Biomedical subjects

Yan Wu

Publications and source records attributed to Yan Wu.

At least 109 records · Page 6Linked to original sources

PubMed2004

OH radicals generated by DC corona discharge for improving the pulsed discharge desulfuration efficiency.

Positive DC corona discharge is formed with needle-plate electrode configuration, in which the water vapor is ejected though the needle points. The purpose is to increase the numbers of the water-based radicals, ionize the water molecule and improve the desulfuration efficiency of pulsed corona reactor. The water ions were determined by four stages molecular beam mass spectrometer and diagnose the water-based radicals by emission spectrograph. A conclusion on formation of ions and radicals with DC corona discharges can be drawn.

Electrodes↗

PubMed2004

Expression of CC chemokine ligand 20 and CC chemokine receptor 6 mRNA in patients with psoriasis vulgaris.

In order to explore the possible role of CC chemokine ligand 20 (CCL20) and its receptor CC chemokine receptor 6 (CCR6) in the pathogenesis of psoriasis, the expression levels of mRNA of them in psoriatic lesions were investigated. The skin biopsies were collected from skin lesions in 35 cases of psoriasis vulgaris and 18 normal controls. RT-PCR was used to semi-quantitatively analyze the mRNA expression of CCL20 and CCR6 in the psoriatic lesions and the normal skin tissues. The results showed that the mRNA of CCL20 and CCR6 was present in every specimen. The expression levels of CCL20 mRNA in skin lesions were 1.1397 +/- 0.0521, which were greatly higher than those in normal controls (0.8681 +/- 0.0308) (P<0.001). The expression levels of CCR6 mRNA in skin lesions were 1.1103 +/- 0.0538, significantly higher than in the controls (0.9131 +/- 0.0433, P<0.001). These findings indicate that up-regulated expression of CCL20 and CCR6 mRNA might be related to the pathogenesis of psoriasis.

Adolescent↗

PubMed2004

Guangsangons F-J, anti-oxidant and anti-inflammatory Diels-Alder type adducts, from Morus macroura Miq.

Five Diels-Alder type adducts, named guangsangons F, G, H, I, and J, along with two known compounds, mulberrofuran J and kuwanon J, were isolated from Morus macroura Miq. Their structures were determined by means of spectroscopic analyses and chemical methods. These compounds were regarded biogenetically as Diels-Alder type adducts of dehydroprenylphenols and chalcone derivatives, and (1)H NMR variable temperature experiments suggested that they all existed as an equilibrium mixture of conformational isomers in solution. Among the isolated new compounds, guangsangons H, I, and J displayed potent antioxidant activities and moderate anti-inflammatory activities.

Animals↗

PubMed2004

Alkaloids from the fungus Lactarius subplinthogalus.

A new alkaloid, namely laccarin A (1), along with four known alkaloids, laccarin (2), adenosine (3), indole-3-carboxaldehyde (4) and nicotinamide (5), was isolated from the fungus Lactarius subplinthogalus. The structure of laccarin A (1) was established mainly by spectroscopic methods.

Alkaloids↗

PubMed2004

Chemical constituents from Pseudolarix kaempferi.

A novel degraded triterpenoid isopseudolaritone A (1) and one new oligosaccharide, 1-O-isopropyl-6-O-[2-O-methyl-alpha-L-rhamnopyranosyl(1 --> 6)]-beta-D-glucopyranose (2), two new artefacts, 9-O-formacyl cedrusin (5) and 9,9'-O-diformacyl cedrusin (6), as well as 12 known phenolic Compounds (3-4, 7 16), were isolated from the root bark of Pseudolarix kaempferi. Their structures were elucidated mainly by spectroscopic methods.

Humans↗

PubMed2004

Effect of hydrodynamic environment on tablets dissolution rate.

The main objective of this research was to develop an experimental method to apply well-defined flow fields to solid dosage forms, to study the rate process underlying tablet dissolution, and to better understand the role of external hydrodynamic condition on mass transfer rate and film thickness during dissolution. Two drugs models, Theophylline (class 1) and Naproxen (class 2), were selected and formulated into conventional tablets containing 105 mg Theophylline or 300 mg Naproxen using the wet granulation method. Tablets were tested for dissolution using both the basket and paddle methods at different rotational speed of 25, 50, 75, and 100 rpm. In general, the paddle method gave higher dissolution rates than the basket method and as the velocity of rotation was increased, drug release was also increased. Six different paddles and a tablet holder were designed and used to test dissolution rate. The rate of dissolution was dependent on the tablet surface area exposed to the dissolution medium, and on the shape, diameter, and area of the paddles used. Theophylline tablets showed increased mass transfer rate and decreased film thickness as basket rotation speed was increased. At 25 rpm, the mass transfer coefficient was 0.684 x 10(-4) cm/sec and film thickness was 12.003 x 10(-2) cm; at 100 rpm, the mass transfer coefficient was 3.884 x 10(-4) cm/sec and film thickness was 2.114 x 10(-2) cm. Paddle values tested at the same speed showed higher mass transfer coefficient and lower film thickness for Theophylline and Naproxen tablets. P values obtained by modification of the Stokes-Einstein equation showed that diffusion is the rate-limiting step to drug release and not mass transfer. This study demonstrated that hydrodynamic condition, type of dissolution testing used, and design of the paddles have an effect on dissolution rate, mass transfer rate, and the film thickness underlying the dissolution process.

Chemistry, Pharmaceutical↗

PubMed2004

Vascular endothelial growth factor receptor-3 in hypoxia-induced vascular development.

Reduced tissue oxygen tension (hypoxia) is appreciated as an efficient stimulus for neovascularization. The effect of hypoxia on the very first stages of vascular development is, however, less well characterized. Here we show that hypoxic conditions (1% O2) potently stimulated formation of an extensive vascular network during a discrete stage of mouse embryonal stem cell differentiation. The morphological changes correlated with an expanding pool of endothelial cells and with activation of the vascular endothelial growth factor-d (Vegf-d) and Vegf receptor-3 genes. VEGF receptor-3 expression was confined to vascular endothelial cells and analysis of the lymphatic marker Prox-1 revealed no expansion of lymphatic endothelial cells. Administration of neutralizing antibodies against either VEGF receptor-3 or VEGF receptor-2 impaired vascular network formation, whereas neutralizing antibodies against VEGF receptor-1 potentiated development of immature vascular structures. In addition, sequestering of VEGF receptor-3 ligands reduced vascularization in a manner similar to neutralization of VEGF receptor-3. We conclude that hypoxia-driven vascular development requires the activity of VEGF receptor-3.

Animals↗

PubMed2004

A robust DSP integrator for accelerometer signals.

The need for an accepted method for determining position data from digital accelerometer readings with known frequency range is very important. The method of this paper uses spectral information and provides more stability and accuracy than classic methods for the DSP case. It even reduces to a classic method for the nonoscillatory case. Examples show the robustness of the method, overcoming the instability apparent with other integration methods.

Acceleration↗

PubMed2004

Fetal alcohol exposure alters neurosteroid levels in the developing rat brain.

Neurosteroids are modulators of neuronal function that may play important roles in brain maturation. We determined whether chronic prenatal ethanol exposure altered neurosteroid levels in the developing brain. Rat dams were exposed to: (i) a 5% ethanol-containing liquid diet that produces peak maternal blood alcohol levels near the legal intoxication limit (approximately 0.08 g/dL); (ii) an isocaloric liquid diet containing maltose-dextrin instead of ethanol with pair-feeding; (iii) rat chow ad libitum. Neurosteroid levels were assessed in offspring brains using radioimmunoassay or gas chromatography-mass spectrometry techniques. A prenatal ethanol exposure-induced increase in pregnenolone sulfate levels, but not dehydroepiandrosterone sulfate levels, was evident at the earliest time point studied (embryonic day 14). This effect lasted until post-natal day 5. Levels of other neurosteroids were assessed at embryonic day 20; pregnenolone levels, but not allopregnanolone levels, were elevated. Pregnenolone sulfate levels were not altered in the maternal brain. Neither pregnenolone nor pregnenolone sulfate levels were significantly altered in the fetal liver, placenta and maternal blood, indicating that the effect of ethanol is not secondary to accumulation of peripherally-produced steroids. Fetal ethanol exposure has been shown to decrease both cellular and behavioral responsiveness to neurosteroids, and our findings provide a plausible explanation for this effect.

Age Factors↗

PubMed2004

New Diels-Alder type adducts from Morus macroura and their anti-oxidant activities.

Fractionation of the ethanolic extract of the stem bark of Morus macroura resulted in the isolation of four new Diels-Alder type adducts, named guangsangons K--N (1, 2, 5, 6), together with two known compounds, mulberrofuran G (3) and K (4). Their structures were determined on the basis of spectroscopic analyses and chemical methods. Furthermore, by means of (1)H-NMR variable temperature experiments and the Cotton curves in the circular dichroism (CD) spectra, the stereochemistry of four new compounds was elucidated. The isolated new compounds showed good activity on anti-oxidant in vitro, with the inhibitory rates of MDA being from 91.8 to 100.0% at concentrations of 10(-5) mol/l.

Antioxidants↗

PubMed2004

[Effects of autologous hematopoietic stem cell transplantation on immune function in patient with systemic lupus erythematosus].

To investigate the effects of autologous hematopoietic stem cell transplantation (AHSCT) on immune index in patient with systemic lupus erythematosus (SLE), and evaluate its treatment outcome, the flow cytometry (FCM) and enzyme linked immunosorbent assay (ELISA) were used to detect the leukocyte differentiation antigen, sIL-2R, IL-6, C3, C4, autoantibodies, immunoglobulin for 33 case of SLE before transplantation and at 1, 3, 6, 12 months after transplantation. The results showed that the ratio of CD4(+), CD19(+) cell, the level of sIL-2R, IL-6 and the positive rate of autoantibodies were significantly lower, CD8(+), CD16(+)CD56(+) cell and C3, C4 were higher than those before transplantation. Out of the 33 patients, 26 achieved CR, 3 reached PR and 4 relapsed at 4 - 6 months after transplantation. It is concluded that the immune indexes of patients with SLE changed significantly following AHSCT. These immune indexes may be indications to predict the status of remission in patient with SLE.

Adolescent↗

PubMed2004

[Dynamics of biomass and stem volume of Picea asperata stands in artificial restoration process of subalpine coniferous forest].

The dynamics of aboveground biomass and stem volume in subalpine coniferous Picea asperata plantations with different stand ages in 70 years of artificial restoration process were studied by adopting the concept of space as a substitute for time. The results indicated that before 20 years of stand age, the biomass of spruce single tree grew quite slow, with that of the twigs and needles accounting for about 50%; after 20 years, it increased obviously, with 60% of biomass accumulated in stem; from 30 to 40 years, the increasing rate of biomass relatively slowed down, and maintained a rapid growth after 40 years. The biomass of spruce population showed a similar trend, though the period of relative slow-down of growth continued from 30 to 50 years. For the biomass of community as a whole, it presented a general continuous increase, but varied greatly for different layers. In shrub layer, the biomass rose rapidly at the early stage of plantation establishment and gradually decreased after 20 years, while that of the herbaceous plants reduced continuously and accounted less than 0.2% of the total biomass of community when the stand reached 70 years. Both the mean annual increment and the current annual increment of stem volume of spruce single tree went up with the increasing stand age, and more rapidly at the later stages. Similar changes were observed for the stock volume of the plantations, with the only difference that the current annual increment from 30 to 50 years was relatively reduced. Based on the data from stem analysis and growth ring measurement, regression models of stem volume with DBH and tree height of 70 years Picea asperata plantation were established.

Biomass↗

PubMed2004

[A biomechanical study on the morphological changing process of human bitemarks].

This is a biomechanical research in the morphological changing process of human bitemarks on the skin of dogs. The human bitemarks were made on the live and dead dogs by different tooth and occlusal force. The changing process of the bitemarks were recorded for a long time and its related morphological parameters were measured. Then multiple stepwise regression analysis was made to disclose the relationship of the shape of the bitemarks to occlusal force, time, and tooth area, tooth width and thickness. The mathematic relationship of the morphological changing process of the bitemark with occlusal force, time and tooth shape was established.

Animals↗

PubMed2004

[The effect of "huang lian jie du tang" active fraction on experimental cerebral ischemia].

OBJECTIVE: To study the protective effect of "Huang Lian Jie Du Tang" active fraction (HLJDTAF) on experimental cerebral ischemia. METHODS: Middle cerebral artery occlusion (MCAO) in rats was used to observe the protective effect of HLJDTAF on ischemia stroke. Common carotid artery occlusion (CCAO) rat was used to analyse the effect of HLJDTAF on blood brain barrier (BBB) permeability. Common carotid artery occlusion and reperfusion repeatedly (CCAORR) in mice were used to test effect of HLJDTAF on gasp time, brain exponential and water content of brain. RESULTS: HLJDTAF could improve the abnormal behavior of MCAO rats and decrease the infarction area (P < 0. 05, P < 0. 01). HLJDTAF could also significantly prolong the shorten gasp time of CCAORR mice, reduce the brain exponential and decrease the water content in brain (P < 0. 05, P < 0. 01). CONCLUSIONS: HLJDTAF can protect the brain ischemia injury.

Animals↗

PubMed2004

[Research advances of genodermatosis in China].

Research in the field of genetic skin disease has grown rapidly over the past two decades. Even though the fundamental molecular pathways are still not fully understood, there have prominent advances in our understanding of the underlying mechanisms involved in the pathogenesis of genodermatosis. Dermatologists in China contributed to this field in recent years. They found the causative genes involved in primary erythermalgia and familial trichoepithelioma. Different gene mutations involved in more than twenty kinds of genodermatosises have been detected. This review will synthesize recent findings of the genodermatosises in China.

China↗

PubMed2004

Plasma induced degradation of Indigo Carmine by bipolar pulsed dielectric barrier discharge(DBD) in the water-air mixture.

Degradation of the Indigo Carmine (IC) by the bipolar pulsed DBD in water-air mixture was studied. Effects of various parameters such as gas flow rate, solution conductivity, pulse repetitive rate and ect., on color removal efficiency of dying wastewater were investigated. Concentrations of gas phase o3 and aqueous phase H2O2 under various conditions were measured. Experimental results showed that air bubbling facilitates the breakdown of water and promotes generation of chemically active species. Color removal efficiency of IC solution can be greatly improved by the air aeration under various solution conductivities. Decolorization efficiency increases with the increase of the gas flow rate, and decreases with the increase of the initial solution conductivity. A higher pulse repetitive rate and a larger pulse capacitor C(p) are favorable for the decolorization process. Ozone and hydrogen peroxide formed decreases with the increase of initial solution conductivity. In addition, preliminary analysis of the decolorization mechanisms is given.

Air↗

PubMed2004

[Dynamics of species diversity in artificial restoration process of subalpine coniferous forest].

Through plot investigation and by adopting the concept of space as a substitute for time, the developments of species diversity of trees, shrubs and herbaceous plants in subalpine coniferous plantations at different restoration stages were studied, and the correlation coefficients of species in each layer were discussed. The results indicated that in the restoration process, the species richness, diversity and evenness in subalpine coniferous plantations were gradually increased in a fluctuating way. The restoration process of Picea asperata plantations showed a tendency of development that in favor of resuming species diversity. The indices of species richness (species number and Margalef index) and species diversity (Shannon-Wiener index and Simpson index) of trees increased rapidly from the early stages of plantation establishment to the stage of canopy closing (about 30 yr of stand age) and then presented a tendency of decrease with some slight fluctuations, while the index of species evenness showed a periodical rising trend. For the shrub layer, the indices of species richness (Simpson index and Macintosh index) gradually increased with increasing restoration years, whereas the indices of species diversity (Shannon-Wiener index) decreased in the early stages, sharply increased during the stages of canopy closing, and then slowly decreased, which exhibited a tendency of high-->low-->high. In the layer of herbaceous plants, the indices of species richness (Margalef index and number of species) and species diversity (Simpson index, Macintosh index and Shannon-Wiener index) presented a trend of decrease in the early stages of plantations establishment to canopy closing and increased later on. During this process, herbaceous species and their life forms changed greatly, with shade tolerant species gradually substituting the intolerant species. Among the plantations of different stand ages, the average correlation coefficients of trees, shrubs and herbaceous species were 41.88%, 50.61% and 37.22%, respectively, indicating that in the 70 years of artificial forest restoration, the continuity and stability of shrub species were the highest, those of herbaceous species showed greatest fluctuation because of the disappearance and regeneration occurred with the alteration of the environmental conditions of plantations, and those of the trees were intermediary.

Altitude↗

PubMed2004

[Gene transfer of a beta-adrenergic receptor kinase inhibitor up-regulates the level of beta2-adrenergic receptor and cyclic adenosine monophosphate in the asthmatic murine lung].

OBJECTIVE: To investigate the effects of gene transfer of a beta-adrenergic receptor (beta(2)AR) kinase inhibitor (betaARKct) on pulmonary beta(2)-adrenergic receptor and cyclic adenosine monophosphate (cAMP) following beta(2)AR agonist treatment in asthmaticmice, and to analyze the relationship between the routes of gene delivery and the changes of beta(2)AR and cAMP. METHODS: (1)Thirty-five BALB/c mice were sensitized and challenged by 10% and 5% ovalbumin respectively to establish the asthmatic model and then divided into 7 groups (5 each). Sterile saline was injected intramuscularly in the asthmatic control group (group B), while beta(2)AR agonist (salbutamol) was injected intramuscularly in other 5 asthmatic groups (group C, D, E, F, and G) so as to establish the asthmatic model with prolonged application of beta(2)AR agonist. In addition, 5 healthy mice served as the normal control group (group A). (2) The plasmid with the expression of betaARKct was constructed and gene transfer was performed through intravenous injection or intratracheal instillation in asthmatic mice. Intravenous injection with plasmid-betaARKct was performed in group D, but with plasmid-pcDNA 3.1 in group E. Intratracheal instillation with plasmid-betaARKct was performed in group F, but with plasmid-pcDNA 3.1 in group G. (3) The gene expression was measured with Western blot analysis. Radioimmunoassay was used to evaluate the changes of pulmonary beta(2)AR and cAMP. RESULTS: (1) The expression of transferred betaARKct gene was detectable in the lungs. The level of betaARKct expression was higher in the lungs of mice receiving intratracheal plasmid (group F) than those receiving intravenous plasmid (group D). (2) The levels of beta(2)AR and cAMP in group A were (109 +/- 11) fmol/mg and (3.50 +/- 0.50) pmol/L respectively; The levels of beta(2)AR and cAMP in group B were (81 +/- 3) fmol/mg and (1.50 +/- 0.20) pmol/L respectively; the differences between the two groups were significant (all P < 0.05). The levels of beta(2)AR and cAMP in group C were (63 +/- 3) fmol/mg and (0.90 +/- 0.10) pmol/L respectively, and the differences were significant, as compared with those in group A (all P < 0.01). (3) The levels of beta(2)AR and cAMP in group D were (86 +/- 11) fmol/mg and (2.01 +/- 0.10) pmol/L respectively after using plasmid-betaARKct to the asthmatic mice treated with beta(2)AR agonist, and the differences were significant, as compared with those in group C (all P < 0.05). The levels of beta(2)AR and cAMP in group F were (107 +/- 13) fmol/mg and (3.30 +/- 0.20) pmol/L respectively, and the differences were significant, as compared with those in group C (all P < 0.05). The extent of up-regulation of beta(2)AR and cAMP was higher in group F than that in group D (all P < 0.05). The levels of beta(2)AR and cAMP were (70 +/- 11) fmol/mg and (1.30 +/- 0.10) pmol/L in group E, (67 +/- 4) fmol/mg and (3.30 +/- 0.20) pmol/L in group G, respectively, and there were no significant differences between group C and E or G (all P > 0.05). CONCLUSIONS: The results indicated that there was down-regulation of beta(2)AR and cAMP in asthmatic mice (group B), especially in those treated with beta(2)AR agonist (group C). Gene transfer of betaARKct could inhibit the extent of the down-regulation of beta(2)AR and cAMP in asthmatic mice treated with beta(2)AR agonist. The route of gene delivery could also affect the degree of up-regulation of beta(2)AR and cAMP. Gene transfer of betaARKct may provide a novel approach to the therapeutic strategy for asthma.

Animals↗