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Xu Wang

Publications and source records attributed to Xu Wang.

139 records · Page 8Linked to original sources
PubMed2002

Effects of partial ischaemia and volume loading on myocardial efficiency and cardiac performance in dogs.

AIMS AND METHODS: To determine whether volume loading may be beneficial for the performance of ischaemic heart, myocardial ischaemia was created by partial occlusion of the left anterior descending coronary artery (LAD) to reduce the blood flow to 30 approximately 40% of basal level in 11 open chest anaesthetised dogs. Global left ventricular function as well as regional performance were studied under four different levels of volume loading, euvolemia (EUVO), hypervolemia (HYPER), normovolemia and hypovolemia. RESULTS: Left ventricular dP/dt(max) and cardiac output were decreased significantly during partial occlusion (3511.2+/-425.2 mmHg/s and 0.9+/-0.1 l/min) compared with pre-occlusion (4486.5+/-419.2 mmHg/s and 1.3+/-0.1 l/min) (P<0.05). Cardiac work was also lowered during partial occlusion (75.4+/-5.2 vs. 106.5+/-2.4 mmHgxl/min) (P<0.05). During volume loading, cardiac output and work were elevated (1.2+/-0.2 l/min and 94.0+/-5.4 mmHgxl/min) compared with EUVO (P<0.05). Local contractile dysfunction occurred in the LAD region after partial occlusion. There were no significant differences of dysfunction between any conditions of volume loading. Percentage shortening of the LAD region was decreased during partial occlusion (8.3+/-1.1 vs. 25.0+/-2.7%) and also was higher in HYPER (13.5+/-2.6%) than that in EUVO (P<0.05). Partial occlusion and different conditions of volume loading did not significantly change the force and local work in the LAD region. Myocardial O(2) consumption (MVO(2)) in LAD region was decreased during partial occlusion with different levels of volume loading (P<0.05). Local myocardial efficiency (work/MVO(2)) was increased during partial occlusion compared with pre-occlusion (941.3+/-56.2 vs. 551.0+/-65.5 gxmm/ml O(2)/min/100 g, P<0.05) and was also higher in HYPER (1208.6+/-48.4 gxmm/ml O(2)/min/100 g) than that in EUVO (P<0.05). Local systolic work was decreased during partial occlusion compared with pre-occlusion (9.5+/-1.5 vs. 14.2+/-1.3 gxmm/beat), whereas local myocardial systolic mechanical efficiency was increased (496.3+/-45.7 vs. 667.2+/-39.8 gxmm/ml O(2)/min/100 g). There were no significant changes of local systolic work and local systolic myocardial efficiency between different volume loading, although they tend to be elevated with increasing volume loading. CONCLUSION: Increase of blood volume by 15% improved the impaired global performance caused by partial occlusion of the LAD in open-chest dogs. This improvement was not accompanied by further dysfunction or increased MVO(2) of ischaemic myocardium, and therefore might be beneficial without causing further damage to the insulted myocytes.

Analysis of Variance↗
PubMed2002

A non-peptide substance P antagonist down-regulates SP mRNA expression in human mononuclear phagocytes.

Substance P (SP), a potent modulator of neuroimmunoregulation, exerts its activity by binding to the neurokinin-1 receptor (NK-1R). The SP-NK-1R interaction is important in inflammation and viral infections, including HIV infection of human immune cells. We recently demonstrated that SP modulates HIV replication and that a non-peptide SP antagonist CP-96,345 inhibits HIV replication in human monocyte-derived macrophages (MDM) by affecting the SP-NK-1R interaction. In order to examine the effect of the SP antagonist on SP mRNA expression, MDM was incubated with or without CP-96,345 in the presence or absence of HIV infection. SP mRNA expression in these cells was then determined by real-time PCR technology. The effect of CP-96,345 on chemokine gene expression was also investigated by using a cDNA array assay. CP-96,345 down-regulated SP mRNA expression and antagonized exogenous SP-enhanced SP expression at the mRNA level, suggesting that SP autocrine regulation was interrupted by CP-96,345. CP-96,345 inhibited HIV replication in MDM, associated with down-regulated SP mRNA expression in comparison to HIV infection controls. In parallel with down-regulated SP and CCR5 mRNA expression, cDNA array assays indicated that CP-96,345 treatment also inhibited IL-8 gene expression, while enhancing expression of fractalkine and monocyte chemotactic protein-3 (MCP-3). Since SP plays an important role in inflammation and viral infections, these studies may have potential applications for therapeutic intervention of inflammation and viral infection of immune cells.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Alcohol potentiates HIV-1 infection of human blood mononuclear phagocytes.

BACKGROUND: Acute and chronic alcohol abuse impairs various functions of the immune system and thus has been implicated as a cofactor in HIV infection. The mechanisms by which alcohol affects the function of human immune cells that are the targets for HIV are unknown. METHODS: Human blood monocyte-derived macrophages (MDM) were incubated with or without alcohol (10-40 mM) for 24 hr and then infected with HIV for 24 hr. Culture supernatants were harvested for HIV reverse transcription assay. HIV entry receptor (CCR5, CD4, and CXCR4) expression was determined by reverse transcription-polymerase chain reaction and flow cytometry assays. Beta-chemokines were analyzed using enzyme-linked immunosorbent assay. Different HIV strains (Bal, SF-162, 89.6, and UG024) were used for infection experiments. In addition, ADA (macrophage-tropic strain) and murine leukemia virus envelope-pseudotyped HIV infection was carried out. RESULTS: Although alcohol had little effect on HIV T-lymphocyte-tropic strain infection, it significantly enhanced HIV R5 strain infection in MDM. The enhancing effect of alcohol on the HIV R5 strain was further evidenced by the observation that the R5 (ADA) strain envelope-pseudotyped HIV infection is markedly increased by alcohol, whereas murine leukemia virus envelope-pseudotyped HIV infection was not affected. Alcohol significantly up-regulated CCR5 receptor expression and inhibited the endogenous production of beta-chemokines by MDM. CONCLUSION: Alcohol, through the down-regulation of beta-chemokine production and the up-regulation of CCR5 receptor expression, enhances HIV R5 strain infection of MDM and may have an important role as a cofactor in the progression of HIV disease.

Cells, Cultured↗
PubMed2002

Morphine enhances HIV infection of human blood mononuclear phagocytes through modulation of beta-chemokines and CCR5 receptor.

BACKGROUND: Injection drug use remains a significant risk for acquiring HIV infection. The mechanisms by which morphine enhances HIV infection of human immune cells are largely unknown. OBJECTIVE: In this study, we sought to determine the possible mechanisms by which morphine upregulates HIV infection of human blood monocyte-derived macrophages (MDM). METHODS: In this study, MDM were infected with the R5, X4, and R5X4 HIV strains. HIV replication was determined by performing reverse transcriptase activity assays. HIV receptors were determined by performing reverse transcriptase polymerase chain reactions and flow cytometry assays. beta-chemokines were analyzed by performing enzyme-linked immunosorbent assays. In addition, HIV R5 strain and murine leukemia virus envelope-pseudotyped HIV infection was performed to determine whether morphine affects HIV infection of macrophages at entry level. RESULTS: Morphine significantly enhanced HIV R5 strain infection of MDM but had little effect on X4 strain infection. The macrophage-tropic R5 strain envelope-pseudotyped HIV infection was markedly increased by morphine, whereas murine leukemia virus envelope-pseudotyped HIV infection was not significantly affected. Furthermore, morphine significantly upregulated CCR5 receptor expression and inhibited the endogenous production of beta-chemokines in MDM. The opioid receptor antagonist naltrexone blocked the effects of morphine on the production of beta-chemokines. CONCLUSION: Opiates enhance HIV R5 strain infection of macrophages through the downregulation of beta-chemokine production and upregulation of CCR5 receptor expression and may have an important role in HIV immunopathogenesis.

Chemokines, CC↗
PubMed2002

Estrogen modulation of eNOS activity and its association with caveolin-3 and calmodulin in rat hearts.

Previous studies have shown that estrogen modulation of endothelial nitric oxide (NO) synthase (eNOS) may confer protection against heart disease. Here, we demonstrate an association between reductions in baroreflex-mediated bradycardia and in cardiac NOS activity in ovariectomized (Ovx) rats compared with controls. The latter resulted, at least in part, from a reduction in cardiac eNOS protein. eNOS-derived NO and its biological effects are determined by the levels of eNOS protein and by eNOS catalytic activity; the latter is regulated partly through the dynamic interaction with an inhibitory protein (caveolin) and a stimulatory protein (calmodulin). The association of eNOS immunoprecipitated with caveolin-3 and calmodulin was examined. Caveolin-3 and calmodulin binding with eNOS was increased and decreased, respectively, in Ovx rats. 17 beta-Estradiol replacement restored, to within normal levels, the baroreflex-mediated bradycardic responses along with eNOS activity, eNOS expression, and the association of eNOS with caveolin-3 and calmodulin. Our findings may help to elucidate the molecular mechanism underlying the favorable effects of estrogen on cardiac responses to baroreflex activation.

Animals↗
PubMed2002

[Analysis on competition and coexistence patterns of Aneurolepidium chinense and its main companion species].

In this study, transects were set in areas where Aneurolepidium chinense and its companion species grew together. Competition and coexistence patterns of these species in the ecotone were analyzed using the following measures:frequency distribution, spatial pattern, and pattern intensity. Patterns of A. chinense and its main companion species were diverse. Aggregation was the tactics for A. chinense to defend the foreign species' invading or disperse itself. There existed competition and coexistence between A. chinense and its main companion species. A. chinense and Phragmite communis competed and coexisted through suppression. A. chinense and Kalimeris interifolia coexisted through competition. Hierochloe glabra and Puccinellia tenuiflora competed with A. chinense through clonal growth. Calamagrostis epigeios was suppressed by A. chinense.

China↗
PubMed2002

[Comparison of leaf tissue turnover for Leymus chinensis and Phragmites communis after grazing].

Leaf tissue turnover of Leymus chinensis and Phragmites communis after grazing was studied by application of theory and method of tissue turnover in this paper. The results showed that the number of living leaf of P. communis was larger than that of L. chinensis, but the length of living leaf of L. chinensis was larger than that of P. communis during the whole growth period. Both of the leaf appearance rate and the leaf elongation rate of L. chinensis and P. communis were largest at first, and then they decreased gradually. The rate of leaf wither and leaf senescence were in the converse trend. The leaf lifespan of P. communis was shorter than that of L. chinensis. The velocity of leaf tissue turnover of P. communis was faster than that of L. chinensis. There would be a great loss if the leaf tissue of L. chinensis were not used in time. The quality of grasslands could be improved by different utilization ways and periods.

Animals↗
PubMed2002

[Induction of non-disjunction of chromosome 8 by Tripterygium hypoglaucum (Lévl.) Hutch in mouse sperm].

Fluorescence in situ hybridization (FISH) was employed to detect non-disjunction of chromosome 8 during meiosis in young adult male mice after treated by Tripterygium hypoglaucum(Lévl.) Hutch(THH). The Kunming male mice were given THH(120 mg/kg, 240 mg/kg, 480 mg/kg) by abdominal cavity injection, and sacrificed 22 days sfter the treatment of THH. Epididymis sperm was used to make smear. FISH using bio-16-dUTP-labelled DNA probes specific for chromosome 8 was performed on epididymal sperm decondensed for 60 min each in 10 mmol/L DTT and 4 mmol/L LIS. The aneuploidy frequencies of chromosome 8 were significantly higher than the solvent control (P < 0.001) in both 240 mg/kg group and 480 mg/kg group. The aneuploidy frequencies were not significantly different between the sperm in 120 mg/kg group and the solvent control (P > 0.05). It is concluded that THH could induce non-disjunction of chromosome 8 in mouse sperm, and THH is a potential germinal aneugen in mammalian during the meiosis.

Aneuploidy↗
PubMed2002

[Detection of telomerase activity in bronchoscopic brush-off samples in patients with lung cancer].

BACKGROUND AND OBJECTIVE: Recent studies have shown that activation of telomerase plays an important role in carcinogenesis. However, there was few report on the level of telomerase activity in small samples from the patients with lung cancer. This study was designed to investigate the diagnostic significance of the detection of telomerase activity in bronchoscopic brush-off cells from the patients with lung cancer. METHODS: Telomeric repeat amplification protocol(TRAP)-based telomerase polymerase chain reaction(PCR)-enzyme-linked immunosorbent assay (ELISA) TRAP-PCR-silver staining were employed to detect telomerase activity in 56 samples of brushing cells from the patients with lung cancer and 10 samples with inflammation. RESULTS: The positive rate of telomerase activity in 56 biopsy samples of lung cancer group was significantly higher than that in inflammation group (P < 0.001). The sensitivity, specificity, and accuracy of detection of telomerase activity was 87.5%, 83.3%, and 86.3%, respectively. There was no significant difference in the positive rate of telomerase activity between central lung cancer and peripheral lung cancer. Positive rate of detection of telomerase activity in bronchoscopic brush-off cells was 46.4%. The positive rate of telomerase activity detected in TRAP-PCR-ELISA was higher than that detected in TRAP-silver staining, but the significant difference was not found. It was found that samples with low absorbing value detected in the quantified way would show weak positive with less ladder bands or vague ladder bands if detected in the latter way. CONCLUSION: The telomerase activity may be a good marker for diagnosis of lung cancer. Combined with cytologic measure, it is possible to raise the early diagnostic rate of lung cancer.

Adult↗
PubMed2001

Methadone enhances human immunodeficiency virus infection of human immune cells.

Opiate abuse has been postulated to be a cofactor in the immunopathogenesis of acquired immunodeficiency syndrome (AIDS). This study evaluated whether methadone, a drug widely prescribed for the treatment of drug abusers with opioid dependence, affects human immunodeficiency virus (HIV) infection of human immune cells. When added to human fetal microglia and blood monocyte-derived macrophage cultures, methadone significantly enhanced HIV infection of these cells. This enhancement was associated with the up-regulation of expression of CCR5, a primary coreceptor for macrophage-tropic HIV entry into macrophages. Most importantly, the addition of methadone to the cultures of latently infected peripheral blood mononuclear cells from HIV-infected patients enhanced viral activation and replication. Although the in vivo relevance of these findings remains to be determined, the data underscore the necessity of further studies to define the role of opioids, including methadone, in the immunopathogenesis of HIV infection and AIDS.

Adult↗
PubMed1999

Significance of runaway calcium homeostasis in cultured cardiomyocytes in development of hypoxia, burnt serum-induced injury.

OBJECTIVE: This study aimed at understanding of the role of calcium homeostasis in cardiomyocytes from hypoxia, burnt serum-induced injury. METHODS: Alterations in cytosolic free calcium concentration (Ca(i)), calcium influx and viability of the cardiomyocytes in vitro after hypoxia, burnt serum stimulus were observed. RESULTS: Ca(i) increased markedly, in the meantime, the cellular transmembrane calcium influx increased and the viability of the cells decreased significantly following hypoxia, burnt serum-induced injury. CONCLUSIONS: In our study cytosolic calcium ion was transported abnormally in the cardiomyocytes after burn, to result in Ca(i) increase and runaway calcium homeostasis, thus the normal cellular function was disturbed. This may be one of the important factors in the development of burn-induced cardiac injury.

Journal Article↗
PubMed1999

Neuronal and behavioral discrimination between upward and downward pulse interval modulation in cochlea implanted gerbils.

Speech coding strategies for cochlear implants commonly use amplitude modulations of constant high rate pulses to differentially stimulate separate frequency channels in the cochlea. Thereby, time domain information in the fine structure of speech sounds, especially on transients, is largely lost. In gerbils with a single electrode cochlear implant was explored, whether upward and downward interval modulation of pulse trains can carry discriminable information. This question was pursued with unit recordings in primary auditory cortex (AI) and with behavioral discrimination training in a shuttle box. Units in AI showed multiple differences in the dynamic responses to the two directions of interval modulation and notably ON-response dominated patterns with increasing intervals and OFF-response dominated patterns with decreasing intervals of stimulation. In accordance with these neuronal correlates gerbils learned to distinguish the directions of interval modulation within 3 days, but only with certain specifications.

Journal Article↗