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INTRODUCTION AND OBJECTIVE: The importance of evaluating the self-esteem and quality of life of patients with a chronic disease has become increasingly relevant. The study describes self-esteem and quality of life outcomes in patients with neurogenic dysfunction and continent urinary diversions and/or antegrade enema procedures. MATERIALS AND METHODS: Cross-sectional observational study, including patients with neurogenic dysfunction who required a continent urinary diversion and/or an antegrade enema conduit during their treatment. The self-esteem evaluation was done with the Rosenberg scale and the quality of life with the KIDSCREEN-27 questionnaire. VARIABLES MEASURED: socio-demographic, clinical and economic characteristics. Descriptive statistics were applied. RESULTS: The mean age of the 9 patients was 15.6 years, the mean time elapsed from surgery to application of the questionnaires was 60.9⯱â¯37.1 months. With a perception of improvement in 8 of the 9 patients and a normal or higher self-esteem score in all cases. In the description of physical activity and health, it was found that 7 of the 9 young people presented a perception of good health in general. A considerable reduction in the use of diapers was achieved after the intervention, going from consuming 6.2⯱â¯1.4 diapers per day to only 1.7⯱â¯1.3 diapers per day. CONCLUSIONS: Despite the sequelae, comorbidities and procedures, the results of self-esteem and quality of life in patients with neurogenic dysfunction are high.
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Qualidade de Vida , Derivação Urinária , Humanos , Adolescente , Estudos Transversais , Derivação Urinária/efeitos adversos , Enema/métodos , Autoavaliação DiagnósticaRESUMO
In this article, the classical Rayleigh-Taylor instability is extended to situations where the fluid is completely confined, in both the vertical and horizontal directions. This article starts with the two-dimensional (2D) viscous periodic case with finite height where the effect of adding surface tension to the interface is analyzed. This problem is simulated from a dual perspective: first, the linear stability analysis obtained when the Navier-Stokes equations are linearized and regularized in terms of density and viscosity; and second, looking at the weakly compressible version of a multiphase smoothed particle hydrodynamics (WCSPH) method. The evolution and growth rates of the different fluid variables during the linear regime of the SPH simulation are compared to the computation of the eigenvalues and eigenfunctions of the viscous version of the Rayleigh-Taylor stability (VRTI) analysis with and without surface tension. The most unstable mode, which has the maximal linear growth rate obtained with both approaches, as well as other less unstable modes with more complex structures are reported. The classical horizontally periodic (VRTI) case is now adapted to the case where two additional left and right walls are included in the problem, representing the cases where a two-phase flow is confined in a accelerated tank. This 2D case where no periodic assumptions are allowed is also solved using both techniques with tanks of different sizes and a wide range of Atwood numbers. The agreement with the linear stability analysis obtained by a Lagrangian method such as multiphase WCSPH is remarkable.
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In this article, the computation of the linear growth rates and eigenfunctions of the viscous version of the Rayleigh-Taylor instability by numerically solving the corresponding eigenvalue problem in the case of one-dimensional (1D) and two-dimensional (2D) geometries is studied. The 1D version is first validated in the particular inviscid case to be compared to the previous literature. The most unstable mode, also known as the first mode, which has the maximal linear growth rate has been extensively studied in previous literature. Higher modes have smaller eigenvalues, but the corresponding eigenfunctions present a more complex structure that contains multipeak shapes. In the extension to the 2D geometry, the length of the domain limits the wave number of the eigenvectors computed. In the extension to the 2D geometry the length of the domain limits the wave number of the eigenvectors computed. The importance of extending the results to the two-dimensional case is twofold. First, it opens up the possibility of generalizing the computation to more complex geometries that could contain fixed or floating objects and, second, allows the computation of flow instabilities in nonzero basic flows that could come from the steady Navier-Stokes solutions.
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INTRODUCTION: The management of severely traumatized extremity continues to be a matter of debate. Gustilo-Anderson tibial fractures III-B have a wide spectrum of variants, there are no guidelines using this classification for management. MESS has demonstrated functional and prognostic association. OBJECTIVE: To identify the pattern of decision made by surgeons for the prescription of amputations in tibial fractures exposed grade III-B Gustilo-Anderson with MESS scale. Material and methods. RESULTS: There was no association between the variables, with the application of MESS. (2 = 1.28, p = 0.2575). Surgeons of more than 10 years, increased once the possibility of matching the result of experts (OR = 2.088, 95% CI) (p = 0.0066). CONCLUSION: Academic degrees, surgical experience, and frequent clinical practice do not influence the correct application of the MESS scale. Surgeons with more than 10 years of experience have doubled the possibility of a precise decision.
INTRODUCCIÓN: El manejo de la extremidad severamente traumatizada continúa siendo materia de debate. Las fracturas de tibia III-B de Gustilo-Anderson tienen un amplio espectro de variantes, no hay guías mediante esta clasificación para un manejo. MESS ha demostrado asociación funcional y pronóstica. OBJETIVO: Identificar el patrón de decisión por parte de los cirujanos para la prescripción de amputaciones en fracturas de tibia expuesta grado IIIB Gustilo-Anderson con escala MESS. MATERIAL Y MÉTODOS: Es un estudio descriptivo, observacional, prospectivo, transversal y analítico. Se evaluaron 131 ortopedistas de un centro de referencia de patología traumática, quienes con uso de la escala MESS evaluaron 10 casos clínicos representativos de fracturas de tibia expuesta grado III-B de Gustilo-Anderson presentados en dispositivo electrónico. Se evaluó la concordancia de las decisiones entre cirujanos que laboran y expertos. Se realizó análisis inferencial mediante 2 (p 0.05) de las variables del estudio: experiencia del cirujano, postgrados académicos, práctica clínica frecuente de amputaciones, concordancia de las decisiones con escala MESS con respecto al patrón de prescripción obtenido por expertos. RESULTADOS: No se encontró asociación entre las variables con la aplicación de MESS (2 = 1.28, p = 0.2575). Los cirujanos de más de 10 años incrementaron una vez la posibilidad de coincidir con el resultado de expertos (OR = 2.088, IC 95%) (p = 0.0066). CONCLUSIÓN: Las variables como postgrados académicos, experiencia quirúrgica y práctica clínica frecuente no influyen en la correcta aplicación de la escala MESS. Los cirujanos de más de 10 años de experiencia incrementaron al doble la posibilidad de una decisión precisa.
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Amputação Cirúrgica , Fraturas Expostas , Fraturas da Tíbia , Tomada de Decisões , Fraturas Expostas/cirurgia , Humanos , Prognóstico , Estudos Retrospectivos , Tíbia , Fraturas da Tíbia/cirurgiaRESUMO
BACKGROUND: Simultaneous pancreas-kidney transplantation (SPK) has become the treatment of choice for type 1 diabetes mellitus (T1DM) patients with chronic renal failure. Type 2 diabetes mellitus (T2DM), was once considered to be a contraindication for pancreas transplantation; however, it has been accepted as a new indication, under strict criteria. Although favorable results have increase the indication for T2DM in developed countries, there have been no reports of long-term results for this indication from Latin American centers. METHODS: From April 2008 to March 2016, patients receiving SPK or pancreas transplant alone (PTA) for T2DM were included and compared with T1DM recipients. Variables were compared between groups with the use of χ2 and t tests; Kaplan-Meier with log rank was used for patient and graft survivals; P < .05 was considered to be significant. RESULTS: A total of 45 SPK and 1 PTA were performed, 35 (76.1%) for T1DM and 11 (24.5%) for T2DM. Mean pre-transplantation C-peptide was significantly higher in the T2DM group (P = .01); HbA1c was higher in the T1DM group (P = .03). No differences were found in weight, body mass index, and pre-transplantation glycemia. Patient survivals for T1DM recipients were 88.2% and 84.8% at 1 and 5 years, respetively, versus 100% and 74.1% for T2DM recipients (P = .87). CONCLUSIONS: Our initial prospective experience in a single Latin American center showed that medium- and long-term outcomes for T1DM and T2DM individuals receiving pancreas transplants are similar, under strict selection criteria.
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Diabetes Mellitus Tipo 1/cirurgia , Diabetes Mellitus Tipo 2/cirurgia , Transplante de Pâncreas/métodos , Adulto , Feminino , Sobrevivência de Enxerto , Humanos , Falência Renal Crônica/cirurgia , Transplante de Rim/efeitos adversos , Transplante de Rim/métodos , América Latina , Masculino , Pessoa de Meia-Idade , Transplante de Pâncreas/efeitos adversos , Estudos Prospectivos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
To compare the three-dimensional changes occurring in the maxillary arch during the use of modified pre-surgical nasoalveolar moulding (PNAM) and Hotz's plate. A clinical trial including 32 children with unilateral cleft lip and palate (UCLP), 16 treated with Hotz's plate and 16 with PNAM, was performed. Impressions of the maxillary arches were taken: A. prior to pre-surgical orthopaedics, B. before cheiloplasty and C. after cheiloplasty. Models were digitised using a stereophotogrammetric instrument, and geodesic distances were calculated: anterior, canine and posterior widths of the arch, and lengths and cleft depths of the larger and shorter segments. The time and treatment effects were assessed by two-factor anova. A significant effect of treatment was found for cleft depth at the larger segment: children treated with Hotz's plate had significantly deeper cleft than children treated with PNAM. All distances significantly changed during time: the anterior and canine widths decreased, while the posterior width, the lengths and depths of the cleft segments increased. Significant treatment per time interactions was found. The anterior and canine widths reduced more with PNAM between time points A and B while Hotz's treatment was more effective between B and C. The shorter segment depth increased more between B and C with PNAM, and between A and B with Hotz's plate. During pre-surgical orthopaedics, therapy with PNAM obtained the best results in reducing the width at the anterior segment of the cleft. This treatment gave a lower increase in cleft depth than treatment with Hotz's plate.
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Processo Alveolar/cirurgia , Fenda Labial/cirurgia , Fissura Palatina/cirurgia , Procedimentos Ortopédicos/métodos , Obturadores Palatinos , Humanos , Imageamento Tridimensional , Lactente , Fotogrametria , Resultado do TratamentoRESUMO
Sphingomyelin derivatives like sphingosine have been shown to enhance secretion in a variety of systems, including neuroendocrine and neuronal cells. By studying the mechanisms underlying this effect, we demonstrate here that sphingomyelin rafts co-localize strongly with synaptosomal-associated protein of 25Kda (SNAP-25) clusters in cultured bovine chromaffin cells and that they appear to be linked in a dynamic manner. In functional terms, when cultured rat chromaffin cells are treated with sphingomyelinase (SMase), producing sphingomyelin derivatives, the secretion elicited by repetitive depolarizations is enhanced. This increase was independent of cell size and it was significant 15min after initiating stimulation. Interestingly, by evaluating the membrane capacitance we found that the events in control untreated cells corresponded to two populations of microvesicles and granules, and the fusion of both these populations is clearly enhanced after treatment with SMase. Furthermore, SMase does not increase the size of chromaffin granules. Together, these results strongly suggest that SNARE-mediated exocytosis is enhanced by the generation of SMase derivatives, reflecting an increase in the frequency of fusion of both microvesicles and chromaffin granules rather than an increase in the size of these vesicles.
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Células Cromafins/citologia , Grânulos Cromafim/fisiologia , Exocitose/fisiologia , Esfingomielinas/metabolismo , Proteína 25 Associada a Sinaptossoma/metabolismo , Animais , Fenômenos Biofísicos/efeitos dos fármacos , Bovinos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Micropartículas Derivadas de Células/efeitos dos fármacos , Micropartículas Derivadas de Células/fisiologia , Células Cultivadas , Células Cromafins/efeitos dos fármacos , Grânulos Cromafim/efeitos dos fármacos , Grânulos Cromafim/ultraestrutura , Capacitância Elétrica , Exocitose/efeitos dos fármacos , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Microscopia Eletrônica , Técnicas de Patch-Clamp , Proteínas SNARE/metabolismo , Esfingomielina Fosfodiesterase/farmacologia , Estatísticas não Paramétricas , Proteína 25 Associada a Sinaptossoma/genética , TransfecçãoRESUMO
INTRODUCTION: Autoamputation refers to a situation in which a tubo-ovarian remnant is found free-floating in the abdomino-pelvis, which is a complication of fetal ovarian cyst causing ovarian torsion in uterus. There have been only 13 reported cases of ovarian autoamputation involving children under 1 years of age. CLINICAL CASE: We present the case of a 9-month old female with history of abdominal mass in the 26th week of gestation, who was referred to the pediatric surgery department with CT findings in an abdominal tumor and negative physical examination, in laparoscopic examination cystic mass is 6 cm in diameter and no left ovary. The histopathological examination confirmed an ovarian cyst with necrotic and hemorrhagic remaining. COMMENTATION: This case is reported because of the low incidence of pathology, exceptional presentation and the favorable outcome of the patient with implemented laparoscopic management.
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Laparoscopia , Cistos Ovarianos/complicações , Cistos Ovarianos/cirurgia , Feminino , Humanos , LactenteRESUMO
Hispano-Breton (HB) is a horse breed with a recent mixed ancestry. It was developed in the 1930s by crossing local mares with Breton draught horses imported from France. Nowadays it is considered to be in a vulnerable situation due to census decline. To genetically characterize the breed and to set up the basis for a conservation programme, we have employed two types of molecular markers: a 347-bp D-loop mitochondrial DNA (mtDNA) fragment and 13 microsatellite loci. A representative sample of 53 HB individuals was analysed together with a sample of 40 Pura Raza Española horses for comparison. Both types of markers revealed a high level of genetic diversity in the HB breed, emphasizing the importance of its conservation. The construction of a phylogenetic network with mtDNA sequences including various Iberian breeds and European heavy horses provided an overall picture of the ubiquitous appearance of HB matrilines with respect to other breeds and revealed the singularity of certain HB maternal lineages. Despite the high allelic richness found in HB horses, microsatellite analysis evidenced a certain degree of inbreeding as a consequence of the type of management generally used for local breeds.
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Variação Genética , Cavalos/genética , Animais , DNA Mitocondrial/genética , Especiação Genética , Cavalos/classificação , Repetições de Microssatélites , Especificidade da EspécieRESUMO
Chromaffin cell exocytosis is a fascinating interplay between secretory vesicles and cellular components. One of these components is the cytoskeleton and its associated regulatory proteins. Transport of chromaffin secretory granules from their site of biosynthesis towards the active site of exocytosis requires both F-actin fine remodelling as well as microtubule trails. At least two molecular motors, myosins II and V, seem to play a crucial role in the control of F-actin dynamics and vectorial vesicle displacement respectively. Vesicle movement experiences spatial restrictions as they approach the cell cortical region, where the F-actin meshwork constitutes a barrier-limiting vesicle access to the plasmalemma. During secretion, cortical F-actin is locally disrupted providing access of vesicles to release sites on the plasmalemma. Removal of the stimulus restores cortical F-actin. Two pathways (Ca2+-scinderin and PKC-MARCKS) control F-actin changes during the secretory cycle . Furthermore, GTPases such as RhoA, that controls F-actin network integrity, and Cdc42 signalling which induces the formation of local actin filaments at active sites, provide additional evidence on the importance of F-actin as a key element in vesicle transport and in the exocytotic machinery of chromaffin cells.
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Células Cromafins/metabolismo , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Actinas/metabolismo , Animais , Células Cromafins/ultraestrutura , Grânulos Cromafim/fisiologia , Grânulos Cromafim/ultraestrutura , Citoesqueleto/ultraestrutura , Exocitose , Humanos , Microscopia Confocal , Miosinas/metabolismoRESUMO
Dense vesicles can be observed in live bovine chromaffin cells using fluorescent reflection confocal microscopy. These vesicles display a similar distribution, cytoplasmic density and average size as the chromaffin granules visualized by electron microscopy. In addition, the acidic vesicles labeled with Lysotracker Red comprised a subpopulation of the vesicles that are visualized by reflection fluorescence. A combination of fluorescence reflection and transmitted light images permitted the movements of vesicles in relation to the cortical cytoskeleton to be studied. The movement of vesicles located on the outside of this structure was restricted, with an apparent diffusion coefficient of 1.0+/-0.4 x 10(-4) microm(2)/s. In contrast, vesicles located in the interior moved much more freely and escaped from the visual confocal plane. Lysotracker labeling was more appropriate to study the movement of the faster moving vesicles, whose diffusion coefficient was five times higher. Using this type of labeling we confirmed the restriction on cortical movement and showed a clear relationship between vesicle mobility and the kinetics of cytoskeletal movement on both sides of the cortical cytoskeleton. This relationship was further emphasized by studying cytoskeletal organization and kinetics. Indeed, an estimate of the size of the cytoskeletal polygonal cages present in the cortical region and in the cell interior agreed well with the calculation of the theoretical radius of the cages imprisoning vesicle movement. Therefore, these data suggest that the structure and kinetics of the cytoskeleton governs vesicle movements in different regions of chromaffin cells.
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Actinas/metabolismo , Células Cromafins/fisiologia , Grânulos Cromafim/fisiologia , Vesículas Secretórias/fisiologia , Aminas/metabolismo , Análise de Variância , Animais , Bovinos , Células Cromafins/ultraestrutura , Grânulos Cromafim/ultraestrutura , Simulação por Computador , Microscopia Confocal/métodos , Microscopia Eletrônica de Varredura/métodos , Modelos Biológicos , Vesículas Secretórias/ultraestrutura , Fatores de TempoRESUMO
Paget's disease is a chronic osteopathy of unknown origin affecting principally the long bones of body. One of those cases is here reported localized in this area, with favorable answer to medical treatment. Perusal of literature about this subject.
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Maxila/patologia , Osteíte Deformante/patologia , Idoso , Feminino , Humanos , Maxila/diagnóstico por imagem , Osteíte Deformante/diagnóstico por imagem , RadiografiaRESUMO
Obesity is a main risk factor in the development of diseases, which are causes of death in elderly population. Socio-economic characteristics had an impact in the prevalence of obesity. The purpose of this study was to estimate the prevalence of obesity in elderly Mexican women living in a marginal community and compare their results with those of women of urban and rural areas in Mexico. The study has a cross sectional design. Standardised nutritionist carried out the measurements. The international techniques recommended were used to measure weight and height. To estimate the proportion of overweight and obesity, the body mass index (BMI) was used following the WHO categories. A total of 249 elderly women were examined. The mean age was 71.6 (sd 7.8). No difference in age was found in the three communities visited (p>0.05). The mean BMI in the urban women was 26.7 (sd 4.6), in the rural 24.5 (sd 3.9), and in the marginal group 28.6 (sd 5.5) (p<0.0001). The proportion of overweight and obese women was in the urban group 60.7%, in the rural 36.2%, and in the marginal women 76.5% (p<0.001). The results of this study indicated the presence of a high prevalence of overweight and obesity in elderly women of urban and particularly in the marginal areas. Marginality seams to be a risk marker of obesity in elderly women in Mexico. Intervention programs aimed to decrease the prevalence of obesity and improve nutritional condition in this group are urgent.
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Envelhecimento/fisiologia , Obesidade/epidemiologia , Idoso , Estatura , Índice de Massa Corporal , Peso Corporal , Estudos Transversais , Feminino , Nível de Saúde , Humanos , México/epidemiologia , Prevalência , Saúde da População Rural , Saúde da População UrbanaRESUMO
We have taken advantage of the differences between the preferential localization of secretion in the terminals of neurite-emitting bovine chromaffin cells in contrast with the random distribution secretion in spherical cells to study the possible molecular factors determining such localization by using immunofluorescence and confocal microscopy techniques. By analyzing the distribution of dopamine beta-hydroxylase present in the membrane of chromaffin granules, we found that vesicles migrate and accumulate in dense packages in the terminals of neurite processes. Neither members of the fusion core complex such as SNAP-25, nor nicotinic receptors are preferentially located in the terminals as would be expected from elements defining sites of release, thereby suggesting the presence of additional factors. Interestingly, we observed a preferential distribution of the P/Q subtype of Ca2+ channels in these neurite terminals and co-localization with vesicles present in these structures, in sharp contrast with the overall distribution of the L subtype channels. Using the same immunofluorescence techniques we were unable to detect N-type calcium channels. In addition, omega-agatoxin IVA was able to block 70% of the exocytotic release occurring into the neurites, whereas L-type blockers had a weak effect. Taken together our results strongly indicate that the co-localization of vesicles and clusters of P/Q Ca2+ channels may explain the precise localization of exocytotic sites in the terminals of neurite-emitting chromaffin cells, whereas the distribution of secretory sites in round cells may arise from the random presence of these factors as indicated by their partial co-localization.
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Canais de Cálcio Tipo N/análise , Células Cromafins/metabolismo , Vesículas Citoplasmáticas/química , Exocitose/fisiologia , Neuritos/fisiologia , Proteínas de Transporte Vesicular , Glândulas Suprarrenais/citologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Catecolaminas/metabolismo , Bovinos , Células Cultivadas , Células Cromafins/química , Células Cromafins/citologia , Exocitose/efeitos dos fármacos , Imuno-Histoquímica , Proteínas de Membrana/análise , Neuritos/química , Terminações Pré-Sinápticas/química , Receptores Nicotínicos/análise , Proteínas SNARE , Vesículas Secretórias/química , ômega-Agatoxina IVA/farmacologiaRESUMO
Amperometry was used to study secretory kinetics of single bovine chromaffin cells stimulated by transient depolarizations at different temperatures. The initial rate of release was moderately enhanced when the temperature was raised from 18 to 22 and 37 degrees C. Secretion increased drastically at a later period, 5-10 s after the initiation of stimulus. Interestingly, incubation of the cells with phorbol 12-myristate 13-acetate (PMA) clearly enhanced fast secretory components. In addition, the rate of secretion of the slower component recruited by prolonged depolarizations (t > 30 s) was unaffected at the range of temperatures normally used in secretory experiments (22-37 degrees C). A 'counting events' analysis of secretion, which avoids the influence of event charge changes, showed specific increases in a population of vesicles fusing between 7 and 12 s over the same range of temperatures, and a marked increase in vesicles fusing during the initial phase (1-5 s), of PMA-treated cell secretion. An analysis of temperature influence on transient components released by high sucrose, the secretion elicited by cell permeabilization with digitonin, and studies of the individual characteristics of amperometric events, allow us to conclude that an increase in the size of a secondary-released vesicle population is the main factor contributing to temperature-dependent enhancement of secretion, in clear contrast to the enhancement of fast releasable pools caused by phorbol esters.
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Carcinógenos/farmacologia , Células Cromafins/metabolismo , Exocitose/efeitos dos fármacos , Temperatura , Acetato de Tetradecanoilforbol/farmacologia , Animais , Cálcio/metabolismo , Bovinos , Células Cultivadas , Células Cromafins/citologia , Células Cromafins/efeitos dos fármacos , Exocitose/fisiologia , Soluções Hipertônicas/farmacologia , Cinética , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Potássio/farmacologia , Estimulação Química , Vesículas Sinápticas/metabolismoRESUMO
Adrenal chromaffin cells were used to test the role of the peripheral cytoskeleton of F-actin in controlling different vesicle pools. Phorbol 12-myristate 13-acetate and calyculin A, two substances affecting phosphorylation-dephosphorylation cycles, produced different degrees of F-actin reorganization, inducing the partial and the almost total disassembly of this structure, respectively, as visualized using rhodamine-phalloidin staining. Consequently, electron microscopy studies revealed the higher efficiency of calyculin-A over phorbol 12-myristate 13-acetate in promoting vesicle access to the plasmalemma boundary. Surprisingly, only the phorbol ester enhanced fast kinetics and the population of rapidly releasable vesicle pools as studied by single-cell amperometry, whereas both agents, as well as the F-actin severing compound, Latrunculin A, promoted an increase in the population of vesicles recruited in response to prolonged or repetitive stimulations. Taken together, our data support the notion that the F-actin peripheral barrier controls primary granule recruitment from reserve vesicle pools, whereas the phorbol ester effect on the rapidly releasable pools might be related to the alteration of late secretory stage through protein kinase C-dependent phosphorylation of an unidentified target.
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Actinas/metabolismo , Células Cromafins/metabolismo , Grânulos Citoplasmáticos/metabolismo , Citoesqueleto/metabolismo , Glândulas Suprarrenais/citologia , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Carcinógenos/farmacologia , Bovinos , Membrana Celular/metabolismo , Células Cromafins/efeitos dos fármacos , Células Cromafins/ultraestrutura , Citoesqueleto/ultraestrutura , Eletrofisiologia , Inibidores Enzimáticos/farmacologia , Exocitose/fisiologia , Toxinas Marinhas , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Microscopia Eletrônica , Oxazóis/farmacologia , Fosforilação , Acetato de Tetradecanoilforbol/farmacologia , Tiazóis/farmacologia , TiazolidinasRESUMO
Amperometry in chromaffin cells expressing green fluorescent protein (GFP) fused to synaptosome-associated protein of 25 kDa (SNAP-25) have been used to test the involvement of single amino acids in exocytotic function, overcoming some of the limitations of studies based on Botulinum neurotoxin cleavage, as this occurs at defined sites of the protein. Constructs containing either the whole SNAP-25 polypeptide or several deleted forms lacking its C-terminal domain were heavily overexpressed in transfected cells. All GFP-fusions were located in both the cytoplasm and the plasma membrane. Although a construct containing complete SNAP-25 sustained normal secretion, removal of four or more amino acids of its C terminus greatly altered the overall rate and extent of exocytosis. Further mutational analysis proved that Leu203, the fourth residue from the C terminus, is critical for secretion. Kinetics of single granule fusions from cells expressing truncated forms showed slow onset and decay times when compared with control cells expressing full SNAP-25. Thus, these data provide direct evidence for the involvement of a specific residue of SNAP-25 in exocytosis and show that overexpression of GFP-SNAP contructs combined with single vesicle fusion measurements constitutes a powerful approach to dissect the structural elements playing a role in individual steps of the exocytotic cascade.
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Células Cromafins/fisiologia , Proteínas de Membrana , Proteínas do Tecido Nervoso/fisiologia , Animais , Bovinos , Células Cultivadas , Análise Mutacional de DNA , Exocitose/fisiologia , Proteínas do Tecido Nervoso/química , Análise de Sequência , Deleção de Sequência , Relação Estrutura-Atividade , Proteína 25 Associada a SinaptossomaRESUMO
Lipomatosis of the tongue is an extremely rare condition. To date, only 5 cases have been reported in the literature. An additional example, confirmed by biopsy, is presented. This appears to represent only the second instance of a nonoriental person who has been described with this condition.
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Lipomatose/patologia , Doenças da Língua/patologia , Idoso , Humanos , MasculinoRESUMO
Truncation of the C-terminal domain of the synaptosomal associated protein of 25 kDa (SNAP-25) by botulinum neurotoxin A (BoNT A) has been shown to block neuroendocrine cell secretion. It is unclear, however, if toxin mechanism involved the affection of a single or more events of the exocytotic cascade. BoNT A induced changes in both the degree of inhibition and the kinetics of catecholamine secretion from populations of cultured bovine chromaffin cells. Ca2+-dependent secretion from digitonin-permeabilized cells showed partial inhibition associated with the alteration of a slow secretory phase at different toxin concentrations. In contrast, in intact cells stimulated by depolarization, cell treatment with low concentrations (1 nM) of the toxin affected the late phase of secretion, whereas 100 nM BoNT A-poisoned cells showed an alteration even of fast components. The high degree of inhibition associated with fast secretory component alteration was dependent on Ca2+ entry through the Ca2+ channels, as it was absent from cells permeated with the A23187 Ca2+ ionophore. Vesicle pools implicated in the effect of BoNT A on the secretory response from single cells were identified using amperometry. These studies supported the macroscopic view by showing that secretion from BoNT A-treated permeabilized cells presented specific inhibition of late vesicle fusions. Intact cells showed alterations in the late vesicle pool (t1/2 = 39 s) recruited during prolonged or repetitive KCI depolarizations using 1 nM BoNT A-treated cells as well as in an intermediate kinetic pool (t1/2 = 18 s) at higher toxin concentrations (100 nM). The faster resolved component (t1/2 = 8 s) or the membrane fusion event itself were not affected. Our results demonstrate that removal of the last nine C-terminal amino acids of SNAP-25 by BoNT A has a specific effect on two different and distal secretory stages in chromaffin cells.