MARIA (magnetism reflectometer with high incident angle) is a world class vertical sample reflectometer dedicated to the investigation of thin films in the fields of magnetism, soft matter and ...biology. The elliptical vertically focusing guide allows one to measure small samples with a typical size of 1 × 1 cm very efficiently. The double‐bounce polarizer and the in situ pumped 3He SEOP (spin‐exchange optical pumping) neutron spin filter cell for analysing the polarization of the reflected neutron beam can be moved into the beam in seconds. The polarized flux of MARIA amounts to 5 × 107 n (s cm2)−1 at the sample position with a horizontally collimated beam of 3 mrad, a wavelength of λ = 4.5 Å and a wavelength resolution of Δλ/λ = 10%. In the non‐polarized mode a flux of 1.2 × 108 n (s cm2)−1 is achieved in this configuration. MARIA is also capable of grazing‐incidence small‐angle neutron scattering measurements, using a pinhole collimation with two four‐segment slits and an absorber that prevents the focusing of the elliptical guide in the vertical direction.
MARIA is a world class vertical sample reflectometer dedicated to the investigation of thin films in the fields of magnetism, soft matter and biology. With the elliptical vertically focusing guide and a wavelength resolution of Δλ/λ = 10%, the non‐polarized flux at the sample position amounts to 1.2 × 108 n (s cm2)−1. Besides the polarized and non‐polarized reflectivity mode for specular and off‐specular reflectivity measurements, MARIA can also be used to carry out grazing‐incidence small‐angle neutron scattering investigations.
MARIA is a world class vertical sample reflectometer dedicated to the investigation of thin films in the fields of magnetism, soft matter and biology. With the elliptical vertically focusing guide ...and a wavelength resolution of Δλ/λ = 10%, the non-polarized flux at the sample position amounts to 1.2 × 10
8
n (s cm
2
)
−1
. Besides the polarized and non-polarized reflectivity mode for specular and off-specular reflectivity measurements, MARIA can also be used to carry out grazing-incidence small-angle neutron scattering investigations.
MARIA (magnetism reflectometer with high incident angle) is a world class vertical sample reflectometer dedicated to the investigation of thin films in the fields of magnetism, soft matter and biology. The elliptical vertically focusing guide allows one to measure small samples with a typical size of 1 × 1 cm very efficiently. The double-bounce polarizer and the
in situ
pumped
3
He SEOP (spin-exchange optical pumping) neutron spin filter cell for analysing the polarization of the reflected neutron beam can be moved into the beam in seconds. The polarized flux of MARIA amounts to 5 × 10
7
n (s cm
2
)
−1
at the sample position with a horizontally collimated beam of 3 mrad, a wavelength of λ = 4.5 Å and a wavelength resolution of Δλ/λ = 10%. In the non-polarized mode a flux of 1.2 × 10
8
n (s cm
2
)
−1
is achieved in this configuration. MARIA is also capable of grazing-incidence small-angle neutron scattering measurements, using a pinhole collimation with two four-segment slits and an absorber that prevents the focusing of the elliptical guide in the vertical direction.
Aims Our objective was to study the effect of the genetic background on the wound healing process after myocardial infarction (MI) in mice. Methods and results MI was induced in five different mouse ...strains (BalbC, C57Bl6, FVB, 129S6, and Swiss). At 3, 14, and 28 days after MI, cardiac dimensions were monitored by echocardiography and histology, whereas cardiac function was determined by direct intraventricular pressure measurements (dP/dt). Furthermore, matrix metalloproteinases were measured by zymography, and mRNA expression by quantitative PCR. Infarct rupture, which typically occurred at 3–6 days post-MI, was most frequent in 129S6 mice (62%), followed by C57Bl6 (36%), FVB (29%), Swiss (23%), and BalbC (5%). The high incidence of infarct rupture in 129S6 mice was associated with high systolic blood pressure and increased influx of inflammatory cells. Cardiac dilatation was most marked in Swiss mice and least prominent in 129S6 mice. The degree of dilatation was associated with a reduced ejection fraction and decreased dP/dt values at 14 and 28 days post-MI. At day 14 and 28 post-MI, secondary thinning of the infarct area was marked in BalbC, FVB, and Swiss, but absent in C57Bl6 and 129S6 mice. In the latter two groups, this was paralleled by the highest number of myofibroblasts at day 14 post-MI. Conclusion The outcome of infarct healing in mice strongly depends on genetic background. On the basis of our results, we suggest that for studies on infarct rupture, the 129S6 mouse is the background of choice, whereas BalbC and Swiss mice are the preferred models to study infarct thinning post-MI.
ABSTRACT—Increased activity of matrix metalloproteinases (MMPs) has been implicated in numerous disease processes, including tumor growth and metastasis, arthritis, and periodontal disease. It is now ...becoming increasingly clear that extracellular matrix degradation by MMPs is also involved in the pathogenesis of cardiovascular disease, including atherosclerosis, restenosis, dilated cardiomyopathy, and myocardial infarction. Administration of synthetic MMP inhibitors in experimental animal models of these cardiovascular diseases significantly inhibits the progression of, respectively, atherosclerotic lesion formation, neointima formation, left ventricular remodeling, pump dysfunction, and infarct healing. This review focuses on the role of MMPs in cardiovascular disease, in particular myocardial infarction and the subsequent progression to heart failure. MMPs, which are present in the myocardium and capable of degrading all the matrix components of the heart, are the driving force behind myocardial matrix remodeling. The recent finding that acute pharmacological inhibition of MMPs or deficiency in MMP-9 attenuates left ventricular dilatation in the infarcted mouse heart led to the proposal that MMP inhibitors could be used as a potential therapy for patients at risk for the development of heart failure after myocardial infarction. Although these promising results encourage the design of clinical trials with MMP inhibitors, there are still several unresolved issues. This review describes the biology of MMPs and discusses new insights into the role of MMPs in several cardiovascular diseases. Attention will be paid to the central role of the plasminogen system as an important activator of MMPs in the remodeling process after myocardial infarction. Finally, we speculate on the use of MMP inhibitors as potential therapy for heart failure.
The aim of this study was to develop a high-fidelity minimally invasive mitral valve surgery (MIMVS) simulator.
The process of industrial serial design was applied based on pre-set requirements, ...acquired by interviewing experienced mitral surgeons. A thoracic torso with endoscopic and robotic access and disposable silicone mitral valve apparatus with a feedback system was developed. The feedback system was based on 4 cameras around the silicone valve and an edge detection algorithm to calculate suture depth and width. Validity of simulator measurements was assessed by comparing simulator-generated values with measurements done manually on 3-dimensional reconstructed micro-computed tomography scan of the same sutures. Independent surgeons tested the simulator between 2014 and 2018, whereupon an evaluation was done through a questionnaire.
The feedback system was able to provide width and depth measurements, which were subsequently scored by comparison to pre-set target values. Depth did not significantly differ between simulator and micro-computed tomography scan measurements (P = .139). Width differed significantly (P = .001), whereupon a significant regression equation was found (P < .0001) to calibrate the simulator. After calibration, no significant difference was found (P = .865). In total, 99 surgeons tested the simulator and more than agreed with the statements that the simulator is a good method for training MIMVS, and that the mitral valve and suture placement looked and felt realistic.
We successfully developed a high-fidelity MIMVS simulator for endoscopic and robotic approaches. The simulator provides a platform to train skills in an objective and reproducible manner. Future studies are needed to provide evidence for its application in training surgeons.
Staphylococcus aureus is a major human and animal pathogen and a common cause of mastitis in cattle. S. aureus secretes several leukocidins that target bovine neutrophils, crucial effector cells in ...the defence against bacterial pathogens. In this study, we investigated the role of staphylococcal leukocidins in the pathogenesis of bovine S. aureus disease. We show that LukAB, in contrast to the γ-hemolysins, LukED, and LukMF', was unable to kill bovine neutrophils, and identified CXCR2 as a bovine receptor for HlgAB and LukED. Furthermore, we assessed functional leukocidin secretion by bovine mastitis isolates and observed that, although leukocidin production was strain dependent, LukMF' was most abundantly secreted and the major toxin killing bovine neutrophils. To determine the role of LukMF' in bovine mastitis, cattle were challenged with high (S1444) or intermediate (S1449, S1463) LukMF'-producing isolates. Only animals infected with S1444 developed severe clinical symptoms. Importantly, LukM was produced in vivo during the course of infection and levels in milk were associated with the severity of mastitis. Altogether, these findings underline the importance of LukMF' as a virulence factor and support the development of therapeutic approaches targeting LukMF' to control S. aureus mastitis in cattle.
Reoperative mitral valve surgery (MVS) through a median sternotomy (ST-MVS) can be particularly challenging due to dense adhesions and is known to carry a substantial risk of injuries to vascular ...structures. These injuries occur in 7-9% of cases and are associated with increased mortality rates. A valid alternative that could avoid the risks associated with redo ST-MVS is the right anterolateral minithoracotomy (MT-MVS) approach. The aim of this study was to quantify the effects of MT-MVS compared with those of ST-MVS on morbidity and mortality among patients who underwent prior cardiac surgery through a sternotomy. The MEDLINE and EMBASE databases were searched through 1 November 2017. Data regarding mortality, stroke, reoperation for bleeding and length of hospital stay were extracted and submitted to a meta-analysis using random effects modelling and the I2-test for heterogeneity. Six retrospective observational studies were included, enrolling a total of 777 patients. In a pooled analysis, MT-MVS demonstrated reduced mortality rates compared to a standard sternotomy odds ratio (OR) 0.41, 95% confidence interval (CI) 0.18-0.96; P = 0.04. MT-MVS was, moreover, associated with reduced length of hospital stay difference between the means was -3.81, 95% CI -5.53 to -2.08; P < 0.0001) and reoperation for bleeding (OR 0.32, 95% CI 0.10-0.99; P = 0.0488). The incidence of stroke was similar (OR 1.51, 95% CI 0.65-3.54; P = 0.34), all in the absence of heterogeneity. In conclusion, reoperative minimally invasive MVS through a minithoracotomy is a safe alternative to standard sternotomy, with reduced mortality rates, length of hospital stay and reoperations for bleeding and a comparable risk of stroke. However, because the existing literature provided limited, low-quality evidence, more methodologically rigorous randomized controlled trials are needed.
Abstract
OBJECTIVES
The aim of this study was to develop a process for modelling and 3-dimensional (3D) printing of different mitral valve diseases for procedural planning and simulation, based on 3D ...transoesophageal echocardiography (TOE).
METHODS
3D TOE was used to reconstruct a fully dynamic 3D view of the diseased valve. Reconstructions were cropped at the level of the valve and captured in mid-systole to assess the coaptation defect. Reconstructions were then exported as a surface mesh. To ensure a watertight and noise-reduced model, the mesh was processed using computer-modelling programmes, whereupon the valve was printed in 3D. For simulation purposes, deformable models were created based on negative mould fabrication and cast in tissue-mimicking silicone. Model validation was performed by intraoperative assessment of the valvular disease and repair strategy.
RESULTS
The mitral valves of 10 prospective patients with different diseases were modelled. In 6 patients, a 3D printed rigid plastic mitral valve was created for procedural planning, and in 4 patients, a silicone-cast replica was created for procedural simulation. All models were created to scale, implying conservation of in vivo dimensions. Models were validated by in vivo comparison. Total workaround time ranged from 3 to 4 h and 2 to 3 days for rigid plastic and silicone models, respectively. Costs were €15 to €40 and €300, respectively.
CONCLUSIONS
We demonstrated the feasibility of creating rigid plastic and tissue-mimicking silicone mitral valve replications. These models could be used in the future to enhance surgical anatomical interpretation, to facilitate planning and simulation of complex surgeries and for training purposes.
Summary
Primary spontaneous pneumothorax affects up to 28 patients per 100 000 population yearly and is commonly resolved by chest tube drainage. However, drainage is also known to be associated with ...ipsilateral recurrence rates ranging from 25% to 43%. Preventive video-assisted thoracoscopic surgery (VATS) may be an effective alternative to diminish these recurrence rates and its associated morbidity. The aim of this study was to compare the efficacy of chest tube drainage and VATS as first line treatments of an initial episode of primary spontaneous pneumothorax. The MEDLINE, EMBASE, CENTRAL and Clinicaltrials.gov databases were searched through 16 September 2018. Data regarding the ipsilateral recurrence rate and the length of hospitalization were extracted and submitted to meta-analysis using the random-effects model and the I2 test for heterogeneity. Two randomized controlled trials and 2 observational studies were included, enrolling a total of 479 patients. Pairwise analysis demonstrated significantly reduced ipsilateral recurrence rates odds ratio 0.15, 95% confidence interval (CI) 0.07–0.33; P < 0.00001 and length of hospitalization (standardized mean difference −2.19, 95% CI −4.34 to −0.04; P = 0.046) in favour of VATS. However, a significant level of heterogeneity was detected for the length of hospitalization (I2 = 97%; P < 0.00001). Subgroup analysis that stratified study design found no statistical differences regarding recurrence rate. In conclusion, VATS can be an effective and attractive alternative to standard chest tube drainage, with reduced ipsilateral recurrence rates and length of hospitalization. However, given the low quality of the majority of included studies, more well-designed randomized controlled trials are necessary to strengthen the current evidence.
To define the learning process of minimally invasive repair of pectus excavatum by the Nuss procedure through assessment of consecutive procedural metrics.
A single-center retrospective observational ...cohort study was conducted of all consecutive Nuss procedures performed by individual surgeons without previous experience between June 2006 and December 2018. Surgeons were proctored during their initial 10 procedures. The learning process after the proctoring period was evaluated using nonrisk-adjusted cumulative sum (ie, observed minus expected) failure charts of complications. An acceptable and unacceptable complication rate of 10% and 20% were used. Logarithmic trend lines were used to assess over-time performance regarding operation time.
Two-hundred twenty-two consecutive Nuss procedures by 3 general thoracic surgeons were evaluated. Cumulative sum charts showed an average performance from the first procedure after being proctored onward for all surgeons, whereas surgeon B demonstrated a statistically significant complication rate equal to or less than 10% after 59 cases. Post-hoc sensitivity analyses using a stricter acceptable and unacceptable complication rate of 6% and 12% also showed an average performance for all surgeons. Although, the median time between consecutive procedures ranged from 7 to 35 days, no frequency–outcome relationship was observed. In addition, surgeons required the same average operation time throughout their entire experience.
After a 10-procedure proctoring period, repair of pectus excavatum by the Nuss procedure is a safe procedure to adopt and perform without a typical (complication based) learning curve while performing at least 1 procedure per 35 days.
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