Replicate effects and test–retest reliability of quantitative sensory threshold testing in dogs with and without chronic pain

Objective

To evaluate replicate effects and test–retest reliability of mechanical and thermal quantitative sensory testing (QST) in normal dogs and dogs with osteoarthritis (OA)-associated pain.

Feasibility and repeatability of thermal quantitative sensory testing in normal dogs and dogs with hind limb osteoarthritis-associated pain

The objectives of this study were to determine whether thermal quantitative sensory testing (QST) can be performed in client-owned dogs, is repeatable and whether QST differs between normal dogs and dogs with hind limb osteoarthritis (OA). This clinical, prospective, observational study used clinically normal dogs (n = 23) and dogs with OA-associated hind limb pain (n = 9). Thermal QST was performed in standing dogs using a high-powered light source delivered by a previously validated system. Dogs were tested on two occasions, 2 weeks apart. Five tests were performed on each hind limb at each time point. Repeated measures analysis of variance was used to evaluate the effects of leg, time point and OA/normal status on thermal threshold latencies (TTL). Additionally, paired t tests were used to compare the TTL of left and right limbs within groups and between time points.Thermal thresholds were successfully measured in 32 client-owned dogs without prior training. TTL were significantly different between normal and OA dogs (P = 0.012). There was no difference between limbs (P = 0.744) or time periods (P = 0.572), when analyzed by repeated measures analysis of variance, and no interactions between group and limb, visit and limb, or visit and group. In conclusion, thermal thresholds can be measured in client owned dogs with no prior training and are repeatable from week to week. Further data are required to determine if OA results in thermal hypoalgesia as measured at the distal hind limb and whether this is an indication of central sensitization.     

Antinociceptive efficacy and plasma concentrations of transdermal buprenorphine in dogs

To assess the antinociceptive efficacy of transdermal (TD) buprenorphine (B) in dogs, a prospective, positive-controlled experimental study was performed in 10 healthy Beagles. In an open label crossover design, the dogs initially received intravenous B (IVB, 0.02 mg kg^?1) as a positive control, followed by TDB (52.5 μg h^?1) 4 months later. Blood was collected at regular intervals for determination of the plasma concentrations of B ([B]) and its metabolite norbuprenorphine. The antinociceptive efficacy was assessed using thermal and mechanical models of nociception. The peak concentration [B] was 1.54 ng mL^?1 (±1.98) 60 h after TDB application, although three dogs had no measurable [B] after TDB. Maximum thermal threshold (TT) was 52.6 °C (±0.48) at 1 h after IVB administration and 51.63 °C (±1.01) 72 h after TDB application. The significant increase in TT indicated that effective antinociception was achieved beyond 36 h after the application of TDB, lasting until patch removal. There was hysteresis between [B] and the antinociceptive effect.     

Increased chymase-like activity in a dog with congenital pulmonic stenosis

ObjectivesThis study was intended to compare the tissue chymase-like activity and angiotensin converting enzyme (ACE) activity in the right and left ventricles of a dog with congenital pulmonic stenosis (PS), with normal dogs, and to discuss the potential clinical implications of these findings.Animals, materials and methodsStudy subjects included a one-year-old Beagle dog with spontaneous PS and six clinically normal Beagles. Chymase-like and ACE activities were determined in all hearts by high pressure liquid chromatography.ResultsIn the PS dog right ventricular (RV) chymase-like activity (49.79 nmol/min/g tissue) and left ventricular (LV) chymase-like activity (36.85 nmol/min/g tissue) were elevated vs normal Beagle dogs (mean ± standard deviation, RV: 20.17 ± 5.24 nmol/min/g, LV: 19.03 ± 3.27 nmol/min/g).ConclusionsActivation of the tissue RAA system was detected in a dog with congenital PS. This interesting finding should be pursued with further studies to validate this result, and to explore whether pharmacological blockade of chymase, or the angiotensin II receptor, represents a useful strategy to prevent myocardial remodeling in this condition.     

Entamoeba infections in different populations of dogs in an endemic area of Lahore,Pakistan

Entamoeba histolytica, a protozoan parasite that affects humans and other primates all over the world. It is a common waterborne pathogen in endemic areas that have fecal oral transmission cycle. The aim of the present study was to examine the prevalence of E. histolytica and other Entamoeba species cysts in three different dog populations. Fecal samples from 600 dogs were collected and processed to detect Entamoeba cysts using the triple fecal test (light microscopy) and fecal antigens of E. histolytica were detected using a fecal antigen ELISA (TechLab E. histolytica II). Because it is impossible to differentiate E. histolytica from Entamoeba dispar and E. moshkovskii, using light microscopy we referred to all cysts morphologically consistent with E. histolytica as E. histolytica/dispar/moskovskii to reflect this uncertainty. Samples from 197 household dogs without clinical signs, 122 samples from household dogs exhibiting clinical signs of diarrhea, dysentery and vomiting and 281 stray dogs with no specific clinical signs were examined. Entamoeba histolytica-like cysts were observed in 94 (15.6%, 95% CI = ±3.88) by triple fecal test microscopy and E. histolytica antigens were demonstrated in 66 (11%, 95% CI = ±4.41) by fecal antigen ELISA in 600 fecal samples. Significant differences (P ≤ 0.05) in prevalence were found between the three populations. Twenty (10.1%, 95% CI = ±7.86) and 11 (5.6%, 95% CI = ±7.70) of 197 fecal samples from household dogs without clinical signs were positive by microscopy and by antigen ELISA, respectively. Twenty-nine (23.8%, 95% CI = ±6.58) and 23 (18.8%, 95% CI = ±7.81) of 122 the fecal samples from household dogs with clinical signs were positive by microscopy and by antigen ELISA, respectively. Forty-five (16.01%, 95% CI = ±5.62) and 32 (11.3%, 95% CI = ±6.38) of 281 fecal samples from stray dogs were positive by microscopy and by fecal antigen ELISA, respectively. Dogs from the youngest age group (6 months to 1 year) were more likely to be E. histolytica antigen positive than were dogs from the other two older age groups, with a significant difference (P ≤ 0.05) between all age groups. Statistically, no significant (P ≥ 0.05) difference of prevalence was seen in male and female dogs. The local dogs had the highest prevalence rate of E. histolytica antigens (36 of 246, 14.2%, 95% CI = ±6.32) followed by imported breeds (11 of 115, 9.5%, 95% CI = ±10.4) and crossbred (19 of 239, 8.3%, 95% CI = ±7.47), indicating a significant (P ≤ 0.05) trend of positivity between various breeds of dogs. These findings suggest that dogs may play an important role in the epidemiology of this pathogen.     

Effect of dexmedetomidine vs. acepromazine–methadone premedication on limb to lung circulation time in dogs

The study compared limb-to-lung circulation times (CT) in dogs under general anaesthesia after premedication with dexmedetomidine (DEX) or acepromazine–methadone (ACE–M). Healthy male and female dogs (n = 20) were randomly assigned to receive acepromazine 0.04 mg/kg and methadone 0.2 mg/kg intramuscularly (IM), or DEX 0.01 mg/kg IM. Anesthesia was induced with propofol and maintained with isoflurane at similar concentration in both groups. Mechanical ventilation was started immediately (20 breaths/min; inspiratory to expiratory ratio 1:2) and tidal volume was adjusted to achieve an end-tidal CO₂ concentration (PE’CO₂) of between 3.9 and 5.3 kPa. Ten minutes later arterial blood gas was analyzed and baseline data recorded for 3 minutes. A single dose of sodium bicarbonate 0,5 mEq/kg was administered intravenously over 10 s starting with inspiration. Limb-to-lung CT was defined as the time interval between the start of bicarbonate injection and the recording of the highest PE’CO₂.Following bicarbonate administration, PE’CO2 increased, and then rapidly decreased to baseline in both groups. CT was shorter in the ACE–M group (20 ± 2.3 vs. 27 ± 5.1 s). Bodyweight was higher in the ACE–M group (30.6 ± 3.9 vs. 23.3 ± 6.8 kg). Mean arterial blood pressure was higher in the DEX group (92 ± 9 vs. 73 ± 7 mm Hg) but premedication with DEX significantly prolonged CT compared to premedication with ACE–M.     

Age and Body Condition of Goats Influence Consumption of Juniper and Monoterpene-Treated Feed

Redberry juniper (Juniperus pinchotii Sudworth) is an invasive, evergreen tree that is rapidly expanding throughout western and central Texas. Goats will consume some juniper on rangelands; however, intake is limited. The objective of our research was to determine how the age and body condition of goats influence their consumption of juniper and an artificial feed containing 4 monoterpenes. Two separate experiments were conducted. Experiment 1 examined the intake of redberry juniper foliage and used 39 goats either young (2 yr) or mature (> 6 yr). One-half of each age group was fed appropriate basal rations to reach either a high (HBC) or low body condition (LBC). Goats in LBC ate more (P < 0.01, 8.6 g · kg⁻¹ body weight [BW] ± 0.7 SE) juniper than those in HBC (2.3 g · kg⁻¹ BW ± 0.3 SE), and young animals consumed more (P < 0.05, 7.2 g · kg⁻¹ BW ± 0.7 SE) juniper than mature goats (3.9 g · kg⁻¹ BW ± 0.5 SE) across body condition treatments. In experiment 2, 36 goats, either young (2 yr) or mature (> 6 yr) and in either HBC or LBC, were offered a synthetic ration treated with 20.8 g · kg⁻¹ of 4 monoterpenes found in redberry juniper. Goats in LBC ate more (P < 0.01, 25.3 g · kg⁻¹ BW ± 1.0 SE) of the terpene-treated feed than those in HBC (17.5 g · kg⁻¹ BW ± 0.7 SE), and young animals ate more (P < 0.05, 22.5 g · kg⁻¹ BW ± 0.8 SE) than mature goats (20.3 g · kg⁻¹ BW ± 0.8 SE) across body condition treatments. Total intake as a proportion of body weight was also affected by body condition. Age and body condition are important factors that influence intake of chemically defended plants. A better understanding of how these attributes affect diet selection will aid livestock producers in improving grazing management.     

Pharmacokinetics of mequindox and its metabolites in rats after intravenous and oral administration

Pharmacokinetics of mequindox (MEQ) and its metabolites were determined in rats after intravenous (i.v.) and oral (p.o.) administration of MEQ at a single dose of 10 mg kg⁻¹ bodyweight. After both administrations, MEQ and five of its metabolites were quantified, except M4, whereas M1 and M2 were the predominant ones. The areas under the concentration–time curves (h ng mL⁻¹) of MEQ, M1, M2, M3, M5 and M10 after i.v. administration were 7559 ± 495, 6354 ± 2761, 5586 ± 2337, 1034 ± 160, 2370 ± 791 and 1813 ± 622, respectively, whereas after p.o. administration, remained as 2809 ± 40, 4361 ± 3544, 4351 ± 1046, 1444 ± 814, 3864 ± 305 and 1213 ± 569, respectively. The elimination half-lives (h) of these compounds after i.v. administration were 3.48 ± 0.80, 4.20 ± 0.76, 6.25 ± 2.41, 4.77 ± 1.54, 4.69 ± 1.62 and 16.89 ± 5.15, respectively, and were 3.21 ± 0.40, 3.66 ± 1.06, 4.20 ± 1.03, 8.91 ± 5.99, 4.20 ± 2.02 and 20.84 ± 10.85 after p.o. administration, respectively. After p.o. administration, the bioavailability of MEQ was 37.16%. The results showed that MEQ was extensively metabolized in rats and rapidly absorbed after p.o. administration.     

Contrast echocardiography in Boxer dogs with and without aortic stenosis

ObjectivesThe aim of this study was to investigate whether contrast echocardiography could enhance the subcostal Doppler signal for aortic flow measurements and achieve myocardial opacification, in Boxer dogs with and without AS.BackgroundIn evaluating dogs for aortic stenosis (AS) subcostal Doppler echocardiography was used for measurement of the aortic flow velocity, a measurement that can sometimes be difficult to perform in Boxer dogs.Animals, materials, and methodsCardiac auscultation, phonocardiographic and echocardiographic examinations, including a contrast study with Optison, were performed on 29 Boxer dogs selected based on previous examinations.ResultsThe initial subcostal Doppler signal was weak in 66% of the dogs and a marked improvement was seen in all dogs after contrast injection. The peak aortic flow velocity increased 5% from 2.58 ± 1.42 m/s before contrast to 2.71 ± 1.54 m/s after contrast (p = 0.003). This corresponds to a 2.8 mmHg increase in the pressure gradient from 26.6 mmHg before to 29.4 mmHg after contrast. A dose of 0.05–0.1 mL of Optison administered intravenously resulted in approximately 4 min of Doppler signal enhancement. With the present technique contrast echocardiography did not achieve myocardial opacification.ConclusionsSingle use of the contrast agent Optison can be recommended for enhancement of the subcostal Doppler signal in dogs, in which plain Doppler signals are difficult to obtain. Albeit statistically significant, the mild increase in peak aortic flow velocity after contrast was not considered biologically or clinically significant.     

Comparative pharmacokinetics of an injectable cephalexin suspension in beef cattle

This study describes and compares the pharmacokinetics of a single 7.5 mg/kg dose of cephalexin monohydrate oil-based 20% suspension after its administrations to six cows by the intramuscular (i.m.) and subcutaneous (s.c.) routes, and to five calves by the i.m. route. Significantly (P < 0.05) higher peak plasma concentrations (5.6 ± 0.79 μg/ml versus 3.93 ± 1.24 μg/ml) and lower half-life (1.81 ± 0.56 h versus 4.21 ± 0.82 h) and mean residence time (4.12 ± 1.07 h versus 6.63 ± 0.85 h) were obtained after i.m. administration when compared to the s.c. administration to cows. No differences were found between pharmacokinetic parameters calculated for cows and calves. Cephalexin plasma concentrations remained above 0.5–0.75 μg/ml for 11–14 h and 8–9 h after the s.c. and i.m. administrations, respectively. Thus, route of administration may be an important issue to be considered when calculating dosage schedules for successful treatments and safe withdrawal times for veterinary medicines.     

The effect of maropitant on intraoperative isoflurane requirements and postoperative nausea and vomiting in dogs: a randomized clinical trial

ObjectiveTo establish if preoperative maropitant significantly reduced intraoperative isoflurane requirements and reduced clinical signs associated with postoperative nausea and vomiting (PONV) in dogs.Study designRandomized clinical trial.AnimalsTwenty-four healthy, client-owned dogs undergoing routine ovariohysterectomy.MethodsPremedication involved acepromazine (0.03 mg kg⁻¹) combined with methadone (0.3 mg kg⁻¹) intramuscularly 45 minutes before anaesthetic induction with intravenous (IV) propofol, dosed to effect. Meloxicam (0.2 mg kg⁻¹) was administered intravenously. Dogs were randomly assigned to administration of saline (group S; 0.1 mL kg⁻¹, n = 12) or maropitant (group M; 1 mg kg⁻¹, n = 12) subcutaneously at time of premedication. Methadone (0.1 mg kg⁻¹ IV) was repeated 4 hours later. Anaesthesia was maintained with isoflurane in oxygen, dosed to effect by an observer unaware of group allocation. The dogs were assessed hourly, starting 1 hour postoperatively, using the short form of the Glasgow Composite Pain Score (GCPS), and for ptyalism and signs attributable to PONV [score from 0 (none) to 3 (severe)] by blinded observers. Owners completed a questionnaire at the postoperative recheck.ResultsOverall mean ± standard deviation end-tidal isoflurane percentage was lower in group M (1.19 ± 0.26%) than group S (1.44 ± 0.23%) (p = 0.022), but was not significantly different between groups at specific noxious events (skin incision, ovarian pedicle clamp application, cervical clamp application, wound closure). Cardiorespiratory variables and postoperative GCPS were not significantly different between groups. Overall, 50% of dogs displayed signs attributable to PONV, with no difference in PONV scores between groups (p = 0.198). No difference in anaesthetic recovery was noted by owners between groups.ConclusionsMaropitant reduced overall intraoperative isoflurane requirements but did not affect the incidence of PONV.Clinical relevanceMaropitant provided no significant benefits to dogs undergoing ovariohysterectomy with this anaesthetic and analgesic protocol, although clinically significant reductions in isoflurane requirements were noted.     

Pharmacokinetics of erythromycin after intravenous,intramuscular and oral administration to cats

The aim of this study was to characterise the pharmacokinetic properties of different formulations of erythromycin in cats. Erythromycin was administered as lactobionate (4 mg/kg intravenously (IV)), base (10 mg/kg, intramuscularly (IM)) and ethylsuccinate tablets or suspension (15 mg/kg orally (PO)). After IV administration, the major pharmacokinetic parameters were (mean ± SD): area under the curve (AUC)_(0–∞) 2.61 ± 1.52 μg h/mL; volume of distribution (V_z) 2.34 ± 1.76 L/kg; total body clearance (Cl_t) 2.10 ± 1.37 L/h kg; elimination half-life (t_½λ) 0.75 ± 0.09 h and mean residence time (MRT) 0.88 ± 0.13 h. After IM administration, the principal pharmacokinetic parameters were (mean ± DS): peak concentration (C_max), 3.54 ± 2.16 μg/mL; time of peak (T_max), 1.22 ± 0.67 h; t_½λ, 1.94 ± 0.21 h and MRT, 3.50 ± 0.82 h. The administration of erythromycin ethylsuccinate (tablets and suspension) did not result in measurable serum concentrations. After IM and IV administrations, erythromycin serum concentrations were above minimum inhibitory concentration (MIC)₉₀ = 0.5 μg/mL for 7 and 1.5 h, respectively. However, these results should be interpreted cautiously since tissue erythromycin concentrations have not been measured and can reach much higher concentrations than in blood, which may be associated with enhanced clinical efficacy.     

In vivo efficacy of tamarind (Tamarindus indica) fruit extract on experimental fluoride exposure in rats

The study was undertaken to determine the efficacy of hydro-methanolic (1:1) extract of tamarind (Tamarindus indica L.) fruit pulp in removing body fluoride burden. Thirty rats were divided into five groups. Keeping no fluoride group as the control, rats of no treatment, low dose, middle dose and high dose groups received sodium fluoride orally at the rate of 200 mg per kg body weight daily for 14 weeks. Rats of low dose, middle dose and high dose group simultaneously received tamarind fruit pulp extract at three doses, viz. 25 (low), 50 (medium) and 100 mg (high) per kg body weight orally, respectively. Fluoride concentration in blood, urine and long bone of experimental rats was monitored to assess the efficacy of the extract. Mean serum fluoride concentration in fluoride exposed rats was 0.145 ± 0.009 and 0.783 ± 0.042 μg/ml on days 0 and 98. In comparison, fluoride concentrations in tamarind treated rats were 0.179 ± 0.021 and 0.633 ± 0.015; 0.179 ± 0.021 and 0.502 ± 0.025 and 0.176 ± 0.021 and 0.498 ± 0.030 μg/ml in low, medium and high dose groups, respectively on day 0 and day 98 of the experiment. There was a significant (p ⩽ 0.01) increase in urinary fluoride excretion from day 28 onwards. The mean fluoride concentration in long bones of treated rats was significantly lower than the values recorded in fluoride exposed rats. These findings suggest that concomitant use of tamarind fruit pulp extract can reduce fluoride concentration in blood and bone and enhanced urinary excretion, indicating the ameliorative potential of fruits of tamarind in fluoride toxicity.     

Arrhythmogenic right ventricular cardiomyopathy in Boxer dogs is associated with calstabin2 deficiency

ObjectiveTo examine the presence and effect of calstabin2-deficiency in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy (ARVC).AnimalsThirteen Boxer dogs with ARVC.Materials and methodsTissue samples were collected for histopathology, oligonucleotide microarray, PCR, immunoelectrophoresis, ryanodine channel immunoprecipitation and single-channel recordings, and calstabin2 DNA sequencing.ResultsIn cardiomyopathic Boxer dogs, myocardial calstabin2 mRNA and protein were significantly decreased as compared to healthy control dogs (calstabin2 protein normalized to tetrameric cardiac ryanodine receptor (RyR2) complex: affected, 0.51 ± 0.04; control, 3.81 ± 0.22; P < 0.0001). Calstabin2 deficiency in diseased dog hearts was associated with a significantly increased open probability of single RyR2 channels indicating intracellular Ca²⁺ leak. PCR-based sequencing of the promoter, exonic and splice site regions of the canine calstabin2 gene did not identify any causative mutations.ConclusionsCalstabin2 deficiency is a potential mechanism of Ca²⁺ leak-induced ventricular arrhythmias and heart disease in Boxer dogs with ARVC.     

Characterization of oral double balloon endoscopy in the dog

Exploration of the canine small intestine using conventional endoscopy is restricted to the duodenum and/or the ileum. Double balloon endoscopy (DBE) is a ‘push and pull’ technique that has been described in humans and permits a complete exploration of the small intestine. In this study, oral DBE was performed on 12 healthy dogs (10–34 kg) to characterize for the first time the efficiency, exploration dynamics and safety of the technique.DBE was successful in 83% of dogs; the average estimated insertion depth of the endoscope was 287 ± 36 cm, and the average duration of the exploration was 84 ± 8 min. No complications or relevant adverse clinical effects were observed, and there was no indication of post-procedure pancreatitis based on serology of two specific markers of pancreatitis (amylase and lipase) and the immediate nonspecific inflammatory mediator C-reactive protein. The study showed that oral DBE is viable and safe in the dog, allowing for the diagnosis and treatment of gastrointestinal diseases deep in the small intestine to an extent that has not previously been possible using conventional endoscopy.     

Nutritional management of inherited copper-associated hepatitis in the Labrador retriever

Canine hereditary copper-associated hepatitis is characterized by gradual hepatic copper accumulation eventually leading to liver cirrhosis. Therapy is aimed at creating a negative copper balance with metal chelators, of which d-penicillamine is the most commonly used. d-penicillamine often causes gastro-intestinal side effects and life-long continuous therapy may lead to a deficiency of copper and zinc. The aim of the current study was to investigate the effect of a low-copper, high-zinc diet as an alternative to continuous d-penicillamine treatment for the long-term management of canine copper-associated hepatitis.Sixteen affected Labrador retrievers were followed for a median time period of 19.1 months (range, 5.9–39 months) after being effectively treated with d-penicillamine. The dogs were maintained on a diet containing 1.3 ± 0.3 mg copper/1000 kcal and 64.3 ± 5.9 mg zinc/1000 kcal. Liver biopsies were taken every 6 months for histological evaluation and copper determination. Plasma alanine aminotransferase (ALT) and alkaline phosphatase, as well as serum albumin were determined.Dietary treatment alone was sufficient to maintain hepatic copper concentration below 800 mg/kg dry weight liver in 12 dogs during the study period. Four dogs needed re-treatment with d-penicillamine. ALT activity and albumin concentration were not associated with hepatic copper concentration, but showed a significant association with the stage and grade of hepatitis respectively. In conclusion, a low-copper, high-zinc diet can be a valuable alternative to continuous d-penicillamine administration for long-term management of dogs with copper-associated hepatitis. The copper re-accumulation rate of an individual dog should be considered in the design of a long-term management protocol and in determining re-biopsy intervals.     

Estimation of direct and maternal (co)variance components for pre-weaning growth traits in Muzaffarnagari sheep

Genetic parameters and (co)variance components were estimated for weight at birth and at 15, 30, 45, 60 and 75 days of age for a flock of Muzaffarnagari sheep maintained at the Central Institute for Research on Goats, Makhdoom, Mathura over a period of 27 years (1976–2002). Records on 5201 lambs descended from 1568 ewes and 170 rams were included in the analysis. Analyses were carried out by REML fitting an animal model and ignoring or including maternal genetic or permanent environmental effects. Six different animal models were fitted for all traits, and the best model was chosen after testing improvements in log-likelihood values. Direct heritability estimates were inflated substantially for all traits when maternal effects were ignored. Direct heritability estimates were 0.08 ± 0.02 for birth weight and 0.02 ± 0.02, 0.02 ± 0.02, 0.27 ± 0.08, 0.09 ± 0.04, and 0.29 ± 0.08 for weights at 15, 30, 45, 60, and 75 days, respectively. Maternal genetic effects contributed only 4 to 8% of the total phenotypic variance from birth to 30 days of age, and this effect diminished further with increasing age. Maternal heritability was low for pre-weaning growth traits and should have only a small effect on selection response. Estimates of the fraction of variance due to maternal permanent environmental effects were 0.09 ± 0.02, 0.15 ± 0.04, 0.12 ± 0.03, 0.11 ± 0.04, 0.14 ± 0.02, and 0.08 ± 0.04 for body weights at birth and at 15, 30, 45, 60, and 75 days, respectively. These results indicate that selecting for improved maternal and/or direct effects in Muzaffarnagari sheep would generate only slow genetic progress in early growth traits.     

Pharmacokinetics,plasma protein binding and bioavailability of moxifloxacin in Muscovy ducks after different routes of administration

In this study the disposition kinetics and plasma availability of moxifloxacin in Muscovy ducks after single intravenous (i.v.), intramuscular (i.m.) and oral (p.o.) administrations of 5 mg kg^?1 b.wt. were investigated. The concentrations of moxifloxacin in the plasma were measured using high-performance liquid chromatography (HPLC) with fluorescence detection on samples collected at frequent intervals after drug administration. Following intravenous injection, the decline in plasma drug concentration was bi-exponential with half-lives of (t_1/2α) 0.22 ± 0.10 h and (t_1/2β) 2.49 ± 0.26 h for distribution and elimination phases, respectively. The volume of distribution at steady-state (V_dss) was 1.02 ± 0.14 l kg^?1 and the total body clearance (Cl_tot) was 0.32 ± 0.11 l kg^?1 h^?1, respectively. After intramuscular and oral administration of moxifloxacin at the same dose the peak plasma concentrations (C_max) were 2.38 ± 0.43 and 2.11 ± 0.36 μg ml^?1 and were obtained at 1.47 ± 0.26 and 1.83 ± 0.16 h (T_max), respectively, the elimination half-lives (T_1/2el) were 3.14 ± 0.42 and 2.63 ± 0.44 h, respectively, and AUC_0–24 were 15.87 ± 2.35 and 14.52 ± 2.37 μg ml^?1 h^?1, respectively. The systemic bioavailabilities were 96.36 ± 11.54% and 86.79 ± 12.64%, respectively. In vitro plasma protein binding percent was 32%. We concluded that moxifloxacin might be clinically interesting alternative for the treatment of most sensitive bacterial infections in Muscovy ducks.     

Relationship between the melanocortin-1 receptor (MC1R) variant R306ter and physiological responses to mechanical or thermal stimuli in Labrador Retriever dogs

Objective

Variants in the MC1R gene have been associated with red hair color and sensitivity to pain in humans. The study objective was to determine if a relationship exists between MC1R genotype and physiological thermal or mechanical nociceptive thresholds in Labrador Retriever dogs.