The Habc Domain of the SNARE Vam3 Interacts with the HOPS Tethering Complex to Facilitate Vacuole Fusion*

PubMed Central

Lürick, Anna; Kuhlee, Anne; Bröcker, Cornelia; Kümmel, Daniel; Raunser, Stefan; Ungermann, Christian

2015-01-01

Membrane fusion at vacuoles requires a consecutive action of the HOPS tethering complex, which is recruited by the Rab GTPase Ypt7, and vacuolar SNAREs to drive membrane fusion. It is assumed that the Sec1/Munc18-like Vps33 within the HOPS complex is largely responsible for SNARE chaperoning. Here, we present direct evidence for HOPS binding to SNAREs and the Habc domain of the Vam3 SNARE protein, which may explain its function during fusion. We show that HOPS interacts strongly with the Vam3 Habc domain, assembled Q-SNAREs, and the R-SNARE Ykt6, but not the Q-SNARE Vti1 or the Vam3 SNARE domain. Electron microscopy combined with Nanogold labeling reveals that the binding sites for vacuolar SNAREs and the Habc domain are located in the large head of the HOPS complex, where Vps16 and Vps33 have been identified before. Competition experiments suggest that HOPS bound to the Habc domain can still interact with assembled Q-SNAREs, whereas Q-SNARE binding prevents recognition of the Habc domain. In agreement, membranes carrying Vam3ΔHabc fuse poorly unless an excess of HOPS is provided. These data suggest that the Habc domain of Vam3 facilitates the assembly of the HOPS/SNARE machinery at fusion sites and thus supports efficient membrane fusion. PMID:25564619

α-SNAP Interferes with the Zippering of the SNARE Protein Membrane Fusion Machinery

PubMed Central

Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M.; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

2014-01-01

Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. PMID:24778182

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yoosoo; Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791; Kim, Se-Hyun

Highlights: • Membrane fusion driven by SNARE complex is hindered by several polyphenols. • Distinctive inhibitory effect of each polyphenol on SNARE zippering in neuron was examined. • FRET between fluorescence protein-tagged SNAREs probed well SNARE zippering in PC12 cells. • Delphinidin and cyanidin inhibit N-terminal SNARE nucleation in Ca{sup 2+}-independent manner. • Myricetin inhibits Ca{sup 2+}-dependent transmembrane association of SNARE complex. - Abstract: Fusion of synaptic vesicles with the presynaptic plasma membrane in the neuron is mediated by soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor (SNARE) proteins. SNARE complex formation is a zippering-like process which initiates at the N-terminus andmore » proceeds to the C-terminal membrane-proximal region. Previously, we showed that this zippering-like process is regulated by several polyphenols, leading to the arrest of membrane fusion and the inhibition of neuroexocytosis. In vitro studies using purified SNARE proteins reconstituted in liposomes revealed that each polyphenol uniquely regulates SNARE zippering. However, the unique regulatory effect of each polyphenol in cells has not yet been examined. In the present study, we observed SNARE zippering in neuronal PC12 cells by measuring the fluorescence resonance energy transfer (FRET) changes of a cyan fluorescence protein (CFP) and a yellow fluorescence protein (YFP) fused to the N-termini or C-termini of SNARE proteins. We show that delphinidin and cyanidin inhibit the initial N-terminal nucleation of SNARE complex formation in a Ca{sup 2+}-independent manner, while myricetin inhibits Ca{sup 2+}-dependent transmembrane domain association of the SNARE complex in the cell. This result explains how polyphenols exhibit botulinum neurotoxin-like activity in vivo.« less

Energetics and Kinetics of trans-SNARE Zippering

NASA Astrophysics Data System (ADS)

Rebane, Aleksander A.; Shu, Tong; Krishnakumar, Shyam; Rothman, James E.; Zhang, Yongli

Synaptic exocytosis relies on assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins into a four-helix bundle to drive membrane fusion. Complementary SNAREs anchored to the synaptic vesicle (v-SNARE) and the plasma membrane (t-SNARE) associate from their N-termini, transiting a half-assembled intermediate (trans-SNARE), and ending at their C-termini with a rapid power stroke that leads to membrane fusion. Although cytosolic SNARE assembly has been characterized, it remains unknown how membranes modulate the energetics and kinetics of SNARE assembly. Here, we present optical tweezers measurements on folding of single membrane proteins in phospholipid bilayers. To our knowledge, this is the first such report. We measured the energetics, kinetics, and assembly intermediates of trans-SNAREs formed between a t-SNARE inserted into a bead-supported bilayer and a v-SNARE in a nanodisc. We found that the repulsive force of the apposed membranes increases the lifetime of the half-assembled intermediate. Our findings provide a single-molecule platform to study the regulation of trans-SNARE assembly by proteins that act on the half-assembled state, and thus reveal the mechanistic basis of the speed and high fidelity of synaptic transmission. This work was supported by US National Institutes of Health Grants F31 GM119312-01 (to A.A.R) and R01 GM093341 (to Y.Z.).

α-SNAP interferes with the zippering of the SNARE protein membrane fusion machinery.

PubMed

Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

2014-06-06

Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Munc13 homology domain-1 in CAPS/UNC31 mediates SNARE binding required for priming vesicle exocytosis.

PubMed

Khodthong, Chuenchanok; Kabachinski, Greg; James, Declan J; Martin, Thomas F J

2011-08-03

Neuropeptide and peptide hormone secretion from neural and endocrine cells occurs by Ca(2+)-triggered dense-core vesicle exocytosis. The membrane fusion machinery consisting of vesicle and plasma membrane SNARE proteins needs to be assembled for Ca(2+)-triggered vesicle exocytosis. The related Munc13 and CAPS/UNC31 proteins that prime vesicle exocytosis are proposed to promote SNARE complex assembly. CAPS binds SNARE proteins and stimulates SNARE complex formation on liposomes, but the relevance of SNARE binding to CAPS function in cells had not been determined. Here we identify a core SNARE-binding domain in CAPS as corresponding to Munc13 homology domain-1 (MHD1). CAPS lacking a single helix in MHD1 was unable to bind SNARE proteins or to support the Ca(2+)-triggered exocytosis of either docked or newly arrived dense-core vesicles. The results show that MHD1 is a SNARE-binding domain and that SNARE protein binding is essential for CAPS function in dense-core vesicle exocytosis. Copyright © 2011 Elsevier Inc. All rights reserved.

The binding of Varp to VAMP7 traps VAMP7 in a closed, fusogenically inactive conformation

PubMed Central

Schäfer, Ingmar B.; Hesketh, Geoffrey G.; Bright, Nicholas A.; Gray, Sally R.; Pryor, Paul R.; Evans, Philip R; Luzio, J. Paul; Owen, David J.

2012-01-01

SNAREs provide energy and specificity to membrane fusion events. Fusogenic trans-SNARE complexes are assembled from Q-SNAREs embedded in one membrane and an R–SNARE embedded in the other. Regulation of membrane fusion events is crucial for intracellular trafficking. We identify the endosomal protein Varp as an R-SNARE-binding regulator of SNARE complex formation. Varp co-localises with and binds to VAMP7, an R-SNARE involved in both endocytic and secretory pathways. We present the structure of the second ankyrin repeat domain of mammalian Varp in complex with the cytosolic portion of VAMP7. The VAMP7 SNARE motif is trapped between Varp and the VAMP7 longin domain and hence Varp kinetically inhibits VAMP7’s ability to form SNARE complexes. This inhibition will be increased when Varp can also bind to other proteins present on the same membrane as the VAMP7 such as Rab32:GTP. PMID:23104059

Dilation of fusion pores by crowding of SNARE proteins

PubMed Central

Wu, Zhenyong; Bello, Oscar D; Thiyagarajan, Sathish; Auclair, Sarah Marie; Vennekate, Wensi; Krishnakumar, Shyam S; O'Shaughnessy, Ben; Karatekin, Erdem

2017-01-01

Hormones and neurotransmitters are released through fluctuating exocytotic fusion pores that can flicker open and shut multiple times. Cargo release and vesicle recycling depend on the fate of the pore, which may reseal or dilate irreversibly. Pore nucleation requires zippering between vesicle-associated v-SNAREs and target membrane t-SNAREs, but the mechanisms governing the subsequent pore dilation are not understood. Here, we probed the dilation of single fusion pores using v-SNARE-reconstituted ~23-nm-diameter discoidal nanolipoprotein particles (vNLPs) as fusion partners with cells ectopically expressing cognate, 'flipped' t-SNAREs. Pore nucleation required a minimum of two v-SNAREs per NLP face, and further increases in v-SNARE copy numbers did not affect nucleation rate. By contrast, the probability of pore dilation increased with increasing v-SNARE copies and was far from saturating at 15 v-SNARE copies per face, the NLP capacity. Our experimental and computational results suggest that SNARE availability may be pivotal in determining whether neurotransmitters or hormones are released through a transient ('kiss and run') or an irreversibly dilating pore (full fusion). DOI: http://dx.doi.org/10.7554/eLife.22964.001 PMID:28346138

A prospective comparison of cold snare polypectomy using traditional or dedicated cold snares for the resection of small sessile colorectal polyps

PubMed Central

Dwyer, Jeremy P.; Tan, Jonathan Y. C.; Urquhart, Paul; Secomb, Robyn; Bunn, Catherine; Reynolds, John; La Nauze, Richard; Kemp, William; Roberts, Stuart; Brown, Gregor

2017-01-01

Background and study aims  The evidence for efficacy and safety of cold snare polypectomy is limited. The aim of this study was to assess the completeness of resection and safety of cold snare polypectomy, using either traditional or dedicated cold snares. Patients and methods  This was a prospective, non-randomized study performed at a single tertiary hospital. Adult patients with at least one colorectal polyp (size ≤ 10 mm) removed by cold snare were included. In the first phase, all patients had polyps removed by traditional snare without diathermy. In the second phase, all patients had polyps removed by dedicated cold snare. Complete endoscopic resection was determined from histological examination of quadrantic polypectomy margin biopsies. Immediate or delayed bleeding within 2 weeks was recorded. Results  In total, 181 patients with 299 eligible polyps (n = 93 (173 polyps) traditional snare group, n = 88 (126 polyps) dedicated cold snare group) were included. Patient demographics and procedure indications were similar between groups. Mean polyp size was 6 mm in both groups ( P  = 0.25). Complete polyp resection was 165 /173 (95.4 %; 95 %CI 90.5 – 97.6 %) in the traditional snare group and 124/126 (98.4 %; 95 %CI 93.7 – 99.6 %) in the dedicated cold snare group ( P  = 0.16). Serrated polyps, compared with adenomatous polyps, had a higher rate of incomplete resection (7 % vs. 2 %, P  = 0.03). There was no statistically significant difference in the rate of immediate bleeding (3 % vs. 1 %, P  = 0.41) and there were no delayed hemorrhages or perforations. Conclusions  Cold snare polypectomy is effective and safe for the complete endoscopic resection of small (≤ 10 mm) colorectal polyps with either traditional or dedicated cold snares. PMID:29250580

Novel interactions of CAPS (Ca2+-dependent activator protein for secretion) with the three neuronal SNARE proteins required for vesicle fusion.

PubMed

Daily, Neil J; Boswell, Kristin L; James, Declan J; Martin, Thomas F J

2010-11-12

CAPS (aka CADPS) is required for optimal vesicle exocytosis in neurons and endocrine cells where it functions to prime the exocytic machinery for Ca(2+)-triggered fusion. Fusion is mediated by trans complexes of the SNARE proteins VAMP-2, syntaxin-1, and SNAP-25 that bridge vesicle and plasma membrane. CAPS promotes SNARE complex formation on liposomes, but the SNARE binding properties of CAPS are unknown. The current work revealed that CAPS exhibits high affinity binding to syntaxin-1 and SNAP-25 and moderate affinity binding to VAMP-2. CAPS binding is specific for a subset of exocytic SNARE protein isoforms and requires membrane integration of the SNARE proteins. SNARE protein binding by CAPS is novel and mediated by interactions with the SNARE motifs in the three proteins. The C-terminal site for CAPS binding on syntaxin-1 does not overlap the Munc18-1 binding site and both proteins can co-reside on membrane-integrated syntaxin-1. As expected for a C-terminal binding site on syntaxin-1, CAPS stimulates SNARE-dependent liposome fusion with N-terminal truncated syntaxin-1 but exhibits impaired activity with C-terminal syntaxin-1 mutants. Overall the results suggest that SNARE complex formation promoted by CAPS may be mediated by direct interactions of CAPS with each of the three SNARE proteins required for vesicle exocytosis.

Novel Interactions of CAPS (Ca2+-dependent Activator Protein for Secretion) with the Three Neuronal SNARE Proteins Required for Vesicle Fusion*

PubMed Central

Daily, Neil J.; Boswell, Kristin L.; James, Declan J.; Martin, Thomas F. J.

2010-01-01

CAPS (aka CADPS) is required for optimal vesicle exocytosis in neurons and endocrine cells where it functions to prime the exocytic machinery for Ca2+-triggered fusion. Fusion is mediated by trans complexes of the SNARE proteins VAMP-2, syntaxin-1, and SNAP-25 that bridge vesicle and plasma membrane. CAPS promotes SNARE complex formation on liposomes, but the SNARE binding properties of CAPS are unknown. The current work revealed that CAPS exhibits high affinity binding to syntaxin-1 and SNAP-25 and moderate affinity binding to VAMP-2. CAPS binding is specific for a subset of exocytic SNARE protein isoforms and requires membrane integration of the SNARE proteins. SNARE protein binding by CAPS is novel and mediated by interactions with the SNARE motifs in the three proteins. The C-terminal site for CAPS binding on syntaxin-1 does not overlap the Munc18-1 binding site and both proteins can co-reside on membrane-integrated syntaxin-1. As expected for a C-terminal binding site on syntaxin-1, CAPS stimulates SNARE-dependent liposome fusion with N-terminal truncated syntaxin-1 but exhibits impaired activity with C-terminal syntaxin-1 mutants. Overall the results suggest that SNARE complex formation promoted by CAPS may be mediated by direct interactions of CAPS with each of the three SNARE proteins required for vesicle exocytosis. PMID:20826818

Comparison of three patent foramen ovale closure devices in a randomized trial (Amplatzer versus CardioSEAL-STARflex versus Helex occluder).

PubMed

Taaffe, Margaret; Fischer, Evelyn; Baranowski, Andreas; Majunke, Nicolas; Heinisch, Corinna; Leetz, Michaela; Hein, Ralph; Bayard, Yves; Büscheck, Franziska; Reschke, Madlen; Hoffmann, Ilona; Wunderlich, Nina; Wilson, Neil; Sievert, Horst

2008-05-01

This randomized trial compared procedural complications and 30-day clinical outcomes of 3 patent foramen ovale (PFO) closure devices (Amplatzer, Helex, and CardioSEAL-STARflex). It examined 660 patients (361 men, 299 women, mean age 49.3+/-1.9 years), with 220 patients per group. All patients had a history of paradoxical embolism. All PFO closures were successful technically. Exchange of devices for others was most frequently required for the Helex occluder (7 of 220) and 2 of 220 in either of the other groups. Three device embolizations in the Helex group were retrieved and replaced successfully. One patient with a Helex occluder developed a transient ischemic attack and recovered without treatment. A hemopericardium in that group was punctured without affecting the device. One tamponade in the Amplatzer group required surgical device explantation. In 8 of 660 patients in the CardioSEAL-STARflex group, thrombi resolved after anticoagulation. Sixteen patients (11 in the CardioSEAL-STARflex group, 3 in the Amplatzer group, and 2 in the Helex group) had episodes of atrial fibrillation. PFOs were closed completely in 143 of 220 patients (65%) in the Amplatzer group, 116 of 220 patients (52.7%) in the Helex group, and 137 of 220 patients (62.3%) in the CardioSEAL-STARflex group at 30 days with significant differences between the Helex and Amplatzer occluders (p=0.0005) and the Helex and CardioSEAL-STARflex occluders (p=0.0003). PFO closure can be performed safely with each device. In conclusion, the Helex occluder embolized more frequently. Device thrombus formation and paroxysmal atrial fibrillation were more common with the CardioSEAL-STARflex occluder.

Amplatzer Vascular Plugs Versus Coils for Embolization of Pulmonary Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia.

PubMed

Tau, Noam; Atar, Eliyahu; Mei-Zahav, Meir; Bachar, Gil N; Dagan, Tamir; Birk, Einat; Bruckheimer, Elchanan

2016-08-01

Coil embolization of pulmonary arteriovenous malformations (PAVMs) has a high re-canalization/re-perfusion rate. Embolization with Amplatzer plugs has been previously described, but the long-term efficacy is not established. This study reports the experience of a referral medical center with the use of coils and Amplatzer plugs for treating PAVMs in patients with hereditary hemorrhagic telangiectasia. The study was approved by the Institutional Review Board with waiver of informed consent. The cohort included all patients who underwent PAVM embolization in 2004-2014 for whom follow-up imaging scans were available. The medical files were retrospectively reviewed for background data, embolization method (coils, Amplatzer plugs, both), and complications. Re-canalization of treated PAVMs was assessed from intrapulmonary angiograms (following percutaneous procedures) or computed tomography angiograms. Fisher's exact test and Pearson Chi-squared test or t test were used for statistical analysis, with significance at p < 0.05. 16 patients met the study criteria. Imaging scans were available for 63 of the total 110 PAVMs treated in 41 procedures. Coils were used for embolization in 37 PAVMs, Amplatzer plugs in 21, and both in five. Median follow-up time was 7.7 years (range 1.4-18.9). Re-canalization was detected in seven vessels, all treated with coils; there were no cases of re-canalization in plug-occluded vessels (p = 0.0413). The use of Amplatzer plugs for the embolization of PAVMs in patients with hemorrhagic telangiectasia is associated with a significantly lower rate of re-canalization of feeding vessels than coils. Long-term prospective studies are required to confirm these findings.

Amplatzer Vascular Plugs Versus Coils for Embolization of Pulmonary Arteriovenous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tau, Noam, E-mail: taunoam@gmail.com; Atar, Eliyahu; Mei-Zahav, Meir

PurposeCoil embolization of pulmonary arteriovenous malformations (PAVMs) has a high re-canalization/re-perfusion rate. Embolization with Amplatzer plugs has been previously described, but the long-term efficacy is not established. This study reports the experience of a referral medical center with the use of coils and Amplatzer plugs for treating PAVMs in patients with hereditary hemorrhagic telangiectasia.MethodsThe study was approved by the Institutional Review Board with waiver of informed consent. The cohort included all patients who underwent PAVM embolization in 2004–2014 for whom follow-up imaging scans were available. The medical files were retrospectively reviewed for background data, embolization method (coils, Amplatzer plugs, both),more » and complications. Re-canalization of treated PAVMs was assessed from intrapulmonary angiograms (following percutaneous procedures) or computed tomography angiograms. Fisher’s exact test and Pearson Chi-squared test or t test were used for statistical analysis, with significance at p < 0.05.Results16 patients met the study criteria. Imaging scans were available for 63 of the total 110 PAVMs treated in 41 procedures. Coils were used for embolization in 37 PAVMs, Amplatzer plugs in 21, and both in five. Median follow-up time was 7.7 years (range 1.4–18.9). Re-canalization was detected in seven vessels, all treated with coils; there were no cases of re-canalization in plug-occluded vessels (p = 0.0413).ConclusionThe use of Amplatzer plugs for the embolization of PAVMs in patients with hemorrhagic telangiectasia is associated with a significantly lower rate of re-canalization of feeding vessels than coils. Long-term prospective studies are required to confirm these findings.« less

[Percutaneous closure of the patent ductus arteriosus in children with the Amplatzer Duct Occluder II].

PubMed

Parra-Bravo, José Rafael; Osuna-Izaguirre, Manuel Alfredo; Beirana-Palencia, Luisa; Gálvez-Cancino, Franco; Martínez-Monterrosas, Christian; Lazo-Cárdenas, César; Reyes-Vargas, César

2014-01-01

In the last decades, several devices have been used for the percutaneous closure of patent ductus arteriosus, with its own limitations and risks. The Amplatzer Duct Occluder II has been designed to overcome those limitations and reduce risks. We described our initial series of patients who underwent percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder II, emphasis on the technical aspects of the procedure. We reviewed the clinical records of 9 patients with patent ductus arteriosus who underwent percutaneous closure with the Amplatzer Duct Occluder II. Median age was 24 months (range 8-51 months) and the median weight was 10.7kg (range 6-16.3kg). The minimal ductus arteriosus diameter was 2.7mm (1-5mm). Implantation was successful in all cases. The devices most commonly used (33.3%) were the dimensions 4-4mm (3 patients), in 2 patients were used 3-4mm and in the rest of the patients were employed occluder other sizes. Four cases showed slight residual flow immediately after implantation. Total closure was achieved in 24h in 8 of 9 patients (89%). There was no embolization of the occluder or deaths during the procedure and we only observed one minor complication. The Amplatzer Duct Occluder II in this series was effective in 89% of the patients at 24hs after the procedure and 100% follow-up. The implantation was safe and no major complications were observed. The occlusion rate is comparable to those reported for the Amplatzer Duct Occluder I. Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

[Right patent ductus arteriosus with an ipsilateral aortic arch: percutaneous closure with amplatzer devices].

PubMed

Santiago, Justo; Acuña, Manuel; Arispe, Elizabeth; Camargo, Ronaldo; Neves, Juliana; Arnoni, Daniel; Fontes, Valmir F; Pedra, Carlos A

2007-03-01

The association of a right aortic arch with an ipsilateral patent ductus arteriosus is rare, especially when there are no other intracardiac anomalies. We report three female patients aged 26, 35 and 9 years with this combination in whom previous attempts at surgical closure by thoracotomy and sternotomy were unsuccessful and who subsequently underwent successful percutaneous closure of the defects using Amplatzer devices. In two patients, although angiography demonstrated the presence of type-A patent ductus arteriosus, it was not possible to determine the minimum diameter accurately and it was necessary to measure it using a sizing balloon. An Amplatzer duct occluder was used in two patients and an Amplatzer muscular ventricular septal defect occluder, in the other. In all patients, full closure was confirmed in the catheterization laboratory and the patients were discharged on the same day with no complications. Percutaneous closure of a right patent ductus arteriosus associated with a right aortic arch is feasible, safe and effective.

[Percutaneous closure of ductus arteriosus and muscular ventricular defect with amplatzer occluder in a patient with severe pulmonary hypertension].

PubMed

García-Montes, José Antonio; Zabal Cerdeira, Carlos; Calderón-Colmenero, Juan; Espínola, Nilda; Fernández de la Reguera, Guillermo; Buendía Hernández, Alfonso

2005-01-01

Surgical treatment of multiple muscular ventricular septal defects with associated lesions and severe pulmonary hypertension has a high morbility and mortality. Closure of these defects by the Amplatzer muscular VSD occluder is an alternative to surgery, avoiding the need of cardiopulmonary bypass. We present the case of a 38 year-old woman with signs of heart failure in NYHA functional class IV, with two muscular ventricular septal defects, patent ductus arteriosus and severe pulmonary hypertension, that were treated with three Amplatzer muscular VSD occluders, with significant reduction of pulmonary pressure and functional class improvement.

Calcium-dependent regulation of SNARE-mediated membrane fusion by calmodulin.

PubMed

Di Giovanni, Jerome; Iborra, Cécile; Maulet, Yves; Lévêque, Christian; El Far, Oussama; Seagar, Michael

2010-07-30

Neuroexocytosis requires SNARE proteins, which assemble into trans complexes at the synaptic vesicle/plasma membrane interface and mediate bilayer fusion. Ca(2+) sensitivity is thought to be conferred by synaptotagmin, although the ubiquitous Ca(2+)-effector calmodulin has also been implicated in SNARE-dependent membrane fusion. To examine the molecular mechanisms involved, we examined the direct action of calmodulin and synaptotagmin in vitro, using fluorescence resonance energy transfer to assay lipid mixing between target- and vesicle-SNARE liposomes. Ca(2+)/calmodulin inhibited SNARE assembly and membrane fusion by binding to two distinct motifs located in the membrane-proximal regions of VAMP2 (K(D) = 500 nm) and syntaxin 1 (K(D) = 2 microm). In contrast, fusion was increased by full-length synaptotagmin 1 anchored in vesicle-SNARE liposomes. When synaptotagmin and calmodulin were combined, synaptotagmin overcame the inhibitory effects of calmodulin. Furthermore, synaptotagmin displaced calmodulin binding to target-SNAREs. These findings suggest that two distinct Ca(2+) sensors act antagonistically in SNARE-mediated fusion.

The Multifaceted Role of SNARE Proteins in Membrane Fusion

PubMed Central

Han, Jing; Pluhackova, Kristyna; Böckmann, Rainer A.

2017-01-01

Membrane fusion is a key process in all living organisms that contributes to a variety of biological processes including viral infection, cell fertilization, as well as intracellular transport, and neurotransmitter release. In particular, the various membrane-enclosed compartments in eukaryotic cells need to exchange their contents and communicate across membranes. Efficient and controllable fusion of biological membranes is known to be driven by cooperative action of SNARE proteins, which constitute the central components of the eukaryotic fusion machinery responsible for fusion of synaptic vesicles with the plasma membrane. During exocytosis, vesicle-associated v-SNARE (synaptobrevin) and target cell-associated t-SNAREs (syntaxin and SNAP-25) assemble into a core trans-SNARE complex. This complex plays a versatile role at various stages of exocytosis ranging from the priming to fusion pore formation and expansion, finally resulting in the release or exchange of the vesicle content. This review summarizes current knowledge on the intricate molecular mechanisms underlying exocytosis triggered and catalyzed by SNARE proteins. Particular attention is given to the function of the peptidic SNARE membrane anchors and the role of SNARE-lipid interactions in fusion. Moreover, the regulatory mechanisms by synaptic auxiliary proteins in SNARE-driven membrane fusion are briefly outlined. PMID:28163686

The Multifaceted Role of SNARE Proteins in Membrane Fusion.

PubMed

Han, Jing; Pluhackova, Kristyna; Böckmann, Rainer A

2017-01-01

Membrane fusion is a key process in all living organisms that contributes to a variety of biological processes including viral infection, cell fertilization, as well as intracellular transport, and neurotransmitter release. In particular, the various membrane-enclosed compartments in eukaryotic cells need to exchange their contents and communicate across membranes. Efficient and controllable fusion of biological membranes is known to be driven by cooperative action of SNARE proteins, which constitute the central components of the eukaryotic fusion machinery responsible for fusion of synaptic vesicles with the plasma membrane. During exocytosis, vesicle-associated v-SNARE (synaptobrevin) and target cell-associated t-SNAREs (syntaxin and SNAP-25) assemble into a core trans-SNARE complex. This complex plays a versatile role at various stages of exocytosis ranging from the priming to fusion pore formation and expansion, finally resulting in the release or exchange of the vesicle content. This review summarizes current knowledge on the intricate molecular mechanisms underlying exocytosis triggered and catalyzed by SNARE proteins. Particular attention is given to the function of the peptidic SNARE membrane anchors and the role of SNARE-lipid interactions in fusion. Moreover, the regulatory mechanisms by synaptic auxiliary proteins in SNARE-driven membrane fusion are briefly outlined.

Interactions within the yeast t-SNARE Sso1p that control SNARE complex assembly.

PubMed

Munson, M; Chen, X; Cocina, A E; Schultz, S M; Hughson, F M

2000-10-01

In the eukaryotic secretory and endocytic pathways, transport vesicles shuttle cargo among intracellular organelles and to and from the plasma membrane. Cargo delivery entails fusion of the transport vesicle with its target, a process thought to be mediated by membrane bridging SNARE protein complexes. Temporal and spatial control of intracellular trafficking depends in part on regulating the assembly of these complexes. In vitro, SNARE assembly is inhibited by the closed conformation adopted by the syntaxin family of SNAREs. To visualize this closed conformation directly, the X-ray crystal structure of a yeast syntaxin, Sso1p, has been determined and refined to 2.1 A resolution. Mutants designed to destabilize the closed conformation exhibit accelerated rates of SNARE assembly. Our results provide insight into the mechanism of SNARE assembly and its intramolecular and intermolecular regulation.

Heat exchanger bypass system for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A heat exchanger bypass system for an absorption refrigeration system is disclosed. The bypass system operates to pass strong solution from the generator around the heat exchanger to the absorber of the absorption refrigeration system when strong solution builds up in the generator above a selected level indicative of solidification of strong solution in the heat exchanger or other such blockage. The bypass system includes a bypass line with a gooseneck located in the generator for controlling flow of strong solution into the bypass line and for preventing refrigerant vapor in the generator from entering the bypass line during normal operation of the refrigeration system. Also, the bypass line includes a trap section filled with liquid for providing a barrier to maintain the normal pressure difference between the generator and the absorber even when the gooseneck of the bypass line is exposed to refrigerant vapor in the generator. Strong solution, which may accumulate in the trap section of the bypass line, is diluted, to prevent solidification, by supplying weak solution to the trap section from a purge system for the absorption refrigeration system.

v-SNAREs control exocytosis of vesicles from priming to fusion.

PubMed

Borisovska, Maria; Zhao, Ying; Tsytsyura, Yaroslav; Glyvuk, Nataliya; Takamori, Shigeo; Matti, Ulf; Rettig, Jens; Südhof, Thomas; Bruns, Dieter

2005-06-15

SNARE proteins (soluble NSF-attachment protein receptors) are thought to be central components of the exocytotic mechanism in neurosecretory cells, but their precise function remained unclear. Here, we show that each of the vesicle-associated SNARE proteins (v-SNARE) of a chromaffin granule, synaptobrevin II or cellubrevin, is sufficient to support Ca(2+)-dependent exocytosis and to establish a pool of primed, readily releasable vesicles. In the absence of both proteins, secretion is abolished, without affecting biogenesis or docking of granules indicating that v-SNAREs are absolutely required for granule exocytosis. We find that synaptobrevin II and cellubrevin differentially control the pool of readily releasable vesicles and show that the v-SNARE's amino terminus regulates the vesicle's primed state. We demonstrate that dynamics of fusion pore dilation are regulated by v-SNAREs, indicating their action throughout exocytosis from priming to fusion of vesicles.

Complexin and Ca2+ stimulate SNARE-mediated membrane fusion

PubMed Central

Yoon, Tae-Young; Lu, Xiaobind; Diao, Jiajie; Lee, Soo-Min; Ha, Taekjip; Shin, Yeon-Kyun

2008-01-01

Ca2+-triggered, synchronized synaptic vesicle fusion underlies interneuronal communication. Complexin is a major binding partner of the SNARE complex, the core fusion machinery at the presynapse. The physiological data on complexin, however, have been at odds with each other, making delineation of its molecular function difficult. Here we report direct observation of two-faceted functions of complexin using the single-vesicle fluorescence fusion assay and EPR. We show that complexin I has two opposing effects on trans-SNARE assembly: inhibition of SNARE complex formation and stabilization of assembled SNARE complexes. Of note, SNARE-mediated fusion is markedly stimulated by complexin, and it is further accelerated by two orders of magnitude in response to an externally applied Ca2+ wave. We suggest that SNARE complexes, complexins and phospholipids collectively form a complex substrate for Ca2+ and Ca2+-sensing fusion effectors in neurotransmitter release. PMID:18552825

SNARE interactions in membrane trafficking: a perspective from mammalian central synapses.

PubMed

Kavalali, Ege T

2002-10-01

SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) are a large family of proteins that are present on all organelles involved in intracellular vesicle trafficking and secretion. The interaction of complementary SNAREs found on opposing membranes presents an attractive lock-and-key mechanism, which may underlie the specificity of vesicle trafficking. Moreover, formation of the tight complex between a vesicle membrane SNARE and corresponding target membrane SNAREs could drive membrane fusion. In synapses, this tight complex, also referred to as the synaptic core complex, is essential for neurotransmitter release. However, recent observations in knockout mice lacking major synaptic SNAREs challenge the prevailing notion on the executive role of these proteins in fusion and open up several questions about their exact role(s) in neurotransmitter release. Persistence of a form of regulated neurotransmitter release in these mutant mice also raises the possibility that other cognate or non-cognate SNAREs may partially compensate for the loss of a particular SNARE. Future analysis of SNARE function in central synapses will also have implications for the role of these molecules in other vesicle trafficking events such as endocytosis and vesicle replenishment. Such analysis can provide a molecular basis for synaptic processes including certain forms of short-term synaptic plasticity. Copyright 2002 Wiley Periodicals, Inc.

The structure of the yeast plasma membrane SNARE complex reveals destabilizing water-filled cavities.

PubMed

Strop, Pavel; Kaiser, Stephen E; Vrljic, Marija; Brunger, Axel T

2008-01-11

SNARE proteins form a complex that leads to membrane fusion between vesicles, organelles, and plasma membrane in all eukaryotic cells. We report the 1.7A resolution structure of the SNARE complex that mediates exocytosis at the plasma membrane in the yeast Saccharomyces cerevisiae. Similar to its neuronal and endosomal homologues, the S. cerevisiae SNARE complex forms a parallel four-helix bundle in the center of which is an ionic layer. The S. cerevisiae SNARE complex exhibits increased helix bending near the ionic layer, contains water-filled cavities in the complex core, and exhibits reduced thermal stability relative to mammalian SNARE complexes. Mutagenesis experiments suggest that the water-filled cavities contribute to the lower stability of the S. cerevisiae complex.

Arabidopsis SNAREs SYP61 and SYP121 coordinate the trafficking of plasma membrane aquaporin PIP2;7 to modulate the cell membrane water permeability.

PubMed

Hachez, Charles; Laloux, Timothée; Reinhardt, Hagen; Cavez, Damien; Degand, Hervé; Grefen, Christopher; De Rycke, Riet; Inzé, Dirk; Blatt, Michael R; Russinova, Eugenia; Chaumont, François

2014-07-01

Plant plasma membrane intrinsic proteins (PIPs) are aquaporins that facilitate the passive movement of water and small neutral solutes through biological membranes. Here, we report that post-Golgi trafficking of PIP2;7 in Arabidopsis thaliana involves specific interactions with two syntaxin proteins, namely, the Qc-SNARE SYP61 and the Qa-SNARE SYP121, that the proper delivery of PIP2;7 to the plasma membrane depends on the activity of the two SNAREs, and that the SNAREs colocalize and physically interact. These findings are indicative of an important role for SYP61 and SYP121, possibly forming a SNARE complex. Our data support a model in which direct interactions between specific SNARE proteins and PIP aquaporins modulate their post-Golgi trafficking and thus contribute to the fine-tuning of the water permeability of the plasma membrane. © 2014 American Society of Plant Biologists. All rights reserved.

SNARE proteins synaptobrevin, SNAP-25 and syntaxin are involved in rapid and slow endocytosis at synapses

PubMed Central

Xu, Jianhua; Luo, Fujun; Zhang, Zhen; Xue, Lei; Wu, Xinsheng; Chiang, Hsueh-Cheng; Shin, Wonchul; Wu, Ling-Gang

2013-01-01

Rapid endocytosis, which takes only a few seconds, is widely observed in secretory cells. Although it is more efficient in recycling vesicles than slow clathrin-mediated endocytosis, its underlying mechanism, thought to be clathrin-independent, is largely unclear. Here we reported that cleavage of three SNARE proteins essential for exocytosis, including synaptobrevin, SNAP-25 and syntaxin, inhibited rapid endocytosis at the calyx of Held nerve terminal, suggesting the involvement of three SNARE proteins in rapid endocytosis. These SNARE proteins were also involved in slow endocytosis. In addition, SNAP-25 and syntaxin facilitated vesicle mobilization to the readily releasable pool, likely via their roles in endocytosis and/or exocytosis. We concluded that both rapid and slow endocytosis share the involvement of SNARE proteins. The dual role of three SNARE proteins in exo- and endocytosis suggests that SNARE proteins may be molecular substrates contributing to the exo-endocytosis coupling, which maintains exocytosis in secretory cells. PMID:23643538

Retrieval of large Occlutech Figula Flex septal defect occluders using a commercially available bioptome: proof of concept.

PubMed

Georgiev, Stanimir; Tanase, Daniel; Genz, Thomas; Ewert, Peter; Naumann, Susanne; Pozza, Robert Dalla; Eicken, Andreas

2018-07-01

This study aimed to develop a method for retrieval of the new meshed nitinol atrial septal defect occluders - Ceraflex and Occlutech. The newly developed atrial septal defect occluders have potential benefits considering implantation, but concerns regarding their removal in case of embolisation have been raised. Over 21 years, 1449 patients underwent interventional atrial septal defect occlusion in our institution. We reviewed the cases of embolisation of the device, developed a strategy for device removal, and tested it on the benchside and in animal tests. In 11 patients (0.8%), the intended atrial septal defect occlusion was complicated by an embolisation of the device. In contrast to the Amplatzer septal occluders, retrieval of Occlutech devices larger than 16 mm with snare techniques was impossible. In benchside tests, this was confirmed and a new method for removal of large meshed devices was developed. This involved the commercially available Maslanka® biopsy forceps. The feasibility of this technique in vivo was tested in a pig model. During animal tests, using the Maslanka biopsy forceps it was possible to interventionally retrieve embolised Ceraflex and Occlutech devices of different sizes - 10, 16, 30, and 40 mm - into a 12-F sheath. It was impossible to retrieve Occlutech and Ceraflex devices larger than 16 mm into a large sheath in vivo and during benchside tests. However, this was feasible on the bench and in vivo using the Maslanka biopsy forceps even with the largest available devices.

Experimental estimation of snare detectability for robust threat monitoring.

PubMed

O'Kelly, Hannah J; Rowcliffe, J Marcus; Durant, Sarah; Milner-Gulland, E J

2018-02-01

Hunting with wire snares is rife within many tropical forest systems, and constitutes one of the severest threats to a wide range of vertebrate taxa. As for all threats, reliable monitoring of snaring levels is critical for assessing the relative effectiveness of management interventions. However, snares pose a particular challenge in terms of tracking spatial or temporal trends in their prevalence because they are extremely difficult to detect, and are typically spread across large, inaccessible areas. As with cryptic animal targets, any approach used to monitor snaring levels must address the issue of imperfect detection, but no standard method exists to do so. We carried out a field experiment in Keo Seima Wildlife Reserve in eastern Cambodia with the following objectives: (1) To estimate the detection probably of wire snares within a tropical forest context, and to investigate how detectability might be affected by habitat type, snare type, or observer. (2) To trial two sets of sampling protocols feasible to implement in a range of challenging field conditions. (3) To conduct a preliminary assessment of two potential analytical approaches to dealing with the resulting snare encounter data. We found that although different observers had no discernible effect on detection probability, detectability did vary between habitat type and snare type. We contend that simple repeated counts carried out at multiple sites and analyzed using binomial mixture models could represent a practical yet robust solution to the problem of monitoring snaring levels both inside and outside of protected areas. This experiment represents an important first step in developing improved methods of threat monitoring, and such methods are greatly needed in southeast Asia, as well as in as many other regions.

In vitro assay using engineered yeast vacuoles for neuronal SNARE-mediated membrane fusion

PubMed Central

Ko, Young-Joon; Lee, Miriam; Kang, KyeongJin; Song, Woo Keun; Jun, Youngsoo

2014-01-01

Intracellular membrane fusion requires not only SNARE proteins but also other regulatory proteins such as the Rab and Sec1/Munc18 (SM) family proteins. Although neuronal SNARE proteins alone can drive the fusion between synthetic liposomes, it remains unclear whether they are also sufficient to induce the fusion of biological membranes. Here, through the use of engineered yeast vacuoles bearing neuronal SNARE proteins, we show that neuronal SNAREs can induce membrane fusion between yeast vacuoles and that this fusion does not require the function of the Rab protein Ypt7p or the SM family protein Vps33p, both of which are essential for normal yeast vacuole fusion. Although excess vacuolar SNARE proteins were also shown to mediate Rab-bypass fusion, this fusion required homotypic fusion and vacuole protein sorting complex, which bears Vps33p and was accompanied by extensive membrane lysis. We also show that this neuronal SNARE-driven vacuole fusion can be stimulated by the neuronal SM protein Munc18 and blocked by botulinum neurotoxin serotype E, a well-known inhibitor of synaptic vesicle fusion. Taken together, our results suggest that neuronal SNARE proteins are sufficient to induce biological membrane fusion, and that this new assay can be used as a simple and complementary method for investigating synaptic vesicle fusion mechanisms. PMID:24821814

Identification of SNAREs that mediate zymogen granule exocytosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickett, James A.; Campos-Toimil, Manuel; Thomas, Paul

2007-08-03

A secretagogue-stimulated pancreatic acinar cell releases digestive enzymes from its apical pole. We attempted to identify the SNAREs involved in zymogen granule exocytosis. Antibodies against syntaxins 2 and 3, SNAP-23 and VAMP 8, and the corresponding recombinant SNAREs, inhibited amylase secretion from streptolysin O-permeabilised acini; other anti-SNARE antibodies and SNAREs had no effect. Botulinum neurotoxin C, which cleaved syntaxin 2 and (to a lesser extent) syntaxin 3, but not syntaxins 4, 7 or 8, also inhibited exocytosis. We propose that syntaxin 2, SNAP-23 and VAMP 8 mediate primary granule-plasma membrane fusion. Syntaxin 3 may be involved in secondary granule-granule fusion.

Amplatzer angled duct occluder for closure of patent ductus arteriosus larger than the aorta in an infant.

PubMed

Vijayalakshmi, I B; Chitra, N; Rajasri, R; Prabhudeva, A N

2005-01-01

Transcatheter closure of patent ductus arteriosus (PDA) by Amplatzer duct occluder is the treatment of choice. However, closure of very large ducts in infants with low weight is a challenge for the interventionalist because a large device may obstruct the aorta or left pulmonary artery. Difficulty is also encountered in advancing the device around the curve of the right ventricular outflow tract toward the pulmonary artery; this curve is tight, more or less at a right angle in infants, leading to kinking of the sheath, which increases fluoroscopic time. This is the first reported case of a very large PDA (8.7 mm), larger than the aorta (8.2 mm), successfully closed by an Amplatzer angled duct occluder in an infant weighing 5 kg.

Transcatheter Closure of a Chronic Iatrogenic Arteriovenous Fistula Between the Carotid Artery and the Brachiocephalic Vein with an Amplatzer Duct Occluder in Combination with a Carotid Stent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stasek, Josef, E-mail: stasek@fnhk.c; Lojik, Miroslav; Bis, Josef

2009-05-15

We report an original method of transcatheter closure of an arteriovenous fistula using the combination of an Amplatzer PDA occluder and a carotid stent. The fistula was between the left carotid artery and the brachiocephalic vein. The patient had significant left-to-right shunt and was highly symptomatic. Due to the large orifice and pseudoaneurysmatic enlargement of the fistula, we had to use a large Amplatzer PDA occluder and the protruding part of the PDA device disk had to be covered with a carotid stent. The fistula was completely closed. The patient stopped having symptoms and, 2 years after the procedure, themore » effect persists.« less

The membrane fusion enigma: SNAREs, Sec1/Munc18 proteins, and their accomplices--guilty as charged?

PubMed

Rizo, Josep; Südhof, Thomas C

2012-01-01

Neurotransmitter release is governed by proteins that have homo-logs in most types of intracellular membrane fusion, including the Sec1/Munc18 protein Munc18-1 and the SNARE proteins syntaxin-1, synaptobrevin/VAMP, and SNAP-25. The SNAREs initiate fusion by forming tight SNARE complexes that bring the vesicle and plasma membranes together. SNARE maintenance in a functional state depends on two chaperone systems (Hsc70/αCSP/SGT and synuclein); defects in these systems lead to neurodegeneration. Munc18-1 binds to an autoinhibitory closed conformation of syntaxin-1, gating formation of SNARE complexes, and also binds to SNARE complexes, which likely underlies the crucial function of Munc18-1 in membrane fusion by an as-yet unclear mechanism. Syntaxin-1 opening is mediated by Munc13s through their MUN domain, which is homologous to diverse tethering factors and may also have a general role in fusion. MUN domain activity is likely modulated in diverse presynaptic plasticity processes that depend on Ca(2+) and RIM proteins, among others.

Safety and efficacy of Cardi-O-fix occluder for percutaneous closure of a patent foramen ovale

PubMed Central

Zhao, Enfa; Liu, Wenjuan; Zhang, Yushun; Cheng, Gesheng; Du, Yajuan; He, Lu; Wang, Xingye; He, Xumei

2017-01-01

Abstract Background: Amplatzer occluder and Cardio-O-fix occluder are currently used in percutaneous closure of patent foramen ovale. However, there is still a lack of relevant reports comparison the differences between them. The aim of this study was to evaluate the short-term and mid-term safety and efficacy of the Cardi-O-fix occluder in preventing recurrent cerebrovascular events in patients with a patent foramen ovale (PFO). Methods: We enrolled 246 patients (105 men) with a PFO from May 30, 2013 to March 30, 2015 in this single-center prospective study. All patients were treated by PFO interventional closure, with the Cardi-O-fix PFO occluder being used in 180 patients and the Amplatzer PFO occluder being utilized in the remaining 66 patients. After the procedure, we verified the safety and efficacy of different devices using contrast transthoracic echocardiography. Results: Neither recurrent stroke nor death was encountered during the follow-up of 12 months. Transient ischemic attack (TIA) was noted in 2 patients (1.1%) in the Cardi-O-fix PFO occluder group, and 1 patient suffered from TIA (1.5%) in the Amplatzer PFO occluder group. Among them, only 1 patient exhibited a small right to left shunt (RLS). There was no statistical difference in recurrent cerebral ischemic events. Three cases of paroxysmal atrial fibrillation were observed in the Cardi-O-fix PFO occluder group. One reverted spontaneously to sinus rhythm and the other 2 cases had pharmacologic conversion to sinus rhythm. One case of paroxysmal atrial fibrillation occurred in the Amplatzer group, which underwent pharmacologic conversion to sinus rhythm. There was no significant difference between the 2 groups regarding incidence of arrhythmia. No occluder translocation, erosion, pericardial effusion, and puncture site bleeding were observed in the 2 groups within 12 months of follow-up. The complete closure rates of the Cardi-O-fix and Amplatzer PFO occluder devices at the 12 months after the procedure were 73.9% and 63.6%, respectively, and the effective closure rates were 90.6% and 86.4%, respectively. There was no statistically significant difference in the complete closure rate and effective occlusion rate (P > 0.05) between the devices. Conclusions: There was no significant difference in the short- and mid-term efficacy and safety between the Cardi-O-fix PFO occluder and Amplatzer PFO occluder. The efficacy and safety of the Cardi-O-fix occluder were comparable to those of the Amplatzer PFO occluder. PMID:28383438

Membranes linked by trans-SNARE complexes require lipids prone to non-bilayer structure for progression to fusion.

PubMed

Zick, Michael; Stroupe, Christopher; Orr, Amy; Douville, Deborah; Wickner, William T

2014-01-01

Like other intracellular fusion events, the homotypic fusion of yeast vacuoles requires a Rab GTPase, a large Rab effector complex, SNARE proteins which can form a 4-helical bundle, and the SNARE disassembly chaperones Sec17p and Sec18p. In addition to these proteins, specific vacuole lipids are required for efficient fusion in vivo and with the purified organelle. Reconstitution of vacuole fusion with all purified components reveals that high SNARE levels can mask the requirement for a complex mixture of vacuole lipids. At lower, more physiological SNARE levels, neutral lipids with small headgroups that tend to form non-bilayer structures (phosphatidylethanolamine, diacylglycerol, and ergosterol) are essential. Membranes without these three lipids can dock and complete trans-SNARE pairing but cannot rearrange their lipids for fusion. DOI: http://dx.doi.org/10.7554/eLife.01879.001.

Arrest of trans-SNARE zippering uncovers loosely and tightly docked intermediates in membrane fusion.

PubMed

Yavuz, Halenur; Kattan, Iman; Hernandez, Javier Matias; Hofnagel, Oliver; Witkowska, Agata; Raunser, Stefan; Walla, Peter Jomo; Jahn, Reinhard

2018-04-17

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins mediate intracellular membrane fusion in the secretory pathway. They contain conserved regions, termed SNARE motifs, that assemble between opposing membranes directionally from their N-termini to their membrane-proximal C-termini in a highly exergonic reaction. However, how this energy is utilized to overcome the energy barriers along the fusion pathway is still under debate. Here we have used mutants of the SNARE synaptobrevin to arrest trans-SNARE zippering at defined stages. We have uncovered two distinct vesicle docking intermediates, where the membranes are loosely and tightly connected, respectively. The tightly connected state is irreversible and independent of maintaining assembled SNARE complexes. Together, our results shed new light on the intermediate stages along the pathway of membrane fusion. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Comparison of long-term clinical outcome between transcatheter Amplatzer occlusion and surgical closure of isolated patent ductus arteriosus.

PubMed

Chen, Zhao-yang; Wu, Li-ming; Luo, Yu-kun; Lin, Chao-gui; Peng, Ya-fei; Zhen, Xing-chun; Chen, Liang-long

2009-05-20

Transcatheter Amplatzer occlusion of patent ductus artertiosus (PDA) has emerged as a minimally invasive alternative to surgical closure. The goal of this study was to compare long-term clinical outcomes between two procedures, especially on chronic residual shunt, late or very late procedure-related complications, and regression of pulmonary hypertension and left ventricular dilation. A total 255 patients having isolated PDA with a minimal diameter of >or= 4 mm treated from January 2000 to July 2003 were included in this study and have been followed up until July 2008. The patients were assigned to either the device or surgical closure group according to the patients' and/or their parents' preference. Baseline physical exams, chest roentgenography, electrocardiography, and echocardiography were performed preprocedure and at each follow-up. Seventy-two patients accepted the transcatheter procedure (Group-TC) and 183 underwent surgical operation (Group-SO) for PDA closure, both groups were similar in their demographics and preoperative clinical characteristics. There were no cardiac deaths and late complications such as infectious endocarditis and Amplatzer duct occluder (ADO) dislodge in either group. More acute procedure-related complications were recorded in Group-SO (13.7%) compared with Group-TC (1.4%) (P = 0.004). The recovery time was (8.7 +/- 2.3) days for the Group-SO and (1.3 +/- 0.5) days for the Group-TC (P < 0.001). The survival freedom from persistent residual shunt, defined as residual shunt that can not resolve automatically, was 91.3% for Group-SO and 98.6% for Group-TC (P = 0.037 by Log-rank test). There was no significant difference in regression of pulmonary hypertension and left ventricular dilation; neither survival freedom from pulmonary hypertension nor abnormal left ventricular end-diastolic volume index were significantly different between the surgical group and the Amplatzer group. Our study confirmed the long-term safety and efficacy of transcatheter Amplatzer occlusion. In comparison to the time-proven surgical closure, transcatheter Amplatzer occlusion was less invasive and associated with fewer complications and residual shunt, and as effective in the regression of pulmonary hypertension and left ventricular dilation.

Entropic forces drive self-organization and membrane fusion by SNARE proteins

PubMed Central

Stratton, Benjamin S.; Warner, Jason M.; Rothman, James E.; O’Shaughnessy, Ben

2017-01-01

SNARE proteins are the core of the cell’s fusion machinery and mediate virtually all known intracellular membrane fusion reactions on which exocytosis and trafficking depend. Fusion is catalyzed when vesicle-associated v-SNAREs form trans-SNARE complexes (“SNAREpins”) with target membrane-associated t-SNAREs, a zippering-like process releasing ∼65 kT per SNAREpin. Fusion requires several SNAREpins, but how they cooperate is unknown and reports of the number required vary widely. To capture the collective behavior on the long timescales of fusion, we developed a highly coarse-grained model that retains key biophysical SNARE properties such as the zippering energy landscape and the surface charge distribution. In simulations the ∼65-kT zippering energy was almost entirely dissipated, with fully assembled SNARE motifs but uncomplexed linker domains. The SNAREpins self-organized into a circular cluster at the fusion site, driven by entropic forces that originate in steric–electrostatic interactions among SNAREpins and membranes. Cooperative entropic forces expanded the cluster and pulled the membranes together at the center point with high force. We find that there is no critical number of SNAREs required for fusion, but instead the fusion rate increases rapidly with the number of SNAREpins due to increasing entropic forces. We hypothesize that this principle finds physiological use to boost fusion rates to meet the demanding timescales of neurotransmission, exploiting the large number of v-SNAREs available in synaptic vesicles. Once in an unfettered cluster, we estimate ≥15 SNAREpins are required for fusion within the ∼1-ms timescale of neurotransmitter release. PMID:28490503

Snare coupling of the pre-pectoral pacing lead delivery catheter to the femoral transseptal apparatus for endocardial cardiac resynchronization therapy : mid-term results.

PubMed

Patel, Mehul B; Worley, Seth J

2013-04-01

Limitations imposed by the coronary sinus venous anatomy triggered the transseptal approach for endocardial LV lead placement. The alignment of the interatrial septum (IAS) and its neighborhood anatomy does not favor transseptal puncture from the pre-pectoral area. Locating and advancing a pre-pectoral LV lead delivery catheter (PDC) through an opening created in the IAS via femoral transseptal puncture (FTP) is time consuming and technically difficult. We describe a method where the PDC is snare coupled to the femoral transseptal apparatus (FTA). When the FTA is advanced into the left atrium (LA) the coupled PDC follows. The catheter of a 25-mm loop snare kit is replaced with the PDC (SelectSite®). The snare loop is positioned in the right common iliac vein from the pre-pectoral access. The PDC is coupled to the FTA by advancing the transseptal apparatus through the open snare loop. After conventional FTP, the FTA is withdrawn back into the right atrium (RA) over an extra support wire positioned in the LA. The PDC with open snare loop is pulled over the FTA up to the RA. The PDC is advanced to close the snare loop on the extra support wire immediately distal to the tip of the dilator close to the puncture site. The PDC is deflected to align with the FTA. The snare coupled catheters are gently advanced across the IAS into the LA. The PDC is released from the FTA by advancing the snare and opening the loop; the snare is then removed from the PDC. The PDC is deflected and advanced into the left ventricle (LV). After positioning the 4.1 Fr lumen less LV lead, the PDC is sliced and removed. The PDC snare coupled to the FTA was advanced into the LA in all five patients, however, access was lost during catheter manipulation in the one right-sided case. Endocardial LV lead was successfully positioned in all five patients. Snare coupling the pre-pectoral SelectSite® catheter to the FTA is technically simple, reliable and a safe method for transseptal endocardial LV lead placement for left pre-pectoral implantation.

Munc13-4 reconstitutes calcium-dependent SNARE-mediated membrane fusion

PubMed Central

Boswell, Kristin L.; James, Declan J.; Esquibel, Joseph M.; Bruinsma, Stephen; Shirakawa, Ryutaro; Horiuchi, Hisanori

2012-01-01

Munc13-4 is a widely expressed member of the CAPS/Munc13 protein family proposed to function in priming secretory granules for exocytosis. Munc13-4 contains N- and C-terminal C2 domains (C2A and C2B) predicted to bind Ca2+, but Ca2+-dependent regulation of Munc13-4 activity has not been described. The C2 domains bracket a predicted SNARE-binding domain, but whether Munc13-4 interacts with SNARE proteins is unknown. We report that Munc13-4 bound Ca2+ and restored Ca2+-dependent granule exocytosis to permeable cells (platelets, mast, and neuroendocrine cells) dependent on putative Ca2+-binding residues in C2A and C2B. Munc13-4 exhibited Ca2+-stimulated SNARE interactions dependent on C2A and Ca2+-dependent membrane binding dependent on C2B. In an apparent coupling of membrane and SNARE binding, Munc13-4 stimulated SNARE-dependent liposome fusion dependent on putative Ca2+-binding residues in both C2A and C2B domains. Munc13-4 is the first priming factor shown to promote Ca2+-dependent SNARE complex formation and SNARE-mediated liposome fusion. These properties of Munc13-4 suggest its function as a Ca2+ sensor at rate-limiting priming steps in granule exocytosis. PMID:22508512

Munc13-4 reconstitutes calcium-dependent SNARE-mediated membrane fusion.

PubMed

Boswell, Kristin L; James, Declan J; Esquibel, Joseph M; Bruinsma, Stephen; Shirakawa, Ryutaro; Horiuchi, Hisanori; Martin, Thomas F J

2012-04-16

Munc13-4 is a widely expressed member of the CAPS/Munc13 protein family proposed to function in priming secretory granules for exocytosis. Munc13-4 contains N- and C-terminal C2 domains (C2A and C2B) predicted to bind Ca(2+), but Ca(2+)-dependent regulation of Munc13-4 activity has not been described. The C2 domains bracket a predicted SNARE-binding domain, but whether Munc13-4 interacts with SNARE proteins is unknown. We report that Munc13-4 bound Ca(2+) and restored Ca(2+)-dependent granule exocytosis to permeable cells (platelets, mast, and neuroendocrine cells) dependent on putative Ca(2+)-binding residues in C2A and C2B. Munc13-4 exhibited Ca(2+)-stimulated SNARE interactions dependent on C2A and Ca(2+)-dependent membrane binding dependent on C2B. In an apparent coupling of membrane and SNARE binding, Munc13-4 stimulated SNARE-dependent liposome fusion dependent on putative Ca(2+)-binding residues in both C2A and C2B domains. Munc13-4 is the first priming factor shown to promote Ca(2+)-dependent SNARE complex formation and SNARE-mediated liposome fusion. These properties of Munc13-4 suggest its function as a Ca(2+) sensor at rate-limiting priming steps in granule exocytosis.

[Transcatheter closure of atrial septal defects in 40 pediatric patients].

PubMed

Deng, Dong-an; Zhu, Xian-yang; Hou, Chuan-ju; Han, Xiu-min; Wang, Qi-guang; Jin, Yan; Quan, Wei; Liu, Yang; Wang, Shu-fan

2003-07-01

To evaluate the clinical efficiency of transcatheter closure of atrial septal defect (ASD) with AGA-Amplatzer occlusion device in pediatric patients. Forty patients with ASD, 16 males, 24 females, at a mean age of 10.2 years (ranged from 3 to 15 years of age) and with a mean weight of 35.8 kg (ranged from 11 to 87 kg) were studied. Six cases were complicated with pulmonary stenosis (PS), 1 was complicated with ventricular tachycardia (VT). Right heart catheterizations were done in 40 patients for measuring the pressures of right ventricle and pulmonary artery. The balloon diameter of ASD was measured using balloon catheter with guiding wire. The diameter of ASD was measured by TTE and/or TEE, ascertaining the location and size of ASD. Amplatzer occlusion device was sized to be equal to or 1 - 2 mm more than the diameter of balloon stretched. All patients had successful implantation of the Amplatzer device. The success rate was 100%. The diameter measured by TTE was 7 - 30 mm (mean 17.12 mm). The diameter measured by TEE was 7 - 32 mm (mean 18.44 mm). The diameter of balloon stretched of ASD was 8 - 34 mm. Of the 40 cases, 6 were complicated with PS and accepted percutaneous balloon valvuloplasty (PBPV). One case was complicated with VT and accepted radiofrequency catheter ablation (RFCA). Neither complication nor residual shunt was found in any of the patients. The patients were recovered and followed up for 3 or 4 days after deployment of the Amplatzer device. Clinical symptom, cardiac murmur, and findings in ECG, echocardiography and X-ray were improved markedly. AGA-Amplatzer occlusion device is safe and efficient in pediatric patients with ASD.

Closure of large patent ductus arteriosus using the Amplatzer Septal Occluder.

PubMed

García-Montes, José A; Camacho-Castro, Anahí; Sandoval-Jones, Juan P; Buendía-Hernández, Alfonso; Calderón-Colmenero, Juan; Patiño-Bahena, Emilia; Zabal, Carlos

2015-03-01

Percutaneous closure of patent ductus arteriosus has become the treatment of choice in many centres. In patients with large ducts and pulmonary hypertension, transcatheter closure has been achieved with success using the Amplatzer Duct Occluder or even the Amplatzer Muscular Ventricular Septal Defect Occluder. We present a series of 17 patients with large and hypertensive ductus arteriosus who were treated with an Amplatzer Septal Occluder. The group had 11 female patients (64.7%) and a mean age of 18.6±12.1 years. The haemodynamic and anatomical data are as follows: pulmonary artery systolic pressure 71.3±31.8 mmHg, pulmonary to systemic flow ratio 3.14±1.36, ductal diameter at the pulmonary end 12.5±3.8 mm, and at the aortic end 20.2±7.7 mm; 14 cases (82.3%) had type A ducts. In 11 patients, we began the procedure using a different device - six with duct occluder and five with ventricular septal occluder - and it was changed because of device embolisation in six (35.3%). All septal occluders were delivered successfully. Residual shunt was moderate in six patients (35.3%), mild in eight (47%), trivial in two (11.8%), and no shunt in one (5.9%). Pulmonary systolic pressure decreased to 48.9±10.8 mmHg after occlusion (p=0.0015). Follow-up in 15 patients (88.2%) for 28.4±14.4 months showed complete closure in all cases but one, and continuous decrease of the pulmonary systolic pressure to 31.4±10.5 mmHg. No complications at follow-up have been reported. The Amplatzer Septal Occluder is a good alternative to percutaneously treat large and hypertensive ductus arteriosus.

Endovascular closure of ascending aortic pseudoaneurysm with a type II Amplatzer vascular plug.

PubMed

De Boo, Diederick W; Mott, Nigel; Kavnoudias, Helen; Walton, Antony; Lyon, Stuart M

2014-05-01

A 71-year-old man initially presented with an asymptomatic, incidentally detected ascending aortic pseudoaneurysm 25 years following aortic root repair with mechanical aortic valve replacement. This pseudoaneurysm was previously treated with coil embolization but due to coil impaction it reopened 8 years later. Endovascular closure of the pseudoaneurysm was achieved with the off-label use of a type II Amplatzer vascular plug.

Treatment of patent ductus arteriosus by the use of an Amplatz canine ductal occluder device

PubMed Central

White, Pam

2009-01-01

A 7-month-old female, spayed border collie was referred to the Ontario Veterinary College due to a continuous murmur noted by the referring veterinarian prior to ovariohysterectomy. Auscultation confirmed a grade VI/VI continuous murmur. An echocardiogram confirmed patent ductus arteriosus (PDA). An Amplatz canine ductal occluder device was successfully placed for occlusion of blood flow though the ductus. PMID:19436449

Catheter closure of patent foramen ovale in patients with cryptogenic cerebrovascular accidents: initial experiences in Japan.

PubMed

Kijima, Yasufumi; Akagi, Teiji; Nakagawa, Koji; Taniguchi, Manabu; Ueoka, Akira; Deguchi, Kentaro; Toh, Norihisa; Oe, Hiroki; Kusano, Kengo; Sano, Shunji; Ito, Hiroshi

2014-01-01

Although numerous studies have shown an association between a patent foramen ovale (PFO) and cryptogenic cerebrovascular accidents (CVA), there has been no definitive control study that demonstrated the benefit of percutaneous device closure of a PFO compared to medical therapy in patients with CVA. Additionally, few clinical data exist for Japanese patients in this field. We demonstrate the initial experiences in catheter closure of a PFO as secondary prevention of CVA in Japan. Catheter closure of a PFO was attempted in 7 patients who were diagnosed with cryptogenic CVA. Mean age at the procedure was 54 ± 19 years. The presence of spontaneous interatrial right-to-left shunts was demonstrated by transesophageal contrast echocardiography without Valsalva maneuver in all of the patients. Amplatzer Cribriform device (n = 4) or Amplatzer PFO Occluder (n = 3) was used for the procedure and was successfully deployed. Device-related complications were not observed at the time of the procedure or during the follow-up period (mean period of 16 ± 9 months). Catheter closure of a PFO could be safely performed with Amplatzer Cribriform or Amplatzer PFO Occluder. This procedure may contribute to prevention of recurrent cryptogenic CVA in Japanese patients.

Comparative analysis of plant genomes allows the definition of the "Phytolongins": a novel non-SNARE longin domain protein family

PubMed Central

2009-01-01

Background Subcellular trafficking is a hallmark of eukaryotic cells. Because of their pivotal role in the process, a great deal of attention has been paid to the SNARE proteins. Most R-SNAREs, or "longins", however, also possess a highly conserved, N-terminal fold. This "longin domain" is known to play multiple roles in regulating SNARE activity and targeting via interaction with other trafficking proteins. However, the diversity and complement of longins in eukaryotes is poorly understood. Results Our comparative genome survey identified a novel family of longin-related proteins, dubbed the "Phytolongins" because they are specific to land plants. Phytolongins share with longins the N-terminal longin domain and the C-terminal transmembrane domain; however, in the central region, the SNARE motif is replaced by a novel region. Phylogenetic analysis pinpoints the Phytolongins as a derivative of the plant specific VAMP72 longin sub-family and allows elucidation of Phytolongin evolution. Conclusion "Longins" have been defined as R-SNAREs composed of both a longin domain and a SNARE motif. However, expressed gene isoforms and splice variants of longins are examples of non-SNARE motif containing longins. The discovery of Phytolongins, a family of non-SNARE longin domain proteins, together with recent evidence on the conservation of the longin-like fold in proteins involved in both vesicle fusion (e.g. the Trs20 tether) and vesicle formation (e.g. σ and μ adaptin) highlight the importance of the longin-like domain in protein trafficking and suggest that it was one of the primordial building blocks of the eukaryotic membrane-trafficking machinery. PMID:19889231

A botulinum neurotoxin-like function of Potentilla chinensis extract that inhibits neuronal SNARE complex formation, membrane fusion, neuroexocytosis, and muscle contraction.

PubMed

Jung, Chang-Hwa; Choi, Jin-Kyu; Yang, Yoosoo; Koh, Hyun-Ju; Heo, Paul; Yoon, Kee-Jung; Kim, Sehyun; Park, Won-Seok; Shing, Hong-Ju; Kweon, Dae-Hyuk

2012-09-01

Botulinum neurotoxins (BoNTs) are popularly used to treat various diseases and for cosmetic purposes. They act by blocking neurotransmission through specific cleavage of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Recently, several polyphenols were shown to interfere with SNARE complex formation by wedging into the hydrophobic core interface, thereby leading to reduced neuroexocytosis. In order to find industrially-viable plant extract that functions like BoNT, 71 methanol extracts of flowers were screened and BoNT-like activity of selected extract was evaluated. After evaluating the inhibitory effect of 71 flower methanol extracts on SNARE complex formation, seven candidates were selected and they were subjected to SNARE-driven membrane fusion assay. Neurotransmitter release from neuronal PC12 cells and SNARE complex formation inside the cell was also evaluated. Finally, the effect of one selected extract on muscle contraction and digit abduction score was determined. The extract of Potentilla chinensis Ser. (Rosaceae)(Chinese cinquefoil) flower inhibited neurotransmitter release from neuronal PC12 cells by approximately 90% at a concentration of 10 μg/mL. The extract inhibited neuroexocytosis by interfering with SNARE complex formation inside cells. It reduced muscle contraction of phrenic nerve-hemidiaphragm by approximately 70% in 60 min, which is comparable to the action of the Ca²⁺-channel blocker verapamil and BoNT type A. While BoNT blocks neuroexocytosis by cleaving SNARE proteins, the Potentilla chinensis extract exhibited the same activity by inhibiting SNARE complex formation. The extract paralyzed muscle as efficiently as BoNT, suggesting the potential versatility in cosmetics and therapeutics.

Single-molecule studies of the neuronal SNARE fusion machinery.

PubMed

Brunger, Axel T; Weninger, Keith; Bowen, Mark; Chu, Steven

2009-01-01

SNAREs are essential components of the machinery for Ca(2+)-triggered fusion of synaptic vesicles with the plasma membrane, resulting in neurotransmitter release into the synaptic cleft. Although much is known about their biophysical and structural properties and their interactions with accessory proteins such as the Ca(2+) sensor synaptotagmin, their precise role in membrane fusion remains an enigma. Ensemble studies of liposomes with reconstituted SNAREs have demonstrated that SNAREs and accessory proteins can trigger lipid mixing/fusion, but the inability to study individual fusion events has precluded molecular insights into the fusion process. Thus, this field is ripe for studies with single-molecule methodology. In this review, we discuss applications of single-molecule approaches to observe reconstituted SNAREs, their complexes, associated proteins, and their effect on biological membranes. Some of the findings are provocative, such as the possibility of parallel and antiparallel SNARE complexes or of vesicle docking with only syntaxin and synaptobrevin, but have been confirmed by other experiments.

Application of a snare technique in retrograde chronic total occlusion percutaneous coronary intervention – a step by step practical approach and an observational study

PubMed Central

Fang, Hsiu-Yu; Lee, Wei-Chieh; Fang, Chih-Yuan; Wu, Chiung-Jen

2016-01-01

Abstract Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) has recently become popular among interventional cardiologists. CTO originating from the ostium has been one of the most difficult CTO lesions to treat with PCI for a number of reasons. Our aim was to illustrate a specific technique during retrograde CTO PCI referred to as the “snare technique.” We retrospectively examined the use of “snare technique” among 371 consecutive retrograde CTO PCIs performed at our institution between 2006 and 2015. “Snare technique” was used in 10 patients among the 371 retrograde CTO PCIs. The baseline clinical and angiographic characteristics of patients with or without “snare technique” were similar. The “snare technique” group had significantly fewer side branches at occlusion (30.0% vs 71.2%, P = 0.01) and a higher incidence of externalization (90% vs 25.5%, P < 0.001). The contrast volume was significantly lower in the “snare technique” group (285.0 ± 68.5 vs 379.2 ± 144.0, P = 0.04). The incidence of major complications, retrograde success, or final success did not differ between the groups. The “snare technique” is safe and feasible in retrograde CTO PCI, especially in cases of difficult coronary engagement in cases such as ostial occlusion, challenging coronary anatomy, or retrograde guidewire cannot get in antegrade guiding catheter. PMID:27741138

The Amplatzer Vascular Plug: Review of Evolution and Current Applications

PubMed Central

Lopera, Jorge E.

2015-01-01

The Amplatzer Vascular Plug (AVP) was created for peripheral embolization as a modification of the family of Amplatz septal occluders used in the treatment of congenital heart malformations. The device has evolved over the years and multiple versions have been launched into the market. Each of the versions of the device has some important modifications in terms of the size of the introducer's system, number of layers, and resultant thrombogenicity. It is very important for the operator to become familiar with the unique features of the AVP, and to understand the advantages and limitations of each model in the AVP family to achieve an optimal embolic result. The purpose of this article is to review the evolution and current clinical applications of the AVP in the field of interventional radiology, with emphasis on the advantages and limitations of this device in comparison with other embolization agents. PMID:26622098

A Stimulation Function of Synaptotagmin-1 in Ternary SNARE Complex Formation Dependent on Munc18 and Munc13

PubMed Central

Li, Yun; Wang, Shen; Li, Tianzhi; Zhu, Le; Xu, Yuanyuan; Ma, Cong

2017-01-01

The Ca2+ sensor synaptotagmin-1 (Syt1) plays an essential function in synaptic exocytosis. Recently, Syt1 has been implicated in synaptic vesicle priming, a maturation step prior to Ca2+-triggered membrane fusion that is believed to involve formation of the ternary SNARE complex and require priming proteins Munc18-1 and Munc13-1. However, the mechanisms of Syt1 in synaptic vesicle priming are still unclear. In this study, we found that Syt1 stimulates the transition from the Munc18-1/syntaxin-1 complex to the ternary SNARE complex catalyzed by Munc13-1. This stimulation can be further enhanced in a membrane-containing environment. Further, we showed that Syt1, together with Munc18-1 and Munc13-1, stimulates trans ternary SNARE complex formation on membranes in a manner resistant to disassembly factors NSF and α-SNAP. Disruption of a proposed Syt1/SNARE binding interface strongly abrogated the stimulation function of Syt1. Our results suggest that binding of Syt1 to an intermediate SNARE assembly with Munc18-1 and Munc13-1 is critical for the stimulation function of Syt1 in ternary SNARE complex formation, and this stimulation may underlie the priming function of Syt1 in synaptic exocytosis. PMID:28860966

Phosphatidic Acid Sequesters Sec18p from cis-SNARE Complexes to Inhibit Priming.

PubMed

Starr, Matthew L; Hurst, Logan R; Fratti, Rutilio A

2016-10-01

Yeast vacuole fusion requires the activation of cis-SNARE complexes through priming carried out by Sec18p/N-ethylmaleimide sensitive factor and Sec17p/α-SNAP. The association of Sec18p with vacuolar cis-SNAREs is regulated in part by phosphatidic acid (PA) phosphatase production of diacylglycerol (DAG). Inhibition of PA phosphatase activity blocks the transfer of membrane-associated Sec18p to SNAREs. Thus, we hypothesized that Sec18p associates with PA-rich membrane microdomains before transferring to cis-SNARE complexes upon PA phosphatase activity. Here, we examined the direct binding of Sec18p to liposomes containing PA or DAG. We found that Sec18p preferentially bound to liposomes containing PA compared with those containing DAG by approximately fivefold. Additionally, using a specific PA-binding domain blocked Sec18p binding to PA-liposomes and displaced endogenous Sec18p from isolated vacuoles. Moreover, the direct addition of excess PA blocked the priming activity of isolated vacuoles in a manner similar to chemically inhibiting PA phosphatase activity. These data suggest that the conversion of PA to DAG facilitates the recruitment of Sec18p to cis-SNAREs. Purified vacuoles from yeast lacking the PA phosphatase Pah1p showed reduced Sec18p association with cis-SNAREs and complementation with plasmid-encoded PAH1 or recombinant Pah1p restored the interaction. Taken together, this demonstrates that regulating PA concentrations by Pah1p activity controls SNARE priming by Sec18p. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Complexin induces a conformational change at the membrane-proximal C-terminal end of the SNARE complex

PubMed Central

Choi, Ucheor B; Zhao, Minglei; Zhang, Yunxiang; Lai, Ying; Brunger, Axel T

2016-01-01

Complexin regulates spontaneous and activates Ca2+-triggered neurotransmitter release, yet the molecular mechanisms are still unclear. Here we performed single molecule fluorescence resonance energy transfer experiments and uncovered two conformations of complexin-1 bound to the ternary SNARE complex. In the cis conformation, complexin-1 induces a conformational change at the membrane-proximal C-terminal end of the ternary SNARE complex that specifically depends on the N-terminal, accessory, and central domains of complexin-1. The complexin-1 induced conformation of the ternary SNARE complex may be related to a conformation that is juxtaposing the synaptic vesicle and plasma membranes. In the trans conformation, complexin-1 can simultaneously interact with a ternary SNARE complex via the central domain and a binary SNARE complex consisting of syntaxin-1A and SNAP-25A via the accessory domain. The cis conformation may be involved in activation of synchronous neurotransmitter release, whereas both conformations may be involved in regulating spontaneous release. DOI: http://dx.doi.org/10.7554/eLife.16886.001 PMID:27253060

Lipid Regulated Intramolecular Conformational Dynamics of SNARE-Protein Ykt6

NASA Astrophysics Data System (ADS)

Dai, Yawei; Seeger, Markus; Weng, Jingwei; Song, Song; Wang, Wenning; Tan, Yan-Wen

2016-08-01

Cellular informational and metabolic processes are propagated with specific membrane fusions governed by soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNARE). SNARE protein Ykt6 is highly expressed in brain neurons and plays a critical role in the membrane-trafficking process. Studies suggested that Ykt6 undergoes a conformational change at the interface between its longin domain and the SNARE core. In this work, we study the conformational state distributions and dynamics of rat Ykt6 by means of single-molecule Förster Resonance Energy Transfer (smFRET) and Fluorescence Cross-Correlation Spectroscopy (FCCS). We observed that intramolecular conformational dynamics between longin domain and SNARE core occurred at the timescale ~200 μs. Furthermore, this dynamics can be regulated and even eliminated by the presence of lipid dodecylphoshpocholine (DPC). Our molecular dynamic (MD) simulations have shown that, the SNARE core exhibits a flexible structure while the longin domain retains relatively stable in apo state. Combining single molecule experiments and theoretical MD simulations, we are the first to provide a quantitative dynamics of Ykt6 and explain the functional conformational change from a qualitative point of view.

Overexpression of the Qc-SNARE gene OsSYP71 enhances tolerance to oxidative stress and resistance to rice blast in rice (Oryza sativa L.).

PubMed

Bao, Yong-Mei; Sun, Shu-Jing; Li, Meng; Li, Li; Cao, Wen-Lei; Luo, Jia; Tang, Hai-Juan; Huang, Ji; Wang, Zhou-Fei; Wang, Jian-Fei; Zhang, Hong-Sheng

2012-08-10

OsSYP71 is an oxidative stress and rice blast response gene that encodes a Qc-SNARE protein in rice. Qc-SNARE proteins belong to the superfamily of SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), which function as important components of the vesicle trafficking machinery in eukaryotic cells. In this paper, 12 Qc-SNARE genes were isolated from rice, and expression patterns of 9 genes were detected in various tissues and in seedlings challenged with oxidative stresses and inoculated with rice blast. The expression of OsSYP71 was clearly up-regulated under these stresses. Overexpression of OsSYP71 in rice showed more tolerance to oxidative stress and resistance to rice blast than wild-type plants. These results indicate that Qc-SNAREs play an important role in rice response to environmental stresses, and OsSYP71 is useful in engineering crop plants with enhanced tolerance to oxidative stress and resistance to rice blast. Copyright © 2012 Elsevier B.V. All rights reserved.

Two synaptobrevin molecules are sufficient for vesicle fusion in central nervous system synapses

PubMed Central

Sinha, Raunak; Ahmed, Saheeb; Jahn, Reinhard; Klingauf, Jurgen

2011-01-01

Exocytosis of synaptic vesicles (SVs) during fast synaptic transmission is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly formed by the coil-coiling of three members of this protein family: vesicle SNARE protein, synaptobrevin 2 (syb2), and the presynaptic membrane SNAREs syntaxin-1A and SNAP-25. However, it is controversially debated how many SNARE complexes are minimally needed for SV priming and fusion. To quantify this effective number, we measured the fluorescence responses from single fusing vesicles expressing pHluorin (pHl), a pH-sensitive variant of GFP, fused to the luminal domain of the vesicular SNARE syb2 (spH) in cultured hippocampal neurons lacking endogenous syb2. Fluorescence responses were quantal, with the unitary signals precisely corresponding to single pHluorin molecules. Using this approach we found that two copies of spH per SV fully rescued evoked fusion whereas SVs expressing only one spH were unable to rapidly fuse upon stimulation. Thus, two syb2 molecules and likely two SNARE complexes are necessary and sufficient for SV fusion during fast synaptic transmission. PMID:21844343

CAPS drives trans-SNARE complex formation and membrane fusion through syntaxin interactions.

PubMed

James, Declan J; Kowalchyk, Judith; Daily, Neil; Petrie, Matt; Martin, Thomas F J

2009-10-13

Ca(2+)-dependent activator protein for secretion (CAPS) is an essential factor for regulated vesicle exocytosis that functions in priming reactions before Ca(2+)-triggered fusion of vesicles with the plasma membrane. However, the precise events that CAPS regulates to promote vesicle fusion are unclear. In the current work, we reconstituted CAPS function in a SNARE-dependent liposome fusion assay using VAMP2-containing donor and syntaxin-1/SNAP-25-containing acceptor liposomes. The CAPS stimulation of fusion required PI(4,5)P(2) in acceptor liposomes and was independent of Ca(2+), but Ca(2+) dependence was restored by inclusion of synaptotagmin. CAPS stimulated trans-SNARE complex formation concomitant with the stimulation of full membrane fusion at physiological SNARE densities. CAPS bound syntaxin-1, and CAPS truncations that competitively inhibited syntaxin-1 binding also inhibited CAPS-dependent fusion. The results revealed an unexpected activity of a priming protein to accelerate fusion by efficiently promoting trans-SNARE complex formation. CAPS may function in priming by organizing SNARE complexes on the plasma membrane.

Syntaxin1a variants lacking an N-peptide or bearing the LE mutation bind to Munc18a in a closed conformation

DOE PAGES

Colbert, Karen N.; Hattendorf, Douglas A.; Weiss, Thomas M.; ...

2013-07-15

In neurons, soluble N-ethylmaleimide–sensitive factor attachment receptor (SNARE) proteins drive the fusion of synaptic vesicles to the plasma membrane through the formation of a four-helix SNARE complex. Members of the Sec1/Munc18 protein family regulate membrane fusion through interactions with the syntaxin family of SNARE proteins. The neuronal protein Munc18a interacts with a closed conformation of the SNARE protein syntaxin1a (Syx1a) and with an assembled SNARE complex containing Syx1a in an open conformation. The N-peptide of Syx1a (amino acids 1–24) has been implicated in the transition of Munc18a-bound Syx1a to Munc18a-bound SNARE complex, but the underlying mechanism is not understood. Inmore » addition, we report the X-ray crystal structures of Munc18a bound to Syx1a with and without its native N-peptide (Syx1aΔN), along with small-angle X-ray scattering (SAXS) data for Munc18a bound to Syx1a, Syx1aΔN, and Syx1a L165A/E166A (LE), a mutation thought to render Syx1a in a constitutively open conformation. We show that all three complexes adopt the same global structure, in which Munc18a binds a closed conformation of Syx1a. We also identify a possible structural connection between the Syx1a N-peptide and SNARE domain that might be important for the transition of closed-to-open Syx1a in SNARE complex assembly. Although the role of the N-peptide in Munc18a-mediated SNARE complex assembly remains unclear, our results demonstrate that the N-peptide and LE mutation have no effect on the global conformation of the Munc18a–Syx1a complex.« less

Were snares and traps used in the Middle Stone Age and does it matter? A review and a case study from Sibudu, South Africa.

PubMed

Wadley, Lyn

2010-02-01

The concept of remote capture involved in the creation and use of snares and traps is one of several indicators that can be used for the recognition of enhanced working memory and complex cognition. It can be argued that this humble technology is a more reliable indicator of complex cognition than encounter hunting, for example with spears. It is difficult to recognize snares and traps archaeologically because they are generally made from materials that do not preserve well. To infer their presence in the past, it is therefore necessary to rely on circumstantial evidence such as mortality profiles, taxonomic diversity and high frequencies of creatures that are susceptible to capture in snares or traps. Clearly there are some problems with using snares to infer complex cognition because people do not necessarily choose meat-getting strategies with the lowest costs. Although snares make economic sense because they reduce search costs, their use by modern hunters is not associated with the type of status accorded to other means of hunting. Social demands, more than economic or environmental ones, may consequently have determined the amount of snaring and trapping that occurred in the past. Because of social attitudes, an absence of snaring need not mean that people were incapable of using this technique. At Sibudu, a South African Middle Stone Age site, snares or other non-selective capture techniques may have been used during the Howiesons Poort and perhaps also the Still Bay Industry. The circumstantial evidence consists of 1. high frequency representations of animals that prefer forested environments, including the tiny blue duiker (adult and juvenile) and the dangerous bushpig, 2. high frequencies of small mammals, 3. high taxonomic diversity and, 4. the presence of small carnivores. Importantly, the Howiesons Poort faunal assemblage is different from that in more recent Middle Stone Age occupations of the site.

Binding of SEC11 Indicates Its Role in SNARE Recycling after Vesicle Fusion and Identifies Two Pathways for Vesicular Traffic to the Plasma Membrane[OPEN

PubMed Central

Karnik, Rucha; Zhang, Ben; Waghmare, Sakharam; Aderhold, Christin; Grefen, Christopher; Blatt, Michael R.

2015-01-01

SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins drive vesicle fusion in all eukaryotes and contribute to homeostasis, pathogen defense, cell expansion, and growth in plants. Two homologous SNAREs, SYP121 (=SYR1/PEN1) and SYP122, dominate secretory traffic to the Arabidopsis thaliana plasma membrane. Although these proteins overlap functionally, differences between SYP121 and SYP122 have surfaced, suggesting that they mark two discrete pathways for vesicular traffic. The SNAREs share primary cognate partners, which has made separating their respective control mechanisms difficult. Here, we show that the regulatory protein SEC11 (=KEULE) binds selectively with SYP121 to affect secretory traffic mediated by this SNARE. SEC11 rescued traffic block by dominant-negative (inhibitory) fragments of both SNAREs, but only in plants expressing the native SYP121. Traffic and its rescue were sensitive to mutations affecting SEC11 interaction with the N terminus of SYP121. Furthermore, the domain of SEC11 that bound the SYP121 N terminus was itself able to block secretory traffic in the wild type and syp122 but not in syp121 mutant Arabidopsis. Thus, SEC11 binds and selectively regulates secretory traffic mediated by SYP121 and is important for recycling of the SNARE and its cognate partners. PMID:25747882

Gooseneck barnacles (Lepas spp.) ingest microplastic debris in the North Pacific Subtropical Gyre.

PubMed

Goldstein, Miriam C; Goodwin, Deborah S

2013-01-01

Substantial quantities of small plastic particles, termed "microplastic," have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG) since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the "rafting assemblage," are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp.), which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem.

Gooseneck barnacles (Lepas spp.) ingest microplastic debris in the North Pacific Subtropical Gyre

PubMed Central

Goodwin, Deborah S.

2013-01-01

Substantial quantities of small plastic particles, termed “microplastic,” have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG) since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the “rafting assemblage,” are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp.), which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem. PMID:24167779

Use of a rectal snare to remove a hypopharyngeal haemangioma.

PubMed

Abo-Khatwa, M M; Abouel-Enin, S; Klimach, O; Osborne, J

2007-02-01

We describe in this case report a new technique for treatment of hypopharyngeal haemangioma, using the surgical diathermy snare. The snare was easily introduced through the direct laryngoscope, without any difficulties. The procedure was simple, rapid and involved minimal bleeding. We also discuss the histological types of haemangioma, clinical picture, radiological findings and other modalities of treatment.

Involvement of SNARE complex in the hippocampus and prefrontal cortex of offspring with depression induced by prenatal stress.

PubMed

Cao, Yan Jun; Wang, Qiong; Zheng, Xing Xing; Cheng, Ying; Zhang, Yan

2018-08-01

Prenatal stress (PS) exposure can cause depression-like behavior in offspring, and maladaptive responses including physiological and neurobiological changes. Glutamate neurotransmission is implicated in effects of PS and in antidepressant mechanisms; however, the mechanisms underlying its involvement remain unclear. In the synapse, the formation of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex is essential for vesicular docking and neurotransmitter release. To explore effects of PS on the SNARE complex, pregnant rats were assigned to a control or PS group. Both male and female offspring in each group were used in this study. PS rats were exposed to restraint stress three times daily for 45 min on days 14-20 of pregnancy. In the PS offspring, the expression of the SNARE protein SNAP-25, vesicle-associated membrane protein (VAMP)-2, and Syntaxin 1a was significantly increased in the hippocampus and prefrontal cortex. These observations were associated with increased levels of proteins that chaperone SNARE complex formation, including Munc-18, α-synuclein, CSPα, complexin1, and complexin2. Immunoblotting of hippocampal and prefrontal cortex homogenates revealed significantly increased SNARE complex formation. vGluT1 protein expression was also significantly increased in the offspring. Additionally, PS was associated with increased mRNA expression of VAMP1, VAMP2, SNAP25, Syntaxin1a, and Syntaxin1b in the hippocampus and prefrontal cortex. Increased monomeric SNARE proteins, SNARE complex formation, vesicle-associated proteins, and vGluT1 may explain the increase in glutamate and its downstream excitotoxicity. These results support the hypothesis that glutamate release and vesicular glutamate transporters play a role in PS-induced depression-like behavior of rat offspring. Copyright © 2018. Published by Elsevier B.V.

Endovascular rescue method for undesirably stretched coil.

PubMed

Cho, Jae Hoon

2014-10-01

Undesirable detachment or stretching of coils within the parent artery during aneurysm embolization can be related with thrombus formation, which can be caused occlusion of parent artery or embolic event(s). To escape from this situation, several rescue methods have been reported. A case with undesirably stretched coil in which another rescue method was used, is presented. When the stretched coil is still located in the coil delivery microcatheter, the stretched coil can be removed safely using a snare and a handmade monorail microcatheter. After a snare is lodged in the handmade monorail microcatheter, the snare is introduced over the coil delivery micorcatheter and located in the distal part of the stretched coil. After then, the handmade monorail microcatheter captures the stretched coil and the snare as one unit. This technique using a handmade monorail microcatheter and a snare can be a good rescue modality for the undesirably stretched coil, still remained within the coil delivery microcatheter.

Endovascular Rescue Method for Undesirably Stretched Coil

PubMed Central

2014-01-01

Undesirable detachment or stretching of coils within the parent artery during aneurysm embolization can be related with thrombus formation, which can be caused occlusion of parent artery or embolic event(s). To escape from this situation, several rescue methods have been reported. A case with undesirably stretched coil in which another rescue method was used, is presented. When the stretched coil is still located in the coil delivery microcatheter, the stretched coil can be removed safely using a snare and a handmade monorail microcatheter. After a snare is lodged in the handmade monorail microcatheter, the snare is introduced over the coil delivery micorcatheter and located in the distal part of the stretched coil. After then, the handmade monorail microcatheter captures the stretched coil and the snare as one unit. This technique using a handmade monorail microcatheter and a snare can be a good rescue modality for the undesirably stretched coil, still remained within the coil delivery microcatheter. PMID:25371791

[Electrocautery snare efficacy in head and neck lesion treatment].

PubMed

Saito, Koichiro; Inagaki, Koji; Naganishi, Hideki; Takaoka, Takuji; Isogai, Yutaka; Ogawa, Kaoru

2009-11-01

The electrocautery snare has been widely used in gastroenterology and to remove bronchial and urinary bladder lesions, but rarely in head and lesion electrocautery. Since October 2006, we have used this instrument to treat 17 head and neck granuloma, papilloma, cyst, and cancer lesions under local or general anesthesia. Lesions were localized in the larynx, oropharynx, hypopharynx, or tracheostoma. The snare was used through a rhinolaryngovideoscope in most cases with a current of 15-30 watts produced by an electrosurgical generator. All procedures were easy, quick and successful, with minimal bleeding. No severe adverse effects were seen in any of our cases. The electrocautery snare was extremely useful in treating pedunculated lesions and in removing epiglottic cysts with a clear margin after excision of the mass without bleeding. Our results indicate the electrocautery snare to be useful and safe in treating selected head and neck lesion cases.

Large α-synuclein oligomers inhibit neuronal SNARE-mediated vesicle docking

PubMed Central

Choi, Bong-Kyu; Choi, Mal-Gi; Kim, Jae-Yeol; Yang, Yoosoo; Lai, Ying; Kweon, Dae-Hyuk; Lee, Nam Ki; Shin, Yeon-Kyun

2013-01-01

Parkinson disease and dementia with Lewy bodies are featured with the formation of Lewy bodies composed mostly of α-synuclein (α-Syn) in the brain. Although evidence indicates that the large oligomeric or protofibril forms of α-Syn are neurotoxic agents, the detailed mechanisms of the toxic functions of the oligomers remain unclear. Here, we show that large α-Syn oligomers efficiently inhibit neuronal SNARE-mediated vesicle lipid mixing. Large α-Syn oligomers preferentially bind to the N-terminal domain of a vesicular SNARE protein, synaptobrevin-2, which blocks SNARE-mediated lipid mixing by preventing SNARE complex formation. In sharp contrast, the α-Syn monomer has a negligible effect on lipid mixing even with a 30-fold excess compared with the case of large α-Syn oligomers. Thus, the results suggest that large α-Syn oligomers function as inhibitors of dopamine release, which thus provides a clue, at the molecular level, to their neurotoxicity. PMID:23431141

Amplatzer vascular plug as an embolic agent in different vascular pathologies: A pictorial essay

PubMed Central

Tresley, Jonathan; Bhatia, Shivank; Kably, Issam; Poozhikunnath Mohan, Prasoon; Salsamendi, Jason; Narayanan, Govindarajan

2016-01-01

The Amplatzer Vascular Plug (AVP) is a cylindrical plug made of self-expanding nitinol wire mesh with precise delivery control, which can be used for a variety of vascular pathologies. An AVP is an ideal vascular occlusion device particularly in high-flow vessels, where there is high risk of migration and systemic embolization with traditional occlusion devices. We performed 28 embolizations using the AVP from 2009 to 2014 and achieved complete occlusion without complications. PMID:27413276

Renal Artery Stump to Inferior Vena Cava Fistula: Unusual Clinical Presentation and Transcatheter Embolization with the Amplatzer Vascular Plug

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taneja, Manish; Lath, Narayan, E-mail: lath_narayan@yahoo.com; Soo, Tan Bien

Fistulous communication between the renal artery stump and inferior vena cava following nephrectomy is rare. We describe the case of a 52-year-old man with a fistula detected on investigation for hemolytic anemia in the postoperative period. The patient had had a nephrectomy performed 2 weeks prior to presentation for blunt abdominal trauma. The fistula was successfully occluded percutaneously using an Amplatzer vascular plug. The patient recovered completely and was discharged 2 weeks later.

SNAREs support atlastin-mediated homotypic ER fusion in Saccharomyces cerevisiae

PubMed Central

Lee, Miriam; Ko, Young-Joon; Moon, Yeojin; Han, Minsoo; Kim, Hyung-Wook; Lee, Sung Haeng; Kang, KyeongJin

2015-01-01

Dynamin-like GTPases of the atlastin family are thought to mediate homotypic endoplasmic reticulum (ER) membrane fusion; however, the underlying mechanism remains largely unclear. Here, we developed a simple and quantitative in vitro assay using isolated yeast microsomes for measuring yeast atlastin Sey1p-dependent ER fusion. Using this assay, we found that the ER SNAREs Sec22p and Sec20p were required for Sey1p-mediated ER fusion. Consistently, ER fusion was significantly reduced by inhibition of Sec18p and Sec17p, which regulate SNARE-mediated membrane fusion. The involvement of SNAREs in Sey1p-dependent ER fusion was further supported by the physical interaction of Sey1p with Sec22p and Ufe1p, another ER SNARE. Furthermore, our estimation of the concentration of Sey1p on isolated microsomes, together with the lack of fusion between Sey1p proteoliposomes even with a 25-fold excess of the physiological concentration of Sey1p, suggests that Sey1p requires additional factors to support ER fusion in vivo. Collectively, our data strongly suggest that SNARE-mediated membrane fusion is involved in atlastin-initiated homotypic ER fusion. PMID:26216899

8-Nitro-cGMP Attenuates the Interaction between SNARE Complex and Complexin through S-Guanylation of SNAP-25.

PubMed

Kishimoto, Yusuke; Kunieda, Kohei; Kitamura, Atsushi; Kakihana, Yuki; Akaike, Takaaki; Ihara, Hideshi

2018-02-21

8-Nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) is the second messenger in nitric oxide/reactive oxygen species redox signaling. This molecule covalently binds to protein thiol groups, called S-guanylation, and exerts various biological functions. Recently, we have identified synaptosomal-associated protein 25 (SNAP-25) as a target of S-guanylation, and demonstrated that S-guanylation of SNAP25 enhanced SNARE complex formation. In this study, we have examined the effects of S-guanylation of SNAP-25 on the interaction between the SNARE complex and complexin (cplx), which binds to the SNARE complex with a high affinity. Pull-down assays and coimmunoprecipitation experiments have revealed that S-guanylation of Cys90 in SNAP-25 attenuates the interaction between the SNARE complex and cplx. In addition, blue native-PAGE followed by Western blot analysis revealed that the amount of cplx detected at a high molecular weight decreased upon 8-nitro-cGMP treatment in SH-SY5Y cells. These results demonstrated for the first time that S-guanylation of SNAP-25 attenuates the interaction between the SNARE complex and cplx.

Lipid Regulated Intramolecular Conformational Dynamics of SNARE-Protein Ykt6

PubMed Central

Dai, Yawei; Seeger, Markus; Weng, Jingwei; Song, Song; Wang, Wenning; Tan, Yan-Wen

2016-01-01

Cellular informational and metabolic processes are propagated with specific membrane fusions governed by soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNARE). SNARE protein Ykt6 is highly expressed in brain neurons and plays a critical role in the membrane-trafficking process. Studies suggested that Ykt6 undergoes a conformational change at the interface between its longin domain and the SNARE core. In this work, we study the conformational state distributions and dynamics of rat Ykt6 by means of single-molecule Förster Resonance Energy Transfer (smFRET) and Fluorescence Cross-Correlation Spectroscopy (FCCS). We observed that intramolecular conformational dynamics between longin domain and SNARE core occurred at the timescale ~200 μs. Furthermore, this dynamics can be regulated and even eliminated by the presence of lipid dodecylphoshpocholine (DPC). Our molecular dynamic (MD) simulations have shown that, the SNARE core exhibits a flexible structure while the longin domain retains relatively stable in apo state. Combining single molecule experiments and theoretical MD simulations, we are the first to provide a quantitative dynamics of Ykt6 and explain the functional conformational change from a qualitative point of view. PMID:27493064

Analysis of the synaptotagmin family during reconstituted membrane fusion. Uncovering a class of inhibitory isoforms.

PubMed

Bhalla, Akhil; Chicka, Michael C; Chapman, Edwin R

2008-08-01

Ca(2+)-triggered exocytosis in neurons and neuroendocrine cells is regulated by the Ca(2+)-binding protein synaptotagmin (syt) I. Sixteen additional isoforms of syt have been identified, but little is known concerning their biochemical or functional properties. Here, we assessed the abilities of fourteen syt isoforms to directly regulate SNARE (soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor)-catalyzed membrane fusion. One group of isoforms stimulated neuronal SNARE-mediated fusion in response to Ca(2+), while another set inhibited SNARE catalyzed fusion in both the absence and presence of Ca(2+). Biochemical analysis revealed a strong correlation between the ability of syt isoforms to bind 1,2-dioleoyl phosphatidylserine (PS) and t-SNAREs in a Ca(2+)-promoted manner with their abilities to enhance fusion, further establishing PS and SNAREs as critical effectors for syt action. The ability of syt I to efficiently stimulate fusion was specific for certain SNARE pairs, suggesting that syts might contribute to the specificity of intracellular membrane fusion reactions. Finally, a subset of inhibitory syts down-regulated the ability of syt I to activate fusion, demonstrating that syt isoforms can modulate the function of each other.

Overexpression of a SNARE protein AtBS14b alters BR response in Arabidopsis.

PubMed

Zhu, Zhong Xin; Ye, Hong Bo; Xuan, Yuan Hu; Yao, Da Nian

2014-12-01

N-ethyl-maleimide sensitive factor adaptor protein receptor (SNAREs) domain-containing proteins were known as key players in vesicle-associated membrane fusion. Genetic screening has revealed the function of SNAREs in different aspects of plant biology, but the role of many SNAREs are still unknown. In this study, we have characterized the role of Arabidopsis Qc-SNARE protein AtBS14b in brassinosteroids (BRs) signaling pathway. AtBS14b overexpression (AtBS14b ox) plants exhibited short hypocotyl and petioles lengths as well as insensitivity to exogenously supplied BR, while AtBS14b mutants did not show any visible BR-dependent morphological differences. BR biosynthesis enzyme BR6OX2 expression was slightly lower in AtBS14b ox than in wild type plants. Further BR-mediated repression of BR6OX2, CPD and DWF4 was inhibited in AtBS14b ox plants. AtBS14b-mCherry fusion protein localized in vesicular compartments surrounding plasma membrane in N. benthamiana leaves. In addition, isolation of AtBS14b-interacting BR signaling protein, which localized in plasma membrane, showed that AtBS14b directly interacted with membrane steroid binding protein 1 (MSBP1), but did not interact with BAK1 or BRI1. These data suggested that Qc-SNARE protein AtBS14b is the first SNARE protein identified that interacts with MSBP1, and the overexpression of AtBS14b modulates BR response in Arabidopsis.

Evaluation of nutria (Myocastor coypus) detection methods in Maryland, USA

USGS Publications Warehouse

Pepper, Margaret A.; Herrmann, Valentine; Hines, James; Nichols, James D.; Kendrot, Stephen R

2017-01-01

Nutria (Myocaster coypus), invasive, semi-aquatic rodents native to South America, were introduced into Maryland near Blackwater National Wildlife Refuge (BNWR) in 1943. Irruptive population growth, expansion, and destructive feeding habits resulted in the destruction of thousands of acres of emergent marshes at and surrounding BNWR. In 2002, a partnership of federal, state and private entities initiated an eradication campaign to protect remaining wetlands from further damage and facilitate the restoration of coastal wetlands throughout the Chesapeake Bay region. Program staff removed nearly 14,000 nutria from five infested watersheds in a systematic trapping and hunting program between 2002 and 2014. As part of ongoing surveillance activities, the Chesapeake Bay Nutria Eradication Project uses a variety of tools to detect and remove nutria. Project staff developed a floating raft, or monitoring platform, to determine site occupancy. These platforms are placed along waterways and checked periodically for evidence of nutria visitation. We evaluated the effectiveness of monitoring platforms and three associated detection methods: hair snares, presence of scat, and trail cameras. Our objectives were to (1) determine if platform placement on land or water influenced nutria visitation rates, (2) determine if the presence of hair snares influenced visitation rates, and (3) determine method-specific detection probabilities. Our analyses indicated that platforms placed on land were 1.5–3.0 times more likely to be visited than those placed in water and that platforms without snares were an estimated 1.7–3.7 times more likely to be visited than those with snares. Although the presence of snares appears to have discouraged visitation, seasonal variation may confound interpretation of these results. Scat was the least effective method of determining nutria visitation, while hair snares were as effective as cameras. Estimated detection probabilities provided by occupancy modeling were 0.73 for hair snares, 0.71 for cameras and 0.40 for scat. We recommend the use of hair snares on monitoring platforms as they are the most cost-effective and reliable detection method available at this time. Future research should focus on determining the cause for the observed decrease in nutria visits after snares were applied.

Günther Tulip inferior vena cava filter retrieval using a bidirectional loop-snare technique.

PubMed

Ross, Jordan; Allison, Stephen; Vaidya, Sandeep; Monroe, Eric

2016-01-01

Many advanced techniques have been reported in the literature for difficult Günther Tulip filter removal. This report describes a bidirectional loop-snare technique in the setting of a fibrin scar formation around the filter leg anchors. The bidirectional loop-snare technique allows for maximal axial tension and alignment for stripping fibrin scar from the filter legs, a commonly encountered complication of prolonged dwell times.

SNARE-mediated trafficking of {alpha}{sub 5}{beta}{sub 1} integrin is required for spreading in CHO cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skalski, Michael; Coppolino, Marc G.

2005-10-07

In this study, the role of SNARE-mediated membrane traffic in regulating integrin localization was examined and the requirement for SNARE function in cellular spreading was quantitatively assessed. Membrane traffic was inhibited with the VAMP-specific catalytic light chain from tetanus toxin (TeTx-LC), a dominant-negative form (E329Q) of N-ethylmaleimide-sensitive fusion protein (NSF), and brefeldin A (BfA). Inhibition of membrane traffic with either E329Q-NSF or TeTx-LC, but not BfA, significantly inhibited spreading of CHO cells on fibronectin. Spreading was rescued in TeTx-LC-expressing cells by co-transfection with a TeTx-resistant cellubrevin/VAMP3. E329Q-NSF, a general inhibitor of SNARE function, was a more potent inhibitor of cellmore » spreading than TeTx-LC, suggesting that tetanus toxin-insensitive SNAREs contribute to adhesion. It was found that E329Q-NSF prevented trafficking of {alpha}{sub 5}{beta}{sub 1} integrins from a central Rab11-containing compartment to sites of protrusion during cell adhesion, while TeTx-LC delayed this trafficking. These results are consistent with a model of cellular adhesion that implicates SNARE function as an important component of integrin trafficking during the process of cell spreading.« less

ER-associated SNAREs and Sey1p mediate nuclear fusion at two distinct steps during yeast mating.

PubMed

Rogers, Jason V; Arlow, Tim; Inkellis, Elizabeth R; Koo, Timothy S; Rose, Mark D

2013-12-01

During yeast mating, two haploid nuclei fuse membranes to form a single diploid nucleus. However, the known proteins required for nuclear fusion are unlikely to function as direct fusogens (i.e., they are unlikely to directly catalyze lipid bilayer fusion) based on their predicted structure and localization. Therefore we screened known fusogens from vesicle trafficking (soluble N-ethylmaleimide-sensitive factor attachment protein receptors [SNAREs]) and homotypic endoplasmic reticulum (ER) fusion (Sey1p) for additional roles in nuclear fusion. Here we demonstrate that the ER-localized SNAREs Sec20p, Ufe1p, Use1p, and Bos1p are required for efficient nuclear fusion. In contrast, Sey1p is required indirectly for nuclear fusion; sey1Δ zygotes accumulate ER at the zone of cell fusion, causing a block in nuclear congression. However, double mutants of Sey1p and Sec20p, Ufe1p, or Use1p, but not Bos1p, display extreme ER morphology defects, worse than either single mutant, suggesting that retrograde SNAREs fuse ER in the absence of Sey1p. Together these data demonstrate that SNAREs mediate nuclear fusion, ER fusion after cell fusion is necessary to complete nuclear congression, and there exists a SNARE-mediated, Sey1p-independent ER fusion pathway.

Engineering botulinum neurotoxin domains for activation by toxin light chain.

PubMed

Stancombe, Patrick R; Masuyer, Geoffrey; Birch-Machin, Ian; Beard, Matthew; Foster, Keith A; Chaddock, John A; Acharya, K Ravi

2012-02-01

Targeted secretion inhibitors (TSI) are a new class of biopharmaceuticals designed from a botulinum neurotoxin protein scaffold. The backbone consists of the 50-kDa endopeptidase light chain and translocation domain (N-terminal portion of the heavy chain), lacks neuronal toxicity, but retains the ability to target cytoplasmic soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. TSI are produced as single-chain proteins and then cleaved post-translationally to generate functional heterodimers. Precise proteolytic cleavage is essential to activate the protein to a dichain form. TSI are themselves highly specific proteases. We have exploited this activity to create self-activating enzymes by replacing the native proteolytic site with a substrate SNARE peptide for the TSI protease. We have also created cross-activating backbones. By replacing the proteolytic activation site in one backbone with the substrate SNARE peptide for another serotype, controlled activation is achieved. SNARE peptides encompassing the whole of the coiled-coil region enabled complete activation and assembly of the dichain backbone. These engineered TSI backbones are capable of translocating their enzymatic domains to target intracellular SNARE proteins. They are also investigative tools with which to further the understanding of endopeptidase activity of light chain in SNARE interactions. © 2011 Syntaxin Ltd. Journal compilation © 2011 FEBS.

Endoscopic mucosal resection for middle and large colorectal polyps with a double-loop snare.

PubMed

Yoshida, Naohisa; Saito, Yutaka; Hirose, Ryohei; Ogiso, Kiyoshi; Inada, Yutaka; Yagi, Nobuaki; Naito, Yuji; Otake, Yosuke; Nakajima, Takeshi; Matsuda, Takahisa; Yanagisawa, Akio; Itoh, Yoshito

2014-01-01

This study aimed to analyze the endoscopic mucosal resection (EMR) with a novel uniquely shaped, double-loop snare (Dualoop, Medico's Hirata Inc., Tokyo, Japan) for colorectal polyps. This was a clinical trial conducted in two referral centers, Kyoto Prefectural University of Medicine and National Cancer Center Hospital in Japan. First, the firmness of various snares including 'Dualoop' was experimentally analyzed with a pressure gauge. Five hundred and eighty nine consecutive polyps that underwent EMR with 'Dualoop' were compared to 339 polyps with the standard round snare. Lesion characteristics, en bloc resection, and complications were analyzed. 'Dualoop' had the most firmness among the various snares. The average tumor size was 9.3 mm (5-30), and en bloc resection was achieved in 95.4%. The rate of en bloc resection for middle polyps 15-19 mm in diameter was significantly higher with the 'Dualoop' than that with the round snare (97.9 vs. 80.0%, p < 0.05). The rate of en bloc resection was 64.7% for large polyps ≥20 mm in diameter using 'Dualoop'. Higher age, larger tumor size, and superficial polyps were associated with the failure of en bloc resection. EMR with 'Dualoop' was effective for resecting both middle and large polyps en-bloc. © 2014 S. Karger AG, Basel.

WNK4 inhibits plasma membrane targeting of NCC through regulation of syntaxin13 SNARE formation.

PubMed

Chung, Woo Young; Park, Hyun Woo; Han, Jung Woo; Lee, Min Goo; Kim, Joo Young

2013-12-01

WNK4, a serine/threonine kinase, plays a critical role in the expression of membrane proteins in the cell surface; however, the underlying mechanism of WNK4 is not clear. Here, we demonstrate that WNK4 inhibits the fusion of plasma membrane delivering vesicle with sorting/recycling endosome through disrupting SNARE formation of syntaxin13, an endosomal t-SNARE and VAMP2, the v-SNARE in plasma membrane delivering vesicle. Their interaction and co-localization were enhanced by hyperosmotic stimulation which is known for WNK4 activation. The kinase domain of WNK4 interacts with the transmembrane domain (TM) of syntaxin13 and this interaction was abolished when the TM was replaced with that of syntaxin16. Interestingly, cell fractionation using sucrose gradients revealed that WNK4 inhibited the formation of the syntaxin13/VAMP2 SNARE complex in the endosomal compartment, but not syntaxin16/VAMP2 or syntaxin13/VAMP7. Syntaxin13 was not phosphorylated by WNK4 and WNK4KI also showed the same binding strength and similar inhibitory regulation on SNARE formation of syntaxin13. Physiological relevance of this mechanism was proved with the expression of NCC (Na(+) C1(-) co-transporter) in the cell surface. The inhibiting activity of WNK4 on surface expression of NCC was abolished by syntaxin13 siRNA transfection. These results suggest that WNK4 attenuates PM targeting of NCC proteins through regulation of syntaxin13 SNARE complex formation with VAMP2 in recycling and sorting endosome. © 2013.

Non-canonical role of the SNARE protein Ykt6 in autophagosome-lysosome fusion

PubMed Central

Takáts, Szabolcs; Glatz, Gábor; Szenci, Győző; Boda, Attila; Horváth, Gábor V.; Hegedűs, Krisztina; Kovács, Attila L.

2018-01-01

The autophagosomal SNARE Syntaxin17 (Syx17) forms a complex with Snap29 and Vamp7/8 to promote autophagosome-lysosome fusion via multiple interactions with the tethering complex HOPS. Here we demonstrate that, unexpectedly, one more SNARE (Ykt6) is also required for autophagosome clearance in Drosophila. We find that loss of Ykt6 leads to large-scale accumulation of autophagosomes that are unable to fuse with lysosomes to form autolysosomes. Of note, loss of Syx5, the partner of Ykt6 in ER-Golgi trafficking does not prevent autolysosome formation, pointing to a more direct role of Ykt6 in fusion. Indeed, Ykt6 localizes to lysosomes and autolysosomes, and forms a SNARE complex with Syx17 and Snap29. Interestingly, Ykt6 can be outcompeted from this SNARE complex by Vamp7, and we demonstrate that overexpression of Vamp7 rescues the fusion defect of ykt6 loss of function cells. Finally, a point mutant form with an RQ amino acid change in the zero ionic layer of Ykt6 protein that is thought to be important for fusion-competent SNARE complex assembly retains normal autophagic activity and restores full viability in mutant animals, unlike palmitoylation or farnesylation site mutant Ykt6 forms. As Ykt6 and Vamp7 are both required for autophagosome-lysosome fusion and are mutually exclusive subunits in a Syx17-Snap29 complex, these data suggest that Vamp7 is directly involved in membrane fusion and Ykt6 acts as a non-conventional, regulatory SNARE in this process. PMID:29694367

Calcium Regulates Molecular Interactions of Otoferlin with Soluble NSF Attachment Protein Receptor (SNARE) Proteins Required for Hair Cell Exocytosis*

PubMed Central

Ramakrishnan, Neeliyath A.; Drescher, Marian J.; Morley, Barbara J.; Kelley, Philip M.; Drescher, Dennis G.

2014-01-01

Mutations in otoferlin, a C2 domain-containing ferlin family protein, cause non-syndromic hearing loss in humans (DFNB9 deafness). Furthermore, transmitter secretion of cochlear inner hair cells is compromised in mice lacking otoferlin. In the present study, we show that the C2F domain of otoferlin directly binds calcium (KD = 267 μm) with diminished binding in a pachanga (D1767G) C2F mouse mutation. Calcium was found to differentially regulate binding of otoferlin C2 domains to target SNARE (t-SNARE) proteins and phospholipids. C2D–F domains interact with the syntaxin-1 t-SNARE motif with maximum binding within the range of 20–50 μm Ca2+. At 20 μm Ca2+, the dissociation rate was substantially lower, indicating increased binding (KD = ∼10−9) compared with 0 μm Ca2+ (KD = ∼10−8), suggesting a calcium-mediated stabilization of the C2 domain·t-SNARE complex. C2A and C2B interactions with t-SNAREs were insensitive to calcium. The C2F domain directly binds the t-SNARE SNAP-25 maximally at 100 μm and with reduction at 0 μm Ca2+, a pattern repeated for C2F domain interactions with phosphatidylinositol 4,5-bisphosphate. In contrast, C2F did not bind the vesicle SNARE protein synaptobrevin-1 (VAMP-1). Moreover, an antibody targeting otoferlin immunoprecipitated syntaxin-1 and SNAP-25 but not synaptobrevin-1. As opposed to an increase in binding with increased calcium, interactions between otoferlin C2F domain and intramolecular C2 domains occurred in the absence of calcium, consistent with intra-C2 domain interactions forming a “closed” tertiary structure at low calcium that “opens” as calcium increases. These results suggest a direct role for otoferlin in exocytosis and modulation of calcium-dependent membrane fusion. PMID:24478316

Green fluorescence protein-based content-mixing assay of SNARE-driven membrane fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heo, Paul; Kong, Byoungjae; Jung, Young-Hun

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins mediate intracellular membrane fusion by forming a ternary SNARE complex. A minimalist approach utilizing proteoliposomes with reconstituted SNARE proteins yielded a wealth of information pinpointing the molecular mechanism of SNARE-mediated fusion and its regulation by accessory proteins. Two important attributes of a membrane fusion are lipid-mixing and the formation of an aqueous passage between apposing membranes. These two attributes are typically observed by using various fluorescent dyes. Currently available in vitro assay systems for observing fusion pore opening have several weaknesses such as cargo-bleeding, incomplete removal of unencapsulated dyes, and inadequate information regardingmore » the size of the fusion pore, limiting measurements of the final stage of membrane fusion. In the present study, we used a biotinylated green fluorescence protein and streptavidin conjugated with Dylight 594 (DyStrp) as a Föster resonance energy transfer (FRET) donor and acceptor, respectively. This FRET pair encapsulated in each v-vesicle containing synaptobrevin and t-vesicle containing a binary acceptor complex of syntaxin 1a and synaptosomal-associated protein 25 revealed the opening of a large fusion pore of more than 5 nm, without the unwanted signals from unencapsulated dyes or leakage. This system enabled determination of the stoichiometry of the merging vesicles because the FRET efficiency of the FRET pair depended on the molar ratio between dyes. Here, we report a robust and informative assay for SNARE-mediated fusion pore opening. - Highlights: • SNARE proteins drive membrane fusion and open a pore for cargo release. • Biotinylated GFP and DyStrp was used as the reporter pair of fusion pore opening. • Procedure for efficient SNARE reconstitution and reporter encapsulation was established. • The FRET pair reported opening of a large fusion pore bigger than 5 nm. • The assay was robust and provided information of stoichiometry of vesicle fusion.« less

Transcatheter closure of a large patent ductus arteriosus in a young child using the Amplatzer duct occluder.

PubMed

Jan, S-L; Hwang, B; Fu, Y-C; Chi, C-S

2005-01-01

The Amplatzer duct occluder (ADO) provides a safe and effective therapy for patients with moderate- to large-sized patent ductus arteriosus (PDA), but there have been few reports of transcatheter closure of very large PDAs in young children and infants. We report a successful transcatheter closure of a very large PDA, 10.5 mm in diameter at the narrowest point, with a 14/12-mm ADO. To our knowledge, this is the largest PDA ever closed by an interventional method in such a young child.

Successful Occlusion of a Ruptured Aortic Aneurysm Using the Amplatzer Vascular Plug: A Technical Note

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zander, Tobias, E-mail: tobiaszander@gmx.de; Baldi, Sebastian; Rabellino, Martin

2011-02-15

Ruptured abdominal aortic aneurysm is related with a 100% mortality rate if left untreated. Even with surgical intervention or endovascular repair, mortality is still extremely high. However, there are conditions in which neither open surgical aneurysm repair nor endovascular aneurysm repair can be considered a viable therapeutic option because of comorbidities or anatomic reasons. We report a case of successful endovascular treatment in a patient with ruptured abdominal aortic aneurysm by occluding the abdominal aneurysm using the Amplatzer Vascular Plug (AVP II).

Use of an Amplatzer Device for Endoscopic Closure of a Large Bronchopleural Fistula following Lobectomy for a Stage I Squamous Cell Carcinoma.

PubMed

Ottevaere, A; Slabbynck, H; Vermeersch, P; Rogiers, P; Galdermans, D; De Droogh, E; Bedert, L

2013-01-01

Bronchopleural fistulas can occur as a rare but severe complication after pulmonary resection. Established guidelines for the proper treatment of patients with bronchopleural fistulas do not exist. Apart from attempts to close the fistula, emphasis is placed on preventive measures, early treatment with antibiotics, drainage of the empyema and aggressive nutritional and rehabilitative support. For inoperable patients, endoscopic procedures are the only therapeutic option. Unfortunately, large (>8 mm) or central bronchopleural fistulas are usually not suitable for such endoscopic management. Recently, some groups have published a few case reports about a novel technique for the endobronchial closure of bronchopleural fistulas, using an Amplatzer device, originally designed for transcatheter closure of cardiac septal defects. We applied the same technique as a life-saving treatment in a ventilated patient who was considered inoperable due to a high oxygen need. The operation was successful. The patient could be weaned from ventilation and was eventually discharged from the hospital to a rehabilitation facility several weeks after the insertion of the device. Until now, endoscopic techniques have only been useful for the treatment of small, peripheral, bronchopleural fistulas and even then only as a bridge to surgery in high-risk surgical patients. In this case report, we demonstrate that the use of an Amplatzer device can expand the importance of endoscopic techniques in the treatment of bronchopleural fistulas. An Amplatzer device, for endobronchial closure, can indeed be administered for large and central bronchopleural fistulas. Moreover, it can be considered as a definite alternative to surgery in inoperable patients.

[Lung perfusion studies after percutaneous closure of patent ductus arteriosus using the Amplatzer Duct Occluder in children].

PubMed

Parra-Bravo, José Rafael; Apolonio-Martínez, Adriana; Estrada-Loza, María de Jesús; Beirana-Palencia, Luisa Gracia; Ramírez-Portillo, César Iván

2015-01-01

The closure of patent ductus arteriosus with multiple devices has been associated with a reduction in lung perfusion. We evaluated the pulmonary perfusion after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder device using perfusion lung scan. Thirty patients underwent successful percutaneous patent ductus arteriosus occlusions using the Amplatzer Duct Occluder device were included in this study. Lung perfusion scans were preformed 6 months after the procedure. Peak flow velocities and protrusion of the device were analyzed by Doppler echocardiography. A left lung perfusion<40% was considered abnormal. The device implantation was successful in all patients. Average perfusion of left lung was 44.7±4.9% (37.8-61.4). Five patients (16.6%) showed decreased perfusion of the left lung. Age, low weight, the length of the ductus arteriosus and the minimum and maximum diameter/length of the ductus arteriosus ratio were statistically significant in patients with abnormalities of lung perfusion. It was observed protrusion the device in 6 patients with a higher maximum flow rate in the left pulmonary artery. The left lung perfusion may be compromised after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder. The increased flow velocity in the origin of the left pulmonary artery can be a poor indicator of reduction in pulmonary perfusion and can occur in the absence of protrusion of the device. Copyright © 2014 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

Functional diversification of Arabidopsis SEC1-related SM proteins in cytokinetic and secretory membrane fusion.

PubMed

Karnahl, Matthias; Park, Misoon; Krause, Cornelia; Hiller, Ulrike; Mayer, Ulrike; Stierhof, York-Dieter; Jürgens, Gerd

2018-06-12

Sec1/Munc18 (SM) proteins contribute to membrane fusion by interacting with Qa-SNAREs or nascent trans -SNARE complexes. Gymnosperms and the basal angiosperm Amborella have only a single SEC1 gene related to the KEULE gene in Arabidopsis However, the genomes of most angiosperms including Arabidopsis encode three SEC1-related SM proteins of which only KEULE has been functionally characterized as interacting with the cytokinesis-specific Qa-SNARE KNOLLE during cell-plate formation. Here we analyze the closest paralog of KEULE named SEC1B. In contrast to the cytokinesis defects of keule mutants, sec1b mutants are homozygous viable. However, the keule sec1b double mutant was nearly gametophytically lethal, displaying collapsed pollen grains, which suggests substantial overlap between SEC1B and KEULE functions in secretion-dependent growth. SEC1B had a strong preference for interaction with the evolutionarily ancient Qa-SNARE SYP132 involved in secretion and cytokinesis, whereas KEULE interacted with both KNOLLE and SYP132. This differential interaction with Qa-SNAREs is likely conferred by domains 1 and 2a of the two SM proteins. Comparative analysis of all four possible combinations of the relevant SEC1 Qa-SNARE double mutants revealed that in cytokinesis, the interaction of SEC1B with KNOLLE plays no role, whereas the interaction of KEULE with KNOLLE is prevalent and functionally as important as the interactions of both SEC1B and KEU with SYP132 together. Our results suggest that functional diversification of the two SEC1-related SM proteins during angiosperm evolution resulted in enhanced interaction of SEC1B with Qa-SNARE SYP132, and thus a predominant role of SEC1B in secretion.

Functional interaction of the SNARE protein NtSyp121 in Ca2+ channel gating, Ca2+ transients and ABA signalling of stomatal guard cells.

PubMed

Sokolovski, Sergei; Hills, Adrian; Gay, Robert A; Blatt, Michael R

2008-03-01

There is now growing evidence that membrane vesicle trafficking proteins, especially of the superfamily of SNAREs, are critical for cellular signalling in plants. Work from this laboratory first demonstrated that a soluble, inhibitory (dominant-negative) fragment of the SNARE NtSyp121 blocked K+ and Cl- channel responses to the stress-related hormone abscisic acid (ABA), but left open a question about functional impacts on signal intermediates, especially on Ca2+-mediated signalling events. Here, we report one mode of action for the SNARE mediated directly through alterations in Ca2+ channel gating and its consequent effects on cytosolic-free [Ca2+] ([Ca2+]i) elevation. We find that expressing the same inhibitory fragment of NtSyp121 blocks ABA-evoked stomatal closure, but only partially suppresses stomatal closure in the presence of the NO donor, SNAP, which promotes [Ca2+]i elevation independently of the plasma membrane Ca2+ channels. Consistent with these observations, Ca2+ channel gating at the plasma membrane is altered by the SNARE fragment in a manner effective in reducing the potential for triggering a rise in [Ca2+]i, and we show directly that its expression in vivo leads to a pronounced suppression of evoked [Ca2+]i transients. These observations offer primary evidence for the functional coupling of the SNARE with Ca2+ channels at the plant cell plasma membrane and, because [Ca2+]i plays a key role in the control of K+ and Cl- channel currents in guard cells, they underscore an important mechanism for SNARE integration with ion channel regulation during stomatal closure.

The Arabidopsis R-SNARE VAMP721 Interacts with KAT1 and KC1 K+ Channels to Moderate K+ Current at the Plasma Membrane.

PubMed

Zhang, Ben; Karnik, Rucha; Wang, Yizhou; Wallmeroth, Niklas; Blatt, Michael R; Grefen, Christopher

2015-06-01

SNARE (soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) proteins drive vesicle traffic, delivering membrane and cargo to target sites within the cell and at its surface. They contribute to cell homeostasis, morphogenesis, and pathogen defense. A subset of SNAREs, including the Arabidopsis thaliana SNARE SYP121, are known also to coordinate solute uptake via physical interactions with K(+) channels and to moderate their gating at the plasma membrane. Here, we identify a second subset of SNAREs that interact to control these K(+) channels, but with opposing actions on gating. We show that VAMPs (vesicle-associated membrane proteins), which target vesicles to the plasma membrane, also interact with and suppress the activities of the inward-rectifying K(+) channels KAT1 and KC1. Interactions were evident in yeast split-ubiquitin assays, they were recovered in vivo by ratiometric bimolecular fluorescence complementation, and they were sensitive to mutation of a single residue, Tyr-57, within the longin domain of VAMP721. Interaction was also recovered on exchange of the residue at this site in the homolog VAMP723, which normally localizes to the endoplasmic reticulum and otherwise did not interact. Functional analysis showed reduced channel activity and alterations in voltage sensitivity that are best explained by a physical interaction with the channel gates. These actions complement those of SYP121, a cognate SNARE partner of VAMP721, and lead us to propose that the channel interactions reflect a "hand-off" in channel control between the two SNARE proteins that is woven together with vesicle fusion. © 2015 American Society of Plant Biologists. All rights reserved.

Small peptides patterned after the N-terminus domain of SNAP25 inhibit SNARE complex assembly and regulated exocytosis.

PubMed

Blanes-Mira, Clara; Merino, Jaime M; Valera, Elvira; Fernández-Ballester, Gregorio; Gutiérrez, Luis M; Viniegra, Salvador; Pérez-Payá, Enrique; Ferrer-Montiel, Antonio

2004-01-01

Synthetic peptides patterned after the C-terminus of synaptosomal associated protein of 25 kDa (SNAP25) efficiently abrogate regulated exocytosis. In contrast, the use of SNAP25 N-terminal-derived peptides to modulate SNAP receptors (SNARE) complex assembly and neurosecretion has not been explored. Here, we show that the N-terminus of SNAP25, specially the segment that encompasses 22Ala-44Ile, is essential for the formation of the SNARE complex. Peptides patterned after this protein domain are potent inhibitors of SNARE complex formation. The inhibitory activity correlated with their propensity to adopt an alpha-helical secondary structure. These peptides abrogated SNARE complex formation only when added previous to the onset of aggregate assembly. Analysis of the mechanism of action revealed that these peptides disrupted the binary complex formed by SNAP25 and syntaxin. The identified peptides inhibited Ca2+-dependent exocytosis from detergent-permeabilized excitable cells. Noteworthy, these amino acid sequences markedly protected intact hippocampal neurones against hypoglycaemia-induced, glutamate-mediated excitotoxicity with a potency that rivalled that displayed by botulinum neurotoxins. Our findings indicate that peptides patterned after the N-terminus of SNAP25 are potent inhibitors of SNARE complex formation and neuronal exocytosis. Because of their activity in intact neurones, these cell permeable peptides may be hits for antispasmodic and analgesic drug development.

ER-associated SNAREs and Sey1p mediate nuclear fusion at two distinct steps during yeast mating

PubMed Central

Rogers, Jason V.; Arlow, Tim; Inkellis, Elizabeth R.; Koo, Timothy S.; Rose, Mark D.

2013-01-01

During yeast mating, two haploid nuclei fuse membranes to form a single diploid nucleus. However, the known proteins required for nuclear fusion are unlikely to function as direct fusogens (i.e., they are unlikely to directly catalyze lipid bilayer fusion) based on their predicted structure and localization. Therefore we screened known fusogens from vesicle trafficking (soluble N-ethylmaleimide–sensitive factor attachment protein receptors [SNAREs]) and homotypic endoplasmic reticulum (ER) fusion (Sey1p) for additional roles in nuclear fusion. Here we demonstrate that the ER-localized SNAREs Sec20p, Ufe1p, Use1p, and Bos1p are required for efficient nuclear fusion. In contrast, Sey1p is required indirectly for nuclear fusion; sey1Δ zygotes accumulate ER at the zone of cell fusion, causing a block in nuclear congression. However, double mutants of Sey1p and Sec20p, Ufe1p, or Use1p, but not Bos1p, display extreme ER morphology defects, worse than either single mutant, suggesting that retrograde SNAREs fuse ER in the absence of Sey1p. Together these data demonstrate that SNAREs mediate nuclear fusion, ER fusion after cell fusion is necessary to complete nuclear congression, and there exists a SNARE-mediated, Sey1p-independent ER fusion pathway. PMID:24152736

A tethering complex drives the terminal stage of SNARE-dependent membrane fusion

NASA Astrophysics Data System (ADS)

D'Agostino, Massimo; Risselada, Herre Jelger; Lürick, Anna; Ungermann, Christian; Mayer, Andreas

2017-11-01

Membrane fusion in eukaryotic cells mediates the biogenesis of organelles, vesicular traffic between them, and exo- and endocytosis of important signalling molecules, such as hormones and neurotransmitters. Distinct tasks in intracellular membrane fusion have been assigned to conserved protein systems. Tethering proteins mediate the initial recognition and attachment of membranes, whereas SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein complexes are considered as the core fusion engine. SNARE complexes provide mechanical energy to distort membranes and drive them through a hemifusion intermediate towards the formation of a fusion pore. This last step is highly energy-demanding. Here we combine the in vivo and in vitro fusion of yeast vacuoles with molecular simulations to show that tethering proteins are critical for overcoming the final energy barrier to fusion pore formation. SNAREs alone drive vacuoles only into the hemifused state. Tethering proteins greatly increase the volume of SNARE complexes and deform the site of hemifusion, which lowers the energy barrier for pore opening and provides the driving force. Thereby, tethering proteins assume a crucial mechanical role in the terminal stage of membrane fusion that is likely to be conserved at multiple steps of vesicular traffic. We therefore propose that SNAREs and tethering proteins should be considered as a single, non-dissociable device that drives fusion. The core fusion machinery may then be larger and more complex than previously thought.

Soluble N-Ethylmaleimide-Sensitive Factor Attachment Protein Receptor-Derived Peptides for Regulation of Mast Cell Degranulation.

PubMed

Yang, Yoosoo; Kong, Byoungjae; Jung, Younghoon; Park, Joon-Bum; Oh, Jung-Mi; Hwang, Jaesung; Cho, Jae Youl; Kweon, Dae-Hyuk

2018-01-01

Vesicle-associated V-soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and target membrane-associated T-SNAREs (syntaxin 4 and SNAP-23) assemble into a core trans -SNARE complex that mediates membrane fusion during mast cell degranulation. This complex plays pivotal roles at various stages of exocytosis from the initial priming step to fusion pore opening and expansion, finally resulting in the release of the vesicle contents. In this study, peptides with the sequences of various SNARE motifs were investigated for their potential inhibitory effects against SNARE complex formation and mast cell degranulation. The peptides with the sequences of the N-terminal regions of vesicle-associated membrane protein 2 (VAMP2) and VAMP8 were found to reduce mast cell degranulation by inhibiting SNARE complex formation. The fusion of protein transduction domains to the N-terminal of each peptide enabled the internalization of the fusion peptides into the cells equally as efficiently as cell permeabilization by streptolysin-O without any loss of their inhibitory activities. Distinct subsets of mast cell granules could be selectively regulated by the N-terminal-mimicking peptides derived from VAMP2 and VAMP8, and they effectively decreased the symptoms of atopic dermatitis in mouse models. These results suggest that the cell membrane fusion machinery may represent a therapeutic target for atopic dermatitis.

Transcatheter Amplatzer vascular plug-embolization of a giant postnephrectomy arteriovenous fistula combined with an aneurysm of the renal pedicle by through-and-through, arteriovenous access

PubMed Central

Kayser, Ole; Schäfer, Philipp

2013-01-01

Although endovascular transcatheter embolization of arteriovenous fistulas is minimally invasive, the torrential flow prevailing within a fistula implies the risk of migration of the deployed embolization devices into the downstream venous and pulmonary circulation. We present the endovascular treatment of a giant postnephrectomy arteriovenous fistula between the right renal pedicle and the residual renal vein in a 63-year-old man. The purpose of this case report is to demonstrate that the Amplatzer vascular plug (AVP) can be safely positioned to embolize even relatively large arteriovenous fistulas (AVFs). Secondly, we illustrate that this occluder can even be introduced to the fistula via a transvenous catheter in cases where it is initially not possible to advance the deployment-catheter through a tortuous feeder artery. Migration of the vascular plug was ruled out at follow-up 4 months subsequently to the intervention. Thus, the Amplatzer vascular plug and the arteriovenous through-and-through guide wire access with subsequent transvenous deployment should be considered in similar cases. PMID:23326248

Snapin mediates insulin secretory granule docking, but not trans-SNARE complex formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Somanath, Sangeeta; Partridge, Christopher J.; Marshall, Catriona

Secretory granule exocytosis is a tightly regulated process requiring granule targeting, tethering, priming, and membrane fusion. At the heart of this process is the SNARE complex, which drives fusion through a coiled-coil zippering effect mediated by the granule v-SNARE protein, VAMP2, and the plasma membrane t-SNAREs, SNAP-25 and syntaxin-1A. Here we demonstrate that in pancreatic β-cells the SNAP-25 accessory protein, snapin, C-terminal H2 domain binds SNAP-25 through its N-terminal Sn-1 domain. Interestingly whilst snapin binds SNAP-25, there is only modest binding of this complex with syntaxin-1A under resting conditions. Instead synataxin-1A appears to be recruited in response to secretory stimulation.more » These results indicate that snapin plays a role in tethering insulin granules to the plasma membrane through coiled coil interaction of snapin with SNAP-25, with full granule fusion competency only resulting after subsequent syntaxin-1A recruitment triggered by secretory stimulation. - Highlights: • Snapin mediates granule docking. • Snapin binds SNAP-25. • SNARE complex forms downstream.« less

Hybrid treatment of dysphagia lusoria: right carotid to subclavian bypass and endovascular insertion of an Amplatzer II Vascular Plug.

PubMed

Cobos-González, Ernesto; Aragón-López, Jose Arturo; García Buen-Abad, Ricardo; Rojas, José A; Gutiérrez, Abraham

2016-12-01

Compression of the esophagus by a retroesophageal aberrant right subclavian artery (ARSA) is a rare cause of dysphagia. We present the case of a 47-year-old female with symptoms of progressive dysphagia diagnosed with dysphagia lusoria using barium swallow and contrast computed tomography and successfully treated with a hybrid procedure: right carotid to subclavian bypass and endovascular insertion of an Amplatzer II Vascular Plug through the right superficial femoral artery. We consider this approach safer, less invasive and more complete to avoid recurrent dysphagia.

Successful transcatheter closure of a large patent ductus venosus with the Amplatzer vascular plug II.

PubMed

Cho, Y K; Chang, N-K; Ma, J S

2009-05-01

Patent ductus venosus is a rare form of congenital portosystemic shunt from the fetal umbilical vein to the inferior vena cava. The reported surgical treatments include ligation, banding, and liver transplantation. In addition, transcatheter closure with a coil, stent, or original Amplatzer vascular plug (AVP) has been reported. The AVP II, a redesigned version of the original vascular plug with a finer more densely woven nitinol wire and a large diameter (up to 22 mm) is available. This reported case is the first successful occlusion of a large patent ductus venosus with the new AVP II.

In Vitro Reconstitution of Autophagosome-Lysosome Fusion.

PubMed

Diao, J; Li, L; Lai, Y; Zhong, Q

2017-01-01

SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) proteins are a highly regulated class of membrane proteins lying in the center of membrane fusion. In conjunction with accessory proteins, SNAREs drive efficient merger of two distinct lipid bilayers into one interconnected structure. This chapter describes our fluorescence resonance energy transfer (FRET)-based proteoliposome fusion assays for the roles of various SNARE proteins, accessory proteins, and effects of different lipid compositions on membrane fusion involved in autophagy. © 2017 Elsevier Inc. All rights reserved.

Channel Compensation for Speaker Recognition using MAP Adapted PLDA and Denoising DNNs

DTIC Science & Technology

2016-06-21

improvement has been the availability of large quantities of speaker-labeled data from telephone recordings. For new data applications, such as audio from...mi- crophone channels to the telephone channel. Audio files were rejected if the alignment process failed. At the end of the pro- cess a total of 873...Microphone 01 AT3035 ( Audio Technica Studio Mic) 02 MX418S (Shure Gooseneck Mic) 03 Crown PZM Soundgrabber II 04 AT Pro45 ( Audio Technica Hanging Mic

LegC3, an Effector Protein from Legionella pneumophila, Inhibits Homotypic Yeast Vacuole Fusion In Vivo and In Vitro

PubMed Central

Bennett, Terry L.; Kraft, Shannon M.; Reaves, Barbara J.; Mima, Joji; O’Brien, Kevin M.; Starai, Vincent J.

2013-01-01

During infection, the intracellular pathogenic bacterium Legionella pneumophila causes an extensive remodeling of host membrane trafficking pathways, both in the construction of a replication-competent vacuole comprised of ER-derived vesicles and plasma membrane components, and in the inhibition of normal phagosome:endosome/lysosome fusion pathways. Here, we identify the LegC3 secreted effector protein from L. pneumophila as able to inhibit a SNARE- and Rab GTPase-dependent membrane fusion pathway in vitro, the homotypic fusion of yeast vacuoles (lysosomes). This vacuole fusion inhibition appeared to be specific, as similar secreted coiled-coiled domain containing proteins from L. pneumophila, LegC7/YlfA and LegC2/YlfB, did not inhibit vacuole fusion. The LegC3-mediated fusion inhibition was reversible by a yeast cytosolic extract, as well as by a purified soluble SNARE, Vam7p. LegC3 blocked the formation of trans-SNARE complexes during vacuole fusion, although we did not detect a direct interaction of LegC3 with the vacuolar SNARE protein complexes required for fusion. Additionally, LegC3 was incapable of inhibiting a defined synthetic model of vacuolar SNARE-driven membrane fusion, further suggesting that LegC3 does not directly inhibit the activity of vacuolar SNAREs, HOPS complex, or Sec17p/18p during membrane fusion. LegC3 is likely utilized by Legionella to modulate eukaryotic membrane fusion events during pathogenesis. PMID:23437241

A symbiosis-dedicated SYNTAXIN OF PLANTS 13II isoform controls the formation of a stable host-microbe interface in symbiosis.

PubMed

Huisman, Rik; Hontelez, Jan; Mysore, Kirankumar S; Wen, Jiangqi; Bisseling, Ton; Limpens, Erik

2016-09-01

Arbuscular mycorrhizal (AM) fungi and rhizobium bacteria are accommodated in specialized membrane compartments that form a host-microbe interface. To better understand how these interfaces are made, we studied the regulation of exocytosis during interface formation. We used a phylogenetic approach to identify target soluble N-ethylmaleimide-sensitive factor-attachment protein receptors (t-SNAREs) that are dedicated to symbiosis and used cell-specific expression analysis together with protein localization to identify t-SNAREs that are present on the host-microbe interface in Medicago truncatula. We investigated the role of these t-SNAREs during the formation of a host-microbe interface. We showed that multiple syntaxins are present on the peri-arbuscular membrane. From these, we identified SYNTAXIN OF PLANTS 13II (SYP13II) as a t-SNARE that is essential for the formation of a stable symbiotic interface in both AM and rhizobium symbiosis. In most dicot plants, the SYP13II transcript is alternatively spliced, resulting in two isoforms, SYP13IIα and SYP13IIβ. These splice-forms differentially mark functional and degrading arbuscule branches. Our results show that vesicle traffic to the symbiotic interface is specialized and required for its maintenance. Alternative splicing of SYP13II allows plants to replace a t-SNARE involved in traffic to the plasma membrane with a t-SNARE that is more stringent in its localization to functional arbuscules. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Evolutionarily diverse SYP1 Qa-SNAREs jointly sustain pollen tube growth in Arabidopsis.

PubMed

Slane, Daniel; Reichardt, Ilka; El Kasmi, Farid; Bayer, Martin; Jürgens, Gerd

2017-11-01

Intracellular membrane fusion is effected by SNARE proteins that reside on adjacent membranes and form bridging trans-SNARE complexes. Qa-SNARE members of the Arabidopsis SYP1 family are involved in membrane fusion at the plasma membrane or during cell plate formation. Three SYP1 family members have been classified as pollen-specific as inferred from gene expression profiling studies, and two of them, SYP124 and SYP125, are confined to angiosperms. The SYP124 gene appears genetically unstable, whereas its sister gene SYP125 shows essentially no variation among Arabidopsis accessions. The third pollen-specific member SYP131 is sister to SYP132, which appears evolutionarily conserved in the plant lineage. Although evolutionarily diverse, the three SYP1 proteins are functionally overlapping in that only the triple mutant syp124 syp125 syp131 shows a specific and severe male gametophytic defect. While pollen development and germination appear normal, pollen tube growth is arrested during passage through the style. Our results suggest that angiosperm pollen tubes employ a combination of ancient and modern Qa-SNARE proteins to sustain their growth-promoting membrane dynamics during the reproductive process. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

Reconstitution of SNARE proteins into solid-supported lipid bilayer stacks and X-ray structure analysis.

PubMed

Xu, Yihui; Kuhlmann, Jan; Brennich, Martha; Komorowski, Karlo; Jahn, Reinhard; Steinem, Claudia; Salditt, Tim

2018-02-01

SNAREs are known as an important family of proteins mediating vesicle fusion. For various biophysical studies, they have been reconstituted into supported single bilayers via proteoliposome adsorption and rupture. In this study we extended this method to the reconstitution of SNAREs into supported multilamellar lipid membranes, i.e. oriented multibilayer stacks, as an ideal model system for X-ray structure analysis (X-ray reflectivity and diffraction). The reconstitution was implemented through a pathway of proteomicelle, proteoliposome and multibilayer. To monitor the structural evolution in each step, we used small-angle X-ray scattering for the proteomicelles and proteoliposomes, followed by X-ray reflectivity and grazing-incidence small-angle scattering for the multibilayers. Results show that SNAREs can be successfully reconstituted into supported multibilayers, with high enough orientational alignment for the application of surface sensitive X-ray characterizations. Based on this protocol, we then investigated the effect of SNAREs on the structure and phase diagram of the lipid membranes. Beyond this application, this reconstitution protocol could also be useful for X-ray analysis of many further membrane proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

Snaring to control feral pigs sus scrofa in a remote Hawaiian rain forest

USGS Publications Warehouse

Anderson, Stephen J.; Stone, Charles P.

1993-01-01

Feral pig Sus scrofa control in Kipahulu Valley, a remote rain forest in Haleakala National Park, Maui, Hawaiian Islands, has been achieved with snares over a 45-month period. Initial pig densities in fenced management units of 6·2 km2 and 7·8 km2were estimated at 6 animals/km2 and 14·3 animals/km2 for the two units, based on population reconstruction from animals killed and aged. During the 45 months of the study, 1978 snares were set, and 1·6 million snare nights were logged. Snare density reached 96/km2 and 200/km2 for the two management units by the end of the study. A mean effort of 43 worker hours/pig was used to remove 53 pigs from the upper management unit, and a mean of 7 worker hours/pig to remove 175 animals from the more densely populated lower unit. Pig activity monitoring along transects provided a good measure of control effectiveness until densities of about 1 pig/km2 were achieved, after which transects became less useful than scouting for determining pig activity.

Gradual Hunterian ligation for infected prosthetic bypass.

PubMed

Egun, A; Slade, D; McCollum, C N

2000-04-01

To review gradual snare occlusion for the management of complex or recurrent graft infection. Medical records of patients treated with gradual snare occlusion following graft infection were reviewed for indication for operation, type of bypass and graft material used. In addition, infecting organism, grade of infection (Szilágyi) and outcome were recorded. Four femoropopliteal, two extra-anatomic (axillofemoral) and aortobifemoral bypasses were included in this study. All had chronic infection (Szilágyi grade III) with onset of 4 to 24 months and two of which were recurrent. The causative organisms were coagulase-negative staphylococci, Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus in three patients, with no organism isolated in the remaining cases. There was no loss of limb following gradual snare occlusion but there was only one death due to aortic stump rupture 2 weeks later. Gradual snare occlusion is an alternative for the management of chronic or recurrent graft infection. Copyright 1999 Harcourt Publishers Ltd.

Exertional myopathy in a grizzly bear (Ursus arctos) captured by leghold snare.

PubMed

Cattet, Marc; Stenhouse, Gordon; Bollinger, Trent

2008-10-01

We diagnosed exertional myopathy (EM) in a grizzly bear (Ursus arctos) that died approximately 10 days after capture by leghold snare in west-central Alberta, Canada, in June 2003. The diagnosis was based on history, post-capture movement data, gross necropsy, histopathology, and serum enzyme levels. We were unable to determine whether EM was the primary cause of death because autolysis precluded accurate evaluation of all tissues. Nevertheless, comparison of serum aspartate aminotransferase and creatine kinase concentrations and survival between the affected bear and other grizzly bears captured by leghold snare in the same research project suggests EM also occurred in other bears, but that it is not generally a cause of mortality. We propose, however, occurrence of nonfatal EM in grizzly bears after capture by leghold snare has potential implications for use of this capture method, including negative effects on wildlife welfare and research data.

Synaptotagmin-1 may be a distance regulator acting upstream of SNARE nucleation

PubMed Central

van den Bogaart, Geert; Thutupalli, Shashi; Risselada, Jelger H.; Meyenberg, Karsten; Holt, Matthew; Riedel, Dietmar; Diederichsen, Ulf; Herminghaus, Stephan; Grubmüller, Helmut; Jahn, Reinhard

2011-01-01

Synaptotagmin-1 triggers Ca2+-sensitive, rapid neurotransmitter release by promoting the interaction of SNARE proteins between the synaptic vesicles and the plasma membrane. How synaptotagmin-1 promotes this interaction is controversial, and the massive increase in membrane fusion efficiency of Ca2+-synaptotagmin-1 has not been reproduced in vitro. However, previous experiments have been performed at relatively high salt concentrations, screening potentially important electrostatic interactions. Using functional reconstitution in liposomes, we show here that at low ionic strength SNARE-mediated membrane fusion becomes strictly dependent on both Ca2+ and synaptotagmin-1. Under these conditions, synaptotagmin-1 functions as a distance regulator: tethering the liposomes too far for SNARE nucleation in the absence of Ca2+, but brings the liposomes close enough for membrane fusion in the presence of Ca2+. These results may explain how the relatively weak electrostatic interactions of synaptotagmin-1 with membranes substantially accelerate fusion. PMID:21642968

Surgical repair of tricuspid valve leaflet tear following percutaneous closure of perimembranous ventricular septal defect using Amplatzer duct occluder I: Report of two cases

PubMed Central

Kuwelker, Saatchi Mahesh; Shetty, Devi Prasad; Dalvi, Bharat

2017-01-01

Tricuspid valve (TV) injury following transcatheter closure of perimembranous ventricular septal defect (PMVSD) with Amplatzer ductal occluder I (ADO I), requiring surgical repair, is rare. We report two cases of TV tear involving the anterior and septal leaflets following PMVSD closure using ADO I. In both the patients, the subvalvular apparatus remained unaffected. The patients presented with severe tricuspid regurgitation (TR) 6 weeks and 3 months following the device closure. They underwent surgical repair with patch augmentation of the TV leaflets. Postoperatively, both are asymptomatic with a mild residual TR. PMID:28163430

The off-label use of the Amplatzer muscular VSD occluder for large patent ductus arteriosus: a case report and review.

PubMed

Cubeddu, Roberto J; Babin, Ivan; Inglessis, Ignacio

2014-07-01

A percutaneous approach to the closure of patent ductus arteriosus (PDA) is the preferred procedure in the majority of cases. However, there is little experience with percutaneous closure of unusually large PDA. We report the case of a 28-year-old female with moderate left ventricular dilation and pulmonary hypertension resulting from a large 16 mm PDA. Percutaneous closure was successfully performed using an off-label Amplatzer muscular ventricular septal defect occluder after intravascular ultrasound assessment. Technical challenges, including accurate assessment of defect size and device selection are exemplified along with a comprehensive overview of the available literature.

Myocilin, a Component of a Membrane-Associated Protein Complex Driven by a Homologous Q-SNARE Domain

PubMed Central

Dismuke, W. Michael; McKay, Brian S.; Stamer, W. Daniel

2012-01-01

Myocilin is a widely expressed protein with no known function, however, mutations in myocilin appear to manifest uniquely as ocular hypertension and the blinding disease glaucoma. Using the protein homology/analogy recognition engine (PHYRE) we find that the olfactomedin domain of myocilin is similar in sequence motif and structure to a six-bladed, kelch repeat motif based on the known crystal structures of such proteins. Additionally, using sequence analysis we identify a coiled-coil segment of myocilin with homology to human Q-SNARE proteins. Using COS-7 cells expressing full length human myocilin and a version lacking the C-terminal olfactomedin domain, we identified a membrane-associated protein complex containing myocilin by hydrodynamic analysis. The myocilin construct that included the coiled-coil but lacked the olfactomedin domain formed complexes similar to the full-length protein, indicating that the coiled-coil domain of myocilin is sufficient for myocilin to bind to the large detergent resistant complex. In human retina and retinal pigment epithelium, which express myocilin, we detected the protein in a large, SDS-resistant, membrane-associated complex. We characterized the hydrodynamic properties of myocilin in human tissues as either a 15s complex with an Mr=405,000–440,000 yielding a slightly elongated globular shape similar to known SNARE complexes or a dimer of 6.4s and Mr=108,000. By identifying the Q-SNARE homology within the second coil of myocilin and documenting its participation in a SNARE-like complex, we provide evidence of a SNARE domain containing protein associated with a human disease. PMID:22463803

MoVam7, a Conserved SNARE Involved in Vacuole Assembly, Is Required for Growth, Endocytosis, ROS Accumulation, and Pathogenesis of Magnaporthe oryzae

PubMed Central

Dou, Xianying; Wang, Qi; Qi, Zhongqiang; Song, Wenwen; Wang, Wei; Guo, Min; Zhang, Haifeng; Zhang, Zhengguang; Wang, Ping; Zheng, Xiaobo

2011-01-01

Soluble NSF attachment protein receptor (SNARE) proteins play a central role in membrane fusion and vesicle transport of eukaryotic organisms including fungi. We previously identified MoSce22 as a homolog of Saccharomyces cerevisiae SNARE protein Sec22 to be involved in growth, stress resistance, and pathogenicity of Magnaporthe oryzae. Here, we provide evidences that MoVam7, an ortholog of S. cerevisiae SNARE protein Vam7, exerts conserved functions in vacuolar morphogenesis and functions in pathogenicity of M. oryzae. Staining with neutral red and FM4-64 revealed the presence of abnormal fragmented vacuoles and an absence of the Spitzenkörper body in the ΔMovam7 mutant. The ΔMovam7 mutant also exhibited reduced vegetative growth, poor conidiation, and failure to produce the infection structure appressorium. Additionally, treatments with cell wall perturbing agents indicated weakened cell walls and altered distributions of the cell wall component chitin. Furthermore, the ΔMovam7 mutant showed a reduced accumulation of reactive oxygen species (ROS) in the hyphal apex and failed to cause diseases on the rice plant. In summary, our studies indicate that MoVam7, like MoSec22, is a component of the SNARE complex whose functions in vacuole assembly also underlies the growth, conidiation, appressorium formation, and pathogenicity of M. oryzae. Further studies of MoVam7, MoSec22, and additional members of the SNARE complex are likely to reveal critical mechanisms in vacuole formation and membrane trafficking that is linked to fungal pathogenicity. PMID:21283626

Towards reconstitution of membrane fusion mediated by SNAREs and other synaptic proteins

PubMed Central

Brunger, Axel T.; Cipriano, Daniel J.; Diao, Jiajie

2015-01-01

Abstract Proteoliposomes have been widely used for in vitro studies of membrane fusion mediated by synaptic proteins. Initially, such studies were made with large unsynchronized ensembles of vesicles. Such ensemble assays limited the insights into the SNARE-mediated fusion mechanism that could be obtained from them. Single particle microscopy experiments can alleviate many of these limitations but they pose significant technical challenges. Here we summarize various approaches that have enabled studies of fusion mediated by SNAREs and other synaptic proteins at a single-particle level. Currently available methods are described and their advantages and limitations are discussed. PMID:25788028

ATG14 controls SNARE-mediated autophagosome fusion with a lysosome.

PubMed

Liu, Rong; Zhi, Xiaoyong; Zhong, Qing

2015-01-01

Autophagosome fusion with a lysosome constitutes the last barrier for autophagic degradation. It is speculated that this fusion process is precisely and tightly regulated. Recent genetic evidence suggests that a set of SNARE proteins, including STX17, SNAP29, and VAMP8, are essential for the fusion between autophagosomes and lysosomes. However, it remains unclear whether these SNAREs are fusion competent and how their fusogenic activity is specifically regulated during autophagy. Using a combination of biochemical, cell biology, and genetic approaches, we demonstrated that fusogenic activity of the autophagic SNARE complex is temporally and spatially controlled by ATG14/Barkor/Atg14L, an essential autophagy-specific regulator of the class III phosphatidylinositol 3-kinase complex (PtdIns3K). ATG14 directly binds to the STX17-SNAP29 binary complex on autophagosomes and promotes STX17-SNAP29-VAMP8-mediated autophagosome fusion with lysosomes. ATG14 homo-oligomerization is required for SNARE binding and fusion promotion, but is dispensable for PtdIns3K stimulation and autophagosome biogenesis. Consequently, ATG14 homo-oligomerization is required for autophagosome fusion with a lysosome, but is dispensable for autophagosome biogenesis. These data support a key role of ATG14 in controlling autophagosome fusion with a lysosome.

Phosphatidylinositol 4,5-bisphosphate regulates SNARE-dependent membrane fusion.

PubMed

James, Declan J; Khodthong, Chuenchanok; Kowalchyk, Judith A; Martin, Thomas F J

2008-07-28

Phosphatidylinositol 4,5-bisphosphate (PI 4,5-P(2)) on the plasma membrane is essential for vesicle exocytosis but its role in membrane fusion has not been determined. Here, we quantify the concentration of PI 4,5-P(2) as approximately 6 mol% in the cytoplasmic leaflet of plasma membrane microdomains at sites of docked vesicles. At this concentration of PI 4,5-P(2) soluble NSF attachment protein receptor (SNARE)-dependent liposome fusion is inhibited. Inhibition by PI 4,5-P(2) likely results from its intrinsic positive curvature-promoting properties that inhibit formation of high negative curvature membrane fusion intermediates. Mutation of juxtamembrane basic residues in the plasma membrane SNARE syntaxin-1 increase inhibition by PI 4,5-P(2), suggesting that syntaxin sequesters PI 4,5-P(2) to alleviate inhibition. To define an essential rather than inhibitory role for PI 4,5-P(2), we test a PI 4,5-P(2)-binding priming factor required for vesicle exocytosis. Ca(2+)-dependent activator protein for secretion promotes increased rates of SNARE-dependent fusion that are PI 4,5-P(2) dependent. These results indicate that PI 4,5-P(2) regulates fusion both as a fusion restraint that syntaxin-1 alleviates and as an essential cofactor that recruits protein priming factors to facilitate SNARE-dependent fusion.

Septin dynamics are essential for exocytosis.

PubMed

Tokhtaeva, Elmira; Capri, Joe; Marcus, Elizabeth A; Whitelegge, Julian P; Khuzakhmetova, Venera; Bukharaeva, Ellya; Deiss-Yehiely, Nimrod; Dada, Laura A; Sachs, George; Fernandez-Salas, Ester; Vagin, Olga

2015-02-27

Septins are a family of 14 cytoskeletal proteins that dynamically form hetero-oligomers and organize membrane microdomains for protein complexes. The previously reported interactions with SNARE proteins suggested the involvement of septins in exocytosis. However, the contradictory results of up- or down-regulation of septin-5 in various cells and mouse models or septin-4 in mice suggested either an inhibitory or a stimulatory role for these septins in exocytosis. The involvement of the ubiquitously expressed septin-2 or general septin polymerization in exocytosis has not been explored to date. Here, by nano-LC with tandem MS and immunoblot analyses of the septin-2 interactome in mouse brain, we identified not only SNARE proteins but also Munc-18-1 (stabilizes assembled SNARE complexes), N-ethylmaleimide-sensitive factor (NSF) (disassembles SNARE complexes after each membrane fusion event), and the chaperones Hsc70 and synucleins (maintain functional conformation of SNARE proteins after complex disassembly). Importantly, α-soluble NSF attachment protein (SNAP), the adaptor protein that mediates NSF binding to the SNARE complex, did not interact with septin-2, indicating that septins undergo reorganization during each exocytosis cycle. Partial depletion of septin-2 by siRNA or impairment of septin dynamics by forchlorfenuron inhibited constitutive and stimulated exocytosis of secreted and transmembrane proteins in various cell types. Forchlorfenuron impaired the interaction between SNAP-25 and its chaperone Hsc70, decreasing SNAP-25 levels in cultured neuroendocrine cells, and inhibited both spontaneous and stimulated acetylcholine secretion in mouse motor neurons. The results demonstrate a stimulatory role of septin-2 and the dynamic reorganization of septin oligomers in exocytosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

ATG14 promotes membrane tethering and fusion of autophagosomes to endolysosomes.

PubMed

Diao, Jiajie; Liu, Rong; Rong, Yueguang; Zhao, Minglei; Zhang, Jing; Lai, Ying; Zhou, Qiangjun; Wilz, Livia M; Li, Jianxu; Vivona, Sandro; Pfuetzner, Richard A; Brunger, Axel T; Zhong, Qing

2015-04-23

Autophagy, an important catabolic pathway implicated in a broad spectrum of human diseases, begins by forming double membrane autophagosomes that engulf cytosolic cargo and ends by fusing autophagosomes with lysosomes for degradation. Membrane fusion activity is required for early biogenesis of autophagosomes and late degradation in lysosomes. However, the key regulatory mechanisms of autophagic membrane tethering and fusion remain largely unknown. Here we report that ATG14 (also known as beclin-1-associated autophagy-related key regulator (Barkor) or ATG14L), an essential autophagy-specific regulator of the class III phosphatidylinositol 3-kinase complex, promotes membrane tethering of protein-free liposomes, and enhances hemifusion and full fusion of proteoliposomes reconstituted with the target (t)-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) syntaxin 17 (STX17) and SNAP29, and the vesicle (v)-SNARE VAMP8 (vesicle-associated membrane protein 8). ATG14 binds to the SNARE core domain of STX17 through its coiled-coil domain, and stabilizes the STX17-SNAP29 binary t-SNARE complex on autophagosomes. The STX17 binding, membrane tethering and fusion-enhancing activities of ATG14 require its homo-oligomerization by cysteine repeats. In ATG14 homo-oligomerization-defective cells, autophagosomes still efficiently form but their fusion with endolysosomes is blocked. Recombinant ATG14 homo-oligomerization mutants also completely lose their ability to promote membrane tethering and to enhance SNARE-mediated fusion in vitro. Taken together, our data suggest an autophagy-specific membrane fusion mechanism in which oligomeric ATG14 directly binds to STX17-SNAP29 binary t-SNARE complex on autophagosomes and primes it for VAMP8 interaction to promote autophagosome-endolysosome fusion.

Wheat TaNPSN SNARE homologues are involved in vesicle-mediated resistance to stripe rust (Puccinia striiformis f. sp. tritici)

PubMed Central

Wang, Xiaodong; Wang, Xiaojie; Deng, Lin; Chang, Haitao; Dubcovsky, Jorge; Feng, Hao; Han, Qingmei; Huang, Lili; Kang, Zhensheng

2014-01-01

Subcellular localisation of SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) and their ability to form SNARE complexes are critical for determining the specificity of vesicle fusion. NPSN11, a Novel Plant SNARE (NPSN) gene, has been reported to be involved in the delivery of cell wall precursors to the newly formed cell plate during cytokinesis. However, functions of NPSN genes in plant–pathogen interactions are largely unknown. In this study, we cloned and characterized three NPSN genes (TaNPSN11, TaNPSN12, and TaNPSN13) and three plant defence-related SNARE homologues (TaSYP132, TaSNAP34, and TaMEMB12). TaSYP132 showed a highly specific interaction with TaNPSN11 in both yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays. We hypothesize that this interaction may indicate a partnership in vesicle trafficking. Expressions of the three TaNPSNs and TaSYP132 were differentially induced in wheat leaves when challenged by Puccinia striiformis f. sp. tritici (Pst). In virus-induced gene silencing (VIGS) assays, resistance of wheat (Triticum aestivum) cultivar Xingzi9104 to the Pst avirulent race CYR23 was reduced by knocking down TaNPSN11, TaNPSN13 and TaSYP132, but not TaNPSN12, implying diversified functions of these wheat SNARE homologues in prevention of Pst infection and hyphal elongation. Immuno-localization results showed that TaNPSN11 or its structural homologues were mainly distributed in vesicle structures near cell membrane toward Pst hypha. Taken together, our data suggests a role of TaNPSN11 in vesicle-mediated resistance to stripe rust. PMID:24963004

Blockade of the SNARE Protein Syntaxin 1 Inhibits Glioblastoma Tumor Growth

PubMed Central

Ulloa, Fausto; Gonzàlez-Juncà, Alba; Meffre, Delphine; Barrecheguren, Pablo José; Martínez-Mármol, Ramón; Pazos, Irene; Olivé, Núria; Cotrufo, Tiziana; Seoane, Joan; Soriano, Eduardo

2015-01-01

Glioblastoma (GBM) is the most prevalent adult brain tumor, with virtually no cure, and with a median overall survival of 15 months from diagnosis despite of the treatment. SNARE proteins mediate membrane fusion events in cells and are essential for many cellular processes including exocytosis and neurotransmission, intracellular trafficking and cell migration. Here we show that the blockade of the SNARE protein Syntaxin 1 (Stx1) function impairs GBM cell proliferation. We show that Stx1 loss-of-function in GBM cells, through ShRNA lentiviral transduction, a Stx1 dominant negative and botulinum toxins, dramatically reduces the growth of GBM after grafting U373 cells into the brain of immune compromised mice. Interestingly, Stx1 role on GBM progression may not be restricted just to cell proliferation since the blockade of Stx1 also reduces in vitro GBM cell invasiveness suggesting a role in several processes relevant for tumor progression. Altogether, our findings indicate that the blockade of SNARE proteins may represent a novel therapeutic tool against GBM. PMID:25803850

Insulin stimulates syntaxin4 SNARE complex assembly via a novel regulatory mechanism.

PubMed

Kioumourtzoglou, Dimitrios; Gould, Gwyn W; Bryant, Nia J

2014-04-01

Insulin stimulates glucose transport into fat and muscle cells by increasing the exocytic trafficking rate of the GLUT4 facilitative glucose transporter from intracellular stores to the plasma membrane. Delivery of GLUT4 to the plasma membrane is mediated by formation of functional SNARE complexes containing syntaxin4, SNAP23, and VAMP2. Here we have used an in situ proximity ligation assay to integrate these two observations by demonstrating for the first time that insulin stimulation causes an increase in syntaxin4-containing SNARE complex formation in adipocytes. Furthermore, we demonstrate that insulin brings about this increase in SNARE complex formation by mobilizing a pool of syntaxin4 held in an inactive state under basal conditions. Finally, we have identified phosphorylation of the regulatory protein Munc18c, a direct target of the insulin receptor, as a molecular switch to coordinate this process. Hence, this report provides molecular detail of how the cell alters membrane traffic in response to an external stimulus, in this case, insulin.

COPI mediates recycling of an exocytic SNARE by recognition of a ubiquitin sorting signal

PubMed Central

Xu, Peng; Hankins, Hannah M; MacDonald, Chris; Erlinger, Samuel J; Frazier, Meredith N; Diab, Nicholas S; Piper, Robert C; Jackson, Lauren P; MacGurn, Jason A

2017-01-01

The COPI coat forms transport vesicles from the Golgi complex and plays a poorly defined role in endocytic trafficking. Here we show that COPI binds K63-linked polyubiquitin and this interaction is crucial for trafficking of a ubiquitinated yeast SNARE (Snc1). Snc1 is a v-SNARE that drives fusion of exocytic vesicles with the plasma membrane, and then recycles through the endocytic pathway to the Golgi for reuse in exocytosis. Removal of ubiquitin from Snc1, or deletion of a β'-COP subunit propeller domain that binds K63-linked polyubiquitin, disrupts Snc1 recycling causing aberrant accumulation in internal compartments. Moreover, replacement of the β'-COP propeller domain with unrelated ubiquitin-binding domains restores Snc1 recycling. These results indicate that ubiquitination, a modification well known to target membrane proteins to the lysosome or vacuole for degradation, can also function as recycling signal to sort a SNARE into COPI vesicles in a non-degradative pathway. PMID:29058666

SNARE proteins underpin insulin-regulated GLUT4 traffic.

PubMed

Bryant, Nia J; Gould, Gwyn W

2011-06-01

Delivery of the glucose transporter type 4 (GLUT4) from an intracellular location to the cell surface in response to insulin represents a specialized form of membrane traffic, known to be impaired in the disease states of insulin resistance and type 2 diabetes. Like all membrane trafficking events, this translocation of GLUT4 requires members of the SNARE family of proteins. Here, we discuss two SNARE complexes that have been implicated in insulin-regulated GLUT4 traffic: one regulating the final delivery of GLUT4 to the cell surface in response to insulin and the other controlling GLUT4's intracellular trafficking. © 2011 John Wiley & Sons A/S.

CAPS and Munc13: CATCHRs that SNARE Vesicles.

PubMed

James, Declan J; Martin, Thomas F J

2013-12-04

CAPS (Calcium-dependent Activator Protein for Secretion, aka CADPS) and Munc13 (Mammalian Unc-13) proteins function to prime vesicles for Ca(2+)-triggered exocytosis in neurons and neuroendocrine cells. CAPS and Munc13 proteins contain conserved C-terminal domains that promote the assembly of SNARE complexes for vesicle priming. Similarities of the C-terminal domains of CAPS/Munc13 proteins with Complex Associated with Tethering Containing Helical Rods domains in multi-subunit tethering complexes (MTCs) have been reported. MTCs coordinate multiple interactions for SNARE complex assembly at constitutive membrane fusion steps. We review aspects of these diverse tethering and priming factors to identify common operating principles.

AMPLATZER versus Figulla occluder for transcatheter patent foramen ovale closure.

PubMed

Trabattoni, Daniela; Gaspardone, Achille; Sgueglia, Gregory A; Fabbiocchi, Franco; Gioffrè, Gaetano; Montorsi, Piero; Calligaris, Giuseppe; Iamele, Maria; De Santis, Antonella; Bartorelli, Antonio L

2017-04-20

The aim of this observational study was to compare acute and 12-month results of percutaneous closure of patent foramen ovale (PFO) with two occluder devices. Between June 2007 and October 2014, 406 consecutive patients (48.1±13.3 years, 243 women) underwent percutaneous PFO closure with either the AMPLATZER (n=179) or the Figulla (n=227) device after a stroke or a transient ischaemic attack ascribed to the PFO. A right-to-left shunt grade >1 was previously detected in all patients and atrial septal aneurysm was present in 111 (27.5%) patients. Patients were followed up with a contrast transthoracic echocardiogram and clinically at 24 hours, six months, and 12 months after the procedure. A high procedural success was observed in both groups. Despite a trend towards a higher incidence of acute residual shunt immediately after device deployment among Figulla occluder patients, a residual grade ≥2 right-to-left shunt was observed in 4.5% of patients, independently of the device used for PFO closure. The only difference reported after Figulla device implantation was a lower rate of supraventricular arrhythmias (9% vs. 17%, p=0.02). According to this two-centre study, PFO closure appears safe and effective with the Figulla occluder as well as with the AMPLATZER device.

Ventricular Septal Perforation after Biventricular Takotsubo Cardiomyopathy Successfully Repaired with an Amplatzer Device: First Report in the Literature.

PubMed

Rodríguez, Alfredo E; Fernandez-Pereira, Carlos; Mieres, Juan; Ascarrunz, Diego; Gabe, Eduardo; Rodríguez-Granillo, Alfredo Matías; Frattini, Romina; Stuzbach, Pablo

2016-01-01

A 79-year-old female was admitted with sudden onset dyspnea, mild oppressive chest pain, and severe anxiety disorder. Patient had history of hypertension, dyslipidemia, smoking, and chronic obstructive pulmonary disease. On admission blood pressure was 160/90 and heart rate was 130 bpm. Transthoracic echocardiography (TE) and contrast tomography showed a thin septum with an abnormal left and right ventricular contraction with an "apical ballooning" pattern and mild increase of cardiac enzymes. At the 4th day of admission, the patient presented symptoms and signs of congestive heart failure and developed cardiogenic shock. EKG showed an inversion of T waves in all precordial leads. In a new TE, a ventricular septal perforation (VSP) in the apical portion of the septum was seen. Coronary angiogram showed angiographically "normal" coronary arteries. With a diagnosis of VSP in takotsubo cardiomyopathy, a percutaneous procedure to repair the VSP was performed 11 days after admission. The VSP was closed with an Amplatzer device. TE performed 24 hours after showed significant improvement of ventricular function and good apposition of the Amplatzer device. Three days later she was discharged from the hospital. To our knowledge, this is the first reported case of a VSP in a TCM repaired percutaneously with an occluder device.

Productive and Non-productive Pathways for Synaptotagmin 1 to Support Ca2+-Triggered Fast Exocytosis.

PubMed

Kim, Jaewook; Shin, Yeon-Kyun

2017-01-01

Ca 2+ -triggered SNARE-mediated membrane fusion is essential for neuronal communication. The speed of this process is of particular importance because it sets a time limit to cognitive and physical activities. In this work, we expand the proteoliposome-to-supported bilayer (SBL) fusion assay by successfully incorporating synaptotagmin 1 (Syt1), a major Ca 2+ sensor. We report that Syt1 and Ca 2+ together can elicit more than a 50-fold increase in the number of membrane fusion events when compared with membrane fusion mediated by SNAREs only. What is remarkable is that ~55% of all vesicle fusion events occurs within 20 ms upon vesicle docking. Furthermore, pre-binding of Syt1 to SNAREs prior to Ca 2+ inhibits spontaneous fusion, but intriguingly, this leads to a complete loss of the Ca 2+ responsiveness. Thus, our results suggest that there is a productive and a non-productive pathway for Syt1, depending on whether there is a premature interaction between Syt1 and SNAREs. Our results show that Ca 2+ binding to Syt1 prior to Syt1's binding to SNAREs may be a prerequisite for the productive pathway. The successful reconstitution of Syt1 activities in the physiological time scale provides new opportunities to test the current mechanistic models for Ca 2+ -triggered exocytosis.

Preparation of the cortical reaction: maturation-dependent migration of SNARE proteins, clathrin, and complexin to the porcine oocyte's surface blocks membrane traffic until fertilization.

PubMed

Tsai, Pei-Shiue; van Haeften, Theo; Gadella, Bart M

2011-02-01

The cortical reaction is a calcium-dependent exocytotic process in which the content of secretory granules is released into the perivitellin space immediately after fertilization, which serves to prevent polyspermic fertilization. In this study, we investigated the involvement and the organization of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins in the docking and fusion of the cortical granule membrane with the oolemma in porcine oocytes. During meiotic maturation, secretory vesicles that were labeled with a granule-specific binding lectin, peanut agglutinin (PNA), migrated toward the oocyte's surface. This surface-orientated redistribution behavior was also observed for the oocyte-specific SNARE proteins SNAP23 and VAMP1 that colocalized with the PNA-labeled structures in the cortex area just under the oolemma and with the exclusive localization area of complexin (a trans-SNARE complex-stabilizing protein). The coming together of these proteins serves to prevent the spontaneous secretion of the docked cortical granules and to prepare the oocyte's surface for the cortical reaction, which should probably be immediately compensated for by a clathrin-mediated endocytosis. In vitro fertilization resulted in the secretion of the cortical granule content and the concomitant release of complexin and clathrin into the oocyte's cytosol, and this is considered to stimulate the observed endocytosis of SNARE-containing membrane vesicles.

Inhibition of Calpains Protects Mn-Induced Neurotransmitter release disorders in Synaptosomes from Mice: Involvement of SNARE Complex and Synaptic Vesicle Fusion.

PubMed

Wang, Can; Xu, Bin; Ma, Zhuo; Liu, Chang; Deng, Yu; Liu, Wei; Xu, Zhao-Fa

2017-06-16

Overexposure to manganese (Mn) could disrupt neurotransmitter release via influencing the formation of SNARE complex, but the underlying mechanisms are still unclear. A previous study demonstrated that SNAP-25 is one of substrate of calpains. The current study investigated whether calpains were involved in Mn-induced disorder of SNARE complex. After mice were treated with Mn for 24 days, Mn deposition increased significantly in basal nuclei in Mn-treated and calpeptin pre-treated groups. Behaviorally, less time spent in the center of the area and decreased average velocity significantly in an open field test after 24 days of Mn exposure. With the increase in MnCl 2 dosage, intracellular Ca 2+ increased significantly, but pretreatment with calpeptin caused a dose-dependent decrease in calpains activity. There were fragments of N-terminal of SNAP-25 protein appearance in Mn-treated groups, but it is decreased with pretreatment of calpeptin. FM1-43-labeled synaptic vesicles also provided evidence that the treatment with Mn resulted in increasing first and then decreasing, which was consistent with Glu release and the 80 kDa protein levels of SNARE complexes. In summary, Mn induced the disorder of neurotransmitter release through influencing the formation of SNARE complex via cleaving SNAP-25 by overactivation of calpains in vivo.

Amplatzer vascular plug for rapid vessel occlusion in interventional neuroradiology

PubMed Central

Banfield, Jillian C

2016-01-01

The purpose of this paper is to report different uses of endovascular Amplatzer vascular plug (AVP) treatment for rapid vessel occlusion in the field of interventional neuroradiology. We retrospectively reviewed our interventional neuroradiology database from November 2010 to July 2015 and found nine patients who were treated with endovascular AVP. AVP was used for rapid vessel occlusion of common carotid artery (1 patient), internal carotid artery (5 patients), vertebral artery (2 patients), and internal jugular vein (1 patient). A median of three AVPs were used with almost immediate occlusion and no thromboembolic complications. Use of AVP is feasible, safe, rapid, and potentially cost-effective method for rapid occlusion of larger size vessels in the head and neck region for different indications. PMID:26515699

Interventional Closure of a Patent Ductus Arteriosus Using an Amplatz Canine Duct Occluder in an Alpaca Cria.

PubMed

Chapel, E C; Lozier, J; Lakritz, J; Schober, K E

2017-07-01

A 6-month old female alpaca cria presented to The Ohio State University for evaluation of a cardiac murmur. Echocardiography revealed a left-to-right shunting patent ductus arteriosus, a restrictive left-to-right shunting perimembranous ventricular septal defect, and secondary moderate left atrial and ventricular dilation. Aortic root angiography demonstrated a type IIA patent ductus arteriosus (PDA). Interventional closure of the PDA was successfully performed, without complication, using an Amplatz canine duct occluder. This case report describes the materials and methods used for interventional closure of a PDA in an alpaca cria. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Observing the conformation of individual SNARE proteins inside live cells

NASA Astrophysics Data System (ADS)

Weninger, Keith

2010-10-01

Protein conformational dynamics are directly linked to function in many instances. Within living cells, protein dynamics are rarely synchronized so observing ensemble-averaged behaviors can hide details of signaling pathways. Here we present an approach using single molecule fluorescence resonance energy transfer (FRET) to observe the conformation of individual SNARE proteins as they fold to enter the SNARE complex in living cells. Proteins were recombinantly expressed, labeled with small-molecule fluorescent dyes and microinjected for in vivo imaging and tracking using total internal reflection microscopy. Observing single molecules avoids the difficulties of averaging over unsynchronized ensembles. Our approach is easily generalized to a wide variety of proteins in many cellular signaling pathways.

Further refinements of the polyp snare for interuterine surgery--a new modality for treatment of myomas and polyps.

PubMed

McLucas, B

1995-01-01

Hysteroscopic treatment of 30 patients suffering from menorrhagia or post-partum complications was accomplished using an electrosurgical polyp snare. Using this method, 18 polyps and 12 myomas were successfully removed in less than twenty minutes without complications. Local anaesthesia was used in 12 patients. Three patients have presented with recurrence of menorrhagia, with a minimum of six months follow-up. Benefits of this technique compared to uterine resectoscopy include shorter operative time, decreased risk of fluid overload, and less risk of uterine perforation. The snare is difficult to use and a learning curve exists. Higher currents than that used for resection are required.

TANGO1 recruits ERGIC membranes to the endoplasmic reticulum for procollagen export

PubMed Central

Santos, António JM; Raote, Ishier; Scarpa, Margherita; Brouwers, Nathalie; Malhotra, Vivek

2015-01-01

Previously we showed that membrane fusion is required for TANGO1-dependent export of procollagen VII from the endoplasmic reticulum (ER) (Nogueira, et al., 2014). Along with the t-SNARE Syntaxin 18, we now reveal the complete complement of SNAREs required in this process, t-SNAREs BNIP1 and USE1, and v-SNARE YKT6. TANGO1 recruits YKT6-containing ER Golgi Intermediate Compartment (ERGIC) membranes to procollagen VII-enriched patches on the ER. Moreover residues 1214-1396, that include the first coiled coil of TANGO1, specifically recruit ERGIC membranes even when targeted to mitochondria. TANGO1 is thus pivotal in concentrating procollagen VII in the lumen and recruiting ERGIC membranes on the cytoplasmic surface of the ER. Our data reveal that growth of a mega transport carrier for collagen export from the ER is not by acquisition of a larger patch of ER membrane, but instead by addition of ERGIC membranes to procollagen-enriched domains of the ER by a TANGO1-mediated process. DOI: http://dx.doi.org/10.7554/eLife.10982.001 PMID:26568311

NSF- and SNARE-mediated membrane fusion is required for nuclear envelope formation and completion of nuclear pore complex assembly in Xenopus laevis egg extracts.

PubMed

Baur, Tina; Ramadan, Kristijan; Schlundt, Andreas; Kartenbeck, Jürgen; Meyer, Hemmo H

2007-08-15

Despite the progress in understanding nuclear envelope (NE) reformation after mitosis, it has remained unclear what drives the required membrane fusion and how exactly this is coordinated with nuclear pore complex (NPC) assembly. Here, we show that, like other intracellular fusion reactions, NE fusion in Xenopus laevis egg extracts is mediated by SNARE proteins that require activation by NSF. Antibodies against Xenopus NSF, depletion of NSF or the dominant-negative NSF(E329Q) variant specifically inhibited NE formation. Staging experiments further revealed that NSF was required until sealing of the envelope was completed. Moreover, excess exogenous alpha-SNAP that blocks SNARE function prevented membrane fusion and caused accumulation of non-flattened vesicles on the chromatin surface. Under these conditions, the nucleoporins Nup107 and gp210 were fully recruited, whereas assembly of FxFG-repeat-containing nucleoporins was blocked. Together, we define NSF- and SNARE-mediated membrane fusion events as essential steps during NE formation downstream of Nup107 recruitment, and upstream of membrane flattening and completion of NPC assembly.

Regulation of exocytosis by the exocyst subunit Sec6 and the SM protein Sec1.

PubMed

Morgera, Francesca; Sallah, Margaret R; Dubuke, Michelle L; Gandhi, Pallavi; Brewer, Daniel N; Carr, Chavela M; Munson, Mary

2012-01-01

Trafficking of protein and lipid cargo through the secretory pathway in eukaryotic cells is mediated by membrane-bound vesicles. Secretory vesicle targeting and fusion require a conserved multisubunit protein complex termed the exocyst, which has been implicated in specific tethering of vesicles to sites of polarized exocytosis. The exocyst is directly involved in regulating soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) complexes and membrane fusion through interactions between the Sec6 subunit and the plasma membrane SNARE protein Sec9. Here we show another facet of Sec6 function-it directly binds Sec1, another SNARE regulator, but of the Sec1/Munc18 family. The Sec6-Sec1 interaction is exclusive of Sec6-Sec9 but compatible with Sec6-exocyst assembly. In contrast, the Sec6-exocyst interaction is incompatible with Sec6-Sec9. Therefore, upon vesicle arrival, Sec6 is proposed to release Sec9 in favor of Sec6-exocyst assembly and to simultaneously recruit Sec1 to sites of secretion for coordinated SNARE complex formation and membrane fusion.

The primed SNARE–complexin–synaptotagmin complex for neuronal exocytosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Qiangjun; Zhou, Peng; Wang, Austin L.

Synaptotagmin, complexin, and neuronal SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins mediate evoked synchronous neurotransmitter release, but the molecular mechanisms mediating the cooperation between these molecules remain unclear. Here we determine crystal structures of the primed pre-fusion SNARE–complexin–synaptotagmin-1 complex. These structures reveal an unexpected tripartite interface between synaptotagmin-1 and both the SNARE complex and complexin. Simultaneously, a second synaptotagmin-1 molecule interacts with the other side of the SNARE complex via the previously identified primary interface. Mutations that disrupt either interface in solution also severely impair evoked synchronous release in neurons, suggesting that both interfaces are essential for themore » primed pre-fusion state. Ca 2+ binding to the synaptotagmin-1 molecules unlocks the complex, allows full zippering of the SNARE complex, and triggers membrane fusion. In conclusion, the tripartite SNARE–complexin–synaptotagmin-1 complex at a synaptic vesicle docking site has to be unlocked for triggered fusion to start, explaining the cooperation between complexin and synaptotagmin-1 in synchronizing evoked release on the sub-millisecond timescale.« less

The primed SNARE–complexin–synaptotagmin complex for neuronal exocytosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Qiangjun; Zhou, Peng; Wang, Austin L.

Synaptotagmin, complexin, and neuronal SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins mediate evoked synchronous neurotransmitter release, but the molecular mechanisms mediating the cooperation between these molecules remain unclear. Here we determine crystal structures of the primed pre-fusion SNARE–complexin–synaptotagmin-1 complex. These structures reveal an unexpected tripartite interface between synaptotagmin-1 and both the SNARE complex and complexin. Simultaneously, a second synaptotagmin-1 molecule interacts with the other side of the SNARE complex via the previously identified primary interface. Mutations that disrupt either interface in solution also severely impair evoked synchronous release in neurons, suggesting that both interfaces are essential for themore » primed pre-fusion state. Ca2+ binding to the synaptotagmin-1 molecules unlocks the complex, allows full zippering of the SNARE complex, and triggers membrane fusion. The tripartite SNARE–complexin–synaptotagmin-1 complex at a synaptic vesicle docking site has to be unlocked for triggered fusion to start, explaining the cooperation between complexin and synaptotagmin-1 in synchronizing evoked release on the sub-millisecond timescale.« less

The primed SNARE–complexin–synaptotagmin complex for neuronal exocytosis

DOE PAGES

Zhou, Qiangjun; Zhou, Peng; Wang, Austin L.; ...

2017-08-16

Synaptotagmin, complexin, and neuronal SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins mediate evoked synchronous neurotransmitter release, but the molecular mechanisms mediating the cooperation between these molecules remain unclear. Here we determine crystal structures of the primed pre-fusion SNARE–complexin–synaptotagmin-1 complex. These structures reveal an unexpected tripartite interface between synaptotagmin-1 and both the SNARE complex and complexin. Simultaneously, a second synaptotagmin-1 molecule interacts with the other side of the SNARE complex via the previously identified primary interface. Mutations that disrupt either interface in solution also severely impair evoked synchronous release in neurons, suggesting that both interfaces are essential for themore » primed pre-fusion state. Ca 2+ binding to the synaptotagmin-1 molecules unlocks the complex, allows full zippering of the SNARE complex, and triggers membrane fusion. In conclusion, the tripartite SNARE–complexin–synaptotagmin-1 complex at a synaptic vesicle docking site has to be unlocked for triggered fusion to start, explaining the cooperation between complexin and synaptotagmin-1 in synchronizing evoked release on the sub-millisecond timescale.« less

In Situ Proximity Ligation Assay Reveals Co-Localization of Alpha-Synuclein and SNARE Proteins in Murine Primary Neurons.

PubMed

Almandoz-Gil, Leire; Persson, Emma; Lindström, Veronica; Ingelsson, Martin; Erlandsson, Anna; Bergström, Joakim

2018-01-01

The aggregation of alpha-synuclein (αSyn) is the pathological hallmark of Parkinson's disease, dementia with Lewy bodies and related neurological disorders. However, the physiological function of the protein and how this function relates to its pathological effects remain poorly understood. One of the proposed roles of αSyn is to promote the soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex assembly by binding to VAMP-2. The objective of this study was to visualize the co-localization between αSyn and the SNARE proteins (VAMP-2, SNAP-25, and syntaxin-1) for the first time using in situ proximity ligation assay (PLA). Cortical primary neurons were cultured from either non-transgenic or transgenic mice expressing human αSyn with the A30P mutation under the Thy-1 promoter. With an antibody recognizing both mouse and human αSyn, a PLA signal indicating close proximity between αSyn and the three SNARE proteins was observed both in the soma and throughout the processes. No differences in the extent of PLA signals were seen between non-transgenic and transgenic neurons. With an antibody specific against human αSyn, the PLA signal was mostly located to the soma and was only present in a few cells. Taken together, in situ PLA is a method that can be used to investigate the co-localization of αSyn and the SNARE proteins in primary neuronal cultures.

SNARE-mediated rapid lysosome fusion in membrane raft clustering and dysfunction of bovine coronary arterial endothelium

PubMed Central

Han, Wei-Qing; Xia, Min; Zhang, Chun; Zhang, Fan; Xu, Ming; Li, Ning-Jun

2011-01-01

The present study attempted to evaluate whether soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) mediate lysosome fusion in response to death receptor activation and contribute to membrane raft (MR) clustering and consequent endothelial dysfunction in coronary arterial endothelial cells. By immunohistochemical analysis, vesicle-associated membrane proteins 2 (VAMP-2, vesicle-SNAREs) were found to be abundantly expressed in the endothelium of bovine coronary arteries. Direct lysosome fusion monitoring by N-(3-triethylammoniumpropyl)-4-[4-(dibutylamino)styryl]pyridinium dibromide (FM1-43) quenching demonstrated that the inhibition of VAMP-2 with tetanus toxin or specific small interfering ribonucleic acid (siRNA) almost completely blocked lysosome fusion to plasma membrane induced by Fas ligand (FasL), a well-known MR clustering stimulator. The involvement of SNAREs was further confirmed by an increased interaction of VAMP-2 with a target-SNARE protein syntaxin-4 after FasL stimulation in coimmunoprecipitation analysis. Also, the inhibition of VAMP-2 with tetanus toxin or VAMP-2 siRNA abolished FasL-induced MR clustering, its colocalization with a NADPH oxidase unit gp91phox, and increased superoxide production. Finally, FasL-induced impairment of endothelium-dependent vasodilation was reversed by the treatment of bovine coronary arteries with tetanus toxin or VAMP-2 siRNA. VAMP-2 is critical to lysosome fusion in MR clustering, and this VAMP-2-mediated lysosome-MR signalosomes contribute to redox regulation of coronary endothelial function. PMID:21926345

Prospective randomized comparison of cold snare polypectomy and conventional polypectomy for small colorectal polyps.

PubMed

Ichise, Yasuyuki; Horiuchi, Akira; Nakayama, Yoshiko; Tanaka, Naoki

2011-01-01

The ideal method to remove small colorectal polyps is unknown. We compared removal by colon snare transection without electrocautery (cold snare polypectomy) with conventional electrocautery snare polypectomy (hot polypectomy) in terms of procedure duration, difficulty in retrieving polyps, bleeding, and post-polypectomy symptoms. Patients with colorectal polyps up to 8 mm in diameter were randomized to polypectomy by cold snare technique (cold group) or conventional polypectomy (conventional group). The principal outcome measures were abdominal symptoms within 2 weeks after polypectomy. Secondary outcome measures were the rates of retrieval of colorectal polyps and bleeding. Eighty patients were randomized: cold group, n = 40 (101 polyps) and conventional group, n = 40 (104 polyps). The patients' demographic characteristics and the number and size of polyps removed were similar between the two techniques. Procedure time was significantly shorter with cold polypectomy vs. conventional polypectomy (18 vs. 25 min, p < 0.0001). Complete polyp retrieval rates were identical [96% (97/101) vs. 96% (100/104)]. No bleeding requiring hemostasis occurred in either group. Abdominal symptoms shortly after polypectomy were more common with conventional polypectomy (i.e. 20%; 8/40) than with cold polypectomy (i.e. 2.5%; 1/40; p = 0.029). Cold polypectomy was superior to conventional polypectomy in terms of procedure time and post-polypectomy abdominal symptoms. The two methods were otherwise essentially identical in terms of bleeding risk and complete polyp retrieval. Cold polypectomy is therefore the preferred method for removal of small colorectal polyps. Copyright © 2011 S. Karger AG, Basel.

Regulation of Exocytotic Fusion Pores by SNARE Protein Transmembrane Domains

PubMed Central

Wu, Zhenyong; Thiyagarajan, Sathish; O’Shaughnessy, Ben; Karatekin, Erdem

2017-01-01

Calcium-triggered exocytotic release of neurotransmitters and hormones from neurons and neuroendocrine cells underlies neuronal communication, motor activity and endocrine functions. The core of the neuronal exocytotic machinery is composed of soluble N-ethyl maleimide sensitive factor attachment protein receptors (SNAREs). Formation of complexes between vesicle-attached v- and plasma-membrane anchored t-SNAREs in a highly regulated fashion brings the membranes into close apposition. Small, soluble proteins called Complexins (Cpx) and calcium-sensing Synaptotagmins cooperate to block fusion at low resting calcium concentrations, but trigger release upon calcium increase. A growing body of evidence suggests that the transmembrane domains (TMDs) of SNARE proteins play important roles in regulating the processes of fusion and release, but the mechanisms involved are only starting to be uncovered. Here we review recent evidence that SNARE TMDs exert influence by regulating the dynamics of the fusion pore, the initial aqueous connection between the vesicular lumen and the extracellular space. Even after the fusion pore is established, hormone release by neuroendocrine cells is tightly controlled, and the same may be true of neurotransmitter release by neurons. The dynamics of the fusion pore can regulate the kinetics of cargo release and the net amount released, and can determine the mode of vesicle recycling. Manipulations of SNARE TMDs were found to affect fusion pore properties profoundly, both during exocytosis and in biochemical reconstitutions. To explain these effects, TMD flexibility, and interactions among TMDs or between TMDs and lipids have been invoked. Exocytosis has provided the best setting in which to unravel the underlying mechanisms, being unique among membrane fusion reactions in that single fusion pores can be probed using high-resolution methods. An important role will likely be played by methods that can probe single fusion pores in a biochemically defined setting which have recently become available. Finally, computer simulations are valuable mechanistic tools because they have the power to access small length scales and very short times that are experimentally inaccessible. PMID:29066949

Frontotemporal dysregulation of the SNARE protein interactome is associated with faster cognitive decline in old age.

PubMed

Ramos-Miguel, Alfredo; Jones, Andrea A; Sawada, Ken; Barr, Alasdair M; Bayer, Thomas A; Falkai, Peter; Leurgans, Sue E; Schneider, Julie A; Bennett, David A; Honer, William G

2018-06-01

The molecular underpinnings associated with cognitive reserve remain poorly understood. Because animal models fail to fully recapitulate the complexity of human brain aging, postmortem studies from well-designed cohorts are crucial to unmask mechanisms conferring cognitive resistance against cumulative neuropathologies. We tested the hypothesis that functionality of the SNARE protein interactome might be an important resilience factor preserving cognitive abilities in old age. Cognition was assessed annually in participants from the Rush "Memory and Aging Project" (MAP), a community-dwelling cohort representative of the overall aging population. Associations between cognition and postmortem neurochemical data were evaluated in functional assays quantifying various species of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) machinery in samples from the inferior temporal (IT, n = 154) and middle-frontal (MF, n = 174) gyri. Using blue-native gel electrophoresis, we isolated and quantified several types of complexes containing the three SNARE proteins (syntaxin-1, SNAP25, VAMP), as well as the GABAergic/glutamatergic selectively expressed complexins-I/II (CPLX1/2), in brain tissue homogenates and reconstitution assays with recombinant proteins. Multivariate analyses revealed significant associations between IT and MF neurochemical data (SNARE proteins and/or complexes), and multiple age-related neuropathologies, as well as with multiple cognitive domains of MAP participants. Controlling for demographic variables, neuropathologic indices and total synapse density, we found that temporal 150-kDa SNARE species (representative of pan-synaptic functionality) and frontal CPLX1/CPLX2 ratio of 500-kDa heteromeric species (representative of inhibitory/excitatory input functionality) were, among all the immunocharacterized complexes, the strongest predictors of cognitive function nearest death. Interestingly, these two neurochemical variables were associated with different cognitive domains. In addition, linear mixed effect models of global cognitive decline estimated that both 150-kDa SNARE levels and CPLX1/CPLX2 ratio were associated with better cognition and less decline over time. The results are consistent with previous studies reporting that synapse dysfunction (i.e. dysplasticity) may be initiated early, and relatively independent of neuropathology-driven synapse loss. Frontotemporal dysregulation of the GABAergic/glutamatergic stimuli might be a target for future drug development. Copyright © 2018 Elsevier Inc. All rights reserved.

Hybrid approach to surgical correction of tetralogy of Fallot in all patients with functioning Blalock Taussig shunts.

PubMed

Sivakumar, Kothandam; Krishnan, Prasad; Pieris, Rajeeva; Francis, Edwin

2007-08-01

In total surgical correction of tetralogy of Fallot (TOF) with functioning Blalock Taussig shunts (BTS), shunt take down increased surgical time, bleeding, and might injure phrenic and recurrent laryngeal nerve and thoracic duct. A routine hybrid approach using transcatheter BTS closure immediately before total surgical correction of TOF in all patients might reduce these problems. We analyze the safety and feasibility of this approach. Transcatheter BTS closure was achieved using single or multiple stainless steel embolization coils, Amplatzer vascular plugs, or duct occluders. When coils were released without control by bioptome forceps, coil migration in larger shunts was prevented by proximal or distal balloon occlusion. This routine hybrid strategy was followed in 22 consecutive patients aged 1-13 years over 4-year-period and 21 procedures were successful. Among the 16 patients attempted with coils, 13 had successful closure, 2 needed Amplatzer duct occluder devices, and 1 sent for surgical shunt takedown due to acute angulation of the shunt. New Amplatzer vascular plugs were used in six patients. Bioptome was used in six patients and proximal or distal balloon occlusion of flow was used in three patients. Four patients had closure of associated aortopulmonary or chest wall collaterals. Hybrid approach using routine transcatheter closure of all BTS immediately before surgical correction of TOF shunts with coils/plugs/devices is safe, feasible, and reproducible. Copyright (c) 2007 Wiley-Liss, Inc.

Advantages and Disadvantages of the Amplatzer Vascular Plug IV in Visceral Embolization: Report of 50 Placements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pech, Maciej, E-mail: maciej.pech@med.ovgu.de; Mohnike, Konrad; Wieners, Gero

2011-10-15

Purpose: We describe our initial clinical experience in artificial embolization with the Amplatzer Vascular Plug IV (VP IV), a further development of the Vascular Plug family already in routine use. Methods: Results from 50 embolization procedures conducted with the VP IV in 44 patients are summarized. Results: All 50 embolizations were successful, although two required the technique to be modified because of problems with jamming of the screw thread and thus with disconnection of the plug. This was associated with large branching angles. Conclusions: With experience, the VP IV can be used safely and effectively, and it expands the spectrummore » of possible embolizations in interventional radiology. Its greatest disadvantage is its relatively poor positional controllability.« less

Aneurysm of an Anomalous Systemic Artery Supplying the Normal Basal Segments of the Left Lower Lobe: Endovascular Treatment with the Amplatzer Vascular Plug II and Coils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canyigit, Murat, E-mail: mcanyigit@yahoo.com; Gumus, Mehmet; Kilic, Evrim

2011-02-15

An anomalous systemic artery originating from the descending thoracic aorta supplying the normal basal segments of the lower lobe of the left lung without sequestration is a rare congenital anomaly. The published surgical treatments include lobectomy, segmentectomy, anastomosis, and ligation. In addition, endovascular treatment with coils has been reported. A second-generation occluder, the Amplatzer Vascular Plug II (AVP II), has a central plug and two occlusion disks and a finer, more densely woven nitinol wire, thus enabling faster embolization. This published case is the first successful occlusion of an aneurysm of an anomalous systemic artery with the AVP II andmore » fibered coils, with 10 months of follow-up.« less

Percutaneous treatment of atrial septal defects, muscular ventricular septal defects and patent ductus arteriosus in infants under one year of age.

PubMed

Prada, Fredy; Mortera, Carlos; Bartrons, Joaquim; Rissech, Miguel; Jiménez, Lorenzo; Carretero, Juan; Llevadias, Judit; Araica, Mireya

2009-09-01

Amplatzer devices are used for the percutaneous closure of ostium secundum atrial septal defects, muscular ventricular septal defects and patent ductus arteriosus. However, very little experience has been gained in using these devices in infants under 1 year of age. Between January 2001 and January 2008, 22 symptomatic infants aged under 1 year underwent percutaneous treatment: three had an ostium secundum atrial septal defect, 15 had patent ductus arteriosus, and four had a muscular ventricular septal defect. All the procedures were completed successfully. No immediate or medium-term complications were observed. Closure of these types of defect using an Amplatzer device in infants under 1 year of age, who would otherwise require surgery, is a safe and effective procedure.

Oligomerisation of Synaptobrevin-2 Studied by Native Mass Spectrometry and Chemical Cross-Linking

NASA Astrophysics Data System (ADS)

Wittig, Sabine; Haupt, Caroline; Hoffmann, Waldemar; Kostmann, Susann; Pagel, Kevin; Schmidt, Carla

2018-06-01

Synaptobrevin-2 is a key player in signal transmission in neurons. It forms, together with SNAP25 and Syntaxin-1A, the neuronal soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and mediates exocytosis of synaptic vesicles with the pre-synaptic membrane. While Synaptobrevin-2 is part of a four-helix bundle in this SNARE complex, it is natively unstructured in the absence of lipids or other SNARE proteins. Partially folded segments, presumably SNARE complex formation intermediates, as well as formation of Synaptobrevin-2 dimers and oligomers, were identified in previous studies. Here, we employ three Synaptobrevin-2 variants—the full-length protein Syb(1-116), the soluble, cytosolic variant Syb(1-96) as well as a shorter version Syb(49-96) containing structured segments but omitting a trigger site for SNARE complex formation—to study oligomerisation in the absence of interaction partners or when incorporated into the lipid bilayer of liposomes. Combining native mass spectrometry with chemical cross-linking, we find that the truncated versions show increased oligomerisation. Our findings from both techniques agree well and confirm the presence of oligomers in solution while membrane-bound Synaptobrevin-2 is mostly monomeric. Using ion mobility mass spectrometry, we could further show that lower charge states of Syb(49-96) oligomers, which most likely represent solution structures, follow an isotropic growth curve suggesting that they are intrinsically disordered. From a technical point of view, we show that the combination of native ion mobility mass spectrometry with chemical cross-linking is well-suited for the analysis of protein homo-oligomers. [Figure not available: see fulltext.

Efficacy of lures and hair snares to detect lynx

Treesearch

Gregory W. McDaniel; Kevin S. McKelvey; John R. Squires; Leonard F. Ruggiero

2000-01-01

Resource managers lack an inexpensive and quantifiable method to detect lynx presence across large landscapes. We tested efficacy of a protocol based on hair snagging to detect presence of lynx (Lynx canadensis). We tested 2 key elements of the protocol: 1) a hair-snaring device and 2) commercial lures used to attract and elicit rubbing behavior in lynx. The...

Comparing scat detection dogs, cameras, and hair snares for surveying carnivores

USGS Publications Warehouse

Long, Robert A.; Donovan, T.M.; MacKay, Paula; Zielinski, William J.; Buzas, Jeffrey S.

2007-01-01

Carnivores typically require large areas of habitat, exist at low natural densities, and exhibit elusive behavior - characteristics that render them difficult to study. Noninvasive survey methods increasingly provide means to collect extensive data on carnivore occupancy, distribution, and abundance. During the summers of 2003-2004, we compared the abilities of scat detection dogs, remote cameras, and hair snares to detect black bears (Ursus americanus), fishers (Martes pennanti), and bobcats (Lynx rufus) at 168 sites throughout Vermont. All 3 methods detected black bears; neither fishers nor bobcats were detected by hair snares. Scat detection dogs yielded the highest raw detection rate and probability of detection (given presence) for each of the target species, as well as the greatest number of unique detections (i.e., occasions when only one method detected the target species). We estimated that the mean probability of detecting the target species during a single visit to a site with a detection dog was 0.87 for black bears, 0.84 for fishers, and 0.27 for bobcats. Although the cost of surveying with detection dogs was higher than that of remote cameras or hair snares, the efficiency of this method rendered it the most cost-effective survey method.

BAG3 regulates formation of the SNARE complex and insulin secretion

PubMed Central

Iorio, V; Festa, M; Rosati, A; Hahne, M; Tiberti, C; Capunzo, M; De Laurenzi, V; Turco, M C

2015-01-01

Insulin release in response to glucose stimulation requires exocytosis of insulin-containing granules. Glucose stimulation of beta cells leads to focal adhesion kinase (FAK) phosphorylation, which acts on the Rho family proteins (Rho, Rac and Cdc42) that direct F-actin remodeling. This process requires docking and fusion of secretory vesicles to the release sites at the plasma membrane and is a complex mechanism that is mediated by SNAREs. This transiently disrupts the F-actin barrier and allows the redistribution of the insulin-containing granules to more peripheral regions of the β cell, hence facilitating insulin secretion. In this manuscript, we show for the first time that BAG3 plays an important role in this process. We show that BAG3 downregulation results in increased insulin secretion in response to glucose stimulation and in disruption of the F-actin network. Moreover, we show that BAG3 binds to SNAP-25 and syntaxin-1, two components of the t-SNARE complex preventing the interaction between SNAP-25 and syntaxin-1. Upon glucose stimulation BAG3 is phosphorylated by FAK and dissociates from SNAP-25 allowing the formation of the SNARE complex, destabilization of the F-actin network and insulin release. PMID:25766323

Usefulness of a multifunctional snare designed for colorectal hybrid endoscopic submucosal dissection (with video).

PubMed

Ohata, Ken; Muramoto, Takashi; Minato, Yohei; Chiba, Hideyuki; Sakai, Eiji; Matsuhashi, Nobuyuki

2018-02-01

Since colorectal endoscopic submucosal dissection (ESD) remains technically difficult, hybrid ESD was developed as an alternative therapeutic option to achieve en bloc resection of relatively large lesions. In this feasibility study, we evaluated the safety and efficacy of hybrid colorectal ESD using a newly developed multifunctional snare. From June to August 2016, we prospectively enrolled 10 consecutive patients with non-pedunculated intramucosal colorectal tumors 20 - 30 mm in diameter. All of the hybrid ESD steps were performed using the "SOUTEN" snare. The knob-shaped tip attached to the loop top helps to stabilize the needle-knife, making it less likely to slip during circumferential incision and enables partial submucosal dissection. All of the lesions were curatively resected by hybrid ESD, with a short mean procedure time (16.1 ± 4.8 minutes). The mean diameters of the resected specimens and tumors were 30.5 ± 4.9 and 26.0 ± 3.5 mm, respectively. No perforations occurred, while delayed bleeding occurred in 1 patient. In conclusion, hybrid ESD using a multifunctional snare enables easy, safe, and cost-effective resection of relatively large colorectal tumors to be achieved. UMIN000022545.

Cellular and molecular mechanism for secretory autophagy.

PubMed

Kimura, Tomonori; Jia, Jingyue; Claude-Taupin, Aurore; Kumar, Suresh; Choi, Seong Won; Gu, Yuexi; Mudd, Michal; Dupont, Nicolas; Jiang, Shanya; Peters, Ryan; Farzam, Farzin; Jain, Ashish; Lidke, Keith A; Adams, Christopher M; Johansen, Terje; Deretic, Vojo

2017-06-03

Macroautophagy/autophagy plays a role in unconventional secretion of leaderless cytosolic proteins. Whether and how secretory autophagy diverges from conventional degradative autophagy is unclear. We have shown that the prototypical secretory autophagy cargo IL1B/IL-1β (interleukin 1 β) is recognized by TRIM16, and that this first to be identified secretory autophagy receptor interacts with the R-SNARE SEC22B to jointly deliver cargo to the MAP1LC3B-II-positive sequestration membranes. Cargo secretion is unaffected by knockdowns of STX17, a SNARE catalyzing autophagosome-lysosome fusion as a prelude to cargo degradation. Instead, SEC22B in combination with plasma membrane syntaxins completes cargo secretion. Thus, secretory autophagy diverges from degradative autophagy by using specialized receptors and a dedicated SNARE machinery to bypass fusion with lysosomes.

Delayed Infective Endocarditis with Mycotic Aneurysm Rupture below the Mechanical Valved Conduit after the Bentall Procedure.

PubMed

Chen, Mei-Ling; Chen, Michael Y; Yin, Wei-Hsian; Wei, Jeng; Wang, Ji-Hung

2014-07-01

The Bentall procedure is the gold standard for treating aortic dissection complicated with valvular and ascending aorta disease. Recent results for this procedure have been excellent; nearly 100% of patients remain free of infective endocarditis in long-term follow-up. We report a case of delayed Streptococcus agalactiae infective endocarditis complicated by mycotic aneurysm in a man who had undergone the Bentall procedure with a mechanical valve conduit 15 years previously. The mycotic aneurysm was located in the remnant aortic root, below the mechanical valve conduit, and later ruptured into the right atrium. The patient was treated conservatively and survived the acute period. Later, the aortic root defect was repaired successfully by means of a hybrid technique using a Amplatzer duct occluder. Amplatzer duct occluder; Aortic dissection; Bentall technique; Infective endocarditis; Mycotic aneurysm.

Amplatzer vascular plug for arteriovenous hemodialysis access occlusion: initial experience.

PubMed

Bui, J T; Gaba, R C; Knuttinen, M G; West, D L; Owens, C A

2009-01-01

The Amplatzer Vascular Plug (AVP; AGA Medical, Golden Valley, MN) is a recently developed self-expanding metallic device indicated for peripheral vascular embolizations. Herein, we describe use of this device in the treatment of vascular complications related to arteriovenous hemodialysis fistulas and grafts. This HIPAA compliant retrospective study was approved by the institutional review board with informed consent waived. Six patients with problematic arteriovenous access underwent access occlusion using the AVP. Procedure indications included vascular steal syndrome in five patients, and enlarging vascular aneurysms in one patient. Contraindications for surgical correction were determined by the referring surgeon. AVP embolizations were performed using devices oversized by 50% introduced through vascular sheaths positioned within vein segments just beyond the arteriovenous anastomoses. Noninvasive evaluation of the involved extremity was performed pre- and post-embolization in addition to clinical follow-up examinations. Measured outcomes included success of angiographic occlusion, improvement in distal arterial flow, AVP number, AVP diameter, time to access occlusion, and clinical symptomatic improvement. Technical success was 100%, with complete arteriovenous access occlusion accomplished in all cases, with an average of 1.5 AVPs used per patient. Mean time to access occlusion was 19.3 minutes. Angiographic improvement in distal arterial flow was immediately evident and resolution of clinical symptoms occurred in all patients, with mean long-term follow-up of 16 months. No procedure-related complications were encountered. The Amplatzer Vascular Plug provides a minimally invasive and efficacious method for embolization of problematic arteriovenous hemodialysis access.

[Percutaneous closure of atrial septal defects with the Amplatzer® device: 15 years of experience].

PubMed

Zabal-Cerdeira, Carlos; García-Montes, José Antonio; Sandoval-Jones, Juan Pablo; Calderón-Colmenero, Juan; Patiño-Bahena, Emilia; Juanico-Enríquez, Antonio; Buendía-Hernández, Alfonso

2014-01-01

Percutaneous closure of atrial septal defects is an alternative to surgical treatment. We report the results of percutaneous closure of atrial septal defects with the Amplatzer(®) device. We include patients taken to the catheterization laboratory from September 1997 to December 2011. We proceeded with defect closure in 721 patients and in 85 the defect was considered not suitable for closure. The stretched diameter of the defect was 23±6.7mm (limits, 5-42). All devices were positioned successfully. In 15 cases (2.1%) the device was changed due to instability and in 6 (0.8%) the device embolized within the first 24h, 4 were retrieved and repositioned (final success with intention to treat 719/806-89.2%). Immediate control showed complete closure in 247 patients (34.3%), leak through the device in 395 (54.9%), mild residual leak in 75 (10.4%) and moderate in 2 (0.3%). We have follow-up in 626 patients (87.1%) for 33±27.5 months, with headache in 54 (8.6%), new supraventricular arrhythmia in 10 (1.6%), puncture site complications in 4 (0.6%), and stroke in one (0.1%). The design of the Amplatzer(®) device allows effective closure of atrial septal defects with a simple technique and patient safety. Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

Membrane fusion and exocytosis.

PubMed

Jahn, R; Südhof, T C

1999-01-01

Membrane fusion involves the merger of two phospholipid bilayers in an aqueous environment. In artificial lipid bilayers, fusion proceeds by means of defined transition states, including hourglass-shaped intermediates in which the proximal leaflets of the fusing membranes are merged whereas the distal leaflets are separate (fusion stalk), followed by the reversible opening of small aqueous fusion pores. Fusion of biological membranes requires the action of specific fusion proteins. Best understood are the viral fusion proteins that are responsible for merging the viral with the host cell membrane during infection. These proteins undergo spontaneous and dramatic conformational changes upon activation. In the case of the paradigmatic fusion proteins of the influenza virus and of the human immunodeficiency virus, an amphiphilic fusion peptide is inserted into the target membrane. The protein then reorients itself, thus forcing the fusing membranes together and inducing lipid mixing. Fusion of intracellular membranes in eukaryotic cells involves several protein families including SNAREs, Rab proteins, and Sec1/Munc-18 related proteins (SM-proteins). SNAREs form a novel superfamily of small and mostly membrane-anchored proteins that share a common motif of about 60 amino acids (SNARE motif). SNAREs reversibly assemble into tightly packed helical bundles, the core complexes. Assembly is thought to pull the fusing membranes closely together, thus inducing fusion. SM-proteins comprise a family of soluble proteins that bind to certain types of SNAREs and prevent the formation of core complexes. Rab proteins are GTPases that undergo highly regulated GTP-GDP cycles. In their GTP form, they interact with specific proteins, the effector proteins. Recent evidence suggests that Rab proteins function in the initial membrane contact connecting the fusing membranes but are not involved in the fusion reaction itself.

VAMP-2, SNAP-25A/B and syntaxin-1 in glutamatergic and GABAergic synapses of the rat cerebellar cortex

PubMed Central

2011-01-01

Background The aim of this study was to assess the distribution of key SNARE proteins in glutamatergic and GABAergic synapses of the adult rat cerebellar cortex using light microscopy immunohistochemical techniques. Analysis was made of co-localizations of vGluT-1 and vGluT-2, vesicular transporters of glutamate and markers of glutamatergic synapses, or GAD, the GABA synthetic enzyme and marker of GABAergic synapses, with VAMP-2, SNAP-25A/B and syntaxin-1. Results The examined SNARE proteins were found to be diffusely expressed in glutamatergic synapses, whereas they were rarely observed in GABAergic synapses. However, among glutamatergic synapses, subpopulations which did not contain VAMP-2, SNAP-25A/B and syntaxin-1 were detected. They included virtually all the synapses established by terminals of climbing fibres (immunoreactive for vGluT-2) and some synapses established by terminals of parallel and mossy fibres (immunoreactive for vGluT-1, and for vGluT-1 and 2, respectively). The only GABA synapses expressing the SNARE proteins studied were the synapses established by axon terminals of basket neurons. Conclusion The present study supplies a detailed morphological description of VAMP-2, SNAP-25A/B and syntaxin-1 in the different types of glutamatergic and GABAergic synapses of the rat cerebellar cortex. The examined SNARE proteins characterize most of glutamatergic synapses and only one type of GABAergic synapses. In the subpopulations of glutamatergic and GABAergic synapses lacking the SNARE protein isoforms examined, alternative mechanisms for regulating trafficking of synaptic vesicles may be hypothesized, possibly mediated by different isoforms or homologous proteins. PMID:22094010

Molecular characterization and functional significance of the Vti family of SNARE proteins in tick salivary glands

PubMed Central

Villarreal, Ashley M.; Adamson, Steven W.; Browning, Rebecca E.; Khem Raj, B.C.; Sajid, Muhammad Sohail; Karim, Shahid

2013-01-01

Exocytosis involves membrane fusion between secretory vesicles and the plasma membrane. The Soluble N-ethylmaleimide-sensitive factor attachment proteins (SNAPs) and their receptor proteins (SNAREs) interact to fuse vesicles with the membrane and trigger the release of their sialosecretome out of the tick salivary gland cells. In this study, we examined the functional significance of the Vti family of SNARE proteins of blood-feeding Amblyomma maculatum and A. americanum. Vti1A and Vti1B have been implicated in multiple functional roles in vesicle transport. QRT-PCR studies demonstrated that the highest transcriptional expression of vti1a and vti1b genes occurs in unfed salivary glands, suggesting that elevated secretory vesicle formation occurs prior to feeding but continues at low rates after blood feeding commences. Vti1A and Vti1B localize to the secretory vesicles in unfed tick salivary glands in immunofluorescence microscopy studies. Knockdown of vti1a and vti1b by RNA interference resulted in a significant decrease in the engorged tick weight compared to the control during prolonged blood-feeding on the host. RNA interference of vti1a or vti1b impaired oviposition and none of the ticks produced eggs masses. Surprisingly, the double knockdown did not produce a strong phenotype and ticks fed normally on the host and produced egg masses, suggesting a compensatory mechanism exists within the secretory system which may have been activated in the double knockdown. These results suggest an important functional role of the Vti family of SNARE proteins in tick blood feeding and ultimately oviposition. Understanding the basic functions of the Vti family of SNARE proteins in salivary glands may lead to better ways to prevent tick attachment and transmission of tick-borne diseases. PMID:23499931

High Cholesterol Obviates a Prolonged Hemifusion Intermediate in Fast SNARE-Mediated Membrane Fusion

PubMed Central

Kreutzberger, Alex J.B.; Kiessling, Volker; Tamm, Lukas K.

2015-01-01

Cholesterol is essential for exocytosis in secretory cells, but the exact molecular mechanism by which it facilitates exocytosis is largely unknown. Distinguishing contributions from the lateral organization and dynamics of membrane proteins to vesicle docking and fusion and the promotion of fusion pores by negative intrinsic spontaneous curvature and other mechanical effects of cholesterol have been elusive. To shed more light on this process, we examined the effect of cholesterol on SNARE-mediated membrane fusion in a single-vesicle assay that is capable of resolving docking and elementary steps of fusion with millisecond time resolution. The effect of cholesterol on fusion pore formation between synaptobrevin-2 (VAMP-2)-containing proteoliposomes and acceptor t-SNARE complex-containing planar supported bilayers was examined using both membrane and content fluorescent markers. This approach revealed that increasing cholesterol in either the t-SNARE or the v-SNARE membrane favors a mechanism of direct fusion pore opening, whereas low cholesterol favors a mechanism leading to a long-lived (>5 s) hemifusion state. The amount of cholesterol in the target membrane had no significant effect on docking of synaptobrevin vesicles. Comparative studies with α-tocopherol (vitamin E) show that the negative intrinsic spontaneous curvature of cholesterol and its presumed promotion of a very short-lived (<50 ms) lipid stalk intermediate is the main factor that favors rapid fusion pore opening at high cholesterol. This study also shows that this single-vesicle fusion assay can distinguish between hemifusion and full fusion with only a single lipid dye, thereby freeing up a fluorescence channel for the simultaneous measurement of another parameter in fast time-resolved fusion assays. PMID:26200867

Progress in understanding the neuronal SNARE function and its regulation.

PubMed

Yoon, T-Y; Shin, Y-K

2009-02-01

Vesicle budding and fusion underlies many essential biochemical deliveries in eukaryotic cells, and its core fusion machinery is thought to be built on one protein family named soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE). Recent technical advances based on site-directed fluorescence labelling and nano-scale detection down to the single-molecule level rapidly unveiled the protein and the lipid intermediates along the fusion pathway as well as the molecular actions of fusion effectors. Here we summarize these new exciting findings in context with a new mechanistic model that reconciles two existing fusion models: the proteinaceous pore model and the hemifusion model. Further, we attempt to locate the points of action for the fusion effectors along the fusion pathway and to delineate the energetic interplay between the SNARE complexes and the fusion effectors.

Planar Supported Membranes with Mobile SNARE Proteins and Quantitative Fluorescence Microscopy Assays to Study Synaptic Vesicle Fusion

PubMed Central

Kiessling, Volker; Liang, Binyong; Kreutzberger, Alex J. B.; Tamm, Lukas K.

2017-01-01

Synaptic vesicle membrane fusion, the process by which neurotransmitter gets released at the presynaptic membrane is mediated by a complex interplay between proteins and lipids. The realization that the lipid bilayer is not just a passive environment where other molecular players like SNARE proteins act, but is itself actively involved in the process, makes the development of biochemical and biophysical assays particularly challenging. We summarize in vitro assays that use planar supported membranes and fluorescence microscopy to address some of the open questions regarding the molecular mechanisms of SNARE-mediated membrane fusion. Most of the assays discussed in this mini-review were developed in our lab over the last 15 years. We emphasize the sample requirements that we found are important for the successful application of these methods. PMID:28360838

Acoustics of Idakkā: An Indian snare drum with definite pitch.

PubMed

Jose, Kevin; Chatterjee, Anindya; Gupta, Anurag

2018-05-01

The vibration of a homogeneous circular membrane backed by two taut strings is shown to yield several harmonic overtones for a wide range of physical and geometric parameters. Such a membrane is present at each end of the barrel of an idakkā, an Indian snare drum well known for its rich musicality. The audio recordings of the musical drum are analyzed and a case is made for the strong sense of pitch associated with the drum. A computationally inexpensive model of the string-membrane interaction is proposed assuming the strings to be without inertia. The interaction essentially entails wrapping/unwrapping of the string around a curve on the deforming membrane unlike the colliding strings in Western snare drums. The range of parameters for which harmonicity is achieved is examined and is found to be conforming with what is used in actual drum playing and construction.

Calcium accelerates SNARE-mediated lipid mixing through modulating α-synuclein membrane interaction.

PubMed

Zhang, Zeting; Jiang, Xin; Xu, Danrui; Zheng, Wenwen; Liu, Maili; Li, Conggang

2018-04-04

α-Synuclein is involved in Parkinson's disease, and its interaction with cell membrane is vital to its pathological and physiological functions. We have shown that Ca 2+ can regulate α-synuclein membrane interaction, but the physiological role of Ca 2+ in modulating α-synuclein membrane interaction is still unexplored. Based on the previous findings that α-synuclein inhibits membrane fusion and its inhibitory effect is highly related to its membrane binding, here we employed solution state Nuclear Magnetic Resonance (NMR) spectroscopy and the ensemble fluorescence fusion assay to show that Ca 2+ can modulate the inhibitory effect of α-synuclein on SNARE-mediated membrane fusion through disrupting α-synuclein membrane interaction, resulting in acceleration of SNARE-mediated membrane fusion. These results suggest a modulatory effect of Ca 2+ on membrane mediated normal function of α-synuclein, which of importance for the study of the Parkinson's disease. Copyright © 2018 Elsevier B.V. All rights reserved.

Endoscopic removal of a tablespoon lodged within the duodenum

PubMed Central

Watanabe, Takashi; Aoyagi, Kunihiko; Tomioka, Yoshitaka; Ishibashi, Hideki; Sakisaka, Shotaro

2015-01-01

Here we report the case of a 34-year-old man who underwent endoscopic removal of a tablespoon from the stomach that was lodged within the duodenum. Removal required the use of a two-channel upper endoscope and polypectomy snares. Using the double-snare technique, the spoon was grasped at the proximal and distal parts of the handle. The double-snare was first pulled unsuccessfully and then pulled with simultaneous manual abdominal compression of the bulbus from the body surface. Compression was gently applied towards the stomach. As a result, the head of the spoon prolapsed from the bulbus, and was easily retracted from the stomach without any complications. In cases of foreign body lodging within the duodenum, the manual abdominal compression technique may help clinicians pull out the object and avoid surgery. The usefulness of manual compression is dependent on the foreign body’s sharpness and the location. PMID:25945026

Left Atrial Appendage Closure with Amplatzer Cardiac Plug in Nonvalvular Atrial Fibrillation: Safety and Long-Term Outcome.

PubMed

Costa, Marcio José Montenegro da; Ferreira, Esmeralci; Quintella, Edgard Freitas; Amorim, Bernardo; Fuchs, Alexandre; Zajdenverg, Ricardo; Sabino, Hugo; Albuquerque, Denilson Campos de

2017-12-01

Atrial fibrillation (AF) is a cardiac arrhythmia with high risk for thromboembolic events, specially stroke. To assess the safety of left atrial appendage closure (LAAC) with the Amplatzer Cardiac Plug for the prevention of thromboembolic events in patients with nonvalvular AF. This study included 15 patients with nonvalvular AF referred for LAAC, 6 older than 75 years (mean age, 69.4 ± 9.3 years; 60% of the male sex). The mean CHADS2 score was 3.4 ± 0.1, and mean CHA2DS2VASc , 4.8 ± 1.8, evidencing a high risk for thromboembolic events. All patients had a HAS-BLED score > 3 (mean, 4.5 ± 1.2) with a high risk for major bleeding within 1 year. The device was successfully implanted in all patients, with correct positioning in the first attempt in most of them (n = 11; 73.3%). There was no periprocedural complication, such as device migration, pericardial tamponade, vascular complications and major bleeding. All patients had an uneventful in-hospital course, being discharged in 2 days. The echocardiographic assessments at 6 and 12 months showed neither device migration, nor thrombus formation, nor peridevice leak. On clinical assessment at 12 months, no patient had thromboembolic events or bleeding related to the device or risk factors. In this small series, LAAC with Amplatzer Cardiac Plug proved to be safe, with high procedural success rate and favorable outcome at the 12-month follow-up. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0).

UNC-18 and Tomosyn Antagonistically Control Synaptic Vesicle Priming Downstream of UNC-13 in Caenorhabditis elegans

PubMed Central

Park, Seungmee; Bin, Na-Ryum; Wong, Raymond; Sitarska, Ewa; Sugita, Kyoko; Ma, Ke; Algouneh, Arash; Turlova, Ekaterina; Wang, Siyan; Siriya, Pranay; Kalia, Lorraine; Feng, Zhong-Ping; Monnier, Philippe P.; Zhen, Mei; Gao, Shangbang

2017-01-01

Munc18-1/UNC-18 is believed to prime SNARE-mediated membrane fusion, yet the underlying mechanisms remain enigmatic. Here, we examine how potential gain-of-function mutations of Munc18-1/UNC-18 affect locomotory behavior and synaptic transmission, and how Munc18-1-mediated priming is related to Munc13-1/UNC-13 and Tomosyn/TOM-1, positive and negative SNARE regulators, respectively. We show that a Munc18-1(P335A)/UNC-18(P334A) mutation leads to significantly increased locomotory activity and acetylcholine release in Caenorhabditis elegans, as well as enhanced synaptic neurotransmission in cultured mammalian neurons. Importantly, similar to tom-1 null mutants, unc-18(P334A) mutants partially bypass the requirement of UNC-13. Moreover, unc-18(P334A) and tom-1 null mutations confer a strong synergy in suppressing the phenotypes of unc-13 mutants. Through biochemical experiments, we demonstrate that Munc18-1(P335A) exhibits enhanced activity in SNARE complex formation as well as in binding to the preformed SNARE complex, and partially bypasses the Munc13-1 requirement in liposome fusion assays. Our results indicate that Munc18-1/UNC-18 primes vesicle fusion downstream of Munc13-1/UNC-13 by templating SNARE complex assembly and acts antagonistically with Tomosyn/TOM-1. SIGNIFICANCE STATEMENT At presynaptic sites, SNARE-mediated membrane fusion is tightly regulated by several key proteins including Munc18/UNC-18, Munc13/UNC-13, and Tomosyn/TOM-1. However, how these proteins interact with each other to achieve the precise regulation of neurotransmitter release remains largely unclear. Using Caenorhabditis elegans as an in vivo model, we found that a gain-of-function mutant of UNC-18 increases locomotory activity and synaptic acetylcholine release, that it partially bypasses the requirement of UNC-13 for release, and that this bypass is synergistically augmented by the lack of TOM-1. We also elucidated the biochemical basis for the gain-of-function caused by this mutation. Thus, our study provides novel mechanistic insights into how Munc18/UNC-18 primes synaptic vesicle release and how this protein interacts functionally with Munc13/UNC-13 and Tomosyn/TOM-1. PMID:28821673

Hrs regulates early endosome fusion by inhibiting formation of an endosomal SNARE complex

PubMed Central

Sun, Wei; Yan, Qing; Vida, Thomas A.; Bean, Andrew J.

2003-01-01

Movement through the endocytic pathway occurs principally via a series of membrane fusion and fission reactions that allow sorting of molecules to be recycled from those to be degraded. Endosome fusion is dependent on SNARE proteins, although the nature of the proteins involved and their regulation has not been fully elucidated. We found that the endosome-associated hepatocyte responsive serum phosphoprotein (Hrs) inhibited the homotypic fusion of early endosomes. A region of Hrs predicted to form a coiled coil required for binding the Q-SNARE, SNAP-25, mimicked the inhibition of endosome fusion produced by full-length Hrs, and was sufficient for endosome binding. SNAP-25, syntaxin 13, and VAMP2 were bound from rat brain membranes to the Hrs coiled-coil domain. Syntaxin 13 inhibited early endosomal fusion and botulinum toxin/E inhibition of early endosomal fusion was reversed by addition of SNAP-25(150–206), confirming a role for syntaxin 13, and establishing a role for SNAP-25 in endosomal fusion. Hrs inhibited formation of the syntaxin 13–SNAP-25–VAMP2 complex by displacing VAMP2 from the complex. These data suggest that SNAP-25 is a receptor for Hrs on early endosomal membranes and that the binding of Hrs to SNAP-25 on endosomal membranes inhibits formation of a SNARE complex required for homotypic endosome fusion. PMID:12847087

An electrode to record the mouse cornea electroretinogram.

PubMed

Goto, Y

The mouse has become a popular model for the study of retinal degeneration, but an electrode suitable for recording electroretinograms from the mouse cornea is not available commercially. I developed a simple electrode suitable for the relatively small mouse eye by attaching a thin stainless-steel wire through the barrel of a 1-cc syringe. The end of the wire is formed into a coil by wrapping it around a 0.5- or 1.0-mm pin. The syringe barrel serves as a convenient way to hold the electrode in a goose-neck holder. This electrode has been used successfully to obtain electroretinograms from hundreds of mice as young as 14 days.

Transition from strike-slip faulting to oblique subduction: active tectonics at the Puysegur Margin, South New Zealand

NASA Astrophysics Data System (ADS)

Lamarche, Geoffroy; Lebrun, Jean-Frédéric

2000-01-01

South of New Zealand the Pacific-Australia (PAC-AUS) plate boundary runs along the intracontinental Alpine Fault, the Puysegur subduction front and the intraoceanic Puysegur Fault. The Puysegur Fault is located along Puysegur Ridge, which terminates at ca. 47°S against the continental Puysegur Bank in a complex zone of deformation called the Snares Zone. At Puysegur Trench, the Australian Plate subducts beneath Puysegur Bank and the Fiordland Massif. East of Fiordland and Puysegur Bank, the Moonlight Fault System (MFS) represents the Eocene strike-slip plate boundary. Interpretation of seafloor morphology and seismic reflection profiles acquired over Puysegur Bank and the Snares Zone allows study of the transition from intraoceanic strike-slip faulting along the Puysegur Ridge to oblique subduction at the Puysegur Trench and to better understand the genetic link between the Puysegur Fault and the MFS. Seafloor morphology is interpreted from a bathymetric dataset compiled from swath bathymetry data acquired during the 1993 Geodynz survey, and single beam echo soundings acquired by the NZ Royal Navy. The Snares Zone is the key transition zone from strike-slip faulting to subduction. It divides into three sectors, namely East, NW and SW sectors. A conspicuous 3600 m-deep trough (the Snares Trough) separates the NW and East sectors. The East sector is characterised by the NE termination of Puysegur Ridge into right-stepping en echelon ridges that accommodate a change of strike from the Puysegur Fault to the MFS. Between 48°S and 47°S, in the NW sector and the Snares Trough, a series of transpressional faults splay northwards from the Puysegur Fault. Between 49°50'S and 48°S, thrusts develop progressively at Puysegur Trench into a decollement. North of 48°S the Snares Trough develops between two splays of the Puysegur Fault, indicating superficial extension associated with the subsidence of Puysegur Ridge. Seismic reflection profiles and bathymetric maps show a series of transpressional faults that splay northwards across the Snares Fault, and terminate at the top of the Puysegur trench slope. Between ca. 48°S and 46°30'S, the relative plate motion appears to be distributed over the Puysegur subduction zone and the strike-slip faults located on the edge of the upper plate. Conversely, north of ca. 46°S, a lack of active strike-slip faulting along the MFS and across most of Puysegur Bank indicates that the subduction in the northern part of Puysegur Trench accounts for most of the oblique convergence. Hence, active transpression in the Snares fault zone indicates that the relative PAC-AUS plate motion is transferred from strike-slip faulting along the Puysegur Fault to subduction at Puysegur Trench. The progressive transition from thrusts at Puysegur Trench and strike-slip faulting at the Puysegur Fault to oblique subduction at Puysegur Trench suggests that the subduction interface progressively developed from a western shallow splay of the Puysegur Fault. It implies that the transfer fault links the subduction interface at depth. A tectonic sliver is identified between Puysegur Trench and the Puysegur Fault. Its northwards motion relative to the Pacific Plate implies that is might collide with Puysegur Bank.

Synaptotagmin C2B Domain Regulates Ca2+-triggered Fusion in Vitro

PubMed Central

Gaffaney, Jon D.; Dunning, F. Mark; Wang, Zhao; Hui, Enfu; Chapman, Edwin R.

2008-01-01

Synaptotagmin (syt) 1 is localized to synaptic vesicles, binds Ca2+, and regulates neuronal exocytosis. Syt 1 harbors two Ca2+-binding motifs referred to as C2A and C2B. In this study we examine the function of the isolated C2 domains of Syt 1 using a reconstituted, SNARE (soluble N-ethylmaleimide-sensitive factor attachment receptor)-mediated, fusion assay. We report that inclusion of phosphatidylethanolamine into reconstituted SNARE vesicles enabled isolated C2B, but not C2A, to regulate Ca2+-triggered fusion. The isolated C2B domain had a 6-fold lower EC for Ca2+ 50-activated fusion than the intact cytosolic domain of Syt 1 (C2AB). Phosphatidylethanolamine increased both the rate and efficiency of C2AB- and C2B-regulated fusion without affecting their abilities to bind membrane-embedded syntaxin-SNAP-25 (t-SNARE) complexes. At equimolar concentrations, the isolated C2A domain was an effective inhibitor of C2B-, but not C2AB-regulated fusion; hence, C2A has markedly different effects in the fusion assay depending on whether it is tethered to C2B. Finally, scanning alanine mutagenesis of C2AB revealed four distinct groups of mutations within the C2B domain that play roles in the regulation of SNARE-mediated fusion. Surprisingly, substitution of Arg-398 with alanine, which lies on the opposite end of C2B from the Ca2+/membrane-binding loops, decreases C2AB t-SNARE binding and Ca2+-triggered fusion in vitro without affecting Ca2+-triggered interactions with phosphatidylserine or vesicle aggregation. In addition, some mutations uncouple the clamping and stimulatory functions of syt 1, suggesting that these two activities are mediated by distinct structural determinants in C2B. PMID:18784080

Equine grass sickness, but not botulism, causes autonomic and enteric neurodegeneration and increases soluble N-ethylmaleimide-sensitive factor attachment receptor protein expression within neuronal perikarya.

PubMed

McGorum, B C; Scholes, S; Milne, E M; Eaton, S L; Wishart, T M; Poxton, I R; Moss, S; Wernery, U; Davey, T; Harris, J B; Pirie, R S

2016-11-01

Equine grass sickness (EGS) is of unknown aetiology. Despite some evidence suggesting that it represents a toxico-infection with Clostridium botulinum types C and/or D, the effect of EGS on the functional targets of botulinum neurotoxins, namely the soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins, is unknown. Further, while it is commonly stated that, unlike EGS, equine botulism is not associated with autonomic and enteric neurodegeneration, this has not been definitively assessed. To determine: 1) whether botulism causes autonomic and enteric neurodegeneration; and 2) the effect of EGS on the expression of SNARE proteins within cranial cervical ganglion (CCG) and enteric neuronal perikarya. Descriptive study. Light microscopy was used to compare the morphology of neurons in haematoxylin-eosin stained sections of CCG and ileum from 6 EGS horses, 5 botulism horses and 6 control horses. Immunohistochemistry was used to compare the expression of synaptosomal-associated protein-25, synaptobrevin (Syb) and syntaxin within CCG neurons, and of Syb in enteric neurons, from horses with EGS, horses with botulism and control horses. The concentrations of these SNARE proteins in extracts of CCG from EGS and control horses were compared using quantitative fluorescent western blotting. EGS, but not botulism, was associated with autonomic and enteric neurodegeneration and with increased immunoreactivity for SNARE proteins within neuronal perikarya. Quantitative fluorescent western blotting confirmed increased concentrations of synaptosomal-associated protein-25, Syb and syntaxin within CCG extracts from EGS vs. control horses, with the increases in the latter 2 proteins being statistically significant. The occurrence of autonomic and enteric neurodegeneration, and increased expression of SNARE proteins within neuronal perikarya, in EGS but not botulism, suggests that EGS may not be caused by botulinum neurotoxins. Further investigation of the aetiology of EGS is therefore warranted. © 2015 EVJ Ltd.

Density drives polyandry and relatedness influences paternal success in the Pacific gooseneck barnacle, Pollicipes elegans.

PubMed

Plough, Louis V; Moran, Amy; Marko, Peter

2014-04-16

Polyandry is a common mating strategy in animals, increasing female fitness through direct (material) and indirect (genetic) benefits. Most theories about the benefits of polyandry come from studies of terrestrial animals, which have relatively complex mating systems and behaviors; less is known about the potential benefits of polyandry in sessile marine animals, for which potential mates may be scarce and females have less control over pre-copulatory mate choice. Here, we used microsatellite markers to examine multiple paternity in natural aggregations of the Pacific gooseneck barnacle Pollicipes elegans, testing the effect of density on paternity and mate relatedness on male reproductive success. We found that multiple paternity was very common (79% of broods), with up to five fathers contributing to a brood, though power was relatively low to detect more than four fathers. Density had a significant and positive linear effect on the number of fathers siring a brood, though this relationship leveled off at high numbers of fathers, which may reflect a lack of power and/or an upper limit to polyandry in this species. Significant skew in male reproductive contribution in multiply-sired broods was observed and we found a positive and significant relationship between the proportion of offspring sired and the genetic similarity between mates, suggesting that genetic compatibility may influence reproductive success in this species. To our knowledge, this is the first study to show high levels of multiple paternity in a barnacle, and overall, patterns of paternity in P. elegans appear to be driven primarily by mate availability. Evidence of paternity bias for males with higher relatedness suggests some form of post-copulatory sexual selection is taking place, but more work is needed to determine whether it operates during or post-fertilization. Overall, our results suggest that while polyandry in P. elegans is driven by mate availability, it may also provide a mechanism for females to ensure fertilization by compatible gametes and increase reproductive success in this sessile species.

Structural Basis for the Interaction of the Golgi-Associated Retrograde Protein (GARP) Complex with the t-SNARE Syntaxin 6

PubMed Central

Abascal-Palacios, Guillermo; Schindler, Christina; Rojas, Adriana L; Bonifacino, Juan S.; Hierro, Aitor

2016-01-01

Summary The Golgi-Associated Retrograde Protein (GARP) is a tethering complex involved in the fusion of endosome-derived transport vesicles to the trans-Golgi network through interaction with components of the Syntaxin 6/Syntaxin 16/Vti1a/VAMP4 SNARE complex. The mechanisms by which GARP and other tethering factors engage the SNARE fusion machinery are poorly understood. Herein we report the structural basis for the interaction of the human Ang2 subunit of GARP with Syntaxin 6 and the closely related Syntaxin 10. The crystal structure of Syntaxin 6 Habc domain in complex with a peptide from the N terminus of Ang2 shows a novel binding mode in which a di-tyrosine motif of Ang2 interacts with a highly conserved groove in Syntaxin 6. Structure-based mutational analyses validate the crystal structure and support the phylogenetic conservation of this interaction. The same binding determinants are found in other tethering proteins and syntaxins, suggesting a general interaction mechanism. PMID:23932592

Expression of the SNARE Protein SNAP-23 Is Essential for Cell Survival

PubMed Central

Kaul, Sunil; Mittal, Sharad K.; Feigenbaum, Lionel; Kruhlak, Michael J.; Roche, Paul A.

2015-01-01

Members of the SNARE-family of proteins are known to be key regulators of the membrane-membrane fusion events required for intracellular membrane traffic. The ubiquitously expressed SNARE protein SNAP-23 regulates a wide variety of exocytosis events and is essential for mouse development. Germline deletion of SNAP-23 results in early embryonic lethality in mice, and for this reason we now describe mice and cell lines in which SNAP-23 can be conditionally-deleted using Cre-lox technology. Deletion of SNAP-23 in CD19-Cre expressing mice prevents B lymphocyte development and deletion of SNAP-23 using a variety of T lymphocyte-specific Cre mice prevents T lymphocyte development. Acute depletion of SNAP-23 in mouse fibroblasts leads to rapid apoptotic cell death. These data highlight the importance of SNAP-23 for cell survival and describe a mouse in which specific cell types can be eliminated by expression of tissue-specific Cre-recombinase. PMID:25706117

Fusion of single proteoliposomes with planar, cushioned bilayers in microfluidic flow cells

PubMed Central

Karatekin, Erdem; Rothman, James E.

2013-01-01

Many biological processes rely on membrane fusion, therefore assays to study its mechanisms are necessary. Here we report an assay with sensitivity to single-vesicle, even to single-molecule events using fluorescently labeled vesicle-associated v-SNARE liposomes and target-membrane-associated t-SNARE-reconstituted planar, supported bilayers (SBLs). Docking and fusion events can be detected using conventional far-field epifluorescence or total internal reflection fluorsecence microscopy. Unlike most previous attempts, fusion here is dependent on SNAP25, one of the t-SNARE subunits that is required for fusion in vivo. The success of the assay is due to the use of (i) bilayers covered with a thin layer of poly(ethylene glycol) to control bilayer-bilayer and bilayer-substrate interactions, (ii) microfluidic flow channels which presents many advantages such as the removal of non-specifically bound liposomes by flow. The protocol takes 6–8 days to complete. Analysis can take up to two weeks. PMID:22517259

Architecture of the Synaptotagmin-SNARE Machinery for Neuronal Exocytosis

PubMed Central

Zhou, Qiangjun; Lai, Ying; Bacaj, Taulant; Zhao, Minglei; Lyubimov, Artem Y.; Uervirojnangkoorn, Monarin; Zeldin, Oliver B.; Brewster, Aaron S.; Sauter, Nicholas K.; Cohen, Aina E.; Soltis, S. Michael; Alonso-Mori, Roberto; Chollet, Matthieu; Lemke, Henrik T.; Pfuetzner, Richard A.; Choi, Ucheor B.; Weis, William I.; Diao, Jiajie; Südhof, Thomas C.; Brunger, Axel T.

2015-01-01

Summary Synaptotagmin-1 and neuronal SNARE proteins play key roles in evoked synchronous neurotransmitter release. However, it is unknown how they cooperate to trigger synaptic vesicle fusion. Here we report atomic-resolution crystal structures of Ca2+- and Mg2+-bound complexes between synaptotagmin-1 and the neuronal SNARE complex, one of which was determined with diffraction data from an X-ray free electron laser, leading to an atomic-resolution structure with accurate rotamer assignments for many sidechains. The structures revealed several interfaces, including a large, specific, Ca2+-independent, and conserved interface. Tests of this interface by mutagenesis suggest that it is essential for Ca2+-triggered neurotransmitter release in neuronal synapses and for Ca2+-triggered vesicle fusion in a reconstituted system. We propose that this interface forms prior to Ca2+-triggering, and moves en bloc as Ca2+ influx promotes the interactions between synaptotagmin-1 and the plasma membrane, and consequently remodels the membrane to promote fusion, possibly in conjunction with other interfaces. PMID:26280336

Rescue endoscopic bleeding control for nonvariceal upper gastrointestinal hemorrhage using clipping and detachable snaring.

PubMed

Lee, J H; Kim, B K; Seol, D C; Byun, S J; Park, K H; Sung, I K; Park, H S; Shim, C S

2013-06-01

Nonvariceal upper gastrointestinal (UGI) bleeding recurs after appropriate endoscopic therapy in 10 % - 15 % of cases. The mortality rate can be as high as 25 % when bleeding recurs, but there is no consensus about the best modality for endoscopic re-treatment. The aim of this study was to evaluate clipping and detachable snaring (CDS) for rescue endoscopic control of nonvariceal UGI hemorrhage. We report a case series of seven patients from a Korean tertiary center who underwent endoscopic hemostasis using the combined method of detachable snares with hemoclips. The success rate of endoscopic hemostasis with CDS was 86 %: six of the seven patients who had experienced primary endoscopic treatment failure or recurrent bleeding after endoscopic hemostasis were treated successfully. In conclusion, rescue endoscopic bleeding control by means of CDS is an option for controlling nonvariceal UGI bleeding when no other method of endoscopic treatment for recurrent bleeding and primary hemostatic failure is possible. © Georg Thieme Verlag KG Stuttgart · New York.

CVAK104 is a Novel Regulator of Clathrin-mediated SNARE Sorting

PubMed Central

Borner, Georg H H; Rana, Amer A; Forster, Rebecca; Harbour, Michael; Smith, James C; Robinson, Margaret S

2007-01-01

Clathrin-coated vesicles (CCVs) mediate transport between the plasma membrane, endosomes and the trans Golgi network. Using comparative proteomics, we have identified coated-vesicle-associated kinase of 104 kDa (CVAK104) as a candidate accessory protein for CCV-mediated trafficking. Here, we demonstrate that the protein colocalizes with clathrin and adaptor protein-1 (AP-1), and that it is associated with a transferrin-positive endosomal compartment. Consistent with these observations, clathrin as well as the cargo adaptors AP-1 and epsinR can be coimmunoprecipitated with CVAK104. Small interfering RNA (siRNA) knockdown of CVAK104 in HeLa cells results in selective loss of the SNARE proteins syntaxin 8 and vti1b from CCVs. Morpholino-mediated knockdown of CVAK104 in Xenopus tropicalis causes severe developmental defects, including a bent body axis and ventral oedema. Thus, CVAK104 is an evolutionarily conserved protein involved in SNARE sorting that is essential for normal embryonic development. PMID:17587408

Architecture of the synaptotagmin–SNARE machinery for neuronal exocytosis

DOE PAGES

Zhou, Qiangjun; Lai, Ying; Bacaj, Taulant; ...

2015-08-17

Synaptotagmin-1 and neuronal SNARE proteins have central roles in evoked synchronous neurotransmitter release; however, it is unknown how they cooperate to trigger synaptic vesicle fusion. We report atomic-resolution crystal structures of Ca 2+- and Mg 2+-bound complexes between synaptotagmin-1 and the neuronal SNARE complex, one of which was determined with diffraction data from an X-ray free-electron laser, leading to an atomic-resolution structure with accurate rotamer assignments for many side chains. The structures reveal several interfaces, including a large, specific, Ca 2+-independent and conserved interface. Tests of this interface by mutagenesis suggest that it is essential for Ca 2+-triggered neurotransmitter releasemore » in mouse hippocampal neuronal synapses and for Ca 2+-triggered vesicle fusion in a reconstituted system. Lastly, we propose that this interface forms before Ca 2+ triggering, moves en bloc as Ca 2+ influx promotes the interactions between synaptotagmin-1 and the plasma membrane, and consequently remodels the membrane to promote fusion, possibly in conjunction with other interfaces.« less

Persistence of pulmonary arteriovenous malformations after successful embolotherapy with Amplatzer vascular plug: long-term results

PubMed Central

Abdel-Aal, Ahmed Kamel; Ibrahim, Rafik Mohamed; Moustafa, Amr Soliman; Hamed, Maysoon Farouk; Saddekni, Souheil

2016-01-01

PURPOSE We aimed to evaluate the frequency of persistence and complication rates of pulmonary arteriovenous malformations (PAVMs) treated with Amplatzer vascular plug (AVP) or Amplatzer vascular plug type 2 (AVP2). METHODS We retrospectively reviewed a total of 22 patients with 54 PAVMs between June 2004 and June 2014. We included 12 patients with 35 PAVMs who received percutaneous embolization using AVP or AVP2 only without the use of any other embolic devices. The mean follow-up was 54±24.3 months (range, 31–97 months). The primary end-points of the study were the efficacy of embolotherapy, the increase in oxygen saturation, and the persistence of PAVM on follow-up. Secondary end point was the incidence of complications. RESULTS The study included 10 female and two male patients with a mean age of 50.2±13.7 years (range, 21–66 years). All PAVMs had a simple angioarchitecture. The technical success of the procedure for PAVM occlusion was 100%. There was a significant increase in the oxygen saturation following embolotherapy (P < 0.0001). Follow-up computed tomography angiography revealed successful treatment in 34 PAVMs (97%) and failed treatment in one PAVM (3%). Twenty-three aneurysmal sacs (67%) showed complete disappearance. The failed treatment was due to persistence of PAVM caused by subsequent development of systemic reperfusion, which did not require further intervention. There were two minor complications but no major complications were encountered. CONCLUSION Embolotherapy of PAVMs using AVP or AVP2 devices is safe and effective, with high technical success rate, low persistence and complication rates, and with excellent long-term results. PMID:27244759

Long-term outcome after percutaneous closure of persistent left superior caval vein draining into the left atrium: a contrast-enhanced CT study.

PubMed

Marini, Davide; Castagno, Matteo; Millesimo, Michele; Ferroni, Francesca; Ferraro, Gaetana; Pace Napoleone, Carlo; Agnoletti, Gabriella

2017-10-01

Data regarding long-term outcome after percutaneous closure of left superior caval vein draining into the left atrium are lacking. The aim of the present study was to report the long-term follow-up by using contrast-enhanced CT. In all, three patients underwent percutaneous closure of left superior caval vein draining into the left atrium between 2005 and 2015. All of them were evaluated clinically and underwent contrast-enhanced CT. In one patient, the Amplatzer® Septal Occluder was used. In two patients, the Amplatzer® Vascular Plug type-1 was preferred: the device size/LSVC diameter ratio was 1.7 in the child and 1.2 in the adult. There were no early-onset or long-term onset complications. CT was performed 1, 2, and 10 years after the procedure, respectively. Complete occlusion of the vessel was documented in all. After 10 years since the procedure, CT revealed a persistent trivial residual shunt through the accessory hemiazygos vein in one patient, in whom the device was implanted above its drainage into the left superior caval vein. When an Amplatzer® Vascular Plug type-1 is oversized compared with the venous vessel diameter, it immediately assumes a dog-bone shape that disappears early to regain its shape memory and nominal size. Percutaneous occlusion of left superior caval vein draining into the left atrium has excellent early and long-term outcomes. The optimal implantation of the device is below the drainage of the accessory hemiazygos vein, when present. The device might be oversized compared with the left superior caval vein diameter according to the age of the patient.

Long-Term Results of Transcatheter Closure of Patent Ductus Arteriosus in Infants Using Amplatzer Duct Occluder

PubMed Central

Behjati-Ardakani, Mostafa; Behjati-Ardakani, Mohammad-Amin; Hosseini, Seyed-Habibolla; Noori, Noormohammad

2013-01-01

Objective Patent ductus arteriosus (PDA) is one of the most frequently seen congenital heart diseases. Its closure is recommended because of the risk of infective endocardis, as well as morbidity and mortality in the long. The aim of this study was to assess the long term results of the transcatheter closure of PDA in infants using amplatzer duct occlude (ADO). Methods From May 2004 to September 2011, forty eight infants underwent transcatheter closure of PDA. A lateral or right anterior oblique view aortogram was done to locate PDA and to measure its size. Before discharge, repeat aortogram was performed to evaluate eventual residual shunt and to confirm the appropriate deployment of the ADO. Follow up evaluations were done with transthoracic echocardiography at discharge, 1 month, 6 months, 12 months and yearly thereafter. Findings The mean age of patients at procedure was 9.18±2.32 (range 3 to 12) months, mean weight 6.73±1.16 (range 4.5 to 10.1) kg. The PDA occluded completely in 20 out of the 48 patients. Twenty four patients had trivial or mild shunt and two patients had moderate residual shunt which disappeared in one patient within 24 hours and other patient with moderate shunt in 1 month. One patient (age 8 months) had mild LPA stenosis. The device emobolization occurred in two patients, immediately after the procedure in one and during night in the other patient Conclusion The long term results suggested that transcatheter closure of PDA using Amplatzer duct occluder is a safe and effective treatment in infants less than 1 year of age with minimal complications. PMID:24427494

Closure of tubular patent ductus arteriosus with the Amplatzer Vascular Plug IV: feasibility and safety.

PubMed

Baruteau, Alban-Elouen; Lambert, Virginie; Riou, Jean-Yves; Angel, Claude-Yves; Belli, Emre; Petit, Jérôme

2015-01-01

Closure of tubular patent ductus arteriosus remains a challenging procedure. Anecdotal use of Amplatzer Vascular Plug IV for tubular ductus closure has been reported but feasibility and safety in a consecutive patients' series remain unknown. We performed a monocenter prospective study at the Marie Lannelongue Hospital in Paris, France. From 2009 to 2014, a total of 47 patients (39 infants, 3 children, and 5 adults) underwent ductus closure with the Plug IV. Ductus morphology was a type E in 34 (72.3%) patients and a type C in 13 (27.7%) patients. Ductus closure occurred in 39 (83.0%) infants at a median age of seven months (range: 3-23 months) and a median weight of 6.9 kg (range: 4.1-17.0 kg). A past history of prematurity and very low birth weight was found in 33 (70.2%) of them. Twelve (25.5%) patients had pulmonary hypertension. Mean Plug IV diameter was 1.9 ± 0.1 mm larger than the mean maximal ductus diameter. Early complete closure of the ductus was obtained in all patients. Early migration of an undersized Plug IV occurred in one (2.1%) patient and was suitable for percutaneous device retrieval. After a mean follow-up of 3.4 ± 1.4 years, all patients are alive and asymptomatic, no late complication occurred. Transcatheter closure of tubular ductus with the Amplatzer Vascular Plug IV can be safe and effective, with a 100% early occlusion rate. This device, suitable for a 4F sheath, is a new alternative for tubular ductus closure in low-body-weight infants. © The Author(s) 2014.

Percutaneous closure of hypertensive ductus arteriosus.

PubMed

Zabal, Carlos; García-Montes, José Antonio; Buendía-Hernández, Alfonso; Calderón-Colmenero, Juan; Patiño-Bahena, Emilia; Juanico-Enriquez, Antonio; Attie, Fause

2010-04-01

The Amplatzer duct occluder (ADO) has been used with success to close large patent ductus arteriosus (PDA), but some problems exist especially with hypertensive PDAs, such as incomplete closure, haemolysis, left pulmonary artery stenosis, obstruction of the descending aorta and progressive pulmonary vascular disease. We analysed a group of 168 patients with isolated PDA and pulmonary artery systolic pressure (PSAP) > or =50 mm Hg. Mean age was 10.3 +/- 14.3 years (median 3.9), PDA diameter was 6.4 +/- 2.9 mm (median 5.9), PASP was 63.5 +/- 16.2 mm Hg (median 60), Qp/Qs was 2.7 +/- 1.2 (median 2.5), total pulmonary resistance index (PRI) was 3.69 +/- 2.15 (median 3.35) and vascular PRI was 2.73 +/- 1.72 (median 2.37). We used ADOs in 145 (86.3%) cases, Amplatzer muscular ventricular septal defect occluders (AMVSDO) in 18 (10.7%), Amplatzer septal occluders (ASO) in three (1.8%) and the Gianturco-Grifka device in two (1.2%) cases. Device diameter was 106.3% +/- 51% higher than PDA diameter. PASP decreased after occlusion to 42.5 +/- 13.3 mm Hg (p<0.00001). Immediately after closure, no or trivial shunt was present in 123 (74.5%) cases. Immediate complications were device embolisation in five (3%) cases and descending aortic obstruction in one case. The overall success rate was 98.2%. Follow-up in 145 (86.3%) cases for 37.1 +/- 24 months (median 34.1) showed further decrease of the PASP to 30.1 +/- 7.7 mm Hg (p<0.0001). Percutaneous treatment of hypertensive PDA is safe and effective. ADO works well for most cases, but sometimes other devices (MVSDO or ASO) have to be used. When cases are selected adequately, pulmonary pressures decrease immediately and continue to fall with time.

SNAP-23 regulates phagosome formation and maturation in macrophages

PubMed Central

Sakurai, Chiye; Hashimoto, Hitoshi; Nakanishi, Hideki; Arai, Seisuke; Wada, Yoh; Sun-Wada, Ge-Hong; Wada, Ikuo; Hatsuzawa, Kiyotaka

2012-01-01

Synaptosomal associated protein of 23 kDa (SNAP-23), a plasma membrane–localized soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE), has been implicated in phagocytosis by macrophages. For elucidation of its precise role in this process, a macrophage line overexpressing monomeric Venus–tagged SNAP-23 was established. These cells showed enhanced Fc receptor–mediated phagocytosis. Detailed analyses of each process of phagocytosis revealed a marked increase in the production of reactive oxygen species within phagosomes. Also, enhanced accumulation of a lysotropic dye, as well as augmented quenching of a pH-sensitive fluorophore were observed. Analyses of isolated phagosomes indicated the critical role of SNAP-23 in the functional recruitment of the NADPH oxidase complex and vacuolar-type H+-ATPase to phagosomes. The data from the overexpression experiments were confirmed by SNAP-23 knockdown, which demonstrated a significant delay in phagosome maturation and a reduction in uptake activity. Finally, for analyzing whether phagosomal SNAP-23 entails a structural change in the protein, an intramolecular Förster resonance energy transfer (FRET) probe was constructed, in which the distance within a TagGFP2-TagRFP was altered upon close approximation of the N-termini of its two SNARE motifs. FRET efficiency on phagosomes was markedly enhanced only when VAMP7, a lysosomal SNARE, was coexpressed. Taken together, our results strongly suggest the involvement of SNAP-23 in both phagosome formation and maturation in macrophages, presumably by mediating SNARE-based membrane traffic. PMID:23087210

Therapeutic use of botulinum toxin in migraine: mechanisms of action

PubMed Central

Ramachandran, Roshni; Yaksh, Tony L

2014-01-01

Migraine pain represents sensations arising from the activation of trigeminal afferents, which innervate the meningeal vasculature and project to the trigeminal nucleus caudalis (TNC). Pain secondary to meningeal input is referred to extracranial regions innervated by somatic afferents that project to homologous regions in the TNC. Such viscerosomatic convergence accounts for referral of migraine pain arising from meningeal afferents to particular extracranial dermatomes. Botulinum toxins (BoNTs) delivered into extracranial dermatomes are effective in and approved for treating chronic migraine pain. Aside from their well-described effect upon motor endplates, BoNTs are also taken up in local afferent nerve terminals where they cleave soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, and prevent local terminal release. However, a local extracranial effect of BoNT cannot account for allthe effects of BoNT upon migraine. We now know that peripherally delivered BoNTs are taken up in sensory afferents and transported to cleave SNARE proteins in the ganglion and TNC, prevent evoked afferent release and downstream activation. Such effects upon somatic input (as from the face) likewise would not alone account for block of input from converging meningeal afferents. This current work suggests that BoNTs may undergo transcytosis to cleave SNAREs in second-order neurons or in adjacent afferent terminals. Finally, while SNAREs mediate exocytotic release, they are also involved in transport of channels and receptors involved in facilitated pain states. The role of such post-synaptic effects of BoNT action in migraine remains to be determined. PMID:24819339

Rectal temperatures of immobilized, snare-trapped black bears in Great Dismal Swamp.

PubMed

Hellgren, E C; Vaughan, M R

1989-07-01

Rectal temperature was determined for 84 black bears (Ursus americanus) during 99 handlings in Great Dismal Swamp, Virginia and North Carolina (USA). All bears had been trapped with cable snares and immobilized with a 2:1 ketamine hydrochloridexylazine hydrochloride mixture. Temperatures were significantly greater in males and varied significantly by season. Immobilized bears began panting at rectal temperatures greater than 42.0 C. One death occurred at 43.0 C. We recommended cooling measures on black bears at rectal temperatures of greater than or equal to 40.0 C.

Cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST) is an effective and safe strategy for the management of non-lifting large laterally spreading colonic lesions.

PubMed

Tate, David J; Bahin, Farzan F; Desomer, Lobke; Sidhu, Mayenaaz; Gupta, Vikas; Bourke, Michael J

2018-01-01

 Non-lifting large laterally spreading colorectal lesions (LSLs) are challenging to resect endoscopically and often necessitate surgery. A safe, simple technique to treat non-lifting LSLs endoscopically with robust long-term outcomes has not been described.  In this single-center prospective observational study of consecutive patients referred for endoscopic mucosal resection (EMR) of LSLs ≥ 20 mm, LSLs not completely resectable by snare because of non-lifting underwent standardized completion of resection with cold-forceps avulsion and adjuvant snare-tip soft coagulation (CAST). Scheduled surveillance colonoscopies were performed at 4 - 6 months (SC1) and 18 months (SC2). Primary outcomes were endoscopic evidence of adenoma clearance and avoidance of surgery. The secondary outcome was safety.  From January 2012 to October 2016, 540 lifting LSLs (82.2 %) underwent complete snare excision at EMR. CAST was required for complete removal in 101 non-lifting LSLs (17.8 %): 63 naïve non-lifting lesions (NNLs; 62.7 %) and 38 previously attempted non-lifting lesions (PANLs; 37.3 %). PANLs were smaller ( P  < 0.001) and more likely to be non-granular ( P  = 0.001) than the lifting LSLs. NNLs were of similar size ( P  = 0.77) and morphology ( P  = 0.10) to the lifting LSLs. CAST was successful in all cases and adverse events were comparable to lifting LSLs resected by complete snare excision. Recurrence at SC1 was comparable for PANLs (15.2 %) and lifting LSLs (15.3 %; P  = 0.99), whereas NNLs recurred more frequently (27.5 %; P  = 0.049); however, surgery was no more common for either type of non-lifting LSL than for lifting LSLs.  CAST is a safe, effective, and surgery-sparing therapy for the majority of non-lifting LSLs. It is easy to use, inexpensive, and does not require additional equipment. © Georg Thieme Verlag KG Stuttgart · New York.

Genetic analysis of the role of amyloplasts in shoot gravisensing

NASA Astrophysics Data System (ADS)

Tasaka, M.; Morita, M.

Plant can change the growth direction after sensing the gravity orientation This response calls gravitropism and the initial step is the gravisensing We have isolated many Arabidopsis mutants shoot gravitropism sgr with reduced or no gravitropic response in inflorescence stems The analysis of sgr1 and sgr7 revealed that endoderm cells in the inflorescence stems were gravisensing sites zig zigzag sgr4 and sgr3 showed no or reduced gravitropism in shoot respectively and their amyloplasts thought to be statoliths did not sedimented to the orientation of gravity in the endoderm cells ZIG encoded a SNARE AtVTI11 and SGR3 encoded other SNARE AtVAM3 These two SNAREs made a complex in the shoot endoderm cells suggesting that the vesicle transport from trans-Golgi network TGN to prevacuolar compartment PVC and or vacuole was involved in the amyloplasts localization and movement The analysis to visualize amyloplasts and vacuolar membrane in living endoderm cells supported that the vacuole function was important for the amyloplasts movement Recently we have isolated many suppressor mutants of zig One of them named zig suppressor zip 1 had a point mutation in the gene encoded other SNARE of AtVTI12 This protein is a homologous to ZIG AtVTI11 and these two proteins have partially redundant functions Although wild type At VTI 12 could not rescued zig mutated AtVTI12 protein ZIP1 could almost completely play the part of ZIG In zigzip1 amyloplasts in endoderm cells sedimented normally and the shoots showed normal gravitropic response The other

The effects of ovarian biopsy and blood sampling methods on salivary cortisol and behaviour in sows.

PubMed

Yun, Jinhyeon; Björkman, Stefan; Pöytäkangas, Merja; Peltoniemi, Olli

2017-10-01

In reproductive physiology research, experimental animals are often subjected to stressful procedures, including blood sampling and biopsy. In this present study, presence of pain or distress induced by four different procedures was examined using a measurement of salivary cortisol levels and activity observations in sows. The treatments were: 1) PAL: The ovary was palpated through the rectum without snaring, 2) TUB: transvaginal ultrasound-guided biopsy of the ovary was conducted without snaring, 3) SNA: a soft rope snare was placed around the maxilla, 4) CAT: A soft rope snare was placed around the maxilla, and an intravenous catheter was inserted through the ear vein of the sows. Activities, social cohesion and other pain-related behaviour, and salivary cortisol concentrations were recorded. Salivary cortisol concentrations in CAT sows increased in response to the procedure (P<0.05), whereas the other treatments did not trigger a significant response. The CAT sows had higher cortisol concentrations than the other groups for 10min after initiation of the procedures (P<0.01), and they maintained higher cortisol levels than the PAL and TUB groups 15min post-treatment (P<0.05). Furthermore, the CAT sows showed the highest frequency of head shaking (P<0.001) and trembling behaviour (P<0.05) during the 1h post-treatment. Summarizing, the catheterization procedure might induce a short-term pain or stress response during and after the procedure in terms of pain-related behaviour and salivary cortisol status. We suggest that TUB might not cause appreciable pain or distress. Copyright © 2017 Elsevier Ltd. All rights reserved.

A molecular network for the transport of the TI-VAMP/VAMP7 vesicles from cell center to periphery.

PubMed

Burgo, Andrea; Proux-Gillardeaux, Véronique; Sotirakis, Emmanuel; Bun, Philippe; Casano, Alessandra; Verraes, Agathe; Liem, Ronald K H; Formstecher, Etienne; Coppey-Moisan, Maïté; Galli, Thierry

2012-07-17

The compartmental organization of eukaryotic cells is maintained dynamically by vesicular trafficking. SNARE proteins play a crucial role in intracellular membrane fusion and need to be targeted to their proper donor or acceptor membrane. The molecular mechanisms that allow for the secretory vesicles carrying the v-SNARE TI-VAMP/VAMP7 to leave the cell center, load onto microtubules, and reach the periphery to mediate exocytosis are largely unknown. Here, we show that the TI-VAMP/VAMP7 partner Varp, a Rab21 guanine nucleotide exchange factor, interacts with GolginA4 and the kinesin 1 Kif5A. Activated Rab21-GTP in turn binds to MACF1, an actin and microtubule regulator, which is itself a partner of GolginA4. These components are required for directed movement of TI-VAMP/VAMP7 vesicles from the cell center to the cell periphery. The molecular mechanisms uncovered here suggest an integrated view of the transport of vesicles carrying a specific v-SNARE toward the cell surface. Copyright © 2012 Elsevier Inc. All rights reserved.

Resection of giant right atrial lymphoma using vacuum-assisted cardiopulmonary bypass without snaring the inferior vena cava.

PubMed

Shin, Hankei; Mori, Mitsuharu; Matayoshi, Toru; Suzuki, Ryo; Yozu, Ryohei

2004-08-01

A 53-year-old man sustained hemodynamic collapse due to a huge right atrial tumor and was transferred to our hospital and underwent a life-saving emergency operation. The tumor arose from the inferolateral wall of the right atrium, occupying almost the whole right atrial cavity and obstructing not only the inflow of the right ventricle but also the orifice of the inferior vena cava. Venous cannulation via the right atrial wall and placing a snare around the inferior vena cava were impossible. With a cardiopulmonary bypass using vacuum-assisted venous drainage, the tumor was successfully resected and the tricuspid valve was replaced with a bioprosthetic valve without snaring the inferior vena cava. Postoperative histological examination demonstrated the tumor to be a large B-cell non-Hodgkin type malignant lymphoma. When the tumor is large and it is difficult to establish total cardiopulmonary bypass, the vacuum-assisted cardiopulmonary bypass is a useful option. This can achieve a bloodless operative field and is not blocked by the incoming air, due to the venous drainage being continually pressure-regulated.

The postsynaptic t-SNARE Syntaxin 4 controls traffic of Neuroligin 1 and Synaptotagmin 4 to regulate retrograde signaling.

PubMed

Harris, Kathryn P; Zhang, Yao V; Piccioli, Zachary D; Perrimon, Norbert; Littleton, J Troy

2016-05-25

Postsynaptic cells can induce synaptic plasticity through the release of activity-dependent retrograde signals. We previously described a Ca(2+)-dependent retrograde signaling pathway mediated by postsynaptic Synaptotagmin 4 (Syt4). To identify proteins involved in postsynaptic exocytosis, we conducted a screen for candidates that disrupted trafficking of a pHluorin-tagged Syt4 at Drosophila neuromuscular junctions (NMJs). Here we characterize one candidate, the postsynaptic t-SNARE Syntaxin 4 (Syx4). Analysis of Syx4 mutants reveals that Syx4 mediates retrograde signaling, modulating the membrane levels of Syt4 and the transsynaptic adhesion protein Neuroligin 1 (Nlg1). Syx4-dependent trafficking regulates synaptic development, including controlling synaptic bouton number and the ability to bud new varicosities in response to acute neuronal stimulation. Genetic interaction experiments demonstrate Syx4, Syt4, and Nlg1 regulate synaptic growth and plasticity through both shared and parallel signaling pathways. Our findings suggest a conserved postsynaptic SNARE machinery controls multiple aspects of retrograde signaling and cargo trafficking within the postsynaptic compartment.

Strategies for the Management of SVC Stent Migration into the Right Atrium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, J. D., E-mail: drjeremytaylor@yahoo.co.uk; Lehmann, E. D.; Belli, A.-M.

Purpose. Stent migration into the right atrium is a potentially fatal complication of stenting in the venous system and is most likely to occur during the treatment of superior vena cava obstruction. Endovascular approaches that can salvage this hazardous situation are described and the keys to successful treatment are highlighted. Materials and Methods. Four different strategies are reviewed: (1) snaring the stent directly, (2) angioplasty balloon-assisted snaring of the stent, (3) guide wire-assisted snaring of the stent, and (4) superior vena cava-to-inferior vena cava bridging stent. Results. These techniques have been employed in the successful management of four cases. Nomore » short- or long-term complications as a result of these maneuvers have been identified. Additional treatment of the underlying disease was possible at the same time in each case. Conclusion. We conclude that prompt management of right atrial stent migration is essential and can be successfully achieved by a variety of 'bale-out' techniques which are within the technical range of most interventional radiologists.« less

Direct quantitative detection of Doc2b-induced hemifusion in optically trapped membranes

NASA Astrophysics Data System (ADS)

Brouwer, Ineke; Giniatullina, Asiya; Laurens, Niels; van Weering, Jan R. T.; Bald, Dirk; Wuite, Gijs J. L.; Groffen, Alexander J.

2015-09-01

Ca2+-sensor proteins control the secretion of many neuroendocrine substances. Calcium-secretion coupling may involve several mechanisms. First, Ca2+-dependent association of their tandem C2 domains with phosphatidylserine may induce membrane curvature and thereby enhance fusion. Second, their association with SNARE complexes may inhibit membrane fusion in the absence of a Ca2+ trigger. Here we present a method using two optically trapped beads coated with SNARE-free synthetic membranes to elucidate the direct role of the C2AB domain of the soluble Ca2+-sensor Doc2b. Contacting membranes are often coupled by a Doc2b-coated membrane stalk that resists forces up to 600 pN upon bead separation. Stalk formation depends strictly on Ca2+ and phosphatidylserine. Real-time fluorescence imaging shows phospholipid but not content mixing, indicating membrane hemifusion. Thus, Doc2b acts directly on membranes and stabilizes the hemifusion intermediate in this cell-free system. In living cells, this mechanism may co-occur with progressive SNARE complex assembly, together defining Ca2+-secretion coupling.

STS-119 EVA 3 GAT SSRMS LEE B Snare Lubrication OPS

NASA Image and Video Library

2009-03-23

S119-E-007105 (23 March 2009) --- Astronaut Richard Arnold, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Arnold and Joseph Acaba (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors required during Trypanosoma cruzi parasitophorous vacuole development.

PubMed

Cueto, Juan Agustín; Vanrell, María Cristina; Salassa, Betiana Nebaí; Nola, Sébastien; Galli, Thierry; Colombo, María Isabel; Romano, Patricia Silvia

2017-06-01

Trypanosoma cruzi, the etiologic agent of Chagas disease, is an obligate intracellular parasite that exploits different host vesicular pathways to invade the target cells. Vesicular and target soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are key proteins of the intracellular membrane fusion machinery. During the early times of T. cruzi infection, several vesicles are attracted to the parasite contact sites in the plasma membrane. Fusion of these vesicles promotes the formation of the parasitic vacuole and parasite entry. In this work, we study the requirement and the nature of SNAREs involved in the fusion events that take place during T. cruzi infection. Our results show that inhibition of N-ethylmaleimide-sensitive factor protein, a protein required for SNARE complex disassembly, impairs T. cruzi infection. Both TI-VAMP/VAMP7 and cellubrevin/VAMP3, two v-SNAREs of the endocytic and exocytic pathways, are specifically recruited to the parasitophorous vacuole membrane in a synchronized manner but, although VAMP3 is acquired earlier than VAMP7, impairment of VAMP3 by tetanus neurotoxin fails to reduce T. cruzi infection. In contrast, reduction of VAMP7 activity by expression of VAMP7's longin domain, depletion by small interfering RNA or knockout, significantly decreases T. cruzi infection susceptibility as a result of a minor acquisition of lysosomal components to the parasitic vacuole. In addition, overexpression of the VAMP7 partner Vti1b increases the infection, whereas expression of a KIF5 kinesin mutant reduces VAMP7 recruitment to vacuole and, concomitantly, T. cruzi infection. Altogether, these data support a key role of TI-VAMP/VAMP7 in the fusion events that culminate in the T. cruzi parasitophorous vacuole development. © 2016 John Wiley & Sons Ltd.

Multiple functions of the SNARE protein Snap29 in autophagy, endocytic, and exocytic trafficking during epithelial formation in Drosophila.

PubMed

Morelli, Elena; Ginefra, Pierpaolo; Mastrodonato, Valeria; Beznoussenko, Galina V; Rusten, Tor Erik; Bilder, David; Stenmark, Harald; Mironov, Alexandre A; Vaccari, Thomas

2014-01-01

How autophagic degradation is linked to endosomal trafficking routes is little known. Here we screened a collection of uncharacterized Drosophila mutants affecting membrane transport to identify new genes that also have a role in autophagy. We isolated a loss of function mutant in Snap29 (Synaptosomal-associated protein 29 kDa), the gene encoding the Drosophila homolog of the human protein SNAP29 and have characterized its function in vivo. Snap29 contains 2 soluble NSF attachment protein receptor (SNARE) domains and a asparagine-proline-phenylalanine (NPF motif) at its N terminus and rescue experiments indicate that both SNARE domains are required for function, whereas the NPF motif is in part dispensable. We find that Snap29 interacts with SNARE proteins, localizes to multiple trafficking organelles, and is required for protein trafficking and for proper Golgi apparatus morphology. Developing tissue lacking Snap29 displays distinctive epithelial architecture defects and accumulates large amounts of autophagosomes, highlighting a major role of Snap29 in autophagy and secretion. Mutants for autophagy genes do not display epithelial architecture or secretion defects, suggesting that the these alterations of the Snap29 mutant are unlikely to be caused by the impairment of autophagy. In contrast, we find evidence of elevated levels of hop-Stat92E (hopscotch-signal transducer and activator of transcription protein at 92E) ligand, receptor, and associated signaling, which might underlie the epithelial defects. In summary, our findings support a role of Snap29 at key steps of membrane trafficking, and predict that signaling defects may contribute to the pathogenesis of cerebral dysgenesis, neuropathy, ichthyosis, and palmoplantar keratoderma (CEDNIK), a human congenital syndrome due to loss of Snap29.

Coarse-Grain Simulations Reveal Movement of the Synaptobrevin C-Terminus in Response to Piconewton Forces

PubMed Central

Lindau, Manfred; Hall, Benjamin A.; Chetwynd, Alan; Beckstein, Oliver; Sansom, Mark S.P.

2012-01-01

Fusion of neurosecretory vesicles with the plasma membrane is mediated by SNARE proteins, which transfer a force to the membranes. However, the mechanism by which this force transfer induces fusion pore formation is still unknown. The neuronal vesicular SNARE protein synaptobrevin 2 (syb2) is anchored in the vesicle membrane by a single C-terminal transmembrane (TM) helix. In coarse-grain molecular-dynamics simulations, self-assembly of the membrane occurred with the syb2 TM domain inserted, as expected from experimental data. The free-energy profile for the position of the syb2 membrane anchor in the membrane was determined using umbrella sampling. To predict the free-energy landscapes for a reaction pathway pulling syb2 toward the extravesicular side of the membrane, which is the direction of the force transfer from the SNARE complex, harmonic potentials were applied to the peptide in its unbiased position, pulling it toward new biased equilibrium positions. Application of piconewton forces to the extravesicular end of the TM helix in the simulation detached the synaptobrevin C-terminus from the vesicle's inner-leaflet lipid headgroups and pulled it deeper into the membrane. This C-terminal movement was facilitated and hindered by specific mutations in parallel with experimentally observed facilitation and inhibition of fusion. Direct application of such forces to the intravesicular end of the TM domain resulted in tilting motion of the TM domain through the membrane with an activation energy of ∼70 kJ/mol. The results suggest a mechanism whereby fusion pore formation is induced by movement of the charged syb2 C-terminus within the membrane in response to pulling and tilting forces generated by C-terminal zippering of the SNARE complex. PMID:23009845

Coarse-grain simulations reveal movement of the synaptobrevin C-terminus in response to piconewton forces.

PubMed

Lindau, Manfred; Hall, Benjamin A; Chetwynd, Alan; Beckstein, Oliver; Sansom, Mark S P

2012-09-05

Fusion of neurosecretory vesicles with the plasma membrane is mediated by SNARE proteins, which transfer a force to the membranes. However, the mechanism by which this force transfer induces fusion pore formation is still unknown. The neuronal vesicular SNARE protein synaptobrevin 2 (syb2) is anchored in the vesicle membrane by a single C-terminal transmembrane (TM) helix. In coarse-grain molecular-dynamics simulations, self-assembly of the membrane occurred with the syb2 TM domain inserted, as expected from experimental data. The free-energy profile for the position of the syb2 membrane anchor in the membrane was determined using umbrella sampling. To predict the free-energy landscapes for a reaction pathway pulling syb2 toward the extravesicular side of the membrane, which is the direction of the force transfer from the SNARE complex, harmonic potentials were applied to the peptide in its unbiased position, pulling it toward new biased equilibrium positions. Application of piconewton forces to the extravesicular end of the TM helix in the simulation detached the synaptobrevin C-terminus from the vesicle's inner-leaflet lipid headgroups and pulled it deeper into the membrane. This C-terminal movement was facilitated and hindered by specific mutations in parallel with experimentally observed facilitation and inhibition of fusion. Direct application of such forces to the intravesicular end of the TM domain resulted in tilting motion of the TM domain through the membrane with an activation energy of ∼70 kJ/mol. The results suggest a mechanism whereby fusion pore formation is induced by movement of the charged syb2 C-terminus within the membrane in response to pulling and tilting forces generated by C-terminal zippering of the SNARE complex. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

The pollen-specific R-SNARE/longin PiVAMP726 mediates fusion of endo- and exocytic compartments in pollen tube tip growth

PubMed Central

Guo, Feng; McCubbin, Andrew G.

2012-01-01

The growing pollen tube apex is dedicated to balancing exo- and endocytic processes to form a rapidly extending tube. As perturbation of either tends to cause a morphological phenotype, this system provides tractable model for studying these processes. Vesicle-associated membrane protein 7s (VAMP7s) are members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family that mediate cognate membrane fusion but their role in pollen tube growth has not been investigated. This manuscript identifies PiVAMP726 of Petunia inflata as a pollen-specific VAMP7 that localizes to the inverted cone of transport vesicles at the pollen tube tip. The endocytic marker FM4-64 was found to colocalize with yellow fluorescent protein (YFP)-PiVAMP726, which is consistent with PiVAMP726 containing an amino-acid motif implicated in endosomal localization, At high overexpression levels, YFP- PiVAMP726 inhibited growth and caused the formation of novel membrane compartments within the pollen tube tip. Functional dissection of PiVAMP726 implicated the N-terminal longin domain in negative regulation of the SNARE activity, but not localization of PiVAMP726. Expression of the constitutively active C-terminal SNARE domain alone, in pollen tubes, generated similar phenotypes to the full-length protein, but the truncated domain was more potent than the wild-type protein at both inhibiting growth and forming the novel membrane compartments. Both endo- and exocytic markers localized to these compartments in addition to YFP-PiVAMP726, leading to the speculation that PiVAMP726 might be involved in the recycling of endocytic vesicles in tip growth. PMID:22345643

Utility of Amplatzer Vascular Plug with Preoperative Common Hepatic Artery Embolization for Distal Pancreatectomy with En Bloc Celiac Axis Resection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toguchi, Masafumi, E-mail: e024163@yahoo.co.jp; Tsurusaki, Masakatsu; Numoto, Isao

PurposeTo evaluate the feasibility and safety of the Amplatzer vascular plug (AVP) for preoperative common hepatic embolization (CHA) before distal pancreatectomy with en bloc celiac axis resection (DP-CAR) to redistribute blood flow to the stomach and liver via the superior mesenteric artery (SMA).Materials and MethodsFour patients (3 males, 1 female; median age 69 years) with locally advanced pancreatic body cancer underwent preoperative CHA embolization with AVP. After embolization, SMA arteriography was performed to confirm the alteration of blood flow from the SMA to the proper hepatic artery.ResultsIn three of four patients, technical successes were achieved with sufficient margin from the originmore » of gastroduodenal artery. In one patient, the margin was less than 5 mm, although surgery was successfully performed without any problem. Eventually, all patients underwent the DP-CAR without arterial reconstruction or liver ischemia.ConclusionsAVP application is feasible and safe as an embolic procedure for preoperative CHA embolization of DP-CAR.« less

Amplatzer Vascular Plug Anchoring Technique to Stabilize the Delivery System for Microcoil Embolization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onozawa, Shiro, E-mail: onozawa@nms.ac.jp; Murata, Satoru, E-mail: genji@nms.ac.jp; Mine, Takahiko, E-mail: takahikomine@gmail.com

PurposeTo evaluate the feasibility of a novel embolization technique, the Amplatzer vascular plug (AVP) anchoring technique, to stabilize the delivery system for microcoil embolization.Materials and methodsThree patients were enrolled in this study, including two cases of internal iliac artery aneurysms and one case of internal iliac arterial occlusion prior to endovascular aortic repair. An AVP was used in each case for embolization of one target artery, and the AVP was left in place. The AVP detachment wire was then used as an anchor to stabilize the delivery system for microcoil embolization to embolize the second target artery adjacent to themore » first target artery. The microcatheter for the microcoils was inserted parallel to the AVP detachment wire in the guiding sheath or catheter used for the AVP.ResultsThe AVP anchoring technique was achieved and the microcatheter was easily advanced to the second target artery in all three cases.ConclusionThe AVP anchoring technique was found to be feasible to advance the microcatheter into the neighboring artery of an AVP-embolized artery.« less

Treatment of a Common Iliac Aneurysm by Endovascular Exclusion Using the Amplatzer Vascular Plug and Femorofemoral Crossover Graft

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coupe, Nicholas J., E-mail: optimus2050@hotmail.com; Ling, Lynn; Cowling, Mark G.

2009-07-15

We report our initial experience using the Amplatzer Vascular Plug II (AVP2) in the treatment of a left common iliac aneurysm. Following investigation by computerized tomographic angiography and catheter angiography, a 79-year-old man was found to have a markedly tortuous iliac system, with a left common iliac artery aneurysm that measured 48 mm in maximal diameter. Due to the patient's age and comorbidities the surgical opinion was that conventional open repair was not suitable. However, due to the tortuous nature of the aneurysm and iliac vessels, standard endovascular repair, using either a bifurcated or an aorto-uni-iliac stent graft, was alsomore » not possible. A combined approach was used by embolizing the ipsilateral internal iliac artery using coils and excluding the aneurysm using two AVP2 occlusion devices, followed by femorofemoral crossover grafting. Total aneurysm occlusion was achieved using this method and this allowed the patient to have a much less invasive surgical procedure than with conventional open repair of common iliac aneurysms, thus avoiding potential comorbidity and mortality.« less

Percutaneous Closure of Patent Foramen Ovale in Patients With Migraine: The PREMIUM Trial.

PubMed

Tobis, Jonathan M; Charles, Andrew; Silberstein, Stephen D; Sorensen, Sherman; Maini, Brijeshwar; Horwitz, Phillip A; Gurley, John C

2017-12-05

Migraine is a prevalent and disabling disorder. Patent foramen ovale (PFO) has been associated with migraine, but its role in the disorder remains poorly understood. This study examined the efficacy of percutaneous PFO closure as a therapy for migraine with or without aura. The PREMIUM (Prospective, Randomized Investigation to Evaluate Incidence of Headache Reduction in Subjects With Migraine and PFO Using the AMPLATZER PFO Occluder to Medical Management) was a double-blind study investigating migraine characteristics over 1 year in subjects randomized to medical therapy with a sham procedure (right heart catheterization) versus medical therapy and PFO closure with the Amplatzer PFO Occluder device (St. Jude Medical, St. Paul, Minnesota). Subjects had 6 to 14 days of migraine per month, had failed at least 3 migraine preventive medications, and had significant right-to-left shunt defined by transcranial Doppler. Primary endpoints were responder rate defined as 50% reduction in migraine attacks and adverse events. Secondary endpoints included reduction in migraine days and efficacy in patients with versus without aura. Of 1,653 subjects consented, 230 were enrolled. There was no difference in responder rate in the PFO closure (45 of 117) versus control (33 of 103) groups. One serious adverse event (transient atrial fibrillation) occurred in 205 subjects who underwent PFO closure. Subjects in the PFO closure group had a significantly greater reduction in headache days (-3.4 vs. -2.0 days/month, p = 0.025). Complete migraine remission for 1 year occurred in 10 patients (8.5%) in the treatment group versus 1 (1%) in the control group (p = 0.01). PFO closure did not meet the primary endpoint of reduction in responder rate in patients with frequent migraine. (Prospective, Randomized Investigation to Evaluate Incidence of Headache Reduction in Subjects With Migraine and PFO Using the AMPLATZER PFO Occluder to Medical Management [PREMIUM]; NCT00355056). Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Enhanced, rapid occlusion of carotid and vertebral arteries using the AMPLATZER Vascular Plug II device: the Duke Cerebrovascular Center experience in 8 patients with 22 AMPLATZER Vascular Plug II devices.

PubMed

Mihlon, Frank; Agrawal, Abishek; Nimjee, Shahid M; Ferrell, Andrew; Zomorodi, Ali R; Smith, Tony P; Britz, Gavin W

2015-01-01

Therapeutic embolization of the common carotid artery (CCA), internal carotid artery (ICA), and vertebral artery (VA) is necessary in the treatment of a subset of chronic arteriovenous fistulas (AVFs), hemorrhages, highly vascularized neoplasms before resection, and giant aneurysms. There are currently no reports of the use of the AMPLATZER Vascular Plug II (AVP II) device to occlude the CCA, ICA, or VA. The objective of this article is to present the Duke Cerebrovascular Center experience using the AVP II device in neurointerventional applications. This case series is a retrospective review of all of the cases at Duke University Hospital in which an AVP II device was used in the CCA, ICA, or VA up to September 2012. The AVP II device was often used in conjunction with embolization coils or as multiple AVP II devices deployed in tandem. During 2010-2012, 8 cases meeting criteria were performed. These included 2 chronic VA to internal jugular AVFs, 1 hemorrhagic CCA to internal jugular AVF secondary to invasive head and neck squamous cell carcinoma, 1 ICA hemorrhage secondary to invasive head and neck squamous cell carcinoma, 1 ICA hemorrhage secondary to trauma, 1 ruptured ICA aneurysm, 1 giant petrous ICA aneurysm, and 1 case of cervical vertebral sarcoma requiring preoperative VA embolization. Successful occlusion of the target vessel was achieved in all 8 cases. There was 1 major complication that consisted of a watershed distribution cerebral infarct; however, this was related to emergent occlusion of the ICA in the setting of intracranial hemorrhage and was not a problem intrinsic to the AVP II device. The AVP II device is relatively large, self-expanding vascular occlusion device that safely allows enhanced, rapid take-down of the CCA, ICA, and VA with low risk of distal migration. Copyright © 2015 Elsevier Inc. All rights reserved.

[A case of polypoid bronchial neurofibroma originating from right B2b successfully treated by bronchoscopic snaring forceps and Nd-YAG laser therapy].

PubMed

Takiguchi, Y; Uchiyama, T; Sato, K; Tatsumi, K; Kimura, H; Nagao, K; Fujisawa, T; Ohwada, H; Hiroshima, K; Kuriyama, T

1993-12-01

A 34-year-old man with persistent cough was admitted to our hospital. Bronchoscopic examination revealed a polypoid tumor with smooth surface which almost completely obstructed the right main bronchus. The tumor was removed by transbronchial snaring forceps and histologically confirmed as neurofibroma. Residual tumor was excised by biopsy forceps and further endoscopic Nd-YAG laser vaporization was performed. This is the first case in our country in which bronchoscopic treatment was performed for bronchial neurofibroma. Bronchoscopic removal might be the preferred treatment in the present case, although long-term follow-up is also required.

STS-119 Extravehicular Activity (EVA) 3 GAT SSRMS LEE B Snare Lubrication OPS

NASA Image and Video Library

2009-03-23

S119-E-007469 (23 March 2009) --- Astronaut Richard Arnold, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Arnold and Joseph Acaba (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 GAT SSRMS LEE B Snare Lubrication OPS

NASA Image and Video Library

2009-03-23

S119-E-007398 (23 March 2009) --- Astronaut Richard Arnold, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Arnold and Joseph Acaba (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

Snare-assisted anterograde balloon mitral and aortic valvotomy using Inoue balloon catheter.

PubMed

Krishnan, Mangalath N; Syamkumar, M D; Sajeev, C G; Venugopal, K; Johnson, Francis; Vinaykumar, D; Velayudhan, C C; Jayakumar, T G

2007-01-02

We performed concurrent antegrade mitral and aortic valvotomy using Inoue dilatation catheter in 3 cases of combined rheumatic mitral and aortic stenosis. Following mitral valvotomy by standard procedure, aortic valve was crossed with the help of a floatation catheter. Stiff long length guide wire was fixed in descending aorta using a snare. Inoue catheter was threaded over the wire across the aortic valve and aortic valvotomy completed. Mitral valve area increased from mean 1 cm2 to 2 cm2; aortic gradient dropped from mean of 97 mm to 36 mm. Concurrent anterograde balloon mitral and aortic valvotomy may be effective and safe.

Assessment of Snared-Loop Technique When Standard Retrieval of Inferior Vena Cava Filters Fails

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doody, Orla, E-mail: orla_doody@hotmail.com; Noe, Geertje; Given, Mark F.

Purpose To identify the success and complications related to a variant technique used to retrieve inferior vena cava filters when simple snare approach has failed. Methods A retrospective review of all Cook Guenther Tulip filters and Cook Celect filters retrieved between July 2006 and February 2008 was performed. During this period, 130 filter retrievals were attempted. In 33 cases, the standard retrieval technique failed. Retrieval was subsequently attempted with our modified retrieval technique. Results The retrieval was successful in 23 cases (mean dwell time, 171.84 days; range, 5-505 days) and unsuccessful in 10 cases (mean dwell time, 162.2 days; range,more » 94-360 days). Our filter retrievability rates increased from 74.6% with the standard retrieval method to 92.3% when the snared-loop technique was used. Unsuccessful retrieval was due to significant endothelialization (n = 9) and caval penetration by the filter (n = 1). A single complication occurred in the group, in a patient developing pulmonary emboli after attempted retrieval. Conclusion The technique we describe increased the retrievability of the two filters studied. Hook endothelialization is the main factor resulting in failed retrieval and continues to be a limitation with these filters.« less

Density drives polyandry and relatedness influences paternal success in the Pacific gooseneck barnacle, Pollicipes elegans

PubMed Central

2014-01-01

Background Polyandry is a common mating strategy in animals, increasing female fitness through direct (material) and indirect (genetic) benefits. Most theories about the benefits of polyandry come from studies of terrestrial animals, which have relatively complex mating systems and behaviors; less is known about the potential benefits of polyandry in sessile marine animals, for which potential mates may be scarce and females have less control over pre-copulatory mate choice. Here, we used microsatellite markers to examine multiple paternity in natural aggregations of the Pacific gooseneck barnacle Pollicipes elegans, testing the effect of density on paternity and mate relatedness on male reproductive success. Results We found that multiple paternity was very common (79% of broods), with up to five fathers contributing to a brood, though power was relatively low to detect more than four fathers. Density had a significant and positive linear effect on the number of fathers siring a brood, though this relationship leveled off at high numbers of fathers, which may reflect a lack of power and/or an upper limit to polyandry in this species. Significant skew in male reproductive contribution in multiply-sired broods was observed and we found a positive and significant relationship between the proportion of offspring sired and the genetic similarity between mates, suggesting that genetic compatibility may influence reproductive success in this species. Conclusions To our knowledge, this is the first study to show high levels of multiple paternity in a barnacle, and overall, patterns of paternity in P. elegans appear to be driven primarily by mate availability. Evidence of paternity bias for males with higher relatedness suggests some form of post-copulatory sexual selection is taking place, but more work is needed to determine whether it operates during or post-fertilization. Overall, our results suggest that while polyandry in P. elegans is driven by mate availability, it may also provide a mechanism for females to ensure fertilization by compatible gametes and increase reproductive success in this sessile species. PMID:24739102

Transhepatic Embolization of Congenital Intrahepatic Portosystemic Venous Shunts with Associated Aneurysms

PubMed Central

Paudel, Kalyan; Hoffer, Eric K.

2015-01-01

Intrahepatic shunts between the portal and systemic venous systems with associated aneurysms are extremely rare. A middle aged woman presented with hepatic encephalopathy and was found to have two intrahepatic portosystemic venous shunts with associated aneurysms. Diagnosis was made by duplex ultrasound and was confirmed with contrast enhanced MRI. Treatment was performed percutaneously with an Amplatzer vascular plug. PMID:26257785

Effects of transcatheter closure of Fontan fenestration on exercise tolerance. kidecho@yahoo.com.

PubMed

Momenah, Tarek S; Eltayb, Haifa; Oakley, Reida El; Qethamy, Howeida Al; Faraidi, Yahya Al

2008-05-01

Baffle fenestration is associated with a significantly better outcome in standard and high-risk patients undergoing completion of Fontan. We report the effects of subsequent transcatheter closure of fenestration on exercise capacity and oxygen saturation. Sixteen patients with a mean age of 10.3 years underwent Amplatzer septal occluder (ASO) device transcatheter closure of Fontan fenestration. All had a fenestrated Fontan operation 6 month to 8 years prior to the procedure. A stress test was performed before and after device closure of fenestration in 14 patients (2 patients did not tolerate stress test before the procedure). The fenestrations in all patients were successfully occluded with the use of the Amplatzer device occluder. No complications occurred during or after the procedure. O2 saturation increased from a mean 85.1 +/- 7.89% to 94.5 +/- 3.63% (p < 0.01) at rest and from 66.2 +/- 12.86% to 87.2 +/- 8.64% (p < 0.01) following exercise. Exercise duration has also increased from 8.22 +/- 2.74 min to 10.29 +/- 1.91 min (p < 0.05). Transcatheter closure of Fontan fenestration increases the duration of exercise capacity and increases O2 saturation at rest and after exercise.

Transcatheter closure of moderate-to-large patent ductus arteriosus in infants using Amplatzer duct occluder.

PubMed

Wang, Jou-Kou; Wu, Mei-Hwan; Lin, Ming-Tai; Chiu, Shuenn-Nan; Chen, Chun-An; Chiu, Hsin-Hui

2010-02-01

There are difficulties in transcatheter closure of patent ductus arteriosus (PDA) in infants. The 46 infants (mean age 6.2+/-2.7 months; mean body weight 6.3+/-1.6 kg) who underwent PDA closure using the Amplatzer duct occluder (ADO). The indication for using an ADO was a ductus diameter > or =2.5 or 3 mm. Device diameter selected was 1-3 mm larger than ductal diameter. The mean systolic pulmonary artery pressure was 40.9+/-18.2 mmHg. The mean Qp/Qs ratio was 3.1+/-1.2. The mean ductus diameter was 3.3+/-0.8 mm. ADO was successfully deployed in 45 patients. Failure occurred in 1 case. The mean diameter of device used was 5.4+/-1.1 mm. No severe complications occurred. At the 1-month echocardiographic follow-up, a small residual shunt was present in 4 of 45 patients and had disappeared in all 4 patients at the 3-month follow-up. One patient developed a moderate degree of left ventricular outflow tract obstruction 2.3 years after the procedure. Transcatheter closure of PDA in infants using the ADO is a safe and effective method.

LRRK2 phosphorylates pre-synaptic N-ethylmaleimide sensitive fusion (NSF) protein enhancing its ATPase activity and SNARE complex disassembling rate.

PubMed

Belluzzi, Elisa; Gonnelli, Adriano; Cirnaru, Maria-Daniela; Marte, Antonella; Plotegher, Nicoletta; Russo, Isabella; Civiero, Laura; Cogo, Susanna; Carrion, Maria Perèz; Franchin, Cinzia; Arrigoni, Giorgio; Beltramini, Mariano; Bubacco, Luigi; Onofri, Franco; Piccoli, Giovanni; Greggio, Elisa

2016-01-13

Lrrk2, a gene linked to Parkinson's disease, encodes a large scaffolding protein with kinase and GTPase activities implicated in vesicle and cytoskeletal-related processes. At the presynaptic site, LRRK2 associates with synaptic vesicles through interaction with a panel of presynaptic proteins. Here, we show that LRRK2 kinase activity influences the dynamics of synaptic vesicle fusion. We therefore investigated whether LRRK2 phosphorylates component(s) of the exo/endocytosis machinery. We have previously observed that LRRK2 interacts with NSF, a hexameric AAA+ ATPase that couples ATP hydrolysis to the disassembling of SNARE proteins allowing them to enter another fusion cycle during synaptic exocytosis. Here, we demonstrate that NSF is a substrate of LRRK2 kinase activity. LRRK2 phosphorylates full-length NSF at threonine 645 in the ATP binding pocket of D2 domain. Functionally, NSF phosphorylated by LRRK2 displays enhanced ATPase activity and increased rate of SNARE complex disassembling. Substitution of threonine 645 with alanine abrogates LRRK2-mediated increased ATPase activity. Given that the most common Parkinson's disease LRRK2 G2019S mutation displays increased kinase activity, our results suggest that mutant LRRK2 may impair synaptic vesicle dynamics via aberrant phosphorylation of NSF.

The Vici Syndrome Protein EPG5 Is a Rab7 Effector that Determines the Fusion Specificity of Autophagosomes with Late Endosomes/Lysosomes.

PubMed

Wang, Zheng; Miao, Guangyan; Xue, Xue; Guo, Xiangyang; Yuan, Chongzhen; Wang, Zhaoyu; Zhang, Gangming; Chen, Yingyu; Feng, Du; Hu, Junjie; Zhang, Hong

2016-09-01

Mutations in the human autophagy gene EPG5 cause the multisystem disorder Vici syndrome. Here we demonstrated that EPG5 is a Rab7 effector that determines the fusion specificity of autophagosomes with late endosomes/lysosomes. EPG5 is recruited to late endosomes/lysosomes by direct interaction with Rab7 and the late endosomal/lysosomal R-SNARE VAMP7/8. EPG5 also binds to LC3/LGG-1 (mammalian and C. elegans Atg8 homolog, respectively) and to assembled STX17-SNAP29 Qabc SNARE complexes on autophagosomes. EPG5 stabilizes and facilitates the assembly of STX17-SNAP29-VAMP7/8 trans-SNARE complexes, and promotes STX17-SNAP29-VAMP7-mediated fusion of reconstituted proteoliposomes. Loss of EPG5 activity causes abnormal fusion of autophagosomes with various endocytic vesicles, in part due to elevated assembly of STX17-SNAP25-VAMP8 complexes. SNAP25 knockdown partially suppresses the autophagy defect caused by EPG5 depletion. Our study reveals that EPG5 is a Rab7 effector involved in autophagosome maturation, providing insight into the molecular mechanism underlying Vici syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.

The golgin protein Coy1 functions in intra-Golgi retrograde transport and interacts with the COG complex and Golgi SNAREs

PubMed Central

Anderson, Nadine S.; Mukherjee, Indrani; Bentivoglio, Christine M.; Barlowe, Charles

2017-01-01

Extended coiled-coil proteins of the golgin family play prominent roles in maintaining the structure and function of the Golgi complex. Here we further investigate the golgin protein Coy1 and document its function in retrograde transport between early Golgi compartments. Cells that lack Coy1 displayed a reduced half-life of the Och1 mannosyltransferase, an established cargo of intra-Golgi retrograde transport. Combining the coy1Δ mutation with deletions in other putative retrograde golgins (sgm1Δ and rud3Δ) caused strong glycosylation and growth defects and reduced membrane association of the conserved oligomeric Golgi (COG) complex. In contrast, overexpression of COY1 inhibited the growth of mutant strains deficient in fusion activity at the Golgi (sed5-1 and sly1-ts). To map Coy1 protein interactions, coimmunoprecipitation experiments revealed an association with the COG complex and with intra-Golgi SNARE proteins. These physical interactions are direct, as Coy1 was efficiently captured in vitro by Lobe A of the COG complex and the purified SNARE proteins Gos1, Sed5, and Sft1. Thus our genetic, in vivo, and biochemical data indicate a role for Coy1 in regulating COG complex-dependent fusion of retrograde-directed COPI vesicles. PMID:28794270

Function suggests nano-structure: towards a unified theory for secretion rate, a statistical mechanics approach.

PubMed

Hammel, Ilan; Meilijson, Isaac

2013-11-06

The inventory of secretory granules along the plasma membrane can be viewed as maintained in two restricted compartments. The release-ready pool represents docked granules available for an initial stage of fast, immediate secretion, followed by a second stage of granule set-aside secretion pool, with significantly slower rate. Transmission electron microscopy ultra-structural investigations correlated with electrophysiological techniques and mathematical modelling have allowed the categorization of these secretory vesicle compartments, in which vesicles can be in various states of secretory competence. Using the above-mentioned approaches, the kinetics of single vesicle exocytosis can be worked out. The ultra-fast kinetics, explored in this study, represents the immediately available release-ready pool, in which granules bound to the plasma membrane are exocytosed upon Ca(2+) influx at the SNARE rosette at the base of porosomes. Formalizing Dodge and Rahamimoff findings on the effect of calcium concentration and incorporating the effect of SNARE transient rosette size, we postulate that secretion rate (rate), the number (X) of intracellular calcium ions available for fusion, calcium capacity (0 ≤ M ≤ 5) and the fusion nano-machine size (as measured by the SNARE rosette size K) satisfy the parsimonious M-K relation rate ≈ C × [Ca(2+)](min(X,M))e(-K/2).

Myosin IIA participates in docking of Glut4 storage vesicles with the plasma membrane in 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Le Thi Kim, E-mail: ngocanh@nutr.med.tokushima-u.ac.jp; Hosaka, Toshio; Harada, Nagakatsu

2010-01-01

In adipocytes and myocytes, insulin stimulation translocates glucose transporter 4 (Glut4) storage vesicles (GSVs) from their intracellular storage sites to the plasma membrane (PM) where they dock with the PM. Then, Glut4 is inserted into the PM and initiates glucose uptake into these cells. Previous studies using chemical inhibitors demonstrated that myosin II participates in fusion of GSVs and the PM and increase in the intrinsic activity of Glut4. In this study, the effect of myosin IIA on GSV trafficking was examined by knocking down myosin IIA expression. Myosin IIA knockdown decreased both glucose uptake and exposures of myc-tagged Glut4more » to the cell surface in insulin-stimulated cells, but did not affect insulin signal transduction. Interestingly, myosin IIA knockdown failed to decrease insulin-dependent trafficking of Glut4 to the PM. Moreover, in myosin IIA knockdown cells, insulin-stimulated binding of GSV SNARE protein, vesicle-associated membrane protein 2 (VAMP2) to PM SNARE protein, syntaxin 4 was inhibited. These data suggest that myosin IIA plays a role in insulin-stimulated docking of GSVs to the PM in 3T3-L1 adipocytes through SNARE complex formation.« less

21 CFR 884.1720 - Gynecologic laparoscope and accessories.

Code of Federal Regulations, 2013 CFR

2013-04-01

... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...), retractor, mechanical (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable...

21 CFR 884.1720 - Gynecologic laparoscope and accessories.

Code of Federal Regulations, 2014 CFR

2014-04-01

... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...), retractor, mechanical (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable...

21 CFR 884.1720 - Gynecologic laparoscope and accessories.

Code of Federal Regulations, 2012 CFR

2012-04-01

... accessory instruments include: the lens cleaning brush, biopsy brush, clip applier (without clips...), retractor, mechanical (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable...

Tree-ring reconstruction of streamflow in the Snare River Basin, Northwest Territories, Canada

NASA Astrophysics Data System (ADS)

Martin, J. P.; Pisaric, M. F.

2017-12-01

Drought is a component of many ecosystems in North America causing environmental and socioeconomical impacts. In the ongoing context of climatic and environmental changes, drought-related issues are becoming problematic in northern Canada, which have not been associated with drought-like conditions in the past. Dryer than average conditions threatens the energy security of northern canadian communities, since this region relies on the production of hydroelectricity as an energy source. In the North Slave Region of Northwest Territory (NWT), water levels and streamflows were significantly lower in 2014/2015. The Government of the NWT had to spend nearly $50 million to purchase diesel fuel to generate enough electricity to supplement the reduced power generation of the Snare River hydroelectric system, hence the need to better understand the multi-decadal variability in streamflow. The aims of this presentation are i) to present jack pine and white spruce tree-ring chronologies of Southern NWT; ii) to reconstruct past streamflow of the Snare River Basin; iii) to evaluate the frequency and magnitude of extreme drought conditions, and iv) to identify which large-scale atmospheric or oceanic patterns are teleconnected to regional hydraulic conditions. Preliminary results show that the growth of jack pine and white spruce populations is better correlated with precipitation and temperature, respectively, than hydraulic conditions. Nonetheless, we present a robust streamflow reconstruction of the Snare River that is well correlated with the summer North Atlantic Oscillation (NAO) index, albeit the strength of the correlation is non-stationary. Spectral analysis corroborate the synchronicity between negative NAO conditions and drought conditions. From an operational standpoint, considering that the general occurrence of positive/negative NAO can be predicted, it the hope of the authors that these results can facilitate energetic planning in the Northwest Territories through the assessment of the prevailing streamflow scenario.

Histological Comparison of Cold versus Hot Snare Resections of the Colorectal Mucosa.

PubMed

Takayanagi, Daisuke; Nemoto, Daiki; Isohata, Noriyuki; Endo, Shungo; Aizawa, Masato; Utano, Kenichi; Kumamoto, Kensuke; Hojo, Hiroshi; Lefor, Alan Kawarai; Togashi, Kazutomo

2018-06-25

Delayed postpolypectomy bleeding occurs more frequently after hot resection than after cold resection. To elucidate the underlying mechanism, we performed a histological comparison of tissue after cold and hot snare resections. This is a prospective study, registered in the University Hospital Medical Information Network (UMIN000020104). This study was conducted at Aizu Medical Center, Fukushima Medical University, Japan. Fifteen patients scheduled to undergo resection of colorectal cancer were enrolled. On the day before surgery, 2 mucosal resections (hot and cold) of normal mucosa were performed on each patient using the same snare without saline injection. The difference was only the application of electrocautery or not. Resection sites were placed close to the cancer to be included in the surgical specimen. The primary outcome measure was the depth of destruction. Secondary outcome measures included the width of destruction, depth of the remaining submucosa, and number of vessels remaining at the resection sites. The number and diameter of vessels in undamaged submucosa were also evaluated. All cold resections were limited to the shallow submucosa, whereas 60% of hot resections advanced to the deep submucosa and 20% to the muscularis propria (p < 0.001). There was no significant difference in the width of destruction. The number of remaining large vessels after hot resections trended toward fewer (p = 0.15) with a decreased depth of remaining submucosa (p = 0.007). In the deep submucosa, the vessel diameter was larger (p < 0.001) and the number of large vessels was greater (p = 0.018). Histological assessment was not blinded to the 2 reviewers. Normal mucosa was used instead of adenomatous tissue. Hot resection caused damage to deeper layers involving more large vessels. This may explain the mechanism for the reduced incidence of hemorrhage after cold snare polypectomy. See Video Abstract at http://links.lww.com/DCR/A631.

21 CFR 884.1640 - Culdoscope and accessories.

Code of Federal Regulations, 2014 CFR

2014-04-01

... instruments include: lens cleaning brush, biopsy brush, clip applier (without clips), applicator, cannula... (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable) scissors, and suction/irrigation...

21 CFR 884.1640 - Culdoscope and accessories.

Code of Federal Regulations, 2012 CFR

2012-04-01

... instruments include: lens cleaning brush, biopsy brush, clip applier (without clips), applicator, cannula... (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable) scissors, and suction/irrigation...

21 CFR 884.1640 - Culdoscope and accessories.

Code of Federal Regulations, 2013 CFR

2013-04-01

... instruments include: lens cleaning brush, biopsy brush, clip applier (without clips), applicator, cannula... (noninflatable), snare, stylet, forceps, dissector, mechanical (noninflatable) scissors, and suction/irrigation...

Percutaneous closure of a giant left ventricular wall pseudoaneurysm: Anterograde approach with a double snare technique.

PubMed

Afonso Nogueira, Marta; Fiarresga, António; de Sousa, Lídia; Agapito, Ana; Galrinho, Ana; Cruz Ferreira, Rui

2016-01-01

Left ventricular pseudoaneurysm is a rare complication of acute myocardial infarction, cardiac surgery, trauma or infection. Since surgical repair is associated with high morbidity and mortality, percutaneous closure has been described as an alternative. In this regard, we present a case in which a symptomatic large left ventricular pseudoaneurysm was treated by percutaneous closure due to the patient's high surgical risk, using a double snare technique. Despite the technical difficulties, this procedure had a good final result followed by clinical success, confirming that this procedure is an effective alternative to surgery in high-risk patients. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Selected SNARE proteins are essential for the polarized membrane insertion of igf-1 receptor and the regulation of initial axonal outgrowth in neurons.

PubMed

Grassi, Diego; Plonka, Florentyna Bustos; Oksdath, Mariana; Guil, Alvaro Nieto; Sosa, Lucas J; Quiroga, Santiago

2015-01-01

The establishment of polarity necessitates initial axonal outgrowth and, therefore, the addition of new membrane to the axon's plasmalemma. Axolemmal expansion occurs by exocytosis of plasmalemmal precursor vesicles (PPVs) primarily at the neuronal growth cone. Little is known about the SNAREs family proteins involved in the regulation of PPV fusion with the neuronal plasmalemma at early stages of differentiation. We show here that five SNARE proteins (VAMP2, VAMP4, VAMP7, Syntaxin6 and SNAP23) were expressed by hippocampal pyramidal neurons before polarization. Expression silencing of three of these proteins (VAMP4, Syntaxin6 and SNAP23) repressed axonal outgrowth and the establishment of neuronal polarity, by inhibiting IGF-1 receptor exocytotic polarized insertion, necessary for neuronal polarization. In addition, stimulation with IGF-1 triggered the association of VAMP4, Syntaxin6 and SNAP23 to vesicular structures carrying the IGF-1 receptor and overexpression of a negative dominant form of Syntaxin6 significantly inhibited exocytosis of IGF-1 receptor containing vesicles at the neuronal growth cone. Taken together, our results indicated that VAMP4, Syntaxin6 and SNAP23 functions are essential for regulation of PPV exocytosis and the polarized insertion of IGF-1 receptor and, therefore, required for initial axonal elongation and the establishment of neuronal polarity.

The life cycle of platelet granules.

PubMed

Sharda, Anish; Flaumenhaft, Robert

2018-01-01

Platelet granules are unique among secretory vesicles in both their content and their life cycle. Platelets contain three major granule types-dense granules, α-granules, and lysosomes-although other granule types have been reported. Dense granules and α-granules are the most well-studied and the most physiologically important. Platelet granules are formed in large, multilobulated cells, termed megakaryocytes, prior to transport into platelets. The biogenesis of dense granules and α-granules involves common but also distinct pathways. Both are formed from the trans -Golgi network and early endosomes and mature in multivesicular bodies, but the formation of dense granules requires trafficking machinery different from that of α-granules. Following formation in the megakaryocyte body, both granule types are transported through and mature in long proplatelet extensions prior to the release of nascent platelets into the bloodstream. Granules remain stored in circulating platelets until platelet activation triggers the exocytosis of their contents. Soluble N -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, located on both the granules and target membranes, provide the mechanical energy that enables membrane fusion during both granulogenesis and exocytosis. The function of these core fusion engines is controlled by SNARE regulators, which direct the site, timing, and extent to which these SNAREs interact and consequently the resulting membrane fusion. In this review, we assess new developments in the study of platelet granules, from their generation to their exocytosis.

Selective expression of a sec1/munc18 member in sea urchin eggs and embryos.

PubMed

Leguia, Mariana; Wessel, Gary M

2004-10-01

Regulated secretion is mediated by SNAREs (soluble NSF attachment receptors) and their regulators and effectors, which include the SM (sec1/munc18) family of proteins. Homologs of the SNAREs have been identified in sea urchins, associated with cortical granule exocytosis at fertilization, with membranes of the cleavage furrow, and in secretory cells later in development. To contribute to the understanding of regulated secretion in sea urchins we have cloned the single SM protein homolog from two species of sea urchin, Lytechinus variegatus and Strongylocentrotus purpuratus. In oocytes and eggs, we find that it localizes to the plasma membrane and the cortical region of the egg, consistent with a role in one of the steps leading to cortical granule exocytosis. The protein is also expressed throughout development, enriched in membranes of the cleavage furrow in early embryos, and in cells of the gut in advanced embryos. Furthermore, we find that sec1/munc18 co-localizes with its cognate binding partner syntaxin. Finally, our biochemical analysis shows that the protein associates with rab3 in high molecular weight complexes, suggesting that the exocytotic machinery functions as a multi-protein subunit to mediate regulated secretion in sea urchins. These results will be instrumental in the future to functionally test the SNARE regulators associated with multiple membrane fusion events.

Selective Regulation of Maize Plasma Membrane Aquaporin Trafficking and Activity by the SNARE SYP121[W

PubMed Central

Besserer, Arnaud; Burnotte, Emeline; Bienert, Gerd Patrick; Chevalier, Adrien S.; Errachid, Abdelmounaim; Grefen, Christopher; Blatt, Michael R.; Chaumont, François

2012-01-01

Plasma membrane intrinsic proteins (PIPs) are aquaporins facilitating the diffusion of water through the cell membrane. We previously showed that the traffic of the maize (Zea mays) PIP2;5 to the plasma membrane is dependent on the endoplasmic reticulum diacidic export motif. Here, we report that the post-Golgi traffic and water channel activity of PIP2;5 are regulated by the SNARE (for soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) SYP121, a plasma membrane resident syntaxin involved in vesicle traffic, signaling, and regulation of K+ channels. We demonstrate that the expression of the dominant-negative SYP121-Sp2 fragment in maize mesophyll protoplasts or epidermal cells leads to a decrease in the delivery of PIP2;5 to the plasma membrane. Protoplast and oocyte swelling assays showed that PIP2;5 water channel activity is negatively affected by SYP121-Sp2. A combination of in vitro (copurification assays) and in vivo (bimolecular fluorescence complementation, Förster resonance energy transfer, and yeast split-ubiquitin) approaches allowed us to demonstrate that SYP121 and PIP2;5 physically interact. Together with previous data demonstrating the role of SYP121 in regulating K+ channel trafficking and activity, these results suggest that SYP121 SNARE contributes to the regulation of the cell osmotic homeostasis. PMID:22942383

Selective regulation of maize plasma membrane aquaporin trafficking and activity by the SNARE SYP121.

PubMed

Besserer, Arnaud; Burnotte, Emeline; Bienert, Gerd Patrick; Chevalier, Adrien S; Errachid, Abdelmounaim; Grefen, Christopher; Blatt, Michael R; Chaumont, François

2012-08-01

Plasma membrane intrinsic proteins (PIPs) are aquaporins facilitating the diffusion of water through the cell membrane. We previously showed that the traffic of the maize (Zea mays) PIP2;5 to the plasma membrane is dependent on the endoplasmic reticulum diacidic export motif. Here, we report that the post-Golgi traffic and water channel activity of PIP2;5 are regulated by the SNARE (for soluble N-ethylmaleimide-sensitive factor protein attachment protein receptor) SYP121, a plasma membrane resident syntaxin involved in vesicle traffic, signaling, and regulation of K(+) channels. We demonstrate that the expression of the dominant-negative SYP121-Sp2 fragment in maize mesophyll protoplasts or epidermal cells leads to a decrease in the delivery of PIP2;5 to the plasma membrane. Protoplast and oocyte swelling assays showed that PIP2;5 water channel activity is negatively affected by SYP121-Sp2. A combination of in vitro (copurification assays) and in vivo (bimolecular fluorescence complementation, Förster resonance energy transfer, and yeast split-ubiquitin) approaches allowed us to demonstrate that SYP121 and PIP2;5 physically interact. Together with previous data demonstrating the role of SYP121 in regulating K(+) channel trafficking and activity, these results suggest that SYP121 SNARE contributes to the regulation of the cell osmotic homeostasis.

Dynamical Organization of Syntaxin-1A at the Presynaptic Active Zone

PubMed Central

Ullrich, Alexander; Böhme, Mathias A.; Schöneberg, Johannes; Depner, Harald; Sigrist, Stephan J.; Noé, Frank

2015-01-01

Synaptic vesicle fusion is mediated by SNARE proteins forming in between synaptic vesicle (v-SNARE) and plasma membrane (t-SNARE), one of which is Syntaxin-1A. Although exocytosis mainly occurs at active zones, Syntaxin-1A appears to cover the entire neuronal membrane. By using STED super-resolution light microscopy and image analysis of Drosophila neuro-muscular junctions, we show that Syntaxin-1A clusters are more abundant and have an increased size at active zones. A computational particle-based model of syntaxin cluster formation and dynamics is developed. The model is parametrized to reproduce Syntaxin cluster-size distributions found by STED analysis, and successfully reproduces existing FRAP results. The model shows that the neuronal membrane is adjusted in a way to strike a balance between having most syntaxins stored in large clusters, while still keeping a mobile fraction of syntaxins free or in small clusters that can efficiently search the membrane or be traded between clusters. This balance is subtle and can be shifted toward almost no clustering and almost complete clustering by modifying the syntaxin interaction energy on the order of only 1 kBT. This capability appears to be exploited at active zones. The larger active-zone syntaxin clusters are more stable and provide regions of high docking and fusion capability, whereas the smaller clusters outside may serve as flexible reserve pool or sites of spontaneous ectopic release. PMID:26367029

21 CFR 876.4730 - Manual gastroenterology-urology surgical instrument and accessories.

Code of Federal Regulations, 2013 CFR

2013-04-01

... forceps cover, biopsy tray without biopsy instruments, line clamp, nonpowered rectal probe, nonelectrical..., gastro-urology probe and director, nonself-retaining retractor, laparotomy rings, nonelectrical snare...

21 CFR 876.4730 - Manual gastroenterology-urology surgical instrument and accessories.

Code of Federal Regulations, 2012 CFR

2012-04-01

... forceps cover, biopsy tray without biopsy instruments, line clamp, nonpowered rectal probe, nonelectrical..., gastro-urology probe and director, nonself-retaining retractor, laparotomy rings, nonelectrical snare...

21 CFR 876.4730 - Manual gastroenterology-urology surgical instrument and accessories.

Code of Federal Regulations, 2014 CFR

2014-04-01

... forceps cover, biopsy tray without biopsy instruments, line clamp, nonpowered rectal probe, nonelectrical..., gastro-urology probe and director, nonself-retaining retractor, laparotomy rings, nonelectrical snare...

21 CFR 876.4730 - Manual gastroenterology-urology surgical instrument and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... forceps cover, biopsy tray without biopsy instruments, line clamp, nonpowered rectal probe, nonelectrical..., gastro-urology probe and director, nonself-retaining retractor, laparotomy rings, nonelectrical snare...

21 CFR 876.4730 - Manual gastroenterology-urology surgical instrument and accessories.

Code of Federal Regulations, 2011 CFR

2011-04-01

... forceps cover, biopsy tray without biopsy instruments, line clamp, nonpowered rectal probe, nonelectrical..., gastro-urology probe and director, nonself-retaining retractor, laparotomy rings, nonelectrical snare...

Conformational fluctuation of Synaptotagmin-1 observed with single molecule fluorescence resonance energy transfer (smFRET)

NASA Astrophysics Data System (ADS)

Choi, Ucheor; Weninger, Keith

2008-10-01

Calcium dependent neurotransmitter release at the synapses involves a synaptic vesicle protein synaptotagmin-1, a calcium sensor, to regulate exocytosis. It has been known that Synaptotagmin-1 interacts with assembled SNARE complexes, but it is unclear how their molecular mechanisms are coupled. X-ray studies in the absence of calcium revealed a closed conformation of synaptotagmin-1 and with calcium bound to the C2 domains of synaptotagmin-3 found extensive interactions holding the domains open. Suggesting the two conformations can be the key to the two functions of synaptotagmin in regulating neurotransmission. Here we use single molecule fluorescence resonance energy transfer (smFRET) to study synaptotagmin interactions with SNARE complexes and the spontaneous conformational changes of synaptotagmin-1 when calcium is induced.

Expression and subcellular localization of the Qa-SNARE syntaxin17 in human eosinophils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmo, Lívia A.S.; Dias, Felipe F.; Malta, Kássia K.

Background: SNARE members mediate membrane fusion during intracellular trafficking underlying innate and adaptive immune responses by different cells. However, little is known about the expression and function of these proteins in human eosinophils, cells involved in allergic, inflammatory and immunoregulatory responses. Here, we investigate the expression and distribution of the Qa-SNARE syntaxin17 (STX17) within human eosinophils isolated from the peripheral blood. Methods: Flow cytometry and a pre-embedding immunonanogold electron microscopy (EM) technique that combines optimal epitope preservation and secondary Fab-fragments of antibodies linked to 1.4 nm gold particles for optimal access to microdomains, were used to investigate STX17. Results: STX17more » was detected within unstimulated eosinophils. Immunogold EM revealed STX17 on secretory granules and on granule-derived vesiculotubular transport carriers (Eosinophil Sombrero Vesicles-EoSVs). Quantitative EM analyses showed that 77.7% of the granules were positive for STX17 with a mean±SEM of 3.9±0.2 gold particles/granule. Labeling was present on both granule outer membranes and matrices while EoSVs showed clear membrane-associated labeling. STX17 was also present in secretory granules in eosinophils stimulated with the cytokine tumor necrosis factor alpha (TNF-α) or the CC-chemokine ligand 11 CCL11 (eotaxin-1), stimuli that induce eosinophil degranulation. The number of secretory granules labeled for STX17 was significantly higher in CCL11 compared with the unstimulated group. The level of cell labeling did not change when unstimulated cells were compared with TNF-α-stimulated eosinophils. Conclusions: The present study clearly shows by immunanonogold EM that STX17 is localized in eosinophil secretory granules and transport vesicles and might be involved in the transport of granule-derived cargos. - Highlights: • First demonstration of the Qa-SNARE syntaxin-17 (STX17) in human eosinophils. • High resolution immunogold EM shows STX17 in granules and tubular vesicles. • Unstimulated, TNF-α or CCL11-stimulated eosinophils express STX17. • Our findings suggest a role for STX17 in the transport of granule-derived cargos.« less

Transarterial Embolization of a Renal Artery Aneurysm Concomitant With Renal Arteriovenous Fistula.

PubMed

Hongsakul, Keerati; Bannangkoon, Kittipitch; Boonsrirat, Ussanee; Kritpracha, Boonprasit

2018-01-01

Congenital renal artery aneurysm is uncommon. Moreover, renal artery aneurysm concomitant with a congenital renal arteriovenous fistula is extremely rare. Transarterial embolization is the first-line treatment for these conditions. We report a case of a patient with congenital renal artery aneurysm concomitant with a congenital renal arteriovenous fistula of the upper polar left renal artery which was successfully treated by transarterial embolization with coil, glue, and Amplatzer vascular plug.

Hydrophobic mismatch sorts SNARE proteins into distinct membrane domains

PubMed Central

Milovanovic, Dragomir; Honigmann, Alf; Koike, Seiichi; Göttfert, Fabian; Pähler, Gesa; Junius, Meike; Müllar, Stefan; Diederichsen, Ulf; Janshoff, Andreas; Grubmüller, Helmut; Risselada, Herre J.; Eggeling, Christian; Hell, Stefan W.; van den Bogaart, Geert; Jahn, Reinhard

2015-01-01

The clustering of proteins and lipids in distinct microdomains is emerging as an important principle for the spatial patterning of biological membranes. Such domain formation can be the result of hydrophobic and ionic interactions with membrane lipids as well as of specific protein–protein interactions. Here using plasma membrane-resident SNARE proteins as model, we show that hydrophobic mismatch between the length of transmembrane domains (TMDs) and the thickness of the lipid membrane suffices to induce clustering of proteins. Even when the TMDs differ in length by only a single residue, hydrophobic mismatch can segregate structurally closely homologous membrane proteins in distinct membrane domains. Domain formation is further fine-tuned by interactions with polyanionic phosphoinositides and homo and heterotypic protein interactions. Our findings demonstrate that hydrophobic mismatch contributes to the structural organization of membranes. PMID:25635869

Mechanical Coupling via the Membrane Fusion SNARE Protein Syntaxin 1A: A Molecular Dynamics Study

PubMed Central

Knecht, Volker; Grubmüller, Helmut

2003-01-01

SNARE trans complexes between membranes likely promote membrane fusion. For the t-SNARE syntaxin 1A involved in synaptic transmission, the secondary structure and bending stiffness of the five-residue juxtamembrane linker is assumed to determine the required mechanical energy transfer from the cytosolic core complex to the membrane. These properties have here been studied by molecular dynamics and annealing simulations for the wild-type and a C-terminal-prolongated mutant within a neutral and an acidic bilayer, suggesting linker stiffnesses above 1.7 but below 50 × 10−3 kcal mol−1 deg−2. The transmembrane helix was found to be tilted by 15° and tightly anchored within the membrane with a stiffness of 4–5 kcal mol−1 Å−2. The linker turned out to be marginally helical and strongly influenced by its lipid environment. Charged lipids increased the helicity and H3 helix tilt stiffness. For the wild type, the linker was seen embedded deeply within the polar region of the bilayer, whereas the prolongation shifted the linker outward. This reduced its helicity and increased its average tilt, thereby presumably reducing fusion efficiency. Our results suggest that partially unstructured linkers provide considerable mechanical coupling; the energy transduced cooperatively by the linkers in a native fusion event is thus estimated to be 3–8 kcal/mol, implying a two-to-five orders of magnitude fusion rate increase. PMID:12609859

Myosins and DYNLL1/LC8 in the honey bee (Apis mellifera L.) brain.

PubMed

Calábria, Luciana Karen; Peixoto, Pablo Marco Veras; Passos Lima, Andreia Barcelos; Peixoto, Leonardo Gomes; de Moraes, Viviane Rodrigues Alves; Teixeira, Renata Roland; Dos Santos, Claudia Tavares; E Silva, Letícia Oliveira; da Silva, Maria de Fátima Rodrigues; dos Santos, Ana Alice Diniz; Garcia-Cairasco, Norberto; Martins, Antônio Roberto; Espreafico, Enilza Maria; Espindola, Foued Salmen

2011-09-01

Honey bees have brain structures with specialized and developed systems of communication that account for memory, learning capacity and behavioral organization with a set of genes homologous to vertebrate genes. Many microtubule- and actin-based molecular motors are involved in axonal/dendritic transport. Myosin-Va is present in the honey bee Apis mellifera nervous system of the larvae and adult castes and subcastes. DYNLL1/LC8 and myosin-IIb, -VI and -IXb have also been detected in the adult brain. SNARE proteins, such as CaMKII, clathrin, syntaxin, SNAP25, munc18, synaptophysin and synaptotagmin, are also expressed in the honey bee brain. Honey bee myosin-Va displayed ATP-dependent solubility and was associated with DYNLL1/LC8 and SNARE proteins in the membrane vesicle-enriched fraction. Myosin-Va expression was also decreased after the intracerebral injection of melittin and NMDA. The immunolocalization of myosin-Va and -IV, DYNLL1/LC8, and synaptophysin in mushroom bodies, and optical and antennal lobes was compared with the brain morphology based on Neo-Timm histochemistry and revealed a distinct and punctate distribution. This result suggested that the pattern of localization is associated with neuron function. Therefore, our data indicated that the roles of myosins, DYNLL1/LC8, and SNARE proteins in the nervous and visual systems of honey bees should be further studied under different developmental, caste and behavioral conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Phosphorylation of SNAP-23 at Ser95 causes a structural alteration and negatively regulates Fc receptor-mediated phagosome formation and maturation in macrophages.

PubMed

Sakurai, Chiye; Itakura, Makoto; Kinoshita, Daiki; Arai, Seisuke; Hashimoto, Hitoshi; Wada, Ikuo; Hatsuzawa, Kiyotaka

2018-05-17

SNAP-23 is a plasma membrane-localized SNARE protein involved in Fc receptor (FcR)-mediated phagocytosis. However, the regulatory mechanism underlying its function remains elusive. Using phosphorylation specific-antibodies, SNAP-23 was found to be phosphorylated at Ser95 in macrophages. To understand the role of this phosphorylation, we established macrophage lines overexpressing the non-phosphorylatable S95A or the phospho-mimicking S95D mutation. The efficiency of phagosome formation and maturation was severely reduced in SNAP-23-S95D-overexpressing cells. To examine whether phosphorylation at Ser95 affected SNAP-23 structure, we constructed intramolecular Förster resonance energy transfer (FRET) probes of SNAP-23 designed to evaluate the approximation of the N-termini of the two SNARE motifs. Interestingly, a high FRET efficiency was detected on the membrane when the S95D probe was used, indicating that phosphorylation at Ser95 caused a dynamic structural shift to the closed form. Co-expression of IκB kinase (IKK) 2 enhanced the FRET efficiency of the wild-type probe on the phagosome membrane. Furthermore, the enhanced phagosomal FRET signal in interferon-γ-activated macrophages was largely dependent on IKK2, and this kinase mediated a delay in phagosome-lysosome fusion. These results suggested that SNAP-23 phosphorylation at Ser95 played an important role in the regulation of SNARE-dependent membrane fusion during FcR-mediated phagocytosis.

Munc13-4 functions as a Ca2+ sensor for homotypic secretory granule fusion to generate endosomal exocytic vacuoles

PubMed Central

Woo, Sang Su; James, Declan J.; Martin, Thomas F. J.

2017-01-01

Munc13-4 is a Ca2+-dependent SNARE (soluble N-ethylmaleimide–sensitive factor attachment protein receptor)- and phospholipid-binding protein that localizes to and primes secretory granules (SGs) for Ca2+-evoked secretion in various secretory cells. Studies in mast cell–like RBL-2H3 cells provide direct evidence that Munc13–4 with its two Ca2+-binding C2 domains functions as a Ca2+ sensor for SG exocytosis. Unexpectedly, Ca2+ stimulation also generated large (>2.4 μm in diameter) Munc13-4+/Rab7+/Rab11+ endosomal vacuoles. Vacuole generation involved the homotypic fusion of Munc13-4+/Rab7+ SGs, followed by a merge with Rab11+ endosomes, and depended on Ca2+ binding to Munc13-4. Munc13-4 promoted the Ca2+-stimulated fusion of VAMP8-containing liposomes with liposomes containing exocytic or endosomal Q-SNAREs and directly interacted with late endosomal SNARE complexes. Thus Munc13-4 is a tethering/priming factor and Ca2+ sensor for both heterotypic SG-plasma membrane and homotypic SG-SG fusion. Total internal reflection fluorescence microscopy imaging revealed that vacuoles were exocytic and mediated secretion of β-hexosaminidase and cytokines accompanied by Munc13-4 diffusion onto the plasma membrane. The results provide new molecular insights into the mechanism of multigranular compound exocytosis commonly observed in various secretory cells. PMID:28100639

Congenital intrahepatic portosystemic shunts: Imaging findings and endovascular management

PubMed Central

Chandrasekharan, Rajsekar; Pullara, Sreekumar K; Thomas, Tixon; Kader, Nazar Puthukudiyil; Moorthy, Srikanth

2016-01-01

We present two cases of congenital intrahepatic portosystemic shunts in which the right portal vein directly communicated with the inferior venacava (IVC) in one patient and with the hepatic vein in the other. Multiple hepatic nodules consistent with focal nodular hyperplasia (FNH) were seen in the first patient. The second patient presented with recurrent history of hepatic encephalopathy. Percutaneous transhepatic embolization was performed using coils and Amplatz device following which she completely recovered. PMID:27081230

Applications of the Amplatzer Vascular Plug to various vascular lesions

PubMed Central

Güneyli, Serkan; Çınar, Celal; Bozkaya, Halil; Parıldar, Mustafa; Oran, İsmail

2014-01-01

The Amplatzer® Vascular Plug (AVP) can be used to embolize medium-to-large high-flow vessels in various locations. Between 2009 and 2012, 41 AVPs (device size, 6–22 mm in diameter) were used to achieve occlusion in 31 patients (24 males, seven females) aged 9–92 years (mean age, 54.5 years). The locations and indications for embolotherapy were as follows: internal iliac artery embolization before stent-graft repair for aorto-iliac (n=6) and common iliac artery (n=3) aneurysms, subclavian artery embolization before stent-graft repair for thoracic aorta (n=3) and arcus aorta (n=1) aneurysms, brachiocephalic trunk embolization before stent-graft repair for a thoracic aorta aneurysm (n=1), embolization of aneurysms and pseudoaneurysms (n=5), embolization for carotid blow-out syndrome (n=3), closure of arteriovenous fistula (n=8), and closure of a portosystemic fistula (n=1). Of the 41 AVPs, 30 were AVP 2 and 11 were AVP 4. The mean follow-up duration was 4.7 months (range, 1–24 months). During follow-up, there was one migration, one insufficient embolization, and one recanalization. The remaining vascular lesions were successfully excluded from the circulation. The AVP, which can be used in a wide spectrum of pathologies, is easy to use and causes few complications. This essay presents our experience with the AVP. PMID:24047719

21 CFR 876.4300 - Endoscopic electrosurgical unit and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Endoscopic electrosurgical unit and accessories. (a) Identification. An endoscopic electrosurgical unit and... device includes the electrosurgical generator, patient plate, electric biopsy forceps, electrode, flexible snare, electrosurgical alarm system, electrosurgical power supply unit, electrical clamp, self...

Combined use of clips and nylon snare ("tulip-bundle") as a rescue endoscopic bleeding control in a mallory-weiss syndrome.

PubMed

Ivekovic, Hrvoje; Radulovic, Bojana; Jankovic, Suzana; Markos, Pave; Rustemovic, Nadan

2014-01-01

Mallory-Weiss syndrome (MWS) accounts for 6-14% of all cases of upper gastrointestinal bleeding. Prognosis of patients with MWS is generally good, with a benign course and rare recurrence of bleeding. However, no strict recommendations exist in regard to the mode of action after a failure of primary endoscopic hemostasis. We report a case of an 83-year-old male with MWS and rebleeding after the initial endoscopic treatment with epinephrine and clips. The final endoscopic control of bleeding was achieved by a combined application of clips and a nylon snare in a "tulip-bundle" fashion. The patient had an uneventful postprocedural clinical course and was discharged from the hospital five days later. To the best of our knowledge, this is the first case report showing the "tulip-bundle" technique as a rescue endoscopic bleeding control in the esophagus.

Retrograde traffic from the Golgi to the endoplasmic reticulum.

PubMed

Spang, Anne

2013-06-01

Proteins to be secreted are transported from the endoplasmic reticulum (ER) to the Golgi apparatus. The transport of these proteins requires the localization and activity of proteins that create ER exit sites, coat proteins to collect cargo and to reshape the membrane into a transport container, and address labels--SNARE proteins--to target the vesicles specifically to the Golgi apparatus. In addition some proteins may need export chaperones or export receptors to enable their exit into transport vesicles. ER export factors, SNAREs, and misfolded Golgi-resident proteins must all be retrieved from the Golgi to the ER again. This retrieval is also part of the organellar homeostasis pathway essential to maintaining the identity of the ER and of the Golgi apparatus. In this review, I will discuss the different processes in retrograde transport from the Golgi to the ER and highlight the mechanistic insights we have obtained in the last couple of years.

Retrograde Traffic from the Golgi to the Endoplasmic Reticulum

PubMed Central

Spang, Anne

2013-01-01

Proteins to be secreted are transported from the endoplasmic reticulum (ER) to the Golgi apparatus. The transport of these proteins requires the localization and activity of proteins that create ER exit sites, coat proteins to collect cargo and to reshape the membrane into a transport container, and address labels—SNARE proteins—to target the vesicles specifically to the Golgi apparatus. In addition some proteins may need export chaperones or export receptors to enable their exit into transport vesicles. ER export factors, SNAREs, and misfolded Golgi-resident proteins must all be retrieved from the Golgi to the ER again. This retrieval is also part of the organellar homeostasis pathway essential to maintaining the identity of the ER and of the Golgi apparatus. In this review, I will discuss the different processes in retrograde transport from the Golgi to the ER and highlight the mechanistic insights we have obtained in the last couple of years. PMID:23732476

Molecular Mechanisms for the Coupling of Endocytosis to Exocytosis in Neurons

PubMed Central

Xie, Zhenli; Long, Jiangang; Liu, Jiankang; Chai, Zuying; Kang, Xinjiang; Wang, Changhe

2017-01-01

Neuronal communication and brain function mainly depend on the fundamental biological events of neurotransmission, including the exocytosis of presynaptic vesicles (SVs) for neurotransmitter release and the subsequent endocytosis for SV retrieval. Neurotransmitters are released through the Ca2+- and SNARE-dependent fusion of SVs with the presynaptic plasma membrane. Following exocytosis, endocytosis occurs immediately to retrieve SV membrane and fusion machinery for local recycling and thus maintain the homeostasis of synaptic structure and sustained neurotransmission. Apart from the general endocytic machinery, recent studies have also revealed the involvement of SNARE proteins (synaptobrevin, SNAP25 and syntaxin), synaptophysin, Ca2+/calmodulin, and members of the synaptotagmin protein family (Syt1, Syt4, Syt7 and Syt11) in the balance and tight coupling of exo-endocytosis in neurons. Here, we provide an overview of recent progress in understanding how these neuron-specific adaptors coordinate to ensure precise and efficient endocytosis during neurotransmission. PMID:28348516

Gastric Bezoar Treatment by Endoscopic Fragmentation in Combination with Pepsi-Cola® Administration.

PubMed

Iwamuro, Masaya; Yunoki, Naoko; Tomoda, Jun; Nakamura, Kazuhiro; Okada, Hiroyuki; Yamamoto, Kazuhide

2015-07-10

Although bezoar dissolution by Coca-Cola® has been described in case reports and case series, to the best of our knowledge, the usefulness of other cola products such as Pepsi-Cola® has never been reported in the English literature. An 86-year-old Taiwanese man was diagnosed with a gastric bezoar. Endoscopic fragmentation with a polypectomy snare was attempted twice but failed to remove the bezoar. Subsequently, 500 mL of Pepsi NEX Zero® was administered daily for 4 days via nasogastric tube. The bezoar was softened and successfully fragmented by the polypectomy snare and needle-knife devices on the third attempt. This report presents the first case of a gastric bezoar successfully treated by endoscopic fragmentation in combination with Pepsi-Cola® administration, suggesting the possible utility of cola beverages in bezoar treatment, regardless of product brands.

Adaptive evolution of sexual systems in pedunculate barnacles

PubMed Central

Yusa, Yoichi; Yoshikawa, Mai; Kitaura, Jun; Kawane, Masako; Ozaki, Yuki; Yamato, Shigeyuki; Høeg, Jens T.

2012-01-01

How and why diverse sexual systems evolve are fascinating evolutionary questions, but few empirical studies have dealt with these questions in animals. Pedunculate (gooseneck) barnacles show such diversity, including simultaneous hermaphroditism, coexistence of dwarf males and hermaphrodites (androdioecy), and coexistence of dwarf males and females (dioecy). Here, we report the first phylogenetically controlled test of the hypothesis that the ultimate cause of the diverse sexual systems and presence of dwarf males in this group is limited mating opportunities for non-dwarf individuals, owing to mating in small groups. Within the pedunculate barnacle phylogeny, dwarf males and females have evolved repeatedly. Females are more likely to evolve in androdioecious than hermaphroditic populations, suggesting that evolution of dwarf males has preceded that of females in pedunculates. Both dwarf males and females are associated with a higher proportion of solitary individuals in the population, corroborating the hypothesis that limited mating opportunities have favoured evolution of these diverse sexual systems, which have puzzled biologists since Darwin. PMID:21881138

2BC Non-Structural Protein of Enterovirus A71 Interacts with SNARE Proteins to Trigger Autolysosome Formation.

PubMed

Lai, Jeffrey K F; Sam, I-Ching; Verlhac, Pauline; Baguet, Joël; Eskelinen, Eeva-Liisa; Faure, Mathias; Chan, Yoke Fun

2017-07-04

Viruses have evolved unique strategies to evade or subvert autophagy machinery. Enterovirus A71 (EV-A71) induces autophagy during infection in vitro and in vivo. In this study, we report that EV-A71 triggers autolysosome formation during infection in human rhabdomyosarcoma (RD) cells to facilitate its replication. Blocking autophagosome-lysosome fusion with chloroquine inhibited virus RNA replication, resulting in lower viral titres, viral RNA copies and viral proteins. Overexpression of the non-structural protein 2BC of EV-A71 induced autolysosome formation. Yeast 2-hybrid and co-affinity purification assays showed that 2BC physically and specifically interacted with a N -ethylmaleimide-sensitive factor attachment receptor (SNARE) protein, syntaxin-17 (STX17). Co-immunoprecipitation assay further showed that 2BC binds to SNARE proteins, STX17 and synaptosome associated protein 29 (SNAP29). Transient knockdown of STX17, SNAP29, and microtubule-associated protein 1 light chain 3B (LC3B), crucial proteins in the fusion between autophagosomes and lysosomes) as well as the lysosomal-associated membrane protein 1 (LAMP1) impaired production of infectious EV-A71 in RD cells. Collectively, these results demonstrate that the generation of autolysosomes triggered by the 2BC non-structural protein is important for EV-A71 replication, revealing a potential molecular pathway targeted by the virus to exploit autophagy. This study opens the possibility for the development of novel antivirals that specifically target 2BC to inhibit formation of autolysosomes during EV-A71 infection.

Amyloplast movement and gravityperception in Arabidopsis endoderm

NASA Astrophysics Data System (ADS)

Tasaka, M.; Saito, T.; Morita, M. T.

Gravitropism of higher plant is a growth response regulating the orientation of organs elongation, which includes four sequential steps, the perception of gravistimulus, transduction of the physical stimulus to chemical signal, transmission of the signal, and differential cell elongation depending on the signal. To elucidate the molecular mechanism of these steps, we have isolated a number of Arabidopsis mutants with abnormal shoot gravitropic response. zig (zigzag)/sgr4(shoot gravitropism 4) shows little gravitropism in their shoots. Besides, their inflorescence stems elongate in a zigzag-fashion to bend at each node. ZIG encodes a SNARE, AtVTI11. sgr3 with reduced gravitropic response in inflorescence stems had a missense mutation in other SNARE, AtVAM3. These two SNAREs make a complex in the shoot endoderm cells that are gravity-sensing cells, suggesting that the vesicle transport from trans-Golgi network (TGN) to prevacuolar compartment (PVC) and/or vacuole is involved in gravitropism. Abnormal vesicular/vacuolar structures were observed in several tissues of both mutants. Moreover, SGR2 encodes phospholipase A1-like protein that resides in the vacuolar membrane. Endodermis-specific expression of these genes could complement gravitropism in each mutant. In addition, amyloplasts thought to be statoliths localized abnormally in their endoderm cells. These results strongly suggest that formation and function of vacuole in the endoderm cells are important for amyloplasts sedimentation, which is involved in the early process of shoot gravitropism. To reveal this, we constructed vertical stage microscope system to visualize the behavior of amyloplasts and vacuolar membrane in living endodermal cells. We hope to discuss the mechanism of gravity perception after showing their movements.

Blocking dephosphorylation at Serine 120 residue in t-SNARE SNAP-23 leads to massive inhibition in exocytosis from mast cells.

PubMed

Naskar, Pieu; Naqvi, Nilofer; Puri, Niti

2018-03-01

Mast cells (MCs) respond to allergen challenge by release of pre-stored inflammatory mediators from their secretory granules, on cross-linking of Fc(epsilon) receptor I (Fc(epsilon)RI) receptors. The target-SNARE (t-SNARE) SNAP-23 has been shown to play an important role in MC exocytosis and undergoes transient phosphorylation at Serine 95 (S95) and Serine 120 (S120), concomitant with mediator release. During current study we explored the importance of transient nature of phosphorylation at S120 in MC exocytosis. A phosphomimetic SNAP-23-S120D mutant of rodent SNAP-23 was cloned into EGFP vector and its effect on the exocytosis and the mechanisms involved was studied in RBL-2H3 MC line. Secretion reporter assay with SNAP-23-S120D transfected MCs revealed a very significant inhibition of exocytosis, and reduced ruffling in response to Fc(epsilon)RI cross-linking. Further, the effect of this mutation on localization of SNAP-23 in MCs was studied. Immunofluorescence microscopy studies and membrane-cytosol fractionation of green fluorescent protein-tagged SNAP- 23-S120D (GFP-SNAP-23-S120D) transfected MCs showed that a large proportion of GFP-SNAP-23-S120D was residing in cytosol unlike wild-type SNAP-23, in resting and activated MCs and even the membrane associated portion was on internal lysosomal membranes than plasma membrane. These studies imply that dephosphorylation of S120 is important for SNAP-23 membrane association dynamics and subsequently MC degranulation.

2BC Non-Structural Protein of Enterovirus A71 Interacts with SNARE Proteins to Trigger Autolysosome Formation

PubMed Central

Lai, Jeffrey K. F.; Sam, I-Ching; Verlhac, Pauline; Baguet, Joël; Faure, Mathias

2017-01-01

Viruses have evolved unique strategies to evade or subvert autophagy machinery. Enterovirus A71 (EV-A71) induces autophagy during infection in vitro and in vivo. In this study, we report that EV-A71 triggers autolysosome formation during infection in human rhabdomyosarcoma (RD) cells to facilitate its replication. Blocking autophagosome-lysosome fusion with chloroquine inhibited virus RNA replication, resulting in lower viral titres, viral RNA copies and viral proteins. Overexpression of the non-structural protein 2BC of EV-A71 induced autolysosome formation. Yeast 2-hybrid and co-affinity purification assays showed that 2BC physically and specifically interacted with a N-ethylmaleimide-sensitive factor attachment receptor (SNARE) protein, syntaxin-17 (STX17). Co-immunoprecipitation assay further showed that 2BC binds to SNARE proteins, STX17 and synaptosome associated protein 29 (SNAP29). Transient knockdown of STX17, SNAP29, and microtubule-associated protein 1 light chain 3B (LC3B), crucial proteins in the fusion between autophagosomes and lysosomes) as well as the lysosomal-associated membrane protein 1 (LAMP1) impaired production of infectious EV-A71 in RD cells. Collectively, these results demonstrate that the generation of autolysosomes triggered by the 2BC non-structural protein is important for EV-A71 replication, revealing a potential molecular pathway targeted by the virus to exploit autophagy. This study opens the possibility for the development of novel antivirals that specifically target 2BC to inhibit formation of autolysosomes during EV-A71 infection. PMID:28677644

A technique of snaring method for fitting a prosthetic valve into the annulus.

PubMed

Nagasaka, Shigeo; Kawata, Tetsuji; Matsuta, Masahiro; Taniguchi, Shigeki

2005-01-01

Tourniquetting technique to fit a prosthetic valve (PV) into the annulus in valve replacement surgery has been previously reported. We modified the previously reported method and designed a simpler tying technique. We performed 11 aortic (AVR: including four cases for calcified aortic stenosis (AS) with a small annulus and one cases for infective endocarditis with intramuscular abscess cavity), eight mitral valve replacements (MVR), and one tricuspid valve replacement (TVR: for corrected transposition of the great arteries). A PV was implanted using 2-0 polyester mattress sutures with a pledget. Each of the two tourniquets held a suture at the bottom of the annulus and at the opposite position to fit a PV. The sutures between each snare were tied down from the bottom to the top. In MVR, after seating of a PV with two tourniquets, we could make sure that no native tissue of any preserved mitral apparatus disturbed PV leaflet motion. In calcific AS, a PV had a good fitting into the annulus because of tourniquets applied to unseated part during tying sutures. In AVR for infective endocarditis, mattress sutures supported by a Teflon pledget were placed to close the abscess cavity. After snaring on one of these sutures, we tied down the sutures, ensuring that they did not cut through the friable tissues. In TVR, we found that native leaflets interfered with PV motion after seating down the prosthesis and those leaflets were resected before tying down the sutures. Postoperative transesophageal echocardiography showed no paravalvular leakage in any patients and excellent PV functions.

SNARE-dependent upregulation of KCC2 activity following metabotropic zinc receptor (mZnR/GPR39) activation in rat cortical neurons in vitro

PubMed Central

Saadi, Robert A.; He, Kai; Hartnett, Karen A.; Kandler, Karl; Hershfinkel, Michal; Aizenman, Elias

2012-01-01

The major outward chloride transporter in neurons is the potassium chloride co-transporter 2 (KCC2), critical for maintaining an inhibitory reversal potential for GABAA receptor channels. In a recent study, we showed that Zn2+ regulates GABAA reversal potentials in the hippocampus by enhancing the activity of KCC2 via an increase in its surface expression. Zn2+ initiates this process by activating the Gq-coupled metabotropic Zn2+ receptor mZnR/GPR39. Here, we first demonstrated that mZnR/GPR39 is functional in cortical neurons in culture and then tested the hypothesis that the increase in KCC2 activity is mediated through a SNARE-dependent process. We established the presence of functional mZnR in rat cultured cortical neurons by loading cells with a Ca2+ indicator and exposing cells to Zn2+, which triggered consistent Ca2+ responses that were blocked by the Gq antagonist YM-254890, but not by the metabotropic glutamate receptor antagonist MCPG. Importantly, Zn2+ treatment under these conditions did not increase the intracellular concentrations of Zn2+ itself. We then measured KCC2 activity by monitoring both the rate and relative amount of furosemide-sensitive NH4+ influx via the co-transporter using an intracellular pH sensitive fluorescent indicator. We observed that Zn2+ pretreatment induced a Ca2+-dependent increase in KCC2 activity. The effects of Zn2+ on KCC2 activity were also observed in wild-type mouse cortical neurons in culture, but not in neurons obtained from mZnR/GPR39−/− mice, suggesting that Zn2+ acts via mZnR/GPR39 activation to upregulate KCC2 activity. We next transfected rat cortical neurons with a plasmid encoding botulinum toxin C1 (Botox C1), which cleaves the SNARE proteins syntaxin 1 and SNAP-25. Basal KCC2 activity was similar in both transfected and non-transfected neurons. Non-transfected cells, or cells transfected with marker vector alone, showed a Zn2+-dependent increase in KCC2 activity. In contrast, KCC2 activity in neurons expressing Botox C1 was unchanged by Zn2+. These results suggest that SNARE proteins are necessary for the increased activity of KCC2 following Zn2+ stimulation of mZnR/GPR39. PMID:22441041

Escaping the snare of chronological growth and launching a free curve alternative: general deviance as latent growth model.

PubMed

Wood, Phillip Karl; Jackson, Kristina M

2013-08-01

Researchers studying longitudinal relationships among multiple problem behaviors sometimes characterize autoregressive relationships across constructs as indicating "protective" or "launch" factors or as "developmental snares." These terms are used to indicate that initial or intermediary states of one problem behavior subsequently inhibit or promote some other problem behavior. Such models are contrasted with models of "general deviance" over time in which all problem behaviors are viewed as indicators of a common linear trajectory. When fit of the "general deviance" model is poor and fit of one or more autoregressive models is good, this is taken as support for the inhibitory or enhancing effect of one construct on another. In this paper, we argue that researchers consider competing models of growth before comparing deviance and time-bound models. Specifically, we propose use of the free curve slope intercept (FCSI) growth model (Meredith & Tisak, 1990) as a general model to typify change in a construct over time. The FCSI model includes, as nested special cases, several statistical models often used for prospective data, such as linear slope intercept models, repeated measures multivariate analysis of variance, various one-factor models, and hierarchical linear models. When considering models involving multiple constructs, we argue the construct of "general deviance" can be expressed as a single-trait multimethod model, permitting a characterization of the deviance construct over time without requiring restrictive assumptions about the form of growth over time. As an example, prospective assessments of problem behaviors from the Dunedin Multidisciplinary Health and Development Study (Silva & Stanton, 1996) are considered and contrasted with earlier analyses of Hussong, Curran, Moffitt, and Caspi (2008), which supported launch and snare hypotheses. For antisocial behavior, the FCSI model fit better than other models, including the linear chronometric growth curve model used by Hussong et al. For models including multiple constructs, a general deviance model involving a single trait and multimethod factors (or a corresponding hierarchical factor model) fit the data better than either the "snares" alternatives or the general deviance model previously considered by Hussong et al. Taken together, the analyses support the view that linkages and turning points cannot be contrasted with general deviance models absent additional experimental intervention or control.

Transcatheter device closure of pseudoaneurysms of the left ventricular wall: An emerging therapeutic option.

PubMed

Madan, Tarun; Juneja, Manish; Raval, Abhishek; Thakkar, Bhavesh

2016-02-01

Left ventricular pseudoaneurysm is a rare but serious complication of acute myocardial infarction and cardiac surgery. While surgical intervention is the conventional therapeutic option, transcatheter closure can be considered in selected patients with suitable morphology of the pseudoaneurysm. We report a case of successful transcatheter closure of a left ventricular pseudoaneurysm orifice and isolation of the sac using an Amplatzer septal occluder. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

Ethics Issues Snare School Leaders

ERIC Educational Resources Information Center

Borja, Rhea R.

2005-01-01

This article reports on ethics issues involving school leaders. Some superintendents have landed in murky ethical waters for their ties to for-profit companies, highlighting the temptations administrators face as industry and education increasingly intersect. Some questionable judgments by superintendents--from accepting company-paid trips to…

Coronary intervention in anomalous origin of the right coronary artery (ARCA) from the left sinus of valsalva (LSOV): a single center experience.

PubMed

Uthayakumaran, Kalaichelvan; Subban, Vijayakumar; Lakshmanan, Anitha; Pakshirajan, Balaji; Solirajaram, Ramkumar; Krishnamoorthy, Jaishankar; Janakiraman, Ezhilan; Pandurangi, Ulhas M; Kalidoss, Latchumanadhas; Sankaradas, Mullasari Ajit

2014-01-01

To assess the technical challenges in percutaneous coronary intervention of Anomalous right coronary artery arising from the left sinus of valsalva. Between year 2008 and 2012, a total of 17 patients underwent PCI for an angiographically significant lesion in the right coronary artery of an anomalous origin in the LSOV. Their procedure details such as usage of catheters, radiation time, amount of contrast used were assessed. A total of 17 patients with anomalous right coronary artery underwent PCI during the above mentioned period. 8 patients had type A origin, 3 had type B origin and the remaining 6 had type C origin. Type A origin RCA were successfully cannulated in 6 patients with Judkins left 5.0 and in 2 patients using Judkins left 4.0. Extra back up (EBU) 3.5 were doing well in 2 patients of Type B origin and the remaining one patient was successfully cannulated using Judkins left 4.0. In type C origin 4 patients had successful cannulation with Amplatz Left 1.0, 1 patient with Amplatz Left 2.0 and 1 patient with Judkins left 4.0. The mean fluoroscopic time was 20.7 min and amount of contrast used was 210 ml. PCI of anomalous RCA origin from LSOV requires appropriate guide catheter selection according to the anatomy of origin for successful cannulation and to reduce the contrast usage and radiation exposure. Copyright © 2014. Published by Elsevier B.V.

Randomized clinical trial comparing percutaneous closure of patent foramen ovale (PFO) using the Amplatzer PFO Occluder with medical treatment in patients with cryptogenic embolism (PC-Trial): rationale and design

PubMed Central

2011-01-01

Background Several studies have shown an association of cryptogenic stroke and embolism with patent foramen ovale (PFO), but the question how to prevent further events in such patients is unresolved. Options include antithrombotic treatment with warfarin or antiplatelet agents or surgical or endovascular closure of the PFO. The PC-Trial was set up to compare endovascular closure and best medical treatment for prevention of recurrent events. Methods The PC-Trial is a randomized clinical trial comparing the efficacy of percutaneous closure of the PFO using the Amplatzer PFO occluder with best medical treatment in patients with cryptogenic embolism, i.e. mostly cryptogenic stroke. Warfarin for 6 months followed by antiplatelet agents is recommended as medical treatment. Randomization is stratified according to patients age (<45 versus ≥45 years), presence of atrial septal aneurysm (ASA yes or no) and number of embolic events before randomization (one versus more than one event). Primary endpoints are death, nonfatal stroke and peripheral embolism. Discussion patients were randomized in 29 centers of Europe, Canada, and Australia. Randomization started February 2000. Enrollment of 414 patients was completed in February 2009. All patients will be followed-up longitudinally. Follow-up is maintained until the last enrolled patient is beyond 2.5 years of follow-up (expected in 2011). Trial Registration Trial listed in ClinicalTrials.gov as NCT00166257 and sponsored by AGA Medical, Plymouth, MN, USA PMID:21356042

PTPRT regulates the interaction of Syntaxin-binding protein 1 with Syntaxin 1 through dephosphorylation of specific tyrosine residue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, So-Hee; Moon, Jeonghee; Lee, Myungkyu

2013-09-13

Highlights: •PTPRT is a brain-specific, expressed, protein tyrosine phosphatase. •PTPRT regulated the interaction of Syntaxin-binding protein 1 with Syntaxin 1. •PTPRT dephosphorylated the specific tyrosine residue of Syntaxin-binding protein 1. •Dephosphorylation of Syntaxin-binding protein 1 enhanced the interaction with Syntaxin 1. •PTPRT appears to regulate the fusion of synaptic vesicle through dephosphorylation. -- Abstract: PTPRT (protein tyrosine phosphatase receptor T), a brain-specific tyrosine phosphatase, has been found to regulate synaptic formation and development of hippocampal neurons, but its regulation mechanism is not yet fully understood. Here, Syntaxin-binding protein 1, a key component of synaptic vesicle fusion machinery, was identified asmore » a possible interaction partner and an endogenous substrate of PTPRT. PTPRT interacted with Syntaxin-binding protein 1 in rat synaptosome, and co-localized with Syntaxin-binding protein 1 in cultured hippocampal neurons. PTPRT dephosphorylated tyrosine 145 located around the linker between domain 1 and 2 of Syntaxin-binding protein 1. Syntaxin-binding protein 1 directly binds to Syntaxin 1, a t-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein, and plays a role as catalysts of SNARE complex formation. Syntaxin-binding protein 1 mutant mimicking non-phosphorylation (Y145F) enhanced the interaction with Syntaxin 1 compared to wild type, and therefore, dephosphorylation of Syntaxin-binding protein 1 appeared to be important for SNARE-complex formation. In conclusion, PTPRT could regulate the interaction of Syntaxin-binding protein 1 with Syntaxin 1, and as a result, the synaptic vesicle fusion appeared to be controlled through dephosphorylation of Syntaxin-binding protein 1.« less

Estimating black bear density using DNA data from hair snares

USGS Publications Warehouse

Gardner, B.; Royle, J. Andrew; Wegan, M.T.; Rainbolt, R.E.; Curtis, P.D.

2010-01-01

DNA-based mark-recapture has become a methodological cornerstone of research focused on bear species. The objective of such studies is often to estimate population size; however, doing so is frequently complicated by movement of individual bears. Movement affects the probability of detection and the assumption of closure of the population required in most models. To mitigate the bias caused by movement of individuals, population size and density estimates are often adjusted using ad hoc methods, including buffering the minimum polygon of the trapping array. We used a hierarchical, spatial capturerecapture model that contains explicit components for the spatial-point process that governs the distribution of individuals and their exposure to (via movement), and detection by, traps. We modeled detection probability as a function of each individual's distance to the trap and an indicator variable for previous capture to account for possible behavioral responses. We applied our model to a 2006 hair-snare study of a black bear (Ursus americanus) population in northern New York, USA. Based on the microsatellite marker analysis of collected hair samples, 47 individuals were identified. We estimated mean density at 0.20 bears/km2. A positive estimate of the indicator variable suggests that bears are attracted to baited sites; therefore, including a trap-dependence covariate is important when using bait to attract individuals. Bayesian analysis of the model was implemented in WinBUGS, and we provide the model specification. The model can be applied to any spatially organized trapping array (hair snares, camera traps, mist nests, etc.) to estimate density and can also account for heterogeneity and covariate information at the trap or individual level. ?? The Wildlife Society.

Wide-field piecemeal cold snare polypectomy of large sessile serrated polyps without a submucosal injection is safe.

PubMed

Tate, David J; Awadie, Halim; Bahin, Farzan F; Desomer, Lobke; Lee, Ralph; Heitman, Steven J; Goodrick, Kathleen; Bourke, Michael J

2018-03-01

BACKGROUND AND STUDY AIMS : Large series suggest endoscopic mucosal resection is safe and effective for the removal of large (≥ 10 mm) sessile serrated polyps (SSPs), but it exposes the patient to the risks of electrocautery, including delayed bleeding. We examined the feasibility and safety of piecemeal cold snare polypectomy (pCSP) for the resection of large SSPs.  Sequential large SSPs (10 - 35 mm) without endoscopic evidence of dysplasia referred over 12 months to a tertiary endoscopy center were considered for pCSP. A thin-wire snare was used in all cases. Submucosal injection was not performed. High definition imaging of the defect margin was used to ensure the absence of residual serrated tissue. Adverse events were assessed at 2 weeks and surveillance was planned for between 6 and 12 months.  41 SSPs were completely removed by pCSP in 34 patients. The median SSP size was 15 mm (interquartile range [IQR] 14.5 - 20 mm; range 10 - 35 mm). The median procedure duration was 4.5 minutes (IQR 1.4 - 6.3 minutes). There was no evidence of perforation or significant intraprocedural bleeding. At 2-week follow-up, there were no significant adverse events, including delayed bleeding and post polypectomy syndrome. First follow-up has been undertaken for 15 /41 lesions at a median of 6 months with no evidence of recurrence.  There is potential for pCSP to become the standard of care for non-dysplastic large SSPs. This could reduce the burden of removing SSPs on patients and healthcare systems, particularly by avoidance of delayed bleeding. © Georg Thieme Verlag KG Stuttgart · New York.

A SNARE-Like Superfamily Protein SbSLSP from the Halophyte Salicornia brachiata Confers Salt and Drought Tolerance by Maintaining Membrane Stability, K+/Na+ Ratio, and Antioxidant Machinery

PubMed Central

Singh, Dinkar; Yadav, Narendra Singh; Tiwari, Vivekanand; Agarwal, Pradeep K.; Jha, Bhavanath

2016-01-01

About 1000 salt-responsive ESTs were identified from an extreme halophyte Salicornia brachiata. Among these, a novel salt-inducible gene SbSLSP (Salicornia brachiata SNARE-like superfamily protein), showed up-regulation upon salinity and dehydration stress. The presence of cis-regulatory motifs related to abiotic stress in the putative promoter region supports our finding that SbSLSP gene is inducible by abiotic stress. The SbSLSP protein showed a high sequence identity to hypothetical/uncharacterized proteins from Beta vulgaris, Spinacia oleracea, Eucalyptus grandis, and Prunus persica and with SNARE-like superfamily proteins from Zostera marina and Arabidopsis thaliana. Bioinformatics analysis predicted a clathrin adaptor complex small-chain domain and N-myristoylation site in the SbSLSP protein. Subcellular localization studies indicated that the SbSLSP protein is mainly localized in the plasma membrane. Using transgenic tobacco lines, we establish that overexpression of SbSLSP resulted in elevated tolerance to salt and drought stress. The improved tolerance was confirmed by alterations in a range of physiological parameters, including high germination and survival rate, higher leaf chlorophyll contents, and reduced accumulation of Na+ ion and reactive oxygen species (ROS). Furthermore, overexpressing lines also showed lower water loss, higher cell membrane stability, and increased accumulation of proline and ROS-scavenging enzymes. Overexpression of SbSLSP also enhanced the transcript levels of ROS-scavenging and signaling enzyme genes. This study is the first investigation of the function of the SbSLSP gene as a novel determinant of salinity/drought tolerance. The results suggest that SbSLSP could be a potential candidate to increase salinity and drought tolerance in crop plants for sustainable agriculture in semi-arid saline soil. PMID:27313584

Expression and subcellular localization of the Qa-SNARE syntaxin17 in human eosinophils.

PubMed

Carmo, Lívia A S; Dias, Felipe F; Malta, Kássia K; Amaral, Kátia B; Shamri, Revital; Weller, Peter F; Melo, Rossana C N

2015-10-01

SNARE members mediate membrane fusion during intracellular trafficking underlying innate and adaptive immune responses by different cells. However, little is known about the expression and function of these proteins in human eosinophils, cells involved in allergic, inflammatory and immunoregulatory responses. Here, we investigate the expression and distribution of the Qa-SNARE syntaxin17 (STX17) within human eosinophils isolated from the peripheral blood. Flow cytometry and a pre-embedding immunonanogold electron microscopy (EM) technique that combines optimal epitope preservation and secondary Fab-fragments of antibodies linked to 1.4 nm gold particles for optimal access to microdomains, were used to investigate STX17. STX17 was detected within unstimulated eosinophils. Immunogold EM revealed STX17 on secretory granules and on granule-derived vesiculotubular transport carriers (Eosinophil Sombrero Vesicles-EoSVs). Quantitative EM analyses showed that 77.7% of the granules were positive for STX17 with a mean±SEM of 3.9±0.2 gold particles/granule. Labeling was present on both granule outer membranes and matrices while EoSVs showed clear membrane-associated labeling. STX17 was also present in secretory granules in eosinophils stimulated with the cytokine tumor necrosis factor alpha (TNF-α) or the CC-chemokine ligand 11 CCL11 (eotaxin-1), stimuli that induce eosinophil degranulation. The number of secretory granules labeled for STX17 was significantly higher in CCL11 compared with the unstimulated group. The level of cell labeling did not change when unstimulated cells were compared with TNF-α-stimulated eosinophils. The present study clearly shows by immunanonogold EM that STX17 is localized in eosinophil secretory granules and transport vesicles and might be involved in the transport of granule-derived cargos. Copyright © 2015 Elsevier Inc. All rights reserved.

SNARE-mediated Fusion of Single Proteoliposomes with Tethered Supported Bilayers in a Microfluidic Flow Cell Monitored by Polarized TIRF Microscopy

PubMed Central

Nikolaus, Joerg; Karatekin, Erdem

2016-01-01

In the ubiquitous process of membrane fusion the opening of a fusion pore establishes the first connection between two formerly separate compartments. During neurotransmitter or hormone release via exocytosis, the fusion pore can transiently open and close repeatedly, regulating cargo release kinetics. Pore dynamics also determine the mode of vesicle recycling; irreversible resealing results in transient, "kiss-and-run" fusion, whereas dilation leads to full fusion. To better understand what factors govern pore dynamics, we developed an assay to monitor membrane fusion using polarized total internal reflection fluorescence (TIRF) microscopy with single molecule sensitivity and ~15 msec time resolution in a biochemically well-defined in vitro system. Fusion of fluorescently labeled small unilamellar vesicles containing v-SNARE proteins (v-SUVs) with a planar bilayer bearing t-SNAREs, supported on a soft polymer cushion (t-SBL, t-supported bilayer), is monitored. The assay uses microfluidic flow channels that ensure minimal sample consumption while supplying a constant density of SUVs. Exploiting the rapid signal enhancement upon transfer of lipid labels from the SUV to the SBL during fusion, kinetics of lipid dye transfer is monitored. The sensitivity of TIRF microscopy allows tracking single fluorescent lipid labels, from which lipid diffusivity and SUV size can be deduced for every fusion event. Lipid dye release times can be much longer than expected for unimpeded passage through permanently open pores. Using a model that assumes retardation of lipid release is due to pore flickering, a pore "openness", the fraction of time the pore remains open during fusion, can be estimated. A soluble marker can be encapsulated in the SUVs for simultaneous monitoring of lipid and soluble cargo release. Such measurements indicate some pores may reseal after losing a fraction of the soluble cargo. PMID:27585113

Interaction of Munc18c and syntaxin4 facilitates invadopodium formation and extracellular matrix invasion of tumor cells.

PubMed

Brasher, Megan I; Martynowicz, David M; Grafinger, Olivia R; Hucik, Andrea; Shanks-Skinner, Emma; Uniacke, James; Coppolino, Marc G

2017-09-29

Tumor cell invasion involves targeted localization of proteins required for interactions with the extracellular matrix and for proteolysis. The localization of many proteins during these cell-extracellular matrix interactions relies on membrane trafficking mediated in part by SNAREs. The SNARE protein syntaxin4 (Stx4) is involved in the formation of invasive structures called invadopodia; however, it is unclear how Stx4 function is regulated during tumor cell invasion. Munc18c is known to regulate Stx4 activity, and here we show that Munc18c is required for Stx4-mediated invadopodium formation and cell invasion. Biochemical and microscopic analyses revealed a physical association between Munc18c and Stx4, which was enhanced during invadopodium formation, and that a reduction in Munc18c expression decreases invadopodium formation. We also found that an N-terminal Stx4-derived peptide associates with Munc18c and inhibits endogenous interactions of Stx4 with synaptosome-associated protein 23 (SNAP23) and vesicle-associated membrane protein 2 (VAMP2). Furthermore, expression of the Stx4 N-terminal peptide decreased invadopodium formation and cell invasion in vitro Of note, cells expressing the Stx4 N-terminal peptide exhibited impaired trafficking of membrane type 1 matrix metalloproteinase (MT1-MMP) and EGF receptor (EGFR) to the cell surface during invadopodium formation. Our findings implicate Munc18c as a regulator of Stx4-mediated trafficking of MT1-MMP and EGFR, advancing our understanding of the role of SNARE function in the localization of proteins that drive tumor cell invasion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Munc13-4 functions as a Ca2+ sensor for homotypic secretory granule fusion to generate endosomal exocytic vacuoles.

PubMed

Woo, Sang Su; James, Declan J; Martin, Thomas F J

2017-03-15

Munc13-4 is a Ca 2+ -dependent SNARE (soluble N -ethylmaleimide-sensitive factor attachment protein receptor)- and phospholipid-binding protein that localizes to and primes secretory granules (SGs) for Ca 2+ -evoked secretion in various secretory cells. Studies in mast cell-like RBL-2H3 cells provide direct evidence that Munc13-4 with its two Ca 2+ -binding C2 domains functions as a Ca 2+ sensor for SG exocytosis. Unexpectedly, Ca 2+ stimulation also generated large (>2.4 μm in diameter) Munc13-4 + /Rab7 + /Rab11 + endosomal vacuoles. Vacuole generation involved the homotypic fusion of Munc13-4 + /Rab7 + SGs, followed by a merge with Rab11 + endosomes, and depended on Ca 2+ binding to Munc13-4. Munc13-4 promoted the Ca 2+ -stimulated fusion of VAMP8-containing liposomes with liposomes containing exocytic or endosomal Q-SNAREs and directly interacted with late endosomal SNARE complexes. Thus Munc13-4 is a tethering/priming factor and Ca 2+ sensor for both heterotypic SG-plasma membrane and homotypic SG-SG fusion. Total internal reflection fluorescence microscopy imaging revealed that vacuoles were exocytic and mediated secretion of β-hexosaminidase and cytokines accompanied by Munc13-4 diffusion onto the plasma membrane. The results provide new molecular insights into the mechanism of multigranular compound exocytosis commonly observed in various secretory cells. © 2017 Woo et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Elena Guardincerri: Tracking muons to reduce nuclear threats and help preserve architectural treasures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Mauro, Diana; Guardincerri, Elena

When Elena Guardincerri was a physics PhD student at the University of Genova, she considered muons a nuisance. She built muon detectors to snare these secondary cosmic rays, which were interfering with her experiments to study elusive neutrinos.

The quantum physics of synaptic communication via the SNARE protein complex.

PubMed

Georgiev, Danko D; Glazebrook, James F

2018-07-01

Twenty five years ago, Sir John Carew Eccles together with Friedrich Beck proposed a quantum mechanical model of neurotransmitter release at synapses in the human cerebral cortex. The model endorsed causal influence of human consciousness upon the functioning of synapses in the brain through quantum tunneling of unidentified quasiparticles that trigger the exocytosis of synaptic vesicles, thereby initiating the transmission of information from the presynaptic towards the postsynaptic neuron. Here, we provide a molecular upgrade of the Beck and Eccles model by identifying the quantum quasiparticles as Davydov solitons that twist the protein α-helices and trigger exocytosis of synaptic vesicles through helical zipping of the SNARE protein complex. We also calculate the observable probabilities for exocytosis based on the mass of this quasiparticle, along with the characteristics of the potential energy barrier through which tunneling is necessary. We further review the current experimental evidence in support of this novel bio-molecular model as presented. Copyright © 2018 Elsevier Ltd. All rights reserved.

EARP, a multisubunit tethering complex involved in endocytic recycling

PubMed Central

Schindler, Christina; Chen, Yu; Pu, Jing; Guo, Xiaoli; Bonifacino, Juan S.

2015-01-01

Recycling of endocytic receptors to the cell surface involves passage through a series of membrane-bound compartments by mechanisms that are poorly understood. In particular, it is unknown if endocytic recycling requires the function of multisubunit tethering complexes, as is the case for other intracellular trafficking pathways. Herein we describe a tethering complex named Endosome-Associated Recycling Protein (EARP) that is structurally related to the previously described Golgi-Associated Retrograde Protein (GARP) complex. Both complexes share the Ang2, Vps52 and Vps53 subunits, but EARP comprises an uncharacterized protein, Syndetin, in place of the Vps54 subunit of GARP. This change determines differential localization of EARP to recycling endosomes and GARP to the Golgi complex. EARP interacts with the target-SNARE Syntaxin 6 and various cognate SNAREs. Depletion of Syndetin or Syntaxin 6 delays recycling of internalized transferrin to the cell surface. These findings implicate EARP in canonical membrane-fusion events in the process of endocytic recycling. PMID:25799061

A Model for Membrane Fusion

NASA Astrophysics Data System (ADS)

Ngatchou, Annita

2010-01-01

Pheochromocytoma is a tumor of the adrenal gland which originates from chromaffin cells and is characterized by the secretion of excessive amounts of neurotransmitter which lead to high blood pressure and palpitations. Pheochromocytoma contain membrane bound granules that store neurotransmitter. The release of these stored molecules into the extracellular space occurs by fusion of the granule membrane with the cell plasma membrane, a process called exocytosis. The molecular mechanism of this membrane fusion is not well understood. It is proposed that the so called SNARE proteins [1] are the pillar of vesicle fusion as their cleavage by clostridial toxin notably, Botulinum neurotoxin and Tetanus toxin abrogate the secretion of neurotransmitter [2]. Here, I describe how physical principles are applied to a biological cell to explore the role of the vesicle SNARE protein synaptobrevin-2 in easing granule fusion. The data presented here suggest a paradigm according to which the movement of the C-terminal of synaptobrevin-2 disrupts the lipid bilayer to form a fusion pore through which molecules can exit.

Neuron Specific Rab4 Effector GRASP-1 Coordinates Membrane Specialization and Maturation of Recycling Endosomes

PubMed Central

Hoogenraad, Casper C.; Popa, Ioana; Futai, Kensuke; Sanchez-Martinez, Emma; Wulf, Phebe S.; van Vlijmen, Thijs; Dortland, Bjorn R.; Oorschot, Viola; Govers, Roland; Monti, Maria; Heck, Albert J. R.; Sheng, Morgan; Klumperman, Judith; Rehmann, Holger; Jaarsma, Dick; Kapitein, Lukas C.; van der Sluijs, Peter

2010-01-01

The endosomal pathway in neuronal dendrites is essential for membrane receptor trafficking and proper synaptic function and plasticity. However, the molecular mechanisms that organize specific endocytic trafficking routes are poorly understood. Here, we identify GRIP-associated protein-1 (GRASP-1) as a neuron-specific effector of Rab4 and key component of the molecular machinery that coordinates recycling endosome maturation in dendrites. We show that GRASP-1 is necessary for AMPA receptor recycling, maintenance of spine morphology, and synaptic plasticity. At the molecular level, GRASP-1 segregates Rab4 from EEA1/Neep21/Rab5-positive early endosomal membranes and coordinates the coupling to Rab11-labelled recycling endosomes by interacting with the endosomal SNARE syntaxin 13. We propose that GRASP-1 connects early and late recycling endosomal compartments by forming a molecular bridge between Rab-specific membrane domains and the endosomal SNARE machinery. The data uncover a new mechanism to achieve specificity and directionality in neuronal membrane receptor trafficking. PMID:20098723

Alarm!!! A UFO inside the heart.

PubMed

Santoro, Giuseppe; Castaldi, Biagio; Iacono, Carola; Giugno, Luca; Gaio, Gianpiero; Russo, Maria G

2012-10-01

An 8-year-old asymptomatic child was referred for surgical repair of coronary sinus atrial septal defect resulting in significant left-to-right shunt and right chamber volume overload. The septal fenestration was located near to its drainage site into the right atrium. Due to this seemingly favourable anatomy, transcatheter closure of the septal defect was performed using an Amplatzer Septal Occluder device. The echocardiographic postprocedural evaluation imaged the occluding device almost perpendicular to the atrial septum, seemingly floating above the mitral valve orifice, like an alien spaceship inside the heart.

Good News for Beginning Drummers

ERIC Educational Resources Information Center

Brown, Paul K.

2005-01-01

In the minds of some music teachers, school bands and orchestras are divided into two camps: the talented and the musically challenged. Considering their conventional methods of introducing rudiments to their young percussionists, it's no wonder that some students struggle. Take the snare drum as a classic example. First, the percussionist must…

The efficacy of wire and glue hair snares in identifying mesocarnivores

Treesearch

William J. Zielinski; Fredrick V. Schlexer; Kristine L. Pilgrim; Michael K. Schwartz

2006-01-01

Track plates and cameras are proven methods for detecting and identifying fishers (Martes pennant) and other mesocarnivores. But these methods are inadequate to achieve demographic and population-monitoring objectives that require identifying sex and individuals. Although noninvasive collection of biological material for genetic analysis (i.e.,...

Teaching Techniques for Accessory Percussion

ERIC Educational Resources Information Center

Micallef, Ken

2007-01-01

Everyone is familiar with the main percussion instruments of the contemporary orchestra: bass drum, snare drum, suspended cymbal, vibraphone, and timpani. But as source material broadens, so do the demands placed on the percussion section. Accessory, or auxiliary percussion, can make the difference between a typical rendition of a well-known piece…

Increased lipolysis and altered lipid homeostasis protect y-synuclein null mutant mice from diet-induced obesity

USDA-ARS?s Scientific Manuscript database

Synucleins are a family of homologous proteins principally known for their involvement in neurodegeneration. In neurons a-synuclein promotes assembly of SNARE complexes required for fusion of synaptic vesicles with the plasma membrane during neurotransmitter release. Y-synuclein is highly expressed ...

The Snare Drum in Three Dimensions

ERIC Educational Resources Information Center

Sanderl, Robert

2011-01-01

Any seasoned band teacher can attest to the challenge of teaching percussion. Many young percussionists face a sense of alienation from the rest of the ensemble because of a perception that percussionists have a lesser understanding of music than other instrumentalists. This perception has improved because many schools now include bell kits in…

Immediate and mid-term clinical course after percutaneous closure of paravalvular leakage.

PubMed

Sánchez-Recalde, Angel; Moreno, Raúl; Galeote, Guillermo; Jimenez-Valero, Santiago; Calvo, Luis; Sevillano, Joel Hernández; Arroyo-Ucar, Eduardo; López, Teresa; Mesa, José M; López-Sendón, José L

2014-08-01

Percutaneous closure of paravalvular leakage is an alternative to surgery in high-risk patients, but its use has been limited by a lack of specific devices. More appropriate devices-like the Amplatzer Vascular Plug III-have recently been developed, but information about their efficacy and safety is still scarce. The objective of the present study was to assess the mid-term results of paravalvular leakage closure with this device. We analyzed the clinical and echocardiographic course both in-hospital and mid-term (13 [9] months) in a series of 20 consecutive patients (age, 68 years; logistic EuroSCORE, 29) with paravalvular leakage and attempted percutaneous closure. Closure was attempted for 23 leaks (17 mitral and 6 aortic) during 22 procedures in 20 patients. Implantation was successful in 87% of the leaks and the procedure was successful in 83%-with success being defined as a reduction in regurgitation of ≥ 1 degree. Survival at 1 year was 64.7% and survival free of the composite event of death/surgery was 58.8%. The degree of residual regurgitation was not associated with mortality but was associated with functional status. Survivors showed significant improvement in functional class. Percutaneous closure of leakage with the Amplatzer Vascular Plug III is safe and efficient in the mid-term. However, mortality among high-risk patients is high independently of the degree of residual regurgitation, indicating that these procedures are performed when heart disease has reached an advanced stage. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

The Amplatz canine duct occluder: a novel device for patent ductus arteriosus occlusion.

PubMed

Nguyenba, Thaibinh P; Tobias, Anthony H

2007-11-01

The Amplatz canine duct occluder (ACDO) is a nitinol mesh device with a short waist that separates a flat distal disc from a cupped proximal disc. The device is designed to conform to the morphology of the canine patent ductus arteriosus (PDA). PDA dimensions are determined by angiography, and a guiding catheter is advanced into the main pulmonary artery via the aorta and PDA. An ACDO with a waist diameter approximately twice the angiographic minimal ductal diameter (MDD) is advanced via the catheter using an attached delivery cable until the flat distal disc deploys within the main pulmonary artery. The partially deployed ACDO, guiding catheter, and delivery cable are retracted until the distal disc engages the pulmonic ostium of the PDA. With the delivery cable stabilized, the catheter is retracted to deploy the waist across the pulmonic ostium and cupped proximal disc within the ductal ampulla. Tension on the delivery cable is released, and correct ACDO positioning and stability are confirmed by observing that the device assumes its native shape, back-and-forth maneuvering of the delivery cable, and a small contrast injection made through the guiding catheter. The delivery cable is detached and removed with the guiding catheter. To assess for any residual ductal flow, an angiogram is performed at the conclusion of the procedure, followed by Doppler echocardiography at 1 day and 3 months post-procedure. PDA occlusion in dogs with the ACDO is straightforward and extremely effective across a wide range of body weights, somatotypes, MDDs, and ductal morphologies.

Incomplete aneurysm coverage after patent foramen ovale closure in patients with huge atrial septal aneurysm: effects on left atrial functional remodeling.

PubMed

Rigatelli, Gianluca; Ronco, Federico; Cardaioli, Paolo; Dell'avvocata, Fabio; Braggion, Gabriele; Giordan, Massimo; Aggio, Silvio

2010-08-01

Large devices are often implanted to treat patent foramen ovale (PFO) and atrial septal aneurysm (ASA) with increase risk of erosion and thrombosis. Our study is aimed to assess the impact on left atrium functional remodeling and clinical outcomes of partial coverage of the approach using moderately small Amplatzer ASD Cribriform Occluder in patients with large PFO and ASA. We prospectively enrolled 30 consecutive patients with previous stroke (mean age 36 +/- 9.5 years, 19 females), significant PFO, and large ASA referred to our center for catheter-based PFO closure. Left atrium (LA) passive and active emptying, LA conduit function, and LA ejection fraction were computed before and after 6 months from the procedure by echocardiography. The preclosure values were compared to values of a normal healthy population of sex and heart rate matched 30 patients. Preclosure values demonstrated significantly greater reservoir function as well as passive and active emptying, with significantly reduced conduit function and LA ejection fraction, when compared normal healthy subjects. All patients underwent successful transcatheter closure (25 mm device in 15 patients, 30 mm device in 6 patients, mean ratio device/diameter of the interatrial septum = 0.74). Incomplete ASA coverage in both orthogonal views was observed in 21 patients. Compared to patients with complete coverage, there were no differences in LA functional parameters and occlusion rates. This study confirmed that large ASAs are associated with LA dysfunction. The use of relatively small Amplatzer ASD Cribriform Occluder devices is probably effective enough to promote functional remodeling of the left atrium.

Relationship between Device Size and Body Weight in Dogs with Patent Ductus Arteriosus Undergoing Amplatz Canine Duct Occluder Deployment.

PubMed

Wesselowski, S; Saunders, A B; Gordon, S G

2017-09-01

Deployment of the Amplatz Canine Duct Occluder (ACDO) is the preferred method for minimally invasive occlusion of patent ductus arteriosus (PDA) in dogs, with appropriate device sizing crucial to successful closure. Dogs of any body weight can be affected by PDA. To describe the range of ACDO sizes deployed in dogs of various body weights for improved procedural planning and inventory selection and to investigate for correlation between minimal ductal diameter (MDD) and body weight. A total of 152 dogs undergoing ACDO deployment between 2008 and 2016. Body weight, age, breed, sex, and MDD obtained by angiography (MDD-A), MDD obtained by transesophageal echocardiography (MDD-TEE), and ACDO size deployed were retrospectively evaluated. Correlation between body weight and ACDO size, MDD-A and MDD-TEE was poor, with R-squared values of 0.4, 0.36, and 0.3, respectively. Femoral artery diameter in the smallest population of dogs placed inherent limitations on the use of larger device sizes, with no limitations on the wide range of device sizes required as patient size increased. The most commonly used ACDO devices were size 3 through 6, representing 57% of the devices deployed within the entire study population. Patent ductus arteriosus anatomy varies on an individual basis, with poor correlation between MDD and body weight. Weight-based assumptions about expected ACDO device size for a given patient are not recommended. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Genetic Diversity and Human Equality.

ERIC Educational Resources Information Center

Dobzhansky, Theodosius

The idea of equality often, if not frequently, bogs down in confusion and apparent contradictions; equality is confused with identity, and diversity with inequality. It would seem that the easiest way to discredit the idea of equality is to show that people are innately, genetically, and, therefore, irremediably diverse and unlike. The snare is,…

Pickin’ Up Good Vibrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jeremy C.

Although conformational change has long been recognized as critical to protein function, whether the same goes for equilibrium dynamical fluctuations has been the subject of myriad squabbles. There are also those who rigidly deny any dynamical effects, those who claim fluctuations drive functional conformational change, while those who claim to have snared exquisitely evolved function-channeling vibrations.

Pickin’ Up Good Vibrations

DOE PAGES

Smith, Jeremy C.

2017-03-14

Although conformational change has long been recognized as critical to protein function, whether the same goes for equilibrium dynamical fluctuations has been the subject of myriad squabbles. There are also those who rigidly deny any dynamical effects, those who claim fluctuations drive functional conformational change, while those who claim to have snared exquisitely evolved function-channeling vibrations.

SNARE-encoding genes VdSec22 and VdSso1 mediate protein secretion required for full virulence in Verticillium dahliae

USDA-ARS?s Scientific Manuscript database

Proteins that mediate cellular and subcellular membrane fusion are key factors in vesicular trafficking in all eukaryotic cells, including the secretion and transport of plant pathogen virulence factors. In this study, we identified vesicle fusion components that included 22 soluble N-ethylmaleimide...

Noninvasive and cost-effective trapping method for monitoring sensitive mammal populations

Treesearch

Stephanie E. Trapp; Elizabeth A. Flaherty

2017-01-01

Noninvasive sampling methods provide a means to monitor endangered, threatened, or sensitive species or populations while increasing the efficacy of personnel effort and time. We developed a monitoring protocol that utilizes single-capture hair snares and analysis of morphological features of hair for evaluating populations. During 2015, we used the West Virginia...

A SNARE-like protein and biotin are implicated in soybean cyst nematode virulence

USDA-ARS?s Scientific Manuscript database

Some phytoparasitic nematodes have the ability to infect and reproduce on plants that are normally considered resistant to nematode infection. Such nematodes are referred to as virulent and the mechanisms they use to evade or suppress host plant defenses are not well understood. Here, we report the ...

Respiratory-aspirated 35-mm hairpin successfully retrieved with a Teflon® snare system under fluoroscopic guidance via a split endotracheal tube: a useful technique in cases of failed extraction by bronchoscopy and avoiding the need for a thoracotomy.

PubMed

Gill, S S; Pease, R A; Ashwin, C J; Gill, S S; Tait, N P

2012-09-01

Respiratory foreign body aspiration (FBA) is a common global health problem requiring prompt recognition and early treatment to prevent potentially fatal complications. The majority of FBAs are due to organic objects and treatment is usually via either endoscopic or surgical extraction. FBA of a straight hairpin has been described as a unique entity in the literature, occurring most commonly in females, particularly during adolescence. In the process of inserting hairpins, the pins will typically be between the teeth with the head tilted backwards, while tying their hair with both hands. This position increases the risk of aspiration, particularly if there is any sudden coughing or laughing. To our knowledge, this is the first case report of a 35-mm straight metallic hairpin foreign body that has been successfully retrieved by a radiological snare system under fluoroscopic guidance. This was achieved with the use of a split endotracheal tube, and therefore avoided the need for a thoracotomy in an adolescent female patient.

Botulinum neurotoxin: a marvel of protein design.

PubMed

Montal, Mauricio

2010-01-01

Botulinum neurotoxin (BoNT), the causative agent of botulism, is acknowledged to be the most poisonous protein known. BoNT proteases disable synaptic vesicle exocytosis by cleaving their cytosolic SNARE (soluble NSF attachment protein receptor) substrates. BoNT is a modular nanomachine: an N-terminal Zn(2+)-metalloprotease, which cleaves the SNAREs; a central helical protein-conducting channel, which chaperones the protease across endosomes; and a C-terminal receptor-binding module, consisting of two subdomains that determine target specificity by binding to a ganglioside and a protein receptor on the cell surface and triggering endocytosis. For BoNT, functional complexity emerges from its modular design and the tight interplay between its component modules--a partnership with consequences that surpass the simple sum of the individual component's action. BoNTs exploit this design at each step of the intoxication process, thereby achieving an exquisite toxicity. This review summarizes current knowledge on the structure of individual modules and presents mechanistic insights into how this protein machine evolved to this level of sophistication. Understanding the design principles underpinning the function of such a dynamic modular protein remains a challenging task.

SLY1 and Syntaxin 18 specify a distinct pathway for procollagen VII export from the endoplasmic reticulum

PubMed Central

Nogueira, Cristina; Erlmann, Patrik; Villeneuve, Julien; Santos, António JM; Martínez-Alonso, Emma; Martínez-Menárguez, José Ángel; Malhotra, Vivek

2014-01-01

TANGO1 binds and exports Procollagen VII from the endoplasmic reticulum (ER). In this study, we report a connection between the cytoplasmic domain of TANGO1 and SLY1, a protein that is required for membrane fusion. Knockdown of SLY1 by siRNA arrested Procollagen VII in the ER without affecting the recruitment of COPII components, general protein secretion, and retrograde transport of the KDEL-containing protein BIP, and ERGIC53. SLY1 is known to interact with the ER-specific SNARE proteins Syntaxin 17 and 18, however only Syntaxin 18 was required for Procollagen VII export. Neither SLY1 nor Syntaxin 18 was required for the export of the equally bulky Procollagen I from the ER. Altogether, these findings reveal the sorting of bulky collagen family members by TANGO1 at the ER and highlight the existence of different export pathways for secretory cargoes one of which is mediated by the specific SNARE complex containing SLY1 and Syntaxin 18. DOI: http://dx.doi.org/10.7554/eLife.02784.001 PMID:24842878

The SNARE Protein Syntaxin 3 Confers Specificity for Polarized Axonal Trafficking in Neurons

PubMed Central

Soo Hoo, Linda; Banna, Chris D.; Radeke, Carolyn M.; Sharma, Nikunj; Albertolle, Mary E.; Low, Seng Hui; Weimbs, Thomas; Vandenberg, Carol A.

2016-01-01

Cell polarity and precise subcellular protein localization are pivotal to neuronal function. The SNARE machinery underlies intracellular membrane fusion events, but its role in neuronal polarity and selective protein targeting remain unclear. Here we report that syntaxin 3 is involved in orchestrating polarized trafficking in cultured rat hippocampal neurons. We show that syntaxin 3 localizes to the axonal plasma membrane, particularly to axonal tips, whereas syntaxin 4 localizes to the somatodendritic plasma membrane. Disruption of a conserved N-terminal targeting motif, which causes mislocalization of syntaxin 3, results in coincident mistargeting of the axonal cargos neuron-glia cell adhesion molecule (NgCAM) and neurexin, but not transferrin receptor, a somatodendritic cargo. Similarly, RNAi-mediated knockdown of endogenous syntaxin 3 leads to partial mistargeting of NgCAM, demonstrating that syntaxin 3 plays an important role in its targeting. Additionally, overexpression of syntaxin 3 results in increased axonal growth. Our findings suggest an important role for syntaxin 3 in maintaining neuronal polarity and in the critical task of selective trafficking of membrane protein to axons. PMID:27662481

The SNARE Protein Syntaxin 3 Confers Specificity for Polarized Axonal Trafficking in Neurons.

PubMed

Soo Hoo, Linda; Banna, Chris D; Radeke, Carolyn M; Sharma, Nikunj; Albertolle, Mary E; Low, Seng Hui; Weimbs, Thomas; Vandenberg, Carol A

Cell polarity and precise subcellular protein localization are pivotal to neuronal function. The SNARE machinery underlies intracellular membrane fusion events, but its role in neuronal polarity and selective protein targeting remain unclear. Here we report that syntaxin 3 is involved in orchestrating polarized trafficking in cultured rat hippocampal neurons. We show that syntaxin 3 localizes to the axonal plasma membrane, particularly to axonal tips, whereas syntaxin 4 localizes to the somatodendritic plasma membrane. Disruption of a conserved N-terminal targeting motif, which causes mislocalization of syntaxin 3, results in coincident mistargeting of the axonal cargos neuron-glia cell adhesion molecule (NgCAM) and neurexin, but not transferrin receptor, a somatodendritic cargo. Similarly, RNAi-mediated knockdown of endogenous syntaxin 3 leads to partial mistargeting of NgCAM, demonstrating that syntaxin 3 plays an important role in its targeting. Additionally, overexpression of syntaxin 3 results in increased axonal growth. Our findings suggest an important role for syntaxin 3 in maintaining neuronal polarity and in the critical task of selective trafficking of membrane protein to axons.

BLOC-1 and BLOC-3 regulate VAMP7 cycling to and from melanosomes via distinct tubular transport carriers

PubMed Central

Delevoye, Cédric; Romao, Maryse; Owen, David J.; Raposo, Graça

2016-01-01

Endomembrane organelle maturation requires cargo delivery via fusion with membrane transport intermediates and recycling of fusion factors to their sites of origin. Melanosomes and other lysosome-related organelles obtain cargoes from early endosomes, but the fusion machinery involved and its recycling pathway are unknown. Here, we show that the v-SNARE VAMP7 mediates fusion of melanosomes with tubular transport carriers that also carry the cargo protein TYRP1 and that require BLOC-1 for their formation. Using live-cell imaging, we identify a pathway for VAMP7 recycling from melanosomes that employs distinct tubular carriers. The recycling carriers also harbor the VAMP7-binding scaffold protein VARP and the tissue-restricted Rab GTPase RAB38. Recycling carrier formation is dependent on the RAB38 exchange factor BLOC-3. Our data suggest that VAMP7 mediates fusion of BLOC-1–dependent transport carriers with melanosomes, illuminate SNARE recycling from melanosomes as a critical BLOC-3–dependent step, and likely explain the distinct hypopigmentation phenotypes associated with BLOC-1 and BLOC-3 deficiency in Hermansky–Pudlak syndrome variants. PMID:27482051

Morphine Antidependence of Erythroxylum cuneatum (Miq.) Kurz in Neurotransmission Processes In Vitro

PubMed Central

Adenan, Mohd Ilham; Amom, Zulkhairi

2016-01-01

Opiate abuse has been studied to cause adaptive changes observed in the presynaptic release and the mediated-synaptic plasticity proteins. The involvement of neuronal SNARE proteins reveals the role of the neurotransmitter release in expressing the opioid actions. The present study was designed to determine the effect of the alkaloid extract of Erythroxylum cuneatum (E. cuneatum) against chronic morphine and the influences of E. cuneatum on neurotransmission processes observed in vitro. The human neuroblastoma cell line, SK-N-SH, was treated with the morphine, methadone, or E. cuneatum. The cell lysates were collected and tested for α-synuclein, calmodulin, vesicle-associated membrane protein 2 (VAMP 2), and synaptotagmin 1. The extract of E. cuneatum was observed to upregulate the decreased expression of dependence proteins, namely, α-synuclein and calmodulin. The effects were comparable to methadone and control. The expressions of VAMP 2 and synaptotagmin 1 were normalised by the plant and methadone. The extract of E. cuneatum was postulated to treat dependence symptoms after chronic morphine and improve the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) protein involved in synaptic vesicle after. PMID:27974903

Gastric Bezoar Treatment by Endoscopic Fragmentation in Combination with Pepsi-Cola® Administration

PubMed Central

Iwamuro, Masaya; Yunoki, Naoko; Tomoda, Jun; Nakamura, Kazuhiro; Okada, Hiroyuki; Yamamoto, Kazuhide

2015-01-01

Patient: Male, 86 Final Diagnosis: Gastric bezoar Symptoms: — Medication: Cola Clinical Procedure: Endoscopic fragmentation after gastric lavage with Pepsi-Cola Specialty: Gastroenterology and Hepatology Objective: Unusual setting of medical care Background: Although bezoar dissolution by Coca-Cola® has been described in case reports and case series, to the best of our knowledge, the usefulness of other cola products such as Pepsi-Cola® has never been reported in the English literature. Case Report: An 86-year-old Taiwanese man was diagnosed with a gastric bezoar. Endoscopic fragmentation with a polypectomy snare was attempted twice but failed to remove the bezoar. Subsequently, 500 mL of Pepsi NEX Zero® was administered daily for 4 days via nasogastric tube. The bezoar was softened and successfully fragmented by the polypectomy snare and needle-knife devices on the third attempt. Conclusions: This report presents the first case of a gastric bezoar successfully treated by endoscopic fragmentation in combination with Pepsi-Cola® administration, suggesting the possible utility of cola beverages in bezoar treatment, regardless of product brands. PMID:26164451

Altered mechanisms underlying the abnormal glutamate release in amyotrophic lateral sclerosis at a pre-symptomatic stage of the disease.

PubMed

Bonifacino, Tiziana; Musazzi, Laura; Milanese, Marco; Seguini, Mara; Marte, Antonella; Gallia, Elena; Cattaneo, Luca; Onofri, Franco; Popoli, Maurizio; Bonanno, Giambattista

2016-11-01

Abnormal Glu release occurs in the spinal cord of SOD1(G93A) mice, a transgenic animal model for human ALS. Here we studied the mechanisms underlying Glu release in spinal cord nerve terminals of SOD1(G93A) mice at a pre-symptomatic disease stage (30days) and found that the basal release of Glu was more elevated in SOD1(G93A) with respect to SOD1 mice, and that the surplus of release relies on synaptic vesicle exocytosis. Exposure to high KCl or ionomycin provoked Ca(2+)-dependent Glu release that was likewise augmented in SOD1(G93A) mice. Equally, the Ca(2+)-independent hypertonic sucrose-induced Glu release was abnormally elevated in SOD1(G93A) mice. Also in this case, the surplus of Glu release was exocytotic in nature. We could determine elevated cytosolic Ca(2+) levels, increased phosphorylation of Synapsin-I, which was causally related to the abnormal Glu release measured in spinal cord synaptosomes of pre-symptomatic SOD1(G93A) mice, and increased phosphorylation of glycogen synthase kinase-3 at the inhibitory sites, an event that favours SNARE protein assembly. Western blot experiments revealed an increased number of SNARE protein complexes at the nerve terminal membrane, with no changes of the three SNARE proteins and increased expression of synaptotagmin-1 and β-Actin, but not of an array of other release-related presynaptic proteins. These results indicate that the abnormal exocytotic Glu release in spinal cord of pre-symptomatic SOD1(G93A) mice is mainly based on the increased size of the readily releasable pool of vesicles and release facilitation, supported by plastic changes of specific presynaptic mechanisms. Copyright © 2016 Elsevier Inc. All rights reserved.

Techniques for trans-catheter retrieval of embolized Nit-Occlud® PDA-R and ASD-R devices.

PubMed

Sinha, Sanjay; Levi, Daniel; Peirone, Alejandro; Pedra, Carlos

2018-02-15

Nit-Occlud ® (atrial septal defect) ASD-R and (patent ductus arteriosus) PDA-R devices are used outside the United States for percutaneous closure of the patent ductus arteriosus and atrial septal defects. When embolization occurs, these devices have been difficult to retrieve. Bench simulations of retrieval of PDA-R and ASD-R devices were performed in a vascular model. Retrieval of each device was attempted using snare techniques or with bioptome forceps with a range of devices. The same devices were then intentionally embolized in an animal model. Retrieval methods were systematically tested in a range of sheath sizes, and graded in terms of difficulty and retrieval time. Devices that were grasped by the bioptome in the center of the proximal part of the devices were easily retrieved in both models. Bench studies determined the minimum sheath sizes needed for retrieval of each device with this method. In general sheathes two french sizes greater than the delivery sheath were successful with this technique. Three out of the four PDA-R devices were successfully retrieved in vivo. Two were retrieved by grasping the middle of the PA end of the PDA-R device with a Maslanka bioptome and one small PDA-R device was retrieved using a 10 mm Snare. Four of the five ASD-R devices were retrieved successfully grasping the right atrial ASD-R disc or by passing a wire through the device and snaring this loop. For ASD-R 28 and 30 mm devices, a double bioptome technique was needed to retrieve the device. ASD-R and PDA-R devices can be successfully retrieved in the catheterization lab. It is critical to grab the center portion of the right atrial disc of the ASD-R device or pulmonary portion of the PDA-R device and to use adequately sized sheathes. © 2018 Wiley Periodicals, Inc.

Robust syntaxin-4 immunoreactivity in mammalian horizontal cell processes

PubMed Central

HIRANO, ARLENE A.; BRANDSTÄTTER, JOHANN HELMUT; VILA, ALEJANDRO; BRECHA, NICHOLAS C.

2009-01-01

Horizontal cells mediate inhibitory feed-forward and feedback communication in the outer retina; however, mechanisms that underlie transmitter release from mammalian horizontal cells are poorly understood. Toward determining whether the molecular machinery for exocytosis is present in horizontal cells, we investigated the localization of syntaxin-4, a SNARE protein involved in targeting vesicles to the plasma membrane, in mouse, rat, and rabbit retinae using immunocytochemistry. We report robust expression of syntaxin-4 in the outer plexiform layer of all three species. Syntaxin-4 occurred in processes and tips of horizontal cells, with regularly spaced, thicker sandwich-like structures along the processes. Double labeling with syntaxin-4 and calbindin antibodies, a horizontal cell marker, demonstrated syntaxin-4 localization to horizontal cell processes; whereas, double labeling with PKC antibodies, a rod bipolar cell (RBC) marker, showed a lack of co-localization, with syntaxin-4 immunolabeling occurring just distal to RBC dendritic tips. Syntaxin-4 immunolabeling occurred within VGLUT-1-immunoreactive photoreceptor terminals and underneath synaptic ribbons, labeled by CtBP2/RIBEYE antibodies, consistent with localization in invaginating horizontal cell tips at photoreceptor triad synapses. Vertical sections of retina immunostained for syntaxin-4 and peanut agglutinin (PNA) established that the prominent patches of syntaxin-4 immunoreactivity were adjacent to the base of cone pedicles. Horizontal sections through the OPL indicate a one-to-one co-localization of syntaxin-4 densities at likely all cone pedicles, with syntaxin-4 immunoreactivity interdigitating with PNA labeling. Pre-embedding immuno-electron microscopy confirmed the subcellular localization of syntaxin-4 labeling to lateral elements at both rod and cone triad synapses. Finally, co-localization with SNAP-25, a possible binding partner of syntaxin-4, indicated co-expression of these SNARE proteins in the same subcellular compartment of the horizontal cell. Taken together, the strong expression of these two SNARE proteins in the processes and endings of horizontal cells at rod and cone terminals suggests that horizontal cell axons and dendrites are likely sites of exocytotic activity. PMID:17640443

The FgVps39-FgVam7-FgSso1 Complex Mediates Vesicle Trafficking and Is Important for the Development and Virulence of Fusarium graminearum.

PubMed

Li, Bing; Liu, Luping; Li, Ying; Dong, Xin; Zhang, Haifeng; Chen, Huaigu; Zheng, Xiaobo; Zhang, Zhengguang

2017-05-01

Vesicle trafficking is an important event in eukaryotic organisms. Many proteins and lipids transported between different organelles or compartments are essential for survival. These processes are mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, Rab-GTPases, and multisubunit tethering complexes such as class C core vacuole or endosome tethering and homotypic fusion or vacuole protein sorting (HOPS). Our previous study has demonstrated that FgVam7, which encodes a SNARE protein involving in vesicle trafficking, plays crucial roles in growth, asexual or sexual development, deoxynivalenol production, and pathogenicity in Fusarium graminearum. Here, the affinity purification approach was used to identify FgVam7-interacting proteins to explore its regulatory mechanisms during vesicle trafficking. The orthologs of yeast Vps39, a HOPS tethering complex subunit, and Sso1, a SNARE protein localized to the vacuole or endosome, were identified and selected for further characterization. In yeast two-hybrid and glutathione-S-transferase pull-down assays, FgVam7, FgVps39, and FgSso1 interacted with each other as a complex. The ∆Fgvps39 mutant generated by targeted deletion was significantly reduced in vegetative growth and asexual development. It failed to produce sexual spores and was defective in plant infection and deoxynivalenol production. Further cellular localization and cytological examinations suggested that FgVps39 is involved in vesicle trafficking from early or late endosomes to vacuoles in F. graminearum. Additionally, the ∆Fgvps39 mutant was defective in vacuole morphology and autophagy, and it was delayed in endocytosis. Our results demonstrate that FgVam7 interacts with FgVps39 and FgSso1 to form a unique complex, which is involved in vesicle trafficking and modulating the proper development of infection-related morphogenesis in F. graminearum.

Endoscopic full-thickness resection and defect closure in the colon.

PubMed

von Renteln, Daniel; Schmidt, Arthur; Vassiliou, Melina C; Rudolph, Hans-Ulrich; Caca, Karel

2010-06-01

Endoscopic full-thickness resection (eFTR) is a minimally invasive method for en bloc resection of GI lesions. The aim of this pilot study was to evaluate the feasibility of a grasp-and-snare technique for eFTR combined with an over-the-scope clip (OTSC) for defect closure. Nonsurvival animal study. Animal laboratory. Fourteen female domestic pigs. The eFTR was performed in porcine colons using a novel tissue anchor in combination with a standard monofilament snare and 14 mm OTSC. In the first group (n = 20), closure of the colonic defects with OTSC was attempted after the resection. In the second group (n = 8), an endoloop was used to secure the resection base before eFTR was performed. In the first group (n = 20), eFTR specimens ranged from 2.4 to 5.5 cm in diameter. Successful closure was achieved in 9 out of 20 cases. Mean burst pressure for OTSC closure was 29.2 mm Hg (range, 2-90; SD, 29.92). Injury to adjacent organs occurred in 3 cases. Lumen obstruction due to the OTSC closure occurred in 3 cases. In the second group (n = 8), the diameter of specimens ranged from 1.2 to 2.2 cm. Complete closure was achieved in all cases, with a mean burst pressure of 76.6 mm Hg (range, 35-120; SD, 31). Lumen obstruction due to the endoloop closure occurred in one case. No other complications or injuries were observed in the second group. Nonsurvival setting. Colonic eFTR using the grasp-and-snare technique is feasible in an animal model. Ligation of the resection base with an endoloop before eFTR seems to reduce complication rates and improve closure success and leak test results despite yielding smaller specimens. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

The Art of Snaring Dragons. Artificial Intelligence Memo Number 338. Revised.

ERIC Educational Resources Information Center

Cohen, Harvey A.

Several models for problem solving are discussed, and the idea of a heuristic frame is developed. This concept provides a description of the evolution of problem-solving skills in terms of the growth of the number of algorithms available and increased sophistication in their use. The heuristic frame model is applied to two sets of physical…

Winter bait stations as a multispecies survey tool

Treesearch

Lacy Robinson; Samuel A. Cushman; Michael K. Lucid

2017-01-01

Winter bait stations are becoming a commonly used technique for multispecies inventory and monitoring but a technical evaluation of their effectiveness is lacking. Bait stations have three components: carcass attractant, remote camera, and hair snare. Our 22,975 km2 mountainous study area was stratified with a 5 × 5 km sampling grid centered on northern Idaho and...

Developing Sight-Reading Skills on Mallet Percussion Instruments

ERIC Educational Resources Information Center

Fidyk, Steve

2009-01-01

Sight-reading while playing a mallet instrument can present serious obstacles for the developing percussionist. Many young players who have solid snare drum technique usually cite fear of playing the wrong note as the number-one hurdle to overcome in order to begin making real progress. Greg Byrne, associate director of bands at the University of…

Social Status of Adolescents with an Early Onset of Externalizing Behavior: The SNARE Study

ERIC Educational Resources Information Center

Franken, Aart; Harakeh, Zeena; Veenstra, Rene; Vollebergh, Wilma; Dijkstra, Jan Kornelis

2017-01-01

This study investigated the social status (i.e., popularity, likeability, and friendships) of adolescents with an early onset of externalizing behavior (i.e., alcohol use, tobacco use, and antisocial behavior). Building on Moffitt's dual-taxonomy model, it was hypothesized that early onset adolescents were more popular, but not necessarily more…

Predicting carnivore occurrence with noninvasive surveys and occupancy modeling

Treesearch

Robert Long; Therese Donovan; Paula MacKay; William Zielinski; Jeffrey Buzas

2011-01-01

Terrestrial carnivores typically have large home ranges and exist at low population densities, thus presenting challenges to wildlife researchers. We employed multiple, noninvasive survey methods—scat detection dogs, remote cameras, and hair snares—to collect detection–nondetection data for elusive American black bears (Ursus americanus), fishers...

Does the type and size of Amplatzer vascular plug affect the occlusion time of pulmonary arteriovenous malformations?

PubMed Central

Abdel-Aal, Ahmed Kamel; Massoud, Moustafa Omar; Elantably, Dina Mahmoud

2017-01-01

PURPOSE Occlusion time (OT) is an important factor in the treatment of pulmonary arteriovenous malformations (PAVMs) since it can lead to serious complications. The purpose of our study is to calculate the OT of Amplatzer vascular plug (AVP, St Jude Medical), and correlate it to the type of the device used (AVP or AVP 2) and the percent of device oversizing. Technical success rates and complications were also recorded. METHODS We retrospectively studied a total of 19 patients with 47 PAVMs who received percutaneous transcatheter embolization therapy using either AVP or AVP 2. We recorded the location, type, feeding artery diameter, AVP device used, and OT of each PAVM. We correlated the percent of device oversizing and the type of AVP with the OT. We also studied the rate of persistence of PAVM for both devices. RESULTS Forty-six (98%) of the PAVMs were simple. Device diameters ranged from 4.0–16.0 mm with device oversizing ranging between 14% and 120%. There was a statistically significant difference in the OT of AVP and AVP 2 (3 min 54 s vs. 5 min 30 s, P = 0.030). There was a weak positive correlation between OT and device oversizing for AVP (r=0.246, P = 0.324) and AVP 2 (r=0.261, P = 0.240). No major complications were identified. Immediate technical success rate was 100%. CONCLUSION The use of AVP 2, and increase in device oversizing were not associated with reduction in the OT of PAVMs. There was no reported difference in safety between the two devices, and no major complications were noted. PMID:27856403

[Reshaping the left Judkins catheter for a right coronary angiogram in the anomalous aortic origin of the right coronary: killing two birds with one left Judkins].

PubMed

Akgün, Taylan; Tanboğa, Ibrahim Halil; Oduncu, Vecih; Kurt, Mustafa; Cimen, Arif Oğuzhan; Bitigen, Atila

2012-09-01

Selective cannulation of the right coronary artery (RCA) in the anomalous aortic origin of the RCA is technically difficult and challenging. In this study, we tested the success of RCA cannulation with a reshaped left Judkins catheter in cases of difficult selective cannulation. The study population consisted of 837 consecutive patients (456 male, 381 female) that were admitted to our hospital with stable angina pectoris and acute coronary syndrome between October 1 and December 31, 2011. In cases where RCA cannulation was difficult, the 10 centimeter section of the left Judkins proximal to the secondary curve was reshaped by hand to form an inward slope. The secondary curve angle was increased to approximately 100 degrees and the primary curve angle was adjusted to 120 degrees. Then, we attempted to perform selective RCA cannulation. In 49 of the 837 patients, selective RCA cannulation was unsuccessful with the right Judkins catheter. In 42 of these 49 (86%) cases, the RCA was cannulated with the reshaped left Judkins. We failed to cannulate the right coronary in two cases with downward angulation, one with upward angulation, one with high take-off origin, and one with anterior origin. A multipurpose, internal mammary artery, left Amplatz 1, and right Amplatz 1 catheter were used for cannulation in these cases, respectively. There was no angina, nor were there electrocardiographic or hemodynamic changes during the procedure. In cases where the selective cannulation of the RCA is difficult, using a reshaped left Judkins may be a successful and cost-effective method of selective cannulation.

Periprocedural intracardiac echocardiography for left atrial appendage closure: a dual-center experience.

PubMed

Berti, Sergio; Paradossi, Umberto; Meucci, Francesco; Trianni, Giuseppe; Tzikas, Apostolos; Rezzaghi, Marco; Stolkova, Miroslava; Palmieri, Cataldo; Mori, Fabio; Santoro, Gennaro

2014-09-01

This dual-center study sought to demonstrate the utility and safety of intracardiac echocardiography (ICE) in providing adequate imaging guidance as an alternative to transesophageal echocardiography (TEE) during Amplatzer Cardiac Plug device implantation. Over 90% of intracardiac thrombi in atrial fibrillation originate from the left atrial appendage (LAA). Patients with contraindications to anticoagulation are potential candidates for LAA percutaneous occlusion. TEE is typically used to guide implantation. ICE-guided percutaneous LAA closure was performed in 121 patients to evaluate the following tasks typically achieved by TEE: assessment of the LAA dimension for device sizing; guidance of transseptal puncture; verification of the delivery sheath position; confirmation of location and stability of the device before and after release and continuous monitoring to detect procedural complications. In 51 consecutive patients, we compared the measurements obtained by ICE and fluoroscopy to choose the size of the device. The device was successfully implanted in 117 patients, yielding a technical success rate of 96.7%. Procedural success was achieved in 113 cases (93.4%). Four major adverse events (3 cardiac tamponades and 1 in-hospital transient ischemic attack) occurred. There was significant correlation in the measurements for device sizing assessed by angiography and ICE (r = 0.94, p < 0.0001). ICE imaging was able to perform the tasks typically provided by TEE during implantation of the Amplatzer Cardiac Plug device for LAA occlusion. Therefore, we provide evidence that the use of ICE offered accurate measurements of LAA dimension in order to select the correct device sizes. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Use of the Amplatzer Type 2 Plug for Flow Redirection in Failing Autogenous Hemodialysis Fistulae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bozkurt, Alper, E-mail: bozkurtalper@yahoo.com; Kırbaş, İsmail, E-mail: drismailk@yahoo.com; Kasapoglu, Benan, E-mail: benankasapoglu@hotmail.com

PurposeTo present our experience with redirecting the outflow of mature arteriovenous fistulae (AVFs) in patients with cannulation and/or suboptimal flow problems by percutaneous intervention using the Amplatzer Vascular Plug II (AVP II).MethodsWe retrospectively reviewed patients who presented with difficulty in cannulation and/or suboptimal flow in the puncture zone of the AVF and who underwent intervention using the AVP II to redirect the outflow through a better cannulation zone from March 2009 to November 2012. The mean survival rate of all AVFs was estimated, and the effects of patient age, sex, and AVF age on the AVF survival time were determined.ResultsInmore » total, 31 patients (17 male and 14 female) with a mean age of 57.8 years (range, 20–79 years) were included. In 2 patients, the AVF failed within the first 15 days because of rapid thrombosis. In 9 patients, the new AVF route was working effectively until unsalvageable thrombosis developed. One of the 31 patients died 9 months before the last radiologic evaluation. The new AVF route was still being used for dialysis in the remaining 19 patients. The mean AVF survival rate was 1,061.4 ± 139.4 days (range, 788–1,334 days). Patient age, sex, and AVF age did not affect the survival time.ConclusionWe suggest that the AVP II is useful for redirecting the outflow of AVFs with cannulation problems and suboptimal flow. Patency of existing AVFs may be extended, thereby extending surgery-free or catheter intervention-free survival period.« less

Occlusion of Arteriovenous Fistulas of In-Situ Saphenous Vein Bypass Grafts Using the Amplatzer Vascular Plug 4: Initial Experience

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libicher, Martin, E-mail: martin.libicher@uk-koeln.de; Reichert, V.; Schwabe, H.

2011-06-15

We examined the safety and efficacy of vessel occlusion of the Amplatzer Vascular Plug 4 (AVP-4) in patients with arteriovenous fistulas after in-situ saphenous vein bypass grafts. We treated 18 fistulas of seven patients (four women, mean {+-} standard deviation age 76 {+-} 7 years, range 63-88 years). All fistulas were detected within 14 days after surgery. Initial diagnosis and follow-up was established by sonography. We measured the diameter of the feeding vessel and the time of vessel occlusion after plug deployment. Additionally, we recorded procedure time and the dose area product. Additional interventional procedures were necessary in three patients.more » We successfully used 19 AVP-4 for occlusion of all fistulas without thromboembolic complications. There was no need for recapturing the device, and we did not observe dislocation. Mean occlusion time was 9.6 min (range 5-22 min). Mean diameter of the feeding vessels was 3.5 mm (range 2.6-5.1 mm). Plug sizes ranged from 4-8 mm (mean 5.5 mm) resulting in an oversizing of 33-88%. Mean procedure time for patients with and without additional intervention was 91 {+-} 38 min and 35 {+-} 18 min, respectively. Mean dose area product was 11,790 cGy/cm{sup 2} (range 1,850-23,500 cGy/cm{sup 2}). Permanent occlusion of the fistulas was confirmed by ultrasound after a mean follow-up of 4 months (1-6 months). Occlusion of arteriovenous fistulas with an AVP-4 seems to be effective and safe in patients with in-situ saphenous vein bypass grafts. The AVP-4 is well suited for this purpose because of the appropriate diameter of the feeding vessels.« less

Holmium:Yttrium Aluminum Garnet Laser and Guidewires: Is There a Durability Difference Among Guidewires Against Laser Energy? An In Vitro Experimental Study.

PubMed

Bagbanci, Sahin

2017-05-01

To evaluate the durability differences between five different type of guidewires against laser energy in an in vitro experimental ureteral model. The study was performed at the Department of Urology, Medicine Faculty of Ahi Evran University. An in vitro experimental ureteral model was created for the work; a silicon ureteral model in a saline-filled container. Experiments were performed on five different type of guidewires; ZIPwire, Sensor polytetrafluoroethylene (PTFE) Nitinol guidewire, Roadrunner ® PC wire guide, Amplatz Super Stiff, and Zebra Urologic Guidewire. These guidewires were grouped from one to five, respectively. Laser fibers were contacted to the guidewire, and laser energy was fired to the premarked tip and body parts in different adjustments. The breakage of the guidewires was detected only on the flexible tip parts in group 1a, group 1b, group 2a, group 2b, group 4a, and group 4b. The body parts of the guidewires were resistant to laser energy in all groups and did not break. The breakage of the guidewires occurred after 3 J × 10 Hz (30 W) experiment. Group 1a and 1b were different from group 2a, 2b, 4a, and 4b according to Kruskal-Wallis H test. The body parts of the guidewires in all study groups were resistant to laser energy. The tip parts of Zipwire ™ , Sensor ™ PTFE Nitinol, and Amplatz Super Stiff ™ guidewire should be kept away from the surgical field when the high power settings of the laser are being used. The body parts of the guidewires can be utilized in the surgical field safely.

Hybrid approach for closure of muscular ventricular septal defects

PubMed Central

Haponiuk, Ireneusz; Chojnicki, Maciej; Jaworski, Radoslaw; Steffek, Mariusz; Juscinski, Jacek; Sroka, Mariusz; Fiszer, Roland; Sendrowska, Aneta; Gierat-Haponiuk, Katarzyna; Maruszewski, Bohdan

2013-01-01

Background The complexity of ventricular septal defects in early infancy led to development of new mini-invasive techniques based on collaboration of cardiac surgeons with interventional cardiologists, called hybrid procedures. Hybrid therapies aim to combine the advantages of surgical and interventional techniques in an effort to reduce the invasiveness. The aim of this study was to present our approach with mVSD patients and initial results in the development of a mini-invasive hybrid procedure in the Gdansk Hybrid Heartlink Programme (GHHP) at the Department of Pediatric Cardiac Surgery, Pomeranian Centre of Traumatology in Gdansk, Poland. Material/Methods The group of 11 children with mVSDs was enrolled in GHHP and 6 were finally qualified to hybrid trans-ventricular mVSD device closure. Mean age at time of hybrid procedure was 8.22 months (range: from 2.7 to 17.8 months, SD=5.1) and mean body weight was 6.3 kg (range: from 3.4 to 7.5 kg, SD=1.5). Results The implants of choice were Amplatzer VSD Occluder and Amplatzer Duct Occluder II (AGA Med. Corp, USA). The position of the implants was checked carefully before releasing the device with both transesophageal echocardiography and epicardial echocardiography. All patients survived and their general condition improved. No complications occurred. The closure of mVSD was complete in all children. Conclusions Hybrid procedures of periventricular muscular VSD closure appear feasible and effective for patients with septal defects with morphology unsuitable for classic surgical or interventional procedures. The modern strategy of joint cardiac surgical and interventional techniques provides the benefits of close cooperation between cardiac surgeon and interventional cardiologist for selected patients in difficult clinical settings. PMID:23892911

[da Vinci surgical system].

PubMed

Watanabe, Gou; Ishikawa, Norihiro

2014-07-01

The da Vinci surgical system was developed by Intuitive Surgical Inc. in the United States as an endoscopic surgical device to assist remote control surgeries. In 1998, the Da Vinci system was first used for cardiothoracic procedures. Currently a combination of robot-assisted internal thoracic artery harvest together with coronary artery bypass grafting (CABG) through a mini-incision (ThoraCAB) or totally endoscopic procedures including anastomoses under robotic assistance (TECAB) are being conducted for the treatment of coronary artery diseases. With the recent advances in catheter interventions, hybrid procedures combining catheter intervention with ThoraCAB or TECAB are anticipated in the future.On the other hand, with the decrease in number of coronary artery bypass surgeries, the share of valvular surgeries is expected to increase in the future. Among them, mitral valvuloplasty for mitral regurgitation is anticipated to be conducted mainly by low-invasive procedures, represented by minimally invasive cardiac surgery( MICS) and robot-assisted surgery. Apart from the intrinsic good surgical view, robotic-assisted systems offer additional advantages of the availability of an amplified view and the easy to observe the mitral valve in the physiological position. Thus, robotic surgical surgeries that make complicated procedures easier are expected to accomplish further developments in the future. Furthermore, while the number of surgeries for atrial septal defects has decreased dramatically following the widespread use of Amplatzer septal occluder, robotic surgery may become a good indication for cases in which the Amplatzer device is not indicated. In Japan, clinical trial of the da Vinci robotic system for heart surgeries has been completed. Statutory approval of the da Vinci system for mitral regurgitation and atrial septal defects is anticipated in the next few years.

Embolization techniques for high-flow arteriovenous malformations with a dominant outflow vein.

PubMed

Conway, Allan M; Qato, Khalil; Drury, Jennifer; Rosen, Robert J

2015-04-01

The aim of this study was to assess the management and outcomes of arteriovenous malformations (AVMs) with a dominant outflow vein (DOV) treated with retrograde venous embolization. A retrospective review was performed from November 2010 to May 2014 on all patients with a high-flow AVM and associated DOV who underwent transvenous embolization of the DOV. Indications, techniques, complications, and outcomes were reviewed. Fourteen patients (five male; 36%) underwent transvenous embolization of high-flow AVMs with a DOV. Median age was 41.6 years (15.7-65.8 years). The AVM was located on an extremity in eight patients (57%) and in the pelvis in six patients (43%). The indication for the procedure was pain in 11 patients (79%), swelling in 3 patients (21%), a nonhealing wound in 1 patient (7%), and impotence in 1 patient (7%). The median number of prior procedures to treat the AVM was 2.5 (0-13). Transvenous embolization with coils was performed in 13 patients (93%). The Amplatzer vascular plug and Amplatzer septal occluder (St. Jude Medical, St. Paul, Minn) were used in four patients (29%). Concurrent percutaneous puncture embolization of the AVM nidus was used in seven patients (50%) and transcatheter arterial embolization in eight patients (57%). Technical angiographic success was seen in all patients. Five patients (36%) experienced a complete response to treatment, whereas eight (57%) experienced a partial response. Seven patients (50%) required further procedures for residual symptoms. AVMs with a DOV can be successfully treated by a transvenous approach. Percutaneous puncture embolization of the nidus or draining vein and transcatheter arterial embolization may assist in reducing flow. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Closure of patent ductus arteriosus in children, small infants, and premature babies with Amplatzer duct occluder II additional sizes: multicenter study.

PubMed

Sungur, Metin; Karakurt, Cemsit; Ozbarlas, Nazan; Baspinar, Osman

2013-08-01

To evaluate safety and efficacy of closure of patent ductus arteriosus (PDA) with Amplatzer duct occluder II Additional Sizes (ADO II AS) and to report early and midterm results of the device in children and very young symptomatic infants. Retrospective analysis of angiographic data of 60 children from four pediatric cardiology centers. The median patient age and weight were 6.5 (0.5-168) months and 6.8 (1.19-57) kg, respectively. In the study, 26 children had a body weight of ≤ 6 kg. Of these 26 children, 9 had a body weight of ≤ 3 kg. The median narrowest diameter of PDA was 2 (1.2-4) mm. Ductal anatomy was Type A in 29, Type B in 2, Type C in 11, Type D in 1, and Type E in 16 patients, and a residual PDA after surgery in 1 patient. Closure with ADO II AS was achieved in 58 (96.6%) of 60 attempted cases. In two infants, the device was not released because of significant residual shunt. ADO II was used in one, and the other was sent to surgery. Complete closure was observed in all ADO II AS deployed children by the next day on echocardiography. Median follow-up was 12 (1-18) months. Neither death nor any major complications occurred. Our study shows that closure of medium and small sized PDA by using ADO II AS device is effective and safe in children. The use of the device will expand the field of application of PDA closure in small infants. © 2013 Wiley Periodicals, Inc.

Patent ductus arteriosus closure using an Amplatzer(™) ventricular septal defect closure device.

PubMed

Fernando, Rajeev; Koranne, Ketan; Loyalka, Pranav; Kar, Biswajit; Gregoric, Igor

2013-01-01

The ductus arteriosus originates from the persistence of the distal portion of the left sixth aortic arch. It connects the descending aorta (immediately distal to the left subclavian artery) to the roof of the main pulmonary artery, near the origin of the left pulmonary artery. Persistence of the duct beyond 48 h after birth is abnormal and results in patent ductus arteriosus (PDA). PDA is rare in adults because it is usually discovered and treated in childhood. Mechanical closure remains the definitive therapy because the patency of ductus arteriosus may lead to multiple complications, depending on the size and flow through the ductus. PDA closure is indicated in patients with symptoms and evidence of left heart enlargement, and in patients with elevated pulmonary pressures when reversal is possible. Transcatheter closure is the preferred technique in adults because it avoids sternotomy, reduces the length of hospital stay and is associated with fewer complications compared with surgery. First demonstrated in 1967, both the technique and the occluder devices used have since evolved. However, designing an ideal PDA occluder has been a challenge due to the variability in size, shape and orientation of PDAs. The present article describes a case involving a 35-year-old woman who presented to the Center for Advanced Heart Failure (Houston, USA) with congestive heart failure due to a large PDA, which was successfully occluded using an Amplatzer (St Jude Medical, USA) muscular ventricular septal defect closure device. The wider waist and dual-retention discs of these ventricular septal defect closure devices may be important factors to consider in the future development of devices for the occlusion of large PDAs.

Transcatheter closure of ventricular septal defects with nitinol wire occluders of type patent ductus arteriosus.

PubMed

Wierzyk, Arkadiusz; Szkutnik, Małgorzata; Fiszer, Roland; Banaszak, Paweł; Pawlak, Szymon; Białkowski, Jacek

2014-01-01

Ventricular septal defects closure (VSD) depending on the anatomy and clinical setting can be performed surgically or by a hybrid and transcatheter approach. Two cases of children with VSD will be presented. Patients' defects were closed with various types of occluders made of nitinol wire mesh occluder, patent ductus arteriosus (PDA) type. The first case was a 2.5-year-old boy after cardiosurgical correction of tetralogy of Fallot (TOF). After the procedure, a significant haemodynamic residual VSD was observed, which was not successfully closed during the subsequent reoperation. Despite pharmacological treatment, symptoms of heart failure were observed in this patient. In echocardiographic images the residual VSD was presented as a tunnel-like dissection of the ventricular septum (length 6 mm and diameter 3.4 mm). The defect was closed via arterial access with an Amplatzer Duct Occluder II (ADO II). The procedure was successfully performed without any medical complications. In this child, a significant shunt reduction and a noticeable improvement in the patient's clinical status and diminished symptoms of heart failure were noticed. The second patient was a 4-year-old girl suffering from a multi-perforated perimembranous VSD accompanied by a ventricular septal defect with aneurysm. The defect was closed by a venous approach with a PDA Cardio-O-Fix occluder (very similar to ADO I). No short-term or long-term complications were visible during or after the procedure. Only a mild residual shunt through the VSD was observed 6 months afterwards. Transcatheter VSD closure with a proper morphology, with occluders of type Amplatzer Duct Occluder ADO I or ADO II, constitutes a safe and effective therapeutic alternative.

Application of Cardio-O-Fix occluders for transcatheter closure of patent ductus arteriosus and interatrial communications: Preliminary experience.

PubMed

Białkowski, Jacek; Szkutnik, Małgorzata; Fiszer, Roland; Głowacki, Jan; Banaszak, Paweł; Zembala, Marian

2010-01-01

Transcatheter treatment has become the method of choice for treating many heart defects. Recently, Cardio-O-Fix occluder (COF) - a new, self-expandable nitinol wire-mesh device very similar to the Amplatzer device - has been introduced into clinical practice. To the best of our knowledge, this is the first publication related to its application. Five patients aged from six months to 69 years were included in the study: two with atrial septal defect (ASD), one with patent foramen ovale (PFO) after cryptogenic stroke, and two with patent ductus arteriosus (PDA). These latter two comprised one six month old infant with co-existent hypertrophied cardiomyopathy, and a 53 year-old woman with recanalized PDA after previous ligation. All were treated percutaneously with COF. There was no preliminary patient selection. The only limitation was the size of the devices in our possession (16 and 22 mm ASD COF, 25 PFO COF, 4/6 and 6/8 PDA COF). The implantation technique was the same as previously described for Amplatzer occluders. All procedures were finished successfully with complete closure of the shunt. No complications were observed during a six month follow-up. In the child with PDA, we observed decrease of gradient from 80 to 60 mm Hg in hypertrophied left ventricular outflow tract, although a small protrusion of PDA-COF device was noted in the descending aorta (8 mm Hg gradient in ECHO). In the patient with recanalized PDA, the procedure was performed after arterio-venous loop creation. Mean fluoroscopy time was 4.4 (range from 1.6 to 11) minutes. Our preliminary experience indicates that the application of Cardio-O-Fix devices is safe and effective.

A novel percutaneous nephrolithotomy (PCNL) set: The 'Economical One-shot PCNL Set' (Ecoset).

PubMed

Penbegul, Necmettin; Dede, Onur; Daggulli, Mansur; Hatipoglu, Namik Kemal; Bozkurt, Yasar

2017-09-01

To suggest a novel disposable percutaneous nephrolithotomy (PCNL) set that we named the ' Ec onomical O ne-shot PCNL Set ' (Ecoset), which consists of a single 30-F dilator, 30-F sheath, and 8-F polyurethane dilator, as use of a 'one-shot' dilatation technique during PCNL is becoming widespread. The medical records of 42 patients with kidney stones who had undergone 'one-shot' PCNL from February 2014 to June 2016 were retrospectively reviewed and analysed. Demographic data, as well as the stone size, radiation exposure time, operation time, hospitalisation duration, rate of treatment success and complications, were recorded. The mean (SD, range) age of the patients was 44.43 (16.54, 11-72) years. The mean (SD) stone size was 35.12 (17.53) mm. The mean (SD) operation time was 54.58 (22.24) min. The mean (SD) fluoroscopic screening time was limited to 154.72 (117.48) s. Treatment success was achieved in 32 (76%) patients. The mean (SD) hospital stay was 3.09 (0.75) days. None of the patients had any major complications. Bleeding requiring blood transfusion was required in three patients. The cost of a disposable dilatation set for a single PCNL operation with a balloon set, a standard Amplatz set, or an Ecoset is ∼$137, $120, or $27 (American dollars), respectively. The one-shot dilatation technique using the Ecoset for PCNL can be feasibly, safely, and effectively performed in almost every adult patient. The Amplatz dilator set and balloon dilator set have the disadvantage of relatively high cost, whereas the Ecoset is the cheapest 'disposable set' that can be used during PCNL surgery.

Practice advisory: Recurrent stroke with patent foramen ovale (update of practice parameter)

PubMed Central

Messé, Steven R.; Gronseth, Gary; Kent, David M.; Kizer, Jorge R.; Homma, Shunichi; Rosterman, Lee; Kasner, Scott E.

2016-01-01

Objective: To update the 2004 American Academy of Neurology guideline for patients with stroke and patent foramen ovale (PFO) by addressing whether (1) percutaneous closure of PFO is superior to medical therapy alone and (2) anticoagulation is superior to antiplatelet therapy for the prevention of recurrent stroke. Methods: Systematic review of the literature and structured formulation of recommendations. Conclusions: Percutaneous PFO closure with the STARFlex device possibly does not provide a benefit in preventing stroke vs medical therapy alone (risk difference [RD] 0.13%, 95% confidence interval [CI] −2.2% to 2.0%). Percutaneous PFO closure with the AMPLATZER PFO Occluder possibly decreases the risk of recurrent stroke (RD −1.68%, 95% CI −3.18% to −0.19%), possibly increases the risk of new-onset atrial fibrillation (AF) (RD 1.64%, 95% CI 0.07%–3.2%), and is highly likely to be associated with a procedural complication risk of 3.4% (95% CI 2.3%–5%). There is insufficient evidence to determine the efficacy of anticoagulation compared with antiplatelet therapy in preventing recurrent stroke (RD 2%, 95% CI −21% to 25%). Recommendations: Clinicians should not routinely offer percutaneous PFO closure to patients with cryptogenic ischemic stroke outside of a research setting (Level R). In rare circumstances, such as recurrent strokes despite adequate medical therapy with no other mechanism identified, clinicians may offer the AMPLATZER PFO Occluder if it is available (Level C). In the absence of another indication for anticoagulation, clinicians may routinely offer antiplatelet medications instead of anticoagulation to patients with cryptogenic stroke and PFO (Level C). PMID:27466464

Practice advisory: Recurrent stroke with patent foramen ovale (update of practice parameter): Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology.

PubMed

Messé, Steven R; Gronseth, Gary; Kent, David M; Kizer, Jorge R; Homma, Shunichi; Rosterman, Lee; Kasner, Scott E

2016-08-23

To update the 2004 American Academy of Neurology guideline for patients with stroke and patent foramen ovale (PFO) by addressing whether (1) percutaneous closure of PFO is superior to medical therapy alone and (2) anticoagulation is superior to antiplatelet therapy for the prevention of recurrent stroke. Systematic review of the literature and structured formulation of recommendations. Percutaneous PFO closure with the STARFlex device possibly does not provide a benefit in preventing stroke vs medical therapy alone (risk difference [RD] 0.13%, 95% confidence interval [CI] -2.2% to 2.0%). Percutaneous PFO closure with the AMPLATZER PFO Occluder possibly decreases the risk of recurrent stroke (RD -1.68%, 95% CI -3.18% to -0.19%), possibly increases the risk of new-onset atrial fibrillation (AF) (RD 1.64%, 95% CI 0.07%-3.2%), and is highly likely to be associated with a procedural complication risk of 3.4% (95% CI 2.3%-5%). There is insufficient evidence to determine the efficacy of anticoagulation compared with antiplatelet therapy in preventing recurrent stroke (RD 2%, 95% CI -21% to 25%). Clinicians should not routinely offer percutaneous PFO closure to patients with cryptogenic ischemic stroke outside of a research setting (Level R). In rare circumstances, such as recurrent strokes despite adequate medical therapy with no other mechanism identified, clinicians may offer the AMPLATZER PFO Occluder if it is available (Level C). In the absence of another indication for anticoagulation, clinicians may routinely offer antiplatelet medications instead of anticoagulation to patients with cryptogenic stroke and PFO (Level C). © 2016 American Academy of Neurology.

Estimating abundance and survival in the endangered Point Arena Mountain beaver using noninvasive genetic methods

Treesearch

William J. Zielinski; Fredrick V. Schlexer; T. Luke George; Kristine L. Pilgrim; Michael K. Schwartz

2013-01-01

The Point Arena mountain beaver (Aplodontia rufa nigra) is federally listed as an endangered subspecies that is restricted to a small geographic range in coastal Mendocino County, California. Management of this imperiled taxon requires accurate information on its demography and vital rates. We developed noninvasive survey methods, using hair snares to sample DNA and to...

CNC Skills Help Carpentry Students Snare High-Paying Jobs

ERIC Educational Resources Information Center

Panella, John

2007-01-01

Wages of entry-level carpenters have been driven down along with those of many other non-professional occupations in recent years. If carpenters stay in the field, they typically advance slowly over the years until they reach the level of master craftsman, perhaps by the time they reach the age of 40. However, technology is having a major impact…

Retrieval of an intra-cardiac embolised very long wire via transhepatic access from a war victim child.

PubMed

Baspinar, Osman; Sahin, Derya A; Yildirim, Ali

2016-04-01

We present the case report of a war victim child with severe burn scars, orthopnoea, and dyspnoea due to diffuse pulmonary thromboembolism. During ICU stay, a central venous catheter's 45-mm wire embolised into the heart. The embolised wire was successfully removed via transhepatic access through the creation of an artificial simple snare.

Red mud flocculation process in alumina production

NASA Astrophysics Data System (ADS)

Fedorova, E. R.; Firsov, A. Yu

2018-05-01

The process of thickening and washing red mud is a gooseneck of alumina production. The existing automated systems of the thickening process control involve stabilizing the parameters of the primary technological circuits of the thickener. The actual direction of scientific research is the creation and improvement of models and systems of the thickening process control by model. But the known models do not fully consider the presence of perturbing effects, in particular the particle size distribution in the feed process, distribution of floccules by size after the aggregation process in the feed barrel. The article is devoted to the basic concepts and terms used in writing the population balance algorithm. The population balance model is implemented in the MatLab environment. The result of the simulation is the particle size distribution after the flocculation process. This model allows one to foreseen the distribution range of floccules after the process of aggregation of red mud in the feed barrel. The mud of Jamaican bauxite was acting as an industrial sample of red mud; Cytec Industries of HX-3000 series with a concentration of 0.5% was acting as a flocculant. When simulating, model constants obtained in a tubular tank in the laboratories of CSIRO (Australia) were used.

Exocytosis of Neutrophil Granule Subsets and Activation of Prolyl Isomerase 1 are required for Respiratory Burst Priming

PubMed Central

McLeish, Kenneth R.; Uriarte, Silvia M.; Tandon, Shweta; Creed, Timothy M.; Le, Junyi; Ward, Richard A.

2013-01-01

This study tested the hypothesis that priming the neutrophil respiratory burst requires both granule exocytosis and activation of the prolyl isomerase, Pin1. Fusion proteins containing the TAT cell permeability sequence and either the SNARE domain of syntaxin-4 or the N-terminal SNARE domain of SNAP-23 were used to examine the role of granule subsets in TNF-mediated respiratory burst priming using human neutrophils. Concentration-inhibition curves for exocytosis of individual granule subsets and for priming of fMLF-stimulated superoxide release and phagocytosis-stimulated H2O2 production were generated. Maximal inhibition of priming ranged from 72% to 88%. Linear regression lines for inhibition of priming versus inhibition of exocytosis did not differ from the line of identity for secretory vesicles and gelatinase granules, while the slopes or the y-intercepts were different from the line of identity for specific and azurophilic granules. Inhibition of Pin1 reduced priming by 56%, while exocytosis of secretory vesicles and specific granules was not affected. These findings indicate that exocytosis of secretory vesicles and gelatinase granules and activation of Pin1 are independent events required for TNF-mediated priming of neutrophil respiratory burst. PMID:23363774

Synaptic Vesicle Mobility and Presynaptic F-Actin Are Disrupted in a N-ethylmaleimide–sensitive Factor Allele of Drosophila

PubMed Central

Nunes, Paula; Haines, Nicola; Kuppuswamy, Venkat; Fleet, David J.

2006-01-01

N-ethylmaleimide sensitive factor (NSF) can dissociate the soluble NSF attachment receptor (SNARE) complex, but NSF also participates in other intracellular trafficking functions by virtue of SNARE-independent activity. Drosophila that express a neural transgene encoding a dominant-negative form of NSF2 show an 80% reduction in the size of releasable synaptic vesicle pool, but no change in the number of vesicles in nerve terminal boutons. Here we tested the hypothesis that vesicles in the NSF2 mutant terminal are less mobile. Using a combination of genetics, pharmacology, and imaging we find a substantial reduction in vesicle mobility within the nerve terminal boutons of Drosophila NSF2 mutant larvae. Subsequent analysis revealed a decrease of filamentous actin in both NSF2 dominant-negative and loss-of-function mutants. Lastly, actin-filament disrupting drugs also decrease vesicle movement. We conclude that a factor contributing to the NSF mutant phenotype is a reduction in vesicle mobility, which is associated with decreased presynaptic F-actin. Our data are consistent with a model in which actin filaments promote vesicle mobility and suggest that NSF participates in establishing or maintaining this population of actin. PMID:16914524

LAMP-2 is required for incorporating syntaxin-17 into autophagosomes and for their fusion with lysosomes

PubMed Central

Peschel, Andrea; Langer, Brigitte; Gröger, Marion; Rees, Andrew; Kain, Renate

2016-01-01

ABSTRACT Autophagy is an evolutionarily conserved process used for removing surplus and damaged proteins and organelles from the cytoplasm. The unwanted material is incorporated into autophagosomes that eventually fuse with lysosomes, leading to the degradation of their cargo. The fusion event is mediated by the interaction between the Qa-SNARE syntaxin-17 (STX17) on autophagosomes and the R-SNARE VAMP8 on lysosomes. Cells deficient in lysosome membrane-associated protein-2 (LAMP-2) have increased numbers of autophagosomes but the underlying mechanism is poorly understood. By transfecting LAMP-2-deficient and LAMP-1/2­-double-deficient mouse embryonic fibroblasts (MEFs) with a tandem fluorescent-tagged LC3 we observed a failure of fusion between the autophagosomes and the lysosomes that could be rescued by complementation with LAMP-2A. Although we observed no change in expression and localization of VAMP8, its interacting partner STX17 was absent from autophagosomes of LAMP-2-deficient cells. Thus, LAMP-2 is essential for STX17 expression by the autophagosomes and this absence is sufficient to explain their failure to fuse with lysosomes. The results have clear implications for situations associated with a reduction of LAMP-2 expression. PMID:27628032

Computer-aided identification, synthesis, and biological evaluation of novel inhibitors for botulinum neurotoxin serotype A

DOE PAGES

Teng, Y. G.; Berger, W. T.; Nesbitt, N. M.; ...

2015-07-27

Botulinum neurotoxins (BoNTs) are among the most potent biological toxin known to humans, and are classified as Category A bioterrorism agents by the Centers for Disease Control and prevention (CDC). There are seven known BoNT serotypes (A-G) which have been thus far identified in literature. BoNTs have been shown to block neurotransmitter release by cleaving proteins of the soluble NSF attachment protein receptor (SNARE) complex. Disruption of the SNARE complex precludes motor neuron failure which ultimately results in flaccid paralysis in humans and animals. Currently, there are no effective therapeutic treatments against the neurotoxin light chain (LC) after translocation intomore » the cytosols of motor neurons. In this work, high-throughput virtual screening was employed to screen a library of commercially available compounds from ZINC database against BoNT/A-LC. Among the hit compounds from the in-silico screening, two lead compounds were identified and found to have potent inhibitory activity against BoNT/A-LC in vitro, as well as in Neuro-2a cells. A few analogues of the lead compounds were synthesized and their potency examined. One of these analogues showed an enhanced activity than the lead compounds« less

Autoinhibition of Munc18-1 modulates synaptobrevin binding and helps to enable Munc13-dependent regulation of membrane fusion.

PubMed

Sitarska, Ewa; Xu, Junjie; Park, Seungmee; Liu, Xiaoxia; Quade, Bradley; Stepien, Karolina; Sugita, Kyoko; Brautigam, Chad A; Sugita, Shuzo; Rizo, Josep

2017-05-06

Munc18-1 orchestrates SNARE complex assembly together with Munc13-1 to mediate neurotransmitter release. Munc18-1 binds to synaptobrevin, but the relevance of this interaction and its relation to Munc13 function are unclear. NMR experiments now show that Munc18-1 binds specifically and non-specifically to synaptobrevin. Specific binding is inhibited by a L348R mutation in Munc18-1 and enhanced by a D326K mutation designed to disrupt the 'furled conformation' of a Munc18-1 loop. Correspondingly, the activity of Munc18-1 in reconstitution assays that require Munc18-1 and Munc13-1 for membrane fusion is stimulated by the D326K mutation and inhibited by the L348R mutation. Moreover, the D326K mutation allows Munc13-1-independent fusion and leads to a gain-of-function in rescue experiments in Caenorhabditis elegans unc-18 nulls. Together with previous studies, our data support a model whereby Munc18-1 acts as a template for SNARE complex assembly, and autoinhibition of synaptobrevin binding contributes to enabling regulation of neurotransmitter release by Munc13-1.

A bioeconomic analysis of bushmeat hunting

PubMed Central

Damania, R.; Milner-Gulland, E.J.; Crookes, D.J.

2005-01-01

Unsustainable bushmeat hunting is a major threat to mammal species, particularly in West/Central Africa. We developed a multispecies dynamic simulation model of hunter behaviour, parameterized using data from the Ashanti region, Ghana. The model distinguishes between two hunting techniques, snaring and gun hunting. We analyse the impact of key economic parameters on off-takes. Economic incentives determine the effort devoted to hunting, the choice of hunting technique, and the species that are consumed domestically or traded in markets. These factors, together with the growth rates and catchabilities of hunted species, determine the ecological impact of hunting. The results suggest that increased bushmeat prices are likely to lead to a switch from snaring, which is cheaper but less efficient, to gun hunting, with a consequent impact on vulnerable species. Increases in agricultural prices have an ambiguous effect on hunter behaviour, depending on the balance between incentives to invest in agriculture and increased consumption as incomes improve. Penalties are more effective if they target bushmeat sales, rather than the act of hunting. This model represents a step forward because it explicitly considers bushmeat as a component of the household economy. This has important implications as regards the development of policies to conserve species hunted for bushmeat. PMID:15705550

Resident CAPS on dense-core vesicles docks and primes vesicles for fusion

PubMed Central

Kabachinski, Greg; Kielar-Grevstad, D. Michelle; Zhang, Xingmin; James, Declan J.; Martin, Thomas F. J.

2016-01-01

The Ca2+-dependent exocytosis of dense-core vesicles in neuroendocrine cells requires a priming step during which SNARE protein complexes assemble. CAPS (aka CADPS) is one of several factors required for vesicle priming; however, the localization and dynamics of CAPS at sites of exocytosis in live neuroendocrine cells has not been determined. We imaged CAPS before, during, and after single-vesicle fusion events in PC12 cells by TIRF micro­scopy. In addition to being a resident on cytoplasmic dense-core vesicles, CAPS was present in clusters of approximately nine molecules near the plasma membrane that corresponded to docked/tethered vesicles. CAPS accompanied vesicles to the plasma membrane and was present at all vesicle exocytic events. The knockdown of CAPS by shRNA eliminated the VAMP-2–dependent docking and evoked exocytosis of fusion-competent vesicles. A CAPS(ΔC135) protein that does not localize to vesicles failed to rescue vesicle docking and evoked exocytosis in CAPS-depleted cells, showing that CAPS residence on vesicles is essential. Our results indicate that dense-core vesicles carry CAPS to sites of exocytosis, where CAPS promotes vesicle docking and fusion competence, probably by initiating SNARE complex assembly. PMID:26700319

Vascular plugs - A key companion to Interventionists - 'Just Plug it'.

PubMed

Ramakrishnan, Sivasubramanian

2015-01-01

Vascular plugs are ideally suited to close extra-cardiac, high flowing vascular communications. The family of vascular plugs has expanded. Vascular plugs in general have a lower profile and the newer variants can be delivered even through a diagnostic catheter. These features make them versatile and easy to use. The Amplatzer vascular plugs are also used for closing intracardiac defects including coronary arterio-venous fistula and paravalvular leakage in an off-label fashion. In this review, the features of currently available vascular plugs are reviewed along with tips and tricks of using them in the cardiac catheterization laboratory. Copyright © 2015. Published by Elsevier B.V.

Wild cats of the Sky Islands: a summary of monitoring efforts using noninvasive techniques

Treesearch

Lisa Haynes; Zoe Hackl; Melanie Culver

2005-01-01

A variety of efforts are taking place to detect, inventory, and monitor the wild felids (pumas, bobcats, jaguars, and ocelots) of the Madrean Archipelago. Researchers are using a suite of noninvasive methods, including infrared-triggered photography, DNA analysis of scat and hair (collected from “hair snares”), and old-fashioned tracking and sign searches. These...

Percutaneous retrieval of centrally embolized fragments of central venous access devices or knotted Swan-Ganz catheters. Clinical report of 14 retrievals with detailed angiographic analysis and review of procedural aspects

PubMed Central

Chmielak, Zbigniew; Dębski, Artur; Kępka, Cezary; Rudziński, Piotr N.; Bujak, Sebastian; Skwarek, Mirosław; Kurowski, Andrzej; Dzielińska, Zofia; Demkow, Marcin

2016-01-01

Introduction Totally implantable venous access systems (TIVAS), Swan-Ganz (SG) and central venous catheters (CVC) allow easy and repetitive entry to the central cardiovascular system. Fragments of them may be released inadvertently into the cardiovascular system during their insertion or as a result of mechanical complications encountered during long-term utilization. Aim To present results of percutaneous retrieval of embolized fragments of central venous devices or knotted SG and review the procedural aspects with a series of detailed angiographies. Material and methods Between January 2003 and December 2012 there were 14 (~0.025%) successful retrievals in 13 patients (44 ±16 years, 15% females) of embolized fragments of TIVAS (n = 10) or CVC (n = 1) or of dislodged guide-wires (n = 2) or knotted SG (n = 1). Results Foreign bodies with the forward end located in the right ventricle (RV), as well as those found in the pulmonary artery (PA), often required repositioning with a pigtail catheter as compared to those catheter fragments which were located in the right atrium (RA) and/or great vein and possessed an accessible free end allowing their direct ensnarement with the loop snare (57.0% (4/7) vs. 66.7% (2/3) vs. 0.0% (0/3); p = 0.074 respectively). Procedure duration was 2–3 times longer among catheters retrieved from the PA than among those with the forward edge located in the RV or RA (30 (18–68) vs. 13.5 (11–37) vs. 8 min (8–13); p = 0.054 respectively). The SG catheter knotted in the vena cava superior (VCS) was encircled with the loop snare introduced transfemorally, subsequently cut at its skin entrance and then pulled down inside the 14 Fr vascular sheath. Conclusions By using the pigtail catheter and the loop snare, it is feasible to retrieve centrally embolized fragments or knotted central venous access devices. PMID:27279874

Congenital intrahepatic portosystemic venous shunt and liver mass in a child patient: successful endovascular treatment with an amplatzer vascular plug (AVP).

PubMed

Lee, Sae Ah; Lee, Young Seok; Lee, Kun Song; Jeon, Gyeong Sik

2010-01-01

A congenital intrahepatic portosystemic shunt is a rare anomaly; but, the number of diagnosed cases has increased with advanced imaging tools. Symptomatic portosystemic shunts, especially those that include hyperammonemia, should be treated; and various endovascular treatment methods other than surgery have been reported. Hepatic masses with either an intra- or extrahepatic shunt also have been reported, and the mass is another reason for treatment. Authors report a case of a congenital intrahepatic portosystemic shunt with a hepatic mass that was successfully treated using a percutaneous endovascular approach with vascular plugs. By the time the first short-term follow-up was conducted, the hepatic mass had disappeared.

How Best to Remove the Snare from the Pair: Construction and Cognitive Load Hypotheses

ERIC Educational Resources Information Center

Igo, L. Brent; Kiewra, Kenneth A.; Zumbrunn, Sharon K.; Kirschbaum, Allison L.

2007-01-01

Students (N = 124) viewed 14 timed Web pages that distinguished 14 confusing word pairs. In a 2 x 2 factorial design, the authors gave all of the students matrices containing representational pictures for each pair of words, as well as examples of each word in use. One factor in the design was the absence or presence of rules of usage for each…

Rice by Weight, Other Produce by Bulk, and Snared Iguanas at So Much Per One. A Talk on Measurement Standards and on Metric Conversion.

ERIC Educational Resources Information Center

Allen, Harold Don

This script for a short radio broadcast on measurement standards and metric conversion begins by tracing the rise of the metric system in the international marketplace. Metric units are identified and briefly explained. Arguments for conversion to metric measures are presented. The history of the development and acceptance of the metric system is…

Rational Design of Therapeutic and Diagnostic Against Botulinum Neurotoxin

DTIC Science & Technology

2006-12-01

serotypes A, C, and E cleave SNAP-25; and serotype C cleaves syntaxin. Without acetylcholine release, the muscle is unable to contract . (after [24...binds to acetylcholine receptors on muscle cells for normal nerve impulse and muscle contraction . Cleavage of the neuronal SNARE complex proteins...A., Williams, T.A., Chauvet, M., and Corvol, P . (1997). Substrate dependence of angiotensin I – converting enzyme inhibition: captopril displays a

Assessing the potential threat landscape of a proposed reintroduction site for carnivores.

PubMed

Page, Samantha K; Parker, Daniel M; Peinke, Dean M; Davies-Mostert, Harriet T

2015-01-01

This study provides a framework to assess the feasibility of reintroducing carnivores into an area, using African wild dogs (Lycaon pictus) as an example. The Great Fish River Nature Reserve in the Eastern Cape Province, South Africa, has been identified as a potential reserve to reintroduce wild dogs, and we applied this framework to provide a threat assessment of the surrounding area to determine potential levels of human-wildlife conflict. Although 56% of neighbouring landowners and local communities were positive about a wild dog reintroduction, data collected from questionnaire surveys revealed that human-wild dog conflict is a potential threat to wild dog survival in the area. Additional potential threats include diseases, snaring, poaching and hunting wild dogs for the use of traditional medicine. A threat index was developed to establish which properties harboured the greatest threats to wild dogs. This index was significantly influenced by the respondent's first language (isiXhosa had more positive indices), education level (poorer education was synonymous with more positive threat indices), land use (wildlife ranching being the most negative) and land tenure (community respondents had more positive indices than private landowners). Although threats are present, they can be effectively mitigated through strategies such as carnivore education programs, vaccination campaigns and anti-snare patrols to promote a successful reintroduction of this endangered canid.

Physiological Roles of Plant Post-Golgi Transport Pathways in Membrane Trafficking.

PubMed

Uemura, Tomohiro

2016-10-01

Membrane trafficking is the fundamental system through which proteins are sorted to their correct destinations in eukaryotic cells. Key regulators of this system include RAB GTPases and soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs). Interestingly, the numbers of RAB GTPases and SNAREs involved in post-Golgi transport pathways in plant cells are larger than those in animal and yeast cells, suggesting that plants have evolved unique and complex post-Golgi transport pathways. The trans-Golgi network (TGN) is an important organelle that acts as a sorting station in the post-Golgi transport pathways of plant cells. The TGN also functions as the early endosome, which is the first compartment to receive endocytosed proteins. Several endocytosed proteins on the plasma membrane (PM) are initially targeted to the TGN/EE, then recycled back to the PM or transported to the vacuole for degradation. The recycling and degradation of the PM localized proteins is essential for the development and environmental responses in plant. The present review describes the post-Golgi transport pathways that show unique physiological functions in plants. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Hierarchical models for estimating density from DNA mark-recapture studies

USGS Publications Warehouse

Gardner, B.; Royle, J. Andrew; Wegan, M.T.

2009-01-01

Genetic sampling is increasingly used as a tool by wildlife biologists and managers to estimate abundance and density of species. Typically, DNA is used to identify individuals captured in an array of traps ( e. g., baited hair snares) from which individual encounter histories are derived. Standard methods for estimating the size of a closed population can be applied to such data. However, due to the movement of individuals on and off the trapping array during sampling, the area over which individuals are exposed to trapping is unknown, and so obtaining unbiased estimates of density has proved difficult. We propose a hierarchical spatial capture-recapture model which contains explicit models for the spatial point process governing the distribution of individuals and their exposure to (via movement) and detection by traps. Detection probability is modeled as a function of each individual's distance to the trap. We applied this model to a black bear (Ursus americanus) study conducted in 2006 using a hair-snare trap array in the Adirondack region of New York, USA. We estimated the density of bears to be 0.159 bears/km2, which is lower than the estimated density (0.410 bears/km2) based on standard closed population techniques. A Bayesian analysis of the model is fully implemented in the software program WinBUGS.

LAMP-2 is required for incorporating syntaxin-17 into autophagosomes and for their fusion with lysosomes.

PubMed

Hubert, Virginie; Peschel, Andrea; Langer, Brigitte; Gröger, Marion; Rees, Andrew; Kain, Renate

2016-10-15

Autophagy is an evolutionarily conserved process used for removing surplus and damaged proteins and organelles from the cytoplasm. The unwanted material is incorporated into autophagosomes that eventually fuse with lysosomes, leading to the degradation of their cargo. The fusion event is mediated by the interaction between the Qa-SNARE syntaxin-17 (STX17) on autophagosomes and the R-SNARE VAMP8 on lysosomes. Cells deficient in lysosome membrane-associated protein-2 (LAMP-2) have increased numbers of autophagosomes but the underlying mechanism is poorly understood. By transfecting LAMP-2-deficient and LAMP-1/2--double-deficient mouse embryonic fibroblasts (MEFs) with a tandem fluorescent-tagged LC3 we observed a failure of fusion between the autophagosomes and the lysosomes that could be rescued by complementation with LAMP-2A. Although we observed no change in expression and localization of VAMP8, its interacting partner STX17 was absent from autophagosomes of LAMP-2-deficient cells. Thus, LAMP-2 is essential for STX17 expression by the autophagosomes and this absence is sufficient to explain their failure to fuse with lysosomes. The results have clear implications for situations associated with a reduction of LAMP-2 expression. © 2016. Published by The Company of Biologists Ltd.

PI(4,5)P2-binding effector proteins for vesicle exocytosis

PubMed Central

Martin, Thomas F. J.

2014-01-01

PI(4,5)P2 participates directly in priming and possibly fusion steps of Ca2+-triggered vesicle exocytosis. High concentration nanodomains of PI(4,5)P2 reside on the plasma membrane of neuroendocrine cells. A subset of vesicles that co-localize with PI(4,5)P2 domains appear to undergo preferential exocytosis in stimulated cells. PI(4,5)P2 directly regulates vesicle exocytosis by recruiting and activating PI(4,5)P2-binding proteins that regulate SNARE protein function including CAPS, Munc13-1/2, synaptotagmin-1, and other C2 domain-containing proteins. These PI(4,5)P2 effector proteins are coincidence detectors that engage in multiple interactions at vesicle exocytic sites. The SNARE protein syntaxin-1 also binds to PI(4,5)P2, which promotes clustering, but an activating role for PI(4,5)P2 in syntaxin-1 function remains to be fully characterized. Similar principles underlie polarized constitutive vesicle fusion mediated in part by the PI(4,5)P2-binding subunits of the exocyst complex (Sec3, Exo70). Overall, focal vesicle exocytosis occurs at sites landmarked by PI(4,5)P2, which serves to recruit and/or activate multifunctional PI(4,5)P2-binding proteins. PMID:25280637

Knife-assisted snare resection: a novel technique for resection of scarred polyps in the colon.

PubMed

Chedgy, Fergus J Q; Bhattacharyya, Rupam; Kandiah, Kesavan; Longcroft-Wheaton, Gaius; Bhandari, Pradeep

2016-03-01

There have been significant advances in the management of complex colorectal polyps. Previous failed resection or polyp recurrence is associated with significant fibrosis, making endoscopic resection extremely challenging; the traditional approach to these lesions is surgery. The aim of this study was to evaluate the efficacy of a novel, knife-assisted snare resection (KAR) technique in the resection of scarred colonic polyps. This was a prospective cohort study of patients, in whom the KAR technique was used to resect scarred colonic polyps > 2  cm in size. Patients had previously undergone endoscopic mucosal resection (EMR) and developed recurrence, or EMR had been attempted but was aborted as a result of technical difficulty. A total of 42 patients underwent KAR of large (median 40  mm) scarred polyps. Surgery for benign disease was avoided in 38 of 41 patients (93 %). No life-threatening complications occurred. Recurrence was seen in six patients (16 %), five of whom underwent further endoscopic resection. The overall cure rate for KAR in complex scarred colonic polyps was 90 %. KAR of scarred colonic polyps by an expert endoscopist was an effective and safe technique with low recurrence rates. © Georg Thieme Verlag KG Stuttgart · New York.

Music Preferences, Friendship, and Externalizing Behavior in Early Adolescence: A SIENA Examination of the Music Marker Theory Using the SNARE Study.

PubMed

Franken, Aart; Keijsers, Loes; Dijkstra, Jan Kornelis; Ter Bogt, Tom

2017-08-01

Music Marker Theory posits that music is relevant for the structuring of peer groups and that rock, urban, or dance music preferences relate to externalizing behavior. The present study tested these hypotheses, by investigating the role of music preference similarity in friendship selection and the development of externalizing behavior, while taking the effects of friends' externalizing behavior into account. Data were used from the first three waves of the SNARE (Social Network Analysis of Risk behavior in Early adolescence) study (N = 1144; 50% boys; M age  = 12.7; SD = 0.47), including students who entered the first-year of secondary school. Two hypotheses were tested. First, adolescents were expected to select friends based both on a similarity in externalizing behavior and music genre preference. Second, a preference for rock, urban, or dance, music types was expected to predict the development of externalizing behavior, even when taking friends' influence on externalizing behavior into account. Stochastic Actor-Based Modeling indicated that adolescents select their friends based on both externalizing behavior and highbrow music preference. Moreover, both friends' externalizing behavior and a preference for dance music predicted the development of externalizing behavior. Intervention programs might focus on adolescents with dance music preferences.

Immunocytochemical analysis of syntaxin-1 in rat circumvallate taste buds.

PubMed

Yang, Ruibiao; Ma, Huazhi; Thomas, Stacey M; Kinnamon, John C

2007-06-20

Mammalian buds contain a variety of morphological taste cell types, but the type III taste cell is the only cell type that has synapses onto nerve processes. We hypothesize that taste cell synapses utilize the SNARE protein machinery syntaxin, SNAP-25, and synaptobrevin, as is used by synapses in the central nervous system (CNS) for Ca2+-dependent exocytosis. Previous studies have shown that taste cells with synapses display SNAP-25- and synaptobrevin-2-like immunoreactivity (LIR) (Yang et al. [2000a] J Comp Neurol 424:205-215, [2004] J Comp Neurol 471:59-71). In the present study we investigated the presynaptic membrane protein, syntaxin-1, in circumvallate taste buds of the rat. Our results indicate that diffuse cytoplasmic and punctate syntaxin-1-LIR are present in different subsets of taste cells. Diffuse, cytoplasmic syntaxin-1-LIR is present in type III cells while punctate syntaxin-1-LIR is present in type II cells. The punctate syntaxin-1-LIR is believed to be associated with Golgi bodies. All of the synapses associated with syntaxin-1-LIR taste cells are from type III cells onto nerve processes. These results support the proposition that taste cell synapses use classical SNARE machinery such as syntaxin-1 for neurotransmitter release in rat circumvallate taste buds. (c) 2007 Wiley-Liss, Inc.

Synaptobrevin Transmembrane Domain Dimerization Studied by Multiscale Molecular Dynamics Simulations

PubMed Central

Han, Jing; Pluhackova, Kristyna; Wassenaar, Tsjerk A.; Böckmann, Rainer A.

2015-01-01

Synaptic vesicle fusion requires assembly of the SNARE complex composed of SNAP-25, syntaxin-1, and synaptobrevin-2 (sybII) proteins. The SNARE proteins found in vesicle membranes have previously been shown to dimerize via transmembrane (TM) domain interactions. While syntaxin homodimerization is supposed to promote the transition from hemifusion to complete fusion, the role of synaptobrevin’s TM domain association in the fusion process remains poorly understood. Here, we combined coarse-grained and atomistic simulations to model the homodimerization of the sybII transmembrane domain and of selected TM mutants. The wild-type helix is shown to form a stable, right-handed dimer with the most populated helix-helix interface, including key residues predicted in a previous mutagenesis study. In addition, two alternative binding interfaces were discovered, which are essential to explain the experimentally observed higher-order oligomerization of sybII. In contrast, only one dimerization interface was found for a fusion-inactive poly-Leu mutant. Moreover, the association kinetics found for this mutant is lower as compared to the wild-type. These differences in dimerization between the wild-type and the poly-Leu mutant are suggested to be responsible for the reported differences in fusogenic activity between these peptides. This study provides molecular insight into the role of TM sequence specificity for peptide aggregation in membranes. PMID:26287628

Spatiotemporal dynamics of membrane remodeling and fusion proteins during endocytic transport

PubMed Central

Arlt, Henning; Auffarth, Kathrin; Kurre, Rainer; Lisse, Dominik; Piehler, Jacob; Ungermann, Christian

2015-01-01

Organelles of the endolysosomal system undergo multiple fission and fusion events to combine sorting of selected proteins to the vacuole with endosomal recycling. This sorting requires a consecutive remodeling of the organelle surface in the course of endosomal maturation. Here we dissect the remodeling and fusion machinery on endosomes during the process of endocytosis. We traced selected GFP-tagged endosomal proteins relative to exogenously added fluorescently labeled α-factor on its way from the plasma membrane to the vacuole. Our data reveal that the machinery of endosomal fusion and ESCRT proteins has similar temporal localization on endosomes, whereas they precede the retromer cargo recognition complex. Neither deletion of retromer nor the fusion machinery with the vacuole affects this maturation process, although the kinetics seems to be delayed due to ESCRT deletion. Of importance, in strains lacking the active Rab7-like Ypt7 or the vacuolar SNARE fusion machinery, α-factor still proceeds to late endosomes with the same kinetics. This indicates that endosomal maturation is mainly controlled by the early endosomal fusion and remodeling machinery but not the downstream Rab Ypt7 or the SNARE machinery. Our data thus provide important further understanding of endosomal biogenesis in the context of cargo sorting. PMID:25657322

Rolling blackout is required for synaptic vesicle exocytosis.

PubMed

Huang, Fu-De; Woodruff, Elvin; Mohrmann, Ralf; Broadie, Kendal

2006-03-01

Rolling blackout (RBO) is a putative transmembrane lipase required for phospholipase C-dependent phosphatidylinositol 4,5-bisphosphate-diacylglycerol signaling in Drosophila neurons. Conditional temperature-sensitive (TS) rbo mutants display complete, reversible paralysis within minutes, demonstrating that RBO is acutely required for movement. RBO protein is localized predominantly in presynaptic boutons at neuromuscular junction (NMJ) synapses and throughout central synaptic neuropil, and rbo TS mutants display a complete, reversible block of both central and peripheral synaptic transmission within minutes. This phenotype appears limited to adults, because larval NMJs do not manifest the acute blockade. Electron microscopy of adult rbo TS mutant boutons reveals an increase in total synaptic vesicle (SV) content, with a concomitant shrinkage of presynaptic bouton size and an accumulation of docked SVs at presynaptic active zones within minutes. Genetic tests reveal a synergistic interaction between rbo and syntaxin1A TS mutants, suggesting that RBO is required in the mechanism of N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated SV exocytosis, or in a parallel pathway necessary for SV fusion. The rbo TS mutation does not detectably alter SNARE complex assembly, suggesting a downstream requirement in SV fusion. We conclude that RBO plays an essential role in neurotransmitter release, downstream of SV docking, likely mediating SV fusion.

The Fas/Fap-1/Cav-1 complex regulates IL-1RA secretion in mesenchymal stem cells to accelerate wound healing.

PubMed

Kou, Xiaoxing; Xu, Xingtian; Chen, Chider; Sanmillan, Maria Laura; Cai, Tao; Zhou, Yanheng; Giraudo, Claudio; Le, Anh; Shi, Songtao

2018-03-14

Mesenchymal stem cells (MSCs) are capable of secreting exosomes, extracellular vesicles, and cytokines to regulate cell and tissue homeostasis. However, it is unknown whether MSCs use a specific exocytotic fusion mechanism to secrete exosomes and cytokines. We show that Fas binds with Fas-associated phosphatase-1 (Fap-1) and caveolin-1 (Cav-1) to activate a common soluble N -ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE)-mediated membrane fusion mechanism to release small extracellular vesicles (sEVs) in MSCs. Moreover, we reveal that MSCs produce and secrete interleukin-1 receptor antagonist (IL-1RA) associated with sEVs to maintain rapid wound healing in the gingiva via the Fas/Fap-1/Cav-1 cascade. Tumor necrosis factor-α (TNF-α) serves as an activator to up-regulate Fas and Fap-1 expression via the nuclear factor κB pathway to promote IL-1RA release. This study identifies a previously unknown Fas/Fap-1/Cav-1 axis that regulates SNARE-mediated sEV and IL-1RA secretion in stem cells, which contributes to accelerated wound healing. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Transcatheter Closure of Patent Foramen Ovale in Patients with Platypnea-Orthodeoxia: Results of a Multicentric French Registry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerin, P.; Lambert, V.; Godart, F.

Background. Dyspnea and the decrease in arterial saturation in the upright position in elderly subjects is described as platypnea-orthodeoxia syndrome (POS). POS is secondary to the occurrence of an atrial right-to-left shunt through a patent foramen ovale (PFO). Methods. This French multicentric study reports on 78 patients (mean age 67 {+-} 11.3 years) with POS who had transcatheter closure of the PFO; frequently associated diseases were pneumonectomy (n = 36) and an ascending aortic aneurysm (n = 11). In all patients, the diagnosis was confirmed by transthoracic or/and transesophageal echocardiography. Five different closure devices were used: Amplatz (n = 45),more » Cardioseal (n = 13), Sideris (n = 11), Das Angel Wings (n = 8) and Starflex (n = 1). Closure was successful in 76 patients (97%). Results. Oxygen saturation increased immediately after occlusion from 84.6 {+-} 10.7% to 95.1 {+-} 6.4% (p < 0.001) and dyspnea improved from grade 2.7 {+-} 0.7 to grade 1 {+-} 1 (p < 0.001). A small residual shunt was immediately observed in 5 patients (3 with the Cardioseal device, 1 with the Sideris and 1 with the Amplatz) leading to the implantation of a second device in one case (Cardioseal). Two early deaths occurred unrelated to the procedure (one due to sepsis probably related to pneumonectomy, another due to respiratory insufficiency). Other complications were: a small shunt between the aorta and the left atrium, two atrial fibrillations and a left-sided thrombus which disappeared with anticoagulant therapy. At a mean follow-up of 15 {+-} 12 months, there were 7 late deaths related to the underlying disease. Conclusion. Percutaneous occlusion of the foramen ovale is safe and gives excellent results thanks to continuing improvement in available devices. This technique enables some patients in an unstable condition to avoid a surgical closure.« less

Optimizing logistics for balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices by doing away with the indwelling balloon: concept and techniques.

PubMed

Saad, Wael E; Nicholson, David B

2013-06-01

Since the conception of balloon-occluded retrograde transvenous obliteration (BRTO) of gastric varices 25 years ago, the placement of an indwelling balloon for hours has been central to the BRTO procedure. Numerous variables and variations of the BRTO procedure have been described, including methods to reduce sclerosant, combining percutaneous transhepatic obliteration, varying sclerosant, and using multiple sclerosants within the same procedure. However, the consistent feature of BRTO has always remained the indwelling balloon. Placing an indwelling balloon over hours for the BRTO procedure is a logistical burden that taxes the interventional radiology team and hospital resources. Substituting the balloon with hardware (coils or Amplatzer vascular plugs [AVPs] or both) is technically feasible and its risks most likely correlate with gastrorenal shunt (GRS) size. The current authors use packed 0.018- or 0.035-in coils or both for small gastric variceal systems (GRS size A and B) and AVPs for GRS sizes up to size E (from size A-E). The current authors recommend an indwelling balloon (no hardware substitute) for very large gastric variceal system (GRS size F). Substituting the indwelling balloon for hardware in size F and potentially size E GRS can also be risky. The current article describes the techniques of placing up to 16-mm AVPs through balloon occlusion guide catheters and then deflating the balloon once it has been substituted with the AVPs. In addition, 22-mm AVPs can be placed through sheaths once the balloon occlusion catheters are removed to further augment the 16-mm Amplatzer occlusion. To date, there are no studies describing, let alone evaluating, the clinical feasibility of performing BRTO without indwelling balloons. The described techniques have been successfully performed by the current authors. However, the long-term safety and effectiveness of these techniques is yet to be determined. Copyright © 2013 Elsevier Inc. All rights reserved.

Cardi-O-Fix duct occluder versus Amplatzer duct occluder for closure of patent ductus arteriosus.

PubMed

Celebi, Ahmet; Demir, Ibrahim Halil; Saritaş, Türkay; Dedeoğlu, Reyhan; Yucel, Ilker Kemal; Demir, Fadli; Erdem, Abdullah

2013-11-15

We sought to investigate the safety, efficacy, and follow-up results of percutaneous patent ductus arteriosus (PDA) closure using the novel Cardi-O-Fix duct occluder (CDO), a device similar to but less expensive than the Amplatzer duct occluder (ADO). We also aimed to compare these two devices in terms of results. Between March 2005 and May 2012, 167 patients diagnosed with moderate-to-large PDA underwent transcatheter closure. ADO was used in 56 (33.5%) patients with a mean age of 8.1 ± 11.9 years (3.6 months-56 years), whereas CDO was used in 111 (66.5%) patients with a mean age of 12.6 ± 14.6 years (4.8 months-63 years). The narrowest PDA diameter, the used device diameter, procedure time, fluoroscopy time, and residual shunt rates were similar between the two groups. Procedural success rate was 100% in both groups. Although the residual shunt rate was higher in the CDO group immediately after the procedure, the difference was not statistically significant (12.6 vs. 8.9%; P = 0.3). There was no statistically significant difference between groups at discharge and during follow-up. No deaths occurred in any of the groups, and there were no differences in complication rates during the short- and mid-term follow-up periods (CDO 7/111 vs. ADO 5/56; P = 0.5 π). The CDO can be used for PDA closure because of its safety, effectiveness, and simplicity in use. It is available in bigger sizes and can be used in patients with large defects. According to our short- and mid-term findings, the results it yields are similar to those of the ADO; thus, it may be the preferred choice owing to its low cost and large size variability. Copyright © 2013 Wiley Periodicals, Inc.

Percutaneous closure of patent ductus arteriosus in children using amplatzer duct occluder II: relationship between PDA type and risk of device protrusion into the descending aorta.

PubMed

Masri, Samer; El Rassi, Issam; Arabi, Mariam; Tabbakh, Anas; Bitar, Fadi

2015-08-01

To compare the efficacy and safety of Amplatzer Duct Occluder II (ADOII) among the various patent ductus arteriosus (PDA) types, and to assess the association between development of aortic obstruction and the PDA type in terms of measurable parameters as the device angulation and distance of upper end protrusion into the aortic lumen. Retrospective cohort study involving 50 consecutive subjects who underwent ADO II device closure of PDA. The median age and weight at intervention were 13 months (5.5 months to 18 years) and 11 (6-67) kg respectively. The median smallest ductal diameter by angiography was 3.2 (1.9-5.4) mm. Thirty two patients had type A PDA, 5 had type C, 5 had type D, and 8 had type E. Residual shunt was seen in only 1 patient who had a tubular PDA and resolved within 2 months of the procedure. No device embolization or pulmonary side protrusion were noted. There was a 16% aortic protrusion rate. The median distance of protrusion of the upper end of the device into the aortic lumen was 3.1 (0-9) mm and the median angle formed between the aortic end of the device and the PDA take-off was 10.4 (0-80.6) degrees. These latter parameters of aortic obstruction were significantly higher in the non-conical PDA group as compared to the conical PDA. Nevertheless, there was no significant coarctation due to aortic retention disc protrusion. Device closure of PDA using the ADO II is a safe procedure for chosen types of PDA. We demonstrated a novel technique for objective assessment of device protrusion into the descending aorta based on measurable parameters. ADOII device closure of non-conical PDAs warrants closer follow ups. © 2015 Wiley Periodicals, Inc.

A Retrospective Study of 1526 Cases of Transcatheter Occlusion of Patent Ductus Arteriosus

PubMed Central

Jin, Mei; Liang, Yong-Mei; Wang, Xiao-Fang; Guo, Bao-Jing; Zheng, Ke; Gu, Yan; Lyu, Zhen-Yu

2015-01-01

Background: Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases and began to get treated by transcatheter occlusion since 1997 in China. Since then, several devices have been invented for occluding PDA. This study aimed to evaluate the technical feasibility, safety, and efficacy of transcatheter occlusion of PDA with different devices. Methods: One thousand five hundred and twenty-six patients (537 boys, 989 girls) with PDA from January 1997 to September 2014 underwent descending aortogram and transcatheter occlusion procedure. We retrospectively analyzed data of these patients, including gender, age, weight, size and morphology of PDA, and devices used in transcatheter occlusion, outcomes, and postoperational complications. Results: Median age and median weight were 4.0 years (range: 0.3–52.0 years old) and 15.3 kg (range: 4.5–91.0 kg), respectively. Mean ductal diameter, aortic ductal diameter, ductal length, and pulmonary artery pressure were 3.50 ± 2.15 mm, 10.08 ± 2.46 mm, 7.49 ± 3.02 mm, and 30.21 ± 17.28 mmHg, respectively. Morphology of PDA assessed by descending aortogram was of type A in 1428 patients, type B in 6 patients, type C in 79 patients, type D in 4 patients, and type E in 9 patients according to the classification of Krichenko. Of all the 1526 patients, 1497 patients underwent transcatheter PDA closure, among which 1492 were successful. Devices used were Amplatzer duct occluder I (ADO I, 1280, 85.8%), Cook detachable coils (116, 7.8%), ADO II (ADO II, 68, 4.6%), muscular VSD occluder (12, 0.8%), and Amplatzer vascular plug (16, 1.0%). Conclusions: Excellent occlusion rates with low complication rates were achieved with all devices regardless of PDA types. With transcatheter occlusion technique and devices developing, more patients with PDA can be treated with transcatheter closure both safely and efficiently. PMID:26315073

Clinically apparent long-term electric disturbances in the acute and very long-term of patent foramen ovale device-based closure.

PubMed

Rigatelli, Gianluca; Zuin, Marco; Pedon, Luigi; Zecchel, Roberto; Dell'Avvocata, Fabio; Carrozza, Antonio; Zennaro, Marco; Pastore, Gianni; Zanon, Francesco

2017-03-01

Incidence of electrical disturbances in patients submitted to transcatheter patent foramen ovale (PFO) closure has not been fully clarified in a large population. The aim of the study is to assess the incidence of atrial fibrillation, supraventricular tachi-arrhythmias, and atrio-ventricular block in the acute and very long-term follow-up. We reviewed the medical and instrumental data of 1000 consecutive patients (mean age 47.3±17.1years) prospectively enrolled in two centers over a 13-year period (February 1999 to February 2012) for right-to-left (R-to-L) shunt ICE-aided catheter-based closure using different devices. Successful transcatheter PFO closure was achieved in 99.8% of the patients. Implanted devices were: Amplatzer PFO Occluder in 463 patients (46.3%), Amplatzer ASD Cribriform Occluder in 420 patients (42.0%), Premere Occlusion System in 95 patients (9.5%), and Biostar Occluder in 22 patients (2.2%). Postprocedural electrical complications occurred in 5.9% of patients. The only independent predictors of electrophysiological complications were female gender (OR 2.3, 0.5-5.1 [95% CI], p<0.001) and device disk >30mm (OR 5.0, 1.2-7.2 [95% CI], p<0.001). On a mean follow-up of 12 .3±0.6years (minimum 4- maximum 17years), electrical complications occurred in 1.4% of patients including one only case of complete AVB and 5 cases of permanent AF. The only independent predictors were female gender (OR 2.3, 0.5-5.1 [95% CI], p<0.001) and device disk >30mm (OR 5.0, 1.2-7.2 [95% CI], p<0.001). Device-based closure of PFO using different devices, appeared very safe from an electrophysiological point of view with low incidence of electrical disturbances even in the very long-term follow-up. Copyright © 2016 Elsevier Inc. All rights reserved.

A Retrospective Study of 1,526 Cases of Transcatheter Occlusion of Patent Ductus Arteriosus.

PubMed

Jin, Mei; Liang, Yong-Mei; Wang, Xiao-Fang; Guo, Bao-Jing; Zheng, Ke; Gu, Yan; Lyu, Zhen-Yu

2015-09-05

Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases and began to get treated by transcatheter occlusion since 1997 in China. Since then, several devices have been invented for occluding PDA. This study aimed to evaluate the technical feasibility, safety, and efficacy of transcatheter occlusion of PDA with different devices. One thousand five hundred and twenty-six patients (537 boys, 989 girls) with PDA from January 1997 to September 2014 underwent descending aortogram and transcatheter occlusion procedure. We retrospectively analyzed data of these patients, including gender, age, weight, size and morphology of PDA, and devices used in transcatheter occlusion, outcomes, and postoperational complications. Median age and median weight were 4.0 years (range: 0.3-52.0 years old) and 15.3 kg (range: 4.5-91.0 kg), respectively. Mean ductal diameter, aortic ductal diameter, ductal length, and pulmonary artery pressure were 3.50 ± 2.15 mm, 10.08 ± 2.46 mm, 7.49 ± 3.02 mm, and 30.21 ± 17.28 mmHg, respectively. Morphology of PDA assessed by descending aortogram was of type A in 1428 patients, type B in 6 patients, type C in 79 patients, type D in 4 patients, and type E in 9 patients according to the classification of Krichenko. Of all the 1526 patients, 1497 patients underwent transcatheter PDA closure, among which 1492 were successful. Devices used were Amplatzer duct occluder I (ADO I, 1280, 85.8%), Cook detachable coils (116, 7.8%), ADO II (ADO II, 68, 4.6%), muscular VSD occluder (12, 0.8%), and Amplatzer vascular plug (16, 1.0%). Excellent occlusion rates with low complication rates were achieved with all devices regardless of PDA types. With transcatheter occlusion technique and devices developing, more patients with PDA can be treated with transcatheter closure both safely and efficiently.

Implementing Strategy in a Budget: A Model for the Coast Guard Reserve

DTIC Science & Technology

1990-06-01

Handbook, McGraw-Hill Book Co., 1983. Andrews, K. R., The Concept of Corporate Strategy, McGraw- Hill Book Co., 1965. Ansoff , H. Igor , Strategic...SNARE OKKARIIL. ADOPTION Of NEW MARKETIG CONCEPTS I CRATNE INCNRtImG MARKITIMCNGGNUP!S Figure 4.( Ansoff ,1979,p. 65) 17 The niche question focuses...domain. Ansoff observed the increasing competition for resources and commented: The explosive growth of expenditures for government and social welfare

Cor triatriatum dexter and atrial septal defect in a 43-year-old woman.

PubMed

Vukovic, Petar M; Kosevic, Dragana; Milicic, Miroslav; Jovovic, Ljiljana; Stojanovic, Ivan; Micovic, Slobodan

2014-08-01

Cor triatriatum dexter is a rare congenital heart anomaly in which a membrane divides the right atrium into 2 chambers. We report the case of a 43-year-old woman who had cor triatriatum dexter and a large atrial septal defect. During attempted percutaneous closure, the balloon disrupted the membrane and revealed that the defect had no inferior rim, precluding secure placement of an Amplatzer Septal Occluder. Surgical treatment subsequently proved to be successful. In patients with an incomplete membrane and a septal defect with well-defined rims, percutaneous treatment can be the first choice. In patients who have cor triatriatum dexter and unfavorable anatomic features or concomitant complex heart anomalies, open-heart surgery remains the gold standard for treatment.

Cor Triatriatum Dexter and Atrial Septal Defect in a 43-Year-Old Woman

PubMed Central

Kosevic, Dragana; Milicic, Miroslav; Jovovic, Ljiljana; Stojanovic, Ivan; Micovic, Slobodan

2014-01-01

Cor triatriatum dexter is a rare congenital heart anomaly in which a membrane divides the right atrium into 2 chambers. We report the case of a 43-year-old woman who had cor triatriatum dexter and a large atrial septal defect. During attempted percutaneous closure, the balloon disrupted the membrane and revealed that the defect had no inferior rim, precluding secure placement of an Amplatzer Septal Occluder. Surgical treatment subsequently proved to be successful. In patients with an incomplete membrane and a septal defect with well-defined rims, percutaneous treatment can be the first choice. In patients who have cor triatriatum dexter and unfavorable anatomic features or concomitant complex heart anomalies, open-heart surgery remains the gold standard for treatment. PMID:25120397

Endovascular Treatment of an Aneurysmal Aberrant Systemic Artery Supplying a Pulmonary Sequestrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristensen, Katrine Lawaetz, E-mail: klk@dadlnet.dk; Duus, Louise Aarup, E-mail: louise.brodersen@gmail.com; Elle, Bo, E-mail: Bo.Elle@rsyd.dk

An aberrant systemic artery originating from the abdominal aorta supplying a pulmonary sequestration is a rare congenital malformation. This causes a left-to-left shunt. Symptoms include recurrent pneumonias, hemoptysis, and, in the long term, heart failure. Aneurysm of the aberrant vessel is rarely seen. Traditionally, treatment of pulmonary sequestrations includes ligation of the feeding vessel and lobectomy. A new promising treatment is an endovascular approach. Only a few cases describe endovascular treatment of pulmonary sequestration. This is the first published case of a giant aneurysmal branch from the abdominal aorta to the normal basal segments of the lung, successfully occluded withmore » an Amplatzer Vascular Plug II (AVP II, St.Jude Medical, MN, USA) alone.« less

Congenital extrahepatic portosystemic shunt (Abernethy malformation) treated endovascularly with vascular plug shunt closure.

PubMed

Passalacqua, Matthew; Lie, Kevin T; Yarmohammadi, Hooman

2012-01-01

A 3-year-old boy, who presented with progressive cyanosis and hypoxia, was diagnosed with a large congenital extrahepatic portosystemic shunt, interrupted IVC with azygos continuation, and multiple congenital anomalies. Traditionally open and laparoscopic surgical techniques have been used to treat this malformation. Endovascular repair using a 16-mm Amplatzer vascular plug (AGA Medical Corporation, Golden Valley, Minnesota, USA) was used to occlude the shunt. Immediate post-placement venography demonstrated cessation of flow within the shunt and increased portal venous flow. The patient's hypoxia and cyanosis decreased significantly, and he was discharged on the 5th post-procedure day in stable clinical condition. Three months follow-up evaluation demonstrated the vascular plug in place, unchanged in position.

Congenital Intrahepatic Portosystemic Venous Shunt and Liver Mass in a Child Patient: Successful Endovascular Treatment with an Amplatzer Vascular Plug (AVP)

PubMed Central

Lee, Sae Ah; Lee, Young Seok; Lee, Kun Song

2010-01-01

A congenital intrahepatic portosystemic shunt is a rare anomaly; but, the number of diagnosed cases has increased with advanced imaging tools. Symptomatic portosystemic shunts, especially those that include hyperammonemia, should be treated; and various endovascular treatment methods other than surgery have been reported. Hepatic masses with either an intra- or extrahepatic shunt also have been reported, and the mass is another reason for treatment. Authors report a case of a congenital intrahepatic portosystemic shunt with a hepatic mass that was successfully treated using a percutaneous endovascular approach with vascular plugs. By the time the first short-term follow-up was conducted, the hepatic mass had disappeared. PMID:20808706

Left ventricular systolic dysfunction after transcatheter closure of a large patent ductus arteriosus.

PubMed

Galal, Mohammed Omar; Arfi, Muhammed Amin; Nicole, Sekarski; Payot, Maurice; Hussain, Arif; Qureshi, Shakeel

2005-11-01

A 12-year-old boy reported in outpatient department with history of shortness of breath and dyspnoea on moderate exertion. Physical examination was significant for bounding pulses and for a continuous murmur III/VI, best heard at the left upper sternal border. Echocardiography confirmed a large patent arterial duct with shortening fraction of 33%. He underwent successful transcatheter closure of the patent arterial, using Amplatzer duct occluder 12/10. Few hours later echocardiography revealed an unexpected, yet important depression of left ventricular systolic function with shortening fraction decreasing to 24% and then two weeks later decreasing further to 20%. At a follow-up after four months, he had improved clinically but left ventricular dysfunction still persisted with shortening fraction of 24%.

Escaping the snare of chronological growth and launching a free curve alternative: General deviance as latent growth model

PubMed Central

WOOD, PHILLIP KARL; JACKSON, KRISTINA M.

2014-01-01

Researchers studying longitudinal relationships among multiple problem behaviors sometimes characterize autoregressive relationships across constructs as indicating “protective” or “launch” factors or as “developmental snares.” These terms are used to indicate that initial or intermediary states of one problem behavior subsequently inhibit or promote some other problem behavior. Such models are contrasted with models of “general deviance” over time in which all problem behaviors are viewed as indicators of a common linear trajectory. When fit of the “general deviance” model is poor and fit of one or more autoregressive models is good, this is taken as support for the inhibitory or enhancing effect of one construct on another. In this paper, we argue that researchers consider competing models of growth before comparing deviance and time-bound models. Specifically, we propose use of the free curve slope intercept (FCSI) growth model (Meredith & Tisak, 1990) as a general model to typify change in a construct over time. The FCSI model includes, as nested special cases, several statistical models often used for prospective data, such as linear slope intercept models, repeated measures multivariate analysis of variance, various one-factor models, and hierarchical linear models. When considering models involving multiple constructs, we argue the construct of “general deviance” can be expressed as a single-trait multimethod model, permitting a characterization of the deviance construct over time without requiring restrictive assumptions about the form of growth over time. As an example, prospective assessments of problem behaviors from the Dunedin Multidisciplinary Health and Development Study (Silva & Stanton, 1996) are considered and contrasted with earlier analyses of Hussong, Curran, Moffitt, and Caspi (2008), which supported launch and snare hypotheses. For antisocial behavior, the FCSI model fit better than other models, including the linear chronometric growth curve model used by Hussong et al. For models including multiple constructs, a general deviance model involving a single trait and multimethod factors (or a corresponding hierarchical factor model) fit the data better than either the “snares” alternatives or the general deviance model previously considered by Hussong et al. Taken together, the analyses support the view that linkages and turning points cannot be contrasted with general deviance models absent additional experimental intervention or control. PMID:23880389

Qa-SNAREs localized to the trans-Golgi network regulate multiple transport pathways and extracellular disease resistance in plants

PubMed Central

Uemura, Tomohiro; Kim, Hyeran; Saito, Chieko; Ebine, Kazuo; Ueda, Takashi; Schulze-Lefert, Paul; Nakano, Akihiko

2012-01-01

In all eukaryotic cells, a membrane-trafficking system connects the post-Golgi organelles, such as the trans-Golgi network (TGN), endosomes, vacuoles, and the plasma membrane. This complex network plays critical roles in several higher-order functions in multicellular organisms. The TGN, one of the important organelles for protein transport in the post-Golgi network, functions as a sorting station, where cargo proteins are directed to the appropriate post-Golgi compartments. Unlike its roles in animal and yeast cells, the TGN has also been reported to function like early endosomal compartments in plant cells. However, the physiological roles of the TGN functions in plants are not understood. Here, we report a study of the SYP4 group (SYP41, SYP42, and SYP43), which represents the plant orthologs of the Tlg2/syntaxin16 Qa-SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) that localizes on the TGN in yeast and animal cells. The SYP4 group regulates the secretory and vacuolar transport pathways in the post-Golgi network and maintains the morphology of the Golgi apparatus and TGN. Consistent with a secretory role, SYP4 proteins are required for extracellular resistance responses to a fungal pathogen. We also reveal a plant cell-specific higher-order role of the SYP4 group in the protection of chloroplasts from salicylic acid-dependent biotic stress. PMID:22307646

Early Adolescent Friendship Selection Based on Externalizing Behavior: the Moderating Role of Pubertal Development. The SNARE Study.

PubMed

Franken, Aart; Prinstein, Mitchell J; Dijkstra, Jan Kornelis; Steglich, Christian E G; Harakeh, Zeena; Vollebergh, Wilma A M

2016-11-01

This study examined friendship (de-)selection processes in early adolescence. Pubertal development was examined as a potential moderator. It was expected that pubertal development would be associated with an increased tendency for adolescents to select their friends based on their similarities in externalizing behavior engagement (i.e., delinquency, alcohol use, and tobacco use). Data were used from the first three waves of the SNARE (Social Network Analysis of Risk behavior in Early adolescence) study (N = 1144; 50 % boys; M age  = 12.7; SD = 0.47), including students who entered the first year of secondary school. The hypothesis was tested using Stochastic Actor-Based Modeling in SIENA. While taking the network structure into account, and controlling for peer influence effects, the results supported this hypothesis. Early adolescents with higher pubertal development were as likely as their peers to select friends based on similarity in externalizing behavior and especially likely to remain friends with peers who had a similar level of externalizing behavior, and thus break friendship ties with dissimilar friends in this respect. As early adolescents are actively engaged in reorganizing their social context, adolescents with a higher pubertal development are especially likely to lose friendships with peers who do not engage in externalizing behavior, thus losing an important source of adaptive social control (i.e., friends who do not engage in externalizing behavior).

Assessing the Potential Threat Landscape of a Proposed Reintroduction Site for Carnivores

PubMed Central

Page, Samantha K.; Parker, Daniel M.; Peinke, Dean M.; Davies-Mostert, Harriet T.

2015-01-01

This study provides a framework to assess the feasibility of reintroducing carnivores into an area, using African wild dogs (Lycaon pictus) as an example. The Great Fish River Nature Reserve in the Eastern Cape Province, South Africa, has been identified as a potential reserve to reintroduce wild dogs, and we applied this framework to provide a threat assessment of the surrounding area to determine potential levels of human-wildlife conflict. Although 56% of neighbouring landowners and local communities were positive about a wild dog reintroduction, data collected from questionnaire surveys revealed that human-wild dog conflict is a potential threat to wild dog survival in the area. Additional potential threats include diseases, snaring, poaching and hunting wild dogs for the use of traditional medicine. A threat index was developed to establish which properties harboured the greatest threats to wild dogs. This index was significantly influenced by the respondent’s first language (isiXhosa had more positive indices), education level (poorer education was synonymous with more positive threat indices), land use (wildlife ranching being the most negative) and land tenure (community respondents had more positive indices than private landowners). Although threats are present, they can be effectively mitigated through strategies such as carnivore education programs, vaccination campaigns and anti-snare patrols to promote a successful reintroduction of this endangered canid. PMID:25822468

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kos, Sebastian, E-mail: skos@gmx.de; Guerke, Lorenz; Jacob, Augustinus L.

Purpose: This study was designed to demonstrate the applicability of a combined needle-based re-entry catheter and 'cheese-wire' technique for fenestration of abdominal aortic dissection membranes. Methods: Four male patients (mean age: 65 years) with acute complicated aortic type B dissections were treated at our institution by fenestrating the abdominal aortic dissection membrane using a hybrid technique. This technique combined an initial membrane puncture with a needle-based re-entry catheter using a transfemoral approach. A guidewire was passed through the re-entry catheter and across the membrane. Using a contralateral transfemoral access, this guidewire was then snared, creating a through-and-through wire access. Themore » membrane was then fenestrated using the cheese-wire maneuver. Results: We successfully performed: (a) membrane puncture; (b) guidewire passage; (c) guidewire snaring; and (d) cheese-wire maneuver in all four cases. After this maneuver, decompression of the false lumen and acceptable arterial inflow into the true lumen was observed in all cases. The dependent visceral arteries were reperfused. In one case, portions of the fenestrated membrane occluded the common iliac artery, which was immediately and successfully stented. In another case, long-standing intestinal hypoperfusion before the fenestration resulted in reperfusion-related shock and intraoperative death of the patient. Conclusions: The described hybrid approach for fenestration of dissection membranes is technically feasible and may be established as a therapeutic method in cases with a complicated type B dissection.« less

Efficacy of Precut Endoscopic Mucosal Resection for Treatment of Rectal Neuroendocrine Tumors

PubMed Central

So, Hoonsub; Yoo, Su Hyun; Han, Seungbong; Kim, Gwang-un; Seo, Myeongsook; Hwang, Sung Wook; Yang, Dong-Hoon; Byeon, Jeong-Sik

2017-01-01

Background/Aims Endoscopic resection is the first-line treatment for rectal neuroendocrine tumors (NETs) measuring <1 cm and those between 1 and 2 cm in size. However, conventional endoscopic resection cannot achieve complete resection in all cases. We aimed to analyze clinical outcomes of precut endoscopic mucosal resection (EMR-P) used for the management of rectal NET. Methods EMR-P was used to treat rectal NET in 72 patients at a single tertiary center between 2011 and 2015. Both, circumferential precutting and EMR were performed with the same snare device in all patients. Demographics, procedural details, and histopathological features were reviewed for all cases. Results Mean size of the tumor measured endoscopically was 6.8±2.8 mm. En bloc and complete resection was achieved in 71 (98.6%) and 67 patients (93.1%), respectively. The mean time required for resection was 9.0±5.6 min. Immediate and delayed bleeding developed in six (8.3%) and 4 patients (5.6%), respectively. Immediate bleeding observed during EMR-P was associated with the risk of delayed bleeding. Conclusions Both, the en bloc and complete resection rates of EMR-P in the treatment of rectal NETs using the same snare for precutting and EMR were noted to be high. The procedure was short and safe. EMR-P may be a good treatment choice for the management of rectal NETs. PMID:29020763

Discrete, continuous, and stochastic models of protein sorting in the Golgi apparatus

PubMed Central

Gong, Haijun; Guo, Yusong; Linstedt, Adam

2017-01-01

The Golgi apparatus plays a central role in processing and sorting proteins and lipids in eukaryotic cells. Golgi compartments constantly exchange material with each other and with other cellular components, allowing them to maintain and reform distinct identities despite dramatic changes in structure and size during cell division, development, and osmotic stress. We have developed three minimal models of membrane and protein exchange in the Golgi—a discrete, stochastic model, a continuous ordinary differential equation model, and a continuous stochastic differential equation model—each based on two fundamental mechanisms: vesicle-coat-mediated selective concentration of cargoes and soluble N-ethylmaleimide-sensitive factor attachment protein receptor SNARE proteins during vesicle formation and SNARE-mediated selective fusion of vesicles. By exploring where the models differ, we hope to discover whether the discrete, stochastic nature of vesicle-mediated transport is likely to have appreciable functional consequences for the Golgi. All three models show similar ability to restore and maintain distinct identities over broad parameter ranges. They diverge, however, in conditions corresponding to collapse and reassembly of the Golgi. The results suggest that a continuum model provides a good description of Golgi maintenance but that considering the discrete nature of vesicle-based traffic is important to understanding assembly and disassembly of the Golgi. Experimental analysis validates a prediction of the models that altering guanine nucleotide exchange factor expression levels will modulate Golgi size. PMID:20365406

Local protein dynamics during microvesicle exocytosis in neuroendocrine cells.

PubMed

Somasundaram, Agila; Taraska, Justin

2018-06-06

Calcium triggered exocytosis is key to many physiological processes, including neurotransmitter and hormone release by neurons and endocrine cells. Dozens of proteins regulate exocytosis, yet the temporal and spatial dynamics of these factors during vesicle fusion remain unclear. Here we use total internal reflection fluorescence microscopy to visualize local protein dynamics at single sites of exocytosis of small synaptic-like microvesicles in live cultured neuroendocrine PC12 cells. We employ two-color imaging to simultaneously observe membrane fusion (using vesicular acetylcholine transporter (VAChT) tagged to pHluorin) and the dynamics of associated proteins at the moments surrounding exocytosis. Our experiments show that many proteins, including the SNAREs syntaxin1 and VAMP2, the SNARE modulator tomosyn, and Rab proteins, are pre-clustered at fusion sites and rapidly lost at fusion. The ATPase NSF is locally recruited at fusion. Interestingly, the endocytic BAR domain-containing proteins amphiphysin1, syndapin2, and endophilins are dynamically recruited to fusion sites, and slow the loss of vesicle membrane-bound cargo from fusion sites. A similar effect on vesicle membrane protein dynamics was seen with the over-expression of the GTPases dynamin1 and dynamin2. These results suggest that proteins involved in classical clathrin-mediated endocytosis can regulate exocytosis of synaptic-like microvesicles. Our findings provide insights into the dynamics, assembly, and mechanistic roles of many key factors of exocytosis and endocytosis at single sites of microvesicle fusion in live cells.

Multiband mucosectomy for advanced dysplastic lesions in the upper digestive tract

PubMed Central

Espinel, Jesús; Pinedo, Eugenia; Ojeda, Vanesa; del Rio, Maria Guerra

2015-01-01

Endoscopic resection (ER) is at present an accepted treatment for superficial gastrointestinal neoplasia. ER provides similar efficacy to surgery; however, it is minimally invasive and less expensive. Endoscopic mucosal resection (EMR) is superior to biopsy for diagnosing advanced dysplasia and can change the diagnostic grade and the management. Several EMR techniques have been described that are alternatively used dependent upon the endoscopist personal experience, the anatomic conditions and the endoscopic appearance of the lesion to be resected. The literature suggests that EMR offers comparable outcomes to surgery for selected indications. EMR techniques using a cap fitted endoscope and EMR using a ligation device [multiband mucosectomy (MBM)] are the most frequently use. MBM technique does not require submucosal injection as with the endoscopic resection-cap technique, multiple resections can be performed with the same snare, pre-looping the endoscopic resection-snare in the ridge of the cap is not necessary, MBM does not require withdrawal of the endoscope between resections and up to six consecutive resections can be performed. This reduces the time and cost required for the procedure, while also reducing patient discomfort. Despite the increasing popularity of MBM, data on the safety and efficacy of this technique in upper gastrointestinal lesions with advanced dysplasia, defined as those lesions that have high-grade dysplasia or early cancer, is limited. PMID:25901216

Adolescents’ thoughts about abstinence curb the return of marijuana use during and after treatment

PubMed Central

King, Kevin M.; Chung, Tammy; Maisto, Stephen A.

2009-01-01

Despite some evidence showing that readiness to change substance use predicts reductions in substance use among treated adolescents, there is little research on month-to-month changes in adolescents’ thoughts about abstinence and marijuana use during and after substance use treatment. The current study provides a test of the “snares” hypothesis, which posits that time-varying changes in adolescents’ motivation to abstain and perceived difficulty to abstain from marijuana use hinder, or snare, the return of regular marijuana use during and after treatment. Monthly data on thoughts about abstinence, marijuana use, and treatment utilization were collected over 6-month follow-up from 142 adolescents recruited from intensive outpatient treatment for substance use. Results provided some support for the snares hypothesis in that higher motivation to abstain (but not perceived difficulty) predicted fewer days of marijuana use, over and above both the adolescent’s average trajectory of marijuana use, the initial severity of their marijuana involvement, and the effects of treatment utilization. Moreover, this association was bi-directional, such that past-month marijuana use influenced both motivation to abstain and perceived difficulty to abstain. Study findings highlight the importance of abstinence-related cognitions as a key target of intervention during and after addictions treatment, and underscore the importance of considering recovery from substance use disorders as a dynamic process of change over time. PMID:19485595

UNC-18 Promotes Both the Anterograde Trafficking and Synaptic Function of Syntaxin

PubMed Central

McEwen, Jason M.

2008-01-01

The SM protein UNC-18 has been proposed to regulate several aspects of secretion, including synaptic vesicle docking, priming, and fusion. Here, we show that UNC-18 has a chaperone function in neurons, promoting anterograde transport of the plasma membrane soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein Syntaxin-1. In unc-18 mutants, UNC-64 (Caenorhabditis elegans Syntaxin-1) accumulates in neuronal cell bodies. Colocalization studies and analysis of carbohydrate modifications both suggest that this accumulation occurs in the endoplasmic reticulum. This trafficking defect is specific for UNC-64 Syntaxin-1, because 14 other SNARE proteins and two active zone markers were unaffected. UNC-18 binds to Syntaxin through at least two mechanisms: binding to closed Syntaxin, or to the N terminus of Syntaxin. It is unclear which of these binding modes mediates UNC-18 function in neurons. The chaperone function of UNC-18 was eliminated in double mutants predicted to disrupt both modes of Syntaxin binding, but it was unaffected in single mutants. By contrast, mutations predicted to disrupt UNC-18 binding to the N terminus of Syntaxin caused significant defects in locomotion behavior and responsiveness to cholinesterase inhibitors. Collectively, these results demonstrate the UNC-18 acts as a molecular chaperone for Syntaxin transport in neurons and that the two modes of UNC-18 binding to Syntaxin are involved in different aspects of UNC-18 function. PMID:18596236

Kutenai Indian Subsistence and Settlement Patterns.

DTIC Science & Technology

1984-09-01

acquisition of horses, they "were all but destroyed by small pox ," their remnants finally joining other Upper Kutenai bands. Apart from this statement’s...snare data obviously point strongly to the taking. - of land birds of the grouse, prairie chicken , quail type as well as fool hens. As commented upon...34 ° "". ... . . . . . . . . . . . . . . . . . . . . .. . ° 2 ° o ". °. ° " .- . 287 Hodge, Frederick Webb 1910 Handbook of American Indians North of Mexico . Bureau of "..r. American Ethnology

"Bail out" procedures for malpositioning of aortic valve prosthesis (CoreValve).

PubMed

Vavouranakis, Manolis; Vrachatis, Dimitrios A; Toutouzas, Konstantinos P; Chrysohoou, Christina; Stefanadis, Christodoulos

2010-11-05

Two techniques for correcting malpositioning occurring during percutaneous aortic valve replacement (PAVR) with the CoreValve ReValving™ System are described in this article. The "Removing and Reinserting Technique" was used in 2 patients, in whom the prosthesis was positioned too high. The "Snare Technique" was used in 1 patient, in whom the prosthesis was implanted too low. In all patients the aortic valve prosthesis was successfully re-implanted. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

SNAP-25 IN NEUROPSYCHIATRIC DISORDERS

PubMed Central

Corradini, Irene; Verderio, Claudia; Sala, Mariaelvina; Wilson, Michael C.; Matteoli, Michela

2009-01-01

SNAP-25 is plasma membrane protein which, together with syntaxin and the synaptic vesicle protein VAMP/synaptobrevin, forms the SNARE docking complex for regulated exocytosis. SNAP-25 also modulates different voltage-gated calcium channels, representing therefore a multifunctional protein that plays essential roles in neurotransmitter release at different steps. Recent genetic studies of human populations and of some mouse models implicate that alterations in SNAP-25 gene structure, expression and/or function may contribute directly to these distinct neuropsychiatric and neurological disorders. PMID:19161380

Transnasal Endoscope Locked in a Bent Position Causing Difficult Withdrawal

PubMed Central

Kumada, Takashi; Hisanaga, Yasuhiro

2014-01-01

We report a rare but severe complication of routine transnasal esophagogastroduodenoscopy (EGD). The tip of a transnasal endoscope was locked in a bent position. Since the bent tip was unable to be returned to a neutral position, the snare from another endoscope inserted transorally was used to straighten it, which allowed the transnasal endoscope to be withdrawn with only mild injury to the gastric mucosa. Endoscopists should be aware of this complication and how to manage it. PMID:26157831

Tulip deformity with Cera atrial septal defect devices: a report of 3 cases.

PubMed

Kohli, Vikas

2015-02-01

Device closure of secundum atrial septal defect (ASD) is the treatment of choice when anatomy is favourable. Amplatzer device has remained the gold standard for closure of ASD. Cobra deformity is a well-reported problem with devices. Recently, Tulip deformity has been reported in a single case. We report a series of cases where we noted Tulip deformity along with inability to retract the device in the sheath in Cera Lifetech devices. This resulted in prolongation of procedure, excessive fluoroscopic exposure and additional interventional procedures not usually anticipated in ASD device closure. We believe that the problem is due to the stiffness of the device resulting in its inability to be retracted into the sheath. We also report a unique way of retrieving the device.

Transcatheter closure of left ventricle to right atrial communication using cera duct occluder.

PubMed

Ganesan, Gnanavelu; Paul, G Justin; Mahadevan, Vaikom S

Left ventricle-right atrial communication could be congenital (Gerbode defect) or acquired as a complication of surgery or infective endocarditis and leads to volume overloading of pulmonary circulation. Two types, direct and indirect types are known depending on the involvement of septal tricuspid leaflet. Transcatheter closure of this defect is feasible and appears an attractive alternative to surgical management. Various devices like Amplatzer duct occluder I, II, Muscular ventricular septal defect device etc. have been used to close this defect. We report two patients, a preteen boy with direct left ventricle-right atrial communication as post operative complication and an adult female with indirect communication who underwent transcatheter closure with Cera duct occluder (Lifetech Scientific (Shenzhen), China). Copyright © 2017. Published by Elsevier B.V.

Delayed Infective Endocarditis with Mycotic Aneurysm Rupture below the Mechanical Valved Conduit after the Bentall Procedure

PubMed Central

Chen, Mei-Ling; Chen, Michael Y.; Yin, Wei-Hsian; Wei, Jeng; Wang, Ji-Hung

2014-01-01

The Bentall procedure is the gold standard for treating aortic dissection complicated with valvular and ascending aorta disease. Recent results for this procedure have been excellent; nearly 100% of patients remain free of infective endocarditis in long-term follow-up. We report a case of delayed Streptococcus agalactiae infective endocarditis complicated by mycotic aneurysm in a man who had undergone the Bentall procedure with a mechanical valve conduit 15 years previously. The mycotic aneurysm was located in the remnant aortic root, below the mechanical valve conduit, and later ruptured into the right atrium. The patient was treated conservatively and survived the acute period. Later, the aortic root defect was repaired successfully by means of a hybrid technique using a Amplatzer duct occluder. PMID:27122809

Characterization of Phospholipids in Insulin Secretory Granules and Mitochondria in Pancreatic Beta Cells and Their Changes with Glucose Stimulation*

PubMed Central

MacDonald, Michael J.; Ade, Lacmbouh; Ntambi, James M.; Ansari, Israr-Ul H.; Stoker, Scott W.

2015-01-01

The lipid composition of insulin secretory granules (ISG) has never previously been thoroughly characterized. We characterized the phospholipid composition of ISG and mitochondria in pancreatic beta cells without and with glucose stimulation. The phospholipid/protein ratios of most phospholipids containing unsaturated fatty acids were higher in ISG than in whole cells and in mitochondria. The concentrations of negatively charged phospholipids, phosphatidylserine, and phosphatidylinositol in ISG were 5-fold higher than in the whole cell. In ISG phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin, fatty acids 12:0 and 14:0 were high, as were phosphatidylserine and phosphatidylinositol containing 18-carbon unsaturated FA. With glucose stimulation, the concentration of many ISG phosphatidylserines and phosphatidylinositols increased; unsaturated fatty acids in phosphatidylserine increased; and most phosphatidylethanolamines, phosphatidylcholines, sphingomyelins, and lysophosphatidylcholines were unchanged. Unsaturation and shorter fatty acid length in phospholipids facilitate curvature and fluidity of membranes, which favors fusion of membranes. Recent evidence suggests that negatively charged phospholipids, such as phosphatidylserine, act as coupling factors enhancing the interaction of positively charged regions in SNARE proteins in synaptic or secretory vesicle membrane lipid bilayers with positively charged regions in SNARE proteins in the plasma membrane lipid bilayer to facilitate docking of vesicles to the plasma membrane during exocytosis. The results indicate that ISG phospholipids are in a dynamic state and are consistent with the idea that changes in ISG phospholipids facilitate fusion of ISG with the plasma membrane-enhancing glucose-stimulated insulin exocytosis. PMID:25762724

Biosurfactant mannosyl-erythritol lipid inhibits secretion of inflammatory mediators from RBL-2H3 cells.

PubMed

Morita, Yosuke; Tadokoro, Satoshi; Sasai, Masao; Kitamoto, Dai; Hirashima, Naohide

2011-12-01

Biosurfactant mannosyl-erythritol lipids (MELs) are glycolipids produced by microbes that have various biological activities. It has been reported that MELs exhibit excellent surface-activity and also various bioactivities, such as induction of cell differentiation and apoptosis. However, little is known about their action related to drug discovery or drug seeds. We investigated the effects of MELs on the secretion of inflammatory mediators from mast cells that play a central role in allergic responses. Mast cells secrete three kinds of inflammatory mediators and we quantified these secreted mediators by photometer or ELISA. The action mechanisms of MELs were studied by Ca(2+)-sensitive fluorescence dye and Western blotting of phosphorylated proteins. MELs inhibited exocytotic release by antigen stimulation in a dose-dependent manner. We also found that MELs inhibited antigen-induced secretion of leukotriene C(4) and cytokine TNF-α (tumor necrosis factor-α). The inhibitory action of MELs on mediator secretion was mediated by inhibition of Ca(2+) increase, phosphorylation of MAP kinases and SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) that serve as a molecular machinery for exocytotic membrane fusion. MELs have anti-inflammatory action inhibiting the secretion of inflammatory mediators from mast cells. MELs affects two of major intracellular signaling pathways including Ca(2+) increase and MAP kinases. MELs also inhibited the phosphorylation of SNARE proteins that is crucial for not only exocytosis but also intracellular vesicular trafficking. 2011 Elsevier B.V. All rights reserved.

All the wrong places: an unusual case of foreign body ingestion and inhalation.

PubMed

Tammana, V S; Valluru, N; Sanderson, A

2012-09-01

Intentional ingestion of foreign bodies is common in psychiatric patients and prison inmates. Timing of endoscopy for ingested foreign bodies varies and depends on the type and location of the foreign body in the gastrointestinal tract. We present the case of a 26-year-old man who was brought from a correctional facility after confessing to have swallowed a few shower curtain hooks. Abdominal X-ray done in the emergency room revealed multiple foreign bodies in the stomach. An upper endoscopy was done in the emergency room with the use of an overtube. The first metal piece was caught by a snare and removed with the endoscope. All other foreign bodies which were present on the abdominal X-ray could not be visualized initially as there was retained food in the stomach. After multiple attempts, four other foreign bodies were found and each one was caught by the forceps and then the scope was removed with the forceps holding the foreign body. There was an additional foreign body in the right mainstem bronchus. The patient had coughed up the foreign body and swallowed it into the gastrointestinal tract. A computed tomography scan of chest and abdomen was done for evaluation, which showed the foreign body in the cecum. To our knowledge, this is the first case report of a patient intentionally transferring a foreign body from one organ system to another. Colonoscopy was done and the foreign body was removed rectally with a snare without any complications.

Structure Based Discovery of Pan Active Botulinum Neurotoxin Inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vieni, Casey; McGillick, Brian; Kumaran, Desigan

Clostridium botulinum neurotoxins (BoNTs) released by the bacterium Clostridium botulinum are the most potent toxins causing the fatal disease called botulism. There are seven distinct serotypes of BoNTs (A to G) released by various strains of botulinum. They all have high sequence homology and similar three-dimensional structure. The toxicity of BoNT follows a four-step process – binding, internalization, translocation, and cleavage of its target protein, one of the three components of the SNARE complex (Soluble N-ethylmaleimde-sensitive factor attachment protein receptor) required for membrane docking and neurotransmitter release. Cleavage of one of the three proteins causes blockage of neurotransmitter release leadingmore » to flaccid paralysis. Though anyone of the above four steps could be a target for developing antidotes for botulism, the catalytic domain is the most suitable target for post exposure treatment. Of the seven serotypes BoNT/A, B, E and probably F affect humans, with BoNT/A considered to be the most potent. Development of drugs for botulism is focused on serotype specific inhibitors, but a pan-active inhibitor acting on several serotypes is preferable since it is difficult to identify the serotype before the treatment, especially since there is at least a 36-hour window before botulism can be diagnosed. Using structure-based drug discovery, we have developed three heptapeptides based on the SNARE proteins which inhibit BoNT/A, B and E equally well. Probable reasons for pan-activity of these peptides are discussed.« less

Disrupted apical exocytosis of cargo vesicles causes enteropathy in FHL5 patients with Munc18-2 mutations.

PubMed

Vogel, Georg F; van Rijn, Jorik M; Krainer, Iris M; Janecke, Andreas R; Posovszky, Carsten; Cohen, Marta; Searle, Claire; Jantchou, Prevost; Escher, Johanna C; Patey, Natalie; Cutz, Ernest; Müller, Thomas; Middendorp, Sabine; Hess, Michael W; Huber, Lukas A

2017-07-20

Familial hemophagocytic lymphohistiocytosis 5 (FHL5) is an autosomal recessive disease caused by mutations in STXBP2, coding for Munc18-2, which is required for SNARE-mediated membrane fusion. FHL5 causes hematologic and gastrointestinal symptoms characterized by chronic enteropathy that is reminiscent of microvillus inclusion disease (MVID). However, the molecular pathophysiology of FHL5-associated diarrhea is poorly understood. Five FHL5 patients, including four previously unreported patients, were studied. Morphology of duodenal sections was analyzed by electron and fluorescence microscopy. Small intestinal enterocytes and organoid-derived monolayers displayed the subcellular characteristics of MVID. For the analyses of Munc18-2-dependent SNARE-protein interactions, a Munc18-2 CaCo2-KO model cell line was generated by applying CRISPR/Cas9 technology. Munc18-2 is required for Slp4a/Stx3 interaction in fusion of cargo vesicles with the apical plasma membrane. Cargo trafficking was investigated in patient biopsies, patient-derived organoids, and the genome-edited model cell line. Loss of Munc18-2 selectively disrupts trafficking of certain apical brush-border proteins (NHE3 and GLUT5), while transport of DPPIV remained unaffected. Here, we describe the molecular mechanism how the loss of function of Munc18-2 leads to cargo-selective mislocalization of brush-border components and a subapical accumulation of cargo vesicles, as it is known from the loss of polarity phenotype in MVID.

A novel fenestration technique for abdominal aortic dissection membranes using a combination of a needle re-entry catheter and the "cheese-wire" technique.

PubMed

Kos, Sebastian; Gürke, Lorenz; Jacob, Augustinus L

2011-12-01

This study was designed to demonstrate the applicability of a combined needle-based re-entry catheter and "cheese-wire" technique for fenestration of abdominal aortic dissection membranes. Four male patients (mean age: 65 years) with acute complicated aortic type B dissections were treated at our institution by fenestrating the abdominal aortic dissection membrane using a hybrid technique. This technique combined an initial membrane puncture with a needle-based re-entry catheter using a transfemoral approach. A guidewire was passed through the re-entry catheter and across the membrane. Using a contralateral transfemoral access, this guidewire was then snared, creating a through-and-through wire access. The membrane was then fenestrated using the cheese-wire maneuver. We successfully performed: (a) membrane puncture; (b) guidewire passage; (c) guidewire snaring; and (d) cheese-wire maneuver in all four cases. After this maneuver, decompression of the false lumen and acceptable arterial inflow into the true lumen was observed in all cases. The dependent visceral arteries were reperfused. In one case, portions of the fenestrated membrane occluded the common iliac artery, which was immediately and successfully stented. In another case, long-standing intestinal hypoperfusion before the fenestration resulted in reperfusion-related shock and intraoperative death of the patient. The described hybrid approach for fenestration of dissection membranes is technically feasible and may be established as a therapeutic method in cases with a complicated type B dissection.

Structure Based Discovery of Pan Active Botulinum Neurotoxin Inhibitors

DOE PAGES

Vieni, Casey; McGillick, Brian; Kumaran, Desigan; ...

2018-02-14

Clostridium botulinum neurotoxins (BoNTs) released by the bacterium Clostridium botulinum are the most potent toxins causing the fatal disease called botulism. There are seven distinct serotypes of BoNTs (A to G) released by various strains of botulinum. They all have high sequence homology and similar three-dimensional structure. The toxicity of BoNT follows a four-step process – binding, internalization, translocation, and cleavage of its target protein, one of the three components of the SNARE complex (Soluble N-ethylmaleimde-sensitive factor attachment protein receptor) required for membrane docking and neurotransmitter release. Cleavage of one of the three proteins causes blockage of neurotransmitter release leadingmore » to flaccid paralysis. Though anyone of the above four steps could be a target for developing antidotes for botulism, the catalytic domain is the most suitable target for post exposure treatment. Of the seven serotypes BoNT/A, B, E and probably F affect humans, with BoNT/A considered to be the most potent. Development of drugs for botulism is focused on serotype specific inhibitors, but a pan-active inhibitor acting on several serotypes is preferable since it is difficult to identify the serotype before the treatment, especially since there is at least a 36-hour window before botulism can be diagnosed. Using structure-based drug discovery, we have developed three heptapeptides based on the SNARE proteins which inhibit BoNT/A, B and E equally well. Probable reasons for pan-activity of these peptides are discussed.« less

Coordination of golgin tethering and SNARE assembly: GM130 binds syntaxin 5 in a p115-regulated manner.

PubMed

Diao, Aipo; Frost, Laura; Morohashi, Yuichi; Lowe, Martin

2008-03-14

During membrane traffic, transport carriers are first tethered to the target membrane prior to undergoing fusion. Mechanisms exist to connect tethering with fusion, but in most cases, the details remain poorly understood. GM130 is a member of the golgin family of coiled-coil proteins tat is involved in membrane tethering at the endoplasmic reticulum (ER) to Golgi intermediate compartment and cis-Golgi. Here, we demonstrate that GM130 interacts with syntaxin 5, a t-SNARE also localized to the early secretory pathway. Binding to syntaxin 5 is specific, direct, and mediated by the membrane-proximal region of GM130. Interestingly, interaction with syntaxin 5 is inhibited by the binding of the vesicle docking protein p115 to a distal binding site in GM130. The interaction between GM130 and the small GTPase Rab1 is also inhibited by p115 binding. Our findings suggest a mechanism for coupling membrane tethering and fusion at the ER to Golgi intermediate compartment and cis-Golgi, with GM130 playing a central role in linking these processes. Consistent with this hypothesis, we find that depletion of GM130 by RNA interference slows the rate of ER to Golgi trafficking in vivo. The interactions of GM130 with syntaxin 5 and Rab1 are also regulated by mitotic phosphorylation, which is likely to contribute to the inhibition of ER to Golgi trafficking that occurs when mammalian cells enter mitosis.

Exosomes Derived from Mesenchymal Stromal Cells Promote Axonal Growth of Cortical Neurons.

PubMed

Zhang, Yi; Chopp, Michael; Liu, Xian Shuang; Katakowski, Mark; Wang, Xinli; Tian, Xinchu; Wu, David; Zhang, Zheng Gang

2017-05-01

Treatment of brain injury with exosomes derived from mesenchymal stromal cells (MSCs) enhances neurite growth. However, the direct effect of exosomes on axonal growth and molecular mechanisms underlying exosome-enhanced neurite growth are not known. Using primary cortical neurons cultured in a microfluidic device, we found that MSC-exosomes promoted axonal growth, whereas attenuation of argonaut 2 protein, one of the primary microRNA (miRNA) machinery proteins, in MSC-exosomes abolished their effect on axonal growth. Both neuronal cell bodies and axons internalized MSC-exosomes, which was blocked by botulinum neurotoxins (BoNTs) that cleave proteins of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. Moreover, tailored MSC-exosomes carrying elevated miR-17-92 cluster further enhanced axonal growth compared to native MSC-exosomes. Quantitative RT-PCR and Western blot analysis showed that the tailored MSC-exosomes increased levels of individual members of this cluster and activated the PTEN/mTOR signaling pathway in recipient neurons, respectively. Together, our data demonstrate that native MSC-exosomes promote axonal growth while the tailored MSC-exosomes can further boost this effect and that tailored exosomes can deliver their selective cargo miRNAs into and activate their target signals in recipient neurons. Neuronal internalization of MSC-exosomes is mediated by the SNARE complex. This study reveals molecular mechanisms that contribute to MSC-exosome-promoted axonal growth, which provides a potential therapeutic strategy to enhance axonal growth.

Endoscopic treatment by snare electrocoagulation prior to Nd:YAG laser photocoagulation in 85 voluminous colorectal villous adenomas.

PubMed

Aubert, A; Meduri, B; Fritsch, J; Aime, F; Baglin, A; Barbagelata, M

1991-05-01

The association of endoscopic resection with Nd:YAG laser photocoagulation was used to treat benign colorectal villous adenomas. Eight-five patients were included: 49 with surgical contraindications, 35 for whom surgical resection appeared to be too hazardous, and 1 who refused surgery. Forty-five tumors had an axial extension between 1 and 3 cm, and 40 tumors had an axial extension of at least 4 cm. Diathermic snare resection was performed to remove large tumoral fragments prior to laser photocoagulation of the residual flat lesions. Treatments were repeated every 15 days until total tumor destruction was achieved. A carcinoma was detected in biopsy specimens obtained during endoscopic treatment of five patients. Two patients were lost to follow-up. Treatment results could be analyzed in 78 patients. Successful treatment was achieved in 67 patients. Tumor destruction was complete in 77 percent of patients who had lesions of at least 4 cm diameter and in 93 percent of patients with smaller lesions. The axial extension of the tumor was the main factor affecting the results of treatment. No major complications occurred. During the average 103-week follow-up period, 21 percent of the patients with total tumor destruction had a recurrence. The risk of recurrence was correlated with the number of initial treatment sessions and previous surgery treatment. It would appear that the treatment with endoscopic resection prior to Nd:YAG laser photocoagulation is a safe and effective method in the destruction of colorectal villous adenomas.

Membrane translocation of t-SNARE protein syntaxin-4 abrogates ground-state pluripotency in mouse embryonic stem cells

PubMed Central

Hagiwara-Chatani, Natsumi; Shirai, Kota; Kido, Takumi; Horigome, Tomoatsu; Yasue, Akihiro; Adachi, Naoki; Hirai, Yohei

2017-01-01

Embryonic stem (ES) and induced pluripotent stem (iPS) cells are attractive tools for regenerative medicine therapies. However, aberrant cell populations that display flattened morphology and lose ground-state pluripotency often appear spontaneously, unless glycogen synthase kinase 3β (GSK3β) and mitogen-activated protein kinase kinase (MEK1/2) are inactivated. Here, we show that membrane translocation of the t-SNARE protein syntaxin-4 possibly is involved in this phenomenon. We found that mouse ES cells cultured without GSK3β/MEK1/2 inhibitors (2i) spontaneously extrude syntaxin-4 at the cell surface and that artificial expression of cell surface syntaxin-4 induces appreciable morphological changes and mesodermal differentiation through dephosphorylation of Akt. Transcriptome analyses revealed several candidate elements responsible for this, specifically, an E-to P-cadherin switch and a marked downregulation of Zscan4 proteins, which are DNA-binding proteins essential for ES cell pluripotency. Embryonic carcinoma cell lines F9 and P19CL6, which maintain undifferentiated states independently of Zscan4 proteins, exhibited similar cellular behaviors upon stimulation with cell surface syntaxin-4. The functional ablation of E-cadherin and overexpression of P-cadherin reproduced syntaxin-4-induced cell morphology, demonstrating that the E- to P-cadherin switch executes morphological signals from cell surface syntaxin-4. Thus, spontaneous membrane translocation of syntaxin-4 emerged as a critical element for maintenance of the stem-cell niche. PMID:28057922

Treatment of type II endoleak using Onyx with long-term imaging follow-up.

PubMed

Khaja, Minhaj S; Park, Auh Whan; Swee, Warren; Evans, Avery J; Fritz Angle, J; Turba, Ulku C; Sabri, Saher S; Matsumoto, Alan H

2014-06-01

The purpose of our study is to report our experience with the use of an ethylene vinyl alcohol copolymer (Onyx) in an off-label fashion for the treatment of type II endoleak after endovascular repair of the thoracic (TEVAR) and abdominal (EVAR) aorta. A retrospective review of patients with type I and/or II endoleak treated with Onyx was performed. Data regarding the technical, clinical, and imaging outcomes were collected. Technical success was defined as decreased or eliminated endoleak on the first imaging follow-up. Clinical success was defined as unchanged or decreased aneurysm sac size on subsequent follow-up. Eighteen patients (15 male, 3 female) with a mean age of 79 years (range 69-92) met inclusion criteria (16 abdominal aortic aneurysm, 2 thoracic aortic aneurysm). Sixteen patients had type II endoleak, and 2 had complex type II endoleak with a type I component. The interval between endograft placement and treatment was a mean of 30 months. Direct sac treatment approach was used in 13 patients; transarterial approach was used in 3 patients. Seven patients required the use of coils, N-butyl cyanoacrylate glue, or Amplatzer vascular plugs. The average volume of Onyx used per treatment was 5.6 mL (range 2.5-13). Duration of imaging follow-up was 0.75-72.5 months (mean 32.8). Sixteen of 18 (88.9 %) patients had initial technical and clinical success. Two of 18 patients (11.1 %) were initial technical failures, and 1 remained a failure despite a second treatment and attempted surgical ligation. Eight of 18 (44.4 %) of patients eventually required a second intervention, 5 (27.8 %) of them due to delayed clinical failure. Complications included 1 psoas hematoma, 1 transient L2 nerve paresis, and 1 intraperitoneal Onyx leak; all of these were without clinical sequelae. Onyx with or without coil/glue/Amplatzer plug embolization is safe and useful in the treatment of type II endoleak after TEVAR and EVAR. However, long-term clinical and imaging follow-up is needed for early detection and management of recurrence of the primary endoleak or the development of new, secondary endoleaks or enlargement of the aneurysm sac.

Percutaneous left atrial appendage occlusion for stroke prevention in patients with atrial fibrillation and contraindication for anticoagulation.

PubMed

Grosset-Janin, D; Barth, E; Bertrand, B; Detante, O

2015-05-01

Stroke, as the third cause of death in developed countries, is a public health issue. Atrial fibrillation is an important cause of ischemic stroke and its prevention is efficient with oral anticoagulation. However, oral anticoagulation can be contraindicated because of hemorrhagic risk related to these treatments. Percutaneous left atrial appendage occlusion is a new alternative of oral anticoagulation for patients with atrial fibrillation and high risk of cardio-embolic stroke but contraindicated for oral anticoagulation. We describe in this paper the procedure of left atrial appendage occlusion with the Amplatzer cardiac plug device, used in our center in Grenoble university hospital, for the first three patients who have been treated with this device. These three patients (one man and two women) have all atrial fibrillation with neurological complication of this arrhythmia, as ischemic stroke. Oral anticoagulation is indicated to prevent another ischemic stroke. However, they all have a high risk of cerebral bleeding for different reasons (cavernomatosis, history of intracerebral hemorrhage and aneurysm of the polygon of Willis). Consequently, they have a high risk of cardio-embolic complication but contraindication for oral anticoagulation. They have been treated by left atrial appendage occlusion with Amplatzer cardiac plug device by percutaneous and trans-septal access. Then, they have been followed by neurologist and cardiologist, with clinical and paraclinical evaluation by echocardiography. Our three first patients have been successfully implanted, without periprocedural complication. No latest adverse event was observed, and particularly no cardiac or neurologic adverse event. The technique of left atrial appendage occlusion is a very interesting and promising technique for ischemic stroke prevention in patient with high risk of cardio-embolic complication because of atrial fibrillation, but high risk of bleeding and contraindication for oral anticoagulation. Because of frequency of both atrial fibrillation and contraindication for oral anticoagulation, occlusion of the left atrial appendage should become an interesting alternative for many patients. However, it remains an invasive procedure and efficacy and indications need to be evaluated in further clinical trials. Risk/benefit ratio must be carefully assessed and compared to that of the new anticoagulant drugs. Copyright © 2015. Published by Elsevier Masson SAS.

Fingered bola body, bola with same, and methods of use

NASA Technical Reports Server (NTRS)

Dzenitis, John M. (Inventor); Billica, Linda W. (Inventor)

1994-01-01

The present invention discloses bola bodies, bolas, and a snaring method which makes use such devices. A bola body, according to the present invention, is nonspherical or irregular in shape rather than a smooth sphere or ovoid body. One or more fingers extends from the bola body. These fingers may be relatively straight or they may have crooked or bent portions to enhance entanglement with a bola line or lines or with each other. Two or more of such fingers may be used and may be regularly or irregularly spaced apart on a bola body. A bola with such bodies includes lines which are connected to the other bodies. In one particular embodiment of a bola body, according to the present invention, the body has an irregular shape with a bottom rectangular portion and a top pyramid portion forming a nose. A plurality of fingers is extended from the pyramidal top portion with one finger extended up and away from each of four corners of the top portion. Such a bola body tends to be initially oriented with its nose and fingers against an object being snared since the body is pulled nose first when a bola line is secured at the tip of the pyramidal portion of the bola body. With such a bola, an unwrapping bola body can slip around a target member so that two of the rod-shaped fingers catch a bola line and guide it into an area or crook between the fingers and a side of the top pyramidal portion of the bola body. Tension on the bola line maintains the line in the crook and tends to press the fingers against the unwrapped target member to stabilize the wrapping of the line about the target member. With such a bola, it is difficult for two or more lines unwrapping in different directions to move past one another without being forced together by line tension. Also, the fingers of such bola bodies may hook and hold each other. The fingers may also hook or entangle some object on or portion of the target member. A probable known target member has known dimensions and shapes so that the bola may be sized and configured to reliably snare such a known target. The bolas can be optimally sized, fashioned, and configured to contact and hold a probable target of known size, dimension, and shape.

A Novel Technique for Inferior Vena Cava Filter Extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnston, Edward William, E-mail: ed.johnston@doctors.org.uk; Rowe, Luke Michael Morgan; Brookes, Jocelyn

Inferior vena cava (IVC) filters are used to protect against pulmonary embolism in high-risk patients. Whilst the insertion of retrievable IVC filters is gaining popularity, a proportion of such devices cannot be removed using standard techniques. We describe a novel approach for IVC filter removal that involves snaring the filter superiorly along with the use of flexible forceps or laser devices to dissect the filter struts from the caval wall. This technique has used to successfully treat three patients without complications in whom standard techniques failed.

Steam-deformed Judkins-left guiding catheter with use of the GuideLiner(®) catheter to deliver stents for anomalous right coronary artery.

PubMed

Kuno, Toshiki; Fujisawa, Taishi; Yamazaki, Hiroyuki; Motoda, Hiroyuki; Kodaira, Masaki; Numasawa, Yohei

2015-01-01

Percutaneous coronary intervention for anomalous right coronary artery (RCA) originating from the left coronary cusp is challenging because of our current inability to coaxially engage the guiding catheter. We report a case of an 88-year-old woman with non-ST segment elevation myocardial infarction, with an anomalous RCA origin. Using either the Judkins-Left catheter or Amplatz-Left catheter was difficult because of RCA ostium tortuosity. Thus, we used steam to deform the Judkins-Left catheter, but back-up support was insufficient to deliver the stent. We used GuideLiner®, a novel pediatric catheter with rapid exchange/monorail systems, to enhance back-up support. We were able to successfully stent with both the deformed Judkins-Left guiding catheter and GuideLiner® for an anomalous RCA origin.

Mitral valve replacement complicated by iatrogenic left ventricular outflow obstruction and paravalvular leak: case report and review of literature.

PubMed

Lee, Justin Z; Tey, Kai R; Mizyed, Ahmad; Hennemeyer, Charles T; Janardhanan, Rajesh; Lotun, Kapildeo

2015-10-09

Left ventricular outflow tract (LVOT) obstruction and paravalvular leak (PVL) are relatively uncommon, but are serious complications of prosthetic valve replacement. We present a case that displays the unique therapeutic challenges of treating a patient who developed both LVOT obstruction and mitral PVL after undergoing surgical aortic and mitral valve replacement (MVR). We also describe the use of alcohol septal ablation and albumin-glutaraldehyde (BioGlue) for septal ablation to percutaneously treat the patient's LVOT obstruction, followed by use of an Amplatzer vascular plug for percutaneous closure of an antero-medial mitral PVL associated with severe regurgitation. Percutaneous interventional management of these entities may be considered as an initial therapeutic option, especially in high-risk patients with significant morbidity and mortality of repeat surgical operations.

Transseptal Guidewire Stabilization for Device Closure of a Large Pulmonary Arteriovenous Malformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph, George, E-mail: joseph59@gmail.com; Kunwar, Brajesh Kumar, E-mail: kunwar_brajesh@yahoo.com

A 46-year-old man presenting with massive hemoptysis was found to have a large pulmonary arteriovenous malformation (PAVM) in the right lung. Closure of the PAVM with an Amplatzer-type duct occluder was hampered by inability to advance the device delivery sheath into the PAVM due to vessel tortuosity and inadequate guidewire support. Atrial septal puncture was performed and a femorofemoral arteriovenous guidewire loop through the right pulmonary artery, PAVM, and left atrium was created. Traction on both ends of the guidewire loop allowed advancement of the device delivery sheath into the PAVM and successful completion of the procedure. Transseptal guidewire stabilizationmore » can be a valuable option during device closure of large PAVMs when advancement, stability, or kinking of the device delivery sheath is an issue.« less

A novel drainage technique during micropercutaneous nephrolithotomy in pediatric patients: double angiocath.

PubMed

Penbegul, Necmettin; Utangac, Mehmet Mazhar; Daggulli, Mansur; Dede, Onur; Bozkurt, Yasar; Bodakci, Mehmet Nuri; Atar, Murat

2016-06-01

Micropercutaneous nephrolithotomy (microperc) is a recently introduced percutaneous nephrolithotomy (PNL) technique that has the smallest tract size. The absence of an amplatz sheath during the microperc technique is a fundamental difference that distinguishes it from all other types of PNL (standard, mini, ultramini). Increasing of the intrarenal pelvic pressure (IPP) was demonstrated by the authors in adult patients but this problem may be even more serious in pediatric patients. Previously, the authors defined the use of a 14 gauge angiocath needle and sheath (microsheath) during microperc surgery for pediatric patient to reduce the IPP. In this novel technique, a second angiocath is used to access the renal collecting system to drain fluid during surgery. This technique is more effective in reducing IPP during microperc, especially in pediatric patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Vesicle-associated membrane protein 2 mediates trafficking of {alpha}5{beta}1 integrin to the plasma membrane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasan, Nazarul; Hu, Chuan, E-mail: chuan.hu@louisville.edu

2010-01-01

Integrins are major receptors for cell adhesion to the extracellular matrix (ECM). As transmembrane proteins, the levels of integrins at the plasma membrane or the cell surface are ultimately determined by the balance between two vesicle trafficking events: endocytosis of integrins at the plasma membrane and exocytosis of the vesicles that transport integrins. Here, we report that vesicle-associated membrane protein 2 (VAMP2), a SNARE protein that mediates vesicle fusion with the plasma membrane, is involved in the trafficking of {alpha}5{beta}1 integrin. VAMP2 was present on vesicles containing endocytosed {beta}1 integrin. Small interfering RNA (siRNA) silencing of VAMP2 markedly reduced cellmore » surface {alpha}5{beta}1 and inhibited cell adhesion and chemotactic migration to fibronectin, the ECM ligand of {alpha}5{beta}1, without altering cell surface expression of {alpha}2{beta}1 integrin or {alpha}3{beta}1 integrin. By contrast, silencing of VAMP8, another SNARE protein, had no effect on cell surface expression of the integrins or cell adhesion to fibronectin. In addition, VAMP2-mediated trafficking is involved in cell adhesion to collagen but not to laminin. Consistent with disruption of integrin functions in cell proliferation and survival, VAMP2 silencing diminished proliferation and triggered apoptosis. Collectively, these data indicate that VAMP2 mediates the trafficking of {alpha}5{beta}1 integrin to the plasma membrane and VAMP2-dependent integrin trafficking is critical in cell adhesion, migration and survival.« less

The other prey-capture silk: Fibres made by glow-worms (Diptera: Keroplatidae) comprise cross-β-sheet crystallites in an abundant amorphous fraction.

PubMed

Walker, Andrew A; Weisman, Sarah; Trueman, Holly E; Merritt, David J; Sutherland, Tara D

2015-09-01

Glow-worms (larvae of dipteran genus Arachnocampa) are restricted to moist habitats where they capture flying prey using snares composed of highly extensible silk fibres and sticky mucus droplets. Little is known about the composition or structure of glow-worm snares, or the extent of possible convergence between glow-worm and arachnid capture silks. We characterised Arachnocampa richardsae silk and mucus using X-ray scattering, Fourier transform infrared spectroscopy and amino acid analysis. Silk but not mucus contained crystallites of the cross-β-sheet type, which occur in unrelated insect silks but have not been reported previously in fibres used for prey capture. Mucus proteins were rich in Gly (28.5%) and existed in predominantly a random coil structure, typical of many adhesive proteins. In contrast, the silk fibres were unusually rich in charged and polar residues, particularly Lys (18.1%), which we propose is related to their use in a highly hydrated state. Comparison of X-ray scattering, infrared spectroscopy and amino acid analysis data suggests that silk fibres contain a high fraction of disordered protein. We suggest that in the native hydrated state, silk fibres are capable of extension via deformation of both disordered regions and cross-β-sheet crystallites, and that high extensibility is an adaptation promoting successful prey capture. This study illustrates the rich variety of protein motifs that are available for recruitment into biopolymers, and how convergently evolved materials can nevertheless be based on fundamentally different protein structures. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Impairment of autophagosome-lysosome fusion in the buff mutant mice with the VPS33AD251E mutation

PubMed Central

Zhen, Yuanli; Li, Wei

2015-01-01

The HOPS (homotypic fusion and protein sorting) complex functions in endocytic and autophagic pathways in both lower eukaryotes and mammalian cells through its involvement in fusion events between endosomes and lysosomes or autophagosomes and lysosomes. However, the differential molecular mechanisms underlying these fusion processes are largely unknown. Buff (bf) is a mouse mutant that carries an Asp251-to-Glu point mutation (D251E) in the VPS33A protein, a tethering protein and a core subunit of the HOPS complex. Bf mice showed impaired spontaneous locomotor activity, motor learning, and autophagic activity. Although the gross anatomy of the brain was apparently normal, the number of Purkinje cells was significantly reduced. Furthermore, we found that fusion between autophagosomes and lysosomes was defective in bf cells without compromising the endocytic pathway. The direct association of mutant VPS33AD251E with the autophagic SNARE complex, STX17 (syntaxin 17)-VAMP8-SNAP29, was enhanced. In addition, the VPS33AD251E mutation enhanced interactions with other HOPS subunits, namely VPS41, VPS39, VPS18, and VPS11, except for VPS16. Reduction of the interactions between VPS33AY440D and several other HOPS subunits led to decreased association with STX17. These results suggest that the VPS33AD251E mutation plays dual roles by increasing the HOPS complex assembly and its association with the autophagic SNARE complex, which selectively affects the autophagosome-lysosome fusion that impairs basal autophagic activity and induces Purkinje cell loss. PMID:26259518

Characterization of phospholipids in insulin secretory granules and mitochondria in pancreatic beta cells and their changes with glucose stimulation.

PubMed

MacDonald, Michael J; Ade, Lacmbouh; Ntambi, James M; Ansari, Israr-Ul H; Stoker, Scott W

2015-04-24

The lipid composition of insulin secretory granules (ISG) has never previously been thoroughly characterized. We characterized the phospholipid composition of ISG and mitochondria in pancreatic beta cells without and with glucose stimulation. The phospholipid/protein ratios of most phospholipids containing unsaturated fatty acids were higher in ISG than in whole cells and in mitochondria. The concentrations of negatively charged phospholipids, phosphatidylserine, and phosphatidylinositol in ISG were 5-fold higher than in the whole cell. In ISG phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin, fatty acids 12:0 and 14:0 were high, as were phosphatidylserine and phosphatidylinositol containing 18-carbon unsaturated FA. With glucose stimulation, the concentration of many ISG phosphatidylserines and phosphatidylinositols increased; unsaturated fatty acids in phosphatidylserine increased; and most phosphatidylethanolamines, phosphatidylcholines, sphingomyelins, and lysophosphatidylcholines were unchanged. Unsaturation and shorter fatty acid length in phospholipids facilitate curvature and fluidity of membranes, which favors fusion of membranes. Recent evidence suggests that negatively charged phospholipids, such as phosphatidylserine, act as coupling factors enhancing the interaction of positively charged regions in SNARE proteins in synaptic or secretory vesicle membrane lipid bilayers with positively charged regions in SNARE proteins in the plasma membrane lipid bilayer to facilitate docking of vesicles to the plasma membrane during exocytosis. The results indicate that ISG phospholipids are in a dynamic state and are consistent with the idea that changes in ISG phospholipids facilitate fusion of ISG with the plasma membrane-enhancing glucose-stimulated insulin exocytosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Subduction Initiation under Unfavorable Conditions and New Fault Formation

NASA Astrophysics Data System (ADS)

Mao, X.; Gurnis, M.; May, D.

2017-12-01

How subduction initiates with unfavorable dipping lithospheric heterogeneities is an important and rarely studied topic. We build a geodynamic model starting with a vertical weak zone for the Puysegur incipient subduction zone (PISZ). A true free surface is tracked in pTatin3D, based on the Arbitrary Lagrangian Eulerian (ALE) finite element method, and is used to follow the dynamic mantle-surface interaction and topographic evolution. A simplified surface process, based on linear topography diffusion, is implemented. Density and free water content for different phase assemblages are gained by referring to precalculated 4D (temperature, pressure, rock type and total water content) phase maps using Perplex. Darcy's law is used to migrate free water, and a linear water weakening is applied to the mantle material. A new visco-elastic formulation called Elastic Viscous Stress Splitting (EVSS) method is also included. Our predictions fit the morphology of the Puysegur Trench and Ridge and the deformation history on the overriding plate. We show a new thrust fault forms and evolves into a smooth subduction interface, and the preexisting weak zone becomes a vertical fault inboard of the thrust fault during subduction initiation, which explains the two-fault system at PISZ. Our model suggests that the PISZ may not yet be self-sustaining. We propose that the Snares Trough is caused by plate coupling differences between shallower and deeper parts, the tectonic sliver between two faults experiences strong rotation, and low density materials accumulate beneath the Snares trough. Extended models show that with favorable dipping heterogeneities, no new fault forms, and subduction initiates with smaller resisting forces.

Pediatric foreign bodies and their management.

PubMed

Kay, Marsha; Wyllie, Robert

2005-06-01

Ingestion of foreign bodies is a common pediatric problem, with more than 100,000 cases occurring each year. The vast majority of pediatric ingestions are accidental; increasing incidence of intentional ingestions starts in the adolescent age group. In the United States, the most common pediatric foreign bodies ingested are coins, followed by a variety of other objects, including toys, toy parts, sharp objects, batteries, bones, and food. In adolescents and adults, meat or food impactions are the most common accidental foreign body ingestion. Esophageal pathology underlies most cases of food impaction. Management of foreign body ingestions varies based on the object ingested, its location, and the patient's age and size. Esophageal foreign bodies as a group require early intervention because of their potential to cause respiratory symptoms and complications, esophageal erosions, or even an aortoesophageal fistula. Ingested batteries that lodge in the esophagus require urgent endoscopic removal even in the asymptomatic patient due to the high risk of complications. Sharp foreign bodies increase the foreign body complication rate from less than 1% to 15% to 35%, except for straight pins, which usually follow a relatively benign course unless multiple pins are ingested. Magnets are increasingly ingested, due to their ubiquitous nature and the perception that they do not pose a risk. Ingestion of multiple magnets creates a significant risk of obstruction, perforation, and fistula development. Methods to deal with foreign bodies include the suture technique, the double snare technique, and the combined forceps/snare technique for long, large, and sharp foreign bodies, along with newer equipment, such as retrieval nets and a variety of specialized forceps.

Environmental DNA from Residual Saliva for Efficient Noninvasive Genetic Monitoring of Brown Bears (Ursus arctos)

PubMed Central

Wheat, Rachel E.; Allen, Jennifer M.; Miller, Sophie D. L.; Wilmers, Christopher C.; Levi, Taal

2016-01-01

Noninvasive genetic sampling is an important tool in wildlife ecology and management, typically relying on hair snaring or scat sampling techniques, but hair snaring is labor and cost intensive, and scats yield relatively low quality DNA. New approaches utilizing environmental DNA (eDNA) may provide supplementary, cost-effective tools for noninvasive genetic sampling. We tested whether eDNA from residual saliva on partially-consumed Pacific salmon (Oncorhynchus spp.) carcasses might yield suitable DNA quality for noninvasive monitoring of brown bears (Ursus arctos). We compared the efficiency of monitoring brown bear populations using both fecal DNA and salivary eDNA collected from partially-consumed salmon carcasses in Southeast Alaska. We swabbed a range of tissue types from 156 partially-consumed salmon carcasses from a midseason run of lakeshore-spawning sockeye (O. nerka) and a late season run of stream-spawning chum (O. keta) salmon in 2014. We also swabbed a total of 272 scats from the same locations. Saliva swabs collected from the braincases of salmon had the best amplification rate, followed by swabs taken from individual bite holes. Saliva collected from salmon carcasses identified unique individuals more quickly and required much less labor to locate than scat samples. Salmon carcass swabbing is a promising method to aid in efficient and affordable monitoring of bear populations, and suggests that the swabbing of food remains or consumed baits from other animals may be an additional cost-effective and valuable tool in the study of the ecology and population biology of many elusive and/or wide-ranging species. PMID:27828988

Polidocanol injection decreases the bleeding rate after colon polypectomy: a propensity score analysis.

PubMed

Facciorusso, Antonio; Di Maso, Marianna; Antonino, Matteo; Del Prete, Valentina; Panella, Carmine; Barone, Michele; Muscatiello, Nicola

2015-08-01

EMR is the standard of care for the resection of large polyps. To compare the efficacy and safety profile of submucosal polidocanol injection with epinephrine-saline solution injection for colon polypectomy with a diathermic snare. After 1-to-1 propensity score caliper matching, comparison of submucosal epinephrine injection was performed with polidocanol injection. Endoscopic suite at the University of Foggia between 2005 and 2014. Of 711 patients who underwent endoscopic resection of colon sessile polyps 20 mm or larger, 612 were analyzed after matching. Submucosal epinephrine injection in 306 patients and polidocanol injection in 306 patients. Univariate and multivariate logistic regression models aimed at identifying independent predictors of postpolypectomy bleeding (PPB). The 2 groups presented similar baseline clinical parameters and lesion characteristics. All patients had a single polyp 20 mm or larger; the median size was 32 mm (interquartile range [IQR], 25-38) in the polidocanol group and 32 (IQR, 24-38) in the epinephrine group (P=.7). Polidocanol was more effective in preventing both immediate and delayed PPB (P<.001 and P=.003, respectively), and its efficacy was confirmed in almost all of the subgroups, regardless of polyp size and histology. Postprocedure perforation was observed in 2 patients (0.3%), both in the epinephrine group (P=.49). The 2 groups did not differ in the number of snare resections of lesions or the procedure duration (P=.24 and .6, respectively). Absence of randomization. The submucosal injection of polidocanol for colon EMR is effective and significantly lowers the PPB rate. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Effect of cholesterol depletion on exocytosis of alveolar type II cells.

PubMed

Chintagari, Narendranath Reddy; Jin, Nili; Wang, Pengcheng; Narasaraju, Telugu Akula; Chen, Jiwang; Liu, Lin

2006-06-01

Alveolar epithelial type II cells secrete lung surfactant via exocytosis. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) are implicated in this process. Lipid rafts, the cholesterol- and sphingolipid-rich microdomains, may offer a platform for protein organization on the cell membrane. We tested the hypothesis that lipid rafts organize exocytotic proteins in type II cells and are essential for the fusion of lamellar bodies, the secretory granules of type II cells, with the plasma membrane. The lipid rafts, isolated from type II cells using 1% Triton X-100 and a sucrose gradient centrifugation, contained the lipid raft markers, flotillin-1 and -2, whereas they excluded the nonraft marker, Na+-K+ ATPase. SNAP-23, syntaxin 2, and VAMP-2 were enriched in lipid rafts. When type II cells were depleted of cholesterol, the association of SNAREs with the lipid rafts was disrupted and the formation of fusion pore was inhibited. Furthermore, the cholesterol-depleted plasma membrane had less ability to fuse with lamellar bodies, a process mediated by annexin A2. The secretagogue-stimulated secretion of lung surfactant from type II cells was also reduced by methyl-beta-cyclodextrin. When the raft-associated cell surface protein, CD44, was cross-linked using anti-CD44 antibodies, the CD44 clusters were observed. Syntaxin 2, SNAP-23, and annexin A2 co-localized with the CD44 clusters, which were cholesterol dependent. Our results suggested that lipid rafts may form a functional platform for surfactant secretion in alveolar type II cells, and raft integrity was essential for the fusion between lamellar bodies with the plasma membrane.

AMPA antagonist LY293558 does not affect the severity of hypoxic-ischemic injury in newborn pigs.

PubMed

LeBlanc, M H; Li, X Q; Huang, M; Patel, D M; Smith, E E

1995-10-01

LY293558 is a systemically active alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) excitatory amino acid antagonist. AMPA antagonists have shown promise in several adult hypoxic-ischemic brain injury models, and we wanted to see if this work could be extended to a newborn animal. Seventy-six (beta error < .10) 0- to 3-day-old piglets under 1.5% isoflurane anesthesia underwent placement of carotid snares and arterial and venous catheters. While paralyzed with succinylcholine under 0.5% isoflurane, 50% nitrous oxide, piglets were randomly assigned to receive either 5 mg/kg or 15 mg/kg of LY293558 or saline at time--10 minutes and again 10 hours later. At time 0, both carotid arteries were clamped, and blood was withdrawn to reduce the blood pressure to two thirds of normal. At time 15 minutes, inspired oxygen was reduced to 6%. At time 30 minutes, the carotid snares were released, the withdrawn blood was reinfused, and the oxygen was switched to 100%. On the third day after the hypoxic-ischemic injury, the animals were killed by perfusion of the brain with 10% formalin. Brain pathology was scored by a blinded observer. There were no significant differences between the drug-treated and control groups. The systemically active AMPA antagonist LY293558, when given at a dose of 5 mg/kg or 15 mg/kg before injury and 10 hours later, does not affect the severity of hypoxic-ischemic brain injury in newborn piglets. Neither AMPA receptor activity nor NMDA receptor activity are important in brain injury in this model.

Gq-DREADD Selectively Initiates Glial Glutamate Release and Inhibits Cue-induced Cocaine Seeking

PubMed Central

Scofield Michael, D.; Boger Heather, A.; Smith Rachel, J.; Li, Hao; Haydon Philip, G.; Kalivas Peter, W.

2015-01-01

Background Glial cells of the central nervous system directly influence neuronal activity by releasing neuroactive small molecules, including glutamate. Long-lasting cocaine-induced reductions in extracellular glutamate in the nucleus accumbens core (NAcore) affect synaptic plasticity responsible for relapse vulnerability. Methods We transduced NAcore astrocytes with an AAV viral vector expressing hM3Dq (Gq) DREADD under control of the glial fibrillary acidic protein (GFAP) promoter in 62 male Sprague Dawley rats, 4 dnSNARE mice and 4 wild type littermates. Using glutamate biosensors we measured NAcore glutamate levels following intracranial or systemic administration of clozapine-N-oxide (CNO), and tested the ability of systemic CNO to inhibit reinstated cocaine or sucrose seeking following self-administration (SA) and extinction training. Results Administration of CNO in GFAP-Gq-DREADD transfected animals increased NAcore extracellular glutamate levels in vivo. The glial origin of released glutamate was validated by an absence of CNO-mediated release in mice expressing a dominant-negative SNARE variant in glia. Also, CNO-mediated release was relatively insensitive to N-type calcium channel blockade. Systemic administration of CNO inhibited cue-induced reinstatement of cocaine seeking in rats extinguished from cocaine, but not sucrose SA. The capacity to inhibit reinstated cocaine-seeking was prevented by systemic administration of the group II metabotropic glutamate receptor (mGluR2/3) antagonist LY341495. Conclusions DREADD-mediated glutamate gliotransmission inhibited cue-induced reinstatement of cocaine seeking by stimulating release-regulating mGluR2/3 autoreceptors to inhibit cue-induced synaptic glutamate spillover. PMID:25861696

Endoplasmatic reticulum shaping by generic mechanisms and protein-induced spontaneous curvature.

PubMed

Sackmann, Erich

2014-06-01

The endoplasmatic reticulum (ER) comprises flattened vesicles (cisternae) with worm holes dubbed with ribosomes coexisting with a network of interconnected tubes which can extend to the cell periphery or even penetrate nerve axons. The coexisting topologies enclose a continuous luminal space. The complex ER topology is specifically controlled by a group of ER-shaping proteins often called reticulons (discovered by the group of Tom Rapoport). They include atlastin, reticulon, REEP and the MT severing protein spastin. A generic ER shape controlling factor is the necessity to maximize the area-to-volume ratio of ER membranes in the highly crowded cytoplasmic space. I present a model of the ER-shaping function of the reticulons based on the Helfrich bending elasticity concept of soft shell shape changes. Common structural motifs of the reticulons are hydrophobic sequences forming wedge shaped hairpins which penetrate the lipid bilayer of the cell membranes. The wedge-like hydrophobic anchors can both induce the high curvature of the tubular ER fraction and ensure the preferred distribution of the reticulons along the tubules. Tubular junctions may be stabilized by the reticulons forming two forceps twisted by 90°. The ER extensions to the cell periphery and the axons are mediated by coupling of the tubes to the microtubules which is mediated by REEP and spastin. At the end I present a model of the tension driven homotype fusion of ER-membranes by atlastin, based on analogies to the SNARE-complexin-SNARE driven heterotype fusion process. Copyright © 2014 Elsevier B.V. All rights reserved.

Structural And Biochemical Studies of Botulinum Neurotoxin Serotype C1 Light Chain Protease: Implications for Dual Substrate Specificity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, R.; Sikorra, S.; Stegmann, C.M.

2009-06-01

Clostridial neurotoxins are the causative agents of the neuroparalytic disease botulism and tetanus. They block neurotransmitter release through specific proteolysis of one of the three soluble N-ethylmaleimide-sensitive-factor attachment protein receptors (SNAREs) SNAP-25, syntaxin, and synaptobrevin, which constitute part of the synaptic vesicle fusion machinery. The catalytic component of the clostridial neurotoxins is their light chain (LC), a Zn2+ endopeptidase. There are seven structurally and functionally related botulinum neurotoxins (BoNTs), termed serotype A to G, and tetanus neurotoxin (TeNT). Each of them exhibits unique specificity for their target SNAREs and peptide bond(s) they cleave. The mechanisms of action for substrate recognitionmore » and target cleavage are largely unknown. Here, we report structural and biochemical studies of BoNT/C1-LC, which is unique among BoNTs in that it exhibits dual specificity toward both syntaxin and SNAP-25. A distinct pocket (S1') near the active site likely achieves the correct register for the cleavage site by only allowing Ala as the P1' residue for both SNAP-25 and syntaxin. Mutations of this SNAP-25 residue dramatically reduce enzymatic activity. The remote a-exosite that was previously identified in the complex of BoNT/A-LC and SNAP-25 is structurally conserved in BoNT/C1. However, mutagenesis experiments show that the a-exosite of BoNT/C1 plays a less stringent role in substrate discrimination in comparison to that of BoNT/A, which could account for its dual substrate specificity.« less

Single Molecule Measurements of Interaction Free Energies Between the Proteins Within Binary and Ternary SNARE Complexes

PubMed Central

Liu, W.; Montana, Vedrana; Parpura, Vladimir; Mohideen, U.

2010-01-01

We use an Atomic Force Microscope based single molecule measurements to evaluate the activation free energy in the interaction of SNARE proteins syntaxin 1A, SNAP25B and synaptobrevin 2 which regulate intracellular fusion of vesicles with target membranes. The dissociation rate of the binary syntaxin-synaptobrevin and the ternary syntaxin-SNAP25B-synaptobrevin complex was measured from the rupture force distribution as a function of the rate of applied force. The temperature dependence of the spontaneous dissociation rate was used to obtain the activation energy to the transition state of 19.8 ± 3.5 kcal/mol = 33 ± 6 kBT and 25.7 ± 3.0 kcal/mol = 43 ± 5 kBT for the binary and ternary complex, respectively. They are consistent with those measured previously for the ternary complex in lipid membranes and are of order expected for bilayer fusion and pore formation. The ΔG was 12.4–16.6 kcal/mol = 21–28 kBT and 13.8–18.0 kcal/mol = 23–30 kBT for the binary and ternary complex, respectively. The ternary complex was more stable by 1.4 kcal/mol = 2.3 kBT, consistent with the spontaneous dissociation rates. The higher adhesion energies and smaller molecular extensions measured with SNAP25B point to its possible unique and important physiological role in tethering/docking the vesicle in closer proximity to the plasma membrane and increasing the probability for fusion completion. PMID:20107522

An Endovascular Approach to the Entrapped Central Venous Catheter After Cardiac Surgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desai, Shamit S., E-mail: shamit.desai@northwestern.edu; Konanur, Meghana; Foltz, Gretchen

PurposeEntrapment of central venous catheters (CVC) at the superior vena cava (SVC) cardiopulmonary bypass cannulation site by closing purse-string sutures is a rare complication of cardiac surgery. Historically, resternotomy has been required for suture release. An endovascular catheter release approach was developed.Materials and MethodsFour cases of CVC tethering against the SVC wall and associated resistance to removal, suggestive of entrapment, were encountered. In each case, catheter removal was achieved using a reverse catheter fluoroscopically guided over the suture fixation point between catheter and SVC wall, followed by the placement of a guidewire through the catheter. The guidewire was snared andmore » externalized to create a through-and-through access with the apex of the loop around the suture. A snare placed from the femoral venous access provided concurrent downward traction on the distal CVC during suture release maneuvers.ResultsIn the initial attempt, gentle traction freed the CVC, which fractured and was removed in two sections. In the subsequent three cases, traction alone did not release the CVC. Therefore, a cutting balloon was introduced over the guidewire and inflated. Gentle back-and-forth motion of the cutting balloon atherotomes successfully incised the suture in all three attempts. No significant postprocedural complications were encountered. During all cases, a cardiovascular surgeon was present in the interventional suite and prepared for emergent resternotomy, if necessary.ConclusionAn endovascular algorithm to the “entrapped CVC” is proposed, which likely reduces risks posed by resternotomy to cardiac surgery patients in the post-operative period.« less

Botulinum and Tetanus Neurotoxin-Induced Blockade of Synaptic Transmission in Networked Cultures of Human and Rodent Neurons

PubMed Central

Beske, Phillip H.; Bradford, Aaron B.; Grynovicki, Justin O.; Glotfelty, Elliot J.; Hoffman, Katie M.; Hubbard, Kyle S.; Tuznik, Kaylie M.; McNutt, Patrick M.

2016-01-01

Clinical manifestations of tetanus and botulism result from an intricate series of interactions between clostridial neurotoxins (CNTs) and nerve terminal proteins that ultimately cause proteolytic cleavage of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins and functional blockade of neurotransmitter release. Although detection of cleaved SNARE proteins is routinely used as a molecular readout of CNT intoxication in cultured cells, impaired synaptic function is the pathophysiological basis of clinical disease. Work in our laboratory has suggested that the blockade of synaptic neurotransmission in networked neuron cultures offers a phenotypic readout of CNT intoxication that more closely replicates the functional endpoint of clinical disease. Here, we explore the value of measuring spontaneous neurotransmission frequencies as novel and functionally relevant readouts of CNT intoxication. The generalizability of this approach was confirmed in primary neuron cultures as well as human and mouse stem cell-derived neurons exposed to botulinum neurotoxin serotypes A–G and tetanus neurotoxin. The sensitivity and specificity of synaptic activity as a reporter of intoxication was evaluated in assays representing the principal clinical and research purposes of in vivo studies. Our findings confirm that synaptic activity offers a novel and functionally relevant readout for the in vitro characterizations of CNTs. They further suggest that the analysis of synaptic activity in neuronal cell cultures can serve as a surrogate for neuromuscular paralysis in the mouse lethal assay, and therefore is expected to significantly reduce the need for terminal animal use in toxin studies and facilitate identification of candidate therapeutics in cell-based screening assays. PMID:26615023

Identification and Characterization of Botulinum Neurotoxin A Substrate Binding Pockets and Their Re-Engineering for Human SNAP-23.

PubMed

Sikorra, Stefan; Litschko, Christa; Müller, Carina; Thiel, Nadine; Galli, Thierry; Eichner, Timo; Binz, Thomas

2016-01-29

Botulinum neurotoxins (BoNTs) are highly potent bacterial proteins that block neurotransmitter release at the neuromuscular junction by cleaving SNAREs (soluble N-ethyl maleimide sensitive factor attachment protein receptors). However, their serotype A (BoNT/A) that cleaves SNAP-25 (synaptosomal-associated protein of 25 kDa) has also been an established pharmaceutical for treatment of medical conditions that rely on hyperactivity of cholinergic nerve terminals for 25 years. The expansion of its use to a variety of further medical conditions associated with hypersecretion components is prevented partly because the involved SNARE isoforms are not cleaved. Therefore, we examined by mutational analyses the reason for the resistance of human SNAP-23, an isoform of SNAP-25. We show that replacement of 10 SNAP-23 residues with their SNAP-25 counterparts effects SNAP-25-like cleavability. Conversely, transfer of each of the replaced SNAP-23 residues to SNAP-25 drastically decreased the cleavability of SNAP-25. By means of the existing SNAP-25-toxin co-crystal structure, molecular dynamics simulations, and corroborative mutagenesis studies, the appropriate binding pockets for these residues in BoNT/A were characterized. Systematic mutagenesis of two major BoNT/A binding pockets was conducted in order to adapt these pockets to corresponding amino acids of human SNAP-23. Human SNAP-23 cleaving mutants were isolated using a newly established yeast-based screening system. This method may be useful for engineering novel BoNT/A pharmaceuticals for the treatment of diseases that rely on SNAP-23-mediated hypersecretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Resident CAPS on dense-core vesicles docks and primes vesicles for fusion.

PubMed

Kabachinski, Greg; Kielar-Grevstad, D Michelle; Zhang, Xingmin; James, Declan J; Martin, Thomas F J

2016-02-15

The Ca(2+)-dependent exocytosis of dense-core vesicles in neuroendocrine cells requires a priming step during which SNARE protein complexes assemble. CAPS (aka CADPS) is one of several factors required for vesicle priming; however, the localization and dynamics of CAPS at sites of exocytosis in live neuroendocrine cells has not been determined. We imaged CAPS before, during, and after single-vesicle fusion events in PC12 cells by TIRF micro-scopy. In addition to being a resident on cytoplasmic dense-core vesicles, CAPS was present in clusters of approximately nine molecules near the plasma membrane that corresponded to docked/tethered vesicles. CAPS accompanied vesicles to the plasma membrane and was present at all vesicle exocytic events. The knockdown of CAPS by shRNA eliminated the VAMP-2-dependent docking and evoked exocytosis of fusion-competent vesicles. A CAPS(ΔC135) protein that does not localize to vesicles failed to rescue vesicle docking and evoked exocytosis in CAPS-depleted cells, showing that CAPS residence on vesicles is essential. Our results indicate that dense-core vesicles carry CAPS to sites of exocytosis, where CAPS promotes vesicle docking and fusion competence, probably by initiating SNARE complex assembly. © 2016 Kabachinski, Kielar-Grevstad, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Increased Risk Proneness or Social Withdrawal? The Effects of Shortened Life Expectancy on the Expression of Rescue Behavior in Workers of the ant Formica cinerea (Hymenoptera: Formicidae).

PubMed

Miler, Krzysztof; Symonowicz, Beata; Godzińska, Ewa J

2017-01-01

In social insects behavioral consequences of shortened life expectancy include, among others, increased risk proneness and social withdrawal. We investigated the impact of experimental shortening of life expectancy of foragers of the ant Formica cinerea achieved by their exposure to carbon dioxide on the expression of rescue behavior, risky pro-social behavior, tested by means of two bioassays during which a single worker (rescuer) was confronted with a nestmate (victim) attacked by a predator (antlion larva capture bioassay) or immobilized by an artificial snare (entrapment bioassay). Efficacy of carbon dioxide poisoning in shortening life expectancy was confirmed by the analysis of ant mortality. Rescue behavior observed during behavioral tests involved digging around the victim, transport of the sand covering the victim, pulling the limbs/antennae/mandibles of the victim, direct attack on the antlion (in antlion larva capture tests), and snare biting (in entrapment tests). The rate of occurrence of rescue behavior was lower in ants with shortened life expectancy, but that effect was significant only in the case of the entrapment bioassay. Similarly, only in the case of the entrapment bioassay ants with shortened life expectancy displayed rescue behavior after a longer latency and devoted less time to that behavior than ants from the control groups. Our results demonstrated that in ant workers shortened life expectancy may lead to reduced propensity for rescue behavior, most probably as an element of the social withdrawal syndrome that had already been described in several studies on behavior of moribund ants and honeybees.

Noncirrhotic Extrahepatic Portosystemic Shunt Causing Adult-Onset Encephalopathy Treated with Endovascular Closure

PubMed Central

Elnekave, Eldad; Belenky, Eugenia; Van der Veer, Lindsley

2015-01-01

A 54-year-old woman presented with a six-month history of episodic confusion and progressive ataxia. A comprehensive metabolic panel was notable for elevated values of alkaline phosphatase (161 U/L), total bilirubin (1.5 mg/dL), and serum ammonia of 300 umol/L (normal range 9–47). Hepatitis panel, relevant serological tests, tumor markers (CA-19-9, CEA), and urea cycle enzyme studies were unrevealing. Lactulose and rifaximin therapy failed to normalize serum ammonia levels. Imaging revealed a structural vascular abnormality communicating between an enlarged inferior mesenteric vein and the left renal vein, measuring 16 mm in greatest diameter. The diagnosis of congenital extrahepatic portosystemic shunt was made and endovascular shunt closure was performed using a 22 mm Amplatzer II vascular plug. Within a day, serum ammonia levels normalized. Lactulose and rifaximin were discontinued, and confusion and ataxia resolved. PMID:26199783

[Right atrial appendage thrombosis during atrial fibrillation: an element to look for].

PubMed

Barbati, Giovanni; De Domenico, Renato; Rossi, Stefania; Vecchiato, Elena; Zeppellini, Roberto

2017-03-01

Oral anticoagulant therapy (OAT) is a mainstay of atrial fibrillation (AF) pharmacological treatment. Left atrial appendage closure is a possible treatment, when feasible, in patients with intracerebral hemorrhage during OAT. We report a case of right atrial appendage thrombosis in a patient with chronic AF admitted for syncope due to diuretic-induced orthostatic hypotension. Two years previously, he had undergone left atrial appendage closure with the Amplatzer Cardiac Plug device because of intracerebral hemorrhage during OAT. After neurological consult, OAT was resumed with apixaban 5 mg twice daily, and transesophageal echocardiography performed two months later showed complete resolution of the right atrial appendage thrombosis. This particular case underlines the importance of searching for a possible right atrial appendage thrombosis in patients affected by AF, and suggests that left atrial appendage closure in AF patients not suitable for OAT does not fully eliminate the risk of thromboembolism.

Steam-deformed Judkins-left guiding catheter with use of the GuideLiner® catheter to deliver stents for anomalous right coronary artery

PubMed Central

Kuno, Toshiki; Fujisawa, Taishi; Yamazaki, Hiroyuki; Motoda, Hiroyuki; Kodaira, Masaki; Numasawa, Yohei

2015-01-01

Objective: Percutaneous coronary intervention for anomalous right coronary artery (RCA) originating from the left coronary cusp is challenging because of our current inability to coaxially engage the guiding catheter. Methods: We report a case of an 88-year-old woman with non-ST segment elevation myocardial infarction, with an anomalous RCA origin. Using either the Judkins-Left catheter or Amplatz-Left catheter was difficult because of RCA ostium tortuosity. Thus, we used steam to deform the Judkins-Left catheter, but back-up support was insufficient to deliver the stent. Results: We used GuideLiner®, a novel pediatric catheter with rapid exchange/monorail systems, to enhance back-up support. Conclusions: We were able to successfully stent with both the deformed Judkins-Left guiding catheter and GuideLiner® for an anomalous RCA origin. PMID:27489700

Transcatheter closure of a large patent ductus arteriosus using jugular access in an infant.

PubMed

Fernandes, Precylia; Assaidi, Anass; Baruteau, Alban-Elouen; Fraisse, Alain

2018-03-01

Trans-catheter device closure of patent ductus arteriosus (PDA) via femoral route is the commonly used, safe and effective procedure. Trans-jugular approach has been successfully used in older children with interrupted inferior vena cava. We report a case of successful occlusion of PDA using Amplatzer duct occluder (ADO) via trans-jugular approach following difficulties encountered in gaining femoral venous access. A 6-month-old male infant, weighing 8 kg was admitted for percutaneous catheter closure of PDA. Echocardiogram showed a 4.5 mm duct and left heart dilatation. Femoral venous access was not possible; therefore, we decided to use a trans-jugular approach. The duct was occluded using 8/6 mm ADO. Successful closure of the duct was confirmed with an aortogram. Post procedure echocardiogram showed no residual shunt across the duct. We highlight that trans-catheter closure of PDA using jugular venous access is safe and effective even in infants.

Four-color single-molecule fluorescence with noncovalent dye labeling to monitor dynamic multimolecular complexes.

PubMed

DeRocco, Vanessa; Anderson, Trevor; Piehler, Jacob; Erie, Dorothy A; Weninger, Keith

2010-11-01

To enable studies of conformational changes within multimolecular complexes, we present a simultaneous, four-color single molecule fluorescence methodology implemented with total internal reflection illumination and camera-based, wide-field detection. We further demonstrate labeling histidine-tagged proteins noncovalently with Tris-nitrilotriacetic acid (Tris-NTA)-conjugated dyes to achieve single molecule detection. We combine these methods to colocalize the mismatch repair protein MutSα on DNA while monitoring MutSα-induced DNA bending using Förster resonance energy transfer (FRET) and to monitor assembly of membrane-tethered SNARE protein complexes.

Four-color single molecule fluorescence with noncovalent dye labeling to monitor dynamic multimolecular complexes

PubMed Central

DeRocco, Vanessa C.; Anderson, Trevor; Piehler, Jacob; Erie, Dorothy A.; Weninger, Keith

2010-01-01

To allow studies of conformational changes within multi-molecular complexes, we present a simultaneous, 4-color single molecule fluorescence methodology implemented with total internal reflection illumination and camera based, wide-field detection. We further demonstrate labeling histidine-tagged proteins non-covalently with tris-Nitrilotriacetic acid (tris-NTA) conjugated dyes to achieve single molecule detection. We combine these methods to co-localize the mismatch repair protein MutSα on DNA while monitoring MutSα-induced DNA bending using Förster resonance energy transfer (FRET) and to monitor assembly of membrane-tethered SNARE protein complexes. PMID:21091445

Surgical treatment for hypopharyngeal cysts with a side-opened direct laryngoscope.

PubMed

Kawaida, M; Fukuda, H; Shiotani, A; Kohno, N

1994-01-01

Two cases of hypopharyngeal cyst are reported. Both cysts occurred in the piriform sinus of the hypopharynx. Histopathological examination indicated that both were retention cysts. These cysts were removed by laryngomicrosurgical technique using a side-opened direct laryngoscope. In the cyst with a distinct base, a laryngomicrosurgical snare was used for removal. In the wide-based cyst, the mucous membrane around the cyst was incised with an electrosurgical instrument and then detached to facilitate removal. In this paper, we describe our surgical procedure for removing hypopharyngeal cysts and discuss the causes of such cysts.

Endovascular Retrieval of Entrapped Elephant Trunk Graft During Complex Hybrid Aortic Arch Repair

DOE Office of Scientific and Technical Information (OSTI.GOV)

Damodharan, Karthikeyan, E-mail: drdkarthik@hotmail.com; Chao, Victor T. T., E-mail: victor.chao.t.t@singhealth.com.sg; Tay, Kiang Hiong, E-mail: tay.kiang.hiong@singhealth.com.sg

Entrapment of the elephant trunk graft within the false lumen is a rare complication of surgical repair of an aortic dissection. This is normally retrieved by emergent open surgery. We describe a technique of endovascular retrieval of the dislodged graft, during hybrid aortic arch repair. The elephant trunk was cannulated through and through from a femoral access and the free end of the wire was snared and retrieved from a brachial access. The wire was externalised from both accesses and was used to reposition the graft into the true lumen using a body flossing technique.

SNARE-mediated membrane fusion in autophagy

PubMed Central

Wang, Yongyao; Li, Linsen; Hou, Chen; Lai, Ying; Long, Jiangang; Liu, Jiankang; Zhong, Qing; Diao, Jiajie

2016-01-01

Autophagy, a conserved self-eating process for the bulk degradation of cytoplasmic materials, involves double-membrane autophagosomes formed when an isolation membrane emerges and their direct fusion with lysosomes for degradation. For the early biogenesis of autophagosomes and their later degradation in lysosomes, membrane fusion is necessary, although different sets of genes and autophagy-related proteins involved in distinct fusion steps have been reported. To clarify the molecular mechanism of membrane fusion in autophagy, to not only expand current knowledge of autophagy, but also benefit human health, this review discusses key findings that elucidate the unique membrane dynamics of autophagy. PMID:27422330

Bronchoscopic resection of a tracheobronchial leiomyoma in a pregnant patient.

PubMed

Falce, K; Guy, E; Hyman, D; Hotze, T; Lazarus, D; Bandi, V; Parchem, J; Davidson, C; Munnur, U

2018-04-10

Flexible bronchoscopy, therapeutic bronchoscopy and other procedures requiring anesthesia are generally avoided in pregnancy and postponed until after delivery if possible. We report a case of a parturient with an abnormal chest radiograph and mild obstructive symptoms of unknown etiology. At bronchoscopy, a tumor associated with post-obstructive suppuration was found and excised using electrocautery snare and cryotherapy, for restoration of airway patency. Coordination between pulmonary, obstetric, anesthesia, neonatology and thoracic surgery services was essential in ensuring success and the safety of the mother and fetus. Copyright © 2018 Elsevier Ltd. All rights reserved.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007137 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

Acaba on S1 Truss during STS-119 Extravehicular Activity (EVA) 3

NASA Image and Video Library

2009-03-23

ISS018-E-042538 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007154 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007165 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

Acaba during STS-119 Extravehicular Activity (EVA) 3

NASA Image and Video Library

2009-03-23

ISS018-E-042502 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007123 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007128 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007129 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

STS-119 Extravehicular Activity (EVA) 3 Clean-Up OPS

NASA Image and Video Library

2009-03-23

S119-E-007134 (23 March 2009) --- Astronaut Joseph Acaba, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Acaba and Richard Arnold (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

Arnold on S1 Truss during STS-119 Extravehicular Activity (EVA) 3

NASA Image and Video Library

2009-03-23

ISS018-E-042546 (23 March 2009) --- Astronaut Richard Arnold, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Arnold and Joseph Acaba (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.

Device-less patent foramen ovale closure by radiofrequency thermal energy.

PubMed

Walpoth, Nazan B; Habermacher, Kathrin; Moarof, Igal; Watson, Sandy; Wahl, Andreas; Windecker, Stephan; Schönenberger, Christa; Meier, Bernhard

2008-02-23

The goal of this study was to assess the feasibility, safety and success of a system which uses radiofrequency energy (RFE) rather than a device for percutaneous closure of patent foramen ovale (PFO). Sixteen patients (10 men, 6 women, mean age 50 years) were included in the study. All of them had a proven PFO with documented right-to-left shunt (RLS) after Valsalva manoeuvre (VM) during transoesophageal echocardiography (TEE). The patients had an average PFO diameter of 6 +/- 2 mm at TEE and an average of 23 +/- 4 microembolic signals (MES) in power M-mode transcranial Doppler sonography (pm-TCD), measured over the middle cerebral artery. An atrial septal aneurysm (ASA) was present in 7 patients (44%). Balloon measurement, performed in all patients, revealed a stretched PFO diameter of 8 +/- 3 mm. In 2 patients (stretched diameter 11 and 14 mm respectively, both with ASA >10 mm), radiofrequency was not applied (PFO too large) and the PFO was closed with an Amplatzer PFO occluder instead. A 6-month follow-up TEE was performed in all patients. There were no serious adverse events during the procedure or at follow-up (12 months average). TEE 6 months after the first RFE procedure showed complete closure of the PFO in 50% of the patients (7/14). Closure appeared to be influenced by PFO diameter, complete closure being achieved in 89% (7/8) with a balloon-stretched diameter < or =7 mm but in none of the patients >7 mm. Only one of the complete closure patients had an ASA. Of the remainder, 4 (29%) had an ASA. Although the PFO was not completely closed in this group, some reduction in the diameter of the PFO and in MES was documented by TEE and pm-TCD with VM. Five of the 7 residual shunt patients received an Amplatzer PFO occluder. Except for one patient with a minimal residual shunt, all showed complete closure of PFO at 6-month follow-up TEE and pm-TCD with VM. The other two refused a closure device. The results confirm that radiofrequency closure of the PFO is safe albeit less efficacious and more complex than device closure. The technique in its current state should not be attempted in patients with a balloon-stretched PFO diameter >7 mm and an ASA.

Embolization of the Gastroduodenal Artery Before Selective Internal Radiotherapy: A Prospectively Randomized Trial Comparing Platinum-Fibered Microcoils with the Amplatzer Vascular Plug II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pech, Maciej, E-mail: maciej.pech@med.ovgu.de; Kraetsch, Annett; Wieners, Gero

2009-05-15

The Amplatzer Vascular Plug II (AVP II) is a novel device for transcatheter vessel occlusion, for which only limited comparative data exist. Embolotherapy of the gastroduodenal artery (GDA) is essential before internal radiotherapy (SIRT) in order to prevent radiation-induced peptic ulcerations due to migration of yttrium-90 microspheres. The purpose of this study was to compare the vascular anatomical limitations, procedure time, effectiveness, and safety of embolization of the GDA with coils versus the AVP II. Fifty patients stratified for SIRT were prospectively randomized for embolization of the GDA with either coils or the AVP II. The angle between the aortamore » and the celiac trunk, diameter of the GDA, fluoroscopy time and total time for embolization, number of embolization devices, complications, and durability of vessel occlusion at follow-up angiography for SIRT were recorded. A t-test was used for statistical analysis. Embolizations with either coils or the AVP II were technically feasible in all but two patients scheduled for embolization of the GDA with the AVP II. In both cases the plug could not be positioned due to the small celiac trunk outlet angles of 17{sup o} and 21{sup o}. The mean diameter of the GDA was 3.7 mm (range, 2.2-4.8 mm) for both groups. The procedures differed significantly in fluoroscopy time (7.8 min for coils vs. 2.6 min for the AVP II; P < 0.001) and embolization time (23.1 min for coils vs. 8.8 min for the AVP II; P < 0.001). A mean of 6.0 {+-} 3.2 coils were used for GDA embolization, while no more than one AVP II was needed for successful vessel occlusion (P < 0.001). One coil migration occurred during coil embolization, whereas no procedural complication was encountered with the use of the AVP II. Vessel reperfusion was noted in only one patient, in whom coil embolization was performed. In conclusion, embolization of the GDA with the AVP II is safe, easy, rapid, and highly effective; only an extremely sharp-angled celiac trunk outlet represented an anatomical limitation for device deployment.« less

Comparative testing of reliability and audit utility of ordinal objective calculus complexity scores. Can we make an informed choice yet?

PubMed

Jaipuria, Jiten; Suryavanshi, Manav; Sen, Tridib K

2016-12-01

To assess the reliability of the Guy's Stone Score, the Seoul National University Renal Stone Complexity (S-ReSC) score and the S.T.O.N.E. scores in percutaneous nephrolithotomy (PCNL), and assess their utility in discriminating outcomes [stone free rate (SFR), complications, need for multiple PCNL sessions, and auxiliary procedures] valid across parameters of experience of surgeon, independence from surgical approach, and variations in institution-specific instrumentation. A prospectively maintained database of two tertiary institutions was analysed (606 cases). Institutes differed in instrumentation, while the overall surgical team comprised: two trainees (experience <100 cases), two junior consultants (experience 100-200 cases), and two senior surgeons (experience >1000 cases). Scores were assigned and re-assigned after 4 months by one trainee and an expert surgeon. Inter-rater and test-retest agreement were analysed by Cohen's κ and intraclass correlation coefficient. Multivariate logistic regression models were created adjusting outcomes for the institution, comorbidity, Amplatz size, access tract location, the number of punctures, the experience level of the surgeon, and individual scoring system, and receiver operating curves were analysed for comparison. Despite some areas of inconsistencies, individually all scores had excellent inter-rater and test-retest concordance. On multivariable analyses, while the experience of the surgeon and surgical approach characteristics (such as access tract location, Amplatz size, and number of punctures) remained independently associated with different outcomes in varying combinations, calculus complexity scores were found consistently to be independently associated with all outcomes. The S-ReSC score had a superior association with SFR, the need for multiple PCNL sessions, and auxiliary procedures. Individually all scoring systems performed well. On cross comparison, the S-ReSC score consistently emerged to be more superiorly associated with all outcomes, signifying the importance of the distributional complexity of the calculus (which also indirectly amalgamates the influence of stone number, size, and anatomical location) in discriminating outcomes. Our study proves the utility of scoring systems in prognosticating multiple outcomes and also clarifies important aspects of their practical application including future roles such as benchmarking, audit, training, and objective assessment of surgical technique modifications. © 2016 The Authors BJU International © 2016 BJU International Published by John Wiley & Sons Ltd.

Comparison of cost-effectiveness and postoperative outcome of device closure and open surgery closure techniques for treatment of patent ductus arteriosus.

PubMed

Ahmadi, Alireza; Sabri, Mohammadreza; Bigdelian, Hamid; Dehghan, Bahar; Gharipour, Mojgan

2014-01-01

Various devices have been recently employed for percutaneous closure of the patent ductus arteriosus (PDA). Although the high effectiveness of device closure techniques has been clearly determined, a few studies have focused on the cost-effectiveness and also postoperative complications of these procedures in comparison with open surgery. The present study aimed to evaluate the clinical outcome and cost-effectiveness of PDA occlusion by Amplatzer and coil device in comparisong with open surgery. In this cross-sectional study, a randomized sample of 201 patients aged 1 month to 16 years (105 patients with device closure and 96 patients with surgical closure) was selected. The ratio of total pulmonary blood flow to total systemic blood flow, the Qp/Qs ratio, was measured using a pulmonary artery catheter. The cost analysis included direct medical care costs associated with device implantation and open surgery, as well as professional fees. All costs were calculated in Iranian Rials and then converted to US dollars. There was no statistical difference in mean Qp/Qs ratio before the procedure between the device closure group and the open surgery group (2.1 ± 0.7 versus 1.7 ± 0.6, P = 0.090). The mean measured costs were overall higher in the device closure group than in open closure group (948.87 ± 548.76 US$ versus 743.70 ± 696.91 US$, P < 0.001). This difference remained significant after adjustment for age and gender (Standardized Beta = 0.160, P = 0.031). PDA closure with the Amplatzer ductal occluder (1053.05 ± 525.73 US$) or with Nit-Occlud coils (PFM) (912.73 ± 565.94 US$, P < 0.001) was more expensive than that via open surgery. However, the Cook detachable spring coils device closure (605.65 ± 194.62 US$, P = 0.650) had a non-significant cost difference with open surgery. No event was observed in the device closure group regarding in-hospital mortality or morbidity; however, in another group, 2 in-hospital deaths occurred, two patients experienced pneumonia and seizure, and one suffered electrolyte abnormalities including hyponatremia and hypocalcemia. Although open surgery seems to be less expensive than device closure technique, because of lower mortality and morbidity, the latter group is more preferable.

Components of the SNARE-containing regulon are co-regulated in root cells undergoing defense

PubMed Central

Klink, Vincent P.; Sharma, Keshav; Pant, Shankar R.; McNeece, Brant; Niraula, Prakash; Lawrence, Gary W.

2017-01-01

ABSTRACT The term regulon has been coined in the genetic model plant Arabidopsis thaliana, denoting a structural and physiological defense apparatus defined genetically through the identification of the penetration (pen) mutants. The regulon is composed partially by the soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) syntaxin PEN1. PEN1 has homology to a Saccharomyces cerevisae gene that regulates a Secretion (Sec) protein, Suppressor of Sec 1 (Sso1p). The regulon is also composed of the β-glucosidase (PEN2) and an ATP binding cassette (ABC) transporter (PEN3). While important in inhibiting pathogen infection, limited observations have been made regarding the transcriptional regulation of regulon genes until now. Experiments made using the model agricultural Glycine max (soybean) have identified co-regulated gene expression of regulon components. The results explain the observation of hundreds of genes expressed specifically in the root cells undergoing the natural process of defense. Data regarding additional G. max genes functioning within the context of the regulon are presented here, including Sec 14, Sec 4 and Sec 23. Other examined G. max homologs of membrane fusion genes include an endosomal bromo domain-containing protein1 (Bro1), syntaxin6 (SYP6), SYP131, SYP71, SYP8, Bet1, coatomer epsilon (ε-COP), a coatomer zeta (ζ-COP) paralog and an ER to Golgi component (ERGIC) protein. Furthermore, the effectiveness of biochemical pathways that would function within the context of the regulon ave been examined, including xyloglucan xylosyltransferase (XXT), reticuline oxidase (RO) and galactinol synthase (GS). The experiments have unveiled the importance of the regulon during defense in the root and show how the deposition of callose relates to the process. PMID:28010187

Interactions of a potent cyclic peptide inhibitor with the light chain of botulinum neurotoxin A: Insights from X-ray crystallography.

PubMed

Kumaran, Desigan; Adler, Michael; Levit, Matthew; Krebs, Michael; Sweeney, Richard; Swaminathan, Subramanyam

2015-11-15

The seven antigenically distinct serotypes (A-G) of botulinum neurotoxin (BoNT) are responsible for the deadly disease botulism. BoNT serotype A (BoNT/A) exerts its lethal action by cleaving the SNARE protein SNAP-25, leading to inhibition of neurotransmitter release, flaccid paralysis and autonomic dysfunction. BoNTs are dichain proteins consisting of a ∼ 100 kDa heavy chain and a ∼ 50 kDa light chain; the former is responsible for neurospecific binding, internalization and translocation, and the latter for cleavage of neuronal SNARE proteins. Because of their extreme toxicity and history of weaponization, the BoNTs are regarded as potential biowarfare/bioterrorism agents. No post-symptomatic therapeutic interventions are available for BoNT intoxication other than intensive care; therefore it is imperative to develop specific antidotes against this neurotoxin. To this end, a cyclic peptide inhibitor (CPI-1) was evaluated in a FRET assay for its ability to inhibit BoNT/A light chain (Balc). CPI was found to be highly potent, exhibiting a Ki of 12.3 nM with full-length Balc448 and 39.2 nM using a truncated crystallizable form of the light chain (Balc424). Cocrystallization studies revealed that in the Balc424-CPI-1 complex, the inhibitor adopts a helical conformation, occupies a high percentage of the active site cavity and interacts in an amphipathic manner with critical active site residues. The data suggest that CPI-1 prevents SNAP-25 from accessing the Balc active site by blocking both the substrate binding path at the surface and the Zn(2+) binding region involved in catalysis. This differs from linear peptide inhibitors described to date which block only the latter. Published by Elsevier Ltd.

Synaptotagmin-7 Functions to Replenish Insulin Granules for Exocytosis in Human Islet β-Cells.

PubMed

Dolai, Subhankar; Xie, Li; Zhu, Dan; Liang, Tao; Qin, Tairan; Xie, Huanli; Kang, Youhou; Chapman, Edwin R; Gaisano, Herbert Y

2016-07-01

Synaptotagmin (Syt)-7, a major component of the exocytotic machinery in neurons, is also the major Syt in rodent pancreatic β-cells shown to mediate glucose-stimulated insulin secretion (GSIS). However, Syt-7's precise exocytotic actions in β-cells remain unknown. We show that Syt-7 is abundant in human β-cells. Adenovirus-short hairpin RNA knockdown (KD) of Syt-7 in human islets reduced first- and second-phase GSIS attributed to the reduction of exocytosis of predocked and newcomer insulin secretory granules (SGs). Glucose stimulation expectedly induced Syt-7 association in a Ca(2+)-dependent manner with syntaxin-3 and syntaxin-1A soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes known to mediate exocytosis of newcomer and predocked SGs, respectively. However, Syt-7-KD did not disrupt SNARE complex assembly. Instead, electron microscopy analysis showed that Syt-7-KD reduced the recruitment of SGs to the plasma membrane after glucose-stimulated depletion, which could not be rescued by glucagon-like peptide 1 pretreatment. To assess the possibility that this new action of Syt-7 on SG recruitment may involve calmodulin (CaM), pretreatment of islets with CaM blocker calmidazolium showed effects very similar to those of Syt-7-KD. Syt-7 therefore plays a novel more dominant function in the replenishment of releasable SG pools in human β-cells than its previously purported role in exocytotic fusion per se. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Choroid plexus epithelial cells express the adhesion protein P-cadherin at cell-cell contacts and syntaxin-4 in the luminal membrane domain.

PubMed

Christensen, Inga Baasch; Mogensen, Esben Nees; Damkier, Helle Hasager; Praetorius, Jeppe

2018-05-01

The choroid plexus epithelial cells (CPECs) belong to a small group of polarized cells, where the Na + -K + -ATPase is expressed in the luminal membrane. The basic polarity of the cells is, therefore, still debated. We investigated the subcellular distribution of an array of proteins known to play fundamental roles either in establishing and maintaining basic cell polarity or in the polarized delivery and recycling of plasma membrane proteins. Immunofluorescence histochemical analysis was applied to determine the subcellular localization of apical and basolateral membrane determinants. Mass spectrometry analysis of CPECs isolated by fluorescence-activated cell sorting was applied to determine the expression of specific forms of the proteins. CPECs mainly express the cell-adhesive P-cadherin, which is localized to the lateral membranes. Proteins belonging to the Crumbs and partitioning defective (Par) protein complexes were all localized to the luminal membrane domain. Par-1 and the Scribble complex were localized to the basolateral membrane domain. Lethal(2) giant larvae homolog 2 (Lgl2) labeling was preferentially observed in the luminal membrane domain. Phosphatidylinositol 3,4,5-trisphosphate (PIP 3 ) was immunolocalized to the basolateral membrane domain, while phosphatidylinositol 4,5-bisphosphate (PIP 2 ) staining was most prominent in the luminal membrane domain along with the PIP 3 phosphatase, Pten. The apical target-SNARE syntaxin-3 and the basolateral target-SNARE syntaxin-4 were both localized to the apical membrane domain in CPECs, which lack cellular expression of the clathrin adaptor protein AP-1B for basolateral protein recycling. In conclusion, the CPECs are conventionally polarized, but express P-cadherin at cell-cell contacts, and Lgl2 and syntaxin-4 in the luminal plasma membrane domain.

Equatorin is not essential for acrosome biogenesis but is required for the acrosome reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Jianxiu; Graduate School of the Chinese Academy of Sciences, Beijing 100049; Chen, Min

Highlights: • Eqtn knockout mice were used for these experiments. • In vivo and in vitro fertilization analyses were performed. • Eqtn-deficient sperm were evaluated by transmission electron microscopy (TEM) and an A23187-induced acrosome reaction (AR) assay. • Co-immunoprecipitation (Co-IP) was performed to assess the interaction between Eqtn and the SNARE complex. - Abstract: The acrosome is a specialized organelle that covers the anterior part of the sperm nucleus and plays an essential role in mammalian fertilization. However, the regulatory mechanisms controlling acrosome biogenesis and acrosome exocytosis during fertilization are largely unknown. Equatorin (Eqtn) is a membrane protein that ismore » specifically localized to the acrosomal membrane. In the present study, the physiological functions of Eqtn were investigated using a gene knockout mouse model. We found that Eqtn{sup −/−} males were subfertile. Only approximately 50% of plugged females were pregnant after mating with Eqtn{sup −/−} males, whereas more than 90% of plugged females were pregnant after mating with control males. Sperm and acrosomes from Eqtn{sup −/−} mice presented normal motility and morphology. However, the fertilization and induced acrosome exocytosis rates of Eqtn-deficient sperm were dramatically reduced. Further studies revealed that the Eqtn protein might interact with Syntaxin1a and SNAP25, but loss of Eqtn did not affect the protein levels of these genes. Therefore, our study demonstrates that Eqtn is not essential for acrosome biogenesis but is required for the acrosome reaction. Eqtn is involved in the fusion of the outer acrosomal membrane and the sperm plasma membrane during the acrosome reaction, most likely via an interaction with the SNARE complex.« less

Impaired adrenal medullary function in a mouse model of depression induced by unpredictable chronic stress.

PubMed

Santana, Magda M; Rosmaninho-Salgado, Joana; Cortez, Vera; Pereira, Frederico C; Kaster, Manuella P; Aveleira, Célia A; Ferreira, Marisa; Álvaro, Ana Rita; Cavadas, Cláudia

2015-10-01

Stress has been considered determinant in the etiology of depression. The adrenal medulla plays a key role in response to stress by releasing catecholamines, which are important to maintain homeostasis. We aimed to study the adrenal medulla in a mouse model of depression induced by 21 days of unpredictable chronic stress (UCS). We observed that UCS induced a differential and time-dependent change in adrenal medulla. After 7 days of UCS, mice did not show depressive-like behavior, but the adrenal medullae show increased protein and/or mRNA levels of catecholamine biosynthetic enzymes (TH, DβH and PNMT), Neuropeptide Y, the SNARE protein SNAP-25, the catecholamine transporter VMAT2 and the chromaffin progenitor cell markers, Mash1 and Phox2b. Moreover, 7 days of UCS induced a decrease in the chromaffin progenitor cell markers, Sox9 and Notch1. This suggests an increased capacity of chromaffin cells to synthesize, store and release catecholamines. In agreement, after 7 days, UCS mice had higher NE and EP levels in adrenal medulla. Opposite, when mice were submitted to 21 days of UCS, and showed a depressive like behavior, adrenal medullae had lower protein and/or mRNA levels of catecholamine biosynthetic enzymes (TH, DβH, PNMT), catecholamine transporters (NET, VMAT1), SNARE proteins (synthaxin1A, SNAP25, VAMP2), catecholamine content (EP, NE), and lower EP serum levels, indicating a reduction in catecholamine synthesis, re-uptake, storage and release. In conclusion, this study suggests that mice exposed to UCS for a period of 21 days develop a depressive-like behavior accompanied by an impairment of adrenal medullary function. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Management of Fractured Inferior Vena Cava Filters: Outcomes by Fragment Location.

PubMed

Trerotola, Scott O; Stavropoulos, S William

2017-09-01

Purpose To inform the management of fractured inferior vena cava filters on the basis of results from a tertiary referral center specializing in complex filter retrieval. Materials and Methods This study had institutional review board approval and was HIPAA compliant. Retrospective analysis of all patients with fractured filters and/or filter fragments evaluated for removal in a complex filter removal program was performed. Removal was attempted when fragments were intravascular or immediately extravascular by using primarily endobronchial forceps for caval fragments and snares for cardiac and pulmonary fragments. Data collected included success rate and complications of filter and fragment removal, symptoms relating to the filter or fragment, techniques used for removal, and follow-up of retained fragments. Results Sixty-five patients (12 men, 53 women) of a total of 222 patients referred for complex retrieval had fractured filters. Of these patients, two had undergone filter removal elsewhere and had retained fragments. All 63 filters were removed successfully with forceps (n = 61), a cone (n = 1), or a snare (n = 1). There were 116 separate filter fragments; removal was attempted for 78 fragments. Removal was successful for 63 (81%) of 78 fragments and varied by location. All extravascular fragments except one were retained. In all, 63 (54%) of 116 fragments were removed percutaneously, rendering 34 (54%) of 63 patients fragment free. Five minor (7.7% [five of 65]) and four major (6.2% [four of 65]) complications occurred. Conclusion Intravascular filter fragments can be removed safely with success rates that vary according to location. Because extravascular fragments are not readily accessible for removal, many patients are not rendered fragment free. © RSNA, 2017 Online supplemental material is available for this article.

Extended cold snare polypectomy for small colorectal polyps increases the R0 resection rate.

PubMed

Abe, Yasuhiro; Nabeta, Haruaki; Koyanagi, Ryota; Nakamichi, Taro; Hirashima, Hayato; Lefor, Alan Kawarai; Shinozaki, Satoshi

2018-02-01

 Despite widespread use of cold snare polypectomy (CSP), the R0 resection rate is not well documented. We perform extended CSP, resecting polyps with a > 1 mm circumferential margin. The aim of this study is to compare the R0 resection rate of extended CSP with conventional CSP and to assess safety. From April 2014 to September 2016, 712 non-pedunculated colorectal polyps, < 10 mm in size, resected using CSP from 316 patients were retrospectively analyzed.  We divided lesions into conventional CSP (n = 263) and extended CSP groups (n = 449). The baseline characteristics of these two groups were not significantly different in univariate or multivariate analyses. Sessile polyps comprised 94 % (668/712), and the remaining were flat-elevated polyps. Mean size of polyps (±standard deviation) was 4.2 ± 1.5 mm. The most frequent pathology was low grade adenoma (97 %, 689/712). The R0 resection rate was significantly higher in the extended CSP group (439/449 [98 %]) than in the conventional CSP group (222/263 [84 %], P  < 0.001). There was no delayed bleeding or perforation in either group (conventional CSP group, 0/263, 95 % confidence interval: 0.0 - 1.4 % and extended CSP group, 0/449, 95 % confidence interval: 0.0 - 0.8 %).  Extended CSP results in a higher R0 resection rate compared with conventional CSP. Extended CSP did not result in a higher rate of delayed bleeding or perforation. Extended CSP is a safe and promising procedure for endoscopic resection of non-pedunculated colorectal polyps < 10 mm in size.

Removal of diminutive colorectal polyps: A prospective randomized clinical trial between cold snare polypectomy and hot forceps biopsy

PubMed Central

Komeda, Yoriaki; Kashida, Hiroshi; Sakurai, Toshiharu; Tribonias, George; Okamoto, Kazuki; Kono, Masashi; Yamada, Mitsunari; Adachi, Teppei; Mine, Hiromasa; Nagai, Tomoyuki; Asakuma, Yutaka; Hagiwara, Satoru; Matsui, Shigenaga; Watanabe, Tomohiro; Kitano, Masayuki; Chikugo, Takaaki; Chiba, Yasutaka; Kudo, Masatoshi

2017-01-01

AIM To compare the efficacy and safety of cold snare polypectomy (CSP) and hot forceps biopsy (HFB) for diminutive colorectal polyps. METHODS This prospective, randomized single-center clinical trial included consecutive patients ≥ 20 years of age with diminutive colorectal polyps 3-5 mm from December 2014 to October 2015. The primary outcome measures were en-bloc resection (endoscopic evaluation) and complete resection rates (pathological evaluation). The secondary outcome measures were the immediate bleeding or immediate perforation rate after polypectomy, delayed bleeding or delayed perforation rate after polypectomy, use of clipping for bleeding or perforation, and polyp retrieval rate. Prophylactic clipping after polyp removal wasn’t routinely performed. RESULTS Two hundred eight patients were randomized into the CSP (102), HFB (106) and 283 polyps were evaluated (CSP: 148, HFB: 135). The en-bloc resection rate was significantly higher with CSP than with HFB [99.3% (147/148) vs 80.0% (108/135), P < 0.0001]. The complete resection rate was significantly higher with CSP than with HFB [80.4% (119/148) vs 47.4% (64/135), P < 0.0001]. The immediate bleeding rate was similar between the groups [8.6% (13/148) vs 8.1% (11/135), P = 1.000], and endoscopic hemostasis with hemoclips was successful in all cases. No cases of perforation or delayed bleeding occurred. The rate of severe tissue injury to the pathological specimen was higher HFB than CSP [52.6% (71/135) vs 1.3% (2/148), P < 0.0001]. Polyp retrieval failure was encountered CSP (7), HFB (2). CONCLUSION CSP is more effective than HFB for resecting diminutive polyps. Further long-term follow-up study is required. PMID:28127206

Removal of diminutive colorectal polyps: A prospective randomized clinical trial between cold snare polypectomy and hot forceps biopsy.

PubMed

Komeda, Yoriaki; Kashida, Hiroshi; Sakurai, Toshiharu; Tribonias, George; Okamoto, Kazuki; Kono, Masashi; Yamada, Mitsunari; Adachi, Teppei; Mine, Hiromasa; Nagai, Tomoyuki; Asakuma, Yutaka; Hagiwara, Satoru; Matsui, Shigenaga; Watanabe, Tomohiro; Kitano, Masayuki; Chikugo, Takaaki; Chiba, Yasutaka; Kudo, Masatoshi

2017-01-14

To compare the efficacy and safety of cold snare polypectomy (CSP) and hot forceps biopsy (HFB) for diminutive colorectal polyps. This prospective, randomized single-center clinical trial included consecutive patients ≥ 20 years of age with diminutive colorectal polyps 3-5 mm from December 2014 to October 2015. The primary outcome measures were en-bloc resection (endoscopic evaluation) and complete resection rates (pathological evaluation). The secondary outcome measures were the immediate bleeding or immediate perforation rate after polypectomy, delayed bleeding or delayed perforation rate after polypectomy, use of clipping for bleeding or perforation, and polyp retrieval rate. Prophylactic clipping after polyp removal wasn't routinely performed. Two hundred eight patients were randomized into the CSP (102), HFB (106) and 283 polyps were evaluated (CSP: 148, HFB: 135). The en-bloc resection rate was significantly higher with CSP than with HFB [99.3% (147/148) vs 80.0% (108/135), P < 0.0001]. The complete resection rate was significantly higher with CSP than with HFB [80.4% (119/148) vs 47.4% (64/135), P < 0.0001]. The immediate bleeding rate was similar between the groups [8.6% (13/148) vs 8.1% (11/135), P = 1.000], and endoscopic hemostasis with hemoclips was successful in all cases. No cases of perforation or delayed bleeding occurred. The rate of severe tissue injury to the pathological specimen was higher HFB than CSP [52.6% (71/135) vs 1.3% (2/148), P < 0.0001]. Polyp retrieval failure was encountered CSP (7), HFB (2). CSP is more effective than HFB for resecting diminutive polyps. Further long-term follow-up study is required.

Golgi-to-Endoplasmic Reticulum (ER) Retrograde Traffic in Yeast Requires Dsl1p, a Component of the ER Target Site that Interacts with a COPI Coat Subunit

PubMed Central

Reilly, Barbara A.; Kraynack, Bryan A.; VanRheenen, Susan M.; Waters, M. Gerard

2001-01-01

DSL1 was identified through its genetic interaction with SLY1, which encodes a t-SNARE-interacting protein that functions in endoplasmic reticulum (ER)-to-Golgi traffic. Conditional dsl1 mutants exhibit a block in ER-to-Golgi traffic at the restrictive temperature. Here, we show that dsl1 mutants are defective for retrograde Golgi-to-ER traffic, even under conditions where no anterograde transport block is evident. These results suggest that the primary function of Dsl1p may be in retrograde traffic, and that retrograde defects can lead to secondary defects in anterograde traffic. Dsl1p is an ER-localized peripheral membrane protein that can be extracted from the membrane in a multiprotein complex. Immunoisolation of the complex yielded Dsl1p and proteins of ∼80 and ∼55 kDa. The ∼80-kDa protein has been identified as Tip20p, a protein that others have shown to exist in a tight complex with Sec20p, which is ∼50 kDa. Both Sec20p and Tip20p function in retrograde Golgi-to-ER traffic, are ER-localized, and bind to the ER t-SNARE Ufe1p. These findings suggest that an ER-localized complex of Dsl1p, Sec20p, and Tip20p functions in retrograde traffic, perhaps upstream of a Sly1p/Ufe1p complex. Last, we show that Dsl1p interacts with the δ-subunit of the retrograde COPI coat, Ret2p, and discuss possible roles for this interaction. PMID:11739780

Cyclin-dependent kinase 5 regulates degranulation in human eosinophils.

PubMed

Odemuyiwa, Solomon O; Ilarraza, Ramses; Davoine, Francis; Logan, Michael R; Shayeganpour, Anooshirvan; Wu, Yingqi; Majaesic, Carina; Adamko, Darryl J; Moqbel, Redwan; Lacy, Paige

2015-04-01

Degranulation from eosinophils in response to secretagogue stimulation is a regulated process that involves exocytosis of granule proteins through specific signalling pathways. One potential pathway is dependent on cyclin-dependent kinase 5 (Cdk5) and its effector molecules, p35 and p39, which play a central role in neuronal cell exocytosis by phosphorylating Munc18, a regulator of SNARE binding. Emerging evidence suggests a role for Cdk5 in exocytosis in immune cells, although its role in eosinophils is not known. We sought to examine the expression of Cdk5 and its activators in human eosinophils, and to assess the role of Cdk5 in eosinophil degranulation. We used freshly isolated human eosinophils and analysed the expression of Cdk5, p35, p39 and Munc18c by Western blot, RT-PCR, flow cytometry and immunoprecipitation. Cdk5 kinase activity was determined following eosinophil activation. Cdk5 inhibitors were used (roscovitine, AT7519 and small interfering RNA) to determine its role in eosinophil peroxidase (EPX) secretion. Cdk5 was expressed in association with Munc18c, p35 and p39, and phosphorylated following human eosinophil activation with eotaxin/CCL11, platelet-activating factor, and secretory IgA-Sepharose. Cdk5 inhibitors (roscovitine, AT7519) reduced EPX release when cells were stimulated by PMA or secretory IgA. In assays using small interfering RNA knock-down of Cdk5 expression in human eosinophils, we observed inhibition of EPX release. Our findings suggest that in activated eosinophils, Cdk5 is phosphorylated and binds to Munc18c, resulting in Munc18c release from syntaxin-4, allowing SNARE binding and vesicle fusion, with subsequent eosinophil degranulation. Our work identifies a novel role for Cdk5 in eosinophil mediator release by agonist-induced degranulation. © 2014 John Wiley & Sons Ltd.

Disease resistance through impairment of α-SNAP–NSF interaction and vesicular trafficking by soybean Rhg1

PubMed Central

Bayless, Adam M.; Smith, John M.; Song, Junqi; McMinn, Patrick H.; Teillet, Alice; August, Benjamin K.

2016-01-01

α-SNAP [soluble NSF (N-ethylmaleimide–sensitive factor) attachment protein] and NSF proteins are conserved across eukaryotes and sustain cellular vesicle trafficking by mediating disassembly and reuse of SNARE protein complexes, which facilitate fusion of vesicles to target membranes. However, certain haplotypes of the Rhg1 (resistance to Heterodera glycines 1) locus of soybean possess multiple repeat copies of an α-SNAP gene (Glyma.18G022500) that encodes atypical amino acids at a highly conserved functional site. These Rhg1 loci mediate resistance to soybean cyst nematode (SCN; H. glycines), the most economically damaging pathogen of soybeans worldwide. Rhg1 is widely used in agriculture, but the mechanisms of Rhg1 disease resistance have remained unclear. In the present study, we found that the resistance-type Rhg1 α-SNAP is defective in interaction with NSF. Elevated in planta expression of resistance-type Rhg1 α-SNAPs depleted the abundance of SNARE-recycling 20S complexes, disrupted vesicle trafficking, induced elevated abundance of NSF, and caused cytotoxicity. Soybean, due to ancient genome duplication events, carries other loci that encode canonical (wild-type) α-SNAPs. Expression of these α-SNAPs counteracted the cytotoxicity of resistance-type Rhg1 α-SNAPs. For successful growth and reproduction, SCN dramatically reprograms a set of plant root cells and must sustain this sedentary feeding site for 2–4 weeks. Immunoblots and electron microscopy immunolocalization revealed that resistance-type α-SNAPs specifically hyperaccumulate relative to wild-type α-SNAPs at the nematode feeding site, promoting the demise of this biotrophic interface. The paradigm of disease resistance through a dysfunctional variant of an essential gene may be applicable to other plant–pathogen interactions. PMID:27821740

Nuclear Expression of GS28 Protein: A Novel Biomarker that Predicts Prognosis in Colorectal Cancers

PubMed Central

Lee, Sung Hak; Yoo, Hyung Jae; Rim, Do Eun; Cui, Yinji; Lee, Ahwon; Jung, Eun Sun; Oh, Seung Taek; Kim, Jun Gi; Kwon, Oh-Joo; Kim, Su Young; Jeong, Seong-Whan

2017-01-01

Aims: GS28 (Golgi SNARE protein, 28 kDa), a member of the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) protein family, plays a critical role in mammalian endoplasmic reticulum (ER)-Golgi or intra-Golgi vesicle transport. To date, few researches on the GS28 protein in human cancer tissues have been reported. In this study, we assessed the prognostic value of GS28 in patients with colorectal cancer (CRC). Methods and results: We screened for GS28 expression using immunohistochemistry in 230 surgical CRC specimens. The CRCs were right-sided and left-sided in 28.3% (65/230) and 71.3% (164/230) of patients, respectively. GS28 staining results were available in 214 cases. Among these, there were 26 nuclear predominant cases and 188 non-nuclear predominant cases. Stromal GS28 expression was noted in 152 cases of CRC. GS28 nuclear predominant immunoreactivity was significantly associated with advanced tumour stage (p = 0.045) and marginally associated with perineural invasion (p = 0.064). Decreased GS28 expression in the stromal cells was significantly associated with lymph node metastasis (N stage; p = 0.036). GS28 expression was not associated with epidermal growth factor receptor (EGFR) immunohistochemical positivity or KRAS mutation status. Investigation of the prognostic value of GS28 with Kaplan-Meier analysis revealed a correlation with overall survival (p = 0.004). Cases with GS28 nuclear predominant expression had significantly poorer overall survival than those with a non-nuclear predominant pattern. Conclusions: Taken together, these results indicate that GS28 nuclear predominant expression could serve as a prognostic marker for CRC and may help in identifying aggressive forms of CRC. PMID:28638266

Should hot biopsy forceps be abandoned for polypectomy of diminutive colorectal polyps?

PubMed Central

Panteris, Vasileios; Vezakis, Antonios; Triantafillidis, JK

2018-01-01

Standardized approach to polypectomy of diminutive colorectal polyps (DCPs) is lacking since cold biopsy forceps have been associated with high levels of recurrence, hot biopsy forceps are considered inadequate and risky and cold snaring is currently under investigation for its efficacy and safety. This has led to confusion and a gap in clinical practice. This article discusses the usefulness and contemporary practical applicability of hot biopsy forceps and provides well-intentioned criticism of the new European guidelines for the treatment of DCPs. Diminutive colorectal polyps are a source of frustration for the endoscopist since their small size is accompanied by a considerable risk of premalignant neoplasia and a small but non-negligible risk of advanced neoplasia and even cancer. Since the proportion of diminutive colorectal polyps is substantial and exceeds that of larger polyps, their effective removal poses a considerable workload and a therapeutic challenge. During the last decade, the introduction of cold snaring to routine endoscopy practice has attempted to overcome the use of prior techniques, such as hot biopsy forceps. It is important to recognize that with the exception of endoscopic methods that are obviously unsafe and inadequate to serve their purpose, all other interventional endoscopic methods are operator-dependent in the sense that specific expertise and training are obligatory for the success of any therapeutic intervention. Since relevant publications on hot biopsy forceps are still in favor of its careful use, as it has not yet demonstrated inferiority compared with newer techniques, it would be prudent for any medical practitioner to evaluate the available tools and judge any new proposed technique based on the evidence before it is adopted. PMID:29662295

Vesicle-associated membrane protein 7 (VAMP-7) is essential for target cell killing in a natural killer cell line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marcet-Palacios, Marcelo; Odemuyiwa, Solomon O.; Coughlin, Jason J.

2008-02-15

Natural killer cells recognize and induce apoptosis in foreign, transformed or virus-infected cells through the release of perforin and granzymes from secretory lysosomes. Clinically, NK-cell mediated killing is a major limitation to successful allo- and xenotransplantation. The molecular mechanisms that regulate the fusion of granzyme B-containing secretory lysosomes to the plasma membrane in activated NK cells, prior to target cell killing, are not fully understood. Using the NK cell line YT-Indy as a model, we have investigated the expression of SNAP REceptors (SNAREs), both target (t-) and vesicular (v-) SNAREs, and their function in granzyme B-mediated target cell killing. Ourmore » data showed that YT-Indy cells express VAMP-7 and SNAP-23, but not VAMP-2. VAMP-7 was associated with granzyme B-containing lysosomal granules. Using VAMP-7 small interfering RNA (siRNA), we successfully knocked down the expression of VAMP-7 protein in YT-Indy to less than 10% of untreated cells in 24 h. VAMP7-deficient YT-Indy cells activated via co-culture with Jurkat cells released <1 ng/mL of granzyme B, compared to 1.5-2.5 {mu}g/mL from controls. Using Jurkat cells as targets, we showed a 7-fold reduction in NK cell-mediated killing by VAMP-7 deficient YT-Indy cells. Our results show that VAMP-7 is a crucial component of granzyme B release and target cell killing in the NK cell line YT-Indy. Thus, targeting VAMP-7 expression specifically with siRNA, following transplantation, may be a viable strategy for preventing NK cell-mediated transplant rejection, in vivo.« less

Accelerated intoxication of GABAergic synapses by botulinum neurotoxin A disinhibits stem cell-derived neuron networks prior to network silencing

PubMed Central

Beske, Phillip H.; Scheeler, Stephen M.; Adler, Michael; McNutt, Patrick M.

2015-01-01

Botulinum neurotoxins (BoNTs) are extremely potent toxins that specifically cleave SNARE proteins in peripheral synapses, preventing neurotransmitter release. Neuronal responses to BoNT intoxication are traditionally studied by quantifying SNARE protein cleavage in vitro or monitoring physiological paralysis in vivo. Consequently, the dynamic effects of intoxication on synaptic behaviors are not well-understood. We have reported that mouse embryonic stem cell-derived neurons (ESNs) are highly sensitive to BoNT based on molecular readouts of intoxication. Here we study the time-dependent changes in synapse- and network-level behaviors following addition of BoNT/A to spontaneously active networks of glutamatergic and GABAergic ESNs. Whole-cell patch-clamp recordings indicated that BoNT/A rapidly blocked synaptic neurotransmission, confirming that ESNs replicate the functional pathophysiology responsible for clinical botulism. Quantitation of spontaneous neurotransmission in pharmacologically isolated synapses revealed accelerated silencing of GABAergic synapses compared to glutamatergic synapses, which was consistent with the selective accumulation of cleaved SNAP-25 at GAD1+ pre-synaptic terminals at early timepoints. Different latencies of intoxication resulted in complex network responses to BoNT/A addition, involving rapid disinhibition of stochastic firing followed by network silencing. Synaptic activity was found to be highly sensitive to SNAP-25 cleavage, reflecting the functional consequences of the localized cleavage of the small subpopulation of SNAP-25 that is engaged in neurotransmitter release in the nerve terminal. Collectively these findings illustrate that use of synaptic function assays in networked neurons cultures offers a novel and highly sensitive approach for mechanistic studies of toxin:neuron interactions and synaptic responses to BoNT. PMID:25954159

Evaluating trapping techniques to reduce potential for injury to Mexican wolves

USGS Publications Warehouse

Turnbull, T.T.; Cain, J.W.; Roemer, G.W.

2011-01-01

Increased scrutiny of furbearer trapping has resulted in more regulation and even prohibition of common trapping methods in some States. Concerns regarding the potential negative impacts of regulated furbearer trapping on reintroduced Mexican gray wolves (Canis lupus baileyi) led now former Governor Bill Richardson to issue an executive order prohibiting trapping in the New Mexico portion of the Blue Range Wolf Recovery Area (BRWRA). This ban was to last for at least 6 months and required an evaluation of the risk posed to wolves by traps and snares legally permitted in New Mexico. We reviewed various threats to wolves in the BRWRA, including threats posed by regulated furbearer trapping. Seventy-eight Mexican wolf mortalities were documented during the reintroduction effort (1998-2010). More than 80 percent of documented mortalities were human-caused: illegal shooting (47.4 percent), vehicle collisions (15.4 percent), lethal removal by the U.S. Fish and Wildlife Service (USFWS) (14.1 percent), nonproject-related trapping (2.6 percent), project-related trapping (1.3 percent), and legal shooting by the public (1.3 percent). The remaining 17.9 percent of mortalities were a result of natural causes. An additional 23 wolves were permanently removed from the wild by USFWS. Of 13 trapping incidents in New Mexico that involved trappers other than USFWS project personnel, 7 incidents resulted in injuries to wolves, 2 wolves sustained injuries severe enough to result in leg amputations, and 2 wolves died as a result of injuries sustained. Rubber-padded foothold traps and properly set snares would most likely reduce trap-related injuries to Mexican wolves; however, impacts caused by trapping are outnumbered by other, human-caused impacts.

STS-119 Extravehicular Activity (EVA) 3 Crew and Equipment Translation Aid (CETA) Cart 2 Relocate OPS

NASA Image and Video Library

2009-03-23

S119-E-007257 (23 March 2009) --- Astronaut Richard Arnold, STS-119 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 27-minute spacewalk, Arnold and Joseph Acaba (out of frame), mission specialist, helped robotic arm operators relocate the Crew Equipment Translation Aid (CETA) cart from the Port 1 to Starboard 1 truss segment, installed a new coupler on the CETA cart, lubricated snares on the "B" end of the space station's robotic arm and performed a few "get ahead" tasks.