 1.12% to 24.14%. Five QTLs were identified to show interaction effects with the environment, which explained from 3.19% to 9.15% of the variation. The results showed that close linkage or pleiotropy is the genetic basis for the correlations of grain yield traits with source, sink, transport tissue and the various ratios among them. Of the 25 QTLs identified for source-sink-transport tissue trait, and 43 for various ratios, 8 and 22 QTLs, respectively, were mapped to the similar genomic blocks harboring QTLs for yield traits, especially for grain weight. Co-location of QTLs for yield traits with those for ratios among source, sink and transport tissue may provide a genetic explanation for the physiological expression of yield traits, and also suggest that improvement in ratios among source, sink and transport tissue may result in improvement in yield potential.

Chimera↗

PubMed2002

Simultaneous improvement for four quality traits of Zhenshan 97, an elite parent of hybrid rice, by molecular marker-assisted selection.

"Zhenshan 97" is the female parent of a number of widely used hybrids for rice production in China. However, this line is of poor quality because of a high amylose content (AC), a hard gel consistency (GC) and a low gelatinization temperature (GT), together with a chalky endosperm. It had been determined that the three traits for cooking and eating quality, AC, GC and GT, are controlled by the Waxy locus and/or the tightly linked genomic region. In this study we improved the eating and cooking quality of Zhenshan 97 by introgressing the Waxy gene region from Minghui 63 (wx-MH), a restorer line, that has medium AC, soft GC and high GT. The wx-MH fragment was transferred to Zhenshan 97B by three backcrosses and one selfing, then from Zhenshan 97B to Zhenshan 97A by a cross and a backcross. Molecular marker-assisted selection was applied in the series to select for individuals carrying wx-MH, to identify recombination between the Waxy and flanking markers, and also to recover the genetic background of the recurrent parent. According to the marker genotypes, the improved versions of Zhenshan 97B and Zhenshan 97A, or Zhenshan 97B(wx-MH) and Zhenshan 97A(wx-MH), were the same as the originals except for the Waxy region of less than 6.1 cM in length. The selected lines and their hybrids with Minghui 63, or Shanyou 63(wx-MH), showed a reduced AC and an increased GC and GT, coupled with a reduced grain opacity. Field examinations of agronomic performance revealed that Zhenshan 97B(wx-MH) and Shanyou 63(wx-MH) were essentially the same as the originals except for a significant decrease in grain weight. The simultaneous improvement of AC, GA, GT and opacity, indicated that the Waxy region had major effects on the four quality traits. The improved versions of Zhenshan 97 A and B should be immediately useful in hybrid rice production.

Amylose↗

PubMed2002

Correct identification of polychlorinated biphenyls in temperature-programmed GC with ECD detection.

A method has been developed for peak identification of PCBs in GC with ECD detection under different temperature programs and isothermal conditions on two commonly used columns (DB-5 and DB-1701). This was achieved by means of accurate calibration of retention times based on the concept of the relative retention index P (i) and retention times of the selected PCB internal standards. The P (i) was calculated from the predicted retention times with the database of the retention parameters (A, B) and the migration equations. Through comparison of the calibrated and experimental retention times of PCBs in technical samples, it was shown that the developed method was effective for correct PCB comprehensive, quantitative, congener-specific (CQCS) analyses.

Journal Article↗

PubMed2002

Computer-assisted automatic peak recognition and result evaluation for analysis of chlorinated hydrocarbons in environmental samples.

A data manipulation method has been developed for automatic peak recognition and result evaluation in the analysis of organic chlorinated hydrocarbons with dual-column gas chromatography. Based on the retention times of two internal standards, pentachlorotoluene and decachlorobiphenyl, the retention times of chlorinated hydrocarbons can be calibrated automatically and accurately. It is very convenient to identify the peaks by comparing the retention times of samples with the calibrated retention times calculated from the relative retention indices of standards. Meanwhile, with a suggested two-step evaluation method the evaluation coefficients and the suitable quantitative results of each component can be automatically achieved for practical samples in an analytical system using two columns with different polarities and two internal standards.

Automation↗

PubMed2002

Molecular mechanisms of nickel carcinogenesis.

Humans are exposed to carcinogenic nickel (Ni) compounds both occupationally and environmentally. In this paper, molecular mechanisms of nickel carcinogenesis are considered from the point-of-view of the uptake of nickel sulfide particles in cells, their dissolution and their effects on heterochromatin. Molecular mechanisms by which nickel induces gene silencing, DNA hypermethylation and inhibition of histone acetylation, will be discussed.

Acetylation↗

PubMed2002

A study on the friction of a self-correction ultrasonic stepping motor.

An experiment has been carried out to investigate the self-correction function of a self-correction ultrasonic stepping motor. When a slider (rotor) is placed on a vibrating beam (stator), it will stay at a stable equilibrium position. If the slider is slightly moved off the equilibrium position, a restoring force will urge the slider back towards its equilibrium position. The experimental result shows that the position of the maximum restoring force on the slider differs from that predicted by using the linear theory. Study found that when a quadratic form is assumed for the dynamic friction coefficient, the theoretical and experimental results are in good agreement.

Journal Article↗

PubMed2002

Coronary artery disease and dyslipidemia within Europe: genetic variants in lipid transport gene loci in German subjects with premature coronary artery disease.

Fifteen polymorphisms in six lipid transport genes were studied in a German population for relationships with dyslipidemia and coronary artery disease (CAD), to investigate a possible genetic basis for the marked differences in mortality rates from coronary heart disease within Europe. In other populations these polymorphisms have all been associated with CAD or with phenotypes known to predispose to CAD. The apoAI PstI polymorphism (P<0.005) and the lipoprotein lipase Ser(447)-Ter mutation (P<0.005) were associated with plasma triglyceride concentrations. Additionally, the apoAI PstI polymorphism (P<0.05), the apoB XbaI polymorphism (P<0.05) and apoE phenotypes (P<0.05) were associated with plasma cholesterol concentrations. However, none of the allele frequencies of the polymorphisms studied were related to the presence, or absence, of coronary artery disease. Associations between five polymorphisms representing four lipid transport gene loci and dyslipidemia were demonstrated in this German population. It is possible that predisposition to dyslipidemia in Germany involves a particular selection of polymorphic loci, which are different from those identified in other European countries.

Adult↗

PubMed2002

Bipedal stance exercise and prostaglandin E2 (PGE2) and its synergistic effect in increasing bone mass and in lowering the PGE2 dose required to prevent ovariectomized-induced cancellous bone loss in aged rats.

Previous reports have shown that bone loss was partially prevented by bipedal stance "exercise" following ovariectomy (ovx), and it was well documented that prostaglandin E2 (PGE(2)) had an anabolic effect on the rat skeleton. The aim of this study was to determine whether lower doses of PGE(2) could prevent ovx-induced cancellous bone loss with the combination of bipedal stance exercise. Seventy-eight 10-month-old female Sprague-Dawley rats were either ovariectomized or sham-operated on day 0 and then treated with PGE(2) (0, 0.3, or 1 mg/kg per day) and/or housed in normal height cages (NC, 28 cm) or raised cages (RC, 33 cm) for 8 weeks. Bone histomorphometry was performed on the double-fluorescent-labeled proximal tibial metaphysis. In sham rats, 1 mg/kg PGE(2) + RC had synergistic effects in increasing trabecular bone area, width, and number by stimulating mineral apposition rate and bone formation rate. As expected, ovx induced cancellous bone loss, accompanied by elevated activation frequency. Without RC, PGE(2) monotherapy prevented ovx-induced bone loss at the 1 mg/kg per day dose, whereas this prevention effect was observed at the 0.3 mg/kg per day dose when combined with RC. Similar to their effects in sham rats, PGE(2) and RC had synergistic effects in augmenting cancellous bone mass and architecture and maintaining the elevated bone formation but depressing bone resorption and activation frequency. We conclude that bipedal stance exercise lowers the PGE(2) dose required to prevent ovx-induced cancellous bone loss in the proximal tibial metaphysis in aged rats.

Animals↗