[Risk factors of Schistosoma japonicum infection in Xingzi County].

OBJECTIVE: To explore the risk factors of Schistosoma japonicum infection in the residents in Xingzi County, Jiangxi Province. METHODS: Six administrative villages from different areas were randomly selected by the cluster sampling method as the study sites in Xingzi Country in 2013, and all the residents aged 5 years or above were investigated epidemiologically, and the schistosome infection was surveyed by Kato-Katz technique. The risk factors of schistosomiasis were analyzed by using the Chi-square test analysis and multivariate Logistic regression model. RESULTS: In 2013, there were 2 050 residents received the stool examination and 146 persons were positive, the schistosome infection rate was 7.1%. The Chi-square test showed that gender, age, occupation and education level were associated with the population infection rate (χ2 = 26.485、16.836、25.700、 90.805, all P < 0.05). The multivariate Logistic regression mode showed that the probability of schistosomiasis for the male was 3.041 times as much as that for the female; the probability of schistosomiasis for the illiteracy and primary education level crowd was 8.870 times as much as that for the college degree or above crowed; the probability of schistosomiasis for the junior middle school education level crowd was 5.598 times as much as that for the college degree or above crowed; the probability of schistosomiasis for the high school education level crowd was 2.995 times as much as that for the college degree or above crowed; the probability of infection of fishermen was the highest, which was 3.053 times as much as that for the other professional crowds. CONCLUSIONS: The risk factors of schistosome infection mainly include gender, occupation and the education level. We should strengthen the health education of schistosomiasis control, protection against the infested water contact, and so on.

microRNA-155 is downregulated in gastric cancer cells and involved in cell metastasis.

microRNA-155 (miR-155), an important multifunctional microRNA, has been implicated in the development of multiple solid tumors, yet, its role in gastric cancer cells has not been fully elucidated. In this study, we find that miR-155 was significantly downregulated in gastric cancer cell lines compared with an immortalized gastric epithelial cell line (GES-1). Overexpression of miR-155 in SGC-7901 and MKN-45 gastric cancer cells dramatically suppressed cell migration, invasion and adhesion in vitro. Overexpression of miR-155 significantly reduced the protein levels of SMAD2 and repressed the activity of a luciferase reporter containing one of the two predicted miR-155 binding sites in SMAD2 3'-UTR, indicating that SMAD2 may be a miR-155 target gene. miR-155 expression was also remarkably restored by a DNA demethylating agent (5-Aza-2-deoxycytidine) in SGC-7901 and MKN-45 gastric cancer cells. Taken together, these data suggest that miR-155 may function as a tumor suppressor to regulate gastric cancer cell metastasis by targeting SMAD2, and its downregulation in gastric cancer cells may be partly ascribed to DNA methylation.

[Effects of resveratrol on the proliferation and CaN of vascular smooth muscle cell induced by angiotensin II].

AIM: To investigate the effects of resveratrol (Res) on the proliferation of VSMCs induced by Ang I and the expression of calmodulin (CaM) and calcineurin (CaN) in the proliferation of VSMCs treated by Ang 1 and to discuss the mechanism. METHODS: Rabbit arterial VSMCs were cultured in vitro and VSMCs were identified with the method of immunocytochemistry. A cell proliferating model of VSMCs induced by AngII was established. VSMCs were cultured for 4-8 passages. The experiments were randomly divided into control group, AngII group (0.1 micromol/L) and AngII + Res groups with different concentrations(20, 40, 80, 160) micromol/L. VSMCs proliferation was determined with MTT colorimetric method. CaM was detected with Coomassie brilliant blue method and CaN was determined by enzyme reaction phosphorus measurement. RESULTS: Rabbit VSMCs were cultured successfully and could be passaged. After immunocytochemistry staining, all the cells cytoplasm were stained and positive. Cell proliferation, CaM and CaN activities were increased significantly in VSMCs proliferation induced by AngII (P <0.05, P < 0.01). The index of AngII + Res groups were obviously reduced compared with AngII group ( P < 0.01). CONCLUSION: The VSMCs proliferation induced by AngII can be inhibited by Res significantly, and the inhibiting mechanism of Res may be related to inhibiting CaM and CaN activities then restraining the proliferation of VSMCs in a dose dependent manner.

[Study on clinical efficacy and mechanism of xiaoyan zhixue capsule in treating menorrhagia caused by intrauterine device].

OBJECTIVE: To observe the efficacy of Xiaoyan Zhixue Capsule (XYZXC) in treating uterus abnormal menorrhagia caused by intrauterine device (IUD) and to study its mechanism. METHODS: IUD users with menorrhagia were randomly divided into two groups, the XYZXC treated group and adrenosoem (AC-17) control group. Endometrial tissue of XYZXC treated group before and after treatment were taken out to observe its morphologic change with optic and electronic microscope. Animal experiment was done to observe the effect of XYZXC in eliminating inflammation of patierts, and the relevant parameters were monitored. RESULTS: Clinical efficacy: (1) Total effective rate of the treated group was 90.3%, that of control group was 43.5%, comparison between them showed significant difference (P<0.01). (2) Morphological examination of endometrial tissue showed the inflammation in the treated group abated after treatment with the contractible function of helicine artery strengthened. Experimental study showed: (1) The auricular swelling of mice was inhibited by 40.5% in the treated group, the effect was equivalent to that of hydrocortisone (46.9%). (2) Compared with the control group, the plasma 6-keto-PGF1alpha and D-Dimer level in the treated group were markedly lower, and TXB2/6-keto-PGF1alpha ratio and plasma endothelin level were markedly higher (P<0.05 or P<0.01). ET contents in large dosage TCM group was significantly raised (P<0.05). (3) XYZXC could increase amplitude of contraction of the uterus smooth muscle as well as the uterus activity in rats in vivo. CONCLUSION: XYZXC has obvious anti-inflammatory and hemostatic effects, it has marked effect in treating IUD caused pre- and post-menstruation menorrhagia, the possible mechanism may be: (1) Modulating the synthesis of prostaglandin; (2) Antagonizing the IUD caused fibrinolytic hyperfunction; (3) Promoting the synthesis of ET; (4) Increasing the contractility and activity of uterus smooth muscle.

Transition state P-glycoprotein binds drugs and modulators with unchanged affinity, suggesting a concerted transport mechanism.

The P-glycoprotein multidrug transporter is a plasma membrane efflux pump for hydrophobic natural products, drugs, and peptides, driven by ATP hydrolysis. Determination of the details of the catalytic cycle of P-glycoprotein is critical if we are to understand the mechanism of drug transport and design ways to inhibit it. It has been proposed that the vanadate-trapped transition state of P-glycoprotein (Pgp x ADP x V(i) x M(2+), where M(2+) is a divalent metal ion) has a very low affinity for drugs compared to resting state protein, thus leading to binding of substrate on the cytoplasmic side of the membrane and release of substrate to the extracellular medium (or the extracellular membrane leaflet). We have used several different fluorescence spectroscopic approaches to show that isolated purified P-glycoprotein, when trapped in a stable transition state with vanadate and either Co(2+)or Mg(2+), binds drugs with high affinity. For vinblastine, colchicine, rhodamine 123, and doxorubicin, the affinity of the vanadate-trapped transition state for drugs was only very slightly (less than 2-fold) lower than the binding affinity of resting state Pgp, whereas for the modulators cyclosporin A and verapamil and the substrate Hoechst 33342, the binding affinity was very similar for the two states. The drug binding affinity of the ADP-bound form of the transporter was also comparable to that of the unoccupied transporter. These results suggest that release of drug from the transporter during the catalytic cycle precedes formation of the transition state.

Stoichiometry and affinity of nucleotide binding to P-glycoprotein during the catalytic cycle.

Drug transport mediated by P-glycoprotein (Pgp) is driven by hydrolysis of ATP at the two cytosolic nucleotide binding domains. However, little is currently known concerning the stoichiometry of nucleotide binding and how both stoichiometry and binding affinity change during the catalytic cycle of the transporter. To address this issue, we used fluorescence techniques to measure both the number of nucleotides bound to P-glycoprotein during various stages of the catalytic cycle and the affinity of nucleotide binding. Results showed that resting state P-glycoprotein bound two molecules of the fluorescent nucleotide derivative, 2'(3')-O-(2,4,6-trinitrophenyl)adenosine 5'-triphosphate (TNP-ATP), whereas the vanadate-trapped transition state bound only one nucleotide molecule. Both resting and transition state P-glycoprotein showed similar affinity for TNP-ATP/TNP-ADP and unlabeled ATP/ADP. Following binding of various drugs, resting state P-glycoprotein displayed a higher affinity for nucleotides, up to 4-fold depending on the compound used. In contrast, the transition state showed substantially lower (up to 3-fold) nucleotide binding affinity when the drug binding site(s) is/are occupied. These results indicate that both nucleotide binding domains of P-glycoprotein are likely to be occupied with either ATP (or ADP) in the resting state and the transition state in the absence of transport substrates. Drugs alter the binding affinity to favor association of ATP with P-glycoprotein at the start of the catalytic cycle and release of ADP from the transition state following nucleotide hydrolysis.

Proximity of bound Hoechst 33342 to the ATPase catalytic sites places the drug binding site of P-glycoprotein within the cytoplasmic membrane leaflet.

The P-glycoprotein multidrug transporter carries out ATP-driven cellular efflux of a wide variety of hydrophobic drugs, natural products, and peptides. Multiple binding sites for substrates appear to exist, most likely within the hydrophobic membrane spanning regions of the protein. Since ATP hydrolysis is coupled to drug transport, the spatial relationship of the drug binding sites relative to the ATPase catalytic sites is of considerable interest. We have used a fluorescence resonance energy transfer (FRET) approach to estimate the distance between a bound substrate and the catalytic sites in purified P-glycoprotein. The fluorescent dye Hoechst 33342 (H33342), a high-affinity P-glycoprotein substrate, bound to the transporter and acted as a FRET donor. H33342 showed greatly enhanced fluorescence emission when bound to P-glycoprotein, together with a substantial blue shift, indicating that the drug binding site is located in a nonpolar environment. Cys428 and Cys1071 within the catalytic sites of P-glycoprotein were covalently labeled with the acceptor fluorophore NBD-Cl (7-chloro-4-nitrobenz-2-oxa-1,3-diazole). H33342 fluorescence was highly quenched when bound to NBD-labeled P-glycoprotein relative to unlabeled protein, indicating that FRET takes place from the bound dye to NBD. The distance separating the bound dye from the NBD acceptor was estimated to be approximately 38 A. Transition-state P-glycoprotein with the complex ADP*orthovanadate*Co2+ stably trapped at one catalytic site bound H33342 with similar affinity, and FRET measurements led to a similar separation distance estimate of 34 A. Since previous FRET studies indicated that a fluorophore bound within the catalytic site was positioned 31-35 A from the interfacial region of the bilayer, the H33342 binding site is likely located 10-14 A below the membrane surface, within the cytoplasmic leaflet of the membrane, in both resting-state and transition-state P-glycoprotein.