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1.
J Allied Health ; 52(2): 89-96, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37269026

RESUMO

BACKGROUND: An urgent educational need is to examine the current gaps in cultural competence/humility, diversity, equity, inclusion, and accessibility (DEIA) that may significantly affect the teaching and learning environments among students/faculty. This mixed-methods study examined the current level of cultural competemility and perceptions of diversity, equity, and inclusion (DEI)-related challenges and recommendations among students/faculty of health professions. METHODS: Students and faculty completed a survey including the Inventory for Assessing the Process of Cultural Competemility Among Healthcare Professionals (IAPCC-HCP©) and open-ended questions on their DEI perceptions and needs. Data were analyzed via descriptive statistics and independent t-tests. Qualitative data were coded using thematic content analysis. OUTCOMES: A total of 100 participants (64 students, 38 faculty) completed the survey. The majority identified as Caucasian or non-Hispanic White and female, and were satisfied with DEIA-related school-level initiatives and familiar with how to use pronouns to reflect all genders. Compared to students, faculty scored slightly higher, although not significantly, in five of six domains, including Cultural Humility, Cultural Awareness, Culture Skill, Cultural Encounters and Cultural Desire. Participants shared their need to address: 1) DEIA gaps in knowledge and Schools of Health Professions curriculum; 2) involvement of students; 3) racism, biases, and discrimination; and 4) recognition of underrepresented groups. Training needs were in the areas of 1) DEIA assessment and training for students and faculty; 2) DEIA school activities; 3) DEIA-informed policies; and 4) modifications to clinical education. CONCLUSION: The faculty more than students expressed the need to enhance their DEI and cultural knowledge. Our findings can guide further development of educational activities and school-level DEI initiatives in schools of health professions.


Assuntos
Competência Cultural , Diversidade, Equidade, Inclusão , Humanos , Masculino , Feminino , Currículo , Estudantes , Docentes
6.
PLoS One ; 15(12): e0242590, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33270660

RESUMO

Respiratory distress due to preterm birth is a significant cause of death in low-resource settings. The introduction of continuous positive airway pressure (CPAP) systems to treat respiratory distress significantly reduced mortality in high-resource settings, but CPAP was only recently introduced in low-resource settings due to cost and infrastructure limitations. We evaluated pressure stability and imposed work of breathing (iWOB) of five CPAP systems used in low resource settings: the Fisher and Paykel bubble CPAP, the Diamedica baby CPAP, the Medijet nCPAP generator, and the first (2015) and second (2017) generation commercially available Pumani CPAPs. Pressure changes due to fresh gas flow were evaluated for each system by examining the relationship between flow and pressure at the patient interface for four pressures generated at the bottle (0, 3, 5, and 7 cm H2O); for the Medijet nCPAP generator, no bottle was used. The slope of the resulting relationship was used to calculate system resistance. Poiseuille's law of resistance was used to investigate significant contributors to resistance. Resistance ranged from 0.05 to 1.40 [Formula: see text]; three CPAP devices had resistances < 0.4 [Formula: see text]: the Fisher and Paykel system, the Diamedica system, and the second generation Pumani bubble CPAP. The other two systems, the Medijet nCPAP generator and the first generation Pumani bCPAP, had resistances >1.0 [Formula: see text]. Imposed WOB was measured using an ASL5000 test lung to simulate the breath cycle for an infant (5.5 kg), a term neonate (4.0 kg), and a preterm neonate (2.5 kg). Imposed WOB ranged from 1.4 to 39.5 mJ/breath across all systems and simulated infant sizes. Changes in pressure generated by fresh gas flow, resistance, and iWOB differ between the five systems evaluated under ideal laboratory conditions. The available literature does not indicate that these differences affect clinical outcomes.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas , Recursos em Saúde , Trabalho Respiratório , Gases , Humanos , Pressão , Reologia
7.
Shock ; 54(6): 774-782, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32590700

RESUMO

The severity of burn and smoke inhalation-induced acute lung injury (BSI-ALI) is associated with alveolar and interstitial edema, bronchospasm, and airway mucosal hyperemia. Previously, we have reported beneficial effects of epinephrine nebulization on BSI-ALI. However, the underlying mechanisms of salutary effects of nebulized epinephrine remain unclear. The present study compared the effects of epinephrine, phenylephrine, and albuterol on a model of BSI-ALI. We tested the hypothesis that both α1- and ß2-agonist effects are required for ameliorating more efficiently the BSI-ALI. Forty percent of total body surface area, 3rd-degree cutaneous burn, and 48-breaths of cotton smoke inhalation were induced to 46 female Merino sheep. Postinjury, sheep were mechanically ventilated and cardiopulmonary hemodynamics were monitored for 48 h. Sheep were allocated into groups: control, n = 17; epinephrine, n = 11; phenylephrine, n = 6; and albuterol, n = 12. The drug nebulization began 1 h postinjury and was repeated every 4 h thereafter. In the results, epinephrine group significantly improved oxygenation compared to other groups, and significantly reduced pulmonary vascular permeability index, lung wet-to-dry weight ratio, and lung tissue growth factor-ß1 level compared with albuterol and control groups. Epinephrine and phenylephrine groups significantly reduced trachea wet-to-dry weight ratio and lung vascular endothelial growth factor-A level compared with control group. Histopathologically, epinephrine group significantly reduced lung severity scores and preserved vascular endothelial-cadherin level in pulmonary arteries. In conclusion, the results of our studies suggest that nebulized epinephrine more effectively ameliorated the severity of BSI-ALI than albuterol or phenylephrine, possibly by its combined α1- and ß2-agonist properties.


Assuntos
Lesão Pulmonar Aguda , Albuterol/farmacologia , Queimaduras , Epinefrina/farmacologia , Fenilefrina/farmacologia , Lesão por Inalação de Fumaça , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Administração por Inalação , Animais , Queimaduras/tratamento farmacológico , Queimaduras/metabolismo , Queimaduras/patologia , Feminino , Nebulizadores e Vaporizadores , Ovinos , Lesão por Inalação de Fumaça/tratamento farmacológico , Lesão por Inalação de Fumaça/metabolismo , Lesão por Inalação de Fumaça/patologia
8.
Biochem Biophys Res Commun ; 526(1): 141-146, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32199614

RESUMO

Smoke inhalation injury (SII) affects more than 50,000 people annually causing carbon monoxide (CO) poisoning. Although the increased blood level of carboxyhemoglobin (CO-Hb) is frequently used to confirm the diagnosis of SII, knowledge of its elimination in the acute phase is still limited. The aim of this study is to determine CO-Hb elimination rates and their differences in arterial (aCO-Hb) and mixed-venous (vCO-Hb) blood following severe SII in a clinically relevant ovine model. Forty-three chronically instrumented female sheep were subjected to SII (12 breaths, 4 sets) through tracheostomy tube under anesthesia and analgesia. After the SII, sheep were awakened and placed on a mechanical ventilator (FiO2 = 1.0, tidal volume 12 mL/kg, and PEEP = 5cmH2O) and monitored. Arterial and mixed-venous blood samples were withdrawn simultaneously for blood gas analysis at various time points to determine CO-HB half-lifetime and an elimination curve. The mean of highest aCO-Hb level during SII was 70.8 ± 13.9%. The aCO-Hb elimination curve showed an approximated exponential decay during the first 60 min. Per mixed linear regression model analysis, aCO-Hb significantly (p < 0.001) declined (4.3%/minute) with a decay constant lambda of 0.044. With this lambda, mean lifetime and half-lifetime of aCO-Hb were 22.7 and 15.7 min, respectively. The aCO-Hb was significantly lower compared to vCO-Hb at all-time points (0-180 min). To our knowledge, this is the first report describing CO-Hb elimination curve in the acute phase after severe SII in the clinically relevant ovine model. Our data shows that CO-Hb is decreasing in linear manner with supportive mechanical ventilation (0-60 min). The results may help to understand CO-Hb elimination curve in the acute phase and improvement of pre-hospital and initial clinical care in patients with CO poisoning.


Assuntos
Artérias/patologia , Intoxicação por Monóxido de Carbono/sangue , Carboxihemoglobina/metabolismo , Lesão por Inalação de Fumaça/sangue , Veias/patologia , Doença Aguda , Animais , Artérias/fisiopatologia , Intoxicação por Monóxido de Carbono/fisiopatologia , Modelos Animais de Doenças , Feminino , Meia-Vida , Hemodinâmica , Ovinos , Lesão por Inalação de Fumaça/fisiopatologia , Veias/fisiopatologia
9.
Med. lab ; 24(2): 93-109, 2020.
Artigo em Espanhol | LILACS, COLNAL | ID: biblio-1097051

RESUMO

Los desórdenes de la glándula tiroides son comunes y pueden afectar hasta el 10% de la población en general. En muchas ocasiones los síntomas pueden ser inespecíficos, por lo que el médico en busca de un trastorno tiroideo debe llegar a un diagnóstico funcional y anatómico. Las mediciones séricas de las hormonas tiroideas confirman si hay un exceso, un déficit o si las concentraciones son normales. Para ello, se requiere un rango de referencia de la población local, y específicamente por grupos de edad, para una correcta interpretación de las pruebas de función tiroidea. Las hormonas tiroideas juegan un papel fundamental en el sistema endocrino, controlan el metabolismo general del cuerpo, el desarrollo neural, el crecimiento normal y la maduración de los huesos, así como funciones cardiovasculares y renales, entre otras. En esta revisión se pretende dar una aproximación a las pruebas tiroideas más relevantes, partiendo de la biosíntesis y secreción de las hormonas tiroideas, hasta llegar al abordaje para un diagnóstico inicial del paciente con trastorno tiroideo, mencionando los aspectos más importantes de los diferentes patrones tiroideos. El tratamiento detallado de cada uno de ellos, supera las expectativas de esta revisión


Thyroid gland disorders are common and can affect up to 10% of the general population. In many cases the symptoms can be nonspecific, so the physician in search for a thyroid disorder should reach a functional and anatomical diagnosis. Serum measurements of thyroid hormones confirm if there is an excess, a deficit, or if concentrations are normal. For this, reference ranges of the local population, and specifically by age groups, are required for a correct interpretation of thyroid function tests. Thyroid hormones play a fundamental role in the endocrine system, control of the general metabolism of the body, neural development, normal growth and maturation of bones, as well as in cardiovascular and renal functions, among others. In this review, the most relevant thyroid tests will be described, starting with the biosynthesis and secretion of thyroid hormones, and continuing with an approach to reach an initial diagnosis. Finally, the most important aspects of the different thyroid patterns will be mentioned. It is beyond the scope of this review, to describe the treatment for thyroid disorders.


Assuntos
Humanos , Doenças da Glândula Tireoide , Testes de Função Tireóidea , Hormônios Tireóideos , Tiroxina , Tri-Iodotironina , Tireotropina
10.
Respir Care ; 64(8): 931-936, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30914490

RESUMO

BACKGROUND: COPD is now included in Medicare's hospital readmission reduction program. Hospitals with excessive risk-adjusted 30-d readmission rates receive financial penalties. Race/ethnicity is not included in the risk-adjustment models. We examined whether race/ethnicity was independently associated with readmission after controlling for clinical factors and other demographic variables. METHODS: We used the 100% Medicare in-patient (Part A) files to identify patients hospitalized with COPD (MS-DRG codes 190, 191, 192) who were discharged between January 1, 2013, and September 13, 2014. The outcome measure was an unplanned readmission within 30 d of hospital discharge. We used generalized linear mixed models to test the independent effects of race/ethnicity on 30-d readmission. RESULTS: The sample included 298,706 Medicare beneficiaries hospitalized for COPD: 87% white, 8% African-American, and 5% Hispanic. Mean age was 77.7 ± 7.7 y. Overall, 17.3% of subjects experienced an unplanned readmission. Whites (17.4%) and African-Americans (17.7%) had significantly higher unadjusted rates than Hispanics, and Hispanics demonstrated the lowest readmission rate (16.3%). The minority groups generally displayed higher-risk clinical profiles. After controlling for those differences, the multivariable model suggested a benefit for both minority groups in terms of readmission risk. The adjusted readmission rates for whites, African-Americans, and Hispanics were 16.6%, 15.9%, and 14.6%, respectively. CONCLUSIONS: Racial/ethnic disparities in observed readmission rates may be largely explained by the more severe clinical profiles of minority populations. Controlling for known clinical risk factors effectively mediates the relationship between race/ethnicity and readmission.


Assuntos
Negro ou Afro-Americano/estatística & dados numéricos , Hispânico ou Latino/estatística & dados numéricos , Grupos Minoritários/estatística & dados numéricos , Readmissão do Paciente/estatística & dados numéricos , Doença Pulmonar Obstrutiva Crônica/etnologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Hospitais/estatística & dados numéricos , Humanos , Modelos Lineares , Masculino , Medicare , Fatores de Risco , Estados Unidos , População Branca/estatística & dados numéricos
11.
Shock ; 52(5): e92-e99, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30499879

RESUMO

Vascular hypo-responsiveness to vasopressors during septic shock is a challenging problem. This study is to test the hypothesis that reactive nitrogen species (RNS), such as peroxynitrite, are major contributing factors to vascular hypo-responsiveness in septic shock. We hypothesized that adjunct therapy with peroxynitrite decomposition catalyst (PDC) would reduce norepinephrine requirements in sepsis resuscitation. Fourteen female Merino sheep were subjected to a "two-hit" injury (smoke inhalation and endobronchial instillation of live methicillin-resistant Staphylococcus aureus [1.6-2.5 × 10 CFUs]). The animals were randomly allocated to control: injured, fluid resuscitated, and titrated norepinephrine, n = 7; or PDC: injured, fluid resuscitated, titrated norepinephrine, and treated with PDC, n = 7. One-hour postinjury, an intravenous injection of PDC (0.1 mg/kg) was followed by a continuous infusion (0.04 mg/kg/h). Titration of norepinephrine started at 0.05 mcg/kg/min based on their mean arterial pressure. All animals were mechanically ventilated and monitored in the conscious state for 24 h. The mean arterial pressure was well maintained in the PDC with significantly less norepinephrine requirement from 7 to 23 h after injury compared with control. Total norepinephrine dose, the highest norepinephrine rate, and time on norepinephrine support were also significantly lower in PDC. Modified sheep organ failure assessment scores at 6 to 18 h postinjury were significantly lower in PDC compared with control. PDC improved survival rate at 24 h (71.4% vs. 28.6%). PDC treatment had no adverse effects. In conclusion, the modulation of RNS may be considered an effective adjunct therapy for septic shock, in the case of hypo-responsiveness to norepinephrine.


Assuntos
Staphylococcus aureus Resistente à Meticilina/metabolismo , Norepinefrina/farmacologia , Ácido Peroxinitroso/sangue , Doenças dos Ovinos , Choque Séptico , Infecções Estafilocócicas , Animais , Feminino , Ovinos , Doenças dos Ovinos/sangue , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/microbiologia , Choque Séptico/sangue , Choque Séptico/tratamento farmacológico , Choque Séptico/microbiologia , Choque Séptico/veterinária , Infecções Estafilocócicas/sangue , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/veterinária
12.
Food Sci Technol Int ; 24(8): 705-712, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30060685

RESUMO

Edible films are among the most promising fields in food science over the last decade due to their versatility (they can be made from a wide array of materials) and because they can be used as carriers of different active substances, like antioxidants, antimicrobial agents, and essential oils from plants. In the case of the essential oils, their inclusion in edible films is limited by their low water solubility. Nanoemulsions are thermodynamically stable and transparent systems that can be used as a way of incorporating essential oils into edible film matrices. In this paper, we developed lemongrass and rosemary essential oil nanoemulsions by using a low-energy method, observing the effect of the surfactant/oil ratio in their physicochemical properties. Then we studied the effect of the nanoemulsions concentration incorporated into banana starch edible films. We observed that essential oils' nanoemulsions have a plasticizing effect increasing the film's water vapor permeability, transparency, and elongation at break, while the hydrophobic nature of the essential oils lead to a decrease in their water solubility.


Assuntos
Cymbopogon/química , Emulsões , Embalagem de Alimentos/métodos , Musa/química , Óleos Voláteis , Rosmarinus/química , Amido/química , Anti-Infecciosos , Interações Hidrofóbicas e Hidrofílicas , Nanoestruturas , Permeabilidade , Plastificantes , Solubilidade , Vapor
13.
Surg Clin North Am ; 95(4): 751-66, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26210968

RESUMO

Simulation-based training (SBT) is a powerful educational tool permitting the acquisition of surgical knowledge, skills, and attitudes at both the individual- and team-based level in a safe, nonthreatening learning environment at no risk to a patient. Interprofessional education (IPE), in which participants from 2 or more health or social care professions learn interactively, can help improve patient care through the promotion of efficient coordination, dissemination of advances in care across specialties and professions, and optimization of individual- and team-based function. Nonetheless, conducting SBT IPE sessions poses several tactical and strategic challenges that must be effectively overcome to reap IPE's benefits.


Assuntos
Simulação por Computador , Comportamento Cooperativo , Cirurgia Geral/educação , Comunicação Interdisciplinar , Manequins , Simulação de Paciente , Competência Clínica , Currículo , Humanos , Equipe de Assistência ao Paciente , Conselhos de Especialidade Profissional
15.
J Biol Chem ; 283(19): 12777-88, 2008 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-18319254

RESUMO

The SLC4A10 gene product, commonly known as NCBE, is highly expressed in rodent brain and has been characterized by others as a Na(+)-driven Cl-HCO(3) exchanger. However, some of the earlier data are not consistent with Na(+)-driven Cl-HCO(3) exchange activity. In the present study, northern blot analysis showed that, also in humans, NCBE transcripts are predominantly expressed in brain. In some human NCBE transcripts, splice cassettes A and/or B, originally reported in rats and mice, are spliced out. In brain cDNA, we found evidence of a unique partial splice of cassette B that is predicted to produce an NCBE protein with a novel C terminus containing a protein kinase C phosphorylation site. We used pH-sensitive microelectrodes to study the molecular physiology of human NCBE expressed in Xenopus oocytes. In agreement with others we found that NCBE mediates the 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid-sensitive, Na(+)-dependent transport of HCO(3)(-). For the first time, we demonstrated that this transport process is electroneutral. Using Cl(-)-sensitive microelectrodes positioned at the oocyte surface, we found that, unlike both human and squid Na(+)-driven Cl-HCO(3) exchangers, human NCBE does not normally couple the net influx of HCO(3)(-) to a net efflux of Cl(-). Moreover we found that that the (36)Cl efflux from NCBE-expressing oocytes, interpreted by others to be coupled to the influx of Na(+) and HCO(3)(-), actually represents a CO(2)/HCO(3)(-)-stimulated Cl(-) self-exchange not coupled to either Na(+) or net HCO(3)(-) transport. We propose to rename NCBE as the second electroneutral Na/HCO(3) cotransporter, NBCn2.


Assuntos
Bicarbonatos/metabolismo , Cloretos/metabolismo , Neurônios/metabolismo , Simportadores de Sódio-Bicarbonato/metabolismo , Sódio/metabolismo , Animais , Bicarbonatos/química , Transporte Biológico , Cloretos/química , Clonagem Molecular , Eletrofisiologia , Feminino , Humanos , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Oócitos , Técnicas de Patch-Clamp , RNA Mensageiro/genética , Sódio/química , Simportadores de Sódio-Bicarbonato/genética , Xenopus laevis
16.
J Cell Physiol ; 201(2): 190-200, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15334654

RESUMO

Angiogenesis requires invasion of extracellular matrix (ECM) proteins by endothelial cells and occurs in hypoxic and acidic environments that are not conducive for cell growth and survival. We hypothesize that angiogenic cells must exhibit a unique system to regulate their cytosolic pH in order to cope with these harsh conditions. The plasmalemmal vacuolar type H(+)-ATPase (pmV-ATPase) is used by cells exhibiting an invasive phenotype. Because angiogenesis is impaired in diabetes, we hypothesized that pmV-ATPase is decreased in microvascular endothelial cells from diabetic rats. The in vitro angiogenesis assays demonstrated that endothelial cells were unable to form capillary-like structures in diabetes. The proton fluxes were slower in cells from diabetic than normal model, regardless of the presence or absence of Na(+) and HCO(3) (-) and were suppressed by V-H(+)-ATPase inhibitors. Immunocytochemical data revealed that pmV-ATPases were inconspicuous at the plasma membrane of cells from diabetic whereas in normal cells were prominent. The pmV-ATPase activity was lower in cells from diabetic than normal models. Inhibition of V-H(+)-ATPase suppresses invasion/migration of normal cells, but have minor effects in cells from diabetic models. These novel observations suggest that the angiogenic abnormalities in diabetes involve a decrease in pmV-ATPase in microvascular endothelial cells.


Assuntos
Membrana Celular/metabolismo , Diabetes Mellitus/metabolismo , Células Endoteliais/metabolismo , Neovascularização Fisiológica/fisiologia , ATPases Vacuolares Próton-Translocadoras/metabolismo , Animais , Células Cultivadas , Citoplasma/química , Angiopatias Diabéticas/etiologia , Modelos Animais de Doenças , Concentração de Íons de Hidrogênio , Imuno-Histoquímica , Ratos , Ratos Endogâmicos BB
17.
Biochem Biophys Res Commun ; 320(4): 1123-32, 2004 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-15249206

RESUMO

The lung endothelium layer is exposed to continuous CO(2) transit which exposes the endothelium to a substantial acid load that could be detrimental to cell function. The Na(+)/H(+) exchanger and HCO(3)(-)-dependent H(+)-transporting mechanisms regulate intracellular pH (pH(cyt)) in most cells. Cells that cope with high acid loads might require additional primary energy-dependent mechanisms. V-H(+)-ATPases localized at the plasma membranes (pmV-ATPases) have emerged as a novel pH regulatory system. We hypothesized that human lung microvascular endothelial (HLMVE) cells use pmV-ATPases, in addition to Na(+)/H(+) exchanger and HCO(3)(-)-based H(+)-transporting mechanisms, to maintain pH(cyt) homeostasis. Immunocytochemical studies revealed V-H(+)-ATPase at the plasma membrane, in addition to the predicted distribution in vacuolar compartments. Acid-loaded HLMVE cells exhibited proton fluxes in the absence of Na(+) and HCO(3)(-) that were similar to those observed in the presence of either Na(+), or Na(+) and HCO(3)(-). The Na(+)- and HCO(3)(-)-independent pH(cyt) recovery was inhibited by bafilomycin A(1), a V-H(+)-ATPase inhibitor. These studies show a Na(+)- and HCO(3)(-)-independent pH(cyt) regulatory mechanism in HLMVE cells that is mediated by pmV-ATPases.


Assuntos
Membrana Celular/metabolismo , Endotélio Vascular/metabolismo , Líquido Intracelular/metabolismo , Pulmão/metabolismo , Microcirculação/metabolismo , ATPases Vacuolares Próton-Translocadoras/metabolismo , Membrana Celular/química , Células Cultivadas , Endotélio Vascular/química , Endotélio Vascular/citologia , Humanos , Concentração de Íons de Hidrogênio , Líquido Intracelular/química , Pulmão/irrigação sanguínea , Pulmão/química , Pulmão/citologia , Microcirculação/química , Microcirculação/citologia , ATPases Vacuolares Próton-Translocadoras/química
18.
Am J Physiol Renal Physiol ; 284(6): F1199-206, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12604466

RESUMO

The electrogenic Na(+)-HCO(3)(-) cotransporter NBCe1 is important for the regulation of intracellular pH (pH(i)) and for epithelial HCO(3)(-) transport in many tissues, including kidney, pancreas, and brain. In the present study, we investigate glycosylation sites in NBCe1. Treatment of rat kidney membrane extracts with peptide N-glycosidase F (PNGase F) shifted the apparent molecular weight (MW) of NBCe1 from 130 to 116, the MW predicted from the deduced amino acid sequence. Treatment with endoglycosidase F(2) or H or O-glycosidase did not affect the MW of NBCe1. Lectin-binding studies, together with the enzyme data, suggest that the N-linked carbohydrates are of tri- or tetra-antennary type. To localize glycosylation sites, we individually mutated the seven consensus N-glycosylation sites by replacing asparagine (N) with glutamine (Q) and assessing mutant transporters in Xenopus laevis oocytes. Immunoblotting of oocyte membrane extracts treated with PNGase F indicates that NBCe1 is normally glycosylated at N597 and N617 (both on the third extracellular loop). However, N592 (on the same loop) is glycosylated when the other two sites are mutated. The triple mutant (N592Q/N597Q/N617Q) is completely unglycosylated but, based on microelectrode measurements of membrane potential and pH(i) in oocytes, preserves the Na(+) and HCO(3)(-) dependence and electrogenicity of wild-type NBCe1.


Assuntos
Rim/metabolismo , Simportadores de Sódio-Bicarbonato/metabolismo , Amidoidrolases/química , Substituição de Aminoácidos/fisiologia , Animais , Membrana Celular/enzimologia , Membrana Celular/metabolismo , Glicosilação , Histocitoquímica , Concentração de Íons de Hidrogênio , Immunoblotting , Lectinas , Microeletrodos , Peso Molecular , Mutagênese Sítio-Dirigida , Mutação/genética , Mutação/fisiologia , Oligossacarídeos/metabolismo , Oócitos/metabolismo , Peptídeo-N4-(N-acetil-beta-glucosaminil) Asparagina Amidase , Coelhos , Ratos , Ratos Sprague-Dawley , Simportadores de Sódio-Bicarbonato/química , Simportadores de Sódio-Bicarbonato/fisiologia , Especificidade da Espécie , Xenopus laevis
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