83 research outputs found

    An introduction to the written works of Nawal al-Sa'dawi.

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    Nawal al-Sa'dawi is an Egyptian doctor and feminist writer whose sociological works have had a great impact on her society and the Arab world. This thesis sets out to trace how Sa'dawi's work as a doctor during the 1960s brought her into such close contact with the sufferings of women and girls in her society, that she set out to try and discover the reasons for such widespread oppression of her own sex. Each of Sa'dawi's factual works is treated separately here in chronological order. These works show Sa'dawi protesting against sexual and social abuses of women, against female circumcision and double standards of morality in her society. When she tries to expose the root causes of Arab women's oppression, she points the finger of blame at patriarchal society, economic pressures and misguided interpretations of psychology and religion. Sa'dawi is prevented from speaking out frankly against political or religious institutions because of the threat of censorship which carries with it the danger of imprisonment and persecution. Apart from a critical examination of her factual books, this thesis also contains a survey of her fictional works, for Sa'dawi has also achieved success in the field of literature with her short stories and novels. Her fiction frequently brings to the reader typical dilemmas facing women in Egyptian society. Again each work is discussed individually here. Since Sa'dawi is still very active as a writer, I have had to confine my thesis to covering her output up to 1986, which means that nineteen works are discussed in detail. The tremendous popularity of Sa'dawi and her written works rests largely on her commitment to helping her compatriots achieve balanced healthy lives from the psychological, physical and sexual dimensions, through frank discussions of highly controversial subjects. During the 1980s, Sa'dawi's fame has spread to the West where she is rightly regarded as the leading spokeswoman for Arab feminism

    Application of fluorescence correlation spectroscopy to study substrate binding in styrene maleic acid lipid copolymer encapsulated ABCG2

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    © 2020 The Authors ABCG2 is one of a trio of human ATP binding cassette transporters that have the ability to bind and transport a diverse array of chemical substrates out of cells. This so-called “multidrug” transport has numerous physiological consequences including effects on how drugs are absorbed into and eliminated from the body. Understanding how ABCG2 is able to interact with multiple drug substrates remains an important goal in transporter biology. Most drugs are believed to interact with ABCG2 through the hydrophobic lipid bilayer and experimental systems for ABCG2 study need to incorporate this. We have exploited styrene maleic acid to solubilise ABCG2 from HEK293T cells overexpressing the transporter, and confirmed by dynamic light scattering and fluorescence correlation spectroscopy (FCS) that this results in the extraction of SMA lipid copolymer (SMALP) particles that are uniform in size and contain a dimer of ABCG2, which is the predominant physiological state. FCS was further employed to measure the diffusion of a fluorescent ABCG2 substrate (BODIPY-prazosin) in the presence and absence of SMALP particles of purified ABCG2. Autocorrelation analysis of FCS traces enabled the mathematical separation of free BODIPY-prazosin from drug bound to ABCG2 and allowed us to show that combining SMALP extraction with FCS can be used to study specific drug: transporter interactions

    Residues contributing to drug transport by ABCG2 are localised to multiple drug-binding pockets

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    Multidrug binding and transport by the ATP binding cassette transporter ABCG2 is a factor in the clinical resistance to chemotherapy in leukaemia, and a contributory factor to the pharmacokinetic profiles of many other prescribed drugs. Despite its importance, the structural basis of multidrug transport, i.e. the ability to transport multiple distinct chemicals, has remained elusive. Previous research has shown that at least two residues positioned towards the cytoplasmic end of transmembrane helix 3 (TM3) of the transporter play a role in drug transport. We hypothesised that other residues, either in the longitudinal span of TM3, or a perpendicular slice through the intracellular end of other TM helices would also contribute to drug binding and transport by ABCG2. Single point mutant isoforms of ABCG2 were made at approximately 30 positions and were analysed for effects on protein expression, localisation (western blotting, confocal microscopy) and function (flow cytometry) in a mammalian stable cell line expression system. Our data were interpreted in terms of recent structural data on the ABCG protein subfamily and enabled us to propose a surface binding site for the drug mitoxantrone as well as a second, buried site for the same drug. Further mutational analysis of residues that spatially separate these two sites prompt us to suggest a molecular and structural pathway for mitoxantrone binding by ABCG2

    Clinically relevant mutations in the ABCG2 transporter uncovered by genetic analysis linked to erythrocyte membrane protein expression

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    The ABCG2 membrane protein is a key xeno- and endobiotic transporter, modulating the absorption and metabolism of pharmacological agents and causing multidrug resistance in cancer. ABCG2 is also involved in uric acid elimination and its impaired function is causative in gout. Analysis of ABCG2 expression in the erythrocyte membranes of healthy volunteers and gout patients showed an enrichment of lower expression levels in the patients. By genetic screening based on protein expression, we found a relatively frequent, novel ABCG2 mutation (ABCG2-M71V), which, according to cellular expression studies, causes reduced protein expression, although with preserved transporter capability. Molecular dynamics simulations indicated a stumbled dynamics of the mutant protein, while ABCG2-M71V expression in vitro could be corrected by therapeutically relevant small molecules. These results suggest that personalized medicine should consider this newly discovered ABCG2 mutation, and genetic analysis linked to protein expression provides a new tool to uncover clinically important mutations in membrane proteins. © 2018 The Author(s)

    Delivering a multi-functional and resilient urban forest

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    Tree planting is widely advocated and applied in urban areas, with large-scaleprojects underway in cities globally. Numerous potential benefits are used to justify these planting campaigns. However, reports of poor tree survival raise questions about the ability of such projects to deliver on their promises over the long-term. Each potential benefit requires different supporting conditions—relating not only to the type and placement of the tree, but also to the broader urban system within which it is embedded. This set of supportingconditions may not always be mutually compatible and may not persist for the lifetime of the tree. Here, we demonstrate a systems-based approach that makes these dependencies, synergies, and tensions more explicit, allowing them to be used to test the decadal-scale resilience of urban street trees. Our analysis highlights social, environmental, and economic assumptions that are implicit within planting projects; notably that high levels of maintenance and public support for urban street trees will persist throughout their natural lifespan, andthat the surrounding built form will remain largely unchanged. Whilst the vulnerability of each benefit may be highly context specific, we identify approaches that address some typical weaknesses, making a functional, resilient, urban forest more attainable.

    The Essential Nucleolar Yeast Protein Nop8p Controls the Exosome Function during 60S Ribosomal Subunit Maturation

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    The yeast nucleolar protein Nop8p has previously been shown to interact with Nip7p and to be required for 60S ribosomal subunit formation. Although depletion of Nop8p in yeast cells leads to premature degradation of rRNAs, the biochemical mechanism responsible for this phenotype is still not known. In this work, we show that the Nop8p amino-terminal region mediates interaction with the 5.8S rRNA, while its carboxyl-terminal portion interacts with Nip7p and can partially complement the growth defect of the conditional mutant strain Δnop8/GAL::NOP8. Interestingly, Nop8p mediates association of Nip7p to pre-ribosomal particles. Nop8p also interacts with the exosome subunit Rrp6p and inhibits the complex activity in vitro, suggesting that the decrease in 60S ribosomal subunit levels detected upon depletion of Nop8p may result from degradation of pre-rRNAs by the exosome. These results strongly indicate that Nop8p may control the exosome function during pre-rRNA processing

    The Human Nucleolar Protein FTSJ3 Associates with NIP7 and Functions in Pre-rRNA Processing

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    NIP7 is one of the many trans-acting factors required for eukaryotic ribosome biogenesis, which interacts with nascent pre-ribosomal particles and dissociates as they complete maturation and are exported to the cytoplasm. By using conditional knockdown, we have shown previously that yeast Nip7p is required primarily for 60S subunit synthesis while human NIP7 is involved in the biogenesis of 40S subunit. This raised the possibility that human NIP7 interacts with a different set of proteins as compared to the yeast protein. By using the yeast two-hybrid system we identified FTSJ3, a putative ortholog of yeast Spb1p, as a human NIP7-interacting protein. A functional association between NIP7 and FTSJ3 is further supported by colocalization and coimmunoprecipitation analyses. Conditional knockdown revealed that depletion of FTSJ3 affects cell proliferation and causes pre-rRNA processing defects. The major pre-rRNA processing defect involves accumulation of the 34S pre-rRNA encompassing from site A′ to site 2b. Accumulation of this pre-rRNA indicates that processing of sites A0, 1 and 2 are slower in cells depleted of FTSJ3 and implicates FTSJ3 in the pathway leading to 18S rRNA maturation as observed previously for NIP7. The results presented in this work indicate a close functional interaction between NIP7 and FTSJ3 during pre-rRNA processing and show that FTSJ3 participates in ribosome synthesis in human cells

    Neoadjuvant Endocrine Therapy in Breast Cancer Upregulates the Cytotoxic Drug Pump ABCG2/BCRP, and May Lead to Resistance to Subsequent Chemotherapy

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    Introduction: Neoadjuvant treatments for primary breast cancer are becoming more common; however, little is known about how these impact on response to subsequent adjuvant therapies. Conveniently, neoadjuvant therapy provides opportunities to consider this question, by studying therapy-induced expression changes using comparisons between pre- and posttreatment samples. These data are relatively lacking in the context of neoadjuvant endocrine therapy, as opposed to the more common neoadjuvant chemotherapy. Here, we investigate the relevance of expression of the xenobiotic transporter ABCG2/BCRP, a gene/protein associated with chemoresistance, in the context of neoadjuvant endocrine therapy and particularly with reference to subsequent chemotherapy treatment. Materials and Methods: ABCG2/BCRP expression was assessed by immunohistochemistry or by expression arrays in matched patient samples pre- and post-neoadjuvant endocrine therapy. Cell culture was used to model the impact of endocrine therapy-induced changes in ABCG2/BCRP on subsequent chemotherapy response, using Western blots, quantitative polymerase chain reaction, survival assays, and cell cycle analyses. Results: ABCG2/BCRP was commonly and significantly upregulated in breast cancers after treatment with neoadjuvant endocrine therapy in 3 separate cohorts encompassing a total of 200 patients. Treatment with the endocrine therapeutic tamoxifen similarly induced ABCG2/BCRP upregulation in a relevant model cell line, the estrogen receptor-positive line T47D. Critically, this upregulation was associated with significantly increased chemoresistance to subsequent treatment with epirubicin, an anthracycline commonly used in breast cancer adjuvant chemotherapy. Conclusion: Our data suggest that neoadjuvant endocrine therapy may induce poor responses to adjuvant chemotherapy, and therefore, that clinical outcomes following this treatment sequence warrant further study

    The risky womb and the unthinkability of the pregnant man: addressing trans masculine hysterectomy

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    In April 2017, the European Court of Human Rights ruled that requiring trans people to undergo sterilisation in order to grant legal gender recognition was a breach of human rights. In the UK, sterilisation has never been a legal requirement for trans people. However, hysterectomy and salpingo-oopherectomy have been strongly encouraged for trans masculine people on medical grounds, although the clinical evidence for current recommendations is weak. Within this article I analyse the issue from a feminist perspective and argue that current presumptions in favour of surgical intervention are influenced by the history of medical interventions to “fix” bodies perceived as female, coupled with a strong social taboo against the pregnant man. As a consequence, medical and legal frameworks are not necessarily facilitating optimal outcomes for the individual. I suggest that practices in this regard should be critically examined, with a view to developing more tailored, person-centred practices and facilitating informed choice
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