RESUMO
BACKGROUND & AIMS: Endoscopic detection of early Barrett's esophagus-related neoplasia (BORN) is a challenge. We aimed to develop a web-based teaching tool for improving detection and delineation of BORN. METHODS: We made high-definition digital videos during endoscopies of patients with BORN and non-dysplastic Barrett's esophagus. Three experts superimposed their delineations of BORN lesions on the videos using special tools. In phase one, 68 general endoscopists from 4 countries assessed 4 batches of 20 videos. After each batch, mandatory feedback compared the assessors' interpretations with those from experts. These data informed the selection of 25 videos for the phase 2 module, which was completed by 121 new assessors from 5 countries. A 5-video test batch was completed before and after scoring of the four 5-video training batches. Mandatory feedback was as in phase 1. Outcome measures were scores for detection, delineation, agreement delineation, and relative delineation of BORN. RESULTS: A linear mixed-effect model showed significant sequential improvement for all 4 outcomes over successive training batches in both phases. In phase 2, median detection rates of BORN in the test batch increased by 30% (P < .001) after training. From baseline to the end of the study, there were relative increases in scores of 46% for detection, 129% for delineation, 105% for agreement delineation, and 106% for relative delineation (all, P < .001). Scores improved independent of assessors' country of origin or level of endoscopic experience. CONCLUSIONS: We developed a web-based teaching tool for endoscopic recognition of BORN that is easily accessible, efficient, and increases detection and delineation of neoplastic lesions. Widespread use of this tool might improve management of Barrett's esophagus by general endoscopists.
Assuntos
Esôfago de Barrett/patologia , Instrução por Computador/métodos , Educação Médica Continuada/métodos , Educação de Pós-Graduação em Medicina/métodos , Neoplasias Esofágicas/patologia , Esofagoscopia/educação , Esôfago/patologia , Internet , Biópsia , Canadá , Transformação Celular Neoplásica/patologia , Competência Clínica , Europa (Continente) , Retroalimentação , Humanos , Variações Dependentes do Observador , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Estados Unidos , Gravação em VídeoRESUMO
The radial distribution of esophago-gastric junction (EGJ) pressures with regard to troublesome dysphagia (TDysph) after antireflux surgery is poorly understood. Before and after antireflux surgery, end-expiratory and peak-inspiratory EGJ pressures were measured at eight angles of 45° radial separation in patients with reflux disease. All 34 patients underwent posterior crural repair, then either 90° anterior (N = 13) or 360° fundoplication (N = 21). Dysphagia was assessed prospectively using a validated questionnaire (score range 0-45) and TDysph defined as a dysphagia score that was ≥5 above pre-op baseline. Compared with before surgery, for 90° fundoplication, end-expiratory EGJ pressures were highest in the left-anterolateral sectors, the position of the partial fundoplication. In other sectors, pressures were uniformly elevated. Compared with 90° fundoplication, radial pressures after 360° fundoplication were higher circumferentially (P = 0.004), with a posterior peak. Nine patients developed TDysph after surgery with a greater increase in end-expiratory and peak-inspiratory EGJ pressures (P = 0.03 and 0.03, respectively) and significantly higher inspiratory pressure at the point of maximal radial pressure asymmetry (P = 0.048), compared with 25 patients without TDysph. Circumferential elevation of end-expiratory EGJ pressure after 90° and 360° fundoplication suggests hiatal repair elevates EGJ pressure by extrinsic compression. The highly localized focal point of elevated EGJ pressure upon inspiration in patients with TDysph after surgery is indicative of a restrictive diaphragmatic hiatus in the presence of a fundoplication.
Assuntos
Transtornos de Deglutição/etiologia , Fundoplicatura/efeitos adversos , Refluxo Gastroesofágico/cirurgia , Herniorrafia/efeitos adversos , Complicações Pós-Operatórias/etiologia , Adulto , Idoso , Transtornos de Deglutição/patologia , Junção Esofagogástrica/patologia , Feminino , Refluxo Gastroesofágico/etiologia , Refluxo Gastroesofágico/patologia , Hérnia Hiatal/complicações , Hérnia Hiatal/patologia , Hérnia Hiatal/cirurgia , Humanos , Masculino , Manometria , Pessoa de Meia-Idade , Complicações Pós-Operatórias/patologia , Pressão , Estudos Prospectivos , Adulto JovemRESUMO
BACKGROUND: Elderly patients are commonly under-represented in cancer clinical trials. The 321GO was undertaken in preparation for a definitive phase three trial assessing different chemotherapy regimens in a frail and/or elderly population with advanced gastroesophageal (GO) cancer. METHODS: Patients with advanced GO cancer considered unfit for conventional dose chemotherapy were randomly assigned in a 1 : 1 : 1 ratio to: epirubicin, oxaliplatin and capecitabine (EOX); oxaliplatin and capecitabine (OX); and capecitabine alone (X) (all 80% of full dose and unblinded). The primary end point was patient recruitment over an 18-month period. A registration study recorded treatment choice for all patients with advanced GO cancer at trial centres. RESULTS: A total of 313 patients were considered for palliative chemotherapy for GO cancer over the 18-month period: 115 received full dose treatment, 89 less than standard treatment or entered 321GO and 111 no treatment. Within 321GO, 55 patients were randomly assigned (19 to OX and X; 17 to EOX). Progression-free survival (PFS) for all patients was 4.4 months and by arm 5.4, 5.6 and 3.0 months for EOX, OX and X, respectively. The number of patients with a good overall treatment utility (OTU), a novel patient-centred endpoint, at 12 weeks was 3 (18%), 6 (32%) and 1 (6%) for EOX, OX and X, respectively. At 6 weeks, 22 patients (41%) had experienced a non-haematologic toxicity ⩾grade 3, most commonly lethargy or diarrhoea. The OTU was prognostic for overall survival in patients alive at week 12 (logrank test P=0.0001). CONCLUSIONS: It is feasible to recruit elderly and/or frail patients with advanced GO cancer to a randomised clinical trial. The OX is the preferred regimen for further study. Overall treatment utility shows promise as a comparator between treatment regimens for feasibility and randomised trials in the elderly and/or frail GO cancer population.
Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Esofágicas/tratamento farmacológico , Idoso Fragilizado , Cuidados Paliativos/métodos , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Idoso , Idoso de 80 Anos ou mais , Capecitabina/administração & dosagem , Capecitabina/efeitos adversos , Desoxicitidina/administração & dosagem , Desoxicitidina/efeitos adversos , Progressão da Doença , Epirubicina/administração & dosagem , Epirubicina/efeitos adversos , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Estudos de Viabilidade , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Humanos , Masculino , Compostos Organoplatínicos/administração & dosagem , Compostos Organoplatínicos/efeitos adversos , OxaliplatinaRESUMO
This study evaluated the acceptability of a supportive model of follow-up. One hundred and twelve women recovering from breast cancer were randomised to receive standard breast clinic aftercare (Control n = 56) or on demand by open access aftercare by breast care nurses (Intervention n = 56). Participants attended a support-based psycho-educational programme delivered in four half-day group sessions. Three quality of life questionnaires (EORTC QLQ-C30, QLQ-BR23, HADS) were administered at baseline and 6-monthly intervals for 2 years. Multilevel linear regression modelling methods were used for evaluation. Age was found to be a statistically significant predictor of quality of life in several sub-scales. Increasing age was negatively associated with sexual functioning, systematic therapy side effects and physical functioning, and positively associated with future perspective. Aftercare assignment was not found to be a statistically significant predictor. Women treated for early breast cancer were not disadvantaged by allocation to the open access supportive care model in terms of quality of life experienced. The model for follow-up was demonstrated to be a feasible alternative to routinised hospital-based follow-up and adds to the evidence for stratified follow-up for low-risk cancer patients, incorporating self-management education. Stratified follow-up pathways are viewed as a preferable approach.
Assuntos
Assistência ao Convalescente/métodos , Neoplasias da Mama/terapia , Acessibilidade aos Serviços de Saúde , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Viabilidade , Feminino , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/etiologia , Recidiva Local de Neoplasia/terapia , Educação de Pacientes como Assunto/métodos , Psicoterapia/métodos , Qualidade de Vida , Autocuidado/métodos , Inquéritos e QuestionáriosRESUMO
AIM: To examine whether low circulating vitamin C concentrations and low fruit and vegetable intakes were associated with insulin resistance and other Type 2 diabetes risk markers in childhood. METHODS: We conducted a cross-sectional, school-based study in 2025 UK children aged 9-10 years, predominantly of white European, South-Asian and black African origin. A 24-h dietary recall was used to assess fruit, vegetable and vitamin C intakes. Height, weight and fat mass were measured and a fasting blood sample collected to measure plasma vitamin C concentrations and Type 2 diabetes risk markers. RESULTS: In analyses adjusting for confounding variables (including socio-economic status), a one interquartile range higher plasma vitamin C concentration (30.9 µmol/l) was associated with a 9.6% (95% CI 6.5, 12.6%) lower homeostatic model assessment of insulin resistance value, 0.8% (95% CI 0.4, 1.2%) lower fasting glucose, 4.5% (95% CI 3.2, 5.9%) lower urate and 2.2% (95% CI 0.9, 3.4%) higher HDL cholesterol. HbA1c concentration was 0.6% (95% CI 0.2, 1.0%) higher. Dietary fruit, vegetable and total vitamin C intakes were not associated with any Type 2 diabetes risk markers. Lower plasma vitamin C concentrations in South-Asian and black African-Caribbean children could partly explain their higher insulin resistance. CONCLUSIONS: Lower plasma vitamin C concentrations are associated with insulin resistance and could partly explain ethnic differences in insulin resistance. Experimental studies are needed to establish whether increasing plasma vitamin C can help prevent Type 2 diabetes at an early stage.
Assuntos
Ácido Ascórbico/administração & dosagem , Ácido Ascórbico/sangue , Glicemia/metabolismo , Ingestão de Alimentos/fisiologia , Frutas , Resistência à Insulina , Verduras , Criança , Estudos Transversais , Diabetes Mellitus Tipo 2/epidemiologia , Diabetes Mellitus Tipo 2/etiologia , Dieta , Feminino , Humanos , Masculino , Fatores de Risco , Fatores Socioeconômicos , Reino Unido/epidemiologiaRESUMO
BACKGROUND: Aromatase inhibitors (AIs) are central to the management of oestrogen receptor-positive breast cancer in the adjuvant and metastatic setting. Levels of circulating steroid hormones (SHs) were measured in patients established on AIs to investigate: the influence of body mass index (BMI) in both the adjuvant and metastatic setting; the class of AI utilized in the adjuvant setting (steroidal versus non-steroidal); and differences in SH levels between women treated adjuvantly and those receiving a second-line AI for locally advanced/metastatic disease. METHODS: Plasma levels of androstenedione, 5-androstene-3ß,17ß-diol, dehydroepiandrosterone, oestradiol and testosterone were measured by radioimmunoassay in women with breast cancer who were receiving AIs in either an adjuvant or a metastatic setting. Differences between mean SH levels by class of AI, BMI, and second-line versus adjuvant therapy were assessed. RESULTS: Sixty-four women were receiving AI therapy, 45 (70 per cent) in an adjuvant setting and 19 (30 per cent) were taking a second-line AI. There was no significant correlation between BMI and SH levels. However, BMI was significantly higher in the second-line AI cohort compared with the adjuvant cohort (29.8 versus 26.2 kg/m2 respectively; P = 0.026). In the adjuvant setting, patients receiving a steroidal AI had significantly higher levels of all five hormones (P < 0.050). In the second-line AI cohort, oestradiol levels were significantly higher than in the adjuvant cohort (4.5 versus 3.3 pg/ml respectively; P = 0.022). Multivariable analysis adjusted for BMI confirmed the higher residual oestradiol level in the second-line AI group (P = 0.063) and a significantly higher androstenedione level (P = 0.022). CONCLUSION: Residual levels of SH were not significantly influenced by BMI. However, the significant differences in residual SH levels between the second-line and adjuvant AI cohort is of relevance in the context of resistance to AI therapy, and warrants further investigation.
Assuntos
Inibidores da Aromatase/uso terapêutico , Índice de Massa Corporal , Neoplasias da Mama/tratamento farmacológico , Neoplasias Hormônio-Dependentes/tratamento farmacológico , Esteroides/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Neoplasias da Mama/metabolismo , Neoplasias da Mama/fisiopatologia , Quimioterapia Adjuvante , Feminino , Hormônios Gonadais/metabolismo , Humanos , Pessoa de Meia-Idade , Metástase Neoplásica , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/fisiopatologia , RadioimunoensaioRESUMO
BACKGROUND: Teaching of clinical skills traditionally takes place in hospital wards and outpatient settings. However high acuity and short hospital stays means there are fewer suitable inpatients available for teaching; and time pressures limit students' involvement in other settings. The Ambulatory Medicine Programme was established to develop undergraduate medical students' clinical skills by providing increased exposure to patients with a wide range of chronic medical conditions, in a dedicated learning environment. METHOD: A mixed qualitative/quantitative approach was used to evaluate the Programme. This research focuses on staff and student perspectives of teaching and learning in Ambulatory Medicine compared with inpatient and outpatient settings; identifies which teaching methods are considered most effective; and determines the transferability of learning. Patients' perspectives of being involved in student teaching are also reported. RESULTS: Results show that the programme has made a positive impact on students' development of clinical skills, which are transferable to the clinical setting. Patients enjoy being involved and find it personally satisfying. CONCLUSIONS: The Ambulatory Medicine Programme is an effective way of developing medical students' clinical skills by providing focussed teaching with real patients in a dedicated learning environment.
Assuntos
Assistência Ambulatorial/organização & administração , Competência Clínica , Educação de Graduação em Medicina/organização & administração , Docentes de Medicina , Estudantes de Medicina , Atitude do Pessoal de Saúde , Currículo , Humanos , Aprendizagem , Percepção , Avaliação de Programas e Projetos de SaúdeRESUMO
AIM: Patients with stage IV colorectal cancer with unresectable metastases can either receive chemotherapy or palliative resection of the primary lesion. In the absence of any randomized data the choice of initial treatment in stage IV colorectal cancer is not based on firm evidence. METHOD: A search of MEDLINE, Pubmed, Embase and the Cochrane Library database was performed from 1980 to 2010 for studies comparing palliative resection in stage IV colorectal cancer with other treatment modalities. Audits and observational studies were excluded. Median survival was the primary outcome measure. The morbidity and mortality of surgical and nonsurgical treatments were compared. RESULTS: Twenty-one studies (no randomized controlled trials) were identified. Most demonstrated a survival benefit for patients who underwent palliative resection. Multivariate analysis indicates that tumour burden and performance status are both major independent prognostic variables. Selection bias, incomplete follow up and nonstandardized reporting of complications make the data difficult to interpret. CONCLUSION: The studies indicate that there may be a survival benefit for primary resection of colorectal cancer in stage IV disease. The findings suggest that resection of the primary tumour should be based on tumour burden and performance status rather than on the presence or absence of symptoms alone.
Assuntos
Neoplasias Colorretais/cirurgia , Cuidados Paliativos , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Humanos , Metástase Neoplásica , Estadiamento de Neoplasias , Análise de Sobrevida , Carga TumoralRESUMO
To study vimentin filament organization in vivo we injected Xenopus oocytes, which have no significant vimentin system of their own, with in vitro-synthesized RNAs encoding Xenopus vimentins. Exogenous vimentins were localized primarily to the cytoplasmic surface of the nucleus and to the subplasma membrane "cortex." In the cortex of the animal hemisphere, wild-type vimentin forms punctate structures and short filaments. In contrast, long anastomosing vimentin filaments are formed in the vegetal hemisphere cortex. This asymmetry in the organization of exogenous vimentin is similar to that of the endogenous keratin system (Klymkowsky, M. W., L. A. Maynell, and A. G. Polson. 1987. Development (Camb.). 100:543-557), which suggests that the same cellular factors are responsible for both. Before germinal vesicle breakdown, in the initial stage of oocyte maturation, large vimentin and keratin filament bundles appear in the animal hemisphere. As maturation proceeds, keratin filaments fragment into soluble oligomers (Klymkowsky, M. W., L. A. Maynell, and C. Nislow. 1991. J. Cell Biol. 114:787-797), while vimentin filaments remain intact and vimentin is hyperphosphorylated. To examine the role of MPF kinase in the M-phase reorganization of vimentin we deleted the conserved proline of vimentin's single MPF-kinase site; this mutation had no apparent effect on the prophase or M-phase behavior of vimentin. In contrast, deletion of amino acids 19-68 or 18-61 of the NH2-terminal "head" domain produced proteins that formed extended filaments in the animal hemisphere of the prophase oocyte. We suggest that the animal hemisphere cortex of the prophase oocyte contains a factor that actively suppresses the formation of extended vimentin filaments through a direct interaction with vimentin's head domain. During maturation this "suppressor of extended filaments" appears to be inactivated, leading to the formation of an extended vimentin filament system.
Assuntos
Filamentos Intermediários/química , Oócitos/química , Vimentina/química , Sequência de Aminoácidos , Animais , Sequência de Bases , Células Cultivadas , Filamentos Intermediários/ultraestrutura , Microscopia Imunoeletrônica , Mitose , Dados de Sequência Molecular , Oócitos/metabolismo , Fosforilação , Vimentina/análise , Vimentina/metabolismo , XenopusRESUMO
The nematode pharynx has a potassium channel with unusual properties, which allows the muscles to repolarize quickly and with the proper delay. Here, the Caenorhabditis elegans exp-2 gene is shown to encode this channel. EXP-2 is a Kv-type (voltage-activated) potassium channel that has inward-rectifying properties resembling those of the structurally dissimilar human ether-à-go-go-related gene (HERG) channel. Null and gain-of-function mutations affect pharyngeal muscle excitability in ways that are consistent with the electrophysiological behavior of the channel, and thereby demonstrate a direct link between the kinetics of this unusual channel and behavior.
Assuntos
Caenorhabditis elegans/fisiologia , Canais de Potássio/fisiologia , Potenciais de Ação , Animais , Caenorhabditis elegans/genética , Comportamento Alimentar , Genes de Helmintos , Genes Reporter , Ativação do Canal Iônico , Cinética , Potenciais da Membrana , Modelos Moleculares , Músculos/metabolismo , Mutação , Neurônios/metabolismo , Oócitos/metabolismo , Músculos Faríngeos/fisiologia , Canais de Potássio/química , Canais de Potássio/genética , Conformação Proteica , RNA Complementar/genética , Proteínas Recombinantes de Fusão/biossíntese , Xenopus laevisRESUMO
Gastroesophageal reflux disease (GERD) may be accompanied by erosive complications that are diagnosed by endoscopy. This study aimed to describe the characteristics of patients newly diagnosed with GERD who are referred for endoscopy, and the factors associated with esophageal endoscopic findings. This study included patients aged 2-79 years with a first recorded diagnosis of GERD in 1996, as identified in a previous cohort study in the UK General Practice Research Database. The rate and results of endoscopy were recorded. Unconditional logistic regression analysis was used to estimate the odds ratios and 95% confidence intervals for the relationship between a range of factors and endoscopy and its findings. Of the 7159 patients with a new GERD diagnosis, 805 (11%) underwent endoscopy close to the time of first consultation for GERD. Endoscopic findings indicative of esophageal damage were recorded in 73% of these patients. Esophageal endoscopic findings were significantly more likely in males, older patients, and individuals with a history of peptic ulcer disease or gastrointestinal bleeding. Use of acid-suppressive drugs, particularly proton pump inhibitors, was inversely associated with erosive endoscopic findings. Patients with erosive endoscopic findings were more likely to start a new course of treatment with a proton pump inhibitor. In conclusion, relatively few patients are referred for endoscopy close to the first consultation for GERD, and the majority of these individuals have esophageal findings. Male gender, increasing age and a history of bleeding were risk factors for esophageal complications.
Assuntos
Bases de Dados Factuais , Esofagoscopia , Refluxo Gastroesofágico/diagnóstico , Gastroscopia , Sistema de Registros , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Refluxo Gastroesofágico/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Reino UnidoRESUMO
In this report we demonstrate that proteolytic cleavage of the constituent subunit is one of the causes determining the heterogeneous size distribution of plasma von Willebrand factor (vWf) multimers. As shown by two-dimensional nonreduced/reduced agarose/polyacrylamide gel electrophoresis, the structure of circulating vWf molecules may deviate from that represented by assemblage of a variable number of identical subunits. Indeed, even though the largest multimers in normal plasma appear to be composed predominantly of intact 225-kD subunits, those of intermediate and smaller size contain also 189-, 176-, and 140-kD proteolytic fragments. Different subunit composition patterns are repeated regularly in multimers of increasing molecular mass, yielding series of bands with similar structure. One of these series consists of molecules without evidence of proteolytic fragmentation, and its smallest member appears to be a dimer of 225-kD subunits. Type IIA von Willebrand disease, characterized by absence of the largest multimers, displays a pattern wherein the fragments of 176 and 140 kD are relatively increased, that of 189 kD is markedly decreased or absent, but the composition of individual multimers is otherwise similar to that of species seen also in normal plasma. In contrast to those in the circulation, all normal platelet vWf multimers contain only intact subunit. These results suggest that proteolytic cleavage of plasma vWf subunits occurs after release from cellular sites, whereas platelet vWf stored in alpha-granules is protected from proteolysis. These findings provide information that may be relevant for understanding the normal processing of vWf multimers and for elucidating the pathogenesis of some of the congenital and acquired structural abnormalities of this molecule.
Assuntos
Fator de von Willebrand/análise , Ácido Edético/farmacologia , Eletroforese em Gel Bidimensional , Humanos , Peso Molecular , Fragmentos de Peptídeos/análise , Fator de von Willebrand/metabolismoRESUMO
We have evaluated the subunit composition of plasma von Willebrand factor (vWF) and found evidence that cleavage is present in normal individuals, increased in IIA and IIB von Willebrand disease (vWD), but decreased or absent in variants with aberrant structure of individual oligomers. vWF was rapidly purified from plasma on an analytical scale by monoclonal antibody immunoaffinity chromatography in the presence of protease inhibitors. After reduction and electrophoresis in 5% polyacrylamide gels containing sodium dodecyl sulfate, fragments of 189, 176, and 140 kD, as well as the predominant 225-kD subunit, were identified in plasma vWF from 25 normal individuals. The vWF polypeptides were detected by immunoblotting with a mixture of 55 anti-vWF monoclonal antibodies followed by 125I-rabbit anti-mouse antibody and autoradiography. In five individuals with type IIA and five individuals with type IIB vWD, the proportions of 176 and 140-kD fragments were increased relative to the intact 225-kD subunit, as determined by excising each band and quantitating incorporated radioactivity. In contrast, these fragments were either not detectable or were present in only trace amounts in variants with abnormal structure of individual oligomers (types IIC and IID, and a new variant, type IIE vWD). The results reported here provide evidence that absence of large vWF multimers in these two groups of variants results from different mechanisms. In addition, they demonstrate that partial cleavage of the plasma vWF subunit is a normal event.
Assuntos
Doenças de von Willebrand/sangue , Fator de von Willebrand/metabolismo , Anticorpos Monoclonais , Humanos , Substâncias Macromoleculares , Peso Molecular , Fragmentos de Peptídeos/análise , Doenças de von Willebrand/classificação , Doenças de von Willebrand/genética , Fator de von Willebrand/genéticaRESUMO
We investigated the mechanism of gastroesophageal reflux (GER) in 10 health volunteer subjects. Continuous recordings of intraluminal esophageal pH and pressure were obtained on two consecutive nights from 6:00 p.m. to 6:30 a.m. in each subject. During each study, the subject remained recumbent, except to eat a standardized meal after 1 h of basal recording. A manometric assembly with seven recording lumens monitored: (a) lower esophageal sphincter (LES) pressure via a sleeve device 6.5 cm in length, (b) esophageal-body motor activity, (c) swallowing activity in the pharynx, and (d) gastric pressure. An electrode 5 cm above the LES recorded esophageal pH. Sleep was monitored by electroencephalogram. All subjects showed wide variations of basal LES pressure. GER was not related to low steady-state basal LES pressure, but rather occurred during transient 5-30 s episodes of inappropriate complete LES relaxation. The inappropriate LES relaxations were usually either spontaneous or immediately followed appropriate sphincter relaxation induced by swallowing. The majority of GER episodes occurred within the first 3 h after eating. During the night LES relaxation and GER occurred only during transient arousals from sleep or when the subjects were fully awake, but not during stable sleep. After GER the esophagus was generally cleared of refluxed acid by primary peristalsis and less frequently by secondary peristalsis. Nonperistaltic contractions were less effective than peristalsis for clearing acid from the esophagus. We conclude that in asymptomatic recumbent subjects GER is related to transient inappropriate LES relaxations rather than to low steady-state basal LES pressure and also, that primary perstalsis is the major mechanism that clears the esophagus of refluxed material.
Assuntos
Junção Esofagogástrica/fisiopatologia , Refluxo Gastroesofágico/etiologia , Adulto , Deglutição , Refluxo Gastroesofágico/fisiopatologia , Humanos , Concentração de Íons de Hidrogênio , Peristaltismo , Postura , Pressão , Fases do SonoRESUMO
Variant von Willebrand disease designated as type I New York or type Malmö is characterized by enhanced ristocetin-induced platelet agglutination with normal von Willebrand factor multimeric distribution in plasma. We have studied four such patients belonging to three unrelated families and found in all of them a unique cytosine-to-thymine transition changing the codon for Pro503 (CCG) to Leu (CTG). In three patients the mutant allele also had a silent mutation in the codon for Ser500 (TCG-->TCA). Both nucleotide changes are present in the von Willebrand factor pseudogene; however, the characterization of distinctive markers where the gene and pseudogene differ, as well as the examination of amplified cDNA derived from platelet mRNA, confirmed that the abnormality occurs in the von Willebrand factor gene of the patients. Moreover, recombinant expression of the isolated glycoprotein Ib-binding domain of von Willebrand factor provided direct evidence that the Pro503-->Leu mutation is responsible for enhanced platelet reactivity to lower ristocetin concentrations. These results define a new structural element affecting the affinity of von Willebrand factor for glycoprotein Ib and establish the molecular basis of a variant form of von Willebrand disease.
Assuntos
Plaquetas/metabolismo , Mutação Puntual , Prolina , Fator de von Willebrand/genética , Fator de von Willebrand/metabolismo , Adulto , Alelos , Sequência de Aminoácidos , Animais , Sequência de Bases , Células CHO , Códon/genética , Cricetinae , DNA/sangue , DNA/genética , DNA/isolamento & purificação , Éxons , Feminino , Humanos , Íntrons , Leucina , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oligodesoxirribonucleotídeos , Reação em Cadeia da Polimerase/métodos , Proteínas Recombinantes/metabolismo , TransfecçãoRESUMO
A small but consistent proportion of the von Willebrand factor (vWF) in normal plasma is composed of 189, 176, and 140 kD fragments cleaved from the 225 kD subunit. A monoclonal antibody map of vWF, based on the reactivity of individual antibodies with cyanogen bromide and tryptic fragments of known carboxy and/or amino termini, showed that in normal and IIA von Willebrand disease (vWD) plasmas the 140 kD fragment was derived from the amino-terminal region, whereas the 176 kD fragment was derived from the carboxy-terminal region of the subunit. In type IIA vWD, however, the fragments comprised a greater proportion of circulating vWF. In contrast, plasmin cleaved a 176 kD fragment from the amino terminus and a 145 kD fragment from the carboxy terminus of the subunit. Species similar to these plasmin-cleaved fragments were demonstrated in plasmas from four patients treated with fibrinolytic agents, but not in IIA vWD.
Assuntos
Epitopos/análise , Fibrinolisina/metabolismo , Doenças de von Willebrand/sangue , Fator de von Willebrand/imunologia , Anticorpos Monoclonais , Humanos , Substâncias Macromoleculares , Peso Molecular , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/imunologia , Fator de von Willebrand/análiseRESUMO
BACKGROUND AND STUDY AIMS: This study tested the diagnostic value of high-resolution endoscopy for the recognition of subtle diagnostic esophageal mucosal changes in nonerosive reflux disease. PATIENTS AND METHODS: Ten control subjects and eleven patients with nonerosive reflux disease confirmed by a validated questionnaire, standard endoscopy, and 24-hour pH-metry participated in the study. Still images were collected by high-resolution endoscopes from the distal esophagus in a standardized manner, incorporating iodine staining. Assessments were repeated in the patients with reflux disease after 4 weeks of esomeprazole therapy. Interobserver variability in the recognition of the proposed criteria was initially evaluated by 27 endoscopists using an Internet-based process. After optimisation of image quality the evaluation was repeated face-to-face with six expert endoscopists. RESULTS: No criterion was identified in either assessment that was sufficiently sensitive and specific to patients with reflux disease to be clinically useful. The kappa value, used to assess interobserver variation, was acceptably high only for invisibility of palisade vessels (0.59). Triangular indentations, apical mucosal breaks, and pinpoint blood vessels at the squamocolumnar junction were identified more frequently in the patients with reflux disease ( P < 0.05). These changes and the invisibility of the palisade vessels were significantly less prevalent in reflux patients after therapy ( P < 0.01). CONCLUSIONS: Though some distal esophageal mucosal appearances observed with the high-resolution endoscope appeared to be related to nonerosive esophageal mucosal injury, none of these changes proved to be sufficiently sensitive and specific to justify their use as a diagnostic criterion for nonerosive reflux disease.
Assuntos
Endoscopia Gastrointestinal/métodos , Refluxo Gastroesofágico/diagnóstico , Aumento da Imagem , Adulto , Diagnóstico Diferencial , Feminino , Refluxo Gastroesofágico/metabolismo , Humanos , Masculino , Variações Dependentes do Observador , Reprodutibilidade dos TestesRESUMO
BACKGROUND: The diagnosis of gastro-oesophageal reflux disease (GERD) in clinical practice is limited by the sensitivity and specificity of symptoms and diagnostic testing. AIM: To determine if adding histology as a criterion and excluding patients with epigastric pain enhances the diagnosis for GERD. METHODS: Patients with frequent upper gastrointestinal symptoms who had not taken a proton pump inhibitor in the previous 2 months and who had evaluable distal oesophageal biopsies were included (Diamond study: NCT00291746). Epithelial hyperplasia was identified when total epithelial thickness was at least 430 µm. Investigation-based GERD criteria were: presence of erosive oesophagitis, pathological oesophageal acid exposure and/or positive symptom-acid association probability. Symptoms were assessed using the Reflux Disease Questionnaire and a pre-specified checklist. RESULTS: Overall, 127 (55%) of the 231 included patients met investigation-based GERD criteria and 195 (84%) met symptom-based criteria. Epithelial hyperplasia was present in 89 individuals, of whom 61 (69%) met investigation-based criteria and 83 (93%) met symptom-based criteria. Adding epithelial hyperplasia as a criterion increased the number of patients diagnosed with GERD on investigation by 28 [12%; number needed to diagnose (NND): 8], to 155 (67%). The proportion of patients with a symptom-based GERD diagnosis who met investigation-based criteria including epithelial hyperplasia was significantly greater when concomitant epigastric pain was absent than when it was present (P < 0.05; NND: 8). CONCLUSIONS: Histology increases diagnosis of GERD and should be performed when clinical suspicion is high and endoscopy is negative. Excluding patients with epigastric pain enhances sensitivity for the diagnosis of GERD.
Assuntos
Dor Abdominal/diagnóstico , Refluxo Gastroesofágico/diagnóstico , Refluxo Gastroesofágico/patologia , Técnicas Histológicas , Dor Abdominal/complicações , Adulto , Biópsia , Diagnóstico Diferencial , Endoscopia , Esofagite/diagnóstico , Esofagite/patologia , Feminino , Refluxo Gastroesofágico/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Septins are important effectors in molecular mechanisms involving membrane partitioning. To date, a growing repertoire of septins in mammals includes 13 different proteins (SEPT1 to SEPT13) that can be classified into four distinct categories based on sequence similarity. AIM: In this study, we document the human platelet septin, SEPT5, as part of a complex composed of multiple septin proteins. RESULTS: Biochemical and immunofluorescent data place the majority of these complexes in the platelet periphery as part of the platelet circumferential band copurifying with the platelet microtubule coil and tubulin. The presence of a prominent platelet septin ring in resting platelets appears to be left intact in the activated platelet, as a similar ring structure is observed following platelet spreading on fibrinogen. The ablation of SEPT5 in the knock-out mouse model had previously been reported to result in a platelet phenotype with aggregation using subthreshold levels of agonist. Speculation on the role of SEPT5 in the platelet-release reaction suggested that SEPT5 regulates platelet function by association with platelet storage granules. We now report that the absence of SEPT5 results in increased ATP release from stimulated platelets. CONCLUSION: These studies document the presence of platelet septin complexes and validate the importance of septins for platelet physiology.
Assuntos
Plaquetas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Microtúbulos/metabolismo , Tubulina (Proteína)/metabolismo , Trifosfato de Adenosina/biossíntese , Animais , Plaquetas/efeitos dos fármacos , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/genética , Colágeno Tipo I/farmacologia , Proteínas do Citoesqueleto , Proteínas de Ligação ao GTP/química , Humanos , Camundongos , Camundongos Knockout , Microtúbulos/química , Nocodazol/farmacologia , Ligação Proteica , Septinas , Tubulina (Proteína)/química , Moduladores de Tubulina/farmacologiaRESUMO
BACKGROUND: Our understanding of gastro-oesophageal reflux disease has undergone significant changes over the last century. AIM: To trace the rise in understanding of gastro-oesophageal reflux disease and highlight remaining areas of uncertainty. METHODS: Literature review. RESULTS: In 1906, Tileston published his observations on 'peptic ulcer of the oesophagus'. Winkelstein, in 1934, first correlated symptoms of heartburn with acid regurgitation and reflux oesophagitis. In 1946, Allison described hiatus hernia as a causal factor in the development of gastro-oesophageal reflux disease. In 1958, Bernstein and Baker showed a direct relationship between oesophageal acidification and heartburn in patients with gastro-oesophageal reflux disease, irrespective of endoscopic findings, leading to the recognition of non-erosive gastro-oesophageal reflux disease. In the 1980s, continuous recordings of the lower oesophageal sphincter showed that episodes of reflux were related to transient relaxations of lower oesophageal sphincter tone. There is now increasing recognition that gastro-oesophageal reflux disease arises from the interaction of several anatomical and physiological factors. A turning point in the medical treatment of gastro-oesophageal reflux disease came with the introduction of the first proton pump inhibitor, omeprazole, in 1989. CONCLUSIONS: Future efforts need to identify the multifactorial interactions of gastro-oesophageal junction anatomy and physiology in patients with gastro-oesophageal reflux disease. Increased understanding of the disease will guide development of new therapies.