Pyoyun Park

Viral Behavior of Paracrystalline Inclusions in Osteoclasts of Paget's Disease of Bone

Fresh tissues from six patients with Pagets disease of bone were examined ultrastructurally to investigate whether the characteristic paracrystalline inclusions in pagetic osteoclasts revealed viral behavior. These inclusions appeared as microfilamentous aggregates in both nuclei and cytoplasm of the osteoclasts in all six cases. The filamentous elements of the inclusions with a diameter of 11-15 nm showed tubular structures with a central electron-lucent zone measuring 5-7 nm in diameter. Viral budding-like structures containing these inclusions were found at the peripheral cytoplasm or cell processes in the ruffled border of some pagetic osteoclasts in two cases. The inclusions in the budding-like structures were often arrayed in a parallel fashion on the cytoplasmic side of the cell membranes of extruded cytoplasm or cell processes. Virion-like particles were also found in the extracellular spaces of the ruffled border. Marked nuclear degeneration was often seen in pagetic osteoclasts of three cases, although other nuclei in the same osteoclasts appeared normal. The degenerated nuclei showed nuclear ring formation where destroyed nuclear membranes were seen and disappearance of nuclear matrices was noted. Since the modifications were always associated with the accumulation of abundant inclusions, they were probably caused by the inclusions. These findings suggested that the inclusions showed viral behavior in pagetic osteoclasts, and that the nuclear modifications were caused by virus infection.

Ultrastructural study of long spacing collagen fibres and basal lamina in malignant schwannoma

It was found by electron microscopy that extracellular darkly stained materials (DSM) observed abundantly in a case of malignant schwannoma were closely related to both basal lamina and fibrous long spacing collagen (FLS). The FLS were characterized by the cross bands with a 95 nm periodicity, and longitudinally aligned filaments, 9 nm in diameter, while DSM consisted of amorphous material, and 9 nm filaments. The filaments in DSM and FLS were similar in diameter and morphology to reticular fibres in basal laminae. The DSM were continuous with both dark bands of FLS and basal laminae. These results indicate that basal laminae may be the common origin of DSM and FLS. Ultrastructural features of longitudinal, transverse and oblique sections were described.

Ultrastructural study of a clear cell sarcoma suggesting schwannian differentiation.

A clear cell sarcoma that developed on the left back of a 19-year-old Japanese female was studied ultrastructurally. The findings included basal laminae, desmosomelike junctions, cytoplasmic interdigitations, lamellar bodies, and immature melanosomes. These findings suggest schwannian differentiation of this tumor, since they are not usual features of malignant melanoma except for melanosomes. Therefore this tumor seems to be more akin to malignant schwannoma than to malignant melanoma.

Morphogenesis and origin of fibrous long-spacing collagen fibers in collagenase-treated mouse skin tissues

Morphogenesis and origin of fibrous long-spacing collagen (FLS) fibers in newborn mouse skin tissues treated with collagenase were examined using ultrastructural observation, morphometry, histochemical methods, and immunoelectron microscopy. The enzyme caused both the partial destruction of basal laminae and the formation of abundant FLS fibers in the dermal matrix. The fibers were usually distributed in the vicinity of basal laminae in the capillaries or basal layer cells. The fibers were characterized by the cross-striated dark bands with about 91 nm periodicity and longitudinally aligned filaments with a diameter of about 6.5 nm. The dark bands of FLS fibers were often continuous with the basal laminae. Histochemical results showed that the dark bands contained the similar mucopolysaccharides which were involved in the basal laminae. Immunoelectron microscopic results showed that laminin was present in the dark bands as well as in the basal laminae, and that type VI collagen was located in the filaments of FLS fibers. These results suggest that the dark bands are formed by products similar to basal laminae and that the products were precipitated on type VI collagen-contained filaments with periodic intervals of about 91 nm. Morphometric examination revealed that there was no differences in ultrastructure between FLS fibers of a collagenase-treated mouse and those of a human neural tumor.

Case report 382

This 16-year-old Japanese boy noticed pain in his left ankle during exercise in July 1983. A diffuse swelling appeared on the medial aspect of his left ankle; for this reason he visited his physician and was treated as having a simple sprain. In November 1983, he was kicked on the medial aspect of his left ankle and visited another physician. A simple contusion was diagnosed and he was given conservative treatment (e.g. casting, diathermy), but the swelling did not disappear. He than visited the Maeda Hospital on February 29, 1984, where radiological studies showed the osteolytic lesion(s) demonstrated in Figs. 1 and 2. Hypervascularity on angiography at the site of the lesion was demonstrated and intensive uptake on bone scans

Ultrastructural Study of a Clear Cell Chondrosarcoma

A lesion in the left humeral head of a 15-year-old Japanese boy was light-microscopically diagnosed as clear cell chondrosarcoma. Fresh tissues from the lesion were studied ultrastructurally. In most tumor cells, that is, clear cells, paucity of organelles, sparse free ribosomes, and low protein content in cytosol were most striking. Tumor cells had many microvilli characteristic of cartilage cells. Among scanty organelles, vesicles or cisternae of dilated rough endoplasmic reticulum were rather conspicuous, and well-developed Golgi complexes were sparse. Intercellular matrix was scanty. These results suggest that intercellular matrix substance may be synthesized substantially by rough endoplasmic reticulum, whereas the synthesized substance perhaps cannot be transported smoothly into extracellular spaces because of scanty well-developed Golgi complexes.

Alkaline Bismuth Solution as an En Bloc Stain for Formaldehyde-Glutaraldehyde Potassium Permanganate Fixed Fungal Spores

An alkaline solution of bismuth subnitrate reacted well with the cell membranes and cell walls of formaldehyde-glutaraldehyde potassium permanganate fixed Alternaria spores, demonstrating them with greater contrast than in sections stained with uranyl acetate and lead citrate. Optimal fine structure of fungal spores was obtained by en bloc staining with alkaline bismuth solution after aldehyde and permanganate fixation. The contrast of the cell organelles and cell walls was high enough in sections cut after the alkaline bismuth en bloc stain for direct ultrastructural observation. Our results indicate that the alkaline bismuth stain is useful either as an en bloc or section stain for aldehyde and permanganate fixed fungal spores.

Spinal cord compression by epidural metastases: fibrosarcoma experiments in rats

Morphologic changes were studied in 43 rats that were paralyzed by an epidural fibrosarcoma inoculated through the spinous process. By this technique, of 29 rats examined radiographically, the tumor destroyed vertebral bone in 22. Changes of the cord in the early stage of paralysis were specially analyzed by Marchis stain and microangiograms. In compromised cord segments in the early stage, extravasation of contrast medium was observed in the gray matter and the dorsal funiculus; and in the dorsal funiculus just proximal or distal to the compressed portion, hemorrhagic areas were present. Ascending degenerated fibers in the dorsal funiculus, which were derived from the degenerated posterior nerve root or the degeneration of the dorsal funiculus in the compressed segments, were characteristically detected in rats in the early stages. In the advanced stages a transverse cord lesion was observed at the involved level. Based on the present analyses, to prevent more advanced damage to the spinal cord, the tumor should be removed at an early stage that clinically coincides with the period when radicular signs appear.

Primary Effect of a Host-Selective Toxin From Magnaporthe Grisea to Mitochondria of Rice Leaves

The effects of the toxin produced by the rice blast fungus Magnaporthe grisea on host (rice and barley) and non-host (finger millet) plants were examined by ultrastructural observation and morphometric measurement. The first toxin-induced changes in rice and barley plants were the loss of the mitochondrial matrix and the disruption of mitochondrial cristae. These modifications in mitochondria were observed 1 hr after toxin exposure and the frequency of modified mitochondria did not increase with time after toxin treatment. Morphological and ultrastructural changes were not observed in other organelles. Toxin effects were observed in epidermal, mesophyll and phloem cells of barley and rice but not in leaves of the non-host plant, finger millet. Further, mitochondrial modifications were observed in epidermal cells of rice cv. Asahi 12 hr after inoculation of M. grisea spores. These results indicated that mitochondrial modification induced by the toxin was a host-specific phenomenon and possibly an essential event for M. grisea to establish basic compatibility with host plants at the species level.

Smooth Tubular Aggregates Associated with Plasmalemmal Invagination in Alveolar Soft Part Sarcoma

The ultrastructure of four alveolar soft part sarcomas was examined to search for ultrastructural signs of myogenic or neural origin. A new ultrastructural structure, an unusual tubular structure, was found in two of four cases. The structure appeared as a large, smooth, tubular aggregate in the cytoplasm of some tumor cells but did not show a honeycomb arrangement of tubules. The aggregate was composed of long, serpentine, branching, smooth, irregularly arranged tubules without ribosomes that ran in various directions. The aggregates intermingled with small amounts of cytoplasmic organelles. Because the aggregated tubules were at times continuous with cell membranes, it was shown that they were the complex extensions or invaginations of cell membranes. Neither myelin-axon complexes nor myofilaments, including Z band material, were seen in any case. There was a possibility that the smooth tubular aggregate was a T-tubule-like structure, suggesting that the tumors were derived from skeletal muscle cells.