Riviste scientifiche

Climate change could wipe out many food cereals by 2070

New Scientist - %age fa
With their ability to adapt to climate change outstripped by rate of global warming, many grasses, such as wheat, rice and corn may be doomed

Improving Research into Models of Maternity Care to Inform Decision Making

PLoS Medicine - Ma, 27/09/2016 - 23:00

by Ank de Jonge, Jane Sandall

In a Perspective, Ank de Jonge and Jane Sandall discuss research on models of maternity care led by midwives.

A Comparison of Midwife-Led and Medical-Led Models of Care and Their Relationship to Adverse Fetal and Neonatal Outcomes: A Retrospective Cohort Study in New Zealand

PLoS Medicine - Ma, 27/09/2016 - 23:00

by Ellie Wernham, Jason Gurney, James Stanley, Lis Ellison-Loschmann, Diana Sarfati

Background

Internationally, a typical model of maternity care is a medically led system with varying levels of midwifery input. New Zealand has a midwife-led model of care, and there are movements in other countries to adopt such a system. There is a paucity of systemic evaluation that formally investigates safety-related outcomes in relationship to midwife-led care within an entire maternity service. The main objective of this study was to compare major adverse perinatal outcomes between midwife-led and medical-led maternity care in New Zealand.

Methods and Findings

This was a population-based retrospective cohort study. Participants were mother/baby pairs for all 244,047 singleton, term deliveries occurring between 1 January 2008 and 31 December 2012 in New Zealand in which no major fetal, neonatal, chromosomal or metabolic abnormality was identified and the mother was first registered with a midwife, obstetrician, or general practitioner as lead maternity carer. Main outcome measures were low Apgar score at five min, intrauterine hypoxia, birth-related asphyxia, neonatal encephalopathy, small for gestational age (as a negative control), and mortality outcomes (perinatal related mortality, stillbirth, and neonatal mortality). Logistic regression models were fitted, with crude and adjusted odds ratios (ORs) generated for each outcome for midwife-led versus medical-led care (based on lead maternity carer at first registration) with 95% confidence intervals. Fully adjusted models included age, ethnicity, deprivation, trimester of registration, parity, smoking, body mass index (BMI), and pre-existing diabetes and/or hypertension in the model. Of the 244,047 pregnancies included in the study, 223,385 (91.5%) were first registered with a midwife lead maternity carer, and 20,662 (8.5%) with a medical lead maternity carer. Adjusted ORs showed that medical-led births were associated with lower odds of an Apgar score of less than seven at 5 min (OR 0.52; 95% confidence interval 0.43–0.64), intrauterine hypoxia (OR 0.79; 0.62–1.02), birth-related asphyxia (OR 0.45; 0.32–0.62), and neonatal encephalopathy (OR 0.61; 0.38–0.97). No association was found between lead carer at first registration and being small for gestational age (SGA), which was included as a negative control (OR 1.00; 0.95–1.05). It was not possible to definitively determine whether one model of care was associated with fewer infant deaths, with ORs for the medical-led model compared with the midwife-led model being 0.80 (0.54–1.19) for perinatal related mortality, 0.86 (0.55–1.34) for stillbirth, and 0.62 (0.25–1.53) for neonatal mortality. Major limitations were related to the use of routine data in which some variables lacked detail; for example, we were unable to differentiate the midwife-led group into those who had received medical input during pregnancy and those who had not.

Conclusions

There is an unexplained excess of adverse events in midwife-led deliveries in New Zealand where midwives practice autonomously. The findings are of concern and demonstrate a need for further research that specifically investigates the reasons for the apparent excess of adverse outcomes in mothers with midwife-led care. These findings should be interpreted in the context of New Zealand’s internationally comparable birth outcomes and in the context of research that supports the many benefits of midwife-led care, such as greater patient satisfaction and lower intervention rates.

Tenofovir Pre-exposure Prophylaxis for Pregnant and Breastfeeding Women at Risk of HIV Infection: The Time is Now

PLoS Medicine - Ma, 27/09/2016 - 23:00

by Lynne M. Mofenson

In this Perspective, Lynne Mofenson discusses the implications of Mugwanya and colleagues' findings for protection of women against HIV infection during breastfeeding.

Pre-exposure Prophylaxis Use by Breastfeeding HIV-Uninfected Women: A Prospective Short-Term Study of Antiretroviral Excretion in Breast Milk and Infant Absorption

PLoS Medicine - Ma, 27/09/2016 - 23:00

by Kenneth K. Mugwanya, Craig W. Hendrix, Nelly R. Mugo, Mark Marzinke, Elly T. Katabira, Kenneth Ngure, Nulu B. Semiyaga, Grace John-Stewart, Timothy R. Muwonge, Gabriel Muthuri, Andy Stergachis, Connie L. Celum, Jared M. Baeten

Background

As pre-exposure prophylaxis (PrEP) becomes more widely used in heterosexual populations, an important consideration is its safety in infants who are breastfed by women taking PrEP. We investigated whether tenofovir and emtricitabine are excreted into breast milk and then absorbed by the breastfeeding infant in clinically significant concentrations when used as PrEP by lactating women.

Methods and Findings

We conducted a prospective short-term, open-label study of daily oral emtricitabine–tenofovir disoproxil fumarate PrEP among 50 HIV-uninfected breastfeeding African mother–infant pairs between 1–24 wk postpartum (ClinicalTrials.gov Identifier: NCT02776748). The primary goal was to quantify the steady-state concentrations of tenofovir and emtricitabine in infant plasma ingested via breastfeeding. PrEP was administered to women through daily directly observed therapy (DOT) for ten consecutive days and then discontinued thereafter. Non-fasting peak and trough samples of maternal plasma and breast milk were obtained at drug concentration steady states on days 7 and 10, and a single infant plasma sample was obtained on day 7. Peak blood and breast milk samples were obtained 1–2 h after the maternal DOT PrEP dose, while maternal trough samples were obtained at the end of the PrEP dosing interval (i.e., 23 to 24 h) after maternal DOT PrEP dose. Tenofovir and emtricitabine concentrations were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays.Of the 50 mother–infant pairs enrolled, 48% were ≤12 wk and 52% were 13–24 wk postpartum, and median maternal age was 25 y (interquartile range [IQR] 22–28). During study follow-up, the median (IQR) daily reported frequency of infant breastfeeding was 15 times (12 to 18) overall, 16 (14 to 19) for the ≤12 weeks, and 14 (12 to 17) for the 13–24 wk infant age groups. Overall, median (IQR) time-averaged peak concentrations in breast milk were 3.2 ng/mL (2.3 to 4.7) for tenofovir and 212.5 ng/mL (140.0 to 405.0) for emtricitabine. Similarly, median (IQR) time-averaged trough concentrations in breast milk were 3.3 ng/mL (2.3 to 4.4) for tenofovir and 183.0 ng/mL (113.0 to 250.0) for emtricitabine, reflecting trough-to-peak breast milk concentration ratios of 1.0 for tenofovir and 0.8 for emtricitabine, respectively. In infant plasma, tenofovir was unquantifiable in 46/49 samples (94%), but emtricitabine was detectable in 47/49 (96%) (median [IQR] concentration: 13.2 ng/mL [9.3 to 16.7]). The estimated equivalent doses an infant would ingest daily from breastfeeding were 0.47 μg/kg (IQR 0.35 to 0.71) for tenofovir and 31.9 μg/kg (IQR 21.0 to 60.8) for emtricitabine, translating into a <0.01% and 0.5% relative dose when compared to the 6 mg/kg dose that is proposed for therapeutic treatment of infant HIV infection and for prevention of infant postnatal HIV infection; a dose that has not shown safety concerns. No serious adverse effects were recorded during study follow-up.The key study limitation was that only a single infant sample was collected to minimize venipunctures for the children. However, maternal daily DOT and specimen collection at drug concentration steady state provided an adequate approach to address the key research question. Importantly, there was minimal variation in breast milk concentrations of tenofovir and emtricitabine (respective median trough-to-peak concentration ratio ~1), demonstrating that infants were exposed to consistent drug dosing via breast milk.

Conclusion

In this short-term study of daily directly observed oral PrEP in HIV-uninfected breastfeeding women, the estimated infant doses from breast milk and resultant infant plasma concentrations for tenofovir and emtricitabine were 12,500 and >200-fold lower than the respective proposed infant therapeutic doses, and tenofovir was not detected in 94% of infant plasma samples. These data suggest that PrEP can be safely used during breastfeeding with minimal infant drug exposure.

Trial Registration

ClinicalTrials.gov, Identifier: NCT02776748

A Public Health Framework for Legalized Retail Marijuana Based on the US Experience: Avoiding a New Tobacco Industry

PLoS Medicine - Ma, 27/09/2016 - 23:00

by Rachel Ann Barry, Stanton Glantz

Rachel Barry and Stanton Glantz argue that a public health framework that prioritizes public health over business interests should be used by US states and countries that legalize retail marijuana.

Plastic flower blooms thanks to its own internal molecular clock

New Scientist - Ma, 27/09/2016 - 17:00
Shape-shifting putty that can morph at a given time without an external trigger may be useful for creating medical implants that transform inside the body

No, NASA hasn’t changed the zodiac signs or added a new one

New Scientist - Ma, 27/09/2016 - 16:34
Astrology fans should realise that the star signs they love have long been out of date, as NASA and astronomers occasionally point out, says Phil Plait

Exclusive: World’s first baby born with new “3 parent” technique

New Scientist - Ma, 27/09/2016 - 16:04
A five-month-old boy is the first baby to be born using a new version of a controversial technique that uses DNA from three people

Swarm of voracious comb jellies threatens fish off Italian coast

New Scientist - Ma, 27/09/2016 - 11:57
The notorious sea creature shipped around by ballast waters devastated Black Sea fisheries in the 1990s. Now it's found a new home off the coast of Italy

Plumes spotted on Europa raise hopes that we can taste its ocean

New Scientist - Lu, 26/09/2016 - 20:17
We've caught Jupiter's icy moon spitting into space a second time - which means it could be easy for a future spacecraft to scoop up a sample and find life

Why tonight’s debate is ‘narcissist’ Trump v ‘liar’ Clinton

New Scientist - Lu, 26/09/2016 - 19:24
How come public perception of the leading US presidential candidates is so strongly shaped by just two words, wonders Christian Miller

Refugee fence and solar plant may wipe out one of rarest mammals

New Scientist - Lu, 26/09/2016 - 19:22
Hungarian conservationists are laboriously relocating Vojvodina blind mole rats as increased border controls and a new power plant threaten its habitat

Brain-eating amoebas hunt brain chemical before they kill you

New Scientist - Lu, 26/09/2016 - 18:45
A deadly amoeba that can infect swimmers seems to be attracted to a common brain chemical – a discovery that could lead to new treatments

Biggest radio telescope on Earth ready to receive alien signals

New Scientist - Lu, 26/09/2016 - 18:44
The 500-metre-wide radio telescope in rural China will let us study galaxies, pulsars and potential alien signals that would be too faint for any other scope

Puffed-up exoplanets inflate with heat from their stars alone

New Scientist - Lu, 26/09/2016 - 18:37
A recently discovered exoplanet suggests that hot Jupiters are bigger than expected because they absorb their host star’s powerful radiation

US set to miss its emissions target under the Paris climate deal

New Scientist - Lu, 26/09/2016 - 17:00
The UN's Paris climate agreement looks likely to come into effect earlier than thought, but the US for one needs to do much more to honour its commitments

Mystery radio bursts may be pulsars bumping into asteroids

New Scientist - Lu, 26/09/2016 - 16:58
Fast radio bursts have had astronomers puzzled for years, now we think they could be made by pulsars playing bumper cars in faraway star systems

World must resist pressure to lift ban on trade in rhino horn

New Scientist - Lu, 26/09/2016 - 13:20
Allowing seized and farmed rhino horn to be traded to fund conservation measures will simply encourage more poaching, says Richard Schiffman

[Editorial] Care and society

The Lancet - Sa, 24/09/2016 - 00:00
Care is a wonderfully rich word that denotes health, emotion, quality, and thoroughness—each one of which contributes to clinical outcomes. Care is the focus of two recent reports about people aged more than 65 years: Families caring for an aging America (National Academies of Science, Engineering, and Medicine, Sept 13) and Social care for older people (King's Fund and Nuffield Trust, Sept 15). Together, these reports address different aspects of the worldwide challenge to provide dignified, compassionate, quality care to older people in an era when population ageing outstrips economic growth.
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