Abnormal microheterogeneity of haptoglobin in serum from dogs with various diseases.

Changes in the patterns of glycosylation of canine haptoglobin have recently been demonstrated by isoelectric focusing and immunoblotting. Fucosylated fractions of haptoglobin were identified by selective binding of a fucose-specific lectin. In this study, similar changes were found in the serum of 86 of 137 dogs with various inflammatory, autoimmune and neoplastic diseases. Major changes, including fucosylation, were observed in 40 of the dogs and were most frequent in association with autoimmune haemolytic anaemia. All 40 cases had markedly increased concentrations of haptoglobin and decreased concentrations of haemoglobin. Minor changes were found in the other 46 dogs, whereas no changes in glycosylation were detected in the serum of 40 healthy dogs.

Disease-related variations of the glycosylation of haptoglobin in the dog.

Haptoglobin phenotypes have been shown in human medicine to be related to the prevalence of various diseases. Furthermore, abnormal glycosylation of haptoglobin has been reported as a consequence of liver disease, cancer and immunological disorders in man. To our knowledge, similar findings have not, so far, been reported in canine disease. The present paper describes a method for investigation of canine haptoglobin phenotypes and of microheterogeneity caused by altered glycosylation. The method consisted of isoelectric focusing (IEF) of dog serum, followed by immunoblotting. The results indicated the existence of only one canine haptoglobin phenotype with a characteristic microheterogeneity pattern in healthy dogs. Changes in this pattern were found in serum from dogs with liver disease, predominantly chronic progressive hepatitis, and with different kinds of anaemia. Pretreatment of serum with neuraminidase or glycopeptidase F (PNGase F) resulted in identical IEF patterns of haptoglobin from healthy and diseased dogs. Moreover, a fucose-specific lectin was capable of binding to some of the abnormal haptoglobin fractions, mainly those found in association with anaemia. The changes described were interpreted as alterations of the carbohydrate content, with or without fucosylation, of some haptoglobin fractions.

Elastase inhibitory capacity of purified canine alpha-1-antitrypsin.

In a previous study, isoelectrofocusing of serum from liver-diseased and healthy dogs revealed three different types of the acute phase protein, alpha-1-antitrypsin: Pi (protease inhibitor) F, Pi I and Pi S. Moreover, accumulated alpha-1-antitrypsin was found immunohistochemically in liver sections from dogs with chronic liver disease, predominantly in association with Pi I in serum. The present study was made to further the relationship between alpha-1-antitrypsin and the pathogenesis of chronic liver disease in dogs. Aliquots of samples of purified canine Pi F, Pi I and Pi S were examined for elastase inhibitory capacity, the main function of alpha-l-antitrypsin, and for polymerization tendency, a possible cause of accumulation of alpha-1-antitrypsin in the liver. These parameters were studied after incubation of the proteins at different temperatures (4, 37 and 42 degrees C) and pH values (6.8, 7.8 and 8.5) and for different periods (< or = 24 h and 5 days). In contrast to findings with Pi Z, the human alpha-1-antitrypsin variant associated with liver disease, polymers of canine Pi F, Pi I or Pi S could not be detected under any of the conditions tested. However, Pi I was sensitive to pH, as was demonstrated by reduced elastase inhibitory capacity after incubation at pH 6.8 for < or = 24 h or 5 days, or at pH 8.5 for 5 days. However, after incubation at pH 7.8 for < or = 24 h or 5 days at 4, 37 or 42 degrees C, Pi I was completely stable. Pi F retained its elastase inhibitory capacity, even after prolonged incubation, at all pH values and temperatures tested. Due to low yield, Pi S was tested only after incubation for < or = 24 h at pH 6.8 and at 4 degrees C; under these conditions its elastase inhibitory capacity was equal to that of Pi F. Taken together, these findings indicate molecular and functional differences between Pi I and Pi F and further support a role for alpha-1-antitrypsin in the pathogenesis of canine liver disease.

Diagnosis and prognosis of chronic hepatitis and cirrhosis in dogs.

The purpose of this investigation was to evaluate the significance of enzymatic and biochemical analyses in the classification of chronic inflammatory liver disease and to evaluate the prognosis of these diseases. Chronic hepatitis and cirrhosis were diagnosed by histopathological examination in 79 dogs. Decreased appetite and lethargy were the most common owner complaints (46/79). Vomiting and, or, diarrhoea were reported in 27/79 dogs. Ascites was the most common clinical sign (43/79), whereas icterus was a more unusual finding demonstrated in 16/79 dogs. Liver cirrhosis was diagnosed most frequently, in 33/79 dogs, followed by chronic progressive hepatitis (22/79), chronic cholangiohepatitis (13/79), and chronic non-specific hepatitis (11/79). Hypoalbuminaemia was the most consistent biochemical aberration in liver cirrhosis (25/26) and in chronic progressive hepatitis (13/18). These diseases also showed normal to mildly increased concentrations of serum alanine aminotransferase (ALT) and serum gamma-glutamyl transferase (GGT) and a moderate to marked increase of serum alkaline phosphatase (ALP) and fasting serum bile acid (SBA) concentrations. As expected, icterus and markedly elevated ALT, ALP, GGT and SBA levels were demonstrated in chronic cholangiohepatitis. In this disease hypoalbuminaemia was shown in 6/12 dogs, whereas in dogs with chronic non-specific hepatitis, mean SBA and albumin concentrations were normal. In liver cirrhosis the prognosis was poor, with 94 per cent of the dogs dead within one week of established diagnosis. For dogs with the other types of chronic hepatitis the prognosis was more favourable with the mean survival time ranging from 21.1 to 36.4 months.

Serum protein electrophoresis as a prognostic marker of chronic liver disease in dogs.

In a previous study in dogs with chronic liver disease it was found that a combination of clinical features and laboratory findings was useful in differentiating liver diseases but could not be used to evaluate a dog's prognosis. When an electrophoretic analysis of the serum proteins was included, marked decreases in the concentrations of albumin and the alpha-globulins alpha-1-antitrypsin and haptoglobin were observed in terminal liver cirrhosis, indicating impaired liver function. However, low albumin concentrations, together with normal or increased concentrations of alpha-1-antitrypsin and haptoglobin, were observed in dogs which, although severely depressed when examined, often recovered and survived for a year or more.

Hepatic accumulation of alpha-1-antitrypsin in chronic liver disease in the dog.

Alpha-1-antitrypsin deficiency has long been known to cause liver cirrhosis in man, but whether it does so in the dog is uncertain. To investigate this point 57 dogs with clinically and histopathologically diagnosed chronic liver disease were examined. Isoelectric focusing of blood serum from these dogs and from 25 clinically healthy dogs revealed three different types of alpha-1 antitrypsin, designated F(fast), I(intermediate) and S(slow). They appeared in both homozygous and heterozygous forms, the F type being seen most frequently. The I type was more common in cocker spaniels than in other breeds. Immunostaining for alpha-1 antitrypsin revealed that 37 diseased dogs had alpha-1 antitrypsin in the cytoplasm of their hepatocytes. Of these, 21 dogs had globular alpha-1 antitrypsin inclusions in the endoplasmic reticulum, indicating aggregated protein. Accumulated alpha-1 antitrypsin was found most frequently in dogs having the I and S types of alpha-1 antitrypsin, either homozygously or heterozygously. With a few exceptions, F-homozygotic dogs had no hepatocellular alpha-1 antitrypsin accumulation. As alpha-1 antitrypsin aggregation is lethal to hepatocytes and as cell death attracts mononuclear blood cells whose cytokines induce continued alpha-1 antitrypsin synthesis with subsequent risk of further alpha-1 antitrypsin accumulation, liver disease may thus be maintained. Whether alpha-1 antitrypsin aggregates actually initiate liver disease in dogs, as in man, remains to be elucidated by further biochemical investigation of the three canine alpha-1 antitrypsin types found.

Dietary management in urolithiasis in the dog.

Struvite uroliths are found more frequently than other types of uroliths in the urinary tracts of dogs. Medical dissolution of struvite uroliths with a Swedish calculolythic diet has been evaluated. The palatability of the diet was good and only two out of a total of 69 dogs in the study could not be maintained on the diet because of diarrhea. In 19 of 33 dogs medically treated, the uroliths were dissolved over a period of one to 6 months (mean time 2.5 months). In the remaining dogs uroliths were surgically removed, and calculolytic diet was postoperatively given. Consumption of the calculolytic diet was in most cases associated with a lowered specific gravity and pH of the urine. A representative case report of medical dissolution of struvite uroliths located in the urinary bladder of a 9 year-old female cocker spaniel with a history of recurrent urolithiasis is described. It is concluded that the Swedish calculolytic diet can be used successfully to dissolve struvite in adults dogs.