Exploratory Feasibility Study of Cerebral Cooling by Transpulmonary Cooling During Cardiac Arrest in a Swine Cardiac Arrest Model.

Studies on targeted temperature management for postcardiac arrest syndrome have shown no difference in outcomes between normothermia and hypothermia in patients with postcardiac arrest brain injury. Therefore, further development of therapeutic methods for temperature control in cardiac arrest patients is desirable. Although animal studies have shown that inducing hypothermia during cardiac arrest improves outcomes, no clinically effective method has yet been reported. We investigated whether intra-arrest lung cooling (IALC) effectively lowers brain temperature. A device capable of cooling oxygen was developed. The pigs were subjected to cardiac arrest using the device, ventilated, cooled during cardiopulmonary resuscitation, and resuscitated for 1 hour, with changes in brain temperature closely monitored. A device capable of cooling oxygen to -30°C was used to cool the lungs during cardiac arrest. Through this approach, IALC successfully reduced the brain temperature. Optimal cooling efficiency was observed when chest compressions and ventilation were synchronized at a ratio of 5:1, resulting in an approximate brain temperature reduction of 1.5°C/h. Our successful development of an oxygen-cooling device underscores the potential for lowering brain temperature through IALC using inhaled oxygen cooling.

Continuous renal replacement therapy with vitamin E-coated polysulfone hemofilter reduces inflammatory responses in a porcine lipopolysaccharide-treated model.

INTRODUCTION: Biological invasions may promote the onset of systemic inflammatory response syndrome in patients eligible for continuous renal replacement therapy (CRRT), leading to poor prognosis. Hence, we aimed to examine the inflammatory reactions in circulation using vitamin E-coated polysulfone hollow fiber membrane (ViLIFE). METHODS: Lipopolysaccharides were intravenously administered to pigs (2 µg/kg/30 min) to establish an acute inflammation model. Extracorporeal circulation was performed for 6 h in continuous venovenous hemodiafiltration mode using a hemofilter for CRRT filled with a polysulfone hollow fiber membrane or ViLIFE, and the differences in inflammatory reactions were evaluated. RESULTS: The ViLIFE group exhibited low platelet and cytokine levels (p < 0.05 vs. sham-CRRT group). Additionally, the ViLIFE group had lower lactate and high mobility group box 1 levels than the other groups. CONCLUSION: ViLIFE represents a promising CRRT modality that can inhibit the inflammatory response in circulation and inhibit further biological invasions.

Levels and spatial profile of per- and polyfluoroalkyl substances in edible shrimp products from Japan and neighboring countries; a potential source of dietary exposure to humans.

Exposure to per- and polyfluoroalkyl substances (PFAS) is of great concern for human health because of their persistence and potentially adverse effects. Dietary intake, particularly through aquatic products, is a significant route of human exposure to PFAS. We analyzed perfluoroalkyl sulfonic acid (PFSA with carbon numbers from 6 to 8 and 10 (C６-C8, C10)) and perfluorooctanesulfonamide (FOSA), and perfluoroalkyl carboxylic acid (PFCA with carbon numbers from 6 to 15 (C6-C15)) in 30 retail packs of edible shrimps, which included seven species from eight coastal areas of Japan and neighboring countries. The most prevalent compounds were perfluorooctane sulfonate (PFOS, C8) and perfluoroundecanoic acid (PFUnDA, C11), accounting for 46 % of total PFAS. The concentrations ranged from 6.5 to 44 ng/g dry weight (dw) (equivalent to 1.5 to 10 ng/g wet weight (ww)) and varied according to species and location. For example, Alaskan pink shrimp (Pandalus eous) from the Hokuriku coast, Japan contained high levels of long-chain PFCAs (38 ng/g dw (equivalent to 8.7 ng/g ww)), while red rice prawn (Metapenaeopsis barbata) from Yamaguchi, Japan contained a high concentration of PFOS (29 ng/g dw (equivalent to 6.7 ng/g ww)). We also observed regional differences in the PFAS levels with higher concentrations of long-chain PFCAs in Japanese coastal waters than in the South China Sea. The PFAS profiles in shrimp were consistent with those in the diet and serum of Japanese consumers, suggesting that consumption of seafood such as shrimp may be an important source of exposure. The estimated daily intake of sum of all PFAS from shrimp from Japanese coastal water was 0.43 ng/kg body weight/day in average, which could reach the weekly tolerable values (4.4 ng/kg body weight /week) for the sum of the four PFSA set by the EFSA for heavy consumers. The high concentration of PFAS in shrimp warrants further investigation.

Comparison of carbon, nitrogen, and oxygen stable isotope ratios and mercury concentrations in muscle tissues of five beaked whale species and sperm whales stranded in Hokkaido, Japan.

We studied δ13C, δ15N and δ18O values, and total mercury (THg) concentrations in muscle samples from deep-sea predators - five beaked whale species and sperm whales - stranded along the coast of Hokkaido, in the north of Japan in 2010 and 2019. The δ13C, δ15N and δ18O values, THg concentrations, and body length (BL) of Stejneger's beaked whales were similar to those of Hubbs' beaked whales, which belong to the same genus. In contrast, δ13C values, THg concentrations, and BL of Sato's beaked whales were markedly different from those of Baird's beaked whales, which belong to the same genus. Stejneger's and Hubbs' beaked whales living around Hokkaido may compete in their ecological niches, whereas Sato's and Baird's beaked whales may segregate their ecological niches. Although Cuvier's beaked whales and sperm whales belong to different genera and their BLs were significantly different, their δ13C and δ15N values were similar, probably because they can dive and stay in deeper waters than other beaked whale species. The δ13C values in combined samples from all whales increased with increasing BL, probably owing to the larger whale species' dietary preference for squid. The δ13C values in combined samples from all whales were positively correlated with THg concentrations, whereas the δ15N values in the combined samples were negatively correlated. The δ18O values in combined samples from most whales tended to be positively correlated with THg concentrations. These correlations may be explained by a higher THg load from deep-sea feeding than from pelagic feeding and by a feeding shift towards lower trophic levels.

Pharmcokinetic and pharmacodynamic considerations for the anticholinergic burden scale of drugs.

Older adults frequently have many systemic diseases that require treatment with multiple drugs, and thus anticholinergic adverse effect by polypharmacy is a significant concern in the management of older adults. The accuracy of the anticholinergic burden rating may be increased by considering pharmacokinetic and pharmacodynamic factors such as biophase drug concentrations, the pharmacologically active metabolites formed after drug administration, and muscarinic receptor-mediated effects. Therefore, a pharmacological evidence-based burden scale that considers pharmacokinetic and pharmacodynamic factors is expected to be a more optimal tool for precisely assessing the anticholinergic burden, specifically risk reductions in anticholinergic adverse events in the poly-medicated elderly. Geriatr Gerontol Int 2024; 24: 81-87.

Carbon, nitrogen, and oxygen stable isotope ratios of striped dolphins and short-finned pilot whales stranded in Hokkaido, northern Japan, compared with those of other cetaceans stranded and hunted in Japan.

Strandings of striped dolphins (SD) and short-finned pilot whales (PW) in Hokkaido, northern Japan, are rare but have recently increased, probably due to global warming. We quantified δ13C, δ15N, and δ18O in muscles of SD (n = 7) and PW (n = 3) stranded in Hokkaido and compared these values with those in muscles (red meat products) of hunted SD and PW in three areas of central and southern Japan. δ18O in stranded SD, except for the calf, decreased with increasing body length (BL), whereas δ13C increased, with no BL-related changes in δ15N. The variability of δ18O (range of maximum and minimum) was larger in the stranded SD (7.5 ‰) than of the hunted SD in three areas (0.9, 1.9, and 1.4 ‰), whereas that of δ15N was smaller in the stranded SD than in the hunted SD. Similarly, the variability of δ18O was larger in the stranded PW in Hokkaido (3.3 ‰) than in the hunted PW in central Japan (1.4 ‰). The larger variability of δ18O and smaller variability of δ15N in stranded SD imply long-term sojourning in coastal waters and feeding on small amounts of limited prey species at low trophic levels before death.

Profiles and determinants of dicofol, endosulfans, mirex, and toxaphenes in breast milk samples from 10 prefectures in Japan.

Human exposure to persistent organic pollutants (POPs) is reflected by POP concentrations in breast milk. Many studies of POPs in breast milk have been performed in Japan, but insufficient information is available about some legacy POPs (e.g., mirex and toxaphenes, included in the Stockholm Convention in 2001) and novel POPs (e.g., dicofol and endosulfans, included in the Stockholm Convention in 2019 and 2011, respectively). In this study, dicofol, endosulfan, mirex, and toxaphene concentrations in breast milk from 10 prefectures in Japan were determined. The samples were collected between 2005 and 2010, before Stockholm Convention restrictions on endosulfans and mirex were implemented. Common POPs (e.g., polychlorinated biphenyls) were also analyzed to allow the contamination statuses to be compared. The α-endosulfan and ß-endosulfan concentrations were 0.26-13 and 0.012-0.82 ng/g lipid, respectively. The toxaphene #26 and #50 concentrations were <0.08-5.6 and < 0.1-8.5 ng/g lipid, respectively. The dicofol concentrations were <0.01-4.8 ng/g lipid. The mirex concentrations were <0.2-3.5 ng/g lipid. The α- and ß-endosulfan concentrations on a lipid weight basis negatively correlated with the lipid contents of the milk samples (ρ = -0.65, p < 0.01 for α-endosulfan; ρ = -0.58, p < 0.01 for ß-endosulfan). The toxaphene concentrations positively correlated with the lipid contents. The mirex concentrations positively correlated with the maternal age but negatively correlated with the maternal body mass index. No correlations between the dicofol concentrations and the factors were found. Principal component analysis divided the data into four groups, (1) chlordanes, dichlorodiphenyltrichloroethanes and related compounds, hexachlorobenzene, hexachlorocyclohexanes, hexachloroethane, and polychlorinated biphenyls, (2) endosulfans, (3) dicofol, dieldrin, and toxaphenes, and (4) bromodiphenyl ether 47. This indicated that bromodiphenyl ether 47, dicofol, endosulfans, and toxaphenes have different exposure routes or different kinetics to the other legacy POPs.

Teratogenic Effects of Organohalogen Contaminants Extracted from Whale Bacon in a Whole-Rat-Embryo Culture System.

Marine foods can be contaminated with organochlorines and the risk to human beings who consume these foods needs to be evaluated. We examined the teratogenic effects of contaminants extracted from whale bacon on rat embryos using a whole-embryo culture system. Embryonic day 11.5 embryos were cultured for 48 h with organohalogens extracted from whale bacon at low (polychlorinated biphenyls (PCBs): 0.32 ppm, dichlorodiphenyltrichloroethanes (DDTs): 0.16 ppm, chlordanes (CHLs): 0.02 ppm) and high (PCBs: 2.15 ppm, DDTs: 1.99 ppm, CHLs: 0.20 ppm) doses. The levels of organohalogen compounds in cultured embryos were determined. The organochlorine contaminants extracted from whale products were readily transferred to the cultured rat embryos. The number of heartbeats, yolk sac circulation score, and embryonic body circulation score of embryos did not change during the culture period in either exposure group. Cultured embryos treated with the low-dose contaminated medium for 48 h showed abnormalities of the mandible, and craniofacial or forelimb hematomas with an incidence of 50%. All embryos treated with the high-dose medium showed craniofacial abnormalities and cleft lip, and limb abnormalities and hematomas. These results indicate that the organohalogen contaminants in whale bacon may be teratogenic in a dose-dependent manner. Further studies are necessary to determine the dose-effect relationship.

Effects of saw palmetto extract on the vanilloid receptor TRPV1.

OBJECTIVE: Transient receptor potential vanilloid subtype 1 (TRPV1) may play a significant role in the pathophysiology of the bladder. The present study investigated the effects of the herbal product, saw palmetto extract (SPE) on TRPV1-mediated Ca2+ influx and specific [3 H]resiniferatoxin ([3 H]RTX) binding to TRPV1 in HEK293 cells expressing TRPV1 (HEK293VR11 cells). METHODS: Ca2+ influx induced by and the direct binding activity of TRPV1 were measured using a method with Fura 2-AM, a cytoplasmic calcium indicator, and a radioligand binding assay using a [3 H]RTX, respectively. RESULTS: SPE did not markedly affect Ca2+ influx in HEK293VR11 cells; however, it significantly inhibited capsaicin-induced increases in Ca2+ influx in these cells. The specific binding of [3 H]RTX in HEK293VR11 cells was saturable with Kd value of 120 ± 7 pM and Bmax of 1.07 ± 0.10 fmol/mg protein, and was inhibited by low concentrations of non-labeled RTX with Ki of 60.1 ± 7.6 nM. These results confirmed the pharmacological specificity of specific binding sites of [3 H]RTX to TRPV1 in HEK293VR11 cells. SPE inhibited the specific binding of [3 H]RTX in a concentration-dependent manner, with Ki of 24.2 ± 1.4 µg/mL. CONCLUSIONS: The present study demonstrated for the first time, that SPE inhibited capsaicin-induced Ca2+ influx with binding to TRPV1 in HEL293VR11 cells. These results will contribute to a more detailed understanding of the pharmacological effects of SPE on urinary dysfunction.

Comparative characterization of ß-adrenoceptors in the bladder, heart, and lungs of rats: Alterations in spontaneously hypertensive rats.

The present study aimed to characterize and compare ß-adrenoceptors in the rat bladder with those in the heart and lungs of SD rats (8-10 weeks old) using subtype-selective agonists and antagonists in a radioligand binding assay with (-)-[125I]cyanopindolol ([125I]CYP), and also to clarify alterations in ß-adrenoceptors in the bladder of spontaneously hypertensive rats (SHR) at 14 weeks old, from those of Wistar-Kyoto rats (WKY) and Wistar rats at the same age. A radioligand binding assay with [125I]CYP was used to measure ß-adrenoceptor binding activity in rat tissues. Metoprolol exhibited the highest affinity to specific binding sites of [125I]CYP in the rat heart, indicating the dominance of ß1-adrenoceptors. ß3-selective agonists (BRL37344 and CL316243) and antagonist (SR59230A) exhibited higher affinity to specific binding sites of [125I]CYP in the bladder than in the heart and lungs. Furthermore, the binding affinity of the ß2-selective antagonist, ICI118551 was the highest in the bladder. The Bmax of specific [125]CYP binding in the bladder was significantly lower in WKY and SHR than in Wistar rats. The present study provides further evidence for the coexistence of ß2-and ß3-adrenoceptors in the rat bladder, and indicates that ß-adrenoceptor density is lower in the bladders of WKY and SHR.

Anti-Allergic Effects of the Subcritical Water Extract Powder of Citrus unshiu in Mouse and Guinea Pig Models.

We evaluated the effects of unripe mandarin orange (Citrus unshiu) extract powder (unripe mandarin extract powder [UMEP]) treated with subcritical water on allergic diseases by using animal models. High performance liquid chromatography (HPLC) analysis revealed that subcritical water is a more effective solvent than alcohol and hot water, as it quickly extracted approximately 90% of the functional compounds narirutin (1) and hesperidin (2) from whole fruits. Repeated oral administration of UMEP significantly reversed the peripheral blood flow decline observed during the promotion of allergies after sensitization with the antigen, hen egg-white lysozyme (HEL). UMEP also significantly inhibited compound 48/80-induced scratching behavior in HEL-sensitized mice, which are more sensitive to itching stimuli than are normal mice, without suppressing locomotor activity. In addition, repeated oral administration of UMEP in ovalbumin-challenged guinea pigs significantly suppressed the late phase of nasal airway resistance. This study provides evidence that the subcritical water extract powder of unripe C. unshiu fruit is an effective anti-allergic functional food.

Effects of perfluoroalkyl carboxylic acids on the uptake of sulfobromophthalein via organic anion transporting polypeptides in human intestinal Caco-2 cells.

We performed a detailed investigation of the uptake of sulfobromophthalein (BSP) from the apical membrane of Caco-2 cells, which is a substrate for organic anion transporting polypeptides (OATPs), and calculated the kinetic parameters of BSP uptake as follows: Km = 13.9 ± 1.3 µM, Vmax = 1.15 ± 0.07 nmol (mg protein)-1 (5 min)-1, and kd = 38.2 ± 0.53 µL (mg protein)-1 (5 min)-1. Coincubation with medium-chain (C7-C11) perfluoroalkyl carboxylic acids (PFCAs), such as perfluoroheptanoic acid (PFHpA, C7), perfluorooctanoic acid (PFOA, C8), perfluorononanoic acid (PFNA, C9), perfluorodecanoic acid (PFDA, C10) and perfluoroundecanoic acid (PFUnDA, C11), significantly decreased BSP uptake by 27-55%, while coincubation with short- (C3-C6) and long-chain (C12-C14) PFCAs decreased the uptake only slightly. Dixon plotting suggested that PFOA, PFNA and PFDA competitively inhibited the BSP uptake with inhibition constant (Ki) values of 62.2 ± 1.3 µM, 35.3 ± 0.1 µM and 43.2 ± 0.3 µM, respectively. PFCAs with medium-chains could be substrates for OATPs, probably OATP2B1, which is the most abundantly expressed OATP isoform in Caco-2 cells.

Kanechlor 500-mediated changes in serum and hepatic thyroxine levels primarily occur in a transthyretin-unrelated manner.

The effects of Kanechlor-500 (KC500) on the levels of serum total thyroxine (T4 ) and hepatic T4 in wild-type C57BL/6 (WT) and its transthyretin (TTR)-deficient (TTR-null) mice were comparatively examined. Four days after a single intraperitoneal injection with KC500 (100 mg/kg body weight), serum total T4 levels were significantly decreased in both WT and TTR-null mice. The KC500 pretreatment also promoted serum [125 I]T4 clearance in both strains of mice administrated with [125 I]T4 , and the promotion of serum [125 I]T4 clearance in WT mice occurred without inhibition of the [125 I]T4 -TTR complex formation. Furthermore, the KC500 pretreatment led to significant increases in liver weight, steady-state distribution volume of [125 I]T4 , hepatic accumulation level of [125 I]T4 , and concentration ratio of the liver to serum in both strains of mice. The present findings indicate that the KC500-mediated decrease in serum T4 level occurs in a TTR-unrelated manner and further suggest that KC500-promoted T4 accumulation in the liver occurs through the development of liver hypertrophy and the promotion of T4 transportation from serum to liver.

Muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine, and tolterodine in rat tissues after the oral, intravenous, or intravesical administration.

The present study aimed to characterize muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine (5-HMT), and tolterodine in bladder and other tissues of rats after their oral, intravenous, or intravesical administration. Muscarinic receptors in tissues were measured by using [N-methyl-3H]scopolamine methyl chloride ([3H]NMS). The in vitro binding affinity for muscarinic receptors was the highest by 5-HMT, followed by tolterodine and fesoterodine. Fesoterodine exhibited lower affinity in rat submaxillary gland than in detrusor muscle and urothelium. Muscarinic binding affinities of 5-HMT and tolterodine were similar among tissues. The duration of binding of oral fesoterodine to muscarinic receptors was longer in bladder than in submaxillary gland, heart, and lung, and its binding was little observed in colon and cerebral cortex. Binding activity of intravenous 5-HMT to muscarinic receptors was significantly observed in all tissues, except cerebral cortex, with a longer duration in bladder. Significant binding of bladder detrusor and urothelial muscarinic receptors was observed following intravesical instillation of 5-HMT. This selectivity may be attributed to the direct blockade of bladder receptors by excreted urinary 5-HMT. Thus, fesoterodine may be efficacious as a treatment for patients with overactive bladder.

Levels and profiles of long-chain perfluoroalkyl carboxylic acids in Pacific cod from 14 sites in the North Pacific Ocean.

We investigated the profiles and levels of perfluoroalkyl carboxylic acid (PFCA) contamination in Pacific cod (Gadus macrocephalus) from the North Pacific Ocean. The mean concentrations of PFCAs containing 8 to 14 carbon atoms (C8-C14) in edible Pacific cod muscle ranged from 216 to 670 pg g-1 wet weight in the Northeast Pacific Ocean (Seattle, Vancouver, Alaska, and Russia), from 819 to 1710 pg g-1 wet weight in Japanese coastal waters (Hokkaido, Aomori, Iwate, Miyagi, Tottori, and Shimane), and from 288 to 892 pg g-1 wet weight in Korean waters (Sokcho, Busan, and Yeosu). These results indicate there are geographical differences in the distribution of PFCAs. The long-chain PFCAs (C9-C14) contributed 96% of the total PFCA concentration across Japan, whereas they contributed only 33% of the total PFCA concentration in the USA and Canada. Long-chain PFCA concentrations in cod samples collected in Japanese and Korean waters were about three to four times those in samples from the USA, Canada, and Russia. Because seafood is considered an important dietary source of PFCAs, high concentrations of long-chain PFCAs in Pacific cod from Japanese and Korean waters may affect human dietary exposure and blood concentrations of long-chain PFCAs.

Different profiles of naturally produced and anthropogenic organohalogens in the livers of cetaceans from the Sea of Japan and the North Pacific Ocean.

Levels and profiles of naturally produced halogenated bipyrroles (Br4Cl2-DBP and Cl7-MBP), methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47), anthropogenic perfluoroalkyl substances (PFASs) and legacy persistent organic pollutants (POPs) were investigated in the livers of 14 cetaceans from the Sea of Japan and the North Pacific Ocean. The concentrations of Br4Cl2-DBP (4 to 4900 ng/g-wet), Cl7-MBP (16 to 3960 ng/g-wet) and 6-MeO-BDE47 (7 to 190 ng/g-wet) were higher in the order of killer whales > toothed whales > baleen whales. Profiles of PFASs were dominated by perfluoroundecanoic and perfluorotridecanoic acids (10 to 540 ng/g-wet), sum of which accounted for 70% of total measured PFASs. Regional difference was observed for Cl7-MBP and PFASs, which were higher in the Sea of Japan, whereas Br4Cl2-DBP was in the North Pacific Ocean. Specific accumulation pattern of these natural contaminants in cetaceans around northern Japan could help compare the exposure profile of PFASs and POPs among other geographic regions.

Data on COA-Cl administration to the APP/PS2 double-transgenic mouse model of Alzheimer׳s disease: Improved hippocampus-dependent learning and unchanged spontaneous physical activity.

We herein present behavioral data regarding whether COA-Cl, a novel adenosine-like nucleic acid analog that promotes angiogenesis and features neuroprotective roles, improves cognitive and behavioral deficits in a murine model for Alzheimer׳s disease (AD). COA-Cl induced significant spatial memory improvement in the amyloid precursor protein/presenilin 2 double-transgenic mouse model of AD (PS2Tg2576 mice). Correspondingly, non-spatial novel object cognition test performance also significantly improved in COA-Cl-treated PS2Tg2576 mice; however, these mice demonstrated no significant changes in physical activity or motor performance. COA-Cl did not change the spontaneous activities and cognitive ability in the wild-type mice.

Contamination trends and factors affecting the transfer of hexabromocyclododecane diastereomers, tetrabromobisphenol A, and 2,4,6-tribromophenol to breast milk in Japan.

This study investigated contamination trends and factors affecting the levels of brominated flame retardants (BFRs), including hexabromocyclododecane (HBCD) diastereomers, tetrabromobisphenol A (TBBP-A), and 2,4,6-tribromophenol (2,4,6-TBP), in breast milk in Japan. Breast milk samples (n = 64) were collected from mothers living in six prefectures in Japan. The mean concentrations were 2.2, 0.19, 0.29, 3.0, and 0.59 ng/g lipid weight for α-HBCD, ß-HBCD, γ-HBCD, TBBP-A, and 2,4,6-TBP, respectively. Based on the previous studies, the levels of ΣHBCD in Japanese women's milk appear to be increasing, and the levels of TBBP-A are higher than those in other Asian countries. Although ΣHBCD were not correlated to phenolic BFRs, the concentration of ß-HBCD was significantly correlated to the concentrations of TBBP-A (r = 0.440, p < 0.01) and 2,4,6-TBP (r = 0.320, p < 0.01). The concentration of γ-HBCD increased significantly with maternal age (r = 0.378, p < 0.01), but the concentrations of the other analytes were not dependent on age. The concentration of α-HBCD was higher in primiparae than in multiparae (p < 0.05), while TBBP-A was higher in multiparae. No significant correlation was found between the phenolic BFR levels in milk and mothers' age, working place, and drinking/smoking habits. These results suggest that exposure to α- and γ-HBCD diastereomers could be affected by maternal age and parity, respectively, because of their different kinetics and sources. Therefore, these factors should be considered when conducting infant risk assessments.

A Real-Time Ultraviolet Radiation Imaging System Using an Organic Photoconductive Image Sensor.

We have developed a real time ultraviolet (UV) imaging system that can visualize both invisible UV light and a visible (VIS) background scene in an outdoor environment. As a UV/VIS image sensor, an organic photoconductive film (OPF) imager is employed. The OPF has an intrinsically higher sensitivity in the UV wavelength region than those of conventional consumer Complementary Metal Oxide Semiconductor (CMOS) image sensors (CIS) or Charge Coupled Devices (CCD). As particular examples, imaging of hydrogen flame and of corona discharge is demonstrated. UV images overlapped on background scenes are simply made by on-board background subtraction. The system is capable of imaging weaker UV signals by four orders of magnitude than that of VIS background. It is applicable not only to future hydrogen supply stations but also to other UV/VIS monitor systems requiring UV sensitivity under strong visible radiation environment such as power supply substations.