Omneity® Pellets
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Topic:Skin
The skin of horses is a complex organ that serves multiple functions, including protection, thermoregulation, and sensory perception. It consists of several layers, primarily the epidermis and dermis, each contributing to the overall health and functionality of the skin. The epidermis provides a barrier against environmental factors, while the dermis supports the skin structure and houses blood vessels, nerves, and hair follicles. Equine skin is also involved in the production of sweat and sebum, which aid in temperature regulation and skin lubrication, respectively. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and health conditions of equine skin, as well as advancements in dermatological treatments and care practices.
Rapid identification of tissue micro-organisms in skin biopsy specimens from domestic animals using polyclonal BCG antibody. Immunostaining with polyclonal anti-Mycobacterium bovis (BCG) was evaluated as a single screening method for the histological identification of micro-organisms in skin biopsy specimens from various veterinary species. Confirmed archival cases infected with Mycobacteria, Nocardia, Actinobacillus, Actinomyces, Streptococcus/Staphylococcus, Dermatophilus, spirochetes, Blastomyces, Coccidioides, Cryptococcus, Histoplasma, dermatophytes, Malassezia, Sporothrix, Leishmania, Pythium, phaeohyphomycetes and Prototheca organisms were selected. A total of 70 skin biopsy specimens from the dog, cat, horse...
Methodology and validity of assessing kinematics of the thoracolumbar vertebral column in horses on the basis of skin-fixated markers. To determine the validity of using skin-fixated markers to assess kinematics of the thoracolumbar vertebral column in horses. Methods: 5 Dutch Warmblood horses without abnormalities of the vertebral column. Methods: Kinematics of T6, T10, T13, T17, L1, L3, L5, S3, and both tuber coxae were determined by use of bone-fixated and skin-fixated markers. Three-dimensional coordinate data were collected while horses were walking and trotting on a treadmill. Angular motion patterns were calculated and compared on the basis of 2-dimensional analysis of data from skin-fixated markers and 3-dimensional a...
Identification of lidocaine and its metabolites in post-administration equine urine by ELISA and MS/MS. Lidocaine is a local anesthetic drug that is widely used in equine medicine. It has the advantage of giving good local anesthesia and a longer duration of action than procaine. Although approved for use in horses in training by the American Association of Equine Practitioners (AAEP), lidocaine is also an Association of Racing Commissioners International (ARCI) Class 2 drug and its detection in forensic samples can result in significant penalties. Lidocaine was observed as a monoprotonated ion at m/z 235 by ESI+ MS/MS (electrospray ionization-positive ion mode) analysis. The base peak ion at m/...
Effect of sodium bisulfate on skin and hooves of horses. To evaluate the safety of sodium bisulfate for use in horse barn environments by determining its irritant effect on skin and hooves. Methods: 6 female mixed-breed ponies. Methods: Sodium bisulfate was applied to clipped intact skin of 6 ponies to evaluate its irritant effect after single (48 hours) and repetitive (6 h/d for 10 days) applications; similar areas of skin were used as untreated control sites. In addition, sodium bisulfate was applied to the sole of both front hooves of each pony and covered with wet gauze, and the entire hoof was covered with adhesive tape for 48 hours. Results: C...
Diagnosis of equine arteritis virus infection in two horses by using monoclonal antibody immunoperoxidase histochemistry on skin biopsies. Two 5-year-old grade male horses presented with epiphora, rhinorrhea, conjunctival and nasal mucosal hyperemia, and dorsal and thoracic macropapular rash. Skin biopsies were collected from the affected areas, and serial sections were evaluated following hematoxylin and eosin and immunoperoxidase histochemistry staining by using a murine monoclonal antibody of the immunoglobulin G2A isotype recognizing the 30-kDa membrane protein of equine arteritis virus (EAV). In both horses, lesions consisted of mild to moderate diffuse superficial dermal edema and vasculitis with mild perivascular lymphocyt...
Cloning of equine chemokines eotaxin, monocyte chemoattractant protein (MCP)-1, MCP-2 and MCP-4, mRNA expression in tissues and induction by IL-4 in dermal fibroblasts. We report the cloning of four equine CC chemokines, eotaxin, monocyte chemoattractant protein (MCP)-1, MCP-2 and MCP-4, which show high levels of identity with their respective homologous sequences in other species. Using a multiplex RT-PCR, we have studied the constitutive mRNA expression of these four CC chemokines in skin, lung, liver, spleen, jejunum, colon and kidney of normal adult horses and compared this data with the eosinophil counts in the same samples. We demonstrate that eotaxin mRNA is only expressed in jejunum and colon, where there are large numbers of eosinophils suggesting th...
Dermatitis associated with “hypopodes” in a horse: the first case reported in Italy. The authors report, for the first time in Italy, a case of dermatitis of "hypopodes" origin in a horse. The hypopodes are a particular nymphal stage of mites of the suborder Astigmata. The "hypopus" is non-feeding, lacks a mouth and has a ventral suctorial plate with suckers and conoids for attaching itself to insects as a mode of dispersal. Some of these larval stages can enter into the hair follicles and into the subcutaneous layers causing lesions similar to mange. There are few reports of dermatitis in horses specifically associated with the presence of hypopodes and these have been attrib...
Miscellaneous. This section includes clinical conditions which have unique characteristics which make them unsuitable for inclusion in the first six sections. The clinical description, aetiology and histopathologic findings of the unusual ear lesion, aural plaques, are described. Dermatoses complicated by, or caused by, photosensitivity are discussed in regards to their aetiology and pathogenesis as well as clinical features. The suggestion that photosensitization plays a role in the development of the lesions seen in pastern leukocytoclastic vasculitis is made. This section ends with an in depth discussion ...
Immunologic diseases. Selected equine cutaneous diseases for which there is strong evidence of an immunological aetiology are discussed in this section. The reactive disorders of urticaria, Culicoides hypersensitivity, erythema multiforme, drug eruptions and systemic granulomatous disease are included. The autoimmune diseases of the horse with cutaneous manifestations (pemphigus foliaceus, pemphigus vulgaris, bullous pemphigoid and cutaneous lupus erythematosus) are discussed. The clinical signs and diagnostic features of these immunologically induced equine dermatoses are defined, and the challenges in making a de...
Nodular diseases. The development of a nodule is a fairly common reaction pattern in the skin and subcutaneous tissues of the horse. In many such nodules, the inciting aetiologic agent or antigen is unknown, but in some equine cases there is significant evidence for insect bite origin. The pathogenesis of some equine nodular diseases appears to involve marked collagen degeneration which varies from hyalinization to lysis and can become mineralized. The exact role the lytic collagen has in the pathogenesis of these lesions is still unknown. Vascular changes may be present in some entities. Other nodules may be c...
The effectiveness of the haemodialysate Solcoseryl for second-intention wound healing in horses and ponies. Second-intention healing of limb wounds in horses is often problematic. Solcoseryl is a protein-free, standardized dialysate/ultrafiltrate (HD) derived from calf blood, which has been shown to improve healing in both animals and humans. The efficacy of HD in the healing of deep wounds in horses and ponies was investigated. Deep wounds of 20 by 35 mm were created on both metatarsi (skin, subcutis, periosteum) and on both femoral biceps muscles (skin, subcutis, muscle) of five horses and five ponies. The wounds on one side were treated with HD, four times a week during the period that the wounds...
The kinetics of Langerhans cells in equine insect hypersensitivity “Kasen”. An immunohistochemical study was carried out on the kinetics of Langerhans cells (LCs) at various pathological stages of "Kasen". Skin lesions of "Kasen" that were collected by biopsy from May to October were classified histopathologically into three stages: initial (Group I, 31 cases), developing (Group II, 50 cases) and regressing (Group III, 13 cases). LCs showed a positive reaction with anti-equine thymocytes (EqT6) monoclonal antibody (MoAb) and anti-major histocompatibility complex (MHC) class II MoAb by immunohistochemical staining. The anti-EqT6 MoAb was intensely positive along the cy...
The study of cutaneous melanomas in Camargue-type gray-skinned horses (2): epidemiological survey. An epidemiological survey was made on cutaneous melanomas occurring in Camargue-type, gray-skinned horses in southern France. The population investigated was composed of 264 horses, which were selected from the Camargue horse stud registry and were allowed to be examined by the owners. The presence of tumors was inspected macroscopically according to the standardized protocols of veterinary medicine specialists, and some tumors were subjected to macroscopic histopathological examination. The results indicated that: 1) the prevalence of melanomas in the overall population was 31.4%; 2) the odds...
The study of cutaneous melanomas in Camargue-type gray-skinned horses (1): clinical-pathological characterization. The clinical and pathological characteristics of cutaneous melanomas occurring in Camargue-type gray-skinned horses are reported. Examination of 83 tumor-bearing horses revealed that the tumors occurred most frequently underneath the tail (93.9%) and at high rates in the peri-anal region (43.0%), the lips (33.0%), and the eyelids (24.0%), but rarely in the vulva (3.8%). Tumorous lesions were characterized by the presence of either hemispheric nodules or large infiltrated plaques, or their combinations. Microscopic examination indicated that tumorous lesions were composed mostly of melanocytes ...
Melanin affinity: a possible explanation of isoxsuprine retention in the horse. Isoxsuprine is used in veterinary medicine as a vasodilating agent. The drug has been detected in the urine of horses up to 6 weeks after the cessation of administration. In the present study, the distribution pattern of 3H-isoxsuprine was investigated using whole body autoradiography in mice to find a possible site of retention. Melanin was the only place of retention identified. Additional in vitro studies showed an affinity of isoxsuprine to both melanin and keratin. The K(d) values were 0.02 mmol/l and 1 mmol/l, and the B(max) values were 0.2 micromol/mg and 2 micromol/mg, respectively. A ...
Comparison of equine amnion and a nonadherent wound dressing material for bandaging pinch-grafted wounds in ponies. To evaluate healing of pinch-grafted wounds on the distal aspect of the limbs of ponies bandaged with equine amnion or a standard nonadherent wound dressing material. Methods: 6 ponies. Methods: A 2.5x2.5-cm full-thickness section of skin was removed from the dorsal aspect of each limb at the midpoint of the metacarpus or metatarsus. Six days later, wounds were grafted with partial-thickness pinch grafts. Half the wounds were bandaged with amnion, and the other half were bandaged with a nonadherent dressing. Bandages were changed every 3 days until wound healing was complete. At each bandage c...
Equine bullous pemphigoid IgG autoantibodies target linear epitopes in the NC16A ectodomain of collagen XVII (BP180, BPAG2). Bullous pemphigoid (BP) is an autoimmune subepithelial blistering dermatosis of humans, dogs, cats and pigs. It is characterized by skin-fixed and circulating IgG autoantibodies that target one or both BP antigens. An immunological homologue of BP in humans was diagnosed in two horses with cutaneous and mucosal ulcerations as well as microscopic subepithelial vesiculation. Immunological investigations revealed similar findings for both the horses. Direct immunofluorescence demonstrated the presence of IgG deposited linearly at the dermoepidermal junction in mucosal and skin biopsy specimens. I...
Staining abnormalities of dermal collagen in eosinophil- or neutrophil-rich inflammatory dermatoses of horses and cats as demonstrated with Masson’s trichrome stain. A retrospective study was performed on skin biopsy specimens from horses and cats having eosinophilic granulomas with 'collagen degeneration', eosinophilic skin diseases without 'collagen degeneration' and pyogranulomas without 'collagen degeneration'. Neither the appearance of collagen fibres nor the dominant polymorphonuclear cells, as seen in H & E-stained sections, were predictive of Masson's trichrome findings. Hence, a Masson's trichrome staining abnormality of collagen fibres was no more likely to be present in lesions with 'collagen degeneration' than in those lesions without 'coll...
Sweat production and localisation of carbonic anhydrase in the equine sweat gland during exercise at two ambient temperatures. The aim of this investigation was to study sweat production during exercise at 2 ambient temperatures (20 degrees C and 35 degrees C) and the concurrent localisation of carbonic anhydrase (CA) in the sweat gland. Horses develop alkalosis during prolonged exercise and the sweat contains HCO3-. Carbonic anhydrase is therefore of interest since it catalyses the reaction CO2 + H2OHCO3- + H+. Four standardbred trotters performed an exercise test. Skin biopsies were taken from the neck, and sweat rate, blood and skin temperatures were measured. There was a close relationship between sweat rate, temp...
Sweating and skin temperature responses of normal and anhidrotic horses to intravenous adrenaline. Anhidrosis has been recognised for over half a century, but despite some excellent epidemiological studies, there has been little progress in understanding the aetiology of the condition. Using a modified ventilated capsule, we obtained dynamic, quantitative data on sweating responses in anhidrotic horses and normal sweating controls from the same environment. Ten horses with current seasonal anhidrosis and 10 matched normal sweating controls were selected. Each horse was given two 10 min infusions of 1 and 2 micrograms/kg/min adrenaline, separated by at least 6 h. Sweating responses and skin ...
Experimental infection of ponies with Borrelia burgdorferi by exposure to Ixodid ticks. Seven specific-pathogen-free (SPF) ponies, 1-5 years old, were exposed to Borrelia burgdorferi-infected adult ticks while being treated with dexamethasone over 5 consecutive days. One SPF pony (pony No. 178) was first exposed to laboratory-reared nymphs without B. burgdorferi infection and 3 weeks later was exposed to B. burgdorferi-infected adult ticks with concurrent dexamethasone treatment for 5 consecutive days. Four uninfected ponies treated with dexamethasone, exposed to laboratory-reared ticks without B. burgdorferi infection served as uninfected controls. Clinical signs, bacteriologic ...
Characterisation of lymphocyte subpopulations in the skin and circulation of horses with sweet itch (Culicoides hypersensitivity). Circulating lymphocyte numbers are elevated in horses with the allergic skin disease sweet itch and skin lesions are typified by an infiltrate of eosinophils and mononuclear cells, the latter of which have not been fully characterised. The aim of the present study was to characterise the lymphocyte subpopulations in the circulation and skin of ponies with sweet itch by flow cytometry and a newly developed modified alkaline phosphatase immunohistochemical technique. Sweet itch ponies were found to have significantly greater numbers of circulating CD5+ and CD4+ T-lymphocytes than normal animals....
Injection site eosinophilic granulomas and collagenolysis in 3 horses. Three horses were presented with a history of having developed raised cutaneous nodules, within 24-48 hours, in areas of previous injections using standard silicone-coated hypodermic needles. Skin biopsies were taken from a selected cutaneous nodule from all horses for histopathologic evaluation. Histologically, the nodules were consistent with a diagnosis of equine eosinophilic granuloma. A hypersensitivity reaction to the silicone, or another component of the coating formulation, was hypothesized to be responsible for these lesions. Two horses were experimentally injected using both coated a...
Evaluation of iodophor skin preparation techniques and factors influencing drainage from ventral midline incisions in horses. To document natural bacterial flora on the ventral aspect of the equine abdomen, to compare 2 preparation techniques, and to identify potential risk factors that may contribute to incisional drainage. Methods: Prospective study. Methods: 53 horses undergoing exploratory celiotomy. Methods: Group-1 horses (n = 26) were prepared with povidone-iodine and alcohol. Group-2 horses (27) were prepared with a film-forming iodophor complex. Numbers of bacterial colony-forming units (CFU) were measured before and after surgical scrub, following skin closure, and after recovery from general anesthesia. Sw...
Identification of calcium-activated potassium channels in cultured equine sweat gland epithelial cells. The patch-clamp recording technique was used to examine the properties of the K+ channels in cultured equine sweat gland epithelial cells. With symmetric K+ solutions (140 mM), a single population of K+ channels was identified with a slope conductance of 187 pS and a reversal potential of around 0 mV. The channel was selective for K+ over Na+. Channel activity was increased by membrane depolarization. A 10-fold increase in [Ca2+]i produced an approximate 60 mV negative shift in the open state probability (Popen)-voltage curve. Externally applied tetraethylammonium ions (TEA+) caused a rapid an...
