Riviste scientifiche

What’s the best way to scare an elephant? Use an AI scarecrow

New Scientist - Gi, 16/11/2017 - 18:18
Elephants cause a lot of damage, but like other smart animals, they're too smart to scare away. An AI scarecrow that adapts its tactics for continuous scaring could be the answer

Why a female fly will ruin your drink, but a male is fine

New Scientist - Gi, 16/11/2017 - 16:31
We’re able to sense even tiny quantities of a female fruit fly pheromone, meaning one can ruin your wine no matter how quickly you remove it from your glass

Ancient skull from China may rewrite the origins of our species

New Scientist - Gi, 16/11/2017 - 15:08
The 260,000-year-old Dali skull was found in China, but it looks a lot like the earliest known members of our species – which were found in Africa

Brain training game linked to lower dementia risk a decade later

New Scientist - Gi, 16/11/2017 - 15:00
Could just ten sessions of brain training be enough to lower your risk of dementia by 29 per cent a decade later? A study suggests so, but some are sceptical

Amish gene can make them live 10 years longer and avoid diabetes

New Scientist - Me, 15/11/2017 - 19:00
A gene variant that arose six generations ago in an Amish group seems to make people carrying the gene live ten years longer, and protect them from diabetes

A layer of haze keeps Pluto’s atmosphere extremely cold

New Scientist - Me, 15/11/2017 - 19:00
Pluto is far from the sun, so astronomers expect its atmosphere to be cold, but it's colder than predicted. Now we know that soot sends the sun’s heat back into space

Free-fall experiment could test if gravity is a quantum force

New Scientist - Me, 15/11/2017 - 18:40
The effort to reconcile general relativity with quantum mechanics always hits one snag: gravity. An experiment could finally tell us if it is a quantum force

Spiders reset body clocks to avoid 5-hour jet-lag every day

New Scientist - Me, 15/11/2017 - 17:52
Some species of spider have short biological clocks that have to be reset each morning. Being out of sync with the 24-hour cycle in this way might help them avoid prey

We’ve just found a nearby exoplanet that could be right for life

New Scientist - Me, 15/11/2017 - 17:08
A newly discovered nearby world is probably close in size and temperature to Earth. This exoplanet might be able to host life because of its unusually calm star

The ‘space nation’ Asgardia just launched its first satellite

New Scientist - Me, 15/11/2017 - 15:30
Asgardia is a 'virtual nation' that says it aims to build sovereign colonies in space. On 12 November it launched a satellite carrying its citizens’ data

Porpoises twist laws of physics to aim their focused sonar beams

New Scientist - Me, 15/11/2017 - 12:45
Porpoises scrunch up their heads to direct their sonar beams and keep prey within "sight". Understanding how they point sound could help us design better sonar

Why we should build AI that sometimes disobeys our commands

New Scientist - Me, 15/11/2017 - 11:28
In our desire to make ethical artificial intelligence, we better be ready for machines that can choose to say no, says Jamais Cascio

Prospects for passive immunity to prevent HIV infection

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Lynn Morris, Nonhlanhla N. Mkhize

In a Perspective, Lynn Morris and Nonhlanhla Mkhize discuss the prospects for broadly neutralizing antibodies to be used in preventing HIV infection.

Safety, pharmacokinetics, and immunological activities of multiple intravenous or subcutaneous doses of an anti-HIV monoclonal antibody, VRC01, administered to HIV-uninfected adults: Results of a phase 1 randomized trial

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Kenneth H. Mayer, Kelly E. Seaton, Yunda Huang, Nicole Grunenberg, Abby Isaacs, Mary Allen, Julie E. Ledgerwood, Ian Frank, Magdalena E. Sobieszczyk, Lindsey R. Baden, Benigno Rodriguez, Hong Van Tieu, Georgia D. Tomaras, Aaron Deal, Derrick Goodman, Robert T. Bailer, Guido Ferrari, Ryan Jensen, John Hural, Barney S. Graham, John R. Mascola, Lawrence Corey, David C. Montefiori, on behalf of the HVTN 104 Protocol Team , and the NIAID HIV Vaccine Trials Network

Background

VRC01 is an HIV-1 CD4 binding site broadly neutralizing antibody (bnAb) that is active against a broad range of HIV-1 primary isolates in vitro and protects against simian-human immunodeficiency virus (SHIV) when delivered parenterally to nonhuman primates. It has been shown to be safe and well tolerated after short-term administration in humans; however, its clinical and functional activity after longer-term administration has not been previously assessed.

Methods and findings

HIV Vaccine Trials Network (HVTN) 104 was designed to evaluate the safety and tolerability of multiple doses of VRC01 administered either subcutaneously or by intravenous (IV) infusion and to assess the pharmacokinetics and in vitro immunologic activity of the different dosing regimens. Additionally, this study aimed to assess the effect that the human body has on the functional activities of VRC01 as measured by several in vitro assays. Eighty-eight healthy, HIV-uninfected, low-risk participants were enrolled in 6 United States clinical research sites affiliated with the HVTN between September 9, 2014, and July 15, 2015. The median age of enrollees was 27 years (range, 18–50); 52% were White (non-Hispanic), 25% identified as Black (non-Hispanic), 11% were Hispanic, and 11% were non-Hispanic people of diverse origins. Participants were randomized to receive the following: a 40 mg/kg IV VRC01 loading dose followed by five 20 mg/kg IV VRC01 doses every 4 weeks (treatment group 1 [T1], n = 20); eleven 5 mg/kg subcutaneous (SC) VRC01 (treatment group 3 [T3], n = 20); placebo (placebo group 3 [P3], n = 4) doses every 2 weeks; or three 40 mg/kg IV VRC01 doses every 8 weeks (treatment group 2 [T2], n = 20). Treatment groups T4 and T5 (n = 12 each) received three 10 or 30 mg/kg IV VRC01 doses every 8 weeks, respectively. Participants were followed for 32 weeks after their first VRC01 administration and received a total of 249 IV infusions and 208 SC injections, with no serious adverse events, dose-limiting toxicities, nor evidence for anti-VRC01 antibodies observed. Serum VRC01 levels were detected through 12 weeks after final administration in all participants who received all scheduled doses. Mean peak serum VRC01 levels of 1,177 μg/ml (95% CI: 1,033, 1,340) and 420 μg/ml (95% CI: 356, 494) were achieved 1 hour after the IV infusion series of 30 mg/kg and 10 mg/kg doses, respectively. Mean trough levels at week 24 in the IV infusion series of 30 mg/kg and 10 mg/kg doses, respectively, were 16 μg/ml (95% CI: 10, 27) and 6 μg/ml (95% CI: 5, 9) levels, which neutralize a majority of circulating strains in vitro (50% inhibitory concentration [IC50] > 5 μg/ml). Post-infusion/injection serum VRC01 retained expected functional activity (virus neutralization, antibody-dependent cellular cytotoxicity, phagocytosis, and virion capture). The limitations of this study include the relatively small sample size of each VRC01 administration regimen and missing data from participants who were unable to complete all study visits.

Conclusions

VRC01 administered as either an IV infusion (10–40 mg/kg) given monthly or bimonthly, or as an SC injection (5 mg/kg) every 2 weeks, was found to be safe and well tolerated. In addition to maintaining drug concentrations consistent with neutralization of the majority of tested HIV strains, VRC01 concentrations from participants’ sera were found to avidly capture HIV virions and to mediate antibody-dependent cellular phagocytosis, suggesting a range of anti-HIV immunological activities, warranting further clinical trials.

Trial registration

Clinical Trials Registration: NCT02165267

Treatment guidelines and early loss from care for people living with HIV in Cape Town, South Africa: A retrospective cohort study

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Ingrid T. Katz, Richard Kaplan, Garrett Fitzmaurice, Dominick Leone, David R. Bangsberg, Linda-Gail Bekker, Catherine Orrell

Background

South Africa has undergone multiple expansions in antiretroviral therapy (ART) eligibility from an initial CD4+ threshold of ≤200 cells/μl to providing ART for all people living with HIV (PLWH) as of September 2016. We evaluated the association of programmatic changes in ART eligibility with loss from care, both prior to ART initiation and within the first 16 weeks of starting treatment, during a period of programmatic expansion to ART treatment at CD4+ ≤ 350 cells/μl.

Methods and findings

We performed a retrospective cohort study of 4,025 treatment-eligible, non-pregnant PLWH accessing care in a community health center in Gugulethu Township affiliated with the Desmond Tutu HIV Centre in Cape Town. The median age of participants was 34 years (IQR 28–41 years), almost 62% were female, and the median CD4+ count was 173 cells/μl (IQR 92–254 cells/μl). Participants were stratified into 2 cohorts: an early cohort, enrolled into care at the health center from 1 January 2009 to 31 August 2011, when guidelines mandated that ART initiation required CD4+ ≤ 200 cells/μl, pregnancy, advanced clinical symptoms (World Health Organization [WHO] stage 4), or comorbidity (active tuberculosis); and a later cohort, enrolled into care from 1 September 2011 to 31 December 2013, when the treatment threshold had been expanded to CD4+ ≤ 350 cells/μl. Demographic and clinical factors were compared before and after the policy change using chi-squared tests to identify potentially confounding covariates, and logistic regression models were used to estimate the risk of pre-treatment (pre-ART) loss from care and early loss within the first 16 weeks on treatment, adjusting for age, baseline CD4+, and WHO stage. Compared with participants in the later cohort, participants in the earlier cohort had significantly more advanced disease: median CD4+ 146 cells/μl versus 214 cells/μl (p < 0.001), 61.1% WHO stage 3/4 disease versus 42.8% (p < 0.001), and pre-ART mortality of 34.2% versus 16.7% (p < 0.001). In total, 385 ART-eligible PLWH (9.6%) failed to initiate ART, of whom 25.7% died before ever starting treatment. Of the 3,640 people who started treatment, 58 (1.6%) died within the first 16 weeks in care, and an additional 644 (17.7%) were lost from care within 16 weeks of starting ART. PLWH who did start treatment in the later cohort were significantly more likely to discontinue care in <16 weeks (19.8% versus 15.8%, p = 0.002). After controlling for baseline CD4+, WHO stage, and age, this effect remained significant (adjusted odds ratio [aOR] = 1.30, 95% CI 1.09–1.55). As such, it remains unclear if early attrition from care was due to a “healthy cohort” effect or to overcrowding as programs expanded to accommodate the broader guidelines for treatment. Our findings were limited by a lack of generalizability (given that these data were from a single high-volume site where testing and treatment were available) and an inability to formally investigate the effect of crowding on the main outcome.

Conclusions

Over one-quarter of this ART-eligible cohort did not achieve the long-term benefits of treatment due to early mortality, ART non-initiation, or early ART discontinuation. Those who started treatment in the later cohort appeared to be more likely to discontinue care early, and this outcome appeared to be independent of CD4+ count or WHO stage. Future interventions should focus on those most at risk for early loss from care as programs continue to expand in South Africa.

A combination intervention strategy to improve linkage to and retention in HIV care following diagnosis in Mozambique: A cluster-randomized study

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Batya Elul, Matthew R. Lamb, Maria Lahuerta, Fatima Abacassamo, Laurence Ahoua, Stephanie A. Kujawski, Maria Tomo, Ilesh Jani

Background

Concerning gaps in the HIV care continuum compromise individual and population health. We evaluated a combination intervention strategy (CIS) targeting prevalent barriers to timely linkage and sustained retention in HIV care in Mozambique.

Methods and findings

In this cluster-randomized trial, 10 primary health facilities in the city of Maputo and Inhambane Province were randomly assigned to provide the CIS or the standard of care (SOC). The CIS included point-of-care CD4 testing at the time of diagnosis, accelerated ART initiation, and short message service (SMS) health messages and appointment reminders. A pre–post intervention 2-sample design was nested within the CIS arm to assess the effectiveness of CIS+, an enhanced version of the CIS that additionally included conditional non-cash financial incentives for linkage and retention. The primary outcome was a combined outcome of linkage to care within 1 month and retention at 12 months after diagnosis. From April 22, 2013, to June 30, 2015, we enrolled 2,004 out of 5,327 adults ≥18 years of age diagnosed with HIV in the voluntary counseling and testing clinics of participating health facilities: 744 (37%) in the CIS group, 493 (25%) in the CIS+ group, and 767 (38%) in the SOC group. Fifty-seven percent of the CIS group achieved the primary outcome versus 35% in the SOC group (relative risk [RR]CIS vs SOC = 1.58, 95% CI 1.05–2.39). Eighty-nine percent of the CIS group linked to care on the day of diagnosis versus 16% of the SOC group (RRCIS vs SOC = 9.13, 95% CI 1.65–50.40). There was no significant benefit of adding financial incentives to the CIS in terms of the combined outcome (55% of the CIS+ group achieved the primary outcome, RRCIS+ vs CIS = 0.96, 95% CI 0.81–1.16). Key limitations include the use of existing medical records to assess outcomes, the inability to isolate the effect of each component of the CIS, non-concurrent enrollment of the CIS+ group, and exclusion of many patients newly diagnosed with HIV.

Conclusions

The CIS showed promise for making much needed gains in the HIV care continuum in our study, particularly in the critical first step of timely linkage to care following diagnosis.

Trial registration

ClinicalTrials.gov NCT01930084

Virological response and resistance among HIV-infected children receiving long-term antiretroviral therapy without virological monitoring in Uganda and Zimbabwe: Observational analyses within the randomised ARROW trial

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Alexander J. Szubert, Andrew J. Prendergast, Moira J. Spyer, Victor Musiime, Philippa Musoke, Mutsa Bwakura-Dangarembizi, Patricia Nahirya-Ntege, Margaret J. Thomason, Emmanuel Ndashimye, Immaculate Nkanya, Oscar Senfuma, Boniface Mudenge, Nigel Klein, Diana M. Gibb, A. Sarah Walker, the ARROW Trial Team

Background

Although WHO recommends viral load (VL) monitoring for those on antiretroviral therapy (ART), availability in low-income countries remains limited. We investigated long-term VL and resistance in HIV-infected children managed without real-time VL monitoring.

Methods and findings

In the ARROW factorial trial, 1,206 children initiating ART in Uganda and Zimbabwe between 15 March 2007 and 18 November 2008, aged a median 6 years old, with median CD4% of 12%, were randomised to monitoring with or without 12-weekly CD4 counts and to receive 2 nucleoside reverse transcriptase inhibitors (2NRTI, mainly abacavir+lamivudine) with a non-nucleoside reverse transcriptase inhibitor (NNRTI) or 3 NRTIs as long-term ART. All children had VL assayed retrospectively after a median of 4 years on ART; those with >1,000 copies/ml were genotyped. Three hundred and sixteen children had VL and genotypes assayed longitudinally (at least every 24 weeks). Overall, 67 (6%) switched to second-line ART and 54 (4%) died. In children randomised to WHO-recommended 2NRTI+NNRTI long-term ART, 308/378 (81%) monitored with CD4 counts versus 297/375 (79%) without had VL <1,000 copies/ml at 4 years (difference = +2.3% [95% CI −3.4% to +8.0%]; P = 0.43), with no evidence of differences in intermediate/high-level resistance to 11 drugs. Among children with longitudinal VLs, only 5% of child-time post–week 24 was spent with persistent low-level viraemia (80–5,000 copies/ml) and 10% with VL rebound ≥5,000 copies/ml. No child resuppressed <80 copies/ml after confirmed VL rebound ≥5,000 copies/ml. A median of 1.0 (IQR 0.0,1.5) additional NRTI mutation accumulated over 2 years’ rebound. Nineteen out of 48 (40%) VLs 1,000–5,000 copies/ml were immediately followed by resuppression <1,000 copies/ml, but only 17/155 (11%) VLs ≥5,000 copies/ml resuppressed (P < 0.0001). Main study limitations are that analyses were exploratory and treatment initiation used 2006 criteria, without pre-ART genotypes.

Conclusions

In this study, children receiving first-line ART in sub-Saharan Africa without real-time VL monitoring had good virological and resistance outcomes over 4 years, regardless of CD4 monitoring strategy. Many children with detectable low-level viraemia spontaneously resuppressed, highlighting the importance of confirming virological failure before switching to second-line therapy. Children experiencing rebound ≥5,000 copies/ml were much less likely to resuppress, but NRTI resistance increased only slowly. These results are relevant to the increasing numbers of HIV-infected children receiving first-line ART in sub-Saharan Africa with limited access to virological monitoring.

Trial registration

ISRCTN Registry, ISRCTN24791884

Bioequivalence of twice-daily oral tacrolimus in transplant recipients: More evidence for consensus?

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Simon Ball

In this Perspective on the clinical trial by Rita Alloway and colleagues, Simon Ball explains the benefits to healthcare systems and individual patients of the bioequivalence established between generic and brand-name formulations of an immunosuppressive drug in transplant recipients.

Bioequivalence between innovator and generic tacrolimus in liver and kidney transplant recipients: A randomized, crossover clinical trial

PLoS Medicine - Ma, 14/11/2017 - 23:00

by Rita R. Alloway, Alexander A. Vinks, Tsuyoshi Fukuda, Tomoyuki Mizuno, Eileen C. King, Yuanshu Zou, Wenlei Jiang, E. Steve Woodle, Simon Tremblay, Jelena Klawitter, Jost Klawitter, Uwe Christians

Background

Although the generic drug approval process has a long-term successful track record, concerns remain for approval of narrow therapeutic index generic immunosuppressants, such as tacrolimus, in transplant recipients. Several professional transplant societies and publications have generated skepticism of the generic approval process. Three major areas of concern are that the pharmacokinetic properties of generic products and the innovator (that is, “brand”) product in healthy volunteers may not reflect those in transplant recipients, bioequivalence between generic and innovator may not ensure bioequivalence between generics, and high-risk patients may have specific bioequivalence concerns. Such concerns have been fueled by anecdotal observations and retrospective and uncontrolled published studies, while well-designed, controlled prospective studies testing the validity of the regulatory bioequivalence testing approach for narrow therapeutic index immunosuppressants in transplant recipients have been lacking. Thus, the present study prospectively assesses bioequivalence between innovator tacrolimus and 2 generics in individuals with a kidney or liver transplant.

Methods and findings

From December 2013 through October 2014, a prospective, replicate dosing, partially blinded, randomized, 3-treatment, 6-period crossover bioequivalence study was conducted at the University of Cincinnati in individuals with a kidney (n = 35) or liver transplant (n = 36). Abbreviated New Drug Applications (ANDA) data that included manufacturing and healthy individual pharmacokinetic data for all generics were evaluated to select the 2 most disparate generics from innovator, and these were named Generic Hi and Generic Lo. During the 8-week study period, pharmacokinetic studies assessed the bioequivalence of Generic Hi and Generic Lo with the Innovator tacrolimus and with each other. Bioequivalence of the major tacrolimus metabolite was also assessed. All products fell within the US Food and Drug Administration (FDA) average bioequivalence (ABE) acceptance criteria of a 90% confidence interval contained within the confidence limits of 80.00% and 125.00%. Within-subject variability was similar for the area under the curve (AUC) (range 12.11–15.81) and the concentration maximum (Cmax) (range 17.96–24.72) for all products. The within-subject variability was utilized to calculate the scaled average bioequivalence (SCABE) 90% confidence interval. The calculated SCABE 90% confidence interval was 84.65%–118.13% and 80.00%–125.00% for AUC and Cmax, respectively. The more stringent SCABE acceptance criteria were met for all product comparisons for AUC and Cmax in both individuals with a kidney transplant and those with a liver transplant. European Medicines Agency (EMA) acceptance criteria for narrow therapeutic index drugs were also met, with the only exception being in the case of Brand versus Generic Lo, in which the upper limits of the 90% confidence intervals were 111.30% (kidney) and 112.12% (liver). These were only slightly above the upper EMA acceptance criteria limit for an AUC of 111.11%. SCABE criteria were also met for the major tacrolimus metabolite 13-O-desmethyl tacrolimus for AUC, but it failed the EMA criterion. No acute rejections, no differences in renal function in all individuals, and no differences in liver function were observed in individuals with a liver transplant using the Tukey honest significant difference (HSD) test for multiple comparisons. Fifty-two percent and 65% of all individuals with a kidney or liver transplant, respectively, reported an adverse event. The Exact McNemar test for paired categorical data with adjustments for multiple comparisons was used to compare adverse event rates among the products. No statistically significant differences among any pairs of products were found for any adverse event code or for adverse events overall. Limitations of this study include that the observations were made under strictly controlled conditions that did not allow for the impact of nonadherence or feeding on the possible pharmacokinetic differences. Generic Hi and Lo were selected based upon bioequivalence data in healthy volunteers because no pharmacokinetic data in recipients were available for all products. The safety data should be interpreted in light of the small number of participants and the short observation periods. Lastly, only the 1 mg tacrolimus strength was utilized in this study.

Conclusions

Using an innovative, controlled bioequivalence study design, we observed equivalence between tacrolimus innovator and 2 generic products as well as between 2 generic products in individuals after kidney or liver transplantation following current FDA bioequivalence metrics. These results support the position that bioequivalence for the narrow therapeutic index drug tacrolimus translates from healthy volunteers to individuals receiving a kidney or liver transplant and provides evidence that generic products that are bioequivalent with the innovator product are also bioequivalent to each other.

Trial registration

ClinicalTrials.gov NCT01889758.

Association between the 2012 Health and Social Care Act and specialist visits and hospitalisations in England: A controlled interrupted time series analysis

PLoS Medicine - Ma, 14/11/2017 - 23:00

by James A. Lopez Bernal, Christine Y. Lu, Antonio Gasparrini, Steven Cummins, J. Frank Wharham, Steven B. Soumerai

Background

The 2012 Health and Social Care Act (HSCA) in England led to among the largest healthcare reforms in the history of the National Health Service (NHS). It gave control of £67 billion of the NHS budget for secondary care to general practitioner (GP) led Clinical Commissioning Groups (CCGs). An expected outcome was that patient care would shift away from expensive hospital and specialist settings, towards less expensive community-based models. However, there is little evidence for the effectiveness of this approach. In this study, we aimed to assess the association between the NHS reforms and hospital admissions and outpatient specialist visits.

Methods and findings

We conducted a controlled interrupted time series analysis to examine rates of outpatient specialist visits and inpatient hospitalisations before and after the implementation of the HSCA. We used national routine hospital administrative data (Hospital Episode Statistics) on all NHS outpatient specialist visits and inpatient hospital admissions in England between 2007 and 2015 (with a mean of 26.8 million new outpatient visits and 14.9 million inpatient admissions per year). As a control series, we used equivalent data on hospital attendances in Scotland. Primary outcomes were: total, elective, and emergency hospitalisations, and total and GP-referred specialist visits. Both countries had stable trends in all outcomes at baseline. In England, after the policy, there was a 1.1% (95% CI 0.7%–1.5%; p < 0.001) increase in total specialist visits per quarter and a 1.6% increase in GP-referred specialist visits (95% CI 1.2%–2.0%; p < 0.001) per quarter, equivalent to 12.7% (647,000 over the 5,105,000 expected) and 19.1% (507,000 over the 2,658,000 expected) more visits per quarter by the end of 2015, respectively. In Scotland, there was no change in specialist visits. Neither country experienced a change in trends in hospitalisations: change in slope for total, elective, and emergency hospitalisations were −0.2% (95% CI −0.6%–0.2%; p = 0.257), −0.2% (95% CI −0.6%–0.1%; p = 0.235), and 0.0% (95% CI −0.5%–0.4%; p = 0.866) per quarter in England. We are unable to exclude confounding due to other events occurring around the time of the policy. However, we limited the likelihood of such confounding by including relevant control series, in which no changes were seen.

Conclusions

Our findings suggest that giving control of healthcare budgets to GP-led CCGs was not associated with a reduction in overall hospitalisations and was associated with an increase in specialist visits.

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