Acid-base and metal ion binding properties of 2-thiocytidine in aqueous solution

The thionucleoside 2-thiocytidine (C2S) occurs in nature in transfer RNAs; it receives attention in diverse fields like drug research and nanotechnology. By potentiometric pH titrations we measured the acidity constants of H(C2S)+ and the stability constants of the M(C2S)2+ and M(C2S−H)+ complexes (M2+=Zn2+, Cd2+), and we compared these results with those obtained previously for its parent nucleoside, cytidine (Cyd). Replacement of the (C2)=O unit by (C2)=S facilitates the release of the proton from (N3)H+ in H(C2S)+ (pK a = 3.44) somewhat, compared with H(Cyd)+ (pK a = 4.24). This moderate effect of about 0.8 pK units contrasts with the strong acidification of about 4 pK units of the (C4)NH2 group in C2S (pK a = 12.65) compared with Cyd (pK a≈16.7); the reason for this result is that the amino-thione tautomer, which dominates for the neutral C2S molecule, is transformed upon deprotonation into the imino-thioate form with the negative charge largely located on the sulfur. In the M(C2S)2+ complexes the (C2)S group is the primary binding site rather than N3 as is the case in the M(Cyd)2+ complexes, though owing to chelate formation N3 is to some extent still involved in metal ion binding. Similarly, in the Zn(C2S−H)+ and Cd(C2S−H)+ complexes the main metal ion binding site is the (C2)S− unit (formation degree above 99.99% compared with that of N3). However, again a large degree of chelate formation with N3 must be surmised for the M(C2S−H)+ species in accord with previous solid-state studies of related ligands. Upon metal ion binding, the deprotonation of the (C4)NH2 group (pK a = 12.65) is dramatically acidified (pK a≈3), confirming the very high stability of the M(C2S−H)+ complexes. To conclude, the hydrogen-bonding and metal ion complex forming capabilities of C2S differ strongly from those of its parent Cyd; this must have consequences for the properties of those RNAs which contain this thionucleosid

SARS-CoV-2 antibody response after mRNA vaccination in healthcare workers with and without previous COVID-19, a follow-up study from a university hospital in Poland during 6 months 2021

IntroductionHealthcare workers (HCWs) from the beginning of the pandemic have been at risk of exposure to SARS-CoV-2, so they were vaccinated as first.ObjectivesThe purpose of the study was to determine the level of antibodies against SARS-CoV-2 in HCWs before and after vaccination with mRNA preparations according to previous COVID- 19.Patients and methodsThe HCWs from the University Hospital in Krakow completed two surveys: the baseline survey before receiving the first dose of vaccine (in January 2021) and the follow-up survey in June 2021. In parallel, two blood samples were collected from each participant at baseline and at follow-up. Total anti-SARS-CoV-2 antibody levels were measured using the ECLIA technique.ResultsAt baseline, 41.1% of HCWs had positive antibody test results, and at follow-up, the vaccinated HCWs had almost 100 times higher antibody levels than the unvaccinated HCWs. Participants under 30 years of age had significantly higher antibody levels in June than older HCWs. Among participants with positive antibody test results in January, HCWs who had experienced asymptomatic COVID-19 had more than five times higher antibody levels in June than HCWs self-reported severe COVID-19. In total, 86.9% of HCWs received Comirnaty or Spikevax. The incidence rate of COVID-19 in the unvaccinated vs. vaccinated group was 13 times higher, 20.5% and 1.9% respectively.ConclusionsThese results confirm the effectiveness of vaccination in the prevention of COVID-19 in HCWs. It is worth getting vaccinated regardless of previous infection. Furthermore, vaccination among HCWs under 30 years of age induced more effective antibody production compared to older individuals

L’anglais de spécialité, une discipline universitaire transversale Specializing in English at university - a transversal discipline

L’anglais est probablement la langue qui s’est le plus étendue géographiquement au cours du XXe siècle et au cours du XXIe siècle, l’anglais sera sans doute le médium jouissant de la plus grande vitalité, si l’on en juge par le nombre toujours croissant de ses utilisateurs non-natifs. L’anglais s’impose ainsi comme le médium par excellence de la mondialisation et comme aucune nation n’a le loisir de se mettre en marge de cette mondialisation ni même d’échapper à ces effets, il n’est pas étonnant que la langue de Shakespeare soit la seconde langue étrangère la plus enseignée au monde

Selected factors affecting relative validity of Food Frequency Questionnaire SFFQ among preschool children : Krakow study

Wprowadzenie. Prowadzenie badań epidemiologicznych nad zależnością pomiędzy stanem zdrowia a sposobem żywienia wymaga, w pierwszej kolejności, trafnej oceny spożycia pokarmów oraz podaży składników pokarmowych. Cel. Celem badań była ocena wpływu wybranych czynników na trafność kwestionariusza częstości spożycia SFFQ w grupie dzieci przedszkolnych w wieku 3 lat ze środowiska krakowskiego. Materiał i metody. Do badań włączonych zostało 172 dzieci trzyletnich. W badaniach porównano podaż energii i wybranych składników pokarmowych, oszacowanych na podstawie półilościowego kwestionariusza częstości spożycia (SFFQ), z podażą tych składników, oszacowaną na podstawie trzech wywiadów 24-godz. Stopień zgodności pomiędzy badanymi metodami pomiaru określono na podstawie analizy skorygowanych współczynników korelacji Spearmana. Wyniki. Najwyższe współczynniki korelacji pomiędzy podażą oszacowaną na podstawie kwestionariusza SFFQ oraz trzech wywiadów 24-godz. zaobserwowano dla podaży witaminy B2 (RS=0,635) oraz wapnia (RS=0,605), natomiast najniższe dla podaży witamin PP oraz A (odpowiednio RS =0,344 i RS=0,355). Czynnikiem w największym stopniu wpływającym na trafność danych żywieniowych było uczęszczanie przez dziecko do przedszkola. Zaobserwowano również różnice w wielkości współczynników korelacji w zależności od poziomu wykształcenia i wieku matki oraz od masy ciała dziecka. Wnioski. Podaży energii oraz wszystkich badanych składników pokarmowych, oszacowana na podstawie kwestionariusza SFFQ, była znacząco wyższa w porównaniu do podaży wyliczonej na podstawie powtarzanych wywiadów 24-godz. Jednak trafność pomiaru podaży energii oraz podstawowych składników pokarmowych, mierzona współczynnikiem korelacji, była akceptowalna w odniesieniu do innych narzędzi wykorzystywanych do oceny żywienia dzieci.Background. Epidemiological studies of the relationship between health status and the mode of nutrition should be based primarily on valid assessment of the intake of food products and the intake of nutrients. Objective. The objective of the study was to assess the effect of selected demographic factors on the validity of semiquantitative Food Frequency Questionnaire (SFFQ) among three-year-old children from Krakow. Material and methods. The study group consisted of 172 three-year-old children. The intake of energy and selected nutrients assessed, based on the SFFQ, were compared with the intake from repeated 24-h recalls. The attenuated Spearman rank correlation was used to assess the level of compatibility between the two methods adjusted for the variability in the referent method. Results. The highest correlation between SFFQ and three 24-h recalls was found for vitamin B2 (RS =0.635) and calcium (RS =0.605) intake, while the lowest – vitamins PP and A (RS =0.344 and RS =0.355, respectively). It was found that the strongest factor influencing the level of compatibility of the two methods was attending a nursery school by child. Differences were also discovered in the values of correlation coefficients according to the level of education and age of the mother, and body weight of the child. Conclusions. The intake of energy and all the nutrients examined based on the SFFQ was significantly higher, compared to the intake assessed by repeated 24-h recalls. Nevertheless, the validity of measurement of intake of energy and basic nutrients measured by the correlation method were found to be at the acceptable level, compared to other instruments used for assessing food- nutrition among preschool children