Proliferative Cycle and Fate of Cell Nuclei in Wool Follicles

Downes, AM; Chapman, Ralph E.; Till, A. R.; Pa, Wilson

doi:10.1038/212477a0

Cited by 37 publications

(8 citation statements)

References 9 publications

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“…The last authors also reported that cells destined to differentiate into the root sheaths and fibre began to withdraw from around the dermal papilla on about day 6. Downes et al (1966) have shown that [3H]thymidine that was incorporated into cell nuclei during the wool growth in a Merino was lost about 3 days later during keratinization. The reduction of DNA content of skin between days 4 and 8 in skin (Fig.…”

Section: Discussionmentioning

confidence: 99%

Some Effects of Dexamethasone on Nucleic Acid Metabolism in Skin of Merino Sheep

Panaretto¹,

Leish²,

Donnelly³

1982

Aust. Jnl. Of Bio. Sci.

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Section: Discussionmentioning

confidence: 99%

Some Effects of Dexamethasone on Nucleic Acid Metabolism in Skin of Merino Sheep

Panaretto¹,

Leish²,

Donnelly³

1982

Aust. Jnl. Of Bio. Sci.

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“…Therefore, we cannot as yet exclude that at least some of the DNA resides within the lipid-rich epidermal detritus on the hair surface which contains skin flakes and dandruff. Downes et al [3] labelled hair follicle DNA of sheep by intradermal injection of [3H]thymidine. They established that all nucleic acids degrade during keratinization.…”

Section: Discussionmentioning

confidence: 99%

“…It has been suggested that both DNA and RNA completely degenerate in the initial phase of keratinization of hair follicle cells [3]. Gill et al [4] failed to extract DNA for forensic paternity analysis from human hairs.…”

Section: Introductionmentioning

confidence: 99%

The extraction of high‐molecular‐mass DNA from hair shafts

et al. 1988

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“…When this procedure is used after injection of labelled thymidine in sheep the specific activity of the wool root material rises to a maximum and then declines because much of the radioactive material is removed when cell nuclei in the fibre are degraded during keratinization (Downes et al 1966). By contrast, when [ 35 S]cystine is injected, the specific activity of plucked fibres rises to an almost steady value during the next few days because the cystine is retained in the fibres (Downes 1965).…”

Section: Introductionmentioning

confidence: 99%

“…This procedure has been used to study events within the proximal portions of hair follicles (Cattaneo et al 1961; McCarter and QuastIer 1962; Smoliar 1966; Epstein and Maibach 1969), and some aspects of cell proliferation, migration and sloughing in wool follicles (Downes et al 1966;Chapman 1971; Vsevolodov and Prusova 1976).…”

Section: Introductionmentioning

confidence: 99%

Migration and Keratinization of Cells in Wool Follicles

Chapman¹,

Downes²,

Pa³

1980

Aust. Jnl. Of Bio. Sci.

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. .Migration of' cells in wool follicles of an adult Merino sheep was studied autoradiographically in skin samples taken at intervals after an intravenous injection of [3Hjthymidine. Fibre arid inner root sheath cells incorporated [3Hjthymidine in a cone-shaped region of the follicle bulb. Labelled inner sheath cells migrated out of the bulb ahead of contemporaneous cells in the fibre and remained in advance, although to a progressively lesser extent, until the inner sheath cells sloughed into the follicle lumen. Outer root sheath cells incorporated [3Hjthymidine along the length of the follicle. Cells in the proximal half of the outer sheath migrated inwards and distally and sloughed into the follicle lumen before contemporaneous inner sheath cells. Other cells in the distal half of the outer sheath migrated past the level where cells from the proximal population were shed and also sloughed into the lumen. In the most distal part of the outer sheath, which formed the epidermis-like lining of the follicle canal, little migration of cells was observed during 8 days of observation.The specific activity of tritium in fibres plucked from the same sheep at intervals after the intravenous injection of [3Hjthymidine was determined by scintillation counting and assessed in terms of cell migration and hardening of the fibres. The time at which the specific activity of solventdegreased fibres reached a maximum was found to give an estimate of the time for cells in the fibre to migrate to the upper limit of the keratogenous zone. When the plucked fibres were extracted with 8 M urea the times of the maximum specific activities of the urea-dispersible and urea-insoluble material provided respectively estimates of the times at which hardening of the fibres began and ended.The effects of different planes of nutrition were examined in two other Merino sheep by radioassay· of fibres plucked after intravenous injections of [3Hjthymidine given after an equilibration period of at least 2 months on each level of feeding. A high plane of nutrition increased the rate of cell migration and hastened the onset of hardening of the fibres, but prolonged the hardening process. The prolongation of the hardening process was confirmed by the specific activities of fibres plucked after intravenous inje,

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Proliferative Cycle and Fate of Cell Nuclei in Wool Follicles

Cited by 37 publications

References 9 publications

Some Effects of Dexamethasone on Nucleic Acid Metabolism in Skin of Merino Sheep

Some Effects of Dexamethasone on Nucleic Acid Metabolism in Skin of Merino Sheep

The extraction of high‐molecular‐mass DNA from hair shafts

Migration and Keratinization of Cells in Wool Follicles

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