Optical Real-Time Cardiorenal Toxin Uric Acid Measurement During Hemodialysis Using a Miniaturized Optical Sensor.

Patients with chronic kidney disease (CKD) are at higher cardiovascular risk than the general population. Cardiovascular diseases, vascular calcification among them, are the leading cause of death in these patients. Factors influencing vascular calcification are oxidative stress, inflammation, and accumulation of uremic toxins during CKD.

Time-averaged concentration estimation of uraemic toxins with different removal kinetics: a novel approach based on intradialytic spent dialysate measurements.

Background: Kt/V is the most used marker to estimate dialysis adequacy; however, it does not reflect the removal of many other uraemic toxins, and a new approach is needed. We have assessed the feasibility of estimating intradialytic serum time-averaged concentration (TAC) of various uraemic toxins from their spent dialysate concentrations that can be estimated non-invasively online with optical methods.

Methods: Serum and spent dialysate levels and total removed solute (TRS) of urea, uric acid (UA), indoxyl sulphate (IS) and β2-microglobulin (β2M) were evaluated with laboratory methods during 312 haemodialysis sessions in 78 patients with four different dialysis treatment settings.

Treatment with Paracetamol Can Interfere with the Intradialytic Optical Estimation in Spent Dialysate of Uric Acid but Not of Indoxyl Sulfate.

Optical online methods are used to monitor the haemodialysis treatment efficiency of end stage kidney disease (ESKD) patients. The aim of this study was to analyse the effect of the administration of UV-absorbing drugs, such as paracetamol (Par), on the accuracy of optical monitoring the removal of uremic toxins uric acid (UA) and indoxyl sulfate (IS) during standard haemodialysis (HD) and haemodiafiltration (HDF) treatments. Nine patients received Par in daily dosages 1−4 g for 30 sessions.

A Novel Physical Fatigue Assessment Method Utilizing Heart Rate Variability and Pulse Arrival Time towards Personalized Feedback with Wearable Sensors.

This paper proposes a novel method for physical fatigue assessment that can be applied in wearable systems, by utilizing a set of real-time measurable cardiovascular parameters. Daylength measurements, including a morning test set, physical exercise during the day, and an afternoon test set were conducted on 16 healthy subjects (8 female and 8 male). To analyze cardiovascular parameters for physical fatigue assessment, electrocardiography, pulse wave and blood pressure were measured during the test sets.

Optical Method and Biochemical Source for the Assessment of the Middle-Molecule Uremic Toxin β2-Microglobulin in Spent Dialysate.

Optical monitoring of spent dialysate has been used to estimate the removal of water-soluble low molecular weight as well as protein-bound uremic toxins from the blood of end stage kidney disease (ESKD) patients. The aim of this work was to develop an optical method to estimate the removal of β2-microglobulin (β2M), a marker of middle molecule (MM) uremic toxins, during hemodialysis (HD) treatment. Ultraviolet (UV) and fluorescence spectra of dialysate samples were recorded from 88 dialysis sessions of 22 ESKD patients, receiving four different settings of dialysis treatments.

Data Sharing Under the General Data Protection Regulation: Time to Harmonize Law and Research Ethics?

The General Data Protection Regulation (GDPR) became binding law in the European Union Member States in 2018, as a step toward harmonizing personal data protection legislation in the European Union. The Regulation governs almost all types of personal data processing, hence, also, those pertaining to biomedical research. The purpose of this article is to highlight the main practical issues related to data and biological sample sharing that biomedical researchers face regularly, and to specify how these are addressed in the context of GDPR, after consulting with ethics/legal experts.

Serum Levels and Removal by Haemodialysis and Haemodiafiltration of Tryptophan-Derived Uremic Toxins in ESKD Patients.

Tryptophan is an essential dietary amino acid that originates uremic toxins that contribute to end-stage kidney disease (ESKD) patient outcomes. We evaluated serum levels and removal during haemodialysis and haemodiafiltration of tryptophan and tryptophan-derived uremic toxins, indoxyl sulfate (IS) and indole acetic acid (IAA), in ESKD patients in different dialysis treatment settings. This prospective multicentre study in four European dialysis centres enrolled 78 patients with ESKD.

Removal of Urea, β2-Microglobulin, and Indoxyl Sulfate Assessed by Absorbance and Fluorescence in the Spent Dialysate During Hemodialysis.

In this study, simultaneous removal assessment of marker molecules from three uremic toxin groups was performed during different hemodialysis treatment modalities using optical characteristics of spent dialysate. Results from optical measurements were compared with the results from chemical laboratory. Ten chronic dialysis patients, mean age 59 ± 15 years, were included in the study during 40 hemodialysis sessions.

Free Pentosidine Assessment Based on Fluorescence Measurements in Spent Dialysate.

The aim of this study was to primarily explore the relationship between free pentosidine and the fluorescence properties of spent dialysate, and also to develop a model to assess the levels of free pentosidine in spent dialysate based on the fluorescence measurements. First, 40 patients (20 females and 20 males) were examined during 40 dialysis sessions. High-pressure liquid chromatography (HPLC) was used to measure the free pentosidine concentrations from the spent dialysate.

4-Pyridoxic Acid in the Spent Dialysate: Contribution to Fluorescence and Optical Monitoring.

Aim: In this work we estimated the contribution of the fluorescence of 4-pyridoxic acid (4-PA) to the total fluorescence of spent dialysate with the aim of evaluating the on-line monitoring of removal of this vitamin B-6 metabolite from the blood of patients with end-stage renal disease (ESRD).

Methods: Spectrofluorometric analysis of spent dialysate, collected from hemodialysis and hemodiafiltration sessions of 10 patients receiving regularly pyridoxine injections after dialysis treatment, was performed in the range of Ex/Em 220-500 nm. 4-PA in dialysate samples was identified and quantified using HPLC with fluorescent and MS/MS detection.

Is Fluorescence Valid to Monitor Removal of Protein Bound Uremic Solutes in Dialysis?

The aim of this study was to evaluate the contribution and removal dynamics of the main fluorophores during dialysis by analyzing the spent dialysate samples to prove the hypothesis whether the fluorescence of spent dialysate can be utilized for monitoring removal of any of the protein bound uremic solute. A high performance liquid chromatography system was used to separate and quantify fluorophoric solutes in the spent dialysate sampled at the start and the end of 99 dialysis sessions, including 57 hemodialysis and 42 hemodiafiltration treatments. Fluorescence was acquired at excitation 280 nm and emission 360 nm.

Optical Estimation of Beta 2 Microglobulin during Hemodiafiltration – Does It Work?

Background: Currently, urea reduction seems to be the most widely used dialysis dose parameter. The aim of this study was to investigate the possibility to monitor beta 2-microglobulin (β2-M) elimination by utilizing the ultraviolet (UV) absorbance of spent dialysate.

Methods: Blood and spent dialysate were collected during two week's sessions in 8 patients, one week in hemodialysis (HD) and one in hemodiafiltration (HDF).

Lean body mass assessment based on UV absorbance in spent dialysate and dual-energy x-ray absorptiometry.

Purpose: The aim of the study was to explore the possibility of assessing lean body mass (LBM) based on UV absorbance measurements in spent dialysate.

Methods: 9 patients on chronic three-times-a-week HD (4 female, 5 male, mean age 58.8 ± 8.

An optical method for serum calcium and phosphorus level assessment during hemodialysis.

Survival among hemodialysis patients is disturbingly low, partly because vascular calcification (VC) and cardiovascular disease are highly prevalent. Elevated serum phosphorus (P) and calcium (Ca) levels play an essential role in the formation of VC events. The purpose of the current study was to reveal optical monitoring possibilities of serum P and Ca values during dialysis.

Urea Rebound Assessment Based on UV Absorbance in Spent Dialysate.

The aim of the study was to examine the possibility of postdialysis urea rebound assessment using UV-absorbance measurements in spent dialysate. Twenty-six patients on chronic three-times-a-week hemodialysis (HD) were studied in two separate studies. Double-beam spectrophotometer was used for the determination of UV absorbance in the collected spent dialysate samples.

Estimation of removed uremic toxin indoxyl sulphate during hemodialysis by using optical data of the spent dialysate.

The aim of this study was to explore the possibility to determine the amount of total removed Indoxyl Sulphate (TR_IS) during dialysis session, an optical method utilizing absorbance and fluorescence spectral data of the spent dialysate was used. Eight uremic patients from Linköping, Sweden and 10 from Tallinn, Estonia, were studied during dialysis treatments. Dialysate samples were taken during each treatment and analyzed at a laboratory.

Paracetamol interference in uric Acid levels in uremic patients revealed by monitoring spent dialysate.

The aim of this study was to assess removal dynamics of paracetamol (PAR), as an extraordinary chromophore in spent dialysate, upon the optical monitoring of dialysis of end-stage renal disease patients with inflammation complications. Seven dialysis sessions of different patients were followed to whom PAR was used as a pain reliever or antipyretic. Spent dialysate was sampled hourly and analyzed using HPLC with MS/MS and UV detection.

Accurate dialysis dose evaluation and extrapolation algorithms during online optical dialysis monitoring.

The aim of this study was to propose an improved method for accurate dialysis dose evaluation and extrapolation by means of Kt/ V from online UV-absorbance measurements for real time and continuous treatment monitoring. The study included a total of 24 treatments from ten uremic patients, seven of whom were male and three females. All patients were on chronic thrice-weekly hemodialysis therapy.

Do only small uremic toxins, chromophores, contribute to the online dialysis dose monitoring by UV absorbance?

The aim of this work was to evaluate the contributions of the main chromophores to the total UV absorbance of the spent dialysate and to assess removal dynamics of these solutes during optical on-line dialysis dose monitoring. High performance chromatography was used to separate and quantify UV-absorbing solutes in the spent dialysate sampled at the start and at the end of dialysis sessions. Chromatograms were monitored at 210, 254 and 280 nm routinely and full absorption spectra were registered between 200 and 400 nm.

Optical measurement of creatinine in spent dialysate.

Aim: The aim of the study was to develop an optical method for the estimation of creatinine (Cr) removal during dialysis using UV-absorbance.

Material And Methods: 29 hemodialysis patients on chronic 3-times-a-week hemodialysis were studied in 6 separate studies. Double-beam pectrophotometer was used for the determination of UV-absorbance in the collected spent dialysate samples.

Utilization of UV absorbance for estimation of phosphate elimination during hemodiafiltration.

Background: Phosphate is an important factor in explaining the high progress of vascular calcification among dialysis patients. Today, phosphate concentration is measured in plasma on a regular basis. The aim of this study was to find out if it is possible to estimate total removed phosphate (TRp) in spent dialysate utilizing UV absorbance during hemodiafiltration.

Optical method for cardiovascular risk marker uric acid removal assessment during dialysis.

The aim of this study was to estimate the concentration of uric acid (UA) optically by using the original and processed ultraviolet (UV) absorbance spectra of spent dialysate. Also, the effect of using several wavelengths (multi-wavelength algorithms) for estimation was examined. This paper gives an overview of seven studies carried out in Linköping, Sweden, and Tallinn, Estonia.

Concentration of uric acid removed during dialysis. Estimated by multi wavelength and processed ultra violet absorbance spectra.

The aim of this study was to estimate the concentration of uric acid (UA) optically by using original and processed ultra violet (UV) absorbance spectra's of the spent dialysate. Also the effect of using several wavelengths for estimation was examined.

HPLC study of uremic fluids related to optical dialysis adequacy monitoring.

Purpose: The aim of this study was to investigate uremia-related high-performance liquid chromatography (HPLC) ultraviolet (UV) absorbance profiles of serum and spent dialysate and to study the removal of uremic retention solutes in connection with optical dialysis adequacy monitoring.

Methods: 10 uremic patients were investigated using online spectrophotometry at a wavelength of 280 nm over the course of 30 hemodialysis treatments. The dialysate and blood samples were taken and analyzed simultaneously using standard biochemical methods and reversed-phase HPLC.

A multicentre study of an enhanced optical method for measuring concentration of uric acid removed during dialysis.

The aim of this study was to compare concentration measurements of uric acid (UA) removed during dialysis by two algorithms based on UV-absorbance and the 1st derivate of UV absorbance. Ten uremic patients from Tallinn and ten from Linköping, during 30+40 haemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linköping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a double-beam spectrophotometer.