The G protein-coupled receptor (GPCR) rhodopsin self-assembles into supramolecular structures in native bilayers, but the structural determinants of receptor oligomerization are not known. We carried ...out multiple self-assembly coarse-grained molecular dynamics (CGMD) simulations of model membranes containing up to 64 molecules of the visual receptor rhodopsin over time scales reaching 100 μs. The simulations show strong preferential interaction modes between receptors. Two primary modes of receptor–receptor interactions are consistent with umbrella sampling/potential of mean force (PMF) calculations as a function of the distance between a pair of receptors. The preferential interfaces, involving helices (H) 1/8, 4/5 and 5, present no energy barrier to forming a very stable receptor dimer. Most notably, the PMFs show that the preferred rhodopsin dimer exists in a tail-to-tail conformation, with the interface comprising transmembrane H1/H2 and amphipathic H8 at the extracellular and cytoplasmic surfaces, respectively. This dimer orientation is in line with earlier electron microscopy, X-ray, and cross-linking experiments of rhodopsin and other GPCRs. Less stable interfaces, involving H4 and H6, have a free energy barrier for desolvation (delipidation) of the interfaces and appear to be designed to stabilize “lubricated” (i.e., lipid-coated) dimers. The overall CGMD strategy used here is general and can be applied to study the homo- and heterodimerization of GPCRs and other transmembrane proteins. Systematic extension of the work will deepen our understanding of the forces involved in the membrane organization of integral membrane proteins.
Summary Background Ductal carcinoma in situ is currently managed with excision, radiotherapy, and adjuvant hormone therapy, usually tamoxifen. We postulated that an aromatase inhibitor would be safer ...and more effective. We therefore undertook this trial to compare anastrozole versus tamoxifen in postmenopausal women with ductal carcinoma in situ undergoing lumpectomy plus radiotherapy. Methods The double-blind, randomised, phase 3 National Surgical Adjuvant Breast and Bowel Project (NSABP) B-35 trial was done in 333 participating NSABP centres in the USA and Canada. Postmenopausal women with hormone-positive ductal carcinoma in situ treated by lumpectomy with clear resection margins and whole-breast irradiation were enrolled and randomly assigned (1:1) to receive either oral tamoxifen 20 mg per day (with matching placebo in place of anastrozole) or oral anastrozole 1 mg per day (with matching placebo in place of tamoxifen) for 5 years. Randomisation was stratified by age (<60 vs ≥60 years) and patients and investigators were masked to treatment allocation. The primary outcome was breast cancer-free interval, defined as time from randomisation to any breast cancer event (local, regional, or distant recurrence, or contralateral breast cancer, invasive disease, or ductal carcinoma in situ), analysed by intention to treat. This study is registered with ClinicalTrials.gov , number NCT00053898 , and is complete. Findings Between Jan 1, 2003, and June 15, 2006, 3104 eligible patients were enrolled and randomly assigned to the two treatment groups (1552 to tamoxifen and 1552 to anastrozole). As of Feb 28, 2015, follow-up information was available for 3083 patients for overall survival and 3077 for all other disease-free endpoints, with median follow-up of 9·0 years (IQR 8·2–10·0). In total, 212 breast cancer-free interval events occurred: 122 in the tamoxifen group and 90 in the anastrozole group (HR 0·73 95% CI 0·56–0·96, p=0·0234). A significant time-by-treatment interaction (p=0·0410) became evident later in the study. There was also a significant interaction between treatment and age group (p=0·0379), showing that anastrozole is superior only in women younger than 60 years of age. Adverse events did not differ between the groups, except for thrombosis or embolism—a known side-effect of tamoxifen—for which there were 17 grade 4 or worse events in the tamoxifen group versus four in the anastrozole group. Interpretation Compared with tamoxifen, anastrozole treatment provided a significant improvement in breast cancer-free interval, mainly in women younger than 60 years of age. This finding means that women will benefit from having a choice of effective agents for ductal carcinoma in situ. Funding US National Cancer Institute and AstraZeneca Pharmaceuticals LP.
To evaluate the safety, efficacy, and performance of the TriGuard™ HDH Embolic Deflection Device (TriGuard) compared with no cerebral protection in patients undergoing transcatheter aortic valve ...implantation (TAVI).
From February 2014 to March 2015, 85 subjects undergoing TAVI at 13 centres in Europe and Israel were randomized to TriGuard protection vs. no protection. Subjects underwent neurologic and cognitive evaluation at baseline, pre-discharge and 30 days; cerebral diffusion-weighted magnetic resonance imaging was performed at 4 ± 2 days post-procedure and at 30 days. Technical success, which included complete 3-vessel cerebral coverage, was achieved in 88.9% (40/45) of cases. The primary in-hospital procedural safety endpoint (death, stroke, life-threatening or disabling bleeding, stage 2 or 3 acute kidney injury, or major vascular complications) occurred in 21.7% of TriGuard and 30.8% of control subjects (P = 0.34). In the Per Treatment population (subjects with complete three-vessel cerebral coverage), TriGuard use was associated with greater freedom from new ischaemic brain lesions (26.9 vs. 11.5%), fewer new neurologic deficits detected by the National Institutes of Health Stroke Scale (3.1 vs. 15.4%), improved Montreal Cognitive Assessment (MoCA) scores, better performance on a delayed memory task (P = 0.028) at discharge, and a >2-fold increase in recovery of normal cognitive function (MoCA score >26) at 30 days.
TriGuard cerebral protection during TAVI is safe and complete cerebral vessel coverage was achieved in 89% of subjects. In this exploratory study, subjects undergoing protected TAVI had more freedom from ischaemic brain lesions, fewer neurologic deficits, and improved cognitive function in some domains at discharge and 30 days compared with controls.
The public health implications of e-cigarettes depend, in part, on whether e-cigarette use affects the risk of cigarette smoking.
To perform a systematic review and meta-analysis of longitudinal ...studies that assessed initial use of e-cigarettes and subsequent cigarette smoking.
PubMed, EMBASE, Cochrane Library, Web of Science, the 2016 Society for Research on Nicotine and Tobacco 22nd Annual Meeting abstracts, the 2016 Society of Behavioral Medicine 37th Annual Meeting & Scientific Sessions abstracts, and the 2016 National Institutes of Health Tobacco Regulatory Science Program Conference were searched between February 7 and February 17, 2017. The search included indexed terms and text words to capture concepts associated with e-cigarettes and traditional cigarettes in articles published from database inception to the date of the search.
Longitudinal studies reporting odds ratios for cigarette smoking initiation associated with ever use of e-cigarettes or past 30-day cigarette smoking associated with past 30-day e-cigarette use. Searches yielded 6959 unique studies, of which 9 met inclusion criteria (comprising 17 389 adolescents and young adults).
Study quality and risk of bias were assessed using the Newcastle-Ottawa Scale and the Risk of Bias in Non-randomized Studies of Interventions tool, respectively. Data and estimates were pooled using random-effects meta-analysis.
Among baseline never cigarette smokers, cigarette smoking initiation between baseline and follow-up. Among baseline non-past 30-day cigarette smokers who were past 30-day e-cigarette users, past 30-day cigarette smoking at follow-up.
Among 17 389 adolescents and young adults, the ages ranged between 14 and 30 years at baseline, and 56.0% were female. The pooled probabilities of cigarette smoking initiation were 30.4% for baseline ever e-cigarette users and 7.9% for baseline never e-cigarette users. The pooled probabilities of past 30-day cigarette smoking at follow-up were 21.5% for baseline past 30-day e-cigarette users and 4.6% for baseline non-past 30-day e-cigarette users. Adjusting for known demographic, psychosocial, and behavioral risk factors for cigarette smoking, the pooled odds ratio for subsequent cigarette smoking initiation was 3.62 (95% CI, 2.42-5.41) for ever vs never e-cigarette users, and the pooled odds ratio for past 30-day cigarette smoking at follow-up was 4.28 (95% CI, 2.52-7.27) for past 30-day e-cigarette vs non-past 30-day e-cigarette users at baseline. A moderate level of heterogeneity was observed among studies (I2 = 60.1%).
e-Cigarette use was associated with greater risk for subsequent cigarette smoking initiation and past 30-day cigarette smoking. Strong e-cigarette regulation could potentially curb use among youth and possibly limit the future population-level burden of cigarette smoking.
Synaptic transmission is bioenergetically demanding, and the diverse processes underlying synaptic plasticity elevate these demands. Therefore, mitochondrial functions, including ATP synthesis and ...Ca2+ handling, are likely essential for plasticity. Although axonal mitochondria have been extensively analyzed, LTP is predominantly induced postsynaptically, where mitochondria are understudied. Additionally, though mitochondrial fission is essential for their function, signaling pathways that regulate fission in neurons remain poorly understood. We found that NMDAR-dependent LTP induction prompted a rapid burst of dendritic mitochondrial fission and elevations of mitochondrial matrix Ca2+. The fission burst was triggered by cytosolic Ca2+ elevation and required CaMKII, actin, and Drp1, as well as dynamin 2. Preventing fission impaired mitochondrial matrix Ca2+ elevations, structural LTP in cultured neurons, and electrophysiological LTP in hippocampal slices. These data illustrate a novel pathway whereby synaptic activity controls mitochondrial fission and show that dynamic control of fission regulates plasticity induction, perhaps by modulating mitochondrial Ca2+ handling.
•Chemical LTP induction induces a rapid burst of dendritic mitochondrial fission•This burst is regulated by cytosolic Ca2+, CaMKII, actin, and Drp1, as well as by Dyn2•Chem LTP induction increases dendritic mitochondrial Ca2+, which requires fission•Dendritic fission is required for structural and electrophysiological LTP
Divakaruni et al. showed that LTP induction prompts dendritic mitochondrial fission and mitochondrial Ca2+ transients (mCaTs), delineated a novel mechanism of activity-dependent fission regulation in neurons, and demonstrated that mCaTs and both structural and electrophysiological LTP require mitochondrial fission.
Copper is controlled by a sophisticated network of transport and storage proteins within mammalian cells, yet its uptake and efflux occur with rapid kinetics. Present as Cu(I) within the reducing ...intracellular environment, the nature of this labile copper pool remains elusive. While glutathione is involved in copper homeostasis and has been assumed to buffer intracellular copper, we demonstrate with a ratiometric fluorescent indicator, crisp-17, that cytosolic Cu(I) levels are buffered to the vicinity of 1 aM, where negligible complexation by glutathione is expected. Enabled by our phosphine sulfide-stabilized phosphine (PSP) ligand design strategy, crisp-17 offers a Cu(I) dissociation constant of 8 aM, thus exceeding the binding affinities of previous synthetic Cu(I) probes by four to six orders of magnitude. Two-photon excitation microscopy with crisp-17 revealed rapid, reversible increases in intracellular Cu(I) availability upon addition of the ionophoric complex CuGTSM or the thiol-selective oxidant 2,2′-dithiodipyridine (DTDP). While the latter effect was dramatically enhanced in 3T3 cells grown in the presence of supplemental copper and in cultured Menkes mutant fibroblasts exhibiting impaired copper efflux, basal Cu(I) availability in these cells showed little difference from controls, despite large increases in total copper content. Intracellular copper is thus tightly buffered by endogenous thiol ligands with significantly higher affinity than glutathione. The dual utility of crisp-17 to detect normal intracellular buffered Cu(I) levels as well as to probe the depth of the labile copper pool in conjunction with DTDP provides a promising strategy to characterize perturbations of cellular copper homeostasis.
Summary Background The NSABP B-35 trial compared 5 years of treatment with anastrozole versus tamoxifen for reducing subsequent occurrence of breast cancer in postmenopausal patients with ductal ...carcinoma in situ. This report assesses the effect of these drugs on quality of life and symptoms. Methods The study was done at 333 hospitals in North America. Postmenopausal women with hormone-positive ductal carcinoma in situ treated by lumpectomy with clear resection margins and whole breast irradiation were randomly assigned to receive either tamoxifen (20 mg/day) or anastrazole (1 mg/day) for 5 years, stratified by age (<60 years vs ≥60 years). Patients and investigators were masked to treatment allocation. Patients completed questionnaires at baseline and every 6 months thereafter for 6 years. The primary outcomes were SF-12 physical and mental health component scale scores, and vasomotor symptoms (as per the BCPT symptom scale). Secondary outcomes were vaginal symptoms and sexual functioning. Exploratory outcomes were musculoskeletal pain, bladder symptoms, gynaecological symptoms, cognitive symptoms, weight problems, vitality, and depression. We did the analyses by intention to treat, including patients who completed questionnaires at baseline and at least once during follow-up. This study is registered with ClinicalTrials.gov , NCT00053898. Findings Between Jan 6, 2003, and June 15, 2006, 3104 patients were enrolled in the study, of whom 1193 were included in the quality-of-life substudy: 601 assigned to tamoxifen and 592 assigned to anastrozole. We detected no significant difference between treatment groups for: physical health scores (mean severity score 46·72 for tamoxifen vs 45·85 for anastrozole; p=0·20), mental health scores (52·38 vs 51·48; p=0·38), energy and fatigue (58·34 vs 57·54; p=0·86), or symptoms of depression (6·19 vs 6·39; p=0·46) over 5 years. Vasomotor symptoms (1·33 vs 1·17; p=0·011), difficulty with bladder control (0·96 vs 0·80; p=0·0002), and gynaecological symptoms (0·29 vs 0·18; p<0·0001) were significantly more severe in the tamoxifen group than in the anastrozole group. Musculoskeletal pain (1·50 vs 1·72; p=0·0006) and vaginal symptoms (0·76 vs 0·86; p=0·035) were significantly worse in the anastrozole group than in the tamoxifen group. Sexual functioning did not differ significantly between the two treatments (43·65 vs 45·29; p=0·56). Younger age was significantly associated with more severe vasomotor symptoms (mean severity score 1·45 for age <60 years vs 0·65 for age ≥60 years; p=0·0006), vaginal symptoms (0·98 vs 0·65; p<0·0001), weight problems (1·32 vs 1·02; p<0·0001), and gynaecological symptoms (0·26 vs 0·22; p=0·014). Interpretation Given the similar efficacy of tamoxifen and anastrozole for women older than age 60 years, decisions about treatment should be informed by the risk for serious adverse health effects and the symptoms associated with each drug. For women younger than 60 years old, treatment decisions might be driven by efficacy (favouring anastrozole); however, if the side-effects of anastrozole are intolerable, then switching to tamoxifen is a good alternative. Funding US National Cancer Institute, AstraZeneca Pharmaceuticals.
The use of adjuvant chemotherapy in patients with breast cancer may be guided by clinicopathological factors and a score based on a 21-gene assay to determine the risk of recurrence. Whether the ...level of clinical risk of breast cancer recurrence adds prognostic information to the recurrence score is not known.
We performed a prospective trial involving 9427 women with hormone-receptor-positive, human epidermal growth factor receptor 2-negative, axillary node-negative breast cancer, in whom an assay of 21 genes had been performed, and we classified the clinical risk of recurrence of breast cancer as low or high on the basis of the tumor size and histologic grade. The effect of clinical risk was evaluated by calculating hazard ratios for distant recurrence with the use of Cox proportional-hazards models. The initial endocrine therapy was tamoxifen alone in the majority of the premenopausal women who were 50 years of age or younger.
The level of clinical risk was prognostic of distant recurrence in women with an intermediate 21-gene recurrence score of 11 to 25 (on a scale of 0 to 100, with higher scores indicating a worse prognosis or a greater potential benefit from chemotherapy) who were randomly assigned to endocrine therapy (hazard ratio for the comparison of high vs. low clinical risk, 2.73; 95% confidence interval CI, 1.93 to 3.87) or to chemotherapy plus endocrine (chemoendocrine) therapy (hazard ratio, 2.41; 95% CI, 1.66 to 3.48) and in women with a high recurrence score (a score of 26 to 100), all of whom were assigned to chemoendocrine therapy (hazard ratio, 3.17; 95% CI, 1.94 to 5.19). Among women who were 50 years of age or younger who had received endocrine therapy alone, the estimated (±SE) rate of distant recurrence at 9 years was less than 5% (≤1.8±0.9%) with a low recurrence score (a score of 0 to 10), irrespective of clinical risk, and 4.7±1.0% with an intermediate recurrence score and low clinical risk. In this age group, the estimated distant recurrence at 9 years exceeded 10% among women with a high clinical risk and an intermediate recurrence score who received endocrine therapy alone (12.3±2.4%) and among those with a high recurrence score who received chemoendocrine therapy (15.2±3.3%).
Clinical-risk stratification provided prognostic information that, when added to the 21-gene recurrence score, could be used to identify premenopausal women who could benefit from more effective therapy. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT00310180.).
Major depressive disorder emerges from the complex interactions of biological systems that span genes and molecules through cells, networks, and behavior. Establishing how neurobiological processes ...coalesce to contribute to depression requires a multiscale approach, encompassing measures of brain structure and function as well as genetic and cell-specific transcriptional data. Here, we examine anatomical (cortical thickness) and functional (functional variability, global brain connectivity) correlates of depression and negative affect across three population-imaging datasets: UK Biobank, Brain Genomics Superstruct Project, and Enhancing Neuro- Imaging through Meta Analysis (ENIGMA; combined n ≥ 23,723). Integrative analyses incorporate measures of cortical gene expression, postmortem patient transcriptional data, depression genome-wide association study (GWAS), and single-cell gene transcription. Neuroimaging correlates of depression and negative affect were consistent across three independent datasets. Linking ex vivo gene down-regulation with in vivo neuroimaging, we find that transcriptional correlates of depression imaging phenotypes track gene down-regulation in postmortem cortical samples of patients with depression. Integrated analysis of single-cell and Allen Human Brain Atlas expression data reveal somatostatin interneurons and astrocytes to be consistent cell associates of depression, through both in vivo imaging and ex vivo cortical gene dysregulation. Providing converging evidence for these observations, GWAS-derived polygenic risk for depression was enriched for genes expressed in interneurons, but not glia. Underscoring the translational potential of multiscale approaches, the transcriptional correlates of depression-linked brain function and structure were enriched for disorder-relevant molecular pathways. These findings bridge levels to connect specific genes, cell classes, and biological pathways to in vivo imaging correlates of depression.
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