fibrin and Pasteurellosis--Pneumonic

To determine the role of tissue factor (TF) in the coagulation events leading to intra-alveolar fibrin deposition and intravascular thrombosis associated with pneumonic pasteurellosis in cattle.. Healthy 2- to 4-week-old male Holstein calves.. Blood and bronchoalveolar lavage samples were collected before and at 1, 2, 4, and 6 hours after inoculation of saline solution or Pasteurella haemolytica. Total leukocyte count, platelet count, plasma total protein concentration, prothrombin time, and partial thromboplastin time were measured in blood samples. Total nucleated cell count, total protein concentration, and procoagulant activity were measured in bronchoalveolar lavage samples. Additionally, platelet survival in blood platelet accumulation in affected lung tissue, and gross and microscopic lung lesions were determined.. Administration of TF monoclonal antibodies (MAB) TF1-1F7 prevented the decrease in platelet survival and the increase in bronchoalveolar lavage fluid TF-dependent procoagulant activity observed in calves not treated with MAB TF1-1F7 antibody, but did not attenuate the increase in lavage fluid neutrophil numbers and total protein concentration, MAB TF1-1F7 administration reduced the percentage of lung affected by pneumonic lesions from 51.81% to 10.40% and attenuated intra-alveolar deposition of fibrin, neutrophils, and erythrocytes.. Intra-alveolar fibrin deposition and activation of coagulation in cattle with pneumonic pasteurellosis is, at least in part, mediated by TF.. Treatments that neutralize TF activity may attenuate lung injury in cattle with pneumonic pasteurellosis.

Topics: Animals; Antibodies, Monoclonal; Blood Coagulation; Blood Platelets; Bronchoalveolar Lavage Fluid; Cattle; Cattle Diseases; Fibrin; Leukocyte Count; Macrophages, Alveolar; Male; Mannheimia haemolytica; Neutrophils; Pasteurellosis, Pneumonic; Platelet Count; Pulmonary Alveoli; Thromboplastin; Thrombosis

Eighteen male Holstein calves were divided into groups of three and inoculated intratracheally with 5 x 10(9) logarithmic phase or ultraviolet light-killed Pasteurella haemolytica biotype A serotype 1. Serial coagulation profiles were done on one calf from each group during the first 24 hours after inoculation. One calf from each group was necropsied at 4, 12, and 24 hours after inoculation and lesions were characterized with light and transmission electron microscopy. We found that 1) the pulmonary intravascular macrophage may have an important role in the early intravascular inflammatory events; 2) there was morphologic evidence for local initiation of the coagulation cascade in the lung early in the disease process but it was not a consumptive process; and 3) killed-bacteria were capable of causing fibrin exudation, platelet aggregation and alveolar epithelial damage similar to live bacteria, but the degenerative changes in neutrophils, endothelial cells and intravascular fibrin formation that occur with live bacteria were not seen.

Topics: Animals; Blood Coagulation; Capillaries; Cattle; Cattle Diseases; Fibrin; Leukocytes; Lung; Macrophages; Male; Mannheimia haemolytica; Microscopy, Electron; Pasteurellosis, Pneumonic; Platelet Aggregation; Pulmonary Alveoli; Ultraviolet Rays

Experimental pneumonia caused by Pasteurella haemolytica was induced in 2-week-old gnotobiotic (n = 4) and conventional (n = 6) calves by endobronchial inoculation into the right caudal lung lobe of 7.9 x 10(10) +/- 0.6 x 10(10) (mean +/- SD) colony-forming units of P haemolytica in the 6-hour log phase of growth. The calves were studied for 24 hours or less. Regression lines for the relationship between clinical index and time for the gnotobiotic group and conventional group of calves were compared, and the clinical index was found to be significantly (P less than or equal to 0.005) more rapid in the gnotobiotic group. There was also a significant difference in the preinoculation, absolute segmented neutrophil count (P less than or equal to 0.05), and in the total serum protein, albumin, and globulin values (P less than or equal to 0.05). Comparison of the preinoculation and post inoculation blood cell and blood chemical values revealed a significant increase (P less than or equal to 0.05) in the numbers of band neutrophils and fibrinogen in conventional calves, and a significant decrease (P less than or equal to 0.05) in the total WBC count in gnotobiotic calves. Necropsy of both groups of calves revealed a circular to oblong lesion that was congested, edematous, and firm, and which occupied 20% to 100% of the right caudal lung lobe and involved the remaining lung lobes to a more minor degree. When mean lesion scores of the 2 groups of calves were compared, no significant difference (P less than or equal to 0.05) was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Cattle; Cattle Diseases; Female; Fibrin; Germ-Free Life; Lung Diseases; Male; Pasteurella; Pasteurellosis, Pneumonic; Pulmonary Edema; Time Factors