Energy Expenditure in Free-Living Japanese People with Obesity and Type 2 Diabetes, Measured Using the Doubly-Labeled Water Method

We determined the total energy expenditure (TEE) of healthy overweight or obese people, and those with impaired glucose tolerance and/or impaired fasting glycemia (IGT/IFG), or type 2 diabetes (T2DM) using the doubly-labeled water method. As a second purpose, we compared the measured TEE with the target energy intake recommended in the treatment guidelines for diabetes. The participants were normal glucose tolerance (NGT), and IGT/IFG (n=11) and T2DM (n=9) patients, who were 50-59 y and had a body mass index >25 kg/m². The median TEE/body mass (BM) values were 32.6, 33.3, and 34.4 kcal/kg BM and the TEE/target BM values (target BM: BM at a BMI of 22 kg/m²) were 43.7, 50.2, and 46.5 kcal/kg target BM for each group, respectively, and did not differ significantly among them. Obese Japanese participants with T2DM in this study had lower TEE/BM than previously studied in non-obese participants with T2DM. In IGT/IFG or T2DM patients, if 30 kcal/kg target BM was used as the energy coefficient, on the basis of the treatment guidelines, the difference between TEE and the target energy intake would be -1,174±552 kcal (-38±11%). When 35 kcal/kg target BM was used as the energy coefficient, the difference between TEE and the target energy intake would be -877±542 kcal (-27±13%). Thus, the energy coefficients used to estimate target energy intake during lifestyle modification in obese/overweight patients with T2DM are considered to be quite low during the first step of diet therapy.

Vegetable Intake at Breakfast and Associated Factors among Young Adults in Japan

In Japan, the amount of vegetable intake in young adults, especially at breakfast, is low. We aimed to examine the factors associated with vegetable intake at breakfast among young adults. In 2016, a self-administered questionnaire survey was conducted at a Japanese university. The questionnaire measured the frequency of ≥70 g vegetable intake at breakfast, lifestyle, eating habits, environmental factors, knowledge and attitudes (including the variable "Perceived behavior control (PBC)", from the Theory of Planned Behavior). The data of 1,455 male students who usually ate breakfast were analyzed. They were divided into two groups based on the median of the frequency of vegetable intake and the above factors were compared using a chi-squared test by living condition. The significant factors were subsequently entered into a logistic regression analysis as independent variables. Eating breakfast with family or friends and PBC were positively associated with vegetable intake in students living with their family. Often doing one's own cooking, having knowledge about a well-balanced diet, and PBC were positively associated with vegetable intake in students living alone. Along with PBC, different factors pertaining to an individual's living condition may need to be considered to increase vegetable intake at breakfast.

Decreased number of days of fever detection and duration of fever with continuous intake of a fermented milk drink: a randomized, double-blind, placebo-controlled study of elderly nursing home residents

We conducted a randomized, double-blind, placebo-controlled parallel study to investigate the effects of a fermented milk on elderly nursing home residents. Eighty-eight participants each drank one bottle of fermented milk containing Lactobacillus casei strain Shirota, or a placebo, on a daily basis for 6 months in winter. Peripheral blood, saliva, fecal samples, and clinical data were analyzed to assess the milk’s efficacy. Fermented milk consumption was associated with a significant decrease in the number of days on which fever was detected and the mean duration of fever compared with these values in the placebo group. No significant differences were observed in other biological parameters. Continuous intake of this fermented milk could be beneficial for the elderly in terms of suppressing the number of days of detection of fever and the duration of fever, which usually increase in winter.

Effects of 1-year weight loss intervention on abdominal skeletal muscle mass in Japanese overweight men and women

BACKGROUND AND OBJECTIVES

Limited information is available on how weight loss intervention programs affect skeletal muscle mass especially in trunk.

METHODS AND STUDY DESIGN

A total of 235 overweight Japanese men and women aged 40-64 years with a body mass index of 28.0 to 44.8 kg/m2 participated in this randomized controlled intervention study. They were randomly divided into a lifestyle intervention group and control group. Before and after the one-year lifestyle intervention for weight loss an abdominal transverse image was acquired by computed tomography. The cross-sectional areas (CSAs) of visceral fat, subcutaneous fat, and skeletal muscle of rectus abdominis, abdominal oblique, iliopsoas, and erector spinae muscle were calculated.

RESULTS

The body weight changed by approximately -5% in the intervention groups. The corresponding values for subcutaneous fat and visceral fat CSAs were -10.8 to -17.5% in both sexes. The reductions observed in skeletal muscle CSAs were significantly less (-6.0% and -7.2% in the men and women intervention groups respectively) than those in fat tissue CSAs. The CSA of each of the four skeletal muscle groups also significantly decreased; however, after adjustments for body weight at each time point, only reductions in the iliopsoas muscle in both sex and abdominal oblique muscles in men remained significant.

CONCLUSIONS

The lifestyle weight loss intervention might reduce the relative amount of the abdominal skeletal muscles especially in iliopsoas muscle.

[Cross-sectional association of the number of neighborhood facilities assessed using postal code with objectively measured physical activity: the Saku cohort study]

Objectives The aim of this study was to examine the association between the number of neighborhood facilities that were assessed according to postal code and objectively measured physical activity by using an accelerometer in community-dwelling Japanese people.Methods The participants included 1,274 Japanese people aged 30-84 years from the Saku cohort study. As neighborhood facilities related to physical activity, we extracted information regarding train stations, supermarkets/convenience stores, postal offices/banks, hospitals/clinics, public offices/community centers, cultural facilities/public children's houses, parks, and sports facilities by using each participant's postal code from the online version of the iTownPages directory published by Nippon Telegraph and Telephone Corporation (NTT) and the official homepage of the Saku City Government Office. We measured each participant's physical activity level using an accelerometer, and calculated the average daily step count and the average weekly period of moderate-to-vigorous intensity (≥3 metabolic equivalents of tasks [METs]) physical activity. The association between two selected physical activity-related variables and the numbers of eight types of neighborhood facilities were analyzed by multivariate logistic regression analysis for people aged 30-64 years and for those aged over 65 years.Results On multivariate logistic regression analysis, meeting the 23 METs h/week of moderate-to-vigorous intensity physical activity was significantly and positively associated with the number of supermarkets/convenience stores in the neighborhood in both age groups. In addition, meeting the desired daily step count outlined in the Japanese National Health Promotion guidelines was positively related to the number of postal offices/banks for people aged over 65 years.Conclusion The results of this study suggest that a sufficient number of neighborhood facilities (i.e., stores, banks, and postal offices) is closely associated with the promotion of physical activity.

Perceptions and practices of commensality and solo-eating among Korean and Japanese university students: A cross-cultural analysis

BACKGROUND/OBJECTIVES

Commensality, eating together with others, is a major representation of human sociality. In recent time, environments around commensality have changed significantly due to rapid social changes, and the decline of commensality is perceived as a serious concern in many modern societies. This study employs a cross-cultural analysis of university students in two East Asian countries, and examines cross-cultural variations of perceptions and actual practices of commensality and solo-eating.

SUBJECTS/METHODS

The analysis was drawn from a free-list survey and a self-administrative questionnaires of university students in urban Korea and Japan. The free-listing survey was conducted with a small cohort to explore common images and meanings of commensality and solo-eating. The self-administrative questionnaire was developed based on the result of the free-list survey, and conducted with a larger cohort to examine reasons and problems of practices and associated behaviors and food intake.

RESULTS

We found that Korean subjects tended to show stronger associations between solo-eating and negative emotions while the Japanese subjects expressed mixed emotions towards the practice of solo-eating. In the questionnaire, more Korean students reported they prefer commensality and tend to eat more quantities when they eat commensally. In contrast, more Japanese reported that they do not have preference on commensality and there is no notable difference in food quantities when they eat commensally and alone. Compared to the general Korean cohort finding, more proportion of overweight and obese groups of Korean subjects reported that they tend to eat more when they are alone than normal and underweight groups. This difference was not found in the overweight Japanese subjects.

CONCLUSION

Our study revealed cross-cultural variations of perceptions and practices of commensality and solo-eating in a non-western setting.

Tks5 activation in mesothelial cells creates invasion front of peritoneal carcinomatosis

Scirrhous gastric cancer is frequently associated with peritoneal dissemination, and the interaction of cancer cells with peritoneal mesothelial cells (PMCs) is crucial for the establishment of the metastasis in the peritoneum. Although cells derived from PMCs are detected within tumors of peritoneal carcinomatosis, how PMCs are incorporated into tumor architecture is not understood. The present study shows that PMCs create the invasion front of peritoneal carcinomatosis, which depends on activation of Tks5 in PMCs. In peritoneal tumor implants, PMCs represent majority of cells located at the invasive edge of the cancer tissue. Exogenously implanted PMCs and host PMCs aggressively invade into abdominal wall upon the peritoneal inoculation of cancer cells, and PMCs locate ahead of cancer cells in the direction of invasion. Tks5, a substrate of Src kinase, is predominantly expressed in the PMCs of cancer tissue, and promotes the invasion of PMCs and cancer cells. Expression and activation of Tks5 was induced in PMCs following their exposure to gastric cancer cells, and increased Tks5 expression was detected in PMCs located at the invasion front. Reduced Tks5 expression in PMCs blocked PMC invasion, which in turn prevents cancer cell invasion both in vitro and in vivo. The peritoneal dissemination of gastric cancer was significantly increased by mixing cancer cells and PMCs, and was suppressed by knockdown of Tks5 in PMCs. These results suggest that cancer-activated PMCs create invasion front by guiding cancer cells. Signaling leading to Tks5 activation in PMCs may be a suitable therapeutic target for prevention of peritoneal carcinomatosis.

Preproghrelin gene polymorphisms in obese Japanese: Association with diabetes mellitus in men and with metabolic syndrome parameters in women

SUMMARY

Preproghrelin gene polymorphisms (SNPs) are possible predisposing factors to obesity and metabolic syndrome. We analysed SNPs in obese Japanese individuals and studied the correlation with diabetes and metabolic syndrome. We recruited 235 subjects (BMI > 28.3) from individuals undergoing periodic medical check-up at Saku Central Hospital. Their SNPs were genotyped using PCR-RFLP method. Frequencies of 5 SNPs in the preproghrelin gene -1500C>G (rs3755777), -1062G>C (rs26311), -994C>T (rs26312), Leu72Met (+408C>A) (rs696217), and +3056T>C (rs2075356) were compared with healthy individuals (data from HapMap Project or Asian population studies). Associations between these SNPs and clinical parameters were investigated. The phenotypes evidently differed between men and women. In men, higher fasting glucose and HbA1c values were observed in the +3056C/C minor homozygotes without leptin or insulin accumulation. The +408C -- +3056C haplotype was more frequent in the diabetic subgroup, in which diagnosis was based on fasting glucose, 75gOGTT, and HbA1c values, than normal subgroup. In contrast, in women, a significant correlation was observed between fat metabolism and obesity. The -1062C/C minor homozygotes had higher values of C-peptide, insulin, total and visceral fat area, waist circumference and BMI. The 72Met/Met minor homozygotes showed reduced leptin, total, HDL and LDL cholesterol concentrations and increased value of visceral fat area. Further, in the other SNPs, the minor homozygotes showed a similar trend, and the heterozygotes had intermediate values. Preproghrelin gene polymorphisms in obese Japanese may be predisposing factors to diabetes mellitus in men and to obesity via aberrant fat metabolism in women.:

Low-molecular-weight adiponectin and high-molecular-weight adiponectin levels in relation to diabetes

OBJECTIVE

To evaluate the association between adiponectin complexes (high-molecular-weight [HMW], middle-molecular-weight [MMW], and low-molecular-weight [LMW] adiponectin) and diabetes.

DESIGN AND METHODS

We conducted a case-control study, based on a cohort in Saku, Japan. Among 2565 participants, 300 participants with diabetes and 300 matched controls (430 men and 170 women) were analyzed.

RESULTS

After adjusting for age, physical activity, hypertension, family history, alcohol use, smoking, and menopausal status, total, HMW, and LMW, but not MMW adiponectin levels were inversely associated with diabetes: total adiponectin, odds ratio comparing the highest with the lowest quartiles, 0.46 (95% confidence interval, 0.25-0.82; P for trend = 0.046); HMW, 0.40 (95%CI, 0.22-0.72; P = 0.046); MMW, 1.04 (95%CI, 0.60-1.77; P = 0.81); and LMW, 0.51 (95%CI, 0.29-0.89; P = 0.01). The associations between total and HMW adiponectin and diabetes attenuated after adjustment for BMI (P = 0.15 and 0.13, respectively), but LMW remained (P = 0.04). When stratified by sex, LMW adiponectin levels were associated with diabetes in men only. None of the associations were significant after adjustment for HOMA-IR.

CONCLUSIONS

Decreased LMW, total, and HMW adiponectin levels are associated with diabetes. These associations may be secondary to adiposity or insulin resistance.

Asporin activates coordinated invasion of scirrhous gastric cancer and cancer-associated fibroblasts

Scirrhous gastric cancer, which has the worst prognosis among the various types of gastric cancer, is highly invasive and associated with abundant stromal fibroblasts. Although cancer-associated fibroblasts (CAFs) have been proposed to generate a tumor-supportive extracellular matrix that promotes the expansion of this type of cancer, the molecular mechanisms by which CAFs assist cancer cells are not yet fully understood. Here, we show for the first time that Asporin, a small leucine-rich proteoglycan (SLRP), is predominantly expressed in CAFs, and has essential roles in promoting co-invasion of CAFs and cancer cells. CAFs of scirrhous gastric cancer possess high potential for invasion, and invasion by CAFs frequently proceeded invasion by cancer cells, both in vitro and in vivo. Expression of Asporin was induced in fibroblasts by exposure to gastric cancer cells. Asporin secreted from CAFs activates Rac1 via an interaction with CD44 and promotes invasion by CAFs themselves. Moreover, Asporin promoted invasion by neighboring cancer cells, via paracrine effects mediated by activation of the CD44-Rac1 pathway. These results suggest that Asporin is a unique SLRP that promotes progression of scirrhous gastric cancer and is required for coordinated invasion by CAFs and cancer cells. Therefore, Asporin may represent a new therapeutic target molecule for the development of drugs aimed at manipulating the cancer microenvironment.

Validity of diabetes self-reports in the Saku diabetes study

BACKGROUND

Diabetes is an important risk factor for cardiovascular disease, certain types of cancer, and death, and self-reports are one of the most convenient methods for ascertaining diabetes status. We evaluated the validity of diabetes self-reports among Japanese who participated in a health checkup.

METHODS

Self-reported diabetes was cross-sectionally compared with confirmed diabetes among 2535 participants aged 28 to 85 years in the Saku cohort study. Confirmed diabetes was defined as the presence of at least 1 of the following: fasting plasma glucose (FPG) level of 126 mg/dL or higher, 2-hour post-load glucose (2-hPG) level of 200 mg/dL or higher after a 75-gram oral glucose tolerance test, glycated hemoglobin (HbA1c) level of 6.5% or higher, or treatment with hypoglycemic medication(s).

RESULTS

Of the 251 participants with self-reported diabetes, 121 were taking hypoglycemic medication(s) and an additional 69 were classified as having diabetes. Of the 2284 participants who did not self-report diabetes, 80 were classified as having diabetes. These data yielded a sensitivity of 70.4%, a specificity of 97.3%, a positive predictive value of 75.7%, and a negative predictive value of 96.5%. The frequency of participants with undiagnosed diabetes was 3.0%. Of these, 64.2% had FPG within the normal range and were diagnosed by 2-hPG and/or HbA1c.

CONCLUSIONS

Our findings provide additional support for the use of self-reported diabetes as a measure of diabetes in epidemiologic studies performed in similar settings in Japan if biomarker-based diagnosis is difficult.

Reduction in adiposity, β-cell function, insulin sensitivity, and cardiovascular risk factors: a prospective study among Japanese with obesity

Background

A reduction in adiposity may be associated with an improvement in insulin sensitivity and β-cell function as well as cardiovascular disease (CVD) risk factors; however, few studies have investigated these associations in a longitudinal setting.

Methods

To investigate these associations over a 1-year period, we conducted an observational analysis of 196 Japanese subjects with obesity in the Saku Control Obesity Program. We investigated the relations between changes in adiposity (body mass index [BMI], waist circumference, subcutaneous fat area [SFAT], and visceral fat area [VFAT]) and changes in HbA1c, fasting plasma glucose (FPG), insulin sensitivity index (ISI), the homeostasis model assessment β cell function (HOMA-β), lipids, and blood pressure.

Results

All adiposity changes were positively associated with HbA1c and FPG changes. Reductions in BMI and VFAT were associated with HOMA-β reduction. Reductions in all adiposity measures were associated with an improvement in the ISI. Changes in most adiposity measures were positively associated with changes in blood pressure and lipid levels, except for LDL.

Conclusion

The present findings provide additional supportive evidence indicating that a reduction in adiposity may lead to an improvement in insulin sensitivity and the reduction of CVD risk factors in obese individuals.

Associations of sex hormone-binding globulin and testosterone with diabetes among men and women (the Saku Diabetes study): a case control study

BACKGROUND

Sex hormone-binding globulin (SHBG) levels and sex hormones have been implicated in the pathogenesis of type 2 diabetes and cardiovascular diseases. As fatty liver has been suggested to be a major determinant of SHBG levels, we examined whether the associations of SHBG and testosterone with diabetes were independent of fatty liver.

METHODS

We conducted a case-control study that included 300 diabetes cases (215 men and 85 women) and 300 matched controls from the Saku cohort study. Diabetes was defined by either fasting plasma glucose levels ≥126 mg/dL, 2-h post-load glucose levels ≥200 mg/dL after a 75 g oral glucose tolerance test, or diabetes diagnosed by physicians. We fitted conditional logistic regression models to examine the associations between SHBG and total testosterone levels with diabetes by sex. To evaluate the impact of fatty liver, we used the fatty liver index (FLI), a validated measure derived from serum triglyceride levels, body mass index (BMI), waist circumference, and γ-glutamyltransferase levels.

RESULTS

After adjusting for age, family history of diabetes, smoking, physical activity, BMI, and FLI, SHBG levels were inversely associated with diabetes among women (odds ratio [OR] comparing the highest with the lowest quartiles, 0.13 [95% confidence interval {CI}, 0.02-0.96]), but not among men. Similar patterns were observed in a subgroup analysis restricted to postmenopausal women"(OR, 0.12 [95% CI, 0.01-1.17]). In contrast, testosterone levels were inversely associated with diabetes among men (OR, 0.45 [95% CI, 0.23-0.89]), but not among women.

CONCLUSIONS

Our findings suggest that SHBG in women and testosterone in men may be inversely associated with diabetes.

Dietary glycemic index and glycemic load in relation to HbA1c in Japanese obese adults: a cross-sectional analysis of the Saku Control Obesity Program

BACKGROUND

Dietary glycemic index or load is thought to play an important role in glucose metabolism. However, few studies have investigated the relation between glycemic index (GI) or load (GL) and glycemia in Asian populations. In this cross-sectional analysis of a randomized controlled trial, the Saku Control Obesity Program, we examined the relation between the baseline GI or GL and glycemia (HbA1c and fasting plasma glucose [FPG] levels), insulin resistance (HOMA-IR), β-cell function (HOMA-β), and other metabolic risk factors (lipid levels, diastolic and systolic blood pressure, and adiposity measures).

METHODS

The participants were 227 obese Japanese women and men. We used multiple linear regression models and logistic regression models to adjust for potential confounding factors such as age, sex, visceral fat area, total energy intake, and physical activity levels.

RESULTS

After adjustments for potential confounding factors, GI was not associated with HbA1c, but GL was positively associated with HbA1c. For increasing quartiles of GI, the adjusted mean HbA1c were 6.3%, 6.7%, 6.4%, and 6.4% (P for trend = 0.991). For increasing quartiles of GL, the adjusted mean HbA1c were 6.2%, 6.2%, 6.6%, and 6.5% (P for trend = 0.044). In addition, among participants with HbA1c ≥ 7.0%, 20 out of 28 (71%) had a high GL (≥ median); the adjusted odds ratio for HbA1c ≥ 7.0% among participants with higher GL was 3.1 (95% confidence interval [CI] = 1.2 to 8.1) compared to the participants with a lower GL (

CONCLUSIONS

Our findings suggest that participants with poor glycemic control tend to have a higher GL in an obese Japanese population.

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What behaviors are important for successful weight maintenance?

Purpose. To examine behavioral factors related to successful weight maintenance. Methods. Subjects were 90 middle-aged participants who attended a weight loss program and were followed for one year. The subjects were classified into either successful weight maintainers (maintained a weight loss of 5% or more from their initial weight for one year) (SWM) or unsuccessful weight maintainers (USWM), and weight control practice, stress, obstacles, support, and self-efficacy during the program and follow-up period were compared. Results. SWM had mean loss of 12% from their initial weight during the program. They showed a greater improvement in their regularity of eating, walked more, and felt less stress regarding their increased physical activity than the USWM. During the follow-up period, significantly more SWM participants had self-efficacy (for measuring weight, practicing dietary objective, and assessing the practice and keeping records), actually kept records and measured weight more than the USWM participants. In contrast, more USWM participants felt stress about measuring weight. Conclusion. In addition to a substantial initial weight loss due to an increased amount of physical activity, having a higher self-efficacy and consistently keeping records of one's activities, as well as regularly weighing themselves, may be important for successful weight maintenance.

Behavioral change during weight loss program and one-year follow-up: Saku Control Obesity Program (SCOP) in Japan

This study evaluated effects of a behavioral approach which placed emphasis on tailored behavior counseling, diet, weight loss and weight maintenance. A one-year randomized controlled trial was conducted among 235 overweight/obese adults in Japan. The intervention group (n=119) received individual-based counseling using a behavioral approach and the changes made in the diet and physical activity were dependent on each participant as much as possible. One year later, the intervention group lost significantly more weight than the control group (-5.0 kg vs. 0.1 kg for men and -3.9 kg vs. -0.2 kg for women). Compared to the control group, the male intervention group reduced overall energy, cereals and dairy products consumption significantly, while increasing green and yellow vegetable intake, and the female intervention group significantly reduced intake of dairy products. Regarding behaviors, both male and female intervention groups increased the number of walking steps and women improved their irregular eating habits compared to those in the control groups. Behavior changes were related to weight loss; participants who maintained the action/maintenance stage or moved to later stages lost significantly more weight than participants who remained in the pre-contemplation/contemplation/preparation stages or regressed to earlier stages. After one-year follow-up, the intervention group maintained significantly lower weights, lower energy intakes and improvements in irregular eating habits. Our behavioral approach led to diet and behavior modification, weight loss and maintenance. Because modified variables differed between men and women, gender-specific approaches may be necessary.

Caffeine abolishes the ultraviolet-induced REV3 translesion replication pathway in mouse cells

When a replicative DNA polymerase stalls upon encountering a photoproduct on the template strand, it is relieved by other low-processivity polymerase(s), which insert nucleotide(s) opposite the lesion. Using an alkaline sucrose density gradient sedimentation technique, we previously classified this process termed UV-induced translesion replication (UV-TLS) into two types. In human cancer cells or xeroderma pigmentosum variant (XP-V) cells, UV-TLS was inhibited by caffeine or proteasome inhibitors. However, in normal human cells, the process was insensitive to these reagents. Reportedly, in yeast or mammalian cells, REV3 protein (a catalytic subunit of DNA polymerase ζ) is predominantly involved in the former type of TLS. Here, we studied UV-TLS in fibroblasts derived from the Rev3-knockout mouse embryo (Rev3KO-MEF). In the wild-type MEF, UV-TLS was slow (similar to that of human cancer cells or XP-V cells), and was abolished by caffeine or MG-262. In 2 cell lines of Rev3KO-MEF (Rev3^−/−p53^−/−), UV-TLS was not observed. In p53KO-MEF, which is a strict control for Rev3KO-MEF, the UV-TLS response was similar to that of the wild-type. Introduction of the Rev3 expression plasmid into Rev3KO-MEF restored the UV-TLS response in selected stable transformants. In some transformants, viability to UV was the same as that in the wild-type, and the death rate was increased by caffeine. Our findings indicate that REV3 is predominantly involved in UV-TLS in mouse cells, and that the REV3 translesion pathway is suppressed by caffeine or proteasome inhibitors.

Rev1, Rev3, or Rev7 siRNA Abolishes Ultraviolet Light-Induced Translesion Replication in HeLa Cells: A Comprehensive Study Using Alkaline Sucrose Density Gradient Sedimentation

When a replicative DNA polymerase stalls upon encountering a lesion on the template strand, it is relieved by other low-processivity polymerase(s), which insert nucleotide(s) opposite the lesion, extend by a few nucleotides, and dissociate from the 3'-OH. The replicative polymerase then resumes DNA synthesis. This process, termed translesion replication (TLS) or replicative bypass, may involve at least five different polymerases in mammals, although the participating polymerases and their roles have not been entirely characterized. Using siRNAs originally designed and an alkaline sucrose density gradient sedimentation technique, we verified the involvement of several polymerases in ultraviolet (UV) light-induced TLS in HeLa cells. First, siRNAs to Rev3 or Rev7 largely abolished UV-TLS, suggesting that these 2 gene products, which comprise Polζ, play a main role in mutagenic TLS. Second, Rev1-targeted siRNA also abrogated UV-TLS, indicating that Rev1 is also indispensable to mutagenic TLS. Third, Polη-targeted siRNA also prevented TLS to a greater extent than our expectations. Forth, although siRNA to Polι had no detectable effect, that to Polκ delayed UV-TLS. To our knowledge, this is the first study reporting apparent evidence for the participation of Polκ in UV-TLS.

Observation of an energetic-particle-driven instability in the wall-stabilized high-beta plasmas in the JT-60U tokamak

We have observed a bursting mode in the high-beta plasmas above the ideal beta limit without a conducting wall. The mode frequency is chirping down as the mode amplitude increases, and its initial value is close to the precession frequency of the trapped energetic particle from the perpendicular neutral beams. The mode structure is radially extended with a peak around the q = 2 surface. This mode can finally trigger the resistive wall mode (RWM) despite enough plasma rotation for RWM stabilization. It is concluded that the mode is driven by trapped energetic particles. The mode is attributed to the interaction between the trapped energetic particles and a marginally stable mode in the wall-stabilized high-beta_{N} region.