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1.
Prenat Diagn ; 44(8): 988-995, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38797992

RESUMO

OBJECTIVE: We aim to provide a template structured report of fetal Magnetic Resonance Imaging in congenital diaphragmatic hernia (CDH) that was locally validated by the CDH study group in Mannheim. METHODS: A selection of 50 fetal MRIs of patients with an isolated diaphragmatic hernia and associated radiology reports from five different senior radiologists from a single center resulted in a primary structured report, which was put into practice by using dedicated software. A questionnaire survey of the interdisciplinary CDH study group Mannheim was used to adapt the report to the clinical requirements. RESULTS: There was a huge variability in how deep the free text reports go into detail. The side of the hernia was named in 94% of cases. In 58%, both the lung volume and the total lung volume were reported. A comparison with the expected lung volume was reported in 66% of cases. Additional findings, such as herniated organs, were reported in 96% of cases. Overall satisfaction with the newly established structured report was high within the CDH study group with a mean of 4.7. CONCLUSIONS: The use of the structured report of this study can optimize the interdisciplinary dialog, the standardization of report content, increase report completeness and improve quality.


Assuntos
Hérnias Diafragmáticas Congênitas , Imageamento por Ressonância Magnética , Humanos , Hérnias Diafragmáticas Congênitas/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Feminino , Gravidez , Diagnóstico Pré-Natal/métodos , Inquéritos e Questionários
2.
Radiologie (Heidelb) ; 64(5): 366-372, 2024 May.
Artigo em Alemão | MEDLINE | ID: mdl-38587632

RESUMO

STANDARD RADIOLOGICAL METHODS: Fetal: Ultrasound and magnetic resonance imaging (MRI); postnatal: conventional X­ray diagnostics, computed tomography (CT) and MRI. METHODICAL INNOVATIONS: MRI-based lung ventilation and perfusion measurement. PRACTICAL RECOMMENDATIONS: Lifelong follow-up care should be provided, in which radiology is part of the treatment team.


Assuntos
Hérnias Diafragmáticas Congênitas , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez , Assistência ao Convalescente , Hérnias Diafragmáticas Congênitas/diagnóstico por imagem , Hérnias Diafragmáticas Congênitas/cirurgia , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Ultrassonografia Pré-Natal/métodos
3.
Radiologie (Heidelb) ; 63(10): 729-735, 2023 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-37407747

RESUMO

CLINICAL/METHODICAL ISSUE: Differentiating between septic arthritis and transient synovitis can be challenging but is very important as a late diagnosis of septic arthritis can lead to sepsis and joint damage. For correct diagnosis and prediction of complications, the right combination of physical examination, laboratory and radiological studies is needed. STANDARD RADIOLOGICAL METHODS: Hip ultrasound is easy to learn and has a high sensitivity for joint effusion. Faster diagnosis and therapy are possible due to increasing use of ultrasound. Magnetic resonance imaging (MRI) is primarily used to rule out co-infections (osteomyelitis, pyomyositis) and differential diagnoses. X­ray is typically nonremarkable in septic arthritis. PRACTICAL RECOMMENDATIONS: Routine use of ultrasound in nontraumatic pediatric hip pain. Generous use of MRI in case of elevated inflammatory markers or inconclusive clinical findings. Using only few sequences may be appropriate to avoid sedation, primarily fluid sensitive sequences (fat-saturated T2, TIRM, STIR), in case of positive findings, accompanied by T1-weighted images.


Assuntos
Artrite Infecciosa , Sinovite , Criança , Humanos , Articulação do Quadril/diagnóstico por imagem , Articulação do Quadril/patologia , Sinovite/diagnóstico por imagem , Sinovite/patologia , Artrite Infecciosa/diagnóstico por imagem , Artrite Infecciosa/patologia , Quadril/patologia , Radiografia
4.
Rev Sci Instrum ; 94(5)2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-37184347

RESUMO

We report on progress implementing and testing cryogenically cooled platforms for Magnetized Liner Inertial Fusion (MagLIF) experiments. Two cryogenically cooled experimental platforms were developed: an integrated platform fielded on the Z pulsed power generator that combines magnetization, laser preheat, and pulsed-power-driven fuel compression and a laser-only platform in a separate chamber that enables measurements of the laser preheat energy using shadowgraphy measurements. The laser-only experiments suggest that ∼89% ± 10% of the incident energy is coupled to the fuel in cooled targets across the energy range tested, significantly higher than previous warm experiments that achieved at most 67% coupling and in line with simulation predictions. The laser preheat configuration was applied to a cryogenically cooled integrated experiment that used a novel cryostat configuration that cooled the MagLIF liner from both ends. The integrated experiment, z3576, coupled 2.32 ± 0.25 kJ preheat energy to the fuel, the highest to-date, demonstrated excellent temperature control and nominal current delivery, and produced one of the highest pressure stagnations as determined by a Bayesian analysis of the data.

5.
Radiologie (Heidelb) ; 63(4): 275-283, 2023 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-36811691

RESUMO

CLINICAL/METHODOLOGICAL ISSUE: Due to active participation of children and adolescents in school sports as well as in club sports, sporting injuries in childhood are common. Because skeletal maturity is not yet complete, injury patterns in children differ from sporting injuries in adults. Knowledge of the pathophysiologic characteristics, as well as knowledge of typical injury sequelae, is of great relevance to radiologists. This review article therefore deals with common acute and chronic sporting injuries in children. STANDARD RADIOLOGICAL METHODS: Basic diagnostic imaging comprises conventional X­ray imaging in two planes. In addition, sonography, magnetic resonance imaging (MRI) and computed tomography (CT) are used. PRACTICAL RECOMMENDATIONS: Close consultation with clinical colleagues and knowledge of childhood-specific injuries help identify sports-associated trauma sequelae.


Assuntos
Traumatismos em Atletas , Esportes , Adulto , Humanos , Criança , Adolescente , Traumatismos em Atletas/diagnóstico por imagem , Traumatismos em Atletas/etiologia , Imageamento por Ressonância Magnética
6.
Phys Rev Lett ; 128(25): 255001, 2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-35802445

RESUMO

The magneto-Rayleigh-Taylor instability (MRTI) plays an essential role in astrophysical systems and in magneto-inertial fusion, where it is known to be an important degradation mechanism of confinement and target performance. In this Letter, we show for the first time experimental evidence of mode mixing and the onset of an inverse-cascade process resulting from the nonlinear coupling of two discrete preseeded axial modes (400- and 550-µm wavelengths) on an Al liner that is magnetically imploded using the 20-MA, 100-ns rise-time Z Machine at Sandia National Laboratories. Four radiographs captured the temporal evolution of the MRTI. We introduce a novel unfold technique to analyze the experimental radiographs and compare the results to simulations and to a weakly nonlinear model. We find good quantitative agreement with simulations using the radiation magnetohydrodynamics code hydra. Spectral analysis of the MRTI time evolution obtained from the simulations shows evidence of harmonic generation, mode coupling, and the onset of an inverse-cascade process. The experiments provide a benchmark for future work on the MRTI and motivate the development of new analytical theories to better understand this instability.

7.
Anaesthesist ; 70(3): 204-212, 2021 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-33001236

RESUMO

BACKGROUND: Levosimendan is a cardiac inotrope that augments myocardial contractility without increasing myocyte oxygen consumption. Additionally, levosimendan has been shown to exhibit anti-inflammatory, antioxidative, and other cardioprotective properties and is approved for treatment of heart failure. Recent studies indicated that these beneficial effects can be achieved with doses lower than the standard dose of 12.5 mg. Patients with preoperatively diagnosed left ventricular ejection fraction (LVEF) ≤40% received 1.25 mg levosimendan after induction of anesthesia. After surgery, administration of low-dose levosimendan was repeated until cardiovascular stability was achieved. OBJECTIVE: This study aimed to evaluate if pharmacological preconditioning with 1.25 mg levosimendan in patients with LVEF ≤40% altered the postoperative need for inotropic agents, the incidence of newly occurring atrial fibrillation, renal replacement therapy, mechanical circulatory support and 30-day mortality. The cumulative dosage of levosimendan was recorded to assess the required dosage in the context of individualized treatment. MATERIAL AND METHODS: This retrospective study included patients with preoperatively diagnosed LVEF ≤40% who underwent cardiac surgery at this institution between January 2015 and December 2018 and who received 1.25 mg levosimendan after induction of anesthesia to prevent postoperative low cardiac output syndrome. Based on echocardiography results, invasive hemodynamic monitoring, and central venous or mixed venous oxygen saturation and lactate clearance, repetitive doses of levosimendan in 1.25 mg increments could be postoperatively administered until cardiovascular stability was achieved. The results were compared to the current literature. RESULTS: We identified 183 patients with LVEF <40% who received pharmacological preconditioning with 1.25 mg levosimendan. Maximum doses of epinephrine, incidence of atrial fibrillation, need for renal replacement therapy and 30-day mortality were found to be below the published rates of comparable patient collectives. In 73.2% of patients, a cumulative dosage of 5 mg levosimendan or less was considered sufficient. CONCLUSION: The presented concept of pharmacological preconditioning with 1.25 mg levosimendan followed by individualized additional dosing in cardiac surgery patients with preoperative LVEF ≤40% suggests that this concept is safe, with possible advantages regarding the need of inotropic agents, renal replacement therapy, and 30-day mortality, compared to the current literature. Individualized treatment with levosimendan to support hemodynamics and a timely reduction of inotropic agents needs further confirmation in randomized trials.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Piridazinas , Baixo Débito Cardíaco/tratamento farmacológico , Baixo Débito Cardíaco/prevenção & controle , Cardiotônicos/uso terapêutico , Humanos , Hidrazonas/uso terapêutico , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/prevenção & controle , Piridazinas/uso terapêutico , Estudos Retrospectivos , Simendana/farmacologia , Volume Sistólico , Função Ventricular Esquerda
8.
Phys Rev Lett ; 125(15): 155002, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33095639

RESUMO

We present experimental results from the first systematic study of performance scaling with drive parameters for a magnetoinertial fusion concept. In magnetized liner inertial fusion experiments, the burn-averaged ion temperature doubles to 3.1 keV and the primary deuterium-deuterium neutron yield increases by more than an order of magnitude to 1.1×10^{13} (2 kJ deuterium-tritium equivalent) through a simultaneous increase in the applied magnetic field (from 10.4 to 15.9 T), laser preheat energy (from 0.46 to 1.2 kJ), and current coupling (from 16 to 20 MA). Individual parametric scans of the initial magnetic field and laser preheat energy show the expected trends, demonstrating the importance of magnetic insulation and the impact of the Nernst effect for this concept. A drive-current scan shows that present experiments operate close to the point where implosion stability is a limiting factor in performance, demonstrating the need to raise fuel pressure as drive current is increased. Simulations that capture these experimental trends indicate that another order of magnitude increase in yield on the Z facility is possible with additional increases of input parameters.

9.
Phys Rev E ; 102(2-1): 023209, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32942382

RESUMO

We present two-dimensional temperature measurements of magnetized and unmagnetized plasma experiments performed at Z relevant to the preheat stage in magnetized liner inertial fusion. The deuterium gas fill was doped with a trace amount of argon for spectroscopy purposes, and time-integrated spatially resolved spectra and narrow-band images were collected in both experiments. The spectrum and image data were included in two separate multiobjective analysis methods to extract the electron temperature spatial distribution T_{e}(r,z). The results indicate that the magnetic field increases T_{e}, the axial extent of the laser heating, and the magnitude of the radial temperature gradients. Comparisons with simulations reveal that the simulations overpredict the extent of the laser heating and underpredict the temperature. Temperature gradient scale lengths extracted from the measurements also permit an assessment of the importance of nonlocal heat transport.

11.
Eur J Radiol ; 105: 148-152, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30017271

RESUMO

PURPOSE: To evaluate liver-herniation as individual parameter on outcome in children with congenital diaphragmatic hernia. MATERIALS AND METHODS: In a retrospective matched-pair analysis based on observed to expected fetal lung volume (o/e FLV), birth weight, gestational age at time-point of examination, status of tracheal occlusion therapy and side of the defect the individual impact of liver-herniation on survival, need for extracorporeal membrane oxygenation (ECMO) therapy and chronic lung disease (CLD) was investigated. In total 61 pairs (122 patients) were included. Fisher's exact test was used to evaluate influence of liver-herniation and a p-value of <0.05 was defined as statistically significant. The study was approved by the local review board. RESULTS: Children with liver-herniation have lower survival rates (78.7% vs. 95.1%; p = 0.0073), need ECMO-therapy more often (41.0% vs. 16.4%; p = 0.0027) and are more likely to develop CLD (71.7% vs. 37.9%; p = 0.0004) than their corresponding matched-pair without liver-herniation. CONCLUSION: Liver-herniation itself and not further lung-volume restriction due to liver-herniation is responsible for poor outcome in CDH.


Assuntos
Oxigenação por Membrana Extracorpórea/estatística & dados numéricos , Doenças Fetais/diagnóstico por imagem , Hérnias Diafragmáticas Congênitas/diagnóstico por imagem , Hepatopatias/diagnóstico por imagem , Fígado/diagnóstico por imagem , Imageamento por Ressonância Magnética , Feminino , Doenças Fetais/patologia , Idade Gestacional , Hérnias Diafragmáticas Congênitas/embriologia , Hérnias Diafragmáticas Congênitas/patologia , Humanos , Recém-Nascido , Fígado/embriologia , Hepatopatias/embriologia , Hepatopatias/patologia , Medidas de Volume Pulmonar , Masculino , Análise por Pareamento , Estudos Retrospectivos , Taxa de Sobrevida
12.
Rev Sci Instrum ; 88(10): 103503, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29092482

RESUMO

Many experiments on Sandia National Laboratories' Z Pulsed Power Facility-a 30 MA, 100 ns rise-time, pulsed-power driver-use a monochromatic quartz crystal backlighter system at 1.865 keV (Si Heα) or 6.151 keV (Mn Heα) x-ray energy to radiograph an imploding liner (cylindrical tube) or wire array z-pinch. The x-ray source is generated by the Z-Beamlet laser, which provides two 527-nm, 1 kJ, 1-ns laser pulses. Radiographs of imploding, thick-walled beryllium liners at convergence ratios CR above 15 [CR=ri(0)/ri(t)] using the 6.151-keV backlighter system were too opaque to identify the inner radius ri of the liner with high confidence, demonstrating the need for a higher-energy x-ray radiography system. Here, we present a 7.242 keV backlighter system using a Ge(335) spherical crystal with the Co Heα resonance line. This system operates at a similar Bragg angle as the existing 1.865 keV and 6.151 keV backlighters, enhancing our capabilities for two-color, two-frame radiography without modifying the system integration at Z. The first data taken at Z include 6.2-keV and 7.2-keV two-color radiographs as well as radiographs of low-convergence (CR about 4-5), high-areal-density liner implosions.

13.
Sci Rep ; 7(1): 13782, 2017 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-29061972

RESUMO

Heralded as one of the key elements for next generation spintronics devices, topological insulators (TIs) are now step by step envisioned as nanodevices like charge-to-spin current conversion or as Dirac fermions based nanometer Schottky diode for example. However, reduced to few nanometers, TIs layers exhibit a profound modification of the electronic structure and the consequence of this quantum size effect on the fundamental carriers and phonons ultrafast dynamics has been poorly investigated so far. Here, thanks to a complete study of a set of high quality molecular beam epitaxy grown nanolayers, we report the existence of a critical thickness of around ~6 nm, below which a spectacular reduction of the carrier relaxation time by a factor of ten is found in comparison to bulk Bi2 Te3 In addition, we also evidence an A1g optical phonon mode softening together with the appearance of a thickness dependence of the photoinduced coherent acoustic phonons signals. This drastic evolution of the carriers and phonons dynamics might be due an important electron-phonon coupling evolution due to the quantum confinement. These properties have to be taken into account for future TIs-based spintronic devices.

14.
J Cardiothorac Surg ; 11(1): 120, 2016 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-27488025

RESUMO

BACKGROUND: Infection is a main cause of morbidity and mortality after heart surgery, with multi-resistant pathogens increasingly representing a challenge. Daptomycin provides bactericidal activity against gram-positive organisms that are resistant to standard treatment including vancomycin. METHODS: A cohort of cardiac surgical patients, treated with daptomycin for major infection at two tertiary care centers, were retrospectively studied with a particular focus on the type of infection, causative pathogens and co-infections, daptomycin dosage, adverse events and outcome in order to provide evidence for the efficiency and safety of daptomycin in a distinct high-risk patient population. RESULTS: Sixty-five patients (87.7 % males, 60.4 ± 13.5 years) who had undergone aortic surgery (20.0 %), ventricular assist device (VAD) implantation (21.5 %), combined procedures (21.5 %), coronary artery bypass grafting (12.3 %), isolated valve surgery (15.4 %) and heart transplantation (7.7 %) were diagnosed with catheter-related infection (26.1 %), valve endocarditis (18.8 %), sternal wound (13.0 %), VAD-associated (11.6 %), cardiac implantable electrophysiological device (CIED)-associated (4.1 %), respiratory tract (4.3 %), bloodstream (4.3 %) and other infection (4.3 %). In 13.0 %, no focus of infection was identified though symptoms of severe infection were present. The most frequent pathogens were Staphylococcus epidermidis (30.4 %), Staphylococcus aureus (23.1 %) and Enterococcus species (10.1 %). Daptomycin doses ranging from 3 mg/kg every 48 h to 10 mg/kg every 24 h were administered for 15.4 ± 11.8 days. 87.0 % of the cases were classified as success, 7.2 % as treatment failure and 5.8 as non-evaluable. Adverse events were limited to one case of mild and one case of moderate neutropenia with recovery upon termination of treatment. CONCLUSION: Daptomycin proved safe and effective in major infection in high-risk cardiac surgical patients.


Assuntos
Antibacterianos/uso terapêutico , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Daptomicina/uso terapêutico , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Infecções por Bactérias Gram-Positivas/microbiologia , Idoso , Feminino , Infecções por Bactérias Gram-Positivas/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
15.
J Pediatr Adolesc Gynecol ; 29(6): 659-667, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27386754

RESUMO

STUDY OBJECTIVE: Adolescents are at high risk for unintended pregnancies. Although intrauterine devices (IUDs), long-acting reversible contraceptives (LARCs), are known to be highly effective in preventing pregnancy, little is known about IUD adherence in adolescents. In this systematic review (SR) we examined IUD continuation rates compared with other forms of contraception in young women aged 25 years and younger. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: A systematic search of Ovid Medline, Cochrane Library, and Embase was conducted for the years 1946-2015. Included studies examined IUD use in women 25 years of age and younger, compared IUD use with another form of contraception, and measured continuation rates at 12 months. The quality of each study was appraised using the Downs and Black criteria, and 12-month continuation rates among studies were pooled and analyzed according to contraceptive type. RESULTS: Of 3597 articles retrieved, 9 studies met criteria for SR. Synthesized across studies, 12-month continuation was significantly higher for IUD users (86.5%, 12,761/14,747) compared with oral contraceptives (39.6%, 1931/4873), Depo-Provera (Pfizer Inc, New York, NY) hormonal injection (39.8%, 510/1282), vaginal ring (48.9%, 196/401), and transdermal patch (39.8%, 37/93; all P values < .001). There was no statistically significant difference in 12-month continuation between the IUD and another LARC method, the subdermal etonogestrel implant (85.3%, 4671/5474). CONCLUSION: Findings of this SR suggest that continuation rates for IUDs are generally higher compared with other contraceptive methods for women aged 25 years and younger. In a population with high rates of unintended pregnancies, generally low adherence, and imperfect use with other non-LARCs, IUD use should be encouraged.


Assuntos
Comportamento Contraceptivo , Anticoncepção/métodos , Dispositivos Intrauterinos/estatística & dados numéricos , Cooperação do Paciente/estatística & dados numéricos , Adolescente , Adulto , Anticoncepcionais Femininos/uso terapêutico , Dispositivos Anticoncepcionais Femininos/estatística & dados numéricos , Anticoncepcionais Orais/uso terapêutico , Desogestrel/uso terapêutico , Feminino , Humanos , Acetato de Medroxiprogesterona/uso terapêutico , Gravidez , Gravidez não Planejada , Fatores de Tempo , Adulto Jovem
16.
Eur Radiol ; 26(12): 4231-4238, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27048538

RESUMO

OBJECTIVE: With a region of interest (ROI)-based approach 2-year-old children after congenital diaphragmatic hernia (CDH) show reduced MR lung perfusion values on the ipsilateral side compared to the contralateral. This study evaluates whether results can be reproduced by segmentation of whole-lung and whether there are differences between the ROI-based and whole-lung measurements. METHODS: Using dynamic contrast-enhanced (DCE) MRI, pulmonary blood flow (PBF), pulmonary blood volume (PBV) and mean transit time (MTT) were quantified in 30 children after CDH repair. Quantification results of an ROI-based (six cylindrical ROIs generated of five adjacent slices per lung-side) and a whole-lung segmentation approach were compared. RESULTS: In both approaches PBF and PBV were significantly reduced on the ipsilateral side (p always <0.0001). In ipsilateral lungs, PBF of the ROI-based and the whole-lung segmentation-based approach was equal (p=0.50). In contralateral lungs, the ROI-based approach significantly overestimated PBF in comparison to the whole-lung segmentation approach by approximately 9.5 % (p=0.0013). CONCLUSIONS: MR lung perfusion in 2-year-old children after CDH is significantly reduced ipsilaterally. In the contralateral lung, the ROI-based approach significantly overestimates perfusion, which can be explained by exclusion of the most ventral parts of the lung. Therefore whole-lung segmentation should be preferred. KEY POINTS: • Ipsilaterally, absolute lung perfusion after CDH is reduced in whole-lung analysis. • Ipsilaterally, the ROI- and whole-lung-based approaches generate identical results. • Contralaterally, the ROI-based approach significantly overestimates perfusion results. • Whole lung should be analysed in MR lung perfusion imaging. • MR lung perfusion measurement is a radiation-free parameter of lung function.


Assuntos
Hérnias Diafragmáticas Congênitas/cirurgia , Pulmão/irrigação sanguínea , Pulmão/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Cuidados Pós-Operatórios/métodos , Fluxo Sanguíneo Regional/fisiologia , Volume Sanguíneo , Pré-Escolar , Meios de Contraste , Feminino , Humanos , Aumento da Imagem , Masculino , Reprodutibilidade dos Testes
17.
Osteoarthritis Cartilage ; 24(6): 1029-35, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26790721

RESUMO

OBJECTIVE: To determine if type III collagen is concentrated in the chymotrypsin-extractable collagen pool from osteoarthritic articular cartilage to assess its potential as a biomarker of Osteoarthritis (OA) pathogenic mechanisms. METHODS: Full thickness articular cartilage from grossly normal surfaces was analyzed from femoral heads, obtained at hip replacement surgery, from OA (n = 10) and fracture (n = 10) patients. Collagen, extracted by α-chymotrypsin, was characterized by SDS-PAGE/Western blot analysis, ELISA and immunohistochemistry using monoclonal antibodies specific to collagens types II and III. RESULTS: α-Chymotrypsin extracted more collagen from OA than control cartilage. The extractable pool included collagen types II and III from both OA and control hips. Importantly, OA cartilage contained 6-fold more collagen type III than control cartilage, based on ELISA. The estimated total tissue ratio of collagen III/II was in the 1-10% range for individual OA cartilage samples, based on pepsin-solubilized collagen using SDS-PAGE densitometry. Collagen type III N-propeptide trimers were the main molecular fragments seen on Western blot analysis of OA and control extracts. The chymotrypsin-extracted type II collagen gave primarily full-length α1(II) chains and chain fragments of α1(II) on Western blot analysis from both OA and control tissues. Immunohistochemistry showed that type III collagen was more concentrated in the upper half of OA cartilage and in the territorial matrix around individual chondrocytes and chondrocyte clusters. CONCLUSIONS: The findings confirm that collagen type III deposition occurs in adult articular cartilage but significantly more pronounced in osteoarthritic joints, presenting a potential marker of matrix repair or pathobiology.


Assuntos
Cartilagem Articular , Condrócitos , Quimotripsina , Colágeno Tipo II , Colágeno Tipo III , Humanos , Osteoartrite
18.
Radiologe ; 56(2): 113-23, 2016 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-26796337

RESUMO

CLINICAL/METHODICAL ISSUE: Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. STANDARD RADIOLOGICAL METHODS: Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. PERFORMANCE: Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. ACHIEVEMENTS: The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. PRACTICAL RECOMMENDATIONS: The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Vasos Sanguíneos/fisiologia , Determinação do Volume Sanguíneo/métodos , Volume Sanguíneo/fisiologia , Gadolínio/farmacocinética , Angiografia por Ressonância Magnética/métodos , Animais , Simulação por Computador , Meios de Contraste/farmacocinética , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Modelos Cardiovasculares
19.
Artigo em Inglês | MEDLINE | ID: mdl-25571236

RESUMO

In this contribution we introduce the Parallel Factor 2 (PARAFAC2) analysis as a novel method for the simultaneous detection and classification of neural action potentials. In order to measure these action potentials (spike signals), stem cell derived neuronal cells are cultivated on the surface of a Micro Electrode Array (MEA). Here, the neuronal cells produce ion currents, which can be measured as extracellular electric potentials. Whenever a cell or a group of cells produces ion currents, either spontaneously or evoked by a stimulus, a spike signal can be measured by the electrodes of the MEA. Stimulated cells produce spikes and groups of spikes (bursts) which propagate in space over the MEA. In the recorded data, different source types (e.g., cells which respond directly to external stimuli and cells which are triggered by other neural cells) are characterized by different spike shapes. The proposed PARAFAC2 method is able to separate these spike shapes (sources) in time, frequency and space (channels) enabling an improved performance in noisy scenarios. Furthermore, PARAFAC2 allows for a causality analysis on the measured spike signals (i.e. the identification of different signal paths). Thereby, the PARAFAC2 decomposition is able to exploit the multi-dimensional structure of the MEA data.


Assuntos
Potenciais de Ação , Processamento de Sinais Assistido por Computador , Células Cultivadas , Eletrodos , Humanos , Neurônios/fisiologia
20.
Langmuir ; 28(25): 9395-404, 2012 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-22662960

RESUMO

An original diffraction model for the analysis of grazing-incidence small-angle X-ray scattering (GISAXS) from the nanoparticle Langmuir films was developed. This model relies on the concept of the 2D hexagonal paracrystal and employs the distorted-wave Born approximation that is relevant for GISAXS measurements at the air/water interface when the angle of incidence is close to the critical value. The model comprises the cases of the close-packed nanoparticle monolayer and bilayer with the AB-type layer stacking. In this way, both the lateral (along the interface) and vertical (normal to the interface) correlations of the nanoparticle positions can be analyzed. The model was applied to an in situ GISAXS study of the formation of a silver nanoparticle Langmuir film during compression at the air/water interface in the Langmuir-Blodgett trough. Spherical nanoparticles of 5.8 ± 0.6 nm diameter were employed. Different compression stages starting from the submonolayer up to the monolayer collapse via bilayer formation were analyzed in terms of the mean lateral interparticle distance, degree of paracrystal disorder, interlayer distance, vertical disorder, and layer-stacking type in the bilayer as well as the ratio between the monolayer and bilayer coverage in the final film. The model developed is applicable to any nanoparticle Langmuir film formed at the air/liquid interface to extract structural parameters on the nanoscale. The particular results obtained have direct implications on the preparation of silver plasmonic templates with "hot spots" for surface-enhanced Raman scattering.

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