Variable temperature-nuclear magnetic resonance experiment and high-resolution MS/MSn measurement of hydroxycarbodenafil, and its PDE5 inhibitory activity

Hydroxycarbodenafil, an analogue of carbodenafil, was detected in a dietary supplement in China in 2020. However, previous reports have not identified some carbon signals from the piperazine ring in nuclear magnetic resonance (NMR) experiments. Because the compound contains an amide bond, the reaction was suggested to be characteristic of compounds with rotational isomers. Variable-temperature NMR is used to determine the rotational barrier between different conformations by changing the measurement temperature. Using this technique, we succeeded in obtaining the first distinct data, including the carbon signals of the piperazine ring in the NMR spectrum of hydroxycarbodenafil. We also confirmed that this technique could be applied to other carbodenafil analogues. Multi-stage mass spectrometry (MSn) measurements with a high-resolution mass spectrometer specific to the substructures were performed to develop a protocol for the structural determination of the carbodenafil analogues. In addition, hydroxycarbodenafil was analysed using X-ray crystallography, and its inhibitory activity against phosphodiesterase type 5 (PDE5) was measured. The IC50 value of the inhibitory activity of hydroxycarbodenafil for PDE5A1, a PDE5 isoform, of 2.9 nM was lower than the 4.5 nM for sildenafil, a positive control.

The biological effects and thermal degradation of NPB-22, a synthetic cannabinoid

PURPOSE

NPB-22 (quinolin-8-yl 1-pentyl-1H-indazole-3-carboxylate), Adamantyl-THPINACA (N-(1-adamantantyl)-1-[(tetrahydro-2H-pyran-4-yl)methyl]-1H-indazole-3-carboxamide), and CUMYL-4CN-B7AICA (1-(4-cyanobutyl)-N-(2-phenylpropan-2-yl)-1H- pyrrolo[2,3-b]pyridine-3-carboxamide), synthetic cannabinoids were evaluated in terms of CB1 (cannabinoid receptor type 1) and CB2 (cannabinoid receptor type 2) activities, and their biological effects when inhaled similar to cigarettes were examined.

METHODS

The half maximal effective concentration values of the aforementioned synthetic cannabinoids at the CB1 and CB2 were investigated using [35S]guanosine-5'-O-(3-thio)-triphosphate binding assays. In addition, their biological effects were evaluated using the inhalation exposure test with mice. The smoke generated was recovered by organic solvents in the midget impingers, and the thermal degradation compounds of the smoke components were identified and quantified using a liquid chromatography-photo diode array detector.

RESULTS

NPB-22 and Adamantyl-THPINACA had equivalent CB1 activity in in vitro assays. Meanwhile, NPB-22 had a weaker biological effect on some items on the inhalation exposure test than Adamantyl-THPINACA. When analyzing organic solvents in the midget impingers, it was revealed that NPB-22 was degraded to 8-quinolinol and pentyl indazole 3-carboxylic acid by combustion. In addition, these degradation compounds did not have CB1 activity.

CONCLUSION

It was estimated that the biological effects of NPB-22 on the inhalation exposure test weakened because it underwent thermal degradation by combustion, and the resultant degradation compounds did not have any CB1 activity in vitro.

Reproductive and neurobehavioral effects of dinotefuran in an F1 -generation toxicity study in mice

BACKGROUND

Few studies were found for neurobehavioral toxicity of dinotefuran in mammals. This study was designed to evaluate the reproductive and neurobehavioral effects of dinotefuran exposure in mice.

METHODS

Dinotefuran was given in the diet to provide levels of 0% (control), 0.015%, 0.03%, and 0.06% from 5 weeks of age of the F0 generation to 11 weeks of age of the F1 generation in mice. Selected reproductive and neurobehavioral parameters were measured.

RESULTS

Movement time increased with a significant dose-related trend, and the related variables of rearing time decreased in significant dose-related trends in adult males in the F0 generation. Litter size and weight increased in significant dose-related trends, and sex ratio decreased in a significant dose-related trend. The average body weight of offspring increased in a significant dose-related trend on postnatal day (PND) 21 in both sexes. In the olfactory orientation on PND 14 in female offspring, the time required lengthened in a significant dose-related trend. In male offspring, total distance and the average speed decreased in significant dose-related trends, and the average time of rearing, number of defecations, and frequencies of mice with urination increased in a significant dose-related trend. In female offspring, the related variables of rearing increased in significant dose-related trends. In spontaneous behavior of males, the parallel lines during the control and treatment groups indicated a significant distance in the number of horizontal activities.

CONCLUSIONS

The dose levels of dinotefuran in the present study produced several adverse effects on reproductive and neurobehavioral parameters in mice.

Stability assessment and content determination test of oral liquid forms of beclomethasone dipropionate prepared in hospital pharmacy

OBJECTIVES

Oral beclomethasone dipropionate (BDP) is known for its use as a therapeutic medicine for gastrointestinal graft-versus-host disease (GI-GVHD). Despite growing demand for oral BDP formulation, no commercial forms have yet been marketed. Therefore, at the Tokyo Metropolitan Cancer and Infectious Disease Centre Komagome Hospital, pharmacists prepare oral liquid forms of BDP for patients with upper GI-GVHD. This study aims to develop a new high performance liquid chromatography (HPLC) method for measuring BDP in the prepared formulations and assessing its quality.

METHODS

We developed a new HPLC method for measuring BDP in prepared formulations validated according to international guidelines. Three types of formulations were prepared and analysed using the validated HPLC method. One contains 1 mg of BDP per 30 mL aqueous solution, and the others using ethanol for preparation contain 1 mg of BDP per 15 mL aqueous solution. For stability assessment, the BDP contents were assayed while formulations were stored in plastic bottles for 8 weeks under two different conditions of 25°C in bright light and 4°C in darkness. A content determination test was also conducted to assess the individual contents of BDP and lot-to-lot variation in dosage units.

RESULTS

A stability test demonstrated that the remaining BDP content after the storage period was greater than 90% of the initial content in almost all samples regardless of storage conditions. A content determination test showed thattwo new ethanol-containing formulations contained about 0.1 mg more BDP than the original ethanol-free formulation and it was close to the target BDP content of 1 mg. Furthermore, new formulations had less lot-to-lot BDP variation in dosage units than the original formulation.

CONCLUSIONS

A new HPLC method for measuring BDP in prepared formulations was developed and validated. The results of the stability test and content determination test indicated that the newly designed formulations were superior to the conventional formulation.

Time-Course of Transcriptomic Change in the Lungs of F344 Rats Repeatedly Exposed to a Multiwalled Carbon Nanotube in a 2-Year Test

Despite intensive toxicological studies of carbon nanotubes (CNTs) over the last two decades, only a few studies have demonstrated their pulmonary carcinogenicities in chronic animal experiments, and the underlying molecular mechanisms are still unclear. To obtain molecular insights into CNT-induced lung carcinogenicity, we performed a transcriptomic analysis using a set of lung tissues collected from rats in a 2-year study, in which lung tumors were induced by repeated intratracheal instillations of a multiwalled carbon nanotube, MWNT-7. The RNA-seq-based transcriptome identified a large number of significantly differentially expressed genes at Year 0.5, Year 1, and Year 2. Ingenuity Pathway Analysis revealed that macrophage-elicited signaling pathways such as phagocytosis, acute phase response, and Toll-like receptor signaling were activated throughout the experimental period. At Year 2, cancer-related pathways including ERBB signaling and some axonal guidance signaling pathways such as EphB4 signaling were perturbed. qRT-PCR and immunohistochemistry indicated that several key molecules such as Osteopontin/Spp1, Hmox1, Mmp12, and ERBB2 were markedly altered and/or localized in the preneoplastic lesions, suggesting their participation in the induction of lung cancer. Our findings support a scenario of inflammation-induced carcinogenesis and contribute to a better understanding of the molecular mechanism of MWCNT carcinogenicity.

Analytical characterization and differentiation between threo- and erythro-4-fluoroethylphenidate

PURPOSE

Methylphenidate analogs appeared on the drug market during the last years. Its analogs contain two chiral centers and, thus, have potential varying configurations (i.e., threo and erythro forms). This study presents the analytical characterization of 4-fluoroethylphenidate (4-FEP) and its differentiation between threo- and erythro-4-FEP.

METHODS

Analysis of the samples included high-performance liquid chromatography (HPLC), gas chromatography-electron ionization-mass spectrometry (GC-EI-MS), high-resolution mass spectrometry (HRMS) analyses, nuclear magnetic resonance (NMR) spectroscopy and X-ray crystal structure analysis.

RESULTS

NMR spectroscopic investigations confirmed the differences between threo- and erythro-4-FEP, and demonstrated that both isomers could be separated using HPLC and GC methods. Two samples obtained from one vendor in 2019 consisted of threo-4-FEP, whereas the other two samples obtained from a different vendor in 2020 consisted of a mixture of threo- and erythro-4-FEP.

CONCLUSIONS

Several analytical approaches including HPLC, GC-EI-MS, HRMS analyses, NMR spectroscopy and X-ray crystal structure analysis enabled the unambiguous identification of threo- and erythro-4-FEP. The analytical data presented in this article will be useful for identifying threo- and erythro-4-FEP included in illicit products.

Cytotoxic effects of psychoactive isobutyrylfentanyl and its halogenated derivatives on isolated rat hepatocytes

The novel and numerous psychoactive compounds derived from the analgesic prescription drug N-phenyl-N-[1-(2-phenylethyl)piperidin-4-yl]propanamide (fentanyl) have been illegally abused as recreational drugs and caused numerous fatalities. Because some psychoactive/psychotropic drugs are known to be hepatotoxic in humans and experimental animals, the cytotoxic effects and mechanisms of 4-fluoroisobutyrylfentanyl (4F-iBF), 4-chloroisobutyrylfentanyl (4Cl-iBF), and the parent compound isobutyrylfentanyl (iBF) were studied in freshly isolated rat hepatocytes. 4F-iBF caused not only concentration (0-2.0 mM)- and time (0-3 h)-dependent cell death accompanied by the depletion of cellular ATP and reduced glutathione (GSH) and protein thiol levels but also the accumulation of oxidized glutathione. Of these fentanyls examined, 4Cl-iBF/4F-iBF-induced cytotoxicity with the loss of mitochondrial membrane potential at concentrations of 0.5 and 1.0 mM and the production of reactive oxygen species (ROS) at 0.5 mM were greater than those induced by iBF. The pretreatment of hepatocytes with N-acetyl-l-cysteine as a precursor of cellular GSH ameliorated, at least in part, cytotoxicity accompanied by insufficient ATP levels, the loss of mitochondrial membrane potential, and generation of ROS caused by 4Cl-iBF/4F-iBF, whereas pretreatment with diethyl maleate as a GSH depletor enhanced fentanyl-induced cytotoxicity accompanied by the rapid loss of cellular GSH. Taken collectively, these results indicate that the onset of cytotoxic effects caused by these fentanyls is partially attributable to cellular energy stress as well as oxidative stress.

Development of a detector tube for screening tadalafil and its analogues in adulterated sexual enhancement products

Sexual enhancement products adulterated with phosphodiesterase 5 inhibitors (PDE-5i) pose a serious public health concern. Tadalafil and its analogues (Tds) are PDE-5i frequently detected as adulterants. In this study, a Td detector tube for the rapid detection of Tds was developed based on the color change reaction between sulfuric acid and Tds. The specificity of this test method was evaluated using 13 Tds, all of which elicited positive results. Additionally, 30 commonly found adulterants in dietary supplements, 11 active pharmaceutical ingredients of psychotropic drugs and 18 food ingredients were tested and obtained no false-positive results, except levomepromazine. The test tube accurately detected the presence or absence of Tds in 54 commercially available products. The visual detection limit was 2-50 and 5-20 μg/ml for Tds and tadalafil-spiked samples with matrix, respectively. The applicability of the developed detector tube to a semiquantitative test using digital image analyses were investigated using red, green, and blue color values. The results of the recovery test suggested that the tube test was affected by the dark-colored matrix. The results of semiquantitative analyses of tadalafil for five marketed products were consistent with the liquid chromatographic quantification results, except for the blue value. The detector tube developed in this study can facilitate with the rapid screening of Tds in adulterated sexual enhancement products.

Continuous infiltration of small peritoneal macrophages in the mouse peritoneum through CCR2-dependent and -independent routes during fibrosis and mesothelioma development induced by a multiwalled carbon nanotube, MWNT-7

Although toxicities of multiwalled carbon nanotube (MWCNT) have been found to be related with activities of macrophages phagocytosing the fibers, the exact relationship between macrophage population and pathogenesis of fibrosis and mesotheliomas induced by MWCNTs is largely unknown. CCL2-CCR2 axis, a major monocyte/macrophage infiltration route, is thought to be involved in not only acute inflammation but also the formation of tumor microenvironment. We therefore described a time-course of alteration of macrophage population in an attempt to clarify the contribution of the Ccr2 gene to mesotheliomagenesis. Wild-type (WT) C57BL/6 mice and Ccr2-knockout (KO) mice were intraperitoneally administered with MWNT-7 and were sequentially necropsied at 1, 7, 28, 90, and 245 day(s) after the injection. Peritoneal fibrosis was prominent in all MWCNT-treated mice, with a lower severity in the KO mice. No differences were observed in the incidences of neoplastic lesions of mesothelia between WT and KO mice. A flow cytometric analysis revealed that after gross disappearance of macrophages after MWCNT exposure, small peritoneal macrophages (SPMs) were exclusively refurbished by the CCR2-dependent route at day 1 (as Ly-6C+MHC class II- cells), followed by additional CCR2-independent routes (as Ly-6C-MHC class II- cells); i.e., the only route in KO mice; with a delay of 1-7 days. The SPMs derived from both routes appeared to differentiate into maturated cells as Ly-6C-MHC class II+, whose ratio increased in a time-dependent manner among the total SPM population. Additionally, most macrophages expressed M1-like features, but a small fraction of macrophages exhibited an M1/M2 mixed status in MWCNT-treated animals. Our findings demonstrate a long-persistent activation of the CCL2-CCR2 axis after MWCNT exposure and enable a better understanding of the participation and potential roles of SPMs in fibrous material-induced chronic toxicities.

Hepatic and renal toxicities and metabolism of fentanyl analogues in rats

New synthetic opioids continue to emerge in the illicit market, and among them, fentanyl analogues pose a serious threat to the public health with their abuse and trafficking. We investigated the toxicity of fentanyl analogues on the liver and kidneys mediated by the µ-opioid receptor (MOR). Our study focused on 4-fluoro-isobutyrylfentanyl (4F-iBF), which is classified as a "narcotic" in Japan; structurally similar analogues 4-chloro-isobutyrylfentanyl (4Cl-iBF) and isobutyrylfentanyl (iBF) were also investigated. Rats that were intraperitoneally administered 4F-iBF (5 mg/kg (12.3 μmol/kg)) or iBF (12.3 μmol/kg) displayed hepatic and renal ischemic-like damage, but 4Cl-iBF (12.3 μmol/kg) did milder renal damage only. We found that the agonist activity of 4F-iBF, at MORs was approximately 7.2 times that of 4Cl-iBF, and that pretreatment with MOR antagonist naltrexone (0.8 mg/kg) alleviated liver and kidney injuries caused by 4F-iBF. These results suggested that 4F-iBF might cause ischemic damage to the liver and kidneys, induced by respiratory depression mediated by MORs. Furthermore, to elucidate the metabolism of fentanyl analogues, we investigated the change over time in the amount of 4F-iBF, 4Cl-iBF, iBF (6.15 μmol/kg, respectively), and their respective metabolites in serum after intraperitoneal administration to rats. The results showed that in 24-h post-dose serum, 4Cl-iBF and iBF were substantially eliminated while 4F-iBF remained at about 30% of the maximum level, and each of the N-dephenylethylated metabolites of 4F-iBF, 4Cl-iBF, and iBF was detected in 2-h post-dose serum. The results from this study revealed information on the hepatic and renal toxicities and metabolism related to fentanyl analogues.

[Improvement Method of Confirmation Test of the In-pharmacy Formulation as Topical Medicine No. 37-①]

Topical Medicine No. 37-① is one of the in-pharmacy formulation that specifies a confirmation test (referred hereafter as the conventional method) to identify its ingredient diphenhydramine (DH) by colorimetric test. However, the conventional method is environmentally unfriendly due to the large amount of sample and organic solvent used, and the extraction process is complicated. We therefore developed three methods in view of improving the currently confirmation testing process: a simplified version of the conventional method, a TLC method, and an LC/photodiode array detector (PDA) method. The LC/PDA method was also examined for the quantitation of DH in order to determine its content in the medicine when needed. The LC/PDA method also demonstrated sufficient linearity in the calibration curve and recovery rate. We also evaluated whether the three methods developed in this study could be applied to Topical Medicine No. 37-①, which is made of absorptive cream containing different parabens.

Two-year intermittent exposure of a multiwalled carbon nanotube by intratracheal instillation induces lung tumors and pleural mesotheliomas in F344 rats

BACKGROUND

A mounting number of studies have been documenting the carcinogenic potential of multiwalled carbon nanotubes (MWCNTs); however, only a few studies have evaluated the pulmonary carcinogenicity of MWCNTs in vivo. A 2-year inhalation study demonstrated that MWNT-7, a widely used MWCNT, was a pulmonary carcinogen in rats. In another 2-year study, rats administered MWNT-7 by intratracheal instillation at the beginning of the experimental period developed pleural mesotheliomas but not lung tumors. To obtain data more comparable with rats exposed to MWNT-7 by inhalation, we administered MWNT-7 to F344 rats by intratracheal instillation once every 4-weeks over the course of 2 years at 0, 0.125, and 0.5 mg/kg body weight, allowing lung burdens of MWNT-7 to increase over the entire experimental period, similar to the inhalation study.

RESULTS

Absolute and relative lung weights were significantly elevated in both MWNT-7-treated groups. Dose- and time-dependent toxic effects in the lung and pleura, such as inflammatory, fibrotic, and hyperplastic lesions, were found in both treated groups. The incidences of lung carcinomas, lung adenomas, and pleural mesotheliomas were significantly increased in the high-dose group compared with the control group. The pleural mesotheliomas developed mainly at the mediastinum. No MWNT-7-related neoplastic lesions were noted in the other organs. Cytological and biochemical parameters of the bronchoalveolar lavage fluid (BALF) were elevated in both treated groups. The lung burden of MWNT-7 was dose- and time-dependent, and at the terminal necropsy, the average value was 0.9 and 3.6 mg/lung in the low-dose and high-dose groups, respectively. The number of fibers in the pleural cavity was also dose- and time-dependent.

CONCLUSIONS

Repeated administration of MWNT-7 by intratracheal instillation over the 2 years indicates that MWNT-7 is carcinogenic to both the lung and pleura of rats, which differs from the results of the 2 carcinogenicity tests by inhalation or intratracheal instillation.

Combined effects of maternal exposure to fungicides on behavioral development in F1 -generation mice: 3. Fixed-dose study of imazalil

BACKGROUND

Few published studies are reported for the neurobehavioral toxicity of combined exposure to fungicides in mammals. This study was aimed to re-evaluate the reproductive and neurobehavioral effects of maternal exposure to combined imazalil (IMZ) and thiabendazole (TBZ) with fixed-dose of IMZ in mice.

METHODS

IMZ/TBZ was given in the diet to provide levels of 0%/0% (control), 0.006%/0.006% (IMZ/TBZ), 0.006%/0.018%, and 0.006%/0.054% during the gestation and lactation periods. Selected reproductive and neurobehavioral parameters were measured in the F₁ generation.

RESULTS

No adverse effect of IMZ/TBZ was observed in litter size, litter weight, or sex ratio at birth. Concerning behavioral developmental parameters, the time required of olfactory orientation was accelerated significantly in higher-dose groups in female offspring on postnatal day 14 in a dose-related manner. Exploratory behavior examination indicated that the frequency of mice with urination increased in a significantly dose-related manner in male offspring. After weaning, any variables of exploratory behavior indicated no significant effects in both sexes of adult mice in the F₁ generation. In spontaneous behavior, the longitudinal pattern of total distance was not parallel (different pattern) among the control and IMZ/TBZ treatment groups in adult males.

CONCLUSIONS

The results from these series of combined exposure studies of IMZ/TBZ suggest that the main effects on exploratory and spontaneous behavior of adult mice in the F₁ generation after finishing chemical administration have been caused by the IMZ concentration of maternal exposure, with TBZ's effects being complementary.

Iron oxide nanoparticles exert inhibitory effects on N-Bis(2-hydroxypropyl)nitrosamine (DHPN)-induced lung tumorigenesis in rats

Iron oxide nanoparticles (magnetite) have been widely used in industry and medicine. However, the safety assessment of magnetite has not been fully completed. The present study was conducted to assess effects of magnetite on carcinogenic activity, using a medium-term bioassay protocol. A total of 100 male Fischer 344 rats, 6 weeks old, were randomly divided into 5 groups of 20 animals each, and given a basal diet and drinking water containing 0 or 0.1% of N-bis(2-hydroxypropyl)nitrosamine (DHPN) for 2 weeks. Two weeks later, the rats were intratracheally instilled magnetite 7 times at an interval of 4 weeks, at the doses of 0, 1.0 or 5.0 mg/kg body weight, and sacrificed at the end of the experimental period of 30 weeks. The multiplicities of macroscopic lung nodules and histopathologically diagnosed bronchiolo-alveolar hyperplasia, induced by DHPN, were both significantly decreased by the high dose of magnetite. The expression of minichromosome maintenance (MCM) protein 7 in non-tumoral alveolar epithelial cells, and the number of CD163-positive macrophages in tumor nodules were both significantly reduced by magnetite. It is suggested that magnetite exerts inhibitory effects against DHPN-induced lung tumorigenesis, by the reduction of alveolar epithelial proliferation and the M2 polarization of tumor-associated macrophages.

A case of spontaneous Zymbal's gland carcinoma with lung metastasis in an aged Fischer 344 rat

Zymbal’s gland neoplasms are induced in rats through the administration of various carcinogens, but spontaneous neoplasia is rare. This report describes a spontaneous Zymbal’s gland carcinoma with lung metastasis found in an aged male Fischer 344 rat. Macroscopically, the dome-like tumor nodule, approximately 30 mm in diameter with ulceration, was located near the ear canal of the rat. No healthy tissue or structure of Zymbal’s gland was identified on the corresponding side, while the normal salivary glands and a lacrimal gland were observed. Histologically, a large part of the tumor mass was occupied by poorly differentiated neoplastic cells, the shapes of which were oval to polygonal or fusiform. Additionally, clusters of sebaceous-like foamy cells and squamous metaplasia with prominent keratinization were observed. Tumor cells were found to metastasize to the lung; these cells displayed histological similarities, including a sebaceous gland-like pattern, to those in the primary site. The tumor cells were immunohistochemically positive for cytokeratin AE1/AE3 or vimentin but negative for CD68, S100, α-smooth muscle actin, von Willebrand factor, and desmin. Our results indicate that the tumor was a poorly differentiated Zymbal’s gland carcinoma with lung metastasis.

Histological sequence of the development of rat mesothelioma by MWCNT, with the involvement of apolipoproteins

A rat model of mesothelioma development by peritoneal injection of multiwalled carbon nanotube (MWCNT) has been established and found to be useful to understand the mechanisms underlying fibrous particles‐associated carcinogenesis. Its detailed histological sequence, however, remains largely obscure. We therefore aimed to assess the time‐course of mesothelioma development by MWCNT and evaluate a set of lipoprotein‐related molecules as potential mechanism‐based biomarkers for the phenomenon. Male Fischer 344 rats were injected intraperitoneally (ip) with MWCNT (MWNT‐7) at 1 mg/kg body weight, and necropsied at 8, 16, 24, 32, or 42 wk after injection. For biochemical analyses of the lipoprotein‐related molecules, more samples, including severe mesothelioma cases, were obtained from 2 other carcinogenicity tests. Histologically, in association with chronic inflammation, mesothelial proliferative lesions appeared at c. Wk‐24. Before and at the beginning of the tumor development, a prominent infiltration of CD163‐positive cells was seen near mesothelial cells. The histological pattern of early mesothelioma was not a papillary structure, but was a characteristic structure with a spherical appearance, composed of the mesothelioma cells in the surface area that were underlain by connective tissue‐like cells. Along with the progression, mesotheliomas started to show versatile histological subtypes. Serum levels of apolipoprotein A‐I and A‐IV, and a ratio of HDL cholesterol to total cholesterol were inversely correlated with mesothelioma severity. Overall, the detailed histological sequence of mesotheliomagenesis by MWCNT is demonstrated, and indicated that the altered profile of apolipoproteins may be involved in its underlying mechanisms.

Combined effects of maternal exposure to fungicides on behavioral development in F1 -generation mice: 2. Fixed-dose study of thiabendazole

BACKGROUND

Few published studies are reported for the neurobehavioral toxicity of combined exposure to fungicides in mammals. This study was aimed to re-evaluate the reproductive and neurobehavioral effects of maternal exposure to combined imazalil (IMZ) and thiabendazole (TBZ) with fixed-dose of TBZ in mice.

METHODS

IMZ/TBZ were given in the diet to provide levels of 0%/0% (control), 0.0015%/0.018% (IMZ/TBZ), 0.006%/0.018% and 0.024%/0.018% during the gestation and lactation periods. Selected reproductive and neurobehavioral parameters were measured in the F₁ generation.

RESULTS

No adverse effect of IMZ/TBZ was observed in litter size, litter weight, or sex ratio at birth. Concerning behavioral developmental parameters, the cliff avoidance on PND 7 of male offspring was restrained significantly in the treatment groups in a dose-related manner. Exploratory behavior examination indicated that the average time of rearing significantly lengthened in the high-dose group of male offspring. After weaning, the average time of rearing in exploratory behavior lengthened in a significant dose-related trend in adult females of the F₁ generation. Spontaneous behavior examination indicated that the average speed decreased significantly through 120 min in the high-dose group of the F₁ -generation males. In females, the average time of rearing lengthened significantly through 120 min in the high-dose group. In the longitudinal patterns, the parallel lines of the control and treatment groups indicated a significant distance in the average time of rearing in the F₁ -generation females.

CONCLUSIONS

The results from two combined exposure studies of IMZ/TBZ suggest that TBZ concentrations have caused major effects on exploratory and spontaneous behavior.

[Identification of Descarbonsildenafil in an Adulterated Dietary Supplement and Evaluation of Its Inhibitory Activity for Phosphodiesterase Type 5 (PDE5)]

Some illegal dietary supplements contain phosphodiesterase type 5 (PDE5) inhibitors, such as sildenafil, for exerting "therapeutic" effects in erectile dysfunction. This is apparently dangerous, and thus, should be appropriately regulated. Identification of descarbonsildenafil was first reported in Singapore in a coffee sample labeled to exert male sexual performance enhancement effects. However, it is unclear whether the compound possesses PDE5 inhibitory activity. We encountered during our survey of dietary supplements, a sexual enhancement product commercially available in Tokyo, in which a peak presumed to be of descarbonsildenafil was detected by LC-UV and electrospray ionization-tandem MS (ESI-MS/MS). The compound was isolated and identified as descarbonsildenafil with liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS), NMR, and X-ray crystal structural analysis. In addition, descarbonsildenafil showed PDE5 inhibitory activity in PDE5 inhibition assay, and its IC₅₀ value for PDE5A1 was found to be 30 nmol/L. The results of INADEQUATE NMR and X-ray crystal structural analysis in this study provide information for the identification of descarbonsildenafil. Since this study indicates that this compound is a PDE5 inhibitor having adequate activity, it is regulated as a drug component in Japan.

Combined effects of maternal exposure to fungicides on behavioral development in F1 -generation mice: 1. Several dose study of both imazalil and thiabendazole

BACKGROUND

Few published studies are reported for neurobehavioral toxicity of combined exposure to fungicides in mammals. This study was aimed to evaluate reproductive and neurobehavioral effects of maternal exposure to combined fungicides in mice.

METHODS

Imazalil (IMZ) and thiabendazole (TBZ) were given in the diet to provide levels of 0/0% (control), 0.0015/0.006% (IMZ/TBZ), 0.006/0.018%, and 0.024/0.054% during the gestation and lactation periods. Selected reproductive and neurobehavioral parameters were measured in the F₁ generation.

RESULTS

No adverse effect of IMZ/TBZ was observed in litter size, litter weight, or sex ratio at birth. The average body weight of male and female offspring was increased significantly in treatment groups during the lactation period. With respect to behavioral developmental parameters, the swimming head angle on PND 7 of male offspring was significantly accelerated in the treatment groups. After weaning, the movement time of exploratory behavior shortened in a significant dose-related manner in adult males of the F₁ generation. In adult females, the rearing time of exploratory behavior lengthened in a significant dose-related manner in the F₁ generation. Spontaneous behavior examination indicated that longitudinal patterns of each of the total distance and number of rearing were different during the control and treatment groups in the F₁ -generation females. Parallel width of the control and treatment groups was significantly different in the average time of movement and rearing in the F₁ -generation females.

CONCLUSIONS

The high-dose level of IMZ/TBZ in the present study produced several adverse effects in neurobehavioral parameters after weaning without concurrent chemical administration in mice.

A histopathological analysis of spontaneous neoplastic and non-neoplastic lesions in aged male RccHan:WIST rats

Histopathological information about spontaneous lesions in aged Hannover Wistar rats is limited. In this study, we describe spontaneous lesions found in 39 male RccHan:WIST rats used as a control in a carcinogenicity study. Neoplastic lesions were frequently seen in the endocrine system, such as pituitary adenomas in the pars distalis. This strain exhibited a high incidence of thymoma (10.3%), compared to other strains. We encountered an oligodendroglioma, a pituitary adenoma of the pars intermedia, and a prostate adenocarcinoma, which are comparatively rare in rats. While the variety and incidence of non-neoplastic lesions were similar to those in other strains, several interesting lesions occurred with relatively high incidence, including "harderianization" of the extraorbital lacrimal gland, common bile duct ectasia, and hyperplasia of pulmonary endocrine cells in the lung. Furthermore, comparative analyses demonstrated that the severity of chronic progressive nephropathy and murine progressive cardiomyopathy in RccHan:WIST rats was less than that in F344 rats.

Cytotoxic effects of thioxanthone derivatives as photoinitiators on isolated rat hepatocytes

Thioxanthone and its analogues, 2- or 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone (DETX) and xanthone, are used as photoinitiators of ultraviolet (UV) light-initiated curable inks. As these photoinitiators were found in numerous food/beverage products packaged in cartons printed with UV-cured inks, the cytotoxic effects and mechanisms of these compounds were studied in freshly isolated rat hepatocytes. The toxicity of DETX was greater than that of other compounds. DETX elicited not only concentration (0-2.0 mm)- and time (0-3 hours)-dependent cell death accompanied by the depletion of cellular adenosine triphosphate (ATP), and reduced glutathione (GSH) and protein thiol levels, but also the accumulation of GSH disulfide and malondialdehyde. Pretreatment of hepatocytes with either fructose at a concentration of 10 mm or N-acetyl-l-cysteine (NAC) at a concentration of 5.0 mm ameliorated DETX (1 mm)-induced cytotoxicity. Further, the exposure of hepatocytes to DETX resulted in the induction of reactive oxygen species (ROS) and loss of mitochondrial membrane potential, both of which were partially prevented by the addition of NAC. These results indicate that: (1) DETX-induced cytotoxicity is linked to mitochondrial failure and depletion of cellular GSH; (2) insufficient cellular ATP levels derived from mitochondrial dysfunction were, at least in part, ameliorated by the addition of fructose; and (3) GSH loss and/or ROS formation was prevented by NAC. Taken collectively, these results suggest that the onset of toxic effects caused by DETX may be partially attributable to cellular energy stress as well as oxidative stress.

Effects of piperonyl butoxide on exploratory behaviour in female mice

Previous studies reported that piperonyl butoxide (PBO) induces adverse effects on exploratory behaviour in male mice. However, no consistent effects of PBO treatment were observed in female mice. This study aimed to evaluate PBO’s neurobehavioral effects in female mice. Female mice were exposed to PBO through diet to provide levels of 0 (control), 0.025%, 0.1%, and 0.4% from 5 to 12 weeks of age, and selected behavioural parameters were measured. The average female body weight showed no significant effect from PBO treatment through the experimental periods. Regarding multiple-T water maze performance at 10 weeks of age, no significant effect caused by PBO treatment was observed. Exploratory behaviour examination of 8-week-old female mice indicated that the average speed declined in a significant dose-related manner, and the longitudinal pattern indicated a significant difference between the control and high-dose groups. For exploratory behaviour examination at 11 weeks of age, the total exploration distance shortened in a significant dose-related manner, and the average speed declined similarly. These longitudinal patterns showed significant differences between the control and high-dose groups. The PBO dose levels in this study produced several adverse effects on exploratory behaviour in female mice.

[Evaluation of the Cytotoxicity of Commercially Available Nail Adhesives]

Nail tips are nail art materials that can be attached to the nail with adhesives. Recently, nail/finger injuries related to nail tips have been reported and one of the causes is considered to be the adhesives used for attaching nail tips. The components of nail adhesives are mostly cyanoacrylate, which is also used as an industrial instant adhesive. During curing, cyanoacrylate adhesives release formaldehyde through hydrolysis. When it is marketed as a nail adhesive, there is no regulation regarding its formaldehyde amount nor obligation to indicate its ingredients in Japan. Additionally, a biological safety test is not required for nail adhesives. Thus, because the safety of nail adhesives is inadequately confirmed, it is necessary to investigate their biological safety. Therefore, we purchased 5 commercially available nail adhesives and 1 medical adhesive and examined their formaldehyde content and cytotoxicity. We examined the cytotoxicity of the adhesives in V79 cells by a colony forming assay. In this test, 5 nail adhesives showed higher toxicity than 1 medical adhesive. Formaldehyde concentrations in the extract of adhesives were as follows: 17.5 to 24.2 μg/mL for nail adhesives and 7.4 μg/mL for medical adhesives. Cyanoacetate did not elicit cytotoxicity at the final concentration up to 1000 μM. However, formaldehyde showed cytotoxicity, with an IC₅₀ of 79 μM (2.4 μg/mL). Taken together, the cytotoxicity of nail adhesives could be due to the formaldehyde generated by the hydrolysis of cyanoacrylate. It seems important that nail adhesives will be regulated by obligation and enhanced safety in the future.

Comparative study for carcinogenicity of 7 different multi-wall carbon nanotubes with different physicochemical characteristics by a single intraperitoneal injection in male Fischer 344 rats

The present study comparatively examined carcinogenicity of 7 different multi-wall carbon nanotubes (MWCNTs) with different physicochemical characteristics. Physicochemical characteristics of MWCNTs (referred to as M-, N-, WL-, SD1-, WS-, SD2- and T-CNTs in the present study) were determined using scanning electron and light microscopes and a collision type inductively coupled plasma mass spectrometer. Male Fischer 344 rats (10 weeks old, 15 animals per group) were administered MWCNTs at a single intraperitoneal dose of 1 mg/kg body weight, and sacrificed up to 52 weeks after the commencement. Fibers of M-, N-, WL- and SD1-CNTs were straight and acicular in shape, and contained few agglomerates. They were relatively long (38-59% of fibers were longer than 5 μm) and thick (33% to more than 70% of fibers were thicker than 60 nm). All of these 4 MWCNTs induced mesotheliomas at absolute incidences of 100%. Fibers of WS-, SD2- and T-CNTs were curled and tightly tangled to form frequent agglomerates. They were relatively short and thin (more than 90% of measured fibers were thinner than 50 nm). WS- CNT did not induce mesothelioma, and only one of 15 rat given SD2- or T-CNT developed tumor. Any correlations existed between the metal content and neither the size or form of fibers, nor the carcinogenicity. It is thus indicated that the physicochemical characteristics of MWCNTs are critical for their carcinogenicity. The straight and acicular shape without frequent agglomerates, and the relatively long and thick size, but not the iron content, may be critical factors. The present data can contribute to the risk management, practical use and social acceptance of MWCNTs.

Reproductive and neurobehavioral effects of maternal exposure to ethiprole in F1 -generation mice

BACKGROUND

Few published studies are reported for neurobehavioral toxicity of the phenylpyrazole insecticide ethiprole in mammals. This study was designed to evaluate the reproductive and neurobehavioral effects of maternal exposure to ethiprole in mice.

METHODS

Ethiprole was given in the diet to provide levels of 0 (control), 0.0002, 0.001, and 0.005% during the gestation and lactation periods. Selected reproductive and neurobehavioral parameters were measured in the F₁ generation.

RESULTS

No adverse effect of ethiprole was observed in litter size, litter weight, or sex ratio at birth. The average body weight of male and female offspring was increased significantly in treatment groups at postnatal day (PND) 21. With respect to behavioral developmental parameters, the time of olfactory orientation on PND 14 of male offspring was accelerated significantly in the high-dose group. For movement activity of exploratory behavior of female offspring in the F₁ generation, number of horizontal activities increased significantly in the high-dose group and the average speed declined significantly in all treatment groups. After weaning, the rearing time and the average time of rearing lengthened in a significant dose-related trend in adult males and females of the F₁ generation. Spontaneous behavior examination indicated that total distance and rearing time increased in the high-dose group, and number of horizontal activities and movement time decreased in a significant dose-related trend through 120 min in the F₁ -generation females.

CONCLUSIONS

The high-dose level of ethiprole in the present study produced several adverse effects in neurobehavioral parameters after weaning without administration in mice.

Preventive effects of fructose and N-acetyl-L-cysteine against cytotoxicity induced by the psychoactive compounds N-methyl-5-(2-aminopropyl)benzofuran and 3,4-methylenedioxy-N-methamphetamine in isolated rat hepatocytes

Psychoactive compounds, N-methyl-5-(2-aminopropyl)benzofuran (5-MAPB) and 3,4-methylenedioxy-N-methamphetamine (MDMA), are known to be hepatotoxic in humans and/or experimental animals. As previous studies suggested that these compounds elicited cytotoxicity via mitochondrial dysfunction and/or oxidative stress in rat hepatocytes, the protective effects of fructose and N-acetyl-l-cysteine (NAC) on 5-MAPB- and MDMA-induced toxicity were studied in rat hepatocytes. These drugs caused not only concentration-dependent (0-4 mm) and time-dependent (0-3 hours) cell death accompanied by the depletion of cellular levels of adenosine triphosphate (ATP) and glutathione (reduced form; GSH) but also an increase in the oxidized form of GSH. The toxic effects of 5-MAPB were greater than those of MDMA. Pretreatment of hepatocytes with either fructose at a concentration of 10 mm or NAC at a concentration of 2.5 mm prevented 5-MAPB-/MDMA-induced cytotoxicity. In addition, the exposure of hepatocytes to 5-MAPB/MDMA caused the loss of mitochondrial membrane potential, although the preventive effect of fructose was weaker than that of NAC. These results suggest that: (1) 5-MAPB-/MDMA-induced cytotoxicity is linked to mitochondrial failure and depletion of cellular GSH; (2) insufficient cellular ATP levels derived from mitochondrial dysfunction were ameliorated, at least in part, by the addition of fructose; and (3) GSH loss via oxidative stress was prevented by NAC. Taken collectively, these results indicate that the onset of toxic effects caused by 5-MAPB/MDMA may be partially attributable to cellular energy stress as well as oxidative stress.

Novel psychoactive benzofurans strongly increase extracellular serotonin level in mouse corpus striatum

We examined the effects of three benzofurans [1-(Benzofuran-5-yl)-N-methylpropan-2-amine (5-MAPB), 1-(Benzofuran-2-yl)-N-methylpropan-2-amine (2-MAPB), and 1-(Benzofuran-5-yl)-N-ethylpropan-2-amine (5-EAPB)] on the extracellular monoamine level in mouse corpus striatum by the microdialysis method and compared them with the effects of psychoactive 3,4-Methylenedioxymethamphetamine (MDMA). The effects of benzofurans on the extracellular monoamine level were qualitatively analogous to that of MDMA, with an increase in serotonin (5-HT) level exceeding dopamine (DA) level. The effects of 2-MAPB and 5-EAPB were almost the same as the effect of MDMA. However, 5-MAPB strongly increased extracellular monoamine level than MDMA. These differences in the potency appear to have a structure-activity relationship. The administration of 5-MAPB (1.6 × 10(-4) mol/kg B.W.) resulted in the death of two-thirds of the mice. The same dose of MDMA did not cause any deaths. The administration of 5-MAPB (1.6 × 10(-4) mol/kg B.W.) produced a 3.41°C ± 0.28°C rise in rectal temperature after 1 hr, whereas the administration of MDMA (1.6 × 10(-4) mol/kg B.W.) produced an approximate 1.85°C ± 0.26°C rise. These results suggest that benzofurans have 5-HT toxicity similar to MDMA, and 5-MAPB has a higher risk of lethal intoxication than MDMA. Furthermore, 5-APB, the metabolic product of 5-MAPB demethylation, may be involved in the acute 5-HT toxicity and may cause lethal intoxication in mice.

Reproductive and neurobehavioral effects of maternal exposure to piperonyl butoxide (PBO) in F1 -generation mice

Female mice were exposed maternally to piperonyl butoxide (PBO) through diet to provide levels of 0 (control), 0.015, 0.03, and 0.06% during gestation and lactation periods, and selected reproductive and neurobehavioral parameters were measured in F₁ generation. There was no adverse effect of PBO on litter size, litter weight, or sex ratio at birth. The average body weights of offspring showed no significant effects of PBO treatment through the lactation period in both sexes except for the low-dose group of females on PND 21. With respect to behavioral developmental parameters, swimming direction of female offspring on PND 7 was significantly accelerated in the low-dose group (p = 0.022). Exploratory behavior examination in male offspring indicated that total distance and movement time shortened significantly in dose-related manners (p = 0.0138 and 0.00231, respectively), average time of rearing lengthened significantly in a dose-related manner (p = 0.00814), and the frequencies of mice with urination was increased significantly in a dose-related manner (p < 0.05). For spontaneous behavior examination, the average time of movement in males and average time of rearing in females showed slightly dose-related effects in the F₁ generation. The dose levels of PBO in the present study produced some adverse effects in neurobehavioral parameters in mice.

Cytotoxic effects of psychotropic benzofuran derivatives, N-methyl-5-(2-aminopropyl)benzofuran and its N-demethylated derivative, on isolated rat hepatocytes

The novel psychoactive compounds derived from amphetamine have been illegally abused as recreational drugs, some of which are known to be hepatotoxic in humans and experimental animals. The cytotoxic effects and mechanisms of 5-(2-aminopropyl)benzofuran (5-APB) and N-methyl-5-(2-aminopropyl)benzofuran (5-MAPB), both of which are benzofuran analogues of amphetamine, and 3,4-methylenedioxy-N-methamphetamine (MDMA) were studied in freshly isolated rat hepatocytes. 5-MAPB caused not only concentration-dependent (0-4.0 mm) and time-dependent (0-3 h) cell death accompanied by the depletion of cellular ATP and reduced glutathione and protein thiol levels, but also accumulation of oxidized glutathione. Of the other analogues examined at a concentration of 4 mm, 5-MAPB/5-APB-induced cytotoxicity with the production of reactive oxygen species and loss of mitochondrial membrane potential was greater than that induced by MDMA. In isolated rat liver mitochondria, the benzofurans resulted in a greater increase in the rate of state 4 oxygen consumption than did MDMA, with a decrease in the rate of state 3 oxygen consumption. Furthermore, the benzofurans caused more of a rapid mitochondrial swelling dependent on the mitochondrial permeability transition than MDMA. 5-MAPB at a weakly toxic level (1 mm) was metabolized slowly: levels of 5-MAPB and 5-APB were approximately 0.9 mm and 50 μm, respectively, after 3 h incubation. Taken collectively, these results indicate that mitochondria are target organelles for the benzofuran analogues and MDMA, which elicit cytotoxicity through mitochondrial failure, and the onset of cytotoxicity may depend on the initial and/or residual concentrations of 5-MAPB rather than on those of its metabolite 5-APB. Copyright © 2016 John Wiley & Sons, Ltd.

Effects of Maternal Exposure to Piperonyl Butoxide (PBO) on Behavioral Development in F1-Generation Mice

Female mice were exposed maternally to piperonyl butoxide (PBO) through diet to provide dietary levels of 0% (control), 0.01%, 0.03%, and 0.09% during gestation and lactation periods, and selected reproductive and neurobehavioral parameters were measured in the F1 generation. There was no adverse effect of PBO on litter size, litter weight, or sex ratio at birth. The average body weights of male offspring decreased significantly in dose-related manners on postnatal days (PNDs) 0, 4, 7, and 14 (p = 0.0019, 0.0096, 0.033, and 0.038, respectively) during the lactation period. In female offspring, the average body weights decreased in dose-related manners on PNDs 0, 4, 7, and 14 (p = 0.0027, 0.0104, 0.0193, and 0.0062, respectively). The survival of dams slightly decreased (p = 0.0209) in the high-dose group during the lactation period. With respect to behavioral developmental parameters, surface righting on PND 7 of male and female offspring was delayed significantly in a dose-related manner (p < 0.001 in each). Swimming direction on PND 7 of male offspring was delayed significantly in a dose-related manner (p < 0.01), and for female offspring it was delayed significantly in the high-dose group (p < 0.05). Swimming head angle on PND 7 of male offspring was delayed significantly in a dose-related manner (p < 0.05). Spontaneous behavior examination in males indicated that rearing increased in the high-dose group in the F1 generation. The dose levels of PBO in the present study produced some adverse effects in neurobehavioral parameters in mice.

Comparative effects of sulfhydryl compounds on target organellae, nuclei and mitochondria, of hydroxylated fullerene-induced cytotoxicity in isolated rat hepatocytes

DNA damage and cytotoxicity induced by a hydroxylated fullerene [C60 (OH)24 ], which is a spherical nanomaterial and/or a water-soluble fullerene derivative, and their protection by sulfhydryl compounds were studied in freshly isolated rat hepatocytes. The exposure of hepatocytes to C60 (OH)24 at a concentration of 50 μM caused time (0 to 3 h)-dependent cell death accompanied by the formation of cell surface blebs, the loss of cellular levels of ATP and reduced glutathione, accumulation of glutathione disulfide, and induction of DNA fragmentation assayed using alkali single-cell agarose-gel electrophoresis. C60 (OH)24 -induced cytotoxicity was effectively prevented by pretreatment with sulfhydryl compounds. N-acetyl-L-cysteine (NAC), L-cysteine and L-methionine, at a concentration of 2.5 mM, ameliorated cell death, accompanied by a decrease in cellular ATP levels, formation of cell surface blebs, induction of reactive oxygen species (ROS) and loss of mitochondrial membrane potential caused by C60 (OH)24 . In addition, DNA fragmentation caused by C60 (OH)24 was also inhibited by NAC, whereas an antioxidant ascorbic acid did not affect C60 (OH)24 -induced cell death and DNA damage in rat hepatocytes. Taken collectively, these results indicate that incubation of rat hepatocytes with C60 (OH)24 elicits DNA damage, suggesting that nuclei as well as mitochondria are target sites of the hydroxylated fullerene; and induction of DNA damage and oxidative stress is ameliorated by an increase in cellular GSH levels, suggesting that the onset of toxic effects may be partially attributable to a thiol redox-state imbalance caused by C60 (OH)24 .

Effects of different types of bedding materials on behavioral development in laboratory CD1 mice (Mus musculus)

Male and female mice were housed in cages, containing different types of bedding materials (wood flakes or pulp chips), from 4 weeks of age in the F0 generation to 11 weeks of age in the F1 generation; selected reproductive and neurobehavioral parameters were measured in the F1 generation. There were no adverse effects of bedding materials on litter size, litter weight, or sex ratios at the time of birth. With regard to behavioral development parameters, bedding materials did not influence any variables (p > 0.05) in both sexes. Regarding exploratory behavior in the F1 generation, number of defecations significantly varied (p = 0.0203) with bedding materials in males at 3 weeks of age. The number of horizontal activities also significantly varied (p = 0.0342) with bedding materials in males at 8 weeks of age. Multiple-T water maze performance data indicated that the time required was significantly shortened across trials in pulp chips group than wood flakes group in males (p = 0.0211). Moreover, all spontaneous behavior variables in males significantly varied with bedding materials, particularly the average time of movement was significantly different (p = 0.0037) in distance between parallel lines of types of bedding materials in the F1 generation. The present study shows that bedding materials influence the neurobehavioral development in mice.

High-temperature calcined fullerene nanowhiskers as well as long needle-like multi-wall carbon nanotubes have abilities to induce NLRP3-mediated IL-1β secretion

Because multi-wall carbon nanotubes (MWCNTs) have asbestos-like shape and size, concerns about their pathogenicity have been raised. Contaminated metals of MWCNTs may also be responsible for their toxicity. In this study, we employed high-temperature calcined fullerene nanowhiskers (HTCFNWs), which are needle-like nanofibers composed of amorphous carbon having similar sizes to MWCNTs but neither metal impurities nor tubular structures, and investigated their ability to induce production a major proinflammatory cytokine IL-1β via the Nod-like receptor pyrin domain containing 3 (NLRP3)-containing flammasome-mediated mechanism. When exposed to THP-1 macrophages, long-HTCFNW exhibited robust IL-1β production as long and needle-like MWCNTs did, but short-HTCFNW caused very small effect. IL-1β release induced by long-HTCFNW as well as by long, needle-like MWCNTs was abolished by a caspase-1 inhibitor or siRNA-knockdown of NLRP3, indicating that NLRP3-inflammasome-mediated IL-1β production by these carbon nanofibers. Our findings indicate that the needle-like shape and length, but neither metal impurities nor tubular structures of MWCNTs were critical to robust NLRP3 activation.

Long-term Pulmonary Responses to Quadweekly Intermittent Intratracheal Spray Instillations of Magnetite (Fe3O4) Nanoparticles for 52 Weeks in Fischer 344 Rats

Information about potential risks of iron nanomaterials is still limited, while a wide variety of applications are expected. We recently reported acute phase responses of male and female Fischer 344 rats after a single intratracheal spray instillation of Fe₃O₄ nanoparticles (magnetite), clearly showing dose-dependent pulmonary inflammatory changes (Tada et al., J Toxicol Pathol 25, 233–239, 2012). The present study assessed long-term responses of male and female Fischer 344 rats to multiple administrations of magnetite. Ten-week-old male and female Fischer 344 rats (n=20/group) were exposed to a total of 13 quadweekly intermittent intratracheal spray instillations of magnetite during the experimental period of 52 weeks, at doses of 0, 0.2 (low), 1.0 (medium) and 5.0 (high-dose) mg/kg body weight per administration. Absolute and relative lung weights of the high-dose group were significantly higher than those of the control group. Macroscopically, slight enlargement and scattered black patches were recognized in the lungs and the lung-associated lymph nodes of the high-dose group. Histopathologically, infiltration of macrophages phagocytosing magnetite (all dose groups) and of chronic inflammatory cells (medium- and high-dose males and high-dose females), alveolar bronchiolization and granuloma (high-dose group) were observed. In addition, alveolar hyperplasias were observed in some rats of the high-dose group, and cytoplasmic overexpression of β-catenin protein was immunohistochemically found in such lesions. The present results clearly show that instilled magnetite causes chronic inflammatory responses in the lung. These responses occur in a dose-dependent manner without apparent differences among sexes

Effects of N-acetyl-L-cysteine on target sites of hydroxylated fullerene-induced cytotoxicity in isolated rat hepatocytes

The effects of N-acetyl-L-cysteine (NAC) on cytotoxicity caused by a hydroxylated fullerene [C60(OH)24], which is known a nanomaterial and/or a water-soluble fullerene derivative, were studied in freshly isolated rat hepatocytes. The exposure of hepatocytes to C60(OH)24 at a concentration of 0.1 mM caused time (0-3 h)-dependent cell death accompanied by the formation of cell blebs, loss of cellular ATP, and reduced glutathione (GSH) and protein thiol levels, as well as the accumulation of glutathione disulfide and malondialdehyde (MDA), indicating lipid peroxidation. Despite this, C60(OH)24-induced cytotoxicity was effectively prevented by NAC pretreatment ranging in concentrations from 1 to 5 mM. Further, the loss of mitochondrial membrane potential (MMP) and generation of oxygen radical species in hepatocytes incubated with C60(OH)24 were inhibited by pretreatment with NAC, which caused increases in cellular and/or mitochondrial levels of GSH, accompanied by increased levels of cysteine via enzymatic deacetylation of NAC. On the other hand, severe depletion of cellular GSH levels caused by diethyl maleate at a concentration of 1.25 mM led to the enhancement of C60(OH)24-induced cell death accompanied by a rapid loss of ATP. Taken collectively, these results indicate that pretreatment with NAC ameliorates (a) mitochondrial dysfunction linked to the depletion of ATP, MMP, and mitochondrial GSH level and (b) induction of oxidative stress assessed by reactive oxygen species generation, losses of intracellular GSH and protein thiol levels, and MDA formation caused by C60(OH)24, suggesting that the onset of toxic effects is at least partially attributable to a thiol redox-state imbalance as well as mitochondrial dysfunction related to oxidative phosphorylation.

Identification of heterotrophic plate count bacteria isolated from drinking water in Japan by DNA sequencing analysis

Heterotrophic plate count (HPC) test has been employed to indicate the effectiveness of water treatment processes and the microbiological condition of the distribution system. In Japan, because the majority of HPC bacteria are supposed to be harmless and all tap water should maintain residual chlorine, there are few studies of the virulence of HPC bacteria. In this study, we examined HPC bacteria isolated from finished and tap water for hemolytic activity to determine their virulence potential. 34 of 39 colonies expressing hemolytic activity were identified by partial 16S rDNA sequencing, but some of their percent identity were relatively low. This may have been due to the mismatching of the primer pair with some strains, or these strains may be unidentified new species. A total of 30 of 34 isolates identified have been reported to be opportunistic pathogens or food poisoning bacteria. To control the growth of these opportunistic pathogens among HPC bacteria, appropriate water quality control must always be done and residual chlorine must be maintained in every tap for a safe water supply.

Development and evaluation of a reverse transcription-loop-mediated isothermal amplification assay for rapid and high-sensitive detection of Cryptosporidium in water samples

We describe a novel assay for simple, rapid and high-sensitive detection of Cryptosporidium oocysts in water samples using a reverse transcription-loop-mediated isothermal amplification (RT-LAMP). The assay is based on the detection of 18S rRNA specific for Cryptosporidium oocysts. The detection limit of the developed RT-LAMP assay was as low as 6 x 10(-3) oocysts/test tube, which theoretically enables us to detect a Cryptosporidium oocyst and perform duplicated tests even if water samples contain only one oocyst. The developed RT-LAMP assay could more sensitively detect Cryptosporidium oocysts in real water samples than the conventional assay based on microscopic observation.

Comparative analyses of canine distemper viral isolates from clinical cases of canine distemper in vaccinated dogs

Sequence and phylogenetic analyses of three isolates of canine distemper virus (CDV) isolated from three dogs with a vaccination history were compared with the same analyses of vaccine virus isolated from a vaccine used for dogs. The three dogs showed clinical signs of a recent major type of CD in Japan, including oculonasal discharge and diarrhea, and pathological findings including non-suppurative encephalitis, pneumonia, mild gastroenteritis and lymphoid depletion. Inclusion bodies were in the stomach without inflammation and encephalitis was without clinical signs. One of the highest titers of CDV in different organs of the three dogs was commonly systemic lymphatic organs, including the spleen, lymph nodes and tonsils. New isolates of CDV joined to the clades of the Asia 1 group that is far from the vaccine group. These results surely indicate that wild strains of CDV from dogs with a vaccination history were not reversed vaccine virus, and that the dogs showed characteristics of recent CD in Japan.

Pathogenesis and phylogenetic analyses of canine distemper virus strain 007Lm, a new isolate in dogs

The pathogenesis of a new isolate of canine distemper virus (CDV), strain 007Lm, was investigated from lymph node tissue by using Vero cells that express canine signalling lymphocyte activation molecules with a tag (Vero-DST) in dogs. Two CDV sero-negative Beagle dogs were inoculated intranasally and intraconjunctively with a virus suspension. Both infected dogs showed clinical signs of severe bloody diarrhea, conjunctivitis, ocular discharge, nasal discharge and coughing, lymphopenia, fever and weight loss. Titers of CDV-IgM and CDV-IgG in the blood were measured. CDV was detected by using reverse transcriptase-PCR and was recovered in swabs from one dog from 9 days and from the other dogs from 10 days after inoculation. Molecular and phylogenetic analyses of H and P genes showed that nucleotide and amino acid sequences of these genes of strain 007Lm after isolation in Vero-DST cells are identical to those of the original virus from fresh tissue and that strain 007Lm joins to the Asia 2 group cluster of CDV strains that is distinct from other clusters. These results indicate that (1) CDV strain 007Lm isolated in Vero-DST cells is virulent, (2) nucleotide and amino acid sequences of H and P genes of strain 007Lm do not change after isolation in Vero-DST cells compared with the original virus from fresh tissue and (3) strain 007Lm isolated from a vaccinated dog belongs to a cluster far from the vaccine strains in the phylogenetic trees of H and P genes.

Experimental observation of disorder-driven hysteresis-loop criticality

We have studied the effect of magnetic disorder on the magnetization reversal process in thin Co/CoO films. The antiferromagnetic CoO layer allows a reversible tuning of the magnetic disorder by simple temperature variation. For temperatures above a critical temperature T(c), we observe a discontinuous magnetization reversal, whereas smooth magnetization loops occur for T<T(c). Our measurements establish the existence of a disorder-driven critical point in the nonequilibrium phase diagram. In addition, we observe scaling behavior in the vicinity of the critical point and determine the critical exponents beta = 0.022+/-0.006 and betadelta = 0.30+/-0.03 for this two-dimensional system.

Coronary arterial lesions induced by endothelin antagonists

Endothelins are potent vasoconstrictors and pressor peptides and are important mediators of cardiac, renal and endocrine functions. Increased ET-1 levels in disease states such as congestive heart failure, pulmonary hypertension, acute myocardial infarction, and renal failure suggest the endothelin system as an attractive target for pharmacotherapy. A non-peptidic, selective, competitive endothelin receptor antagonist with an affinity for the ET(A) receptor in the subnanomolar range was administered by continuous intravenous infusion to beagle dogs, rats, and Goettingen minipigs. It caused mild arteriopathy characterised by segmental degeneration in the media of mid- to large-size coronary arteries in the heart of dog, but not rat or minipig. The lesions only occurred in the atrium and ventricle. Frequency and severity of the vascular lesions was not sex or dose related. No effects were noted in blood vessels in other organs or tissue. Plasma concentrations at steady state, and overall exposure in terms of AUC((0-24h)) were higher in minipig and rat than the dog but did not cause cardiac arteriopathy. These findings concur with those caused by other endothelin anatagonists, vasodilators and positive inotropic/vasodilating drugs such as potassium channel openers, phosphodiesterase inhibitors and peripheral vasodilators, and confirm that dogs appear to be uniquely sensitive to the development of cardiac vascular lesions.