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Dogs, rats, mice, and gerbils were exposed for 6 hours per day, 5 days per week, for periods up to 2 years, to an atmosphere containing a complex mineral oil-base mist at concentrations of 5 and 100 mg/M3. The mass median diameter of the oil droplets was approximately that found in textile plants ( approximately 1.0 mu). In addition, these test atmospheres contained 1000 ppm acetone,an acetate fiber solvent, in order to simulate fiber plant conditions. Evidence of oil mist was detectable within lung macrophages of all species tested and at both concentrations. Only at the higher concentration (100 mg/M3),, in dogs and rats, but not in mice and gerbils, was a retention of oil of such a magnitude so as to result in the development of oil microgranulomas. Rats given a 10-month recovery period following 12 months of exposure did not completely recover from the oil microgranuloma. These results indicate that the presence of typical textile fiber adjuvants in mineral oil and the concurrent presence of 1000 ppm acetone in the atmosphere do not significantly alter the inhalation toxicity of pure white mineral oil mist.

Background: Clinical guidelines recommend MAP maintenance at 85-90 mmHg to optimize spinal cord perfusion post-SCI. Recently, there has been increased interest in spinal cord perfusion pressure as a surrogate marker for spinal cord blood flow. The study aims to determine the congruency of subdural and intramedullary spinal cord pressure measurements at the site of SCI, both rostral and caudal to the epicenter of injury. Methods: Seven Yucatan pigs underwent a T5 to L1 laminectomy with intramedullary (IM) and subdural (SD) pressure sensors placed 2 mm rostral and 2 mm caudal to the epicenter of SCI. A T10 contusion SCI was performed followed by an 8-hour period of monitoring. Axial ultrasound images were captured at the epicenter of injury pre-SCI, post-SCI, and hourly thereafter. Results: Pigs with pre-SCI cord to dural sac ratio (CDSR) of >0.8 exhibited greater occlusion of the subdural space post-SCI with a positive correlation between IM and SD pressure rostral to the injury and a negative correlation caudal to the epicenter. Pigs with pre-SCI CDSR <0.8 exhibited no correlation between IM and SD pressure. Conclusions: Congruency of IM and SD pressure is dependent on compartmentalization of the spinal cord occurring secondary to swelling that occludes the subdural space.