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Biomedical subjects

K M Kim

Publications and source records attributed to K M Kim.

At least 217 records · Page 12Linked to original sources
PubMed1985

Survival and growth of adult human oligodendrocytes in culture: scanning electron microscopy.

The oligodendrocytes in culture serve as an important model for the study of demyelination diseases. We have previously originated a method of isolating human oligodendrocytes. In order to establish their three dimensional morphology, scanning electron microscopy of the cultured oligodendrocytes was performed. The oligodendrocytes bulk isolated from adult human brain were maintained in culture for more than 2 months. At the various periods in culture, the cells were studied by scanning electron microscopy and immunofluorescence staining using marker antibodies for the identification of oligodendrocytes. The three dimensional organization and the surface morphology of the cultured oligodendrocytes were investigated. They displayed an extensive network of the cell processes and characteristic surface morphology.

Adult↗
PubMed1985

The growth of fetal human sensory ganglion neurons in culture: a scanning electron microscopic study.

Sensory neurons of 8-week human fetal dorsal root ganglia were dissociated into single cells by trypsinization and cultured on coverslips for 4 months, in either serum-containing or serum-free chemically defined media. At different times the cultures were fixed and prepared for scanning electron microscopy. Fetal sensory neurons in culture regenerated axons within 24 hours which were characterized by axonal growth cones at their tips and the neuronal perikarya assumed spherical or a bonnet-like morphology.

Axons↗
PubMed1984

Cell injury and calcification of rat aorta in vitro.

In order to study the mechanism of dystrophic calcification of vascular connective tissue as a result of cell injury, anoxic incubation and organ culture in CMRL 1066 of fresh and freeze thawed rat aorta and serum incubation of fresh rat aorta were performed. Calcium concentration of the culture medium was adjusted to 2.5mM and phosphate to 0.9mM. Calcium depletion from the culture medium continued for 3 weeks and then plateaued. In every experiment, calcification was seen predominantly in association with the membranous cellular degradation products derived from degenerated smooth muscle cells. These were morphologically similar to the matrix vesicles. In the areas of massive necrosis, particularly in the freeze thawed aortic tissue, massive calcification extending to collagen and elastic fibers was seen. Of the various membranous cellular degradation products, mitochondrial inner membrane also appeared to serve as one of the nidi of calcification. Influx of extracellular Ca2+, which results from suppression of ion pumps upon cell injury, to PO4(3-) rich cytosol is thought to play a pivotal role in dystrophic calcification. Phosphatidyl serine located along the inner surface of the plasma membrane or the membranous vesicle may serve as the substrate for heterogeneous nucleation of apatite. Calcification of the cellular degradation products which was more pronounced in freeze thawed aorta is apparently non-energy dependent. Calcification of the elastic and collagen fibers evidently occurs as an extension from the calcified cellular degradation products.

Animals↗
PubMed1984

Scanning electron microscopy of urinary stone as a diagnostic tool.

On the basis of an extensive electron microscopic study of human urinary stones, a step by step method of stone analysis by scanning electron microscopy (SEM) morphology was developed. A preliminary blind study of 100 consecutive stones demonstrated that the method requires minimum amounts of training and is highly accurate. With several hours of training, accuracy of the stone analysis by SEM morphology alone exceeded 95%. The data indicate that, with further refinements, SEM stone analysis can be accomplished expeditiously and exceed other methods known for stone analysis with economy and accuracy.

Crystallization↗
PubMed1983

Siliceous deposits in human urinary calculi--an E. M. study.

Silica calculi in man are extremely rare; only 12 cases have been reported. In an electron microscopic study of human urinary stones, siliceous deposits were encountered in three out of 180 stones as a discrete component of stones. There were no histories of magnesium trisilicate administration in these cases. Morphology of the deposits was distinctive from any other components of the stones and bore some resemblance to animal silica calculi. Siliceous deposits in human urinary stones appear to be more common than generally recognized.

Electron Probe Microanalysis↗
PubMed1983

Mulberry particles formed by red blood cells in human weddelite stones.

In a series of electron microscopic studies of human urinary stones, mulberry shaped particles were observed in 5 out of 51 calcium oxalate dihydrate (COD) containing stones. The mulberries were crenation products of red blood cells which adhered to the surface of bipyramid COD crystals, followed by impregnation of the COD. The red cells appeared to participate in the crystal growth by creating foci of surface nucleation, or by formation of a layer of crust on the surface of the bipyramids which caused deposition of an additional layer of calcium oxalate. The lipid containing organic matrix seems to have a role in COD crystal growth.

Calcium↗
PubMed1983

Exogastric leiomyosarcoma with ultrastructural analysis.

A 50-year-old man was found to have a large exogastric leiomyosarcoma during exploratory laparotomy for a bleeding duodenal ulcer. Although the tumor appeared grossly malignant and was associated with small bowel metastases, its light microscopic appearance was relatively benign. Electron microscopy helped to established the diagnosis of gastric leiomyosarcoma.

Duodenal Ulcer↗
PubMed1983

Dense-core matrical mitochondrial bodies in oncocytic adenoma of the thyroid.

Single and/or multiple, round and homogeneous electron-dense bodies occurred within the mitochondrial matrix of a mitochondrion-rich follicular adenoma of the thyroid. These non-membrane-bound bodies varied greatly in size and often occupied a large portion of the mitochondrion. They were present in normal-sized or large mitochondria that exhibited cristolysis and/or dilatation of the intracristal space of the residual cristae and formation of intramatrical myelin figures. The globule-containing mitochondria frequently exhibited bundles of parallel intramatrical filamentous inclusions that were 6 to 8 nm in width and were randomly arranged in clusters. Megamitochondria up to 4.4 micrometers in widest diameter occurred in a frequency of one to two per cell and they displayed similar bundles of filamentous inclusions. This evidence of electron-dense bodies in non-steroid-hormone-secreting cells suggests that the bodies result from nonspecific mitochondrial reaction to injury rather than being inclusions specific for steroid-synthesizing cells.

Adenoma↗
PubMed1983

Lipid matrix of dystrophic calcification and urinary stone.

The concept that phospholipids, phosphatidyl serine (PS) in particular, play a role in tissue calcification has emerged recently and progressed rapidly. Membranous cellular degradation products upon various tissue injuries apparently serve as nidi of calcium apatite nucleation. In view of the strong affinity of calcium for PS, and the frequent occurrence of calcification in apposition to the inner surface of membrane where PS resides, it is concluded that exposure of PS to the extracellular fluid with a high calcium concentration upon cell injury is largely responsible for the dystrophic calcification. An abundance of membranous vesicles and other unidentified organic matrices were visualized in decalcified urinary stones. The findings also indicate the prospect of the role of degenerate cell membrane in stone formation as well. Furthermore, red cells adherent to bipyramid calcium oxalate dihydrate crystals apparently enhance crystal growth by mechanism analogous to the kink site formation. Lipid matrix in the form of membrane plays an important role in dystrophic calcification as well as calcium containing stone formation.

Animals↗
PubMed1983

Nephrocalcinosis in vitro.

In order to study the mechanism of dystrophic calcification, an anoxic incubation of rat renal cortex in a tissue culture medium was performed in vitro. Calcium and phosphate in the medium were adjusted to 1.6 and 1.2 mM/1 respectively. Calcification occurred in apposition to the inner surface of membranous cellular degradation products and associated with the flocculent densities within the degenerate organelles. The chemical nature of the flocculent density was not determined. In view of the known affinity of calcium for acidic phospholipids, particularly phosphatidyl serine (PS), which lines the inner surface of the plasma membrane, calcification along the inner surface of membrane was thought to be related to the presence of PS. Accumulation of calcium in mitochondria, which is presumably dependent upon residual substrate for energy production, appeared to cause calcification as well. Amorphous calcium phosphate in the form of spheroids, and possibly fine fibrils and granules, also appeared to play a role in calcification by their transformation into apatite. The seemingly simple phenomenon of tissue calcification is complex. Nephrocalcinosis in vitro is remarkably similar to the calcification in acute tubular necrosis in vivo, and is a convenient model with which to study the mechanism of calcification. It is concluded that the cellular degradation products are the initial loci of calcification and have a likely role in urolithiasis.

Animals↗
PubMed1982

beta-Fibrillary bodies in low-grade adenocarcinoma of parotid gland: a histochemical and ultrastructural study.

Rounded or polyhedral, acellular, dense lamellated structures were seen within the cystic and glandular spaces in a case of low-grade papillary adenocarcinoma of the parotid gland. These structures displayed the histochemical characteristics of amyloid, namely, pink color with apple-green birefringence and bright red fluorescence with alkaline congo red, orthochromasia and red birefringence with standardized toluidine blue, positive dimethylaminobenzaldehyde nitrite and diazotization coupling reactions, and spontaneous autofluorescence. At the ultrastructural level the tumor consisted of cuboid, flattened, or elongated epithelial cells with varying degrees of differentiation, but most mature tumor cells had numerous intracellular intermediate filaments. These filaments were randomly oriented and had no lateral fasciation; they were 10 nm wide and similar to those constituting the intraluminal corpora amylacea. These bodies displayed increased fibrillary density. Cellular organelles and pyknotic nuclei were frequently present at the periphery of the fibrillary masses. Amyloid masses, histochemically and ultrastructurally indistinguishable from those in the lumens, were present in the stroma as well. It is postulated that both stromal and intraluminal beta-fibrillary bodies result from apoptosis and desquamation of neoplastic cells, with progressive release and confluency of intracellular intermediate filaments within closed cystic spaces. This additional evidence of beta-fibrillosis associated with a slow-growing non-hormone-secreting salivary gland tumor suggests that these tumors may be associated with amyloidosis more frequently than was previously suspected.

Adenocarcinoma, Papillary↗
PubMed1982

The stones.

Various stones were examined by a combined electron microscopy. Morphological parameters of calcium oxalates and phosphates, struvite, urates, cystine, gypsum, siliceous deposits in urinary, prostatic and salivary calculi, and calcium carbonate in gallstones were defined. Study also disclosed that stones frequently contain organic crystals in addition to the organic matrix. Membranous cell debris was observed in the nuclei of small stones and were believed to be common nidus of various stones. In view of a very limited number of crystals occurring in human stones, which differ obviously in their habits and growth patterns, an expeditious identification of stone components is possible by scanning electron microscopy. SEM with x-ray analysis is a powerful tool for research and diagnosis of various stones. It is most suitable for the study of surface phenomena, such as crystal growth, detection of phenomena, such as crystal growth, detection of organic matrix and minor components of the stones, and is a wide open field for a further study.

Calculi↗
PubMed1981

Calcium oxalate crystal growth in human urinary stones.

Calcium oxalate stones are very common and increasing. Crystal growth is no less important than the crystal nucleation in the pathogenesis of stone formation. The crystal growth was studied in human calcium oxalate stones by a combined electron microscopy and x-ray diffraction. The main mode of weddellite growth was interpenetration twinning of tetrahedral bipyramids. Bipyramids may form as initial crystal seeds, develop from anhedral crystals (crystals which lack flat symmetric faces) of spherular or mulberry shape, develop on the surface of preformed bipyramids by spiral dislocation mechanisms, or develop on whewellite crystal by heterogeneous nucleation and epitaxy. Heterogeneous nucleations of whewellite on weddellite, and calcium apatite on whewellite were also observed. Whewellite grew mainly by parallel twinning. Interpenetration twinning was exceptional. Transformation of anhedral to euhedral (completely bounded by flat faces that are set ar fixed angles to one another) whewellite occurred by parallel fissurations followed by brick wall like stacking of the crystals, while euhedral transformation of weddellite occurred by protrusion of bipyramids frm anhedral crystal surface. Occasionally, an evidence of crystal dissolution was noted. Although an aggregation of crystals is believed to play a pivotal role in stone nidus formation, growth in size of the formed crystals, and twinning and epitactic crystal intergrowth apparently play a significant role in the obstructive urinary stone formation.

Calcium Oxalate↗
PubMed1979

X-ray analysis of pathological calcifications including urinary stones.

Electron-probe microanalysis (EPM) is an ideal technique with which to study biological calcification. It is particularly effective in identification of crystalline or non-crystalline deposits of minute size in tissues, and in detecting artifacts which may occur during tissue processing. Human aorta, aortic valves, tumours, joint fluid, and calculus specimens were analyzed via scanning electron microscopy (SEM), EPM, transmission electron microscopy (TEM), and selected-area electron diffraction (ED). Crystals found in the specimens were definitively identified by combined SEM-EPM. It is apparent that EPM is an invaluable tool that will potentially improve the acuity of 'in house' laboratory diagnosis of many pathological calcifications.

Aorta↗
PubMed1977

[Prevention of complications of histamine liberation occurring after administration of anesthetic agents and adjuvants].

To protect the organism against histamine liberated during anesthesia specific premedication is used including:--hydroxyzine (Atarax) which blocks the H1 histamine receptors, and is an anxiolytic,--tritoqualine (Hypostamine) which inhibits histamine synthesis,--epsilon aminocaproic acid (Hemocaprol) which prevents the antigen-antibody reaction and blocks the alternate route of complement. Twenty five patients were thus premedicated, 25 others received no premedication. All were put to sleep with Alfatesine. The results were judged on the clinical symptoms and the variations of histamine in whole blood. This premedication seems very efficacious, in particular in subjects with a high risk of histamine liberation.

Adjuvants, Anesthesia↗
PubMed1976

Aging changes in the human aortic valve in relation to dystrophic calcification.

To elucidate the pathogenesis of aging changes and their relation to age associated calcification, a morphological study of 27 human aortic valves was carried out. Nine valves were obtained from immediate autopsies and 18 valves from routine autopsies done within four hours after death. Calcium deposition was present deep in the zona fibrosa along a zone of lipid accumulation. Fibrocytes in the zona fibrosa showed predominant age associated changes, i.e., a massive accumulation of residual bodies in the cytoplasm probably derived from autophagic vacuoles. Light microscopic lipid accumulation corresponded with both intracellular accumulation of electron dense spherules and membranous vesicles derived from degenerate fibrocytes. Calcium deposition in various stages, including needle shaped hydroxyapatite crystals, was seen in close association with these cellular degradation products rather than collagen or elastic fibers. Dystrophic calcification in the aortic valve appears to result from cellular aging and death followed by petrification of cellular degradation products, which may progress to calcific aortic stenosis.

Adolescent↗
PubMed1976

Calcification of matrix vesicles in human aortic valve and aortic media.

Calcification of human aortic valve and aortic media occurs regularly, increases with age, and is distinctively associated with a zone of lipid accumulation. Ultrastructurally, the accumulated lipids are seen as cellular degradation products derived from senescent and degenerate fibrocytes and smooth muscle cells. The products when deposited in the matrix are morphologically similar to the matrix vesicles described in other calcifying tissues, and serve as the initial site of calcification rather than collagen or elastic fibers. Scattered among the smaller and more typical matrix vesicles, there are seen frequently giant vesicle-like structures measuring several microns in diameter. Many of these large calcified bodies contain needle-shaped, radially arranged apatite crystal deposits. Some of the large calcifying bodies are bounded by folded structures suggesting a membrane component, at times obscured by a more dense floccular osmiophilic deposition. Alcianophilic apparent proteoglycan particles are also adherent to these large calcified bodies. The substance forming the large calcified bodies might be a complex of phospholipids derived from cell membrane and proteoglycan derived from ground substance, this combination possible serving as a nidus for calcification.

Age Factors↗