The Dynamic Analysis of a Human Skeleton Using the Flexile Multibody Simulation Approach

The human motion study, which relies on mathematical and computational models ingeneral, and multibody dynamic biomechanical models in particular, has become asubject of many recent researches. The human body model can be applied to different physical exercises and many important results such as muscle forces, which are difficult to be measured through practical experiments, can be obtained easily. In the work, human skeletal lower limb model consisting of three bodies in build using the flexible multibody dynamics simulation approach. The floating frame of reference formulation is used to account for the flexibility in the bones of the human lower limb model. The main reason of considering the flexibility inthe human bones is to measure the strains in the bone result from different physical exercises. It has been perceived the bone under strain will become stronger in order to cope with the exercise. On the other hand, the bone strength is considered and important factors in reducing the bone fractures. The simulation approach and model developed in this work are used to measure the bone strain results from applying raising the sole of the foot exercise. The simulation results are compared to the results available in literature. The comparison shows goof agreement. This study sheds the light on the importance of using the flexible multibody dynamic simulation approach to build human biomechanical models, which can be used in developing some exercises to achieve the optimalbone strength.

Pharmacology of valsartan, an angiotensin II receptor antagonist.

Valsartan is the second orally-active, non-peptide angiotensin II receptor blocker to reach the market in Europe and the USA for the treatment of hypertension. Preclinical studies have demonstrated that this blocker is specific for the AT(1) receptor and has no affinity for the angiotensin II AT(2) receptor. Experimentally, valsartan dose-dependently inhibits the vasoconstriction induced by angiotensin II and lowers blood pressure in renin-dependent models of hypertension. Pharmacologically, oral valsartan is characterised by a low bioavailability but a rapid absorption and distribution with a half-life in keeping with once-daily administration. Thus, after oral administration, the maximal plasma concentration is reached 2 h after dosing and the elimination half-life is about 6 h. Clinically, several dose-finding and comparative studies have demonstrated that valsartan is an effective and well-tolerated antihypertensive drug in patients with mild to moderate hypertension. Valsartan has also been shown to be effective in severe hypertension. Valsartan is at least as effective as ACE inhibitors, diuretics, beta-blockers and calcium antagonists. However, none of the side-effects observed with these latter agents, including cough and lower limb oedema, has been observed with the administration of valsartan. Three large clinical trials are now underway to demonstrate whether valsartan can reduce morbidity and mortality: one in hypertensives with a high cardiovascular risk profile (VALUE), one in patients with heart failure previously treated with an angiotensin-converting enzyme inhibitor (VAL-HeFT) and one in post-myocardial infarct patients (VALIANT). These studies will further define the place of valsartan beyond the treatment of hypertension.

Malignancy transformation of chronic osteomyelitis: description of 6 cases of Marjolin's ulcers

Marjolin's ulcer describes any malignant transformation of a chronic inflammatory lesion. In the majority of cases, a squamous cell carcinoma is diagnosed. Malignant transformation occurs usually after a long period of latency of chronic infection; it takes approximately 35 years on average. There are no typical clinical presentations, but several indirect signs may suggest the malignant transformation, such as increased or changed discharge, pathologic fracture, a slow-growing exophytic mass, or other suggestive signs of malignant transformation, which should prompt to biopsy for histological exam. The diagnosis of chronic osteomyelitis should not prevent to search for carcinoma. We present six patients with chronic osteomyelitis that developed well-differentiated squamous cell carcinoma. All patients were older than 50 years (mean 60 years, range 52-77 years). Five Marjolin's ulcers were located on the lower limb and one on the arm. The average time of the chronic discharging osteomyelitis before diagnosis of carcinoma ranged between 12 and 40 years. All patients were treated by amputation of the affected limb. None had metastasis, and one patient developed local recurrence and received palliative treatment. Our study emphasizes that Marjolin's ulcer should be considered as a rare but significant long-term complication of chronic osteomyelitis. The finding of microorganisms should not prevent from further diagnostic procedures by histopathological examination so that the correct surgical treatment can be performed.

Relació entre la lateralitat i els aprenentatges escolars

Hi ha molts autors que relacionen els problemes d’aprenentatge d’un nen amb la seva lateralitat, i que atribueixen a la lateralitat contrariada, creuada o no definida els problemes en l’adquisició, entre altres, d’habilitats lectoescriptores. En aquest treball hem passat un test de lateralitat a 170 nens d’entre 6 i 7 anys (primer i segon de primària) amb proves de membre superior, membre inferior i ull, igual com de discriminació de dreta-esquerra i d’orientació espacial. Alhora, els professors tutors han valorat diversos ítems de l’aprenentatge escolar dels nens, amb qüestions sobre la seva comprensió lectora, el seu raonament matemàtic i la seva atenció a classe, entre d’altres. Segons els nostres resultats, els nens amb lateralitat homogènia destra són els que obtenen millors valoracions a tots els ítems d’aprenentatge respecte als homogenis esquerrans, els creuats i els no confirmats; els pocs casos que tenim d’homogenis esquerrans (un 3 % de la mostra) són els que tenen pitjors valoracions. A més a més, els nens que discriminen entre dreta i esquerra també tenen millors aprenentatges que no pas els que no ho fan; també s’orienten bé en l’espai en relació als que s’orienten malament.

Relación entre la lateralidad y los aprendizajes escolares

Muchos son los autores que relacionan los problemas de aprendizaje de un niño con su lateralidad, achacando a la lateralidad contrariada, cruzada o no definida los problemas en la adquisición, entre otras, de habilidades lecto-escritoras. En el presente trabajo hemos pasado un test de lateralidad a 170 niños de entre 6 y 7 años (primero y segundo de primaria) con pruebas de miembro superior, miembro inferior y ojo, así como de discriminación de derecha-izquierda y de orientación espacial. A su vez, los profesores tutores han valorado varios ítems del aprendizaje escolar de los niños, con cuestiones sobre su comprensión lectora, su razonamiento matemático y su atención en clase, entre otras. Según nuestros resultados, los niños con lateralidad homogénea diestra son los que obtienen mejores valoraciones en todos los ítems de aprendizaje con respecto a los homogéneos zurdos, los cruzados y los no confirmados, siendo los pocos casos que tenemos de homogéneos zurdos (un 3% de la muestra) los que tienen peores valoraciones. Además, los niños que discriminan entre derecha e izquierda también tienen mejor sus aprendizajes con respecto a los que no lo hacen, así como los que se orientan bien en el espacio con respecto a los que se orientan mal.

Traitement percutané de la thrombose veineuse profonde aiguë [Catheter-based treatment for acute deep vein thrombosis].

Plus de la moitié des patients présentant une thrombose veineuse profonde des membres inférieurs développent un syndrome post-thrombotique. Le risque est particulièrement élevé en cas de thrombose de l'axe principal de drainage veineux comprenant la veine fémorale commune et les veines iliaques. Plusieurs études ont démontré que l'incidence du syndrome post-thrombotique peut être diminuée si une recanalisation des veines ilio-fémorales est obtenue dans la phase aiguë. A l'heure actuelle, des techniques de recanalisation percutanées sont proposées à des patients sélectionnés présentant une thrombose ilio-fémorale. Cet article a pour but de résumer les connaissances actuelles sur la recanalisation percutanée de la thrombose veineuse profonde aiguë. Nearly half of patients with acute lower limb deep vein thrombosis (DVT) develop a post-thrombotic syndrome (PTS). This risk is particularly high in case of proximal DVT of the common femoral and iliac vein, the major lower limbs venous outflow vessel. Several studies have demonstrated that PTS incidence can be reduced with early vein recanalisation. Currently, catheter-based recanalisation therapies can be offered to selected patients with acute ilio-femoral deep vein thrombosis. Aim of the present article is to summarize current knowledge on these catheter-based recanalisation therapies.

High doses of onabotulinumtoxinA in post-stroke spasticity: a retrospective analysis.

We retrospectively evaluated the efficacy and safety of high doses of onabotulinumtoxinA (from 600 to 800 units) in 26 patients affected by upper and/or lower limb post-stroke spasticity. They were assessed before, 30 and 90 days after treatment. We observed a significant muscle tone reduction and a significant functional improvement (assessed with the Disability Assessment Scale). No adverse events were reported. In our retrospective analysis the treatment with high doses of onabotulinumtoxinA showed to be effective and safe.

Early versus delayed application of Thomas splints in patients with isolated femur shaft fractures: The benefits quantified.

AIMS: To investigate and quantify the clinical benefits of early versus delayed application of Thomas splints in patients with isolated femur shaft fractures. MATERIALS AND METHODS: Level IV retrospective clinical and radiological analysis of patients presenting from January to December 2012 at a Level 1 Trauma Unit. All skeletally mature patients with isolated femur shaft fractures independently of their mechanism of injury were included. Exclusion criteria were: ipsilateral fracture of the lower limb, neck and supracondylar femur fractures, periprosthetic and incomplete fractures. Their clinical records were analysed for blood transfusion requirements, pulmonary complications, surgery time, duration of hospital stay and analgesic requirements. RESULTS: A total of 106 patients met our inclusion criteria. There were 74 males and 32 females. Fifty seven (54%) patients were in the 'early splinted' group and 49 patients (46%) were in the 'delayed splinted' group (P>0.05). The need for blood transfusion was significantly reduced in the 'early splinted' group (P=0.04). There was a significantly higher rate of pulmonary complications in the 'delayed splinted' group (P=0.008). All other parameters were similar between the two groups. CONCLUSION: The early application of Thomas splints for isolated femur fractures in non-polytraumatised patients has a clinically and statistically significant benefit of reducing the need for blood transfusions and the incidence of pulmonary complications.

Mieux comprendre le syndrome douloureux fémoro-patellaire... pour mieux le traiter [Patellofemoral pain syndrome: understand better in order to treat better].

Le syndrome douloureux fémoro-patellaire (SDFP) est l'une des causes les plus fréquentes de douleur antérieure du genou chez l'adolescent et l'adulte. De par son étiologie complexe, multifactorielle et encore mal comprise, sa prise en charge est un important challenge pour le praticien. Le diagnostic se fait principalement sur l'anamnèse et l'examen clinique du genou mais aussi de l'ensemble du membre inférieur, pouvant parfois nécessiter la réalisation d'une imagerie. Le traitement est dans la grande majorité des cas conservateur, principalement axé sur la rééducation avec de la physiothérapie ciblée et personnalisée. Le traitement chirurgical est réservé aux cas présentant une anomalie structurelle causale. Patellofemoral pain syndrome (PFPS) is one of the most frequent cause of anterior knee pain in adolescents and adults. Due to its complex etiology, which is multifactorial and still poorly understood, its management is a major challenge for the practitioner. The diagnosis is made primarily on the history and clinical examination of the knee, but also of the entire lower limb, which may sometimes require the completion of imaging. The treatment is mostly conservative, focussing on rehabilitation with targeted and personalized therapy. Surgical treatment is reserved for cases with a causal structural lesion.

A prognostic score to identify low-risk outpatients with acute deep vein thrombosis in the upper extremity.

BACKGROUND: No studies have identified which patients with upper-extremity deep vein thrombosis (DVT) are at low risk for adverse events within the first week of therapy. METHODS: We used data from Registro Informatizado de la Enfermedad TromboEmbólica to explore in patients with upper-extremity DVT a prognostic score that correctly identified patients with lower limb DVT at low risk for pulmonary embolism, major bleeding, or death within the first week. RESULTS: As of December 2014, 1135 outpatients with upper-extremity DVT were recruited. Of these, 515 (45%) were treated at home. During the first week, three patients (0.26%) experienced pulmonary embolism, two (0.18%) had major bleeding, and four (0.35%) died. We assigned 1 point to patients with chronic heart failure, creatinine clearance levels 30-60 mL min(-1) , recent bleeding, abnormal platelet count, recent immobility, or cancer without metastases; 2 points to those with metastatic cancer; and 3 points to those with creatinine clearance levels < 30 mL min(-1) . Overall, 759 (67%) patients scored ≤ 1 point and were considered to be at low risk. The rate of the composite outcome within the first week was 0.26% (95% confidence interval [CI] 0.004-0.87) in patients at low risk and 1.86% (95% CI 0.81-3.68) in the remaining patients. C-statistics was 0.73 (95% CI 0.57-0.88). Net reclassification improvement was 22%, and integrated discrimination improvement was 0.0055. CONCLUSIONS: Using six easily available variables, we identified outpatients with upper-extremity DVT at low risk for adverse events within the first week. These data may help to safely treat more patients at home.

A multibody dynamic model of the cross-country ski-skating technique

The objective of this thesis is the development of a multibody dynamic model matching the observed movements of the lower limb of a skier performing the skating technique in cross-country style. During the construction of this model, the formulation of the equation of motion was made using the Euler - Lagrange approach with multipliers applied to a multibody system in three dimensions. The description of the lower limb of the skate skier and the ski was completed by employing three bodies, one representing the ski, and two representing the natural movements of the leg of the skier. The resultant system has 13 joint constraints due to the interconnection of the bodies, and four prescribed kinematic constraints to account for the movements of the leg, leaving the amount of degrees of freedom equal to one. The push-off force exerted by the skate skier was taken directly from measurements made on-site in the ski tunnel at the Vuokatti facilities (Finland) and was input into the model as a continuous function. Then, the resultant velocities and movement of the ski, center of mass of the skier, and variation of the skating angle were studied to understand the response of the model to the variation of important parameters of the skate technique. This allowed a comparison of the model results with the real movement of the skier. Further developments can be made to this model to better approximate the results to the real movement of the leg. One can achieve this by changing the constraints to include the behavior of the real leg joints and muscle actuation. As mentioned in the introduction of this thesis, a multibody dynamic model can be used to provide relevant information to ski designers and to obtain optimized results of the given variables, which athletes can use to improve their performance.

Lymph node transfer in the treatment of postmastectomy lymphedema

Background: Lymphedema is a debilitating disorder with few treatment options. Clinical studies have shown that microvascular lymph node transfer may improve the lymphatic function of the affected limb. This study provides information about the clinical efficacy and safety of this procedure. Further, the biological background of this technique is clarified with an analysis of postoperative production of lymphatic growth factors and cytokines related to lymphangiogenesis. Patients and Methods: The effect of lymph node transfer to recipient and donor sites was analyzed with lymphoscintigraphy, limb circumference measurements, and appearance of clinical symptoms. Axillary seroma samples were analyzed from four patient groups: Axillary lymph node removal (ALND), Microvascular breast reconstruction (BR), lymph node transfer (LN) and combined lymph node transfer and breast reconstruction (LN-BR). Results: The postoperative lymphatic transport index was improved in 7/19 patients. Ten patients were able to reduce or discontinue compression therapy 6 - 24 months postoperatively. The donor lower limb lymphatic flow was slightly impaired (Ti >10) in 2 patients. No donor site lymphedema symptoms appeared during the 8 – 56-month follow-up. A high concentration of the VEGF-C protein was detected in the seroma fluid of all flap transfer groups. The concentration of the anti-inflammatory and anti-fibrotic cytokine IL-10 was increased in the LN-BR group samples when compared to the ALND or BR group. Conclusions: According to this preliminary study, the lymph node transfer seems to be beneficial for the lymphedema patients. However, a randomized study comparing the effect of BR and LN-BR is needed to evaluate the clinical efficacy of lymph node transfer. In addition, the effect of this surgery on the donor site needs to be studied further. The clinical effects of the lymph node transfer might be partly mediated by increased production of the lymphangiogenic growth factor (VEGF-C) as well as the anti-fibrotic cytokine (IL-10).

Does Bracing affect Bone Health in Females with adolescent Idiopathic Scoliosis?

This study examined the bone mineral content (BMC) in young women with Adolescent Idiopathic Scoliosis (AIS), treated with a brace (27.9 ±21.6 months, for 18.0±5.4 h/d) during adolescence (AIS-B, n = 15, 25.6 ±5.8 yrs), versus women with AIS but no treatment (AIS-NB, n = 15, 24.0 ±4.0 yrs), and women without AIS (C, n = 19, 23.5 ±3.8 yrs). After controlling for lean body mass, calcium and vitamin D daily intake, and strenuous physical activity, femoral neck BMC was lower in the AIS-B compared with AIS-NB and C (all p’s < .05). In summary, women with AIS, braced during their growing years are characterized by low lower limb BMC. However, the lack of a relationship between brace treatment duration and BMC, suggests that bracing was not the likely mechanism.

The effect of perturbation warning on attention switching abilities during dual-task performance in young and older adults

This study examined whether providing an auditory warning would facilitate attention switching abilities in older adults during dual-tasking. Fifteen young and 16 older adults performed a tracking task while recovering their balance from a support surface translation. For half of the trials, an auditory warning was presented to inform participants of the upcoming translation. Performance was quantified through electromyographic (EMG) recordings of the lower limb muscles, while the ability to switch attention between tasks was determined by tracking task error. Providing warning of an upcoming loss of balance resulted in both young and older adults increasing their leg EMG activity by 10-165% (p<0.05) in preparation for the upcoming translation. However, no differences in the timing of attention switching were observed with or without the warning (p=0.424). Together, these findings suggest that providing a perturbation warning has minimal benefits in improving attention switching abilities for balance recovery in healthy older adults.

Can Attention Focus Instructions Reduce the Effects of Fatigue on Balance Control?

Localized muscular fatigue has been identified to have detrimental effects on balance control, an important skill for everyday life. Manipulation of attention focus instructions has been shown to benefit performance of various motor skills including balance and has been found to facilitate endurance during fatiguing tasks. The purpose of this thesis was to determine if the use of attention focus instructions could attenuate the effects of muscular fatigue on balance control. Twenty-four participants performed a balance task (two-legged stance on an unstable platform) before and after a fatigue protocol. Trunk sway, platform excursions, and lower limb muscle activity was measured. Results suggest that use of either internal or external attention focus instructions can reduce the immediate effects of muscular fatigue of the lower limb on balance control as shown through reduced trunk sway and platform excursions. These results have relevance for individuals performing balance tasks in a fatigued state.