Defects in myeloid cell function in Rac2 knockout mice underline the importance of this isoform in activation of NADPH oxidase and cell motility. However, the specific role of Rac1 in neutrophil function has been difficult to assess since deletion of Rac1 results in embryonic lethality in mice. To elucidate the specific role of Rac1 in neutrophils, we generated mice with a conditional Rac1 deficiency restricted to cells of the granulocyte/monocyte lineage. As observed in Rac2-deficient neutrophils, Rac1-deficient neutrophils demonstrated profound defects in inflammatory recruitment in vivo, migration to chemotactic stimuli, and chemoattractant-mediated actin assembly. In contrast, superoxide production is normal in Rac1-deficient neutrophils but markedly diminished in Rac2 null cells. These data demonstrate that although Rac1 and Rac2 are both required for actin-mediated functions, Rac2 is specifically required for activation of the neutrophil NADPH oxidase.
Tuberous sclerosis complex (TSC) is a familial tumor disorder for which there is no effective medical therapy. Disease-causing mutations in the TSC1 or TSC2 gene lead to increased mammalian target of rapamycin (mTOR) kinase activity in the conserved mTOR signaling pathway, which regulates nutrient uptake, cell growth, and protein translation. The normal function of TSC1 and TSC2 gene products is to form a complex that reduces mTOR kinase activity. Thus, mTOR kinase inhibition may be a useful targeted therapeutic approach. Elevated interferon-gamma (IFN-gamma) expression is associated with decreased severity of kidney tumors in TSC patients and mouse models; therefore, IFN-gamma also has therapeutic potential. We studied cohorts of Tsc2+/- mice and a novel mouse model of Tsc2-null tumors in order to evaluate the efficacy of targeted therapy for TSC. We found that treatment with either an mTOR kinase inhibitor (CCI-779, a rapamycin analog) or with IFN-gamma reduced the severity of TSC-related disease without significant toxicity. These results constitute definitive preclinical data that justify proceeding with clinical trials using these agents in selected patients with TSC and related disorders.
Hospital staff and patients agreed that pain, vital signs and tests were top sleep disrupters. However, pain was associated with the greatest objective sleep loss, highlighting the need for proactive screening and management of patient pain to improve sleep in hospitals.
To fully evaluate the cost difference between these procedures, a cost-effectiveness analysis must be performed that incorporates quality-of-life data. Such data would significantly affect assessments of the cost difference between implant and autogenous tissue reconstruction.
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