The e-cigarette category is evolving rapidly, providing consumers with a variety of formats, ranging from cig-alike products to larger, high-powered modular devices. When generating an in vitro assessment approach across such diverse products, dosimetry considerations are paramount. In this article, we have compared nicotine quantification techniques in two studies using a Vitrocell VC 10 Smoking Robot to generate aerosols from different ecigarettes. In Study 1, a 3R4F reference cigarette and four different commercially available e-cigarettes were compared: puff-by-puff nicotine concentration was quantified at the same e-cigarette puffing regime (CRM No81) or with different puff durations, (2 or 3 seconds), comparing 3R4F puff-by-puff yields following ISO and HCI smoking regimes. In Study 2, 3R4F and one e-cigarette were assessed for puff-by-puff nicotine concentration in different locations (China and United Kingdom) comparing different nicotine quantification methods with gas chromatography-mass spectrometry and UPLC-MS/MS used in the two laboratories. Study 1 showed that 3R4F cigarette delivers different nicotine concentrations across the different regimes and puff number, supporting the nicotine methodology; e-cigarettes tested generated different amounts of nicotine across the devices tested, but showed consistent puff-by-puff delivery per device. Study 2 showed positive agreement between results across two different laboratories utilizing different methods for nicotine quantification; statistical analysis, combining all interlaboratory variables, indicated that laboratory differences and the interaction of laboratory and puff number were not significant (p = 0.067 and 0.960, respectively). These studies will add further knowledge to support the in vitro assessment of novel nicotine products, providing reliability and assurance in the area of in vitro dosimetry.
Histone acetylation is one of the most important posttranslational modifications that contribute to transcriptional initiation and chromatin remodeling. In our previous study, we enhanced sperm chromatin remodeling within the bovine sperm injection-derived androgenentic (SpI-AG) embryos by sperm pretreatment, and thereby improved their early developmental competence. In this study, we found that blastocyst development of SpI-AG embryos could be elevated by the histone deacetylase inhibitor (HDACi). First, we optimized the efficacy of two histone deacetylase inhibitors [trichostatin A (TSA) and Scriptaid (SCR)] in a dose (0, 5, 10, 20, 50, and 100 nM for TSA; 0, 50, 100, 200, 300, and 500 nM for SCR, respectively) and time-dependent (0, 10, 15, 20, and 25 h) manner on the developmental capacity of these embryos. Furthermore, we quantitatively assessed the alterations in histone H3 and H4 overall acetylation levels and blastocyst quality of SpI-AG embryos by immunofluorescence staining. We found a significantly improved morula and blastocyst development rate of SpI-AG embryos at a mild dose of TSA (20 nM) or SCR (200 nM) for 15 h after embryo activation. Furthermore, both HDACi noticeably increased the levels of acetylated histone H3 and H4 in SpI-AG blastocyst embryos, whereas, SCR treatment improved the quality of blastocysts when compared with control group. In conclusion, HDACi is beneficial for early development of bovine SpI-AG embryos and can be used to improve the efficiency of its in vitro production.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.