Induction and repression effects on CYP and transporter protein abundance by azole mixture uptake in rat liver.

Detection of mixture effects is a major challenge in current experimental and regulatory toxicology. Robust markers are needed that are easy to quantify and responsive to chemical stressors in a broad dose range. Several hepatic enzymes and proteins related to drug metabolism like cytochrome-P-450 (CYP) enzymes and transporters have been shown to be responsive to pesticide active substances in a broad dose range and are therefore good candidates to be used as markers for mixture toxicity. Even though they can be well quantified at the mRNA level, quantification on the protein level is challenging because most of these proteins are membrane bound. Here we report the development of mass spectrometry-based assays using triple-x-proteomics (TXP) antibodies in combination with targeted selected ion monitoring (tSIM) to quantify changes of protein levels due to exposure to mixtures of pesticide active substances. Our results indicate that changes on the protein level of CYP1A1, ABCB2, ABCC3 are in line with observations on the mRNA and enzyme activity level and are indicative of mixture effects. Therefore, the tests are promising to reveal effects by chemical mixture effects in toxicological studies in rats.

Estratégias de coordenação governamental na Crise da Covid-19 / Português

O objetivo deste texto é apresentar, com base na literatura existente e no acúmulo de pesquisas realizadas no Ipea sobre o tema, uma sugestão de um arranjo institucional de coordenação governamental que possa contribuir para um melhor desempenho das ações adotadas pelo governo brasileiro neste momento. Além desta introdução e das considerações finais, o texto está dividido em outras seções. A próxima reúne algumas contribuições da literatura sobre a atuação governamental em situações de crise. Na terceira seção são discutidos alguns determinantes de sucesso da coordenação governamental aplicáveis ao contexto atual. Em seguida, apresenta-se uma proposta de atuação organizada em frentes de ação para viabilizar a atuação do Estado brasileiro diante da pandemia em curso.

O enfermeiro e a criança: a prática do brincar e do brinquedo terapêutico durante a hospitalização / The nurse and the child: therapeutic toy and the practice of playing during hospitalization

Objetivou-se identificar o conhecimento dos enfermeiros quanto à prática do brincar e do Brinquedo Terapêutico na hospitalização da criança. Estudo descritivo com abordagem qualitativa, realizado com 10 enfermeiros que atuam em um hospital público infantil no Norte de Santa Catarina, por meio de uma entrevista semiestruturada, no ano de 2018. Os dados foram analisados conforme o método da análise temática. Emergiram quatro categorias temáticas: o brincar e o enfermeiro; o brincar como parte do tratamento; o brincar em um ambiente favorável; a abordagem do enfermeiro e o uso do brinquedo/Brinquedo Terapêutico. Os resultados mostram que os enfermeiros reconhecem a importância do brincar durante a hospitalização da criança, considerado uma forma de aproximação com o infante. Verifica-se também o desconhecimento dos enfermeiros em relação à tecnologia do uso do Brinquedo Terapêutico durante a hospitalização como uma ferramenta de cuidados da enfermagem. Ressalta-se a importância da abordagem deste conteúdo nos cursos de graduação em enfermagem, especialização e residência em enfermagem pediátrica e a realização de cursos de capacitação para os profissionais da prática assistencial (AU)

The objective of this study was to identify nurses' knowledge regarding the practice of playing and Therapeutic Toy in the hospitalization of children. Descriptive study with qualitative approach, conducted with ten nurses who work in a public children's hospital in northern Santa Catarina through a semi-structured interview, in 2018. The data were analyzed according to the thematic analysis method. Four thematic categories emerged: play and the nurse; play as part of treatment; play in a favorable environment; the nurse's approach and the use of the toy/Therapeutic Toy. The results show that nurses recognize the importance of playing during the child's hospitalization, considered a way of approaching the infant. Nurses' lack of knowledge regarding the technology of the use of the Therapeutic Toy during hospitalization as a nursing care tool is also verified. We emphasize the importance of addressing this content in undergraduate nursing, specialization and residency courses in pediatric nursing and conducting training courses for healthcare professionals (AU)

Estratégias de coordenação governamental na crise da Covid-19 / Nota Técnica n. 32 (Diest) : Estratégias de coordenação governamental na crise da Covid-19

Esta nota técnica apresenta uma sugestão, com base na literatura existente e no acúmulo de pesquisas realizadas no Ipea sobre o tema, de um arranjo institucional de coordenação governamental que pode contribuir para um melhor desempenho das ações adotadas pelo governo brasileiro nesse momento. A nota faz parte de um conjunto de documentos elaborados pelo Ipea buscando garantir, em um momento crítico e de potencial inflexão para a trajetória nacional de desenvolvimento, subsídios, propostas e evidências robustas e objetivas para o país.

Assessment of mixture toxicity of (tri)azoles and their hepatotoxic effects in vitro by means of omics technologies.

Consumers are constantly exposed to chemical mixtures such as multiple residues of different pesticides via the diet. This raises questions concerning potential combination effects, especially because these substances are tested for regulatory purposes on an individual basis. With approximately 500 active substances approved as pesticides, there are too many possible combinations to be tested in standard animal experiments generally requested for regulatory purposes. Therefore, the development of in vitro tools and alternative testing strategies for the assessment of mixture effects is extremely important. As a first step in the development of such in vitro tools, we used (tri)azoles as model substances in a set of different cell lines derived from the primary target organ of these substances, the liver (human: HepaRG, rat: H4IIE). Concentrations were reconciled with measured tissue concentrations obtained from in vivo experiments to ensure comparable effect levels. The effects of the substances were subsequently analyzed by transcriptomics and metabolomics techniques and compared to data from corresponding in vivo studies. The results show that similar toxicity pathways are affected by substances and combinations, thus indicating a similar mode of action and additive effects. Two biomarkers obtained by the approach, CAR and Cyp1A1, were used for mixture toxicity modeling and confirmed the concentration-additive effects, thus supporting the selected testing strategy and raising hope for the development of in vitro methods suitable to detect combination effects and prioritize mixtures of concern for further testing.

Unexpected Effects of Propiconazole, Tebuconazole, and Their Mixture on the Receptors CAR and PXR in Human Liver Cells.

Analyzing mixture toxicity requires an in-depth understanding of the mechanisms of action of its individual components. Substances with the same target organ, same toxic effect and same mode of action (MoA) are believed to cause additive effects, whereas substances with different MoAs are assumed to act independently. Here, we tested 2 triazole fungicides, propiconazole, and tebuconazole (Te), for individual and combined effects on liver toxicity-related endpoints. Both triazoles are proposed to belong to the same cumulative assessment group and are therefore thought to display similar and additive behavior. Our data show that Te is an antagonist of the constitutive androstane receptor (CAR) in rats and humans, while propiconazole is an agonist of this receptor. Both substances activate the pregnane X-receptor (PXR) and further induce mRNA expression of CYP3A4. CYP3A4 enzyme activity, however, is inhibited by propiconazole. For common targets of PXR and CAR, the activation of PXR by Te overrides CAR inhibition. In summary, propiconazole and Te affect different hepatotoxicity-relevant cellular targets and, depending on the individual endpoint analyzed, act via similar or dissimilar mechanisms. The use of molecular data based on research in human cell systems extends the picture to refine cumulative assessment group grouping and substantially contributes to the understanding of mixture effects of chemicals in biological systems.

Hepatotoxic effects of cyproconazole and prochloraz in wild-type and hCAR/hPXR mice.

The agricultural fungicides cyproconazole and prochloraz exhibit hepatotoxicity in rodent studies and are tumorigenic following chronic exposure. Both substances are suspected to act via a CAR (constitutive androstane receptor)/PXR (pregnane-X-receptor)-dependent mechanism. Human relevance of these findings is under debate. A 28-day toxicity study was conducted in mice with humanized CAR and PXR (hCAR/hPXR) with two dose levels (50 or 500 ppm) of both substances, using the model CAR activator phenobarbital as a reference. Results were compared to wild-type mice. A treatment-related increase in liver weights was observed for all three substances at least at the high-dose level. Changes in the expression of classic CAR/PXR target genes such as Cyp2b10 were induced by cyproconazole and phenobarbital in both genotypes, while prochloraz treatment resulted in gene expression changes indicative of additional aryl hydrocarbon receptor activation, e.g. by up-regulation of Cyp1a1 expression. Cyproconazole-induced effects on CAR-dependent gene expression, liver weight, and hepatic lipid accumulation were more prominent in wild-type mice, where significant genotype differences were observed at the high-dose level. Moreover, high-dose cyproconazole-treated mice from the wild-type group responded with a marked increase in hepatocellular proliferation, while hCAR/hPXR mice did not. In conclusion, our data demonstrate that cyproconazole and PB induce CAR/PXR downstream effects in hepatocytes in vivo via both, the murine and human receptors. At high doses of cyproconazole, however, the responses were clearly more pronounced in wild-type mice, indicating increased sensitivity of rodents to CAR agonist-induced effects in hepatocytes.

Effects of mycophenolic acid alone and in combination with its metabolite mycophenolic acid glucuronide on rat embryos in vitro.

Mycophenolic acid (MPA) is an immunosuppressive agent that acts as a selective, non-reversible inhibitor of the enzyme inosine-5'-monophosphate dehydrogenase (IMPDH). Malformations have been described in children after maternal exposure to mycophenolate. However, the causal link is unclear in most cases because women had been treated with a combination of drugs and birth defects may have other causes. Therefore, it is important to study the action of this drug and its main metabolite on embryonic tissue. We studied the teratogenic potential of MPA and its major metabolite, the mycophenolic acid glucuronide (MPAG) in the rat whole-embryo culture. A total of 147 day 9.5 embryos were cultivated for 48 h in the standard medium containing 85 % serum. We tested MPA at concentrations of 0.1; 0.25; 0.5; 0.75 mg/l (0.31; 0.78; 1.56; 2.34 µM) and MPA glucuronide at concentrations of 3; 10; 30; 100 mg/l (6.04; 20.14; 60.43; 201.43 µM). Both substances are highly protein bound, and MPA glucuronide might displace MPA from protein binding. Therefore, we examined whether the effects of MPA can be enhanced when studied in combination with the glucuronide. Furthermore, the focus was on additional endpoints to the standard evaluation of cultivated embryos, such as development of cranial nerves [trigeminal nerve (V), facial nerve (VII), glossopharyngeal nerve (IX), vagus nerve (X)] after staining with an antibody against 2H3 neurofilament. Ultrastructural changes were evaluated by electron microscopy. At a concentration of 0.75 mg MPA/l medium, all embryos showed dysmorphic changes. Embryos exposed to 0.25 mg MPA/l medium showed impaired development of nerves, and at 0.1 mg/l, no effects were detectable. Concentration-dependent ultrastructural changes, such as signs of apoptosis, were found by electron microscopy. The examination of the metabolite in this assay showed that at a concentration of 100 mg MPAG/l, the embryos exhibited distinct malformations. This is probably caused by MPA, which was detectable at 0.6 % in the material used for our experiments. The combination of the parent compound (0.03; 0.1; 0.25 mg/l) with its metabolite MPAG (3 mg/l) did not cause enhanced toxicity under our experimental conditions. IMPDH, the target enzyme of MPA, could be detected in rat embryos on day 9.5 of embryonic development as well as at the end of the culture period 48 h later. In summary, MPA impairs embryonic development at low, therapeutically relevant concentrations, but the glucuronide does not exhibit such a potential. Activity of MPA is not enhanced by MPAG.