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  • Author or Editor: Jeffrey A. Roberts x
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Summary

Veterinary diagnostic endocrinology laboratories frequently receive hemolyzed plasma, serum, or blood samples for hormone analyses. However, except for the previously reported harm done by hemolysis to canine insulin, effects of hemolysis on quantification of other clinically important hormones are unknown. Therefore, these studies were designed to evaluate effects of hemolysis on radioimmunoassay of thyroxine, 3,5,3’-triiodothyronine, progesterone, testosterone, estradiol, cortisol, and insulin in equine, bovine, and canine plasma. In the first experiment, hormones were measured in plasma obtained from hemolyzed blood that had been stored for 18 hours. Blood samples were drawn from pregnant cows, male and diestrous female dogs, and male and pregnant female horses. Each sample was divided into 2 equal portions. One portion was ejected 4 times with a syringe through a 20-gauge (dogs, horses) or 22-gauge (cows) hypodermic needle to induce variable degrees of hemolysis. Two subsamples of the blood were taken before the first and after the first, second, and fourth ejections. One sub sample of each pair was stored at 2 to 4 C and the other was stored at 20 to 22 C for 18 to 22 hours before plasma was recovered and stored at —20 C. The second portion of blood from each animal was centrifuged after collection; plasma was recovered and treated similarly as was blood. Concentrations of thyroxine in equine plasma, of 3,5,3’-triiodothyronine, estradiol, and testosterone in equine and canine plasma, and of cortisol in equine plasma were not affected by hemolysis. Storage of bovine blood at either temperature and equine blood at 20 to 22 C caused progesterone concentrations to decrease (P < 0.05); the effect was not enhanced or diminished by hemolysis. Insulin concentration in equine blood decreased (P < 0.05) at both temperatures; this effect was exacerbated by hemolysis. In the second experiment, blood samples from horses and dogs were hemolyzed and plasma was immediately recovered and stored for 18 to 22 hours at 2 to 4 C or 20 to 22 C. Storage of hemolyzed equine plasma did not affect concentrations of progesterone, insulin, or thyroxine at either temperature. Whereas progesterone concentration was not affected in hemolyzed canine plasma, hemolysis decreased (P < 0.05) insulin concentration when plasma was stored at 20 to 22 C. These results emphasize the importance of examining effects of sample collection and handling procedures on hormone stability and the danger of extrapolating results of such studies from one species to another and from one hormone to another.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To develop an endoscopic technique for use in monitoring devlopment of gastric ulcers via a gastric cannula during withholding of feed and administration of a finely ground diet to pigs.

Animals—6 pigs weighing between 60 and 70 kg.

Procedure—A gastric cannula was surgically inserted adjacent to the pars esophagea in each pig. Pigs were fed a finely ground diet for two 7-day periods that were separated by a 48-hour period during which feed was withheld. Endoscopic examination via the gastric cannula was used to monitor development of ulcers in the pars esophageal region of the pigs during the 48-hour period of feed withhold and subsequent 7-day feeding period. An ulcer score was assigned during each endoscopic examination. A final examination was performed during necropsy and compared with results for the final endoscopic examination.

Results—Consumption of a finely ground diet for 7 days resulted in progressive erosive damage to the pars esophageal region of the stomach. Further significant increases in ulcerative damage were detected after 24 and 48 hours of withholding of feed. Final examination during necropsy did not reveal significant differences from results obtained during the final endoscopic examination.

Conclusions and Clinical Relevance—Endoscopic examination via a gastric cannula was an effective means of monitoring ulcer development in the pars esophagea of pigs. Feeding a finely ground diet and withholding of feed induced endoscopically observable ulcers in the stratified squamous epithelial region of the stomach. Direct visual examination during necropsy confirmed the accuracy of endoscopic examination. (Am J Vet Res 2002;63:1076–1082)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate sensitivity of 4 commercially available microchip scanners used to detect or read encrypted and unencrypted 125-, 128-, and 134.2-kHz microchips under controlled conditions.

Design—Evaluation study.

Sample Population—Microchip scanners from 4 manufacturers and 6 brands of microchips (10 microchips/brand).

Procedures—Each microchip was scanned 72 times with each scanner passed parallel to the long axis of the microchip and 72 times with each scanner passed perpendicular to the long axis of the microchip. For each scan, up to 3 passes were allowed for the scanner to read or detect the microchip. Microchip and scanner order were randomized. Sensitivity was calculated as the mean percentage of the 72 scans for each microchip that were successful (ie, the microchip was detected or read).

Results—None of the scanners had 100% sensitivity for all microchips and both scanning orientations, and there were clear differences between scanners on the basis of operating frequency of the microchip, orientation of the microchip, and number of passes used to detect or read the microchip. For the 3 scanners designed to detect or read microchips of all 3 frequencies currently used in the United States, sensitivity was highest for 134.2-kHz microchips and lower for 125- and 128-kHz microchips. None of the scanners performed as well when only a single pass of the scanner was used to detect or read the microchips.

Conclusions and Clinical Relevance—Results indicated that use of multiple passes in different directions was important for maximizing sensitivity of microchip scanners.

Full access
in Journal of the American Veterinary Medical Association

Objective—

To compare radiographic findings and determine useful criteria to differentiate between intranasal neoplasia and chronic rhinitis in cats.

Design—

Retrospective study.

Animals—

Cats with chronic nasal disease caused by neoplasia (n = 18) or by chronic rhinitis (n = 11).

Procedure—

Radiographs were reviewed by 3 radiologists, followed by group review. Diagnosis was determined by intranasal biopsy or necropsy, and specimens were reviewed by a pathologist to confirm cause and histologic diagnosis.

Results—

Lymphosarcoma was the most common (n = 5) of the 6 histopathologic types in the neoplasia group. Cats in the neoplasia and chronic rhinitis groups had a high prevalence of aggressive radiographic lesions. Prevalence of a facial mass in cats with neoplasia (8/18) versus in those with chronic rhinitis (4/11) and of deviation (9/18 vs 6/11, respectively) or lysis (12/18 vs 7/11 ) of the nasal septum was similar. However, significantly (P = 0.02) more cats with neoplasia than with chronic rhinitis (13/16 vs 3/7, respectively) had unilateral turbinate destruction/lysis. Additionally, unilateral lateral bone erosion and loss of teeth associated with adjacent intranasal disease were more prevalent in cats with neoplasia (7/8 and 5/18, respectively) than in cats with chronic rhinitis (1/3 and 0/11, respectively).

Clinical Implications—

Features that may assist in radiographic diagnosis of neoplasia include the appearance of unilateral aggressive lesions, such as lysis of lateral bones, nasal turbinate destruction, and loss of teeth. Bilaterally symmetric lesions are more suggestive of chronic rhinitis than of neoplasia. (J Am Vet Med Assoc 1996;208:385-389)

Free access
in Journal of the American Veterinary Medical Association

Objective—

To determine the technique used, and the outcome for, double-plate fixation of comminuted fractures of the second phalanx of horses

Design—

Retrospective analysis of medical records.

Animals—

l0 horses with comminuted fractures of the second phalanx that were treated by use of double-plate fixation.

Procedure—

Two 4- to 6-hole dynamic compression plates were abaxially placed to achieve arthrodesis of the proximal interphalangeal joint and fixation of the fracture of the second phalanx.

Results—

Arthrodesis and fracture healing were detected in all horses.

Clinical Implications—

Horses with comminuted fractures of the second phalanx that are treated with double-plate fixation have an excellent prognosis for survival and use as broodstock, and have an increased potential for return to useful function.

Free access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To investigate the effects of meloxicam administration before long-distance transport on inflammatory mediators and leukocyte function of cattle at feedlot arrival.

ANIMALS 60 healthy yearling beef steers.

PROCEDURES Single-source steers were assigned to a transported (n = 40) or nontransported (20) group. Then, half of the steers within each group were assigned to receive meloxicam (1 mg/kg, PO) or a lactose placebo (1 bolus/steer, PO). All steers were transported approximately 1,300 km overnight to a feedlot; however, the nontransported group was moved before treatment (meloxicam or placebo) administration and allowed a 17-day acclimation period, whereas the transported group was moved immediately after treatment administration on day −1. Blood samples for measurement of inflammatory mediators and leukocyte function were collected from all steers on days −1, 0, and 3.

RESULTS For steers that received meloxicam, mean plasma meloxicam concentration for the transported group was significantly greater than that for the nontransported group on day 0. For steers that received the placebo, mean haptoglobin-matrix metalloproteinase-9 complex for the transported group was significantly greater than that for the nontransported group on day 0. Mean haptoglobin concentration, neutrophil L-selectin intensity, and polymorphonuclear leukocyte count for the transported group were significantly greater than those for the nontransported group. Mean substance P concentration for nontransported steers that received meloxicam was significantly lower than that for the other 3 treatment groups.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated meloxicam administration to healthy steers immediately before long-distance transport did not significantly mitigate the effects of transport-induced stress on leukocyte function or inflammatory markers.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To develop a testing algorithm that incorporates multiple assays to evaluate host cellular and humoral immunity and antigen detection concerning Mycobacterium tuberculosis complex (MTBC) infection in captive nonhuman primates.

ANIMALS

Cohorts of captive-bred and wild-caught macaques from 5 different geographic regions.

PROCEDURES

Macaques were tested for MTBC infection by use of a γ interferon tuberculosis (GIFT) assay, an interferon-γ release assay, and other assays. In the first 2 cohorts (n = 15 and 181), initial validation of the GIFT assay was performed by use of experimentally infected and unexposed control macaques. In the next 3 cohorts (n = 59, 42, and 11), results were obtained for opportunistically collected samples from macaques exposed during spontaneous outbreaks.

RESULTS

Sensitivity and specificity of the GIFT assay in the control cohorts were 100% and 97%, respectively, and were variable but enhanced by incorporating results from multiple assays in spontaneous outbreaks.

CLINICAL RELEVANCE

The detection and management of MTBC infection in captive nonhuman primate populations is an ongoing challenge, especially with animal imports and transfers. Despite standardized practices of initial quarantine with regular intradermal tuberculin skin testing, spontaneous outbreaks continue to be reported. Since infection encompasses a range of disease manifestations over time, a testing algorithm that incorporates multiple assays, such as the GIFT assay, to evaluate host cellular and humoral immunity in addition to agent detection is needed. Testing a combination of samples from controlled studies and spontaneous outbreaks of MTBC infection in nonhuman primates would advance the development and validation of a functional algorithm that incorporates promising tools such as the GIFT assay.

Open access
in American Journal of Veterinary Research