Cytologic comparison of the percentage of mast cells in lymph node aspirate samples from clinically normal dogs versus dogs with allergic dermatologic disease and dogs with cutaneous mast cell tumors.

OBJECTIVE To compare percentages of mast cells in lymph node (LN) aspirate samples from clinically normal dogs, dogs with allergic dermatologic disease (ADD), and dogs with cutaneous mast cell tumors (MCTs). DESIGN Prospective cross-sectional study. ANIMALS 20 healthy dogs (group 1), 20 dogs with ADD (group 2), and 20 dogs with an MCT on the head or limbs (group 3). PROCEDURES LN aspirate samples were obtained from easily accessible LNs in group 1, affected skin regions in group 2, and the likely draining LN or LNs of the MCT in group 3; the percentage of mast cells was manually determined for each LN. For group 3, LNs were cytologically categorized with a modified version of a published metastasis categorization scheme. RESULTS Median (range) percentage of mast cells in aspirate samples was 0% (0% to 0.1%) for group 1, 0.05% (0% to 0.55%) for group 2, and 0.4% (0% to 77.4%) for group 3. In group 3, 16 LNs (13 dogs) were palpably normal in size; 6 of these had evidence of possible or certain metastasis. Seven LNs (7 dogs) in group 3 were palpably enlarged, and 5 of these had evidence of certain metastasis. CONCLUSIONS AND CLINICAL RELEVANCE This study provided evidence to support the use of a uniform cytologic grading system to further define nodal metastasis in dogs with MCTs as well as estimates of the percentage of mast cells in LN aspirate samples for healthy dogs and dogs with ADD. Palpably normal LNs in dogs with cutaneous MCT may contain metastasis.

Dorsal skin necrosis secondary to a solar-induced thermal burn in a brown-coated dachshund.

A 5-year-old neutered male brown dachshund dog was presented for a large dorsal cutaneous burn that occurred following direct sunlight exposure outdoors in high ambient temperatures. Although burns are quite common in dogs, full-thickness solar-induced radiation burns are less common and have not been previously reported in animals without a black hair coat.

Nécrose de la peau dorsale secondaire à une brûlure thermique induite par l'exposition au soleil chez un Dachsund à pelage brun. Un chien Dachsund brun stérilisé âgé de 5 ans a été présenté pour une grande brûlure cutanée dorsale qui s'était produite après une exposition directe au soleil à l'extérieur durant des températures élevées. Même si les brûlures sont assez courantes chez les chiens, les brûlures du troisième degré causées par l'exposition au soleil sont moins communes et n'ont pas déjà été signalées chez des animaux sans un pelage à poil noir.(Traduit par Isabelle Vallières).

Instabilities and spatiotemporal patterns behind predator invasions with nonlocal prey competition.

We study the influence of nonlocal intraspecies prey competition on the spatiotemporal patterns arising behind predator invasions in two oscillatory reaction-diffusion integro-differential models. We use three common types of integral kernels as well as develop a caricature system, to describe the influence of the standard deviation and kurtosis of the kernel function on the patterns observed. We find that nonlocal competition can destabilize the spatially homogeneous state behind the invasion and lead to the formation of complex spatiotemporal patterns, including stationary spatially periodic patterns, wave trains and irregular spatiotemporal oscillations. In addition, the caricature system illustrates how large standard deviation and low kurtosis facilitate the formation of these spatiotemporal patterns. This suggests that nonlocal competition may be an important mechanism underlying spatial pattern formation, particularly in systems where the competition between individuals varies over space in a platykurtic manner.

Adverse food reactions in dogs and cats.

Adverse food reactions (AFR) are a common problem that may cause cutaneous and/or gastrointestinal signs in dogs and cats. They comprise food intolerance, food intoxication, and food allergy. Response to a dietary elimination trial and recurrence of signs during dietary provocation remain the centerpiece of diagnosis and management of dogs and cats with AFR. Response to an elimination trial is frequently observed in dogs and cats with chronic idiopathic enteropathies. However, only a fraction of them relapse after a dietary challenge. These animals may have mild to enteritis and/or colitis and benefit from various additional properties of the elimination diet.

In vitro comparison of Staphylococcus pseudintermedius susceptibility to common cephalosporins used in dogs.

The in vitro activity of 10 cephalosporin antimicrobial agents against 75 isolates of methicillin-susceptible Staphylococcus pseudintermedius derived from dogs was assessed. The lowest minimal inhibitory concentration for 90% of strains (MIC90) values obtained were for cephalothin, cefovecin, and cefazolin (0.12 ug/mL), followed by ceftiofur and cefoxitin (0.25 ug/mL), cefpodoxime (0.5 ug/mL), and cefaclor and cefadroxil (1 ug/mL). The highest MIC90 values were found for cephalexin and cefixime (2 ug/mL). In this in vitro study, sensitivity to cephalothin was indicative of cephalexin susceptibility, although there were marked differences in MICs. Cephalothin susceptibility was not indicative of susceptibility to all tested cephalosporins, nor was there a clear trend in susceptibility based on cephalosporin generation.