Racism and teacher training : a curriculum study

M.Ed. (Multiculturalism and Education)Please refer to full text to view abstrac

Biochemical characterization and DNA repair pathway interactions of Mag1-mediated base excision repair in Schizosaccharomyces pombe

The Schizosaccharomyces pombe mag1 gene encodes a DNA repair enzyme with sequence similarity to the AlkA family of DNA glycosylases, which are essential for the removal of cytotoxic alkylation products, the premutagenic deamination product hypoxanthine and certain cyclic ethenoadducts such as ethenoadenine. In this paper, we have purified the Mag1 protein and characterized its substrate specificity. It appears that the substrate range of Mag1 is limited to the major alkylation products, such as 3-mA, 3-mG and 7-mG, whereas no significant activity was found towards deamination products, ethenoadducts or oxidation products. The efficiency of 3-mA and 3-mG removal was 5–10 times slower for Mag1 than for Escherichia coli AlkA whereas the rate of 7-mG removal was similar to the two enzymes. The relatively low efficiency for the removal of cytotoxic 3-methylpurines is consistent with the moderate sensitivity of the mag1 mutant to methylating agents. Furthermore, we studied the initial steps of Mag1-dependent base excision repair (BER) and genetic interactions with other repair pathways by mutant analysis. The double mutants mag1 nth1, mag1 apn2 and mag1 rad2 displayed increased resistance to methyl methanesulfonate (MMS) compared with the single mutants nth1, apn2 and rad2, respectively, indicating that Mag1 initiates both short-patch (Nth1-dependent) and long-patch (Rad2-dependent) BER of MMS-induced damage. Spontaneous intrachromosomal recombination frequencies increased 3-fold in the mag1 mutant suggesting that Mag1 and recombinational repair (RR) are both involved in repair of alkylated bases. Finally, we show that the deletion of mag1 in the background of rad16, nth1 and rad2 single mutants reduced the total recombination frequencies of all three double mutants, indicating that abasic sites formed as a result of Mag1 removal of spontaneous base lesions are substrates for nucleotide excision repair, long- and short-patch BER and RR

Visualising uncertainty: examining women's views on the role of Magnetic Resonance Imaging (MRI) in late pregnancy

Prenatal screening occupies a prominent role within sociological debates on medical uncertainty. A particular issue concerns the limitations of routine screening which tends to be based on risk prediction. Computer assisted visual technologies such as Magnetic Resonance Imaging (MRI) are now starting to be applied to the prenatal realm to assist in the diagnosis of a range of fetal and maternal disorders (from problems with the fetal brain to the placenta). MRI is often perceived in popular and medical discourse as a technology of certainty and truth. However, little is known about the use of MRI as a tool to confirm or refute the diagnosis of a range of disorders in pregnancy. Drawing on qualitative research with pregnant women attending a fetal medicine clinic in the North of England this paper examines the potential role that MRI can play in mediating pregnancy uncertainty. The paper will argue that MRI can create and manage women's feelings of uncertainty during pregnancy. However, while MRI may not always provide women with unequivocal answers, the detailed information provided by MR images combined with the interpretation and communication skills of the radiologist in many ways enables women to navigate the issue. Our analysis of empirical data therefore highlights the value of this novel technological application for women and their partners. It also seeks to stress the merit of taking a productive approach to the study of diagnostic uncertainty, an approach which recognises the concepts dual nature

Biometric analysis of the foetal meconium pattern using T1 weighted 2D gradient echo MRI

OBJECTIVES: Foetal MRI is used to assess abnormalities after ultrasonography. Bowel anomalies are a significant cause of neonatal morbidity, however there are little data concerning its normal appearance on antenatal MRI. This study aims to investigate the pattern of meconium accumulation throughout gestation using its hyperintense appearance on T1 weighted scans and add to the current published data. METHODS: This was a retrospective cohort study in a tertiary referral clinical MRI centre. Foetal body MRI scans of varying gestational ages were obtained dating between October 2011 and March 2018. The bowel was visualised on T1 weighted images. The length of the meconium and the width of the meconium at the rectum, sigmoid colon, splenic flexure and hepatic flexure was measured. Presence or absence of meconium in the small bowel was noted. Inter- and intrarater reliability was assessed. RESULTS: 181 foetal body scans were reviewed. 52 were excluded and 129 analysed. Visualisation of the meconium in the large bowel became increasingly proximal with later gestations, and small bowel visualisation was greater at earlier gestations. There was statistically significant strong (r = 0.6–0.8) or very strong (r = 0.8–1.0) positive correlation of length and width with increasing gestation. Interrater reliability was moderate to excellent (r = 0.4–1.0). CONCLUSION: This study provides new information regarding the pattern of meconium accumulation throughout gestation. With care, the results can be used in clinical practice to aid diagnosis of bowel pathology. ADVANCES IN KNOWLEDGE: The findings of this study provide further information concerning the normal accumulation of foetal meconium on MR imaging, an area where current research is limited