Platelet activating factor as a mediator of equine cell locomotion

Equine polymorphonuclear (PMN) and mononuclear (MN) leucocytes were separated on Percoll gradients and used to study the chemoattractant properties of the polar ether-linked phospholipid, platelet activating factor (PAF). Six concentrations of PAF ranging from 1 ng/ml to 100 g/ml were studied in each of two in vitro assay systems, the agarose microdroplet and a microfilter technique. Very significant (p<0.01) increases in the movement of both PMN and MN cells were obtained with most concentrations of PAF. In two instances there was no apparent concentration-response relationship, although the action of PAF was approximately bell-shaped in two others. The possible significance of these findings for equine inflammatory conditions is discussed.     

Escherichia coli sepsis and endotoxemia in conscious young pigs

In conscious pigs the influence of intravenous infusion of live E. coli (7×10⁸/kg), of the equivalent amount of endotoxin (20 g/kg) or of a high dose of endotoxin (2.5 mg/kg) on the hemodynamic, clinical and pathological parameters and on survival rate was studied. E. coli and endotoxin infusion resulted in pulmonary hypertension, systemic arterial hypotension, a decrease in cardiac output and an increase in heart rate. Clinical signs were characterized by respiratory and nervous disturbances, whereas necropsy revealed hemorrhages and edema in several organs. Although these findings were similar in the three groups, a marked difference in lethality was observed. Infusion of E. coli or of the high dose of endotoxin resulted in a significant mortality, whereas all pigs survived the infusion of the low dose of endotoxin. This suggests that the lethal pathophysiological mechanisms may only become activated when a sufficient amount of endotoxin is released into the circulation.     

Immunophenotype of pulmonary cellular infiltrates in sheep with visceral caseous lymphadenitis

Pulmonary lesions associated with Corynebacterium ovis were analyzed with an indirect immunoperoxidase staining technique using monoclonal antibodies. The predominant cells in abscess walls and surrounding lung parenchyma were large macrophages which expressed major histocompatibility complex (MHC) class II molecules on their surfaces. T lymphocytes were prominent in the same sites in the naturally occurring lesions, and SBU-T4-positive ("helper/inducer") cells were the major subset of lymphocytes (mean T4/T8 ratio = 3.5). B lymphocytes and granulocytes comprised minor populations of infiltrating cells. These results implicate activated macrophages and MHC class II-restricted T lymphocytes in the pathogenesis of established C. ovis infections in sheep.     

Canine von Willebrand's disease. A heterogeneous group of bleeding disorders

The term "von Willebrand's disease," refers to a group of inherited bleeding disorders, all of which are caused by a deficiency of the multimeric plasma glycoprotein, von Willebrand factor. The various forms of canine von Willebrand's disease can be categorized into one of three major types: in type I canine von Willebrand's disease, all sizes of von Willebrand factor multimers can be detected in the plasma; in type II canine von Willebrand's disease, only the smaller von Willebrand factor multimers are found in the plasma (larger multimers are absent); and in type III canine von Willebrand's disease, von Willebrand factor is completely absent from the plasma or present in only trace amounts. Von Willebrand's disease is common in dogs, but some forms of the disease are so mild that they are of questionable clinical significance.     

Bile duct obstruction secondary to chronic pancreatitis in seven dogs

Seven icteric dogs were determined to have bile duct obstruction secondary to chronic pancreatitis. All dogs had histories of intermittent vomiting and diarrhea. Alkaline phosphatase and alanine aminotransferase activities and total bilirubin concentrations were markedly elevated. Diagnosis was based on exploratory laparotomy and histological examination. Each dog had a 3 to 10 cm mass in the body of the pancreas and obstruction of the common bile duct. Three dogs treated with pancreatectomy, gastrojejunostomy, and cholecystojejunostomy died within five weeks. Three dogs treated with conservative surgical procedures were alive at 8, 16, and 26 months postoperatively. One dog was euthanized because of suspected neoplasia. Hepatic enzyme activity and bilirubin levels decreased markedly in the surviving dogs. Histological examination of the pancreatic masses indicated chronic pancreatitis. Hepatic biopsies revealed evidence of cholestasis. Chronic pancreatitis should be included in the differential diagnoses of icterus, bile duct obstruction, and masses in the pancreas.