Resumo O cancro do fígado é, globalmente, a terceira causa de morte por cancro. O carcinoma hepatocelular (CHC) desenvolve-se em doentes com doença hepática crónica subjacente. A fracção de CHC atribuível ao fígado gordo não alcoólico (FGNA) tem vindo a aumentar com uma aceleração no seu crescimento nas últimas décadas, sendo atualmente responsável por 15% dos casos de CHC. À semelhança do que ocorre com outras causas de cirrose hepática, os doentes com cirrose associada a FGNA devem ser inseridos em programas de rastreio de CHC. Contudo, esses doentes são sub-rastreados, já que a probabilidade de serem incluídos em programas de rastreio de CHC é menos de metade comparando com doentes com cirrose associada a hepatite C crónica. O CHC associado ao FGNA tem a particularidade de ocorrer em fases pré-cirróticas em 20 a 50% dos casos. O rastreio de CHC em doentes com FGNA em fase pré-cirrótica não está recomendado por rotina, uma vez que, ainda assim, o risco destes doentes desenvolverem CHC é muito baixo. No entanto, uma vez que um terço da população mundial tem FGNA, o FGNA em não cirróticos corresponde a 6%de todos os casos de CHC. Assim sendo, é urgente o desenvolvimento de métodos de estratificação, por forma a personalizar o risco individual de desenvolvimento de CHC em doentes com FGNA, permitindo maior precisão nos programas de rastreio de CHC. Esta revisão sumariza a epidemiologia de CHC associado ao FGNA, com uma análise crítica das atuais recomendações de rastreio de CHC.

Abstract Liver cancer is globally the third leading cause of death from cancer. Hepatocellular carcinoma (HCC) develops in patients with underlying liver disease. The fraction of HCC attributed to nonalcoholic fatty liver disease (NAFLD) shows an accelerated increase in the last decades, being already responsible for 15% of all HCC cases. Similar to other causes of liver cirrhosis, patients with NAFLD-associated cirrhosis should be enrolled in HCC-screening programs, yet these patients are underscreened, and currently are less than half likely to be proposed for HCC screening as compared to patients with HCV-associated cirrhosis. NAFLD-associated HCC has the peculiarity of occurring in precirrhotic phases in 20-50%of the cases. Currently, HCC screening in precirrhotic NAFLD patients is not routinely recommended, since the risk of developing HCC is very low. However, because NAFLD affects one-third of the worldwide population, noncirrhotic NAFLD already accounts for 6% of HCC cases. As such, it is pressing to develop stratification tools, in order to personalize the individual risk of HCC development in a patient with NAFLD, allowing precision HCC-screening programs. This review summarizes the epidemiology of NAFLD-associated HCC with a critical analysis of current HCC-screening recommendations.

Abstract Our aim was to evaluate the effects of cisplatin and dexamethasone alone and combined on gastric contractility and histomorphometry of BALB/c and C57BL/6 mice. BALB/c and C57BL/6 male mice (8-week-old) were randomly separated into: Control; Cisplatin (7.5 mg/Kg); Dexamethasone (2.0 mg/Kg); and Dexamethasone plus Cisplatin (2.0 mg/Kg of dexamethasone 1-hour prior to 7.5 mg/Kg of cisplatin). Drugs were administered intraperitoneally for three days. Body weight and food intake were evaluated on 2nd day. Alternating Current Biosusceptometry technique was employed to measure gastric contractions on 3rd day. Afterward, mice were killed for gastric histomorphometric analysis. Cisplatin decreased food intake and caused bradygastria in BALB/c mice; however, the amplitude of gastric contractions decreased in both BALB/c and C57BL/6. Dexamethasone and cisplatin combined restored the gastric frequency and food intake only in BALB/c, but drug combination reduced the gastric amplitude of contractions in both strains. Dexamethasone alone increased gastric mucosa thickness in C57BL/6 and decreased muscular thickness in BALB/c. In conclusion, the mouse strains presented differences in acute effects of cisplatin and dexamethasone alone and combined on gastric function. This reinforces the importance of choosing the appropriate mouse strain for studying the acute effects of drugs on the gastrointestinal tract.

Abstract emotional regulation in adolescents is an aspect little observed, especially by researchers and health professionals in Brazil. This study aimed to translate, adapt and examine the psychometric properties, internal consistency and construct validity of The Security in the Interparental Subsystem Scale (SIS) in a sample of 345 adolescents aged 14 to 18 years (M = 16.06 years, SD = 1.22). The results, obtained by Structural Equation Modeling, showed a six-factor version, namely: emotional reactivity, behavioral dysregulation, avoidance, involvement, destructive representations of the family, and representations of conflict overflow. The models showed good adjustment with invariance between the analyzed groups. The reliability of the scale showed adequate values. The tests performed suggest that the SIS presents satisfactory psychometric properties in the population of adolescents in the sample, therefore, a reliable measuring instrument for use in Brazil by clinicians and researchers.

Resumen la regulación emocional en los adolescentes es un aspecto poco observado, especialmente por los investigadores y los profesionales de la salud en Brasil. Este estudio tuvo como objetivo traducir, adaptar y examinar las propiedades psicométricas, la consistencia interna y la validez de constructo de La Escala de Seguridad en el Subsistema Interparental (SIS) en una muestra de 345 adolescentes de 14 a 18 años (M = 16.06 años, DT = 1.22). Los resultados, obtenidos mediante Modelización de Ecuaciones Estructurales, mostraron una versión de seis factores: reactividad emocional, desregulación conductual, evitación, implicación, representaciones destructivas de la familia, representaciones del desbordamiento del conflicto. Los modelos mostraron un buen ajuste con invarianza entre los grupos analizados. La confiabilidad de la escala mostró valores adecuados. Las pruebas realizadas sugieren que el SIS tiene propiedades psicométricas satisfactorias en la muestra de adolescentes, por lo tanto, un instrumento de medición fiable para su uso en Brasil por clínicos e investigadores.

Resumo a regulação emocional em adolescentes é um aspecto pouco observado, sobretudo, por pesquisadores e profissionais de saúde no Brasil. Este estudo teve como objetivo traduzir, adaptar e examinar as propriedades psicométricas, consistência interna e validade de constructo da The Security in the Interparental Subsystem Scale (SIS) em uma amostra de 345 adolescentes com idades entre com idades entre 14 e 18 anos (M = 16,06 anos, DP = 1,22). Os resultados, obtidos pela Modelagem de Equações Estruturais, evidenciaram uma versão de seis fatores, são eles: reatividade emocional, desregulação comportamental, evasão, envolvimento, representações destrutivas da família, representações do transbordamento do conflito. Os modelos apresentaram bom ajuste com invariância entre os grupos analisados. A confiabilidade da escala apresentou valores adequados. Os testes realizados sugerem que a SIS apresenta propriedades psicométricas satisfatórias na população de adolescentes da amostra, portanto, um instrumento de medida confiável para uso no Brasil por clínicos e pesquisadores.

Abstract Introduction: Lifestyle changes are the mainstay treatment of nonalcoholic fatty liver disease (NAFLD). We aimed to assess the magnitude of weight loss in a group of NAFLD patients followed on a combined lifestyle intervention by a multidisciplinary team. Methods: Patients were assessed before and after a 12-month dietary intervention (Mediterranean diet aiming at weight loss). Patients who received a structured dietary plan along with general lifestyle recommendations were designated as the multidisciplinary treatment (MdT) group. Patients who declined follow-up still received general lifestyle recommendations and were designated as the conventional treatment group, being used as a control group. Results: From the 77 patients with documented NAFLD, 31.2% of patients were overweight and 55.8% obese; 66 patients constituted the MdT group and 11 the conventional treatment group. After 3 months, 89% of patients lost weight; at 6 months, 75.4% maintained the weight lost. At 12 months, 65% of patients still decreased their weight, with 92.2% of patients in the MdT group still maintaining a lower weight than baseline versus just 50% in the conventional group (p = 0.008). Only patients in the MdT group presented a weight loss higher than 10% (9.6%; n = 6). At 12 months patients in the MdT group presented an average reduction of 4.2 kg versus a reduction of just 0.6 kg in the conventional treatment group (p = 0.016). The MdT group, but not the conventional group, presented significant differences in liver enzymes at 12 months compared to baseline. Conclusion: Adherence to a multidisciplinary approach, compared to management solely by a hepatologist, in NAFLD patients, is effective with greater weight loss after a 12-month follow-up and a lower rate of weight gain recurrence.

Resumo Introdução: Mudanças no estilo de vida são a base do tratamento do fígado gordo não-alcoólico (FGNA). O nosso objetivo foi avaliar a magnitude da perda de peso num grupo de doentes com FGNA sujeitos a intervenção nutricional e acompanhados por uma equipa multidisciplinar. Métodos: Os doentes foram avaliados antes e após uma intervenção nutricional de 12 meses (dieta mediterrânica com objetivo de perda ponderal). Os doentes que recusaram follow-up multidisciplinar, receberam recomendações gerais de estilo de vida e foram designados como grupo de tratamento convencional e usados como comparação com o grupo de tratamento multidisciplinar (MD), que em adição às recomendações gerais, recebeu plano nutricional personalizado. Resultados: Dos 77 pacientes com FGNA documentado, 31.2% dos pacientes estavam em pré-obesidade e 55.8% eram obesos; 66 pacientes constituíram o grupo MD e 11 o grupo de tratamento convencional. Após 3 meses, 89% dos pacientes perderam peso, aos 6 meses, 75.4% mantiveram a perda de peso. Aos 12 meses, 65% dos pacientes ainda diminuíram o seu peso, com 92.2% dos pacientes no grupo MD mantendo um peso inferior ao inicial vs. 50% no grupo convencional (p = 0.008). Apenas os pacientes do grupo MD, conseguiram uma perda de peso superior a 10% (9.6%; n = 6). Aos 12 meses, os pacientes do grupo MD apresentaram redução média de 4.2 kg vs. redução de 0.6 kg no grupo de tratamento convencional (p = 0.016). O grupo MD apresentou diferenças significativas nas enzimas hepáticas aos 12 meses em comparação com valores iniciais. Conclusão: A abordagem multidisciplinar em pacientes com FGNA é efetiva, com maior perda de peso durante o acompanhamento de 12 meses e maior taxa de perda de peso mantida, em comparação com acompanhamento exclusivamente pelo hepatologista.

Abstract Celiac disease (CD) is a systemic disease triggered by gluten ingestion in genetically predisposed individuals. It manifests primarily as an autoimmune enteropathy associated with specific circulating autoantibodies and a human leukocyte antigen haplotype (HLA-DQ2 or HLA-DQ8). It afflicts roughly 1% of the population, though the majority of patients remain undiagnosed. Diarrhea and malabsorption are classic manifestations of CD; however, both children and adults can be paucisymptomatic and present extraintestinal manifestations such as anemia, osteoporosis, and abnormal liver tests. CD screening is not recommended for the general population, and it should be focused on high-risk groups. CD diagnosis is challenging and relies on serological tests, duodenal histology, and genetic testing. Particularly difficult presentations to manage are seronegative patients, seropositive patients without villus atrophy, and patients who have started a gluten-free diet before the diagnostic workup. The only proven treatment is a lifelong gluten-free diet. We present an in-depth review on the physiopathology and management of CD, with a particular emphasis on diagnostic challenges.

Resumo A doença celíaca (DC) é uma doença sistémica desencadeada pela exposição ao glúten em doentes geneticamente susceptíveis. Manifesta-se maioritariamente por uma enteropatia auto-imune associada a auto-anticorpos e aos haplotipos HLA-DQ2 ou HLA-DQ8. A DC afecta aproximadamente 1% da população mundial admitindo-se, no entanto, que a maioria dos doentes não esteja diagnosticada. As manifestações clássicas de DC são a diarreia e sintomas de malabsorção, no entanto tanto crianças como adultos podem ser pauci-sintomáticos ou apresentar manifestações extra-intestinais incluindo anemia, osteoporose ou alteração das provas hepáticas. O rastreio de base populacional não está recomendado, devendo o foco ser nos grupos de risco para DC. O diagnóstico de DC é um desafio e assenta em três pilares: testes serológicos, histologia duodenal e testes genéticos. Apresentações particularmente difíceis de manejar são os doentes sero-negativos, doentes sero-positivos sem atrofia vilositária e doentes que iniciam dieta sem glúten antes da marcha diagnóstica. O único tratamento com eficácia comprovada é a dieta sem glúten. Apresentamos uma revisão aprofundada da fisiopatologia e manejo da DC, com particular ênfase nos desafios diagnósticos.

Abstract This study characterized the physical, chemical, macro- and micromorphological soil properties from three successive marine terrace levels from Harmony Point (Nelson Island, Maritime Antarctica) in order to understand the pedological signatures of Quaternary coastal landscape evolution of Maritime Antarctica. Soils were sampled on the Late Holocene beach (current beach) and Mid Holocene marine terraces higher up, at 3, 8, and 12 m a.s.l. At the lower levels, the predominant soils were Gelorthents, whereas Haplogelepts dominate the higher terraces. Soil properties are mostly influenced by parent material and faunal activity, in which cryoclastic (thermal weathering) and phosphatization are the main soil-forming processes. Soils from the upper levels are more developed, deeper with reddish colors, granular structures and incipient formation B horizon. These horizonation features highlight that soils vary according with age of glacier-isostatic terrace uplift, representing a Quaternary soil chronosequence. All marine terrace levels are Ornithogenic soils, at varying degrees. However, the presence of old bird nesting sites for long periods led to formation of phosphatic horizons, stable Fe-phosphate minerals and abundant vegetation in the highest terraces of this part of Maritime Antarctica.

Abstract The majority of ornithogenic soils studied in Antarctica focus on the influence of penguins, wherever little reports evaluated the influence of flying birds on soil genesis. This study aimed to characterize the morphologic, chemic, physic, mineralogic, and micromorphologic ornithogenic soil pockets influenced by flying birds in Snow Island, Maritime Antarctica. Fifteen soil pockets were selected, described, sampled and analyzed, these sites constitute the main areas with intense long-term terrestrial biological activity in Snow Island. In order to investigate the impact of phosphatization, we compared the soil pockets with the surrounding soils and soils affected by penguins. Zone of phosphatization have a high concentration of P, K, and Ca. The XRD patterns for the clay fraction of ornithogenic soils show that phosphate minerals are the main crystalline phases (leucophosphite, minyulite, fluorapatite, and apatite). We show that even under typical periglacial conditions, sites influenced by flying birds present active chemical weathering processes. The phosphatization release exchangeable bases and accelerate mineralogical and micromorphological transformations in soils. Under the current global warming trend and expected sea-level rise, the ornithogenic environments are susceptible to accelerated erosion rates and a great part of these hotspots may be lost for the open sea.

Abstract Faced with the increase of type 2 Diabetes mellitus (DM2) and the failure in treatment, questions have been raised about the clinical situation of these patients. The present study analyzes the prevalence of hypertension and obesity in DM2 patients. Data were collected through interviews and anamnesis of 16 participants. After the meetings, in which capillary glycemia and blood pressure were measured, the participants received guidance about glycemic monitoring, blood pressure control and changes in lifestyle. Approximately 75% of the participants were women with average age of 65 years, 87.5% were sedentary, 18.75% smoked and/or used alcoholic beverages and none performed regular blood glucose monitoring. The initial blood glucose average was 148 mg/ dL and finally decreased to 133 mg/dL. There was no significant difference in blood pressure levels. Regarding the body mass index, 89.4% of the patients were above normal standards and 100% had altered waist circumference values. There is a need for studies like this in order to promote educational practices for health and disease control, highlighting the importance of multidisciplinary teams and the pharmaceutical professional, since non-adherence to blood glucose monitoring, also associated with hypertension and obesity, can interfere with the individual’s clinical condition.

Abstract Microgrids (MGs) have increasingly attracted the attention of researchers, government officials, and electricity companies for the values and services they can add to the grid. They can operate independently as a single controllable unit in a coordinated way while connected or islanded, which make them suitable to integrate the growing amount of distributed energy resources (DERs) into the distribution network (DN). An active distribution network with high penetration of DERs could be redefined into a collection of microgrids in different layers, pooling their resources together to enhance the grid’s performance in the sense of electricity as a service. However, enabling a microgrid-based power system infrastructure poses challenges concerning operation and control. In this paper, a comprehensive overview of research topics regarding microgrid operation are shown in a hierarchical or stratified manner, looking for a holistic vision of a microgrid-based distribution system. First, multi-objective optimization within one microgrid is formulated aiming to minimize costs and maximize battery life is presented. Second, the interaction among MGs, DERs and the DN was modeled using the OPF technique to represent the operation of the grid as a whole. Following, a methodology for collaborative optimization of multiple MGs operating together is presented and at last a theoretical framework for MG operation through decentralized energy markets is discussed. As a result, this paper aims to contribute to a broad vision of the distribution system based on microgrid operation in all its levels.

Devido à pandemia da COVID-19, as Instituições de Ensino Superior (IES) necessitaram elaborar estratégias para manter as atividades de ensino e garantir que os alunos permaneçam com acesso à educação durante o isolamento social. Nesse contexto, a incorporação de metodologias ativas e o uso de recursos como jogos educativos se tornam ferramentas importantes para permitir aos discentes maior socialização, desenvolvimento da criatividade e a iniciativa para a resolução de problemas. O presente trabalho teve por objetivo elaborar um jogo didático baseado no Jogo Perfil, com o propósito de auxiliar na fixação de conceitos importantes na disciplina de Biofísica. A proposta do jogo foi estimular a motivação dos alunos, auxiliar na fixação de conceitos relacionados ao tema de estudo e promover uma maior socialização dos estudantes. No total, 39 alunos participantes foram questionados ao final do jogo sobre a sua percepção e aprendizado, e relataram que a estratégia contribuiu para sua motivação e melhor desempenho na disciplina. Estratégias como a elaboração de jogos didáticos e metodologias ativas são importantes para que assuntos mais complexos, como o ensino da Biofísica, se tornem mais prazerosos e tragam maior participação efetiva dos estudantes no processo de aprendizagem.

Due to the COVID-19 pandemic, Higher Education Institutions (HEIs) needed to develop strategies to maintain teaching activities and ensure that students remain with access to education during social isolation. In this context, the incorporation of active methodologies and the use of resources such as educational games become an important tool to allow students greater socialization, development of creativity and the initiative to solve problems. The present work had for objective to elaborate a didactic game based on the Profile Game, with the purpose of helping in the fixation of important concepts in the discipline of Biophysics. The purpose of the game was to stimulate students’ motivation, assist in fixing concepts related to the topic of study and promote greater socialization of students. In total, 39 participating students were asked at the end of the game about their perception and learning and reported that the strategy contributed to their motivation and better performance in the discipline. Strategies such as the development of didactic games and active methodologies are important so that more complex subjects, such as the teaching of Biophysics, become more pleasurable and bring greater effective participation of students in the learning process.

A colangite esclerosante secundária em doentes críticos (CEP-DC) é uma doença colestática, identificada recentemente, que ocorre em doentes sem antecedentes de patologia hepato-biliar, após internamento em unidade de cuidados intensivos (UCI) por diferentes indicações, incluindo: cirurgia cárdio-torácica, infeção, trauma e queimaduras. É uma entidade rara, com uma incidência estimada de um em cada 2,000 doentes em UCI. Ainda assim, trata-se de uma doença com um muito mau prognóstico, sendo que até metade dos doentes morre durante o internamento na UCI, e apresenta uma rápida progressão para cirrose em semanas a meses. A CEP-DC deve ser considerada no diagnóstico diferencial de colestase em UCI, particularmente se a colestase persistir após a recuperação do evento potencialmente fatal. O diagnóstico é estabelecido através de colangiopancreatografia por ressonância magnética ou colangiopancreatografia retrógrada endoscópica, que revelam estenoses e dilatações difusas dos canais biliares intra-hepáticos e cilindros biliares. Não está disponível uma terapêutica capaz de atrasar a rápida progressão da doença e a referenciação para transplantação hepática deve ser considerada logo após o diagnóstico. Para melhorar o mau prognóstico atual, é essencial um maior reconhecimento e diagnóstico precoce.

Secondary sclerosing cholangitis in critically ill patients (SSCCIP) is a recently identified cholestatic liver disease occurring in patients without prior history of hepatobiliary disease, after receiving treatment in the intensive care unit (ICU) in different settings, including cardiothoracic surgery, infection, trauma, and burns. It is a rare entity, being estimated to occur in 1/2,000 patients in an ICU; however, it is a dismal condition, with up to half of the patients dying during the ICU stay and with rapid progression to liver cirrhosis over weeks to months. SSC-CIP should be considered in the differential diagnosis of cholestasis in the ICU, particularly when cholestasis persists after recovery from the critical event. Diagnosis is established with magnetic resonance cholangiopancreatography or endoscopic retrograde cholangiopancreatography showing dilations and stenoses of the intrahepatic bile ducts as well as biliary casts. No available treatment has been shown to slow the rapid progression of the disease, and liver transplant referral should be considered early after the diagnosis of SSC-CIP. Increased awareness and timely diagnosis are crucial in order to improve the current appalling outcome.

Resumo Dificuldades no exercício da coparentalidade reverberam em problemas externalizantes em adolescentes. Entretanto, há escassez no entendimento sobre mecanismos que medeiam essa relação. A regulação emocional apresenta-se como possível ligação entre esses construtos. O objetivo deste estudo foi testar um modelo estrutural no qual a desregulação emocional é mediadora entre coparentalidade e problemas externalizantes em adolescentes. Trata-se de estudo com delineamento quantitativo, transversal, explicativo. Contou com uma amostra de 229 adolescentes entre 11 a 18 anos, residentes no interior do Rio Grande do Sul. Foi utilizada modelagem de equações estruturais para testar a validade empírica do modelo teórico proposto. Os resultados forneceram evidências para o avanço do estudo das relações familiares e mecanismos explicativos no desenvolvimento de problemas externalizantes. Alguns domínios de desregulação emocional são mediadores da associação entre dimensões negativas de coparentalidade e problemas externalizantes. As relações diretas e indiretas entre as variáveis do modelo são analisadas e discutidas.

Abstract Difficulties in coparenting performance reverberate in externalizing problems in adolescents. However, understanding on the mechanisms mediating this relationship is scarce. Emotion regulation is a possible link between these constructs. This study aims to test a structural model in which emotional dysregulation mediates coparenting and externalizing problems in adolescents. This is a quantitative, cross-sectional, and explanatory study. The sample consisted of 229 adolescents aged between 11 and 18, living in inland cities of Rio Grande do Sul. Structural equation modeling was used to test the empirical validity of the proposed theoretical model. Results provided evidence for the advance of the study on family relationships and explanatory mechanisms in the development of externalizing problems. Some domains of emotion deregulation mediate the association between coparenting negative dimensions and externalizing problems. Direct and indirect relationships between the model variables are analyzed and discussed.

Resumen Las dificultades en la coparentalidad reverberan en problemas de externalización en adolescentes. Sin embargo, existe una falta de comprensión sobre los mecanismos que median esta relación. La regulación emocional es un posible vínculo entre estos constructos. El objetivo de este estudio fue probar un modelo estructural en el que la desregulación emocional es mediadora entre la coparentalidad y los problemas de externalización en adolescentes. Este es un estudio cuantitativo, transversal y explicativo. Cuenta con una muestra de 229 adolescentes entre 11 y 18 años que viven en el interior de Rio Grande do Sul. Se utilizó el modelo de ecuaciones estructurales para probar la validez empírica del modelo teórico propuesto. Los resultados proporcionaron evidencia para el avance del estudio de las relaciones familiares y los mecanismos explicativos en el desarrollo de problemas de externalización. Algunos dominios de desregulación emocional median la asociación entre las dimensiones negativas de los problemas de coparentalidad y problemas de externalización. Se analizan y discuten las relaciones directas e indirectas entre las variables del modelo.

Resumo A compreensão do comportamento in vitro de explantes de flamboyant cultivados em meio de cultura suplementado com diferentes tipos e concentrações de citocininas pode auxiliar na otimização de sistemas de regeneração estabelecidos para essa espécie vegetal. Objetivou-se com o presente estudo avaliar o comportamento de explantes cotiledonares de flamboyant quando cultivados na presença de elevadas concentrações de 6-benziladenina (BA) ou cinetina (KIN). Segmentos cotiledonares obtidos de plântulas germinadas in vitro foram inoculados em meio de cultura Murashige e Skoog (MS), suplementado com diferentes concentrações (1, 2, 4, 8 mg L-1) de 6-benziladenina (BA) ou cinetina (KIN). No tratamento controle não foi adicionado reguladores de crescimento. Após 40 dias de cultivo, independente da concentração utilizada, os tratamentos suplementados com BA apresentaram maiores porcentagens de formação de calos e massa fresca, em comparação aos tratamentos suplementados com KIN. A formação de gemas adventícias foi observada principalmente nos tratamentos suplementados com BA. Análises histológicas evidenciaram que a formação de gemas adventícias ocorreu na periferia de calos formados a partir de células do mesofilo, nas regiões de seccionamento do explante. Os resultados obtidos fornecem novas informações para o estabelecimento de um sistema de micropropagação de flamboyant, uma importante espécie arbórea ornamental.

Abstract Understanding the in vitro performance of royal poinciana explants cultured in media supplemented with different types and concentrations of cytokinins may aid in the optimization of regeneration systems established for this woody species. In the present study we evaluate the in vitro performance of royal poinciana cotyledonary explants cultured in the presence of high concentrations of 6-benzyladenine (BA) and kinetin (KIN). Cotyledonary segments obtained from in vitro germinated seedlings were inoculated in Murashige and Skoog (MS) medium, supplemented with different concentrations (1, 2, 4, 8 mg L-1) of BA or KIN. In the control treatment, no plant growth regulators (PGRs) were added. After 40 days of culture, regardless of the concentration used, the treatments supplemented with BA presented higher calli percentage and fresh mass compared to treatments supplemented with KIN. Adventitious shoots were mainly observed in BA-treatments. Histological analysis showed that adventitious shoots formed at the periphery of callus formed from mesophyll cells in the regions of the explant sectioning. The results obtained provide new information for the establishment of a micropropagation system for royal poinciana, an important ornamental tree species.