Takasi Kobayasi

The ultrastructural changes of Leishmania tropica after treatment with pentamidine.

The effect of the antiprotozoal drug pentamidine on the ultrastructure of the amastigote stage of Leishmania tropica was studied. The most remarkable change introduced by the treatment occurred in the kinetoplast-mitochondrion complex. All mitochondria were extremely enlarged and most kinetoplasts disintegrated into a network of fine filaments. The flagellar pocket was frequently dilated and filled with various quantities of double-membrane bounded bodies ejected from the pocket wall. The multivesicular bodies and lipid droplets were enlarged. The number of ribosomal granules decreased. Many protozoa had an irregular shape and damaged internal structure. The drug-induced changes of L. tropica are discussed in relation to similar effects previously observed in trypanosomes.

Dermatomyositis with universal calcinosis. A histopathological and electron optic study.

Biopsies from a 5‐year‐old girl with dermatomyositis and universal calcinosis were studied histo‐pathologically and by means of electron optical techniques. The dermis was infiltrated by fibro‐blasts, lymphocytes and plasma cells. In the lower part of the dermis, dense basophilic areas were present. In the vicinity of these areas irregular elastic fibers appeared. In the electron microscope these elastic fibers appeared mineralized to varying degrees. The mineral part was identified as calcium apatite (either calcium‐hydroxy‐apatite or calcium fluoroapatite) by X‐ray microanalysis and selected area diffraction. No calcification was observed outside the elastic fibers.

Toxicology of triethyllead, methylmercury and cadmium, determined in chick embryo brain cell cultures.

The toxicology of water soluble chemical compounds may be investigated in tissue culture systems. The toxicology of triethyllead chloride, methylmercury chloride and cadmium acetate was studied in chick embryo brain cell cutlures. Tetraethyllead is added to petrol as an anti-knock agent. When tetraethyllead is absorbed by the organism, it is converted to triethyllead which cause the symptoms of tetraethyllead poisoning. Chick embryo brain cell cultures derived from cerebrum of 11-day-old chick embryos developed both neurons and glial cells. The neurons formed nerve processes and synapsis in the cultures. The effect of triethyllead chloride was investigated by addition of triethyllead chloride to the nutrient medium. The median tissue culture lethal dose, TCLD50 = 1.9 mg/l, was determined as the concentration of triethyllead chloride at which the confluent layer of glial cells was destroyed in 50% of the cultures. The neurons lost their processes at even lower concentration, TCED50 = 0.57 mg/l. Electron microscopy revealed cells with swollen Golgi apparatus and dilated endoplasmic reticulum in chick embryo brain cell cultures which were treated with triethyllead chloride, 1.0 mg/l. Studies with radioactive labelled precursors revealed that triethyllead chloride inhibited the synthesis of DNA, sulfatides and cerebrosides without hydroxyfatty acids.

Ruthenium Red staining of ultrathin sections of human mast-cell granules†

Ruthenium Red was used for staining glutaraldehyde‐fixed ultrathin sections of mast cells embedded in Epon 812. The dye was dissolved in 0.1 M ammonia, or 0.1 N acetic acid or phosphate buffer at pH 7.4, 0.1 M at a concentration of 0.5%. The ammoniacal solution stained acid mucopolysaccharides of human mast‐cell granules more specifically than did the acetic solution. The probable site of the acid mucopolysaccharides is the finely granular material within the granules.

Filamentous aggregates of collagen. Ultrastructural evidence for collagen-fibril degradation in situ

SummaryFilamentous aggregates of collagen are distinct structures in the pathological dermis. These aggregates are distinguishable from fibrous long-spacing collagen (in vitro and at biopsy) and the Luse body. The aggregates are produced from dermal collagen fibrils by clostridial collagenase and culture-medium extract, which supposedly contains cellular collagenase at a neutral pH, as well as by organ cultures. In vitro experiments showed that carrageenan granuloma contains fibrous long-spacing collagen and segment long-spacing collagen. The granuloma also contains the aggregates. The aggregates were found in skin biopsies from syphilitic chancres, acrosclerotic scleroderma, morphea, mycosis fungoides, myeloid leukemia, mastocytosis and malignant melanoma. These findings indicate that the aggregates are products of the in situ degradation of collagen fibrils by some collagenolytic factor. This factor may originate in fibroblast-like cells, reticulum cells, leukemia cells, mast cells and melanoma cells.

Ultrastructure of prolapsed disc

Prolapsed tissue and removed interspace contents were obtained during hemilaminectomy for disc prolapse. The ultrastructure of the tissue was studied. Division of the material into annulus fibrosus and nucleus pulposus proved to be inaccurate. Chondrocytes were always the predominant cell type and could be classified into normal, cloning and necrotized types. Matrix vesicles were found in relation to the haloes of chondrocytes and seemed to be products of disintegrated chondrocytes. Findings of crystals in the vesicles were rare. The intercellular substance showed degraded collagen fibrils, which could be seen in spindle shaped cells as well. A dense amorphous material interpersed with collagen fibrils seemed to be a glycoprotein. A few elastic fibres were found, but without any evidence of severe degeneration. These findings represent changes occuring in cells and in the intercellular substance.

Dermal changes in Ehlers‐Danlos syndrome

Skin biopsies from thirteen patients suffering from Ehlers‐Danlos syndrome, including 6 of the mitis type, 4 of the benign hypermobile type, one of the X‐linked type, one of the ocular type and one of the periodontitis type, were studied by electron microscopy after routine preparation.

Desmosome-like structures in acantholytic epidermal cells of contact dermatitis.

SummaryThe cytoplasm of acantholytic epithelial cells found in epidermal vesicles of contact dermatitis due to tetramethyl-thiuram disulfide contained desmosome-like organelles. The fine structure was identical with that of surface desmo-somes of normal epidermal cells except for the fact that the lucent zone encircles the inner lamella. This zone seems to occur in intracytoplasmic desmosome-like structures from different sources.ZusammenfassungDesmosomenähnliche Strukturen wurden im Cytoplasma acantholytischer Epidermiszellen in Bläschen einer Tetramethylthiuramdisulfid-Kontaktdermatitis elektronenmikroskopisch nachgewiesen. Ihre Ultrastruktur war mit den an Zelloberflächen auftretenden normalen Desmosomen identisch. Jedoch war in den intracytoplasmatischen Desmosomen die Innenlamelle von einer hellen Zone umgeben.

DERMO-EPIDERMAL JUNCTION OF NORMAL SKIN

The dermo‐epidermal junction is a complex structure, composed of semidesmosomes (attachment plaque, cell membrane and junction plate) anchoring filaments, basal lamina, anchoring fibrils and elastic fibrils. A similar structure is seen in other epithelial and endothelial tissues, muscles and nerves. Among them, mucous epithelium is very like the epithelium of skin.

Elastic Fibers in Dermis of Juvenile Elastoma

To explore the ultrastructure of elastic fibers in juvenile elastoma, three patients (two without osteopoikilosis and one under examination of bones and joints) were studied by routine electron microscopy. In addition to normal elastic fibers, all the patients also exhibited alterations in elastic fibers. The altered ultrastructures showed lucent, homogenous matrix without peripheral microfibrils. The homogenous matrix were seen in various extensions from the small protrusions of the normal elastic fibers to the complete replacement of the entire fibers. Collagen fibrils occasionally showed twisted figures. Normal shapes of dermal glycosaminoglycans were increased in number. It seems likely that the lucent, homogenous matrix without peripheral microfibrils are the characteristic changes of elastic fibers in juvenile elastoma. The alteration could be nevoid in nature.