SciCombinator

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Concept: Soft tissue

174

Cycling has been shown to confer considerable benefits in terms of health, leading to reductions in death rates principally due to cardiovascular improvements and adaptation. Given the disparity between the benefits of cycling on cardiovascular fitness and previous research finding that cycling may not be beneficial for bone health, Hugo Olmedillas and colleagues performed a systematic review of the literature. They concluded that road cycling does not appear to confer any significant osteogenic benefit. They postulate that the cause of this is that, particularly at a competitive level, riders spend long periods of time in a weight-supported position on the bike. Training programs may be supplemented with impact loading to preserve bone health; however, the small increased risk of soft tissue injury must also be considered. See related research article http://www.biomedcentral.com/1741-7015/10/168.

Concepts: Academic publishing, Research, Tissues, Cycling, Soft tissue, Position, Employee benefit, Soft tissue injury

168

Mechanics is an important component in the regulation of cell shape, proliferation, migration and differentiation during normal homeostasis and disease states. Biomaterials that match the elastic modulus of soft tissues have been effective for studying this cell mechanobiology, but improvements are needed in order to investigate a wider range of physicochemical properties in a controlled manner. We hypothesized that polydimethylsiloxane (PDMS) blends could be used as the basis of a tunable system where the elastic modulus could be adjusted to match most types of soft tissue. To test this we formulated blends of two commercially available PDMS types, Sylgard 527 and Sylgard 184, which enabled us to fabricate substrates with an elastic modulus anywhere from 5 kPa up to 1.72 MPa. This is a three order-of-magnitude range of tunability, exceeding what is possible with other hydrogel and PDMS systems. Uniquely, the elastic modulus can be controlled independently of other materials properties including surface roughness, surface energy and the ability to functionalize the surface by protein adsorption and microcontact printing. For biological validation, PC12 (neuronal inducible-pheochromocytoma cell line) and C2C12 (muscle cell line) were used to demonstrate that these PDMS formulations support cell attachment and growth and that these substrates can be used to probe the mechanosensitivity of various cellular processes including neurite extension and muscle differentiation.

Concepts: Muscle, Cellular differentiation, Cell culture, Tissues, Materials science, Tissue, Soft tissue, Young's modulus

168

The aim of this study was to quantify anteroposterior facial soft tissue changes with respect to underlying skeletal movements after Le Fort I maxillary advancement and mandibular setback surgery with sagittal split osteotomy in Class III skeletal deformity by using lateral cephalograms taken before and after the operation. The material consisted of 31 patient (15 female, 16 male cases, mean age was 26.7 ± 2.5 years) with Class III skeletal deformity. All patients were treated by Le Fort I maxillary advancement and mandibular setback surgery with sagittal split osteotomy. Lateral cephalograms were taken before and 1.4 ± 0.3 years after surgery. Wilcoxon test was used to compare the pre- and post-surgical measurements. Pearson correlation test was used to compare the relationships between the skeletal, dental and facial soft tissue changes. In the maxilla, the APOINTAP (the anteroposterior position of A point) and ITIPAP (the anteroposterior position of upper incisor) showed significant protractions (-3.19 ± 3.63, and -3.19 ± 4.52, p < 0.01). In the mandible, the L1TIPAP (the anteroposterior position of lower incisor, -3.20 ± 5.83, p < 0.01), L1TIPSI (the superoinferior position of lower incisor, -2.43 ± 10.31, p < 0.05), BPOINTSP (the superoinferior position of B point, -2.28 ± 12.51, p < 0.05) and BPOINTAP (the anteroposterior position of B point, -3.19 ± 9.31, p < 0.01) showed significant retractions and upper positions after bimaxillary surgery. The insignificant decrease in soft tissue Pog-Vert distance was correlated the significant upper position of B point and lower incisor (r: 0.851, p < 0.001 and r: 0.842, p < 0.001).

Concepts: Spearman's rank correlation coefficient, Mandible, Tissues, Correlation and dependence, Pearson product-moment correlation coefficient, Soft tissue, Karl Pearson, Maxilla

166

Soft tissue sarcomas comprise approximately 1% of all adult solid malignancies. While chemotherapy is the mainstay of treatment for patients with metastatic or inoperable disease, overall survival for these patients is approximately 12 months, highlighting the need for novel agents. Both laboratory and clinical data have suggested that antiangiogenic agents may have a role in the treatment of soft tissue sarcomas. Pazopanib is a multitargeted receptor tyrosine kinase inhibitor with antiangiogenic activity. The randomized, double-blind, placebo-controlled, Phase III PALETTE (pazopanib for metastatic soft-tissue sarcoma) study demonstrated improved progression-free survival in patients receiving pazopanib compared with placebo. In this review, we discuss the rationale and clinical evidence for the use of pazopanib in the treatment of metastatic and inoperable soft tissue sarcomas.

Concepts: Cancer, Signal transduction, Soft tissue sarcoma, Types of cancer, Lymphoma, Soft tissue, Sarcoma, Alveolar soft part sarcoma

107

Body shape is a fundamental expression of organismal biology, but its quantitative reconstruction in fossil vertebrates is rare. Due to the absence of fossilized soft tissue evidence, the functional consequences of basal paravian body shape and its implications for the origins of avians and flight are not yet fully understood. Here we reconstruct the quantitative body outline of a fossil paravian Anchiornis based on high-definition images of soft tissues revealed by laser-stimulated fluorescence. This body outline confirms patagia-bearing arms, drumstick-shaped legs and a slender tail, features that were probably widespread among paravians. Finely preserved details also reveal similarities in propatagial and footpad form between basal paravians and modern birds, extending their record to the Late Jurassic. The body outline and soft tissue details suggest significant functional decoupling between the legs and tail in at least some basal paravians. The number of seemingly modern propatagial traits hint that feathering was a significant factor in how basal paravians utilized arm, leg and tail function for aerodynamic benefit.

Concepts: DNA, Evolution, Bird, Tissues, Soft tissue, Paleontology, Dinosaur, Jurassic

53

Chronic fatigue syndrome (CFS) is a complex, multisystem disorder that can be disabling. CFS symptoms can be provoked by increased physical or cognitive activity, and by orthostatic stress. In preliminary work, we noted that CFS symptoms also could be provoked by application of longitudinal neural and soft tissue strain to the limbs and spine of affected individuals. In this study we measured the responses to a straight leg raise neuromuscular strain maneuver in individuals with CFS and healthy controls. We randomly assigned 60 individuals with CFS and 20 healthy controls to either a 15 minute period of passive supine straight leg raise (true neuromuscular strain) or a sham straight leg raise. The primary outcome measure was the symptom intensity difference between the scores during and 24 hours after the study maneuver compared to baseline. Fatigue, body pain, lightheadedness, concentration difficulties, and headache scores were measured individually on a 0-10 scale, and summed to create a composite symptom score. Compared to individuals with CFS in the sham strain group, those with CFS in the true strain group reported significantly increased body pain (P = 0.04) and concentration difficulties (P = 0.02) as well as increased composite symptom scores (all P = 0.03) during the maneuver. After 24 hours, the symptom intensity differences were significantly greater for the CFS true strain group for the individual symptom of lightheadedness (P = 0.001) and for the composite symptom score (P = 0.005). During and 24 hours after the exposure to the true strain maneuver, those with CFS had significantly higher individual and composite symptom intensity changes compared to the healthy controls. We conclude that a longitudinal strain applied to the nerves and soft tissues of the lower limb is capable of increasing symptom intensity in individuals with CFS for up to 24 hours. These findings support our preliminary observations that increased mechanical sensitivity may be a contributor to the provocation of symptoms in this disorder.

Concepts: Symptoms, Symptom, Tissues, Soft tissue, Fatigue, Post-concussion syndrome, Chronic fatigue syndrome, Straight leg raise

50

The flexibility and posture of the neck in sauropod dinosaurs has long been contentious. Improved constraints on sauropod neck function will have major implications for what we know of their foraging strategies, ecology and overall biology. Several hypotheses have been proposed, based primarily on osteological data, suggesting different degrees of neck flexibility. This study attempts to assess the effects of reconstructed soft tissues on sauropod neck flexibility through systematic removal of muscle groups and measures of flexibility of the neck in a living analogue, the ostrich (Struthio camelus). The possible effect of cartilage on flexibility is also examined, as this was previously overlooked in osteological estimates of sauropod neck function. These comparisons show that soft tissues are likely to have limited the flexibility of the neck beyond the limits suggested by osteology alone. In addition, the inferred presence of cartilage, and varying the inter-vertebral spacing within the synovial capsule, also affect neck flexibility. One hypothesis proposed that flexibility is constrained by requiring a minimum overlap between successive zygapophyses equivalent to 50% of zygapophyseal articular surface length (ONP50). This assumption is tested by comparing the maximum flexibility of the articulated cervical column in ONP50 and the flexibility of the complete neck with all tissues intact. It is found that this model does not adequately convey the pattern of flexibility in the ostrich neck, suggesting that the ONP50 model may not be useful in determining neck function if considered in isolation from myological and other soft tissue data.

Concepts: Bone, Soft tissue sarcoma, Tissues, Soft tissue, Synovial joint, Ostrich, Struthio, Somali Ostrich

37

Soft fibrillar bone tissues were obtained from a supraorbital horn of Triceratops horridus collected at the Hell Creek Formation in Montana, USA. Soft material was present in pre and post-decalcified bone. Horn material yielded numerous small sheets of lamellar bone matrix. This matrix possessed visible microstructures consistent with lamellar bone osteocytes. Some sheets of soft tissue had multiple layers of intact tissues with osteocyte-like structures featuring filipodial-like interconnections and secondary branching. Both oblate and stellate types of osteocyte-like cells were present in sheets of soft tissues and exhibited organelle-like microstructures. SEM analysis yielded osteocyte-like cells featuring filipodial extensions of 18-20μm in length. Filipodial extensions were delicate and showed no evidence of any permineralization or crystallization artifact and therefore were interpreted to be soft. This is the first report of sheets of soft tissues from Triceratops horn bearing layers of osteocytes, and extends the range and type of dinosaur specimens known to contain non-fossilized material in bone matrix.

Concepts: Bone, Tissues, Soft tissue, Fossil, Dinosaur, Montana, Triceratops, Hell Creek Formation

28

Proportionality of the lower and middle thirds of the face is a key determinant of successful orthognathic treatment. A flatter profile and marked variance of the soft tissue envelope in the Japanese population complicates the accurate assessment of these proportions. This study aimed to identify gender differences and establish norms for Japanese young adults using the method of soft tissue cephalometric analysis (STCA) by Arnett et al (Am J Orthod Dentofacial Orthop 116:239, 1999).

Concepts: Sample size, Biology, Method acting, Sociology, Tissues, Japan, Soft tissue, Face

28

OBJECTIVES: Heterotopic ossification is defined as the abnormal formation of true bone within extra-skeletal soft tissues. It may be associated with a variety of clinical conditions, but is most frequently seen with musculoskeletal trauma, neurologic injury or genetic abnormalities. It has also been described in patients with chronic venous insufficiency; however, it often goes underdiagnosed due to chronic ulceration that masks exam findings. To date, few reports of heterotopic ossification due to chronic venous disease exist within the literature with the most recent dating back to the 1970s. METHODS: We present a case study of a man presenting with extensive leg ulceration and a history of chronic venous insufficency. He had a large non-healing venous stasis ulcer of the left lower extremity with extensive heterotopic ossification discovered intraoperatively. RESULTS: The patient was managed with serial wound debridement, innovative woundcare and eventual split thickness skin grafting that achieved limb salvage despite the complexity of his wound. CONCLUSIONS: Our discussion focuses on the epidemiology, pathophysiology, diagnostic work-up and management of heterotopic ossification in the setting of chronic venous insufficiency. We propose that heterotopic ossification be included in any future modifications of the clinical, aetiology, anatomy and pathophysiology system classification as a complication of chronic venous disease.

Concepts: Medicine, Epidemiology, Patient, Tissues, Soft tissue, Heterotopic ossification, Myositis ossificans, Chronic venous insufficiency