What is the source of free radicals causing hemolysis in stored blood?

The quality of stored blood can be deteriorated by hemolysis caused by free radicals. The purpose of this study was to elucidate whether neutrophile leukocytes are the source of free radicals in stored blood as in hemodialyzed patients. Resuspensions with low (LL) or high (HL) leukocyte concentrations were prepared from samples of twenty healthy volunteers. The samples were incubated for 10 days at 4 degrees C and then for one day at 37 degrees C. Markers of hemolysis and free radical metabolism were examined before and after incubation in LL and HL samples. In spite of the difference of leukocytes counts in LL and HL resuspensions (p<0.0001), the pre-incubation values of all laboratory parameters were practically identical. In post-storage samples, superoxide dismutase and glutathione peroxidase activities did not differ in either group. Reduced glutathione in erythrocytes and extracellular antioxidant capacity were insignificantly lower in HL resuspensions, but the increase of malondialdehyde was much more pronounced in the HL samples (p<0.0001). The degree of hemolysis, expressed as the extracellular increase of potassium (p<0.001), hemoglobin (p<0.05) and lactate dehydrogenase (p<0.05), was higher in the HL samples. Our results support the hypothesis that leukocytes participate in free radical production in stored blood.

Influence of antioxidants on the quality of stored blood.

BACKGROUND AND OBJECTIVES: Blood is exposed to oxidation stress and therefore has a high antioxidant capacity (AOC). With the many factors increasing the demands on the AOC, there may be damage to erythrocytes by free radicals. This study was to investigate evidence of erythrocyte damage in stored donor blood and to affect this by premedication of blood donors. MATERIALS AND METHODS: Blood samples of 15 healthy donors were collected in CPDA-1 solution and analyzed immediately, and then again after 10 days of incubation at 4 degrees C and 1 day of incubation at 37 degrees C. Prior to incubation, the following parameters were evaluated: Na+, K+, malondialdehyde (MDA), hemoglobin (Hb), AOC in the supernatant, superoxide dismutase (SOD) in erythrocytes, and glutathione peroxidase (GSHPx) in whole blood. Blood donors of group 1 were not given any drugs or vitamins before blood sampling. The same blood donors were then supplemented with the following daily doses of antioxidants for 10 days before the next blood sampling: 36 mg of beta-carotene, 300 mg of vitamin E, 200 mg of vitamin C, and 40 mg of selenium. RESULTS: The blood from donors of group 2 had a significantly smaller increase in MDA, K+, and Hb, and a smaller decrease in Na+ and AOC in the supernatant compared with that of group 1, while the activity of SOD and GSHPx did not change during blood storage. CONCLUSIONS: These results suggest that antioxidants given to blood donors can improve red cell storage parameters by reducing cell damage caused by free radicals.

[The central registry of bone marrow donors and the program for bone marrow transplantation from unrelated donors--20 months' experience]. / Centrální registr dárcu kostní drene a program nepríbuzenských transplantací kostní drene--dvacetimesícní zkusenosti.

The authors describe their 20 months' experience with the establishment of a bone marrow register in the Czech Republic and its practical association with the programme of bone marrow transplantations from non-related subjects. During the 20 months of activity 5455 voluntary bone marrow donors were examined and at present more than 500 new voluntary donors are examined every month. For 21 patients a HLA identical unrelated donor is sought. For four patients a HLA compatible donor was found. The first bone marrow transplantation from a unrelated donor was performed and another patient is prepared for transplantation within the next few days. The authors discuss professional, organizational, moral and ethical problems associated with the elaboration of this medical programme.

[Hepatitis C antibodies in health personnel]. / Protilátky proti viru hepatitidy C u zdravotníku.

Using the second generation test, the authors examined 320 health professionals of the Faculty Hospital in Plzen and dialyzation centres in Karlovy Vary and Sokolov for the presence of antibodies against the hepatitis C virus. Antibodies were detected in 7 of them (2.2%). Serum positivity was confirmed only in paramedical workers, the highest herd immunity was recorded in workers in the dialyzation centre in Plzen. The authors evaluate the prevalence of antibodies in relation to age and period of practice in the health services.

[Hepatitis C virus antibodies in persons on dialysis]. / Protilátky proti viru Hepatitidy C u dialyzovaných osob.

Using the ELISA method (generation II), the authors made a single examination of 172 dialyzed patients for the presence of antibodies against the virus of hepatitis C (VHC). Antibodies were detected in 82 subjects, i. e. 47.7%. The prevalence of antibodies in the examined subjects increased with the number of dialyses, no relationship was found with the number of transfusions. Of 104 subjects where during inclusion into the dialyzation transplantation programme a rise of ALT occurred 69, i. e. 66.3%, had antibodies. Antibodies were detected in 17 of 44 subjects (38.6%) to whom so far blood was not administered. A decisive place in the prevention of VHC transmission in dialyzed subjects is held by non-specific preventive measures, transfusions are most probably not the decisive vehicle.