RESUMEN
The association of mortality with early humoral response to SARS-CoV-2 infection within the first few days after onset of symptoms (DAOS) has not been thoroughly investigated partly due to a lack of sufficiently sensitive antibody testing methods. Here we report two sensitive and automated testing-on-a-probe (TOP) biosensor assays for SARS-CoV-2 viral specific total antibodies (TAb) and surrogate neutralizing antibodies (SNAb), which are suitable for clinical use. The TOP assays employ an RBD-coated quartz probe using a Cy5-Streptavidin-polysacharide conjugate to improved sensitivity and minimize interference. Disposable cartridge containing pre-dispensed reagents requires no liquid manipulation or fluidics during testing. The TOP-TAb assay exhibited higher sensitivity in the 0-7 DAOS window than a widely used FDA-EUA assay. The rapid (18 min) and automated TOP-SNAb correlated well with two well-established SARS-CoV-2 virus neutralization tests. The clinical utility of the TOP assays was demonstrated by evaluating early antibody responses in 120 SARS-CoV-2 RT-PCR positive adult hospitalized patients. Higher baseline TAb and SNAb positivity rates and more robust antibody responses were seen in patients who survived COVID-19 than those who died in the hospital. Survival analysis using the Cox Proportional Hazards Model showed that patients who were TAb and SNAb negative at initial hospital presentation were at a higher risk of in-hospital mortality. Furthermore, TAb and SNAb levels at presentation were inversely associated with SARS-CoV-2 viral load based on concurrent RT-PCR testing. Overall, the sensitive and automated TAb and SNAb assays allow detection of early SARS-CoV-2 antibodies which associate with mortality.
RESUMEN
The arterial supply of the lower end of the human femur in 100 specimens, ranging in age from the newborn to 87 years, was studied by the perfusion method. Its blood supply is derived from the medial and lateral superior genicular arteries, the descending genicular artery and the middle genicular artery. A complete extracapsular anastomotic ring, surrounding the supracondylar portion of the lower end of the femur, is formed by the medial and lateral superior genicular arteries and the descending genicular artery in 55?4.97%. Its incomplete anterior part is linked by the periosteal arterial network in 45?4.97%. The vessels at the metaphyseal side of the growth plate end in a brush-like pattern, intimately connected to the hypertrophic layer of cells of the growth plate, each vessel turning back in a sharp loop. The anterior and posterior metaphyseal arteries which arise from the extracapsular anastomotic ring and network supply the supracondylar area. The medial and lateral epiphyseal arteries, arising respectively from the descending genicular artery and both superior genicular arteries, supply the medial part of the medial condyle and the lateral part of the lateral condyle. The anterior and intercondylar epiphyseal arteries, arising respectively from the periosteal network and the mildle genicular artery, supply the intercondylar area. The epiphyseal arteries which anastomose with each other in the ossific area of the epiphysis form the precapillaries and capillary network. The anastomotic branches between the epiphyseal arteries, ranging from 25 to 100 microns in diameter, form the arterial plexus in the epiphysis. With the closure of the epiphyseal plate, a free anastomosis is established between the metaphyseal and the epiphyseal vessels. The clinical significance of the topographical characteristics, the course and the distribution of the arterial supply to the lower end of the femur were discussed.
RESUMEN
The arterial supply of the human scaphoid was studied in 166 specimens ofhands from fresh cadavers of different ages ranging from 6(1/2)months of gestationto 89 years old by injection and clearing techniques.The scaphoid receives its bloodsupply mainly from the radial artery and its superficial palmar branch.There aretwo groups of nutrient arteries,the dorsal and the volar nutrient arteries,enteringthe scaphoid.The dorsal group of arteries which supplies the proximal 70% to 80%of the scaphoid is the main contributor to the intraosseous blood supply.The volargroup of arteries only supplies the distal 20% to 30% of the bone.An explanationfor the cause of scaphoid necrosis following fracture on the basis of the vascularitywas proposed.
