A quantitative study of hair growth using mouse and rat vibrissal follicles

Development ◽  
1982 ◽  
Vol 72 (1) ◽  
pp. 209-224
Author(s):  
Lamees Ibrahim ◽  
E. A. Wright
Keyword(s):  
Linear Relationship ◽  
Quantitative Study ◽  
Hair Growth ◽  
Dermal Papilla ◽  
Positive Linear Relationship ◽  
Rats And Mice ◽  
Relationship Of ◽  
Dermal Papillae

The volumes of the dermal papilla, matrix and fully grown hair of vibrissal follicles of rats and mice were measured. Dermal papillae were surgically removed from rats' vibrissal follicles and a small new dermal papilla was always reformed. The lower third of rats and mice follicles, containing the whole of the dermal papilla was amputated and very small dermal papillae were reformed. Follicles containing small dermal papillae produced small hairs and a constant positive linear relationship of 7·0 was found between the volume of the dermal papilla and the volume of the full-grown hair for all cases studied.

Restoration of hair growth by surgical implantation of follicular dermal sheath

Development ◽  
1992 ◽  
Vol 116 (3) ◽  
pp. 563-571 ◽  
Author(s):  
K.A. Horne ◽  
C.A. Jahoda
Keyword(s):  
Histological Examination ◽  
Hair Growth ◽  
Dermal Papilla ◽  
Cell Replacement ◽  
Sequence Of Events ◽  
Surgical Implantation ◽  
Immense Potential ◽  
Dermal Papillae ◽  
Do So ◽  
Sheath Cells

The capacity of lower follicle dermal sheath to restore hair growth was tested by removing the lower halves of follicles, and then immediately implanting material containing dermal sheath cells from these bases, into the remaining upper epidermal follicle cavity. Over 60% of recipient follicles produced stout emergent vibrissa fibres and some operations resulted in multiple hair production from a single follicle. Histological examination revealed new dermal papillae within large bulb structures which were sited below the level of amputation--a feature that indicated that the new dermal papilla was derived from implanted material. For many follicles, the failure to produce emergent fibres could be accounted for after histological examination. These results provide clear evidence that lower follicle dermal sheath cells are capable of replacing those of the dermal papilla and it shows that they can do so in the context of the upper follicle. However, because elements of lower follicle epidermis were present in the implant material, the interactive sequence of events cannot be established. Dermal sheath cells have immense potential for papilla cell replacement: questions remain as to whether the distinction between sheath and papilla cells is one of context, or whether the transition requires specific external influences.

Development of horns in merino sheep

1973 ◽  
Vol 21 (2) ◽  
pp. 153 ◽  
Author(s):  
AG Lyne ◽  
DE Hollis
Keyword(s):  
Hair Growth ◽  
Dermal Papilla ◽  
Hair Follicles ◽  
Sweat Glands ◽  
Sebaceous Glands ◽  
Merino Sheep ◽  
Female Foetus ◽  
Connective Tissue Sheath ◽  
Hair Formation ◽  
Dermal Papillae

Development of horns has been studied in 20 foetuses ranging in age from 55 to 144 days of gestation, and in 16 lambs, ranging in age from birth to 42 days. Samples from one adult have also been examined. An increase in the thickness of the epidermis appears to be the first indication of horn development, recognizable in a 75-day-old male foetus and in an 84-day-old female foetus. Primary hair follicles develop in the horn region and produce emerging hairs, but these follicles later degenerate and disappear. The sweat glands and sebaceous glands formed in association with these follicles also degenerate, usually after hair growth has ceased. Fusion of primary follicles is a common feature in the horn growing skin, particularly before hair formation; a common connective tissue sheath surrounds the lower parts of these fused follicles. No secondary follicles are formed in the horn region but some branching of the primary follicles has been observed. By 118 days of gestation the epidermis in the horn region becomes greatly thickened, with very long dermal papillae which are well vascularized and innervated. Medulla-like columns of cells are formed above each dermal papilla and these cells keratinize later than the cells between the columns. These medullary cells remain in contact with each other longer than do the other cells of the horny sheath. Numerous arteriovenous anastomoses, which develop at two levels in the dermis of the horn region, are in continuity with capillaries which enter the dermal papillae of the epidermis. An outgrowth of bone from the frontal region of the skull, which later becomes the bony core of the horn, is first seen in a male foetus at 118 days. Acetylcholinesterase-positive branched cells (Langerhans cells), present in the lower part of the thick epidermis of developing horns, are not discernible in fully formed horns.

Relationship of Task Success to Task Liking: A Replication

1966 ◽  
Vol 18 (2) ◽  
pp. 552-554 ◽  
Author(s):  
Edwin A. Locke
Keyword(s):  
Linear Relationship ◽  
Repeated Measures ◽  
Positive Linear Relationship ◽  
Repeated Measures Design ◽  
Task Success ◽  
Relationship Of

Two experiments, using a repeated measures design, were performed to test the hypothesis of a positive, linear relationship between degree of success on a task and liking for the task. The hypothesis was confirmed, thus replicating previous results obtained using a randomized groups design.

The induction of hair follicle formation in the adult hooded rat by vibrissa dermal papillae

Development ◽  
1970 ◽  
Vol 23 (1) ◽  
pp. 219-236
Author(s):  
R. F. Oliver
Keyword(s):  
Hair Follicle ◽  
Hair Growth ◽  
Dermal Papilla ◽  
Hair Shaft ◽  
Hair Follicles ◽  
Hair Cycle ◽  
Hair Bulb ◽  
Essential Component ◽  
Dermal Papillae

Hair follicles are essentially composed of two tissues. The inner epidermal component, which gives rise to, among other products, the keratinized hair shaft, is confluent with the surface epidermis and is ensheathed by the dermal component which is confluent with the pars papillaris of the dermis. A specialization of the dermal component is the dermal papilla which, in follicles producing hair, is enclosed by the epidermal matrix of the hair bulb and is connected to the dermal sheath by the papilla stalk. Many authorities have considered that the dermal papilla is an essential component of the hair follicle (reviews: Cohen, 1965; Oliver, 1969). It has been suggested that the dermal papilla may be involved in both the induction of follicle lengthening and hair growth during the proanagen phase (Chase, 1965) of the hair cycle, a concept now justified by direct experimentation in the vibrissa follicle at least (Oliver, 1967b), and perhaps also in determining the nature of the hair produced by a follicle.

scholarly journals Non-linear relationship of cell hit and transformation probabilities in a low dose of inhaled radon progenies

2009 ◽  
Vol 29 (2) ◽  
pp. 147-162 ◽  
Author(s):  
Imre Balásházy ◽  
Árpád Farkas ◽  
Balázs Gergely Madas ◽  
Werner Hofmann
Keyword(s):  
Linear Relationship ◽  
Low Dose ◽  
Non Linear ◽  
Relationship Of

Hormones and Hair Growth: Variations in Androgen Receptor Content of Dermal papilla Cells Cultured from Human and Red Deer (Cervus Elaphus) Hair Follicles.

1993 ◽  
Vol 101 (s1) ◽  
pp. 114S-120S ◽  
Author(s):  
Valerie Anne Randall ◽  
Margaret Julie Thornton ◽  
Andrew Guy Messenger ◽  
Nigel Andrew Hibberts ◽  
Andrew Stewart Irving Loudon ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Cervus Elaphus ◽  
Hair Growth ◽  
Red Deer ◽  
Dermal Papilla ◽  
Hair Follicles ◽  
Dermal Papilla Cells ◽  
Cells Cultured

Ectopic regeneration of whiskers in the hooded rat from implanted lengths of vibrissa follicle wall

Development ◽  
1967 ◽  
Vol 17 (1) ◽  
pp. 27-34
Author(s):  
R. F. Oliver
Keyword(s):  
Whisker Growth ◽  
Dermal Papilla ◽  
Regenerative Process ◽  
Upper Lip ◽  
Outer Root Sheath ◽  
Histological Studies ◽  
Root Sheath ◽  
Dermal Cells ◽  
Regenerative Phenomenon ◽  
Dermal Papillae

Previous studies relating to the effect on whisker growth of removal of various components of the whisker follicle have shown that both after removal of the dermal papilla alone and after removal of as much as the lower third of the follicle, regeneration of new dermal papillae and then the generation of whiskers may occur (Oliver, 1966 a, b). Histological studies of this regenerative phenomenon revealed that the outer root sheath became a solid cord or rod of cells and that dermal cells, derived at least in part from the mesenchymal layer, aggregated over the proximal surface of the rod and eventually became the new dermal papilla. To determine whether the regenerative process was dependent on factors present in the local follicle environment on the upper lip, lengths of isolated follicle wall (‘follicle tubes’) composed of the outer root sheath and the adherent mesenchymal layer were transplanted as autografts to ascertain whether they could regenerate dermal papillae and fibres in another site.

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