Summary The effect of a low ionic strength environment on the serologic activity of 64 anti‐sera was studied by substituting iso‐osmotic glycine for buffer in the diluent. Some enhancement was achieved with most antibodies, both complete and incomplete, except for antibodies with ABO and Lewis specificity. Red cell sensitization and possibly agglutination of sensitized cells appear to be enhanced in the presence of a low ionic strength milieu. A reduction of ionic strength from 0.26 to about 0.07 results in reducing the antiserum requirement by about one‐half. The most marked enhancement occurred with Rh isoantibodies and the glycine‐antiglobulin technique enhanced significantly the detection of “low grade” Du cells. Enzyme modification and low ionic strength (glycine‐buffer) appear to be equivalent in potentiating antibody activity except that antigens inactivated by enzymes (M) are enhanced by glycine‐buffer and other antigens enhanced by enzymes (Le) are not potentiated by glycine‐buffer. These findings indicate that a low ionic strength diluent is most useful as a supplemental technique and should not displace current techniques until more experience is available. Résumé L'effct d'un milieu de basse force ionique sur l'activité sérologique de 64 antisérums a été étudié en utilisant un tampon iso‐osmotique au glycocolle pour les dilutions. On a observé une augmentation de l'activité de la plupart des anticorps ccmplets et incomplete sauf pour les anticorps de spécificité ABO et Lewis. La sensibilisation des érythrocytes et l'agglutination possible des érythrocytes sensibilisés semble être augmentée en présence de milieu à force ionique basse. Une réduction de la force ionique de 0,26 à 0,07 permet de réduire de moitié la quantité d'anti‐sérum requise. L'augmentation la plus marquée a été obtenue avec les iso‐anticorps anti‐Rhésus et la technique à l'antiglobuline‐glycocolle augmente d'une manière significative la mise en évidence des érythrocytes Du. Les modifications obtenues par les enzymes et par les tampons glycocolles à basse force ionique semblent être équivalentes en ce qui concerne la potentialisation de l'activité des anticorps, sauf pour les antigènes inactivés par les enzymes (M) qui sont augmentés par le tampon glycocolle et les antigènes potentialisés par les enzymes qui ne le sont pas par le tampon glycocolle. Ces faits démontrent qu'un solvant à basse force ionique est surtout utilisable comme une technique complémentaire et qu' il ne doit pas faire écarter les techniques usuelles jusqu'à ce qu'on ait davantage d'expérience à ce sujet. Zusammenfassung Zum Studium des Einflusses eines Milieus mit niederer Ionenstärke auf die serologische Aktivität von 64 Antiseren wurde der Puffer der Aufschwemmungsflüssigkeit durch isoosmotisches Glyzin ersetzt. Mit Ausnahme der ABO‐ und Lewis‐spezifischen Antikürper wurde bei den meisten Antikürpern, sowohl bei kompletten wie auch bei inkompletten, eine Verstärkung der Reaktionen beobachtet. Sowohl die Sensibili‐sierung der Erythrozyten als wahrscheinlich auch ...

For 173 pairs of like-sex adult twins, self-assessment of zygosity was verified by laboratory diagnosis. Seventeen percent of twins who were very likely monozygous (MZ) believed themselves dizygous (DZ), frequently citing two placentas at their delivery as “evidence.” We suggest that twins be asked what leads them to their assessment of their own zygosity. For 93% of Caucasian and 89% of American Black like-sex twins in our sample, DZ twins could be differentiated based on six polymorphic markers retrievable from frozen sera. MZ twins who believe themselves DZ can be considered “environmentally DZ, genetically MZ” twins, and might be used to study genetic and environmental influences on the treatment of twins and on twins' choices of social characteristics.

The coloration of nipple aspirates of breast fluid from 2,343 women were compared with breast fluid concentrations of cholesterol. cholesterol epoxides, lipid peroxides, estrogens, and immunoglobulins. Darker-colored breast fluid had significantly higher mean concentrations of cholesterol, cholesterol epoxides, lipid peroxides, and estrogens than did lighter-colored fluids, whereas no relationship of coloration with immunoglobulin levels was found.

Summary. The red cells of 63 members of 11 families were tested with 125I-labeled anti-Rh0(D). Families with a history of hemolytic disease of the newborn due to fetomaternal Rh incompatibility were selected for study. In such families it was possible to determine the antibody binding to the Rho(D) heterozygous red cells of the children and to compare within each family this value with the antibody bound to the father's Rh0(D)-positive red cells and the mother's Rh0(D)-negative red cells. The fathers in all the families studied could be assigned to two classes on the basis of the quantity of antibody bound to their red cells. One group bound about the same quantity of antibody to their cells as did their children, indicating that they were heterozygous for the Rho(D) antigen. The other bound about twice as much antibody to their cells as did their children, indicating that they were homozygous for the antigen. The Rh genotype of the father in all 11 families could be ascertained by using the children in each family as a reference point. The members of two families showed a poor correspondence between antibody binding and zygosity. In one family an Rh heterozygous child (R1r) took up 85% of the antibody bound to the father's homozygous cells (R'R'), and in the other family an Rh heterozygous child (R1r) took up 20% more antibody than did the cells of her father, which were of the same Rh phenotype (Rh,) and zygosity.

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