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Abstract Background Fibroblast growth factor (FGF)‐23 is increased first in the sequence of changes associated with chronic kidney disease (CKD)‐mineral and bone disorder. Thus, its measurement may serve as a predictive indicator of incident hyperphosphatemia. Objectives To investigate whether serum FGF‐23 concentration in normophosphatemic dogs with CKD is associated with the risk of the subsequent development of hyperphosphatemia and CKD progression. Animals Forty‐two normophosphatemic dogs with CKD. Methods Blood samples and medical records were retrospectively investigated. Hyperphosphatemia was defined as a serum phosphorous concentration >5.0 mg/dL. Progression was defined as a >1.5‐fold increase in serum creatinine concentration. The time periods and hazard ratios for these outcomes were assessed using Kaplan‐Meier analysis, log‐rank test, and univariate Cox regression analysis. The variables associated with the outcomes in the univariate analysis were included in the multivariate Cox regression model with backward selection. Results Serum FGF‐23 concentration >528 pg/mL was associated with a shorter time to development of hyperphosphatemia (P

Background: Ivabradine is used to treat tachycardia; unlike atenolol, it does not affect blood pressure or myocardial contractility. This study compared the impact of ivabradine and atenolol on heart rate (HR) and HR variability (HRV) during a 24 h period, feeding and sleeping times, via a Holter electrocardiogram in healthy cats. We hypothesised that ivabradine and atenolol would lower the HRs equally well, even at times of excitement and rest, such as during feeding and sleep; that ivabradine, unlike atenolol, would have an effect onHRV. Methods: Five clinically healthy cats were used in the prospective blinded crossover study receiving 3 days of ivabradine (0.30mg/kg per os twice daily) followed by atenolol (6.25 mg/cat per os twice daily, range 1.3-2.0 mg/kg) or receiving atenolol followed by ivabradine. A placebo period was initiated before the start of the crossover test, data obtained during that period were used as a baseline (BL). Evaluation parameters included HR and HRV, for the whole 24 h period and for feeding and sleeping times, comparing the effect of ivabradine and atenolol with BL. Results: The HR for the whole 24 h, feeding and sleeping times, were significantly lower with ivabradine and atenolol, compared to BL (p < 0.05). The HRV for the whole 24 h and sleeping time were significantly higher after ivabradine compared with BL and after atenolol. Conclusions: In healthy cats, ivabradine and atenolol significantly reduced the HR regardless of excitement and rest; their effects were comparable. Ivabradine significantly increased HRV in comparison to BL whereas atenolol did not. [ABSTRACT FROM AUTHOR]

Information regarding the pharmacokinetics of oral sildenafil in dogs with pulmonary hypertension is limited. In this study, we examined the pharmacokinetics of oral sildenafil in a canine model of chronic embolic pulmonary hypertension (CEPH). The CEPH model was developed by repeatedly injecting microspheres into the pulmonary arteries. The pharmacokinetics of oral sildenafil at 1, 2 and 4 mg/kg was evaluated using four dogs with pulmonary hypertension in the fasted state. The plasma concentrations of sildenafil were determined using high-performance liquid chromatography, and pharmacokinetic parameters were calculated using a noncompartmental analysis. Sildenafil was well tolerated in this study. Proportional increments in the maximum plasma concentration and area under the curve extrapolated to infinity at drug doses of 1, 2 and 4 mg/kg were detected using a power model analysis. No significant differences were observed among the three doses in the time to maximum plasma concentration. The mean residence time and elimination half-life were slightly but significantly higher at a dose of 4 mg/kg than at a dose of 1 mg/kg. [ABSTRACT FROM AUTHOR]

Basic information related to the association between right heart echocardiographic parameters and invasive pulmonary artery pressure (PAP) in dogs with pulmonary hypetension (PH) is scarce. The aim of this study was to examine the association between conventional right heart echocardiographic parameters and invasive PAP by right heart catheterization (RHC) before and after PH. Five female beagle dogs regarded as clinically healthy were used. Echocardiography and RHC were conducted before and after creating chronic embolic pulmonary hypertension (CEPH) models. The acceleration time to ejection time ratio in pulmonary artery flow profile (AT/ET), the ratio of the pulmonary artery and aortic diameter in diastole (PA/Ao), the right pulmonary artery distensibility index by M-mode method (RPAD M-mode), the normalized right ventricular internal diameter in diastole (RVIDdn), and the normalized tricuspid annular plane systolic excursion (TAPSEn) were correlated with the invasive systolic PAP (sPAP), mean PAP (mPAP) and diastolic PAP (dPAP). Multiple linear regression analysis identified AT/ET and RVIDdn as independent predictors of sPAP, PA/Ao and RVIDdn as independent predictors of mPAP, and PA/Ao and RPAD M-mode as independent predictors of dPAP. AT/ET and PA/Ao had high sensitivity and specificity for predicting CEPH. In conclusion, AT/ET, PA/Ao, RPAD M-mode, RVIDdn and TAPSEn were significantly correlated with invasive PAP and alterations in PA/Ao or AT/ET might enable clinicians to predict PH, even if tricuspid regurgitation is not observed. [ABSTRACT FROM AUTHOR]