Central nervous system metastasis from osteosarcoma: Case report and literature review.

Osteosarcoma is the most common primary malignancy of bone in children and young adults, the highest incidence peak is during adolescence and doesn't have any gender predominance. The main site of metastasis are the lungs and extrapulmonary cases are occasional. The incidence of metastasis in the Central Nervous System (CNS) is 2-6.5%, increase to 10-15% in patients with pulmonary metastases. Therefore, metastatic disease of the CNS is rare and the information on such patients is limited. Here, we describe a case of a 20-year old patient diagnosed with osteosarcoma in the left distal femur stage IIB, he developed pulmonary disease, during palliative chemotherapy experienced relapse to the brain classified as recursive partitioning analysis (RPA) class II, and was treated with external radiotherapy (30 Gy in 10 fractions) and later he had a poor evolution and died.

In silico molecular docking analysis of three molecules isolated from Litsea guatemalensis Mez on anti-inflammatory receptors.

BACKGROUND: The Litsea genus has four native species from Mesoamerica. Litsea guatemalensis Mez. is a native tree, traditionally used as a condiment and herbal medicine in the region. It has demonstrated antimicrobial, aromatic, anti-inflammatory and antioxidant activity. Bioactive fractionation attributed the anti-inflammatory and anti-hyperalgesic activities to pinocembrin, scopoletin, and 5,7,3´4´-tetrahydroxy-isoflavone. In silico analysis, these molecules were analyzed on receptors involved in the anti-inflammatory process to determine which pathways they interact. OBJECTIVE: To analyze and evaluate 5,7,3',4'-tetrahydroxyisoflavone, pinocembrin, and scopoletin using the in silico analysis against selected receptors involved in the inflammatory pathway. METHOD: Known receptors involved in the anti-inflammatory process found as protein-ligand complex in the Protein Data Bank (PDB) were used as references for each receptor and compared with the molecules of interest. The GOLD-ChemScore function, provided by the software, was used to rank the complexes and visually inspect the overlap between the reference ligand and the poses of the studied metabolites. RESULTS: 53 proteins were evaluated, each one in five conformations minimized by molecular dynamics. The scores obtained for dihydroorotate dehydrogenase were greater than 80 for the three molecules of interest, scores for cyclooxygenase 1 and glucocorticoid receptor were greater than 50, and identified residues with interaction in binding sites overlap with the reference ligands in these receptors. CONCLUSION: The three molecules involved in the anti-inflammatory process of L. guatemalensis show in silico high affinity to the enzyme dihydroorotate dehydrogenase, glucocorticoid receptors and cyclooxygenase-1.

Prevalence of burnout in medical students in Guatemala: Before and during Covid-19 pandemic comparison.

Burnout is a syndrome consisting of physical, emotional, and mental exhaustion along with depersonalization and poor sense of personal accomplishment. Often related to work conditions. Several recent studies from around the world have shown high rates of burnout among medical students in different countries. In Guatemala City, we decided to assess levels of burnout in 2017 and then again in December 2020. In the first wave from one private medical school, we had a total of 159 respondents (response rate of 56.7%) and 132 (48.5%) in the second wave. Not surprisingly rates of burnout were higher during the pandemic even though response rate is lower. Surprisingly we found that rates of depersonalization had not increased, and levels of personal accomplishment had. These findings present a mixed picture of levels of burnout in Guatemala City. Further qualitative research is indicated to explore cultural differences in order to set up appropriate and suitable intervention strategies.

Inhibition of enzymatic activities of Bothrops asper snake venom and docking analysis of compounds from plants used in Central America to treat snakebite envenoming.

ETHNOPHARMACOLOGICAL RELEVANCE: Snakebite envenoming is a public health problem of high impact in Central America. Bothrops asper, known as barba amarilla, terciopelo, and equis, is the snake species responsible for most snakebites in Central America. In this region, there is a long-standing tradition on the use of plants in the management of snakebites, especially in indigenous communities. Ethnomedical use of Eryngium foetidum L., Neurolaena lobata (L.) Cass. and Pimenta dioica (L.) Merr. to treat snakebite envenoming has been reported in Belice, Guatemala, Nicaragua, and Costa Rica. Extracts of the leaves of these plants have shown anti-venom activities in in vitro assays in previous studies. AIM OF THE STUDY: To assess the ability of organic fractions from these three plants to inhibit enzymatic activities associated with toxicity of the venom of B. asper, and to study, by docking analysis, the interaction of metalloproteinase and phospholipases A2 (PLA2) from B. asper venom with secondary metabolites previously described in these plants. MATERIALS AND METHODS: Organic fractions were obtained from these three plant species and their ability to neutralize proteolytic, PLA2 and in vitro coagulant activities of B. asper venom was assessed. A phytochemical analysis was carried out in these fractions. The interaction of secondary metabolites previously described in these plants with three toxins from B. asper venom (a metalloproteinase, a PLA2 and a PLA2 homologue) was investigated by docking analysis. RESULTS: The inhibitory activity of plants was mainly concentrated in their polar fractions. Acetonic fraction from P. dioica was the most active against PLA2 activity, while the acetonic fraction of E. foetidum completely inhibited the proteolytic activity of the venom. Coagulant activity was partially inhibited only by the acetone and ethyl acetate fractions of P. dioica. Phytochemical analysis of the most bioactive fractions identified flavonoids, saponins, essential oils, coumarins, alkaloids, tannins and sesquiterpene lactones. Docking analysis revealed high affinity interactions of several secondary metabolites of these plants with residues in the vicinity of the catalytic site of these enzymes and, in the case of PLA2 homologue myotoxin II, in the hydrophobic channel. CONCLUSIONS: Various fractions from these plants have inhibitory activity against enzymatic actions of B. asper venom which are directly associated with toxicological effects. Docking analysis showed structural evidence of the interaction of secondary metabolites with three toxins. These observations provide support to the potential of these plants to inhibit relevant toxic components of this snake venom.