An Ultrastructural Study of the Membranes of Keratinizing Wool Follicle Cells

1972 ◽  
Vol 11 (1) ◽  
pp. 205-219
Author(s):  
D. F. G. ORWIN ◽  
R. W. THOMSON
Keyword(s):  
Hair Follicle ◽  
Ultrastructural Study ◽  
Plasma Membranes ◽  
Follicle Cells ◽  
Intercellular Spaces ◽  
Membrane Complex ◽  
Cytoplasmic Material ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Wool Follicle

Measurements of the widths of apposed plasma membranes and of the spaces between them were made at different stages of differentiation of keratinizing and hardening cells of the wool follicle. In contrast to findings in the hair follicle, no changes were detected for apposed cortex, cortex/fibre cuticle and fibre cuticle/fibre cuticle cells until keratinization had taken place. The trilaminar appearance of the plasma membranes was then lost and the intercellular material decreased in width. However, the inner root sheath cells developed a ‘membrane complex’ in enlarged intercellular spaces prior to hardening. Desmosomes are apparently retained in the hardened ‘membrane complexes’. A band of cytoplasmic material was also formed adjacent to the inner lamellae of the plasma membranes immediately before hardening of the cells. The presence of gap and tight junctions in differentiating cell lines of the wool follicle was noted.

scholarly journals THE ELECTRON MICROSCOPY OF THE HUMAN HAIR FOLLICLE

1957 ◽  
Vol 3 (2) ◽  
pp. 223-230 ◽  
Author(s):  
M. S. C. Birbeck ◽  
E. H. Mercer
Keyword(s):  
Hair Follicle ◽  
Cross Sections ◽  
Plasma Membranes ◽  
Membrane Complex ◽  
Outer Sheath ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Cell Layers ◽  
Adhesive Contacts ◽  
Similar Complex

1. The three cylinders of cells, each one cell thick, which together constitute the inner root sheath, arise from the peripheral portions of the undifferentiated matrix. These cells, like the hair cuticle, are stabilised by the spread of adhesive contacts between their plasma membranes which occurs in the mid-bulb and upper bulb of the hair follicle. 2. The characteristic intracellular product of all three cell layers is trichohyaline. This substance is formed in the first place as amorphous droplets which subsequently transform into a birefringent form. 3. This transformation, involving the formation of a birefringent product from an amorphous precursor, is in contrast to the formation in the cortex of keratin which originates in a fibrous form. 4. Trichohyaline appears first and transforms first in the cells of Henle which are nearest the outer sheath and the dermal supply vessels. This transformation occurs at the level of the neck of the follicle. Synthesis and transformation in the cells of Huxley and the sheath cuticle lag behind the similar events in the cells of Henle. The transformation does not begin until the lower prekeratinous zone in the Huxley and cuticle cells. 5. The amorpous-fibrous transformation occurs rapidly cell by cell and involves the conversion of all the trichohyaline droplets. In longitudinal sections the birefringent modification can be seen extending from the droplets in both directions parallel to the axis of the hair. In cross-sections the images of the transformed material are difficult to interpret. They may be seen as sections of corrugated sheets (∼100 A thick) or condensed fibrils ∼100 A in width. 6. At the same time that the trichohyaline transforms, the spacing between the cell membranes increases and a dark deposit appears centrally between them. This membrane complex, and the similar complex of the hair cuticle cells described in Part 2, may be specialised formations whose purpose is to hold the hardened cells together.

scholarly journals Trichohyalin, an intermediate filament-associated protein of the hair follicle.

1986 ◽  
Vol 102 (4) ◽  
pp. 1419-1429 ◽  
Author(s):  
J A Rothnagel ◽  
G E Rogers
Keyword(s):  
Molecular Weight ◽  
Hair Follicle ◽  
Polyclonal Antibodies ◽  
Side Chain ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Arginine Residues ◽  
Wool Follicle ◽  
Sheep Wool

A precursor protein associated with the formation of the citrulline-containing intermediate filaments of the hair follicle has been isolated and characterized. The protein, with a molecular weight of 190,000, was isolated from sheep wool follicles and purified until it yielded a single band on a SDS polyacrylamide gel. The Mr 190,000 protein has a high content of lysine and glutamic acid/glutamine residues and is rich in arginine residues, some of which, it is postulated, undergo a side chain conversion in situ into citrulline residues. Polyclonal antibodies were raised to the purified protein, and these cross-react with similar proteins from extracts of guinea pig and human follicles and rat vibrissae inner root sheaths. Tissue immunochemical methods have localized the Mr 190,000 protein to the trichohyalin granules of the developing inner root sheath of the wool follicle. We propose that the old term trichohyalin be retained to describe this Mr 190,000 protein. Immunoelectron microscopy has located the Mr 190,000 protein to the trichohyalin granules but not to the newly synthesized filaments. This technique has revealed that trichohyalin becomes associated with the filaments at later stages of development. These results indicate a possible matrix role for trichohyalin.

scholarly journals THE ELECTRON MICROSCOPY OF THE HUMAN HAIR FOLLICLE

1957 ◽  
Vol 3 (2) ◽  
pp. 215-222 ◽  
Author(s):  
M. S. C. Birbeck ◽  
E. H. Mercer
Keyword(s):  
Electron Microscopy ◽  
Hair Follicle ◽  
Late Stage ◽  
Final Stage ◽  
Human Hair ◽  
Plasma Membranes ◽  
Human Hair Follicle ◽  
Laminated Structure ◽  
Root Sheath ◽  
Inner Root Sheath

1. During the early differentiation of the cuticle the cell membranes smooth out and the cells become closely attached over most of their surface. The change seems to be due to a layer of cement which forms between them. The plasma membranes also increase in density. 2. The decreased membrane activity of the cuticle cells may prevent a phagocytosis of the melanocyte processes and thus account for the non-pigmentation of the cuticle. 3. The flattening and imbrication of the cuticle may possibly be explained by a zipper-like spread of cell contacts. 4. Keratinisation of the cuticle occurs at a late stage in its development; the keratin formed is an amorphous type, similar to the γ-fraction of the cortex which is produced at a similar level. 5. Keratinisation is accompanied by the formation of complex intercellular layers similar to structures observed in the inner root sheath (see Part 3). 6. In the final stage of keratinisation the remaining cytoplasm condenses with the result that the cell is divided into a laminated structure with an outer keratinised layer and an inner layer, which is insoluble in keratinolytic solvents.

A Selectable Biomarker in Hair Follicle Cycles – Cathepsins: A Preliminary Study in Murine

2021 ◽  
pp. 1-7
Author(s):  
Jingzhu Bai ◽  
Zijian Gong ◽  
Qingfang Xu ◽  
Haiyan Chen ◽  
Qiaoping Chen ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Hair Cycle ◽  
Biological Factors ◽  
Outer Root Sheath ◽  
Physiological Processes ◽  
Intervention Measures ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Preliminary Study ◽  
Paraffin Method

<b><i>Background/Objective:</i></b> Hair cycle is regulated by many biological factors. Cathepsins are involved in various physiological processes in human skin. Here, we investigated the cathepsin expression and distribution changes in follicular growth cycles for better understanding the hair cycles and to explore new intervention measures. <b><i>Methods:</i></b> The 24 mice (C57BL/6, female, 7-week old) were selected and removed the back hair via rosin/paraffin method. At Day 8, Day 20, and Day 25, biopsy on post-plucking area was done. Immunohistochemical staining, Western blot, and Q-PCR were used to test the cathepsin B/D/L/E. <b><i>Results:</i></b> In anagen, cathepsins (B, D, L, and E) were distributed in the hair follicle matrix, inner hair root sheath, and hair. In catagen, cathepsins were mainly observed in un-apoptosis inner root sheath and outer root sheath. Expression of cathepsins B-mRNA and L-mRNA was decreased from anagen and catagen to telogen. Cathepsin D-mRNA was increased in catagen and then decreased in telogen. Cathepsin E-mRNA was decreased in catagen and slightly increased in telogen. <b><i>Conclusions:</i></b> The distribution and expression of cathepsins B, D, L, and E in hair follicle changed with hair growth process which indicated that cathepsins might act as selectable biomarkers of hair cycle in different stages.

Synthesis of porcine pCLCA2 protein during late differentiation of keratinocytes of epidermis and hair follicle inner root sheath

2012 ◽  
Vol 350 (3) ◽  
pp. 445-453 ◽  
Author(s):  
Stephanie Plog ◽  
Lars Mundhenk ◽  
Lutz Langbein ◽  
Achim D. Gruber
Keyword(s):  
Hair Follicle ◽  
Root Sheath ◽  
Inner Root Sheath

Wool follicle morphology and cell proliferation in New Zealand Romney sheep: a seasonal comparison of fleeceweight-selected and control rams

1994 ◽  
Vol 45 (4) ◽  
pp. 769 ◽  
Author(s):  
SA Holle ◽  
PM Harris ◽  
AS Davies ◽  
MJ Birtles
Keyword(s):  
New Zealand ◽  
Three Dimensional ◽  
Dermal Papilla ◽  
Proliferating Cells ◽  
Root Sheath ◽  
Inner Root Sheath ◽  
Dimensional Measurements ◽  
Wool Follicle ◽  
Seasonal Influences ◽  
And Control

Effects of selection for high fleeceweight in the New Zealand Romney sheep were investigated in relation to the morphology of individual follicles and changes in the germinative cell population of the follicle bulb. Two-year-old Romney rams, 10 from each of two selection lines (Massey University fleeceweight-selected (FWT) and control (CLT) flock), were run together on pasture for a period from June to early December. At three times during this observation period (June, August and November) skin samples were taken from their midside flanks after local injection of bromodeoxyuridine (BrdU), to assess proliferation of bulb cells and several dimensional measurements of the follicle bulb and dermal papilla. FWT sheep had larger follicle dimensions than CLT sheep during winter and summer, with a greater number of proliferating bulb cells. Both flocks showed a seasonal change in follicle size, with a decline during winter, but the size of the dermal papilla was less affected than the germinative tissue area. Measurements of proliferation density (number of proliferating cells per area/volume of bulb tissue) suggest that changes in proliferation density do not contribute to flock differences in fleece production. However, during summer, FWT showed a 40% advantage over CLT sheep in hourly cell production based on data from three dimensional follicle bulb extrapolation. The different genotypes showed variations in width, as well as area of cortex and inner root sheath (IRS), measured across the top of the dermal papilla. The expression of these differences was further enhanced through seasonal influences, suggesting that there is an interaction between genetic/flock influences and seasonal influences on cell distribution to cortex and inner root sheath.

scholarly journals 889 Trpv3 gain-of-function mutation impairs differentiation of hair follicle inner root sheath

2019 ◽  
Vol 139 (5) ◽  
pp. S154
Author(s):  
Z. Song ◽  
X. Chen ◽  
Q. Zhao ◽  
Z. Lin ◽  
S. Yang ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Gain Of Function ◽  
Root Sheath ◽  
Inner Root Sheath
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