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Biomedical subjects

Qian Peng

Publications and source records attributed to Qian Peng.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Value of serum soluble interleukin-2R, interleukin-6 and C-reactive protein in the early diagnosis of Kawasaki disease].

OBJECTIVE: Immunovasculitis is a pathologic process of Kawasaki disease (KD) in the early stage and it is more likely to result from abnormal immunoactivation. It is thus speculated that the serum levels of some cytokines have changed before immunovasculitis occurs, suggesting the cytokines may be useful markers for the early diagnosis of KD. In this study, we measured the serum levels of soluble interleukin-2 receptors (sIL-2R), interleukin-6(IL-6) and high-sensitive C-reactive protein (hs-CRP) in patients with KD to evaluate the significance of these cytokines in the early diagnosis of KD. METHODS: Serum levels of sIL-2R and IL-6 were measured by rapid one-step sandwich enzyme immunoassay and the serum hs-CRP level was measured by Dade Behring BN ProSpec in 32 KD patients before and after intravenous immunoglobulin (IVIG) therapy. Twenty healthy children were used as the controls. RESULTS: Before IVIG therapy serum levels of sIL-2R (9253.41 +/- 2568.38 pg/mL vs 2161.53 +/- 696.92 pg/mL; P < 0.05), IL-6 (57.19 +/- 45.78 ng/mL vs 7.04 +/- 1.69 ng/mL; P < 0.05) and hs-CRP (117.69 +/- 42.05 mg/L vs 1.15 +/- 0.54 mg/L; P < 0.05) in KD patients were significantly higher than those in healthy controls. After IVIG therapy in KD patients serum IL-6 levels returned to normal and sIL-2R and hs-CRP levels decreased significantly but remained significantly higher than controls (P < 0.05). There was a positive correlation between sIL-2R and hs-CRP levels (r=0.60, P < 0.01). IL-6 levels positively correlated with hs-CRP levels in KD patients before IVIG therapy (r=0.68, P < 0.01). CONCLUSIONS: IL-2R, IL-6 and hs-CRP are activated in the development of KD, and they may be of important value in the early diagnosis of KD.

C-Reactive Protein↗
PubMed2005

Highly sensitive spectrofluorimetric determination of trace amounts NADP using Europium ion-doxycycline complex probe.

A new spectrofluorimetric method was developed for determination of trace amount of Coenzyme II (NADP). Using europium ion-doxycycline (DC) as a fluorescent probe, in the buffer solution of pH 8.44, NADP can remarkably enhance the fluorescence intensity of the Eu(3+)-DC complex at lambda=612 nm and the enhanced fluorescence intensity is in proportion to the concentration of NADP. Optimum conditions for the determination of NADP were also investigated. The dynamic range for the determination of NADP is 3.3 x 10(-7) to 6.1 x 10(-6) mol l(-1) with detection limit of 6.8 x 10(-8) mol l(-1). This method is simple, practical and relatively free interference from coexisting substances and can be successfully applied to determination of NADP in synthetic water samples and in serum samples. Moreover, the enhancement mechanisms of the fluorescence intensity in the Eu(3+)-DC system and the Eu(3+)-DC-NADP system have been also discussed.

Doxycycline↗
PubMed2005

Targeting PBR by hexaminolevulinate-mediated photodynamic therapy induces apoptosis through translocation of apoptosis-inducing factor in human leukemia cells.

Photodynamic therapy (PDT) with endogenous protoporphyrin IX derived from 5-aminolevulinic acid or its derivatives has been established for treatments of several premalignancies and malignancies; however, the mechanism of the modality is not fully elucidated. The mitochondrial permeability transition pore consists mainly of the mitochondrial outer membrane voltage-dependent anion channel and the peripheral benzodiazepine receptor (PBR) and the mitochondrial inner membrane adenine nucleotide translocator (ANT). These mitochondrial proteins are responsible for the permeability transition that leads to apoptosis. In the present study, the human leukemia cell line, Reh, was treated with PDT using hexaminolevulinate (HAL). More than 80% of apoptotic Reh cells were found after HAL-mediated PDT (HAL-PDT) with high-molecular-weight (50 kbp) DNA fragmentation. Addition of PK11195 or Ro5-4864, two ligands of PBR, during HAL-PDT significantly inhibited the apoptotic effect. Bongkrekic acid, a ligand for ANT, also reduced the PDT effect. Although the mitochondrial transmembrane potential collapsed, neither cytosolic translocation of mitochondrial cytochrome c nor activation of caspase-9, caspase-8, caspase-3, and poly(ADP-ribose) polymerase were found. However, nuclear translocation of mitochondrial apoptosis-inducing factor (AIF) was shown by both immunoblotting and immunocytochemistry. Because AIF is the sole one among all proapoptotic factors involved in caspase-dependent and caspase-independent pathways that induces the high-molecular-weight DNA fragmentation, we conclude that HAL-PDT specifically targets PBR, leading to apoptosis of the Reh cells through nuclear translocation of mitochondrial AIF. This study suggests PBR as a possible novel therapeutic target for HAL-based PDT of cancer.

Aminolevulinic Acid↗
PubMed2005

Synthesis of linked berberine dimers and their remarkably enhanced DNA-binding affinities.

This communication describes the facile synthesis of five novel berberine dimers and their strong affinities toward double-stranded DNA. These berberine dimers were synthesized in 37-84% yields from the reaction of berberrubine with dihaloalkanes of varying lengths, and fully characterized by HRMS and 1H NMR. Compared with the monomeric parent berberine, these dimers showed greatly enhanced binding affinities up to approximately 100-fold, with two double helical oligodeoxynucleotides, d(AAGAATTCTT)2 and d(TAAGAATTCTTA)2, which was investigated by means of fluorescence spectrometry.

Base Sequence↗
PubMed2005

Structures, electronic states, photoluminescence, and carrier transport properties of 1,1-disubstituted 2,3,4,5-tetraphenylsiloles.

The excellent electroluminescent (EL) properties of 1,1-disubstituted 2,3,4,5-tetraphenylsiloles, 1-methyl-1,2,3,4,5-pentaphenylsilole (MPPS), and 1,1,2,3,4,5-hexaphenylsilole (HPS) have been found. Despite some studies devoted to these materials, very little is known about the real origin of their unique EL properties. Therefore, we investigated the structures, photoluminescence (PL), and charge carrier transport properties of 1,1-disubstituted 2,3,4,5-tetraphenylsiloles as well as the effect of substituents on these characteristics. The single crystals of the three siloles involving 1,1-dimethyl-2,3,4,5-tetraphenylsilole (DMTPS), MPPS, and HPS were grown and their crystal structures were determined by X-ray diffraction. Three siloles have nonplanar molecular structures. The substituents at 1,1-positions enhance the steric hindrance and have predominant influence on the twisted degree of phenyl groups at ring carbons. This nonplanar structure reduces the intermolecular interaction and the likelihood of excimer formation, and increases PL efficiency in the solid state. The silole films show high fluorescence quantum yields (75-85%), whereas their dilute solutions exhibit a faint emission. The electronic structures of the three siloles were investigated using quantum chemical calculations. The highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) are mainly localized on the silole ring and two phenyl groups at 2,5-positions in all cases, while the LUMOs have a significant orbital density at two exocyclic Si-C bonds. The extremely theoretical studies of luminescent properties were carried out. We calculated the nonradiative decay rate of the first excited state as well as the radiative one. It is found that the faint emission of DMTPS in solutions mainly results from the huge nonradiative decay rate. In solid states, molecular packing can remarkably restrict the intramolecular rotation of the peripheral side phenyl ring, which has a large contribution to the nonradiative transition process. This explains why the 1,1-disubstituted 2,3,4,5-tetraphenylsiloles in the thin films exhibit high fluorescence quantum yields. The charge carrier mobilities of the MPPS and HPS films were measured using a transient EL technique. We obtained a mobility of 2.1 x 10(-)(6) cm(2)/V.s in the MPPS film at an electric field of 1.2 x 10(6) V/cm. This mobility is comparable to that of Alq(3), which is one of the most extensively used electron transport materials in organic light-emitting diodes (LEDs), at the same electric field. The electron mobility of the HPS film is about approximately 1.5 times higher than that of the MPPS film. To the best of our knowledge, this kind of material is one of the most excellent emissive materials that possess both high charge carrier mobility and high PL efficiency in the solid states simultaneously. The excellent EL performances of MPPS and HPS are presumably ascribed to these characteristics.

Journal Article↗
PubMed2005

Phylogenetic analysis of several Thermus strains from Rehai of Tengchong, Yunnan, China.

Several Thermus strains were isolated from 10 hot springs of the Rehai geothermal area in Tengchong, Yunnan province. The diversity of Thermus strains was examined by sequencing the 16S rRNA genes and comparing their sequences. Phylogenetic analysis showed that the 16S rDNA sequences from the Rehai geothermal isolates form four branches in the phylogenetic tree and had greater than 95.9% similarity in the phylogroup. Secondary structure comparison also indicated that the 16S rRNA from the Rehai geothermal isolates have unique secondary structure characteristics in helix 6, helix 9, and helix 10 (reference to Escherichia coli). This research is the first attempt to reveal the diversity of Thermus strains that are distributed in the Rehai geothermal area.

Base Sequence↗
PubMed2005

[Clinical value of serum matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 for the prediction and early diagnosis of coronary artery lesion in patients with Kawasaki disease].

OBJECTIVE: Kawasaki disease (KD) complicated with coronary artery lesion (CAL) seriously threatens survival quality and life of patients, suggesting that it is very important to early predict the risk of CAL and to early diagnose the disease. Nevertheless, up to now there has been no specific clinical biochemical marker for it because of the poor understanding of the pathological process of KD with CAL. Matrix metalloproteinases (MMPs) and their specific tissue inhibitor of metalloproteinases (TIMPs) play an important role in arterial wall extracellular matrix breakdown and remodeling and are involved in CAL in other diseases. In the present study the practical value of serum MMP-9 and TIMP-1 levels in the prediction and early diagnosis of CAL in KD patients was investigated. METHODS: All subjects were from Chinese population. Serum levels of MMP-9 and TIMP-1 were measured by rapid one-step sandwich enzyme immunoassay in 59 KD patients including 15 with CAL and 44 without CAL by 2 D-echocardiography and coronary angiography, and 20 normal healthy children as controls. Blood samples of patients were obtained before and after intravenous immunoglobulin (IVIG) treatment in acute stage, subacute stage and convalescent stage as well. Serum MMP-9 and TIMP-1 levels and the ratio of MMP-9/TIMP-1 were compared by statistical method in KD patients and controls, as well as in KD with CAL and without CAL. RESULTS: In acute stage serum MMP-9 and TIMP-1 levels and the ratio of MMP-9/TIMP-1 were higher (P < 0.01) in patients with KD than those in healthy children. After IVIG treatment in KD patients serum MMP-9 level and the ratio of MMP-9/TIMP-1 decreased (P < 0.01). Before IVIG treatment serum MMP-9 level and the ratio of MMP-9/TIMP-1 were higher (P < 0.01) in patients with CAL than those in patients without CAL, and in acute stage after IVIG treatment serum MMP-9 level of KD patients with CAL was still higher than that of KD patients without CAL. CONCLUSION: In acute stage of KD serum MMP-9 level and the ratio of MMP-9/TIMP-1 were higher in patients with CAL than those in patients without CAL, suggesting that during acute phase of KD the great increase in serum MMP-9 and the imbalance of the MMP-9/TIMP-1 ratio might be high risk factors of KD coronary artery lesion. Therefore, the measurement of serum MMP-9 and TIMP-1 might be of important clinical value in the prediction and the early diagnosis of KD with coronary artery lesion.

Biomarkers↗
PubMed2004

On the interconversion pathway of HBO<-->BOH.

The potential energy surfaces have been constructed for the 1A', 3A', and 3A" states of HBO by using the multireference perturbation theory with the basis set cc-pVTZ (6d,10f). Two stationary points and a transition state have been characterized on all the three surfaces, which are in good agreement with available experiments and previous calculations. The interconversion pathways from metastable boron hydroxide BOH to the considerably more stable HBO are expounded based on the nature of the surfaces.

Journal Article↗
PubMed2004

[Analysis of bacterial composition of the pink mat from spectacles hot spring in Tengchong by culture-independent approach].

The bacterial composition of the pink mat was studied by culture-independent approach. 23 complete 16S rDNA sequences were obtained. According to the sequences alignment and analysis of comparability, the bacteria of the pink mat was consisted of Proteobacteria, Firmicutes, Bacteroidetes, Actinobacter, Deinococcus-thermus, Aquificals. And compared with bacterial composition of the mats from Octopus spring in Yellowstone Park and Haegindi and Fluidir spring, Olkelduhals, Grensdalur spring in Iceland, the pink mat in spectacles spring had highest bacterial diversity among them because it perhaps included lots of bacteria at lower temperature. And the result indicated the same community lived in the same niche and Aquficales was dominant group among bacterial composition of the mat in higher temperature and near-neutral hot spring.

Bacteria↗
PubMed2003

Pharmacology of protoporphyrin IX in nude mice after application of ALA and ALA esters.

Aminolevulinic acid (ALA), ALA methylester (ALA-Me) and ALA hexylester (ALA-Hex) were topically applied for 5 and 20 hr, respectively, on normal skin of mice. The distribution of protoporphyrin IX (PpIX) induced in 7 different tissues by these drugs was determined either by spectrofluorometric measurements with an optical fibre probe or by chemical extraction of PpIX from the tissues. The results from these 2 types of measurements were compared. Both methods showed that ALA and the esters induced similar amounts of PpIX at the skin spot where they were applied and that the esters produced much less PpIX at remote skin spots (i.e., spots outside the location where the drugs were applied) than ALA did, notably after 20 hr application. After 20 hr of drug application ALA produced much more PpIX in liver, intestine and lungs than the esters did. In contrast with the direct fluorescence measurements, the extraction method showed detectable amounts of PpIX in liver, intestine and lung after application of the esters, notably of ALA-Me. The discrepancy is probably related to the fact that the pigmented tissues absorb light and, therefore, the direct fluorescence readings are misleading. Notably in the liver, which contains high concentration of light-absorbing pigments, very weak direct fluorescence was seen. In no case there was any accumulation of PpIX in muscle tissue nor in brain. The esters seem to penetrate less into the circulation than ALA, and PpIX formed by them in the skin is faster cleared than PpIX formed from ALA. This is also true after oral and i.p. administration of the drugs.

Administration, Topical↗
PubMed2003

[Preliminary study on bacterial diversity in a hot spring by using culture-independent approach].

Bacterial biodiversity of the hot spring Dagunguo in Tengchong Rehai in Yunnan Province, China was preliminarily studied with culture-independent method. Five complete 16S rDNA sequences were obtained and phylogenetically analysed. Four of these sequences were closely related to the genera: Bacillus, Hydrogenobacter and Pseudomonas, and the other one was clustered with the Family Thermodesulfobacteriaceae between an unpublished genus Geothermobacterium and Thermodesulfobacteria. The V8 high variable region(about 600bp) of 16S rDNA from the five 16S rDNA sequences and the genomic DNA were obtained by PCR. All of the PCR products were run DGGE. The pattern of DGGE and the phylogenetic tree of the five sequences not only indicated the hot spring Dagunguo of Yunnan province has plenty of bacterial species but also showed they were dominant bacterial species in the hot spring.

Bacteria↗
PubMed2002

Meiothermus rosaceus sp nov isolated from Tengchong hot spring in Yunnan, China.

A rosy-pigmented Gram-negative, thermophilic bacterium with an optimum growth temperature of about 55 degrees C was isolated from Tengchong hot springs in Yunnan province, China. Its growth scarcely occurred below 40 degrees C or above 70 degrees C. Phylogenetic and secondary structural analyses of 16S rRNA and DNA-DNA hybridization showed that the organism represented a new species of the genus Meiothermus. This new species could be distinguished easily from other species of the genus Meiothermus by the following phenotypic characteristics: rosy pigment, expanded body, sucrose and maltose were not utilized, gelatin and starch were not hydrolyzed. On the basis of the above data, the name Meiothermus rosaceus sp. nov. was proposed for the species represented by the strain RH9901(T)(CCTCC-AB200291).

Base Composition↗
PubMed2002

Thermus rehai sp. nov., isolated from Rehai of Tengchong, Yunnan Province, China.

A yellow-pigmented strain of the genus Thermus, with optimum growth temperatures about 65 approximately 70 degrees C, was isolated from the hot springs in Rehai of Tengchong, Yunnan Province, China. Morphological, physiological and biochemical characteristics, pigment analysis of RH99-GF7504 strain and its phylogenetic analysis of 16S rDNA showed that this organism represented a new species of the genus Thermus. This strain had maximum temperatures for growth below 80 degrees C. The new isolate from Rehai of Tengchong could be distinguished from other strains of the genus Thermus by its special structure and by its inability to hydrolyze gelatin and starch. On the basis of phylogenetic analysis, morphological, physiological and biochemical characteristics, the name Thermus rehai sp nov is proposed for the species, represented by strain RH99-GF7504 (CCTCC-AB200292).

China↗
PubMed2002

The stability of 5-aminolevulinic acid in solution.

5-Aminolevulinic acid (ALA) is being assessed for photodynamic therapy of cancer and other diseases worldwide. However, its stability properties in solution are not well understood yet. The breakdown of ALA in pH-buffered solutions was examined in this work. Solutions of ALA in PBS buffered to physiological pH were found to be unstable, leading to a breakdown product that absorbs photons around 278 nm. The ability of the solution to stimulate porphyrin production in cells is gradually lost upon breakdown, though the kinetics for this are different from those for formation of the UV absorbing product. It is likely, therefore, that several chemical pathways contribute to the breakdown of dissolved ALA at physiological pH. Temperature studies of the formation kinetics of the UV absorbing product also indicate that a complex formation process is involved.

Aminolevulinic Acid↗
PubMed2002

5-Aminolevulinic acid-based photodynamic detection and therapy of brain tumors (review).

With current treatment methods the prognosis for patients with aggressive brain tumors is dismal. Treatment failure is usually due to local recurrence of tumor. Intra-operative photodynamic detection (PDD) of tumor tissue and post-surgical photodynamic therapy (PDT) of the resection cavity may be of benefit. The utility of 5-aminolevulinic acid (ALA) has been recognized in many different treatment fields over the past decade. Following administration of exogenous ALA, the endogenous photosensitizer, protoporphyrin IX (PpIX), accumulates in tumor tissue. A photodynamic effect occurs upon light activation of the target tissue. This article reviews the current preclinical and clinical studies and potential future applications of ALA and its ester-induced PpIX as a photosensitizing agent in the detection and treatment of brain tumors.

Aminolevulinic Acid↗
PubMed2002

Comparison of 5-aminolevulinic acid and its hexylester mediated photodynamic action on human hepatoma cells.

5-Aminolevulinic acid (ALA) is a precursor to heme synthesis pathway and currently used to induce endogenous protoporphyrin IX (PpIX, a potent photosensitizer) for photodynamic therapy of cancer. ALA has, however, a limited ability to cross cellular membranes due to its low lipid solubility. The use of lipophilic ALA esters may increase cellular uptake, which results in an enhanced PpIX synthesis. In the present study, a comparison of ALA and its hexyl ester (He-ALA) was made in the QGY human hepatoma cell line with respect to PpIX production and its photocytotoxicity. The fluorescence emission spectrum of the cells incubated with He-ALA was identical to that of PpIX, indicating that He-ALA could induce PpIX in the cells. Fluorescence images demonstrated that the He-ALA induced PpIX was localized in the cytoplasm of the cells. Moreover, a similar amount of Pp IX was found in the cells incubated with 0.2 mmol/L He-ALA or 2 mmol/L ALA and a similar level of cell survival was reached following light exposure. These results suggest that He-ALA is much more efficient at producing PpIX and photocytotoxicity than ALA itself in the cells.

Aminolevulinic Acid↗
PubMedDate not supplied

Effects of photodynamic therapy on tumor stroma.

Photodynamic therapy (PDT) is a treatment that combines a photosensitizer with light to generate oxygen-dependent photochemical destruction of diseased tissue. This modality has been approved worldwide since 1993 for the treatment of several oncological and nononcological disorders. PDT continues to be interested in both preclinical and clinical research, with more than 500 publications each year during the past 5 years. This minireview focuses on the effects of PDT on tumor stroma. A tumor consists of two fundamental elements: parenchyma (neoplastic cells) and stroma. The stroma is composed of vasculature, cellular components, and intercellular matrix and is necessary for tumor growth. All the stromal components can be targeted by PDT. Although the exact mechanism of PDT is unknown, emerging evidence has indicated that effective PDT of tumor requires destruction of both parenchyma and stroma. Further, damage to subendothelial zone of vasculature, in addition to endothelium, also appears to be a crucial factor. The PDT-generated immune response as a way of vaccination for treatment and prevention of metastatic tumors remains to be exploited.

Endothelium, Vascular↗