There is increasing evidence of a biochemical link between lipid oxidation and bone metabolism. Paraoxonase 1 (PON1) prevents the oxidation of low-density lipoprotein (LDL) and metabolizes biologically active phospholipids in oxidized LDLs. Here, we performed association analyses of genetic variation in PON1 to ascertain its contribution to osteoporotic fractures (OFs) and bone mineral density (BMD). We directly sequenced the PON1 gene in 24 Korean individuals and identified 26 sequence variants. A large population of Korean postmenopausal women (n=1,329) was then genotyped for eight selected PON1 polymorphisms. BMD at the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Lateral thoracolumbar (T4-L4) radiographs were obtained for vertebral fracture assessment, and the occurrence of non-vertebral fractures (i.e., wrist, hip, forearm, humerus, rib, and pelvis) was examined using self-reported data. Multivariate analyses showed that none of the polymorphisms was associated with BMD at either site. However, +5989A>G and +26080T>C polymorphisms were significantly associated with non-vertebral and vertebral fractures, respectively, after adjustment for covariates. Specifically, the minor allele of +5989A>G exerted a highly protective effect against non-vertebral fractures (OR=0.59, P=0.036), whereas the minor allele of +26080T>C was associated with increased susceptibility to vertebral fractures (OR=1.73, P=0.020). When the risk for any OFs (i.e., vertebral or non-vertebral) was considered, the statistical significance of both polymorphisms persisted (P=0.002-0.010). These results suggest that PON1 polymorphisms could be one of useful genetic markers for OF risk in postmenopausal women. 相似文献
Paraoxonase 1 (PON1: EC 3.1.8.1) is a calcium-dependent enzyme associated with high-density lipoproteins (HDLs) and has a protective effect against oxidation of low-density lipoproteins (LDLs) in mammals. PON1 is the best-studied member of a family of enzymes called serum paraoxonases, or PONs, identified in mammals and other vertebrates as well as in invertebrates. PONs exhibit a range of important activities, including drug metabolism and detoxification of organophosphates such as nerve agents. This study reports, for the first time, purification and biochemical characterization of serum PON1 from different bovine breeds namely Swiss Black, Holstein, and Montofon. Bovine serum PON1s were purified using ammonium sulfate precipitation followed by Sepharose-4B-l-tyrosine-1-naphthylamine hydrophobic interaction chromatography. SDS–polyacrylamide gel electrophoresis of the purified enzymes indicates a single band with an apparent MW of 43 kDa. The purified enzymes had a specific activity of 10.78, 27.00, and 22.38 U/mg for Swiss Black, Holstein, and Montofon bovines, respectively. The overall purification rates of our method were 262.47-, 2,476.90-, and 538.06-fold for Swiss Black, Holstein, and Montofon bovines, respectively. Furthermore, using phenyl acetate as a substrate, we determined the KM and Vmax values of the purified enzymes, as 0.80 mM, 1428.5 U/ml for Swiss Black; 0.40 mM, 714.3 U/ml for Holstein; and 0.50 mM, 1,111.1 U/ml for Montofon bovine. The present study has revealed that there is no substantial difference in PON1 activities among the studied bovine breeds. 相似文献
Abstract— Previous reports showed that the photosensitizer mono- l -aspartyl chlorin e6 (NPe6) binds to serum proteins. However, the influence of this binding on the cellular uptake and photodynamic therapy (PDT) phototoxicity of NPe6 is still undefined. In this paper, we studied how serum in medium affected the P388 cellular uptake and PDT phototoxicity of NPe6 in vitro. This was assessed by (1) detection of the red shift (654 nm Q band peak of absorption) induced by protein binding NPe6; (2) detection of intracellular concentration of NPe6 by HPLC and (3) measurements of the cell survival ratio after PDT by MTT assay. The 654 nm Q band peak of NPe6 shifted to 665 nm after binding of NPe6 and serum proteins. The protein-bound NPe6 cannot be uptaken by cells, thus there was no PDT phototoxicity. Nevertheless, phototoxicity recovered when the concentration of NPe6 excessed the serum protein binding ability or there was free serum protein in the medium. These data suggested that the cellular uptake of NPe6 is inhibited by serum components in the medium, and that only free NPe6 is accumulated by P388 cells even during relatively long incubations. The cytotoxicity of PDT mainly depends on the free NPe6 level in the medium. 相似文献
Chelates formation of Fe(III) with 7–hydroxy–4–methyl coumarin–6–carboxylic acid (HMCCH)2 and 8–amino–7–hydroxy–4–methyl coumarin (AHMCH) have been studied. It has been observed that Fe(III) forms 1:2 (metal:ligand) chelates with HMCCH2 and AHMCH. The stability constants of these chelates at different ionic strengths and the effect of temperature on the stability constants of these chelates have been studied. The thermodynamic parameters such as entropy change (ΔS), free energy of formation (ΔG) and enthalpy change (ΔH) have also been calculated. The effect of dielectric constant oh the stability constants of these chelates have been studied. Estimation of nanogram quantities of Fe(III) with these ligands and the effect of diverse ions have also been studied and the results have been compared with other methods used for estimation of Fe(III). 相似文献
The reaction of 4-methylpyridine and its methiodide with p-N, N-dimethylamino-benzaldehyde gave 4-p-N, N-dimethylaminostyrylpyridine (I) and 4-p-N, N-dimethylaminostyrylpyridine methiodide (II), respectively, II was also prepared by methylation of I with methyl iodide in methanol. The pyridylidene structure of II, N-benzyl-4-(p-N, N-dimethylaminophenyl) pyridinium chloride (IVa) and its methiodide (Va) was discussed in terms of UV, NMR and mass spectra. 相似文献
The air oxidation of As(III) oxides [(PhAsO)x and Ph2As-O-AsPh2] and thioesters [Ph-As(SPh)2, Ph2As-SPh Me-As(SPh)2, Me2As-SPh], in chloroform and in methanol was studied. The air oxidation in chloroform was faster probably because the solubility of dioxygen is greater than in methanol, and it is favored by the electron-withdrawing phenyl groups bound to As(III). The products obtained were the arsonic or arsinic acids and diphenyl disulfide. In one case, diphenyl disulfide and thiophenol were produced. The results can be rationalized by assuming first hydrolysis of the As(III) compounds to arsonous or arsinous acids followed by their oxidation to arsonic and arsinic acids, which should involve the binding of dioxygen to As(III). The other hypothesis assumes first the binding of dioxygen to As(III) of these oxides and thioesters followed by the decomposition of the adducts. The binding of the ground state dioxygen to As(III) may have biochemical implications for toxicity or chemotherapy of arsenic(III) compounds. 相似文献
A large series of 1,2‐diaryl‐benzimidazole and 2‐aryl‐1H‐benzimidazole derivatives were synthesized with slight differences using both microwave irradiation and conventional heating methods. Usually higher yields and time reactions reduction were obtained with the former method. All compounds were assayed for their in vitro ability to inhibit human cyclooxygenases, and most of them showed an encouraging inhibitory activity and isoform selectivity in the micromolar range. 相似文献
The aim of this study was to investigate the possibility to use the bioactive components from cape gooseberry (Physalis peruviana), blueberry (Vaccinium corymbosum), and cranberry (Vaccinium macrocarpon) extracts as a novel source against oxidation in food supplementation. The quantitative analysis of bioactive compounds (polyphenols, flavonoids, flavanols, carotenoids, and chlorophyll) was based on radical scavenging spectrophometric assays and mass spectrometry. The total phenolic content was the highest (P?<?0.05) in water extract of blueberries (46.6?±?4.2 mg GAE/g DW). The highest antioxidant activities by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay and Cupric reducing antioxidant capacity were in water extracts of blueberries, showing 108.1?±?7.2 and 131.1?±?9.6 μMTE/g DW with correlation coefficients of 0.9918 and 0.9925, and by β-carotene linoleate assay at 80.1?±?6.6 % with correlation coefficient of 0.9909, respectively. The water extracts of berries exhibited high binding properties with human serum albumin in comparison with quercetin. In conclusion, the bioactive compounds from a relatively new source of gooseberries in comparison with blueberries and cranberries have the potential as food supplementation for human health. The antioxidant and binding activities of berries depend on their bioactive compounds. 相似文献
The identification of various species present in aqueous solutions of M(III)-Catechol system [M(III) = Ga(III) or In(III)] has been made through conductometric and electrometric studies. With a view to confirm the results suggested by physico-chemical methods, several hexa coordinated complexes of the type K[M(R) (H2O)2 (OH)2]. × H2O, K2[M(R)2(H2O) (OH)]. × H2O, K3[M(R)3]. × H2O (M = Ga(III), In(III)R = C6H4O2?) have been isolated. 相似文献
Researches on the synthesis of sulfur-containing heterocyclic compounds at the G. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, are reviewed. They include the synthesis of thiolane by the recyclization of THF in hydrogen sulfide; the synthesis thiacycloalkanes by the hydrogenation of thiophenes; the synthesis of 4-methylthiazole by the reaction of SO2 with methylisopropylideneamine; the synthesis of thiophenes by the heterocyclization of aliphatic compounds of sulfur and dehydrogenation of thiacycloalkanes; the synthesis of thiolane 1,1-dioxide by the hydrogenation of 2- and 3-thiolene 1,1-dioxides and 3-alkoxythiolane 1,1-dioxides; the synthesis of sulfoxides by the oxidation of thiacycloalkanes with atmospheric oxygen. 相似文献
Trimethylene carbonate (TMC) was copolymerized with D ,L ‐lactide (DLLA) or with ε‐caprolactone (CL), and the degradation of melt‐pressed solid copolymer films in phosphate‐buffered saline at pH 7.4 and 37 °C was followed for a period of over two years. The parent homopolymers were used as reference materials. The degradation profile of TMC‐DLLA‐ and TMC‐CL based copolymers was similar and was best described by autocatalyzed bulk hydrolysis, preferentially of ester bonds. The hydrolysis rates varied by two orders of magnitude, depending on polymer composition and physical characteristics under the degradation conditions. TMC‐DLLA copolymers degraded faster than the parent homopolymers. The copolymers lost their tensile strength in less than five months, after which mass loss occurred. Copolymers with 50 or 80 mol‐% of TMC underwent total degradation in eleven months. For TMC‐CL copolymers, a slow and gradual decrease in molecular weight and deterioration of the mechanical performance was observed. These copolymers maintained suitable mechanical properties for seventeen months or longer. Chain scission in the semicrystalline copolymers resulted in an increase in crystallinity. In comparison with the CL homopolymer, the introduction of a small amount of TMC (10 mol‐%) significantly reduced the increase in crystallinity during degradation. Poly(TMC) specimens were dimensionally stable and showed a negligible decrease in molecular weight. A 60% decrease in the initial tensile strength of the polymer samples was observed after two years.
Russian Journal of General Chemistry - Regioselective synthesis of some novel isoxazole-benzimidazole hybrids in high yields via Cu(I)-catalyzed tandem one-pot reaction of aromatic aldehydes with... 相似文献
Russian Journal of General Chemistry - In vitro antitumor activity of some 4-(1,2,3-thiadiazol-4-yl)furans was studied against erythroleukemia (K562) and cervical carcinoma (HeLa) cell lines. 相似文献
Abstract The intensity of the radiation emitted by humic acid (HA) in the presence of SO52? in basic medium was used to determine HA in the range up to 20.0 mg l?1. The detection limit was 0.24 mg l?1. The addition to the sample of 50 mg l?1 of Co(II) or Mn(II), as EDTA complexes or chloride salts, enhanced the radiation emission as a result of the formation of strong oxidant radicals such as SO5??, SO4??, and HO?. In the presence of these metal ions, the oxidation of HA and the catalytic decomposition of SO52? occur simultaneously. Low concentration of HA in natural waters can be detected. HA was replaced by some model organic compounds. The marked chemiluminescent (CL) signals followed the order: phloroglucinol>fulvic acid>humic acid>resorcinol>pyrogallol>cathecol>hydroquinone. 相似文献