Are There Differences in the Anthropometric, Hemodynamic, Hematologic, and Biochemical Profiles between Late- and Early-Onset Preeclampsia?

Figure 1

Typical curve of osmotic stability of erythrocytes. The lower plateau defines the A_min variable, which represents the amount of basal hemolysis present in the blood sample of each study volunteer. The decrease in the tonicity of the medium is associated with increased lysis of erythrocytes and release of hemoglobin in the solution, resulting in increased absorbance at 540 nm with formation of a curve of sigmoidal nature whose upper plateau defines the A_max variable, which represents the occurrence of 100% hemolysis. The curve passes through an intermediate point defining the H₅₀ variable, which represents the concentration of NaCl required to promote 50% hemolysis. The saline concentration at the starting point of the curve defines the H₀ variable, which is the saline concentration required to initiate in vitro hemolysis and which can be calculated by the formula H₀ = H₅₀ + 4 dX/2. The saline concentration at the point where the in vitro lysis reaches its maximum plateau defines the H₁₀₀ variable, which represents the saline concentration necessary to promote the total lysis of the red blood cells, being calculated by the formula H₁₀₀ = H₅₀ − 4 dX/2. The dX variable represents a quarter of the variation in saline concentration required to promote 100% hemolysis.