Hemostatic biomarkers in dogs with chronic congestive heart failure

BACKGROUND: Chronic congestive heart failure (CHF) in humans is associated with abnormal hemostasis, and abnormalities in hemostatic biomarkers carry a poor prognosis. Alterations in hemostatic pathways can be involved in the pathogenesis of CHF in dogs, and microthrombosis in the myocardium could contribute to increased mortality. HYPOTHESIS: That plasma concentration or activity of hemostatic biomarkers is altered in dogs with CHF and that these factors predict mortality. ANIMALS: Thirty-four dogs with CHF caused by either dilated cardiomyopathy (DCM, n=14) or degenerative valvular disease (CDVD, n=20) compared with 23 healthy age-matched control dogs were included in this study. Dogs with CHF were recruited from 2 referral cardiology clinics, and control dogs were owned by friends or colleagues of the investigators. METHODS: Clinical examination and echocardiography were performed in all dogs. Plasma fibrinogen and D-dimer concentrations, antithrombin and protein C activity, and thrombin-antithrombin complex (TAT) were measured in all dogs. RESULTS: Dogs with CHF had significantly higher fibrinogen (P = .04), D-dimer (P = .002), and TAT concentration (P < .0001), lower antithrombin (P < .0001) and protein C activity (P < .001) compared with control dogs. None of the hemostatic biomarkers were associated with risk of death. CONCLUSIONS AND CLINICAL IMPORTANCE: There is evidence of a procoagulant state in dogs with CHF. The lack of predictive value for survival might be due to the small number of dogs examined. Further studies are necessary to investigate the presence and importance of microthrombosis in dogs with CHF.     

Detection of activated platelets in dogs with primary immune-mediated hemolytic anemia

Thromboembolism is a major cause of morbidity and mortality in dogs with immune-mediated hemolytic anemia (IMHA). To the authors' knowledge, the role of platelets in thromboembolic events associated with IMHA has not been extensively investigated. In the study reported here, we evaluated cell membrane expression of P-selectin with flow cytometry to determine whether platelets circulate in an activated state in association with primary IMHA. Median P-selectin expression for 20 dogs with primary IMHA was 8.1-fold greater, compared with values for 20 healthy dogs. Fifteen of 20 dogs (75%) with IMHA had P-selectin median fluorescence intensity (MFI) values that exceeded the reference interval for healthy dogs. Additionally, P-selectin MFI after activation of platelets with phorbol myristate acetate was 2.1-fold greater for dogs with IMHA than for healthy control dogs. Despite treatment of all dogs with immunosuppressive therapy and 18 dogs with subcutaneously administered low-dose unfractionated heparin, 7 dogs developed clinical signs consistent with thromboembolism. These data provide support for the hypothesis that platelets circulate in an activated state in many dogs with IMHA.     

The Gastrointestinal Microbiome: A Review

The gastrointestinal microbiome is a diverse consortium of bacteria, archaea, fungi, protozoa, and viruses that inhabit the gut of all mammals. Studies in humans and other mammals have implicated the microbiome in a range of physiologic processes that are vital to host health including energy homeostasis, metabolism, gut epithelial health, immunologic activity, and neurobehavioral development. The microbial genome confers metabolic capabilities exceeding those of the host organism alone, making the gut microbiome an active participant in host physiology. Recent advances in DNA sequencing technology and computational biology have revolutionized the field of microbiomics, permitting mechanistic evaluation of the relationships between an animal and its microbial symbionts. Changes in the gastrointestinal microbiome are associated with diseases in humans and animals including inflammatory bowel disease, asthma, obesity, metabolic syndrome, cardiovascular disease, immune‐mediated conditions, and neurodevelopmental conditions such as autism spectrum disorder. While there remains a paucity of data regarding the intestinal microbiome in small animals, recent studies have helped to characterize its role in host animal health and associated disease states. This review is intended to familiarize small animal veterinarians with recent advances in the field of microbiomics and to prime them for a future in which diagnostic tests and therapies will incorporate these developments into clinical practice.     

Evaluation of a modified thrombelastography assay initiated with recombinant human tissue factor in clinically healthy horses

Background: Thrombelastography (TEG) is used to evaluate the viscoelastic properties of blood during clotting and provides a global assessment of hemostasis and clot lysis. TEG analysis initiated with recombinant human tissue factor (TF) has not been evaluated in clinically healthy horses. Objectives: The purpose of this study was to determine whether TEG results are affected by the time elapsed between sampling and analysis (storage time) of equine blood samples and to establish a preliminary equine reference interval for a modified TEG assay, using recombinant human TF to initiate coagulation. Methods: Citrated blood samples were obtained from 20 clinically healthy adult horses. Thirteen samples were stored for 30, 60, and 120 minutes at room temperature before TEG analysis. Coagulation was initiated by adding 20 μL of CaCl₂ to 330 μL of blood and 10 μL of diluted recombinant TF for a final dilution of 1:3600. Reaction (R) and clotting (K) times, angle (α), and maximum amplitude (MA) were compared between time points. A preliminary reference interval (minimum–maximum values) was determined using data from all 20 horses after 30 minutes of sample storage. Results: There was a significant effect of storage time on R, K, and α but not MA. Reference intervals were: R, 3.65–6.4 minutes; K, 1.8–5.45 minutes; α, 33.4–66.2°; MA, 41.2–64.1 mm; lysis at 30 minutes post‐MA (LY30), <2.75%; and lysis at 60 minutes post‐MA (LY60), 1.55–9.5%. Conclusions: TEG can be performed on equine citrated blood samples using recombinant human TF to activate clot formation. TEG parameters were significantly affected by storage time, suggesting an incomplete inhibition of coagulation in citrated blood.     

Plasma Antithrombin Activity as a Diagnostic and Prognostic Indicator in Dogs: A Retrospective Study of 149 Dogs

Background: Antithrombin (AT) is the major inhibitor of coagulation. In people, hypoantithrombinemia is associated with hypercoagulability, thrombosis, and poor prognosis. Veterinary studies, however, have not demonstrated similar prognostic significance. Thus, AT activity (ATA) in dogs currently is interpreted based on human medicine guidelines. Hypothesis: ATA can serve as a prognostic marker in dogs, as has been shown in people. Objectives: (1) To describe the clinical and clinicopathologic findings, diagnoses, and outcome of dogs with decreased versus normal ATA, (2) to identify diseases and mechanisms associated with hypoantithrombinemia, and (3) to assess ATA as a prognostic indicator. Animals and Methods: Retrospective study of 149 dogs with ATA measurement during their disease course. Results: Hypoantithrombinemic dogs had a higher proportion of leukocytosis, hemostatic abnormalities, hypoalbuminemia, and hyperbilirubinemia versus dogs with normal ATA. Hypoantithrombinemia commonly was present in immune‐mediated hemolytic anemia (IMHA), pancreatitis, hepatopathy, and neoplasia. It was associated with higher risk of mortality in the entire study population and for specific diseases (eg, IMHA, neoplasia). The odds ratio for mortality significantly and progressively increased when ATA was <60 and <30% (9.9, 14.7, respectively). A receiver operating characteristics analysis of ATA as a predictor of mortality showed an area under the curve of 0.7, and an optimal cutoff point of 60% yielded sensitivity and specificity of 58 and 85%, respectively. Conclusions and Clinical Importance: In dogs, ATA <60% indicates increased mortality risk, similarly to human patients, but ATA has limited value as a single discriminating factor in the outcome.     

Antithrombotic Effect of Enoxaparin in Clinically Healthy Cats: A Venous Stasis Model

Background: Systemic arterial thromboembolic events are a serious complication of cardiac disease in cats.
Objectives: To determine if enoxaparin induces an antithrombotic effect in cats at a dosage of 1 mg/kg SC q12h and if this antithrombotic effect is predicted by anti-Xa activity.
Animals: Fourteen clinically healthy cats were divided into 3 groups: control (4 cats), treated and assessed at 4 hours (5 cats), and treated and assessed at 12 hours (5 cats).
Methods: A venous stasis model was used and the extent of thrombus formation estimated by measuring thrombus weight and accretion of ¹²⁵I-fibrinogen. Plasma anti-Xa activity was measured in treated cats.
Results: There was a significant reduction in thrombus formation in the 4 h group compared with control (median weight, 0.000 versus 0.565 mg/mm, P < .01; median %¹²⁵I-fibrinogen accretion, 0.0 versus 42.0%, P < .01). There was a reduction in thrombus formation in the 12 h group (median weight, 0.006 mg/mm, P = .09; median %¹²⁵I-fibrinogen accretion, 3.83%, P = .09) but this reduction was not significant. The median percent thrombus inhibition for treated cats was 100.0% at 4 hours and 91.4% at 12 hours. Plasma anti-Xa activity was not significantly correlated with thrombus formation.
Conclusions and Clinical Importance: This pilot study demonstrates that enoxaparin, when administered at a dosage of 1 mg/kg SC q12h, produces an antithrombotic effect in a venous statsis model in clinically healthy cats. Furthermore, this study demonstrates that anti-Xa activity is a poor predictor of enoxaparin's antithrombotic effect.     

Electrosurgery: A Review

This article presents a review of hemostasis and electrosurgery. The principles of electrosurgery, including the effect on tissue, vessels, and wound healing, are presented, as are the advantages and disadvantages of its use.     

草地生态系统土壤氮转化过程研究进展

针对草地生态系统土壤氮的转化过程中氮的矿化和固定、硝化和反硝化的研究进展进行综述,总结了不同草地利用方式、主要环境因素变化对氮转化过程的影响,并对草地生态系统土壤氮转化研究的前沿进行了展望。     

A comparison of the methods for determination of the rennet coagulation properties of milk

Abstract

The objective of the present study was to compare two methods for measuring the rennet coagulation properties of milk: the Formagraph, and the Optigraph. The parameters used to describe rennet coagulation of 81 milk samples were rennet coagulation time (RCT, Formagraph, and R, Optigraph) and curd firmness 30 min after the addition of rennet (E₃₀, Formagraph, and A₃₀, Optigraph).

New Optigraph system recipes were found: R slope?=?1.784 and R offset?=???2.303. Using the above Optigraph system recipes, no statistically significant differences were found in rennet coagulation time measurements in either of the studied methods. Regarding curd firmness, the best approximation to describe the relationship between the methods was polynomial: E₃₀=???0.0357*A₃₀ ²+2.8795*A₃₀ ?5.2991 (R ² =0.925). Such strong correlations indicate that the two techniques for detecting milk coagulation properties are comparable and that the data obtained by these methods allow for data interpretation in studies using either method.     

Bovine Campylobacteriosis: A Review

Campylobacteriosis (vibriosis) is a venereal disease of cattle caused by the organism Campylobacter fetus subspecies fetus previously known as Vibrio fetus subspecies venerealis. Characteristically the disease causes infertility in the female with an increased number of services necessary for conception. Abortions late in gestation are also occasionally seen. Most cases or outbreaks occur after the recent introduction of an infected bull or cow into a susceptible breeding herd. Often the disease remains undetected until late fall when the livestock owner recognizes that he has a number of females exhibiting estrus. A tentative diagnosis can be made by a study of the herd history and can often be confirmed by laboratory means.

In recent years many advances have been made towards establishing an understanding of the immune response that occurs with infection and systemic immunization. In this review, recommendations are made regarding the appropriate time to immunize the breeding herd against campylobacteriosis.

     

Halothane Hepatitis: A Review

The literature relating to hepatic disease following halothane anesthesia is reviewed. Evidence in support of a direct hepatotoxic effect by halothane is lacking, but the rare occurrence of a hypersensitivity reaction after repeated halothane exposure is well documented. This information is of significance for veterinarians repeatedly exposed to trace amounts of halothane.     

A prospective study of clopidogrel therapy in dogs with primary immune-mediated hemolytic anemia

Background: A major cause of death in dogs with primary immune‐mediated hemolytic anemia (pIMHA) is thrombotic disease. Ultralow‐dose aspirin (ULDA) is commonly used to prevent thrombosis in dogs with pIMHA; however, the efficacy of antiplatelet agents in dogs with pIMHA is unknown. Hypothesis: The use of clopidogrel (CL), alone or in combination with ULDA, would improve survival to discharge and at 90 days without important adverse effects compared with ULDA alone in dogs with pIMHA treated with standard immunosuppressive therapy. Animals: Twenty‐four client‐owned dogs with pIMHA. Methods: Prospective, positive‐controlled, unmasked clinical trial with dogs randomized in 3 treatment groups to receive PO ULDA or CL or both. Results: There was no identifiable adverse reaction, evidence of hemorrhage, or increase in transfusion requirements associated with CL therapy, either alone or combined with ULDA, compared with ULDA alone. There was no significant difference between treatment groups with respect to survival to discharge and at 90 days. Conclusions and Clinical Importance: This study suggests that CL therapy, alone or in combination with ULDA, was safe and had similar short‐term survival compared with ULDA alone in a small group of dogs with pIMHA able to tolerate oral medications and treated with standard immunosuppressive treatment.     

Deer Fibroma: A Review

Fibromas are frequent cutaneous neoplasms of young deer of many species, characterized by proliferation of both epithelial and dermal cells. Virus particles, similar to those found in fibrous skin tumors of several wild and domestic species, have been identified in some species by electron microscopy. Attempted transmission of fibromas has not been uniformly successful using filtered preparations.     

The Immunotherapy of Canine Osteosarcoma: A Historical and Systematic Review

Osteosarcoma is a malignant mesenchymal neoplasm that accounts for the majority of primary bone tumors in dogs and shares biological and clinical similarities with osteosarcoma in humans. Despite dose intensification with conventional cytotoxic therapies, survival times for dogs and humans diagnosed with high‐grade osteosarcoma have not changed in the past 20 years, with the principal cause of mortality being the development of pulmonary metastases. Given the therapeutic plateau reached for delaying metastatic progression with cytotoxic agents, exploration of alterative adjuvant therapies for improving management of osteosarcoma micrometastases is clinically justified. Evidence suggests that osteosarcoma is an immunogenic tumor, and development of immunotherapies for the treatment of microscopic lung metastases might improve long‐term outcomes. In this review, the history and foundational knowledge of immune interactions to canine osteosarcoma are highlighted. In parallel, immunotherapeutic strategies that have been explored for the treatment of canine osteosarcoma are summarized. With a greater understanding and awareness for how the immune system might be redirected toward combating osteosarcoma metastases, the rational development of diverse immune strategies for managing osteosarcoma holds substantial promise for transforming the therapeutic landscape and improving disease management in both dogs and human beings.     

Canine specific ELISA for coagulation factor VII

Canine coagulation factor VII (FVII) deficiency can be hereditary or acquired and may cause life threatening bleeding episodes if untreated. FVII procoagulant activity can be measured by FVII activity (FVII:C), but assays for measurement of canine specific FVII antigen (FVII:Ag) have not been available to date. In this study, a canine specific ELISA for measurement of FVII:Ag in plasma was developed and validated. The FVII:Ag ELISA correctly diagnosed homozygous and heterozygous hereditary FVII deficiency. Together with activity based assays, such as FVII:C, the FVII:Ag ELISA should be valuable in the diagnosis of hereditary canine FVII deficiency.