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Biomedical subjects

M Takeichi

Publications and source records attributed to M Takeichi.

At least 235 records · Page 13Linked to original sources
PubMed1978

Familial juvenile neuronal storage disease. New disease or variant of juvenile lipidosis?

Two patients had an illness characterized by a positive family history, juvenile onset, macular cherry-red spots, myoclonus, generalized convulsions, and cerebellar ataxia. Neither had dementia, gargoyle facies, bone or joint deformities, or visceromegaly. Vacuolated lymphocytes were not seen in the peripheral blood or bone marrow. Specimens from the rectum and vermiform appendix showed Sudan black B-, Sudan III-, and PAS-positive granules within the neurons of the myenteric plexus. On electron microscopic examination, lysosome-like bodies, membranous cytoplasmic bodies, pleomorphic lamellated bodies, dense bodies, and lipofuscin-like bodies in the neurons were seen, with a suggestion of morphological transitional forms among them. Sialoglycopeptides, especially sialic acid, were increased in the urine, but excretion of acid mucopolysaccharides was normal. Assays of lysosomal enzymes in leucocytes showed normal enzymatic activity. On the basis of the clinical, biochemical, and histological results, we suggest that these two cases and four similar cases reported in the literature be classified differently from the previously described lipidoses, although it is not known whether these cases represent a new entity or merely a clinical variant of juvenile lipidosis.

Adolescent↗
PubMed1977

Adhesion of phospholipid vesicles to Chinese hamster fibroblasts. Role of cell surface proteins.

The adhesion of artificially generated lipid membrane vesicles to Chinese hamster V79 fibroblasts in suspension was used as a model system for studying membrane interactions. Below their gel-liquid crystalline phase transition temperature, vesicles comprised of dipalmitoyl lecithin (DPL) or dimyristoyl lecithin (DML) absorbed to the surfaces of EDTA- dissociated cells. These adherent vesicles could not be removed by repeated washings of the treated cells but could be released into the medium by treatment with trypsin. EM autoradiographic studies of cells treated with[(3)H]DML or [(3)H]DPL vesicles showed that most of the radioactive lipids were confined to the cell periphery. Scanning electron microscopy and fluorescence microscopy further confirmed the presence of adherent vesicles at the cell surface. Adhesion of DML or DPL vesicles to EDTA-dissociated cells modified the lactoperoxidase-catalyzed iodination pattern of the cell surface proteins; the inhibition of labeling of two proteins with an approximately 60,000- dalton mol wt was particularly evident. Incubation of cells wit h (3)H-lipid vesicles followed by sodium dodecyl sulfate (SDS)- polyacrylamide gel electrophoresis showed that some of the (3)H-lipid migrated preferentially with these approximately 60,000-mol wt proteins. Studies of the temperature dependence of vesicle uptake and subsequent release by trypsin showed that DML or DPL vesicle adhesion to EDTA- dissociated cells increased with decreasing temperatures. In contrast, cells trypsinized before incubation with vesicles showed practically no temperature dependence of vesicle uptake. These results suggest two pathways for adhesion of lipid vesicles to the cell surface-a temperature-sensitive one involving cell surface proteins, and a temperature-independent one. These findings are discussed in terms of current models for cell-cell interactions.

Adsorption↗
PubMed1977

Functional correlation between cell adhesive properties and some cell surface proteins.

The adhesive properties of Chinese hamster V79 cells were analyzed and characterized by various cell dissociation treatments. The comparisons of aggregability among cells dissociated with EDTA, trypsin + Ca2+, and trypsin + EDTA, revealed that these cells have two adhesion mechanisms, a Ca2+-independent and a Ca2+-dependent one. The former did not depend on temperature, whereas the latter occurred only at physiological temperatures. Both mechanisms were trypsin sensitive, but the Ca2+-dependent one was protected by Ca2+ against trypsinization. In morphological studies, the Ca2+-independent adhesion appeared to be a simple agglutination or flocculation of cells, whereas the Ca2+-dependent adhesion seemed to be more physiological, being accompanied by cell deformation resulting in the increase of contact area between adjacent cells. Lactoperoxidase-catalyzed iodination of cell surface proteins revealed that several proteins are more intensely labeled in cells with Ca2+-independent adhesiveness than in cells without that property. It was also found that a cell surface protein with a molecular weight of approximately 150,000 is present only in cells with Ca2+-dependent adhesiveness. The iodination and trypsinization of this protein were protected by Ca2+, suggesting its reactivity to Ca2+. Possible mechanisms for each adhesion property are discussed, taking into account the correlation of these proteins with cell adhesiveness.

Animals↗
PubMed1976

Different cation requirements for aggregation of BHK cells and their transformed derivatives.

BHK21 cells singly dissociated by trypsin aggregate in medium with calcium ions, but not in medium with magnesium ions. Their malignant derivatives (pyBHK) induced by polyoma virus, after dissociation with trypsin, aggregate equally well in medium with either calcium or magnesium ions. When EDTA is used for dissociation of cells from culture on a substrate, neither BHK21 nor pyBHK cells require addition to the medium of divalent cations for rapid aggregation. Trypsin-dissociated BHK21 cells become aggregative in medium without divalent cations, when they are incubated for 60 min in dispersion with medium containing calcium ions before aggregation. In the case of pyBHK cells, incubation in dispersion in the medium with calcium or magnesium ions is effective in this respect. Calcium and magnesium ions are equally effective for adhesion of both BHK21 and pyBHK cells to non-cellular substrate or to a cell monolayer. We discuss the different cation requirements for aggregation of BHK21 and their transformed derivatives in relation to the recovery process of cell surfaces after exposure to trypsin.

Calcium↗
PubMed1975

Ultrastructure of intracisternally accumulated dense particles observed in nerve cells of rat cerebellar nuclei.

Peculiar dense particles were accumulated within smooth-surfaced cisternae of some neuronal perilarya of cerebellar nuclei in rat. The particles were 200-450 A in size and spheroidal or slightly irregular in outline. They were low in contrast after uranyl acetate treatment, whereas they showed increase in electron density after uranyl and lead staining. Wigh respect to the possible nature of these intracisternal dense particles, the following interpretation was discussed. The particles concerned were probably identified as glycogen which had been synthetized by the agranular endoplasmic reticulum as an unusual cytological event.

Animals↗
PubMed1975

Effect of L-dopa administration to fine structures of brain, heart and kidney in rats, with special reference to appearance of microvascular thrombosis and its pathological significance.

L-dopa (100-200 mg/kg/day) was given orally to rats for one, two, or three months. The cerebrum, cerebellum, heart and kidney were then examined using the light and electron microscope. With the light microscope, there was observed the occurrence of small hemorrhagic foci and occlusion of the capillaries, venules and occasionally small veins by amorphorus eosinophilic material or agglutinating red blood cells in all the tissues examined. On the other hand, with the electron microscope, there was seen the presence of two distinct changes in the brain, heart and kidney, which were never found in the corresponding tissues from the control rats. One was concerned with intravascular abnormalities, i.e. formation of thrombi in the microvasculatures. Above all, microthrombi that were thought to be equivalent to amorphous eosinophilic material in light microscopy consisted of diffusely distributed, electron-dense, fine granular substances and randomly scattered, much electron-denser, large granular material. The other was concerned with mitochondrial alterations in the parachymal cells, i.e. nerve cells, cardiac muscle cells and renal parenchymal cells. In general all the changes that were detected by search at both light and electron microscopic levels tended to be developed increasingly with prolongation of the period to sacrifice from commencement of L-dopa administration so that effect of L-dopa on their formation was apparently time related.

Animals↗