Secondary Hair Research Articles

Effects of protected methionine supplementation of the diet and genotype on growth, digestive characteristics and fibre yield in cashmere and angora goats

Methionine is a sulphur-containing essential amino acid which is frequently deficient in animal diets. A number of reports have indicated positive responses to the addition of methionine to the diet of ruminants in the form of protein or the individual amino acid. Protection against degradation by rumen microorganisms is necessary in addition to availability for absorption in the small intestine.The two major genotypes of fine fibre-producing goats are the Angora breed which produce predominantly mohair and those which produce cashmere from secondary hair follicles. Fibre production by primary follicles in Angora goats is limited whereas ‘guard hair’ production in cashmere producers is generally susbtantial.The object of the present study was to compare the response of the two genotypes to the incorporation of a ruminally protected intestinally available methionine supplement in the diet.

Initial responses to selection for fibre value and fibre diameter in cashmere goats

The production of cashmere from goats is one of the most promising options for hill sheep farmers wishing to diversify. Not only is cashmere, the down from the secondary hair follicles, a valuable commodity but goats’ grazing preferences can benefit pasture management and ecology. Because no economically viable breeds of cashmere bearing goats are indigenous to the UK, goats were imported from Iceland, Siberia, Tasmania and New Zealand and an extensive crossbreeding programme involving these genotypes and native feral goats was undertaken to produce genotypes suitable to Scottish conditions (Bishop and Russel, 1994). At the completion of this crossbreeding programme the best means of continued improvement of the existing cashmere goat population was considered to be selection for genetic merit, based on an index combining traits of economic importance. This paper summarises responses to the first two years of this selection.

An investigation of the role of thyroid hormones in the control of secondary fibre growth and moult in cashmere goats

The growth of a fine undercoat (cashmere) in goats is a seasonal phenomenon; growth generally begins during the autumn, continues into the winter and is followed by a moult in the spring. The endocrine mechanisms involved in the control of these processes are unclear but the thyroid hormones have been implicated in the control of fibre growth (Ferguson, Schenckel, Carter and Clarke, 1956; Lincoln, Klandorf and Anderson, 1980) and in the normal seasonal cycle of reproductive activity in sheep (Follett and Potts, 1990). However, it is not known whether or not the thyroid hormones have a role in the mediation of photoperiodic effects on secondary hair follicle activity in goats.Most of the metabolic activity of the thyroid hormones is thought to be attributable to triiodothyronine (T3) which is primarily derived from thyroxine (T4) by a process of monodeiodination. This process can be inhibited by treatment with methylthiouracil.The aim of this study was to suppress the synthesis of T3 and so to determine whether or not it has a direct role in the control of seasonal variation of secondary hair follicle activity and cashmere growth and moulting.

Effects of protected methionine supplementation of the diet and genotype on growth, digestive characteristics and fibre yield in cashmere and angora goats

Methionine is a sulphur-containing essential amino acid which is frequently deficient in animal diets. A number of reports have indicated positive responses to the addition of methionine to the diet of ruminants in the form of protein or the individual amino acid. Protection against degradation by rumen microorganisms is necessary in addition to availability for absorption in the small intestine.The two major genotypes of fine fibre-producing goats are the Angora breed which produce predominantly mohair and those which produce cashmere from secondary hair follicles. Fibre production by primary follicles in Angora goats is limited whereas ‘guard hair’ production in cashmere producers is generally susbtantial.The object of the present study was to compare the response of the two genotypes to the incorporation of a ruminally protected intestinally available methionine supplement in the diet.

An investigation of the role of thyroid hormones in the control of secondary fibre growth and moult in cashmere goats

The growth of a fine undercoat (cashmere) in goats is a seasonal phenomenon; growth generally begins during the autumn, continues into the winter and is followed by a moult in the spring. The endocrine mechanisms involved in the control of these processes are unclear but the thyroid hormones have been implicated in the control of fibre growth (Ferguson, Schenckel, Carter and Clarke, 1956; Lincoln, Klandorf and Anderson, 1980) and in the normal seasonal cycle of reproductive activity in sheep (Follett and Potts, 1990). However, it is not known whether or not the thyroid hormones have a role in the mediation of photoperiodic effects on secondary hair follicle activity in goats.Most of the metabolic activity of the thyroid hormones is thought to be attributable to triiodothyronine (T3) which is primarily derived from thyroxine (T4) by a process of monodeiodination. This process can be inhibited by treatment with methylthiouracil.The aim of this study was to suppress the synthesis of T3 and so to determine whether or not it has a direct role in the control of seasonal variation of secondary hair follicle activity and cashmere growth and moulting.

The role of prolactin in the reactivation of hair follicles in relation to moulting in cashmere goats.

The effects of the suppression or elevation of plasma prolactin concentrations in spring on the timing of the reactivation of the hair follicles and the timing of the spring moult were investigated in cashmere goats. Thirty eight adult female goats, housed under conditions of natural photoperiod at 55 degrees 55'N from mid-December until May, were allocated to four groups starting on 5 January: ten served as untreated controls, eight received 2 mg ovine prolactin subcutaneously every 12 h for 7 weeks (PRL), twelve received 35 mg bromocriptine intramuscularly every 14 days for 17 weeks (BCR) and eight received injections of both ovine prolactin and bromocriptine at the above dose rates for 7 weeks (PRL+BCR). In the PRL group there was an earlier reactivation of the secondary hair follicles (PRL vs control, proportion of secondary follicles in antigen, weeks 1-5, P < 0.01) associated with an earlier moult of secondary fibres (cashmere) but no significant difference in the activity of the primary hair follicles. In the BCR group there was a delay in the reactivation of both the secondary and primary hair follicles (BCR vs control, proportion of secondary and primary hair follicles in anagen, weeks 5-13, P < 0.01) and a delay in the moult. In the PRL+BCR group there was an early reactivation and moult similar to the PRL group. Voluntary food intake (VFI) and liveweight were also measured. Only in the BCR group was there a decrease in VFI compared with the controls but with no effect on liveweight.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of the response of secondary hair follicles of cashmere and angora goats to prolactin and melatonin in vitro

Angora and Cashmere goats produce two distinctive major fibres. The hair coat of the Angora goat consists essentially of a single fleece of Mohair grown by secondary hair follicles with a limited production of guard hair from primary follicles. The average fibre diameter ranges from 22 to 45 urn. In contrast, the Cashmere bearing goat has a double coat comprising coarse guard hair produced by primary follicles with the fine cashmere underhair (preferably 19 μm diameter or less) produced by secondary hair follicles. In the Angora goat, the fibres grow essentially continuously while in cashmere, hair follicle activity is determined largely by seasonal changes in photoperiod. The objective of this study was to investigate the effects of prolactin and melatonin, hormones implicated in the photoperiodic response, on the pattern of growth of secondary hair follicles isolated and maintained in vitro.

In vitroFibre production and protein deposition in secondary hair follicles of the cashmere and angora goat

Hair fibre represents an important biological process to many feral and domesticated animals, both for environmental protection and as an aid to thermoregulation. Mohair which is the fine fibre produced by secondary hair follicles of the Angora goat grows essentially independent of season, with typical growth rates of 0.5-1 .0mm/day and annual yields typically 2-3kg. In contrast, down production from secondary hair follicles of double coated goats, classified as cashmere, is dependent on season. Fibre grows from around the summer to the winter solstice or later, with growth rates in this period of 0.3-0.7mm/day and annual yields maximally 600g but typically less than 100g. Questions arise as to how the seasonal stimuli affect fibre growth, and what determines the differences in fibre production between the two genotypes at the follicle level.In the work described here, based on thein vitroisolation and culture technique developed for the Angora and Cashmere goats by Ibraheemet al(1993, 1992 repectively) we have compared fibre volume producedin vivoandin vitro, examined the DNA concentration and protein depositional capacities of mohair and cashmere secondary follicles. In addition the effects of the hormones prolactin and melatonin as mediators of photoperiodin vivo, onin vitroprotein deposition in mohair and cashmere secondary hair follicles are also examined.

角質増殖型手・足白せん，生毛部白せんに対するＴｅｒｂｉｎａｆｉｎｅとＧｒｉｓｅｏｆｕｌｖｉｎとの二重盲検比較試験

新規経口抗真菌剤テルビナフィン125mg錠(以下TBF)の1日1回投与によるA群: 角質増殖型手·足白癬およびB群: 生毛部白癬に対する有効性と安全性を検討するため, 全国35施設にてグリセオフルビン(以下GRF)を対照薬とした二重盲検試験を実施した。総症例数は, A群が109例(TBF群: 55例, GRF群: 54例), B群が107例(TBF群: 54例, GRF群: 53例)であり, 本試験は実践的な試験との立場からintent-to-treatに基づき, 全例を対象として解析を行った。最終真菌学的効果判定の菌陰性化率は, A群ではTBF群: 80.0%, GRF群: 70.4%, B群ではTBF群: 66.7%, GRF群: 64.2%であった。皮膚症状判定の改善率は, A群ではTBF群: 74.5%, GRF群: 68.5%, B群ではTBF群: 77.8%, GRF群: 79.2%であった。総合効果判定の有効率は, A群ではTBF群: 78.2%, GRF群: 70.4%, B群ではTBF群: 72.2%, GRF群: 73.6%であった。安全性判定の「安全である」は, TBF群: 85.3%, GRF群: 76.6%であった。有用性判定の有用率は, A群ではTBF群: 70.9%, GRF群: 64.8%, B群ではTBF群: 70.4%, GRF群: 67.9%であった。以上, 有用以上での同等性について検討した結果A群において両薬剤が同等であることが検証された。従って, 角質増殖型手·足白癬に対してTBFはGRFと同等の有用性を持つ優れた薬剤と考えられた。またB群においては統計学的には同等性は証明されなかったものの, 有用率ではTBF群がやや勝っており, 生毛部白癬(広範囲)に対して臨床的にはほぼ同様の有用性を有するものと考えられた。

Histopathology of cutaneous changes in drug-induced coma.

Present knowledge of the histopathology of cutaneous changes seen in drug-induced coma is very incomplete: Only 1 of the 11 papers on this subject mentions follicular or sebaceous gland damage, with very little attention focused on vascular changes. We made a careful study of serial sections from eight cutaneous biopsy specimens from seven patients who suffered drug-induced coma with the following findings: (a) The secretory portion of the eccrine sweat coil is the epithelium most susceptible to necrosis. It is followed by, ex aequo, eccrine sweat duct, hair follicle, and sebaceous gland, and, lastly, the epidermis. (b) In the eccrine sweat duct, the outer root sheath of the hair follicle, and the epidermis, necrosis does not usually appear first in the outermost (basal cell) layer. (c) Necrosis of the outer root sheath of the telogen "club" follicle is usually more advanced than that of the secondary hair germ, and, at times, a spared anagen bulb can be seen in closest proximity. (d) Vascular changes correlate proportionately with epidermal damage and consist of a largely neutrophilic inflammatory infiltrate and blood vessel wall damage, mainly involving arterioles. Our findings contradict the widely accepted hypothesis that pressure is the main cause of the cutaneous changes in drug-induced coma.

Rate of growth and timing of growth and moulting of secondary fibre in Siberian and Icelandic X Feral goats fed high and low levels of dietary protein

The weight of secondary fibre (including fibre ˂18µ diameter (cashmere)) produced by goats differs greatly between genotypes. The reasons for such differences are unknown but may include differences in rate of growth, duration of the period of growth, the number of secondary hair follicles and fibre diameter.Studies of the effect of dietary protein level on secondary fibre production have so far indicated that there is little potential for nutritional manipulation of fibre yield. However, these studies have been confined to breeds which have relatively low yields of fibre.

Quantum hair on black holes

A black hole may carry quantum numbers that are not associated with massless gauge fields, contrary to the spirit of the “no-hair” theorems. We describe in detail two different types of black-hole hair that decay exponentially at long range. The first type is associated with discrete gauge charge and the screening is due to the Higgs mechanism. The second type is associated with color magnetic charge, and the screening is due to color confinement. In both cases, we perform semiclassical calculations of the effect of the hair on local observables outside the horizon, and on black-hole thermodynamics. These effects are generated by virtual cosmic strings, or virtual electric flux tubes, that sweep around the event horizon. The effects of discrete gauge charge are nonperturbative in ħ, but the effects of color magnetic charge become ħ-independent in a suitable limit. We present an alternative treatment of discrete gauge charge using dual variables, and examine the possibility of black-hole hair associated with discrete global symmetry. We draw the distinction between primary hair, which endows a black hole with new quantum numbers, and secondary hair, which does not, and we point out some varieties of secondary hair that occur in the standard model of particle physics.

Investigation of germinative cells in generating and renewed anagen hair apparatus in mice using anti-bromodeoxyuridine monoclonal antibody

To elucidate the cell kinetics in generating and renewed anagen hair apparatus in mice, S-phase cells in dorsal skin of new-born and 14 to 25-day-old mice were labeled with bromodeoxyuridine (BrdU) and stained immunohistochemically using anti-BrdU monoclonal antibody. In primary hair germ, lower and outer cells were positively stained. In hair peg, the positive cells were divided into upper and lower portions. In bulbous hair peg, the lower positive cells gathered at the suprapapillary area, whereas the upper positive cells were located in the outer part of the hair apparatus. The latter positive cells were further divided in the middle and upper parts of the epithelial cord. The upper cells were going to form a sebaceous gland. From the suprapapillary group of germinative cells, hair cortex through the innermost cell layer of the outer root sheath were considered to be produced. The positive cells of the outer middle group may be important for elongation of hair apparatus and produce outer root sheath cells. At the end of anagen phase, first the suprapapillary cells became negative and then the outer root sheath cells became negative. BrdU-positive cells reappeared at the bottom of telogen hair apparatus and formed a secondary hair germ. Then, a similar cell kinetics was repeated in the renewed anagen hair apparatus. The germinative cells were separated into a few groups during the generation and cyclic changes of hair apparatus. Each cell group formed the individual part of the hair apparatus in a coordinate fashion, resulting in dynamic changes of the hair apparatus.

Fibre growth cycles of cashmere-bearing, reproducing does in Southern Hawkes Bay, New Zealand, over a 30-month period

Abstract Fibre growth was measured in reproducing, cashmere-bearing does by sampling fibre and skin monthly from a mid-side position to give length of both cashmere and guard hair, hair follicle activity, and rate of fibre regrowth following shaving. New cashmere was first detected in the fleece of individual goats in January, February, or March and new guard hair in September, October, or November. By June each year, average cashmere staple length was close to maximum. Cashmere staple length was 54, 44, and 43 mm in June 1986 1987, and 1988, respectively. Average staple guard hair length reached a maximum of c. 45 mm each year and was never less than 24 mm because of the overlap of guard hair cycles. Growth rates were greatest for cashmere from February to May and for guard hair from December to April. Secondary (cashmere-producing) hair follicles grew short (0.6-2.3 mm) fibres during spring when mean secondary follicle activity reached 30%. Cashmere growth started around December–January, with mean secondary follicle activity increasing rapidly to reach more than 90% by February where it remained until late May. Activity of primary (guard hair-producing) hair follicles increased rapidly from October and remained high until late March. Cashmere growth was close to completion by June and histological findings indicated that shedding was beginning in August. Consequently optimal cashmere returns should be achievable by shearing in June–July although winter shearing may create management difficulties.

Hair anatomy for the clinician

The rational evaluation of hair disorders requires familiarity with follicular anatomy. Hair structure can be easily examined by studying clipped hair shafts, entire hairs gently pulled or forcibly plucked from the scalp, and scalp biopsies (sectioned vertically or transversely). Anatomic features will be different depending on whether a given hair is in the anagen, catagen, or telogen phase. Follicle size will also vary, from the minute vellus hair to the long, thick terminal hair. Each follicle can be divided into distinct regions--bulb, suprabulbar zone, isthmus, and infundibulum. Activity growing (anagen) hairs are characterized by a hair matrix surrounding a dermal papilla; inner and outer root sheaths are present and well developed. A catagen hair can be identified by its markedly thickened vitreous layer and fibrous root sheath, which surrounds an epithelial column; above this column, the presumptive club forms. A telogen hair is distinguished by its fully keratinized club, which is surrounded by an epithelial sac. Below this lies the secondary hair germ and condensed dermal papilla, waiting for the mysterious signal that initiates a new life cycle.

Secondary follicle development in Australian cashmere goats

Development of secondary hair follicles was studied in three sets of twin goat kids, from two weeks to fourteen months of age, in order to determine the age at which full cashmere production potential has been reached. Kids achieved maximum secondary follicle development (determined from monthly skin secondary to primary follicle (S:P) ratio measurements) at about 20 weeks after birth, at which time cashmere percentage, determined from fibre samples, was found to be a good approximation of the proportion of secondary follicles of these animals born in October (spring). No difference in S:P ratio or rate of secondary follicle maturity was found between male and female kids. It is proposed that S:P ratio determinations on skin biopsy samples would not be significantly more useful than fibre diameter measurements taken at the same time. If S:P ratio measurements are to be made, samples should be taken during the summer months when the follicles are active, in order to avoid difficulties encountered with such measurements during the resting or shedding stage. Fibre diameter was greatest during summer, narrowing again in winter immediately before shedding. It is suggested that fibre samples taken between the ages of 20 and 40 weeks of age may be used to select animals for production purposes, at least for kids born in spring.

Alopecia syphilitica, a simulator of alopecia areata: histopathology and differential diagnosis

Alopecia syphilitica (AS) may be "moth-eaten" or diffuse, clinically, and be confused with alopecia areata (AA) or other alopecias. The English language literature contains scant information regarding the histopathology of AS, and the resemblance between AS and AA has not been given adequate recognition. We report the histopathological findings of AS from nine patients with secondary syphilis and acute hair loss. The alopecia was moth-eaten in four patients and diffuse, but slightly moth-eaten, in five. Microscopically, the dermoepidermal interface was not involved. The numbers of hair follicles were diminished, with increased numbers of catagens and telogens. Lymphocytic infiltration was present around the hair bulbs and fibrous tracts in eight cases. Plasma cells were present in four biopsies. Other less common findings included lymphocytes in the isthmus, parabulbal lymphoid aggregates, and granulomatous infiltrate in the upper dermis. The findings, save for the follicular changes, resembled those of macular/maculopapular syphilides outside the scalp. With the follicular changes, the overall patterns resembled AA closely. The modified Steiner stain did not reveal spirochetes in any of our cases and failed to differentiate between AS and AA. Comparing the AS cases to 13 cases of AA, we found only a few differentiating features. The presence of peribulbal eosinophils strongly suggests AA. Without peribulbal eosinophils, the presence of plasma cells, abundant lymphocytes in the isthmus, or parabulbal lymphoid aggregates suggests AS.

The responses of primary and secondary sensory hair cells in the squid statocyst to mechanical stimulation

Intracellular recordings were obtained from primary and secondary sensory hair cells in the anterior transverse crista segment of the squid (Alloteuthis subulata) statocyst during imposed displacements of the overlying cupula. The secondary sensory hair cells were depolarized by ventral movements of the cupula and hyperpolarized by dorsal cupula movements. The displacement/response curve was asymmetric around the zero position and sigmoidal in shape, similar to that already described for vertebrate hair cells. The cells are estimated to have a sensitivity of at least 0.5 mV per degree angle of cilia displacement. The responses showed pronounced adaptation and could be blocked by bath applied alcohols, such as heptanol or octanol, or by high concentrations of aminoglycosides.

Electrical coupling between secondary hair cells in the statocyst of the squid Alloteuthis subulata

The cephalopod angular acceleration receptor system has sensory response characteristics similar to those of the vertebrate semicircular canal system and, unusual for an invertebrate, contains secondary receptor hair cells. The experiments reported use intracellular recordings from pairs of hair cells to show that at least one subset of the hair cells is electrically coupled along the entire length of the crista section. The coupling can be reduced by application ofheptanol or octanol. Intracellular injection of H + ions into a hair cell reduces the coupling of cells on the opposite site of the injected hair cell but does not abolish it completely. It is proposed that the coupling is likely to result in an improvement in the signal-to-noise ratio of the receptor system, a reduction in overall frequency response, but an increase in the low frequency sensitivity.

Secondary hair cells and afferent neurones of the squid statocyst receive both inhibitory and excitatory efferent inputs

Intracellular recordings were obtained from the hair cells and afferent neurones of the angular acceleration receptor system of the statocyst of the squid,Alloteuthis subulata. Electrical stimulation of the efferent fibres in the crista nerve (minor) evoked responses in all of the secondary hair cells recorded from (n=211). 48% of the secondary air cells responded with a small depolarization, 15% with a hyperpolarization, and 37% with a depolarization followed by a hyperpolarization. The depolarizations and hyperpolarizations had mean stimulus to response delays of 6.7 ms and 24 ms, and reversal potentials of about −1 mV and −64 mV, respectively. Both types of potential increased in amplitude, up to a point, when the stimulus shock was increased and facilitation and/or summation effects could be obtained by applying multiple shocks. These data, together with the fact that both responses could be blocked by bath application of cobalt or cadmium, indicate that the secondary hair cells receive both inhibitory and excitatory efferent inputs and that these are probably mediated via chemical synapses. No efferent responses were seen in the primary hair cells but both depolarizing and hyperpolarizing efferent responses were obtained from the afferent neurones.