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Acute p.o. administration of absolute ethanol (10 ml/kg) to fasted mice would produce extensive renal failure. Pretreatment with p.o. administration of propolis ethanol extract (PEE) could prevent such renal failure effectively and dose dependently. This renal protective effect of PEE may be contributed, at least in part, to its antioxidative activity. The maximal antioxidative effect against absolute ethanol (AE)-induced renal failure could be observed 1 hour after PEE administration. In order to further investigate the renal protective mechanism of PEE, lipid peroxidation and superoxide scavenging activity were conducted in vivo. PEE exhibited dose-dependent antioxidative effects on lipid peroxidation in mice renal homogenate. Results indicated that mice with acute renal failure have higher malonic dialdehyde (MDA) levels compared with those in PEE administered mice. It was concluded that the renal protective mechanism of PEE could be contributed, at least in part, to its prominent superoxide scavenging effect; hence, it could protect, indirectly, the kidney from superoxide-induced renal damages.

In this study, the cholic acid-capped gold nanoclusters (CC-AuNCs) were prepared via a microwave-assisted approach and were used as a novel fluorescence probe for detection of creatinine. The CC-AuNCs in solution can emit strong green fluorescence under UV light and the fluorescence intensity can increase with creatinine concentration in the solution because of the aggregation of CC-AuNCs. On the basis of these facts, the fluorescence assay for creatinine was developed. The linear working range is $1.0\times 10^{-10}$–$1.0\times 10^{-7}$M with a detection limit of $7.54\times 10^{-12}$M according to signal/noise ratio of 3:1. This fluorescence assay for creatinine has a low detection limit, wide linear range and good selectivity. Furthermore, it can be successfully applied to the detection of creatinine in human urine and serum samples. Thus, this CC-AuNC-based fluorescence assay for creatinine might be of great importance in early diagnosis and therapy of kidney disease.

In this paper, in vivo spectra from 23 patients’ blood samples with various Creatinine (Cr) concentration levels ranging from 0.96 to 12.5 mg/dL were measured using Fourier transform near-infrared spectrometer (FT-NIRS) and spectrum quantitative analysis method. Since Cr undergoes passive filtration, it serves as a key biomarker of kidneys function via the estimation of glomerular filtration rate. Thus, increased blood Cr concentration reflects impaired renal function. After spectra pre-processing and outlier exclusion, a spectral model was developed based on partial least squares regression (PLSR) method, wherein Cr concentrations correlated with filtered NIR spectra across several peaks, where Cr is known to absorb NIR light. Several statistical metrics were applied to estimate the model efficiency during data analysis. Comparison of spectra-derived concentrations to reference Cr measurements by the current gold-standard Jaffe’s method held in hospital lab revealed a Cr prediction accuracy of 1.64mg/dL with good correlation of $R=0.9$. Bland-Altman plots were used to compare between our calculations and reference lab values and reveal minimal bias between the two. The finding presented the potential of FT-NIRS coupled with PLSR technique for Cr determination.

Creatinine (Cr) is a biochemical waste molecule generated from muscle metabolism and primarily cleared from the bloodstream by the kidneys. If kidney function declines, Cr levels in the blood tend to increase. Therefore, Cr serves as an indicator of kidney function. In this work, we present a simple method for the rapid screening for impaired renal function based on the subject’s Cr concentration. In our setup, broadband white light is delivered to a finger clamp through a fiber-optic cable to illuminate the patient’s finger. The light is transmitted through the finger and collected by a second optical fiber coupled to a visible–near-infrared (VisNIR) spectrometer which covers the spectral range from 400nm to 1100nm. During the calibration process, the transmitted spectra acquired from 60 patients were measured. An average was calculated using the peak level of the transmitted, diffused intensity at three different wavelengths to create a “Cr intensity index”. Patients were divided into five groups according to their Cr concentration levels, ranging from 1mg/dL to 13mg/dL. Our observations indicated that each group featured a unique spectral fingerprint. Next, we tested the index on 20 patients not included in the calibration procedure (unknown samples). We were able to classify patients into groups according to their Cr level with moderate prediction accuracy ($R^2=0.55$) and mean screening error of up to 16%. Future efforts will evaluate the accuracy of this approach with larger patient populations representing a broad range of Cr concentration. Still, this preliminary work is an essential step toward developing this useful noninvasive Cr screening platform using NIR light spectroscopy.

Creatinine level in urine is an important biomarker for renal function diseases, such as renal failure, glomerulonephritis, and chronic nephritis. The Au@MIL-101(Fe) was prepared by in situ growth of Au nanoparticles in MIL-101(Fe) as a selective SERS substrate. The Au@MIL-101(Fe) offers the great local surface plasmon resonance (SPR) effect due to gold nanoparticles aggregation inside metal-organic frameworks. The framework structure could enrich trace target samples and drag them into SPR hot spots. The optimal Au@MIL-101(Fe) composite substrate is used for analyzing creatinine in urine and the limit of detection is down to 0.1$\mu$mol/L and a linear relationship is ranging from 1$\mu$mol/L to 100$\mu$mol/L.