Endotoxin-induced neutrophilic alveolitis and macrophage chemotaxin production in sheep.

The mechanism(s) responsible for endotoxin-induced pulmonary leukostasis has not yet been elucidated. We studied ten unanesthetized sheep by performing serial bronchoalveolar lavages (BAL) before and after infusing Escherichia coli endotoxin to determine whether or not neutrophils appeared in the airways and whether or not endotoxemia stimulated alveolar macrophages to produce neutrophil chemotactic activity. The absolute number and percentage of neutrophils recoverable by BAL increased significantly at 24 hours after infusion of endotoxin.

Corticosteroids prevent acute lung dysfunction caused by thoracic irradiation in unanesthetized sheep.

We sought to determine the effect of corticosteroid therapy in a new acute model of oxidant lung injury, thoracic irradiation in awake sheep. Sheep were irradiated with 1,500 rads to the whole chest except for blocking the heart and adjacent ventral lung. Seven experimental sheep were given methylprednisolone (1 g intravenously every 6 h for four doses) and thoracic irradiation; control sheep received only irradiation.

Thromboxane receptor-mediated bronchial and hemodynamic responses in ovine endotoxemia.

The role of thromboxane A2 in sheep endotoxemia, an animal model of the adult respiratory distress syndrome, was investigated by a combined biochemical and pharmacological approach. Endogenous thromboxane biosynthesis was assessed by gas chromatographic-mass spectrometric analysis of urinary (thromboxane B2, 2,3-dinor-thromboxane B2) and plasma (11-dehydrothromboxane B2) metabolites that demonstrated a significant stimulation by endotoxin. The functional relevance of thromboxane A2 was probed with a specific thromboxane-prostaglandin endoperoxide receptor antagonist, SQ 29548.

Acute effects of thoracic irradiation on lung function and structure in awake sheep.

To investigate the acute physiological and structural changes after lung irradiation, the effects of whole-lung irradiation were investigated in fourteen sheep. Ten sheep were prepared with vascular and chronic lung lymph catheters, then a week later were given 1,500 rad whole-lung radiation and monitored for 2 days. Four sheep were given the same dose of radiation and were killed 4 h later for structural studies.