Assessment of respiratory and systemic toxicity of Benzalkonium chloride following a 14-day inhalation study in rats.

BACKGROUND: Although biocides at low concentrations have been used to control pests, they can be more harmful than industrial chemicals as humans are directly and frequently exposed to such biocides. Benzalkonium chloride (BAC or BKC) is a non-toxic substance used to control pests. Recently, BAC has been increasingly used as a component in humidifier disinfectants in Korea, raising a serious health concern. Moreover, it poses significant health hazards to workers handling the chemical because of direct exposure. In the present study, we aimed to evaluate the respiratory toxicity of BAC due to its inhalation at exposure concentrations of 0.8 (T1 group), 4 (T2 group) and 20 (T3 group) mg/m3. RESULTS: In our previous study on the acute inhalational toxicity of BAC, bleeding from the nasal cavity was observed in all the rats after exposure to 50 mg/m3 BAC. Therefore, in this study, 20 mg/m3 was set as the highest exposure concentration, followed by 4 and 0.8 mg/m3 as the medium and low concentrations for 6 h/day and 14 days, respectively. After exposure, recovery periods of 2 and 4 weeks were provided. Additionally, alveolar lavage fluid was analyzed in males of the BAC-exposed groups at the end of exposure and 2 weeks after exposure to evaluate oxidative damage. In the T3 group exposed to BAC, deep breathing, hoarseness, and nasal discharge were observed along with a decline in feed intake and body weight, and nasal discharge was also observed in the T1 and T2 groups. ROS/RNS, IL-1ß, IL-6, and MIP-2 levels decreased in a concentration-dependent manner in the bronchoalveolar lavage fluid. Histopathological examination showed cellular changes in the nasal cavity and the lungs of the TI, T2, and T3 groups. CONCLUSIONS: As a result, it was confirmed that the target organs in the respiratory system were the nasal cavity and the lungs. The adverse effects were evaluated as reversible responses to oxidative damage. Furthermore, the no observed adverse effect level was found to be less than 0.8 mg/m3 and the lowest benchmark dose was 0.0031 mg/m3. Accordingly, the derived no-effect level of BAC was calculated as 0.000062 mg/m3.

Comparative genomic analysis of the human and nematode Caenorhabditis elegans uncovers potential reproductive genes and disease associations in humans.

Reproduction is an important biological process. However, studies of human reproduction at the molecular level are limited due to the difficulty of performing in vivo studies. Hence, a mechanistic understanding of human reproduction remains still poor. Thus, it is important to use an alternative model organism for mechanistic studies of human reproduction. In this study, we used the nematode Caenorhabditis elegans as a model for studying human reproduction and identified 61 human and 535 worm reproductive genes through a combination of comparative genomic and Gene Ontology (GO) analyses. Interestingly, in terms of sex specificity, the number of male-specific genes was greater than the number of female-specific genes. Gene enrichment analysis identified biologically significant processes such as protein localization to cajal bodies/telomeres/nuclear bodies/chromosomes, helicase activity, pyrimidine biosynthesis, and determination of adult lifespan. Regarding the analysis of human reproductive diseases among the identified genes, 10 and 12 genes were identified in the human- and C. elegans-based analyses, respectively. In addition, RNA interference knockdown of a newly identified F52H2.6/DHCR24 gene increased brood size and ovulation/egg-laying rate in C. elegans. Therefore, gene identification, disease associations, and a proof-of-concept experiment using C. elegans will not only provide insights into mechanistic study of human reproduction, but also demonstrate the utility in studying human reproduction.

Acid sphingomyelinase is required for cell surface presentation of Met receptor tyrosine kinase in cancer cells.

Receptor tyrosine kinases (RTKs) are embedded in the lipid bilayer of the plasma membrane, but the specific roles of various lipids in cell signaling remain largely uncharacterized. We have previously found that acid sphingomyelinase (ASM; also known as SMPD1) regulates the conserved DAF-2 (the ortholog IGF-1R in mammals) RTK signaling pathway in Caenorhabditis elegans How ASM and its catalytic products, ceramides, control RTK signaling pathways remain unclear. Here, we report that ASM regulates the homeostasis of Met, an RTK that is frequently overexpressed in various cancers. Inactivation of ASM led to a rapid loss of Met from the plasma membrane, reduced Met phosphorylation and activation, and induced Met accumulation in the trans-Golgi network (TGN). However, trafficking of integrin ß3 and vesicular stomatitis virus glycoprotein (VSVG) was largely unaffected. Knockdown of syntaxin 6 (STX6) also blocked the Golgi exit of Met. Depletion of either ASM or STX6 led to aberrant trafficking of Met to lysosomes, promoting its degradation. Our studies reveal that ASM and ceramides, together with STX6 and cholesterol, constitute a new regulatory mechanism for the exit of Met from the Golgi during its biosynthetic route, which is used to rapidly replenish and regulate the plasma membrane levels of Met in various cancer cells.

Subchronic oral toxicity study of Korean red ginseng extract in Sprague-Dawley rats with a 4-week recovery period.

Ginseng is a major herbal remedy used in Asian countries for thousands of years and known to restore and enhance vital energy. Korean red ginseng, which is processed by steaming and drying fresh Panax ginseng, is most popular and contains unique ginsenosides, which have anticancer and anti-inflammatory properties. The present study was carried out to evaluate the repeated oral dose toxicity of Korean red ginseng extract. The test article was administered orally once a day to male and female Sprague-Dawley rats at dose levels of 0, 500, 1000, or 2000 mg/kg/day for 13 consecutive weeks (15 animals/sex/group in the vehicle control and 2000 mg/kg/day groups, and 10 animals/sex/group in the 500 and 1000 mg/kg/day groups). Ten animals per group were sacrificed at the end of the 13-week treatment period, and the remaining rats were sacrificed after a 4-week recovery period. Administration of Korean red ginseng extract did not result in any toxicologically significant changes in mortality, body weight, food consumption, ophthalmoscopy, hematology, serum biochemistry, gross pathological findings, absolute/relative organ weights, or histopathology. It was established that the no observed adverse effect level (NOAEL) of the test article was 2000 mg/kg/day for both sexes in this study.

Qualitative and quantitative analysis of flavonoids from 12 species of Korean mulberry leaves.

The total flavonoids in leaves of 12 varieties of Korean mulberry (Morus alba L.) were determined. Seventeen flavonoids were isolated and analyzed using ultra-performance liquid chromatography coupled with diode array detection and quadrupole time-of-flight mass spectrometry (UPLC-DAD-QTOF/MS). To determine the flavonoid contents, HPLC analysis was performed on these 17 flavonoids. The total flavonoid contents of the 12 varieties of mulberry leaves ranged from 748.5 to 1297.9 mg, with the highest obtained from the Cheong Su variety (1297.9 ± 112.0 mg). Among the 17 flavonoids analyzed, quercetin 3-O-rutinoside (rutin) and quercetin 3-O-glucoside (isoquercitrin) had highest contents in the Cheong Su variety. Furthermore, the Dae Dang Sang variety gave the highest quercetin 3-O-rutinoside (rutin) content among the mulberry leaves investigated, at 425.5 ± 45.9 mg. Major flavonols from Dae Dang Sang were detected by UPLC-DAD-QTOF/MS. A total of 17 flavonoid compound peaks were identified in the analysis time range of 5-40 min, all of which were kaempferol and quercetin glycosides. Seven of the 17 compounds identified in mulberry leaves were unknown.

Twenty-eight-day repeated inhalation toxicity study of nano-sized lanthanum oxide in male sprague-dawley rats.

Although the use of lanthanum has increased in field of high-tech industry worldwide, potential adverse effects to human health and to the environment are largely unknown. The present study aimed to investigate the potential toxicity of nano-sized lanthanum oxide (La2 O3 ) following repeated inhalation exposure in male Sprague-Dawley rats. Male rats were exposed nose-only to nano-sized La2 O3 for 28 days (5 days/week) at doses of 0, 0.5, 2.5, and 10 mg/m3 . In the experimental period, we evaluated treatment-related changes including clinical signs, body weight, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology findings. We also analyzed lanthanum distribution in the major organs and in the blood, bronchoalveolar lavage fluids (BALF), and oxidative stress in lung tissues. Lanthanum level was highest in lung tissues and showed a dose-dependent relation. Alveolar proteinosis was observed in all treatment groups and was accompanied by an increase in lung weight; moreover, lung inflammation was observed in the 2.5 mg/m3 and higher dose groups and was accompanied by an increase in white blood cells. In the BALF, total cell counts including macrophages and neutrophils, lactate dehydrogenase, albumin, nitric oxide, and tumor necrosis factor-alpha increased significantly in all treatment groups. Furthermore, these changes tended to deteriorate in the 10 mg/m3 group at the end of the recovery period. In the present experimental conditions, we found that the lowest-observed-adverse-effect level of nano-sized La2 O3 was 0.5 mg/m3 in male rats, and the target organ was the lung. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1226-1240, 2017.

TATN-1 mutations reveal a novel role for tyrosine as a metabolic signal that influences developmental decisions and longevity in Caenorhabditis elegans.

Recent work has identified changes in the metabolism of the aromatic amino acid tyrosine as a risk factor for diabetes and a contributor to the development of liver cancer. While these findings could suggest a role for tyrosine as a direct regulator of the behavior of cells and tissues, evidence for this model is currently lacking. Through the use of RNAi and genetic mutants, we identify tatn-1, which is the worm ortholog of tyrosine aminotransferase and catalyzes the first step of the conserved tyrosine degradation pathway, as a novel regulator of the dauer decision and modulator of the daf-2 insulin/IGF-1-like (IGFR) signaling pathway in Caenorhabditis elegans. Mutations affecting tatn-1 elevate tyrosine levels in the animal, and enhance the effects of mutations in genes that lie within the daf-2/insulin signaling pathway or are otherwise upstream of daf-16/FOXO on both dauer formation and worm longevity. These effects are mediated by elevated tyrosine levels as supplemental dietary tyrosine mimics the phenotypes produced by a tatn-1 mutation, and the effects still occur when the enzymes needed to convert tyrosine into catecholamine neurotransmitters are missing. The effects on dauer formation and lifespan require the aak-2/AMPK gene, and tatn-1 mutations increase phospho-AAK-2 levels. In contrast, the daf-16/FOXO transcription factor is only partially required for the effects on dauer formation and not required for increased longevity. We also find that the controlled metabolism of tyrosine by tatn-1 may function normally in dauer formation because the expression of the TATN-1 protein is regulated both by daf-2/IGFR signaling and also by the same dietary and environmental cues which influence dauer formation. Our findings point to a novel role for tyrosine as a developmental regulator and modulator of longevity, and support a model where elevated tyrosine levels play a causal role in the development of diabetes and cancer in people.

The significant impact of MPs in the industrial/municipal effluents on the MPs abundance in the Nakdong River, South Korea.

Owing to extensive plastic consumption, wastewater from households, business establishments, and industrial activities have been recognised as a significant contributor to microplastics (MPs) in aquatic environments. This case study represents the first investigation of MPs in the Nakdong River, Republic of Korea, that traverses through the largest industrial complex midstream and densely populated cities of Daegu and Busan downstream before flowing into the sea. Monitoring of MP abundance in effluents discharged from three municipal, two industrial, and one livestock wastewater treatment plant (WWTP) into the Nakdong River was conducted over four seasons from August 2022 to April 2023. Identification and quantification of MPs were performed using micro-Fourier transform infrared spectrometry. Seasonal variation in MPs in the Nakdong River was found to be strongly influenced by the nearest upstream WWTPs and rivers, exhibiting a linear relationship that decreased gradually with increasing distance from the WWTPs. The average concentrations of MPs in the six effluent sources ranged from 101 ± 13 to 490 ± 240 particles/L during the yearly monitoring period, while MP concentrations in the river ranged between 79 ± 25 and 120 ± 43 particles/L. Industrial effluents contained higher amounts of discharged MPs (314 ± 78 particles/L) than municipal sources (201 ± 61 particles/L). Notably, two municipal WWTPs, located in the highly densely populated city, discharged the highest total MP amounts per day and released the greatest volumes of effluents. This study provides valuable insights into the monitoring and impact of effluents on MPs in rivers, which could inform MP treatment and management strategies for in river and marine environments.

Moral sensitivity relating to the application of the code of ethics.

This study investigated the clinical application of the 2006 Third Revised Korean Nurses' Code of Ethics and the moral sensitivity of nurses. A total of 303 clinical nurses in South Korea participated in the survey in May and June 2011. As instruments of this study, we used the 15 statements of the Korean Nurses' Code of Ethics and Korean Moral Sensitivity Questionnaire. The mean score for application was 3.77 ± 0.59 (out of 5), and the mean score for moral sensitivity was 5.14 ± 0.55 (out of 7). The correlation coefficient (r) of the application and moral sensitivity was 0.336 (p < 0.001). Nurses who scored high on moral sensitivity also scored high on application (t = -5.018, p < 0.001). In clinical settings, educational programmes to develop the moral sensitivity of nurses are necessary for improving the application of the code of ethics.

The effects of 4-week inhalation exposure to titanium nitride on lungs of Sprague-Dawley rats.

Titanium nitride (TiN) is a ceramic material with physical properties such as extreme hardness, high decomposition temperature, defect structure, and gold-yellow color. TiN is generally considered non-toxic and safe; however, hazards have not been identified, especially in workers after inhalation exposure. Here, we conducted a four-week inhalation toxicity study of TiN using a nose-only inhalation exposure system in Sprague-Dawley rats. Rats were exposed to TiN for 4 weeks (6 h a day, 5 days per week) at target concentrations of 45, 90, and 180 mg/m3. Clinical signs, mean body weight changes, hematology, blood biochemistry, necropsy, organ weight, bronchoalveolar lavage fluid analysis, and histopathological findings were observed. Analytical concentrations of the low, middle, and high-concentration groups were 45.55 ± 3.18 mg/m3, 90.69 ± 7.30 mg/m3, and 183.87 ± 15.21 mg/m3, respectively. The mass median aerodynamic diameter (MMAD) for the low, middle, and high-concentration groups were 1.44 ± 0.07 µm, 1.47 ± 0.18 µm, and 1.68 ± 0.16 µm, and the geometric standard deviation (GSD) was 2.24 ± 0.03, 2.31 ± 0.16, and 2.43 ± 0.11, respectively. No systemic adverse effects were observed after inhalation exposure to TiN; however, histopathological findings (increased phagocytic macrophages and alveolar/bronchiolar epithelial hyperplasia) and Bronchoalveolar Lavage Fluid (BALF) analysis (elevated lactate dehydrogenase and gamma-glutamyltransferase values) showed adverse effects on the lungs in the middle and high-concentration groups. Based on these results, the no observed adverse effect concentration (NOAEC) is suggested to be 45 mg/m3.

N-methylformamide induces multiple organ toxicity in Fischer 344 rats.

N-Methylformamide (NMF) is a widely used chemical (CAS No.: 123-39-7) in several industries and its usage is continuously increasing. However, studies for NMF have been focused on hepatotoxicity from now. Its toxicity profile has not yet been established owing to limited toxicity data. Therefore, we evaluated systemic toxicity via NMF inhalation. We exposed 0, 30, 100, and 300 ppm NMF to Fischer 344 rats for 6 h/day, 5 days a week for 2 weeks. Clinical signs, body weights, food consumption, hematologic parameters, serum chemistry measurements, organ weights, necropsy, and histopathology were performed. Two females exposed to 300 ppm NMF died during exposure period. Decrease of food consumption and body weight in both sexes exposed to 300 ppm in females exposed to 100 ppm were noted during exposure period. Increased RBC and HGB were noted in females exposed to 300 ppm. A decrease in the levels of ALP and K and increase in the levels of TCHO and Na were observed in both sexes exposed to 300 and 100 ppm. Increased levels of ALT, AST, BUN and decreased levels of TP, ALB, Ca were observed in females exposed to 300 and 100 ppm. The relative liver weight was elevated in both sexes exposed to 300 and 100 ppm NMF. Hypertrophy in the liver and submandibular glands and nasal cavity injuries were noted in both sexes exposed to 300 and 100 ppm NMF. Tubular basophilia of the kidneys were noted in females exposed to 300 ppm NMF. We revealed that NMF affect several organs including the kidneys not only the liver and NMF-related toxicity is predominant in female rats. These results could contribute to the development of NMF toxicity profile and may help in developing strategies for the control of occupational environmental hazards related to NMF.

Evaluation of subchronic oral dose toxicity and allergen of freeze-dried powder of Locusta migratoria (Orthoptera: Acrididae) as a novel food source.

The migratory locust, Locusta migratoria (Orthoptera: Acrididae), is a well-known edible insect which may serve as new source of human food and animal feed. However, potential toxicity and food safety of L. migratoria had not been investigated extensively until now. Therefore, in this study, we aimed to investigate toxicity of freeze-dried powder of L. migratoria (fdLM) and identify allergic components in ELISA and PCR techniques. In this subchronic study, fdLM was administered once daily by oral gavage at the doses of 750, 1500, and 3000 mg/kg/day. No toxicological changes were observed in both sexes of rats for 13 weeks in accordance with the OECD guidelines and GLP conditions. In addition, fdLM did not induced increases of serum immunoglobulin E and 21 homologous proteins were not detected under our present conditions. In conclusion, the NOAEL (no-observed-adverse-effect level) was 3000 mg/kg/day and no target organ was identified in both sexes. In conclusion, we found that fdLM is safe with no adverse effects and offers the potential of its use as an edible ingredient or other biological uses.

Hepatoprotective effects on alcoholic liver disease of fermented silkworms with Bacillus subtilis and Aspergillus kawachii.

The purpose of this study was to investigate the protective effect of Bacillus subtilis fermented silkworm powder (BFSP) and Aspergillus kawachii fermented silkworms powder (AFSP) on alcohol-induced hepatotoxicity in Sprague-Dawley rats. Alcohol-feeding rats were fed with diets containing silkworm powder (SP) or both BFSP and AFSP at the 5% (w/w) levels for 4 weeks. Alcohol administration resulted in a significant increase in the activities of liver marker enzymes, aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GTP) and lactate dehydrogenase (LDH). Administration of BFSP markedly prevented alcohol-induced elevation of serum AST, γ-GTP and LDH activities, and the levels of blood alcohol and acetaldehyde. Interestingly, in comparison with both SP and AFSP, BFSP administration drastically increased both hepatic alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activities, suggesting that BFSP was more effective in the reduction of blood alcohol and acetaldehyde. BFSP administration showed the highest induction of hepatic ADH expression in alcohol-feeding rats. Also, alcohol treatment resulted in increasing lipid peroxidative index (thiobarbituric acid-reactive substances) and decreasing antioxidant status (reduced glutathione) in the liver. Thus, these results suggest that BFSP treatment improved the antioxidant status of alcoholic rats by decreasing the levels of lipid peroxidative index and by increasing the levels of antioxidant status in the liver and serum. Specially, the concentrations of serum total cholesterol, free fatty acid and hepatic triglyceride were increased, but these parameters were significantly influenced by the BFSP in the alcohol treatment. Unlike the action of alcohol treatment on fatty liver, BFSP administration attenuated lipid droplet accumulation in hepatocytes. A high level of ADH was also observed in AFSP administered rats; on the other hand, a significant change in ALDH was not observed. Therefore, the SP can be a promising candidate in the prevention alcohol-induced hepatotoxicity and oxidative stress.

Tracing microplastics from raw water to drinking water treatment plants in Busan, South Korea.

The increasing amount of plastic waste has raised concerns about microplastics (MPs) in aquatic environments. MPs can be fragmented into nanoplastics that can pass through water treatment processes and into tap water; potentially threatening human health because of their high adsorption capacity for hazardous organic materials and their intrinsic toxicity. This case study investigates the identification, fate, and removal efficiency of MPs in Korean drinking water treatment plants. Two sites on the Nakdong River, two lake reservoirs (raw water sources), and four corresponding drinking water treatment plants were targeted to trace the amounts, types, and sizes of MPs throughout the treatment process. Monthly quantitative and qualitative analyses were conducted by chemical image mapping using micro-Fourier-transform infrared spectroscopy. MPs larger than 20 µm were detected, and their sizes and types were quantified using siMPle software. Overall, the number of MPs in the river sites (January to April and October to November) exceeded those in the reservoirs, but only slight differences in the number of MPs between rivers and lake reservoirs were detected from June to October. The annual average number of MPs in River A, B and Lack C and D was not distinctively different (2.65, 2.48, 2.46 and 1.87 particles/L, respectively). The majority of MPs found in raw waters were polyethylene (PE)/polypropylene (PP) (> 60%) and polyethylene terephthalate (PET)/poly(methyl methacrylate) (PMMA) (20%), in addition to polyamide (<10%) in the river and polystyrene (<10%) in the lake reservoirs. Approximately 70-80% of the MPs were removed by pre-ozonation/sedimentation; 81-88% of PE/PP was removed by this process. PET/PMMA was removed by filtration. Correlation of MPs with water quality parameters showed that the Mn concentration was moderately correlated with the MP abundance in rivers and lake reservoirs, excluding the lake with the lowest Mn concentration, while the total organic carbon was negatively correlated with the MP abundance in both rivers (A and B) and lake reservoir C.

Flavonoids from silkworm droppings and their promotional activities on heme oxygenase-1.

A new flavane glucoside, 7,2'-dihydroxy-8-hydroxyethyl-4'-methoxyflavane-2'-O-ß-d-glucopyranoside (3), along with three known flavonoids, 7,2'-dihydroxy-8-prenyl-4'-methoxyflavane (1), euchrenone a(7) (2), and 7,2'-dihydroxy-8-prenyl-4'-methoxy-2'-O-ß-d-glucopyranosylflavane (4), was isolated from silkworm droppings. The structures of the compounds were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and optical rotational characteristics. The compounds isolated from silkworm droppings were evaluated for their effects on heme oxygenase-1 (HO-1) activity. Compounds 1 and 3 increased the expression of HO-1 in HepG2 cells. HO-1 is an antioxidant enzyme that catabolizes heme to carbon monoxide, free iron, and biliverdin, all of which are involved in the suppression of inflammatory mediators.

Thirteen-week inhalation toxicity study of 1-propanol in F344 rats.

1-Propanol is a colorless volatile liquid at room temperature and is an important industrial alcohol. Workers are potentially exposed to it through inhalation during industrial activities, including manufacturing, sampling, filling, and mixing processes, as well as during cleaning, maintenance, and repair. Consequently, further information and/or testing for inhalation-related toxicological data is required to assess occupational risk. In this study, 80 (40 male and 40 female) F344 rats were exposed to 1-propanol vapors for 13 weeks (6 h a day, 5 days per week) at target concentrations of 0, 500, 1,600, and 5200 ppm in a whole-body inhalation chamber system. Clinical signs, mean body weight changes, food consumption, hematology, blood biochemistry, necropsy, organ weight, and histopathological findings were observed. The exposure concentrations in chambers were 501.30 ± 9.54 ppm, 1605.43 ± 66.55 ppm, and 5202.19 ± 102.74 ppm for the low, middle, and high dose groups, respectively. No changes related to 1-propanol were observed, including histopathological findings, except for mean body weight changes. The significant decrease in mean body weight at a high dose was not considered to be an adverse effect. Based on these results, the no observed adverse effect concentration of 1-propanol was estimated to be 5202.19 ppm.

Validation of a Korean version of the Moral Sensitivity Questionnaire.

The main purpose of this study was to validate a scale to examine the moral sensitivity of Korean nurses. A pre-existing scale, the Moral Sensitivity Questionnaire (MSQ), developed by Lützén, was used after deletion of three items. The reliability and validity of the scale were examined by using Cronbach's alpha and factor analysis, respectively. According to the results, reliability of the scale was adequate but its construct validity was not fully supported. Through discussion on evidence of validity, five subconstructs emerged. In particular, unlike the factor structure of the MSQ, two subconstructs, patient-oriented care and professional responsibility, were newly extracted. It was assumed that the other three MSQ subconstructs, conflict, meaning and benevolence (expressed as nurses being ethically good), would not be sensitive to cultural background. Given these findings, interpretations about the meaning of moral sensitivity of Korean nurses are discussed.

Four-week inhalation toxicity study of 1-propanol in F344 rats.

1-Propanol is used as a solvent for waxes, vegetable oils, resins, cellulose esters, and ethers, and is not considered harmful to humans by food and non-occupational exposures. However, workers are potentially exposed to 1-propanol by inhalation when it is used in the workplace. Thus, inhalation toxicity data are needed to assess the hazard of 1-propanol for workers safety. Five male and five female F344 rats were exposed to 1-propanol vapor for 4-weeks (6 h/day, 5 days/week) at concentrations of 0, 100, 400, and 1600 ppm in a whole-body inhalation chamber system. The actual exposure concentrations were 100.11 ± 5.10, 403.19 ± 12.31, and 1598.08 ± 139.58 ppm for the low, middle, and high dose groups, respectively. No clinical signs, significant mean body weight changes, significant changes of hematology or blood biochemistry results, or histopathological abnormalities were seen related to exposure to the test substance. Under the conditions of this study, the no-observed-adverse-effect level of 1-propanol was over 1600 ppm.

Thirteen-week inhalation toxicity study of 1-methylnaphthalene in F344 rats.

1-Methylnaphthalene is generally utilized in solvents, as an intermediate in organic synthesis, a dye carrier, in resins, and others. There are some toxicological studies of 1-methylnaphthalene; however, inhalation toxicity studies are rare. Each of 10 male and female F344 rats was exposed to vapors of 1-methylnaphthalene for 13 weeks (6 h a day, 5 days per week) at concentrations of 0, 0.5, 4, and 30 ppm in a whole-body inhalation chamber system. The exposure concentrations were 0.52 ± 0.05, 4.08 ± 0.25, and 30.83 ± 1.28 ppm for the low-, middle-, and high-dose group, respectively. Body weight changes were not affected by exposure to 1-methylnaphthalene. Blood prothrombin time was delayed at 30 ppm in male and female groups, and activated partial thromboplastin time was also delayed at 30 ppm in the male group. Values of alanine aminotransferase in the serum were decreased and those of albumin were increased at 30 ppm in the male group. Differential cell counts and levels of lactate dehydrogenase in the bronchoalveolar lavage fluid were not affected. However, mucous cell hyperplasia in the nasopharyngeal tissues was found and the severity was correlated to exposure concentrations. In conclusion, 1-methylnaphthalene mainly affects the upper respiratory system and the no-observed-adverse-effect level is suggested to be 4 ppm on the basis of histopathological findings.

Subacute Oral Toxicity Evaluation of Freeze-Dried Powder of Locusta migratoria.

Novel food sources have enormous potential as nutritional supplements. For instance, edible insects are considered as an alternative food source due to their higher protein content; moreover, they are economically efficient reproducers and have high in nutritional value. In this study, we investigated the toxicity of the freeze-dried powder of Locusta migratoria (fdLM), known to contain rich proteins as well as fatty acids. The objective of the present study was to evaluate the subacute toxicity of fdLM in male and female Sprague-Dawley (SD) rats. The SD rats were divided into four groups based on the dosage of fdLM administered: dosage of 0 (vehicle control), 750, 1,500, and 3,000 mg/kg/day were administered for 28 days. Toxicological assessments including observations on food consumption, body and organ weights, clinical signs, mortality, ophthalmologic tests, urinalyses, hematologic tests, clinical chemistry tests, gross findings, and histopathology tests were performed. Clinical signs, urinalyses, hematology, serum biochemistry tests, and organ weight examinations revealed no fdLM-related toxicity. The no-observed-adverse-effect level for fdLM was higher than 3,000 mg/kg/day in rats of both sexes; therefore, fdLM, in conclusion, can be considered safe as an edible alternative human and animal food source material.