Tandem repeats modify the structure of the canine CD1D gene.

Among the CD1 proteins that present lipid antigens to T cells, CD1d is the only one that stimulates a population of T cells with an invariant T-cell receptor known as NKT cells. Sequencing of a 722 nucleotide gap in the dog (Canis lupus familiaris) genome revealed that the canine CD1D gene lacks a sequence homologous to exon 2 of human CD1D, coding for the start codon and signal peptide. Also, the canine CD1D gene contains three different short tandem repeats that disrupt the expected gene structure. Because canine CD1D cDNA lacks sequences homologous to human exon 2 and 3, the functionality of canine CD1d protein may be affected, and this could have consequences for the development and activation of canine NKT cells.

Localised pyogranulomatous dermatitis due to Mycobacterium abscessus in a cat: a case report.

A case of pyogranulomatous dermatitis, caused by Mycobacterium abscessus, an unusual opportunistic Mycobacterium spp., is described in a cat. Histopathological examination of the affected skin confirmed the diagnosis and Ziehl-Neelsen staining revealed acid-fast rods. A rapidly growing mycobacterium was found after culture on a Löwenstein-Jensen medium. Real-time polymerase chain reaction for the 16S rDNA (434bp) sequence and the sequence of the rpoB gene (359bp) revealed 99% and 100% matches, respectively, with M. abscessus. This is the first report of a feline infection caused by this organism in Europe.

Dermatophagoides farinae-specific immunotherapy in atopic dogs with hypersensitivity to multiple allergens: a randomised, double blind, placebo-controlled study.

A randomised, placebo-controlled, double blind study was conducted on 25 dogs that had atopic dermatitis, together with skin test reactivity and elevated serum IgE to Dermatophagoides farinae (Df) and at least one additional allergen. Dogs were treated with either a Df-restricted immunotherapy solution (n=14) or a placebo (n=11) and evaluated 6 weeks and 3, 5, 7 and 9 months after the initiation of treatment using a clinical scoring system (SASSAD) and pruritus analogue scale scores. The Df-restricted solution and the placebo had an equal effect on both pruritus and the skin manifestations (P>0.05). The results of this study indicate that in dogs with atopic dermatitis based on hypersensitivity to environmental allergens in addition to D. farinae, Df-restricted immunotherapy is insufficient to control the disease. Consequently, a solution for allergen-specific immunotherapy should remain customised.

Non-pruritic granuloma in Norwegian forest cats.

The eosinophilic granuloma complex is a group of skin disorders common in cats. This paper describes the clinical, haematological and histopathological features of 17 related Norwegian forest cats, six of which had a linear granuloma on the caudal thigh, three of which also had a granuloma on the lower lip, and one of which had a granuloma in combination with an indolent ulcer. The high prevalence of the disease in this population is suggestive of a genetic background.

The effect of haloperidol and naloxone on excessive grooming behavior of cats.

In a double-blind cross-over study the effect of a single injection of naloxone (1 mg/kg s.c.) was investigated in 12 cats which suffered from excessive grooming with subsequent coat damage. Based on clinical observations and reports of the owners, naloxone had a beneficial effect on grooming which lasted between 2.5 weeks and 6 months (median 3 months). In another double-blind placebo-controlled study the effect of a single injection of haloperidol (2 mg/kg i.v.) was investigated in 20 cats with excessive grooming. Within 24 h haloperidol significantly reduced the time spent grooming. Four months after the injection no effect remained in nine of 10 cats injected with a placebo solution, whereas six of 10 cats injected with haloperidol the improved condition of the coat was maintained. It is hypothesized that naloxone is only effective in counteracting recently developed stereotypic behaviors and that haloperidol rather reduces stereotyped behaviors over a longer period.

The significance of reactions to purified fractions of Dermatophagoides pteronyssinus and Dermatophagoides farinae in canine atopic dermatitis.

The significance of reactions to crude extracts and purified fractions of the house dust mites Dermatophagoides pteronyssinus (Der p I and Der p II) and Dermatophagoides farinae (Der f I and Der f II) was evaluated in dogs with clinical manifestations of atopic dermatitis (AD). In 13 healthy control dogs and eight dogs with AD, immediate skin test reactivity was determined to serial dilutions of Der p I, Der p II, Der f I and Der f II. In addition, allergen-specific IgGd antibodies were determined by means of an enzyme-linked immunosorbent assay (ELISA) and Western blots. The results suggest that, in contrast to what occurs in humans and despite immediate skin test reactivity in some dogs, Der p I, Der p II, Der f I and Der f II are unlikely to be major allergens in dogs with AD. However, only serum of atopic dogs consistently binds a 90 kDa polypeptide of D. farinae, as shown by Western blot analysis.

Leukocyte mobilization to skin lesions, determination of cell surface receptors (CD11b/CD18) and phagocytic capacities of neutrophils in dogs with chronic deep pyoderma.

A suction blister technique was used in eight dogs with chronic deep pyoderma to determine chemotaxis in vivo. By flow cytometry the expression of adhesion molecules (CD11b/CD18) on exudative and peripheral neutrophils were analyzed in 11 healthy dogs and six dogs with chronic deep pyoderma. Phagocytosis in vitro capacities of exudative and peripheral neutrophils were analyzed in six healthy dogs and six dogs with chronic deep pyoderma. Dogs with chronic pyoderma showed significantly better chemotaxis in vivo compared with the healthy dogs (P < 0.05). Expression of adhesion molecules CD11b and CD18, and phagocytosis was significantly (P < 0.05) better in the dogs with pyoderma compared with the healthy dogs. In both groups exudative cells expressed significantly (P < 0.05) more CD11b/CD18 receptors compared with blood neutrophils. We conclude that there are no serious functional disturbances detectable in the peripheral neutrophils, nor in the exudative neutrophils from dogs with chronic deep pyoderma.

Immune dysregulation in atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disease in humans and dogs with comparable clinical features. Comparative studies of immunological events in the pathogenesis of AD may contribute to understanding of the disease in dogs and to development and evaluation of immunomodulatory strategies of relevance to both species.Both allergen-specific as well as non-specific mechanisms contribute to the disease development. AD skin lesions are proposed to be initiated by activation of allergen-specific Th2-type cells, potentially influenced by local cutaneous factors. In the chronic stage of skin lesions reactivity may change into a Th1-type, e.g. driven by eosinophil derived IL-12. Analyses of these processes in course of time were performed in both spontaneous as well as in experimentally induced lesions (i.e. atopy patch test (APT) lesions). In the present paper, the immunological events as reported for human and canine AD are summarized and compared.

Immunophenotyping of skin-infiltrating T-cell subsets in dogs with atopic dermatitis.

Atopic dermatitis in dogs has many clinical features that are identical to those of the same disorder in man. To investigate the pathogenesis of this disease in dogs and the possibility of similarities to the pathogenesis in humans we compared the presence and ratio of CD4+ and CD8+ T-cells in the cutaneous infiltrate of lesional and non-lesional skin of atopic dogs with that in the skin of healthy dogs. In ten dogs with atopic dermatitis and ten healthy dogs the skin was biopsied at the predilection sites for atopic dermatitis and histological sections were immunohistochemically stained for CD4 and CD8. The staining showed an increase in CD4+ and CD8+ T-cells in canine lesional atopic skin, with a predominance of CD4+ T-cells in the epidermis. In non-lesional atopic skin there was also an infiltration with CD4+ and CD8+ T-cells, but without predominance of CD4+ T-cells. The results in the separate predilection sites did not differ substantially from the mean results. These observations indicate further similarities in the immunopathogenesis of atopic dermatitis in dogs and humans, which may have consequences for the control of atopic dermatitis in dogs and contributes to a possible role of the dog as a model for human atopic dermatitis.

Immunophenotyping of the cutaneous cellular infiltrate after atopy patch testing in cats with atopic dermatitis.

Cats with spontaneously occurring atopic dermatitis have clinical and immunocytochemical characteristics compatible with these in humans with atopic dermatitis (AD). The atopy patch test (APT) has proven to be a valuable tool in elucidating the disease process in humans. Additionally, the APT is very specific and bypasses the problem of conflicting results due to differences in chronicity of lesions of AD patients. We adapted the APT for use in cats to explore the suitability of the APT as a tool to study the onset of allergic inflammation in cats with atopic dermatitis. APT were performed in AD cats (n = 6) and healthy cats (n = 10). All cats were patch tested with two allergens in three different dilutions and a diluent control. The allergens for the APT were selected from positive intradermal test and /or prick test results and consisted of: Dermatophagoides farinae, D. pteronyssinus, Tyrophagus putrescentiae, and a grass pollen mixture. APT were read after 10, 24 and 48 h, and punch biopsies for immunohistochemical evaluation were collected at these time points. Macroscopically positive APT reactions were observed in three out of six cats at 24 and/or 48 h with allergen concentrations of 25,000 and 100,000 NU/ml. Reactions were not observed at negative control sites and neither in control animals. A significantly increased number of IL-4+, CD4+, CD3+, MHC class II+ and CD1a+ cells was found in one AD cat with positive APT reactions. Five out of six AD cats had significantly increased IL-4+ T cell numbers at 24 and/or 48 h. Our data indicate that in cats, macroscopically positive patch test reactions can be induced, which have a cellular infiltrate similar to that in lesional skin. We found a high specificity and a macroscopically positive APT reaction in half of the cats, which is similar to what is seen in humans. Hence, the APT in cats might be a useful tool in studying the immunopathogenesis of feline atopic dermatitis.

Mast cells and eosinophils in feline allergic dermatitis: a qualitative and quantitative analysis.

Mast cells (MCs) and eosinophils are prominent in the perivascular infiltrate of cats with allergic dermatitis. In the skin of allergic cats MCs were mainly observed diffusely in the superficial dermis, while eosinophils were found mainly in the deep dermis in a perivascular pattern. MC counts were significantly higher in cats with allergic dermatitis (P < 0.05) than in healthy control cats, but the number varied widely. Moreover, the numbers of eosinophils in the skin of allergic and control cats differed significantly (P < 0.05) none being found in the latter. There was no significant correlation between numbers of mast cells and eosinophils in the same biopsy sample. In the allergic cats, a significantly lower number of MCs was detected by staining for tryptase than by staining for chymase or by Astra blue staining. Additionally, the chymase: tryptase ratio in healthy cats was reversed in cats with allergic dermatitis. These changes were observed in lesional and nonlesional skin of cats with allergic dermatitis. The findings indicate a generalized effect on MCs in allergic dermatitis. In addition, eosinophils are an important indicator of allergic dermatitis.

Double-blind evaluation of two commercial hypoallergenic diets in cats with adverse food reactions.

The aim of this study was to evaluate two commercially available selected-protein-source diets as maintenance diets in cats with dermatological manifestations of adverse food reactions. Twenty cats with a confirmed adverse food reaction were tested in a double-blind manner. An adverse food reaction was diagnosed when, after recovery with a home-cooked elimination diet, the signs relapsed after a challenge with their previous dietary components, and re-disappeared on a second elimination diet period. Hereafter the cats were blind and randomly challenged with two commercial hypoallergenic diets. Relapse of the clinical signs was seen in eight cats (40%) on a lamb and rice diet and in 13 cats (65%) on a chicken and rice diet (P>0.05). Neither one of the commercial diets was as effective in controlling the skin problems as the home-cooked elimination diet. The study confirms that commercial hypoallergenic diets are adequate for maintenance.

Comparison of in vivo and in vitro corticotropin-releasing hormone-stimulated release of proopiomelanocortin-derived peptides in cats.

In 6 cats, the effect of IV administration of various concentrations of ovine corticotropin-releasing hormone (oCRH) on plasma concentrations of cortisol, alpha-melanocyte-stimulating hormone (alpha-MSH), and adrenocorticotropic hormone (ACTH) was measured. After administration of 1.0 microgram of oCRH/kg of body weight, significant (P < 0.05) increases in plasma cortisol, alpha-MSH, and ACTH concentrations were observed. After administration of 0.1 microgram of oCRH/kg, significant increases were found only for cortisol and ACTH concentrations. In vitro release of ACTH from dispersed feline pars distalis cells in primary culture stimulated by oCRH and arginine vasopressin (AVP) was dose-dependent. Maximal stimulation was achieved by 1 nM oCRH or 100 nM AVP. The oCRH-stimulated ACTH release was partially inhibited by dexamethasone, and AVP-induced release was completely inhibited. Pars intermedia cells released 20 times as much alpha-MSH as ACTH. A dose-dependent inhibition of alpha-MSH release was induced by the dopamine agonist, bromocriptine. This inhibition could be partially abolished by coincubation with haloperidol. Bromocriptine had no effect on release of ACTH. In conclusion, oCRH stimulates the pars distalis and pars intermedia of the pituitary gland of cats. Release of ACTH is stimulated by a direct effect on the pars distalis. In addition, in cats, oCRH is a more potent secretagogue than is AVP. The MSH release from the pars intermedia is sensitive to dopaminergic inhibition, indicating that dopamine may have a central role in regulation of MSH secretion in cats.

Leukocyte mobilization to skin lesions in dogs.

A suction blister technique was used in 10 healthy dogs to remove the epidermis from the dermis in a standardized way. Collection chambers were attached to these skin windows and filled with autologous serum to attract exudative neutrophils. The chambers were emptied by fine-needle aspiration at 4-hour intervals and were refilled with serum for 24 hours after the last aspiration. The collected cells were counted, differentiated, and stained, using the trypan blue dye-exclusion method to determine cell viability. Multiple skin biopsy specimens obtained during the procedure were examined histologically. The chamber fluid collected after 24 hours was cultured for bacteria. Increasing numbers of viable neutrophils were collected during the 24-hour period from the induced skin windows. In all but 1 dog, sufficient viable neutrophils could be collected to perform further functional tests in vitro. Our conclusion is that this technique might be useful to study chemotaxis in vivo and to perform functional tests on exudative neutrophils.

Changes in plasma cortisol, corticotropin, and alpha-melanocyte-stimulating hormone concentrations in cats before and after physical restraint and intradermal testing.

In 6 cats, mean +/- SEM baseline plasma concentrations of cortisol, corticotropin, and alpha-melanocyte-stimulating hormone (alpha-MSH) were 87 +/- 16 nmol/L, 73 +/- 14 ng/L, and 129 +/- 12 ng/L, respectively. The cats were subjected to: handling and subsequent skin testing without anesthesia; anesthesia with 50 mg of ketamine HCl and 2.5 mg of diazepam given IV, immediately followed by handling and skin testing; and anesthesia and handling as previously described, but without skin testing. Significant (P < 0.05; multivariate analysis for repeated measures) increase in plasma cortisol, corticotropin, and alpha-MSH concentrations was observed until 20 minutes after the start of the experiments in cats undergoing physical restraint and subsequent skin testing with or without preceding anesthesia. These responses were largely abolished when anesthesia with ketamine and diazepam was only followed by handling. We conclude that, during stress in cats (in contrast to dogs), the pituitary intermediate lobe is activated to secrete alpha-MSH. In addition, the cortisol response after skin testing of cats under anesthesia may be a reasonable explanation for the reported weak skin test reactivity in cats.

Evaluation of selected-protein-source diets for management of dogs with adverse reactions to foods.

OBJECTIVE: To evaluate 3 commercially available selected-protein-source diets as maintenance diets in dogs with pruritus caused by adverse food reactions. DESIGN: Randomized crossover trial. ANIMALS: 40 dogs > 6 months of age with pruritus caused by adverse reactions to foods. PROCEDURE: Diagnosis was confirmed by use of diet elimination and provocation studies. Subsequently, dogs were fed 3 commercial diets for 3 weeks each in a randomized, blinded, crossover trial. Dogs were evaluated for pruritus, vomiting, diarrhea, and flatulence. RESULTS: Pruritus recurred in 52.5% of dogs fed a chicken-rice diet, 47.5% of dogs fed a catfish-rice diet, and 85% of dogs fed a venison-rice diet. Overall 95% of the dogs could be managed successfully with at least 1 of the 3 diets. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that commercially available limited-allergen diets with selected protein sources may be appropriate for long-term management of pruritus caused by adverse food reactions. Testing of various protein sources is usually required.

Cytophilic antibodies in cats with miliary dermatitis and eosinophilic plaques: passive transfer of immediate-type hypersensitivity.

Passive cutaneous anaphylaxis test and Praunitz-Küstner tests were performed in healthy recipient cats with heated and unheated sera of 17 cats suspected of having allergic dermatitis and of 12 healthy control cats. Positive reactions occurred with heated and unheated sera. It was therefore hypothesized that a heat-stabile cytophilic antibody is involved in the pathogenesis of eosinophilic plaques and miliary dermatitis in some cats.

A retrospective evaluation of adverse reactions to trimethoprim-sulphonamide combinations in dogs and cats.

Adverse reactions to various trimethoprim-sulphonamide (T-S) combinations were studied retrospectively in dogs and cats referred to the Utrecht University Department of Clinical Sciences of Companion Animals during the period 1985-1994. Dermatological and systemic reactions were observed in 19 dogs and 2 cats. Specific histological reaction patterns were seen in 3 dogs with toxic epidermal necrolysis, in 1 dog and 1 cat with erythema multiforme, and in 1 dog with pemphigus foliaceus. Diagnostic criteria used in humans proved to be reliable in dogs and cats as well. Adverse reactions were observed within 7-14 days after administration and were most often due to sulphadiazine (76%) and sulphatroxazole (14%). The incidence of adverse reactions to T-S was 0.25%.

Demodicosis in ferrets (Mustela putorius furo).

This report describes the clinical signs, diagnosis, and therapy of demodicosis in ferrets. Two ferrets (Mustela putorius furo) were presented with a history of local alopecia and pruritus after repeated treatment with a glucocorticoid-containing ointment for recurrent ear mite infections. Skin scrapings and biopsies revealed adult mites and larvae of Demodex spp., which were measured according to current classification techniques. Treatment with amitraz was effective and did not cause noticeable side effects. To the authors' knowledge this is the first report of demodicosis in ferrets.

A case of Ehlers-Danlos-like syndrome in a rabbit with a review of the disease in other species.

A case of marked skin fragility in a 4-month-old pet rabbit is described. The clinical findings, gross pathology, histopathology, and ultrastructure of skin samples were consistent with Ehlers-Danlos-like syndrome. This syndrome is recognized in many animal species and is often compared to Ehlers-Danlos syndrome in humans. Ehlers-Danlos-like syndromes in animals are reviewed and possible similarities between these disorders and Ehlers-Danlos syndrome in humans are discussed.