Adrenal function testing in the cat: the effect of low dose intravenous dexamethasone administration.

The plasma cortisol responses of 11 normal cats to intravenous dexamethasone at a dose rate of 0.01 mg kg-1 whole bodyweight, were evaluated. Mean plasma cortisol concentrations decreased significantly (P less than 0.01) at three hours and eight hours following dexamethasone administration. Results of this study indicate that plasma cortisol levels are significantly decreased for at least eight hours following low dose intravenous dexamethasone administration in normal cats.

Pharmacodynamic response to Ro15-4513 in ethanol intoxicated dogs.

The interaction of Ro15-4513 (5 mg/kg) with ethanol (3 g/kg, 60%w/v bolus) in dogs was investigated. Ro15-4513 challenge 120 minutes after a single ethanol dose had no significant effect on blood ethanol concentration or heart rate. In the same experiment, (1) blood acetaldehyde concentration was elevated to more than double the control value (vehicle only, no Ro15-4513), and (2) systolic blood pressure decreased to less than 60% of control. Further investigation revealed: (1) after Ro15-4513, area under the blood acetaldehyde vs time curve was more than twofold greater (p = 0.0006) than control, and the area under the systolic blood pressure vs time curve was 76% (p = 0.0027) of control. Based on these results, we propose that an inter-relationship exists between Ro15-4513, blood acetaldehyde concentration, and systolic blood pressure in ethanol intoxicated dogs.

Hepatobiliary scintigraphy in the evaluation of feline liver disease.

Hepatobiliary scintigraphy (HBS) was performed in 10 cats with histologically documented hepatobiliary disease. The scintigraphic patterns were classified into one of 5 categories: normal, primary hepatocellular dysfunction, primary intrahepatic cholestasis, mixed hepatocellular and intrahepatic cholestasis, and extrahepatic obstructive patterns. Initial attempts were made to correlate specific disease entities with HBS patterns, but a consistent relationship could not be determined. A correlation between the histological severity of a given hepatic disease and the HBS pattern was made. All cats (n = 5) with a mixed hepatocellular and intrahepatic cholestasis scintigraphic pattern with normal gallbladder function had a histologically severe form of their individual hepatic disease. Three of the 4 cats with an intrahepatic cholestasis pattern and normal hepatocellular and gallbladder function had histologically mild or moderate forms of their individual hepatic diseases. One cat had an extrahepatic obstructive pattern where no radiopharmaceutical was identified in the gallbladder or small intestine by 3 hours postinjection. This study suggests that HBS can be useful in cats with hepatobiliary disease to assess the severity of hepatic dysfunction, and to determine if extrahepatic biliary obstruction is present. Correlation between HBS patterns and specific disease entities such as hepatic lipidosis or cholangitis-cholangiohepatitis syndrome could not be made in this study.

Characterization and treatment of water, electrolyte, and acid-base imbalances of induced urethral obstruction in the cat.

Urethral obstruction induced in adult male cats caused clinical signs identical with those observed in naturally occurring disease. Central nervous system depression, anorexia, dehydration, vomiting, muscle weakness, and hypothermia occurred. Weight loss (due to water loss and catabolism), metabolic acidosis, mild hyponatremia, hyperkalemia, hypermagnesemia, hypocalcemia, hyperphosphatemia, hyperglycemia, azotemia, and hyperproteinemia were also observed. Serum amylase, alkaline phosphatase, and alanine aminotransferase activities were normal. Ten of 13 cats (group 1), with 72 hours' induced obstruction but not treated with parenteral fluids, died either before the obstruction was relieved or within 8 days afterward. Eight cats (group 2) with induced obstruction for 49 to 98 hours developed severe clinical and biochemical alterations. Treatment with a multiple-electrolyte solution, in addition to relief of urethral obstruction, resulted in favorable clinical and biochemical responses. These cats survived and were clinically healthy at 9 to 10 days after relief of obstruction. It was concluded that use of a multiple-electrolyte solution to correct acidosis, restore circulatory volume, and enhance renal excretion of potassium was effective supportive therapy after urethral obstruction was removed.

Plasma, tissue, and urine carnitine concentrations in healthy adult cats and kittens.

Mean carnitine concentrations [( carnitine]) were higher (P less than 0.05) in adult cats than in kittens for skeletal muscle (total and free carnitine), myocardium (free carnitine), and urine (total and free carnitine). The free/total carnitine ratio was lower (P less than 0.05) in kittens than in adults for liver, myocardium, and urine. Carnitine concentrations were similar between genders in kittens, but in adult cats, [carnitine] in plasma (total, free, and esterified carnitine) and liver (total and free carnitine) were higher (P less than 0.05) in female than in male cats. Total and free plasma [carnitine] were correlated to total and free liver [carnitine], respectively. Skeletal muscle [carnitine] was not correlated to plasma [carnitine]. Correlations in [carnitine] between plasma and myocardium, kidney, or urine were inconsistent.

Effect of adrenalectomy in the dog on blood gas tensions and oxygen content.

Arterial and venous blood gas tensions and pH were determined in 8 dogs during a control interval, while adrenal deficient, and following replacement therapy with corticosteroids. Additionally, erythrocyte 2,3-diphosphoglycerate (DPG) values were measured, and oxygen tension (mm of Hg) when hemoglobin is half-saturated with oxygen (P50) values were calculated. Mixed venous oxygen tension (PVO2), but not arterial oxygen tension (Pao2), decreased significantly (P less than 0.001) during adrenal insufficiency. This change was reflected in a significantly decreased (P less than 0.001) venous oxygen content and a significant increase (P less than 0.001) of the arterial-venous oxygen content difference. Other changes during adrenal insufficiency were nonsignificant decreases in DPG and P50 values. Treatment with corticosteroids for 2 to 3 days resulted in a significant (P less than 0.001) increase in DPG concentrations, a significant (P less than 0.025) increase in P50, and a reduction in the arterial-venous oxygen content difference compared with those values found in the adrenal-deficient dog.

Pathophysiologic studies of calves given 3-methylindole intraruminally.

Intraruminal administration of 0.25 g of 3-methylindole (3MI; skatole/kg of body weight) to seven young calves generally caused mild respiratory signs and lesions, accompanied by only slight changes in cardiopulmonary function. Moderate depression, trembling, and irregular respiratory rate were observed between postadministration hours (PAH) 6 and 12. By PAH 24 at this dosage, abnormal clinical signs were not present. Statistically significant (P less than or equal to 0.05) changes observed in blood gas data from the seven calves were a decrease in aortic oxygen tension at PAH 12, increases in free-flowing venous oxygen tension in the intervals between PAH 6 and 12 and between PAH 6 and 24, and an increase in occluded venous oxygen tension at PAH 24. All calves had increases (although generally not statistically significant) in heart rate, cardiac output, cardiac index, stroke volume, and stroke index after 3MI administration. Mean aortic and pulmonary arterial pressure changes were generally small and variable. At necropsy, the lungs of the calves did not collapse when the thorax was opened. Patchy areas of consolidation (0.5 cm in diameter) were scattered throughout the parenchyma. Pulmonary edema or emphysema was not observed grossly. Microscopically, the alveolar septae were irregularly thickened because of edema, infiltration by polymorphonuclear and mononuclear cells, and vascular congestion. Interstitial lesions were patchy in distribution and severity and corresponded to the areas of consolidation observed grossly. Alveolar epithelial hypertrophy and hyperplasia were present, and an occasional focus of alevoli contained fluid of edema. Degeneration of individual hepatocytes was observed in scattered areas of the liver, especially in the periportal areas. It was concluded that differences in 3MI dosage response may exist between young calves and adult cattle in which calves are more resistant to the pulmonary cytotoxicity of 3MI.

Glycosylated albumin and serum protein in diabetic dogs.

Glycosylated albumin and glycosylated protein in serum were measured in 4 well-controlled diabetic dogs, 4 poorly controlled diabetic dogs, and 21 nondiabetic dogs. Concentrations of both glycosylated components in the well-controlled dogs were similar to those in nondiabetic dogs. Serum concentrations of glycosylated albumin and protein in the poorly controlled diabetic dogs were higher (P less than 0.001) than those of the nondiabetic and well-controlled diabetic dogs. Because of the essentially irreversible nature of the glycosylation reaction and the relatively short turnover time of albumin and other serum proteins, measurements of glycosylated serum components may provide an index of glycemia during the preceding days or weeks.

Indocyanine green clearance and ammonia tolerance in partially hepatectomized and hepatic devascularized, anesthetized dogs.

Indocyanine green clearance and ammonia tolerance were measured in anesthetized dogs with 60% hepatectomy, 40% hepatectomy, portacaval shunt, and hepatic artery ligation. With a dose of 0.5 mg of indocyanine green/kg of body weight, plasma clearance of the dye was significantly (P less than 0.001) delayed only in dogs with 60% hepatectomy. Ammonia tolerance was abnormal in dogs in this group, because after they were given a gastric challenge load of an ammonium salt, they had a 5-fold increase in plasma ammonia concentration, compared with a 2.5-fold increase in the control group. Before challenge loading, base-line plasma ammonia concentration was significantly (P less than 0.05) increased within 5 minutes after surgical preparation of the portacaval shunt. After challenge loading the stomach with an ammonium salt, dogs with portacaval shunt had increased plasma ammonia concentration, but the amount was not significantly different from postchallenge-loading values in control dogs. Dogs with 40% hepatectomy and with hepatic artery ligation could not be differentiated from control dogs by indocyanine green clearance or by ammonia tolerance testing. Abnormal tolerance to a challenge gastric load of an ammonium salt or delayed clearance of indocyanine green may indicate marked loss of functional hepatic mass, but normal tolerance or normal dye clearance may not exclude liver disease or dysfunction. Seemingly, base-line plasma ammonia concentration was a sensitive indicator of abnormal portal circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of hepatobiliary scintigraphy in clinically normal cats.

Hepatobiliary scintigraphy provides a noninvasive assessment of hepatobiliary structure and function, and has been used extensively in people. Hepatocellular measurements determined in the cats of this study include cardiac washout (< or = 2 minutes) and time of maximal hepatic activity (< or = 5 minutes) and hepatic washout (< or = 30 minutes). The gallbladder response to synthetic cholecystokinin was determined to be < or = 3 minutes. Additional measurements also were identified. Potential use of hepatobiliary scintigraphy in feline medicine is discussed.

Arterial blood gas and acid-base values in dogs with various diseases and signs of disease.

Results of arterial blood gas and acid-base analysis on initial samples prior to therapy were reviewed for 220 dogs admitted to the University of Georgia Veterinary Teaching Hospital. Acidemia or alkalemia was detected in 61 of 220 dogs (28%). The most common acid-base abnormality was metabolic acidosis (79 of 220 dogs--36%). Primary metabolic acidosis was the acid-base category associated most frequently with the combination of vomiting and diarrhea, dehydration, and the combination of polydipsia and polyuria, whereas normal mean arterial PCO2 and [HCO3-] values and primary metabolic acidosis were detected with equal frequency in vomiting, diarrhea, and cyanosis. Arterial hypoxemia was found most frequently in patients with restrictive respiratory tract disease (restricted lung expansion), lower respiratory tract disease, heartworm disease, and circulatory system disease. Significantly lower (P less than or equal to 0.05) arterial pH and PO2 were detected initially in dogs that eventually died, as compared with dogs that were improved at the time of discharge from the hospital. Mean [HCO3-] values also were lower initially in dogs that eventually died, as compared with those that improved, but the differences were not statistically significant.

Glycosylated hemoglobin in diabetic and nondiabetic dogs.

Glycosylated hemoglobin (HbA1) was measured in 40 nondiabetic hospitalized dogs, 16 clinically normal laboratory colony dogs, and 16 diabetic dogs. Mean HbA1 values (% of total Hb) for the 3 groups were 6.43, 5.62, and 9.63, respectively. The mean values for the 2 nondiabetic groups differed significantly (P less than 0.05), and the mean values for the nondiabetic dogs were significantly lower than the mean value for that of the diabetic dogs (P less than 0.001). Fifteen of 16 diabetic dogs had HbA1 concentrations greater than 7.5%. These results suggested that HbA1 measurement may be valuable for monitoring effectiveness of therapy in canine diabetes mellitus.

Anomalous portosystemic anastomoses associated with chronic hepatic insufficiency in six young dogs.

Chronic hepatic insufficiency due to anomalies of the portal venous system was diagnosed in 6 young dogs. The disorder was characterized by a variety of abnormal central nervous system signs or ascites, or both. Laboratory findings were characteristic of chronic, generalized hepatic dysfunction. The diagnosis was established by angiographic studies of the portal venous system. Of the 6 dogs, 3 died, 1 was euthanatized, and 2 are still alive and require medical management for ascites.

Congenital portacaval shunts in two cats: diagnosis and surgical correction.

Congenital portacaval shunts causing signs of hepatic encephalopathy were diagnosed and surgically corrected in 2 cats. A tentative diagnosis of portacaval shunt in each case was based on history, results of physical examination, and a high venous ammonia concentration. A definitive diagnosis was established by mesenteric portography and by direct visualization of the shunt vessel during surgery.

Complications with non-endoscopic percutaneous gastrostomy in 31 cats and 10 dogs: a retrospective study.

Percutaneous gastrostomy tubes were placed non-endoscopically in 31 cats and 10 dogs using either a rigid insertion tube (n = 13) or an Eld gastrostomy tube applicator (n = 28). Tubes were placed successfully in 38 of the 41 animals and the consequent feeding was of therapeutic benefit to 31 of the animals. Six of 41 died or were euthanased for reasons unrelated to gastrostomy. In four cases (10 per cent), gastrostomy failed with respect to correct tube placement or tube feeding. Overall complications occurred in 18 of 41 animals. Severe procedural complications occurred in two cats; a cardiorespiratory arrest during pharyngeal manipulation and erroneous tube placement through the distal oesophagus. Moderate late complications included peristomal food leakage (n = 2), peristomal abscess (n = 2) and pyloric outflow obstruction by a migrated tube (n = 1). Complications associated with the feeding procedure, nausea and vomiting (n = 3), led to aspiration pneumonia in one case.