949 resultados para giant unilamellar vesicles


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Vesicle fusion is executed via formation of an Ω-shaped structure (Ω-profile), followed by closure (kiss-and-run) or merging of the Ω-profile into the plasma membrane (full fusion). Although Ω-profile closure limits release but recycles vesicles economically, Ω-profile merging facilitates release but couples to classical endocytosis for recycling. Despite its crucial role in determining exocytosis/endocytosis modes, how Ω-profile merging is mediated is poorly understood in endocrine cells and neurons containing small ∼30-300 nm vesicles. Here, using confocal and super-resolution STED imaging, force measurements, pharmacology and gene knockout, we show that dynamic assembly of filamentous actin, involving ATP hydrolysis, N-WASP and formin, mediates Ω-profile merging by providing sufficient plasma membrane tension to shrink the Ω-profile in neuroendocrine chromaffin cells containing ∼300 nm vesicles. Actin-directed compounds also induce Ω-profile accumulation at lamprey synaptic active zones, suggesting that actin may mediate Ω-profile merging at synapses. These results uncover molecular and biophysical mechanisms underlying Ω-profile merging.

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[EN] The Giant Lizard of El Hierro, Gallotia simonyi is one of the most endangered reptile species of the world (Corbett 1989, 1993, Machado et al. 1985). The first scientific news about a living population of G. simonyi dates back to 1975 (Böhme & Bings 1975, 1977; see also Bischoff et al. 1979). The giant lizard, widely distributed in El Hierro in the past (Böhme et al. 1981) is presently restricted to a small area of the Fuga de Gorreta (fig. 1).

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[ES] Una nueva especie de tortuga terrestre extinguida en el Plioceno de Gran Canana es descrita con el nombre de Geochelone vulcanica. La comparación con el material óseo similar de G. burchardi en la isla de Tenerife, demuestra las grandes diferencias existentes entre ambos taxones. Los huevos fósiles de tortugas terrestres descritos en la isla de Gran Canana se consideran pertenecientes a la nueva especie.

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[EN] Gallotia simonyi (Steindachner, 1889) is a member of an endemic Canary Island genus and is among the largest of the approximately 250 recent species of lacertid lizards. Although Steindachner gave the locality of the types as the Roques de Salmor, off El Hierro island, previous workers (Urusaustegui, 1983; Manrique & Saavedra, 1873; Viera & Clavijo, 1983) and subsequent ones (Machado, 1985) regard the more western of the two rocks in the group, the Roque Chico de Salmor, as the actual source of material. The Roque Chico is 37 m high with a surface area of less than 10,000 m2 and lies 830 m from the northern coast of El Hierro (Machado, 1985).

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The premiere of Season Two of Twin Peaks garnered some of the highest ratings of the series, with celebrated filmmaker and co-creator David Lynch stepping back into the director’s chair. Yet, within this episode many traditional television conventions are flouted, and in response the following week the ratings dropped dramatically. From its slow-paced opening scenes in which an old man admonishes the wounded, bleeding protagonist to drink his warm milk before it gets cold, followed by a vision of a giant speaking in riddles, this episode not only tested its audience’s patience but also seemed to set out to deliberately confuse them. In this essay I will explore how this episode is an example of auteur television, an episode in which the director expresses a consistency of style and theme that is similar to their other work, as well as examine how Lynch’s approach to televisual aesthetics has influenced the way that contemporary film directors have crossed over into the television medium. However, when taking into account the differences in the two media of film and television notions of authorship, with regards to the position of the director, become complicated, especially when considering contemporary television and the rise of the showrunner as key creative force. Even when looking back at Lynch’s contribution to Twin Peaks it becomes clear that the series was deeply collaborative, with Lynch absent during parts of the filming. Yet, when examining the extensive material that has been written about Twin Peaks there is still a continuing tendency to place Lynch as the sole author. The placement of Lynch as author can be argued in relation to the episodes he directed (as will be explored below in relation to the first episode of Season Two), but cannot be attributed to him alone when considering the series as a whole. Finally, I will discuss how the figure of the television auteur has become a central element of television reception rather than production, an integral part of a viewer’s search for narrative meaning in a medium where complexity and mystery are now expected and enjoyed. Just as fans scrambled to uncover the many secrets and mysteries of Twin Peaks by looking to Lynch’s other works for answers, a similar process is experienced by fans of television shows existing today.

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Giant cell arteritis (GCA) or Horton's disease is a systemic granulomatous vasculitis of medium–and large–sized arteries. This is an antigen–driven disease with local T–cell and macrophage activation in the vessel wall and with an important role of proinflammatory cytokines. GCA is also called “temporal arteritis” because it involves often the superficial temporal arteries. The condition affects especially the extracranial branches of the carotid artery, but recently, GCA has been recognised to also affect limb arteries and the aorta with high prevalence.

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Hemangioma is the most common benign tumor of the liver and it is often asymptomatic. Spontaneous rupture of liver hemangiomas is a rare but potentially lethal complication. Emergent hepatic resection has been the treatment of choice but carries high operative morbidity and mortality. Recently, preoperative transcatheter arterial embolization (TAE) has been used successfully for the management of bleeding ruptured liver tumors and non-operative treatment of symptomatic giant liver hemangiomas. We report a case of spontaneous rupture of a giant hepatic hemangioma that presented with thoracic and abdominal pain and shock due to hemoperitoneum. Once proper diagnosis was made the patient was successfully managed by TAE, followed by conservative hepatic resection.

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Most cases of Meckel’s diverticulum (MD) are asymptomatic and discovered by chance. Management of MD is controversial. The authors describe an exceptional case of intestinal obstruction caused by a giant MD in a patient who had previously undergone appendectomy. A review of the contradictory literature on this subject leads to the conclusion that careful consideration of clinical and morphological data (patient's age, ASA score, the surgical procedure to be performed, morphology and position of the MD, any fibrotic bands) is required before deciding whether or not to resect an asymptomatic MD.

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Lymphoepithelioma-like gastric carcinoma (LELGC) has special clinicopathologic features that differentiate it from the common gastric adenocarcinoma. LELGC is a rare neoplasm of the stomach with an incidence of 1-4% of all gastric cancers and is characterized by desmoplastic stroma uniformaly infiltrated by abundant lymphocytes and plasma cells. LELGC is closely associated with the Epstein-Barr virus (EBV), with 80-100% of LELGC being EBV-positive. LELGC has a male predominance, occurs in elderly people and is usually located in the upper and middle portion of the stomach. We report a rare case of lymphoepithelioma-like gastric carcinoma located in the lesser curvature at the border of the gastric body to the pyloric antrum.

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We report the case of a 82-year-old woman, asymptomatic, subject to chest computed tomography for trauma. Then the patient underwent surgery. Before sternotomy, femoro-femoral bypass was starter in order to decompress the aneurysm; using deep hypothermia and circulatory arrest, ascending aorta and hemiarch replacement were performed with a Dacron graft. Post-operative course was uneventful.

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The authors present a case of giant papillary adenoma of the breast and discuss their therapeutic strategy. The patient subsequently returned due to a local recurrence, which was treated with oncoplastic surgery, with satisfactory aesthetic results. The authors conclude by stressing the considerable rarity of this disease and the need for effective cooperation between surgeons and pathologists.

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A perineal hernia is defined as a protrusion of peritoneal or extraperitoneal content through a pelvic floor defect. A 64-year-old woman with a bowel occlusions due to a giant postoperative perineal hernia was admitted to our hospital. We describe abdominal approach with plastic perineal reconstruction.

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Type 1 neurofibromatosis is a relatively common inherited disease of the nervous system, with a frequency of almost 1 in 3000. It is associated with neurofibromas of various sites. Our case report is about the surgical management of a giant neurofibroma of the right gluteal fold in a 46-year-old male with NF1. The patient presented with increasing edema and accelerated growth of the mass; he underwent percutaneous embolization of lesion vessels that induced necrosis of the neurofibroma. The patient was taken to the operating room, where surgical resection of the bulk of the lesion was undertaken. The postoperative course was complicated by delayed wound closure managed with antibiotics and vacuum-assisted wound closure. Giant neurofibromas similar to this tumor require complex preoperative, intraoperative and postoperative management strategies. Surgical debulk is best managed with preoperative percutaneous embolization that help to avoid surgical bleeding. Postoperative delayed wound closure was managed with the application of negative pressure in a closed environment that triggers granulation and tissue formation.

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Background. Giant Condyloma Acuminatum (GCA) is a rare, slow growing, large cauliflower tumor of the penile foreskin and perianal region with benign histologic appearance but high propensity for local invasion and recurrences. GCA is associated with Human Papilloma Virus (HPV) types 6 and 11 and it also has considerable risk of neoplastic transformation into fully invasive squamous cell carcinoma into about 5 years. Objective. Because of the rarity of perianal GCA, to date there is no general agreement on the best method for treatment. We wanted to know if surgical approach only was a good method to treat our case. Case report. A 28 years old man, HIV-negative, with a 4 years history of perianal GCA quickly growing underwent full tickness local excision at least 0,7 cm margin of normal tissue with skin grafting taken from the thighs. Fecal contamination was avoided by diet and loperamide per os. At two years follow-up no recurrence was detected. Conclusion. Surgical approach with full tickness excision and immediate skin-grafting and regular follow-up demonstrated effective to treat GCA and to minimize disease recurrence.