Background Three-dimensional (3D) printing is becoming increasingly important in medicine and especially in surgery. The aim of the present work was to identify the advantages and disadvantages of 3D ...printing applied in surgery. Methods We conducted a systematic review of articles on 3D printing applications in surgery published between 2005 and 2015 and identified using a PubMed and EMBASE search. Studies dealing with bioprinting, dentistry, and limb prosthesis or those not conducted in a hospital setting were excluded. Results A total of 158 studies met the inclusion criteria. Three-dimensional printing was used to produce anatomic models (n = 113, 71.5%), surgical guides and templates (n = 40, 25.3%), implants (n = 15, 9.5%) and molds (n = 10, 6.3%), and primarily in maxillofacial (n = 79, 50.0%) and orthopedic (n = 39, 24.7%) operations. The main advantages reported were the possibilities for preoperative planning (n = 77, 48.7%), the accuracy of the process used (n = 53, 33.5%), and the time saved in the operating room (n = 52, 32.9%); 34 studies (21.5%) stressed that the accuracy was not satisfactory. The time needed to prepare the object (n = 31, 19.6%) and the additional costs (n = 30, 19.0%) were also seen as important limitations for routine use of 3D printing. Conclusion The additional cost and the time needed to produce devices by current 3D technology still limit its widespread use in hospitals. The development of guidelines to improve the reporting of experience with 3D printing in surgery is highly desirable.
The centrosome is the main microtubule‐organizing centre. It also organizes a local network of actin filaments. However, the precise function of the actin network at the centrosome is not well ...understood. Here, we show that increasing densities of actin filaments at the centrosome of lymphocytes are correlated with reduced amounts of microtubules. Furthermore, lymphocyte activation resulted in disassembly of centrosomal actin and an increase in microtubule number. To further investigate the direct crosstalk between actin and microtubules at the centrosome, we performed in vitro reconstitution assays based on (i) purified centrosomes and (ii) on the co‐micropatterning of microtubule seeds and actin filaments. These two assays demonstrated that actin filaments constitute a physical barrier blocking elongation of nascent microtubules. Finally, we showed that cell adhesion and cell spreading lead to lower densities of centrosomal actin, thus resulting in higher microtubule growth. We therefore propose a novel mechanism, by which the number of centrosomal microtubules is regulated by cell adhesion and actin‐network architecture.
Synopsis
Centrosomes, the main interphase microtubule‐organizing centers of the cell, also nucleate local actin filament networks, which are now found to form a physical barrier blocking microtubule elongation.
Activation of B lymphocytes is associated with reduction of centrosomal actin and increase in the number of microtubules.
The amount of centrosomal actin is negatively correlated to the amount of microtubules.
In vitro reconstitutions show negative correlation between the amount of centrosomal actin and the number of microtubules.
Cell spreading proportionally affects the amount of centrosomal actin and the number of centrosomal microtubules.
Increasing density of F‐actin nucleating from the main interphase microtubule‐organizing center creates a physical barrier for nascent microtubules in lymphocytes and in vitro.
An important channel of cell-to-cell communication is direct contact. The immune synapse is a paradigmatic example of such type of interaction: it forms upon engagement of antigen receptors in ...lymphocytes by antigen-presenting cells and allows the local exchange of molecules and information. Although mechanics has been shown to play an important role in this process, how forces organize and impact on synapse function is unknown. We find that mechanical forces are spatio-temporally patterned at the immune synapse: global pulsatile myosin II-driven tangential forces are observed at the synapse periphery while localised forces generated by invadosome-like F-actin protrusions are detected at its centre. Noticeably, we observe that these force-producing actin protrusions constitute the main site of antigen extraction and endocytosis and require myosin II contractility to form. The interplay between global and local forces dictated by the organization of the actomyosin cytoskeleton therefore controls endocytosis at the immune synapse.
Immune synapse formation is a key step for lymphocyte activation. In B lymphocytes, the immune synapse controls the production of high-affinity antibodies, thereby defining the efficiency of humoral ...immune responses. While the key roles played by both the actin and microtubule cytoskeletons in the formation and function of the immune synapse have become increasingly clear, how the different events involved in synapse formation are coordinated in space and time by actin–microtubule interactions is not understood. Using a microfluidic pairing device, we studied with unprecedented resolution the dynamics of the various events leading to immune synapse formation and maintenance in murine B cells. Our results identify two groups of events, local and global, dominated by actin and microtubules dynamics, respectively. They further highlight an unexpected role for microtubules and the GEF-H1-RhoA axis in restricting F-actin polymerization at the lymphocyte–antigen contact site, thereby allowing the formation and maintenance of a unique competent immune synapse.
Economic evaluations are far less frequently reported for medical devices than for drugs. In addition, little is known about the quality of existing economic evaluations, particularly for innovative ...devices, such as those used in vertebroplasty and kyphoplasty.
To assess the level of evidence provided by the available economic evaluations for vertebroplasty and kyphoplasty.
A systematic review of articles in English or French listed in the MEDLINE, PASCAL, COCHRANE and National Health Service Economic Evaluation databases, with limits on publication date (up to the date of the review, March 2014).
We included only economic evaluations of vertebroplasty or kyphoplasty. Editorial and methodological articles were excluded.
Data were extracted from articles by two authors working independently and using two analysis grids to measure the quality of economic evaluations.
Twenty-one studies met our inclusion criteria. All were published between 2008 and 2014. Eighteen (86%) were full economic evaluations. Cost-effectiveness analysis (CEA) was the most frequent type of economic evaluation, and was present in 11 (52%) studies. Only three CEAs complied fully with the British Medical Journal checklist. The quality of the data sources used in the 21 studies was high, but the CEAs conforming to methodological guidelines did not use high-quality data sources for all components of the analysis.
This systematic review shows that the level of evidence in economic evaluations of vertebroplasty and kyphoplasty is low, despite the recent publication of a large number of studies. This finding highlights the challenges to be faced to improve the quality of economic evaluations of medical devices.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The purpose of this study was to compare the cost-effectiveness of coils versus the Amplatzer Vascular Plug (AVP) for occlusion of the internal iliac artery (IAA). Between 2002 and January 2006, 13 ...patients (mean age 73 ± 13 years) were referred for stent-grafting of abdominal aortic aneurysm (
n
= 6); type I distal endoleak (
n
= 3), isolated iliac aneurysm (
n
= 3), or rupture of a common iliac aneurysm (
n
= 1). In all patients, extension of the stent-graft was needed because the distal neck was absent. Two different techniques were used to occlude the IIA: AVP in seven patients (group A) and coil embolization in six patients (group C). Immediate results and direct material costs were assessed retrospectively. Immediate success was achieved in all patients, and simultaneous stent-grafting was successfully performed in two of six patients in group C versus five of seven patients in group A. In all group A patients, a single AVP was sufficient to achieve occlusion of the IIA, accounting for a mean cost of 485 €, whereas in group C patients, an average of 7 ± 3 coils were used, accounting for a mean cost of 1,745 €. Mean average cost savings using the AVP was 1,239 €. When IIA occlusion is needed, the AVP allows a single-step procedure at significant cost savings.
Three-dimensional (3D) printing has changed surgical practice over the past few years, especially in maxillofacial surgery. However, little is known about its real clinical impact. The objectives of ...our study were to identify clinical outcomes that have been evaluated in the literature regarding 3D printing applications in jaw reconstruction, and to quantify the impact of this technology on operating times.
A systematic review was conducted by searching PubMed and EMBASE to collect comparative studies on 3D printing applications in jaw reconstruction. A meta-analysis of operating times was then performed. A Cochran's Q test was used to determine heterogeneity, and the overall effect size was calculated using a random effects model.
Fourteen studies were included in our review. Eighteen clinical end-points were identified, of which the most frequently reported were operating time (n = 5; 35.7%) and the final aesthetic result (n = 4; 28.6%). Operating times were significantly lower in the 3D printing groups, with an overall estimated effect of 21.2% (95% CI 10–33%; p < 0.001).
The use of 3D printing in jaw reconstruction was associated with a significant reduction in operating times. The end-points evaluated differed largely among the studies. More studies with higher levels of evidence are needed to confirm our results.
The study of lymphocyte polarization upon antigen encounter typically relies on the random pairing between the cells of interest and a stimulating particle (micro bead) that mimics only some of the ...properties of the antigen-presenting cells. Here, we show how to build and use a microfluidic chip that allows to multiplex and synchronize the encounter between a lymphocyte and an antigen-presenting object: a functionalized oil-in-water droplet. We also explain how to fabricate and functionalize lipid droplets, an antigen-presenting tool that is, at the same time, deformable, fluid, and spherical.
Introduction
The Medical Devices Regulation (MDR) 2017/745/EU will fully apply from May 2020. Interventional radiologists use medical devices on a daily basis and so must be aware of the impact that ...this new regulation will have on their daily practice.
Materials and Methods
In this paper, we describe the major transformation that the MDR brings to the medical devices sector, with a focus on clinical evaluations and clinical investigations.
Results
This regulation significantly tightens controls to ensure that devices are safe and effective. In addition, equivalence to already existing devices, which allowed an accelerated access to the market, will now be possible only in some cases. Furthermore, post-marketing clinical follow-up is extended under the MDR and is required for all devices. These new requirements will probably lead to a dramatic increase in the number of clinical investigations and also to a delay in the availability of certain devices on the market.
Conclusions
In the coming years, interventional radiologists are likely to be affected by these changes in their daily practice, in terms of medical device availability and/or in terms of increased involvement in clinical investigations.
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