Tag: research

Occurrence of microplastics in raw and treated drinking water

Microplastics: new methods are needed to filter tiny particles from drinking water, 2019

The presence of plastics in aquatic environments is a growing concern across the EU. This study explored the amount of microplastic particles present in raw and treated water at three water-treatment plants in the Czech Republic. While treated water contained fewer particles than raw1 fresh water, the amount found in treated water was not negligible, and largely comprised tiny particles of <10 micrometres (μm) in diameter. Ways to filter microplastics from potable water must be identified and their risk to humans, sources and routes into drinking water determined, say the researchers, Science for Environment Policy reports.

Highlights

  • Microplastics were present in all water samples from different treatment plants.
  • The concentration of microplastics was higher in raw water than in treated water.
  • Particles of 1–10 μm were the most abundant, accounting for up to 95%.
  • Polyethylene terephthalate, polypropylene and polyethylene microplastics prevailed.

Abstract

The study investigates the content of microplastic particles in freshwater and drinking water. Specifically, three water treatment plants (WTPs) supplied by different kinds of water bodies were selected and their raw and treated water was analysed for microplastics (MPs). Microplastics were found in all water samples and their average abundance ranged from 1473 ± 34 to 3605 ± 497 particles L−1 in raw water and from 338 ± 76 to 628 ± 28 particles L−1 in treated water, depending on the WTP. This study is one of very few that determine microplastics down to the size of 1 μm, while MPs smaller than 10 μm were the most plentiful in both raw and treated water samples, accounting for up to 95%. Further, MPs were divided into three categories according to their shape. Fragments clearly prevailed at two of the WTPs and fibres together with fragments predominated at one case. Despite 12 different materials forming the microplastics being identified, the majority of the MPs (>70%) comprised of PET (polyethylene terephthalate), PP (polypropylene) and PE (polyethylene). This study contributes to fill the knowledge gap in the field of emerging microplastic pollution of drinking water and water sources, which is of concern due to the potential exposure of microplastics to humans.

The Myth of Scientific Objectivity

Dr. Terence Kealey during a CrossFit Health event on March 9, 2019

“I think there is a vast myth that scientists are somehow objective and honest.”

~Dr. Terence Kealey~

Kealey is a former vice-chancellor of the University of Buckingham, a professor of clinical biochemistry, a scholar affiliated with the Cato Institute, and author of the book Breakfast Is a Dangerous Meal. During his presentation, he discussed the myth of scientific objectivity, drawing examples widely from history as well as his personal experiences within many of the most reputable scientific institutions.

Video published on 12 Aug 2019. Reference. Full transcript.

Spin in Published Biomedical Literature : A Systematic Review

Medical research publications : how to modify (abstracts) perception of results

Quinn Grundy presents original research that explores the nature and prevalence of spin in the biomedical literature. Video published on 11 Oct 2017. Reference.

Objective
To explore the nature and prevalence of spin in the biomedical literature.

Design
In a systematic review and meta-analysis, we searched MEDLINE, PreMEDLINE, Embase, Scopus, and handsearched reference lists for all articles published between 1946 and 24 November 2016 that included the quantitative measurement of spin in the biomedical literature for at least 1 outcome. Two independent coders extracted data on the characteristics of articles and included studies, methods for assessing spin, and all spin-related results. The data were heterogeneous; results were grouped inductively into outcome-related categories. We had sufficient data to use meta-analysis to analyze the association of industry sponsorship of research with the presence of spin.

Results
We identified 4219 articles after removing duplicates and included 35 articles that investigated spin: clinical trials (23/35, 66%); observational studies (7/35, 20%); diagnostic accuracy studies (2/35, 6%); and systematic reviews and meta-analyses (4/35, 11%), with some articles including multiple study designs. The nature and manifestations of spin varied according to study design. We grouped results into the following categories: prevalence of spin, level of spin, factors associated with spin, and effects of spin on readers’ interpretations. The highest, but also greatest variability in the prevalence of spin was present in trials (median, 57% of main texts containing spin; range, 19%-100% across 16 articles). Source of funding was hypothesized to be a factor associated with spin; however, the meta-analysis found no significant association, possibly owing to the heterogeneity of the 7 included articles.

Conclusions
Spin appears to be common in the biomedical literature, though this varies by study design, with the highest rates found in clinical trials. Spin manifests in diverse ways, which challenged investigators attempting to systematically identify and document instances of spin. Widening the investigation of factors contributing to spin from characteristics of individual authors or studies to the cultures and structures of research that may incentivize or deincentivize spin, would be instructive in developing strategies to mitigate its occurrence. Further research is also needed to assess the impact of spin on readers’ decision making. Editors and peer reviewers should be familiar with the prevalence and manifestations of spin in their area of research to ensure accurate interpretation and dissemination of research.

Identification of Spin in Clinical Studies Evaluating Biomarkers in Ovarian Cancer

Medical research publications : how to modify (abstracts) perception of results

Mona Ghannad presents a systematic review which documents and classifies spin or overinterpretation, as well as facilitators of spin, in recent clinical studies evaluating performance of biomarkers in ovarian cancer. Video published on 11 Oct 2017. Reference.

Objective
The objective of this systematic review was to document and classify spin or overinterpretation, as well as facilitators of spin, in recent clinical studies evaluating performance of biomarkers in ovarian cancer.

Design
We searched PubMed systematically for all studies published in 2015. Studies eligible for inclusion described 1 or more trial designs for identification and/or validation of prognostic, predictive, or diagnostic biomarkers in ovarian cancer. Reviews, animal studies, and cell line studies were excluded. All studies were screened by 2 reviewers. To document and characterize spin, we collected information on the quality of evidence supporting the study conclusions, linking the performance of the marker to outcomes claimed.

Results
In total, 1026 potentially eligible articles were retrieved by our search strategy, and 345 studies met all eligibility criteria and were included. The first 200 studies, when ranked according to publication date, will be included in our final analysis. Data extraction was done by one researcher and validated by a second. Specific information extracted and analyzed on study and journal characteristics, key information on the relevant evidence in methods, and reporting of conclusions claimed for the first 50 studies is provided here. Actual forms of spin and facilitators of spin were identified in studies trying to establish the performance of the discovered biomarker.

Actual forms of spin identified as shown (Table) were:

  1. other purposes of biomarker claimed not investigated (18 of 50 studies [36%]);
  2. incorrect presentation of results (15 of 50 studies [30%]);
  3. mismatch between the biomarker’s intended clinical application and population recruited (11 of 50 studies [22%]);
  4. mismatch between intended aim and conclusion (7 of 50 studies [14%]);
  5. and mismatch between abstract conclusion and results presented in the main text (6 of 50 studies [12%]).

Frequently observed facilitators of spin were:

  1. not clearly prespecifying a formal test of hypothesis (50 of 50 studies [100%]);
  2. not stating sample size calculations (50 of 50 studies [100%]);
  3. not prespecifying a positivity threshold of continuous biomarker (17 of 43 studies [40%]);
  4. not reporting imprecision or statistical test for data shown (ie, confidence intervals, P values) (12 of 50 studies [24%]);
  5. and selective reporting of significant findings between results for primary outcome reported in abstract and results reported in main text (9 of 50 studies [18%]).

Conclusions
Spin was frequently documented in abstracts, results, and conclusions of clinical studies evaluating performance of biomarkers in ovarian cancer. Inflated and selective reporting of biomarker performance may account for a considerable amount of waste in the biomarker discovery process. Strategies to curb exaggerated reporting are needed to improve the quality and credibility of published biomarker studies.

Systematic reviews with financial conflicts of interest linked to favourable conclusions and lower methodological quality

Financial conflicts of interest in systematic reviews: associations with results, conclusions, and methodological quality

Abstract

Background
Financial conflicts of interest in systematic reviews (e.g. funding by drug or device companies or authors’ collaboration with such companies) may impact on how the reviews are conducted and reported.

Objectives
To investigate the degree to which financial conflicts of interest related to drug and device companies are associated with results, conclusions, and methodological quality of systematic reviews.

Search methods
We searched PubMed, Embase, and the Cochrane Methodology Register for studies published up to November 2016. We also read reference lists of included studies, searched grey literature sources, and Web of Science for studies citing the included studies.

Selection criteria
Eligible studies were studies that compared systematic reviews with and without financial conflicts of interest in order to investigate differences in results (estimated treatment effect and frequency of statistically favourable results), frequency of favourable conclusions, or measures of methodological quality of the review (e.g. as evaluated on the Oxman and Guyatt index).

Data collection and analysis
Two review authors independently determined the eligibility of studies, extracted data, and assessed risk of bias. We synthesised the results of each study relevant to each of our outcomes. For meta‐analyses, we used Mantel‐Haenszel random‐effects models to estimate risk ratios (RR) with 95% confidence intervals (CIs), with RR > 1 indicating that systematic reviews with financial conflicts of interest more frequently had statistically favourable results or favourable conclusions, and had lower methodological quality. When a quantitative synthesis was considered not meaningful, results from individual studies were summarised qualitatively.

Main results
Ten studies with a total of 995 systematic reviews of drug studies and 15 systematic reviews of device studies were included. We assessed two studies as low risk of bias and eight as high risk, primarily because of risk of confounding. The estimated treatment effect was not statistically significantly different for systematic reviews with and without financial conflicts of interest (Z‐score: 0.46, P value: 0.64; based on one study of 14 systematic reviews which had a matched design, comparing otherwise similar systematic reviews). We found no statistically significant difference in frequency of statistically favourable results for systematic reviews with and without financial conflicts of interest (RR: 0.84, 95% CI: 0.62 to 1.14; based on one study of 124 systematic reviews). An analysis adjusting for confounding due to methodological quality (i.e. score on the Oxman and Guyatt index) provided a similar result. Systematic reviews with financial conflicts of interest more often had favourable conclusions compared with systematic reviews without (RR: 1.98, 95% CI: 1.26 to 3.11; based on seven studies of 411 systematic reviews). Similar results were found in two studies with a matched design, which therefore had a reduced risk of confounding. Systematic reviews with financial conflicts of interest tended to have lower methodological quality compared with systematic reviews without financial conflicts of interest (RR for 11 dimensions of methodological quality spanned from 1.00 to 1.83). Similar results were found in analyses based on two studies with matched designs.

Authors’ conclusions
Systematic reviews with financial conflicts of interest more often have favourable conclusions and tend to have lower methodological quality than systematic reviews without financial conflicts of interest. However, it is uncertain whether financial conflicts of interest are associated with the results of systematic reviews. We suggest that patients, clinicians, developers of clinical guidelines, and planners of further research could primarily use systematic reviews without financial conflicts of interest. If only systematic reviews with financial conflicts of interest are available, we suggest that users read the review conclusions with skepticism, critically appraise the methods applied, and interpret the review results with caution.

Angell on Big Pharma

Some more truth about the pharmaceutical companies

Do pharmaceutical companies corrupt academic research and the clinical trial process ? You bet.

Dr Marcia Angell of Harvard Medical School and the author of The Truth About the Drug Companies talks with EconTalk host Russ Roberts about the impact of pharmaceutical companies on academic research, clinical trials and the political process. Angell argues that the large pharmaceutical companies produce little or no innovation and use their political power to exploit consumers and taxpayers. Reference.

New medicine drugs : No evidence of added benefit for most

New drugs : where did we go wrong and what can we do better ?

More than half of new drugs in Germany lack proof of added benefit over existing treatments. International drug development processes and policies are responsible and must be reformed, the BMJ reports.

“Medicines regulators around the world are pursuing a strategy aimed at accelerating the development and approval of drugs. These approaches are based on the assumption that faster access to new drugs benefits patients. The rhetoric of novelty and innovation creates an assumption that new products are better than existing ones.

But although gaps in the therapeutic armamentarium undoubtedly exist, research covering drug approvals since the 1970s suggests only a limited number of new drugs provide real advances over existing drugs. Most studies put the proportion of true innovation at under 15%, with no clear improvement over time.”

… continue reading on The BMJ, 10 July 2019.

Medical research publications : how to modify (abstracts) perception of negative (or non-significant) results into positive ones

Evaluation of Spin in the Abstracts of Emergency Medicine Randomized Controlled Trials

Spin is common (>40%) in emergency medicine randomized controlled trials…

May 2019 Study objective

We aim to investigate spin in emergency medicine abstracts, using a sample of randomized controlled trials from high-impact-factor journals with statistically nonsignificant primary endpoints.

Methods

This study investigated spin in abstracts of emergency medicine randomized controlled trials from emergency medicine literature, with studies from 2013 to 2017 from the top 5 emergency medicine journals and general medical journals. Investigators screened records for inclusion and extracted data for spin. We considered evidence of spin if trial authors focused on statistically significant results, interpreted statistically nonsignificant results as equivalent or noninferior, used favorable rhetoric in the interpretation of nonsignificant results, or claimed benefit of an intervention despite statistically nonsignificant results.

Results

Of 772 abstracts screened, 114 randomized controlled trials reported statistically nonsignificant primary endpoints. Spin was found in 50 of 114 abstracts (44.3%). Industry-funded trials were more likely to have evidence of spin in the abstract (unadjusted odds ratio 3.4; 95% confidence interval 1.1 to 11.9). In the abstracts’ results, evidence of spin was most often due to authors’ emphasizing a statistically significant subgroup analysis (n=9). In the abstracts’ conclusions, spin was most often due to authors’ claiming they accomplished an objective that was not a prespecified endpoint (n=14).

Conclusion

Spin was prevalent in the selected randomized controlled trial, emergency medicine abstracts. Authors most commonly incorporated spin into their reports by focusing on statistically significant results for secondary outcomes or subgroup analyses when the primary outcome was statistically nonsignificant. Spin was more common in studies that had some component of industry funding.

A New Laser Cytophone Device Able to Find and Destroy Cancer Cells in the Blood ?

In vivo liquid biopsy using Cytophone platform for photoacoustic detection of circulating tumor cells in patients with melanoma

Cancer cells can spread to other parts of the body through the blood. And now, researchers have developed a new kind of laser that can find and zap those tumor cells from the outside of the skin, LiveScience reports, medicalxpress reports and medicaldaily reports.

Abstract

Most cancer deaths arise from metastases as a result of circulating tumor cells (CTCs) spreading from the primary tumor to vital organs. Despite progress in cancer prognosis, the role of CTCs in early disease diagnosis is unclear because of the low sensitivity of CTC assays. We demonstrate the high sensitivity of the Cytophone technology using an in vivo photoacoustic flow cytometry platform with a high pulse rate laser and focused ultrasound transducers for label-free detection of melanin-bearing CTCs in patients with melanoma. The transcutaneous delivery of laser pulses via intact skin to a blood vessel results in the generation of acoustic waves from CTCs, which are amplified by vapor nanobubbles around intrinsic melanin nanoclusters. The time-resolved detection of acoustic waves using fast signal processing algorithms makes photoacoustic data tolerant to skin pigmentation and motion. No CTC-associated signals within established thresholds were identified in 19 healthy volunteers, but 27 of 28 patients with melanoma displayed signals consistent with single, clustered, and likely rolling CTCs. The detection limit ranged down to 1 CTC/liter of blood, which is ~1000 times better than in preexisting assays. The Cytophone could detect individual CTCs at a concentration of ≥1 CTC/ml in 20 s and could also identify clots and CTC-clot emboli. The in vivo results were verified with six ex vivo methods. These data suggest the potential of in vivo blood testing with the Cytophone for early melanoma screening, assessment of disease recurrence, and monitoring of the physical destruction of CTCs through real-time CTC counting.

Environmental Chemicals and Autism

A Scoping Review of the Human and Animal Research, 2019

The Endocrine Disruption Exchange newest scoping review finds that 152 environmental chemicals have been investigated in humans or animals for their association with autism. TEDX highlight the need for systematic review of lead, PCBs, and chlorpyrifos.

Abstract

Background
Estimates of autism prevalence have increased dramatically over the past two decades. Evidence suggests environmental factors may contribute to the etiology of the disorder.

Objectives
This scoping review aimed to identify and categorize primary research and reviews on the association between prenatal and early postnatal exposure to environmental chemicals and the development of autism in epidemiological studies and rodent models of autism.

Methods
PubMed was searched through 8 February 2018. Included studies assessed exposure to environmental chemicals prior to 2 months of age in humans or 14 d in rodents. Rodent studies were considered relevant if they included at least one measurement of reciprocal social communicative behavior or repetitive and stereotyped behavior. Study details are presented in interactive displays using Tableau Public.

Results
The search returned 21,603 unique studies, of which 54 epidemiological studies, 46 experimental rodent studies, and 50 reviews were deemed relevant, covering 152 chemical exposures. The most frequently studied exposures in humans were particulate matter (n=14), mercury (n=14), nonspecific air pollution (n=10), and lead (n=10). In rodent studies, the most frequently studied exposures were chlorpyrifos (n=9), mercury (n=6), and lead (n=4).

Discussion
Although research is growing rapidly, wide variability exists in study design and conduct, exposures investigated, and outcomes assessed. Conclusions focus on recommendations to guide development of best practices in epidemiology and toxicology, including greater harmonization across these fields of research to more quickly and efficiently identify chemicals of concern. In particular, we recommend chlorpyrifos, lead, and polychlorinated biphenyls (PCBs) be systematically reviewed in order to assess their relationship with the development of autism. There is a pressing need to move forward quickly and efficiently to understand environmental influences on autism in order to answer current regulatory questions and inform treatment and prevention efforts.