1 7-[2-[4-(2-chlorophenyl)piperazinyl]ethyl]-1,3-dimethylxanthine (KMUP-1) produces tracheal relaxation, intracellular accumulation of cyclic nucleotides, inhibition of phosphodiesterases (PDEs) and activation of K þ channels. 2 KMUP-1 (0.01-100 mM) induced concentration-dependent relaxation responses in guinea-pig epithelium-intact trachea precontracted with carbachol. Relaxation responses were also elicited by the PDE inhibitors theophylline, 3-isobutyl-1-methylxanthine (IBMX), milrinone, rolipram and zaprinast (100 mM), and a K ATP channel opener, levcromakalim. 3 Tracheal relaxation induced by KMUP-1 was attenuated by epithelium removal and by pretreatment with inhibitors of soluble guanylate cyclase (sGC) (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), 1 mM), nitric oxide synthase (N o -nitro-L-arginine methyl ester, 100 mM), K þ channels (tetraethylammonium, 10 mM), K ATP channels (glibenclamide, 1 mM), voltage-dependent K þ channels (4-aminopyridine, 100 mM) and Ca 2 þ -dependent K þ channels (charybdotoxin, 0.1 mM or apamin, 1 mM). 4 Both KMUP-1 (10 mM) and theophylline nonselectively and slightly inhibited the enzyme activity of PDE3, 4 and 5, suggesting that they are able to inhibit the metabolism of adenosine 3 0 ,5 0 -cyclic monophosphate (cyclic AMP) and guanosine 3 0 ,5 0 -cyclic monophosphate (cyclic GMP). Likewise, the effects of IBMX were also measured and its IC 50 values for PDE3, 4 and 5 were 6.571.2, 26.373.9 and 31.775.3 mM, respectively. 5 KMUP-1 (0.01-10 mM) augmented intracellular cyclic AMP and cyclic GMP levels in guinea-pig cultured tracheal smooth muscle cells. These increases in cyclic AMP and cyclic GMP were abolished in the presence of an adenylate cyclase inhibitor SQ 22536 (100 mM) and an sGC inhibitor ODQ (10 mM), respectively. 6 KMUP-1 (10 mM) increased the expression of protein kinase A (PKA RI ) and protein kinase G (PKG 1a1b ) in a time-dependent manner, but this was only significant for PKG after 9 h. 7 Intratracheal administration of tumour necrosis factor-a (TNF-a, 0.01 mg kg À1 ) induced bronchoconstriction and exhibited a time-dependent increase in lung resistance (R L ) and decrease in dynamic lung compliance (C dyn ). KMUP-1 (1.0 mg kg À1 ), injected intravenously for 10 min before the intratracheal TNF-a, reversed these changes in R L and C dyn . 8 These data indicate that KMUP-1 activates sGC, produces relaxation that was partly dependent on an intact epithelium, inhibits PDEs and increases intracellular cyclic AMP and cyclic GMP, which then increases PKA and PKG, leading to the opening of K þ channels and resulting tracheal relaxation.

SUMMARYHenoch±Scho Ènlein purpura (HSP) is a small vessel vasculitis characterized by increased serum IgA and IgA-dominant immune complex deposition in lesions. The involvement of IgA implies a probable role for TGF-b , a major factor in IgA production, in the pathogenesis of HSP. Among IgA antibodies, serum IgA anti-cardiolipin antibodies (aCL) have been found in many diseases, including vasculitis. In addition to the clinical presentations and laboratory parameters, we further investigated the roles of IgA aCL and TGF-b in childhood HSP. Twenty-six Chinese children with the diagnosis of HSP were enrolled. Blood samples from these patients were collected at both acute and convalescent stages. Intracellular staining of lymphocytes was performed to enumerate type 1 (interferon-gamma-secreting), type 2 (IL-4-secreting), and type 3 (TGF-b -secreting) helper T cells. Serum levels of TGF-b were detected by ELISA. Serum IgA aCL of 21 of 26 patients at the acute stage, 11 of them at the convalescent stage, were measured by ELISA. The data showed that IgA aCL serum levels were significantly elevated in patients compared with healthy controls (P , 0´001), and those patients at the convalescent stage (P , 0´001). In addition, TGF-b -secreting T cells were significantly elevated during the acute stage, and decreased at the convalescent stage. Although more studies are needed, the high prevalence of IgA aCL and increased TGF-b -secreting T cells in children with acute HSP revealed some points which should permit a better understanding of the pathogenesis of HSP.

SummaryRecently, sera from children with active Henoch-Schönlein purpura (HSP) have been found to enhance interleukin (IL)-8 production by human umbilical venous endothelial cells (HUVEC). To further determine the possible factor with the ability to enhance endothelial IL-8 production in sera from acute stage of HSP, 10 children with HSP at the acute stage and 10 healthy controls were enrolled. IgA antiendothelial cell antibodies (AECA) were detected by cell-based ELISA. Active sera with or without pretreatment with anti-human IgA antibody, sera of controls, and immunoglobulin A (IgA) derived from sera were used to stimulate the HUVEC. The ability of these factors to enhance endothelial IL-8 production was evaluated. Furthermore, signalling pathways were also assayed by different inhibitors, and confirmed by immunoblotting. Serum levels of IgA AECA in HPS patients at the acute stage were significantly higher than in controls ( P < < < < 0·001). The active sera could enhance endothelial IL-8 production ( P = = = = 0·004, compared with control sera), and the ability of these sera was mostly abolished when pretreated with fixed anti-human IgA antibody. The supernatant IL-8 levels of endothelial cells stimulated by IgA derived from acute stage of HSP were statistically higher than controls ( P < < < < 0·001). PD98059, an inhibitor of ERK phosphorylation, significantly reduced IgA AECA-stimulated endothelial IL-8. IgA AECA also enhanced the phosphorylation of ERK1 with a time-dependent manner. Together with these findings, it is concluded that IgA AECA derived from acute stage of HSP may bind to endothelial and enhance endothelial cells to produce IL-8 via MEK/ REK signalling pathway.

1 In isolated endothelium-intact or denuded rabbit corpus cavernosum preconstricted with phenylephrine, KMUP-1 (0.001 ± 10 mM) caused a concentration-dependent relaxation. 2 This relaxation of KMUP-1 was attenuated by endothelium removed, high K + and pretreatments with a soluble guanylyl cyclase (sGC) inhibitor ODQ (1 mM), a NOS inhibitor L-NAME (100 mM), a K + channel blocker TEA (10 mM), a K ATP channel blocker glibenclamide (1 mM), a voltage-dependent K + channel blocker 4-AP (100 mM) and Ca 2+-dependent K + channel blockers apamin (1 mM) and charybdotoxin (ChTX, 0.1 mM). 3 The relaxant responses of KMUP-1 (0.01, 0.05, 0.1 mM) together with a PDE inhibitor IBMX (0.5 mM) had additive actions on rabbit corpus cavernosum smooth muscle (CCSM). 4 KMUP-1 (0.01 ± 10 mM) induced increase of intracellular cyclic GMP level in the primary cell culture of rabbit CCSM. This increase in cyclic GMP content was abolished in the presence of ODQ (10 mM). 5 Both KMUP-1 and sildena®l at 0.2, 0.4, 0.6 mg kg 71 caused increases of intracavernous pressure (ICP) and duration of tumescene (DT) in a dose-dependent manner. These in vivo activities of ICP for sildena®l and KMUP-1 are consistent with those of in vitro eects of cyclic GMP. 6 KMUP-1 has the following merits: (1) inhibition of PDE or cyclic GMP breakdown, (2) stimulation of NO/sGC/cyclic GMP pathway, and (3) subsequent stimulation of K + channels, in rabbit CCSM. We suggest that these merits play prominent roles in KMUP-1-induced CCSM relaxation-associated increases of ICP and penile erection.

Background The clinical characteristics of central‐compartment‐type chronic rhinosinusitis (CRS) in East Asian individuals are not clear. We sought to investigate the clinical features and the cytokine profiles of central‐compartment‐type CRS in our patient group. Methods Adult patients diagnosed with bilateral CRS were recruited, and patients who had previously undergone sinus surgery and pansinusitis (Lund‐Mackay scores >23) were excluded. Central‐compartment‐type CRS was defined by both endoscopic and radiological features. The symptoms, inhalant allergen sensitization status, endoscopic findings, and radiological assessments were recorded and compared between patients with central‐compartment‐type CRS and other types of CRS. We also examined the extent of tissue eosinophilia and specific cytokine protein levels (eosinophil cationic protein [ECP], myeloperoxidase [MPO], immunoglobulin E [IgE], interleukin [IL]‐4, IL‐5, and IL‐13) in the sinonasal tissues. Results Central‐compartment‐type CRS was found in 16 (23.9%) patients, and non–central‐compartment‐type CRS was found in 51 (76.1%) patients. Hyposmia or anosmia as the major symptom was more common in the central‐compartment‐type CRS group. The numbers of eosinophils in tissue and serum were significantly higher in the central‐compartment‐type CRS patients. The presence of allergen sensitization was not significantly different between groups. The levels of IL‐5 and IL‐13 were increased in middle turbinate tissues of patients with central‐compartment‐type CRS. Conclusion Central‐compartment‐type CRS was associated with hyposmia or anosmia, eosinophilic subtypes, and elevated levels of IL‐5 and IL‐13 in middle turbinate tissues but not necessarily correlated with allergic disease in our patients.