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Biomedical subjects

Fang Wang

Publications and source records attributed to Fang Wang.

At least 73 records · Page 4Linked to original sources
PubMed2006

Risk factors of diabetic retinopathy in type 2 diabetic patients.

BACKGROUND: Advances in treatment have greatly reduced the risk of blindness from this disease, but because diabetes is so common, diabetic retinopathy remains an important problem. The purpose of this study is to investigate the risk factors of diabetic retinopathy (DR) in Chinese type 2 diabetic patients. METHODS: Totally 746 type 2 diabetic patients were selected for biochemical and clinical characteristics test and examined by the retina-camera for diabetic retinopathy and the average age was 55.9 years old. RESULTS: A total of 526 patients was classified as non-DR, 159 patients as non-proliferative-DR and 61 patients as proliferative-DR. Duration of diabetes [(66.09 +/- 72.51) months vs (143.71 +/- 93.27) months vs (174.30 +/- 81.91) months, P = 0.00], systolic blood pressure [(131.95 +/- 47.20) mmHg vs (138.71 +/- 21.36) mmHg vs (147.58 +/- 24.10) mmHg, P = 0.01], urine albumin [(32.79 +/- 122.29) mg/L vs (190.96 +/- 455.65) mg/L vs (362.00 +/- 552.51) mg/L, P = 0.00], glycated hemoglobin (HbA1c) [(8.68 +/- 2.26)% vs (9.42 +/- 1.84)% vs (9.42 +/- 1.96)%, P = 0.04], C-reactive protein (CRP) [(3.19 +/- 7.37) mg/L vs (6.36 +/- 23.59) mg/L vs (3.02 +/- 4.34) mg/L, P = 0.03], high-density lipoprotein cholesterol (HDL-C) [(1.23 +/- 0.37) mmol/L vs (1.33 +/- 0.35) mmol/L vs (1.24 +/- 0.33) mmol/L, P = 0.01], uric acid (UA) [(288.51 +/- 90.85) mmol/L vs (300.29 +/- 101.98) mmol/L vs (337.57 +/- 115.09) mmol/L, P = 0.00], creatinine (CREA) [(84.22 +/- 16.31) micromol/L vs (89.35 +/- 27.45) micromol/L vs (103.28 +/- 48.64) micromol/L, P = 0.00], blood urine nitrogen (BUN) [(5.62 +/- 1.62) mmol/L vs (6.55 +/- 2.74) mmol/L vs (8.11 +/- 3.60) mmol/L, P = 0.00] were statistically different among the three groups. Logistic regression analysis showed that diabetic duration and urine albumin were two independent risk factors of DR (the OR values were 1.010 and 1.003 respectively). CONCLUSIONS: Diabetic duration and urine albumin are two independent risk factors of diabetic retinopathy in elderly type 2 diabetic patients.

Adolescent↗
PubMed2006

Wheat D-type cyclin Triae;CYCD2;1 regulate development of transgenic Arabidopsis plants.

The D-type cyclin genes play key roles in plant development of Arabidopsis. To investigate the functions of cyclins in monocots, a putative ortholog of cyclin D2 genes was isolated from wheat shoot tissues, and designated as Triae;CYCD2;1. The transcripts of Triae;CYCD2;1 were primarily localized in the proliferating tissues, particularly, in shoot apical meristem and leaf primordia of wheat plants. Ectopic expression of Triae;CYCD2;1 in Arabidopsis affected plant morphology and retarded plant growth. Further examination showed that the promotion of cell division and the inhibition of cell differentiation occurred in both transgenic plants and tissues. In vitro experiments indicated that Triae;CYCD2;1 had functional roles in responding to cytokinin and auxin. Molecular analysis revealed that the transcript levels of several cell cycle-associated genes, particularly Arath;CYCD3;1, were increased in the Arabidopsis plants with the expressing Triae;CYCD2;1. The results in this study provide new information on D-type cyclin in wheat.

Amino Acid Sequence↗
PubMed2006

Electrochemical oxidation of morin and interaction with DNA.

A poly (tetrafluroethylene)-deoxyribonucleate acid (PTFE-DNA) film-modified glassy carbon electrode (GCE) has been fabricated. The electrochemical oxidation behaviors of morin as well as its interaction with DNA have been studied at PTFE-DNA film-modified GCE and bare GCE by electrochemical methods. This modified electrode shows an enhanced effectiveness towards the oxidation of morin. Importantly, as to the interaction between morin and DNA in solution, characteristic parameters such as the binding stoichiometry and association equilibrium constant according to the Hill model for cooperative binding have been determined on the basis of linear sweep voltammetry and chronocoulometry.

Biosensing Techniques↗
PubMed2006

[Resistance to amantadine of epidemic strain of H3 subtype influenza virus: a primary study].

OBJECTIVE: To study the resistance to amantadine of epidemic strain of H3 subtype influenza virus. METHODS: Forty-one strains of influenza virus were isolated from pediatric patients with influenza in Beijing 2004-2005 and were identified as H3 subtype. RNA was extracted. Thirty of the 40 strains were resistant to amantadine with a resistance rate of 75%. The M2 gene ion channel fragments were amplified by one-step RT-PCR, sequenced, and then underwent systemic tree analysis. RESULTS: M2 ion channel associated gene fragment with a molecular size of 153 bp was obtained. The amino acid at the site 31 changed from serine into asparagines, a mutation identical to that of the reference strain A/PR8/34 resistant to amantadine. CONCLUSION: The resistance rate to amantadine is high among the epidemic strains of H3 subtype influenza virus in China. The associated mutation occurs at the site 31 of M2 protein.

Amantadine↗
PubMed2006

Voltammetric sensor for tinidazole based on poly(carmine) film-modified electrode and its application.

A poly(carmine) film-modified glassy carbon electrode (GCE) was fabricated and the electrochemical behavior of tinidazole at the modified electrode was investigated by electrochemical methods. A well-defined reduction peak was observed at 0.61 V and was applied for the determination of tinidazole. Compared with that at a bare GCE, the reduction peak potential of tinidazole shifted negatively and the reduction peak current increased significantly. The influences of some parameters on the reduction of tinidazole were also examined. Based on the experimental data, a possible mechanism was proposed for the electrochemical reaction of tinidazole at the modified electrode. It was found that the reduction peak current was proportional to the concentration of tinidazole in the range from 1.0 x 10(-7) to 5.0 x 10(-5)mol L(-1). The detection limit was about 1.0 x 10(-8)mol L(-1) after accumulation 90 s at a constant potential of 0.0 V. The proposed method was applied to determine tinidazole in drugs and the result was satisfied.

Antitrichomonal Agents↗
PubMed2006

Structure of peer-to-peer social networks.

This paper presents a statistical analysis of the structure of peer-to-peer (P2P) social networks that captures social associations of distributed peers in resource sharing. Peer social networks appear to be mainly composed of pure resource providers that guarantee high resource availability and reliability of P2P systems. The major peers that both provide and request resources are only a small fraction. The connectivity between peers, including undirected, directed (out and in) and weighted connections, is scale-free and the social networks of all peers and major peers are small world networks. The analysis also confirms that peer social networks show in general disassortative correlations, except that active providers are connected between each other and by active requesters. The study presented in this paper gives a better understanding of peer relationships in resource sharing, which may help a better design of future P2P networks and open the path to the study of transport processes on top of real P2P topologies.

Journal Article↗
PubMed2006

Hepatoprotective effect of total flavonoids from Laggera alata against carbon tetrachloride-induced injury in primary cultured neonatal rat hepatocytes and in rats with hepatic damage.

The hepatoprotective activities of total flavonoids of Laggera alata (TFLA) were evaluated by carbon tetrachloride (CCl(4))-induced injury in primary cultured neonatal rat hepatocytes and in rats with hepatic damage. In vitro, TFLA at a concentration range of 1-100 microg/ml improved cell viability and inhibited cellular leakage of two enzymes, hepatocyte aspartate aminotransferase (AST) and alanine aminotransferase (ALT), caused by CCl(4). In vivo, oral treatment with TFLA at doses of 50, 100, and 200 mg/kg significantly reduced the levels of AST, ALT, total protein, and albumin in serum and the hydroxyproline and sialic acid levels in liver. Histopathological examinations revealed that liver damage were improved when treated with TFLA. Meanwhile, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide radicals scavenging activities of TFLA were also determinated. To understand the exact components of TFLA responsible for the hepatoprotective effect, nine flavonoid compounds were isolated and identified from TFLA. In conclusion, the present investigation was the first to verify the hepatoprotective effect of L. alata in vitro and in vivo. The hepatoprotective action of TFLA is likely related to its potent antioxidative and anti-inflammatory activity. Neutralizing reactive oxygen species by nonenzymatic mechanisms and enhancing the activity of original natural hepatic-antioxidant enzymes may be the main mechanisms of TFLA against CCl(4)-induced injury.

Alanine Transaminase↗
PubMed2006

Electroreduction of dioxygen on Aunano-DNA film electrode in acidic electrolyte.

The colloidal Au nanoparticles-deoxyribonucleic acid (Au(nano)-DNA) film modified glassy carbon electrode (GCE) has been fabricated and the electrochemical reduction of dioxygen (O(2)) at this modified GCE has been studied in 0.2 mol/L air-saturated acetate buffer (pH=5.2) using cyclic voltammetry (CV), chronocoulometry (CC), linear scan voltammetry (LSV) and rotating disk electrode (RDE) as diagnostic techniques. The modified electrode shows excellent enhancement effect towards the reduction of dioxygen to hydrogen peroxide (H(2)O(2)), and the overpotential is lower than that at bare GCE. A well-defined dioxygen reduction peak appeared at about -0.24 V. Based on experimental results, a reaction mechanism is proposed and discussed.

Acids↗
PubMed2006

Effects of intravenous urocortin on angiotensin-converting enzyme in rats.

We investigated the relationship between urocortin and the activity of angiotensin-converting enzyme (ACE), which plays a key role in producing the potent vasoconstrictor angiotensin II (Ang II). Urocortin was acutely and subchronically administered to Sprague-Dawley (SD) rats and then the serum and tissue (lung and aorta) ACE levels were evaluated. The tissue ACE mRNA was determined by using reverse transcription and polymerase chain reaction (RT-PCR) analysis. Immunofluorescence studies were also preformed to evaluate the effect of urocortin on ACE in cultured rat aortic endothelial cells (RAECs). Urocortin decreased the serum ACE level 1h after administration, whereas tissue ACE immunoreactivity and mRNA did not change. The prolonged administration of urocortin enhanced tissue ACE activity but the serum ACE level remained low. RT-PCR analysis showed that tissue ACE mRNA was elevated. Immunofluorescence studies also demonstrated an increase of ACE intensity in RAECs exposed to urocortin for 72 h. Corticotropin-releasing factor (CRF) receptor blocker, astressin, abolished the effects of urocortin. Extracellular signal-regulated kinase 1/2 (ERK1/2) pathway blocker, PD98059, also markedly inhibited these effects, suggesting urocortin affects the activity of ACE through the ERK1/2 pathway in rats. These findings support the changes in mean arterial pressure (MAP) following acute and subchronic injections of urocortin in previous studies. Thus, the changes of the ACE activity and its production of Ang II may play a role in the vasodilatory property of urocortin.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2006

Electrochemical behaviors of adrenaline at acetylene black electrode in the presence of sodium dodecyl sulfate.

The electrochemical behaviors of adrenaline at the acetylene black electrode in the presence of sodium dodecyl sulfate (SDS) were investigated by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results indicated that the electrochemical responses of adrenaline were apparently improved by SDS, due to the enhanced accumulation of protonated adrenaline via electrostatic interaction with negatively charged SDS at the hydrophobic electrode surface. This was verified by the influences of different kinds of surfactants on the electrochemical signals of adrenaline. The electrochemical parameters of the adrenaline oxidation were explored by chronocoulometry. Under optimal working conditions, the oxidation peak current at 0.57 V was proportional to adrenaline concentration in the range of 5.0x10(-8) to 7.0x10(-6) mol/L, with a low detection limit of 1.0x10(-8)mol/L for 70s accumulation by differential pulse voltammetry (DPV). This method was applied to determine adrenaline in the hydrochloride injection sample. The results are satisfying compared with that by the standardized method of high performance liquid chromatography (HPLC).

Acetylene↗
PubMed2006

High-level production of bioactive human beta-defensin-4 in Escherichia coli by soluble fusion expression.

Human beta-defensin-4 (hBD4) is a cationic 50-amino acid antimicrobial peptide with three conserved cysteine disulfide bonds. It exhibits a broad antimicrobial spectrum. This study describes the synthesis of hBD4 gene, the heterologous fusion expression of the peptide in Escherichia coli, and the bioactive assay of released hBD4. A PCR-based gene SOEing (splicing by overlap extension) synthesis method was used in the synthesis of the hBD4 gene with optimized codons. By constructing the expression plasmid (pET32-smhBD4), high concentration of soluble hBD4 fusion protein (1.9 g/l) can be obtained in E. coli. Further optimization studies showed that the expression system was very efficient to produce soluble target protein, and the solubility of the target protein could attain more than 99% even when the culture temperature was as high as 37 degrees C. The highest productivity (2.68 g/l) of the hBD4 fusion protein was achieved by cultivating the E. coli (pET32-smhBD4) in MBL medium at 34 degrees C, inducing the culture at the mid-exponential phase with 0.4-mM isopropyl beta-D-galactopyranoside (IPTG), and collecting the broth after 6-h expression. The soluble target protein accounted for 64.6% of the total soluble proteins, and the mature hBD4 expression level was stoichiometrically estimated to be 0.689 g/l. This fusion protein was then purified and cleaved to get the mature hBD4 peptide that showed antimicrobial activity against E. coli and Pseudomonas aeruginosa.

Antimicrobial Cationic Peptides↗
PubMed2006

Vitamin E inhibits hemolysis induced by hemin as a membrane stabilizer.

Hemin is a potential cytolytic agent. To test the effect of vitamin E on hemin-mediated permeability in cell membranes, sheep erythrocytes were chosen as an appropriate model to study hemolysis induced by hemin. Hemin-induced hemolysis but did not elicit lipid peroxidation in sheep erythrocytes. Vitamin E was effective in inhibiting hemin-mediated hemolysis. Both chromanol ring and the isoprenoid side chain of tocopherols were essential for inhibition of hemin-induced hemolysis. There was a strong correlation between the inhibitory effects of tocopherols on hemin-induced erythrocyte hemolysis and their effects on fluorescence anisotropy of cell membranes. Our results suggested that, in contrast to its antioxidant activity, vitamin E inhibits hemolysis induced by hemin as a membrane stabilizing agent.

Animals↗
PubMed2006

Single cell analysis of PKC activation during proliferation and apoptosis induced by laser irradiation.

Laser irradiation has been shown to trigger cellular proliferation and apoptosis in various cell types. Studying the signaling pathways involved in the laser irradiation is important for understanding these processes. In present study, to monitor the protein kinase Cs (PKCs) activity in living cells in real time, we transfected and screened human lung adenocarcinoma cells (ASTC-a-1) stably expressing C kinase activity reporter (CKAR) constructed based on fluorescence resonance energy transfer (FRET) technique. The CKAR is a specific, reversible reporter of phosphorylation by PKCs and it can monitor the ongoing balance between PKCs and phosphatases. The increasing dynamics of PKCs activity is monitored during cell proliferation induced by low-power laser irradiation (LPLI) (0.8 J/cm2) in serum-starved ASTC-a-1 cells stably expressing CKAR reporter using FRET imaging on laser scanning confocal microscope and using spectrofluorometric analysis on a luminescence spectrometer, respectively. However, the decreasing dynamics of PKCs activity has been monitored in real time using FRET imaging for the cells treated with high fluence LPLI (60 J/cm2), which was previously found to induce cell apoptosis. Taken together, LPLI induces the ASTC-a-1 cell proliferation by specifically activating PKCs. However, PKCs activity decreases during cell apoptosis induced by high fluence LPLI. Our results indicate that PKCs play an important role in the laser irradiation-induced biological effects.

Apoptosis↗
PubMed2006

Aging-related changes of microglia and astrocytes in hypothalamus after intraperitoneal injection of hypertonic saline in rats.

To examine the aging-related changes of microglia and astrocytes in hypothalamus of rats after intraperitoneal injection of hypertonic saline in rats, old- and young-aged rats were injected with hypertonic saline solution into peritoneal cavity. Lectin histochemical techniques using Ricinus communis agglutinin-1 (RCA-1) and immunocytochemical method employing antibody against glial fibrillary acidic protein (GFAP) were used to demonstrate microglia and astrocytes in the hypothalamus of the rats, and the positively-stained cells were analyzed by computer-assisted image analysis system. Our results showed that the numbers of microglia and astrocytes were significantly increased in the hypothalamus of old-aged rats. After intraperitoneal injection of hypertonic saline, the number of microglia was significantly decreased in the hypothalamus of both young- and old-aged groups. After introperitoneal injection of hypertonic saline, the number of GFAP positive cells was significantly increased in the hypothalamus of young rats, but the number of GFAP positive cells did not show significant change in the hypothalamus of old rats. It is concluded that in the hypothalamus of old-aged rats, the increase of microglia may be related with the aging or degeneration of neurons, and the increase of astrocytes may provide more nourishment required by the aged neurons. The microglia and astrocytes in the hypothalamus of the two group rats may be affected by hypertonic saline, and the response of these cells to the stimuli is characterized by some aging-related changes.

Aging↗
PubMed2006

The translational and transcriptional initiation sites of BmNPV lef-7 gene.

The predicted open reading frame of lef-7 from Bombyx mori nucleopolyhedrovirus (BmNPV) is 45 bp longer at the 5'-terminal and harbors a 42 bp deletion towards the 3' terminal end compared to that of Autograph californica mlulticapsid NPV (AcMNPV). In the present study, to determine whether the BmNPV lef-7 is translated from an initiation site different from that of AcMNPV lef-7, the translational and transcriptional initiation sites of BmNPV lef-7 were examined. A BmNPV mutant, Bmlef7M1(-) was constructed by deleting 11 nucleotides (nt) including the predicted initiation codon ATG. Western blot analysis demonstrated that the size of LEF-7 in BmNPV and Bmlef7M1(-)-infected cells was identical. The LEF-7s in BmNPV and Bmlef7M1(-)-infected cells were both localized in the nuclei as observed using confocal microscopy. Therefore, the presumed initiation codon ATG (at 97059 nt of BmNPV genome) appears to be non-functional for lef-7 translation. The 5'-RACE analysis revealed that transcription of lef-7 mRNA in BmNPV and Bmlef7M1(-)-infected cells both initiated from an ATCATT motif located 26 nt upstream of the second ATG (located at 97014 nt on BmNPV genome), and 20 nt downstream of the presumed initiation codon.

Animals↗
PubMed2006

[Immobilization of lipase on macroporous resin and its application in synthesis of biodiesel in low aqueous media].

Lipase from Candida sp. 99-125 was immobilized by physical adsorption onto macroporous resins. The results showed that the nonpolar resin NKA was the best carrier used in low aqueous media. 98.98% of degree of immobilization can be achieved when the adsorption procedure was performed in the presence of heptane. The hydrolytic activity and the apparent activity recovery of lipase adsorbed on resin in heptane was 4.07 and 3.43 times higher than that of lipase adsorbed in sodium phosphate buffer, respectively. The catalytic properties of immobilized lipase for production of biodiesel in low aqueous media were studied. Immobilized lipase displayed the highest activity when the crude enzyme/resin weight ratio was 1.92:1 and the water content(water/oil weight ratio) was 15% at 40 degrees C under pH 7.4. As lipase was adsorbed on NKA in heptane to produce biodiesel, the batch conversion rate can reach 97.3% when a three-step methanolysis protocol was used. After 19 consecutive batches, the conversion rate remained 70.2%.

Candida↗
PubMed2006

Self-organizing and adaptive peer-to-peer network.

In this paper, an algorithm that forms a dynamic and self-organizing network is demonstrated. The hypothesis of this work is that in order to achieve a resilient and adaptive peer-to-peer (P2P) network, each network node must proactively maintain a minimum number of edges. Specifically, low-level communication protocols are not sufficient by themselves to achieve high-service availability, especially in the case of ad hoc or dynamic networks with a high degree of node addition and deletion. The concept has been evaluated within a P2P agent application in which each agent has a goal to maintain a preferred number of connections to a number of service providing agents. Using this algorithm, the agents update a weight value associated with each connection, based on the perceived utility of the connection to the corresponding agent. This utility function can be a combination of several node or edge parameters, such as degree k of the target node, or frequency of the message response from the node. This weight is updated using a set of Hebbian-style learning rules, such that the network as a whole exhibits adaptive self-organizing behavior. The principal result is the finding that by limiting the connection neighborhood within the overlay topology, the resulting P2P network can be made highly resilient to targeted attacks on high-degree nodes, while maintaining search efficiency.

Journal Article↗