986 resultados para APICAL LEAKAGE


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Water balance is achieved through the ability of the kidney to control water reabsorption in the connecting tubule and the collecting duct. In a mouse cortical collecting duct cell line (mCCD(c11)), physiological concentrations of arginine vasopressin increased both electrogenic, amiloride-sensitive, epithelial sodium channel (ENaC)-mediated sodium transport measured by the short-circuit current (Isc) method and water flow (Jv apical to basal) measured by gravimetry with similar activation coefficient K(1/2) (6 and 12 pM, respectively). Jv increased linearly according to the osmotic gradient across the monolayer. A small but highly significant Jv was also measured under isoosmotic conditions. To test the coupling between sodium reabsorption and water flow, mCCD(c11) cells were treated for 24 h under isoosmotic condition with either diluent, amiloride, vasopressin or vasopressin and amiloride. Isc, Jv, and net chemical sodium fluxes were measured across the same monolayers. Around 30% of baseline and 50% of vasopressin-induced water flow is coupled to an amiloride-sensitive, ENaC-mediated, electrogenic sodium transport, whereas the remaining flow is coupled to an amiloride-insensitive, nonelectrogenic sodium transport mediated by an unknown electroneutral transporter. The mCCD(c11) cell line is a first example of a mammalian tight epithelium allowing quantitative study of the coupling between sodium and water transport. Our data are consistent with the 'near isoosmotic' fluid transport model.

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Purpose: Pathologic choroidal neovascularizations (CNV) are implicated in the wet form of age-related macular degeneration (ARMD). Abnormal vessel growth is also observed in disease when hypoxia and/or inflammation occur. Our goal is to establish a standard protocol of laser-induced CNV in mice that have different levels of pigmentation to identify the most reliable animal model.Methods: CNV was induced by 4 burns around the optic disk, using a green argon laser (100μm diameter spot size; 0,05 sec. duration) in C57/Bl6, DBA/1 and Balb/c to ascertain the efficacy of the method in function of retina pigmentation. Five different intensities were tested and Bruch's membrane disruption was identified by the appearance of a bubble at the site of photocoagulation. Fluorescein angiographies (FA) were undertaken 14 days post lesion and CNV area was quantified by immunohistochemistry on cryosections.Results: CNV retina area was related to spot intensity after laser injury. While 180mW and 200mW do not induce reliable CNV (respectively 27.85±0.35% and 29±1.67% of the retina surface), 260mW is required to induce 51,07±8.52% of CNV in C57/Bl6 mice. For the DBA/1 strain, less pigmented, 200mW was sufficient to induce 49.35±3.9% of CNV, indicating that lower intensity are required to induce CNV. Furthermore, an intensity of 180mW induced greater CNV (35.55±6.01%) than in C57/Bl6 mice. Nevertheless, laser did not induce reproducible 50% CNV in Balb/c albino mice for all intensities tested. Isolectin-B4 and GFAP stainings revealed neovessel formation and photoreceptor (PR) degeneration at the impact site. The presence of glia was observed throughout all the retinal layers and angiograms showed fluorescein leakage in pigmented mice.Conclusions: The establishment of a standard protocol to induce CNV and subsequent PR degeneration is of prime importance for the use of the laser-induced CNV model and will allow to evaluate the therapeutic potency of agents to prevent CNV and retinal degeneration.

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The aim of this work was to use the Urinary Distress Inventory (UDI-6) and Incontinence Impact Quality of Life (IIQ-7) questionnaires to compare 3 surgical techniques for stress urinary incontinence: the transvaginal tape (TVT) (105 women), the transobturator tape outside-in (TOT) (43 women), and the transvaginal tape-obturator inside-out (TVT-O) (54 women). There were no significant differences in frequent urination, urine leakage related to the feeling of urgency, urine leakage related to physical activity, or small amounts of urine leakage. TVT-operated women had a lower percentage of micturition difficulties compared with TOT women. TVT-O-operated women described slight discomfort in the genital area compared with the TVT technique, but this difference was not significant when compared with the TOT technique. When utilizing the UDI-6 and IIQ-7 scoring modifications before and after surgery, no difference among these 3 techniques is apparent.

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Purpose:To describe the indications, the surgical procedure and the clinical outcome of MLAM in the treatment of non traumatic corneal perforations and descemetoceles . Methods:A prospective, non comparative, interventional case series of eight consecutive patients (mean age 59 years old, 6 men and 2 women) with non traumatic corneal perforations or descemetoceles.The surgery consisted in a MLAM transplantation of a cryopreservated human amniotic membrane. The series included: three active herpetic keratitis, one rosacea, one perforation of an hydrops, one cicatricial pemphigoid, one perforation after an abcess in a corneal graft and one perforation after protonbeamtherapy. The clinical outcome included: the follow-up, the integrity of the eye, corneal epithelialization, inflammation and neovascularization, and the integration of the MLAM. Stromal thickness was followed precisely with the slit lamp. A corneal graft was performed at one patient after the MLAM, allowing microscopic investigation of the removed MLAM integrated in the cornea. Results:The mean follow-up was 8.78 months (range 3.57 to 30.17). Amniotic membrane transplantation was successful and reduced inflammation in 7 patients out of 8 ,after one procedure.One patient who presented a large herpetic keratitis epithelial defect with corneal anaesthesia had his MLAM dissolved after two weeks with an aqueous leakage. Epithelium healed within 3 weeks above 7 MLAM and remained stable at 3 months in 7 out of 8 patients. MLAM opacification gradually disappeared over a few months, however, stromal layers filling in the corneal perforations or above the descemetoceles remained stable. Conclusions:MLAM transplantation is a safe, effective and useful technique to cure non traumatic corneal perforations and descemetoceles. It can be performed in emergency despite the presence of an active inflammation or infection. By facilitating epithelialization, reducing inflammation and neovascularization, it allows corneal surface reconstruction in patients with persistent epithelial defects and corneal melting that usually ends in a perforation. For full visual rehabilitation, a delayed penetrating keratoplasty is required.

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Tako-tsubo cardiomyopathy or "transient left ventricular (LV) apical ballooning" clinically presents like acute myocardial infarction without angiographic stenosis on coronary angiogram and a transient (reversible) LV apical ballooning. We discuss here about a 56-year-old woman complains of first constrictive chest pain with ST elevation in leads V2-V6 and minimal enzymatic release. Coronary angiogram demonstrates vessels without stenosis and the left ventriculogram an extensive LV apical wall motion abnormalities. LV dysfunction will only be transient since 24 hours after admission echographic images demonstrate quite complete recovery of LV systolic function. The pain disappears 12 hours after admission and the creatine kinase level normalize after 48 hours.

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In addition to the ubiquitous apical-basal polarity, epithelial cells are often polarized within the plane of the tissue - the phenomenon known as planar cell polarity (PCP). In Drosophila, manifestations of PCP are visible in the eye, wing, and cuticle. Several components of the PCP signaling have been characterized in flies and vertebrates, including the heterotrimeric Go protein. However, Go signaling partners in PCP remain largely unknown. Using a genetic screen we uncover Kermit, previously implicated in G protein and PCP signaling, as a novel binding partner of Go. Through pull-down and genetic interaction studies, we find that Kermit interacts with Go and another PCP component Vang, known to undergo intracellular relocalization during PCP establishment. We further demonstrate that the activity of Kermit in PCP differentially relies on the motor proteins: the microtubule-based dynein and kinesin motors and the actin-based myosin VI. Our results place Kermit as a potential transducer of Go, linking Vang with motor proteins for its delivery to dedicated cellular compartments during PCP establishment.

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The family of death domain (DD)-containing proteins are involved in many cellular processes, including apoptosis, inflammation and development. One of these molecules, the adapter protein MyD88, is a key factor in innate and adaptive immunity that integrates signals from the Toll-like receptor/interleukin (IL)-1 receptor (TLR/IL-1R) superfamily by providing an activation platform for IL-1R-associated kinases (IRAKs). Here we show that the DD-containing protein Unc5CL (also known as ZUD) is involved in a novel MyD88-independent mode of IRAK signaling that culminates in the activation of the transcription factor nuclear factor kappa B (NF-κB) and c-Jun N-terminal kinase. Unc5CL required IRAK1, IRAK4 and TNF receptor-associated factor 6 but not MyD88 for its ability to activate these pathways. Interestingly, the protein is constitutively autoproteolytically processed, and is anchored by its N-terminus specifically to the apical face of mucosal epithelial cells. Transcriptional profiling identified mainly chemokines, including IL-8, CXCL1 and CCL20 as Unc5CL target genes. Its prominent expression in mucosal tissues, as well as its ability to induce a pro-inflammatory program in cells, suggests that Unc5CL is a factor in epithelial inflammation and immunity as well as a candidate gene involved in mucosal diseases such as inflammatory bowel disease.

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Host part selection by ovipositing females of Ascia monuste (Godart, 1919) (Lepidoptera, Pieridae) on kale (Brassica oleracea var. acephala) was determined in greenhouse and field. Performance of offspring (larval period, efficiency of food utilization, number of eggs/female and others) was investigated under laboratory conditions. In the field, the number of A. monuste egg clutches on the apical and medium parts of kale leaves was greater than on the basal part. In greenhouse, A. monuste exhibited a strong preference for the apical part of kale leaves for ovipositing. The best results on food utilization indices, pupal mass and female wing size were obtained with the leaf apical part. This part of kale leaves exhibited the highest nitrogen and protein concentration and the smallest water content, when compared to the other leaf parts. However, the apical part of the leaves seems not to provide ovipositing females with enough protection against birds, making them easy preys in the field. We suggest that good relationship between oviposition preference and performance of offspring was hindered by predation in field conditions.

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The occurrence, morphology and ultrastructure of the Dufour gland in Melipona bicolor Lepeletier, 1836 are presented. The Dufour gland is not present in workers. In virgin queens the gland cells show characteristics of low activity, which are described in the text. In physogastric queens the gland epithelium is higher and the cells more active than in virgin queens, showing numerous basal plasmic membrane invaginations impregnated by an electrondense material, increased apical invaginations and accumulation of substances that will be released to the gland lumen in the subcuticular space. Therefore, the data show that the Dufour gland is more developed in physogastric than in virgin queens, indicating a possible involvement of the Dufour gland in the reproduction of this species.

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Overactive bladder (OAB) is a prevalent condition with 16% of adults having one or more symptoms that significantly affect quality of life. Transcutaneous electrical nerve stimulation and neuromodulators have had success in treating OAB but are expensive, invasive, and sometimes cumbersome. We developed an alternative neuromodulatory technique that involves electromagnetic stimulation of the sacral nerve roots with a portable electromagnetic device to produce trans-sacral stimulation of the S3 and S4 sacral nerve roots. The aim of this study was to evaluate the impact of this device on OAB symptoms in women with a prospectively randomised double-blind controlled study. Following a power analysis, women with symptoms of OAB were prospectively recruited with ethical approval for randomisation to an active treatment (n = 33) or placebo group (n = 30) in a double-blind trial. The patient, at home, used the belt device daily for 20 min over 12 weeks. Outcome measures included a 3-day voiding diary, 1 h pad test, visual analogue score (VAS) for symptom impact (0-100%), Kings Health Questionnaire (KHQ) and Australian Quality of Life questionnaire (AQOL) at baseline, 6 and 12 weeks. Overall, no difference was found between groups for any of the research questions. Specifically, we were unable to demonstrate any difference between the active and sham device groups in frequency, nocturia, urinary leakage, or quality of life, nor was there any evidence of a placebo effect. The quality of the data was high with the number of missing observations (especially for disease specific KHQ and general AQOL) being few. This attempt to promote trans-sacral electromagnetic neuromodulation with a specially created device was ineffective on the symptoms of OAB.

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We develop a setting with weak intellectual property rights, where firms' boundaries, location and knowledge spillovers are endogenous. We have two main results. The first one is that, if communication costs increase with distance, entrepreneurs concerned about information leakage have a benefit from locating away from the industry center: distance is an obstacle to collusive trades between members andnon-members. The second result is that we identify a trade-off for the entrepreneur between owning a facility (controlling all its characteristics) and sharing a facility with a {\it non-member} (an agent not involved in production), therefore losing control over some of its characteristics. We focus on ``location" as the relevant characteristic of the facility, but location can be used as a spatial metaphor for other relevant characteristics of the facility. For theentrepreneur, sharing the facility with non-members implies that the latter, as co-owners, know the location (even if they do not have access to it). Knowledge of the location for the co-owners facilitates collusion with employees, what increases leakage. The model yields a benefit for new plants from spatial dispersion (locating at the periphery of the industry), particularly so for new plants of new firms.We relate this result with recent empirical findings on the dynamics of industry location.

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The aim of this study was to determine whether multiwalled carbon nanotubes (MWNCT) are taken up by and are toxic to human intestinal enterocytes using the Caco-2 cell model. Caco-2 cells were exposed to 50 ?g/ml MWCNT (oxidized or pristine) for 24 h, and experiments were repeated in the presence of 2.5 mg/L natural organic matter. Cells displayed many of the properties that characterize enterocytes, such as apical microvilli, basolateral basement membrane, and glycogen. The cell monolayers also displayed tight junctions and electrical resistance. Exposure to pristine and oxidized MWCNT, with or without natural organic matter, did not markedly affect viability, which was assessed by measuring activity of released lactate dehydrogenase (LDH) and staining with propidium iodide. Ultrastructural analysis revealed some damage to microvilli colocalized with the MWCNT; however, neither type of MWCNT was taken up by Caco-2 cells. In contrast, pristine and oxidized MWCNT were taken up by the macrophage RAW 264.7 line. Our study suggests that intestinal enterocytes cells do not take up MWCNT. [Authors]

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The cortical collecting duct (CCD) plays a key role in regulated K(+) secretion, which is mediated mainly through renal outer medullary K(+) (ROMK) channels located in the apical membrane. However, the mechanisms of the regulation of urinary K(+) excretion with regard to K(+) balance are not well known. We took advantage of a recently established mouse CCD cell line (mCCD(cl1)) to investigate the regulation of K(+) secretion by mineralocorticoid and K(+) concentration. We show that this cell line expresses ROMK mRNA and a barium-sensitive K(+) conductance in its apical membrane. As this conductance is sensitive to tertiapin-Q, with an apparent affinity of 6 nM, and to intracellular acidification, it is probably mediated by ROMK. Overnight exposure to 100 nM aldosterone did not significantly change the K(+) conductance, while it increased the amiloride-sensitive Na(+) transport. Overnight exposure to a high K(+) (7 mM) concentration produced a small but significant increase in the apical membrane barium-sensitive K(+) conductance. The mRNA levels of all ROMK isoforms measured by qRT-PCR were not changed by altering the basolateral K(+) concentration but were decreased by 15-45% upon treatment with aldosterone (0.3 or 300 nM for 1 and 3 h). The paradoxical response of ROMK expression to aldosterone could possibly work as a preventative mechanism to avoid excessive K(+) loss which would otherwise result from the increased electrogenic Na(+) transport and associated depolarization of the apical membrane in the CCD. In conclusion, mCCD(cl1) cells demonstrate a significant K(+) secretion, probably mediated by ROMK, which is not stimulated by aldosterone but increased by overnight exposure to a high K(+) concentration.

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The elytro-tergal stridulatory organ that occurs in Bondarius Rosado-Neto, 2006 a genus of the tribe Sternechini (Curculionidae, Molytinae) is described and illustrated. The stridulatory apparatus is present both in male and female and is composed by the file, a narrow elevated carina which is transversely multistriate located at the apical third of the internal side near the suture of left elytron, and by the plectrum, a narrow striate area located transversely at the dorso-apical margin of the abdominal tergite 7.

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Se describe e ilustran los adultos y genitalia de macho y hembra de Copitarsia uncilata Burgos & Leiva sp. nov., que se distribuye en Colombia y México. La nueva especie se caracteriza por poseer un uncus ancho apicalmente espatulado con una diminuta proyección dorsal bulbosa, digitus de corte apical ampliamente cóncavo y una ampulla con ápice recurvado que sobresale de la valva, externamente es similar a Copitarsia decolora (Guenée).