Aim: Non-cell corynebacterium parvum product (NCPP) is a new preparation of corynebacterium parvum (CP), an immunomodulator that displays anticancer activities. It is prepared by nanotechnology and is intended to minimize the side effects of CP. The aim of the present study was to evaluate the immunogenicity and systemic toxicity of NCPP compared with CP in animals. Methods: 30 monkeys were randomly divided into 5 groups and given CP (3 mg/monkey), three doses of NCPP (9, 3, 1 mg/monkey) and 0.9% normal saline (NS, 4 ml/monkey) individually by intramuscular injection twice a week for 13 weeks. The immunogenicity and systemic toxicity of NCPP and CP were compared. Results: NCCP and CP caused histopathological changes in the liver, spleen and kidney, but pathologic changes in NCCP-treated groups were slighter than that in the CP group. Only 9 mg/monkey of NCPP caused the similar damage as the CP in intensity. Deposition of immune complexes in the glomerular basement membrane was observed only in the CP group. ELISA detection showed that the anti-CP antibody was at a high level, while the anti-NCPP antibody was at low level and disappeared during the recovery period. Conclusion: Our study has led to the view that NCPP is safer than CP.
Vascular toxicity is important for understanding the neurotoxicity of methylmercury, because microvessels strongly influence the construction of microenvironment around neurons. Previously, we found that low density-human brain microvascular pericytes are markedly susceptible to methylmercury cytotoxicity due to high expression levels of the L-type amino acid transporter 1 (LAT-1) that transports methylmercury into the cells. Although LAT-1 can be, in general, highly expressed in sparse cells that require amino acids for growth, we found that human brain microvascular endothelial cells, regardless of cell density, were resistant to methylmercury cytotoxicity. To investigate the mechanisms underlying this resistance, we exposed the endothelial cells at low and high cell densities to methylmercury and determined the extent of nonspecific cell damage, intracellular accumulation of methylmercury, expression of LAT-1 and LAT-2 mRNAs, and intracellular expression of reduced glutathione and metallothionein. These experiments indicate that sparse endothelial cells intracellularly accumulate more methylmercury via the highly expressed LAT-1, but are resistant to methylmercury cytotoxicity by higher expression of the protective sulfhydryl peptides, namely, reduced glutathione and metallothionein. It is suggested that both nonspecific and functional damage is caused in pericytes, whereas functional abnormalities rather than nonspecific damage may occur to a greater extent in the endothelial cells in the brain microvessels exposed to methylmercury. The previous and present data also suggest that methylmercury exhibits toxicity in endothelial cells in a manner different from that in pericytes in the brain microvessels.
Because histopathological findings are often conclusive indicators of the toxicities of chemicals, standardization of nomenclature and construction of a thesaurus for histopathological findings are important for the comparative evaluation of histopathological data from repeated-dose toxicity studies (RTS). However, terms for histopathological findings have not been standardized and different technical terms are used to indicate almost the same thing in RTS. The present study was conducted to construct an easy-to-use thesaurus for histopathological findings in order to facilitate hazard assessments of untested chemicals by the category approach using knowledge of the toxicity of analogue chemicals. We used reports of 28-day RTS, conducted on rats by gavage, which were posted on the websites of the National Institute of Health Sciences (NIHS) and the National Institute of Technology and Evaluation (NITE). The histopathological data were from 156 reports on RTS conducted by 13 institutions in Japan. As a result of this study, major parts of the thesaurus were devoted to the findings in the liver, kidney, stomach, adrenal, thyroid and testis; the first three organs are known to be the main targets of chemicals. We also decided that findings such as swelling and enlargement of hepatocytes should be categorized as synonyms for terms meaning hypertrophy. Our thesaurus will be helpful in assessing or screening new untested chemicals by the category approach using knowledge of the toxicities of analogues of the new chemical. The RTS database with this thesaurus will be made publically available in 2012.
This study was conducted to evaluate the effects of procymidone (PCM) on development of male rabbit fetal external genitalia. PCM was administered once daily by gavage at dose levels of 0 (control) and 125 mg/kg/day to pregnant rabbits from gestation day 6 through 28 and fetal external genitalia was observed in detail. This treatment period covered the critical stage of sexual differentiation of fetal external genitalia in rabbits. In the maternal animals, food consumption was reduced in the PCM group. There were no effects of PCM on maternal caesarean sectioning data or fetal external observations. In fetal external genitalia observations, there were no significant differences between the control and PCM treatment group in any of the following parameters: ano-genital distance (AGD), phallus boundary-genital distance, diameter of preputial lamella, ventral gap of preputial lamella, or ventral gap to diameter ration of preputial lamella, though severe feminization such as decreasing of AGD and hypospadias in male rat offspring at the dose level of 125 mg/kg of PCM were reported. These results suggest that PCM has no effect on fetal external genitalia development in male rabbit fetuses, and species difference of developmental effects of PCM on sexual differentiation exists.
Higher blood levels of perfluorooctane sulfonate (PFOS) in males than the females have been observed in many human biomonitoring studies, which is not well explained yet. The effects of gestation and regular bleeding on blood PFOS level in mice were investigated to evaluate the potential factors that could result in the sex difference. The mice were exposed to PFOS via drinking water at a concentration of 50 μg/l. After 6 weeks of pre-exposure and the gestation period, the blood PFOS concentrations in the gestagenic mice were significantly lower than the control non-gestagenic mice with a ratio of 0.45. Significant lower blood PFOS concentrations in the male mice treated by regular artificial bleeding were observed compared with those from the control male. However, such difference was not observed for the females. The sex difference in the effect of regular artificial bleeding on the blood PFOS level may be caused by the different accumulation and elimination rate in the female and male mice. In addition, the effect of intermittent exposure to PFOS on blood level was evaluated. Each single exposure caused a significant increase in blood PFOS level in both females and males, suggesting the acute exposure to PFOS occurred before the blood sampling, e.g. exposure to PFOS-contaminated foods or drinks, would affect the biomonitoring data to some extent depending on the background blood level. Thus serial blood monitoring is required to obtain accurate body burden.
This study was designed to evaluate any adverse effect of fermentation-derived cellulose, produced by Acetobacter aceti subspecies xylinum, when administered to both sexes of F344 rats at dietary levels of 0, 1.25, 2.5, and 5.0% for 28 days. The treatment had no adverse effects on clinical signs, mortality, body weights and food and water consumption, or on urinalysis, ophthalmology, hematology, blood biochemistry, and histopathology findings. At necropsy, slight increased absolute and relative cecum weights, evident in females ingesting 2.5% and 5.0% dietary levels, were considered to be a physiological adaptation to the poorly absorbed fermentation-derived cellulose. The non-observed-adverse-effect level (NOAEL) from the present study was concluded to be 5.0% in the diet (5,331 mg/kg body weights/day for males, and 5,230 mg/kg body weights/day for females).
Acute and chronic inflammatory diseases are associated with the induction of inducible nitric oxide synthase (iNOS) and inducible heme oxygenase (HO-1). These inducible enzymes are up-regulated in macrophages subjected to inflammatory stimuli and oxidative stress. β2-Adrenoceptor (AR) agonists, which function as bronchial dilators, are widely used for the treatment of asthma and chronic obstructive pulmonary disease (COPD). We examined whether salbutamol, a classical β2-AR agonist, inhibits the induction of proinflammatory cytokines and stress inducible proteins. Rat macrophages obtained from the abdominal cavity were incubated with lipopolysaccharide (LPS) with or without salbutamol. Induction by LPS of tumor necrosis factor (TNF)-α and interleukin (IL)-6 was significantly inhibited (P < 0.05) by salbutamol treatment. Induction by LPS of iNOS mRNA and protein was also significantly inhibited (P < 0.05) by salbutamol. LPS-mediated increases in HO-1 mRNA and protein were not appreciably affected by salbutamol. One of the anti-inflammatory mechanisms of salbutamol was thus found to be inhibition of induction by LPS of extracellular stimulus-responsive kinase (ERK) 1/2 in macrophages. These findings suggest that salbutamol has the potential for use as an anti-inflammatory agent due to its suppression of LPS-induced TNF-α, and IL-6 and iNOS via ERK pathway without affecting HO-1 expression.
This paper shows the detection of Diarrhetic Shellfish Poison (DSP) phycotoxins, using HPLC-FLD with pre-column derivatization procedure and HPLC-MS methods, in the analysis of shellfish extracts tested positive with the official DSP mouse bioassay. The shellfish samples were collected in Chiloe Island, Southern of Chile. The amount of Dinophysistoxin-3 (DTX-3) measured in the shellfish extracts were in average above the international safe limits for DSP content in the shellfish extracts analyzed. As internal control of detection and recovery, DTX-1 analytical standard was spiked into dichloromethane–clean shellfish extracts in order to calculate de extraction recovery of DTX-1. The average recovery was 97%. From all DSP toxins analyzed, the hydrolyzed extract samples appeared mainly DTX-3 in concentrations ranging from 99.40 ± 1.22 to 257.73 ± 12.46 ng/g digestive-glands. The acyl-Okadaic Acid (acyl-OA) was also detected in some samples, ranging from 1.02 ± 1.4 to 3.07. ± 1.6 ng of DSP toxin/g digestive-glands. This is the first report of acyl-OA ever found in Chilean shellfish samples. This data shows that shellfish samples were contaminated with a complex DSP toxins profile, in which DTX-3 is the major DSP toxin component, followed by DTX-1 and the acyl-OA as the minor one. The important findings showed in this study are the presence of both acyl-derivates (DTX-3 and Acyl-OA) which are the product of a main metabolic biotransformation that occurred inside the shellfish, in order to chelate DTX-1 and OA, transforming them into DTX-3 and the acyl-OA respectively. This metabolic biotransformation must be performed to avoid self-inhibition of their Protein Phosphatase 2A done by DTX-1 and OA, since both acyl-derivates (DTX-3 and acyl-OA) do not inhibit Protein Phosphatase 2A. This complex DSP toxins profile and the permanent presence of both acyl-derivates (DTX-3 and Acyl-OA) could explain the permanent diarrhea symptoms that experience patients who have ingested cooked shellfish in the southern of Chile. This diarrhea is not associated to Vibrio parahaemolyticus or other enteropathogens as had been suggested before. The massive shellfish consumption is an important Chilean cultural habit and now has become a major health issue in the southern of Chile.
Sulfur mustard (HD), a very potent alkylating agent and lipopolysacchride (LPS), are both well characterized inflammatory factors. We have found that concomitant exposure of murine macrophage cells (RAW264.7) to LPS and HD induced protection against HD induced cytotoxicity. Both HD and LPS induce release of inflammatory markers in RAW264.7 cells. However, there are marked differences in the repertoire of inflammatory factors released by the two toxins: While exposure to HD, induced a dose-dependant death of these cells, no significant change in survival rate was observed following LPS (1-100 ng/ml) exposure. Additionally, LPS elicited a robust nitric oxide (NO) and TNF-α secretion whereas HD was practically ineffective. Both toxins increased PGE2 secretion in a concentration dependent manner. Treatment of HD-exposed RAW264.7 cells with anti-inflammatory drugs such as dexamethazone (5 μM), voltaren (diclofenac) (8 μM) or doxycycline (5 μM), decreased the release of cytokines but had no effect on cell viability. Simultaneous application of LPS (100 ng/ml) and HD (20-100 μM) resulted in an amelioration of HD cytotoxicity. Adding the NO generator S-nitrosoglutathione (GSNO) or inhibiting NO production using L-NG-monomethyl Arginine, had no effect on cell viability. Moreover, addition of PGE2 (20 ng/ml) failed to induce any changes in cell viability under basal or HD-induced toxicity. In contrast, TNF-α (20 ng/ml) provided remarkable protection against HD-induced cell death. These findings strongly suggest that LPS exerts its protective action against HD toxicity through the generation of TNF-α and may provide better understanding of the mechanism of cytoprotection.
This study was conducted to measure the antibacterial activity of grape (Vitis vinifera L; Vitaceae) seed extract against methicillin-resistant Staphylococcus aureus (MRSA). Grape seed and skin extracts were tested for antibacterial activity against forty-three strains of MRSA by gel diffusion, growth and respirometric studies. All MRSA strains were found to be sensitive to grape seed extract. Complete inhibition of all bacterial strains tested was observed at a concentration of 3 mg/ml crude grape seed proanthocyanidins extract (GPSE), equivalent of 20.7 µg/ml flavonoid content. Antibacterial activity was bactericidal as shown by a disruption of the bacterial cell wall in scanning and transmission electron microscopy. Grape seed extract is known to be rich in potent antioxidant polyphenolics that could show antibacterial activity. Phenolic compounds in the grape seed extract were assayed by Folin-Ciocalteu’s reagent. The considerable antibacterial activity of commonly available grape seed extract could signify a major advancement in the treatment of MRSA diseases.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) reduces the synthesis of pituitary gonadotropins in a fetal age-specific manner. The pituitary synthesis of gonadotropins is regulated by the hypothalamus and, thus, needs the differentiation and development of the hypothalamus requiring a number of factors including energy supply and neurotransmitters. To investigate the mechanism whereby TCDD reduces fetal gonadotropins, we carried out a comparative study on the metabolomes of the hypothalamus and pituitary using fetal and mature Wistar rats. Male fetuses at gestational day (GD)20 were removed from dams treated orally with TCDD (1 µg/kg) at GD15, and the metabolome profiles were analyzed by gas chromatography-mass spectrometry (GC-MS). The principal component analysis of GC-MS data revealed that TCDD caused a change in the profile of fetal metabolome more markedly in the hypothalamus than in the pituitary. In sharp contrast, TCDD did not cause any marked alteration in hypothalamic as well as pituitary metabolomes in male rats born of untreated dams and treated with TCDD at postnatal day 49. It was also demonstrated that a number of fetal hypothalamic components, including glutamine and γ-aminobutyric acid, are reduced by TCDD. These results demonstrate a possibility that TCDD may reduce the metabolic activity of the hypothalamus in a fetus-specific fashion, resulting in the reduced synthesis of gonadotropins.
3,4-Methylenedioxymethamphetamine (MDMA) is widely abused as a psychoactive recreational drug. It is well known that MDMA induces neurotoxic damage of serotonergic nerve endings. Although drug abuse is increasing among youths, it is unclear whether recreational drugs affect the development of nerve growth. Thus, the present study examined the effect of recreational drugs, such as MDMA, 3,4-methylenedioxyamphetamine (MDA) and diphenylprolinol, a novel recreational drug with a similar chemical structure as that of psychoactive agent pipradrol, on nerve growth factor (NGF)-induced neurite outgrowth. These recreational drugs induced a dose-dependent cell death in PC12 cells. The IC50 values of MDMA, MDA, R-diphenylprolinol and S-diphenylprolinol were 4.11 mM, 2.75 mM, 1.00 mM and 0.77 mM, respectively, at 24 hr. To examine the effects of these recreational drugs on NGF-induced neurite outgrowth, PC12 cells were treated with NGF together with MDMA, MDA, S-diphenylprolinol or R-diphenylprolinol at low toxic concentrations. The recreational drugs significantly suppressed neurite outgrowth of PC12 cells induced by NGF. The results suggest that these psychoactive recreational drugs may inhibit neurite growth and thus be implicated in their elicited neurotoxicity.
We examined the effects of exogenous melatonin and the time of its administration on core body temperature (CBT) and heart rate (HR) in cynomolgus monkeys. Doses of melatonin at 0.2, 2, 20 and 200 mg/kg were administered by oral gavage once daily at different times. With administration at 09.00 h, melatonin dose-dependently suppressed CBT and the effect reached statistical significance at 200 mg/kg. With administration at 16.00 h, the suppressive effect on CBT was not evident for several hours after administration possibly due to masking by the normal robust CBT decline. Unexpectedly, melatonin inhibited the normal CBT decline thereafter and this resulted in an upward shift of the CBT nadir during the dark phase especially with 200 mg/kg. The HR showed a similar upward shift at that time. Any effects on the CBT and HR from melatonin administration were not inhibited by luzindole, an MT1/MT2 receptor antagonist, whereas N-acetyl-5-hydroxytryptamine, a ligand of the MT3 binding site, mimicked all the actions of melatonin. To our knowledge, this is the first time it has been shown that melatonin administered in the early evening promotes upward shifting of the CBT and HR in the nighttime in addition to the daytime decrease in the CBT. These changes may be mediated, at least partly, through the MT3 binding site.
The side effects that occur in the central nervous system and circulatory system due to medicines are expected to be prevented by research and development. However, many of the compounds in medicines have the possibility of causing arrhythmia, and methods developed to detect this problem at the early stage of drug development are not always successful. In the present study, we classified drug compounds according to their activity using only structural information. To classify compounds, we used a self-organizing map (SOM), which is a nonlinear unsupervised classification method. We first analyzed a small-scale dataset, and an excellent classification result was obtained. We then applied our method to a large-scale dataset containing numerous inert compounds and were again able to classify the compounds according to their activity. Both classifications showed some compound activity, although a few differences between the two SOM maps were seen.
We evaluated the safety of water-soluble polymer-enwrapped fullerenes (PVP/fullerenes) as antioxidants in cosmetic and pharmaceutical preparations by studying the genotoxicity, phototoxicity, and pro-oxidant effects of these fullerenes. These materials were not mutagenic to any of the tested bacterial strains and did not induce chromosomal aberrations in cultured mammalian cells. The PVP/fullerenes did not exhibit cytotoxicity under ultraviolet or sham irradiation in the alternative phototoxicity test. Moreover, they did not show any pro-oxidant effect in the presence of Fe2+ or Cu2+. Thus, we concluded that PVP/fullerenes are safe for use in cosmetic and pharmaceutical applications. This is the first study in which toxicity tests were performed on PVP/fullerenes.
A new OECD test guideline 431 (TG431) for in vitro skin corrosion tests using human reconstructed skin models was adopted by OECD in 2004. TG431 defines the criteria for the general function and performance of applicable skin models. In order to confirm that the new reconstructed human epidermal model, LabCyte EPI-MODEL is applicable for the skin corrosion test according to TG431, the predictability and repeatability of the model for the skin corrosion test was evaluated. The test was performed according to the test protocol described in TG431. Based on the knowledge that LabCyte EPI-MODEL is an epidermal model as well as EpiDerm, we decided to adopt the the Epiderm prediction model of skin corrosion for the LabCyte EPI-MODEL, using twenty test chemicals (10 corrosive chemicals and 10 non-corrosive chemicals) in the 1st stage. The prediction model results showed that the distinction of non-corrosion to corrosion corresponded perfectly. Therefore, it was judged that the prediction model of EpiDerm could be applied to the LabCyte EPI-MODEL. In the 2nd stage, the repeatability of this test protocol with the LabCyte EPI-MODEL was examined using twelve chemicals (6 corrosive chemicals and 6 non-corrosive chemicals) that are described in TG431, and these results recognized a high repeatability and accurate predictability. It was concluded that LabCyte EPI-MODEL is applicable for the skin corrosive test protocol according to TG431.
Our previous study indicated that Nrf2 is a key transcription factor in cellular defenses against inorganic arsenite (iAsIII). However, the role of heme oxygenase-1 (HO-1), which is regulated by Nrf2, in iAsIII-induced cytotoxicity is poorly understood. To address this issue, we examined the contribution of HO-1 to iAsIII-mediated Nrf2 activation and in protection against iAsIII cytotoxicity in HepG2 cells. Exposure of HepG2 cells to iAsIII (10 µM) caused persistent induction of HO-1 accompanied by prolonged Nrf2 activation, whereas siRNA-mediated knockdown of HO-1 decreased prolonged Nrf2 activation. Pretreatment with either HO-1 siRNA or HO inhibitor (tin protoporphyrin IX) significantly enhanced iAsIII-induced cytotoxicity. These results suggest that iAsIII-induced HO-1 appears, at least in part, to act as a positive feedback regulator of Nrf2 activation, thereby diminishing its cytotoxicity in HepG2 cells.