OBJECTIVE To compare dialysate sodium concentration and patient plasma sodium concentration of dogs during intermittent hemodialysis treatments. SAMPLE 211 intermittent hemodialysis treatments performed on 40 client-owned dogs for the management of dialysis-dependent uremia. PROCEDURES Medical records were reviewed to determine the plasma sodium concentration of each dog before and after routine hemodialysis treatments. Associations between detected changes in plasma sodium concentration and dialysate sodium concentration were evaluated by use of Spearman rank correlations and linear regression analysis. RESULTS Significant linear correlations were found between the dialysate sodium concentration and patient sodium concentration. The starting dialysate-to-patient sodium gradient was associated with the strongest correlation to the change in patient sodium concentration at the end of the dialysis session. Modest correlations existed between the dialysate sodium concentration and postdialysis patient sodium concentration as well as between the predialysis dialysate-to-patient sodium gradient and postdialysis dialysate-to-patient sodium gradient. CONCLUSIONS AND CLINICAL RELEVANCE The dialysate sodium concentration was correlated with the patient sodium concentration in dogs, and the dialysate-to-patient sodium gradient could be used to further refine this association to predict the postdialysis patient sodium concentration and potentially manage dysnatremia during hemodialysis. Prospective studies should be performed to determine how these associations can be used to correct aberrations as well as to avoid unwanted alterations in patient sodium concentrations.

OBJECTIVE To assess the use of contrast-enhanced ultrasonography (CEUS) of the hepatic vein for the detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs. ANIMALS 6 healthy Beagles. PROCEDURES A prospective study was conducted. A catheter was surgically placed in the portal vein of each dog. Hypertension was induced by intraportal injection of microspheres (10 to 15 mg/kg) at 5-day intervals via the catheter. Microsphere injections were continued until multiple acquired portosystemic shunts were created. Portal vein pressure (PVP) was measured through the catheter. Contrast-enhanced ultrasonography was performed before and after establishment of hypertension. Time-intensity curves were generated from the region of interest in the hepatic vein. Perfusion variables measured for statistical analysis were hepatic vein arrival time, time to peak, time to peak phase (TTPP), and washout ratio. The correlation between CEUS variables and PVP was assessed by use of simple regression analysis. RESULTS Time to peak and TTPP were significantly less after induction of portal hypertension. Simple regression analysis revealed a significant negative correlation between TTPP and PVP. CONCLUSIONS AND CLINICAL RELEVANCE CEUS was useful for detecting hemodynamic changes associated with experimentally induced portal hypertension in dogs, which was characterized by a rapid increase in the intensity of the hepatic vein. Furthermore, TTPP, a time-dependent variable, provided useful complementary information for predicting portal hypertension. IMPACT FOR HUMAN MEDICINE Because the method described here induced presinusoidal portal hypertension, these results can be applied to idiopathic portal hypertension in humans.

The objectives of this study were to establish a reference interval for canine cerebrospinal fluid lactate (CSFL) and to compare CSFL and plasma lactate (PL) concentrations in anesthetized dogs with and without intracranial disease. Using a prospective study, canine blood and cerebrospinal fluid were collected for lactate analysis in 11 dogs with intracranial disease after undergoing magnetic resonance imaging (MRI) (Group ID-MRI), in 10 healthy dogs post-MRI (Group H-MRI), and in 39 healthy dogs after induction of anesthesia (Group H-Sx). Dogs were anesthetized for the procedures using different anesthetic protocols. Neurological scores (NS) and sedation scores (SS) were assessed pre-anesthesia in ID-MRI dogs. The CSFL reference interval [90% confidence interval (CI) for lower and upper limits] was 1.1 (1.0 to 1.2) to 2.0 (2.0 to 2.1) mmol/L. Mean ± SD CSFL concentrations were: ID-MRI, 2.1 ± 0.8; H-MRI, 1.6 ± 0.4; and H-Sx, 1.6 ± 0.2 mmol/L. There was a tendency for higher CSFL in dogs in the ID-MRI group than in those in the H-MRI or H-Sx groups (P = 0.12). There was agreement between CSFL and PL in ID-MRI dogs (P = 0.007), but not in dogs in H-MRI (P = 0.5) or H-Sx (P = 0.2). Of the ID-MRI dogs, those with worse NS had higher CSFL (r (2) = 0.44). The correlation between CSFL and PL in dogs with intracranial disease and between worse NS and higher CSFL warrants further investigation into the use of CSFL and PL for diagnostic and prognostic purposes.

A matched case-control study was conducted to evaluate dietary components and exercise patterns as potential risk factors for osteochondritis dissecans in dogs. A telephone interview, with a standard questionnaire and protocol, was used to collect data on dietary intake of calories and nutrients and on the usual amounts and types of exercise of each dog. Thirty-one dogs with osteochondritis dissecans and 60 controls were matched on the basis of breed, sex, and age. Using a conditional logistic regression model, high dietary calcium, playing with other dogs, and drinking well water (rather than city water) were associated with increased risk of osteochondritis dissecans. Feeding of specialty dry dog foods was associated with decreased risk.

A survey of 1,965 equine colic cases was conducted from August 1985 to July 1986 at 10 equine referral centers located throughout the United States. The purpose of this study was to develop and validate a multivariable model for the need for surgery. Two-thirds of the cases were randomly selected for model development (1,336), whereas the remaining cases (629) were used only for subsequent validation of the model. If a lesion requiring surgical correction was found at either surgery or necropsy, the case for the horse was classified as surgical, otherwise the case was classified as medical. Only variables that were significant (P < 0.05) in an initial bivariable screening procedure were considered in the model development. Because of the large number of missing values in the data set, only variables for which there were < 400 missing values were considered in the multivariable analysis. A multivariable logistic regression model was constructed by use of a stepwise algorithm. The model used 640 cases and included variables: rectal findings, signs of abdominal pain, peripheral pulse strength, and abdominal sounds. The likelihood ratio for surgery was calculated for each horse in the validation data set, using the logistic regression equation. Using Bayes theorem, the posttest probability was calculated, using the likelihood ratio as the test odds and the prevalence of surgery cases (at each institution) as an estimate of the pretest odds. A Hosmer-Lemeshow goodness-of-fit X2 statistic indicated that the model fit the validation data set poorly, as demonstrated by the large X2 value of 26.7 (P < 0.001). However, when the expected proportion of surgical cases was compared with the observed proportion of surgical cases in each of 10 increments of risk, the model's performance appeared satisfactory.

A prospective cohort study was undertaken in a farrow-to-farrow swine herd to describe patterns of pneumonia, and to identify host risk factors associated with the extent of pneumonic lesions in 2 weight groups of slaughter swine. The risk of coughing and pneumonic lesions increased with increasing age of pigs within the herd (P < 0.0001). The age-specific prevalence of pneumonic lesions was low (2.7%) in pigs < 16 weeks old at slaughter, but increased rapidly when pigs were between 16 and 22 weeks old (8.6 to 67.9%). After 22 weeks, the prevalence remained relatively constant at about 80%. Associations between possible risk factors and pneumonia were investigated by use of multiple-regression models. Age at weaning (< 24 days) and birth weight (< 1 kg) exerted small, but significant (P < 0.002), effects on the extent of pneumonic lesions in pigs slaughtered at 30 to 50 kg live weight. For pigs slaughtered at 90 to 110 kg, pneumonic lesions were more extensive (P = 0.007) in pigs sired by Yorkshire boars than pigs sired by non-Yorkshire sires (Duroc, Hampshire, Chester White, or American Spotted). Other host factor variables including weaning weight and clinical diseases (atrophic rhinitis, diarrhea, and arthritis) were not associated with pneumonia extent in either weight group. Higher pneumonia percentages were also associated with reduced growth rates in the grower/finisher phase. Pigs sired by Yorkshire boars grew significantly (P < 0.0001) more slowly from entry into shed 2 (mean, 38 kg) until about the time of exit (mean, 92 kg) than pigs sired by other breeds (747 g/d and 795 g/d, respectively).

Samples of pleural fluid from 20 horses with effusive pleural diseases of various causes were evaluated; samples from 19 horses were used for the study. There were differences for pH (P = 0.001) and partial pressure of oxygen (P(O2)) between arterial blood and nonseptic pleural fluid (P = 0.0491), but there were no differences for pH, P(O2), partial pressure of carbon dioxide (P(CO2)) and concentrations of bicarbonate (HCO3-), lactate, and glucose between venous blood and nonseptic pleural fluid. Paired comparisons of venous blood and nonseptic pleural fluid from the same horse indicated no differences. There were differences (P = 0.0001, each) for pH, P(O2), P(CO2), and concentrations of HCO3- between arterial blood and septic pleural fluid. Differences also existed for pH (P = 0.0001), P(CO2) (P = 0.0003), and concentrations of HCO3- (P = 0.0001), lactate (P = 0.0051), and glucose (P = 0.0001) between venous blood and septic pleural fluid. Difference was not found for values of P(O2) between venous blood and septic pleural fluid, although 4 samples of septic pleural fluid contained virtually no oxygen. Paired comparisons of venous blood and septic pleural fluid from the same horse revealed differences (P < 0.05) for all values, except those for P(O2). These alterations suggested functional and physical compartmentalization that separated septic and healthy tissue. Compartmentalization and microenvironmental factors at the site of infection should be considered when developing therapeutic strategies for horses with septic pleural disease.

A prospective study of 65 research beagles kept in a rabies-free environment was undertaken to determine the duration of immunity after they received licensed rabies vaccines. The eventual goal was to extend mandated rabies booster intervals to 5 or 7 years and help reduce the risk of vaccine-associated adverse events. Three groups of dogs were vaccinated with 1 of 2 commercial rabies vaccines or saline at 12 and 15 weeks of age. Beginning 5 years 5 months later, vaccinated and unvaccinated dogs were challenged with virulent rabies virus and observed for 90 days over a series of 3 trials. Humoral and cellular immune responses were examined by serology and flow cytometry. Brain tissue from all challenged dogs was tested for rabies virus. Challenge trial 1 was confounded due to insufficiently virulent virus. In trials 2 and 3 virulent challenge provided 100% mortality in controls. Vaccinate survival was 80% (4/5) after 6 years 7 months, 50% (6/12) after 7 years 1 month, and 20% (1/5) after 8years 0 months. Antibody responses 12 days post-challenge correlated strongly with survival. In a separate non-challenge trial, administration of either a recombinant or a killed rabies vaccine demonstrated memory antibody responses 6 years 1 month after initial vaccination compared with unvaccinated controls. Our data demonstrated that i) duration of immunity to rabies in vaccinated dogs extends beyond 3 years; ii) immunologic memory exists even in vaccinated dogs with serum antibody titer < 0.1 IU/mL; and iii) non-adjuvanted recombinant rabies vaccine induces excellent antibody responses in previously vaccinated dogs 14 days after administration.

OBJECTIVE To evaluate repeatability and reproducibility of muscle condition score (MCS) in dogs with various degrees of muscle loss; to compare MCS, muscle ultrasonographic measurements, and quantitative magnetic resonance (QMR) measurements; and to identify cutoff values for ultrasonographic measurements of muscle that can be used to identify dogs with cachexia and sarcopenia. ANIMALS 40 dogs of various age, body condition score (BCS), and MCS. PROCEDURES A prospective cross-sectional study was conducted. Body weight, BCS, QMR measurements, thoracic radiographic measurements, and muscle ultrasonographic measurements were assessed once in each dog. The MCS for each dog was assessed 3 separate times by 4 separate raters. RESULTS For the MCS, overall κ for interrater agreement was 0.50 and overall κ for intrarater agreement ranged from 0.59 to 0.77. For both interrater and intrarater agreement, κ coefficients were higher for dogs with normal muscle mass and severe muscle loss and lower for dogs with mild and moderate muscle loss. The MCS was significantly correlated with age (r = −0.62), vertebral epaxial muscle score (VEMS; r = 0.71), forelimb epaxial muscle score (FLEMS; r = 0.58), and BCS (r = 0.73), and VEMS was significantly correlated (r = 0.84) with FLEMS. Cutoff values for identification of mild muscle loss determined by use of VEMS and FLEMS were 1.124 and 1.666, respectively. CONCLUSIONS AND CLINICAL RELEVANCE MCS had substantial repeatability and moderate reproducibility for assessment of muscle mass in dogs. Prospective studies of MCS, VEMS, and FLEMS for assessment of muscle mass in dogs are warranted.