Medullary trichomalacia in 6 German shepherd dogs

Medullary trichomalacia is the name proposed for a hair shaft abnormality that was recognized in 6 German shepherd dogs. Affected dogs had multifocal areas of broken hairs, especially on the dorsolateral trunk. Microscopic examination of hair shafts revealed focal areas of loss of architecture, swelling, and apparent softening of the medulla, followed by longitudinal (length-wise) splitting and breakage of the hair shaft. No cause could be found. Affected dogs were otherwise healthy, and apparent spontaneous recovery was the usual outcome. Relapses may occur.     

Oestrogen receptor evaluation in Pomeranian dogs with hair cycle arrest (alopecia X) on melatonin supplementation

The role of oestrogen receptors in dogs with hair cycle arrest (alopecia X) was investigated by immunohistochemistry. The purpose of this study was to determine if hair regrowth in dogs with hair cycle arrest treated with melatonin was associated with a decrease in follicular oestrogen receptors. Fifteen Pomeranians (excluding intact females) with hair cycle arrest were enrolled. Two biopsies were obtained from alopecic areas of the trunk before and after 3 months on melatonin. Haematoxylin and eosin-stained tissues were examined and oestrogen receptor-alpha was demonstrated immunohistochemically. Common histopathological findings included hyperkeratosis, follicular keratosis, excessive tricholemmal keratinization (flame follicles), thin epidermis, few small anagen bulbs, epidermal pigmentation and melanin aggregates within follicular keratin. Melanin aggregates within basal cells and hair were an occasional finding. After 3 months, 40% (six) dogs had mild to moderate hair regrowth. Biopsies from six dogs showed histological evidence of an increase in anagen hairs and eight dogs had a decrease in epidermal pigmentation. Moderate to marked staining intensity of oestrogen receptor-alpha was noted in all sebaceous gland basal cells, all small hair bulbs and follicular epithelium of telogen hairs. There was no oestrogen receptor-alpha staining of nuclei within the epidermis, apocrine glands or dermal fibroblasts. Large anagen hair bulbs had minimal to no oestrogen receptor staining. Hair regrowth was not associated with a change in oestrogen receptor-alpha staining.     

The effect of body region on the canine hair cycle as defined by unit area trichogram

The impact of anatomic location on trichogram analysis of the hair cycle phases was evaluated in 15 clinically normal dogs. The purposes of this study were to determine if the number of hairs in anagen and telogen vary among anatomic sites within a dog and to see whether there is an optimal region to sample hairs for canine trichogram evaluation of the hair cycle phases. In each dog eight sites were sampled. Four (26.7%) of the 15 dogs had no significant differences in the number of hairs in anagen and telogen among the eight body sites examined. Nine (81.8%) of the remaining 11 dogs had only one site that revealed significant differences in the number of hairs in anagen or telogen. In seven (77.8%) of these dogs only the anagen differed significantly, and in two (22.2%) dogs both phases differed significantly. Two (18.2%) dogs revealed two sites with significant differences in the number of hairs in anagen. The number of hairs in anagen and telogen in the shoulder area did not vary significantly in any of the dogs. This observation, coupled with the ease of sampling at this site, indicates that the shoulder is the site of choice when studying variations in ratios of hair cycle phases using unit area trichogram. Our results also suggest that numbers of telogen and anagen hairs from body regions with different hair shaft lengths do not vary significantly, and the occasional inconsistent results noted at some body sites might be due to sample collection technique.     

Seasonal Moulting in Adult Male Raccoon Dog (Nyctereutes procyonoides)

Abstract

Seasonal moulting was studied by quantitative histology and external observations in adult male raccoon dogs. Moulting of the underfur hairs is characterized by a heavy loss of old winter hair in spring and an intensive growth of new winter hair in autumn. Only few mature and growing underfur hairs were found in the hair cover in summer. The new intermediate and large guard hairs started to develop in April and May. All the new guard hairs had developed by the end of June. About 7 and 3.5 months were needed for the growth of new winter guard and underfur hairs respectively. At the end of November the winter fur was mature. The bundles with an intermediate guard hair contained more underfur hairs than the bundles with a large guard hair in the mature winter fur. The thickness of dermis and the grade of skin colour peaked in the autumn moult, indicating a close relation to the activity of hair follicles.     

A hair abnormality in Abyssinian cats

An abnormality of the hair shaft of the whiskers and guard hairs of Abyssinian cats, consisting of an onion-shaped swelling, usually situated at the tip of the hair but occasionally at other sites along the hair shaft, is reported. Where the abnormality occurs in the guard hairs it imparts a rough, brittle and lustreless appearance to the coat. Microscopically the epidermis, dermis and hair follicles and appendages appear normal. The condition has been seen in two Abyssinian cats in Denmark and one in Australia.     

毛囊干细胞的分离方法及其应用

毛囊干细胞是皮肤组织工程理想的种子细胞,分离纯化是其研究的基础手段。毛囊干细胞能分化成毛囊、皮脂腺、表皮,在组织维持与更新及某些临床疾病的治疗中均起到重要的作用。作者介绍了近年来毛囊干细胞几种常用的分离纯化方法,包括组织块法和酶消化法等,为进一步研究毛囊干细胞的特性和应用提供参考。     

The effects of thyroid hormones on the skin of beagle dogs

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.     

Distribution of acid and alkaline phosphatases in canine skin.

Azo dye methods were used to determine the distribution of acid phosphatase (ACP) and alkaline phosphatase (ALP) in the skin of 25 Beagle dogs. ALP activity was found in dermal papillae of hair follicles regardless of their state of activity, in Huxley's layer of the inner root sheath of anagen stages, in myoepithelial cells of apocrine sweat glands, in germinative cells of sebaceous glands, in vascular endothelium, and in mast cells. The ACP activity was found in the epidermis, outer and inner root sheaths, keratogenous zone, hair cuticle and medulla, duct of sebaceous gland, and sebum. The results indicate that ACP and ALP are distinctive enzymes serving different biologic functions. The principal role of ALP in the skin appears to be dephosphorylation for adsorption and transport of chemical substances necessary for growth and maintainence of the pilary system and glandular adnexa. The ACP appears to be primarily involved in the breakdown of phospholipids and in necrobiosis of keratinocytes.     

Measuring cortisol in hair and saliva from dogs: coat color and pigment differences

Cortisol concentrations are frequently measured from a variety of sources including blood, saliva, urine, and feces to quantify stress in dogs. However, a need still exists for less intrusive collection methods in domestic animals and for more efficient means of measuring basal cortisol. The objectives of the present study were to minimize restraint for saliva sampling, to validate hair for basal cortisol measurement in dogs, and to determine concentrations of cortisol within the hair shaft and in relation to hair color. Using food luring, 79% of dogs required no restraint for saliva collection. Salivary and hair cortisol concentrations were positively correlated (P = 0.001), thus validating hair as a medium for basal cortisol quantification. Black dogs had less cortisol than nonblack dogs (P = 0.039) in hair, but not saliva. Across dogs, the average amount of cortisol did not differ between proximal and distal hair sections (P = 0.348). However, for 7 of the 9 dogs, more cortisol was present in the distal portions of the hair. We observed a difference in cortisol concentrations among hairs of different colors from individual dogs (P = 0.001). From the same 7 × 7 cm ischiatic patch from the same dog, black (eumelanin) hairs were consistently lower in cortisol than yellow (pheomelanin) hairs, and cortisol concentrations of agouti hairs were intermediate. This is the first evidence that hair of different colors might sequester cortisol differently.     

Congenital follicular dysplasia in five related coatimundis (Nasua nasua)

We report a congenital follicular dysplasia in five coatis from four different litters of the same parents born between 1996 and 2001. These coatis were born apparently alopecic with the entire body covered by very short dark hairs, with secondary lichenification of the skin, crusting and scaling. The main histopathological feature consisted of premature cornification of the cortical cells of the hair shaft. Cells were already fully cornified below the Adamson's fringe, leading to a disorganized, fragmented and constricted hair shaft. Based on the history of the animals and the nature of the lesions, a genetic defect in hair shaft keratinization was suspected.     

Hair cycle in dogs with different hair types in a tropical region of Brazil

Hair cycle activity has been extensively studied in humans, sheep and laboratory animals, but there is a lack of information in dogs. Besides varying according to species, breed, sex and general health, hair growth is mainly affected by climatic variations. The aim of the study was to evaluate the follicle activity in three breeds of dogs with different hair types, in the city of Viçosa, Minas Gerais (latitude 20°45′S), Brazil. Twenty‐one male dogs of boxer, labrador and schnauzer breeds were trichographically analysed monthly over 12 consecutive months. Hair percentage of telogen and anagen hairs at the different stages of the hair cycle in boxers and labradors was not significantly different, but both differed from the schnauzers. A significant correlation between hair follicle cycle and environmental temperature and photoperiod was noted in the boxers and labradors. In these breeds, a larger number of telogen hairs were observed during the hottest months of the year, and an increase in anagen hairs during the coldest months. The mean percentage of telogen hairs was 93, 90 and 55.3% for boxer, labrador and schnauzer, respectively.     

Histopathologic features of canine distichiasis

Objective To describe the histologic features of canine distichiasis using excised tarsoconjunctival specimens that included roots of distichiatic cilia. Procedures The study group included 21 strips of cilia‐bearing tarsoconjunctiva resected from 20 dogs with distichiasis. Eyelid tissue specimens were also collected from 11 euthanized dogs without distichiasis to serve as controls. All flat mount preparations were processed for histologic examination, and serial sections were stained with hematoxylin‐eosin (H&E). A total of 157 slides were examined for the study group to describe the follicles and path of the distichiatic hairs and determine their potential connection with the tarsal glands. A total of 82 slides were examined for the control group. Results In 19 of the 20 dogs with distichiasis, serial sections of the specimens identified anatomic segments of hair follicles located abnormally in the eyelid tarsus and associated with the aberrant cilia. They appeared as hair bulbs adjacent to tarsal glands, middle portions of hair follicles located between sebaceous lobules, and single or multiple hair shafts present within the sebaceous duct. The tarsal glands in the cilia‐bearing tarsoconjunctiva were not different from those of the controls, in which no distichiatic hair bulbs or shafts were observed. Conclusions These results demonstrate that adventitious cilia are not associated with histologic changes of the tarsal glands, and appear to arise from ectopic hair follicles present in the tarsus. Canine distichiasis may result from anomalous regulation of morphogenesis of hair follicles in the mesenchymal tissue of the tarsal plate.     

Notoedric mange in free-ranging masked palm civets (Paguma larvata) in Japan

Fifty-one masked palm civets (Paguma larvata) were trapped as part of a nuisance wildlife control programme between July 2001 and August 2002 in Fujisawa City, Kanagawa Prefecture, Japan. Eleven civets had characteristic mange lesions with marked alopecia and crusts, caused by the burrowing epidermal mite Notoedres cati. The diagnosis was confirmed by histology and examination of mites obtained from skin scrapings of affected civets. Histopathology of lesions demonstrated moderate hyperplastic epidermis, parakeratosis and acanthosis. Occasionally microvascular angiogenesis was observed in the epidermis. Tunnels were excavated in the hair follicles, reaching the hair roots. The tunnels were located between the hair shaft and the inner root sheath. Female mites, eggs and nymphs were demonstrated in their tunnels using scanning electron microscopy.     

基于单细胞转录组测序技术对鄂尔多斯细毛羊次级毛囊形态发生诱导期的研究

【目的】试验旨在解析鄂尔多斯细毛羊胚胎期次级毛囊诱导期形态发生过程中主要细胞类型的分子特征和分化过程。【方法】对采集的3只鄂尔多斯细毛羊(胎龄87 d)体侧部(肩胛骨后缘处)的皮肤样本进行HE染色,鉴定毛囊的发育时期;部分皮肤样本经过混样后进行单细胞转录组测序(scRNA-Seq),应用t-分布随机近邻嵌入(tSNE)分析细胞簇,分别使用胶原Ⅰ型α1链(Col1a1)和角蛋白15(Krt15)鉴定真皮谱系细胞和表皮谱系细胞,并使用皮肤组织不同细胞的标记基因进行细胞类型分析;对测序数据进行拟时序分析,探究其分化过程中差异基因的表达;通过GO功能富集分析进一步验证基因的功能。【结果】HE染色结果发现,鄂尔多斯细毛羊在胎龄87 d处于次级毛囊诱导期。通过scRNA-Seq在胎龄87 d的细毛羊体侧部皮肤细胞样品中获得10 603个细胞和18 704个基因的scRNA-Seq数据可用于下游分析。tSNE分析发现,皮肤组织中共有15个细胞簇;Col1a1和Krt15标记基因鉴定表明,真皮细胞和表皮细胞具有高度异质性。拟时序分析构建毛囊形态发生过程中真皮/表皮细胞谱系细胞的分化轨迹和基因动态表达图...     

毛囊的周期性变化和分子调控及其在绒山羊上的研究进展

毛囊是一个形态和结构较为复杂的皮肤附属器官,它控制着毛发的生长,具有自我更新和周期性生长的特点。毛囊的周期性变化依靠毛囊上皮细胞和真皮间充质细胞的相互作用,先是毛囊长出毛干为生长期,接下来是凋亡驱动的退行期,然后进入休止期。其变化过程是一系列信号分子相互作用形成的,包括启动信号、维持毛囊生长的信号及抑制毛囊生长的信号等。绒山羊初级毛囊和次级毛囊在出生后也表现周期性变化,次级毛囊由于光周期的影响而呈很强的季节性的周期变化,而初级毛囊则变化不明显。山羊绒是绒山羊次级毛囊的衍生物,次级毛囊的生长发育直接影响山羊绒的产量和品质。因此,研究皮肤毛囊周期性变化的规律及它们的分子调控机理不仅可揭示毛囊的发育规律而且对绒山羊的育种具有重要指导意义。     

Histopathologic features of the skin of hairless newborn pigs with goiter.

The skin of 15 hairless newborn pigs with parenchymatous goiter was studied histopathologically. Most of the lesions were in the hair follicles; follicles were scarce and reduced in size, contained slender hairs, and revealed a shortage of penetration into the hypodermis. Hair follicles in the immature stages, hair pegs, and germs also were recognized, with the thin epidermis lacking in keratinization. It was felt that these changes resulted from a retardation of cellular differentiation of the germinal layer. In view of these findings, skin lesions were regarded as hypoplasia of hair.     

Hair coat characteristics and postweaning growth of Hereford and Angus cattle

Mid-rib hair coat samples (n = 577) were obtained from 9- to 10-mo-old Hereford and Angus bulls and heifers to examine diet and breed differences in hair coat characteristics and their relationship to 168-d postweaning gain. Each sample was cleaned and subdivided into guard hairs and undercoat. Dependent variables included the number, weight, length, diameter and percentage of medullation of guard hairs and undercoat. Sources of variation included breed, sire nested within breed, year (1965 or 1966), sex of calf, diet fed during the postweaning gain test (2 parts rolled grain:1 part chopped hay vs all chopped hay) and the linear regression on age of calf as a covariate. Factor analysis was used to transform the 10 hair coat variables into a set of four factors that accounted for 71% of the total variance of the original variables. Angus cattle tended to have shorter, less medullated coats (Factor 1), shorter, larger diameter undercoat hairs and guard hairs with less medullation than Herefords. Sire within breed differences existed for weight, length, and diameter of both types of hairs and all four factors. Compared with the medium-energy-diet, the high-energy diet reduced hair weight per unit of surface area, undercoat number and guard hair medullation. Undercoat density (Factor 3) was reduced by the higher-energy diet (P less than .001), whereas guard hair density (Factor 2) was not changed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Black Hair Follicular Dysplasia in Black and White Saluki Dogs: Differentiation from Color Mutant Alopecia in the Doberman Pinscher by Microscopic Examination of Hairs

Abstract— Four black and white female Saluki puppies developed variably severe hypotrichosis in black haired areas. Histologically, follicles in black haired areas were dilated with keratin and clumps of melanin pigment, and were irregularly shaped. Melanin pigment was also clumped in hair shafts, basal layer of epidermis, epithelial cells of hair bulbs and macrophages around follicles, especially at the base. White haired areas were normal grossly and histologically. Light microscopic examination of dehydrated and cleared primary black hair shafts from one Saluki with black hair follicular dysplasia and primary blue hair shafts from two blue Doberman pinschers with color mutant alopecia revealed that the blue Dobermans had many more visible macromelanosomes than the Saluki. On scanning electron microscopy, cuticular abnormalities were identified in some white and all black hairs from the Saluki. Several black hairs had shallow, oval defects in the superficial cortex. Blue hairs from one Doberman had similar, but more extensive changes. Résumé— Quatre chiots femelles Saluki noirs et blancs ont développé une hypotrichose plus ou moins étendue des zones de poils noirs. Sur le plan histologique, les follicules pileux des zones de poils noirs étalent dilatés, de forme irrégulière et obstrué par des bouchons de keratine et de mélanine. Des pigments mélaniques en motte sont aussi retrouvés dans la lumière des poits, les cellules basales de l'epiderme, les cellules épithéliales de bulbes pileux et les macrophages entourant les follicules pileux. Les zones de poils blancs étaient normales, tant macroscopiquement que micrioscopiquement. L'examen en microscopie optique de poils noirs primaires deshydratés et éclaircis provenant d'un de ces Saluki et de deux Doberman atteints d'alopécle des mutants de couleur a révélé un beaucoup plus grand nombre de macromélanosomes chez les Dobermans que chez le Saluki. En microscopie électronique à balayage des anomalies de la cuticule ont été observées sur quelques poils blancs et tous les poils noirs des Salukis. Plusieurs poils noirs présentaiert des déformations ovales peu profondes de la cuticule. Les poils bleus des Dobermans présentaient le même type de déformation, mais de façon plus étendue. Zusammenfassung— Vier schwarz-weiße weibliche Salukiwelpen entwickelten abwechselnd eine schwere Hypotrichose in den schwarzgefärbten Fellbezirken. Im histologischen Bild waren die Follikel in den schwarzgefärbten Fellbezirken durch Keratin und Melaninpigmentklumpen dilatiert sowie unregelmäßig geformt. Das Melaninpigment war in den Haarschäften, in der Basalzellschicht der Epidermis, den Epitheizellen der Haarbulbi und den Makrophagen um die Follikel, besonders an der Basis, ebenfalls zusammengekiumpt. Die weißen Fellbezirke waren makroskopisch und histologisch unverändert. Die lichtmikroskopische Untersuchung von dehydrierten und aufgehellten Schäften schwarzer Primärhaare eines Salukis mit follikulärer Dysplasie schwarzer Haare und der Untersuchung der Haarschäfte blauer Primärhaare zweier blauer Dobermannhunde mit Farbmutantenalopezie zeigte, daß die blauen Dobermänner viel mehr sichtbare Makromelanosomen als der Saluki aufwiesen. Bei der Untersuchung mit dem Elektronenmikroskop konnten Abnormitäten der Kutikula bei einigen weißen und bei alien schwarzen Haaren des Salukis festgestellt werden. Einige der schwarzen Haare zeigten flache, ovale Defekte in der oberflächlichen Rinde. Blaue Haare eines Dobermanns zeigten ähnliche, aber viel ausgedehntere Veränderungen. Resumen Cuatro cachorros hembra de Saluki negro y bianco se desarrollaron con variable gravedad hipotricosis en areas de pelo negro. Histológicamente los folículos de las zonas de pelo negro fueron dilatados con keratina y grupos de pigmento de melanina, y fueron irregularmente formados. El pigmento de melanina también fue encontrado irregularmente en el cuerpo del pelo, capa basal de la epidermis, células epiteliales de los bulbos pilosos y macrófagos alredador de los folículos, especialmente en la base. Las areas de pelo bianco eran normales en cuanto tanto macroscopicamente como histológicamente. El examen microscópico del cuerpo de pelos negros deshidratados y aclarados de un saluki con displasia folicular de pelo negro y cuerpo de pelo azul primario de dos Doberman pinschers con alopecia de color mutante, reveló que los Dobermans azules tenían muchos mas macromelanosomas visibles que el Saluki. Al microscopio electrónico se identificaron abnormalidades cuticubres en algunas pelos blancos y todos los negros en el Saluki. Varios pelos negros tenían pequenos defectos ovales en la corteza superficial. Los pelos azules de uno de los Doberman presentaban cambios similares pero más extensos.     

Immunohistochemical analysis of cytokeratin expression in dog skin

The expression of cytokeratins and involucrin was analyzed to identify the skin cells which compose the epidermis of dogs. The distribution of cytokeratins and involucrin in normal dog skin was immunohistochemically examined with 27 commercial monoclonal antibodies for human use. Antibodies, No.4. OV-TL12/13, 35betaH11, 4.1.18, CAM5.2, NCL5D3, Ks.13.1, Ks.18.04, Ks.19.1, 170.2.]4 and Ks.20.8 stained hair follicles and/or the sweat gland duct, but not the epidermis. Antibodies, 34betaB4, AE3, 34betaE12. LP34, RCK102, MNF116, AE1, KLI, DE-K10 and DE-K13 reacted with every layer of the epidermis, hair follicles and the sweat gland duct. These results were similar to those reported in the human skin. No positive staining, however, could be detected in the epidermis, hair follicles and the sweat gland duct with commercial antibodies, 6B10, Ks.7.18, Mu146-uc, E3, RCK108 and involucrin. Therefore, immunohistochemical investigation with these commercial antibodies developed for human skin examination might be available for investigating the origin of skin tumors in dogs.     

Black hair follicular dysplasia in Large Münsterländer dogs: clinical, histological and ultrastructural features

Four Large Münsterländer cross‐bred dogs affected with black hair follicular dysplasia (BHFD) and one unaffected control littermate were observed, and skin was sampled weekly over the first 19 weeks of life. Affected dogs were born with silvery grey hair, a consequence of melanin clumping in the hair shafts. Hair bulb melanocytes were densely pigmented, and contained abundant stage IV melanosomes but adjacent matrix keratinocytes lacked melanosomes. Melanin clumping was not prominent in epidermal melanocytes in the haired skin but occurred in the foot pads. Follicular changes progressed from bulbar clumping, clumping in the isthmus/infundibulum and finally to dysplastic hair shafts. Alopecia developed progressively in pigmented areas. Silver‐grey hair, melanin clumping, accumulation of stage IV melanosomes within melanocytes and insufficient melanin transfer to adjacent keratinocytes are also classic features of human Griscelli syndrome. The underlying cause in Griscelli syndrome is a defect of melanocytic intracellular transport proteins leading to inadequate and disorganized melanosome transfer to keratinocytes with resultant melanin clumping. In view of the correlation in the phenotype, histology and ultrastructure between both disorders, a defect in intracellular melanosome transport is postulated as the pathogenic mechanism in BHFD.