Light- and electron-microscopic study of the endolymphatic sac of the tree frog, Hyla arborea japonica

The endolymphatic sac of the tree frog and its crystals were observed by light- and electron microscopy. Scanning electron microscopy revealed that the crystals have a faceted body and two pointed ends. Light- and transmission electron microscopy revealed that the endolymphatic sac is composed of many small chambers. In their lumina, numerous "ghosts" of crystals that resulted from decalcifications were observed. The ghosts were demarcated by a linear dense material or embedded in a flocculent substance. The epithelium of the endolymphatic sac is simple squamous or cuboidal and peculiar cytoplasmic granules are found in most cells. The granules are surrounded by a limiting membrane and have varying electron density. Some granules contain a core and/or tubular structures. Vacuoles containing large ghosts are also found in the epithelial cells. These ghosts were quite similar to those in the lumen and sometimes coexist with cell debris. The fine structure of the endolymphatic sac and its crystals is discussed.

Incorporation of strontium into the calcium carbonate crystals of the endolymphatic sac in the tree frog (Hyla arborea japonica)

Tree frogs were loaded with strontium chloride (SrCl2). The incorporation of strontium metal into the calcium carbonate (CaCO3) crystals located both in the inner ear and in the endolymphatic sac was studied by x-ray microanalysis (XMA) and scanning electron microscopy (SEM). In the inner ear, strontium was not recognized except for traces in a few crystals. When observed by SEM, these crystals had a faceted body and two pointed ends with rather smooth surfaces. However, in the endolymphatic sac, which greatly expands into the spinal canal, strontium was clearly present at every surface of all crystals. Careful examinations by point and line XMA revealed that strontium x-ray counts were highest at the pointed ends and decreased sharply and then gradually toward the equator of the crystals. SEM observations revealed that the crystals in the endolymphatic sac always had rough and irregular surfaces regardless of their shapes and sizes. Calcium was always found in crystals of both organs. Except for calcium and strontium, other elements including sodium and heavier elements were negligible in XMA. These findings suggest that strontium is incorporated into the crystals only in the endolymphatic sac, and the rough-surfaced covering of these crystals reflects newly deposited strontium salt. It seems to indicate that these crystals grow predominantly by accretion.

Liddle's syndrome, an uncommon form of hyporeninemic hypoaldosteronism: functional and histopathological studies

Liddle's syndrome was diagnosed in a 72-year-old man who presented clinically with hypertension and muscle weakness. This disorder has been characterized by hyporeninemic hypoaldosteronism, hypertension, hypokalemia and enhanced erythrocyte sodium influx. Administration of spironolactone failed to correct the hypertension and electrolyte abnormality, which subsequently improved with triamterene therapy and a low salt diet. However, suppression of the renin-angiotensin-aldosterone system remained unchanged after this treatment. In addition, an atrophic juxtaglomerular apparatus and hypertensive lesions in the arterioles were confirmed by kidney biopsy after triamterene therapy. Therefore, a process of intrinsic hyperactive distal sodium reabsorption, probably affected by aldosterone-independent sodium transport into erythrocytes, appears to be important in the pathogenesis of this syndrome. Triamterene therapy, which usually is performed in patients with this disease, might not be the ultimate therapy in the future even if electrolyte abnormalities were to be improved temporarily.

Electronmicroscopic observation of the human facial nerve

The facial nerves of Bell's palsy, Ramsay-Hunt's syndrome and traumatic facial palsy patients were studied using a transmission electron microscope. Changes were a proliferation of the collagen fibres, the degeneration of the Schwann cell, and a loosened or deteriorated myelin sheath. These changes differ considerably between individuals. Changes also vary in one subject. The cause and severity of the lesion, the duration of the palsy and the location of biopsy are possibly responsible for this phenomenon.

The fine structure of atypical ciliated cells in the human gastric epithelium

Gastric mucosa obtained from the body and pyloric portions of the human stomach were observed by light and transmission electron microscopy. Ciliated cells were found in two of 18 subjects examined, one patient with gastric ulcer and the other one with gastric adenocarcinoma. The ciliated cells were found in epithelia at sites away from the main lesions. The tissues containing ciliated cells showed intestinal metaplasia combined with mild chronic gastritis in both cases. The epithelial layer facing the gastric lumen was composed of columnar cells with numerous uniform microvilli and goblet cells. This epithelium extended to the superficial parts of the tubules surrounded by the lamina propria. The deeper portions of the tubules were composed of mucous secretory, endocrine, and rarely ciliated cells. These ciliated cells were provided with numerous cilia the numbers of which varied considerably from cell to cell. This was in contrast to the primary cilium which is usually single. The central part of the apical cell membrane was sometimes concave in the area from where cilia tended to arise. It was also observed that numerous basal bodies as well as mucus-like granules were contained in the same cell. The axonemal pattern was different from that of ordinary cilia and showed 9 + 0 and 8 + 1 patterns. In longitudinal sections it was found that one peripheral doublet was displaced to the center of the axoneme as it left the basal body.

Electron-microscopic study of the vestibular dark cells in the crista ampullaris of the guinea pig

The ultrastructure of the vestibular dark cells in the crista ampullaris of the guinea pig was observed using both transmission and scanning electron microscopy. The dark cells had numerous vacuoles of varying size and electron density, and also characteristic well-developed basal infoldings. These findings strongly suggest that the dark cells play an important role in fluid transport. Unique meshwork structures were observed on the luminal surface of the dark cells. Otoconia showing varying degree of degeneration were occasionally recognized on and near these structures. Electron microscopy revealed that the meshwork was comprised of cytoplasmic processes in a reticular arrangement. They seem to be engaged in the metabolism of otoconia, and perhaps also in fluid transport.

Fine structural and cytochemical aspects of granuloma formation derived from Kupffer cells in mice injected with latex particles

The fate of Kupffer cells in mice for 3 days following injection with polystyrene latex particles (0.2 and 2.0 micron in diameter) was studied by electron microscopy. Kupffer cells took up the latex particles by pinocytosis as well as by phagocytosis. The particles ingested were in contact or fused with lysosomes in the cell. Two days after the final injection, most Kupffer cells were already stuffed with the particles. Within one month, cell clumps or cell aggregates, which could be called granuloma, were formed in the liver connective tissue space, i.e., Disse spaces, interlobular connective tissue spaces and subperitoneal connective tissue spaces. They were mostly composed of cells laden with numerous latex particles. The large granulomas were 80-120 micron in diameter. In each granuloma, endogenous peroxidase was localized in the cisternae of the nuclear envelope and of the rough endoplasmic reticulum of most cells, and in the cytoplasmic granules of some other cells. The former is known to be a Kupffer cell, and the latter, a monocyte. The granuloma further contained a few intermediate cells, showing peroxidase activity in the cisternae of the nuclear envelope and of the rough endoplasmic reticulum, and also in the cytoplasmic granules, phagocytic cells without peroxidase activity, granulocytes, and plasma cells. Hepatic sinusoidal endothelial cells, attenuated in shape, also took up latex particles of a 0.2 micron diameter and rarely with a 2.0 micron diameter in their cytoplasm. Some Kupffer cells in the granuloma filled with numerous latex particles were labeled with 3H-thymidine (2.5 mCi in total dose) after subcutaneous injection ten times for 80 hr. In the animals 8 months after the injection of the latex particles, numerous large granulomas were distributed throughout the liver in the interlobular or subperitoneal connective tissue space. The formation of the granuloma of Kupffer cells is considered to play a great role in the disposing of foreign materials from the functional liver parenchymatous tissue.

Electron microscopic studies on multinucleate foreign body giant cells derived from Kupffer cells in mice given Indian ink intravenously

Changes in Kupffer cells in mice given intravenous Indian ink were studied with the electron microscope. Kupffer cells as well as hepatic sinusoidal endothelial cells take up Indian ink particles by pinocytosis. In addition, a few Ito cells and hepatocytes ingest a small number of particles. The carbon particles are stored in cytoplasmic vacuoles in all these cell types. Aggregates of Kupffer cells containing many vacuoles stuffed with carbon particles are seen in the sinusoidal lumen, Disse space and interlobular connective tissue space 3 and 4 days after injection with Indian ink. One month after the injection, large clumps of aggregated Kupffer cells containing numerous carbon-filled vacuoles are distributed in the Disse space and other connective tissue spaces. The Kupffer cells in these clumps are in close contact and are partly fused with one another. After 3, 4 and 6 months, large multinucleate foreign body giant cells with numerous large vacuoles containing densely-packed ink particles are seen throughout the liver tissue. They are considered to be formed by fusion of Kupffer cells. Some endothelial cells also store ink particles in cytoplasmic vacuoles for as long as 6 months after injection.

Fine structural aspects of the development and aging of the tracheal epithelium of mice

The fine structure of the mouse tracheal epithelium from the fetal period to the stage of old age was examined with electron and light microscopes. The tracheal epithelium of the adult mouse is ciliated and single columnar in shape, consisting of three kinds of cells: ciliated, non-ciliated and basal. Neither goblet nor brush cells were found. The earliest signs of the cytodifferentiation of ciliated and non-ciliated cells appear at 15 and 17 days of gestation respectively. The secretory granules in non-ciliated cells appear at 17 days of gestation, and increase in number from 18 days of gestation (one day before birth) to 1 day after birth and decrease in number rapidly, while elements of smooth endoplasmic reticulum appear in this cell. Non-ciliated cells constitute the major component of the tracheal epithelium in the adult mouse. They have two kinds of granules: one a secretory granule surrounded by a single limiting membrane and released by exocytosis, and the other surrounded by double limiting membranes and considered to be derived from mitochondria. With the advance of age, some parts of the epithelium invaginate into the lamina propria without any noticeable changes in either the epithelial cells or the basal lamina. These invaginations, which the present authors named "cyst-like structures," are found in all mice over four months of age examined, and increase in number and size with age. They seem to be physiological structures and are distributed in all parts of the tracheal epithelium from the first tracheal ring to the tracheal bifurcation. They contain concentric circular materials with entangled filaments (15-20 nm in diameter) and/or destructed cell debris mainly derived from granular leucocytes.