Search

Bacterial infections pose a serious threat to human health. For many years, there has been a search for materials that would inhibit their development. It was decided to take a closer look at various elastomeric materials with the addition of chitosan. Mixtures based on silicone, silicone with a platinum catalyst, acrylonitrile-butadiene rubber, natural rubber, and ethylene-propylene-diene rubber were developed and tested for antibacterial and physico-mechanical properties. The dispersion of chitosan in the elastomer was also investigated using a scanning electron microscope. Of the tested mixtures, three were selected, characterised by the best antibacterial and physico-mechanical properties and a very good dispersion of chitosan in the matrix. The mixtures were based on silicone, silicone with a platinum catalyst and natural rubber. Tests were performed to measure the release of compounds into water for these mixtures. Furthermore, cytotoxicity with L929 cells and cytocompatibility in direct contact with MG63 cells were investigated for silicone samples. The results showed that these materials were not toxic to mammalian cells and supported their growth. The best bactericidal properties against E. coli and S. aureus strains compared to the other tested materials (>99.0-99.9% of killed bacteria) were shown by samples made of silicone and silicone with a platinum catalyst and added chitosan. At the same time, the best physico-mechanical properties were found for the samples with chitosan based on silicone with added platinum and natural rubber. Developed materials appeared to be good candidates for manufacturing medical equipment on which the adhesion and growth of bacteria should be prevented., (© 2024 Katarzyna Rucińska et al., published by Sciendo.)

Background: Preliminary research indicates that higher iron levels are associated with worse outcomes in patients with coronary artery disease., Aims: The study aimed to investigate the relationship between iron levels and the type and composition of coronary plaques., Methods: In patients with ≥1 coronary stenosis ≥50% on computed tomography angiography, iron levels, presence of high-risk plaque features, such as low-attenuation plaque (LAP), napkin-ring sign, positive remodeling, and spotty calcium, as well as type and plaque composition (calcified/fibrous/fibro-fatty/necrotic core) were evaluated. Fibro-fatty and necrotic core components were analyzed together as vulnerable component., Results: The study included 300 patients (191 men, 62.2 [23.0] years). Two thousand one hundred and eighty-four plaques were found (1201 calcified, 584 non-calcified, and 397 mixed). High-risk plaque was observed in 208 patients (107 LAP, 54 napkin-ring signs, 354 positive remodeling, and 281 spotty calcium). Patients with LAP had higher iron levels (P <0.0001). In univariable regression, LAP predictors were high iron levels (odds ratio [OR], 1.02; 95% CI, 1.00-1.03; P <0.0001), male sex (OR, 2.50, 95% CI, 1.40-4.46; P = 0.002), and hemoglobin (OR, 1.23; 95% CI, 1.01-1.49; P = 0.04). In multivariable regression, only iron and male sex were LAP predictors (OR, 1.02; 95% CI, 1.01-1.03; P = 0.0002, and OR, 2.41; 95% CI, 1.24-4.70; P = 0.009, respectively). The iron threshold for LAP prediction was >98 μg/dl (AUC 0.665; P <0.001), which corresponds with an OR of 3.2 (95% CI, 1.80-5.80; P = 0.0001) for LAP prediction. Higher iron correlated with more fibro-fatty (P = 0.01) and necrotic core (P = 0.02) components, with no relation to calcified and fibrous components. Higher iron was positively correlated with the percentage of vulnerable plaque component (P = 0.004)., Conclusions: Higher iron levels were associated with LAP presence and more vulnerable component of coronary atherosclerotic plaques.

Background: The Current European Society of Cardiology guidelines indicate specific target low-density lipoprotein cholesterol (LDL-C) levels for different cardiovascular risk categories in terms of prevention. However, the target for high-density lipoprotein cholesterol (HDL-C) and triglycerides has not been established., Aim: The study aims to investigate the associations betweenHDL-C,triglycerides, andcoronary plaque characteristics., Methods: This was a prospective single-center study with enrolled consecutive patients with newly diagnosed significant (≥1stenosis ≥50%) CAD on computed tomography coronary angiography (CTCA). Patients had lipids andCTCA analysis, including high-risk plaque (HRP) features: low-attenuation plaque (LAP), napkin-ring sign (NRS), positive remodeling (PR), and spotty calcium (SC), type of the plaque (calcified, noncalcified, mixed), and their composition (calcified, fibrous, fibro-fatty, necrotic core)., Results: The study included 300 patients (191 men, 66 [8] years). Sixty-six percent of them had lipid-lowering therapy. HRPwas found in 208 patients. There was no association between LDL-C, plaque composition, and HRP presence. There was a negative correlation between HDL-C, fibro-fatty and necrotic core plaque components (P = 0.0002, P = 0.0009). There was a positive correlation between triglycerides and necrotic core (P = 0.038). There were differences in HDL-C and triglycerides in patients with and without NRS (47 vs. 53 mg/dl, P = 0.0002 and 128 vs. 109 mg/dl, P = 0.02). In logistic regression, HDL-C (odds ratio [OR], 0.95;95% confidence interval [CI], 0.93-0.98; P <0.001), triglycerides (OR, 1.00; 95% CI, 1.00-1.01; P = 0.02), and male sex (OR, 3.04; 95% CI, 1.41-6.52; P = 0.004) were NRS predictors. In multivariable regression, only HDL-C (OR, 0.96; 95% CI, 0.93-0.99; P = 0.02) was an independent predictor of NRS., Conclusion: Lower HDL-C and higher triglycerides were associated with NRS presence and more necrotic core plaque components in coronary plaques in patients with newly diagnosed CAD.

Human cystatin C (HCC), an amyloidogenic protein, forms dimers and higher oligomers (trimers, tetramers and donut like large oligomers) via a domain-swapping mechanism. The aim of this study was the characterization of the HCC oligomeric states observed within the pH range from 2.2 to 10.0 and also in conditions promoting oligomerization. The HCC oligomeric forms obtained in different conditions were characterized using size exclusion chromatography, dynamic light scattering and small-angle X-ray scattering. The marked ability of HCC to form tetramers at low pH (2.3 or 3.0) and dimers at pH 4.0-5.0 was observed. HCC remains monomeric at pH levels above 6.0. Based on the SAXS data, the structure of the HCC tetramer was proposed. Changes in the environment (from acid to neutral) induced a breakdown of the HCC tetramers to dimers. The tetrameric forms of human cystatin C are formed by the association of the dimers without a domain-swapping mechanism. These observations were confirmed by their dissociation to dimers at pH 7.4.

New organophilic montmorillonites with oligomers of lactic acid and other compounds such as citric acid, stearic acid, maleic anhydride, pentaerythritol and ε-caprolactone were synthesized. They were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), elemental analysis and swelling capacity in water. In all tested composites, an increase in the montmorillonite interlayer distance resulting from intercalation of the modifying substance in the montmorillonite was found by means of XRD. Elemental analysis and FTIR showed that all of the tested samples contained an organic segment in the montmorillonite structure. TGA studies revealed that composites modified with lactic acid oligomers, stearic acid or ε-caprolactone had the highest thermal stability. They also exhibited the lowest swelling capacity which was 2-3 times lower than that for unmodified sodium montmorillonite. Some preliminary studies on the mechanical properties of PLA/modified montmorillonite are also presented and discussed.

In this review article we described the applications of various nanoparticles that can be used for photodynamic therapy (PDT), such as: plasmonic nanoparticles, quantum dots and upconversion nanoparticles. In comparison with typical organic photosensitizers such as hematoporphyrins, they exhibit higher photostability and resistance to enzymatic degradation, and hence, in some cases, they could replace organic photosensitizers in PDT therapy. It has also been found that the presence of plasmonic noble metal nanoparticles increases the efficiency of conjugated standard photosensitizers. Therefore, one can expect that, due to their very promising optical properties, plasmonic nanoparticles, plasmonic composites, and upconversion nanoconjugates will have a significant impact on the detection and treatment of cancer in the near future. Various methods of detecting the singlet oxygen produced are also reviewed., (Crown Copyright © 2019. Published by Elsevier B.V. All rights reserved.)