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Biomedical subjects

K Ikai

Publications and source records attributed to K Ikai.

At least 91 records · Page 5Linked to original sources
PubMed1985

[The ureteral stent: is it useful?].

Double-J or double-pigtail ureteral stent was used in 7 cases, 6 cases for ureteral obstruction and 1 case for ureterocutaneous fistula in irradiated patients. In 5 cases ureteral stent failed to drain effectively, in 4 of these 5 cases due to stent obstruction by necrotic tissue which led to percutaneous nephrostomy in 3 cases. In 1 case the ureteral stent drained well and in another case effectiveness of ureteral stent was equivocal. We think that ureteral stent is neither safe nor effective for internal divertion except in short term use postoperatively.

Adult↗
PubMed1984

Prostaglandin D2 and prostaglandin D synthetase in mast cell deficient mice.

The content of prostaglandin D2 (PGD2) and the activity of PGD synthetase were measured in various tissues of mutant mice deficient in tissue mast cells (W/Wv) and congenic normal mice (+/+). The amounts of PGD2 were determined by the radioimmunoassay specific for PGD2. PGD2 was found in all tested tissues including brain, lung, stomach, spleen and skin of both genotypes in concentrations of a few to about thirty ng/g wet weight tissue, and in spite of the absence of tissue mast cells and the very low content of tissue histamine in W/Wv mice, there was no difference in tissue PGD2 amounts between W/Wv and +/+ mice. The activity of PGD synthetase was assayed in supernatant fraction (10,000 X g, 20 min) of tissue homogenates in the presence or absence of 1 mM GSH. All the tissues of both genotypes listed above showed considerable activity of PGD synthetase, and no difference in tissue PGD synthetase activity was found between W/Wv and +/+ mice. These results suggest that mast cells contribute little to the total amount of PGD2 and PGD synthetase activity in various tissues of mice, and that tissues can synthesize PGD2 independently of tissue mast cells.

Animals↗
PubMed1984

Induction of murine teratocarcinoma cell differentiation by suppression of poly(ADP-ribose) synthesis.

Poly(ADP-ribose) synthesizing activity in mouse teratocarcinoma EC-A1 cells decreased markedly during differentiation induced by retinoic acid; the activities assayed in permeabilized cells decreased to 25% and 10% of the activity of control (uninduced cells) 2 and 3 days, respectively, after the addition of 0.1 microM retinoic acid to the culture medium. This change preceded changes in morphology and DNA synthesis, which became prominent after 4 days. The decrease in poly(ADP-ribose) synthesizing activity appeared to be caused by a diminution of the synthetase protein and not by a decrease in its catalytic activity, because the full activity disclosed by DNase I treatment decreased in parallel, albeit at about 20 times higher levels. When 8 mM 3-aminobenzamide or 10 mM nicotinamide, specific inhibitors of poly(ADP-ribose) synthetase, was added to the culture medium, the cells underwent differentiation after 7-9 days. An analogue, 3-aminobenzoic acid, which is not inhibitory to the synthetase, induced differentiation much less efficiently than did 3-aminobenzamide, and the effect of 3-aminobenzoic acid appeared to be ascribable to its potent cytotoxicity. Immunohistochemical analysis using anti-poly(ADP-ribose) antibody confirmed the marked reduction in poly(ADP-ribose) synthesizing activity in nuclei of the cells treated with retinoic acid or 3-aminobenzamide but not with 3-aminobenzoic acid. These results suggest that a decrease in poly(ADP-ribose) synthesis triggers differentiation of teratocarcinoma cells.

Aminobenzoates↗
PubMed1983

Phosphorylation of keratin polypeptides.

The phosphorylation of keratin polypeptides was examined in calf snout epidermis. When slices of epidermis were incubated in the medium containing 32Pi, the radioactivity was incorporated into several proteins. The predominant phosphorylated proteins migrated in SDS-polyacrylamide gels with apparent molecular weights between 49000 and 69000 and coincided with keratin polypeptides. The extent of keratin phosphorylation was not altered in the presence of dibutyryl cyclic AMP or reagents which elevate intracellular cyclic AMP. When homogenates of epidermis were incubated with [gamma-32P]ATP, keratin polypeptides were the predominant species phosphorylated as was also observed in epidermal slices. The presence of cyclic AMP or heat-stable inhibitor of cyclic AMP-dependent protein kinase in the reaction mixture did not affect the phosphorylation of keratin polypeptides, although the phosphorylation of exogenously-added histone was stimulated and inhibited, respectively, by these additions. Keratin polypeptides extracted from calf snout epidermis by 8 M urea were phosphorylated by incubation with [gamma-32P]ATP and cyclic AMP-dependent protein kinase from calf snout epidermis or bovine heart. No proteins were phosphorylated without the addition of the enzymes. The presence of cyclic AMP in the reaction mixture stimulated the keratin phosphorylation, and further addition of heat-stable protein kinase inhibitor reduced this stimulation.

Animals↗
PubMed1983

Distribution patterns of cytoplasmic microtubules in epidermal keratinocytes.

The distribution of cytoplasmic microtubules in cultured guinea-pig keratinocytes was investigated using immunofluorescence (IF) microscopy with monospecific anti-tubulin antibodies and electron microscopy (EM). In culture, adherent cells displayed networks of thin fluorescent fibres, while a homogeneous and/or granular cytoplasmic IF was shown in the cells of upper layers as well as in trypsinized cells. By EM many microtubules were shown in adherent cells but there were fewer or none in the upper layers. An increase in calcium ion (Ca2+) concentration and the addition of an ionophore (X537A) to the culture medium caused disassembly of microtubules. This effect was cancelled by a calmodulin inhibitor. Cryostat sections of normal human and guinea-pig epidermis stained with anti-tubulin antibodies showed a homogeneous and/or granular cytoplasmic IF from basal to granular layers but no detectable IF was seen in the horny layer. These results suggest that keratinocytes contain a cellular pool of tubulin in various states of polymerization and that microtubule disassembly may occur during differentiation, probably being regulated by Ca2+-calmodulin complexes.

Animals↗
PubMed1983

Immunohistochemical demonstration of poly(adenosine diphosphate-ribose) synthetase in bovine tissues.

The inter- and intracellular localization of poly(adenosine diphosphate-ribose)(poly(ADP-ribose] synthetase was investigated using an indirect immunofluorescence technique and a specific antibody against the enzyme purified from calf thymus. In various bovine tissues, including liver, heart, pancrease, thyroid, spleen, adrenal, and skeletal muscle, the specific immunofluorescence of poly(ADP-ribose) synthetase was localized exclusively in the nucleus. Immunostaining was inhibited by preabsorption of the antibody with purified calf thymus poly(ADP-ribose) synthetase. Nuclear immunofluorescence appeared to be more prominent in the marginal area than in the central region in most nuclei. This staining pattern is similar to that of naturally occurring poly(ADP-ribose). In bovine peripheral blood the immunofluorescence of poly(ADP-ribose) synthetase was detected in nuclei of lymphocytes, but not in granulocytes, in agreement with the finding that the enzymatic activity of poly(ADP-ribose) synthetase was barely detectable in nuclei isolated from granulocytes.

Animals↗
PubMed1981

Poly(ADP-ribose) synthesis in human cervical cancer cell-diagnostic cytological usefulness.

Poly(ADP-ribose) synthetase activity in human cervical cancer cell nuclei was found to be approximately twice that of normal cervical cell nuclei. Using antipoly(ADP-ribose) antibody, frozen section of normal tissue were stained by indirect-immunofluorescence and it was demonstrated that the fluorescence of nuclei in squamous cells decreased during maturation. Correspondingly, superficial cells appearing in smear specimens had less nuclear fluorescence compared with parabasal cells in the same smear. However, cancer cells in cervical smears had marked nuclear fluorescence using immunostaining and were easily distinguished from normal cells.

Cell Nucleus↗
PubMed1980

Poly(ADP-ribose) synthesis, a marker of granulocyte differentiation.

By using an indirect immunofluorescence technique, the distribution of poly(ADP-ribose) synthesis in human blood cells was investigated. The antibody used was reactive with poly(ADP-ribose) larger than trimers. The specific immunofluorescence of poly(ADP-ribose) synthesized in situ from NAD+ was observed in nuclei of lymphocytes and monocytes in normal peripheral blood. No immunofluorescence, however, was detected in granulocytes and erythrocytes. In agreement with this finding, no incorporation of radioactivity from [adenine-14C]NAD+ into acid-insoluble material was detectable in nuclei isolated from granulocytes. In normal bone marrow, the immunofluorescence of poly(ADP-ribose) was not observed in myelocytes or in their descendants but was observed in nuclei of lymphocytes and erythroblasts. Myelocytes and mature granulocytes in peripheral blood as well as in bone marrow of patients with chronic myelocytic leukemia were totally negative in the polymer-specific immunofluorescence. In marked contrast, prominent fluorescence was observed in nuclei of myeloblasts that appeared in peripheral blood as well as in bone marrow of patients with acute myeloblastic leukemia. Myeloblasts appearing in peripheral blood of patients in blastic crisis of chronic myelocytic leukemia also showed the nuclear immunofluorescence. These results suggest that the capacity for synthesizing poly(ADP-ribose) serves as a marker of differentiation of granulocytes, and its immunohistochemical analysis may be useful for differential diagnosis of leukemias, especially in blastic crisis.

Adenosine Diphosphate Ribose↗
PubMed1980

Immunohistochemical demonstration of poly(adenosine diphosphate-ribose) in nuclei of various rat tissues.

Natural distribution of poly(adenosine diphosphate-ribose), a novel macromolecule in eukaryotes, was investigated using an indirect immunofluorescence technique. The antibody, produced in a rabbit toward poly(ADP-ribose), was most reactive with polymers having the chain length of about 25 ADP-ribose units and weakly reactive with short oligomers; it was totally inert with monomers. Immunostaining with this antibody revealed the existence of the polymer in various rat tissues. The immunostaining seems to be specific for poly(ADP-ribose), as judged by its disappearance by preabsorption of the antiserum with purified poly(ADP-ribose) or pretreatment of tissue sections with poly(ADP-ribose)-degrading enzymes. Intensification of the fluorescence by preincubation with nicotinamide adenine dinucleotide (NAD), a substrate for poly(ADP-ribose) synthesis, also supported this view. The immunofluorescence of poly(ADP-ribose) was found exclusively in the nucleus of almost all tissues tested, including liver (adult, newborn, regenerating, and hepatoma), brain, heart, intestine, pancreas, kidney, spleen, testis, thyroid gland, and skeletal muscle. Exceptions were blood cells; little fluorescence was detectable in nuclei of peripheral leukocytes. Only after preincubation with NAD, did lymphocytes and monocytes exhibit fluorescence, however, granulocytes never did exhibit fluorescence. The cells appeared to represent the first instance where poly(ADP-ribose) synthesis activity among eukaryotic cells was missing.

Animals↗
PubMed1979

Morphaea-like cutaneous changes in a patient with systemic scleroderma.

A case of systemic scleroderma with peculiar morphaea-like lesions is reported. The patient at first started with typical acrosclerosis, some parts of which later became softened and apparently resumed the appearance of normal skin, so that morphaea-like cutaneous plaques which remained hard, were soft. These changes were surrounded by erythema resembling the 'lilac ring' as noted in characteristic active lesions of morphaea.

Female↗