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Arginase induction was reported in several inflammatory lung diseases, suggesting that this may be a common feature underlying the pathophysiology of such diseases. As little is known regarding arginase expression in silicosis, the induction and cellular localization of arginase were elucidated in lungs of Sprague-Dawley rats 24 h following exposure to varying doses of silica by intratracheal instillation. Arginase expression was evaluated by activity assay, quantification of arginase I and arginase II mRNA levels using real-time polymerase chain reaction (PCR), and immunohistochemistry. Analyses of cells and fluid obtained by bronchoalveolar lavage (BAL) showed that markers of pulmonary inflammation, tissue damage, activation of alveolar macrophages (AM) and NO production were significantly increased by all silica doses. Arginase activity was increased also in AMs isolated from BAL fluid of silica-treated rats. Silica produced two- and three-fold increases in arginase activity of whole lung at doses of 1 and 5 mg/100 g body weight, respectively. Levels of arginase I mRNA, but not of arginase II mRNA, were similarly elevated. In control lungs, arginase I immunoreactivity was observed only in AMs sparsely dispersed throughout the lung; no inducible nitric oxide synthase (iNOS) immunoreactivity was detected. In silica-treated lungs, arginase I and iNOS were co-expressed in most AMs that were abundantly clustered at inflammatory foci. The rapid induction of arginase I expression in inflammatory lung cells, similar to induction of arginase in other inflammatory lung diseases, implicates elevated arginase activity as a factor in the development of lung damage following exposure to silica. [ABSTRACT FROM AUTHOR]

Unlabelled: The optimal anesthetic technique for outpatient knee arthroscopy remains controversial. In this study, we evaluated surgical operating conditions, patient satisfaction, recovery times, and postoperative analgesic requirements associated with psoas compartment block, general anesthetic, or spinal anesthetic techniques. Sixty patients were randomized to receive a propofol/nitrous oxide/fentanyl general anesthetic, spinal anesthesia with 6 mg of bupivacaine and 15 micro g of fentanyl, or psoas compartment block with 40 mL of 1.5% mepivacaine. All patients received IV ketorolac and intraarticular bupivacaine. The frequency of postanesthesia recovery room admission was 13 (65%) of 20 for patients receiving general anesthesia, compared with 0 of 21 for patients receiving spinal anesthesia and 1 (5%) of 19 for patients receiving psoas block (P < 0.001). The median time from the end of surgery to meeting hospital discharge criteria did not differ across groups (131, 129, and 110 min for general, spinal, and psoas groups, respectively). In the hospital, 45% of general anesthesia patients received opioid analgesics, compared with 14% of spinal anesthesia and 21% of psoas block patients (P = 0.087). There was no difference among groups with respect to the time of first analgesic use or the number of patients requiring opioid analgesia. Pain scores were highest in patients receiving general anesthesia at 30 min (P = 0.032) and at 60, 90, and 120 min (P < 0.001). Patient satisfaction with anesthetic technique (P = 0.025) and pain management (P = 0.009) differed significantly across groups; patients receiving general anesthesia reported lower satisfaction ratings. We conclude that spinal anesthesia or psoas block is superior to general anesthesia for knee arthroscopy when considering resource utilization, patient satisfaction, and postoperative analgesic management., Implications: Outpatient knee arthroscopy may be performed using a variety of anesthetic techniques. We report that spinal anesthesia and psoas compartment block are superior to general anesthesia when considering resource utilization, patient satisfaction, and postoperative analgesic management.