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Biomedical subjects

C W Li

Publications and source records attributed to C W Li.

48 records · Page 3Linked to original sources
PubMed1978

The fate mapping of the eleventh and twelfth day mouse otocyst: an in vitro study of the sites of origin of the embryonic inner ear sensory structures.

An experiment was undertaken to determine which sensory structures of the mouse embryo inner ear developed from what portion of the mouse otocyst. Otocysts of gestation days 10, 11, 12, and 13 were divided by surgical dissection into six anatomical groups: dorsal, ventral, anterior, posterior, medial and lateral halves. They were organ cultured separately. After a period of ten days, the explanted tissues were harvested and processed histologically for microscopic analysis. The surgical control specimens fixed at the time of explantation were composed of undifferentiated ectodermal cells for tissues of gestation days 10, 11, and 12. Otocysts of gestation days 11, and 12 showed, during the course of their subsequent growth, that the three semicircular ducts and their associated cristae developed from the dorsal and lateral halves. Only the anterior and posterior canals and cristae originated from the medial portion. The posterior half gave rise to the posterior crista and the anterior half provided for the development of the anterior and lateral cristae. The cochlear duct and its sensory epithelium developed in all the anatomical groups except the dorsal half. The utricle developed in the dorsal section of the middle third of the otocyst, while the utricular macula developed in the anterior half of the same section of the otocyst. The saccule and its macula differentiated from the ventral section of the middle third of the anterior half.

Animals↗
PubMedDate not supplied

Influences on the coiling of the cochlea.

The growth and shape of the cochlea appears to be controlled by the formation of the cartilaginous capsule. Coiling of the cochlear duct is apparently the result of the physical barrier and support provided by the cartilage cells differentiating from mesenchyme surrounding the ventral portion of the otocyst. In addition, tissue interactions between this mesenchyme and the developing cochlear duct will influence the formation of the cartilaginous capsule and they may also be the origin of one of the controlling agents for the coiling mechanism.

Animals↗
PubMedDate not supplied

Structure and development of vestibular hair cells in the larval bullfrog.

Structure and development of hair cells in vestibular sensory organs of the larval bullfrog were examined with scanning electron microscopy. The larval vestibular sensory epithelia resembled those of the adult frog. Based on morphology of the ciliary tufts, seven hair cell types were identified. One of them, the type A hair cell, appears to be the morphogenetic precursor of other hair cell types. The size of the stereocilia of type A hair cells is comparable to the surrounding microvilli. The distribution of immature type A hair cells suggests that the periphery of the sensory epithelia is the principal growth zone and the site of formation of new hair cells. However, a far greater number of type A hair cells were found in high frequency sensitive sensory organs (sacculus, amphibian and basilar papillae) than low frequency sensitive vestibular sensory structures (canal cristae, utriculus and lagena). This phenomenon may suggest that the time period required for the maturation of type A hair cells to their ultimate hair cell types in the low frequency sensitive vestibular organs is shorter than in the high frequency sensory structures. It is also possible that the low frequency sensitive vestibular organs may have completed their morphogenetic development in the early larval stages, while morphogenesis of hair cells in the high frequency sensory structures continues throughout the lifetime of a bullfrog.

Animals↗
PubMedDate not supplied

Development of the cochlea and its coiling mechanism.

The growth and shape of the membraneous labyrinth appears to be organized and restricted by the formation of the cartilaginous capsule. Coiling of the cochlear duct appears to be the result of the physical barrier and support provided by the cartilage cells differentiating from mesenchyme surrounding the otocyst. In addition, tissue interactions between this mesenchyme and the developing cochlear duct may be the source of a genetic message for the coiling mechanism.

Animals↗
PubMedDate not supplied

Phospholipid metabolites in 1H-decoupled 31P MRS in vivo in human cancer: implications for experimental models and clinical studies.

The use of 31P MRS in clinical cancer research has been hampered by both poor anatomic localization of spectra and poor resolution of overlapping signals. We found that accurate localization using 3D chemical shift imaging and improved resolution using 1H-decoupling and nuclear Overhauser-enhancement (NOE) increased signal-to-noise and permitted resolution of separate components within phosphomonoester (PME) and phosphodiester (PDE) regions. Fifty-three cancers of different types (lymphoma, sarcoma, adenocarcinoma) had the following common features: (1) phosphoethanolamine the dominant PME; (2) glycerophosphoethanolamine and -choline rarely detected; (3) a broad PDE signal probably from membrane phospholipids; and(4) prominent nucleoside triphosphates. 1H-decoupling with NOE-enhancement permitted us to obtain new information about in vivo metabolism in human cancers; generate new hypotheses and help guide development of experimental models appropriate to test them; and provide a firm basis with which to examine clinical uses of 31P MRS.

Humans↗