Nrf2 Antioxidative System is Involved in Cytochrome P450 Gene Expression and Activity: A Delay in Pentobarbital Metabolism in Nrf2-Deficient Mice.

NF-E2-related factor 2 (Nrf2) is a transcriptional regulator of biologic defense proteins, such as antioxidant proteins and phase II detoxification enzymes. Cytochrome P450 (P450) enzymes have been shown to regulate phase I metabolism of various drugs and are partially regulated by Nrf2; however, the influence of Nrf2 on drug pharmacokinetics is not known. Here, we showed that Nrf2 depletion prolonged the effect of pentobarbital, a sleep-promoting drug. Pretreatment with phenobarbital, a P450 inducer, shortens the sleeping time associated with pentobarbital-induced sedation in wild-type (WT) mice; however, this effect was not observed in Nrf2-/- mice. Furthermore, the blood pentobarbital concentration was higher in Nrf2-/- mice than in WT mice at 30-60 minutes, and the phenobarbital-induced enhancement of its clearance was attenuated in Nrf2-/- mice compared with WT mice. Total P450 content was decreased in Nrf2-/- mouse livers, and the phenobarbital-induced increase in P450 content was lower in Nrf2-/- mice than WT mice. Cyp1a2, Cyp2a5, Cyp2c29, and Cyp2e1 gene expression levels under physiologic conditions and Cyp1a2, Cyp2a5, and Cyp2b10 gene expression levels under phenobarbital-treated conditions were lower in Nrf2-/- mice compared with WT mice. Additionally, pentobarbital metabolism in liver microsomes was attenuated by Nrf2 depletion. Taken together, these findings suggested that Nrf2 influenced pentobarbital pharmacokinetics through the regulation of drug metabolism and P450 gene expression. Thus, Nrf2-mediated regulation of P450 may contribute to the biologic defense against increased reactive oxygen species production. SIGNIFICANCE STATEMENT: NF-E2-related factor 2 (Nrf2) plays a critical role in the cellular defense against oxidative stress. Nrf2-/- mice with reduced ability to eliminate reactive oxygen species (ROS) showed a significant delay in emergence from pentobarbital-induced sleep, which was associated with decreased P450 activities and gene expression. Our findings provide that Nrf2 dysfunction or ROS that exceed a threshold level of the eliminating ability of the Nrf2 system may reduce P450 activity.

Redox-sensitive transcription factor Nrf2 regulates vascular smooth muscle cell migration and neointimal hyperplasia.

OBJECTIVE: Reactive oxygen species are important mediators for platelet-derived growth factor (PDGF) signaling in vascular smooth muscle cells, whereas excess reactive oxygen species-induced oxidative stress contributes to the development and progression of vascular diseases, such as atherosclerosis. Activation of the redox-sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), is pivotal in cellular defense against oxidative stress by transcriptional upregulation of antioxidant proteins. This study aimed to elucidate the role of Nrf2 in PDGF-mediated vascular smooth muscle cell migration and neointimal hyperplasia. APPROACH AND RESULTS: PDGF promoted nuclear translocation of Nrf2, followed by the induction of target genes, including NAD(P)H:quinone oxidoreductase-1, heme oxygenase-1, and thioredoxin-1. Nrf2 depletion by small interfering RNA enhanced PDGF-promoted Rac1 activation and reactive oxygen species production and persistently phosphorylated downstream extracellular signal-regulated kinase-1/2. Nrf2 depletion enhanced vascular smooth muscle cell migration in response to PDGF and wound scratch. In vivo, Nrf2-deficient mice showed enhanced neointimal hyperplasia in a wire injury model. CONCLUSIONS: These findings suggest that the Nrf2 system is important for PDGF-stimulated vascular smooth muscle cell migration by regulating reactive oxygen species elimination, which may contribute to neointimal hyperplasia after vascular injury. Our findings provide insight into the Nrf2 system as a novel therapeutic target for vascular remodeling and atherosclerosis.

PACAP38 differentially effects genes and CRMP2 protein expression in ischemic core and penumbra regions of permanent middle cerebral artery occlusion model mice brain.

Pituitary adenylate-cyclase activating polypeptide (PACAP) has neuroprotective and axonal guidance functions, but the mechanisms behind such actions remain unclear. Previously we examined effects of PACAP (PACAP38, 1 pmol) injection intracerebroventrically in a mouse model of permanent middle cerebral artery occlusion (PMCAO) along with control saline (0.9% NaCl) injection. Transcriptomic and proteomic approaches using ischemic (ipsilateral) brain hemisphere revealed differentially regulated genes and proteins by PACAP38 at 6 and 24 h post-treatment. However, as the ischemic hemisphere consisted of infarct core, penumbra, and non-ischemic regions, specificity of expression and localization of these identified molecular factors remained incomplete. This led us to devise a new experimental strategy wherein, ischemic core and penumbra were carefully sampled and compared to the corresponding contralateral (healthy) core and penumbra regions at 6 and 24 h post PACAP38 or saline injections. Both reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were used to examine targeted gene expressions and the collapsin response mediator protein 2 (CRMP2) protein profiles, respectively. Clear differences in expression of genes and CRMP2 protein abundance and degradation product/short isoform was observed between ischemic core and penumbra and also compared to the contralateral healthy tissues after PACAP38 or saline treatment. Results indicate the importance of region-specific analyses to further identify, localize and functionally analyse target molecular factors for clarifying the neuroprotective function of PACAP38.

Paternal methamphetamine exposure differentially affects first and second generations in mice.

Amphetamine-type stimulants are abused worldwide, and methamphetamine (METH) accounts for a large majority of seized abused drug cases. Recently, the paternal origin of health and disease theory has been proposed as a concept wherein paternal factors influence descendants. Although METH abuse is more common among males, its effects on their descendants were not examined. Therefore, we investigated the effects of paternal METH exposure on F1 and F2 levels in a mouse model. Sires were administered METH for 21 days and mated with female mice to obtain F1 mice. Growth evaluations (number of births, survival rate, body weight, righting reflex, cliff avoidance tests, and wire-hanging maneuver) were performed on F1 mice. Upon reaching six weeks of age, the mice were subjected to spontaneous locomotion, elevated plus-maze, acute METH treatment, and passive avoidance tests. Additionally, RNA-seq was performed on the striatum of male mice. Male F1 mice were mated with female mice to obtain F2 mice. They were subjected to the same tests as the F1 mice. Paternal METH exposure resulted in delayed growth and decreased memory function in F1 mice, overweight in F2 mice, decreased METH sensitivity, and reduced anxiety-related behaviors in female F2 mice. Enrichment analysis revealed significant enrichment of terms related to behavior in F1 and protein folding in F2. These results indicated that the effects of paternal METH exposure vary across generations. The effects of paternal factors need to be examined not only in F1, but also in F2 and beyond.

Fatal poisoning due to ingestion of boiled oleander leaf extract.

Nerium oleander is an ornamental evergreen shrub belonging to the family Apocynaceae. The Apocynaceae family includes the attractive evergreen shrub known as oleander. The cardiotoxic glycoside, oleandrin, is present in all portions of the common oleander plant. Oleander consumption can result in deadly situations accidentally or as a suicide attempt. After consuming kettle-boiled oleander leaf extract as part of a suicide attempt, an 80-year-old man was discovered comatose in his home and taken to our emergency room. The patient's heart rate was 30 beats per minute, and he had hypotension. Arterial blood gas analysis revealed remarkable metabolic acidosis and hyperkalemia (K: 7.7 mEq/L). An electrocardiogram showed a wide QRS wave, similar to a sine curve. The patient collapsed following cardiac arrest soon after hospital arrival. Veno-arterial extracorporeal membrane oxygenation was initiated; however, the patient eventually died. The serum level of oleandrin at hospital arrival, subsequently measured by LC-MS/MS, was found to be 33.4 ng/mL, far above the levels reported in previous fatal cases.

Severe aconite poisoning successfully treated with veno-arterial extracorporeal membrane oxygenation: A case report.

BACKGROUND: Most species of aconite contain highly toxic aconitines, the oral ingestion of which can be fatal, primarily because they cause ventricular arrhythmias. We describe a case of severe aconite poisoning that was successfully treated through veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and in which detailed toxicological analyses of the aconite roots and biological samples were performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). CASE SUMMARY: A 23-year-old male presented to the emergency room with circulatory collapse and ventricular arrhythmia after ingesting approximately half of a root labeled, "Aconitum japonicum Thunb". Two hours after arrival, VA-ECMO was initiated as circulatory collapse became refractory to antiarrhythmics and vasopressors. Nine hours after arrival, an electrocardiogram revealed a return to sinus rhythm. The patient was weaned off VA-ECMO and the ventilator on hospital days 3 and 5, respectively. On hospital day 15, he was transferred to a psychiatric hospital. The other half of the root and his biological samples were toxicologically analyzed using LC-MS/MS, revealing 244.3 mg/kg of aconitine and 24.7 mg/kg of mesaconitine in the root. Serum on admission contained 1.50 ng/mL of aconitine. Beyond hospital day 2, neither were detected. Urine on admission showed 149.09 ng/mL of aconitine and 3.59 ng/mL of mesaconitine, but these rapidly decreased after hospital day 3. CONCLUSION: The key to saving the life of a patient with severe aconite poisoning is to introduce VA-ECMO as soon as possible.

Activation of microglia induces symptoms of Parkinson's disease in wild-type, but not in IL-1 knockout mice.

BACKGROUND: Parkinson's disease (PD) is an age-related progressive neurodegenerative disorder caused by selective loss of dopaminergic neurons from the substantia nigra (SN) to the striatum. The initial factor that triggers neurodegeneration is unknown; however, inflammation has been demonstrated to be significantly involved in the progression of PD. The present study was designed to investigate the role of the pro-inflammatory cytokine interleukin-1 (IL-1) in the activation of microglia and the decline of motor function using IL-1 knockout (KO) mice. METHODS: Lipopolysaccharide (LPS) was stereotaxically injected into the SN of mice brains as a single dose or a daily dose for 5 days (5 mg/2 ml/injection, bilaterally). Animal behavior was assessed with the rotarod test at 2 hr and 8, 15 and 22 days after the final LPS injection. RESULTS: LPS treatment induced the activation of microglia, as demonstrated by production of IL-1ß and tumor necrosis factor (TNF) α as well as a change in microglial morphology. The number of cells immunoreactive for 4-hydroxynonenal (4HNE) and nitrotyrosine (NT), which are markers for oxidative insults, increased in the SN, and impairment of motor function was observed after the subacute LPS treatment. Cell death and aggregation of α-synuclein were observed 21 and 30 days after the final LPS injection, respectively. Behavioral deficits were observed in wild-type and TNFα KO mice, but IL-1 KO mice behaved normally. Tyrosine hydroxylase (TH) gene expression was attenuated by LPS treatment in wild-type and TNFα KO mice but not in IL-1 KO mice. CONCLUSIONS: The subacute injection of LPS into the SN induces PD-like pathogenesis and symptoms in mice that mimic the progressive changes of PD including the aggregation of α-synuclein. LPS-induced dysfunction of motor performance was accompanied by the reduced gene expression of TH. These findings suggest that activation of microglia by LPS causes functional changes such as dopaminergic neuron attenuation in an IL-1-dependent manner, resulting in PD-like behavioral impairment.

Celecoxib reduces brain dopaminergic neuronaldysfunction, and improves sensorimotor behavioral performance in neonatal rats exposed to systemic lipopolysaccharide.

BACKGROUND: Cyclooxygenase-2 (COX-2) is induced in inflammatory cells in response to cytokines and pro-inflammatory molecules, suggesting that COX-2 has a role in the inflammatory process. The objective of the current study was to examine whether celecoxib, a selective COX-2 inhibitor, could ameliorate lipopolysaccharide (LPS)-induced brain inflammation, dopaminergic neuronal dysfunction and sensorimotor behavioral impairments. METHODS: Intraperitoneal (i.p.) injection of LPS (2 mg/kg) was performed in rat pups on postnatal Day 5 (P5), and celecoxib (20 mg/kg) or vehicle was administered (i.p.) five minutes after LPS injection. Sensorimotor behavioral tests were carried out 24 h after LPS exposure, and brain injury was examined on P6. RESULTS: Our results showed that LPS exposure resulted in impairment in sensorimotor behavioral performance and injury to brain dopaminergic neurons, as indicated by loss of tyrosine hydroxylase (TH) immunoreactivity, as well as decreases in mitochondria activity in the rat brain. LPS exposure also led to increases in the expression of α-synuclein and dopamine transporter proteins and enhanced [3H]dopamine uptake. Treatment with celecoxib significantly reduced LPS-induced sensorimotor behavioral disturbances and dopaminergic neuronal dysfunction. Celecoxib administration significantly attenuated LPS-induced increases in the numbers of activated microglia and astrocytes and in the concentration of IL-1ß in the neonatal rat brain. The protective effect of celecoxib was also associated with an attenuation of LPS-induced COX-2+ cells, which were double labeled with TH + (dopaminergic neuron) or glial fibrillary acidic protein (GFAP) + (astrocyte) cells. CONCLUSION: Systemic LPS administration induced brain inflammatory responses in neonatal rats; these inflammatory responses included induction of COX-2 expression in TH neurons and astrocytes. Application of the COX-2 inhibitor celecoxib after LPS treatment attenuated the inflammatory response and improved LPS-induced impairment, both biochemically and behaviorally.

Simulation-based risk assessment for the leakage of toxic substances in a chemical plant and the effects on the human body: ethanol as a working model.

Chemical plants must handle a wide variety of hazardous substances. To ensure safety in such plants, it is necessary to conduct extensive and highly accurate risk assessments. In this study, we aimed at developing a method that enables flexible and accurate risk assessment. We combined two different simulation tools to reproduce the phenomena of toxic gas leakage and diffusion as well as its impact on human health. The atmospheric diffusion after the leakage of toxic gas was simulated by computational fluid dynamics (CFD). Assuming the movement line of the person, toxic gas absorption and subsequent metabolism were calculated by a physiologically based pharmacokinetic (PBPK) model. From this, changes in blood concentration of toxic substances with time were simulated and we evaluated the effects of toxic gases on human body. Ethanol was selected as a toxic gas in this study. Based on the assumed scenario, the diffusion of leaked ethanol gas was calculated by CFD leading to the confirmation that the concentration of ethanol gas varies significantly with wind speed, human position, and elapsed time. The PBPK model showed that the maximum blood concentration of ethanol was 161 µmol/L, which is sufficiently low compared to that of ethanol poisoning (i.e., 10,900 µmol/L). These results suggest that the effects on the human body are relatively low and the evacuation can be performed safely. Compared to conventional methods of risk assessment, our new method allows the risk assessment of multiple scenarios, namely interindividual differences, activity status and the used of protective equipment.

Development of a risk assessment method for the detailed consideration of the effects of liquid toxic substance leakage incidents on the human body: ethanol as a model substance.

To ensure safety in chemical plants handling a wide variety of liquid and gaseous hazardous substances, it is necessary to carry out highly accurate risk assessments and take appropriate measures. In this study, a risk assessment method was developed for the problem of the leakage of liquid hazardous substances. The risk assessment of toxic liquid leaks must consider the exposure of workers to the liquid and toxic gases produced by vaporization. The absorption and subsequent metabolism of hazardous substances in the body via multiple pathways after exposure to liquids and gases was calculated using a pharmacokinetic model. Estimation of exposure concentrations of toxic gases volatilized from leaked liquids was reproduced by computational fluid dynamics simulation. In this study, ethanol was selected as the hazardous substance and the risk of hazardous liquid leakage was assessed. The results of the analysis, which considered liquid and gas exposure under the conditions of the assumed scenario, showed that the maximum blood concentration of ethanol was 1640 µmol/L, which is sufficiently low compared to the concentration of 10,900 µmol/L at which acute toxic effects become apparent. These results suggest that work can be carried out safely under the conditions of the assumed scenario. The risk assessment methodology for liquid spills in this study confirms that risk assessment is possible under multiple scenarios, including individual differences, activity conditions, and the use of protective equipment.

Noncanonical mechanism of Nrf2 activation by diacylglycerol polyethylene glycol adducts in normal human epidermal keratinocytes.

Polyethylene glycol-23 glyceryl distearate (GDS-23), a diacylglycerol polyethylene glycol adduct, forms niosomes with a liposome-like structure and functions as an active ingredient in drug delivery systems. In addition, it upregulates antioxidant proteins such as heme oxygenase 1 and NAD(P)H-quinone dehydrogenase 1 in cells. However, the activation of nuclear factor E2-related factor-2 (Nrf2), which plays a role in inducing the expression of antioxidant proteins, and its protective effects induced by GDS-23 treatment against oxidative stress have not been elucidated. This study aimed at verifying the activation of Nrf2 by GDS-23 and clarifying its underlying mechanisms, and investigated whether GDS-23 protects against hydroquinone-induced cytotoxicity. Normal human epidermal keratinocytes were treated with GDS-23. Real-time reverse transcription-polymerase chain reaction, western blotting, and immunostaining were used to investigate the mechanism of Nrf2 activation, and neutral red assay was performed to evaluate cytotoxicity. GDS-23-treated cells showed an increase in antioxidant protein levels and stabilization of Nrf2 in the nucleus. During Nrf2 activation, p62, an autophagy-related adaptor protein, was phosphorylated at Ser349. Inhibition of the interaction between the phosphorylated p62 and Kelch-like ECH-associated protein 1 significantly suppressed the GDS-23-mediated induction of antioxidant protein expression. In addition, hydroquinone-induced cell toxicity was significantly attenuated by GDS-23. GDS-23 induced the intracellular antioxidant system by activating Nrf2 in a p62 phosphorylation-dependent manner without generating oxidative stress in the cells. GDS-23 may be applied as a multifunctional material for drug delivery system that enhances internal antioxidant systems.

Urinary profiles of methoxyphenamine and its metabolite after inhalation of methoxyphenamine smoke in humans: aiming to distinguish between active and passive exposure.

PURPOSE: Methamphetamine (METH) is commonly abused through smoking. However, the lack of evidence regarding differences in urinary METH excretion after its active and passive inhalation has resulted in complications where the accused claims passive exposure. This study aimed to determine the differences in urinary excretion after active and passive inhalation of the drug, using methoxyphenamine (MPA) as a model for METH. METHODS: Body temperature and locomotor activity were measured in mice as indicators of central nervous system toxicity. Six healthy adult male subjects were exposed to passive or active inhalation of MPA smoke in a small room, and urine samples were taken. MPA concentrations were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: There were no signs of toxicity in mice exposed to MPA smoke, ensuring the safety of the clinical study. Urinary MPA concentrations were significantly lower with passive inhalation compared with those of active inhalation. The maximum urinary MPA concentration in passive inhalation was 13.4 ng/mL, which was 1/60 of active inhalation with 800 ng/mL. The urinary excretion in passive inhalation until 24 h was 8.21 µg, which was 1/76 of active inhalation with 625 µg. CONCLUSIONS: Since METH and MPA are expected to be excreted similarly, urinary METH concentrations in passively exposed persons are expected to be lower than the cutoff value of the screening kit. If the urine screening test is positive, the suspect should be considered a METH user. TRIAL REGISTRATION NUMBER: jRCTs031210604, registration date: Feb. 9, 2022.

Interleukin-6 regulates the expression of hepatic canalicular efflux drug transporters after cecal ligation and puncture-induced sepsis: A comparison with lipopolysaccharide treatment.

Hepatic multidrug transporters expressed on the canalicular membrane play a role in the hepatobiliary excretion of xenobiotics and endogenous substrates. The aim of this study was to elucidate the role of pro-inflammatory cytokines in the regulation of hepatic drug transporter expression after cecal ligation and puncture (CLP), a valuable tool for studying polymicrobial sepsis, and to compare CLP with lipopolysaccharide (LPS) treatment. CLP reduced the expression of Mdr2/Abcb4, Mrp2/Abcc2, Bsep/Abcb11, Bcrp/Abcg2, and Mate1/Slc47a1 mRNAs in wild-type (WT) mouse livers in a time-dependent manner up to 48 h postoperation. LPS also reduced the expression of all transporters in WT mouse livers 24 h posttreatment; thereafter, expression levels tended to return to normal by 48 h posttreatment. IL-6-/- mice exhibited inhibited downregulation of drug transporters following CLP, although IL-1-/- and TNFα-/- mice exhibited the reduced expression of all transporters in a manner similar to that found in WT mice. Compared with CLP, LPS treatment reduced the expression of all transporters in all cytokine-deficient mouse livers, except for the expression of Mrp2/Abcc2 in IL-6-/- mice. Overall, these findings suggest that IL-6 is major factor in the downregulation of hepatic multidrug transporters following the onset of polymicrobial sepsis but not after LPS treatment.

Downregulation of the gene expression of Cyp2c29 and Cyp3a11 by cecal ligation and puncture-induced sepsis is associated with interleukin-6.

Sepsis is a pathological condition that affects the metabolism of administered drugs, leading to changes in the duration and intensity of their intended efficacies. Proinflammatory cytokines downregulate the expression of cytochrome P450s (P450s). The effects of P450 expression under inflammatory conditions have been studied using prophlogistic substances such as lipopolysaccharide; however, few studies have focused on clinical models of sepsis. Here, we show that cecal ligation and puncture (CLP), an approach for the study of human polymicrobial sepsis, leads to the expression of interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor α (TNFα) at 24 h after the CLP operation. Following CLP, IL-6-/- mice exhibited markedly lower survival than WT mice. In addition, CLP led to the significant downregulation of Cyp2c29 and Cyp3a11 gene expression in IL-1α-/-/ß-/- (IL-1-/-) and TNFα-/- mice as well as in WT mice. In contrast, CLP elicited no significant effect on Cyp3a11 expression in IL-6-/- mice. Although CLP reduced the Cyp2c29 expression level in IL-6-/- mice, the expression of Cyp2c29 was lower in CLP-operated WT mice than in CLP-operated IL-6-/- mice. The reduction in the respective P450 protein levels and activities due to CLP-induced sepsis, reflected in the mRNA expression levels, was abolished by IL-6 depletion. Thus, CLP-induced sepsis downregulates P450 gene expression, particularly Cyp2c expression, and this effect is associated with IL-6 without affecting resistance to CLP-induced sepsis. These findings demonstrate the usefulness of CLP for studying the regulation of P450s and highlight IL-6 as a potential indicator of drug-metabolizing capacity under septic conditions.

Toxicity manifestations and sex differences due to MARTA olanzapine.

Olanzapine is widely used as a treatment for schizophrenia and other psychiatric disorders. Its metabolic side effects, including weight gain and hyperglycemia, are a clinical problem; however, their full mechanism is not yet clearly understood. Recently, it was reported that the accumulation of oxidative stress in the hypothalamus may cause obesity and diabetes mellitus. Epidemiologically, metabolic side effects are known to be more likely to occur in women. In the present study, we investigated and tested the hypothesis that olanzapine induces oxidative stress in the hypothalamus and induces metabolic side effects. We also examined its association with sex differences. Olanzapine was administered intraperitoneally to male and female C57BL/6 mice, and the expression levels of oxidative stress-responsible genes in the hypothalamus and cerebral cortex were measured by qRT-PCR. In addition, olanzapine was administered intraperitoneally to C57BL/6 and Nrf2 KO mice, and the expression level of total glutathione was measured. Gene expressions induced by the Keap1-Nrf2-regulated system showed different responses to olanzapine for each gene. Under the conditions of this experiment, cystine-glutamate transporter was decreased although heme oxygenase-1 and γ-glutamylcysteine synthetase were increased. It was also clear that these responses were not hypothalamus-specific. Long-term feeding with olanzapine suppressed weight gain in males but not females. No glucose intolerance was observed at 13 weeks of administration. Furthermore, deaths occurred only in females. In conclusion, this study failed to provide evidence that olanzapine induces oxidative stress in a hypothalamic-specific manner. Instead, sex differences were observed in response to long-term and high-dose olanzapine administration, suggesting that individual susceptibility to olanzapine toxicity occurred in female mice.

Possible involvement of transient receptor potential channels in electrophile-induced insulin secretion from RINm5F cells.

Endogenously produced reactive oxygen species reportedly stimulate insulin secretion from islet ß-cells. However, the molecular machinery that governs the oxidant-induced insulin secretion has yet to be determined. The present study demonstrates, using rat islet ß-cell-derived RINm5F cells, the involvement of the transient receptor potential (TRP) cation channels in the insulin secretion induced by the lipid peroxidation product 4-hydroxy-2-nonenal. Short-term (1 h) exposure of 4-hydroxy-2-nonenal induced a transient increase in intracellular Ca(2+) concentration and subsequent insulin secretion in a concentration-dependent manner. The increase in intracellular Ca(2+) concentration seemed to be due to an influx through the L-type voltage-dependent Ca(2+) channel, since it was not observed when extracellular Ca(2+) was absent and was inhibited almost completely by diltiazem or nifedipine. Ruthenium red, a non-specific inhibitor of TRP channels, inhibited the Ca(2+) influx and insulin secretion evoked by 4-hydroxy-2-nonenal. Among the TRP channels, TRPA1 was found to be predominantly expressed, not only in RINm5F cells, but also rat islets. TRPA1 agonists, allylisothiocyanate and 15-deoxy-Δ(12,14)-prostaglandin J(2), significantly induced Ca(2+) influx, and a specific inhibitor TRPA1, HC-030031, blocked the effects elicited by 4-hydroxy-2-nonenal. These results suggest that 4-hydroxy-2-nonenal induces Ca(2+) influx via the activation of TRP channels, including TRPA1, which appears to be coupled with the L-type voltage-dependent Ca(2+) channel, and ultimately insulin secretion in RINm5F cells.

Toxicokinetic evaluation during intoxication of psychotropic drugs using brain microdialysis in mice.

In the event of an overdose, the pharmacokinetics of the drug may be altered, resulting in an unexpectedly rapid increase in blood and tissue drug concentrations. Because central nervous system (CNS)-acting drugs are the major cause of hospitalization for overdose, brain concentrations, which are closely related to the development of acute psychotropic symptoms, would be important. However, due to the lack of an appropriate model for overdose, it is difficult to predict the CNS symptoms of patients with acute poisoning. To clarify the toxicokinetics during intoxication with CNS-acting drugs, we investigated the relationship between the dose and concentrations in the blood and brain in mice. Therapeutic or toxic doses of phenobarbital, flunitrazepam, imipramine, and amoxapine were administered intraperitoneally to mice. Serum and extracellular fluid of the brain were collected up to 24 hr after administration and analyzed using LC-MS/MS to determine the pharmacokinetic parameters in the serum and brain. A comparison of the four psychotropic drugs showed that the toxicokinetics of amoxapine in the blood and brain are clearly different from others, with the brain concentrations being specifically highly susceptible to increase during dose escalation. These results are consistent with the CNS-related symptoms observed in amoxapine overdose. Therefore, the methodology of the current study could be useful for predicting CNS toxicity during psychotropic drug poisoning.

Irinotecan-induced severe hypotension in a patient with lung cancer.

Most hypotension during chemotherapy is caused by an allergic mechanism. Conversely, non-allergic hypotension due to chemotherapy is rare. In this case report, we present a patient who suffered severe hypotension followed by the administration of irinotecan-based chemotherapy and some supportive care such as steroids for preventing emesis. A 71-year-old man with hypertension was diagnosed with stage IV small cell lung cancer (sT1cN3M0). Severe hypotension occurred in the patient after every administration of chemotherapy. Finally, he was able to receive all four courses of chemotherapy as planned along with the medical staff's support care. This case provides that a regimen that contained irinotecan and steroid could cause hypotension and the mechanism is partially explained by inhibiting choline esterase and adrenal insufficiency. We should be careful about non-allergic hypotension when we administer irinotecan-based chemotherapy.

Derivatization-assisted immunoassays: application for group-specific detection of potent methamphetamine and amphetamine enantiomers.

Reliable and feasible tools for detecting (S)-methamphetamine [(S)-MAP] and (S)-amphetamine [(S)-AP] are required for regulating their illicit circulation. Antibodies that react equally to these stimulants are desirable for this purpose, but have been difficult to generate because of the crucial difference between their characteristic structures: i.e., N-methylamino (MAP) and amino (AP) groups. Furthermore, their small molecular masses (Mr < 150) have hampered the generation of high-affinity antibodies. To overcome these problems, we converted (S)-MAP and -AP into their 2-(trimethylsilyl)ethyl carbamate forms, Teoc-(S)-MAP and -AP, respectively, as surrogate analytes. The Teoc-derivatization not only increases their molecular masses, but also masks their structural differences. We generated a novel monoclonal antibody that showed a satisfactory affinity to Teoc-(S)-MAP residues (Kd = 13 nM as the IgG form) and developed a competitive enzyme-linked immunosorbent assay (ELISA) using microplates containing immobilized Teoc-(S)-MAP residues. Almost overlapping dose-response curves were obtained for Teoc-(S)-MAP and -AP, with the limit of detection of 0.078 and 0.10 ng per assay, respectively. A fixed amount of test powder sample (1 mg) was derivatized with Teoc-O-succinimidyl for 5 min, and subjected to ELISA using Teoc-(S)-MAP as the calibration standard. Under this protocol, (S)-MAP and -AP were converted to their Teoc derivatives with 30% and 34% yield, respectively, determined using ELISA as "Teoc-(S)-MAP equivalent," being distinguished from the derivatization products of (R)-MAP, (R)-AP, ephedrine, (S)-methylenedioxymethamphetamine, tyramine, dopamine, and ß-alanine. This ELISA detected as little as 10 µg of (S)-MAP and -AP, and (S)-MAP in urine obtained from (S)-MAP-administered rats. Immunochromatography devices were also developed using gold nanoparticles coated with the monoclonal antibody, with which 0.10 mg of (S)-MAP and -AP was detected by the naked eye. We conclude that the present derivatization-assisted immunoassays may be useful for the detection of (S)-MAP and/or -AP in early stage screening of suspicious substances.