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1.
Nature ; 622(7984): 818-825, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37821700

RESUMEN

Effective pandemic preparedness relies on anticipating viral mutations that are able to evade host immune responses to facilitate vaccine and therapeutic design. However, current strategies for viral evolution prediction are not available early in a pandemic-experimental approaches require host polyclonal antibodies to test against1-16, and existing computational methods draw heavily from current strain prevalence to make reliable predictions of variants of concern17-19. To address this, we developed EVEscape, a generalizable modular framework that combines fitness predictions from a deep learning model of historical sequences with biophysical and structural information. EVEscape quantifies the viral escape potential of mutations at scale and has the advantage of being applicable before surveillance sequencing, experimental scans or three-dimensional structures of antibody complexes are available. We demonstrate that EVEscape, trained on sequences available before 2020, is as accurate as high-throughput experimental scans at anticipating pandemic variation for SARS-CoV-2 and is generalizable to other viruses including influenza, HIV and understudied viruses with pandemic potential such as Lassa and Nipah. We provide continually revised escape scores for all current strains of SARS-CoV-2 and predict probable further mutations to forecast emerging strains as a tool for continuing vaccine development ( evescape.org ).


Asunto(s)
Evolución Molecular , Predicción , Evasión Inmune , Mutación , Pandemias , Virus , Humanos , Diseño de Fármacos , Infecciones por VIH , Evasión Inmune/genética , Evasión Inmune/inmunología , Gripe Humana , Virus Lassa , Virus Nipah , SARS-CoV-2/genética , SARS-CoV-2/inmunología , Vacunas Virales/inmunología , Virus/genética , Virus/inmunología
2.
J Shoulder Elbow Surg ; 33(7): 1503-1511, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38182017

RESUMEN

BACKGROUND: Reproducible methods for determining adequate bone densities for stemless anatomic total shoulder arthroplasty (aTSA) are currently lacking. The purpose of this study was to evaluate the utility of preoperative computed tomography (CT) imaging for assessing the bone density of the proximal humerus for supportive differentiation in the decision making for stemless humeral component implantation. It was hypothesized that preoperative 3-dimensional (3-D) CT bone density measures provide objective classifications of the bone quality for stemless aTSA. METHODS: A 3-part study was performed that included the analysis of cadaveric humerus CT scans followed by retrospective application to a clinical cohort and classification with a machine learning model. Thirty cadaveric humeri were evaluated with clinical CT and micro-CT (µCT) imaging. Phantom-calibrated CT data were used to extract 3-D regions of interest and defined radiographic scores. The final image processing script was applied retrospectively to a clinical cohort (n = 150) that had a preoperative CT and intraoperative bone density assessment using the "thumb test," followed by placement of an anatomic stemmed or stemless humeral component. Postscan patient-specific calibration was used to improve the functionality and accuracy of the density analysis. A machine learning model (Support vector machine [SVM]) was utilized to improve the classification of bone densities for a stemless humeral component. RESULTS: The image processing of clinical CT images demonstrated good to excellent accuracy for cylindrical cancellous bone densities (metaphysis [ICC = 0.986] and epiphysis [ICC = 0.883]). Patient-specific internal calibration significantly reduced biases and unwanted variance compared with standard HU CT scans (P < .0001). The SVM showed optimized prediction accuracy compared with conventional statistics with an accuracy of 73.9% and an AUC of 0.83 based on the intraoperative decision of the surgeon. The SVM model based on density clusters increased the accuracy of the bone quality classification to 87.3% with an AUC of 0.93. CONCLUSIONS: Preoperative CT imaging allows accurate evaluation of the bone densities in the proximal humerus. Three-dimensional regions of interest, rescaling using patient-specific calibration, and a machine learning model resulted in good to excellent prediction for objective bone quality classification. This approach may provide an objective tool extending preoperative selection criteria for stemless humeral component implantation.


Asunto(s)
Artroplastía de Reemplazo de Hombro , Densidad Ósea , Húmero , Imagenología Tridimensional , Tomografía Computarizada por Rayos X , Humanos , Artroplastía de Reemplazo de Hombro/métodos , Tomografía Computarizada por Rayos X/métodos , Estudios Retrospectivos , Masculino , Femenino , Húmero/diagnóstico por imagen , Húmero/cirugía , Anciano , Persona de Mediana Edad , Cadáver , Cuidados Preoperatorios/métodos , Aprendizaje Automático , Articulación del Hombro/diagnóstico por imagen , Articulación del Hombro/cirugía , Anciano de 80 o más Años
3.
Pneumologie ; 77(11): 907-915, 2023 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-37963480

RESUMEN

Care of patients with pulmonary arterial hypertension (PAH) needs a multi-facetet concept and measures, including management of adverse reactions, right heart insufficiency as well as information on pregnancy, travels by air, psychosocial support, physical exercise training and prophylaxis by vaccination.Positive study results led to an higher recommendation of specialized exercise training in pulmonary hypertension. Also, the recommendation on iron substitution was amended according to the current evidence.In the current guidelines, special focus was given to the elaboration of recommendations regarding pregnancy, including patient information, contraception and patient management in case of pregnancy.This article aims to provide an overview on the recommendations of general measuremes, special circumstances and patient management according to the ESC/ERS guidelines. Amendments to the guideline recommendations are given as comments from the authors of this article.


Asunto(s)
Insuficiencia Cardíaca , Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Embarazo , Femenino , Humanos , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/terapia , Ejercicio Físico
4.
Am J Nephrol ; 53(7): 552-564, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35675794

RESUMEN

INTRODUCTION: Chronic activation of the mineralocorticoid receptor (MR) leads to pathological processes like inflammation and fibrosis during cardiorenal disease. Modulation of immunological processes in the heart or kidney may serve as a mechanistic and therapeutic interface in cardiorenal pathologies. In this study, we investigated anti-inflammatory/-fibrotic and immunological effects of the selective nonsteroidal MR antagonists finerenone (FIN) in the deoxycorticosterone acetate (DOCA)-salt model. METHODS: Male C57BL6/J mice were uninephrectomized and received a DOCA pellet implantation (2.4 mg/day) plus 0.9% NaCl in drinking water (DOCA-salt) or received a sham operation and were orally treated with FIN (10 mg/kg/day) or vehicle in a preventive study design. Five weeks after the procedure, blood pressure (BP), urinary albumin/creatinine ratio (UACR), glomerular and tubulointerstitial damage, echocardiographic cardiac function, as well as cardiac/renal inflammatory cell content by FACS analysis were assessed. RESULTS: BP was significantly reduced by FIN. FACS analysis revealed a notable immune response due to DOCA-salt exposure. Especially, infiltrating renal RORγt γδ-positive T cells were upregulated, which was significantly ameliorated by FIN treatment. This was accompanied by a significant reduction of UACR in FIN-treated mice. In the heart, FIN reduced DOCA-salt-induced cardiac hypertrophy, cardiac fibrosis and led to an improvement of the global longitudinal strain. Cardiac actions of FIN were not associated with a regulation of cardiac RORγt γδ-positive T cells. DISCUSSION/CONCLUSION: The present study shows cardiac and renal protective effects of FIN in a DOCA-salt model. The cardiorenal protection was accompanied by a reduction of renal RORγt γδ T cells. The observed actions of FIN may provide a potential mechanism of its efficacy recently observed in clinical trials.


Asunto(s)
Hipertensión Renal , Hipertensión , Naftiridinas , Linfocitos T , Animales , Presión Sanguínea , Acetato de Desoxicorticosterona , Fibrosis , Hipertensión/tratamiento farmacológico , Hipertensión Renal/patología , Riñón/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Naftiridinas/farmacología , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/uso terapéutico
5.
Cardiovasc Ultrasound ; 17(1): 7, 2019 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-31010431

RESUMEN

Echocardiography is the most commonly applied technique for non-invasive assessment of cardiac function in small animals. Manual tracing of endocardial borders is time consuming and varies with operator experience. Therefore, we aimed to evaluate a novel automated two-dimensional software algorithm (Auto2DE) for small animals and compare it to the standard use of manual 2D-echocardiographic assessment (2DE). We hypothesized that novel Auto2DE will provide rapid and robust data sets, which are in agreement with manually assessed data of animals.2DE and Auto2DE were carried out using a high-resolution imaging-system for small animals. First, validation cohorts of mouse and rat cine loops were used to compare Auto2DE against 2DE. These data were stratified for image quality by a blinded expert in small animal imaging. Second, we evaluated 2DE and Auto2DE in four mouse models and four rat models with different cardiac pathologies.Automated assessment of LV function by 2DE was faster than conventional 2DE analysis and independent of operator experience levels. The accuracy of Auto2DE-assessed data in healthy mice was dependent on cine loop quality, with excellent agreement between Auto2DE and 2DE in cine loops with adequate quality. Auto2DE allowed for valid detection of impaired cardiac function in animal models with pronounced cardiac phenotypes, but yielded poor performance in diabetic animal models independent of image quality.Auto2DE represents a novel automated analysis tool for rapid assessment of LV function, which is suitable for data acquisition in studies with good and very good echocardiographic image quality, but presents systematic problems in specific pathologies.


Asunto(s)
Algoritmos , Ecocardiografía/métodos , Ventrículos Cardíacos/diagnóstico por imagen , Disfunción Ventricular Izquierda/diagnóstico , Función Ventricular Izquierda/fisiología , Animales , Modelos Animales de Enfermedad , Femenino , Ventrículos Cardíacos/fisiopatología , Masculino , Ratones , Ratas , Ratas Transgénicas , Reproducibilidad de los Resultados , Disfunción Ventricular Izquierda/fisiopatología
7.
Orthop J Sports Med ; 11(9): 23259671231201462, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37786477

RESUMEN

Background: A knotless, tensionable primary anterior cruciate ligament (ACL) repair system preloaded with an internal brace has been released. Currently, there is no biomechanical data on the stabilization and gap formation behavior of the adjustable system when compared with fixed repairs in human ACL tissue. Hypothesis: That knotless adjustable suture repair with an internal brace would provide overall higher construct stability and greater load share on the ACL with less gap formation compared with fixed repair. Study Design: Controlled laboratory study. Methods: Human cadaveric knees were utilized for internal braced ACL repair constructs (each group n = 16). Two fixed groups consisting of a single-cinch loop (SCL), cortical button (SCL group), and knotless suture-anchor (anchor group) were compared with an SCL-adjustable loop device (SCL-ALD) group. Testing was performed at 4 different peak loads (50, 150, 250, 350 N) over 4000 cycles at 0.75 Hz including suture repair preconditioning (10 cycles at 0.5 Hz) for SCL-ALD. Specimens were ultimately pulled to failure with a cut internal brace. The final loading situation of the construct and ACL repair with gap formation and ultimate strength were evaluated. Results: Peak elongation at various peak loads showed a significantly higher (P < .001) stabilization of SCL-ALD when compared with both fixed groups. There was a significantly higher (P < .001) load share of SCL-ALD, especially at lower loads (48% of 50 N), and the gap formation remained restricted up to 250 N. With only a little load share on the fixed constructs (<6%) at lower loads (50, 150 N), gap formation in these groups started at a load of 150 N, leading to significantly higher gaps (P < .001). The ultimate failure load for SCL-ALD and anchor groups was significantly increased (P < .001) as compared with SCL. The stiffness of SCL-ALD (62.9 ± 10.6 N/mm) was significantly increased (P < .001). Conclusion: Internal braced knotless adjustable fixation for ACL repair with preconditioning of the suture repaired ligament increased the overall stabilization with higher load share on the ACL and restricted gap formation (<0.5 mm up to 350 N) compared with fixed suture repair. All internal braced repairs restored stability according to native ACL function. Clinical Relevance: Adjustable ACL repair improved the mechanical characteristics and reduced gap formation, but the overall clinical significance on healing remains unclear.

8.
Am J Sports Med ; 51(11): 2858-2868, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37656204

RESUMEN

BACKGROUND: Reconstruction techniques for anterior glenoid bone loss have seen a trend from screws to suture-based fixations. However, comparative biomechanical data, including primary fixation and glenoid-graft contact pressure mapping, are limited. HYPOTHESIS: Suture-based bone block cerclage (BBC) and suspensory suture button (SB) techniques provide similar primary fixation and cyclic stability to double-screw fixation but with higher contact loading at the bony interface. STUDY DESIGN: Controlled laboratory study. METHODS: In total, 60 cadaveric scapulae were prepared to simulate anterior glenoid bone loss with coracoid autograft reconstruction. Graft fixation was performed with 3 different techniques: (1) an interconnected all-suture BBC, (2) 2 SB suspensions, and (3) 2 screws. Initial compression was analyzed during primary fixation. Cyclic peak loading with 50 N and 100 N over 250 cycles at 1 Hz was performed with a constant valley load of 25 N. Optical recording and pressure foils allowed for spatial bone block tracking and contact pressure mapping at the glenoid-graft interface. Load-to-failure testing was performed at a rate of 1.5 mm/s with ultimate load and stiffness measured. RESULTS: Initial graft compression was higher with screw fixation (141 ± 5 N) compared with suture-based fixations (P < .001), with BBC fixation providing significantly higher compression than SB fixation (116 ± 7 N vs. 91 ± 5 N; P < .001). Spatial bone block migration and ultimate failure load were similar between the BBC and screw groups. The SB group showed significantly increased bone block translation (3.1 ± 1.0 mm; P≤ .014) and rotation (2.5°± 1.4°; P≤ .025) and significantly lower ultimate failure load (180 ± 53 N) compared with the BBC (P = .046) and screw (P = .002) groups. Both suture-based fixations provided significantly increased graft-glenoid contact loading with higher pressure amplitudes (P≤ .032) and contact pressure after cyclic loading (+13%; SB: P = .007; BBC: P = .004) compared with screw fixation. CONCLUSION: Both SB and interconnected cerclage fixation improved dynamic contact loading compared with screw fixation in a biomechanical glenoid bone loss model. Cerclage fixation was biomechanically comparable with screw fixation but with a greater variability. SB fixation showed significantly lower primary fixation strength and greater bone block rotation and migration. CLINICAL RELEVANCE: Suture-based bone block fixations improved graft-glenoid contact loading, but the overall clinical consequence on healing remains unclear.


Asunto(s)
Procedimientos Ortopédicos , Escápula , Humanos , Escápula/cirugía , Suturas , Tornillos Óseos , Técnicas Histológicas
9.
bioRxiv ; 2023 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-38106144

RESUMEN

Predicting the effects of mutations in proteins is critical to many applications, from understanding genetic disease to designing novel proteins that can address our most pressing challenges in climate, agriculture and healthcare. Despite a surge in machine learning-based protein models to tackle these questions, an assessment of their respective benefits is challenging due to the use of distinct, often contrived, experimental datasets, and the variable performance of models across different protein families. Addressing these challenges requires scale. To that end we introduce ProteinGym, a large-scale and holistic set of benchmarks specifically designed for protein fitness prediction and design. It encompasses both a broad collection of over 250 standardized deep mutational scanning assays, spanning millions of mutated sequences, as well as curated clinical datasets providing high-quality expert annotations about mutation effects. We devise a robust evaluation framework that combines metrics for both fitness prediction and design, factors in known limitations of the underlying experimental methods, and covers both zero-shot and supervised settings. We report the performance of a diverse set of over 70 high-performing models from various subfields (eg., alignment-based, inverse folding) into a unified benchmark suite. We open source the corresponding codebase, datasets, MSAs, structures, model predictions and develop a user-friendly website that facilitates data access and analysis.

10.
Am J Sports Med ; 50(10): 2705-2713, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35787211

RESUMEN

BACKGROUND: Primary device fixation and the resistance against gap formation during repetitive loading influence the quality of meniscal repair. There are limited biomechanical data comparing primary tensioning and cyclic behavior of all-inside versus inside-out repair. HYPOTHESIS: All-inside devices provide higher initial load on the meniscal repair than inside-out fixation, and stiffer constructs show higher resistance against gap formation during cyclic loading. STUDY DESIGN: Controlled laboratory study. METHODS: In total, 60 longitudinal bucket-handle tears in human cadaveric menisci were created and repaired with a single stitch and randomly assigned to 4 all-inside groups (TrueSpan, FastFix 360, Stryker AIR, FiberStich) and 2 inside-out groups (suture repair [IO-S], suture tape [IO-ST]). Residual load after repair tensioning (50 N) and relief displacement were measured. Constructs underwent cyclic loading between 2 and 20 N over 500 cycles (0.75 Hz) with cyclic stiffness, gap formation, and final peak elongation measured. Ultimate load and stiffness were analyzed during pull to failure (3.15 mm/s). RESULTS: All-inside repair demonstrated significantly higher primary fixation strength than inside-out repair. The significantly highest load (mean ± SD; 20.1 ± 0.9 N; P < .037) and relief displacement (-2.40 ± 0.32 mm; P < .03) were for the knotless soft anchoring FiberStich group. The lowest initial load (9.0 ± 1.5 N; P < .001) and relief displacement (-1.39 ± 0.26 mm; P < .045) were for the IO-S repair group. The final gap formation (500th cycle) of FiberStich (0.75 ± 0.37 mm; P < .02) was significantly smaller than others and that of the IO-S (1.47 ± 0.33 mm; P < .045) significantly larger. The construct stiffness of the FiberStich and IO-ST groups was significantly greater at the end of cyclic testing (16.7 ± 0.80 and 15.5 ± 1.42 N/mm; P < .042, respectively) and ultimate failure testing (23.4 ± 3.6 and 20.6 ± 2.3 N/mm; P < .005). The FastFix 360 (86.4 ± 4.8 N) and Stryker AIR (84.4 ± 4.6 N) groups failed at a significantly lower load than the IO-S group (P < .02) with loss of anchor support. The FiberStich (146.8 ± 23.4 N), TrueSpan (142.0 ± 17.8 N), and IO-ST (139.4 ± 7.3 N) groups failed at significantly higher loads (P < .02) due to suture tearing. CONCLUSION: Overall, primary fixation strength of inside-out meniscal repair was significantly lower than all-inside repair in this cadaveric tissue model. Although absolute differences among groups were small, meniscal repairs with higher construct stiffness (IO-ST, FiberStich) demonstrated increased resistance against gap formation and failure load. CLINICAL RELEVANCE: Knotless single-stitch all-inside meniscal repair with a soft anchor resulted in less gapping, but the overall clinical significance on healing rates remains unclear.


Asunto(s)
Enfermedades de los Cartílagos , Traumatismos de la Rodilla , Lesiones de Menisco Tibial , Fenómenos Biomecánicos , Cadáver , Enfermedades de los Cartílagos/cirugía , Humanos , Traumatismos de la Rodilla/cirugía , Meniscos Tibiales/cirugía , Técnicas de Sutura , Lesiones de Menisco Tibial/cirugía
11.
Cardiovasc Res ; 118(11): 2488-2505, 2022 08 24.
Artículo en Inglés | MEDLINE | ID: mdl-34061169

RESUMEN

AIMS: Heart failure (HF) is characterized by an overactivation of ß-adrenergic signalling that directly contributes to impairment of myocardial function. Moreover, ß-adrenergic overactivation induces adipose tissue lipolysis, which may further worsen the development of HF. Recently, we demonstrated that adipose tissue-specific deletion of adipose triglyceride lipase (ATGL) prevents pressure-mediated HF in mice. In this study, we investigated the cardioprotective effects of a new pharmacological inhibitor of ATGL, Atglistatin, predominantly targeting ATGL in adipose tissue, on catecholamine-induced cardiac damage. METHODS AND RESULTS: Male 129/Sv mice received repeated injections of isoproterenol (ISO, 25 mg/kg BW) to induce cardiac damage. Five days prior to ISO application, oral Atglistatin (2 mmol/kg diet) or control treatment was started. Two and twelve days after the last ISO injection cardiac function was analysed by echocardiography. The myocardial deformation was evaluated using speckle-tracking-technique. Twelve days after the last ISO injection, echocardiographic analysis revealed a markedly impaired global longitudinal strain, which was significantly improved by the application of Atglistatin. No changes in ejection fraction were observed. Further studies included histological-, WB-, and RT-qPCR-based analysis of cardiac tissue, followed by cell culture experiments and mass spectrometry-based lipidome analysis. ISO application induced subendocardial fibrosis and a profound pro-apoptotic cardiac response, as demonstrated using an apoptosis-specific gene expression-array. Atglistatin treatment led to a dramatic reduction of these pro-fibrotic and pro-apoptotic processes. We then identified a specific set of fatty acids (FAs) liberated from adipocytes under ISO stimulation (palmitic acid, palmitoleic acid, and oleic acid), which induced pro-apoptotic effects in cardiomyocytes. Atglistatin significantly blocked this adipocytic FA secretion. CONCLUSION: This study demonstrates cardioprotective effects of Atglistatin in a mouse model of catecholamine-induced cardiac damage/dysfunction, involving anti-apoptotic and anti-fibrotic actions. Notably, beneficial cardioprotective effects of Atglistatin are likely mediated by non-cardiac actions, supporting the concept that pharmacological targeting of adipose tissue may provide an effective way to treat cardiac dysfunction.


Asunto(s)
Catecolaminas , Insuficiencia Cardíaca , Tejido Adiposo/metabolismo , Adrenérgicos/metabolismo , Adrenérgicos/farmacología , Animales , Catecolaminas/metabolismo , Lipasa/genética , Lipasa/metabolismo , Lipólisis , Masculino , Ratones , Compuestos de Fenilurea
12.
J Am Heart Assoc ; 10(14): e019473, 2021 07 20.
Artículo en Inglés | MEDLINE | ID: mdl-34227403

RESUMEN

Background It is known that dietary intake of polyunsaturated fatty acids may improve cardiac function. However, relatively high daily doses are required to achieve sufficient cardiac concentrations of beneficial omega-3 fatty acids. The liver X receptor (LXR) is a nuclear hormone receptor and a crucial regulator of lipid homeostasis in mammals. LXR activation has been shown to endogenously reprogram cellular lipid profiles toward increased polyunsaturated fatty acids levels. Here we studied whether LXR lipid reprogramming occurs in cardiac tissue and exerts cardioprotective actions. Methods and Results Male 129SV mice were treated with the LXR agonist AZ876 (20 µmol/kg per day) for 11 days. From day 6, the mice were injected with the nonselective ß-agonist isoproterenol for 4 consecutive days to induce diastolic dysfunction and subendocardial fibrosis while maintaining systolic function. Treatment with isoproterenol led to a marked impairment of global longitudinal strain and the E/e' ratio of transmitral flow to mitral annular velocity, which were both significantly improved by the LXR agonist. Histological examination showed a significant reduction in isoproterenol-induced subendocardial fibrosis by AZ876. Analysis of the cardiac lipid composition by liquid chromatography-high resolution mass spectrometry revealed a significant increase in cardiac polyunsaturated fatty acids levels and a significant reduction in saturated fatty acids by AZ876. Conclusions The present study provides evidence that the LXR agonist AZ876 prevents subendocardial damage, improves global longitudinal strain and E/e' in a mouse model of isoproterenol-induced cardiac damage, accompanied by an upregulation of cardiac polyunsaturated fatty acids levels. Cardiac LXR activation and beneficial endogenous cardiac lipid reprogramming may provide a new therapeutic strategy in cardiac disease with diastolic dysfunction.


Asunto(s)
Compuestos de Anilina/farmacología , Ácidos Grasos/metabolismo , Cardiopatías/prevención & control , Isoproterenol , Miocardio/metabolismo , Tiazoles/farmacología , Animales , Reprogramación Celular , Modelos Animales de Enfermedad , Fibrosis , Cardiopatías/inducido químicamente , Cardiopatías/patología , Receptores X del Hígado/agonistas , Masculino , Ratones , Ratones de la Cepa 129 , Miocardio/patología
13.
Orthop J Sports Med ; 8(1): 2325967119897421, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32064293

RESUMEN

BACKGROUND: Recently, there has been a resurgence of interest in primary repair of the anterior cruciate ligament (ACL), with fixation techniques evolving. However, to date, there have been no biomechanical studies comparing fixed to adjustable fixation repair techniques. HYPOTHESIS: Adjustable ACL repair provides for improved stabilization compared with fixed techniques with respect to both gap formation and residual load-bearing capability. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 4 different ACL repair techniques (n = 5 per group), including single- and double-cinch loop (CL) cortical button fixation as well as knotless single-suture anchor fixation, were tested using a porcine model. For adjustable single-CL loop fixation, additional preconditioning (10 cycles at 0.5 Hz) was performed. The force after fixation and the actuator displacement to achieve a time-zero preload of 10 N were measured for fixed techniques. Incrementally increasing cycling (1 mm/500 cycles) from 1 to 8 mm was performed for 4000 cycles at 0.75 Hz before pull to failure (50 mm/min). The final residual peak load and gap formation for each test block were analyzed as well as ultimate strength. RESULTS: Knot tying of a single-CL over a button (mean ± SD, 0.66 ± 0.23 mm) and knotless anchor fixation (0.20 ± 0.12 mm) resulted in significant time-zero gaps (P < .001) and significantly higher overall gap formation at reduced residual loading (analysis of covariance, P < .001) compared with both the double-CL loop and adjustable fixation techniques. The adjustable group showed the highest failure load and stiffness, at 305.7 N and 117.1 N/mm, respectively. The failure load of the knotted single-CL group was significantly reduced compared with all other groups (P < .001). CONCLUSION: Adjustable single-CL cortical button fixation with intraoperative preconditioning optimized time-zero ACL tension and led to significantly improved stabilization and reduced gap formation, with the highest ultimate strength. Single-CL loop knot tying over the button and knotless anchor fixation resulted in time-zero gaps to achieve slight tension on the ACL and significantly higher gap formation at reduced load-bearing capability. CLINICAL RELEVANCE: Although the clinical relevance of gap formation is uncertain, a biomechanical understanding of the stabilization potential of current ACL repair techniques is pertinent to the continued evolution of surgical approaches to enable better clinical outcomes.

14.
Orthop J Sports Med ; 8(1): 2325967119897423, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32064294

RESUMEN

BACKGROUND: The latest biomechanical studies on some form of internal bracing have shown improved stabilization for anterior cruciate ligament (ACL) repair, but gap formation and load-sharing function have not yet been reported. HYPOTHESIS: Internal bracing of an adjustable ACL repair construct provides improved stabilization with reduced gap formation and higher residual loading on the ACL. STUDY DESIGN: Controlled laboratory study. METHODS: Internally braced ACL repair constructs with single- and double-cinch loop (CL) cortical buttons, a knotless suture anchor, and a single-CL cortical button with adjustable loop fixation (CLS-ALD) were tested (n = 20 each) in a porcine model at 4 different loads (n = 5 each) over 4000 cycles at 0.75 Hz (n = 80 total). The CLS-ALD technique allowed for additional preconditioning (10 cycles at 0.5 Hz). Test results of the isolated internal brace groups served as a baseline for comparison. Lastly, specimens were pulled to failure (50 mm/min) with a cut internal brace. Final loading and gap formation on the ACL repair construct as well as ultimate strength were analyzed. RESULTS: A statistical significance for peak loads over peak elongation was found between the CLS-ALD and all other reinforced groups (analysis of covariance, P < .001). Accordingly, the adjustable repair technique showed improved load-bearing capability with the internal brace compared with all other fixed repair groups and revealed significantly higher loads than the knotted single-CL group. Also, significantly reduced gap formation was found for the CLS-ALD compared with all other groups (P < .001), with no gap formation up to 150 N with a final gap of 0.85 ± 0.31 mm at 350 N. A significantly higher ultimate failure load (866.2 ± 104.0 N; P < .001) was found for the button-fixed internal brace group compared with all other groups. CONCLUSION: Internal bracing had a crucial role in improving the stabilization potential of ACL repair at loads occurring during normal daily activity. The added strength of the internal brace allowed for reducing peak loads on the ACL repair construct as well as restricting gap formation to below 3 mm at loads up to 350 N. CLINICAL RELEVANCE: Improvements in the mechanical characteristics of current ACL repair techniques that enable reduced gap formation and allow for early range of motion and accelerated rehabilitation may strengthen the self-healing response with the formation of stable scar tissue.

15.
BMC Bioinformatics ; 10: 448, 2009 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-20038296

RESUMEN

BACKGROUND: The reconstruction of gene regulatory networks from time series gene expression data is one of the most difficult problems in systems biology. This is due to several reasons, among them the combinatorial explosion of possible network topologies, limited information content of the experimental data with high levels of noise, and the complexity of gene regulation at the transcriptional, translational and post-translational levels. At the same time, quantitative, dynamic models, ideally with probability distributions over model topologies and parameters, are highly desirable. RESULTS: We present a novel approach to infer such models from data, based on nonlinear differential equations, which we embed into a stochastic Bayesian framework. We thus address both the stochasticity of experimental data and the need for quantitative dynamic models. Furthermore, the Bayesian framework allows it to easily integrate prior knowledge into the inference process. Using stochastic sampling from the Bayes' posterior distribution, our approach can infer different likely network topologies and model parameters along with their respective probabilities from given data. We evaluate our approach on simulated data and the challenge #3 data from the DREAM 2 initiative. On the simulated data, we study effects of different levels of noise and dataset sizes. Results on real data show that the dynamics and main regulatory interactions are correctly reconstructed. CONCLUSIONS: Our approach combines dynamic modeling using differential equations with a stochastic learning framework, thus bridging the gap between biophysical modeling and stochastic inference approaches. Results show that the method can reap the advantages of both worlds, and allows the reconstruction of biophysically accurate dynamic models from noisy data. In addition, the stochastic learning framework used permits the computation of probability distributions over models and model parameters, which holds interesting prospects for experimental design purposes.


Asunto(s)
Biología Computacional/métodos , Regulación de la Expresión Génica , Redes Reguladoras de Genes/genética , Dinámicas no Lineales
16.
Microb Cell Fact ; 8: 42, 2009 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-19646274

RESUMEN

BACKGROUND: In industry and academic research, there is an increasing demand for flexible automated microfermentation platforms with advanced sensing technology. However, up to now, conventional platforms cannot generate continuous data in high-throughput cultivations, in particular for monitoring biomass and fluorescent proteins. Furthermore, microfermentation platforms are needed that can easily combine cost-effective, disposable microbioreactors with downstream processing and analytical assays. RESULTS: To meet this demand, a novel automated microfermentation platform consisting of a BioLector and a liquid-handling robot (Robo-Lector) was sucessfully built and tested. The BioLector provides a cultivation system that is able to permanently monitor microbial growth and the fluorescence of reporter proteins under defined conditions in microtiter plates. Three examplary methods were programed on the Robo-Lector platform to study in detail high-throughput cultivation processes and especially recombinant protein expression. The host/vector system E. coli BL21(DE3) pRhotHi-2-EcFbFP, expressing the fluorescence protein EcFbFP, was hereby investigated. With the method 'induction profiling' it was possible to conduct 96 different induction experiments (varying inducer concentrations from 0 to 1.5 mM IPTG at 8 different induction times) simultaneously in an automated way. The method 'biomass-specific induction' allowed to automatically induce cultures with different growth kinetics in a microtiter plate at the same biomass concentration, which resulted in a relative standard deviation of the EcFbFP production of only +/- 7%. The third method 'biomass-specific replication' enabled to generate equal initial biomass concentrations in main cultures from precultures with different growth kinetics. This was realized by automatically transferring an appropiate inoculum volume from the different preculture microtiter wells to respective wells of the main culture plate, where subsequently similar growth kinetics could be obtained. CONCLUSION: The Robo-Lector generates extensive kinetic data in high-throughput cultivations, particularly for biomass and fluorescence protein formation. Based on the non-invasive on-line-monitoring signals, actions of the liquid-handling robot can easily be triggered. This interaction between the robot and the BioLector (Robo-Lector) combines high-content data generation with systematic high-throughput experimentation in an automated fashion, offering new possibilities to study biological production systems. The presented platform uses a standard liquid-handling workstation with widespread automation possibilities. Thus, high-throughput cultivations can now be combined with small-scale downstream processing techniques and analytical assays. Ultimately, this novel versatile platform can accelerate and intensify research and development in the field of systems biology as well as modelling and bioprocess optimization.

17.
Clin Pract Cases Emerg Med ; 3(2): 137-139, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31061970

RESUMEN

Implantable collamer lenses (ICL) are phakic (natural lens remains in place) lenses that were first developed in the 1990s for correction of high myopia. The effectiveness and safety of ICLs are making them an increasingly popular option for vision correction in the myopic patient, competing with traditional options like glasses, contacts, and procedures such as laser-assisted in situ keratomileusis. Although generally safe, due to the position of the phakic ICL in the eye, pupillary block remains a rare but vision-threatening complication of ICL implantation. Pupillary block caused by phakic ICL is a serious complication that requires urgent recognition and intervention and is poorly described in emergency medicine literature. We describe a case of pupillary block five years after ICL implantation that was refractory to standard medical therapy, highlighting the importance of early diagnosis and referral for more definitive therapy.

18.
West J Emerg Med ; 20(1): 132-137, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30643616

RESUMEN

INTRODUCTION: The Association of American Medical Colleges has introduced the Standardized Video Interview (SVI) to assess the communication and professionalism skills of residency applicants to allow a more holistic view of applicants beyond academic performance. Initial data suggests scores are not correlated with academic performance and provide a new measure of applicant attributes. It is not currently known how the SVI compares to existing metrics for assessing communication and professionalism during the interview process. METHODS: Applicants to the University of Wisconsin Emergency Medicine Residency program were invited and interviewed without use of the SVI scores or videos. All faculty interviewers were blinded to applicants' SVI information and asked to rate each applicant on their communication and professionalism on a scale from 1-25 (faculty gestalt score), analogous to the 6-30 scoring used by the SVI. We transformed SVI scores to our 1-25 system (transformed SVI score) for ease of comparison and compared them to faculty gestalt scores as well as applicants' overall score for all components of their interview day (interview score). RESULTS: We collected data for 125 residency candidates. Each applicant received a faculty gestalt score from up to four faculty interviewers. There was no significant correlation of SVI scores with faculty gestalt scores (Spearman's rank correlation coefficient [rs] (123)=0.09, p=0.30) and no correlation with the overall interview score (rs(123)=0.01, p=0.93). Faculty gestalt scores were correlated positively with interview scores (rs(123)=0.65, p<0.01). CONCLUSION: SVI scores show no significant correlation with faculty gestalt scores of communication and professionalism. This could relate to bias introduced by knowledge of an applicant's academic performance, different types of questions being asked by faculty interviewers, or lack of uniform criteria by which faculty assess these competencies. Further research is needed to determine whether SVI scores or faculty gestalt correlate with performance during residency.


Asunto(s)
Comunicación , Internado y Residencia/normas , Selección de Personal/métodos , Profesionalismo , Grabación en Video , Evaluación Educacional/estadística & datos numéricos , Medicina de Emergencia/educación , Docentes , Humanos , Entrevistas como Asunto , Wisconsin
19.
Science ; 348(6233): 428-31, 2015 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-25745067

RESUMEN

Methane is a key component in the global carbon cycle, with a wide range of anthropogenic and natural sources. Although isotopic compositions of methane have traditionally aided source identification, the abundance of its multiply substituted "clumped" isotopologues (for example, (13)CH3D) has recently emerged as a proxy for determining methane-formation temperatures. However, the effect of biological processes on methane's clumped isotopologue signature is poorly constrained. We show that methanogenesis proceeding at relatively high rates in cattle, surface environments, and laboratory cultures exerts kinetic control on (13)CH3D abundances and results in anomalously elevated formation-temperature estimates. We demonstrate quantitatively that H2 availability accounts for this effect. Clumped methane thermometry can therefore provide constraints on the generation of methane in diverse settings, including continental serpentinization sites and ancient, deep groundwaters.


Asunto(s)
Ciclo del Carbono , Metano/biosíntesis , Methanomicrobiales/metabolismo , Animales , Isótopos de Carbono/química , Bovinos , Agua Subterránea/química , Hidrógeno/química , Metano/química , Temperatura
20.
Rev. bras. ciênc. vet ; 25(1): 36-39, jan./mar. 2018. il.
Artículo en Portugués | LILACS | ID: biblio-987927

RESUMEN

A produção e consumo de pescado vem crescendo nos últimos anos, com algumas espécies ganhando destaque no cenário nacional como o híbrido Colossoma macropomum X Piaractus brachypomum (tambatinga) e o Brycon microleps (piraputanga). Dados sobre a composição centesimal e teste aceitação são de suma importância para inferir sobre o potencial mercadológico dessas espécies. Sendo assim, o objetivo deste estudo foi disponibilizar dados relativos a composição centesimal, aceitação sensorial, com escala hedônica estruturada de 9 pontos, intenção de compra dos consumidores e inferir em questões relacionadas a métodos adequados de conservação, possíveis alterações degradativas e potencial mercadológico. Resultados relacionados a composição das espécies estudas (p<0,05) demonstram não haver diferença significativa nos valores de umidade e cinzas, enquanto que o teor de proteínas e lipídeos e consequente valor calórico foram mais elevados nos exemplares de piraputanga; o teor mais elevado de carboidratos foi observado nos exemplares de tambatinga. No teste de aceitação (p<0,05), os atributos aparência, cor e suculência foram melhor avaliados nos exemplares de tambatinga quando comparados aos de piraputanga. Entretanto, com os valores obtidos pode-se inferir que ambas espécies constituem alternativas de elevado valor nutricional ao consumidor além de apresentarem boa aceitação com aproximadamente 60% dos julgadores demonstrando intenção na compra das espécies.


The production and fish consumption has been growing in recent years, with some species gaining prominence on the national scene as hybrid Colossoma macropomum X Piaractus brachypomum (tambatinga) and Brycon microleps (piraputanga). Data on proximate composition and test acceptance are of paramount importance to infer about the market potential of these species. Thus, the aim of this study was to provide data on the chemical composition, sensory acceptance by hedonic scale of 9 points, consumer purchase intent and infer on issues related to adequate conservation methods, possible degradative and market potential changes. Results related to composition of the species studied (p<0,05) showed no significant difference in the values of moisture and ash, while the protein, lipid and consequent caloric value were higher in specimens of piraputanga; the highest carbohydrate content was observed in tambatinga copies. In acceptance testing (p<0,05), the attributes appearance, color and juiciness were better evaluated in specimens of tambatinga when compared to piraputanga. However, with the values obtained can be inferred that both species are alternatives of high nutritional value to the consumer in addition to having good acceptance with approximately 60% of the judges demonstrating intention in buying the species.


Asunto(s)
Animales , Ingestión de Alimentos , Producción de Alimentos
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