House dust and forage mite allergens and their role in human and canine atopic dermatitis

This article reviews the literature regarding the role of house dust and forage mite allergens in canine atopic dermatitis. The presence of immunoglobulin E (IgE) to these mites, especially to Dermatophagoides farinae, is common in both normal and atopic dogs. Exposure of dogs to the different mites is described both in the direct environment and in the coat of animals for house dust mites and in the food for forage mites. Allergens causing allergic disease in dogs seem to be different from those in humans. Dogs seem to react to high molecular weight allergens, compared to the low molecular weight group 1 and group 2 proteases that are commonly implicated in humans with atopic diseases. Despite numerous published studies dealing with this subject, a number of questions still need to be addressed to better understand the exact role of these mites in the pathogenesis of canine atopic dermatitis and to improve the quality of the allergens used in practice.     

Inverse association between endotoxin exposure and canine atopic dermatitis

The development of canine atopic dermatitis (CAD) may be related to exposure to mite allergens, bacterial endotoxin and/or fungal glucans. In this study, indoor exposure levels of house dust mite allergens, endotoxins and fungal glucans were measured to determine their possible association with CAD. A case-control study including adult Labrador retrievers with (n=28) and without (controls; n=65) CAD was conducted. Dust samples were collected from the living room floor and the bedding and coat of the dog and these were analyzed for house dust mite allergens Der p1 and Der f1, endotoxin and (1→3)-β-d-glucan levels. Dog owners were also required to return a questionnaire regarding their home characteristics. The endotoxin exposure level in the coats of dogs was significantly inversely associated with CAD (odds ratio 0.38; 95% confidence interval 0.15-0.97; P<0.05). No significant difference was found in exposure levels to house dust mite allergens and fungal glucans. The results indicated that endotoxin exposure is inversely associated with CAD, suggesting a protective effect of high indoor endotoxin exposure towards the development of the condition.     

Discoid Lupus Erythematosus in Cats

Abstract— The clinical and histopathological features of discoid lupus erythematosus (DLE) are described in four European short-haired cats. Pinnal involvement seems to be highly predictable in feline DLE. In addition an indication exists for the initiating role of exposure to the sun in this disease.
Résumé— Les aspects cliniques et histopathologiques du lupus érythémateux discoide (DLE) sont décrits chez quatre chats européens à poils courts. L'atteinte du pavilion auriculaire semble très fréquente dans le DLE félin. En outre, l'exposition au soleil semble jouer un röle déterminant dans cette entité nosologique.
Zusammenfassung— Die klinischen und histopathologischen Merkmale des diskoiden Lupus erythematosus (DLE) bei vier Europäisch-Kurzhaarkatzen werden beschrieben. Beim felinen DLE scheint die Pinna regelmäßig mitbetroffen zu sein.
Nach dieser Untersuchung besteht Anlaß zur Vermutung, daß die Sonnenexposition bei dieser Krankheit eine auslösende Rolle spielt.     

Investigations on the role of flea antigen in the pathogenesis of German shepherd dog pyoderma (GSP)

Skin reaction patterns to the intradermal injection of a whole-body flea extract were examined in five physically healthy dogs and in 24 dogs with German Shepherd dog Pyoderma (GSP) at 15 and 30 minutes and at 1, 2, 4, 8, 24, 48 and 72 hours after the injection. In 10 out of 24 GSP dogs a positive skin reaction was observed macroscopically after 15 minutes. Delayed reactions at 24 or 48 hours were not observed. In the control group neither immediate nor delayed reactions were observed. The histopathologic skin changes were basically the same in both groups: an initial polymorphonuclear reaction followed by a mononuclear cell reaction. In the GSP dogs, however, these changes occurred earlier and were more prolonged than in the normal dogs. No flea-antigen-specific IgGd antibodies could be demonstrated by enzyme-linked immunosorbent assay. It is concluded that delayed type hypersensitivity to flea antigen does not play a role in the pathogenesis of GSP. Immediate type hypersensitivity may contribute to the disease in some cases.     

Investigations on the role of flea antigen in the pathogenesis of German Shepherd dog Pyoderma (GSP)

Summary

Skin reaction patterns to the intradermal injection of a whole‐body flea extract were examined in five physically healthy dogs and in 24 dogs with German Shepherd dog Pyoderma (GSP) at 15 and 30 minutes and at 1, 2, 4, 8, 24, 48 and 72 hours after the injection. In 10 out of 24 GSP dogs a positive skin reaction was observed macroscopically after 15 minutes. Delayed reactions at 24 or 48 hours were not observed. In the control group neither immediate nor delayed reactions were observed.

The histopathologic skin changes were basically the same in both groups: an initial polymorphonuclear reaction followed by a mononuclear cell reaction.

In the GSP dogs, however, these changes occurred earlier and were more prolonged than in the normal dogs. No flea‐antigen‐specific IgGd antibodies could be demonstrated by enzyme‐linked immunosorbent assay.

It is concluded that delayed type hypersentitivity to flea antigen does not play a role in the pathogenesis of GSP. Immediate type hypersensitivity may contribute to the disease in some cases.     

CHARACTERIZATION OF PHYSIOLOGIC 18F‐FDG UPTAKE WITH PET‐CT IN DOGS

We evaluated the whole body distribution of 2‐deoxy‐2‐[18F]fluoro‐d ‐glucose (¹⁸F‐FDG) in seven beagle dogs using positron emission tomography/computed tomography. The mean and maximum standard uptake values (SUV) for various tissues were computed. The SUV of the aortic blood pool was 0.65±0.19. Moderate uptake was present in brain (3.40±1.01). Mild uptake was present in orbital muscles, soft palate, laryngeal and pharyngeal region, mandibular salivary gland, myocardium, liver, pancreas, kidney, and intestine. ¹⁸F‐FDG uptake would be normally higher in these tissues because of normal physiologic activity. Mean and maximum SUV values of the eye, skeletal muscle, bone tissue, spleen, adrenal gland, stomach, tongue, gall bladder, and lung were similar to or lower than that of the aortic blood pool. These data provide a normal baseline for comparing pathologic ¹⁸F‐FDG uptake.     

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.     

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.     

Guide to the internal morphology of the European eel, Anguilla anguilla (L.) (Pisces,Teleostei)

Morphological detail and topographical relationships of internal organs of the European eel are demonstrated by labelled photographs of microscopical sections and drawings of dissected material. Glass eels were used in the preparation of sections of the head. Blocks were selected from the trunk region of a 35 cm eel. They were sectioned in transverse planes, resulting in a series of complete transverse sections through this region of the body. The macroscopical dissections were made on 50 cm silver eels.