Effect of an ear cleaner instillation containing lipacids in a model of re-acidification of the external auditory canal in dogs.

BACKGROUND: In humans, the acidic pH of the ear canal plays a protective role against infection and a change towards alkalinity of the external auditory canal (EAC) is a local factor in the progression of acute to chronic otitis externa (OE). The use of acidic preparations alone for treatment of OE without concurrent antibiotic use is well-documented in humans. In dogs, only one study has investigated the EAC pH in healthy dogs and in dogs with OE, and investigations to understand the role of EAC pH in the pathogenesis of canine OE are lacking. HYPOTHESIS/OBJECTIVES: To obtain physiological EAC pH values in beagle dogs. To develop a model of re-acidification of the EAC in dogs and to investigate how an acidic solution may accelerate the return to a physiological pH. ANIMALS: Ten healthy beagle dogs in a laboratory setting. MATERIALS AND METHODS: A model of re-acidification of the EAC was developed by instillation of a pH 10.1 phosphate-buffered saline (PBS) solution and the subsequent acidic effect of an ear cleaner containing lipacids was evaluated in this model. RESULTS: Mean physiological EAC pH was 6.12 (± 0.36). EAC re-acidification took up to 9 h in this model. Mean pH values dropped immediately to 6.38 (± 0.27) on ears treated with an acidic ear cleaner. No abrupt drop was observed of the mean pH values for the control ears. CONCLUSION AND CLINICAL IMPORTANCE: This study confirms that physiological EAC pH in dogs is acidic. This model of re-acidification of the EAC pH allows investigations on acidic properties of topical ear products in healthy ears.

Contexte - Chez l'homme, le pH acide du conduit auditif joue un rôle protecteur contre l'infection et l'évolution vers l'alcalinité du conduit auditif externe (CAE) et est un facteur local de progression de l'otite externe (OE) aiguë à chronique. L'utilisation de préparations acides seules pour le traitement de l'OE sans utilisation concomitante d'antibiotiques est bien documentée chez l'homme. Chez les chiens, une seule étude a étudié le pH du CAE chez les chiens en bonne santé et chez les chiens atteints d'OE, et les recherches pour comprendre le rôle du pH du CAE dans la pathogenèse de l'OE canine font défaut. Hypothèses/objectifs - Obtenir des valeurs physiologiques de pH du CAE chez des chiens beagle. Développer un modèle de réacidification du CAE chez le chien et étudier comment une solution acide peut accélérer le retour à un pH physiologique. Animaux - Dix chiens beagle de laboratoire en bonne santé. Matériels et méthodes - Un modèle de réacidification du CAE a été développé par instillation d'une solution saline tamponnée (PBS) à pH 10,1 et l'effet acide ultérieur d'un nettoyant pour oreilles contenant des lipacides a été évalué dans ce modèle. Résultats - Le pH physiologique moyen du CAE était de 6,12 (± 0,36). La réacidification du CAE a pris jusqu'à 9 h dans ce modèle. Les valeurs moyennes du pH chutent immédiatement à 6,38 (± 0,27) sur les oreilles traitées avec un nettoyant auriculaire acide. Aucune chute brutale n'a été observée des valeurs moyennes de pH pour les oreilles témoins. Conclusion et importance clinique - Cette étude confirme que le pH physiologique du CAE chez le chien est acide. Ce modèle de réacidification du pH du CAE permet des investigations sur les propriétés acides des produits topiques auriculaires dans des oreilles saines.

Introducción; en humanos, el pH ácido del canal auditivo juega un papel protector contra la infección y un cambio hacia la alcalinidad del canal auditivo externo (EAC) es un factor local en la progresión de la otitis externa (OE) aguda a crónica. El uso de preparaciones ácidas solas para el tratamiento de la OE sin el uso concomitante de antibióticos está bien documentado en humanos. En perros, solo un estudio ha investigado el pH de EAC en perros sanos y en perros con OE, y faltan investigaciones para comprender el papel del pH de EAC en la patogenia de la OE canina. Hipótesis/objetivos - Obtener valores de pH fisiológico de EAC en perros beagle. Desarrollar un modelo de reacidificación del EAC en perros e investigar cómo una solución ácida puede acelerar el retorno a un pH fisiológico. Animales- diez perros beagle sanos en un laboratorio. Materiales y métodos- se desarrolló un modelo de reacidificación del EAC mediante la instilación de una solución salina tamponada con fosfato (PBS) de pH 10,1 y se evaluó en este modelo el efecto ácido subsiguiente de un limpiador de oídos que contenía lípidos. Resultados - El pH fisiológico medio del EAC fue de 6,12 (± 0,36). La reacidificación de EAC tomó hasta 9 h en este modelo. Los valores medios de pH cayeron inmediatamente a 6,38 (± 0,27) en los oídos tratados con un limpiador de oídos ácido. No se observó una caída abrupta de los valores medios de pH para los oíds de control. Conclusión e importancia clínica- este estudio confirma que el pH fisiológico de EAC en perros es ácido. Este modelo de reacidificación del pH de EAC permite realizar investigaciones sobre las propiedades ácidas de los productos tópicos para el oído en oídos sanos.

Contexto - Em humanos, o pH ácido do conduto auditivo exerce uma grande função protetora contra infecções e a alcalinização do conduto auditivo externo (CAE) é um fator local de progressão de otite externa (OE) aguda para crônica. A utilização unicamente de formulações ácidas para o tratamento de OE sem a utilização concomitante de antibióticos é bem documentada em humanos. Em cães, apenas um estudo investigou o pH do CAE em cães saudáveis com OE, e são escassas as pesquisas investigando o papel do pH do CAE na patogênese da OE. Hipótese/objetivos - Se obter os valores fisiológicos do pH dos CAEs de cães Beagle. Desenvolver um modelo de re-acidificação do CAE em cães e investigar como uma solução ácida pode acelerar o retorno ao pH fisiológico original. Animais - Dez cães Beagle saudáveis de laboratório. Materiais e Métodos - Um modelo de re-acidificação do CAE foi desenvolvido por instilação de solução salina tamponada com fosfato (PBS) com um pH 10,1 e o efeito acidificante subsequente de um limpador de ouvido contendo ácidos lipídicos foi avaliado neste modelo. Resultados - O pH fisiológico médio do CAE foi de 6,12 (± 0,36). A re-acidificação do CAE levou até 9h neste modelo. Os valores médios de pH caíram imediatamente para 6,38 (± 0,27) nas orelhas tratadas com um limpador otológico ácido. Não foi observada queda abrupta dos valores médios de pH para as orelhas controle. Conclusão e importância clínica - Este estudo confirmou que o pH fisiológico do CAE de cães é ácido. Este modelo de re-acidificação do pH do CAE permite investigações sobre as propriedades acidificantes de produtos otológicos tópicos para orelhas saudáveis.

Extra-auricular lesions of proliferative and necrotizing otitis externa in three kittens.

BACKGROUND: Proliferative and necrotising otitis externa (PNOE) is a rare disorder in cats with poorly understood pathogenesis. Extra-auricular (EA) lesions recently have been mentioned in a textbook and in one case report. OBJECTIVES: To describe EA lesions associated with PNOE in three kittens. ANIMALS: A 6-month-old female domestic short hair (DSH) cat (Case 1), an 8-month-old female DSH cat (Case 2) and a 5-month-old female DSH cat (Case 3). METHODS AND RESULTS: All cases exhibited classical lesions of PNOE associated with EA lesions, generalised (cases 1 and 3) or limited to eyelids (Case 2). Lesions were characterised by thick, adherent, hyperkeratotic papules coalescing to plaques and attempts to remove the hyperkeratotic plaques resulted in erosions. Histopathological examinations revealed classical features of PNOE: severe acanthosis associated with a marked lymphocytic exocytosis, satellitosis and apoptotic keratinocytes at all levels of the epidermis and the outer root sheath of hair follicles. Cases 2 and 3 resolved spontaneously. Case 1 remained stable with topical tacrolimus and oral prednisolone after a short course of ciclosporin. CONCLUSIONS AND CLINICAL IMPORTANCE: This report describes EA lesions of PNOE in three kittens. Such lesions may be underdiagnosed, and this report emphasises the role of a thorough clinical inspection in PNOE cases.

A moisturizer formulated with glycerol and propylene glycol accelerates the recovery of skin barrier function after experimental disruption in dogs.

BACKGROUND: Moisturizers are foundational therapies for human atopic dermatitis. In veterinary medicine, the use of moisturizers has been recommended by an expert committee to alleviate skin dryness that would occur, for example, in canine atopic dermatitis (cAD). However, little is known regarding the effects of moisturizers on the skin barrier. HYPOTHESIS/OBJECTIVES: To investigate the effects of a moisturizer on skin barrier recovery in a canine model of chronic mechanical barrier disruption. ANIMALS: Six healthy beagle dogs maintained in a laboratory setting. METHODS AND MATERIALS: A model of chronic skin barrier disruption was simulated by tape stripping on both sides of the thorax. The moisturizer then was applied twice daily for one week to one side of the thorax, while the other hemithorax was left untreated. The effects were evaluated by measurement of transepidermal water loss (TEWL) at various times during skin barrier recovery, and by histological assessment of the disrupted skin one week after moisturizer application. RESULTS: Overall, TEWL was reduced, epidermal thickness was lower, stratum corneum thickness was greater and the intensity of the dermal inflammatory infiltrate was reduced for treated sites. CONCLUSIONS AND CLINICAL IMPORTANCE: These results suggest a potential benefit of the moisturizer for improving skin barrier function, which is frequently altered in chronic inflammatory dermatoses such as cAD.

Long-term successful treatment of a donkey with cutaneous lupus erythematous with methotrexate.

Cutaneous lupus erythematosus (CLE) is a rare immune-mediated dermatitis. To the best of the authors' knowledge it has not been described in donkeys. A 5-year-old male neutered donkey, living in south-east France, was diagnosed with CLE. Clinical signs included generalized symmetrical areas of alopecia, erythema, crusting and scales. Diagnostic tests included examination of skin biopsy samples by histopathological and immunohistochemical analysis which demonstrated an interface dermatitis with CD8+ T cells. The skin condition was successfully treated initially with glucocorticoids and methotrexate; successful long-term maintenance was associated with administration of methotrexate.

Le lupus cutané érythémateux (CLE) est une dermatite à médiation immune rare. A la connaissance des auteurs, il n'a pas été décrit chez le singe. Un singe mâle castré de 5 ans, vivant dans le sud-est de la France a été diagnostiqué avec CLE. Les signes cliniques incluaient des zones symétriques généralisées d'alopécie, d'érythème, de croûtes et de pellicules. Les tests diagnostics comprenaient un examen histopathologique et immunohistochimique de biopsies cutanées qui ont révélé une dermatite d'interface avec cellules T CD8+. La dermatose a été traitée avec succès initialement avec des corticoïdes et du méthotrexate; un traitement efficace au long cours a été associé avec l'administration de méthotrexate.

El lupus eritematoso cutáneo (CLE) es una rara dermatitis inmunomediada. A entender de los autores, esta enfermedad no se ha descrito en burros. Un burro castrado macho de 5 años de edad, que vive en el sureste de Francia fue diagnosticado con CLE. Los signos clínicos incluyeron áreas simétricas generalizadas de alopecia, eritema, costras y escamas. Las pruebas de diagnóstico incluyeron el examen de muestras de biopsia de piel mediante análisis histopatológico e inmunohistoquímico que demostró una dermatitis de interfase con células T CD8+. La condición de la piel se trató con éxito inicialmente con glucocorticoides y metotrexato; el control exitoso a largo plazo de la enfermedad se obtuvo con la administración de metotrexato.

O lúpus eritematoso cutâneo (LEC) é uma dermatite imunomediada rara. De acordo com os conhecimentos do autor, a doença ainda não foi descrita em jumentos. Um jumento macho castrado de cinco anos de idade, habitante do sul da França, foi diagnosticado com LEC. Os sinais clínicos incluíram alopecia, eritema, crostas e descamação generalizadas e simétricas. Os testes diagnósticos utilizados foram avaliação de amostras de biópsia por análise histopatológica e imunohistoquímica, que demonstraram dermatite de interface com células T CD8+. A dermatopatia foi tratada satisfatoriamente inicialmente com glicocorticoide e metotrexato; a manutenção satisfatória a longo prazo foi associada à administração de metotrexato.

Pharmacokinetics of low-dose methotrexate in horses.

This study aimed to investigate both the pharmacokinetic behavior and tolerance of methotrexate (MTX) in horses to design a specific dosing regimen as a new immunomodulatory drug for long-term treatment. To determine the primary plasma pharmacokinetic variables after single intravenous, subcutaneous or oral administration, six horses were administered 0.3 mg/kg MTX in a crossover design study. After a 10-week washout, MTX was administered subcutaneously to three of the six previously treated horses at a dose of 0.3 mg/kg once per week for 3 months. In both studies, MTX and metabolite concentrations were measured using LC-MS/MS. The absolute bioavailability of MTX was 73% following subcutaneous administration but less than 1% following oral administration. The plasma clearance was 1.54 ml min-1  kg-1 (extraction ratio = 2%). After 24 hr, plasma concentrations were below the LOQ. No adverse effects were noted except for a moderate reversible elevation in liver enzymes (GLDH). With regards to the main metabolites of MTX, very low concentrations of 7-hydroxy-MTX were found, whereas polyglutamated forms (mainly short chains) were found in red blood cells. A subcutaneous dose of 0.2 mg kg-1  week-1 may be safe and relevant in horses, although this has yet to be clinically confirmed.

Equine pastern vasculitis in a horse associated with a multidrug-resistant Pseudomonas aeruginosa isolate.

BACKGROUND: Equine pastern vasculitis is an uncommon disorder in horses. Underlying causes are difficult to assess, especially bacterial infections. CLINICAL SUMMARY: A 13-year-old French saddle gelding horse presented for evaluation of a six weeks history of pastern dermatitis. Histopathological examination of skin biopsy samples revealed small vessel vasculitis. A pure growth of a multidrug-resistant Pseudomonas aeruginosa (MRPA) was obtained from a deep skin biopsy. Clinical remission was observed after a six week course of enrofloxacin and lesions did not recur. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first report of a pastern vasculitis associated with MRPA and successfully treated with a six week course of enrofloxacin.

Granulomatous mural folliculitis in a dog treated with ciclosporin and methotrexate.

BACKGROUND: Canine granulomatous mural folliculitis is a very rare cause of scarring alopecia with unknown pathogenesis. HYPOTHESIS/OBJECTIVES: To report a case of granulomatous mural folliculitis in a dog treated with ciclosporin (Cs) and methotrexate (MTX). ANIMAL: A 13-year-old spayed female Pyrenean shepherd dog with a one month history of scarring alopecia. METHODS AND RESULTS: Histopathological examination revealed a granulomatous and lymphocytic mural and necrotizing folliculitis and furunculosis. Immunochemistry, using antibodies for CD3, CD204, CD206, IBA-1 and CD208, revealed that CD3+ lymphocytes were infiltrating the outer root sheath along with IBA-1+ or CD204+ cells. Ciclosporin (5 mg/kg once daily) and MTX (0.25 mg/kg once weekly then 0.5 mg/kg once weekly) were initiated simultaneously, and Cs was stopped after stabilization of the lesions. The dog's skin disease was stable for six months. CONCLUSIONS AND CLINICAL IMPORTANCE: To the best of the authors' knowledge, this is the first report of the long-term management of a granulomatous mural folliculitis in a dog. Ciclosporin and MTX appeared to be an effective treatment option. Additional treated cases are needed to assess the effectiveness of MTX in canine immune-mediated diseases.