Obliteration of the Ductus Reuniens

Kimura, Robert S.; Schuknecht, Harold F.; Ota, Carol Y.; Jones, Diane D.

doi:10.3109/00016488009127141

Cited by 89 publications

(36 citation statements)

References 25 publications

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“…Previous studies have suggested that the ES promotes homeostasis in the membranous labyrinth by the regulation of endolymph volume and the elimination of endolymph debris (Thalmann and Thalmann, 1999). Furthermore, it has been proposed that endolymph is secreted from both the stria vascularis and the vestibular dark cell area, and is then reabsorbed in the ES (the longitudinal flow theory) (Lundquist, 1965;Kimura et al, 1980;Manni and Kuijpers, 1987). Manni and Kuijpers (1987) demonstrated the existence of longitudinal flow under physiological conditions; i.e., the macromolecules are secreted into the endolymph, subsequently passed into the cupula and otolithic membrane, which has the same basic structure as the tectorial membrane, and after being released the macromolecules and/or their derivatives gradually move toward the ES.…”

Section: Discussionmentioning

confidence: 99%

Soluble Megalin Is Accumulated in the Lumen of the Rat Endolymphatic Sac

Ishida

Hatae

Nishi

et al. 2006

Cell Struct. Funct.

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ABSTRACT. The endolymphatic sac (ES) is believed to play an important role in maintaining homeostasis in the inner ear by the absorption and endocytosis of endolymph. Megalin is a 600-kDa multiligand endocytic receptor expressed in certain types of absorptive epithelia including kidney proximal tubules. We analyzed the immunoreactivity for megalin in rat ES by immunofluorescence, immunogold electron microscopy, and immunoblotting. With immunostaining, the luminal substances of the ES were strongly stained for megalin. Megalin was also localized in luminal macrophage-like cells and both types of epithelial cell (mitochondria-rich cells and ribosomerich cells). In these cells, the megalin was localized in the lumen of endosomes, but was not membrane associated. This localization pattern indicates that the megalin in these cells is not a membrane receptor, but merely one of the constituents that are endocytosed from the lumen of the ES. Immunoblotting indicated that the megalin in the ES is a 210-kDa molecule lacking a cytoplasmic domain. This suggests that the megalin in the ES may be a soluble form, different from the 600-kDa membrane-bound receptor expressed in kidneys. Taken together, it is likely that the megalin in the ES lumen is a soluble component and may be endocytosed by the ES epithelial cells. Furthermore, we found that the tectorial membrane, an acellular structure in the cochlea, gave a strong megalin immunoreaction. Since the cochlea is connected to the ES, the megalin may be transported alone or with the components of the tectorial membrane from the cochlea to the ES lumen through longitudinal flow.

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Section: Discussionmentioning

confidence: 99%

Soluble Megalin Is Accumulated in the Lumen of the Rat Endolymphatic Sac

Ishida

Hatae

Nishi

et al. 2006

Cell Struct. Funct.

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“…Endolymphatic hydrops, however, can occur in adults [12] and children [9] without clinical Ménière's disease, but it is still not known whether a slowly increasing volume of endolymph will result in spontaneous ruptures, especially because the endolymph/perilymph system is a low-pressure system [13]. Furthermore it is not clear, whether or not the guinea pig model for endolymphatic hydrops (ablation of the endolymphatic sac [4] or ductus reuniens [3]) is relevant to the human labyrinth in the pathophysiology of Ménière's disease.…”

Section: Discussionmentioning

confidence: 99%

“…This has generated the concept that increasing endolymphatic pressure causes ruptures with subsequent mixing of perilymph and endolymph, triggering the sudden onset of vertigo in Ménière's disease [8]. The existence of membrane ruptures, however, has been doubted because no reproducible ruptures after induced endolymphatic hydrops occurred in the experimental animals [3,4].…”

Section: Introductionmentioning

confidence: 99%

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Ante mortem Ruptures of the Endolymphatic Membranes in Children: Real Finding or Artifact?

Bachor

Karmody

2002

ORL

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We undertook this study to determine whether or not ante mortem ruptures of the endolymphatic membranes occurred naturally in the infantile labyrinth, what were the most frequent locations and to assess the statistical correlation of an earlier finding of bulging of Reissner’s membrane in pediatric temporal bones. We examined 128 temporal bones from 80 children between the ages of newborn to 12 years with an average age of 15.4 months. All temporal bones were prepared by the celloidin technique and studied by light microscopy. The endolymphatic membranes of the cochlear duct, saccule, utricle and semicircular ducts were examined for ruptures. A rupture of the saccule and utricle was considered to be an ante mortem event if its edges were rolled and bound with fine adhesions and could be identified in adjacent sections. Ante mortem ruptures were seen in 11.1% of the specimens and occurred in 2.4% in Reissner’s membrane, in 6.3% in the saccular membrane and in 2.4% in the utricular membrane. In these specimens, the histopathological changes included atrophy of the stria vascularis and collapse of the organ of Corti, which provided further evidence of an ante mortem event. Infants with extralabyrinthine congenital anomalies or children who were treated with chemotherapy were more likely to develop ruptures of the endolymphatic membranes if they also received aminoglycosides.

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“…Obliteration of the ductus reuniens is considered by some authors to be an etiological factor for cochlear EH [15,16]. The size of the ductus reuniens was classified into three diameters -wide, narrow and collapsed ( fig.…”

Section: Methodsmentioning

confidence: 99%

Endolymphatic Hydrops in Children

Bachor

Karmody

1995

ORL

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Apart from clinical observations of Ménière’s disease in children, there have only been a few histological descriptions of endolymphatic hydrops (EH) as an incidental finding in children. In this paper we report on the incidence of EH in temporal bones of children. One hundred eighteen temporal bones from 70 infants between newborn and 10 years (average age 12.9 months) were analyzed by light microscopy for EH of the cochlear duct, which was defined as a bulging of Reissner’s membrane into the scala vestibuli in more than one turn of the cochlea. All endolymph spaces were carefully examined for factors such as an obliterated ductus reuniens which may have contributed to the development of EH. In 64 (54.2%) of the 118 temporal bones, a bulging of Reissner’s membrane in the cochlear duct was found. In 65.6%, the bulging was confined to the apical turn and since the significance of isolated apical hydrops is controversial, we elected not to consider this group as having hydrops. Twenty (16.9%) bones met our criteria for a diagnosis of EH. Compared to the high incidence of bulging in the cochlear duct, fewer saccules and utricles were dilated. In approximately half of the temporal bones (49.2%), the ductus reuniens was collapsed. The ductus reuniens seems to be closed in its normal position and might open when pressure occurs due to an increasing volume of endolymph. If there is a permanent closure, EH may result. Our investigation does not indicate that EH is associated with a specific disease; however, where there were congenital anomalies the incidence of EH was higher. The endolymph system seems to be sensitive to external disturbances, and EH is possibly related to many kinds of metabolic disorders of early infancy.

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Obliteration of the Ductus Reuniens

Cited by 89 publications

References 25 publications

Soluble Megalin Is Accumulated in the Lumen of the Rat Endolymphatic Sac

Soluble Megalin Is Accumulated in the Lumen of the Rat Endolymphatic Sac

Ante mortem Ruptures of the Endolymphatic Membranes in Children: Real Finding or Artifact?

Endolymphatic Hydrops in Children

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