No abstract

The masticatory system is a complex and highly organized group of structures, including craniofacial bones (maxillae and mandible), muscles, teeth, joints, and neurovascular elements. While the musculoskeletal structures of the head and neck are known to have a different embryonic origin, morphology, biomechanical demands, and biochemical characteristics than the trunk and limbs, their particular molecular basis and cell biology have been much less explored. In the last decade, the concept of muscle-bone crosstalk has emerged, comprising both the loads generated during muscle contraction and a biochemical component through soluble molecules. Bone cells embedded in the mineralized tissue respond to the biomechanical input by releasing molecular factors that impact the homeostasis of the attaching skeletal muscle. In the same way, muscle-derived factors act as soluble signals that modulate the remodeling process of the underlying bones. This concept of muscle-bone crosstalk at a molecular level is particularly interesting in the mandible, due to its tight anatomical relationship with one of the biggest and strongest masticatory muscles, the masseter. However, despite the close physical and physiological interaction of both tissues for proper functioning, this topic has been poorly addressed. Here we present one of the most detailed reviews of the literature to date regarding the biomechanical and biochemical interaction between muscles and bones of the masticatory system, both during development and in physiological or pathological remodeling processes. Evidence related to how masticatory function shapes the craniofacial bones is discussed, and a proposal presented that the masticatory muscles and craniofacial bones serve as secretory tissues. We furthermore discuss our current findings of myokines-release from masseter muscle in physiological conditions, during functional adaptation or pathology, and their putative role as bone-modulators in the craniofacial system. Finally, we address the physiological implications of the crosstalk between muscles and bones in the masticatory system, analyzing pathologies or clinical procedures in which the alteration of one of them affects the homeostasis of the other. Unveiling the mechanisms of muscle-bone crosstalk in the masticatory system opens broad possibilities for understanding and treating temporomandibular disorders, which severely impair the quality of life, with a high cost for diagnosis and management.

a Synthesis of inorganic particles using routes inspired by biomineralization is a goal of growing interest.Recently it was demonstrated that the size and geometry of crystallization sites are as important as the structure of charged templating surfaces to obtain particles with controlled features. Most biominerals are formed inside restricted, constrained or confined spaces where at least parts of the boundaries are cell membranes containing phospholipids. In this study, we used a gas diffusion method to determine the effect of different lecithin media on the crystallization of CaCO 3 and to evaluate the influence of the spatial arrangement of lecithin molecules on templating CaCO 3 crystal formation. By using inorganic synthesis, Raman spectroscopy, dynamic light scattering, electrochemical methods and scanning electron microscopy, we showed that the occurrence of surface-modified calcite crystals and diverse textured vaterite crystals reflects the geometry and spatial distribution of aqueous constrained spaces due to the lecithin assembly controlled by lecithin concentration in an ionized calcium chloride solution under a continuous CO 2 diffusion atmosphere. This research shows that by tailoring the assembly of lecithin molecules, as micelles or reversed micelles, it is possible to modulate the texture, polymorphism, size and shape of calcium carbonate crystals.

Bilateral pudendal nerves block oriented by nerve stimulator provides excellent analgesia with low need for opioids, without local or systemic complications and without urinary retention. Controlled studies might be able to show whether this should be the first analgesic option for hemorrhoidectomies. Perineal anesthesia lasting 20.21 hours shall induce further studies with stimulator-oriented pudendal block.

Calreticulin is an endoplasmic reticulum-resident, calcium-binding, stress-produced, chaperone protein that serves multiple functions and is widely distributed in eukaryotic cells. Exogenously applied recombinant calreticulin solution, markedly enhanced the rate and quality of skin wound healing. These modulatory effects are more efficient than commercially available topic platelet-derived growth factor ointments (Regranex). Trypanosoma cruzi calreticulin is more effective in equimolar terms to human counterpart in accelerating skin wound healing. While the effect of externally added recombinant parasite calreticulin on wound healing has been reported, the domains responsible for these modulatory effects have not yet been established. Here, recombinant parasite calreticulin and some of its domains were tested to assess their influence in increasing proliferation and migration of fibroblasts in vitro and rat skin wound healing in vivo. Herein, we propose that Trypanosoma cruzi whole calreticulin or some of its domains are differentially involved in the modulation of wound-healing cell migration and proliferation, and cosmetic outcome. Therefore, precise combination of the parasite protein and its domains could allow us to tailor-specific desired effects during the skin wound-healing process.

JUSTIFICATIVA E OBJETIVOS:Este estudo avaliou a eficácia da injeção única de bupivacaína a 0,25% no compartimento do psoas ou perivascular inguinal por meio do estimulador de nervos periféricos para analgesia pós-operatória em pacientes submetidos a intervenções cirúrgicas ortopédicas. MÉTODO:Cem pacientes receberam bloqueio do plexo lombar através do compartimento do psoas e foram comparados com 100 pacientes que receberam bloqueio do plexo lombar via perivascular inguinal, identificados pelo estimulador de nervos periféricos com a injeção de 40 mL bupivacaína a 0,25% sem epinefrina. A analgesia nos nervos ilioinguinal, genitofemoral, cutâneo femoral lateral, femoral e obturatório foi avaliada 4, 8,12, 16, 20 e 24 horas após o final da intervenção cirúrgica. A intensidade da dor foi também avaliada no mesmo período. A quantidade de opióides administrada no pós-operatório foi anotada. Em cinco pacientes de cada grupo, estudo radiográfico com contraste não-iônico foi realizado para avaliar a dispersão da solução anestésica. RESULTADOS:Os nervos ilioinguinal, genitofemoral, cutâneo femoral lateral, femoral e obturatório foram bloqueados em 92% dos pacientes no compartimento do psoas versus 62% no bloqueio perivascular inguinal. O bloqueio do plexo lombar reduziu a necessidade de opióides e 42% dos pacientes submetidos ao bloqueio do compartimento do psoas e 36% dos pacientes no bloqueio inguinal não necessitaram de analgésico adicional no pós-operatório. A duração da analgesia foi em torno de 21 horas com bloqueio do compartimento do psoas e 15 horas com bloqueio perivascular inguinal. CONCLUSÕES:O bloqueio do compartimento do psoas e perivascular inguinal é uma excelente técnica para analgesia pós-operatória em intervenções cirúrgicas ortopédicas reduzindo a necessidade de opióides. Este estudo mostrou que a injeção no compartimento do psoas foi mais fácil e mais efetiva no bloqueio dos cinco nervos do plexo lombar.Unitermos: ANALGESIA: pós-operatória; ANESTÉSICOS, Local: bupivacaína; TÉCNICAS ANESTÉSICAS, Regional: compartimento do psoas, bloqueio perivascular inguinal. SUMMARY BACKGROUND AND OBJECTIVES:This study evaluated the efficacy of a single injection of 0.25% bupivacaine in the psoas compartment or inguinal paravascular for postoperative analgesia in patients undergoing orthopedic surgeries using a peripheral nerve stimulator. METHODS:One hundred patients who had a lumbar plexus block through the psoas compartment were compared to 100 patients who had an inguinal paravascular block, using a peripheral nerve stimulator, with 40 mL of 0.25% bupivacaine. The analgesia of the ilioinguinal, genitofemoral, lateral femoral cutaneous, femoral, and obturator nerves was assessed 4, 8,12, 16, 20, and 24 hours after the end of the surgical procedure. Pain severity was also evaluated in the same period. The amount of opioids administered in the postoperative period was recorded. A radiological study with nonionic contrast was done in five patients in each group to evaluate the dispersion of the anesthetic. RESULTS:T...

Artículo de publicación ISITibiotarsal fractures are common in birds because in most birds this is the longest, most exposed bone in the leg. Transverse fractures are most common and rotational and shear forces must be stabilized in order to achieve good bone regeneration. A 230g male Slender-billed Parakeet or Choroy parakeet (Enicognathus leptorhynchus), with more than five years of age, was received with non-weight bearing lameness with 24 hours duration. X-rays were taken, and these revealed a closed, complete, non-comminuted transverse fracture of the distal diaphysis of the left tibiotarsal bone. Fixation was planned with 10-minute fast-setting epoxy putty. In order to assess the temperature of polymerization of the epoxy dough and the possibility of heat-bone necrosis, the temperature was recorded every 30 seconds for 12 minutes with three different amounts of the epoxy material in an ex vivo test. The temperature of the pieces reached a peak of 50-60°C, where the highest peak corresponds to the highest amount of material. When approximately 6g of putty were used, the peak temperature reached only 51°C. This peak changed to 58°C when 4 times more epoxy was mixed and measured. If the temperature of the pins inserted in the bone exceeds 70°C, bone necrosis could occur. In light of these results, the fracture was treated with 6 g of epoxy putty that was allowed to polymerize over a 1A 2/2 external skeletal fixation, with 1-mm pins bent at 90° and joined together with cerclage wire. At 6 weeks after surgery the bird had formed a good primary bone callus, and the external fixators were therefore removed. With this approach a satisfactory recovery of the patient was achieved with normal use of the affected limb

The masticatory system is a coordinated machine, highly adaptable to environmental demands. Increased levels of interleukin 6 (IL6) in the synovial fluid have been associated with temporomandibular disorders. Although they are mostly suggested released from inflammatory cells, it has been reported that IL6 is also a “myokine”, released by muscle cells during activity or in pathological processes. A pivotal role of IL6 in skeletal muscle and bone has been suggested, being related to both anabolic and catabolic processes. We here propose that IL6 is released by masseter muscle during activity and that a deregulated increased level of muscle‐derived IL6 correlates to the musculoskeletal impairment in animal models of masticatory muscles unloading. We induced masseter muscle hypofunction in male BalbC mice (8 weeks old) by either soft diet (SD) consumption (pellet:water=1:3) or unilateral paralysis of masseter muscles injected with Botulinum Toxin Type A (BoNTA; 0.2U/10 µL). Both masseter muscles and mandibles were dissected after 2‐14 days for morphology, histology, or molecular measurements. Masseter muscles were electrically stimulated (ES) in vitro for demonstrating activity‐evoked changes in IL6 expression and secretion. All procedures were approved by the Institutional Committee for the Care and Use of Animals of the Universidad de Chile (# 17011‐OD‐UCH). We demonstrated that IL6 is expressed and released from masseter muscle after ES, in a frequency‐dependent manner. IL6 expression after ES requires the release of ATP from muscle, and activation of P2Y/P2X receptors. In the animal models of SD or BoNTA, atrophy of masseter muscle is observed (reduction of muscle volume, mass, and fibers diameter, as well as increased expression of Atrogin‐1/MURF‐1/Myogenin) after 7‐14 days. Increased resting levels of extracellular ATP and IL6 expression were detected in masseter muscles of SD‐fed mice and BoNTA‐injected muscles. In the later, an increased expression of ATP releaser molecules (pannexin 1, connexin 43‐45) was reported, as well as increased levels of ATP receptors P2Y2 and P2X7. Interestingly, the metabolization of extracellular ATP using Apyrase restored the resting levels of IL6 expression in masseter muscles derived from SD‐fed mice. Also, changes in morphology and bone loss were observed in mandibular condyles associated with BoNTA‐injected masseter muscles. We here report that IL6 is expressed and released by masseter muscles, either at rest and after muscle activity. Moreover, masseter muscle hypofunction induces an overactivation of the extracellular ATP‐IL6 axis in muscles. We are currently addressing if this deregulated signaling is involved in the muscle atrophy and bone loss evoked by masticatory muscle unloading. Understanding the molecular pathways involved in muscle‐bone crosstalk at the masticatory system will contribute to propose strategies to avoid non‐desirable effects in pathologies or clinical interventions presenting muscle unloading.