Phospholipids Differentially Regulate Ca 2+ Binding to Synaptotagmin‑1

Synaptotagmin-1 (Syt-1) is a calcium sensing protein that is resident in synaptic vesicles. It is well established that Syt-1 is essential for fast and synchronous neurotransmitter release. However, the role of Ca2+ and phospholipid binding in the function of Syt-1, and ultimately in neurotransmitter release, is unclear. Here, we investigate the binding of Ca2+ to Syt-1, first in the absence of lipids, using native mass spectrometry to evaluate individual binding affinities. Syt-1 binds to one Ca2+ with a K D ∼ 45 μM. Each subsequent binding affinity (n ≥ 2) is successively unfavorable. Given that Syt-1 has been reported to bind anionic phospholipids to modulate the Ca2+ binding affinity, we explored the extent that Ca2+ binding was mediated by selected anionic phospholipid binding. We found that phosphatidylinositol 4,5-bisphosphate (PI­(4,5)­P2) and dioleoylphosphatidylserine (DOPS) positively modulated Ca2+ binding. However, the extent of Syt-1 binding to phosphatidylinositol 3,5-bisphosphate (PI­(3,5)­P2) was reduced with increasing [Ca2+]. Overall, we find that specific lipids differentially modulate Ca2+ binding. Given that these lipids are enriched in different subcellular compartments and therefore may interact with Syt-1 at different stages of the synaptic vesicle cycle, we propose a regulatory mechanism involving Syt-1, Ca2+, and anionic phospholipids that may also control some aspects of vesicular exocytosis

Mars Sample Return Using Commercial Capabilities: Mission Architecture Overview

Mars Sample Return (MSR) is the highest priority science mission for the next decade as recommended by the recent Decadal Survey of Planetary Science. This paper presents an overview of a feasibility study for an MSR mission. The objective of the study was to determine whether emerging commercial capabilities can be used to reduce the number of mission systems and launches required to return the samples, with the goal of reducing mission cost. We report the feasibility of a complete and closed MSR mission design using the following scenario that covers three synodic launch opportunities, beginning with the 2022 opportunity: A Falcon Heavy injects a SpaceX Red Dragon capsule and trunk onto a Trans Mars Injection (TMI) trajectory. The capsule is modified to carry all the hardware needed to return samples collected on Mars including a Mars Ascent Vehicle (MAV), an Earth Return Vehicle (ERV), and hardware to transfer a sample collected in a previously landed rover mission to the ERV. The Red Dragon descends to land on the surface of Mars using Super Sonic Retro Propulsion (SSRP). After previously collected samples are transferred to the ERV, the single-stage MAV launches the ERV from the surface of Mars. The MAV uses a storable liquid bi-propellant propulsion system to deliver the ERV to a Mars phasing orbit. After a brief phasing period, the ERV, which also uses a storable bi-propellant system, performs a Trans Earth Injection (TEI) burn. Upon arrival at Earth, the ERV performs Earth and lunar swing-bys and is placed into a lunar trailing circular orbit - an Earth orbit, at lunar distance. A later mission, using Dragon and launched by a Falcon Heavy, performs a rendezvous with the ERV in the lunar trailing orbit, retrieves the sample container and breaks the chain of contact with Mars by transferring the sample into a sterile and secure container. With the sample contained, the retrieving spacecraft makes a controlled Earth re-entry preventing any unintended release of pristine martian materials into the Earth's biosphere. The analysis methods employed standard and specialized aerospace engineering tools. Mission system elements were analyzed with either direct techniques or by using parametric mass estimating relationships (MERs). The architecture was iterated until overall mission convergence was achieved on at least one path. Subsystems analyzed in this study include support structures, power system, nose fairing, thermal insulation, actuation devices, MAV exhaust venting, and GN&C. Best practice application of loads, mass growth contingencies, and resource margins were used. For Falcon Heavy capabilities and Dragon subsystems we utilized publically available data from SpaceX, published analyses from other sources, as well as our own engineering and aerodynamic estimates. Earth Launch mass is under 11 mt, which is within the estimated capability of a Falcon Heavy, with margin. Total entry masses between 7 and 10 mt were considered with closure occurring between 9 and 10 mt. Propellant mass fractions for each major phase of the EDL - Entry, Terminal Descent, and Hazard Avoidance - have been derived. An assessment of the effect of the entry conditions on the thermal protection system (TPS), currently in use for Dragon missions, shows no significant stressors. A useful payload mass of 2.0 mt is provided and includes mass growth allowances for the MAV, the ERV, and mission unique equipment. We also report options for the MAV and ERV, including propulsion systems, crewed versus robotic retrieval mission, as well as direct Earth entry. International planetary protection policies as well as verifiable means of compliance will have a large impact on any MSR mission design. We identify areas within our architecture where such impacts occur. We also describe preliminary compliance measures that will be the subject of future work. This work shows that emerging commercial capabilities as well as new methodologies can be used to efficiently support an important planetary science objective. The work also has applications for human exploration missions that use propulsive EDL technique

A catalog of IRAS observations of large optical galaxies

A catalog is presented of the IRAS observations of 85 galaxies listed in the Second Reference Catalogue of Bright Galaxies with blue-light isophotal diameters greater than 8'. “Total” flux densities at 12, 25, 60, and 100 µm, obtained from spatial maps constructed from co-added IRAS detector data, are reported. Infrared brightness profiles of the detected galaxies and infrared surface brightness contour maps of the galaxies for which structural features were resolved are displayed in an atlas. A far-infrared classification scheme based on the degree of central concentration and spatial structure of the 60 µm emission of the best-resolved galaxies is proposed. The 60 µm and blue-light isophotal diameters of the largest galaxies are compared

Effects of erythropoietin therapy on the lipid profile in end-stage renal failure

Effects of erythropoietin therapy on the lipid profile in end-stage renal failure. To evaluate the effects of erythropoietin (EPO) therapy on the lipid profile in end-stage renal failure, we undertook a prospective study in patients on both hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). One hundred and twelve patients (81 HD, 31 CAPD) were enrolled into the study. Lipid parameters [that is, total cholesterol and the LDL and HDL subfractions, triglycerides, lipoprotein (a), apoproteins A and B], full blood count, iron studies, B12, folate, blood urea, aluminium and serum parathyroid hormone were measured prior to commencement of EPO therapy. Ninety-five patients were reassessed 5.2 ± 0.3 (mean ± SEM) months later and 53 patients underwent a further assessment 13.1 ± 0.6 months after the commencement of EPO, giving an overall follow-up of 10.0 ± 0.6 months in 95 patients. As expected, EPO treatment was associated with an increase in hemoglobin (7.7 ± 0.1 vs. 9.9 ± 0.2 g/dl; P < 0.001) and a decrease in ferritin (687 ± 99 vs. 399 ± 69 µg/liter; P < 0.01). A significant fall in total cholesterol occurred (5.8 ± 0.1 vs. 5.4 ± 0.2 mmol/liter; P < 0.05) in association with a fall in apoprotein B (1.15 ± 0.04 vs. 1.04 ± 0.06; P < 0.05) and serum triglycerides (2.26 ± 0.14 vs. 1.99 ± 0.21; P < 0.05) during the course of the study. Other lipid parameters did not change, although there was a trend towards improvement. These changes correlated with the increase in Hb (P < 0.001 in each case), and the reduction in ferritin for total cholesterol (P < 0.02), LDL cholesterol (P < 0.03), and to a lesser extent apoprotein B (P < 0.07). No difference was observed in patients using maintenance HD or CAPD, and similar trends were observed in male and female patients. Improvements in the lipid profile occurred independently of the time on dialysis prior to the commencement of EPO. We conclude that EPO treatment is associated with alterations in the lipid profile which may suggest a long-term improvement in the vascular morbidity of chronic renal failure. The causes of the improved lipids are not addressed by this study and may be equally due to a direct or secondary benefit of EPO therapy

The Energetics of Halogenated Ethylenes (Ethynes) and 1,3-Butadienes (Butadiynes): A Computational and Conceptual Study of Substituent Effects and “Dimerization”

The energetics of ethylenes and 1,3-butadienes may be interrelated by the reaction: RHC=CH2 + H2C=CHR\u27 → RHC=CH−CH=CHR\u27 + H2. Shown earlier to be nearly enthalpically thermoneutral for a variety of hydrocarbon cases, we are now interested in the related energetics of halogenated alkenes and alkynes. Using quantum chemical calculations, we have studied this as recast as the isodesmic reactions: 2(H2C=CHX) + H2C=CH−CH=CH2 → p,q-di-X-1,3-butadiene + 2H2C=CH2 2(HC≡CX) + HC≡C−C≡CH → di-X-butadiyne + 2HC≡CH. Here p,q- = 1,3-; 1,4- and 2,3- with X = F, Cl, Br, and I. The halogen and location-dependent deviations from near enthalpic thermoneutrality are discussed

A Brief Measure of Fidelity for Mindfulness Programs: Development and Evaluation of the Concise Fidelity for Mindfulness-Based Interventions Tool

BackgroundMindfulness research and clinical programs are widespread, and it is important that mindfulness-based interventions are delivered with fidelity, or as intended, across settings. The MBI:TAC is a comprehensive system for assessing teacher competence, yet it can be complex to implement. A standardized, simple fidelity/engagement tool to address treatment delivery is needed.ObjectiveWe describe the development, evaluation, and outcomes of a brief, practical tool for assessing fidelity and engagement in online mindfulness-based programs. The tool contains questions about session elements such as meditation guidance and group discussion, and questions about participant engagement and technology-based barriers to engagement.MethodsThe fidelity rating tool was developed and tested in OPTIMUM, Optimizing Pain Treatment in Medical settings Using Mindfulness. The OPTIMUM study is a 3-site pragmatic randomized trial of group medical visits and adapted mindfulness-based stress reduction for primary care patients with chronic low back pain, delivered online. Two trained study personnel independently rated 26 recorded OPTIMUM sessions to determine inter-rater reliability of the Concise Fidelity for Mindfulness-Based Interventions (CoFi-MBI) tool. Trained raters also completed the CoFi-MBI for 105 sessions. Raters provided qualitative data via optional open text fields within the tool.ResultsInter-rater agreement was 77-100% for presence of key session components, and 69-88% for Likert ratings of participant engagement and challenges related to technology, with discrepancies only occurring within 2 categories: ‘very much’ and ‘quite a bit’. Key session components occurred as intended in 94-100% of the 105 sessions, and participant engagement was rated as ‘very much’ or ‘quite a bit’ in 95% of the sessions. Qualitative analysis of rater comments revealed themes related to engagement challenges and technology failures.ConclusionThe CoFi-MBI provides a practical way to assess basic adherence to online delivery of mindfulness session elements, participant engagement, and extent of technology obstacles. Optional text can guide strategies to improve engagement and reduce technology barriers

Circulating 25-Hydroxyvitamin D Levels in Fully Breastfed Infants on Oral Vitamin D Supplementation

Objective. To examine the effectiveness of oral vitamin D3 (400 IU) supplementation on the nutritional vitamin D status of breastfeeding infants. Design. As part of a larger ongoing vitamin D RCT trial of lactating women, infants of mothers assigned to control received 1 drop of 400 IU vitamin D3/day starting at one month of age. Infant 25(OH)D levels (mean ± S.D.) were measured by RIA at visits 1, 4, and 7. Results. The infant mean ± S.D. 25(OH)D at baseline was 16.0 ±9.3 ng/mL (range 1.0–40.8; n = 33); 24 (72.7%) had baseline levels <20 ng/mL (consistent with deficiency). The mean levels increased to 43.6 ±14.1 (range 18.2–69.7) at 4 months and remained relatively unchanged at month 7: 42.5 ±12.1 ng/mL (range 18.9–67.2). The change in values between 1 and 4 months and 1 and 7 months was statistically significant (P ≤ .0001), and despite a decrease in dose per kilogram, values were not significantly different between months 4 and 7 (P = .66). Conclusions. Oral vitamin D3 supplementation as an oil emulsion was associated with significant and sustained increases in 25(OH)D from baseline in fully breastfeeding infants through 7 months

Advance care planning in chronic kidney disease: a survey of current practice in Australia

Aim: Advance care planning (ACP) in nephrology is widely advocated but not always implemented. The aims of this study were to describe current ACP practice and identify barriers/facilitators and perceived need for health professional education and chronic kidney disease (CKD)-specific approaches. Methods: An anonymous cross-sectional survey was administered online. Nephrology health professionals in Australia and New Zealandwere recruited via professional societies, email lists and nephrology conferences. Multiple regression explored the influence of respondents’ attributes on extent of involvement in ACP and willingness to engage in future. Results: A total of 375 respondents included nephrologists (23%), nurses (65%), social workers (4%) and others (8%) with 54% indicated that ACP at their workplace was performed ad hoc and 61% poorly. Perceived barriers included patient/family discomfort (84%), difficulty engaging families (83%), lack of clinician expertise (83%) and time (82%), health professional discomfort (72%), cultural/language barriers (65%), lack of private space (61%) and lack of formal policy/procedures (60%). Respondents overwhelmingly endorsed the need for more dialysis-specific ACP programs (96%) and education (95%). Whilst 85% thought ACP would be optimally performed by specially trained staff, comments emphasized that all clinicians should have a working proficiency. Respondents who were more willing to engage in future ACP tended to be non-physicians (odds ratio (OR) 4.96, 95% confidence intervals (CI) 1.74–14.07) and reported a greater need for CKD-specific ACP materials (OR 10.88, 95% CI 2.38–49.79). Conclusion: Advance care planning in nephrology needs support through education and CKD-specific resources. Endorsement by nephrologists is important. A multidisciplinary approach with a gradient of ACP expertise is also recommended

Tissue-specific calibration of extracellular matrix material properties by transforming growth factor-beta and Runx2 in bone is required for hearing

Publisher version: http://www.nature.com/embor/journal/v11/n10/full/embor2010135.htmlDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEPhysical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue-specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue-specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage-specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor-beta (TGFbeta)-responsive pathway that controls osteoblast differentiation. Deregulated TGFbeta or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2(+/-) mice, inhibition of TGFbeta signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue functio