No Meta-analytic Evidence for Risks due to Prenatal Magnetic Resonance Imaging in Animal Models.

BACKGROUND: Magnetic resonance imaging (MRI) is a powerful, noninvasive tool for both clinical practice and research. Though the safety of MRI has been endorsed by many professional societies and government bodies, some concerns have remained about potential risk from prenatal MRI. Case-control animal studies of MRI scanning during gestation and effects on offspring are the most direct test available for potential risks. We performed a meta-analysis of extant animal studies of prenatal MRI examining reproductive and offspring outcomes. METHODS: Relevant articles were identified through PubMed search and citation searching of known articles and review papers. Eighteen relevant studies were identified with case-control designs of prenatal scanning conducted in vivo with mammalian species using MRI-relevant field strength. Standardized mean difference effect sizes were analyzed across k = 81 outcomes assessed across 649 unexposed dams, 622 exposed dams, 3024 unexposed offspring, and 3328 exposed offspring using a multilevel meta-analytic approach that clustered effect sizes within publications. RESULTS: The meta-analysis indicated no significant evidence for a deleterious effects of prenatal MRI (standardized mean difference = 0.17, 95% CI [-0.19, 0.54], t80 = 0.94, p = .35) across outcomes. Similarly, no effects were observed when separately examining the 4 most commonly assessed outcomes: birth weight, litter size, fetal viability, and physical malformations (p > .05). CONCLUSIONS: Case-control mammalian animal studies indicate no significant known risks of prenatal MRI to reproductive outcomes or offspring development. This finding is largely mirrored in human research, though the lack of randomized case-control designs limits direct comparison. The current findings provide additional support to the prevailing consensus that prenatal MRI poses no known risk to offspring.

Structural Characterization, Antioxidant and Antitumor Activities of the Two Novel Exopolysaccharides Produced by Debaryomyces hansenii DH-1.

Exopolysaccharides produced by edible microorganisms exhibit excellent constructive physicochemical and significant biological activity, which provide advantages for the food or pharmaceutical industries. Two novel exopolysaccharides produced by Debaryomyces hansenii DH-1 were characterized, named S1 and S2, respectively. S1, with a molecular weight of 34.594 kDa, primarily consisted of mannose and glucose in a molar ratio of 12.19:1.00, which contained a backbone fragment of α-D-Manp-(1→4)-α-D-Manp-(1→2)-α-D-Glcp-(1→3)-α-D-Manp-(1→3)-ß-D-Glcp-(1→4)-ß-D-Manp-(1→. S2, with a molecular weight of 24.657 kDa, was mainly composed of mannose and galactose in a molar ratio of 4.00:1.00, which had a backbone fragment of α-D-Manp-(1→6)-ß-D-Manp-(1→2)-α-D-Manp-(1→4)-α-D-Galp-(1→3)-ß-D-Manp-(1→6)-α-D-Manp-(1→. Both S1 and S2 exhibited good thermal stability and potent hydroxyl radical scavenging activity, with ~98%. Moreover, S1 possessed an additional strong iron-reducing capacity. In vitro antitumor assays showed that S1 and S2 significantly inhibited the proliferation of Hela, HepG2, and PC-9 cancer cells. Moreover, PC-9 was more sensitive to S1 compared with S2. The above results indicate that S1 and S2 have great potential to be utilized as natural antioxidants and candidates for cancer treatment in the food and pharmaceutical industries.