Can Changes in the Plasma Sodium Concentration Be Predicted Based on the Mass Balance of Sodium, Potassium, and Water in the Face of Osmotically Inactive Sodium Storage?

Alterations in the plasma sodium concentration ([Na+]p) is predicted based on changes in the mass balance of Na+, K+, and H2O. However, it is well appreciated that Na+ retention results in both osmotically active and osmotically inactive Na+ storage and that only osmotically active Na+ contributes to the modulation of the [Na+]p. Subject of Review: Recent clinical studies suggested that prediction of changes in the [Na+]p based on the mass balance of Na+, K+, and H2O is inaccurate since the osmotically inactive Na+ storage pool is dynamically regulated.

Is the Osmolal Concentration of Ethanol Greater Than Its Molar Concentration?

Recent data suggested that the osmolal gap attributed to ethanol as determined by the difference between serum osmolality and serum osmolarity is greater than its molar concentration. The increased osmotic activity of ethanol is thought to be due to its binding to water molecules. This study is conducted to determine the true osmotic contribution of ethanol to serum osmolality.

A Highly Stretchy, Transparent Elastomer with the Capability to Automatically Self-Heal Underwater.

Polymer materials that are able to self-heal in humid conditions or even in water are highly desirable for their industrial applications. However, the development of underwater self-healing polymer materials is very challenging since water molecules can readily disturb traditional noncovalent bonds, such as saturate the hydrogen bonds, coordinate with the metal cation, as well as solvate the ions. Here, a new type of dipole-dipole interactions is employed as the driving force, combining with highly polar and hydrophobic fluorinated polymers, to successfully demonstrate an underwater self-healing elastomer.

Treatment of Cirrhosis-Associated Hyponatremia with Midodrine and Octreotide.

Background: Hyponatremia in the setting of cirrhosis is a common electrolyte disorder with few therapeutic options. The free water retention is due to non-osmotic vasopressin secretion resulting from the cirrhosis-associated splanchnic vasodilatation. Therefore, vasoconstrictive therapy may correct this electrolyte abnormality.

Osmotically inactive sodium and potassium storage: lessons learned from the Edelman and Boling data.

Because changes in the plasma water sodium concentration ([Na(+)]pw) are clinically due to changes in the mass balance of Na(+), K(+), and H2O, the analysis and treatment of the dysnatremias are dependent on the validity of the Edelman equation in defining the quantitative interrelationship between the [Na(+)]pw and the total exchangeable sodium (Nae), total exchangeable potassium (Ke), and total body water (TBW) (Edelman IS, Leibman J, O'Meara MP, Birkenfeld LW. J Clin Invest 37: 1236-1256, 1958): [Na(+)]pw = 1.11(Nae + Ke)/TBW - 25.