Does case misclassification threaten the validity of studies investigating the relationship between neck manipulation and vertebral artery dissection stroke? No

Background: The purported relationship between cervical manipulative therapy (CMT) and stroke related to vertebral artery dissection (VAD) has been debated for several decades. A large number of publications, from case reports to case–control studies, have investigated this relationship. A recent article suggested that case misclassification in the case–control studies on this topic resulted in biased odds ratios in those studies. Discussion: Given its rarity, the best epidemiologic research design for investigating the relationship between CMT and VAD is the case–control study. The addition of a case-crossover aspect further strengthens the scientific rigor of such studies by reducing bias. The most recent studies investigating the relationship between CMT and VAD indicate that the relationship is not causal. In fact, a comparable relationship between vertebral artery-related stroke and visits to a primary care physician has been observed. The statistical association between visits to chiropractors and VAD can best be explained as resulting from a patient with early manifestation of VAD (neck pain with or without headache) seeking the services of a chiropractor for relief of this pain. Sometime after the visit the patient experiences VAD-related stroke that would have occurred regardless of the care received. This explanation has been challenged by a recent article putting forth the argument that case misclassification is likely to have biased the odds ratios of the case–control studies that have investigated the association between CMT and vertebral artery related stroke. The challenge particularly focused on one of the case–control studies, which had concluded that the association between CMT and vertebral artery related stroke was not causal. It was suggested by the authors of the recent article that misclassification led to an underestimation of risk. We argue that the information presented in that article does not support the authors’ claim for a variety of reasons, including the fact that the assumptions upon which their analysis is based lack substantiation and the fact that any possible misclassification would not have changed the conclusion of the study in question. Conclusion: Current evidence does not support the notion that misclassification threatens the validity of recent case–control studies investigating the relationship between CMT and VAD. Hence, the recent re-analysis cannot refute the conclusion from previous studies that CMT is not a cause of VAD.https://doi.org/10.1186/s12998-016-0124-

Abundance and biogeography of picoprasinophyte ecotypes and other phytoplankton in the eastern North Pacific Ocean

Eukaryotic algae within the picoplankton size class (< 2 μmin diameter) are important marine primary producers, but their spatial and ecological distributions are not well characterized. Here, we studied three picoeukaryotic prasinophyte genera and their cyanobacterial counterparts, Prochlorococcus and Synechococcus, during two cruises along a North Pacific transect characterized by different ecological regimes. Picoeukaryotes and Synechococcus reached maximum abundances of 1.44 × 105 and 3.37 × 105 cells · ml-1, respectively, in mesotrophic waters, while Prochlorococcus reached 1.95 × 105 cells · ml-1 in the oligotrophic ocean. Of the picoeukaryotes, Bathycoccus was present at all stations in both cruises, reaching 21,368±327 18S rRNA gene copies · ml-1. Micromonas and Ostreococcus clade OI were detected only in mesotrophic and coastal waters and Ostreococcus clade OII only in the oligotrophic ocean. To resolve proposed Bathycoccus ecotypes, we established genetic distances for 1,104 marker genes using targeted metagenomes and the Bathycoccus prasinos genome. The analysis was anchored in comparative genome analysis of three Ostreococcus species for which physiological and environmental data are available to facilitate data interpretation. We established that two Bathycoccus ecotypes exist, named here BI (represented by coastal isolate Bathycoccus prasinos) and BII. These share 82±6 nucleotide identity across homologs, while the Ostreococcus spp. share 75±8. We developed and applied an analysis of ecomarkers to metatranscriptomes sequenced here and published -omics data from the same region. The results indicated that the Bathycoccus ecotypes cooccur more often than Ostreococcus clades OI and OII do. Exploratory analyses of relative transcript abundances suggest that Bathycoccus NRT2.1 and AMT2.2 are high-affinity NO3 - and low-affinity NH4 + transporters, respectively, with close homologs in multiple picoprasinophytes. Additionally, in the open ocean, where dissolved iron concentrations were low (0.08 nM), there appeared to be a shift to the use of nickel superoxide dismutases (SODs) from Mn/Fe/Cu SODs closer inshore. Our study documents the distribution of picophytoplankton along a North Pacific ecological gradient and offers new concepts and techniques for investigating their biogeography. © 2016, American Society for Microbiology. All Rights Reserved

A united statement of the global chiropractic research community against the pseudoscientific claim that chiropractic care boosts immunity.

BACKGROUND: In the midst of the coronavirus pandemic, the International Chiropractors Association (ICA) posted reports claiming that chiropractic care can impact the immune system. These claims clash with recommendations from the World Health Organization and World Federation of Chiropractic. We discuss the scientific validity of the claims made in these ICA reports. MAIN BODY: We reviewed the two reports posted by the ICA on their website on March 20 and March 28, 2020. We explored the method used to develop the claim that chiropractic adjustments impact the immune system and discuss the scientific merit of that claim. We provide a response to the ICA reports and explain why this claim lacks scientific credibility and is dangerous to the public. More than 150 researchers from 11 countries reviewed and endorsed our response. CONCLUSION: In their reports, the ICA provided no valid clinical scientific evidence that chiropractic care can impact the immune system. We call on regulatory authorities and professional leaders to take robust political and regulatory action against those claiming that chiropractic adjustments have a clinical impact on the immune system

Using Stable Isotope Analysis to Understand the Migration and Trophic Ecology of Northeastern Pacific White Sharks (<em>Carcharodon carcharias</em>)

<div><p>The white shark (<em>Carcharodon carcharias</em>) is a wide-ranging apex predator in the northeastern Pacific (NEP). Electronic tagging has demonstrated that white sharks exhibit a regular migratory pattern, occurring at coastal sites during the late summer, autumn and early winter and moving offshore to oceanic habitats during the remainder of the year, although the purpose of these migrations remains unclear. The purpose of this study was to use stable isotope analysis (SIA) to provide insight into the trophic ecology and migratory behaviors of white sharks in the NEP. Between 2006 and 2009, 53 white sharks were biopsied in central California to obtain dermal and muscle tissues, which were analyzed for stable isotope values of carbon (δ¹³C) and nitrogen (δ¹⁵N). We developed a mixing model that directly incorporates movement data and tissue incorporation (turnover) rates to better estimate the relative importance of different focal areas to white shark diet and elucidate their migratory behavior. Mixing model results for muscle showed a relatively equal dietary contribution from coastal and offshore regions, indicating that white sharks forage in both areas. However, model results indicated that sharks foraged at a higher relative rate in coastal habitats. There was a negative relationship between shark length and muscle δ¹³C and δ¹⁵N values, which may indicate ontogenetic changes in habitat use related to onset of maturity. The isotopic composition of dermal tissue was consistent with a more rapid incorporation rate than muscle and may represent more recent foraging. Low offshore consumption rates suggest that it is unlikely that foraging is the primary purpose of the offshore migrations. These results demonstrate how SIA can provide insight into the trophic ecology and migratory behavior of marine predators, especially when coupled with electronic tagging data.</p> </div

Rate of consumption in offshore focal areas (PEL: Pelagic, HI: Hawaii) relative to California (CA) estimated using the spatially explicit Bayesian mixing model.

<p>Results show posterior model estimates (median, interquartile range and max/min values). The green dashed line designates the relative consumption rate in the California focal area. Consumption rate is estimated using three different tissue incorporation rates for both offshore focal areas (SB: juvenile sandbar shark, BA: allometrically scaled bird, FA: allometrically scaled fish, see text for details).</p

Relationship between white shark length (TL) and δ¹³C and δ¹⁵N of white shark muscle.

<p>The two ellipses contain the δ¹³C and δ¹⁵N values of two of the smallest sharks that had the highest δ¹³C and δ¹⁵N values.</p

Overall contribution of different focal areas to white shark muscle tissue using different tissue incorporation rates.

<p>Estimates incorporate tissue incorporation rate, satellite tag data, and consumption rate. Median and 95% credible intervals are presented.</p

δ¹³C and δ ¹⁵N of white shark muscle and dermal tissue.

<p>δ¹³C and δ ¹⁵N of white shark muscle and dermal tissue.</p

Estimated δ¹³C and δ ¹⁵N values of white shark focal areas.

<p>Estimated δ¹³C and δ ¹⁵N values of white shark focal areas.</p

δ¹³C and δ¹⁵N values of white shark tissues and potential prey items from different focal areas.

<p>Regions and shark tissues are designated with different symbols and colors. For regions, smaller symbols show mean (SD) isotopic values of individual species and larger symbols indicating mean regional average (SD). 4a: δ¹³C and δ¹⁵N values for different prey, regions and white sharks tissues. Individual species are labeled according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030492#pone-0030492-t001" target="_blank">Table 1</a>. 4b: Mixing polygon used to estimate contribution of different regions to white shark tissue. Regional (and prey) values are adjusted to account for discrimination factor (Kim et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030492#pone.0030492-Kim2" target="_blank">[67]</a>). Error in discrimination factors was propagated into error of mean regional values. Muscle (est) is the predicted mean stable isotope composition of white shark muscle if sharks foraged at the same rate in the different regions. Dermis (corr) is the mean dermal stable isotope composition adjusted to resemble muscle by accounting for differences in discrimination factors between the tissues; the adjustment is based on Hussey et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030492#pone.0030492-Hussey1" target="_blank">[90]</a>. Note that the closer the tissue values are to source (region) values, the higher the contribution of that source to the tissue.</p