Inhaled nitric oxide improves systemic oxygenation in infants with persistent pulmonary hypertension and may reduce the need for more invasive treatments.

Objective. To assess the clinical effects of rituximab therapy in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).Methods. The study group comprised 11 patients who had active AAV despite receiving maximally tolerated doses of cyclophosphamide or had contraindications for cyclophosphamide use. All patients had ANCA reactive against proteinase 3. The patients received rituximab infusions and glucocorticoids to induce remission. Three patients also received plasma exchange. No other immunosuppressive agents were used. Glucocorticoids were tapered as soon as control of disease activity was achieved. Disease activity was monitored using the Birmingham Vasculitis Activity Score, modified for Wegener's granulomatosis.Results. Rituximab therapy was well tolerated by all patients, and adverse events were rare. Following the rituximab infusions, circulating B lymphocytes became undetectable, and ANCA titers decreased significantly. Remission was achieved in all patients and was maintained while B lymphocytes were absent.Conclusion. The ability to achieve stable remissions with rituximab in patients with AAV refractory to conventional therapy suggests that B lymphocyte depletion may be a safe, effective, mechanism-based treatment modality for treatment of patients with these conditions.

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We tested the hypothesis that prolonged serum deprivation would allow a subset of cultured airway myocytes to reacquire the abundant contractile protein content, marked shortening capacity, and elongated morphology characteristic of contractile cells within intact tissue. Passage 1 or 2 canine tracheal smooth muscle (SM) cells were grown to confluence, then serum deprived for up to 19 days. During serum deprivation, two differentiation pathways emerged. One-sixth of the cells developed an elongated morphology and aligned into bundles. Elongated myocytes contained cables of contractile myofilaments, dense bodies, gap junctions, and membrane caveoli, ultrastructural features of contractile SM in tissue. These cells immunostained intensely for SM α-actin, SM myosin heavy chain (MHC), and SM22 (an SM-specific actin-binding protein), and Western analysis of culture lysates disclosed 1.8 (SM α-actin)-, 7.7 (SM MHC)-, and 5.8 (SM22)-fold protein increases during serum deprivation. Immunoreactive M3 muscarinic receptors were present in dense foci distributed throughout elongated, SM MHC-positive myocytes. ACh (10−3 M) induced a marked shortening (59.7 ± 14.4% of original length) in 62% of elongated myocytes made semiadherent by gentle proteolytic digestion, and membrane bleb formation (a consequence of contraction) occurred in all stimulated cells that remained adherent and so did not shorten. Cultured airway myocytes that did not elongate during serum deprivation instead became short and flattened, lost immunoreactivity for contractile proteins, lacked the M3 muscarinic-receptor expression pattern seen in elongated cells, and exhibited no contractile response to ACh. Thus we demonstrate that prolonged serum deprivation induces distinct differentiation pathways in confluent cultured tracheal myocytes and that one subpopulation acquires an unequivocally functional contractile phenotype in which structure and function resemble contractile myocytes from intact tissue.

Previous studies have suggested that the proinflammatory cytokine, TNF-␣, contributes to airway hyperresponsivness by altering airway smooth muscle (ASM) Ca 2ϩ responses to agonist stimulation. The present study examined the effects of TNF-␣ on Ca 2ϩ influx pathways in cultured human ASM cells (HASMCs). Proteins encoded by the transient receptor potential (TRP) gene family function as channels through which receptor-operated and store-operated Ca 2ϩ entry (SOCE) occur. In the present study, the presence of TRPC1, TRPC3, TRPC4, TRPC5, and TRPC6 mRNA and protein expression was confirmed in cultured HASMCs using RT-PCR and Western blot analysis. TNF-␣ treatment significantly increased TRPC3 mRNA and protein levels in HASMCs as well as SOCE. TNF-␣ treatment also increased both the peak and plateau intracellular Ca 2ϩ concentration responses in HASMCs elicited by acetylcholine and bradykinin. The effects of TNF-␣ treatment on SOCE and agonist-induced intracellular Ca 2ϩ concentration responses were attenuated using small interfering RNA transfection, which knocked down TRPC3 expression. Thus, in inflammatory airway diseases, TNF-␣ treatment may result in increased myocyte activation due to altered Ca 2ϩ influx pathways. These results suggest that TRPC3 may be an important therapeutic target in inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease.