Monitoring Of Urea Research Articles

Blood urea monitoring in heart failure patients - an important predictor of mortality

Abstract Background Recent ESC position statement regarding worsening renal failure recommends the use of blood urea monitoring of patients with heart failure with reduced ejection fraction (HFrEF). Although both serum creatinine and blood urea nitrogen are markers for renal dysfunction, blood urea nitrogen levels are also affected by reabsorption in the renal tubules, a process modulated by renin-angiotensin-aldosterone activity, sympathetic nervous activity and arginine-vasopressin activity. Thus, neurohormonal activity is reflected in the BUN/creatinine ratio (bUCR) which effectively ‘normalizes’ BUN for the degree of renal dysfunction, as measured by the creatinine level. Previous studies have demonstrated increased mortality at bUCR >100mmol/l. however, most of the prognostic data has come from patients admitted with acute heart failure. The use of bUCR in patients with chronic HFrHF receiving intensive titration of guideline directed medical therapy (GDMT) has not been studied. Purpose To identify the extent of blood urea monitoring in primary care in HFrEF and whether bUCR remains a significant prognostic indicator despite intensive GDMT. Methods We analysed the electronic health records of all patients referred to the Heart Failure Nurse Service (HFNS) in an NHS population approx. 400,000 in 2022. Inclusion criteria consists of patients with symptomatic heart failure NYHA II-IV with echocardiogram demonstrating HFrEF. Patients were segregated into two cohorts, with a urea/creatinine ratio greater or less than 100mmol/l and analysed. Results Data from 338 patients [mean age 72.3 ± 15.6 years; 218 (64.5%) males; 143 (42.3%) ischaemic cardiomyopathy; 141 (41.7%) AF; 49 (14.5%)] were analysed. Of these, 112 (33.1%) had chronic kidney disease (CKD) with eGFR <60 ml/min/1.73m2 at the time of HF diagnosis and 181 (53.6%) had CKD on discharge from the HFNS. During follow-up, 132 (39%) had further admission with HF and 76 (22.5%) died. Sixty-eight (20.1%) patients did not have blood urea checked despite the availability of serum creatinine. While an eGFR < 60 ml/min/1.73m2 at discharge was associated with a twofold increased risk of death (OR 2.4, 95% CI 1.1-5.3, p=0.029), a bUCR > 100mmol/l at discharge was associated with a four-times greater risk of death (OR 4.2, 95% CI 2.2-7.9, p <0.001). Conclusion Blood urea/creatinine ratio is an important predictor of outcome and can be utilised to help identify at-risk patients with HFrEF despite intensive GDMT.Survival from diagnosis bUCR

Development of an osmosis-assisted hollow microneedle array integrated with dual-functional electrochemical sensor for urea and pH monitoring in interstitial fluid

In healthcare, accurate detection of biomarkers is paramount for disease diagnosis, prevention, and personal health surveillance. This study focused on developing and validating a MgCl2 deposited hollow microneedle array integrated with a dual-functional sensor system, which was used for osmosis-assisted boosted interstitial fluid extraction, the simultaneous and continuous monitoring of urea and pH in interstitial fluid. The urea sensor component was fabricated by electro-depositing prussian blue onto a carbon electrode, followed by applying a molecularly imprinted polymer layer, ensuring high specificity and sensitivity. The pH sensor was constructed through electropolymerization of polyaniline, exhibiting a linear response across a wide pH range. When tested in artificial skin matrix, the system demonstrated excellent in vitro electrochemical sensing performance with high linearity and repeatability. At the same time, the practical in vivo sensing performance of the system was verified in Sprague-Dawley (SD) rats. The development of the system underscores its potential as a valuable tool for continuous health monitoring.

Relationship between Plasma and Saliva Urea Nitrogen Concentrations in New Zealand Red Deer Calves (Cervus elaphus).

Red deer (Cervus elaphus), like other ruminants, excrete approximately 70% of the nitrogen they ingest. Developing ways in which to reduce the rate of loss, such as manipulating the diet or selecting for efficiency of growth, requires close monitoring of the plasma urea N (PUN) concentration which, in turn, requires a simple, safe, and reliable method for collecting samples. Saliva is easier to collect than blood, but the relationship between the salivary urea N (SUN) and the PUN is not known for red deer. This was therefore evaluated in two strains of mixed-sex red deer calves (Cervus elaphus): a phenotype with a high seasonality of growth (H, n = 10) and a phenotype with a low seasonality of growth (L, n = 13). Both phenotypes were divided into two groups, which were each offered one of two forage-based diets ad libitum: a medium-quality diverse treatment and a low-quality perennial ryegrass-white clover treatment. Blood and saliva samples for the determination of the PUN and SUN were collected at dawn every four weeks for five months (April to September 2022). There was a strong linear relationship between the PUN and SUN in the pooled sample (R2 = 0.65, p < 0.001). The estimations of the PUN were significantly improved by adding diet and the date of sampling into the model (p < 0.001), but not phenotype (p > 0.75). SUN represents a reliable index of the PUN, and collecting saliva therefore represents a simple and inexpensive alternative to collecting blood samples in studies of nitrogen metabolism in red deer.

Nanoengineered Nonenzymatic Paper-Based Fluorescent Platform for Pre-Dilution-Free and Visual Real-Time Home Monitoring of Urea for Early Warning of Abnormal Nitrogen-Based Unhealthy Issues.

Distorted urea levels indicate several liver, kidney, or metabolic diseases; however, traditional clinical urea detection relies on urease-based methods enslaved to well-known limitations of high-price, unstable properties, complicated sample pretreatment and analysis procedures, and difficult visual real-time monitoring. Herein, nonenzymatic paper-based fluorescent materials (UFP-BP) are strategically integrated with an on-demand fluorescent-sensor (UFP) self-aggregated nanoparticle on commercial filter paper for pre-dilution-free and visual real-time urea monitoring. The UFP is synthesized and self-aggregated into the fluorescent nanoparticles for selective urea recognition. Then, the nanoparticles are interstitially loaded on filter paper to nanoengineer the UFP-BP, achieving selective quantitative urea detection in the normal concentration range (10-1000mm). UFP and UFP-BP can successfully monitor urea levels in real rat urine, artificial simulants, and milk. The proposed sensing platform, integrated with smartphones, offers accurate, quantitative, nonenzymatic, noninvasive, pre-dilution-free, on-site, rapid, low-cost, easy-to-operate, real-time visual urea detection in food samples and human body fluids. The designed sensing system can provide early warnings of abnormal nitrogen-based health issues.

A novel urease-assisted ratiometric fluorescence sensing platform based on pH-modulated copper-quenched near-infrared carbon dots and methyl red-quenched red carbon dots for selective urea monitoring.

A novel and sensitive fluorescence ratiometric method is developed for urea detection based on the pH-sensitive response of two fluorescent carbon dot (CD) systems: R-CDs/methyl red (MR) and NIR-CDs/Cu2+. The sensing mechanism involves breaking down urea using the enzyme urease, releasing ammonia and increasing pH. At higher pH, the fluorescence of NIR-CDs is quenched due to the enhanced interaction with Cu2+, while the fluorescence of R-CDs is restored as the acidic MR converts to its basic form, removing the inner filter effect. The ratiometric signal (F608/F750) of the R-CDs/MR and NIR-CDs/Cu2+ intensities changed in response to the pH induced by urea hydrolysis, enabling selective and sensitive urea detection. Detailed spectroscopic and morphological investigations confirmed the fluorescence probe design and elucidated the sensing mechanism. The method exhibited excellent sensitivity (0.00028 mMLOD) and linearity range (0.001 - 8.0 mM) for urea detection, with successful application in milk samples for monitoring adulteration, demonstrating negligible interference and high recovery levels (96.5% to 101.0%). This ratiometric fluorescence approach offers a robust strategy for selective urea sensing in complicated matrices.

Touch–based potentiometric sensors for simultaneous detection of urea and ammonium from fingertip sweat

Urea is a biomarker for diagnosis and management of multiple disorders. The measurement of urea could help in the diagnosis of patients with kidney dysfunction. Despite their attractive analytical performances, the existing urea measurement methods are still limited to sophisticated and time–consuming or require invasive blood sampling. Herein, a reliable noninvasive, simple, and disposable touch–based potentiometric sensor is fabricated for rapid monitoring of fingertip sweat urea. Novel touch–based urea detection relies on immobilized urease recognition and a solid–contact ammonium–ion–selective electrode, along with a screen–printed carbon working electrode modified carboxylated carbon nanotubes for enhancing sensor’s sensitivity. The fingertip sweat under sedentary rest conditions can be instantaneously collected on customized porous polyvinyl alcohol hydrogel transporting sweat to working electrode surface where the hydrolysis of urea is catalyzed, generating bicarbonate and ammonium. The resulting ammonium can be detected with ion–selective transducer, enabling indirect monitoring of sweat urea. Potential interference from co–existing ammonium in human sweat is addressed by developing a dual disposable potentiometric sensor, consisting of urea and ammonium sensors on a single strip platform allowing for simultaneous touch–based detection of sweat urea and ammonium. The resulting dual disposable sensing system offers rapid urea and ammonium monitoring within a group of healthy human subjects, along with a good correlation with R2 = 0.974 between the sweat urea and capillary blood urea levels. Additional confirmation among a broad sample of individuals along with the validation of sensor data through centralized laboratory tests will establish the practicality of simultaneously monitoring urea and ammonium levels.

Nickel-cobalt metal-organic frameworks based flexible hydrogel as a wearable contact lens for electrochemical sensing of urea in tear samples.

Aflexible, wearable, non-invasivecontact lens sensor utilizing nickel-cobalt metal-organic framework (Ni-Co-MOF) based hydrogel is introducedfor urea monitoring in tear samples. The synthesized Ni-Co-MOF hydrogel exhibits a porous structure with interconnected voids, as visualized by Scanning Electron Microscopy (SEM). Detailed structural and vibrational properties of the material were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR)spectroscopy, and Raman spectroscopy. The developed Ni-Co-MOF hydrogel sensor showcases a detection limit of 0.445 mM for urea within a linear range of 0.5-70 mM. Notably, it demonstrates exceptional selectivity, effectively distinguishing against interfering species like UA, AA, glucose, dopamine, Cl-, K+, Na+, Ca2+, and IgG. The enhanced electrocatalytic performance of the Ni-Co-MOF hydrogel electrode is attributed to the presence of Ni and Co, fostering Ni2+ oxidation on the surface and forming a Co2+ complex that acts as a catalyst for urea oxidation. The fabricated sensor exhibits successful detection and retrieval of urea in simulated tear samples, showcasing promising potential for bioanalytical applications. The binder-free, non-toxic nature of the Ni-Co-MOF hydrogel sensor presents exciting avenues for future utilization in non-enzymatic electrochemical sensing, including applications in wearable devices, point-of-care diagnostics, and personalized healthcare monitoring.

The correlation of urea and creatinine concentrations in sweat and saliva with plasma during hemodialysis: an observational cohort study.

Urea and creatinine concentrations in plasma are used to guide hemodialysis (HD) in patients with end-stage renal disease (ESRD). To support individualized HD treatment in a home situation, there is a clinical need for a non-invasive and continuous alternative to plasma for biomarker monitoring during and between cycles of HD. In this observational study, we therefore established the correlation of urea and creatinine concentrations between sweat, saliva and plasma in a cohort of ESRD patients on HD. Forty HD patients were recruited at the Dialysis Department of the Catharina Hospital Eindhoven. Sweat and salivary urea and creatinine concentrations were analyzed at the start and at the end of one HD cycle and compared to the corresponding plasma concentrations. A decrease of urea concentrations during HD was observed in sweat, from 27.86 mmol/L to 12.60 mmol/L, and saliva, from 24.70 mmol/L to 5.64 mmol/L. Urea concentrations in sweat and saliva strongly correlated with the concentrations in plasma (ρ 0.92 [p<0.001] and 0.94 [p<0.001], respectively). Creatinine concentrations also decreased in sweat from 43.39 μmol/L to 19.69 μmol/L, and saliva, from 59.00 μmol/L to 13.70 μmol/L. However, for creatinine, correlation coefficients were lower than for urea for both sweat and saliva compared to plasma (ρ: 0.58 [p<0.001] and 0.77 [p<0.001], respectively). The results illustrate a proof of principle of urea measurements in sweat and saliva to monitor HD adequacy in a non-invasive and continuous manner. Biosensors enabling urea monitoring in sweat or saliva could fill in a clinical need to enable at-home HD for more patients and thereby decrease patient burden.

Wearable Microneedle Patch for Transdermal Electrochemical Monitoring of Urea in Interstitial Fluid.

Microneedle-based wearable electrochemical biosensors are the new frontier in personalized health monitoring and disease diagnostic devices that provide an alternative tool to traditional blood-based invasive techniques. Advancements in micro- and nanofabrication technologies enabled the fabrication of microneedles using different biomaterials and morphological features with the aim of overcoming existing challenges and enhancing sensing performance. In this work, we report a microneedle array featuring conductive recessed microcavities for monitoring urea levels in the interstitial fluid of the skin. Microcavities are small pockets on the tip of each microneedle that can accommodate the sensing layer, provide protection from delamination during skin insertion or removal, and position the sensing layer in a deep layer of the skin to reach the interstitial fluid. The wearable urea patch has shown to be highly sensitive and selective in monitoring urea, with a sensitivity of 2.5 mV mM-1 and a linear range of 3 to 18 mM making it suitable for monitoring urea levels in healthy individuals and patients. Our ex vivo experiments have shown that recessed microcavities can protect the sensing layer from delamination during skin insertion and monitor changing urea levels in interstitial fluid. This biocompatible platform provides alternative solutions to the critical issue of maintaining the performance of the biosensor upon skin insertion and holds great potential for advancing transdermal sensor technology.

High-Throughput Automatic Laser Printing Strategy toward Cost-effective Portable Integrated Urea Tele-Monitoring System.

A portable sweat urea sensing system is a promising solution to satisfy the booming requirement of kidney function tele-monitoring. However, the complicated manufacturing route and the cumbersome electrochemical testing system still need to be improved to develop the urea point-of-care testing (POCT) and tele-monitoring devices. Here, a universal technical route based on a high-throughput automatic laser printing strategy for fabricating the portable integrated urea monitoring system is proposed. This integrated system includes a high-performance laser-printed urea sensing electrode, a planar three-electrode system, and a self-developed wireless mini-electrochemical workstation. A precursor donor layer is activated by laser scribing and in situ transferred into functional nanoparticles for the drop-on-demand printing of the urea sensing electrode. The obtained electrodes show high sensitivity, low detection limit, fast response time, high selectivity, good average recovery, and long-term stability for urea sensing. Additionally, a laser-induced graphene circuit-based miniature planar three-electrode system and a wireless mini-electrochemical workstation are designed for sensing data collection and transmitting, achieving real-time urea POCT and tele-monitoring. This scalable method provides a universal solution for high-throughput and ultra-fast fabrication of urea-sensing electrodes. The portable integrated urea monitoring system is a competitive option to achieve cost-effective POCT and tele-monitoring for kidney function.

Exploiting the Advantages of Ag/ITO/Enzyme Trapped Gel Layers to Develop a Highly Sensitive and Selective Fiber Optic Plasmonic Urea Sensor

The fabrication and characterization of a surface plasmon resonance (SPR)-based urea biosensor, with thin silver (Ag), ITO (In2O3: SnO2), and enzyme-trapped gel over an unclad portion of plastic-clad silica fiber as a sensing element, is represented. The working principle is to identify changes in the refractive index of the enzyme (urease) entrapped gel layer following the interaction with the incoming analyte. This interaction causes swelling and shrinkage of the gel layer, which alters the effective refractive index of the sensing layer. The wavelength interrogation method is used, and the optimized sensor probe is characterized by urea samples having different pH values. Scanning electron microscopy confirmed the uniformity of the silver layer over the unclad core of the fiber. The sensor operates from 0 to 160 mM of urea concentrations to cover the physiological concentration range of blood urea normally present in the human body. The sensitivity and limit of detection (LOD) offered by the sensor are marked 0.59387 nm/mM near zero concentration of the urea sample and 0.56 mM, respectively, along with the provisions of high stability, remote sensing, and online monitoring of urea. The proposed sensor has proven to be one of a kind due to its fast response time.

Fluorometric and Colorimetric Hybrid Carbon-Dot Nanosensors for Dual Monitoring of Urea

Fluorometric and Colorimetric Hybrid Carbon-Dot Nanosensors for Dual Monitoring of Urea

Highly accurate multimodal monitoring of lactate and urea in sweat by soft epidermal optofluidics with single-band Raman scattering

The shifting paradigm in clinical practice to remote healthcare underscores the need to develop novel biosensing modalities to rapidly and continuously assess digital and metabolic biomarkers. Sweat is a rich, heterogeneous biofluid that provides broad insights from the underlying dynamic metabolic activity of human physiology and enables new unobtrusive ways to monitor health status continuously. However, eccrine sweat is a relatively unexplored body fluid and has scant use in clinical practices. Here, we introduce a novel, easy-to-fabricate skin-interfaced sweat collection epidermal microfluidics, which enables multimodal analysis coupled with spontaneous Raman scattering. The introduced wearable optofluidic patch is soft, fully flexible, can robustly interface with the skin without inducing chemical or physical irritation, and has minimal optical interfaces to the spectra of the analytes. The proposed detection approach by Raman scattering provides label-free chemical fingerprint information, enabling quantitative optical biosensing with high sensitivity and selectivity. As a great advantage, the proposed epidermal optofluidics and optical biosensing technique require neither plasmonic surface fabrication for surface Raman enhancement nor bulky ultrashort-pulsed lasers for coherent Raman enhancement, which are typically acquired for increasing Raman signal intensity and sensitivity of quantitative Raman analysis. Moreover, the developed system enables simultaneous sweat glucose, lactate, and urea concentration monitoring. Furthermore, we show that biomolecule concentration monitoring with only one Raman shift simplifies spectroscopies instrumentation complexities and eliminates the requirement of advanced data processing methods to analyze the entire Raman spectra. Therefore, the proposed “single-band Raman analysis” coupled with developed epidermal optofluidics (epioptofluidics) shows accurate, repeatable, and stable sweat biomolecule analysis and proposes instrument down-scale and miniaturization possibilities.

Comparison of Serum Urea, Salivary Urea, and Creatinine Levels in Pre-Dialysis and Post-Dialysis Patients: A Case-Control Study.

Background Frequent venepuncturefor monitoring of serum urea and creatinine in chronic kidney disease (CKD) patients on dialysis will result in venous damage and infection. In this research, we assessed the feasibility of utilizing salivary samples as a substitute for serum samples in determining the levels of urea and creatinine in patients with CKD undergoing dialysis. Methods The study participants included 50 patients diagnosed with CKD undergoing hemodialysis and an equal number of apparently healthy individuals. We measured the serum and salivary levels of urea and creatinine in normal subjects.CKD patients were also subjected to similar investigations both before and after hemodialysis. Results In our study, we found that the mean value of salivary urea and creatinine are significantly elevated in the case group (salivary urea: 99.56 ± 43.28 mg/dL, salivary creatinine: 1.10 ± 0.83 mg/dL) as compared to the control group (salivary urea: 33.62 ± 23.84 mg/dL, salivary creatinine: 0.15±0.12 mg/dL, p value: <0.001). There was a statistically significant reduction in the mean value of salivary urea and creatinine in the post-dialysis sample (salivary urea: 45.06 ± 30.37 mg/dL, salivary creatinine: 0.43±0.44 mg/dL) compared to the pre-dialysis sample (salivary urea: 99.56 ± 43.28 mg/dL, salivary creatinine: 1.10 ± 0.83 mg/dL; p value: <0.001)in the case group. The salivary urea is significantly positively correlated with serum urea (r value: 0.366, p value: 0.009). But there is nosignificant correlation seen between salivary and serum creatinine. We have created a cut-off for salivary urea (52.5 mg/dL) to diagnose CKD which has a good sensitivity (84%) and specificity (78%). Conclusion The results of our study suggest that the estimation of salivary urea and creatinine could serve as a non-invasive, alternative marker for the diagnosis of CKD, and benefit in risk-free monitoring of their progress before and after hemodialysis.

Multiplex Chroma Response Wearable Hydrogel Patch: Visual Monitoring of Urea in Body Fluids for Health Prognosis.

Visual wearable devices can rapid intuitively monitor biomarkers in body fluids to indicate the human health status and provide valuable reference for further medical diagnosis. However, unavoidable interference factors such as skin color, natural light, and background luminescence can interfere with the visualization accuracy of flexible wearable devices, limiting their practical sensing application. Here, we designed a wearable sensing patch via an embedded upconversion optical probe in a 3D porous polyacrylamide hydrogel, exhibiting a multiplex chroma response to urea based on the inner filter effect, which overcomes the susceptibility to external conditions due to its near-infrared excited luminescence and improves the resolution and accuracy of visual sensing. Furthermore, a highly compatible portable sensing platform combined with a smartphone was designed to achieve in situ rapid quantitative analysis of urea. The limit of detection values of the upconversion optical probe and hydrogel sensor are as low as 1.4 and 30 μM respectively, exhibiting the practicality in different scenarios. The designed sensing patch provides a convenient and accurate sensing strategy for the detection of biomarkers in body fluids and has the potential to be developed into a point-of-care device to provide disease early warning and clinical diagnosis.

Wearable potentiometric biosensor for analysis of urea in sweat

Herein, we introduce wearable potentiometric biosensors on screen-printed carbon electrodes (SPCEs) for on-body and on-site monitoring of urea in sweat. The biosensor architecture was judiciously designed to detect urea at different pHs and incorporate a pH sensor, thus containing polyaniline ink, urease bioink and a polyvinylchloride membrane. Urea detection could be performed in the wide range from 5 to 200 mM at pH 7.0, encompassing urea levels in human sweat. The biosensor response was fast (incubation time 5 min), with no interference from other substances in sweat. Reliable urea detection could be done in undiluted human sweat with a skin-worn flexible device using the pH correction strategy afforded by the pH sensor. The performance of the epidermal biosensor was not affected by severe bending strains. The feasibility of mass production was demonstrated by fabricating epidermal flexible biosensors using slot-die coating with a roll-to-roll technique.

Clinical and Inflammatory Profile of COVID-19 Infection at a Tertiary Care Centre in Northern Part of Tamil Nadu - A Retrospective Study.

Introduction The coronavirus disease (COVID-19) pandemic has incurred high costs for the entire planet. The complex interactions between the host, virus, and environment have resulted in various clinical outcomes. It is crucial to comprehend sickness severity and outcome predictors to provide early preventative measures for a better outcome. The current study aimed to determine the association of clinical and inflammatory profiles with the outcome of COVID-19 infection in patients admitted to the intensive care unit. Methods This retrospective study was done in patients admitted to intensive care units for COVID-19 with a positive reverse transcriptase polymerase chain reaction (RTPCR) assay. A total of 125 patients above 18 years were included in the study. The patient's age, gender, and co-morbidities like type 2 diabetes mellitus, hypertension, respiratory illness, and coronary artery disease were noted. The patient's symptomatology, vital signs, oxygen saturation (Spo2), need for inotropes, and non-invasive positive pressure ventilator support (NIPPV) were observed. Computed tomography severity score (CTSS) and hematological and inflammatory parameters at the time of admission were noticed. Patient's management and treatment outcomes as survivors and non-survivors were noted. Results The mean age was significantly greater in non-survivors. The common symptoms were fever, respiratory distress, cough, muscle pain, and sore throat. The leucocyte count, C-reactive protein (CRP), urea, creatinine, interleukin-6 (IL-6), and lactate dehydrogenase (LDH) were greater, and platelet counts were lower significantly in the non-survivors group. On multivariable logistic regression, CT severity score, NIPPV, and IL-6 had an odds ratio of 1.17, 0.052, and 1.03, respectively. IL-6 had a sensitivity of 81.5% and a specificity of 81.8% with a cut-off value of 37.5. Conclusion Vigilant monitoring of leucocyte count, CRP, urea, creatinine, IL-6, LDH, platelet count, and CT severity score is essential for managing COVID-19 infection. IL-6 was found to be a significant marker as a predictor of outcome in our study.

AN ENZYMATIC METHOD FOR THE DETERMINATION OF UREA IN AQUEOUS SAMPLES USING CRUDE UREASE FROM Citrullus lanatus SEEDS

This paper presents an enzyme-based method for the determination of urea in aqueous samples using crude urease from Citrullus lanatus seeds. The method is based on the enzymatic hydrolysis of Urea into ammonia (NH4) and carbon dioxide (CO2) by urease. Ammonia formation is determined spectrophotometrically after nesslerization and then quantitatively related to urea concentration via a calibration curve. Reaction conditions for the assay were investigated and optimized. Optimum temperature was found to be 50 oC, optimum pH was 8.0 and optimum reaction time was 10 minutes. The Calibration curve for urea determination was linear (R2 =0.987) within the concentration range of 0.5 – 50 mg/L. Limits of detection and quantification (LOD and LOQ) for the method were 0.08 and 0.13 mg/L respectively. Application of the method to urea determination in surface water samples revealed good precision (1.45 – 3.28 % RSD) and accuracy (84 – 92% recovery). The presented method is simple and has the potential to be a practical tool for monitoring of urea in environmental samples.

NiO–MoO3 nanocomposite: A sensitive non-enzymatic sensor for glucose and urea monitoring

Binary transition metal nanocomposites have attracted much attention in the bio-sensing field due to their high activity. In this work, nickel oxide-molybdenum trioxide (NiO–MoO3) nanocomposite as a non-enzymatic sensor for glucose and urea oxidation is synthesized by a simple hydrothermal method. The nanocomposite synthesis is demonstrated using XRD, Raman, SEM, and TEM techniques. The electrochemical activity of the developed sensor is determined by cyclic voltammetry, differential pulse voltammetry, impedance spectroscopic, and chronoamperometry. The detection limit of NiO–MoO3 nanocomposite is found to be 0.86 and 0.85 μM for urea and glucose, respectively. From the chronoamperometry test, this sensor maintains 66% and 65% of the initial current for urea and glucose, respectively, representing excellent stability. The results indicate that the NiO–MoO3 nanocomposite has an excellent potential for the detection of glucose and urea.

Impact on grafted kidney function of rocuronium-sugammadex vs cisatracurium-neostigmine strategy for neuromuscular block management. An Italian single-center, 2014-2017 retrospective cohort case-control study

BackgroundThe impact of sugammadex in patients with end-stage renal disease undergoing kidney transplantation is still far from being defined. The aim of the study is to compare sugammadex to neostigmine for reversal of rocuronium- and cisatracurium-induced neuromuscular block (NMB), respectively, in patients undergoing kidney transplantation.MethodsA single-center, 2014-2017 retrospective cohort case-control study was performed. A total of 350 patients undergoing kidney transplantation, equally divided between a sugammadex group (175 patients) and a neostigmine group (175 patients), were considered. Postoperative kidney function, evaluated by monitoring of serum creatinine and urea and estimated glomerular filtration rate (eGFR), was the endpoint. Other endpoints were anesthetic and surgical times, post-anesthesia care unit length of stay, postoperative intensive care unit admission, and recurrent NMB or complications.ResultsNo significant differences in patient or, with the exception of drugs involved in NMB management, anesthetic, and surgical characteristics, were observed between the two groups. Serum creatinine (median [interquartile range]: 596.0 [478.0-749.0] vs 639.0 [527.7-870.0] μmol/L, p = 0.0128) and serum urea (14.9 [10.8-21.6] vs 17.1 [13.1-22.0] mmol/L, p = 0.0486) were lower, while eGFR (8.0 [6.0-11.0] vs 8.0 [6.0-10.0], p = 0.0473) was higher in the sugammadex group than in the neostigmine group after surgery. The sugammadex group showed significantly lower incidence of postoperative severe hypoxemia (0.6% vs 6.3%, p = 0.006), shorter PACU stay (70 [60-90] min vs 90 [60-105] min, p < 0.001), and reduced ICU admissions (0.6% vs 8.0%, p = 0.001).ConclusionsCompared to cisatracurium-neostigmine, the rocuronium-sugammadex strategy for reversal of NMB showed a better recovery profile in patients undergoing kidney transplantation.