García Esparza, María Ángeles

Ochratoxin A (OTA) is a common secondary metabolite of Aspergillus ochraceus, A. carbonarius, and Penicillium verrucosum. This mycotoxin is largely present as a contaminant in several cereal crops and human foodstuffs, including grapes, corn, nuts, and figs, among others. Preclinical studies have reported the involvement of OTA in metabolic, physiologic, and immunologic disturbances as well as in carcinogenesis. More recently, it has also been suggested that OTA may impair hippocampal neurogenesis in vivo and that this might be associated with learning and memory deficits. Furthermore, aside from its widely proven toxicity in tissues other than the brain, there is reason to believe that OTA contributes to neurodegenerative disorders. Thus, in this present in vivo study, we investigated this possibility by intraperitoneally (i.p.) administering 3.5 mg OTA/kg body weight to adult male mice to assess whether chronic exposure to this mycotoxin negatively affects cell viability in the dentate gyrus of the hippocampus. Immunohistochemistry assays showed that doses of 3.5 mg/kg caused a significant and dose-dependent reduction in repetitive cell division and branching (from 12% to 62%). Moreover, the number of countable astrocytes (p < 0.001), young neurons (p < 0.001), and mature neurons (p < 0.001) negatively correlated with the number of i.p. OTA injections administered (one, two, three, or six repeated doses). Our results show that OTA induced adverse effects in the hippocampus cells of adult mice brain tissue when administered in cumulative doses.

The efficacy of ethylene-vinyl alcohol copolymer films (EVOH) incorporating the essential oil components cinnamaldehyde (CINHO), citral (CIT), isoeugenol (IEG), or linalool (LIN) to control growth rate (GR) and production of T-2 and HT-2 toxins by Fusarium sporotrichioides cultured on oat grains under different temperature (28, 20, and 15 C) and water activity (aw) (0.99 and 0.96) regimes was assayed. GR in controls/treatments usually increased with increasing temperature, regardless of aw, but no significant differences concerning aw were found. Toxin production decreased with increasing temperature. The effectiveness of films to control fungal GR and toxin production was as follows: EVOH-CIT > EVOH-CINHO > EVOH-IEG > EVOH-LIN. With few exceptions, effective doses of EVOH-CIT, EVOH-CINHO, and EVOH-IEG films to reduce/inhibit GR by 50%, 90%, and 100% (ED50, ED90, and ED100) ranged from 515 to 3330 g/culture in Petri dish (25 g oat grains) depending on film type, aw, and temperature. ED90 and ED100 of EVOH-LIN were >3330 g/fungal culture. The potential of several machine learning (ML) methods to predict F. sporotrichioides GR and T-2 and HT-2 toxin production under the assayed conditions was comparatively analyzed. XGBoost and random forest attained the best performance, support vector machine and neural network ranked third or fourth depending on the output, while multiple linear regression proved to be the worst.

To assess the effects of a probiotic upon oral health indices in adolescents and to establish relationships between these indices and dietary habits and oral hygiene. Twenty-seven adolescents between 12 and 18 years of age were randomized into two groups. The study group received tablets containing Lactobacillus reuteri DSM 17938/ATCC 5289 for 28 days, while the control group received tablets without any bacteria. Streptococcus mutans, Lactobacillus sp., and salivary pH were assessed at baseline and at 7, 14, 21, 28, and 45 days. The plaque, gingivitis, and bleeding indices were recorded at baseline and at 14, 28, and 45 days. Dietary and oral hygiene habits were also evaluated by means of a questionnaire. A less marked rise in S. mutans was recorded in the study group. Improvements were observed in terms of plaque, gingivitis, and bleeding, though statistical significance was not reached. Oral pH increased in the study group, though not to a significant degree. Poorer eating habits were significantly correlated to increased plaque. The study parameters decreased with the two strains of L. reuteri DSM 17938 and ATCC PTA 5289, though the results failed to reach statistical.

The aim of this study was to evaluate the infuence of boron-nitride nanotubes (BNNTs) on the properties of resin-based light-curing dental sealants (RBSs) when incorporated at diferent concentration. RBSs were formulated using methacrylate monomers (90 wt.% TEGDMA, 10 wt.% BisGMA). BNNTs were added to the resin blend at 0.1 wt.% and 0.2 wt.%. A Control group without fller was also designed. Degree of conversion, ultimate tensile strength, contact angle, surface free energy, surface roughness and color of the RBSs were evaluated for the tested materials. Their cytotoxicity and mineral deposition ability (Bioactivity) were also assessed. A suitable degree of conversion, no efect in mechanical properties and no cytotoxic efect was observed for the experimental materials. Moreover, the surface free energy and the surface roughness decreased with the addition of BNNTs. While the color analysis showed no diference between specimens containing BNNTs and the control group. Mineral deposition occurred in all specimens containing BNNTs after 7d. In conclusion, the incorporation of BNNTs may provide bioactivity to resin-based dental sealants and reduce their surface free energy.

Tau has a wide variety of essential functions in the brain, but this protein also plays a determining role in the development of Alzheimer's disease (AD) and other neurodegenerative diseases called tauopathies. This is due to its abnormal aggregation and the subsequent formation of neurofibrillary tangles. Tau hyperphosphorylation appears to be a critical step in its transformation into an aggregated protein. However, the exact process, including the cellular events that trigger it, remains unclear. In this study, we employed immunocytochemistry assays on hippocampal sections from AD cases and from tauopathy cases (Braak stage III) with no evidence of cognitive decline, and the P301S mouse model to investigate the colocalization patterns of Tau phosphorylated (p) at specific residues (S202-T205, S214, and T231) within the proline-rich region. Our results show pyramidal neurons in the hippocampus of P301S mice in which Tau is intensely phosphorylated at residues S202 and T205 (recognized by the AT8 antibody), but with no detectable phosphorylation at S214 or T231. These non-colocalizing neurons displayed intensely labeled aggregated pTau deposits distributed through the soma and dendritic processes. However, most of the hippocampal pyramidal neurons are labeled with pTauS214 or pTauT231 antibodies and typically showed a homogeneous and diffuse pTau distribution (not aggregated). This different labeling likely reflects a Tau conformational step, potentially related to the transition from a diffuse tau phosphorylation phenotype (Type 2) into an NFT-like or Type 1 phenotype. We further observed that dendrites of CA3 pyramidal cells are intensely labeled with pTau214 in the stratum lucidum, but not with AT8 or pTauT231. By contrast, analysis of tissue from AD patients or other human tauopathy cases (Braak stage III) with no evidence of cognitive decline revealed extensive colocalization with both antibody combinations in CA1. The complete or mature tangle development may follow a different mechanism in the P301S mouse model or may require more time to achieve the maturity state found in AD cases. Further studies would be necessary to address this question.