The Influence of Bloom Index, Endotoxin Levels and Polyethylene Glycol Succinimidyl Glutarate Crosslinking on the Physicochemical and Biological Properties of Gelatin Biomaterials

In the medical device sector, bloom index and residual endotoxins should be controlled, as they are crucial regulators of the device’s physicochemical and biological properties. It is also imperative to identify a suitable crosslinking method to increase mechanical integrity, without jeopardising cellular functions of gelatin-based devices. Herein, gelatin preparations with variable bloom index and endotoxin levels were used to fabricate non-crosslinked and polyethylene glycol succinimidyl glutarate crosslinked gelatin scaffolds, the physicochemical and biological properties of which were subsequently assessed. Gelatin preparations with low bloom index resulted in hydrogels with significantly (p < 0.05) lower compression stress, elastic modulus and resistance to enzymatic degradation, and significantly higher (p < 0.05) free amine content than gelatin preparations with high bloom index. Gelatin preparations with high endotoxin levels resulted in films that induced significantly (p < 0.05) higher macrophage clusters than gelatin preparations with low endotoxin level. Our data suggest that the bloom index modulates the physicochemical properties, and the endotoxin content regulates the biological response of gelatin biomaterials. Although polyethylene glycol succinimidyl glutarate crosslinking significantly (p < 0.05) increased compression stress, elastic modulus and resistance to enzymatic degradation, and significantly (p < 0.05) decreased free amine content, at the concentration used, it did not provide sufficient structural integrity to support cell culture. Therefore, the quest for the optimal gelatin crosslinker continues.

Glycation Markers in the Geriatrics Patients

Background: Medical care for geriatric patients is a great challenge, mainly due to overlapping various deficits relevant to physiologic ageing with numerous coexisting diseases, of which the most common are diabetes mellitus and atherosclerosis. In case of diabetes, glycation process is intensified, which accelerates atherosclerosis development and diabetic complications. Our goal was to investigate the relationship between the classical biochemical parameters of diabetes and atherosclerosis (fasting glucose, glycated hemoglobin (HbA1c), low and high density lipoproteins (LDL, HDL), triglycerides, etc.), as well as parameters which may indicate a nephropathy (creatinine, glomerular filtration rate – GFR), and the parameters strictly related to glycation. Methods: We analyzed the patients' serum concentration of fluorescent glycation products, concentration of soluble receptor for advanced glycation products (sRAGE), lipoprotein receptor-1 (LOX-1), galectin 3 (GAL3), scavenger receptor class A (SR-A) and scavenger receptor class B (SR-BI), as well as the level of lipid peroxidation and free amine content. Results: Among the identified correlations, the most interesting are the following : sRAGE with triglycerides (r = 0.47); sRAGE with SR-BI (r=0.47); SR-BI with LOX-1 (r=0.31), and SR-BI with HDL (r=-0.30). It has been shown that pentosidine and fluorescent AGEs as well as reactive free amine contents are significantly higher in elderly patients with ischemic heart disease. Fluorescent AGEs and pentosidine are also significantly higher in patients with arterial hypertension. The influence of diabetes therapy on parameters related to peroxidation and glycation was also analyzed. Malondialdehyde turned to be higher in patients with diabetes mellitus type 2 not treated with insulin or metformin than in those treated with both medications (p=0.052). GAL3 was found to be lower both in persons without diabetes and in diabetics treated with metformin (p=0.005). LOX1 was higher in diabetic patients not treated with metformin or insulin, and lowest in diabetics treated with both insulin and metformin, with the effect of metformin reducing LOX1 levels (p=0.039). Conclusions: Our results were the basis for a discussion about the diagnostic value in clinial practice of LOX-1 and GAL3 in geriatric patients with diabetes and also provide grounds for inferring the therapeutic benefits of insulin and metformin treatment.

New Chloramphenicol Derivatives with a Modified Dichloroacetyl Tail as Potential Antimicrobial Agents

To combat the dangerously increasing pathogenic resistance to antibiotics, we developed new pharmacophores by chemically modifying a known antibiotic, which remains to this day the most familiar and productive way for novel antibiotic development. We used as a starting material the chloramphenicol base, which is the free amine group counterpart of the known chloramphenicol molecule antibiotic upon removal of its dichloroacetyl tail. To this free amine group, we tethered alpha- and beta-amino acids, mainly glycine, lysine, histidine, ornithine and/or beta-alanine. Furthermore, we introduced additional modifications to the newly incorporated amine groups either with protecting groups triphenylmethyl- (Trt) and tert-butoxycarbonyl- (Boc) or with the dichloroacetic group found also in the chloramphenicol molecule. The antimicrobial activity of all compounds was tested both in vivo and in vitro, and according to the results, the bis-dichloroacetyl derivative of ornithine displayed the highest antimicrobial activity both in vivo and in vitro and seems to be a dynamic new pharmacophore with room for further modification and development.

The influence of animal species, gender and tissue on the structural, biophysical, biochemical and biological properties of collagen sponges

Although collagen type I is extensively used in biomedicine, no study to-date has assessed how the properties of the produced scaffolds are affected as a function of species, gender and tissue from which the collagen was extracted. Herein, we extracted and characterised collagen from porcine and bovine, male and female and skin and tendon tissues and we subsequently fabricated and assessed the structural, biophysical, biochemical and biological properties of collagen sponges. All collagen preparations were of similar purity and free-amine content (p > 0.05). In general, the porcine groups yielded more collagen; had higher (p < 0.05) denaturation temperature and resistance to enzymatic degradation; and lower (p < 0.05) swelling ratio and compression stress and modulus than the bovine groups of the same gender and tissue. All collagen preparations supported growth of human dermal fibroblasts and exhibited similar biological response to human THP-1 monocytes. These results further illustrate the need for standardisation of collagen preparations for the development of reproducible collagen-based devices.

SARS-CoV-2 ARDS by NLRP3 & ICU Treatment

4,4′-Diaminodiphenyl sulfone (Dapsone, DDS) targets COVID-19 as a key to ending the current ARDS by SARS-CoV-2. Dapsone is an inflammasome competitor commonly used in combination with clofazimine-rifampicin for the treatment of leprosy. Dapsone binds to myeloperoxidase and regulates hypochlorite production, thereby reducing the inflammatory response of cells and has a structure that can reduce the sulfur radical production rate by electron charge transfer because they are structurally similar to methionine sulfoxide. Nucleophilic properties of dapsone compete with ubiquitin by attacking a ubiquitin (Ub)-conjugating enzyme (E2)–Ub thioester linkage. The best-described sites are the amine-containing internal lysine residues and the free amine of the polypeptide backbone’s N-terminus. ORF8b activates NLRP3 through direct interaction of the AT-rich repeat domain of NLRP3. Nucleophilic properties of DDS compete with NLRP3. Dapsone’s four mechanisms have treated ARDS and prevented SARS-CoV-2 infection.

The Use of Non-Saccharomyces Yeast and Enzymes in Beer Production

The objective of this paper was to test the potential of selected non-Saccharomyces strains for beer production, by using Saccharomyces cerevisiae as a control sample. For some of variants brewing enzymes were added to wort to increase the content of fermentable sugars. The non-Saccharomyces yeasts differed in the fermentation process rate. The basic beer physiochemical parameters were assessed, including: alcohol content, extract, free amino nitrogen, sugars, acidity, colour, and the profile of volatile compounds and metal ions. The use of enzymes caused an increase in alcohol and fusel alcohols concentration in beers obtained. Total acidity, free amine nitrogen content, colour and sugar content indicated that the tested non-Saccharomyces yeast allowed obtaining beers with the proper analytical parameters.

Functionalization and Modification of Bitumen by Silica Nanoparticles

A study on the effect of silica nanoparticles (SNPs) dispersion in bitumen is herein reported. First, the size of the nanoparticles was finely tuned by controlling the experimental conditions during their synthesis, obtaining spherical SNPs with diameter ranging from 95 up to 900 nm. Subsequently, SNPs were embedded with peripheral amine groups by using APTES (3-aminopropyltriethoxysilane) as functionalized agent (NH2@SNP), and ultimately long alkyl chains were grafted by reacting the free amine with an alkylated aldehyde (C14N@SNP). All SNPs (ca. 1 wt%.) were dispersed in bitumen to probe their effect on the rheological properties of bitumen. No significant change in the thermorheological properties of bitumen was observed upon varying the size of the SNPs. Slight improvement was observed when using NH2@SNPs, while the best results were obtained by using C14N@SNPs, showing the crucial role that hydrophobic substituents play in bitumen binders which leads to significant improvements.