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Chitosan is a very promising material for tissue model printing. It is also known that the introduction of chemical modifications to the structure of the material in the form of methacrylate groups makes it very attractive for application in the bioprinting of tissue models. The aim of this work is to study the characteristics of biomaterials containing chitosan (BCH) and its methacrylated equivalent (BCM) in order to identify differences in their usefulness in 3D bioprinting technology. It has been shown that the BCM material containing methacrylic chitosan is three times more viscous than its non-methacrylated BCH counterpart. Additionally, the BCM material is characterized by stability in a larger range of stresses, as well as better printability, resolution, and fiber stability. The BCM material has higher mechanical parameters, both mechanical strength and Young's modulus, than the BCH material. Both materials are ideal for bioprinting, but BCM has unique rheological properties and significant mechanical resistance. In addition, biological tests have shown that the addition of chitosan to biomaterials increases cell proliferation, particularly in 3D-printed models. Moreover, modification in the form of methacrylation encourages reduced toxicity of the biomaterial in 3D constructs. Our investigation demonstrates the suitability of a chitosan-enhanced biomaterial, specifically methacrylate-treated, for application in tissue engineering, and particularly for tissues requiring resistance to high stress, i.e., vascular or cartilage models.

ABSTRACT The study describes three clinical cases of infection with Avibacterium spp.. In case no. 1, respiratory clinical signs and high mortality (0.7-4.2% daily; total 21.2%) in Ross 308 broiler chickens were shown to be caused by coinfection with sequence type 9 of O. rhinotracheale presumptive serotype A and A. paragallinarum presumptive serotype B. The identical (pulsed-field gel electrophoresis) restriction pattern (pulsotype) of seven A. paragallinarum isolates indicated that infectious coryza in broilers was caused by the same clone. In cases 2 and 3, sudden increased deaths in Ross 308 broiler breeders (especially males) with lesions in the endocardium (valvular or mural endocarditis) were shown to be caused by A. endocarditis . Among nine antibiotics tested, florfenicol was the only antibiotic to which all A. paragallinarum and O. rhinotracheale isolates were susceptible. Out of the eight antibiotics tested, 11 A. endocarditis isolates from both clinical cases of infective endocarditis were susceptible to penicillin, amoxicillin, doxycycline and florfenicol. The A. endocarditis isolates tested in both clinical cases had different PFGE patterns (pulsotypes), but identical within a case. The causes of infectious coryza and infective endocarditis in the cases presented have not been determined. In the prevention of infectious diseases in large-scale livestock farming, it is very important to follow the rules of biosecurity.

Competing Interests: The authors declare no conflict of interest.

Competing Interests: The authors declare no conflict of interest.

Paraneoplastic syndromes are a group of rare clinical conditions characterized by a diverse array of systemic manifestations that arise in association with malignant tumours, often due to the production of bioactive substances by the tumour or an autoimmune response to the tumour. Melanoma, a malignant skin neoplasm originating from melanocytes, has been associated with various paraneoplastic syndromes. This paper provides an overview of the key paraneoplastic syndromes observed in patients with melanoma. Paraneoplastic syndromes in melanoma can manifest with neurological, dermatological, endocrine, haematological, and rheumatological symptoms, among others. Melanoma-associated retinopathy was the most reported paraneoplastic syndrome; this entity is characterized by a spectrum of retinal abnormalities. Paraneoplastic neurological syndromes, such as paraneoplastic encephalitis and paraneoplastic cerebellar degeneration, are among the most frequently reported. The pathophysiology of paraneoplastic syndromes often involves the production of autoantibodies against neuronal or tumour antigens, immune-mediated reactions, or the release of cytokines and growth factors from the tumour. Management strategies for paraneoplastic syndromes associated with melanoma primarily focus on treating the underlying malignancy, which may lead to resolution or improvement of the paraneoplastic manifestations. Immune-modulating therapies, including corticosteroids, intravenous immunoglobulins, and plasmapheresis, may be considered in selected cases to ameliorate symptoms and suppress the autoimmune response. In conclusion, paraneoplastic syndromes in patients with melanoma are a complex and diverse group of clinical entities with a broad range of presentations. Further research is needed to enhance our understanding of the mechanisms and therapeutic options for paraneoplastic syndromes associated with melanoma., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 Termedia Sp. z o. o.)

Currently, a major challenge in material engineering is to develop a cell-safe biomaterial with significant utility in processing technology such as 3D bioprinting. The main goal of this work was to optimize the composition of a new graphene oxide (GO)-based bioink containing additional extracellular matrix (ECM) with unique properties that may find application in 3D bioprinting of biomimetic scaffolds. The experimental work evaluated functional properties such as viscosity and complex modulus, printability, mechanical strength, elasticity, degradation and absorbability, as well as biological properties such as cytotoxicity and cell response after exposure to a biomaterial. The findings demonstrated that the inclusion of GO had no substantial impact on the rheological properties and printability, but it did enhance the mechanical properties. This enhancement is crucial for the advancement of 3D scaffolds that are resilient to deformation and promote their utilization in tissue engineering investigations. Furthermore, GO-based hydrogels exhibited much greater swelling, absorbability and degradation compared to non-GO-based bioink. Additionally, these biomaterials showed lower cytotoxicity. Due to its properties, it is recommended to use bioink containing GO for bioprinting functional tissue models with the vascular system, e.g., for testing drugs or hard tissue models.

Goose erysipelas is a serious problem in waterfowl breeding in Poland. However, knowledge of the characteristics of Erysipelothrix rhusiopathiae strains causing this disease is limited. In this study, the antimicrobial susceptibility and serotypes of four E. rhusiopathiae strains from domestic geese were determined, and their whole-genome sequences (WGSs) were analyzed to detect resistance genes, integrative and conjugative elements (ICEs), and prophage DNA. Sequence type and the presence of resistance genes and transposons were compared with 363 publicly available E. rhusiopathiae strains, as well as 13 strains of other Erysipelothrix species. Four strains tested represented serotypes 2 and 5 and the MLST groups ST 4, 32, 242, and 243. Their assembled circular genomes ranged from 1.8 to 1.9 kb with a GC content of 36-37%; a small plasmid was detected in strain 1023. Strains 1023 and 267 were multidrug-resistant. The resistance genes detected in the genome of strain 1023 were erm47 , tetM , and lsaE-lnuB-ant(6)-Ia- s pw cluster, while strain 267 contained the tetM and ermB genes. Mutations in the gyrA gene were detected in both strains. The tetM gene was embedded in a Tn 916 -like transposon, which in strain 1023, together with the other resistance genes, was located on a large integrative and conjugative-like element of 130 kb designated as ICEEr1023. A minor integrative element of 74 kb was identified in strain 1012 (ICEEr1012). This work contributes to knowledge about the characteristics of E. rhusiopathiae bacteria and, for the first time, reveals the occurrence of erm47 and ermB resistance genes in strains of this species. Phage infection appears to be responsible for the introduction of the ermB gene into the genome of strain 267, while ICEs most likely play a key role in the spread of the other resistance genes identified in E. rhusiopathiae.

Competing Interests: The authors declare no conflict of interest.

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that has gained increasing attention in the field of dermatology due to its multifaceted role in skin health and disease. This review provides a comprehensive overview of the current state of knowledge regarding the AHR and its implications in dermatological conditions. The AHR is well known for its involvement in xenobiotic metabolism, particularly in response to polycyclic aromatic hydrocarbons and dioxins. However, recent research has unveiled its pivotal role in the skin immune response, barrier function, and homeostasis. The AHR signalling pathway is intricately linked to various dermatological disorders, including psoriasis, atopic dermatitis, acne and hidradenitis suppurativa. In this review, we delve into the molecular mechanisms through which AHR activation influences skin physiology and highlight how dysregulation can lead to pathological conditions. Moreover, we discuss the emerging therapeutic potential of AHR modulators in the treatment of skin diseases. In conclusion, the AHR is a pivotal player in dermatology, with a multifaceted role in skin physiology and pathology. Understanding the intricacies of AHR signalling in the skin offers promising avenues for the development of novel therapies and preventive strategies for various dermatological conditions. Further research is warranted to elucidate the full scope of AHR's contributions to dermatology and its potential as a therapeutic target., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 Termedia Sp. z o. o.)

Background and Purpose: Adamantanes were listed as an interesting option as an early intervention against COVID-19. We aimed to evaluate the effectiveness of amantadine in preventing the progression of COVID-19 and its neurological sequelae., Methods: Unvaccinated patients with confirmed SARS-CoV-2 infection within 5 days were enrolled. Subjects were randomized (50:50) to amantadine (AMD; 100 mg twice daily) or placebo (PLB) for 14 days. The Ordinal Scale for Clinical Improvement of the World Health Organization (OSCI-WHO) was the primary measure. Secondary endpoints included assessment for fatigue; depression, disorders of smell and taste, and sleepiness on Days 1 and 15., Results: We enrolled 99 patients (49 AMD and 50 PLB). Disease progression (OSCI-WHO = 4) was observed in 6% (AMD) and 8% (PLB) patients (p > 0.05) with further deterioration (OSCI-WHO〉4) in 0% (AMD) and 8% (PLB) patients (p > 0.05). Complete recovery on Day 15 was 60% higher in the AMD compared with the PLB group (p = 0.025). There was improvement in taste (AMD: p = 0.003; PLB: p = 0.0001) and smell (AMD: p = 0.005; PLB: p = 0.0004) but not in fatigue in both groups. Improvement was observed in the AMD (p = 0.010) but not in the PLB group (p = 0.058) when assessing depression as well as sleepiness (AMD: p = 0.0002; PLB: p = 0.341). There was one death in the PLB group (2.0%) and none in the AMD group (p > 0.05) until Day 210. Overall, the drug was well tolerated., Conclusion: The central effects of amantadine on the nervous system with reduction of sleepiness and depression might have had a supportive effect on faster recovery in early COVID-19 patients., (© 2023 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)