Management of Acute Episodes of Clarkson Disease (Monoclonal Gammopathy-Associated Systemic Capillary Leak Syndrome) With Intravenous Immunoglobulins.

Monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome (ISCLS, Clarkson disease) is a rare disorder defined by transient but recurrent bouts of hypotensive shock and anasarca resulting from plasma extravasation. Although prophylactic treatment with high-dose intravenous immunoglobulins (IVIG, 1-2 g/kg/mo) prevents most disease flares, its utility for acute episodes of ISCLS is unclear. Here, we report the results of a retrospective study of subjects with acute ISCLS treated at or near the onset of symptoms with IVIG. We found that administration of IVIG with minimal additional intravenous fluids was safe and associated with rapid clinical improvement. IVIG given close to the onset of ISCLS-related symptoms is associated with a favorable outcome.

The Arabidopsis cellulose synthase complex: a proposed hexamer of CESA trimers in an equimolar stoichiometry.

Cellulose is the most abundant renewable polymer on Earth and a major component of the plant cell wall. In vascular plants, cellulose synthesis is catalyzed by a large, plasma membrane-localized cellulose synthase complex (CSC), visualized as a hexameric rosette structure. Three unique cellulose synthase (CESA) isoforms are required for CSC assembly and function. However, elucidation of either the number or stoichiometry of CESAs within the CSC has remained elusive. In this study, we show a 1:1:1 stoichiometry between the three Arabidopsis thaliana secondary cell wall isozymes: CESA4, CESA7, and CESA8. This ratio was determined utilizing a simple but elegant method of quantitative immunoblotting using isoform-specific antibodies and (35)S-labeled protein standards for each CESA. Additionally, the observed equimolar stoichiometry was found to be fixed along the axis of the stem, which represents a developmental gradient. Our results complement recent spectroscopic analyses pointing toward an 18-chain cellulose microfibril. Taken together, we propose that the CSC is composed of a hexamer of catalytically active CESA trimers, with each CESA in equimolar amounts. This finding is a crucial advance in understanding how CESAs integrate to form higher order complexes, which is a key determinate of cellulose microfibril and cell wall properties.