Because RNA lacks strong intrinsic fluorescence, it has proven challenging to track RNA molecules in real time. To address this problem and to allow the purification of fluorescently tagged RNA complexes, we have selected a high affinity RNA aptamer called RNA Mango. This aptamer binds a series of thiazole orange (fluorophore) derivatives with nanomolar affinity, while increasing fluorophore fluorescence by up to 1,100-fold. Visualization of RNA Mango by single-molecule fluorescence microscopy, together with injection and imaging of RNA Mango/fluorophore complex in C. elegans gonads demonstrates the potential for live-cell RNA imaging with this system. By inserting RNA Mango into a stem loop of the bacterial 6S RNA and biotinylating the fluorophore, we demonstrate that the aptamer can be used to simultaneously fluorescently label and purify biologically important RNAs. The high affinity and fluorescent properties of RNA Mango are therefore expected to simplify the study of RNA complexes.
Objective To identify obstetric and other risk factors for urinary incontinence that occurs during pregnancy or after childbirth.Design Questionnaire survey of women.Setting Maternity units in Aberdeen (Scotland), Birmingham (England) and Dunedin (New Zealand).Population A total of 3405 primiparous women with singleton births delivered during 1 year.Methods Questionnaire responses and obstetric case note data were analysed using multivariate analysis to identify associations with urinary incontinence.Main outcome measures Urinary incontinence at 3 months after delivery first starting in pregnancy or after birth.Results The prevalence of urinary incontinence was 29%. New incontinence first beginning after delivery was associated with older maternal age (oldest versus youngest group, OR 2.02, 95% CI 1.35-3.02) and method of delivery (caesarean section versus spontaneous vaginal delivery, OR 0.28, 95% CI 0.19-0.41). There were no significant associations with forceps delivery (OR 1.18, 95% CI 0.92-1.51) or vacuum delivery (OR 1.16, 95% CI 0.83-1.63). Incontinence first occurring during pregnancy and still present at 3 months was associated with higher maternal body mass index (BMI > 25, OR 1.68, 95% CI 1.16-2.43) and heavier babies (birthweight in top quartile, OR 1.56, 95% CI 1.12-2.19). In these women, caesarean section was associated with less incontinence (OR 0.39, 95% CI 0.27-0.58) but incontinence was not associated with age.Conclusions Women have less urinary incontinence after a first delivery by caesarean section whether or not that first starts during pregnancy. Older maternal age was associated with new postnatal incontinence, and higher BMI and heavier babies with incontinence first starting during pregnancy. The effect of further deliveries may modify these findings.
Objective To investigate the prevalence of persistent and long term postpartum urinary incontinence and associations with mode of first and subsequent delivery.Design Longitudinal study.Setting Maternity units in Aberdeen (Scotland), Birmingham (England) and Dunedin (New Zealand).Population Women (4214) who returned postal questionnaires three months and six years after the index birth.Methods Symptom data were obtained from both questionnaires and obstetric data from case-notes for the index birth and the second questionnaire for subsequent births. Logistic regression investigated the independent effects of mode of first delivery and delivery mode history.Main outcome measures Urinary incontinence-persistent (at three months and six years after index birth) and long term (at six years after index birth).Results The prevalence of persistent urinary incontinence was 24%. Delivering exclusively by caesarean section was associated with both less persistent (OR = 0.46, 95% CI 0.32-0.68) and long term urinary incontinence (OR = 0.50, 95% CI 0.40-0.63). Caesarean section birth in addition to vaginal delivery, however, was not associated with significantly less persistent incontinence (OR 0.93, 95% CI 0.67-1.29). There were no significant associations between persistent or long term urinary incontinence and forceps or vacuum extraction delivery. Other significantly associated factors were increasing number of births and older maternal age.Conclusions The risk of persistent and long term urinary incontinence is significantly lower following caesarean section deliveries but not if there is another vaginal birth. Even when delivering exclusively by caesarean section, the prevalence of persistent symptoms (14%) is still high.
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