Myocardial strain imaging: review of general principles, validation, and sources of discrepancies.

Myocardial tissue tracking imaging techniques have been developed for a more accurate evaluation of myocardial deformation (i.e. strain), with the potential to overcome the limitations of ejection fraction (EF) and to contribute, incremental to EF, to the diagnosis and prognosis in cardiac diseases. While most of the deformation imaging techniques are based on the similar principles of detecting and tracking specific patterns within an image, there are intra- and inter-imaging modality inconsistencies limiting the wide clinical applicability of strain. In this review, we aimed to describe the particularities of the echocardiographic and cardiac magnetic resonance deformation techniques, in order to understand the discrepancies in strain measurement, focusing on the potential sources of variation: related to the software used to analyse the data, to the different physics of image acquisition and the different principles of 2D vs. 3D approaches. As strain measurements are not interchangeable, it is highly desirable to work with validated strain assessment tools, in order to derive information from evidence-based data. There is, however, a lack of solid validation of the current tissue tracking techniques, as only a few of the commercial deformation imaging softwares have been properly investigated. We have, therefore, addressed in this review the neglected issue of suboptimal validation of tissue tracking techniques, in order to advocate for this matter.

The effect of commonly used anticoccidials and antibiotics in a subclinical necrotic enteritis model.

Necrotic enteritis poses an important health risk to broilers. The ionophore anticoccidials lasalocid, salinomycin, maduramicin, narasin and a combination of narasin and nicarbazin were tested in feed for their prophylactic effect on the incidence of necrotic enteritis in a subclinical experimental infection model that uses coccidia as a predisposing factor. In addition, drinking water medication with the antibiotics amoxicillin, tylosin and lincomycin was evaluated as curative treatment in the same experimental model. The minimal inhibitory concentrations (MICs) of all antibiotics and anticoccidials were determined in vitro against 51 Clostridium perfringens strains isolated from broilers. The strains examined appeared uniformly susceptible to lasalocid, maduramicin, narasin, salinomycin, amoxicillin and tylosin, whereas an extended frequency distribution range of MICs for lincomycin was seen, indicating acquired resistance in 36 isolates in the higher range of MICs. Nicarbazin did not inhibit the in vitro growth of the C. perfringens strains even at a concentration of 128 microg/ml. Supplementation of the diet from day 1 onwards with lasalocid, salinomycin, narasin or maduramicin led to a reduction in birds with necrotic enteritis lesions as compared with the non-medicated infected control group. A combination product of narasin and nicarbazin had no significant protective effect. Treatment with amoxicillin, lincomycin and tylosin completely stopped the development of necrotic lesions.

Screening of bovine coagulase-negative staphylococci from milk for superantigen-encoding genes.

A collection of 102 coagulase-negative staphylococci (CNS), isolated from cases of subclinical and clinical bovine mastitis and belonging to 10 different species, were screened by PCR for the presence of genes encoding enterotoxins and enterotoxin-like toxins (sea, seb, sec, sed, see, seg, seh, sei, sej, selk, sell, selm, seln, selo, selp, selq and selu), toxic shock syndrome toxin-1 (tst), and exfoliative toxins A and B (eta and etb). No toxin gene sequences were amplified from any of the isolates, indicating that superantigens encoded by genes detectable by the PCR tests used were not involved in the development of subclinical and clinical mastitis in cattle infected with the CNS isolates tested.

Pharmacokinetic-pharmacodynamic integration of orbifloxacin in rabbits after intravenous, subcutaneous and intramuscular administration.

The single-dose disposition kinetics of orbifloxacin were determined in clinically normal rabbits (n=6) after intravenous (i.v.), subcutaneous (s.c.) and intramuscular (i.m.) administration of 5 mg/kg bodyweight. Orbifloxacin concentrations were determined by high performance liquid chromatography with fluorescence detection. Minimal inhibitory concentrations (MICs) assay of orbifloxacin against 30 strains of Staphylococcus aureus from several European countries was performed in order to compute pharmacodynamic surrogate markers. The concentration-time data were analysed by compartmental and noncompartmental kinetic methods. Steady-state volume of distribution (V(ss)) and total body clearance (Cl) of orbifloxacin after i.v. administration were estimated to be 1.71+/-0.38 L/kg and 0.91+/-0.20 L/h x kg, respectively. Following s.c. and i.m. administration orbifloxacin achieved maximum plasma concentrations of 2.95+/-0.82 and 3.24+/-1.33 mg/L at 0.67+/-0.20 and 0.65+/-0.12 h, respectively. The absolute bio-availabilities after s.c. and i.m. routes were 110.67+/-11.02% and 109.87+/-8.36%, respectively. Orbifloxacin showed a favourable pharmacokinetic profile in rabbits. However, on account of the low AUC/MIC and C(max)/MIC indices obtained, its use by i.m. and s.c. routes against the S. aureus strains assayed in this study cannot be recommended given the risk of selection of resistant populations.

Disposition kinetics and pharmacokinetics--pharmacodynamic integration of difloxacin against Staphylococcus aureus isolates from rabbits.

The pharmacokinetics of difloxacin were studied following intravenous (IV), subcutaneous (SC) and oral administration of 5mg/kg to healthy white New Zealand rabbits (n = 6). Difloxacin concentrations were determined by HPLC assay with fluorescence detection. Minimal inhibitory concentrations (MICs) assay of difloxacin against different strains of S. aureus from different european countries was performed in order to compute the main pharmacodynamic surrogate markers. The plasma difloxacin clearance (Cl) for the IV route was (mean +/- SD) 0.41 +/- 0.05 L/h kg. The steady-state volume of distribution (V(ss)) was 1.95 +/- 0.17 L/kg. The terminal half-life [Formula: see text] was (mean+/-SD) 4.19+/-0.34 h, 7.53 +/- 1.32 h and 8.00 +/- 0.45 h after IV, IM and oral, respectively. From this data, it seems that a 5 mg/kg dose difloxacin would be effective by SC and oral routes in rabbits against bacterial isolates with MIC0.1 microg/mL.

Pharmacokinetic-pharmacodynamic integration of danofloxacin after intravenous, intramuscular and subcutaneous administration to rabbits.

The pharmacokinetics of danofloxacin was studied following intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) administration of 6 mg/kg to healthy rabbits. Danofloxacin concentration were determined by high-performance liquid chromatography assay with fluorescence detection. Minimal inhibitory concentrations (MICs) assay of danofloxacin against 30 strains of Staphylococcus aureus from several European countries was performed in order to compute pharmacodynamic surrogate markers. The danofloxacin plasma concentration versus time data after i.v. administration could best be described by a two-compartment open model. The disposition of i.m. and subcutaneously administered danofloxacin was best described by a one-compartment model. The terminal half-life for i.v., i.m. and s.c. routes was 4.88, 6.70 and 8.20 h, respectively. Clearance value after i.v. dosing was 0.76 L/kg.h. After i.m. administration, the absolute bioavailability was mean (+/-SD) 102.34 +/- 5.17% and the Cmax was 1.87 mg/L. After s.c. administration, the absolute bioavailability was mean (+/-SD) 96.44 +/- 5.95% and the Cmax was 1.79 mg/L. Danofloxacin shows a favourable pharmacokinetics profile in rabbits reflected by parameters such as a long half-life and a high bioavailability. However, in consideration of the low AUC/MIC indices obtained, its use by i.m. and s.c. route against the S. aureus strains assayed in this study cannot be recommended given the risk for selection of first mutant subpopulations.

International dissemination of a high virulence rabbit Staphylococcus aureus clone.

High virulence rabbit Staphylococcus aureus strains cause chronic and spreading problems of mastitis, pododermatitis and subcutaneous abscesses on rabbit flock level, whereas infections with low virulence strains are limited to individual rabbits. In the present report, 13 high virulence rabbit S. aureus strains, selected out of a large collection of strains isolated in five European countries between 1983 and 2004, were genotyped using pulsed-field gel electrophoresis, spa typing, multilocus sequence typing (MLST) and accessory gene regulator (agr) group typing. Two low virulence rabbit S. aureus strains were also included in the study. The results indicate the clonal origin of high virulence rabbit S. aureus strains present in Europe. Furthermore, the results of MLST and spa typing form a basis for international epidemiology of rabbit S. aureus strains, as these DNA sequence-based typing techniques can easily be used for intercentre comparisons.

Inclusion body disease in snakes: a review and description of three cases in boa constrictors in Belgium.

Inclusion body disease, a fatal disorder in Boidae, is reviewed, and three cases in boa constrictors, the first reported cases in Belgium, are described. The snakes showed nervous signs, and numerous eosinophilic intracytoplasmic inclusions, which are considered to be characteristic of the disease, were found in the liver and pancreas. The disease is suspected to be caused by a retrovirus, but transmission electron microscopic examinations of several tissues from one of the snakes did not reveal particles with a typical retroviral morphology.

Pharmacokinetic-pharmacodynamic integration of moxifloxacin in rabbits after intravenous, intramuscular and oral administration.

The pharmacokinetics of moxifloxacin was studied following intravenous (i.v.), intramuscular (i.m.) and oral dose of 5 mg/kg to healthy white New Zealand rabbits (n = 6). Moxifloxacin concentrations were determined by HPLC assay with fluorescence detection. The moxifloxacin plasma concentration vs. time data after i.v. administration could best be described by a two-compartment open model. The disposition of i.m. and orally administered moxifloxacin was best described by a one-compartment model. The plasma moxifloxacin clearance (Cl) for the i.v route was (mean +/- SD) 0.80 +/- 0.02 L/h.kg. The steady-state volume of distribution (Vss) was 1.95 +/- 0.18 L/kg. The terminal half-life (t(1/2lambdaz)) was (mean +/- SD) 1.84 +/- 0.12, 2.09 +/- 0.05 and 2.15 +/- 0.07 h after i.v., i.m. and oral, respectively. Minimal inhibitory concentration (MIC) assays of moxifloxacin against different strains of S. aureus were performed in order to compute pharmacodynamic surrogate markers. From these data, it is concluded that a 5 mg/kg dose moxifloxacin would be effective by i.m. and oral routes in rabbits against bacterial isolates with MIC < or = 0.06 microg/mL and possibly for MIC < or = 0.12 microg/mL, but in the latter case a higher dose would be required.