Seroconversion and Abundance of IgG Antibodies against S1-RBD of SARS-CoV-2 and Neutralizing Activity in the Chilean Population.

COVID-19 is a pandemic caused by SARS-CoV-2. In Chile, half a million people have been infected and more than 16,000 have died from COVID-19. As part of the clinical trial NCT04384588, we quantified IgG against S1-RBD of SARS-CoV-2 (anti-RBD) in recovered people in Santiago and evaluated their suitability as COVID-19 convalescent plasma donors. ELISA and a luminescent SARS-CoV-2 pseudotype were used for IgG and neutralizing antibody quantification. 72.9% of the convalescent population (468 of 639) showed seroconversion (5-55 µg/mL anti-RBD IgG) and were suitable candidates for plasma donation. Analysis by gender, age, and days after symptom offset did not show significant differences. Neutralizing activity correlated with an increased concentration of anti-RBD IgG (p < 0.0001) and showed a high variability between donors. We confirmed that the majority of the Chilean patients have developed anti-SARS-CoV-2 antibodies. The quantification of anti-RBD IgG in convalescent plasma donors is necessary to increase the detection of neutralizing antibodies.

[Clinical correlation between the premortem study and autopsy]. / Correlación clínica entre el estudio pre mortem y la autopsia.

BACKGROUND: Lately, autopsies are performed less frequently in hospitals, despite their importance as a diagnostic tool. AIM: To study the concordance between clinical diagnosis and postmortem study in patients that died in a teaching hospital. MATERIAL AND METHODS: Autopsy findings in 57 patients (aged 16 to 85 years old, 28 female) that died at a University hospital were analyzed. Clinical diagnoses were compared with those of the postmortem examination and the degree of concordance between both diagnoses was calculated. RESULTS: Seven major omissions (12.3%), whose knowledge could have changed the clinical course of patients, were detected. These omissions occurred in patients with complex diseases or due to limitations of diagnostic procedures. Also, seven omissions, found in severely ill patients, whose knowledge would not change the patient's evolution, were also detected. CONCLUSIONS: Autopsy still is a valuable tool to assess the quality of care for patients that die during their hospitalization.

Factors determining peripheral vein tolerance to amino acid infusions.

The tolerance of peripheral veins to intravenous infusions was evaluated. Of 83 infusions studied, 67 contained amino acids. Phlebitis occurred more commonly with the use of solutions that contained the amino acids. The important factors in the production of phlebitis by amino acid solutions were osmolarity, and the amount of potassium infused per day. Phlebitis was universal when osmolarity exceeded 600 mOsm. Other factors that promoted phlebitis were the presence of antibiotics and the size of the vein.

An analysis of the components of the pulmonary shunt equation: significance of the alveolar-arterial oxygen gradient, arterio-venous oxygen content difference, and mixed venous oxygen pressure.

Pulmonary shunt calculated by the Berggren method is commonly used as an indicator of pulmonary function. Although there is usually a good correlation between the shunt and the A-aDO2, other physiologic parameters involved in the shunt equation may significantly alter pulmonary function. The purpose of this study is to show the contribution of the PVO2 and a--v diff to the shunt equation. Data from eight selected patients with A--aDo2 values ranging from 300 to 395 torr and calculated shunts ranging from 6 to 35% were selected for this purpose. In patients with significant changes in PVO2 and a--v diff, the A--aDO2 is more reliable as an indicator of pulmonary function than is the calculated shunt.