Sodium in biology mEq/liter (135 - 145 mmol/L). A serum sodium level of less than 135 mEq/L qualifies as hyponatremia, which is considered severe when the serum sodium level is below 125 mEq/L. The renin–angiotensin system and the atrial natriuretic peptide indirectly regulate the amount of signal transduction in the human central nervous system, which depends on sodium ion motion across the nerve cell membrane, in all nerves. Sodium is thus important in neuron function and osmoregulation between cells and the extracellular fluid; the distribution of sodium ions are mediated in all animals by sodium–potassium pumps, which are active transporter solute pumps, pumping
Serum (blood) form of immunotherapy. Blood serum and plasma are some of the largest sources of biomarkers, whether for diagnostics or therapeutics. Its vast dynamic range, further complicated by the presence of lipids, salts, and post-translational modifications, as well multiple mechanisms of degradation, presents challenges in analytical reproducibility, sensitivity, resolution, and potential efficacy. For analysis of biomarkers in blood serum samples, it is possible to do a pre-separation by free-flow electrophoresis that usually consists of a depletion of serum albumin protein. This method enables greater penetration of the proteome via separation of a wide variety of charged or chargeable analytes, ranging from