[A fluorescence method based on malachite green/aptamer for detection of ochratoxin A in traditional Chinese medicines].

A label-free fluorescence method based on malachite green/aptamer was developed for the detection of ochratoxin A(OTA) in traditional Chinese medicines. Malachite green itself exhibits weak fluorescence. Upon interaction with the aptamer specific to OTA, the G-quadruplex structure of the aptamer provides a protective microenvironment for malachite green, which significantly enhances its fluorescence signal. After OTA is added, preferential binding occurs between the aptamer and OTA, and malachite green will be released from the aptamer, which weakens the fluorescence signal. According to this principle, this paper established a fluorescence method with the aptamer of OTA as the recognition element and malachite green as the fluorescent probe for the detection of OTA in traditional Chinese medicines. The key experimental factors such as the concentrations of metal ions, aptamer, and malachite green were optimized to improve the performance of the method. OTA was detected under the optimal experimental conditions, and the results showed that with the increase in OTA concentration, the fluorescence signal gradually weakened. Within the range of 20-1 000 nmol·L~(-1), the OTA concentration was linearly correlated with the fluorescence signal ratio ΔF/F(ΔF=F_0-F, where F_0 is the fluorescence signal of aptamer/malachite green, and F is the fluorescence signal of OTA/aptamer/malachite green), with R~2 of 0.995. The limit of detection of the established method was 7.1 nmol·L~(-1). Furthermore, three substances structurally similar to OTA and two mycotoxins that may coexist with OTA were selected for experiments, which aimed to examine the cross-reactivity and specificity of the established method. The cross-reactivity experiments demonstrated that the interferers did not significantly affect the fluorescence signal of the detection system. The specificity experiments revealed that when mycotoxins were mixed with OTA, the fluorescence signal generated by the mixture closely resembled that of OTA itself. The results indicated that even in the presence of interferents, the established method remained unaffected and demonstrated excellent specificity. Additionally, this method exhibited remarkable reproducibility and stability. In the case of simple centrifugation and dilution of traditional Chinese medicine samples(Puerariae Lobatae Radix, Sophorae Flavescentis Radix, and Periplocae Cortex), the OTA detection method was applicable, with recovery rates ranging from 91.5% to 121.3%. Notably, this approach does not need complex pretreatment of traditional Chinese medicines while offering simple operation, low detection costs, and short detection time. Furthermore, by incorporating aptamers into the quality evaluation of traditional Chinese medicines, this method expands the application scope of aptamers.

The Serum Exosome Derived MicroRNA-135a, -193b, and -384 Were Potential Alzheimer's Disease Biomarkers.

OBJECTIVE: MicroRNAs (miRs) are attractive molecules to be considered as one of the blood-based biomarkers for neurodegenerative disorders such as Alzheimer's disease (AD). The goal of this study was to explore their potential value as biomarkers for the diagnosis of AD. METHODS: The expression levels of exosomal miR-135a, -193b, and -384 in the serum from mild cognitive impairment (MCI), dementia of Alzheimer-type (DAT), Parkinson's disease with dementia (PDD), and vascular dementia (VaD) patients were measured with a real-time quantitative reverse transcriptase PCR (qRT-PCR) method. RESULTS: Both serum exosome miR-135a and miR-384 were up-regulated while miR-193b was down-regulated in serum of AD patients compared with that of normal controls. Exosome miR-384 was the best among the three miRs to discriminate AD, VaD, and PDD. Using the cut-off value could better interpret these laboratory test results than reference intervals in the AD diagnosis. ROC curve showed that the combination of miR-135a, -193b, and -384 was proved to be better than a particular one for early AD diagnosis. CONCLUSION: Our results indicated that the exosomal miRs in the serum were not only potential biomarker of AD early diagnosis, but might also provide novel insights into the screen and prevention of the disease.

[Research progress on MAPK signal pathway in the pathogenesis of osteoarthritis].

Mitogen-activated protein kinases (MAPKs) signal is one of the important ways in eukaryotic cell,which adjusts and controls the structure and function of the cell. MAPKs in eukaryotes include p38, ERK, JNK and ERK5, etc. With the deepening research,we found that the activation of p38, ERK, JNK signal pathways were closely related with osteoarthritis (OA) cartilage injury. MAPKs are the key signaling systems involved in the production of matrix metalloproteinases and the regulation of cartilage cell proliferation, apoptosis and differentiation. Expecially the matrix metalloproteinases can accelerate the degradation of articular cartilage. So it has been the new spot in pathogenesis of osteoarthritis study.

Adaptive thresholding with inverted triangular area for real-time detection of the heart rate from photoplethysmogram traces on a smartphone.

Photoplethysmogram (PPG) signals acquired by smartphone cameras are weaker than those acquired by dedicated pulse oximeters. Furthermore, the signals have lower sampling rates, have notches in the waveform and are more severely affected by baseline drift, leading to specific morphological characteristics. This paper introduces a new feature, the inverted triangular area, to address these specific characteristics. The new feature enables real-time adaptive waveform detection using an algorithm of linear time complexity. It can also recognize notches in the waveform and it is inherently robust to baseline drift. An implementation of the algorithm on Android is available for free download. We collected data from 24 volunteers and compared our algorithm in peak detection with two competing algorithms designed for PPG signals, Incremental-Merge Segmentation (IMS) and Adaptive Thresholding (ADT). A sensitivity of 98.0% and a positive predictive value of 98.8% were obtained, which were 7.7% higher than the IMS algorithm in sensitivity, and 8.3% higher than the ADT algorithm in positive predictive value. The experimental results confirmed the applicability of the proposed method.