Evaluation and comparison of Abbott Jaffe and enzymatic creatinine methods: Could the old method meet the new requirements?

Profiling of antioxidant properties and identification of potential analgesic inhibitory activities of Allophylus villosus and Mycetia sinensis employing in vivo, in vitro, and computational techniques

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional use of plants for medicinal purposes, called phytomedicine, has been known to provide relief from pain. In Bangladesh, the Chakma indigenous community has been using Allophylus villosus and Mycetia sinensis to treat various types of pain and inflammation.

AIM OF THE STUDY

The object of this research is to evaluate the effectiveness of these plants in relieving pain and their antioxidant properties using various approaches such as in vitro, in vivo, and computational techniques. Additionally, the investigation will also analyse the phytochemicals present in these plants.

MATERIALS AND METHODS

We conducted in vivo analgesic experiment on Swiss albino mice and in-silico inhibitory activities on COX-2 & 15-LOX-2 enzymes. Assessment of DPPH, Anti Radical Activities (ARA), FRAP, H2O2 Free Radical Scavenging, Reducing the power of both plants performed significant % inhibition with tolerable IC50. Qualitative screening of functional groups of phytochemicals was précised by FTIR and GC-MS analysis demonstrated phytochemical investigations.

RESULTS

The ethyl acetate (EtOAc) fractioned Mycetia sinensis extract as well as the ethanoic extract and all fractioned extracts of Allophylus villosus have reported a significant percentage (%) of writhing inhibition (p < 0.05) with the concentrated doses 250 mg as well as 500 mg among the Swiss albino mice for writhing observation of analgesic effect. In the silico observation, a molecular-docking investigation has performed according to GC-MS generated 43 phyto-compounds of both plants to screen their binding affinity by targeting COX-2 and 15-LOX-2 enzymes. Consequently, in order to assess and ascertain the effectiveness of the sorted phytocompounds, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) investigation, DFT (Density-functional theory) by QM (Quantum mechanics), and MDS (Molecular dynamics simulation) were carried out. As the outcome, compounds like 5-(2,4-ditert-butylphenoxy)-5-oxopentanoic acid; 2,4-ditert-butylphenyl 5-hydroxypentanoate; 3,3-diphenyl-5-methyl-3H-pyrazole; 2-O-(6-methylheptan-2-yl) 1-O-octyl benzene-1,2-dicarboxylate and dioctan-3-yl benzene-1,2-dicarboxylate derived from the ethnic plant A. villosus and another ethnic plant M. sinensis extracts enchants magnificent analgesic inhibitions and performed more significant drug like activities with the targeted enzymes.

CONCLUSIONS

Phytocompounds from A. villosus & M. sinensis exhibited potential antagonist activity against human 15-lipoxygenase-2 and cyclooxygenase-2 proteins. The effective ester compounds from these plants performed more potential anti-nociceptive activity which could be used as a drug in future.

Development and validation of a predictive model for in-hospital mortality from perioperative bacteremia in gastrointestinal surgery

PURPOSE

Prognostic scores require fluctuating values, such as respiratory rate, which are unsuitable for retrospective auditing. Therefore, this study aimed to develop and validate a predictive model for in-hospital mortality associated with gastrointestinal surgery for retrospective auditing.

METHODS

Data from patients with bacteremia related to gastrointestinal surgery performed at Shizuoka General Hospital between July 2006 and December 2021 were extracted from a prospectively maintained database. Patients suspected of having a positive blood culture with contaminating bacteria or missing laboratory data were excluded. The remaining patients were randomly assigned in a 2:1 ratio to the deviation and validation cohorts. A logistic regression model estimated the odds ratios (ORs) and created a predictive model for in-hospital mortality. The model was evaluated using receiver operating characteristic (ROC) curves and calibration plots.

RESULTS

Of 20,637 gastrointestinal surgeries, 398 resulted in bacteremia. The median age of patients with bacteremia was 72 years, and 66.1% were male. The most common pathogens were Staphylococcus (13.9%), followed by Bacteroides (12.4%) and Escherichia (11.4%). Multivariable logistic regression showed that creatinine abnormality (P < 0.001, OR = 3.39), decreased prognostic nutritional index (P < 0.001, OR = 0.90/unit), and age ≥ 75 years (P = 0.026, OR = 2.89) were independent prognostic factors for in-hospital mortality. The area under the ROC curve of the predictive model was 0.711 in the validation cohort. The calibration plot revealed that the model slightly overestimated mortality in the validation cohort.

CONCLUSIONS

Using age, creatinine level, albumin level, and lymphocyte count, the model accurately predicted in-hospital mortality after bacteremia infection related to gastrointestinal surgery, demonstrating its suitability for retrospective audits.

Vancomycin Dosing and Its Association With Acute Kidney Injury in Pediatric Cardiac Intensive Care Patients Under 3 Months of Age

BACKGROUND

The standard vancomycin regimen for term neonates is 45 mg/kg/day. However, the optimal starting vancomycin dosing for achieving therapeutic levels in young infants in cardiac intensive care units remains unknown. Moreover, data on the association of supratherapeutic vancomycin levels with acute kidney injury (AKI) are limited.

METHODS

Retrospective study of infants ≤3 months old, receiving vancomycin following congenital heart surgery at postoperative intensive care unit admission. Assessed were vancomycin dosing, achievement of therapeutic trough concentration of 10-20 mg/L and development of AKI, based on the modified Kidney Disease Improving Global Outcomes criteria.

RESULTS

Inclusion criteria were met by 109 patients with a median age of 8 days (IQR: 6-16). The mean (SD) vancomycin dose required for achieving therapeutic concentration was 28.9 (9.1) mg/kg at the first postoperative day. Multivariate logistic regression identified higher preoperative creatinine levels and shorter cardiopulmonary bypass time as predictors of supratherapeutic vancomycin concentrations (c-index 0.788). During the treatment course, 62 (56.9%) developed AKI. Length of stay and mortality were higher in those who developed AKI as compared with those who did not. Multivariate logistic regression identified higher vancomycin concentration as a predictor for postoperative AKI, OR, 3.391 (95% CI: 1.257-9.151), P = 0.016 (c-index 0.896).

CONCLUSION

Our results support a lower starting vancomycin dose of ~30 mg/kg/day followed by an early personalized therapeutic approach, to achieve therapeutic trough concentrations of 10-20 mg/L in cardiac postoperative term infants. Supratherapeutic concentrations are associated with an increased risk for AKI, which is prevalent in this population and associated with adverse outcomes.

Improved solution-based SERS detection of creatinine by inducing hydrogen-bonding interaction for effective analyte capture

Recently, solution-based surface-enhanced Raman scattering (SERS) detection technique has been widely recognized due to its cost-effectiveness, simplicity, and ease of use. However, solution-based SERS is limited for practical applications mainly because of the weak adsorption affinity of the target biomolecules to the surface of plasmonic nanoparticles. Herein, we developed a highly sensitive solution-based SERS sensing platform based on mercaptopropionic acid (MPA)-capped silver-coated gold nanostars (SGNS@MPA), which allows efficient enrichment on the nanostars surface for improved detection of an analyte: creatinine, a potential biomarker of chronic kidney disease (CKD). The SGNS@MPA exhibited high enrichment ability towards creatinine molecules in alkaline medium (pH-9) through multiple hydrogen bonding interaction, which causes aggregation of the nanoparticles and enhances the SERS signal of creatinine. The detection limit for creatinine was achieved at 0.1 nM, with a limit of detection (LOD) value of 14.6 pM. As a proof-of-concept demonstration, we conducted the first quantitative detection of creatinine in noninvasive human fluids, such as saliva and sweat, under separation-free conditions. We achieved a detection limit of up to 1 nM for both saliva and sweat, with LOD values as low as 0.136 nM for saliva and 0.266 nM for sweat. Overall, our molecular enrichment strategy offers a new way to improve the solution-based SERS detection technique for real-world practical applications in point-of-care settings and low-resource settings.

Which is the best glomerular filtration marker: Creatinine, cystatin C or both?

BACKGROUND

The glomerular filtration rate (GFR) is estimated by the serum or plasma concentration of creatinine and/or cystatin C using equations that include demographic data. The equations worldwide most widely used are those of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) consortium and updated in 2021 to remove the Afro-American racial correction factor. In 2021 and then in 2023, the European Kidney Function Consortium also developed equations based on creatinine and cystatin C, usable across the full age spectrum, and constructed by including the Q value (i.e. the median creatinine or cystatin C in healthy men and women, which is customizable for specific populations).

METHODS

The aim of this narrative review is to examine the strengths and weaknesses of each biomarker.

RESULTS

Both biomarkers have non-GFR determinants, namely muscle mass, protein intake and tubular secretion for creatinine; dysthyroidism and systemic corticosteroids for cystatin C, as well as other more debated determinants (diabetes, obesity, proteinuria, inflammatory syndrome). These non-GFR determinants are the reason why no equation based on a single endogenous biomarker has an accuracy within 30% greater than 90% over the entire age spectrum (in at least one patient in 10, estimated GFR is at least 30% higher or at least 30% lower than the measured GFR).

CONCLUSION

Equations combining the two biomarkers provide a better estimate of GFR, particularly in the subgroup of patients whose estimates based on each of the biomarkers are highly discordant. These patients must also be identified as being at increased risk of morbidity, particularly cardiovascular, and mortality.

Colorimetric detection of serum creatinine on a miniaturized platform using hue-saturation-value space analysis

Chronic kidney disease (CKD) is a widespread condition with considerable health and economic impacts globally. However, existing methodologies for serum creatinine assessment often involve prolonged wait times and sophisticated equipment, such as spectrometers, hindering real-time diagnosis and care. Innovative solutions like point-of-care (POC) devices are emerging to address these challenges. In this context, there is a recognized need for remote, regular, automated, and low-cost analysis of serum creatinine levels, given its role as a critical parameter for CKD diagnosis and management. This study introduces a miniaturized system with integrated heater elements designed for precise serum creatinine measurement. The system operates based on the Jaffe method and accurate serum creatinine measurement within a microreservoir chip. Smartphone-based image processing using the hue-saturation-value (HSV) color space was applied to captured images of microreservoirs. The creatinine analyses were conducted in serum with a limit of detection of ~ 0.4 mg/dL and limit of quantification of ~ 1.3 mg/dL. Smartphone-based image processing employing the HSV color space outperformed spectrometric analysis for creatinine measurement conducted in serum. This pioneering technology and smartphone-based processing offer the potential for decentralized renal function testing, which could significantly contribute to improved patient care. The miniaturized system offers a low-cost alternative ($87 per device), potentially reducing healthcare expenditures (~ $0.5 per test) associated with CKD diagnosis and management. This innovation could greatly improve access to diagnosis and monitoring of CKD, especially in regions where access to sophisticated laboratory equipment is limited.

MyACR: A Point-of-Care Medical Device for Determination of Albumin-Creatinine Ratio (uACR) in Random Urine Samples as a Marker of Nephropathy

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.

Multiomic profiling of new-onset kidney function decline: insights from the STANISLAS study cohort with a 20-year follow-up

Background

Identifying the biomarkers associated with new-onset glomerular filtration rate (GFR) decrease in an initially healthy population could offer a better understanding of kidney function decline and help improving patient management.

Methods

Here we described the proteomic and transcriptomic footprints associated with new-onset kidney function decline in an initially healthy and well-characterized population with a 20-year follow-up. This study was based on 1087 individuals from the familial longitudinal Suivi Temporaire Annuel Non-Invasif de la Santé des Lorrains Assurés Sociaux (STANISLAS) cohort who attended both visit 1 (from 1993 to 1995) and visit 4 (from 2011 to 2016). New-onset kidney function decline was approached both in quantitative (GFR slope for each individual) and qualitative (defined as a decrease in GFR of >15 ml/min/1.7 m2) ways. We analysed associations of 445 proteins measured both at visit 1 and visit 4 using Olink Proseek® panels and 119 765 genes expressions measured at visit 4 with GFR decline. Associations were assessed using multivariable models. The Bonferroni correction was applied.

Results

We found several proteins (including PLC, placental growth factor (PGF), members of the tumour necrosis factor receptor superfamily), genes (including CCL18, SESN3), and a newly discovered miRNA-mRNA pair (MIR1205-DNAJC6) to be independently associated with new-onset kidney function decline. Complex network analysis highlighted both extracellular matrix and cardiovascular remodelling (since visit 1) as well as inflammation (at visit 4) as key features of early GFR decrease.

Conclusions

These findings lay the foundation to further assess whether the proteins and genes herein identified may represent potential biomarkers or therapeutic targets to prevent renal function impairment.

β,γ-Methylene-ATP and its metabolite medronic acid affect both arterial media calcification and bone mineralization in non-CKD and CKD rats

Arterial media calcification or pathological deposition of calcium-phosphate crystals in the vessel wall contributes significantly to the high mortality rate observed in patients with CKD. Extracellular nucleotides (ie, ATP or UTP) regulate the arterial calcification process by interacting with (1) purinergic receptors and (2) breakdown via ecto-nucleotidases, such as ectonucleotide pyrophosphatase/phosphodiesterase NPP1 or NPP3, affecting the local levels of calcification inhibitor, pyrophosphate, and stimulator inorganic phosphate (PPi/Pi ratio). Also, it has been shown that ATP analogs (ie, β,γ-methylene-ATP [β,γ-meATP]) inhibit vascular smooth muscle cell calcification in vitro. In the first experiment, daily dosing of β,γ-meATP (2 mg/kg) was investigated in rats fed a warfarin diet to trigger the development of non-CKD-related arterial medial calcifications. This study showed that β,γ-meATP significantly lowered the calcium scores in the aorta and peripheral vessels in warfarin-exposed rats. In a second experiment, daily dosing of 4 mg/kg β,γ-meATP and its metabolite medronic acid (MDP) was analyzed in rats fed an adenine diet to promote the development of CKD-related arterial medial calcification. Administration of β,γ-meATP and MDP did not significantly decrease aortic calcification scores in this model. Moreover, both compounds induced deleterious effects on physiological bone mineralization, causing an imminent risk for worsening the already compromised bone status in CKD. Due to this, it was not possible to raise the dosage of both compounds to tackle CKD-related arterial calcification. Again, this points out the difficult task of targeting solely ectopic calcifications without negatively affecting physiological bone mineralization. On the other hand, aortic mRNA expression of Enpp1 and Enpp3 was significantly and positively associated with aortic calcification scores, suggesting that normalizing the aortic NPP1/3 activity to control values might be a possible target to treat (CKD-induced) arterial media calcifications.

High-Sensitivity Creatinine Detection via a Dual-Emission Ratiometric Fluorescence Probe Incorporating Amino-MIL-53@Mo/ZIF-8 and Rhodamine B

Quantifying creatinine (Cn) in biological fluids is crucial for clinically assessing renal insufficiency, thyroid irregularities, and muscle damage. Therefore, it is crucial for human health to have a simple, quick, and accurate Cn analysis technique. In this study, we have successfully synthesized a 3D ratiometric dual-metal-organic framework, namely, the amino-MIL-53@Mo/ZIF-8 and rhodamie B heterostructure, using an internal strategy for sustained growth. The dual-MOF functions as an adsorbent and preconcentrates Cn. The pH, reaction time, and volume ratio of amino-MIL-53@Mo/ZIF-8/rhodamie B were optimized using the one-variable-at-a-time technique in this study. The quantitative study of the Cn concentration for this RF biosensor was obtained under ideal conditions (R2 = 0.9962, n = 3), encompassing the linear range of 0.35-11.1 μM. The detection and quantitation limits were 0.18 and 0.54 nM, respectively. Both intra- and interday reproducibility showed high repeatability of the RF biosensor, UV-vis, and ZETA potential studies, and the Stern-Volmer relationship was used to clarify the fluorescence quenching process. These superior sensing capabilities and the benefits of simple manufacturing, acceptable stability, and practicality make the RF biosensor intriguing for ultrasensitive Cn detection in practical applications.

Carbon dot-copper nanocomposite-based fluorescent sensor for detection of creatinine in urine samples of CKD patients

Creatinine (CR) is accepted as a clinical biomarker of chronic kidney disease (CKD) such as renal injury and kidney failure. To help facilitate the prognosis of CKD, a highly luminescent carbon dot (CD)-based fluorescent (FL) sensor has been built and employed for CR detection in diverse media (e.g., artificial and human urine). CDs, synthesized from sucrose precursor by a rapid microwave-assisted method (average diameter 20 nm), exhibited highly luminescent green emission upon UV exposure (λexcitation = 390 nm, λemission = 453 nm) with excellent temporal stability over three months. The nanocomposites are formed between CDs and metal ions (e.g., Cu2+) to realize the optimum biosensing of CR. Although Cu2+ ions showcases a maximum quenching (73 %) of the CDs, Cu2+/CDs system restores 77 % of the original FL intensity upon the addition of CR. The linear detection range and limit of detection for CR are estimated as 10-5 to 0.1 mg·dL-1 (R2 = 0.936) and 5.1 × 10-16 mg·dL-1, respectively. Furthermore, our biosensor shows excellent reproducibility and selectivity for CR in urine samples of healthy subjects and CKD patients. The Bland-Altman analysis for urine samples (n = 30) showcased an excellent agreement (R2 = 0.95) between our method and the gold standard 'Jaffe' method. These observations supported the practical utility of our method proposed for detection of CR in clinical samples.

The protective effect and molecular mechanism of glycyrrhizic acid glycosides against Tripterygium glycosides induced nephrotoxicity based on the RhoA/ROCK1 signalling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium glycosides (TG), which are extracted from the traditional Chinese medicine, Tripterygium wilfordii Hook F. (TwHF), has promising applications in the treatment of renal diseases; however, since its active components exerts bidirectional kidney toxicity, its clinical application is severely restricted.

AIM OF THE STUDY

Recent investigations have demonstrated definite toxicity-reducing effects from glycyrrhizic acid glycosides (GA) when combined with TG; however, the mechanism remains unclear. To our knowledge, this is the first study to investigate the specific molecular mechanism by which GA alleviates TG-induced renal toxicity from the perspective of tight junctions.

MATERIALS AND METHODS

Dynamic analyses, which investigated the changes in kidney toxicity biomarkers for different combinations and concentrations of TG and GA, were conducted for three weeks on SD rats and renal tissue structural changes were examined after three weeks of administration. Additionally, the transcription and translation levels of the relevant tight junctions and RhoA/ROCK1/MLC signalling proteins were analysed in HK-2 cells.

RESULTS

Our study showed that TG can cause transient tubulotoxicity at certain doses, and that the combined application of GA and TG can repair tight junction structures by regulating the key factors in the RhoA/ROCK1/MLC signalling pathway, thus reducing TG-induced nephrotoxicity.

CONCLUSIONS

Overall, this study provides a new strategy to reduce TG-induced toxicity by protecting renal tight junctions.

Smartphone-based low-cost and rapid quantitative detection of urinary creatinine with the Tyndall effect

This research aims to develop a robust and quantitative method for measuring creatinine levels by harnessing the enhanced Tyndall effect (TE) phenomenon. The envisioned sensing assay is designed for practical deployment in resource-limited settings or homes, where access to advanced laboratory facilities is limited. Its primary objective is to enable regular and convenient monitoring of renal healthcare, particularly in cases involving elevated creatinine levels. The creatinine sensing strategy is achieved based on the aggregation of gold nanoparticles (AuNPs) triggered via the direct crosslinking reaction between creatinine and AuNPs, where an inexpensive laser pointer was used as a handheld light source and a smartphone as a portable device to record the TE phenomenon enhanced by the creatinine-induced aggregation of AuNPs. After evaluation and optimization of parameters such as AuNP concentrations and TE measurement time, the subsequent proof-of-concept experiments demonstrated that the average gray value change of TE images was linearly related to the logarithm of creatinine concentrations in the range of 1-50 μM, with a limit of detection of 0.084 μM. Meanwhile, our proposed creatinine sensing platform exhibited highly selective detection in complex matrix environments. Our approach offers a straightforward, cost-effective, and portable means of creatinine detection, presenting an encouraging signal readout mechanism suitable for point-of-care (POC) applications. The utilization of this assay as a POC solution exhibits potential for expediting timely interventions and enhancing healthcare outcomes among individuals with renal health issues.

Comparison of Pakistani CKD-EPI, new Asian-modified CKD-EPI and revised Lund-Malmö study equations in a South Asian CKD population: a study from a Pakistani CKD cohort

BACKGROUND

Newly proposed estimating glomerular filtration rate equations need to be studied, evaluated and compared for chronic kidney disease staging, diagnosis and medication dosing in South Asians. The objectives of the study were (1) to assess the performance of the CKD-EPIPK, CKD-EPIAsian-Modified, and LMRevised equations in the Pakistani chronic kidney disease population, and (2) to investigate prospective implications on chronic kidney disease classification and end-stage kidney disease prevalence.

METHODS

We conducted a cross-sectional analysis on a chronic kidney disease cohort of 385 participants 18 years of age or above.

RESULTS

CKD-EPIPK showed the lowest bias (- 1.33 ml/min/1.73 m2), highest precision [IQR, 2.33 (- 2.36, - 0.03)] and enhanced P30 accuracy (89.35%) compared to the CKD-EPIAsian-Modified and LMRevised equations. The mean difference (ml/min/1.73 m2), 95% limit of agreement (ml/min/1.73 m2) of the equations were; CKD-EPIAsian-Modified: - 5.98, - 13.03, LMRevised: - 4.06, - 8.13 and CKD-EPIPK: - 1.18, - 6.14 (P < 0.001). CKD-EPIAsian-Modified and LMRevised showed upward re-classification of the GFR categories compared to the CKD-EPIPK equation except in the G5 category where the highest count (217, 56.36%) was noted for the CKD-EPIPK equation. End-stage kidney disease prevailed in all age groups according to all equations, and the prevalence was high in females in all equations.

CONCLUSION

CKD-EPIPK showed the best performance, whereas both CKD-EPIAsian-Modified and LMRevised showed poor performance and did not offer a sufficient advantage in chronic kidney disease classification and end-stage kidney disease prevalence estimation over CKD-EPIPK. Hence, CKD-EPIPK seems ideal for South Asians, thus appropriate measures should be taken for its implementation, at least in Pakistani laboratories.

Identification of antidiabetic inhibitors from Allophylus villosus and Mycetia sinensis by targeting α-glucosidase and PPAR-γ: In-vitro, in-vivo, and computational evidence

Diabetes mellitus (DM) is a metabolic disorder arising from insulin deficiency and defectiveness of the insulin receptor functioning on transcription factor where the body loses control to regulate glucose metabolism in β-cells, pancreatic and liver tissues to homeostat glucose level. Mainstream medicines used for DM are incapable of restoring normal glucose homeostasis and have side effects where medicinal plant-derived medicine administrations have been claimed to cure diabetes or at least alleviate the significant symptoms and progression of the disease by the traditional practitioners. This study focused on screening phytocompounds and their pharmacological effects on anti-hyperglycemia on Swiss Albino mice of n-hexane, ethyl acetate, and ethanol extract of both plants Mycetia sinensis and Allophylus villosus as well as the in-silico investigations. Qualitative screening of phytochemicals and total phenolic and flavonoid content estimation were performed significantly in vitro analysis. FTIR and GC-MS analysis précised the functional groups and phytochemical investigations where FTIR scanned 14, 23 & 17 peaks in n-hexane, ethyl acetate, and ethanol extracts of Mycetia sinensis whereas the n-hexane, ethyl acetate, and ethanol extracts of Allophylus villosus scanned 11 peaks, 18 peaks, and 29 peaks, respectively. In GC-MS, 24 chemicals were identified in Mycetia sinensis extracts, whereas 19 were identified in Allophylus villosus extracts. Moreover, both plants' ethyl acetate and ethanol fractioned extracts were reported significantly (p < 0.05) with concentrations of 250 mg and 500 mg on mice for oral glucose tolerance test, serum creatinine test and serum alkaline phosphatase test. In In silico study, a molecular docking study was done on these 43 phytocompounds identified from Mycetia sinensis and Allophylus villosus to identify their binding affinity to the target Alpha Glucosidase (AG) and Peroxisome proliferator-activated receptor gamma protein (PPARG). Therefore, ADMET (absorption, distribution, metabolism, excretion, and toxicity) analysis, quantum mechanics-based DFT (density-functional theory), and molecular dynamics simulation were done to assess the effectiveness of the selected phytocompounds. According to the results, phytocompounds such as 2,4-Dit-butyl phenyl 5-hydroxypentanoate and Diazo acetic acid (1S,2S,5R)-2-isopropyl-5-methylcyclohexyl obtained from Mycetia sinensis and Allophylus villosus extract possess excellent antidiabetic activities.

Comparing Jaffe and Enzymatic Methods for Creatinine Measurement at Various Icterus Levels and Their Impacts on Liver Transplant Allocation

The Model for End-Stage Liver Disease (MELD) scoring system is used to prioritize liver transplantations and assess disease severity. This includes the international normalized ratio (INR), creatinine, and total bilirubin. Since there are several ways to measure creatinine, MELD scores can produce inconsistent results. The objectives of this study were to define a valid cut-off for bilirubin interference in creatinine measurement and to assess the effects of various icteric levels on creatinine measurement and liver transplant allocation. A total of 400 serum samples were categorized into four groups based on their icteric indices and total bilirubin levels, including non-, mild, moderate, and severe icteric samples. Both chemical Jaffe and enzymatic techniques were used to determine the creatinine levels in all four groups, and the findings were compared. In parallel, serum samples from 83 liver transplant candidate patients were divided into three groups depending on their bilirubin levels and then similarly evaluated and interpreted. The MELD scores were then computed for each group and compared. In icteric samples, the enzymatic method produced higher results for the creatinine concentrations than the Jaffe method did, and the mean creatinine difference rose from 0.08 in nonicteric group to 1.95 in groups with severe icterus. In addition, the enzymatic approach yielded higher findings for creatinine and subsequently for MELD scores in patients who were liver transplant candidates. When the bilirubin concentration was above the 4 mg/dL threshold, there were differences between the approaches for both the creatinine and the MELD score (p values: 0.0001 and 0.027, respectively). The chemical Jaffe is a readily available and considerably cost-effective method for measuring creatinine. However, it is influenced by a variety of known and unknown interfering substances, and it should be applied cautiously when working with icteric samples. Alternate techniques such as the enzymatic method should be considered when the bilirubin level exceeds 4 mg/dL. Though this cut-off is instrument and kit-dependent, each laboratory is advised to have its cut-off for bilirubin interference.

Impact of model-informed precision dosing on achievement of vancomycin exposure targets in pediatric patients with cystic fibrosis

BACKGROUND

Vancomycin is commonly used to treat acute pulmonary exacerbations in pediatric patients with cystic fibrosis (CF) and a history of methicillin-resistant Staphylococcus aureus. Optimizing vancomycin exposure during therapy is essential and area under-the-curve (AUC)-guided dosing is now recommended. Model-informed precision dosing (MIPD) utilizing Bayesian forecasting is a powerful approach that can support AUC-guided dose individualization. The objective of the current study was to examine the impact of implementing an AUC-guided dose individualization approach supported via a MIPD clinical decision support (CDS) tool on vancomycin exposure, target attainment rate, and safety in pediatric patients with CF treated with vancomycin during clinical care.

METHODS

A retrospective chart review was performed in patients with CF at a single children's hospital comparing pre- and post-implementation of a MIPD approach for vancomycin supported by a cloud-based, CDS tool integrated into the electronic health record (EHR). In the pre-MIPD period, vancomycin starting doses of 60 mg/kg/day (<13 years) or 45 mg/kg/day (≥13 years) were used. Dose adjustment was guided by therapeutic drug monitoring (TDM) with a target trough 10-20 mg/L. In the post-MIPD period, starting dose and dose adjustment were based on the MIPD CDS tool predictions with a target 24 h AUC (AUC24 ) 400-600 mg*h/L. Exposure and target achievement rates were retrospectively calculated and compared. Rates of acute kidney injury (AKI) were also compared.

RESULTS

Overall, 23 patient courses were included in the pre-MIPD period and 21 patient courses in the post-MIPD period. In the post-MIPD period, an individualized MIPD starting dose resulted in 71% of patients achieving target AUC24 compared to 39% in the pre-MIPD period (p < 0.05). After the first TDM and dose adjustment, target AUC24 achievement was also higher post-MIPD versus pre-MIPD (86% vs. 57%; p < 0.05). AKI rates were low and similar between periods (pre-MIPD 8.7% vs. post-MIPD 9.5%; p = 0.9).

CONCLUSION

An MIPD approach implemented within a cloud-based, EHR-integrated CDS tool safely supported vancomycin AUC-guided dosing and resulted in high rates of target achievement.

Neurodevelopment After Neonatal Acute Kidney Injury in Very Preterm-Birth Children

Introduction

This study aimed to assess head circumference (HC) growth and neurodevelopmental outcomes in very preterm-birth children after neonatal acute kidney injury (AKI).

Methods

This longitudinal follow-up cohort included 732 very preterm neonates of gestational age <31 weeks admitted to a tertiary center between 2008 and 2020. AKI was categorized as nonoliguric and oliguric AKI based on the urine output criteria during admission. We compared the differences in death, z scores of HC (zHC) at term-equivalent age (TEA) and at corrected ages of 6, 12, and 24 months, and the neurodevelopmental outcomes at corrected age of 24 months after neonatal nonoliguric and oliguric AKI.

Results

Among the 154 neonates who developed AKI, 72 had oliguric AKI and 82 had nonoliguric AKI. At TEA, oliguric AKI, but not nonoliguric AKI, was independently associated with lower zHC than non-AKI (mean differences, -0.49; 95% confidence interval [CI], -0.92 to -0.06). Although the 3 groups were comparable in zHC at corrected ages of 6, 12, and 24 months, the oliguric AKI group, but not the nonoliguric AKI group, had a higher rate of microcephaly by corrected age of 24 months. In addition, the oliguric AKI group, but not the nonoliguric AKI group, was more likely to die (61% vs. 9%) and have neurodevelopmental impairment (41% vs. 14%) compare with the non-AKI group. After adjustment, oliguric (adjusted odds ratio [aOR], 8.97; 95% CI, 2.19-36.76), but not nonoliguric, AKI was associated with neurodevelopmental impairment.

Conclusion

Neonatal oliguric AKI is associated with neurodevelopmental impairment in very preterm-birth children. Long-term head-size and neurodevelopmental follow-up after neonatal AKI is warranted.

Biological variation of biochemical urine and serum analytes in healthy dogs

BACKGROUND

Biological variation (BV) of urinary (U) biochemical analytes has not been described in absolute terms, let alone as a ratio of the U-creatinine or fractional excretion in healthy dogs. These analytes are potential diagnostic tools for different types of kidney damage and electrolyte disorders in dogs.

OBJECTIVES

We aimed to investigate the BV of specific gravity, osmolality, creatinine, urea, protein, glucose, chloride, sodium, potassium, calcium, and phosphate in urine from healthy pet dogs.

METHODS

Blood and urine samples from 13 dogs were collected once weekly for 8 weeks. Samples were analyzed in duplicate and in randomized order. For each sample, U-analyte and serum concentrations were measured, and U-analyte/U-creatinine and fractional excretion (FE) were calculated. Components of variance, estimated by restricted maximum likelihood, were used to determine within-subject variation (CVI ), between-subject variation (CVG ), and analytical variation (CVA ). Index of individuality (II) and reference change values were calculated.

RESULTS

CVI for all urine analytes varied between 12.6% and 35.9%, except for U-sodium, U-sodium/U-Cr, and FE-sodium, which had higher CVI s (59.5%-60.7%). For U-protein, U-sodium, U-potassium, U-sodium/U-creatinine, FE-urea, FE-glucose, FE-sodium, FE-potassium, and FE-phosphate II were low, indicating that population-based RIs were appropriate. The remaining analytes had an intermediate II, suggesting that population-based RIs should be used with caution.

CONCLUSION

This study presents information on the biological variation of urinary and serum biochemical analytes from healthy dogs. These data are important for an appropriate interpretation of laboratory results.

Development and validation of the creatinine clearance predictor machine learning models in critically ill adults

BACKGROUND

In critically ill patients, measured creatinine clearance (CrCl) is the most reliable method to evaluate glomerular filtration rate in routine clinical practice and may vary subsequently on a day-to-day basis. We developed and externally validated models to predict CrCl one day ahead and compared them with a reference reflecting current clinical practice.

METHODS

A gradient boosting method (GBM) machine-learning algorithm was used to develop the models on data from 2825 patients from the EPaNIC multicenter randomized controlled trial database. We externally validated the models on 9576 patients from the University Hospitals Leuven, included in the M@tric database. Three models were developed: a "Core" model based on demographic, admission diagnosis, and daily laboratory results; a "Core + BGA" model adding blood gas analysis results; and a "Core + BGA + Monitoring" model also including high-resolution monitoring data. Model performance was evaluated against the actual CrCl by mean absolute error (MAE) and root-mean-square error (RMSE).

RESULTS

All three developed models showed smaller prediction errors than the reference. Assuming the same CrCl of the day of prediction showed 20.6 (95% CI 20.3-20.9) ml/min MAE and 40.1 (95% CI 37.9-42.3) ml/min RMSE in the external validation cohort, while the developed model having the smallest RMSE (the Core + BGA + Monitoring model) had 18.1 (95% CI 17.9-18.3) ml/min MAE and 28.9 (95% CI 28-29.7) ml/min RMSE.

CONCLUSIONS

Prediction models based on routinely collected clinical data in the ICU were able to accurately predict next-day CrCl. These models could be useful for hydrophilic drug dosage adjustment or stratification of patients at risk.

TRIAL REGISTRATION

Not applicable.

Performance and pitfalls of the tools for measuring glomerular filtration rate to guide chronic kidney disease diagnosis and assessment

Accurate diagnosis, classification and risk stratification for chronic kidney disease (CKD) allow for early recognition and delivering optimal care. Creatinine-based glomerular filtration rate (GFR), urinary albumin: creatinine ratio (UACR) and the kidney failure risk equation (KFRE) are important tools to achieve this, but understanding their limitations is important for optimal implementation.When accurate GFR is required (eg, chemotherapy dosing), GFR is measured using an exogenous filtration marker. In routine clinical practice, in contrast, estimated GFR (eGFR) from serum creatinine (SCr), calculated using the enzymatic method±UACR, is recommended. Limitations of SCr include non-GFR determinants such as muscle mass, diet and tubular handling. An alternative or additional endogenous filtration marker is cystatin C, which can be used alongside SCr for confirmatory testing of CKD. However, its role in the UK is more limited due to concerns regarding false positive results.The recommended creatinine-based eGFR equation in the UK is the CKD Epidemiology Collaboration 2009 equation. This was recently updated to a race-neutral 2021 version and demonstrated reduced bias in people of Black ethnicity, but has not been validated in the UK. Limitations are extremes of age, inaccuracy at greater GFRs and reduced generalisability to under-represented ethnicity groups.The KFRE (based on age, sex, SCr and UACR) has recently been developed to help determine 2-year and 5-year risk of progression to end-stage kidney disease. It has been validated in over 30 countries and provides meaningful quantitative information to patients. However, supporting evidence for their performance in ethnic minority groups and kidney diseases such as glomerulonephritis remains modest.In conclusion, early identification, risk stratification of kidney disease and timely intervention are important to impact kidney disease progression. However, clinician awareness of the limitations and variability of creatinine, cystatin C and the eGFR equations, is key to appropriate interpretation of results.

Application of SERS-based nanobiosensors to metabolite biomarkers of CKD

A clinical diagnosis of chronic kidney disease (CKD) is commonly achieved by estimating the serum levels of urea and creatinine (CR). Given the limitations of the conventional diagnostic assays, it is imperative to seek alternative, economical strategies for the detection of CKD-specific biomarkers with high specificity and selectivity. In this respect, surface-enhanced Raman spectroscopy (SERS) can be regarded as an ideal choice. SERS signals can be greatly amplified by noble metal nanoparticles (e.g., gold nanoparticles (GNPs)) of numerous sizes, shapes, and configurations to help achieve ultra-sensitive single molecule-level detection at 10^-15 M (up to 10 orders of magnitude more sensitive than fluorescence-based detection). The irregular geometry of GNPs with spike-like tips, dimers, and aggregates with small nanogaps (i.e., due to plasmon coupling such as Raman hot spots) play a pivotal role in enhancing the specificity and sensitivity of SERS. This review critically outlines the performance of SERS-based biosensors in the ultrasensitive detection of CKD biomarkers in various body fluids in terms of basic quality assurance parameters (e.g., limit of detection, figure of merit, enhancement factor, and stability of the biosensor). Moreover, the challenges and perspectives are described with respect to the expansion of such sensing techniques in practical clinical settings.

Non-enzymatic electrochemical detection of creatinine based on a glassy carbon electrode modified with a Pd/Cu2O decorated polypyrrole (PPy) nanocomposite: an analytical approach

The major constraints of standard enzymatic biosensors are poor long-term storage stability and high cost. Hence, there is extensive research towards fabrication of reliable enzymeless biosensors based on nanomaterials. In this paper, we present the development of an enzymeless electrochemical biosensor for highly precise detection of creatinine. This involves the use of a simple yet effective alternative to the commonly utilized Pd/Cu₂O/PPy nanocomposite, which was characterized by different analytical methods. The present electrochemical sensor provides a wide detection range (0.1 to 150 μM), low detection limit (0.05 μM) and high sensitivity (0.207 μA), and is capable of detecting the creatinine level in human urine samples, which are inexpensive. The results are reproducible, and the sensor is stable. The sensor demonstrates good electrocatalytic activity and selectivity towards the detection of creatinine in the presence of various other similar biological entities. When compared to other existing counterparts, the electrocatalytic behaviour of the present sensor is comparable, if not better. So, the present electrochemical sensor for creatinine might be employed as a long-term diagnostic alternative.

Evaluation of the Accuracy of Cr and BUN Using the ABL90 FLEX PLUS Blood Gas Analyzer and the Equivalence of Candidate Specimens for Assessment of Renal Function

BACKGROUND

The ABL90 FLEX PLUS (Radiometer) is a blood gas analyzer that also provides creatinine (Cr) and blood urea nitrogen (BUN) results. We assessed the accuracy of the ABL90 FLEX PLUS to measure Cr and BUN and find suitable candidate specimens against primary specimens (heparinized whole-blood (H-WB)).

METHODS

Paired H-WB, serum, and sodium-citrated whole-blood (C-WB) samples (105) were collected. The Cr and BUN levels in the H-WB using the ABL90 FLEX PLUS were compared with those of the serum using four automated chemistry analyzers. The suitability of the candidate specimens was assessed at each medical decision level according to the CLSI guideline EP35-ED1.

RESULTS

The respective mean differences of the ABL90 FLEX PLUS for the Cr and BUN were below -0.10 and -3.51 mg/dL compared to the other analyzers. The systematic differences between the serum and the H-WB at the low, medium, and high medical decision levels were all 0% for Cr, but those of the C-WB were -12.96%, -11.81%, and -11.30%, respectively. Regarding imprecision, the SD_serum/SD_H-WB ratios at each level were 0.14, 1.41, and 0.68, whereas the SD_C-WB/SD_H-WB ratios were 0.35, 2.00, and 0.73, respectively.

CONCLUSIONS

The ABL90 FLEX PLUS provided Cr and BUN results comparable with the four widely used analyzers. Among the candidates, the serum was suitable for Cr testing using the ABL90 FLEX PLUS, while the C-WB did not satisfy the acceptance criteria.

Rat resistance to rheumatoid arthritis induction as a function of the early-phase adrenal-pineal crosstalk

Chronic inflammatory diseases are triggered by causal stimuli that might occur long before the appearance of the symptoms. Increasing evidence suggests that these stimuli are necessary but not always sufficient to induce the diseases. The murine model of type II collagen emulsified in Freund's incomplete adjuvant (collagen-induced arthritis) to induce rheumatoid arthritis (RA) follows this pattern as some animals do not develop the chronically inflamed phenotype. Considering that in the immune-pineal axis (IPA) theory adrenal-pineal cross-talk adjusts early phases of inflammatory processes, we investigated whether differences in IPA activation could explain why some animals are resistant (RES) while others develop RA. We observed a similar increase in 6-sulfatoxymelatonin (aMT6s) excretion from day 3 to 13 in both RES and RA animals, followed by a significant decrease in RA animals. This pattern of aMT6s excretion positively correlated with plasma corticosterone (CORT) in RES animals. Additionally, RA animals presented a lower aMT6s/CORT ratio than saline-injected or RES animals. Plasmatic levels of tumour necrosis factor were similar in both groups, but interleukin (IL)-1β and monocyte chemotactic protein 1 (MCP-1) levels were lower in RES compared to RA animals. IL-2 and IL-4 were decreased in RES animals compared to saline-injected animals. The aMT6s/CORT ratio inversely correlated with the paw thickness and the inflammatory score (levels of IL-1β, MCP-1, IL-2 and IL-4 combined). Thus, adrenocortical-pineal positive interaction is an early defence mechanism for avoiding inflammatory chronification. KEY POINTS: Immune-pineal axis imbalance is observed in early-phase rheumatoid arthritis development. Only resistant animals present a positive association between adrenal and pineal hormones. The 6-sulfatoxymelatonin/corticosterone ratio is decreased in animals that develop rheumatoid arthritis. The inflammatory score combining the levels of nocturnal interleukin (IL)-1β, monocyte chemotactic protein 1, IL-2 and IL-4 presents a very strong positive correlation with the size of inflammatory lesion. The 6-sulfatoxymelatonin/corticosterone ratio presents a strong negative correlation with the inflammatory score and paw oedema size.

Allograft function and muscle mass evolution after kidney transplantation

BACKGROUND

Advanced chronic kidney disease is associated with muscle wasting, but how glomerular filtration rate (GFR) recovery after kidney transplantation is associated with muscle mass is unknown.

METHODS

We took advantage of the simultaneous measurement of GFR (using iohexol plasma clearance; ioGFR) and creatinine excretion rate (a surrogate marker of muscle mass; CER) performed 3 months after transplantation and at a later time point at our institution to investigate the interplay between allograft function, muscle mass, and outcome in kidney transplant recipients.

RESULTS

Between June 2005 and October 2019, 1319 successive kidney transplant recipients (mean age 50.4 ± 14.6; 38.7% female) underwent GFR measurement at our institution 3 months after kidney transplantation. CER (CER₃ ) and ioGFR (ioGFR₃ ) were 7.7 ± 2.6 μmol/min and 53 ± 17.1 mL/min/1.73 m² , respectively. Multivariable analysis identified female gender, older donor and recipient age, reduced body mass index, coronary disease, dialysis history, proteinuria, and reduced ioGFR₃ as independent predictors of low CER₃ (ioGFR₃ : β coefficient 0.19 [95% confidence interval 0.14 to 0.24]). A total of 1165 patients had a subsequent CER measurement after a median follow-up of 9.5 months. Of them, 373 (32%) experienced an increase in CER > 10%, while 222 (19%) showed a CER decrease of more than 10%. Multivariable analysis adjusted for CER₃ and other confounders identified ioGFR₃ as an independent predictor of CER at follow-up (β coefficient 0.11 [95% confidence interval 0.07 to 0.16]). In multivariable Cox analysis, reduced CER at 3 months or at follow-up were consistently associated with mortality (hazard ratio [95% confidence interval] at 3 months: 0.82 [0.74 to 0.91]; at follow-up: 0.79 [0.69 to 0.99]) but not with graft loss.

CONCLUSIONS

Glomerular filtration rate recovery is a determinant of muscle mass variation after kidney transplantation. Early interventions targeting muscle mass gain may be beneficial for kidney transplant recipients.

Stability of trace element concentrations in frozen urine - Effect on different elements of more than 10 years at - 80 °C

BACKGROUND

Analysis of urinary trace elements is widely used in Human Biology, especially in occupational and environmental biomonitoring. Collections of urine samples are of great interest for those studying trace elements but many of them are actually unused, in part perhaps because of a lack of knowledge about the stability of trace element concentrations under such storage conditions. The aim of this study was to evaluate the impact of a long-term frozen storage on the measurement of the urinary concentration of 10 trace elements.

METHOD

Forty-eight urinary samples were re-analysed by inductively coupled plasma mass spectrometry (ICP-MS) for the quantification of As, Cd, Co, Cr, Mn, Ni, Pb, Sb, Tl, and Zn, after 11-13 years of frozen storage at - 80 °C.

RESULTS

A slight water loss likely occurred, even at - 80 °C, but seems to be compensated by using creatinine-adjusted concentrations. Concentrations of As, Cd, Pb, Tl, Zn, and possibly Mn, did not suffer from major modification during storage, while the plastic container likely contaminated samples with Sb. The technological evolution over 13 years may have affected some results, especially those with lower concentrations, and must be taken into account when comparing data over time.

CONCLUSION

This study provides some promising preliminary data on the stability of trace element concentrations during long-term frozen storage, and some evidence that urine samples in existing biobanks remain a valuable resource, even if they were collected many years ago.

Assessment of Serum Free Light Chains as a Marker of Diabetic Nephropathy; A Cross-Sectional Study in the Kumasi Metropolis

Aims

Although traditional tests such as serum urea, creatinine, and microalbuminuria have been widely employed in the diagnosis of diabetic nephropathy, their sensitivity and accuracy are limited because kidney damage precedes the excretion of these biomarkers. This study investigated the role of serum free light chains in the disease manifestation of diabetic nephropathy.

Materials and Methods

Using a cross-sectional design we recruited 107 diabetes mellitus out-patients who visited the Diabetes and Renal Disease Clinics at the Komfo Anokye Teaching Hospital, Manhyia District Hospital, and Suntreso Government Hospital all in Ghana from November 2019 to February 2020. Five (5) mls of blood was collected from each participant and analyzed for fasting blood glucose (FBG) urea, creatinine, immunoglobulin free light chains. Urine samples were obtained and analyzed for albumin. Anthropometric characteristics were also measured. Data were analyzed using descriptive analysis, analysis of variance (ANOVA) test, Tukey HSD post hoc, and Kruskal Wallis test. Chi-squared test was used to examine if there are significant associations with the indicators of interest. In addition, Spearman’s correlation was used to test for associations between appropriate variables. Receiver operating characteristic analysis (ROC) was also performed to assess the diagnostic performance of free light chains.

Results

The mean age of studied participants was 58.2 years (SD: ± 11.1), 63.2% were females and most of the participants were married (63.0%). The mean FBG of the studied participants was 8.0mmol/L (SD: ± 5.86), and the average duration of diabetes mellitus (DM) was 11.88 years (SD: ± 7.96). The median serum Kappa, Lambda, and Kappa: Lambda ratios for the studied participants were 18.51 (15.63-24.18), 12.19(10.84-14.48), and 1.50(1.23-1.86) respectively. A positive correlation was observed between albuminuria and; Kappa (rs=0.132; p=0.209), and Lambda (rs=0.076; p=0.469). However, a negative correlation was observed between albuminuria and K: L ratio (rs=-0.006; p=0.956).

Conclusions

The current study observed an increasing trend in the levels of free light chains and degree of diabetic nephropathy, although not statistically significant. The exploration of serum free light chains as a better marker of diabetic nephropathy showed very promising results but further studies are required to elucidate its predictive value as a diagnostic tool for diabetic nephropathy.

A disposable printed amperometric biosensor for clinical evaluation of creatinine in renal function detection

In clinical practice, sera creatinine level is regarded as a crucial biomarker for the diagnosis, staging and monitoring of kidney disease. An amperometric biosensor is rapid, accurate, and cost-effective, with a portability and a simple operation. Herein, we report for the firsttime a disposable, printed amperometric biosensor for the clinical evaluation of creatinine in renal function detection. The sensor is constructed based on Prussian blue/carbon-graphite paste as the working electrode and the immobilization of creatinine amidohydrolase, creatine amidinohydrolase and sarcosine oxidase. The creatinine biosensor shows a linear detection range from 0.05 to 1.4 mM with a detection time of about 3 min. In addition, the sensor shows a high stability that can maintain above 86% of the initial activity after being stored for over 4 months. Moreover, the sensor shows almost the same results as those with the Jaffe method for measuring the real blood samples. We anticipate that the creatinine biosensor could be widely used in the medical and healthcare areas, especially for at-home testing and onsite medical examinations.

Exploiting a strong coupling regime of organic pentamer surface plasmon resonance based on the Otto configuration for creatinine detection

The sandwiched material-analyte layer in the surface plasmon resonance (SPR)-Otto configuration emulates an optical cavity and, coupled with large optical nonlinearity material, the rate of light escaping from the system is reduced, allowing the formation of a strong coupling regime. Here, we report an organic pentamer SPR sensor using the Otto configuration to induce a strong coupling regime for creatinine detection. Prior to that, the SPR sensor chip was modified with an organic pentamer, 1,4-bis[2-(5-thiophene-2-yl)-1-benzothiopene]-2,5-dioctyloxybenzene (BOBzBT₂). To improve the experimental calibration curve, a normalisation approach based on the strong coupling-induced second dip was also developed. By using this procedure, the performance of the sensor improved to 0.11 mg/dL and 0.36 mg/dL for the detection and quantification limits, respectively.

A copper nanoclusters probe for dual detection of microalbumin and creatinine

A fluorescent probe based on glutathione-capped copper nanoclusters (GSH-CuNCs) was developed for the detection of dual targets, human serum albumin (HSA) and creatinine, in human urine. The GSH-CuNCs were synthesized by a one-pot green method using ascorbic acid as a reducing agent. The detection of HSA was in a turn-on mode via electrostatic interaction in a basic condition while the detection of creatinine was in a turn-off mode via non-covalent bonding in an acidic condition. Under optimal conditions, the linear range and detection limit of HSA were 5.0 nM to 150 nM and 1.510 ± 0.041 nM, while those of creatinine were 30 μM to 1000 μM and 13.0 ± 1.0 μM. This easily fabricated nanocluster probe provided a fast response with high sensitivity, and good selectivity. Recoveries from urine samples were in the range of 81.44 ± 0.25 to 109.22 ± 0.57% for HSA and 80.57 ± 0.16 to 109.0 ± 0.10% for creatinine. The urinary analytical results from the fluorescent probe were in good agreement (P > 0.05) to those obtained from immunoturbidimetric and enzymatic methods, signifying the excellent performance of this sensing system.

OUP accepted manuscript

Background

Methods

Results

Conclusions

Recurrence monitoring for ovarian cancer using a cell phone-integrated paper device to measure the ovarian cancer biomarker HE4/CRE ratio in urine

Ovarian cancer has a poor cure rate and rates of relapse are high. Current recurrence detection is limited by non-specific methods such as blood testing and ultrasound. Based on reports that human epididymis four (HE4) / creatinine (CRE) ratios found in urine are elevated in ovarian cancers, we have developed a paper-based device that combines lateral flow technology and cell phone analysis to quantitatively measure HE4/CRE. Surrogate samples were used to test the performance over clinically expected HE4/CRE ratios. For HE4/CRE ratios of 2 to 47, the percent error was found to be 16.0% on average whether measured by a flatbed scanner or cell phone. There was not a significant difference between the results from the cell phone or scanner. Based on published studies, error in this method was less than the difference required to detect recurrence. This promising new tool, with further development, could be used at home or in low-resource settings to provide timely detection of ovarian cancer recurrence.

Quantification of normetanephrine in canine urine using ELISA: evaluation of factors affecting results

Catecholamine release increases in dogs with pheochromocytomas and in situations of stress. Although plasma catecholamines degrade rapidly, their metabolites, normetanephrine (NME) and metanephrine (ME), are stable in acidified urine. Our aim was to verify a human urine ELISA kit for the quantification of NME and ME in canine urine and to determine the effects on metabolite stability of sampling time (morning or midday) and day (ordinary or day spent in a clinic). We analyzed 179 urine samples from 17 healthy dogs. For NME, the mean intra-assay CV was 6.0% for all samples and 4.3% for the canine control; inter-assay CVs were 3.3, 3.8, and 12% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 90-101%. For ME, mean intra-assay CV was 6.5% for samples and 9.0% for the canine control; inter-assay CVs were 12.7, 7.2, and 22.5% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 85-89%. Dilution recovery was unsatisfactory for both metabolites. Based on our verification results, NME was selected for remaining analyses. We found no effect on NME concentrations of acidification or room temperature storage for up to 24 h. The NME:creatinine ratio was higher after the first of 3 clinic days compared to the same morning (111.2 ± 5.5 vs. 82.9 ± 5.3; p < 0.0001), but not on the other days. NME verification results were generally superior to ME. Dilution studies were unsatisfactory for both metabolites. Given that NME was stable without acidification at room temperature, urine samples can be collected at home. The clinic environment can cause higher NME:creatinine ratios, especially in unaccustomed dogs.

Performance evaluation of all analytes on the epoc® Blood Analysis System for use in hospital surgical and intensive care units

Objective

To evaluate the performance of the epoc hand-held analyzer against the RAPIDPoint 500 blood gas analyzer and laboratory analyzers where applicable.

Methods

Venous or arterial whole blood samples collected in balanced heparinized syringes were obtained from 69 patients (35 females, 34 males) predominantly (77%) from the surgical unit and intensive care unit (ICU). Method comparison was performed for all analytes on the epoc System against the RAPIDPoint 500 Blood gas analyzer or laboratory analyzers where applicable. Results: Mean bias was <5% for blood gases, electrolytes, lactate and glucose. Hematocrit showed a bias of -6.76% (95% CI ​= ​-8.91, - 4.61) compared to the HemataSTAT-II method, whereas calculated total hemoglobin showed a bias of 1.51% (95% CI ​= ​-1.04, 4.06) against the Sysmex XN-10 hematology analyzer. Creatinine showed the largest bias relative to laboratory analyzers, Abbott Architect c8000 Jaffe method (13.54%, 95% CI ​= ​5.43, 21.65) and Roche Cobas c702 enzymatic method (30.01%, 95% CI ​= ​12.64, 47.38). Conclusions: The epoc system is fit for use in the surgical and ICU setting for the measurement of all analytes except for creatinine.

Urine Nitric Oxide Is Lower in Parents of Autistic Children

Parents raising children with autism spectrum disorder (ASD) usually carry on their daily life under tremendous stress, but limited empirical research has been devoted to this population. It is known that parents' health status directly impacts therapeutic outcome of ASD children. As an important regulator in cardiovascular, nervous and immune systems, nitric oxide (NO) levels haven't been reported in parents of ASD children yet. In this study, we measured urine nitrite and nitrate from 43 ASD parents (ASD-P), and 43 healthy adults in the same range of age (Control) who didn't have any ASD descendants. Comparison between the ASD-P and Control groups showed that NO 2 - , NO 3 - , and NO 2 - / NO 3 - were all significantly lower in the ASD-P group. Analysis on the interaction effect of sex and group indicated that urine NO 3 - of mothers in ASD-P was lower than that in females of the Control group, but no significant difference was observed between males in both groups. It is for the first time that urine nitric oxide metabolites (nitrite, nitrate) levels were precisely reported to differentiate parents of autistic children from other adults without ASD descendants. This phenomenon suggests that parents (especially mothers) of autistic children might have experienced more mental and physical stressors, which led to decreased NO levels during metabolism. Further investigations are necessary to uncover the etiology of low urine NO among parents of autistic children.

Association Between 25(OH)Vitamin D, HbA1c and Albuminuria in Diabetes Mellitus: Data From a Population-Based Study (VIDAMAZON)

BACKGROUND

The effect of glycemic control on diabetic kidney disease (DKD) is well known. Recent evidence has suggested that Vitamin D (VD) may have a nephroprotective effect in diabetes, but the relationship between VD, glycemic control, and albuminuria has yet to be clarified.

OBJECTIVE

Evaluate the relationship between 25-hydroxy-vitamin D [25(OH)D], HbA1c, and albuminuria in Diabetes Mellitus (DM).

PATIENTS AND METHODS

Cross-sectional study with 1576 individuals with DM who had 25(OH)D, HbA1c, and albuminuria levels measured. Patients with abnormal creatinine levels were excluded, in order to avoid interference on VD levels by impaired kidney function.

RESULTS

Patients with HbA1c ≥7% had lower 25(OH)D when compared to patients with HbA1c <7% (29.7 ± 10.2 vs 28.1 ± 9.9 ng/ml, p = 0.003) and 25(OH)D levels seems to predict 1.5% of HbA1c behavior. The 25(OH)D concentrations in patients with normoalbuminuria were higher than the levels observed in those with micro or macroalbuminuria (29.8 ± 9.0 vs 26.8 ± 8.6 and 25.1 ± 7.6, respectively, p = 0.001), patients who had 25(OH)D <20 ng/ml and 25(OH)D <30 ng/ml were at a higher risk of presenting albuminuria [OR = 2.8 (95% CI = 1.6 - 4.9), p<0.001, and OR = 2.1 (95% CI = 1.3 - 4.6), p<0.001, respectively]. In our regression model, albuminuria was influenced by HbA1c (r² = 0.076, p<0.00001) and 25(OH)D (r² = 0.018, p = 0.002) independently.

CONCLUSION

Our study found an association between vitamin D levels, HbA1c and DKD. Additionally, our data suggest that the association between urinary albumin excretion and vitamin D levels is independent of glycemic control in patients with diabetes. Even though our patients presented normal creatinine levels, it is necessary further prospective studies to confirm if this association precedes or not the loss of renal function.

Creatinine-Based Renal Function Assessment in Pediatric Drug Development: An Analysis Using Clinical Data for Renally Eliminated Drugs

The estimated glomerular filtration rate (eGFR) equations based on serum creatinine (SCR) have been used for pediatric dose adjustment in drug labeling. This study evaluated the performance of those equations in estimating individual clearance of drugs that are predominantly eliminated by glomerular filtration, using clinical data from the renally eliminated drugs gadobutrol, gadoterate, amikacin, and vancomycin. The eGFR was compared with the observed drug clearance (CL) in 352 pediatric patients from birth to 12 years of age. Multiple eGFR equations overestimated the drug CL on average, including the original and bedside Schwartz equations, which showed an average eGFR/CL ratio between 1 and 3. Further analysis with bedside Schwartz equation showed a higher eGFR/CL ratio in the subjects with a lower SCR or CL. Supraphysiological eGFR as high as 380 mL/min/1.73 m² was obtained using the bedside Schwartz equation for some of the subjects, most of whom are children < 2 years of age with SCR < 0.2 mg/dL. Excluding the subjects with supraphysiological eGFR from the analysis did not change the overall trend of overestimation. In conclusion, Schwartz equations led to an overestimation of drug clearance for the drugs evaluated. When greater precision is required in predicting eGFR for pediatric patients, such as in drug dosing, revised k constants for the Schwartz equation or new methods of glomerular filtration rate estimation may be necessary.

Implant-forming polymeric 19F MRI-tracer with tunable dissolution

Magnetic resonance imaging (MRI) using ¹⁹F-based tracers has emerged as a promising multi-purpose noninvasive diagnostic tool and its application requires the use of various ¹⁹F-based tracers for the intended diagnostic purpose. In this study, we report a series of double-stimuli-responsive polymers for use as injectable implants, which were designed to form implants under physiological conditions, and to subsequently dissolve with different dissolution rates (t_1/2 ranges from 30 to more than 250 days). Our polymers contain a high concentration of fluorine atoms, providing remarkable signal detectability, and both a hydrophilic monomer and a pH-responsive monomer that alter the biodistribution properties of the implant. The implant location and dissolution were observed using ¹⁹F MRI, which allows the anatomic extent of the implant to be monitored. The dissolution kinetics and biocompatibility of these materials were thoroughly analyzed. No sign of toxicity in vitro or in vivo or pathology in vivo was observed, even in chronic administration. The clinical applicability of our polymers was further confirmed via imaging of a rat model by employing an instrument currently used in human medicine.

Measurement of serum creatinine levels with liquid chromatography-tandem mass spectrometry: comparison with Jaffe and enzymatic methods

Objectives

Our aim was to validate a mass spectrometric creatinine method and compare this method with Jaffe and enzymatic serum creatinine methods.

Methods

90 samples were included. The levels were classified into three groups according to serum creatinine results as Group 1: Lower (n=30) (0.16–0.59 mg/dL), Group 2: Normal (n=30) (0.62–1.18 mg/dL) and Group 3: Higher (n=30) (1.33–3.88 mg/dL). Jaffe and enzymatic creatinine measurements were performed on the Beckman Coulter AU5800 autoanalyzer.

Results

Serum creatinine was linear from 0.039 up to 10 mg/dL, CV and bias values were ranged between 1.9–3.8% and 2–15%. Correlation coefficients were 0.990 (95% confidence interval 0.984–0.993), 0.992 (95% confidence interval 0.988–0.995) and 0.994 (95% confidence interval 0.991–0.996) for LC-MS/MS-Enzymatic, LC-MS/MS-Jaffe and Enzymatic-Jaffe, respectively.

Conclusions

Although, Jaffe method for serum creatinine measurement is still much more practical and cheap, so in use for routine practice, tandem mass spectrometric detection of serum creatinine can be used as an accurate and specific method for verification of discordant clinical results, existence of possible interferences and serum levels under 0.5 mg/dL creatinine results such as pediatric or pregnant populations.

Evaluation of the impact of delayed centrifugation on the diagnostic performance of serum creatinine as a baseline measure of renal function before antiretroviral treatment

Background

The measurement of serum creatinine is a standard requirement of the medical management of people living with HIV. Renal dysfunction is common, both as a complication of HIV-infection and as a result of its treatment. The detection of abnormal renal function before the start of antiretroviral therapy will impact patient management and the outcome of treatment.

Objectives

This study aimed to determine if a time delay in the centrifugation of serum samples affected the creatinine level and the estimated glomerular filtration rate as recorded on the analytical platforms used in the laboratory.

Methods

Twenty-two (n = 22) HIV-positive, newly diagnosed and treatment-naïve patients were randomly recruited from Alexandra Health Clinic, Johannesburg, South Africa. Serum samples were centrifuged at six time intervals following receipt of the sample viz. < 4 h (baseline), 6 h, 24 h, 48 h, 72 h and 96 h. Creatinine concentrations were measured on the Roche platform utilising the enzymatic and kinetic Jaffe methods. Whole blood samples were also analysed with the Abbott i-STAT point-of-care instrument. The estimated glomerular filtration rate was calculated using the Cockcroft Gault, CKD-Epidemiology Collaboration and Modified Diet and Renal Disease v3/4 equations.

Results

At baseline (< 4 h) there was good agreement between the enzymatic and kinetic Jaffe methods: bias 1.7 µmol/l. The enzymatic and i-STAT creatinine concentrations were stable over 96 h viz. changes of 1.8% and 5.7%. However, from 24 h onwards agreement between the enzymatic and kinetic Jaffe methods was poor with the latter measuring 43.7 µmol/l higher than the enzymatic method at 96 h. Creatinine concentrations measured with the kinetic Jaffe method increased significantly in samples centrifuged after 6 h (p < 0.001, 61.7% change), and resulted in a 95% decline in eGFR at 96 h as determined with the CKD-Epidemiology Collaboration equation.

Conclusion

The analysis of serum creatinine using the isotope dilution mass spectrometry traceable kinetic Jaffe method is unreliable if performed on samples centrifuged ≥ 6 h after collection. The raised creatinine concentration can affect clinical decisions such as renal functional assessment, choice of antiretroviral drug or regimen, and the dose and frequency of medication.

Sodium-Glucose Cotransporter 2 Inhibitors and Kidney Outcomes: True Renoprotection, Loss of Muscle Mass or Both?

Inhibitors of sodium-glucose cotransporter 2 (SGLT2) have emerged as practice-changing treatments for patients with type 2 diabetes, reducing both the risk of cardiovascular events and kidney events. However, regarding the latter, caution is warranted, as these kidney endpoints are defined using glomerular filtration rate estimations based on creatinine, the non-enzymatic product of creatine residing in muscles. Creatinine-based estimations of the glomerular filtration rate are only valid if the treatment has no effect on changes in muscle mass over time. Yet, circumstantial evidence suggests that treatment with SGLT2 inhibitors does result in a loss of muscle mass, rendering serum creatinine-based kidney endpoints invalid. Currently, it cannot be excluded that the described renoprotective effect of SGLT2 inhibitors is in part or in whole the consequence of a loss of muscle mass. Post-hoc analyses of existing trials or new trials based on kidney function markers independent of muscle mass can provide more definitive answers on the proposed renoprotective effects of SGLT2 inhibitors.

Bisphenol A Exposure Enhances Endometrial Stromal Cell Invasion and Has a Positive Association with Peritoneal Endometriosis

Results of previous epidemiology studies on BPA exposure and endometriosis (EMs) risk were inconsistent, and were limited by inappropriate control selection, incorrect BPA detection method, and the generalization of different subtypes of EMs. Upregulated matrix metalloproteinase (MMP) 2 and MMP9 are involved in the development of EMs. We conducted a case-control study among 120 EMs patients and 100 healthy women to evaluate the relationships between BPA exposure and MMP2, MMP9 expressions, and the risk of EMs subtypes. Besides, we used human endometrial stromal cell lines (HESCs) to investigate the underlying mechanisms. Creatinine-adjusted urinary BPA concentrations were positively correlated with serum MMP2, MMP9 levels, and the risk of peritoneal EMs (third vs lowest quartile: OR 4.92, 95% CI 1.47, 16.50; fourth versus lowest quartile: OR 3.70, 95% CI 1.07, 12.74, P_trend = 0.030). The risk of peritoneal EMs increased approximately tenfold when creatinine-adjusted urinary BPA concentration was 2 μg/g. In vitro study found that BPA exposure increased MMP2, MMP9 expressions in a dose-dependent manner. The effects of BPA on HESCs could be blocked by G protein-coupled estrogen receptor (GPER) inhibitor or mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) inhibitor. This study provides evidence that BPA exposure promotes peritoneal EMs, and raises a concern about the potential toxicity of BPA on the female reproductive system.