The Pre-Natal Development of Skin and Hair in Cattle II. Bos Indicus l. X B. Taurus l.

Lyne, A. G.; Heideman, Margaret J

doi:10.1071/bi9600584

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…Another possibility is that the retardation of hair growth in mice occurred as a consequence of the EGFinduced delay in normal development of the skin after birth. A cyclical relationship between the structure of the skin and hair growth was proposed by Chase et al (19531, who described a thinning of the epidermis during the first week of follicle development, accompanied by increases in the thickness of the dermis and adipose layers (see also Lyne and Heideman, 1959). These features were maintained during the period of follicle growth and hair proliferation, but reverted to their original conformation when the follicles entered the telogen phase.…”

Section: Discussionmentioning

confidence: 89%

Epidermal growth factor delays the development of the epidermis and hair follicles of mice during growth of the first coat

1983

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The structure of the epidermis and hair-follicle bulbs and the proliferative activities of their component cells were studied in the midside skin of male mice treated with epidermal growth factor (EGF) or saline during formation of the first coat (days 0-21). The epidermis was thickest at birth, but in control animals became progressively thinner as cell size and the number of layers of granular and cornified cells were reduced. EGF treatment from birth resulted in a thickening of the epidermis at 5 days of age, and at 5 and 8 days the histological appearance was strikingly similar to that on the day of birth. At 12 and 21 days the structure of the epidermis of EGF-treated mice more closely resembled that of contemporaneous controls. The mitotic and labeling indices of the basal cells of control epidermis declined throughout the sampling period from peak values on the day of birth. By contrast, these indices were maintained at birth levels in EGF-treated mice for 8 days before declining to approximate those of controls at 12 and 21 days.Hair growth rate was inhibited and hair diameter reduced in EGF-treated mice (Moore et al., 1981a). These observations were reflected in changes in the follicle bulb. Both the growth of the bulb and the increase in numbers of bulb cells observed during the early part of the anagen phase were inhibited by EGF. However, neither the size of the dermal papilla nor the numbers of papilla cells were significantly altered in treated animals. The mitotic index of the bulb cell population declined during the sampling period in both experimental and control groups. However, the labeling index of bulb cells of EGF-treated mice was significantly increased over contemporaneous control values on days 8 and 12. Rather than stimulating epidermal growth during the early postnatal period, these observations indicate that EGF delays the normal process of skin development by maintaining the proliferative and differentiation processes active in the cell populations at the time of birth. As a consequence of this, follicle development and hair growth are inhibited. Levi-Montalcini and Cohen (1960) and Cohen and Elliott (1963) reported that a submaxillary gland protein, epidermal growth factor (EGF), promoted the keratinization of cells of the epidermis when administered to mice after birth, but inhibited hair growth. The apparent discrepancy between the responses of the cells of the epidermis on one hand and those of the epidermal derivatives, the hair follicles, on the other, has not been studied in any detail. Recently, we examined one aspect of this in a study of the monotrichs of the first hair coat in mice. Daily injections of EGF from birth resulted in the development of curved fibers and caused a retardation of length growth rate and a reduction in hair diameter (Moore et al., 1981a). In this report we have compared the morphology and proliferative activities of cell populations of the epidermis and hair-follicle bulbs in EGF-treated and control mice during the growth of the hair coat, wh...

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Section: Discussionmentioning

confidence: 89%

Epidermal growth factor delays the development of the epidermis and hair follicles of mice during growth of the first coat

1983

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“…The follicle terminology is essentially that used by Lyne (1957a) for bandicoots, and the stages of follicle development are based on those described by Hardy and Lyne (1956) and Lyne and Heideman (1959). The various stages are: 0, no follicles; 1, follicle plug; 2, pre-papilla; 3, papilla; 4, hair cone; 5, advanced hair cone; 6, hair tip keratinized; 7, hair tip in epidermis; 8, hair tip emerged; 8+, hair growth; 10c, resting phase.…”

Section: Methodsmentioning

confidence: 99%

“…Stage 1 is divided into la, when the length of the plug is less than its diameter, and lb, when the length is equal to or greater than the diameter. Beyond stage 8, four stages (9, lOa, lOb, and lOc) of follicle development were used by Lyne and Heideman (1959). For convenience only two stages are used in the present study.…”

Section: Methodsmentioning

confidence: 99%

The Development of Hair Follicles in the Marsupial Trichosurus Vulpecula

Lyne¹

1970

Aust. Jnl. Of Bio. Sci.

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SummaryThe development of hair follicl'3s in the brush-tailed possum T. vulpecula has been studied in skin samples from animals ranging in age from embryos to adults. The first follicles appear at about 2 days after birth and develop rapidly, producing minute non-medullated hairs (about 0·5 mm long) during the first hair cycle. After the formation of these hairs, further follicles are initiated and these grow larger medullated hairs (up to about 2·0 em in length).Groups of follicles are formed and within each group the following follicles may be distinguished: a single original central primary follicle (two populations are recognized), a pair of original lateral primary follicles, and usually one or two original secondary follicles. All of these follicle types arise directly from the epidermis and open independently on the skin surface. Additional follicles, referred to as derived follicles, develop by branching from the original follicles and they share a common orifice with their parent follicles. The first-formed population of original central primary follicles, however, does not branch.Special features in the development of the different types of follicles are described and their rates of development are compared. All central and most lateral primary follicles develop sweat glands. The development of the sweat glands of the first-formed population of central primary follicles is retarded until these follicles reach the end of the first period of hair growth.The manner in which the hair follicles are formed and other features in the development of the coat in T. vulpecula are compared with those in other mammals.

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“…This phenomenon is also seen to some extent in the mouse (Slee 1962). In the ox (Lyne and Heideman 1959) the epidermis increases and then decreases in thickness during foetal life, with follicle initiation coinciding with the period of increasing thickness.…”

Section: Discussionmentioning

confidence: 99%

Development of the Epidermis of the Marsupial Trichosurus Vulpecula

Downes¹,

Reis²,

Sharry³

et al. 1970

Aust. Jnl. Of Bio. Sci.

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Development of the epidermis has been studied in the brush�tailed possum T. vulpecula. Although the epidermis is thin at birth (about 12 !Lm), there is a four� to fivefold increase in epidermal thickness during the first 21 days after birth. However, when the young first emerge from the pouch, at about 120 days, the epidermis has returned to the thickness seen at birth. The thickness in adults is usually about 15 !Lm. Hair follicles differentiate from the epidermis of pouch young throughout the period of increasing epidermal thickness and during most of the subsequent period of decreasing thickness.

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The Pre-Natal Development of Skin and Hair in Cattle II. Bos Indicus l. X B. Taurus l.

Abstract: A histological study has been made of the development of the skin and hair follicles in 22 crossbred (Brahman X Hereford or Brahman X Shorthorn) cattle foetuses, ranging in age from 77 to 263 days, and in three new�born calves.

Cited by 6 publications

References 7 publications

Epidermal growth factor delays the development of the epidermis and hair follicles of mice during growth of the first coat

Epidermal growth factor delays the development of the epidermis and hair follicles of mice during growth of the first coat

The Development of Hair Follicles in the Marsupial Trichosurus Vulpecula

Development of the Epidermis of the Marsupial Trichosurus Vulpecula

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