Fernanda Marlen Enríquez-Sánchez, Miguel Ángel López-Vázquez, María Esther Olvera-Cortés, Liliana Valdez-Jiménez, Paola Trinidad Villalobos-Gutiérrez, María Isabel Pérez-Vega
{"title":"Effect of Chronic Consumption of Fluoridated Water on Sciatic Nerve Conduction Velocity in Male <i>Wistar</i> Rats.","authors":"Fernanda Marlen Enríquez-Sánchez, Miguel Ángel López-Vázquez, María Esther Olvera-Cortés, Liliana Valdez-Jiménez, Paola Trinidad Villalobos-Gutiérrez, María Isabel Pérez-Vega","doi":"10.1177/10915818241297082","DOIUrl":"10.1177/10915818241297082","url":null,"abstract":"<p><p>The long-term effect of fluoridated water consumption during development on the velocity of nerve impulse conduction in the sciatic nerve of rats was assessed. Thirty male Wistar rats, 21 days old, were randomly assigned to five groups. Three groups were given fluoridated water ad libitum (as the only source) at different concentrations (10, 100, and 150 ppm), designated as groups F10, F100, and F150, respectively. The study included a control group (C) that received fluoridated water at the maximum level established by the World Health Organization (1.5 ppm of fluorides) and another group that received deionized water (DW). The animals were treated until they reached 90 days of age. Electrophysiological recordings were performed on the rats' sciatic nerves to determine nerve conduction velocity, and blood plasma was extracted for fluoride concentration analysis. The study found that the F150 group had a lower nerve impulse conduction velocity in the sciatic nerve compared to the C group (<i>P</i> = 0.0015). Additionally, there was a negative correlation between the concentration of fluorides in plasma and the nerve conduction velocity (r = -0.5132, <i>P</i> = 0.0037). These findings indicate that chronic consumption of high concentrations of fluoride leads to a decrease in nerve conduction velocity. This, in conjunction with potential alterations in the central nervous system, may explain the deficits in learning and memory tests that have been documented in numerous studies evaluating individuals exposed to fluoride consumption. These results provide valuable information for understanding the effects and action mechanisms of fluoride in exposed individuals.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"39-45"},"PeriodicalIF":1.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142583192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Effects of Nanoplastics on the Dopamine System of Cerebrocortical Neurons.","authors":"Na-Hyun Kim, Young-A Lee","doi":"10.1177/10915818241293993","DOIUrl":"10.1177/10915818241293993","url":null,"abstract":"<p><p>Nanoplastics (NPx) can enter living organisms, including humans, through ecosystems, inhalation, and dermal contact and can be found from the intestine to the brain. However, it is unclear whether NPx accumulates and affects the dopamine system. In this study, we investigated the effects of NPx on the dopamine system in cultured murine cerebral cortex neurons. Cultured cerebrocortical neurons were treated with 100 nm NPx at the following concentrations for 24 h: 1.896 × 10<sup>5</sup>, 3.791 × 10<sup>6</sup>, 7.583 × 10<sup>7</sup>, 1.571 × 10<sup>9</sup>, 3.033 × 10<sup>10</sup>, and 3.033 × 10<sup>11</sup> particles/mL. Dopamine-associated proteins were analyzed using immunofluorescence staining. NPx treatment induced its accumulation in neurons in a dose-dependent manner and increased the levels of dopamine receptors D1 and D2 and their co-expression. However, NPx treatment did not affect the levels of other dopamine receptors, dopamine transporters, tyrosine hydroxylase, and microtubule-associated protein 2, or synaptophysin in neuronal structures. This study demonstrated that NPx is a potential modulator of the dopamine system via its receptors rather than its synthesis and reuptake in neurons and may be associated with dopamine-based psychiatric disorders.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"29-38"},"PeriodicalIF":1.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142564206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Thank you to our ad hoc reviewers!","authors":"","doi":"10.1177/10915818241306311","DOIUrl":"https://doi.org/10.1177/10915818241306311","url":null,"abstract":"","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":"44 1","pages":"88"},"PeriodicalIF":1.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142970714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Inclusion of Histopathology in Dose Range-Finding Nonclinical Studies for Inhaled Drug Products.","authors":"Emily A Resseguie, Helen Palmer","doi":"10.1177/10915818241276439","DOIUrl":"10.1177/10915818241276439","url":null,"abstract":"<p><p>Drug development is a lengthy process that promotes and protects the health and safety of future patients. Nonclinical safety studies follow essentially similar designs that fulfill regulatory requirements but are amended based on factors including the mechanism of action, class of molecule, and route of administration. Clinical observations, clinical pathology, and macroscopic pathology in dose range-finding (DRF) studies generally provide sufficient information to select doses for pivotal studies by most delivery routes. Inhaled drug candidates are recognized for producing adverse effects on the respiratory system at the microscopic level that may otherwise be unpredictable; therefore, unlike other routes of administration, inhalation DRF studies typically include histopathology of the respiratory tract. Histopathology evaluations can add several weeks to the Investigational New Drug (IND) application timeline along with additional costs but have been considered necessary to support accurate dose selection for adequate safety margins, thereby potentially avoiding additional studies and animal usage by ensuring achievement of a NOAEL in the pivotal studies. Therefore, DRF inhalation studies initiated from 2018 to 2021 at Labcorp were reviewed to determine whether inclusion of histopathology on preliminary inhalation studies was necessary for subsequent dose selection. Histopathology findings in the DRF impacted dose selection in pivotal inhalation studies for approximately 45% of rat and dog studies. This review identified histopathology findings in rat and dog that support continued inclusion of respiratory tract histopathology in DRF studies. Future investigations will evaluate potential surrogate endpoints for these findings, which could reduce nonclinical drug development timelines by several weeks.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"540-548"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142107455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Twelfth Triennial Toxicology Salary Survey.","authors":"Shayne C Gad, Dexter Sullivan, Danika A Pitts","doi":"10.1177/10915818241284800","DOIUrl":"10.1177/10915818241284800","url":null,"abstract":"<p><p>This is the 12th in a series of salary surveys conducted at approximately 3-year intervals for toxicologists that began in 1988. Previous salary surveys were conducted in 1988,<sup>1</sup> 1991,<sup>2</sup> 1995,<sup>3</sup> 1998,<sup>4</sup> 2001,<sup>5</sup> 2004,<sup>6</sup> 2007 (which was posted electronically, but not published), 2012,<sup>7</sup> 2016,<sup>8</sup> 2020,<sup>9</sup> and 2022.<sup>10</sup> In addition to presenting the 2024 results, herein we are providing additional data and an analysis of the trends for employment and pay in toxicology over the last 37 years.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"520-539"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11740389/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142346704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elijah Finn, Lucia Dussan, Scott Rosenthal, Cynthia Simbulan-Rosenthal, Dean Rosenthal, Peter Sykora
{"title":"Temperature Is a Key Factor Governing the Toxic Impact of Ultra-Violet Radiation-Emitting Nail Dryers When Used on Human Skin Cells.","authors":"Elijah Finn, Lucia Dussan, Scott Rosenthal, Cynthia Simbulan-Rosenthal, Dean Rosenthal, Peter Sykora","doi":"10.1177/10915818241268617","DOIUrl":"10.1177/10915818241268617","url":null,"abstract":"<p><p>The skin is the largest organ in the body and the only one to come into contact with solar UV radiation (UVR). UVA (320-400 nm) is a significant contributor to UV-related skin damage. The UVA spectrum makes up over 95% of solar-UV energy reaching the earth's surface causing the majority of the visible signs of skin photoaging. Many consumer products also emit UVA, including nail dryers. There have been sporadic reports suggesting that these units may be contributing to skin cancer incidence. This notion was recently bolstered by a finding that nail dryer-irradiated mammalian skin cells develop a mutational signature consistent with UVA exposure. This report was surprising considering the comparatively low level of UVA to which the skin is exposed during nail treatments. In this research, we investigated how UVA-emitting devices caused cytotoxic/genotoxic impact after only low levels of UVA exposure. Our data showed that levels of UVA in the unit are highly variable and location dependent. We confirm previous reports that using prolonged exposure protocols could induce significant levels of DNA damage. It was also determined that UV-induced DNA damage only partially correlated with the level of UVA fluency. On investigation, we found that the unit had a rapid increase in internal temperature when in use. Exposing human cells to these elevated temperatures acted synergistically with UVA to magnify the cytotoxic and genotoxic impact of UV irradiation.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"549-560"},"PeriodicalIF":1.2,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11560569/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141889226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wilbur Johnson, Wilma F Bergfeld, Donald V Belsito, Ronald A Hill, Curtis D Klaassen, Daniel C Liebler, James G Marks, Ronald C Shank, Thomas J Slaga, Paul W Snyder, Monice Fiume, Bart Heldreth
{"title":"Safety Assessment of Alkanoyl Lactyl Lactate Salts as Used in Cosmetics.","authors":"Wilbur Johnson, Wilma F Bergfeld, Donald V Belsito, Ronald A Hill, Curtis D Klaassen, Daniel C Liebler, James G Marks, Ronald C Shank, Thomas J Slaga, Paul W Snyder, Monice Fiume, Bart Heldreth","doi":"10.1177/10915818241259694","DOIUrl":"10.1177/10915818241259694","url":null,"abstract":"<p><p>The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 10 alkanoyl lactyl lactate salts. These ingredients have the surfactant function in cosmetics in common. The Panel reviewed data relevant to the safety of these ingredients, and concluded that these 10 ingredients are safe in cosmetics in the present practices of use and concentration described in the safety assessment when formulated to be nonirritating and nonsensitizing, which may be based on a quantitative risk assessment (QRA) or other accepted methodologies.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"108-129"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141748101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wilbur Johnson, Wilma F Bergfeld, Donald V Belsito, Ronald A Hill, Curtis D Klaassen, Daniel C Liebler, James G Marks, Ronald C Shank, Thomas J Slaga, Paul W Snyder, Monice Fiume, Bart Heldreth
{"title":"Safety Assessment of Polyol Phosphates as Used in Cosmetics.","authors":"Wilbur Johnson, Wilma F Bergfeld, Donald V Belsito, Ronald A Hill, Curtis D Klaassen, Daniel C Liebler, James G Marks, Ronald C Shank, Thomas J Slaga, Paul W Snyder, Monice Fiume, Bart Heldreth","doi":"10.1177/10915818241259699","DOIUrl":"10.1177/10915818241259699","url":null,"abstract":"<p><p>The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 10 polyol phosphates. Some of the possible functions in cosmetics that are reported for this ingredient group are chelating agents, oral care agents, and skin conditioning agents. The Panel reviewed relevant data relating to the safety of these ingredients under the intended conditions of use in cosmetic formulations, and concluded that Sodium Phytate, Phytic Acid, Phytin, and Trisodium Inositol Triphosphate are safe in cosmetics in the present practices of use and concentration described in the safety assessment. The Panel also concluded that the data are insufficient to determine the safety of the following 6 ingredients as used in cosmetics: Disodium Glucose Phosphate, Manganese Fructose Diphosphate, Sodium Mannose Phosphate, Trisodium Fructose Diphosphate, Xylityl Phosphate, and Zinc Fructose Diphosphate.</p>","PeriodicalId":14432,"journal":{"name":"International Journal of Toxicology","volume":" ","pages":"78-107"},"PeriodicalIF":1.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141751712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}