Mutation Rates of TGFBR2 and ACVR2 Coding Microsatellites in Human Cells with Defective DNA Mismatch Repair

Microsatellite instability promotes colonic tumorigenesis through generating frameshift mutations at coding microsatellites of tumor suppressor genes, such as TGFBR2 and ACVR2. As a consequence, signaling through these TGFβ family receptors is abrogated in DNA Mismatch repair (MMR)-deficient tumors. How these mutations occur in real time and mutational rates of these human coding sequences have not previously been studied. We utilized cell lines with different MMR deficiencies (hMLH1−/−, hMSH6−/−, hMSH3−/−, and MMR-proficient) to determine mutation rates. Plasmids were constructed in which exon 3 of TGFBR2 and exon 10 of ACVR2 were cloned +1 bp out of frame, immediately after the translation initiation codon of an enhanced GFP (EGFP) gene, allowing a −1 bp frameshift mutation to drive EGFP expression. Mutation-resistant plasmids were constructed by interrupting the coding microsatellite sequences, preventing frameshift mutation. Stable cell lines were established containing portions of TGFBR2 and ACVR2, and nonfluorescent cells were sorted, cultured for 7–35 days, and harvested for flow cytometric mutation detection and DNA sequencing at specific time points. DNA sequencing revealed a −1 bp frameshift mutation (A9 in TGFBR2 and A7 in ACVR2) in the fluorescent cells. Two distinct fluorescent populations, M1 (dim, representing heteroduplexes) and M2 (bright, representing full mutants) were identified, with the M2 fraction accumulating over time. hMLH1 deficiency revealed 11 (5.91×10−4) and 15 (2.18×10−4) times higher mutation rates for the TGFBR2 and ACVR2 microsatellites compared to hMSH6 deficiency, respectively. The mutation rate of the TGFBR2 microsatellite was ∼3 times higher in both hMLH1 and hMSH6 deficiencies than the ACVR2 microsatellite. The −1 bp frameshift mutation rates of TGFBR2 and ACVR2 microsatellite sequences are dependent upon the human MMR background

The utility of human security: Sovereignty and humanitarian intervention

'Human security' is a promising but still underdeveloped paradigmatic approach to understanding contemporary security politics. We argue that tension between those embracing the politics of development and those supporting the human security paradigm has intensified because the transnational dimensions embodied within the latter approach have been under-assessed. The idea of 'threat' also needs to be identified with more precision for the human security concept to accrue analytical credibility. We focus on how transnational behaviour addresses the central human security problems of vulnerability and immediacy. Human security's utility for confronting crisis is also evaluated via the application of two case studies of humanitarian intervention: the 1994 multinational operation in Haiti and the 1999 intervention in East Timor. We conclude that, while general security politics includes both domestic and international issues, human security allows us to transcend sovereign prerogatives and to address emerging transregional threats more effectively

Hypertension in pregnancy and adverse outcomes among low-risk nulliparous women expectantly managed at or after 39 weeks: a secondary analysis of a randomised controlled trial

OBJECTIVE: To evaluate whether hypertensive disorders of pregnancy (HDP) among low-risk nulliparous women expectantly managed at or after 39 weeks of gestation are associated with adverse outcomes. DESIGN: Secondary analysis of a randomised trial. SETTING: Multicentre, USA. POPULATION: Individuals in the expectantly managed group who delivered on or after 39 weeks. METHODS: Multivariable analysis to estimate adjusted relative risks (aRR) for binomial outcomes, adjusted odds ratios (aOR) for multinomial outcomes and 95% CI. MAIN OUTCOME MEASURES: Composite adverse maternal outcome including placental abruption, pulmonary oedema, postpartum haemorrhage, postpartum infection, venous thromboembolism or intensive care unit admission. Secondary outcomes included a composite of perinatal death or severe neonatal complications, mode of delivery, small and large for gestational age and neonatal intermediate or intensive unit length of stay. RESULTS: Of the 3044 women randomised to expectant management in the original trial, 2718 (89.3%) were eligible for this analysis, of whom 373 (13.7%) developed HDP. Compared with participants who remained normotensive, those who developed HDP were more likely to experience the maternal composite (12% versus 6%, aRR 1.84, 95% CI 1.33-2.54) and caesarean delivery (29% versus 23%, aOR 1.32, 95% CI 1.01-1.71). Differences between the two groups were not significantly different for the adverse perinatal composite (7% versus 5%, aRR 1.38, 95% CI 0.92-2.07) or for other secondary outcomes. CONCLUSION: Almost 14% of low-risk nulliparous individuals expectantly managed at 39 weeks developed HDP, and were more likely to experience adverse maternal outcomes compared with those who did not develop HDP. TWEETABLE ABSTRACT: Almost 14% of low-risk nulliparous individuals expectantly managed at 39 weeks developed hypertensive disorders of pregnancy, and were more likely to experience adverse maternal outcomes compared with those who did not develop hypertensive disorders