Search results for "TOXICITY"
showing 10 items of 2261 documents
Toxicological Profile of Ultrapure 2,2´,3,4,4´,5,5´-Heptachlorbiphenyl (PCB 180) in Adult Rats
2014
PCB 180 is a persistent non-dioxin-like polychlorinated biphenyl (NDL-PCB) abundantly present in food and the environment. Risk characterization of NDL-PCBs is confounded by the presence of highly potent dioxin-like impurities. We used ultrapure PCB 180 to characterize its toxicity profile in a 28-day repeat dose toxicity study in young adult rats extended to cover endocrine and behavioral effects. Using a loading dose/maintenance dose regimen, groups of 5 males and 5 females were given total doses of 0, 3, 10, 30, 100, 300, 1000 or 1700 mg PCB 180/kg body weight by gavage. Dose-responses were analyzed using benchmark dose modeling based on dose and adipose tissue PCB concentrations. Body w…
Delivery of epirubicin via slow infusion as a strategy to mitigate chemotherapy-induced cardiotoxicity
2017
Background Continuous infusion of doxorubicin has been a strategy to reduce cardiotoxicity. Epirubicin is another anthracycline in common clinical use. However, evidence is lacking regarding whether this strategy can reduce cardiotoxicity of epirubicin without compromising antineoplastic efficacy. Design and methods Healthy rats were randomized into groups: epirubicin (8 mg/kg) delivered intraperitoneally via micro osmotic pumps (MOP), epirubicin (8 mg/kg) by intraperitoneal (IP) bolus injection, and placebo control. Blood samples were collected for analyzing biomarkers of myocardial injury and pharmacokinetics. At chosen times, sub-groups of animals were sacrificed for histopathology. A mo…
Why Women Have More Alzheimer's Disease Than Men: Gender and Mitochondrial Toxicity of Amyloid-β Peptide
2010
The main risk factors for developing Alzheimer's disease (AD) are age and gender. The incidence of the disease is higher in women than in men, and this cannot simply be attributed to the higher longevity of women versus men. Thus, there must be a specific pathogenic mechanism to explain the higher incidence of AD cases in women. In this regard, it is notable that mitochondria from young females are protected against amyloid-beta toxicity, generate less reactive oxygen species, and release less apoptogenic signals than those from males. However, all this advantage is lost in mitochondria from old females. Since estrogenic compounds protect against mitochondrial toxicity of amyloid-beta, estr…
Sodium metabisulfite as a cytotoxic food additive induces apoptosis in HFFF2 cells
2021
Sodium metabisulfite (SMB), an antioxidant agent, is extensively used as a preservative in food industry. The current study was aimed to clarify its potential toxic effects on human fetal foreskin fibroblasts (HFFF2) cells, in vitro. Subsequently, MTT results illustrated that exposure to SMB significantly (p 0.0001) decreased HFFF2 cell viability in a dose-dependent manner, and the concentration of 25 μM reduced cell survival rates to 50% as the half-maximal inhibitory concentration of SMB. It was further shown that SMB exerted this cytotoxic effect on HFFF2 cells through apoptosis induction. qRT-PCR and western blotting results showed that treatment of HFFF2 cells with this food additive …
Cocaine hepatotoxicity: two different toxicity mechanisms for phenobarbital-induced and non-induced rat hepatocytes.
1993
Abstract Hepatocytes isolated from both phenobarbital-induced and control rats were short-term cultured and exposed to cocaine (8–2000 μM) for varying times. Intracellular lactate dehydrogenase activity, free calcium levels ([Ca 2+ ] i ), reduced glutathione (GSH) and lipid peroxidation were investigated to evaluate the toxic effect of cocaine on hepatocytes. Cytochrome P450 induction by phenobarbital potentiated the in vitro cytotoxicity of cocaine by a factor of 13 (IC 50 = 84 μ M induced cells vs 1100 μM in non-induced cells). This difference in the susceptibility of the two types of hepatocytes to cocaine correlated well with the activity of cytochrome P450 2 B 1 2 . Rapid depletion of …
Nitric Oxide Mediates Natural Polyphenol-induced Bcl-2 Down-regulation and Activation of Cell Death in Metastatic B16 Melanoma
2007
Intravenous administration to mice of trans-pterostilbene (t-PTER; 3,5-dimethoxy-4'-hydroxystilbene) and quercetin (QUER; 3,3',4',5,6-pentahydroxyflavone), two structurally related and naturally occurring small polyphenols, inhibits metastatic growth of highly malignant B16 melanoma F10 (B16M-F10) cells. t-PTER and QUER inhibit bcl-2 expression in metastatic cells, which sensitizes them to vascular endothelium-induced cytotoxicity. However, the molecular mechanism(s) linking polyphenol signaling and bcl-2 expression are unknown. NO is a potential bioregulator of apoptosis with controversial effects on Bcl-2 regulation. Polyphenols may affect NO generation. Short-term exposure (60 min/day) t…
Dietary administration of high doses of pterostilbene and quercetin to mice is not toxic.
2009
The aim of this study is to evaluate possible harmful effects of high doses of t-pterostilbene (t-PTER) and quercetin (QUER) in Swiss mice. Mice were fed during 28 days at doses of 0, 30, 300, and 3000 mg/kg body weight/day of t-PTER, QUER, or a mixture of both, t-PTER + QUER, which are equivalent to 5, 50, and 500 times, respectively, the estimated mean human intake of these polyphenols (25 mg/day). Daily oral administration of QUER, t-PTER, or a mixture of both of them did not cause mortality during the experimental period. There were no differences in food and water consumption on sex. No significant body weight gain in the male or female groups was observed. Red blood cell number and th…
Blood metal levels after minimally invasive repair of pectus excavatum
2021
Abstract OBJECTIVES Minimally invasive repair of pectus excavatum (MIRPE) is the most popular surgical approach for paediatric patients with pectus excavatum. A substernal stainless still bar is inserted and left in place for 3 years and then removed. Our goal was to investigate blood metal levels after MIRPE and to correlate them with surgical details, such as the numbers of bars and stabilizers and the length of time the bar was in place. METHODS Blood levels of iron, chromium, manganese, molybdenum and nickel were analysed in 130 teenagers (108 boys and 22 girls) who had MIRPE using inductively coupled plasma mass spectrometry. A total of 62 patients were operated on using MIRPE (study…
Visible light (>395nm) causes micronuclei formation in mammalian cells without generation of cyclobutane pyrimidine dimers
2004
Solar radiation gives rise to DNA damage in mammalian cells not only directly by excitation of DNA, which generates predominantly pyrimidine dimers, but also indirectly by the excitation of endogenous photosensitizers, which causes oxidative DNA modifications. The latter mechanism has a low quantum yield, but it is the only one proceeding in the visible range of the spectrum. To investigate its relevance for the genotoxicity of sunlight, we have analysed the generation of micronuclei associated with the induction of oxidative DNA damage by visible light in melanoma cells and primary human skin fibroblasts. Similar yields of light-induced oxidative DNA base modifications sensitive to the rep…
Ethnobotanical survey and cytotoxicity testing of plants of South-western Nigeria used to treat cancer, with isolation of cytotoxic constituents from…
2010
Abstract Ethnopharmacological relevance There is only scant literature on the anticancer components of medicinal plants from Nigeria, yet traditional healers in the area under study claim to have been managing the disease in their patients with some success using the species studied. Aim of study To document plants commonly used to treat cancer in South-western Nigeria and to test the scientific basis of the claims using in vitro cytotoxicity tests. Methods Structured questionnaires were used to explore the ethnobotanical practices amongst the traditional healers. Methanol extracts of the most common species cited were screened for cytotoxicity using the sulforhodamine B (SRB) assay in both…