Erythrocyte storage in hypertonic (SAGM) or isotonic (PAGGSM) conservation medium: influence on cell properties.

BACKGROUND AND OBJECTIVES: Prolonged red blood cell (RBC) storage may be associated with increased post-transfusion morbidity and mortality. A contributing factor is RBC storage lesions. We analysed the role of additive conservation solutions, either hypertonic or isotonic, on such cell properties. MATERIALS AND METHODS: After blood donation in citrate-phosphate-dextrose as an anticoagulant, 10 RBC units were stored with saline-adenine-glucose-mannitol (SAGM; 376 mOsm/l) and 10 units with phosphate-adenine-glucose-guanosin-saline-mannitol (PAGGSM; 285 mOsm/l). Measurements were made on days 1 and 42 of storage. RESULTS: The mean cellular volume measured by centrifuged microhaematocrit increased from 87.6 +/- 3.1 fl to 100.7 +/- 4.3 fl in PAGGSM and to 92.2 +/- 2.5 fl in SAGM (P < 0.001) on day 1, after 42 days it was 95.8 +/- 4.0 fl and 93.8 +/- 3.9 fl, respectively. Spontaneous haemolysis and osmotic fragility were lower after storage in PAGGSM. Both additives showed a similar degree of echinocytosis, decreased RBC aggregability and deformability, and increased RBC suspension viscosity after storage. CONCLUSIONS: The isotonic PAGGSM prevented the initial RBC swelling caused by citrate-phosphate-dextrose less than hypertonic SAGM, but reduced the spontaneous haemolysis rate and osmotic fragility after 42 days of storage. All other parameters, such as echinocytosis, decreased RBC deformability and aggregability, and increased blood viscosity was similar for both additive solutions and remained a major problem of blood banking.

Stereoselective trans- and cis-dihydroxylations of 2H-pyranyl and dihydropyridinyl heterocycles synthesized from formal [3 + 3]-cycloaddition reactions of alpha,beta-unsaturated iminium ions with 1,3-dicarbonyl equivalents.

[reaction: see text]We describe here an inherent problem in direct epoxidation of the endocyclic olefin in 2H-pyrans fused to 2-pyrones. Such difficulties led to the development of highly stereoselective trans- and cis-dihydroxylations of these olefinic systems in both 2H-pyrans and dihydropyridines fused to a 2-pyrones or a 2-cyclohexenone. Protocols for the removal of the activated allylic hydroxyl group are also reported.