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Mast cells, known as pro‐inflammatory effector cells, are immunocytes present in the meninges and may be involved in the pathophysiology of migraine. This study aims to evaluate the histomorphometric parameters of mast cells located in the convexity of the human intracranial dura mater. For this, samples of intracranial dura mater from eight human fresh cadavers were collected between 8‐ and 24‐h post‐mortem. The whole samples were fixed and, subsequently, two fragments of 1.5 cm² each were cut from four different areas of the dura mater convexity, containing a segment of the middle meningeal artery, totaling 64 fragments. After histological processing, the fragments were submitted to microtomy (5 and 10 µm), stained with toluidine blue (0.1%), or immunohistochemically labeled for tryptase, and analyzed using optical microscopy. The following histomorphometric parameters were evaluated: distance from mast cells to vessels, the density of mast cells, and percentage of mast cells with degranulation. Histomorphometric analyzes showed a higher density of mast cells in the vicinity of blood vessels (arterial and venous), with distances around 0–150 µm. A greater number of mast cells was detected near venous vessels in the periosteal layer (17.0 ± 10.1 cells/mm²) than in the meningeal layer (14.1 ± 7.0 cells/mm²) (p < 0.05). Mast cells from the region close to the superior sagittal sinus were found in greater quantity close to the venous vessels (16.7 ± 10.1 cells/mm²) than to the arterial vessels (11.2 ± 7.5 cells/mm²) (p < 0.05). In short, in the convexity of the human intracranial dura mater, mast cells are located close to blood vessels, with a greater number of cells next to the venous vessels of the periosteal layer and in the proximal region of the superior sagittal sinus. [ABSTRACT FROM AUTHOR]

Leishmaniasis is considered by the World Health Organization as one of the infectious parasitic diseases endemic of great relevance and a global public health problem. Pentavalent antimonials used for treatment of this disease are limited and new phytochemicals emerge as an alternative to existing treatments, due to the low toxicity and cost reduction. Usnic acid is uniquely found in lichens and is especially abundant in genera such as Alectoria, Cladonia, Evernia, Lecanora, Ramalina, and Usnea. Usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory, and analgesic activity. The aim of this study was to evaluate the antileishmanial activity of usnic acid on Leishmania infantum chagasi promastigotes and the occurrence of drug-induced ultrastructural damage in the parasite. Usnic acid was effective against the promastigote forms (IC50 = 18.30 ± 2.00 µg/mL). Structural and ultrastructural aspects of parasite were analyzed. Morphological alterations were observed as blebs in cell membrane and shapes given off, increasing the number of cytoplasmic vacuoles, and cellular and mitochondrial swelling, with loss of cell polarity. We concluded that the usnic acid presented antileishmanial activity against promastigote forms of Leishmania infantum chagasi and structural and ultrastructural analysis reinforces its cytotoxicity. Further, in vitro studies are warranted to further evaluate this potential. [ABSTRACT FROM AUTHOR]

Abstract: Colon adenocarcinoma is a disease expanding worldwide. Cancer of colon and rectum are among the top ten most insidious types in Brazil. In vitro and in vivo studies have demonstrated the efficacy of the hormone melatonin to prevent and reduce tumor growth. However, there are only few studies addressing the action of melatonin on Caco-2 cells. Thus, the cytotoxic effect of melatonin on the ultrastructure of Caco-2 cells was investigated. The MTT colorimetric method was used to assess the cytotoxicity. A total of 2×106 cells/mL were seeded in microplates and incubated at 50, 25, 12.5, 6.25, 3.125, 1.56, 0.78 and 0.0 (control) μg/mL of melatonin. For ultrastructural analysis concentrations with low, medium and high cytotoxicity plus the control were used for ultrastructural analysis. The concentrations 50, 1.56 and 0.78μg/mL of melatonin showed low, medium and high cytotoxicity, respectively. Ultrastructurally, the control tumor cells were shown to be preserved. Caco-2 cells showed morphological changes at 50μg/mL of melatonin, with numerous vacuoles, mitochondrial degeneration and reduced glycogen. However, Caco-2 cells also showed altered morphology in treatments at 1.56 and 0.78μg/mL of melatonin with characteristics of cells in degeneration by the presence of numerous vacuoles, absence of microvilli, mitochondrial degeneration and nuclear fragmentation. Thus, one can infer that concentrations of 1.56 and 0.78μg/mL of melatonin promote cytotoxicity in Caco-2 cells, which can probably be related to the generation of reactive oxygen species (ROS). [Copyright &y& Elsevier]

Leishmaniasis is considered by the World Health Organization as one of the infectious parasitic diseases endemic of great relevance and a global public health problem. Pentavalent antimonials used for treatment of this disease are limited and new phytochemicals emerge as an alternative to existing treatments, due to the low toxicity and cost reduction. Usnic acid is uniquely found in lichens and is especially abundant in genera such as Alectoria, Cladonia, Evernia, Lecanora, Ramalina, and Usnea. Usnic acid has been shown to exhibit antiviral, antiprotozoal, antiproliferative, anti-inflammatory, and analgesic activity. The aim of this study was to evaluate the antileishmanial activity of usnic acid on Leishmania infantum chagasi promastigotes and the occurrence of drug-induced ultrastructural damage in the parasite. Usnic acid was effective against the promastigote forms (IC50=18.30±2.00 µg/mL). Structural and ultrastructural aspects of parasite were analyzed. Morphological alterations were observed as blebs in cell membrane and shapes given off, increasing the number of cytoplasmic vacuoles, and cellular and mitochondrial swelling, with loss of cell polarity. We concluded that the usnic acid presented antileishmanial activity against promastigote forms of Leishmania infantum chagasi and structural and ultrastructural analysis reinforces its cytotoxicity. Further, in vitro studies are warranted to further evaluate this potential.