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Biomedical subjects

T Kobayasi

Publications and source records attributed to T Kobayasi.

At least 73 records · Page 4Linked to original sources
PubMed1979

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

Biopsies from a 5-year-old girl with dermatomyositis and universal calcinosis were studied histopathologically and by means of electron optical techniques. The dermis was infiltrated by fibroblasts, 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.

Calcinosis↗
PubMed1979

[The dermoepidermal junction in skin diseases].

Dermatological conditions characterized by dermo-epidermal separation, basal lamina discontinuity, multiplication, and thickness variability, and/or irregularity of the subepidermal space are discribed. Pathological changes of the dermo-epidermal junction are considered to be destructive or reproductive. Both may appear in combination. Destructive processes may be relfected by dermo-epidermal separation. Epidermal cells and/or dermal connective tissue appear degenerated. Thickening of the lamina may occur by reactive hyperproduction or by precipitation of pathological materials. Reproductive processes of the junction originate in the epidermal cells and are reflected in multilayering of the basal lamina. Interruption of the lamina and irregularity of the subepidermal space often precede these phenomena.

Dermatitis↗
PubMed1979

Adult human skin maintained in organ culture: I. The ultrastructure of the acellular compartment of connective tissue.

Collagenolytic enzymes are produced by cultured skin explants. During cultivation the acellular compartment of the dermal connective tissues is digested away. The ultrastructure of the connective tissue resorption has been studied in human skin maintained in organ culture for 2--10 weeks. The connective tissue changes are: (1) Collagen fibrils with normal axial periodicity but decreasing diameters. On cross sections these fibrils have irregular outlines, while the longitudinal sections show fibrils separated into thin bundles of filaments 40--80 A thick with preserved normal axial periodicity. (2) Cross-banded filamentous aggregations (CBFA) consisting of fine parallel filaments 25 A thick and without axial periodicity. The CBFA has 350 A thick bands at 525 A intervals. At the end of the cultivation, the CBFA are replaced by solitary filaments 25 A thick. (3) The elastic fibres show no marked changes of the amorphous matrix, while the fibrils disappear. The loss of collagen and elastic fibrils during cultivation of the skin gives direct evidence of connective tissue degradation. The described changes are discussed in relation to previous ultrastructural studies on connective tissue resorption of various tissues.

Adolescent↗
PubMed1979

Ultrastructure of skin in primary systemic amyloidosis.

Amyloid masses were found in the dermis of two brothers suffering from primary amyloidosis. The masses consisted of fibrils, composed in turn of twin hollow filaments of amyloid. An amyloid filament appeared as a 3 nm thick lucent core with a 2 nm thick wall. Occasionally 4--6 filaments were packed together in one fibril. The twin filaments were slightly twisted, with a twisting angle of 2.5 degrees and a coiling pitch of 1 160 nm. Wavy shapes of amyloid fibrils were also seen in elastic fibres. Amyloid fibrils were found in elastic fibres, under the basal lamina of the epidermis, sweat gland epithelium and Schwann cells; also around perineural cells, perivascular cells and, in one of the brothers, in collagen fibril bundles. No amyloid fibrils were found under the endothelial basal lamina. It would appear that amyloid fibrils are pathological fibrils belonging to the elastic fibre-basal lamina system.

Aged↗
PubMed1979

Intracellular collagen fibrils in cultured human skin.

During cultivation, the collagen fibrils of skin explants are broken down. The cells of the explants participate in this resorption. The ultrastructure of the intracellular degradation of collagen fibrils of cultured human skin has been examined. Intracellular collagen fibrils occur in fibroblasts, macrophages, smooth muscle cells and unidentifiable cells. Normal collagen fibrils are engulfed and appear within membrane-bounded tubes of the cytoplasm. Primary lysosomes fuse with the tubes. Degraded intracellular collagen fibrils are frequently present in secondary lysosomes and show decreasing diameters, filamentous splitting, loss of axial periodicity, variable stainability and cross-banded filamentous aggregates. The changes in the intracellular collagen fibrils are identical with those seen in the extracellular space. The present study demonstrates that various cell types in dermis are involved in collagen fibril degradation and that the lysosomes play an important part in the intracellular resorption.

Cells, Cultured↗
PubMed1978

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.

Animals↗
PubMed1978

Enzymatic liberation of viable cells of human skin.

To obtain viable cells from normal human skin, clostridial collagenase was used. Crude collagenase digestion of collagen fibres and basal lamina results in free dermal cells and sheets of epidermis. The collagenase was tested at various concentrations, solvents and incubation periods. The specimens digested were either split or full thickness skin of varying size. The optimal result was obtained by using small (3mm across) split skin pieces incubated in 2 mg/ml collagenase. The choice of solvent MEM, MEM supplemented with serum, and Tris buffer, was less important. 3 hours' incubation the epidermis was peeled off in sheets and finally dissociated by trypsin-EDTA. The corium was completely digested after 6 hours. After 6 hours' incubation no viable cells could be seen. The epidermal cells appeared mainly as polygonal cells of various sizes and a few little dendritic cells. The dermal cells had a heterogeneous morphology during the first weeks of cultivation. After 2 weeks the cells appeared as fibroblast-like cells.

Cell Separation↗
PubMed1978

Salpeter-induced dermal changes electron-microscopically indistinguishable from pseudoxanthoma elasticum.

Salpeter-induced calcium deposits in ten patients showed a close clinical and histopathological similarity to the lesions of pseudoxanthoma elasticum. By electron microscopy and selected area diffraction analyses of the calcium deposits we find the changes indistinguishable from the changes previously described in involved skin of patients suffering from PXE. Clinically our patients were compared with the fourteen patients with traumatic calcification previously described.

Aged↗
PubMed1977

Electron microscopic cytochemical demonstration of adenyl cyclase activity in psoriatic epidermis.

Isoproterenol and sodium fluoride stimulated adenyl cyclase activity was detected in epidermal tissue from 2 patients with untreated psoriasis by an electron microscopic cytochemical technique. Adenyl cyclase activity was present on the outer surface of the cell membranes, predominantly in the basal cells and in the 4-5 lower Malpighian cell layers, while the superficial layers, stratum granulosum and stratum corneum showed no activity. The precipitates (lead-PPi complexes) after isoproterenol stimulation were larger and fewer in number than those seen after sodium fluoride stimulation. Isoproterenol stimulation was abolished by propranolol. Neither the uninvolved epidermis from the 2 patients with psoriasis nor the normal skin from 2 volunteer individuals showed any difference from the psoriatic epidermis.

Adenylyl Cyclases↗
PubMed1977

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.

Amidines↗
PubMed1977

The ultrastructure of Leishmania tropica in skin lesions.

The ultrastructure of the amastigote stage of Leishmania tropica has been studied. The present work reports on new observations on the fine structure of the basal body, prokinosome and flagellum. The basal body is composed of a centriole-like structure and a transitional zone continuous with the proximal part of the flagellum. The centriole-like part consists of nine peripheral triplet tubules and an indistinct dense central core. The transitional zone consists of nine peripheral doublet tubules and two central cylinders. The centriole-like prokinosome is present parallel and close to the basal body. The flagellum arises from the transitional zone of the body and has the classical axoneme (9+2) structure. However, at the tip of the flagellum the central tubules are replaced by one of the peripheral doublet tubules. The ultrastructural findings, as compared with previous studies of Leishmania, are discussed.

Adult↗
PubMed1977

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.

Adult↗
PubMed1977

Ultrastructural changes in disseminated connective tissue nevi.

Skin biopsy specimens from a patient with disseminated connective tissue nevi and from her son and daughter who had no such clinical alterations were studied with the electron microscope. The nevi showed increased amounts of thick elastic fibres, which were composed of irregularly arranged, often finger-like, subunits surrounded by a thready material. Both structures probably represent malformed components of elastic fibres, the thready material representing malformed elastic fibrils. Many of the collagen fibrils showed increased diameters and twistings, which alterations are believed to represent malformation of collagen. The fibroblasts showed changes which might be related to a pathological protein synthesis. Examination of biopsy specimens from normal skin of the patient and from the skin of her son and daughter failed to demonstrate similar alterations. The present case is regarded as an entity, distinct from dermatofibrosis lenticularis disseminata and from shagreen patch.

Adult↗
PubMed1977

Ultrastructure of dermal connective tissue in fibrodysplasia ossificians progressiva.

The ultrastructure of dermal connective tissue in two patients suffering from fibrodysplasia ossificans progressiva (syn myositis o.p.) was studied. The disorder starts with soft tissue swelling which subsequently ossify. The connective tissue of various organs may be affected. No defects in calcium metabolism have been discovered. It was intended to study the primary event which initiates the ossification. The present ultrastructural study demonstrates an accumulation of proteoglycan microfibrils as well as glycoprotein material in dermal connective tissue. Both substances are prerequisites of calcification resulting from the binding of calcium and phosphorus ions. A subsequent release of proteolytic enzymes in the tissues may be set free the bound iones and, thus, initiate mineralization.

Calcium↗