X-Ray Emission Microanalysis of Proteins and Sulphur in Rat Plantar Epidermis

1968 ◽  
Vol 3 (4) ◽  
pp. 563-572
Author(s):  
R. T. SIMS ◽  
T. HALL
Keyword(s):  
Stratum Corneum ◽  
Unit Area ◽  
Skin Surface ◽  
Albino Rats ◽  
Paraffin Sections ◽  
Volume Changes ◽  
Mass Unit ◽  
X Ray ◽  
Stratum Spinosum ◽  
Cell Volumes

The distributions of proteins and protein-bound sulphur have been studied by X-ray emission microanalysis in the plantar epidermis of six albino rats. Plantar skin was fixed in 10% formaldehyde for 24 h and 5-µ paraffin sections obtained. Discrete and continuous measurements of the relative concentrations (mass/unit area) of proteins and sulphur were made along lines of scan perpendicular to the skin surface. The concentrations of proteins and sulphur almost double from the stratum basale across the stratum spinosum. There is a sharp twofold increase in their concentrations across the stratum granulosum to the stratum corneum where they become constant. The sulphur:protein ratio is constant across all layers of the epidermis. Rough estimates of cell volumes give a ratio of 1:9:7.5 for the cells of the strata basale, granulosum and corneum respectively. Cell volume changes cannot be responsible for the changes in concentration so it is concluded that epidermal cells synthesize and accumulate proteins throughout their migration to the stratum corneum. The observations are regarded as circumstantial evidence for the incorporation of keratohyalin granules into cornified cells.

scholarly journals Pressure- and Temperature-Induced Insertion of N2, O2 and CH4 to Ag-Natrolite

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4096
Author(s):  
Donghoon Seoung ◽  
Hyeonsu Kim ◽  
Pyosang Kim ◽  
Yongmoon Lee
Keyword(s):  
Unit Cell Volume ◽  
Molecular Size ◽  
Unit Cell ◽  
Volume Changes ◽  
Volume Increase ◽  
X Ray ◽  
Onset Pressure ◽  
Two Stages ◽  
Cell Volumes

This paper aimed to investigate the structural and chemical changes of Ag-natrolite (Ag16Al16Si24O80·16H2O, Ag-NAT) in the presence of different pressure transmitting mediums (PTMs), such as N2, O2 and CH4, up to ~8 GPa and 250 °C using in situ synchrotron X-ray powder diffraction and Rietveld refinement. Pressure-induced insertion occurs in two stages in the case of N2 and O2 runs, as opposed to the CH4 run. First changes of the unit cell volume in N2, O2 and CH4 runs are observed at 0.88(5) GPa, 1.05(5) GPa and 1.84(5) GPa with increase of 5.7(1)%, 5.5(1)% and 5.7(1)%, respectively. Subsequent volume changes of Ag-natrolite in the presence of N2 and O2 appear at 2.15(5) GPa and 5.24(5) GPa with a volume increase of 0.8(1)% and a decrease of 3.0(1)%, respectively. The bulk moduli of the Ag-NAT change from 42(1) to 49(7), from 38(1) to 227(1) and from 49(3) to 79(2) in the case of N2, O2 and CH4 runs, respectively, revealing that the Ag-NAT becomes more incompressible after each insertion of PTM molecules. The shape of the channel window of the Ag-NAT changes from elliptical to more circular after the uptake of N2, O2 and CH4. Overall, the experimental results of Ag-NAT from our previous data and this work establish that the onset pressure exponentially increases with the molecular size. The unit cell volumes of the expanded (or contracted) phases of the Ag-NAT have a linear relationship and limit to maximally expand and contract upon pressure-induced insertion.

scholarly journals Lipid Metabolic Events Underlying the Formation of the Corneocyte Lipid Envelope

2021 ◽  
pp. 1-13
Author(s):  
Philip W. Wertz
Keyword(s):  
Stratum Corneum ◽  
Outer Surface ◽  
Barrier Function ◽  
Skin Surface ◽  
Schiff’S Base ◽  
Cornified Envelope ◽  
Epoxy Alcohol ◽  
Viable Epidermis ◽  
Transglutaminase 1 ◽  
Base Formation

Cornified cells of the stratum corneum have a monolayer of an unusual lipid covalently attached to the outer surface. This is referred to as the corneocyte lipid envelope (CLE). It consists of a monolayer of ω-hydroxyceramides covalently attached to the outer surface of the cornified envelope. The CLE is essential for proper barrier function of the skin and is derived from linoleate-rich acylglucosylceramides synthesized in the viable epidermis. Biosynthesis of acylglucosylceramide and its conversion to the cornified envelope is complex. Acylglucosylceramide in the bounding membrane of the lamellar granule is the precursor of the CLE. The acylglucosylceramide in the limiting membrane of the lamellar granule may be oriented with the glucosyl moiety on the inside. Conversion of the acylglucosylceramide to the CLE requires removal of the glucose by action of a glucocerebrosidase. The ester-linked fatty acid may be removed by an as yet unidentified esterase, and the resulting ω-hydroxyceramide may become ester linked to the outer surface of the cornified envelope through action of transglutaminase 1. Prior to removal of ester-linked fatty acids, linoleate is oxidized to an epoxy alcohol through action of 2 lipoxygenases. This can be further oxidized to an epoxy-enone, which can spontaneously attach to the cornified envelope through Schiff’s base formation. Mutations of genes coding for enzymes involved in biosynthesis of the CLE result in ichthyosis, often accompanied by neurologic dysfunction. The CLE is recognized as essential for barrier function of skin, but many questions about details of this essentiality remain. What are the relative roles of the 2 mechanisms of lipid attachment? What is the orientation of acylglucosylceramide in the bounding membrane of lamellar granules? Some evidence supports a role for CLE as a scaffold upon which intercellular lamellae unfold, but other evidence does not support this role. There is also controversial evidence for a role in stratum corneum cohesion. Evidence is presented to suggest that covalently bound ω-hydroxyceramides serve as a reservoir for free sphingosine that can serve in communicating with the viable epidermis and act as a potent broad-acting antimicrobial at the skin surface. Many questions remain.

Evaluation of the molecular lipid organization in millimeter-sized stratum corneum by synchrotron X-ray diffraction

2018 ◽  
Vol 24 (4) ◽  
pp. 621-629 ◽  
Author(s):  
T. Suzuki ◽  
T. Uchino ◽  
I. Hatta ◽  
Y. Miyazaki ◽  
S. Kato ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lipid Organization

Studies in fleece-rot of sheep.

1953 ◽  
Vol 4 (4) ◽  
pp. 430 ◽  
Author(s):  
RH Hayman
Keyword(s):  
Microscopic Examination ◽  
Similar Condition ◽  
Unit Area ◽  
Skin Surface ◽  
Climatic Conditions ◽  
Field Station ◽  
Merino Sheep ◽  
Naturally Occurring ◽  
Sufficient Intensity ◽  
Experimentally Induced

Occasions of unduly heavy and prolonged rainfall during the period April 1946 – July 1951 resulted in the occurrence of fleece-rot in sheep of the Field Station flock in each of the six years. Data obtained from periodic examinations of the flock have been related to the nature of climatic conditions associated with outbreaks of the disease. They show that when rain occurs in falls of sufficient intensity and frequency to wet sheep to the skin for a period of a week or more, fleece-rot may be expected to develop in some of them. The longer the period for which the sheep are kept wet, the greater the number in a flock which will be affected. Fleece-rot was experimentally induced in four out of five Merino sheep known to be susceptible to the condition, whereas five animals known to be resistant were unaffected by the same treatment. Microscopic examination of skin sections taken from naturally occurring cases revealed the presence of a dermatitis. A similar condition was observed in skin sections from the animals in which fleece-rot was experimentally induced. Young sheep were found to be more susceptible than old. There was no association between degree of wrinkling and susceptibility or between 'grip' and susceptibility. When subjectively-appraised attributes of the fleece were related to the occurrence of fleece-rot, confusing results were obtained. However, when measured fleece data, obtained from a group of Merino sheep which had been under observation for four consecutive years, were considered, it was found that those for clean-scoured yield, wax and suint ratio, and density of fibre population per unit area of skin surface, were related to resistance or susceptibility. Nevertheless, a number of animals were found which were susceptible or resistant to the disease despite the nature of their fleece attributes. Differences in susceptibility were found between families of Merino sheep. These are associated with between-family differences for the fleece attributes found to be important in fleece-rot reaction.

Hebb-Type Dynamics is Sufficient to Account for the Inverse Magnification Rule in Cortical Somatotopy

1990 ◽  
Vol 2 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Kamil A. Grajski ◽  
Michael M. Merzenich
Keyword(s):  
Computer Simulation ◽  
Receptive Field ◽  
Cortical Neuron ◽  
Inverse Relationship ◽  
Unit Area ◽  
Skin Surface ◽  
Field Size ◽  
Synaptic Modification ◽  
Somatotopic Map ◽  
Cortical Magnification

The inverse magnification rule in cortical somatotopy is the experimentally derived inverse relationship between cortical magnification (area of somatotopic map representing a unit area of skin surface) and receptive field size (area of restricted skin surface driving a cortical neuron). We show by computer simulation of a simple, multilayer model that Hebb-type synaptic modification subject to competitive constraints is sufficient to account for the inverse magnification rule.

scholarly journals Interaction between SARS-CoV-2 spike glycoprotein and human skin models: a molecular dynamics study

2021 ◽  
Author(s):  
Marc Domingo ◽  
Jordi Faraudo
Keyword(s):  
Stratum Corneum ◽  
Human Skin ◽  
Skin Surface ◽  
Viral Envelope ◽  
Solid Surfaces ◽  
Spike Glycoprotein ◽  
Indirect Transmission ◽  
Physico Chemical ◽  
Human Skin Models ◽  
Structure Orientation

The possibility of contamination of human skin by infectious virions plays an important role in indirect transmission of respiratory viruses but little is known about the fundamental physico-chemical aspects of the virus-skin interactions. In the case of coronaviruses, the interaction with surfaces (including the skin surface) is mediated by their large glycoprotein spikes that protrude from (and cover) the viral envelope. Here, we perform all atomic simulations between the SARS-CoV-2 spike glycoprotein and human skin models. We consider an "oily" skin covered by sebum and a "clean" skin exposing the stratum corneum. The simulations show that the spike tries to maximize the contacts with stratum corneum lipids, particularly ceramides, with substantial hydrogen bonding. In the case of "oily" skin, the spike is able to retain its structure, orientation and hydration over sebum with little interaction with sebum components. Comparison of these results with our previous simulations of the interaction of SARS-CoV-2 spike with hydrophilic and hydrophobic solid surfaces, suggests that the"soft" or "hard" nature of the surface plays an essential role in the interaction of the spike protein with materials.

AN ABNORMALITY OF KERATIN IN THE HARLEQUIN FETUS

PEDIATRICS ◽  
1970 ◽  
Vol 46 (3) ◽  
pp. 437-440
Author(s):  
John M. Craig ◽  
Lowell A. Goldsmith ◽  
Howard P. Baden
Keyword(s):  
Family History ◽  
Stratum Corneum ◽  
Diffraction Analysis ◽  
Thymus Gland ◽  
Horny Layer ◽  
X Ray Diffraction ◽  
Epithelial Surface ◽  
Negative Family History ◽  
X Ray ◽  
Fibrous Protein

A harlequin fetus was born to unrelated parents with a negative family history for any form of ichthyosis. The child was grossly deformed, showing thick plaques on the cutaneous surface, and survived only 48 hours. Pathological studies of the skin showed marked thickening of the stratum corneum, but no other distinctive changes. X-ray diffraction analysis of the horny layer revealed the presence of a cross-β fibrous protein rather than the usual α-protein. The epithelial surface of other organs appeared normal. The thymus gland was involuted and showed changes in the corpuscles. Abnormalities were also observed in the conversion of cartilage to bone.

Epidermal thermal conductivity and stratum corneum hydration in cat footpad

1975 ◽  
Vol 228 (6) ◽  
pp. 1903-1908 ◽  
Author(s):  
KR Holmes ◽  
T Adams
Keyword(s):  
Thermal Conductivity ◽  
Stratum Corneum ◽  
Water Content ◽  
Skin Surface ◽  
Blocking Agent ◽  
Eccrine Sweat Gland ◽  
Dermoepidermal Junction ◽  
Stratum Corneum Hydration ◽  
Cutaneous Vasoconstriction ◽  
Stratum Corneum Water Content

Epidermal thermal conductivity (k) was calculated for the cat footpad by measuringtransepidermal heat flux and temperature gradient ( inverted question markT) while changes in stratum corneum water content were produced by "internal hydration" (IH; eccrine sweat gland activity by nerve stimulation) or by "external hydration" (HH; exposure to air saturated with water vapor). In some experiments, cutaneous vasoconstriction accompanying IH was prevented by an alpha-adrenergic receptor blocking agent, phenoxybenzamine (POB), 3.52 mg/kg iv. For dry skin k=0.167 plus or minus 0.023 (SE) W.m (-1) degree C (-1). With and without POB, IH produced 49.5% and 17.2% increases in k, respectively; HH after IH did not increase k more. With POB, IH increased k more than did HH alone (49.5% and 15.5%, respectively) and at a higher rate (4.22 times 10 minus 3 and 0.63 times 10 minus 3 W.m minus 1.degree C minus 1. min minus 1, respectively.) As k increased, usually deltaT decreased. Increasing k and decreasing deltaT with skin hydration explain the phenominon that air temperature is felt to be lower the more humid a cold exposure, since the temperature of thermoreceptors at the dermoepidermal junction is closer to that of the skin surface when the corneum is hydrated than when it has a low water content.

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