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Biomedical subjects

H Kihara

Publications and source records attributed to H Kihara.

At least 19 recordsLinked to original sources
PubMed1992

Unusually high conservation of untranslated sequences in cDNAs for Trimeresurus flavoviridis phospholipase A2 isozymes.

As a step toward understanding the structure and function of phospholipases A2 (PLA2s), we isolated and sequenced several cDNAs encoding Trimeresurus flavoviridis venom PLA2 isozymes including two [Lys49]PLA2s called basic proteins I and II, [Thr37]PLA2, and PLX'-PLA2. Comparison of the nucleotide sequences of these cDNAs with the previously isolated [Asp49]PLA2 cDNA revealed some interesting findings from the viewpoint of evolution. First, the homologies of the 5' and 3' untranslated regions (98% and 89%, respectively) were much higher than that of the protein-coding regions (67%). The predicted secondary structure showed the characteristic stem-loop structures for both the untranslated regions of the mRNAs, suggesting that these regions play some functional role(s) in translation or stability of mRNAs. Second, base substitutions appeared to have occurred at similar rates for the three positions of codons among these PLA2s. The results are discussed in terms of evolution of PLA2s. Northern blot analysis showed that these PLA2s are specific to venom gland.

Amino Acid Sequence↗
PubMed1992

Resonance Raman study on the active-site structure of a cooperative hemerythrin.

Resonance Raman spectra were observed for the oxy and azidomet forms of a cooperative hemerythrin (Hr) isolated from Lingula unguis and a noncooperative Hr from Siphonosoma cumanense. The O-O stretching frequency of the oxy derivative of the L. unguis Hr was lower in the high-affinity form generated at pH 7.6 than in the low-affinity form generated at pH 6.2, while that of the S. cumanense Hr did not change at those two pH values. The Fe-O-Fe symmetric stretching mode of L. unguis azidomet-Hr exhibited a frequency shift between pH 7.6 and 6.2, while that of S. cumanense was not shifted. However, the corresponding band of the oxy form did not show a pH-dependent frequency change. Therefore, it is noted that the azidomet form is not a suitable model for studying a mechanism of cooperativity, contrary to the structural similarity between the oxy and azidomet forms. The Fe-O2 as well as Fe-N3 stretching frequencies were found to have no relation with the oxygen affinity. Upon exchange of solvent from H2O to D2O, the O-O and Fe-O2 stretching modes of L. unguis Hr were shifted to higher and lower frequencies, respectively, and their magnitudes were the same for the high- and low-affinity forms. The same frequency shifts were observed for S. cumanense Hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Kinetics of the reconstitution of hemoglobin from semihemoglobins alpha and beta with heme.

Kinetics of the reconstitution of hemoglobin from semihemoglobins alpha and beta with hemin dicyanide have been investigated using three kinds of stopped-flow technique (Soret absorption, fluorescence quenching of tryptophan, and Soret CD). The semihemoglobins alpha and beta are occupied by heme in the alpha and beta chains, respectively, the other chain being heme-free. Based on the kinetic results, the following scheme for the reconstitution is proposed; First, hemin dicyanide enters the pocket-like site of the apo chains. Second, in semihemoglobin alpha, the CN-ligand in the fifth coordination position of iron is replaced by the imidazole ring of the proximal His immediately after the heme insertion. In contrast, semihemoglobin beta changes its conformation after the heme insertion, and this is followed by the ligand replacement. Finally, the partial structure changes induced by the ligand replacement propagate onto the whole molecule and the final conformation is attained. The results indicate that semihemoglobin alpha retains a more rigid and organized structure, and more closely approaches its final structure than does semihemoglobin beta.

Animals↗
PubMed1992

The alpha beta complexes of ATP synthase: the alpha 3 beta 3 oligomer and alpha 1 beta 1 protomer.

The basic structures of the catalytic portion (F1, alpha 3 beta 3 gamma delta epsilon) of ATP synthase are the alpha 3 beta 3 hexamer (oligomer with cooperativity) and alpha 1 beta 1 heterodimer (protomer). These were reconstituted from the alpha and beta subunits of thermophilic F1 (TF1), and the alpha 3 beta 3 hexamer was crystallized. On electrophoresis, both the dimer and hexamer showed bands with ATPase activity. Using the dimer and hexamer, we studied the nucleotide-dependent rapid molecular dynamics. The formation of the hexamer required neither nucleotide nor Mg. The hexamer was dissociated into the dimer in the presence of MgADP, while the dimer was associated into the hexamer in the presence of MgATP. The hexamer, like mitochondrial F1 and TF1, showed two kinds of ATPase activity: one was cooperative and was inhibited by only one BzADP per hexamer, and the other was inhibited by three BzADP per hexamer.

Nucleotides↗
PubMed1992

Analysis of borderline-resistant strains of methicillin-resistant Staphylococcus aureus using polymerase chain reaction.

Identification of methicillin-resistant Staphylococcus aureus by drug-susceptibility tests alone poses a serious problem, because a considerable number of clinical S. aureus isolates are borderline resistant to methicillin. To circumvent this problem, we have developed a quick and sensitive method of PCR amplification for the detection of mecA gene, which, coding for PBP2', is the specific genetic element of methicillin-resistant Staphylococcus aureus. This method made it possible to identify MRSA strains in a short time using as few as 30 cells as a starting material for template DNA. Using this method, we found that the strains of borderline methicillin-resistance could be accurately identified. We also found one S. aureus clinical strain, T3, which lacked mecA gene in spite of its resistance to methicillin.

Base Sequence↗
PubMed1992

Echocardiographic evaluation of pulmonary arterial hypertension in patients with progressive systemic sclerosis and related syndromes.

In order to evaluate the usefulness of echocardiography in detection and characterization of pulmonary arterial hypertension (PAH) in scleroderma patients, we performed M-mode, two-dimensional, and Doppler echocardiography in 71 patients with progressive systemic sclerosis (PSS) and related syndromes: mixed connective tissue disease (MCTD) and overlap syndromes. We estimated systolic pressure gradients across the tricuspid valve from the peak velocity of tricuspid regurgitation (TR) by color-flow guided continuous wave Doppler. TR velocities of analyzable quality for gradient estimation were obtained in 28 patients (39%), of whom 12 showed PAH (peak TR velocity > or = 2.5 m/sec). In comparison, analyzable TR was recorded in 19 (35%) of 55 patients with left-sided cardiac disease. None of the 12 with Doppler-estimated PAH showed left ventricular dilatation or decreased fractional shortening by M-mode and two-dimensional measurements. Nonsimultaneous cardiac catheterization confirmed PAH in 8 of 9 with Doppler-estimated PAH and in 3 of 12 without analyzable TR who had hemodynamic study. Doppler-estimated right ventricular systolic pressures (RVSP) correlated well with catheterization-measured pulmonary arterial systolic pressures (PASP) (< 0.01). Our results indicate that Doppler echocardiography is useful in detecting subclinical PAH and estimating PASP in patients with collagen vascular disease. The results of pulmonary function studies suggest that PAH in MCTD is mainly caused by pulmonary vasculopathy.

Adult↗
PubMed1992

Myotoxicity and physiological effects of three Trimeresurus flavoviridis phospholipases A2.

When basic proteins I and II from Trimeresurus flavoviridis (Habu snake) venom, which are Lys-49-phospholipase A2 (PLA2) with low activity, were injected intramuscularly into mice, myonecrosis was induced accompanied by a rapid increase of plasma creatine kinase level. This increase was about 2 times greater than that raised by highly active T. flavoviridis Asp-49-PLA2 which has been regarded as a myotoxic factor. Calcium-dependent depolarization of frog muscle fibers was observed with basic proteins I and II but not with Asp-49-PLA2. Indirect hemolysis of rat erythrocytes was induced by Asp-49-PLA2 but not by basic proteins I and II. Myotoxicity and depolarization effects appear to be not necessarily related to lipolytic activity of proteins although hemolytic effects is in parallel to lipolytic potency. Light microscopic observations of muscle preparations treated with three PLA2s showed similar histological changes, i.e., myolytic necrosis without hemorrhage and infiltration of polymorphonuclear cells. The structural and functional elements of PLA2s for eliciting myotoxicity are discussed.

Amino Acid Sequence↗
PubMed1992

[Two cases of vocal cord dysfunction and bronchial asthma indicated contrary course of bronchial responsiveness based on astography].

We encountered two cases of patients who showed vocal cord dysfunction and bronchial asthma. By using an ++astograph , we found that bronchial responsiveness of these ailments differed. In the case of vocal cord dysfunction, bronchial responsiveness to methacholine indicated a false high level by adduction of the vocal cord. Therefore other evaluations including pulmonary function and bronchoscopy were required to distinguish it from bronchial asthma. On the other hand, in the case of bronchial asthma, bronchial responsiveness to methacholine was mild, but life threatening asthmatic attack occurred after inhalation of methacholine. Psychological factors were not neglected in considering both of these cases. Therefore we must consider these results and psychological factors when evaluating bronchial responsiveness.

Adolescent↗
PubMed1992

[Anatomical study of the normal and degenerative articular surfaces on the first carpometacarpal joint].

Specimens of 138 first carpometacarpal joints (CMJ) from cadavers consisting of 59 females and 79 males and averaging 68.8 years of age were grossly evaluated and morphological measurements were performed. Macroscopic degeneration of cartilage surface was noted in the metacarpus of 97 hands and trapezium of 73 hands. 1) Morphological measurements of normal articular surfaces showed that metacarpal concave depth was shallower in the female than in the male and trapezial convex height was flatter in the female than in the male. 2) The degeneration of the articular surface was more often observed in the metacarpal joint than the trapezial joint, and the degree of degenerative changes on each articular surface was greater in the female than in the male. 3) In Grade I, the degeneration of the cartilage surface was observed both in the radial and ulnar facets of the trapezium and in the dorsal and palmar facets of the metacarpus. 4) As the degeneration progressed in both sexes, the trapezial concavity became deeper and its convexity became flatter than normal. On the other hand, the metacarpal concavity was flatter and its convexity was higher than normal. Moreover, these changes were more apparent in the female than in the male.

Adult↗
PubMed1992

[Graduated psychosomatic treatment and quality of life in asthmatics].

We investigated the quality of life (QOL) in 72 patients with bronchial asthma who are under our gradational psychosomatic treatment (GPT) by means of an 11-item questionnaire. The results were summarized as follows: 1) Ninety-two percent of the subjects showed a good understanding of mind-body relations and modified their stressful adaptive patterns. 2) Asthmatic symptoms improved in 86 percent of the subjects. Other symptoms also improved in 72 percent of the subjects. 3) In 81 percent of the subjects, their daily life improved. Furthermore 96 percent of the subjects obtained some advantages through GPT. 4) There were various improvements in psychological states, personal relations and life style in most of the subjects. 5) The attitudes of their families toward the patients improved in 46 percent of the subjects, however 71 percent of the families developed a better understanding of the cause of asthma from the psychosomatic point of view. 6) Most of the subjects with moderate or severe symptoms were considered to have reduced the grade of severity of their symptoms from the doctor's standpoint.

Adult↗
PubMed1992

[A case of vocal cord dysfunction diagnosed as bronchial asthma, that was improved by psychosomatic therapy].

A 19-year-old psychologically disturbed female was admitted to our hospital because of intractable dyspnea and wheezing for twenty two months. She had been diagnosed as having asthma and had received several medications including steroids before admission to our hospital. According to our clinical observations, she was considered not to have asthma because neither FEV1.0 nor PaO2 was decreased during the periods of wheezing and FEV1.0 was not changed by inhalation of bronchodilators, although she had a family history of allergy and false bronchial hyperreactivity by asthograph. On physical examination, diffuse wheezing was heard mainly over the larynx during inspiration at the times of dyspnea. There was flattening of the inspiratory flow-volume loop during wheezing. Bronchoscopy performed during an attack confirmed that wheezing was due to adduction of the vocal cords throughout the respiratory cycle. Therefore, this case was diagnosed as vocal cord dysfunction. Her symptom was considered to be a form of conversion reaction derived from her unhappy past history. Following psychosomatic therapy, all of her medications became unnecessary. She understood the mind-body relationship of her condition, and learned to achieve self-control.

Adult↗
PubMed1991

Influence of stress on the maturity of T-cells.

Stress is known to influence the immune function via an effect on the central nervous system. We previously presented data showing that stress alters the population of T-cell subsets in mice. The variations of T-cell subsets in the thymus, peripheral blood, and spleen in mice similarly stressed by immobilization or by unavoidable and opioid-dependent stress were measured by flow cytometry using the monoclonal antibodies anti-L3T4, anti-Lyt 1, anti-Lyt 2 and anti-Thy 1, 2. Immobilization stress was applied for three days and T-cell subsets were measured on the days 1, 2 and 3, as well as on day 7 after release from immobilization. Lyt 2-positive cells in the thymus were the most sensitive to stress, showing significant variations. The proportion of immature T-cells increased in the thymus, blood and spleen of the stressed mice. When diazepam or naloxone were administered 30 min before the initiation of stress, these variations tended to decrease. Thus, the ratio of T-cell subsets varied with the duration of immobilization stress. This appeared to be partly mediated by the opioid system and the central nervous system.

Animals↗
PubMed1991

Amino acid sequence of a phospholipase A2 from the venom of Trimeresurus gramineus (green habu snake).

Two phospholipases A2, named phospholipases A2-I and A2-II, were purified to homogeneity from the venom of Trimeresurus gramineus (green habu snake). The complete amino acid sequence of phospholipase A2-I was determined by sequencing the native protein and the peptides produced by enzymatic (Achromobacter protease I, clostripain, and chymotrypsin) and chemical (hydroxylamine) cleavages of the S-pyridylethylated derivative of the protein. The protein consisted of 122 amino acid residues and was similar in sequence to phospholipases A2 from the venoms of crotalid snakes which belong to the category of Group II. A most striking feature of this protein is that tyrosine at the 28th position which is common in phospholipases A2 and is assumed to be a part of the Ca2(+)-binding loop is replaced by phenylalanine. Such replacement is the first finding in Group II phospholipases A2. Secondary structure compositions of phospholipase A2-I are similar to those of Crotalus atrox phospholipase A2. No appreciable Ca2(+)-induced difference spectrum was observed, due probably to the absence of the effective chromophoric groups in the neighborhood of the Ca2+ binding site although Ca2+ is bound with affinity similar to that for T. flavoviridis phospholipase A2.

Amino Acid Sequence↗
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↗