Abnormal hypermethylation and clinicopathological significance of FBLN1 gene in cutaneous melanoma.

Fibulin-1 (FBLN1) is involved in the progression of some types of cancer. However, the role of FBLN1 in cutaneous melanoma (CM) has not been examined. The purpose of this study was to understand the molecular mechanisms and clinical significance of FBLN1 inactivation in CM. The expression of FBLN1 mRNA in CM tissues and adjacent normal skin tissues was analyzed by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). Methylation-specific polymerase chain reaction was performed to examine the methylation status of the FBLN1 gene promoter. Furthermore, the methylation status of FBLN1 was analyzed with the clinicopathological characteristics and overall survival. qRT-PCR showed FBLN1 mRNA levels in cancerous tissues to be significantly decreased compared with that in adjacent normal skin tissues. The rate of FBLN1 promoter methylation was significantly higher in CM tissues than in adjacent normal skin tissues (P < 0.001). Downregulation of FBLN1 was strongly correlated with promoter methylation (P = 0.021). Promoter hypermethylation of FBLN1 was significantly associated with tumor stage (P = 0.019). In addition, FBLN1 methylation status was associated with significantly shorter survival time and was an independent predictor of overall survival. In conclusion, our results indicated that FBLN1 is a novel candidate of tumor suppressor gene and that promoter hypermethylation of FBLN1 is associated with tumor progression in CM.

[Beneficial effects of liver X receptor agonist on adipose-derived mesenchymal stem cells transplantation in mice with myocardial infarction].

OBJECTIVE: To investigate the effects of liver X receptor (LXR) agonist on adipose-derived mesenchymal stem cells (AD-MSCs) implantation into infarcted hearts of mice. METHOD: AD-MSC(Fluc+) which stably expressed firefly luciferase (Fluc) were isolated from ß-actin-Fluc transgenic mice and characterized by flow cytometry. Male FVB mice were randomly allocated into the following four groups (n = 10 each): (1) sham group; (2) MI + PBS group; (3) MI + AD-MSC(Fluc+) group; (4) MI + AD-MSC(Fluc+) + LXR agonist (T0901317) group. AD-MSC(Fluc+) or PBS were injected intramyocardial into peri-infarcted region of mice heart after permanent left anterior descending (LAD) artery ligation. Bioluminescence imaging (BLI) was performed for quantification of injected cells retention and survival. Cardiac function was evaluated by echocardiography. RESULTS: The AD-MSC(Fluc+) were positive for CD44 and CD90 by flow cytometry. BLI evidenced the firefly luciferase expression of AD-MSC(Fluc+) which was positively correlated with cell numbers (r(2) = 0.98). The results of BLI in vivo revealed that LXR agonist could improve the survival of AD-MSC(Fluc+) at day 7, 14 and 21 after transplantation compared with AD-MSC(Fluc+) alone group. Cardiac function was further improved in combination therapy group compared with AD-MSC(Fluc+) alone group (P < 0.05). CONCLUSIONS: LXR agonist T0901317 can improve the retention and survival of intramyocardial injected AD-MSC(Fluc+) post-MI, and the combination therapy of T0901317 and AD-MSC(Fluc+) has a synergetic effect on improving cardiac function in this model.

Molecular approaches to understand biomineralization of shell nacreous layer.

The nacreous layer of molluskan shells, which consists of highly oriented aragonitic crystals and an organic matrix (including chitin and proteins), is a product of biomineralization. This paper briefly introduces the recent research advances on nacre biomineralization of shells from bivalves and gastropods, which mainly focus on analysis of the micro- and nano-structure and components of shell nacreous layers, and investigations of the characteristics and functions of matrix proteins from nacre. Matrix proteins not only participate in construction of the organic nacre framework, but also control the nucleation and growth of aragonitic crystals, as well as determine the polymorph specificity of calcium carbonate in nacre. Moreover, the inorganic aragonite phase also plays an active role in organizing nacre microstructure. Based on these studies, several models to illustrate the formation mechanism related to lamellar nacre in bivalves, and columnar nacre in gastropods are introduced.

GSK-3beta inhibitor modulates TLR2/NF-kappaB signaling following myocardial ischemia-reperfusion.

OBJECTIVE: The present study defines the expression of Toll-like Receptor 2 (TLR2), and the modulatory role of Glycogen synthase kinase (GSK)-3beta inhibitor on TLR2/Nuclear Factor-kappa B (NF-kappaB) signaling following myocardial ischemia-reperfusion (MI-R) injury in rats. METHODS: Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) were used to analyze the presence and quantity of TLR2 mRNA and protein. Tumor necrosis factor (TNF)-alpha mRNA and interleukin-6 (IL-6) mRNA were analyzed by RT-PCR. The activation of NF-kappaB was detected by Western Blot and the myocardial infarct size by Evans blue-TTC staining. RESULTS: Following 30 min of myocardial ischemia, a significant up-regulation of TLR2 mRNA was revealed by RT-PCR from 1 to 24 h post reperfusion. IHC demonstrated high protein expression levels of TLR2. Administration of the GSK-3beta inhibitor 4-benzyl-2-methyl-1, 2, 4-thiadiazolidine-3, 5-dione (TDZD-8) 5 min prior to reperfusion following 1 h reperfusion down-regulated mRNA levels of TLR2 and downstream proinflammatory cytokines (P < 0.05 vs. MI-R), decreased the activity of NF-kappaB and the size of the myocardial infarct (P < 0.05 vs. MI-R). CONCLUSION: Our results demonstrate that TLR2 and its signaling components are activated by MI-R. TDZD-8 administration attenuates TLR2/NF-kappaB signaling, suggesting a possible mechanism whereby GSK-3beta inhibition improves the outcome of MI-R.

Reactive oxygen species production and Bax/Bcl-2 regulation in honokiol-induced apoptosis in human hepatocellular carcinoma SMMC-7721 cells.

We investigated possible mechanism(s) where honokiol induces apoptosis in human hepatocellular carcinoma SMMC-7721 cells. MTT assay showed that honokiol has strong inhibition on SMMC-7721 cells in a dose-dependent manner. SMMC-7721 cells after honokiol treatment display morphological characteristics such as cell shrinkage, detachment from the culture plate, formation of apoptotic bodies, change to a round shape, and marked nuclear condensation and fragmentation after 32258 staining. Cell apoptosis was measured by Annexin-V/PI staining and alternatively, by the subG0/G1 percentage of the cell cycle analysis followed by FACS. An obvious loss of ΔΨ(m) and a quick burst of ROS was detected when honokiol reached 4µg/ml, which was coincident with the high apoptosis percentage in our previous research. Up-regulation of Bax and down-regulation of Bcl-2 were observed, suggesting that honokiol-induced apoptosis was associated with reactive oxygen species (ROS) production and an increase of Bax/Bcl-2 ratios.

Effect of O-superfamily conotoxin SO3 on synchronized spontaneous calcium spikes in cultured hippocampal networks.

SO3 belongs to the O-superfamily of conotoxins and is known to have analgesic effects in experimental animals. In order to explore the mechanism of its potential pharmacological actions, the effect of SO3 on synchronized spontaneous calcium spikes was examined in cultured hippocampal networks by calcium imaging. Spontaneous oscillations of intracellular concentrations of calcium (Ca(2+)) in the form of waves and spikes are found in cultured hippocampal networks. Exposure to increasing concentrations of SO3 resulted in a progressive decrease in synchronized spontaneous calcium spikes. The higher concentrations (0.1 micromol/L and 1 micromol/L) of SO3 showed the strongest inhibition. The rank order of inhibition was 1 micromol/L > 0.1 micromol/L > 10 micromol/L > 0.01 micromol/L. This action of SO3 in reducing synchronized calcium spikes suggests a possible application for therapeutic treatment of epilepsy.

[Effects of constant magnetic fields on proliferation and migration of endothelial progenitor cells under rapamycin intervention: experiment with rats].

OBJECTIVE: To investigate the effects of constant magnetic field (CMF) on proliferation and migration of bone marrow-derived endothelial progenitor cells (EPCs) under rapamycin intervention. METHODS: EPCs were isolated from rat bone marrow by density gradient centrifugation and cultured on fibronectin-coated dishes. Six days later the attached cells were divided into 5 groups: control group, rapamycin (1 ng/ml) group, and 3 rapamycin + CMF groups (treated with CMF of the doses 0.1 mT, 0.5 mT, and 1.0 mT respectively). Samples were collected 24 hours after incubation. Cell proliferation was measured by MTT chromatometre. EPC migration was detected with modified Boyden chamber assay. RESULTS: The EPC proliferation ability of the rapamycin group, expressed by absorbance, was (0.252 +/- 0.006), significantly lower than that of the control group [(0.328 +/- 0.025), P < 0.05]. The number of migrating EPC was (31 +/- 3) cells, significantly lower than that of the control group [(48 +/- 5), P < 0.05]. The EPC proliferation ability of the rapamycin + CMF 0.5 mT and 1.0 mT groups, expressed by absorbance, were (0.278 +/- 0.008) and (0.280 +/- 0.010) respectively, both significantly higher than that of the control group (both P < 0.05). The migrating EPC number of the rapamycin + CMF 0.5 mT and 1.0 mT groups were (37 +/- 3) and (38 +/- 4) respectively, both significantly higher than that of the control group (both P < 0.05). CONCLUSION: CMF of the doses of 0.5 mT and 1.0 mT antagonizes the effects of rapamycin on EPCs, increasing the proliferation and migration of EPCs.

A novel glycosylphosphatidylinositol-anchored alkaline phosphatase dwells in the hepatic duct of the pearl oyster, Pinctada fucata.

Alkaline phosphatases are ubiquitous enzymes involved in many important biological processes. Mammalian tissue-nonspecific alkaline phosphatase (TNAP) has long been thought to play an important role in bone mineralization. In this study, we identified a full-length cDNA encoding a potential alkaline phosphatse from pearl oyster Pinctada fucata by RT-PCR and RACE and designated the encoded protein as PFAP. The sequence of PFAP shares an overall similarity of 67% with that of human TNAP. Prediction and analysis of its secondary and tertiary structure revealed that the PFAP contains two mammalian-specific regions, the crown domain, involved in collagen binding, and the calcium binding domain, which hint its potential ability to participate in biomineralization. RT-PCR and in situ hybridization showed that the PFAP mRNA distributes specifically in the hepatic duct of the digestive diverticula. These findings implied its possible role in calcium absorption and transportation. In vivo, PFAP could be specifically released by phosphatidylinositol-specific phospholipase C (PIPLC), suggesting it is glycophosphatidylinositol-anchored to the plasma membrane. Therefore, a human growth hormone-PFAP fusion was constructed to locate the cleavage/attachment site. Immunofluorescent labeling and immunoblotting showed that Asn-477 is the cleavage/attachment site and the 25-residue peptide COOH-terminal to Asn-477 is removed during glycophosphatidylinositol anchoring. This research will hopefully pave the way to illustrate the role PFAP plays in calcium transportation related to pearl biomineralization.

Optimized preparation of daidzein-loaded chitosan microspheres and in vivo evaluation after intramuscular injection in rats.

A spherical symmetric design-response surface methodology was applied to optimize the preparation of daidzein-loaded chitosan microspheres by the emulsification/chemical cross-linking technique. The influence of polymer concentration, ratio of drug to polymer, and the stirring speed on the encapsulation efficiency, particle size, particle size distribution, and accumulative drug release percent in microspheres were evaluated. Scan electron microscopy of the optimized microspheres showed spherical particles, loading with drug microcrystal uniformly on the surface of and inside the microspheres. In vivo pharmacokinetic characteristics were evaluated after intramuscular injection of the microspheres in rats. The time-resolved fluoroimmunoassay method was used to determine plasma concentrations of daidzein. The data showed that the release of daidzein in the microspheres in vitro and in vivo almost lasted for 35 days. The bioavailability of daidzein in the microspheres by intramuscular injection increased up to 39% in rats, suggesting that the cross-linked chitosan microspheres are a valuable system for the long-term delivery of isoflavones.

Inhibition of cell growth and induction of G1-phase cell cycle arrest in hepatoma cells by steroid extract from Meretrix meretrix.

In this study, we report that the steroid extract 5alpha, 8alpha-epidioxycholest-6-ene-3beta-ol (MME) from Meretrix meretrix has the ability to inhibit growth of hepatoma cells and to induce G1-phase cell cycle arrest in two human hepatoma cell lines, HepG2 and Hep3B. HepG2 cells were more sensitive than Hep3B to MME. The extract markedly up-regulated the expression of p53 and p21WAF1/CIP1 in HepG2, suggesting that MME-induced G1 phase cell cycle arrest in HepG2 might be p53-dependent. Therefore, the up-regulation of p27KIP1and p16INK4A in both cell lines indicates that a p53-independent pathway might be involved in the mechanism of MME inducing cell cycle arrest. In conclusion, MME induces G1 phase cell cycle arrest via both p53-dependent and p53-independent pathways.

The effects of oridonin on cell growth, cell cycle, cell migration and differentiation in melanoma cells.

Oridonin, a diterpenoid isolated from Rabdosia rubescens (Hemsl.) Hara, is currently one of the most important traditional Chinese herbal medicines. We investigated the anti-proliferation effect of oridonin on the cultured murine melanoma cell line K1735M2. The growth inhibition activity of oridonin for K1735M2 cells occurred in a time- and dose-dependent manner (IC50 was 7.4+/-0.6 microM). Further studies showed that these inhibition effects were associated with dose-dependent G2/M phase arrest and differentiation induction. Detection of morphological observation showed that oridonin could induce K1735M2 cells to produce dendrite-like structures. The results of the migration indicated that oridonin affected motility of K1735M2 cells in a dose-dependent manner. These results suggested that oridonin is a potential candidate for melanoma cancer therapy.

[The effect of alendronate on arterial calcification in rat model].

OBJECTIVE: To study the effect of alendronate on artery calcification in rats. METHODS: (1) 4-week SD male rats were randomly divided into 3 groups: alendronate group (AL, n = 6), calcification group (CA, n = 6) and normal group (N, n = 6). In AL and CA group, artery calcification of rat was established by subcutaneous injection of vitamin D3 (300,000 U x kg(-1) x d(-1) for 3 days) and Warfarin (15 mg x 100 g(-1) x 12 h(-1) for 4 days); In AL group, at 4 days before establishment of artery calcification, alendronate (1 mg x kg(-1) x 24 h(-1)) was administered with subcutaneous injection and continued to be given to the end of the study. Abdominal aortae were collected for paraffin section and stained with von Kossa staining to observe the area of calcification. (2) Rat aortic vascular smooth muscle cells (VSMC) were cultured in vitro with tissue explant. All cells were divided into 5 groups: normal group, calcification group (control group), and alendronate 10(-9), 10(-7) and 10(-5) mol/L group. Before inducing calcification, alendronate 10(-9), 10(-7) and 10(-5) mol/L group were individually pre-treated with final concentrations of 10(-9), 10(-7) and 10(-5) mol/L alendronate for 24 hours. Beta-glycerophosphate were then added in the calcification group and in all the alendronate groups to induce VSMC calcification. All cells were cultured for 14 days. Cell crawling slice was applied to Alizarin red S staining to observe VSMC calcification. Colorimetric method was applied to measure the contents of Ca2+, cell proteins, and ALP activity. The ratio of contents of Ca2+ and cell proteins was cell calcium deposits. Cell proliferation was measured with tetrazolium salt (MTT) method. RESULTS: (1) With von Kossa staining the black deeply stained structure was found to be decreased in AL group. (2) As compared with the control group, in all the alendronate groups, showed that the number of calcium nodules [(6.8 +/- 2.7, 6.2 +/- 4.2, 5.3 +/- 2.4) % vs (7.4 +/- 3.8)%], and cell calcium depositions [(5.2 +/- 1.2, 4.8 +/- 1.7, 3.5 +/- 1.8)% vs (5.6 +/- 1.6)%], cell ALP activity and cell proliferation decreased significantly and dose-dependently. CONCLUSION: Alendronate can inhibit the artery calcification in rats.

[Effect of nanoparticle with vascular endothelial growth factor gene transferred into ischemic myocardium: experiment with rabbits].

OBJECTIVE: To evaluate the possibility and efficiency of nanoparticle as a new vector in vascular endothelial growth factor (VEGF) gene transference, and investigate the efficacy of direct gene transfer of nanoparticle with VEGF(165) gene into ischemic myocardium. METHODS: Nanoparticle-VEGF (Np/VEGF) complex was prepared with poly (D, L-lactide-co-glycolide) (PLGA) loading VEGF(165) gene and the envelopment efficiency and size of the complex were determined. The Np/VEGF was transfected into the cultured myocardial cells, RT-PCR and ELISA were used to evaluate the transfection of VEGF. Suspension of Np/VEGF was injected into the myocardial tissue of 4 rabbits. 96 hours after operation myocardial tissue was obtained, made into sections, and observed with electron microscope. New Zealand White rabbits underwent thoracotomy followed by ligation of left anterior descending coronary artery to establish ischemic models. The New Zealand White rabbits were divided into 3 groups: Np/VEGF group (n = 12, nanoparticle with VEGF(165) were injected into the cordial myocardium), blank plasmid group (n = 12, injected with blank VEGF(165) plasmid), and control group (n = 8, injected with normal saline). Ultrasonography and immunohistochemistry with factor VIII related antigen were conducted to evaluate the cardiac function and the collateral circulation of the occluded artery. One month later the rabbits were killed to observe the vascularization of capillaries in the ischemic myocardium. RESULTS: The envelopment efficiency of the Np/VEGF complex thus prepared, 50 - 300 nm in size, were 1.87% y. RT-PCR and ELISA showed that VEGF gene had been successfully transfected into myocardial cells by the nanoparticles. A great number of nanoparticles were observed in the myocardial cytoplasm and nuclei. One month after operation, the ventricular wall motor amplitude of the Np/VEGF group was 1.87 mm +/- 0.32 mm, significantly larger than those of the blank plasmid group (1.59 mm +/- 0.24 mm, P < 0.05) and control group (0.93 mm +/- 0.40 mm, P < 0.05); and the left ventricular ejection fraction of the Np/VEGF group was 60% +/- 10%, significantly higher than those of the blank plasmid group (50% +/- 6%, P < 0.05) and control group (40% +/- 8%, P < 0.05). The capillary density at low power field (x 100) of the Np/VEGF group was 57 +/- 12, significantly higher than those of the VEGF group (41 +/- 14) and control group (24 +/- 8). CONCLUSION: Nanoparticle can act as a vector to transfect specific gene in vitro and in vivo. Direct gene transfer of nanoparticle with DNA encoding VEGF into the ischemic rabbit myocardium can increase capillary number; therefore it may be a novel therapeutic approach for myocardial ischemia.

[Preparation of inclusion complex of daidzein and hydropropyl-beta-cyclodextrin].

OBJECTIVE: To prepare an inclusion complex of daidzein and hydropropyl-beta-cyclodextrin to enhance the solubility of daidzein. METHOD: The inclusion complex of daidzein was prepared by the solution stirring method. The binary system of daidzein and HP-beta-CD was confirmed by differential thermal, thermogravimetry analysis, infrared spectroscopy and X-ray diffractometry. RESULT: The drug content in the inclusion complex was 6. 76% and the solubility was 13.68 mg x mL(-1). The identification results showed that the inclusion complex was formed. CONCLUSION: The preparation method of the inclusion complex of daidzein and hydropropyl-beta-cyclodextrin is simple and available, with a increased solubility of daidzein.

Identification and Characterization of the Lysine-Rich Matrix Protein Family in Pinctada fucata: Indicative of Roles in Shell Formation.

Mantle can secret matrix proteins playing key roles in regulating the process of shell formation. The genes encoding lysine-rich matrix proteins (KRMPs) are one of the most highly expressed matrix genes in pearl oysters. However, the expression pattern of KRMPs is limited and the functions of them still remain unknown. In this study, we isolated and identified six new members of lysine-rich matrix proteins, rich in lysine, glycine and tyrosine, and all of them are basic matrix proteins. Combined with four members of the KRMPs previously reported, all these proteins can be divided into three subclasses according to the results of phylogenetic analyses: KRMP1-3 belong to subclass KPI, KRMP4-5 belong to KPII, and KRMP6-10 belong to KPIII. Three subcategories of lysine-rich matrix proteins are highly expressed in the D-phase, the larvae and adult mantle. Lysine-rich matrix proteins are involved in the shell repairing process and associated with the formation of the shell and pearl. What's more, they can cause abnormal shell growth after RNA interference. In detail, KPI subgroup was critical for the beginning formation of the prismatic layer; both KPII and KPIII subgroups participated in the formation of prismatic layer and nacreous layer. Compared with different temperatures and salinity stimulation treatments, the influence of changes in pH on KRMPs gene expression was the greatest. Recombinant KRMP7 significantly inhibited CaCO3 precipitation, changed the morphology of calcite, and inhibited the growth of aragonite in vitro. Our results are beneficial to understand the functions of the KRMP genes during shell formation.

Chemical modification studies on alkaline phosphatase from pearl oyster (Pinctada fucata): a substrate reaction course analysis and involvement of essential arginine and lysine residues at the active site.

Alkaline phosphatases (ALP, EC 3.1.3.1) are ubiquitous enzymes found in most species. ALP from a pearl oyster, Pinctada fucata (PALP), is presumably involved in nacreous biomineralization processes. Here, chemical modification was used to investigate the involvement of basic residues in the catalytic activity of PALP. The Tsou's plot analysis indicated that the inactivation of PALP by 2,4,6-trinitrobenzenesulfonic acid (TNBS) and phenylglyoxal (PG) is dependent upon modification of one essential lysine and one essential arginine residue, respectively. Substrate reaction course analysis showed that the TNBS and PG inactivation of PALP followed pseudo-first-order kinetics and the second-order inactivation constants for the enzyme with or without substrate binding were determined. It was found that binding substrate slowed the PG inactivation whereas had little effect on TNBS inactivation. Protection experiments showed that substrates and competitive inhibitors provided significant protection against PG inactivation, and the modified enzyme lost its ability to bind the specific affinity column. However, the TNBS-induced inactivation could not be prevented in presence of substrates or competitive inhibitors, and the modified enzyme retained the ability to bind the affinity column. In a conclusion, an arginine residue involved in substrate binding and a lysine residue involved in catalysis were present at the active site of PALP. This study will facilitate to illustrate the role ALP plays in pearl formation and the mechanism involved.

Measurement of genome-wide DNA methylation predicts survival benefits from chemotherapy in non-small cell lung cancer.

PURPOSE: Novel molecular predictive biomarkers for chemotherapy have been screened and validated in non-small cell lung cancer (NSCLC). However, there was no report on the correlation of genome-wide DNA methylation with survival benefit from chemotherapy in NSCLC. METHODS: A sandwich enzyme-linked immunosorbent assay (ELISA) method was first established, optimized and validated. A total of 191 NSCLC samples were analyzed using the sandwich ELISA for the association between the relative genome-wide DNA methylation level and the survival outcomes from chemotherapy. RESULTS: The analytical performance of the sandwich ELISA method was satisfying and suitable for analysis. Using the sandwich ELISA method, we found that the genome-wide DNA methylation level in NSCLC cancer tissues was significantly lower than that in adjacent normal tissues, which further validated the assay. We found that there was no significant correlation between genome-wide DNA methylation level and patients' histology, stage and progression free survivals. However, in patients with high methylation level, those without chemotherapy had significantly better overall survival than those receiving chemotherapy. In patients receiving chemotherapy, those with low genome-wide DNA methylation level had significantly better overall survival than those with relatively high DNA methylation level. CONCLUSIONS: Genome-wide DNA hypomethylation as a sign of genomic instability may predict overall survival benefit from chemotherapy in NSCLC.

Inhibitory effects of cupferron on the monophenolase and diphenolase activity of mushroom tyrosinase.

Mushroom tyrosinase (EC 1.14.18.1) is a copper containing oxidase that catalyzes both the hydroxylation of tyrosine into o-diphenols and the oxidation of o-diphenols into o-quinones. In the present study, the kinetic assay was performed in air-saturated solutions and the kinetic behavior of this enzyme in the oxidation of L-tyrosine and L-DOPA has been studied. The effects of cupferron on the monophenolase and diphenolase activity of mushroom tyrosinase have been studied. The results show that cupferron can inhibit both monophenolase and diphenolase activity of mushroom tyrosinase. The lag phase of tyrosine oxidation catalyzed by the enzyme was obviously lengthened and the steady-state activity of the enzyme decreased sharply. Cupferron can lead to reversible inhibition of the enzyme, possibly by chelating copper at the active site of the enzyme. The IC(50) value was estimated as 0.52 microM for monophenolase and 0.84 microM for diphenolase. A kinetic analysis shows that the cupferron is a competitive inhibitor for both monophenolase and diphenolase. The apparent inhibition constant for cupferron binding with free enzyme has been determined to be 0.20 microM for monophenolase and 0.48 microM for diphenolase.

Daidzein enhances osteoblast growth that may be mediated by increased bone morphogenetic protein (BMP) production.

Daidzein, a natural isoflavonoid found in Leguminosae, has received increasing attention because of its possible role in the prevention of osteoporosis. In the present investigation, primary osteoblastic cells isolated from newborn Wistar rats were used to investigate the effect of this isoflavonoid on osteoblasts. Daidzein (2-50 microM) increased the viability (P<0.05) of osteoblasts by about 1.4-fold. In addition, daidzein (2-100 microM) increased the alkaline phosphatase activity and osteocalcin synthesis (P<0.05) of osteoblasts by about 1.4- and 2.0-fold, respectively. Alkaline phosphatase and osteocalcin are phenotypic markers for early-stage differentiated osteoblasts and terminally differentiated osteoblasts, respectively. Our results indicated that daidzein stimulated osteoblast differentiation at various stages (from osteoprogenitors to terminally differentiated osteoblasts). We also investigated the effect of daidzein on bone morphogenetic protein (BMP) production in osteoblasts that display the mature osteoblast phenotype. The results indicated that BMP2 synthesis was elevated significantly in response to daidzein (the mRNA increased 5.0-fold, and the protein increased 7.0-fold), suggesting that some of the effects of daidzein on the cell may be mediated by the increased production of BMPs by the osteoblasts. In conclusion, daidzein has a direct stimulatory effect on bone formation in cultured osteoblastic cells in vitro, which may be mediated by increased production of BMPs in osteoblasts.

Expression of gonadotropin-releasing hormone receptor and effect of gonadotropin-releasing hormone analogue on proliferation of cultured gastric smooth muscle cells of rats.

AIM: To investigate the expression of gonadotropin-releasing hormone (GnRH) receptor and the effects of GnRH analog (alarelin) on proliferation of cultured gastric smooth muscle cells (GSMC) of rats. METHODS: Immunohistochemical ABC methods and in situ hybridization methods were used to dectect protein and mRNA expression of GnRH receptor in GSMC, respectively. Techniques of cell culture, OD value of MTT test, measure of (3)H-TdR incorporation, average fluorescent values of proliferating cell nuclear antigen (PCNA) and flow cytometric DNA analysis were used in the experiment. RESULTS: The cultured GSMC of rats showed immunoreactivity for GnRH receptor; positive staining was located in cytoplasm. GnRH receptor mRNA hybridized signals were also detected in cytoplasm. When alarelin (10(-9), 10(-7), 10(-5) mol/L) was administered into the medium and incubated for 24 h, OD value of MTT, (3)H-TdR incorporation and average fluorescent values of PCNA all decreased significantly as compared with the control group (P<0.05). The maximum inhibitory effect on cell proliferation was achieved a concentration of 10(-5) mol/L and it acted in a dose-dependent manner. Flow cytometric DNA analysis revealed that alarelin could significantly enhance ratio of G(1) phase and decrease ratio of S phase of GSMC of rats (P<0.05). The maximum inhibitory effect on ratio of S phase was at the concentration of 10(-5) mol/L and also acted in a dose-dependent manner. CONCLUSION: Our data suggest that GnRH receptor can be expressed by GSMC of rats. GnRH analogue can directly inhibit proliferation and DNA synthesis of rat GSMC through GnRH receptors.