The hematologic and pathologic effects of orally administered L-tryptophan and indoleactic acid and of L-tryptophan administered IV were studied in ponies. Sixteen adult Shetland ponies were allotted into 4 experimental groups. Group 1 consisted of 5 ponies (1-5) given 0.6 g of tryptophan/kg of body weight in a water slurry via stomach tube. Group 2 included 4 ponies (6-9) given 0.35 g of tryptophan/kg orally. Group-3 ponies (10-13) were given 0.35 g of indoleacetic acid/kg orally. Group 4 consisted of 3 ponies (14-16) given a single 4-hour IV infusion of 0.1 g of tryptophan/kg. Restlessness, increased respiratory rate, hemolysis, and hemoglobinuria were detected in 4 of the 5 group-1 ponies. Only pony 7 in group 2 developed hemolysis, hemoglobinuria, and a significant increase in respiratory rate. Renal pathologic lesions, consistent with hemoglobinuric nephrosis, were seen in ponies 2, 4, 5, and 7. Bronchiolar degeneration was evident in 4 of 9 ponies given tryptophan orally. The importance of these respiratory lesions was unknown. Clinical or pathologic abnormalities were not noticed in the ponies of groups 3 and 4. Mean plasma tryptophan values increased significantly in groups 1 and 2 at 6 hours after dosing. A second peak of tryptophan was detected in both groups at 12 hours. Values returned to predose values by 48 hours. Plasma indole and 3-methylindole concentrations were detectable in only 2 ponies (4 and 7). In vitro incubations of cecal fluid from ponies 6, 8, and 9 yielded a percentage conversion of tryptophan to indole of 16.75%, 5.84%, and 7.96%, respectively. 3-Methylindole was not produced. These results suggested that indole was the major metabolite of orally administered tryptophan in these ponies.

The respiratory, renal, hematologic, and serum biochemical effects of hypertonic saline solution (HSS) treatment were examined in 12 endotoxic, pentobarbital-anesthetized calves (8 to 20 days old). Escherichia coli endotoxin (055:B5) was infused IV at a rate of 0.1 microgram/kg of body weight over 30 minutes. Endotoxin induced severe respiratory effects, with marked hypoxemia and increases in arterial-alveolar O2 gradient (P[A-a]O2), physiologic shunt fraction (Qs/Qt), and physiologic dead space to tidal volume ratio (Vd/Vt). Oxygen consumption was decreased, despite an increase in the systemic O2 extraction ratio. Peak effects were observed at the end of endotoxin infusion. The renal response to endotoxemia was characterized by a decrease in free-water reabsorption and osmotic clearance, as well as a decrease in sodium and phosphorus excretion. Endotoxemia induced leukopenia, thrombocytopenia, hyperphosphatemia, hypoglycemia, acidemia, and increased serum alkaline phosphatase concentrations. Calves were treated with HSS (2,400 mosm/L of NaCl, 4 ml/kg, n = 4) or an equivalent sodium load of isotonic saline solution (ISS; 300 mosm/L of NaCl, 32 ml/kg, n = 4) 90 minutes after the end of endotoxin administration. Both solutions were infused over a 4- to 6-minute period. A control group (n = 4) was not treated. Infusion of HSS or ISS failed to induce a significant change in PaO2, P(A-a)O2, (Qs/Qt), (Vd/Vt), or oxygen consumption. Both solutions increased systemic oxygen delivery to above preendotoxin values. Hypertonic saline infusion induced significant (P < 0.05) increases in serum Na and Cl concentrations and osmolality, whereas ISS induced a significant increase in serum Cl concentration and a significant decrease in serum phosphorus concentration. Both HSS and ISS reversed the endotoxin-induced changes in renal function, with increases in free water reabsorption and osmotic clearance, as well as increases in sodium and phosphorus excretion. Sodium retention was greater following HSS administration. On the basis of these findings, hypertonic saline solutions can be rapidly and safely administered to endotoxic calves.

Hematologic reference values were determined for a captive population of 11 Mexican wolves (Canis lupus baileyi). Wolf pups from 4 to 24 weeks old had progressive age-related increases in PCV, hemoglobin concentration, mean cell volume, and RBC counts similar to those seen in domestic dog pups (C familiaris). Hematologic indices in wolves older than 24 weeks were comparable to those of the adult domestic dog; however, PCV, hemoglobin concentration, and RBC counts were higher.