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Biomedical subjects

Wei Lu

Publications and source records attributed to Wei Lu.

At least 181 records · Page 10Linked to original sources
PubMed2003

[Clinical study on the comparison of prophylactic tracheotomy with emergent tracheotomy after inhalation injury].

OBJECTIVE: To compare prophylactic with emergent tracheostomy in 93 patients with inhalation injury, so as to explore the clinical significance of prophylactic tracheostomy. METHODS: Tracheostomy was applied in all patients with moderate and severe inhalation injury. The patients with obvious dyspnea, low oxygen pressure and decreased oxygen saturation before the operation were set to be emergent tracheostomy group (ET, n = 21), while those without dysfunction of ventilation and gas exchange, as prophylactic group (PT, n = 72). The average operation starting time was 4.31 +/- 3.04 PBH and 34.47 +/- 2.79 PBH in PT and ET groups, respectively. RESULTS: There were evident decrease of blood oxygen pressure and oxygen saturation and increase of respiratory and heart rates before the tracheostomy in ET group, but all these signs improved after the operation. In contrary, the vital signs in PT group exhibited stable perioperatively. Assisted respiration with respirator was applied in 20 cases (95.24%) in ET and in 65 cases (90.28%) in PT groups within 2 post-operative days (POD). CONCLUSION: Early and prophylactic tracheostomy should be advocated in patients suspected to be with moderate or severe inhalation injury. Emergent tracheostomy must be avoided and respiratory assistance should be employed as early as possible.

Adolescent↗
PubMed2003

[Intravascular administration of pingyangmycin lipiodol emulsion for Klippel-Trenaunay syndrome: clinical analysis of 7 cases].

OBJECTIVE: To define the arteriographic features of Klippel-Trenaunay sydrome (KTS) and explore the feasibility of the treatment with intravascular administration of pingyangmycin lipiodol emulsion (PLE). METHODS: Seven patients with KTS underwent arteriography followed by therapy with PLE administration (containing pingyangmycin 8-16 mg and lipiodol 4-6 ml) into the trunk of the arteries of all impaired extremities. The therapeutic effect and postoperative complications were observed. RESULTS: Arteriography revealed abundant small branches of the runoff arteries, showing sinusoid changes of varied sizes in 5 cases by staining of the soft tissue. During the 3 to 30-month follow-up, swelling of the extremities was obviously improved in 5 cases after PLE therapy, which failed to produce obvious effect in 1 case and recurrence was detected in another. The major complications included paresthesia of the limbs, serum transaminase disorder and local skin necrosis. CONCLUSION: Arteriography can detect the lesions of the arteries and soft tissues in the affected extremity of patients with KTS, intravascular administration of PLE was effective to alleviate the hypertrophy of the limbs.

Adolescent↗
PubMed2003

[Study on the prevalence of arthritis and relevant factors in Shanghai].

OBJECTIVE: This study aimed to understand the prevalence rate, epidemiological characteristics and relevant factors of arthritis in Shanghai. METHODS: A sample of 7 575 residents aged 15 years and above was drawn from 6 communities under multiple stage cluster sampling. A household survey with questionnaire was carried out to differentiate both undiagnosed patients and those with definite arthritis. Those who had not been diagnosed before were asked to carry further clinical examinations by a rheumatologist. RESULTS: The prevalence rate of arthritis was 6.11%, including osteoarthritis (OA) 4.18%, rheumatoid arthritis (RA) 0.52%, gout 0.28%, ankylosing spondylitis (AS) 0.28%, rheumatic arthritis 0.49% and other types arthritis 0.82%. Arthritis was significantly related to cardiovascular disease, pulmonary disease and gastrointestinal disease. Age, female and obesity might serve as risk factors for arthritis. Physical labors and living in rural area might have protecting effects. CONCLUSION: Elderly and female seemed to be at high risk for arthritis. Weight control and more exercise should be encouraged to reduce the risks. For arthritis patients, treatment to other chronic diseases should not be ignored.

Adolescent↗
PubMed2003

Pharmacokinetics of sibutramine hydrochloride in Chinese healthy volunteers.

AIM: To evaluate the pharmacokinetic profiles of the pharmacologically active primary amine metabolite of sibutramine, N-di-desmethyl sibutramine (BTS 54505) in Chinese origin. METHODS: According to a randomized cross-over design, a single oral dose of 20 mg of sibutramine hydrochloride capsule was given to 20 healthy Chinese young volunteers. After dosing, serial blood samples were collected for a period of 72 h. BTS 54505 concentration in plasma was analyzed by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. RESULTS: Various pharmacokinetic parameters including AUC0-t, AUC0-infinity, Cmax, Tmax, T1/2, Kelm and MRT were determined for both test and reference capsules and found to be in good agreement with literature values. CONCLUSION: The test and reference sibutramine capsules were bioequivalent.

Administration, Oral↗
PubMed2002

Therapeutic dendritic-cell vaccine for simian AIDS.

An effective immune response against human immunodeficiency virus or simian immunodeficiency virus (SIV) is critical in achieving control of viral replication. Here, we show in SIV-infected rhesus monkeys that an effective and durable SIV-specific cellular and humoral immunity is elicited by a vaccination with chemically inactivated SIV-pulsed dendritic cells. After three immunizations made at two-week intervals, the animals exhibited a 50-fold decrease of SIV DNA and a 1,000-fold decrease of SIV RNA in peripheral blood. Such reduced viral load levels were maintained over the remaining 34 weeks of the study. Molecular and cellular analyses of axillary and inguinal node lymphocytes of vaccinated monkeys revealed a correlation between decreased SIV DNA and RNA levels and increased SIV-specific T-cell responses. Neutralizing antibody responses were augmented and remained elevated. Inactivated whole virus-pulsed dendritic cell vaccines are promising means to control diseases caused by immuno- deficiency viruses.

2,2'-Dipyridyl↗
PubMed2002

Organic triplet emissions of arylacetylide moieties harnessed through coordination to [Au(PCy(3))]+. Effect of molecular structure upon photoluminescent properties.

A family of mono- and binuclear Cy(3)P-supported gold(I) complexes containing various pi-conjugated linear arylacetylide ligands, including the two homologous series (Cy(3)P)Au(Ctbd1;CC(6)H(4))(n)()(-)(1)(Ctbd1;CPh) and (Cy(3)P)Au(Ctbd1;CC(6)H(4))(n)()Ctbd1;CAu(PCy(3)) (n = 1-4), have been prepared. X-ray crystal analyses revealed no intermolecular aurophilic interactions in their crystal lattice. The lowest-energy singlet transitions are predominately intraligand in nature and exhibit both phenyl and acetylenic (1)(pipi) character. Strong photoluminescence is detected in solid and solution states under ambient conditions, with lifetimes in the microsecond regime. For complexes with a single arylacetylide group, only phosphorescence from the arylacetylide (3)(pipi) state is observed. Vibrational spacings in the solid-state emission spectra can be attributed to a combination of phenyl ring deformation and symmetric phenyl ring and Ctbd1;C stretches. Additional delayed-fluorescence emission is recorded for complexes with multiple p-arylacetylide units, and this is attributed to a triplet-triplet annihilation process. The phosphorescence energy of these complexes are readily modified by altering the length of the conjugated arylacetylide system, while the intensity of phosphorescence relative to fluorescence decreases when the p-arylacetylide chain is elongated. Information regarding the nature and relative energies of arylacetylide singlet and triplet excited states has been derived from the two homologous series and extrapolated to polymeric arylacetylide species. The (3)(pipi) excited-state reduction potentials E degrees [Au(+)/Au] (Au = 1a, 2, and 4) are estimated to be -1.80, -1.28, and -1.17 V versus SSCE, respectively.

Journal Article↗
PubMed2002

The role of C-terminal tyrosine phosphorylation in the regulation of SHP-1 explored via expressed protein ligation.

The protein-tyrosine phosphatase SHP-1 plays a variety of roles in the "negative" regulation of cell signaling. The molecular basis for the regulation of SHP-1 is incompletely understood. Whereas SHP-1 has previously been shown to be phosphorylated on two tail tyrosine residues (Tyr(536) and Tyr(564)) by several protein-tyrosine kinases, the effects of these phosphorylation events have been difficult to address because of the intrinsic instability of the linkages within a protein-tyrosine phosphatase. Using expressed protein ligation, we have generated semisynthetic SHP-1 proteins containing phosphotyrosine mimetics at the Tyr(536) and Tyr(564) sites. Two phosphonate analogues were installed, phosphonomethylenephenylalanine (Pmp) and difluorophosphonomethylenephenylalanine (F(2)Pmp). Incorporation of Pmp at the 536 site led to 4-fold stimulation of the SHP-1 tyrosine phosphatase activity whereas incorporation at the 564 site led to no effect. Incorporation of F(2)Pmp at the 536 site led to 8-fold stimulation of the SHP-1 tyrosine phosphatase activity and 1.6-fold at the 564 site. A combination of size exclusion chromatography, phosphotyrosine peptide stimulation studies, and site-directed mutagenesis led to the structural model in which tyrosine phosphorylation at the 536 site engages the N-Src homology 2 domain in an intramolecular fashion relieving basal inhibition. In contrast, tyrosine phosphorylation at the 564 site has the potential to engage the C-Src homology 2 domain intramolecularly, which can modestly and indirectly influence catalytic activity. The finding that phosphonate modification at each of the 536 and 564 sites can promote interaction with the Grb2 adaptor protein indicates that the intramolecular interactions fostered by post-translational modifications of tyrosine are not energetically strong and susceptible to intermolecular competition.

Escherichia coli↗
PubMed2002

[Molecular mechanism of nitric oxide in preventing cardiomyocytes from hypertrophic response induced by angiotensin II].

The aim of this study was to determine the molecular mechanism of nitric oxide (NO) in preventing cardiomyocytes from hypertrophic response induced by angiotensin II (Ang II). Hypertrophic response of neonatal rat cardiomyocytes was assayed by protein synthesis rate and expression of atrial natriuretic peptide (ANP) mRNA. The level of NO was shown by the content of nitrate and nitrite in cardiac myocytes. The protein expression of MKP-1 and the gene expression of eNOS were measured with Western blotting and RT-PCR, respectively. The results are as follows. (1) L-arginine (L-Arg) induced a dose-dependent increase in NO by 16% and 31% at the concentrations of 10 micromol/L and 100 micromol/L, respectively. L-Arg also increased the gene expression of eNOS. However, these effects were inhibited by L-NAME, the inhibitor of NOS. (2) The gene expression and the protein synthesis of ANP induced by Ang II (0.1 micromol/L) were inhibited by L-Arg (100 micromol/L). The inhibitory action of L-Arg was abolished after pretreatment with antisense oligoneucleotide against MKP-1. (3) L-Arg (100 micromol/L) increased the protein expression of MKP-1 by 225%, which was inhibited by L-NAME, an NOS inhibitor, and KT-5823, a cGMP-dependent protein kinase (PKG) inhibitor. However, Ang II enhanced the effect induced by L-Arg. The above results show that NO may activate PKG, and thereby promote the protein expression of MKP-1 and inactivate MAPK, resulting in an inhibition of cardiomyocyte hypertrophic response induced by Ang II.

Angiotensin II↗
PubMed2002

Mutational analysis of the central centromere targeting domain of human centromere protein C, (CENP-C).

Human centromere protein C (CENP-C) is an essential component of the inner kinetochore plate. A central region of CENP-C can bind DNA in vitro and is sufficient for targeting the protein to centromeres in vivo, raising the possibility that this domain mediates centromere localization via direct DNA binding. We performed a detailed molecular dissection of this domain to understand the mechanism by which CENP-C assembles at centromeres. By a combination of PCR mutagenesis and transient expression of GFP-tagged proteins in HeLa cells, we identified mutations that disrupt centromere localization of CENP-C in vivo. These cluster in a 12 amino acid region adjacent to the core domain required for in vitro DNA binding. This region is conserved between human and mouse, but is divergent or absent in invertebrate and plant CENP-C homologues. We suggest that these 12 amino acids are essential to confer specificity to DNA binding by CENP-C in vivo, or to mediate interaction with another as yet unidentified centromere component. A differential yeast two-hybrid screen failed to identify interactions specific to this sequence, but nonetheless identified 14 candidate proteins that interact with the central region of CENP-C. This collection of mutations and interacting proteins comprise a useful resource for further elucidating centromere assembly.

Amino Acid Sequence↗
PubMed2002

[(C(wedge)N(wedge)N)Pt(C identical to C)nR] (HC(wedge)N(wedge)N = 6-aryl-2,2'-bipyridine, n = 1-4, R = aryl, SiMe3) as a new class of light-emitting materials and their applications in electrophosphorescent devices.

Tridentate cyclometalated platinum(II) complexes bearing sigma-alkynyl ligands exhibit tunable photoluminescence and enhanced stability during vacuum deposition; OLEDs based on these materials display orange to red electrophosphorescence with low turn-on voltages (approximately 4 V), maximum luminance approaching 10,000 cd m-2 and efficiency up to 4.2 cd A-1.

Journal Article↗
PubMed2002

Interaction between metabotropic and NMDA subtypes of glutamate receptors in sprout suppression at young synapses.

Recently, NMDA receptors (NMDARs) have been implicated in a cell contact-dependent suppression of sprouting in cultured Xenopus tectal neurons during an early period when neither AMPA/kainate (KA) receptors nor action potentials play a prominent role in cell-cell communication. We asked how the NMDA receptors function in the absence of the depolarizing effect of AMPA/KA receptor activity. We show that type II metabotropic glutamate receptors (mGluRs) can operate synergistically with NMDA receptors in the absence of AMPA/KA receptor function to suppress an early neurite sprouting response of the tectal neurons. Calcium imaging with fluo-3 AM and morphological analyses after exposure to glutamate receptor antagonists show that a combination of AMPA/KA receptor and type II mGluR blockers mimics the decrease in intracellular free calcium in response to glutamate and the structural effects produced by NMDA receptor antagonists in these cultures. Patch-clamp analyses confirmed a decrease in NMDA receptor-mediated currents with type II mGluR blockade, and 8-bromo cAMP application produced a decrease in NMDA receptor-mediated calcium influx. These data suggest that type II mGluRs potentiate NMDA receptor function by decreasing cAMP levels in tectal neurons. We also show that NMDARs exhibit low magnesium sensitivity in tectal neurons during the first few days in culture. Thus both metabotropic and ionotropic glutamate receptors can play a role in the contact-mediated suppression of ongoing sprouting at early neuron-neuron contacts before action potential activity.

Animals↗
PubMed2002

Genomic instability of prawn white spot bacilliform virus (WSBV) and its association to virus virulence.

Prawn White Spot Bacilliform Virus (WSBV) is a major pathogen that causes prawn diseases. In this study, we examined the sequence of WSBV genome DNA in the shrimp Penaeus japonicus, P. vannamei, P. Monodon, P. chinensis and Metapenaeus ensis through successive PCR amplification of the DNA fragments in the whole WSBV genome. We found a sequence deletion hotspot in the WSBV genome that is 305107 bp in length. The sizes of the deleted fragments were 4.6, 4.8 or 8.1 kbp depending on the species of prawn. Since the mortality of shrimp infected by the intact WSBV was always significantly higher than that of shrimp infected by DNA fragment-deleted WSBV, we suggest that this deletion be somehow linked to the virulence of the virus itself. This result may lead to the discovery of the molecular mechanism of the pathogenicity of WSBV in shrimps.

Animals↗
PubMed2002

Syntheses of two cytotoxic sinapyl alcohol derivatives and isolation of four new related compounds from Ligularia nelumbifolia.

Phytochemical reinvestigation on Ligularia nelumbifolia afforded four novel sinapyl alcohol analogues named nelumols B-E (1-4) and three known sinapyl alcohol derivatives (5-7). Their structures were elucidated by NMR techniques. Total syntheses of cytotoxic geranyloxy sinapyl alcohol (6) and geranyloxy sinapyl aldehyde (7) were carried out via two different paths. The 4-O-benzyl-substituted analogues (20 and 27) as well as the 4-O-(2-methylbutenyl) derivatives (34 and 35) were also synthesized. The cytotoxicities of 6 and 7 were measured using A-549, HL-60, and KB cancer cell lines.

Alcohols↗
PubMed2002

A sensitive and selective assay of nucleic acids by measuring enhanced total internal reflected resonance light scattering signals deriving from the evanescent field at the water/tetrachloromethane interfacet.

A total internal reflected resonance light scattering (TIR-RLS) technique, the coupling of resonance light scattering (RLS) technique with total internal reflected light at the interface of two immiscible liquids, where the steep change of the refractive indexes occurs to result in an evanescent field, is proposed with the characteristics of separation and enrichment properties of analytes and direct use of oil-soluble reagents free from surfactants. At pH 8.69 and ion strength 0.008, ternary amphiphilic species formed by the interaction of nucleic acids, including calf thymus DNA (ctDNA), fish sperm DNA (fsDNA), and yeast RNA (yRNA), with Eu(III) in the presence of oil-soluble trioctylphosphine oxide (TOPO), are adsorbed to the water/tetrachloromethane (H20/CCl4) interface, giving rise to significantly enhanced TIR-RLS signals. It has been found that the enhanced TIR-RLS intensity at 348.0 nm is proportional to the concentration of thermally denatured ctDNA, fsDNA and yRNA in the range 0.002-2.5 microg ml(-1), 0.002-2.5 microg ml(-1) and 0.003-2.0 microg ml(-1), respectively and their limits of determination (3sigma) are 0.16 ng ml(-1), 0.19 ng ml(-1) and 0.28 ng ml(-1), correspondingly. Complicated artificial samples with highly interfering backgrounds were determined satisfactorily.

Nucleic Acids↗
PubMed2002

Clevidipine in adult cardiac surgical patients: a dose-finding study.

BACKGROUND: Treatment of elevated blood pressure is frequently necessary after cardiac surgery to minimize postoperative bleeding and to attenuate afterload changes associated with hypertension. The purpose of this study was to investigate the pharmacodynamics and pharmacokinetics of a short-acting calcium channel antagonist, clevidipine, in the treatment of hypertension in postoperative cardiac surgical patients. METHODS: Postoperative cardiac surgical patients were randomized to receive placebo or one of six doses of clevidipine. Hemodynamic parameters were recorded and blood samples were drawn for determination of clevidipine plasma concentrations during infusion and after discontinuation of clevidipine. The concentration-response relation was analyzed using logistic regression, and pharmacokinetic models were applied to the data using population analysis. RESULTS: There were significant decreases in mean arterial blood pressure and systemic vascular resistance at doses greater than or equal to 1.37 microg. kg-1. min-1. There were no changes in heart rate, central venous pressure, pulmonary artery occlusion pressure, or cardiac index with increasing doses of clevidipine. The clevidipine C50 value for a 10% or greater decrease in mean arterial pressure was 9.7 microg/l and for a 20% or greater decrease in mean arterial pressure was 26.3 microg/l. The pharmacokinetics of clevidipine were best described with a three-compartment model with a volume of distribution of 32.4 l and clearance of 4.3 l/min. The early phase of drug disposition had a half-life of 0.6 min. The context-sensitive half-time is less than 2 min for up to 12 h of administration. CONCLUSION: Clevidipine is a calcium channel antagonist with a very short duration of action that effectively decreases systemic vascular resistance and mean arterial pressure without changing heart rate, cardiac index, or cardiac filling pressures.

Algorithms↗
PubMed2002

Direct detection of oxygen free radicals produced in the viscera of burned rats using electron paramagnetic resonance spectroscopy.

OBJECTIVE: To detect superoxide anion (O(-)(2)) signals in the heart, liver, lung and kidney tissues after burns. METHODS: Twenty-four male rats were randomized into 4 groups. The rats of experimental groups were immersed in 100 degrees C water for 15 seconds and 25% third-degree burn was created. Thoracotomy or laparotomy was performed at 5, 10, 15, 20 and 30 minutes after burn, and specimens of the heart, lung, liver kidney were obtained for burned rats. The specimens were then preserved in liquid nitrogen for cryo-preservation and detected immediately using EPR. RESULTS: The signals of superoxide O radical appeared in the heart, lung, 1iver and kidney specimens 10-15 minutes after burn. CONCLUSIONS: There is a direct evidence of oxygen free radicals (OFRs) injury to viscera of burned rats between 10-15 minutes after burn.

Animals↗
PubMed2002

Effect of dosage of anticancer agents during transcatheter arterial chemoembolization on T cell subsets in patients with hepatocellular carcinoma.

OBJECTIVE: To investigate the effects of the dosage of anticancer agents during transcatheter arterial chemoembolization (TACE) on the T cell subsets in patients with hepatocellular carcinoma (HCC). METHODS: Thirty-six patients with unresectable HCC were randomly divided into 2 groups to receive superselective TACE. Patients in group A (n=18) received low-dose (2-4 mg) mitomycin C (MMC) as the anticancer drug when the tumor was less than 5 cm in diameter; when the tumor ranged from 5 and 8 cm in diameter, 4-6 mg MMC along with 10 mg epirubicin (EPI) was given, and in cases of even larger tumors, 6-8 mg MMC, 10 mg EPI and 100 mg CBP were prescribed. Conventional chemotherapy regimen constituted by 10 mg MMC, 40 mg PI and 300 mg CBP was adopted in group B (n=18). The peripheral blood T cell subsets including CD3(+), CD4(+), CD8(+), NK, CD4(+)/CD8(+) ratio, CD4(+)CD45(+), CD4(+)CD29(+), CD8(+)CD28(+) and CD8(+)CD28- were measured by flow cytometry in both groups before and one week after treatment. RESULTS: The T cell subsets were comparable in the 2 groups before the treatment. After TACE, no significant changes occurred in CD3(+), CD4(+), CD8(+), NK, CD4(+)/CD8(+), CD4(+)CD29(+) or CD8(+)CD28- cells in group A, while significant decrease in CD4(+)CD45(+) and increase in CD8(+)CD28(+) cells were observed (P<0.05 and P<0.001, respectively). In group B, CD4(+) and CD4(+)CD29(+) levels, together with CD4(+)/CD8(+) ratio, were significantly lower than those before treatment (P<0.05), but CD8(+) and CD8(+)CD28- subsets were significantly higher (P<0.05). CONCLUSIONS: The cellular immune function of HCC patients is significantly impaired by anticancer drugs for TACE at conventional dose, while low-dose of the drugs may enhance the cellular immune function.

Adult↗