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Biomedical subjects

Koichi Miyaki

Publications and source records attributed to Koichi Miyaki.

17 recordsLinked to original sources
PubMed2007

Analysis of news of the Japanese asbestos panic: a supposedly resolved issue that turned out to be a time bomb.

BACKGROUND: Asbestos-linked public health problems were widely reported in Japan, in 2005. The objective is to apply text mining with network analysis to characterize these problems. METHODS: Text mining with network analysis of newspaper headlines including the word 'asbestos' published in 1987 and 2005 was conducted. Outcome measures are occurrence of the words and simultaneous occurrence of two words in the newspaper headlines. RESULTS: In 36 headlines, which contained the word 'asbestos' in 1987, the word 'pollution' (40%) appeared most frequently, followed by 'removal' (31%) and 'campaign' (29%). For combinations of words, the following occurred most frequently: 'campaign and expulsion' (26%) followed by 'removal and campaign' (14%). Of 293 headlines in 2005, the following words appeared: 'hazard' (31%), 'person' (16%) and 'death' (13%). For combinations, the following appeared: 'person and death' (9%). Asbestos pollution and removal campaigns were reported in 1987, but the death of citizens was reported in 2005. CONCLUSIONS: Text mining with network analysis, which presents one of the methods for visualization of text data, suggests the following insight. Insufficient steps against asbestos had been taken for 20 years, which is compatible with the latency period. It has resulted in widespread exposure to asbestos and more severe asbestos-related public health problems among citizens. This methodology suggests that analyzing text data by this method can serve future surveillance and efficient use of epidemiological knowledge.

Asbestos↗
PubMed2006

Coronary artery disease and a functional polymorphism of hTERT.

Genetic variation, a -1327T/C polymorphism, of human telomerase reverse transcriptase (hTERT) is associated with leukocyte telomere length in healthy subjects, but clinical significances of this functional polymorphism are not clear. Recently, the relationship between the telomere system and coronary artery disease (CAD) was reported. We investigated the association between the -1327T/C polymorphism and (a) susceptibility to CAD and (b) telomere length in CAD patients. In a case-control study, 104 patients confirmed by coronary angiography and 115 age- and sex-matched controls were enrolled. There was a higher frequency of the -1327C/C genotype in CAD patients (51.9%) compared with controls (36.5%, p = 0.0218). Among the 104 CAD patients, leukocyte telomere length in the -1327C/C genotype (7.62+/-2.19 kb, mean+/-SD) was shorter than that in the -1327T/C and -1327T/T genotypes (8.74+/-2.92, p = 0.0287). These findings suggest that the -1327C/C genotype is a genetic risk factor for CAD and relates to shorter telomere length among CAD patients.

Case-Control Studies↗
PubMed2006

Identification of ADRA2A polymorphisms related to shear-mediated platelet function.

alpha2A adrenergic receptor (ADRA2A) on platelets interacts with epinephrine, which has a key role in regulating platelet functions. There is familial clustering of inter-individual variations in the epinephrine-induced platelet aggregation, the molecular basis of which, however, has not been fully understood. In this study, we screened the sequence variations in the transcriptional region of ADRA2A gene and analyzed the relationship between the two common polymorphisms and platelet function using epinephrine/collagen cartridge in the platelet function analyzer-100 system, in a healthy Japanese male population (n=211). Among the identified 16 sequence variations including five novel variations, 1780GG genotype was associated with longer closure time which represents low platelet function under high shear-stress conditions (p=0.0478). We also observed enhanced effect of the combination of 1780GG and 2372AA genotypes on longer closure time (p=0.0319). These findings suggest that 1780A/G and 2372A/G polymorphisms are associated with platelet function in interactions with collagen/epinephrine.

Asian People↗
PubMed2006

Periodontal disease and atherosclerosis from the viewpoint of the relationship between community periodontal index of treatment needs and brachial-ankle pulse wave velocity.

BACKGROUND: It has been suggested that periodontal disease may be an independent risk factor for the development of atherosclerosis. However, the relationship between periodontal disease and atherosclerosis has not been fully elucidated. This study aimed to assess the effects of periodontal disease on atherosclerosis. METHODS: The study design was a cross-sectional study. Subjects were 291 healthy male workers in Japan. We used the Community Periodontal Index of Treatment Needs (CPITN) score, average probing depth and gingival bleeding index (rate of bleeding gums) to assess the severity of periodontal disease. We also used the Brachial-Ankle Pulse Wave Velocity (baPWV) as the index for the development of atherosclerosis. RESULTS: The unadjusted odds ratio (OR) of atherosclerosis in relation to the CPITN score was 1.41 [95% CI: 1.16-1.73]. However, after adjustment for age, systolic blood pressure and smoking, the CPITN score had no relationship with atherosclerosis (adjusted OR: 0.91 [0.68-1.20]). CONCLUSION: Our results show no relationship between mild periodontal disease and atherosclerosis after appropriate adjustments.

Adult↗
PubMed2006

Telomere length of normal leukocytes is affected by a functional polymorphism of hTERT.

Transcriptional regulation of human telomerase reverse transcriptase (hTERT), a catalytic subunit of telomerase, is essential for telomerase activity associated with telomere length. In this study, we investigated the effects of a (-1327)T/C polymorphism within the hTERT promoter region on the hTERT promoter activity and leukocyte telomere length in normal individuals. The promoter activity in the (-1327)T-sequence was significantly higher than that in the (-1327)C-sequence (p = 0.0004). For leukocyte telomere length, the (-1327)T-allele carriers had significantly longer than the (-1327)T-allele non-carriers (p = 0.0007). Also, there was no age-related shortening in leukocyte telomere length in the (-1327)T/T (p = 0.6633) and (-1327)T/C subjects (p = 0.1691), whereas there was clear age-related telomere shortening in the (-1327)C/C subjects (p = 0.0117). These findings suggest that the functional (-1327)T/C polymorphism of hTERT is associated with leukocyte telomere length in normal individuals.

Base Sequence↗
PubMed2006

Gorog Thrombosis Test: analysis of factors influencing occlusive thrombus formation.

We used the Gorog Thrombosis Test to analyze the factors influencing the occlusion time, which represents platelet activation and subsequent occlusive thrombus formation, in 132 healthy Japanese volunteers (116 men, 16 women; mean age, 45.0 +/- 12.0 years). The Gorog Thrombosis Test was designed to evaluate platelet aggregation and thrombolytic activity under a high shear stress condition (175 dynes/cm) in a native blood sample in vitro. The mean +/- SD occlusion time was 154.8 +/- 64.7 s (men, 153.4 +/- 64.2 s and women, 165.4 +/- 56.5 s). The occlusion time was inversely correlated with von Willebrand factor ristocetin cofactor activity (VWF:Rco) (r = -0.242, P = 0.0055) and von Willebrand factor antigen (r = -0.230, P = 0.0080). The mean occlusion time in the group with VWF:Rco of at least 170% (137 s) was significantly shorter than that in the group with VWF:Rco less than 170% (156 s, P < 0.05). Platelet counts, other coagulation markers and smoking showed no significant correlations with occlusion time. Red blood cells (r = -0.177, P = 0.0365), hemoglobin (r = -0.191, P = 0.0245) and hematocrit (r = -0.182, P = 0.0329) also showed inverse correlations with the occlusion time. This report is the first to clearly demonstrate the role of von Willebrand factor in the formation of occlusive thrombi in the Gorog Thrombosis Test.

Adult↗
PubMed2006

Two new criteria of the metabolic syndrome: prevalence and the association with brachial-ankle pulse wave velocity in Japanese male workers.

In 1998 and 2001, The World Health Organization and the National Cholesterol Education Program Adult Treatment Panel III proposed working criteria for the metabolic syndrome (MS), but they are not perfect for use in diverse ethnicities. In 2005, the International Diabetes Federation (IDF) and eight societies in Japan respectively proposed new criteria. However, there has been no report regarding the application of these new criteria in Japanese workplaces. We conducted a cross-sectional study of 377 healthy Japanese men aged 20-64 yr who worked in a chemical factory in Kanagawa, Japan. Participants completed a self-reported questionnaire, underwent a physical examination including waist measurements and brachial-ankle pulse wave velocity (baPWV), and provided overnight fasting blood samples. The prevalence of MS in Japanese men was 17.0% and 13.5% according to the new IDF and Japanese criteria respectively. In both of the new criteria, baPWV was significantly higher in those with MS than those without MS (1,563 +/- 264.2 vs 1,362 +/- 204.6 cm/sec, p<0.001 in the new IDF criterion; 1,574 +/- 265.2 vs 1,368 +/- 209.1 cm/sec, p<0.001 in the Japanese criterion). In the analysis of the 5 or 6 subgroups stratified according to the number of MS components, baPWV increased significantly with increasing number of MS components (p for trend<0.01 in both criteria). The new IDF and Japanese criterion are both good for diagnosing MS among Japanese because a linear increase in baPWV occurred with increasing MS components after adjustment for potential confounding factors. Further studies are expected using these new criteria.

Adult↗
PubMed2005

Association between glaucoma and gene polymorphism of endothelin type A receptor.

PURPOSE: Endothelin 1 (ET-1), a potent vasoconstrictor, may affect regulation of intraocular pressure and ocular vessel tone. Thus, ET-1 and its receptors may contribute to development of glaucoma. We investigated whether gene polymorphisms of ET-1 (EDN1) and its receptors ETA (EDNRA) and ETB (EDNRB) were associated with glaucoma phenotypes and clinical features. METHODS: We studied 224 normal Japanese controls and 426 open angle glaucoma (OAG) patients including 176 with primary open angle glaucoma (POAG) and 250 with normal tension glaucoma (NTG). Nine single nucleotide polymorphisms were detected among the participants using the Invader assay; four for EDN1 (T-1370G, +138/ex1 del/ins, G8002A, K198N), four for EDNRA (G-231A, H323H, C+70G, C+1222T), and one for EDNRB (L277L). Genotype distributions were compared between normal controls and OAG. Age at diagnosis, untreated maximum intraocular pressure (IOP), and visual field defects at diagnosis were examined for association with polymorphisms. RESULTS: Of the 9 polymorphisms, genotype distributions showed no significant differences between OAG patients and controls adjusted by age. The GG genotype of EDNRA/C+70G was associated with worse visual field defects in NTG patients (p=0.014; Mann-Whitney U test, and p=0.027; logistic regression analysis). CONCLUSIONS: The polymorphism of EDNRA/C+70G may be related to NTG risk factors.

Aged↗
PubMed2005

Assessment of tailor-made prevention of atherosclerosis with folic acid supplementation: randomized, double-blind, placebo-controlled trials in each MTHFR C677T genotype.

This study aimed at assessing the effect of folic acid supplementation quantitatively in each MTHFR C677T genotype and considered the efficiency of tailor-made prevention of atherosclerosis. Study design was genotype-stratified, randomized, double-blind, placebo-controlled trials. The setting was a Japanese company in the chemical industry. Subjects were 203 healthy men after exclusion of those who took folic acid or drugs known to effect folic acid metabolism. Intervention was folic acid 1 mg/day p.o. for 3 months. The primary endpoint was plasma total homocysteine level (tHcy). In all three genotypes, there were significant tHcy decreases. The greatest decrease was in the TT homozygote [6.61 (3.47-9.76) micromol/l] compared with other genotypes [CC: 2.59 (1.81-3.36), CT: 2.64 (2.16-3.13)], and there was a significant trend between the mutated allele number and the decrease. The tHcy were significantly lowered in all the genotypes, but the amount of the decrease differed significantly in each genotype, which was observed at both 1 and 3 months. Using these time-series data, the largest benefit obtained by the TT homozygote was appraised as 2.4 times compared with the CC homozygote. Taking into account the high allele frequency of this SNP, this quantitative assessment should be useful when considering tailor-made prevention of atherosclerosis with folic acid.

Alleles↗
PubMed2005

Surgical site infection surveillance after open gastrectomy and risk factors for surgical site infection.

Surgical site infection (SSI) surveillance was examined in gastric cancer patients who had undergone an open gastrectomy between 1997 and 2003 at Keio University Hospital in Tokyo, Japan. National Nosocomial Infections Surveillance (NNIS) reports and several studies have discussed SSI risk factors, but only open gastrectomy was analyzed by regression analysis. The purpose of this study was to examine these issues by performing a regression analysis for the prediction of SSI. SSI was defined by the surgical patient component according to the NNIS system (1999) produced by the Centers for Disease Control and Prevention. Patients undergoing an open gastrectomy were followed up and monitored for SSIs. Risk factors for SSI, after all factors were considered, were studied using single and multivariate analysis. The study enrolled 984 patients who had undergoing an open gastrectomy. Using multivariate and logistic regression analysis, the duration of the operation was identified as a [corrected] risk factor for SSI at open gastrectomy. Although numerous potential risk factors in surgical patients were examined, the duration of the operation was the only significant risk factor for SSIs after open gastrectomy.

Aged↗
PubMed2005

Salt intake affects the relation between hypertension and the T-786C polymorphism in the endothelial nitric oxide synthase gene.

BACKGROUND: Recent genetic studies have shown an association between the T-786C polymorphism in the endothelial NO synthase gene and coronary artery diseases, but any possible association with hypertension has been controversial. Other studies indicate the effect of restricting salt intake differ depending on individual salt-sensitivity, and the mixture of different sensitivity in study subjects may obscure the results. The objective of this study was to investigate the gene-environment interaction between the salt intake and this polymorphism. METHODS: We genotyped 281 healthy men after excluding 37 men on hypertensive therapy (mean age 44.8 +/- 11.9 years) for the mutation, and evaluated their daily salt intake using a validated food frequency questionnaire. RESULTS: A quartile classification of salt intake revealed that the blood pressure of subjects with the mutation was significantly higher than that of subjects without the mutation, but only in the 4th quartile (the highest intake group). A multiple logistic regression analysis also showed that the presence of this mutation increased the risk of hypertension only in the 4th quartile (adjusted odds ratio = 6.38, P = .025). CONCLUSIONS: The presence of this mutation alone does not significantly increase the risk of hypertension. However, high salt intake interacts with the mutation and leads to a significant increase in the risk of hypertension. The T-786C mutation warrants being considered a candidate for further study with the aim of tailor-made hypertension prevention.

Adult↗
PubMed2005

Genetic polymorphisms in the angiotensin II receptor gene and their association with open-angle glaucoma in a Japanese population.

PURPOSE: The local renin-angiotensin system (RAS) is present in the ciliary body and plays a role in regulating aqueous humor dynamics and thus intraocular pressure (IOP). The purpose of this study was to determine whether gene polymorphisms in the RAS increase the risk of development of glaucoma in the Japanese. METHODS: A case-control study was performed in 698 Japanese subjects: 190 patients with primary open-angle glaucoma (POAG), 268 patients with normal-tension glaucoma (NTG), and 240 normal subjects. Ten polymorphisms in seven genes-AGT/Thr174Met and AGT/Met235Thr; REN/I8-83G-->A; ACE/insertion(I)-deletion(D); CMA/-1930A-->G; AGTR1/-731T-->G, AGTR1/-521C-->T, and AGTR1/1166A-->C; AGTR2/3123C-->A; and CYP11B2/-344T-->C were examined. The age, IOP, and visual field defects, all at diagnosis, were examined to determine whether they were associated with the polymorphisms. The effects of oral angiotensin II receptor blocker (ARB) on IOP were examined in association with the AGTR1 and AGTR2 polymorphisms in 20 normal subjects. RESULTS: Of the 10 polymorphisms, the AGTR2/3123C-->A polymorphisms had a significantly different distribution in female patients with NTG; the frequency of the CA+AA genotypes was significantly higher than in female control subjects (P = 0.0095 for CC versus CA+AA). Although no significant difference was seen in the clinical characteristics of female patients with NTG who carried the AGTR2/3123C-->A genotype, patients with CC in the AGTR2 gene had significantly worse visual field scores if they carried ACE/ID+DD (i.e., D carriers; P = 0.012). ARB significantly lowered IOP in normal subjects, but the male subjects with the AGTR2/3123A genotype had significantly less lowering of IOP than those with the C genotype (P = 0.014). CONCLUSIONS: Angiotensin II receptor gene polymorphisms may be associated with the risk of glaucoma in the Japanese population.

Administration, Oral↗
PubMed2005

Effects of sarin on the nervous system of subway workers seven years after the Tokyo subway sarin attack.

This study was designed to assess the after effects of sarin exposure on the nervous system in victims of the Tokyo Subway Sarin Attack, which occurred on 20 March, 1995. We performed a similar study 3 yr after the disaster. This time, we newly enrolled 36 staff of the Teito Rapid Transit Authority (Tokyo Eidan subway) to assess the 7 yr after effects on the nervous system, and merged previous data including unpublished data to enhance statistical power. New subjects consisted of 23 male exposed subjects and 13 referent subjects matched for age and working types. Neurobehavioral tests for psychomotor function and memory, stabilometry, and Benton visual retention test were performed. As reported previously, the exposed group performed significantly less well in the psychomotor function test (tapping) than the referent group (117.8 +/- 1.2 vs. 105.6 +/- 1.2 msec). Using merged data, this phenomenon was also observed in a dose-dependent manner and the exposed group performed significantly less well in the backward digit span test (4.47 +/- 1.17 vs. 5.11 +/- 1.65 digits). These results indicate that chronic decline of psychomotor function and memory function still exist 7 yr after the sarin exposure.

Adult↗
PubMed2005

Increased risk of obesity resulting from the interaction between high energy intake and the Trp64Arg polymorphism of the beta3-adrenergic receptor gene in healthy Japanese men.

BACKGROUND: Few studies have investigated the interaction between the Trp64Arg polymorphism of the beta3-adrenergic receptor gene (ADRB3) and environmental factors. This study aimed to investigate whether energy intake affects the relationship between this polymorphism and obesity. METHODS: Healthy Japanese men (n=295; age 46.1+/-11.5 years (mean +/-standard deviation); waist circumference 83.9+/-9.3 cm; body mass index (BMI) 23.3+/-3.3 kg/m2) recruited in a Japanese chemical industry firm were eligible for analysis. Daily energy intake, protein, fat, and carbohydrate (PFC) ratio and daily physical activity were assessed by self-reported questionnaires. Genotyping for the polymorphism was performed with written informed consent. RESULTS: When the subjects were classified into two groups according to presence of the polymorphism, the groups were not significantly different in waist circumference or BMI. Quartile classification of energy intake, however, demonstrated a significantly larger ratio of obese subjects to non-obese subjects in the group with the polymorphism in the highest 4th quartile alone. Multiple logistic regression analysis also revealed that the presence of the polymorphism increased the risk of obesity significantly in the 4th quartile alone (adjusted odds ratio=3.37, 95% confidence interval=1.12-10.2). CONCLUSION: Presence of the polymorphism alone does not significantly increase the risk of obesity. However, high energy intake interacts with the polymorphism and leads to a significant increase in risk of obesity. The Trp64Arg polymorphism of ADRB3 warrants consideration, along with other polymorphisms involved in the development of obesity, for tailor-made prevention of obesity.

Body Mass Index↗
PubMed2004

High throughput multiple combination extraction from large scale polymorphism data by exact tree method.

Single nucleotide polymorphisms (SNPs) are increasingly becoming important in clinical settings as useful genetic markers. For the evaluation of genetic risk factors of multifactorial diseases, it is not sufficient to focus on individual SNPs. It is preferable to evaluate combinations of multiple markers, because it allows us to examine the interactions between multiple factors. If all the combinations possible were evaluated round-robin, the number of calculations would rapidly explode as the number of markers analyzed increased. To overcome this limitation, we devised the exact tree method based on decision tree analysis and applied it to 14 SNP data from 68 Japanese stroke patients and 189 healthy controls. From the obtained tree models, we succeeded in extracting multiple statistically significant combinations that elevate the risk of stroke. From this result, we inferred that this method would work more efficiently in the whole genome study, which handles thousands of genetic markers. This exploratory data mining method will facilitate the extraction of combinations from large-scale genetic data and provide a good foothold for further verificatory research.

Adult↗
PubMed2002

Novel statistical classification model of type 2 diabetes mellitus patients for tailor-made prevention using data mining algorithm.

To estimate the usefulness of data mining algorithms for extracting risk predictors of diabetic vascular complications in proper order in the future, we tried applying the Classification and Regression Trees (CART) method to the prevalence data of 165 type 2 diabetic outpatients and already known risk factors. Among the 6 categorical and 15 continuous risk factors, age (cutoff: 65.4) was the best predictor for classifying patients into groups with and without macroangiopathy (p=0.000). Body weight (cutoff: 53.9) was the best predictor (p=0.006) in the older group (age >65.4), whereas systolic blood pressure (cutoff: 144.5) was the best predictor in the remaining group (p=0.002). Age (cutoff: 64.8) was also the best predictor for categorizing them into groups with and without microangiopathy (p=0.000). In the older group (age >64.8), BMI (cutoff: 21.5) was the best predictor (p=0.001), whereas morbidity term (cutoff: 15.5) was the best predictor in the other group (p=0.01 0). Because the orders and values of all risk factors and cutoff points mined were reasonable clinically, this method may have the potential to highlight predictors in order of importance to apply tailor-made prevention of diabetic vascular complications.

Algorithms↗