RESUMO
Type 2 diabetes mellitus (T2DM) is a fast progressing disease reaching pandemic proportions. T2DM is specifically harmful because of its severe secondary complications. In the course of the disease, most patients require treatment with oral antidiabetic drugs (OADs), for which a relatively large number of different options are available. The growing number of individuals affected by T2DM as well as marked interindividual differences in the response to treatment call for individualized therapeutic regimens that can maximize treatment efficacy and thus reduce side effects and costs. A large number of genetic polymorphisms have been described affecting the response to treatment with OADs; in this review, we summarize the most recent advances in this area of research. Extensive evidence exists for polymorphisms affecting pharmacokinetics and pharmacodynamics of biguanides and sulfonylureas. Data on incretin-based medications as well as the new class of sodium/glucose cotransporter 2 (SGLT2) inhibitors are just starting to emerge. With diabetes being a known comorbidity of several psychiatric disorders, we also review genetic polymorphisms possibly responsible for a common treatment response in both conditions. For all drug classes reviewed here, large prospective trials are necessary in order to consolidate the existing evidence and derive treatment schemes based on individual genetic traits.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/administração & dosagem , Incretinas/administração & dosagem , Variantes Farmacogenômicos , Polimorfismo Genético , Administração Oral , Comorbidade , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/genética , Genótipo , Humanos , Hipoglicemiantes/efeitos adversos , Hipoglicemiantes/farmacocinética , Incretinas/efeitos adversos , Incretinas/farmacocinética , Transtornos Mentais/epidemiologia , Transtornos Mentais/genética , Farmacogenética , Fenótipo , Resultado do TratamentoRESUMO
Recent data using MHC/peptide tetramers and dimers suggests that the T cell coreceptors, CD4 and CD8, although important for T cell activation, do not play a direct role in facilitating T cell receptor (TCR) binding to multivalent MHC/peptide ligands. Instead, a current model proposes that coreceptors are recruited only after a stable TCR-MHC/peptide complex has already formed and signaled. In contrast, we show using multimeric class I MHC/peptide ligands that CD8 plays a critical (in some cases obligatory) role in antigen-specific TCR binding. T cell activation, measured by calcium mobilization, was induced by multimeric but not monomeric ligands and also showed CD8 dependency. Our analysis using anti-CD8 antibodies revealed that binding to different epitopes of CD8 can either block or augment TCR-MHC/peptide interaction. These effects on TCR binding to high-affinity agonist ligands were even more pronounced when binding to multimeric low-affinity ligands, including TCR antagonists, was studied. Our data have important implications for the role of CD8 in TCR binding to MHC/peptide ligands and in T cell activation. In addition, our results argue against the view that multimeric MHC/peptide ligands bind directly and solely to the TCR; rather, our data highlight a pivotal contribution of CD8 for this association.
Assuntos
Antígenos CD8/imunologia , Antígenos H-2/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Proteínas do Ovo/imunologia , Humanos , Camundongos , Camundongos Transgênicos , Ovalbumina/imunologia , Fragmentos de Peptídeos , Peptídeos/imunologiaRESUMO
We report solid-state Nuclear Magnetic Resonance (ssNMR) studies on amyloid-like protein complexes formed by DIX domains that mediate key protein interactions in the Wnt signalling pathway. Our results provide insight into the 3D fold of the self-associated Axin-DIX domain and identify a potential lipid cofactor.
Assuntos
Amiloide/química , Proteína Axina/química , Fragmentos de Peptídeos/química , Via de Sinalização Wnt , Proteína Axina/metabolismo , Sítios de Ligação , Humanos , Espectroscopia de Ressonância Magnética , Fragmentos de Peptídeos/metabolismo , Fosfatidiletanolaminas/química , Fosfatidiletanolaminas/metabolismo , Ligação Proteica , Domínios ProteicosRESUMO
Four patients presenting with high grade unilateral vesicoureteral reflux were discovered at surgery to have an unsuspected duplex system with a ureterocele associated with the upper pole of the refluxing kidney. No preoperative radiographic study was diagnostic for duplication or ureterocele but when studies were reviewed retrospectively subtle evidence suggesting this possibility could be identified in a few cases. This rare situation should be considered whenever massive unilateral vesicoureteral reflux is encountered.
Assuntos
Ureter/anormalidades , Ureterocele/complicações , Refluxo Vesicoureteral/complicações , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Radiografia , Ureterocele/diagnóstico por imagem , Refluxo Vesicoureteral/diagnóstico por imagem , Refluxo Vesicoureteral/cirurgiaRESUMO
The mechanism by which TCR antagonists interfere with T cell activation is unclear. One popular hypothesis is that incomplete early signaling events induced by these ligands dominantly inhibit the T cell's ability to respond to a copresented agonist ligand. Here we test this "dominant negative" signal hypothesis by studying T cells expressing two distinct MHC class I-restricted TCRs (2C and OT-I). Although responses through each TCR can be efficiently inhibited by their specific antagonists, we found no evidence for "cross-antagonism" in which an antagonist for receptor "A" blocks responses through receptor "B." Such inhibition would have been expected were the dominant negative signaling hypothesis correct, and alternative models for TCR antagonism are discussed.
Assuntos
Modelos Imunológicos , Receptores de Antígenos de Linfócitos T alfa-beta/antagonistas & inibidores , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Animais , Ligação Competitiva/imunologia , Linhagem Celular , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oligopeptídeos/imunologia , Oligopeptídeos/farmacologia , Ovalbumina/imunologia , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/farmacologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Transdução de Sinais/imunologia , Linfócitos T Citotóxicos/metabolismoRESUMO
Research on patient satisfaction with physician assistants in rural primary care medical practices is lacking. This study attempted to: determine patients' satisfaction with family practice PAs in rural communities, assess patient perceptions of "comfort" with PAs in a range of hypothetical medical procedures, analyze patients' reactions to PAs as a function of patient characteristics, and document perceptions of changes in medical practices after PAs are employed. Findings support reports that patients are highly satisfied with PA services and extends those observations to rural primary care practices. Reaction to PAs is more favorable among women, more favorable in patients with more education, and more favorable among those with greater contact with PAs.
Assuntos
Comportamento do Consumidor , Medicina de Família e Comunidade/normas , Assistentes Médicos , Saúde da População Rural , Estudos de Avaliação como Assunto , Feminino , Humanos , Estatística como Assunto , Estados UnidosRESUMO
The development of biliary tract calculi after orthotopic liver transplantation presents a unique clinical problem. Previously described techniques for removing biliary stones by shock wave lithotripsy, litholytic therapy with oral bile acids, and endoscopic mechanical extraction may be ineffective or contraindicated in liver transplant patients. For this reason, percutaneous transhepatic electrohydraulic lithotripsy (EHL) was performed using an 11 French flexible ureteroscope in two pediatric patients who developed biliary tract calculi following orthotopic liver transplant. There were no complications and postoperative follow-up over 4 years has been uneventful. To our knowledge, these represent the first reported cases of percutaneous transhepatic endoscopic EHL to fragment biliary tract stones in a transplanted liver, which for us has been a safe and effective therapeutic option.
Assuntos
Colelitíase/terapia , Litotripsia/métodos , Transplante de Fígado/efeitos adversos , Adolescente , Criança , Colelitíase/etiologia , Endoscopia do Sistema Digestório , Feminino , Humanos , Complicações Pós-OperatóriasRESUMO
Staining Ag-specific T cells with fluorescently labeled tetrameric MHC/peptide complexes has provided a powerful experimental approach to characterizing the immune response. In this report, we describe an extension of this method to directly visualize Ag-specific T cells in tissues. We successfully stained transgenic T cells with MHC tetramers in spleen sections from both 2C and OT-1 TCR transgenic mice. In addition, with the in situ tetramer staining technique, we detected a very small population of Ag-specific T cells in tissue after adoptive transfer of transgenic TCR T cells to a syngeneic nontransgenic mouse. We also show that the in situ tetramer technique can be applied to lightly fixed as well as frozen tissue, thus extending the method to archived tissue collections. This in situ tetramer staining technique offers a general approach to tracking the Ag-specific T cells in tissues.
Assuntos
Epitopos de Linfócito T/análise , Coloração e Rotulagem/métodos , Linfócitos T/química , Animais , Antígenos CD8/imunologia , Corantes Fluorescentes/análise , Antígenos H-2/análise , Soros Imunes/análise , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Especificidade de Órgãos/genética , Especificidade de Órgãos/imunologia , Receptores de Antígenos de Linfócitos T/análise , Receptores de Antígenos de Linfócitos T/genética , Baço/química , Baço/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Microglobulina beta-2/análiseRESUMO
The widely accepted kinetic proofreading theory proposes that rapid TCR dissociation from a peptide/MHC ligand allows for stimulation of early but not late T cell activation events, explaining why low-affinity TCR ligands are poor agonists. We identified a low-affinity TCR ligand which stimulated late T cell responses but, contrary to predictions from kinetic proofreading, inefficiently induced early activation events. Furthermore, responses induced by this ligand were kinetically delayed compared to its high-affinity counterpart. Using peptide/MHC tetramers, we showed that activation characteristics could be dissociated from TCR occupancy by the peptide/MHC ligands. Our data argue that T cell responses are triggered by a cumulative signal which is reached at different time points for different TCR ligands.
Assuntos
Ativação Linfocitária , Receptores de Antígenos de Linfócitos T/fisiologia , Linfócitos T/imunologia , Animais , Cinética , Camundongos , Modelos Biológicos , Fatores de TempoRESUMO
CD8 serves both as an adhesion molecule for class I MHC molecules and as a coreceptor with the TCR for T cell activation. Here we study the developmental regulation of CD8-mediated binding to noncognate peptide/MHC ligands (i.e., those not bound by the TCR). We show that CD8's ability to bind soluble class I MHC tetramers and to mediate T cell adhesion under shear flow conditions diminishes as double-positive thymocytes mature into CD8(+) T cells. Furthermore, we provide evidence that this decreased CD8 binding results from increased T cell sialylation upon T cell maturation. These data suggest that CD8's ability to interact with class I MHC is not fixed and is developmentally regulated through the T cell's glycosylation state.