Prevalence and clinical impact of mono- and co-infections with endemic coronaviruses 229E, OC43, NL63, and HKU-1 during the COVID-19 pandemic.

Introduction: Endemic human coronaviruses (eHCoVs) are found worldwide and usually result in mild to moderate upper respiratory tract infections. They can lead to more severe illnesses such as croup, bronchiolitis, and pneumonia in vulnerable populations. During the coronavirus disease 2019 (COVID-19) pandemic, information on HCoV prevalence and incidence and clinical impact of co-infections of HCoV with SARS-CoV-2 was lacking. Objectives: Thus, this study aimed to determine the prevalence and clinical significance of infections caused by eHCoVs during the COVID-19 pandemic in Bulgaria. Methods: From January 2021 to December 2022, nasopharyngeal swabs of patients with acute upper or lower respiratory tract infections were tested for 17 respiratory viruses using multiplex real-time polymerase chain reaction assays. The clinical data and laboratory parameters of patients infected with respiratory viruses were analysed. Results: Of the 1375 patients screened, 24 (1.7 %) were positive for HCoVs, and 197 (14.3 %) were positive for eight other seasonal respiratory viruses. Five (0.7 %) of 740 patients positive for SARS-CoV-2 were co-infected with eHCoVs. Co-infected patients had a mean C-reactive protein level of 198.5 ± 2.12 mg/mL and a mean oxygen saturation of 82 ± 2.8 mmHg, while those in patients co-infected with SARS-CoV-2 and other respiratory viruses were 61.8 mg/mL and 92.8 ± 4.6 mmHg, respectively (p < 0.05). Pneumonia was diagnosed in 63.3 % of patients with HCoV infection and 6 % of patients positive for other seasonal respiratory viruses (p < 0.05). Patients with SARS-CoV-2 mono-infection stayed in hospital for an average of 5.8 ± 3.7 days, whereas the average hospital stay of patients with eHCoV and SARS-CoV-2 co-infection was 9 ± 1.4 days (p < 0.05). Conclusion: These findings indicate the low prevalence of eHCoVs and low co-infection rate between eHCoVs and SARS-CoV-2 during the COVID-19 pandemic in Bulgaria. Despite their low incidence, such mixed infections can cause severe signs that require oxygen therapy and longer hospital stays, underlining the need for targeted testing of severe COVID-19 cases to identify potential co-infections.

Contaminants in sediments: remobilisation and demobilisation.

In this study, the contaminated anoxic sediment of the Mulde reservoir (Saxony, Germany) was investigated. Several sediment cores were analysed for heavy metals and organic chemicals such as chlorobenzenes and DDTs. The comparison between anoxic and oxidised sediment cores showed the potential danger for heavy metal (Zn and Cd) remobilisation from sediment due to bioturbation or resuspension by flooding. Chemical sequential extraction was used to describe partitioning of heavy metals among different mineralogical components in the sediments. Results showed remobilisation of Zn and Cd from the sediments. The stable fraction (organic/sulfidic-bound) of Zn and Cd decreased from 10 to 3%, and from 35 to 5%, respectively. Simultaneously, the carbonate fraction increased from 3 to 12% for Cd and from 10 to 22% for Zn. Furthermore, the simulation of the diffusion of organic pollutants showed remobilisation of 1,4-dichlorobenzene. The results confirmed the necessity of sediment remediation in the reservoir. Capping seems to be a promising approach for a low-cost remediation.

[Nucleic acid synthesis and spatial organization of DNA in the presence of heparin and the quaternary ammonium salt of the conidin oligomer-25]. / Sintez nukleinovykh kislot i prostranstvennaia organizatsiiaDNK v prisutstvii geparina i chetvertichnoi ammoniinoi soli oligomera-25 konidina.

A comparative study of polyconidin effects in the replicative and transcription activity of hepatocyte DNA in intact animals, and on peculiarities of spatial organization DNA in the DNA complex with oligomer-25 conidin was carried out. It was shown that polyconidin binding to DNA results in "cross-linking". This process is accompanied by formation of liquid-crystalline dispersion without abnormal optical activity. Liquid crystals possess high density packing of DNA molecules complexed with quaternary ammonium salt of oligomer-25 conidin. The addition of heparin to liquid-crystalline dispersions or phases, destroys the structure of the DNA complex with quaternary ammonium salt of oligomer-25 conidin. As a result "free" DNA molecules appear, they form the cholesteric liquid-crystalline phase. An increase in transcription activity and synchronization of DNA synthesis in hepatocyte was demonstrated. A correlation between chromatin modification and biological activity of chromatin after formation of the DNA--oligomer-25 conidin complex is proposed.

[A comparative study of the antiheparin activity and acute toxicity of stellins]. / Sravnitel'noe issledovanie antigeparinovoi aktivnosti i ostroi toksichnosti stellinov.

The comparative study of the antiheparin activity and acute toxicity of the commercial preparation stellin and its homogeneous fractions was carried out. The summary preparation stellin along with a low antiheparin activity possessed a high toxicity explained by the content of ballast proteins of the nonprotamin nature. One of the homogeneous fractions--stellin B had the best antiheparin properties (heparin neutralizing ratio of 8:1 w:w) and a low toxicity due to a high content of arginine residues and a rigid macromolecular structure facilitating the interpolymer interaction with heparin.