Browsing by Author "Larson, Martha M."

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    Bile duct obstruction associated with pancreatitis in 46 dogs
    Wilkinson, Ashley R.; DeMonaco, Stefanie M.; Panciera, David L.; Otoni, Cristiane C.; Leib, Michael S.; Larson, Martha M. (Wiley, 2020)
    Background: Pancreatitis is a common cause of extrahepatic bile duct obstruction (EHBDO) in dogs. Information describing the clinical course of dogs with pancreatitis associated bile duct obstruction (PABDO) is limited. Objectives: To describe the clinical course of PABDO in dogs and determine if presumed markers of disease severity are predictors of survival. Animals: Forty-six client-owned dogs with PABDO. Methods: A retrospective review of medical records from dogs diagnosed with PABDO was performed. Data, including clinical signs and biochemical changes, were collected 6 times throughout the course of disease. Outcome was defined as either survival (discharge from the hospital) or death. Results: Thirty-three (79%) out of 42 dogs with PABDO survived. Thirty-one (94%) of the 33 dogs that survived received medical management alone. Time from onset of clinical signs to initial documented increase in serum bilirubin concentration, peak bilirubin elevation, and initial decline in serum bilirubin concentration were 7 (median), 8, and 15 days, respectively. The median number of days from onset of clinical signs to outcome date was 13. Clinical signs of fever, vomiting, and anorexia were decreased in frequency from the onset of clinical signs to the time of peak bilirubin. Median bile duct dilatation at the time of ultrasonographic diagnosis of PABDO and peak bilirubin were not different between survivors (7.6 mm, 11.7 mg/dL) and nonsurvivors (6 mm, 10.6 mg/dL, P = .12, P = .8). Conclusions: Dogs with PABDO often have a prolonged course of illness and improve clinically despite biochemical evidence of progression of EHBDO.
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    Comparison of linear and volumetric criteria for the determination of therapeutic response in dogs with intracranial gliomas
    Garcia Mora, Josefa Karina; Robertson, John L.; Hsu, Fang-Chi; Shinn, Richard Levon; Larson, Martha M.; Rylander, Christopher G.; Whitlow, Christopher T.; Debinski, Waldemar; Davalos, Rafael V.; Daniel, Gregory B.; Rossmeisl, John H. Jr. (Wiley, 2022-05)
    Background: Brain tumor therapeutic responses can be quantified from magnetic resonance images (MRI) using 1- (1D) and 2-dimensional (2D) linear and volumetric methods, but few studies in dogs compare these techniques. Hypotheses: Linear methods will be obtained faster, but have less agreement than volumetric measurements. Therapeutic response agreement will be highest with the total T2W tumor volumetric (TTV) method. Therapeutic response at 6-weeks will correlate with overall survival (OS). Animals: Forty-six dogs with intracranial gliomas. Methods: Prospective study. Three raters measured tumors using 1D and 2D linear, TTV, and contrast-enhancing volumetric (CEV) techniques on 143 brain MRI to determine agreement between methods, define therapeutic responses, and assess relations with OS. Results: Raters performed 1D the fastest (2.9 ± 0.57 minutes) and CEV slowest (17.8 ± 6.2 minutes). Inter- and intraobserver agreements were excellent (intraclass correlations ≥.91) across methods. Correlations between linear (1D vs 2D; ρ >.91) and volumetric (TTV vs CEV; ρ >.73) methods were stronger than linear to volumetric comparisons (ρ range,.26-.59). Incorporating clinical and imaging data resulted in fewer discordant therapeutic responses across methods. Dogs having partial tumor responses at 6 weeks had a lower death hazard than dogs with stable or progressive disease when assessed using 2D, CEV, and TTV (hazard ration 2.1; 95% confidence interval, 1.22-3.63; P =.008). Conclusions and Clinical Importance: One-dimensional, 2D, CEV, and TTV are comparable for determining therapeutic response. Given the simplicity, universal applicability, and superior performance of the TTV, we recommend its use to standardize glioma therapeutic response criteria.
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    A comparison of radiography versus computed tomography in the diagnosis of middle ear disease in the dog
    Rohleder, Jacob John (Virginia Tech, 2004-04-14)
    The purpose of this study was to compare CT and radiography for diagnosing the presence and severity of middle ear disease in dogs with chronic otitis externa. Thirty-one dogs that were presented for a total ear canal ablation and bulla osteotomy were recruited. Three normal dogs served as controls. All dogs were examined using radiography and CT. Three radiologists independently evaluated imaging studies in random order. A visual analog scale method was used for scoring certainty and severity of middle ear disease. Surgical findings were recorded intra-operatively. Bulla lining samples were submitted for histopathology and scored by a single pathologist who also used a visual analog scale system. Findings from both modalities agreed more closely with surgical findings than with histopathology findings. With either surgery or histopathology as the gold standard, CT was more sensitive than and as specific as radiographs for predicting presence and severity of middle ear disease. Overall severity of middle ear disease was lower in the right versus the left ears. For CT, inter-observer variance of middle ear certainty was 217.04 while radiographic variance was 126.14 on the side with lower severity estimates. Both radiography and CT were more accurate for predicting the severity of the disease than its presence. Findings indicate that CT is more accurate and reliable than radiography in diagnosing middle ear disease for dogs with chronic otitis externa, but only when severity of disease is moderate or high. With low severity of disease, reader diagnostic certainty for both modalities becomes more variable.
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    Controlled cross circulation: effects on donor hemodynamics
    Kuntz, Charles A. (Virginia Tech, 1994-05-12)
    Controlled cross circulation was performed in six pairs of dogs to assess hemodynamic changes in the donor dog. Cardiopulmonary bypass was performed for 45 minutes, with an aortic cross clamp time of 3 5 minutes. Anesthesia was maintained in the donor dog with 1.8% end-tidal isoflurane. Parameters before and after controlled cross circulation were compared using a Wilcoxon Signed Rank Test. Donor left ventricular dP/dt max, pulmonary capillary wedge pressure, blood volume, systemic vascular resistance, heart rate, total protein, platelet count, and white blood cell count did not change significantly. Donor cardiac output, end diastolic volume, central venous pressure, stroke volume, mean arterial blood pressure, and packed cell volume all decreased significantly (p
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    Diagnostic Imaging of Foreign Bodies and Compartmentalization in the Canine Manus
    Ober, Christopher Patrick (Virginia Tech, 2009-03-17)
    Injury of the manus is an important cause of morbidity and function loss in dogs, especially working breeds. These injuries may cause foreign body retention and can lead to persistent infection. Accurate methods for diagnosis and localization of pathology in this anatomically complex region are critical to minimize patient morbidity, guide surgical planning, and improve case outcomes. The anatomy of the canine manus was evaluated with computed tomography (CT), magnetic resonance imaging (MRI), and transverse anatomic sections. Most structures identified on transverse sections were visible on both CT and MRI images. Detail in the osseous structures was better in CT images, while MRI provided increased contrast of soft-tissue structures. To test the hypothesis that diagnostic accuracies of CT, MRI, and ultrasound differ for detection of acute wooden foreign bodies in the canine manus, we inserted wooden splinters into canine cadaver manus and imaged each manus with all three modalities. Receiver operating characteristic curve analysis demonstrated that CT was most accurate for detection of acute wooden foreign bodies, followed in turn by ultrasound and MRI. Diseases in the human hand and foot are often confined by soft-tissue spaces, but similar structures have not been described in the dog. To determine if these spaces are present in the canine manus, we injected contrast medium into likely spaces and compartments in cadaver specimens, imaged the limbs with CT, and dissected the injected manus specimens. We found thirteen discrete soft-tissue spaces and five myofascial compartments that are similar to those described in the human hand. To test the hypothesis that spread of disease in the canine manus can be modeled and predicted, we injected cadaver interdigital web spaces with contrast medium, imaged them with CT, and dissected them. We found that the pattern of contrast agent spread, as a model of infection, was predictable and unique to the initial injection site. Findings from these cadaver studies improve our understanding of anatomy, imaging of wooden foreign bodies, and likely patterns of disease extension in the canine manus. Future studies are needed to test the utility of this information for surgical planning in affected clinical patients.
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    Diffusion Weighted MR Imaging in the Differentiation between Metastatic and Benign Lymph Nodes in Canine Patients with Head and Neck Disease
    Stahle, Jessica Anne (Virginia Tech, 2016-07-14)
    In dogs with large primary tumors, regional lymph node involvement or evidence of distant metastasis can have worse prognoses and significantly decreased survival. Lymph node size alone has been shown to be insufficient as a predictor for the accurate clinical staging of some canine neoplasia, including oral malignant melanoma. However, regional lymph nodes of the oral cavity, such as the medial retropharyngeal lymph nodes, are difficult to access for routine sampling. Diffusion weighted magnetic resonance imaging (DWI) has demonstrated the ability to differentiate metastatic from inflammatory/benign lymph nodes in clinical studies with human cancer patients through the calculation of quantitative values of diffusion termed apparent diffusion coefficients (ADC). The objective of this exploratory study was to evaluate DWI and ADC as potential future methods for detecting malignant lymph nodes in dogs with naturally occurring disease. We hypothesized that DWI would identify significantly different ADC values between benign and metastatic lymph nodes in a group of canine patients with head or neck disease. Our results demonstrated that two of four observers identified a significant difference between the mean ADC values of the benign and metastatic lymph nodes. When data from all four observers were pooled, the difference between the mean ADC values of the benign and metastatic lymph nodes approached but did not reach significance (P-value: 0.0566). Therefore, our hypothesis was not supported. However, DWI does show promise in its ability to differentiate benign from metastatic lymph nodes, and further studies with increased patient numbers are warranted
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    Echocardiographic Assessment of the Canine Right Heart: Reference Intervals and Repeatability
    Gentile, Jessica M. (Virginia Tech, 2012-01-27)
    Objectives: Phase 1) Establish echocardiographic reference intervals for measurements of the normal canine right heart. Phase 2) Describe the repeatability of normal right heart echocardiographic measurements. Phase 3) Describe the repeatability of right heart echocardiographic measurements which predict pulmonary artery pressure. Materials and Methods: Phase 1) 45 healthy adult dogs. Dogs underwent one echocardiographic examination by the same operator. Phase 2) 6 randomly selected dogs from the pool of Phase 1 dogs. Dogs underwent repeated echocardiograms by two operators. Phase 3) 4 client-owned dogs. Dogs underwent repeated echocardiographic examination by two operators. Results: Phase 1) The linear relationship between dimension and transformed body weight was highly variable. For linear dimensions, most of the scaling exponents were close to the theoretical value of 1/3. For area measurements, most of the scaling exponents were close to 2/3. Phase 2) Of the 168 within-day, between-day and between-operator coefficients of variation (CV) generated, 154 (91.7%) were below 15% and 135 (80.4%) were less than 10%. Phase 3) Of the 100 within-day, between-day and between-operator CVs generated, 72 (72%) were below 20% and 46 (46%) were below 10%. Conclusions: The right heart can be measured with relatively low repeatability. Measurement of the tricuspid regurgitation velocity should be the first priority when attempting to predict pulmonary artery pressure. If tricuspid regurgitation is not present, the use of transpulmonic acceleration time (AT) and the ratio of transpulmonic acceleration-to-ejection time (AT:ET) to indirectly assess pulmonary artery pressure is recommended.
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    Echocardiographic Investigation of Canine Myxomatous Mitral Valvular Disease
    Wesselowski, Sonya Rae (Virginia Tech, 2014-07-14)
    Objectives: To further characterize the echocardiographic anatomy of the canine mitral valve in healthy dogs and those affected by myxomatous mitral valve disease (MMVD), and to compare the level of agreement between two methods of assessment of left atrial size in identification of left atrial enlargement in dogs with MMVD. Animals: Sixty dogs with MMVD and 22 normal dogs were prospectively studied with 2-dimensional echocardiography. Methods: The length (AMVL), width (AMVW) and area (AMVA) of the anterior mitral valve leaflet and the diameter of the mitral valve annulus in systole (MVAs) and diastole (MVAd) were measured. Left atrial size was evaluated with the left atrial to aortic root ratio (LA:Ao) and by measuring left atrial volume indexed to body weight (LA Vol/BW). All patients were staged using published ACVIM guidelines and separated into groups B1 and B2/C. Results: Measurements of AMVL, AMVW, AMVA, MVAs and MVAd were all significantly greater in the B2/C group than in the control group. AMVW was significantly greater in group B1 than control. Twelve dogs had left atrial enlargement identified with LA Vol/BW that were considered normal using LA:Ao. Diagnostic disagreement between these two measurements was significant (P = 0.00012). The majority of dogs with diagnostic disagreement had concurrent echocardiographic evidence of more advanced mitral regurgitation. Conclusions: Relative to normal dogs, AMVL, AMVW, AMVA, MVAs and MVAd are greater in patients with advanced MMVD. LA Vol/BW may be superior to LA:Ao for identification of mild left atrial enlargement.
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    The Effect of Nephrotomy on Renal Function and Morphology in Normal Cats
    King, Michael David (Virginia Tech, 2006-05-02)
    Objective: To assess effects of bisection nephrotomy on renal function, size, and morphology in cats over a period of 12 weeks. Study Design: Controlled, randomized, blinded experiment. Sample Population: Ten adult female cats. Methods: Glomerular filtration rate (GFR), as determined by quantitative renal scintigraphy using 99mTc-DTPA, urinalysis, urine culture, and sonographic measurement of renal size were performed pre-operatively. A left or right nephrotomy (five randomly assigned cats in each group) was performed. Total and individual kidney GFRs were determined in each cat 2, 28 and 84 days post-operatively. Both kidneys were measured sonographically 28 and 86 days postoperatively and an ultrasound-guided biopsy of each kidney was obtained 86 days postoperatively. Results: No significant differences in mean GFR and kidney size of the operated versus un-operated kidneys were observed at any time period. Individual GFR and renal size of all except one of the cats remained within normal limits. Two additional cats had evidence of transient ureteral obstruction in the immediate post-operative period. No significant histologic abnormalities were observed in any biopsy. Conclusions: Bisection nephrotomy in normal cats did not adversely affect renal function or morphology over the three month post-operative period. Clinical Relevance: Bisection nephrotomy can be safely performed in normal feline kidneys without causing a significant deleterious effect on renal function. Studies in animals with pre-existing renal insufficiency are needed to insure no adverse effects would occur in clinical cases where this surgical procedure is warranted.
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    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.
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    Effects of Low and High Sodium Chloride Diets and Furosemide Administration on Cardiac Function, Plasma Electrolyte Concentrations, and the Renin-Angiotensin-Aldosterone System
    Swancott, Cindy Marie (Virginia Tech, 1998-04-14)
    Congestive heart failure is commonly treated with a low sodium diet and diuretic. The purpose of this treatment is the reduction of preload, or blood volume presented to the diseased cardiac muscle. The purpose of this study was to assess the roles of dietary sodium and furosemide on cardiac function, plasma electrolyte concentrations, and the renin-angiotensin-aldosterone system, in healthy canines. Twenty mixed-breed canines were allotted to one of four groups, Group I - Dogs fed low sodium diet (0.08% sodium), Group II - Dogs fed high sodium diet (1.0% sodium), Group III - Dogs fed low sodium (0.08%) and treated with furosemide (2 mg/kg orally (PO) every twelve hours (BID)), and Group IV - Dogs fed high sodium (1.0%) and furosemide ( 2 mg/kg PO BID). Cardiac function was assessed via echocardiography on days 0, 21,and 53. Plasma electrolyte concentrations were measured on days 0, 21, and 35. Activation of the renin-angiotensin-aldosterone system was evaluated on days 0, 21, 35, and 53. Low and high sodium diet with and without furosemide treatment did not alter cardiac function, plasma sodium, or plasma potassium concentrations. However, furosemide treatment combined with a low sodium diet resulted in the lowest plasma chloride concentrations, on days 21 and 35 (p<0.05). Furthermore, furosemide treatment resulted in significant alterations in the renin-angiotensin-aldosterone system, on days 21, 35, and 53, (p < 0.0001). Furosemide treatment significantly increased renin activity and aldosterone concentration. The interaction between furosemide and the low sodium diet yielded a greater increase in plasma renin activity and plasma aldosterone concentrations than furosemide administration with the high sodium diet. These results suggest direct activation of the renin-angiotensin-aldosterone system by furosemide. Future research is warranted in congestive heart failure subjects, due to the adverse affects of decreased plasma chloride concentrations and activation of the renin-angiotensin-aldosterone system.
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    The Effects Of Mercuric Chloride On Cultured Atlantic Spotted Dolphin (Stenella Plagiodon) Renal Cells And The Role Of Selenium In Protection
    Wang, Amy (Hui-Shan) (Virginia Tech, 1998-04-24)
    Marine mammals are known for their low susceptibility to mercury toxicity, and it was hypothesized that selenium may play a role in protection against mercury toxicity. To gain insight into the mechanisms of the low susceptibility of cetaceans, we investigated the in vitro effects (1) of mercuric chloride (HgCl₂) on the ultrastructure and cell death of Atlantic spotted dolphin renal cells (Sp1K cells), (2) of HgCl₂ on the cell proliferation and cell cycle status of Sp1K and Rhesus monkey renal cells (MK2), and (3) of sodium selenite (Na₂SeO₃) on cell proliferation and cell death of control and HgCl₂-treated Sp1K cells. HgCl₂ affected multiple organelles and nuclei in Sp1K cells, and induced apoptosis in a time-and dose-dependent manner. Both ultrastructural changes and induction of apoptosis were milder than seen in other cell types in previous publications. In addition, Sp1K cells were able to proliferate at 25 µM HgCl₂ while MK2 cells were killed at 15 µM HgCl₂. An increase in percentage of cells in the G0/G1 phase in the cell cycle and a decrease in S, and G2/M phase cells were seen in Sp1K cells exposed to more than 10 uM HgCl₂ more than 72 hours. MK2 cells showed cell cycle changes only at 24 hours exposure, and may be due to a sensitive subgroup. These data suggested that Sp1K cells were less susceptible than other cell types in a cell-specific way, which was independent of selenium protection. Concurrent exposure to Na₂SeO₃ provided protection against the HgCl₂-induced decrease in cell proliferation of Sp1K. The protective effects were greater if Na₂SeO₃ and HgCl₂ were premixed, but disappeared if exposures did not overlap. Although pretreatments with Na₂SeO₃ alone did not provide protection, they increased the protection of selenium administered later. Furthermore, Na₂SeO₃ decreased HgCl₂-induced apoptosis. These data demonstrated the Na₂SeO₃ protection against HgCl₂ toxicity in Sp1K cells in terms of cell proliferation and apoptosis. This study is the first report that reveals the existence of mercury-selenium antagonism in cultured cetacean cells. The data supported the hypothesis that selenium protection against mercury toxicity is, at least partially, through competition of binding sites and formation of mercury-selenium complex.
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    Evaluation of gallbladder motility assessed by ultrasonography in dogs with hyperlipidemia
    Villm, Jessica A.; DeMonaco, Stefanie M.; Panciera, David L.; Larson, Martha M.; Bolton, Timothy A. (Wiley, 2023-05)
    Background: The pathogenesis of gallbladder (GB) mucoceles in dogs is unknown. It has been proposed that hyperlipidemia could impair GB motility and contribute to GB mucocele formation. Hypothesis/Objectives: The objective of this study was to compare GB motility in dogs with hyperlipidemia to control dogs using ultrasonography. We hypothesized that hyperlipidemic dogs will have decreased GB motility compared with controls. Animals: Twenty-six hyperlipidemic and 28 healthy, age-matched control dogs were prospectively enrolled. Methods: Cholesterol and triglyceride concentrations were measured in all dogs. Hyperlipidemia was defined as hypercholesterolemia (>332 mg/dL) and/or hypertriglyceridemia (>143 mg/dL) using a biochemical analyzer. Ultrasound was performed before feeding, and 60 and 120 minutes after ingestion of a high fat diet. Gallbladder volumes (GBV) and ejection fractions (EF) were calculated. Results: Hyperlipidemic dogs had significantly larger GBVs (ml/kg) before feeding and 60 minutes after feeding of 1.2 (0.4-7.5; P = .008) and 0.6 (0.1-7.2; P = .04) compared with controls 0.6 (0.2-2.6) and 0.4 (0.1-1.9), respectively. Severely hyperlipidemic dogs had significantly larger GBV at baseline, 60 minutes, and 120 minutes of 1.7 (0.6-7.5; P = .03), 1.3 (0.4-7.2; P = .02), and 1.3 (0.2-8.2; P = .04), respectively compared with mildly hyperlipidemic dogs. EFs at 60 and 120 minutes between controls, hyperlipidemic, and severely hyperlipidemic were all 0.3 at 60 minutes and 0.5, 0.3, and 0.3 at 120 minutes, respectively which were not statistically different. Conclusions and Clinical Importance: Hyperlipidemia leads to GB distention in dogs which could lead to retention of bile and gallbladder disease.
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    Evaluation of Thyroid to Background Ratios in Hyperthyroid Cats
    Bettencourt, Ann Elizabeth (Virginia Tech, 2014-07-17)
    Hyperthyroidism is the most common feline endocrinopathy. 131I is the treatment of choice, and over 50,000 cats have been treated using an empirical fixed dose. Better treatment responses could be achieved by tailoring the dose based on the severity of disease. Scintigraphy is the best method to quantify the severity of the disease. Previously established scintigraphic quantitative methods, thyroid to salivary ratio (T:S ratio) and % dose uptake, are the most widely recognized measurements. Recently, the thyroid to background ratio (T:B ratio) has been proposed as an alternate method to assess function and predict 131I treatment response. The purpose of this study was to determine the best location of a background ROI, which should be reflective of blood pool activity. We also hypothesized that the T:B ratio using the determined background ROI would provide improved correlation to T4 when compared to T:S ratio and % dose uptake in hyperthyroid cats. Fifty-six hyperthyroid cats were enrolled. T4 was used as the standard measure of thyroid function and was obtained prior to thyroid scintigraphy and 131I therapy. Blood samples were collected at the time of scintigraphy and radioactivity within the sample was measured. The plasma radioactivity was compared to the background ROI count densities in 8 anatomic regions using linear regression analysis for 55 cats. One cat was excluded from the study because of an injection error during scintigraphy. T:B and T:S ratios, and % dose uptake on scintigraphy were then compared to serum T4 by linear regression analysis for 39 cats. Sixteen cats were excluded because of recent methimazole or Y/D diet use, or incomplete data. The heart ROI correlated best to plasma pertechnetate activity (r = 0.70). % dose uptake correlated best to serum T4 (r = 0.74), followed by T:S ratio (r = 0.66), followed by the T:B ratio using the heart ROI (r = 0.59). Placing an ROI over the heart is the best method of quantifying plasma radioactivity. T:B ratio using the heart ROI as the background is a good predictor T4 but percent dose uptake and T:S ratio proved to be better predictors of T4 than any of the T:B ratios. Therefore, our hypothesis was not supported. The T:B ratio may not provide the best scintigraphic measurement of thyroid function. Hence it is unlikely to accurately predict treatment response to 131I therapy.
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    Experimental Evaluation of Urinary Bladder Marsupialization in Male Goats
    May, Kimberly Anne (Virginia Tech, 1999-07-13)
    Urinary bladder marsupialization has been successful in producing acceptable long-term resolution of clinical cases of obstructive urolithiasis in male goats. The purpose of this study was to evaluate the six-month outcome of urinary bladder marsupialization in male goats. The urinary bladders of six male goats free from systemic disease were marsupialized following induced urethral obstruction. Renal ultrasonography, complete blood count, and blood chemistry analysis were evaluated preoperatively (day 0), at 7 postoperative days, and at 30-day intervals until 180 postoperative days. Stomal diameter was recorded at each interval. Necropsy examination was performed on day 180 or when stomal stricture or death occurred. Stomal stricture occurred in one goat at 120 days, and another goat was found dead at 150 days. Necropsy of this goat revealed severe, suppurative cystitis. All goats developed mild urine scald dermatitis. All blood chemistry values remained within normal limits. Significant decreases in white blood cell count, serum creatinine, and stomal diameter were observed from day 0 to day 180. Except for the goat that died at 150 days, all urinary bladders were tubular in shape and the mucosa and serosa of all urinary tract organs appeared grossly normal at necropsy examination. Histologic evidence of chronic suppurative cystitis and chronic, mild, lymphoplasmacytic pyelitis was present in all goats. Culture of renal tissue yielded bacterial growth in three of six goats, and culture of a swab of the urinary bladder mucosa yielded bacterial growth in all animals. Although clinical signs of ascending urinary tract infection were not observed in goats with patent stomata, urinary bladder marsupialization may result in ascending inflammation or infection. Based upon the results of this study, urinary bladder marsupialization should be recommended with caution as the primary procedure in clinical cases.
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    Gross and Microscopic Observations on the Lingual Structure of the West Indian Manatee (Trichechus manatus latirostris)
    Levin, Milton Jay (Virginia Tech, 2004-03-19)
    The West Indian manatee tongue was examined macroscopically, light microscopically, and electron microscopically (scanning and transmission). The tongue was slender, muscular, and firmly fixed in the oral cavity. Only the cranial tip was free and mobile. Numerous filiform papillae were distributed over the dorsal surface of the rostral lingual region. Caudal to the filiform papillae, multiple raised, round papillae were distributed over the majority of the dorsum. Fungiform papillae were restricted to the lateral margins of the tongue. Caudally, the dorsal and lateral regions showed numerous open fossae and pits. Microscopic examination showed the majority of the lingual dorsum to be covered with a thick stratified squamous epithelium. The caudal dorsal and lateral open pits led to well-developed mucous salivary glands. Foliate papillae, located on the caudal region of the tongue, contained taste buds embedded in the epidermis. Glands within the foliate papillae were mostly mucous, though some seromucous glands were evident. Throughout the tongue, striated muscle was abundant below the epidermis. Blood vessels, lymph channels, and nerve fibers were freely distributed throughout the intermuscular stroma. Nerve fibers reacted positively with neuron specific enolase antibody throughout the lingual structure, including nerve bundles, muscle bundles, glands, and taste buds. Electron microscopy revealed cytoplasmic vacuoles juxtaposed to the nucleus in the stratum spinosum of the foliate papillary region.
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    Histotripsy Ablation in Preclinical Animal Models of Cancer and Spontaneous Tumors in Veterinary Patients: A Review
    Hendricks-Wenger, Alissa; Arnold, Lauren; Gannon, Jessica; Simon, Alex; Singh, Neha; Sheppard, Hannah; Nagai-Singer, Margaret A.; Imran, Khan Mohammed; Lee, Kiho; Clark-Deener, Sherrie; Byron, Christopher R.; Edwards, Michael R.; Larson, Martha M.; Rossmeisl, John H. Jr.; Coutermarsh-Ott, Sheryl; Eden, Kristin; Dervisis, Nikolaos G.; Klahn, Shawna L.; Tuohy, Joanne L.; Allen, Irving C.; Vlaisavljevich, Eli (IEEE, 2021-09-03)
    New therapeutic strategies are direly needed in the fight against cancer. Over the last decade, several tumor ablation strategies have emerged as stand-alone or combination therapies. Histotripsy is the first completely noninvasive, nonthermal, and nonionizing tumor ablation method. Histotripsy can produce consistent and rapid ablations, even near critical structures. Additional benefits include real-time image guidance, high precision, and the ability to treat tumors of any predetermined size and shape. Unfortunately, the lack of clinically and physiologically relevant preclinical cancer models is often a significant limitation with all focal tumor ablation strategies. The majority of studies testing histotripsy for cancer treatment have focused on small animal models, which have been critical in moving this field forward and will continue to be essential for providing mechanistic insight. While these small animal models have notable translational value, there are significant limitations in terms of scale and anatomical relevance. To address these limitations, a diverse range of large animal models and spontaneous tumor studies in veterinary patients have emerged to complement existing rodent models. These models and veterinary patients are excellent at providing realistic avenues for developing and testing histotripsy devices and techniques designed for future use in human patients. Here, we provide a review of animal models used in preclinical histotripsy studies and compare histotripsy ablation in these models using a series of original case reports across a broad spectrum of preclinical animal models and spontaneous tumors in veterinary patients.
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    Microanatomic structure of cetacean skin in the urogenital region
    Jones, Flynn Margaret (Virginia Tech, 1993-08-05)
    It was hypothesized that there may be microanatomic specializations in the urogenital slit and mammary region of cetaceans. There may be an integumentary-linked mechanism in these animals similar to that which causes the milk let-down response in terrestrial mammals. This hypothesis was tested on tissue samples from fourteen animals collected in a standardized array of fourteen samples from the urogenital area, and one each from the ventral aspect of the flipper and the mid-dorsal body wall for comparison. Using standard histological and ultrastructural procedures, including both transmission and scanning electron microscopy, tissues from nine species were investigated. These included the bottlenose dolphin (Tursiops truncatus), striped dolphin (Stenella coeruleoalba), harbor porpoise (Phocoena phocoena), pygmy sperm whale (Kogia breviceps), short and long finned pilot whales (Globicephala macrorhynchus and malaena respectively), beluga whale (Delphinapterus leucas), humpback whale (Megaptera novaeangliae), and fin whale (Balaenoptera physalus). Measurements were taken of the height of the epidermis, the thickness of the epidermal stratum externum, and the height and number of dermal papillae. Co1lagen bundles of the reticular dermis were measured and ranked by diameter. Nervous structures were quantitatively evaluated by type and location. No differences were found in the epithelial, connective, or nervous tissue of the skin in this region that would imply an increased sensitivity in this area. However, an observed unique organization of the connective tissue may imply a functional difference in the skin of the urogenital region unrelated to the milk let-down phenomenon. Possible alternative mechanisms for the initiation of milk let-down in cetaceans are discussed, including myoepithelial cell contraction caused by urogenital bumping by calves, vocalization by calvest and tacto/acoustic stimulation of the urogenital area by the calf. Epidermal thickness and papillary height varied among animals of different cetacean species, although there seemed to be a structural 'formula' applicable to the skin of all cetaceans that would permit efficient turnover of the epidermis. The significance of integumentary lipids is discussed. Deviations in cellular and subcellular structures of cetacean skin from those described in previous reports are mentioned, and a previously undescribed location for nerves in dermal papillae was revealed.
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    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.
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    Quantitative Pertechnetate Thyroid Scintigraphy and the Ultrasonographic Appearance of the Thyroid Gland in Clinically Normal Horses
    Davies, Sarah Elizabeth (Virginia Tech, 2010-04-28)
    The purpose of this study was to report the scintigraphic and sonographic appearance of the thyroid gland in clinically normal horses so these modalities could be used to assess the thyroid gland in this species. Horses were divided into two age groups. Group A consisted of 8 horses between 3 and 10 years of age and Group B of 7 horses between 11 and 20 years of age. Total T4 concentrations were within the laboratory reference interval. Thyroid to salivary (T/S) ratio, percent dose uptake of pertechnetate and thyroid lobe volume were calculated. Echogenicity of thyroid lobes and presence of nodules were documented. The two groups were compared using appropriate parametric and nonparametic tests. Total T4 concentrations were significantly lower in the older group. Sixty minute mean ± standard deviation (SD) T/S ratios for older versus younger horses were 5.8 ± 3.0 and 5.3 ± 2.2, respectively. Sixty minute median and interquartile ranges for percent dose uptake of pertechnetate for older versus younger horses were 3.64% (1.5 to 3.98%) and 2.55% (2.33 to 2.90%), respectively. Mean ± SD thyroid lobe volumes for older versus younger horses were 18.93 ± 5.16 cm3 and 13.55 ± 3.56 cm3, respectively. Most thyroid lobes were hyper or isoechoic to the sternocephalicus muscle. Prevalence of thyroid nodules did not differ between groups. Older horses had trends for greater T/S ratios, percent dose uptakes and thyroid lobe volumes but had lower total T4 concentrations. Further studies using scintigraphy and ultrasound in horses with thyroid disease are planned.