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Toxicological studies are important to investigate the genotoxic effects of various substances. Allium cepa can be used as test model for this purpose. This review summarizes the scope and applications for this A. cepa test model. For this, an up-to-date (April 2023) literature search was made in the Science Direct, PubMed, and Web of Science databases to find published evidence on studies performed using A. cepa as a test model. Out of 3,748 studies, 74 fit the inclusion criteria. The results showed that the use of the test model A. cepa contributed considerably to measuring the toxicological potential of plant extracts, proving the efficacy of the test as a potent bioindicator of toxic effects. In addition, 27 studies used more than one test system to verify the toxicological potential of extracts and fractions. Studies have shown that the A. cepa model has the potential to replace other test systems that make use of animals and cell cultures, besides having other advantages such as low cost, ease of execution, and good conditions for the observation of chromosomes. In conclusion, the A. cepa test can be considered one of the potential biomonitoring systems in toxicological studies of crude extracts., (© 2024 Wiley‐VCH GmbH.)

Bottom-up mechanochemical synthesis (BUMS) has been demonstrated to be an efficient approach for the preparation of metal nanoparticles (NPs), protected by surface agents or anchored on solid supports. However, there are limitations, such as precise size and morphological control, due to a lack of knowledge about the mechanically induced processes of NP formation under milling. In this article, we further investigate the BUMS of AuNPs. Using SiO 2 as a solid support, we studied the effect of typical reducing agents, namely NaBH 4 , L-ascorbic acid, and hydroquinone (HQ), on the conversion of a Au III source. XANES showed that HQ is the strongest reducing agent under our experimental conditions, leading to the quantitative conversion of gold salt in a few minutes. Interestingly, even when HQ was used in sub-stoichiometric amounts, Au III could be reduced to ratios higher than 85% after two minutes of milling. Investigations into the byproducts by 1 H NMR and GC-FID/MS enabled the identification HQ regeneration and the formation of its derivatives. We mainly focused on benzoquinone (BQ), which is the product of the oxidation of HQ as it reduces the gold salt. We could demonstrate that HQ is regenerated from BQ exclusively under milling and acidic conditions. The regenerated HQ and other HQ-chlorinated molecules could then reduce gold-oxidized species, leading to higher conversions and economy of reactants. Our study highlights the intriguing and complex mechanisms of mechanochemical systems, in addition to fostering the atom and energy economy side of mechanochemical means to produce metal nanoparticles.

Microplastics are widespread pollutants in the environment and are considered a global pollution problem. Microplastics mostly originate from larger plastics and due to environmental conditions are undergoing constant fragmentation processes. It is important to understand the fragmentation pathways, since they play a key role in the fate of the particles, and also directly influence toxicity. Amphipods are potential inducers of plastic debris fragmentation. Here, Hyalella azteca was exposed to different concentrations (540, 2700, 5400 items/L) of 24.5 µm polystyrene microplastics (PS-MP) for 7 days. After exposure, oxidative stress, particle size reduction, and mortality were checked. No significant mortality was seen in any of the treatments, although changes were recorded in all enzymatic biomarkers analyzed. It was observed that throughout the ingestion and egestion of PS-MP by H. azteca, particles underwent intense fragmentation, presenting a final size up to 25.3% smaller than the initial size. The fragmentation over time (24, 72, 120, 168 h) was verified and the results showed a constant reduction in average particle size indicating that H. azteca are able to induce PS-MP fragmentation. This process may facilitate bioaccumulation and trophic particle transfer., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Over 3,000 yearly cases of Visceral Leishmaniasis (VL) are reported in Brazil. Brazilian Public Health System provides universal free access to antileishmania therapeutic options: Meglumine Antimoniate, Amphotericin B deoxycholate, and Liposomal Amphotericin B. Even though Amphotericin formulations have been advised for severe disease, this recommendation is mostly based on the opinion of experts and on analogy with studies conducted in other countries. Presently, there are two ongoing multicenter clinical trials comparing the efficacy and safety of the available therapeutic options. Some other issues require further clarification, such as severity markers and the approach to VL/AIDS coinfection. Brazil is facing the challenge of providing access to diagnosis and adequate treatment, in order to avoid VL-related deaths.

Methicillin-resistant Staphylococcus aureus (MRSA) is an important agent of colonization and infection in burn units. In order to identify risk factors for MRSA acquisition in a Brazilian burn unit, we performed two retrospective studies. In the first ("cohort" study), 175 patients who were not colonized with MRSA on admission were followed to assess risk factors for MRSA acquisition. In the second ("case-case-control" study), 143 individuals from the previous study who were negative for both MRSA and Methicillin-susceptible S. aureus (MSSA) on admission were followed. Case-control studies were performed to investigate risk factors for MRSA and MSSA acquisition. MRSA and MSSA were recovered from 75 and 23 patients, respectively. In the "cohort" study, only the number of wound excisions (Odds Ratio [OR]=1.55, 95% Confidence Interval [CI]=1.21-1.98, P=0.001) was associated with MRSA acquisition. In the "case-case-control" study, burns involving head (OR=3.43, 95%CI=1.50-7.81, P=0.003) and the number of wound excisions (OR=1.83, 95%CI=1.27-2.63, P=0.001) were significant risk factors for MRSA. Burns involving perineum were negatively associated with MSSA acquisition (OR=0.16, 95%CI=0.03-0.75, P=0.02). In conclusion, the acquisition of MRSA was related to the site of the burn and to the surgical manipulation of tissues, but not to the use of antimicrobials.

To obtain a mathematical equation that could estimate the length of the intermembranous part of the vocal fold as a function of body height and gender, we removed the larynges from 39 cadavers (22 men and 17 women) after recording the subject's height, age, and cause of death. The dimensions of the vocal folds were determined with a digital pachymeter. The following equations were obtained: y = 0.18x - 15.8 for men and y = 0.24x - 28.1 for women, where y is the length of the intermembranous part of the vocal folds in millimeters and x is the height of the individual in centimeters. We conclude that it is possible to estimate the normal expected length of the intermembranous portion of the male and female vocal folds on the basis of body height.

Objectives: To describe the arrangement of collagen fibers in the lamina propria of the human vocal fold., Study Design: Analysis of the lamina propria of the vocal fold obtained from human cadavers., Methods: The Picrosirius-polarization method was used to visualize collagen fibers., Results: Analysis of 20 human vocal folds by the Picrosirius-polarization method permitted the visualization of two fiber populations arranged in three layers in the lamina propria: two layers of thick, strongly birefringent collagen fibers (collagen type I), one immediately below the epithelium and another more dense layer in the deep region superficially to the vocal muscle, penetrating between muscle fibers. The third layer consisted of fine, weakly birefringent fibers (collagen type III) located between the two layers of thick fibers. In addition, the collagen fibers in the lamina propria showed an intertwined network arrangement in the form of a "wicker basket.", Conclusions: This basket-like configuration better explains how the vocal fold is able to stretch even though it contains nonstretchable fibers and to modulate the frequency of the voice under the action of the intrinsic musculature of the larynx. Segmental areas of disarray of the basket-like structure of the collagen layers were systematically observed in older patients. Thus, it is possible that vocal alterations occurring in the elderly might be the result of a loss of histoarchitectural arrangement of the collagen system and its relationship with the lamina propria and underlying musculature.