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Biomedical subjects

Feng He

Publications and source records attributed to Feng He.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Nitrification and denitrification in the integrated vertical flow constructed wetlands].

Nitrification and denitrification in the different layers of the integrated vertical flow constructed wetlands (IVCW) are studied. The results show the constants rate of nitrification and denitrification in the strata of IVCW were 0.01 - 6.35microg x (gxd)-1 and 3.37 - 4.19microg x (gxd)-1 respectively. The most probable number (MPN) method are employed to determine the number and distribution of nitrifying and denitrifying bacteria in the strata of the system. The results show that the numbers of nitrifying and denitrifying bacteria were 7.5 x 10(3) - 1.1 x 10(5) MPN x g(-1) and 7.5 x 10(6) - 1.1 x 10 MPN x g(-1) respectively. The positive correlation between bacteria and their action was obvious (r = 0.9661, p < 0.001, r = 0.7722, p < 0.025). It is also observed that the number of nitrifying bacteria and nitrification rate was decreased along the direction of the water in the IVCW, while denitrifying bacteria and denitrification rate was increased. And there was the significant negative correlation between nitrification and denitrification rate(r = -0.9776, p < 0.001).

Biodegradation, Environmental↗
PubMed2005

[Temporal and spatial characteristics of substrate enzyme activities and bacteria physiological groups in constructed wetland].

Six enzymes and five bacteria physiological groups from the substrate (soil) of integrated vertical flowing constructed wetland are chosen to study temporal and spatial characteristics. The research results show that significant differences existed in each enzyme during different months (p < 0.05). The enzyme activities of cellulase, protease and phosphatase were significantly higher in June, September and December than those in March; The enzyme activity of beta-glucosidase in June was significantly higher than those in other months; While urease activities in both September and December were extremely significantly higher than those in March and in June (p < 0.01); But the dehydrogenase was different from the above-mentioned enzymes, which had higher enzyme activities in June and in December than in March and in September. Compared with the temporal characteristics, the spatial characteristics of all six enzymes show consistency: the enzyme activities in the down-flow chamber were significantly higher than those in the up-flow chamber (p < 0.05), and all of the enzyme activities in both chambers were relatively lower with the increasing depths of substrate layers. The numbers of bacteria physiological groups were at peak in June and September and their spatial characteristics were the same with enzyme activities.

Bacteria↗
PubMed2005

[Forms and bio-availabilities of exogenous arsenic in purple soils].

This study showed that after As was added into purple soils for 10 days, 50.2%-61.1% of it transformed into residual As, occupying 68%-86% in original soils. For acid purple soil, the As forms were Al-As > Fe-As> Ca-As; for neutral purple soil, they were Ca-As > Al-As > Ca-As > Fe-As > A-As, and for calcic purple soil, they were Ca-As > Al-As > Fe-As >A-As. It is suggested that NH4Cl could be used as common extractant for different soils, because it slightly affected original As forms in soils, and showed a highly significant correlation (P = 0.01) to plant absorption. From pluralistic regressive analysis of plant As content and each As form, Al-As and Fe-As were the main available forms in acid purple soil, but A-As and Ca-As were the most important fractions in neutral and calcic purple soils. The study also showed that H3BO3 could restrain the F interference in the operation of As speciation separations.

Arsenic↗
PubMed2005

[Effects of compositions of Mahuang decoction on chemotaxis and leukotriene production from neutrophils in rats].

OBJECTIVE: To explore the regularity of recipe composition by observing inhibitory effects of disassembled compositions of Mahuang decoction (MHD) on chemotaxis and leukotriene production from neutrophils in rats. METHOD: Neutrophil aggregation was induced by intraperitoneal injection of glycogen in rats. Intraperitoneal lavage fluid (PLF) was collected and neu-trophils were removed. Neutrophils were stimulated by calciumionophore A23187 in vitro to produce leukotriene B4. The concentrations of leukotriene B4 was measured by reversed-phase high performance liquid chromatography(HPLC), chemotatic chamber assay was used to investigate the regulative role of MHD on chenmotaxis of the neutrophils in response to LPS stimulation. RESULT: Disassembled compositions of MHD could inhibite chemotaxis and leukotriene production from neutrophils in rats. Inhibitory effects of MHD on mast cells were different. CONCLUSION: MHD has significantly inhibitory effects on chemotaxis and leukotriene production from neutrophils in rats. The original formula (MHD) works best. These results have confirmed the rationality and scientific level of MHD.

Animals↗
PubMed2005

[Experimental study on anti-inflammatory effects of mahuang decoction and its compositions].

OBJECTIVE: To explore the regularity of recipe composition by observing anti-inflammatory effects of Mahuang Decoction (MHD) and its compositions. METHODS: Neutrophil aggregation was induced by intraperitoneal injection of glycogen in rats. Intraperitoneal lavage fluid (PLF) was collected and neutrophils were removed. Neutrophils were stimulated by calciumionophore A23187 in vitro to produce leukotriene B4. The concentration of leukotriene B4 was measured by reversed-phase HPLC, anti-inflammatory effect was observed by the auricular edema with dimethylbenze. RESULT: MHD and its compositions could inhibit the auricular edema with dimethylbenze and leukotriene production from neutrophils in rats. Inhibitory effects of MHD compositions were different. CONCLUSION: MHD had significantly inhibitory effects on the auricular edema with dimethylbenze and leukotriene production from neutrophils in rats. The original formula (MHD) worked best. These result confirmed the rationality and scientific level of MHD.

Animals↗
PubMed2005

[Cloning and expression of P450 genes CYPA14 and CYPA16 from Candida tropicalis 1230].

Cytochrome P450 (CYP) as a monooxygenase catalyzes the limiting-rate reaction in the oxidation pathway of Candida tropicalis (C. tropicalis). Two members of P450 gene CYPA16 and CYPA14 were isolated from C. tropicalis 1230 by cassette PCR method, based on cloning of the P450 partial gene. They are tandemly arranged on the chromosome, encoding the gene products of 522 and 540 amino acid residues respectively. The deduced amino acid sequences of CYPA14 and CYPA16 are identical to those of CYP52A14 and CYP52A16 respectively,and highly similar to those of CYP52A2 and CYP52A1 from C. tropicalis ATCC 750 respectively. Simultaneously, CYPA14 and CYPA16 from several dicarboxylic-acid-producing strains were also cloned, and some site-mutations were found in their sequence. CYPA14 and CYPA16 were expressed in the Saccharomyces cerevisiae strain. It was shown that the recombinant P450 content of CYPA14 was lower than that of CYPA16, and part of them were denatured. Comparing to C. tropicalis 1230, no significant changes were observed in recombinant P450 contents of CYPA14 and CYPA16 from every dicarboxylic-acid-producing strain.

Amino Acid Sequence↗
PubMed2005

[Preparation of forsythiaside from Forsythia suspensa by high-performance liquid chromato- graphy].

OBJECTIVE: To prepare forsythiaside from Forsythia suspensa by high-performance liquid chromatography (HPLC). METHOD: A crude extract of Forsythia suspensa was prepared by water extraction and alcohol precipitation prior to polyamide column chromatography. Forsythiaside was prepared from the crude extract by RP-HPLC. RESULTS: Analysis with HPLC showed that the purity of the prepared forsythiaside reached 98%. CONCLUSION: HPLC is simple and effective for the preparation of forsythiaside from Forsythia suspensa.

Chromatography, High Pressure Liquid↗
PubMed2005

[Clinical value of ultrasound guided transperineal prostate biopsy in detecting prostate cancer].

OBJECTIVE: To report our experience of ultrasound guided transperineal 6-core prostate biopsy (UG6CPB) in the diagnosis of prostate cancer (PCa). METHODS: In a prospective study, we performed UG6CPB in 104 suspected PCa patients with tPSA more than 4 microg/L and analysed the positive rate and complications of the diagnostic approach. RESULTS: PCa was detected in 24 of the 104 patients (23%), with low grade Gleason 2 to 4 in 3 cases (12.5%), intermediate grade Gleason 5 to 7 in 15 (62.5%) and high grade Gleason 8 to 10 in the remaining 6 (25%). Complications included temporary hematuria in 5 patients (4.8%), mild postbiopsy perineal discomfort in 5 (4.8%) and fever in 4 (3.8%). TPSA > or =10 microg/L, fPSA > or = 2 microg/L, fPSA/tPSA < 0.16, PSAD > or = 0.2 and prostate volume < 40 ml were the significant influencing factors of biopsy positive rate (P < 0.05). CONCLUSION: UG6CPB is an exact and a safe way of detecting PCa.

Biopsy, Needle↗
PubMed2005

[Determination of amygdalin content in Semen Armeniacae Amarum by high-performance liquid chromatography with evaporative light-scattering detection].

High-performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD) was employed for determination of amygdalin content in Semen Armeniacae Amarum. The detection was performed with the column of Hypersil-ODS (4.6 mm x 250 mm, 5 microm) and column temperature of 25 degrees C. The mobile phase was methanol-water (70:30) with flow rate of 0.5 ml/min. Evaporative light-scattering detector was used and the drift tube temperature was set at 98 degrees Celsius with the gas flow rate of 3.2 L/min. A standard curve was generated, which was linear in the range of 1.0-15.1 microg for amygdalin content (r=0.999 9). The average recovery of amygdalin was 99.0% with RSD of 2.9% (n=5). Besides simplicity and rapidness, the method yields accurate and reproducible results and can therefore be used in the quality control of Semen Armeniacae Amarum.

Amygdalin↗
PubMed2005

[Effect on pharmacokinetics of pseudo-ephedrine in human plasma among herbs in Mahuang decoction].

OBJECTIVE: To develop a GC-MS method for the determination of pseudo-ephedrine in human plasma and study the mutative rules of the pharmacokinetic parameters of the pseudo-ephedrine in different compositions. METHOD: Orthogonal design was used to determine 8 compositions from Mahuang decoction (MHD). The healthy volunteers were divided into groups in random, each group including 8 men. After taking the medicine orally, vena blood would be taken out at different time. Determining pseudo-ephedrine in plasma and plotting the concentration-time curve, the pharmacokinetic parameters of each composition were calculated by WinNonlin 4.0.1. The statistical analysis of the pharmacokinetic parameters was proceeded by SPSS 10.0. RESULT: All concentration-time curves were adequately modeled by one compartment, first order absorption model, no lag time. Some parameters of pseudo-ephedrine showed significant variance (P < 0.05) in different compositions. The statistic results showed interactions between drugs in MHD (P < 0.05). CONCLUSION: The other herbs erds of MHD have some certain extent effects to the pharmacokinetic parameters of pseudo-ephedrine in the dominant drug.

Administration, Oral↗
PubMed2005

Intravitreal clearance of moxifloxacin.

PURPOSE: To study the clearance of a single dose of intravitreally injected moxifloxacin in rabbits. METHODS: Intravitreal injections of 200 microg/0.1 mL of moxifloxacin were performed in rabbits. Four eyes per time interval after injection (1, 6, 12, 24, 36 hours) and three eyes at 48 hours were enucleated, immediately frozen, and placed at -80 degrees C. Ocular dissection and isolation of frozen vitreous were performed. Antibiotic assays were performed with use of high-performance liquid chromatography. RESULTS: The concentration of intravitreal moxifloxacin showed an exponential decay with a half-life of 1.72 hours. The mean vitreous concentration was 120.49 +/- 49.23 microg/mL 1 hour after injection, which declined to 20.23 +/- 5.85 microg/mL at 6 hours and 1.06 +/- 0.81 microg/mL at 12 hours. The aqueous levels of moxifloxacin showed an exponential decay from 10 microg/mL at 1 hour after intravitreal injection to undetectable levels by 12 hours after injection. CONCLUSIONS: Moxifloxacin clearance from the vitreous is rapid and consistent with previous clearance studies of ciprofloxacin. Given that the injected dose corresponds to several times the minimum inhibitory concentration at which 90% of isolates are inhibited (MIC90) of organisms commonly involved in endophthalmitis, and that therapeutic levels are present up to 12 hours after injection, intravitreal moxifloxacin may have a role in the treatment of endophthalmitis.

Animals↗
PubMed2004

Multiplexed protein quantitation in Saccharomyces cerevisiae using amine-reactive isobaric tagging reagents.

We describe here a multiplexed protein quantitation strategy that provides relative and absolute measurements of proteins in complex mixtures. At the core of this methodology is a multiplexed set of isobaric reagents that yield amine-derivatized peptides. The derivatized peptides are indistinguishable in MS, but exhibit intense low-mass MS/MS signature ions that support quantitation. In this study, we have examined the global protein expression of a wild-type yeast strain and the isogenic upf1Delta and xrn1Delta mutant strains that are defective in the nonsense-mediated mRNA decay and the general 5' to 3' decay pathways, respectively. We also demonstrate the use of 4-fold multiplexing to enable relative protein measurements simultaneously with determination of absolute levels of a target protein using synthetic isobaric peptide standards. We find that inactivation of Upf1p and Xrn1p causes common as well as unique effects on protein expression.

Cations↗
PubMed2004

How a G protein binds a membrane.

Heterotrimeric G proteins interact with receptors and effectors at the membrane-cytoplasm interface. Structures of soluble forms have not revealed how they interact with membranes. We have used electron crystallography to determine the structure in ice of a helical array of the photoreceptor G protein, transducin, bound to the surface of a tubular lipid bilayer. The protein binds to the membrane with a very small area of contact, restricted to two points, between the surface of the protein and the surface of the lipids. Fitting the x-ray structure into the membrane-bound structure reveals one membrane contact near the lipidated Ggamma C terminus and Galpha N terminus, and another near the Galpha C terminus. The narrowness of the tethers to the lipid bilayer provides flexibility for the protein to adopt multiple orientations on the membrane, and leaves most of the G protein surface area available for protein-protein interactions.

Animals↗
PubMed2004

Depth of proteome issues: a yeast isotope-coded affinity tag reagent study.

As a test case for optimizing how to perform proteomics experiments, we chose a yeast model system in which the UPF1 gene, a protein involved in nonsense-mediated mRNA decay, was knocked out by homologous recombination. The results from five complete isotope-coded affinity tag (ICAT) experiments were combined, two using matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry (MS/MS) and three using electrospray MS/MS. We sought to assess the reproducibility of peptide identification and to develop an informatics structure that characterizes the identification process as well as possible, especially with regard to tenuous identifications. The cleavable form of the ICAT reagent system was used for quantification. Most proteins did not change significantly in expression as a consequence of the upf1 knockout. As expected, the Upf1 protein itself was down-regulated, and there were reproducible increases in expression of proteins involved in arginine biosynthesis. Initially, it seemed that about 10% of the proteins had changed in expression level, but after more thorough examination of the data it turned out that most of these apparent changes could be explained by artifacts of quantification caused by overlapping heavy/light pairs. About 700 proteins altogether were identified with high confidence and quantified. Many peptides with chemical modifications were identified, as well as peptides with noncanonical tryptic termini. Nearly all of these modified peptides corresponded to the most abundant yeast proteins, and some would otherwise have been attributed to "single hit" proteins at low confidence. To improve our confidence in the identifications, in MALDI experiments, the parent masses for the peptides were calibrated against nearby components. In addition, five novel parameters reflecting different aspects of identification were collected for each spectrum in addition to the Mascot score that was originally used. The interrelationship between these scoring parameters and confidence in protein identification is discussed.

Amino Acid Sequence↗
PubMed2004

Degradation kinetics and mechanisms of phenol in photo-Fenton process.

Phenol degradation in photochemically enhanced Fenton process was investigated in this work. UV-VIS spectra of phenol degradation showed the difference between photo-Fenton process and UV/H(2)O(2), which is a typical hydroxyl radical process. A possible pathway diagram for phenol degradation in photo-Fenton process was proposed, and a mathematical model for chemical oxygen demand (COD) removal was developed. Operating parameters such as dosage of H(2)O(2) and ferrous ions, pH, suitable carrier gas were found to impact the removal of COD significantly. The results and analysis of kinetic parameters calculated from the kinetic model showed that complex degradation of phenol was the main pathway for removal of COD; while hydroxyl radicals acted weakly in the photo-Fenton degradation of phenol.

Computer Simulation↗
PubMed2004

[Studies on clogging of the constructed wetland].

The parameters of substrate related to clogging, such as the grain size, the filtration rate and organic substance in the substrate, were investigated in the integrated vertical-flow constructed wetland (IVCW). The substrate of IVCW was collected by a specific sampling tube in situ and the infiltration experiment showed that the filtration rate of substrate increased with the depth of substrate and the minimum filtration rate existed 15-30 cm below the surface of substrate. The amount of organic substances in upper 15 cm layer of the substrate was limited and even less in deeper layer after fifty two-month running, and this revealed that IVCW was operating steadily and no clogging was observed. Considering the factors related to clogging, the strategy to prevent and recover the clogging phenomenon was put forward.

Ecosystem↗
PubMed2003

Enhancement of phototransduction g protein-effector interactions by phosphoinositides.

Light responses in photoreceptor cells are mediated by the action of the G protein transducin (G(t)) on the effector enzyme cGMP phosphodiesterase (PDE6) at the surface of disk membranes. The enzymatic components needed for phosphoinositide-based signaling are known to be present in rod cells, but it has remained uncertain what role phosphoinositides play in vertebrate phototransduction. Reconstitution of PDE6 and activated G(alphat), on the surface of large unilamellar vesicles containing d-myo-phosphatidylinositol-4,5-bisphosphate (PI(4,5)P(2)), stimulated PDE activity nearly 4-fold above the level observed with membranes containing no phosphoinositides, whereas G protein-independent activation by trypsin was unaffected by the presence of phosphoinositides. PDE activity was similarly stimulated by d-myo-phosphatidylinositol-3,4-bisphosphate and d-myo-phosphatidylinositol-4-phosphate (PI(4)P), but much less by d-myo-phosphatidylinositol-5-phosphate (PI(5)P) or d-myo-phosphatidylinositol-3,5-bisphosphate. Incubation of rod outer segment membranes with phosphoinositide-specific phospholipase C decreased G protein-stimulated activation of endogenous PDE6, but not trypsin-stimulated PDE activity. Binding experiments using phosphoinositide-containing vesicles revealed patterns of PDE6 binding and PDE6-enhanced G(alphat)-GTPgammaS binding, consistent with the activation profile PI(4,5)P(2) > PI(4)P > PI(5)P approximately control vesicles. These results suggest that enhancement of effector-G protein interactions represents a possible mechanism for modulation of phototransduction gain by changes in phosphoinositide levels, perhaps occurring in response to longterm changes in illumination or other environmental cues.

Animals↗