Use of 64Copper Measurements to Diagnose Canine Copper Toxicosis

Inherited canine copper toxicosis is a serious problem in Bedlington terriers and West Highland White terriers, and may also be a problem in other less-studied breeds. Affected dogs become ill at midlife with progressive and ultimately fatal liver disease. Treatments for removal of copper and prevention of copper accumulation are available, but are most effective if begun before the dog becomes ill. Until recently diagnosis has not been available until the dog is 1 year of age, and then only by an invasive liver biopsy with determination of liver copper concentration. The authors studied the use of 64copper for early diagnosis of canine copper toxicosis. Two procedures were evaluated. The first involved measuring the concentration of 64copper in blood 24 hours after oral administration of the radioisotope. At this time, 64copper was associated primarily with ceruloplasmin secreted into the blood by the liver. This procedure is useful in the diagnosis of the human counterpart, Wilson's disease. However, the authors found it to be nondiscriminatory between affected and unaffected dogs. In contrast, the second procedure, which involved measuring 64copper excreted in stool during 48 hours after an intravenous dose of radioisotope, yielded results that differentiated most affected and unaffected dogs.     

Studies on soil fumigation—III: Effects on enzyme activities,bacterial numbers and extractable ninhydrin reactive compounds

Fumigation of a field soil with chloropicrin and methyl bromide, either singly or in combination, differentially decreased soil enzyme activities and viable bacterial numbers and increased the amounts of ninhydrin reactive compounds extractable with acidified Tris buffer. Chloropicrin treatment was more effective than methyl bromide.The rates of hydrolysis of both an amide and a peptide derivative were decreased by chloropicrin treatment and remained relatively low despite changes in activities over 325 days. By contrast, caseinase activity initially was decreased by both chloropicrin and methyl bromide fumigation, but activities of the fumigated soils recovered to exceed those of untreated soils. Thereafter, caseinase activities of fumigated and untreated soils exhibited relatively large fluctuations, which were partly associated with seasonal drying of the soils in the field.Chloropicrin but not methyl bromide fumigation markedly depressed the viable bacterial populations, which subsequently increased to be above those of the untreated soils. There was no consistent relationship between the release of ninhydrin reactive compounds following fumigation and changes in bacterial numbers or changes in enzyme activity. Autolytic reactions are probably important in the early stages of amino-nitrogen release in fumigated soils. Net gains in caseinase activity may be partly due to the production de novo of extracellular proteases by microorganisms or to the release of intracellular proteases from killed cells.     

QUANTITATIVE ASSESSMENT OF SURGICALLY INDUCED MITRAL REGURGITATION USING RADIONUCLIDE VENTRICULOGRAPHY AND FIRST PASS RADIONUCLIDE ANGIOGRAPHY

Radionuclide ventriculography has been used in humans to evaluate valvular incompetency. The stroke volume ratio, derived from the radionuclide ventriculogram, is used to quantify the severity of mitral regurgitation (MR). Previous studies conducted in humans have shown that left to right stroke volume ratio increases as the severity of MR increases. In this study, we evaluated radionuclide ventriculography as a noninvasive method to detect MR in dogs with surgically created mitral insufficiency. Six male and three female adult, conditioned mongrel dogs were used. Scintigraphic studies were performed prior to and 4 weeks after surgically created MR. Because of the overlap of the left and right ventricles when viewed from a left lateral position, we combined data from a first-pass radionuclide angiocardiogram with the radionuclide ventriculogram to obtain a corrected stroke volume ratio. Blood flow transit parameters were also derived from the first-pass radionuclide angiocardiogram. Standard left ventricular functional indices were also measured from the radionuclide ventriculogram. On the left lateral view of the heart, 25 to 30% of the right ventricular volume overlaps the left ventricle. After correcting for the overlap, the stroke volume ratio of normal dogs was 1.17±0.178 (mean±SD), which increased to 2.06±0.41 (mean±SD) (p<.001) 4 weeks after creation of MR. The was no significant change in left ventricular ejection fraction or peak rate of ejection following MR. The transit times of blood through the left ventricle were measured from the first-pass radionuclide angiocardiogram and were expressed as half-time clearance, peak clearance rate, and time to peak clearance rate. The baseline half-time clearance was 2.07±0.71 s (mean±SD), which increased to 6.70±4.89 s (mean±SD) (p=.02) after creation of MR. The baseline peak clearance rate was 49.75±8.96 cts/s (mean±SD), which decreased to 23.12±6.84 cts/s (mean±SD) (p<.001) after creation of MR. Stroke volume ratios significantly increased following creation of MR. Blood flow transit through the left ventricle slowed following creation of MR. The variability of these parameters were small in the baseline studies, suggesting these techniques may be clinically useful to gauge the severity of MR in dogs.     

Acute and chronic hormone and metabolite changes in lambs fed the beta-agonist, cimaterol

The objective of this study was to determine if acute and chronic changes in circulating metabolic hormone and metabolite concentrations are associated with β-agonist-induced nutrient repartitioning in young growing lambs. Two groups of 12 Dorset and Dorset-Finn cross ram lambs weighing 36 or 33 kg live weight were assigned to 3- or 6-week treatment intervals, respectively, to achieve similar slaughter weights. Six lambs within each treatment interval were fed ad libitum a complete mixed high-concentrate diet containing either 0 or 10 ppm cimaterol. During the first 12 hr of cimaterol administration plasma somatotropin (ST), thyroxine (T₄), and triiodothyronine (T₃) concentrations were not altered by treatment, but plasma insulin, glucose, non-esterified fatty acids (NEFA) and glycerol concentrations were elevated 2 hr after ingestion. These acute responses suggest direct stimulation of glycogenolysis and lipolysis by cimaterol, which is characteristic of β-adrenergic alteration of carbohydrate and lipid metabolism. Chronic administration of cimaterol significantly decreased insulin concentrations by 36% and 52% at 3 and 6 weeks, respectively, while glucose concentrations remained unchanged. Serum IGF-I concentrations were not significantly altered by cimaterol. T₄ levels were reduced 22.1% after 3 weeks of cimaterol treatment. Although plasma NEFA concentrations were chronically elevated 56% to 65% in lambs fed cimaterol, plasma glycerol concentrations remained at baseline levels. The relative changes in plasma NEFA and glycerol concentrations are consistent with a decreased rate of lipogenesis, rather than an increase in lipolysis.     

The use of ultrasonography in the reproductive evaluation of boars

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty‐six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.     

Characterization of age- and location-associated variations in the composition of articular cartilage from the equine metacarpophalangeal joint

Objective: To characterize the impact of age, gender, location and individual animal variation on the composition of articular cartilage from the metacarpophalangeal joint of horses. Design: Cartilage specimens were obtained from the metacarpophalangeal joints of 28 male, female and castrated male horses ranging in age from one day to 27 years of age. Cartilage samples from the distal metacarpus, proximal first phalanx and proximal sesamoids were analyzed separately. Chondrocyte number, DNA content, proteoglycan concentration and total collagen content were determined for each animal and joint location. Results: Age and joint location had a significant effect on chondrocyte number and DNA content with higher cell counts and DNA content detected in cartilage from the youngest age groups and in cartilage from the metacarpus and proximal sesamoids. The influence of age on chondrocyte numbers was not significant in horses over two years of age. Both age and joint location also influenced total proteoglycan and collagen content. Lower proteoglycan and collagen concentrations were detected in younger horses, and cartilage from the metacarpus had lower proteoglycan and collagen concentrations than that from other joint locations. Gender did not appear to influence chondrocyte number or matrix content of equine articular cartilage. However, there was significant residual variation in cellularity, proteoglycan levels and collagen content between individual animals that could not be explained by the signalment factors considered in this study. Conclusions: Future studies examining equine articular cartilage should avoid direct morphologic comparisons between animals of different ages, and any comparisons made between individuals should be interpreted cautiously. In addition, in vitro tissue culture models should avoid the use of cartilage pooled from different animals or from different locations within the same joint.