Some observations on the fine structure of human granulosa cell tumors

Summary The ultrastructural features of three granulosa cell tumors are presented. The neoplastic non-luteinized granulosa cells are characterized at sub-microscopical level by severely indented nuclei with prominent nucleoli, sparse to moderately developed predominantly granular endoplasmic reticulum, scanty lipids and lysosomes, small mitochondria with lamellar cristae and abundant intracytoplasmic filamentous material. The luteinized cells display a strongly developed tubular agranular endoplasmic reticulum and mitochondria with tubular cristae.These findings are compared with those of previous reports and discussed in relation to the well-known hormonal activity of these tumors.     

Functioning microvillous adenoma of the parathyroid gland containing nuclear pores and annulate lamellae

The cytoplasmic membranes of chief cells in parathyroid adenomas from patients with primary hyperparathyroidism associated with either severe or mild hypercalcemia were examined in an attempt to correlate ultrastructural changes and biochemical findings. In the case involving the highest serum calcium level (17.5 mg/dl), the cytoplasmic membrane exhibited numerous long cytoplasmic processes (microvilli) that extended into wide intercellular spaces. In this respect this tumor, associated with severe hypercalcemia, was different from previously described parathyroid adenomas and from the adenomas of the present study that were associated with mild hypercalcemia (12.4 +/- 0.5 mg/dl); the active chief cells of the latter were characterized by a relatively straight plasmalemma with interdigitations and narrow intercellular spaces. Also of interest in the case involving severe hypercalcemia was the presence of numerous nuclear pores and annulate lamellae as well as an inconspicuous Golgi apparatus. These ultrastructural features would seem to indicate the existence of further morphologic parameters for the evaluation of chief cell activity.     

The fine structure of the body wall of Gyrocotyle urna

Summary The covering layer of Gyrocotyle, which is thought to occupy an intermediate position between the monogeneans and the cestodes, resembles that of the cestodes more than the epidermis of the ectoparasitic monogeneans. It is a cytoplasmic epidermis bearing densely arranged microvilli and is connected to parenchymally situated cell bodies. The microvilli of Gyrocotyle differ from the microtriches of tapeworms in lacking a thickened tip. Vesicles between the microvilli at the free edge of the epidermis are associated with disintegrating striated rod-bodies and are therefore probably secretory rather than concerned with micropinocytosis. The epidermal cell bodies have the characteristics of secretory cells and appear to elaborate the striated rod-bodies which occur throughout the outer epidermis and may consist of condensed mucoprotein. Cells with electron opaque cytoplasm which occur in the neighbourhood of the epidermal cell bodies have been identified as myoblasts. The posterior rosette appears to be specialized for adhesion as gland cells secreting PAS positive material line the ventral rosette surface and the epidermis of this region bears short bifurcate microvilli.

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Zusammenfassung Die Deckschicht von Gyrocotyle, die offenbar eine Zwischen-stellung zwischen der von Monogenen, Trematoden und Cestoden einnimmt, ist der von Cestoden mehr als der Epidermis ektoparasitischer Monogenea ähnlich. Sie stellt eine zytoplasmatische Epidermis dar, die aus dicht stehenden Mikrovilli besteht, und ist verbunden mit einem parenchymatösen Zellkörper. Die Mikrovilli von Gyrocotyle unterscheidet sich von den Mikrotrichen der Bandwürmer darin, daß ihnen eine verdickte Spitze fehlt. Bläschen zwischen der Mikrovilli am freien Rand der Epidermis hängt mit zerfallenden gestreiften stäbchenförmigen Körpern zusammen und sind eher sekretorischer Natur als Ausdruck einer Mikropinozytose. Die epidermalen Zellkörper haben die charakteristischen Eigenschaften von sekretorischen Zellen und scheinen die gestreiften länglichen Körper auszuscheiden, die über die ganze Epidermis verteilt vorkommen und aus einem kondensierten Mukoprotein bestehen. Zellen mit elektronendichtem Zytoplasma, die in der Nachbarschaft der epidermalen Zellkörper auftreten, sind als Myoblasten identifiziert worden. Die hintere Rosette erscheint spezialisiert zum Anheften wie Drüsenzellen; sie sezernieren PAS-positives Material entlang der ventralen Rosetten-Oberfläche. Die Epidermis dieser Region trägt kurze zweigallige Mikrovilli.

     

Abnormal assembly of annulate lamellae and nuclear pore complexes coincides with fertilization arrest at the pronuclear stage of human zygotic development

BACKGROUND: The assembly of nuclear pore complexes (NPC) and their cytoplasmic stacks, annulate lamellae (AL), promote normal nucleocytoplasmic trafficking and accompany pronuclear development within the mammalian zygote. Previous studies showed that a percentage of human oocytes fertilized in vitro failed to develop normal pronuclei and cleave within 40-48 h post insemination. We hypothesized that an aberrant recruitment of NPC proteins, nucleoporins and/or NPC preassembled into AL, might accompany human fertilization arrest. METHODS AND RESULTS: We explored NPC and AL assembly in unfertilized human oocytes, and fertilized and arrested zygotes by immunofluorescence with an NPC- and AL-specific antibody, mAb 414, and by transmission electron microscopy. Major NPC or AL assembly was not observed in the unfertilized human oocytes. Once fertilization took place, the formation of AL was observed throughout the cytoplasm and near the developing pronuclei with NPC. On the contrary, NPC assembly was disrupted in the arrested zygotes, whereas AL were clustered into large sheaths. This was accompanied by the lack of NPC incorporation into the nuclear envelopes. CONCLUSIONS: We conclude that the aberrant assembly of NPC and AL coincides with early developmental failure in humans.     

Some observations on the fine structure of the epidermal-dermal junction in the skin of the frog tadpole,Rana rugosa

Special lamellated bodies, 400 to 700 Å in diameter, are observed in the adepidermal space at the epidermal-dermal junction of the skin of the frog tadpole, Rana rugosa. Each stained lamella is about 20 Å thick and separated from adjacent lamellae by spacings of 20 to 30 Å. The lamellated bodies are demonstrated in specimens prepared with phosphotungstic acid (PTA)-containing fixatives, but are not revealed in specimens fixed with ordinary aldehyde fixatives which lack PTA. They are sometimes observed within the cytoplasm of basal epidermal cells, suggesting their epidermal origin. Far less frequently, comparable structures are present outside the sarcolemma of skeletal muscle fibers. Three kinds of anchoring structures are observed at the epidermal-dermal junction: anchoring filaments, anchoring fibrils, and anchoring fibers. The anchoring filaments are observed in the adepidermal space connecting hemidesmosomes to the basal lamina. They are 200 to 230 Å in diameter and have no banding pattern. Anchoring fibrils, 210 to 250 Å thick and unbanded, are present in the upper one-third of the collagenous lamellae. Fibrils do not have a banding pattern. Direct continuity between anchoring fibrils and anchoring filaments is suggested. Anchoring fibers, about 170 mμ, thick, occur less frequently. They are composed of laterally aggregated finer fibrils which show no clear bandings. Their distal ends join with the basal lamina and they extend proximally deep into the collagenous lamellae.     

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

Background: It is known that melanocytes exist in almost all parts of the inner ear, such as the cochlear duct, stria vascularis, Reissner's membrane, modiolus, vestibular organs in the region surrounding the cristae and maculae, semicircular canals, and pars rugosa of the endolymphatic sac. But there have been few studies using human materials, because of the difficulty of obtaining materials. We attempted to investigate the detailed ultrastructure of melanocytes in the vestibular organs of human inner ear. Methods: Eight surgical specimens obtained from patients with vestibular schwannoma were studied by light microscopy and electron microscopy. Results: Melanocytes were found in the subepithelial layer of the dark cell area. Melanocytes had round or spindle-shaped nuclei and clear cytoplasm with brown pigment granules. Besides melanocytes, there were melanophages, fibroblasts, and small blood vessels. Through electron microscopy we found melanocytes with round-shaped melanosomes in various stages of pigmentation, well-developed Golgi apparatus and endoplasmic reticulum in the cytoplasm, and many cytoplasmic processes. Gap junctions were occasionally found between the cytoplasmic processes. And there were pinocytotic vesicles just under the limiting membrane of melanocytes, and intermediate filaments were abundant in the cytoplasm. Isolated cilia of melanocytes, annulate lamellae, and fusiform banded structures in the connective tissue area around melanocytes were found. Conclusions: Melanocytes in human vestibular organs actively synthesize melanosomes. Frequent findings of isoalted cilia and fusiform banded structures and the incidental existence of annulate lamellae may be an indicator of this metabolically activated state of melanocytes. Moreover, monitoring environmental changes by isolated cilia, melanocytes in the human inner ear could act not only as one cell but also as a group to achieve their physiological functions by means of information transmission through gap junctions. © 1994 Wiley-Liss, Inc.