Biomedical subjects

M Irie

Publications and source records attributed to M Irie.

At least 91 records · Page 5Linked to original sources

PubMed1998

[Psychosocial evaluation on the correct recollection of periodic medical checkups of workers. 2. Long-term change in the recalled results of medical checkups].

A self-administered questionnaire study of 333 workers (male 253, female 80) in a manufacturing company was carried out one month after informing the workers of the results of their medical checkups in 1993. The questionnaire included several items such as recalled abnormal findings of health examination and ways of overcoming the abnormal findings, recalled results of their medical checkups in 1992, self-confidence in their recollection of the results, and the usefulness of medical checkups. The following were investigated: the relationship between actual as well as recalled results of medical checkups in 1992 and the recollection of them after one year, the effects of examinations after medical checkups in 1992 on their recollection of the checkup results after one year, the effects of actual as well as recalled 1992 checkup results on the recollection of the results one month after informing the workers of the results of their medical checkups in 1993, assurance of correct recollection of the results, the relationship between the usefulness of medical checkups, explanation of abnormal findings and the percentage of correct answers to the results of medical checkups in 1993 one month after informing the workers of their results. It was found that the percentage of correct answers to the results after one year was significantly lower than that after one month in 1992. The rate decreased with the increase in the number of abnormal items in medical checkups. Moreover, the rate also decreased when the results were abnormal. Further examinations in addition to the medical checkups influenced their recollection somewhat after one year. The results that the workers still remembered in 1992 had a stronger effect on their recalling the results one month after informing them in 1993 than the actual results in 1992. The workers' confidence in their recollection of the results was untrustworthy in the same way as their recollection of the results, and they were not able to maintain the recollection of the correct results, although many of the workers realized the usefulness of the medical checkups. Our results suggest that explanation of abnormal medical findings in 1993 was effective because the percentage of partial concordance between actual and recalled results was much higher in the workers who received the explanation than in the workers who did not receive it.

Adult↗

PubMed1998

[Effect of walking during all weekdays, holidays, and at work on mental and physical health in workers].

In order to clarify the effects of walking under various psychosocial and occupational conditions on psychophysiological health, we examined the relationship between the number of steps walked in several situations, such as on all weekdays, at work, and over the weekend, and the results of medical checkups, psychological tests, Breslow's 7 health practices, and other attitudes toward walking as well as health by using a pedometer in a certain manufacturing company. Most of the workers estimated their usual number of steps walked as being less than actual levels on both weekdays and holidays. Generally, the increased number of steps walked was significantly correlated with increased HDL-cholesterol levels, and decreased Triglyceride levels. Contrary to such physical effects, there were more variations with respect to the relationship between walking and psychological health. Moreover, the development of a walking habit at work resulted in some factors becoming worse, such as relaxation, trait anxiety, and serum AST levels when compared to those on all weekdays and over the weekend. In conclusion, it is necessary to consider several situations in which workers usually walk and we must also practice counseling and education for health promotion, to promote walking for health care in the workplace.

Adult↗

PubMed1998

Flexural properties and swelling after storage in water of polyacid-modified composite resin (compomer).

The flexural properties, flexural strength, flexural modulus and modulus of resilience, of four commercially available compomers, and one resin-modified glass ionomer cement and one microfilled resin comosite (as controls) immediately after light-activation and after 1 week of water storage were tested to assess the mechanical properties. The water swelling after storage in water was also tested to assess the characteristics in water of compomers. The flexural test showed compomers to be statistically stronger and more resilient than the resin-modified glass ionomer cement or the microfilled composite, when tested immediately after light-activation and after 1 week of water storage. Water swelling of compomers was statistically less than the resin-modified glass ionomer cement after 1 week of water storage.

Analysis of Variance↗

PubMed1997

Binding of neuroligins to PSD-95.

PSD-95 is a component of postsynaptic densities in central synapses. It contains three PDZ domains that localize N-methyl-D-aspartate receptor subunit 2 (NMDA2 receptor) and K+ channels to synapses. In mouse forebrain, PSD-95 bound to the cytoplasmic COOH-termini of neuroligins, which are neuronal cell adhesion molecules that interact with beta-neurexins and form intercellular junctions. Neuroligins bind to the third PDZ domain of PSD-95, whereas NMDA2 receptors and K+ channels interact with the first and second PDZ domains. Thus different PDZ domains of PSD-95 are specialized for distinct functions. PSD-95 may recruit ion channels and neurotransmitter receptors to intercellular junctions formed between neurons by neuroligins and beta-neurexins.

Amino Acid Sequence↗

PubMed1997

SAPAPs. A family of PSD-95/SAP90-associated proteins localized at postsynaptic density.

PSD-95/SAP90 is a member of membrane-associated guanylate kinases localized at postsynaptic density (PSD) in neuronal cells. Membrane-associated guanylate kinases are a family of signaling molecules expressed at various submembrane domains which have the PDZ (DHR) domains, the SH3 domain, and the guanylate kinase domain. PSD-95/SAP90 interacts with N-methyl-D-aspartate receptors 2A/B, Shaker-type potassium channels, and brain nitric oxide synthase through the PDZ (DHR) domains and clusters these molecules at synaptic junctions. However, neither the function of the SH3 domain or the guanylate kinase domain of PSD-95/SAP90, nor the protein interacting with these domains has been identified. We have isolated here a novel protein family consisting of at least four members which specifically interact with PSD-95/SAP90 and its related proteins through the guanylate kinase domain, and named these proteins SAPAPs (SAP90/PSD-95-Associated Proteins). SAPAPs are specifically expressed in neuronal cells and enriched in the PSD fraction. SAPAPs induce the enrichment of PSD-95/SAP90 to the plasma membrane in transfected cells. Thus, SAPAPs may have a potential activity to maintain the structure of PSD by concentrating its components to the membrane area.

Amino Acid Sequence↗

PubMed1997

Role of histidine 46 in the hydrolysis and the reverse transphosphorylation reaction of RNase Rh from Rhizopus niveus.

In order to study the reaction mechanism of RNase Rh from Rhizopus niveus, the rates of cleavage of four 2',3'-cyclic nucleotides by mutant enzymes of RNase Rh, H46F, H109F, E105Q, and K108L were measured. H46F is virtually inactive towards cyclic nucleotides, but H109F hydrolyzed these substrates at 0.7-4.5% of the rates of the native RNase Rh. The other mutants hydrolyzed 2',3'-cyclic nucleotides at 15-20% of the rates of the native enzyme. Relative enzymatic activities towards four cyclic nucleotides of H109F in the hydrolysis reaction (2nd step) were much higher than in the transphosphorylation reaction (the 1st step). In the presence of a 13-fold excess of uridine, H109F catalyzed the transphosphorylation reaction of 2',3'-cyclic AMP (A>p) to ApU. However, this reaction was not catalyzed by H46F mutant or native RNase Rh. These results showed that His46 is crucial to the hydrolysis reaction, and to the reversed reaction of the transphosphorylation reaction. We suggest that His46 in RNase Rh plays a major role in these reactions by acting as a base catalyst to activate water and the 5'-hydroxyl group of nucleosides, respectively.

Binding Sites↗

PubMed1997

Primary structure of base non-specific and acid ribonuclease from bullfrog (Rana catesbeiana).

A base non-specific acid ribonuclease (RNase RCL2) was purified from bullfrog liver [H. Yagi et al. Biol. Pharm. Bull., 18, 219-222 (1992)]. The sequence study and comparison of the amino acid sequence of the enzyme with homologous RNases from oyster, drosophila and chicken liver suggested that the RNase RCL2 consisted of two components, large protein fraction (182 amino acid residues) and peptide 2 (20 amino acid residues) or peptide 1 (18 amino acid residues), and that both components bind with disulfide bridge. The RNase preparation was probably formed from a single polypeptide protein by processing with some proteases. The amino acid sequence of RNase RCL2 showed that the RNase belongs to the RNase of RNase T2 family and its sequence most resembles chicken liver acid RNase. In RNase RCL2, the amino acid residues which consist of the active site and major base recognition site of RNase Rh, a typical RNase of RNase T2 family, are very well conserved except for Tyr57 (RNase Rh numbering), and part of the amino acid residues of the minor base recognition site (Phe101 and Pro92) are also conserved.

Amino Acid Sequence↗

PubMed1997

Syntheses and antifungal activity of dl-griseofulvin and its congeners. III.

Several congeners (1b-g), with novel substituents on the benzene ring of griseofulvin, were prepared by the application of a synthetic method developed by us. Antifungal activity of these congeners decreased in order of dl-griseofulvin (1a) = 1d > 1b, c >> 1e-f (inactive). The relationship between the antifungal activity and the position or kind of substituents on the benzene ring of griseofulvin is discussed.

Antifungal Agents↗

PubMed1997

[Structures and functions of ribonucleases].

1. In order to understand the differences in pH optima and reaction rates of RNase A towards low molecular weight substrates and polymer substrates, the subsite structure of bovine pancreatic RNase A was studied. The kinetic studies of various sizes of oligouridylic acids showed that the size of the subsite is three nucleotides long. The kinetic studies on the inhibition of pUp, X-ray crystallographies of RNase A-ApC and pTp complexes, 31P-NMR studies on the binding of RNase A-pAp, and pTp showed the presence of P0, P2 and B3 sites. The location of the P0 site was assigned to be Lys66 by X-ray crystallography of the RNase A-pTp complex. The location of the P2 and/or P3/B3 site was determined by studying the enzymatic activities of several S-peptide analogs in which N-Leu was substituted for Lys7 and/or Lys1 coupled with S-protein toward various chain lengths of oligouridylic acids. The experiment suggested that P2 is Lys7 and P3/B3 is Lys1. 2. Several new pyrimidine base specific RNases were isolated and their primary structures were determined. They were two non-secretory RNases, a bovine liver alkaline RNase, a bovine brain RNase, and a bullfrog liver RNase. The bovine brain RNase has extra 16 amino acids at the C-terminus with O-glycosylated Ser. The bullfrog liver RNase was an extremely heat-stable RNase so far known. 3. Two new RNases belonging to RNase T1 family were isolated and their primary structures were elucidated. They were RNases isolated from Aspergillus saitoi and a mushroom (hiratake). The former RNase has a similar structure to RNase T1, but it was a base non-specific and guanylic acid preferential enzyme. From the results of X-crystallographic studies of this RNase, we suggested that the mechanism of RNase T1 RNase is essentialy a general acid-base catalysis between His40 and Glu58. 4. We isolated several fungal, plant and animal base non-specific acid RNases with a molecular mass about 24 kDa or more, and elucidated their primary structures. These RNases contain two sequences containing common 7-8 amino acid residues in common which include most of the amino acid residues important for the catalysis. Therefore, we proposed to designate these RNases as RNase T2 family RNase. On the basis of chemical modifications, kinetic studies and protein engineering studies of RNase Rh from Rhizopus niveus and RNase M from A. saitoi, we assigned that the catalytic site of RNase Rh consists of His46, His104, His109, Glu105, and Lys108. In the mechanism we proposed for RNase Rh, His46 and His109 work as a general acid and base catalysts. His104 was a phosphate binding site, and Glu105 and Lys108 might work to polarize a P=O bond of the substrate or stabilize the pentacovalent intermediate. However, in the reverse reaction of the transfer reaction step and the hydrolysis step of RNase Rh, His109 and His46 work as an acid and base catalyst, respectively. The X-ray crystallographic studies of RNase Rh, an RNase Rh-2'-AMP or d(ApC)complex, and the protein engineering studies of several mutant enzymes assigned the components of the major base recognition site (B1 site) and the minor base recognition site (B2 sites) of RNase Rh. The enzymatic studies of several mutant enzymes indicated that (i) Asp51 is very crucial for adenine base recognition, and the replacement of Asp51 by other amino acid, such as Thr, Ser, Glu, Asn makes RNase Rh more guanylic acid preferential, (ii) the replacement of Trp49 by Phe, and Tyr57 by Trp make the enzyme more pyrimidine and purine bases preferential, respectively. These trials are the first example of marked artificial change in the base specificity of RNases.

Amino Acid Sequence↗

PubMed1997

Enzymatic properties of double mutant enzymes at Asp51 and Trp49 and Asp51 and Tyr57 of RNase Rh from Rhizopus niveus.

Mutation of Asp51 of a base-nonspecific RNase, RNase Rh, to Ser, Thr, or Gln makes the enzyme more preferential for the dinucleoside phosphate (XpY) having G and C at the 5'-side (X). On the other hand the mutation of one of the B1 site components, Tyr57 to Trp, and Trp49 to Phe makes the enzyme more preferential for purine bases and pyrimidine bases, respectively. In this study, to obtain more specific RNases and RNases with different base specificity, we prepared double-mutant enzymes that have Ser, Thr, and Asn at the 51st position and Trp at the 57th position or Phe at the 49th position, and their enzymatic specificities were studied with XpYs as substrates. The double-mutant enzymes D51SY57W and D51TY57W are more guanylic acid preferential than the mother single-mutant enzymes, D51S and D51T, respectively. They are extremely guanylic preferential RNases. D51NY57W is more a guanylic acid preferential enzyme than D51N, but cytidylic acid preference is of a similar order to that of D51N. The double mutant enzymes D51NW49F and D51TW49F showed an increased cytidylic acid preference as well as guanylic acid preference as compared to the mother single-mutant enzymes, D51T and D51N. The results of analysis of base specificity by the release of mononucleotides from RNA and the rates of hydrolysis of homopolynucleotides led to the same conclusion as in the case of the hydrolysis of XpY.

Dinucleoside Phosphates↗

PubMed1997

The base specificities of tomato ribonuclease (RNase LE) and its Asp44 mutant enzyme expressed from yeast cells.

RNase LE from cultured tomato cells is a member of the RNase T2 family. It is, however, distinguishable from RNase Rh from Rhizopus niveus, a typical RNase of the RNase T2 family, by its CD spectrum in the 200-250 nm region. In order to reinvestigate the base specificity of RNase LE and to study the role of Asn44 in RNase LE, which is considered to correspond to the base recognition site Asp51 of RNase Rh, RNase LE, and its Asp mutant at the 44th position were expressed from yeast cells with the same expression system as RNase Rh [K. Ohgi, et al., J. Biochem., 109, 776-785 (1991)]. RNase LE with four extra amino acid residues at the 2nd amino acid residue of mature RNase LE and its Asp44 mutant were secreted from yeast cells to give a yield of 10 mg/liter and 0.5 mg/liter culture broth, respectively. The expressed RNase LE (RNase RNAP LE) had the same characteristics as native RNase LE in the CD spectrum and specific activity. This is the first example of the expression of plant RNase from microbes and in sufficient amount to perform further enzymological research. The base specificity of RNase LE was guanylic acid preferential and that of N44D was changed to a more adenylic acid preference as compared to that of RNase LE. These experiments showed that Asn44 of RNase LE is crucial for base recognition as the case of Asp51 in RNASE Rh, and also suggested that the base recognition mechanism of RNase LE is very similar to that of RNase Rh.

Amino Acid Sequence↗

PubMed1997

[The relationship between workers' attitudes towards health, lifestyle and mental health].

In order to investigate the relationship between health practices, various psychosocial factors, and mental health, a survey was conducted by means of a self-rating questionnaire on 424 industrial workers. The questionnaire included items concerning Goldberg's 12 selected items from the Japanese version of the General Health Questionnaire, the Type A scale used in the Framingham study, Breslow's 7 health practices, and other original psychosocial, health practicing items. A total of 391 or 92.2% responded to the questionnaire. Among them, 354 (266 males and 88 females) complete responders to the GHQ were analysed for the present study. As a result, several factors such as decrease in age, perceived present illness, worsening of perceived health status, increase in anxiety concerning health, exacerbation of alcohol and smoking related behaviour, decrease in physical exercise, reduction of Breslow's 7 health practices, perceived stress and difficulty in dealing with stress, increase in stress content, negative and malfunctional coping strategies, and decrease in relaxation were, according to the GHQ scores, related to negative mental health. Furthermore, Type A scores were significantly correlated to GHQ scores, the number of stress factors, and Breslow's 7 health practices in males, but they were weak or had no correlation in females. It is considered that favorable health practices and attitudes towards health might help to maintain positive mental health, but further analysis is needed to determine their causal relationships because of the cross-sectional design of the present study.

Adaptation, Psychological↗

PubMed1997

[Psychosocial evaluation on the correct recollection of periodic medical checkups of workers. 1. The ratio of correctly recalled results of medical checkups].

To investigate the usefulness of a periodic medical checkup at the workplace from the standpoint of remembering the results, a survey was performed by a self-rating questionnaire on 424 industrial workers in a certain manufacturing company. The questionnaire included several items, such as their recalled abnormal medical findings and follow-up toward them, Breslow's 7 health practices, Goldberg's 12 selected items from the Japanese version of the General Health Questionnaire, and other original health related items. The study was conducted a month after the workers received their results. A total of 391 (290 males and 101 females) or 92.2% responded to the questionnaire. Several factors, such as age, gender, the type of occupation, and perceived health status were significantly correlated to the recalled results of medical checkups, but, only age and the way of observing the results were in accordance with the actual results. Only forty-nine percent of the responders correctly remembered their results. Age and perceived health status were significantly correlated to the exact recollection of the results. In particular, those who had poor perceived health status tended to have a wrong understanding of their medical results. Furthermore, there were those with the highest averaged GHQ scores who responded as having some abnormal findings even though no abnormalities were discovered in the medical checkups. On the other hand, there were those with the lowest averaged GHQ scores who answered that they had no abnormal findings even though some abnormalities were revealed in the medical checkups. The frequency of correct follow-up of the results was lower than the exact recalling of the results. In addition, those who made a mistake in the follow-up were inclined to have an optimistic view. Therefore, comprehensive health care for precise recalling of the results of medical checkups should be required to improve abnormal findings or maintain a good health status.

Adult↗

PubMed1997

Primary structure of porcine spleen ribonuclease: sequence homology.

The primary structure of porcine spleen RNase (RNase Psp1) was investigated as a mean of assessing the structure-function relationship of base non-specific ribonucleases of animal origin. N-terminal analysis of RNase Psp1 yielded three N-terminal sequences. These peptides were separated by gel-filtration on Superdex 75HR, after reduction and S-carboxymethylation of RNase Psp1. Determination of the amino-acid sequence of these peptides indicated that the RNase Psp1 preparation consisted of three peptides having 20 (RCM RNase Psp1 pep1), 15 (RCM RNase Psp1 pep2), and 164 (RCM RNase Psp1 pro) amino-acid residues, respectively. It possessed two unique segments containing most of the active site amino-acid residues of the RNases of the RNase T2 family. The alignment of these three peptides in RNase Psp1 was determined by comparison with the other enzymes in the RNase T2 family. The overall results showed that RCM RNase Psp1 pep1 and RCM RNase Psp1 pep2 are derived from the N-terminal and C-terminal regions of RNase Psp1, respectively, probably by processing by some protease. The molecular mass of the protein moiety of RNase Psp1 was 23235 Da.

Amino Acid Sequence↗

PubMed1997

Effect of resin-modified glass ionomer cements on secondary caries.

PURPOSE: To evaluate the in vitro secondary caries inhibitory effect of two resin-modified glass ionomer cements (R-GICs). MATERIALS AND METHODS: Class V cavities were prepared at the cementoenamel junction on facial and lingual surfaces of 32 extracted upper premolars. The facial cavities were restored with a conventional glass ionomer cement (GIC) (Fuji II), while the lingual cavities were restored with either one of the R-GICs (Fuji II LC, Photac Fil, Vitremer), or a resin composite (Z-100). The margins of the restorations were subjected to a 20-day in vitro cariogenic challenge and the degree of demineralization was analyzed by microradiography. The amounts of fluoride released into distilled water from disc specimens of the materials tested were also measured for immersion time up to 161 days. RESULTS: The R-GICs and GIC's released similar cumulative amounts of fluoride over 161 days. Photac-Fil showed significantly higher amounts of fluoride release over the same period. The depth of the outer lesion and the thickness of the acid-resistant layer showed no significant difference among the R-GICs and GIC's. Moreover, the residual fluoride and calcium in the dentin adjacent to the R-GICs and GIC's were correlated with the thickness of acid-resistant layers in the dentin adjacent to the R-GICs and GIC's by electron probe microanalysis. However, the inhibitory effect of the R-GICs was not directly related to the fluoride concentrations eluted from them.

Bicuspid↗

PubMed1996

The crystal structure of ribonuclease Rh from Rhizopus niveus at 2.0 A resolution.

The three-dimensional structure of ribonuclease Rh (RNase Rh), a new class of microbial ribonuclease from Rhizopus niveus, has been determined at 2.0 A resolution. The overall structure of RNase Rh is completely different from those of other previously studied RNases, such as RNase A from bovine pancreas and RNase T1 from Aspergillus oryzae. In the structure of RNase Rh, two histidine residues (His46 and His109) and one glutamic acid residue (Glu105), which were predicted to be critical to the activity from the chemical modification and mutagenesis experiments, are found to be located close together, constructing the active site. The indole ring of Trp49 plays an important role in preserving the active site structure by its stacking interactions with the imidazole ring of His 109, and by hydrogen bonding with the carboxyl group of Glu105. There exists a hydrophobic pocket around the active site, which contains the aromatic side-chain of Trp49 and Tyr57. The results of mutagenesis studies suggest that this pocket is the base binding site of the substrate.

Amino Acid Sequence↗

PubMed1996

Enzymatic properties of mutant enzymes at Trp49 and Tyr57 of RNase Rh from Rhizopus niveus.

In order to establish the role of Tyr57 and Trp49 in the enzymatic reaction of RNase Rh, several mutant enzymes at Tyr57 and Trp49 were prepared by protein engineering and their enzymatic properties were investigated. Among the four mutant enzymes at Trp49 (W49F, W49Y, W49A, and W49I), W49F showed 16% of the activity of the native enzyme, but the others (W49Y, W49A, and W49I) showed greatly decreased activity. The data showed that Trp49 is very important for the enzyme activity. Among 8 mutant enzymes at the 57th position, Y57F and Y57W showed similar enzymatic activity toward RNA to that of the wild-type enzyme, but the others (Y57G, Y57A, Y57V, Y57M, and Y57K) are more active toward RNA and less active toward XpGs. The reason for the apparent increase for RNA activity is discussed from the view point of substrate inhibition. It is noteworthy that W49F and Y57W became more pyrimidine base- and purine base-preferential, respectively.

Amino Acid Sequence↗

PubMed1996

Enzymatic properties of mutant forms of RNase Rh from Rhizopus niveus as to Asp51.

In order to determine the role of Asp51 of RNase Rh from Rhizopus niveus, enzymes with mutations at the 51st position, D51N, D51E, D51Q, D51S, D51T, D51A, and D51K, were prepared, and their enzymatic properties were investigated as to specific activity and base specificity. All the mutant enzymes showed relatively high activity toward poly I and poly C, and markedly reduced activity toward poly A and poly U. In particular, the enzymatic activities toward poly I of D51T and D51S were higher than that of RNase RNAP Rh. Among the mutant enzymes, D51N, D51S, and D51T showed more than ca. 30% of the activity of RNase Rh, when RNA, poly I and poly C were used as substrates, respectively. The substitution of Ala, Glu, or Lys at Asp51 is unfavorable for enzymatic activity. Among XpGs (X = A, G, U, or C), D51N, D51S, and D51T showed higher activity toward GpG then CpG. Therefore, Asp51 in RNase Rh plays a critical role in the adenylic acid preference of RNase T2 family enzymes. Our results obtained with a protein engineering technique provide basic insights into the control of the base specificity of RNase Rh.

Amino Acid Sequence↗