Search Results (7)

Autism spectrum disorder (ASD) has been associated with disruptions in tryptophan (TRP) metabolism, affecting the production of key neuroactive metabolites. Investigating these metabolic pathways could yield valuable biomarkers for ASD severity and progression. We included 44 children with ASD and 44 healthy children, members of the same family. The average age in the ASD group was 10.7 years, while the average age in the control group was 9.4 years. Urinary tryptophan metabolites were quantified via liquid chromatography—mass spectrometry operating multiple reaction monitoring (MRM). Urinary creatinine was analyzed on an Advia 2400 analyzer using the Jaffe reaction. Statistical comparisons were made between ASD subgroups based on CARS scores. Our findings indicate that children with ASD have higher TRP concentrations (19.94 vs. 16.91; p = 0.04) than their siblings. Kynurenine (KYN) was found at higher levels in children with ASD compared to children in the control group (82.34 vs. 71.20; p = 0.86), although this difference was not statistically significant. The ASD group showed trends of higher KYN/TRP ratios and altered TRP/ indole-3-acetic acid (IAA) and TRP/5-hydroxyindoleacetic acid (5-HIAA) ratios, correlating with symptom severity. Although the numbers of the two groups were different, our findings suggest that mild and severe illnesses involve separate mechanisms. However, further comprehensive studies are needed to validate these ratios as diagnostic tools for ASD. Full article

Chronic kidney disease (CKD) is a progressive condition that affects more than 10% of the world’s population. Monitoring urine albumin-to-creatinine ratio (uACR) has become the gold standard for nephropathy diagnosis and control. The objective of the present study was to develop a simple, accurate, sensitive, and rapid point-of-care test (PoCT) device, MyACR, for uACR measurement, intended for use in community healthcare to screen for the risk and monitor the progress of CKD. Albumin and creatinine concentrations in urine samples were determined using spectrophotometric dye (tetrabromophenol blue)-binding and colorimetric Jaffe assay, respectively. Urine samples were diluted with distilled water (1:80) and mixed separately with albumin and creatinine reaction mixture. The creatinine reaction was incubated at room temperature (25 °C) for 30 min before analysis. Optical density (OD) was measured at the wavelengths of 625 nm (albumin) and 515 nm (creatinine). All calibration curves (0–60 mg/L and 0–2 mg/dL for albumin and creatinine) yielded linear relationships with correlation coefficients (R²) of >0.997. Good accuracy (% deviation of mean value (DMV) ≤ 5.42%) and precision (% coefficients of variation (CV) ≤ 12.69%) were observed from both the intra- and inter-day assays for the determination of albumin and creatinine using MyACR. The limit of quantification (LOQ) of albumin and creatinine in urine samples determined using MyACR and a laboratory spectrophotometer were 5 mg/L and 0.25 mg/dL, respectively, using 37.5 μL urine spiked samples (n = 5). The device was well-applied with clinical samples from 20 CKD patients. The median (range) of %DMV of the central (hospital) laboratory method (immune-based assay) was 3.48 (−17.05 to 21.64)%, with a high correlation coefficient (R² > 0.98). In conclusion, MyACR showed satisfactory test performance in terms of accuracy, reproducibility, and sensitivity. Cost-effectiveness and improvement in clinical decision making need to be proven in future multisite community and home studies. Full article

In this work, a new microfluidic paper-based analytical device (µPAD) was developed for on-hand creatinine quantification in urine samples. When compared to conventional methods, this innovative paper device is more accessible and portable, it provides low-cost analysis (cost of consumables of 40 cents), and it is applicable to non-invasive biological fluids. Furthermore, the paper-based approach is used within an environmentally friendly assembly with no need for wax printing and small amounts of reagents resulting in low waste production and easy disposal by incineration. Its assembly method includes cutting paper discs arranged into several reading units within a plastic pouch, enabling effective creatinine quantification with accuracy based on a vertical flow approach. The method is based on the colourimetric reaction between creatinine and alkaline picric acid, where the solution colour changes from yellow to orange/red. Under optimal conditions, the developed method allowed creatinine quantification in the dynamic range of 2.20–35.0 mg/dL, with a limit of detection (LOD) of 0.66 mg/dL and a limit of quantification (LOQ) of 2.20 mg/dL. The colour intensity developed was processed in ImageJ software, based on digital image scanning, performed in 20 min (up to 4 h) after the sample insertion. The device is stable for up to one week when stored in a vacuum at 4 °C. The method was validated by comparing the results with a batch-wise procedure, where there were no statistically significant differences between both methods. Full article

Given the significance of uric acid and creatinine in clinical diagnostic, disease prevention and treatment, a multifunctional electrochemical sensor was proposed for sensitive detection of uric acid and creatinine. The sensitive detection of uric acid was realized based on the unique electrochemical oxidation of nanoporous gold (NPG) towards uric acid, showing good linearity from 10 μM to 750 μM with a satisfactory sensitivity of 222.91 μA mM⁻¹ cm⁻² and a limit of detection (LOD) of 0.06 μM. Based on the Jaffé reaction between creatinine and picric acid, the sensitive detection of creatinine was indirectly achieved in a range from 10 to 2000 μM by determining the consumption of picric acid in the Jaffé reaction with a detection sensitivity of 195.05 μA mM⁻¹ cm⁻² and a LOD of 10 μM. For human urine detection using the proposed electrochemical sensor, the uric acid detection results were comparable to that of high-performance liquid chromatography (HPLC), with a deviation rate of less than 10.28% and the recoveries of uric acid spiked in urine samples were 89~118%. Compared with HPLC results, the deviation rate of creatinine detection in urine samples was less than 4.17% and the recoveries of creatinine spiked in urine samples ranged from 92.50% to 117.40%. The multifunctional electrochemical sensor exhibited many advantages in practical applications, including short detection time, high stability, simple operation, strong anti-interference ability, cost-effectiveness, and easy fabrication, which provided a promising alternative for urine analysis in clinical diagnosis. Full article

A simple, rapid, and accurate HPLC-UV method was developed for the determination of creatinine in pig urine. Usually, it is determined in urine in biomonitoring of xenobiotics to correct for variations in dilutions of urine samples. The colorimetric method (based on Jaffe reaction), which was mainly used for this purpose in mycotoxin biomonitoring, is not a reliable approach for pig urine. Therefore, a novel and accurate HPLC method for creatinine determination was developed. The sample preparation was based on the dilute and shoot approach. An HPLC separation was performed with a porous graphitic carbon column with an aqueous mobile phase to achieve satisfactory retention time for creatinine. The method has been successfully validated, applied for the determination of creatinine in pig urine, and compared with other methods commonly used for that purpose—a colorimetric method based on Jaffe reaction and commercial ELISA test. The developed HPLC method shows the highest precision and accuracy for pig urine samples. Finally, the method was applied as a normalization tool in LC-MS/MS mycotoxin biomarkers analysis. The standardization to a constant creatinine level (0.5 mg/mL) enables similar matrix effects for eleven mycotoxin biomarkers for pig urine samples with different creatinine levels. Full article

This work presents a new dual-purpose detector for photometric and conductivity measurements in flow-based analysis. The photometric detector is a paired emitter–detector diode (PEDD) device, whilst the conductivity detection employs a capacitively coupled contactless conductivity detector (C4D). The flow-through detection cell is a rectangular acrylic block (ca. 2 × 2 × 1.5 cm) with cylindrical channels in Z-configuration. For the PEDD detector, the LED light source and detector are installed inside the acrylic block. The two electrodes of the C4D are silver conducting ink painted on the PEEK inlet and outlet tubing of the Z-flow cell. The dual-purpose detector is coupled with a sequential injection analysis (SIA) system for simultaneous detection of the absorbance of the orange dye and conductivity of the dissolved oral rehydration salt powder. The detector was also used for sequential measurements of creatinine and the conductivity of human urine samples. The creatinine analysis is based on colorimetric detection of the Jaffé reaction using the PEDD detector, and the conductivity of the urine, as measured by the C4D detector, is expressed in millisiemens (mS cm⁻¹). Full article

An integrated system consisting of a paper-based chip and a smart detection device is proposed for determining the human serum creatinine concentration based on Jaffé reaction theory. In the proposed approach, the reaction zone of the paper-based chip is implanted with picric acid and NaOH reagent and dried at 35 °C for 20 min. Human serum creatinine is dripped onto the reaction zone of the chip. A Jaffé reaction is induced by heating the chip at 37 °C for 5 min and the creatinine concentration is then derived by analyzing the RGB (red, green and blue) intensity of the resulting Janovsky complex using self-written analysis software installed on a smartphone. The validity of the proposed method is demonstrated using control samples with creatinine concentrations ranging from 0.2~8 mg/dL. The detection results obtained for 32 real-world creatinine samples are shown to be in excellent agreement with those obtained using a standard macroscale method (R² = 0.9994). Overall, the results show that the proposed system provides a compact, low-cost and reliable approach for human serum creatinine concentration detection. Full article