Assessment of hemostasis in hyperthyroid and euthyroid cats using two viscoelastic assays and platelet aggregometry

BACKGROUND

Hyperthyroidism in humans is associated with a hypercoagulable state and an increased risk of thromboembolism.

OBJECTIVE

To evaluate hemostatic variables in hyperthyroid and euthyroid cats with the hypothesis that hyperthyroid cats will have evidence of altered hemostasis consistent with a potential hypercoagulable state.

ANIMALS

Client-owned hyperthyroid (n = 16) and euthyroid (n = 15) cats over 8 years of age.

METHODS

Prospective observational study. Hyperthyroid and euthyroid cats were enrolled. Rotational thromboelastometry (ROTEM), whole-blood platelet impedance aggregometry (WBPIA) and a point-of-care viscoelastic coagulation monitor (VCM-Vet) were performed immediately after minimally traumatic venipuncture under sedation.

RESULTS

Hyperthyroid cats had significantly higher values for variables as assessed by VCM-Vet: A10 (34 [17-47] vs 25 [17-38], P = .003); A20 (39.5 [23-55] vs 31 [21-45], P = .003); and MCF (41 [24-58] vs 35 [22-49], P = .03). Hyperthyroid cats had significantly different values versus the euthyroid cohort as assessed by different ROTEM channels: increased A10, INTEM (61.5 [39-75] vs 54 [23-66], P = .007) and FIBTEM (18 [10-35] vs 13 [2-27], P = .01); increased A20, INTEM (68 [45-78] vs 61 [30-70], P = .006) and FIBTEM (17 [10-34] vs 11 [2-25], P = .002); increased MCF, EXTEM (72 [65-81] vs 69 [34-78], P = .04), INTEM (70 [45-85] vs 62 [35-71], P = .01) and FIBTEM (18 [13-37] vs 14 [3-27], P = .02); increased alpha angle, EXTEM (80 [68-85] vs 76 [41-84], P = .01); shortened CT, EXTEM (52.5 [29-73] vs 60 [52-92], P = .003) and FIBTEM (52.5 [16-75] vs 65 [53-165], P = .001); and decreased ML, FIBTEM (20 [1-36] vs 33 [19-59], P <.001). No significant differences were found with WBPIA.

CONCLUSIONS AND CLINICAL IMPORTANCE

The hyperthyroid cats in this study had evidence of altered hemostasis as assessed by 2 viscoelastic methodologies, and characterized by increased clot amplitude, firmness, and faster coagulation times vs euthyroid controls.

Computed tomographic and bronchoscopic diagnosis of Oslerus osleri infection in a dog

A 16-month-old Sarplaninac Shepherd cross dog presented for a 1-month history of a productive cough that was unresponsive to an empirical 10-day course of cephalexin. Thoracic computed tomography (CT) showed multifocal, well-defined, smoothly marginated, soft tissue attenuating, minimally contrast enhancing nodular airway mural thickenings protruding into the airway lumen in the caudal trachea and principal bronchi. These nodules were also visualized on bronchoscopy, and cytology revealed parasitic larvae consistent with Oslerus osleri. The dog was treated with oral fenbendazole for 26 days. Clinical signs resolved within 3 weeks of treatment initiation and had not relapsed at 7-month follow-up.

The effect of per os vs subcutaneous 123 iodine administration on percentage thyroidal radioactive iodine uptake in normal cats

Background

Historical and recent literature disagree on whether a higher PO ¹³¹I dosage, compared to IV or SC routes, is required for successful resolution of spontaneous hyperthyroidism in cats, necessitating investigation into the effect of PO and injectable radioactive iodine administration on % thyroidal radioactive iodine uptake (RAIU).

Hypothesis/Objectives

To investigate the effect of PO and SC routes of ¹²³I administration on paired % thyroidal RAIU in euthyroid cats. Specifically, a 1.5‐fold difference (50% relative change) was hypothesized, which in absolute terms can be expressed as a 3.25% increase in the mean %RAIU of 7.04% after PO ¹²³I administration to 10.56% after SC dosing.

Animals

Seven healthy euthyroid teaching‐research colony cats.

Methods

A randomized, radiologist‐blinded crossover study comparing %RAIU after PO and SC ¹²³I administration.

Results

Percentage thyroidal RAIU values (mean ± SD; 95% confidence interval) after PO (4.81% ± 1.63%; 3.30%‐6.23%) and SC (5.26% ± 2.43%; 3.01%‐7.51%) ¹²³I administration were associated with a median within‐pair absolute difference of 0.2% (range: min, 0.1%‐max, 4.9%). Statistical significance was not achieved (P  =  .45). Six of 7 cats had a within‐pair absolute difference of 0.1% to 0.9% (relative change of 4%‐20%), but a single outlier cat had a within‐pair absolute difference of 4.9% (relative change of 108%).

Conclusions and Clinical Importance

This study did not detect an effect of ¹²³I administration route on paired % thyroidal RAIU in euthyroid cats. However, a type 2 statistical error due to small sample size is possible.

Pharmacokinetic and Safety Evaluation of Various Oral Doses of a Novel 1:20 THC:CBD Cannabis Herbal Extract in Dogs

Objective: To determine the pharmacokinetics (PK) and safety of various oral doses of a Cannabis herbal extract (CHE) containing a 1:20 ratio of Δ9-tetrahydrocannabinol (THC):cannabidiol (CBD) in 13 healthy Beagle-cross dogs.

Methods: Single-dose PK was assessed after oral administration of CHE at low, medium, or high doses [2, 5, or 10 mg CBD and 0.1, 0.25, or 0.5 mg THC per kg of body weight (bw), respectively; n = 6 per group]. Dogs were monitored for adverse events for up to 48 h post-dose. Evaluations of neurological signs, clinical laboratory abnormalities, and other adverse events were performed in two separate study phases: a multiple-dose phase with 12 dogs receiving five medium doses (5 mg CBD/kg bw) at 12 h intervals, and a single low-dose (2 mg CBD/kg bw), randomized, blinded, negative controlled study with 13 dogs.

Results: Cannabinoids CBD, THC, CBC, and metabolites 6-OH-CBD, 7-OH-CBD, 11-OH-THC, and THC-COOH were quantified in plasma. CBD and THC were rapidly absorbed (mean T_max of 1.9–2.3 h) and initially depleted rapidly (mean CBD T_1/2β of 2.3–2.6 h). A prolonged elimination phase (mean CBD T_1/2λ of 13.3–24.4 h) was observed. CBD and THC concentrations increased in a dose-dependent (non-linear) manner, with disproportionally greater cannabinoid exposure relative to the dose increase. Neurological signs (hyperesthesia or proprioceptive deficits) were noted in five of six dogs in the high-dose group, but only occasionally or rarely in the medium- and low-dose groups, respectively. Presence and severity of clinical signs correlated with plasma cannabinoid concentrations. Dogs appeared to develop a tolerance to cannabinoid effects after multiple CHE doses, with fewer neurological signs noted after the final (fifth) vs. first dose. No clinically meaningful changes in blood count or chemistry values occurred after multiple CHE doses.

Clinical Significance: Dogs tolerated the 1:20 THC:CBD formulation well at low and medium doses, but clinically meaningful neurological signs were observed at high doses. Because of non-proportional increases in plasma cannabinoid concentrations with increasing doses, as well as potential differences in CHE product composition and bioavailability, the possibility of adverse events and dose regimen consistency should be discussed with dog owners.

Effect of Instructional Format on Veterinary Students' Task Performance and Emotional State during a Simulation-Based Canine Endotracheal Intubation Laboratory: Handout versus Video

Video- versus handout-based instructions may influence student outcomes during simulation training and competency-based assessments. Forty-five third-year veterinary students voluntarily participated in a simulation module on canine endotracheal intubation. A prospective, randomized, double-blinded study investigated the impact of video (n = 23) versus handout (n = 22) instructions on student confidence, anxiety, and task performance. Students self-scored their confidence and anxiety before and after the simulation. During the simulation laboratory, three raters independently evaluated student performance using a 20-item formal assessment tool with a 5-point global rating scale. No significant between- or within-group differences (p > .05) were found for both confidence and anxiety scores. Video-based instructions were associated with significantly higher (p < .05) total formal assessment scores compared with handout-based instructions. The video group had significantly higher scores than the handout group on 3 of the 20 individual skills (items) assessed: placement of tie to the adaptor-endotracheal tube complex (p < .05), using the anesthetic machine (p < .01), and pop-off valve management (p < .001). Inter-rater reliability as assessed by Cronbach's α (.92), and Kendall's W (.89) was excellent and almost perfect, respectively. A two-faceted crossed-design generalizability analysis yielded G coefficients for both the handout (E_p² = .68) and the video (E_p² = .72) groups. Video instructions may be associated with higher performance scores than handout instructions during endotracheal intubation simulation training. Further research into skill retention and learning styles is warranted.

Evaluation of a First-Year Veterinary Surgical Skills Laboratory: A Retrospective Review

A retrospective review of the first-year surgical skills competency-based assessment was performed at the Western College of Veterinary Medicine (WCVM) using 6 years of data from 475 students. The cumulative pass rate was 88.2% on first attempt and 99.2% upon remediation. Student gender did not influence overall pass/fail rates, with a failure rate of 11.1% for female students and 10.5% for male students (p = 0.88). Significantly decreased pass rates were associated with identification of the Mayo scissors (p = 0.03), explanation of using Allis tissue forceps (p = 0.002), and performance of a Lembert suture pattern (p < 0.01). An increased pass rate was observed for the cruciate pattern (p < 0.01). No differences were found in pass/fail rates for hand ties (p = 0.80) or instrument ties (p = 0.60). The most common errors occurred with half hitch ties: hand ties (53%) and instrument ties (38%). The most common errors were also recognized for instrument handling (31%) and needle management (20%) during the suture pattern section. The veterinary medical education community may benefit from the evidence-based findings of this research, in terms of understanding student performance across competencies, identifying areas requiring additional mentoring, and determining appropriate competencies for first-year veterinary students.

Circulating concentrations of glucagon-like peptide 1, glucose-dependent insulinotropic peptide, peptide YY, and insulin in client-owned lean, overweight, and diabetic cats

Our objectives were to measure plasma concentrations of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and peptide YY (PYY) in client-owned newly diagnosed diabetic cats and nondiabetic lean or overweight cats and to determine whether circulating concentrations of these hormones differed between study groups and if they increased postprandially as seen in other species. A total of 31 cats were recruited and placed into 1 of 3 study groups: lean (body condition score 4-5 on a scale of 1-9; n = 10), overweight (body condition score 6-8; n = 11), or diabetic (n = 10). Diabetics were newly diagnosed and had not had prior insulin therapy. Preprandial (fasting) and postprandial (60 min after meal) plasma hormone and glucose concentrations were measured at baseline and 2 and 4 wk. All cats were exclusively fed a commercially available high-protein and low-carbohydrate diet commonly prescribed to feline diabetic patients for 2 wk before the 2-wk assessment and continued through the 4-wk assessment. Results showed that plasma concentrations of GLP-1, GIP, PYY, and insulin increased in general after a meal in all study groups. Plasma PYY concentrations did not differ (P > 0.10) between study groups. Diabetics had greater plasma concentrations of GLP-1 and GIP compared with the other study groups at baseline (P < 0.05), and greater preprandial and postprandial GLP-1 concentrations than lean cats at 2 and 4 wk (P < 0.05). Preprandial plasma GIP concentrations were greater in diabetics than obese and lean (P < 0.05) cats at week 4. Postprandial plasma GIP concentrations in diabetics were greater than lean (P < 0.05) at week 2 and obese and lean cats (P < 0.05) at week 4. Together, our findings suggest that diabetic status is an important determinant of circulating concentrations of GLP-1 and GIP, but not PYY, in cats. The role of GLP-1, GIP, and PYY in the pathophysiology of feline obesity and diabetes remains to be determined.

Clinical phenotype of X-linked myotubular myopathy in Labrador Retriever puppies

Background

Seven male Labrador Retriever puppies from 3 different litters, born to clinically normal dams and sires, were evaluated for progressive weakness and muscle atrophy. Muscle biopsies identified a congenital myopathy with pathologic features consistent with myotubular myopathy. Further investigations identified a pathogenic mutation in the myotubularin gene, confirming that these puppies had X‐linked myotubular myopathy (XLMTM).

Objective

To review the clinical phenotype, electrodiagnostic and laboratory features of XLMTM in this cohort of Labrador Retrievers.

Results

Male puppies with XLMTM were small and thin compared with their normal littermates. Generalized weakness and muscle atrophy were present by 7 weeks of age in some puppies and evident to most owners by 14 weeks of age. Affected puppies stood with an arched spine and low head carriage, and walked with a short, choppy stride. Muscle atrophy was severe and progressive. Patellar reflexes were absent. Laryngeal and esophageal dysfunction, and weakness of the masticatory muscles occurred in puppies surviving beyond 4 months of age. Serum creatine kinase activity was normal or only mildly increased. EMG findings were nonspecific and included positive sharp waves and fibrillation potentials. Clinical signs progressed rapidly, with most affected puppies unable to walk within 3–4 weeks after clinical signs were first noticed.

Conclusions and Clinical Importance

Although initial clinical signs of XLMTM are similar to the phenotypically milder centronuclear myopathy in Labrador Retrievers, XLMTM is a rapidly progressive and fatal myopathy. Clinicians should be aware of these 2 distinct myopathies with similar clinical presentations in the Labrador retriever breed.

Cardiopulmonary effects of using carbon dioxide for laparoscopic surgery in cats

The cardiopulmonary effects of capnoperitoneum were investigated in 8 spontaneously breathing, young adult female cats undergoing laparoscopic pancreatic biopsy (intra-abdominal pressure 12 mmHg). Cats were premedicated with acepromazine and hydromorphone, induced with ketamine and diazepam, and maintained using an end-tidal isoflurane concentration of 1.13% in 100% oxygen. Direct systemic arterial blood pressure, heart and respiratory rates, end-tidal carbon dioxide (CO(2)), and isoflurane were recorded every 5 min before insufflation (baseline), during insufflation of the abdomen with CO(2), and following desufflation. Arterial blood samples were drawn at baseline, at 10 and 30 min of insufflation, and 5 min after desufflation for blood gases. The significant findings (P < 0.05) were as follows: insufflation produced an increase in heart rate (5 to 15 min and at 30 min), mean arterial blood pressure (25 to 30 min), and diastolic arterial blood pressure (10 to 30 min). After desufflation, respiratory rate increased for 15 min. The changes were within physiologically acceptable limits in these healthy, anesthetized cats despite no artificial maintenance of minute ventilation.

Granulocytic anaplasmosis in three dogs from Saskatoon, Saskatchewan

Three dogs from Saskatoon, Saskatchewan were diagnosed with acute granulocytic anaplasmosis. Fever, lethargy, inappetence, vomiting, diarrhea, and lameness were reported. Lymphopenia, thrombocytopenia, and splenomegaly were identified in all dogs. Inclusions were identified within the cytoplasm of blood neutrophils, and infection with Anaplasma phagocytophilum was confirmed by polymerase chain reaction.

Thrombin induces IL-6 but not TNFalpha secretion by mouse mast cells: threshold-level thrombin receptor and very low level FcepsilonRI signaling synergistically enhance IL-6 secretion

Mast cells become activated in multiple diseases wherein thrombin generation is often clinically apparent, but the effect of thrombin on cytokine release by mast cells remains unexplored. Thus, we examined IL-6 and TNFalpha release by thrombin-challenged mast cells. Thrombin and the protease-activated receptor (PAR)-1 peptide TRAP(14) induced these cells to secrete IL-6 in a dose-dependent fashion. Mast cells secreted > or =2800 pg IL-6/10(6) cells over 24 h, but only low levels of serotonin and no significant TNFalpha. Furthermore, at near-background levels of allergen, threshold doses of alpha-thrombin synergistically enhanced the IL-6 response (by up to 100-fold), but high-dose costimulation led to a simple additive response. Both the PI(3)- and sphingosine-kinase signaling pathways contributed importantly to the thrombin response. Our data thus clearly demonstrate that low-level thrombin and FcepsilonRI signaling can synergize to augment mast cell IL-6 responses, and that thrombin also differentially induces cytokine secretion by mast cells.