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.