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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

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. Master of Science In feline hyperthyroidism, there is a predisposition for thrombus formation. An alteration of hemostasis has been documented in hyperthyroid humans, but despite reports of thrombus formation in hyperthyroid cats, the underlying mechanism is currently unknown. Hyperthyroidism can lead to cardiac abnormalities that could possibly contribute thrombus formation, although thrombus formation has occurred in hyperthyroid cats without detected abnormalities. The goal of this study was to evaluate markers of hemostasis in hyperthyroid cats presenting for radioiodine therapy to evaluate for presence of hypercoagulability. Twenty-five hyperthyroid cats were evaluated with hemostasis panels and echocardiograms. The results were compared to a group of 13 healthy cats. Markers of hemostasis and echocardiograms in 7 hyperthyroid cats were also compared to results 6 months or greater post-radioiodine therapy. There was evidence of altered hemostasis and hypercoagulability in hyperthyroid cats. The alterations noted resolved after radioiodine therapy and do not appear to be solely attributed to cardiac abnormalities seen in hyperthyroid cats.

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

Background: Radioiodine is the treatment of choice for feline hyperthyroidism. The ideal method of dose determination of 131I remains controversial. Objective: To compare a method of radioiodine dose determination that utilized thyroid scintigraphy with a standard fixed dose for treatment of feline hyperthyroidism. Methods: Fifty-seven and 23 cats were in the novel and fixed dose groups, respectively. Cats with a percent dose uptake as determined using 99mTcO4- uptake on thyroid scintigraphy 10% were designated to receive 3 mCi, 3.5 mCi, or 4.5 mCi of 131I, respectively, administered subcutaneously. Radioiodine dose was adjusted by thyroid size, determined by evaluating the thyroid:salivary size ratio (T:S) and categorized as 10. If the thyroid size fell into a higher dosing category than percent uptake, the dose was increased accordingly. Cats in the fixed dose group received 4.5 mCi of 131I. Six months after treatment, cats were determined to be euthyroid, hypothyroid, or hyperthyroid based on serum T4 concentrations relative to an established reference interval. Univariate analysis using Chi-square was used to determine associations between treatment and outcome. Results: There was no difference in outcome between the novel and fixed dose treatments. Euthyroidism, hypothyroidism, and hyperthyroidism developed in 61, 30, and 9% of cats in the fixed dose group, respectively compared to 58, 26, and 16% in the novel dose group. Conclusions: A modified fixed dose method of radioiodine based upon thyroid size and percent dose uptake was ineffective in improving outcomes over a standard fixed dose method. Master of Science

Background: Because of the vague clinical signs and limitations of thyroid function tests, misdiagnosis of hypothyroidism in dogs is common and leads to inappropriate treatment with levothyroxine. Chronic supplementation can suppress the hypothalamic-pituitary-thyroid axis (HPTA) and make it difficult to assess thyroid function following withdrawal of levothyroxine. Objectives: To determine if the HPTA is suppressed following levothyroxine administration in euthyroid dogs and the time required for resolution of any suppression. Animals: Twenty-eight healthy euthyroid dogs Methods: A prospective randomized study administering levothyroxine to euthyroid dogs with levothyroxine, for either 8 weeks (group 1) or 16 weeks (group 2). Serum concentrations of total thyroxine (T4), free thyroxine (fT4) by equilibrium dialysis, thyrotropin (TSH), and 3,5,3'-triiodothyronine (T3) were measured every 4 weeks during supplementation and for 16 weeks after levothyroxine was discontinued. Results: Mean serum T4 and fT4 were significantly higher and TSH was lower in all dogs during levothyroxine administration compared to baseline. Mean serum concentrations of T4 and fT4 in both groups and TSH in group 1, beginning 1 week after levothyroxine was discontinued, were significantly different compared to values during levothyroxine administration but not compared to baseline values. Conclusions and Clinical Importance: Suppression of the HPTA occurred during levothyroxine supplementation and mean serum T4, fT4 and TSH concentrations were not significantly different compared to baseline 1 week after discontinuation in both groups. Assessing thyroid function tests 1 week after cessation of levothyroxine will likely provide an accurate assessment of thyroid function in euthyroid dogs. Master of Science

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. Master of Science

Background: The liver biopsy technique in dogs that consistently provides samples adequate for accurate histopathologic interpretation and the variability of histopathology among lobes is unknown. Hypothesis: Liver biopsy specimens obtained via punch, cup biopsy, and 14 gauge needle biopsy would result in similar histopathologic diagnoses to those found on deeply sectioned samples of liver obtained at necropsy and that discordant results would not differ between lobes. Animals: Seventy dogs undergoing necropsy. Methods: Liver specimens were obtained from the left lateral liver lobe with an 8 mm punch, a cup, and a 14 gauge needle. Two larger tissue samples were then collected near the center of the left lateral lobe and used as a histologic standard for comparison. Samples were also obtained from all remaining lobes. Histopathologic features and numbers of portal triads in each sample were compared. Results: The mean number of portal triads were 2.9 in needle biopsies, 3.4 in cup biopsies, 12 in punch biopsies, and 30.7 in the necropsy samples. Sixty-six percent of needle biopsies, 60% of laparoscopic cup samples, and 69% of punch samples were in agreement with the necropsy samples, differences that were not significantly different. The corresponding kappa coefficient were 0.59 for needle biopsies, 0.52 for cup biopsies, and 0.62 for punch biopsies. Discordant results did not differ between the liver lobes. Conclusions and Clinical Relevance: A single biopsy using any of the tested techniques is insufficient for reliable diagnosis of liver disease in the dog. Multiple biopsies from 2 lobes is recommended. Master of Science

Background: Hyperthyroidism has substantial effects on the circulatory system. The cardiac biomarkers NT-proBNP and troponin I (cTNI) have proven useful in identifying cats with myocardial disease but have not been as extensively investigated in hyperthyroidism. Hypothesis: Plasma NT-proBNP and cTNI concentrations are higher in cats with primary cardiac disease than in cats with hyperthyroidism and higher in cats with hyperthyroidism than in healthy control cats. Animals: Twenty-three hyperthyroid cats, 19 cats with HCM without congestive heart failure, and 19 euthyroid, normotensive healthy cats eight years of age or older. Fourteen of the hyperthyroid cats were re-evaluated three months after administration of 131I. Methods: A complete history, physical examination, complete blood count, serum biochemistries, urinalysis, blood pressure measurement, serum T4 concentration, plasma concentrations of NT-proBNP and cTNI, and echocardiogram was prospectively obtained from each cat. Results: Hyperthyroid and HCM cats had plasma NT-proBNP and cTNI concentrations that were significantly greater than healthy older cats, but there was no significant difference between hyperthyroid and HCM cats with respect to concentration of either biomarker. In hyperthyroid cats that were re-evaluated three months after 131I treatment, plasma NT-proBNP and cTNI concentrations as well as ventricular wall thickness decreased. Conclusions and Clinical Relevance: Although there may be a role for NT-proBNP in monitoring the cardiac response to treatment of hyperthyroidism, neither NT-proBNP nor cTNI can be used to distinguish hyperthyroid cats from cats with HCM. Therefore, the thyroid status of older cats should be ascertained prior to interpreting results of cardiac biomarker testing. Master of Science

Objectives: To determine the effects of prednisone and prednisone plus ultralow-dose aspirin on coagulation in healthy dogs, and to determine intra-individual variation in thromboelastography (TEG). Animals: 14 healthy experimental dogs and 10 healthy client-owned dogs Procedures: Prospective, randomized, blinded study. TEG was performed twice three days apart on each experimental dog prior to treatment and intra-individual variation was calculated. Dogs were given prednisone (2 mg/kg/day) plus aspirin (0.5 mg/kg/day) or prednisone (2 mg/kg/day) plus placebo for 14 days, after which TEG and other baseline tests were repeated. Changes from baseline between and within each group were compared using t-tests or Wilcoxon 2 sample tests. Client owned dogs had TEG performed twice three days apart to determine intra-individual variation. Results: Intra-individual variation in TEG parameters were

Objective: To determine the efficacy and safety of iopanoic acid for the treatment of experimentally-induced hyperthyroidism in cats. Animals: 15 healthy adult domestic short hair cats Procedures: Hyperthyroidism was induced by daily subcutaneous administration of levothyroxine for 42 days. On day 28, cats were randomized to a control group receiving a placebo PO every 12 hours, a low dose group receiving 50 mg iopanoic acid PO every 12 hours, and a high dose group receiving 100 mg iopanoic acid PO every 12 hours. Cats were treated for 14 days. Weight and heart rates were obtained on days -8, 0, 28, 35, and 42. Blood was collected for CBC and biochemical analysis and for T4, T3, and rT3 measurement on days -8, 28, 35, and 42. Results: Two cats were removed prior to day 28 due to prolonged anorexia and another on day 36 because of heart failure. The low dose and high dose groups had significantly lower T3 concentrations on days 35 and 42 compared to the control group and to their own T3 concentrations on day 28. The T3 concentrations in cats administered iopanoic acid were not different from those obtained prior to induction of hyperthyroidism. Body weight and food consumption were not altered by iopanoic acid treatment, while heart rate was decreased in the low dose group on day 35 when compared to day 28. Conclusions and clinical relevance: Iopanoic acid was effective in decreasing T3 concentrations, but its effect on clinical signs of hyperthyroidism was less apparent. Studies evaluating the long-term efficacy in cats with naturally-occurring hyperthyroidism are warranted. Master of Science

Background: Many non-thyroidal factors affect thyroid function tests. Anesthesia and surgery have been documented to affect thyroid function tests in humans but have not been extensively studied in dogs. Hypothesis: Anesthesia alone and anesthesia combined with surgery will affect thyroid function tests in dogs. Animals: 15 euthyroid mongrel dogs. Methods: Dogs were assigned to one of three groups: control, general anesthesia, and general anesthesia plus abdominal exploratory surgery. Blood samples were collected from each dog immediately prior to pre-medication, 20 minutes after pre-medication, 55 minutes after anesthesia induction, once daily for an additional 6 days, and 14 days post-procedures. Sampling was performed at identical times in the control group. Thyroxine (T4), free T4 (fT4) by equilibrium dialysis, triiodothyronine (T3), reverse T3 (rT3) and thyroid-stimulating hormone (TSH) concentrations were measured in all samples. Results: Results of all thyroid function tests were not significantly different between control and anesthesia groups. Serum T3 for the surgery group decreased significantly from baseline compared to the control and anesthesia groups at multiple times. Serum T4 and rT3 for the surgery group increased significantly from baseline compared to the control and anesthesia groups at multiple times. Serum fT4 for the surgery group increased significantly from baseline compared to the control and anesthesia groups at 48 hours only. Conclusions and Clinical Importance: Surgery has a significant effect on thyroid function tests, while the anesthetic protocol used in this study does not. Because serum T4 and fT4 concentrations increased rather than decreased, evaluating these hormones following surgery is unlikely to lead to a misdiagnosis of hypothyroidism in euthyroid dogs. Master of Science

The objective of these studies was to contribute to the understanding and assessment of thyroid function in horses. The first study evaluated methods of assessing thyroid function in horses, including validation of an enzyme immunoassay (EIA) for measuring equine thyroid hormones and development and assessment of a thyrotropin releasing hormone (TRH) response test. Our data indicated that EIA is an acceptable method for the measurement of total (T) and free (F) thyroxine (T4) and triiodothyronine (T3) in equine plasma. Its measurements are not equivalent to values obtained by radioimmunoassay (RIA), but they can be calibrated to predict corresponding RIA values. A protocol was developed for TRH response tests involving administration of 1 mg TRH intravenously, with blood sample collection immediately before, 2.5, 5.0, and 24 h after administration. Analysis of plasma TT4, FT4, TT3, and FT3 revealed that the magnitude of hormone response was best approximated by the area under the curve of hormone plotted against time and by the absolute change in thyroid hormone concentration. Baseline concentrations, peak concentrations, and percent of baseline values were not as well able to predict the magnitude of hormone response. The second study assessed the effects of exercise and feed composition on thyroid status. Thirteen mature Arabian geldings, adapted to either a high sugar and starch (SS) or high fat and fiber (FF) feed, underwent 15 wk of exercise training followed by a treadmill exercise test. The TRH response tests performed before training, after training, and the morning after the exercise test revealed that the exercise test decreased the TT4 and FT4 response, whereas feeding of high levels of sugars and starches increased the response of TT3 and FT3. During the first four weeks of training, increased TT4 and FT4 concentrations occurred simultaneously with increased nonesterified fatty acid concentrations, decreased triglyceride concentrations, and increased insulin sensitivity. The increase in TT4 and FT4 may have provided the cellular signaling necessary for increased lipolysis and insulin sensitivity. These metabolic changes facilitate the increases in lipid and carbohydrate metabolism that are needed to fulfill the additional energy requirements of regular exercise. The third study assessed thyroid status in ponies with different laminitic histories. Total T4, FT4, TT3, and FT3 were measured during March and May 2004 in 126 ponies that were categorized as either previously laminitic (PL; n = 54) or never laminitic (NL; n = 72) and evaluated for current laminitis in May (CL; n = 13). Decreased concentrations of TT4 and FT4 were found in PL ponies when compared to NL ponies in March (P = 0.018, 0.020) and May (P = 0.018, 0.001). However, TT4 and FT4 concentrations in CL ponies were not different than concentrations in NL ponies in May (P = 0.82, 0.72), and when retrospectively separated out in March, were not different than NL ponies (P = 0.90, 0.84). Therefore, basal thyroid hormone concentrations are not useful as a predictor or hormonal characteristic of pasture-associated laminitis. The decreased TT4 and FT4 in PL ponies may be an indication of a response or compensation to laminitis and may facilitate the metabolic changes necessary to cope with the disease. Master of Science

Recent work in humans with protein losing nephropathies has revealed increased urine concentrations of sulfated glycosaminoglycans (GAGs). Differences exist between normal patients, those with glomerulonephritis (GN), and those with amyloidosis thus potentially allowing differentiation without a renal biopsy. Aims of this study were to validate a simple spectrophotometric assay used to measure canine urinary GAGs, establish a normal reference range, and determine optimal storage conditions. Urine GAG concentrations were measured in a limited number of dogs with glomerulonephritis or amyloidosis. Fourteen healthy dogs were placed in metabolic cages and all urine was collected for 24 hours. Serum and urine creatinine concentrations were measured at the beginning and end of the collection period. Urine collected at the beginning of the 24-hr period was centrifuged and the supernatant used to measure a spot GAG concentration and a spot glycosaminoglycan to creatinine ratio (GCR). A well mixed aliquot of the 24-hr sample was centrifuged, the supernatant used to measure the 24-hr total GAG, and stored at 4°C and -20°C for 1, 7, and 30 days. All dogs were used to determine effects of time and temperature (n=14), however, only dogs with an endogenous creatinine clearance > 2 ml/min/kg (n=10) were used to determine normal values. A standard absorption curve using a 1,9-dimethlymethylene blue dye and dilutions of chondroiton-4-sulfate was developed to estimate total GAG concentration. Repeated measures analysis of variance was used to test for effects of storage temperature and time on stability of urinary GAG. A p-value of < 0.05 was considered significant. Relationships between spot urinary GAG concentration, spot urinary GAG to creatinine ratio (GCR) and 24-hr total GAG excretion were estimated using simple linear regression. Single urine samples were collected by cystocentesis from dogs with GN or renal amyloidosis. The diagnosis was confirmed by clinical evaluation or by histologic analysis. Urine protein, creatinine and GAG concentrations were measured. There were no time or temperature effects on urine GAG concentrations for up to 1 day at 4°C and 30 days at -20°C. Mean 24-hr total GAG excretion ± standard deviation was 1.586 ± 0.461 mg/kg of body weight. Mean spot GAG concentration and spot GCR were 5.007 ± 1.588 mg/dl and 0.023 ± 0.01 respectively. Neither spot GAG concentration (R2=0.4216) nor GCR (R2= 0.0839) were adequate predictors of 24-hr total GAG. The GCR's from dogs with renal disease were not different from normal dogs. This study established normal total urinary GAG values in dogs. Contrary to findings in humans, there was no correlation between 24-hr total sulfated GAG and spot GCR in dogs, limiting clinical utility of this test. Further work is needed to determine if either total sulfated GAG or the spot GCR can be used to differentiate causes of protein-losing nephropathies in dogs. Master of Science

Objective: To evaluate pressor sensitivity to catecholamines in dogs after induction of iatrogenic hyperadrenocorticism (I-HAC) by serial arterial blood pressure measurements during infusions of increasing dose rates of norepinephrine. Animals: Eight dogs with I-HAC induced by administration of oral hydrocortisone at a mean dose of 3.3 mg/kg PO TID for 42-49 days and 8 control dogs which received empty gelatin capsules PO TID for 42-49 days. Procedure: Systolic, diastolic, mean blood pressure and heart rate measurements were recorded after sequential administration of increasing dose rates of norepinephrine (0.1, 0.125, 0.2, 0.3, 0.4, 0.6 and 0.8 mg/kg/min) for 10 minutes. The changes in systolic, diastolic, mean blood pressure and heart rate were compared between control dogs and dogs with I-HAC. Results: Dogs in the I-HAC group had a more pronounced pressor response to norepinephrine infusions than control dogs. The infusions were not completed in 7 of the 8 dogs in the I-HAC group versus 3 dogs in the control group due to severe elevations in systolic blood pressure. The mean change in systolic blood pressure was consistently higher in dogs in the I-HAC group. The difference was statistically significant at the 0.2 mg/kg/min norepinephrine dose rate. The mean change in heart rate was consistently lower in the I-HAC group, a difference that was significant at the 0.2 mg/kg/min norepinephrine dose rate. Conclusions and clinical relevance: Increased pressor sensitivity or decreased baroreceptor response to norepinephrine was seen in dogs with I-HAC suggesting that this mechanism is involved in the development of hypertension in canine hyperadrenocorticism. Master of Science

Tricyclic antidepressants have been shown to alter thyroid function in man and laboratory animals, but have not been evaluated in the dog. The effect of administration of clomipramine on canine thyroid function was studied in a prospective protocol in which 14 mature, healthy dogs were administered clomipramine (3 mg/kg PO q12h) for 112 days. Thyroid-stimulating hormone (TSH), total thyroxine (T4), total 3,5,3' triiodothyronine (T3), free thyroxine (fT4), and 3,3',5' triiodothyronine (reverse T3; rT3) concentrations were measured on selected days. Thyrotropin-releasing hormone (TRH) response tests were performed concurrently. Repeated measures analysis of variance was applied to test for effects of day of treatment; when significance (p < 0.05) was noted, it was further investigated using orthogonal polynomial trends. Significant decreases were found in serum T4 (26 ± 1.2 to 17 ± 0.5 nmol/L, p < 0.001), fT4, (29 ± 2.4 to 19 ± 1.3 pmol/L, p < 0.0002), and rT3 (1.2 ± 0.1 to 0.83 ± 0.08 nmol/L, p < 0.0001) concentrations. The effect of time on serum T3 concentration was also significant (p < 0.0001), but no consistent trend could be identified. No significant effect of time was noted in either pre- or post-TRH TSH concentrations. The results of this study indicate that significant and substantial decreases in T4 (35%), fT4 (38%), and rT3 can occur during clomipramine administration. Long-term administration of clomipramine may result in a misdiagnosis of hypothyroidism if a dog is tested while taking this medication and, since decreased serum fT4 occurs, hypothyroidism may result. Master of Science

This study monitored the storage lesion of 15 units of canine platelet concentrates harvested by differential centrifugation. Canine platelet concentrates were stored at 20-24°C in a platelet rotator for a total of 9 days; the storage lesion of three second generation platelet storage containers was compared. The battery of in vitro tests used to monitor the storage lesion were selected from previous studies performed with human platelet concentrates separated by differential centrifugation. Based on these tests, canine platelet concentrates exhibited a storage lesion similar to human platelet concentrates. Metabolic analytes demonstrated decreasing pH, carbon dioxide, bicarbonate and glucose concentrations concurrent with increasing oxygen and lactate dehydrogenase activity over the 9-day period. Platelet structural changes were monitored by mean platelet volume, which began to increase on Day-5. Platelet function appeared to be compromised, as indicated by aggregation studies using collagen and adenosine diphosphate as agonists. Product sterility was maintained. There was no consensus of data supporting superior performance of one platelet storage container. This study indicates that canine platelet concentrates may be harvested by differential centrifugation of whole blood. In vitro studies utilizing three second-generation platelet storage bags support a previous study and concurs that canine platelet concentrates stored at 20-24°C using continuous agitation are viable for at least 5 days. Master of Science

Cerebrospinal fluid (CSF) analysis is a standard part of a diagnostic evaluation. Commonly evaluated components include the cell count, protein concentration, glucose, and cytology. CSF analysis can be diagnostic in some diseases such as fungal infections and CNS lymphoma. Often, CSF analysis is not specific, but more information can be obtained. Matrix Metalloproteinases (MMPs) are enzymes that have been found in human CSF. They are calcium and zinc dependent endoproteinases with overlapping substrates. They hydrolyze at least one component of tissue extracellular matrix (ECM), such as collagen or elastin. They are important in normal physiologic processes such as angiogenesis, reproduction and wound healing. One class of MMPs, the gelatinases, degrade gelatins and type IV collagen include MMP 2 and MMP 9. MMPs are important in many pathological processes that involve unregulated matrix destruction such as arthritis, neoplasia and CNS diseases. MMP2 is known to be constituitively produced in CSF while MMP 9 is present only in certain pathologic conditions such as multiple sclerosis, neoplasia and inflammatory diseases. We hypothesize that MMP2 is present in normal canine CSF while MMP 9 is absent. Cerebrospinal fluid samples were taken from 23 normal dogs that were being used for other research purposes. Each CSF sample was evaluated immediately for red blood cells (RBCs), white blood cells (WBCs), protein, and glucose, and then stored at -70°C. Cytological examination was also performed. CSF samples were considered normal if the protein was less than 25 mg/dl, WBCs were less than 6 µl, and RBCs were less than 25 µl. Each dog was euthanized and the brains processed for routine histopathology. MMP analysis was done using gelatin zymography and an enzyme linked immunosorbent assay (ELISA). Bands of enzyme activity were visible following staining due to enzyme degradation of the gelatin. A commercially available polyclonal sandwich ELISA was used to identify the pro form of MMP2. The mean WBC count for the CSF samples was 0.96 WBC/ml with a range of 0-3 WBC/ml. The mean protein was 12 mg/dl, with a range of 8-17 mg/dl. The mean RBC count was 3.65 RBC/ml with a range of 0-21 RBC/ml. All normal samples of CSF contained a band of clearing that corresponded to the human commercial standard of proMMP2. No other major bands of clearing were noted on normal samples. The commercial human standards also contained ProMMP2. Other bands were present, but were faint and variable. Using a polyclonal antibody based sandwich ELISA, with samples run in triplicate, the mean pro MMP 2 levels were determined to be 5.61 ng/ml with a range of 3.36 - 10.83 ng/ml. We conclude that normal CSF values are narrower than what has been previously reported for protein concentration and WBC count. Also, the pro form of MMP 2 is present in normal canine CSF based on results of gelatin zymography and ELISA. Master of Science