Objetive: The aim of this study was to analyze possible horizontal transmission patterns of S. mutans among 6-7-yr-old schoolchildren from the same class, identifying genotypes and their diversity and relationship with caries disease status. Study Design: Caries indexes and saliva mutans streptococci and lactobacilli counts were recorded in 42 schoolchildren. Mutans streptococci colonies were identified by means of biochemical tests and all S. mutans strains were genotyped by arbitrarily primed polymerase chain reaction. A child was considered free of S. mutans when it could not be isolated in 3 samples at 1-week intervals. Results: S. mutans was isolated in 30 schoolchildren: 20 having one genotype and 10 two genotypes. Higher mutans streptococci and caries index values were found in those with two genotypes. Five genotypes were isolated in more than 1 schoolchild and one of these was isolated in 3 schoolchildren. Our results suggest that horizontal transmission may take place. Conclusion: Schoolchildren aged 6-7 yrs may be the source of mutual transmission of S. mutans. Key words:Streptococcus mutans, Horizontal transmission, AP-PCR, genotyping

No abstract

The growth curve interference (GCI) induced by different antibiotics was studied using reference strains of oral streptococci. This parameter may prove to be useful in preventing subacute endocarditis of odontological origin in high-risk patients. The growth curves using different concentrations of antibiotics and with an initial optical density (OD) of 0.05 ± 0.01 were observed until an OD of 0.9-1.0 was reached. The GCI was defined as the lowest concentration of antibiotic that modified the growth curve with respect to a control without antibiotic. The GCI values were then compared with the minimum inhibitory concentration (MIC) values. In all cases, interference in the growth curves was at least one concentration lower than the MIC in a time ranging from 4-6 h.

RESUMENLa ivermectina es un fármaco antiparasitario muy utilizado en Medicina Veterinaria, dado su espectro de actividad que abarca tanto endo como ectoparásitos, elevada eficacia y amplio margen de seguridad. No obstante, su administración puede dar lugar a efectos tóxicos. La mayoría de ellos derivan de la sobredosificación del compuesto, aunque también se han descrito, a dosis terapéuticas, casos de susceptibilidad extrema a los efectos neurotóxicos del fármaco en determinadas razas o subpoblaciones de animales, así como reacciones anafilácticas por la destrucción masiva de parásitos.Palabras clave: ivermectina, toxicidad, efectos adversos. ABSTRACTThe antiparasitic drug Ivermectin is frequently used in veterinary medicine, due to its broad spectrum of activity (both against endo-and ectoparasites, high efficacy and wide margin of safety. However, its administration can give rise to toxic effects. Most of them come from the overdosage of the compound, although, at therapeutic doses, it also has been described an increased susceptibility to Ivermectin toxicosis in some breeds and subpopulations of animals, as well as severe anaphylactic reactions due to the sudden massive release of parasite toxins.

Resumo Enquadramento: na população estudantil do ensino superior, muitos comportamentos podem afetar o sucesso escolar. Objetivo: analisar a associação entre o consumo dos principais psicoativos e o sucesso escolar dos estudantes do ensino superior. Metodologia: estudo transversal, descritivo, quantitativo e analítico. Questionário online aplicado aos alunos do Instituto Politécnico de Bragança (IPB), Portugal, após o primeiro semestre letivo de 2020/2021. Amostra de 825 alunos estratificada por escola, com base numa população de 8875 alunos matriculados. Resultados: evidenciou-se relação estatisticamente significativa entre quem consome medicamentos psicoativos e/ou drogas recreativas com o menor rendimento escolar. Verificou-se que as práticas abusivas de binge drinking/smoking e a que a combinação com um terceiro psicoativo também estão associados a menor desempenho académico. Com a pandemia Covid-19 os estudantes percecionaram aumento de consumos dos principais psicoativos e diminuição do sucesso escolar. Conclusão: o consumo abusivo de psicoativos causa insucesso escolar e a pandemia COVID-19 agravou ambos problemas. Palavras-chave: psicoativos, sucesso escolar, ensino superior, covid-19 Abstract Background: Many behaviours can affect school achievement in the higher education student population. Objective: To analyse the association between the consumption of the main psychoactive substances and the school achievement of higher education students. Methodology: A cross-sectional, descriptive, quantitative, and analytical study. The questionnaire was applied to the students at the Polytechnic Institute of Bragança (IPB), Portugal, after the first semester of 2020/2021. The sample comprised 825 students, stratified by school, based on a population of 8,875 enrolled students. Results: A statistically significant relationship was found between those who consume psychoactive medicines and/or recreational drugs with the lowest school performance. Abusive binge drinking/smoking practices and the combination with a third psychoactive substance were also found to be associated with lower academic performance. With the COVID-19 pandemic, students perceived increased consumption of the main psychoactive substances and decreased school achievement. Conclusion: abusive consumption of psychoactive substances causes school failure, and the COVID-19 pandemic has further aggravated these problems. Keywords: psychoactive substances, school achievement, higher education, covid-19