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Biomedical subjects

X Wang

Publications and source records attributed to X Wang.

At least 127 records · Page 7Linked to original sources
PubMed2005

Granulocytosis and increased adhesion molecules after resistive loading of the diaphragm.

Upregulation of endothelial cell adhesion molecules, followed by an influx of granulocytes and macrophages, can contribute to exertion-induced skeletal muscle injury. The purpose of this study was to quantify circulating leukocyte subsets, diaphragm injury and infiltrating leukocyte subsets, and surface expression of vascular cell adhesion molecule (VCAM)-1 and intracellular adhesion molecule (ICAM)-1 in the diaphragm after inspiratory resistive loading (IRL). Eight New Zealand white rabbits underwent 1.5 h of IRL and seven control rabbits underwent a sham procedure. Blood samples, taken at baseline and 2, 6, 12, 24, 48 and 72 h after the onset of IRL or sham, showed that band cell counts had increased at 6 h post-IRL. Point counting of haematoxylin and eosin-stained cross-sections, sampled at 72 h post-IRL, showed greater injury in diaphragms from IRL rabbits compared with controls. Immunohistochemical processing showed increased expression of ICAM-1 and VCAM-1, and higher granulocyte and macrophage counts in IRL diaphragms than control diaphragms. Macrophages were the predominant inflammatory cells. Increased intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression, and infiltration of granulocytes and macrophages may contribute to inspiratory resistive loading-induced diaphragm injury.

Airway Resistance↗
PubMed2005

The role of peritoneal dialysis in renal replacement therapy: an update on medical aspects.

In this brief review, we discuss various medical factors that are of importance for the role of peritoneal dialysis (PD) in renal replacement therapy (RRT), whereas the complex role of non medical factors will only be mentioned briefly. The aim of any RRT, including hemodialysis, PD and renal transplantation, is to normalize the volume and composition of the body fluids, to remove uremic toxins, and to improve clinical outcome. In the following, we will focus on adequacy, preservation of residual renal function, fluid balance, infections, nutrition, cardiovascular disease and systemic inflammation in PD as these factors are strong predictors of clinical outcome in end stage renal disease patients.

Humans↗
PubMed2005

Municipal wastewater treatment with pond-constructed wetland system: a case study.

The performance of a pond-constructed wetland system in the treatment of municipal wastewater in Kiaochow city was studied; and comparison with oxidation ponds system was conducted. In the post-constructed wetland, the removal of COD, TN and TP is 24%, 58.5% and 24.8% respectively. The treated effluent from the constructed wetland can meet the Chinese National Agricultural and Irrigation Standard. The comparison between pond-constructed wetland system and oxidation pond system shows that total nitrogen removal in a constructed wetland is better than that in an oxidation pond and the TP removal is inferior. A possible reason is the low dissolved oxygen concentration in the wetland. Constructed wetlands can restrain the growth of algae effectively, and can produce obvious ecological and economical benefits.

China↗
PubMed2005

New aristolochic acid, aristololactam and renal cytotoxic constituents from the stem and leaves of Aristolochia contorta.

Two novel phenanthrene derivatives, aristololactam IVa (1) and 9-hydroxy aristolochic acid I (2) were isolated from the stem and leaves of Anstolochia contorta Bunge, together with 17 known compounds (3-19). The structures of these compounds were determined by spectroscopic analysis. The phenanthrenes obtained were tested for cytotoxicity against renal proximal tubular epithelial cell line (HK-2). Aristololactam IVa and 7-methoxy aristololactam IV were found to have strong cytotoxic activity against HK-2 cells with a potency similar to or even stronger than those of aristolochic acid I and aristololactam I.

Aristolochia↗
PubMed2005

Fuzzy control of nitrogen removal in predenitrification process using ORP.

In order to meet increasingly stringent discharge standards, new applications and control strategies for the sustainable removal of nitrogen from wastewater have to be implemented. In the past years, numerous studies have been carried out dealing with the application of fuzzy logic to improve the control of the activated sludge process. In this paper, fuzzy control strategies of predenitrification systems are presented that could lead to better effluent quality and, in parallel, to a reduction of chemicals consumption. Extensive experimental investigations on lab scale plant studies have shown that there was excellent correlation between nitrate concentration and ORP value at the end of the anoxic zone. Results indicated that ORP could be used as an on-line fuzzy control parameter of nitrate recirculation and external carbon addition. The optimal value of ORP to control nitrate recirculation and external carbon addition was - 86 +/- 2 mV and - 90 +/- 2 mV, respectively. The results obtained with real wastewater also showed the good performance and stability of the fuzzy controllers independently from external disturbances. The integrated control structure of nitrate recirculation and external carbon addition in the predenitrification system is also presented.

Bioreactors↗
PubMed2004

Id-I stimulates cell proliferation through activation of EGFR in ovarian cancer cells.

Increased EGFR (epidermal growth factor receptor) expression has been reported in many types of human cancer and its levels are positively associated with advanced cancers. Recently, upregulation of Id-1 (inhibitor of differentiation or DNA binding) protein was found in over 70% of ovarian cancer samples and correlated with poor survival of ovarian cancer patients. However, the molecular mechanisms responsible for the role of Id-1 in ovarian cancer are not clear. The aim of this study was to investigate the effect of Id-1 on ovarian cancer proliferation and its association with the EGFR pathway. To achieve this, we transfected an Id-1 expression vector into three ovarian cancer cell lines and examined cell proliferation rate by flow cytometry and bromodeoxyuridine staining. We found that ectopic Id-1 expression led to increased cell proliferation demonstrated by increased BrdU incorporation rate and S-phase fraction. The Id-1-induced cell growth was associated with upregulation of EGFR at both transcriptional and protein levels. In contrast, inactivation of Id-1 through transfection of an Id-1 antisense vector resulted in downregulation of EGFR. Our results indicate that increased Id-1 in ovarian cancer cells may promote cancer cell proliferation through upregulation of EGFR. Our findings also implicate that Id-1 may be a potential target for the development of novel strategies in the treatment of ovarian cancer.

Blotting, Western↗
PubMed2004

Marijuana impairs growth in mid-gestation fetuses.

Marijuana (Cannabis sativa) is the most commonly used illicit drug by pregnant women, but information is limited about the effects of prenatal cannabis exposure on fetal development. The present study evaluated the influence of early maternal marijuana use on fetal growth. Women electing voluntary saline-induced abortions were recruited at a mid-gestational stage of pregnancy (weeks 17-22), and detailed drug use and medical histories were obtained. Toxicological assays (maternal urine and fetal meconium) were used in conjunction with the maternal report to assign groups. Subjects with documented cocaine and opiate use were excluded. Main developmental outcome variables were fetal weight, foot length, body length, and head circumference; ponderal index was also examined. Analyses were adjusted for maternal alcohol and cigarette use. Marijuana (n=44)- and nonmarijuana (n=95)-exposed fetuses had similar rates of growth with increased age. However, there was a 0.08-cm (95% CI -0.15 to -0.01) and 14.53-g (95% CI -28.21 to 0.86) significant reduction of foot length and body weight, respectively, for marijuana-exposed fetuses. Moreover, fetal foot length development was negatively correlated with the amount and frequency of marijuana use reported by the mothers. These findings provide evidence of a negative impact of prenatal marijuana exposure on the mid-gestational fetal growth even when adjusting for maternal use of other substances well known to impair fetal development.

Adult↗
PubMed2004

Retiming of picosecond pulses by a cascaded second-order nonlinear process in quasi-phase-matched LiNbO3 waveguides.

A new technique for reducing timing jitter by using a cascaded second-order nonlinear process in quasi-phase-matched (QPM) LiNbO3 waveguides is proposed. It was found that the timing jitter of a signal at QPM wavelength is not transferred to the converted pulses during cascading in a 30-mm-long LiNbO3 QPM waveguide. Timing-jitter transfer characteristics in QPM LiNbO3 waveguides are evaluated by calculation of pulse evolution, and retiming of 1.5-ps pulses in 10- and 30-mm-long waveguides is demonstrated experimentally.

Journal Article↗
PubMed2004

Transition from Mott insulator to superconductor in GaNb4Se8 and GaTa4Se8 under high pressure.

Electronic conduction in GaM4Se8 (M=Nb,Ta) compounds with the fcc GaMo4S8-type structure originates from hopping of localized unpaired electrons (S=1 / 2) among widely separated tetrahedral M4 metal clusters. We show that under pressure these systems transform from Mott insulators to a metallic and superconducting state with T(C)=2.9 and 5.8 K at 13 and 11.5 GPa for GaNb4Se8 and GaTa4Se8, respectively. The occurrence of superconductivity is shown to be connected with a pressure-induced decrease of the MSe6 octahedral distortion and simultaneous softening of the phonon associated with M-Se bonds.

Journal Article↗
PubMed2004

Observation by an air-shower array in Tibet of the multi-TeV cosmic-ray anisotropy due to terrestrial orbital motion around the Sun.

We report on the solar diurnal variation of the galactic cosmic-ray intensity observed by the Tibet III air shower array during the period from 1999 to 2003. In the higher-energy event samples (12 and 6.2 TeV), the variations are fairly consistent with the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun, while the variation in the lower-energy event sample (4.0 TeV) is inconsistent with this anisotropy. This suggests an additional anisotropy superposed at the multi-TeV energies, e.g., the solar modulation effect. This is the highest-precision measurement of the Compton-Getting anisotropy ever made.

Journal Article↗
PubMed2004

Dynamic cardiorespiratory interaction during head-up tilt-mediated presyncope.

In 28 healthy adults, we compared the dynamic interaction between respiration and cerebral autoregulation in 2 groups of subjects: those who did and did not develop presyncopal symptoms during 70 degrees passive head-up tilt (HUT), i.e., nonpresyncopal (23 subjects) and presyncopal (5 subjects). Airflow, CO2, cerebral blood flow velocity (CBF), ECG, and blood pressure (BP) were recorded. To determine whether influences of mean BP (MBP) and systolic SP (SBP) on CBF were altered in presyncopal subjects, coherencies and transfer functions between these variables and mean and peak CBF (CBFm and CBFp) were estimated. To determine the influence of end-tidal CO2 (ETco2) on CBF, the relative CO2 reactivity (%change in CBFm per mmHg change in ETco2) was calculated. We found that in presyncopal subjects before symptoms during HUT, coherence between SBP and CBFp was higher (P=0.02) and gains of transfer functions between BP (MBP and SBP) and CBFm were larger (MBP, P=0.01; SBP, P=0.01) in the respiratory frequency region. In the last 3 min before presyncope, presyncopals had a reduced relative CO2 reactivity (P=0.005), likely a consequence of the larger decrease in ETco2. We hypothesize that the CO2-mediated increase in resistance attenuates autoregulation such that the relationship between systemic and cerebral hemodynamics is enhanced. Our results suggest that an altered cardiorespiratory interaction involving cerebral hemodynamics may contribute in the cascade of events during tilt that culminate in unexplained syncope.

Adult↗
PubMed2004

The steroid receptor RNA activator is the first functional RNA encoding a protein.

The steroid receptor RNA activator (SRA) has previously been characterized as belonging to the growing family of functional non-coding RNAs. However, we recently reported the Western blot detection of a putative endogenous SRA protein (SRAP) in breast cancer cells. Herein, we successfully suppressed the expression of this protein through specific RNA interference assay, unequivocally confirming its existence. Moreover, using database searches and Western blot analysis, we also showed that SRAP is highly conserved among chordata. Overall, our results suggest that SRA is the first example of a new class of functional RNAs also able to encode a protein.

Amino Acid Sequence↗
PubMed2004

Tissue transglutaminase catalyzes the formation of alpha-synuclein crosslinks in Parkinson's disease.

In Parkinson's disease (PD), conformational changes in the alpha-synuclein monomer precede the formation of Lewy bodies. We examined postmortem PD and undiseased (control) substantia nigra for evidence of pathological crosslinking of alpha-synuclein by tissue transglutaminase (tTG) using immunohistochemistry, immunoprecipitation, and Western blot. Consistent with previous reports, we found that both tTG and its substrate-characteristic N(epsilon)-(gamma-glutamyl)-lysine crosslink are increased in PD nigral dopamine neurons. Furthermore, both the tTG protein and its substrate crosslink coprecipitated with alpha-synuclein in extracts of PD substantia nigra. Unexpectedly, the isodipeptide crosslink was detected in the alpha-synuclein monomer as well as in higher molecular mass oligomers of alpha-synuclein. Although the intramolecularly crosslinked alpha-synuclein monomer was present in control tissue, it was highly enriched in PD substantia nigra. Conversely, significantly less uncrosslinked alpha-synuclein remained in the postimmunoprecipitate lysate of PD tissue than in control. Crosslinked alpha-synuclein, formed at the expense of the total alpha-synuclein monomer, correlated with disease progression. These results demonstrate that much of the alpha-synuclein monomer in PD nigra is crosslinked by tTG and thus may be functionally impaired. This modification appears to be an early step in PD pathogenesis, preceding the aggregation of alpha-synuclein in Lewy bodies.

Adult↗
PubMed2004

The Janus face of inflammation in ischemic brain injury.

Brain ischemia elicits an intense inflammatory reaction as evidenced by endogenous activation of microglia and infiltration of leukocytes from the systemic circulation into the brain. A key issue regarding the well-described inflammation in brain injury is whether this reaction is of salutary or detrimental nature in the short and longterm post ischemia. In this brief review, evidence in support for the possible beneficial as well as detrimental role of inflammatory cells and mediators in ischemic brain injury is highlighted. We offer the opinion that both benefits and adverse effects of the inflammatory reaction at large depent on the levels of a specific mediator, the temporal relationships to the injury, the context in which the mediator operates and the spatial relationships to the injury.

Animals↗
PubMed2004

Hemoglobin A1c levels in non-diabetic patients with end-stage renal disease (ESRD) receiving hemodialysis.

Hemoglobin A1c (HbA1c) level represents an established tool to monitor glycemic control in diabetic patients, but the previous commonly used tests of HbA1c in patients with end-stage renal disease (ESRD) may not be reliable because of the presence of anemia, assay interference from uremia, and decreased red blood cell (RBC) life span. HbA1c level measured by turbidimetric immunoassay method is not affected by the above factors. We enrolled 40 non-diabetic ESRD patients receiving hemodialysis and 55 non-diabetic patients without ESRD for this study. HbA1c was analyzed by turbidimetric immunoassays with Synchron CX system. We found that the average HbA1c level in non-diabetic ESRD patients receiving hemodialysis was 5.99% and in the control group was 5.45% (p<0.05). There was no significant difference in fasting glucose levels and Hct % between the two groups (p>0.05). Our limited data indicate that HbA1c levels are elevated in nondiabetic ESRD patients receiving hemodialysis. We propose that the elevated HbA1c level may be due to the repetitive exposure of patients' RBCs to the high glucose level in dialysate (200 mg/dl) or may reflect true glucose intolerance in non-diabetic patients with ESRD.

Adult↗