Classic Pages GEORGE E. PALADE Fine structure of blood capillaries Journal of Applied Physics, vol. 24, p. 1424, 1953 1424 PROCEEDINGS OF ELECTRON MICROSCOPE h ches t to a separate culd evacuati n chamber. T allows the preparation of many diffe ep a r a t i o n of manydiffe in a short period o[ time. Resultsar • u l t s a r i b l e tu those ob- 68. The Siibmicroscopic StructureolAni •;KITH R. I'.IHTHK, ol Animal Epidermis. Mtdical Ri mly i J Ilir i-piili-niiis nf The RttikrjdlrrInstUuIrfurMtdicalRi nstUuIr fur SOCIETY OF AMERICA regular layer of relatively dense material surrounds the out side surface of the endothelia. In favorable places, it appears as a felt of extraordinarily fine fibrils, -M OOA in diameter This layer corresponds- apparently to the basal membrane I lie host m lor C y p ing fluids across the capillary w y acc high permeability rate at the capillaries. For the interstitial lymph the system could work without any additional complication; for the blood plasma, however, a protein-retaining device has to be postulated at the level of the endothelial cells urther Studies an IhB Min my at numbers of f ,ihe<wriieal furfnec.I:e. The To in vcfiiKatc ihc effi!« ol fiwitioii nr>>n the resolution of line ions of the rat kidney hy the electron used, all buffered at pH 7.4 ells, (l i ) hy liifl 5 of fibntus ird tfic cell inlei md (e) UsO,. ilmi O-iO.onlv). F)i:tt renjilslswereobtained by rapid peri of the kidney of ancsthcl fued animals with Ringer's risk* - With ells i|rilhrii«s. Tin; ' "foot processes*" of the pcricyt -ral c pi tliL'l iiim ':if nawiiuiirs c^ijisLilel were must clcark' skeins {presuinnlily keratin) nre h. regions of ihe cell and lie rxir.ilkl f •brirlgK 1 ' arc• sni.il! m-inn* ,,f a, (if 1; of the cell in material direiScd'frnm then by the prt'stn The cpidenna branes, (I)) under this a layerof Li arranged in sever.il lay Of the Pulmonary Alveolar Wall in 09. Ulliflstn.! laboratory Mai mtftt of Atialomy, Louisiana Stole University School of Medicine, New Orleans, Louisiana.—The alveolar walls of the lung are covered by a surface layer of epithelium which encloses a rich capillary network and tissue spaces.' T fluid in which elastic fibers, un d cytoplasmic debris arc suspend osmium irregularly, are (enesira and are structurally amorphou ca. 300-350A thick, describe he and do not aggregate to form fibersvisiblei scope. A basement mcmbr.me • h than m m A thick, adhere* to capillary endothclium. The blooil-ai attenuated epithelium and endo m potential - tissue space between t d of these membranes. 70. Pine Structure of Blood Captlluies. GEORGE E. PALADE, TTb RtekefdUr Iniliiult for Medical teuonk. Sew York if, New York.—The structure of blood capillaries was studied in a number of organs such as skeletal muscles, heart, intestine, and pancreas. The endothelial cells form a continuous lining. Besides the usual cell components (nucleus, mitochondria, endoplutnk reticulum, small granular component), they possess two characteristic structural elements, namely: (a) intracellular fibrils of ~24OA diameter; (b) a large number of vesicles concentrated immediately under the cell membranes facing both the capillary lumen and the pericapillary spaces. The vesicles, w m c times tightly packed in la yers, are spherical in ahape and measure --650A in diameter. Many of these appear to open a t the surface of the cell membrane. A thin b> i,iin:il surface of tlic |ii >.\iinal con\"alutcil tubule organdies of the Hirsh th all fixatives, including Bakrr typc-r,.j|j;i l..,dy w Ohserrnlions on Ihe Fine Structure of Hepatic Cells. DON \V. FAIVCETT.1 77K Rocttjcllc Institute JOT Medical rch, jV«w York 21. A'(W York.—In an electron microscope - uf rat liver nciv .ibscrvaiioiis liavc liecn marie on the m of allachincnlufllic cells, the nature of their free surface, in ihe noriii.il slructuri: and mctbod of divi^iun of their m jchumlria. Cell surfnees •.-oiit^uuiis "-ith uthur liver cells have numerous Blud-likc processes which fit exactly into conies of appropriate shape in the surface ol the opposing These processes are often expanded at their tip while (he An s < locWng structure results which closely r rtise and tenon. Assuming that the ectoplasmof liver c ' is elled, this device would insure firm attachment of a d j a c i DE,lls. Cell surfaces which face sinusoids are covered n , d e l i filiform processes which are believed greatly to in:rease the surface area available for interchange of n i a t e i be I wren the hlfwx 1st ream nnd ihp interior of theccil. The milochondrti posses? two distinct membranes. The outer is a into nsirrow Mds and slender villi which project jn^'^r^ Under c " «! uhic c o n d i t i _,.r t«il by a thin transverse pan , comprised c two closely appr(j\inialet1 mcnibr.incs t i c margin v.ith the inner inilLK.-hondn.jl iiicin ;. The mtcrio jf the niitachondrion >, i i r luilvcs each limited by its own inciiibtJnc but bo th c o n t a i n c within a common outer mitochondria I mi This doubl This brief statement announced the discovery of capillary endothelial vesicles and contained Palade's hypothesis that these organelles may account for the high capillary permeability to fluids and solutes. This work immediately started a lively controversy about the molecular mechanisms of capillary permeability. Palade did not publish his full study until 1961. Downloaded from http://circres.ahajournals.org/ by guest on February 4, 2015 Classic Pages Circ Res. 1970;27:482 doi: 10.1161/01.RES.27.3.482 Circulation Research is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 1970 American Heart Association, Inc. All rights reserved. Print ISSN: 0009-7330. Online ISSN: 1524-4571 The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circres.ahajournals.org/content/27/3/482.citation Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation Research can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. 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