Biomedical subjects

Wei Lu

Publications and source records attributed to Wei Lu.

At least 145 records · Page 8Linked to original sources

PubMed2004

Dynamic in situ characterization of organic monolayer formation via a Novel substrate-mediated mechanism.

Ultrahigh vacuum scanning tunneling microscopy data investigating octylsilane (C8H17SiH3) monolayer pattern formation on Au(111) are presented. The irregular monolayer pattern exhibits a 60 A length scale. Formation of the octylsilane monolayer relaxes the Au(111) 23 x square root3 surface reconstruction and ejects surface Au atoms. Au adatom diffusion epitaxially extends the Au(111) crystal lattice via step edge growth and island formation. The chemisorbed monolayer covers the entire Au surface at saturation exposure. Theoretical and experimental data suggest the presence of two octylsilane molecular adsorption phases: an atop site yielding a pentacoordinate Si atom and a surface vacancy site yielding a tetracoordinate Si atom. Theoretical simulations investigating two-phase monolayer self-assembly dynamics on a solid surface suggest pattern formation results from strain-induced spinodal decomposition of the two adsorption phases. Collectively, the theoretical and experimental data indicate octylsilane monolayer pattern formation is a result of interfacial Au-Si interactions and the alkyl chains play a negligible role in the monolayer pattern formation mechanism.

Journal Article↗

PubMed2004

Significant changes of peripheral T lymphocyte subsets in patients with severe acute respiratory syndrome.

This report demonstrates that a rapid decrease of peripheral T cell subsets is a unique characteristic in patients with SARS during acute infection, although total white blood cell counts, red blood cell counts, and platelet counts remain relatively normal. In recovering patients, a rapid and dramatic restoration of peripheral T cell subsets was seen in the periphery. Although the underlying mechanism of the acute decrease of peripheral T cell subsets observed in patients with SARS during the acute stage remains unknown, this clinical characteristic can facilitate an earlier and more accurate diagnosis of SARS.

Antigens, CD↗

PubMed2004

cDNA cloning, genomic structure, chromosomal mapping, and expression analysis of parotid secretory protein in pig.

A novel cDNA has been isolated from pig parotid glands by 3' and 5' rapid amplification of cDNA ends and designated parotid secretory protein (PSP). The open reading frame of this cDNA covers 714 bases, encoding 238 amino acids, which show 56% identity with human PSP at the level of the primary protein structure. The PSP genomic sequence comprises eight exons and seven introns, is approximately 22 kb in size, determined by sequencing, and maps to pig chromosome 17q21-q23. RT-PCR, dot blot, and Northern blot analyses demonstrated that PSP is strongly expressed in parotid glands, but is not present in heart, liver, lung, kidney, muscle, or stomach. A search for functionally significant protein motifs revealed consensus sequences for casein kinase II phosphorylation and N-myristoylation. We observed a unique amino acid sequence pattern consisting of the residues Leu-X(6)-Leu-X(6)-Leu-X(7)-Leu-X(6)-Leu-X(6)-Leu near the amino-terminal portion of the protein, which is similar to the leucine zipper.

Amino Acid Sequence↗

PubMed2004

Interaction of hydrogen peroxide with ribulose-1,5-bisphosphate carboxylase/oxygenase from rice.

The properties of rice-derived ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) in different concentrations of hydrogen peroxide (H2O2) solutions have been studied. The results indicate that at low H2O2 concentrations (0.2-10 mM), the properties of rubisco (e.g., carboxylase activities, structure, and susceptibility to heat denaturation) change slightly. However, at higher H2O2 concentrations (10-200 mM), rubisco undergoes an unfolding process, including the loss of secondary and tertiary structure, forming extended hydrophobic interface, and leading to cross-links between large subunits. High concentrations of H2O2 can also result in an increase in susceptibility of rubisco to heat denaturation. Further pre-treatments with or without reductive reagents to rubisco show that the disulfide bonds in rubisco help to protect the enzyme from damage by H2O2 as well as other reactive oxygen species.

Circular Dichroism↗

PubMed2004

Pharmacokinetics of three organic nitrates in Chinese healthy male volunteers.

Eighteen Chinese male subjects completed a single-blind, randomized, three-treatment, three-period, cross-over study. In each treatment phase, subjects received a single dose of 20 mg isosorbide dinitrate (CAS 87-33-2, ISDN) intravenous infusion, 20 mg isosorbide 5-mononitrate (CAS 16051-77-7, 5-ISMN) tablet or 20 mg isosorbide 5-mononitrate intravenous infusion. Each consecutive dosing was separated by a washout period of 7 days. Following each dosing, venous blood samples were collected over a period of 16 h. Plasma concentrations of ISDN and its two active metabolites isosorbide 2-mononitrate (2-ISMN), 5-ISMN had been measured by a validated gas chromatographic method. Various pharmacokinetic parameters including AUC0-t, AUC0-infinity, Cmax, tmax, t1/2, Kelm and MRT were determined for the three formulations and found to be in good agreement with literature values. AUC0-t and AUC0-infinity of 5-ISMN tablet and intravenous infusion were 2694 +/- 496 ng x ml(-1) x h vs. 2548 +/- 556 ng x ml(-1) x h and 3266 +/- 624 ng x ml(-1) x h vs. 3178 +/- 769 ng x ml(-1) x h, respectively, and the relative bioavailability of 5-ISMN tablet was 105 +/- 20%. As compared with 5-ISMN intravenous infusion, ISDN can rapidly reach the plateau concentration and metabolize to its active metabolites 5-ISMN and 2-ISMN, which both have vasodilator effect. The results of this study suggest that as evaluated from the pharmacokinetic profiles of the three formulations, 5-ISMN tablet and ISDN intravenous infusion are ideal vasodilators and anti-angina drugs especially in acute conditions due to their rapid onset and long duration of action.

Administration, Oral↗

PubMed2004

Value of angiography in the diagnosis of patients with small kidney.

OBJECTIVE: To explore the diagnostic value of angiography in small kidney patients. METHODS: Angiographies were performed in 32 patients with small kidney of unknown etiology or with suspected renal arterial stenosis (RAS). RESULTS: Twelve cases of renal atrophy due to RAS were diagnosed by angiography, which demonstrated renal artery stenoses or occlusions. Angiography of 17 patients with nephrogenic renal atrophy displayed homogeneous shrinkage of the renal arteries except in the ostium. In 3 patients with renal hypoplasia, angiography showed narrowed renal arteries and tiny renal arterial branches. CONCLUSION: Renal artery angiography is of important values in the differential diagnosis between renal atrophy due to RAS, nephrogenic renal atrophy and non-renovascular renal atrophy, and renal hypoplasia.

Adult↗

PubMed2004

[Inhibition of anti-sense human telomerase reverse transcriptase (hTERT) retroviral vector on lung cancer cells].

BACKGROUND & OBJECTIVE: Inhibition of telomere length can be achieved through suppression of telomerase activity, which may result in the inhibition of immortal cell proliferation. In order to explore the possibility of the telomerase as a target for lung cancer therapy, we investigated the effects of anti-sense human telomerase reverse transcriptase (hTERT) on telomerase activity and cell proliferation of A549 lung cancer cell line. METHODS: The anti-sense hTERT cDNA, an 835 bp in the 5' region of hTERT mRNA was amplified by reverse transcription polymerase chain reaction (RT-PCR), before cloning into pLXSN retroviral vector in sense and anti-sense orientations. A549 cells, a human lung cancer cell line, were infected with recombinant virus obtained after transfection into packaging cell PT67. The expression of hTERT protein was determined by Western blot analysis. The telomerase activity was measured by telomerase repeat amplification protocol (TRAP). The cell proliferation was depicted by cell morphology under inverted microscopy as well as cell growth curve. Apoptosis was analyzed by flow cytometry and DNA electrophoresis. RESULTS: Compared with sense hTERT transduction, hTERT expression and telomerase activity significantly decreased in A549 cells after anti-sense hTERT transduction. The cell proliferation was markedly inhibited with evidence of apoptosis. CONCLUSION: Anti-sense hTERT exhibited significant inhibition of telomerase activity and cell proliferation, in addition to acceleration of apoptosis. This implied the possibility of hTERT as the potential target for gene therapy of lung cancer.

Adenocarcinoma↗

PubMed2004

[Epidemiological study on traffic accident in Shanghai from 2000 to 2002].

OBJECTIVE: Data on traffic accident from year 2000 to 2002 were collected and testified. Epidemiological study was carried out to find the main risk factors of traffic accident. METHODS: The spatial distribution was conducted by means of Geographic Information System (GIS) and were marked on Shanghai digitalized map with different layers by different colors. RESULTS: Results showed that during 2000, 2001 and 2002, 69,669 , 68,894, and 47,088 traffic accident episodes occurred in Shanghai, resulting in 1747, 1724, 1557 deaths respectively with direct economic lost: 2.1, 2.4, 3.0 billion RMB. The main risk factors causing traffic accident deaths would include drinking alcohol before driving, fatigue and speeding. The leading causes of death were head injury and complex injury of body. GIS showed that there was a homocentric circle with more traffic accidents in downtown city, but more deaths in the urban city. Disease burden caused by traffic accident was very heavy. CONCLUSION: In Shanghai, traffic accident has great impact on social and economic issues thus should be controlled effectively. Focus should be layed on control of traffic accident in downtown area and to decrease the number of deaths related to traffic accident in the urban area.

Accidents, Traffic↗

PubMed2004

[Clinical analysis of 50 cases of cytomegalovirus disease].

OBJECTIVES: To investigate the clinical features, diagnostic methods, therapeutic approaches, outcomes and the alterations of peripheral lymphocyte subsets in cytomegalovirus (CMV) diseases. METHODS: From August 2000 to October 2002, 50 cases of CMV diseases were treated in Peking Union Medical College Hospital. The diagnosis were made by their symptoms and positive CMV pp65 antigen or/and CMV specific IgM. Of the 50 patients, 15 were male, and 35 female. Their age was (35.5 +/- 16.2) years. Their clinical data were collected, and their peripheral lymphocyte subsets were measured at the time when they were first diagnosed as CMV disease. The lymphocyte subsets of 51 healthy blood donors were tested as normal controls. The lymphocyte subsets were compared between those who had an immunocompromising underlying disease and those who had not. RESULTS: (1) CMV disease occurred in 39 patients who had immunocompromising underlying diseases, and in 11 patients who had not; (2) CMV disease caused various symptoms, most of them were nonspecific. Fever (100%), hematological abnormalities (96%) and abnormal liver function test (30%) were the most common manifestations. 3 cases of CMV retinitis were acquired immune deficiency syndrome patients with CD4+ T cell count less than 50/ microl; 2 patients developed multiple organ failure; (3) The positive rates of CMV pp65 antigen and specific IgM assays were 85.3% and 68.3%, respectively; (4) Comparing with normal controls, all patients with CMV disease had decreased B cell and nature killer cells, increased CD8+ T cell percentage and a reversed CD4+/CD8+ ratio; further more, the patients with underlying diseases had lower CD4+ T-cell and CD8+ T-cell counts than those without underlying diseases. CONCLUSIONS: CMV disease occurred in patients with or without underlying diseases. Their clinical manifestations were heterogeneous and non-specific, therefore, special laboratory tests were necessary to confirm the diagnosis. pp65 antigen assay had more diagnostic value than IgM assay. The dramatic changes in lymphocyte subsets suggest CMV disease has a immunological pathogenesis.

Adolescent↗

PubMed2004

[Methods of enumeration of bacteria in drinking water].

Methods of the enumeration of total bacteria and Coliform in drinking water were researched in this paper. The differences between heterotrophic plate count and direct viable count method were compared. It is concluded that the total number of bacteria in R2A medium is one order of quantity higher than the traditional plate count agar, and the results of acridine orange direct counts (AODC) is the highest. Some different staining methods in direct viable count were also compared in this paper, such as nalidixic acid, CTC staining and BacLight staining. The proportion of the live bacteria to the dead is about 10%.

Bacteria↗

PubMed2004

Sustained-release hydroxycamptothecin polybutylcyanoacrylate nanoparticles as a liver targeting drug delivery system.

Sustained release hydroxycamptothecin polybutylcyanoacrylate nanoparticles (HCPT-PBCA-NP) associated with polybutylpyrolidone (PVP) for liver targeting were prepared by the adsorption-entrapping method. The morphology, sizes, drug loading efficiencies, release characteristics in vitro, distribution and pharmacokinetic parameters in vivo of the HCPT-PBCA-NP associated with PVP were studied. The median diameter of the particles was 81 nm and the drug loading was 1.2%. The release characteristics in vitro were in accordance with the Higuchi equation: Q = 0.0615 + 0.0940 mean square root t. 64.5% of the HCPT were concentrated in the liver at 15 min after i.v. administration of HCPT-PBCA-NP associated with PVP. The plasma drug concentration-time curve of the HCPT in rabbits was fitted to a two-compartment open model. The Vc, T 1/2 and CL were 3.5L; 147h; 0.18L x h(-1), respectively. The method of preparation presented in this paper seems to bean alternative for the preparation of PBCA-NP of poorly soluble drugs both in water and in lipid.

Animals↗

PubMed2004

[Study on space flight-mutants of Monascus purpureus using Random Amplified Polymorphic DNA].

OBJECTIVE: To study the mechanism of microbial mutation in aerospace. METHOD: Random Amplified Polymorphic DNA (RAPD) was used to analyze the polymorphism of high Lovastatin-producing mutants. RESULT: Variations occurred in genomes of these mutants. CONCLUSION: The high Lovastatin producibility of the mutants is due to the variation of genomes, therefore the microbial mutation in the aerospace is achieved via the variation of hereditary genes in the microbes.

DNA, Fungal↗

PubMed2004

[Randomized control study on domestic fixed-dose combinations in the initial treatment of smears positive tuberculosis].

OBJECTIVE: To explore the feasibility of domestic fixed-dose combinations as antituberculosis therapy applied in the National Tuberculosis Program. METHODS: A randomized control trial was conducted and 422 smear-positive pulmonary tuberculosis patients were randomly distributed into 2 groups. The trial group was treated daily with rifampicin, isoniazid and pyrazinamide tablets (including 120 mg rifampicin, 80 mg isoniazid and 250 mg pyrazinamide) in the first 2 months and rifampicin and isoniazid tables (including 300 mg rifampicin, 150 mg isoniazid) in the subsequent 4 months. The control group was treated by full 6-month standard regimens (2HRZE/4H3R3). RESULTS: The demographic data and the disease status were similar between the 2 groups before treatment. The rate of conversion from positive to negative cases in the trial group after therapy was 91.6% at 2 months, 97.2% at 3 months, and 97.7% at 6 months, while that of the control group was 87.3%, 97.5%, and 98.0% respectively. The difference in the conversion rates between the two groups was not statistically significant (chi2 = 2. 05, chi2 = 0.03, chi2 = 0.04, P > 0.05). The incidence of skin rash as an adverse effect was less common in the trial group as compared to the control group (Fisher's exact P = 0.024 33) . CONCLUSIONS: Domestic fixed-dose combinations as supplementary anti-tuberculous therapy could be used in the National Tuberculosis Program, but further study is needed for widespread application.

Adolescent↗

PubMed2003

Polymorphic forms of a gold(I) arylacetylide complex with contrasting phosphorescent characteristics.

The spectroscopic properties and crystal structures of the gold(I) arylacetylide complexes [(R(3)P)Au(Ctbd1;CAr)] (R = Cy, Ar = 4-nitrophenyl, 1; 4-trifluoromethylphenyl, 2; pentafluorophenyl, 3; R = Ph, Ar = 4-nitrophenyl, 4) have been examined. The dipole-allowed and -forbidden transitions of 1 (4 in parentheses) at lambda(max) 340 (336) and ca. 485 (470) nm in CH(2)Cl(2) solution at 298 K are assigned to the singlet and triplet intraligand charge transfer (ILCT) transitions of the 4-nitrophenylacetylide moiety, whereas 2 (3 in parentheses) shows localized singlet and triplet acetylenic pipi transitions at lambda(max) 287 (276) and 426 nm, respectively. Two polymorphs of 1 with contrasting phosphorescent characteristics have been identified. At 298 K, the emissive form of 1, as well as 2-4, are highly phosphorescent with peak maximum at 504, 425, 521, and 495 nm, respectively; the other polymorph of 1 is nonemissive at 298 K but emission is detected at 77 K with peak maximum at 486 nm. Crystallographic studies reveal that the major differences between the emissive and nonemissive forms of 1 are the orientations of the molecular dipoles and the dihedral angles between neighboring 4-nitrophenyl moieties. Crystal 2 is isostructural to the nonemissive form of 1, but does not display polymorphism. The molecular planes of two neighboring lumophores are coplanar in the emissive form of 1, parallel in 4, and nearly perpendicular (78.6 degrees ) to each other in the nonemissive form of 1. Both the nature of the excited state and the dihedral angle between adjacent [Au(Ctbd1;CAr)] moieties determine the phosphorescent properties of these molecular crystals.

Journal Article↗

PubMed2003

Structural basis for vapoluminescent organoplatinum materials derived from noncovalent interactions as recognition components.

The spectroscopic properties and crystal structures of a series of platinum(II) complexes bearing functionalized sigma-alkynyl groups, namely [(tBu(2)bpy)Pt(C triple bond CAr)(2)] (tBu(2)bpy = 4,4'-bis-tert-butyl-2,2'-bipyridine, Ar = 4-pyridyl, 1; 3-pyridyl, 2; 2-pyridyl, 3; 4-ethynylpyridyl, 4; 2-thienyl, 5; pentafluorophenyl, 6) have been studied. Solid-state emissions of 1 and 6 are dependent on their crystallinity. Reversible and selective vapoluminescence was observed for 1 and 6 in the presence of chlorocarbon vapors. For solid 1, dramatic enhancement of green luminescence is observed upon sorption of CH(2)Cl(2) or CHCl(3) vapor. The excimeric orange emission for solid 6 is switched to monomeric green emission upon exposure to CH(2)Cl(2) vapor. The luminescent responses of a thin film of 1 towards various organic vapors have also been examined. In the crystallographically determined structure of 1.CH(2)Cl(2), the bis(acetylide) moiety acts as the receptor berth for a CH(2)Cl(2) molecule through concerted C-H.pi(C triple bond C) interactions, while Cl.Cl interactions connect the CH(2)Cl(2) molecules into infinite linear chains. The observed crystal lattices are arranged into scaffolds of varying porosity by weak C-H...N(py) (1.CH(2)Cl(2), 1.CH(3)CN, 4.DMF) and C-H...F-C (6, 6.CH(3)CN) interactions. The correlation between the crystal structures of 1.CH(2)Cl(2), 1.CH(3)CN, 2, 4.DMF, 5, 6, and 6.CH(3)CN and their vapoluminescence suggests that weak nonconventional hydrogen-bonding interactions preside over the reversible sensing and signalling processes.

Journal Article↗

PubMed2003

Ser217Leu polymorphism of the HPC2/ELAC2 gene associated with prostatic cancer risk in Japanese men.

The HPC2/ELAC2 gene may be associated with hereditary/familial prostate cancer (PCa). Two common missense variants (Ser217Leu and Ala541Thr) have been reported in the gene. We performed mutational, allelotyping and expression analyses and a molecular epidemiological study to clarify the relations between this gene and prostatic diseases, including PCa and benign prostatic hyperplasia (BPH) in Japanese men. We screened for mutations in 109 patients with PCa including 11 patients from 1 hereditary and 9 familial PCa. Loss of heterozygosity and expression were analyzed. An epidemiological study was done in sporadic PCa (n=98) and BPH (n=143) using 1 novel (Ser627Leu) and 2 previously described polymorphisms of the HPC2/ELAC2 gene. Somatic or germline mutations were not confirmed in any cases of PCa. Loss of heterozygosity at 2 microsatellites, D17S1289 and D17S520, was detected in 1 of 38 and 1 of 35 cases, respectively. Expression analysis revealed decreased or absent mRNA expression in 6 of 38 tumors. Epidemiologic analysis showed that a Leu allele at codon 217 was significantly more frequent in patients with PCa than in controls (10.2% vs. 3.5%, odds ratio = 3.11; 95% confidence interval, 1.22-7.90). At codon 541, all patients with PCa or BPH and all control subjects had the Ala/Ala genotype. At codon 627, the incidence of the Leu variant was slightly, but not significantly, higher in patients with BPH than in controls (7.0% vs. 2.8%, odds ratio = 2.59, 95% confidence interval, 0.94-7.13, not statistically significant). We concluded that germline/somatic mutations of HPC2/ELAC2 are uncommon in PCa. Similarly, allelic imbalances at the gene locus and changes in expression are rare. Although no difference in allele frequency at Ser217Leu between patients with PCa and controls has been reported in a Western population, this polymorphism is a potential indicator of PCa risk in Japanese men and it should be examined in other ethnic groups.

Aged↗

PubMed2003

T cell survival/proliferation reconstitution by trifluoperazine in human immunodeficiency virus-1 infection.

Recent findings support an indirect relationship between T cell depletion in HIV-1 infection and the rate of virus replication with implications for treatment strategies. We have initiated a new approach to recover immune function through the use of novel chemical agents. A cationic amphiphilic drug that binds to Ca(2+)-calmodulin at high concentrations, [10-[3-(4-methyl-1-piperazinyl)-propyl]-2- (trifluoromethyl)-(10)H-phenothiazine dihydrochloride] [denoted trifluroperazine dihydrochloride (Tfp); molecular weight 480.43] TFP was found at low concentrations (10(-6) to 10(-10) M) to help T cells from AIDS patients to restore proliferation in vitro. Here we show that the Tfp molecule can restore the cell survival of T lymphocytes from PBMCs derived from HIV-1-infected patients in vitro. Tfp enhances T cell proliferation and Th-cell responses by selectively inhibiting cell mortality and apoptosis. The restored antigen-specific response is associated with the synthesis of IL-2 and gamma-interferon. Even though this drug does not possess any detectable antiviral effect, it might be considered as a potential therapeutic agent in HIV-infected patients, to correct immune defects. Besides antiviral compounds, these data may facilitate immune reconstitution in patients with HIV infection and other immunosuppressive diseases.

Apoptosis↗

PubMed2003

Profiles of methotrexate in blood and CSF following intranasal and intravenous administration to rats.

The aim of this paper was to investigate the levels of methotrexate (MTX) in blood and the cerebrospinal fluid (CSF) in rats to find out whether there is any direct drug transport from nasal cavity to CSF following intranasal administration. Methotrexate was administered to male Sprague-Dawley rats either intranasally or intravenously. Drug concentrations were determined from CSF and plasma samples collected from the cisterna magna and caudal vein, respectively. To collect CSF sample continuously, blank artificial CSF was infused into the lateral ventricle. The plasma levels achieved following intranasal administration were significantly lower than those after intravenous administration (P<0.01) were, while CSF concentrations achieved after intranasal administration were significantly higher than those after intravenous administration (P<0.01). The ratio of the AUC(CSF) value between the intranasal route and the intravenous injection was 13.76, whereas the absolute bioavailability was only 6.3%, the drug targeting index (DTI) of nasal route was 21.7. In conclusion, these results showed that the antineoplastic MTX must be directly transported from the nasal cavity into the CSF in rats.

Administration, Intranasal↗