Tissue gamma-glutamyl transpeptidase activity and hepatic ultrastructural alterations in dogs with experimentally induced glucocorticoid hepatopathy

Glucocorticoid hepatopathy was induced in 2 Beagle dogs with IM injections of prednisone, 4.4 mg/kg, given once daily for 14 consecutive days. Serum enzymatic activities were monitored and percutaneous hepatic biopsy materials were collected. A placebo-treated group of 2 Beagle dogs was given saline solution injections. Treated dogs showed clinical signs of Cushing's disease and alterations in mean serum enzymatic activities consistent with glucocorticoid hepatopathy. The gamma-glutamyl transpeptidase activities in placebo-treated dogs were highest for kidney, less (but marked) for pancreas, and least for liver, gallbladder, jejunum, duodenum, spleen, heart, lung, skeletal muscle, and erythrocytes. In treated dogs, the gamma-glutamyl transpeptidase activities were highest for pancreas and were decreased for kidney and slightly increased for the other tissues. Results of hepatic biopsy and necropsy examinations of treated dogs showed swollen, pale, friable hepatic parenchyma with hepatocytic cytoplasmic vacuolation and glycogen accumulation. Extrahepatic lesions included gastric ulceration, catarrhal enteritis, splenic and lymph node atrophy and lymphocytolysis, and vacuolation of adrenal cortical cells in the zona fasciculata. Ultrastructural study of liver from dogs with glucocorticoid hepatopathy indicated that the principle alterations were abundant glycogen accumulation and few mitochondria in hepatocytes.     

Urinary gamma-glutamyl transpeptidase activity in dogs with gentamicin-induced nephrotoxicity

Serum creatinine concentrations, 24-hour endogenous creatinine clearance, and 24-hour urinary gamma-glutamyl transpeptidase (UGGT) activity were measured daily in 6 dogs given nephrotoxic dosages of gentamicin (10 mg/kg of body weight) every 8 hours for 10 days. Mean UGGT activity was significantly increased by day 5 (P less than 0.05) and preceded significant increases in serum creatinine values (greater than 2.0 mg/dl) observed on day 9. Endogenous creatinine clearance remained within normal limits (2.98 +/- 0.96 ml/min/kg) until day 8. Urinalyses performed 8 days after initiation of gentamicin treatment indicated renal tubular damage (granular casts) in 1 of the 6 dogs, and glucosuria in 3 of the 6 dogs. Measurement of UGGT activity was a more sensitive and reliable method of assessing acute renal tubular damage induced by gentamicin than were serum creatinine concentrations or 24-hour endogenous creatinine clearance.     

Serum gamma glutamyl transpeptidase activity in cattle with induced fascioliasis

Six-month-old calves were inoculated with 200 metacercariae of Fasciola hepatica over a 72 day period. Their aspartic transaminase, alkaline phosphatase, arginase and gamma glutamyl transpeptidase (GGT) values were measured at two-week intervals. Infections with a final fluke count of 19 to 87 flukes did not result in an increase of serum alkaline phosphatase or arginase compared with those in control calves. Serum aspartic transaminase values were increased significantly (P less than 0.025) above those of controls but were not increased over reference values. Seemingly, measurement of these enzymes would not be useful in assessing the degree of fluke infestation. In contrast, serum values of GGT increased 56 days after preliminary inoculation and remained high for at least 83 days after infection. The initial rise coincided with the penetration of bile ducts by migrating flukes. This relationship may be useful in further studies of fluke-induced biliary damage.     

Serum cobalamin concentrations in healthy cats and cats with non-alimentary tract illness in Australia

Objective   To determine a reference range for serum cobalamin concentration in healthy cats in Australia using a chemiluminescent enzyme immunoassay and to prospectively investigate the prevalence of hypocobalaminaemia in cats with non-alimentary tract disease.
Design   Prospective study measuring serum cobalamin concentrations in clinically healthy cats and cats with non-alimentary tract illness.
Procedure   Blood was collected from 50 clinically healthy cats that were owned by staff and associates of Veterinary Specialist Services or were owned animals presented to Creek Road Cat Clinic for routine vaccination. Blood was collected from 47 cats with non-alimentary tract illness presented at either clinic. Serum cobalamin concentration was determined for each group using a chemiluminescent enzyme immunoassay.
Results   A reference range for Australian cats calculated using the central 95th percentile in the 50 clinically healthy cats was 345 to 3668 pg/mL. Median serum cobalamin concentration in 47 cats with non-alimentary tract illness (1186 pg/mL; range 117–3480) was not significantly different to the median serum cobalamin of the 50 healthy cats (1213 pg/mL, range 311–3688). Using the calculated reference range one sick cat with non-alimentary tract illness had a markedly low serum cobalamin concentration.
Conclusion   Although hypocobalaminaemia is uncommon in sick cats with non-alimentary tract illness in Australia, its occurrence in this study warrants further investigation.     

Red cell morphologic alterations in cats with hepatic disease

Medical records from 39 cats with hepatic disease, examined at the Veterinary Medical Teaching Hospital, University of Florida, between 1987 and 1992 were retrospectively evaluated for alterations in red blood cell (RBC) morphology. Diagnoses included: hepatic lipidosis, neoplasia, cholangiohepatitis, hepatitis/hepatopathy, systemic histoplasmosis, and portocaval shunt. A total of 56 laboratory data sets were studied which included complete blood counts and serum chemistry results. Stained blood smears were evaluated from 51 of the data sets. Twenty-two cats (56%) were determined to have poikilocytosis on the basis of blood smear evaluation. Eleven (28%) cats had moderate to marked poikilocytosis (2+ to 4+). Acanthocytes accounted for 62.6 -/+ 22.1% of morphologically abnormal RBC and were observed in blood smears from 100% of cats with poikilocytosis. Elliptocytes (ovalocytes) comprised 19.5 -/+ 15.8% of poikilocytes and were found in smears from 82% of cats with poikilocytosis. Keratocytes (7.0 -/+ 6.8%), schistocytes (3.6 -/+ 4.4%), and blister cells (2.6 -/+ 6.4%) were present in lower numbers and in fewer cats. Serum total cholesterol values were significantly greater (p < 0.05) in cats with moderate to marked alterations in RBC morphology. Cats with hepatic lipidosis were significantly (p < 0.04) more likely to have poikilocytosis than cats with other types of hepatic disease.     

Evaluation of plasma C-terminal atrial natriuretic peptide in healthy cats and cats with heart disease

BACKGROUND: The clinical implications of evaluating C-terminal atrial natriuretic peptide (ANP) concentration in cats are still controversial. HYPOTHESIS: The objective of this study was to investigate the relationship between plasma C-terminal ANP concentration and left atrial pressure (LAP) in healthy cats with volume overload (study 1), and to compare plasma C-terminal ANP in normal cats and cats with cardiomyopathy (study 2). ANIMALS: Five healthy adult cats were used in study 1, and clinically healthy cats (n=8) and cats with cardiomyopathy (n=14) were used in study 2. METHODS: In study 1, cats were anesthetized and given acetated Ringer's solution (100 mL/kg/h for 60 minute) via the cephalic vein. Hemodynamic measurements and blood samples, collected from the jugular vein, were performed at 10-min intervals. In study 2, blood samples from normal cats and cats with cardiomyopathy were collected from the cephalic vein. The plasma C-terminal ANP concentration was determined by radioimmunoassay for human alpha-ANP. RESULTS: In study 1, volume overload significantly increased the C-terminal ANP concentration and LAP from baseline. The C-terminal ANP concentration was strongly correlated with the mean LAP. In study 2, age, E wave velocity, and the ratios of the left atrium to aorta were significantly higher in the cats with cardiomyopathy compared with the normal cats. The C-terminal ANP concentration was significantly higher in the cats with cardiomyopathy compared with the normal cats. CONCLUSIONS AND CLINICAL IMPORTANCE: Our results suggest that the measurement of plasma C-terminal ANP in cats may provide additional information for the diagnosis of heart disease.     

Serum creatine kinase activity in dogs and cats with metabolic diseases

Elevated Creatine kinase-activitiy (CK) indicates disturbances of the muscle cell integrity. In addition to primary muscle disease, like trauma, inflammation or dystrophy, diseases of other organs can lead to secondary muscle involvement, which will be indicated by increased serum activities of the CK. The mechanisms of muscle cell disturbance are still unknown. An elevated protein catabolism in the muscle cell is suspected. In the present study we investigated, if dogs and cats with metabolic diseases have increased CK-activity in the serum. From 34 dogs and cats in a group with different metabolic diseases without metabolic acidosis 19% of the dogs and 50% of the cats had increased CK-activity in the serum. From 33 dogs and cats with different metabolic diseases connected with metabolic acidosis 86% of the dogs and 95% of the cats had simultaneously increased CK-activity in the serum. In comparison to healthy dogs and cats animals with metabolic diseases have significant and in cases of metabolic di-seases with metabolic acidosis cats have high significant elevation (dogs significant) of CK-activity in the serum. There was no significant correlation between the groups of patients. In conclusion we think that our results show that metabolic diseases often induce secondary myopathy, measured by CK-activity in the serum, but metabolic acidosis has no direct influence on elevated CK activity in dogs and cats.     

Myocardial taurine concentrations in cats with cardiac disease and in healthy cats fed taurine-modified diets.

Myocardial taurine concentrations were measured in cats with cardiac disease and in healthy cats fed diets with various concentrations of taurine. Group 1 was composed of 26 cats with 3 categories of naturally developing cardiac disease: dilatative cardiomyopathy (group 1A), 10 cats; hypertrophic cardiomyopathy (group 1B), 9 cats; and volume overload (group 1C), 7 cats. These cats had been fed various commercial diets. Group 2 was composed of 40 healthy cats that had been fed diets varying in taurine concentration (0 to 1% taurine) for at least 2 years. Mean myocardial taurine concentrations did not differ significantly between group-1 cats with dilatative cardiomyopathy and those with hypertrophic cardiomyopathy or volume overload. Cats in group 1A had a mean myocardial taurine concentration 3 times higher than healthy cats fed a taurine-free diet (P less than 0.002). Mean myocardial taurine concentrations did not differ significantly between group-1A cats and healthy cats fed a diet containing 0.02% taurine; group-1A cats had significantly lower mean myocardial taurine concentrations than did healthy cats fed a synthetic diet containing 0.05 or 1.0% taurine (P less than 0.001). Acute oral administration of taurine in 5 group-1A cats appeared to increase mean myocardial taurine concentrations, compared with similar cats not given taurine during treatment for cardiac failure. In group-2 cats, mean myocardial taurine concentrations increased directly with percentage of dietary taurine.     

Fine-needle aspirate cytology suggesting hepatic lipidosis in four cats with infiltrative hepatic disease

Four cats are reported in which cytology smears obtained by ultrasound-guided fine needle aspiration of the liver were interpreted as indicative of hepatic lipidosis. However, histopathology of hepatic tissue samples obtained with Tru-Cut-like needles or wedge biopsy revealed that the cats had inflammatory or neoplastic hepatic disease causing their clinical signs. Fine needle aspiration and cytology may not detect infiltrative lesions, particularly those that are nodular, multifocal, or localised around the portal regions. Fine needle aspirate cytology is a useful diagnostic procedure with many advantages, but care must be taken to avoid diagnosing hepatic lipidosis as the cause of illness when an infiltrative lesion is responsible.     

Serum alhpa 1-acid glycoprotein concentrations in healthy and tumor-bearing cats

The purpose of this study was to evaluate alpha 1-acid glycoprotein (AGP) concentrations in tumor-bearing and healthy cats. The hypothesis of the present study was that AGP concentrations would be significantly increased in tumor-bearing cats. Serum from 51 healthy and 97 tumor-bearing, client-owned cats was harvested at the time of presentation and stored at -80 degrees C until assayed. Cats with measurable, histologically confirmed malignancies, and healthy cats of similar ages were included. Serum was assayed for AGP concentration by using a radial immunodiffusion method. AGP concentrations were significantly (P = .0051) higher in tumor-bearing (763 +/- 595 microg/mL; mean +/- SD) when compared to healthy cats (501 +/- 377 microg/mL; mean +/- SD). Of the tumor-bearing cats, 35 had carcinomas, 33 had sarcomas, and 26 had discrete, round cell tumors. AGP concentrations were 645 +/- 62 microg/mL, 660 +/- 540 microg/mL, and 967 +/- 860 microg/mL, respectively, and there were no significant differences among the groups.     

Comparison of plasma, liver, and skeletal muscle carnitine concentrations in cats with idiopathic hepatic lipidosis and in healthy cats

Concentrations of total, free, and esterified carnitine were determined in plasma, liver, and skeletal muscle from cats with idiopathic hepatic lipidosis and compared with values from healthy cats. The mean concentrations of plasma, liver, and skeletal muscle total carnitine; plasma and skeletal muscle free carnitine; and plasma and liver esterified carnitine were greater (P less than 0.05) in cats with idiopathic hepatic lipidosis than in control cats. The mean for the ratio of free/total carnitine in plasma and liver was lower (P less than 0.05) in cats with idiopathic hepatic lipidosis than in control cats. These data suggest that carnitine deficiency does not contribute to the pathogenesis of feline idiopathic hepatic lipidosis.     

Evaluation of plasma antithrombin activity and D-dimer concentration in populations of healthy cats, clinically ill cats, and cats with cardiomyopathy

BACKGROUND: Current coagulation tests lack sensitivity and detect disseminated intravascular coagulation (DIC) only when it is severe. Measurement of antithrombin (AT) activity and D-dimer concentration permits early diagnosis and more precise classification of coagulopathies in some species. OBJECTIVES: The objectives of this study were to validate and determine the diagnostic utility of a chromogenic AT assay and an immunoturbidimetric D-dimer assay for the diagnosis of DIC in cats. METHODS: Citrated plasma samples were collected from 30 healthy cats, 30 ill cats, and 13 cats with cardiomyopathy. Partial thromboplastin time, prothrombin time, fibrin(ogen) degradation products, platelet concentration, and erythrocyte morphology were determined on all samples to document the presence or the absence of DIC. AT activity and D-dimer concentration were then measured. RESULTS: The chromogenic AT assay was linear and precise. Mean AT activity was higher in ill cats and cats with cardiomyopathy compared with healthy cats, but the difference was only significant in ill cats (P = .003). Seven cats met the criteria for DIC. Of the cats with DIC, 2 had decreased AT activity, 1 had increased AT activity, and 4 had AT activities within normal limits. The immunoturbidimetric D-dimer assay did not appear to accurately measure feline D-dimer. CONCLUSIONS: The chromogenic AT assay appeared to measure AT in cats but was not useful for the diagnosis of DIC. AT may be an acute phase reactant in cats. The immunoturbidimetric D-dimer assay was not useful for the diagnosis of DIC in cats.     

Effect of clindamycin on factor-VII activity in healthy cats

Four healthy cats were given clindamycin orally in daily doses of 25 or 50 mg/kg of body weight for 6 weeks. Significant change in Factor-VII activity was not found, compared with pretreatment values. In 2 cats tested, toxin produced by Clostridium difficile was not detected in fecal samples obtained before treatment and at 6 weeks after treatment, suggesting that intestinal overgrowth by C difficile did not develop. Results of the study seemed to indicate that orally administered clindamycin does not measurably reduce synthesis of vitamin K-dependent clotting factors in healthy cats.     

Blood pressure assessment in healthy cats and cats with hypertensive retinopathy

OBJECTIVE: To determine whether there was an association between hypertensive retinopathy and high systolic, diastolic, and mean arterial blood pressures in cats. ANIMALS: 181 cats. PROCEDURE: Systolic, diastolic, and mean arterial blood pressures were measured by use of a noninvasive oscillometric technique. The range of blood pressure measurements in healthy cats from various age groups was determined. Associations among systolic, diastolic, and mean arterial blood pressure; hypertensive retinopathy; hyperthyroidism; left ventricular cardiac hypertrophy; chronic renal failure; and serum biochemical abnormalities were determined. RESULTS: All blood pressure measurements increased with age in healthy cats. The frequency of hypertensive retinopathy also increased with age and with blood pressure, and hypertensive retinopathy was particularly found in cats with systolic blood pressures > 168 mm Hg. There was an increased risk for hypertensive retinopathy in cats that were female, > 10 years old, and neutered. The risk of chronic renal failure also increased as blood pressure, particularly systolic blood pressure, increased. CONCLUSIONS AND CLINICAL RELEVANCE: Hypertensive retinopathy was common in cats > or = 10 years of age and was associated with systolic blood pressures > 168 mm Hg when measured by the noninvasive oscillometric technique.     

Serum bile acids and the assessment of hepatic function in dogs and cats

Current literature in veterinary internal medicine regarding the clinical use of the serum bile acids test to assess hepatobiliary function in dogs and cats is reviewed. The test is best used in cases where clinical signs and routine laboratory tests are suggestive of liver disease. It is a highly sensitive and specific test of hepatic function, and is the best method of assessing liver function available to the private practitioner. Abnormal results do not determine etiology, severity, or prognosis of the disorder. They merely indicate the need for hepatic biopsy. The serum bile acids concentration should always be measured in both a fasting and a two-hour postprandial sample.