A rapid and accurate single-drop modification of the acid-elution technique for detecting fetomaternal hemorrhage.

A single-drop modification of the acid-elution technique (Kleihauer-Betke) for quantitating fetomaternal hemorrhage is described. It obviates the need for the tedious and time-consuming manual counting of background adult cells. Rather, this is achieved by automated red-blood cell counting of the initial specimen and delivery of a standard volume (1 microliter) of a standard dilution (1:1,000) in the form of a droplet to a microscope slide. The droplet is left to dry undisturbed at room temperature and then stained. The fetal cells are manually counted while the total number of cells is calculated from the initial red-blood cell count, standard volume, and standard dilution. Determinations on 4 different concentrations of fetal/adult red cell mixtures are performed. Results indicate improved accuracy and precision relative to the standard technique in significantly less time for volumes of fetomaternal hemorrhage requiring more than the standard dose of Rho(D)-immune globulin.

Comparison of quantitative acid-elution technique and flow cytometry for detecting fetomaternal hemorrhage.

A study of the Kleihauer-Betke acid-elution technique for quantitating fetomaternal hemorrhage was performed to assess intra- and inter-technologist accuracy and precision as well as to delineate the statistically valid domain of the test as usually performed. The results were then compared to a parallel study quantitating fetomaternal hemorrhage by flow cytometry. Additionally, a statistical model for estimating efficacy of treatment with Rh immune globulin in the prevention of pregnancy-associated Rh(D) isoimmunization was developed. The results indicate that the acid-elution technique can be performed in a reproducible manner with acceptable accuracy and precision with whole blood fetomaternal hemorrhages 25 ml and higher if a background correction for false positive identification of fetal cells is included. Flow cytometric determination reveals significantly increased accuracy in comparison to the corresponding Kleihauer-Betke results.

Comparison of monoclonal antisera with conventional antisera for Lewis blood group antigen determination.

Monoclonal blood grouping sera provide a means of overcoming difficulties inherent in the use of conventional polyclonal reagents. Two murine monoclonal anti-Lewis reagents were tested and found to be comparable to conventional reagents for use in red cell phenotyping. These reagents may detect Le(a) antigen on Le(a-b+) red cells with greater sensitivity than previously available polyclonal anti-Lewis reagents.

Detection of IgG anti-Lewis (a) antibodies in cord sera by kinetic Elisa.

Lewis blood group antibodies rarely, if ever, cause hemolytic disease of the newborn. This observation has been attributed to the absence both of Lewis antigens on fetal cells and of maternal IgG Lewis antibody. In the present study, sera from 13 mother-infant pairs were tested for the presence of anti-Lewis (a) by hemagglutination and by a sensitive and specific kinetic enzyme-linked immunosorbent assay. By routine hemagglutination methods, anti-Lea was present in all maternal samples but absent in all cord samples. By kinetic enzyme-linked immunosorbent assay, IgG anti-Lea was present in 13 of 13 maternal samples and in 12 of 13 cord samples. These results indicate that IgG anti-Lea antibodies are common and do cross the placenta. This suggests that they do not cause hemolytic disease of the newborn because of the low levels of Lewis antigens on fetal red cells.

Neutralization of Lewis blood group antibodies by synthetic immunoadsorbents.

The neutralization of antibodies to the Lewis blood group systems is important in confirming the presence of these antibodies and in investigating complex alloantibody problems. An improved method for neutralizing Lewis antibodies is described. Insoluble immunoadsorbents containing synthetic Lewis antigens are used to physically remove the antibody from serum. Thirty-five sera containing Lewis antibodies were neutralized completely using this technic; 23 non-Lewis alloantibodies were not inhibited. In contrast with current methods, this technic does not dilute the patient serum and results in an affinity purified serum sample.

A new technique in quantitative immunohematology: solid-phase kinetic enzyme-linked immunosorbent assay.

A solid-phase kinetic enzyme-linked immunosorbent assay has been developed to measure binding of antibodies to purified or synthetic blood group antigens and tested in the Lewis blood group system. Chemically synthesized Lewis a antigen is used as the target for the binding of serum antibody in this sandwich-type assay. Kinetic, rather than endpoint, determinations are used to calculate the amount of specific antibody. Data are presented showing the assay to be quantitative, sensitive, and specific. It can separately quantitate the amount of IgG or IgM anti-Lewis a present in patient sera. The assay uses commercially available reagents and is semiautomated. Thus, it will be useful for studies in quantitative immunohematology as other blood group antigens become available in purified form.

The serology of Sda effects of transfusion and pregnancy.

Pre- and posttransfusion antibody titers were performed on 6 patients with anti-Sda transfused with incompatible blood. In 3 of these patients a significant rise in IgG antibody titer was found. The data suggest that in occasional patients the Sda antigen does evoke a secondary immune response. We evaluated 245 pregnant women for the presence of Sda and found that 30% were Sd(a-). This incidence was significantly higher than that found in normal blood donors (4%), but was lower than that described in previous reports. We found that 22% of pregnant women in their first trimester were Sd(a-) whereas at term 36% were Sd(a-). These significantly different incidences of antigen positivity suggest decreased antigen expression with progressing pregnancy, as seen in the Lewis system. No difference was found in the incidence of anti-Sda between pregnant women, either during their first trimester or at term, and normal donors.

Linked Aryl Aryloxypropanolamines as a new class of lipid catabolis agents.

The synthesis of a series of stilbene, biaryl, tolane, diaryl ether, sulfide, sulfoxide, and sulfone oxypropanolamines as potential antiobesity agents is described. These compounds were evaluated in a mouse lipid catabolism screen, and the more active members of the series, 4, 57, and 58, were further investigated in rats and dogs. 1-(2,6-Ditert-butyl-4-trans-styrylphenoxy)-3-isopropylamino-2-propanol (4) possessed considerable lipid catabolic activity in mice and caused a significant reduction in the body weight of rats after 5 weeks and of dogs after 6 weeks. Only hematological irregularities in a chronic toxicity study precluded further development of this compound as an alternative antiobesity treatment.