In studying the differentiation of stem cells along smooth muscle lineage, smooth muscle cell (SMC) contractile proteins serve as markers for the relative state of maturation. Yet, recent evidence suggests that some SMC markers are probably expressed in multipotent mesenchymal stem cells (MSCs). Such a paradox necessitates investigations to re‐examine their role as differentiated markers in MSCs. We tried to detect the expression of four widely used SMC markers including α‐smooth muscle actin (α‐SMA), h1‐calponin, desmin and smooth muscle myosin heavy chain (SM‐MHC), as well as the other isoforms of calponin family in resting MSCs. Then we used three different conditions to initiate MSCs differentiation along SMC lineage, and examined the alternation of SMC markers expression at both the transcript level and protein level. Desmin and h1‐calponin are expressed in MSCs, in the presence or absence of SMC induction conditions. Moreover, MSCs are shown to express all known isoforms of calponin. Double‐staining reveals that h1‐calponin +/α‐SMA – cells constitute the majority of resting MSCs. Under differentiated conditions, expression of SM‐MHC was initiated and expression of α‐SMA was promoted. The expression of SM‐MHC and upregulation of α‐SMA are relatively reliable indications of a mature smooth muscle phenotype in MSCs. Given that the cells are particularly rich in calponins expression, we postulate possible roles of these proteins in regulating cellular function by taking part in actin cytoskeleton and signaling. These findings imply that an extensive study of the cell physiology of MSCs should focus on the functional roles for these proteins, rather than simply regard them as differentiated markers.

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Lesion of ossicular chain is a common ear disease impairing the sense of hearing. A comprehensive numerical model of human ear can provide better understanding of sound transmission. In this study, we propose a three-dimensional finite element model of human ear that incorporates the canal, tympanic membrane, ossicular bones, middle ear suspensory ligaments/muscles, middle ear cavity and inner ear fluid. Numerical analysis is conducted and employed to predict the effects of middle ear cavity, malleus handle defect, hypoplasia of the long process of incus, and stapedial crus defect on sound transmission. The present finite element model is shown to be reasonable in predicting the ossicular mechanics of human ear.

Nasal obstruction frequently has been associated with obstructive sleep apnea (OSA). Although correction of an obstructed nasal airway is considered an important component in OSA treatment, the effect of nasal surgery on OSA remains controversial. Variation in airway anatomy between before and after nasal surgery may cause significant differences in airflow patterns within the upper airway. In this paper, anatomically accurate models of the interaction between upper airway and soft palate were developed from prenasal and post-nasal surgery multidetector computed tomography data of a patient with OSA and nasal obstruction. Computational modeling for inspiration and expiration was performed by using fluid-structure interaction method. The airflow characteristics such as velocity, turbulence intensity and pressure drop, and displacement distribution of soft palate are selected for comparison. Airway resistances significantly decrease after the nasal surgery, especially in the velopharynx region because of an enlarged pharyngeal cavity and a reduced upstream resistance. Meanwhile, the decreased aerodynamic force would result in a smaller displacement of soft palates, which would lead to slight impact of the soft palate motion on the airflow characteristics. The present results suggest that airflow distribution in the whole upper airway and soft palate motions have improved following nasal surgery.