Assessment of glomerular filtration rate with dynamic computed tomography in normal Beagle dogs

The objective of our study was to determine individual and global glomerular filtration rates (GFRs) using dynamic renal computed tomography (CT) in Beagle dogs. Twenty-four healthy Beagle dogs were included in the experiment. Anesthesia was induced in all dogs by using propofol and isoflurane prior to CT examination. A single slice of the kidney was sequentially scanned after a bolus intravenous injection of contrast material (iohexol, 1 mL/kg, 300 mgI/mL). Time attenuation curves were created and contrast clearance per unit volume was calculated using a Patlak plot analysis. The CT-GFR was then determined based on the conversion of contrast clearance per unit volume to contrast clearance per body weight. At the renal hilum, CT-GFR values per unit renal volume (mL/min/mL) of the right and left kidneys were 0.69 ± 0.04 and 0.57 ± 0.05, respectively. No significant differences were found between the weight-adjusted CT-GFRs in either kidney at the same renal hilum (p = 0.747). The average global GFR was 4.21 ± 0.25 mL/min/kg and the whole kidney GFR was 33.43 ± 9.20 mL/min. CT-GFR techniques could be a practical way to separately measure GFR in each kidney for clinical and research purposes.     

Intestinal permeability and absorption in dogs with traumatic injury

The objectives of this study were to assess the feasibility of using urinary recovery of sugars to evaluate intestinal permeability and absorption in dogs with traumatic injury and to determine if intestinal permeability and absorption are altered in dogs with traumatic injury. After a 6-hour fast, a sugar solution containing lactulose, rhamnose, 3-0-methyl-D-glucose, and xylose was administered via nasoesophageal tube. Urine was collected and quantitated over the 6-hour study period via closed collection urinary catheters. Urinary sugar recoveries were measured by high-pressure anion exchange liquid chromatography and pulsed amperometric detection. Urinary sugar recoveries in the trauma group at 24, 48, and 72 hours after trauma were compared to normal controls. In addition, severity of trauma was compared to urinary sugar recoveries. Twelve client-owned dogs with traumatic injury and 6 healthy controls were enrolled in the study. Lactulose recovery and the lactulose:rhamnose recovery ratio were significantly higher in the trauma group at 48 hours but were no longer different from controls by 72 hours. Xylose recovery was significantly higher in the trauma group when compared to controls at 72 hours, whereas 3-O-methyl-D-glucose recovery was significantly lower in the trauma group at 24 hours. The xylose: 3-O-methyl-D-glucose ratio was higher in the trauma group at all time points. Significant correlation was found between severity of trauma and xylose and 3-O-methyl-D-glucose recoveries 24 hours after injury. Results of this study support the hypothesis that intestinal permeability and absorption are altered in dogs with traumatic injury.     

Serum isoamylase values in normal dogs and dogs with exocrine pancreatic insufficiency

Estimations were made of the serum isoamylase values of normal dogs and of dogs with confirmed exocrine pancreatic insufficiency. A statistically significant difference was demonstrated between the two groups in respect of the values of one of the isoamylase fractions measured. Further study has confirmed that canine salivary tissue lacks amylase activity and that the source of the isoamylase fractions was the pancreas.This knowledge has potential value in the diagnosis of canine exocrine pancreatic insufficiency.     

Assessment of the use of RNA quality metrics for the screening of articular cartilage specimens from clinically normal dogs and dogs with osteoarthritis

OBJECTIVE: To assess 2 methods of RNA purification by use of different quality metrics and identify the most useful metric for quality assessment of RNA extracted from articular cartilage from dogs with osteoarthritis. SAMPLE POPULATION: 40 articular cartilage specimens from the femoral heads of 3 clinically normal dogs and 37 dogs with osteoarthritis. PROCEDURES: RNA was extracted from articular cartilage by 2 purification methods. Quality metrics of each sample were determined and recorded by use of a UV spectrophotometer (Spec I; to determine the 260 to 280 nm absorbance ratio [A(260):A(280) ratio]), a second UV spectrophotometer (Spec II; to determine A(260):A(280) and A(260):A(230) absorbance ratios), and a microfluidic capillary electrophoresis analyzer (to determine the ribosomal peak ratio [RR], degradation factor [DF], and RNA integrity number [RIN]). The RNA was extracted from affected (osteoarthritic) articular cartilage and assessed with the same quality metrics. Metric results were compared with visual analysis of the electropherogram to determine the most useful RNA quality metric. RESULTS: No differences in methods of RNA purification were determined by use of quality metrics. The RNA extracted from unaffected (normal) cartilage was of higher quality than that extracted from affected (osteoarthritic) cartilage, as determined by the RIN and Spec II A(260):A(230) ratio. The RIN and RR were the most sensitive metrics for determining RNA quality, whereas the DF was most specific. A significant proportion (32%) of RNA extracted from osteoarthritic articular cartilage specimens was determined as being of low quality. CONCLUSIONS AND CLINICAL RELEVANCE: No single metric provided a completely sensitive and specific assessment of the quality of RNA recovered from articular cartilage.     

Electromyographic and esophagomanometric findings in clinically normal dogs and in dogs with idiopathic megaesophagus.

Electromyography of 12 clinically normal dogs and 7 dogs with idiopathic megaesophagus revealed trains of positive sharp waves in the muscles of facial expression and in the lingual muscles of both groups. Positive waves are usually indicative of motor-unit disease; however, they are clinically insignificant in these muscles. Positive sharp waves were detected in the esophageal muscle of one dog with congenital megaesophagus. Esophageal electromyograms obtained in a dog with congenital megaesophagus and in 2 clinically normal dogs were normal. Resting caudal esophageal sphincter pressure was similar in both clinically normal dogs (mean, 22.3 mm of Hg; range, 15--37 mm of Hg) and in dogs with congenital or acquired idiopathic megaesophagus (mean, 29.6 mm of Hg; range, 20--50 mm of Hg).     

Bronchography in normal dogs

In twenty-one bronchograms from three normal dogs signs were observed which have been associated with early bronchial disease in man. It is concluded that the only reliable signs of bronchographic abnormality in dogs are gross structural changes affecting the bronchi.     

Timing of left heart base descent in dogs with dilated cardiomyopathy and normal dogs.

The identification and assessment of myocardial failure in canine idiopathic dilated cardiomyopathy (DCM) is achieved using a variety of two-dimensional and Doppler echocardiographic techniques. More recently, the availability of tissue Doppler imaging (TDI) has raised the potential for development of new ways of more accurately identifying a disease phenotype. Nevertheless, TDI has not been universally adapted to veterinary clinical cardiology primarily because of the lack of information on its utility in diagnosis. We assessed the application of timing of left heart base descent using TDI in the identification of differences between DCM and normal dogs. The times from the onset of the QRS complex on a simultaneously recorded electrocardiograph to the onset (Q--S'), peak (Q--peak S'), and end (Q--end S') of the systolic velocity peak were measured in the interventricular septum (IVS) and the left ventricular free wall. The duration of S' was also calculated. The Q--S' (FW), Q--end S' (FW), and duration S' (FW) were correlated with ejection fraction in the diseased group (P < 0.05). In addition, Q--S', Q--peak S', Q--end S', and the peak S' velocity were prolonged in the diseased dogs at both the free wall and in the IVS (P < 0.01). The duration of S' was unaffected by disease status. These findings provide insight into the electromechanical uncoupling that occurs in canine DCM and identifies new TDI parameters that can be added to the range of Doppler and echocardiographic parameters used for detecting myocardial failure in the dog.     

Fat absorption in dogs with demodicosis or zinc-responsive dermatosis.

Quantitative absorption of long-chain triglycerides was studied in normal dogs, dogs with demodicosis and dogs which had been successfully treated for zinc-responsive dermatosis. The mean serum triglyceride concentration of dogs treated for zinc-responsive dermatosis was significantly lower than that of normal dogs before (P less than 0.01) and at one hour (P less than 0.01) and two, three and four hours (P less than 0.001) after feeding vegetable oil. No significant difference was detected in the mean serum triglyceride concentration of dogs with demodicosis and normal dogs at any of the sampling times.     

Vertical patellar position in large-breed dogs with clinically normal stifles and large-breed dogs with medial patellar luxation

OBJECTIVE: To further define vertical patellar position, as measured by the ratio of patellar ligament length to patellar length (L:P), in large-breed dogs with clinically normal stifles and compare that to the L:P of large-breed dogs with medial patellar luxation (MPL). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Large-breed dogs (n = 50) with clinically normal stifle joints and 30 large-breed dogs with MPL. METHODS: Large-breed dogs with clinically normal stifle joints or MPL were identified and divided into groups (NORM and MPL, respectively). L:P values were determined for each dog by 4 observers from single lateral stifle radiographs. L:P was compared between NORM and MPL groups and 95% confidence intervals (CIs) were calculated. RESULTS: All 4 observers found a significantly higher L:P (more proximally positioned patella) for the MPL group compared with the NORM group. Overall mean (+/-SEM) L:P were: NORM, 1.71+/-0.020 and MPL, 1.87+/-0.025. The 95% CI was determined to be 1.45-1.97 for the NORM group and 1.57-2.17 for the MPL group. CONCLUSIONS: Large-breed dogs with MPL had a significantly more proximal vertical patellar position compared with large-breed dogs with clinically normal stifles. Large-breed dogs with L:P values >1.97 are considered to have patella alta. CLINICAL RELEVANCE: Proximal displacement of the patella within the femoral trochlear groove may play a role in MPL in large-breed dogs.     

Treatment of clinically normal and cystinuric dogs with 2-mercaptopropionylglycine

In a pharmacokinetic and tolerance study, 2 healthy Beagles were given 13.2 to 39.5 mg of 2-mercaptopropionylglycine (2-MPG)/kg of body weight orally once daily in increasing doses for 3 weeks. A third dog was given 10 mg of 2-MPG/kg of body weight, IV. The drug was well tolerated. After these initial studies, 15 cystinuric dogs were treated with 2-MPG orally once daily for 5 to 45 months and with sodium bicarbonate for urine alkalinization and fluid diuresis. Pharmacokinetic studies were done in 7 dogs on the third day of oral treatment with 2-MPG. After oral administration of 15.6 to 31.3 of 2-MPG/kg of body weight, maximal serum/plasma concentrations were from 28.6 to 76.3/mumol/L after 1 to 3 hours in 6 cystinuric dogs. The mean urinary excretion was 22% (range, 0.3 to 58.9%) of the dose. Ten of 15 cystinuric dogs had no re-formation of uroliths. Of 4 dogs with uroliths at the beginning of treatment, 3 had total urolith dissolution on continuous treatment. During treatment, further growth of the uroliths was inhibited in one dog, and in another dog with re-formed uroliths, they dissolved. We concluded that 2-MPG is well tolerated and promising for treatment of cystinuric dogs, but the pharmacokinetic studies should be expanded to include different dosage regimens, and results of long-term treatment should be evaluated. Our recommendations for treatment of dogs with cystine uroliths include surgical intervention if the dog has urethral obstruction or has dysuria.(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of neutrophil function in dogs with primary ciliary dyskinesia

Compared with neutrophils from healthy dogs, neutrophils from 2 dogs with primary ciliary dyskinesia had increased distance of random migration, but fewer of the neutrophils migrated. The affected dogs had an increase in the numbers of Staphylococcus aureus phagocytized. Lymphocyte blastogenesis in the affected dogs in response to standard mitogens was considered to be normal.     

Feasibility and repeatability of thermal quantitative sensory testing in normal dogs and dogs with hind limb osteoarthritis-associated pain

The objectives of this study were to determine whether thermal quantitative sensory testing (QST) can be performed in client-owned dogs, is repeatable and whether QST differs between normal dogs and dogs with hind limb osteoarthritis (OA). This clinical, prospective, observational study used clinically normal dogs (n = 23) and dogs with OA-associated hind limb pain (n = 9). Thermal QST was performed in standing dogs using a high-powered light source delivered by a previously validated system. Dogs were tested on two occasions, 2 weeks apart. Five tests were performed on each hind limb at each time point. Repeated measures analysis of variance was used to evaluate the effects of leg, time point and OA/normal status on thermal threshold latencies (TTL). Additionally, paired t tests were used to compare the TTL of left and right limbs within groups and between time points.Thermal thresholds were successfully measured in 32 client-owned dogs without prior training. TTL were significantly different between normal and OA dogs (P = 0.012). There was no difference between limbs (P = 0.744) or time periods (P = 0.572), when analyzed by repeated measures analysis of variance, and no interactions between group and limb, visit and limb, or visit and group. In conclusion, thermal thresholds can be measured in client owned dogs with no prior training and are repeatable from week to week. Further data are required to determine if OA results in thermal hypoalgesia as measured at the distal hind limb and whether this is an indication of central sensitization.     

Plasma von Willebrand factor-collagen binding activity in normal dogs and in dogs with von Willebrand's disease.

A sensitive enzyme-linked immunosorbent assay was used for the simultaneous assessment of the amount of von Willebrand factor (vWF) in canine plasma and its ability to bind to canine collagen in vitro. In 60 normal dogs, there was close correlation between the concentration of vWF and its activity as determined by vWF-collagen binding. In 14 dogs with type I expressions of von Willebrand's disease, the ratio of vWF antigen to collagen binding activity was normal or only slightly increased. In 7 dogs with type II expressions of the disease, this ratio was consistently elevated suggesting a significant functional deficiency of the protein. Plasma from 3 dogs with type III von Willebrand's disease had little collagen binding activity because of the severe quantitative deficiency of the protein. The described assay permits the rapid assessment of both the quantity and quality of vWF in a dog. This information is necessary for the detection and characterization of canine von Willebrand's disease, particularly the type II expressions, which cannot be diagnosed by quantitative vWF assays alone.     

Pharmacokinetics of sulphadimidine in normal and febrile dogs

Pharmacokinetic parameters which describe the distribution and elimination of sulphadimidine were determined in normal dogs and dogs in which fever was produced by an intravenous injection of escherichia and staphylococcal species of bacteria. Sulphadimidine was injected as a single intravenous bolus at the dose of 100 mg/kg and the kinetics of the drug were described in terms of the bi-exponential expression: C_p = Ae ^{-α t} + Be ^{-β t} . The distribution half-times of the drug were 1.52 h in the normal and 0.81 h in the febrile dogs. The drug distribution was significantly more rapid ( P < 0.05) in febrile than in normal dogs. Average ± SD values for the half-lives of the drug were 16.2 ± 5.7 h in normal and 16.7 ± 4.7 h in the febrile dogs. The apparent volume of distribution ( V ' _d (area)) was 628 ± 251 ml/kg in the normal dogs, and was not statistically different from 495 ± 144 ml/kg in the febrile dogs. The volume of the central compartment ( V ' _c ) was 445 ± 55 ml/kg in normal dogs and this was significantly higher ( P < 0.01) than the V ' _c of 246 ± 72 ml/kg in the febrile dogs. The body clearance was 22.4 ± 4.8 and 20.2 ± 3.6 ml/hour. kg in the normal and febrile dogs, respectively. The investigation revealed that the dosage regimen of sulphadimidine did not differ significantly between normal and febrile dogs.     

Systemic availability of o,p'-DDD in normal dogs, fasted and fed, and in dogs with hyperadrenocorticism

The systemic availability of o,p'-DDD was studied in 12 normal dogs and seven dogs with pituitary-dependent hyperadrenocorticism (PDH). The drug was given by mouth at 50 mg kg-1 and plasma o,p'-DDD concentrations were determined by gas-liquid chromatography. First, six normal dogs were given the drug three times at intervals of one week in a Latin square pattern. Systemic drug availability was found to be very poor from intact tablets in fasted dogs, better with pure drug dissolved in maize oil given by stomach tube, and best with ground tablets mixed in oil poured on dog food. Then six normal dogs and five with PDH were given one dose of o,p'-DDD as intact tablets in dog food. Systemic drug availability was good in the normal animals and, for unknown reasons, better in dogs with PDH. The half-time of elimination was shorter in dogs with PDH than in normal ones. There was evidence of a gradual rise in plasma o,p'-DDD concentrations in seven dogs with PDH treated with 25 mg kg-1 every 12 hours for 14 or 20 days. The interaction between food and o,p'-DDD probably contributes to the variation in clinical response of dogs treated with the drug. The efficiency of therapy with o,p'-DDD should be improved considerably by administering the drug with food.     

Changes in QRS complex in dogs with normal and exaggerated tidal volumes

The influence of normal and exaggerated ventilation on the QRS was studied in 10 dogs. Peak-to-peak amplitudes of QRS in 4 circumferential unipolar and 2 limb lead ECG were obtained during eupnea and during hyperinflation produced by intermittent positive pressure ventilation or negative extrathoracic pressure. Marked changes were not observed in any lead during eupnea. During hyperinflation to a transpulmonary pressure of 10 mm of Hg (whether by intermittent positive pressure ventilation or negative extrathoracic pressure), voltages decreased in leads I, V10, rV3, and aVF and were variable in leads V3 and V5. Radiography revealed that during the hyperinflation the heart was displaced to the nondependent side of the thorax further from the dependent electrodes and that the heart became generally smaller. Changes in voltage could be attributed to alterations in relationships between the heart and electrodes on the torso surface or to changes in volume conductor properties of the heart and torso.     

Magnetic resonance imaging of the femoral head of normal dogs and dogs with avascular necrosis.

The purpose of this study was to describe the appearance of the femoral head of normal, young, small breed dogs, and dogs with avascular necrosis using low-field (0.3 T) magnetic resonance (MR) imaging. Images of the femoral heads were obtained in the dorsal plane, and included T1-weighted spin-echo, T2-weighted fast spin-echo, fast spin echo-inversion recovery, and fluid attenuated inversion recovery pulse sequences. MR imaging features of the asymptomatic femoral heads and necks included uniform high signal intensity compared with muscle on T1- and T2-weighted images. There was either uniform enhancement or no enhancement on postcontrast T1-weighted images. The MR imaging findings of dogs affected with avascular necrosis differed from those of asymptomatic dogs. Typically, the affected dogs had inhomogeneous intermediate to low-signal intensity within the femoral head and neck compared with muscle on T1-weighted images, inhomogeneous enhancement of the femoral head and/or neck on postcontrast T1-weighted images, and inhomogeneous low- to high- signal intensity within the femoral head and neck on T2-weighted images.