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At least 847 records · Page 47Linked to original sources
PubMed1994

Influence of cocaine and lidocaine on human nasal cilia. Beat frequency and harmony in vitro.

The effects of cocaine and lidocaine on ciliary beat frequency and ciliary beat harmony were studied in biopsy specimens of normal human nasal mucosa. Cocaine was investigated in increasing concentrations (0.875%, 1.75%, 3.5%, and 7%) in five samples; lidocaine (0.125%, 0.25%, 0.5%, 1%, and 2%), in four samples. Ciliary beat was recorded photoelectrically and the signal was analyzed. Cocaine was found to decrease ciliary beat frequency and ciliary beat harmony at concentrations of 1.75% and higher. Partially reversible ciliostasis was seen at 7%. Lidocaine was found to decrease ciliary beat frequency and ciliary beat harmony at concentrations of 0.25% and higher. Irreversible ciliostasis was seen at 2%. Cocaine and lidocaine affected ciliary beat frequency and ciliary beat harmony in the same way.

Cilia↗
PubMed1997

Myosin VIIa, the product of the Usher 1B syndrome gene, is concentrated in the connecting cilia of photoreceptor cells.

Usher syndrome is the most common form of combined deafness and blindness. The gene that is defective in Usher syndrome 1B (USH1B) encodes for an unconventional myosin, myosin VIIa. To understand the cellular function of myosin VIIa and why defects in it lead to USH1B, it is essential to determine the precise cellular and subcellular localization of the protein. We investigated the distribution of myosin VIIa in human and rodent photoreceptor cells and retinal pigment epithelium (RPE), primarily by immunoelectron microscopy, using antibodies generated against two different domains of the protein. In both human and rodent retinae, myosin VIIa was detected in the apical processes of the RPE and in the cilium of rod and cone photoreceptor cells. Immunogold label was most concentrated in the connecting cilium. Here, myosin VIIa appeared to be distributed outside the ring of doublet microtubules near the ciliary plasma membrane. These observations indicate that a major role of myosin VIIa in the retina is in the photoreceptor cilium, perhaps in such a function as trafficking newly synthesized phototransductive membrane or maintaining the diffusion barrier between the inner and outer segments. Our results support the notion that defective ciliary function is the underlying cellular abnormality that leads to cellular degeneration in Usher syndrome.

Blotting, Western↗
PubMed1975

Ultrastructure of the cilia of thymic cysts in "nude" mice.

The ciliary ultrastructure is studied in the ciliated cells of the thymic cysts of the "nude" mouse. The cilium is made up of two segments: the intracellular basal body and the extracellular cilium shaft. The basal body extends in a rootlet and demonstrates three annexes: basal foot, anchoring system and tonofibrillar web. The rootlet, composed of one central and nine peripheral chambers, is closely and constantly associated with smooth endoplasmic reticulum. The classical periodicity of the basal foot can be explained by its internal structure. The anchoring system binds the upper part of the basal body to the cell membrane. The cilium shaft is divided into four segments: implantation base, proximal segment, intermediate segment and tip. The details of particular structures in the implantation base and in the proximal segment are given on transverse and longitudinal sections. In the intermediate part, a peculiar desmosome-like structure, binds some doublets with the ciliary membrane. At the tip level, A tubules end up in an opaque plate and membranes are covered with several intracated cristae.

Animals↗
PubMed1993

The microvilli and hyaline layer of embryonic asteroid epithelial collar cells: a sensory structure to determine the position of locomotory cilia?

Early stage embryos of the starfish Pisaster ochraceus exhibit one cilium per cell which is primarily involved in locomotion. SEM observations have demonstrated two types of microvilli "stage horn"-like and "finger-like" microvilli (CMs), both of which probably serve to anchor and support the hyaline layer (HL). The CMs arise from the cellular membrane a short distance from the base of the ciliary shaft and form a circle around the base of each cilium. This arrangement is found in embryos and larvae as well as in adult tissues of many other marine organisms. TEM observations of material prepared by freeze substitution has demonstrated that the HL unites the circle of CMs and forms two collars. The outer ECM collar is single and attached directly to the CMs, while the inner collar consists of multiple rings of ECM located between the cilium and the CMs. The inner collar elements are not attached to the cilium but are attached to the inner aspects of the CMs by a complex arrangement consisting of a loop of ECM and two short ECM fibers. The arrangement of the ECM of the collars could provide an excellent way to transmit the movements of the cilium to the surrounding microvilli. Although the bases of the CMs always encircle the ciliary shaft, the shafts of the CMs are seen in different positions. This suggests that the CM/ECM collar may be able to change position relative to the cilium. Confocal laser scanning microscopy demonstrates that the CMs contain phalloidin positive material which extends into a phalloidin positive region located in the apex of the cells. The CMs and apical web contain microfilaments which are probably actin and could be involved in movement of the CMs. A movable circle of CMs with their associated ECM could represent a mechanism to sense the position of the cilium and/or to define the direction and extent of the stroke.

Animals↗