Associations between weight change since 20 years of age and sleep-disordered breathing among male truck drivers

BACKGROUND

Limited evidence for association of weight gain with sleep-disordered breathing (SDB) has been produced for Asian populations whose body mass index (BMI) levels are lower than in western countries.

OBJECTIVE

The aim of this study was to examine weight change since 20 years of age and risk of SDB among Japanese.

DESIGN

Retrospective cohort study.

SUBJECTS

This study includes a large sample of 5320 male Japanese truck drivers aged 30-69 years.

MEASUREMENTS

The respiratory disturbance index (RDI) was selected as an indicator of SDB, and it was estimated with a one-night sleep test using an airflow monitor, and the Epworth Sleepiness Scale (ESS) was used to estimate excessive daytime sleepiness.

RESULTS

Respiratory disturbance and sleepiness were more prevalent among men with BMI of 25.0-29.9 and > or =30.0 kg/m(2) than among those with BMI of 18.5-24.9; multivariable odds ratios (ORs) were 1.8(1.5-2.0), P<0.001 and 4.4(3.5-5.5), P<0.001 for RDI > or =10, and 1.2(0.9-1.4), P=0.18 and 1.5(1.1-2.1), P=0.02 for ESS > or =11, respectively. Compared with men showing BMI changes within +/-1.0, the respective multivariable ORs for those with BMI changes of 3.0-4.9 and > or =5.0 were 1.4(1.2-1.6), P<0.001 and 2.4(2.0-2.9), P<0.001 for RDI > or =10, and 1.2(0.9-1.6), P=0.22 and 2.0(1.5-2.6), P<0.001 for ESS > or =11. The corresponding ORs for weight gain of > or =10.0 kg compared with weight change less than +/-5.0 kg were 2.0(1.7-2.4), P<0.001 for RDI > or =10 and 1.5(1.2-2.0), P=0.002 for ESS > or =11. Similar trends were observed for RDI > or =20.

CONCLUSION

Our results suggest that an increase in BMI of > or =5 kg/m(2) or weight gain of > or =10 kg is a risk factor for SDB and excessive daytime sleepiness among Japanese truck drivers.

Nocturnal intermittent hypoxia and the development of type 2 diabetes: the Circulatory Risk in Communities Study (CIRCS)

AIMS/HYPOTHESIS

Although the associations between obstructive sleep apnoea and type 2 diabetes mellitus have been reported in cross-sectional design studies, findings on the prospective association between the two conditions are limited. We examined prospectively the association between nocturnal intermittent hypoxia as a surrogate marker of obstructive sleep apnoea and risk of type 2 diabetes.

METHODS

A total of 4,398 community residents aged 40 to 69 years who had participated in sleep investigation studies between 2001 and 2005 were enrolled. Nocturnal intermittent hypoxia was assessed by pulse-oximetry and defined by the number of oxygen desaturation measurements < or =3% per h, with five to <15 per h corresponding to mild and 15 events or more per h corresponding to moderate-to-severe nocturnal intermittent hypoxia, respectively. The development of type 2 diabetes was defined by: (1) fasting serum glucose > or =7.00 mmol/l (126 mg/dl); (2) non-fasting serum glucose > or =11.1 mmol/l (200 mg/dl); and/or (3) initiation of glucose-lowering medication or insulin therapy. Multivariable model accounted for age, sex, BMI, smoking status, current alcohol intake, community, borderline type 2 diabetes, habitual snoring, excessive daytime sleepiness, sleep duration and (for women) menopausal status.

RESULTS

By the end of 2007, 92.2% of participants had been followed up (median follow-up duration [interquartile range] 3.0 [2.9-4.0] years) and 210 persons identified as having developed diabetes. The multivariable-adjusted hazard ratio (95% CI) for developing type 2 diabetes was 1.26 (0.91-1.76) among those with mild nocturnal intermittent hypoxia and 1.69 (1.04-2.76) among those with moderate-to-severe nocturnal intermittent hypoxia (p = 0.03 for trend).

CONCLUSIONS/INTERPRETATION

Nocturnal intermittent hypoxia was associated with increased risk of developing type 2 diabetes among middle-aged Japanese.

Cross-cultural comparison of the sleep-disordered breathing prevalence among Americans and Japanese

The aim of the present study was to compare the prevalence of sleep-disordered breathing among Hispanic and white Americans and Japanese. A 1-night sleep study using a single-channel airflow monitor was performed on 211 Hispanics and 246 Whites from the Minnesota field centre (St Paul, MN, USA) of the Multi-Ethnic Study of Atherosclerosis (MESA), and 978 Japanese from three community-based cohorts of the Circulatory Risk in Communities Study (CIRCS) in Japan. The respiratory disturbance index and sleep-disordered breathing, defined as a respiratory disturbance index of > or =15 events x h(-1), were estimated. The prevalence of sleep-disordered breathing was higher in males (34.2%) than females (14.7%), and among Hispanics (36.5%) and Whites (33.3%) than among Japanese (18.4%), corresponding to differences in body mass index. Within body mass index strata, the race difference in sleep-disordered breathing was attenuated. This was also true when body mass index was adjusted for instead of stratification. The strong association between body mass index and sleep-disordered breathing was similar in Japanese and Americans. The prevalence of sleep-disordered breathing was lower among Japanese than among Americans. However, the association of body mass index with sleep-disordered breathing was strong, and similar among the race/ethnic groups studied. The majority of the race/ethnic difference in sleep-disordered breathing prevalence was explained by a difference in body mass index distribution.

Low protein C and incidence of ischemic stroke and coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Protein C is an important plasma natural anticoagulant. Although protein C deficiency increases risk of venous thrombosis, it remains uncertain whether low protein C increases risk of atherothrombosis.

OBJECTIVE

To examine whether low protein C may be a risk factor for ischemic stroke or coronary events in a prospective population-based study.

PATIENTS/METHODS

The Atherosclerosis Risk in Communities Study assessed protein C antigen by ELISA at baseline in 1987-89 and followed participants (n = 13 879) for incident ischemic stroke or coronary events through 2005.

RESULTS

Over a median of 16.9 years of follow-up, 613 ischemic strokes and 1257 coronary heart disease events occurred. Protein C was inversely associated with incidence of ischemic stroke. Adjusted for multiple risk factors, the rate ratios (95% CIs) from highest to lowest quintiles were 1.0, 1.16 (0.90-1.50), 1.22 (0.94-1.58), 1.18 (0.90-1.55) and 1.52 (1.17-1.98). This inverse association was stronger for non-lacunar and cardioembolic stroke than for lacunar stroke. In contrast, there was a positive association between protein C and coronary heart disease in incompletely adjusted models, but no association after adjustment for plasma lipids.

CONCLUSIONS

In this cohort study, low protein C was a risk factor for incident ischemic stroke but not coronary heart disease. Levels of protein C associated with stroke risk were not restricted to the traditional 'deficient' range for protein C (< 0.5 percentile), suggesting that other etiologies for a lower protein C, or genetic variants associated with more subtle changes in protein C, are playing a role in disease pathogenesis.

Blood pressure and the risk of stroke, cardiovascular disease, and all-cause mortality among Japanese: the JPHC Study

BACKGROUND

Little is known about the influence of blood pressure (BP) on cardiovascular disease (CVD) outcomes among Asian populations.

METHODS

We examined population attributable fractions (PAFs) and hazard ratios (HRs) associated with BP in relation to stroke and coronary heart disease (CHD) incident and mortality within a cohort of 33,372 Japanese men and women aged 40-69 years, free of prior diagnosis of cancer and CVD. The BP was classified based on modified criteria of the 2003 European Society of Hypertension-European Society of Cardiology guidelines. A total of 943 stroke events, 182 CHD events, 262 stroke deaths, and 120 CHD deaths occurred between the baseline questionnaire (1990-1994) and the end of follow-up in 31 December 2003.

RESULTS

BP levels were linearly associated with incidence and mortality of CVD in men and women. According to the PAF estimation, the elimination of normal to severe hypertension would prevent 64% of stroke incidence in men and 50% in women; 67% of stroke mortality in men and 29% in women; and 38% of total CVD mortality in men and 36% in women. The PAF estimate for total stroke incidence was the highest for mild hypertension, and lower for moderate to severe hypertension in both sexes.

CONCLUSIONS

The contributions of normal BP, high normal BP, and mild hypertension to the occurrence of stroke events were greater than those made by moderate and severe hypertension, highlighting the importance of primary prevention and of treatment for low-to-moderate degrees of hypertension.

Modulation of gonadotrophin-releasing hormone pulse generator activity by the pheromone in small ruminants

In small ruminants, such as goats and sheep, a primer pheromone produced by males induces an out-of-seasonal ovulation in anoestrous females, a phenomenon known as the male effect. The male effect is unique in that an external chemical stimulus can immediately modulate the activity of the hypothalamic gonadotrophin-releasing hormone (GnRH) pulse generator. We have established a monitoring method of the GnRH pulse generator activity in Shiba goat. Using this method as a sensitive bioassay to assess the male effect pheromone activity, we have shown that the male effect pheromone is synthesised in an androgen-dependent manner in the sebaceous glands or their vicinity in specific body regions in goats. Although chemical identity of the pheromone is yet to be determined, analyses of male goat hair extracts by gas chromatography fractionation suggest that the male effect pheromone is a volatile substance with relatively small molecular weight. From morphological and molecular biological studies in goats, it is suggested that the pheromone molecule is detected by a member of the V1R family located on both the olfactory neurones and the vomeronasal sensory neurones, and the pheromone signal is conveyed to the medial nucleus of amygdala via the main olfactory and vomeronasal pathways and, subsequently, to the hypothalamic GnRH pulse generator to enhance its activity.

Body mass index and weight change since 20 years of age and risk of coronary heart disease among Japanese: the Japan Public Health Center-Based Study

BACKGROUND

Obesity and weight gain are associated with increased risk of coronary heart disease in Western countries. However, their impact is not well elucidated in Asia, where body mass index (BMI) levels are generally lower than in Western countries. We examined associations of BMI (kg/m(2)) and weight change with risk of coronary heart disease in Japanese people.

METHODS AND RESULTS

A total of 43 235 men and 47 444 women aged 40-69 years living in communities were followed up from 1990 to 2001 in the Japan Public Health Center-based (JPHC) prospective study . During 879 619 person-years of follow-up, we documented 399 cases of coronary heart disease (334 myocardial infarction and 65 sudden cardiac death) for men and 119 (95 myocardial infarction and 24 sudden cardiac death) for women. Compared with persons with BMI 23.0-24.9, men, but not women, with BMI >/=30.0 had higher risk of coronary heart disease and myocardial infarction; the multivariable relative risks for men were 1.8 (1.1-3.0) and 1.9 (1.1-3.2), respectively. When weight change was examined according to BMI at age 20 years, men with initial BMI <21.7 who gained more than 10 kg compared with men of no weight change had a twofold higher risk of coronary heart disease. Both men and women with initial BMI >/=21.7 showed no association between weight loss and the risk.

CONCLUSIONS

High BMI was associated with increased risk of coronary heart disease among men. Also, weight gain was associated with increased risk among lean men.

Parasitism, development and adult longevity of the egg parasitoid Telenomus nawai (Hymenoptera: Scelionidae) on the eggs of Spodoptera litura (Lepidoptera: Noctuidae)

When Telenomus nawai Ashmead or Trichogramma ostriniae Pang & Chen (Hymenoptera: Trichogrammatidae) was inoculated into intact egg masses of Spodoptera litura (Fabricius) that were covered with a scale-hair layer, T. nawai emerged from 76% of the eggs, while emergence of T. ostriniae was from only 3% of the eggs. When the hair layer was removed before inoculation, the rate by the latter increased to 21%. These observations confirmed that the hair layer effectively protects S. litura egg masses from attack by T. ostriniae, and that T. nawai parasitism is more effective. In order to assess the feasibility of T. nawai as a biological control agent for S. litura, parasitism rate, development time and adult longevity were examined in the laboratory. Emergence of T. nawai was observed in more than 95% of 0- and 1-day-old separated eggs of S. litura, but the rate decreased to 60% and 0% for 2- and 3-day-old eggs, respectively. The emergence rates of T. nawai were near 95% for temperatures in a range from 25 degrees C to 35 degrees C, but decreased to 80% at 20 degrees C. No parasitoids emerged at 15 degrees C. The developmental periods decreased as temperature increased from 20 degrees C to 35 degrees C. The developmental threshold occurred at 13.7 degrees C and 13.9 degrees C, and the effective accumulative temperatures from egg to adult emergence were 149.3 and 147.1 degree-days for females and males, respectively. Mean longevity of the adult females decreased with increasing temperature; 87.0 days at 15 degrees C and 9.5 days at 35 degrees C. The feasibility of the use of T. nawai for controlling S. litura is discussed.

G-protein beta-3 subunit C825T polymorphism, sodium and arterial blood pressure: a community-based study of Japanese men and women

Epidemiological evidence on gene-environment effects of the G-protein beta-3 subunit C825T polymorphisms and sodium on blood pressure in the free-living general population is limited. We examined the associations between the C825T polymorphism and blood pressure levels, stratified by the sodium variables estimated by 24-h urinary sodium excretion and a dietary questionnaire, among 1,471 men and women aged 30-74 from a community in Japan. Our a priori hypothesis was that individuals with the 825T allele have elevated blood pressure among subjects with a high sodium intake. Among the whole group, the systolic blood pressure level was +2.2 mmHg (p = 0.10) higher in TT than CC genotype individuals after adjustment for sex, age, antihypertensive medication use, body mass index, and alcohol consumption. This difference was more evident among individuals with low sodium excretion (+4.5 mmHg, p = 0.01), low present sodium intake (+3.2 mmHg, p = 0.11), and low past sodium intake (+4.8 mmHg, p = 0.02). No associations were observed among those with high sodium variables. Our results indicate that the G-protein beta-3 subunit C825T polymorphism is associated with higher systolic blood pressure levels in a large free-living Japanese population, and more specifically in women with a low sodium intake. This finding helps to explain part of the discrepancy between the previously reported genetic association among different ethnic groups.

The relationships of proteinuria, serum creatinine, glomerular filtration rate with cardiovascular disease mortality in Japanese general population

Proteinuria, high serum creatinine, and reduced glomerular filtration rate (GFR) have been associated with increased mortality from cardiovascular disease (CVD) and all causes. However, the combined effect of proteinuria with serum creatinine and GFR on CVD or all-cause mortality has not been well investigated. We conducted a 10-year prospective cohort study of 30,764 men and 60,668 women aged 40-79 years who participated in annual health checkups in 1993. The Cox proportional hazards model was used to estimate the relative risk (RR) after adjusting for age, smoking, and other cardiovascular risk factors. The multivariable RR (95% confidence interval (CI)) of CVD death for positive vs negative proteinuria was 1.38 (1.05-1.79) among men and 2.15 (1.64-2.81) among women. The respective RR for the highest vs lowest creatinine groups (> or = 1.3 vs < or = 0.8 mg/dl for men and > or = 1.1 vs < or = 0.6 mg/dl for women) was 1.56 (1.19-2.04) among men and 2.15 (1.58-2.93) among women. The respective RR for GFR < 60 vs > r = 100 ml/min/1.73 m2 was 1.65 (1.25-2.18) among men and 1.81 (1.39-2.36) among women. For individuals with proteinuria combined by hypercreatininemia or reduced GFR, the risk of CVD death was two-fold higher in men and 4-6-fold higher in women compared to those without proteinuria and with normal creatinine level or GFR. Similar associations were observed for stroke, coronary heart disease, and all-cause mortality. Proteinuria, and hypercreatininemia or reduced GFR and their combination were significant predictors of CVD and all-cause mortality.

Purification and properties of extracellular chitinases from the parasitic fungus Isaria japonica

Two chitinases (P-1 and P-2) induced with colloidal chitin were purified from the culture supernatant of Isaria japonica by chromatography on DEAE Bio-Gel, chromatofocusing and gel filtration with Superdex 75 pg. The enzymes were electrophoretically homogeneous and estimated to have a molecular mass of 43,273 (+/-5) for P-1 and 31,134 (+/-6) for P-2 by MALDI-MS. The optimum pH and temperature was 3.5-4.0 and 50 degrees C for P-1 and 4.0-4.5 and 40 degrees C for P-2. P-1 acted against chitosan 7B (degree of deacetylation, 65-74%) = glycol chitin > colloidal chitin = chitosan 10B (degree of deacetylation, above 99%) and P-2 against chitosan 7B > glycol chitin = chitosan 10B > colloidal chitin in order of activity. The products of hydrolysis of chitin and chitosan hexamer were analyzed by MALDI-MS. The products from the chitin hexamer obtained with P-1 were almost all dimers with only a small amount of trimer whereas those obtained with P-2 were mainly trimers with some dimer and tetramer. No hydrolysis of chitosan hexamer was observed. High homology in the amino-terminal sequence for chitinase P-1 was exhibited by chitinases from Trichoderma harzianum, Candida albicans and Saccharomyces cerevisiae in the range of 48-39%. The highest homology for Chitinase P-2 was shown by an endochitinase from Metarhizium anisopliae of 66%, while 44% homology was exhibited by chitinases of Leguminosae plants.

Type 2 diabetes and risk of non-embolic ischaemic stroke in Japanese men and women

AIMS/HYPOTHESIS

The aim of this study was to examine the relationship between type 2 diabetes and risk of ischaemic stroke in Asian populations.

METHODS

We conducted a 17-year prospective cohort study in 10,582 Japanese individuals (4287 men and 6295 women) aged 40-69 years living in five communities in Japan. All subjects were free of stroke and CHD at baseline. Diabetes was defined as a fasting glucose level of >/=7.0 mmol/l, a non-fasting glucose of >/=11.1 mmol/l, or receiving medication for diabetes.

RESULTS

The risk of non-embolic ischaemic stroke was approximately two-fold higher in diabetic subjects than in subjects with normal glucose levels. The multivariate relative risk after adjustment for age, community, hypertensive status, BMI, triceps and subscapular skinfold thickness (TSF and SSF), and other known cardiovascular risk factors was 1.8 (95% CI 1.0-3.2) for men and 2.2 (1.2-4.0) for women. This excess risk was primarily observed among non-hypertensive subjects and individuals with higher values for measures of adiposity (BMI, TSF and SSF values above the median), particularly those with higher values for SSF. The association between non-embolic ischaemic stroke and glucose abnormality was particularly strong among non-hypertensive subjects with higher SSF values: the multivariate relative risk was 1.9 (1.0-3.7) for borderline diabetes and 4.9 (2.5-9.5) for diabetes.

CONCLUSIONS/INTERPRETATION

In this cohort, type 2 diabetes was a significant risk factor for non-embolic ischaemic stroke, particularly in non-hypertensive and non-lean individuals. Due to the nationwide decrease in blood pressure and increase in mean BMI among the Japanese population, with current levels approaching those observed in Western countries, the impact of glucose abnormalities on risk of ischaemic stroke represents a forthcoming public health issue in Japan.

Obtusifoliol 14alpha-demethylase (CYP51) antisense Arabidopsis shows slow growth and long life

Obtusifoliol 14alpha-demethylase is a plant orthologue of sterol 14alpha-demethylase (CYP51) essential in sterol biosynthesis. We have prepared CYP51 antisense Arabidopsis in order to shed light on the sterol and steroid hormone biosynthesis in plants. Arabidopsis putative CYP51 cDNA (AtCYP51) was obtained from Arabidopsis expressed sequence tag (EST) library and its function was examined in a yeast lanosterol 14alpha-demethylase (Erg11) deficient mutant. A recombinant AtCYP51 protein fused with a yeast Erg11 signal-anchor peptide was able to complement the erg11 mutation, which confirmed AtCYP51 to be a functional sterol 14alpha-demethylase. AtCYP51 was then used to generate transgenic Arabidopsis by transforming with pBI vector harboring AtCYP51 in the antisense direction under CaMV35S promoter. The resulting transgenic plants were decreased in accumulation of AtCYP51 mRNA and increased in the amount of endogenous obtusifoliol. They showed a semidwarf phenotype in the early growth stage and a longer life span than control plants. This newly found phenotype is different from previously characterized brassinosteroid (BR)-deficient campesterol biosynthesis mutants.

Involvement of a nuclear-encoded basic helix-loop-helix protein in transcription of the light-responsive promoter of psbD

In the chloroplast psbD light-responsive promoter (LRP), a highly conserved sequence exists upstream from the bacterial -10/-35 elements. Multiple sequence-specific DNA binding proteins are predicted to bind to the conserved sequence as transcription factors. Using yeast one-hybrid screening of an Arabidopsis cDNA library, a possible DNA binding protein of the psbD LRP upstream sequence was identified. The protein, designated PTF1, is a novel protein of 355 amino acids (estimated molecular weight of 39.6) that contains a basic helix-loop-helix DNA binding motif in the predicted N-terminal region of the mature protein. Transient expression assay of PTF1-GFP fusion protein showed that PTF1 was localized in chloroplasts. Using the modified DNA sequence in the one-hybrid system, the ACC repeat was shown to be essential for PTF1 binding. The rate of psbD LRP mRNA accumulation was reduced in a T-DNA-inserted Arabidopsis ptf1 mutant. Compared with wild-type plants, the mutant had pale green cotyledons and its growth was inhibited under short-day conditions. These results suggest that PTF1 is a trans-acting factor of the psbD LRP.

Characterization of brassinazole, a triazole-type brassinosteroid biosynthesis inhibitor

Screening for brassinosteroid (BR) biosynthesis inhibitors was performed to find chemicals that induce dwarfism in Arabidopsis, mutants that resembled BR biosynthesis mutants that can be rescued by BR. Through this screening experiment, the compound brassinazole was selected as the most potent chemical. In dark-grown Arabidopsis, brassinazole-induced morphological changes were nearly restored to those of wild type by treatment with brassinolide. The structure of brassinazole is similar to pacrobutrazol, a gibberellin biosynthesis inhibitor. However, in assays with cress (Lepidium sativum) plants, brassinazole-treated plants did not show recovery after the addition of gibberellin but showed good recovery after the addition of brassinolide. These data demonstrate that brassinazole is a specific BR biosynthesis inhibitor. Brassinazole-treated cress also showed dwarfism, with altered leaf morphology, including the downward curling and dark green color typical of Arabidopsis BR-deficient mutants, and this dwarfism was reversed by the application of 10 nM brassinolide. This result suggests that BRs are essential for plant growth, and that brassinazole can be used to clarify the function of BRs in plants as a complement to BR-deficient mutants. The brassinazole action site was also investigated by feeding BR biosynthesis intermediates to cress grown in the light.

Development of a new inhibitor of glucosylceramide synthase

Analogs of the potent inhibitor of glucosylceramide (GlcCer) synthase, D-threo-1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4), based on substitutions in the palmitoyl group were made by means of a stereo-selective synthetic method in order to elucidate the role of the hydrophobic portion in both the inhibitory action toward the enzyme and the biological effects. While P4 strongly inhibited GlcCer synthase with an IC(50) of 0.5 microM in vitro, it also inhibited cell growth by 50% at the concentration of 7 microM. The shorter N-acyl chain analogs including decanoyl, octanoyl, and hexanoyl groups showed similar IC(50) values for GlcCer synthase (around 2 microM) but the hexanoyl analog exhibited only a slight inhibitory effect on cell growth, showing the dissociation between GlcCer depletion and cell growth. Several compounds which exhibit similar hydrophobicity to the hexanoyl analog of P4 were subsequently designed. We found that D-threo-1-phenyl-2-benzyloxycarbonylamino-3-pyrrolidino-1-pr opanol (PBPP) was a most potent inhibitor, showing an IC50 of 0.3 microM. In cultured cells, PBPP was able to deplete glycosphingolipids without affecting cell growth or the ceramide level.

Molecular architecture of the mouse DNA polymerase alpha-primase complex

The DNA polymerase alpha-primase complex is the only enzyme that provides RNA-DNA primers for chromosomal DNA replication in eukaryotes. Mouse DNA polymerase alpha has been shown to consist of four subunits, p180, p68, p54, and p46. To characterize the domain structures and subunit requirements for the assembly of the complex, we constructed eukaryotic polycistronic cDNA expression plasmids expressing pairwise the four subunits of DNA polymerase alpha. In addition, the constructs contained an internal ribosome entry site derived from poliovirus. The constructs were transfected in different combinations with vectors expressing single subunits to allow the simultaneous expression of three or four of the subunits in cultured mammalian cells. We demonstrate that the carboxyl-terminal region of p180 (residues 1235 to 1465) is essential for its interaction with both p68 and p54-p46 by immunohistochemical analysis and coprecipitation studies with antibodies. Mutations in the putative zinc fingers present in the carboxyl terminus of p180 abolished the interaction with p68 completely, although the mutants were still capable of interacting with p54-p46. Furthermore, the amino-terminal region (residues 1 to 329) and the carboxyl-terminal region (residues 1280 to 1465) were revealed to be dispensable for DNA polymerase activity. Thus, we can divide the p180 subunit into three domains. The first is the amino-terminal domain (residues 1 to 329), which is dispensable for both polymerase activity and subunit assembly. The second is the minimal core domain (residues 330 to 1279), required for polymerase activity. The third is the carboxyl-terminal domain (residues 1280 to 1465), which is dispensable for polymerase activity but required for the interaction with the other three subunits. Taken together, these results allow us to propose the first structural model for the DNA polymerase alpha-primase complex in terms of subunit assembly, domain structure, and stepwise formation at the cellular level.

Perception of dioxin and other risks in Japan: replication and extension

Previous research has shown that the common understanding of risk may be expressed by factor-analytic models that represent how fatal are risks and how voluntarily one assumes such threats. We investigated whether a similar representation would model Japanese participants' risk perception. Moreover, because Japanese newscasts concentrated their coverage exclusively on dioxin during the period of this research, we expected that those who were exposed to such newscasts would more frequently develop greater environmental awareness. We also examined whether this "news-exposed group's" knowledge about dioxin was consistent with the known facts regarding dioxin. Analysis showed that the two factors adequately modeled the Japanese sample's risk representation (N = 473) and that the news-exposed group (n = 188) did exhibit higher environmental awareness. Implications for risk research are discussed.