Effect of amprolium on acute sarcocystosis in experimentally infected calves

Twelve calves were used to determine whether treatment with amprolium affected the severity of experimental Sarcocystis fusiformis infections. In each of 2 experiments, 2 calves received an oral dose of amprolium at 100 mg/kg of body weight for 30 days, 2 calves were similarly inoculated but received no medication, and 2 calves served as uninoculated, unmedicated controls. Data from overall weight gains, packed cell volume, body temperature, postmortem and histological examinations, and serum enzyme levels indicate that amprolium reduced the severity of experimental sarcocystosis.

Experimentally induced sarcocystis infection in calves: pathology

Calves fed sporocysts of Sarcocystis isolated from the feces of dogs and coyotes became anorectic, lost weight, and became anemic and prostrate, and died. The most severe pathologic changes occurred between 26 and 33 days after infection; schizonts were found throughout the body. Schizonts were not found after this time. Sarcocytis cysts were in skeletal and cardiac muscles between 33 and 54 days. Necropsy revealed lymphadenopathy, paleness of the mucous membranes and visceral organs, ascites, hydrothorax, hydropericardium, and serous atrophy of fat. Ecchymotic or petechial hemorrhage was in heart, brain, serosa of the alimentary tract, and urinary bladder. Microscopic changes observed in nearly all calves consisted of hemorrhage, mononuclear cell (primarily lymphocytic) infiltration and edema in heart, brain, liver, lung, kidney, and striated muscle. Necrotizing myocarditis with dystrophic calcification of the striated muscle and fat, as well as nonsuppurative inflammation of meninges and glial nodules in the brain, was observed in several calves.

Sarcocystis fusiformis infection in the coyote (Canis latrans)

Of 150 fecal samples from coyotes from northern Utah and southern Idaho, 21 contained coccidian sporocysts. These were found singly, contained four sporozoites and a granular residuum, and averaged 16.9 x 10.9 mum in size. None of four lambs inoculated with these sporocysts showed clinical signs of disease, and no parasites were found in their tissues. One calf inoculated with 135,000 sporocysts and another inoculated with 720,000 sporocysts eventually became unable to rise from recumbency. One was killed after 43 days; the other died at 50 days. Both calves had a mild mononuclear cell infiltration into the connective tissue adjacent to vessels in the heart, other striated muscles, kidney, and liver, and a moderate lymphoid hyperplasia in the spleen and lymph nodes. Schizonts were observed in a lymph node, and young sarcocysts were observed in skeletal and cardiac muscles. Four coyotes fed bovine heart infected with Sarcocystis passed sporulated sporocysts in their feces that were indistinguishable from those in the fecal samples from Utah and Idaho.

Experimentally induced infection of dogs, cats, and nonhuman primates with Ehrlichia equi, etiologic agent of equine ehrlichiosis

Dogs (German Shepherd Dogs and Beagles), cates, rhesus macaques (Macaca mulatta), and baboons (Papio anubis) were inoculated with Whrlichia equi, the etiologic agent of equine ehrlichiosis. Within 3 to 7 days after inoculation, morulae were observed in the eosinophils of cats, neurtrophils of macaques and baboons, and in both neutrophils and eosinophils of dogs. The severe disease produced in horses by this agent was not a feature of E equi infection in dogs, cats, macaques, and baboons. However, a susceptible horse, inoculated with the pooled blood of 2 infected macaques, developed severe clinical signs of equine ehrlichiosis. Infection with E equi did not alter the susceptibiltiy of dogs to infection with Ehrlichia canis and did not prevent development of signs of disease resulting from this infection. The broad experimental host range from this infection. The broad experimental host range of E equi distinguishes it from other ehrlichial agents which are characterized by a rather narrow host range. The susceptibiltiy of nonhuman primates to infection with E equi provides a basis for consideration of the potential transmission of ehrlichial agents to man.

Increase in fibrinogen and fibrin-related antigen in human serum due to in vitro lysis of fibrin by thrombin

In vitro lysis of fibrin, as indicated by increased fibrinogen-fibrin-related antigen (FR-antigen) in serum is usually seen when whole blood, or plasma, or highly purified fibrinogen prepared by several different procedures is clotted and kept at temperatures above 0 degrees C. This increase is both time and temperature dependent, occurs despite the addition of various plasmin and cathepsin inhibitors, and is probably caused by thrombin evolved during clotting and/or added in vitro. In these experiments, the FR-antigen was measured by a sensitive, reproducible hemagglutination inhibition immunoassay adapted to the AutoAnalyzer. Serum from whole blood contained more than serum from plasma, and fibrin rather than fibrinogen proved to be essential for the in vitro lysis. The phenomenon was also caused by Arvin or Reptilase, suggesting that splitting of one or more arginine or lysine bonds in fibrin may be at least partially responsible. To obtain minimal levels of FR-antigen (< 0.5 mug/ml), plasma is clotted for 4 hr at 0 degrees C with 1.0-5.0 U/ml thrombin, CaCl(2) (0.0125 mole/liter), and epsilon aminocaproic acid (0.05 mole/liter). Slightly higher levels, probably adequate for clinical diagnosis, are obtained by 10-30 min clotting at room temperature. Since endogenous and/or exogenous thrombin is essential for the collection of serum FR-antigen, all the FR-antigen found in normal serum probably results from an irreducible amount of in vitro lysis rather than from continuous intravascular clotting and fibrinolysis.

Fibrin degradation products

Images

Partial purification and properties of a plasminogen activator from human erythrocytes

The lysis time of euglobulin clots made with whole blood (plasma and red cells) was very much shorter than that of clots made with plasma alone, indicating a fibrinolytic component in red cells. A plasminogen activator was found in the stroma-free hemolysate, and proteolytic activity was found in the stromal fraction. The plasminogen activator, purified by using diethylaminoethyl-cellulose (DEAE-cellulose) in a batch procedure followed by column chromatography, was called erythrokinase (EK). On preliminary characterization, EK appears to activate human and bovine plasminogen in a manner similar to urokinase (UK), as determined by fibrinolytic and caseinolytic assays. The two enzymes can be separated by DEAE chromatography and acrylamide-gel electrophoresis, however, and they hydrolyze acetyl-L-lysine methyl ester and benzoyl arginine methyl ester at different rates.