Preceding anti-spike IgG levels predicted risk and severity of COVID-19 during the Omicron-dominant wave in Santa Fe city, Argentina.

The SARS-CoV-2 Omicron variant has increased infectivity and immune escape compared with previous variants, and caused the surge of massive COVID-19 waves globally. Despite a vast majority (~90%) of the population of Santa Fe city, Argentina had been vaccinated and/or had been infected by SARS-CoV-2 when Omicron emerged, the epidemic wave that followed its arrival was by far the largest one experienced in the city. A serosurvey conducted prior to the arrival of Omicron allowed to assess the acquired humoral defences preceding the wave and to conduct a longitudinal study to provide individual-level real-world data linking antibody levels and protection against COVID-19 during the wave. A very large proportion of 1455 sampled individuals had immunological memory against COVID-19 at the arrival of Omicron (almost 90%), and about half (48.9%) had high anti-spike immunoglobulin G levels (>200 UI/ml). However, the antibody titres varied greatly among the participants, and such variability depended mainly on the vaccine platform received, on having had COVID-19 previously and on the number of days elapsed since last antigen exposure (vaccine shot or natural infection). A follow-up of 514 participants provided real-world evidence of antibody-mediated protection against COVID-19 during a period of high risk of exposure to an immune-escaping highly transmissible variant. Pre-wave antibody titres were strongly negatively associated with COVID-19 incidence and severity of symptoms during the wave. Also, receiving a vaccine shot during the follow-up period reduced the COVID-19 risk drastically (15-fold). These results highlight the importance of maintaining high defences through vaccination at times of high risk of exposure to immune-escaping variants.

Antithrombotic Activity of Brewers' Spent Grain Peptides and their Effects on Blood Coagulation Pathways.

Antithrombotic activity of brewers' spent grain peptides before and after simulated gastrointestinal digestion and their effects on blood coagulation pathways were evaluated. Two hydrolysates were produced using sequential enzymatic systems: alkaline protease + Flavourzyme (AF) and neutral protease + Flavourzyme (PF). Simulation of gastrointestinal digestion of AF and PF hydrolysates was made using porcine pepsin and pancreatin enzymes, obtaining the corresponding digested samples: AFD and PFD, respectively. Peptides were fractionated by ultrafiltration using a 1 kDa cut-off membrane. Hydrolysates had peptides with medium and low molecular weights (2100 and 500 Da, respectively), and Glu, Asp, Leu, Ala, and Phe were the most abundant amino acids. Gastrointestinal digested hydrolysates presented high proportion of small peptides (~500 Da), and higher amount of Val, Tyr, and Phe than hydrolysates. Mass spectrum (HDMS Q-TOF) of AFD-ultrafiltered fraction <1 kDa exhibited peptides from 500 to 1000 Da, which are not present in AF. PFD showed the generation of new peptides from 430 to 1070 Da. All samples showed thrombin inhibitory activity. However, no effect was observed on prothrombin time. Peptides <1 kDa from hydrolysates and digested samples delayed thrombin and thromboplastin time respect to the control (~63%). Also the samples showed thrombin inhibitory activity at common pathway level. Thus, brewers' spent grain peptides exerted their antithrombotic activity by inhibiting the intrinsic and common pathways of blood coagulation. This is the first report to demonstrate that brewers' spent grain peptides are able to delay clotting time after simulated gastrointestinal digestion.

Valores normales de alfa feto proteína por ensayo inmunorradiométrico durante el primer año de vida / Alpha fetoprotein reference levels during the first year of life

El propósito de este estudio fue determinar la variación de los niveles séricos de alfa fetoproteína (AFP), durante el primer año de vida, utilizando un ensayo inmunorradiométrico. Se realizó la estadística descriptiva en cada período estudiado. Se determinó el tipo de correlación existente entre la AFP sérica y el tiempo. Durante el primer mes de vida se observó una correlación lineal: r = - 0,957; mientras que entre el 2º y 12º mes los datos se ajustaron a una potencial de la forma y = axb : r = 0,989. Los niveles promedios de AFP al primer año de vida fueron similares a los del adulto normal, no obstante un 10 por ciento de los niños estudiados presentó valores más elevados. Los rangos de normalidad obtenidos permitiran una mejor discriminación entre normales y patológicos, cuando sea necesaria la utilización de AFP como un elemento más para diagnosticar neoplasias embrionarias, en la etapa de vida estudiada

Valores normales de alfa feto proteína por ensayo inmunorradiométrico durante el primer año de vida / Alpha fetoprotein reference levels during the first year of life

El propósito de este estudio fue determinar la variación de los niveles séricos de alfa fetoproteína (AFP), durante el primer año de vida, utilizando un ensayo inmunorradiométrico. Se realizó la estadística descriptiva en cada período estudiado. Se determinó el tipo de correlación existente entre la AFP sérica y el tiempo. Durante el primer mes de vida se observó una correlación lineal: r = - 0,957; mientras que entre el 2º y 12º mes los datos se ajustaron a una potencial de la forma y = axb : r = 0,989. Los niveles promedios de AFP al primer año de vida fueron similares a los del adulto normal, no obstante un 10 por ciento de los niños estudiados presentó valores más eleva