22 research outputs found

    ‘I arranged my own marriage': arranged marriages and post-colonial feminism

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    This article looks at the practice of arranged marriage among women of Indian, Pakistani and Bangladeshi origin resident in Britain. It examines the conflation of arranged marriages with forced marriages and the assumption that arranged marriages are examples of cultural practices that thwart individual agency. Drawing upon original empirical data, this article will argue that in the practice of arranged marriage, some South Asian women are able to exercise agency while choosing their marriage partner. They adapt traditional arranged marriage practices to navigate their way around strict cultural expectations and to negotiate with their family members the choice of a match that is favourable for them. It provides a corrective account of arranged marriages by challenging the stereotype of the ‘oppressed third world women' and their experiences of such marriages. The article will do this by employing the idea of post-colonial feminism and by highlighting two long-standing issues in feminist debates: the idea of agency and the conception and role of power in the struggle for women's rights. It will make a case for a post-colonial approach to feminism as one way of reconciling feminism with the politics of multiculturalism

    Cognitive Training and Transcranial Direct Current Stimulation in Mild Cognitive Impairment: A Randomized Pilot Trial

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    BackgroundTranscranial direct current stimulation (tDCS), a non-invasive stimulation, represents a potential intervention to enhance cognition across clinical populations including Alzheimer’s disease and mild cognitive impairment (MCI). This randomized clinical trial in MCI investigated the effects of anodal tDCS (a-tDCS) delivered to left inferior frontal gyrus (IFG) combined with gist-reasoning training (SMART) versus sham tDCS (s-tDCS) plus SMART on measures of cognitive and neural changes in resting cerebral blood flow (rCBF). We were also interested in SMART effects on cognitive performance regardless of the tDCS group.MethodsTwenty-two MCI participants, who completed the baseline cognitive assessment (T1), were randomized into one of two groups: a-tDCS + SMART and s-tDCS + SMART. Of which, 20 participants completed resting pCASL MRI scan to measure rCBF. Eight SMART sessions were administered over 4 weeks with a-tDCS or s-tDCS stimulation for 20 min before each session. Participants were assessed immediately (T2) and 3-months after training (T3).ResultsSignificant group × time interactions showed cognitive gains at T2 in executive function (EF) measure of inhibition [DKEFS- Color word (p = 0.047)], innovation [TOSL (p = 0.01)] and on episodic memory [TOSL (p = 0.048)] in s-tDCS + SMART but not in a-tDCS + SMART group. Nonetheless, the gains did not persist for 3 months (T3) after the training. A voxel-based analysis showed significant increase in regional rCBF in the right middle frontal cortex (MFC) (cluster-wise p = 0.05, k = 1,168 mm3) in a-tDCS + SMART compared to s-tDCS + SMART. No significant relationship was observed between the increased CBF with cognition. Irrespective of group, the combined MCI showed gains at T2 in EF of conceptual reasoning [DKEFS card sort (p = 0.033)] and category fluency [COWAT (p = 0.055)], along with gains at T3 in EF of verbal fluency [COWAT (p = 0.009)].ConclusionOne intriguing finding is a-tDCS to left IFG plus SMART increased blood flow to right MFC, however, the stimulation seemingly blocked cognitive benefits of SMART on EF (inhibition and innovation) and episodic memory compared to s-tDCS + SMART group. Although the sample size is small, this paper contributes to growing evidence that cognitive training provides a way to significantly enhance cognitive performance in adults showing memory loss, where the role of a-tDCS in augmenting these effects need further study

    Generation of SARS-CoV-2 escape mutations by monoclonal antibody therapy

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    COVID-19 patients at risk of severe disease may be treated with neutralising monoclonal antibodies (mAbs). To minimise virus escape from neutralisation these are administered as combinations e.g. casirivimab+imdevimab or, for antibodies targeting relatively conserved regions, individually e.g. sotrovimab. Unprecedented genomic surveillance of SARS-CoV-2 in the UK has enabled a genome-first approach to detect emerging drug resistance in Delta and Omicron cases treated with casirivimab+imdevimab and sotrovimab respectively. Mutations occur within the antibody epitopes and for casirivimab+imdevimab multiple mutations are present on contiguous raw reads, simultaneously affecting both components. Using surface plasmon resonance and pseudoviral neutralisation assays we demonstrate these mutations reduce or completely abrogate antibody affinity and neutralising activity, suggesting they are driven by immune evasion. In addition, we show that some mutations also reduce the neutralising activity of vaccine-induced serum

    The SARS-CoV-2 neutralizing antibody response to SD1 and its evasion by BA.2.86

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    Under pressure from neutralising antibodies induced by vaccination or infection the SARS-CoV-2 spike gene has become a hotspot for evolutionary change, leading to the failure of all mAbs developed for clinical use. Most potent antibodies bind to the receptor binding domain which has become heavily mutated. Here we study responses to a conserved epitope in sub-domain-1 (SD1) of spike which have become more prominent because of mutational escape from antibodies directed to the receptor binding domain. Some SD1 reactive mAbs show potent and broad neutralization of SARS-CoV-2 variants. We structurally map the dominant SD1 epitope and provide a mechanism of action by blocking interaction with ACE2. Mutations in SD1 have not been sustained to date, but one, E554K, leads to escape from mAbs. This mutation has now emerged in several sublineages including BA.2.86, reflecting selection pressure on the virus exerted by the increasing prominence of the anti-SD1 response

    Emerging variants develop total escape from potent monoclonal antibodies induced by BA.4/5 infection

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    The rapid evolution of SARS-CoV-2 is driven in part by a need to evade the antibody response in the face of high levels of immunity. Here, we isolate spike (S) binding monoclonal antibodies (mAbs) from vaccinees who suffered vaccine break-through infections with Omicron sub lineages BA.4 or BA.5. Twenty eight potent antibodies are isolated and characterised functionally, and in some cases structurally. Since the emergence of BA.4/5, SARS-CoV-2 has continued to accrue mutations in the S protein, to understand this we characterize neutralization of a large panel of variants and demonstrate a steady attrition of neutralization by the panel of BA.4/5 mAbs culminating in total loss of function with recent XBB.1.5.70 variants containing the so-called ‘FLip’ mutations at positions 455 and 456. Interestingly, activity of some mAbs is regained on the recently reported variant BA.2.86

    A structure-function analysis shows SARS-CoV-2 BA.2.86 balances antibody escape and ACE2 affinity.

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    BA.2.86, a recently described sublineage of SARS-CoV-2 Omicron, contains many mutations in the spike gene. It appears to have originated from BA.2 and is distinct from the XBB variants responsible for many infections in 2023. The global spread and plethora of mutations in BA.2.86 has caused concern that it may possess greater immune-evasive potential, leading to a new wave of infection. Here, we examine the ability of BA.2.86 to evade the antibody response to infection using a panel of vaccinated or naturally infected sera and find that it shows marginally less immune evasion than XBB.1.5. We locate BA.2.86 in the antigenic landscape of recent variants and look at its ability to escape panels of potent monoclonal antibodies generated against contemporary SARS-CoV-2 infections. We demonstrate, and provide a structural explanation for, increased affinity of BA.2.86 to ACE2, which may increase transmissibility

    A delicate balance between antibody evasion and ACE2 affinity for Omicron BA.2.75

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    Variants of SARS CoV-2 have caused successive global waves of infection. These variants, with multiple mutations in the spike protein are thought to facilitate escape from natural and vaccine-induced immunity and often increase in the affinity for ACE2. The latest variant to cause concern is BA.2.75, identified in India where it is now the dominant strain, with evidence of wider dissemination. BA.2.75 is derived from BA.2 and contains four additional mutations in the receptor binding domain (RBD). Here we perform an antigenic and biophysical characterization of BA.2.75, revealing an interesting balance between humoral evasion and ACE2 receptor affinity. ACE2 affinity for BA.2.75 is increased 9-fold compared to BA.2; there is also evidence of escape of BA.2.75 from immune serum, particularly that induced by Delta infection which may explain the rapid spread in India, where BA.2.75 is now the dominant variant. ACE2 affinity appears to be prioritised over greater escape

    Antibody escape of SARS-CoV-2 Omicron BA.4 and BA.5 from vaccine and BA.1 serum

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    The Omicron lineage of SARS-CoV-2, first described in November 2021, spread rapidly to become globally dominant and has split into a number of sub-lineages. BA.1 dominated the initial wave but has been replaced by BA.2 in many countries. Recent sequencing from South Africa’s Gauteng region uncovered two new sub-lineages, BA.4 and BA.5 which are taking over locally, driving a new wave. BA.4 and BA.5 contain identical spike sequences and, although closely related to BA.2, contain further mutations in the receptor binding domain of spike. Here, we study the neutralization of BA.4/5 using a range of vaccine and naturally immune serum and panels of monoclonal antibodies. BA.4/5 shows reduced neutralization by serum from triple AstraZeneca or Pfizer vaccinated individuals compared to BA.1 and BA.2. Furthermore, using serum from BA.1 vaccine breakthrough infections there are likewise, significant reductions in the neutralization of BA.4/5, raising the possibility of repeat Omicron infections

    Prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with cytologically negative Pap smear

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    Objective: To study the prevalence of high-risk human papillomavirus (HR-HPV) types 16 and 18 in healthy women with negative Pap smears in identifying women with underlying cervical squamous intra-epithelial (SIL) lesions. Methods: A total of 3300 women who were attending the Gynecology OPD of Lok Nayak Hospital, one of the major government tertiary hospitals in New Delhi, were screened during a 1-year study period, and 2079 (63%) of them were found to have cytologically negative Pap smear with inflammation and the rest (37%) also had negative Pap report but without inflammation. Hundred and sixty of these sexually active women aged between 20 and 60 years were randomly selected, and were investigated by colposcopy and a guided biopsy was done wherever required. HPV types 16 and 18 DNA was detected in scraped cervical cells from all women using type-specific primers in polymerase chain reaction (PCR). Results: The high-risk HPV (type 16 and 18) prevalence by PCR was found to be 10% (16/160). Histopathological findings were obtained in 123 women, out of which 15 had LSIL and four had HSIL. High-risk HPV types 16/18 could be detected in nine out of these 19 (47.3%) squamous intra-epithelial lesions (p<0.00008) which includes two out of the four women (50%) having HSIL, while only seven out of 104 (6.7%) of the subjects with normal (negative) Pap reports (p=0.03) had infection of high-risk HPV. Conclusion: The results indicate that about 10% of women who show a negative Pap smear, but have inflammation are positive for high-risk HPV types 16/18 and about 15% harbor squamous intra-epithelial lesions. It is suggested that high-risk HPV detection can be utilized as an adjunct to routine cytology screening programs to identify 'high risk' women who have concurrently negative Pap smears but may harbor oncogenic HPV infection and/or more likely to develop CIN lesions

    Glycosylation of the core of the HIV-1 envelope subunit protein gp120 is not required for native trimer formation or viral infectivity

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    The gp120 subunit of the HIV-1 envelope (Env) protein is heavily glycosylated at similar to 25 glycosylation sites, of which similar to 7-8 are located in the V1/V2 and V3 variable loops and the others in the remaining core gp120 region. Glycans partially shield Env from recognition by the host immune system and also are believed to be indispensable for proper folding of gp120 and for viral infectivity. Previous attempts to alter glycosylation sites in Env typically involved mutating the glycosylated asparagine residues to structurally similar glutamines or alanines. Here, we confirmed that such mutations at multiple glycosylation sites greatly diminish viral infectivity and result in significantly reduced binding to both neutralizing and non-neutralizing antibodies. Therefore, using an alternative approach, we combined evolutionary information with structure-guided design and yeast surface display to produce properly cleaved HIV-1 Env variants that lack all 15 core gp120 glycans, yet retain conformational integrity and multiple-cycle viral infectivity and bind to several broadly neutralizing antibodies (bNAbs), including trimer-specific antibodies and a germline-reverted version of the bNAb VRC01. Our observations demonstrate that core gp120 glycans are not essential for folding, and hence their likely primary role is enabling immune evasion. We also show that our glycan removal approach is not strain restricted. Glycan-deficient Env derivatives can be used as priming immunogens because they should engage and activate a more divergent set of germlines than fully glycosylated Env. In conclusion, these results clarify the role of core gp120 glycosylation and illustrate a general method for designing glycan-free folded protein derivatives
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