Chronic Severe Hyponatremia and Cardiopulmonary Bypass: Avoiding Osmotic Demyelination Syndrome

Serum sodium concentration affects every cell in the body with respect to cellular tonicity. Hyponatremia is the most frequent electrolyte abnormality encountered, occurring at clinical admission in 22% of elderly patients. Any rapid correction of chronic severe hyponatremia can result in rapid cellular shrinking due to loss of intracellular free water. This is commonly associated with paralysis and severe brain damage due to osmotic demyelination syndrome (ODS). ODS occurs because the body has the ability to compensate for cellular fluid shifts due to chronic hyponatremia (by a decrease in brain concentration of several ions, amino acids, and organic osmolytes). Thus, the neurons are often at a functional state of fluid balance despite the sodium imbalance. The initiation of cardiopulmonary bypass (CPB) can introduce between 1 and 2 L of priming solution containing a normal sodium concentration creating a rapid rise in sodium concentration within the extracellular fluid. This abrupt change establishes a situation where intracellular free water can be lost resulting in cellular shrinking and ODS. In presenting this case study, we hope to add to the current literature with a specific isotonic approach to treating the chronically severe hyponatremic patient pre-CPB, during CPB, and post-CPB

Fat Affects Predator-Avoidance Behavior in Gray Catbirds (\u3ci\u3eDumetella carolinensis\u3c/i\u3e) During Migratory Stopover

During migration, birds may store large quantities of fat to fuel long-distance flight. Because mass affects flight performance, fat migrants should behave with greater caution toward aerial predators than lean migrants. We tested a prediction of this hypothesis, namely, that fat birds will remain motionless longer than lean birds after a simulated encounter with a raptor. We captured Gray Catbirds (Dumetella carolinensis) during fall migration, classified their subcutaneous fat, exposed them to a model hawk, and then recorded the time until their first perch change. To determine whether the birds treated the simulated predator as a threat, we also tested them with a hexagon-shaped model and with no model. The birds remained motionless longer with the hawk model than either of the two other treatments. Fat birds remained motionless longer than lean birds when exposed to the hawk model, but we detected no difference with the other two treatments. These results provide evidence that fat affects the predator-avoidance behavior of Gray Catbirds during migratory stopover. That a difference between fat and lean groups was only apparent with the hawk model treatment suggests that the result is attributable to differences in the flight performance of the two groups rather than simply a difference in motivation to begin foraging. We suggest that fat should influence the behavior of a wide variety of migrant birds, particularly those species that typically carry greater fat reserves or that forage in more exposed situations than the Gray Catbirds we tested

Antigen Processing of the Heptavalent Pneumococcal Conjugate Vaccine Carrier Protein CRM(197) Differs Depending on the Serotype of the Attached Polysaccharide

The pneumococcal (Pn) conjugate vaccine includes seven different polysaccharides (PS) conjugated to CRM(197). Utilizing antigen-processing cells and a CRM(197)-specific mouse T-cell hybridoma, we found that the serotype of conjugated PnPS dramatically affected antigen processing of CRM(197). Unconjugated CRM(197) and serotype conjugates 14 and 18C were processed more efficiently

Metropolitan seminars in art : Great periods in painting /

Pronunciation guide, 2 p. in pocket of each portfolio.Review questions, 1 p. in pocket of each portfolio.Mode of access: Internet