No abstract

Background: Urinary proteins are predictive and prognostic markers for diabetes nephropathy. Conventional methods for the quantification of urinary proteins, however, are time-consuming, and most require radioactive labeling. We designed a label-free piezoelectric quartz crystal microbalance (QCM) immunosensor array to simultaneously quantify 4 urinary proteins. Methods: We constructed a 2 ؋ 5 model piezoelectric immunosensor array fabricated with disposable quartz crystals for quantification of microalbumin, ␣ 1 -microglobulin, ␤ 2 -microglobulin, and IgG in urine. We made calibration curves after immobilization of antibodies at an optimal concentration and then evaluated the performance characteristics of the immunosensor with a series of tests. In addition, we measured 124 urine samples with both QCM immunosensor array and immunonephelometry to assess the correlation between the 2 methods. Results: With the QCM immunosensor array, we were able to quantify 4 urinary proteins within 15 min. This method had an analytical interval of 0.01-60 mg/L. The intraassay and interassay imprecisions (CVs) were <10%, and the relative recovery rates were 90.3%-109.1%. Nonspecificity of the immunosensor was insignificant (frequency shifts <20 Hz). ROC analyses indicated sensitivities were >95.8% and, specificities were

Trypsin inhibitor (TI), an important antinutritional factor present in soybean [Glycine max (L.) Merr.] seeds, prevents animal protein digestibility. Accurately determining seed TI concentration is essential for screening soybean breeding lines to select genotypes with low TI. A colorimetric assay is widely used to measure TI activity in soybean seeds. This bioassay is time consuming, expensive, and has repeatability issues. This study developed a high‐performance liquid chromatography (HPLC) method as a high‐throughput, less expensive, and more reliable assay to quantify Kunitz trypsin inhibitor (KTI), the major TI, in soybean seeds. We extracted KTI using sodium acetate buffer, separated on a Poros R2/H perfusion column and detected at 220 nm. The HPLC method was compared with two popular enzymatic bioassays using 100 soybean lines. For the bioassays, TI was extracted using HCl or NaOH extractants and determined according to Kakade et al. (1974). The KTI from the HPLC method ranged from 0.52 to 12.15 mg g−1 with an average of 5.25 mg g−1 and a limit detection of 0.05 mg g−1. The recovery of KTI in spiked soybean samples was 82.33%. The KTI data from HPLC and both bioassays were strongly correlated (r = 0.82 and 0.80, p ≤ 0.0001). The CVs of KTI data (66.20% for HPLC, 18.84 and 32.55% for bioassays) suggest that the HPLC method is capable of detecting a wider range of KTI quantities and providing a better sensitivity for quantifying KTI in soybean seed samples.

The dopamine level in the brain and the mesolimbick dopaminergic system are responsible for nicotine addiction. In the present study, extracellular dopamine in nucleus accumbens was collected by a brain microdialysis technique. Also a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with a gradient elution procedure was developed for a precise determination of dopamine in brain dialysate. The retention time of dopamine was about 11.32 min. The linear range was 20 -1000 pg/mL. The limit of detection (LOD) and the limit of qualification (LOQ) were 5 and 20 pg/mL, respectively. The recovery ranged from 98.2 to 109.0%, and both the intra-RSD and inter-RSD were below <9%, respectively. The probe recovery for dopamine in this brain microdialysis experiment was about 25%. Finally, the dopamine concentrations in the rat brain microdialysates were determined, and the pharmacokinetics of extracellular dopamine in the brain nucleus accumbens after an intravenous injection of nicotine was successfully evaluated.

Background: Recently, more and more men who have sex with men (MSM) look for casual partners through online dating platforms in China. However, most are unable to know their partners' HIV and other sexually transmitted diseases (STD) statuses, leading to the rapid increase in HIV infection among Chinese MSM. Effective partner notification is urgently needed to increase the risk awareness of MSM and prevent HIV and other STDs transmission. However, the traditional intervention mainly targets to the HIV-positive MSM and the effect is not promising. Our study aims to provide Internet-based partner notification, along with a series of health services for HIV-negative MSM to protect them from HIV and other STDs. Methods: A pragmatic stepped wedge cluster randomized controlled trial design is used to evaluate the effectiveness of a new intervention paradigm, which aims to reduce HIV and other STDs incidences among MSM in China. Through integrating a mobile health (mHealth) service application (app) to the current HIV and other STDs prevention and control methods, the new paradigm provides partner notification of HIV, syphilis, hepatitis B, and hepatitis C statuses. A total of 6172 MSM in 16 districts of Beijing, China will be recruited and randomized to sequentially receive partner notification intervention through the app at 6-month intervals. The primary outcomes are HIV incidence and the additional cost of the intervention. The secondary outcomes include incidences of syphilis, hepatitis B, and hepatitis C, disease transmission social networks, testing adherence, knowledge of HIV and STDs control, health self-responsibility awareness, changes of high risk behaviors and other related outcomes. The generalized linear mixed models (GLMM) will be used to analyze the differences of outcomes in the control period and in the intervention period.