Citations

Abstract Membrane curvature is closely associated with spatial distribution of lipids and curvature can influence the formation of lipid rafts in biological membranes. However, it is still unclear how the curvature elasticity plays a role on the asymmetric distribution of lipids across the membrane leaflets, especially, during the process of the raft domain growth. Using supported lipid membranes on wedge‐shaped substrates with alternating positive and negative curvatures, curvature‐mediated asymmetry of lipid raft domains is observed across the membrane leaflets accompanied by glycolipid receptor (GM 1 and GT 1 b) localization. The raft domains initially appear only in a membrane leaflet possessing negative curvatures. In the presence of the interleaflet coupling, they evolve to generate the transverse registry across the membrane bilayer. It is shown that a human recombinant antibody rHIgM12 is co‐localized with the rafts formed at the peaks and valleys of the wedge substrate, indicating that the spatial distribution of its receptor (GT 1 b) is indeed manifested by the site‐specific formation of asymmetric raft domains through the curvature elasticity. The platform can be used to explore the mechanism for the leaflet asymmetry and lipid sorting in terms of the membrane curvature, the composition, and the receptor presentation.

BackgroundSpontaneous pneumomediastinum (SP) is an uncommon disorder but has been described in cases with connective tissue diseases (CTDs), most commonly dermatomyositis and polymyositis. We aimed to explore this relationship by analyzing the characteristics of CTD patients with SP.MethodsUsing a computer-assisted search, we identified 25 patients with CTD and SP evaluated between January 1997 and December 2016 at our institution. Clinicoradiologic characteristics, treatment, and outcomes were extracted and chest computed tomography studies analyzed.ResultsWe identified 25 patients with CTD and SP. Median (range) age at SP occurrence was 55 (18–82) years, and 60% of the patients were women. Smoking history was present in 37%. Spontaneous pneumomediastinum was symptomatic in 56% of patients. Eighteen patients (72%) had a known CTD diagnosis, and 20 patients (80%) manifested radiologic evidence of interstitial lung disease. Spontaneous pneumomediastinum diagnosis was achieved with chest radiography in 20% of cases and chest computed tomography in the other cases. Spontaneous pneumomediastinum was managed with expectant observation alone in 22 cases (88%). Four patients (16%) had concomitant pneumothorax, 1 of whom required chest tube drainage. There were no deaths attributable to SP during the median (range) follow-up of 13 (0–174) months. Cumulative survival was 52% at 1 year and 40% at 2 years.ConclusionsSpontaneous pneumomediastinum is an uncommon manifestation of CTD and usually occurs in the presence of interstitial lung disease. Although SP seems to be associated with a relatively benign short-term course, occurrence of SP in CTD patients may be a poor prognostic factor.