No abstract

Ryanodine receptors (RyRs) are a class of giant ion channels with molecular mass over 2.2 mega-Daltons. These channels mediate calcium signaling in a variety of cells. Since more than 80% of the RyR protein is folded into the cytoplasmic assembly and the remaining residues form the transmembrane domain, it has been hypothesized that the activation and regulation of RyR channels occur through an as yet uncharacterized long-range allosteric mechanism. Here we report the characterization of a Ca2+-activated open-state RyR1 structure by cryo-electron microscopy. The structure has an overall resolution of 4.9 Å and a resolution of 4.2 Å for the core region. In comparison with the previously determined apo/closed-state structure, we observed long-range allosteric gating of the channel upon Ca2+ activation. In-depth structural analyses elucidated a novel channel-gating mechanism and a novel ion selectivity mechanism of RyR1. Our work not only provides structural insights into the molecular mechanisms of channel gating and regulation of RyRs, but also sheds light on structural basis for channel-gating and ion selectivity mechanisms for the six-transmembrane-helix cation channel family.

Primary small cell oesophageal carcinoma (SCOC) is rare, prognosis is poor and there is no established optimum treatment strategy. It shares many clinicopathologic features with small cell carcinoma of the lung; therefore, a similar staging and treatment strategy was adopted. Sixteen cases referred to Velindre hospital between 1998 and 2005 were identified. Patients received platinum-based combination chemotherapy if appropriate. Those with limited disease (LD) received radical radiotherapy (RT) to all sites of disease on completion of chemotherapy. Median survival of all patients was 13.2 months. Median survival of patients with LD was significantly longer than those with extensive disease (24.4 vs 9.1 months, P ¼ 0.034). This is one of the largest single institution series in the world literature. Combined modality therapy using platinum-based combination chemotherapy and radical RT may allow a nonsurgical approach to management, avoiding the morbidity of oesophagectomy. Prophylactic cranial irradiation is controversial, and should be discussed on an individual basis.

Background:The SCOPE-1 study tested the role of adding cetuximab to conventional definitive chemoradiotherapy (dCRT), and demonstrated greater toxicity and worse survival outcomes. We present the long-term outcomes and patterns of recurrence.Methods:SCOPE-1 was a phase II/III trial in which patients were randomised to cisplatin 60 mg m−2 (day 1) and capecitabine 625 mg m−2 bd (days 1–21) for four cycles +/− cetuximab 400 mg m−2 day 1 then by 250 mg m−2 weekly. Radiotherapy consisted of 50 Gy/25# given concurrently with cycles 3 and 4. Recruitment was between February 2008 and February 2012, when the IDMC recommended closure on the basis of futility.Results:About 258 patients (dCRT=129; dCRT+cetuximab (dCRT+C)=129) were recruited from 36 centres. About 72.9% (n=188) had squamous cell histology. The median follow-up (IQR) was 46.2 (35.9–48.3) months for surviving patients. The median overall survival (OS; months; 95% CI) was 34.5 (24.7–42.3) in dCRT and 24.7 (18.6–31.3) in dCRT+C (hazard ratio (HR)=1.25, 95% CIs: 0.93–1.69, P=0.137). Median progression-free survival (PFS; months; 95% CI) was 24.1 (15.3–29.9) and 15.9 (10.7–20.8) months, respectively (HR=1.28, 95% CIs: 0.94–1.75; P=0.114). On multivariable analysis only earlier stage, full-dose RT, and higher cisplatin dose intensity were associated with improved OS.Conclusions:The mature analysis demonstrates that the dCRT regimen used in the study provided useful survival outcomes despite its use in patients who were largely unfit for surgery or who had inoperable disease. Given the competing risk of systemic and local failure, future studies should continue to focus on enhancing local control as well as optimising systemic therapy.