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Biomedical subjects

K Takazawa

Publications and source records attributed to K Takazawa.

At least 73 records · Page 4Linked to original sources
PubMed1991

Autologous blood transfusion with recombinant human erythropoietin in heart operations.

The effects of recombinant human erythropoietin (rHuEPO) on improving the anemia associated with autologous blood collection before open heart operations and on improving the postoperative anemia were studied. The study was carried out on 18 patients undergoing coronary artery bypass operations; 400 mL of autologous whole blood was taken from each patient 2 weeks before operation and was subsequently used in the operation, and rHuEPO (100 U.kg-1.day-1) was given intravenously for 2 weeks before operation and for 1 week after operation. The group in which iron preparations were also administered intravenously was designated as group I (10 patients), and the group in which rHuEPO was given alone was designated as group II (8 patients). In group III, as a control group, 11 past patients were used in whom 400 mL of autologous whole blood was collected 2 weeks before operation but neither rHuEPO nor iron preparations were given. After autologous blood collections, the hemoglobin levels improved in group I, group II, and group III, in that order, and with significant differences among them. It was shown that rHuEPO was effective in ameliorating the anemia associated with preoperative autologous blood collection, and the effect was further enhanced with intravenous supplementing iron preparations. After operation, the anemia markedly improved while rHuEPO was administered, but the hemoglobin levels decreased rapidly when the administration was terminated. Further studies are needed regarding the use of rHuEPO after operation.

Aged↗
PubMed1991

Inositol 1,4,5-trisphosphate 3-kinase mRNA: high levels in the rat hippocampal CA1 pyramidal and dentate gyrus granule cells and in cerebellar Purkinje cells.

The distribution of inositol 1,4,5-trisphosphate (InsP3) 3-kinase mRNA in the rat brain is reported using oligonucleotides based on a cDNA clone sequence that encodes rat brain InsP3 3-kinase and the in situ hybridization technique. Moderate levels were found in CA2-4 pyramidal neurons, in the cortex, and in the striatum. The cerebellar granule cells, thalamus, hypothalamus, brainstem, spinal cord, and white matter tracts were almost negative. The levels of InsP3 3-kinase mRNA were highest in the hippocampal CA1 pyramidal neurons, granule cells of the dentate gyrus, and cerebellar Purkinje cells. These results contrast with the lower concentration of the InsP3 receptor already reported in the hippocampus versus the Purkinje cells and suggest a special role for inositol 1,3,4,5-tetrakisphosphate in Ammon's horn.

Animals↗
PubMed1991

[The effects of coronary revascularization in patients with severe left ventricular dysfunction].

To evaluate the operative risk of coronary diseased patients who had severe left ventricular dysfunction, we retrospectively reviewed the cases of 798 patients who had received A-C bypass surgery at Juntendo University between Jan. 1984 and Dec. 1989. The patients with severe left ventricular dysfunction (Ejection Fraction less than 30%) (Group-A, n = 9) were compared with the patients with moderately impaired left ventricular function (E.F. 30%-40%) (Group-B, n = 28) and normal left ventricular function (E.F. greater than or equal to 50%) (Group C, n = 34). The mean E.F. were 21.56 +/- 3.72% in Group-A, 34.28 +/- 3.17% in Group-B, 64.19 +/- 12.02% in Group-C. There were no differences between the 3 groups with regard to Cardiac Index, LVEDP, number of diseased vessels, number of grafts, aortic cross clamp time and cardio-pulmonary bypass time. The percentages of patient who needed catecholamines support in postoperatively were 77.8% in Group-A, 46.4% in Group-B and 61.8% in Group-C. There were no operative and hospital deaths in each of the 3 Groups, whereas 2 patients of Group-A died later of noncardiac disease. We propose that patients with severe left ventricular dysfunction (15 less than or equal to EF, less than 30%) benefit from CABG surgery with low risk, and that each left ventricular E.F., Cardiac Index or LVEDP alone were less significant predictors of operative results as measured by preoperative left ventricular function.

Adult↗
PubMed1990

Cloning and expression in Escherichia coli of a rat brain cDNA encoding a Ca2+/calmodulin-sensitive inositol 1,4,5-trisphosphate 3-kinase.

Inositol 1,4,5-trisphosphate (InsP3) 3-kinase catalyses the phosphorylation of InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). InsP3 3-kinase activity was stimulated by Ca2+ in the presence of calmodulin (CaM) and the protein was associated with two silver-stained bands which migrated with an apparent Mr of approx. 50,000 on SDS/polyacrylamide gels. Upon limited proteolysis with trypsin, the native InsP3 3-kinase was converted into polypeptides of Mr 44,000 and 36,000. Both tryptic fragments displayed InsP3 3-kinase activity that was Ca2+/CaM-sensitive. A cDNA clone, C5, that encodes the C-terminal part of the InsP3 3-kinase, was isolated by immunoscreening of a rat brain cDNA library. The 5' end of this clone was used in turn to probe the same library, yielding a clone (CP16) containing the entire coding sequence of InsP3 3-kinase. The encoding protein of 459 amino acids (calculated Mr 50,868) has several putative phosphorylation sites for cyclic AMP-dependent protein kinase, protein kinase C and CaM-dependent protein kinase II. When clone C5 was expressed in Escherichia coli, the truncated fusion protein showed Ca2+/CaM-sensitive InsP3 3-kinase activity. Our data demonstrate that the N-terminal part of the protein is not essential for either enzymic or CaM-regulatory properties.

Amino Acid Sequence↗
PubMed1990

Rat brain inositol 1,4,5-trisphosphate 3-kinase. Ca2(+)-sensitivity, purification and antibody production.

Inositol 1,4,5-trisphosphate (InsP3) 3-kinase catalyses the ATP-dependent phosphorylation of InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). InsP3 3-kinase was purified from rat brain by Blue-Sepharose, phosphocellulose and calmodulin (CaM)-Sepharose affinity chromatography. The purified enzyme was stimulated by Ca2+/CaM by 3-6-fold as compared with the activity measured in the presence of EGTA. Rat brain InsP3 3-kinase activity was associated with two silver-stained bands of about equal activity which migrated with an apparent Mr of 50,000 on SDS/polyacrylamide gels. InsP3 3-kinase activity from rat brain could be immunoprecipitated by an antiserum against the SDS/PAGE-purified 50,000-Mr protein doublet. InsP3 kinase activity from bovine brain and the InsP3 5-phosphatase activity from rat brain were not immunoprecipitated. On Western blot, the human brain crude InsP3 3-kinase reacted specifically, but less strongly than the rat brain enzyme, with the antiserum.

Animals↗
PubMed1990

T4-thyroid storm after CT-scan with iodinated contrast medium.

A 62-year-old woman had thyroid storm 5 h after a CT examination (contrast enhancement with 65% meglumine amidotrizoate, Angiografin). At the time of admission to our hospital, serum T4 and serum free T4 levels were markedly elevated (29 micrograms/dl and 9.6 ng/dl, respectively); serum T3 and serum free T3 levels were within normal limits (144 ng/dl and 5.9 pg/ml, respectively). These findings suggest that thyroid storm can occur with excess T4 only (T4-thyroid storm), and that T4-thyroid storm can be caused by administration of iodinated contrast medium.

Diatrizoate Meglumine↗
PubMed1989

Stimulation of generation of inositol phosphates by carbamoylcholine and its inhibition by phorbol esters and iodide in dog thyroid cells.

The action of carbamoylcholine (Cchol), NaF and other agonists on the generation of inositol phosphates (IPs) was studied in dog thyroid slices prelabelled with myo-[2-3H]inositol. The stimulation by Cchol (0.1 microM-0.1 mM) of IPs accumulation through activation of a muscarinic receptor [Graff, Mockel, Laurent, Erneux & Dumont (1987) FEBS Lett. 210, 204-210] was pertussis- and cholera-toxin insensitive. Ins(1,4,5)P3, Ins(1,3,4)P3 and InsP4 were generated. NaF (5-20 mM) also increased IPs generation (Graff et al., 1987); this effect was potentiated by AlCl3 (10 microM) and unaffected by pertussis toxin. Although phorbol dibutyrate (5 microM) abolished the cholinergic stimulation of IPs generation (Graff et al., 1987), it did not affect the fluoride-induced response. Cchol and NaF did not require extracellular Ca2+ to exert their effect, and neither KCl-induced membrane depolarization nor ionophore A23187 (10 microM) had any influence on basal IPs levels, or on cholinergic stimulation. However, more stringent Ca2+ depletion with EGTA (0.1 or 1 mM) decreased basal IPs levels as well as the amplitude of the stimulation by Cchol without abolishing it. Dibutyryl cyclic AMP, forskolin, cholera toxin and prostaglandin E1 had no effect on basal IPs levels and did not decrease the response to Cchol. Iodide (4 or 40 microM) also strongly decreased the cholinergic action on IPs, this inhibition being relieved by methimazole (1 mM). Our data suggest that Cchol activates a phospholipase C hydrolysing PtdIns(4,5)P2 in the dog thyroid cell in a cyclic AMP-independent manner. This activation requires no extracellular Ca2+ and depends on a GTP-binding protein insensitive to both cholera toxin and requires no extracellular Ca2+ and depends on a GTP-binding protein insensitive to both cholera toxin and pertussis toxin. The data are consistent with a rapid metabolism of Ins(1,4,5)P3 to Ins(1,3,4)P3 via the Ins(1,4,5)P3 3-kinase pathway, followed by dephosphorylation by a 5-phosphomonoesterase. Indeed, a Ca2+-sensitive InsP3 3-kinase activity was demonstrated in tissue homogenate. Stimulation of protein kinase C and an organified form of iodine inhibit the Cchol-induced IPs generation. The negative feedback of activated protein kinase C could be exerted at the level of the receptor or of the receptor-G-protein interaction.

Aluminum↗
PubMed1989

Purification of bovine brain inositol 1,4,5-trisphosphate 3-kinase. Identification of the enzyme by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis.

Inositol 1,4,5-trisphosphate (InsP3) 3-kinase catalyses the ATP-dependent phosphorylation of InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). A method is presented for the rapid purification of InsP3 3-kinase from bovine brain by calmodulin (CaM)-Sepharose affinity chromatography. Maximal activation of the purified InsP3 3-kinase by Ca2+/CaM was 6-7-fold as compared with the activity measured in the presence of EGTA (1 mM) and 10 microM-InsP3. At 10 microM-InsP3 and 0.1 mM free Ca2+, half-maximal activation required about 2 nM-CaM. The mechanism of activation by CaM appeared to be an increase in the maximal velocity of the enzyme without a substantial change in the Km for InsP3. Further purification was achieved by phosphocellulose chromatography eluted with ATP. Specific activity of the purified enzyme at 37 degrees C and 10 microM-InsP3 was 10-20 mumol/min per mg. The apparent Mr of the enzyme, determined by f.p.l.c.-gel filtration, was estimated as about 44,000. The purified InsP3 3-kinase was subjected to SDS/10%-polyacrylamide-gel electrophoresis. InsP3 3-kinase activity was associated with three silver-stained bands, which migrated with apparent Mr values of approx. 52,000, 38,000 and 35,000.

Animals↗
PubMed1989

Localized myxedema on the nasal dorsum in a patient with Graves' disease: report of a case.

We report the case of a 56-year-old Japanese female with Graves' disease associated with localized myxedema on the nasal dorsum. The patient developed localized myxedema concomitantly with hyperthyroidism before antithyroid therapy was given. The lesion was totally removed surgically, as it was small and well circumscribed. Although unusual locations of localized myxedema have been reported elsewhere, there is to date no case of localized myxedema on the nasal dorsum without involvement of the pretibial area reported in the literature. We discuss this unique feature of our patient.

Autoantibodies↗
PubMed1988

Ca2+/calmodulin-sensitive inositol 1,4,5-trisphosphate 3-kinase in rat and bovine brain tissues.

Inositol 1,4,5-trisphosphate (Ins P3) 3-kinase catalyzes the ATP-dependent phosphorylation of Ins P3 to Inositol 1,3,4,5-tetrakisphosphate (Ins P4). Ca2+/calmodulin (CaM)-sensitivity of Ins P3 3-kinase was measured in the crude soluble fraction from rat brain and different anatomic regions of bovine brain. Kinase activity was inhibited in the presence of EGTA (free Ca2+ below 1 nM) as compared to Ca2+ (10 microM free Ca2+) or Ca2+ (10 microM free Ca2+) and CaM (1 microM). Ca2+-sensitivity was also seen for the cAMP phosphodiesterase measured under the same assay conditions, but was not for the Ins P3 5-phosphatase. DEAE-cellulose chromatography of the soluble fraction of rat brain or bovine cerebellum resolved a Ca2+/CaM-sensitive Ins P3 3-kinase (maximal stimulation at 1 microM Ins P3 substrate level was 2.0-3.0 fold).

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

Phagocytotic activities of latex beads by FRTL cell: possible interaction of cell surface glycoprotein.

We investigated the phagocytic activity of cultured rat thyroid cells (FRTL) by using latex beads. FRTL cells ingested many carboxylate-modified polystyrene latex beads (c-latex beads), which had carboxyl residues on the surface, whereas they ingested few polystyrene latex beads (p-latex beads), which had no electrostatic charge. Phagocytotic activity of c-latex beads was stimulated by TSH in a dose-related manner. Dibutyryl, 8-bromo-cAMP, and forskolin also stimulated this process. Tunicamycin significantly inhibited dibutyryl cAMP-stimulated phagocytotic activity of c-latex beads by FRTL cells. N-acetylglucosaminidase also inhibited dibutyryl cAMP-stimulated phagocytosis. These results suggest that the interaction between negative surface charge of c-latex beads and positive surface charge probably induced by N-acetylglucosamine in the cell surface glycoprotein, might play an important role in the phagocytosis of FRTL cells.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1987

The inhibitory effects of calmodulin antagonists on TSH-stimulated thyroid hormone release by mouse thyroid lobes.

Calcium ions have been shown to play a mojor regulatory role in the release of various hormones from a wide variety of endocrine organs. More recently, in vitro evidence suggests that a calcium-binding protein, calmodulin, is also involved in the release of many hormones. So we examined the effects of several types of calmodulin antagonists on TSH-stimulated thyroid hormone release in vitro. Mouse thyroid lobes (one thyro-tracheal unit/tube) were incubated in Krebs-Ringer bicarbonate buffer at 37 degrees C for 4h. Free thyroxine (fT4) released in the incubation medium, thyroidal cAMP and calmodulin content were measured by RIA. TSH (5 mU/ml) and dibutyryl cAMP (DBC) (200 micrograms/ml) caused a 2-4 fold increase in thyroidal release of fT4. The stimulatory effects of TSH on fT4 release were significantly inhibited by trifluoprazine and prenylamine lactate at the concentration of 5 X 10(-5) M. More specific calmodulin antagonists, W-7 and W-13, were also shown to inhibit TSH stimulation of fT4 release at the concentration of 5 X 10(-5) M. In contrast, TSH stimulation of fT4 release was not depressed by non-specific antagonists, W-5 or W-12, at the same concentration as 5 X 10(-5) M. Further, W-13 also markedly inhibited DBC-stimulated fT4 release. Neither TSH nor PGI2 altered the thyroidal calmodulin content, dissociating with a marked increase in the cAMP concentration. These results suggest that calmodulin plays an important role in TSH-stimulated thyroid hormone release and further that this mechanism exists, at least in part, at the site subsequent to the generation of cAMP.

Animals↗
PubMed1986

Immunochemical and immunohistochemical localization of parvalbumin in rat nervous tissues.

The contents of parvalbumin in various nervous tissues of the rat were measured by radioimmunoassay (RIA) and its cellular distribution was immunohistochemically examined by peroxidase-antiperoxidase methods. The antibody, raised in rabbits using rat skeletal muscle parvalbumin, did not cross-react with other Ca2+-binding proteins such as calmodulin or S-100 proteins. The RIA demonstrated the wide distribution of the antigen, with very high levels in the cerebellum (3,217 +/- 519 ng/mg protein). The immunohistochemical description by Celio and Heizmann [Nature 293, 300-302 (1981)] was confirmed concerning the existence of the antigen in Purkinje cells of the cerebellum; nonpyramidal neurons of the cerebral cortex; and medium-sized cells of the olfactory bulb, hippocampus, and reticular nucleus of the thalamus. In addition to these neurons, we found the parvalbumin-like immunoreactivity in the large neurons of the superior vestibular nucleus and the neurons of the medial superior olive nucleus. In the gamma-aminobutyric acid (GABA)-containing nuclei such as substantia nigra, caudatoputamen, and globus pallidus, parvalbumin-positive cells and fibers were rare. In the medial lemniscus of the midbrain which contains no GABA, parvalbumin-immunoreactive fibers were prominent. The possibility was discussed that parvalbumin exists in a specific population of neurons that differ from those containing GABA.

Animals↗