Paradoxical Radiosensitizing Effect of Carnosic Acid on B16F10 Metastatic Melanoma Cells: A New Treatment Strategy.

Carnosic acid (CA) is a phenolic diterpene characterized by its high antioxidant activity; it is used in industrial, cosmetic, and nutritional applications. We evaluated the radioprotective capacity of CA on cells directly exposed to X-rays and non-irradiated cells that received signals from X-ray treated cells (radiation induced bystander effect, RIBE). The genoprotective capacity was studied by in vivo and in vitro micronucleus assays. Radioprotective capacity was evaluated by clonogenic cell survival, MTT, apoptosis and intracellular glutathione assays comparing radiosensitive cells (human prostate epithelium, PNT2) with radioresistant cells (murine metastatic melanoma, B16F10). CA was found to exhibit a genoprotective capacity in cells exposed to radiation (p < 0.001) and in RIBE (p < 0.01). In PNT2 cells, considered as normal cells in our study, CA achieved 97% cell survival after exposure to 20 Gy of X-rays, eliminating 67% of radiation-induced cell death (p < 0.001), decreasing apoptosis (p < 0.001), and increasing the GSH/GSSH ratio (p < 0.01). However, the administration of CA to B16F10 cells decreased cell survival by 32%, increased cell death by 200% (p < 0.001) compared to irradiated cells, and increased cell death by 100% (p < 0.001) in RIBE bystander cells (p < 0.01). Furthermore, it increased apoptosis (p < 0.001) and decreased the GSH/GSSG ratio (p < 0.01), expressing a paradoxical radiosensitizing effect in these cells. Knowing the potential mechanisms of action of substances such as CA could help to create new applications that would protect healthy cells and exclusively damage neoplastic cells, thus presenting a new desirable strategy for cancer patients in need of radiotherapy.

Absceso mastoideo como presentación de colesteatoma congénito en preescolar ¿cuál es el origen? / Mastoid abscess as congenital cholesteatoma presentation in a child what is the origin?

Resumen El colesteatoma congénito es una entidad que puede manifestarse con una amplia variedad de síntomas o ser silente durante largo tiempo y constituir un hallazgo incidental. Una vez diagnosticada es importante valorar su extensión y el compromiso de estructuras adyacentes, para lograr una adecuada planificación quirúrgica, eliminando la enfermedad y manteniendo la mejor funcionalidad posible. Se presenta un caso de colesteatoma congénito infantil.

Abstract Congenital cholesteatoma is an entity that can manifest with a wide variety of symptoms or be silent for a long time and constitute an incidental finding. Once diagnosed, it is important to assess the extension to apply the most efficient treatment, eliminating the disease and providing functionality if possible. A case of congenital cholesteatoma in a child is presented.

Incidence of smell and taste disorders and associated factors in patients with mild to moderate COVID-19.

<b>Objectives:</b> To determine the incidence of smell and taste disorders in our health department and to analyse the factors that could be associated with these symptoms in patients with COVID-19. <br><b>Methods:</b> We conducted an observational descriptive study of all patients with COVID-19 in our health area diagnosed between 2020/03/10 and 2020/04/14. Factors related to smell and taste disorders were analysed. <br><b>Results:</b> A total of 126 patients, 63 women and 63 men, aged 16-80 years, were included. As many as 69 patients (62.7%) presented hyposmia, and 58 (46%) of them had anosmia. A total of 75 patients (59.5%) presented hypogeusia, and 57 (45.2%) of them had ageusia. The risk factors that were most commonly associated with these disorders were the female sex (adjusted odds ratio, aOR 2.43 for smell disorders and 2.44 for taste disorders), allergic rhinitis (aOR 3.34 for smell disorders) and a younger age. A protective factor was arterial hypertension (aOR 0.51 for smell disorders and 0.35 for taste disorders). A history of tonsillectomy was the risk factor for taste disorder (aOR 5.23). <br><b>Conclusion:</b> Our results indicate that these sensory disorders occurred more frequently in female patients and in young patients with mild to moderate COVID-19 infection who progressed with mild nasal congestion, posterior rhinorrhoea and without anterior rhinorrhoea. The recovery of taste occurred before the recovery of smell.

Antioxidant activity of Plantago bellardii All.

The aim of this study was to evaluate the in vitro antioxidant activity of the methanol extract of Plantago bellardii All. aerial parts. This was assessed by two different tests, scavenging of 1,1-diphenyl-2-picrylhydrazil (DPPH) radical, and inhibition of lipid peroxidation on liposomes prepared from bovine brain extract. In both tests the extract showed a potent antioxidant effect. The characterization of the major compounds in the extract as rutin, geniposide and verbascoside was performed by isolation and HPLC comparison with authentic samples. They were quantified by HPLC for the flavonoids and colorimetry for iridoids. The compounds that contribute most to the antioxidant activity were shown to be verbascoside and rutin.

Iridoids as DNA topoisomerase I poisons.

The discovery of new topoisomerase I inhibitors is necessary since most of the antitumor drugs are targeted against type II and only a very few can specifically affect type I. Topoisomerase poisons generate toxic DNA damage by stabilization of the covalent DNA-topoisomerase cleavage complex and some have therapeutic efficacy in human cancer. Two iridoids, aucubin and geniposide, have shown antitumoral activities, but their activity against topoisomerase enzymes has not been tested. Here it was found that both compounds are able to stabilize covalent attachments of the topoisomerase I subunits to DNA at sites of DNA strand breaks, generating cleavage complexes intermediates so being active as poisons of topoisomerase I, but not topoisomerase II. This result points to DNA damage induced by topoisomerase I poisoning as one of the possible mechanisms by which these two iridoids have shown antitumoral activity, increasing interest in their possible use in cancer chemoprevention and therapy.

Antioxidant activity of methanol extracts obtained from Plantago species.

Antioxidative activities of methanol extracts from five Plantago species (P. afra, P. coronopus, P. lagopus, P. lanceolata, and P. serraria) were characterized by the DPPH scavenging test and the inhibition of Fe2+/ascorbate-induced lipid peroxidation on bovine brain liposomes. All extracts showed antioxidant activity in both methods. Whereas P. serraria exhibited the strongest activity as a DPPH scavenger, P. lanceolata and P. serraria were found to be the most active in the lipid peroxidation inhibition assay. The extracts were investigated regarding their composition by different colorimetric techniques, such as the content of total phenolic compounds by the Folin-Ciocalteu assay, flavonoids by AlCl3 reagent, phenylpropanoid glycosides (PPGs) by Arnow reagent, and iridoids by Trim-Hill assay. A high correlation was found between the scavenging potency and the total phenolic and phenylpropanoid content of the extracts but not between the lipid peroxidation potency and the extract composition. P. serraria is presented as a possible new source of natural antioxidants.

Cytotoxic effect of Plantago spp. on cancer cell lines.

Methanolic extracts from seven Plantago species used in traditional medicine for the treatment of cancer, were evaluated for cytotoxic activity against three human cancer cell lines recommended by the National Cancer Institute (NCI, USA). The results showed that Plantago species exhibited cytotoxic activity, showing a certain degree of selectivity against the tested cells in culture. Since the flavonoids are able to strongly inhibit the proliferation of human cancer cell lines, we have identified luteolin-7-O-beta-glucoside as major flavonoid present in most of the Plantago species. Also, we have evaluated this compound and its aglycon, luteolin, for their cytotoxic and DNA topoisomerase I poisons activities. These results could justify the traditional use of the Plantago species and topoisomerase-mediated DNA damage might be a possible mechanism by which flavonoids of Plantago exert their cytotoxicity potential.

Curcumin as a DNA topoisomerase II poison.

Curcumin, the major active component of the spice turmeric, is recognised as a safe compound with great potential for cancer chemoprevention and cancer therapy. It induces apoptosis, but its initiation mechanism remains poorly understood. Curcumin has been assessed on the human cancer cell lines, TK-10, MCF-7 and UACC-62, and their IC50 values were 12.16, 3.63, 4.28 microM respectively. The possibility of this compound being a topoisomerase II poison has also been studied and it was found that 50 microM of curcumin is active in a similar fashion to the antineoplastic agent etoposide. These results point to DNA damage induced by topoisomerase II poisoning as a possible mechanism by which curcumin initiates apoptosis, and increase the evidence suggesting its possible use in cancer therapy.