Factors associated with successful liberation from continuous renal replacement therapy in children and young adults: analysis of the worldwide exploration of renal replacement outcomes collaborative in Kidney Disease Registry.

PURPOSE: Continuous renal replacement therapy (CRRT) is used for supportive management of acute kidney injury (AKI) and disorders of fluid balance (FB). Little is known about the predictors of successful liberation in children and young adults. We aimed to identify the factors associated with successful CRRT liberation. METHODS: The Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease study is an international multicenter retrospective study (32 centers, 7 nations) conducted from 2015 to 2021 in children and young adults (aged 0-25 years) treated with CRRT for AKI or FB disorders. Patients with previous dialysis dependence, tandem extracorporeal membrane oxygenation use, died within the first 72 h of CRRT initiation, and those who never had liberation attempted were excluded. Patients were categorized based on first liberation attempt: reinstituted (resumption of any dialysis within 72 h) vs. success (no receipt of dialysis for ≥ 72 h). Multivariable logistic regression was used to identify factors associated with successful CRRT liberation. RESULTS: A total of 622 patients were included: 287 (46%) had CRRT reinstituted and 335 (54%) were successfully liberated. After adjusting for sepsis at admission and illness severity parameters, several factors were associated with successful liberation, including higher VIS (vasoactive-inotropic score) at CRRT initiation (odds ratio [OR] 1.35 [1.12-1.63]), higher PELOD-2 (pediatric logistic organ dysfunction-2) score at CRRT initiation (OR 1.71 [1.24-2.35]), higher urine output prior to CRRT initiation (OR 1.15 [1.001-1.32]), and shorter CRRT duration (OR 0.19 [0.12-0.28]). CONCLUSIONS: Inability to liberate from CRRT was common in this multinational retrospective study. Modifiable and non-modifiable factors were associated with successful liberation. These results may inform the design of future clinical trials to optimize likelihood of CRRT liberation success.

Major Adverse Kidney Events in Pediatric Continuous Kidney Replacement Therapy.

Importance: Continuous kidney replacement therapy (CKRT) is increasingly used in youths with critical illness, but little is known about longer-term outcomes, such as persistent kidney dysfunction, continued need for dialysis, or death. Objective: To characterize the incidence and risk factors, including liberation patterns, associated with major adverse kidney events 90 days after CKRT initiation (MAKE-90) in children, adolescents, and young adults. Design, Setting, and Participants: This international, multicenter cohort study was conducted among patients aged 0 to 25 years from The Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK) registry treated with CKRT for acute kidney injury or fluid overload from 2015 to 2021. Exclusion criteria were dialysis dependence, concurrent extracorporeal membrane oxygenation use, or receipt of CKRT for a different indication. Data were analyzed from May 2 to December 14, 2023. Exposure: Patient clinical characteristics and CKRT parameters were assessed. CKRT liberation was classified as successful, reinstituted, or not attempted. Successful liberation was defined as the first attempt at CKRT liberation resulting in 72 hours or more without return to dialysis within 28 days of CKRT initiation. Main Outcomes and Measures: MAKE-90, including death or persistent kidney dysfunction (dialysis dependence or ≥25% decline in estimated glomerular filtration rate from baseline), were assessed. Results: Among 969 patients treated with CKRT (529 males [54.6%]; median [IQR] age, 8.8 [1.7-15.0] years), 630 patients (65.0%) developed MAKE-90. On multivariable analysis, cardiac comorbidity (adjusted odds ratio [aOR], 1.60; 95% CI, 1.08-2.37), longer duration of intensive care unit admission before CKRT initiation (aOR for 6 days vs 1 day, 1.07; 95% CI, 1.02-1.13), and liberation pattern were associated with MAKE-90. In this analysis, patients who successfully liberated from CKRT within 28 days had lower odds of MAKE-90 compared with patients in whom liberation was attempted and failed (aOR, 0.32; 95% CI, 0.22-0.48) and patients without a liberation attempt (aOR, 0.02; 95% CI, 0.01-0.04). Conclusions and Relevance: In this study, MAKE-90 occurred in almost two-thirds of the population and patient-level risk factors associated with MAKE-90 included cardiac comorbidity, time to CKRT initiation, and liberation patterns. These findings highlight the high incidence of adverse outcomes in this population and suggest that future prospective studies are needed to better understand liberation patterns and practices.

Fluid Balance and Its Association With Mortality and Health-Related Quality of Life: A Nonprespecified Secondary Analysis of the Life After Pediatric Sepsis Evaluation.

OBJECTIVES: To evaluate the association between fluid balance (FB) and health-related quality of life (HRQL) among children at 1 month following community-acquired septic shock. DESIGN: Nonprespecified secondary analysis of the Life After Pediatric Sepsis Evaluation. FB was defined as 100 × [(cumulative PICU fluid input - cumulative PICU fluid output)/PICU admission weight]. Three subgroups were identified: low FB (< 5%), medium FB (5%-15%), and high FB (> 15%) based on cumulative FB on days 0-3 of ICU stay. HRQL was measured at ICU admission and 1 month after using Pediatric Quality of Life Inventory 4.0 Generic Core or Infant Scales or the Stein-Jessop Functional Status Scale. The primary outcome was a composite of mortality or greater than 25% decline in HRQL 1 month after admission compared with baseline. SETTING: Twelve academic PICUs in the United States. PATIENTS: Critically ill children between 1 month and 18 years, with community-acquired septic shock who survived to at least day 4. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two hundred ninety-three patients were included of whom 66 (23%) had low FB, 127 (43%) had medium FB, and 100 (34%) had high FB. There was no difference in Pediatric Risk of Mortality Score 3 (median 11 [6, 17]), age (median 5 [1, 12]), or gender (47% female) between FB groups. After adjusting for potential confounders and comparing with medium FB, higher odds of mortality or greater than 25% HRQL decline were seen in both the low FB (odds ratio [OR] 2.79 [1.20, 6.57]) and the high FB (OR 2.16 [1.06, 4.47]), p = 0.027. Compared with medium FB, low FB (OR 4.3 [1.62, 11.84]) and high FB (OR 3.29 [1.42, 8.00]) had higher odds of greater than 25% HRQL decline. CONCLUSIONS: Over half of the children who survived septic shock had low or high FB, which was associated with a significant decline in HRQL scores. Prospective studies are needed to determine if optimization of FB can improve HRQL outcomes.

The complement system in pediatric acute kidney injury.

The complement cascade is an important part of the innate immune system. In addition to helping the body to eliminate pathogens, however, complement activation also contributes to the pathogenesis of a wide range of kidney diseases. Recent work has revealed that uncontrolled complement activation is the key driver of several rare kidney diseases in children, including atypical hemolytic uremic syndrome and C3 glomerulopathy. In addition, a growing body of literature has implicated complement in the pathogenesis of more common kidney diseases, including acute kidney injury (AKI). Complement-targeted therapeutics are in use for a variety of diseases, and an increasing number of therapeutic agents are under development. With the implication of complement in the pathogenesis of AKI, complement-targeted therapeutics could be trialed to prevent or treat this condition. In this review, we discuss the evidence that the complement system is activated in pediatric patients with AKI, and we review the role of complement proteins as biomarkers and therapeutic targets in patients with AKI.

Electrolyte derangements in critically ill children receiving balanced versus unbalanced crystalloid fluid resuscitation.

BACKGROUND: Adult studies have demonstrated potential harm from resuscitation with 0.9% sodium chloride (0.9%NaCl), resulting in increased utilization of balanced crystalloids like lactated ringers (LR). The sodium and potassium content of LR has resulted in theoretical safety concerns, although limited data exists in pediatrics. We hypothesized that use of LR for resuscitation would not be associated with increased electrolyte derangements compared to 0.9%NaCl. METHODS: A prospective, observational cohort study of critically ill children who received ≥ 20 ml/kg of fluid resuscitation and were admitted to two pediatric intensive care units from November 2017 to February 2020. Fluid groups included patients who received > 75% of fluids from 0.9%NaCl, > 75% of fluids from LR, and a mixed group. The primary outcome was incidence of electrolyte derangements (sodium, chloride, potassium) and acidosis. RESULTS: Among 559 patients, 297 (53%) received predominantly 0.9%NaCl, 74 (13%) received predominantly LR, and 188 (34%) received a mixture. Extreme hyperkalemia (potassium ≥ 6 mmol/L) was more common in 0.9%NaCl group (5.8%) compared to LR group (0%), p 0.05. Extreme acidosis (pH > 7.1) was more common in 0.9%NaCl group (11%) compared to LR group (1.6%), p 0.016. CONCLUSIONS: LR is associated with fewer electrolyte derangements compared to 0.9%NaCl. Prospective interventional trials are needed to validate these findings.

Decreases in Nephrotoxic Pain Medications Are Not Associated With Increased Opioid Utilization in Critically Ill Children.

OBJECTIVES: Quality improvement initiatives to decrease rates of nephrotoxic medication exposure have reduced rates of acute kidney injury (AKI) in noncritically ill children. The objective of our study was to analyze the implementation of a similar program in critically ill children and to measure important balancing measures including opioid and benzodiazepine exposure. DESIGN: Prospective quality improvement study. SETTING: PICU at Children's Hospital Colorado between 2018 and 2020. PATIENTS: All children admitted to PICU. INTERVENTIONS: Quality improvement initiative called Nephrotoxic Injury Negated by Just-In-Time Action (NINJA). MEASUREMENT AND MAIN RESULTS: Eight thousand eight hundred thirty-three PICU patient admissions were included. Mean rates of nephrotoxic medication exposure/1,000 PICU patient days decreased from 46 to 26, whereas rates of nephrotoxic AKI/1,000 PICU patient days did not change. Nonsteroidal anti-inflammatory drug dispenses per 1,000 patient days were reduced from 521 to 456. Similarly, opioid and benzodiazepine exposures per 1,000 patient days were reduced from 812 to 524 and 441 to 227, respectively, during the study observation period. CONCLUSIONS: The NINJA intervention was efficaciously implemented in our single-center PICU. Nephrotoxic exposure is a modifiable factor that did not inadvertently increase exposure to opioids and benzodiazepines.

A Pilot Study of the Safety and Efficacy of Alkali Therapy on Vascular Function in Kidney Transplant Recipients.

INTRODUCTION: Metabolic acidosis is associated with cardiovascular events, graft function, and mortality in kidney transplant recipients (KTRs). We examined the effect of alkali therapy on vascular endothelial function in KTRs. METHODS: We performed an 18-week, randomized, double-blind, placebo-controlled crossover pilot study examining the effect of sodium bicarbonate therapy versus placebo on vascular function in 20 adult KTRs at least 1 year from transplant with an estimated glomerular filtration rate (eGFR) ≥45 ml/min per 1.73 m2 and a serum bicarbonate level of 20 to 26 mEq/L. Each treatment period was 8 weeks in duration with a 2-week washout period between treatments. The primary outcome was change in brachial artery flow-mediated dilation (FMD) between sodium bicarbonate treatment and placebo. RESULTS: Twenty patients completed the study and were included in the primary analysis. The mean (SD) baseline eGFR of participants was 75 (22) ml/min per 1.73 m2, respectively. Serum bicarbonate levels did not increase significantly with treatment (0.3 [1.5] mEq/L, P = 0.37). Sodium bicarbonate therapy was not associated with worsening blood pressure, weight gain, or hypokalemia. There was no significant increase in FMD after 8 weeks of sodium bicarbonate therapy compared to placebo (mean change in FMD 2.2%, 95% CI -0.1 to 4.6, P = 0.06). There were no significant changes in high-sensitivity C-reactive protein, interleukin-6, eGFR, or urinary albumin-to-creatinine ratio during treatment. Urinary ammonium excretion decreased by 9 mmol/d (P=0.003), with sodium bicarbonate. CONCLUSIONS: Sodium bicarbonate therapy is safe and feasible in KTRs, and our results strengthen the need for a larger randomized controlled trial.

Complement Activation Fragments Are Increased in Critically Ill Pediatric Patients with Severe AKI.

Background: Children who are critically ill with AKI suffer from high morbidity and mortality rates, and lack treatment options. Emerging evidence implicates the role of complement activation in AKI pathogenesis, which could potentially be treated with complement inhibitors. The purpose of this study is to evaluate the association between complement activation fragments and severity of AKI in children who are critically ill. Methods: A biorepository of samples from children who are critically ill from a prior multisite study was leveraged to identify children with stage 3 AKI and matched to patients without AKI on the basis of PELOD-2 (illness severity) scores. Specimens were analyzed for plasma and urine complement activation fragments of factor B, C3a, C4a, and sC5b-9. The primary outcomes were MAKE30 and severe AKI rates. Results: In total, 14 patients with stage 3 AKI (five requiring RRT) were matched to 14 patients without AKI. Urine factor Ba and plasma C4a levels increased stepwise as severity of AKI increased, from no AKI to stage 3 AKI, to stage 3 AKI with RRT need. Plasma C4a levels were independently associated with increased risk of MAKE30 outcomes (OR, 3.2; IQR, 1.1-8.9), and urine Ba (OR, 1.9; IQR, 1.1-3.1), plasma Bb (OR, 2.7; IQR, 1.1-6.8), C4a (OR, 13.0; IQR, 1.6-106.6), and C3a (OR, 3.3; IQR, 1.3-8.4) were independently associated with risk of severe stage 2-3 AKI on day 3 of admission. Conclusions: Multiple complement fragments increase as magnitude of AKI severity increases. Very high levels of urine Ba or plasma C4a may identify patients at risk for severe AKI, hemodialysis, and MAKE30 outcomes. The fragments may be useful as a functional biomarker of complement activation and may identify those patients to study complement inhibition to treat or prevent AKI in children who are critically ill. These findings suggest the need for further specific investigations of the role of complement activation in children who are critically ill and at risk of AKI.

PERSEVERE Biomarkers Predict Severe Acute Kidney Injury and Renal Recovery in Pediatric Septic Shock.

Rationale: Acute kidney injury (AKI), a common complication of sepsis, is associated with substantial morbidity and mortality and lacks definitive disease-modifying therapy. Early, reliable identification of at-risk patients is important for targeted implementation of renal protective measures. The updated Pediatric Sepsis Biomarker Risk Model (PERSEVERE-II) is a validated, multibiomarker prognostic enrichment strategy to estimate baseline mortality risk in pediatric septic shock.Objectives: To assess the association between PERSEVERE-II mortality probability and the development of severe, sepsis-associated AKI on Day 3 (D3 SA-AKI) in pediatric septic shock.Methods: We performed secondary analysis of a prospective observational study of children with septic shock in whom the PERSEVERE biomarkers were measured to assign a PERSEVERE-II baseline mortality risk.Measurements and Main Results: Among 379 patients, 65 (17%) developed severe D3 SA-AKI. The proportion of patients developing severe D3 SA-AKI increased directly with increasing PERSEVERE-II risk category, and increasing PERSEVERE-II mortality probability was independently associated with increased odds of severe D3 SA-AKI after adjustment for age and illness severity (odds ratio, 1.4; 95% confidence interval, 1.2-1.7; P < 0.001). Similar associations were found between increasing PERSEVERE-II mortality probability and the need for renal replacement therapy. Lower PERSEVERE-II mortality probability was independently associated with increased odds of renal recovery among patients with early AKI. A newly derived model incorporating the PERSEVERE biomarkers and Day 1 AKI status predicted severe D3 SA-AKI with an area under the received operating characteristic curve of 0.95 (95% confidence interval, 0.92-0.98).Conclusions: Among children with septic shock, the PERSEVERE biomarkers predict severe D3 SA-AKI and identify patients with early AKI who are likely to recover.

PPARα contributes to protection against metabolic and inflammatory derangements associated with acute kidney injury in experimental sepsis.

Sepsis-associated acute kidney injury (AKI) is a significant problem in critically ill children and adults resulting in increased morbidity and mortality. Fundamental mechanisms contributing to sepsis-associated AKI are poorly understood. Previous research has demonstrated that peroxisome proliferator-activated receptor α (PPARα) expression is associated with reduced organ system failure in sepsis. Using an experimental model of polymicrobial sepsis, we demonstrate that mice deficient in PPARα have worse kidney function, which is likely related to reduced fatty acid oxidation and increased inflammation. Ultrastructural evaluation with electron microscopy reveals that the proximal convoluted tubule is specifically injured in septic PPARα deficient mice. In this experimental group, serum metabolomic analysis reveals unanticipated metabolic derangements in tryptophan-kynurenine-NAD+ and pantothenate pathways. We also show that a subgroup of children with sepsis whose genome-wide expression profiles are characterized by repression of the PPARα signaling pathway has increased incidence of severe AKI. These findings point toward interesting associations between sepsis-associated AKI and PPARα-driven fatty acid metabolism that merit further investigation.

Interleukin-27 as a candidate diagnostic biomarker for bacterial infection in immunocompromised pediatric patients.

BACKGROUND: Immunocompromised pediatric patients constitute a growing population that is particularly vulnerable to bacterial infection, necessitating prompt recognition and treatment. This study assessed the utility of interleukin-27 (IL-27) and procalcitonin (PCT) as biomarkers of bacterial infection among immunocompromised pediatric subjects. METHODS: This is a single-center prospective cohort study conducted from July 2016 through September 2017, drawing subjects from the inpatient units at Cincinnati Children's Hospital Medical Center (CCHMC), a large, tertiary care children's hospital. Patients were included if they fit the definition of immunocompromised and were under clinical suspicion for infection, defined by the acquisition of a blood culture at any point during the admission. The primary analysis assessed the accuracy of IL-27 to diagnose bacterial infection in immunocompromised pediatric patients, using PCT as a comparator. RESULTS: 293 patients were recruited, representing 400 episodes of suspected bacterial infection. The median age was 7.8 years (IQR 3.1-13.8 years). Fifty-three percent (n = 213) of the population had a primary oncologic diagnosis, 24% (n = 95) had received a bone marrow transplant, and 21% (n = 85) had received a solid organ transplant. The overall infection rate was 37%, with 70% of those patients having some form of culture positivity. Twenty-eight-day mortality was 5%, 60-day mortality was 9%, with 87% of patients surviving to hospital discharge. The AUC's of the ROC curve to diagnose bacterial infection were 0.62 (0.5-0.68) for IL-27 and 0.65 (0.6-0.73) for PCT. Using the previously determined cutoff of 5.0 ng/mL, the specificity of IL-27 to diagnose bacterial infection reached 94%, with a negative predictive value of 64%. CONCLUSIONS: Despite prior work demonstrating IL-27 and PCT as possible biomarkers of bacterial infection in immunocompromised pediatric patients, we were unable to validate these findings. This illustrates the challenges associated with developing reliable biomarkers of bacterial infection in this vulnerable population.

A Retrospective Evaluation of Echocardiograms to Establish Normative Inferior Vena Cava and Aortic Measurements for Children Younger Than 6 Years.

OBJECTIVES: The ability to plot the inferior vena cava (IVC) size on a normal curve for pediatric patients may prove beneficial. First, in patients with normal cardiac anatomy who present in shock, assessing IVC size may be valuable for evaluating the degree of dehydration. Second, in children with heart disease, understanding how a child's IVC size compares to normal could be particularly beneficial for patients with right heart disease. We sought to create normal curves for the IVC and aorta in children younger than 6 years. METHODS: Data were gathered from 347 echocardiograms of healthy children younger than 6 years in a retrospective study at a quaternary care children's hospital. From the subcostal long- and short-axis images, maximum diameters in the transverse and longitudinal views were obtained for both the IVC and the aorta. RESULTS: Both IVC and aortic dimensions increased in a linear fashion and had excellent correlations with the body surface area, body mass, and height (IVC, r = 0.78-0.81; P < .0001; aorta, r = 0.82-0.86; P < .0001). CONCLUSIONS: In children younger than 6 years, the IVC and aorta increase linearly as the children grow. Such normal curves will be beneficial for assessing a pediatric patient's hydration status or right heart function in patients with congenital heart disease.

Hyperchloremia Is Associated With Complicated Course and Mortality in Pediatric Patients With Septic Shock.

OBJECTIVE: Hyperchloremia is associated with poor outcome among critically ill adults, but it is unknown if a similar association exists among critically ill children. We determined if hyperchloremia is associated with poor outcomes in children with septic shock. DESIGN: Retrospective analysis of a pediatric septic shock database. SETTING: Twenty-nine PICUs in the United States. PATIENTS: Eight hundred ninety children 10 years and younger with septic shock. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We considered the minimum, maximum, and mean chloride values during the initial 7 days of septic shock for each study subject as separate hyperchloremia variables. Within each category, we considered hyperchloremia as a dichotomous variable defined as a serum concentration greater than or equal to 110 mmol/L. We used multivariable logistic regression to determine the association between the hyperchloremia variables and outcome, adjusted for illness severity. We considered all cause 28-day mortality and complicated course as the primary outcome variables. Complicated course was defined as mortality by 28 days or persistence of greater than or equal to two organ failures at day 7 of septic shock. Secondarily, we conducted a stratified analysis using a biomarker-based mortality risk stratification tool. There were 226 patients (25%) with a complicated course and 93 mortalities (10%). Seventy patients had a minimum chloride greater than or equal to 110 mmol/L, 179 had a mean chloride greater than or equal to 110 mmol/L, and 514 had a maximum chloride greater than or equal to 110 mmol/L. A minimum chloride greater than or equal to 110 mmol/L was associated with increased odds of complicated course (odds ratio, 1.9; 95% CI, 1.1-3.2; p = 0.023) and mortality (odds ratio, 3.7; 95% CI, 2.0-6.8; p < 0.001). A mean chloride greater than or equal to 110 mmol/L was also associated with increased odds of mortality (odds ratio, 2.1; 95% CI, 1.3-3.5; p = 0.002). The secondary analysis yielded similar results. CONCLUSION: Hyperchloremia is independently associated with poor outcomes among children with septic shock.

Management of acute asthma exacerbations.

PURPOSE OF REVIEW: Herein, we review the current guidelines for the management of children with an acute asthma exacerbation. We focus on management in the emergency department, inpatient, and ICU settings. RECENT FINDINGS: The most recent statistics show that the prevalence of asthma during childhood has decreased in certain demographic subgroups and plateaued in other subgroups. However, acute asthma accounts for significant healthcare expenditures. Although there are few, if any, newer therapeutic agents available for management of acute asthma exacerbations, several reports leveraging quality improvement science have shown significant reductions in costs of care as well as improvements in outcome. SUMMARY: Asthma is one of the most common chronic conditions in children and the most common reason that children are admitted to the hospital. Nevertheless, the evidence to support specific agents in the management of acute asthma exacerbations is surprisingly limited. The management of acute exacerbations focuses on reversal of bronchospasm, correction of hypoxia, and prevention of relapse and recurrence. Second-tier and third-tier agents are infrequently used outside of the ICU setting. Reducing the variation in treatment is likely to lead to lower costs and better outcomes.

High resolution mapping and positional cloning of ENU-induced mutations in the Rw region of mouse chromosome 5.

BACKGROUND: Forward genetic screens in mice provide an unbiased means to identify genes and other functional genetic elements in the genome. Previously, a large scale ENU mutagenesis screen was conducted to query the functional content of a ~50 Mb region of the mouse genome on proximal Chr 5. The majority of phenotypic mutants recovered were embryonic lethals. RESULTS: We report the high resolution genetic mapping, complementation analyses, and positional cloning of mutations in the target region. The collection of identified alleles include several with known or presumed functions for which no mutant models have been reported (Tbc1d14, Nol14, Tyms, Cad, Fbxl5, Haus3), and mutations in genes we or others previously reported (Tapt1, Rest, Ugdh, Paxip1, Hmx1, Otoe, Nsun7). We also confirmed the causative nature of a homeotic mutation with a targeted allele, mapped a lethal mutation to a large gene desert, and localized a spermiogenesis mutation to a region in which no annotated genes have coding mutations. The mutation in Tbc1d14 provides the first implication of a critical developmental role for RAB-GAP-mediated protein transport in early embryogenesis. CONCLUSION: This collection of alleles contributes to the goal of assigning biological functions to all known genes, as well as identifying novel functional elements that would be missed by reverse genetic approaches.

Bioinformatic tools for studying post-transcriptional gene regulation : The UAlbany TUTR collection and other informatic resources.

The untranslated regions (UTRs) of many mRNAs contain sequence and structural motifs that are used to regulate the stability, localization, and translatability of the mRNA. It should be possible to discover previously unidentified RNA regulatory motifs by examining many related nucleotide sequences, which are assumed to contain a common motif. This is a general practice for discovery of DNA-based sequence-based patterns, in which alignment tools are heavily exploited. However, because of the complexity of sequential and structural components of RNA-based motifs, simple-alignment tools are frequently inadequate. The consensus sequences they find frequently have the potential for significant variability at any given position and are only loosely characterized. The development of RNA-motif discovery tools that infer and integrate structural information into motif discovery is both necessary and expedient. Here, we provide a selected list of existing web-accessible algorithms for the discovery of RNA motifs, which, although not exhaustive, represents the current state of the art. To facilitate the development, evaluation, and training of new software programs that identify RNA motifs, we created the UAlbany training UTR (TUTR) database, which is a collection of validated sets of sequences containing experimentally defined regulatory motifs. Presently, eleven training sets have been generated with associated indexes and "answer sets" provided that identify where the previously characterized RNA motif [the iron responsive element (IRE), AU-rich class-2 element (ARE), selenocysteine insertion sequence (SECIS), etc.] resides in each sequence. The UAlbany TUTR collection is a shared resource that is available to researchers for software development and as a research aid.