Biomedical subjects

Min Yang

Publications and source records attributed to Min Yang.

At least 37 records · Page 2Linked to original sources

PubMed2006

CART peptide promotes the survival of hippocampal neurons by upregulating brain-derived neurotrophic factor.

The neuropeptide cocaine- and amphetamine-regulated transcript (CARTp) plays a role in various physiological processes. CARTp is highly expressed in rat hippocampus and can promote the survival and differentiation of neurons in primary hippocampal cell cultures. However, little is known about the neurotrophic mechanism of CARTp on the hippocampal neuron. We show that CARTp fragment 55-102 promoted the survival of cultured hippocampal neurons by increasing the number of surviving neurons and their viability. The tyrosine kinase B (TrkB) antibody, known to inhibit the activity of brain-derived neurotrophic factor (BDNF), blocked the survival-promoting effect of CARTp on hippocampal neurons. Further study by reverse-transcription PCR showed that BDNF mRNA expression significantly increased after CARTp treatment. The prepro BDNF and mature BDNF protein also increased in level as seen on Western blot analysis. Thus, the neurotrophic effects of CARTp on cultured hippocampal neurons are mediated through the upregulation of BDNF mRNA expression and protein synthesis. The results of the present study suggest the therapeutic efficacy of CARTp in neurodegenerative disorders.

Animals↗

PubMed2006

[Lumbar interbody fusion using autologous bone marrow mesenchymal stem cell-calcium phosphate ceramic composite in rhesus monkey].

OBJECTIVE: To determine the osteogenic capacity of autologous bone marrow mesenchymal stem cells (BMSCs)-calcium phosphate ceramic composites in vitro and implanted as a bone graft substitute for lumbar anterior interbody fusion in rhesus monkeys. METHODS: From March 2003 to April 2005, 9 adult rhesus monkeys underwent lumbar L(3 - 4) and L(5 - 6) discectomy and interbody fusion via an anterior retroperitoneal approach. Two fusion sites in each animal were randomly assigned to two of three treatments: autogenous tricortical iliac crest bone graft (autograft group, n = 6) or cell-free ceramic graft (ceramic group, n = 6) or BMSCs-ceramic composite graft (BMSCs group, n = 6). Autologous BMSCs were culture-expanded and stimulated with osteogenic supplement. The cell-ceramic composites were constructed in a rotary dynamic cell culture system. The spinal fusion segments were evaluated by radiography, biomechanical testing, histologic analysis and histomorphometric analysis at 3 months post-surgery. RESULTS: Biomechanical testing showed that spinal segments from the autograft group and the BMSCs-ceramic group were statistically and significantly stiffer than the cell-free ceramic group. The BMSCs-ceramic group and the autograft group showed equivalent biomechanical stiffness by statistical analysis. Histologically, both the autograft group and the BMSCs-ceramic group achieved osseous union, but the cell-free ceramic group had a fibrous union. Quantitative histologic analysis showed that the amount of bone formation was significantly greater in the autograft group and the BMSCs-ceramic group compared with the cell-free ceramic group. However, the amount of ceramic residue was significantly greater in the cell-free ceramic group versus the BMSCs-ceramic group. CONCLUSIONS: The results indicate that BMSC-ceramic composites can enhance bone regeneration and achieve osseous spinal fusion 3 months after the implantation in rhesus monkey interbody fusion model. Cell-free ceramics has an unsatisfactory efficacy in spinal fusion due to its tense fibrous fusion.

Animals↗

PubMed2006

Removal of salicylic acid on perovskite-type oxide LaFeO3 catalyst in catalytic wet air oxidation process.

It has been found that salicylic acid can be removal effectively at the lower temperature of 140 degrees C on perovskite-type oxide LaFeO3 catalyst in the catalytic wet air oxidation (CWAO) process. Under the same condition, the activities for the CWAO of phenol, benzoic acid and sulfonic salicylic acid have been also investigated. The results indicated that, with compared to the very poor activities for phenol and benzoic acid, the activities for salicylic acid and sulfonic salicylic acid were very high, which are attributed to their same intramolecular H-bonding structures. With the role of hard acidity of intramolecular H-bonding, salicylic acid and sulfonic salicylic acid can be adsorbed effectively on the basic center of LaFeO3 catalyst and are easy to take place the total oxidation reaction. However, at temperatures higher than 140 degrees C, the intramolecular H-bonding structure of salicylic acid was destroyed and the activities at 160 and 180 degrees C decreased greatly, which confirms further the key role of intramolecular H-bonding in the CWAO. Moreover, the LaFeO3 catalyst also indicated a superior stability of activity and structure in CWAO of salicylic acid.

Air↗

PubMed2006

Linking social capital and self-rated health: a multilevel analysis of 11,175 men and women in Sweden.

This multilevel study included 11,175 participants interviewed 2000-2002 in Sweden. The association between neighbourhood linking social capital (voting in national elections) and self-rated health was analysed. Individuals living in neighbourhoods with the lowest levels of linking social capital exhibited a significantly higher risk of poor health than individuals living in neighbourhoods with the highest levels of linking social capital, after adjustment for individual characteristics, including individual voting. The neighbourhood variance indicated significant differences in self-rated health between neighbourhoods. Both individuals and neighbourhoods need to be targeted in order to enhance people's health in neighbourhoods with low linking social capital.

Adult↗

PubMed2006

Pd(II)-catalyzed enantioselective oxidative tandem cyclization reactions. Synthesis of indolines through C-N and C-C bond formation.

We have developed an efficient Pd(II)-catalyzed enantioselective oxidative tandem cyclization strategy using molecular oxygen as a green oxidant for the double 5-exo-trig cyclizations of N-(2-allylaryl) amides to afford a variety of indolines in good yields without the formation of undesired monocyclization products. By employing Pd(TFA)2/(-)-sparteine as the chiral catalyst, we obtained tandem cyclization products with high enantioselectivity (up to 91% ee).

Catalysis↗

PubMed2006

Quantitative determination of six major triterpenoids in Ganoderma lucidum and related species by high performance liquid chromatography.

A reversed-phase liquid chromatographic method was developed for the quantitative determination of six triterpenoids, namely ganoderic acids C2, B, AM1, K, H and D in Ganoderma lucidum and its related species. Samples were extracted with chloroform in ultrasonic bath. The optimal conditions of separation and detection were achieved on an Agilent Zorbax SB-C18 column (250 mmx4.6 mm, 5 microm), with a linear gradient of acetonitrile and 0.03% aqueous phosphoric acid (v/v), at a flow rate of 1.0 ml/min, detected at 252 nm. All calibration curves showed good linearity (r2>0.999) within test ranges. The relative deviation of this method was less than 2% for intra- and inter-day assays, and the percentage recovery of the method was 93-103%, with relative standard deviation (R.S.D.) less than 5%. The current assay method was applied to quantitative determination of constituents of triterpenoids in 36 different samples of G. lucidum and its related species. The results indicated that the developed method could be readily utilized as a quality control method for G. lucidum and related species.

Chromatography, High Pressure Liquid↗

PubMed2006

Apelin and its receptor are expressed in human osteoblasts.

OBJECTIVES: Apelin is a recently discovered peptide that is the endogenous ligand for the orphan G-protein-coupled receptor APJ. Adipocytes can express and secrete apelin. The aim of this study was to characterize apelin and APJ expression in human osteoblasts and to investigate the effects of apelin on osteoblasts. RESULTS: Apelin and APJ were expressed in human osteoblasts. Apelin stimulated proliferation of human osteoblasts, but had no effect on alkaline phosphatase (ALP) activity, osteocalcin and type I collagen production in human osteoblasts. Suppression of APJ with small-interfering RNA (siRNA) abolished the apelin-induced cell proliferation. Apelin induced activation of Akt (Phosphatidylinositol-3 kinase downstream effector), but not MAPKs, such as c-jun N-terminal Kinase (JNK), p38 and ERK1/2 in human osteoblasts. This effect was blocked by suppression of APJ with siRNA. Furthermore, LY294002 (PI3 kinase inhibitor) blocked the activation of Akt by apelin and abolished the apelin-induced cell proliferation. CONCLUSIONS: Human osteoblasts express apelin and APJ and apelin enhances human osteoblast proliferation, but has no effect on osteoblast differentiation, and APJ/PI3 kinase/Akt pathway is involved in the proliferation response. These findings suggest that apelin may function as a mitogenic agent for osteoblasts.

Adolescent↗

PubMed2006

Crucian carp (Carassius carassius) VTG monoclonal antibody: development and application.

The vitellogenin (VTG) in fish has been used as an important biomarker for monitoring endocrine disrupting compounds (EDCs). This paper reports the development of a new monoclonal antibody (McAb) against the VTG of crucian carp (Carassius carassius). The McAb has a molecular weight of 149.4 kDa (heavy chain: 53.1 kDa; light chain: 21.6 kDa), and double diffusion indicated that it belongs to the IgG1 subclass. The titer is 10(5)-10(6) and the affinity constant (K(aff)) is 7.0 x 10(8)L/mol, showing the high specificity and sensitivity of the antibody. The established sandwich ELISA was sensitive with a detection limit of VTG 0.98 ng/mL. The cross-reactivity of antibody was detected in cyprinids such as rare minnow, zebrafish, and carp. This ELISA was used to detect the variation of VTG in crucian carp exposed to secondary effluent and reclaimed water from the Gaobeidian sewage treatment plant (SRP). The VTG induction in secondary effluent was higher than that in reclaimed effluent and the VTG levels in juvenile crucian carp increased with increasing exposure time. The VTG concentration in male fish from downstream of the Gaobeidian STP was 88.62+/-827.73 microg/mL, while that from a control site was undetectable.

Animals↗

PubMed2006

Structure of a flavonoid glucosyltransferase reveals the basis for plant natural product modification.

Glycosylation is a key mechanism for orchestrating the bioactivity, metabolism and location of small molecules in living cells. In plants, a large multigene family of glycosyltransferases is involved in these processes, conjugating hormones, secondary metabolites, biotic and abiotic environmental toxins, to impact directly on cellular homeostasis. The red grape enzyme UDP-glucose:flavonoid 3-O-glycosyltransferase (VvGT1) is responsible for the formation of anthocyanins, the health-promoting compounds which, in planta, function as colourants determining flower and fruit colour and are precursors for the formation of pigmented polymers in red wine. We show that VvGT1 is active, in vitro, on a range of flavonoids. VvGT1 is somewhat promiscuous with respect to donor sugar specificity as dissected through full kinetics on a panel of nine sugar donors. The three-dimensional structure of VvGT1 has also been determined, both in its 'Michaelis' complex with a UDP-glucose-derived donor and the acceptor kaempferol and in complex with UDP and quercetin. These structures, in tandem with kinetic dissection of activity, provide the foundation for understanding the mechanism of these enzymes in small molecule homeostasis.

Crystallography, X-Ray↗

PubMed2006

IRF-8/interferon (IFN) consensus sequence-binding protein is involved in Toll-like receptor (TLR) signaling and contributes to the cross-talk between TLR and IFN-gamma signaling pathways.

Toll-like receptor (TLR) and interferon-gamma (IFN-gamma) signaling pathways are important for both innate and adaptive immune responses. However, the cross-talk between these two signaling pathways is incompletely understood. Here we show that IFN-gamma and LPS synergistically induce the expression of proinflammatory factors, including interleukin-1 (IL-1), IL-6, IL-12, NO, and tumor necrosis factor-alpha (TNF-alpha). Comparable synergism was observed between IFN-gamma and peptidoglycan (PGN; a TLR2 ligand) and poly(I:C) (a TLR3 ligand) in the induction of IL-12 promoter activity. IFN-gamma enhanced lipopolysaccharide (LPS)-induced ERK and JNK phosphorylation but had no effect on LPS-induced NF-kappaB activation. Interestingly, we found that IRF-8-/- macrophages were impaired in the activation of LPS-induced ERK and JNK and the production of proinflammatory cytokines induced by LPS or IFN-gamma plus LPS. Retroviral transduction of IRF-8 into IRF-8-/- macrophages rescued ERK and JNK activation. Furthermore, co-immunoprecipitation experiments show that IRF-8 physically interacts with TRAF6 at a binding site between amino acid residues 356 and 305 of IRF-8. Transfection of IRF-8 enhanced TRAF6 ubiquitination, which is consistent with a physical interaction of IRF-8 with TRAF6. Taken together, the results suggest that the interaction of IRF-8 with TRAF6 modulates TLR signaling and may contribute to the cross-talk between IFN-gamma and TLR signal pathways.

Cell Line↗

PubMed2006

Characterization of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen) by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

The qualitative analysis of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen in Chinese) was performed using high-performance liquid chromatography with electrospray ionization tandem mass spectrometry (ESI-MS(n)). Tanshinones are the major bioactive constituents of Dan-shen, which is used in China for the treatment of haematological abnormalities and cardiovascular diseases. The ESI-MS(n) fragmentation behavior of tanshinones was investigated. For tanshinones with the tanshinone I nucleus, the fragmentation was triggered by loss of a molecule of CO except bearing a substituent at C17 or C18, followed by sequential eliminations of CO. If C(15-16) was a saturated bond, the fragmentation was triggered by elimination of a molecule of H2O. For tanshinones with the tanshinone IIA nucleus, the fragmentation was triggered by loss of a molecule of H2O, followed by successive eliminations of CO. Ions corresponding to loss of a molecule of propylene (Delta m = 42) were also observed. Moreover, when C(15-16) was a saturated bond, ions corresponding to losses of CH3, H2O and propylene were more abundant. If no D-ring existed, the presence of isopropyl resulted in an elimination of a molecule of H2O with an adjacent CO or OH. In addition, the extension of the pi-conjugation in the A-ring (especially at C(1-2)) induced the fragmentation by loss of a molecule of CO. These fragmentation rules were applied to the identification of tanshinones in a chloroform/methanol (3:7) extract of Dan-shen, which was separated on a C18 column with gradient elution. A total of 27 tanshinones were identified, including five new constituents. The established method could be used for the sensitive and rapid identification of tanshinones in the Dan-shen drug and its pharmaceutical preparations.

Abietanes↗

PubMed2006

Application of PCR-DGGE to analyse the yeast population dynamics in slurry reactors during degradation of polycyclic aromatic hydrocarbons in weathered oil.

Slurry-phase reactors have been used to investigate the biodegradation feasibility of polycyclic aromatic hydrocarbons (PAHs) in weathered crude oil, by mixed culture containing five PAHs-degrading yeast strains. Yeasts were isolated from the oily soil by enrichment culture, using phenanthrene as a sole carbon source, and identified based on the 26S ribosomal DNA (rDNA) sequence. Yeast strains belonged to the genera Candida, Pichia, Rhodotorula and Sporidiobolus. The experiment was carried out for a period of 6 weeks at room temperature with a solid : liquid ratio of 50% w/w. The results showed that high removal efficiency was obtained for all PAHs, including low molecular weight (LMW) and high molecular weight (HMW) compounds (89.3-98.6% and 66.3-89.4% within 6 weeks, respectively). The higher removal efficiency for HMW-PAHs obtained in this work suggested that yeast strains mixture could play an important role to reclaim oil-contaminated sites. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified 26S rRNA genes was used to follow the changes of yeast populations during the slurry reactor process. The results of DGGE indicated that Candida maltosa-like and Pichia guilliermondii were the dominant species but Rhodotorula dairenensis appeared as a weak band and Sporidiobolus salmonicolor and Pichia anomala disappeared during the study. Moreover, the results showed that all of the five strains, including the two belonging to the same genus, could be differentiated from each other in the DGGE profile.

Base Sequence↗

PubMed2006

Molecular characterization of a bacterial consortium enriched from an oilfield that degrades phenanthrene.

Characterization of functional and phylogenetic genes was carried out on a bacterial consortium, enriched from a water treatment system of an oilfield, that could use phenanthrene as the sole carbon source. The mixed culture degraded 130 mg phenanthrene l(-1) in 16 days, which is significantly faster than previously reported pure cultures. The existence of catabolic genes (nahAc, C23O) in the mixed culture was quantitated by most probable number PCR. The plasmid encoding phenanthrene catabolic genes increased relative to the chromosome genes. Heterogeneous bacteria were present according to both PCR denaturing gradient gel electrophoresis and cloning methods, suggesting the possible existence of cooperation between different biochemical PAH-transforming pathways.

Bacteria↗

PubMed2006

Isolation and characterization of a pseudomonas oleovorans degrading the chloroacetamide herbicide acetochlor.

To date, no pure bacterial cultures that could degrade acetochlor have been described. In this study, one strain of microorganism capable of degrading acetochlor, designated as LCa2, was isolated from acetochlor-contaminated soil. The strain LCa2 is Pseudomonas oleovorans according to the criteria of Bergey's manual of determinative bacteriology and sequence analysis of the partial 16S rRNA gene. Optimum growth temperature and pH were 35 degrees C and 8.0, respectively. The strain could degrade 98.03% of acetochlor treated at a concentration of 7.6 mg l(-1) after 7 days of incubation and could tolerate 200 mg l(-1) of acetochlor. When the acetochlor concentration became higher, the degradation cycle became longer. The acetochlor biodegradation products were identified by GC-MS based on mass spectral data and fragmentation patterns. The main plausible degradative pathways involved dechlorination, hydroxylation, N-dealkylation, C-dealkylation and dehydrogenation.

Herbicides↗

PubMed2006

The frequency dependence of ultrasonic velocity and the anisotropy of dispersion in both freshly excised and formalin-fixed myocardium.

The objectives of this study were to measure the frequency dependence of the ultrasonic velocity in myocardium and to quantify the frequency dependence of phase velocity as a function of the insonification angle relative to the predominant direction of the myofibers. Broadband phase spectroscopy data were acquired, spanning a frequency range of 3 to 8 MHz. Measurements were made on 36 tissue specimens cored from 12 freshly excised lamb hearts and were repeated after fixation with formalin. Measured phase velocities were found to be well characterized by a logarithmic fit. For freshly excised myocardium, the dispersion over the 3 to 8 MHz bandwidth was dependent on the direction of insonification, ranging from 1.2 m/s change for perpendicular insonification (across the myofibers) to 3.7 m/s for parallel insonification (along the myofibers). The effects of formalin-fixation resulted in a significant increase in dispersion for perpendicular insonification, but did not appreciably alter the dispersion for parallel insonification.

Animals↗

PubMed2006

Four new lignans from the stems of Kadsura heteroclita.

Two new C(18) dibenzocyclooctadiene lignans named heteroclitalignans A and B (1 and 3), one new C(19) homolignan named heteroclitalignan C(4) and one new natural product named heteroclitalignan D(2), together with the four known lignans kadsurarin (5), kadsulignan E (6), d-epigalbacin, and meso-dihydroguaiaretic acid were isolated from the stems of Kadsura heteroclita. The structures of these compounds were characterized by extensive 1D and 2D NMR spectral data analysis.

Humans↗

PubMed2006

Elastic stiffness coefficients (c11, C33, and C13) for freshly excised and formalin-fixed myocardium from ultrasonic velocity measurements.

The goal of this study was to measure elastic stiffness coefficients of freshly excised and subsequently formalin-fixed myocardial tissue. Our approach was to measure the angle-dependent phase velocities associated with the propagation of a longitudinal ultrasonic wave (3-8 MHz) in ovine myocardium using phase spectroscopy techniques and to interpret the results in the context of orthotropic and transversely isotropic models describing the elastic properties of myocardium. The phase velocity results together with density measurements were used to obtain the elastic stiffness coefficients c11, c33, and c13 for both symmetries. The results for the elastic stiffness coefficients c11, c33, and c13 are the same for both symmetries. Measurements for freshly excised myocardium and the same tissue after a period of formalin fixation were compared to examine the impact of fixation on the elastic stiffness coefficients.

Animals↗

PubMed2006

Measurements of the anisotropy of ultrasonic attenuation in freshly excised myocardium.

Echocardiography requires imaging of the heart with sound propagating at varying angles relative to the predominant direction of the myofibers. The degree of anisotropy of attenuation can significantly influence ultrasonic imaging and tissue characterization measurements in vivo. This study quantifies the anisotropy of attenuation of freshly excised myocardium at frequencies typical of echocardiographic imaging. Results show a significantly larger anisotropy than previously reported in specimens of locally unidirectional myofibers. Through-transmission radio frequency-based measurements were performed on specimens from 12 ovine and 12 bovine hearts. Although ovine hearts are closer in size to human, the larger size of bovine hearts offers the potential for specimens in which myofibers are more nearly unidirectionally aligned. The attenuation coefficient increased approximately linearly with frequency. The mean slope of attenuation with frequency was 3-4 times larger for propagation parallel than for perpendicular to the myofibers. At perpendicular insonification, slopes between ovine and bovine myocardium were approximately equal. However, attenuation in bovine specimens was larger for angles approaching parallel. The difference in results for parallel appears consistent with what might be expected from increased myofiber curvature associated with smaller lamb hearts. Quantitative knowledge of anisotropy of attenuation may be useful in understanding mechanisms underlying the interaction of ultrasound with myocardium.

Animals↗