Compensatory load redistribution in naturally occurring osteoarthritis of the elbow joint and induced weight-bearing lameness of the forelimbs compared with clinically sound dogs

The current study investigated the compensatory load redistribution due to osteoarthritis of the elbow joint using ground reaction forces of all four legs, simultaneously measured on a treadmill with integrated force plates. Three groups of dogs were used: the first group was clinically sound; the second group suffered from a naturally occurring osteoarthritis of the elbow joint, and a reversible lameness was induced in the third group. The naturally occurring osteoarthritis resulted in a compensatory gait pattern to reduce the stress on the affected limb. The load was reduced on the lame limb and increased on the contralateral hindlimb. The symmetry index indicated a weight-shift to the contralateral forelimb and diagonal hindlimb, which resulted in a more balanced weight distribution than in normal dogs. Dogs with induced lameness showed comparable but less pronounced alterations. These results suggested that forelimb lameness could lead to overload on non-affected extremities and the vertebral spine.     

Short-term outcome after total elbow arthroplasty in dogs with severe, naturally occurring osteoarthritis

OBJECTIVE: To evaluate limb function in client-owned dogs before and after total elbow arthroplasty (TEA) for severe, naturally occurring osteoarthritis (OA). STUDY DESIGN: Prospective clinical evaluation comparing limb function before and after surgery. ANIMALS: Twenty adult, large breed dogs with elbow OA. METHODS: Physical, radiographic, and force platform gait examinations were performed on all dogs before surgery. TEA was performed, and examinations were repeated at 3, 6, and 12 months after surgery. Pre- and postoperative findings were compared. RESULTS: TEA led to a satisfactory outcome in 16 dogs. In dogs with a satisfactory outcome, function in the operated limb increased over time, with mean peak vertical force (PVF) and vertical impulse (VI) 1 year after surgery being nearly twice the presurgical value. Serious complications encountered included infection (n = 2), luxation (n = 1), and fracture of the humeral condyle (n = 1). CONCLUSIONS: Although TEA, as presented, has significant limitations, it can be successfully performed in dogs with naturally occurring elbow OA. Improvements in technique and implant design should lead to improved prognosis. CLINICAL RELEVANCE: Based on 1-year data, TEA can be successfully performed in dogs and should be considered as a treatment alternative for adult dogs with lameness from severe OA of the elbow joint.     

Hemostatic changes in dogs with naturally occurring sepsis

Sepsis is a frequent source of morbidity and mortality in critically ill patients. The goal of this case control study was to measure hemostatic changes in dogs with naturally occurring sepsis. Blood was collected within 24 hours of admission from 20 dogs that fulfilled the criteria for sepsis. Sepsis was defined as histologic or microbiological confirmation of infection and 2 or more of the following criteria: hypo- or hyperthermia, tachycardia, tachypnea, or leukopenia, leukocytosis, or > 3% bands. Culture and sensitivities were performed on appropriate samples from all septic dogs. Twenty-eight control dogs were enrolled on the basis of normal results of physical examination, CBC, serum biochemistry, and coagulation profile. Plasma samples were analyzed for prothrombin time (PT), partial thromboplastin time (PTT), fibrin(ogen) degradation products (FDP), D-dimer (DD) concentrations, antithrombin (AT) activity, and protein C (PC) activity. Data were compared between groups by chi-square or independent t-tests. PC (P < .001) and AT (P < .001) activities were significantly lower in dogs with sepsis compared to controls. Dogs with sepsis had significantly higher PT (P = .007), PTT (P = .005), D-dimer (P = .005), and FDP (P = .001) compared to controls. Platelet counts were not significantly different between groups. Ten of the 20 septic dogs (50%) died, but no association was identified between any of the measured variables and outcome. These findings are consistent with previous studies in animals with experimentally induced disease and in clinical studies of humans. On the basis of these results, further investigation of the role of AT and PC in canine sepsis is warranted.     

The effect of weight loss on lameness in obese dogs with osteoarthritis

This paper describes the effect of weight loss on lameness in obese dogs with osteoarthritis (OA). Fourteen obese client-owned dogs with clinical and radiographic signs of OA participated in an open prospective clinical trial. After a screening visit and a visit for collection of baseline data, the dogs were fed a restricted-calorie diet over a study period of 16 weeks that incorporated six follow-up visits. At each visit, body weight and pelvic circumference were measured and severity of lameness was assessed using a numeric rating scale (NRS), a visual analogue scale (VAS) and kinetic gait analysis. This is the first study to assess both subjectively and objectively, the effect of weight loss alone on lameness in obese dogs with OA. The results indicate that body weight reduction causes a significant decrease in lameness from a weight loss of 6.10% onwards. Kinetic gait analysis supported the results from a body weight reduction of 8.85% onwards. These results confirm that weight loss should be presented as an important treatment modality to owners of obese dogs with OA and that noticeable improvement may be seen after modest weight loss in the region of 6.10 – 8.85% body weight.     

Anti-insulin antibodies in dogs with naturally occurring diabetes mellitus

The presence of anti-insulin antibodies was determined by ELISA in serum samples from 30 diabetic dogs receiving bovine insulin therapy and 30 normoglycaemic dogs. Twenty of the diabetic dogs had significant reactivity to both bovine (heterologous) and porcine (homologous) insulin compared to control dogs. In contrast there was no significant difference between the two populations in reactivity to canine distemper virus (CDV) or canine thyroglobulin. The high degree of correlation between anti-bovine insulin and anti-porcine insulin antibodies suggested cross-reactivity which was confirmed by performing a competition ELISA, with antibody binding to bovine insulin inhibited by pre-incubating serum with porcine insulin. The insulin B-chain, rather than the A-chain was the most reactive component of the insulin molecule although in some cases, diabetics with antibody reactivity to whole insulin protein showed minimal reactivity to the individual subunits. The data suggest that treatment of diabetic dogs with bovine insulin can lead to anti-insulin antibody production. These antibodies cross-react with homologous insulin and recognise conformational as well as linear epitopes.     

Effects of feeding a high omega‐3 fatty acids diet in dogs with naturally occurring osteoarthritis

The aim of this randomized, placebo‐controlled and double‐blinded trial was to compare the effect of a veterinary therapeutic diet (VTD) rich in omega‐3 fatty acids (omega‐3) from fish origin to a regular diet used as control (CTR) over a period of 13 weeks in dogs afflicted by naturally occurring osteoarthritis (OA). Thirty privately owned dogs were selected. Dogs had lameness confirmed by an orthopaedic examination, had stifle/hip OA and had locomotor disability based on the peak of the vertically oriented ground reaction force (PVF) measured using a force platform. At Baseline, all owners were asked to determine 2–5 activities of daily living that were the most impaired. Activities were scores (0–4) in accordance with severity using case‐specific outcome measures (CSOM). The PVF was also measured. Dogs (15/group) were then randomly assigned to receive either the CTR or the VTD. The CSOM was completed twice weekly. The recording of PVF was repeated at Week 7 and 13. The VTD‐fed dogs showed a significantly higher PVF at Week 7 (p < 0.001) and at Week 13 (p < 0.001) when compared to Baseline. From Baseline to Week 13, VTD‐fed dogs had a mean (± SD) change in PVF recording of 3.5 ± 6.8% of body weight (%BW) compared with 0.5 ± 6.1%BW (p = 0.211) in CTR‐fed dogs. This change in primary outcome was consistent with an effect size of 0.5. Conversely, dogs fed the CTR did not show significant change in PVF measurements. At the end of the study, the CSOM was significantly decreased (p = 0.047) only in VTD fed dogs. In lame OA dogs, a VTD that contains high level of omega‐3 from fish origin improved the locomotor disability and the performance in activities of daily living. Such nutritional approach appears interesting for the management of OA.     

Effect of weight reduction on clinical signs of lameness in dogs with hip osteoarthritis

OBJECTIVE: To determine the effect of weight reduction on clinical signs of lameness among overweight dogs with clinical and radiographic signs of hip osteoarthritis. DESIGN: Nonblinded prospective clinical trial. ANIMALS: 9 client-owned dogs with radiographic signs of hip osteoarthritis that weighed 11 to 12% greater than their ideal body weight and were examined because of hind limb lameness. PROCEDURE: Dogs were weighed, and baseline body condition, hind limb lameness, and hip function scores were assigned. Severity of lameness was scored using a numerical rating scale and a visual analogue scale. Dogs were fed a restricted-calorie diet, with amount of diet fed calculated to provide 60% of the calories needed to maintain the dogs' current weights. Evaluations were repeated midway through and at the end of the weight-loss period. RESULTS: Dogs lost between 11 and 18% of initial body weight. Body weight, body condition score, and severity of hind limb lameness were all significantly decreased at the end of the weight-loss period. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in overweight dogs with hind limb lameness secondary to hip osteoarthritis, weight reduction alone may result in a substantial improvement in clinical lameness.     

Acid-base and hormonal abnormalities in dogs with naturally occurring diabetes mellitus

OBJECTIVE: To examine acid-base and hormonal abnormalities in dogs with diabetes mellitus. DESIGN: Cross-sectional study. ANIMALS: 48 dogs with diabetes mellitus and 17 healthy dogs. PROCEDURES: Blood was collected and serum ketone, glucose, lactate, electrolytes, insulin, glucagon, cortisol, epinephrine, norepinephrine, nonesterified fatty acid, and triglyceride concentrations were measured. Indicators of acid-base status were calculated and compared between groups. RESULTS: Serum ketone and glucose concentrations were significantly higher in diabetic than in healthy dogs, but there was no difference in venous blood pH or base excess between groups. Anion gap and strong ion difference were significantly higher and strong ion gap and serum bicarbonate concentration were significantly lower in the diabetic dogs. There were significant linear relationships between measures of acid-base status and serum ketone concentration, but not between measures of acid-base status and serum lactate concentration. Serum insulin concentration did not differ significantly between groups, but diabetic dogs had a wider range of values. All diabetic dogs with a serum ketone concentration > 1,000 micromol/L had a serum insulin concentration < 5 microU/mL. There were strong relationships between serum ketone concentration and serum glucagon-insulin ratio, serum cortisol concentration, and plasma norepinephrine concentration. Serum beta-hydroxybutyrate concentration, expressed as a percentage of serum ketone concentration, decreased as serum ketone concentration increased. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that ketosis in diabetic dogs was related to the glucagon-insulin ratio with only low concentrations of insulin required to prevent ketosis. Acidosis in ketotic dogs was attributable largely to high serum ketone concentrations.     

Kidney transplantation in dogs with naturally occurring end-stage renal disease

Renal allografts were performed between unrelated donors and 15 dogs with naturally occurring end-stage renal disease. Donor selection was based on compatible dog erythrocyte antigen typing and cross-matching. An immunosuppressive protocol consisting of rabbit antidog antithymocyte serum, cyclosporin-A, azathioprine, and prednisone was used to control postoperative rejection of the donated kidney. Although seven animals died because of technical failures or rejection episodes, a median survival time of eight months has been achieved, with two dogs living for longer than five years after surgery. Long-term survivors have died from a variety of problems not related to renal allograft rejection.     

Plasma antioxidant capacity in dogs with naturally occurring heart diseases

The aim of the study was to compare the plasma levels of antioxidants by measuring total antioxidant activity (TAS) and ferric reducing ability of the plasma (FRAP) in healthy dogs and in those that are suffering from dilated cardiomyopathy (DCM) or from mitral endocardiosis (ME). Dogs with echocardiographically diagnosed ME (10 dogs) as well as DCM (23 dogs) were sampled. Of dogs with DCM, eight having DCM with sinus rhythm (SR) were included in the DCM-SR group and 15 having DCM with atrial fibrillation (AF) in the DCM-AF group. Total antioxidant levels measured by TAS assay differed neither significantly between the cardiac patients and the control group nor between the heart disease groups. Ferric reducing ability of the plasma in animals with cardiac disease was significantly higher than in the control animals, and the difference was also significant in between the two DCM groups. However, the differences between the antioxidant levels of the DCM and ME groups did not reach significance in none of the antioxidant (TAS and FRAP) tests. Summarizing the results of this study it can be concluded that there is an increased antioxidant reactivity detected by the FRAP, but not by the TAS assay in the blood of dogs with naturally occurring cardiac disorders. The magnitude of this increase seems to be more affected rather by the severity of the cardiac insufficiency and/or by the heart rate or rhythm disorder than by the underlying heart disease itself.     

Detection of serum alpha-fetoprotein in dogs with naturally occurring malignant neoplasia

Serum alpha-fetoprotein (AFP) concentrations were determined, by use of an automated microparticle enzyme-linked immunoassay (MEIA), in 16 control dogs and 48 dogs with previously untreated, histologically confirmed, naturally occurring neoplasia (17 dogs with lymphoma and 31 dogs with nonhematopoietic malignancies, 13 dogs with carcinomas, 18 dogs with sarcomas). Mean serum AFP concentrations for untreated dogs with lymphoma, for dogs with sarcomas, and for dogs with carcinomas were not significantly different from the mean serum AFP concentration for the 16 untreated control dogs. Mean serum AFP concentration for dogs with transitional cell carcinoma (n=7) was not significantly different from the mean serum AFP concentration for the control dogs. It has been shown previously by others that a mean serum AFP concentration > 225 ng/mL is suggestive of a hepatic malignancy (e.g., hepatocellular carcinoma, lymphoma). In our study, all 48 dogs had a normal complete blood count, serum biochemical analysis, and urinalysis. Only one of the 48 dogs was found to have a serum AFP concentration > 225 ng/mL. Later evaluation of this dog confirmed hepatic involvement with lymphoma. AFP can be detected in the serum of dogs with naturally occurring tumors using the MEIA technique. A serum AFP concentration above that observed in normal dogs is not a common finding in dogs with naturally occurring neoplasia; however, we confirmed that a serum AFP concentration > 225 ng/mL, with or without evidence of a serum biochemical abnormality, may suggest primary and/or secondary hepatic involvement with a neoplastic disease and may warrant an adjustment in clinical stage and prognosis. A prospective diagnostic and therapeutic evaluation of dogs, with naturally occurring tumors having an elevated serum AFP concentration would determine the validity of this conclusion.     

Diagnosis and treatment of naturally occurring hypoadrenocorticism in 42 dogs

Hypoadrenocorticism was diagnosed in 42 dogs over a two-and-a-half-year period. The disease occurred more commonly in young to middle-aged dogs, with a female:male ratio of 2:1. Most dogs had chronic intermittent signs (eg, poor appetite, lethargy and vomiting), but more than a third were in acute adrenal crisis at the time of diagnosis. Serum biochemical testing revealed azotaemia, hyperphosphataemia, hyper-kalaemia and hyponatraemia in almost all the dogs. In all dogs, results of adrenocorticotrophic hormone (ACTH) stimulation testing revealed a low to low-normal serum baseline Cortisol concentration that failed to increase after ACTH administration. In two dogs with persistently normal serum electrolytes concentration, one had a markedly high plasma ACTH concentration diagnostic for primary hypoadrenocorticism, whereas the other had a low concentration confirming secondary hypoadrenocorticism. Fludrocortisone acetate was initially used for mineralocorticoid replacement in 33 of the 37 treated dogs withprimary hypoadrenocorticism (final median dosage, 27-0 μg/kg/day), but supplementation was changed to desoxycorticos-terone pivalate (DOCP) in four dogs because of poor response or adverse effects. Seven dogs with primary hypoadrenocorticism were treated with DOCP (final median dosage, 2-02 mg/kg/month). Prednisone, initially administered to 36 dogs, was discontinued in 11 dogs because of side effects. Of the dogs treated with fludrocortisone, the response was considered good to excellent in 26 dogs (78.8 per cent), fair in three, and poor in four. All dogs treated with DOCP responded well.