Using a full thickness bioengineered human skin equivalent as a model for radiation biology research

BackgroundPrevious research revealed a lack of comfort and knowledge regarding nuclear and radiological events among medical staff. We investigated the awareness and knowledge of radiological and nuclear events among the Japanese medical staff by comparing differences by occupation (doctors, nurses, and other medical specialists).MethodsWe conducted a cross-sectional questionnaire survey among trainees undergoing Japanese disaster medical training courses between July 2014 and February 2016. The differences by occupation were evaluated for all questions on awareness and knowledge concerning disasters or radiological and nuclear events and demographics.ResultsAmong the occupations, there were significant differences in the willingness to work onsite based on the types of disaster, familiarity with the national disaster medical response system, the accuracy rate of some knowledge about medical practice and the risk, and demographic characteristics such as practical experience and educational degree. The accuracy rates of responses to some questions on knowledge were very low in all occupations.ConclusionThere were significant differences in awareness and knowledge of radiological and nuclear events by occupation. We believe that the results can be used to develop and modify the content of training courses on radiological and nuclear events to make such courses beneficial for each healthcare worker.

2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside is the main compound of Polygonum multiflorum . There are two geometrical isomers of 2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside. Several studies have shown that cis ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside may be the risk compound of hepatotoxicity in Polygonum multiflorum Thunb. and there are few comprehensive comparisons on the different impacts of cis ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside and trans ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside about metabolic characteristics. This paper aimed to provide a comprehensive assessment of the metabolomics and lipidomics studies of the differences in metabolic characteristics of cis ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside and trans ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside. The results showed that trans ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside and cis ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside significantly affected 47 metabolites. The main interfering pathways included alpha‐linolenic acid, linoleic acid (LA) metabolism, arachidonic acid (AA) metabolism, and fatty acid metabolism. According to the transcriptomics study, the altered genes were mainly enriched in LA metabolism, AA metabolism, and fatty acid metabolism. Two genes ( Runx3 and Scd1 ) were mainly involved in the cell cycle and fatty acid metabolism in the cis ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside group, and one enzyme (Phospholipase B1) was related to alpha‐linolenic acid, LA metabolism and AA metabolism in the trans ‐2,3,5,4′‐tetrahydroxy stilbene‐2‐ O‐β ‐D‐glucoside group. These would provide useful information for further investigation on therapeutic and hepatotoxic mechanisms of Polygonum multiflorum Thunb.

The capacity for 5-lipoxygenase (5-LO) metabolism of endogenous arachidonic acid (AA) is greater in alveolar macrophages (AM) than in their circulating precursors, peripheral blood monocytes (PBM); however, the ability of PBM to metabolize exogenous AA to 5-LO products is comparable to that of AM. In the present study, we examined the enzymatic mechanisms by which 5-LO metabolism of AA is altered during differentiation of PBM in the lung. Resting human AM exhibited greater steady-state levels of 5-LO (7-fold) and LTA4 hydrolase (2-fold) proteins than autologous PBM; moreover, they differed from PBM in that they contained a significant amount of 5-LO associated with the particulate fraction. Importantly, AM contained 40-fold more 5-lipoxygenase activating protein (FLAP) than did PBM, which correlated well with the relative abilities of intact AM and PBM to metabolize endogenous AA to leukotrienes. The FLAP inhibitor MK-886 was unable to block leukotriene synthesis from exogenous AA in the two cell types, despite its ability to completely inhibit 5-LO metabolism of endogenous AA. These observations indicate that, although FLAP is essential for the synthesis of leukotrienes from endogenous AA, perhaps by presenting AA to 5-LO, it is not required for 5-LO metabolism of exogenous AA. The differing roles of FLAP in 5-LO metabolism of endogenous versus exogenous AA are consistent with the conclusion that it is the markedly greater expression of FLAP, rather than of 5-LO, that is primarily responsible for the increased leukotriene synthesis from endogenous AA that accompanies PBM differentiation into AM.

Gout is an acute rheumatic disorder that occurs in connection with the deposition of monosodium urate (MSU) crystals in the joints. This disease is characterized by intermittent episodes of severe pain and inflammatory joint swelling which are seemingly driven by prostaglandins. In this study we investigated the effect of MSU crystals on arachidonic acid (AA) metabolism in the mouse. We have demonstrated that prostaglandins and other AA metabolites were transiently formed after MSU crystal injection with peak levels occurring after 10 min. In contrast, free AA levels remained high for 2-4 hours after MSU crystal injection. By contrast, when exogenous AA was administered instead of MSU crystals, both the eicosanoids and AA diminished at the same high rates. The metabolism of exogenously administered AA to eicosanoids was inhibited by pretreatment with MSU crystals. No inhibition of AA metabolism was observed when mice were pretreated with AA itself, Ca2+ ionophore (A23187), or zymosan. We conclude that the MSU crystal treatment of mice results in a transient eicosanoid production which is followed by attenuated AA metabolism. It could be that MSU crystals similarly inhibit AA metabolism in gout and thereby limit the duration of gout attacks.

Evidence for a new human CYP1A1 regulation pathway involving PPAR-α and 2 PPRE sites

Cultured alveolar type II cells can liberate esterified arachidonic acid (AA) and metabolize it predominantly via the cyclooxygenase pathway, and their capacity to do so increases as they alter their phenotype over time in culture. Little is known, however, about the regulation of AA metabolism in alveolar pneumocytes. We have examined the effects of protein kinase C (PKC) activation on arachidonate metabolism in primary cultures of rat alveolar epithelial cells studied at 2 and 7 days following isolation. The potent PKC activator phorbol myristate acetate (PMA) stimulated dose-dependent increases in free AA levels in both day 2 and day 7 cultures, with optimal stimulation at 50 nM. Greater stimulation was demonstrated for day 7 cells, and this was associated with greater prostanoid synthesis in response to PMA by day 7 than by day 2 cells. The capacity of PMA to "prime" epithelial cells for augmented AA liberation and metabolism in response to calcium ionophore A23187 (5 microM) was examined also. Significant priming by PMA was observed in both day 2 and day 7 cells; once again, augmentation of both free AA levels as well as prostaglandin E2 levels was greater for day 7 cells than for day 2 cells. That the capacity of PMA to modulate AA metabolism was mediated by activation of PKC was confirmed by demonstrating that (1) phorbol didecanoate, which lacks the ability to activate PKC, failed to activate AA metabolism; (2) pretreatment for 18 h with 1 microM PMA, which depletes cellular PKC, abolished subsequent AA metabolism activated by 50 nM PMA; and (3) the PKC inhibitor staurosporine abrogated increases in the quantities of both free AA and prostaglandin E2 in response to PMA. We conclude that activation of PKC increases the availability of AA for prostanoid synthesis in alveolar pneumocytes, and that this effect is more evident as type II cell differentiation is modeled during prolonged cultivation.

This paper investigates the possible existence of a power law relationship between the frequency (the rate of event occurrences) and the severity of nuclear and radiological events. To the best of our knowledge this is the first study on the existence of possible scaling laws for such types of events. Two relevant databases (the ETH Zurich curated nuclear events database and the Database of Radiological Incidents and Related Events) were used in this study. It was found from both databases that the time intervals between successive nuclear events (at nuclear power plants and other facilities) follow an exponential distribution. The results of the statistical analysis with higher sensitivity to tail distributions showed that the available data related to the severity of nuclear events may follow a power law. The question of possible safety-related consequences of accident tolerance strategies is also touched upon.

Recent studies indicate that both arachidonic acid (AA) metabolism and phospholipid (PL) metabolism are markedly stimulated during the release of mediators from mast cells. The relationship between stimulated AA metabolism and stimulated PL metabolism in isolated rat mast cells was investigated and then correlated with the secretory process. ETYA (5,8,11,14-eicosatetraynoic acid, a known inhibitor of cyclooxygenase and lipoxygenase pathways of AA metabolism) inhibited 32PO4 incorporation into phosphatidic acid (PA), phosphatidylinositol (PI), and phoshodidylcholine (PC) in both unstimulated mast cells and mast cells stimulated by cross-linking of surface IgE molecules. ID50 values for inhibition of mediator release and of basal and stimulated 32PO4 incorporation into PL were 50 to 60 microM ETYA. Indomethacin (1 to 10 microM) and aspirin (10 to 100 microM) had no significant effect on 32PO4 incorporation or on mediator release. AA (10 microM) inhibited PL labeling in resting mast cells and rendered the cells less responsive to secretory signals. Preincubation of the cells with indomethacin (1 microM) blocked both of these AA effects. When AA was added to stimulated mast cells, however, both PL labeling and mediator release were enhanced. Thus, each of the alterations in AA metabolism caused parallel changes in mast cell PL metabolism and in mediator release. Since both basal and stimulated PL metabolism were modified by ETYA and AA, some form of direct regulation of mast cell PL metabolism by AA metabolites seems likely. The close parallelism of effects on mediator release and on PL metabolism suggests that modulation of mast cell function by AA metabolites may be mediated at lest in part by effects on lipid metabolism.

HIV-1 transgenic (Tg) rats, a model for human HIV-1 associated neurocognitive disorder (HAND), show upregulated markers of brain arachidonic acid (AA) metabolism with neuroinflammation after 7months of age. Since lithium decreases AA metabolism in a rat lipopolysaccharide model of neuroinflammation, and may be useful in HAND, we hypothesized that lithium would dampen upregulated brain AA metabolism in HIV-1 Tg rats. Regional brain AA incorporation coefficients k* and rates J ( in ), markers of AA signaling and metabolism, were measured in 81 brain regions using quantitative autoradiography, after intravenous [1-(14) C]AA infusion in unanesthetized 10-month-old HIV-1 Tg and age-matched wildtype rats that had been fed a control or LiCl diet for 6weeks. k* and J ( in ) for AA were significantly higher in HIV-1 Tg than wildtype rats fed the control diet. Lithium feeding reduced plasma unesterified AA concentration in both groups and J ( in ) in wildtype rats, and blocked increments in k* (19 of 54 regions) and J ( in ) (77 of 81 regions) in HIV-1 Tg rats. These in vivo neuroimaging data indicate that lithium treatment dampened upregulated brain AA metabolism in HIV-1 Tg rats. Lithium may improve cognitive dysfunction and be neuroprotective in HIV-1 patients with HAND through a comparable effect.

The role of oxidized plasma lipoproteins in modifying arachidonic acid (AA) metabolism was studied in smooth muscle cells (SMC). Very low density lipoproteins (VLDL), unoxidized low density lipoproteins (LDLBHT) isolated with butylated hydroxytoluene (BHT), and oxidized LDL (LDLOXID) were separated from human serum. Thiobarbituric acid reactant (TBAR) levels were adjusted by saline incubations. Prostanoids in guinea pig SMC cultures were measured either by radioimmunoassay (RIA) or the isolation by high performance liquid chromatography (HPLC) of labeled prostanoids from SMC prelabeled with [14C]AA. Cell morphology and viability were studied by staining with Giemsa, nile red, and propidium iodide. VLDL and LDLBHT had little effect on prostanoid synthesis. Low-TBAR-LDLOXID enhanced total prostanoid levels and diminished the release of labeled prostanoids. Similar effects were found with exogenous free AA (unlabeled). Low-TBAR-LDLOXID did not affect the release of endogenous phospholipid AA as free AA. Synergism occurred between LDLOXID and exogenous free AA in prostanoid synthesis. Low-TBAR-LDLOXID evidently enhanced prostanoid levels in SMC both by supplying AA and by stimulating cyclooxygenase. High-TBAR-LDLOXID blocked prostanoid synthesis and enhanced cell death but time and pulse-recovery experiments showed that these effects were unrelated. High-TBAR-LDLOXID stimulated prostanoid synthesis when BHT was added to the incubation media. High-TBAR-LDLOXID also caused massive free AA release and the formation of many nonprostanoid derivatives. High-TBAR-LDLOXID evidently diminished overall prostanoid levels in SMC by inhibiting cyclooxygenase and at the same time stimulating AA release and the formation of other AA derivatives.

Since the development of x-rays in the late 19th century, radiation has increasingly been used for diagnostic imaging and various industrial purposes. The human health consequences of radiation exposure can range from minor asymptomatic exposures to the development of potentially fatal acute radiation sickness depending on the characteristics of the exposure. This review provides an overview of radiation injury, including historical perspective and principles of toxicity; assessment and stabilization (bedside evaluation, supportive care, and empirical therapy); diagnosis (estimation of radiation dose, laboratory assessment, biodosimetry and bioassays, smoke inhalation, and psychiatric sequelae); treatment and disposition (hematologic acute radiation illness, countermeasures and antidotes, gastrointestinal symptoms, fluid and electrolyte management, surgical intervention, local radiation injury, psychiatric treatment, radiation exposure during pregnancy, palliative care, and disposition); and outcomes (carcinogenesis, noncancer effects). Tables include the characteristic of common radioactive isotopes, common radiation dose equations and conversions, prescribing information for colony-stimulating factors, recommended antimicrobial prophylaxis and treatment regimens, and radioisotope decorporation or blocking agents. Figures show types of ionizing radiation, comparison of radiation contamination and exposure, patterns of early lymphocyte response based on radiation dose, the relationship between time to onset of vomiting and radiation dose, and a sample body chart for documentation of radiation contamination. This review contains 5 figures, 5 tables, and 82 references. Key Words: radiation, radiation exposure, radiation sickness, diagnostic imaging, pregnancy, carcinogenesis, toxicity, acute radiation syndrome (ARS)

We have studied the regulation of arachidonic acid (AA) uptake, metabolism, and release in Aplysia nervous system. Following uptake of [3H]AA, the distribution of radioactivity in intracellular and extracellular lipid pools was measured as a function of time in the presence or absence of exogenous AA. The greatest amount of AA was esterified into phosphatidylinositol (relative to pool size). We found that the intracellular free AA pool underwent rapid turnover, and that radioactive free AA and eicosanoids were released at a rapid rate into the extracellular medium, both in the presence and absence of exogenous AA. Most of the released radioactivity originated from phosphatidylinositol. Two pharmacological agents were found to modulate AA metabolism in Aplysia ganglia. The phorbol ester, 12-O-tetradecanoylphorbol 13-acetate, stimulated liberation of AA from phosphatidylinositol and phosphatidylcholine. This resulted in an increase in free internal and secreted AA, an increase in conversion of AA to eicosanoids, and an increase in esterification of AA into triacylglycerol. The half maximal dose for TPA-stimulated AA turnover was 15 nM, and the stimulation was dependent on the presence of extracellular calcium. 4-bromophenacylbromide inhibited the redistribution of radioactivity from phospholipid into triacylglycerol, indicating BPB was acting as a phospholipase inhibitor in Aplysia as it does in other systems. These pharmacological agents, in addition to providing information about the regulation of AA metabolism and release, are useful tools for investigating the physiological function of the rapid turnover of AA in Aplysia nervous system.

ABSTRACTDengue is an acute febrile illness caused by dengue virus (DENV) and a major cause of morbidity and mortality in tropical and subtropical regions of the world. The lack of an appropriate small-animal model of dengue infection has greatly hindered the study of dengue pathogenesis and the development of therapeutics. In this study, we conducted mass spectrometry-based serum metabolic profiling from a model using humanized mice (humice) with DENV serotype 2 infection at 0, 3, 7, 14, and 28 days postinfection (dpi). Forty-eight differential metabolites were identified, including fatty acids, purines and pyrimidines, acylcarnitines, acylglycines, phospholipids, sphingolipids, amino acids and derivatives, free fatty acids, and bile acid. These metabolites showed a reversible-change trend—most were significantly perturbed at 3 or 7 dpi and returned to control levels at 14 or 28 dpi, indicating that the metabolites might serve as prognostic markers of the disease in humice. The major perturbed metabolic pathways included purine and pyrimidine metabolism, fatty acid β-oxidation, phospholipid catabolism, arachidonic acid and linoleic acid metabolism, sphingolipid metabolism, tryptophan metabolism, phenylalanine metabolism, lysine biosynthesis and degradation, and bile acid biosynthesis. Most of these disturbed pathways are similar to our previous metabolomics findings in a longitudinal cohort of adult human dengue patients across different infection stages. Our analyses revealed the commonalities of host responses to DENV infection between humice and humans and suggested that humice could be a useful small-animal model for the study of dengue pathogenesis and the development of dengue therapeutics.IMPORTANCE Dengue virus is the most widespread arbovirus, causing an estimated 390 million dengue infections worldwide every year. There is currently no effective treatment for the disease, and the lack of an appropriate small-animal model of dengue infection has greatly increased the challenges in the study of dengue pathogenesis and the development of therapeutics. Metabolomics provides global views of small-molecule metabolites and is a useful tool for finding metabolic pathways related to disease processes. Here, we conducted a serum metabolomics study on a model using humanized mice with dengue infection that had significant levels of human platelets, monocytes/macrophages, and hepatocytes. Forty-eight differential metabolites were identified, and the underlying perturbed metabolic pathways are quite similar to the pathways found to be altered in dengue patients in previous metabolomics studies, indicating that humanized mice could be a highly relevant small-animal model for the study of dengue pathogenesis and the development of dengue therapeutics.

Untargeted and targeted metabolomics profiling reveals the underlying pathogenesis and abnormal arachidonic acid metabolism in laying hens with fatty liver hemorrhagic syndrome

The mechanisms of preterm labour; the interaction between amnion cells and leukocytes in the metabolism of arachidonic acid