Browsing by Author "Demonaco, Stefanie"

Now showing 1 - 7 of 7
  • Thumbnail Image
    ADAMTS13 Activity in Dogs with Chronic Enteropathies
    Barth, Samantha Irene (Virginia Tech, 2023-09-01)
    Background: Chronic enteropathies (CE) predispose dogs to thromboembolic disease, but the underlying mechanisms are poorly understood. Humans with CE have decreased activity of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), a von Willebrand factor (vWF) cleaving enzyme, and increased circulating vWF. The primary aim of this study is to assess plasma ADAMTS13 activity, vWF antigen (vWF:Ag) concentration, and vWF collagen binding activity (vWF:CBA) in dogs with CE. Hypotheses: Dogs with CE have reduced plasma ADAMTS13 activity, increased vWF:Ag, and increased vWF:CBA compared to healthy control dogs. Animals: Twenty privately-owned dogs with CE and 40 healthy dogs were recruited from a specialty hospital population. Methods: Prospective observational study. Dogs were confirmed to have CE using histopathology. ADAMTS13 activity was measured using a commercially available ELISA kit (DiapharmaⓇ) in 20 dogs with CE and 40 healthy control dogs. Plasma vWF:Ag was assessed in 20 dogs with CE and 20 healthy control dogs. Plasma vWF:CBA was assessed in 19 dogs with CE and 20 healthy control dogs. For statistical analysis, an unpaired t-test was used for normally distributed data and Wilcoxon rank sum was used for non-Gaussian distribution. Significance was set at P < 0.05. Results: Plasma ADAMTS13 activity and vWF:Ag were not significantly different compared to healthy dogs (P = 0.07, P = 0.16, respectively). Plasma vWF:CBA was significantly decreased compared to healthy dogs (P = 0.007). Conclusions and clinical relevance: Plasma ADAMTS13 activity was not significantly different in dogs with CE compared to healthy dogs and is unlikely to be the primary mechanism for hypercoagulability associated with CE. Forty-three percent of CE dogs with hypoalbuminemia had ADAMTS13 activity below reference interval. Further studies are warranted to evaluate ADAMTS13 activity in a subset of dogs with CE, including those with protein losing enteropathy and thromboembolism.
  • Thumbnail Image
    Determining ideal staple size for small intestinal surgery in cats
    Hiebert, Elizabeth C. (Virginia Tech, 2022-03-08)
    Background: The use of stapling equipment for intestinal surgery in cats is rarely reported, and appropriate staple sizes for cat intestine are unknown. Objective: To determine staple cartridge sizes for thoracoabdominal (TA) and endoscopic gastrointestinal anastomosis (EndoGIA) that will simultaneously prevent leakage of small intestinal contents while also allowing for sufficient vascular permeability past the staple lines for intestinal healing. Methods: Two sizes of EndoGIA cartridges (2.0/2.5/3.0mm and 3.0/3.5/4.0mm) and two sizes of TA cartridges (2.5mm and 3.5mm), applied in a transverse manner across fresh cadaveric cat jejunum, were evaluated via intestinal burst pressure testing for maximum intraluminal pressure prior to leaking, and via infusion of an intravascular dye at normal arterial pressures to determine percentage of vascular patency past the staple lines. Vascular patency was compared not only from pre-and post-staple segments of the same intestinal sample, but also EndoGIA vascular patency was evaluated against TA vascular patency. Results: Two cats met study criteria. All samples had intraluminal burst pressures over twice the chosen minimum (of 30mmHg). Vascular patency post- staple line ranged from 0-90.8%, with the most consistently high numbers noted with the TA 3.5mm cartridges. No EndoGIA cartridge had a post- staple line vascular patency higher than 31.1%, and no intravascular dye was noted in any post- staple line sample in the EndoGIA 2.0/2.5/3.0mm group. Conclusions: While statistical analysis of the dataset was unable to be performed due to low numbers of samples for comparison, both intestinal intraluminal burst pressure trends and intravascular dye patterns suggested both the TA 3.5mm cartridge and (to a lesser extent) the 3.0/3.5/4.0mm EndoGIA cartridge could provide the ideal combination of intraluminal seal without restriction of vascular access for healing. The intravascular dye infusion technique, developed during this research, shows promise as a future instrument to determine vascular patterns around intestinal implants in cadaveric cat specimens.
  • Thumbnail Image
    Effects of hyperlipidemia on gallbladder motility in dogs
    Villm, Jessica Ann (Virginia Tech, 2021-07-16)
    Background: The pathogenesis of gallbladder mucocele is unknown in the dog. It has been proposed that hyperlipidemia could impair gallbladder motility and contribute to gallbladder mucocele formation. Objectives: The objective of this study was to compare gallbladder motility in dogs with hyperlipidemia to healthy, control dogs using ultrasonography. We hypothesized that hyperlipidemic dogs have decreased gallbladder motility, defined by increased fasting gallbladder volume (GBV) and decreased gallbladder ejection fractions at 60 (EF60) and 120 minutes (EF120) compared to controls. Animals: 26 hyperlipidemic dogs, 28 healthy control dogs Methods: Twenty-six hyperlipidemic and 28 healthy, age-matched control dogs were prospectively enrolled. Hyperlipidemia was defined as hypercholesterolemia (>332 mg/dL) and/or hypertriglyceridemia (>143 mg/dL). Dogs with both primary and secondary causes of hyperlipidemia were included. All dogs were fasted for at least 12 hours prior to collection of plasma biochemistry and pre-prandial ultrasound. Ultrasound was performed on dogs in the fasted state as well as at 60 and 120 minutes after being fed 10g/kg of a high fat diet (Hill's a/d diet; Hill's Pet Nutrition, Topeka, Kansas, USA). GBVs and EFs were calculated using the following formulas: GBV = (0.52 x L x W x H)/kg and EF = ((GBV0- GBV60,120)/GBV0) x 100, respectively. GBV0, GBV60, GBV120, EF60 and EF120 were compared between dogs with hyperlipidemia and controls using the Wilcoxon rank sum test. Statistical significance was set to p<0.05. Results: Hypercholesterolemia and hypertriglyceridemia were present in 15/26 (58%) and 21/26 (81%) hyperlipidemic dogs, respectively and 10/26 (38%) had elevations in both parameters. The median age in both groups was 10 years. Median (range) cholesterol concentration was 346 mg/dL (181-1372 mg/dL) and 238 mg/dL (153-324) in hyperlipidemic and control dogs, respectively. Median triglyceride concentration was 330 mg/dL (52-2213) and 65.5 mg/dL (32-142) in hyperlipidemic and control dogs, respectively. Eleven (42%) hyperlipidemic dogs were considered severely hyperlipidemic based on the triglyceride and/or cholesterol concentrations above 500 mg/dL. There were significant differences in GBV0 and GBV60 between hyperlipidemic and control dogs. Dogs with severe hyperlipidemia had significantly larger GBVs at all time points. Dogs with hypercholesterolemia also had significantly greater GBVs at all times compared to dogs without hypercholesterolemia. Median EF60 and EF120 were not significantly different between hyperlipidemic and control dogs nor severely hyperlipidemic and mildly hyperlipidemic dogs. Conclusions: Hyperlipidemic dogs have significantly greater fasting and postprandial GBVs but similar ejection fractions when compared to control dogs. Gallbladder emptying is unaltered in hyperlipidemic dogs, but gallbladder volume is higher in hyperlipidemic dogs after feeding. This distention could contribute to bile retention of bile and potentially gallbladder disease.
  • Thumbnail Image
    Evaluation of hemostasis in hyperthyroid cats
    Keebaugh, Audrey Elizabeth (Virginia Tech, 2020-07-17)
    Background: Hyperthyroid cats are predisposed to thrombus formation. The mechanism for thrombogenesis is currently unknown, but could be associated with altered hemostasis as seen in hyperthyroid humans. Objective: The purpose of this study was to evaluate markers of hemostasis in hyperthyroid cats compared to healthy cats, and in hyperthyroid cats before and after treatments with radioactive iodine (RIT). Methods: Twenty-five cats with hyperthyroidism and 13 healthy euthyroid cats > 8 years of age were studied. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, antithrombin (AT), D-dimers, thrombin-antithrombin complexes (TAT), von Willebrand Factor antigen (vWF:Ag), and activity of factors VIII and IX were measured. An echocardiogram was performed in all cats and healthy cats with abnormal echocardiograms were excluded. Measurements of hemostasis were evaluated again in 7 cats > 6 months after RIT and deemed to have restored euthyroid status. Results: There is a significant likelihood of being in hypercoagulable state based on hyperthyroid state (P = 0.019) and serum T4 level is significantly associated with predicating hypercoagulability (P = 0.043). Hyperthyroidism is associated with significantly higher median fibrinogen concentration (P < 0.0001), higher median AT activity (P < 0.0001), and higher median vWF:Ag level (P = 0.01) with all values decreasing significantly post-RIT. Fibrinogen and AT had a strong positive correlation with serum T4 value (r = 0.79; 95% CI 0.63 - 0.89 and r = 0.70; 95% CI 0.50 - 0.84, respectively). Presence of an abnormal echocardiogram in hyperthyroid cats was associated with a significantly higher median fibrinogen concentration (P = 0.03). Echocardiographic status did not have a significant impact on the remaining hemostatic markers in hyperthyroid cats. Conclusions: These results provide evidence of altered hemostasis and hypercoagulability in hyperthyroid cats that do not appear to be solely attributed to cardiac abnormalities. These differences of altered hemostasis resolved after radioiodine therapy, but further studies are warranted to determine if hypercoagulable state resolves.
  • Thumbnail Image
    Measurement of Pre and Postprandial Urine Calcium to Creatinine Ratio to Identify Calcium Oxalate Urolithiasis in Miniature Schnauzers
    Carr, Susan Venn (Virginia Tech, 2018-06-25)
    The intent of this research is to identify a simple diagnostic test to detect abnormal calciuresis and predict calcium oxalate (CaOx) urolith presence in Miniature Schnauzers. We investigated the impact of postprandial time on the specificity of urine calcium:creatine (UCa/Cr) in identifying affected dogs. The hypotheses were: 1) Significant differences exist in fasted and postprandial UCa/Cr between urolith-forming and control schnauzers. 2) UCa/Cr increases significantly from fasted baseline at one or more postprandial time point(s). Urine samples were collected from Miniature Schnauzers with (urolith-formers) and without (controls) CaOx uroliths in a fasted state and 1, 2, 4, and 8 hours after feeding a standardized diet. The change in UCa/Cr from baseline was calculated for each postprandial time. Urolithiasis status and the time point were assessed for impact on the UCa/Cr and change in UCa/Cr using a mixed model ANOVA. Based on 9 urolith-forming and 15 control dogs enrolled, urolith-forming Miniature Schnauzers have significantly higher mean UCa/Cr at 1 hour and 8 hours postprandial timepoints indicating altered calciuresis. The change in UCa/Cr was not significant at any post-prandial time point between or within groups. This pilot study shows male urolith-forming Miniature Schnauzers have excessive calciuresis throughout the day, providing insight into the mechanism behind their formation of CaOx uroliths. If using the Ca/Cr ratio, the postprandial sampling time is not critical. This simple urine measurement has potential as a marker of urolith presence and possibly risk of urolith formation.
  • Thumbnail Image
    Natural History of Biliary Sludge in Dogs
    Demonaco, Stefanie (Virginia Tech, 2015-08-27)
    Background: Biliary sludge is associated with gallbladder (GB) dysmotility and mucus hypersecretion suggesting that these factors could lead to GB mucoceles. If biliary sludge does progress to GB mucoceles, treatments to reduce the production and progression of sludge are warranted. Objectives: The aim of this study was to determine the natural history of biliary sludge in dogs. Animals: Healthy, client-owned dogs (n=74) screened for biliary sludge; 42 affected dogs identified Methods: Prospective, observational design. Serial ultrasound examinations and biochemistries were evaluated over 1 year. The following were determined: percentage of the GB filled with sludge (mild (0.01%-24.4%), moderate (24.5%-49.4%), moderate to severe (49.5%-74.4%), severe (74.5%-100%)), gravity dependency of sludge, GB dimensions, and biochemical indices (ALT, GGT, ALP, total bilirubin, albumin, total calcium, triglycerides, and cholesterol). Mixed model ANOVA, Friedman chi-square, Mantel-Haenzsel chi-square tests, and Kruskal-Wallis test were performed to detect significant changes in these parameters. Significance at P <0.05. Results: After 1 year of follow-up, the percentage of the GB filled by sludge was mild (34%), moderate (47%), moderate to severe (13%), severe (3%), or absent (3%) with no significant difference in the median degree of biliary sludge within 1 year (P=0.36). There was no significant change in the gravity dependency of sludge over 1 year. Dogs had resolved (2%), decreased (19%), static (40%), increased (29%), or recurrent (10%) sludge at the conclusion of the study. Biochemical indices or GB volume were not significantly different over time or among groups. Conclusion: Biliary sludge is prevalent, affected dogs remain asymptomatic, and it rarely resolves in healthy dogs over a period of 1 year. Some dogs developed non-gravity dependent sludge within 1 year, which may indicate changes in consistency.
  • Thumbnail Image
    Platelet Function in Dogs with Chronic Liver Disease
    Wilkinson, Ashley R. (Virginia Tech, 2019-06-10)
    Background: Dogs with acquired chronic liver disease often have hemostatic derangements. It is currently unknown whether dogs with acquired chronic liver disease have decreased platelet function and alterations in von Willebrand factor (vWF) that may contribute to hemostatic abnormalities. Hypothesis: Dogs with chronic liver disease have prolonged platelet closure time (CT), assessed with the PFA-100®, and buccal mucosal bleeding time (BMBT), and increased vWF concentration compared to healthy dogs. Animals: Eighteen dogs with chronic acquired liver disease undergoing ultrasound-guided needle biopsy of the liver or laparoscopic liver biopsy and eighteen healthy age-matched control dogs. Methods: Prospective study. BMBT, CT using the PFA-100®, and vWF antigen were measured in dogs with chronic liver enzyme elevation undergoing ultrasound-guided needle biopsy of the liver or laparoscopic liver biopsy. After undergoing ultrasound-guided needle biopsy, dogs were monitored for hemorrhage with serial packed cell volume measurements and focused assessment with sonography. An unpaired t-test was used for normally distributed data and the Mann-Whitney test was used when non-Gaussian distribution was present. The level of significance was set at P <0.05. Results: The CT was not different between the two groups (P = 0.27). The BMBT was significantly longer in the liver disease group compared to the control group (P = 0.019). There was no difference in the mean vWF antigen of the two groups (P = 0.077). Conclusions and clinical relevance: These results demonstrate mild impairment of primary hemostasis in dogs with chronic liver disease based on prolongation of BMBT.