A high concentration of Merkel cells in the bulge prior to the attachment of the arrector pili muscle and the formation of the perifollicular nerve plexus in human fetal skin

1993 ◽  
Vol 285 (5) ◽  
pp. 261-268 ◽  
Author(s):  
Y. Narisawa ◽  
K. Hashimoto ◽  
Y. Nakamura ◽  
H. Kohda
Keyword(s):  
Nerve Plexus ◽  
Merkel Cells ◽  
Fetal Skin ◽  
High Concentration ◽  
Arrector Pili Muscle

scholarly journals Biological significance of dermal Merkel cells in development of cutaneous nerves in human fetal skin.

1992 ◽  
Vol 40 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Y Narisawa ◽  
K Hashimoto ◽  
Y Nihei ◽  
T Pietruk
Keyword(s):  
Monoclonal Antibodies ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Fetal Development ◽  
Epithelial Membrane Antigen ◽  
Biological Significance ◽  
Nerve Plexus ◽  
Merkel Cells ◽  
Fetal Skin ◽  
Nerve Growth Factor Receptors

We detected epidermal Merkel cells in 12-week fetuses with monoclonal antibodies (MAb) against simple epithelium keratin and epithelial membrane antigen. In 15-week fetuses these Merkel cells began to descend into the dermis and expressed nerve growth factor receptors (NGF-R). At approximately the same time, cutaneous nerves, as detected with an MAb against neurofilaments, extended from the subcutaneous trunk and branched to form the subepidermal nerve plexus. The expression of NGF-R on dermal Merkel cells preceded their connection with immunoreactive small nerves. Initially, most of these fine nerve endings were directed towards dermal Merkel cells. In 23-week fetuses the subepidermal nerve plexus was well developed and immunoreactive dermal Merkel cells began to disappear. At all stage of fetal development the epidermal Merkel cells did not strongly express NGF-R. We postulate that dermal Merkel cells play an inductive and a promotional role in development of the cutaneous nerve plexus in the upper dermis.

Merkel cells participate in the induction and alignment of epidermal ends of arrector pili muscles of human fetal skin

1996 ◽  
Vol 134 (3) ◽  
pp. 494-498 ◽  
Author(s):  
Y. NARISAWA ◽  
K. HASHIMOTO ◽  
H. KOHDA
Keyword(s):  
Merkel Cells ◽  
Fetal Skin

Intraepidermal Formation of Merkel Cells in Xenografts of Human Fetal Skin

1990 ◽  
Vol 94 (3) ◽  
pp. 359-364 ◽  
Author(s):  
Ingrid Moll ◽  
Alfred T. Lane ◽  
Werner W. Franke ◽  
Roland Moll
Keyword(s):  
Merkel Cells ◽  
Fetal Skin

Formation of Epidermal and Dermal Merkel Cells During Human Fetal Skin Development

1986 ◽  
Vol 87 (6) ◽  
pp. 779-787 ◽  
Author(s):  
Ingrid Moll ◽  
Roland Moll ◽  
Werner W Franke
Keyword(s):  
Merkel Cells ◽  
Fetal Skin ◽  
Skin Development

Merkel cells participate in the induction and alignment of epidermal ends of arrector pili muscles of human fetal skin

1996 ◽  
Vol 134 (3) ◽  
pp. 494-498 ◽  
Author(s):  
Y. NARISAWA ◽  
K. HASHIMOTO ◽  
H. KOHDA
Keyword(s):  
Merkel Cells ◽  
Fetal Skin

Cytomembrane Preservation in Tissue Dehydrated Only With Glutaraldehyde and Epon 812 Resin

1973 ◽  
Vol 31 ◽  
pp. 320-321
Author(s):  
Daniel C. Pease
Keyword(s):  
Diffraction Pattern ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Unpublished Study ◽  
X Ray ◽  
Sectioned Material

A previous study demonstrated that tissue could be successfully infiltrated with 50% glutaraldehyde, and then subsequently polymerized with urea to create an embedment which retained cytomembrane lipids in sectioned material. As a result, the 180-190 Å periodicity characteristic of fresh, mammalian myelin was preserved in sections, as was a brilliant birefringence, and the capacity to bind OsO4 vapor in the hydrophobic bilayers. An associated (unpublished) study, carried out in co-operation with Drs. C.K. Akers and D.F. Parsons, demonstrated that the high concentration of glutaraldehyde (and urea) did not significantly alter the X-ray diffraction pattern of aldehyde-fixed, myelin. Thus, by itself, 50% glutaraldehyde has little effect upon cytomembrane systems and can be used with confidence for the first stages of dehydration.

Effects of carbamylcholine on chick embryo aggregate retina cell cultures

1988 ◽  
Vol 46 ◽  
pp. 350-351
Author(s):  
Glenn M. Cohen ◽  
Radharaman Ray
Keyword(s):  
Cell Cultures ◽  
Single Cells ◽  
Retinal Cell ◽  
Cell Aggregates ◽  
High Concentration ◽  
In Ovo ◽  
Sterile Culture ◽  
Retinal Tissue ◽  
Synaptic Junctions ◽  
And Control

Retinal,cell aggregates develop in culture in a pattern similar to the in ovo retina, forming neurites first and then synapses. In the present study, we continuously exposed chick retinal cell aggregates to a high concentration (1 mM) of carbamylcholine (carbachol), an acetylcholine (ACh) analog that resists hydrolysis by acetylcholinesterase (AChE). This situation is similar to organophosphorus anticholinesterase poisoning in which the ACh level is elevated at synaptic junctions due to inhibition of AChE, Our objective was to determine whether continuous carbachol exposure either damaged cholino- ceptive neurites, cell bodies, and synaptic elements of the aggregates or influenced (hastened or retarded) their development.The retinal tissue was isolated aseptically from 11 day embryonic White Leghorn chicks and then enzymatically (trypsin) and mechanically (trituration) dissociated into single cells. After washing the cells by repeated suspension and low (about 200 x G) centrifugation twice, aggregate cell cultures (about l0 cells/culture) were initiated in 1.5 ml medium (BME, GIBCO) in 35 mm sterile culture dishes and maintained as experimental (containing 10-3 M carbachol) and control specimens.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

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