ABSTRACT
We have developed experimental equipment for observing the Barnett effect, in which mechanical rotation magnetizes an object, at low temperatures. A sample in a rotor is rotated bidirectionally using a temperature-controlled high-pressure gas. The stray field generated from the sample due to the Barnett effect was detected using a fluxgate magnetic sensor with a sensitivity on the order of several picoteslas, even at low temperatures. By replacing the rotor with a solenoid coil, the magnetic susceptibility of the sample was estimated from the stray field to be of the same order of magnitude as that due to the Barnett effect. The Barnett field was estimated using the dipole model. To assess the performance of the setup at low temperatures, measurements were performed on commercial magnetite (Fe3O4) nanogranules. We confirmed the accordance of the g' factor between the experimental results using the present setup and those of our previous study performed at room temperature.
ABSTRACT
GPR82 is an orphan G protein-coupled receptor (GPCR) that has been implicated in lipid storage in mouse adipocytes. However, the intracellular signaling as well as the specific ligands of GPR82 remain unknown. GPR82 is closely related to GPR34, a GPCR for the bioactive lipid molecule lysophosphatidylserine. In this study, we screened a lipid library using GPR82-transfected cells to search for ligands that act on GPR82. By measuring cyclic adenosine monophosphate levels, we found that GPR82 is an apparently constitutively active GPCR that leads to Gi protein activation. In addition, edelfosine (1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphocholine), an artificial lysophospholipid with a cationic head group that exerts antitumor activity, inhibited the Gi protein activation by GPR82. Two endogenous lysophospholipids with cationic head groups, lysophosphatidylcholine (1-oleoyl-sn-glycero-3-phosphocholine) and lysophosphatidylethanolamine (1-oleoyl-sn-glycero-3-phosphoethanolamine), also exhibited GPR82 inhibitory activity, albeit weaker than edelfosine. Förster resonance energy transfer imaging analysis consistently demonstrated that Gi protein-coupled GPR82 has an apparent constitutive activity that is edelfosine-sensitive. Consistent data were obtained from GPR82-mediated binding analysis of guanosine-5'-O-(3-thiotriphosphate) to cell membranes. Furthermore, in GPR82-transfected cells, edelfosine inhibited insulin-induced extracellular signal-regulated kinase activation, like compounds that function as inverse agonists at other GPCRs. Therefore, edelfosine is likely to act as an inverse agonist of GPR82. Finally, GPR82 expression inhibited adipocyte lipolysis, which was abrogated by edelfosine. Our findings suggested that the cationic lysophospholipids edelfosine, lysophosphatidylcholine and lysophosphatidylethanolamine are novel inverse agonists for Gi-coupled GPR82, which is apparently constitutively active, and has the potential to exert lipolytic effects through GPR82.
Subject(s)
Drug Inverse Agonism , Lysophosphatidylcholines , Animals , Mice , Ligands , Phosphorylcholine , Lysophospholipids/pharmacology , Lysophospholipids/metabolismABSTRACT
Exercise-induced acute kidney injury (EIAKI) is frequently complicated with renal hypouricemia (RHUC). In patients with RHUC, limiting anaerobic exercise can prevent EIAKI. However, it is challenging to reduce exercise intensity in athletes. We herein report a 16-year-old Japanese football player with familial RHUC with compound heterozygous mutations in urate transporter 1 (URAT1) who presented with recurrent EIAKI. As prophylaxis (hydration during exercise) could not prevent EIAKI, febuxostat was initiated. EIAKI was not observed for 16 months despite exercising intensively. Hence, non-purine-selective xanthine oxidoreductase inhibitors may decrease the incidence of EIAKI in athletes with RHUC.
Subject(s)
Acute Kidney Injury , Organic Anion Transporters , Humans , Adolescent , Xanthine Dehydrogenase , Organic Anion Transporters/genetics , Organic Cation Transport Proteins/genetics , Acute Kidney Injury/etiology , Acute Kidney Injury/prevention & control , Enzyme InhibitorsABSTRACT
Renal hypouricemia is a disease caused by the dysfunction of renal urate transporters. This disease is known to cause exercise-induced acute kidney injury, but its mechanism has not yet been established. To analyze the mechanism by which hypouricemia causes renal failure, we conducted a semi-ischemic forearm exercise stress test to mimic exercise conditions in five healthy subjects, six patients with renal hypouricemia, and one patient with xanthinuria and analyzed the changes in purine metabolites. The results showed that the subjects with renal hypouricemia had significantly lower blood hypoxanthine levels and increased urinary hypoxanthine excretion after exercise than healthy subjects. Oxidative stress markers did not differ between healthy subjects and hypouricemic subjects before and after exercise, and no effect of uric acid as a radical scavenger was observed. As hypoxanthine is a precursor for adenosine triphosphate (ATP) production via the salvage pathway, loss of hypoxanthine after exercise in patients with renal hypouricemia may cause ATP loss in the renal tubules and consequent tissue damage.
ABSTRACT
Plasmalogens, functional glycerophospholipids with biological roles in the human body, are associated with various diseases. Although a variety of saturated and/or unsaturated fatty acids in plasmalogens are presumed to have different functions in the human body, there are limited reports validating such functions of plasmalogens. In this study, we focused on the bacterial plasmalogen derived from Selenomonas ruminantium subsp. lactilytica (NBRC No. 103574) with different main species of hydrocarbon chains at the sn-1 position and shorter fatty acids at the sn-2 position than animal plasmalogens. Optimum culture conditions of S. ruminantium for high-yield production of plasmalogens, such as pH and the concentration of caproic acid, were investigated under anaerobic conditions using a 2-L scale jar fermenter. The obtained plasmalogen mainly consisted of the ethanolamine plasmalogen (PlsEtn). The molar ratios of PlsEtn species obtained from S. ruminantium, at sn-1/sn-2 positions, were p16:1/14:0 (68.4%), p16:1/16:1 (29.2%), p16:1/16:0 (0.7%), p16:1/15:0 (0.3%), and p17:1/14:0 (0.3%). Subsequently, duodenal infusion of the emulsion carrying the lipid extracted from S. ruminantium was carried out in lymph duct-cannulated rats. In the lymphatic plasmalogen of rats, the level of PlsEtns with molar ratios p16:1/14:0 and p16:1/16:1, the main species of plasmalogens from S. ruminantium, increased gradually until 3-4 h after lipid injection and then gradually decreased. In addition, the level of PlsEtns with p16:1/20:4 and p16:1/22:6 rapidly increased, peaking at 1-1.5 h and 1.5-2 h after lipid injection, respectively. The increase in the number of PlsEtns with p16:1/20:4 and p16:1/22:6 suggested that 20:4 and 22:6, the main fatty acids at the sn-2 position in the rat lymphatic plasmalogen, were preferentially re-esterified at the sn-2 position, regardless of the types of hydrocarbon chains at the sn-1 position. Thus, we showed that bacterial PlsEtns with "unnatural" structures against rats could be absorbed into the lymph. Our findings provide insights into the association between the chemical structure of plasmalogens and their biological functions in humans.
ABSTRACT
An effective method that can protect radiation-damaged tissues from apoptosis and promote tissue repair has not been reported to date. Hypoxanthine (Hx) is an intermediate metabolite in the purine degradation system that serves as a substrate for ATP synthesis via the salvage pathway. In this study, we focused on the transient decrease in intracellular ATP concentration after radiation exposure and examined the protective effect of Hx against radiation-induced tissue damage. Human umbilical vein endothelial cells were X irradiated, and the cell viability and incidence of apoptosis and DNA double-strand breaks (DSBs) were evaluated at different Hx concentrations. We found that in the presence of 2-100 µM Hx, the percentages of DSBs and apoptotic cells after 2, 6 and 10 Gy dose of radiation significantly decreased, whereas cell viability increased in a concentration-dependent manner. Moreover, the addition of Hx increased the levels of AMP, ADP, and ATP in the cells at 2 h postirradiation, suggesting that Hx was used for adenine nucleotide synthesis through the salvage pathway. Administration of a xanthine oxidoreductase inhibitor to a mouse model of radiation dermatitis resulted in increased blood Hx levels that inhibited severe dermatitis and accelerated recovery. In conclusion, the findings provide evidence that increasing the levels of Hx to replenish ATP could be an effective strategy to reduce radiation-induced tissue damage and elucidating the detailed mechanisms underlying the protective effects of Hx could help develop new protective strategies against radiation.
Subject(s)
Dermatitis , Endothelial Cells , Adenosine Triphosphate , Animals , Cell Survival , Hypoxanthine/pharmacology , MiceABSTRACT
AIM: To investigate whether the type and frequency of social interaction during the state of emergency due to coronavirus disease were associated with self-rated health (SRH) after the state of emergency. METHODS: Data from a cross-sectional study were collected for 889 oldest-old adults in Bibai City, Hokkaido, Japan. In total, 612 participants (mean age: 83.0 ± 4.3 years; women: 51.8%) were included in the analysis, taking biological sex into account. The self-reported questionnaire included questions about demographic variables, SRH (July 2020, after the emergency), and the type and frequency of social interaction (March 2020, during the state of emergency). RESULTS: There was no significant association between social interaction and SRH in men (P > 0.05). Women who had social interactions (both face-to-face and non-face-to-face) more than once a week during the state of emergency reported higher SRH after the emergency than those who did not (odds ratio 2.17, 95% confidence interval 1.07-4.41). CONCLUSIONS: Having both types of interaction more than once a week during the state of emergency was related to higher SRH after the emergency among oldest-old women. It is suggested that having opportunities for both types of interaction at least once a week would potentially be beneficial for high SRH in women, even in situations where the declaration of a state of emergency restricts face-to-face interaction. Geriatr Gerontol Int 2022; 22: 405-411.
Subject(s)
COVID-19 , Independent Living , Aged , Aged, 80 and over , COVID-19/epidemiology , Cross-Sectional Studies , Female , Health Status , Humans , Japan/epidemiology , Male , Social InteractionABSTRACT
OBJECTIVES: The purpose of this cross-sectional study was to examine the association between cognitive frailty (CF) and higher-level competence among community-dwelling older adults. METHODS: Data from 871 older adults (aged ≥ 65 years, mean age 74.3 years, 61.5% women) who had participated in a community-based health check survey (Tarumizu Study 2018-2019) were analyzed. CF was defined as comorbid physical frailty and mild cognitive impairment (MCI). We defined physical frailty as either slow walking speed or poor grip strength. MCI was defined as values below the age- and education-adjusted reference threshold in several tests. Participants were categorized into four groups: robust, physical frailty, MCI, and CF. Higher-level competence was assessed using the Japan Science and Technology Agency Index of Competence (JST-IC). The JST-IC consists of 16 items and four subscales (technology usage, information practice, life management and social engagement). The bottom 20-30% score of the JST-IC and each subscale corresponded to poor higher-level competence. RESULTS: The prevalence of CF was 14.4%. Multivariate logistic regression analysis showed that, CF was significantly associated with poor higher-level competence (odds ratio 1.92, 95% confidence interval 1.18-3.13) after adjusting for covariates. Using a similar analysis to assess the JST-IC subscales, CF was associated with limitations on technology usage (odds ratio 2.29, 95% confidence interval 1.36-3.85) and low social engagement (odds ratio 1.62, 95% confidence interval 1.00-2.61). CONCLUSIONS: This study suggests that CF is associated with poor higher-level competence, especially limitations on technology usage and low social engagement.
Subject(s)
Cognitive Dysfunction , Frailty , Mental Competency , Aged , Cognitive Dysfunction/epidemiology , Cognitive Dysfunction/psychology , Cross-Sectional Studies , Female , Frail Elderly , Frailty/epidemiology , Geriatric Assessment , Humans , Independent Living , MaleSubject(s)
COVID-19 , Health Literacy , Adult , Cross-Sectional Studies , Exercise , Health Behavior , Humans , Middle Aged , Surveys and QuestionnairesABSTRACT
BACKGROUND: This cross-sectional study aimed to investigate the relationship of the ACTN3 genotype with thigh muscle volume and physical performance in older adults with sarcopenia or pre-sarcopenia. METHODS: Data from 64 older Japanese adults (mean age 74.4 ± 6.9 years, women 71.9%) with sarcopenia or pre-sarcopenia were analyzed. Sarcopenia and pre-sarcopenia were defined using the Asian Working Group for Sarcopenia. We collected oral mucosa samples to determine the ACTN3 genotype. Thigh muscle volumes were measured using magnetic resonance imaging. Physical performance was assessed using the usual and maximum gait speed, timed up and go test, and five-repetition sit-to-stand test. Muscle strength was assessed using grip strength. RESULT: The ACTN3 genotype proportions were 20.3% for RR, 51.6% for RX, and 28.1% for XX. Participants with the RR genotype showed greater thigh muscle volume/ht2 compared to those with the RX and XX ACTN3 genotypes (p < 0.05). The multiple linear regression analysis revealed that RX (p < 0.01) and XX (p < 0.01) ACTN3 genotypes, compared to RR, were associated with lower thigh muscle volume/ht2 and with age, sex (reference; men), weight and maximum walking speed. There was no significant difference between physical performance and muscle strength between the ACTN3 genotypes. CONCLUSION: The ACTN3 genotype of the X allele was associated with decreased thigh muscle volume compared to the ACTN3 genotype of RR in older adults with sarcopenia or pre-sarcopenia.
Subject(s)
Actinin , Sarcopenia , Actinin/genetics , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Genotype , Humans , Male , Muscle, Skeletal , Physical Functional Performance , Polymorphism, Genetic , Postural Balance , Sarcopenia/genetics , Thigh , Time and Motion StudiesABSTRACT
BACKGROUND: The effect of an unguided internet-based cognitive behavioral therapy (iCBT) stress management program on depression may be enhanced by applying artificial intelligence (AI) technologies to guide participants adopting the program. OBJECTIVE: The aim of this study is to describe a research protocol to investigate the effect of a newly developed iCBT stress management program adopting AI technologies on improving depression among healthy workers during the COVID-19 pandemic. METHODS: This study is a two-arm, parallel, randomized controlled trial. Participants (N=1400) will be recruited, and those who meet the inclusion criteria will be randomly allocated to the intervention or control (treatment as usual) group. A 6-week, six-module, internet-based stress management program, SMART-CBT, has been developed that includes machine-guided exercises to help participants acquire CBT skills, and it applies machine learning and deep learning technologies. The intervention group will participate in the program for 10 weeks. The primary outcome, depression, will be measured using the Beck Depression Inventory II at baseline and 3- and 6-month follow-ups. A mixed model repeated measures analysis will be used to test the intervention effect (group × time interactions) in the total sample (universal prevention) on an intention-to-treat basis. RESULTS: The study was at the stage of recruitment of participants at the time of submission. The data analysis related to the primary outcome will start in January 2022, and the results might be published in 2022 or 2023. CONCLUSIONS: This is the first study to investigate the effectiveness of a fully automated machine-guided iCBT program for improving subthreshold depression among workers using a randomized controlled trial design. The study will explore the potential of a machine-guided stress management program that can be disseminated online to a large number of workers with minimal cost in the post-COVID-19 era. TRIAL REGISTRATION: UMIN Clinical Trials Registryï¼UMIN-CTR) UMIN000043897; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000050125. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/30305.
ABSTRACT
OBJECTIVE: This study aimed to investigate associations between personal values and work engagement among workers. METHODS: This cross-sectional study used data from the Japanese Study on Stratification, Health, Income, and Neighborhood (J-SHINE) in 2010 and 2017. Personal values were measured by 11 value priorities and by commitment to these values. Multivariate linear regression analyses were conducted to determine the associations between personal values and work engagement. RESULTS: A total of 1946 workers were analyzed. Four personal values (eg, "Improving society") and commitment to values were significantly positively associated with work engagement, while "Graduating from a famous school" was significantly negatively associated. CONCLUSIONS: Some personal values relate to openness to change, self-transcendence, and self-enhancement, and commitment to values showed associations with work engagement. It could be beneficial to consider personal values to enhance work engagement.
Subject(s)
Income , Work Engagement , Cross-Sectional Studies , Humans , Linear Models , Multivariate AnalysisABSTRACT
OBJECTIVE: This study aimed to investigate the mediating effects of eudemonic well-being (EWB) at work for the associations between psychosocial work environment and overall EWB among Japanese workers. METHODS: We conducted a cross-sectional study using data from a 2018 survey. psychosocial work environment measures included: job demands, job control, and supervisor and coworker support. Path analysis using structural equation modeling and mediation analysis were applied to examine the mediating effects of work EWB. RESULTS: A total of 834 workers were analyzed. Work EWB completely mediated the associations of job control (ßâ=â0.288, Pâ<â0.001) and coworker support with overall EWB (ßâ=â0.178, Pâ<â0.001). CONCLUSIONS: The effects of job control and coworker support associated with overall EWB were fully mediated by work EWB.
Subject(s)
Job Satisfaction , Workplace , Cross-Sectional Studies , Humans , Japan , Social Support , Surveys and QuestionnairesSubject(s)
COVID-19 , Intersectoral Collaboration , Organizations , Pandemics , Public Health , Humans , JapanABSTRACT
Team job crafting, which refers to designing the task, relational, and cognitive aspects of a job, is thought to be beneficial for nurses working in the ward. There are no scales to assess team job crafting among nurses. This study aimed to develop and examine the reliability and validity of a scale to measure team job crafting. Based on literature reviews and interviews, potential items were created. A total of 293 nurses working on 19 wards in two hospitals in Japan were asked to complete a questionnaire twice. A series of exploratory factor analyses (EFAs) were conducted to select the final items. For convergent validity, multilevel correlations were calculated. Cronbach's α and intra-class correlation coefficients (ICCs) were calculated for reliability. A total of 190 participants responded to the baseline survey and 152 responded to the retest. The EFAs yielded a three-factor structure comprising 13 items. The three factors are task crafting considering the team's growth, cognitive crafting for members' respect and reflection of meaningfulness of work, and relational crafting for smooth information sharing. Cronbach's α ranged from .810 to .831, and test-retest ICCs ranged from 0.571 to 0.710. At the individual level, team job crafting had small-to-moderate correlations with individual levels of job crafting, job control, supervisor support, co-worker support, job satisfaction, workplace social capital, and work engagement. The ICC of the team job crafting scores of 0.125 indicated meaningful variation across wards. At the ward-level, nonsignificant but strong correlations were found with workplace social capital, job satisfaction, and psychological distress. This scale showed acceptable levels of reliability and validity. It would be useful in monitoring and improving team job crafting to increase team members' well-being and performance.
Subject(s)
Nursing Staff, Hospital , Patient Care Team , Psychometrics , Work Engagement , Adult , Female , Humans , Japan , Male , Middle Aged , Reproducibility of Results , Translations , Young AdultABSTRACT
The use of in vitro systems that allow efficient selection of probiotic candidates with immunomodulatory properties could significantly minimize the use of experimental animals. In this work, we generated an in vitro immunoassay system based on porcine intestinal epithelial (PIE) cells and dextran sodium sulfate (DSS) administration that could be useful for the selection and characterization of potential probiotic strains to be used in inflammatory bowel disease (IBD) patients. Our strategy was based on two fundamental pillars: on the one hand, the capacity of PIE cells to create a monolayer by attaching to neighboring cells and efficiently mount inflammatory responses and, on the other hand, the use of two probiotic bifidobacteria strains that have been characterized in terms of their immunomodulatory capacities, particularly in mouse IBD models and patients. Our results demonstrated that DSS administration can alter the epithelial barrier created in vitro by PIE cells and induce a potent inflammatory response, characterized by increases in the expression levels of several inflammatory factors including TNF-α, IL-1α, CCL4, CCL8, CCL11, CXCL5, CXCL9, CXCL10, SELL, SELE, EPCAM, VCAM, NCF2, and SAA2. In addition, we demonstrated that Bifidobacterium breve M-16V and B. longum BB536 are able to regulate the C-jun N-terminal kinase (JNK) intracellular signalling pathway, reducing the DSS-induced alterations of the in vitro epithelial barrier and differentially regulating the inflammatory response in a strain-dependent fashion. The good correlation between our in vitro findings in PIE cells and previous studies in animal models and IBD patients shows the potential value of our system to select new probiotic candidates in an efficient way.
Subject(s)
Bifidobacterium , Epithelial Cells/microbiology , Immunoassay , Inflammatory Bowel Diseases , Probiotics , Animals , Chemokines , Cytokines , Humans , Inflammatory Bowel Diseases/therapy , Mice , SwineABSTRACT
Immunobiotics have emerged as a promising intervention to alleviate intestinal damage in inflammatory bowel disease (IBD). However, the beneficial properties of immunobiotics are strain dependent and, therefore, each strain has to be evaluated in order to demonstrate its potential application in IBD. Our previous in vitro and in vivo studies demonstrated that Lactobacillus jensenii TL2937 attenuates gut acute inflammatory response triggered by Toll-like receptor 4 activation. However, its effect on colitis has not been evaluated before. In this work, we studied whether the TL2937 strain was able to protect against the development of colitis in a dextran sodium sulfate (DSS)-induced mouse model and we delved into the mechanisms of action by evaluating the effect of the immunobiotic bacteria on the transcriptomic response of DSS-challenged intestinal epithelial cells. L. jensenii TL2937 was administered to adult BALB/c mice before the induction of colitis by the administration of DSS. Colitis and the associated inflammatory response were evaluated for 14 days. Mice fed with L. jensenii TL2937 had lower disease activity index and alterations of colon length when compared to control mice. Reduced myeloperoxidase activity, lower production of pro-inflammatory (TNF-α, IL-1, CXCL1, MCP-1, IL-15, and IL-17), and higher levels of immunoregulatory (IL-10 and IL-27) cytokines were found in the colon of TL2937-treated mice. In addition, the treatment of porcine intestinal epithelial (PIE) cells with L. jensenii TL2937 before the challenge with DSS differentially regulated the activation of the JNK pathway, leading to an increase in epithelial cell integrity and to a differential immunotranscriptomic response. TL2937-treated PIE cells had a significant reduction in the expression of inflammatory cytokines (TNF-α, IL-1α, IL-1ß, IL-6, IL-15), chemokines (CCL2, CCL4, CCL8, CXCL4, CXCL5, CXCL9, CXCL10), adhesion molecules (SELE, SELL, EPCAM), and other immune factors (NCF1, NCF2, NOS2, SAA2) when compared to control cells after the challenge with DSS. The findings of this work indicate that (a) L. jensenii TL2937 is able to alleviate DSS-induced colitis suggesting a potential novel application for this immunobiotic strain, (b) the modulation of the transcriptomic response of intestinal epithelial cells would play a key role in the beneficial effects of the TL2937 strain on colitis, and (c) the in vitro PIE cell immunoassay system could be of value for the screening and selection of new immunobiotic strains for their application in IBD.
Subject(s)
Colitis/therapy , Intestinal Mucosa/pathology , Lactobacillus/physiology , Animals , Chemokines/genetics , Chemokines/metabolism , Colitis/chemically induced , Colitis/microbiology , Cytokines/genetics , Cytokines/metabolism , Dextran Sulfate , Disease Models, Animal , Female , Gene Expression Profiling , Humans , Inflammation Mediators/metabolism , Mice , Mice, Inbred BALB C , ProbioticsABSTRACT
This study aimed to assess the effects of a multicomponent exercise program on physical function and muscle mass in older adults with sarcopenia or pre-sarcopenia. Moreover, we aim to standardize the exercise program for easy incorporation in the daily life of community-dwelling older adults as a secondary outcome. A single-blind randomized controlled trial was conducted with individuals (≥60 years) who had sarcopenia or pre-sarcopenia (n = 72). Participants were randomly assigned to the exercise and control groups. The exercise program consisted of 12 weekly 60-minute sessions that included resistance, balance, flexibility, and aerobic training. Outcome measures were physical function and muscle mass. Assessments were conducted before and immediately after the intervention. Among the 72 participants (mean age: 75.0 ± 6.9 years; 70.8% women), 67 (93.1%) completed the trial. Group-by-time interactions on the chair stand (p = 0.02) and timed "up and go" (p = 0.01) tests increased significantly in the exercise group. Although the exercise group showed a tendency to prevent loss of muscle mass, no significant interaction effects were observed for cross-sectional muscle area and muscle volume. The 12-week exercise program improved physical function in the intervention group. Although it is unclear whether the program is effective in increasing muscle mass, a multicomponent exercise program would be an effective treatment for physical function among older adults with sarcopenia.
ABSTRACT
Renal hypouricemia sometimes leads to exercise-induced acute kidney injury (EIAKI) of unknown pathogenesis. In order to elucidate the various pathological conditions associated with hypouricemia, we analyzed the effects of low uric acid level on energy metabolism. We have modified semi-ischemic forearm exercise test and performed this test in one Japanese healthy volunteer, three patients with hereditary renal hypouricemia and one patient with hereditary xanthinuria of Czech origin. Forearm exercise was performed by squeezing a hand dynamometer with the sphygmomanometer cuff pressure kept at the mean arterial pressure. Venous blood was drawn five times (before exercise, 3, 10, 30, 45 minutes after the start of exercise) in each tests. The mean plasma lactate concentration increased from a baseline of 1.3 (range 0.7-1.8 mmol/L) to 4.0 (range 2.0-5.5 mmol/L) at 3 minutes after the start of exercise. The plasma hypoxanthine concentrations were quite low before exercise (0-2.9 µmol/L), but increased markedly to a range of 13.6-28.8 µmol/L after 10 minute forearm ischemia. Our protocol allowed us to conclude that the load was sufficient for observing metabolic changes in temporally hypoxia and in following recovery phase. The test was well tolerated and safe, we did not observe any adverse reactions including EIAKI.