Glycerol treated human red cells frozen with liquid nitrogen

ABSTRACTS circulatory arrest or profound hypothermia of 7” to 15”C, with and without complete circulatory arrest induced by extracorporeal circulation of moderate flow rates for 30 to 60 min to elucidate further the cause of reported changes in the central nervous system. Neurological changes and morphological studies of brains showing changes in neuroglia and ganglion cells and cerebral edema are described. The authors conclude that, although it was impossible by this study to separate all of the possible factors involved in central nervous system changes wit,h deep hypothermia and circulatory arrest, the absence of significant changes in the blood-brain barrier after rapid cooling and warming alone suggests that these changes may not be related to 1) cerebral hypoxia during the cooling or warming phases alone, 2) gas embolism, 3) aggregation of formed elements due to cold alone during the cooling process, and 4) the effect of cold blood entering the warm brain and warm blood entering the cold brain--etiological mechanisms previously postulated by others. Selective Cerebral Hypothermia: Physiology and Technique. MISCO, J. C. Ann. Surg., 161: 378389, 1965. A safe technique for producing selective brain cooling by a perfusion method is described. Of 15 dogs, 7 survived. The salient features aiding survival are discussed. The use of a direct vasodilator (papaverine) in the perfusate to relieve vasospasm markedly reduced cooling time and represented the most significant technical advance over previously described methods. An acid-base analysis utilizing the SiggaardAndersen curve normogram was performed on 4 dogs, and no significant acidosis was noted during selective brain cooling. A definite arteriovenous lactic acid difference developed at hypothermic temperatures, indicating that the brain may metabolize this substance in preference to glucose at lowered brain temperatures. The reasons for this are discussed. The rate of disappearance of physically dissolved oxygen (PO,) was measured in the brain following ische:mia at different temperatures. The average rate of disappearance at 20°C was 40% of the rate at 37°C. The discrepancy between this finding and the oxygen utilization rate in vitro at the same temperature is discussed. A New Method for Microscopic Assay of Cellular Freezing Process. LOZINA-LOZINSKY, L. K., AND P. E. MOROZ. Tsitologiia, 6: 774-778, 1964. A chamber used in microscopy for observation of freezing and thawing processes is described. The operational features of the chamber include lower-

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and continuous ing of temperatures to -190°C observation of cells frozen to described temperatures following immersion into an aqueous solution or isopentane. Acridine orange was added to cells prior to freezing for subsequent fluorescent mirroscopy. Freezing of the Chromoprotein Phycoerythrin from the Red Alga Porphyridium cruentunt. TSIBO, S. P., AND R. I?. JONES. Arch Biochem., 106: 7%88,1964. Exposure of the chromoprotein phycoerythrin to subzero temperatures resulted in changes in its physical properties. The protein, purified from the unicellular red alga Porphyridium cruentum, was analyzed by means of sedimentation analysis, disc electrophoresis, and absorption and fluorescence spectroscopy. Absorption spectroscopy indicated a general hypochromicity and loss of an absorption maximum, and fluorescence spectroscopy indicated an increased yield following treatment. Sedimentation and electrophoretic analyses of repeatedly frozen-thawed phycoerythrin demonstrated a decrease in the amount of “native” phycoerythrin, and t,he presence or increase of two new additional components. The nature and extent of the alteration seemed to depend, at the least, upon the minimum temperature to which the sample was exposed, and on the rate at which it was rewarmed to room temperature. Glycerol Liquid

Treated Human Red Cells Frozen with Nitrogen. KRIJNEN, H. W., J. J. FR. M. DE WIT, A. C. J. KUIVENHOVEN, J. A. Loos, AND H. K. PRIXS. VOX Sang., 9: 559-572, 1964. A met,hod is described for the preservation of red rrlls in the frozen state. By freezing in liquid nitrogen, it, is possible to obtain, after freezing and thawing, high recoveries of red cells with a low concentration of glycerol as a protective additive. Wit,hout special equipment the removal of glyccrol from the thawed red cells can be carried out by washing with 16% sorbitol in a 0.9% NaCl solution. The viability of t,he processed red cells as shown by their metabolic properties, osmotic and post-transfusion survival is very fragility, satisfactory. Effects of Subzero Temperatures on the Unicellular Red Alga Porphyridium cruentum. LEIBO, S. P., AND R. F. JONES. J. Cell. Comp. Physiol., 69: 295-302, 1963. Injury to intact cells of Porphuridium by exposure to subzero temperatures was assayed by three methods. The amount of phycoerythrin lost from the cells increased with decreasing subzero temperature,