Exploring fluoropolymers for fabrication of femtoliter chamber arrays used in digital bioanalysis.

The global supply of fluoropolymers and fluorinated solvents is decreasing due to environmental concerns regarding polyfluoroalkyl substances. CYTOP has been used for decades primarily as a component of a femtoliter chamber array for digital bioanalysis; however, its supply has recently become scarce, increasing the urgency of fabricating a femtoliter chamber array using alternative materials. In this study, we investigated the feasibility of fabricating a femtoliter chamber array using four types of fluoropolymers in stable supply as candidate substitutes and verified their applicability for digital bioanalysis. Among these candidates, Fluorine Sealant emerged as a viable option for fabricating femtoliter chamber arrays using a conventional photolithography process. To validate its efficacy, we performed various digital bioanalysis using FP-A-based chamber arrays with model enzymes such as CRISPR-Cas, horseradish peroxidase, and ß-galactosidase. The results demonstrated the similar performance to that of CYTOP, highlighting the broader utility of FP-A in digital bioanalysis. Our findings underscore the potential of FP-A to enhance the versatility of digital bioanalysis and foster the ongoing advancement of innovative diagnostic technologies.

Body Roundness Index Is Better Correlated with Insulin Sensitivity than Body Shape Index in Young and Middle-Aged Japanese Persons.

Aims: The present study aimed to clarify the relationships between novel and traditional anthropometric indices and insulin sensitivity (SI) in young and middle-aged Japanese persons with normal glucose tolerance (NGT), and middle-aged Japanese persons with NGT and glucose intolerance. Methods: Plasma glucose and insulin levels were measured in 1270 young (age <40 years) and 2153 middle-aged persons with NGT (n = 1531) and glucose intolerance (n = 622) during a 75-g oral glucose tolerance test. Height (Ht), weight, and waist circumference (WC) were measured. The body mass index (BMI), WC, and the WC/Ht ratio were used as traditional anthropometric indices. A body shape index (ABSI) and the body roundness index (BRI) were calculated as novel indices. Indices of SI (Matsuda index and 1/homeostasis model assessment of insulin resistance) were calculated and compared with anthropometric indices. Results: The ABSI showed a weak correlation with SI indices in all groups. The BRI showed almost the same correlation with SI indices as the BMI, WC, and WC/Ht in all groups. The inverse correlation between each of the anthropometric indices other than ABSI and SI indices was weak in young persons, at 0.16-0.27 (Spearman's ρ values), but strong in middle-aged persons, at 0.38-1.00. On receiver-operating characteristic (ROC) curve analysis for detection of insulin resistance, the ABSI had a lower area under the ROC curve (AUC) than the other anthropometric indices, and the BRI and the WC/Ht ratio showed similar AUCs. The AUCs for the BRI and WC/Ht ratio were the highest in middle-aged men with NGT and glucose intolerance. Conclusions: The BRI, not the ABSI, was better correlated with SI in young and middle-aged Japanese persons. The BRI and WC/Ht ratio were comparable in their correlations with SI and the detection of insulin resistance in the participants of the present study.

A Pharmacovigilance Study of Drug-Induced Glaucoma Utilizing the Japanese Adverse Event Reporting System.

Purpose: Clinically, glaucoma is a serious problem because it is asymptomatic until a relatively late stage in most cases, which can lead to delays in the diagnosis and treatment of the disease. The purpose of this study was to clarify the rank-order of the association of glaucoma with the causative drugs using a spontaneous reporting system database. Methods: Data were extracted from the Japanese Adverse Drug Event Report database of the Pharmaceuticals and Medical Devices Agency (Japan). Based on reports of glaucoma caused by all drugs, we calculated the reporting odds ratio (ROR) and 95% confidence interval (CI) for glaucoma. Results: Among 609 reports of adverse events corresponding to glaucoma (46%, women), the most frequently implicated drug were steroids (prednisolone, betamethasone sodium phosphate, triamcinolone acetonide, and fluorometholone), pregabalin, ranibizumab, crizotinib, tacrolimus hydrate, darbepoetin alfa, and foscarnet sodium hydrate. Among 207 reports involved in angle-closure glaucoma (86%, women), anticholinergic drug and antidepressants ranked high and showed signals. Signals were also detected in bromazepam (ROR, 69.7; 95% CI, 30.9-157.5), oral brotizolam (ROR, 16.6; 95% CI, 6.18-44.8), and oral milnacipran hydrochloride (ROR, 22.8; 95% CI, 8.46-61.4) for angle-closure glaucoma. Conclusion: A national pharmacovigilance database enabled us to identify the drugs that frequently induce glaucoma. The likelihood of the reporting of glaucoma varied among the drugs, which should be used carefully in clinical practice to avoid it.

SATORI: Amplification-free digital RNA detection method for the diagnosis of viral infections.

With the recent global outbreak of COVID-19, there is an urgent need to establish a versatile diagnostic method for viral infections. Gene amplification test or antigen test are widely used to diagnose viral infections; however, these methods generally have technical drawbacks either in terms of sensitivity, accuracy, or throughput. To address this issue, we recently developed an amplification-free digital RNA detection method (SATORI), which can identify and detect viral genes at the single-molecule level in approximately 9 min, satisfying almost all detection performance requirements for the diagnosis of viral infections. In addition, we also developed practical platforms for SATORI, such as an automated platform (opn-SATORI) and a low-cost compact fluorescence imaging system (COWFISH), with the aim of application in clinical settings. Our latest technologies can be inherently applied to diagnose a variety of RNA viral infections, such as COVID-19 and Influenza A/B, and therefore, we expect that SATORI will be established as a versatile platform for point-of-care testing of a wide range of infectious diseases, thus contributing to the prevention of future epidemics. This article is an extended version of the Japanese article published in the SEIBUTSU BUTSURI Vol. 63, p. 115-118 (2023).

Design of allosteric sites into rotary motor V1-ATPase by restoring lost function of pseudo-active sites.

Allostery produces concerted functions of protein complexes by orchestrating the cooperative work between the constituent subunits. Here we describe an approach to create artificial allosteric sites in protein complexes. Certain protein complexes contain subunits with pseudo-active sites, which are believed to have lost functions during evolution. Our hypothesis is that allosteric sites in such protein complexes can be created by restoring the lost functions of pseudo-active sites. We used computational design to restore the lost ATP-binding ability of the pseudo-active site in the B subunit of a rotary molecular motor, V1-ATPase. Single-molecule experiments with X-ray crystallography analyses revealed that binding of ATP to the designed allosteric site boosts this V1's activity compared with the wild-type, and the rotation rate can be tuned by modulating ATP's binding affinity. Pseudo-active sites are widespread in nature, and our approach shows promise as a means of programming allosteric control over concerted functions of protein complexes.

Purification/Amplification-Free RNA Detection Platform for Rapid and Multiplex Diagnosis of Plant Viral Infections.

Genetic tests are highly sensitive, and quantitative methods for diagnosing human viral infections, including COVID-19, are also being used to diagnose plant diseases in various agricultural settings. Conventional genetic tests for plant viruses are mostly based on methods that require purification and amplification of viral genomes from plant samples, which generally take several hours in total, making it difficult to use them in rapid detection at point-of-care testing (POCT). In this study, we developed Direct-SATORI, a rapid and robust genetic test that eliminates the purification and amplification processes of viral genomes by extending the recently developed amplification-free digital RNA detection platform called SATORI, allowing the detection of various plant viral genes in a total of less than 15 min with a limit of detection (LoD) of 98 ∼ copies/µL using tomato viruses as an example. In addition, the platform can simultaneously detect eight plant viruses directly from ∼1 mg of tomato leaves with a sensitivity of 96% and a specificity of 99%. Direct-SATORI can be applied to various infections related to RNA viruses, and its practical use is highly anticipated as a versatile platform for plant disease diagnostics in the future.

Compact wide-field femtoliter-chamber imaging system for high-speed and accurate digital bioanalysis.

The femtoliter-chamber array is a bioanalytical platform that enables highly sensitive and quantitative analysis of biological reactions at the single-molecule level. This feature has been considered a key technology for "digital bioanalysis" in the biomedical field; however, its versatility is limited by the need for a large and expensive setup such as a fluorescence microscope, which requires a long time to acquire the entire image of a femtoliter-chamber array. To address these issues, we developed a compact and inexpensive wide-field imaging system (COWFISH) that can acquire fluorescence images with a large field of view (11.8 mm × 7.9 mm) and a high spatial resolution of ∼ 3 µm, enabling high-speed analysis of sub-million femtoliter chambers in 20 s. Using COWFISH, we demonstrated a CRISPR-Cas13a-based digital detection of viral RNA of SARS-CoV-2 with an equivalent detection sensitivity (limit of detection: 480 aM) and a 10-fold reduction in total imaging time, as compared to confocal fluorescence microscopy. In addition, we demonstrated the feasibility of COWFISH to discriminate between SARS-CoV-2-positive and -negative clinical specimens with 95% accuracy, showing its application in COVID-19 diagnosis. Therefore, COWFISH can serve as a compact and inexpensive imaging system for high-speed and accurate digital bioanalysis, paving a way for various biomedical applications, such as diagnosis of viral infections.

Clinical characteristics and efficacy of pioglitazone in a Japanese patient with familial partial lipodystrophy due to peroxisome proliferator-activated receptor γ gene mutation.

Familial partial lipodystrophy (FPLD) 3 is a rare genetic disorder caused by peroxisome proliferator-activated receptor γ gene (PPARG) mutations. Most cases have been reported in Western patients. Here, we describe a first pedigree of FPLD 3 in Japanese. The proband was a 51-year-old woman. She was diagnosed with fatty liver at age 32 years, dyslipidemia at age 37 years, and diabetes mellitus at age 41 years. Her body mass index was 18.5 kg/m2, and body fat percentage was 19.2%. On physical examination, she had less subcutaneous fat in the upper limbs than in other sites. On magnetic resonance imaging, atrophy of subcutaneous adipose tissue was seen in the upper limbs and lower legs. Fasting serum C-peptide immunoreactivity was high (3.4 ng/mL), and the plasma glucose disappearance rate was low (2.07%/min) on an insulin tolerance test, both suggesting apparent insulin resistance. The serum total adiponectin level was low (2.3 µg/mL). Mild fatty liver was seen on abdominal computed tomography. On genetic analysis, a P495L mutation in PPARG was identified. The same mutation was also seen in her father, who had non-obese diabetes mellitus, and FPLD 3 was diagnosed. Modest increases in body fat and serum total adiponectin were seen with pioglitazone treatment. Attention should be paid to avoid overlooking lipodystrophy syndromes even in non-obese diabetic patients if they show features of insulin resistance.

Direct observation of stepping rotation of V-ATPase reveals rigid component in coupling between Vo and V1 motors.

V-ATPases are rotary motor proteins that convert the chemical energy of ATP into the electrochemical potential of ions across cell membranes. V-ATPases consist of two rotary motors, Vo and V1, and Enterococcus hirae V-ATPase (EhVoV1) actively transports Na+ in Vo (EhVo) by using torque generated by ATP hydrolysis in V1 (EhV1). Here, we observed ATP-driven stepping rotation of detergent-solubilized EhVoV1 wild-type, aE634A, and BR350K mutants under various Na+ and ATP concentrations ([Na+] and [ATP], respectively) by using a 40-nm gold nanoparticle as a low-load probe. When [Na+] was low and [ATP] was high, under the condition that only Na+ binding to EhVo is rate limiting, wild-type and aE634A exhibited 10 pausing positions reflecting 10-fold symmetry of the EhVo rotor and almost no backward steps. Duration time before the forward steps was inversely proportional to [Na+], confirming that Na+ binding triggers the steps. When both [ATP] and [Na+] were low, under the condition that both Na+ and ATP bindings are rate limiting, aE634A exhibited 13 pausing positions reflecting 10- and 3-fold symmetries of EhVo and EhV1, respectively. The distribution of duration time before the forward step was fitted well by the sum of two exponential decay functions with distinct time constants. Furthermore, occasional backward steps smaller than 36° were observed. Small backward steps were also observed during three long ATP cleavage pauses of BR350K. These results indicate that EhVo and EhV1 do not share pausing positions, Na+ and ATP bindings occur at different angles, and the coupling between EhVo and EhV1 has a rigid component.

Current Status of Adverse Event Profile of Cyclosporine in Kidney, Stem Cell, and Heart Transplantations Using the Japanese Pharmacovigilance Database.

BACKGROUND: Cyclosporine is widely used to prevent allograft rejection after transplantation. The purpose of this study was to clarify the adverse events profiles associated with cyclosporine in transplant patients using a spontaneous reporting system database. METHODS: Retrospective pharmacovigilance disproportionality analysis was conducted using the Japanese Adverse Drug Event Report (JADER) database, with the reporting odds ratio (ROR) and 95% confidence interval (CI) for each adverse event. RESULTS: The database comprised 3,327, 958, and 956 reports associated with cyclosporine in the kidney, stem cell, and heart transplant patients, respectively. Infectious and renal disorders were commonly detected in these transplant patients. The signal scores of cyclosporine for toxic nephropathy were noteworthy in the kidney (ROR: 15.1, 95% CI: 11-20.8) and stem cell (ROR, 216; 95% CI, 29.3-1593) transplantation. Cyclosporine in heart transplantation was strongly associated with gastric cancer (ROR, 39.4; 95% CI, 16.7-93.2), but not kidney or stem cell transplantation. CONCLUSION: It was suggested that there is a diversity in the strength of the association between cyclosporine and adverse events in the kidney, stem cell, and heart transplantation. Our results may provide useful information for treatment with cyclosporine, although further research with more data is needed.

Adverse event profiles of drugs used for treatment of juvenile idiopathic arthritis according to spontaneous reporting system database.

Juvenile idiopathic arthritis (JIA) is a systemic inflammatory disease of childhood onset. The purpose of this study was to clarify the frequency of adverse events caused by drugs used in JIA treatment and characterize their safety profiles using a spontaneous reporting system database. We performed a retrospective pharmacovigilance disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database. Adverse event reports on drugs used for the treatment of JIA and which were submitted to the Pharmaceuticals and Medical Devices Agency were analyzed, and the reporting odds ratio (ROR) and 95% confidence interval (CI) for reports on each adverse event were calculated. A total of 5,748 reports were identified in the treatment of JIA, in which 35 different drugs were involved. Adverse events by drugs in JIA were frequently reported in females (64.3%) and in those younger than 10 (61.2%). Among the most frequently reported drugs, prednisolone (36.8%) and tocilizumab (36.0%) were predominant. Prednisolone was significantly correlated with hematophagic histiocytosis (ROR, 1.37; 95% CI, 1.18 - 1.61). Tocilizumab was associated with a high ROR for pneumonia (ROR, 8.61: 95% CI, 5.81 - 12.7), a decreased neutrophil count (ROR, 6.1; 95% CI, 4.07 - 9.16), and lymphadenitis (ROR, 8.34; 95% CI, 4.2 - 16.6). Our results revealed the safety profile of drugs for the treatment of JIA patients. It was suggested that there is a diversity in drugs and their strength of association with adverse events in JIA patients. Our results may provide useful information for the treatment of JIA patients, although further research with more data is needed.

Diabetic family history in young Japanese persons with normal glucose tolerance associates with k-means clustering of glucose response to oral glucose load, insulinogenic index and Matsuda index.

Aims: The present study aimed to clarify the relationships between diabetic family history (FH), and dysglycemic response to the oral glucose tolerance test (OGTT), insulin secretion, and insulin sensitivity in young Japanese persons with normal glucose tolerance (NGT). Methods: We measured plasma glucose (PG) and immunoreactive insulin levels in 1,309 young Japanese persons (age <40 years) with NGT before and at 30, 60, and 120 min during a 75-g OGTT. Dysglycemia during OGTT was analyzed by k-means clustering analysis. Body mass index (BMI), blood pressure (BP), and lipids were measured. Insulin secretion and sensitivity indices were calculated. Results: PG levels during OGTT were classified by k-means clustering analysis into three groups with stepwise decreases in glucose tolerance even among individuals with NGT. In these clusters, proportion of males, BMI, BP and frequency of FH were higher, and lipid levels were worse, together with decreasing glucose tolerance. Subjects with a diabetic FH showed increases in PG after glucose loading and decreases in insulinogenic index and Matsuda index. Conclusions: Dysglycemic response to OGTT by k-means clustering analysis was associated with FH in young Japanese persons with NGT. FH was also associated with post-loading glucose, insulinogenic index, and Matsuda index.

Automated amplification-free digital RNA detection platform for rapid and sensitive SARS-CoV-2 diagnosis.

In the ongoing COVID-19 pandemic, rapid and sensitive diagnosis of viral infection is a critical deterrent to the spread of SARS-CoV-2. To this end, we developed an automated amplification-free digital RNA detection platform using CRISPR-Cas13a and microchamber device (opn-SATORI), which automatically completes a detection process from sample mixing to RNA quantification in clinical specimens within ~9 min. Using the optimal Cas13a enzyme and magnetic beads technology, opn-SATORI detected SARS-CoV-2 genomic RNA with a LoD of < 6.5 aM (3.9 copies µL-1), comparable to RT-qPCR. Additionally, opn-SATORI discriminated between SARS-CoV-2 variants of concern, including alpha, delta, and omicron, with 98% accuracy. Thus, opn-SATORI can serve as a rapid and convenient diagnostic platform for identifying several types of viral infections.

Association between sarcopenia and the severity of diabetic polyneuropathy assessed by nerve conduction studies in Japanese patients with type 2 diabetes mellitus.

AIMS/INTRODUCTION: This study examined the association between the severity of diabetic polyneuropathy (DPN) based on the Baba classification, and sarcopenia and its related factors. MATERIALS AND METHODS: The participants were 261 patients with type 2 diabetes mellitus. DPN was classified as stages 0-4 according to the Baba classification. Sarcopenia was diagnosed based on measurements of the skeletal mass index, grip strength and walking speed, using the Asia Working Group for Sarcopenia 2019 diagnostic criteria. RESULTS: The median age of the participants was 67 years, the proportion of men was 58.6%, the median estimated duration of diabetes was 10 years and the median values for glycated hemoglobin were 10.3%. With regard to DPN, the prevalence of Baba classification stages 0-2 was 90.8% (n = 237), and that of stage 3 or 4 was 9.2% (n = 24). The prevalence of sarcopenia was 19.9%. A trend toward an increase in the frequency of slow walking speed was seen as the stage of DPN progressed. The frequencies of sarcopenia and slow walking speed were higher in the group with the Baba classification stages 3 and 4 than in the group with stages 0-2. On multiple logistic regression analyses, however, DPN was not significantly related to sarcopenia and walking speed. CONCLUSIONS: Although severe DPN might be related to sarcopenia, the frequency of severe DPN is low in the clinical setting, indicating that its contribution to sarcopenia is modest.

Secondary Hypogonadism due to Excessive Ingestion of Isoflavone in a Man.

A 54-year-old man had been drinking approximately 1.2 L of soy milk (equivalent to approximately 310 mg of isoflavones) per day for the previous 3 years. He then developed erectile dysfunction and gynecomastia. On an examination in our department in May, blood tests showed low gonadotropin and testosterone levels, indicative of secondary hypogonadism. He stopped drinking soy milk on his own in June of that year. When he was admitted in August, blood tests showed an improved gonadal function. Secondary hypogonadism caused by the excessive intake of isoflavones in soy milk was diagnosed. In men, an excessive intake of isoflavones may cause feminization and secondary hypogonadism.

Drug-induced Neuropsychiatric Adverse Events Using Post-Marketing Surveillance.

BACKGROUND: Several studies reported that abnormal behavior was noted in pediatric patients receiving several drugs, including neuraminidase inhibitors (NIs). However, the information on drugs associated with abnormal behavior in a real-world setting remains limited. The purpose of this study was to clarify the drugs associated with abnormal behavior using a spontaneous reporting system database. METHODS: We performed a retrospective pharmacovigilance disproportionality analysis using the Japanese Adverse Drug Event Report database. Adverse event reports submitted to the Pharmaceuticals and Medical Devices Agency were analyzed, and the reporting odds ratio at 95% confidence interval were calculated. RESULTS: A total of 1,144 reports of abnormal behavior were identified. The signals were detected through the association of 4 neuraminidase inhibitors (oseltamivir, zanamivir, laninamivir, and peramivir) with the abnormal behaviour. These signals were stronger for oseltamivir than other neuraminidase inhibitors. The signals were also detected for acetaminophen and montelukast. CONCLUSION: Our results should be able to raise physicians' awareness of drugs associated with abnormal behavior, but further investigation of these medications is warranted.

Postloading insulinemia is independently associated with arterial stiffness in young Japanese persons.

Associations of arterial stiffness with glucose, insulin, and proinsulin dynamics during the oral glucose tolerance test (OGTT) remain under debate. The aim of this study was to investigate whether plasma glucose (PG), insulin, and proinsulin (Pro) contribute to arterial stiffness, measured by pulse wave velocity (PWV), in young Japanese persons. PG, immunoreactive insulin (IRI), and Pro levels were determined in 1193 young Japanese subjects (<40 years of age) with normal glucose tolerance or nondiabetic hyperglycemia before and at 30, 60, and 120 min during a 75-g OGTT. Participants were divided into two groups according to the median PWV. Background factors, PG, IRI, and Pro levels during the OGTT, and insulin sensitivity (SI) indices in each group were compared. Several multiple regression analysis models were used to evaluate factors contributing to PWV. All IRI and Pro levels before and after glucose loading and the area under the curve (AUC) values for IRI and Pro increased with higher PWV. 1/HOMA-IR and ISI-Matsuda as measures of SI decreased with higher PWV. The IRI AUC and Pro level before glucose loading (Pro0) were independently associated with PWV, in addition to male sex, heart rate, and mean blood pressure. The IRI AUC had a stronger relationship with PWV than Pro0. The IRI AUC had an independent relationship with PWV, whereas both SI indices did not. Postloading insulinemia, but not reduced SI, was independently associated with arterial stiffness in young Japanese persons.

Glucose Effectiveness Decreases in Relationship to a Subtle Worsening of Metabolic Parameters in Young Japanese with Normal Glucose Tolerance.

Background: The aim of the study was to investigate the relationship between glucose effectiveness (Sg) and some metabolic parameters in male and female young Japanese. Methods: We measured plasma glucose and immunoreactive insulin levels in 1309 young Japanese persons (age <40 years) with normal glucose tolerance (NGT) before and at 30, 60, and 120 min during a 75 gram oral glucose tolerance test. We also measured serum adiponectin and high-sensitivity C-reactive protein (hsCRP) levels and oral glucose effectiveness (SgIO), and investigated factors related to SgIO. Results: The results of Spearman correlation analysis revealed that high-density lipoprotein cholesterol (HDL) and adiponectin were positively correlated with SgIO, whereas the proportion of males, body mass index, waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure, triglycerides (TG), and hsCRP were inversely correlated with SgIO. The results of multiple regression analysis indicated negative correlations between SgIO and the proportion of males, WC, and SBP and a positive correlation with HDL. The results of multiple regression analysis excluding WC indicated negative correlations between SgIO and the proportion of males, SBP, and TG and positive correlations with HDL and adiponectin. Conclusions: Sg decreased with a subtle worsening of metabolic parameters, even in young persons with NGT. Decreased Sg may be involved in the development of glucose intolerance in individuals with worse metabolic parameters.

Association between a low dose of proton pump inhibitors and kidney function decline in elderly hypertensive patients: a retrospective observational study.

OBJECTIVES: Proton pump inhibitors (PPIs) are widely used for acid suppression therapy. Recently, PPI use was reported to be associated with chronic kidney disease (CKD); however, whether a low dose of PPIs is associated with CKD remains unknown. METHODS: This retrospective observational study included hypertensive patients who visited Kenwakai Hospital between 2017 and 2019. Renal parameters, such as the estimated glomerular filtration rate (eGFR) and serum creatinine (Scr), were extracted from medical records and compared between three years before treatment and the baseline. PPI use was assessed as cumulative exposure for three years. RESULTS: The study population included 152 patients (57.9% men; mean age, 74.5 years). Of those, 35.5% were PPI users (low dose, 17.1%; high dose, 18.4%). A significant decrease in eGFR and an increase in Scr were observed between three years before treatment and the baseline in the high-dose PPI group but not the non-use or low-dose PPI groups. CONCLUSIONS: Our results suggest that a low dose of PPIs may be safe in clinical settings, but further prospective studies are needed to clarify our findings.

Analysis of the Relationships between Multiple Endocrine Hormones and Return of Spontaneous Circulation (ROSC) in Cardiac Arrest Patients: Possible Association of the Serum Free T4 Level with ROSC.

BACKGROUND: Endocrine hormones are closely associated with homeostasis, so it is important to clarify hormone secretion dynamics in shock. Few reports, however, have examined the dynamics of endogenous hormone secretion relative to prognosis in cardiac arrest patients. Therefore, to clarify the roles of endocrine hormones in out-of-hospital cardiac arrest (OHCA) patients, the concentrations of anterior pituitary, thyroid, and adrenocortical hormones were measured, and their associations with return of spontaneous circulation (ROSC) were examined. METHODS: The subjects were OHCA patients transported to our Emergency Department. In addition to conventional clinical laboratory tests, the following were measured: serum TSH, serum free T3, serum free T4 (F-T4), plasma ACTH, serum cortisol, serum GH, serum IGF-1, plasma aldosterone concentration (PAC), and plasma renin activity. The primary endpoint was the presence or absence of ROSC, and the secondary endpoint was 24-hour survival. RESULTS: A total of 29 patients, 17 in the ROSC group and 12 in the non-ROSC group, were studied. There were associations between ROSC and low serum potassium, high F-T4, low cortisol, and low PAC on bivariate analyses. There were associations between ROSC and serum potassium, F-T4, and GH using the step-wise method. On multiple logistic regression analysis, a relationship between ROSC and high serum F-T4 level was identified by both methods. There were also associations between 24-hour survival and both low serum potassium and elevated blood glucose levels. CONCLUSIONS: The present findings suggest a possible relationship between the serum F-T4 level and ROSC in OHCA patients. A higher serum F-T4 level might cause an increase in the ß-adrenergic response in cardiomyocytes and increased responsiveness to catecholamines and was possibly associated with ROSC.