Engineered three-dimensional rabbit oral epithelial-mesenchymal-muscular hybrid sheets.

Regenerative muscles are required for swallowing and mastication, and are important for functional recovery from diseases involving oral muscular defects. Therefore, we generated three-layer hybrid sheets, similar to oral mucosal structures containing submucosal muscles, using rabbit oral mucosa epithelial, mesenchymal, and myoblastic progenitor cells, and examined the structural proteins. Each cell type was obtained from rabbit oral mucosa using enzymatic digestion. Isolated mesenchymal and myoblastic cells were multi-differentiated into osteoblasts, adipocytes, and chondrocytes or myotubes. Isolated epithelial cells were cultured on collagen gels containing isolated mesenchymal cells for 2 weeks, and these epithelial-mesenchymal cell sheets were laminated onto myoblastic cell sheets. The engineered hybrid sheets were multi-stratified in the epithelial and myoblastic layers in a time-dependent manner, expressing intermediate cytoskeletal filament proteins of epithelium and muscle. Hybrid sheets also expressed extracellular matrix basement membrane proteins. Immature cell markers for epithelial and myoblastic cells were observed continuously in hybrid sheet cultures. We established engineered three-dimensional rabbit oral mucosa hybrid sheets containing each immature cell type in vitro.

Desmin and nerve terminal expression during embryonic development of the lateral pterygoid muscle in mice.

OBJECTIVE: In adults, the lateral pterygoid muscle (LPM) is usually divided into the upper and lower head, between which the buccal nerve passes. Recent investigations have demonstrated foetal developmental changes in the topographical relationship between the human LPM and buccal nerve. However, as few studies have investigated this issue, we clarified the expression of desmin and nerve terminal distribution during embryonic development of the LPM in mice. METHODS: We utilized immunohistochemical staining and reverse transcription chain reaction (RT-PCR) to clarify the expression of desmin and nerve terminal distribution. RESULTS: We observed weak expression of desmin in the LPM at embryonic day (ED) 11, followed by an increase in expression from embryonic days 12-15. In addition, starting at ED 12, we observed preferential accumulation of desmin in the vicinity of the myotendinous junction, a trend that did not change up to ED 15. Nerve terminal first appeared at ED 13 and formed regularly spaced linear arrays at the centre of the muscle fibre by ED 15. The results of immunohistochemical staining agreed with those of RT-PCR analysis. CONCLUSION: We found that desmin accumulated in the vicinity of the myotendinous junction starting at ED 12, prior to the onset of jaw movement. We speculate that the accumulation of desmin is due to factors other than mechanical stress experienced during early muscle contraction. Meanwhile, the time point at which nerve terminals first appeared roughly coincided with the onset of jaw movement.

Fetal anatomy of the upper pharyngeal muscles with special reference to the nerve supply: is it an enteric plexus or simply an intramuscular nerve?

We examined pharyngeal nerve courses in paraffin-embedded sagittal sections from 10 human fetuses, at 25-35 weeks of gestation, by using S100 protein immunohistochemical analysis. After diverging from the glossopharyngeal and vagus nerves at the level of the hyoid bone, the pharyngeal nerves entered the constrictor pharyngis medius muscle, then turned upward and ran superiorly and medially through the constrictor pharyngis superior muscle, to reach either the levator veli palatini muscle or the palatopharyngeus muscle. None of the nerves showed a tendency to run along the posterior surface of the pharyngeal muscles. Therefore, the pharyngeal nerve plexus in adults may become established by exposure of the fetal intramuscular nerves to the posterior aspect of the pharyngeal wall because of muscle degeneration and the subsequent rearrangement of the topographical relationship between the muscles that occurs after birth.

Morphology of plantar interdigital neuroma: a comparative cadaveric study of elderly Finnish and Japanese individuals.

To examine morphological differences in Morton's interdigital neuroma between two elderly human populations, we conducted comparative study using 40 Japanese (27 males, 13 females; mean age, 81.2 years) and 21 Finnish (6 males, 15 females; mean age, 80.5 years) cadavers. We defined the neuroma as a thickening of the nerve of at least two-fold relative to the non-pathological proximal part. The incidence of this neuroma was 25% (10/40) in the Japanese and 33.3% (7/21) in the Finnish cadavers. Moderate or severe hallux valgus (with an angle of more than 20 degrees) was seen in half of the 40 Japanese cadavers (7 males, 13 females), but was absent in the Finnish cadavers. Such hallux valgus was present in 7 (5 males, 2 females) of the 10 Japanese cadavers with neuroma. Moreover, in 2 Japanese cadavers, a paper-like, specialized type of neuroma was associated with the deformity. Pathogenesis of Morton's neuroma might be different between human populations with or without hallux valgus.

Site-dependent difference in the density of sympathetic nerve fibers in muscle-innervating nerves: a histologic study using human cadavers

The autonomic nerve supply of skeletal muscle has become a focus of interest because it is closely related to the adaptation of energy metabolism with aging. However, there is no comprehensive information concerning the sympathetic nerves present in muscle-innervating nerves (muscle-nerve). At the point of entry of muscle-nerves into 8 striated muscles (the soleus, extensor carpi radialis, infraspinatus, genioglossus, extra- ocular medial rectus, temporalis, lateral pterygoid, and digastricus anterior belly) in 15 cadavers of elderly people, we counted both tyrosine hydroxylasepositive nerve fibers (TH- fibers) and motor nerve fibers to estimate the ratio of THfiber/ motor fibers. The 3 limb muscles were found to have a high ratio (soleus, 58%; infraspinatus; 45%; extensor, 36%), whereas the 4 head muscles (digastricus, 23%; genioglossus, 15%; temporalis, 10%; lateral pterygoid, 6%; medial rectus, 1%) had relatively low ratios. The site- dependent characteristics of the THfibers seemed to reflect their commitment to muscle activity. However, some discrepant characteristics were noted: 1) In spite of the tonic and continuous activity required for both the genioglossus and infraspinatus, the proportions of TH-fibers were quite different between the tongue and the shoulder muscles; 2) Likewise, the soleus and extra-ocular rectus showed a considerable difference, even though rapid and phasic contraction is essential for both muscles. Rather than reflecting the influence of postnatal functional demand, these site- dependent characteristics might develop as a result of differences in sympathetic innervation of the striated muscles during fetal development, i.e., a short course along the arteries feeding the head muscles, or a long course along the muscle-nerves to the limb muscles (AU)

No disponible