Five Amino Acid Residues Responsible for the High Stability of Hydrogenobacter thermophilus Cytochrome c552

Five amino acid residues responsible for extreme stability have been identified in cytochrome c552 (HT c552) from a thermophilic bacterium, Hydrogenobacter thermophilus. The five residues, which are spatially distributed in three regions of HT c552, were replaced with the corresponding residues in the homologous but less stable cytochrome c551 (PA c551) from Pseudomonas aeruginosa. The quintuple HT c552 variant (A7F/M13V/Y34F/Y43E/I78V) showed the same stability against guanidine hydrochloride denaturation as that of PA c551, suggesting that the five residues in HT c552 necessarily and sufficiently contribute to the overall stability. In the three HT c552 variants carrying mutations in each of the three regions, the Y34F/Y43E mutations resulted in the greatest destabilization, by –13.3 kJ mol–1, followed by A7F/M13V (–3.3 kJ mol–1) and then I78V (–1.5 kJ mol–1). The order of destabilization in HT c552 was the same as that of stabilization in PA c551 with reverse mutations such as F34Y/E43Y, F7A/V13M, and V78I (13.4, 10.3, and 0.3 kJ mol–1, respectively). The results of guanidine hydrochloride denaturation were consistent with those of thermal denaturation for the same variants. The present study established a method for reciprocal mutation analysis. The effects of side-chain contacts were experimentally evaluated by swapping the residues between the two homologous proteins that differ in stability. A comparative study of the two proteins was a useful tool for assessing the amino acid contribution to the overall stability.This work was supported in part by grants from Hiroshima University, the Noda Institute for Scientific Research, and the Japanese Ministry of Education, Science and Culture (grants-in-aid for Scientific Research on Priority Areas)

KP solitons in shallow water

The main purpose of the paper is to provide a survey of our recent studies on soliton solutions of the Kadomtsev-Petviashvili (KP) equation. The classification is based on the far-field patterns of the solutions which consist of a finite number of line-solitons. Each soliton solution is then defined by a point of the totally non-negative Grassmann variety which can be parametrized by a unique derangement of the symmetric group of permutations. Our study also includes certain numerical stability problems of those soliton solutions. Numerical simulations of the initial value problems indicate that certain class of initial waves asymptotically approach to these exact solutions of the KP equation. We then discuss an application of our theory to the Mach reflection problem in shallow water. This problem describes the resonant interaction of solitary waves appearing in the reflection of an obliquely incident wave onto a vertical wall, and it predicts an extra-ordinary four-fold amplification of the wave at the wall. There are several numerical studies confirming the prediction, but all indicate disagreements with the KP theory. Contrary to those previous numerical studies, we find that the KP theory actually provides an excellent model to describe the Mach reflection phenomena when the higher order corrections are included to the quasi-two dimensional approximation. We also present laboratory experiments of the Mach reflection recently carried out by Yeh and his colleagues, and show how precisely the KP theory predicts this wave behavior.Comment: 50 pages, 25 figure

Prevalence of the metabolic syndrome in elderly and middle-aged Japanese

AbstractBackground/PurposeDiagnosis and management of the metabolic syndrome (MetS) are beneficial for successful aging. In spite of several criteria for MetS, there is little information on cardiometabolic risk clustering in elderly Japanese. The purpose of this study was, therefore, to determine the relationship between age-associated changes in obesity and metabolic components in the Japanese.MethodsWe analyzed data from the nationwide survey conducted in 2000. Using Adult Treatment Panel III (ATP III) and Japanese diagnostic criteria for MetS, we analyzed 2366 people aged from 40 to 79 years (men, 1425 and women, 941) from the total participants.ResultsThe prevalence of MetS was almost three fold higher by modified ATP III, International Diabetes Federation, and Japanese criteria, in elderly women than in middle-aged women, whereas no difference was found between middle-aged and elderly men by the three criteria. A marked increase in the prevalence of MetS was found by modified ATP III and International Diabetes Federation criteria compared with that by the Japanese criteria in women. Among the risk factors, the prevalence of central obesity and dyslipidemia increased only in women and that of high fasting glucose and high blood pressure increased in both genders with aging. Among the MetS subjects who fulfilled the modified ATP III criteria, more clustering of risk was observed in elderly than in middle-aged subjects, especially in women. Blood pressure increased and triglyceride decreased in both genders, and non-high-density-lipoprotein cholesterol decreased in elderly men. The prevalence of dyslipidemia decreased in elderly men.ConclusionAging is an important factor that affects the metabolic abnormality, and aging of the population would lead to increase in the prevalence of MetS. Therefore, the development of better approaches to the prevention and management of MetS is necessary for successful aging in our society

Single ingestion of soy β-conglycinin induces increased postprandial circulating FGF21 levels exerting beneficial health effects

Soy protein β-conglycinin has serum lipid-lowering and anti-obesity effects. We showed that single ingestion of β-conglycinin after fasting alters gene expression in mouse liver. A sharp increase in fibroblast growth factor 21 (FGF21) gene expression, which is depressed by normal feeding, resulted in increased postprandial circulating FGF21 levels along with a significant decrease in adipose tissue weights. Most increases in gene expressions, including FGF21, were targets for the activating transcription factor 4 (ATF4), but not for peroxisome proliferator-activated receptor α. Overexpression of a dominant-negative form of ATF4 significantly reduced β-conglycinin-induced increases in hepatic FGF21 gene expression. In FGF21-deficient mice, β-conglycinin effects were partially abolished. Methionine supplementation to the diet or primary hepatocyte culture medium demonstrated its importance for activating liver or hepatocyte ATF4-FGF21 signaling. Thus, dietary β-conglycinin intake can impact hepatic and systemic metabolism by increasing the postprandial circulating FGF21 levels.UTokyo Research掲載「大豆のタンパク質1回摂取で代謝を改善する因子が急増」 URI: http://www.u-tokyo.ac.jp/ja/utokyo-research/research-news/single-ingestion-of-soy-protein-improves-metabolism.htmlUTokyo Research "Single ingestion of soy protein improves metabolism" URI: http://www.u-tokyo.ac.jp/en/utokyo-research/research-news/single-ingestion-of-soy-protein-improves-metabolism.htm

Sustained reduction of serum cholesterol in low-dose 6-year simvastatin treatment with minimum side effects in 51,321 Japanese hypercholesterolemic patients - Implication of the J-LIT study, a large scale nationwide cohort study

金沢大学大学院医学系研究科　The Japan Lipid Intervention Trial (J-LIT) study, a nationwide cohort study utilizing the clinical practice of general physicians, was designed to clarify the relationship between the incidence of coronary heart disease and serum lipid concentrations during simvastatin therapy, as well as the safety of the therapy, in a large number of Japanese hypercholesterolemic patients. All the enrolled patients were treated with simvastatin. The current study analyzed the lipid lowering effect and safety of the low-dose simvastatin therapy used in the J-LIT study. Open-labeled simvastatin was given to 51,321 patients at an initial dose of mostly 5 mg/day. After 6 months of the treatment, the average serum total cholesterol (TC) and low density lipoprotein-cholesterol concentrations in all the patients followed up were reduced by 18.3% and 26.0%, respectively, and that of high density lipoprotein-cholesterol increased 2.3% on average. These concentrations were well maintained throughout the 6-year treatment period. A minority of patients (1.4%) unexpectedly had a remarkable reduction in TC concentration by more than 40%. Hyper-responders, even to low-dose statin, were found for the first time in this large-scale and long-term investigation. Overall adverse drug reactions occurred in 3.3% of subjects during the 6-year treatment, the major events being hepatic and musculoskeletal disorders, of which the incidence was less than 1%. Low-dose simvastatin therapy of 5 mg/day effectively controlled the serum TC concentration by reducing it by approximately 20% on average in hypercholesterolemic Japanese patients, a reduction that corresponds to the effect of simvastatin 20 mg/day in Western studies. In addition, the low incidence of drug-related adverse events in this study may. be also related to the low dosage of simvastatin

Large-scale cohort study on the relationship between serum lipid concentrations and risk of cerebrovascular disease under low-dose simvastatin in Japanese patients with hypercholesterolemia: Sub-analysis of the Japan Lipid Intervention Trial (J-LIT)

金沢大学大学院医学系研究科　Background: The Japan Lipid Intervention Trial was a nationwide cohort study of 52,421 hypercholesterolemic patients treated with open-labeled simvastatin for 6 years under standard clinical practices. Cerebrovascular disease (CVD) is one of the leading causes of death in Japan, but the effect of hypercholesterolemia on CVD has not been well established in Japanese patients. This study aimed to determine the relationship between the risk of CVD and serum lipid concentrations during treatment in Japan. Methods and Results: Patients were treated with 5-10 mg/day of simvastatin and all, including those who discontinued simvastatin for any reason, had their lipid concentrations and incidence of CVD monitored for 6 years. Data of 41,088 patients were analyzed in this study, excluding those who had a history of coronary heart disease or CVD. The risk of cerebral infarction was higher in patients whose mean total cholesterol concentrations during treatment were ≥240 mg/dl, low-density lipoprotein cholesterol concentrations ≥160 mg/dl, triglycerides ≥150 mg/dl and high-density lipoprotein cholesterol concentrations <40 mg/dl. There was no obvious correlation between cerebral hemorrhage and serum lipid concentrations. Conclusion: Improvement of serum lipid concentrations is important for reducing the incidence of cerebral infarction

A comparative study of the sarcopenia screening in older patients with interstitial lung disease

Background: The Asian Working Group for Sarcopenia 2019 (AWGS 2019) is the gold standard diagnostic criteria for sarcopenia in Asian populations. The calf circumference (CalF), the strength, assistance in walking, rising from a chair, climbing stairs, and falls (SARC-F) and the SARC-CalF questionnaires for sarcopenia screening have been used by AWGS 2019. The aim of this study was to assess accuracy of these three sarcopenia screening tools in patients with interstitial lung disease.Methods: In this cross-sectional study, stable patients with interstitial lung disease were enrolled. The SARC-F, SARC-CalF, and CalF, used in patients with interstitial lung disease, were compared to the diagnostic criteria proposed by AWGS 2019. The accuracy of screening tools was compared using sensitivity and specificity. Moreover, areas under the receiver operating characteristic curves (AUC) were computed.Results: Seventy eight patients were analyzed, and sarcopenia was identified in 25 (32.1%) patients with interstitial lung disease by the AWGS 2019 criteria. The sensitivity of the CalF was highest (96%) of the three screening tools, while the specificity was 60%. The sensitivity of SARC-F and SARC-CalF were 24% and 68%, while the specificity were 92% and 66%, respectively. The AUCs of CalF, SARC-F, and SARC-CalF in all patients were 0.78, 0.58, and 0.67, respectively.Conclusions: The CalF is most suitable for screening sarcopenia in patients with interstitial lung disease, while SARC-F and SARC-CalF are not

Effects of daily aspirin on cancer incidence and mortality in the elderly Japanese

BackgroundLong‐term follow‐up of studies to investigate preventive effects of aspirin on arterial thrombosis indicate that aspirin reduces the incidence and mortality of some cancers in Western populations.ObjectivesTo explore the effects of aspirin on cancer incidence and mortality in the elderly Japanese.Patients/MethodsPatients aged 60 to 85 years, presenting with hypertension, dyslipidemia, or diabetes mellitus (n = 14 601, 7297 in the aspirin group and 7304 in the no‐aspirin group) participated the Japanese Primary Prevention Project (JPPP), a multicenter, open‐label, randomized, parallel‐group trial. A subanalysis of JPPP was performed to analyze the incidence of newly diagnosed cancer and death related to cancer.ResultsThe cumulative incidence of newly diagnosed cancer was 5.60% (4.65‐6.64%) in the aspirin group and 4.14% (3.67‐4.66%) in the no‐aspirin group. The hazard ratio for newly diagnosed cancer was 1.24 (1.06‐1.46), and the cancer incidence was significantly higher in the aspirin group. The cumulative cancer mortality was 1.96% (1.65‐2.31%) in the aspirin group and 1.87% (1.56‐2.22%) in the no‐aspirin group, with no statistically significant difference. The Fine and Gray model suggested that the difference in the incidence of newly diagnosed cancer between the two groups decreased year by year.ConclusionsLow‐dose aspirin use did not reduce the cancer incidence or cancer mortality during a 5‐year‐average study period in the elderly Japanese. The cancer incidence in the aspirin group might decrease, however, to less than that in the no‐aspirin group after the study period. Aspirin use might have led to earlier cancer diagnosis in our study