Kohzoh Yoshino

Singlet oxygen induced products of linoleates, 10- and 12-(Z,E)-hydroxyoctadecadienoic acids (HODE), can be potential biomarkers for early detection of type 2 diabetes.

Current diagnostic tests such as glycemic indicators have limitations for early detection of impaired glucose tolerance (IGT), which leads to diabetes. Oxidative stress induced by various oxidants in a random and destructive manner is considered to play an important role in the pathophysiology of a number of human disorders and diseases such as impaired glucose tolerance. We have developed an improved method for the measurement of in vivo lipid peroxidation, where the presence of 8-iso-prostaglandin F2α (8-iso-PGF2α), hydroxyoctadecadienoic acids (HODEs), hydroxyeicosatetraenoic acids (HETEs), and 7-hydroxycholesterol (7-OHCh), as well as their parent molecules, linoleic acid (LA) and cholesterol (Ch), was determined by performing LC-MS/MS (for 8-iso-PGF2α, HODE, and HETE) and GC-MS (for 7-OHCh, LA, and Ch) after reduction with triphenyl phosphine and saponification by potassium hydroxide. We then applied this method to volunteers (n = 57), including normal type (n = 43), “high-normal” (fasting plasma glucose, 100–109 mg/dL, n = 7), pre-diabetic type (IGT, n = 5), and diabetic type (n = 2) subjects who are diagnosed by performing oral glucose tolerance tests (OGTTs). Several biomarkers in plasma, such as insulin, leptin, adiponectin, interleukin-6, tumor necrosis factor-α, high sensitivity-C-reactive protein, HbA1c, and glucose levels were measured during OGTT. We found that the fasting levels of (10- and 12-(Z,E)- HODE)/LA increased significantly with increasing levels of HbA1c and glucose during OGTT and with insulin secretion and resistance index. In conclusion, 10- and 12-(Z,E)-HODE may be prominent biomarkers for the early detection of IGT and “high-normal” type without OGTT.

Effect of mood during daily life on autonomic nervous activity balance during subsequent sleep

RR-interval and eight types of mood level were recorded for 48 h from 40 normal male subjects. Sympathovagal balance was evaluated by calculating the normalized high-frequency power (HFnu) of RR-interval variability. The mean mood levels during 6 h before bedtime and the mean HFnu during 3 h after bedtime were compared. The data were normalized individually and the differences from the first night (Deltamood and DeltaHFnu) were taken. The correlation coefficient between Deltadepression and DeltaHFnu was -0.53, and that between Deltaworry and DeltaHFnu was -0.44. This implies that both daily depression and worry shift toward sympathetic dominance during subsequent sleep.

Causal coherence analysis of heart rate variability and systolic blood pressure variability under mental arithmetic task load.

Causal coherence analysis based on a closed-loop bivariate autoregressive model was applied to heart rate variability and systolic blood pressure (SBP) variability during mental arithmetic tasks to clarify how mental task load affects the linear closed loop interaction between cardiac and vascular systems. Thirteen normal male subjects performed a mental arithmetic task, button press task, and rest task while measuring their RR interval (RRI) and SBP. The mean value in the low frequency (LF) band (0.04-0.15Hz) of the squared causal coherence function from SBP to RRI during the mental arithmetic task was significantly higher than during the other two control tasks. Conversely, the LF band of the squared causal coherence function from RRI to SBP during the mental arithmetic task tended to be lower than during the rest task. These results suggest that mental arithmetic tasks enhance linear causal coupling from the vascular to cardiac system, and conversely weaken that from the cardiac to vascular system.

Multi-Biomarkers for Early Detection of Type 2 Diabetes, Including 10- and 12-(Z,E)-Hydroxyoctadecadienoic Acids, Insulin, Leptin, and Adiponectin

We have previously found that fasting plasma levels of totally assessed 10- and 12-(Z,E)-hydroxyoctadecadienoic acid (HODE) correlated well with levels of glycated hemoglobin (HbA1c) and glucose during oral glucose tolerance tests (OGTT); these levels were determined via liquid chromatography—mass spectrometry after reduction and saponification. However, 10- and 12-(Z,E)-HODE alone cannot perfectly detect early impaired glucose tolerance (IGT) and/or insulin resistance, which ultimately lead to diabetes. In this study, we randomly recruited healthy volunteers (n = 57) who had no known history of any diseases, and who were evaluated using the OGTT, the HODE biomarkers, and several additional proposed biomarkers, including retinol binding protein 4 (RBP4), adiponectin, leptin, insulin, glycoalbumin, and high sensitivity-C-reactive protein. The OGTT revealed that our volunteers included normal individuals (n = 44; Group N), “high-normal” individuals (fasting plasma glucose 100–109 mg/dL) with IGT (n = 11; Group HN+IGT), and diabetic individuals (n = 2; Group D). We then used these groups to evaluate the potential biomarkers for the early detection of type 2 diabetes. Plasma levels of RBP4 and glycoalbumin were higher in Group HN+IGT, compared to those in Group N, and fasting levels of 10- and 12-(Z,E)-HODE/linoleic acids were significantly correlated with levels of RBP4 (p = 0.003, r = 0.380) and glycoalbumin (p = 0.006, r = 0.316). Furthermore, we developed a stepwise multiple linear regression models to predict the individuals’ insulin resistance index (the Matsuda Index 3). Fasting plasma levels of 10- and 12-(Z,E)-HODE/linoleic acids, glucose, insulin, and leptin/adiponectin were selected as the explanatory variables for the models. The risks of type 2 diabetes, early IGT, and insulin resistance were perfectly predicted by comparing fasting glucose levels to the estimated Matsuda Index 3 (fasting levels of 10- and 12-(Z,E)-HODE/linoleic acids, insulin, and leptin/adiponectin).

Closed-loop analysis of cardiovascular variability in rats under restraint stress

Causal transfer function analysis was applied to the heart rate variability and blood pressure variability in normotensive male Sprague-Dawley rats those were measured before, during, and after acute restraint stress. The causal transfer gain (CTG) from systolic blood pressure (SBP) to RR interval (RRI) and CTG from RRI to SBP were estimated. The mean value of the CTG from SBP to RRI in the low-frequency (LF) band (0.27-0.74 Hz) was significantly lower during the restraint period than during the baseline period and remained significantly lower during the recovery period. The mean value of the CTG from RRI to SBP in the LF band, in contrast, was significantly higher during the restraint period than during the baseline period, and during the recovery period it tended to return relatively rapidly to the baseline level. Arterial pressure tended to increase only at the onset of the restraint stress and then to decline not only during the restraint period but also during the recovery period, finally leveling off significantly below the baseline level. These results suggest that restraint stress suppresses the baroreflex control gain not only during the restraint period but also during the recovery period and that this results in the arterial hypotension during the recovery period.

Effects of fatigue induced by long-term walking on gait and physiological rhythm

Summary form only given. We examined how long-term walking affects gait and physiological rhythm. Twelve normal subjects performed three hours above-ground walking at their own preferable pace. Subjects were divided into two groups according to whether the mean gait cycle time in the second-half increased (group A) or decreased (group B) from that in the first-half. Group A subjects showed significantly higher subjective level of fatigue than Group B subjects. Mean power frequency (MPF) of EMG recorded from tibialis anterior significantly decreased with time, indicating that it can also be used to evaluate muscle fatigue induced by weak dynamical movement such as walking. In group A subjects, moreover, mean value and coefficient of variance of gait cycle time increased significantly with time, and largest Lyapunov exponent of back-waist acceleration in vertical direction decreased significantly with time. During the rest period before the walking task, mean RR-interval in group A subjects was significantly shorter than that in group B subjects. From these results, and taking the timing of each index when it reached the significant level into account, we proposed a hypothetical model of gait and physiological responses to physical fatigue.

Basic study on the most relaxing respiration period in children to aid the development of a respiration-leading stuffed toy

Following natural disasters, accidents, and shocking incidents, some children experience post-traumatic stress disorder (PTSD). The respiration control method, which relaxes the body and mind, may efficiently prevent PTSD. Therefore, we developed a stuffed toy that leads childrens respiration using the up-and-down movement of the abdomen to help them relax. We investigated the most appropriate respiration period for childrens relaxation. Data from studies on heart rate variability (HRV) biofeedback training suggest that breathing at the respiration period at which HRV is the highest is effective for improving chronic diseases. Therefore, we measured the relationship between the respiration period and physiological indices, including HRV. The participants were 10 children aged 5-12 years. HRV was the highest at a 10-12-s respiration period in all 10 children. However, the most suitable respiration period for smooth breathing and relaxation was different from that at which HRV is the highest. Therefore, the most relaxing respiration periods for children need to be determined by indices other than HRV.

Early diagnosis of type 2 diabetes based on multiple biomarkers and non-invasive indices

We previously reported that type 2 diabetes risk, early impaired glucose tolerance and insulin resistance can be predicted by measuring the fasting levels of certain biomarkers. Here we validated these findings in randomly recruited healthy volunteers (n = 101) based on biomarker expression as well as various non-invasive indices. Weight, body mass index, waist circumference and visceral fat differed between individuals with impaired fasting glucose and/or impaired glucose tolerance, and normal subjects. Fasting plasma levels of glycated hemoglobin, leptin, pro-insulin and retinol binding protein 4 differed between impaired fasting glucose/impaired glucose tolerance and normal subjects group and between newly detected diabetes and normal subjects group. Insulin resistance was correlated with fasting levels of insulin and leptin/adiponectin (r = 0.913); of insulin, retinol binding protein 4 and leptin/adiponectin (r = 0.903); and of insulin, glycated albumin, and leptin/adiponectin (r = 0.913). Type 2 diabetes risk, early impaired glucose tolerance and insulin resistance were predicted with >98% specificity and sensitivity by comparing fasting glucose levels to the estimated Matsuda Index based on fasting levels of insulin, adiponectin and leptin with or without oxidative lineolate metabolites. Non-invasive indices are slightly correlated with glucose tolerance and insulin resistance but do not increase the accuracy of predicting type 2 diabetes risk.

High Throughput Stress Marker Assay using Polymer Microchip Electrophoresis with Laser induced fluorescence Detection

High throughput microchip assay for catecholamines with laser induced fluorescence detection, which has several advantages for human-fluids monitoring. We optimized electrophoretic separation condition for disposable polymer chip and applied the human saliva before/after the tension-stress model. We demonstrated successfully the stress marker assay is useful using disposable microchip assay.