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INTRODUCTION: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is frequently used to risk-stratify pancreatic cystic lesions (PCLs). Rising PCL incidence and developments in tissue acquisition and specimen analysis necessitate updated appraisal of EUS-FNA safety, particularly the risk of postprocedure pancreatitis, the most common EUS-FNA-related adverse event. Our systematic review aims to accurately quantify the risk of EUS-FNA-related pancreatitis to best inform decisions regarding EUS-FNA's optimal role in PCL workup. METHODS: We performed systematic searches in 4 databases from inception to April 2024 for original English-language studies investigating EUS-FNA-related pancreatitis. We extracted data on demographics and EUS-FNA-related pancreatitis risk, severity, and risk factors. These were meta-analyzed through the DerSimonian Laird Method using a random-effects model. Meta-regression of pancreatitis risk was performed to delineate associations with clinical and procedural characteristics. RESULTS: Sixty-four studies comprised 8,086 patients and reported 110 EUS-FNA-related pancreatitis events. Pooled risk of EUS-FNA-related pancreatitis was 1.4% (95% confidence intervals, -0.8% to 3.5%; I2 = 0.00), which was predominantly of mild severity (67%) and uniformly nonfatal. Pancreatitis risk lacked significant association with sample size, age, sex, cyst size, needle caliber, or passes, although we noted trends toward higher risk in studies published after 2015, those using higher gauge needles (19 G vs 22 G/25 G), and those performing EUS-guided through-the-needle biopsy. DISCUSSION: We note with high certainty that pancreatitis after EUS-FNA of PCLs is infrequent and mild in severity with no mortality in the included cohort. EUS-guided through-the-needle biopsy may serve as a significant risk factor for EUS-FNA-related pancreatitis risk; however, further studies are needed to delineate other predisposing characteristics.
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BACKGROUND AND AIMS: Endoscopic-related injuries (ERIs) for gastroenterologists are common and can impact longevity of an endoscopic career. This study examines sex differences in the prevalence of ERIs and ergonomic training during gastroenterology fellowship. METHODS: A 56-item anonymous survey was sent to 709 general and advanced endoscopy gastroenterology fellows at 73 U.S. training programs between May and June 2022. Demographic information was collected along with questions related to endoscopic environment, ergonomic instruction, technique, equipment availability, and ergonomic knowledge. Responses of female and male gastroenterology fellows were compared using χ2 and Fisher exact tests. RESULTS: Of the 236 respondents (response rate, 33.9%), 113 (44.5%) were women and 123 (52.1%) were men. Female fellows reported on average smaller hand sizes and shorter heights. More female fellows reported endoscopic equipment was not ergonomically optimized for their use. Additionally, more female fellows voiced preference for same-gender teachers and access to dial extenders and well-fitting lead aprons. High rates of postendoscopy pain were reported by both sexes, with significantly more women experiencing neck and shoulder pain. Trainees of both sexes demonstrated poor ergonomic awareness with an average score of 68% on a 5-point knowledge-based assessment. CONCLUSIONS: Physical differences exist between male and female trainees, and current endoscopic equipment may not be optimized for smaller hand sizes. This study highlights the urgent need for formal ergonomic training for trainees and trainers with consideration of stature and hand size to enhance safety, comfort, and equity in the training and practice of endoscopy.
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Gastroenterologistas , Gastroenterologia , Humanos , Masculino , Feminino , Gastroenterologia/educação , Caracteres Sexuais , Endoscopia Gastrointestinal/educação , Gastroenterologistas/educação , Inquéritos e Questionários , Bolsas de Estudo , ErgonomiaRESUMO
BACKGROUND: Under-reporting of clinical trial results can lead to negative consequences that include inhibiting propagation of knowledge, limiting the understanding of how devices work, affecting conclusions of meta-analyses, and failing to acknowledge patient participation. Therefore clinical trial transparency, through publication of trial results on ClinicalTrials.gov or in manuscript form, is important. We aimed to examine clinical trial transparency in endoscopic clinical trials. METHODS: The ClinicalTrials.gov database was searched for endoscopy trials up to October 2019. Adherence to the reporting of results to the database or in publication form was recorded for each trial. RESULTS: The final analysis included 923 trials, of which 801 were completed and 122 were either terminated or suspended. Results were available either on ClinicalTrials.gov or in publication for 751/923 trials (81.4â%). Other fields have reported a publication rate of 40â%-63â%. Results were available on ClinicalTrials.gov for 168 trials (18.2â%) and in the form of a publication for 720 trails (78.0â%). CONCLUSIONS: Compared with other fields in medicine, endoscopy clinical trials have a high rate of clinical trial transparency. However, there is room for improvements as close to one-fifth of trials fail to report results and 81.8â% do not report results to ClinicalTrials.gov.
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Endoscopia Gastrointestinal , Humanos , Sistema de Registros , Bases de Dados FactuaisRESUMO
INTRODUCTION: There is limited information on the transparency of gastroenterology clinical trials. METHODS: The ClinicalTrials.gov database was searched for trials focused on most common gastrointestinal diseases up to August 2018. Adherence to reporting of results to the database or in publication form was recorded for each trial along with trial characteristics. RESULTS: Of the 2,429 trials included in the final analysis, 1824 (75%, 95% confidence interval: 73.4%-76.8%) had results on ClinicalTrials.gov or in the form of a publication. However, only 534 (29%) had results posted on ClinicalTrials.gov. DISCUSSION: Improvement of clinical trial transparency is needed in gastroenterology.
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Ensaios Clínicos como Assunto/organização & administração , Gastroenterologia , Gastroenteropatias/terapia , Publicações Periódicas como Assunto/estatística & dados numéricos , Sistema de Registros , Bases de Dados Factuais , HumanosRESUMO
Gastrointestinal (GI) symptoms are highly prevalent in coronavirus disease 2019 (COVID-19) ranging from 17.6 % to 53 %.1-4 The proposed mechanism for GI symptoms involves SARS-CoV-2 virus binding to the host cell's angiotensin-converting enzyme-2 receptor, commonly found in GI tract epithelial cells.5.
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COVID-19 , Gastroenteropatias , Gastroenteropatias/diagnóstico , Trato Gastrointestinal , Hospitalização , Humanos , SARS-CoV-2RESUMO
Despite improvements in medical management, 10%-15% of patients with ulcerative colitis (UC) require total proctocolectomy (TPC) with ileal pouch anal anastomosis (IPAA) for refractory disease.1 Acute pouchitis is the most common post-IPAA inflammatory condition, with cumulative incidence of 45% at 5 years.2 Up to 20%-30% of patients develop chronic pouch inflammation (CPI), categorized as antibiotic responsive, antibiotic refractory, or Crohn's disease-like (CDL).3.
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Colite Ulcerativa , Bolsas Cólicas , Pouchite , Proctocolectomia Restauradora , Colite Ulcerativa/tratamento farmacológico , Colite Ulcerativa/cirurgia , Bolsas Cólicas/efeitos adversos , Humanos , Inflamação , Pouchite/tratamento farmacológico , Proctocolectomia Restauradora/efeitos adversos , Falha de TratamentoRESUMO
BACKGROUND: Approximately 10% to 20% of patients with ulcerative colitis require surgery during their disease course, of which the most common is the staged restorative proctocolectomy with IPAA. OBJECTIVE: The aim was to compare the rates of anastomotic leaks among all staged restorative proctocolectomy with IPAA procedures. DESIGN: This was a retrospective cohort study. SETTINGS: This study was conducted at a single tertiary care IBD center. PATIENTS: All patients with ulcerative colitis or IBD-unspecified who underwent a primary total proctocolectomy with IPAA for medically refractory disease or dysplasia between 2008 and 2017 were identified. MAIN OUTCOME MEASURES: The primary outcome was anastomotic leak within a 6-month postoperative period. Univariate and multivariate logistic regression were used to compare patients with and without anastomotic leaks. RESULTS: The sample was composed of 584 nonemergent patients, of whom 50 (8.6%) underwent 1-stage, 162 (27.7%) underwent 2-stage, 58 (9.9%) underwent modified 2-stage, and 314 (53.7%) underwent a 3-stage total proctocolectomy with IPAA. The primary indication was medically refractory disease in 488 patients and dysplasia/cancer in 101 patients. Anastomotic leak occurred in 10 patients (3.2%) after 3-stage, 14 patients (8.6%) after 2-stage, 6 patients (10.3%) after modified 2-stage, and 10 patients (20.0%) after a 1-stage procedure. A 3-stage procedure had fewer leaks and additional procedures for leaks compared with 1- and modified 2-stage procedures (p < 0.03). The 3-stage procedure had fewer combined anastomotic leaks and pelvic abscesses than all of the other staged procedures (p < 0.05). LIMITATIONS: This study was limited by its retrospective design and evolving electronic medical charts system. CONCLUSIONS: The 3-stage total proctocolectomy with IPAA is the optimal staged method in ulcerative colitis to reduce leaks and related complications. See Video Abstract at http://links.lww.com/DCR/B693. LENTO Y CONSTANTE GANA LA CARRERA UN CASO SLIDO PARA UN ENFOQUE DE TRES ETAPAS EN LA COLITIS ULCEROSA: ANTECEDENTES:Aproximadamente el 10-20% de los pacientes con colitis ulcerosa requieren cirugía durante el curso de su enfermedad, de los cuales la más común es la proctocolectomía restauradora escalonada con anastomosis con bolsa ileo-anal.OBJETIVO:El objetivo fue comparar las tasas de fugas anastomóticas entre todos los procedimientos de proctocolectomía restauradora por etapas con procedimiento de anastomosis con bolsa ileo-anal.DISEÑO:Este fue un estudio de cohorte retrospectivo.ENTORNO CLÍNICO:Este estudio se llevó a cabo en un único centro de atención terciaria de tercer nivel para enfermedades inflamatorias del intestino.PACIENTES:Se identificaron todos los pacientes con colitis ulcerosa o enfermedad inflamatoria intestinal inespecífica que se sometieron a una proctocolectomía total primaria mas anastomosis con bolsa ileo-anal por enfermedad médicamente refractaria o displasia entre 2008 y 2017.PRINCIPALES MEDIDAS DE RESULTADO:El resultado primario fue la fuga anastomótica dentro de un período posoperatorio de seis meses. Se utilizó regresión logística univariante y multivariante para comparar pacientes con y sin fugas anastomóticas.RESULTADOS:La muestra estuvo compuesta por 584 pacientes no emergentes, de los cuales 50 (8,6%) se sometieron a una etapa, 162 (27,7%) se sometieron a dos etapas, 58 (9,9%) se sometieron a modificación en dos etapas y 314 (53,7%) se sometieron a una proctocolectomía total en tres tiempos mas anastomosis con bolsa ileo-anal. La indicación principal fue enfermedad médicamente refractaria en 488 pacientes y displasia / cáncer en 101 pacientes. Se produjo una fuga anastomótica en 10 (3,2%) pacientes después de tres etapas, 14 (8,6%) pacientes después de dos etapas, 6 (10,3%) pacientes después de dos etapas modificadas y 10 (20,0%) pacientes después de una etapa procedimiento. Un procedimiento de tres etapas tuvo menos fugas y procedimientos adicionales para las fugas en comparación con los procedimientos de una y dos etapas modificadas (p <0.03). El procedimiento de tres etapas tuvo menos fugas anastomóticas y abscesos pélvicos combinados que todos los demás procedimientos por etapas (p <0,05).LIMITACIONES:Este estudio estuvo limitado por su diseño retrospectivo y su sistema de registros médicos electrónicos en evolución.CONCLUSIONES:La proctocolectomía total en tres etapas mas anastomosis con bolsa ileo-anal es el método óptimo por etapas en la colitis ulcerosa para reducir las fugas y las complicaciones relacionadas. Consulte Video Resumen en http://links.lww.com/DCR/B693.
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Anastomose Cirúrgica/efeitos adversos , Fístula Anastomótica/epidemiologia , Colite Ulcerativa/cirurgia , Complicações Pós-Operatórias/epidemiologia , Proctocolectomia Restauradora/efeitos adversos , Abscesso/diagnóstico , Abscesso/epidemiologia , Adulto , Anastomose Cirúrgica/classificação , Estudos de Casos e Controles , Neoplasias do Colo/epidemiologia , Neoplasias do Colo/patologia , Neoplasias do Colo/cirurgia , Bolsas Cólicas/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Infecção Pélvica/patologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/patologia , Proctocolectomia Restauradora/métodos , Procedimentos Cirúrgicos Operatórios/classificaçãoRESUMO
PURPOSE: Rising obesity and type 2 diabetes mellitus (T2DM) rates can be mitigated by various strategies, with a 10% total body weight loss (TBWL) threshold often required for T2DM remission. T2DM remission rates after bariatric surgery like Roux-en-Y gastric bypass (RYGB) are well established; endoscopic sleeve gastroplasty (ESG) is a less invasive option that averages 15% TBWL and allows for T2DM remission. This study explores the DiaRem (Diabetes Remission post-RYGB) score's ability to predict T2DM remission 1-year post-ESG. MATERIALS AND METHODS: We conducted a retrospective cohort study on 39 individuals with T2DM who underwent ESG. Age, utilization of diabetes medications, insulin administration, and hemoglobin A1c levels were used to calculate the DiaRem score. The area under the receiver operating characteristic curve (AUC) was employed to evaluate the discriminative ability of DiaRem in distinguishing diabetes remission. RESULTS: Among the 39 patients with a median hemoglobin A1c of 6.7, 12.8% required insulin, and 43.6% used diabetes medication. At 1-year post-ESG, 69.2% of patients experienced diabetes remission with a median %TWBL of 12.7. The DiaRem score's ability to detect diabetes resolution for ESG patients had a sensitivity of 100% and a specificity of 58.3%, at the optimal cutoff value of 10. The AUC was 0.779 (95% CI 0.546-0.959). CONCLUSION: Our study demonstrated the DiaRem score's predictive value for T2DM remission post-ESG, highlighting its utility in clinical decision-making for ESG-related outcomes. Further investigation is needed to identify alternative indicators that may enhance predictive accuracy, thus refining personalized decision-making for this patient group.
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Long COVID is a novel syndrome characterizing new or persistent symptoms weeks after COVID-19 infection and involving multiple organ systems. This review summarizes the gastrointestinal and hepatobiliary sequelae of long COVID syndrome. It describes potential biomolecular mechanisms, prevalence, preventative measures, potential therapies, and health care and economic impact of long COVID syndrome, particularly of its gastrointestinal (GI) and hepatobiliary manifestations.
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COVID-19 , Humanos , Síndrome de COVID-19 Pós-Aguda , Progressão da DoençaRESUMO
PURPOSE: The most common surgery for ulcerative colitis (UC) is the staged restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). On occasion, an emergent first-stage subtotal colectomy must be performed. The purpose of this study was to compare rates of postoperative complications in three-stage IPAA patients who underwent emergent vs non-emergent first-stage subtotal colectomies in the subsequent staged procedures. METHODS: This was a retrospective chart review conducted at a single tertiary care inflammatory bowel disease (IBD) center. All UC or IBD-Unspecified patients who underwent a three-stage IPAA between 2008 and 2017 were identified. Emergent surgery was defined as that performed on an inpatient who had perforation, toxic megacolon, uncontrolled hemorrhage, or septic shock. The primary outcomes were the presence of anastomotic leak, obstruction, bleeding, and the need for reoperation for each within a 6-month postoperative period of the second (RPC with IPAA and DLI) and third surgical stages (ileostomy reversal). RESULTS: A total of 342 patients underwent a three-stage IPAA, of which 30 (9.4%) had emergent first-stage operations. Patients who underwent an emergent STC were more likely to have a post-operative anastomotic leak and need an additional procedure following the subsequent second and third-staged operations on both univariate and multivariate analysis (p < 0.05). No difference was found for obstruction, wound infection, intra-abdominal abscess, or bleeding (p > 0.05). CONCLUSION: Three-stage IPAA patients with emergent first-stage subtotal colectomies were more likely to have a post-operative anastomotic leak and need an additional procedure for a leak following the subsequent second- and third-stage operations.
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Colite Ulcerativa , Bolsas Cólicas , Proctocolectomia Restauradora , Humanos , Fístula Anastomótica/epidemiologia , Fístula Anastomótica/etiologia , Fístula Anastomótica/cirurgia , Estudos Retrospectivos , Resultado do Tratamento , Proctocolectomia Restauradora/efeitos adversos , Proctocolectomia Restauradora/métodos , Colectomia/efeitos adversos , Colite Ulcerativa/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgiaRESUMO
Medical rescue therapy for patients with severe steroid-refractory ulcerative colitis (UC) consists of intravenous (IV) cyclosporine or infliximab and remains limited. Cyclosporine is used by fewer medical facilities due to comfort and need for close drug level monitoring, despite evidence that it can have dramatic benefits. In many tertiary centers it is accepted that after 3-7 days of treatment with IV cyclosporine without response, a patient will not respond to the therapy, and other modalities, namely surgery, should be considered. We present the case of a 36-year-old man with acute severe UC refractory to steroids and multiple biologics, who "failed" IV cyclosporine for 2 weeks, much longer than the usually accepted induction phase, and achieved remission with continuation of oral cyclosporine. This case demonstrates the possibility that continued therapy with cyclosporine for a longer duration than the currently accepted timeline can lead to remission and avoidance of colectomy in properly selected and monitored patients.
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BACKGROUND: Total proctocolectomy (TPC) with ileal pouch anal anastomosis (IPAA) is the gold standard surgery for ulcerative colitis (UC) patients with medically refractory disease. The aim of this study was to report the rates and risk factors of inflammatory pouch conditions. METHODS: This was a retrospective review of UC or IBD unspecified (IBDU) patients who underwent TPC with IPAA for refractory disease or dysplasia between 2008 and 2017. Pouchoscopy data were used to calculate rates of inflammatory pouch conditions. Factors associated with outcomes in univariable analysis were investigated in multivariable analysis. RESULTS: Of the 621 patients more than 18 years of age who underwent TPC with IPAA between January 2008 and December 2017, pouchoscopy data were available for 386 patients during a median follow-up period of 4 years. Acute pouchitis occurred in 205 patients (53%), 60 of whom (30%) progressed to chronic pouchitis. Cuffitis and Crohn's disease-like condition (CDLC) of the pouch occurred in 119 (30%) patients and 46 (12%) patients, respectively. In multivariable analysis, female sex was associated with a decreased risk of acute pouchitis, and pre-operative steroid use and medically refractory disease were associated with an increased risk; IBDU was associated with chronic pouchitis; rectal cuff length ≥2 cm and medically refractory disease were associated with cuffitis; age 45-54 at colectomy was associated with CDLC. Rates of pouch failure were similar in chronic pouchitis and CDLC patients treated with biologics and those who were not. CONCLUSIONS: Inflammatory pouch conditions are common. Biologic use for chronic pouchitis and CDLC does not impact the rate of pouch failure.
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Colite Ulcerativa/cirurgia , Bolsas Cólicas/efeitos adversos , Pouchite/etiologia , Proctocolectomia Restauradora/efeitos adversos , Adulto , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pouchite/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Falha de TratamentoRESUMO
INTRODUCTION: The true incidence of Clostridioides difficile infection (CDI) in patients with an ileal pouch is unknown, and there is little published on its associated risk factors. OBJECTIVE: We aimed to evaluate the rate and risk factors of CDI in pouch patients. METHODS: This was a retrospective review conducted at a single tertiary care inflammatory bowel disease (IBD) center. All ulcerative colitis or IBD-unspecified (IBD-U) patients who underwent total proctocolectomy with ileal pouch anal anastomosis for medically refractory disease or dysplasia between 2008 and 2017 were identified. Symptomatic patients tested for CDI were included. Demographic, disease, and surgical characteristics were collected. Nonparametric methods were used to compare continuous outcomes, and χ2 and Fisher's exact tests were used to compare patients with and without CDI as appropriate. RESULTS: A total of 154 pouch patients had postoperative C. difficilestool testing for symptoms of fever, urgency, increased stool frequency, hematochezia, incontinence, and abdominal and/or pelvic pain. CDI was diagnosed in 11 (7.1%) patients a median of 139 days (IQR 34-1,170) after the final surgical stage. Ten patients (90.9%) received oral vancomycin for 10 days and 1 patient (9.1%) received oral metronidazole for 2 weeks. Ten patients (90.9%) reported improvement in symptoms at completion of therapy. Nine patients (81.8%) were retested for CDI for recurrent symptoms and found to be negative. No patient had CDI recurrence. There was no significant difference in demographic and surgical characteristics, previous antibiotic or proton pump inhibitor use, or previous hospital admission among the patients with and without CDI. CONCLUSIONS: CDI is a rare cause of infectious pouchitis and treatment with oral vancomycin improves symptoms.
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BACKGROUND: The significance of endoscopic activity in asymptomatic ulcerative colitis (UC) patients with an ileal pouch is unknown. AIM: To investigate the association of endoscopic pouch activity in asymptomatic patients with the subsequent development of pouchitis. METHODS: We analyzed a retrospective cohort of patients with UC or IBD-unspecified who underwent a total proctocolectomy with ileal pouch anal anastomosis (IPAA). Asymptomatic patients with a Pouchitis Disease Activity Index (PDAI) symptom sub-score of zero who underwent an index surveillance pouchoscopy were included. Endoscopic pouch body activity was graded as 0: normal, 1: mucosal inflammation, or 2: mucosal breaks (ulcers and/or erosions). The primary outcome was primary acute idiopathic pouchitis defined as PDAI score ≥ 7 with symptoms lasting less than four weeks and responsive to standard antibiotics, not otherwise meeting criteria for secondary pouchitis. The secondary outcome was chronic idiopathic pouchitis defined as PDAI score ≥ 7 with symptoms lasting greater than four weeks despite standard antibiotics. Predictors of pouchitis were analyzed using Kaplan-Meier and Cox regression methods with hazard ratios (HR) and 95% confidence intervals (CI) reported. RESULTS: 143 asymptomatic pouch patients were included. Index endoscopic pouch body activity was 0 in 86 (60.1%) patients, 1 in 26 (18.2%) and 2 in 31 (21.7%). The median length of follow-up after index surveillance pouchoscopy was 3.03 [IQR 1.24-4.60] years. Primary acute idiopathic pouchitis occurred in 44 (31%) patients and chronic idiopathic pouchitis in 12 (8.4%). Grade 2 endoscopic pouch activity was associated with the development of acute pouchitis (HR 2.39, 95% CI 1.23-4.67), although not chronic pouchitis (HR 1.76, 95% CI 0.53-5.87). Histologic inflammation in endoscopically normal pouch mucosa was not associated with acute or chronic pouchitis. CONCLUSIONS: Mucosal breaks are present in nearly a quarter of asymptomatic patients with IPAA and are associated with an increased risk of acute pouchitis.
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Bolsas Cólicas , Endoscopia/efeitos adversos , Pouchite/etiologia , Adulto , Colite Ulcerativa/diagnóstico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , RiscoRESUMO
In a retrospective study of 412 patients with ulcerative colitis who underwent total proctocolectomy with ileal pouch anal anastomosis and had subsequent pouchoscopy, low 25-hydroxyvitamin D was common and was not significantly associated with age, sex, ethnicity, or precolectomy medication use.
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Colite Ulcerativa , Bolsas Cólicas , Pouchite , Proctocolectomia Restauradora , Deficiência de Vitamina D , Humanos , Proctocolectomia Restauradora/efeitos adversos , Colite Ulcerativa/cirurgia , Pouchite/etiologia , Anastomose Cirúrgica/efeitos adversos , Deficiência de Vitamina D/complicações , Bolsas Cólicas/efeitos adversos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Resultado do TratamentoRESUMO
Fertilization is a conserved process in all sexually reproducing organisms whereby sperm bind and fuse with oocytes. Despite the importance of sperm-oocyte interactions in fertilization, the molecular underpinnings of this process are still not well understood. The only cognate ligand-receptor pair identified in the context of fertilization is sperm-surface Izumo and egg-surface Juno in the mouse [1]. Here we describe a genetic screening strategy to isolate fertilization mutants in Caenorhabditis elegans in order to generate a more complete inventory of molecules required for gamete interactions. From this screening strategy, we identified, cloned, and characterized spe-45, a gene that encodes an Izumo-like immunoglobulin superfamily protein. Mammalian Izumo is required for male fertility and has the same basic mutant phenotype as spe-45. Worms lacking spe-45 function produce morphologically normal and motile sperm that cannot fuse with oocytes despite direct contact in the reproductive tract. The power of this screen to identify proteins with ancient sperm functions suggests that characterization of additional mutants from our screen may reveal other deeply conserved components in fertility pathways and complement studies in other organisms.