Riviste scientifiche

Finding Nemo is real: Clownfish make epic sea journeys

New Scientist - Me, 17/09/2014 - 20:00
Clownfish travel hundreds of kilometres, but it is the larvae rather than the adults that migrate






China clamps down on dirtiest coal to curb pollution

New Scientist - Me, 17/09/2014 - 19:30
The largest consumer of coal in the world has announced radical restrictions on coal imports and its domestic transport and use






Artificial sweeteners linked to glucose intolerance

New Scientist - Me, 17/09/2014 - 19:00
Aspartame, saccharin and sucralose made mice glucose intolerant – a risk for diabetes – probably by altering their gut flora. Is it happening in humans too?






Lasers slim down on stopped-light diet

New Scientist - Me, 17/09/2014 - 19:00
A new kind of laser that powers up by freezing light in its tracks could lead to computers that run on photons instead of electrons






Today on New Scientist

New Scientist - Me, 17/09/2014 - 18:30
All the latest on newscientist.com: preferred vs promoted in digital media, Jaws in Cornwall, psychology experiments we'd ban now and more






Record sea ice around Antarctica due to global warming

New Scientist - Me, 17/09/2014 - 18:30
The extent of Antarctica's sea ice has hit yet another record high, and counter-intuitively global warming is responsible






World closes in on goal of halving hunger by 2015

New Scientist - Me, 17/09/2014 - 17:57
The number of people without enough to eat has fallen rapidly over the past 25 years, but sub-Saharan Africa and parts of Asia are still struggling






Shockers: Psychology experiments that we'd ban now

New Scientist - Me, 17/09/2014 - 17:10
You can learn a lot about people if you mess with their minds. Here are four infamous experiments in which psychologists gave in to unethical temptations






Boeing and SpaceX bag NASA's $6.8bn space taxi prize

New Scientist - Me, 17/09/2014 - 15:40
NASA has announced that two private companies, Boeing and SpaceX, will start launching astronauts to the International Space Station in 2017






Leaky wells, not fracking, polluted US drinking water

New Scientist - Me, 17/09/2014 - 13:57
The act of fracking is probably not contaminating US drinking water – the real problem is leaks from the wells that bring natural gas to the surface






Stem cells used in landmark therapy for failing sight

New Scientist - Me, 17/09/2014 - 12:03
A Japanese woman with macular degeneration is the first person to be treated with induced pluripotent stem cells, made from her own skin






No, Jaws is not lurking off the Cornish coast

New Scientist - Me, 17/09/2014 - 09:00
Scaremongering claims of a great white shark in UK waters could have been easily avoided, says shark conservation biologist David Shiffman






Simple urine test detects cervical cancer virus

New Scientist - Me, 17/09/2014 - 00:30
It is not as accurate as sampling HPV DNA from the cervix itself, but the test might benefit women who are too scared to have a conventional smear test






Genetic Predisposition to Increased Blood Cholesterol and Triglyceride Lipid Levels and Risk of Alzheimer Disease: A Mendelian Randomization Analysis

PLoS Medicine - Ma, 16/09/2014 - 23:00

by Petroula Proitsi, Michelle K. Lupton, Latha Velayudhan, Stephen Newhouse, Isabella Fogh, Magda Tsolaki, Makrina Daniilidou, Megan Pritchard, Iwona Kloszewska, Hilkka Soininen, Patrizia Mecocci, Bruno Vellas, for the Alzheimer's Disease Neuroimaging Initiative , Julie Williams, for the GERAD1 Consortium , Robert Stewart, Pak Sham, Simon Lovestone, John F. Powell

Background

Although altered lipid metabolism has been extensively implicated in the pathogenesis of Alzheimer disease (AD) through cell biological, epidemiological, and genetic studies, the molecular mechanisms linking cholesterol and AD pathology are still not well understood and contradictory results have been reported. We have used a Mendelian randomization approach to dissect the causal nature of the association between circulating lipid levels and late onset AD (LOAD) and test the hypothesis that genetically raised lipid levels increase the risk of LOAD.

Methods and Findings

We included 3,914 patients with LOAD, 1,675 older individuals without LOAD, and 4,989 individuals from the general population from six genome wide studies drawn from a white population (total n = 10,578). We constructed weighted genotype risk scores (GRSs) for four blood lipid phenotypes (high-density lipoprotein cholesterol [HDL-c], low-density lipoprotein cholesterol [LDL-c], triglycerides, and total cholesterol) using well-established SNPs in 157 loci for blood lipids reported by Willer and colleagues (2013). Both full GRSs using all SNPs associated with each trait at p<5×10−8 and trait specific scores using SNPs associated exclusively with each trait at p<5×10−8 were developed. We used logistic regression to investigate whether the GRSs were associated with LOAD in each study and results were combined together by meta-analysis. We found no association between any of the full GRSs and LOAD (meta-analysis results: odds ratio [OR] = 1.005, 95% CI 0.82–1.24, p = 0.962 per 1 unit increase in HDL-c; OR = 0.901, 95% CI 0.65–1.25, p = 0.530 per 1 unit increase in LDL-c; OR = 1.104, 95% CI 0.89–1.37, p = 0.362 per 1 unit increase in triglycerides; and OR = 0.954, 95% CI 0.76–1.21, p = 0.688 per 1 unit increase in total cholesterol). Results for the trait specific scores were similar; however, the trait specific scores explained much smaller phenotypic variance.

Conclusions

Genetic predisposition to increased blood cholesterol and triglyceride lipid levels is not associated with elevated LOAD risk. The observed epidemiological associations between abnormal lipid levels and LOAD risk could therefore be attributed to the result of biological pleiotropy or could be secondary to LOAD. Limitations of this study include the small proportion of lipid variance explained by the GRS, biases in case-control ascertainment, and the limitations implicit to Mendelian randomization studies. Future studies should focus on larger LOAD datasets with longitudinal sampled peripheral lipid measures and other markers of lipid metabolism, which have been shown to be altered in LOAD.Please see later in the article for the Editors' Summary

WHO Essential Medicines Policies and Use in Developing and Transitional Countries: An Analysis of Reported Policy Implementation and Medicines Use Surveys

PLoS Medicine - Ma, 16/09/2014 - 23:00

by Kathleen Anne Holloway, David Henry

Background

Suboptimal medicine use is a global public health problem. For 35 years the World Health Organization (WHO) has promoted essential medicines policies to improve quality use of medicines (QUM), but evidence of their effectiveness is lacking, and uptake by countries remains low. Our objective was to determine whether WHO essential medicines policies are associated with better QUM.

Methods and Findings

We compared results from independently conducted medicines use surveys in countries that did versus did not report implementation of WHO essential medicines policies. We extracted survey data on ten validated QUM indicators and 36 self-reported policy implementation variables from WHO databases for 2002–2008. We calculated the average difference (as percent) for the QUM indicators between countries reporting versus not reporting implementation of specific policies. Policies associated with positive effects were included in a regression of a composite QUM score on total numbers of implemented policies. Data were available for 56 countries. Twenty-seven policies were associated with better use of at least two percentage points. Eighteen policies were associated with significantly better use (unadjusted p<0.05), of which four were associated with positive differences of 10% or more: undergraduate training of doctors in standard treatment guidelines, undergraduate training of nurses in standard treatment guidelines, the ministry of health having a unit promoting rational use of medicines, and provision of essential medicines free at point of care to all patients. In regression analyses national wealth was positively associated with the composite QUM score and the number of policies reported as being implemented in that country. There was a positive correlation between the number of policies (out of the 27 policies with an effect size of 2% or more) that countries reported implementing and the composite QUM score (r = 0.39, 95% CI 0.14 to 0.59, p = 0.003). This correlation weakened but remained significant after inclusion of national wealth in multiple linear regression analyses. Multiple policies were more strongly associated with the QUM score in the 28 countries with gross national income per capita below the median value (US$2,333) (r = 0.43, 95% CI 0.06 to 0.69, p = 0.023) than in the 28 countries with values above the median (r = 0.22, 95% CI −0.15 to 0.56, p = 0.261). The main limitations of the study are the reliance on self-report of policy implementation and measures of medicine use from small surveys. While the data can be used to explore the association of essential medicines policies with medicine use, they cannot be used to compare or benchmark individual country performance.

Conclusions

WHO essential medicines policies are associated with improved QUM, particularly in low-income countries.Please see later in the article for the Editors' Summary

The Clinical and Economic Impact of Point-of-Care CD4 Testing in Mozambique and Other Resource-Limited Settings: A Cost-Effectiveness Analysis

PLoS Medicine - Ma, 16/09/2014 - 23:00

by Emily P. Hyle, Ilesh V. Jani, Jonathan Lehe, Amanda E. Su, Robin Wood, Jorge Quevedo, Elena Losina, Ingrid V. Bassett, Pamela P. Pei, A. David Paltiel, Stephen Resch, Kenneth A. Freedberg, Trevor Peter, Rochelle P. Walensky

Background

Point-of-care CD4 tests at HIV diagnosis could improve linkage to care in resource-limited settings. Our objective is to evaluate the clinical and economic impact of point-of-care CD4 tests compared to laboratory-based tests in Mozambique.

Methods and Findings

We use a validated model of HIV testing, linkage, and treatment (CEPAC-International) to examine two strategies of immunological staging in Mozambique: (1) laboratory-based CD4 testing (LAB-CD4) and (2) point-of-care CD4 testing (POC-CD4). Model outcomes include 5-y survival, life expectancy, lifetime costs, and incremental cost-effectiveness ratios (ICERs). Input parameters include linkage to care (LAB-CD4, 34%; POC-CD4, 61%), probability of correctly detecting antiretroviral therapy (ART) eligibility (sensitivity: LAB-CD4, 100%; POC-CD4, 90%) or ART ineligibility (specificity: LAB-CD4, 100%; POC-CD4, 85%), and test cost (LAB-CD4, US$10; POC-CD4, US$24). In sensitivity analyses, we vary POC-CD4-specific parameters, as well as cohort and setting parameters to reflect a range of scenarios in sub-Saharan Africa. We consider ICERs less than three times the per capita gross domestic product in Mozambique (US$570) to be cost-effective, and ICERs less than one times the per capita gross domestic product in Mozambique to be very cost-effective. Projected 5-y survival in HIV-infected persons with LAB-CD4 is 60.9% (95% CI, 60.9%–61.0%), increasing to 65.0% (95% CI, 64.9%–65.1%) with POC-CD4. Discounted life expectancy and per person lifetime costs with LAB-CD4 are 9.6 y (95% CI, 9.6–9.6 y) and US$2,440 (95% CI, US$2,440–US$2,450) and increase with POC-CD4 to 10.3 y (95% CI, 10.3–10.3 y) and US$2,800 (95% CI, US$2,790–US$2,800); the ICER of POC-CD4 compared to LAB-CD4 is US$500/year of life saved (YLS) (95% CI, US$480–US$520/YLS). POC-CD4 improves clinical outcomes and remains near the very cost-effective threshold in sensitivity analyses, even if point-of-care CD4 tests have lower sensitivity/specificity and higher cost than published values. In other resource-limited settings with fewer opportunities to access care, POC-CD4 has a greater impact on clinical outcomes and remains cost-effective compared to LAB-CD4. Limitations of the analysis include the uncertainty around input parameters, which is examined in sensitivity analyses. The potential added benefits due to decreased transmission are excluded; their inclusion would likely further increase the value of POC-CD4 compared to LAB-CD4.

Conclusions

POC-CD4 at the time of HIV diagnosis could improve survival and be cost-effective compared to LAB-CD4 in Mozambique, if it improves linkage to care. POC-CD4 could have the greatest impact on mortality in settings where resources for HIV testing and linkage are most limited.Please see later in the article for the Editors' Summary

The war for our attention in a land of infinite choice

New Scientist - Ma, 16/09/2014 - 20:00
With more content than ever before, its hard to extract what's preferred from what's promoted. Two books explore the effect digital media has on us






Today on New Scientist

New Scientist - Ma, 16/09/2014 - 18:30
All the latest on newscientist.com: Socrates among the psychopaths, putting a "language gene" into mice, students saved by stress-detecting app and more






Failing students saved by stress-detecting app

New Scientist - Ma, 16/09/2014 - 14:00
Smartphone sensors can record students' stress, depression and loneliness, and compare them to academic performance






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