Comparación de métodos histoquímicos para el análisis histológico de muestras de encía humana / Comparison of histochemical methods for the histological analysis of human gingival samples

Introducción: Las técnicas de coloración histológica son útiles en el análisis ultraestructural de muestras tisulares, incluyendo el tejido gingival. Objetivo: Comparar la utilidad de tres métodos histoquímicos (hematoxilina-eosina, Masson Goldner y rojo sirio) en la identificación de elementos celulares y otros constituyentes del tejido gingival. Métodos: Estudio experimental in vitro que comprendió el análisis de tejidos gingivales de donantes sanos sin signos de inflamación gingival y con indicación de cirugía periodontal. Las muestras de encía se obtuvieron mediante gingivectomía, se procesaron e incluyeron en parafina, posteriormente se realizaron cortes con un micrótomo y se depositaron en portaobjetos de adhesión con polisina. Las muestras se agruparon y fueron teñidas con hematoxilina-eosina, Masson Goldner y rojo sirio, finalmente fueron visualizadas en un microscopio óptico Leica DM 750®. La lectura de los hallazgos fue realizada por patólogos orales. Resultados: La coloración hematoxilina-eosina evidencia elementos celulares y extracelulares del tejido epitelial y conectivo. Núcleos de color azul violeta, citoplasmas rosados, fibras de colágeno de matiz rosa claro, arteriolas y vénulas con túnica adventicia, media e íntima diferenciadas. La coloración Masson Goldner diferencia núcleos de coloración púrpura y citoplasma fucsia, presenta especificidad en identificar fibras de colágeno con tonalidad verde, distribuidas densa, homogénea y paralelamente en el tejido conectivo gingival. La tinción rojo sirio, permitió identificar las fibras de colágeno de color rosa brillante, mientras que el tejido epitelial y los vasos sanguíneos fueron de color amarillo. Conclusión: Cada coloración histológica evaluada en el presente trabajo tiene cierta afinidad y sensibilidad por estructuras celulares y componentes de la matriz extracelular específica. Su empleo es útil en el estudio de tejidos gingivales y podrían contribuir en el análisis de biopsias gingivales(AU)

Introduction: Histological staining techniques are useful in the ultrastructural analysis of tissue samples, including gingival tissue. Objective: Compare the usefulness of three histochemical methods (hematoxylin-eosin, Masson-Goldner and sirius red) for identification of cellular elements and other constituents of gingival tissue. Methods: An in vitro experimental study was conducted which included the analysis of gingival tissue from healthy donors without gingival inflammation signs and indication of periodontal surgery. The gum samples were obtained by gingivectomy, processed with paraffin, cut with a microtome and placed on Polysine adhesion slides. The samples were grouped, stained with hematoxylin-eosin, Masson Goldner and sirius red, and visualized under a Leica DM 750® microscope. Reading of the findings was performed by oral pathologists. Results: Hematoxylin-eosin staining found cellular and extracellular elements of the epithelial and connective tissue: violet-blue nuclei, pink cytoplasms, light rose collagen fibers, and arterioles and venules with differentiated tunica adventitia, media and intima. Masson-Goldner staining differentiated purple nuclei and fuchsia cytoplasm. It displayed specificity identifying green collagen fibers with dense, homogeneous and parallel distribution in the gingival connective tissue. Sirius red staining allowed identification of bright rose collagen fibers, whereas epithelial tissue and blood vessels were yellow. Conclusion: Each of the histological staining methods evaluated in the study shows a certain affinity with and sensitivity to cellular structures and components of the specific extracellular matrix. All three are useful for the study of gingival tissue and could contribute to the analysis of gingival biopsies(AU)

Outcomes After Arthroscopic Repair in Patients With Tears of Hypertrophic Versus Morphologically Normal Acetabular Labra.

BACKGROUND: Recently, a hypertrophic labrum has been reported in the absence of hip dysplasia, which can possibly contribute to an acetabular labral tear. PURPOSE: To compare the clinical outcomes and complications, including the incidence of iatrogenic acetabular labrum and cartilage injury, in patients with tears of hypertrophic versus morphologically normal acetabular labra over a minimum follow-up period of 2 years and to assess the morphologic changes at follow-up computed tomography arthrography in the 2 groups. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between January 2010 and December 2016, 20 patients (22 hips) with a hypertrophic labrum underwent arthroscopic hip surgery. A total of 22 patients (22 hips) without a hypertrophic labrum were assigned to the control group based on matching criteria, including age, sex, body mass index, labral tear, and labral repair. Clinical outcomes were assessed with the visual analog scale score, UCLA activity scale score (University of California, Los Angeles), and modified Harris Hip Score. Radiologic outcomes were assessed through serial radiography. Patients were followed for at least 2 years. RESULTS: The mean age at surgery was 42 years. The most common cause of arthroscopic surgery in the study group was an isolated acetabular labral tear without any bony structural abnormalities (68.2%, 15 of 22 hips). All improvements in both groups were statistically significant at the last postoperative follow-up (P < .001). Although the radiologic and clinical outcomes were not significantly different between the groups, the complication rates, including iatrogenic labral perforations and cartilage injury, were significantly higher in patients with hypertrophic acetabular labral tears (9 vs 3, P = .042). The patient-reported satisfaction scores at the last postoperative follow-up were 8.4 and 7.9 in the study and control groups, respectively (P = .351). CONCLUSION: The high rates of patient-reported satisfaction and the clinical outcomes after arthroscopic repair in both groups are encouraging. Arthroscopic treatment in patients with hypertrophic acetabular labral tears should be carefully performed to prevent iatrogenic injury during the surgery, and isolated hypertrophic labral tears can have good results after repair.

Electrocautery in arthroscopic surgery: intra-articular fluid temperatures above 43 °C cause potential tissue damage.

PURPOSE: The use of electrocautery during arthroscopy may heat intra-articular saline and subsequently damage intra- and extra-articular tissue. Newer electrocautery devices have the ability to measure the outflow fluid temperature and switch off before reaching a certain threshold; however, the scientific evidence establishing these temperature thresholds' potential for inadvertent damage is lacking. The aim of this study was to analyse current available literature on temperature thresholds for tissue damage after exposure to heated fluid and provide a recommendation for the maximum temperature of intra-articular fluid to prevent tissue damage. METHODS: In February 2018, a systematic literature review was performed using the MEDLINE/PubMed and Embase databases. Inclusion was limited to studies investigating temperature thresholds for thermal damage to at least one of the tissues of interest: skin, bone, cartilage, soft tissues, and nerves. Studies not reporting specific temperature thresholds for thermal damage were excluded. RESULTS: Twenty articles were selected for the final evaluation and data extraction. Varying temperature thresholds, based on the lowest reported temperature causing tissue damage, were found for the different tissues of interest: 44 °C for dermal tissues, between 47 and 50 °C for bony tissues, 50 °C for cartilage, between 43 and 55 °C for soft tissues, and 43 °C for nerves. CONCLUSION: Based on the current literature, a temperature threshold for intra-articular fluid of 43 °C during an arthroscopic procedure is recommended to prevent tissue damage. Higher temperatures may cause damage to surrounding intra- and extra-articular tissues. The threshold for irreversible damage is likely to be higher. In clinical practise, one should be aware of possible heating of intra-articular fluid when using electrocautery and related risk of tissue damage. LEVEL OF EVIDENCE: III.

[Decellularized cadaveric human artery for substitution of connective tissue and smooth muscle defects on the example of tunica albuginea of penis (experimental work)]. / Ispol'zovanie detselliuliarizirovannoi trupnoi arterii cheloveka dlia zameshcheniia defektov soedinitel'notkannykh i gladkomyshechnykh struktur na primere belochnoi obolochki polovogo chlena (éksperimental'naia rabota).

AIM: To analyze experimentally the outcomes of xenotransplantation (cadaveric artery, decellularized cadaveric artery) for tunica albuginea defects repair. MATERIAL AND METHODS: The study included 60 chinchilla rabbits. Rabbits underwent local replacement of tunica albuginea. Animals were divided into 2 groups (group 1 - human cadaveric artery, group 2 - decellularized cadaveric artery). The result was considered after 7, 14 and 30 days postoperatively. RESULTS: Tendency to stasis, sludge-phenomenon and ultimately development of fibrosis of transplantation area were histologically observed in group 1 after 30 days. In group 2 luminal surface of decellularized artery was smoothed, fibrin and blood elements were absent. In group 1 mean level of C-reactive protein was 3.86±0.43, 1.17±0.2 and 0.73±0.16 mg/L after 7, 14 and 30 days respectively. In group 2 the same values were 0.33±0.03, 0.23±0.03 and 0.11±0.02 mg/L. Differences were significant (t =-46.28, t = -25.95, t = -14.84; p<0.0001).

Ultrasound-detected connective tissue involvement in acute muscle injuries in elite athletes and return to play: The French National Institute of Sports (INSEP) study.

OBJECTIVES: Previous MRI studies showed that involvement of connective tissue in muscle injuries may prolong recovery times. The relevance of ultrasound assessment of connective tissue involvement as a prognostic factor is unknown. The aim was to test the hypothesis that ultrasound-detected connective tissue involvement in acute muscle injuries are related to longer recovery times. DESIGN: Cohort study. METHODS: Seventy consecutive elite athletes from the French National Institute of Sports (INSEP) sustaining an acute muscle injury showing positive findings on ultrasound at baseline were included. Ultrasound was systematically performed within 7days after the injury for the assessment of severity (grades 1-4) and type of injury in regard to the absence (M injuries) or presence (C injuries) of connective tissue involvement. The differences in the mean time needed to return to play (RTP) between the different grades and types of injury were assessed using multiple non-parametric tests. RESULTS: When considering the overall grades independently of the type of injury (M or C), an increase in the mean time needed to RTP was observed with the increase of grades (p<0.0001). The same relationship was found when considering grades from M and C injuries separately, with higher grades of injuries exhibiting longer times needed to RTP (p<0.0001). Longer times needed to RTP were observed in athletes demonstrating C injuries in comparison to the ones exhibiting M injuries overall (p=0.002). CONCLUSIONS: Ultrasound-detected connective tissue involvement in acute muscle injuries are related to longer times needed to RTP, especially when disruption is detected.

Maturation State and Matrix Microstructure Regulate Interstitial Cell Migration in Dense Connective Tissues.

Few regenerative approaches exist for the treatment of injuries to adult dense connective tissues. Compared to fetal tissues, adult connective tissues are hypocellular and show limited healing after injury. We hypothesized that robust repair can occur in fetal tissues with an immature extracellular matrix (ECM) that is conducive to cell migration, and that this process fails in adults due to the biophysical barriers imposed by the mature ECM. Using the knee meniscus as a platform, we evaluated the evolving micromechanics and microstructure of fetal and adult tissues, and interrogated the interstitial migratory capacity of adult meniscal cells through fetal and adult tissue microenvironments with or without partial enzymatic digestion. To integrate our findings, a computational model was implemented to determine how changing biophysical parameters impact cell migration through these dense networks. Our results show that the micromechanics and microstructure of the adult meniscus ECM sterically hinder cell mobility, and that modulation of these ECM attributes via an exogenous matrix-degrading enzyme permits migration through this otherwise impenetrable network. By addressing the inherent limitations to repair imposed by the mature ECM, these studies may define new clinical strategies to promote repair of damaged dense connective tissues in adults.

Validation of a new experimental model of extrusive luxation on maxillary molars of rats: a histological study.

BACKGROUND/AIM: The aim of this study was to test and validate a new model of extrusive luxation trauma on maxillary first molars of rats. MATERIAL AND METHODS: Forty adult male rats (Rattus norvegicus albinus, Wistar; weight = 230-250 g), 45 days old, were divided into eight groups (n = 5): control groups, in which animals were not subjected to any procedure and waited 1 day (GC1D) or 3 days (GC3D) for euthanasia, and experimental groups, in which animals were subjected to forces of 1100cN, 1300cN, or 1500cN and waited 1 or 3 days for euthanasia (GT1100/1D, GT1100/3D, GT1300/1D, GT1300/3D, GT1500/1D, GT1500/3D). In animals of the experimental groups, trauma was produced by an extrusive force in maxillary first right molars. Four-micrometer serial cuts stained with hematoxylin and eosin (HE) were made. Descriptive microscopic analysis of first upper right molar and semi-quantitative analysis (scores 1 to 4) of intensity of acute and chronic inflammation and vascular changes in the periodontal ligament and active and inactive external root resorption were conducted. The distribution of scores in the groups was compared using the Freeman-Halton extension of Fisher's exact test. The significance level was 5%. RESULTS: It was observed that vascular disorders (bleeding) on the periodontal ligament became more evident with increasing extrusive force. CONCLUSIONS: This new method was capable of generating histological changes, proving its secure application in this research area. The 1500cN force produced more damage on the periodontal ligament. CLINICAL RELEVANCE: The validation of a new experimental method can produce more reliable evidence in further research.

Connective tissue injury in calf muscle tears and return to play: MRI correlation.

OBJECTIVE: The aim of our study was to assess a group of patients with calf muscle tears and evaluate the integrity of the connective tissue boundaries and interfaces. Further, we propose a novel MRI grading system based on integrity of the connective tissue and assess any correlation between the grading score and time to return to play. We have also reviewed the anatomy of the calf muscles. MATERIALS AND METHODS: We retrospectively evaluated 100 consecutive patients with clinical suspicion and MRI confirmation of calf muscle injury. We evaluated each calf muscle tear with MRI for the particular muscle injured, location of injury within the muscle and integrity of the connective tissue structure at the interface. The muscle tears were graded 0-3 depending on the degree of muscle and connective tissue injury. The time to return to play for each patient and each injury was found from the injury records and respective sports doctors. RESULTS: In 100 patients, 114 injuries were detected. Connective tissue involvement was observed in 63 out of 100 patients and failure (grade 3 injury) in 18. Mean time to return to play with grade 0 injuries was 8 days, grade 1 tears was 17 days, grade 2 tears was 25 days and grade 3 tears was 48 days (p<0.001). CONCLUSION: The integrity of the connective tissue can be used to estimate and guide the time to return to play in calf muscle tears.

[The mechanical strenth characteristics of the biological tissues: the current state-of-the-art]. / Prochnostnye svoistva biologicheskikh tkanei: sovremennoe sostoianie voprosa.

This article reports the results of analysis of the publications in the scientific literature concerning the mechanical strength characteristics of the biological (human) tissues. It is shown that many researchers successfully used the methods and means finding wide applications in the technical disciplines for the investigations into the mechanical strength of such biological objects as skin, tendons, blood vessels, bones, etc. There are thus far no available reports on the studies of the mechanical strength characteristics of the internal organs. At the same time, such studies are of paramount importance for obtaining the materials that might greatly contribute to the better understanding of the mechanisms underlying the development of the lesions in the internal organs. They are likely to enhance objectiveness of expert conclusions in the framework of forensic medical expertise of the injuries to the human body.

Connective tissue regeneration in skeletal muscle after eccentric contraction-induced injury.

Human skeletal muscle has the potential to regenerate completely after injury induced under controlled experimental conditions. The events inside the myofibers as they undergo necrosis, followed closely by satellite cell-mediated myogenesis, have been mapped in detail. Much less is known about the adaptation throughout this process of both the connective tissue structures surrounding the myofibers and the fibroblasts, the cells responsible for synthesizing this connective tissue. However, the few studies investigating muscle connective tissue remodeling demonstrate a strong response that appears to be sustained for a long time after the major myofiber responses have subsided. While the use of electrical stimulation to induce eccentric contractions vs. voluntary eccentric contractions appears to lead to a greater extent of myofiber necrosis and regenerative response, this difference is not apparent when the muscle connective tissue responses are compared, although further work is required to confirm this. Pharmacological agents (growth hormone and angiotensin II type I receptor blockers) are considered in the context of accelerating the muscle connective tissue adaptation to loading. Cautioning against this, however, is the association between muscle matrix protein remodeling and protection against reinjury, which suggests that a (so far undefined) period of vulnerability to reinjury may exist during the remodeling phases. The role of individual muscle matrix components and their spatial interaction during adaptation to eccentric contractions is an unexplored field in human skeletal muscle and may provide insight into the optimal timing of rest vs. return to activity after muscle injury.

Effect of low-intensity therapeutic ultrasound on wound healing in rats subjected to third-degree burns.

PURPOSE: To determine the effectiveness of low-intensity therapeutic ultrasound (LITUS) on wound healing in rats with third-degree burns. METHODS: Twenty rats were divided into the Control Group that comprised four rats without third-degree burns that did not undergo LITUS, the Burned Group (BG), comprising eight rats with third-degree burns that did not undergo LITUS, and the Burned with Treatment Group (BTG), comprising eight rats with third-degree burns that were administered LITUS. LITUS began 24 h after injury and involved daily applications for 8 min at 0.1 W/cm2 for 14 days. RESULTS: The BTG lost less weight than the BG (Q=2.75; p<0.05). No visible differences were apparent among the groups' lesions on day 4. By the end of treatment, wound healing was more evident in the BTG. No statistically significant differences were found between the BG and the BTG in relation to the parameters measured using the histological changes in burn wound healing scoring system. CONCLUSION: The LITUS protocol applied to the animals with third-degree burns accelerated the formation of fibrin-leukocyte crusts and significantly reduced weight loss. However, burn wound healing was not accelerated.

Effect of low-intensity therapeutic ultrasound on wound healing in rats subjected to third-degree burns

PURPOSE: To determine the effectiveness of low-intensity therapeutic ultrasound (LITUS) on wound healing in rats with third-degree burns. METHODS: Twenty rats were divided into the Control Group that comprised four rats without third-degree burns that did not undergo LITUS, the Burned Group (BG), comprising eight rats with third-degree burns that did not undergo LITUS, and the Burned with Treatment Group (BTG), comprising eight rats with third-degree burns that were administered LITUS. LITUS began 24 h after injury and involved daily applications for 8 min at 0.1 W/cm2 for 14 days. RESULTS: The BTG lost less weight than the BG (Q=2.75; p<0.05). No visible differences were apparent among the groups' lesions on day 4. By the end of treatment, wound healing was more evident in the BTG. No statistically significant differences were found between the BG and the BTG in relation to the parameters measured using the histological changes in burn wound healing scoring system. CONCLUSION: The LITUS protocol applied to the animals with third-degree burns accelerated the formation of fibrin-leukocyte crusts and significantly reduced weight loss. However, burn wound healing was not accelerated.

Cómo puede afectar el componente genético la lesionabilidad de los deportistas / How the genetic component can affect the susceptibility to injury in athletes

El mundo del deporte y de la alta competición comporta un considerable riesgo de sufrir lesiones por su nivel de exigencia. Los programas de prevención son el principal objetivo a desarrollar y profundizar para minimizar el efecto de los factores de riesgo y evitar una elevada incidencia de lesiones y/o intentar disminuir la severidad de las mismas. El origen multifactorial de las lesiones complica la identificación de factores de riesgo, y es la suma de dichos factores y su interacción la que predispone al deportista a sufrir lesiones y a que se produzcan de una manera determinada. En los últimos años ha empezado a aflorar la importancia del componente genético de cada individuo como posible causa de predisposición lesional.En este trabajo se hace una revisión de los estudios genéticos realizados hasta la actualidad en relación a las lesiones del tejido conectivo y se proponen líneas futuras de investigación que permitirían desarrollar programas de entrenamiento más personalizados y especificar terapias preventivas a fin de reducir el riesgo lesional

The prevention, diagnosis and treatment of injuries are key factors in the daily practice of sports medicine, due to their great importance in high-level sports. The main aim of prevention programs is to minimize the effect of risk factors, avoid a high incidence of injury and to decrease injury severity. The multifactorial origin of injuries complicates the identification of risk factors (extrinsic and intrinsic), and taken together, these factors and their interaction predisposes the athlete to injuries. In recent years, the importance of the genetic component of each individual has begun to emerge as a possible cause of susceptibility to injury. In this article, a review is presented on genetic studies related to connective tissue repair or regeneration and to pave the way to future Sports Medicine research. This information could be very useful in order to individualize injury prevention strategies and to optimize the therapeutic and rehabilitation process after injuries

The future of bioactive ceramics.

Two important worldwide needs must be satisfied in the future; (1) treatment of the deteriorating health of an aging population and, (2) decreasing healthcare costs to meet the needs of an increased population. The ethical and economic dilemma is how to achieve equality in quality of care while at the same time decreasing cost of care for an ever-expanding number of people. The limited lifetime of prosthetic devices made from first-generation nearly inert biomaterials requires new approaches to meet these two large needs. This paper advises an expanded emphasis on: (1) regeneration of tissues and (2) prevention of tissue deterioration to meet this growing need. Innovative use of bioactive ceramics with genetic control of in situ tissue responses offers the potential to achieve both tissue regeneration and prevention. Clinical success of use of bioactive glass for bone regeneration is evidence that this concept works. Likewise the use of micron sized bioactive glass powders in a dentifrice for re-mineralization of teeth provides evidence that prevention of tissue deterioration is also possible. This opinion paper outlines clinical needs that could be met by innovative use of bioactive glasses and ceramics in the near future; including: regeneration of skeletal tissues that is patient specific and genetic based, load-bearing bioactive glass-ceramics for skeletal and ligament and tendon repair, repair and regeneration of soft tissues, and rapid low-cost analysis of human cell-biomaterial interactions leading to patient specific diagnoses and treatments using molecularly tailored bioceramics.

Effects of gamma irradiation on collagen damage and remodeling.

PURPOSE: To evaluate the dose-time dependences of structural changes occurring in collagen within 24 hours to three months after gamma-irradiation at doses from 2-40 Gy in vivo. MATERIALS AND METHODS: Rat's tail tendon was chosen as in vivo model, with its highly ordered collagen structure allowing the changes to be interpreted unambiguously. Macromolecular level (I) was investigated by differential scanning calorimetry (DSC); fibers and bundles level (II) by laser scanning microscopy (LSM), and bulk tissue microstructural level (III) by cross-polarization optical coherence tomography (CP-OCT). RESULTS: For (I), the formation of molecular cross-links and breaks appeared to be a principal mechanism of collagen remodeling, with the cross-links number dependent on radiation dose. Changes on level (II) involved primary, secondary and tertiary bundles splitting in a day and a week after irradiation. Bulk collagen microstructure (III) demonstrated early widening of the interference fringes on CP-OCT images observed to occur in the tendon as result of this splitting. At all three levels, the observed collagen changes demonstrated complete remodeling within ∼ a month following irradiation. CONCLUSION: The time course and dose dependencies of the observed collagen changes at different levels of its hierarchy further contribute to elucidating the role of connective tissue in the radiotherapy process.

Acupuncture increases the diameter and reorganisation of collagen fibrils during rat tendon healing.

BACKGROUND: Our previous study showed that electroacupuncture (EA) increases the concentration and reorganisation of collagen in a rat model of tendon healing. However, the ultrastructure of collagen fibrils after acupuncture is unknown. OBJECTIVES: To assess the effect of acupuncture protocols on the ultrastructure of collagen fibrils during tendon healing. METHODS: Sixty-four rats were divided into the following groups: non-tenotomised (normal group), tenotomised (teno group), tenotomised and subjected to manual acupuncture at ST36 (ST36 group), BL57 (BL57 group) and ST36+BL57 (SB group) and EA at ST36+BL57 (EA group). The mass-average diameter (MAD) and the reorganisation of collagen fibril diameters were determined during the three phases of tendon healing (at 7, 14 and 21 days). RESULTS: The MAD increased during the three phases of healing in the SB group. In the EA group, MAD increased initially but was reduced at day 21. The reorganisation of collagen fibrils was improved in the EA and SB groups at days 14 and 21, respectively. EA at day 21 appeared to reduce the reorganisation. CONCLUSIONS: These results indicate that the use of EA up to day 14 and manual acupuncture at ST36+BL57 up to day 21 improve the ultrastructure of collagen fibrils, indicating strengthening of the tendon structure. These data suggest a potential role for acupuncture in rehabilitation protocols.

Transforming growth factor-ß (TGF-ß) expression is increased in the subsynovial connective tissue in a rabbit model of carpal tunnel syndrome.

Carpal tunnel syndrome (CTS) is an idiopathic disease that results from increased fibrosis of the subsynovial connective tissue (SSCT). A recent study found overexpression of both transforming growth factor-ß (TGF-ß) and connective tissue growth factor (CTGF) in the SSCT of CTS patients. This study investigated TGF-ß and CTGF expression in a rabbit model of CTS, in which SSCT fibrosis is induced by a surgical injury. Levels of TGF-ß1 and CTGF at 6, 12, 24 weeks after injury were determined by immunohistochemistry A significant increase in TGF-ß1 and a concomitant significant increase in CTGF were found at 6 weeks, in addition to higher cell density compared to normal (all p<0.05), Interestingly, CTGF expression was reduced at 12 and 24 weeks, suggesting that an initial insult results in a time limited response. We conclude that this rabbit model mimics the fibrosis found in human CTS, and may be useful to study pathogenetic mechanisms of CTS in vivo.

Cambios conceptuales en la medicina deportiva actual / No disponible

No disponible

Musculotendon variability influences tissue strains experienced by the biceps femoris long head muscle during high-speed running.

The hamstring muscles frequently suffer injury during high-speed running, though the factors that make an individual more susceptible to injury remain poorly understood. The goals of this study were to measure the musculotendon dimensions of the biceps femoris long head (BFlh) muscle, the hamstring muscle injured most often, and to use computational models to assess the influence of variability in the BFlh's dimensions on internal tissue strains during high-speed running. High-resolution magnetic resonance (MR) images were acquired over the thigh in 12 collegiate athletes, and musculotendon dimensions were measured in the proximal free tendon/aponeurosis, muscle and distal free tendon/aponeurosis. Finite element meshes were generated based on the average, standard deviation and range of BFlh dimensions. Simulation boundary conditions were defined to match muscle activation and musculotendon length change in the BFlh during high-speed running. Muscle and connective tissue dimensions were found to vary between subjects, with a coefficient of variation (CV) of 17±6% across all dimensions. For all simulations peak local strain was highest along the proximal myotendinous junction, which is where injury typically occurs. Model variations showed that peak local tissue strain increased as the proximal aponeurosis width narrowed and the muscle width widened. The aponeurosis width and muscle width variation models showed that the relative dimensions of these structures influence internal muscle tissue strains. The results of this study indicate that a musculotendon unit's architecture influences its strain injury susceptibility during high-speed running.