Pharmacokinetic and pharmacodynamic evaluations of a 10 mg/kg enrofloxacin intramuscular administration in bearded dragons (Pogona vitticeps): a preliminary assessment

Enrofloxacin (E) is commonly used in veterinary medicine. It is necessary to perform pharmacokinetic/dynamic studies to minimize the selection of resistant mutants of bacteria and extend the efficacy of antimicrobial agents. Eight healthy adult Pogona vitticeps were assigned into two groups of equal size and treated with a single intramuscular injection of E at 10 mg/kg. Blood samples were withdrawn at different scheduled times for each group, and rectal swabs were collected. E and ciprofloxacin (active metabolite) blood concentrations were quantified by an HPLC validated method, while the in vitro antimicrobial susceptibility was evaluated by the Kirby-Bauer disc diffusion susceptibility test. The pharmacokinetic profiles of E gave similar pharmacokinetic parameters irrespective of the collection time schedule. Bacteria isolation showed the presence of both E. coli, Salmonella enterica subspecies enterica and subspecies 3a, Proteus spp., and Pseudomonas spp. The majority of isolated colonies were sensitive to E, but the treatment did not reduce the number of bacteria in faeces. Results suggest that E is able to reach blood concentrations high enough to kill susceptible bacteria (MIC < 0.9 μg/mL), but at the same time does not significantly affect intestinal bacteria.

Pharmacokinetics and disposition of flupirtine in the horse

Flupirtine (FLU) is a non-opioid analgesic drug, with no antipyretic or anti-inflammatory effects, used in the treatment of a wide range of pain states in human beings. It does not induce the side effects associated with the classical drugs used as pain relievers. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy horses. Six mixed breed adult mares were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n = 3) received a single dose of 1 mg/kg of FLU injected IV into the jugular vein. Group 2 (n = 3) received FLU (5 mg/kg) via nasogastric tube. The animals then swapped groups after a 1-week wash-out period and the doses were repeated. Blood samples (5 mL) were collected at 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 10, 24, 36 and 48 h and plasma was then analysed by a validated HPLC method. Some mild and transient adverse effects (that spontaneously resolved within 5 min) were observed in 2/6 animals after IV administration. No adverse effects were noticed in the PO administration group. After IV and PO administrations, FLU was detectable in plasma for up to 36 h. The mean elimination half-life was longer after PO (10.27 h) than after IV (3.02 h) administration. The oral bioavailability was 71.4 ± 33.1%. After compartmental simulation/modelling, an oral dose of 2.6 mg/kg was calculated to give Cmax and AUC values in horses similar to those reported in humans after a clinical dose administration with a theoretical FLU effective plasma concentration of 187 ng/mL. These findings may form the basis for further studies concerning this active ingredient in equine medicine.

The pharmacokinetics and in vitro/ex vivo cyclooxygenase selectivity of parecoxib and its active metabolite valdecoxib in cats

Parecoxib (PX) is an injectable prodrug of valdecoxib (VX, which is a selective cyclo-oxyganase-2 (COX-2)) inhibitor licensed for humans. The aim of the present study was to evaluate pharmacokinetics and in vitro/ex vivo cyclooxygenase selectivity of PX and VX in cats. In a whole blood in vitro study, PX did not affect either COX enzymes whereas VX revealed a COX-2 selective inhibitory effect in feline whole blood. The IC50 values of VX for COX-2 and COX-1 were 0.45 and 38.6 µM, respectively. Six male cats were treated with 2.5 mg/kg of PX by intramuscular injection. PX was rapidly converted to VX with a relatively short half-life of 0.4 h. VX achieved peak plasma concentration (2.79 ± 1.59 µg/mL) at 7 h following PX injection. The mean residence times for PX and VX were 0.43 ± 0.15 and 5.94 ± 0.88 h, respectively. In the ex vivo study, PX showed a COX-2 inhibition rate of about 70% in samples taken at 1, 2, 4 and 10 h after injection, with a significant difference compared to the control. In contrast, COX-1 was slightly inhibited, ranging from 0.7% to 9.7% of the control inhibition rate without any significant difference for 24 h after PX administration. The preliminary findings of the present research appear promising and encourage further studies to investigate whether PX can be successfully used in feline medicine.

Pharmacokinetic profiles of the analgesic drug flupirtine in cats

Flupirtine (FLU) is a non-opioid analgesic drug with no antipyretic or antiphlogistic effects, used in the treatment of a wide range of pain states in human beings. There is a substantial body of evidence on the efficacy of FLU in humans but this is inadequate to recommend its off-label use in veterinary clinical practice. The aim of this study was to evaluate the pharmacokinetic profiles of FLU after IV and PO administration in healthy cats. Six mixed breed adult cats were randomly assigned to two treatment groups using an open, single-dose, two-treatment, two-phase, paired, cross-over design (2 × 2 Latin-square). Group 1 (n  =  3) received a single dose of 5 mg/kg of FLU injected IV into the jugular vein. Group 2 (n  =  3) received the same dose via PO route. The wash out period was 1 week. Blood samples (1 mL) were collected at assigned times and plasma was then analysed by a validated HPLC method. No adverse effects at the point of injection and no behavioural changes or alterations in health parameters were observed in the animals during or after the study (up to 7 days after the full study). After IV administration, FLU was detectable in plasma up to 36 h. After PO administration, FLU plasma concentrations were lower than those following IV administration, but they were detectable over the same time range. The terminal part of both mean pharmacokinetic curves showed a similar trend of elimination. The oral bioavailability was approximately 40%. This is the first study of FLU in an animal species of veterinary interest and it could pave the way for the use of this active ingredient in the veterinary field.

[Occupational diseases caused by artificial optical radiation (AOR)]

BACKGROUND

Italian national legislation guarantees safety and health for workers exposed to artificial optical radiations (AOR) by Legislative Decree 81/2008.

OBJECTIVES AND METHODS

Effects and damages to health resulting from AOR exposure were analyzed from literature data.

RESULTS

Ultraviolet radiations (UV), particularly those in the wavelength range between 220 and 310 nm, causes chronic conjunctivitis and kerato-conjunctivitis. Skin cancer caused by UV exposure included basal cell carcinoma, squamous cell carcinoma and melanoma. As regards Infrared Radiations (portion of the spectrum between 780 nm and 1 mm), the biological effect is essentially of thermal nature. Exposure to blue light (portion ofthe spectrum of visible light radiation in a wavelength range between 380 and 550 nm) causes exclusively retinal damage and is considered to be responsible for the development of situations of age-related macular degeneration (AMD). Even if experimental data are available, at the present time there is still no epidemiological evidence of retinal damage caused by blue light.

CONCLUSIONS

The forensic criteria for investigating the causality link between occupational exposure to AOR and damage, and the methodology necessary for the assessment process, are reported. Two lists of occupational diseases which were included in the Italian Ministerial Decrees, issued respectively on April 2008 and 11 December 2009, are also considered. Lastly, on the basis of the current existing guidelines and scientific evidence, the authors propose occupational health surveillance protocols for workers exposed to AOR risk.

[Work at high altitudes: risk factors and health surveillance]

Work at high altitude (elevation equal to or greater than 3000 m above sea level) results in a physiological adaptation of the human organism to changing environmental conditions. The main problem related to the altitude is represented by the reduction of partial pressure of oxygen (hypoxia). Our study takes into consideration occupational risk factors: those related to physical environment of high altitude; those related to the worker; those related to the characteristics of the job. It is finally addressed the decision making process related to the formulation of the judgment of suitability for performance of work activities at high altitude. The health protocol proposed requires an accurate anamnestic investigation aimed at gathering information on pre-existing pathophysiological conditions that need, once identified, clinical and instrumental tests specific and targeted. These clinical protocols are analyzed and proposed for the main pathophysiologic conditions that pose a risk to health at high altitude.

First measurement of chiral dynamics in π- γ → π- π- π+

The COMPASS Collaboration at CERN has investigated the π- γ → π- π- π+ reaction at center-of-momentum energy below five pion masses, sqrt[s]<5m(π), embedded in the Primakoff reaction of 190 GeV pions impinging on a lead target. Exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, t'<0.001  GeV2/c2. Using partial-wave analysis techniques, the scattering intensity of Coulomb production described in terms of chiral dynamics and its dependence on the 3π-invariant mass m(3π)=sqrt[s] were extracted. The absolute cross section was determined in seven bins of sqrt[s] with an overall precision of 20%. At leading order, the result is found to be in good agreement with the prediction of chiral perturbation theory over the whole energy range investigated.

PDE10A and PDE10A-dependent cAMP catabolism are dysregulated oppositely in striatum and nucleus accumbens after lesion of midbrain dopamine neurons in rat: a key step in parkinsonism physiopathology

Loss of dopamine neurons in experimental parkinsonism results in altered cyclic nucleotide cAMP and cGMP levels throughout the basal ganglia. Our objective was to examine whether expression of phosphodiesterase 10A (PDE10A), an isozyme presenting a unique distribution in basal ganglia, is altered after unilateral injection of 6-hydroxydopamine in the medial forebrain bundle, eliminating all midbrain dopaminergic neurons, such that cyclic nucleotide catabolism and steady state could be affected. Our study demonstrates that PDE10A mRNA levels were decreased in striatal neurons 10 weeks after 6-hydroxydopamine midbrain lesion. Such changes occurred in the striatum ipsilateral to lesion and were paralleled by decreased PDE10A protein levels and activity in striatal neurons and in striato-pallidal and striato-nigral projections. However, PDE10A protein and activity were increased while PDE10A mRNA was unchanged in the nucleus accumbens ipsilateral to the 6-hydroxydopamine midbrain lesion. Accordingly, cAMP levels were down-regulated in the nucleus accumbens, and up-regulated in the striatum ipsilateral to the lesion, but they were not significantly changed in substantia nigra and globus pallidus. Unlike cAMP, cGMP levels were decreased in all dopamine-deafferented regions. The opposite variations of cAMP steady state in striatum and nucleus accumbens are concordant and likely dependent, at least in part, on the down-regulation of PDE10A expression and activity in the former and its up-regulation in the latter. On the other hand, the down-regulation of cGMP steady state in the striato-nigral and striato-pallidal complex is not consistent with and is likely independent from the concomitant down-regulation of PDE10A. Therefore, dopamine loss inversely regulates PDE10A gene expression in the striatum and PDE10A post-transcription in the nucleus accumbens, therein differentially modulating PDE10A-dependent cAMP catabolism.