Hyper-osmolar

In mammals, the increased uptake of the osmolyte myo-inositol in response to hyperosmolarity has been described in renal medulla cells, lens epithelia, astrocytes, endothelial cells, and Kupffer cells (Paredes et al., 1992 Nakanishi et al., 1988 Warskulat et al., 1997 Wiese et al., 1996 Zhou et al., 1994). The hyper-osmolarity-induced myo-inositol accumulation inside these cells is the result of both an increase in the Vmax of the SMIT and the increased expression of its gene (Kwon et al., 1992 Nakanishi et al., 1989). Conversely, hypo-osmotic exposure... 

Four cases of acute renal insufficiency have been described in men aged 20-42 years who received mannitol 1172 (sd 439) g over 58 (sd 28) hours (7). The onset of acute renal insufficiency was detected 48 (sd 22) hours after the start of infusion. All the patients had dilutional hyponatremia (average 120 mmol/1) and serum hyper-osmolarity (osmolar gap 70 mosm/kg water). In the three anuric cases, in which hemodialysis was performed, there was immediate recovery of diuresis. This emphasizes the risk of renal insufficiency with mannitol and stresses the importance of early hemodialysis. Mannitol is dialysable and once its suppressive effect on renal perfusion is eliminated functional recovery is prompt. 

Hyper-osmolar A fluid is a higher concentration of particles of solute than water. Osmolality greater than 295 mOsm/dg. 

Hypertonic The concentration is more than the concentration of intracellular fluid (hyper-osmolar range greater than 340 mOsm/L). Moves fluid from inside cells into extracellular space. 

Fluids and electrolytes are stored in two compartments intracellular (inside the cell) and extracellular (outside the cell). The amount of electrolytes in fluid is called a concentration. There are three types of fluid concentrations iso-osmolar (same concentration), hypo-osmolar (low concentration), and h) er-osmolar (high concentration). These concentrations are used to describe IV solutions as isotonic (iso-osmolar), hypotonic (hypo-osmolar), and hypertonic (hyper-osmolar). 

With the aid of the three methods described in Sect. 18.5.4 it can be calculated whether or not a pharmaceutical preparation is iso-osmotic. Hypo-osmolarity can usually be avoided as it can be compensated by the addition of excipients in calculated quantities. Hyper-osmolarity may be inevitable due to dosage reasons, for example when a high dose of an active substance has to be administered in a small volume. The extent to which hyper-osmolarity is tolerated will depend on the route of administration and administration site. The tolerance for parenteral administration, for example, increases in the order subcutaneous < intramuscular < intravenously. This has to do with the fact that of these three routes, the intravenously administered dose spreads most rapidly, and thus dilutes most rapidly in the body and the subcutaneously administered dose most slowly. For the same reason, the tolerance is greater when the solution is injected into a large blood vessel than in a small blood vessel. The tolerance is also determined by the volume infused. In Sects. 

Normal semm has an osmolality of between 275 and 295 mOsm/dg. Less than 275 mOsm/dg is hypo-osmolar and greater than 295 mOsm/dg is hyper-... 

If two solutions contain the same number of particles they may be said to be iso-osmotic, or simply isosmotic, with respect to each other. If one solution exhibits a greater osmolarity than another solution it is hyperosmotic with respect to the less concentrated solution. If one solution has a lower osmolarity than another solution then it is hypo-osmotic or hyposmotic, with respect to the more concentrated solution. Iso-, hyper- and hypo-osmolarity should always be stated with respect to another solution. 

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