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1.
J Orthop Sci ; 27(3): 514-532, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-34922804

RESUMEN

BACKGROUND: The guidelines presented herein provide recommendations for the management of patients with lateral epicondylitis of the humerus. These recommendations are endorsed by the Japanese Orthopaedic Association (JOA) and Japan Elbow Society. METHODS: The JOA lateral epicondylitis guideline committee revised the previous guidelines on the basis of the "Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014", which emphasized the importance of the balance between benefit and harm, and proposed a desirable method for preparing clinical guidelines in Japan. These guidelines consist of 11 clinical questions (CQs), 9 background questions (BQs), and 3 future research questions (FRQs). For each CQ, outcomes from the literature were collected and evaluated systematically according to the adopted study design. RESULTS: The committee proposed recommendations for each CQ by determining the level of evidence and assessing the consensus rate. Physical therapy was the best recommendation with the best evidence. The BQs and FRQs were answered by collecting evidence based on the literature. CONCLUSIONS: The guidelines presented herein were reviewed systematically, and recommendations were proposed for each CQ. These guidelines are expected to be widely used not only by surgeons or physicians but also by other healthcare providers, such as nurses, therapists, and athletic trainers.


Asunto(s)
Codo de Tenista , Humanos , Húmero/cirugía , Japón , Codo de Tenista/diagnóstico , Codo de Tenista/terapia
2.
Eur Radiol ; 31(8): 5721-5733, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33454801

RESUMEN

OBJECTIVES: We developed a novel method to create three-dimensional magnetic resonance imaging-CT (3D MRI-CT) fusion images for detailed lesion evaluation and surgical simulation in capitellar osteochondritis dissecans (COCD). This study aimed to clarify its usefulness. METHODS: We enrolled 12 boys with COCD (mean age, 13.8 years) and preoperatively constructed 3D models of the humerus and articular cartilage from MR images obtained with a 3-T imager. For better visualization of the articular cartilage outline, we applied 7 kg of axial traction to the elbow during MRI. We also constructed a 3D model of the humerus from CT images. 3D MRI-CT fusion images were created using both models. The average distance difference between two corresponding points as per the 3D CT and 3D MRI models of the humerus was evaluated. Using the 3D MRI-CT fusion images, we measured longitudinal and transverse lesion diameters; evaluated articular cartilage fissures and defects, articular surface deformities, and the International Cartilage Repair Society (ICRS) classification; and validated the results using intraoperative findings. RESULTS: The mean average distance difference was 0.75 mm. The 3D MRI-CT fusion images accurately reproduced lesion conditions in every case and correctly predicted the ICRS classification with 100% accuracy. Preoperatively measured longitudinal and transverse lesion diameters were not significantly different from intraoperative measurements (p = 0.79, 0.32 respectively). CONCLUSION: 3D MRI-CT fusion images provide a detailed evaluation of COCD lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone. KEY POINTS: • We developed a novel method to create three-dimensional magnetic resonance imaging-computed tomography (3D MRI-CT) fusion images for the evaluation of capitellar osteochondritis dissecans. • 3D MRI-CT fusion images enabled the accurate prediction of lesions and provided a detailed evaluation of lesion severity by presenting the exact positional relationship between the articular cartilage and subchondral bone.


Asunto(s)
Cartílago Articular , Articulación del Codo , Osteocondritis Disecante , Adolescente , Cartílago Articular/diagnóstico por imagen , Cartílago Articular/cirugía , Humanos , Imagen por Resonancia Magnética , Masculino , Osteocondritis Disecante/diagnóstico por imagen , Osteocondritis Disecante/cirugía , Tomografía Computarizada por Rayos X
3.
Proc Natl Acad Sci U S A ; 113(26): 7035-40, 2016 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-27298351

RESUMEN

This article proposes a topological method that extracts hierarchical structures of various amorphous solids. The method is based on the persistence diagram (PD), a mathematical tool for capturing shapes of multiscale data. The input to the PDs is given by an atomic configuration and the output is expressed as 2D histograms. Then, specific distributions such as curves and islands in the PDs identify meaningful shape characteristics of the atomic configuration. Although the method can be applied to a wide variety of disordered systems, it is applied here to silica glass, the Lennard-Jones system, and Cu-Zr metallic glass as standard examples of continuous random network and random packing structures. In silica glass, the method classified the atomic rings as short-range and medium-range orders and unveiled hierarchical ring structures among them. These detailed geometric characterizations clarified a real space origin of the first sharp diffraction peak and also indicated that PDs contain information on elastic response. Even in the Lennard-Jones system and Cu-Zr metallic glass, the hierarchical structures in the atomic configurations were derived in a similar way using PDs, although the glass structures and properties substantially differ from silica glass. These results suggest that the PDs provide a unified method that extracts greater depth of geometric information in amorphous solids than conventional methods.

4.
J Orthop Sci ; 24(2): 195-199, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30424927

RESUMEN

BACKGROUND: In infant poliomyelitis or poliomyelitis-like paresis, there has been no means of treating residual paralysis and the policy has been to wait until an affected infant has grown sufficiently to enable tendon transfer or arthrodesis. However, recent reports have described relatively good results for early surgical intervention in the form of nerve transfer. METHODS: In a 4-year and 6-month-old child we transferred a partial ulnar nerve for elbow flexor reconstruction even 3 years and 10 months after the onset of poliomyelitis-like palsy and also transferred partial accessory and radial nerves for shoulder function restoration 6 months after the first operation. RESULTS: Elbow flexor restored M4 on the British Medical Research Council scale. The shoulder subluxation resolved, however, the strengths of the deltoid and infraspinatus remained almost M1. At the most recent clinical examination, the patient was 18 years old and the active range of motion of patient's left elbow was 0°-125°, and those of the whole shoulder girdle were abduction 35°, flexion 60°, extension 30° and external rotation 0°. CONCLUSIONS: The outcomes we achieved may support partial nerve transfer techniques as viable treatment options for persistent long-standing motor deficits following poliomyelitis-like palsy in children. However, we recommend performing partial nerve transfer as early as possible after recovery from flaccid paralysis and also use of nerves that derive from narrow spinal cord segments. After denervation, children's neuromuscular systems seem to have the ability to regenerate after a much longer period than has generally been believed. This speculation is based on only a single case report; thus, more experience is needed before this generalization can confidently be made.


Asunto(s)
Neuropatías del Plexo Braquial/cirugía , Articulación del Codo/fisiopatología , Regeneración Nerviosa/fisiología , Transferencia de Nervios/métodos , Poliomielitis/complicaciones , Articulación del Hombro/fisiopatología , Neuropatías del Plexo Braquial/diagnóstico por imagen , Neuropatías del Plexo Braquial/etiología , Preescolar , Femenino , Estudios de Seguimiento , Hospitales Universitarios , Humanos , Lactante , Poliomielitis/diagnóstico , Nervio Radial/cirugía , Nervio Radial/trasplante , Rango del Movimiento Articular/fisiología , Recuperación de la Función , Factores de Tiempo , Resultado del Tratamiento , Nervio Cubital/cirugía , Nervio Cubital/trasplante
5.
J Orthop Sci ; 22(3): 430-433, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28325700

RESUMEN

PURPOSE: Needle electromyography provides essential information about the functional aspects of the muscle. But little attention has been given in the literature to needle electromyography examinations in carpal tunnel syndrome. We examined the relationship between preoperative needle electromyography findings and functional recovery of the abductor pollicis brevis (APB) muscle in severe carpal tunnel syndrome patients. METHODS: The subjects of this study were 49 patients, 58 hands, who fit the following 5 criteria: (1) idiopathic carpal tunnel syndrome; (2) pre-op MMT grade of the APB muscle was M0 or M1; (3) APB-CMAP (compound muscle action potential) was not evoked in a median nerve conduction study; (4) needle electromyography of the APB muscle had been done; (5) underwent carpal tunnel release only. The patients were divided into two groups according to the results of pre-op needle electromyography: voluntary motor unit potential of the APB muscle was evoked [MUP(+) group]or not [MUP(-) group]. We evaluated APB muscle strength at one year after surgery, and patient satisfaction and functional evaluations (CTSI-FS) at more than one year after. RESULTS: The APB muscle recovery rate to M3 or higher was 100% in the MUP(+) group, and 57% in the MUP(-) group. Patient satisfaction was also high and functional recovery was sufficient in the MUP(+) group. No patients requested a second opponensplasty. CONCLUSION: Our findings suggest that post-op restoration of thumb function relates to whether or not the MUP ofthe APB muscle is evoked. Single-stage opponensplasty may be unnecessary if the MUP of the APB muscle is; evoked. Needle electromyography is therefore useful in consideration for opponensplasty. LEVEL OF EVIDENCE: Level Ⅲ, case-control study.


Asunto(s)
Síndrome del Túnel Carpiano/diagnóstico , Electromiografía/instrumentación , Nervio Mediano/fisiopatología , Fuerza Muscular/fisiología , Músculo Esquelético/fisiopatología , Conducción Nerviosa/fisiología , Procedimientos Neuroquirúrgicos/métodos , Potenciales de Acción/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Síndrome del Túnel Carpiano/fisiopatología , Síndrome del Túnel Carpiano/cirugía , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Músculo Esquelético/inervación , Agujas , Satisfacción del Paciente , Periodo Posoperatorio , Periodo Preoperatorio , Recuperación de la Función , Estudios Retrospectivos , Índice de Severidad de la Enfermedad
6.
J Theor Biol ; 395: 227-237, 2016 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-26845309

RESUMEN

The ability to continue flowering after loss of inductive environmental cues that trigger flowering is termed floral commitment. Reversible transition involving a switch from floral development back to vegetative development has been found in Arabidopsis mutants and many plant species. Although the molecular basis for floral commitment remains unclear, recent studies suggest that the persistent activity of FLOWERING LOCUS T (FT) at inflorescences is required for floral commitment in Arabidopsis thaliana. Because FT encodes a mobile signal, florigen, which is generally transported from leaves to meristems through the phloem, understanding the transportation dynamics of FT is required to explore the role of FT on floral commitment. Here we developed a transportation model of leaf- and inflorescence-derived florigen and sucrose based on pressure-flow hypothesis. Depending on the demanded level of florigen supply for floral commitment of each floral meristem, the model predicted the change in inflorescence pattern from stable commitment to flower, transient flowering, and complete reversion. FT activity in inflorescence partly suppressed floral reversion, but complete suppression was achieved only when inflorescence became a source of sucrose. This finding highlights the importance of monitoring the spatio-temporal sucrose distribution and floral stimulus to understand inflorescence development mechanism.


Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Florigena/metabolismo , Modelos Biológicos , Floema/metabolismo , Hojas de la Planta/metabolismo , Transporte Biológico Activo/fisiología
7.
Soft Matter ; 12(27): 5905-14, 2016 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-27337660

RESUMEN

We numerically study a set of coupled Cahn-Hilliard equations as a means to find morphologies of diblock copolymers in three-dimensional spherical confinement. This approach allows us to find a variety of energy minimizers including rings, tennis balls, Janus balls and multipods among several others. Phase diagrams of confined morphologies are presented. We modify the size of the interface between microphases to control the number of holes in multipod morphologies. Comparison to experimental observation by transmission electron microtomography of multipods in polystyrene-polyisoprene diblock copolymers is also presented.

8.
Soft Matter ; 12(40): 8448, 2016 10 12.
Artículo en Inglés | MEDLINE | ID: mdl-27714344

RESUMEN

Correction for 'Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn-Hilliard equations' by Edgar Avalos et al., Soft Matter, 2016, 12, 5905-5914.

9.
Nanotechnology ; 26(30): 304001, 2015 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-26150288

RESUMEN

The characterization of the medium-range (MRO) order in amorphous materials and its relation to the short-range order is discussed. A new topological approach to extract a hierarchical structure of amorphous materials is presented, which is robust against small perturbations and allows us to distinguish it from periodic or random configurations. This method is called the persistence diagram (PD) and introduces scales to many-body atomic structures to facilitate size and shape characterization. We first illustrate the representation of perfect crystalline and random structures in PDs. Then, the MRO in amorphous silica is characterized using the appropriate PD. The PD approach compresses the size of the data set significantly, to much smaller geometrical summaries, and has considerable potential for application to a wide range of materials, including complex molecular liquids, granular materials, and metallic glasses.

10.
Phys Chem Chem Phys ; 17(14): 9148-52, 2015 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-25757627

RESUMEN

The photo-sensitive Belousov-Zhabotinsky (BZ) reaction system was investigated to understand the response of wave propagation to local pulse stimulation in an excitable field. When the chemical wave was irradiated with a bright pulse or a dark pulse, the speed of wave propagation decreased or increased. The timing of pulse irradiation that significantly affected the speed of chemical wave propagation was different with the bright and dark pulses. That is, there is a sensitive point in the chemical wave. The experimental results were qualitatively reproduced by a numerical calculation based on a three-variable Oregonator model that was modified for the photosensitive BZ reaction. These results suggest that the chemical wave is sensitive to the timing of pulse irradiation due to the rates of production of an activator and an inhibitor in the photochemical reaction.


Asunto(s)
Simulación por Computador , Modelos Teóricos , Fotoquímica , Rutenio/química , Catálisis
11.
ACS Omega ; 9(15): 17276-17288, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38645350

RESUMEN

This study delves into the formation of nanoscale polyhedral block copolymer particles (PBCPs) exhibiting cubic, octahedral, and variant geometries. These structures represent a pioneering class that has never been fabricated previously. PBCP features distinct variations in curvature on the outer surface, aligning with the edges and corners of polyhedral shapes. This characteristic sharply contrasts with previous block copolymers (BCPs), which displayed a smooth spherical surface. The emergence of these cornered morphologies presents an intriguing and counterintuitive phenomenon and is linked to process parameters, such as evaporation rates and initial concentration, while keeping other variables constant. Using a system of coupled Cahn-Hillard (CCH) equations, we uncover the mechanisms driving polyhedral particle formation, emphasizing the importance of controlling relaxation parameters for shape variable u and microphase separation v. This unconventional approach, differing from traditional steepest descent method, allows for precise control and diverse polyhedral particle generation. Accelerating the shape variable u proves crucial for expediting precipitation and aligns with experimental observations. Employing the above theoretical model, we achieve shape predictions for particles and the microphase separation within them, which overcomes the limitations of ab initio computations. Additionally, a numerical stability analysis discerns the transient nature versus local minimizer characteristics. Overall, our findings contribute to understanding the complex interplay between process variables and the morphology of polyhedral BCP nanoparticles.

12.
J Orthop Sci ; 18(2): 230-7, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23114859

RESUMEN

BACKGROUND: The purpose of this study was to investigate the midterm clinical and radiographic outcomes of this new treatment for Kienböck's disease. METHODS: We applied a new method involving drilling, bone marrow transfusion, external fixation, and low-intensity pulsed ultrasound for patients with Kienböck's disease. Between 2000 and 2006, the treatment was performed in 18 patients (10 men and 8 women; 9 right wrists and 9 left wrists). The preoperative Lichtman stages were stage II in 4 cases, stage IIIa in 11 cases, and stage IIIb in 3 cases. The mean age at surgery was 44.9 years (range 16-68 years), and the mean follow-up period was 63 months (range 28-125 months). The overall results were evaluated using the Mayo wrist score and Nakamura scoring system for Kienböck's disease. Magnetic resonance imaging (MRI) was performed for all patients. RESULTS: Wrist pain improved to no pain in 13 patients, mild pain in 4 patients, and moderate pain in 1 patient. The average wrist flexion-extension arc was 100° and averaged 120 % of the preoperative value. The average grip strength increased from 50 to 85 % relative to the unaffected side. On roentgenograms, the carpal height ratio (change from 0.53 to 0.51) and the Stahl index (change from 0.38 to 0.32) decreased slightly. On MRI, fatty marrow was recovered in 11 patients (61 %) on proton density-weighted images. CONCLUSIONS: This method can be used as a less-invasive surgical treatment alternative for Kienböck's disease. At an average follow-up period of 6 years, this new treatment has been shown to be a reliable and durable procedure for patients with Lichtman stage II or stage III Kienböck's disease. Caution should be exercised for patients with a fragmented lunate because of the risk of collapse and nonunion of the lunate.


Asunto(s)
Trasplante de Médula Ósea , Fijadores Externos , Osteonecrosis/terapia , Terapia por Ultrasonido , Adolescente , Adulto , Anciano , Terapia Combinada , Femenino , Fuerza de la Mano , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Osteonecrosis/patología , Dimensión del Dolor , Resultado del Tratamiento
13.
J Orthop Sci ; 18(5): 712-9, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23749174

RESUMEN

BACKGROUND: The patient-rated elbow evaluation (PREE) is a joint-specific, self-administered questionnaire consisting of a pain scale (PREE-P) and a functional scale (PREE-F), the latter consisting of specific function (PREE-SF) and usual function (PREE-UF). The purpose of this study was to cross-culturally adapt the PREE into Japanese (PREE-J) and to test its reliability, validity, and responsiveness. METHODS: A consecutive series of 74 patients with elbow disorder completed the PREE-J, the Japanese version of the disabilities of the arm, shoulder, and hand (DASH-JSSH) questionnaire, and the official Japanese version of the 36-Item Short-Form Health Survey (SF-36). Of the 74 patients, 53 were reassessed for test-retest reliability 1 or 2 weeks later. Reliability was investigated in terms of reproducibility and internal consistency. The validity of the PREE-J was examined by factor analysis, and correlation coefficients were obtained using the PREE-J, DASH-JSSH, and SF-36. Responsiveness was examined by calculating the standardized response mean (SRM) and effect size after elbow surgery in 53 patients. RESULTS: Cronbach's α coefficients for PREE-P, PREE-F, and PREE were 0.92, 0.97, and 0.97, respectively, and the corresponding intraclass correlation coefficients were 0.92, 0.93, and 0.94, respectively. Unidimensionality of PREE-P and PREE-F was confirmed by factor analysis. The coefficients of correlation between PREE-P and PREE-F or DASH-JSSH were 0.81 and 0.74, respectively; that between PREE-F and DASH-JSSH was 0.86, and those between DASH-JSSH and PREE-SF or PREE-UF were 0.85 and 0.82, respectively. Moderate correlation was observed in "physical functioning" for SF-36 and PREE-F (r = -0.69) or PREE (r = -0.68). The SRMs/effect sizes of PREE-P (1.31/1.32) or PREE (1.28/1.12) were more responsive than the DASH-JSSH (0.99/0.85), "bodily pain" (-1.15/-1.43), and "physical functioning" (-0.70/-0.44) in SF-36. CONCLUSION: The PREE-J represents a reliable, valid, and responsive instrument and has evaluation capacities equivalent to those of the original PREE.


Asunto(s)
Autoevaluación Diagnóstica , Articulación del Codo , Artropatías/diagnóstico , Adulto , Codo , Femenino , Humanos , Japón , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Encuestas y Cuestionarios
14.
J Hand Surg Am ; 37(1): 83-9, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22054982

RESUMEN

PURPOSE: Diagnosis and treatment remain controversial for Kienböck disease. A few reports have correlated magnetic resonance imaging (MRI), which is essential for early diagnosis, and histopathology of Kienböck biopsy specimens, but histopathological correlations of whole lunate bones or histological slices compared with MRI images are lacking. The purpose of this study was to compare presurgical MRI scans with corresponding histological slices of Kienböck-diseased lunates. METHODS: We excised whole lunates at the time of surgery from 6 patients with Kienböck disease (stage IIIB) undergoing tendon-ball replacement or a Graner procedure. We stained paraffin-embedded, coronally sectioned specimens with hematoxylin-eosin and compared them with presurgical coronal scans using MRI with a 47-mm microscopy surface coil. RESULTS: Toward the center of the lunates, the signal intensity in the proton density-weighted images was reduced, whereas the dorsal and palmar sides of the lunates exhibited no changes in intensity. In correlation, histopathological findings revealed strongly disrupted trabeculae toward the center of the lunates and intact trabeculae in the dorsal side of the lunates. Likewise, the necrotic and vitalized bone exhibited low and high signal intensities, respectively, in the proton density-weighted images; however, in the fast-field echo images, there were no correlations with histopathological observations. CONCLUSIONS: Proton density-weighted MRIs but not fast-field echo images using a 47-mm microscopy coil reflected the extent and localization of the necrotic area in Kienböck-diseased lunates, as evidenced by comparison with histological analyses of the lunate specimens. CLINICAL RELEVANCE: Proton density-weighted MRIs accurately reflect the vascular status of the lunate and may help plan treatment on a case-by-case basis.


Asunto(s)
Hueso Semilunar/patología , Imagen por Resonancia Magnética/métodos , Osteonecrosis/diagnóstico , Osteonecrosis/cirugía , Adulto , Biopsia con Aguja , Femenino , Humanos , Inmunohistoquímica , Hueso Semilunar/cirugía , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios/métodos , Estudios Retrospectivos , Muestreo , Sensibilidad y Especificidad , Adulto Joven
15.
J Hand Surg Eur Vol ; 47(4): 399-404, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34713748

RESUMEN

We described a reconstruction method for restoring hook grip function of the fingers in patients with total brachial plexus injury. The paralysed latissimus dorsi muscle was transferred to the upper limb as a pedicle flap and sutured to the flexor digitorum profundus tendons. The muscle was then reanimated with two intercostal donor nerves to the thoraco-dorsal nerve. Fourteen young adult patients (mean 23 years, range 17 to 32 years) with traumatic brachial plexus injury who underwent reconstruction using this technique from 2000 to 2019. After mean follow-up of 65 months (range 20 to 170), finger flexion of strength greater than or equal to M3 was achieved in 10 of the 14 patients. The mean weight that could be lifted using a hook grip was 2.6 kg, and that which could be lifted with both hands was 4.1 kg. The intercostal nerve-innervated latissimus dorsi muscle transfer can provide useful hook grip hand function without the need to sacrifice donor vessels or healthy muscles.Level of evidence: IV.


Asunto(s)
Neuropatías del Plexo Braquial , Plexo Braquial , Transferencia de Nervios , Músculos Superficiales de la Espalda , Plexo Braquial/lesiones , Neuropatías del Plexo Braquial/cirugía , Dedos/cirugía , Fuerza de la Mano , Humanos , Transferencia de Nervios/métodos , Resultado del Tratamiento , Adulto Joven
16.
Phys Rev E ; 104(1-1): 014505, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34412273

RESUMEN

We investigate the solution landscapes of the confined diblock copolymer and homopolymer in two-dimensional domain by using the extended Ohta-Kawasaki model. The projection saddle dynamics method is developed to compute the saddle points with mass conservation and construct the solution landscape by coupling with downward and upward search algorithms. A variety of stationary solutions are identified and classified in the solution landscape, including Flower class, Mosaic class, Core-shell class, and Tai-chi class. The relationships between different stable states are shown by either transition pathways connected by index-1 saddle points or dynamical pathways connected by a high-index saddle point. The solution landscapes also demonstrate the symmetry-breaking phenomena, in which more solutions with high symmetry are found when the domain size increases.

17.
Diagnostics (Basel) ; 11(12)2021 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-34943574

RESUMEN

We used our novel three-dimensional magnetic resonance imaging-computed tomography fusion images (3D MRI-CT fusion images; MCFIs) for detailed preoperative lesion evaluation and surgical simulation in osteochondritis dissecans (OCD) of the elbow. Herein, we introduce our procedure and report the findings of the assessment of its utility. We enrolled 16 men (mean age: 14.0 years) and performed preoperative MRI using 7 kg axial traction with a 3-Tesla imager and CT. Three-dimensional-MRI models of the humerus and articular cartilage and a 3D-CT model of the humerus were constructed. We created MCFIs using both models. We validated the findings obtained from the MCFIs and intraoperative findings using the following items: articular cartilage fissures and defects, articular surface deformities, vertical and horizontal lesion diameters, the International Cartilage Repair Society (ICRS) classification, and surgical procedures. The MCFIs accurately reproduced the lesions and correctly matched the ICRS classification in 93.5% of cases. Surgery was performed as simulated in all cases. Preoperatively measured lesion diameters exhibited no significant differences compared to the intraoperative measurements. MCFIs were useful in the evaluation of OCD lesions and detailed preoperative surgical simulation through accurate reproduction of 3D structural details of the lesions.

18.
Neurosci Res ; 156: 237-244, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32197945

RESUMEN

It is well-known that 10-Hz alpha oscillations in humans observed by electroencephalogram (EEG) are enhanced when the eyes are closed. Toward explaining this, a previous experimental study using manipulation by transcranial magnetic stimulation (TMS) revealed more global propagation of phase resetting in the eyes-open condition than in the eyes-closed condition in the alpha band. Those results indicate a significant increase of directed information flow across brain networks from the stimulated area to the rest of the brain when the eyes are open, suggesting that sensitivity to environmental changes and external stimuli is adaptively controlled by changing the dynamics of the alpha rhythm. However, the mathematical mechanism mediating the changes in the sensitivity has not been well elucidated. In this study, we propose a qualitative mathematical model that describes the characteristic behavior of the EEG phase dynamics. Numerically, we find that the propagation properties of the phase resetting qualitatively depend on whether the population of oscillators at the stimulated area are synchronized. These results support the hypothesis that the dynamics of the alpha oscillations controls sensitivity to external stimuli.


Asunto(s)
Ritmo alfa , Electroencefalografía , Encéfalo , Humanos , Estimulación Magnética Transcraneal
19.
Phys Rev E Stat Nonlin Soft Matter Phys ; 79(4 Pt 2): 046205, 2009 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19518310

RESUMEN

Heterogeneity is one of the most important and ubiquitous types of external perturbations in dissipative systems. To know the behaviors of pulse waves in such media is closely related to studying the collision process between the pulse and the heterogeneity-induced-ordered pattern. In particular, we focus on unidirectional propagation of pulses in a medium with an asymmetric bump heterogeneity. This topic has attracted much interest recently with respect to potential computational aspects of chemical pulse propagation as well as with respect to pulse propagation in biological signal processing. We employ a three-component reaction-diffusion system with one activator and two inhibitor species to illustrate these issues. The reduced dynamics near a drift bifurcation describes the phenomena in the full partial differential equations by ordinary differential equations. Such a reduced dynamics is able to capture unidirectional propagation properties of pulses near an asymmetric heterogeneity in a qualitatively correct way. A remarkable feature is that such unidirectional behavior is linked to the imperfection of global bifurcation structure and the resulting asymmetric locations of critical points.

20.
Phys Rev E ; 99(3-1): 032207, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30999455

RESUMEN

The large-scale synchronization of neural oscillations is crucial in the functional integration of brain modules, but the combination of modules changes depending on the task. A mathematical description of this flexibility is a key to elucidating the mechanism of such spontaneous neural activity. We present a model that finds the loop structure of a network whose nodes are connected by unidirectional links. Using this model, we propose a path-finding system that spontaneously finds a path connecting two specified nodes. The solution path is represented by phase-synchronized oscillatory solutions. The model has the self-recovery property: that is, it is a system with the ability to find a new path when one of the connections in the existing path is suddenly removed. We show that the model construction procedure is applicable to a wide class of nonlinear systems arising in chemical reactions and neural networks.

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