Publications by authors named "Ciro A Oliveira Ribeiro"

Many human activities contribute to the pollution of aquatic ecosystems, primarily through agricultural, industrial, mining, and domestic discharges into water bodies. Fish, being highly sensitive to environmental changes, serve as valuable models for monitoring the health of these ecosystems. Metallothionein (Mt), a biomarker for metal contamination, shows variable expression depending on the metal involved.

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Decabromodiphenyl ether (BDE-209) is a commonly used additive in plastics, primarily used as a flame retardant, and is classified as a persistent organic pollutant. Melanoma is the most aggressive type of skin cancer due to its high capacity for distant metastatic spread and high lethality. Therefore, the current study aimed to investigate the in vivo role of BDE-209 in the progression, malignancy and chemotherapy treatment of melanoma.

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Human activities contaminate aquatic ecosystems with chemicals like metals and pesticides. Fish, sensitive to pollution, are key toxicological models. Metallothionein (Mt) expression, a biomarker for metal contamination, varies depending on the chemical exposure.

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Pesticide use increases annually, and Brazil is the world's largest consumer. However, unlike the European Union (EU), there is no established limit value for pesticide mixtures in drinking water, and therefore the concentration of pesticides can reach 3354 times the EU limit. Thus, determining the risk of exposure to pesticide mixtures and their main metabolites is challenging and requires the use of alternative methods.

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Article Synopsis
  • The Iguaçu River basin has a unique fish population but is threatened by chemical pollution, especially from the Jordão River, which drains contaminated agricultural and industrial areas.
  • A study found that while most contaminants were within Brazilian legal limits, cadmium, aluminum, and lead were found at harmful levels in certain locations, affecting fish embryos and larvae.
  • The research demonstrates that even low-level pollutants can increase mortality and deformity rates in aquatic organisms, highlighting the need for conservation efforts to protect local wildlife and maintain ecological health.
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Environmental contaminants, such as polycyclic aromatic hydrocarbons (PAHs), have raised concerns regarding their potential endocrine-disrupting effects on aquatic organisms, including fish. In this study, molecular docking and molecular dynamics techniques were employed to evaluate the endocrine-disrupting potential of PAHs in zebrafish, as a model organism. A virtual screening with 72 PAHs revealed a correlation between the number of PAH aromatic rings and their binding affinity to proteins involved in endocrine regulation.

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This study investigated the impact of micropollutants on fish health from Segredo hydroelectric reservoir (HRS) along the Iguaçu River, Southern Brazil, contaminated by urban, industrial, and agricultural activities. This is the first comprehensive study assessment in the river after the severe drought in the 2020s in three fish species from different trophic levels Astyanax spp. (water column depth/omnivorous), Hypostomus commersoni (demersal/herbivorous), and Pimelodus maculatus (demersal/omnivorous).

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Pesticides are contaminants run-offs from agricultural areas with a global concern due to their toxicity for non-target organisms. The Brazilian Health Surveillance Agency reported about 63% of the food contain pesticide residues. Glyphosate is a herbicide used worldwide but its toxicity is not a consensus among specialists around the world.

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The 2,4-Dichlorophenoxyacetic acid (2,4-D) is a low-cost herbicide to eradicate broadleaf weeds. Since the development of 2,4-D resistant transgenic crops, it has been described as one of the most widely distributed pollutants in the world, increasing concern about its environmental impacts. This study aimed to elucidate the antioxidant system response in animals exposed to 2,4-D by different routes of exposure.

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Melanoma is a type of skin cancer considered aggressive due to its high metastatic ability and rapid progression to other tissues and organs. BDE-209 (2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether) is an additive used as a flame retardant and classified as a persistent organic pollutant that has a high bioaccumulation capacity due to its lipophilic nature. This substance has already been detected in rivers, air, soil, plants and even in different human biological samples, such as plasma, umbilical cord blood and breast milk, revealing a great concern to human populations.

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Bioaccumulation studies in fish mark the initial phase of assessing the risk of chemical exposure to biota and human populations. The Iguaçu River boasting a diverse endemic ichthyofauna, is grappling with the repercussions of human activities. This study delved into the bioaccumulation of micropollutants, the early-warning effects on Rhamdia quelen and Oreochomis niloticus in the Segredo Reservoir (HRS) and the potential risk of human exposure.

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This study aimed to evaluate glyphosate (GLY) and aminomethylphosphonic acid (AMPA) toxicity at 65, 650, and 6500 μg L to the initial stages of development of Steindachneridion melanodermatum, an endangered endemic species from the Iguaçu River, assessing hatching, survival, total larval length, deformities, oxidative stress biochemical biomarkers, and neurotoxicity. Overall, looking at the sum of responses through the integrated biomarker response, the species was more sensitive to AMPA than GLY, especially at the lower concentration of 65 μg L, which induced mortality, deformities, underdevelopment, and oxidative stress. Considering the risk of exposure and the importance of conservation of the highly endemic ichthyofauna of this basin, it is urgent to investigate and regulate both GLY and AMPA levels at the Iguaçu River to protect not only this species, but the entire ecosystem.

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Pesticides are used to combat agricultural pests but also trigger side effects on non-target organisms. Particularly, immune system dysregulation is a major concern due to the organism's increased vulnerability to diseases, including cancer development. Macrophages play essential roles in innate and adaptive immunity and can undergo classical (M1) or alternative (M2) activation.

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Pesticides use increased worldwide with a record in Brazil. Although several works addressed the effects of pesticides on living organisms, only a few considered their mixture, and even fewer tried to unravel their role in tumoral progression. Due to the relevance of cancer, in the present study, the effects of the mixture of pesticides widely used in Brazil (Glyphosate, 2,4-dichlorophenoxyacetic acid, Mancozeb, Atrazine, Acephate, and Paraquat) and their main metabolites (Aminomethylphosphonic Acid, 2,4-diclorophenol, Ethylenethiourea, Desethylatrazine, Methamidophos, and Paraquat) were investigated on the malignancy phenotype of murine melanoma B16-F1 cells after acute (24 h) and chronic (15 days) exposures.

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Aquatic biota is increasingly being exposed to chemical pollutants due to human activities and the relationship between the level of environmental pollution and fish reproduction is a continuously ongoing issue. The vitellogenin (Vtg) protein synthesis can be induced in the liver of juvenile and male fish after stimulation of the estrogen receptor and therefore, Vtg has been used as a biomarker of xenoestrogen exposure in several fish species. The current study reported the first physicochemical characterization of Vtg from Oreochromis niloticus.

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PBDEs are toxic, lipophilic, hydrophobic, and persistent artificial chemicals, characterized by high physical and chemical stability. Although PBDEs are known to disturb hormone signaling, many effects of 2,2',4,4',5 - pentain polybrominated diphenyl ethers (BDE-99) in fish remain unclear. The current study investigates the effects of BDE-99 in Oreochromis niloticus where sixty-four juvenile fish were orally exposed to 0.

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TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and BDE-209 (decabromodiphenyl ether) are persistent organic pollutants (POPs) produced by industrial activities and associated with several diseases. TCDD is a known human carcinogen, but few studies investigated about the effects of exposure to both compounds, i.e.

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Article Synopsis
  • The study highlights the drawback of simplifying complex histopathological data into single indices, which can result in significant information loss regarding environmental quality.
  • The research aimed to assess the effectiveness of a multivariate approach that combines individual histopathological responses with contaminant levels, comparing it to the traditional univariate Bernet index.
  • Results showed that the multivariate analysis provided a clearer classification of environmental quality across various sites, while the univariate index was less reliable and primarily identified only the most severely impacted areas.
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Chronic exposure to multiple pollutants affects aquatic organisms, even at low concentrations, and can impair fishery activities along marine coastlines. The bioavailability of toxic metals and the presence of metals and polycyclic aromatic hydrocarbons (PAHs) in both water and sediment can explain the worst-case scenario of fish health and fishery production decline along the Algeria coastline. The hepatosomatic index (HIS), gonadosomatic index (GSI), and condition factor (K) in the studied species from the Algiers, Bou Ismail, and Zemmouri bays are the first indicators of the poor environmental health along the studied region.

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The Iguaçu River basin presents high ecological importance due to its expressive endemic ichthyofauna rate, but chemical pollution may threat this biodiversity. Jordão River is one of the main tributaries of Iguaçu River and contribute to this pollution status, since it drains large agricultural areas receiving domestic and industrial effluents before flowing into the Iguaçu River. The objective of the current study was to evaluate the toxic effects of the Iguaçu, Jordão, and the combination of their waters to the embryo-larval phase of R.

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Flame retardants are compounds added to a high diversity of polymers used in electronics and furniture to decrease the risk of combustion. Decabromodiphenyl ether (BDE-209) is a polybrominated diphenyl ether (PBDE) congener still used worldwide, while 2, 4, 6-tribromophenol(TBP) is a PBDE metabolite used as a pesticide and flame retardant for wood conservation. These compounds have lipophilic properties and are easily bioaccumulated in the food chain.

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Cancer is one of the leading causes of mortality worldwide. Even with the advances of pharmaceutical industry and treatments, the mortality rate for various types of cancer remains high. In particular, phenotypic alterations of tumor cells concerning drug efflux, migratory and invasive capabilities may represent a hurdle for cancer treatment and contribute to poor prognosis.

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Background: Silver nanoparticles (AgNP) are largely used in nanotechnological products, but the real risks for human and environment are still poorly understood if we consider the effects of mixtures of AgNP and environmental contaminants, such as non-essential metals.

Methods: The aim of the present study was to investigate the cytotoxicity and toxicological interaction of AgNP (1-4 nm, 0.36 and 3.

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Article Synopsis
  • Polybrominated diphenyl esters, like BDE-47, are new environmental contaminants that raise concerns due to limited toxicological data, prompting this study on their effects on the fish species Oreochromis niloticus.
  • The study exposed fish to various BDE-47 doses over 80 days, finding that these exposures impacted liver and reproductive health, hormone levels, and enzyme activity across different dosages.
  • The results indicate that low doses of BDE-47 can be toxic to this fish species and highlight the importance of using multiple biomarkers in ecotoxicology research and environmental monitoring.
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Urban sewage is a source of major contamination in aquatic systems and contributes to environmental and human health disturbances. This study investigates the effects of sewage-polluted waters from Iguaçu River on the health of juvenile Oreochromis niloticus. Two hundred four specimens were exposed to riverine water in four groups: no diluted, 25 and 50 % diluted water and a control group without tested water for 72 days.

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