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Biomedical subjects

H Kihara

Publications and source records attributed to H Kihara.

At least 91 records · Page 5Linked to original sources
PubMed1991

Changes in T-cell subpopulations induced by autonomic neurotransmitters and hormone.

In our previous studies, we found that changes in T-cell subpopulations were induced by restraint stress. To determine how this influence on the immune system was mediated pharmacologically, we studied the effects of autonomic agonists and antagonists and hydrocortisone on T-cell subpopulations in C3/H mice. These agents induced changes in the subpopulations of T-cells and modulated the receptors on T-cells. These drugs, however, did not have the same effect as restraint stress. This suggests that the effect of restraint stress on the immune system is mediated by other mechanisms. We found autonomic agents and hydrocortisone to affect differently T-cells in various organs. In general, acetylcholine and hydrocortisone affected T-cells in the thymus and adrenaline affected those in the spleen. By the double staining method, the maturity of these T-cells was found to be affected by these drugs. Remarkable changes were as follows. Thy 1, 2-positive T-cells were decreased in the blood and increased in the spleen while Lyt 2-positive T-cells were increased in the spleen by adrenaline. Thy 1, 2-positive T-cells were decreased in the thymus and increased in the blood while L3T4-positive T-cells and Lyt 2-positive T-cells in the blood were increased by acetylcholine. L3T4-positive T-cells were decreased in the thymus by atropine. Finally, Lyt 2-positive T-cells in the thymus were decreased and L3T4-positive T-cells in the blood were increased by hydrocortisone.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1991

[Psychosomatic study of inhalation therapy in patients with bronchial asthma. I. Evaluation by questionnaire].

We investigated the use of metered-dose beta agonist inhalers (MDIs) by means of 17-item questionnaires from the standpoint of psychosomatic medicine in 56 subjects with bronchial asthma. The results can be summarized as follows: 1) Many asthmatics with neurotic characters used MDIs frequently; Thirteen percent of them suffered adverse effects. The number of times the inhalers were used increased in proportion to the severity and the duration of illness. Fifteen percent of the subjects used MDIs frequently because of anxiety. 2) Fifty percent of the subjects, most of them had neurotic or alexithymic characters, used MDIs without suffering from dyspnea or wheezes; the subjects who used MDIs because of anxiety increased in proportion to the duration of illness. 3) Seventy eight percent of the subjects were anxious about asthmatic attack when they did not carry any MDI; sixty two percent of the subjects, most of them had neurotic or alexithymic characters, actually experienced asthmatic attack. 4) Seventy three percent of the subjects used MDIs secretly; sixty percent of the subjects did not like to inhale in the presence of others. 5) There were some subjects who acted incorrectly on or after asthmatic attack when MDIs were not effective.

Adolescent↗
PubMed1991

[Psychosomatic study of inhalation therapy in patients with bronchial asthma. II. Relationship between subjective self assessment of dyspnea and peak expiratory flow rates].

The degree of dyspnea when using metered-dose inhalers (MDIs), and the relationship between subjective self assessments and objective peak expiratory flow rates were examined by means of visual analogue scales and mini wright peak flow meters in 16 subjects with asthma. Three subjects who were neurotic in character were found to have a poor perception of the degree of airway obstruction after inhalation compared with objective changes in their condition. Two subjects, one neurotic and one alexithymic, assessed the degree of dyspnea to be worse after inhalation, when objectively there were few changes. However, one neurotic subject perceived an improvement in his condition when, in fact, there was little change. Furthermore, some severe cases used MDIs in the rogressive state of airway obstruction. In conclusion, we must pay attention to patients' characters when determining treatment in order to prevent overuse of MDIs or delays in treatments including the use of MDIs.

Adult↗
PubMed1990

Structural kinetics of the allosteric transition of aspartate transcarbamylase produced by physiological substrates.

We have studied the kinetics of the quaternary structure change associated with the allosteric transition of aspartate transcarbamylase (ATCase) (E. coli), inducing this change by exposure to the natural substrates (carbamyl phosphate and L-aspartate). The presence of 30% ethylene glycol slowed the quaternary structure change sufficiently for it to be followed by stopped-flow X-ray scattering at -5 degrees C. After adding substrates to the enzyme, the change occurred, with a half-life of a few seconds, yielding a mixture of the two standard quaternary structures (or, conceivably, a state intermediate between them). This mixture persisted until the enzyme reduced the substrate concentration below a threshold value.

Allosteric Regulation↗
PubMed1990

Binding of Cu(II), Tb(III) and Fe(III) to chicken ovotransferrin. A kinetic study.

The kinetics of binding of Cu(II), Tb(III) and Fe(III) to ovotransferrin have been investigated using the stopped-flow technique. Rate constants for the second-order reaction, k+, were determined by monitoring the absorbance change upon formation of the metal-transferrin complex in time range of milliseconds to seconds. The N and C sites appeared to bind a particular metal ion with the same rate; thus, average formation rate constants k+ (average) were 2.4 x 10(4) M-1 s-1 and 8.3 x 10(4) M-1 s-1 for Cu(II) and Tb(III) respectively. Site preference (N site for Cu(II) and C site for Tb(III] is then mainly due to the difference in dissociation rate constant for the metals. Fe(III) binding from Fe-nitrilotriacetate complex to apo-ovotransferrin was found to be more rapid, giving an average formation rate constant k+ (average) of 5 x 10(5) M-1 s-1, which was followed by a slow increase in absorbance at 465 nm. This slow process has an apparent rate constant in the range 3 s-1 to 0.5 s-1, depending upon the degree of Fe(III) saturation. The variation in the rate of the second phase is thought to reflect the difference in the rate of a conformational change for monoferric and diferric ovotransferrins. Monoferric ovotransferrin changes its conformation more rapidly (3.4 s-1) than diferric ovotransferrin (0.52 s-1). A further absorbance decrease was observed over a period of several minutes; this could be assigned to release of NTA from the complex, as suggested by Honda et al. (1980).

Animals↗
PubMed1990

Prevention of immunosuppression in stressed mice by neurotropin(NSP).

It is well known that the immune function can be compromised by stress. To investigate immune function in mice stressed by experimental restraint or unavoidable and opioid dependent stress, we evaluated the changes in total body weight and in organ weights (liver, spleen and thymus) of these animals, as well as the phagocytic activity of macrophages, the cytotoxicity of T cells and inhibitory effects on tumor growth and changes in T cell subset populations. At the same time we evaluated the effects of Neurotropin (NSP), a substance extracted from the inflamed skin of rabbits inoculated with the vaccinia virus and which appears to possess neuroimmunomodulating activity. The experimentally stressed group exhibited a reduction of phagocytic activity of macrophages, cytotoxicity of T cells and inhibitory effects on tumor growth. In addition there were changes in the population of T cell subsets. In those animals pretreated with NSP, the immunosuppression induced by stress was ameliorated. As compared with several agents which influence phagocytosis, neurotropin exhibited effects similar to that of agents that blocked the adrenaline receptor and an opioid antagonist rather than tranquilizer (diazepam) and a cholinergic receptor blocker. The pharmacologic effects of neurotropin support a relationship between the actions of the central nervous system and the immune system.

Animals↗
PubMed1990

Purification and amino acid sequence of basic protein I, a lysine-49-phospholipase A2 with low activity, from the venom of Trimeresurus flavoviridis (Habu snake).

A basic protein (pI 10.2), named basic protein I, was purified to homogeneity from the venom of Trimeresurus flavoviridis (Habu snake) after four chromatographic steps. The amino acid sequence of this protein was determined by sequencing the S-pyridylethylated derivative of the protein and its peptides produced by chemical (cyanogen bromide and formic acid) and enzymatic (chymotrypsin, Achromobacter protease I, and Staphylococcus aureus V8 protease) cleavages. The protein consisted of 122 amino acid residues and was similar in sequence to phospholipases A2 from the venoms of crotalid and viperid snakes. A most striking feature of this protein is that aspartic acid at the 49th position common in phospholipases A2 is replaced by lysine. When the protein acted on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphorylcholine, oleic acid was preferentially released, indicating that the protein has phospholipase A2 activity. Its molar activity toward 1,2-dilauroyl-sn-glycero-3-phosphorylcholine, however, was 1.5% that of T. flavoviridis phospholipase A2 isolated previously. The fact that both affinity to Ca2+ and reactivity to p-bromophenacyl bromide of basic protein I are approximately one order of magnitude lower than those of T. flavoviridis phospholipase A2 might explain the low activity of basic protein I.

Amino Acid Sequence↗
PubMed1990

Dissociation of Limulus polyphemus (horseshoe crab) hemocyanin. I. Solution X-ray scattering study in equilibrium.

A solution X-ray scattering study has been performed on Limulus polyphemus (horseshoe crab) hemocyanin and its dissociated fragments at various pH values in the presence and absence of Ca2+. The scattering patterns of native hemocyanin (48-mer), the half molecule (24-mer), quarter molecule (12-mer) and monomer fraction were measured. The radii of gyration for the four molecular species were calculated from the Guinier plots to be 110.7, 91.3, 77.3, and 36.5 A, respectively. Models which yield good fits to the experimental data are presented. The models were constructed using eight, four and two spheres with a radius of 58 A, assuming the sphere to be the submultiple composed of six subunits. The radii of gyration were calculated on the basis of the model and the values found to be 106, 94 and 73 A, respectively, in good agreement with the experimental results.

Journal Article↗
PubMed1990

Preliminary crystallographic study of phospholipase A2 from the venom of Trimeresurus flavoviridis (habu snake).

Crystallization and a preliminary crystallographic study of Trimeresurus flavoviridis (habu snake) phospholipase A2 (PLA2) were carried out. Although crystals were obtained from various solutions, crystals suitable for X-ray analysis could be obtained from polyethylene glycol solutions only when a repeated seeding technique was applied starting from twinned crystals. The crystal is monoclinic with space group P21, with a = 44.1, b = 55.7, c = 48.8 A, and beta = 92.4 degrees. An asymmetric unit contains a dimer consisting of two identical subunits made of 122 amino acids. The crystal reflects X-rays beyond 2.5 A. A Pt derivative gave a good isomorphous crystal.

Animals↗
PubMed1990

Purification and amino acid sequence of basic protein II, a lysine-49-phospholipase A2 with low activity, from Trimeresurus flavoviridis venom.

A basic protein (pI 10.3), named basic protein II, was purified to homogeneity from the venom of Trimeresurus flavoviridis (Habu snake) after four chromatographic steps. The amino acid sequence of this protein was determined by sequencing the S-pyridylethylated derivative and its peptides produced by chemical (cyanogen bromide) and enzymatic (chymotrypsin, clostripain, and Staphylococcus aureus V8 protease) cleavages. The protein consisted of 122 amino acid residues and was found to be identical in sequence to basic protein I from the same source except that Asp-58 of basic protein I is replaced by asparagine. Like basic protein I, the structural feature of basic protein II is that Tyr-28 and Asp-49 common in phospholipases A2 from snake venoms and mammalian pancreas are replaced by asparagine and lysine, respectively. Thus, basic protein II belongs to the category of lysine-49-phospholipase A2. The action of basic protein II on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphorylcholine released only oleic acid, indicating that it has phospholipase A2 activity. Its molar activity toward 1,2-dilauroyl-sn-glycero-3-phosphorylcholine, however, was only 1.7% of that of T. flavoviridis phospholipase A2 isolated previously. Affinity for Ca2+ and reactivity toward p-bromophenacyl bromide of basic protein II were 8 and 5.3 times, respectively, smaller than those of phospholipase A2 from the same source, substantiating the low phospholipase A2 activity of basic protein II.

Amino Acid Sequence↗
PubMed1990

Cloning and sequence analysis of cDNA for Trimeresurus flavoviridis phospholipase A2, and consequent revision of the amino acid sequence.

A cDNA clone of Trimeresurus flavoviridis phospholipase A2 was isolated from the venom gland cDNA library using DNA amplified by polymerase chain reaction with oligonucleotide primers corresponding to the N- and C-terminal sequences of this enzyme. The amino acid sequence deduced from the cDNA nucleotide sequence determined by the dideoxy termination method was found to be inconsistent in the segment comprising the 69th to 81st positions from that reported previously [Tanaka, S. et al. (1986) J. Biochem. 99, 281-289]. Reinvestigation of the amino acid sequence of the peptide covering the sequence in question showed that the amino acid sequence predicted from the nucleotide sequence is correct. The sequence contains Asn-Asn-Gly (positions 69-71) and it was found that the Asn-Gly bond easily undergoes alpha-beta transpeptidation when digested with Achromobacter protease I at pH 9.0 but not seriously at pH 6.8. It is likely that the transpeptidation reaction caused a failure in the previous sequence determination. The cDNA clone obtained was 597 base pairs long and contained an open reading frame of 414 base pairs coding for 138 amino acid residues. A typical signal peptide sequence (16 amino acid residues long), located at the N-terminal moiety of the deduced sequence, was immediately followed by a polypeptide which corresponds to the mature enzyme. Northern blot analysis showed a single transcript only in the poly(A)+ RNA fraction of the venom gland but not in those of many other organs tested.

Amino Acid Sequence↗
PubMed1990

Purification and characterization of a coagulant enzyme, okinaxobin I, from the venom of Trimeresurus okinavensis (Himehabu snake) which releases fibrinopeptide B.

A coagulant enzyme, named okinaxobin I, has been purified to homogeneity from the venom of Trimeresurus okinavensis (Himehabu) by chromatographies on Sephadex G-100 and CM-Toyopearl 650M columns. The enzyme was a monomer with a molecular weight of 37,000 and its isoelectric point was 5.4. The enzyme acted on fibrinogen to form fibrin clots with a specific activity of 77 NIH units/mg. Fibrinopeptide B was released at a rate much faster than fibrinopeptide A. The enzyme exhibited 2 to 3 times higher activity toward tosyl-L-arginine methyl ester and benzoyl-L-arginine p-nitroanilide than bovine thrombin. The esterase activity was strongly inhibited by diisopropylfluorophosphate and phenylmethanesulfonyl fluoride, and to a lesser extent by tosyl-L-lysine chloromethyl ketone, indicating that the enzyme is a serine protease like thrombin. The N-terminal sequence was highly homologous to those of coagulant enzymes from T. flavoviridis and Bothrops atrox, moojeni venoms which preferentially release fibrinopeptide A. In order to remove most, if not all, of the bonded carbohydrates, the enzyme was treated with anhydrous hydrogen fluoride (HF), thereby reducing the molecular weight to 30,000. The protein contained approximately 260 amino acid residues when computation was based on this value. The HF-treated enzyme retained about 50% of the clotting and esterolytic (TAME) activities and preferentially released fibrinopeptide B from fibrinogen. The carbohydrate moiety is not crucial for enzyme activity but might be necessary for eliciting full activity.

Amino Acid Sequence↗
PubMed1990

Effective therapy with low dose of oral cyclosporine A and prednisolone for alopecia universalis.

Although alopecia universalis is an incurable disease, we have obtained favorable results using a low dose of 2.5 mg/kg of cyclosporine A and 5 mg/day of prednisolone without adverse effects. We report our clinical experience of the treatment of two cases of alopecia universalis. Immunological examinations showed marked changes in the ratio of T cell subsets in peripheral blood. There was an increase of OKT8 positive cells and NK cells, reduction of IL-2R positive cells. These immunological changes following recovery from alopecia suggest a correlation between immunological disorders and the pathogenesis of this disease (alopecia universalis).

Administration, Oral↗
PubMed1990

[Pulmonary infiltration with eosinophilia possibly induced by cefotiam in a case of steroid-dependent asthma].

A 37-year-old female with refractory asthma taking betamethasone orally (1 mg/d), showed a fever of 38.5 degrees C, productive cough and dyspnea. The chest X-ray demonstrated diffuse infiltration in the left lower lung field. The WBC count was 16,000/mm3 with 6% eosinophils. She was treated with intravenous drip infusion of antibiotics (Cefotiam 2 mg/d and Sisomicin 150 mg/d) for 2 weeks, and her symptoms and the chest X-ray findings improved. However, at the end of the therapy eosinophilia was noticed. Sixteen days after the completion of antibiotic therapy, she again experienced fever, cough and dyspnea. The chest X-ray again demonstrated diffuse infiltrations in the left lower lung field. The total IgE level, histamine and circulating immune complex titers were elevated. The WBC count was 14,700/mm3 with 34% eosinophils. Although a sputum culture yielded no organisms, many eosinophils were observed in the sputum. There were no clinical or laboratory findings compatible with allergic broncho-pulmonary aspergillosis. After the administration of oral prednisolone (40 mg/d), the patient showed rapid improvement with resolution of all symptoms and normalization of the IgE, histamine and circulating immune complex levels. The chest X-ray revealed marked regression of the pulmonary infiltrations. A microscopic examination of a transbronchial biopsy specimen demonstrated moderate eosinophilic infiltrations. It was compatible with the diagnosis of pulmonary infiltration with eosinophilia. Treatment was performed with prednisolone. The result of a lymphocyte stimulation test was positive for Cefotiam. An in vitro test was performed to evaluate the diagnosis of drug allergy in this case.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Hemerythrin from Lingula unguis consists of two different subunits, alpha and beta.

Hemerythrin, a non-heme Fe-protein, of Lingula unguis has an octamer structure. We demonstrated that the protein is composed of two distinct subunits (alpha and beta), in equal amounts by investigation of their composition and partial terminal sequence. The cross-linking reaction of the native protein with dithiobis-(succinimidyl propionate) provided evidence for the presence of a dimer composed of alpha and beta subunits.

Amino Acid Sequence↗
PubMed1989

A monoclonal antibody that triggers deacylation of an intermediate thrombin-antithrombin III complex.

Upon incubation of antithrombin III with thrombin in the presence of a monoclonal antibody recognizing an epitope exposed on the heavy chain part of thrombin-cleaved two-chain antithrombin III, antithrombin III was preferentially cleaved by the enzyme as a substrate, rather than covalently complexed with the enzyme to form an equimolar, stable acyl complex. Once the stable acyl complex was formed between the enzyme and antithrombin III, however, no further liberation of two-chain antithrombin III was observed. Kinetic studies showed that heparin does not affect this reaction, although generation of thrombin-cleaved two-chain antithrombin III is apparently accelerated in accordance with the rate constant for heparin-enhanced thrombin-antithrombin III complex formation. Here we propose the term "switching antibody" for an antibody that triggers deacylation of an intermediate enzyme-inhibitor complex by switching the enzyme-inhibitor reaction from the major pathway of stable acyl complex formation to an alternative pathway of cleavage of the inhibitor as a substrate.

Antibodies, Monoclonal↗