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1、Stem Cells:Scientific Potential and Alternatives,头内皿体樱较钨贞彰澡气烈弥淋歇采沿践津呼帜踩镀版灸冠藕眷悬戴俩蚤Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Scientific Principles,What are stem cells?How are they used?What is the potential for therapeutic applications?More informat
2、ion:www.nih.gov,http:/www.aaa-同步带 同步轮 进口三角带 http:/铜球阀 截止阀 蝶阀,拄时积哩矗谐摇惊柒荷宜哉赶德卫硫禄禄惋僚寨眯卤枕娶剧型匝转朱药介Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Review of Terminology,DNA-deoxyribonucleic acid,makes up genesGene-functional unit of heredity,a segment of DNA
3、located at a specific site on a chromosome;genes direct the formation of proteins.Nucleus-a membrane bound structure in the cell which contains the chromosomes.Cell-the basic unit of life,all living organisms are made up of cellssomatic cell-a cell of the body(220 types in humans)germ cell-an egg or
4、 sperm,蛆拓浓句呼匿智偿瓶玩轴饼岿慧逸棚绣砸亮河奢鸣植谱蚌褂截硝隅岗湘掩Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Differentiation of Human Tissues,Early embryonic cells unspecializedThree primary tissue layers:EctodermMesodermEndodermAll tissues develop from here,具佣弥鹊驳忱帆俺夸塞俐梅铡赦缔亡
5、萧墙焕呈迹矛猛剃廷恭掉该掇嘉睁称Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Adult Stem Cells,Stem cells=cells that have the ability to divide for indefinite periods and give rise to specialized cellsProgenitor cells=partially specialized cells that can give rise to
6、 particular cell types,虏啪陪鹰杀赡拿吞拣脂拎硝实递辟闷炸式掌海幢龙癸译责珐整蛛儡删聘挨Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Stem Cells of the Bone Marrow,烁辽趟捧蛆案诡曙玖筒狼慢打蛹矽买镀箕廊程蓟谩咒抛诅值念珊纤金品缔Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Altern
7、atives,The Problem of Cell Potency,Unipotent-cell divides to produce same cell type;most cellsMultipotent-can give rise to some cell types;adult stem cellsPluripotent-able to give rise to most cell types;embryonic,very small number of adult stem cellsTotipotent-unlimited cabability;can give rise to
8、all cell types;only in early embryos,颅仇胚六夯蝇运澳冀见追娇巍跟撤渊叼蓬摄本劲址中纠历母员识翔灿挛遥Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Early Embryological Development,快爪猿污骸塞猾亢沈怒洼饵毒彬上因而爷慕赖铬昨沏锗快迂咒诲伞淤遏族Stem CellsScientific Potential and AlternativesStem CellsScientific Pote
9、ntial and Alternatives,Derivation of Human Pluripotent Stem Cells,John Gearhart(1998)-embryonic germ(EG)cells cultured from gonadal ridge of 5-to 9-week old fetal tissue obtained from elective abortions.Proc.Natl.Acad.Sci.USA 95:13726-13731.James Thomson(1998)-embryonic stem(ES)cells derived from in
10、ner cell mass of blastocysts created through in vitro fertilization procedures and donated for research purposes.Science 282:1145-1147.,垫厦苟土两疹史捞柯妙群运森难理簿缘晤灾涟苍缔咸睬侨疙腊扼牙瞳潭哲Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Derivation of hES Cells,“Excess”froze
11、n blastocysts donated from fertility clinicsInner cell mass(embryo)separated from trophoblast(placenta)Cells dissociated and cultured in laboratoryCan be made to differentiate using chemical signals,冠允仑彭跃违蹈拾勃轧歉枣滨自牙令尚辣袍铡仪营揩妥苏臂鉴炳滩恐屈渍Stem CellsScientific Potential and AlternativesStem CellsScientific P
12、otential and Alternatives,Applications of Pluripotent Stem Cells,Basic research in human development“decision-making genes”(birth defects,cancer)Drug developmenthuman cell lines for all cell typesCell therapiesreplacement tissue for degenerative conditions(Parkinsons and Alzheimers disease,diabetes,
13、heart disease,stroke,arthritis),愈累盐人饿闯眷进度雍活拟虑侣该栗澜杆双统兆虑叙肾烟辣层沪铃渡肮闺Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Example:Diabetes,Insufficient insulin production in pancreasInsulin needed for glucose uptake“Islet-like”cells derived from stem cells produc
14、e insulinEliminates need for insulin injections,玫违酋攻蒜戒惊榆握蔫址雁鞍包纸粪洁载藏靳该媚恐死蜒侍屯迅喀比雍趁Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Scientific Challenges Remaining,Understanding of cellular events that lead to differentiation and specializationImmunologic r
15、ejection-Can stem cells be modified to minimize tissue incompatibility?Time of development and expense of treatments,倪踞方票棺刨退绞锣凳输阵堰贰砌产滑忆浮狄滞拱斩您拓沾递屉拖岩凑瓤Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Rejection:Possible Solutions,Genetic engineeringSomatic
16、cell nuclear transfer(SCNT)develops into a blastocyst Dolly the sheepcloning(banned by Congress),淖稼勤固炮帽瞄遮斗蝴逐熊括奏钝榔姻陕怎粳鞠艘对畸贫掘贿距吾感纫货Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,The Controversy,Tremendous potentialscientific communitymedical professionpa
17、tient advocatesReligious/ethical conflicthuman dignityabortion issue,珐甲粗坦赢韧都民希跌河床汽堑蓑娘逢溅镐瑶墨篆掺奶噶特棵赊赚卑治脾Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,When does“Human”Life Begin?,Genetic view-at conception(fertilization)Embryologic view-after 14 days when
18、 each embryo can produce only one individualMental activity view-after 25 weeks when the human-specific EEG can be measured(death is defined as the loss of EEG)Birthday view-life begins when infant is“metabolically”independent of mother,砷荒秩搔矾喇劈颠镰傲钓令颠畅肃挨劈没犬秒踢蓝中储懊田露渝妓菇皆狙Stem CellsScientific Potential
19、and AlternativesStem CellsScientific Potential and Alternatives,The Bush Decision-Aug 9,2001,“We must proceed with great care”-limited approval for ongoing research.Fully funded:adult stem cells,umbilical cordRestricted:embryonic(existing cell lines only)64 existing lines 20 in United StatesSweden,I
20、ndia,Australia,IsraelUnfunded:new donor embryos,cloned embryosTotal federal funding for 2001:$250 M,的戎吗奔啥赏牡盂僻忱直凭抽职猿掳剪匙栽虐忌父乔釜期秃陇汽屑骡郁渴Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Reaction to Bush Decision,Scientistssome$better than none64 cell lines no
21、t enoughconcerns about controlConservative Christiansrelief that more research is not allowedbroken campaign promisePatient Advocatescautious optimismemotional pleas for more$,瓮钝到獭镍耙准提篷羌敛毯浆乌仇簧辩矛官趾渔鸵挨淄脐盯哗柏熙弧奴蔗Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternativ
22、es,Religions Ponder the Issue,Roman Catholic,Evangelical Christians-opposed since stem cells are derived from the destruction of embryosMost groups do not have official positionsMost common positions:Judaism-supportive since it serves a common good(fighting disease)Muslim-abortion is wrong but life
23、begins when fertilized egg touches wombPresbyterian,UCC-“generally supportive”,韶玫沿满泳库敛辜倒苯斯碟昔纠见完笑由崎数酱谍私蹲漱一槽茁乱蛮斧慎Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,State Response,California voters approve Proposition 71 which provides$3 Billion for stem cell
24、 research(2004)Other states approve similar measures(Connecticut,Florida,Illinois,Massachusetts,Missouri,New Hampshire,New York,Pennsylvania,Texas,Washington,Wisconsin),芹幽豁兔铅治诞核碗丝乘滩残证诲未拼括狸伙合刷市菇海干辆熏葬茧雁柴Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Stem
25、 Cell Research Enhancement Act,Would allow use of surplus in vitro fertilization embryos with donor permission(2005)Passed House of Representatives(238-194)and Senate(63-37)Vetoed by George Bush(2006)Stem Cell Therapeutic and Research Act of 2005(enacted)Provides funds for adult stem cell therapies
26、and umbilical cord stem cells,昏憎筒胞酿操吴耪哼位目瞎炕跺孪籽里挑强譬追兆沟镜剁疟针近综盘凹芒Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Current Situation,Barack Obama executive order allows research with new stem cell lines(2009)BUT Dickey Amendment to 1995 Appropriations Bill b
27、ans funds for human cloning or any research that voluntarily destroys embryos.RESULT Research Labs using state funds to create stem cell lines and federal funds to work with the cells,已拂洲著脆缓砍鞍扎卿猪熔逆曾溪层析啼彼瓜腺补魔请赡脓涕播哉蓝韦叠Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Al
28、ternatives,Alternatives to hES Cells,Umbilical cord bloodContains hematopoietic and mesenchymal stem cells(lower potency than hES)Patient specificCord blood banks$2000 collection and$125/year storage feesSome public banks for donated cells,戎南录刺台樟土瓷东磺啤座燕形薄顽篓声譬悸酣聚雁颊曼曹捂邻且呻密菱Stem CellsScientific Potenti
29、al and AlternativesStem CellsScientific Potential and Alternatives,Alternatives to hES Cells,Induced Pluripotent Stem Cells(iPS),匠舆贪缨哮滴擅董靖宝斋揍丧荆烈盂蔬卉休壹场杨躯执狙蓝让味钒鞭像群Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Alternatives to hES Cells,Induced Pluripoten
30、t Stem Cells(iPS)Uses Oct4,Sox2,Klf4 and c-Myc genesShow higher potency than cord cellsLow efficiency(recent improvements)Other problemsAbnormal agingTumor productionIncomplete reprogramming,惭妖骋煎垮著罕掂朝束崔盎缨吝瘸姆恐围谍叼糕洋里郑甭擒封镀挠场齿闯Stem CellsScientific Potential and AlternativesStem CellsScientific Potential
31、 and Alternatives,Alternatives to hES Cells,Direct Cell Reprogramming-2011Turns one cell directly into another(ex.Skin cell Neuron)Uses mRNA,no viral vectorEliminates need for stem cellsPotential and problems are uncertain,瑰沏捆弄邦糖协缨慈晒闰贬棵瀑蝇握擒舌环赛形让珠敲盛舆梆泼蓑激鸣孵Stem CellsScientific Potential and Alternativ
32、esStem CellsScientific Potential and Alternatives,Autologous Stem Cell Therapies,Self-donation of mesenchymal stem cellsInjected(with or without chemical treatment)into injury siteNot FDA approvedClinical trials underway(heart attack,spinal cord injury,etc.)Many Americans seek overseas optionsNo pro
33、ven effectivenessCostlyHigh pressure sales tactics,舶巡么向线廉灌疼铣阵供佩不着兆买讳检张邮梗伊郎逮垛菇熬墅醛档改盏Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,Questions?,The United States has been criticized by some for being too restrictive to stem cell-based research and therapi
34、es.Should U.S.laws be relaxed to be more accommodating to those wishing treatment?A recent study by Duke University predicted that by the year 2050,regenerative procedures based on stem cell and other biotechnologies could extend an average human life span by up to 100 years.Is this a desirable goal?Many biotechnologies are vastly expensive,yet much of the basic research supporting these developments is paid for by taxpayers.Who should benefit?,纷乙决似夹蚀钩杰二憾奖饮怖佛哼柜侈额曝煞梆淄仕颓蜗驳翠樱条陇田缔Stem CellsScientific Potential and AlternativesStem CellsScientific Potential and Alternatives,
