Sébastien Perrot

Null alleles of ABCG2 encoding the breast cancer resistance protein define the new blood group system Junior.

The breast cancer resistance protein, also known as ABCG2, is one of the most highly studied ATP-binding cassette (ABC) transporters because of its ability to confer multidrug resistance. The lack of information on the physiological role of ABCG2 in humans severely limits cancer chemotherapeutic approaches targeting this transporter. We report here that ABCG2 comprises the molecular basis of a new blood group system (Junior, Jr) and that individuals of the Jr(a−) blood type have inherited two null alleles of ABCG2. We identified five frameshift and three nonsense mutations in ABCG2. We also show that the prevalence of the Jr(a−) blood type in the Japanese and European Gypsy populations is related to the p.Gln126* and p.Arg236* protein alterations, respectively. The identification of ABCG2−/− (Jr(a−)) individuals who appear phenotypically normal is an essential step toward targeting ABCG2 in cancer and also in understanding the physiological and pharmacological roles of this promiscuous transporter in humans.

Association between passive smoking and atopic dermatitis in dogs

Onset of atopic dermatitis and occurrence of related skin lesions are influenced by various environmental factors in humans, and companion animals. Several studies have demonstrated an association between passive smoking and the development of atopic dermatitis in children. This association has never been investigated in the dog to our knowledge. We enrolled 161 dogs seen at dermatology and vaccination consultations over a six-month period for this study. Dog owners were asked to complete a questionnaire, to evaluate the exposure of the dog to tobacco smoke. The atopic or non-atopic status of the dog was assessed on the basis of Favrots criteria (history, clinical examination and cutaneous cytology for Malassezia). Analysis of the data for the 161 dogs enrolled revealed a significant association between high levels of passive exposure to tobacco smoke (cigarette consumption divided by the area of the home) and the presence of atopic dermatitis in the dogs (OR, 4.38; 95% CI, 1.10-17.44; p=0.03; NNH (number needed to harm) 3, 95% CI 2-52). The prevalence of atopic dermatitis showed a slight, but non-significant association with breed predisposition. Dogs with high levels of exposure to tobacco smoke may have a higher risk of atopic dermatitis than non-exposed dogs.

Amlodipine: One of the main anti-hypertensive drugs in veterinary therapeutics

Amlodipine is a dihydropyridine compound and belongs to the pharmacological family of calcium channel blockers. It is one of the main treatments of systemic arterial hypertension in cats and its validity has been confirmed in several reports. Its beneficial effect on the peripheral and coronary vascular bed is due to immediate vasodilation and to a delayed anti-hypertrophic action. The aim of the present review is to highlight the clinically-relevant characteristics of amlodipine, especially regarding its mechanism of action, and to present the main clinical reports supporting its interest in veterinary cardiology.

Ex-Vivo percutaneous absorption of enrofloxacin: Comparison of LMOG organogel vs. pentravan cream.

The objective of this study was to investigate the percutaneous absorption of enrofloxacin from two base formulations, Pentravan cream and LMOG organogel. Ex-vivo experiments were carried out on pig ear skin. The percutaneous permeation through pig skin of two formulations containing 5 wt% of enrofloxacin was measured and compared using Franz diffusion cells. At appropriate intervals up to 120 h, diffusion samples were taken and analyzed using HPLC assays. Permeation profiles were established and the parameters Tlag and flux values were calculated. In this ex-vivo study, the flux values were 0.35 μgcm(-2)h(-1) for Pentravan and 1.22 μgcm(-2)h(-1) for LMOG organogel, corresponding respectively to 7.9 % and 29.3 % of enrofloxacin absorbed after 120 h by these formulations. The lag time (T lag) of Pentravan and organogel were 6.32 and 0.015 h respectively. The absorption time to reach the antibiotic concentration of enrofloxacin (2 μgmL(-1)) in the receptor was 60 h with Pentravan and 30 h with the organogel, suggesting more effective treatment by the latter. Enrofloxacin contained in organogel could be absorbed through pig ear skin 3.7 times greater than that in Pentravan (commercial formulation). This study demonstrates the perspective of organogel formulations as potential drug delivery systems.

PrPc deficiency and dasatinib protect mouse intestines against radiation injury by inhibiting of c-Src

BACKGROUND & AIM Despite extensive study of the contribution of cell death and apoptosis to radiation-induced acute intestinal injury, our knowledge of the signaling mechanisms involved in epithelial barrier dysfunction remains inadequate. Because PrP(c) plays a key role in intestinal homeostasis by renewing epithelia, we sought to study its role in epithelial barrier function after irradiation. DESIGN Histology, morphometry and plasma FD-4 levels were used to examine ileal architecture, wound healing, and intestinal leakage in PrP(c)-deficient (KO) and wild-type (WT) mice after total-body irradiation. Impairment of the PrP(c) Src pathway after irradiation was explored by immunofluorescence and confocal microscopy, with Caco-2/Tc7 cells. Lastly, dasatinib treatment was used to switch off the Src pathway in vitro and in vivo. RESULTS The decrease in radiation-induced lethality, improved intestinal wound healing, and reduced intestinal leakage promoted by PrP(c) deficiency demonstrate its involvement in acute intestinal damage. Irradiation of Cacao2/Tc7 cells induced PrP(c) to target the nuclei associated with Src activation. Finally, the protective effect triggered by dasatinib confirmed Src involvement in radiation-induced acute intestinal toxicity. CONCLUSION Our data are the first to show a role for the PrP(c)-Src pathway in acute intestinal response to radiation injury and offer a novel therapeutic opportunity.

Efficacy of a 2% climbazole shampoo for reducing Malassezia population sizes on the skin of naturally infected dogs

OBJECTIVE OF THE STUDY Shampoo therapy is often recommended for the control of Malassezia overgrowth in dogs. The aim of this study was to evaluate the in vivo activity of a 2% climbazole shampoo against Malassezia pachydermatis yeasts in naturally infected dogs. ANIMALS Eleven research colony Beagles were used. MATERIALS AND METHODS The dogs were distributed randomly into two groups: group A (n=6) and group B (n=5). Group A dogs were washed with a 2% climbazole shampoo, while group B dogs were treated with a physiological shampoo base. The shampoos were applied once weekly for two weeks. The population size of Malassezia yeasts on skin was determined by fungal culture through modified Dixons medium contact plates pressed on left concave pinna, axillae, groins, perianal area before and after shampoo application. Samples collected were compared by Wilcoxon rank sum test. RESULTS Samples collected after 2% climbazole shampoo application showed a significant and rapid reduction of Malassezia population sizes. One hour after the first climbazole shampoo application, Malassezia reduction was already statistically significant and 15 days after the second climbazole shampoo, Malassezia population sizes were still significantly decreased. No significant reduction of Malassezia population sizes was observed in group B dogs. CONCLUSION The application of a 2% climbazole shampoo significantly reduced Malassezia population sizes on the skin of naturally infected dogs. Application of 2% climbazole shampoo may be useful for the control of Malassezia overgrowth and it may be also proposed as prevention when recurrences are frequent.

Assessment of ocular discomfort caused by 5 shampoos using the Slug Mucosal Irritation test

Assessment of ocular discomfort caused by veterinary care products is less legitimately regulated than that caused by human care products. The Slug Mucosal Irritation (SMI) assay was adapted to evaluate canine hygiene shampoos to predict ocular discomfort. Experiments were performed using four commercial canine shampoos, a baby care product, and two controls (ArtTear® and BAC1%). Groups of 3 slugs were tested with 5% dilution of the 7 test substances. The negative control (ArtTear®) was the best tolerated. The baby care product Mixa bébé as well as Douxo Entretien Démêlant and Phlox Shampooing Entretien were classified to cause mild ocular discomfort. Together with the positive control (BAC 1%), Shampooing Physiologique Virbac and Physiovet Shampooing were considered to cause severe ocular discomfort. Different intensities of ocular discomfort were measured for veterinary care products. The SMI model was considered as a reproducible and adaptable evaluation method for screening veterinary care products causing ocular discomfort.

Efficacy of guar gum-based ronidazole capsules as a treatment for Tritrichomonas foetus infection in cats.

Objectives The aims of the study were to determine the in vitro drug release of guar gum-coated capsules of ronidazole, and to evaluate the pharmacokinetics and efficacy of this formulation for the treatment of cats naturally infected with Tritrichomonas foetus. Methods The pharmacokinetics of ronidazole were evaluated in five healthy cats and five cats infected with T foetus. In a second step, the clinical efficacy of these capsules was evaluated by a controlled, randomised, double-blind clinical trial performed in 47 infected cats from French catteries. In this study, cats were randomly allocated to either the ronidazole treatment group (n = 25) or a placebo group (n = 22). Ronidazole (30 mg/kg) q24h for 14 days was administered to the treated cats. After 14 days of treatment, the presence of T foetus was tested by conventional PCR assay. Results In the pharmacokinetic study, a delayed peak plasma concentration was observed in healthy and infected cats, with no significant difference between these two groups (mean geometric mean of 9 h for time to maximum plasma concentration [Tmax], 21.6 µg/ml for time to maximum plasma concentration [Cmax] and 467.4 μg/h/ml for the area under the curve [AUC] in healthy cats; and 9.4 h for Tmax, 17.1 µg/ml for Cmax and 481 μg/h/ml for AUC in infected cats). In the clinical trial, T foetus was detected in 16% of cats from the treated group and 82% of cats from the placebo group at the end of the study (P <0.001). No clinical signs of adverse drug reactions were observed. Conclusions and relevance Oral administration of guar gum-coated capsules of ronidazole at a dose of 30 mg/kg once daily for 14 days delays the peak plasma concentration and eradicates infection in most cases.

Detection of Enrofloxacin After Single-Dose Percutaneous Administration in Python regius, Boa constrictor imperator, and Acrantophis dumerili

Abstract In this study, the blood concentrations of enrofloxacin administered transdermally to 3 different reptilian species, Python regius, Acrantophis dumerili, and Boa constrictor imperator, at 50 mg/kg was determined. The formulation used was a transdermal commercial vehicle, Pentravan cream, a hydrophilic base emulsion that uses the liposomal technique to penetrate the skin. The enrofloxacin was incorporated at 5 wt% in the Pentravan cream, and the plasma concentrations of enrofloxacin and its metabolite ciprofloxacin were measured using high‐performance liquid chromatography. The results showed that the detected amounts of enrofloxacin and ciprofloxacin (0.33 and <0.15 &mgr;g/mL, respectively) were below the limit of quantification. Enrofloxacin was detected in P. regius and B. constrictor, while ciprofloxacin was detected only in A. dumerili. Although the values were unquantifiable, this study confirms the absorption of enrofloxacin. Therefore, these findings suggests that enrofloxacin may be a candidate for treatment using the transdermal route in certain reptile species.

Canine Atopic Dermatitis Diagnostic Criteria: Evaluation of Four Sets of Published Criteria among Veterinary Students

Canine atopic dermatitis (cAD) is a major teaching point as its diagnosis and treatment are difficult. During 11 weeks, 140 dogs and students (third, fourth, and fifth years) were recruited and paired. One of the four lists of diagnostic criteria was randomly attributed to each student. Concordance results, calculated with Cohens kappa, ranged from slight (κ=0.07) to moderate (κ=0.53). Favrots diagnostic criteria received the best results. It has been observed that results are improved with clinical experience. We observed that students often forgot that Favrots criteria apply only to pruritic dogs and that the fulfillment of the criteria allows only a suspicion, not a diagnosis, of cAD. Primary pruritus and corticosteroid-responsive pruritus were often misunderstood.