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医学范文摘要

时间:2015-06-27 来源:未知 作者:致谢2号编辑 本文字数:4605字

  ABSTRACT

  (-)-Epigallocatechin gallate (EGCG) as one of ester catechins,which is a bioactive molecule, has been shown to possess varieties ofhealth functions such as antioxidant, anti-ultraviolet radiation andprotection against skin cancer, etc. However, the stability of EGCG underhuman pH environment is poor to cause a low bioavailability. Therefore,how to enhance bioavailability of EGCG is a hot issue at present Theethosome is a novel carrier for enhanced delivery in skin, which has beenreported to have productive advantages, such as high entrapping capacityand excellent skin permeation. It is potential to improve stability andbioavailability of drugs, if drugs are entrapped by ethosomes.

  In the present study, preparation method of nano~ethosomesentrapping EGCG was investigated and its improved effect onanti-ultraviolet radiation was checked.

  (1) The conditions of preparing nano-EGCG ethosomes wereinvestigated. By a combination of injecting and ultrasonic emulsificating,nano-ethosomes entrapping EGCG were successfully prepared. Theoptimum parameters for the preparation were obtained by the orthogonaltest. The results showed that 2% phospholipids and 30% ethanol forformation of ethosomes, 0.1% K9 and 1.0% Tween-80 as stabilizers, and0.25% EGCG as drug under ultrasonic processing for 2 min could yieldexcellent ethosomes with mean size 62.8nm, zeta potential -42.8mV andPDI (polydisperant index) 0.097. The entrapping efficiency of thenanoethosomes was more than 90%.

  (2)Skin permeation experiments were conducted by cnfocal laserscanning microscope (CLSM) using rodmine B as a fluorescence probe.The results showed that in terms of the transdermal depth of ethosomes,the EGCG nano-ethosomes could permeate deeper than the EGCGhydroethanolic solution, and the EGCG transdermal quantity byethosomes was obviously greater than that of the hydroethanolic solution.

  The transdermal delivery in vitro was studied by measurating the amountof EGCG in or through skin. For the EGCG nano-ethosomes the EGCGamount could reach 40.13jig ? cm“2 and 289.8路? cm”2 at 8h and 24htransdermal penetration while those of the EGCG hydroethanolic solutionwere only 18.26jxg? cm“2 and 35.67(ig ? cm*2.

  (3)The anti-ultraviolet-B (UVB) irradiation was tested by animalerxperiment with nude mice. After the mice were given UVB irradiationwith a total dose of 625 mJ/cm2, the skin tissue change was obsvered bylight microscope and TEM. The results demonslrated that EGCGnano-ethosomes could attenuate UVB-induced skin damage, and its effectwas clearly better than EGCG hydroethanolic solution.

  ABSTRACT

  In the statistical experiment, subjects may experience the outcome of interestmore than once, the event are called recurrent event and the observation of theseoutcomes are called repeated events data or recurrent event data. This type of dataarises in many fields such as medical field, public health, biology, demography andeconomics. To analyze recurrent event data, various models and approaches have beenproposed in the literature. The researches of recurrent events include the number ofevents up to the observation time, the event times and the inter-event times (gaps)。 Themodels and approaches for the number of events over times were studied by manyauthors. Generally, low dimensional covariates have been assumed in modelingrecurrent event data, but which may be violated in the analysis when the covariates arehigh-dimensional. In recent years, with the development of computers and otherinformation technology, the data and the covariates are more complex from the studiesof biology, medicine, ecology, demography, environment and economics and otherdisciplines. Some useful important information is often hidden behind thehigh-dimensional data. So, recently, the high-dimensional data regression is verypopular in many areas. Due to the ”dimension curse“ exists, many traditional statisticalmethods have encountered big challenges and unprecedented difficulties. Thus, in ourpaper, we discuss the dimension reduction approaches on the joint model of recurrentevent and terminal event with high-dimensional covariates to solve the dimensionreduction problems in recurrent event model.

  In our paper, the model we discussed is the joint model of the multiplicativehazard rate function of recurrent event and termination event. The innovation of thispaper is that we use the partial sufficient dimension reduction theory and method onthe joint model. We not only study the dimension reduction problem of the recurrentevent model, but also consider the dimension reduction problem of the terminal eventmodel. The application of the partial sufficient dimension reduction theory and methodon recurrent event model and the dimension reduction problem of terminal eventmodel are worthy to study and not to pay more attention in the literature. In this paper,we mainly focus on two aspects: The first aspect, to solve the dimension reductionproblem of the multiplicative hazard rate function of recurrent event model, first anonparametric estimator is proposed for the baseline function, and the basis of thepartial central subspace and its structural dimension are estimated through the partialsufficient dimension reduction. Based on the estimated structural dimension, the basisof the partial central subspace and the baseline, we can get the estimator of theregression function by using the local linear regression. The second aspect, based onthe frailty factor estimated from the multiplicative hazard rate model of the recurrentevent, we discuss the partial dimension reduction of the multiplicative hazard ratemodel of terminal event. Two methods are proposed in this paper, the first method: weuse the partial dimension reduction to get the estimator of the partial central subspaceand then we use the local partial likelihood function to get the estimators of thebaseline function and the regression function. The second method: the efficientestimation method is used to get the central subspace. For simplicity in calculation, weassume the baseline function is known in the terminal event model.

  A simulation is performed to conform and assess the theoretical findings, and anexample is also demonstrated on a set of chronic glaucomatous disease data.

  ABSTRACT

  ObjectiveThrough the establishment of an animal model of acute lung injury in paraquat poisonedrats,it can be observed that the effects of salidroside (SDS) on MMP-2, TIMP-1 of lung tissuein lung injured acute paraquat (PQ) poisoned rats, aiming to clarify the presence ofsalidroside's protective and anti-fibrosis function on lungs.

  Methods130 adult male SD rats were randomly divided into: normal group (NS group, 10); PQmodel group (60 were randomly divided into six subgroups, each 10 at Id, 3d, 7d,14d,21d,28d ); SDS intervention group (60 were randomly divided into six subgroups,each 10 at Id,3d, 7d,14d, 21d, 28d)。 Among which,the normal control group is gavaged with ImL salineonce, the PQ model group and the SDS intervention group were gavaged with the 20 mg / kgPQ diluted with ImL saline.

  Aafter paraquat poisoning lh, the SDS intervention group, was given dailyintraperitoneal injection of lOmg/kg Salidroside every 12hs . As for the NS control group andthe PQ model group, they were injected with saline with equal volumn to the SDS group,once every 12hs. The PQ model group and the SDS intervention group were taken specimensfrom the right lower lung tissue under anesthesia anatomical, after paraquat poisoning Id,3ds,7ds, 14ds, 2Ids, 28ds. Part of the specimens was stored in refrigerator at -70.C forRT-PCR and Real-time PCR testing,and the other part was rinsed in saline, fixed in 10%formalin,dehydrated,made transparent, dipped into wax. And the paraffin-embedded tissueblocks and the. slices, are for HE staining and immunohistochemical staining.

  ResultsCompared with the normal group, the rats in the PQ model group and the SDSintervention group got the early symptoms of acute lung inflammation, pulmonary edema andobvious bleeding. Changes in pulmonary fibrosis were observed after exposure to PQ for 7days and it came to the climax at 28th day; the SDS group got the similar symptoms, butwhich are relatively mild. In contrast, in the PQ group, the MMP-2 protein and mRNA areobviously and increasingly expressed in the lung tissue of rats from on the first day and tillthe 7th day it reached a peak,though declined slowly, still significantly higher than thenormal group at the 28th day; And the TIMP-1 protein expression also significantly enhancedfrom 1st d,reaching a peak at the 14th day, then remained high afterwards。

  Compared with the previous groups, the SDS intervention group kept a significantly lowerlevel at MMP-2 and TIMP-1 protein and mRNA expression (P <0.05)。

  Conclusion1,20 mg / kg paraquat gavage can successfully make animal models of acute lung injury;2, MMP-2, TIMP-1 in acute lung injury induced by paraquat poisoning and pulmonaryfibrosis plays an important role;3,Salidroside (SDS) can inhibit MMP-2, TIMP-1 mRNA expression and proteinexpression, and restore the balance between the previous two, thus delaying or even inhibitingthe fibrotic process.

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