Biomedical subjects
Publications and source records attributed to Peng Wang.
An ionic liquid polymer gel containing 1-methyl-3-propylimidazolium iodide (MPII) and poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) has been employed as quasi-solid-state electrolyte in dye-sensitized nanocrystalline TiO2 solar cells with an overall conversion efficiency of 5.3% at AM 1.5 illumination.
We have discovered potent and selective xanthine PDE5 inhibitors. Compound 25 (PDE5 IC(50)=0.6 nM, PDE6/PDE5=101) demonstrated similar functional efficacy and PK profile to Sildenafil (PDE5 IC(50)=3.5 nM, PDE6/PDE5=7).
Among a collection of 74 aprt mutations induced by treatment of plateau phase Chinese hamster ovary CHO cells with the radiomimetic DNA double-strand cleaving agent neocarzinostatin, nine were large-scale rearrangements. Molecular analysis indicated that all nine were highly conservative, non-homologous reciprocal exchanges, most of which were intrachromosomal as determined by fluorescence in situ hybridization. All but one of the parental sequences contained potential double-strand cleavage sites positioned such that the observed rearrangements could be explained by drug-induced double-strand breakage followed by trimming, templated patching and ligation of the exchanged ends. Predicted non-complementary 3' overhangs were often preserved in the newly formed junctions, suggesting alignment-based fill-in of the overhangs. Banding of metaphase spreads of these mutants, and of a number of mutants induced by the functionally similar compound bleomycin, revealed that bleomycin-induced reciprocal exchange mutants had multiple additional chromosome alterations and considerable chromosomal heterogeneity within each mutant line. In contrast, neocarzinostatin-induced reciprocal exchange mutants, as well as bleomycin-induced base substitution and single base deletion mutants, retained stable pseudodiploid karyotypes similar to that of the parent line. Thus, some reciprocal exchanges arising from misjoining of double-strand breaks were associated with global chromosomal instability, while other ostensibly similar events were not.
Protein tyrosine phosphatases (PTPs) are a large family of enzymes that catalyze the hydrolytic removal of the phosphoryl group from phosphotyrosyl (pY) proteins. In this work, we have developed a novel combinatorial library method, termed "enzyme-catalyzed loss of isotope peak signal enhancement (ECLIPSE)", to determine the substrate specificity of PTPs. This method involves partial labeling of pY at a nonbridging phosphate oxygen atom with 50% (18)O ((16)O/(18)O = 1:1). A 361-member solution-phase peptide library with randomization at the -1 and -2 positions (relative to pY), RNNXXpYA-NH(2) (X = 19 alpha-amino acids except for Cys), was synthesized with the partially (18)O-labeled pY by the split-synthesis method. Each member of the resulting pY peptide library appeared as a doublet peak in the mass spectrum (m/z m and m + 2.0043). Limited treatment of the library with a PTP removed the mass-degenerate phosphoryl group from the most preferred substrates to generate products as singlet peaks, which were readily identified and sequenced by tandem mass spectrometry. Screening of the pY library against the catalytic domain of SHP-1 revealed that SHP-1 prefers an acidic residue at the -2 position, with aspartic acid being slightly better than glutamic acid. At the -1 position, SHP-1 also prefers an acidic residue, although a variety of other amino acids are also tolerated. On the other hand, positively charged residues at these positions render the corresponding peptides very poor substrates of SHP-1. Several selected peptides were individually synthesized and assayed against SHP-1, and the kinetic data confirmed the screening results. These results demonstrate that ECLIPSE is a viable method for studying the substrate specificity of PTPs.
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Methylene blue-intercalated alpha-zirconium phosphate (MBZrP) micro particles in deionized water were deposited onto the surface of graphite powder to prepare graphite powder-supported MBZrP, which was subsequently dispersed into methyltrimethoxysilane-derived gels to yield a conductive composite. The composite was used as electrode material to fabricate a surface-renewable, rigid, leak-free carbon ceramic composite electrode, bulk-modified with methylene blue (MB). In the configuration, alpha-zirconium phosphate was employed as a solid host for MB, which acted as a catalyst. Graphite powder ensured conductivity by percolation, the silicate provided a rigid porous backbone and the methyl groups endowed hydrophobicity and thus limited the wetting section of the modified electrode. Peak currents of the MBZrP-modified electrode were surface-confined at low scan rates but diffusion-controlled at high scan rates. Square-wave voltammetric study revealed that MBZrP immobilized in carbon ceramic matrix presented a two-electron, three-proton redox process in acidic aqueous solution with pH ranged from 0.44 to 2.94. In addition, the chemically modified electrode showed an electrocatalytic activity toward nitrite reduction at +0.15 V ( vs. Ag/AgCl) in acidic aqueous solution (pH=0.44). The linear range and detection limit are 1x10(-6)-4x10(-3) mol x L(-1) and 1.5x10(-7) mol x L(-1), respectively.
Outflows of trihalomethane formation potential (THMFPs) which was chosen as an index of the amount and reactivity with chlorine of THMs precursors from soils were studied with soil column experiment. The results indicated that factors influencing THMFP concentrations of leacheates were the physicochemical properties of soils, especially contents, composition and reactivities with chlorine of humic substances, the pH value of feed solution and cumulative leaching volume. The THMFP concentrations of leachates rose with increases in amounts of humic substances with high solubility as well as reactivity with chlorine. The effluents of soil samples contained the lowest THMFP concentrations under the feed solution of the lowest pH value (pH 3.0). THMFPs appeared to more easily flow out from soils with the feed solution of lower pH value, which was properly due to the increases in solubility of humic substances under the lower pH value conditions. In most cases, THMFP concentrations of leachates showed decline with the increase of cumulative leaching volumes of feed solution.
Poly(ethylene glycol) (PEG)-coupled polyaniline (PANI) film surfaces were prepared by incorporating the chlorinie end-capped methoxy PEG (mPEGCl) of molecular weight of about 2000 onto the emeraldine (EM) base form of PANI via N-alkylation. The microstructure and composition of the mPEG-coupled PANI (mPEG-c-PANI) surfaces were characterized by atomic force microscopy, contact angle measurement and X-ray photoelectron spectroscopy. The concentration of surface-coupled mPEG increased with the increase in concentration of the mPEGCl solution. The mPEG-c-PANI film surfaces exhibited enhanced ability to repel protein adsorption, with only an moderate reduction in their electrical conductivity. The mPEG-c-PANI surface with a high concentration of coupled mPEG also exhibited good resistance towards platelet adhesion.
B-cell chronic lymphocytic leukemia (CLL) is a clonal B cell malignancy of morphologically mature, functionally immature B cells. B-cell CLL cells are known to be resistant to killing by anticancer and other agents. This resistance is associated with alterations in apoptosis and cell cycle regulated genes. In our earlier studies, we have demonstrated that CLL cells have differential expression of genes that are associated with apoptosis and cell cycle regulation, including elevated expression of Bcl-2, DAD-1, Cyclin D3 and cyclin dependent kinase 4 inhibitor. Therefore, in this study, in an attempt to study the role of Cyclin D3 in the resistant behavior of CLL cells, Cyclin D3 was down regulated using antisense oligonucleotide (AS-ODN) in WSU-CLL, a human CLL cell line. The down regulation of Cyclin D3 was confirmed by RT-PCR and flow cytometry techniques. The Cyclin D3 expression down-regulated WSU-CLL cells were then tested for their susceptibility to fludarabine, a chemotherapeutic agent. Our results showed that the Cyclin D3 expression down-regulated WSU-CLL cells were more susceptible to fludarabine mediated killing. Following treatment with fludarabine, there was a significant increase in the number of cells undergoing apoptosis in Cyclin D3 expression down-regulated WSU-CLL cells as determined by Annexin-V assay, cell cycle analysis for DNA content, and cytomorphology. Thus, our results indicate Cyclin D3 down regulation increases the killing of WSU-CLL cells with fludarabine by increasing the number of cells undergoing apoptosis.
Based on the analysis of information flow through the Artificial Neural Network (ANN), a new screening rule of the molecular structure parameter in Quantitative Structure-Activity Relationship (QSAR) was presented by comparing of the values of connection weights and biases of the ANN model. The result showed that model quality and prediction ability of QSAR model, which was constructed by screening structural parameter with ANN, were better than by the method with MLR. The method established the foundation for further study in the mechanism research of the bio-toxicity of organic chemicals.
N-(3,5-Dichloro-1-oxido-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 351591) has been identified as a potent (IC(50) = 58 nM) and highly selective type 4 phosphodiesterase (PDE4) inhibitor with oral bioactivity in several animal models of lung inflammation. N-(3,5-Dichloro-4-pyridinyl)-8-methoxy-2-(trifluoromethyl)-5-quinoline carboxamide (SCH 365351), the only significant in vivo metabolite, is also a potent and highly selective PDE4 inhibitor (IC(50) = 20 nM). Both SCH 351591 and SCH 365351 inhibited cytokine production in human blood mononuclear cell preparations. Oral SCH 351591 significantly attenuated allergen-induced eosinophilia and airway hyperreactivity in allergic guinea pigs at doses as low as 1 mg/kg. In this model, oral SCH 365351 showed similar potency. When SCH 351591 was administered orally to allergic cynomolgus monkeys at 3 mg/kg, Ascaris suum-induced lung eosinophilia was blocked. Hyperventilation-induced bronchospasm in nonallergic guinea pigs, a model for exercise-induced asthma, was also suppressed significantly by oral SCH 351591 at 0.3 mg/kg. Cilomilast (SB 207499; Ariflo), a PDE4 inhibitor currently being developed for asthma and chronic obstructive pulmonary disease (COPD), was 10- to 30-fold less potent than SCH 351591 at inhibiting guinea pig lung eosinophilia and hyperventilation-induced bronchospasm. In a ferret model of emesis, maximum nonemetic oral doses of SCH 351591 and cilomilast were 5 and 1 mg/kg, respectively. Comparison of plasma levels at these nonemetic doses in ferrets to those at doses inhibiting hyperventilation-induced bronchospasm in guinea pigs gave a therapeutic ratio of 16 for SCH 351591 and 4 for cilomilast. Thus, SCH 351591 exhibits a promising preclinical profile as a treatment for asthma and COPD.
The recovery process of nitric acid, copper and nickel in deplating wastewater was developed by using the combined technique of distillation, solvent extraction and precipitation. The conditions of the separation of copper and nickel by solvent extraction using P507 in kerosene and stripping copper with H2SO4 were specially investigated and the optimal parameters were determined. The results of experiment indicated that the recovery ratio of nitric acid was 97.8%, and under the optimized conditions of extraction process, concentration of original effluence ranged in 15-20 mg/mL copper, 5-10 mg/mL nickel, pH 1-2, concentration of extractant was 35% (V/V), saponification degree was 60%, phase ratio was 1:1, reaction time was 2 min, temperature ranged in 20 degrees C-25 degrees C, the one stage extraction efficiency of copper was higher than 90%, the separation ratio of copper and nickel was up to 75; copper and nickel could be completely separated by a continuous countercurrent three-stage extraction. The nickel could be recovered from the water phase by precipitating with NaOH and the recovery ratio of nickel reached up to 99.9% by controlling pH in solution within 10-11. After these treatment, the effluent could meet the national standards of wastewater discharge.
Nearly 91% of organic pollutants in Hong Kong leachate could be effectively removed by the UASB (upflow anaerobic sludge blanket) process followed by the fenton coagulation. The COD (chemical oxygen demand) of leachate was lowered from an average of 5620 mg/L to 1910 mg/L after the UASB treatment at 37 degrees C, and was further lowered to 513 mg/L after fenton coagulation. The remaining refractory residues could be further removed by photochemical oxidation with the addition of H2O2. The BOD/COD ratio was greatly increased from 0.062 to 0.142, indicating the biodegradability of organic residues was improved. The photochemical oxidation for the fenton-coagulation supernatant was most effective at pH 3-4, with the addition of 800 mg/L of H2O2, and UV radiation time of 30 minutes. The final effluent contained only 148 mg/L of COD, 21 mg/L of BOD (biochemical oxygen demand) and 56 mg/L of TOC (total organic carbon).
OBJECTIVE: To evaluate the clinical value of application of emergency bedside ultrasound cardiogram (UCG) in cardiac intensive care unit. METHODS: We conducted a retrospective analysis of 116 cases who received examination with emergency bedside UCG within the period from April 2000 to March 2001. RESULTS: The positivity rate of examination with emergency bedside UCG was 100% among these patients. The diseases identified were as follows: acute myocardial infarction in 41 cases, angina pectoris in 16, ventricular aneurysm in 5, perforation of ventricular septum in 2, rheumatic valvular disease in 9, dilated cardiomyopathy in 9 and aortic dissecting aneurysm in 7. CONCLUSION: Emergency bedside UCG has important value in clinical diagnosis of cardiac emergencies.
OBJECTIVE: To explore the differential diagnosis of early repolarization syndrome (ERS) in patients with ST-segment elevation and its clinical significance. METHODS: Five patients with ESR were clinically observed and followed up after discharge from hospital. RESULTS: All the patients complained of chest distress or chest pain, accompanied by ST-segment elevation in the precordial electrocardiogram leads. CONCLUSION: ESR is often misdiagnosed as acute myocardial infarction, acute coronary syndrome, Brugada syndrome or other diseases that may involve elevated ST-segment, and careful examination of the ECGs, echocardiogram, troponin I and the patients' history of heart diseases may help differentiate ESR from these diseases.
OBJECTIVE: To understand the diagnosis and treatment of pulmonary cryptococcosis. METHODS: Patients diagnosed as having pulmonary cryptococcosis in the past 15 years were retrospectively studied. Their demographic data, respiratory symptoms, diagnostic methods, chest radiograph, immune state, antifungal therapy and follow-up results were analyzed. RESULTS: Thirty cases of cryptococcosis were diagnosed, of which 7 were diagnosed as having pulmonary cryptococcosis, one of them presented with concomitant meningitis. Of the 7 patients, 4 were male and 3 were female, with a median age of 41.8. All were HIV negative; one case was immunocompromised with a history of colon cancer and glucocorticoid therapy for 8 months, while others were immunocompetent. Three patients complained of low fever or cough and sputum, while 4 others presented no symptoms. The X-ray and chest CT showed unilateral or bilateral patches, nodules or cavities. The diagnosis was made by pathology and bacterial culture of sputum or bronchoalveolar lavage fluid. Amphotericin B plus flucytosine were initially given to 4 patients, all of them developed liver and renal abnormalities to some degree after therapy. Three patients were given fluconazole or itraconazole initially. All the 7 patients with pulmonary cryptococcosis responded favorably to antifungal therapy and the prognosis was good. CONCLUSIONS: Clinically pulmonary cryptococcosis was less common than cryptococcal meningitis. Pathology and cryptococcal culture were essential to the diagnosis. For immunocompetent patients with pulmonary cryptococcosis, the prognosis was good.
Nearly 97% of organic chemicals in Hong Kong leachate could be effectively removed by the UASB(upflow anaerobic sludge blanket) process followed by the fenton coagulation. The COD of leachate was lowered from an average of 12,900 mg/L to 1440 mg/L after the USAB treatment, and was further lowered to 394 mg/L after the fenton coagulation. The remaining refractory residues could be further removed by ozonation with the addition of H2O2. The ozonation for the supernatant of the fenton coagulation was most effective at pH 7-8, with the addition of 300 mg/L of H2O2, and 30 min of reaction. The final effluent contained only 85 mg/L of COD and 10 mg/L of BOD5. On the other hand, direct ozonation of UASB effluent lowered the COD to 905 mg/L and BOD5 to 103 mg/L. Ozonation improved the biodegradability of the organic residues, and also converted part of organic-N in the leachate into NH3-N and NO3(-)-N.
The elevated atmospheric CO2 can make effects on the ecosystem, these effects will be mediated by the soil fauna. In this paper, we firstly discussed the response of the soil nematodes to the elevated atmospheric CO2 in different soil pattern and in different ecosystems. Some evidences indicate that soil fauna of the detritus food webs appear to show positive, neutral or negative responses to the atmospheric CO2 enrichment across different studies. The research prospect in the future was put forward. This paper can help us understand some ecological processes of farmland ecosystems according to the effect of elevated CO2 on soil nematodes and provide the foundation for managing farmland ecosystems effectively.