The absorption of anti-N with type M blood must be done very cautiously to avoid removal all of the anti-N activity. This has been known since the MN types were first reported by Landsteiner and Levine ( 2 ) . It explains the weakness of rabbit anti-N reagents, which must always be absorbed since the native anti-N rabbit serum invariably agglutinates human type M red cells. The titer against type N bloods may be very high before absorption with type M red cells, but when such absorption has been camed to the point where the serum no longer agglutinates a fresh sample of the absorbing cells, the titer against type N cells has become quite low. Further absorption with type M cells removes all antibody.
Levine, Ottensooser, Celano and Pollitzer ( 3 )showed that anti-N obtained from the seeds of Vicea graminea also was easily absorbed by human type M red cells, leaving the reagent inactive against N cells. [l] demonstrated that human anti-N also behaved in the same fashion, even when absorbed with the red cells of the anti-N donor himself.
Hirsch, Moores, Sanger and RaceWe have confirmed all these observations, but were fortunate in finding a type M blood that failed to absorb any anti-N, which indicates that the tendency of type M red cells to absorb anti-N is not necessarily caused by their content of M factor. The data to be presented suggest that ordinary M genes produce a small amount of N factor,
The authors studied the distribution of alanine aminotransferase (ALT) levels in 10,034 volunteer blood donors. The mean +/- SD ALT value was 21.4 +/- 19.3 IU/liter; 549 (5.5%) of the donors had a ALT value greater that 45 IU; 2.5 per cent had ALT values greater than 60 IU. In general, ALT levels were higher in males than in females, and were age related; peak values occurred in the third decade of life for males and between 50-60 years of age in females. ALT values greater than 45 IU were found significantly more often in males, in donors of both sexes 30-40 years of age, in married donors, in non-Caucasians, and in those whose education level was no higher than high school. Follow-up samples in donors with an initial ALT greater than 45 IU, revealed that 67% continued to have ALT values above 45 IU 2-8 weeks following initial sampling, and 40% had an ALT greater than 45 IU when tested again six months after entry into the study. ALT values greater than 60 IU were associated with a significantly increased prevalence of antibody of hepatitis B surface antigen (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc) occurring together. No statistically significant association was found between transaminase activity and the prevalence of anti-HBs or anti-HBc alone, or with hepatitis A antibody. These findings demonstrate that there are defined sociodemographic and serologic features of donors with elevated ALT values.
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