Browsing by Author "MUNIZAGA, A"

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    DISTRIBUTION OF INTERMEDIATE FILAMENTS IN EPITHELIAL-CELLS OF THE AMPHIBIAN URINARY-BLADDER - AN IMMUNOFLUORESCENCE STUDY
    (1989) DABIKE, M; MUNIZAGA, A; KOENIG, CS
    The distribution of intermediate filaments in toad and frog urinary bladder was studied on frozen sections by indirect immunofluorescence microscopy using specific antiprekeratin antibodies. Our results show that in both species, epithelial cells lining the urinary bladder are very rich in cytokeratin, organized as a filamentous network. In granular cells, the most abundant cells facing the urinary lumen, vasopressin promotes fusion of the membranous tubular structures located in the luminal cytoplasm with the apical cell membrane. A role for intermediate filaments in the membrane rearrangements induced by vasopressin in these cells, is proposed.
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    FILAMIN AND MYOSIN ARE PRESENT IN THE SECRETORY POLE OF AMPHIBIAN OXYNTIC CELLS - AN IMMUNOFLUORESCENCE STUDY
    (1986) DABIKE, M; MUNIZAGA, A; KOENIG, CS
    The presence of a filamin-like protein in oxyntic cells was established by indirect immunofluorescence microscopy. The location of this protein and myosin was studied, using specific antibodies, on frozen sections and isolated cells. Antifilamin and antimyosin reacted strongly with the luminal cytoplasm of the cells. In resting oxyntic cells, filamin appeared organized as a reticular sheet in the apical border. In stimulated cells, the apical concentration of filamin decreased, and its distribution appeared rather diffuse. This immunoreactive band seems to correspond to the cytoplasmic region where actin microfilaments have been described previously. The changes in the apical concentration of filamin, induced by the onset of HCl secretion, correlate with the ultrastructural reorganization of the actin network that occurs during the secretory cycle. The use of antimyosin antibodies showed that this protein forms an apical peripheral ring in both resting and stimulated cells. No clear changes in the distribution of myosin, in relation to secretion, could be established by immunofluorescence. These findings, taken together with published morphological and biochemical evidence, suggest that a three-dimensional network composed of actin and filamin is present in the secretory pole of resting amphibian oxyntic cells. The hypothesis that gel-sol transitions play a role in the structural reorganization of the secretory pole of these cells is supported by the present results.
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    ISOLATION OF PEROXISOMES FROM FROZEN HUMAN LIVER SAMPLES
    (1992) ALVAREZ, A; HIDALGO, U; KAWADA, ME; MUNIZAGA, A; ZUNIGA, A; IBANEZ, L; KOENIG, CS; SANTOS, MJ