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.     

The impact of body site, topical melatonin and brushing on hair regrowth after clipping normal Siberian Husky dogs

The aims of this study were to determine the impact of body site, vigorous brushing and topical melatonin treatment on hair regrowth after clipping normal dogs. Siberian Husky dogs were randomly assigned to three groups of eight dogs each. All dogs had the lumbosacral region and both lateral thighs clipped. The left thigh and lumbosacral area received no treatment and were compared in all 24 dogs. Eight dogs had the right thigh treated with 0.1% melatonin twice daily for 2 months, and hair regrowth was compared with the left thigh. Eight dogs had the right thigh brushed twice daily for 2 months, and hair regrowth was compared with the left thigh. Eight dogs had neither thigh treated. Hairs were plucked before and 2 months postclipping, and the proportion of hair growth from the original length was calculated and compared as described above. Biopsy samples were collected before and after treatment to determine if brushing induced dermal inflammation and melatonin increased the proportion of anagen follicles. Proportionally, left thigh hairs were significantly longer compared to lumbosacral hairs 2 months postclipping. No significant differences in hair regrowth were noted between the nontreated thigh and the thigh treated with melatonin or brushed. No significant difference in dermal inflammation was noted before and after brushing. No significant differences were observed in the proportion of anagen follicles before and after topical melatonin treatment. Our results showed that the hairs in the lumbosacral region were proportionally shorter than lateral thigh hairs 2 months postclipping. Moreover, topical melatonin and brushing had no impact on hair regrowth after clipping normal dogs.     

Histology of the hair cycle in male beagle dogs

A detailed histologic study of the hair follicles of male Beagle dogs was made to determine changes in microscopic structure associated with the three stages in the hair cycle. Observed changes are that the bulbs of hair follicles in anagen are more closely associated with adipose tissue than they are in telogen. This is due to the deeper penetration of the follicles into the subcutaneous tissue during anagen. The hair germ cells of telogen were presumed to arise from the stratum basale of the matrix cells rather than from the outer root sheath cells. During telogen, the dermal papilla is separated from the club hair, but remains in close proximity to it. There is no connecting stalk as is reported for other animals.     

内蒙古绒山羊Homeoboxc9基因在皮肤毛囊中的表达

试验通过原位杂交检测Homeoboxc9（Hoxc9）基因在皮肤毛囊中的表达情况,结果显示Hoxc9在胚胎期75 d的上皮细胞中表达,伴随着毛囊的生长发育,Hoxc9基因分别在初级毛囊的毛母质、毛乳头、内根鞘、外根鞘和毛干几个部位表达;在次级毛囊的内根鞘和绒干表达。在这个过程中毛囊角质化细胞大量增殖,表明在毛囊发育中Hoxc9基因对于角质化细胞的增殖可能起一定作用。     

Treatment of canine otitis externa using video otoscopy

Otitis externa in 27 toy poodles and 40 miniature dachshunds was treated using a video otoscope. A distinct concavity (external tympanic concavity) was observed at the junction between the ventral part of the external surface of the tympanum and the ear canal to which a considerable amount of hair and debris had adhered. All hair and debris adhering to the external tympanic concavity were removed, and systemic antibiotic and antifungal agents were administered, after which all of the dogs recovered. The pattern of hair growth observed in the external tympanic concavity could be characterized according to the breed of dog. All of the toy poodles presented with curly hairs, while the miniature dachshunds had upright or flat-lying hairs.     

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.     

Clear cell trichoblastomas in two dogs

Two cases of clear cell trichoblastomas were diagnosed in young dogs. The tumour had ribbons of basaloid cells as seen in ribbon trichoblastomas, as well as differentiation to external root sheath of the hair follicle and few cells with sebaceous differentiation. This is the first report of clear cell trichoblastoma in dogs.     

Histological organization of collared peccary (Tayassu tajacu) lip

Collared peccary (Tayassu tajacu) belongs to the Tayassuidae family that is characterized by a dorsal scent gland located in the middle of the hump. It can be found from south-west United States to Argentina. It is a very well-adapted animal that can survive different environments, having a varied diet. Very little morphological information of the animal is available, except that concerning the reproductive tract. This study describes the histological organization of the collared peccary lip. The lip marks the junction between the integument and digestive system. It is lined by skin on the outer surface and mucosa on the inner surface. Skin appendages such as hair follicles and glands are usually found on the outer surface. The collared peccary's lip shows, on the outer surface, simple and sinus hair follicles as well as sebaceous and apocrine sweat glands. No salivary gland is found on the inner surface, and deep in the connective tissue pacinian corpuscles can be found. The connective tissue is rich in collagen and elastic fibres. The collared peccary's lip may be used not only for food prehension but also functions as a sensitive structure giving tactile input to the central nervous system.     

The afferent innervation of the face of sheep and goats

The sensory innervation of the maxillary hairy skin and buccal mucous membrane was studied in anaesthetised sheep and goats. An electrophysiological technique isolated 47 single afferent units from the infraorbital nerve under chloralose or halothane anaesthesia. Mechanoreceptors of hairy skin were located in association with the following features: sinus hairs (n = 9); central primary hairs (n = 18); clear marginal hairs (n = 7) and skin-not-hair (n = 3). Units responded to hair tip displacement of 35 to 50 microm. Afferent units were also located in the mucous membrane of the cheek either associated with conical papillae (n = 8), or unassociated with papillae (n = 1). Receptor responses associated with hairs were classified as rapidly adapting (n = 18) and slowly adapting (n = 18) mechanoreceptor responses during sustained hair deflection. Seven mechanoreceptors of hairy skin and mucous membrane were excited by a fall in surface temperature. Two specific cold thermoreceptors were found: one in hairy skin and one in the mucous membrane. These units had phasic discharges during abrupt thermal depression and static discharges at constant surface temperatures. All afferent units had myelinated axons as indicated by their conduction velocities (range 20 to 57 m sec-1, mean 34 m sec-1). It is concluded that the mechanoreceptors identified had similarities with those of other mammalian species and some distinct differences. An interesting feature of mechanoreceptors in the buccal mucosa was their cold sensitivity. They therefore shared characteristics with mechanoreceptors in the penile mucosa of the ram and tongue of the sheep.     

Proliferative and necrotizing otitis externa in four cats

Proliferative and necrotizing feline otitis externa is a rare disorder of unknown aetiology. This condition was diagnosed by skin biopsy in three adult domestic shorthair cats (3-5 years old) and one kitten (6 months old). The affected cats had large tan to dark brown-black coalescing plaques covering the concave surface of the pinnae and external ear canals. Friable material from the plaques and a thick exudate occluded the ear canals. The cats had a secondary bacterial and/or yeast otitis. Prior to the histopathological diagnosis, all cats received numerous otic preparations as well as oral antibiotics and corticosteroids without resolution. Histologically, all cases had strikingly similar changes; acanthosis with pronounced hair follicle outer root sheath hyperplasia and neutrophilic luminal folliculitis, follicular keratosis and individually necrotic keratinocytes in the outer root sheath of hair follicles. One case was documented via skin biopsy to have persisted for 4 years. The adult cats were treated with topical 0.1% tacrolimus and all showed marked improvement although one cat was lost to follow up. The lesions completely resolved with topical tacrolimus alone in one cat and topical tacrolimus in addition to oral prednisolone in another cat.     

Expression analysis of the type I keratin protein keratin 33A in goat coat hair

The coat of a goat, like that of many mammalian species, consists of an outer coat of coarse hairs and an under coat of fine, downy hairs. The coarse guard hairs are produced by primary follicles and the finer cashmere hairs by secondary follicles. We previously reported that hair keratins are components of cashmere hair, and proteomic analysis revealed that their expression is elevated in winter coat hair. To determine detailed characterization, we have cloned keratin 33A gene, a major highly expressed keratin in winter, and then analyzed the expression of goat hair coat. By Western analysis, we detected that keratin 33A protein is expressed only in hair coat among the various goat tissues. Moreover, the expression level in winter has increased in cashmere high‐producing Korean native breed, whereas the expression levels between summer and winter had not changed in cashmere low‐producing Saanen. In addition, by immunohistochemistry we determined that keratin 33A is localized in the major cortex portion of cashmere fiber. These results confirm that keratin 33A is a structural protein of goat cashmere hair fiber.     

Vergleichende Untersuchungen an Haaren von Labortieren

Comparative examinations on the hairs of laboratory animals
In the white mouse the bristle hairs were on the average 8mm, in the awn hairs 7mm, and the fur hairs 6.5mm long. The values for the white rat were 19mm for the bristle hairs, 11mm for the awn hairs, and 7mm for the fur hairs; they were thus markedly longer. The hairs of the guinea-pig and of the rabbit were two- and three times as long. Hair thickness—especially at the thickest point—was distinctly different for the bristle and awn hairs, while these measurements of the fur hairs did not differ very much among these species. The size of the cuticle scales did not differ much between mouse, rat and rabbit. The medulla of the bristle and awn hairs of mouse and rat and that of the awn hair of the guinea-pig looked similar. However, the medulla of the rabbit was easily distinguished from the other species. The medulla of the fur hairs was constricted only in the mouse and rat. It is possible to identify with certainty the hairs of these four species if complete hair samples are available and if the microscopic measurements given here are taken into consideration.     

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.     

埋植褪黑激素的水貂冬季直针毛生长过程及鳞片形态性状研究

为研究埋植褪黑激素的水貂(Mustela vison)冬季直针毛生长过程及形态学性状的特点,测量埋植褪黑激素后31 d、62 d和75 d的水貂鲜皮腹部、背部和臀部新生冬季直针毛的毛长度、毛最粗处细度、毛根无髓段长度及毛根扁平型鳞片总长度等形态学指标。统计分析结果表明:埋植褪黑激素31 d后,水貂3个部位均出现了新生冬季直针毛;且臀部的新生冬季直针毛的毛长度最大,单位面积上新生冬季直针毛数量最多。埋植褪黑激素后31 d至62 d冬季直针毛的平均生长速度为:腹部(0. 33±0. 07) mm/d、背部(0. 44±0. 07) mm/d、臀部(0. 45±0. 08) mm/d,埋植褪黑激素后62 d至75 d冬季直针毛的平均生长速度为:腹部(0. 25±0. 06) mm/d、背部(0. 29±0. 10) mm/d、臀部(0. 36±0. 03) mm/d,均表现为臀部>背部>腹部的情形。埋植褪黑激素后31 d至62 d的冬季直针毛平均生长速度较快;埋植褪黑激素后62 d至75 d的冬季直针毛平均生长速度降低。冬季直针毛的长度与毛根无髓段长度、毛根扁平型鳞片总长度相关性不显著(P>0. 05);毛最粗处细度与毛根无髓段长度、毛根扁平型鳞片总长度相关性不显著(P>0. 05);毛根无髓段长度与毛根扁平型鳞片总长度呈极显著正相关(P <0. 01)。判断水貂取皮时间时,可以选择冬季直针毛的毛根无髓段长度作为指标。     

Immunohistochemical localization of fibroblast growth factor 18 in hair follicles of healthy beagle dogs

Increasing emphasis is being placed on the role of fibroblast growth factors (FGFs) in hair follicle cycling. In mice, expression of FGF18 mRNA peaks during the late telogen phase, leading to the hypothesis that FGF plays a role in anagen induction. There are no data on the presence of FGF18 in dogs. The main objective of this study was to identify and locate FGF18 in the canine hair follicle. The second objective was to assess potential differences in FGF18 concentration between biopsies taken in winter and summer, shoulder and flank regions, and between different sexes. Skin tissue from 10 healthy beagle dogs (three intact females, three spayed females and four intact males) was collected from the shoulder and flank. The biopsies were collected in February and August on day 0, after which the dogs were clipped and biopsies collected again from the shoulder and flank on days 1, 3, 7 and 17. Paraffin sections (4 μm thick) of the biopsies were stained with an anti-FGF18 antibody. The FGF18-positive cells were counted in the hair follicle epithelium from seven follicular units of each biopsy. Fibroblast growth factor 18 was detected as granular cytoplasmatic staining in follicles at the level of the inner root sheath, and rarely in the outer root sheath and dermal papilla. It was also detected in the apocrine glands, in arrector pili muscles and in vascular endothelial cells. There was no statistical difference in the number of FGF18-positive cells or follicles between sexes, different anatomical locations, seasons or the consecutive days of sampling.     

Alopecia in the horse – an overview

Dr Stannard explains different forms of alopecia in the horse with emphasis on the hair follicle and its function in the production of hairs. Both normal and abnormal patterns of hair growth and shedding in the horse are reviewed. Overviews of several specific hair follicle abnormalities, both inflammatory and noninflammatory, are discussed in detail with their clinical relevance. Some of the clinical entities covered in this section (linear alopecia and alopecia areata) are caused by immunological attack against normal structures and could have been placed in Immunologic diseases. However, because the clinical presentation for these entities is alopecia, Dr Stannard chose to include them in his notes on alopecia. Other inclusions in this section include cutaneous bacterial infections (e.g. pastern folliculitis and dermatophilosis) as well as fungal infections of the hair (dermatophytosis).     

用HPLC-MS/MS研究动物毛发中克伦特罗的残留及代谢规律

研究建立了高效液相色谱-串联质谱(HPLC-MS/MS)测定毛发中盐酸克伦特罗残留的方法。猪毛发以0.1moL/L盐酸溶液提取,MCX固相萃取柱净化,流动相溶解定容。以SB-C18柱为分离柱,1%乙酸水溶液和甲醇(60∶40,V∶V)作为流动相,MS/MS进行定性和定量分析。在优化条件下的最低检出限为0.05μg/kg,定量限为0.2μg/kg。毛发样品中添加不同浓度盐酸克伦特罗,测得回收率在79.0%～86.2%之间,变异系数均低于15.2%。应用该方法研究了盐酸克伦特罗在猪毛发中的代谢并初步探讨其代谢机理。结果表明:在较高饲喂浓度(10mg/kg)时,用药5d后,黑色猪毛发有少量盐酸克伦特罗残留,而白色猪毛发中未检出。从第7天起猪毛发中盐酸克伦特罗蓄积量逐渐增加,最高蓄积浓度为4852.5μg/kg。     

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)     

Effects of different dietary protein levels and DL‐methionine supplementation on hair growth and pelt quality in mink (Neovision vision)

The effect of different dietary protein levels and DL‐methionine (Met) supplementation on hair growth and the resulting pelt quality in mink was studied. Four groups of male mink were fed with four isocaloric diets containing 32% (P32), 24% (P24), 16% (P16) or P24+Met (0.8%) crude protein of dry matter (DM) from September to December. Skin biopsies were taken at the pelting. Histological techniques and computer‐assisted light microscopy were used to determine the ratio of activity (ROA) of under hairs and guard hairs respectively. The results showed that when the dietary protein level reduced from 32% to 16%, body length, number and diameter of under hairs and guard hairs of minks declined, and pelt length and pelt weight of minks decreased significantly (p < 0.05). These parameters were similar between P32 and P24 with Met supplementation (p > 0.05). The hair follicle density of the winter coat was not influenced by the dietary protein levels and Met supplementation (p > 0.05). Low‐protein diets content led to a reduction of hair follicle developing to next phase. It was documented that 24% crude protein of DM with Met supplementation during growing‐furring period was sufficient for minks to express their genetic capacity to develop hair follicles and achieve the prime fur characteristics. Overall this study demonstrated that hair growth and hair properties in pelts are very dependent on the dietary protein and Met supply in the growing‐furring period of minks.     

Development of the Equine Venous Sinuses of the Dura Mater

The equine dorsal sinus system of the dura mater develops from the dural venous plexuses. In early development, venous blood from these plexuses is drained into the primary head vein, which together with the stem of the caudal dural plexus joins the primitive internal jugular vein. After involution of the primary head vein new channels, the transverse and sigmoid sinuses, develop which empty into the internal jugular vein. The temporal sinus develops secondarily and coexists with the sigmoid sinus. After regression of the sigmoid sinus and internal jugular vein, the temporal sinus represents the sole channel in the equine fetuses, by which venous blood from the brain is drained through the emissary vein of the retroarticular foramen into the external jugular system.