1.Study on the analytic method of synthetic cannabinoid JWH-122 by the high performance liquid chromatography
Cuiying MIAO ; Zunlei QIAN ; Linfeng ZHANG ; Wanfeng ZHAI
Chinese Journal of Forensic Medicine 2016;31(6):563-566
Objective To establish an effective method for determination of synthetic cannabinoid JWH-122 by the high-performance liquid chromatography (HPLC), which is controled by China’s Regulations on non-clinical narcotic and psychoactive drug. Methods Methanol-deionized water (50%-50%) was used as mobile phase for gradient elution. In addition to the initial concentration in organic phase, gradient steepness, column temperature, flow rate and other chromatographic conditions, the determine wavelengths were tested so as to ifnd out optimal experimental conditions. Linearity range and speciifcity were tested under optimal conditions, and actual samples were used to verify the method established. Results Under the condition of ultraviolet spectrum detection wavelength at 221nm, initial concentration of 70%, organic phase gradient steepness of 0.5%/min, lfow rate at 1.2 ml/min and column temperature of 30℃,excellent linearity of JWH-122 was observed at 0.002mg/mL-0.1mg/mL and the detection limit (S/N≥3) was 0.1μg/mL. The test of actual samples suggested that JWH-122 was able to be well separated from the sample under the optimal conditions. Conclusion Our method has advantages of rapidity, sensitivity, accuracy and excellent separation efifciency, and is capable of the detection of synthetic cannabinoid JWH-122 of the novel “spice” drugs.
2.Xenotransplantation of Microencapsulated Rabbit Parathyroid Tissue for Treatment of Hypoparathyroidism In Rats
Changlu GAO ; Linfeng WU ; Yingxin LIU ; Bo ZHAI
Chinese Journal of Bases and Clinics in General Surgery 2003;0(03):-
Objective To investigate the effect of xenotransplantation of microencapsulated rabbit parathyroid tissue in different sites in rats for the treatment of hypoparathyroidism. Methods The parathyroid glands from Wistar rats were removed to make them aparathyroid. Ultimately, sixteen rats were included because their serum calcium values were continuously below 1.6 mmol/L. We also encapsulated the cultured rabbit parathyroid tissue with alginate-BaCl2 microcapsule. According to the transplantation sites, rats were randomly divided into two groups: renal adipose microcapsule group and peritoneal microcapsule group, eight in each group. Encapsulated rabbit parathyroid tissues were then transplanted accordingly to different microcapsule groups. The calcium serum contents were examined on 5,15,25,35,45,55 and 65 d respectively after transplantation and the grafts were observed through electron microscope on the 65 d in particular. Results The calcium contents after transplantation in renal adipose microcapsule group restored to normal and the observation outcomes of grafts showed that they survived well. The calcium contents of posttransplantation in peritoneal group also restored to normal with an exception that it dropped to a level lower than 1.6 mmol/L on the 65 d. Electron microscope also showed that there were necrotic tissues in the center and only a few cells survived on the edge of the grafts. Within peritoneal microcapsule group, the values were significantly lower than others taken at different phases. Conclusion Microencapsulated rabbit parathyroid tissue that was xenotransplanted into rats can survive and function without administration of immunodepressant. There are significant differences of calcium contents at varying phases between two transplantation sites, which demonstrate that renal adipose may be an optimal site for microcapsule xenotransplantation.
3.Study on hydrophilicity and degradability of polyvinyl alcohol/polylactic acid blend film.
Hualin WANG ; Mingang SHENG ; Linfeng ZHAI ; Yanhong LI
Journal of Biomedical Engineering 2008;25(1):139-142
Based on casting and solvent evaporation method, the degradable PLA/PVA blend film was prepared with polylactic acid (PLA) and polyvinyl alcohol (PVA) as raw material. The moisture absorbability, water absorbability and degradability of the polylactic acid/polyvinyl alcohol (PLA/PVA) blend film were studied; also the degradation mechanism of blend film was investigated. The results showed that the moisture absorption and water absorption of blend film decreased as the concentration of PLA increased. The degradation process of blend film in the normal saline is conducted by stepwise. At the forepart, the degradation of PLA played an important role, while PVA was the main degradation substance later. The solvent acidity could catalyze the degradation of PLA, and degradation of PLA was always turning from noncrystalline region to crystalline region. PVA had abilities to accelerate the degradation of PLA by increasing the hydrophilicity of the blend film and by breaking the crystallinity of PLA. Therefore, the hydrophilicity and degradability of PLA/PVA blend film can be controlled in a certain range by adjusting the proportion of PLA and PVA.
Biocompatible Materials
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chemistry
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Biodegradation, Environmental
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Hydrophobic and Hydrophilic Interactions
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Lactic Acid
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chemistry
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Polyesters
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chemistry
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Polymers
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chemistry
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Polyvinyl Alcohol
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chemistry
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Water
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chemistry
4.A machine learning model for diagnosing acute pulmonary embolism and comparison with Wells score, revised Geneva score, and Years algorithm
Linfeng XI ; Han KANG ; Mei DENG ; Wenqing XU ; Feiya XU ; Qian GAO ; Wanmu XIE ; Rongguo ZHANG ; Min LIU ; Zhenguo ZHAI ; Chen WANG
Chinese Medical Journal 2024;137(6):676-682
Background::Acute pulmonary embolism (APE) is a fatal cardiovascular disease, yet missed diagnosis and misdiagnosis often occur due to non-specific symptoms and signs. A simple, objective technique will help clinicians make a quick and precise diagnosis. In population studies, machine learning (ML) plays a critical role in characterizing cardiovascular risks, predicting outcomes, and identifying biomarkers. This work sought to develop an ML model for helping APE diagnosis and compare it against current clinical probability assessment models.Methods::This is a single-center retrospective study. Patients with suspected APE were continuously enrolled and randomly divided into two groups including training and testing sets. A total of 8 ML models, including random forest (RF), Na?ve Bayes, decision tree, K-nearest neighbors, logistic regression, multi-layer perceptron, support vector machine, and gradient boosting decision tree were developed based on the training set to diagnose APE. Thereafter, the model with the best diagnostic performance was selected and evaluated against the current clinical assessment strategies, including the Wells score, revised Geneva score, and Years algorithm. Eventually, the ML model was internally validated to assess the diagnostic performance using receiver operating characteristic (ROC) analysis.Results::The ML models were constructed using eight clinical features, including D-dimer, cardiac troponin T (cTNT), arterial oxygen saturation, heart rate, chest pain, lower limb pain, hemoptysis, and chronic heart failure. Among eight ML models, the RF model achieved the best performance with the highest area under the curve (AUC) (AUC = 0.774). Compared to the current clinical assessment strategies, the RF model outperformed the Wells score ( P = 0.030) and was not inferior to any other clinical probability assessment strategy. The AUC of the RF model for diagnosing APE onset in internal validation set was 0.726. Conclusions::Based on RF algorithm, a novel prediction model was finally constructed for APE diagnosis. When compared to the current clinical assessment strategies, the RF model achieved better diagnostic efficacy and accuracy. Therefore, the ML algorithm can be a useful tool in assisting with the diagnosis of APE.