75 research outputs found
Anisotropy links cell shapes to tissue flow during convergent extension
Within developing embryos, tissues flow and reorganize dramatically on
timescales as short as minutes. This includes epithelial tissues, which often
narrow and elongate in convergent extension movements due to anisotropies in
external forces or in internal cell-generated forces. However, the mechanisms
that allow or prevent tissue reorganization, especially in the presence of
strongly anisotropic forces, remain unclear. We study this question in the
converging and extending Drosophila germband epithelium, which displays planar
polarized myosin II and experiences anisotropic forces from neighboring
tissues, and we show that in contrast to isotropic tissues, cell shape alone is
not sufficient to predict the onset of rapid cell rearrangement. From
theoretical considerations and vertex model simulations, we predict that in
anisotropic tissues two experimentally accessible metrics of cell patterns, the
cell shape index and a cell alignment index, are required to determine whether
an anisotropic tissue is in a solid-like or fluid-like state. We show that
changes in cell shape and alignment over time in the Drosophila germband
predict the onset of rapid cell rearrangement in both wild-type and snail twist
mutant embryos, where our theoretical prediction is further improved when we
also account for cell packing disorder. These findings suggest that convergent
extension is associated with a transition to more fluid-like tissue behavior,
which may help accommodate tissue shape changes during rapid developmental
events
Resuming elective hip and knee arthroplasty after the first phase of the SARS-CoV-2 pandemic: the European Hip Society and European Knee Associates recommendations
The Covid-19 pandemic has disrupted health care systems all over the world. Elective surgical procedures have
been postponed and/or cancelled. Consensus is, therefore, required related to the factors that need to be in place before elective
surgery, including hip and knee replacement surgery, which is restarted. Entirely new pathways and protocols need to
be worked out.
Methods A panel of experts from the European Hip Society and European Knee Association have agreed to a consensus
statement on how to reintroduce elective arthroplasty surgery safely. The recommendations are based on the best available
evidence and have been validated in a separate survey.
Results The guidelines are based on five themes: modification and/or reorganisation of hospital wards. Restrictions on
orthopaedic wards and in operation suite(s). Additional disinfection of the environment. The role of ultra-clean operation
theatres. Personal protective equipment enhancement.
Conclusion Apart from the following national and local guidance, protocols need to be put in place in the patient pathway
for primary arthroplasty to allow for a safe retur
Recommendations for resuming elective hip and knee arthroplasty in the setting of the SARS‑CoV‑2 pandemic: the European Hip Society and European Knee Associates Survey of Members
The COVID-19 pandemic has disrupted the health care system around the entire globe. A consensus is needed
about resuming total hip and knee procedures. The European Hip Society (EHS) and the European Knee Association (EKA)
formed a panel of experts that have produced a consensus statement on how the safe re-introduction of elective hip and knee
arthroplasty should be undertaken.
Methods A prospective online survey was done among members of EHS and EKA. The survey consisted of 27 questions.
It includes basic information on demographics and details the participant’s agreement with each recommendation. The
participant could choose among three options (agree, disagree, abstain). Recommendations focussed on pre-operative, perioperative, and post-operative handling of patients and precautions.
Results A total of 681 arthroplasty surgeons participated in the survey, with 479 fully completing the survey. The participants were from 44 countries and 6 continents. Apart from adhering to National and Local Guidelines, the recommendations
concerned how to make elective arthroplasty safe for patients and staf.
Conclusion The survey has shown good-to-excellent agreement of the participants with regards to the statements made in
the recommendations for the safe return to elective arthroplasty following the frst wave of the COVID-19 pandemi
2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease
The recommendations listed in this document are, whenever possible, evidence based. An extensive evidence review was conducted as the document was compiled through December 2008. Repeated literature searches were performed by the guideline development staff and writing committee members as new issues were considered. New clinical trials published in peer-reviewed journals and articles through December 2011 were also reviewed and incorporated when relevant. Furthermore, because of the extended development time period for this guideline, peer review comments indicated that the sections focused on imaging technologies required additional updating, which occurred during 2011. Therefore, the evidence review for the imaging sections includes published literature through December 2011
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