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Objective@#To compare the effectiveness of qualitative and quantitative fecal immunochemical tests (FIT) in identifying colorectal cancer, so as to provide insights into perfecting screening strategies for colorectal cancer.@*Methods@#Participants in the Colorectal Cancer Screening Program for Key Populations in Zhejiang Province from May 2020 to December 2021 were recruited, and their demographic information, lifestyle and disease history were collected through a questionnaire survey. Qualitative or quantitative FIT along with a questionnaire-based risk assessment were employed as the initial screening tests. Individuals who were positive in any FIT or had high-risk assessment results were required to attend a subsequent colonoscopy examination. The positive rate, detection rate of colorectal cancer, positive predictive value and number of colonoscopies required were compared between qualitative and quantitative FITs, and stratified analyses by gender and age were conducted.@*Results@#Totally 4 099 769 participants were included. The qualitative FIT group included 3 574 917 individuals, yielding a positive rate of 11.35%, a detection rate of 1.19%, a positive predictive value of 0.48% and 83.84 colonoscopies required to detect one cancer case. The quantitative FIT group involved 524 852 individuals, yielding a positive rate of 6.70%, a detection rate of 2.31%, a positive predictive value of 1.01% and 43.23 colonoscopies required to detect one cancer case. The quantitative FIT group showed significantly higher detection rate of colorectal cancer, higher positive predictive value and less number of colonoscopies required compared to the qualitative FIT group (all P<0.05). The same results were obtained after stratification by gender and age.@*Conclusion@#Compared to qualitative FIT, quantitative FIT improves the detection of colorectal cancer and reduces the workload of colonoscopy examinations, making it more suitable for colorectal cancer screening in large-scale populations.
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Background: Conopeptides from cone snail venom have aroused great interest related to the discovery of novel bioactive candidates, due to their excellent prospects for the treatment of various health problems such as pain, addiction, psychosis and epilepsy. In order to explore novel biopeptides, we investigated the structure and function of five novel conopeptides isolated from the venom of Conus marmoreus from South China Sea. Methods: C. marmoreus crude venom was prepared, fractionated and purified by HPLC system. The primary sequences of the five novel disulfide-poor conopeptides Mr-1 to Mr-5 were identified by comprehensive analysis of de novo MALDI-TOF tandem mass spectrometry and Edman degradation data. In order to investigate their function, these five conopeptides were synthesized by Fmoc-SPPS chemistry, and their biological effects at several heterologous rat nicotinic acetylcholine receptor (nAChR) subtypes (α1β1δε, α3β2, α3β4, α4β2) were determined by electrophysiological technique. Results: Five novel disulfide-poor conopeptides were identified and named as follows: Mr-1 (DWEYHAHPKPNSFWT), Mr-2 (YPTRAYPSNKFG), Mr-3 (NVIQAPAQSVAPP NTST), Mr-4 [KENVLNKLKSK(L/I)] and Mr-5 [NAVAAAN(L/I)PG(L/I)V]. None of them contains a disulfide bond. The sequences of conopeptides Mr-2 to Mr-5 do not belong to any category of the known disulfide-poor conopeptides. No significant activity against the above nAChR subtypes were observed for the five conopeptides at 100 µM. Conclusion: We purified and structurally characterized five novel disulfide-poor conopeptides from C. marmoreus crude venom and first investigated their nAChR inhibitory effects. This work expanded our knowledge on the structure and function of disulfide-poor conopeptides from this cone snail venom.(AU)