ABSTRACT
BACKGROUND: Almost all Tityus characterized toxins are from subgenera Atreus and Tityus, there are only a few data about toxins produced by Archaeotityus, an ancient group in Tityus genus. METHODS: Tityus (Archaeotityus) mattogrossensis crude venom was fractionated by high performance liquid chromatography, the major fractions were tested in a frog sciatic nerve single sucrose-gap technique. Two fractions (Tm1 and Tm2) were isolated, partially sequenced by MALDI-TOF/MS and electrophysiological assayed on HEK293 Nav 1.3, HEK293 Nav 1.6, DUM and DRG cells. RESULTS: The sucrose-gap technique showed neurotoxicity in four fractions. One fraction caused a delay of action potential repolarization and other three caused a reduction in amplitude. An electrophysiological assay showed that Tm1 is active on HEK293 Nav 1.3, HEK293 Nav 1.6, DUM and DRG cells, and Tm2 on HEK293 Nav 1.3 and DRG cells, but not in HEK293 Nav 1.6. In addition, Tm1 and Tm2 did promote a shift to more negative potentials strongly suggesting that both are α-NaScTx. CONCLUSION: Although Tityus (Archaeotityus) mattogrossensis is considered an ancient group in Tityus genus, the primary structure of Tm1 and Tm2 is more related to Tityus subgenus. The patch clamp electrophysiological tests suggest that Tm1 and Tm2 are NaScTx, and also promoted no shift to more negative potentials, strongly suggesting that both are α-NaScTx. This paper aimed to explore and characterize for the first time toxins from the ancient scorpion Tityus (Archaeotityus) mattogrossensis.
ABSTRACT
In Brazil, governmental and non-governmental organisations develop practice guidelines (PGs) in order to optimise patient care. Although important improvements have been made over the past years, many of these documents still lack transparency and methodological rigour. In order to conduct a critical analysis and define future steps in PG development in Brazil, we carried out a structured assessment of strengths, weaknesses, opportunities and threats (SWOT analysis) for the development of a national guideline programme. Participants consisted of academia, methodologists, medical societies and healthcare system representatives. In summary, the PG development process has improved in Brazil and current investments in methodological research and capacity-building are ongoing. Despite the centralised processes for public PGs, standardised procedures for their development are not well established and human resources are insufficient in number and capacity to develop the amount of trustworthy documents needed. Brazil's capacity could be strengthened and initial efforts have been made such as the adoption of standards proposed by world-renowned institutions in PG development and enhancement of the involvement of key stakeholders. Further steps involve the alignment between health technology assessment and PG processes for synergy and the development of a national network to promote the interaction between groups involved in the development of PGs. The lessons learned from this paper could be used to foster debate on guideline development, especially for countries facing similar threats on this topic.
Subject(s)
Practice Guidelines as Topic , Program Development , Brazil , Capacity Building , Evidence-Based MedicineABSTRACT
This study evaluated the effects of [d-Leu¹]Microcystin-LR variant by the exposure of Lithobates catesbeianus tadpole to unialgal culture Microcystis aeruginosa NPLJ-4 strain. The Tadpole was placed in aquariums and exposed to Microcystis aeruginosa culture or disrupted cells. For 16 days, 5 individuals were removed every 2 days, and tissue samples of liver, skeletal muscle, and intestinal tract were collected for histopathology and bioaccumulation analyses. After exposure, those surviving tadpoles were placed in clean water for 15 days to evaluate their recovery. A control without algae and toxins was maintained in the same conditions and exhibited normal histology and no tissue damage. In exposed tadpoles, samples were characterized by serious damages that similarly affected the different organs, such as loss of adhesion between cells, nucleus fragmentation, necrosis, and hemorrhage. Samples showed signs of recovery but severe damages were still observed. Neither HPLC-PDA nor mass spectrometry analysis showed any evidence of free Microcystins bioaccumulation.
