Issei Kurahashi

Impact of expression of human epidermal growth factor receptors EGFR and ERBB2 on survival in stage II/III gastric cancer.

Purpose: EGF receptor (EGFR) and HER2 positivity are considered to be negative prognostic factors in gastric cancer. Biomarker analysis was conducted to evaluate the impact of EGFR and HER2 expression on the outcome of patients enrolled in the Adjuvant Chemotherapy Trial of TS-1 for Gastric Cancer (ACTS-GC), a randomized controlled trial comparing postoperative adjuvant S-1 therapy with surgery alone in 1,059 patients with stage II/III gastric cancer. Experimental Design: Formalin-fixed, paraffin-embedded surgical specimens were retrospectively examined in 829 patients (78.3%). The effects of EGFR and HER2 positivity on survival were analyzed on the basis of the 5-year survival data from the study. EGFR positivity was defined as an immunohistochemistry (IHC) score of 3+, and HER2 positivity as an IHC score of 3+ or an IHC score of 2+ with a positive dual-color in situ hybridization status. Results: EGFR and HER2 were positive in 75 (9.0%) and 113 (13.6%) patients, respectively. The overall and relapse-free survival rates were significantly lower in EGFR-positive patients than in EGFR-negative patients, whereas they were similar in HER2-positive and HER2-negative patients. Multivariate analysis showed that EGFR positivity correlated with poor outcomes [HR = 1.504; 95% confidence interval (CI) = 1.020–2.149; P = 0.040]. Treatment with S-1 improved survival compared with surgery alone, irrespective of EGFR and HER2 status. Conclusions: EGFR positivity, but not HER2 positivity, was associated with poor patient outcomes after curative resection of stage II/III gastric cancer. There was no interaction between S-1 and EGFR or HER2 status with respect to survival outcome. Clin Cancer Res; 18(21); 5992–6000. ©2012 AACR.

Association between prehypertension and chronic kidney disease in the Japanese general population

The increased prevalence of chronic kidney disease (CKD) is a consequence of the accumulation of risk factors, one of which is hypertension. Here we assessed the prevalence of CKD according to blood pressure among 232,025 patients in a Japanese nationwide database with a focus on the prevalence and risk factors of CKD in prehypertension. Patients were stratified by blood pressure and included 75,474 with optimal blood pressure (less than 120/80 mm Hg); 59,194 with prehypertension and a normal blood pressure (120-129/80-84 mm Hg) or 46,547 patients with high-normal blood pressure (130-139/85-89 mm Hg); and 50,810 with hypertension (over 140/90 mm Hg without anti-hypertensive drugs). CKD was defined as an estimated glomerular filtration rate of stage 3 or lower or having proteinuria greater than 1+ by a dipstick method. The prevalence of CKD among patients with optimal blood pressure, prehypertension having normal or high-normal blood pressure, and hypertension was 13.9, 15.6, 18.1, and 20.7% in men, and 10.9, 11.6, 12.9, and 15.0% in women, with a significant difference between genders at each strata of blood pressure. In men, but not in women, whose blood pressure was high-normal, the CKD risk was significantly greater (odds ratio 1.11) than those with optimal blood pressure. Obesity (body mass index over 25) was significantly associated with an increased risk of CKD in both men and women (odds ratio 1.43 and 1.26, respectively), and there was an additive effect of obesity and pre-hypertension on CKD risk in men compared with men with optimal blood pressure. Thus, the prevalence of CKD increased with the severity of blood pressure. Prehypertension with high-normal blood pressure, particularly in conjunction with obesity, was found to be an independent risk factor of CKD in men.

Association of the triglycerides to high-density lipoprotein cholesterol ratio with the risk of chronic kidney disease: Analysis in a large Japanese population

OBJECTIVES To investigate the relationship between triglycerides to high-density lipoprotein cholesterol ratio (TG/HDL-C) and chronic kidney disease (CKD). METHODS We used data from 216,007 Japanese adults who participated in a nationwide health checkup program. Men (n = 88,516) and women (n = 127,491) were grouped into quartiles based on their TG/HDL-C levels (<1.26, 1.26-1.98, 1.99-3.18, and >3.18 in men; <0.96, 0.96-1.44, 1.45-2.22, and >2.22 in women). We cross-sectionally assessed the association of TG/HDL-C levels with CKD [defined as an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m(2) (low eGFR) and/or proteinuria (defined as urinary protein ≥ 1+ on dipstick testing)], low eGFR, and proteinuria. RESULTS The prevalence of CKD, low eGFR, and proteinuria increased significantly with elevating quartiles of TG/HDL-C in both genders (all P for trend <0.001). Participants in the highest quartile of TG/HDL-C had a significantly greater risk of CKD than those in the lowest quartile after adjustment for the relevant confounding factors (odds ratio: 1.57, 95% confidence interval: 1.49-1.65 in men; 1.41, 1.34-1.48 in women, respectively). Furthermore, there were significant associations with low eGFR and proteinuria. In stratified analysis, the risk of CKD increased linearly with greater TG/HDL-C levels in participants with and without hypertension, diabetes, and obesity. Moreover, higher TG/HDL-C levels were relevant for CKD, especially in participants with hypertension and diabetes (P for interaction <0.001, respectively). CONCLUSIONS An elevated TG/HDL-C is associated with the risk of CKD in the Japanese population.

Long-Term Blood Pressure Variability, New-Onset Diabetes Mellitus, and New-Onset Chronic Kidney Disease in the Japanese General Population

Whether long-term blood pressure (BP) variability among individuals without diabetes mellitus is associated with new-onset chronic kidney disease (CKD) risk, independently of other BP parameters (eg, mean BP, cumulative exposure to BP) and metabolic profile changes during follow-up, remains uncertain. We used data from a nationwide study of 48 587 Japanese adults aged 40 to 74 years (mean age, 61.7 years; 39% men) without diabetes mellitus or CKD (estimated glomerular filtration rate <60 mL/min per 1.73 m2 or proteinuria by dipstick). BP was measured at baseline and during 3 annual follow-up visits (4 visits). BP variability was defined as standard deviation (SD) and average real variability during the 4 visits. At the year 3 follow-up visit, 6.3% of the population had developed CKD. In multivariable-adjusted logistic regression models, 1 SD increases in SDSBP (per 5 mmHg), SDDBP (per 3 mmHg), average real variabilitySBP (per 6 mmHg), and average real variabilityDBP (per 4 mmHg) were associated with new-onset CKD (odds ratios [ORs] and 95% confidence intervals, 1.15 [1.11–1.20], 1.08 [1.04–1.12], 1.13 [1.09–1.17], 1.06 [1.02–1.10], respectively; all P<0.01) after adjustment for clinical characteristics, and with mean BP from year 0 to year 3. The associations of SDBP and average real variabilityBP with CKD remained significant after additional adjustments for metabolic parameter changes during follow-up (ORs, 1.06–1.15; all P<0.01). Sensitivity analyses by sex, antihypertensive medication use, and the presence of hypertension showed similar conclusions. Among those in the middle-aged and elderly general population without diabetes mellitus, long-term BP variability during 3 years was associated with new-onset CKD risk, independently of mean or cumulative exposure to BP and metabolic profile changes during follow-up.

Confidence interval of intrinsic optimum temperature estimated using thermodynamic SSI model

The intrinsic optimum temperature for the development of ectotherms is one of the most important factors not only for their physiological processes but also for ecological and evolutional processes. The Sharpe–Schoolfield–Ikemoto (SSI) model succeeded in defining the temperature that can thermodynamically meet the condition that at a particular temperature the probability of an active enzyme reaching its maximum activity is realized. Previously, an algorithm was developed by Ikemoto (Tropical malaria does not mean hot environments. Journal of Medical Entomology, 45, 963–969) to estimate model parameters, but that program was computationally very time consuming. Now, investigators can use the SSI model more easily because a full automatic computer program was designed by Shi et al. (A modified program for estimating the parameters of the SSI model. Environmental Entomology, 40, 462–469). However, the statistical significance of the point estimate of the intrinsic optimum temperature for each ectotherm has not yet been determined. Here, we provided a new method for calculating the confidence interval of the estimated intrinsic optimum temperature by modifying the approximate bootstrap confidence intervals method. For this purpose, it was necessary to develop a new program for a faster estimation of the parameters in the SSI model, which we have also done.

Association between Combined Lifestyle Factors and Non-Restorative Sleep in Japan: A Cross-Sectional Study Based on a Japanese Health Database

Background Although lifestyle factors such as cigarette smoking, excessive drinking, obesity, low or no exercise, and unhealthy dietary habits have each been associated with inadequate sleep, little is known about their combined effect. The aim of this study was to quantify the overall impact of lifestyle-related factors on non-restorative sleep in the general Japanese population. Methods and Findings A cross-sectional study of 243,767 participants (men, 39.8%) was performed using the Specific Health Check and Guidance System in Japan. A healthy lifestyle score was calculated by adding up the number of low-risk lifestyle factors for each participant. Low risk was defined as (1) not smoking, (2) body mass index<25 kg/m2, (3) moderate or less alcohol consumption, (4) regular exercise, and (5) better eating patterns. Logistic regression analysis was used to examine the relationship between the score and the prevalence of non-restorative sleep, which was determined from questionnaire responses. Among 97,062 men (mean age, 63.9 years) and 146,705 women (mean age, 63.7 years), 18,678 (19.2%) and 38,539 (26.3%) reported non-restorative sleep, respectively. The prevalence of non-restorative sleep decreased with age for both sexes. Compared to participants with a healthy lifestyle score of 5 (most healthy), those with a score of 0 (least healthy) had a higher prevalence of non-restorative sleep (odds ratio, 1.59 [95% confidence interval, 1.29–1.97] for men and 2.88 [1.74–4.76] for women), independently of hypertension, hypercholesterolemia, diabetes, and chronic kidney disease. The main limitation of the study was the cross-sectional design, which limited causal inferences for the identified associations. Conclusions A combination of several unhealthy lifestyle factors was associated with non-restorative sleep among the general Japanese population. Further studies are needed to establish whether general lifestyle modification improves restorative sleep.

Suicide Ideation of Individuals in Online Social Networks

Suicide explains the largest number of death tolls among Japanese adolescents in their twenties and thirties. Suicide is also a major cause of death for adolescents in many other countries. Although social isolation has been implicated to influence the tendency to suicidal behavior, the impact of social isolation on suicide in the context of explicit social networks of individuals is scarcely explored. To address this question, we examined a large data set obtained from a social networking service dominant in Japan. The social network is composed of a set of friendship ties between pairs of users created by mutual endorsement. We carried out the logistic regression to identify users’ characteristics, both related and unrelated to social networks, which contribute to suicide ideation. We defined suicide ideation of a user as the membership to at least one active user-defined community related to suicide. We found that the number of communities to which a user belongs to, the intransitivity (i.e., paucity of triangles including the user), and the fraction of suicidal neighbors in the social network, contributed the most to suicide ideation in this order. Other characteristics including the age and gender contributed little to suicide ideation. We also found qualitatively the same results for depressive symptoms.

Association of High Pulse Pressure With Proteinuria in Subjects With Diabetes, Prediabetes, or Normal Glucose Tolerance in a Large Japanese General Population Sample

OBJECTIVE To examine whether there is a difference in the association between high pulse pressure and proteinuria, independent of other blood pressure (BP) indices, such as systolic or diastolic BP, among subjects with diabetes, prediabetes, or normal glucose tolerance. RESEARCH DESIGN AND METHODS Using a nationwide health checkup database of 228,778 Japanese aged ≥20 years (mean 63.2 years; 39.3% men; none had pre-existing cardiovascular disease), we examined the association between high pulse pressure, defined as the highest quintile of pulse pressure (≥63 mmHg, n = 40,511), and proteinuria (≥1+ on dipstick, n = 12,090) separately in subjects with diabetes (n = 27,913), prediabetes (n = 100,214), and normal glucose tolerance (n = 100,651). RESULTS The prevalence of proteinuria was different among subjects with diabetes, prediabetes, and normal glucose tolerance (11.3 vs. 5.0 vs. 3.9%, respectively; P < 0.001). In subjects with diabetes, but not those with prediabetes or normal glucose tolerance, high pulse pressure was associated with proteinuria independently of significant covariates, including systolic BP (odds ratio 1.15 [95% CI 1.04–1.28]) or diastolic or mean BP (all P < 0.01). In patients with diabetes, a +1 SD increase of pulse pressure (+13 mmHg) was associated with proteinuria, even after adjustment for systolic BP (1.07 [1.00–1.13]) or diastolic or mean BP (all P < 0.05). CONCLUSIONS Among the Japanese general population, there was a significant difference in the association between high pulse pressure and proteinuria among subjects with diabetes, prediabetes, and normal glucose tolerance. Only in diabetes was high pulse pressure associated with proteinuria independent of systolic, diastolic, or mean BP levels.

New-onset hypertension and risk for chronic kidney disease in the Japanese general population.

Objectives: Our aims were to assess the progression rate of normotension and prehypertension to hypertension in Japan, and the effect of the new-onset hypertension on chronic kidney disease (CKD). Methods: This was a nationwide study of 45 378 Japanese aged 40–74 years (mean age 60 years, 37% men) without hypertension or cardiovascular disease at baseline. At baseline and 3-year follow-up, blood pressure (BP) and kidney function were assessed. CKD was defined as an estimated glomerular filtration rate (eGFR) below 60 ml/min per 1.73 m2 or the presence of proteinuria (≥1+ by a dipstick). Results: At 3-year follow-up, the incidence rates of hypertension among participants with optimal BP (<120/80 mmHg, n = 18 724), normal BP (120–129/80–84 mmHg, n = 15 017) and high-normal BP (130–139/85–89 mmHg, n = 11 637) were 8, 23, and 39% in men, and 6, 20, and 37% in women, respectively. Among those without CKD at baseline (n = 42 625), 2142 participants (5%) had developed CKD during follow-up. Irrespective of the baseline BP classifications, participants with new-onset hypertension had a higher risk for proteinuria [odds ratio (95% confidence interval) 1.7 (1.3–2.3) in men and 1.6 (1.2–2.2) in women], but not for eGFR below 60 ml/min per 1.73 m2, compared with those who maintained optimal BP during follow-up. Men who remained in the high-normal BP range during follow-up showed higher risk for proteinuria [odds ratio (95% confidence interval) 1.6 (1.1–2.3)], but not for eGFR below 60 ml/min per 1.73 m2. Conclusions: This nationwide longitudinal study suggests that, over 3 years of follow-up, women and men with new-onset hypertension and men with high-normal BP were at higher risk of newly developing proteinuria.

A Microarray-Based Gene Expression Analysis to Identify Diagnostic Biomarkers for Unknown Primary Cancer

Background The biological basis for cancer of unknown primary (CUP) at the molecular level remains largely unknown, with no evidence of whether a common biological entity exists. Here, we assessed the possibility of identifying a common diagnostic biomarker for CUP using a microarray gene expression analysis. Methods Tumor mRNA samples from 60 patients with CUP were analyzed using the Affymetrix U133A Plus 2.0 GeneChip and were normalized by asinh (hyperbolic arc sine) transformation to construct a mean gene-expression profile specific to CUP. A gene-expression profile specific to non-CUP group was constructed using publicly available raw microarray datasets. The t-tests were performed to compare the CUP with non-CUP groups and the top 59 CUP specific genes with the highest fold change were selected (p-value<0.001). Results Among the 44 genes that were up-regulated in the CUP group, 6 genes for ribosomal proteins were identified. Two of these genes (RPS7 and RPL11) are known to be involved in the Mdm2–p53 pathway. We also identified several genes related to metastasis and apoptosis, suggesting a biological attribute of CUP. Conclusions The protein products of the up-regulated and down-regulated genes identified in this study may be clinically useful as unique biomarkers for CUP.