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"McIntosh, Craig"
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Effect of a cash transfer programme for schooling on prevalence of HIV and herpes simplex type 2 in Malawi: a cluster randomised trial
2012
Lack of education and an economic dependence on men are often suggested as important risk factors for HIV infection in women. We assessed the efficacy of a cash transfer programme to reduce the risk of sexually transmitted infections in young women.
In this cluster randomised trial, never-married women aged 13–22 years were recruited from 176 enumeration areas in the Zomba district of Malawi and randomly assigned with computer-generated random numbers by enumeration area (1:1) to receive cash payments (intervention group) or nothing (control group). Intervention enumeration areas were further randomly assigned with computer-generated random numbers to conditional (school attendance required to receive payment) and unconditional (no requirements to receive payment) groups. Participants in both intervention groups were randomly assigned by a lottery to receive monthly payments ranging from US$1 to $5, while their parents were independently assigned with computer-generated random numbers to receive $4–10. Behavioural risk assessments were done at baseline and 12 months; serology was tested at 18 months. Participants were not masked to treatment status but counsellors doing the serologic testing were. The primary outcomes were prevalence of HIV and herpes simplex virus 2 (HSV-2) at 18 months and were assessed by intention-to-treat analyses. The trial is registered, number NCT01333826.
88 enumeration areas were assigned to receive the intervention and 88 as controls. For the 1289 individuals enrolled in school at baseline with complete interview and biomarker data, weighted HIV prevalence at 18 month follow-up was 1·2% (seven of 490 participants) in the combined intervention group versus 3·0% (17 of 799 participants) in the control group (adjusted odds ratio [OR] 0·36, 95% CI 0·14–0·91); weighted HSV-2 prevalence was 0·7% (five of 488 participants) versus 3·0% (27 of 796 participants; adjusted OR 0·24, 0·09–0·65). In the intervention group, we noted no difference between conditional versus unconditional intervention groups for weighted HIV prevalence (3/235 [1%] vs 4/255 [2%]) or weighted HSV-2 prevalence (4/233 [1%] vs 1/255 [<1%]). For individuals who had already dropped out of school at baseline, we detected no significant difference between intervention and control groups for weighted HIV prevalence (23/210 [10%] vs 17/207 [8%]) or weighted HSV-2 prevalence (17/211 [8%] vs 17/208 [8%]).
Cash transfer programmes can reduce HIV and HSV-2 infections in adolescent schoolgirls in low-income settings. Structural interventions that do not directly target sexual behaviour change can be important components of HIV prevention strategies.
Global Development Network, Bill & Melinda Gates Foundation, National Bureau of Economic Research Africa Project, World Bank's Research Support Budget, and several World Bank trust funds (Gender Action Plan, Knowledge for Change Program, and Spanish Impact Evaluation fund).
Journal Article
FAIR TRADE AND FREE ENTRY: CAN A DISEQUILIBRIUM MARKET SERVE AS A DEVELOPMENT TOOL?
by
McIntosh, Craig
,
de Janvry, Alain
,
Sadoulet, Elisabeth
in
1997-2009
,
Certification
,
Charities
2015
The Fair Trade (FT) coffee initiative attempts to channel charity from consumers to poor producers via increased prices. We show that the rules of the FT system permit this rent to be eliminated due to free entry and costly excess certification of output. Using data from an association of coffee cooperatives in Central America, we verify that expected producer benefits are close to 0 when we take into account the output that is certified but not sold as FT. Our results illustrate how free entry undermines the attempt at extending charity via a price distortion in an otherwise competitive market.
Journal Article
Down syndrome and DYRK1A overexpression: relationships and future therapeutic directions
by
Wilton, Steve D.
,
Murphy, Aidan J.
,
Aung-Htut, May T.
in
antisense oligonucleotide
,
down syndrome
,
DSCR
2024
Down syndrome is a genetic-based disorder that results from the triplication of chromosome 21, leading to an overexpression of many triplicated genes, including the gene encoding Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase 1A (DYRK1A). This protein has been observed to regulate numerous cellular processes, including cell proliferation, cell functioning, differentiation, and apoptosis. Consequently, an overexpression of DYRK1A has been reported to result in cognitive impairment, a key phenotype of individuals with Down syndrome. Therefore, downregulating DYRK1A has been explored as a potential therapeutic strategy for Down syndrome, with promising results observed from in vivo mouse models and human clinical trials that administered epigallocatechin gallate. Current DYRK1A inhibitors target the protein function directly, which tends to exhibit low specificity and selectivity, making them unfeasible for clinical or research purposes. On the other hand, antisense oligonucleotides (ASOs) offer a more selective therapeutic strategy to downregulate DYRK1A expression at the gene transcript level. Advances in ASO research have led to the discovery of numerous chemical modifications that increase ASO potency, specificity, and stability. Recently, several ASOs have been approved by the U.S. Food and Drug Administration to address neuromuscular and neurological conditions, laying the foundation for future ASO therapeutics. The limitations of ASOs, including their high production cost and difficulty delivering to target tissues can be overcome by further advances in ASO design. DYRK1A targeted ASOs could be a viable therapeutic approach to improve the quality of life for individuals with Down syndrome and their families.
Journal Article
Induced alternative splicing an opportunity to study PCSK9 protein isoforms at physiologically relevant concentrations
2023
Splice modulating antisense oligomers (AOs) are increasingly used to modulate RNA processing. While most are investigated for their use as therapeutics, AOs can also be used for basic research. This study examined their use to investigate internally and terminally truncated proprotein convertase subtilisin/kexin type 9 (PCSK9) protein isoforms. Previous studies have used plasmid or viral-vector-mediated protein overexpression to study different PCSK9 protein isoforms, creating an artificial environment within the cell. Here we designed and tested AOs to remove specific exons that encode for PCSK9 protein domains and produced protein isoforms at more physiologically relevant levels. We evaluated the isoforms’ expression, secretion, and subsequent impact on the low-density lipoprotein (LDL) receptor and its activity in Huh-7 cells. We found that modifying the Cis-His-rich domain by targeting exons 10 or 11 negatively affected LDL receptor activity and hence did not enhance LDL uptake although the levels of LDL receptor were increased. On the other hand, removing the hinge region encoded by exon 8, or a portion of the prodomain encoded by exon 2, have the potential as therapeutics for hypercholesterolemia. Our findings expand the understanding of PCSK9 isoforms and their impact on the LDL receptor and its activity at physiologically relevant concentrations.
Journal Article
Estimating Treatment Effects from Spatial Policy Experiments: An Application to Ugandan Microfinance
2008
This paper demonstrates a method for estimating treatment effects in spatial tests, utilizing a second control group to measure unexplained spatial phenomena. The technique is implemented on two innovations in Ugandan microfinance, and we measure the ways in which concurrent shocks such as an Ebola outbreak and a contentious presidential election altered outcomes differentially across regions. By correcting for this spatial heterogeneity, we measure the impact of the policies; a program that increased borrowers' control over the terms of their loans improved outcomes, while the results of a program that bundled health insurance into the lending contract were more mixed.
Journal Article
Systematic Approach to Developing Splice Modulating Antisense Oligonucleotides
by
Greer, Kane
,
Aung-Htut, May
,
Ham, Kristin
in
Alternative Splicing - drug effects
,
Animals
,
Annealing
2019
The process of pre-mRNA splicing is a common and fundamental step in the expression of most human genes. Alternative splicing, whereby different splice motifs and sites are recognised in a developmental and/or tissue-specific manner, contributes to genetic plasticity and diversity of gene expression. Redirecting pre-mRNA processing of various genes has now been validated as a viable clinical therapeutic strategy, providing treatments for Duchenne muscular dystrophy (inducing specific exon skipping) and spinal muscular atrophy (promoting exon retention). We have designed and evaluated over 5000 different antisense oligonucleotides to alter splicing of a variety of pre-mRNAs, from the longest known human pre-mRNA to shorter, exon-dense primary gene transcripts. Here, we present our guidelines for designing, evaluating and optimising splice switching antisense oligomers in vitro. These systematic approaches assess several critical factors such as the selection of target splicing motifs, choice of cells, various delivery reagents and crucial aspects of validating assays for the screening of antisense oligonucleotides composed of 2′-O-methyl modified bases on a phosphorothioate backbone.
Journal Article
Induction of cryptic pre-mRNA splice-switching by antisense oligonucleotides
by
Wilton, Steve D.
,
Greer, Kane
,
Ham, Kristin A.
in
631/208/1792
,
631/337
,
Antisense oligonucleotides
2021
Antisense oligomers (AOs) are increasingly being used to modulate RNA splicing in live cells, both for research and for the development of therapeutics. While the most common intended effect of these AOs is to induce skipping of whole exons, rare examples are emerging of AOs that induce skipping of only part of an exon, through activation of an internal cryptic splice site. In this report, we examined seven AO-induced cryptic splice sites in six genes. Five of these cryptic splice sites were discovered through our own experiments, and two originated from other published reports. We modelled the predicted effects of AO binding on the secondary structure of each of the RNA targets, and how these alterations would in turn affect the accessibility of the RNA to splice factors. We observed that a common predicted effect of AO binding was disruption of the exon definition signal within the exon’s excluded segment.
Journal Article
In Vitro Validation of Phosphorodiamidate Morpholino Oligomers
by
Wilton, Steve D.
,
Fletcher, Sue
,
Aung-Htut, May T.
in
Animals
,
antisense oligonucleotide
,
Apoptosis
2019
One of the crucial aspects of screening antisense oligonucleotides destined for therapeutic application is confidence that the antisense oligomer is delivered efficiently into cultured cells. Efficient delivery is particularly vital for antisense phosphorodiamidate morpholino oligomers, which have a neutral backbone, and are known to show poor gymnotic uptake. Here, we report several methods to deliver these oligomers into cultured cells. Although 4D-Nucleofector™ or Neon™ electroporation systems provide efficient delivery and use lower amounts of phosphorodiamidate morpholino oligomer, both systems are costly. We show that some readily available transfection reagents can be used to deliver phosphorodiamidate morpholino oligomers as efficiently as the electroporation systems. Among the transfection reagents tested, we recommend Lipofectamine 3000™ for delivering phosphorodiamidate morpholino oligomers into fibroblasts and Lipofectamine 3000™ or Lipofectamine 2000™ for myoblasts/myotubes. We also provide optimal programs for nucleofection into various cell lines using the P3 Primary Cell 4D-Nucleofector™ X Kit (Lonza), as well as antisense oligomers that redirect expression of ubiquitously expressed genes that may be used as positive treatments for human and murine cell transfections.
Journal Article
Economic vulnerability, violence, and sexual risk factors for HIV among female sex workers in Tijuana, Mexico
2022
Economic vulnerability is often reported to underlie involvement in sex work among female sex workers (FSW), but may also create urgency in women’s work, limiting women’s negotiating power with clients and in turn, increasing their vulnerability for violence and HIV. This study assessed economic vulnerability in relation to violence and sexual risk behaviors for HIV among a sample of FSW in Tijuana, Mexico. FSW at least 18 years of age were recruited through venue-based sampling for a survey (n = 228) and in-depth interviews (n = 50) to investigate HIV risk factors in this region. Using crude and adjusted logistic regression models, we assessed lack of financial support from others as well as reports of financial hardship separately in relation to experiencing sexual violence (e.g. by clients, police, relationship partners, in the past 6 months), physical violence (past 6 months), STI diagnosis, and inconsistent condom use (past 30 days). Qualitative interviews (n = 50), conducted with a subsample of the survey participants, were also examined for related themes. FSW who reported no financial support were more likely to report sexual violence (OR = 2.1; 95% CI:1.1–4.2). FSW who reported financial hardship were more likely to experience sexual violence (OR = 1.9; 95% CI:1.1–3.6) and physical violence (OR = 1.9; 95% CI:1.1–3.6), as well as to report past 30-day inconsistent condom use (OR = 2.4; 95%CI: 1.3–4.6) and to test positive for an STI (OR = 1.9; 95% CI:1.1–3.4). Qualitative data substantiated these findings. Findings suggest that interventions to improve economic well-being may be useful to prevent the intersecting concerns of violence and HIV among FSW.
Journal Article
Removal of the Polyglutamine Repeat of Ataxin-3 by Redirecting pre-mRNA Processing
2019
Spinocerebellar ataxia type 3 (SCA3) is a devastating neurodegenerative disease for which there is currently no cure, nor effective treatment strategy. One of nine polyglutamine disorders known to date, SCA3 is clinically heterogeneous and the main feature is progressive ataxia, which in turn affects speech, balance and gait of the affected individual. SCA3 is caused by an expanded polyglutamine tract in the ataxin-3 protein, resulting in conformational changes that lead to toxic gain of function. The expanded glutamine tract is located at the 5′ end of the penultimate exon (exon 10) of ATXN3 gene transcript. Other studies reported removal of the expanded glutamine tract using splice switching antisense oligonucleotides. Here, we describe improved efficiency in the removal of the toxic polyglutamine tract of ataxin-3 in vitro using phosphorodiamidate morpholino oligomers, when compared to antisense oligonucleotides composed of 2′-O-methyl modified bases on a phosphorothioate backbone. Significant downregulation of both the expanded and non-expanded protein was induced by the morpholino antisense oligomer, with a greater proportion of ataxin-3 protein missing the polyglutamine tract. With growing concerns over toxicity associated with long-term administration of phosphorothioate oligonucleotides, the use of a phosphorodiamidate morpholino oligomer may be preferable for clinical application. These results suggest that morpholino oligomers may provide greater therapeutic benefit for the treatment of spinocerebellar ataxia type 3, without toxic effects.
Journal Article