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Objective To establish the synthetic method of the substrate for angiotensin-converting enzyme(ACE),and investigate the assay method of sernm ACE. Methods The substrate was prepared by the use of N-hydroxysuccinimide ester in peptide synthesis,and serum ACE was determined by spectrophotometric assay using suhstrate. Results The substrate of furanacryloyl-phenylalanyl-glycyl-glycine with purity of 99.5% was obtained.The K_m value for the substrate was 0.25 mmol/L,the normal reference interval for serum ACE activity was 46.7 U/L to 113.3 U/L,and the within-run and between-run coefficient of variation(CVs)ranged from 3.9 to 4.9%.The serum ACE activity in patients with squamous carcinoma and adenocarcinoma of lung were significantly decreased(P<0.05),while that in patients with lung small cell carcinoma was not significantly decreased(P>0.05). Conclusion The synthesized substrate could be reliably used as a marker for diagnosis of different lung cancers in clinics.
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In this study, calcium phosphate cements (CPC) were prepared by mixing cement powders of tetracalcium phosphate (TTCP) with a cement liquid of phosphate acid saline solution. Tetracycline (TTC)-CPC, chitosan-CPC and chitosan-TTC-CPC were investigated with different premixed schedule. It was demonstrate that both TTC and chitosan worked on the phase transition and crystal characteristics. TTCP mixed with phosphate acid saline solution had similar features of Fourier transform-infrared spectrometry (FT-IR) no matter it was mixed with chitosan or TTC or both. TTC premixed with cement liquid or powder had significant different features of FT-IR and 876 cm(-1) seemed to be a special peak for TTC when TTC was premixed with cement liquid. This was also supported by XRD analysis, which showed that TTC premixed with cement liquid improved phase transition of TTCP to OCP. Chitosan, as organic additive, regulates the regular crystal formation and inhibits the phase transition of TTCP to OCP, except when it is mingled with cement liquid premixed with TTC in field scanning electron microscope. It was concluded that the premixed schedule influences the crystal formation and phase transition, which may be associated with its biocompatibility and bioactivities in vivo.
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Object To study the chemical constituents of Hibiscus mutabilis L.Methods Isolation and purification were carried out on silica gel, or polyamide column chromatography etc. Constituents were identified and structurally elucidated by physicochemical properties and spectral analysis.Results Ten compounds were obtained, nine of them were determined as tetracosanoic acid (Ⅰ), ?-sitosterol (Ⅱ), daucosterol (Ⅲ), salicylic acid (Ⅳ), emodin (Ⅴ), rutin (Ⅵ), kaempferol-3-O-?-rutinoside (Ⅶ), kaempferol-3-O-?-robinobinoside (Ⅷ) and kaempferol-3-O-?-D-(6-E-p-hydroxycinnamoyl)-glucopyranoside (Ⅸ).Conclusion All compounds are isolated from the plant for the frist time except Ⅱ and Ⅵ.
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Objective: To study the optimum extraction conditions of flavonoids from the leaves of Hibiscus mutabilis L. Methods: The orthogonal design L 9(3 4) was used. The 70% alcohol refluent method was compared with the decoction or 75% alcohol warm infusion process. Results: The 70% alcohol reflux was the best method.Conclusion: A 1B 3C 3D 3 is the best extraction condition of flavonoids from the leaves of Hibiscus mutabilis L..