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Biomedical subjects

T Tsukada

Publications and source records attributed to T Tsukada.

At least 217 records · Page 12Linked to original sources
PubMed1987

Induction of ornithine decarboxylase activity in mouse tissues by phorbol ester is effectively blocked by methylglyoxal bis(butylamidinohydrazone).

Ornithine decarboxylase (ODC) was induced in the liver, lung and brain of the mouse injected intraperitoneally with 12-O-tetradecanoylphorbol 13-acetate (TPA), showing maximal enzyme activity four hours after the injection. The increase of ODC activity was due to the enhanced syntheses of mRNA and protein. The induction of ODC activity by TPA was specifically blocked by methylglyoxal bis(butylamidinohydrazone) (MGBB), a competitive inhibitor of ODC and S-adenosylmethionine decarboxylase, but not by the analog methylglyoxal bis(guanylhydrazone) (MGBG).

Animals↗
PubMed1987

Infection with human parvovirus (B19), aplasia of the bone marrow and a rash in hereditary spherocytosis.

Infection with human parvovirus (HPV) B19 was diagnosed in persons with hereditary spherocytosis during an outbreak of erythema infectiosum. A 10-year-old boy had an aplastic crisis of the bone marrow and a maculopapular rash. His mother also had an aplastic crisis, fever, rash and a transiently acellular marrow. Another boy had an aplastic crisis, leucopenia and fever, but did not have a rash. Aplastic crisis and a rash have rarely before been observed together and attributed to infection with HPV.

Adult↗
PubMed1987

Von Willebrand factor fragment in type IIA von Willebrand's disease: demonstration of two different forms of fragments.

A fast-migrating precipitin peak which showed a reaction of partial immunochemical identity with the major von Willebrand factor (vWf) component was detected by crossed immunoelectrophoresis in agarose gel in plasma but not in platelets from a patient with type IIA von Willebrand's disease (vWD). Another patient undergoing urokinase therapy had a vWf fragment in plasma which was antigenically cross-reactive with the major vWf component. When plasma from both patients was mixed and electrophoresed together in the first dimension, two fast-moving precipitin arcs were demonstrated in the second dimension. These data indicate that two different kinds of vWf fragments can be generated in vivo.

Electrophoresis, Agar Gel↗
PubMed1987

Correlative light and electron microscopic immunocytochemistry on the same section with colloidal gold.

Ultrastructural localization of growth hormone in rat anterior pituitary and of muscle-specific actin in rabbit arterial smooth muscle cells was accomplished with a post-embedment procedure using colloidal gold. Plastic sections (2 microns) were mounted on slides, deplasticized, immunostained with immunoglobulin-colloidal gold particles, re-embedded in Epon, and sectioned for electron microscopy. This procedure enabled light and electron microscopic localization of these intracellular antigens on the same section. Positive immunostaining was demonstrated with this procedure with a muscle-specific actin antibody which previously failed to localize antigenic sites by EM. The procedure described yielded staining of high specificity, with minimal background and well-preserved ultrastructure. This re-embedding technique is useful in situations where problems with post-embedding EM immunostaining exist and where correlative LM and EM immunostaining is essential.

Actins↗
PubMed1987

Short-term prednisolone for inducing seroconversion from hepatitis B e antigen to antibody along with clinical improvement in patients with chronic active hepatitis type B.

Short-term prednisolone therapy was instituted on 27 patients with chronic active hepatitis (CAH) type B, in an attempt to induce seroconversion from hepatitis B e antigen (HBeAg) to the corresponding antibody (anti-HBe). Patients with CAH received a four-week regimen of prednisolone with daily dosage tapering from 40 to 10 mg (total 700 mg). Within one year after the withdrawal of prednisolone, 19 (70%) lost HBeAg and 11 of them (41% of the total) developed anti-HBe, at rates significantly higher than 3 (12%) and 1 (4%) who spontaneously showed respective serological changes among 26 matched controls during one year (p less than 0.001). Within two years after the withdrawal, 21 (78%) lost HBeAg and 19 (70%) developed anti-HBe, in contrast to 6 (23%) and 2 (8%) of controls who showed respective changes during that period (p less than 0.001). Seroconversion to anti-HBe was invariably accompanied by clinical and biochemical improvements along with loss of DNA polymerase from circulation. Elevation in transaminase levels, reflecting the rebound of steroid withdrawal, always heralded and appeared to be required for the seroconversion, but serious aggravation of hepatitis was not encountered in any of the patients.

Adult↗
PubMed1987

Effects of nicorandil on the conductive coronary artery of the dog.

The effects of nicorandil (2-nicotinamidoethyl nitrate, SG-75) on the conductive coronary artery were studied and compared with the effects of nitroglycerin and nifedipine. In isolated perfused canine heart preparations with a support dog, nicorandil produced a decrease in the resistance of the conductive coronary artery at reduced perfusion pressures, whereas nitroglycerin had similar effects even at normal perfusion pressures. In anesthetized closed-chest dogs, nicorandil and nitroglycerin produced an increase in the diameter of the conductive coronary artery (nicorandil less than nitroglycerin). Nifedipine failed to produce dilatation of the conductive coronary artery in both preparations. In isolated ring preparations of conductive coronary artery, all three compounds produced relaxation of the potassium-induced contracture, but only nicorandil and nitroglycerin reversed the lanthanum-induced contracture.

Animals↗
PubMed1987

Clinical and electrophysiological features of tilted disc syndrome.

Nine patients with tilted disc syndrome were examined psychophysically and electrophysiologically. Visual field defects did not correspond to fundus abnormalities in half of the eyes. Visual evoked responses were more reduced than electroretinogram responses. These results indicate that associated visual field defects and impairment of visual acuity were related not only to a localized staphylomatous ectasia of the posterior globe but also to a lesion of the inner retinal layer, optic nerve, or more proximal visual pathway. This suggests that a developmental abnormality in the embryonic retina may result in hypoplasia of the retinal pigment epithelium and neural elements as well as an anomaly of the optic disc. Investigation of visual function in patients with tilted disc syndrome may help to identify possible concomitant retinal and optic nerve dysfunction.

Adolescent↗
PubMed1987

HHF35, a muscle-actin-specific monoclonal antibody. I. Immunocytochemical and biochemical characterization.

A monoclonal antibody to muscle cell actin isotypes was produced and characterized. Immunocytochemical analysis of methanol-Carnoy's-fixed, paraffin-embedded human tissue revealed that this antibody, termed HHF35, reacts with skeletal muscle cells, cardiac muscle cells, smooth muscle cells, pericytes, and myoepithelial cells, but is nonreactive with endothelial, epithelial, neural, or connective tissue cells. When assayed by indirect immunofluorescence, HHF35 reacts with microfilament bundles from various cultured mammalian smooth muscle cells, but does not react with cultured human dermal fibroblasts or various epithelial tumor cell lines. In one-dimensional gel electrophoresis immunoblot experiments this antibody detects a 42-kd polypeptide from tissue extracts of uterus, ileum, aorta, diaphragm, and heart and extract from smooth muscle cells. The antibody also reacts with a comigrating 42-kd band of highly purified rabbit skeletal muscle actin. HHF35 is nonreactive on immunoblots of extracts from all tested nonmuscle cell extracts. Immunoelectrophoresis followed by immunoblotting performed in the presence of urea and reducing agents reveals recognition of the alpha isoelectrophoretic variant of actin from skeletal, cardiac, and smooth muscle sources and of the gamma variant from smooth muscle sources. Because HHF35 reacts with virtually all muscle cells, it will be useful as a marker for muscle and muscle-derived cells.

Actins↗
PubMed1987

HHF35, a muscle actin-specific monoclonal antibody. II. Reactivity in normal, reactive, and neoplastic human tissues.

Monoclonal antibody HHF35 has previously been characterized biochemically as recognizing isotypes of actin (alpha and gamma) which are specific to muscle cells. In this study, the authors have investigated the normal and pathologic tissue distribution of HHF35-positive cells using the avidin-biotin immunoperoxidase method on methacarn-fixed, paraffin-embedded sections of human tissue. In addition to muscle tissues (smooth, skeletal, and cardiac) the antibody localizes to myoepithelium, as well as most of the capsular cells of several parenchymal organs, including liver, kidney, and spleen, with extension of the latter cells into the splenic trabeculaes. In pathologic tissues, the antibody localizes to cells, identified by some investigators as "myofibroblasts," in the stroma of certain tumors, within hyperplastic fibrous tissue responses ("fibromatoses") such as Dupuytren's contracture, and within fibrotic lung tissue. HHF35 also localizes to cells that proliferate within the intima in lesions of atherosclerosis and to a unique population of reactive mesothelial and submesothelial cells. Among tumors, it is positive only on leiomyomas, leiomyosarcomas, and rhabdomyosarcomas, and negative on all nonmuscle sarcomas. This antibody thus shows great potential utility as a diagnostic reagent in various pathologic conditions, most especially in the diagnosis of tumors of muscle origin.

Actins↗
PubMed1986

Synthesis of N-chlorosulfonyl dicyclohexylamine as a potent inhibitor for spermidine synthase and its effects on human leukemia Molt4B cells.

N-Chlorosulfonyl dicyclohexylamine (CSD) was synthesized as a potent inhibitor of spermidine synthase and analyzed for antiproliferative effects on leukemic cells. The compound specifically inhibited spermidine synthase in a competitive mode with the substrate putrescine (Ki, 1.8 X 10(-7) M). When human leukemia Molt4B cells were cultured in the presence of the inhibitor, the intracellular level of spermidine and the rate of cell proliferation were markedly depressed. In these polyamine depleted and growth retarded cells the synthesis of protein, but not of DNA or RNA, was found to be significantly diminished.

Cell Division↗
PubMed1986

Ornithine decarboxylase and spermidine/spermine N1-acetyltransferase are induced in K562 cells by S-adenosylmethionine decarboxylase inhibitor methylglyoxal bis(guanylhydrazone) but not by analogous methylglyoxal bis(butylamidinohydrazone).

The activities of ornithine decarboxylase (ODC) and spermidine/spermine N1-acetyltransferase (SAT) were increased by the addition of S-adenosylmethionine decarboxylase (AdoMetDC) inhibitor methylglyoxal bis(guanylhydrazone) (MGBG) in cultured human erythroid leukemia K 562 cells. ODC activity began to increase 4 hr after the addition of the drug and attained a maximum at 12 hr. The increase of SAT activity lagged behind that of ODC activity. The increases of both ODC and SAT activities produced by MGBG were blocked by treatment with cycloheximide, suggesting that the increase of enzyme activity resulted from the synthesis of new enzyme proteins. The putrescine content in cells treated with MGBG increased markedly, whereas the levels of spermidine and spermine were depressed lower. On the other hand, methylglyoxal bis(butylamidinohydrazone) (MGBB), a derivative of MGBG inhibiting AdoMetDC effectively, did not induce ODC or SAT activities.

Acetyltransferases↗
PubMed1986

Hydrolysis of conjugated steroids by beta-glucuronidase from Ampullaria and application to the determination of urinary 17-hydroxycorticosteroids.

The usefulness of Ampullaria beta-glucuronidase as a reagent for the hydrolysis of steroid glucuronides was examined. The purified enzyme showed an optimum pH of 4, and was stable between pH 4.5 and 7.5. The enzyme from Ampullaria and Helix pomatia hydrolyzed various artificial substrates and conjugated steroids. Affinity of the Ampullaria enzyme for 17-hydroxycorticosteroid glucuronide was 7-fold the affinity of the Helix pomatia enzyme. Hydrolysis of urinary steroid conjugates was completed by an incubation with 320 Fishman units of Ampullaria beta-glucuronidase at 60 degrees C for 1 h. A close correlation was obtained between the values of steroid conjugates hydrolyzed by the Ampullaria enzyme and those by the bovine liver enzyme used conventionally. Ampullaria beta-glucuronidase is suitable for hydrolysis of urinary steroid conjugates because of its higher affinity for steroid substrate and the thermal stability.

17-Hydroxycorticosteroids↗
PubMed1986

Arachidonate 5-lipoxygenase inhibitors show potent antiproliferative effects on human leukemia cell lines.

Cirsiliol and AA861, specific arachidonate 5-lipoxygenase inhibitors, showed potent antiproliferative effects on human leukemic cell lines K562, Molt4B and HL60. On the other hand, HeLa cells were not affected by these drugs. In the inhibitor treated and growth retarded leukemia cells, the rates of synthesis of DNA, RNA and protein were markedly decreased. These results suggested that arachidonate 5-lipoxygenase or leukotrienes would play essential roles in cellular functions of leukemic cells.

Arachidonate Lipoxygenases↗