Pharmacokinetic evaluation of enrofloxacin administered orally to healthy dogs.

Enrofloxacin was administered orally to 6 healthy dogs at dosages of approximately 2.75, 5.5, and 11 mg/kg of body weight, every 12 hours for 4 days, with a 4-week interval between dosage regimens. Serum and tissue cage fluid (TCF) concentrations of enrofloxacin were measured after the first and seventh treatments. The mean peak serum concentration occurred between 1 and 2.5 hours after dosing. Peak serum concentrations increased with increases in dosage. For each dosage regimen, there was an accumulation of enrofloxacin between the first and seventh treatment, as demonstrated by a significant (P = 0.001) increase in peak serum concentrations. The serum elimination half-life increased from 3.39 hours for the 2.75 mg/kg dosage to 4.94 hours for the 11 mg/kg dosage. Enrofloxacin accumulated slowly into TCF, with peak concentrations being approximately 58% of those of serum. The time of peak TCF concentrations occurred between 3.8 hours and 5.9 hours after drug administration, depending on the dosage and whether it was after single or multiple administrations. Compared with serum concentrations (area under the curve TCF/area under the curve serum), the percentage of enrofloxacin penetration into TCF was 85% at a dosage of 2.75 mg/kg, 83% at a dosage of 5.5 mg/kg, and 88% at a dosage of 11 mg/kg. All 3 dosage regimens of enrofloxacin induced continuous serum and TCF concentrations greater than the minimal concentration required to inhibit 90% (MIC90) of the aerobic and facultative anaerobic clinical isolates tested, except Pseudomonas aeruginosa.(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibitory effects of interleukin-10 plasmid DNA on the development of atopic dermatitis-like skin lesions in NC/Nga mice

Interleukin (IL)-10 exerts potent anti-inflammatory effects by suppression of both T-help (Th) 1 and Th2 cells. Previous studies have reported that IL-10 can ameliorate various inflammatory disorders. The present study was performed to examine whether IL-10 plasmid DNA could suppress development of atopic dermatitis (AD)-like skin lesions in NC/Nga mice, as an initial step towards the development of an appliance for use in dogs with AD. Intradermal injection of IL-10 plasmid DNA markedly inhibited the development of AD-like skin lesions, as evidenced by a marked decrease in skin symptoms and reduced inflammation within the skin lesions. Efficacy was confirmed by significant decreases in eosinophil ratio and serum IgE concentration, and a reduction in the number of Staphylococcus aureus recovered from the ear. Moreover, relative mRNA expression levels of IL-4 and interferon-γ in the skin lesions of mice injected with IL-10 plasmid DNA were also decreased compared with those of control mice. Of note, higher serum IL-10 levels in mice injected with IL-10 plasmid DNA were maintained compared with those in control mice. Taken together, the results indicate that IL-10 plasmid DNA can suppress the development of AD-like skin lesions by suppressing both Th1 and Th2 cell responses. Beneficial effects of IL-10 plasmid DNA may be expected in dogs with AD.     

Atopic NC/Nga mice as a model for allergic asthma: cytokine profiles and eosinophil productivity of bone marrow

In previous study, NC/Nga mice with experimentally induced asthma showed severe eosinophilia. To explore the mechanism, profiles of representative cytokines interleukin (IL)-4, IL-5, and interferon (IFN)-gamma were examined in bronchoalveolar lavage fluid. The level of only IFN-gamma was lower in NC/Nga mice than control BALB/c mice. Furthermore, bone marrow cell culture system under the presence of eosinopoietic cytokines, which induce the differentiation of progenitor cells into mature eosinophils, showed that a larger number of eosinophils differentiated from NC/Nga mice derived bone marrow cells than from control BALB/c mice. These results may imply the possibility that severe eosinophilia in the NC/Nga mice are attributable to lower production of IFN-gamma and higher eosinophil productivity of bone marrow cells.     

Fermented Maesil (Prunus mume) with probiotics inhibits development of atopic dermatitis‐like skin lesions in NC/Nga mice

Maesil (Prunus mume Siebold & Zucc.), a potential source of free radical scavengers and inhibitor of pro‐inflammatory mediators, is used in traditional Korean medical preparations as a remedy for skin disorders as have probiotics. The action of a probiotic fermented Maesil preparation on the development of atopic dermatitis (AD)‐like skin lesions was determined in a NC/Nga mouse model as an initial step towards the development of a therapeutic feed supplement for use in dogs. Continuous ingestion of the experimental feed markedly inhibited the development of the AD‐like skin lesions, as evidenced by a marked decrease in skin signs and reduced inflammation within the skin lesions. Efficacy was confirmed by significant decreases in eosinophil ratio and serum IgE concentration, and a reduction in the number of Staphylococcus aureus recovered from the ear. Relative mRNA expression levels of IL‐4, interferon‐γ and tumour necrosis factor‐α in the spleens of the experimental animals were also decreased and there was an increased serum concentration of IL‐10 with a concurrent decreased IL‐4 concentration in comparison to a control group. Taken together, the results indicate that some component(s) of fermented Maesil have the ability to suppress the development of AD‐like skin lesions, possibly by stimulation of IL‐10. Beneficial effects of fermented Maesil may thus be expected in dogs with AD, although this and the nature of the active pathway remain to be explored.     

Clinical and histopathological findings in pustular psoriaform dermatitis (pityriasis rosea) in pigs

Three cases of pustular psoriaform dermatitis (pityriasis rosea) in pigs were clinically and histopathologically examined. Grossly, the affected skin was characterized by multiple, circumscribed lesions. Three pigs were the descendants derived from the same Landrace boar. Skin lesions expanded centrifugally to became ring-shaped plaques. There were no abnormal values in hematological and serum biochemical profiles. Histopathologically, the epidermis showed remarkable thickening. The dermal lesions were characterized by a prominent component of superficial and deep perivascular infiltration of eosinophils. Dilatation of microvasculature was accompanied with congested vessels. These results revealed that the etiology of pustular psoriaform dermatitis in pigs was associated with a hereditary predisposition derived from the specific boars. This dermatosis is histopathologically characterized by microcirculatory disturbances with infiltration of abundant eosinophils.     

Characterisation of major and minor Dermatophagoides allergens in canine atopic dermatitis

Atopic dermatitis is a well-recognised chronic inflammatory skin disease of humans and dogs. Most atopic dogs are sensitised to Dermatophagoides mites. The aim of this study was to characterise allergens in different Dermatophagoides species using polyclonal and monoclonal antibodies to canine IgE. Western blots were prepared from crude extracts of D farinae, D pteronyssinus and D microceras, and purified group 1 and 2 allergens under reducing and non-reducing conditions. They were probed with sera from atopic (n = 33) and healthy (n = 27) dogs. There was no significant difference in the sensitivity or specificity between the polyclonal and monoclonal sera in detecting Dermatophagoides -specific IgE. Major allergens common to both D farinae and D pteronyssinus were detected at 97-98 kDa, 103-104 kDa and 134-139 kDa on both reducing and non-reducing blots. Major allergens at 84-85 kDa, 65-69 kDa and 44-45 kDa were only recognised on reducing blots, suggesting that these are fragments of the larger allergens. Only a few sera recognised group 1 or 2 allergens on blots of crude extracts or purified allergens. These results confirm that, in atopic dogs, high molecular weight allergens are the most important Dermatophagoides allergens, rather than the low molecular weight group 1 and 2 proteins.     

表达EDA-EmIMP1的重组枯草芽孢杆菌的制备及其免疫效果评价

枯草芽孢杆菌可以作为外源蛋白的表达系统,其作为重组蛋白的递呈载体具有很大优势,而纤维连接蛋白外域A(EDA)是一种能够提高目标蛋白抗原性的佐剂。为增强巨型艾美耳球虫的免疫相关蛋白1(IMP1)的抗原性,本研究从已构建的重组质粒中扩增EDA-EmIMP1和EmIMP1基因片段,并构建重组表达质粒pHT01-EDA-EmIMP1和pHT01-EmIMP1,将获得的重组质粒转化枯草芽孢杆菌感受态细胞,制备的重组枯草芽孢杆菌鉴定正确后增殖培养。将实验鸡分为5组,分别是:EDA组(免疫pHT01-EDA-EmIMP1重组枯草芽孢杆菌)、EmIMP1组(免疫pHT01-EmIMP1重组枯草芽孢杆菌)、枯草芽孢杆菌组、空白组(PBS)和攻虫对照组。每组鸡口服相应菌液(0.3mL1010cfu/mL菌液/只)进行免疫,每隔2周免疫1次,共免疫3次,每次免疫2周后采血。三免2周后攻虫。采用ELISA方法检测各组鸡血清中EmIMP1的抗体滴度以及细胞因子IL-10和IL-4的含量;并对攻虫后各组鸡的增重、肠道病变计分以及卵囊排出量进行计算。结果显示:制备的重组枯草芽孢杆菌可以表达目的蛋白,蛋白大小为70ku。ELISA检测结果显示,EDA组的抗体效价最高,约为1∶3200;三免EDA组的IL-10和IL-4的含量均显著高于其它组(p<0.05);EDA组的卵囊排出量显著低于其它组,而枯草芽孢杆菌组和EmIMP1组的卵囊排出量也均显著低于攻虫组(p<0.05);EDA组对肠道保护效果显著优于其它经过攻虫处理的组(p<0.05),而枯草芽孢杆菌组和EmIMP1组之间无显著差异;EDA组增重显著高于攻虫组和枯草芽孢杆菌组(p<0.05)。本研究证实枯草芽孢杆菌作为EmIMP1的抗原递呈载体可以有效提高免疫原性,其中EDA佐剂组的免疫效果最好。     

Atopic NC/Nga mice as a model for allergic asthma: severe allergic responses by single intranasal challenge with protein antigen

Since certain characters of allergic asthma are common with other allergic disorders like atopic dermatitis, the possible relationship in etiology is expected. Herein, we investigated whether NC/Nga mice, an inherent animal model for human atopic dermatitis, are inclined to allergic asthma. A single intranasal challenge of NC/Nga mice immunized with ovalbumin (OVA) resulted in an increase in plasma levels of OVA-specific IgE, and typical pathological aspects of allergic asthma characterized by infiltration of numerous eosinophils, mucus hyper production of bronchial epithelial cells. Moreover, airway hyperresponsiveness to inhaled acetylcholine and marked enhancement of airway resistance after the challenge were observed as compared to control BALB/c mice. Delayed expression of mRNA of eosinophil active chemokines, interleukin-5, eotaxin, macrophage inflammatory protein-1alpha in concert with eosinophilia was determined in the lung of NC/Nga mice. These results suggest that asthmatic responses developed in NC/Nga mice challenged with OVA are very similar to human allergic asthma, and that NC/Nga mice are a useful model to elucidate various aspects of allergic asthma.     

Clinical, histopathological and therapeutic considerations in a flock of sheep with facial staphylococcal-associated dermatitis

In a flock of 290 sheep, a total of 20 ewes (6.9%) with an age range of 1.5-4 years, developed a nonpruritic dermatitis characterized by alopecia/hypotrichosis, erythema, hyperpigmentation, crusting, superficial ulcers, exudation and thickening of the skin that was localized mainly to the peri-ocular area. Frequent and massive feeding of swarming sucking flies on the lesional sites was witnessed. In every instance (n = 6), Staphylococcus aureus was cultured from the exudate and the aseptically obtained skin biopsy samples from both recurrent and new cases. The main predisposing factor was the presence of small troughs, which forced the sheep to compete for food. Intramuscular administration of cefalexin for 7 days resulted in the resolution of lesions over a 2-week period. No further cases or recurrences were seen over the 16-month follow-up period. The main histopathological feature of this skin disease was a superficial and deep, perivascular to interstitial eosinophilic and mononuclear dermatitis.     

Phase I and pharmacokinetic evaluation of the combination of orally administered docetaxel and cyclosporin A in tumor-bearing cats

Intravenously administered docetaxel (DT) is problematic in cats because of the requirement for premedication to ameliorate acute vehicle-induced hypersensitivity reactions. Previously we have revealed that therapeutic plasma concentrations of DT can be achieved in normal and tumor-bearing dogs when DT is administered PO in combination with oral cyclosporin A (CSA). The purpose of this study was to identify the maximally tolerated dosage and characterize the pharmacokinetic disposition of oral DT combined with CSA in cats with tumors. Eighteen tumor-bearing cats were enrolled in this phase I dose escalation and pharmacokinetic study. DT was administered by gavage with CSA (5 mg/kg) twice over a 3-week period. The starting dose of DT was 1.0 mg/kg. Based on the clinical toxicity profile, with gastrointestinal adverse effects and hematologic toxicity the maximal tolerated dose of oral DT was 1.75 mg/kg in combination with 5 mg/kg CSA. Additional studies are necessary to determine the efficacy of DT/CSA in cats with epithelial tumors.     

Phase I and pharmacokinetic evaluation of the combination of orally administered docetaxel and cyclosporin A in tumor-bearing dogs

OBJECTIVE: To determine the maximum tolerated dose and characterize the pharmacokinetic disposition of an orally administered combination of docetaxel and cyclosporin A (CSA) in dogs with tumors. ANIMALS: 16 client-owned dogs with metastatic or advanced-stage refractory tumors. PROCEDURES: An open-label, dose-escalation, single-dose, phase I study of docetaxel administered in combination with a fixed dose of CSA was conducted. Docetaxel (at doses of 1.5, 1.625, or 1.75 mg/kg) and CSA (5 mg/kg) were administered concurrently via gavage twice during a 3-week period. Plasma docetaxel concentrations were quantified by use of high-performance liquid chromatography, and pharmacokinetic disposition was characterized by use of noncompartmental analysis. Dogs' clinical signs and results of hematologic and biochemical analyses were monitored for evidence of toxicosis. RESULTS: No acute hypersensitivity reactions were observed after oral administration of docetaxel. Disposition of docetaxel was dose independent over the range evaluated, and pharmacokinetic variables were similar to those reported in previous studies involving healthy dogs, with the exception that values for clearance were significantly higher in the dogs reported here. The maximum tolerated dose of docetaxel was 1.625 mg/kg. Gastrointestinal signs of toxicosis were dose limiting. CONCLUSIONS AND CLINICAL RELEVANCE: The absence of myelosuppression suggested that the docetaxel-CSA combination may be administered more frequently than the schedule used. Further studies are warranted to evaluate combination treatment administered on a biweekly schedule in dogs with epithelial tumors.     

Pharmacodynamics and pharmacokinetics of orally administered bishydroxycoumarin in the goat

Eight goats, 2 nontreated controls and 6 treated, were used to study the pharmacodynamics and pharmacokinetics of bishydroxycoumarin. In 5 of the 6 treated goats, there was a significant relationship between prothrombin times and drug concentrations. Activated clotting times did not change with time in either the controls or the treated goats. Five of 6 treated goats reached a plateau of drug concentration after 24 to 36 hours. Lag times for onset of pharmacologic effect ranged from 12 to 24 hours. The one goat (No. 3) that did not respond in concert with the other 5 was extremely nervous and became anorectic during the period of indoor confinement.     

Pharmacokinetics of intravenously and orally administered pyrimethamine in horses.

Single-dose pharmacokinetic variables of pyrimethamine were studied in horses. Pyrimethamine (1 mg/kg of body weight) was administered IV and orally to 6 adult horses, and plasma samples were obtained at frequent intervals thereafter. Plasma pyrimethamine concentration was assayed by gas chromatography, and concentration-time data were analyzed, using a pharmacokinetic computer program. The IV and oral administration data were best described by 3-compartment and 1-compartment models, respectively. The median volume of distribution at steady state after IV administration was 1,521 ml/kg and the median elimination half-time was 12.06 hours. Mean plasma concentration after oral administration fluctuated between a maximal concentration of 0.18 microgram/ml and 0.09 microgram/ml (24 hours after dosing). Bioavailability after oral administration was 56%.     

Pharmacokinetics of orally administered pirfenidone in male and female beagles

Pirfenidone, a promising antifibrotic agent, was administered orally to dogs at 0, 40, 140, and 400 mg/kg/day. Serum was collected for pirfenidone assay at 0, 26 and 39 weeks of treatment. From the pirfenidone concentrations, pharmacokinetic parameters were determined for each dog at each treatment interval. The only significant differences because of gender were for concentration maxima. Unsurprisingly, there were many significant differences because of dose in concentration maximum and area under curve (AUC), and significant, positive linear correlations of both parameters with dose. There were few significant differences in time of maximal concentration and no correlation with dose. The mean +/- SE clearances were 1.99 +/- 0.13, 1.64 +/- 0.13 and 1.78 +/- 0.14 L/h/kg for doses of 40, 140, and 400 mg/kg, respectively, with no significant differences attributable to dose. There was an unexplained pattern in maximal concentration and AUC with regard to duration of treatment, with the parameters being highest at week 0, lowest at week 26, and intermediate at week 39. Clearance had the reverse pattern; time of maximal concentration had no pattern.     

Teratogenicity and embryotoxicity of orally administered fenchlorphos in blue foxes

Pregnant blue foxes (Alopex lagopus) were administered fenchlorphos (0-0-dimethyl-0-(2,4,5-trichlorophenyl) phos-phorothioate) orally at a dose of 100 mg/kg/day in different periods of gestation. The dose chosen represents the therapeutic dose for the treatment of parasitic lesions. At term the mean number of whelps were recorded, and they were killed and examined for external, visceral and skeletal malformations. Of 19 medicated vixens the mean number of live whelps at term was 1.2 per vixen versus 9.5 in the control group. There was an evident predominance of males in the medicated groups. Several malformations of the head were registered, among them incomplete ossification of the skull bones, cleft palate, hydrocephalus internus and externus. Minor malformations like extra ribs or missing ribs occurred in the medicated groups. Congenital alopecia, hypoplastic kidneys, and hydronephrosis were observed in all the whelps in 1 medicated group. No significant difference in total brain weight, cerebellum weight or the cerebellum-to-total-brain weight was observed.Histological examination of the cerebellum showed a narrowing or absence of the granular and the molecular layers of the cortical zone.Key words: teratogenicity, embryotoxicity, fenchí orphos, blue fox     

Pharmacokinetics of enrofloxacin administered intravenously and orally to foals

OBJECTIVE: To determine the pharmacokinetics of enrofloxacin administered IV and orally to foals. ANIMALS: 5 clinically normal foals. PROCEDURE: A 2-dose cross-over trial with IV and oral administration was performed. Enrofloxacin was administered once IV (5 mg/kg of body weight) to 1-week-old foals, followed by 1 oral administration (10 mg/kg) after a 7-day washout period. Blood samples were collected for 48 hours after the single dose IV and oral administrations and analyzed for plasma enrofloxacin and ciprofloxacin concentrations by use of high-performance liquid chromatography. RESULTS: For IV administration, mean +/- SD total area under the curve (AUC0-infinity) was 48.54 +/- 10.46 microg x h/ml, clearance was 103.72 +/- 0.06 ml/kg/h, half-life (t1/2beta) was 17.10 +/- 0.09 hours, and apparent volume of distribution was 2.49 +/- 0.43 L/kg. For oral administration, AUC0-infinity was 58.47 +/- 16.37 microg x h/ml, t1/2beta was 18.39 +/- 0.06 hours, maximum concentration (Cmax) was 2.12 +/- 00.51 microg/ml, time to Cmax was 2.20 +/- 2.17 hours, mean absorption time was 2.09 +/- 0.51 hours, and bioavailability was 42 +/- 0.42%. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with adult horses given 5 mg of enrofloxacin/kg IV, foals have higher AUC0-infinity, longer t1/2beta, and lower clearance. Concentration of ciprofloxacin was negligible. Using a target Cmax to minimum inhibitory concentration ratio of 1:8 to 1:10, computer modeling suggests that 2.5 to 10 mg of enrofloxacin/kg administered every 24 hours would be effective in foals, depending on minimum inhibitory concentration of the pathogen.     

Safety evaluation of orally administered afoxolaner and milbemycin oxime in eight‐week‐old dogs

The safety profile of afoxolaner (an isoxazoline molecule) when combined with milbemycin oxime (a macrocyclic lactone) was evaluated according to the regulatory requirements when administered six times orally in a soft chewable formulation at a dose of at least 1×, 3×, or 5× the maximum exposure dose in 8‐week‐old Beagle dogs. Thirty‐two healthy puppies (16 males and 16 females) were enrolled and allocated randomly to one of four treatment groups. Three doses were administered at 28‐day intervals (Days 0, 28, and 56), followed by three additional doses administered with 14‐day intervals (Days 84, 98, and 112). The study ended on Day 126. Treatment groups were as follows: Group 1: untreated, sham‐dosed control; Group 2: afoxolaner/milbemycin oxime chews administered at a dose of at least 5 and 1 mg/kg, respectively (1×); Group 3: afoxolaner/milbemycin oxime chews administered at a dose of at least 15 and 3 mg/kg, respectively (3); and Group 4: afoxolaner/milbemycin oxime chews administered at a dose of at least 25 and 5 mg/kg, respectively (5×). All dogs were examined for general health twice a day beginning on Day ‐14. Physical examinations, and blood collections for clinical pathology analysis and afoxolaner and milbemycin oxime plasma concentrations, were performed throughout the study. No afoxolaner/milbemycin oxime treatment‐related changes were observed in growth, physical variables, clinical pathology variables, or tissues examined histologically. No clinically relevant or statistically significant health abnormalities related to the administration of afoxolaner/milbemycin oxime were observed. No signs of macrocyclic lactone sensitivity were observed at any time during the study. Vomiting and diarrhea were observed sporadically across all groups including the controls. Based upon the results of this study, afoxolaner/milbemycin oxime soft chewables were shown to be safe when administered repeatedly at up to 5× the maximum exposure dose in dogs as young as 8 weeks of age.