简介:AIM:Toinvestigatethepossiblerelationshipbetweentheinfluencingfactorsoccurringbeforeandduringbirthinfull-terminfantsandtheoutcomeofretinopathy.·METHODS:Totally816full-terminfantsadmittedintheneonateintensiveunitofBoaiHospitalofZhongshanbetween1May,2008and30June,2011wereincludedinthestudy.Fundusexaminationwasperformedandevaluatedindividuallyonthemattheageof48hoursafterdelivery,2weeksand1month.Somepossibleriskfactorshappeningprenatallyorduringdeliverysuchaspregnantrelatedhypertension,placentaprevia,placentalabruptionetc,aswellassomeneonatalriskfactorssuchasneonatalasphyxia,hypoxic-ischemicencephalopathy(HIE),lowbirthweightetc,wererecordedandevacuated.Thentheeffectoftheriskfactorsoffull-terminfantsonretinopathywasstudied.·RESULTS:Theincidenceofretinalhemorrhageoffull-terminfantswithprenatalpregnantrelatedhypertension(PRH)ofthemother(43.6%)wassignificantlyhigherthanthatoffull-terminfantswithout(8.0%).(P<0.001).Theincidenceofretinalhemorrhageoffull-terminfantswithneonatalasphyxiaand/orhypoxic-ischemicencephalopathy(HIE)(29.3%)wassignificantlyhigherthanthatofthosewithout(15.7%),butcorrelationwasnotfoundbetweentheseverityofretinahemorrhageandthedegreeofhypoxicdisease.Apalecolorofopticdiscwasassociatedwithalowbirthweightoffull-terminfant.Full-terminfantswithbirthweighlessthan2500ghadasignificanthigherincidenceofretinopathythanthosewithbirthweightequalormorethan2500g(P<0.001).·CONCLUSION:Themaininfluencingfactorswhichleadtoretinopathyofhighriskfull-terminfantsareprenatalfactorssuchasPRH,andsomeneonatalriskfactorssuchasasphyxia,hypoxic-ischemicencephalopathy,andlowbirthweight.
简介:AIM:Tocomparetheeffectoftopicallyadministeredandsubconjunctivallyinjectedbevacizumabonexperimentalcornealneovascularizationinratsfortwoweeksaftertreatment.METHODS:Twenty-eightSprague-Dawleyratsweredividedintofourgroupsof7animals.Eachcornealcenterofrighteyewascauterizedwithsilver/potassiumnitratefor8s.Aftercornealburning,bevacizumab(12.5mg/mL)wastopicallyadministeredthreetimesperday(TBgroup)fortwoweeksorsubconjunctivallyinjectedondays2and4aftercauterization(0.02mL;SBgroup).Asnegativecontrols,ratsreceived0.9%salinetopicallythreetimesperday(TSgroup)orsubconjunctivallyondays2and4(0.02mL;SSgroup).Digitalphotographsofthecorneaweretaken1and2weeksaftertreatmentandanalyzedtodeterminetheareaofcorneacoveredbyneovascularizationasthepercentageofcornealneovascularization.RESULTS:Oneweekaftertreatment,thepercentageofcornealneovascularizationwassignificantlylowerintheTBandSBgroupsthanintheTSandSSgroups(allP<0.05).Twoweeksaftertreatment,thepercentageofcornealneovascularizationwassignificantlylowerintheTBgroupthanintheTSgroup(P<0.05).Inallgroups,thepercentageofneovascularizationwasdecreasingastimepassed(allP<0.05)CONCLUSION:Topicallyadministeredbevacizumabhaslongerstandinganti-angiogeniceffectthansubconjunctivallyinjectedbevacizumabincornealneovascularizationfollowingchemicalinjuryinrats.
简介:AIM:Tofindouttheoutcomeoflaserphotocoagulationinclinicallysignificantmacularedema(CSME)byopticalcoherencetomography(OCT).·METHODS:Itwasaprospective,non-controlled,caseseriesstudyenrolling81eyesof64patientswithCSMEbetweenAugust2008andJanuary2010.AllpatientsreceivedmodifiedgridphotocoagulationwithfrequencydoubledNd:YAGlaser.Eachpatientwasevaluatedintermsofbest-correctedvisualacuity(BCVA)andregressionorprogressionofmaculopathyafterlasertherapyat1,3and6months.Spearman’scorrelationtestwasusedtoshowthecorrelationbetweenBCVAandtotalmacularvolume(TMV).Analysisofvariance(ANOVA)wasusedtocompareamonggroupsandindependentt-testwasusedtocompareineachgroup.·RESULTS:ThereishighcorrelationbetweenBCVAandTMV(P≤0.001).BCVAimprovedin50.6%,remainedstaticin39.5%anddeterioratedin9.9%patientsafter6monthoftreatment.TheBaselineTMV(meanandSD)were9.26±1.83,10.4±2.38,11.5±3.05,8.89±0.75and9.47±1.98mm3fordifferentOCTpatterns,ST(spongelikethickening),CMO(cystoidmacularedema),SFD(subfovealdetachment),VMIA(Vitreomacularinterfaceabnormality)andaverageTMVrespectively(P=0.04).After6monthsoflasertreatment,themeanTMVdecreasedfrom9.47±1.98mm3to8.77±1.31mm3(P=0.01).InSTtherewassignificantdecreaseinTMV,P=0.01,Furtherwithinthesegroupsat6months,theyweresignificantlydifferent,P=0.01.·CONCLUSION:OCTshowedthedifferentmorphologicalvariantofCSMEwhiletheresponseoftreatmentisdifferent.TMVdecreasedthemostandhenceshowedtheimprovementinvisionafter6monthsoflasertreatment.IntheeraofAntivascularendothelialgrowthfactors(VEGFs),efficacyoflaserseemstobeinshadowbutitisstillfirstlineoftreatmentindevelopingnationlikeNepalwhereantiVEGFsmaynotbeeasilyavailableandaffordable.
简介:Simulationcanbedefinedasmalingering,orsometimesfunctionalvisualloss(FVL).Itmanifestsaseithersimulatinganophthalmicdisease(positivesimulation),ordenialofophthalmicdisease(negativesimulation).Consciousbehaviorandcompensationorindemnityclaimsareprominentfeaturesofsimulation.Sincesomeauthorssuggestthatthisisamanifestationofunderlyingpsychopathology,evenconversionisincludedinthiscontext.Intoday’sworld,everyophthalmologistcanfacewithsimulationofophthalmicdiseaseordisorder.Incaseofsimulationsuspect,thephysician’sresponsibilityistoprovethesimulationconsideringthedisease/disorderfirst,andsimulationasanexclusion.Insimulationexaminations,thephysicianshouldbefirmandsmarttoselectappropriatetest(s)toconvincenotonlythesubject,butalsothejudgeincaseofindemnityorcompensationtrials.Almostallophthalmicsensoryandmotorfunctionsincludingvisualacuity,visualfield,colorvisionandnightvisioncanbethesubjectofsimulation.Examinermustbeskillfulinselectingthemostappropriatetest.Apartfromthoseintheliterature,weincludedallkindsofsimulationinophthalmology.Inaddition,simulationexaminationtechniques,suchas,useofOCT(opticalcoherencetomography),frequencydoublingperimetry(FDP),andmodifiedpolarizationtestswerealsoincluded.Inthisreview,wemadeathoroughliteraturesearch,andaddedourexperiencestogivethereadersup-to-dateinformationonmalingeringorsimulationinophthalmology.
简介:AIM:ToinvestigatethesideeffectsofthecommonlyusedlasertreatmentalongwithtestingtheneuroprotectiveeffectofbFGFonapotentialretinalimpairment.METHODS:Todothis,30chinchillapigmentedadultmalerabbitsweredividedintothecontrolandexperimentalgroups.ThecontrolandexperimentalgroupsunderwentbothlaserapplicationandbFGFtreatment.Theretinaltissueimpairmentanditsrenewalrateweretestedunderthelightandelectronmicroscopicallevels.RESULTS:Thefocallaserapplicationonrabbiteyescausedmorphologicalalterationsbothintheapplicationregionandintheneighbouringareas.Inthedamagedareas,theouternuclearlayeroftheneuralretinawasalmostdisappeared,retinapigmentepitheliumwasinterrupted,theretinapigmentepitheliummigratedintraretinally,andthedamagedregionalongwithneighbouringareasseemedtobenotseparated.bFGFapplicationjustafterthelaserphotocoagulation,revealedbetterresultsinapplicationareas.CONCLUSION:ItcouldbesuggestedthatthebFGFapplicationfollowinglaserphotocoagulationmighthaveprotective,repairingandwoundhealingeffectsontheretina.
简介:AIM:ToinvestigatetheroleofRho-associatedproteinkinase(ROCK)inhibitor,Y27632,inmediatingtheproductionofextracellularmatrix(ECM)componentsincludingfibronectin,matrixmetallo-proteinase-2(MMP-2)andtypeIcollagenasinducedbyconnectivetissuegrowthfactor(CTGF)ortransforminggrowthfactor-β(TGF-β)inahumanretinalpigmentepithelialcellline,ARPE-19.METHODS:TheeffectofY27632ontheCTGForTGF-βinducedphenotypeinARPE-19cellswasmeasuredwithimmunocytochemistryasthechangeinF-actin.ARPE-19cellsweretreatedwithCTGF(1,10,100ng/mL)andTGF-β(10ng/mL)inserumfreemedia,andanalyzedforfibronectin,laminin,andMMP-2andtypeIcollagenbyRT-qPCRandimmunocytochemistry.CellswerealsopretreatedwithanROCKinhibitor,Y27632,toanalyzethesignalingcontributingtoECMproduction.·RESULTS:TreatmentofARPE-19cellsinculturewithTGF-βorCTGFinducedanECMchangefromacobblestonemorphologytoamoreelongatedswirlpatternindicatingamesenchymalphenotype.RT-qPCRanalysisanddifferentgeneexpressionanalysisdemonstratedanupregulationinexpressionofgenesassociatedwithcytoskeletalstructureandmotility.CTGForTGF-βsignificantlyincreasedexpressionoffibronectinmRNA(P=0.006,P=0.003respectively),lamininmRNA(P=0.006,P=0.005),MMP-2mRNA(P=0.006,P=0.001),COL1A1mRNA(P=0.001,P=0.001),COL1A2mRNA(P=0.001,P=0.001).PreincubationofARPE-19withY27632(10mmol/L)significantlypreventedCTGForTGF-βinducedfibronectin(P=0.005,P=0.003respectively),MMP-2(P=0.003,P=0.002),COL1A1(P=0.006,P=0.003),andCOL1A2(P=0.006,P=0.004)geneexpression,butnotlaminin(P=0.375,P=0.516).CONCLUSION:OurstudydemonstratedthatbothTGF-βandCTGFupregulatetheexpressionofECMcomponentsincludingfibronectin,laminin,MMP-2andtypeIcollagenbyactivatingtheRhoA/ROCKsignalingpathway.Duringthisprocess,ARPE-19cellswereshowntochangefromanepithelialtoamesenchymalphenotypeinvi
简介:AIM:Toevaluatetheaccuracyofsphericalequivalent(SE)estimatesofadouble-passsystemandtocompareitwithretinoscopy,subjectiverefractionandatablemountedautorefractor.METHODS:Non-cycloplegicrefractionwasperformedon125eyesof65healthyadults(age23.5±3.0years)fromOctober2010toJanuary2011usingretinoscopy,subjectiverefraction,autorefraction(AutokeratorefractometerTOPCONKR-8100,Japan)andadoublepasssystem(OpticalQualityAnalysisSystem,OQAS,VisiometricsS.L.,Spain).Nineconsecutivemeasurementswiththedouble-passsystemwereperformedonasubgroupof22eyestoassessrepeatability.ToevaluatethetruenessoftheOQASinstrument,theSElaboratorybiasbetweenthedoublepasssystemandtheothertechniqueswascalculated.RESULTS:TheSEmeancoefficientofrepeatabilityobtainedwas0.22D.SignificantcorrelationscouldbeestablishedbetweentheOQASandtheSEobtainedwithretinoscopy(r=0.956,P<0.001),subjectiverefraction(r=0.955,P<0.001)andautorefraction(r=0.957,P<0.001).ThedifferencesinSEbetweenthedouble-passsystemandtheothertechniquesweresignificant(P<0.001),butlackedclinicalrelevanceexceptforretinoscopy;Retinoscopygavemorehyperopicvaluesthanthedouble-passsystem-0.51±0.50Daswellasthesubjectiverefraction-0.23±0.50D;Moremyopicvalueswereachievedbymeansofautorefraction0.24±0.49D.CONCLUSION:Thedouble-passsystemprovidesaccurateandreliableestimatesoftheSEthatcanbeusedforclinicalstudies.Thistechniquecandeterminethecorrectfocuspositiontoassesstheocularopticalquality.However,ithasarelativelysmallmeasuringrangeincomparisonwithautorefractors(-8.00to+5.00D),andrequirespriorinformationontherefractivestateofthepatient.
简介:·Thisisacasepresentationofaverybizarreopenglobetraumawithanteriorsegmentforeignbody-fishinghookstuckinthecorneaandiris.Complicationsduetothiskindofeyetraumamightbeveryhazardousandwithseriousimpactonvisualfunction.Wearerepresentingourapproachandexperienceofthreestepmanagementofthiskindofeyeinjury:first-extracttheforeignbody,closeandreconstructtheeyeball,second-fightinflammation,andthird-restorethevisualfunctionbycataractsurgery.·
简介:AIM:ToevaluatethecornealendothelialcelldensityandmorphologyinChinesepatientswithpseudoexfoliationsyndrome(PEX).·METHODS:Medicalrecordsof16patients(20eyes)withPEXwhopresentedtoourinstitutionbetweenJuly2008andJune2010wereretrospectivelyreviewed.Thirteeneyeshadcombinedglaucoma.Theinformationoffiveapparentlynormalfelloweyesinthesepatientswasalsorecorded.Lefteyesof20patientswithbilateralsenilecataractsbutnoothereyediseasewereincludedascontrols.Specularmicroscopywasperformedinalleyestoanalyzeforcornealendothelialcelldensityandmorphology.Celldensity,coefficientofvariationincellsize,andpercentageofhexagonalcellsincornealendotheliumwereevaluated.·RESULTS:ThemeancornealendothelialcelldensityinthePEXeyeswas2298±239cells/mm2,significantlylowerthanthatinthecataracteyes(2652±18cells/mm2,P=0.026),buttherewerenosignificantdifferencesincoefficientofvariationofcellsizeandfrequencyofhexagonalitybetweenthesetwogroups.NosignificantdifferencesinthethreeparameterswerefoundbetweentheapparentlynormalfelloweyesandthePEXeyesorthecataracteyes,orbetweenthePEXeyeswithandwithoutglaucoma.·CONCLUSION:CornealendothelialcelldensitymaydecreaseinChinesepatientswithPEX.ThedevelopmentofglaucomainPEXeyesdoesnotseemtoberelatedwiththechangeincornealendothelialcelldensityormorphology.
简介:沙眼是由沙眼衣原体感染所致的一种传染性角结膜炎,目前在世界57个国家流行。1998年世界卫生组织(WorldHealthOrganization,WHO)将2020年全球消灭致盲性沙眼(globalalliancetoeliminateblindingtrachomaby2020,GET&nbsp;2020)列为其防盲工作的主要目标之一。世界卫生组织制定了辨认和命名沙眼的简化分级系统及以社区干预为基础的防治沙眼的SAFE策略,此后10余年各国对此策略进行了不断推广、执行,目前世界上沙眼的流行趋势较之此前有了一定的变化,我国也启动了“计划2016年前在中国根治致盲性沙眼”的防盲工作。本文就SAFE策略推广以来沙眼诊断、治疗及流行趋势等方面的进展做一综述。
简介:AIM:Toevaluatetheefficacy,safetyandstabilityofposteriorchamberphakicintraocularlensimplantationforthecorrectionofhighmyopia.METHODS:Retrospectivecasereviewof82eyes(43patients)undergoingimplantableColiamerlens(ICL)placementbyasinglesurgeon(Xiao-WeiGao)tocorrectpreoperativemeansphericalequivalentsbetween-9.00diopter(D)and-23.00D.Mainoutcomemeasuresincludeduncorrectedvisualacuity(UCVA),refraction,bestspectacle-correctedvisualacuity(BSCVA),endothelialcelldensity(ECD),intraocularpressure(IOP),lenstransparency,postoperativeuveitis.Visanteanteriorsegmentopticalcoherencetomography(AS-OCT)wasusedtomeasureanteriorchamberdepth(ACD)andthepositionofICL.RESULTS:Meanfollow-upwas6.54±3.26months(range3-12months).Predictabilityofthemanifestsphericalequivalent(SE)refractiontowithin±1.OODwasachievedin88%ofeyesand±0.50Din72.5%ofeyes.ThemeanpostoperativemanifestSErefractionwas-1.85±0.72D,with96.34%ofeyesmaintainingorgaining≥1line(s)ofBSCVA.Themean3-monthpostoperativeECDdecreasedbuthadnostatisticallydifferencecomparedwiththepreoperativeECD.Ofthe7eyes(8.54%)withamildtransientincreaseinintraocularpressure(upto30mmHg),nonerequiredasecondsurgicalprocedureorprolongedtopicalmedication.Therewasnolossoflenstransparency.Pigmentedprecipitateswereobservedin5eyes(6.09%).ThemeanpreoperativeACDmeasuredwithAS-OCTwas3.28±0.14mm,threemonthsaftersurgery,themeanACDwas2.45±0.22mm.Anteriorchamberdepthshowedastatisticallysignificantreduction.Oneeye(1.22%)hadICLspontaneousrotation,81eyes(98.78%)ofthelensremainedcorrectlycentered.CONCLUSION:TheimplantationofICLisaneffectivesurgicaloptionforthemanagementofhighmyopia.Butitslongtimeeffectandsafetystillneedmoretimetoprove.
简介:AIM:Todeterminewhethersinglenucleotidepolymorphism(SNP)rs641153isassociatedwiththeriskofage-relatedmaculardegeneration(AMD),weperformedasystematicmeta-analysisof15eligiblestudies.SNPinthecomplementfactorB(CFB)geneisconsideredtohavesignificantassociationwithAMDsusceptibility,butthereisgreatdiscrepancyintheseresults.METHODS:TheeligiblestudieswereidentifiedbysearchingthedatabasesofPubMed,EMBASE,andWebofScience.Oddsratios(ORs)with95%confidenceintervals(CIs)wereusedtoassesstheassociation.AlldatawereanalyzedusingStatasoftware.RESULTS:Theassociationbetweenrs641153andAMDriskwasstatisticallysignificantunderthehomozygousmodel(AAvsGG:OR=0.26,95%CI=0.15-0.45,P_h=0.973,/~2=0.0%,fixedeffects),dominantmodel(AA+GAvsGG:OR=0.49,95%CI=0.40-0.59,P_h=0.004,/~2=56.4%,randomeffects)andrecessivemodel(AAvsGA+GG:OR=0.30,95%CI=0.17-0.51,R_n=0.983,I~2=0.0%,fixedeffects).Thesameresultswerealsoobservedinthestratifiedanalysesbyethnicity,sourceofcontrolandsamplesize.CONCLUSION:Ourmeta-analysissuggeststhatrs641153intheCFBgenemayplayaprotectiveroleinAMDsusceptibility,thelateAMDinparticular,bothinCaucasiansandinAsians.
简介:AIM:ToIntroduceanewspecializedvisualacuitychartforamblyopicchildrenaged3-5yearsoldanditsclinicalapplications.METHODS:ThenewvisualacuitychartandnotationsweredesignedbasedonWeber-Fechnerlaw.Theoptotypeswereredagainstawhitebackgroundandwerespeciallyshapedfourbasicgeometricsymbols:circle,square,triangle,andcross.Aregulargeometricprogressionoftheoptotypesizesanddistributionwasemployedtoarrangein14lines.Theprogressionrateoftheoptotypesizebetweentwolineswas1.2589andthetestingdistancewas3m.VisualacuityscorecouldberecordedaslogMARnotationordecimalnotation.Agestratifieddiagnosticcriteriaforamblyopiaestablishedbyconsensusstatementondiagnosisofamblyopia(2011)amongmembersoftheStrabismusandPediatricOphthalmologyGroup,OphthalmologySociety,ChineseMedicalAssociation(SPOGOSCMA)wereillustratedinthenewvisualacuitychart.RESULTS:Whenassessingvisualacuityinchildrenaged3-5yearsold,thisnewvisualacuitychartthatconsistsoffoursymmetricalshapes(triangle,square,cross,andcircle)overcameaninabilitytorecognizethelettersofthealphabetanddifficultiesindesignatingthedirectionofblackabstractsymbolssuchasthetumbling’E’orLandolt’C’,whichthesubjectswerepronetoloseinterestin.Thevisualacuityscoremayberecordedindifferentnotations:decimalacuityandlogMAR.Thesetwonotationscanbeeasilyconvertedeachotherintheneweyechart.Themeasurementsofthisnewchartnotonlyshowedasignificantcorrelationandagoodconsistencywiththeinternationalstandardlogarithmicvisualacuitychart(r=0.932,P<0.01),butalsoindicatedahightest-retestreliability(89%ofretestscoreswerewithin0.1logMARunitsoftheinitialtestscore).CONCLUSION:Theresultsofthisstudysupportthevalidityandreliabilityofdistancevisualacuitymeasurementsusingtheneweyechartinchildrenaged3to5yearsoverawiderangeofvisualacuities,andtheneweyechartisgreatforearl
简介:Endogenousaspergillusendophthalmitis(EAE)afterkidneytransplantisararebutimportantclinicalproblemduetopotentiallydevastatingconsequences.EarlydiagnosisofEAE,timelyremovalofaffectedvitreousbyvitrectomy,properanti-fungaltreatment,allcontributedtothesuccessfulcontrolofthedisease.TherapeuticsuccessofEAEinpost-transplantpatientsdependslargelyonpromptdiagnosis.DefinitediagnosisofEAEisbasedonpositivecultureresultsofvitreousspecimen,whilefundoscopyandBscanultrasoundmayaidearlydiagnosis.Intermsofanti-fungalmedicine,amphotericinBhaslongbeenthefirstchoice,butitssystemicapplicaitonhassevereadversereactions,especiallyforpatientswithimpairedrenalfunction.Herein,wereportthetreatmentmodalityofEAEafterkidneytransplantwithvitrectomy,systemicadministrationofmicafunginplusvoriconazole,topicalapplicationoffluconazolandamphotercinB.
简介:AIM:Toinvestigatewhether15-Lipoxygenase-1(15-LOX-1)playsanimportantroleintheregulationofangiogenesis,inhibitinghypoxia-inducedproliferationofretinalmicrovascularendothelialcells(RMVECs)andtheunderlyingmechanism.METHODS:PrimaryRMVECswereisolatedfromtheretinasofC57/BL6JmiceandidentifiedbyanevaluationforFITC-markedCD31.ThehypoxiamodelswereestablishedwiththeBio-bagandevaluatedwithablood-gasanalyzer.ExperimentswereperformedusingRMVECstreatedwithandwithouttransferAd-15-LOX-1orAd-vectorbothunderhypoxiaandnormoxiaconditionat12,24,48,72hours.Theefficacyofthegenetransferwasassessedbyimmunofluorescencestaining.CellsproliferationwasevaluatedbytheCCK-8method.RNAandproteinexpressionsof15-LOX-1,VEGF-A,VEGFR-2,eNOsandPPAR-rwereanalyzedbyreal-timereversetranscriptionpolymerasechainreaction(RT-PCR)andWesternblot.RESULTS:RoutineevaluationforFITC-markedCD31showedthatcellswerepure.Theresultsofblood-gasanalysisshowedthatwhenthecultureswereexposedtohypoxiaformorethan2hours,thePo2was4.5to5.4Kpa.WeverifiedRMVECscouldbeinfectedwithAd-15-LOX-1orAd-vectorviaFluorescencemicroscopy.CCK-8analysisrevealedthattheproliferativecapacitiesofRMVECsinhypoxicgroupweresignificantlyhigherateachtimepointthantheywereinnormoxicgroup(P<0.05).Inahypoxiccondition,theproliferativecapacitiesofRMVECsin15-LOX-1groupweresignificantlyinhibited(P<0.05).Real-timeRT-PCRanalysisrevealedthattheexpressionsofVEGF-A,VEGF-R2andeNOsmRNAincreasedinhypoxiagroupcomparedwithnormoxiagroup(P<0.01).However,theexpressionsof15-LOX-1,PPAR-rmRNAdecreasedinhypoxiagroupcomparedwithnormoxiagroup(P<0.01).Italsoshowedthatinahypoxiccondition,theexpressionsofVEGF-A,VEGF-R2andeNOsmRNAdecreasedsignificantlyin15-LOX-1groupcomparedwithhypoxiagroup(P<0.01).However,15-LOX-1andPPAR-rmRNAincreasedsigni