Guava extract (Psidium guajava) alters the labelling of blood constituents with technetium-99m.

Psidium guajava (guava) leaf is a phytotherapic used in folk medicine to treat gastrointestinal and respiratory disturbances and is used as anti-inflammatory medicine. In nuclear medicine, blood constituents (BC) are labelled with technetium-99m ((99m)Tc) and used to image procedures. However, data have demonstrated that synthetic or natural drugs could modify the labelling of BC with (99m)Tc. The aim of this work was to evaluate the effects of aqueous extract of guava leaves on the labelling of BC with (99m)Tc. Blood samples of Wistar rats were incubated with different concentrations of guava extract and labelled with (99m)Tc after the percentage of incorporated radioactivity (%ATI) in BC was determined. The results suggest that aqueous guava extract could present antioxidant action and/or alters the membrane structures involved in ion transport into cells, thus decreasing the radiolabelling of BC with (99m)Tc. The data showed significant (P<0.05) alteration of ATI in BC from blood incubated with guava extract.

Ultra-som na avaliaçäo da doença nodular da tireóide: experiência de um grupo multidisciplinar / Ultrasonography in the evaluation of thyroid nodular disease: experience of a multidisciplinary group

O objetivo do trabalho foi correlacionar as características ecográficas dos nódulos tireóideos aos achados citológicos, para determinar a importância da ultra-sonografia na doença nodular da tireóide. Foram realizadas punçöes aspirativas por agulha fina orientadas por ultra-som, após avaliaçäo e classificaçäo ecográfica de 436 nódulos. Obteve-se celularidade adequada para análise em 401 nódulos (92 por cento), procedendo-se à correlaçäo ecográfico/citológica. A classificaçäo utilizada permitiu distribuir as características ecográficas de acordo com o risco de malignidade, identificando nódulos Grau III císticos com foco sólido (citologia positiva em 23,8 por cento) e sólidos hipoecóicos (40 por cento) como suspeitos e os Grau IV (95,2 por cento) como altamente suspeitos. Os nódulos Grau II sólidos iso e hiperecóicos (5 por cento) e mistos (1 ,9 por cento), em acordo com a literatura, foram considerados provavelmente benignos. O ultra-som forneceu auxílio importante à avaliaçäo clínica e determinaçäo da conduta a ser tomada, devendo fazer parte dos protocolos para avaliaçäo inicial e acompanhamento da doença nodular da tireóide.

Citotoxic effects of stannous salts and the action of Mytenus ilicifolia, Bacchris genistelloides and Cymbopogon citratus aqueous extracts

In nuclear medicine, stannous, as stannous chloride (SnCl2) and stannous fluoride (SnF2), are used as reducing agents to obtain radiopharmaceuticals labeled with technetium-99m. In the literature, the SnCl2 action was studied and it seems to be mediated through free radicals (FR) production in a Fenton-like reaction. In this work it was evaluated: (i) the in vitro SnF2 effects in different concentrations using pBCKS plasmid deoxyribonucleid acid (DNA); (ii) the SnF, effects in different Escherichia coli (E.coli) cultures, proficient or deficient in DNA repair genes, treated simultaneously with FR scavengers; and (iii) the biological effects of Maytenus ilicifolia, Baccharis genistelloides and Cymbopogon citratus aqueous extracts on the SnCL2 action in E.coli culture. The SnF2 treatment induced plasmidd DNA damages (single and double DNA strand breaks), in a dose-dependent manner. Citotoxicity mediated by SNf2 was observed and the simultaneous tratment with FR scavengers has increased the cell survival, suggesting the participation of FR on the SnF2-deleterious effects. The vegetal extrracts prottected the E.coli cells agains the SnCl2 effects. The components of the extracts could be interacting with SnCl2 blocking its participation in the FR formation.