Rapid cellular removal of a membrane-inserted foreign polypeptide.
Ontology highlight
ABSTRACT:
SUBMITTER: Moskaug JO
PROVIDER: S-EPMC1132549 | biostudies-other | 1993 Apr
REPOSITORIES: biostudies-other
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Project description:We describe the benefits of perfluoro-N-octane (PFO), a perfluorocarbon liquid, in the removal of nonmagnetic intraocular foreign bodies (IOFBs) from the macula and posterior segment. Two consecutive cases of posterior segment IOFB were reviewed. An 18-year-old male presented to the emergency room after a motor vehicle accident with a zone 1 open globe injury and large glass IOFB in the left eye. A 53-year-old male presented to the emergency room with a history of a 3-week delayed presentation of a zone 1 open globe injury from a nail to the right eye. He was found to have a metallic IOFB. In both cases, PFO was used to slide the nonmagnetic IOFBs outside of the macula for safer retrieval. PFO was also able to protect the posterior pole from IOFB drops during early attempts at removal. PFO can be a useful surgical adjunct to pars plana vitrectomy in the removal of certain nonmagnetic IOFBs.
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Project description:Objectives:Foreign bodies of the external and middle ear are not uncommon; however, foreign bodies in the eustachian tube are rare. Here we describe the presentation, imaging, and endoscopic-assisted surgical management of a case of eustachian tube foreign body. Methods:A 34-year-old male was seen for evaluation of foreign body of the left eustachian tube while working with metal at a machine shop. Imaging and surgical management are highlighted and review of available literature regarding foreign bodies of the eustachian tube is presented. Results:A CT scan revealed a foreign body present approximately 1?cm into the bony eustachian tube. The patient underwent middle ear exploration which required endoscopic assistance to adequately visualize the foreign body. The foreign body was unable to be removed and required the creation of a bony tunnel lateral to the eustachian tube for visualization and access to the foreign body. Conclusions:This report presents a rare case of eustachian tube foreign body. Use of the endoscope during the surgical removal greatly enhanced the ease and safety of removal. This report also highlights the importance of ear protection with any machining and welding work.
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Project description:This is a prospective clinical assay that included six patients who were diagnosed with penetrating corneal injury, traumatic cataract, and posterior segment intraocular foreign body (IOFB). Following anterior segment repair and extraction of traumatic cataract by clear cornea phacoemulsification, a standard 25-gauge transconjunctival pars plana vitrectomy was performed to find and release the IOFB. With active suction using a 25-gauge silicone tipped cannula, the foreign body was retrieved and safely placed in the anterior chamber. After stabilization of the anterior chamber with viscoelastic injection, IOFB extraction through the main phaco incision was easily performed, followed by placement of an intraocular lens. Of the six patients, 66.6% showed a significant improvement of visual acuity. No complications associated directly with the surgical procedure occurred. Our surgical technique is a safe alternative for handling and removing a posterior IOFB. There was no need for a scleral incision.
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Project description:Amyloid formation by islet amyloid polypeptide (IAPP) contributes to ?-cell dysfunction in type 2 diabetes. Perturbation of the ?-cell membrane may contribute to IAPP-induced toxicity. We examine the effects of lipid composition, salt, and buffer on IAPP amyloid formation and on the ability of IAPP to induce leakage of model membranes. Even low levels of anionic lipids promote amyloid formation and membrane permeabilization. Increasing the percentage of the anionic lipids, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS) or 1,2-dioleoyl-sn-glycero-3-phospho(1'-rac-glycerol), enhances the rate of amyloid formation and increases the level of membrane permeabilization. The choice of zwitterionic lipid has no noticeable effect on membrane-catalyzed amyloid formation but in most cases affects leakage, which tends to decrease in the following order: 1,2-dioleoyl-sn-glycero-3-phosphocholine > 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine > sphingomyelin. Uncharged lipids that increase the level of membrane order weaken the ability of IAPP to induce leakage. Leakage is due predominately to pore formation rather than complete disruption of the vesicles under the conditions used in these studies. Cholesterol at or below physiological levels significantly reduces the rate of vesicle-catalyzed IAPP amyloid formation and decreases the susceptibility to IAPP-induced leakage. The effects of cholesterol on amyloid formation are masked by 25 mol % POPS. Overall, there is a strong inverse correlation between the time to form amyloid and the extent of vesicle leakage. NaCl reduces the rate of membrane-catalyzed amyloid formation by anionic vesicles, but accelerates amyloid formation in solution. The implications for IAPP membrane interactions are discussed, as is the possibility that the loss of phosphatidylserine asymmetry enhances IAPP amyloid formation and membrane damage in vivo via a positive feedback loop.
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Project description:Bladder foreign bodies have been reported with a great variety, including daily objects and even living things. Except for these, thermometer in bladder were reported with several cases. Due to the limitations of surgical equipment, the removal of bladder thermometer was initially performed with manipulation combined with forceps for female patients, and now it has been taken out with the assistance of various endoscopes. In this report, a 25 years old male inserted a thermometer in his bladder, and a transurethral cystoscopic removal procedure was conducted with a stone extractor.
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Project description:BCL-XL is a dominant inhibitor of apoptosis and a significant anti-cancer drug target. Endogenous BCL-XL is integral to the mitochondrial outer membrane (MOM). BCL-XL reconstituted in detergent-free lipid bilayer nanodiscs is anchored to the nanodisc lipid bilayer membrane by tight association of its C-terminal tail, while the N-terminal head retains the canonical structure determined for water-soluble, tail-truncated BCL-XL, with the surface groove solvent-exposed and available for BH3 ligand binding. To better understand the conformation and dynamics of this key region of BCL-XL we have developed methods for isolating the membrane-embedded C-terminal tail from its N-terminal head and for preparing protein suitable for structural and biochemical studies. Here, we outline the methods for sample preparation and characterization and describe previously unreported structural and dynamics features. We show that the C-terminal tail of BCL-XL forms a transmembrane ?-helix that retains a significant degree of conformational dynamics. We also show that the presence of the intact C-terminus destabilizes the soluble state of the protein, and that the small fraction of soluble recombinant protein produced in Escherichia coli is susceptible to proteolytic degradation of C-terminal residues beyond M218. This finding impacts the numerous previous studies where recombinant soluble BCL-XL was presumed to be full-length. Nevertheless, the majority of recombinant BCL-XL produced in E. coli is insoluble and protected from proteolysis. This protein retains the complete C-terminal tail and can be reconstituted in lipid bilayers in a folded and active state.
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Project description:Purpose:To report a novel technique of cross-knotted suture basket and to test its effectiveness in large nonmagnetic intraocular foreign body (IOFB) removal. Methods:A 7/0 Vicryl suture was cut in half and cross-knotted, and four ends were introduced into a 23G needle to form a basket. Pig eyes were used to set up the IOFB model, and the effectiveness of the suture basket in the removal of large nonmagnetic intraocular foreign bodies was tested. Results:Several modifications can be made to adapt to different situations. For the materials (stone, metal, glass, and wood) and shapes (irregular, spherical, and rectangle) of large IOFB tested, the cross-knotted suture basket successfully removed all kinds of IOFBs. Conclusion:The suture basket technique provides an accessible, safe, and effective alternative in large nonmagnetic IOFB removal. It can be adapted and interchangedand also worth's further clinical investigations.
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