Biomedical subjects

S Masui

Publications and source records attributed to S Masui.

At least 19 recordsLinked to original sources

PubMed2004

Chemiluminescent visualization of superoxide generated by Candida albicans.

The high toxicity of reactive oxygen species (ROS) suggested a possible role in the pathogenicity of human pathogenic fungi. We previously reported a chemiluminescence method for measuring ROS generation in Candida albicans. In the present study, we attempted to visualize the ROS, superoxide anion radical (O2-), generated by paraquat (PQ)-stimulated C. albicans using methyl-Cypridina-luciferin analog (MCLA) as a chemiluminescence probe. Colonies of a wild-type C. albicans parent strain and its respiration-deficient mutant grown on agar plates were overlaid with a mixture of PQ and MCLA solutions. MCLA-dependent light emission from the colonies was recorded with a Hamamatsu ultralow-light-imaging apparatus with a CCD camera in a light-tight box. In the wild-type strain, marginal regions of growing colonies were strongly illuminated. The light emission from the colonies was extinguished by superoxide dismutase (SOD), proving that the light emission was strictly due to the superoxide anion. However, colonies of the respiration-deficient mutant poorly generated superoxide. Chemiluminecence measurements by a luminometer showed vigorous superoxide generation by the exponential phase cells of the parent strain but weak generation by the stationary phase cells. In the mutant, superoxide generation was weak compared with the parent strain. These results indicate that expansion of the colonies was due to the actively respiring cells located in the marginal regions. To our knowledge, the present report is the first chemiluminescent visualization of ROS including superoxide generated by C. albicans.

Candida albicans↗

PubMed2002

Cigarette nicotine yields and nicotine intake among Japanese male workers.

OBJECTIVES: To analyse brand nicotine yield including "ultra low" brands (that is, cigarettes yielding less-than-or-equal 0.1 mg of nicotine by Federal Trade Commission (FTC) methods) in relation to nicotine intake (urinary nicotine, cotinine and trans-3'-hydroxycotinine) among 246 Japanese male smokers. DESIGN: Cross sectional study. SETTING: Two companies in Osaka, Japan. SUBJECTS: 130 Japanese male workers selected randomly during their annual regular health check up and 116 Japanese male volunteers taking part in a smoking cessation programme. MAIN OUTCOME MEASUREMENTS: Subjects answered a questionnaire about smoking habits. Following the interview, each participant was asked to smoke his own cigarette and, after extinguishing it, to blow expired air into an apparatus for measuring carbon monoxide concentration. Urine was also collected for the assays of nicotine metabolites. RESULTS: We found wide variation in urinary nicotine metabolite concentrations at any given nicotine yield. Based on one way analysis of variance (ANOVA), the urinary nicotine metabolite concentrations of ultra low yield cigarette smokers were significantly lower compared to smokers of high (p = 0.002) and medium yield cigarettes (p = 0.017). On the other hand, the estimated nicotine intake per ultra low yield cigarette smoked (0.59 mg) was much higher than the 0.1 mg indicated by machine. CONCLUSIONS: In this study of Japanese male smokers, actual levels of nicotine intake bore little relation to advertised nicotine yield levels. Our study reinforces the need to warn consumers of inappropriate advertisements of nicotine yields, especially low yield brands.

Administration, Inhalation↗

PubMed2001

Bacteriophage WO and virus-like particles in Wolbachia, an endosymbiont of arthropods.

Wolbachia are intracellular symbionts mainly found in arthropods, causing various sexual alterations on their hosts by unknown mechanisms. Here we report the results that strongly suggest that Wolbachia have virus-like particles of phage WO, which was previously identified as a prophage-like element in the Wolbachia genome. Wolbachia (strain wTai) infection in an insect was detected with the antibody against Wsp, an outer surface protein of Wolbachia, by fluorescence microscopy and immunoelectron-microscopy for the first time. Virus-like particles in Wolbachia were observed by electron-microscopy. The 0.22-microm filtrate of insect ovary contained DAPI-positive particles, and PCR analysis demonstrated that a phage WO DNA passed through the filter while Wolbachia DNA were eliminated, suggesting that the DAPI-positive particles were phage WO.

Animals↗

PubMed2001

[The effect of smoking cessation counseling at health checkup].

Smoking cessation counseling is an important element of tobacco control in the workplace, but it is not easy to persuade workers to stop smoking. We performed a controlled intervention trial to evaluate the effectiveness of a new cessation program developed by Nakamura et al., which consisted of one brief individual counseling session and 4 follow-up telephone calls. Two hundred and twenty-eight smokers who visited our center for an annual health checkup were randomly divided into two group: 117 were assigned to the intervention group, and 111 were controls. Smoking status questionnaires were administered to assess the smoking habit of each subject and to evaluate their stages of change toward smoking cessation before the counseling session. Stage-matched cessation counseling was then provided to the intervention group by nurses who had completed training courses for this program. During the counseling session, carbon monoxide in expired air and nicotine metabolites in urine were measured to enhance self-perception of smoking. Only those clients who set a quit date during their counseling sessions received follow-up telephone calls. It was easy to implement this program (15 to 20 minutes long) during a health checkup. No significant differences were observed in the baseline characteristics of the two groups. The cross-sectional smoking cessation rates at 6 months and 1 year of follow-up were 6.2 times higher in the intervention group than in the control group. The continuous smoking cessation rate at 1 year of follow-up was 7.6 times higher in the intervention group than in the control group. In the intervention group, the lower level of nicotine metabolites in urine and higher smoking stage were related to cessation success, but other baseline characteristics were similar in those who quit smoking and those who did not. The effectiveness and easy applicability of this cessation program was proved in the present study. Further examinations in various settings are expected to clarify the effectiveness of this program.

Adult↗

PubMed2001

Natural killer activity and its changes among participants in a smoking cessation intervention program--a prospective pilot study of 6 months' duration.

We examined the effect of smoking cessation on natural killer (NK) activity of peripheral blood lymphocytes in terms of a prospective study of 27 Japanese subjects who participated in a smoking cessation intervention program. This program was delivered by means of group-counseling offering 7 sessions of about 2 hours over 6 months to help smokers to discontinue the habit. Thirteen subjects ceased smoking (quitters), while 14 continued to smoke (cigarette smokers). NK activity before the intervention was correlated positively with age (correlation coefficient=0.46, P<0.05). NK activity remained almost constant among quitters, comparing the activity before and after the intervention, while it decreased among cigarette smokers although it was not statistically significant. In the subgroup analysis, NK activity increased among those aged less than 65 years, or urine cotinine levels over 800 ng/ml before the intervention, especially among quitters, but there were no statistical significances. Multiple regression analysis showed changes in NK activity were correlated significantly only with age (standard regression coefficient=-0.44, P<0.05). These findings suggest that smoking cessation intervention programs might have been more effective for younger than elder subjects in consideration of NK activity.

Aged↗

PubMed2000

Distribution and evolution of bacteriophage WO in Wolbachia, the endosymbiont causing sexual alterations in arthropods.

Wolbachia are obligatory intracellular and maternally inherited bacteria, known to infect many species of arthropod. In this study, we discovered a bacteriophage-like genetic element in Wolbachia, which was tentatively named bacteriophage WO. The phylogenetic tree based on phage WO genes of several Wolbachia strains was not congruent with that based on chromosomal genes of the same strains, suggesting that phage WO was active and horizontally transmitted among various Wolbachia strains. All the strains of Wolbachia used in this study were infected with phage WO. Although the phage genome contained genes of diverse origins, the average G+C content and codon usage of these genes were quite similar to those of a chromosomal gene of Wolbachia. These results raised the possibility that phage WO has been associated with Wolbachia for a very long time, conferring some benefit to its hosts. The evolution and possible roles of phage WO in various reproductive alterations of insects caused by Wolbachia are discussed.

Amino Acid Sequence↗

PubMed2000

Genes for the type IV secretion system in an intracellular symbiont, Wolbachia, a causative agent of various sexual alterations in arthropods.

Wolbachia species are intracellular bacteria known to cause reproductive abnormalities in their hosts. In this study, we identified Wolbachia genes encoding homologs to the type IV secretion system by which many pathogenic bacteria secrete macromolecules. The genes identified encoded most of the essential components of the secretion system and were cotranscribed as an operon.

Animals↗

PubMed2000

Wolbachia infection and cytoplasmic incompatibility in the cricket Teleogryllus taiwanemma.

Wolbachia are cytoplasmically inherited bacteria found in many arthropods. They induce various reproductive alterations in their hosts, including cytoplasmic incompatibility, thelytokous parthenogenesis, feminization and male-killing. In this study, we examined Wolbachia infection and its effects on the host cricket Teleogryllus taiwanemma. In a phylogenetic study based on the wsp gene coding for a Wolbachia surface protein, the Wolbachia strain harboured by T. taiwanemma was clustered together with those harboured by Laodelphax striatellus, Tribolium confusum, Acraea encedon, Trichogramma deion and Adalia bipunctata. Crossing experiments using the Wolbachia-infected and uninfected strains of cricket showed that the infection is associated with the expression of unidirectional cytoplasmic incompatibility: the egg hatch rate in the incompatible cross between the infected males and uninfected females was 20.3 %. We also examined the distribution of Wolbachia within the host using polymerase chain reaction assays; they were detected in the antennae, heads, forewings, hindwings, testes, ovaries, Malpighian tubules, foot muscles and fat bodies. Quantitative polymerase chain reaction assays showed that the bacterial density was highest in the fat bodies, followed by the ovaries and testes. Wolbachia were not detected in the haemolymph or in mature spermatozoa. The spermatozoa of the infected male may be modified by the presence of Wolbachia during its development. To examine this possibility, we compared the profiles of sperm proteins between the infected and uninfected males using two-dimensional gel electrophoresis. However, no differences in the protein profiles were observed.

Animals↗

PubMed2000

A new thiazolidinedione, NC-2100, which is a weak PPAR-gamma activator, exhibits potent antidiabetic effects and induces uncoupling protein 1 in white adipose tissue of KKAy obese mice.

Thiazolidinediones (TZDs) reduce insulin resistance in type 2 diabetes by increasing peripheral uptake of glucose, and they bind to and activate the transcriptional factor peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Studies have suggested that TZD-induced activation of PPAR-gamma correlates with antidiabetic action, but the mechanism by which the activated PPAR-gamma is involved in reducing insulin resistance is not known. To examine whether activation of PPAR-gamma directly correlates with antidiabetic activities, we compared the effects of 4 TZDs (troglitazone, pioglitazone, BRL-49653, and a new derivative, NC-2100) on the activation of PPAR-gamma in a reporter assay, transcription of the target genes, adipogenesis, plasma glucose and triglyceride levels, and body weight using obese KKAy mice. There were 10- to 30-fold higher concentrations of NC-2100 required for maximal activation of PPAR-gamma in a reporter assay system, and only high concentrations of NC-2100 weakly induced transcription of the PPAR-gamma but not PPAR-alpha target genes in a whole mouse and adipogenesis of cultured 3T3L1 cells, which indicates that NC-2100 is a weak PPAR-gamma activator. However, low concentrations of NC-2100 efficiently lowered plasma glucose levels in KKAy obese mice. These results strongly suggest that TZD-induced activation of PPAR-gamma does not directly correlate with antidiabetic (glucose-lowering) action. Furthermore, NC-2100 caused the smallest body weight increase of the 4 TZDs, which may be partly explained by the finding that NC-2100 efficiently induces uncoupling protein (UCP)-2 mRNA and significantly induces UCP1 mRNA in white adipose tissue (WAT). NC-2100 induced UCP1 efficiently in mesenteric WAT and less efficiently in subcutaneous WAT, although pioglitazone and troglitazone also slightly induced UCP1 only in mesenteric WAT. These characteristics of NC-2100 should be beneficial for humans with limited amounts of brown adipose tissue.

Adipose Tissue↗

PubMed2000

[The relationship between stages and biochemical markers of smoking. Workplace-based cross-sectional and longitudinal studies].

In order to clarify smokers' characteristics by "Stages of Change" based on Prochaska's transtheoretical model, we conducted cross-sectional and logitudinal studies with biochemical markers of smoking and smoking habits. In a workplace-based sample of 277 male smokers, we examined cross-sectionally the relationships between stages and biochemical markers of smoking which include expired carbon monoxide concentrations and urinary nicotine metabolite concentrations, and smoking habits which include the number of cigarettes smoked per day, yields of cigarettes, inhalation patterns, time to first morning cigarette, and quit attempts in the past. Additionally we examined longitudinally the relationship between stages and expired carbon monoxide concentrations, the number of cigarettes, and yields of cigarettes. In the cross-sectional study there were significant differences among stages on expired carbon monoxide concentrations (P = 0.006), urinary nicotine metabolite concentrations (P = 0.049), the number of cigarettes smoked per day (P = 0.001), and yields of cigarettes (P = 0.042) using analyses of variance. There were also significant differences among stages on time to first morning cigarette (P = 0.018) and quit attempts in the past (P < 0.001) using chi-square tests. In the longitudinal study for each level of elevation in stage during a one-year period, expired carbon monoxide concentrations decreased on an average of 2.3 ppm (P = 0.125) and the number of cigarettes smoked per day decreased on an average of 2.8 cigarettes per day (P = 0.07). However, the yields of cigarettes did not change during the one-year period.

Adult↗

PubMed2000

[Development and validation of a self-management skill scale].

OBJECTIVES: The aims of this study were: 1) to develop a scale for self-reported assessment of self-management skills (SMS), and to confirm its reliability and validity; 2) to verify its applicability to health services including health education by analyzing the relationship between the SMS score and behavioral changes among smoking cessation campaign participants. METHODS: A 20-item preliminary SMS scale was developed based on the previous findings of Rosenbaum's self-control schedule, social skills and life skills. A 10-item final SMS scale was developed by testing internal consistency and test-retest reliability among 55 subjects who were second to fourth-year college students (mean age: 20.9) in 1997. A questionnaire, including the SMS scale, self-efficacy for quitting smoking, and smoking cessation behavior was administered to 501 smokers (mean age: 46.3) who participated in the smoking cessation campaign that began in December 1997 and ended in June 1998. RESULTS: Among the participants of the smoking cessation campaign, the SMS scale showed a high level of internal consistency (Cronbach's alpha = 0.75) and positive correlations with age and self-efficacy for quitting smoking. The SMS scale also showed positive correlations with the outcome of the program, which means that those who had low SMS tended to drop out. CONCLUSION: The findings indicate that the SMS scale has acceptable levels of reliability and validity. They also suggest that it might be a useful instrument in health education and health services because the score correlates with people's health behavior.

Adult↗

PubMed1999

Optical resolution and absolute configuration of N-benzyloxycarbonyl-alpha-alkoxyglycines

Optical resolution of racemic N-benzyloxycarbonyl-protected alpha-alkoxyglycines, (+/-)-Cbz-Gly(OR)-OH (R = Et and Pr(i)), was achieved by means of fractional crystallization of diastereomeric salts with (+)-(1S,2S)-2-amino-1-phenyl-1,3-propanediol or diastereomeric esters of (+)- or (-)-menthol. The D- and L-configurations were assigned to the (+)- and (-)-Cbz-Gly(OR)-OH, respectively, based on L-enantioselective enzymatic hydrolysis of (+/-)-Cbz-Gly(OR)-OR' (R = Me, Et, and Pr(i); R' = CH(2)CF(3) and Me) using porcine pancreatic lipase and papain. Chiroptical properties and HPLC retention times of D- and L-Gly(OR)-residue (R = Me and Pr(i))-containing peptides were compared in relation to their configurational assignments. Copyright 1999 Wiley-Liss, Inc.

Journal Article↗

PubMed1999

The first detection of the insertion sequence ISW1 in the intracellular reproductive parasite Wolbachia.

Wolbachia are maternally inherited intracellular rickettsia-like bacteria known to infect a wide range of arthropods. They are associated with a number of different reproductive phenotypes in their hosts, such as cytoplasmic incompatibility, parthenogenesis, and feminization. We report on a novel insertion sequence (IS), ISW1, which was identified in the region downstream of groEL of a Wolbachia strain, wTai. The 573-bp-long ISW1 sequence is the first IS element observed in this organism, displays significant similarity to IS200, and lacks terminal inverted repeats. There were more than 20 copies of ISW1 on the chromosome of wTai. Sequence analysis of nine distinct ISW1 copies and their flanking regions showed that the copies were identical and suggested that ISW1 has no preference for its insertion sites. Possible roles of ISW1 in the adaptation of Wolbachia to intracellular environments and in various reproductive alterations caused by this bacterium are discussed.

Amino Acid Sequence↗

PubMed1999

[Development of a smoking cessation program during health checkups. Preliminary study to evaluate the usefulness of this program].

Development of a simple and effective smoking cessation program is needed to provide cessation counseling during health checkups. A new cessation program, which consists of brief individual counseling and 4 follow-up telephone calls, was developed based on the stage model for life-style change. This program was performed during health checkups in the town of Nose to evaluate its usefulness. Smoking status questionnaires were completed to assess the smoking habits of subjects and to evaluate their smoking stage before the counseling session. Then, stage-matched cessation counseling was provided using a self-help guide. During the counseling, carbon monoxide measurement of expired air and Health Risk Appraisal feedback were performed to enhance self-perception of smoking. Follow-up calls were provided for only those clients who set a quit date during the individual counseling. It was easy to implement this program, and it required between 15 and 20 minutes to conduct. The cessation rate was 19% at 8 months after the health checkups. This result was more effective than data for other programs reported previously. Therefore, this program was effective and could be used at health checkups. This trial had no control group, so further studies are needed to clarify the efficacy and effectiveness of this program. In addition, training courses for health professionals must be developed to disseminate this program into general use.

Adult↗

PubMed1998

A compact superconducting ring as a radiation source for X-ray crystallography.

A compact superconducting storage ring installed at Ritsumeikan University is operated at an electron-beam energy of 0.575 GeV and an initial beam current of 300 mA. The radius of the circular electron orbit is as small as 0.5 m, suggesting that the radiation emitted contains short-wavelength components. With an imaging plate as a detector, X-ray precession diffraction patterns were recorded for organic single crystals within a reasonable period of time using radiation of wavelength 0.155 nm (8 keV) to 0.248 nm (5 keV). The use of the radiation in the structural study of organic crystals containing 3d metal atoms using the phenomena of anomalous scattering is described. If appropriately planned, X-ray diffraction and/or scattering experiments can be made at the compact ring without recourse to a large-scale ring.

Journal Article↗

PubMed1998

XAFS spectra from reflectivity measurements.

The reflectivity of TiSi(2) films was measured as a function of photon energy E at the Ti K-edge region at a glancing angle theta close to the critical angle theta(C) of total reflection. TiSi(2) silicide films (about 30 nm thickness) were prepared by silicidation of Ti thin films deposited on Si(001) substrates. Since the Fresnel reflectivity R(theta,E) is a function of the dispersion delta(E) and of the absorption beta(E), the absorption beta(E) which carries the XAFS signal can be solved as beta(theta,delta,R) for observed reflectivity R and for estimated delta. The dispersion delta(E) is related to the absorption beta(E) by the Kramers-Kronig (K-K) relations since the refractive index is n(E) = 1 - delta(E) - ibeta(E). beta(E) was calculated from the observed reflectivity R(theta,E) using theoretical values for initial delta(E). Titanium K-edge XAFS for TiSi(2) was extracted from the reflectivity by 'ReflXAFS'.

Journal Article↗

PubMed1998

Design and performance of a multilayered mirror monochromator in the low-energy region of the VUV.

For the energy region from tens to hundreds of electron volts, the multilayered mirror (MLM) monochromator has never been realized due to the difficulty of reducing the background noise of the total reflection component, in spite of its usefulness in synchrotron radiation experiments. In this work, a double-crystal-type MLM monochromator equipped with a thin-film filter has been designed on the basis of trial fabrication of the mirror-driving system and of Mo/Si and Mo/C MLMs; its performance has been evaluated by calculating its output photon flux. It is shown that by using the MLMs at low incident angles, combined with an appropriate thin-film filter, it is possible to make a practical monochromator with high output photon flux and low background noise.

Journal Article↗

PubMed1998

Localization of rat FGF-5 protein in skin macrophage-like cells and FGF-5S protein in hair follicle: possible involvement of two Fgf-5 gene products in hair growth cycle regulation.

It has been reported that the gene for murine fibroblast growth factor-5 (Fgf-5) is expressed in the rat hair follicle and that this expression may be associated with catagen induction (Hebert et al, 1994). In this study, we analyzed the Fgf-5 gene product in skin because the gene generates two mRNA that translate into the FGF-5 protein and a short form of the FGF-5 protein (FGF-5S) as a result of an alternative splicing (Hattori et al, 1996; Ozawa et al, 1996). Indeed, we detected both types of FGF-5 mRNA in rat skin samples. Two monoclonal anti-FGF-5 antibodies, one (E723) being specific for FGF-5 long-form protein and the other (B2B6) being reactive with both FGF-5 and FGF-5S proteins, were used to locate these proteins by immunohistochemistry. Staining of the rat skin revealed that only the B2B6 antibody reacted with hair follicles and that both antibodies reacted with macrophage-like round cells, suggesting that the product of the Fgf-5 gene in the hair follicle is FGF-5S. The immunoreactivity of the FGF-5S protein increased during early anagen VI and decreased rapidly during catagen. The density of FGF-5-positive macrophage-like cells in the dermis increased during anagen and decreased during catagen and telogen, whereas the density of these cells in the panniculus adiposus did not change during anagen and increased during catagen and telogen. There was no apparent association between the density of FGF-5-positive macrophage-like cells and that of FGF-5-negative, dendritic macrophage-like cells. Thus, the results suggest the possible involvement of FGF-5S in the hair follicle in anagen VI and catagen development and that the density of FGF-5-positive macrophage-like cells may also be associated with the hair growth cycle.

Animals↗