Corneocytes Undergo Systematic Changes in
Element Concentrations Across the Human Inner
Stratum Corneum
Ronald R. Warner, Rodney D. Bush, and Nick A. Ruebusch
Miami Valley Laboratories, Procter & Ga mbl e Co., P.O. Box 538707, Cincinnati, Ohio, U .S.A.
Using analytical electron microscopy of freeze-dried
cryosections, physiologic elements were visualized
within individual cells across the human inner stratum corneum. Human corneocytes undergo systematic changes in element composition as they advance
through this region. Phosphorus is largely excluded
from the stratum corneum, undergoing a precipitous
drop in concentration at the granular/stratum corneum interface. The cellular potassium concentration has a profile similar to that of phosphorus but
with a slower decline, thus migrating further into the
stratum corneum. In contrast, the cellular chloride
concentration increases in the innermost corneocyte
layer, increases further in the subsequent layer or two
(as potassium declines), and then decreases to values
comparable to those in the innermost corneocyte.
The cellular sodium concentration (per unit volume
of tissue) is relatively unaltered in transit across the
inner stratum corneum. The initial potassium and
chloride movements are oppositely directed and have
the appearance of creating an electrical charge
imbalance. The position-dependent alterations in
corneocyte elemental composition may reflect sequential stages of chemical maturation occurring
intracellularly during stratum corneum transit, an
example of which is the breakdown of filaggrin that
occurs over this same region of the inner stratum
corneum. ] Invest Dermatol 104:530-536, 1995
T
Hkely reflect innate biochemical alterations occurring intrace llularl y
as cells transform from a viable granular layer in to "mature"
corneocytes within the uniqu e SC environment. We suggest that
the breakdown of ftlaggrin co uld account for some of the observed
corneocyte elemental distributions.
he stratuin corneum (SC) has often been considered
homogeneous in its structure and its barrier properties [1,2], but this co ncept is increasingly difficult to
reconcile with mounting evidence for chemical and
physical heterogeneity across tlus region of skin.
Biochemical differences between the inner and outer SC are known
to exist for proteins [3-7], lipids [8-10], and low-molecular-weight
compo unds [5,11], suggesting that a che mi cal maturation occurs
across the SC. Similarly, and perhaps as a res ult of the chemica l
changes , there are known differences in morphology [12-15],
water-holding capacity [11] , and stru ctural integrity (cohesiveness)
[12,16-18] between the inn er and outer Sc.
Using ana lytica l electron microscopy, this laboratory previously
presented inorganic elem ent profiles across skin that showed steep
gradients for Na, K, and Cl across the outer SC [19]. In addition,
these element profiles indicated that a variety of changes in element
composition occ ur over the gra nulosum /SC junction. In this paper
we investigate the e lement distribution over the inner SC in more
detail. We show that a syste matic progression in element composition occurs over the first few corneocyte layers witll.in the inner
SC. These changes in ele m ent co mposition within the inner SC
MATEIUALS AND METHODS
Sample Preparation Sample preparation has been described previously
[20). BrieAy, human skin biopsies were taken fro m the lower leg of five
individual s with normal-appea ring skin. No Auid of any kind was appli ed to
the ski n prior to biopsy. The biopsy was obtained from a whea l raised by the
subcutaneous inj ection of lidocai ne (xyloca in e , 2%) with epillcphrinc
(1:100,000) . Witlun approximatcly 1 min, a portion of thc biopsy was
plunge-frozen in a stirred, liquid-nitrogen-cooled 90'% propane-lO% isopentane mix ture . One-micron-tluck cryosections were cut with a R e ichert
FC4E cryo ultramicrotome (C ambridge Instruments , Deerfield, IL) at
- 110°C, sandwiched between aluminum-coatcd Formvar films on a n ickel
slot grid (Tcd Pe ll a, In c., Redding, CAl, and £i'ecze-dried overnight in a
Denton DV-502 vacuum evaporator (Chcrry Hill, NJ) at 1.3 X 10- 4 Pa.
One-micron cryosection s wcre uscd because they provide adeq uate spatial
rcsoluti on for ceUul ar studies but avoid pro blem s of mass loss that occur in
tlunner sections ana lyzed at higher resolu tion [21,22]' Sections w ere
removed from the vacuum evaporator and analyzed imm ediately that day.
Tlus sample preparation procedure has been shown to preserve inorgalu c
clemcnt distributions at thc sa me or lugher reso lution than that used in tlus
study [23-26] .
Manuscript received July 14, 1994; revised December 2, 1994; accepted
for publication December 13,1994.
Tlus work was published in abstract form U fllll est Dcnll otoI 94:589, 1990).
Nick A. R.uebusch's current address: Sharon Woods Technical Center,
11511 Reed Hartman Highway , Procter & Ga mble Co ., C in cll1l1ati , OH
45239.
Reprint requests to: R .R. Wamer, Miami Valley Laboratories, Procter &
Gamble Co., P.O. Box 538707, C in cinnati, OH 45253 .
Abbreviation s: SC, stratum co rn eum; STEM, scanning transm ission
c1ectron microscopy.
Analytical Electron Microscopy Electron images, x-ray maps , linc
scans , and illtra ceUular point mi croa nalyscs wcrc obtallled usi.ng a Hitaclu
H-500 analytical e lectron microscope (Hitaclu In strumcnts, Mountain
View, CAl operated in the sC'lI1ning transmission electron microscope
(STEM) mod e at 100 kV with a sa mple current of 0 .5 nA. X-ray spcctra
were coll ected on a Tracor Northern 5500 cncrgy dispersive spectrometcr
systcm with a beryllium window (Noran, Middleton, WI). Elemcnts of
atomic number 11 (sodium) and above can be detected with this system.
0022-202X/95/S09.S0 • SSDI0022-202X(94)00377-j • Co pyright © 1995 by T h e Society for In vestigativc Dermato logy, In c.
530
VOL. 104 . NO. 4
SYSTEMATIC ELEMENT C HANGES IN INNER SC
APIUL 1995
Typically, x-ray maps were acquired for 8 h overnight, and linescans were
acquired for 4 h. Quantitative clem ent con centration s were d etermined
using the Hall quantitative technique [27) using a concinuwll (x-ray
background) region b etween 4.5 and 6 .0 kev . X-ray cononuum counts arc
proportio nal to dry mass and were also m eas ured between 4.5 and 6.0 kev.
Ma ss and e lement loss were monitored during analysis [21 ) and were always
less than 10%. Concentrations were ca lculated with the Tracor Northern
BIOQ software and are reported as mmollkg dry weight.
Statistical Analysis Values are reported as means with their standard
errors. Differences between m eans were eva luated using the two-tailed
Student t tcst; values are considered significant for p < 0.05 .
RESULTS
Spectra (Raw Data) Reveal Large Changes in Elemental
Composition Between Inner SC Cell Layers R e presentative
x-ray spectra from the innermost SC cell layer and from the second
SC cell layer of a single individual are shown in Fig 1. Peaks from
the physiologic elements sodium.' phosphor~s, sulfur, c hlorine: and
potassium are evident (the alumillum and nickel peaks are artlfacts
from the supporting grid and fum). The sulfur p ea k likely originates
predominantly from keratin. A phosphorus pea k is prominent in the
umermost SC cell but is barely above background by the second SC
layer. The potassium p ea k has also decreased with comeocyte
transit, but there is an increase in the chlorine pea k.
X-Ray Maps Reveal Systematic Changes in Elel1'lent Composition Across the SC A STEM image of the SC and .th e
corresponding x-ray elemental maps for phosphorus, chlOrIde,
potassium, sodium, and. sulfur are shown U1 Fig 2 . .The STEM
image shows the full tluckness of the SC; .an U\:derlY1l1g. granular
cell layer is present (lower left comer), Identlfied by Its much
lighte r appearance. From th e corresp.onding x-ray maps,. the elem ental gradients in the outer SC are VIsuall y not as drall1atlC as that
shown in our previous study [19]. Similar but somewhat smaller
gradients are nonetheless present; the "noisy" x-ray m <i ps are not as
O~~llillillilliillillllillilliillillilllliillillmlliillmm~~
o
Kev
-----.-- I-
10.2
j-f-.---t-----.- --t----+----- ---
-._--- -- ._--
...
p
f----f---.---.-I---+--..--,--...-.- f----..
~f
T11mIrfnli II f
. 1 ~~~,-1----~-~-/I ~-f----f----
Kev
I rn~
10.2
Figure 1. Examples of x-ray spectra from the first two inner SC cell
layers. X-ray spectra ITom the inn crm ost SC cell layer (upper spectrum)
and fi'om the second inn c r SC cell layer (lower speco'um) from a single
individual. The ni ckel and aluminum peaks in these spectl'a arc artif.1cts
from the suppo rt grid and fi lm .
531
sensitive an indicator of a gradient as are the integrated point counts
of the previous u1Vestigation .
Prior to the conti.tlUously incL'easulg element gradients for sodium, potassium, and chlorine in the outer SC [19], a variety of
dispa rate elemental distributions are observed in the inner SC (Fig
2). By comparing the x-ray m ap for phosphorus Ul Fig 2 with the
corresponding STEM unage, phosphorus is seen to be largely
limited to th e granular cell layer but with som e phosphorus visible
in the um ermost SC cell layer. T he potassium profile is si.tnilar to
that of phosphorus but penetrates further UltO the SC. Chloride, in
contrast, increases in concentration in a step- wise manner before
decli.tw1g to values near th e initial SC level. Sodium correlates w ith
neither the potassium nor chlodde distributions al1d is generally
w1altered or only slowly increases (per unit volume) Ul transit
across the imler SC. The cellular sulfur concentration monotonically increases across the SC presumably due to the concentrating
effects of cellular desiccation during transit [19].
The elemental variations in the ilmer SC from the same individual but from a different region at high er magnification are shown Ul
Fig 3. A portion of a granular cell is visible at the bottom of the
STEM image in Fig 3, and at this m agnifica tion approximately five
corneocyte layers are in tlle field of view. As shown Ul the adjacent
x-ray map, phosphorus is present at reduced levels within the
ilmermost SC cell layer al1d is virtually excluded from subsequent
layers. The first SC cell layer (or trallsitional cell layer) con tains
what is presumably a degenerati.t1g nucleus, identified by the very
bright phosphorus signal Ul the lower right portion of the phosphorus m ap. The potassium una ge shows a perceptible drop in concentration in the first SC cell layer, but then a more apparent
decrease in the subsequen ' cell layer and the virtual disappearance
of potassium in the third cell layer. Chloride, ill contrast, sh ows an
increase in concentration at the first SC ceIJ layer, a sunilar level in
the second SC layer, a jump in conce ntration in th e tllird cell layer
(when potassium is near ze ro), and then a drop U1 CI to the earlier
SC chlodd e levels . The more m onotonically in creasing gradients
for sodium and sulfur are also apparent.
Other allalyzed regions from tlus same individual display a
slightly different elem ental distribution in that tile profiles described
abo ve are more cond ensed (data not shown). Phosphorus is confined to the viable tissue an d does not appreciably enter the SC.
T he potassium decline occurs over the innermost t"vo SC ceU
layers, as do the two sequential increases i.n chloride concentration _
T he som ewhat variable onset and duration of the inner SC element
profiles likely represent a naturally occurrin g regional vadation or
perhaps difFe rent times of entry into the SC .
Linescans Reveal Iuner SC Profiles for P, K, and CI Thc
phosphorus, potassium, and chlorid e profiles across the inne r SC
are shown graplucally in the linescans of Fig 4. T hese profiles arc
fi'om a different individual than that shown U1 Figs 2 and 3. The
profiles a.re typical of the rem ainin g biopsies and are similar to thc
previous x-ray m aps. Black lines on the STEM unages in Fig 4
show tile patll taken by the electron beam. T he adjacent line
profiles displ ayed on the right have x-ray co unts (per unit volumc)
on the y-axis and distance traversed o n the x- axis . The upper
IU1escan across the full thicklless of the SC shows very high C I and
K va lues at the skin surface and outermost SC. By comparison ,
elem ent changes i.n the inner SC are mllch smaller. As shown at the
SC/granulosum interface in th e upper linescan, and at this same
interfa ce in a different region at lugber magnification in thc lower
linescan , intracellular phosphorus decreases abruptly and nearly
co mpl etely over the first SC ceIJ layer to a low and constant valu e
across the remall1der of the SC. Potassium decreases more slowl y
and continu es further into the SC before declulu1g to very low
levels_ The onset of the decrease in potassium generally correlates
with the onset of an increase in dUOI·ide. The chloride concentratio n peaks, then subsequently decl-cases in the mid SC but remains
at a substanti al level. N ote that the decrease in potassium and
increase in chloride that occurs w ithin the inner SC wo uld appear
to defY charge balance.
532
WARNER ET AL
THE JOURNAL OF I NVESTIGATIVE DERMATOLOGY
Figure 2. Element distributions across the full thickness of the s tratum corneum. Upper left im age is a STEM micrograph showing a portion of
a granular cell in the lower left corn er and th e outermost SC corn eocyte ill th e upper right of the image. Separati ons betwee n SC corneocytes are like ly
artifacts of cryosectioning. Graysca le for the correspond in g x-ray m aps for C I, P , K, Na, and S: IJlnck denotes the absence of the elem cnt, ",hile th e highest
value for the elements. GrayscaIc units are related to x-ray counts per uni t vo lum c of tissue .
VOL. 104. NO.4
APRIL 1995
SYSTEMATIC ELEMENT C HANGES IN INNER SC
533
Fig~rc 3. Elcmcntal distributions across thc inncr SC. Upper left image is a STEM micrograph showin g a portion of a gran ular cell at the bottom of
the Illlage. A vertica l teal' in the Cl'yosection nea rl y bisects the gr31llllar layer. Imm cdiately above the granular cell is a tr;U1sitional layer showing a degenerating
nucl eus. The overlying four to fivc cell layers arc corneocytes. A n additional five or more la yers of corneoctyes arc present but not shown at tlus
maglufi ca tion. Corresponding x-ray Illaps an: shown for I, P, K, Na , and S.
534
WARNER ET AL
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
Figure 4. Line scans depict Cl, K, and P profiles across the SC. Upper /ill e scali: el ement profiles across the entirc SC. In the STEM mjcrograph , via ble
tissue is at thc top (a nucleu s is visible in the upp er right corncr) and th e outcrmost SC cclls at the bottom. The conGlmination track of the electron beam
is visiblc in the mjcrograph, slightly displ aced from the computer-drawn overlay (squjggly white line) . The white .. +" on the computer-drawn line
correspo nds iJl position to the vertical cursor superimposed on th e adjacent lin e scan profiles. In th e adjacent ljne scan, the distance traversed by th e e lectron
beam is represented by the x-axis and the x-ray intcn sities (element concentrations) displayed on thc y-axis. Y-axis sca le , 0-7000 co unts. LOl/ler /iIl C sen ll :
c1cmcnt profi lcs across thc inn e r SC. Thc granular layer is in th e upper lcft corner. T hjs layer and fOll[ SC cell laycrs are traversed by th e path of th c scan n cd
beam, denoted by the computcr-drawn sq uiggly bla ck linc. T h e white "+" on tlus computer line dcnotes the begiJlJung of tbe second SC ccU layer and
corrcsponds to the white arrows on thc adjacent \.inc profiJcs. Y-axis scale, 0-700 co unts .
Quantitative Point Counts Indicate Net Addition of CI to
Cell Interior Not only does chloride incre ase per unit volume
w ithin the inner SC, as shown visually in the above figure s, but it
appears to increase per unit dey weight within the SC as shown by
the intracellular point ana lyses in Table I . As indica te d by the
contin uum co unts (proportional to dey mass) in this tab le, dry mass
(per unit volume of analysis) constantly increases over the inner SC
due to com eocyte desicca tion. Consequently, thc in crease in
intracellular chloride observed in the second SC cell layer in Table
I is not du e to a drop in dey weight but appears to be due to a net
addition of chloride to the cell interior.
DISCUSSION
We believe th e position-dependent alteratio ns in corneocyte elemental composition described above reflect a cell maturation that
occurs during transit across the iJ1I1er SC. Of particular interest is
VOL. 104. NO. 4
Table I.
SYSTEMATIC ELEMENT CHANGES IN INNER SC
APRJL 1995
Intracellular Element Concentrations (mmol/kg dry wt) and Continuum" Measurements (Counts/lOO Seconds)
Vary Across the Inner Stratum Corneum (Mean ± SEM. n
Sir
=
Na
GRl
SCl
SC2
SC3
535
110
90
41
57
:!:
:!:
:!:
:!:
18
23
16
13
108
105
117
148
:!:
:!:
:!:
:!:
8
12
16
12
263
104
21
6
:!:
:!:
:!:
:!:
Cl
K
P
S
28
20
6
2
290
130
62
30
:!:
:!:
:!:
:!:
147
145
178
126
37
22
16
8
:!:
:!:
:!:
:!:
Continuum
15
18
13"
12
566
969
1092
1270
:!:
:!:
:!:
:!:
63
155
152
107
Continuum is the x-ray backgro und i11 a spectrum and is directly rclMcd to the section dry mass .
/. Five individu:lls. Olle cryoscction each individual. one measurement each region per cryoscctioll.
r GR, o uter granuJoslIlll ce ll;
C, stratum corneum cell.
II
,/ Statistically elevated over SCt and SC3 values.
the remarkable increase in chloride coupled with an exit of
potassium that occurs within an inner SC corneocyte, as visualized
in Figs 2-4. The opposing chloride and potassium ion movements
appear to create a c har?e imbalance, becaus~ sodium is approximately constant (per umt volume) across the 1I1ner SC and there IS
little intracellular phosphate available to exchange with chloride at
that position within the SC. The authors are llI1aware of similar
changes in physiologic elements in any other organ system. Because
we know from the x- ray spectra that no othel' inorganic elements
are present in the SC that could account for the apparent charge
imbalance, the perceived imbalance must be due to biochemical
changes resulting in the generation or movement of charged
organic molecules or hydroge.n ions..
.
.
One explanation for potassium eXit and ch londe entry mto the
corneocyte would be the biochemical conversion of neutral or
negatively c harged ma cromolecul es .into predom in;u~tl~ positively
charged macromo lecules (fixed POSitive c harges) wlthm the corneocyte cytoplasm. This biochemical transform ation would likely
occur by liberation of carbo;\.'ylate groups, leaving behind the amine
functionalities. The very applicable Donnan equilibrium equations
[28] would predict anion/cation shifts du e to this biochemical
conversion that wou ld be very similar to the ch.loride/potassium
sh.ifts that we observe.
A lternatively, one of the more significant biochemical changes in
corneocyte composition is the degradation of fi laggrin in the ea rly
SC [5,29]. FiJaggl;n proteolysis begins apparently simult;uleously
with entry into the SC [30], and as shown by immunocytoche mistry, substantial d egradation is completed by the second and t1ul·d SC
celJ layers [4]. The fllaggrin distribution would thus appear to
correlate well with our observed potassium distribution (and inversely with the chloride distribution). Although obviously speClIlative, we suggest that the filaggrin and ion distributions co uld be
related, as ind icated schematical ly in Fig 5 . As shown in t1us figure,
the conversion of filaggrin into (primarily) acidic amino acids and
acidic "natura l moisturizing factors" [5,30] would occur not by
liberation of carboxylate groups but by the loss of the amine
functionalities. A lthough this would not generate macromolec ules
with a fixed positive charge, it could lea d to a net increase in
intracellular acid ity that wou ld he lp drive potassium from-and
chloride into-the cell as we observe. We wou ld furth e r speculate
that generated intracell u lar acidity could playa role in the SC, for
instan ce, by contributing to the "acid mantle" [31] .
It would hav e been prefe rable in this study to obtain biopsies
without use of a local anesthetic, because it is possible for the
anesthetic to affect ion gradients. Unfortunate ly, our source of
biopsies was from a larger clinical study that dictated anesthetic use .
However, w e beli eve that the anesthetic did not alter the SC ion
gradients for the following reasons .
The anestheti c is release d subcutaneous]y at least a hundred
mi c rons away from the stratum corneum, and diffus ion is a
relatively slow process over such dimensions.
Va lues for diffusib le ulorgani c clement concentrations in the
granu lar layer (Table I) are comparable to those measured
previously in human skin obtained with 10c;11 an esthesia [32,33]
and Ul guinea pig skin obtained without the use of anesthetics
[34,35].
Figures 2-4 show preservation of sharp cell-to-cell element
concentration gradients, suggesting free difFusion has not occlllTed.
A recent x-ray analysis study of human skin by Zglinicki el al found
no gradients for the monovalent ions sodium, potassilll11, or
c hlorid e witlUll the stratwn co rneum [33], Ul conflict Witll both our
current and previous [19] results. Although the study by Zg1inicki
el al appears to have b ee n done well, th e resolution of tlleir bulk
sample analysis is much worse tllan ours, and the stratum corneWll
was measured as a single value. Working at mu ch Iu g h er resolution
we routinely observe element gradients in the stratum conl e U111, as
illustrated Ul Figs 2-4, and attribute the discrepancy b etween our
laboratories as sUllply due to differen ces in resolution between the
two tec hniques.
W e have shown that the inner SC is not homogeneo us in
inorgmuc eleme ntal composition . Furthermore, the elemental inhomoge neity follows a fixed pattern in which compositional
c hanges occur within the SC in a systematic fashion. Inorganic
elements thus join the list of known chemical h eterogeneities
[3-11] that exist across the Sc. Our study adds additional data that
shou ld facilitate a more co mprehensiv e wlderstanding of terminal
differe ntiation.
m.AGGRIN
OOMPONENTS
IONIC CON]ENT
~~.rL.ml ·
GRANUlAR
Set
pKa •
sa
•
pKa I
....-..
"""""""-
""'*""
AMINO ACIDS.
P'lROUlDONE CARBOXYUC ACID.
UROCANIC ACID. ORNITHINE.
H; NH. t
Figure 5. Speculation on how intra-conleocyte electrolyte changes
could be related to filaggrin degradation. Schematic illustration of the
breakdown of profibggrin into filaggrin, amino acids. and final degradation
produ cts (natllralmoistllrizing factors) across the inn er SC. Also shown arc
pKa chan ges associated with amino acid co nvers ion into final degradation
products. Notc the stepwise formation of increasing acidity wi.th progression
into the inner SC. with a correspo ndin g impact o n the intracellular content
of potassium and chloride.
536
THE JOURNAL OF INVESTIGATIVE DERMATOLOGY
WARNER r:.T AL
REFElliN CES
1.
2.
3.
IGigman AM: T h e biology of the stratum corneum . In: Montagna W, Lobitz WC
(eds.). T /, e Epiderlllis. New York, Academic Press, 1964, PI' 387-433
Idso l1 B: Percutan eous absorption.) P/II/rlll Sci 64:901-924, '1975
Warho l MJ, Roth J, Lucocq JM , Pinkus GS, l'lice R.H: Immul10ultrastructllral
.1 8.
Chapll1:ln 5J. Walsh A , Ja ckson SM. Friedmann PS: Lipids. proteins alld
19.
corneocyte adhesion. A rch oCl"llIalol Res 283 :167- 173, 199'1
Warner RR, MyerS MC, Taylor DA: Electron probe analysis of humall skill :
elemcnt conce ll tratio n profi lcs. ) I,, "csl DI:,.,I/alo{ 90:78-85. '19 88
20.
Warner RJt. Myers MC, Taylor DA: Electron probe analysis of humall skill :
detcrm.inatio n of the water concentratio n profi le. } IlI lIcSI Dal1latol 90:21 8-224.
'1988
2 1.
Myers MC. Warner IUt: A routine procedure for monitoring: samp le mass during
locali zation of invo lucrin in squamolls epithelium and cultured kc ratinocytes.
4.
5.
6.
7.
) HislocllclII Cylocllelll 33:141-149, '1985
Steven AC, Bisher ME, Rool' DR, Ste in ert PM: Biosynthctic pathways of
fi laggrin and ioricrin-two major proteins expressed by tcrminOl Uy differentiated epide""al kcratinocytcs. ) Strllet Bio/l04:150 - 162, 1990
Scott IR, Harding CR, Barrett JB: Histidine-rich protein of the keratohyalin
granules: source of the frcc am in o acids, ufocan.i c acid and pyrro lidollc
carboxylic acid in mammalian stratum corneum. Biochi/ll Biopltys Acla 7 1. 9: 110117, 1982
Giinzc l S, Wcidcntha.lcr D, Hausser I, Anton-Lamprecht I: Keratohyalin granules
arc heterogeneous in ridged and no n-ridged human skin : evidence [r'om
an ti-filaggrin imll1unogold labellin g of normal skin ;lI1d sk.in of .au tosomal
dominant ichth yosis vu lg aris patients. Arch Dl:rl1laloJ Res 283:42 1-432. '1991
microa nal ysis. In: Armstrong JT (cd.). Microbealll Analysis-1985. Sail Francisco Press , San Francisco, 1985. PI' 129-"13 1
22.
8.
to cross-linked envelope.) hlVesl Derlll alo/ 97: "1 06 1- 1072. 1991
Lampe MA , Williams ML, Elias PM : Human epiderma l lipids: characterization
and modulations during differentiation.) Lipid Res 24:13 1- 140, 1983
9.
Long SA, We rtz PW, Stra uss JS. Downing DT: L-Ium;m stratum corn eum polar
10.
E1.i ns PM, Mcnon GK, Grayson S, Drown BE: Mcmbrnnc structural alterations in
mll.rine stratum corn cum: relationsh.ip to the localiz.ation of polar lipids and
11 .
Hashimoto-K umasaka K, J-Jori.i I. T :lgam i I-I: In v itro comparison of waterho ldin g capacity of the supcrficial and deeper layers of the stra tum corn Cum .
23 .
Soml yo AV. Shuman H , Soml yo AP: Ele menta l distributi o n in striated muscle
and cflects of h ypertonicity; electron probe analysis of cryosections. ) Cdl Bio/
24.
Lcchene C P, W:lrner IUt: U ltrami croa ll alys is: x-ray spectrometry by e lectron
25.
GUpt;1 BL.
26.
Academic Press, New York, "1977, PI' 83-143
Dorge A. R.ick 11..• Ge hrin g K, T ilurau K: Preparation of freeze-dried cryoseetio ns
74:828-857, 1977
probe exci\ation . AIIIIII ReI' Bi0l'/')'s Bioellg 6:57-85, 1977
12.
Arc" Dermalll/ Res 283 :342-346 , 199'1
King CS, Barton SP, Nicho lls S, Marks 11..: T he change in properties o f the
13.
Mjchc l S, Schmid t R, Shroot 13 , Reichert U: Morp ho logica l and bioche mical
stratum corneulll ~IS a function of depth. Br) Dcrtllffloi 100:1 65-172 ! 1979
characterizatio n of the cornified envclo pes from human epidermal kerati no-
cytes of diffe rent origin.) illllesl Dermalol 91 :11 - 15, 1988
14.
Chapman SJ. Walsh A: Desmosol11 cs. com cosomcs. and desquamation: an ultrastructural study of adult pig epidem,is. f iori, oenll nlo/ Res 282:304-310. 1990
15.
Men on GK, Feingo ld KR. Mao-Qiang M. Schaude M, Elias PM : Structura l basis
for the barrier abnormauty followi ng inh.ibitio n of HM G CoA reductasc in
16.
17.
murine epidermis.) IlI lIest DerlllaIIl1 98:209-219, 1992
Gray GM. W hi te 1\) . Williams R .I-I. Yardley 1-1]: Lipid composition of the superficial
stratum corne um cells of pig epidernlis. Br) De/1/IIIIOll 06:59-63, 1982
Bowser PA, White RJ : Isolation. b<Jrricr propcrties and li pid anal ysis of stratum
cO l11pactum .:t discrete region o f thc str:ltul11 corncum. Dr) lJeflllflfo/112:1-14,
1985
Hall TA. M o reton 1U3: Electro n probe X- ra y microa nal ys is . In : Gupta
fiL. Moreton RD. Oschman JL, Wall BJ. Tra"sport of 10/l s ami I'Vater ill A"lwals.
for quantitative X -ra y mi c roan~llysi s of elcctrolytes in biologiGl1 soft tissllcs .
J>jIlIgers A rcil 373:85-97, 1978
27.
Hal.l TA: The m.icropro bc assay of chemical clements. (n: Oster G (cd.). PII}'sicn {
T eclll1;qll cs ill Biological Research, 211(1 ed. , Vo i lA. ACildcmic Press , New Yo rk.
28.
29.
Donnan FG: T he theory or mcmbran e cqu.i.l.ibria . ChcIII RClf l :73-90. '192 4
lipids and desq uama tion. Arcll Dermalol Res 277:284 -287, 1985
phospholipase,.) l"I'est DenIlOI<l191:3-10, 1988
J
Micm;c 141 :319-328. 1986
Serre G, Mils V. Haftek M , Vin cent C, Croute F, R.i:ano A, O "hayoun J-p,
.Bcttingen S, Solci.lh avo llp J-P: Identifica tion of late di.ffercnti:ltion antigens of
hurnan con1.ified epithelia, expressed in re-organized desmosomes and bound
Hall TA: Pro perties of frozen sections relevant to qU:lI1titative microa nalys is.
1971, PI' 157-275
Scott IR., Hardin g CR.: Studies o n the synth esis and degradation of a high
mo lccular weight hi stidine-ri ch phosp hoprotei n from mamllJalian epidermis.
Bioc/lill' Billl'lI)'s ;jet" 669:65-78, 1981
30.
Harding Crt, Scott
m.: Histidine-rich
proteins (filaggrins): structural and fun c-
tio nal heterogene ity during ep ide rm al differentiation.) AI/oj Bioi 170:651-673.
31.
32.
33 .
1983
Schade H, Marchio nini A: Der Sii uremantel der rlaltt. K/ill Wellllsellr 7:/ 2- 14.
1928
.
Grundin TG, Roomans GM, Forslind B, Lindberg M , Werner Y: X-ray
microanalysis of psoriatic skin .) Ill vesl Derlllalo/ 85:378-380, 1985
VO Il
Zgtiniclci T. Lindberg M, Roomans GM . Forslind B: Water and ion
distribution profiles in human skin. Acta DeY/II Vellereo/ 73:340-343, 1993
34 .
Forslind B. Wei X, R oomans G M: Elcmcnw l distributio ll jn cross scctio ns of
g uincil- pig epide rmis: x-ray rnicroanalysis in the electro n 1l1icroscope. In :
Marks It, Plewig G (cds.). Slmllllll C" I1I elllll . Sprin ger-Verlag, Heidelberg.
J 983. PI' 217-220
35.
Lindberg M . Fors lin d B, S:lgstro rn S. Rooll1ans GM : ElclIlCnwJ changes in g ui.n e:1
pig epidern1.is at repeated exposure to sodium laury l sulf.,lte . Act(/ Ocn" Jlell cm{
72:428-43 1. 1992