ABSTRACT
Objective To compare the effectiveness of loop-mediated isothermal amplification (LAMP) assay and microscopic examinations for detection of Schistosoma japonicum infections in Oncomelania hupensis in transmission-interrupted regions, so as to provide insights into the optimization of snail surveillance tools in these regions. Methods Four hilly schistosomiasis-endemic villages where transmission interruption was achieved were selected in Heqing County of Yunnan Province as the study villages, including Xinzhuang and Gule villages in hilly regions and Lianyi and Yitou villages in dam regions. Snail survey was performed by means of systematic sampling combined with environmental sampling in July 2018. All captured snails were identified for S. japonicum infections using microscopy. In addition, 10 to 20 snails were randomly sampled from each snail habitat following microscopy, numbered according to environments and subjected to LAMP assay. The positive rate of settings with S. japonicum-infected snails was compared among villages. Results A total of 7 949 living snails were captured from 83 snail habitats in 4 villages, and no S. japonicum infection was detected in snails. There were 226 mixed samples containing 1 786 snails subjected to LAMP assay, and positive LAMP assay was found in 3 mixed samples from 3 snail habitats in 2 dam villages. The positive rates of settings with S. japonicum-infected snails were comparable between Lianyi Village (one setting) and Yitou Village (2 set tings) (5.89% vs. 14.29%, P = 0.344). However, the overall positive rate of settings with S. japonicum-infected snails was significantly higher in dam villages (9.67%, 3/31) than in hilly villages (0) (P = 0.048). Conclusions LAMP assay is more sensitive to detect S. japonicum infections in O. hupensis than conventional microcopy method, which may serve as a supplementary method for detection of S. japonicum infections in O. hupensis in high-risk snail habitats in hilly transmission-interrupted regions.
ABSTRACT
The article aims to study the effect and mechanism of shear stress on eicosanoids produced by the metabolism of polyunsaturated fatty acids in endothelial cells. First, human umbilical vein endothelial cells were treated by control (Static), laminar shear stress (LSS) and oscillatory shear stress (OSS) for 6 h. Then the endothelial cells were incubated with fresh M199 medium for 3 h, and the cell culture medium was collected. Ultra-performance liquid chromatography-mass spectrometer was used to detect the level of eicosanoid metabolites secreted by endothelial cells. The results showed that under different shear stress, the level of eicosanoid metabolites were changed significantly. We found 10 metabolites were significantly up-regulated by OSS compared with those in LSS group, including PGD2, PGE2, PGF2α and PGJ2 produced by cyclooxygenase; 11-HETE, 15-HETE, 13-HDoHE produced by lipoxygenase or spontaneous oxidation; 12,13-EpOME, 9,10-EpOME, 9,10-DiHOME produced by cytochrome P450 oxidase and soluble epoxide hydrolase. The transcription levels of these up-regulated eicosanoids metabolic enzyme-related genes were also increased in vitro and in vivo. These results indicate that OSS may promote the increase of metabolites by up-regulating the transcription level of metabolic enzyme-related genes, which playing a key role in the development of atherosclerosis. This study reveals the effect of shear stress on eicosanoid metabolism in endothelial cells, which provides a novel supplement to the systems biology approach to study systemic hemodynamics.