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T Yoshimura

Publications and source records attributed to T Yoshimura.

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

Thermostable alanine racemase of Bacillus stearothermophilus: subunit dissociation and unfolding.

The guanidine hydrochloride-induced subunit dissociation and unfolding of thermostable alanine racemase from Bacillus stearothermophilus have been studied by circular dichroism, fluorescence and absorption spectroscopies, and gel filtration. The overall process was found to be reversible: more than 75% of the original activity was recovered upon reduction of the denaturant concentration. In the range of 0.6 to 1.5 M guanidine hydrochloride, the dimeric enzyme was dissociated into a monomeric form, which was catalytically inactive. The monomeric enzyme appeared to bind the cofactor pyridoxal phosphate by a non-covalent linkage, although the native dimeric enzyme binds the cofactor through an aldimine Schiff base linkage. The monomer was mostly unfolded, with the transition occurring in the range of 1.8 to 2.2 M guanidine hydrochloride.

Alanine Racemase↗
PubMed1991

Neutrophil recruitment by intradermally injected neutrophil attractant/activation protein-1.

Neutrophil attractant/activation protein-1 (NAP-1) is a recently described cytokine that attracts neutrophils, but not monocytes or eosinophils. This leukocyte specificity is not absolute, in that NAP-1 attracts basophils and small numbers of lymphocytes. Our purpose was to determine in vivo effects of NAP-1, and to compare them to the reported action of the complement attractant, C5a. Intradermal injection into normal human subjects of 40 microliters of NAP-1, over a concentration range of 4 x 10(-8) M to 10(-6) M, caused no symptoms or signs such as wheal-and-flare, itching, induration, or tenderness. However, biopsies of injection sites showed perivascular neutrophil infiltration as early as 30 min, which increased at 1 and 3 h. The mean number of neutrophils per mm2 of dermis for 15 biopsies taken 3 h after intradermal injection of 2 x 10(-7) M or 10(-6) M NAP-1 was 164 +/- 41; the response to saline or a NAP-1 inactive fragment was 5 or less. Intradermal NAP-1 did not cause basophil or lymphocyte infiltration. Consistent with the absence of a wheal-and-flare, acid toluidine blue-stained sections showed no evidence of mast cell degranulation, in contrast to previously reported results with C5a. Thus, the predominant response by human subjects to intradermal NAP-1 was neutrophil accumulation in proximity to dermal blood vessels.

Adolescent↗
PubMed1991

Distribution, purification, and characterization of thermostable phenylalanine dehydrogenase from thermophilic actinomycetes.

Phenylalanine dehydrogenase (L-phenylalanine:NAD oxidoreductase, deaminating; EC 1.4.1.-) was found in various thermophilic actinomycetes. We purified the enzyme to homogeneity from Thermoactinomyces intermedius IFO 14230 by heat treatment and by Red Sepharose 4B, DEAE-Toyopearl, Sepharose CL-4B, and Sephadex G-100 chromatographies with a 13% yield. The relative molecular weight of the native enzyme was estimated to be about 270,000 by gel filtration. The enzyme consists of six subunits identical in molecular weight (41,000) and is highly thermostable: it is not inactivated by incubation at pH 7.2 and 70 degrees C for at least 60 min or in the range of pH 5 to 10.8 at 50 degrees C for 10 min. The enzyme preferably acts on L-phenylalanine and its 2-oxo analog, phenylpyruvate, in the presence of NAD and NADH, respectively. Initial velocity and product inhibition studies showed that the oxidative deamination proceeds through a sequential ordered binary-ternary mechanism. The Km values for L-phenylalanine, NAD, phenylpyruvate, NADH, and ammonia were 0.22, 0.078, 0.045, 0.025, and 106 mM, respectively. The pro-S hydrogen at C-4 of the dihydronicotinamide ring of NADH was exclusively transferred to the substrate.

Actinomycetales↗
PubMed1991

The indirect association of human T-cell leukemia virus tax protein with DNA results in transcriptional activation.

trans-activator p40tax of human T-cell leukemia virus type I activates specific enhancers and stimulates transcription of the viral and some cellular genes but does not bind directly to the enhancer sequences. We demonstrated here that a fusion protein of p40tax and GAL4 DNA binding domain activated transcription dependent on the GAL4-binding site in the reporter plasmid. Mutants of p40tax were also tested in the fusion protein, and their activities were found to be in parallel with those of their free forms on the original target long terminal repeat. This activation with GAL4 fusion protein was interfered with by the free form of p40tax. These results suggest that p40tax associates with DNA through interaction with DNA binding protein(s) and also interacts with another transcription factor(s) to elicit the activation.

Blotting, Western↗
PubMed1991

Angiotensin II and alpha-agonist. III. In vitro fetal-maternal placental prostaglandins.

In fetal sheep, angiotensin II, but not phenylephrine, increases umbilical venous concentrations of prostaglandin E2 (PGE2) and prostacyclin (PGI2); however, their source(s) is unknown. We sought to determine the tissue source(s) of this increase in prostanoids and to compare responses in fetal and maternal tissues. Fetal placental arteries (PA) and veins (PV), mesenteric arteries (MA) and cotyledons, and maternal caruncles and uterine arteries (UA) from eight pregnant ewes [127 +/- 3 (SE) days] were incubated (37 degrees C, 1 h) in Krebs-Henseleit (95% O2-5% CO2) with or without angiotensin II, phenylephrine, or norepinephrine (5 x 10(-10) and 5 x 10(-8) M). Basal PGE2 production exceeded PGI2 in PA, cotyledons, and caruncles (P less than 0.05), whereas PGE2 less than PGI2 only in UA; production of both prostanoids was greatest in MA with 34.8 +/- 5.0 and 27.4 +/- 3.7 pg.micrograms protein-1.h-1, respectively (P less than 0.001). Caruncles produced little of either prostanoid. Angiotensin II increased PA PGE2 production from 6.5 +/- 1.5 to 8.4 +/- 3.0 and 10.8 +/- 4.5 pg.micrograms-1.h-1 (P = 0.001) and PGI2 from 3.3 +/- 0.5 to 5.5 +/- 1.5 (P less than 0.05) and 3.7 +/- 0.9 pg.micrograms-1.h-1; PV PGE2 rose from 4.5 +/- 1.1 to 9.0 +/- 3.5 and 7.9 +/- 2.3 pg.micrograms-1.h-1 (P less than 0.05); PV PGI2 was unchanged. Angiotensin II increased UA PGE2 from 1.5 +/- 0.3 to 3.4 +/- 1.2 (P less than 0.05) and 2.4 +/- 0.8 pg.micrograms-1.h-1 and PGI2 from 8.7 +/- 1.0 to 12.4 +/- 2.2 and 16.2 +/- 5.2 (P less than 0.05) pg.micrograms-1.h-1. Angiotensin II had no effect on MA, cotyledonary, or caruncular prostanoids. alpha-Agonist had no effect on any tissue examined. In fetal sheep, angiotensin II-induced increases in PGI2 and PGE2 are likely of vascular origin.

Angiotensin II↗
PubMed1991

Synthesis of lanosterol derivatives with a functional group at C-32, including an antineoplastic sterol, 3 beta-hydroxylanost-7-en-32-oic acid.

Lanosterol derivatives with a functional group at C-32 have been synthesized from 3 beta-acetoxylanostan-7 alpha-ol. The key reaction of the synthesis is the hypoiodite reaction of 3 beta-acetoxylanostan-7 alpha-ol. In vitro antitumor activity testing of the lanosterol derivatives revealed that 3 beta-hydroxylanost-7-en-32-oic acid has antineoplastic activity.

Animals↗
PubMed1991

A new anti-platelet drug, E5510, has multiple suppressive sites during receptor-mediated signal transduction in human platelets.

The mode of action of E5510, 4-cyano-5,5-bis(4-methoxyphenyl)-4-pentenoic acid, which has very potent anti-platelet activities, was investigated by examining its effects on the biochemical responses in the process of human platelet activation. In a whole-cell system, E5510 inhibited the increased turnover of inositol phospholipids arising from phospholipase C activation, arachidonic acid release from phospholipids by phospholipase A2, mobilization of intracellular free Ca2+, protein kinase C activation, and thromboxane A2 production. In a cell-free system, E5510 inhibited cyclooxygenase activity and cyclic AMP-dependent phosphodiesterase activity in a dose-dependent manner. An elevation of cyclic AMP in platelets was also observed at a relatively high concentration of E5510. It was suggested that receptor-mediated turnover of inositol phospholipids, intracellular Ca2+ increase, arachidonic acid release from phospholipids and protein kinase C activation might be indirectly inhibited by the increased cyclic AMP level in platelets. Thromboxane A2 production in the whole-cell system was very strongly inhibited by E5510, and the IC50 for this effect was 100 times lower than that of direct inhibition of cyclooxygenase in the cell-free system. It was concluded that although the primary mode of action of E5510 is the inhibition of the cyclooxygenase pathway of positive signal transduction in platelets, E5510 has another mode of action by increasing platelet cyclic AMP, which can act as a negative messenger in platelet signal transduction, and these multiple sites of action synergistically antagonize platelet cellular activation.

Arachidonic Acid↗
PubMed1991

Metabolism and excretion of a new 5-lipoxygenase inhibitor in rats, guinea-pigs, beagles and rhesus monkeys.

1. The 5-lipoxygenase inhibitor (I), a substituted benzothiazole is metabolized mainly by glucuronide and/or sulphate conjugation in rat, guinea-pig, beagle and rhesus monkey. Glucuronidation is the major pathway, and sulphation is more extensive in rat and beagle than in guinea-pig and rhesus monkey. 2. After a single oral dosing of 14C-I (10 mg/kg), more than 96% of the dose was excreted in 7 days in all four species, however there is species difference in urinary excretion, which was 2.8 +/- 0.3% in rat, 46.9 +/- 1.6% in guinea-pig, 2.6% in beagle and 68.2% in rhesus monkey. 3. After a single i.v. dose of 14C-I to bile duct-cannulated rats and guinea pigs, bile was a major route of elimination, and in rats the ratio of glucuronide to sulphate in excreta increased from 0.71 +/- 0.01 to 0.93 +/- 0.05 as the dose was increased from 0.2 to 20 mg/kg.

Animals↗
PubMed1991

Inhibitory effects of the novel platelet activating factor receptor antagonist, 1-ethyl-2-[N-(2-methoxy)benzoyl-N-[(2R)-2-methoxy-3-(4- octadecylcarbamoyloxy) piperidinocarbonyloxypropyloxy]carbonyl] aminomethyl-pyridinium chloride, in several experimentally induced shock models.

E5880 (1-ethyl-2-[N-(2-methoxy)benzoyl-N-[(2R)-2-methoxy-3-(4- octadecylcarbamoyloxy) piperidinocarbonyloxypropyloxy] carbonyl]aminomethylpyridinium chloride, CAS 128420-61-1) is a novel analog-type antagonist of platelet activating factor (PAF). This paper describes the in vitro PAF antagonistic activity of E5880 and its in vivo effect in various experimentally induced shock models. Inhibition by E5880 of [3H]platelet activating factor (PAF) binding to human platelet PAF receptor was extremely potent; its IC50 value was 0.27 nmol/l, so that it was about 5 times more potent than PAF itself. Its IC50 value in inhibition of washed human platelet aggregation induced by PAF was 0.66 nmol/l. Intravenous treatment with E5880 dose-dependently reversed PAF-induced hypotension in rats and protected mice from lethality caused by PAF. Lipopolysaccharide (LPS)-induced hypotension in rats was inhibited by both pre- and post-treatment with E5880. It was also confirmed that blood PAF level, measured by the GC-NICI-MS method, was increased after LPS challenge in this model. Furthermore, E5880 was extremely effective in preventing passive anaphylactic lethality in mice. Blood PAF level in this model was also increased immediately after antigen challenge, and this was coincident with the time at which signs of shock became apparent. These findings support the concept that PAF is an important mediator in the development of LPS-induced shock and anaphylactic shock, and suggest that E5880, a novel and potent PAF antagonist, may be effective in clinical treatment for shock states.

Animals↗
PubMed1991

[A case of Rothmann-Makai syndrome associated with mononeuropathy].

We reported the first case of Rothmann-Makai syndrome associated with mononeuropathy in a 31-year-old woman. In June 1989, she noticed several small subcutaneous nodules in the bilateral upper arms. On July 2, she woke up because of severe pain below the knee in the right leg which lasted 15 hours. On admission, subcutaneous nodules were recognized on bilateral upper arms, abdomen, gluteal regions and thighs. None of these nodules were associated with local heat or pain. Muscle weakness and dysesthesia were observed in the right foot, but deep tendon reflexes were normal. Electrophysiological studies revealed a decrease of the amplitude of action potential and of the conduction velocity in the right tibial nerve. Microscopic examination of skin biopsy showed lipolysis and diffuse lymphocyte infiltration (panniculitis) and perivascular lymphocyte infiltration was also observed. Routine laboratory data including peripheral blood, ESR, blood chemistry, and CRP were in the normal range and antinuclear antibodies and LE cells were not detected. By those findings, she was diagnosed as Rothmann-Makai syndrome associated with mononeuropathy. Steroid treatment was effective on both skin lesions and mononeuropathy. Steroid treatment was effective on both skin lesions and mononeuropathy. We concluded that this mononeuropathy may be induced by a ischemic change which may be caused by panniculitis.

Adult↗
PubMed1991

[A case of mixed connective tissue disease with subacute transverse myelopathy].

A rare case of mixed connective tissue disease (MCTD) with subacute transverse myelopathy and various neurological signs was reported. The patient, a 53 year-old woman, was admitted to our hospital with subacute progressive muscle weakness of left lower limb and sensory disturbance of bilateral lower extremities. At the age of 40, she suffered from sensory disturbance of her face, which improved in about three years. She had a high fever, Raynaud phenomenon, dyshydrosis on right side of her face at the age of 43. On the admission, physical examination revealed swollen fingers and telangiectasia of her face. Neurologically, she had transverse myelopathy at the level of Th6, bilateral trigeminal neuropathy, tonic, pupils, polyneuropathy and dyshydrosis. Laboratory examination showed positive antinuclear antibody, a high titer of antibody to RNase-sensitive components of extractable nuclear antigen, positive antinuclear RNP antibody and negative anti-Sm antibody. Her myelopathy improved with corticosteroid therapy, and ESR and the level of immunoglobulin were normalized. But, other neurological signs showed no improvement.

Cranial Nerve Diseases↗
PubMed1991

[A case of Crow-Fukase syndrome associated with idiopathic thrombocytopenic purpura].

A 40-year-old man was admitted to our hospital because of paresthesia and weakness of the limbs. At the age of 38, he was diagnosed as having an idiopathic thrombocytopenic purpura (ITP) which have been refractory to oral administration of prednisolone and splenectomy. Platelet-associated IgG was elevated markedly at that time. It was, however, only mildly elevated on this admission. He showed polyneuritis, generalized pigmentation, hirsutism, and marked edema on the legs. The bone X-ray disclosed a lytic lesion in the left iliac bone, which was confirmed as a plasmacytoma by bone biopsy. Axonal degeneration with marked loss of myelinated figure was seen on sural nerve biopsy. Serum immunoelectrophoresis revealed his monoclonal IgG was lambda type. Then, he was diagnosed as having a Crow-Fukase syndrome associated with ITP. Plasma exchange, pulse therapy, and irradiation to plasmacytoma resulted in a slight improvement of the polyneuritis and the skin symptoms, and a disappearance of edema. However, ITP has not responded to these therapies. Although the same autoimmune mechanism is suggested in these conditions, we could not clarify how this monoclonal IgG produce both polyneuritis and ITP.

Adult↗
PubMed1991

Characterization of the half and overall reactions catalyzed by L-lysine:2-oxoglutarate 6-aminotransferase.

Significant differences were found in the reaction rate, and the substrate and reaction specificities between the half reactions and the overall reactions catalyzed by L-lysine: 2-oxoglutarate 6-aminotransferase. The half reactions between an amino donor and the enzyme-bound pyridoxal 5'-phosphate, and also between an amino acceptor and the bound pyridoxamine 5'-phosphate followed first order reaction kinetics. The extrapolated first order rate constants and dissociation constants of the substrates were determined for the half reactions: lysine, 0.87 min-1 and 5.5 mM; glutamate, 1.1 min-1 and 10.5 mM; alanine, 0.66 min-1 and 6.6 mM; 6-aminohexanoate, 0.43 min-1 and 13.3 mM; and 2-oxoglutarate, 0.33 min-1 and 2.5 mM. As compared with the values reported for the overall reactions [Soda, K., Misono, H., & Yamamoto, T. (1968) Biochemistry 7, 4102-4109], the reactivity of the inherent substrates was lower by over 4 orders in the half reaction than that in the overall reaction, and the reactivity of alanine with the bound pyridoxal 5'-phosphate was reduced to 10% of that in the overall reaction. The substrate specificity in the half reaction was much lower than that in the overall reaction, which was re-examined in a reaction system containing the same concentration of the enzyme as that for the half reactions. Lysine 6-aminotransferase catalyzes the transfer of only the terminal amino group of lysine to 2-oxoglutarate in the overall reaction. However, in the half reaction, the 2-amino group as well as the terminal one was transferred to the bound pyridoxal 5'-phosphate. The ratio of reactivity of the 2-amino group to that of the 6-amino group was considerably influenced by the pH of the reaction mixture.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed1991

[Study of antibodies to motor end-plate in ocular myasthenia gravis].

This study was undertaken to investigate whether serum obtained from ocular MG with undetectable antibodies contains antibodies which bind to normal motor end-plates immunohistochemically. Nineteen patients with ocular MG were studied. Anti-AChR antibodies in serum were assayed by an immunoprecipitation method using human junctional AChR as the antigen. Anti-AChR antibodies in serum which bind to the junctional AChR at the motor end-plates were detected immunohistochemically by incubating the muscle with each serum. Bound IgG was detected by peroxidase labeled protein A (P-PA). IgG deposit at the own limb muscle motor end-plates (biceps brachii) was also detected by P-PA. Anti-AChR antibodies in serum were positive in 9 out of 19 patients and IgG antibodies bound to the junctional AChR were demonstrated in 16 of 19 patients. IgG bound to own end-plates was observed in 13 of 14 patients studied. In 2 patients IgG was detected at the own end-plates, but not at the not-self end-plates. These findings indicate that detection of IgG at the limb muscle end-plates serves for the diagnosis of ocular MG with undetectable antibodies in serum and anti-AChR antibodies in some patients may react exclusively with the autologous AChR.

Adolescent↗