Quantitative Accuracy of the Simplified Strong Ion Equation to Predict Serum pH in Dogs

Background

Electrochemical approach to the assessment of acid‐base states should provide a better mechanistic explanation of the metabolic component than methods that consider only pH and carbon dioxide.

Hypothesis/Objectives

Simplified strong ion equation (SSIE), using published dog‐specific values, would predict the measured serum pH of diseased dogs.

Animals

Ten dogs, hospitalized for various reasons.

Methods

Prospective study of a convenience sample of a consecutive series of dogs admitted to the Massey University Veterinary Teaching Hospital (MUVTH), from which serum biochemistry and blood gas analyses were performed at the same time. Serum pH was calculated (Hcal+) using the SSIE, and published values for the concentration and dissociation constant for the nonvolatile weak acids (A_tot and K _a), and subsequently Hcal+ was compared with the dog''s actual pH (Hmeasured+). To determine the source of discordance between Hcal+ and Hmeasured+, the calculations were repeated using a series of substituted values for A_tot and K _a.

Results

The Hcal+ did not approximate the Hmeasured+ for any dog (P = 0.499, r ² = 0.068), and was consistently more basic. Substituted values A_tot and K _a did not significantly improve the accuracy (r ² = 0.169 to <0.001). Substituting the effective SID (Atot−[HCO3−]) produced a strong association between Hcal+ and Hmeasured+ (r ² = 0.977).

Conclusions and clinical importance

Using the simplified strong ion equation and the published values for A_tot and K _a does not appear to provide a quantitative explanation for the acid‐base status of dogs. Efficacy of substituting the effective SID in the simplified strong ion equation suggests the error lies in calculating the SID.     

Effect of Chronic Administration of Phenobarbital,or Bromide,on Pharmacokinetics of Levetiracetam in Dogs with Epilepsy

Background

Levetiracetam (LEV) is a common add‐on antiepileptic drug (AED) in dogs with refractory seizures. Concurrent phenobarbital administration alters the disposition of LEV in healthy dogs.

Hypothesis/Objectives

To evaluate the pharmacokinetics of LEV in dogs with epilepsy when administered concurrently with conventional AEDs.

Animals

Eighteen client‐owned dogs on maintenance treatment with LEV and phenobarbital (PB group, n = 6), LEV and bromide (BR group, n = 6) or LEV, phenobarbital and bromide (PB–BR group, n = 6).

Methods

Prospective pharmacokinetic study. Blood samples were collected at 0, 1, 2, 4, and 6 hours after LEV administration. Plasma LEV concentrations were determined by high‐pressure liquid chromatography. To account for dose differences among dogs, LEV concentrations were normalized to the mean study dose (26.4 mg/kg). Pharmacokinetic analysis was performed on adjusted concentrations, using a noncompartmental method, and area‐under‐the‐curve (AUC) calculated to the last measured time point.

Results

Compared to the PB and PB–BR groups, the BR group had significantly higher peak concentration (C _max) (73.4 ± 24.0 versus 37.5 ± 13.7 and 26.5 ± 8.96 μg/mL, respectively, P < .001) and AUC (329 ± 114 versus 140 ± 64.7 and 98.7 ± 42.2 h*μg/mL, respectively, P < .001), and significantly lower clearance (CL/F) (71.8 ± 22.1 versus 187 ± 81.9 and 269 ± 127 mL/h/kg, respectively, P = .028).

Conclusions and Clinical Importance

Concurrent administration of PB alone or in combination with bromide increases LEV clearance in epileptic dogs compared to concurrent administration of bromide alone. Dosage increases might be indicated when utilizing LEV as add‐on treatment with phenobarbital in dogs.     

Clinical Features and Outcome of Dogs with Epiglottic Retroversion With or Without Surgical Treatment: 24 Cases

Background

Published information describing the clinical features and outcome for dogs with epiglottic retroversion (ER) is limited.

Hypothesis/Objectives

To describe clinical features, comorbidities, outcome of surgical versus medical treatment and long‐term follow‐up for dogs with ER. We hypothesized that dogs with ER would have upper airway comorbidities and that surgical management (epiglottopexy or subtotal epiglottectomy) would improve long‐term outcome compared to medical management alone.

Animals

Twenty‐four client‐owned dogs.

Methods

Retrospective review of medical records to identify dogs with ER that underwent surgical or medical management of ER.

Results

Dogs with ER commonly were middle‐aged to older, small breed, spayed females with body condition score (BCS) ≥6/9. Stridor and dyspnea were the most common presenting signs. Concurrent or historical upper airway disorders were documented in 79.1% of cases. At last evaluation, 52.6% of dogs that underwent surgical management, and 60% of dogs that received medical management alone, had decreased severity of presenting clinical signs. In dogs that underwent surgical management for ER, the incidence of respiratory crisis decreased from 62.5% before surgery to 25% after surgical treatment. The overall calculated Kaplan–Meier median survival time was 875 days.

Conclusion and clinical importance

Our study indicated that a long‐term survival of at least 2 years can be expected in dogs diagnosed with epiglottic retroversion. The necessity of surgical management cannot be determined based on this data, but dogs with no concurrent upper airway disorders may benefit from a permanent epiglottopexy to alleviate negative inspiratory pressures.     

Pulmonary Vein‐to‐Pulmonary Artery Ratio is an Echocardiographic Index of Congestive Heart Failure in Dogs with Degenerative Mitral Valve Disease

Background

Early recognition of left‐sided congestive heart failure (CHF) in dogs with degenerative mitral valve disease (DMVD) is important because it influences medical therapy, timing of follow‐up, and outcome.

Hypothesis

Pulmonary vein diameter‐to‐pulmonary artery diameter ratio (PV/PA) measured by echocardiography can predict CHF.

Animals

Ninety‐eight client‐owned dogs, 37 controls, and 61 dogs with DMVD.

Methods

Prospective clinical cohort study. History, physical examination and Doppler‐echocardiography were performed. Dogs were classified as International Small Animal Cardiac Health Council class I, II or III. Congestive heart failure was identified in a subset of 56 dogs based on radiographic findings. The PV/PA was measured in bidimensional (2D) and M‐mode by 2 investigators blinded to the radiologists’ conclusions.

Results

Interobserver coefficients of variation for PV/PA acquisition and measurement were <10%. The PV/PA in control dogs was approximately 1 and increased with class of heart failure. The presence of CHF could be best predicted by measuring PV/PA in 2D echocardiography (cut‐off, 1.7; area under the curve, 0.98; CI, 0.97–0.98; P < .001) with a sensitivity of 96% and a specificity of 91%.

Conclusion and clinical importance

The PV/PA is a simple and reproducible echocardiographic variable that increases with class of heart failure and may help discriminate dogs in CHF from asymptomatic dogs with DMVD. Additional studies are required to determine whether PV/PA might provide additional information in the integrated interpretation of Doppler‐echocardiographic indices of left ventricular filling pressures and could be used for rapid assessment of CHF in dogs in a critical care setting.     

RNAi技术在转基因西瓜抗病毒病上的研究与应用

对RNAi技术的概念、研究进展及西瓜病毒病的危害及其发生特点、RNAi技术在西瓜抗病毒病上的研究进展进行了阐述,并对存在的一些问题作了简要探讨与展望。     

茵陈蒿汤加味配合西药治疗犬传染性肝炎的试验研究

为了观察3种治疗方法治疗犬传染性肝炎的疗效并进行对比，选出较好的治疗方案，以提高犬传染性肝炎的治愈率。本研究选宠物医院确诊为犬传染性肝炎的病犬60只，将患犬随机分4组，分别采用茵陈篙汤加味配合西药、单用茵陈篙汤加味、单用西药的治疗方法，并设对照组。结果显示，茵陈篙汤加味配合西药组的治愈率86.67%；茵陈篙汤加味组治愈率73.33%；西药组治愈率66.67%；对照组治愈率为0。试验表明，采用茵陈篙汤加味配合西药治疗犬传染性肝炎的疗效高于其他两种方法，为临床治疗该病提供了确实可行的治疗方法。     

Echocardiography and conventional Doppler examination in clinically healthy adult Cavalier King Charles Spaniels: Effect of body weight,age, and gender,and establishment of reference intervals

ObjectivesThe objectives of this study were (1) to assess the potential effect of body weight (BW), age, and gender on the most commonly used echocardiographic and conventional Doppler variables in a large population of healthy Cavalier King Charles Spaniels (CKCS), and (2) to establish the corresponding reference intervals (RI).Animals134 healthy adult CKCS.MethodsUltrasound examinations were performed by trained observers in awake dogs. M-mode variables included left ventricular (LV) end-diastolic and end-systolic diameters, LV free wall and interventricular septal thicknesses at end-diastole and end-systole, and LV fractional shortening (FS%). The left atrium (LA) and aortic (Ao) diameters were measured using a 2D method, and the LA/Ao was calculated. Pulsed-wave Doppler variables included peak systolic aortic and pulmonary flow velocities, mitral E and A waves, and E/A ratio. Effects of BW, age, and gender on these 15 variables were tested using a general linear model, and RIs were determined by applying the statistical procedures recommended by the Clinical and Laboratory Standards Institute.ResultsA significant BW effect was observed for all variables, except LA/Ao, FS%, and mitral E/A ratio. A significant but negligible effect of gender and age was also observed for 5/15 and 4/15 of the tested variables, respectively. Only the BW effect on M-mode variables was considered as clinically relevant and the corresponding regression-based RIs were calculated.ConclusionsBody weight should be taken into account when interpreting echocardiographic values in CKCS, except for LA/Ao, FS%, and mitral E/A ratio.     

犬瘟热病毒F蛋白分子生物学研究进展

犬瘟热病毒融合蛋白是囊膜糖蛋白,是产生中和抗体的主要保护性抗原,结构相对保守。融合蛋白介导病毒囊膜和细胞膜融合,决定病毒在宿主体内扩散的能力,在病毒的致病性及免疫原性上具有重要作用。因此,对犬瘟热融合蛋白基因及其蛋白的结构和功能进行研究具有重要的意义。本文从蛋白结构、蛋白功能、核酸序列比对等多方面对融合蛋白进行了阐述。