Simultaneous quantification of pyrethroid metabolites in urine of non-toilet-trained children in Japan

BACKGROUND@#Pyrethroid (PYR) insecticides are widely used for controlling various pests. There are two types that differ in terms of usage: agricultural-purpose PYR (agriculture-PYR) and hygiene purpose PYR (hygiene-PYRs). Few studies exist on the exposure to these chemicals in small children. In this study, we conducted biomonitoring of urinary pyrethroid metabolites in 1.5-year-old children throughout the year.@*METHODS@#Study subjects were 1075 children participating in an Aichi regional sub-cohort of the Japan Environment and Children's Study as of 18-month health check-up. The concentrations of four specific hygiene-PYR metabolites including 2,3,5,6-tetrafluoro-1,4-benzenedimethanol (HOCH2-FB-Al), and five common metabolites of hygiene- and agriculture-PYRs including 3-phenoxybenzoic acid (3PBA) and cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DCCA), were measured in urine samples extracted from soiled diapers using a triple quadrupole gas chromatograph-mass spectrometer.@*RESULTS@#The highest detection frequencies were for 3PBA, followed by DCCA, 1R-trans-chrysanthemum dicarboxylic acid, and HOCH2-FB-Al. Among the six metabolites, urinary concentrations were seasonally varied. However, this variation was not observed in the most studied PYR metabolite, 3PBA. Spearman's correlation analysis demonstrated a significant positive correlation between FB-Al and DCCA (r = 0.56) and HOCH2-FB-Al and 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol (r = 0.60).@*CONCLUSIONS@#This biomonitoring survey found widespread and seasonally specific exposure to multiple hygiene- and agriculture-PYRs in 1.5-year-old Japanese children.

A Single Bout of Constant-Load Exercise Test for Estimating the Time Constant of Oxygen Uptake Kinetics in Individuals With Stroke

Objective@#To examine the relationship between the time constant of oxygen uptake kinetics during the onset of exercise (τVO2) estimated from a single exercise bout and that obtained from three averaged exercise bouts in individuals with stroke. @*Methods@#Twenty participants with stroke performed three bouts of a constant-load pedaling exercise at approximately 80% of the workload corresponding to the ventilatory threshold to estimate τVO2. The VO2 data from the first trial of three bouts were used to estimate τVO2 for a single bout. Additionally, data collected from three bouts were ensemble-averaged to obtain τVO2 for three averaged bouts as the criterion. @*Results@#There was a very high correlation between τVO2 for a single bout (34.8±14.0 seconds) and τVO2 for three averaged bouts (38.5±13.4 seconds) (r=0.926, p<0.001). However, τVO2 for a single bout was smaller than that for three averaged bouts (p=0.006). @*Conclusion@#τVO2 for a single bout could reflect the relative difference in τVO2 for three averaged bouts among individuals with stroke. However, it should be noted that τVO2 for a single bout may be underestimated compared to τVO2 for three averaged bouts.

A Single Bout of Constant-Load Exercise Test for Estimating the Time Constant of Oxygen Uptake Kinetics in Individuals With Stroke

Objective@#To examine the relationship between the time constant of oxygen uptake kinetics during the onset of exercise (τVO2) estimated from a single exercise bout and that obtained from three averaged exercise bouts in individuals with stroke. @*Methods@#Twenty participants with stroke performed three bouts of a constant-load pedaling exercise at approximately 80% of the workload corresponding to the ventilatory threshold to estimate τVO2. The VO2 data from the first trial of three bouts were used to estimate τVO2 for a single bout. Additionally, data collected from three bouts were ensemble-averaged to obtain τVO2 for three averaged bouts as the criterion. @*Results@#There was a very high correlation between τVO2 for a single bout (34.8±14.0 seconds) and τVO2 for three averaged bouts (38.5±13.4 seconds) (r=0.926, p<0.001). However, τVO2 for a single bout was smaller than that for three averaged bouts (p=0.006). @*Conclusion@#τVO2 for a single bout could reflect the relative difference in τVO2 for three averaged bouts among individuals with stroke. However, it should be noted that τVO2 for a single bout may be underestimated compared to τVO2 for three averaged bouts.

Intra-individual variations of organophosphate pesticide metabolite concentrations in repeatedly collected urine samples from pregnant women in Japan

BACKGROUND@#Low-dose exposure to organophosphate (OP) insecticides during pregnancy may adversely affect neurodevelopment in children. To evaluate the OP exposure levels, single urine sampling is commonly adopted to measure the levels of dialkylphosphates (DAPs), common OP metabolites. However, the inter-day variations of urinary DAP concentrations within subjects are supposed to be large due to the short biological half-lives of the metabolites, and it is thus considered difficult to accurately assess OP exposure during pregnancy with single sampling. This study aimed to assess intra-individual variations of DAP concentrations and the reproducibility of the exposure dose categorization of OPs according to DAP concentration ranges in pregnant women in Japan.@*METHODS@#Urine samples were collected from 62 non-smoking pregnant women (12-22 weeks of gestation) living in Aichi Prefecture, Japan. First morning void (FMV) and spot urine samples taken between lunch and dinner on the same day were collected on five different days during 2 weeks. The concentrations of DAP and creatinine in urine samples were measured using an ultra performance liquid chromatography with tandem mass spectrometry. Creatinine-adjusted and unadjusted concentrations were used for the intraclass correlation coefficient (ICC) calculations and surrogate category analyses.@*RESULTS@#For all DAP metabolites, the creatinine-adjusted single ICCs exceeded 0.4, indicating moderate reliability. Overall, ICCs of spot urine samples taken in the afternoon were better than those taken as FMV. Surrogate category analyses showed that participants were categorized accurately into four exposure dose groups according to the quartile points.@*CONCLUSION@#This study indicated that a single urine sample taken in the afternoon may be useful in assessing OP exposure as long as the exposure is categorized into quartiles when conducting epidemiological studies in early to mid-pregnant women in Japan.

Di(2-ethylhexyl) phthalate-induced toxicity and peroxisome proliferator-activated receptor alpha: a review

The plasticizer di(2-ethylhexyl) phthalate (DEHP) has been widely used in the manufacture of polyvinyl chloride-containing products such as medical and consumer goods. Humans can easily be exposed to it because DEHP is ubiquitous in the environment. Recent research on the adverse effects of DEHP has focused on reproductive and developmental toxicity in rodents and/or humans. DEHP is a representative of the peroxisome proliferators. Therefore, peroxisome proliferator-activated receptor alpha (PPARα)-dependent pathways are the expected mode of action of several kinds of DEHP-induced toxicities. In this review, we summarize DEHP kinetics and its mechanisms of carcinogenicity and reproductive and developmental toxicity in relation to PPARα. Additionally, we give an overview of the impacts of science policy on exposure sources.

Effects of Resistance Training on Myocardial Infarction Patients in Phase II Cardiac Rehabilitation in Our Hospital / 日本農村医学会雑誌

PURPOSE: The purpose of this retrospective study was to determine the effects of resistance training (RT) on myocardial infarction (MI) patients in phase II cardiac rehabilitation (CR) in our hospital.<br>METHODS: Twenty two outpatients who had participated in the phase II CR program more than three months at least were enrolled in this study. They were divided into control group (n＝8) and RT group (n＝14). We examined changes in the exercise capacity of these two groups. The traditional exercise programs which included aerobics and muscle strength exercise were run on the control group. Changes in exercise load for target heart rate measured with a bicycle ergometer as an indicator of exercise capacity were assessed in each patient 1,3 and 5 months after AMI onset.<br>RESULTS: The amounts of load and target heart rates recorded 1 month after the onset were not significantly different between the two groups. After 3,5 months of CR, the RT group showed no changes in the target heart rate but significant increase of the amount of load. The control group showed no change in the amount of load and target heart rate. In the amount of each load 3 and 5 months after, the RT group was significantly out did the control group.<br>CONCLUSIONS: These results suggested that RT was useful in the improvement of exercise capacity for patients with MI who participated in the phase II CR program provided by our hospital.