ABSTRACT
BackgroundWe aim to investigate the profile of acute antibody response in COVID-19 patients, and provide proposals for the usage of antibody test in clinical practice. MethodsA multi-center cross-section study (285 patients) and a single-center follow-up study (63 patients) were performed to investigate the feature of acute antibody response to SARS-CoV-2. A cohort of 52 COVID-19 suspects and 64 close contacts were enrolled to evaluate the potentiality of the antibody test. ResultsThe positive rate for IgG reached 100% around 20 days after symptoms onset. The median day of seroconversion for both lgG and IgM was 13 days after symptoms onset. Seroconversion of IgM occurred at the same time, or earlier, or later than that of IgG. IgG levels in 100% patients (19/19) entered a platform within 6 days after seroconversion. The criteria of IgG seroconversion and > 4-fold increase in the IgG titers in sequential samples together diagnosed 82.9% (34/41) of the patients. Antibody test aided to confirm 4 patients with COVID-19 from 52 suspects who failed to be confirmed by RT-PCR and 7 patients from 148 close contacts with negative RT-PCR. ConclusionIgM and IgG should be detected simultaneously at the early phase of infection. The serological diagnosis criterion of seroconversion or the >; 4-fold increase in the IgG titer is suitable for a majority of COVID-19 patients. Serologic test is helpful for the diagnosis of SARS-CoV-2 infection in suspects and close contacts.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the influences of different dosage ferrous sulfate supplements on bone marrow hemopoiesis in rats.</p><p><b>METHODS</b>Female weaning Wistar rats were fed with an iron deficient diet (< 10 mg/kg diet) until the level of hemoglobin of rats was lower than 100 g/L. Rats (n = 50) were randomly divided into five groups according to the levels of hemoglobin and body weight, iron deficiency control (ID), daily low iron diet supplement (LDs), daily high iron diet supplement (HDs), weekly low iron supplement (LWs), and weekly high iron supplement (HWs).</p><p><b>RESULTS</b>After 12 weeks, bone marrow stainable iron was seldom in ID group, and ample in supplement groups. The proportions of iron staining of bone marrow smear in supplement groups were more than 30%. Bone marrow cells in all rats were hyperplastic or active hyperplastic.</p><p><b>CONCLUSIONS</b>Daily high iron supplement or once weekly high iron supplement were safe to bone marrow hemopoiesis in rats.</p>
