Sara Zaldívar-López

Clinical pathology of Greyhounds and other sighthounds

Owing to the development of Greyhounds as racing sighthounds, these dogs have acquired unique physiologic adaptations that distinguish them from other breeds. Reference intervals for many analytes in retired racing Greyhounds (RRGs) differ from those of other breeds; most of the hematologic differences have also been described in other sighthounds. In this review, we provide a survey of the literature on clinical pathology of Greyhounds and other sighthounds and results of laboratory testing, including analysis of CBCs, biochemical profiles, coagulation tests, and blood gases, in RRGs at The Ohio State University. Major clinicopathologic differences in this breed include higher RBC mass, creatinine concentration, glomerular filtration rate, activities of hepatic enzymes, and concentration of cardiac troponin, as well as lower WBC, neutrophil, and platelet counts, thromboelastographic values, and concentrations of serum haptoglobin, total globulins, and T4.

Epsilon aminocaproic acid for the prevention of delayed postoperative bleeding in retired racing greyhounds undergoing gonadectomy.

OBJECTIVE To evaluate the effects of epsilon aminocaproic acid (EACA) on the prevalence of postoperative bleeding in retired racing Greyhounds (RRG), and to assess its effects on selected thrombelastography (TEG) and fibrinolysis variables. STUDY DESIGN Double-blinded, prospective, randomized study. METHODS 100 RRG had elective ovariohysterectomy or orchiectomy and were administered EACA or placebo for 3 days after surgery. TEG variables were analyzed preoperatively and 24, 48, and 72 hours after surgery. RESULTS Thirty percent (15/50) of RRG in the placebo group had delayed postoperative bleeding starting 36-48 hours after surgery compared with 10% (5/50) in the EACA group (P = .012). On the TEG variables, the slopes for R and K time were significantly different between treatment groups (P <.05); the R and K time decreased over time in the EACA group after surgery whereas they increased in the placebo group. The angle, maximal amplitude (MA), and G slopes were also significantly different between treatment groups (P = .001, .001, and .006, respectively). The angle, MA, and G increased postoperatively over time in the EACA group and decreased in the placebo group. All these changes are supportive of hypercoagulability associated with EACA administration. CONCLUSION Postoperative administration of EACA significantly decreased the prevalence of postoperative bleeding in RRG undergoing surgery by increasing the clot strength.

Retrospective evaluation of the effectiveness of epsilon aminocaproic acid for the prevention of postamputation bleeding in retired racing Greyhounds with appendicular bone tumors: 46 cases (2003–2008)

OBJECTIVES To determine the frequency of delayed postoperative bleeding in retired racing Greyhounds with appendicular bone tumors undergoing limb amputations. To identify if administration of epsilon-aminocaproic acid (EACA) was effective on the prevention of postoperative bleeding. DESIGN Retrospective study from December 2003 to December 2008. SETTING Veterinary university teaching hospital. ANIMALS Forty-six retired racing Greyhounds (RRGs) diagnosed with primary appendicular bone tumors that underwent limb amputation were included in the study. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Thirteen of 46 RRGs (28%) included in the study had delayed postoperative bleeding starting 48-72 h after surgery. Bleeding episodes included cutaneous, subcutaneous, and external bleeding that extended from the area of the surgical site that became widespread within hours, and that required administration of blood components. A paired t-test suggests that there was a significant decrease in PCV postoperatively for both dogs that bled and dogs that did not bleed (P < 0.0001). Forty of 46 RRGs (86%) received either fresh frozen plasma (FFP) or EACA or both, for the prevention of postoperative bleeding. A logistic regression model determined that dogs that did not receive EACA were 5.7 times more likely to bleed than dogs that did receive EACA, when controlling for whether or not they received FFP (95% CI: 1.02-32.15, P = 0.047). CONCLUSION This retrospective study suggests that preemptive postoperative administration of EACA appears to be efficacious in decreasing the frequency of bleeding in RRGs undergoing limb amputation; however, a prospective study is warranted to corroborate its effectiveness.

Blood gas analysis and cooximetry in retired racing Greyhounds

OBJECTIVE The purposes of this study were to evaluate the oxygen affinity of hemoglobin (Hb) in healthy retired racing Greyhounds via cooximetry, and to establish reference intervals for blood gases and cooximetry in this breed. DESIGN Prospective clinical study. SETTING University Teaching Hospital. ANIMALS Fifty-seven Greyhounds and 30 non-Greyhound dogs. INTERVENTIONS Venous blood samples were collected from the jugular vein and placed into heparinized tubes. The samples were analyzed within 30 minutes of collection using a blood gas analyzer equipped with a cooximeter. MEASUREMENTS AND MAIN RESULTS Greyhounds had significantly higher pH, PO(2) , oxygen saturation, oxyhemoglobin, total Hb, oxygen content, and oxygen capacity and significantly lower deoxyhemoglobin and P(50) when compared with non-Greyhound dogs. CONCLUSION These findings support the fact that this breed is able to carry a higher concentration of total oxygen in the blood. As reported previously, this breed also has lower P(50) and, therefore, high oxygen affinity. In light of recent findings suggesting that in certain tissues a high affinity for oxygen is beneficial, this adaptation may be of benefit during strenuous exercise.

Markers of iron metabolism in retired racing Greyhounds with and without osteosarcoma

BACKGROUND Greyhounds have well-described clinicopathologic idiosyncrasies, including a high prevalence of osteosarcoma (OSA). Hematocrit, HGB, and HGB oxygen affinity are higher than in other dogs, while haptoglobin concentration is lower, so we hypothesized that Greyhounds have a different iron metabolism. To our knowledge, there are no reports on serum iron profiles in Greyhounds. OBJECTIVES To elucidate iron metabolism in Greyhounds, we wanted to compare serum iron concentration, total iron-binding capacity (TIBC), and percent transferrin saturation (%SAT) in healthy retired racing Greyhounds (RRGs) with OSA (RRGs - OSA), and also with non-Greyhounds (NGs), without and with OSA (NGs - OSA). METHODS Serum iron concentration and unsaturated iron-binding capacity (UIBC) were measured by standard methods, and TIBC and %SAT were calculated in RRGs (n = 25), RRGs - OSA (n = 28), NGs (n = 30), and NGs - OSA (n = 32). RESULTS TIBC was lower in RRGs than in NGs (P < .0001), and in RRGs - OSA than in NGs - OSA (P < .0001). NGs - OSA had lower TIBC than healthy NGs (P = .003). Percent SAT was higher in RRGs than in NGs (P < .0001) and in RRGs - OSA (P = .008), and %SAT was also lower in NGs than in NGs - OSA (P = .004). Percent SAT was also higher in RRGs - OSA than in NGs - OSA (P = .001). Both RRGs - OSA (P = .02) and NGs - OSA (P < .0001) had lower serum iron concentrations than their healthy counterparts. CONCLUSION Lower TIBC and higher %SAT may constitute another Greyhound idiosyncrasy compared with other dogs. In this study, all dogs with OSA had higher serum iron concentrations and %SAT than healthy dogs.

Comparative genomics of canine hemoglobin genes reveals primacy of beta subunit delta in adult carnivores

BackgroundThe main function of hemoglobin (Hb) is to transport oxygen in the circulation. It is among the most highly studied proteins due to its roles in physiology and disease, and most of our understanding derives from comparative research. There is great diversity in Hb gene evolution in placental mammals, mostly in the repertoire and regulation of the β-globin subunits. Dogs are an ideal model in which to study Hb genes because: 1) they are members of Laurasiatheria, our closest relatives outside of Euarchontoglires (including primates, rodents and rabbits), 2) dog breeds are isolated populations with their own Hb-associated genetics and diseases, and 3) their high level of health care allows for development of biomedical investigation and translation.ResultsWe established that dogs have a complement of five α and five β-globin genes, all of which can be detected as spliced mRNA in adults. Strikingly, HBD, the allegedly-unnecessary adult β-globin protein in humans, is the primary adult β-globin in dogs and other carnivores; moreover, dogs have two active copies of the HBD gene. In contrast, the dominant adult β-globin of humans, HBB, has high sequence divergence and is expressed at markedly lower levels in dogs. We also showed that canine HBD and HBB genes are complex chimeras that resulted from multiple gene conversion events between them. Lastly, we showed that the strongest signal of evolutionary selection in a high-altitude breed, the Bernese Mountain Dog, lies in a haplotype block that spans the β-globin locus.ConclusionsWe report the first molecular genetic characterization of Hb genes in dogs. We found important distinctions between adult β-globin expression in carnivores compared to other members of Laurasiatheria. Our findings are also likely to raise new questions about the significance of human HBD. The comparative genomics of dog hemoglobin genes sets the stage for diverse research and translation.

Budd-Chiari Like Syndrome Associated with a Primary Pulmonary Adenocarcinoma in a Dog

A 10-year-old female crossbred dog of 6 kg bodyweight was presented with signs of marked abdominal distention. The abdominal skin vasculature appeared prominent. After an exhaustive physical examination, laboratory analysis (table 1) and imaging studies, the case was diagnosticated as Budd-Chiari like syndrome due to lung adenocarcinoma. Abdominal ultrasonography revealed a neoplasia of 4 cm in diameter with irregular borders located in right accessory lung in contact with the caudal vena cava and surface thorax of the diaphragm. Immediately after sonographic diagnosis, the canine was admitted to intensive care and hemodynamically stabilized and submitted to surgery after 24 hrs. Then we made a exploratory thoracotomy with intention of achieve a lung lobectomy. After surgery chemotherapy with doxorrubicin 30 mg/m2 was administered. The objective of our study was to describe the image and pathological data findings in a dog with Budd-Chiari like syndrome; including sonographic findings, treatment and its response, in a syndrome that rarely affect small animals. Although no data are available on incidence of this disease in veterinary medicine, there is no doubt that this is a very serious illness despite its rare appearance. To our knowledge, this is one of the few cases where BCLS is reported associated to lung adenocarcinoma in veterinary medicine.