Nephrogenic diabetes insipidus in sibling colts.

Nephrogenic diabetes insipidus was diagnosed in two full sibling Thoroughbred colts. Each colt had a history of excessive urination. Extreme polydipsia (greater than 80 L per day) was documented in both colts. Inability to concentrate urine in response to water deprivation, infusion of hypertonic saline, or exogenous vasopressin administration indicated insensitivity of the collecting duct epithelial cells to vasopressin. A diagnosis of nephrogenic diabetes insipidus was further supported by a normal increase in plasma vasopressin concentration after water deprivation in the one colt in which such testing was pursued.

Estrogen-induced bone marrow depression in ferrets.

The administration of estrogen-induced severe bone marrow depression in 9 of 12 ferrets, independent of sex (male, female) or ovariohysterectomy. Resultant pancytopenia was manifested by subcutaneous petechiae, melena, hematomyelia, pale mucous membranes, pale bone marrow, centrilobular hepatic degeneration, hydrometra, and pyometra. These findings are compatible with the naturally occurring estrus-associated anemia seen in female ferrets.

X-ray powder diffraction and microscopic analysis of crystalluria in dogs with ethylene glycol poisoning.

Most of the urinary crystals in 2 dogs intoxicated with ethylene glycol had prismatic (rod-like, hippurate-like), and to a less extent, hemp seed or spindle shapes. Using X-ray powder diffraction and optical analysis, these crystals were identified as calcium oxalate monohydrate. A few crystals of calcium oxalate dihydrate (envelope shape) were also observed in the urine sediment. Their presence was confirmed by the appearance of weak X-ray peaks having interplanar spacings ranging from 0.617 to 0.620 nm, which are thought to correspond to the 200 X-ray reflection of calcium oxalate dihydrate. Thus, the 6-sided hippurate-like crystals in the urine of ethylene glycol-poisoned dogs are actually calcium oxalate monohydrate.

Electrophoretic protein analysis in the conditioned captive wild coyote, Canis latrans.

Total protein, albumin and serum protein values were determined on 19 male and 14 female captive, vaccinated, wild coyotes. Male coyotes had significantly higher total protein, alpha 1 and alpha 2 globulin levels than female coyotes. Captive, wild coyotes had lower values for total protein, albumin and beta globulins, and higher values for alpha 2 and gamma globulins than similar values for laboratory dogs. Albumin values determined by bromcresol green were slightly higher than values derived by electrophoresis. This difference was non-significant.

Hypercalcemia and hypophosphatemia in a mare with renal insufficiency.

An 11-year-old mare with polyuria, polydipsia, and azotemia was found to be hypercalcemic and hypophosphatemic. The concentration of calcium in a single collection of urine was within normal limits, although urinary inorganic phosphate concentration was lower than normal. After a brief period of supportive treatment, the mare died. At necropsy, the kidneys were found to be shrunken and fibrous. Histologically, the lesions were those of glomerulonephritis.

Azotemia in cattle.

Blood biochemical studies were performed on 21 azotemic cattle with various disease conditions. The cattle were greater than or equal to 4 months old. Blood urea nitrogen concentrations ranged from 41 to 346 mg/dl. The azotemia was determined to be of prerenal origin in 10 cattle and of renal or postrenal origin in 11 cattle. The most consistent biochemical finding was that of hypochloremia. Sixteen cattle had lower than normal concentrations of serum calcium, and 15 had serum inorganic phosphorus concentrations greater than normal. In 17 cattle, the serum concentration of inorganic phosphorus was greater than that of calcium. Plasma sodium content was lower than normal in 9 of the 21 cattle, and plasma potassium concentrations were quite variable. Most of the cattle tended to maintain a normal acid-base status or had metabolic alkalosis. It was concluded that evaluation of biochemical data does not make it possible to determine whether azotemia is prerenal, renal, or postrenal in origin.

Urinary indices for differentiation of prerenal azotemia and renal azotemia in horses.

The urine urea nitrogen/plasma urea nitrogen ratio (Uun/Pun), urine creatinine/plasma creatinine ratio (Ucr/Pcr), urine osmolality/plasma osmolality ratio (Uosm/Posm), and fractional excretion of filtered sodium (FENa) were evaluated in 16 horses with acute azotemia to ascertain the significance of each index in the differentiation of prerenal azotemia from renal azotemia. Renal azotemia was diagnosed when renal biopsy or postmortem histologic examination demonstrated evidence of organic renal disease or when azotemia was found in the presence of isosthenuria. The diagnosis of prerenal azotemia was based on the absence of renal histologic lesions or stabilization of blood urea nitrogen and serum creatinine soon after therapy. In 10 horses with renal azotemia, Uun/Pun was 2.1-14.3, Ucr/Pcr was 2.6-37.0, Uosm/Posm was 0.8-1.7, and FENa was 0.08-10.0. In 6 horses with prerenal azotemia, Uun/Pun was 15.2-43.7, Ucr/Pcr was 51.2-241.5, Uosm/Posm was 1.7-3.4, and FENa was 0.02-0.50. The values for each of these indices differed significantly between the 2 groups of horses (P less than 0.05). It was concluded that these indices were of value in the early classification of renal failure in the horse and that this information could be utilized in planning of therapy of acute azotemia in the horse.

Urinary enzyme concentrations in healthy horses.

Urinary concentrations of gamma glutamyl transferase (GGT), alkaline phosphatase (AP), aspartate aminotransferase (AsAT), and alanine aminotransferase (AAT) were measured in 32 healthy horses (16 geldings and 16 females) at the same time on 2 consecutive days. The subjects were divided into 4 ages groups, each comprising 8 horses (4 of each sex). In 10 of the geldings, urine was collected continuously for 72 hours, with catheterized samples being obtained at 0800, 1400 and 2000 hours, and an aliquot of the pooled urine being taken every 24 hours. Urinary enzyme activity was found to be unrelated to serum concentrations of the same enzymes. There was no diurnal variation in the activity of the urinary enzymes. Neither the sex of the horses nor their age influenced urinary enzyme activity regardless of whether it was expressed in absolute terms or in reference to creatinine excretion Normal values of GGT and AP were determined to be 3.3 +/- 3.0 IU/L, (2.5 +/- 3.4 IU/g Cr); and 10.2 +/- 4.0 IU/L (6.7 +/- 3.9 IU/g Cr) respectively. Neither AAT or AsAT were present in detectable levels. The mean urine creatinine concentration of all horses was 1.56 +/- 0.42 g/L with no significant age or sex variation being evident.

A comparison of canine giant cell tumor and giant cell reparative granuloma of bone.

The clinical, radiographic, and pathologic features of a canine giant cell tumor of bone are compared with those of a giant cell reparative granuloma of bone. The giant cell bone tumor usually emerges from the epiphysis of long bones as a rapidly developing lytic bone lesion without periosteal new bone formation. The giant cell reparative bone granuloma originates preferentially in flat bones on the skull and mandible as a result of trauma-associated intraosseous hemorrhage, with new bone formation and sclerosis. Histologically, the neoplastic giant cells are scattered diffusely throughout the tissue, in contrast to the inflammatory giant cells that accumulate at the periphery of hemorrhages or around bone spicules. This peripheral accumulation is accompanied by a prominent collagenous and reticulum stroma. The morphologic and histochemical features of the giant cells can not be used as reliable tools to differentiate these two conditions.

Serum and urinary biochemistry and enzyme changes in ponies with acute renal failure.

Serum and urinary biochemical changes were recorded in 5 ponies in which acute tubular nephrosis had been induced over 5 days with mercuric chloride and potassium dichromate. Serum osmolality, the serum concentrations of urea nitrogen, creatinine, sodium, potassium and chloride, and blood pH and blood gases were measured daily for 14 days or until humane euthanasia was performed. Levels of the same substances were quantitated daily in urine. In addition, routine urinalyses and determination of urinary gamma glutamyl transferase (GGT) activity were performed on each sample. Changes in the values of the urinary variables preceded alterations in the serum value of the same substance by at least one day. The first notable abnormality detected was in urinary GGT activities. These changes occurred up to 6 days before the detection of azotemia. It was concluded that acute equine renal injury could be diagnosed earliest with biochemical testing of urine. Measurement of urinary GGT levels represents a means by which proximal tubular disease in equidae could be diagnosed in its developmental stages.

A reproducible means of studying acute renal failure in the horse.

Acute renal failure was produced in 5 ponies which had received mercuric chloride (0.25 mg/kg) and potassium dichromate (3 mg/kg) intravenously each day for 5 days. Failure was due to acute nephrosis. This was indicated clinically by daily monitoring of the urine output, and B-mode ultrasonography of both kidneys after administering the fifth dose of the chemical agents. Euthanasia was performed after days 14, 9, 5, 8 and 5 respectively in each of the ponies, and the presence of renal disease confirmed by gross and microscopic post mortem examination. The nature of the kidney lesions observed in each animal was consistent, indicating that the induction of renal disease in this manner was reproducible and represented a means by which the pathophysiologic and biochemical development of equine acute renal failure might be studied.

Alterations in calcium, phosphorus and C-terminal parathyroid hormone levels in equine acute renal disease.

The changes in serum and urinary levels of calcium and phosphorus and serum parathyroid hormone (PTH) were studied during controlled, chemically induced, acute renal disease in 4 ponies. There was an initial rise in daily urinary calcium and hydroxyproline excretion in 2 ponies which may have indicated increased bone resorption. Mild hypercalcemia, hypophosphatemia and elevated C-terminal PTH levels were associated with oliguria. Total daily urinary excretion of calcium and phosphorus decreased as oliguria developed. The levels of C-terminal PTH were increased in all four animals. This appears to have been related to their diminished renal function in that C-terminal fragments of intact PTH (which require functioning kidneys in order to be cleared) were probably being accumulated. Although there was no evidence with regard to an actual increase in PTH secretion, prolongation of intact PTH half-life due to renal tubular damage may have contributed to the development of hypercalcemia.