Riviste scientifiche

Making your brain cells longer could help ward off Alzheimer’s

New Scientist - Me, 22/11/2017 - 12:55
People who die with plaques and tangles in their brain but no signs of dementia may have changed the shape of connections between neurons to withstand the disease

[Editorial] Heart failure in an ageing population

The Lancet - Me, 22/11/2017 - 09:44
An Article by Nathalie Conrad and colleagues published online on Nov 21 in The Lancet provides the most comprehensive epidemiology to date of the changing burden of heart failure in the UK according to age, sex, regional location, and socioeconomic status. Their data show an increase in the number of new heart failure diagnoses, at least partly because of an ageing population. Comorbidities also continued to increase for multiple chronic conditions such as hypertension, atrial fibrillation, diabetes, cancer, and osteoarthritis.

Lansoprazole use and tuberculosis incidence in the United Kingdom Clinical Practice Research Datalink: A population based cohort

PLoS Medicine - Ma, 21/11/2017 - 23:00

by Tom A. Yates, Laurie A. Tomlinson, Krishnan Bhaskaran, Sinead Langan, Sara Thomas, Liam Smeeth, Ian J. Douglas

Background

Recent in vitro and animal studies have found the proton pump inhibitor (PPI) lansoprazole to be highly active against Mycobacterium tuberculosis. Omeprazole and pantoprazole have no activity. There is no evidence that, in clinical practice, lansoprazole can treat or prevent incident tuberculosis (TB) disease.

Methods and findings

We studied a cohort of new users of lansoprazole, omeprazole, or pantoprazole from the United Kingdom Clinical Practice Research Datalink to determine whether lansoprazole users have a lower incidence of TB disease than omeprazole or pantoprazole users. Negative control outcomes of myocardial infarction (MI) and herpes zoster were also studied. Multivariable Cox proportional hazards regression was used to adjust for potential confounding by a wide range of factors. We identified 527,364 lansoprazole initiators and 923,500 omeprazole or pantoprazole initiators. Lansoprazole users had a lower rate of TB disease (n = 86; 10.0 cases per 100,000 person years; 95% confidence interval 8.1–12.4) than omeprazole or pantoprazole users (n = 193; 15.3 cases per 100,000 person years; 95% confidence interval 13.3–17.7), with an adjusted hazard ratio (HR) of 0.68 (0.52–0.89). No association was found with MI (adjusted HR 1.04; 95% confidence interval 1.00–1.08) or herpes zoster (adjusted HR 1.03; 95% confidence interval 1.00–1.06). Limitations of this study are that we could not determine whether TB disease was due to reactivation of latent infection or a result of recent transmission, nor could we determine whether lansoprazole would have a beneficial effect if given to people presenting with TB disease.

Conclusions

In this study, use of the commonly prescribed and cheaply available PPI lansoprazole was associated with reduced incidence of TB disease. Given the serious problem of drug resistance and the adverse side effect profiles of many TB drugs, further investigation of lansoprazole as a potential antituberculosis agent is warranted.

The US President's Malaria Initiative, <i>Plasmodium falciparum</i> transmission and mortality: A modelling study

PLoS Medicine - Ma, 21/11/2017 - 23:00

by Peter Winskill, Hannah C. Slater, Jamie T. Griffin, Azra C. Ghani, Patrick G. T. Walker

Background

Although significant progress has been made in reducing malaria transmission globally in recent years, a large number of people remain at risk and hence the gains made are fragile. Funding lags well behind amounts needed to protect all those at risk and ongoing contributions from major donors, such as the President’s Malaria Initiative (PMI), are vital to maintain progress and pursue further reductions in burden. We use a mathematical modelling approach to estimate the impact of PMI investments to date in reducing malaria burden and to explore the potential negative impact on malaria burden should a proposed 44% reduction in PMI funding occur.

Methods and findings

We combined an established mathematical model of Plasmodium falciparum transmission dynamics with epidemiological, intervention, and PMI-financing data to estimate the contribution PMI has made to malaria control via funding for long-lasting insecticide treated nets (LLINs), indoor residual spraying (IRS), and artemisinin combination therapies (ACTs). We estimate that PMI has prevented 185 million (95% CrI: 138 million, 230 million) malaria cases and saved 940,049 (95% CrI: 545,228, 1.4 million) lives since 2005. If funding is maintained, PMI-funded interventions are estimated to avert a further 162 million (95% CrI: 116 million, 194 million) cases, saving a further 692,589 (95% CrI: 392,694, 955,653) lives between 2017 and 2020. With an estimate of US$94 (95% CrI: US$51, US$166) per Disability Adjusted Life Year (DALY) averted, PMI-funded interventions are highly cost-effective. We also demonstrate the further impact of this investment by reducing caseloads on health systems. If a 44% reduction in PMI funding were to occur, we predict that this loss of direct aid could result in an additional 67 million (95% CrI: 49 million, 82 million) cases and 290,649 (95% CrI: 167,208, 395,263) deaths between 2017 and 2020. We have not modelled indirect impacts of PMI funding (such as health systems strengthening) in this analysis.

Conclusions

Our model estimates that PMI has played a significant role in reducing malaria cases and deaths since its inception. Reductions in funding to PMI could lead to large increases in the number of malaria cases and deaths, damaging global goals of malaria control and elimination.

The value of confirmatory testing in early infant HIV diagnosis programmes in South Africa: A cost-effectiveness analysis

PLoS Medicine - Ma, 21/11/2017 - 23:00

by Lorna Dunning, Jordan A. Francke, Divya Mallampati, Rachel L. MacLean, Martina Penazzato, Taige Hou, Landon Myer, Elaine J. Abrams, Rochelle P. Walensky, Valériane Leroy, Kenneth A. Freedberg, Andrea Ciaranello

Background

The specificity of nucleic acid amplification tests (NAATs) used for early infant diagnosis (EID) of HIV infection is <100%, leading some HIV-uninfected infants to be incorrectly identified as HIV-infected. The World Health Organization recommends that infants undergo a second NAAT to confirm any positive test result, but implementation is limited. Our objective was to determine the impact and cost-effectiveness of confirmatory HIV testing for EID programmes in South Africa.

Method and findings

Using the Cost-effectiveness of Preventing AIDS Complications (CEPAC)–Pediatric model, we simulated EID testing at age 6 weeks for HIV-exposed infants without and with confirmatory testing. We assumed a NAAT cost of US$25, NAAT specificity of 99.6%, NAAT sensitivity of 100% for infants infected in pregnancy or at least 4 weeks prior to testing, and a mother-to-child transmission (MTCT) rate at 12 months of 4.9%; we simulated guideline-concordant rates of testing uptake, result return, and antiretroviral therapy (ART) initiation (100%). After diagnosis, infants were linked to and retained in care for 10 years (false-positive) or lifelong (true-positive). All parameters were varied widely in sensitivity analyses. Outcomes included number of infants with false-positive diagnoses linked to ART per 1,000 ART initiations, life expectancy (LE, in years) and per-person lifetime HIV-related healthcare costs. Both without and with confirmatory testing, LE was 26.2 years for HIV-infected infants and 61.4 years for all HIV-exposed infants; clinical outcomes for truly infected infants did not differ by strategy. Without confirmatory testing, 128/1,000 ART initiations were false-positive diagnoses; with confirmatory testing, 1/1,000 ART initiations were false-positive diagnoses. Because confirmatory testing averted costly HIV care and ART in truly HIV-uninfected infants, it was cost-saving: total cost US$1,790/infant tested, compared to US$1,830/infant tested without confirmatory testing. Confirmatory testing remained cost-saving unless NAAT cost exceeded US$400 or the HIV-uninfected status of infants incorrectly identified as infected was ascertained and ART stopped within 3 months of starting. Limitations include uncertainty in the data used in the model, which we examined with sensitivity and uncertainty analyses. We also excluded clinical harms to HIV-uninfected infants incorrectly treated with ART after false-positive diagnosis (e.g., medication toxicities); including these outcomes would further increase the value of confirmatory testing.

Conclusions

Without confirmatory testing, in settings with MTCT rates similar to that of South Africa, more than 10% of infants who initiate ART may reflect false-positive diagnoses. Confirmatory testing prevents inappropriate HIV diagnosis, is cost-saving, and should be adopted in all EID programmes.

HIV pre-exposure prophylaxis and early antiretroviral treatment among female sex workers in South Africa: Results from a prospective observational demonstration project

PLoS Medicine - Ma, 21/11/2017 - 23:00

by Robyn Eakle, Gabriela B. Gomez, Niven Naicker, Rutendo Bothma, Judie Mbogua, Maria A. Cabrera Escobar, Elaine Saayman, Michelle Moorhouse, W. D. Francois Venter, Helen Rees, on behalf of the TAPS Demonstration Project Team

Background

Operational research is required to design delivery of pre-exposure prophylaxis (PrEP) and early antiretroviral treatment (ART). This paper presents the primary analysis of programmatic data, as well as demographic, behavioural, and clinical data, from the TAPS Demonstration Project, which offered both interventions to female sex workers (FSWs) at 2 urban clinic sites in South Africa.

Methods and findings

The TAPS study was conducted between 30 March 2015 and 30 June 2017, with the enrolment period ending on 31 July 2016. TAPS was a prospective observational cohort study with 2 groups receiving interventions delivered in existing service settings: (1) PrEP as part of combination prevention for HIV-negative FSWs and (2) early ART for HIV-positive FSWs. The main outcome was programme retention at 12 months of follow-up. Of the 947 FSWs initially seen in clinic, 692 were HIV tested. HIV prevalence was 49%. Among those returning to clinic after HIV testing and clinical screening, 93% of the women who were HIV-negative were confirmed as clinically eligible for PrEP (n = 224/241), and 41% (n = 110/270) of the women who were HIV-positive had CD4 counts within National Department of Health ART initiation guidelines at assessment. Of the remaining women who were HIV-positive, 93% were eligible for early ART (n = 148/160). From those eligible, 98% (n = 219/224) and 94% (n = 139/148) took up PrEP and early ART, respectively. At baseline, a substantial fraction of women had a steady partner, worked in brothels, and were born in Zimbabwe. Of those enrolled, 22% on PrEP (n = 49/219) and 60% on early ART (n = 83/139) were seen at 12 months; we observed high rates of loss to follow-up: 71% (n = 156/219) and 30% (n = 42/139) in the PrEP and early ART groups, respectively. Little change over time was reported in consistent condom use or the number of sexual partners in the last 7 days, with high levels of consistent condom use with clients and low use with steady partners in both study groups. There were no seroconversions on PrEP and 7 virological failures on early ART among women remaining in the study. Reported adherence to PrEP varied over time between 70% and 85%, whereas over 90% of participants reported taking pills daily while on early ART. Data on provider-side costs were also collected and analysed. The total cost of service delivery was approximately US$126 for PrEP and US$406 for early ART per person-year. The main limitations of this study include the lack of a control group, which was not included due to ethical considerations; clinical study requirements imposed when PrEP was not approved through the regulatory system, which could have affected uptake; and the timing of the implementation of a national sex worker HIV programme, which could have also affected uptake and retention.

Conclusions

PrEP and early ART services can be implemented within FSW routine services in high prevalence, urban settings. We observed good uptake for both PrEP and early ART; however, retention rates for PrEP were low. Retention rates for early ART were similar to retention rates for the current standard of care. While the cost of the interventions was higher than previously published, there is potential for cost reduction at scale. The TAPS Demonstration Project results provided the basis for the first government PrEP and early ART guidelines and the rollout of the national sex worker HIV programme in South Africa.

Closing the gaps in the HIV care continuum

PLoS Medicine - Ma, 21/11/2017 - 23:00

by Ruanne V. Barnabas, Connie Celum

In a Perspective, Ruanne Barnabas and Connie Celum discuss the implications of the accompanying Link4Health and Engage4Health studies for HIV care in sub-Saharan Africa

HIV self-testing among female sex workers in Zambia: A cluster randomized controlled trial

PLoS Medicine - Ma, 21/11/2017 - 23:00

by Michael M. Chanda, Katrina F. Ortblad, Magdalene Mwale, Steven Chongo, Catherine Kanchele, Nyambe Kamungoma, Andrew Fullem, Caitlin Dunn, Leah G. Barresi, Guy Harling, Till Bärnighausen, Catherine E. Oldenburg

Background

HIV self-testing (HIVST) may play a role in addressing gaps in HIV testing coverage and as an entry point for HIV prevention services. We conducted a cluster randomized trial of 2 HIVST distribution mechanisms compared to the standard of care among female sex workers (FSWs) in Zambia.

Methods and findings

Trained peer educators in Kapiri Mposhi, Chirundu, and Livingstone, Zambia, each recruited 6 FSW participants. Peer educator–FSW groups were randomized to 1 of 3 arms: (1) delivery (direct distribution of an oral HIVST from the peer educator), (2) coupon (a coupon for collection of an oral HIVST from a health clinic/pharmacy), or (3) standard-of-care HIV testing. Participants in the 2 HIVST arms received 2 kits: 1 at baseline and 1 at 10 weeks. The primary outcome was any self-reported HIV testing in the past month at the 1- and 4-month visits, as HIVST can replace other types of HIV testing. Secondary outcomes included linkage to care, HIVST use in the HIVST arms, and adverse events. Participants completed questionnaires at 1 and 4 months following peer educator interventions. In all, 965 participants were enrolled between September 16 and October 12, 2016 (delivery, N = 316; coupon, N = 329; standard of care, N = 320); 20% had never tested for HIV. Overall HIV testing at 1 month was 94.9% in the delivery arm, 84.4% in the coupon arm, and 88.5% in the standard-of-care arm (delivery versus standard of care risk ratio [RR] = 1.07, 95% CI 0.99–1.15, P = 0.10; coupon versus standard of care RR = 0.95, 95% CI 0.86–1.05, P = 0.29; delivery versus coupon RR = 1.13, 95% CI 1.04–1.22, P = 0.005). Four-month rates were 84.1% for the delivery arm, 79.8% for the coupon arm, and 75.1% for the standard-of-care arm (delivery versus standard of care RR = 1.11, 95% CI 0.98–1.27, P = 0.11; coupon versus standard of care RR = 1.06, 95% CI 0.92–1.22, P = 0.42; delivery versus coupon RR = 1.05, 95% CI 0.94–1.18, P = 0.40). At 1 month, the majority of HIV tests were self-tests (88.4%). HIV self-test use was higher in the delivery arm compared to the coupon arm (RR = 1.14, 95% CI 1.05–1.23, P = 0.001) at 1 month, but there was no difference at 4 months. Among participants reporting a positive HIV test at 1 (N = 144) and 4 months (N = 235), linkage to care was non-significantly lower in the 2 HIVST arms compared to the standard-of-care arm. There were 4 instances of intimate partner violence related to study participation, 3 of which were related to HIV self-test use. Limitations include the self-reported nature of study outcomes and overall high uptake of HIV testing.

Conclusions

In this study among FSWs in Zambia, we found that HIVST was acceptable and accessible. However, HIVST may not substantially increase HIV cascade progression in contexts where overall testing and linkage are already high.

Trial registration

ClinicalTrials.gov NCT02827240

Ocean-covered planets may not be the places to search for life

New Scientist - Ma, 21/11/2017 - 18:17
Looking for life in the universe has often come down to a search for water on other planets. But water worlds may not make enough of the nutrients life needs

Keystone XL oil pipeline will go ahead despite last week’s spill

New Scientist - Ma, 21/11/2017 - 17:00
Last week the Keystone pipeline spilled 5,000 barrels of oil. This week Nebraska decided to allow the Keystone XL extension to be built right through the state

Latest climate talks actually made progress despite US obstinacy

New Scientist - Ma, 21/11/2017 - 16:30
While the US tried to promote “clean coal” at the COP23 Bonn climate meeting, other countries called for the dirty fossil fuel to be rapidly phased out

How a tiny fly can ‘scuba dive’ in a salty and toxic lake

New Scientist - Lu, 20/11/2017 - 21:00
Alkali flies plunge into the salty and alkaline Mono Lake, to feed and lay their eggs, but until now it has been unclear how they manage to survive

The message we’re sending to nearby aliens is no threat to Earth

New Scientist - Lu, 20/11/2017 - 18:45
Critics fear provoking hostile extraterrestrials by beaming messages to our closest exoplanets but there's no need to worry, says METI president Douglas Vakoch

Nothing you can do stops this code from watching you online

New Scientist - Lu, 20/11/2017 - 18:40
Code originally written to optimise websites bypasses https and incognito browsing to harvest and share everything you type online, from passwords to sensitive medical data

Whales switch from right to left-handed when diving for food

New Scientist - Lu, 20/11/2017 - 18:37
A study using video cameras attached to the backs of whales has shown how they switch laterality when feeding

Spongy clay might create huge water deposits deep inside Earth

New Scientist - Lu, 20/11/2017 - 17:00
We might finally know how ocean-sized deposits of water hundreds of kilometres below Earth's surface are getting there: a spongy sort of clay that is bringing it underground

Common condition endometriosis reprograms brain for depression

New Scientist - Lu, 20/11/2017 - 13:01
Endometriosis causes symptoms of mental health problems in mice, and the one in ten women who have the condition are more likely to have depression or anxiety

The New Horizons spacecraft is heading towards a mystery rock

New Scientist - Lu, 20/11/2017 - 12:00
After its visit to Pluto, the New Horizons spacecraft is travelling through the Kuiper belt towards what seems to be one rock - but what if it's actually two?

Lightning leaves clouds of radiation and antimatter in its wake

New Scientist - Sa, 18/11/2017 - 01:00
A lightning storm can trigger an atmospheric nuclear reaction that leads to the production of antimatter and radiation, which may pose health risks

[Editorial] Alcohol and cancer

The Lancet - Sa, 18/11/2017 - 00:00
The Nov 7 publication of Alcohol and Cancer: a Statement of the American Society of Clinical Oncology (ASCO) emphasises the prominence of alcohol as a proven cause of many cancers. This view is not novel and comes exactly 30 years after a working group of the International Agency for Research on Cancer determined that alcoholic beverages were carcinogenic to humans. It has been echoed by other cancer societies since then but seemingly ignored by the wider medical community and by society. The influential endorsement by ASCO provides a powerful impetus to act on decades of evidence that alcohol harms health.
Condividi contenuti