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1、對(duì)人體細(xì)胞和微生物數(shù)量的改進(jìn)估計(jì)RonSender1.OriginofprevalentclaimsintheliteratureonthenumberofbacterialcellsInhumans為什么大家會(huì)普遍認(rèn)為腸道微生物數(shù)量是人體細(xì)胞的十倍，本文作者對(duì)文獻(xiàn)進(jìn)行了追溯，結(jié)果顯示1977年Savage,annu,Rev.Microbiol引用超過(guò)一千。而它的計(jì)算基礎(chǔ)是胃腸道容積為1L，腸道微生物濃度為1011/g.2.Distributionofbacteriaindifferenthumano
2、rgans不同部位的微生物數(shù)量相差很大，由上表可知，人體微生物約90%都集中在結(jié)腸。所以作者統(tǒng)計(jì)了不同文獻(xiàn)的結(jié)腸微生物濃度，平均值為0.92*1011/g.3.Concentrationofbacteriainthecolon4.Thenumberofhumancellsina“standard”adultmaleAmass-basedorder-of-magnitudeestimateforthisnumberassumesa102kgman,whichisdividedbythemassofa“r
3、epresentative”mammalian,cell10-12-10-11kg(assumingcellvolumesof1,000-10,000μm3,spectively),thusarrivingat1013-1014cells.OnestudyusedaDNA-centeredmethod(Baserga,1985).Themethodbeginsbyestimatingthenumberofcellsinthebodyofa25gmousebydividingthetotalamount
4、ofDNA(statedtobe20mg)bytheDNAcontentofonediploidmousecell(6·10-12gDNApercell)toget≈3·109cellsina25gmouse.Thenextrapolatefrommousetohumanbyusingtheratioofmassestoget≈1013cellsinthehumanbody.ThismethodexcludescellsthatdonotcontainDNA,suchasredbloodcellsan
5、dplatelets.Summingoveratotalof56cellcategories(Bianconietal.,2013)resultedinanoverallestimateof3.7·1013humancellsinthebody(SD0.8·1013,i.e.CVof22%)5.UpdatedinventoryofhumancellsinthebodyWefocusonthesixcelltypesthatwererecentlyidentified(Bianconietal.,201
6、3)tocomprise97%ofthehumancellcount:redbloodcellaccountingfor70%),glialcells(8%),endothelialcells(7%),dermafibroblasts(5%),platelets(4%)andbonemarrowcells(2%).Theother50celltypesaccountfortheremaining3%.5.UpdatedinventoryofhumancellsinthebodyRedbloodcell
7、s:(Boer,1984;FeldschuhandEnson,1977;Nadleretal.,1962;Snyderetal.,1975)4.9L(Ambayyaetal.,2014;Dosooetal.,2012;Nordinetal.,2004;Pekelharingetal.,2010;VolkmerandHeinemann,2011;Wakemanetal.,2007)5.0·1012cells/L(SEM1.2%,CV7%)(SEM1.6%,CV9%)Thisledtoatotalof2.
8、5·1013redbloodcells(SEM2%,CV12%)Thisissimilartotheearlierreportof2.6·1013cells(Bianconietal.,2013).5.Updatedinventoryofhumancellsinthebodyglialcells:Thenumberofglialcellswaspreviouslyreportedas3·1012(Bianconietal.,2013)estimateis
