Search Results

You are looking at 11 - 20 of 36 items for

  • Author or Editor: Mark A. Mitchell x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To evaluate the effects of IM administration of recombinant human thyroid-stimulating hormone (rhTSH) on plasma total thyroxine (T4) concentrations in euthyroid ferrets.

Design—Evaluation study.

Animals—25 healthy neutered ferrets (14 female and 11 male) of various ages from 2 populations (laboratory ferrets from Georgia and pet ferrets from Pennsylvania).

Procedures—Each ferret underwent a physical examination and standard hematologic testing to ensure it was healthy and had clinically normal thyroid function. Once determined to be euthyroid, ferrets received a single IM injection of 100 μg of rhTSH. Blood samples were collected into plasma-separator tubes immediately before the rhTSH injection (time 0) and 4 hours after injection to measure T4 concentrations.

Results—Males did not differ from females in regard to prestimulation or poststimulation plasma T4 concentrations; however, prestimulation and poststimulation T4 concentrations were significantly different between the 2 groups of ferrets. A significant difference was also identified between prestimulation T4 concentration (mean ± SD, 21.3 ± 6.1 nmol/L) and poststimulation T4 concentration (29.9 ± 8.2 nmol/L). All 25 ferrets had high poststimulation T4 concentrations (median difference, 7. 5 nmol/L; 10% to 90% interval, 3.26 to 17.70 nmol/L [0.25 to 1.38 μg/dL]; range, 2.50 to 20.70 nmol/L [0.19 to 1.61 μg/dL]); this represented a median increase in T4 concentration of 35% (10% to 90% interval, 18% to 81%; range, 8% to 126%).

Conclusions and Clinical Relevance—Results suggested that rhTSH can be used for thyrotropin stimulation testing in ferrets when administered IM. According to the findings, a euthyroid ferret should have an increase of approximately 30% in plasma T4 concentration 4 hours after rhTSH injection.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the effects of administration of recombinant human (rh) thyroid-stimulating hormone (TSH) for evaluation of thyroid function in euthyroid guinea pigs (Cavia porcellus).

Design—Prospective, experimental study.

Animals—10 healthy, sexually intact, pet guinea pigs (approx 1 year of age).

Procedures—Guinea pigs were given rhTSH (100 μg, IM); plasma thyroxine concentrations were determined prior to and 3 and 4 hours after rhTSH injection. The animals were housed in 2 groups on the basis of sex and fed different commercial maintenance diets according to their husbandry.

Results—There was no significant difference in thyroxine concentrations between males and females before or after rhTSH injection. There was also no difference between thyroxine concentrations at 3 versus 4 hours after rhTSH injection. There was a significant difference between thyroxine concentrations before (median, 9.05 nmol/L [0.70 μg/dL]; 10% to 90% range, 7.39 to 16.99 nmol/L [0.57 to 1.32 μg/dL]) and after (mean ± SD, 23.95 ± 4.2 nmol/L) rhTSH injection. Euthyroid guinea pigs had plasma thyroxine concentrations of at least 7.30 nmol/L (0.57 μg/dL) and an increase of at least 2.6 times prestimulation thyroxine concentrations at 3 or 4 hours after stimulation.

Conclusions and Clinical Relevance—The results suggested that rhTSH administered IM can be used for the TSH stimulation testing in guinea pigs. We suggest thyroxine concentration in a euthyroid guinea pig should at least double 3 to 4 hours after rhTSH injection.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare use of lidocaine-bupivacaine–infused absorbable gelatin hemostatic sponges versus lidocaine-bupivacaine retrobulbar injections for postoperative analgesia in dogs following eye enucleation.

Design—Randomized case-control study.

Animals—19 dogs that underwent eye enucleation.

Procedures—19 client-owned dogs admitted to a referral hospital for routine eye enucleation were enrolled with owner consent and randomly assigned to receive an orbital absorbable gelatin hemostatic sponge infused with lidocaine and bupivacaine after globe removal (n = 8) or retrobulbar injection of lidocaine and bupivacaine before globe removal (11). Baseline pain scores were recorded on the basis of an ordinal pain scale. Anesthetic premedication consisted of hydromorphone, midazolam, and glycopyrrolate. Propofol was used for anesthetic induction and isoflurane for maintenance. A transpalpebral eye enucleation was performed by a board-certified ophthalmologist. Pain scores and heart rate were again recorded 15 and 30 minutes and 1, 2, 4, 6, 8, and 24 hours after extubation by trained observers masked to treatment groups. Dogs were given hydromorphone as rescue analgesia if the total pain score was ≥ 9 of 18 or any categorical pain score was ≥ 3 (on a scale from 0 to 3 or 0 to 4).

Results—There were significant differences over time for comfort level, response to touch, behavior, heart rate, and total pain score; however, there was no difference between treatment groups. One dog in the absorbable gelatin hemostatic sponge group required rescue hydromorphone 4 hours after surgery.

Conclusions and Clinical Relevance—The absorbable gelatin hemostatic sponge proved to be as effective in providing local analgesia for eye enucleation in dogs as the retrobulbar injections.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate histologic reactions to 8 suture materials and cyanoacrylate tissue adhesive (CTA) in the musculature and skin of ball pythons.

Animals—30 hatchling ball pythons.

Procedures—In each snake, ten 1-cm skin incisions were made (day 0). At 8 sites, a suture of 1 of 8 materials was placed in the epaxial musculature, and the incision was closed with the same material. One incision was closed by use of CTA. No suture material was placed in the tenth incision, which was allowed to heal by second intention (negative control). Snakes (n = 5/group) were euthanized for harvest of treatment-site tissues at days 3, 7, 14, 30, 60, and 90. Skin and muscle sections were examined microscopically and assigned a subjective score (0 to 4) for each of the following: overall severity of inflammation, fibrosis, number of macrophages, number of granulocytes, number of perivascular lymphocytes, and degree of suture fragmentation.

Results—Subjective score analysis revealed that CTA did not cause a significant inflammatory response, compared with the negative control. All suture materials caused significantly more inflammation over all time points; for all suture materials, inflammatory response scores were significantly higher than values for the negative control 90 days after implantation. No sutures were completely absorbed by the end of the study period, and several sutures appeared to be in the process of extrusion.

Conclusions and Clinical Relevance—In snakes, CTA can be used to close small superficial incisions or lacerations with minimal inflammatory response, and sutures may undergo extrusion from tissues prior to complete absorption.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the righting reflex after topical application of a sevoflurane jelly in cane toads (Bufo marinus).

Animals—8 cane toads.

Procedures—Toads were 6 to 8 months of age and weighed (mean ± SD) 142.0 ± 25.2 g. Sevoflurane jelly was applied to the dorsum of each toad at a dose of 25 μL/g in trial 1 and 37.5 μL/g in trial 2. Toads were placed in dorsal recumbency every 30 seconds until loss of the righting reflex. Jelly was then removed by rinsing the toads with tap water. Toads were then left undisturbed in dorsal recumbency until return of the righting reflex. Chamber sevoflurane concentration was measured to determine vaporization.

Results—6 of 8 toads in trial 1 and 8 of 8 toads in trial 2 lost the righting reflex. Mean ± SD time to loss of the reflex was 8.2 ± 1.3 minutes for trial 1 and 8.3 ± 0.9 minutes for trial 2; this difference was not significant. Mean ± SD time to return of the reflex was 25.6 ± 26.2 minutes for trial 1 and 84.4 ± 47.2 minutes for trial 2; this difference was significant. Chamber sevoflurane concentration did not change significantly, compared with baseline (time 0) concentration, at any time in trial 1; however, there was a significant change in chamber sevoflurane concentration from baseline (time 0) concentration in trial 2. Chamber sevoflurane concentrations were not significantly different between trial 1 and trial 2 at any time. Mean ± SD chamber sevoflurane concentration was 0.46 ± 0.2% for trial 1 and 0.57 ± 0.28% for trial 2.

Conclusions and Clinical Relevance—Sevoflurane jelly applied topically at a dose of 37.5 μL/g induced a more reliable loss of righting reflex and longer recovery time than when applied at a dose of 25 μL/g in cane toads.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To characterize long-term elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CI-CSH) beads in vitro by comparing 2 distinct sample collection methods designed to mimic 2 in vivo environments.

SAMPLES 162 CI-CSH beads containing 4.6 mg of carboplatin (2.4 mg of platinum/bead).

PROCEDURES For method 1, which mimicked an in vivo environment with rapid and complete fluid exchange, each of 3 plastic 10-mL conical tubes contained 3 CI-CSH beads and 5 mL of PBS solution. Eluent samples were obtained by evacuation of all fluid at 1, 2, 3, 6, 9, and 12 hours and 1, 2, 3, 6, 9, 12, 15, 18, 22, 26, and 30 days. Five milliliters of fresh PBS solution was then added to each tube. For method 2, which mimicked an in vivo environment with no fluid exchange, each of 51 tubes (ie, 3 tubes/17 sample collection times) contained 3 CI-CSH beads and 5 mL of PBS solution. Eluent samples were obtained from the assigned tubes for each time point. All samples were analyzed for platinum content by inductively coupled plasma–mass spectrometry.

RESULTS Platinum was released from CI-CSH beads for 22 to 30 days. Significant differences were found in platinum concentration and percentage of platinum eluted from CI-CSH beads over time for each method. Platinum concentrations and elution percentages in method 2 samples were significantly higher than those of method 1 samples, except for the first hour measurements.

CONCLUSIONS AND CLINICAL RELEVANCE Sample collection methods 1 and 2 may provide estimates of the minimum and maximum platinum release, respectively, from CI-CSH beads in vivo.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To characterize the elution of platinum from carboplatin-impregnated calcium sulfate hemihydrate (CSH) beads in vitro.

SAMPLE 60 carboplatin-impregnated CSH beads and 9 CSH beads without added carboplatin (controls).

PROCEDURES Carboplatin-impregnated CSH beads (each containing 4.6 mg of carboplatin [2.4 mg of platinum]) were placed into separate 10-mL plastic tubes containing 5 mL of PBSS in groups of 1, 3, 6, or 10; 3 control beads were placed into a single tube of PBSS at the same volume. Experiments were conducted in triplicate at 37°C and a pH of 7.4 with constant agitation. Eluent samples were collected at 1, 2, 3, 6, 12, 24, and 72 hours. Samples were analyzed for platinum content by inductively coupled plasma–mass spectrometry.

RESULTS The mean concentration of platinum released per carboplatin-impregnated bead over 72 hours was 445.3 mg/L. Cumulative concentrations of platinum eluted increased as the number of beads per tube increased. There was a significant difference in platinum concentrations over time, with values increasing over the first 12 hours and then declining for all tubes. There was also a significant difference in percentage of total incorporated platinum released into tubes with different numbers of beads: the percentage of eluted platinum was higher in tubes containing 1 or 3 beads than in those containing 6 or 10 beads.

CONCLUSIONS AND CLINICAL RELEVANCE Carboplatin-impregnated CSH beads eluted platinum over 72 hours. Further studies are needed to determine whether implantation of carboplatin-impregnated CSH beads results in detectable levels of platinum systemically and whether the platinum concentrations eluted locally are toxic to tumor cells.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether an association exists between oral bacterial contamination of bronchoalveolar lavage fluid (BALF) and positive PCR assay results for the detection of Mycoplasma spp in BALF samples of dogs with lower respiratory tract (LRT; portion from the trachea to the lungs) disease.

Design—Retrospective case series.

Animals—121 dogs with LRT disease.

Procedures—Medical records from January 2005 to April 2012 were reviewed. Dogs with LRT disease that had BALF samples evaluated by use of Mycoplasma-specific PCR assay, bacterial culture, and cytologic examination were included. Information on signalment, final diagnoses, and BALF testing results was extracted.

Results—83 (68.6%) dogs had BALF samples with negative PCR assay results for Mycoplasma spp, and 38 (31.4%) had positive results. The BALF samples with cytologic evidence of oral bacterial contamination were 5.1 times as likely to have positive Mycoplasma-specific PCR assay results as were noncontaminated samples. Compared with hound or herding dogs, other breeds were 13.6 times as likely to have positive PCR assay results. Dogs with bronchitis were less likely than dogs with other LRT diseases to have positive Mycoplasma-specific PCR assay results. No significant association was found between Mycoplasma-specific PCR assay results and bacterial culture results.

Conclusions and Clinical Relevance—In dogs with LRT disease, Mycoplasma-specific PCR assay results for BALF samples should be interpreted in terms of possible oral bacterial contamination. Mycoplasma-specific PCR assay of BALF samples from herding dogs, hound dogs, and dogs with bronchitis may be less rewarding than for other dogs with LRT disease.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To measure plasma and tissue activities of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase (AST), creatine kinase, and γ-glutamyltransferase in 2 snake species.

ANIMALS

6 banded water snakes (Nerodia fasciata) and 6 diamondback water snakes (Nerodia rhombifer).

PROCEDURES

Blood was collected via the ventral tail vein to measure plasma enzyme activities. Animals were then euthanized, and samples of 9 tissues were collected from each snake: skeletal muscle, cardiac muscle, liver, spleen, lung, kidney, testicle, pancreas, and gallbladder. Tissues were frozen for 30 days, then homogenized and processed. Supernatants were collected and analyzed within 24 hours of processing. A linear mixed model was used to determine differences in enzyme activity between tissues and species and assess interactions between tissues and species.

RESULTS

Activities of all enzymes were found to differ significantly among tissues. There were also significant differences between species for all enzyme activities, except AST activity. The kidney had the highest alanine aminotransferase and γ-glutamyltransferase activities. Alkaline phosphatase activity was significantly highest in liver and kidney tissues than in other tissue. Creatine kinase activity was highest in skeletal muscle, followed by cardiac muscle and kidney. AST activity was present in all tissues evaluated, but was highest in liver, kidney, and cardiac muscle in both species.

CLINICAL RELEVANCE

Results reinforced the importance of characterizing the origin of tissue enzymes in reptiles to improve our understanding of biochemistry results and highlighted the differences that can exist in tissue enzyme activities between closely related species.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate agreement of blood glucose concentrations measured in juvenile white-tailed deer (Odocoileus virginianus) by use of 2 point-of-care (POC) blood glucose meters and 1 portable chemistry analyzer with values obtained in serum by use of a standard laboratory chemistry analyzer, and to evaluate agreement between results obtained with the 2 POC meters.

Design—Prospective evaluation study.

Sample—14 venous blood samples from 14 healthy white-tailed deer fawns.

Procedures—Blood glucose concentration was measured with each of 2 POC meters. The remainder of the sample was divided into 2 tubes (1 that contained lithium heparin and 1 with no anticoagulant). Glucose concentration in anticoagulated whole blood was measured with the portable analyzer. Serum was collected from the remaining sample for measurement of glucose concentrations with the laboratory analyzer. Bland-Altman plots were used to assess agreement.

Results—Agreement between POC blood glucose meters and the laboratory analyzer was poor; mean values for bias were 2.9 mg/dL (95% limits of agreement [LOA], −70.2 to 76.0 mg/dL) and −30.8 mg/dL (95% LOA, −111.6 to 49.9 mg/dL), respectively. Agreement between the 2 POC meters was also poor (bias, 31.0 mg/dL; 95% LOA, −47.2 to 109.2 mg/dL). Agreement between the portable analyzer and the laboratory analyzer was good (bias, −1.6 mg/dL; 95% LOA, −15.3 to 12.1 mg/dL).

Conclusions and Clinical Relevance—Results suggested that the POC blood glucose meters used in this study are not appropriate for measurement of blood glucose concentrations in juvenile white-tailed deer.

Restricted access
in Journal of the American Veterinary Medical Association