The use of serum enzymes as diagnostic aids in the dog

Clinical enzymology of the dog and cat

Clinical enzymology studies the enzyme activity in serum or other body fluids for the diagnosis, prognosis or monitoring of a variety of diseases. Clinical enzymology has greatly benefited from advances in technology and is now an integral part of laboratory analysis. However, to maximise the clinical benefits of serum enzyme measurement, clinicians and clinical pathologists must have a good understanding of the pathophysiology behind serum enzyme alterations. They must also be aware of the preanalytical and analytical factors that can affect the accuracy of serum enzyme activity measurement. This review article first covers the basic concepts of clinical enzymology and the general mechanisms related to serum enzyme alterations. Then, the review discusses the potential effects of various preanalytical and analytical factors on enzyme activity measurement. Lastly, it explores the pathophysiology and clinical use of various serum enzymes in canine and feline medicine. The present review article aims to be a comprehensive one-stop source for clinical pathologists and small animal practitioners.

Serum alkaline phosphatase activity in Scottish Terriers versus dogs of other breeds

OBJECTIVE

To determine whether Scottish Terriers have higher serum alkaline phosphatase (ALP) activities and a higher prevalence of diseases commonly associated with high serum ALP activity than do dogs of other breeds.

DESIGN

Retrospective case-control study.

ANIMALS

85 Scottish Terriers and 340 age-matched control dogs that were not Scottish Terriers.

PROCEDURE

Medical records were reviewed, and data for year of evaluation, age, sex, breed, serum ALP activity, and final diagnosis were recorded.

RESULTS

Scottish Terriers had a significantly higher mean serum ALP activity than did control dogs (1,520 U/L vs 306 U/L). Regardless of breed, dogs that had a disease commonly associated with high serum ALP activity had a significantly higher mean serum ALP activity than did dogs without such diseases (1,304 U/L vs 427 U/L). Scottish Terriers were 2.4 times as likely to have a disease commonly associated with high serum ALP activity than were control dogs, but Scottish Terriers with diseases commonly associated with high serum ALP activity had a significantly higher mean ALP activity than did control dogs with such diseases (2,073 U/L vs 909 U/L), and Scottish Terriers without such diseases had a significantly higher mean serum ALP activity than did control dogs without such diseases (1,349 U/L vs 228 U/L).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that Scottish Terriers have higher serum ALP activities than do dogs of other breeds. Although Scottish Terriers also have a higher prevalence of diseases associated with high serum ALP activity, this alone did not explain the higher mean serum ALP activity in the breed.

Assessment of hepatic function and damage in animal species. Animal Clinical Chemistry Association

There are a wide variety of laboratory tests available to assess damage to and functional impairment of the liver, though the effectiveness of these tests varies greatly depending upon the type of damage and the animal species involved. Species differences in tissue localization, metabolism, specificity and sensitivity of parameters relating to the liver influence the choice of tests. Some tests can be applied usefully to most animal species while others may be highly specific in one species but show very low discriminatory potential in others. The tests available, and their use in veterinary and toxicological investigations have been reviewed in the light of current practice in the U.K.

The characteristic pattern of aspartate aminotransferase and alanine aminotransferase in the bitch with the cystic hyperplasia-pyometra complex: effect of medical or surgical treatment

In 75 clinically normal unspayed female control dogs between two and eleven years old the average plasma level of aspartate aminotransferase (AST) was 21.6 +/- 5.7 (+/- SD) IU/l, of alanine aminotransferase (ALT) 40.4 +/- 13.0 IU/l and of the AST/ALT ratio 0.6 +/- 0.2. These values showed only minor changes over years. In 96 bitches with the cystic hyperplasia-pyometra complex there was a very significant increase of the AST, decrease of the ALT and increase of the AST/ALT ratio. The changes were more pronounced in 62 clinically ill bitches with typical endometritis post oestrum, in 18 dogs with gram negative organisms in the uterus and in 53 bitches with white blood cell (WBC) levels higher than 40 X 10(9)/1. Renal failure had no influence on the specific changed values. The changed values returned either temporarily to normal after prostaglandin (PGF2 alpha)-treatment or definitely after ovariohysterectomy.

Ochratoxicosis in Beagle dogs. II. Pathology

The gross lesions in 23 young male Beagle dogs given daily oral doses of 0.2–3.0 mg/kg body weight ochratoxin A consisted of moderate to severe mucohemorrhagic enteritis of the cecum, colon, and rectum; tonsillitis: and enlargement of lymph nodes, which were edematous, hyperemic and focally necrotic. Histopathologic alterations in the kidneys consisted of necrosis and desquamation of epithelial cells mainly in, but not limited to, proximal convoluted tubules. Many proximal and distal convoluted tubules contained eosinophilic, granular casts. Necrosis of lymphoid tissues was a prominent feature of the mycotoxicosis and focally occurred in, but was not limited to, germinal centers in the spleen, tonsils, thymus, and lymph nodes and the lymphoid nodules of the jejunum, ileum, cecum, colon, rectum and nictitating membrane. Necrosis did not occur in bone marrow. Hepatic alterations consisted of slight to moderate centrilobular necrosis and fatty change and occurred mainly in dogs receiving 0.2–0.3 mg/kg body weight ochratoxin A daily for 11–14 days.

Ochratoxicosis in Beagle dogs. I. Clinical and clinicopathological features

Rice culture of Aspergillus ochraceus that contained ochratoxin A or pure crystalline ochratoxin A was administered orally daily to 23 young male Beagle dogs. Six other young male Beagles served as controls. Most dogs were killed in extremis on or before day 14 after receiving a daily oral dose of ochratoxin A, 0.2–3.0 mg/kg body weight. Consistent clinical features of the mycotoxicosis were anorexia, weight loss, emesis, tenesmus, passage of clots of blood-stained mucus from the rectum, rectal temperature up to 107°F, tonsillitis, dehydration and prostration. The prominent clinicopathological features of the toxicosis were a reflection of renal damage. The urine had a specific gravity as low as 1.004 and contained granular casts, necrotic renal epithelium, and concentrations above normal of protein, glucose, lactic dehydrogenase, isocitric dehydrogenase, leucine aminopeptidase, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase, and alkaline phosphatase. Serum concentrations of these enzymes did not change. Concentrations of blood urea nitrogen remained, with two exceptions, within the normal range, but the concentrations of blood glucose declined terminally. Serum concentrations of the liver-specific enzyme, γ-glutamyl transpeptidase and sulfabromophthalein dye retention time did not indicate hepatic dysfunction.