RESUMO
A 46-year-old male experienced progressive neurocognitive decline, weight loss, intermittent headaches, and weakness over 6 months. Magnetic resonance imaging of the brain revealed hydrocephalus and the spinal cord imaging showed diffuse leptomeningeal enhancement with prominent nerve root involvement. Intradural biopsy of lumbar arachnoid tissue found mixed inflammatory infiltrate consisting predominantly of histiocytes, S100 and CD68 positivity, and lymphocytophagocytosis (emperipolesis) consistent with extranodal Rosai-Dorfman disease. Rosai-Dorfman disease, a non-Langerhans cell histocytic disorder, can mimic the appearance of neurosarcoidosis and leptomeningeal carcinomatosis and should remain on the differential of a patient presenting with diffuse leptomeningeal enhancement, a common occurrence on a neurohospitalist service.
RESUMO
Seven analogs of the natural, α-helix peptides IsCT1 and IsCT2-found in the venom of scorpion Opithancatus Madagascariensis-have been synthesized and tested to compare their antibacterial and hemolytic activity against natural peptides. In general, results show that increasing hydrophobicity by substituting positions 5 and 9 of the sequences with alanine, valine, and leucine, enhances antibacterial activity. However, this also increases hemolytic activity. The analog with an increased net positive charge from +1 to +3 produces moderate bacterial growth inhibition but also has high hemolytic activity. On the other hand, the analog with a negative net charge (-1) has low antibacterial properties but also no cytotoxicity under the tested conditions, a similar result was found for five of the seven studied analogs.
