A Method for Determining the Activity State of Hair Follicles

Nixon, A. J.

doi:10.3109/10520299309105637

Cited by 77 publications

(58 citation statements)

References 9 publications

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“…All skin samples were fixed in 10% buffered formalin and processed by dehydration in increasing concentrations of ethanol and D-limonene (Histosolve; HD Scientific, Wetheril Park, New South Wales, Australia). Explants were embedded in paraffin wax in transverse orientation, and 7 mm serial sections were cut and stained using a modified SACPIC staining protocol (Nixon, 1993).…”

Section: Methodsmentioning

confidence: 99%

The effects of short-term manipulation of thyroid hormone status coinciding with primary wool follicle development on fleece characteristics in Merino sheep

McDowall

Edwards

Hynd

2011

Animal

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Thyroidectomy surgery performed late in gestation results in perturbations in wool follicle development in foetal sheep, showing the importance of thyroid hormones for wool follicle development. The aim of this study was to determine the influence of transient manipulation of thyroid hormone status at a time corresponding with foetal primary wool follicle initiation. Pregnant Merino ewes (n 5 12 per treatment) were treated daily between gestational days 55 and 64 with control (vehicle), exogenous thyroxine (T4) or propylthiouracil (PTU), an inhibitor of T4 synthesis, and conversion to the active form of the thyroid hormone (triiodothyronine). There were no significant differences in birth weight, gestational lengths and birth coat scores of the resultant lambs. The total primary and secondary follicle densities were significantly lower in lambs exposed to exogenous T4 compared with other treatments (P , 0.05). However, the T4 group displayed a higher proportion of mature secondary follicles (reflected by increased mature secondary follicle densities and mature secondary/primary follicle ratios) than the other treatment groups (P , 0.05). The skin morphology of the lambs differed 12 months later, with the T4 group having significantly higher total follicle densities compared with the PTU group, largely attributed to increased mature and total secondary follicle densities. However, this increase in wool follicle densities did not translate to differences in the fleece yields and weight, fibre diameter, staple lengths or any other fibre parameters. This study showed that transient manipulation of thyroid hormone status during foetal primary follicle initiation does have long-term consequences on the morphology of wool follicles, in particular the maturity of secondary wool follicles.

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Section: Methodsmentioning

confidence: 99%

The effects of short-term manipulation of thyroid hormone status coinciding with primary wool follicle development on fleece characteristics in Merino sheep

McDowall

Edwards

Hynd

2011

Animal

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“…Transverse sections of 7 mm were cut with a rotary microtome and stained by using the Sacpic staining procedure, modified by Nixon (1993). This dyeing method reveals the follicular inner root sheath (IRS, which shows activities only in the anagen phase) and the cellular layer of the outer root sheath, which are the main histological structures for defining skin follicular activity.…”

Section: Methodsmentioning

confidence: 99%

Hair follicle characteristics and fibre production in South American camelids

Antonini

2010

Animal

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Hair follicle and fibre characteristics of Peruvian alpaca and llama and Bolivian llama were analysed in three experimental studies. The first experiment was designed to determine the age at which all the secondary follicles reach maturity, as well as to compare the skin follicular structure and activity among these different types of Peruvian camelids. It is concluded that the South American camelids investigated in this study gained a complete and mature skin follicle apparatus at an early age, and hence producers should practise an early first shearing. A second Peruvian experiment investigated comparative fibre cuticular structure on twenty Peruvian domestic camelids comprising huacaya, suri and llama (woolly) 'chacos' genotypes. The results showed that the number of cuticular scales per 100 mm fibre length proved to be strongly affected by both the fleece type and the fibre diameter. The suri fleece was clearly differentiated from those of both huacaya and llama by possessing the highest percentage of fibres with a number of scales less than eight, the lowest percentage of fibres with more than nine scales, along with the lowest percentage of fibres with a diameter of more than 35 mm. It is concluded that, with the exception of the scale height, the cuticular parameters investigated in this study can be utilised in textile fibre analyses for distinguishing among these three types of fleece, as well as in selection projects designed to produce homogeneous fibres from Peruvian domestic camelids. A further study was conducted to determine the age at which the hair follicles in Bolivian llamas reach maturity as well as for comparing the skin follicular structure and activity between the two distinct genotypes. Thirty-one llama kids were chosen. They were born between January and April 1998 and were of different sex and of 'Q'aras' (or Carguera) or 'T'amphullis' type. Skin biopsies were taken from the right mid-costal region at 2, 4, 6, 8,10,12 and 14 months of age in order to monitor four follicular parameters. In this experiment, secondary to primary (S/P) data show that the Bolivian llama population analysed possessed a complete and mature skin follicle apparatus at birth that remained essentially constant throughout the investigation period. Due to the variation of these traits inside the same genetic population, the present results showed that T and Q types could only be subjective on the basis of S/P ratio.Keywords: alpaca, llama, skin hair follicle, fibre cuticular structure, post-natal follicle development Implication This paper aims to provide the latest information on the main fibre production parameters in domestic South American camelids. The research focuses on two characters: skin follicular structure, fibre cuticular cell and their distribution in alpaca and llama. In particular, the information is on the first few months of life of the animals in order to explain how fleece and skin change during the first year and when the fleeces are ready to be collected. New differential data on suri fibre de...

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“…Skin samples were fixed (10% buffered formalin; weight/volume), processed through graded alcohols, and embedded, epidermal surface uppermost, in paraffin wax. The skin was then serially sectioned (8 |Lim) in the transverse plane and stained with adapted Sacpic stain (Nixon, 1993). Primary and secondary follicle activities were assessed according to staining characteristics of the inner-root sheath (Nixon, 1993).…”

Section: Methodsmentioning

confidence: 99%

A note on defleecing of Angora and Spanish goats using Leucaena

Litherland

Yami²,

Sahlu³

et al. 1999

J. Anim. Feed Sci.

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Thirty Angora (16±2 kg) and 20 Spanish (19±2 kg) 8-month-old doelings, having not previously consumed Leucaena leucocephala, were used to determine effects of dietary inclusion of a moderate level of Leucaena on fleece shedding and subsequent fibre characteristics. A diet of 22.5% Leucaena leaf meal (0.17% mimosine in total diet dry matter) was consumed ad libitum for 8 days starting on November 13, with daily mimosine intake in the first 3 d averaging 56 mg/kg body weight. At d 10, fleece shedding was clearly visible in 17 of the 30 Angora doelings and in 9 of the 20 Spanish doelings. Doelings in which the visual shedding score was above 2 (5-point scale: 1 = no shedding and 5 = excessive shedding; mean of cashmere and guard shedding scores for Spanish doelings) on d 19 were categorized as exhibiting a shedding response to Leucaena. By d 35, six Angora and three Spanish doelings had completely shed fleece. Clean mohair growth rate in Angora doelings was lower (PO.05) for shedding vs nonshedding doelings on d 8 to 40 (0.29 vs 0.68 mg/ (cm 2 d* 1 )) but similar (P>0.10) between shedding groups on d 41 to 63 (1.51 vs 1.46 mg/(cm 2 d 1 )), although cashmere growth rate was not different (P>0.10) between shedding groups on either d 8 to 40 or d 41 to 63. Secondary follicle activity was lower (PO.05) on d 8 for shedding than for nonshedding Angora doelings (89 vs 99%), but activity on d 63 was similar (95 and 96%, respectively). Secondary follicle activity for Spanish does was similar between shedding groups on d 8 and 63 (P>0.10). In conclusion, feeding of Leucaena holds promise as a means of inducing fleece shedding in goats, apparently without marked subsequent effects on productivity. However, further research with higher dietary levels of mimosine is necessary.

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A Method for Determining the Activity State of Hair Follicles

Cited by 77 publications

References 9 publications

The effects of short-term manipulation of thyroid hormone status coinciding with primary wool follicle development on fleece characteristics in Merino sheep

The effects of short-term manipulation of thyroid hormone status coinciding with primary wool follicle development on fleece characteristics in Merino sheep

Hair follicle characteristics and fibre production in South American camelids

A note on defleecing of Angora and Spanish goats using Leucaena

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