Association of scan frequency with CGM-derived metrics and influential factors in adults with type 1 diabetes mellitus

Introduction

This study aimed to investigate the association between scan frequency and intermittently scanned continuous glucose monitoring (isCGM) metrics and to clarify the factors affecting scan frequency in adults with type 1 diabetes mellitus (T1D).

Methods

We enrolled adults with T1D who used FreeStyle® Libre. Scan and self-monitoring of blood glucose (SMBG) frequency and CGM metrics from the past 90-day glucose data were collected. The receiver operating characteristic curve was plotted to obtain the optimal cutoff values of scan frequency for the target values of time in range (TIR), time above range (TAR), and time below range (TBR).

Results

The study was conducted on 211 adults with T1D (mean age, 50.9 ± 15.2 years; male, 40.8%; diabetes duration, 16.4 ± 11.9 years; duration of CGM use, 2.1 ± 1.0 years; and mean HbA1c, 7.6 ± 0.9%). The average scan frequency was 10.5 ± 3.3 scan/day. Scan frequency was positively correlated with TIR and negatively correlated with TAR, although it was not significantly correlated with TBR. Scan frequency was positively correlated with the hypoglycemia fear survey-behavior score, while it was negatively correlated with some glycemic variability metrics. Adult patients with T1D and good exercise habits had a higher scan frequency than those without exercise habits. The AUC for > 70% of the TIR was 0.653, with an optimal cutoff of 11 scan/day.

Conclusions

In real-world conditions, frequent scans were linked to improved CGM metrics, including increased TIR, reduced TAR, and some glycemic variability metrics. Exercise habits and hypoglycemia fear-related behavior might affect scan frequency. Our findings could help healthcare professionals use isCGM to support adults with T1D.Clinical Trial Registry No. UMIN000039376.

Optimization of nutritional strategies using a mechanistic computational model in prediabetes: Application to the J-DOIT1 study data

Lifestyle interventions have been shown to prevent or delay the onset of diabetes; however, inter-individual variability in responses to such interventions makes lifestyle recommendations challenging. We analyzed the Japan Diabetes Outcome Intervention Trial-1 (J-DOIT1) study data using a previously published mechanistic simulation model of type 2 diabetes onset and progression to understand the causes of inter-individual variability and to optimize dietary intervention strategies at an individual level. J-DOIT1, a large-scale lifestyle intervention study, involved 2607 subjects with a 4.2-year median follow-up period. We selected 112 individuals from the J-DOIT1 study and calibrated the mechanistic model to each participant's body weight and HbA1c time courses. We evaluated the relationship of physiological (e.g., insulin sensitivity) and lifestyle (e.g., dietary intake) parameters with variability in outcome. Finally, we used simulation analyses to predict individually optimized diets for weight reduction. The model predicted individual body weight and HbA1c time courses with a mean (±SD) prediction error of 1.0 kg (±1.2) and 0.14% (±0.18), respectively. Individuals with the most and least improved biomarkers showed no significant differences in model-estimated energy balance. A wide range of weight changes was observed for similar model-estimated caloric changes, indicating that caloric balance alone may not be a good predictor of body weight. The model suggests that a set of optimal diets exists to achieve a defined weight reduction, and this set of diets is unique to each individual. Our diabetes model can simulate changes in body weight and glycemic control as a result of lifestyle interventions. Moreover, this model could help dieticians and physicians to optimize personalized nutritional strategies according to their patients' goals.

To Use or Not to Use a Self-monitoring of Blood Glucose System? Real-world Flash Glucose Monitoring Patterns Using a Cluster Analysis of the FGM-Japan Study

Objective This study investigated self-monitoring of blood glucose (SMBG) adherence and flash glucose monitoring patterns using a cluster analysis in Japanese type 1 diabetes (T1D) patients with intermittently scanned continuous glucose monitoring (isCGM). Methods We measured SMBG adherence and performed a data-driven cluster analysis using a hierarchical clustering in T1D patients from Japan using the FreeStyle Libre system. Clusters were based on three variables (testing glucose frequency and referred Libre data for hyperglycemia or hypoglycemia). Patients We enrolled 209 participants. Inclusion criteria were patients with T1D, duration of isCGM use ≥3 months, age ≥20 years old, and regular attendance at the collaborating center. Results The rate of good adherence to SMBG recommended by a doctor was 85.0%. We identified three clusters: cluster 1 (low SMBG test frequency but high reference to Libre data, 17.7%), cluster 2 (high SMBG test frequency but low reference to Libre data, 34.0%), and cluster 3 (high SMBG test frequency and high reference to Libra data, 48.3%). Compared with other clusters, individuals in cluster 1 were younger, those in cluster 2 had a shorter Libre duration, and individuals in cluster 3 had lower time-in-range, higher severe diabetic distress, and high intake of snacks and sweetened beverages. There were no marked differences in the incidence of diabetic complications and rate of wearing the Libre sensor among the clusters. Conclusion We stratified the patients into three subgroups with varied clinical characteristics and CGM metrics. This new substratification might help tailor diabetes management of patients with T1D using isCGM.

Association of a pro-inflammatory diet and gestational diabetes mellitus with maternal anemia and hemoglobin levels during pregnancy: a prospective observational case-control study

Anemia is prevalent in pregnant women, and the causes include inadequate diet, increased demand for iron, and inflammation. We hypothesized that gestational diabetes mellitus (GDM) and hepcidin-related gene polymorphisms may contribute to maternal anemia and that an anti-inflammatory diet can alleviate this negative effect. The aim of this study was to investigate the association of an inflammatory diet, GDM, and single nucleotide polymorphisms (SNPs) in hepcidin-related genes, which are key regulators of iron, with maternal anemia. This was a secondary data analysis of a prospective prenatal diet and pregnancy outcome study in Japan. The Energy-Adjusted Dietary Inflammatory Index was calculated using a brief self-administered diet history questionnaire. We analyzed 121 SNPs in 4 genes: TMPRS6 (43 SNPs), TF (39 SNPs), HFE (15 SNPs), and MTHFR (24 SNPs). Multivariate regression analysis was conducted to determine the association between the first variable and maternal anemia. The prevalence of anemia in first, second, and third trimesters were 5.4%, 34.9%, and 45.8%, respectively. The pregnant women with GDM had a significantly higher incidence of moderate anemia than those without GDM (40.0% vs. 11.4%, P = .029). In multivariate regression analysis, Energy-adjusted Dietary Inflammatory Index (β = -0.057, P = .011) and GDM (β = -0.657, P = .037) were significantly associated with hemoglobin levels during the third trimester. Using Stata's qtlsnp command, TMPRSS6 rs2235321 was found to be associated with hemoglobin levels during the third trimester. These results indicate that inflammatory diets, GDM, and TMPRSS6 rs2235321 polymorphism are associated with maternal anemia. This result suggests that a pro-inflammatory diet and GDM are associated with maternal anemia.

Protective and risk factors of impaired awareness of hypoglycemia in patients with type 1 diabetes: a cross-sectional analysis of baseline data from the PR-IAH study

BACKGROUND

Hypoglycemia in type 1 diabetes (T1D) is associated with mortality and morbidity, especially when awareness of hypoglycemia is impaired. This study aimed to investigate the protective and risk factors for impaired awareness of hypoglycemia (IAH) in adults with T1D.

METHODS

This cross-sectional study enrolled 288 adults with T1D (mean age, 50.4 ± 14.6 years; male, 36.5%; diabetes duration, 17.6 ± 11.2 years; mean HbA1c level, 7.7 ± 0.9%), who were divided into IAH and non-IAH (control) groups. A survey was conducted to assess hypoglycemia awareness using the Clarke questionnaire. Diabetes histories, complications, fear of hypoglycemia, diabetes distress, hypoglycemia problem-solving abilities, and treatment data were collected.

RESULTS

The prevalence of IAH was 19.1%. Diabetic peripheral neuropathy was associated with an increased risk of IAH (odds ratio [OR] 2.63; 95% confidence interval [CI] 1.13-5.91; P = 0.014), while treatment with continuous subcutaneous insulin infusion and hypoglycemia problem-solving perception scores were associated with a decreased risk of IAH (OR, 0.48; 95% CI, 0.22-0.96; P = 0.030; and OR, 0.54; 95% CI, 0.37-0.78; P = 0.001, respectively). There was no difference in continuous glucose monitoring use between the groups.

CONCLUSION

We identified protective factors in addition to risk factors for IAH in adults with T1D. This information may help manage problematic hypoglycemia.

TRIAL REGISTRATION

University hospital Medical Information Network (UMIN) Center: UMIN000039475). Approval date 13 February 2020.

The Effect of a mHealth App (KENPO-app) for Specific Health Guidance on Weight Changes in Adults With Obesity and Hypertension: Pilot Randomized Controlled Trial

BACKGROUND

Commercial smartphone apps that promote self-monitoring of weight loss are widely available. The development of disease-specific apps has begun, but there is no app for specific health guidance (SHG) to prevent metabolic syndrome, type 2 diabetes, and cardiovascular diseases in middle-aged adults in Japan.

OBJECTIVE

This study aimed to determine the efficacy of an SHG mobile health app in facilitating weight loss in Japanese adults with obesity and hypertension.

METHODS

In a 12-week, statistician-blinded, randomized parallel controlled trial, 78 overweight and obese men aged 40-69 years were assigned in a 1:1 ratio to either the usual support plus KENPO-app group (intervention group) or the active control group. KENPO-app (release April 10, 2019; OMRON Healthcare Co., Ltd.) was developed by the study team and focus groups and uses behavior change techniques (ie, self-monitoring and goal-setting theory). This app was developed for SHG based on the four specific health checkups and guidance system in Japan: (1) focusing primarily on achieving the target (weight loss of ≥2 kg); (2) assessing healthy eating, exercise habits, smoking habits, relaxation, and self-weighing; (3) providing information on the results of specific health checkups; and (4) starting an intervention period of 6 months with the interim assessment at 3 months. The initial assessment explored the following: personality traits (4 types), health checkup data concerns (10 items), symptom concerns (10 items), and the aim of the intervention (weight loss, improving fitness, symptoms, laboratory data). Chatbot-supported health information on health and health behavior was selected from 392 quizzes based on app data and was provided to participants. The KENPO-app had chatbot-supported feedback and information provision combined with a self-monitoring tool (weight, steps, and blood pressure). Data on active exercise, healthy eating, and healthy lifestyle habits were obtained using a web-based self-administered questionnaire at baseline and 12 weeks.

RESULTS

The trial's retention rate was 95% (74/78). The adherence to daily self-weighing, wearing the pedometer, and blood pressure monitoring in the KENPO-app group was significantly higher than those in the active control group. Compared with the active control group, the median body weight and BMI of the intervention group significantly decreased at 3 months (-0.4, IQR -2.0 to 0.6 kg vs -1.1, IQR -2.7 to -0.5 kg; P=.03; -0.1, IQR -0.6 to 0.3 kg vs -0.4, IQR -0.8 to -0.2 kg; P=.02, respectively). The intervention increased the percentage of participants who self-reported taking ≥8000 steps, eating vegetables before rice, eating slowly, and relaxing. Personality traits were associated with the degree of weight loss in the intervention group.

CONCLUSIONS

The SHG-specific KENPO-app was feasible and induced modest but significant weight loss in adults with obesity.

TRIAL REGISTRATION

University Hospital Medical Information Network Center UMIN000046263; https://tinyurl.com/bderys3b.

Factors associated with hemoglobin glycation index in adults with type 1 diabetes mellitus: The FGM-Japan study

AIMS/INTRODUCTION

The discrepancy between HbA1c and glucose exposure may have significant clinical implications; however, the association between the hemoglobin glycation index (HGI) and clinical parameters in type 1 diabetes remains controversial. This study aimed to find the factors associated with HGI (laboratory HbA1c - predicted HbA1c derived from the continuous glucose monitoring [CGM]).

MATERIALS AND METHODS

We conducted a cross-sectional study of adults with type 1 diabetes (n = 211, age 50.9 ± 15.2 years old, female sex = 59.2%, duration of CGM use = 2.1 ± 1.0 years). All subjects wore the CGM for 90 days before HbA1c measurement. Data derived from the FreeStyle Libre sensor were used to calculate the glucose management indicator (GMI) and glycemic variability (GV) parameters. HGI was defined as the difference between the GMI and the laboratory HbA1c levels. The participants were divided into three groups according to the HGI tertile (low, moderate, and high). Multivariate regression analyses were performed.

RESULTS

The female sex ratio, HbA1c, and % coefficient of variation (%CV) significantly increased over the HGI tertile, while eGFR and Hb decreased over the HGI tertile. In multivariate analysis, the factors associated with HGI were %CV and eGFR, after adjusting for HbA1c level and sex (R²  = 0.44).

CONCLUSIONS

This study demonstrated that HGI is associated with female sex, eGFR, and some glycemic variability indices, independently of HbA1c. Minimizing glycemic fluctuations might reduce HGI. This information provides diabetic health professionals and patients with personalized diabetes management for adults with type 1 diabetes.

Association of Impaired Awareness of Hypoglycemia with Driving Safety and Hypoglycemia Problem-solving Abilities among Patients with Type 1 Diabetes in Japan: The PR-IAH Study

Objective Patients with type 1 diabetes (T1D) and impaired awareness of hypoglycemia (IAH) are at an elevated risk of experiencing automobile accidents. We therefore investigated the association of IAH with driving safety and hypoglycemia problem-solving abilities in adults with T1D. Methods This cross-sectional survey used Gold's method in adult patients with T1D at the National Hospital Organization (NHO) Hospital from February 14, 2020, to October 31, 2021. The participants were divided into control and IAH groups. The data included information on demographics, worries and distress regarding hypoglycemia, hypoglycemia problem-solving abilities, and adverse driving events. Patients We enrolled 233 participants (mean age: 48.5±12.8 years old, mean hemoglobin A1c level: 7.6%±0.9%) from NHO collaborating centers in Japan. Results Among a total of 233 participants (mean age: 48.5±12.8 years old, mean hemoglobin A1c level: 7.6%±0.9%), the prevalence rate of IAH was 11.6% [95% confidence interval (CI): 7.8-16.4%]. IAH was significantly associated with near-miss car accidents (odds ratio: 5.41; 95% CI:1.64-17.80). Diabetic peripheral neuropathy was associated with an increased risk of IAH, while treatment with continuous subcutaneous insulin infusion was not associated with a decreased risk of IAH. The average hypoglycemia problem-solving perception, detection control, and seeking preventive strategies scores in the IAH group were significantly reduced compared with those in the control group. Conclusion IAH was associated with an increased risk of near-miss car accidents among adults with T1D. Furthermore, good hypoglycemia problem-solving abilities were associated with a decreased risk of IAH.

Prevention of hypoglycemia by intermittent-scanning continuous glucose monitoring device combined with structured education in patients with type 1 diabetes mellitus: A randomized, crossover trial

AIMS

We conducted a randomized, crossover trial to compare intermittent-scanning continuous glucose monitoring (isCGM) device with structured education (Intervention) to self-monitoring of blood glucose (SMBG) (Control) in the reduction of time below range.

METHODS

This crossover trial involved 104 adults with type 1 diabetes mellitus (T1DM) using multiple daily injections. Participants were randomly allocated to either sequence Intervention/Control or sequence Control/Intervention. During the Intervention period which lasted 84 days, participants used the first-generation FreeStyle Libre (Abbott Diabetes Care, Alameda, CA, USA) and received structured education on how to prevent hypoglycemia based on the trend arrow and by frequent sensor scanning (≥10 times a day). Confirmatory SMBG was conducted before dosing insulin. The Control period lasted 84 days. The primary endpoint was the decrease in the time below range (TBR; <70 mg/dL).

RESULTS

The time below range was significantly reduced in the Intervention arm compared to the Control arm (2.42 ± 1.68 h/day [10.1 %±7.0 %] vs 3.10 ± 2.28 h/day [12.9 %±9.5 %], P = 0.012). The ratio of high-risk participants with low blood glucose index >5 was significantly reduced (8.6 % vs 23.7 %, P < 0.001).

CONCLUSIONS

The use of isCGM combined with structured education significantly reduced the time below range in patients with T1DM.

Predictive Factors of the Adherence to Real-Time Continuous Glucose Monitoring Sensors: A Prospective Observational Study (PARCS STUDY)

BACKGROUND

Information about factors related to better adherence to continuous glucose monitoring (CGM) sensor adherence is quite limited.

MATERIALS AND METHODS

Forty-six participants with type 1 diabetes using continuous subcutaneous insulin infusion (CSII) without CGM were recruited. The participants' characteristics and diabetes-related quality of life (QOL) were evaluated at baseline and one year after starting to use CGM. Participants wearing the sensor for ≥60% of the time were considered as adherent.

RESULTS

The mean age of the 46 participants was 44.1 ± 15.0 years old and the mean glycohemoglobin (HbA1c) was 7.7 ± 1.0%; 60.9% of the participants were classified as adherent. The duration of using CSII was longer in the adherent group, and the degree of diabetic retinopathy was significantly different. There were no significant differences in age, frequency of self-monitoring of blood glucose, or Hypoglycemia Fear Survey (HFS-B for behavior, HFS-W for worry) score at baseline between the adherent and nonadherent groups. The Problem Areas in Diabetes (PAID) score at baseline was significantly higher and the total CSII-QOL score at baseline was significantly lower in the adherent group. The usage of dual-wave bolus was significantly increased in the adherent group (34.6%-61.5%, P = .016), but not in the nonadherent group (33.3%-33.3%, P > .999). The HbA1c level showed a significant improvement in the adherent group (7.8%-7.3%, P < .001), but not in the nonadherent group (7.5%-7.2%, P = .102).

CONCLUSIONS

Higher adherence to CGM sensors may be associated with a heavier emotional burden of diabetes and a worse QOL in relation to CSII at baseline.

Protocol for a Randomized, Crossover Trial to Decrease Time in Hypoglycemia by Combined Intervention of the Usage of Intermittent-Scanning Continuous Glucose Monitoring Device and the Structured Education Regarding its Usage: Effect of Intermittent-Scanning Continuous Glucose Monitoring to Glycemic Control Including Hypoglycemia and Quality of Life of Patients with Type 1 Diabetes Mellitus Study (ISCHIA Study)

OBJECTIVE

Intermittent-scanning continuous glucose monitoring (isCGM) is widely used in type 1 diabetes (T1D) patients; however, the education required to prevent hypoglycemia by using isCGM is not established. This study examines the combined effect of isCGM device usage and the education to reduce the time in hypoglycemia in comparison to conventional self-monitoring of blood glucose (SMBG).

METHODS

The Effect of Intermittent-Scanning Continuous Glucose Monitoring to Glycemic Control Including Hypoglycemia and Quality of Life of Patients with Type 1 Diabetes Mellitus Study (ISCHIA Study), a randomized, crossover trial, enrolls 104 T1D patients (age, 20-74 years) with T1D. Participants are randomized to use isCGM combined with structured education (Intervention period) or SMBG (Control period) for 84 days, followed by the other for a further 84 days. During the Intervention period, participants have access to the sensor glucose levels and trend arrow of the device. During the Control period, participants conduct SMBG at least three times a day, and retrospective CGM is used to record the blinded sensor glucose levels. The primary endpoint is the decrease of time in hypoglycemia ( < 70 mg/dL) per day (hour/day) during the Intervention period compared with the Control period. The secondary endpoints include other indices of glycemic control, glycoalbumin, accuracy of isCGM, diabetes-related quality of life (QOL), adherence, and cost-effectiveness. The study protocol has received Certified Review Board (CRB) approval from National Hospital Organization Osaka National Hospital (N2018002, Feb 14, 2019). This study is carried out in accordance with the Declaration of Helsinki and the Clinical Trials Act. The findings will be published in peer-reviewed journals.

CONCLUSION

The ISCHIA study will contribute to the standardization of patient education regarding the prevention of hypoglycemia by using isCGM.

Impact of telephone support programme using telemonitoring on stage of change towards healthy eating and active exercise in people with prediabetes

INTRODUCTION

This study evaluated the impact of a telephone support programme with telemonitoring on changes in healthy eating and active exercise in adults with prediabetes using the stage of change framework.

METHODS

We performed a post hoc analysis using data from the Japan Diabetes Outcome Trial-1. A total of 2607 participants aged 20-65 years with impaired fasting glucose were recruited from the workplace/community in Japan and randomized to a one year telephone support programme intervention arm (n = 1240) or self-directed control arm (n = 1367). Participants in both arms received monthly data feedback from a weight scale and pedometer. The main outcome measure was the stages of change toward healthy eating and active exercise. The secondary outcome was fasting plasma glucose (FPG).

RESULTS

After the one year intervention, the adjusted odds ratio of progressing to the action/maintenance stage in the intervention vs. control arm for healthy eating was 1.31 (95% confidence interval (CI) 1.21-1.43; p < 0.001), but that for active exercise was 1.07 (95% CI 0.99-1.15; p = 0.062). The intervention decreased FPG levels in participants in the contemplation stage, but not in the precontemplation, preparation and action/maintenance stages.

DISCUSSION

These findings suggest that the telephone support programme by healthcare providers advanced the stage of changes toward healthy eating in people with prediabetes. In particular, it decreased FPG levels in the contemplation stage.

Association Between Psychological Distress and Stress-Related Symptoms and Increased Risk of Type 2 Diabetes in Male Individuals: An Observational Study

Background

This study evaluated the association between psychological distress and development of type 2 diabetes (T2D) among male individuals in the workplace.

Methods

This observational cohort study enrolled 6,326 male participants aged 18 - 65 years (mean age 47.4 ± 9.5 years, body mass index 23.4 ± 3.4 kg/m², hemoglobin A1c 5.5±0.3%), who received annual health checkups from April 2016 to March 2017. Those who had a hemoglobin A1c level ≥ 6.5%, previous history of diabetes, or used diabetes medication were excluded from the analysis. Psychological distress was measured using the Brief Job Stress Questionnaire. Multivariate Cox proportional hazard regression models were used to estimate the development of T2D in relation to psychological distress and stress-related symptoms. The calculated hazard ratio (aHR) was adjusted for age, body mass index, and hemoglobin A1c level.

Results

During a mean follow-up period of 1.9 years, the incidence rate of new-onset T2D was 2.0%. Baseline psychological parameters did not differ between participants with or without new-onset T2D. Depression was associated with an increased risk of T2D (aHR = 1.54, 95% confidence interval (CI): 1.07 - 2.22), whereas vigor, irritation, fatigue, and anxiety were not. Moreover, inability to handle work (aHR = 2.18, 95% CI: 1.14 - 4.19), sadness (aHR = 1.93, 95% CI: 1.14 - 3.26), headache (aHR = 1.98, 95% CI: 1.18 - 3.34), shoulder stiffness (aHR = 1.56, 95% CI: 1.10 - 2.23), and constipation/diarrhea (aHR = 1.71, 95% CI: 1.04 - 2.80) were associated with T2D incidence.

Conclusions

Depression and stress-related symptoms were associated with an increased risk of T2D. Industrial physicians and health care providers should evaluate these factors during health checkups to lower the T2D incidence in this population

Self-weighing frequency and the incidence of type 2 diabetes: post hoc analysis of a cluster-randomized controlled trial

Objectives

Frequent self-weighing is associated with weight loss and maintenance, but the relationship between frequent self-weighing and the incidence of type 2 diabetes (T2D) remains unclear. The study aim was to examine the association between self-weighing frequency and the incidence of T2D in people with impaired fasting glucose (IFG).

Results

We tested the hypothesis that self-weighing frequency and the incidence of T2D are associated in 2607 people with IFG (1240 in the intervention arm; 1367 in the self-directed control arm). Both arms received a weighing scale with storage function. Healthcare providers offered a one-year goal-focused lifestyle intervention via phone. Participants were divided into 4 categories based on self-weighing frequency (No data sent [reference group], low: < 2 times/week, middle: 3–4 times/week, and high: 5–7 times/week). The adjusted hazard ratio (AHR) and 95% confidence interval (CI) were calculated. In the intervention arm, middle- and high-frequency self-weighing were associated with a decreased incidence of T2D relative to the reference group (AHR = 0.56, 95% CI [0.32, 0.98] and AHR = 0.43, 95% CI [0.25, 0.74], respectively). In the control arm, high-frequency self-weighing was also associated with a decreased incidence of T2D relative to the reference group (AHR = 0.54, 95% CI [0.35, 0.83]).

Trial registration This trial has been registered with the University Hospital Medical Information Network (UMIN000000662).

Effects of obesity, metabolic syndrome, and non-alcoholic or alcoholic elevated liver enzymes on incidence of diabetes following lifestyle intervention: A subanalysis of the J-DOIT1

Objectives

Using annual health check‐up data, the aim of this study was to identify target populations for lifestyle interventions to effectively prevent diabetes in a real‐world setting.

Methods

The Japan Diabetes Outcome Intervention Trial‐1, a prospective, cluster‐randomized controlled trial, was launched to test if year‐long telephone‐delivered lifestyle support by health professionals can prevent the development of type 2 diabetes (T2D) in people with impaired fasting glucose (IFG) identified at health check‐ups. A total of 2607 participants aged 20‐65 years with IFG were randomized to an intervention arm (n = 1240) or a control arm (n = 1367). We performed subgroup analysis to examine the effects of the intervention on the incidence of T2D in participants with body mass index (BMI) ≥25, metabolic syndrome (MetS), and non‐alcoholic or alcoholic elevated liver enzymes at the baseline. Cox regression analysis adjusted for sex was used to calculate the hazard ratios (HRs).

Results

In addition to IFG, the presence of BMI ≥25, MetS, and elevated liver enzymes increased the incidence of diabetes by two‐ or three‐fold. During a median follow‐up period of 4.9 years, only the non‐alcoholic elevated liver enzyme group showed a low incidence rate owing to lifestyle interventions (adjusted HR: 0.42, 95% confidence interval: 0.18‐0.98).

Conclusion

The results suggest that people who have IFG and non‐alcoholic elevated liver enzymes are a good target population for lifestyle interventions to effectively reduce the incidence of diabetes in a real‐world setting.

Effects of a Chrononutrition-Based Mobile App Intervention on Meal Timings and Weight Changes in Adults

Objectives

Evidence from nutrition studies that consider the circadian system (chrononutrition) has rapidly accumulated. The aim of this study is to evaluate the effects of a chrononutrition-based mobile application (app) on meal timings and weight changes in participants categorized as lean, normal weight, overweight, and obese.

Methods

A total of 3,816 adults aged 19–66 (mean age: 40.4 ± 9.8 years, male: 72.1%) were recruited. The app, named “Reborn Magic,” enabled self-monitoring through the use of process motivators including gamification. The primary outcome was weight changes after a 4-week intervention. Other outcomes include waking time; timing of eating breakfast, lunch, and dinner; and bedtime on weekends and holidays. Physical condition score including feeling refreshed after waking up, concentration in the afternoon, and vitality after work were measured.

Results

Of the 3,816 adults enrolled in the Reborn Magic study, 1,835 completed the pre-post assessment (48.1% retention rate). Age was negatively correlated with waking time and dinner timing but had no correlation with the timing of breakfast, lunch, and going to bed. The rates of inappropriate meal time were 32.9%, 34.2%, and 61%, respectively. The time lag improved after the intervention (80.6 ± 71.9→69.0 ± 70.3, 83.8 ± 59.9→72.7 ± 62.0, 26.8 ± 49.9→18.1 ± 44.6, and 8.7 ± 73.9→40.7 ± 55.0 min, respectively), although they did not improved except bed time on weekends. Physical condition scores (out of 10) were significantly increased (6.6 ± 2.3 to 8.2 ± 2.0 points). Significant weight loss was observed in participants with overweight and obesity (-0.33 ± 1.23 and –0.49 ± 1.39 kg, respectively), while in participants in the lean category, significant weight gain was observed (+0.37 ± 0.99 kg). However, there were no weight changes in participants with normal weight.

Conclusions

These results demonstrate the chrononutrition-based mobile app's efficacy with regard to adjusting weight through the improvement of circadian rhythm. Further studies, including randomized controlled trials, are required to confirm these results.

Funding Sources

JSPS KAKENHI

Development and Validation of a Decisional Balance Tool to Assess Perceived Benefits and Barriers of Vegetable Intake in Adults

Objectives

Inverse associations are observed between vegetable intake and diabetes, cardiovascular disease, cancer, and all-cause mortality. The decisional balance tool is a promotional tool targeting the perceived pros and cons of behavior adoption. The aim of this study was to develop and validate a decisional balance tool to assess the perceived benefits and barriers of vegetable intake in adults.

Methods

A total of 379 adults aged 20–70 years (mean age, 30.5 ± 12.6 years; male, 21.4%) were enrolled in this study. Demographic parameters (age, body mass index, marital status, employment status, house income, and family members), vegetable intake, stage of changes (precontemplation, contemplation, preparation, action/maintenance), the importance of change, and confidence (self-efficacy) were measured using a web-based survey. After constructing an initial item pool based on expert consultations and existing scales, Phase 1 of the study was launched, involving an exploratory factor analysis of 15 perceived benefits and 15 perceived barriers. The participants responded on a 5-point Likert scale. An exploratory factor analysis was conducted, and internal validity, external validity, and reliability were tested. Decisional balance was estimated by subtracting the barriers from the perceived benefits.

Results

The final 24 items had a two-domain structure in perceived benefits (“pleasure” and “healthy”) and a three-domain structure in perceived barriers (“not attractive,” “low priority,” and “hard to get”) with high internal consistency (Cronbach's alpha = 0.82, 0.79, 0.82, 0.76, and 0.76, respectively). The test–retest reliability study showed substantial values of the intraclass correlation coefficient (0.77). The perceived benefits score was positively correlated with vegetable servings, although the perceived barrier score was negatively correlated with vegetable servings (Spearman's correlation = 0.324 and −0.435, respectively). Significant and meaningful differences were observed between the stages of change in the pros and cons of vegetable intake (p for trend = 0.016).

Conclusions

These findings suggest that this questionnaire is a valid, reliable tool for assessing the pros and cons of vegetable intake in adults.

Funding Sources

JSPS KAKENHI.

Development and Validation of the Continuous Subcutaneous Insulin Infusion-Related Quality-of-Life (CSII-QOL) Scale

Background: Continuous subcutaneous insulin infusion (CSII) is associated with improved glycemic control, a reduced incidence of hypoglycemia, and improved quality of life (QOL). To date, however, there has been no QOL scale specific to CSII. The objective of this study was to develop and validate a scale to measure CSII-QOL for people with type 1 diabetes (T1D). Methods: A total of 50 people with T1D aged ≥15 years who used CSII (28% males; age, 47.6 ± 17.0 years; duration of diabetes, 14.7 ± 9.7 years; duration of CSII use, 6.1 ± 3.3 years; HbA1c, 7.4% ± 0.8%) took part in the CSII-QOL study. Twenty-eight potential CSII-QOL items were developed in a combined approach consisting of semistructured patient interviews, expert input, and a literature search. The resulting CSII-QOL was tested for factor analysis, validity, reliability, and influencing factors. Results: The final 25-item questionnaire had a 3-domain structure ("convenience," "social restriction," and "psychological problems"), high internal consistency (Cronbach's alpha = 0.870), and substantial test-retest reliability (intraclass correlation coefficient = 0.65). The CSII-QOL score was correlated negatively with the Problem Areas in Diabetes score. Conclusion: The CSII-QOL is the first CSII-related QOL scale for people with T1D. This short, validated, and reliable instrument might potentially be useful in future clinical studies and routine clinical patient care. Further validation is required to confirm these issues because of the small and potentially biased sample (UMIN-CTR: UMIN000031595).

The Effect of High-concentration Insulin Glarigine on the Quality of Life of Patients with Type 2 Diabetes Mellitus: A Pre-post Study (HIGH-QOL STUDY)

Objective We compared the pain accompanying the injection of high-concentration (300 units/mL) insulin glargine (U300G) with that accompanying the injection of conventional (100 units/mL) insulin glargine (U100G). Methods U100G was switched to U300G at basically the same dosage. Visual analog scales were used to assess the quality of life (QOL). The primary outcome was the change in the pain accompanying injections in those using ≥30 units of U100G compared with those using <30 units at baseline. Standardized mean differences (Cohen's d) were used to measure the effect size. Patients Adult patients with type 2 diabetes mellitus using U100G. Results One hundred and eight patients were recruited. The numbers of patients who used U100G at ≥30 units, 20 to <30 units, 10 to <20 units, and <10 units were 13, 14, 34, and 47, respectively. The improvement in the pain score was not significant for ≥30 units compared with <30 units (-50.3±24.0 vs. -40.4±28.5, p=0.25, d=0.38), but a significant difference was observed for ≥20 units compared with <20 units (-50.8±22.7 vs. -38.4±29.1, p=0.03, d=0.48), as well as for ≥10 units compared with <10 units (-48.1±25.0 vs. -33.0±29.7, p<0.01, d=0.56). When all patients were analyzed together, significant improvements in the pain score (-41.5±28.0, p<0.01), ease of use score (-37.5±32.2, p<0.01), force needed to inject score (-46.5±28.6, p<0.01), and preference for U300G compared with U100G score (-45.8±33.1, p<0.01) were observed. Conclusion There is possibility that switching from U100G to U300G might be associated with better QOL for patients who require insulin glargine injections. To prove this hypothesis, a randomized controlled trial (preferably double-blinded) will be required in the future.

The study of metabolic improvement by nutritional intervention controlling endogenous GIP (Mini Egg study): a randomized, cross-over study

Background

Given the major role of glucose-dependent insulinotropic polypeptide (GIP) in the regulation of adiposity, this study examined the effects induced by a diet based on the Japanese tradition (SMART WASHOKU) on the visceral fat area (VFA) and GIP secretions.

Methods

Overweight/obese men (n = 21; mean age, 41.0 ± 9.0 years; mean BMI, 25.2 ± 2.0 kg/m²) without diabetes were placed on either a SMART WASHOKU or control meal for 2 weeks, in a randomized, cross-over setup with a four-week washout period.

Results

For the meal tolerance test, blood samples were collected at 0, 30, 60, 120, 180, and 240 min post-meal, followed by measuring blood glucose, insulin, GIP, and glucagon-like peptide-1 (GLP-1) levels. Relative to a control meal, SMART WASHOKU meal yielded significantly lower plasma postprandial GIP concentrations (AUC: 700.0 ± 208.0 vs. 1117.0 ± 351.4 pmol/L・4 h, P < 0.05); however, between meals, there was no significant difference in the levels of GLP-1, peptide YY, and ghrelin. Compared to the control meal, SMART WASHOKU intervention significantly reduced VFA and the levels of LDL-cholesterol, triglyceride, and HbA1c after the chronic meal intervention.

Conclusions

In conclusion, a SMART WASHOKU meal may decrease VFA and improve metabolic parameters in overweight/obese men, possibly via suppressing GIP secretion.

An optimal condition for the evaluation of human brown adipose tissue by infrared thermography

Brown adipose tissue (BAT) is responsible for non-shivering thermogenesis and is an attractive therapeutic target for combating obesity and related diseases. Human BAT activity has been evaluated by ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸FDG-PET/CT) under acute cold exposure, but the method has some serious limitations, including radiation exposure. Infrared thermography (IRT) may be a simple and less-invasive alternative to evaluate BAT activity. In the present study, to establish an optimal condition for IRT, using a thermal imaging camera, skin temperature was measured in the supraclavicular region close to BAT depots (T_scv) and the control chest region (T_c) in 24 young healthy volunteers. Their BAT activity was assessed as the maximal standardized uptake value (SUV_max) by ¹⁸FDG-PET/CT. Under a warm condition at 24–27°C, no significant correlation was found between the IRT parameters (T_scv, T_c,, and the difference between T_scv and T_c,, Δtemp) and SUV_max, but 30–120 min after cold exposure at 19°C, T_scv and Δtemp were significantly correlated with SUV_max (r = 0.40–0.48 and r = 0.68–0.76). Δtemp after cold exposure was not affected by mean body temperature, body fatness, and skin blood flow. A lower correlation (r = 0.43) of Δtemp with SUV_max was also obtained when the participant’s hands were immersed in water at 18°C for 5 min. Receiver operating characteristic analysis revealed that Δtemp after 30–60 min cold exposure can be used as an index for BAT evaluation with 74% sensitivity, 92% specificity, and 79% diagnostic accuracy. Thus, IRT may be useful as a simple and less-invasive method for evaluating BAT, particularly for large-scale screening and longitudinal repeat studies.

Prevention of Metabolic Syndrome by Telephone-Delivered Lifestyle Intervention in a Real-World Setting: Sub-Analysis of a Cluster-Randomized Trial

Background: Evidence of the long-term benefits of telephone-delivered lifestyle interventions is limited. This study investigated the ability of telephone-delivered lifestyle intervention to reduce the incidence of metabolic syndrome (MetS) in subjects diagnosed with impaired fasting glucose (IFG) during health checkups. Methods: Our subjects were participants in the Japan Diabetes Outcome Intervention Trial-1 (J-DOIT1), a prospective, cluster-randomized controlled trial designed to investigate whether goal-focused lifestyle coaching over the telephone can effectively reduce the incidence of type 2 diabetes development in high-risk individuals in a primary health care setting. We extracted 753 and 844 J-DOIT1 participants from the intervention and controls arms, respectively, who had IFG but did not meet the MetS criteria at baseline. The intervention arm received goal-focused lifestyle support delivered by health care providers via telephone over a 1-year period. The endpoint was the development of incident MetS, defined based on the Adult Treatment Panel III criteria modified for Japan. Results: During the median follow-up period of 4.9 years, 8.0% of the intervention arm and 12.0% of the control arm developed MetS. Overall, the hazard ratio (HR) for the development of MetS was 0.75 [95% confidence interval (CI), 0.52-1.09; P = 0.14] in the intervention arm. However, the HR in overweight or obese [body mass index (BMI) ≥23 kg/m²] individuals was significantly reduced to 0.63 (95% CI, 0.41-0.95; P = 0.029), but not in lean (BMI <23 kg/m²) individuals. Conclusion: Telephone-delivered lifestyle intervention effectively reduced the incidence of MetS in overweight and obese subjects in a real-world setting. Clinical trial registration number: UMIN000000662 (registered March 30, 2007; https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000000798).

Prevalence and Risk Factors of Elevated Liver Enzymes in Japanese Women With Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is a common endocrine disorder among reproductive-aged women. While PCOS is associated with an increased risk of obesity and insulin resistance, little is known regarding the prevalence of and risk factors for nonalcoholic fatty liver disease (NAFLD) among Japanese women with PCOS. We estimated the prevalence of and risk factors for elevated liver enzymes, as the index of NAFLD, in Japanese women with PCOS.

Methods

We retrospectively reviewed 102 reproductive-aged women who visited the Department of Gynecology, Kyoto Medical Center in Japan from January 2000 to September 2016. Inclusion criterion was confirmed diagnosis of PCOS using International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10) codes. Exclusion criteria were women with a history of liver diseases, missing body mass index (BMI) and serum alanine aminotransferase (ALT) data, and pregnancy. Data regarding age; BMI; and levels of blood glucose, serum lipid, liver enzymes, and sex hormones were obtained from medical records. Elevated liver enzymes was defined as ALT > 19 IU/L. Optimal cutoffs for risk factors for elevated liver enzymes were calculated to determine predictors of elevated liver enzymes using area under the curve (AUC) by receiver-operating characteristics (ROC).

Results

The prevalence of elevated liver enzymes was 33.3%. BMI was significantly higher in PCOS patients than in those without elevated liver enzymes (25.3 vs. 20.7 kg/m², P < 0.05). ROC analyses were performed using BMI and blood glucose and testosterone levels because BMI and blood glucose showed differences between the groups and testosterone is related to fatty liver. AUC of the model including BMI and blood glucose and testosterone levels was 0.861 (sensitivity, 66.7%; specificity, 100%).

Conclusions

These findings suggest that elevated liver enzymes are common in women with PCOS. An algorism using BMI and blood glucose and testosterone levels might be useful to determine elevated liver enzymes in women with PCOS. Our finding may be useful for the study of NAFLD among Japanese women with PCOS since several previous studies have indicated elevated liver enzymes to be related to the potential presence of NAFLD. Further examination, including abdominal ultrasonography and/or liver biopsy data, is required to confirm these results.

Mass Contents of Inositol 1,4,5-Trisphosphate and 1,2-Diacylglycerol in Human Platelets Stimulated with a Thromboxane Analogue and Thrombin

Mass contents of inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol (DG) were measured in U46619-stimulated human platelets. 1 µM of U46619 induced maximum responses in aggregation, 5-hydroxytryptamine (5HT) secretion and increase in intracellular free Ca2+ concentration ([Ca2+]i). Aggregation was almost comparable to that induced by maximal dose (1 U/ml) of thrombin, while 5HT release was almost half. The initial [Ca2+]i peak in response to U46619 was about half of thrombin stimulation. Production of IP3 and DG was, however, less than one tenth of that seen in thrombin stimulation. The profile (time course and concentration-dependency) of IP3 formation did not correlate with that of [Ca2+]i, suggesting that U46619 stimulates IPs-dependent and -independent Ca2+ mobilization. DG production was small but sustained for more than 5 min. These findings support the recent hypothesis that aggregation is regulated by a delayed accumulation of DG. The low level of 5HT secretion could be explained by the low production of second messengers, IP3 and DG.

Effects of a Low Advanced Glycation End Products Diet on Insulin Levels: The Feasibility of a Crossover Comparison Test

Background

Advanced glycation end products (AGEs) are associated with diabetes mellitus. Digested food-derived AGEs have been implicated in the pathogenesis of AGE-related disorders, and restricting diet-derived AGEs improves insulin resistance in animal models. The AGE content in foods changes according to cooking method, and it is higher in baked or oven-fried foods than in those prepared by steaming or simmering. Here, we examined the feasibility of crossover comparison tests for determining how different cooking methods (normal diet vs. low-AGE diet) affect insulin levels in non-diabetic Japanese subjects.

Methods

Five adult men and women (age, 41 ± 7 years; body mass index (BMI), 21.7 ± 2.6 kg/m²) were enrolled. The following dietary regimen was used: days 1 - 3, control meal; day 4, test meal (normal diet vs. low-AGE diet); day 5, washout day; and day 6, test meal. On days 4 and 6, blood samples were collected before and at 2, 4, and 6 h after meals.

Results

Blood levels of N-(carboxymethyl) lysine (CML) increased with dietary intake, but the increase was similar for the normal diet and low-AGE diet groups. Mean plasma glucose, insulin, triglycerides (TG), and CML did not differ significantly between the two groups. The area under the curve (AUC) for insulin levels was lower in the low-AGE diet group (d = 0.8). The sample size calculated from the effect size of the insulin AUC change was 22.

Conclusions

Twenty-two subjects may be needed to investigate the changes in clinical parameters attributable to cooking method in non-diabetic Japanese subjects.

Femtosecond Yb:CaGdAlO4 thin-disk oscillator

A mode-locked thin-disk laser based on Yb:CALGO is demonstrated for the first time. At an average output power of 28 W we obtained pulses with a duration of 300 fs and a pulse energy of 1.3 μJ. 197 fs pulses with 0.9 μJ of energy were achieved at an average output power of 20 W. The shortest pulse duration measured in our experiments was 135 fs with a spectrum centered at 1043 nm. The experiments also revealed a very broad tunability from 1032 to 1046 nm with sub-200 fs pulses.

Effect of E5510 on anastomotic intimal hyperplasia and platelet aggregation in dogs

We examined the effect of an antiplatelet agent, E5510, which inhibits both platelet aggregation and release of platelet-derived growth factor (PDGF), on anastomotic intimal hyperplasia and platelet aggregation. Twenty Beagle dogs underwent infrarenal aortic reconstruction with an expanded polytetrafluoroethylene (ePTFE) graft 5 mm in diameter and 3 cm long. The dogs were divided into three groups: placebo (control group, 7 dogs), E5510 1 mg/day (1-mg group, 6 dogs), and E5510 4 mg/day (4-mg group, 7 dogs). E5510 was administered orally 2 h before operation and once daily for 3 months after operation. Grafts were harvested 3 months after operation. All 13 grafts in the treated groups remained patent without evidence of intimal hyperplasia, whereas only 4 of 7 grafts (57%) remained patent in the control group, including 1 graft with > 50% stenosis. Three occluded grafts showed severe intimal hyperplasia at the anastomoses. The platelet aggregation ratio (PAR) with collagen (100 micrograms/ml) before drug administration at 3 months in the 4-mg group was significantly lower than that in the control and 1-mg groups. PAR after drug administration at 3 months in the 1- and 4-mg groups was significantly lower than that in the control group. Intimal thickness at the distal anastomosis was 817 +/- 190 microns in the control group, 240 +/- 80 microns in the 1-mg group, and 197 +/- 28 microns in the 4-mg group. Intimal thickness in the control group was significantly greater than that in the 1- and 4-mg groups. Smooth muscle cell (SMC) values in the intima at the distal anastomosis were 65.6 +/- 4.4% extinction (%E) in the control group, 47.6 +/- 3.4%E in the 1-mg group, and 51.3 +/- 3.5%E in the 4-mg group. SMC value in the control group was significantly greater than that in the 1- and 4-mg groups. E5510 inhibited PAR and reduced the degree of anastomotic intimal hyperplasia.

Multiple elements in the 5' untranslated region down-regulate c-sis messenger RNA translation

Expression of the platelet derived growth factor (PDGF) B-chain, the product of the c-sis proto-oncogene, is regulated both at the transcriptional and translational level. Previous studies have shown that the long 5' untranslated region (UTR) of the c-sis mRNA strongly inhibits synthesis of the PDGF-B chain. However, the assignments of down-regulatory regions within the 5' UTR were ambiguous. Expression of several site-directed point and deletion mutants of the 5' UTR of the c-sis mRNA in COS1 cells revealed that the UTR inhibited PDGF-B chain synthesis in a more complex manner than indicated by the previous studies. Abrogation of the three upstream short open reading frames by mutating each of the AUGs did not have any effect on the synthesis of the PDGF-B chain. Expression of deletion mutants revealed two partially overlapping regions, nucleotides 1-651 and 475-1022, each of which independently inhibited c-sis mRNA translation as effectively as the entire 5' UTR. Each of these regions contains a potentially strong stem-loop structure and a GC-rich element. These elements of the alternate down-regulatory regions could interact within the same region and/or with the elements of the other regulatory region to block c-sis mRNA translation. We show, in contrast to the previous reports, that the inhibition of c-sis mRNA translation cannot be attributed exclusively to any particular predicted secondary structure or a GC-rich element within the 5' UTR.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of sugar-binding sites in Staphylococcus aureus using gold-labeled neoglycoprotein

We studied post- and pre-embedding staining of sugar-binding sites on thin sections of Staphylococcus aureus with an electron microscopic neoglycoprotein-gold technique. Although gold particles of cellobiosyl bovine serum albumin (BSA)-glycosylated BSA-, lactosyl BSA-, and melibiosyl BSA-gold did not label, heavy labeling of N-acetylglucosaminide-BSA-gold was observed in both the cell wall and the cytoplasm on Spurr-embedded thin sections of S. aureus. Inhibition of labeling with wheat germ agglutinin-biotin and N-acetylglucosaminidase indicated that the labeling was due to N-acetylglucosamine. These data suggested that molecules that bind specifically with N-acetylglucosamine occur in the cell wall and cytoplasm of S. aureus. Pre-embedding staining revealed that these molecules are abundant at the surface of the cell wall and that the abundance differs depending on the bacterial strain. An N-acetylglucosamine-specific lectin-like substance, glucosaminidase, and toxins are proposed as candidates for molecules responsible for the labeling, and the possible functional significance of the findings is discussed briefly.

Acquired nephrogenic diabetes insipidus secondary to distal renal tubular acidosis and nephrocalcinosis associated with Sjögren's syndrome

A 52-year-old woman was referred to our hospital because of 16-year history of polyuria and polydipsia. Hyposthenuria, hyperchloremic metabolic acidosis and the inabilities to acidify the urine after acid-loading test and to concentrate the urine in responses to water-deprivation and antidiuretic hormone administration allowed us to diagnose renal tubular acidosis and nephrogenic diabetes insipidus. Radiographic examinations revealed bilateral nephrocalcinosis. The patient was also found to have clinical and laboratory findings characteristic for Sjögren's syndrome. Thus the longstanding, poorly monitored distal renal tubular acidosis associated with Sjögren's syndrome was considered to result in very rare renal complications-nephrocalcinosis and nephrogenic diabetes insipidus. In patients with renal tubular acidosis and/or nephrogenic diabetes insipidus of unknown etiology, therefore, Sjögren's syndrome should be considered as one of primary disorders.

Mass contents of inositol 1,4,5-trisphosphate and 1,2-diacylglycerol in human platelets stimulated with a thromboxane analogue and thrombin

Mass contents of inositol 1,4,5-trisphosphate (IP3) and 1,2-diacylglycerol (DG) were measured in U46619-stimulated human platelets. 1 microM of U46619 induced maximum responses in aggregation, 5-hydroxytryptamine (5HT) secretion and increase in intracellular free Ca2+ concentration ([Ca2+]i). Aggregation was almost comparable to that induced by maximal dose (1 U/ml) of thrombin, while 5HT release was almost half. The initial [Ca2+]i peak in response to U46619 was about half of thrombin stimulation. Production of IP3 and DG was, however, less than one tenth of that seen in thrombin stimulation. The profile (time course and concentration-dependency) of IP3 formation did not correlate with that of [Ca2+]i, suggesting that U46619 stimulates IP3-dependent and -independent Ca2+ mobilization. DG production was small but sustained for more than 5 min. These findings support the recent hypothesis that aggregation is regulated by a delayed accumulation of DG. The low level of 5HT secretion could be explained by the low production of second messengers, IP3 and DG.

Thrombin induces a biphasic 1,2-diacylglycerol production in human platelets

The 1,2-diacylglycerol (DAG) mass content was measured in thrombin-stimulated human platelets. Thrombin stimulates a biphasic accumulation of DAG, with an early phase reaching a peak at 10 s and a later phase reaching a peak at 2-3 min. The time course of first-phase DAG production corresponded well to that of Ins(1,4,5)P3 formation, which was rapid and transient. The second phase of DAG accumulation occurred after the level of Ins(1,4,5)P3 returned to nearly basal. Thrombin stimulated the decrease in PtdIns and phosphatidylcholine contents. The source of second-phase DAG was examined in platelets prelabelled with three radioactive fatty acids, i.e. arachidonic, palmitic and myristic. Thrombin stimulated the increase in radioactivity of DAG with decline of PtdIns in platelets labelled with [3H]arachidonic acid or [3H]palmitic acid, in which PtdIns was considerably labelled. In contrast, significant accumulation of [3H]DAG was not observed in [3H]myristic acid-labelled platelets, in which PtdIns was poorly labelled. In platelets prelabelled with [3H]inositol, an increase in InsP in response to thrombin was seen for more than 5 min. In contrast, upon stimulation, significant increases in [3H]phosphocholine and [3H]choline were not observed in [methyl-3H]choline-labelled platelets. Thrombin induced a small production of phosphatidylethanol, when ethanol was present during stimulation. However, the formation of DAG and phosphatidic acid was not significantly affected by ethanol. These results suggest that thrombin stimulates a biphasic accumulation of DAG, initially from PtdInsP2 and later from PtdIns in human platelets.

Mechanism of arachidonic acid liberation in platelet-activating factor-stimulated human polymorphonuclear neutrophils

Upon stimulation of human polymorphonuclear neutrophils with platelet-activating factor (PAF), arachidonic acid (AA) is released from membrane phospholipids. The mechanism for AA liberation, a key step in the synthesis of biologically active eicosanoids, was investigated. PAF was found to elicit an increase in the cytoplasmic level of free Ca2+ as monitored by fluorescent indicator fura 2. When [3H] AA-labeled neutrophils were exposed to PAF, the enhanced release of AA was observed with a concomitant decrease of radioactivity in phosphatidylinositol and phosphatidylcholine fractions. The inhibitors of phospholipase A2, mepacrine and 2-(p-amylcinnamoyl)-amino-4-chlorobenzoic acid, effectively suppressed the liberation of [3H]AA from phospholipids, indicating that liberation of AA is mainly catalyzed by the action of phospholipase A2. The extracellular Ca2+ is not required for AA release. However, intracellular Ca2+ antagonists, TMB-8 and high dose of quin 2/AM drastically reduced the liberation of AA induced by PAF, indicating that Ca2+ is an essential factor for phospholipase A2 activation. PAF raised the fluorescence of fura 2 at concentrations as low as 8 pM which reached a maximal level about 8 nM, whereas more than nM order concentrations of PAF was required for the detectable release of [3H]AA. Pretreatment of neutrophils with pertussis toxin resulted in complete abolition of AA liberation in response to PAF. However, the fura 2 response to PAF was not effectively inhibited by toxin treatment. In human neutrophil homogenate and membrane preparations, guanosine 5'-O-(thiotriphosphate) stimulated AA release and potentiated the action of PAF. Guanosine 5'-O-(thiodiphosphate) inhibited the effects of guanosine 5'-O-(thiotriphosphate). These results suggest several points: 1) PAF stimulates human polymorphonuclear neutrophils to liberate AA mainly by the action of phospholipase A2; 2) Ca2+ mobilization alone is not sufficient to stimulate AA release, although Ca2+ is the important factor for phospholipase A2 activation; and 3) a pertussis toxin-sensitive GTP-binding protein may be implicated in activation of phospholipase A2.

Mechanism of arachidonic acid liberation in platelet-activating factor-stimulated human polymorphonuclear neutrophils

Upon stimulation of human polymorphonuclear neutrophils with platelet-activating factor (PAF), arachidonic acid (AA) is released from membrane phospholipids. The mechanism for AA liberation, a key step in the synthesis of biologically active eicosanoids, was investigated. PAF was found to elicit an increase in the cytoplasmic level of free Ca2+ as monitored by fluorescent indicator fura 2. When [3H] AA-labeled neutrophils were exposed to PAF, the enhanced release of AA was observed with a concomitant decrease of radioactivity in phosphatidylinositol and phosphatidylcholine fractions. The inhibitors of phospholipase A2, mepacrine and 2-(p-amylcinnamoyl)-amino-4-chlorobenzoic acid, effectively suppressed the liberation of [3H]AA from phospholipids, indicating that liberation of AA is mainly catalyzed by the action of phospholipase A2. The extracellular Ca2+ is not required for AA release. However, intracellular Ca2+ antagonists, TMB-8 and high dose of quin 2/AM drastically reduced the liberation of AA induced by PAF, indicating that Ca2+ is an essential factor for phospholipase A2 activation. PAF raised the fluorescence of fura 2 at concentrations as low as 8 pM which reached a maximal level about 8 nM, whereas more than nM order concentrations of PAF was required for the detectable release of [3H]AA. Pretreatment of neutrophils with pertussis toxin resulted in complete abolition of AA liberation in response to PAF. However, the fura 2 response to PAF was not effectively inhibited by toxin treatment. In human neutrophil homogenate and membrane preparations, guanosine 5'-O-(thiotriphosphate) stimulated AA release and potentiated the action of PAF. Guanosine 5'-O-(thiodiphosphate) inhibited the effects of guanosine 5'-O-(thiotriphosphate). These results suggest several points: 1) PAF stimulates human polymorphonuclear neutrophils to liberate AA mainly by the action of phospholipase A2; 2) Ca2+ mobilization alone is not sufficient to stimulate AA release, although Ca2+ is the important factor for phospholipase A2 activation; and 3) a pertussis toxin-sensitive GTP-binding protein may be implicated in activation of phospholipase A2.

Primary role of calcium ions in arachidonic acid release from rat platelet membranes. Comparison with human platelet membranes

The liberation of arachidonic acid (AA) was investigated in platelet membranes prelabelled with [3H]AA. In rat platelet membranes, Ca2+ at concentrations over several hundred nanomolar induced [3H]AA release, with a concurrent decrease in 3H radioactivity of phosphatidylethanolamine and phosphatidylcholine. Some 4-6% of total radioactivity incorporated into platelet membrane lipids was released at 1-10 microM-Ca2+, which is nearly equivalent to that attained in agonist-stimulated platelets. Formation of lysophospholipids in [3H]glycerol-labelled membranes and decrease in [3H]AA liberated by the phospholipase A2 inhibitors mepacrine and ONO-RS-082 suggest that [3H]AA release is mainly catalysed by phospholipase A2. In intact platelets agonist-stimulated [3H]AA release was markedly decreased in the absence of extracellular Ca2+ or in the presence of the intracellular Ca2+ chelator quin 2. These results indicate that in rat platelets the rise of intracellular Ca2+ plays a primary role in the activation of phospholipase A2. In contrast, Ca2+ even at high millimolar concentrations did not effectively stimulate [3H]AA release in human platelet membranes. Thus factor(s) additional to or independent of Ca2+ is required for the liberation of AA in human platelets.

A role of diacylglycerol kinase in stimulus-secretion coupling of human platelets. Dissociation of serotonin secretion from Ca2+ mobilization

The addition of diacylglycerol kinase inhibitor, R 59 022 (6-[2-[4-[(4-fluorophenyl)phenylmethylene]-1-piperidinyl]-7-methyl - 5H-thiazolo[3,2-alpha]pyrimidin-5-one) resulted in a marked accumulation of diacylglycerol in thrombin-stimulated platelets. Release of arachidonic acid induced by thrombin was not affected by the inhibitor. In intact platelets, the conversion of exogenously added 1-oleoyl-2-acetylglycerol to 1-oleoyl-2-acetylphosphatidic acid also was inhibited by the inhibitor. We further investigated the effects of the inhibitor on serotonin secretion and Ca2+ mobilization in thrombin-activated platelets. R 59 022 potentiated serotonin secretion induced by thrombin or 1-oleoyl-2-acetylglycerol. On the other hand, the thrombin-induced increase in cytosolic free Ca2+ concentration measured with aequorin or Quin2 was found to be depressed by R 59 022. These results indicate that diacylglycerol kinase has an important role in regulation of serotonin secretion and that Ca2+ mobilization may not be tightly coupled to serotonin secretion.

Guanine nucleotides stimulate arachidonic acid release by phospholipase A2 in saponin-permeabilized human platelets

GTP or GTP gamma S alone caused low but significant liberation of arachidonic acid in saponin-permeabilized human platelets but not in intact platelets. GTP or GTP gamma S also enhanced thrombin-induced [3H]arachidonic acid release in permeabilized platelets. Inhibitors of the phospholipase C (neomycin)/diacylglycerol lipase (RHC 80267) pathway for arachidonate liberation did not reduce the [3H]arachidonic acid release. The loss of [3H]arachidonate radioactivity from phosphatidylcholine was almost equivalent to the increase in released [3H]arachidonic acid, suggesting the hydrolysis of phosphatidylcholine by phospholipase A2. The effect of GTP gamma S was greater at lower Ca2+ concentrations. These data indicate that the release of arachidonic acid by phospholipase A2 in saponin-treated platelets may be linked to a GTP-binding protein.

Ultrastructural localization of carbohydrates on thin sections of Staphylococcus aureus with silver methenamine and wheat germ agglutinin-gold complex

Postembedding staining of intracellular carbohydrates on thin sections of Staphylococcus aureus was studied by the silver methenamine and the wheat germ agglutinin-gold techniques. Staining of silver grains was observed on both the cell wall and the cross wall. The staining was interpreted to be due to teichoic acid. Labeling by wheat germ agglutinin-gold particles was observed on both the cell wall and the cross wall, and the staining pattern resembled that of silver methenamine staining. Therefore, the labeling was considered to be due to N-acetylglucosamine of teichoic acid. The combination of two types of cytochemical techniques was useful to localize and characterize the carbohydrates of the bacterial cell.

Polymyxin B binding sites in Escherichia coli as revealed by polymyxin B-gold labeling

A complex of polymyxin B, bovine serum albumin, and colloidal gold was prepared and used for the ultrastructural localization of polymyxin B binding sites on thin sections of Epon-embedded Escherichia coli cells. Gold particles were found on the outer membrane of E. coli, which is consistent with reported biochemical findings. We concluded that gold labeling with polymyxin B is useful in localizing the binding sites of polymyxin.

Aminoglycoside binding sites in Escherichia coli as revealed by neomycin-gold labeling

A cytochemical technique for demonstration of neomycin binding sites by electron microscopy was developed and applied to Escherichia coli. Neomycin was conjugated chemically with bovine serum albumin (BSA). Colloidal gold was coated with the conjugated neomycin-BSA. The neomycin-BSA-gold was applied to thin sections of Epon-embedded E. coli and examined. Gold particles were observed on the outer membrane and the cytoplasmic membrane of E. coli. It was probably the ribosomes that were being labeled in the cytoplasm. Different cytochemical controls, including a number of inhibition tests and the use of BSA-gold, proved the specificity of this cytochemical technique and provided the biochemical significance of the observations.

B lymphocyte differentiation and suppressor activity by T lymphocytes derived from neonatal and sucking piglets

The capacity of porcine neonatal T and B lymphocytes was studied employing a protein A haemolytic plaque assay. Only a few peripheral blood lymphocytes (PBL) from newborn piglets differentiated into immunoglobulin (Ig)-producing cells on stimulation by pokeweed mitogen (PWM). Newborn PBL also suppressed the differentiation of adult PBL into Ig-producing cells. This suppressive effect existed in T-cell enriched populations and appeared to be equally effective in the generation of IgG and IgM-producing cells. When newborn B lymphocytes were cocultured with T lymphocytes from adults in the PWM system, their differentiation into IgG and IgM-producing cells was enhanced. No such enhancement was seen in cocultures of newborn T and B lymphocytes. The generation of Ig-producing cells in PBL from suckling piglets increased with ageing, and reached about half the adult mean at six weeks old. On the other hand, the suppressor activity of T lymphocytes was observed throughout the suckling period, although it gradually decreased with ageing and was not consistently demonstrated by five weeks of age.

Enhancement of bactericidal activity of mouse peritoneal macrophages against Staphylococcus aureus by mouse interferon preparations

The effect of mouse interferon on the bactericidal activity of macrophages against pyogenic cocci was examined. Mouse peritoneal macrophages were cultivated with Staphylococcus aureus in vitro and viable Staphylococcus was recovered by treatment of the mixed macrophage-bacteria culture with sodium dodecyl sulphate (SDS) solution. Results showed that S. aureus was phagocytized and killed by the macrophages. Mouse L cell interferon enhanced the bactericidal activity of macrophages. A mouse brain interferon preparation also enhanced this activity. However, heat-inactivated L cell interferon and heterologous rabbit RK-13 cell interferon and human leukocyte interferon did not enhance it. This suggests that interferon enhances the bactericidal activity of macrophages against S. aureus.