The Efficacy of Simultaneously Training 2 Motion Targets During a Squat Using Auditory Feedback.

Auditory feedback is a simple, low-cost training solution that can be used in rehabilitation, motor learning, and performance development. The use has been limited to the instruction of a single kinematic or kinetic target. The goal of this study was to determine if auditory feedback could be used to simultaneously train 2 lower-extremity parameters to perform a bodyweight back squat. A total of 42 healthy, young, recreationally active males participated in a 4-week training program to improve squat biomechanics. The Trained group (n = 22) received 4 weeks of auditory feedback. Feedback focused on knee flexion angle and center of pressure under the foot at maximum squat depth. The Control group (n = 20) performed squats without feedback. Subjects were tested pre, post, and 1 week after training. The Trained group achieved average target knee flexion angle within 1.73 (1.31) deg (P < .001) after training and 5.36 (3.29) deg (P < .01) at retention. While achieving target knee flexion angle, the Trained group maintained target center of pressure (P < .001). The Control group improved knee range of motion, but were not able to achieve both parameter targets at maximum squat depth (P < .90). Results from this study demonstrate that auditory feedback is an effective way to train 2 independent biomechanical targets simultaneously.

Quantified in vitro tibiofemoral contact during bodyweight back squats.

Squats are a common lower extremity task used in strength and conditioning, balance training, and rehabilitation. It is important to understand how slight alterations in lower extremity kinematics during a squat affect the internal joint loading of the knee. This study directly quantified tibiofemoral contact throughout the in vitro simulation of a bodyweight back squat performed two ways: a heel squat (knees in line with toes) and a toe squat (knees anterior to the toes) at peak knee flexion. Three cadaveric right lower extremities were instrumented and positioned into the University of Texas Joint Load Simulator. Kinematics, kinetics, and predicted muscle forces from a 20-year-old athletic male performing the two back squats were used as inputs for the in vitro simulations. The quantified tibiofemoral contact area, peak pressure, net force, and center of pressure location were significantly different between squat types (p > 0.05). Net contact area on the tibial plateau at peak knee flexion was significantly larger in the heel versus toe squat (599 ±â€¯80 mm2 vs. 469 ±â€¯125 mm2; p < 0.05). Peak lateral pressure was significantly higher in the heel versus toe squat (2.73 ±â€¯0.54 MPa vs. 0.87 ±â€¯0.56 MPa; p < 0.05). Results suggest the heel squat generates an even load distribution, which is less likely to affect joint degeneration. Future in vitro simulations should quantify the effects lower extremity kinematics, kinetics, and individual muscle forces have on tibiofemoral contact parameters during common athletic tasks.

A Reconfigurable Multiplanar In Vitro Simulator for Real-Time Absolute Motion With External and Musculotendon Forces.

Advancements in computational musculoskeletal biomechanics are constrained by a lack of experimental measurement under real-time physiological loading conditions. This paper presents the design, configuration, capabilities, accuracy, and repeatability of The University of Texas at El Paso Joint Load Simulator (UTJLS) by testing four cadaver knee specimens with 47 real-time tests including heel and toe squat maneuvers with and without musculotendon forces. The UTJLS is a musculoskeletal simulator consisting of two robotic manipulators and eight musculotendon actuators. Sensors include eight tension load cells, two force/torque systems, nine absolute encoders, and eight incremental encoders. A custom control system determines command output for position, force, and hybrid control and collects data at 2000 Hz. Controller configuration performed forward-dynamic control for all knee degrees-of-freedom (DOFs) except knee flexion. Actuator placement and specimen potting techniques uniquely replicate muscle paths. Accuracy and repeatability standard deviations across specimen during squat simulations were equal or less than 8 N and 5 N for musculotendon actuators, 30 N and 13 N for ground reaction forces (GRFs), and 4.4 N·m and 1.9 N·m for ground reaction moments. The UTJLS is the first of its design type. Controller flexibility and physical design support axis constraints to match traditional testing rigs, absolute motion, and synchronous real-time simulation of multiplanar kinematics, GRFs, and musculotendon forces. System DOFs, range of motion, and speed support future testing of faster maneuvers, various joints, and kinetic chains of two connected joints.

Characterization of individuals at high risk of developing melanoma in Latin America: bases for genetic counseling in melanoma.

PURPOSE: CDKN2A is the main high-risk melanoma-susceptibility gene, but it has been poorly assessed in Latin America. We sought to analyze CDKN2A and MC1R in patients from Latin America with familial and sporadic multiple primary melanoma (SMP) and compare the data with those for patients from Spain to establish bases for melanoma genetic counseling in Latin America. METHODS: CDKN2A and MC1R were sequenced in 186 Latin American patients from Argentina, Brazil, Chile, Mexico, and Uruguay, and in 904 Spanish patients. Clinical and phenotypic data were obtained. RESULTS: Overall, 24 and 14% of melanoma-prone families in Latin America and Spain, respectively, had mutations in CDKN2A. Latin American families had CDKN2A mutations more frequently (P = 0.014) than Spanish ones. Of patients with SMP, 10% of those from Latin America and 8.5% of those from Spain had mutations in CDKN2A (P = 0.623). The most recurrent CDKN2A mutations were c.-34G>T and p.G101W. Latin American patients had fairer hair (P = 0.016) and skin (P < 0.001) and a higher prevalence of MC1R variants (P = 0.003) compared with Spanish patients. CONCLUSION: The inclusion criteria for genetic counseling of melanoma in Latin America may be the same criteria used in Spain, as suggested in areas with low to medium incidence, SMP with at least two melanomas, or families with at least two cases among first- or second-degree relatives.Genet Med 18 7, 727-736.

Dermatoscopic pattern of digital mucous cyst: report of three cases.

Digital mucous cysts are benign ganglion cysts of the digits typically located on the dorsal aspect of the interphalangeal joint and distal phalanx of the digits. Usually the clinical diagnosis is straightforward, though sometimes it may mimic other lesions and diagnosis becomes a challenge. We present a series of three digital mucous cysts with a repeatable dermoscopic pattern consisted of linear branched and serpentine vessels when no compression is applied and translucent aspect with white bright areas and loss of vascular pattern when compression is applied.

A preliminary study on the differences in male and female muscle force distribution patterns during squatting and lunging maneuvers.

In the United States, 250,000 people tear their anterior cruciate ligament (ACL) annually with females at higher risk of ACL failure than males. By predicting muscle forces during low impact maneuvers we may be able to estimate possible muscle imbalances that could lead to ACL failure during highly dynamic maneuvers. The purpose of this initial study was to predict muscle forces in males and females similar in size and activity level, during squat and lunge maneuvers. We hypothesized that during basic low impact maneuvers (a) distribution of quadriceps forces are different in males and females and (b) females exhibit quadriceps dominance when compared to males. Two males and three females performed squatting and lunging maneuvers while electromyography (EMG) data, motion capture data, and ground reaction forces were collected. Nine individual muscle forces for muscles that cross the knee were estimated using an EMG-driven model. Results suggest that males activate their rectus femoris muscle more than females, who in turn activate their vastus lateralis muscle at their maximum flexion angle, and more their vastus medialis muscle when ascending from a squat. During the lunge maneuver, males used greater biceps femoris force than females, throughout the lunge, and females exhibited higher semitendinosus force. Quadriceps dominance was evident in both males and females during the prescribed tasks, and there was no statistical difference between genders. Understanding individual muscle force distributions in males and females during low impact maneuvers may provide insights regarding failure mechanisms during highly dynamic maneuvers, when ACL injuries are more prevalent.

Recurrent melanocytic nevi and melanomas in dermoscopy: results of a multicenter study of the International Dermoscopy Society.

IMPORTANCE Differentiating recurrent nevi from recurrent melanoma is challenging. OBJECTIVE To determine dermoscopic features to differentiate recurrent nevi from melanomas. DESIGN, SETTING, AND PARTICIPANTS Retrospective observational study of 15 pigmented lesion clinics from 12 countries; 98 recurrent nevi (61.3%) and 62 recurrent melanomas (38.8%) were collected from January to December 2011. MAIN OUTCOMES AND MEASURES Scoring the dermoscopic features, patterns, and colors in correlation with the histopathologic findings. RESULTS In univariate analysis, radial lines, symmetry, and centrifugal growth pattern were significantly more common dermoscopically in recurrent nevi; in contrast, circles, especially if on the head and neck area, eccentric hyperpigmentation at the periphery, a chaotic and noncontinuous growth pattern, and pigmentation beyond the scar's edge were significantly more common in recurrent melanomas. Patients with recurrent melanomas were significantly older than patients with recurrent nevi (mean [SD] age, 63.1 [17.5] years vs 30.2 [12.4] years) (P<.001), and there was a significantly longer time interval between the first procedure and the second treatment (median time interval, 25 vs 8 months) (P<.001). In a multivariate analysis, pigmentation beyond the scar's edge (P=.002), age (P<.001), and anatomic site (P=.002) were significantly and independently associated with the diagnosis of recurrent melanoma in dermoscopy. CONCLUSIONS AND RELEVANCE Dermoscopically, pigmentation beyond the scar's edge is the strongest clue for melanoma. Dermoscopy is helpful in evaluating recurrent lesions, but final interpretation requires taking into account the patient age, anatomic site, time to recurrence, growth pattern, and, if available, the histopathologic findings of the first excision.

Individual muscle force parameters and fiber operating ranges for elbow flexion-extension and forearm pronation-supination.

We have quantified individual muscle force and moment contributions to net joint moments and estimated the operating ranges of the individual muscle fibers over the full range of motion for elbow flexion/extension and forearm pronation/supination. A three dimensional computer graphics model was developed in order to estimate individual muscle contributions in each degree of freedom over the full range of motion generated by 17 muscles crossing the elbow and forearm. Optimal fiber length, tendon slack length, and muscle specific tension values were adjusted within the literature range from cadaver studies such that the net isometric joint moments of the model approximated experimental joint moments within one standard deviation. Analysis of the model revealed that the muscles operate on varying portions of the ascending limb, plateau region, and descending limb of the force-length curve. This model can be used to further understand isometric force and moment contributions of individual muscles to net joint moments of the arm and forearm and can serve as a comprehensive reference for the forces and moments generated by 17 major muscles crossing the elbow and wrist.

In vitro antimicrobial susceptibility of Propionibacterium acnes isolated from acne patients in northern Mexico.

BACKGROUND: Antimicrobials are essential in acne therapy. In the last decades, Propionibacterium acnes has become resistant to different antibiotics. OBJECTIVE: To determine antimicrobial susceptibility patterns of P. acnes to frequently used drugs. MATERIALS AND METHODS: Cutaneous lesion samples were obtained from 50 patients with acne vulgaris, which were cultured in anaerobic media to demonstrate the presence of P. acnes. After that, antimicrobial susceptibility tests to tetracycline, minocycline, doxycycline, erythromycin, azithromycin, clindamycin, trimethoprim/sulfamethoxazole (SXT) and levofloxacin were performed. RESULTS: In the general study group, resistance to azithromycin was 82%, the most prevalent one (P < 0.05), followed by trimethoprim/sulfamethoxazole (68%) and erythromycin (46%). On the other hand, all strains isolated were susceptible to minocycline. Resistance bias were similar when subgroups with and without the previous antimicrobial therapy were performed, finding a low prevalence of resistance to tetracyclines and levofloxacin in both groups. CONCLUSIONS: In our region, P. acnes is highly resistant to azithromycin, SXT, erythromycin and clindamycin; and being very susceptible to minocycline, levofloxacin and tetracycline, in vitro in both groups: with and without the previous antibiotic use. To our knowledge, high resistance prevalence to azithromycin and SXT has never been reported.

Muscle moment arm and normalized moment contributions as reference data for musculoskeletal elbow and wrist joint models.

A geometric musculoskeletal model of the elbow and wrist joints was developed to calculate muscle moment arms throughout elbow flexion/extension, forearm pronation/supination, wrist flexion/extension and radial/ulnar deviation. Model moment arms were verified with data from cadaver specimen studies and geometric models available in the literature. Coefficients of polynomial equations were calculated for all moment arms as functions of joint angle, with special consideration to coupled muscles as a function of two joint angles. Additionally, a "normalized potential moment (NPM)" contribution index for each muscle across the elbow and wrist joints in four degrees-of-freedom was determined using each muscle's normalized physiological cross-sectional area (PCSA) and peak moment arm (MA). We hypothesize that (a) a geometric model of the elbow and wrist joints can represent the major attributes of MA versus joint angle from many literature sources of cadaver and model data and (b) an index can represent each muscle's normalized moment contribution to each degree-of-freedom at the elbow and wrist. We believe these data serve as a simple, yet comprehensive, reference for how the primary 16 muscles across the elbow and wrist contribute to joint moment and overall joint performance.

Real-time haptic-teleoperated robotic system for motor control analysis.

A versatile teleoperated robotic system was created as an assessment device for testing upper-extremity motor control adaptation using different control strategies. While many systems display output virtually on a computer monitor, this system was designed to output in three-dimensional physical space. The system accepts haptic force and torque input, and outputs robot end-effector displacements and rotations in three spatial dimensions. Benefits of this system include flexibility to conduct a variety of dissimilar tasks and reality of user feedback in physical space. Two separate experiments validated the teleoperated robotic system. The first experiment tested unimanual human motor control and the second tested bimanual motor control. This teleoperated robotic system can be used as an assessment device to study neuromuscular adaptability via a variety of control strategies providing a new and functional approach to human motor control analysis.

Genetically-designed neural networks for error reduction in an optimized biomechanical model of the human elbow joint complex.

A real time dynamic biomechanical model of the human elbow joint has been used as the first step in the process of calculating time varying joint position from the electromyograms (EMGs) of eight muscles crossing the joint. Since calculation of position has a high sensitivity to errors in the model torque calculation, a genetic algorithm (GA) neural network (NN) has been developed for automatic error reduction in the dynamic model. Genetic algorithms are used to design many neural network structures during a preliminary trial effort, and then each network's performance is ranked to choose a trained network that represents the most accurate result. Experimental results from three subjects have shown model error reduction in 84.2% of the data sets from a subject on which the model had been trained, and 52.6% of the data sets from the subjects on which the model had not been trained. Furthermore, the GA networks reduced the error standard deviation across all subjects, showing that progress in error reduction was made evenly across all data sets.

A real-time EMG-driven virtual arm.

An EMG-driven virtual arm is being developed in our laboratories for the purposes of studying neuromuscular control of arm movements. The virtual arm incorporates the major muscles spanning the elbow joint and is used to estimate tension developed by individual muscles based on recorded electromyograms (EMGs). It is able to estimate joint moments and the corresponding virtual movements, which are displayed in real-time on a computer screen. In addition, the virtual arm offers artificial control over a variety of physiological and environmental conditions. The virtual arm can be used to examine how the neuromuscular system compensates for the partial or total loss of a muscle's ability to generate force as might result from trauma or pathology. The purpose of this paper is to describe the design objectives, fundamental components and implementation of our real-time, EMG-driven virtual arm.

Comportamiento de la morbilidad y la mortalidad en pacientes con pie diabetico / Behavior of morbidity and mortality in patients with diabetic foot

Se realizó un estudio retrospectivo sobre el comportamiento de la morbilidad y la mortalidad de los pacientes con pie diabético en el servicio de Angiología y Cirugía Vascular del Hospital General Docente "Agostinho Neto", de Guantánamo, en el período comprendido entre enero de 1996 y diciembre de 1997. Se encontró un predominio de esta enfermedad en el sexo femenino con más de 50 años de edad entre los pacientes diabéticos tipo II, después de 10 años de evolución de la diabetes mellitus y los cuales llevaban un mal control metabólico. Apareció un mayor número de casos del pie diabético neuroinfeccioso (80,95 porciento), de la oclusión de las arterias de la pierna y el pie (58,50 porciento); en los que las técnicas quirúrgicas más empleadas fueron las desarticulaciones de dedos y toilette, seguidas de las amputaciones mayores; hubo una elevada estadía hospitalaria y la causa más frecuente de muerte fue el tromboembolismo pulmonar(AU)

Aproximación al diagnóstico de salud Estado Mérida, Venezuela 1983-1987 / Approximation to the diagnostic of health Merida State, Venezuela 1983-1987

Los autores mediante este diagnóstico, pretenden: 1) aportar una base sólida que oriente los planes del sector de salud oficial del Estado Mérida. 2) Cuantificar a través de los indicadores apropiados, el estado de salud de esa población durante el lapso 1983-1987, incluyendo su morbilidad, mortalidad y situación nutricional. 3) Describe la situación epidemiológica del Estado, incluyendo algunos aspectos meteorológicos, demográficos, educacionales, económicos y el saneamiento ambiental

Trombosis venosa profunda aguda de las extremidades: análisis estadístico en un año / Acute deep venous thrombosis of the extremities: statistical analysis in a year

Se revisan las historias clínicas de los pacientes afectados de trombosis venosa, ingresados en un año en el Servicio de Angiología y Cirugía Vascular. Se determinan su incidencia, factores de riesgo, localización, tratamientos y complicaciones

Trombosis venosa profunda aguda de las extremidades. análisis estadístico en un año / Acute deep venous thrombosis of the extremities: statistical analysis in a year

Se revisan las historias clínicas de los pacientes afectados de trombosis venosa, ingresados en un año en el Servicio de Angiología y Cirugía Vascular. Se determinan su incidencia, factores de riesgo, localización, tratamientos y complicaciones

Síndrome post-flebítico y flebografía retrogada femoral

Se revisaron 115 expedientes clínicos de pacientes sospechosos del antecedente de trombosis venosa íleo-femoral con la posible secuela de síndrome post-flebítico o post-trombótico, divididos en dos grupos: uno con edema, 57 casos que representaron el 49,5 por ciento, y el otro con úlceras y várices, 58 que representaron el 50, 5 por ciento. Se señalan los patrones flebíticos según la clasificación del profesor Dr. Mc Cook, en dos fases: obstrucción venosa profunda y recanalización. Se demuestra lo planteado de que en la fase de recanalización del sistema venosa profundo con destrucción valvular, se establecen las várices para suplencia y la formación de trastornos tróficos con el resultado final de la úlcera post-flebítica(AU)

Enfermedad granulomatosa cronica (sindrome de deficiencia de oxidasa fagocitaria): analisis de un paciente adulto y su familia / Chronic granulomatous disease (fagocytic oxydase deficiency syndrome): analysis of an adult patient and his family

La enfermedad granulomatosa cronica es un defecto congenito de los fagocitos, que se manifiesta clinicamente con infecciones severas y recurrentes principalmente en niños. La forma clasica debe sospecharse en los niños con infecciones recurrentes y severas en piel, pulmones y otros organos y la presencia de granulomas en esos sitios. No obstante, en los ultimos años, se ha descrito este problema en adultos, con una amplia gama de patrones geneticos y variadas manifestaciones clinicas. Se señala el de "sindrome de deficiencia de oxidasa fagocitaria" como el nombre mas adecuado, puesto que incluye todos los posibles defectos bioquimicos observados en estos pacientes. En el presente articulo se analizan los hallazgos en un paciente adulto con este trastorno y su familia.