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BACKGROUND AND OBJECTIVES: The Dysfunctional Voiding and Incontinence Scoring System (DVISS) is a validated tool to evaluate lower urinary tract dysfunction (LUTD) severity in children. DVISS provides a quantitative score (0-35) including a quality-of-life measure, with higher values indicating more/worse symptoms. Clinically, variability exists in symptom severity when patients present to pediatric urology with LUTD. We hypothesized that symptom severity at consultation varied based on race, gender, and/or socioeconomic status. METHODS: All urology encounters at a single institution with completed modified DVISS scores 6/2015-3/2018 were reviewed. Initial visits for patients 5-21 years old with non-neurogenic LUTD were included. Patients with neurologic disorders or genitourinary tract anomalies were excluded. Wilcoxon rank sum tests compared scores between White and Black patients and between male and female patients. Multiple regression models examined relationships among race, gender, estimated median household income, and insurance payor type. All statistics were performed using Stata 15. RESULTS: In total, 4086 initial patient visits for non-neurogenic LUTD were identified. Median DVISS scores were higher in Black (10) versus White (8) patients (p < 0.001). Symptom severity was higher in females (9) versus males (8) (p < 0.001). When estimated median income and insurance payer types were introduced into a multiple regression model, race, gender, and insurance payer type were significantly associated with symptom severity at presentation. CONCLUSIONS: Race, gender, and socioeconomic status significantly impact LUTS severity at the time of urologic consultation. Future studies are needed to clarify the etiologies of these disparities and to determine their clinical significance.
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Síntomas del Sistema Urinario Inferior , Calidad de Vida , Derivación y Consulta , Determinantes Sociales de la Salud , Trastornos Urinarios , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Adulto Joven , Población Negra , Clase Social , Trastornos Urinarios/diagnóstico , Síntomas del Sistema Urinario Inferior/diagnóstico , Factores Sexuales , Factores Raciales , Negro o Afroamericano , Blanco , Índice de Severidad de la Enfermedad , Factores SocioeconómicosRESUMEN
PURPOSE: Patients with spina bifida require urologic follow up with assessments of bladder and renal function. The ideal screening protocol for bladder compliance remains controversial. This study assessed associations between bladder end filling pressure (EFP) and detrusor leak point pressure (DLPP) on urodynamic studies (UDS) and findings from renal bladder ultrasounds (RBUS) and voiding cystourethrograms (VCUG). METHODS: Pediatric spina bifida patients who underwent RBUS and/or VCUG within six months of UDS at a single institution from 2015 to 2021 were retrospectively reviewed. Demographics, VCUG and RBUS results, and UDS EFP and DLPP were recorded. Multiple linear regression analyses and Pearson chi-square tests were conducted to correlate RBUS and VCUG findings with DLPP/EFP. RESULTS: 129 patients were included. In adjusted analyses, moderate to severe hydronephrosis on RBUS was significantly associated with elevations in mean DLPP/EFP (p = 0.006). Patients with round bladders had significantly lower mean DLPP/EFP than patients with elongated or conical bladders (p < 0.0001). The presence of trabeculations was associated with increased mean DLPP/EFP (p < 0.0001) and increases in severity of trabeculations were associated with higher DLPP/EFP (p < 0.0001). The presence of vesicoureteral reflux (VUR) on VCUG was not associated with significant differences in mean DLPP/EFP (p = 0.20). CONCLUSIONS: Abnormal bladder shape and trabeculations on VCUGs in spina bifida patients had significant associations with increased mean bladder pressures on UDS. Assessment of bladder shape and contour by VCUG may be a valuable screening tool in conjunction with routine RBUS in determining the need for further assessment of bladder pressures in patients with spina bifida.
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Disrafia Espinal , Vejiga Urinaria Neurogénica , Reflujo Vesicoureteral , Humanos , Niño , Estudios Retrospectivos , Vejiga Urinaria/diagnóstico por imagen , Disrafia Espinal/complicaciones , Disrafia Espinal/diagnóstico por imagen , Vejiga Urinaria Neurogénica/diagnóstico por imagen , Vejiga Urinaria Neurogénica/etiología , Reflujo Vesicoureteral/complicaciones , Reflujo Vesicoureteral/diagnóstico por imagen , UrodinámicaRESUMEN
Persistent anhydramnios after placement of a vesicoamniotic shunt is a rare but potentially serious concern in a patient in utero. We present the case a male fetus who at 32-week gestation had bilateral hydroureteronephrosis, a distended bladder, and anhydramnios. A vesicoamniotic shunt was placed, but the anhydramnios persisted. Postnatally, the child was found to have a migrated shunt, left grade V vesicoureteral reflux and posterior urethral valves. He underwent a posterior urethral valves ablation and removal of the migrated shunt. The patient is now 2 years old and is doing well with no urinary tract infections or renal deterioration.
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Enfermedades Fetales , Enfermedades Uretrales , Obstrucción Uretral , Niño , Preescolar , Femenino , Enfermedades Fetales/cirugía , Humanos , Masculino , Embarazo , Resultado del Tratamiento , Ultrasonografía Prenatal , Obstrucción Uretral/etiología , Obstrucción Uretral/cirugíaRESUMEN
OBJECTIVE: To explore the long-term outcomes and indications for cystectomy in patients with bladder exstrophy. Although rare, cystectomy is the final surgical alternative to bladder repair among these patients with a poor quality bladder template. METHODS: A prospectively maintained database of 1298 patients with exstrophy-epispadias complex was reviewed for patients who underwent cystectomy between 1970 and 2015 at the authors' institution. Demographic data, indication for cystectomy, surgical history, postoperative outcomes, and continence status were collected. RESULTS: Eighteen (6 male; 12 female) patients with exstrophy (15 classic bladder exstrophy; 2 bladder exstrophy variants; 1 cloacal exstrophy) underwent cystectomy at a median age of 3.8 years. Six patients (33.3%) underwent primary cystectomy without attempted bladder closure. Eight patients (44.4%) had a history of failed primary closure with loss of capacity or inadequate growth after closure. Four patients (22.2%) had successful primary closure but underwent cystectomy secondary to poor bladder compliance with declining renal function or poor bladder growth or quality. Urinary diversion included 6 cutaneous ureterostomies, 4 bowel conduits (1 ileal; 3 colon), 6 continent urinary diversions with ileosigmoid reservoir, and 1 ureterosigmoidostomy. Of 8 patients who underwent a continence procedure, all were dry at a median of 25.3 months after cystectomy. CONCLUSION: Cystectomy was most commonly indicated in intrinsically diseased bladder templates that remained too small despite permitting time for interval growth. These bladders often were of poor quality and compliance and did not reduce into the pelvis on examination. It was, however, possible to achieve urinary continence in these patients with cystectomy and urinary diversion.
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Extrofia de la Vejiga/cirugía , Cistectomía/efectos adversos , Epispadias/cirugía , Derivación Urinaria/estadística & datos numéricos , Incontinencia Urinaria/epidemiología , Adolescente , Extrofia de la Vejiga/complicaciones , Extrofia de la Vejiga/fisiopatología , Niño , Preescolar , Epispadias/complicaciones , Epispadias/fisiopatología , Femenino , Humanos , Lactante , Masculino , Estudios Prospectivos , Reoperación/estadística & datos numéricos , Estudios Retrospectivos , Vejiga Urinaria/anomalías , Vejiga Urinaria/fisiopatología , Vejiga Urinaria/cirugía , Derivación Urinaria/métodos , Incontinencia Urinaria/etiología , Incontinencia Urinaria/fisiopatologíaRESUMEN
INTRODUCTION: To date, the ergonomics of flexible ureteroscopy (URS) have not been well described. We performed a study to assess the biomechanical stresses on urologists performing URS and to investigate the effect of ureteroscope type on these parameters. METHODS: Electromyography (EMG) was used to quantify the activation level of muscle groups involved in URS. Surface EMG electrodes (Delsys, Boston, MA) were placed on the right and left thenar, flexor carpi ulnaris (FCU), extensor carpi ulnaris (ECU), biceps, triceps, and deltoid. Three endoscopes were studied: single-use digital (Boston Scientific LithoVue), reusable digital (Karl Storz Flex-Xc), and reusable fiber-optic (Karl Storz Flex-X2). Each ureteroscope was used to perform a set sequence of navigation and procedural tasks in a training model. EMG data were processed and normalized to compare the maximum voluntary contractions between muscle groups. Cumulative muscular workload (CMW) and average muscular work per second (AWS) were used for comparative analysis. RESULTS: For navigational tasks, CMW and AWS were greatest for the ECU, followed in descending order by right and left thenar, FCU, biceps, deltoid, and triceps. For procedural tasks, CMW and AWS were greatest for the right thenar, followed in descending order by the left thenar, ECU, FCU, triceps, biceps, and deltoid. During navigational tasks, both LithoVue and Flex-Xc had lower CMWs for every muscle group than Flex-X2 (p < 0.05). LithoVue and Flex-Xc had similar AWS and both were lower than Flex-X2 for the right thenar, ECU, biceps, and deltoid activation (p < 0.05). During procedural tasks, both LithoVue and Flex-Xc had lower CMWs and AWS for right and left thenar, ECU, and biceps than Flex-X2 (p < 0.05). CONCLUSIONS: This study provides the first description of EMG-measured ergonomics of URS. Both the single-use and reusable digital ureteroscopes have similar profiles, and both have significantly better ergonomic metrics than the reusable fiber-optic ureteroscope.
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Ergonomía/normas , Músculo Esquelético/fisiología , Ureteroscopios/normas , Ureteroscopía/instrumentación , Brazo/fisiología , Fenómenos Biomecánicos , Electromiografía , Tecnología de Fibra Óptica , Humanos , Estrés Fisiológico/fisiologíaRESUMEN
PURPOSE: To determine the impact of lymph node density (LND) on survival after inguinal lymph node dissection (ILND) for penile cancer. MATERIALS AND METHODS: Our institutional penile cancer database was queried for patients who underwent ILND. Clinicopathologic characteristics including LND and total number of positive lymph nodes (LNs) were analyzed to determine impact on recurrence-free survival (RFS) and overall survival (OS). LND, or the percent of positive LN out of total LN, was calculated as a categorical variable at varying thresholds. RESULTS: Twenty-eight patients with complete follow-up were identified. Indications for ILND were stage >T2 in 20 patients (71.4%), palpable adenopathy in 7 (25%), high grade T1 in 1 (3.6%). Median node yield was 17.5 (interquartile range, 12-22), and positive LNs were found in 14 patients (50%). RFS and OS were significantly lower for patients with >15% LN density (median RFS: 62 months vs. 6.3 months, p=0.0120; median OS: 73.6 months vs. 6.3 months, p<0.001). Controlling for age, medical comorbidities, number of positive LN, T stage, pelvic LN status and indication, LN density >15% was independently associated with worse RFS (hazard ratio [HR], 3.6; p=0.04) and OS (HR, 73.6; p=0.002). The c-index for LND was higher than total positive LNs for RFS (0.64 vs. 0.54) and OS (0.79 vs. 0.61). CONCLUSIONS: In this small, retrospective penile cancer cohort, the presence of nodal involvement >15% was associated with decreased RFS and OS, and outperformed total number of positive LN as a prognostic indicator.
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Escisión del Ganglio Linfático , Ganglios Linfáticos/patología , Neoplasias del Pene/patología , Neoplasias del Pene/cirugía , Anciano , Supervivencia sin Enfermedad , Humanos , Conducto Inguinal , Ganglios Linfáticos/cirugía , Metástasis Linfática , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Estudios Retrospectivos , Tasa de SupervivenciaRESUMEN
INTRODUCTION: In response to the 2011 Accreditation Council for Graduate Medical Education duty hour restrictions, many residency programs adopted a night float system. Due to concerns regarding the effects of night float on sleep and subsequently on patient care, we examined sleep patterns of residents on different call schedules. METHODS: Urology residents assigned to day shift (Monday-Friday, 6am-6pm), night float (Sunday-Friday, 6pm-6am) or 24-hour home call and attending physicians were monitored for two-week periods using actigraphy bands. Total sleep time, light versus deep sleep time, sleep latency and number of sleep disruptions were measured. Comparative statistics and logistic regression were used to compare call systems and to determine predictors of sleep metrics. RESULTS: When comparing day shift, night float, and 24-hour home call, the only significant difference was in sleep latency. All sleep variables except sleep latency were significantly different among residents of various levels (junior, senior, research year). Compared to residents, attendings had shorter sleep latency and were woken less frequently. Being a research year resident was the only significant univariate predictor of total sleep. Age and being a research year resident were significant univariate predictors of sleep latency. CONCLUSIONS: This pilot study demonstrates the feasibility of actigraphy in measuring sleep patterns of urology house officers. It also suggests that night float does not significantly impact total sleep or quality of sleep. Further research is needed to confirm these findings and to determine the effects of night float rotations on resident quality of life and patient safety.
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Bladder exstrophy and cloacal exstrophy are rare congenital defects of the genitourinary tract that require complex surgical reconstruction. Malrotation of the bony pelvis causes a characteristic diastasis of the pubic symphysis, which is surgically reduced at the time of initial bladder closure. For a successful primary closure without tension such that the bladder can be placed deep within the pelvis, pelvic osteotomy is often used. However, alternative techniques have been utilized to bring the pubic rami into apposition. The authors present four bladder/cloacal exstrophy patients in which an intrapubic wire was used for pubic apposition, resulting in significant genitourinary complications.
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Hilos Ortopédicos/efectos adversos , Osteotomía , Complicaciones Posoperatorias , Diástasis de la Sínfisis Pubiana , Suturas/efectos adversos , Procedimientos Quirúrgicos Urológicos , Extrofia de la Vejiga , Niño , Preescolar , Cloaca/anomalías , Femenino , Humanos , Lactante , Masculino , Osteotomía/efectos adversos , Osteotomía/métodos , Huesos Pélvicos/cirugía , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/cirugía , Diástasis de la Sínfisis Pubiana/etiología , Diástasis de la Sínfisis Pubiana/cirugía , Procedimientos de Cirugía Plástica/efectos adversos , Procedimientos de Cirugía Plástica/métodos , Reimplantación/métodos , Resultado del Tratamiento , Procedimientos Quirúrgicos Urológicos/efectos adversos , Procedimientos Quirúrgicos Urológicos/métodosRESUMEN
PURPOSE: The authors have reviewed the use of muscle pedicle flaps for the treatment of failed bladder neck closure in exstrophy spectrum patients. METHODS: A retrospective review of all exstrophy spectrum patients who underwent continence procedures with the use of muscle pedicle flaps at our institution during the last 15 years was performed. Patient characteristics, surgical history, and outcomes, including complications, continence, morbidity, and infection, were assessed. The authors utilized muscle pedicle flaps in eight exstrophy patients, including four patients with classic bladder exstrophy and four patients with cloacal exstrophy. Seven of eight patients had failed at least one prior bladder neck closure, and they had undergone a median of three prior urologic procedures. To achieve continence, five rectus muscle flaps and three gracilis muscle flaps were utilized in combination with bladder neck closure. RESULTS: There were no major intraoperative or postoperative complications. All patients were initially continent, and after a median follow-up of 18.7 months seven of eight patients were continent. One patient required continent urinary stoma revision and one patient developed perineal incontinence after perineal trauma. No patients required revision of, or additional, continence procedures at the bladder neck. DISCUSSION: The use of pedicle muscle flaps appears to be a safe and feasible option for exstrophy spectrum patients with failed bladder neck closure. Although achieving continence can be difficult in this population, use of muscle flaps and bladder neck closure is a viable and effective option in this challenging subset of patients.
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Extrofia de la Vejiga/cirugía , Colgajos Quirúrgicos , Niño , Humanos , Masculino , Recto del Abdomen/trasplante , Estudios Retrospectivos , Procedimientos Quirúrgicos Urológicos/métodosRESUMEN
OBJECTIVE: To analyze variability in urologists' Medicare utilization and payment and estimate potential cost savings of standardized service utilization using information from the recently released Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File (PUF) and to highlight potential limitations of PUF analysis. MATERIALS AND METHODS: The Centers for Medicare and Medicaid Services just released the PUF with payment or utilization data for 8792 urologists participating in Medicare in 2012. Linear regression correlated total number of patient visits with total Medicare payments to each urologist. Physicians were categorized into quartiles by actual payment in excess of predicted payment modeled by this regression. Utilization variability was calculated as a relative risk for the 40 most highly reimbursed services per patient visit, comparing the highest vs lowest quartile of urologists. Potential cost savings for those 40 services were calculated if services per visit >50% above the median were eliminated. RESULTS: Medicare reimbursement was strongly predicted by the number of patient visits (R(2) = 0.70). Utilization variability of services performed per visit had a relative risk up to 3.52. The potential cost savings was $125,199,007 (9.0% of total 2012 Medicare urologist reimbursements). CONCLUSION: Overall Medicare payment to urologists was strongly predicted by number of patient visits. Substantial variability existed in utilization of services per patient visit. Standardized utilization may result in significant Medicare cost savings. However, future analyses accounting for variable patient characteristics are needed to accurately determine appropriate service utilization.
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Medicare/economía , Medicare/estadística & datos numéricos , Mecanismo de Reembolso/estadística & datos numéricos , Urología/economía , Urología/estadística & datos numéricos , Ahorro de Costo , Gastos en Salud , Humanos , Estados UnidosRESUMEN
OBJECTIVE: The present study is designed to assess the long-term renal function of children who underwent radical nephrectomy for unifocal Wilms tumor. METHODS: A single institution retrospective cohort study of non-syndromic children treated with radical nephrectomy for unifocal Wilms tumor between 1995 and 2011 was performed to identify risk factors for decreased glomerular filtration rate (GFR). The primary endpoint was decrease in age-adjusted GFR below normal published ranges. The secondary endpoint was progression to chronic renal insufficiency (CRI). RESULTS: A total of 55 patients were identified in the cohort. Eight (15%) patients exhibited decreased age-adjusted GFR during the follow-up period, with 2 (4%) progressing to CRI. Increasing time between surgery and the last known GFR follow-up was associated with decreased GFR, with the normal GFR group having median follow-up of 7.32 years versus 11.47 years (p = 0.019) in the decreased GFR group. CONCLUSIONS: A trend toward decline in GFR was detected with longer follow-up. Longer follow-up may reveal that clinically significant decline in renal function occurs years following nephrectomy among a subset of Wilms tumor survivors, even among those who do not progress to end stage renal disease.
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Neoplasias Renales/cirugía , Nefrectomía , Insuficiencia Renal Crónica/epidemiología , Tumor de Wilms/cirugía , Adolescente , Niño , Preescolar , Femenino , Tasa de Filtración Glomerular/fisiología , Humanos , Neoplasias Renales/patología , Neoplasias Renales/fisiopatología , Masculino , Estudios Retrospectivos , Factores de Riesgo , Factores de Tiempo , Tumor de Wilms/patología , Tumor de Wilms/fisiopatología , Adulto JovenRESUMEN
INTRODUCTION AND OBJECTIVE: Staged pelvic osteotomy (SPO) prior to bladder closure has been shown to be a safe and effective method for achieving pubic approximation in cloacal exstrophy (CE) patients with extreme diastasis. However, SPO outcomes have never been compared to those for combined pelvic osteotomy (CPO) at the time of closure in CE patients. METHODS: A prospectively maintained database of 1208 exstrophy-epispadias complex patients was reviewed for CE patients treated with pelvic osteotomies. Inclusion criteria were osteotomy at the authors' institution and closure within two months of osteotomy. After inclusion, patients were separated into four groups depending on osteotomy procedure (SPO vs. CPO) and whether their osteotomy occurred with primary closure or re-closure. Patient demographics, closure history, pre-operative diastasis measurement, most recent post-operative diastasis measurement, and outcomes were recorded and compared by chi-squared tests and ANOVA. RESULTS: Among 116 CE patients reviewed, 46 met inclusion criteria. With primary closure or re-closure, 27 had SPO and 19 had CPO. No SPO re-closure patients had previous osteotomy; 4 CPO re-closure patients had a previous osteotomy with closure. Median time between osteotomy and closure in SPO patients was 14 days. Median follow-up after SPO and CPO were 4 and 11 years, respectively. SPO significantly reduced the pre-operative diastasis compared to CPO on most recent diastasis measurement (3.5 cm vs. 0.4 cm, p=0.003). There were no significant differences in the overall complication rate, or the rates of each specific complication, between the SPO and CPO groups. No patients had wound dehiscence or prolapse. One CPO patient was able to intermittently catheterize per urethra while all other patients required continent urinary diversion to achieve continence. CONCLUSIONS: To the authors' knowledge, this is the first study comparing SPO and CPO outcomes in CE patients. SPO reduces pre-operative diastasis more than CPO, and does not appear to incur increased rates of complication, closure failure, or incontinence. Due to its apparent safety and greater efficacy, SPO should be considered in all CE patients with extreme diastases undergoing primary closure or re-closure.
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Extrofia de la Vejiga/cirugía , Osteotomía/métodos , Diástasis de la Sínfisis Pubiana/cirugía , Procedimientos Quirúrgicos Urológicos Masculinos/métodos , Adolescente , Niño , Preescolar , Humanos , Lactante , Masculino , ReoperaciónRESUMEN
Bladder exstrophy is a rare birth defect that typically requires patients to undergo multiple surgical procedures throughout the course of their childhood. Many ultimately undergo operations that use segments of bowel for the reconstruction and/or augmentation of the urinary tract, which imparts an increased risk of malignancy in these patients. We present the case of a 59-year-old man with a history of bladder exstrophy managed with ureterosigmoidostomies revised to an ileal conduit who developed a large adenocarcinoma in the ileal conduit that extended into small bowel, sigmoid colon, and ureter.
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UNLABELLED: What's known on the subject? and What does the study add? The Epstein criteria, which utilize prostate specific antigen density (PSAD) benchmarks, are recognized to be a reasonable method of selecting men for active surveillance of prostate cancer. Transrectal ultrasonography, however, may not be a sufficiently precise method of measuring prostate volume for the determination of PSAD. This study shows that despite impressive intra-observer variability in transrectal ultrasonography guided prostate volume measurements, this variability typically does not affect the PSAD to an extent by which qualification for active surveillance would be altered. OBJECTIVE: ⢠To determine intra-observer variability in transrectal ultrasonography (TRUS) guided prostate volume measurements in the Johns Hopkins active surveillance group and to establish whether or not this variability could affect prostate-specific antigen density (PSAD) estimates in this cohort. PATIENTS AND METHODS: ⢠In all, 253 patients with a combined total of 1111 prostate biopsies underwent TRUS-guided prostate volume measurements performed by the same physician at least three times over the course of their care. ⢠Coefficients of variation (CV) were calculated for each set of measurements performed on each patient by the same physician, and average CVs were determined for each physician and for physicians overall. The CVs were correlated with the average of each patient's measured prostate volumes to look for any trend. ⢠Finally, measured prostate volumes were used with each patient's initial prostate-specific antigen (PSA) value to calculate PSAD to reveal whether or not the degree of variability found in these measurements would have led to PSADs that would have otherwise precluded qualification for active surveillance. RESULTS: ⢠The average CV for all sets of prostate volume data was 0.168. Average CVs for each physician ranged from 0.136 to 0.234. ⢠However, actual CVs ranged anywhere from 0.013 to 0.549. The CVs were found to have no correlation with prostate volumes (Pearson correlation coefficient: 0.04). ⢠In 95% of cases, variability in TRUS-guided prostate volume measurement did not affect PSAD sufficiently to elicit a value greater than 0.15. CONCLUSIONS: ⢠Even among individuals who are highly experienced in TRUS-guided prostate volume measurement, significant intra-observer variation exists. However, this variability is not enough to affect one's eligibility for prostate cancer active surveillance when PSAD criteria are used. ⢠The TRUS-guided prostate volume measurements remain a reliable method of assessing PSAD in patients with prostate cancer.
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Antígeno Prostático Específico/metabolismo , Próstata/patología , Neoplasias de la Próstata/diagnóstico , Anciano , Biopsia/métodos , Estudios de Cohortes , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Tamaño de los Órganos , Selección de Paciente , Próstata/metabolismo , Ultrasonografía Intervencional/métodosRESUMEN
Detection of nucleic acids and induction of type I interferons (IFNs) are principal elements of antiviral defense but can cause autoimmunity if misregulated. Cytosolic DNA detection activates a potent, cell-intrinsic antiviral response through a poorly defined pathway. In a screen for proteins relevant to this IFN-stimulatory DNA (ISD) response, we identify 3' repair exonuclease 1 (Trex1). Mutations in the human trex1 gene cause Aicardi-Goutieres syndrome (AGS) and chilblain lupus, but the molecular basis of these diseases is unknown. We define Trex1 as an essential negative regulator of the ISD response and delineate the genetic pathway linking Trex1 deficiency to lethal autoimmunity. We show that single-stranded DNA derived from endogenous retroelements accumulates in Trex1-deficient cells, and that Trex1 can metabolize reverse-transcribed DNA. These findings reveal a cell-intrinsic mechanism for initiation of autoimmunity, implicate the ISD pathway as the cause of AGS, and suggest an unanticipated contribution of endogenous retroelements to autoimmunity.