Plasma pharmacokinetics and synovial fluid concentrations after oral administration of single and multiple doses of celecoxib in greyhounds

OBJECTIVE: To determine the plasma pharmacokinetics and synovial fluid concentrations after oral administration of single and multiple doses of celecoxib in Greyhounds. ANIMALS: 7 adult Greyhounds. PROCEDURES: Dogs received celecoxib (median dose, 11.8 mg/kg [range, 11.5 to 13.6 mg/kg], PO, q 24 h) for 10 days. Blood samples were collected prior to administration of celecoxib and serially for 24 hours after the 1st and 10th doses were administered. A synovial joint catheter was placed into a stifle joint in each dog for collection of synovial fluid samples. Concentrations of celecoxib in plasma and synovial fluid were quantified by use of a validated liquid chromatography/mass spectrometry method. Identification of hydroxy- and carboxyl-celecoxib in plasma and synovial fluid was also performed. Pharmacokinetic parameters were determined by use of noncompartmental analysis. RESULTS: Administration of multiple doses of celecoxib resulted in a significant decrease (40%) in median area under the curve (AUC) values and a corresponding decrease in median maximum concentrations (Cmax; 2,620 to 2,032 ng/mL) between the 1st and 10th doses. Synovial fluid concentrations were less than the corresponding plasma concentrations at all times except 24 hours after administration of the 10th dose of celecoxib. CONCLUSIONS AND CLINICAL RELEVANCE: Celecoxib distributes into the synovial fluid of Greyhounds. Although the exact mechanism for the decreases in AUC and Cmax is not known, results suggested that the plasma pharmacokinetics of celecoxib are different after administration of multiple doses in Greyhounds. These findings warrant further investigation on the absorption, distribution, metabolism, and elimination of celecoxib in Greyhounds and other breeds of dogs.     

Changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and association with racing performance

OBJECTIVE: To evaluate changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and determine whether there was any relationship between cardiac dimensions and racing performance. DESIGN: Longitudinal observational study. ANIMALS: 103 horses. PROCEDURE: 2-dimensional and M-mode echocardiography was performed 4 times at 6-month intervals. RESULTS: Significant cardiac enlargement took place during the study period as indicated by increases in left ventricular internal diameter in diastole (LVIDd), estimated left ventricular muscle mass (LV mass), and mean wall thickness attributable to eccentric left ventricular hypertrophy. Estimated body weight was positively correlated with left ventricular size, and males had significantly larger LVIDd and LV mass than did females. Horses that were racing regularly had larger LVIDd and LV mass than did unraced horses. A significant relationship between left ventricular size and racing performance was observed. The relationship was strongest at the time of the fourth examination. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that age must be taken into account when interpreting results of echocardiography in young Standardbred racehorses because significant cardiac enlargement takes place with age and training. A larger heart was found in horses that were racing, and size of the heart was correlated with athletic performance of the horse.     

Prevalence of respiratory signs and identification of risk factors for respiratory morbidity in Swedish Yorkshire terriers

Yorkshire terriers may be prone to respiratory disease; however, limited epidemiological information is available. A cross-sectional study design was used to compare the prevalence of respiratory signs in Yorkshire terriers with the prevalence in a population of dogs in general and to identify risk factors for respiratory clinical signs within the Swedish population of Yorkshire terriers. Data on clinical signs and risk factors were obtained from a questionnaire. The prevalence of respiratory signs in general (RS) was significantly higher among Yorkshire terriers compared with control dogs (RS 56.3 per cent and 23.0 per cent), and likewise more frequent respiratory signs (FRS) (26.0 per cent and 5.0 per cent). Age, sex and breed were shown to be significant risk factors, and an interaction between age and sex was discovered. The study indicated a sex ratio reversal in the prevalence of RS - the probability of females having RS increased with advancing age, while the probability for males was fairly constant.     

Effect of cellobiose supplementation on in vitro fermentation activity and bacterial numbers of porcine inocula

In this in vitro study, the modified Hohenheim gas test (HGT) was applied to determine fermentation activity and bacterial composition of pig's faecal microbial inoculum using different concentrations of cellobiose. Incubation procedures included normal buffered and osmotic stress conditions (elevated medium salinity). After 24 hr of fermentation, production of gas, ammonia and short‐chain fatty acid (SCFA) was measured, and the gene copy numbers of total bacteria, Lactobacillus spp., Bifidobacterium spp., Roseburia spp., Clostridium Cluster IV spp. and Enterobacteriaceae were analysed using real‐time polymerase chain reaction. There was a significant reduction in gas production after 24 hr when comparing osmotic stress conditions with normal buffered conditions. Under osmotic stress, increasing cellobiose concentrations linearly increased gas production (p < .001), while ammonia, acetic acid and isobutyric acid concentrations decreased (p < .001, p = .012, p = .035 respectively). Under normal buffered conditions, Roseburia spp. gene copies linearly increased with increasing cellobiose concentrations (p = .048). Lactobacillus spp. and Bifidobacterium spp. numbers were higher under osmotic stress (p < .001) compared to normal conditions. Results might point towards a positive impact of cellobiose supplementation on gut health especially under osmotic stress conditions.     

Untersuchungen zur Erstellung und genetischen Charakterisierung von Rhderchimären

Inhalt: Rinderchimären wurden durch Aggregation geteilter Embryonen unterschiedlicher Rassen im 16- bis 32-Blastomerenstadium erstellt. Nach Transfer von insgesamt 25 chimären Embryonen wurden neun (36%) Kälber geboren, von denen vier = 44,4% chimär waren. Der Nachweis des Chimärismus erfolgte durch Blutgruppenfaktoren, Chromosomenstruktur, Fellpigmentierung und Rückkreuzungen. Im einzelnen konnten durch die Blutgruppenfaktoren zwei = 22,2%, über die Chromosomenstruktur ein = 11,1% und durch die Fellfarbe drei = 33,3% Tiere als chimär erkannt werden. Zwei Kälber, die in ihrem äuβeren Erscheinungsbild die Ausgangsrassen Angler und Schwarzbunt repräsentierten, besaßen identische Blutgruppen. Durch Rückkreuzungen mit zwei chimären Bullen wurde erstmals ein Chimärismus der Keimzellen nachgewiesen .
Contents: Investigations on the production and genetic characterisation of chimaeric cattle
Cattle chimaeras were produced by aggregation of split embryos from different breeds between 16- to 32-cell stage. Altogether 9 (36%) out of 25 transferred chimaeric embryos developed to term of which four proved to be chimaeric. In order to confirm chimaerism blood groups, chromosome structure and coat colour pigmentation were determined and back-crossings were performed. Evidence for chimaerism was given by blood groups (2 = 22,2%), chromosome structure (1 = 11,1%) and coat colour pigmentation (3 = 33,3%). Two calves showing different coat colour pigmentation patterns of either the Angler or the Frisian appeared to have identical chimaeric blood group compositions. By back-crossings of two chimaeric bulls germ cell chimaerism could be demonstrated for the first time .