Biomedical subjects

Hai Wang

Publications and source records attributed to Hai Wang.

At least 91 records · Page 5Linked to original sources

PubMed2004

[Effects of iptakalim on the proliferation of cultured rabbit pulmonary arterial smooth muscle cells induced by endothelin-1].

OBJECTIVE: To explore the effects of iptakalim on the proliferation of rabbit pulmonary arterial smooth muscle cell(PASMC) induced by endothelin-1(ET-1) in vitro. METHODS: The experimental models of proliferation of rabbit PASMC induced by ET-1 in vitro were established and [(3)H]-thymidine ([(3)H]-TdR) incorporation and flow cytometric analysis(FCA) were used. RESULTS: The value of [(3)H]-TdR incorporation in ET-1 group was increased 1.468 times higher than that in control group. Iptakalim at the concentrations of 10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L lowered [(3)H]-TdR incorporation by (19.8 +/- 4.6)%,(41.2 +/- 9.5)%, (54.7 +/- 10.1)%, declined the total of the DNA synthesis (S) and the mitotic phase (G(2)/M) ratios by (36.6 +/- 5.7)%, (42.6 +/- 4.9)%, (66.3 +/- 4.7)%, and increased the static phase (G(0)/G(1)) ratio by (14.4 +/- 3.0)%, (17.9 +/- 2.6)%, (27.9 +/- 3.2)%, respectively, compared with the value of the cells treated with ET-1 only (P < 0.01). Glibenclimide abolished the effect of iptakalim on [(3)H]-TdR incorporation. CONCLUSION: Iptakalim has an inhibitory effect on PASMC proliferation induced by ET-1 through activating ATP sensitive potassium (K(ATP)) channels.

ATP-Binding Cassette Transporters↗

PubMed2004

[Effects of hypoxic acclimatization on myocardial contents of total protein, malondialdehyde and nitric oxide in rats].

OBJECTIVE: To study the effects of acute hypoxia and acute hypoxia after intermittent hypoxic acclimatization on myocardial contents of total protein, malondialdehyde (MDA) and nitric oxide (NO) in rats. METHOD: Myocardial contents of total protein, MDA and NO were investigated in rats after intermittent hypoxic acclimatization (simulated high altitude 3000 m and 5000 m, 4 h/d, 2 weeks respectively) and normal rats after they were exposed to hypoxia (simulated high altitude 8000 m) for 4 h. RESULT: Compared with normal control rats, the myocardial contents of total protein and NO in acute hypoxic rats were reduced significantly, and the myocardial content of MDA was increased significantly. After intermittent hypoxic acclimatization, the myocardial contents of total protein and NO of rats were significantly higher and the myocardial content of MDA was significantly lower compared with those in acute hypoxic rats. CONCLUSION: After intermittent hypoxic acclimatization, the myocardial contents of total protein and NO of rats were increased significantly and the content of myocardial MDA was decreased significantly. This is one of the biochemical mechanisms of hypoxic acclimatization of the heart.

Acclimatization↗

PubMed2003

Drag force, diffusion coefficient, and electric mobility of small particles. I. Theory applicable to the free-molecule regime.

The transport of small particles in the free-molecule regime is investigated on the basis of gas kinetic theory. Drag force formulations were derived in two limiting collision models-namely, specular and diffuse scattering-by considering the potential force of interactions between the particle and fluid molecules. A parametrized drag coefficient equation is proposed and accounts for the transition from specular to diffuse scattering as particle size exceeds a critical value. The resulting formulations are shown to be consistent with the Chapman-Enskog theory of molecular diffusion. In the limit of rigid-body interactions, these formulations can be simplified also to Epstein's solutions [P. S. Epstein, Phys. Rev. 23, 710 (1924)].

Journal Article↗

PubMed2003

Drag force, diffusion coefficient, and electric mobility of small particles. II. Application.

We propose a generalized treatment of the drag force of a spherical particle due to its motion in a laminar fluid media. The theory is equally applicable to analysis of particle diffusion and electric mobility. The focus of the current analysis is on the motion of spherical particles in low-density gases with Knudsen number Kn>>1. The treatment is based on the gas-kinetic theory analysis of drag force in the specular and diffuse scattering limits obtained in a preceding paper [Z. Li and H. Wang, Phys. Rev. E., 68, 061206 (2003)]. Our analysis considers the influence of van der Waals interactions on the momentum transfer upon collision of a gas molecule with the particle and expresses this influence in terms of an effective, reduced collision integral. This influence is shown to be significant for nanosized particles. In the present paper, the reduced collision integral values are obtained for specular and diffuse scattering, using a Lennard-Jones-type potential energy function suitable for the interactions of a gas molecule with a particle. An empirical formula for the momentum accommodation function, used to determine the effective, reduced collision integral, is obtained from available experimental data. The resulting treatment is shown to be accurate for interpreting the mobility experiments for particles as small as approximately 1 nm in radius. The treatment is subsequently extended to the entire range of the Knudsen number, following a semiempirical, gas-kinetic theory analysis. We demonstrate that the proposed formula predicts very well Millikan's oil-droplet experiments [R. A. Millikan, Philos. Mag. 34, 1 (1917); Phys. Rev. 22, 1 (1923)]. The rigorous theoretical foundation of the proposed formula in the Kn>>1 limit makes the current theory far more general than the semiempirical Stokes-Cunningham formula in terms of the particle size and condition of the fluid and, therefore, more attractive than the Stokes-Cunningham formula.

Journal Article↗

PubMed2003

Extraction of o-phenylphenol from silicone tubing by a sulfobutylether cyclodextrin formulation.

During a compatibility study between a formulation containing sulfobutylether cyclodextrin (SBECD) and silicone tubing, an extraneous peak was observed in the HPLC chromatograms. The extraneous material was identified by LC/MS, MS/MS and UV as a previously unreported tubing extractable, o-phenylphenol (o-PP). Several studies were conducted to assess the impact of formulation and process-related variables on the amount of the o-PP extracted, including contact time, sulfobutylether cyclodextrin concentration, formulation pH, and tubing sterilization and storage conditions. Results show that the concentration of the SBECD, tubing processing and storage conditions and the duration of the study influenced the levels of o-PP extracted. However, the largest contributor to the amount extracted was the lot of tubing tested. The extracted levels varied widely from lot to lot (0.007-3.89microg/cm(2) of tubing surface area). A dynamic study conducted to simulate a manufacturing process also resulted in the extraction of o-PP by the formulation.

Biphenyl Compounds↗

PubMed2003

Development of transgenic fish for ornamental and bioreactor by strong expression of fluorescent proteins in the skeletal muscle.

In the present study, new applications of the transgenic technology in developing novel varieties of ornamental fish and bioreactor fish were explored in a model fish, the zebrafish (Danio rerio). Three "living color" fluorescent proteins, green fluorescent protein (GFP), yellow fluorescent protein (YFP), and red fluorescent protein (RFP or dsRed), were expressed under a strong muscle-specific mylz2 promoter in stable lines of transgenic zebrafish. These transgenic zebrafish display vivid fluorescent colors (green, red, yellow, or orange) visible to unaided eyes under both daylight and ultraviolet light in the dark. The level of foreign protein expression is estimated between 3% and 17% of total muscle proteins, equivalent to 4.8-27.2mg/g wet muscle tissue. Thus, the fish muscle may be explored as another useful bioreactor system for production of recombinant proteins. In spite of the high level of foreign protein expression, the expression of endogenous mylz2 mRNAs was not negatively affected. Furthermore, compared to the wild-type fish, these fluorescent transgenic fish have no advantage in survival and reproduction.

Animals↗

PubMed2003

Persistent organic pollutants in water and surface sediments of Taihu Lake, China and risk assessment.

Organic pollutants, especially persistent organic pollutants were examined in the water and surface sediments of Taihu Lake, China. Both 12 water and 12 sediment samples were collected over the lake. C-18 solid-phase extraction technique was applied to extract organic pollutants in collected water samples. Soxhlet extraction procedure was used to extract organic pollutants in sediment samples. The analysis was performed by GC-MS controlled by a Hewlett Packard chemstation. Two hundred and seventy-three kinds of organic chemicals in water were examined, 200 more than that detected in 1985; 188 kinds of chemicals in sediments were detected as well. Among them 21 kinds of chemicals belong to priority pollutants as well as 17 kinds to be the endocrine disruptors. The concentrations of the pollutants were more than 2 times higher than that in 1985. The possible source and relation to anthropogenic activity were discussed.

China↗

PubMed2003

[Real-time quantitative PCR assay of Epstein-Barr virus in whole blood cells of nasopharyngeal carcinoma patients].

EBV is detected in more and more tumors, and is relative to carcinogenesis. We studied the copies of EBV DNA in whole blood of NPC patients and healthy controls by real-time quantitative PCR. In the 73 NPC patients and 83 controls, the positive rate of EBV in blood of NPC is 46.6%, while 13.3% in control. The mean copy number is 3.9 x 10(4) copys/microgram DNA in controls, which is much higher than NPC patients (which is 1.7 x 10(5) copies/microgram DNA). EBV infection is relative with NPC, while the lytic form of EBV maybe more important than its latent form. These results suggest that whole blood EBV DNA may be a valuable tool for molecular diagnosis of NPC.

Adult↗

PubMed2003

Iptkalim inhibits cocaine challenge-induced enhancement of dopamine levels in nucleus accumbens and striatum of rats by up-regulating Kir6.1 and Kir6.2 mRNA expression.

AIM: To investigate the effect and mechanism of novel ATP-sensitive potassium channel opener (KCO) iptkalim (IPT) on acute and cocaine challenge-induced alterations in the levels of dopamine (DA) and glutamate (Glu) from nucleus accumbens (NAc), striatum, and prefrontal cortex (PFC) in rats. METHODS: The levels of DA and Glu were assayed using high performance liquid chromatography (HPLC) combined with amperometric and fluorescent detection, respectively. The mRNA levels of Kir6.1, Kir6.2, SUR1, and SUR2 were measured by semiquantitative reverse transcription polymerase chain reaction (RT-PCR). RESULTS: IPT did not affect acute cocaine (30 mg/kg, ip)-induced elevations in either DA levels from NAc and striatum or Glu levels from NAc and PFC. An acute cocaine challenge (30 mg/kg, ip) on d 21 after withdrawal caused an elevation in DA levels in NAc and striatum. Moreover, the same treatment also increased Glu levels in PFC and NAc of cocaine-pretreated rats. Repeated IPT injections reversed cocaine challenge-induced DA increase in NAc and striatum. Cocaine challenge increased Kir6.1 and Kir6.2 mRNA expression in striatum and NAc and only elevate Kir6.2 expression in PFC in both cocaine-pretreated rats and rats pretreated with IPT plus cocaine. Moreover, expression of Kir6.1 and Kir6.2 mRNA was augmented in rats pretreated with IPT plus cocaine compared to rats pretreated with cocaine alone. No significant change was found in the SUR1 and SUR2 expression of all four groups. CONCLUSION: IPT inhibited cocaine challenge-induced enhancement of DA levels in NAc and striatum by up-regulating Kir6.1 and Kir6.2 mRNA expression.

Animals↗

PubMed2003

Muscarinic receptor activities potentiated by desensitization of nicotinic receptors in rat superior cervical ganglia.

AIM: The influences of desensitized nicotinic acetylcholine receptors (nAChR) on the activities of muscarinic acetylcholine receptors (mAChR) were investigated in single cultured rat superior cervical ganglion. METHODS: Whole-cell patch-clamp techniques were used. RESULTS: An inward current was induced by nicotine 80 micromol/L in the sympathetic neurons and desensitized rapidly after the prolonged exposure to nicotine. An outward current was induced by oxotremorine 100 micromol/L or pilocarpine 100 micromol/L and it showed no desensitization after exposure to its agonists. After nAChR desensitized completely, the current evoked by oxotremorine was increased significantly compared with its control. There were (42 38) % (n=8, P<0.05) and (165 66) % (n=5, P<0.01) increases induced by 100 and 500 micromol/L oxotremorine, respectively. Similar results were also obtained from pilocarpine and the current evoked by 100 micromol/L pilocarpine increased by (66 33) % (n=6, P<0.05) after nAChR desensitization. Once nicotine was removed, nAChR recovered from desensitization gradually and the enhanced mAChR activity also subsided along with it. Furthermore, the facilitatory effect of desensitized nAChR on mAChR activity could be prevented by mecamylamine. CONCLUSION: The activities of mAChR to its agonists were potentiated by the desensitization of nAChR in rat sympathetic neurons

Animals↗

PubMed2003

Overcoming multi-drug resistance by anti-MDR1 ribozyme.

AIM: To reverse multidrug resistance (MDR) of HepG2 by anti-MDR1 hammerhead ribozyme. METHODS: We developed an anti-MDR1 hammerhead ribozyme and delivered it to P-gp-overproducing human hepatocarcinoma cell line HepG2 by a retroviral vector containing RNA polymerase III promoter. We detected the expression of mdr1/Pgp and Rz in HepG2, HepG2 multidrug-resistant cell line and HepG2 Rz-transfected cells by real-time RT-PCR, semi-quantitative RT-PCR and Western blot methods. Moreover, MTT assay was tested to detect sensitivity of these ribozyme-transfected cells, and Rhodamine123 (Rh123) applied to test the function of Pgp. RESULTS: The Rz- transfected HepG2 cells became doxorubicin-sensitive, concomitant with the decreases in MDR1 expression, P-gp amounts and efflux pump function. CONCLUSION: The approaches using either retrovirus or liposome-mediated transfer of anti-MDR1 ribozyme may be selectively applicable to the treatment of MDR cells.

Antineoplastic Agents↗

PubMed2003

[Advances on zeta protein encoded by Epstein-Barr virus (EBV) BZLF1 gene].

Zeta protein was encoded by BZLF1 gene which is one of Epstein-Barr virus (EBV) immediate early (IE) genes. The protein is a member of activator protein 1 (AP-1) super family that can bind to cellular AP-1 response element. Zeta protein is associated with lots of human diseases, including nasopharyngeal carcinoma (NPC). So detection of Zeta protein or its antibody can be used in disease diagnosis and prognosis assessment. Zeta protein can repress human immune system, interfere with cellular signal transduction, affect cell cycle progress, and induce cell apoptosis. At the same time, its expression can be affected by some cellular components. Here we review the new advances on BZLF1 gene structure, expression and relationship to cells, together with association with EBV associated diseases.

Animals↗

PubMed2003

Salviae miltiorrhizae ameliorates cirrhosis and portal hypertension by inhibiting nitric oxide in cirrhotic rats.

OBJECTIVE: To determine the effect of Salviae miltiorrhizae on cirrhosis and portal hypertension by inhibiting nitric oxide synthase type II (NOSII) in rats. METHODS: Real time RT-PCR was used to detect the expression of NOSII mRNA. The enzymatic activity of nitric oxide synthase and the circulating levels of nitric oxide (NO), systemic and portal hemodynamics, and quantification of cirrhosis were measured with highly sensitive methods. Traditional Chinese medicine was utilized to treat cirrhotic rats and the function of NO was evaluated. Double-blind method was applied in the experiment constantly. RESULTS: The concentration of NO increased markedly at all stages of cirrhosis, and so did the enzymatic activity of NOS, and the iNOSmRNA expressed greatly. Meanwhile the portal-venous-pressure (PVP), portal-venous-flow (PVF) increased significantly. NO, NOS and iNOSmRNA were positively correlated to the quantity of hepatic fibrosis. Salviae miltiorrhizae significantly inhibited NO production and inhibited the expression of iNOSmRNA. CONCLUSIONS: The increased hepatic expression of NOSII is one of the important factors causing cirrhosis and portal hypertension. Salviae miltiorrhizae significantly ameliorates cirrhosis and portal hypertension.

Animals↗

PubMed2003

[Antithrombotic effects of morpholine and piperazine ring derivatives and their molecular mechanism].

AIM: To investigate the antithrombotic effects of morpholine and piperazine ring derivatives and their mechanisms. METHODS: In isolated rat aorta-precontracted with norepinephrine (NE), the vasodilatory effects of compounds with novel structure were investigated. Mice was given kappa-carrageenin i.p. and kept at the temperature of (20-21) degree C. RESULTS AND CONCLUSION: Active candidate compounds including MOPMC, 2FBMPC, MPTMBC, DMHPPP and PPVP were shown to antagonize thrombosis at the dose of 1 mg.kg-1 through activating the endothelial target for acetylcholine; while the contrasting compounds MAPC, 4C3FBMOC, mTBMPC, MONVP and MPNVP showed no significant effect on the tension of isolated aorta strips or significant antithrombotic effects at the same dose. The antithrombotic mechanism of novel compounds is not relevant to hemostatic systems or functions of platelet aggregation directly, but they can promote endothelial cells to release tissue-type plasminogen activator (t-PA) and inhibit the activity of plasminogen activator inhibitor-1 (PAI-1).

Animals↗

PubMed2003

[Study on licorice resources and their sustainable utilization in center and western area of China].

OBJECTIVE: To investigate the latest wild and cultivated licorice resource status; bring forward the licorice resource protection and sustainable utilization countermeasures in the center and western area of China. METHOD: With study both in interview survey and field survey. RESULT: All samples investigated were the species of Glycyrrhiza uralensis. Human actions is concerned with the community status, reserves per unit and quality. Excessive exploitation made the licorice quality lower and reserves decrease. CONCLUSION: Enforcing the wild licorice resource protection and improving licorice cultivated technique are brought forward to act as the sustaining countermeasures.

China↗

PubMed2002

Pharmacological characteristics of the endothelial target for acetylcholine induced vascular relaxation.

The pharmacological characteristics of the endothelial target for acetylcholine induced vascular relaxation were investigated in this experiment. The isolated preparations of arteries were suspended for the measurement of isometric force in modified Krebs-Ringer bicarbonate solution (37 degrees C aerated with 95% O2 and 5% CO2). Similar to acetylcholine, carbachol rather than thiocholine, butylcholine and choline could induce endothelium-dependent relaxation. Among cholinergic receptor agonists, arecoline and oxotremorine rather than nicotine could mimic the effects of acetylcholine. But muscarinic agonist pilocarpine had no effect. This phenomenon was observed in rat, cat and rabbit aorta, as well as cat mesenteric. femoral and renal arteries. The new compound tricyclopinate and phenyl cyclopentyl hydroxyl-ethoxy quinuclidines, the competitive antagonists against muscarinic receptors, displayed noncompetitive antagonism against the endothelial target for acetylcholine. Among the six isomers of the novel compound 2-(2'-cyclopentyl-2'-phenyl-2'-hydroxyl-ethoxy) tropane, the isomers with IS-2alpha-2'R and 1S-2alpha-2'S configuration caused the dose-response curves of acetylcholine for inducing vascular relaxation shift rightward with a parallel manner, while the isomers IR-2alpha-2'R and IR-2alpha-2'S with a nonparallel manner. In addition, the antagonistic effects of the isomer IS-2alpha-2'R against the endothelial target for acetylcholine and against muscarinic receptors were 4570 and 10 times greater than those of the isomer IS-2alpha-2'S respectively. In conclusion, the endothelial target for acetylcholine had the unique pharmacological characteristics different from those of muscarinic receptors.

Acetylcholine↗

PubMed2002

Pharmacological characteristics of novel putative purinoceptors in vascular endothelium.

Using an isolated rat aorta with intact endothelium, a functional bioassay system was created as follows: pre-contract the isolated rat aorta with intact endothelium in the presence of 0.62 micromol/l of norepinephrine, and then add acetylcholine to obtain maximal endothelium-dependent relaxation. In the addition of low concentration of adenosine, a P(1) agonist or ATP, a P(2) agonist to this system, the rat aorta smooth muscle contraction was observed. This observation could not be explained in terms of the classic P(1) and P(2) receptor properties, suggesting that there may be a novel subtype of purinoceptors in the endothelium of the rat aorta. The P(1) and P(2) agonists-induced rat aorta smooth muscle contraction could be blocked by the pretreatments of the bioassay system with a G protein (Gi/o) inhibitor, PTX, and EDNO synthesis inhibitor, L-NAME and cyclooxygenase inhibitor, indomethacine. The data strongly support that this novel purinoceptor may couple with PTX-sensitive G protein, Gi or Go, and the novel purinoceptor-mediated rat aorta smooth muscle contraction is dependent on the endogenous nitric oxide and prostaglandin synthesis. In an additional observation, pathophysiological conditions, such as hypertension, altered the characteristics of the novel receptor. Hypertension caused the novel receptor insensitive to adensone and uncoupling to PTX-sensitive G-proteins and lost of ability to initiate the receptor-mediated prostaglandin synthesis. All together, the novel putative endothelial purinoceptor may play an important role in the control of vascular tone in physiological or pathophysiological statues.

Animals↗

PubMed2002

Persistent organic pollutants (POPs) in surface sediments of Donghu Lake, Wuhan, Hubei, China.

Surface sediment samples from five different sites were collected in Donghu Lake, Wuhan City, Hubei Province, China during November 2000. Over 180 organic chemicals were detected using GC-MS controlled by a Hewlett Packard Chemstation after soxhlet extraction. Derivatives of benzene, phthalate esters, PAHs, phenols, isophorone as priority pollutants or endocrine disruptors, respectively, were detected. The concentration of organic pollutants were found to be highest at the sampling site located at Southwest Donghu Lake (Shuiguo), caused most probably by the untreated wastewater discharge, average at the southern and lowest at the northern part of the lake.

China↗