Enhanced proliferation of smooth muscle cells contributes to airway remodeling of bronchial asthma. Recently, statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, have been shown to inhibit proliferation of both vascular and airway smooth muscle cells independently of lowering cholesterol. However, the mechanisms remain to be elucidated. The purpose of this study was to determine molecular processes by which statins inhibit proliferation of human bronchial smooth muscle cells. Simvastatin (0.1-1.0 muM) significantly inhibited cell proliferation and DNA synthesis induced by FBS in a concentration-dependent manner. The inhibitory effects of simvastatin were antagonized by mevalonate and geranylgeranylpyrophosphate, whereas the effects were not affected by squalene and farnesylpyrophosphate. The antiproliferative effects of simvastatin were mimicked by GGTI-286, a geranylgeranyltransferase-I inhibitor, C3 exoenzyme, an inhibitor of Rho, and Y-27632, an inhibitor of Rho-kinase, a target protein of RhoA. Western blot analysis showed that the level of membrane localization of RhoA (active Rho) was markedly increased by FBS, and that the level of active RhoA increased by FBS was reduced by simvastatin. Moreover, the inhibitory effect of simvastatin on FBS-induced RhoA activation was also antagonized by geranylgeranylpyrophosphate, but not by farnesylpyrophosphate. Because these isoprenoids are required for prenylation of small G proteins RhoA and Ras, respectively, the present results demonstrate that an inhibition in airway smooth muscle cell proliferation by simvastatin is due to prevention of geranylgeranylation of RhoA, not farnesylation of Ras. Therefore, statins may have therapeutic potential for prohibiting airway remodeling in bronchial asthma.

In the present study, we investigated whether extracellular sphingosine 1-phosphate (S1P) is involved in airway hyperreactivity in bronchial asthma. The effects of S1P on the response to methacholine was examined in the fura-2-loaded strips of guinea pig tracheal smooth muscle using simultaneous recording of the isometric tension and the ratio of fluorescence intensities at 340 and 380 nm (F 340 /F 380 ). A 15-min pretreatment with S1P (Ͼ100 nM) markedly enhanced methacholineinduced contraction without elevating F 340 /F 380 . This effect of S1P was suppressed in the presence of Y-27632a selective inhibitor of Rho-kinase, in a concentration-dependent manner. Moreover, pretreatment with pertussis toxin caused an inhibition in S1P-induced hyper-reactivity to methacholine in a time-and concentration-dependent manner. In contrast, although S1P-induced Ca 2ϩ mobilization was attenuated by SKF96365 and verapamil, the subsequent response to methacholine was unaffected. A 15-min pretreatment with lower concentrations of S1P (Ͻ100 nM), which is clinically attainable, did not increase methacholine-induced contraction. However, when the incubation was lengthened to 6 h, S1P (Ͻ100 nM) enhanced the subsequent response to methacholine. Next, application of S1P to cultured human bronchial smooth muscle cells increased the proportion of active RhoA (GTP-RhoA) and phosphorylation of myosin phosphatase target subunit 1 (MYPT1). This phosphorylation of MYPT1 was significantly inhibited by application of Y-27632 and by pretreatment with pertussis toxin. Our findings demonstrate that exposure of airway smooth muscle to S1P results in airway hyper-reactivity mediated by Ca 2ϩ sensitization via inactivation of myosin phosphatase, which links G i and RhoA/Rho-kinase processes.

ACE-R J proved to be an accurate cognitive instrument for detecting MCI and mild dementia. Further neuropsychological evaluation is required for the differential diagnosis of dementia subtypes.

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Objectives: To determine whether age differences are present in the human laryngeal thyroarytenoid muscle that would indicate that different normative values would be needed for identifying motor unit abnormalities. Study Design: Twenty-six consecutively recruited healthy subjects between the ages of 21 and 72 years participated in a laryngeal electromyography study. Methods: Bipolar needle electrodes were used to record motor unit action potentials from several locations in the right and left thyroarytenoid muscles of each subject. The duration of a motor unit was measured when at least 10 firings of the same motor unit could be identified. On the average, four units were measured per muscle. Results: In the subjects less than 60 years of age, motor unit duration did not increase significantly with age. However, motor units from subjects greater than 60 years of age had longer durations than those from subjects less than 60 years of age (P < .00005), and 25% of the units measured in subjects greater than 60 years of age had longer durations than any of the units measured in subjects less than 60 years of age. Further, the older subjects differed from each other in their mean unit durations (P < .0001). In subjects less than 60 years of age, significantly longer durations were found for units innervated by the longer, left-side recurrent laryngeal nerve in comparison with the right-side nerve (P ‫؍‬ .005). Conclusions: Different mean and SD values should be used for patients less than and greater than 60 years of age and for the right and left sides, when evaluating motor units in the thyroarytenoid muscles.

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The concentration-inhibition curve for ISO against methacholine in tension was significantly dissociated from the curve for ISO in [Ca2+](i). In ISO-induced relaxation, a reduction in tension was significantly greater than that in [Ca2+](i.) This phenomenon was mimicked by other cAMP-related agents: forskolin and dibutyryl-cAMP. In contrast, the inhibitory action of SKF-96365, a non-selective inhibitor of Ca(2+) channels, was associated with that in [Ca2+](i). In the presence of Rp-cAMPS, an inhibitor of protein kinase A (PKA), ISO caused an equivalent relaxation with less reduction in [Ca2+](i). The effects of ISO were not affected by Y-27632, an inhibitor of Rho-kinase, or by bisindolylmaleimide, an inhibitor of protein kinase C. ISO failed to inhibit contraction elicited by calyculin A, an inhibitor of myosin phosphatase. Conclusion beta-Adrenergic action antagonizes not only Ca2+ mobilization but also Ca2+ sensitization in methacholine-induced contraction. The cAMP/PKA-independent, G(s)-direct action is more potent in Ca(2+)-independent relaxation by beta-agonists than the cAMP/PKA-dependent pathway. Moreover, myosin phosphatase is a fundamentally affected protein in the reduced response to Ca2+ mediated by beta-agonist. Our results may provide evidence that this Ca2+ desensitization is a novel target for a reliever medication using rapid-acting beta-agonists in acute asthma management.