[Brief introduction on compilation and editions of Yang ke xuan cui].

Yang ke xuan cui («¼) is a surgical work compiled by Chen Wenzhi () of the Ming Dynasty. There are few of research on the completion and author of the book. Based on the evidences in the local chronicles, the prefaces and postscripts of the book, it has been verified that the book was originally completed no later than 1591, and Chen Wenzhi passed away no later than 1623. After investigating the 6 editions collected by 8 institutions, a collection of 11 books in total, by comparing the characteristics and circulation relationship of each edition, two systems of circulation were sorted out: block-printed edition of Xu Xi () and review edition of Xu Dachun ().

[Strategies for demineralized dentin matrix protection and its research progress in dentin-resin bonding restoration].

Both pathological injuries and clinical iatrogenic operations can lead to dentin demineralization, forming demineralized dentin matrix (DDM). Dentin demineralization activates endogenous matrix metalloproteinase (MMP) and cysteine cathepsin (CC), and the mechanical properties of DDM decrease, so DDM is prone to lose its structural integrity under the action of enzymatic degradation and mechanical destruction, which in turn results in the reduction of clinical functional value of DDM in dentin-resin bonding restoration. The administrations of dentin collagen cross-linking reagents and MMP/CC inhibitors are effective strategies to protect DDM structural integrity and achieve its clinical functional value. A variety of chemically synthesized reagents and plant-derived extracts are capable of significantly improving the mechanical properties of DDM and enhancing its enzymatic tolerance. However, the cytotoxicity caused by chemically synthesized reagents and the tooth staining aroused by plant extracts have considerably affected their clinical applicability. Protecting dentin collagen while exerting antibacterial properties is a new direction for future DDM protective agent research. Accordingly, from the perspectives of cross-linking reagents, enzyme inhibitors and compounds which possess the dual proper ties, this review discusses the latest research progress in DDM protection, and looks into its application prospects in dentin-resin bonding, in an attempt to provide reference for the clinical promotion of DDM protection strategy.

Rapid conversion of tea catechins to monomethylated products by rat liver cytosolic catechol-O-methyltransferase.

1. The metabolic O-methylation of several catechol-containing tea polyphenols by rat liver cytosolic catechol-O-methyltransferase (COMT) has been studied. 2. When (-)-epicatechin was used as substrate, its O-merthylation showed dependence on incubation time, cytosolic protein concentration, incubation pH and concentration of S-adenosyl-L-methionine. The O-methylation of increasing concentrations of (-)-epicatechin followed typical Michaelis-Menten kinetics, and the apparent Km and Vmax were 51 microM and 2882 pmol mg protein(-1) min(-1), respectively, at pH 7.4, and were 17 microM and 2093 pmol mg protein(-1) min(-1), respectively, at pH 10.0. 3. Under optimized conditions for in vitro O-methylation, (-)-epicatechin, (+)-epicatechin and (-)-epigallocatechin were rapidly O-methylated by rat liver cytosol. In comparison, (-)-epicatechin gallate and (-)-epigallocatechin gallate vere O-methylated at significantly lower rates under the same reaction conditions. catalysed O-methylation of (-)-epicatechin and (-)-epigallocatechin was inhibited in a concentration-dependent manner by S-adenosyl-L-homocysteine, a demethylated product of S-adenosyl-L-methionine. The IC50 was approximately 10 microM. 5. In summary, the results showed that several catechol-containing tea polyphenols were rapidly O-methylated by rat liver cytosolic COMT. These observations raise the possibility that some of the biological effects of tea polyphenols may be exerted by their O-methylated products or may result from their potential inhibition of the COMT-catalysed O-methylation of endogenous catecholamines and catechol oestrogens.

O-Methylation of tea polyphenols catalyzed by human placental cytosolic catechol-O-methyltransferase.

In the present study, we evaluated the metabolic O-methylation of several catechol-containing tea polyphenols by human placental catechol-O-methyltransferase (COMT). (-)-Epicatechin, (+)-epicatechin, and (-)-epigallocatechin were good substrates for metabolic O-methylation by placental cytosolic COMT (150-500 pmol/mg of protein/min), but (-)-epicatechin gallate and (-)-epigallocatechin gallate were O-methylated at much lower rates (<50 pmol/mg of protein/min). When (-)-epicatechin was used as substrate, its O-methylation by human placental COMT showed dependence on incubation time, cytosolic protein concentration, incubation pH, and concentration of S-adenosyl-L-methionine (the methyl donor). Analysis of cytosolic COMT from six human term placentas showed that the O-methylation of increasing concentrations of (-)-epicatechin or (-)-epigallocatechin follows typical Michaelis-Menten kinetics, with K(m) and V(max) values of 2.2 to 8.2 microM and 132 to 495 pmol/mg of protein/min for (-)-epicatechin and 3.9 to 6.7 microM and 152 to 310 pmol/mg of protein/min for (-)-epigallocatechin, respectively. Additional analysis revealed that COMT-catalyzed O-methylation of (-)-epicatechin and (-)-epigallocatechin was strongly inhibited in a concentration-dependent manner by S-adenosyl-L-homocysteine (IC(50) = 3.2-5.7 microM), a demethylated product of S-adenosyl-L-methionine. This inhibition by S-adenosyl-L-homocysteine follows a mixed (competitive plus noncompetitive) mechanism of enzyme inhibition. In summary, several catechol-containing tea polyphenols are rapidly O-methylated by human placental cytosolic COMT. This metabolic O-methylation is subject to strong inhibitory regulation by S-adenosyl-L-homocysteine, which is formed in large quantities during the O-methylation of tea polyphenols.

Dietary administration of an extract from rosemary leaves enhances the liver microsomal metabolism of endogenous estrogens and decreases their uterotropic action in CD-1 mice.

We evaluated the effects of a methanol extract from the leaves of the plant Rosmarinus officinalis L. (rosemary) on the metabolism and action of estradiol and estrone. Treatment of female CD-1 mice with 2% rosemary in AIN-76A diet for 3 weeks increased the liver microsomal 2-hydroxylation of estradiol and estrone by approximately 150%, increased their 6-hydroxylation by approximately 30% and inhibited the 16alpha-hydroxylation of estradiol by approximately 50%. Treatment of female CD-1 mice with 2% rosemary diet for 3 weeks also stimulated the liver microsomal glucuronidation of estradiol and estrone by 54-67% and 37-56%, respectively. In additional studies, feeding 2% rosemary diet to ovariectomized CD-1 mice for 3 weeks inhibited the uterotropic action of estradiol and estrone by 35-50% compared with animals fed a control diet. The results of this study showed that feeding female mice a 2% rosemary diet increased the liver microsomal oxidation and glucuronidation of estradiol and estrone and inhibited their uterotropic action.