Ultrastructural and kinetic studies of copper metabolism in Bedlington Terrier dogs.

The objectives of this study were to determine the time course of copper (Cu) absorption in the Bedlington Terrier (BT) dog after duodenal infusion of Cu and to determine the onset of Cu accumulation in BT puppies. At 80 minutes after infusion, Cu was present in the bile and liver at 26.1 and 2675 microg/g dry weight (dw), as compared with 598 and 224 microg/g dw, respectively, in the control. In the puppies, the mean liver Cu concentrations were 443 +/- 216 microng/g dw as compared with 54 +/- 34 microg/g dw in their controls. The BT puppies had large numbers of Cu granules in their hepatic lysosomes, with very few in the bile canaliculi. In contrast, the controls had few granules in their lysosomes and large numbers in their canaliculi. These results suggest that hepatic Cu accumulation occurs rapidly and in utero in the BT.

Changes in bile acid composition of serum and gallbladder bile in bile duct ligated dogs.

Biliary obstruction was produced by surgical ligation of the common bile duct to observe alterations in serum bile acid composition. The percent composition of serum bile acids was found to change with time. Taurocholic acid increased on day 3 and accounted for more than 90% of the total bile acids in all dogs, however it decreased after day 7. The percentage of taurochenodeoxycholic acid (TCDC) and taurodeoxycholic acid (TDC) decreased to 4.2-6.0% and 0.2-0.7% on day 3, respectively. However, the percentage of TCDC increased after day 7 in all dogs and reached greater than 20% on day 14 in 2 dogs, whereas the percent TDC after bile duct ligation remained low in all dogs. Glycolithocholic acid, which was not identified in normal dog sera, was detected on day 3 and remained throughout the study in all dogs. Bile acid composition of gallbladder bile sampled on day 35 was similar to the serum bile acid composition on the same day. This indicates that the bile acids refluxed into the circulation in these dogs. In the present study, total cholic acid to chenodeoxycholic acid (C:CDC) ratio increased to 15.5-22.3 at three days post bile duct ligation and after the day 14, the C:CDC ratio decreased to its pre-ligation value or below. In contrast, the glycine conjugated to taurine conjugated bile acids (G:T) ratio did not change. Therefore, at this time, the G:T ratio would not be usable as an indicator of liver disease in dogs while it may be possible to use the C:CDC ratio.

Evaluation of serum fructosamine concentration as an index of blood glucose control in cats with diabetes mellitus.

Fructosamine, a glycated serum protein, was evaluated as an index of glycemic control in normal and diabetic cats. Fructosamine was determined manually by use of a modification of an automated method. The within-run precision was 2.4 to 3.2%, and the day-to-day precision was 2.7 to 3.1%. Fructosamine was found to be stable in serum samples stored for 1 week at 4 C and for 2 weeks at -20 C. The reference range for serum fructosamine concentration in 31 clinically normal colony cats was 2.19 to 3.47 mmol/L (mean, 2.83 +/- 0.32 mmol/L). In 27 samples from 16 cats with poorly controlled diabetes mellitus, the range for fructosamine concentration was 3.04 to 8.83 mmol/L (mean, 5.93 +/- 1.35 mmol/L). Fructosamine concentration was directly and highly correlated to blood glucose concentration. Fructosamine concentration also remained high in consort with increased blood glucose concentration in cats with poorly controlled diabetes mellitus over extended periods. It is concluded that measurement of serum fructosamine concentration can be a valuable adjunct to blood glucose monitoring to evaluate glycemic control in diabetic cats. The question of whether fructosamine can replace glucose for monitoring control of diabetes mellitus requires further study.

Relation of fructosamine to serum protein, albumin, and glucose concentrations in healthy and diabetic dogs.

The relation of the glycated serum protein, fructosamine, to serum protein, albumin, and glucose concentrations was examined in healthy dogs, dogs with hypo- or hyperproteinemia, and diabetic dogs. Fructosamine was determined by use of an adaptation of an automated kit method. The reference range for fructosamine in a composite group of control dogs was found to be 1.7 to 3.38 mmol/L (mean +/- SD, 2.54 +/- 0.42 mmol/L). Fructosamine was not correlated to serum total protein, but was highly correlated to albumin in dogs with hypoalbuminemia. To normalize the data with respect to albumin, it is suggested that the lower limit of the reference range for albumin concentration (2.5 g/dl) be used for adjustment of fructosamine concentration and only in hypoalbuminemic dogs. In 6 hyperglycemic diabetic dogs, fructosamine concentration was well above the reference range. It is concluded that although fructosamine may be a potentially useful guide to assess the average blood glucose concentration over the preceding few days in dogs, further study is required to establish its value as a guide to glucose control in diabetic dogs.

Bile acid fractionations by high-performance liquid chromatography in equine liver disease.

Serum bile acids were fractionated by high-performance liquid chromatography (HPLC) in 13 control and 8 cases of liver disease in horses. The severity and type of liver injury was determined by histopathological examination of biopsy and/or necropsy specimens. The total serum bile acids (tSBA) were determined in these horses by an enzymatic method (SBA-EA) and by summation of the bile acids (SBA-LC) as fractionated by the HPLC. The SBA-LC were generally higher than the SBA-EA in both the controls and liver disease and they did not parallel each other. The primary bile acids, total cholates and total chenodeoxycholates accounted for most of the tSBA increases in liver disease. There was a shift in profile from taurocholate to free (unconjugated) cholate in direct relation to the severity of the liver injury. Among the secondary bile acids, total deoxycholates and total taurodeoxycholates increased at random. The pattern of the SBA profile in relation to the severity of the liver disease suggested that hepatocellular excretion is the most sensitive step in the enterohepatic circulation of the bile acids.

Studies on the fatty acid composition of intramuscular lipids of cattle, pigs and birds.

The fatty acid composition of the intramuscular lipids of cattle, pigs and birds were determined relative to breed and feeding regime. The cattle included Yellow Cattle, Hereford and Japanese Black; pigs included Wild-boar, Touyuens and Yorkshires; the birds were Wild-birds, Jungle-fowl and broilers. The pen fed animals such as Japanese Black cattle and Yorkshire pigs had a higher amounts of oleic acid, palmitic acid and palmitoleic acid. On the other hand, wild or pasture fed animals such as the Herefords, Wild-boars and Touyuens had higher amounts of omega-3 fatty acids such as alpha-linolenic acid, icosapentaenoic acid and omega-6 fatty acids such as linoleic acid and arachidonic acid. Among Wild-fowl, open-yard fed birds or broilers, there was no difference in fatty acid composition. It is suggested the meat of pasture fed or wild fed animals such as Herefords, Yellow Cattle and Wild-boar is better for health than meat from pen fed animals.

Serum bile acid composition of the dog, cow, horse and human.

The fractionation of serum bile acids was performed in the dog, cow, horse, and human by high performance liquid chromatography equipped with an immobilized 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) column. There were significant differences in the bile acid compositions, conjugation patterns and quantities of each bile acid among these animals. Cholic acid was the major primary bile acid in the dog and cow, which constituted 62.9% and 83.5%, respectively, whereas chenodeoxycholic acid was the major acid in the horse and human, which constituted 68.4% and 46.3%, respectively. Taurine conjugates were predominant in the dog and horse, which constituted 94.4% and 85.3%, respectively, whereas glycine conjugates were predominant in the cow and human, which constituted 31.0% and 49.4%, respectively. Although there were several unidentified peaks, it was confirmed that they had a hydroxy group at the C-3 alpha position by chromatographing the samples without the 3 alpha-HSD column.

Animal models of inherited hematologic disease.

Inherited or acquired hematologic disease is the most prevalent of all human disease when we include the hematologic disorders which are secondary to disease of other systems. It follows that the study of the fundamental mechanisms of the disease processes affecting the hematopoietic system is of prime importance and much remains to be done when one considers that in only 25% of ail hemolytic anemias is the fundamental cause eventually discovered [150]. In the current climate of societal pressures on experimental animal research, animals with spontaneous inherited disease mimicking diseases of the various physiological systems assume proportionately greater importance. These animal models have been extremely valuable in the study of fundamental questions of molecular genetics, metabolic aberrations of the cell and its membrane, synthetic mechanisms of the cell as well as clinical questions of disease manifestations, pathogenetic mechanisms and management. Exploration of differences between normal animal species offer a secondary avenue of investigation into these same fundamental questions. New animal models are being uncovered constantly and this augurs well for the future of biomedical research and the ultimate benefit to humankind and to animals in their own right.

Total serum bile acids and the bile acid profile as tests of liver function.

Total serum bile acid assay for the evaluation of liver function has been available for many years but its application has been limited primarily by factors such as methodology, equipment and cost. New and improved methods for bile acid assay such as the radioimmunoassay or the hydroxysteroid dehydrogenase techniques have brought the assay for bile acids into the realm of the clinical laboratory. The efficacy of bile acids for clinical diagnostic use in the evaluation of liver function has not been firmly established. Newer methods using high pressure liquid chromatography to develop a profile of the different bile acids may clarify its usefulness and define its role among the many available tests of liver function in animals.

Pathogenesis of Trypanosoma brucei infection in deer mice (Peromyscus maniculatus). Ultrastructural pathology of the spleen, liver, heart, and kidney.

Trypanosoma brucei EATRO 110 infection of the deer mice (Peromyscus maniculatus) produced moderate to marked lesions in the spleen, liver, heart, and kidney seven to ten weeks after infection. Splenic lesions consisted of marked splenomegaly, with infected spleens weighing 25.9 times control spleens. Transmission electron microscopy of the sinuses and Billroth's cords of the splenic red pulp demonstrated an increased cellularity with greater contact between cells due partly to proliferation of macrophages, transformed lymphocytes and plasma cells and partly to accelerated erythropoiesis with increases in the numbers of rubricytes and reticulocytes. Erythrocytes also were present in large numbers, and erythroclasis was accelerated. Hepatic lesions consisted of necrosis of few hepatocytes, proliferation and hypertrophy of Kupffer's cells which exhibited increased phagocytosis--particularly of erythrocytes, as well as perivascular cuffs consisting of lymphocytes, plasma cells and macrophages. Myocarditis was marked and was characterized by degeneration of myocardial fibers with decreases in mitochondrial size and myofibril contents and fragmentation of some degenerating fibers, and was accompanied by accumulation of inflammatory cells including lymphocytes, transformed lymphocytes, plasma cells, and macrophages between the myocardial fibers. Renal lesions consisted of severe glomerulonephritis characterized by deposition of electron dense material along the basement membrane and in the mesangium of the glomerular tufts, and less frequently beneath the basement membrane and visceral epithelium of the Bowman's capsule and within the peritubular vessels. Neutrophils with fewer macrophages and lymphocytes invaded the glomeruli.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenesis of Trypanosoma brucei infection in deer mice (Peromyscus maniculatus). Light and electron microscopic study of testicular lesions.

The results of light and electron microscopic studies demonstrated that Trypanosoma brucei infection produced marked testicular degeneration in deer mice (Peromyscus maniculatus) with highly significant (p less than 0.001) decreases in testicular weight, seminiferous tubular diameter, and epithelial thickness. Lesions in seminiferous tubules consisted of necrosis of spermatids, spermatocytes, and sometimes the spermatogonia. Sertoli's cells had marked vacuolation and accumulation of phagocytic material. Orchitis was present in most infected mice, particularly those with severe seminiferous tubular degeneration. There was marked folding of the basal laminae of the seminiferous tubule and myoid layer, and a consistent increase in the layers of the basal laminae of the seminiferous tubule. Trypanosomes were present in the intertubular tissues of seminiferous tubules, and they occasionally crossed the myoid layer but never the basal lamina of seminiferous tubules. Inflammatory and other cells in the interstitium consisted of lymphocytes (35.2%), Leydig's cells (25.1%), macrophages (18.1%), plasma cells (12.3%), neutrophils (5.6%), eosinophils (3.2%), and mast cells (0.5%). Inflammatory cells including lymphocytes (51.6%), macrophages (43.9%), plasma cells (3.0%), and eosinophils (1.5%) occasionally breached the myoid layer and occupied the space between it and the basal lamina of the seminiferous tubule. Leydig's cells usually existed in clusters, had decreased mitochondrial size and secretory granules, and folding of the nuclear membrane.

Diabetes mellitus in dogs: relationship of obesity to glucose tolerance and insulin response.

The IV glucose-tolerance test was performed in 71 diabetic dogs (fasting glycemia greater than 6.70 mmol/L) and in 20 healthy dogs. All diabetic dogs were characterized by various degrees of glucose intolerance as expressed by an abnormal glucose disappearance coefficient. On the basis of the fasting plasma insulin concentration (Io), insulin peak response (IPR), the insulinogenic index (delta I/delta G), and the total insulin secretion (TIS), the diabetic dogs were classified, as follows: Type I dogs (n = 32) which had the severe clinical signs of diabetes and an absence of certain diagnostic responses: Io, IPR, delta I/delta G, and TIS. Type II dogs (n = 15) which also had marked diabetic signs and an absence of IPR, delta I/delta G, and TIS responses. The dogs were further subdivided into obese and nonobese groups; the Io was within acceptable limits in the nonobese group (n = 8), but was markedly increased in the obese group (n = 7). Type III dogs (n = 24) had no diabetic signs and a fasting plasma glucose less than 12 mmol/L. They were also subdivided into obese and nonobese groups. The nonobese dogs (n = 13) had Io values within acceptable limits and decreased IPR, delta I/delta G, and TIS. In contrast, the obese dogs had increased Io, IPR, delta I/delta G, and TIS. Statistical analyses indicated that the TIS and IO were highly significant linear functions of obesity.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathogenesis of Trypanosoma brucei infection in deer mice (Peromyscus maniculatus). V. Macrophage ultrastructure and function.

Macrophage numbers increased in the spleen, liver, testes, heart, and kidney of deer mice infected for seven to ten weeks with Trypanosoma brucei EATRO 110. The macrophages were activated as indicated by their increased size and significant increases in numbers of cell organelles including profiles of rough endoplasmic reticulum (which also increased in length), mitochondria, primary and secondary lysosomes, bundles of Golgi's apparatus, and free lysosomes compared to macrophages from control mice. Some macrophages representing epithelioid cells have even greater numbers of organelles than the activated macrophages and had interdigitation in some locations, such as the heart, but with minimal phagocytic activity. These epithelioid cells were present in the kidney, testes, and particularly in the heart of infected mice. Few cardiac macrophages had finely granular deposits on their nuclear membrane. The activated macrophages had enhanced phagocytosis of trypanosomes, red blood cells, neutrophils, eosinophils, lymphocytes, and plasma cells. In addition to phagocytosis, another probable consequence of macrophage activation may be depression of lymphocyte function. Phagocytosis of trypanosomes by neutrophils also was encountered occasionally.

A pharmacokinetic study of digoxin in the horse.

Digoxin was administered orally and intravenously to seven healthy adult mares and geldings in two separate trials. At a dose of 44 microgram digoxin/kg body weight, the oral study was characterized by an absorption phase with a mean (+/- 1 standard deviation) peak serum digoxin concentration of 2.21 ng/ml (+/- 0.45) at a mean of 2.29 h (+/- 1.52) after administration. A second rise in serum digoxin concentration started about 6-8 h after administration and extended to about 20 h after administration. The mean bioavailability (F) was 23.38% (+/- 5.96). At a dose of 22 microgram digoxin/kg body weight, the intravenous study was characterized by a two-compartment model with the following mean pharmacokinetic measurements: distribution rate constant (alpha), 1.391 h-1 (+/- 0.1909); zero-time serum digoxin concentration determined from the distribution phase (A), 21.247 ng/ml (+/- 5.6614); elimination rate constant (beta), 0.0409 h-1 (+/- 0.0069); zero-time serum digoxin concentration determined from the elimination phase (B), 3.82 ng/ml (+/- 0.433); apparent specific volume of distribution uncorrected for protein binding (Vd beta), 5.003 l/kg (+/- 0.5177). The mean beta corresponded to a biological half-life (T1/2 beta) of 16.9 h. Based upon results of this study, theoretically achievable steady-state serum digoxin concentrations were calculated for maintenance doses given by oral and intravenous routes of administration with appropriate two-compartment, multiple-dose formulae. Loading doses were also calculated for each route. It is the opinion of the authors that the oral route of administration of digoxin is effective in the horse and may preclude the potential risks posed by the high serum digoxin concentrations immediately following intravenous administration.

Experimental diabetes and platelet aggregation in the rat.

Alloxan-induced diabetes and platelet aggregation were studied in male Sprague-Dawley rats. Platelets from diabetic rats receiving insulin (one unit protamine-zinc insulin/100 g BW) were consistently more responsive to aggregating agents (ADP, thrombin) than platelets from control rats (with or without insulin administration). Also, serotonin release from platelets was consistently greater in diabetic compared to control rats following thrombin-stimulated platelet aggregation.

Pathogenesis of Trypanosoma brucei infection in deer mice (Peromyscus maniculatus): hematologic, erythrocyte biochemical, and iron metabolic aspects.

Trypanosoma brucei EATRO 110 infection in deer mice (Peromyscus maniculatus) produced anemia in 15 of 42 mice between postinoculation days 14 and 70. The infected anemic (IA) mice had significantly higher reticulocyte counts (P less than 0.025), spleen (P less than 0.001) and liver (P less than 0.005) weights, and higher parasitemia than did infected nonanemic (INA) mice. gamma-Globulin concentrations of infected mice were markedly increased, and values for INA mice were 10% higher than values for IA mice. Erythrocyte hexokinase, glucose-6-phosphate dehydrogenase, glutathione peroxidase, glutathione reductase, and pyruvate kinase activities were increased in infected mice, whereas phosphofructokinase was only slightly decreased in infected mice. Seemingly, development of anemia was not related to defects in erythrocyte metabolism. Serum iron values of infected mice were similar to those of controls. Storage iron (hemosiderin and ferritin) concentrations were increased in the spleen and to a lesser extent in the liver. The activity of superoxide dismutase, an enzyme that favors conversion of easily mobilized soluble ferritin to poorly mobilized insoluble hemosiderin, was decreased per unit weight of the enlarged spleen, although total activity was increased. The superoxide dismutase activity per unit weight of liver was not altered in infected mice although total liver activities were increased. These findings, as well as the marked reticulocytosis, indicate that lack of iron supply does not have a part in precipitating the anemia of T brucei infection. Leukocytosis was present in infected animals and was associated with lymphocytosis, eosinopenia, basophilia, and monocytosis; these changes were more marked in IA than in INA mice.

Pathogenesis of Trypanosoma brucei infection in deer mice (Peromyscus maniculatus): light and electron microscopic studies on erythrocyte pathologic changes and phagocytosis.

Light microscopic and scanning and transmission electron microscopic studies demonstrated that Trypanosoma brucei EATRO 110 produced several alterations in RBC structure including microspherocytes, schistocytosis, vacuolation, doughnut-cell formation, and keratocytosis. Mature RBC and reticulocytes were constantly observed to adhere firmly to trypanosomes in heart blood and in blood vessels of the testes, heart, liver, and kidney, as well as in the sinuses and pulp cords of the spleen. Adhesion of RBC to trypanosomes was also observed by light microscopy in thin blood films. Except for a few platelets that adhered to trypanosomes, other blood cells were not involved. Minute pores were sometimes observed on the RBC membrane at the point of adhesion to the trypanosome, but effects were not seen on the parasite. Erythrophagocytosis was marked in the spleen and to a lesser extent in the liver; mature RBC, as well as reticulocytes, were engulfed. Erythrophagocytosis was presumed to arise from the mechanical injury to RBC, the damage caused by the adhesion phenomenon and the hyperactivity of the enormously enlarged spleen.