Ultrastructure of melanocytes in the dark cell area of human vestibular organs: Functional implications of gap junctions, isolated cilia, and annulate lamellae

Masuda, Masataka; Yamazaki, Kazuto; Kanzaki, Jin; Hosoda, Yasuhiro

doi:10.1002/ar.1092400406

Cited by 22 publications

(40 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most authors believe that AL are associated wlth a high level of cellular metabolism or have a role in cell growth and differentiation (e.g. Wang et al 1992, Masuda et al 1994, Watanabe et al 1995. The hypotheses as to the significance of AL have so far not been substantiated, so we cannot assess the functional implications of this organelle in the present organism.…”

Section: Discussionmentioning

confidence: 92%

An enigmatic and possibly parasitic organism in the tissues of embryonated eggs of Baltic cod Gadus morhua

Bloch¹,

Bh²,

Pv³

1997

Dis. Aquat. Org.

View full text Add to dashboard Cite

Tissues and interstitial compartments of cod Gadus morhua embryos which were infected by an endoparasite in the yolk were investigated by transmission electron microscopy. Small enigmatic organisms, presumed to be of parasitic nature, were observed in the embryonic cells and tissues. The organisms lacked a cell wall. In addit~on to intermediate stages, at least 3 distinct stages of the organism were observed. The organisms were located both extra-and intracellularly, in the latter case often surrounded by vacuoles. The stages of the organism differed in their chromatin configurations. One stage contained groups of finely and coarsely flocculated chromatin without a nucleolemma. Juxtapositioned chromatin groups were separated by annulate lamellae. Another stage had one or more nucleus-like elements, each surrounded by a dilated cisterna with a few pores. The cisternae of such adjoining elements formed annulate lamellae, which could break to form a common vacuole. Vacuoles might then fuse with the outer membrane of the organism thereby freeing the nucleus-like elements as daughter elements. Such daughter elements were observed extra-and intracellularly in embryonic cod. The third stage contained several nucleated daughter cells, and lacked annulate lamellae. The identity of the organism is unknown.

show abstract

Section: Discussionmentioning

confidence: 92%

An enigmatic and possibly parasitic organism in the tissues of embryonated eggs of Baltic cod Gadus morhua

Bloch¹,

Bh²,

Pv³

1997

Dis. Aquat. Org.

View full text Add to dashboard Cite

show abstract

“…In the mouse, maintenance of the endocochlear potential depends on expression of the potassium channel Kcnj10 in intermediate cells (Marcus et al, 2002;Wangemann et al, 2004). Melanocytes also populate vestibular regions and the endolymphatic apparatus in the mammalian ear (Masuda et al, 1994;Escobar et al, 1995;Peters et al, 1995;Stanchina et al, 2006), but their role here is less clear; for example, mutations in Kcnj10 have no effect on vestibular endolymph (Marcus et al, 2002). Analysis of the inner ear phenotype in murine models of WS and other auditory-pigmentary disorders has focused on the presence of intermediate cells in the stria vascularis; deafness is usually attributed to the loss of intermediate cells in this tissue, leading to a reduction or collapse of endolymph volume, a loss of the endocochlear potential and subsequent hair cell degeneration (Tachibana et al, 1992;Cable et al, 1994;Matsushima et al, 2002;Stanchina et al, 2006) (reviewed by Tachibana, 1999;Tachibana et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

A zebrafish model for Waardenburg syndrome type IV reveals diverse roles for Sox10 in the otic vesicle

Dutton

Abbas

Spencer

et al. 2009

Disease Models &Amp; Mechanisms

View full text Add to dashboard Cite

SUMMARYIn humans, mutations in the SOX10 gene are a cause of the auditory-pigmentary disorder Waardenburg syndrome type IV (WS4) and related variants. SOX10 encodes an Sry-related HMG box protein essential for the development of the neural crest; deafness in WS4 and other Waardenburg syndromes is usually attributed to loss of neural-crest-derived melanocytes in the stria vascularis of the cochlea. However, SOX10 is strongly expressed in the developing otic vesicle and so direct roles for SOX10 in the otic epithelium might also be important. Here, we examine the otic phenotype of zebrafish sox10 mutants, a model for WS4. As a cochlea is not present in the fish ear, the severe otic phenotype in these mutants cannot be attributed to effects on this tissue. In zebrafish sox10 mutants, we see abnormalities in all otic placodal derivatives. Gene expression studies indicate deregulated expression of several otic genes, including fgf8, in sox10 mutants. Using a combination of mutant and morphant data, we show that the three sox genes belonging to group E (sox9a, sox9b and sox10) provide a link between otic induction pathways and subsequent otic patterning: they act redundantly to maintain sox10 expression throughout otic tissue and to restrict fgf8 expression to anterior macula regions. Single-cell labelling experiments indicate a small and transient neural crest contribution to the zebrafish ear during normal development, but this is unlikely to account for the strong defects seen in the sox10 mutant. We discuss the implication that the deafness in WS4 patients with SOX10 mutations might reflect a haploinsufficiency for SOX10 in the otic epithelium, resulting in patterning and functional abnormalities in the inner ear.

show abstract

“…1a). Melanin pigment granules in the intraepithelial layer might be present in the cytoplasm of dark cells or intraepithelial melanocytes (Masuda et al, 1994(Masuda et al, , 1995a. In the subepithelial layer, melanocytes had spindle-shaped cell bodies with clear cytoplasm containing melanin pigment granules and well-developed cell processes.…”

Section: Light Microscopic Observationmentioning

confidence: 99%

“…3a, 4a,c, 5a). Incomplete layers of external lamina could be seen around the cell processes of subepithelial melanocytes and their cell bodies (Masuda et al, 1994(Masuda et al, , 1995a(Masuda et al, ,b, 1996.…”

Section: Tem Examinationmentioning

confidence: 99%

“…The dark cell area, which consists of epithelial dark cells, melanocytes, melanophages, subepithelial small blood vessels, and other cellular and stromal components, could be a significant functional site for the vestibular organs of the human inner ear (Masuda et al, 1994(Masuda et al, , 1995a(Masuda et al, , 1996. Small blood vessels like capillaries could be a site for the active transmission of various materials and transmigration of cellular components from the blood to the tissues (Cotran, 1994).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Immunohistochemical and ultrastructural investigation of the human vestibular dark cell area: Roles of subepithelial capillaries and T lymphocyte‐melanophage interaction in an immune surveillance system

et al. 1997

Self Cite

View full text Add to dashboard Cite

Background: The aim of the present study was to morphologically characterize the structure of the subepithelial blood vessels in the dark cell area of the human vestibular organs, and to determine whether immunocompetent cells such as macrophages and lymphocytes could be found around these small blood vessels.Materials and Methods: All 31 surgical specimens (semicircular canals and utricles) were obtained from patients with vestibular schwannoma. Formalin fixed specimens were stained with hematoxylin and eosin (H&E), and with antibodies to von Willebrand Factor (vWF), leukocyte common antigen (LCA), and UCHL-1, and were examined with light microscope. Specimens fixed with glutaraldehyde were examined with a transmission electron microscope (TEM).Observations: Subepithelial blood vessels stained positive for vWF. By TEM observation, these blood vessels were observed to be capillaries that consisted of non-fenestrated endothelium, occasional pericytes, and a basement membrane. They were usually accompanied by melanophages with a number of secondary lysosomes containing phagocytosed degraded melanosomes and lipid droplets. Moreover, melanocytes and their cell processes directly surrounded these subepithelial capillaries. The fact that cells which were positively stained with LCA and UCHL-1 were present both in the intra-and subepithelial layer of the specimens, and that by TEM the intra-and subepithelial mononuclear cells with a lymphoid appearance had clustered dense bodies in their cytoplasm, suggested that they were a population of T lymphocytes.Conclusions: Results suggested the possibility of a T lymphocytemelanophage (macrophage) interaction, both originating from and harbored around subepithelial capillaries, which suggests the presence of an immune surveillance system in the human vestibular organs. Anat.

show abstract

Ultrastructure of melanocytes in the dark cell area of human vestibular organs: Functional implications of gap junctions, isolated cilia, and annulate lamellae

Cited by 22 publications

References 33 publications

An enigmatic and possibly parasitic organism in the tissues of embryonated eggs of Baltic cod Gadus morhua

An enigmatic and possibly parasitic organism in the tissues of embryonated eggs of Baltic cod Gadus morhua

A zebrafish model for Waardenburg syndrome type IV reveals diverse roles for Sox10 in the otic vesicle

Immunohistochemical and ultrastructural investigation of the human vestibular dark cell area: Roles of subepithelial capillaries and T lymphocyte‐melanophage interaction in an immune surveillance system

Contact Info

Product

Resources

About