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1.
Predialytic versus Intradialytic Nutrition: A Study to Assess Effects on Intradialytic Blood Pressure, Dialysis Adequacy, and Urea Removal.
Rao, NS, Chandra, A, Saran, S, Kulshreshta, MR, Mishra, P, Tiwari, P
Blood purification. 2021;(6):823-828
Abstract
BACKGROUND Provision of oral protein in hemodialysis (HD) is desirable due to improved compliance to protein requirements and better nutritional status, but the risks of hypotension and underdialysis need to be considered. This study compared 2 different timings for administering oral nutritional supplements (ONS), predialysis and mid-dialysis, with respect to hemodynamics, dialysis adequacy, urea removal, and tolerability. METHODS This single-center, prospective crossover study analyzed 72 stable patients with ESRD on twice a week maintenance HD with a mean age of 38.7 (±11.2) years and a dialysis vintage of 28.2 (±13.1) months. In the first week, all the patients received ONS (450 kcal energy, 20 g protein) 1 h prior to start of dialysis (group 1) and in the next week, the supplement was administered after 2 h of start of dialysis (group 2), with a predialysis fasting period of at least 3 h in both groups. Blood pressures, serum, and spent dialysate samples were collected and nausea occurrence was noted by severity. RESULTS Predialytic intake (group 1) was associated with higher predialysis and 1st hour blood urea, dialysis adequacy, and urea removal than group 2. Both groups achieved mean Kt/V > 1.2, and the occurrence of symptomatic hypotensive episodes and nausea was not significantly different between the groups. On repeated measures ANOVA, changes in blood urea over time showed significant group effect. CONCLUSIONS Predialytic supplementation was associated with better dialysis adequacy and urea removal than intradialytic supplementation. However, both timings were equally tolerated and not associated with underdialysis.
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2.
Application of controlled release urea improved grain yield and nitrogen use efficiency: A meta-analysis.
Zhu, S, Liu, L, Xu, Y, Yang, Y, Shi, R
PloS one. 2020;(10):e0241481
Abstract
The application of controlled release urea (CRU) has been proposed as a crucial method to reduce the adverse environmental effects induced by conventional urea (CU). Yet, a systematic and quantitative analysis on how CRU affects staple crop production including wheat (Triticum aestivum L.), maize (Zea mays L.), and rice (Oryza sativa L.) is lacking. Here, a meta-analysis was conducted to determine how CRU influences soil chemical properties, total nitrogen (TN) uptake, grain yield, and nitrogen use efficiency (NUE) of staple crop in China. The results indicated that CRU application significantly increased soil organic carbon (SOC), TN, and available nitrogen (AN) by 5.93%, 3.89% and 13.98% respectively overall, while soil pH showed no significant changes. Compared to the application of CU, applying CRU significantly increased grain yield by 7.23%, which was mainly owing to the higher TN uptake (9.13%) across all the studies. In addition, the application of CRU significantly increased NUE, nitrogen agronomy efficiency (NAE), utilization rate of nitrogen fertilizer (NUR), and nitrogen physiological efficiency (NPE) by an average of 23.4%, 34.65%, 25.83% and 15.8% respectively which could be attributed to the slow nitrogen (N) release characteristics of CRU. The positive effect of CRU on grain yield and NUE of staple crop was greatest when the content of SOC and TN were extremely low, indicating that it was most effective to improve grain production of infertile soil by applying CRU. The finding of this study indicated that the application of CRU should be promoted for grain production, especially for infertile soil.
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3.
Monitoring training and recovery responses with heart rate measures during standardized warm-up in elite badminton players.
Schneider, C, Wiewelhove, T, McLaren, SJ, Röleke, L, Käsbauer, H, Hecksteden, A, Kellmann, M, Pfeiffer, M, Ferrauti, A
PloS one. 2020;(12):e0244412
Abstract
PURPOSE To investigate short-term training and recovery-related effects on heart rate during a standardized submaximal running test. METHODS Ten elite badminton players (7 females and 3 males) were monitored during a 12-week training period in preparation for the World Championships. Exercise heart rate (HRex) and perceived exertion were measured in response to a 5-min submaximal shuttle-run test during the morning session warm-up. This test was repeatedly performed on Mondays after 1-2 days of pronounced recovery ('recovered' state; reference condition) and on Fridays following 4 consecutive days of training ('strained' state). In addition, the serum concentration of creatine kinase and urea, perceived recovery-stress states, and jump performance were assessed before warm-up. RESULTS Creatine kinase increased in the strained compared to the recovered state and the perceived recovery-stress ratings decreased and increased, respectively (range of average effects sizes: |d| = 0.93-2.90). The overall HRex was 173 bpm and the observed within-player variability (i.e., standard deviation as a coefficient of variation [CV]) was 1.3% (90% confidence interval: 1.2% to 1.5%). A linear reduction of -1.4% (-3.0% to 0.3%) was observed in HRex over the 12-week observational period. HRex was -1.5% lower (-2.2% to -0.9%) in the strained compared to the recovered state, and the standard deviation (as a CV) representing interindividual variability in this response was 0.7% (-0.6% to 1.2%). CONCLUSIONS Our findings suggest that HRex measured during a standardized warm-up can be sensitive to short-term accumulation of training load, with HRex decreasing on average in response to consecutive days of training within repeated preparatory weekly microcycles. From a practical perspective, it seems advisable to determine intra-individual recovery-strain responses by repeated testing, as HRex responses may vary substantially between and within players.
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4.
Effect of urea cream on sorafenib-associated hand-foot skin reaction in patients with hepatocellular carcinoma: A multicenter, randomised, double-blind controlled study.
Lee, YS, Jung, YK, Kim, JH, Cho, SB, Kim, DY, Kim, MY, Kim, HJ, Seo, YS, Yoon, KT, Hong, YM, et al
European journal of cancer (Oxford, England : 1990). 2020;:19-27
Abstract
BACKGROUND Hand-foot skin reaction (HFSR) is the most common adverse event during sorafenib treatment in patients with hepatocellular carcinoma (HCC). In the present study, we aimed to investigate the role of urea cream in the prevention of HFSR or amelioration of HFSR severity. PATIENTS AND METHODS Patients with HCC were treated with either placebo cream or urea cream for 12 weeks concomitantly with sorafenib treatment. HFSR development, the Hand-Foot Skin Reaction and Quality of Life (HF-QoL) questionnaire score, and adverse events were assessed at 2, 4, 8 and 12 weeks. RESULTS Of the 288 patients, 247 patients, with 117 patients in the placebo control group and 130 patients in the urea cream group, were analysed. The urea cream group showed a trend towards a lower cumulative incidence of any-grade HFSR (log-rank, P = 0.247) and severe HFSR of grade II or higher (log-rank, P = 0.394) without statistical significance. In the incidence by time point, the incidence of severe HFSR of grade II or higher was significantly lower in the urea cream group than in the placebo control group at 2 weeks (13.8% versus 23.9%, P = 0.042). The urea cream group showed a significantly better HF-QoL questionnaire score than the placebo control group (11.8 versus 19.7, P = 0.014) at 12 weeks. CONCLUSIONS Treatment with urea cream showed a lower incidence of severe sorafenib-induced HFSR at 2 weeks and reduced the tendency of HFSR development in HCC patients. Therefore, treatment with urea cream may be considered for prophylaxis or improvement of HFSR grade in HCC patients treated with sorafenib. TRIAL REGISTRATION ClinicalTrials.gov (NCT03212625).
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5.
Urea for Chronic Hyponatremia.
Rondon-Berrios, H
Blood purification. 2020;(1-2):212-218
Abstract
BACKGROUND Hyponatremia is the most common electrolyte disorder encountered clinically. While acute and/or severe hyponatremia is commonly associated with significant symptoms, milder and more chronic forms of hyponatremia remain clinically inconspicuous. Recent evidence suggests that even milder forms of hyponatremia are associated with increased morbidity and mortality. Despite this, currently available treatments for chronic hyponatremia lack data on efficacy and/or have important limitations related to patient nonadherence, adverse side effects, and/or significant costs. Consequently, there is a clear need for investigation of alternative treatments for this common condition. SUMMARY Small case series conducted in Europe since the early 1980s suggest that urea, an oral osmotic diuretic that increases urinary water excretion, is safe and effective for the treatment of chronic hyponatremia. In 2016, a novel formulation of urea became available in the United States. Our group recently reported the first and only study describing the efficacy and safety of this American formulation of oral urea among hospitalized patients with hyponatremia. Key Messages: Oral urea appears to be an effective, safe, and well-tolerated therapeutic strategy in the management of chronic hyponatremia.
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6.
Prospective Comparison of PET Imaging with PSMA-Targeted 18F-DCFPyL Versus Na18F for Bone Lesion Detection in Patients with Metastatic Prostate Cancer.
Rowe, SP, Li, X, Trock, BJ, Werner, RA, Frey, S, DiGianvittorio, M, Bleiler, JK, Reyes, DK, Abdallah, R, Pienta, KJ, et al
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2020;(2):183-188
Abstract
Bone metastases in prostate cancer (PCa) have important prognostic significance, and imaging modalities used for PCa staging should have high sensitivity for detecting such lesions. Prostate-specific membrane antigen (PSMA)-targeted PET radiotracers are promising new agents for imaging PCa. We undertook a head-to-head comparison of PSMA-targeted 2-(3-{1-carboxy-5-[(6-18F-fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18F-DCFPyL) PET to Na18F PET to determine which modality was more sensitive for the detection of lesions suggestive of bone metastases in a group of patients with metastatic PCa. Methods: Patients with progressive, metastatic PCa were prospectively imaged with both 18F-DCFPyL and Na18F PET/CT, with both scans occurring within 24 h of each other. A consensus 2-reader central review was performed to identify all bone lesions suggestive of sites of PCa involvement on both scans, and maximized SUVs corrected for body weight (SUVmax) and lean body mass (SULmax) were recorded. Soft-tissue lesions were also noted on both scans, and SUVmax, SULmax, and PSMA reporting and data system (RADS) version 1.0 scores were recorded. Data from the 2 scans were compared using a generalized estimating equation. Results: In total, 16 patients meeting all inclusion criteria were enrolled in this study, and 15 of the 16 (93.8%) were imaged with both PET radiotracers. In total, 405 bone lesions suggestive of sites of PCa were identified on at least 1 scan. On 18F-DCFPyL PET/CT, 391 (96.5%) were definitively positive, 4 (1.0%) were equivocally positive, and 10 (2.5%) were negative. On Na18F PET/CT, the corresponding values were 388 (95.8%), 4 (1.0%), and 13 (3.2%). Of the definitively negative lesions on 18F-DCFPyL PET, 8 of 10 (80.0%) were sclerotic and 2 of 10 (20.0%) were infiltrative or marrow-based. Additionally, 12 of 13 (92.3%) of the definitively negative lesions on Na18F PET were infiltrative or marrow-based and 1 of 13 (7.7%) was lytic. Also identified were 78 PSMA-RADS-4, 17 PSMA-RADS-5, and 1 PSMA-RADS-3C soft-tissue lesions. Conclusion: PET/CT imaging using 18F-DCFPyL and Na18F PET had nearly identical sensitivities for the detection of bone lesions in patients with metastatic PCa. As would be expected, PSMA-targeted PET provides more information on soft-tissue disease. There may be little additional value to imaging PCa patients with Na18F after a PSMA-targeted PET scan has already been performed.
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7.
Bioelectrical Impedance Measurements for Assessment of Kidney Function in Critically Ill Patients.
de Jong, LAA, Otten-Helmers, AG, Spronk, PE, van Kan, HJM
Critical care medicine. 2019;(12):e984-e992
Abstract
OBJECTIVES To evaluate the use of multifrequency bioelectrical impedance analysis to predict creatinine/urea clearance based on 24 hours urine collection. A practical formula was developed, and its performance was compared with that of established formulas such as Cockcroft-Gault, Modification of Diet in Renal Disease, and Jelliffe's. DESIGN An open-label prospective observational cohort study. SETTING A 12-bed ICU at a nonuniversity major teaching hospital (Gelre ziekenhuizen Apeldoorn/Zutphen, The Netherlands). PATIENTS Adult critical care patients with an expected ICU length of stay at admission of at least 48 hours. INTERVENTIONS Each patient's body composition was assessed using a validated Quadscan 4000 analyzer (Bodystat, Isle of Man, British Isles). Twenty-four hours urine was collected, and laboratory variables in serum including creatinine, urea, and albumin were obtained at the beginning and end of the collection period. MEASUREMENTS AND MAIN RESULTS A total of 151 patients, stratified to an acute and nonacute ICU-group, were enrolled in the study over a 2-year period. A formula to predict creatinine/urea clearance based on 24 hours urine collection was developed using stepwise linear regression using a training data set of 75 patients. This formula was subsequently tested and compared with other relevant predictive equations using a validation data set of 76 patients. Serum creatinine values ranged from 40 to 446 µmol/L. With the predictive model based on estimated body cell mass and a "prediction marker" more than 71% of the observed variance in creatinine/urea clearance based on 24 hours urine collection could be explained. Predictive performance was superior to the other eight evaluated models (R = 0.39-0.55) and demonstrated to be constant over the whole range of creatinine/urea clearance based on 24 hours urine collection values. CONCLUSIONS Multifrequency bioelectrical impedance analysis measurements can be used to predict creatinine/urea clearance based on 24 hours urine collection with superior performance than currently established prediction models. This rapid, noninvasive method enables correction for influences of a patient's actual body composition and may prove valuable in daily clinical practice.
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8.
Dynamics of Bacterial and Viral Communities in Paddy Soil with Irrigation and Urea Application.
Li, Y, Sun, H, Yang, W, Chen, G, Xu, H
Viruses. 2019;(4)
Abstract
Viruses are ubiquitous in natural systems. By influencing bacterial abundance (BA) and community structure through lysis-lysogenic conversion, viruses are involved in various ecological processes. In agricultural management, nitrogen addition and irrigation should be considered as important factors that can modify soil viral dynamics but have been ignored. In our study, short-term dynamics of autochthonous soil viral and bacterial abundance and diversity after irrigation and urea application were examined in a long-term experimental paddy field. Urea addition delayed the emergence of peak viral abundance for three days, suggesting that viruses are sensitive to N addition. Under short-term eutrophic conditions through urea application, viruses undertake a lysogenic-biased strategy. Moreover, nitrogen-fixing bacteria were most likely specifically lysed in urea-treated soil, which suggests that soil viruses block N accumulation by killing nitrogen-fixing bacteria. To the best of our knowledge, this study is the first to investigate dynamic changes in autochthonous viruses in paddy fields.
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9.
Urea reduction ratio may be a simpler approach for measurement of adequacy of intermittent hemodialysis in acute kidney injury.
Liang, KV, Zhang, JH, Palevsky, PM
BMC nephrology. 2019;(1):82
Abstract
BACKGROUND Assessment of adequacy of intermittent hemodialysis (IHD) is conventionally based upon urea kinetic models for calculation of single pool Kt/Vurea (Kt/V), with 1.2 accepted as minimum adequate clearance for thrice weekly IHD. In the Acute Renal Failure Trial Network (ATN) Study, adequacy of IHD in patients with acute kidney injury (AKI) was assessed using Kt/V. However, equations for Kt/V require volume of distribution of urea, which is highly variable in AKI. Therefore, simpler methods are needed to assess adequacy of IHD in AKI. We assessed correlation of urea reduction ratio (URR) with Kt/V and determined URR thresholds corresponding to Kt/V values to determine if URR could be a simpler means to assess the delivered dose of IHD. METHODS Using patients who received IHD for 2.5-6 h and with pre-dialysis BUN ≥20 mg/dL, we plotted URR against Kt/V. We determined URR thresholds (0.60 to 0.75) corresponding to Kt/V ≥ 1.2, 1.3, and 1.4. We generated receiver operating characteristic (ROC) curves for increasing URR values for each level of Kt/V to identify the corresponding thresholds of URR. RESULTS There was strong correlation between URR and Kt/V. ROC curves comparing URR with Kt/V ≥ 1.2, 1.3, and 1.4 had area under the curves (AUC) of 0.99. Sensitivity and specificity of URR ≥0.67 for corresponding values of Kt/V ≥ 1.2 were 0.769 (95% CI: 0.745 to 0.793) and 0.999 (95% CI: 0.997 to 1.000), respectively and the sensitivity and specificity of URR ≥0.67 for corresponding values of Kt/V ≥ 1.4 were 0.998 (95% CI: 0.995 to 1.000) and 0.791 (95% CI: 0.771 to 0.811), respectively. CONCLUSIONS Targeting a URR ≥0.67 provides a simplified means of assessing adequacy of IHD in patients with AKI. Use of URR will enhance ability to assess delivery of small solute clearance and improve adherence with clinical practice guidelines in AKI.
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10.
A swan song for Kt/Vurea.
Vanholder, R, Van Biesen, W, Lameire, N
Seminars in dialysis. 2019;(5):424-437
Abstract
Dialyzer clearance of urea multiplied by dialysis time and normalized for urea distribution volume (Kt/Vurea or simply Kt/V) has been used as an index of dialysis adequacy since more than 30 years. This article reviews the flaws of Kt/V, starting with a lack of proof of concept in three randomized controlled hard outcome trials (RCTs), and continuing with a long list of conditions where the concept of Kt/V was shown to be flawed. This information leaves little room for any conclusion other than that Kt/V, as an indicator of dialysis adequacy, is obsolete. The dialysis patient might benefit more if, instead, the nephrology community concentrates in the future on pursuing the optimal dialysis dose that conforms with adequate quality of life and on factors that are likely to affect outcomes more than Kt/V. These include residual renal function, volume status, dialysis length, ultrafiltration rate, the number of intra-dialytic hypotensive episodes, interdialytic blood pressure, serum potassium and phosphate, serum albumin, and C reactive protein.