ABSTRACT:Airway inflammation with mucus overproduction is a distinguishing pathophysiological feature of many chronic respiratory diseases. Phosphodiesterase (PDE) inhibitors have shown anti-inflammatory properties. In the present study, the effect of sildenafil, a potent inhibitor of PDE5 that selectively degrades cyclic guanosine 39,59-monophosphate (cGMP), on acrolein-induced inflammation and mucus production in rat airways was examined.Rats were exposed to acrolein for 14 and 28 days. Sildenafil or distilled saline was administered intragastrically prior to acrolein exposure. Bronchoalveolar lavage fluid (BALF) was acquired for cell count and the detection of pro-inflammatory cytokine levels. Lung tissue was examined for cGMP content, nitric oxide (NO)-metabolite levels, histopathological lesion scores, goblet cell metaplasia and mucin production.The results suggested that sildenafil pretreatment reversed the significant decline of cGMP content in rat lungs induced by acrolein exposure, and suppressed the increase of lung NO metabolites, the BALF leukocyte influx and pro-inflammatory cytokine release. Moreover, sildenafil pretreatment reduced acrolein-induced Muc5ac mucin synthesis at both mRNA and protein levels, and attenuated airway inflammation, as well as epithelial hyperplasia and metaplasia.In conclusion, sildenafil could attenuate airway inflammation and mucus production in the rat model, possibly through the nitric oxide/cyclic guanosine 39,59-monophosphate pathway, and, thus, might have a therapeutic potential for chronic airway diseases.

Laparoscopic intersphincteric resection with a stapled coloanal anastomosis is technically feasible and is less likely to result in anastomotic leakage and stricture formation than a hand-sewn anastomosis.

Within the ladder approximation, the general form of the quark-antiquark interaction kernel, consistent with chiral symmetry, is investigated through the combined use of Ward identities for the axial and vector currents. In the charm and bottom sectors we show that chiral symmetry still plays an important role, through the functional form of the quark-antiquark forces. To maintain the chiral symmetry the scalar, pseudoscalar and tensor terms of the local interaction kernel must appear in a combination consistent with the equation Ks = Kp = −3Kt. Within the validity domain of the ladder approximation, this result is independent of the quark current masses. While the vector and axial parts, Kv and Ka, are not constrained by chiral symmetry, they are needed in order to implement spontaneous chiral-symmetry breaking, since the above terms alone would not do. In addition to the usual spin-spin, spin-orbit and tensor interactions, the existence of a Lorentz-tensor term in the kernel gives rise to a second tensor force which does not appear in previous studies of mesonic spectroscopy.

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Disc storing mechanism driven by hydraulic cylinder is the key component to ensure the deep sea coring. However, clearance is inevitable for assembly in joint of mechanism lead to poor operational characteristics. To ensure design and working reliability, disc storing mechanism driven by hydraulic cylinder for benthic drill with clearance is analyzed from a dynamic view. With piston rod be equivalent to slider, engaging lugs at end of cylinder to revolute joint and contact impact model deal with clearance, the dynamic model of disc storing mechanism driving by piston rod is present. The simulation model for the mechanism with clearance driven by cylinder using Simulink is established and analysis of dynamics is investigated. The simulation results for the case with and without clearance are evaluated under different driving conditions for motion characteristics and driving force. The effect of clearance to disc storing mechanism driven by hydraulic cylinder is found. These supply a lead for moving parameters choosing and a theory basis for key parts designing of the mechanism.