Search Results

Abstract

Objective—To evaluate markers of hemostasis and their relationship to the degree of mitral regurgitation (MR) and platelet function in Cavalier King Charles Spaniels (CKCSs) with myxomatous mitral valve disease.

Animals—76 clinically healthy CKCSs and 24 control dogs.

Procedure—All dogs underwent echocardiographic examination; various hemostatic, hematologic, and biochemical variables were evaluated in blood. The CKCSs were allocated to 1 of 3 groups on the basis of MR severity. In 8 control dogs and 8 CKCSs, plasma von Willebrand factor (vWF) multimer analysis was performed.

Results—Compared with control dogs, plasma fibrinogen concentration was higher in all CKCSs and related to left ventricular end diastolic diameter and left atrial-to-aortic root ratio among all CKCSs. The activated partial thromboplastin times and plasma Ddimer concentration were similar among the 4 groups. Plasma vWF concentration was lower in CKCSs with moderate to severe MR, compared with that of CKCSs with no MR and control dogs. There was a relationship between plasma vWF concentration and platelet function in CKCSs but not in control dogs. In 4 CKCSs with moderate to severe MR and low plasma vWF concentration, amounts of vWF high-molecular-weight multimers (HMWMs) were low.

Conclusions and Clinical Relevance—In CKCSs, MR appeared to be associated with a low plasma vWF concentration and likely a loss of vWF HMWMs (possibly through their destruction via shear stress to the blood). The importance of the changes in plasma fibrinogen concentration and the thromboembolic risk in dogs with MR remain to be investigated. (Am J Vet Res 2004;65:1644–1652)

Abstract

Objective—To compare and correlate B-mode and color Doppler ultrasonographic characteristics with histopathologic findings of benign and malignant superficial lymph nodes in dogs.

Study Population—50 superficial lymph nodes that were normal, abnormally large on physical examination, or represented regional lymph nodes draining an area of suspected primary malignancy in 30 dogs.

Procedures—Before excision, lymph nodes were evaluated via B-mode and color Doppler ultrasonography to assess size, echogenicity, presence of a hilus, acoustic transmission, and vascular flow. Formalinfixed, paraffin-embedded tissue sections of excised lymph nodes were stained with H&E and examined for the presence and extent of necrosis, fibrosis, fat, metastases, and tissue heterogeneity. To assess vascularity, the number and distribution of vessels stained by the Verhoeff van Gieson technique were recorded.

Results—In superficial lymph nodes, a varied echogenicity corresponded to tissue heterogeneity. The ultrasonographic detection of a hilus was associated with the presence of fibrous tissue, fat, or both in the hilar region. Acoustic enhancement corresponded to presence of areas of intranodal necrosis. There was significant correlation between both the distribution and the number of vessels detected via ultrasonography and that detected by histopathology. The amount of flow estimated via ultrasonography was typically higher than that estimated via histologic examination.

Conclusions and Clinical Relevance—Results indicated that histopathologic changes in canine lymph nodes have associated ultrasonographic changes and suggest that lymph node ultrasonography has an important role in the evaluation of lymph nodes in dogs in general and in dogs with neoplastic disease in particular.

Abstract

Objective—To compare and correlate B-mode and color Doppler ultrasonographic characteristics with the histologic findings of benign and malignant mammary tumors in dogs.

Study Population—49 mammary tumors in 26 dogs.

Procedures—Before excision, tumors were evaluated via B-mode and color Doppler ultrasonography to assess size, echogenicity, echopattern, acoustic transmission, invasiveness, and vascularity. Paraffinembedded microsections of the tumors were stained with H&E and examined for presence of necrosis, cysts, cartilage, bone, mineralization, invasion of surrounding tissue, and tissue heterogeneity. To assess vascularity, the number and distribution of vessels that were stained by the Verhoeff van Gieson technique were recorded.

Results—Tumor echogenicity and echopattern on ultrasonographic images correlated with tissue heterogeneity detected histologically. Acoustic enhancement was correlated with the presence of necrotic or cystic areas. Tumor invasion into surrounding tissues as determined ultrasonographically did not correlate with the histologic findings. There was a significant correlation between the number of detected vessels and distribution of flow within the tumors determined via ultrasonographic and histologic examinations.

Conclusions and Clinical Relevance—In canine mammary tumors, ultrasonographic characteristics appear to be correlated with histopathologic changes. Data suggest that ultrasonography may have an important role in the evaluation of mammary tumors in dogs, particularly in the evaluation of tissue composition and tumor vascularity.

Abstract

Objective—To investigate the hemostatic response to surgery and compare the response for ovariohysterectomy with that for ovariectomy and to evaluate the usefulness of thromboelastography on plasma samples.

Animals—42 female dogs.

Procedures—Dogs were assigned to undergo ovariohysterectomy or ovariectomy. Blood samples were collected immediately before and 1, 6, and 24 hours after surgery and stored at −80°C for subsequent analysis. Plasma samples were subjected to thromboelastography after thawing. In addition, coagulation variables were measured, including concentrations of von Willebrand factor antigen, fibrinogen, antithrombin, and protein C; activity of factor VIII; activated partial thromboplastin time; prothrombin time; and thrombin time. The fibrinolytic response was assessed via concentrations of D-dimer, plasminogen, and α-2-antiplasmin (plasmin inhibitor).

Results—Substantial hemostatic and fibrinolytic activation was evident after surgery in both groups, as characterized by significantly increased global clot strength and an overall hypercoagulable state at 4 hours after surgery in addition to decreases in von Willebrand factor antigen and factor VIII concentrations and shortened prothrombin and thrombin times. The dogs also typically had activation of the fibrinolytic system, as evidenced by increased postoperative concentrations of D-dimer, plasminogen, and plasmin inhibitor. Differences between the 2 groups could not be detected for any variables.

Conclusions and Clinical Relevance—Elective surgery with limited tissue trauma induced hemostatic activation in dogs, which led to hypercoagulability after surgery. A difference between the ovariohysterectomy and ovariectomy groups was not detected. Thromboelastography can be used on plasma samples and may be useful for evaluating patterns over time.

Abstract

Objective—To characterize acute inflammatory and hemostatic surgical stress responses following castration in cats and to evaluate whether the addition of local anesthesia to the anesthetic protocol attenuates these responses.

Animals—39 male cats.

Procedures—Cats undergoing castration were randomly assigned to 2 groups: both groups underwent surgery with general anesthesia, and 1 group additionally received a local anesthetic (lidocaine [2.0 mg/kg in total, divided intratesticularly and SC]) prior to incision. Blood samples were collected after anesthetic induction (baseline) and 1, 5, and 24 hours later. Thromboelastography and coagulation variables (activated partial thromboplastin time [aPTT] and prothrombin time [PT]) were analyzed; fibrinolysis was assessed with plasma D-dimer concentrations. The acute-phase response was evaluated via measurement of plasma fibrinogen and serum amyloid A (last time point, 28 hours) concentrations. Hematologic variables were analyzed at baseline and 1, 5, and 24 hours later.

Results—Evidence of hemostatic and inflammatory activation after surgery was detected in both groups. Maximum amplitude and G (global clot strength) were significantly increased at 24 hours, and significant, but not clinically relevant, decreases were detected in aPTT at 5 and 24 hours and in PT at 24 hours, compared with baseline values. Serum amyloid A concentrations were significantly higher at 24 and 28 hours than at baseline, and plasma fibrinogen concentration was significantly increased at 24 hours; WBC and RBC counts and Hct were significantly increased at multiple time points. No differences between groups were detected for any variables.

Conclusions and Clinical Relevance—Castration appeared to induce hypercoagulability and an acute-phase inflammatory response in cats. Local anesthesia with lidocaine did not attenuate this response.

Abstract

Objective—To develop an antibody-based flow cytometric assay to detect coated platelets in dogs and to characterize the interaction of recombinant human coagulation factor VIIa with activated platelets from dogs with hemophilia A.

Sample—Platelets from 4 dogs with hemophilia A, 4 dogs with hemophilia B, 4 dogs with von Willebrand disease, and 6 hemostatically normal dogs.

Procedures—Freshly isolated platelets were activated with thrombin, convulxin, or a thrombin-convulxin combination. Resulting platelet phenotypes were resolved on the basis of P-selectin and fibrinogen expression, and binding of recombinant human coagulation factor VIIa to these distinct platelet subpopulations was measured by use of a flow cytometric assay.

Results—Coated platelets were identified on the basis of expression of α-granule fibrinogen and were generated in response to stimulation with the thrombin-convulxin combination but not to stimulation with either agonist alone. Approximately 70% of the platelets from dogs with hemophilia A, hemophilia B, and von Willebrand disease and from the control dogs had the coated platelet phenotype. Recombinant human coagulation factor VIIa bound preferentially to coated platelets with a mean ± SD binding equilibrium constant of 2.6 ± 0.5μM.

Conclusions and Clinical Relevance—Formation of coated platelets in dogs was similar to that in humans. Recombinant human coagulation factor VIIa bound preferentially to coated platelets from dogs.

Impact for Human Medicine—A similar mechanism of action for recombinant human coagulation factor VIIa may exist in dogs and humans. The potential for use of dogs in the study of bleeding disorders in humans was strengthened.

Abstract

OBJECTIVE To identify minimally invasive biomarkers to help differentiate dogs with gastric carcinoma from those with chronic gastritis.

DESIGN Prospective study.

ANIMALS 15 dogs with gastric carcinoma, 29 dogs with chronic gastritis, and 7 healthy dogs.

PROCEDURES Dogs with clinical signs of upper gastrointestinal tract disease for > 14 days that underwent gastroscopy or necropsy for collection of gastric biopsy specimens for histologic evaluation were prospectively enrolled. Gastric carcinoma and chronic gastritis were diagnosed on the basis of histologic findings. Additionally, gastric biopsy specimens were collected endoscopically from 7 healthy (control) dogs while they were anesthetized for a routine neutering procedure. Prior to being anesthetized for gastroscopy or euthanized, all dogs underwent a physical examination, and a blood sample was collected for quantification of select serum biomarker concentrations. Histologic findings, body condition score (BCS), and serum biomarker concentrations were compared among the 3 groups.

RESULTS Dogs with gastric carcinoma were significantly older and had a significantly lower BCS, lower serum folate concentration, and greater serum C-reactive protein (CRP) concentration, compared with dogs with chronic gastritis and control dogs.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that age > 8 years, BCS < 4, serum CRP concentration > 25 mg/L, and an abnormally low serum folate concentration might be useful noninvasive biomarkers for identification of dogs with gastric carcinoma. For underweight older dogs with signs of upper gastrointestinal tract disease and high serum CRP and low serum folate concentrations, gastric biopsy specimens should be obtained and evaluated so that a prompt definitive diagnosis can be made and appropriate treatment initiated.

Abstract

Objective—To compare results of body condition scoring by use of a 9-point scale with body composition determined by dual-energy x-ray absorptiometry (DEXA) in indoor-confined neutered domestic shorthair (DSH) pet cats.

Animals—72 indoor-confined, adult neutered DSH pet cats (38 females and 34 males).

Procedures—All cats underwent a physical examination including assessment of body weight (BW), body condition score (BCS; 1 = emaciated, 5 = ideal, and 9 = grossly obese), and girth. Urinalysis, CBC, and serum biochemical analysis were also performed. After the cats were confirmed healthy, they were anesthetized for body composition measurement via DEXA. Lean body mass, fat mass, and percentage body fat (%BF) were then evaluated.

Results—The correlation between %BF and BCS (r = 0.87) was superior to the correlations between %BFand BW (r = 0.74) and between %BF and girth (r = 0.78). Values for %BF differed significantly between all pairs of BCSs except BCSs 8 and 9. Within a BCS, the %BF was similar for male and female cats. The mean %BF for cats with a BCS of 5 was 32, which exceeded the upper reference limit of %BF generally considered ideal (30).

Conclusions and Clinical Relevance—The 9-point BCS scale appears useful for assessing %BF in DSH pet cats. Nevertheless, study findings could indicate a need for redefining the ideal BCS for inactive neutered cats to include a BCS of 4.

Abstract

OBJECTIVE To investigate serum and plasma serotonin concentrations, percentage of serotonin-positive platelets, level of surface-bound platelet serotonin expression (mean fluorescence intensity [MFI]), and platelet activation (CD62 expression) in platelet-rich plasma from Cavalier King Charles Spaniels with myxomatous mitral valve disease (MMVD).

ANIMALS Healthy dogs (n = 15) and dogs with mild MMVD (18), moderate-severe MMVD (19), or severe MMVD with congestive heart failure (CHF; 10).

PROCEDURES Blood samples were collected from each dog. Serum and plasma serotonin concentrations were measured with an ELISA, and surface-bound platelet serotonin expression and platelet activation were determined by flow cytometry.

RESULTS Dogs with mild MMVD had higher median serum (746 ng/mL) and plasma (33.3 ng/mL) serotonin concentrations, compared with MMVD-affected dogs with CHF (388 ng/mL and 9.9 ng/mL, respectively), but no other group differences were found. Among disease groups, no differences in surface-bound serotonin expression or platelet activation were found. Thrombocytopenic dogs had lower serum serotonin concentration (482 ng/mL) than nonthrombocytopenic dogs (731 ng/mL). In 26 dogs, a flow cytometry scatterplot subpopulation (FSSP) of platelets was identified; dogs with an FSSP had a higher percentage of serotonin-positive platelets (11.0%), higher level of surface-bound serotonin expression (MFI, 32,068), and higher platelet activation (MFI, 2,363) than did dogs without an FSSP (5.7%, 1,230, and 1,165, respectively). An FSSP was present in 93.8% of thrombocytopenic dogs and in 29.5% of nonthrombocytopenic dogs.

CONCLUSIONS AND CLINICAL RELEVANCE A substantive influence of circulating serotonin on MMVD stages prior to CHF development in Cavalier King Charles Spaniels was not supported by the study findings. An FSSP of highly activated platelets with pronounced serotonin binding was strongly associated with thrombocytopenia but not MMVD.