Browsing by Author "Grant, David C."
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- Assessment of Bacteriuria and Surgical Site Infections in Dogs with Cranial Cruciate Ligament DiseaseGarcia, Cheslymar (Virginia Tech, 2019-06-21)Objective: The aims of this prospective clinical cohort study were to determine the prevalence of asymptomatic bacteriuria in dogs with cranial cruciate ligament disease and to determine which clinical parameters and clinicopathologic data are associated with asymptomatic bacteriuria. Another aim was to determine the incidence of surgical site infections in dogs with and without asymptomatic bacteriuria. Results: In 156 dogs with cruciate ligament disease, the prevalence of asymptomatic bacteriuria was 7.1%. Furthermore, the prevalence was 12.4% in female dogs and 0% in male dogs. The most common bacterial isolate was Escherichia coli. Patient sex, urine white blood cells/ high-powered field, and microscopic bacteriuria were significantly different between dogs with and without asymptomatic bacteriuria. Only 60% of dogs with microscopic bacteriuria had growth on urine aerobic culture. No significant difference was found in age, body weight, body condition score, duration of lameness, limb affected, or other urinalysis values between dogs with and without asymptomatic bacteriuria. Of the dogs that had 8-week repeat cultures, 2/3 dogs with asymptomatic bacteriuria had negative urine cultures and 3/43 without asymptomatic bacteriuria had positive urine cultures. Of 57 dogs that received surgery and had sufficient follow-up, 15 developed surgical site infection. All surgical site infections occurred in dogs without AB. The incidence of surgical site infection in this population was 26.3% (15/57). Conclusions: Prevalence of asymptomatic bacteriuria in dogs presenting with cranial cruciate ligament disease was similar to previously reported values in male and female dogs. This suggests that dogs with cranial cruciate ligament disease are not more prone to asymptomatic bacteriuria than dogs in previously studied populations. Preliminary data suggests that AB does not predispose dogs to SSI however further research and continued data collection is warranted.
- Development of a Hollow-Core Fiberoptic Microneedle Device for the Treatment of Invasive Bladder CancerHood, Robert L. (Virginia Tech, 2011-08-11)The hydraulic resistance characterization manuscript chronicles the early development of the hollow-core fiberoptic microneedle device (FMD). The study determined that for straight tubing with an inner bore of 150 ?m and a length greater than 50 mm long, Poiseuille's Law was shown to be accurate within 12% of experimental data for the pressure range of 69-517 kPa. Comparison between different needle design geometries indicated that tip diameters <55 ?m cause a significant increase in hydraulic resistance. Tubing length should be kept to a minimum and tip diameter should be kept above this threshold to reduce overall hydraulic resistance. The bladder treatment study describes the fabrication and testing of the FMD for treatment of invasive urothelial cell carcinomas (UCCs). Experiments investigating the fluid dispersal of single-walled carbon nanohorns (SWNHs) in the wall of inflated, healthy ex vivo bladders demonstrated that perfusion of 2 cm° on the bladder wall's surface can be achieved with a 5 minute infusion at 50 ?L/min. Irradiation of the SWNH perfused bladder wall tissue with a free space, 1064 nm laser at an irradiance of 0.95 W/cm° for 40 seconds yielded a 480% temperature increase relative to similar irradiation of a non-infused control. Co-delivery experiments demonstrated both SWNH and light delivery though a single hollow-core fiber to heat the bladder wall 33 °C with an irradiance of 400 W/cm°, demonstrating that the FMD can be used to achieve hyperthermia-based therapeutic effects via interstitial irradiation.
- Diagnostic accuracy of a point-of-care test using voided urine samples for detection of bacteriuria in dogs with signs of lower urinary tract diseaseGrant, David C.; Nappier, Michael T.; Corrigan, Virginia Kiefer (Wiley, 2021-02-01)Background: Bacterial urine culture is recommended in dogs suspected of having urinary tract infection (UTI), but there is expense and delay in obtaining such results. Hypothesis/Objective: To determine the diagnostic performance of a rapid immunoassay (RIA) dipstick for detection of bacteriuria using voided urine from dogs with clinical signs of lower UTI. Animals: Twenty-four client-owned dogs. Methods: Voided urine was collected and the RIA performed within 30 minutes. Urine collected by cystocentesis was submitted for aerobic urine culture. McNemar's test and kappa coefficient were calculated to determine agreement between the 2 tests. Results: Nine of 21 dogs (43%) had UTI verified by aerobic urine culture. There was 1 false-negative and no false-positive RIA results. Sensitivity, specificity, positive predictive value, and negative predictive value of the RIA were 89%, 100%, 100%, and 92%, respectively. Conclusions and Clinical Importance: This RIA is promising for correctly identifying whether or not voided urine samples from dogs with lower urinary tract clinical signs have true bacteriuria in a rapid, inexpensive manner. Additional patients should be enrolled in a similar study to determine if diagnostic performance is robust in a large population.
- The Effects of Prednisone and Prednisone Plus Ultralow-dose Aspirin on Coagulation Parameters in Healthy DogsO'Kell, Allison Louise (Virginia Tech, 2012-01-27)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 <10% for MA (maximum amplitude) and angle. For experimental dogs, MA and fibrinogen significantly increased from baseline whereas Ly30 (percent lysis 30 minutes after MA) and antithrombin activity significantly decreased within each group. For the prednisone plus placebo group, Ly60 (percent lysis 60 minutes after MA) significantly decreased from baseline. For all parameters, there was no difference between groups for change from baseline. Conclusions and Clinical Relevance: Prednisone caused hypercoagulability in healthy dogs evidenced by increased MA and fibrinogen and decreased antithrombin activity. Concurrent use of ultra-low dose aspirin had no effect on measured TEG parameters. Intra-individual variation in some TEG parameters is high and may preclude routine clinical utility.
- Effects of Prednisone or Prednisone with Ultralow-Dose Aspirin on the Gastroduodenal Mucosa of Healthy DogsGraham, Allison Heather (Virginia Tech, 2009-03-20)This study tested the hypothesis that administration of immunosuppressive doses of prednisone in conjunction with ultralow-dose aspirin (0.5 mg/kg/day) would result in gastroduodenal lesion scores similar to those found in dogs administered only immunosuppressive doses of prednisone, but that the gastroduodenal scores from both of these treatment groups would be significantly higher than placebo when administered to healthy dogs for 27 days. Eighteen healthy adult purpose-bred dogs were divided randomly into three groups. Group I received placebo capsules and placebo suspension, Group II received prednisone capsules (mean 2.3 mg/kg, range 2.0-2.4) and placebo suspension, and Group III received prednisone capsules (mean 2.3 mg/kg, range 2.3-2.5) and aspirin suspension (0.5 mg/kg) by mouth once daily for 27 days. Gastroduodenoscopy was performed on days -7 (baseline), 5, 14, and 27 of treatment. Four regions of the stomach (angularis incisura, body, pylorus, and cardia) and the proximal descending duodenum were systematically scored on a scale of 1 (normal) to 11 (perforating ulcer) by an experienced observer who was blinded to the treatment groups and clinical signs of each subject. Dogs were observed every 8 hours for vomiting, diarrhea, and inappetence. Feces were scored on a scale of 1-5 with diarrhea defined as a fecal score <4. Lesion scores for each group, at each location, and total scores, at each time period were evaluated for the effects of time and treatment using a Kruskal-Wallis test. Total dog days of vomiting and dog days of diarrhea in each group were compared using a Wilcoxon rank sums test. Significance was determined at p<0.05. There were no significant differences in median total gastric lesion scores between any of the groups at any time during the study. There was no location effect on regional gastroduodenal lesion scores and there was no significant change in gastroduodenal lesion scores over time in any of the groups during treatment. Significantly more dog-days of diarrhea occurred within the prednisone and aspirin group during the experimental period (Period 2) in comparison to Period 1. However, no significant differences were found between any of the groups for dog-days of vomiting, diarrhea or inappetence at any time in the study.
- Efficacy and safety of iopanoic acid for treatment of experimentally-induced hyperthyroidism in catsGallagher, Alexander Edward (Virginia Tech, 2008-03-07)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.
- Fiber array for optical imaging and therapeutics(United States Patent and Trademark Office, 2019-03-05)The present invention relates to the field of optical imaging and therapeutics. More particularly, embodiments of the present invention provide minimally-invasive Fiberoptic Microneedle Devices (FMDs) for light-based therapeutics, which physically penetrate tissue and deliver light directly into the target area below the skin surface. Embodiments of the invention enable depth-selective and deep photothermal therapeutics and include methods of treating cancer, methods of re-shaping or removing adipose tissue, and methods of delivering drugs or co-delivering drugs and energy to selected tissue.
- Measurement of Pre and Postprandial Urine Calcium to Creatinine Ratio to Identify Calcium Oxalate Urolithiasis in Miniature SchnauzersCarr, 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.
- Measurement of preprandial and postprandial urine calcium to creatinine ratios in male Miniature Schnauzers with and without urolithiasisCarr, Susan V.; Grant, David C.; DeMonaco, Stefanie M.; Shepherd, Megan L. (2020-03)Background We aimed to identify a simple test for excessive calciuresis and predict calcium oxalate (CaOx) disease in Miniature Schnauzers. We investigated the impact of postprandial time on the urine calcium to creatinine ratio (UCa/Cr) in male dogs of this breed, with the goal of improving the utility of the UCa/Cr. Hypotheses (1) Significant differences will exist in preprandial and postprandial UCa/Cr between CaOx urolith-forming and control Schnauzers. (2) The UCa/Cr will increase significantly from the first morning baseline at >= 1 postprandial time point(s) in both control and CaOx urolith-forming dogs. (3) Biochemical abnormalities and other variables may be associated with urolith status. Animals Twenty-four male Miniature Schnauzer dogs, consisting of 9 with (urolith formers) and 15 without (controls) CaOx uroliths. Methods Urine was collected before and 1, 2, 4, and 8 hours after feeding a standardized diet. Receiver operator characteristic curve analysis was performed to identify the UCa/Cr cutoff that most accurately differentiates dogs based on urolith status. Results Urolith formers had significantly higher mean UCa/Cr over the course of 8 hours. The postprandial change in UCa/Cr was not significant at any time point between or within groups. The cutoff UCa/Cr value of 0.06 had a specificity of 93% (95% confidence interval [CI], 80%-100%) and a sensitivity of 56% (95% CI, 21%-86%) for identifying CaOx urolithiasis. Conclusions and Clinical Importance Urolith-forming male Miniature Schnauzers have excessive calciuresis, and the postprandial sampling time up to 8 hours is not critical. This simple urine measurement has potential as a marker of CaOx disease.
- Measurement of urinary glycosaminoglycans in dogsGrant, David C. (Virginia Tech, 2003-06-10)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.
- Natural History of Biliary Sludge in DogsDemonaco, 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.
- Prevalence of Antibodies to Sarcocystis neurona in Cats From Virginia and PennsylvaniaHsu, V.; Grant, David C.; Dubey, Jitender P.; Zajac, Anne M.; Lindsay, David S. (American Society of Parasitology, 2010-08)Sarcocystis neurone, is best known as the causative agent of equine protozoal myeloencephalitis of horses in the Americas. Domestic cats (Felis domesticus) were the first animals described as an intermediate host for S. neurone,. However, S. neurona-associated encephalitis has also been reported in naturally infected cats in the United States. Thus, cats can be implicated in the life cycle of S. neurona as natural intermediate hosts. The present study examined the seroprevalence of IgG antibodies to merozoites of S. neurona in populations of domestic cats from Virginia and Pennsylvania. Overall, sera or plasma from 441 cats (Virginia = 232, Pennsylvania = 209) were tested by an indirect immunofluorescent assay at a 1:50 dilution. Antibodies to S. neurona were found in 32 (7%) of 441 cats. Of these, 22 (9%) of the 232 cats from Virginia and 10 (5%) of the 209 cats from Pennsylvania were seropositive for S. neurona.
- Serological response of cats to experimental besnoitia darlingi and besnoitia neotomofelis infections and prevalence of antibodies to these parasites in cats from Virginia and PennsylvaniaHouk, Alice E.; Rosypal, A. C.; Grant, David C.; Dubey, Jitender P.; Zajac, Anne M.; Yabsley, Michael J.; Lindsay, David S. (American Society of Parasitology, 2011-04)Besnoitia darlingi and Besnoitia neotomofelis are cyst-forming tissue apicomplexan parasites that use domestic cats (Felis domesticus) as definitive hosts and opossums (Didelphis virginiana) and Southern Plains woodrats (Neotoma micropus) as intermediate hosts, respectively. Nothing is known about the prevalence of B. darlingi or B. neotomofelis in cats from the United States. Besnoitia darlingi infections have been reported in naturally infected opossums from many states in the United States, and B. neotomofelis infections have been reported from Southern Plains woodrats from Texas, but naturally infected cats have not been identified. The present study examined the IgG antibody response of cats to experimental infection (B. darlingi n = 1 cat; B. neotomofelis n = 3 cats). Samples from these cats were used to develop an indirect immunofluorescent antibody test (IFAT), which was then used to examine seroprevalence of IgG antibodies to tachyzoites of B. darlingi and B. neotomofelis in a population of domestic cats from Virginia (N = 232 cats) and Pennsylvania (N = 209). The serum from cats inoculated with B. darlingi or B. neotomofelis cross-reacted with each other's tachyzoites. The titers to heterologous tachyzoites were 1 to 3 dilutions lower than to homologous tachyzoites. Sera from B. darlingi- or B. neotomofelis-infected cats did not react with tachyzoites of Toxoplasma gondii or Neospora caninum or merozoites of Sarcocystis neurona using the IFAT. Antibodies to B. darlingi were found in 14% and 2% of cats from Virginia and Pennsylvania, respectively. Antibodies to B. neotomofelis were found in 5% and 4% of cats from Virginia and Pennsylvania, respectively. Nine cats from Virginia and 1 cat from Pennsylvania were positive for both.
- Spontaneous Course of Biliary Sludge Over 12 Months in Dogs with Ultrasonographically Identified Biliary SludgeDeMonaco, Stefanie M.; Grant, David C.; Larson, Martha M.; Panciera, David L.; Leib, Michael S. (American College of Veterinary Internal Medicine, 2016-05)Background: Biliary sludge is associated with gallbladder (GB) dysmotility and mucus hypersecretion suggesting a link between biliary sludge, and the formation of GB mucoceles (GMT). If biliary sludge progresses to GBM, treatment to reduce the production and progression of sludge is warranted. Hypothesis/Objectives: The objective of this study was to determine the course of biliary sludge in dogs. Animals: Seventy-seven healthy, client-owned dogs >= 4 years of age screened for biliary sludge; 45 affected dogs identified. Methods: Prospective, observational design. Serial ultrasound examinations were evaluated at 3, 6, 9, and 12 months to monitor degree of sludge based on proportion of 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, and GB dimensions. Results: Alter 1 year of follow-up, the degree of sludge was mild (34 %), moderate (47% moderate to severe. (13%), severe (30 or absent (3%). There was no significant difference in median degree of sludge over 1 year (P = .36). There were no significant changes in the gravity dependency of sludge over 1 year. A subset of dogs, 24 %, with initial gravity-dependent sludge developed a combination of nondependent and dependent sludge. Dogs had resolved (2%), decreased (19%), static (40%), increased (29%), or recurrent (10 %) sludge at the conclusion of the study. Conclusions and Clinical Importance: Biliary sludge was prevalent, affected dogs remained asymptomatic, and it rarely resolves in healthy dogs over a period of 1 year. Some dogs developed nongravity-dependent sludge within 1 year, which might indicate changes in consistency of sludge.