The importance of Na(plus)-K(plus)-Cl- cotransport in nitrogen mustard induced cell death

The incubation of murine leukaemic L1210 cells in vitro for 4 hours (hr) with 10uM nitrogen mustard (HN2), a bifunctional alkylating agent, inhibited the influx of the potassium congener, 88rubidium+ ( 86Rb+) by the selective inhibition of the Na+-K+-CI- cotransporter. The aim of this project was to investigate the importance of this lesion in HN2-induced cytotoxicity. 86Rb+ uptake in human erythrocytes was inhibited by high concentrations of HN2 (2mM) and occurred in two phases.In the first hour both the Na+/K+ ATPase pump and the Na+-K+-CI- cotransporter were equally inhibited but after 2 hrs exposure to 2mM HN2, the Na+ -K+ -CI- cotransporter was significantly more inhibited than the Na+/K+ ATPase pump. In contrast, both potassium transport systems were equally inhibited in L1210 cells incubated for 10 minutes with 1mM HN2. The selective inhibition of the Na+-K+-CI- cotransporter, after a 3 hrs exposure to 10uM HN2, was not absolved by coincubation with 5ug/ml cycloheximide (CHX), an inhibitor of protein synthesis. Incubation of L1210 cells with concentrations of diuretics which completely inhibited Na+-K+-CI- cotransport did not enhance the cytotoxicity of either HN2 or its monofunctional analogue 2-chloroethyldimethylamine (Me-HN1). The incubation of L1210 cells with a twice strength Rosewell Park Memorial Institute 1640 media did not enhance the toxicity of HN2. An L1210 cell line (L1210FR) was prepared which was able to grow in toxic concentrations of furosemide and exhibited a similiar sensitivity to HN2 as parental L1210 cells. Treatment of L1210 cells with 10uM HN2 resulted in a decrease in cell volume which was concurrent with the inhibition of the Na+-K+-CI- cotransporter. This was not observed in L1210 cells treated with either 1 or O.SuM HN2. Thus, possible differences in the cell death, in terms of necrosis and apoptosis, induced by the different concentrations of HN2 was investigated. The cell cycle of L1210 cells appeared to be blocked non-specifically by 10uM HN2 and in S and G2/M by either 1 or 0.5uM HN2. There were no significant changes in the cytosolic calcium concentrations of L1210 cells for up to 48 hrs after exposure to the three concentrations of HN2. No protection against th_ toxic effects of HN2 was observed in L1210 cells incubated with 5ug/ml CHX for up to 6 hrs. Incubation for 12 or 18 hrs with a non-toxic concentration (5mM) of L-Azetidine-2- carboxylic acid (ACA) enhanced the toxicity of low concentrations (<0.5uM) of HN2

A pilot sentinel surveillance system to monitor treatment and treatment outcomes of chronic hepatitis B and C infections in clinical centres in three European countries, 2019

Hepatitis B; Hepatitis C; SurveillanceHepatitis B; Hepatitis C; VigilanciaHepatitis B; Hepatitis C; VigilànciaBackgroundThe World Health Organization European Action Plan 2020 targets for the elimination of viral hepatitis are that > 75% of eligible individuals with chronic hepatitis B (HBV) or hepatitis C (HCV) are treated, of whom > 90% achieve viral suppression.AimTo report the results from a pilot sentinel surveillance to monitor chronic HBV and HCV treatment uptake and outcomes in 2019.MethodsWe undertook retrospective enhanced data collection on patients with a confirmed chronic HBV or HCV infection presenting at one of seven clinics in three countries (Croatia, Romania and Spain) for the first time between 1 January 2019 and 30 June 2019. Clinical records were reviewed from date of first attendance to 31 December 2019 and data on sociodemographics, clinical history, laboratory results, treatment and treatment outcomes were collected. Treatment eligibility, uptake and case outcome were assessed.ResultsOf 229 individuals with chronic HBV infection, treatment status was reported for 203 (89%). Of the 80 individuals reported as eligible for treatment, 51% (41/80) were treated of whom 89% (33/37) had achieved viral suppression. Of 240 individuals with chronic HCV infection, treatment status was reported for 231 (96%). Of 231 eligible individuals, 77% (179/231) were treated, the majority of whom had received direct acting antivirals (99%, 174/176) and had achieved sustained virological response (98%, 165/169).ConclusionTreatment targets for global elimination were missed for HBV but not for HCV. A wider European implementation of sentinel surveillance with a representative sample of sites could help monitor progress towards achieving hepatitis control targets.The study was supported by the European Centre for Disease Prevention and Control (ECDC) as part of the contract “Sentinel surveillance of hepatitis B and C in the EU/EEA – feasibility, assessment, protocol development and pilot (NP/2019/OCS/10528)”

A qualitative assessment of the acceptability of hepatitis C remote self-testing and self-sampling amongst people who use drugs in London, UK.

BACKGROUND: Hepatitis C (HCV) diagnosis and care is a major challenge for people who use illicit drugs, and is characterised by low rates of testing and treatment engagement globally. New approaches to fostering engagement are needed. We explored the acceptability of remote forms of HCV testing including self-testing and self-sampling among people who use drugs in London, UK. METHODS: A qualitative rapid assessment was undertaken with people who use drugs and stakeholders in London, UK. Focus groups were held with men who have sex with men engaged in drug use, people who currently inject drugs and people who formerly injected drugs (22 participants across the 3 focus groups). Stakeholders participated in semi-structured interviews (n = 5). We used a thematic analysis to report significant themes in participants' responses. RESULTS: We report an overarching theme of 'tension' in how participants responded to the acceptability of remote testing. This tension is evident across four separate sub-themes we explore. First, choice and control, with some valuing the autonomy and privacy remote testing could support. Second, the ease of use of self testing linked to its immediate result and saliva sample was preferred over the delayed result from a self administered blood sample tested in a laboratory. Third, many respondents described the need to embed remote testing within a supportive care pathway. Fourth, were concerns over managing a positive result, and its different meanings, in isolation. CONCLUSIONS: The concept of remote HCV testing is acceptable to some people who use drugs in London, although tensions with lived experience of drug use and health system access limit its relevance. Future development of remote testing must respond to concerns raised in order for acceptable implementation to take place

Associations between historical residential redlining and current age-adjusted rates of emergency department visits due to asthma across eight cities in California: an ecological study.

BackgroundAsthma disproportionately affects communities of colour in the USA, but the underlying factors for this remain poorly understood. In this study, we assess the role of historical redlining as outlined in security maps created by the Home Owners' Loan Corporation (HOLC), the discriminatory practice of categorising neighbourhoods on the basis of perceived mortgage investment risk, on the burden of asthma in these neighbourhoods.MethodsWe did an ecological study of HOLC risk grades and asthma exacerbations in California using the security maps available for the following eight cities: Fresno, Los Angeles, Oakland, Sacramento, San Diego, San Jose, San Francisco, and Stockton. Each census tract was categorised into one of four risk levels (A, B, C, or D) on the basis of the location of population-weighted centroids on security maps, with the worst risk level (D) indicating historical redlining. We obtained census tract-level rates of emergency department visits due to asthma from CalEnviroScreen 3.0. We assessed the relationship between risk grade and log-transformed asthma visit rates between 2011 and 2013 using ordinary least squares regression. We included potential confounding variables from the 2010 Census and CalEnviroScreen 3.0: diesel exhaust particle emissions, PM2·5, and percent of the population living below 2 times the federal poverty level. We also built random intercept and slope models to assess city-level variation in the relationship between redlining and asthma.FindingsIn the 1431 census tracts assessed (64 [4·5%] grade A, 241 [16·8%] grade B, 719 [50·2%] grade C, and 407 [28·4%] grade D), the proportion of the population that was non-Hispanic black and Hispanic, the percentage of the population living in poverty, and diesel exhaust particle emissions all significantly increased as security map risk grade worsened (p&lt;0·0001). The median age-adjusted rates of emergency department visits due to asthma were 2·4 times higher in census tracts that were previously redlined (median 63·5 [IQR 34·3] visits per 10 000 residents per year [2011-13]) than in tracts at the lowest risk level (26·5 [18·4]). In adjusted models, redlined census tracts were associated with a relative risk of 1·39 (95% CI 1·21-1·57) in rates of emergency department visits due to asthma compared with that of lowest-risk census tracts.InterpretationHistorically redlined census tracts have significantly higher rates of emergency department visits due to asthma, suggesting that this discriminatory practice might be contributing to racial and ethnic asthma health disparities.FundingNational Heart Lung Blood Institute

Economic evaluation of HIV pre-exposure prophylaxis among men-who-have-sex-with-men in England in 2016.

Clinical effectiveness of pre-exposure prophylaxis (PrEP) for preventing HIV acquisition in men who have sex with men (MSM) at high HIV risk is established. A static decision analytical model was constructed to inform policy prioritisation in England around cost-effectiveness and budgetary impact of a PrEP programme covering 5,000 MSM during an initial high-risk period. National genitourinary medicine clinic surveillance data informed key HIV risk assumptions. Pragmatic large-scale implementation scenarios were explored. At 86% effectiveness, PrEP given to 5,000 MSM at 3.3 per 100 person-years annual HIV incidence, assuming risk compensation (20% HIV incidence increase), averted 118 HIV infections over remaining lifetimes and was cost saving. Lower effectiveness (64%) gave an incremental cost-effectiveness ratio of + GBP 23,500 (EUR 32,000) per quality-adjusted life year (QALY) gained. Investment of GBP 26.9 million (EUR 36.6 million) in year-1 breaks even anywhere from year-23 (86% effectiveness) to year-33 (64% effectiveness). PrEP cost-effectiveness was highly sensitive to year-1 HIV incidence, PrEP adherence/effectiveness, and antiretroviral drug costs. There is much uncertainty around HIV incidence in those given PrEP and adherence/effectiveness, especially under programme scale-up. Substantially reduced PrEP drug costs are needed to give the necessary assurance of cost-effectiveness, and for an affordable public health programme of sufficient size

HIV testing, risk perception, and behaviour in the British population.

OBJECTIVE: To examine the relationship between HIV risk behaviour, risk perception and testing in Britain. DESIGN: A probability sample survey of the British population. METHODS: We analyzed data on sexual behaviour, self-perceived HIV risk and HIV testing (excluding testing because of blood donation) from 13 751 sexually experienced men and women aged 16-74, interviewed between 2010 and 2012 using computer-assisted face-to-face and self-interviewing. RESULTS: Altogether, 3.5% of men and 5.4% of women reported having an HIV test in the past year. Higher perceived risk of HIV was associated with sexual risk behaviours and with HIV testing. However, the majority of those rating themselves as 'greatly' or 'quite a lot' at risk of HIV (3.4% of men, 2.5% of women) had not tested in the past year. This was also found among the groups most affected by HIV: MSM and black Africans. Within these groups, the majority reporting sexual risk behaviours did not perceive themselves as at risk and had not tested for HIV. Overall, 29.6% of men and 39.9% of women who tested for HIV in the past year could be classified as low risk across a range of measures. CONCLUSION: Most people who perceive themselves as at risk of HIV have not recently tested, including among MSM and black Africans. Many people tested in Britain are at low risk, reflecting current policy that aims to normalize testing. Strategies to further improve uptake of testing are needed, particularly in those at greatest risk, to further reduce undiagnosed HIV infection at late diagnoses

What are the characteristics of, and clinical outcomes in men who have sex with men prescribed HIV postexposure prophylaxis following sexual exposure (PEPSE) at sexual health clinics in England?

OBJECTIVES: To explore the risk factors for, and clinical outcomes in men who have sex with men (MSM) prescribed HIV postexposure prophylaxis following sexual exposure (PEPSE) at sexual health clinics (SHCs) in England. METHODS: National STI surveillance data were extracted from the genitourinary medicine clinic activity dataset (GUMCADv2) for 2011-2014. Quarterly and annual trends in the number of episodes where PEPSE was prescribed were analysed by gender and sexual risk. Risk factors associated with being prescribed PEPSE among MSM attendees were explored using univariable and multivariable logistic regression. Subsequent HIV acquisition from 4 months after initiating PEPSE was assessed using multivariable Cox proportional hazards models, stratified by clinical risk profiles. RESULTS: During 2011-2014, there were 24 004 episodes where PEPSE was prescribed at SHCs, of which 69% were to MSM. The number of episodes where PEPSE was prescribed to MSM increased from 2383 in 2011 to 5944 in 2014, and from 1384 to 2226 for heterosexual men and women. 15% of MSM attendees received two or more courses of PEPSE. Compared with MSM attendees not prescribed PEPSE, MSM prescribed PEPSE were significantly more likely to have been diagnosed with a bacterial STI in the previous 12 months (adjusted OR (95% CI)-gonorrhoea: 11.6 (10.5 to 12.8); chlamydia: 5.02 (4.46 to 5.67); syphilis: 2.25 (1.73 to 2.93)), and were more likely to subsequently acquire HIV (adjusted HR (aHR) (95% CI)-single PEPSE course: 2.54 (2.19 to 2.96); two or more PEPSE courses: aHR (95% CI) 4.80 (3.69 to 6.25)). The probability of HIV diagnosis was highest in MSM prescribed PEPSE who had also been diagnosed with a bacterial STI in the previous 12 months (aHR (95% CI): 6.61 (5.19 to 8.42)). CONCLUSIONS: MSM prescribed PEPSE are at high risk of subsequent HIV acquisition and our data show further risk stratification by clinical and PEPSE prescribing history is possible, which might inform clinical practice and HIV prevention initiatives in MSM

Refusal of HIV testing among black Africans attending sexual health clinics in England, 2014: a review of surveillance data.

OBJECTIVES: Black Africans are one of the key risk groups for HIV in the UK and, among those living with HIV, an estimated 16% and 12% of black African heterosexual men and women, respectively, are undiagnosed and at risk of unknowingly transmitting HIV to their sex partners. Increased HIV test uptake is needed to address this, but there is limited information on how frequently HIV test refusal occurs among those attending sexual health clinics (SHCs). We identified factors associated with HIV test refusal among black African SHC attendees. METHODS: Data on all SHC attendances in England in 2014 were obtained from the genitourinary medicine clinic activity dataset, the mandatory surveillance system for STIs. Analyses were restricted to attendances by HIV-negative black Africans, and bivariate and multivariable associations between demographic and clinical characteristics and HIV test refusal were assessed. All associations were determined using generalised estimating equations logistic regression, and adjusted ORs (aORs) with 95% CIs are reported. RESULTS: Black Africans made 80 743 attendances at SHCs in 2014 and refused an HIV test on 9021 (11.2%) occasions. HIV test refusal was significantly more likely in women (aOR (95% CI) 1.54 (1.46 to 1.62) vs heterosexual men), and those living in the most deprived areas (1.44 (1.24 to 1.67)), diagnosed with a new STI (1.26 (1.18 to 1.34)) or living in London (1.06 (1.01 to 1.12)). Test refusal was significantly less likely with increasing age (0.99 (0.99 to 0.99)) and men who have sex with men (0.52 (0.43 to 0.63) vs heterosexual men), and in those tested for HIV in the past year (0.85 (0.81 to 0.89)), born outside the UK (0.73 (0.69 to 0.77)) or those attending following partner notification (0.11 (0.03 to 0.38)). CONCLUSIONS: Targeted interventions are needed to improve HIV testing uptake and reduce undiagnosed HIV infection among black Africans attending SHCs, especially heterosexuals residing in deprived areas

Sexualised drug use in people attending sexual health clinics in England.

Recent evidence highlights an increase in ‘chemsex’, the use of recreational drugs during sex, in men who have sex with men (MSM) and an association with risky sexual behaviours and outbreaks of STIs.1 However, the extent of sexualised drug use in people attending sexual health clinics (SHCs) is unknown

Cost-effectiveness of pre-exposure prophylaxis for HIV prevention in men who have sex with men in the UK: a modelling study and health economic evaluation.

BACKGROUND: In the UK, HIV incidence among men who have sex with men (MSM) has remained high for several years, despite widespread use of antiretroviral therapy and high rates of virological suppression. Pre-exposure prophylaxis (PrEP) has been shown to be highly effective in preventing further infections in MSM, but its cost-effectiveness is uncertain. METHODS: In this modelling study and economic evaluation, we calibrated a dynamic, individual-based stochastic model, the HIV Synthesis Model, to multiple data sources (surveillance data provided by Public Health England and data from a large, nationally representative survey, Natsal-3) on HIV among MSM in the UK. We did a probabilistic sensitivity analysis (sampling 22 key parameters) along with a range of univariate sensitivity analyses to evaluate the introduction of a PrEP programme with sexual event-based use of emtricitabine and tenofovir for MSM who had condomless anal sexual intercourse in the previous 3 months, a negative HIV test at baseline, and a negative HIV test in the preceding year. The main model outcomes were the number of HIV infections, quality-adjusted life-years (QALYs), and costs. FINDINGS: Introduction of such a PrEP programme, with around 4000 MSM initiated on PrEP by the end of the first year and almost 40 000 by the end of the 15th year, would result in a total cost saving (£1·0 billion discounted), avert 25% of HIV infections (42% of which would be directly because of PrEP), and lead to a gain of 40 000 discounted QALYs over an 80-year time horizon. This result was particularly sensitive to the time horizon chosen, the cost of antiretroviral drugs (for treatment and PrEP), and the underlying trend in condomless sex. INTERPRETATION: This analysis suggests that the introduction of a PrEP programme for MSM in the UK is cost-effective and possibly cost-saving in the long term. A reduction in the cost of antiretroviral drugs (including the drugs used for PrEP) would substantially shorten the time for cost savings to be realised. FUNDING: National Institute for Health Research