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Incidence of red cell antibodies after multiple blood transfusion

A retrospective study was performed to estimate the frequency of alloimmunization against red cell (RBC) antigens in a multiply transfused group. Patients (n = 186) were studied who had received at least six blood transfusions during a period of at least 3 months. Some 6944 units of blood were transfused. One hundred forty patients had hematologic disorders. The patients' sera were investigated every 3 months with indirect antiglobulin tests and enzyme-treated RBCs. Twenty-two patients (11.8%) made 33 antibodies. Seven patients made more than one antibody. Eight of the 22 patients (36.4%) made their first antibody before or at the 10th transfusion. The risk of immunization increased with the number of transfusions. Influence of gender and age was not demonstrable. Nor was a relationship demonstrated between blood transfusion reactions and RBC antibody formation; no delayed hemolytic transfusion reactions occurred. Anti-E was demonstrated in 12 patients and anti-K in 15. When the gene frequencies were taken into account, it appeared that anti-E was made by 11.5 percent of E-negative patients, most of whom were immunized after an estimated three transfusions with E-positive blood. Anti-K was made by 8.7 percent of the K-negative patients, after an estimated 2.1 units of K-positive blood. It might be desirable to match red cell units for the E and K antigens in patients at relatively high risk. These are primarily patients who have already formed an antibody and are going to receive many transfusions and women of childbearing age who are to receive more than 4 units of blood.     

No evidence of frequent human immunodeficiency virus type 1 infection in seronegative at-risk individuals

The possible existence of human immunodeficiency virus type 1 (HIV-1) infection in asymptomatic seronegative at-risk individuals was investigated in a prospective study of 55 seronegative high-risk individuals (42 homosexual men and 13 heterosexual individuals) and 32 seronegative hemophiliacs treated with factor VIII or IX concentrates before viral inactivation by heat treatment and systematic screening of blood donations. Tests used include the polymerase chain reaction assay with three primer pairs (one in the gag region and two in the pol region) and tests for serum p24 antigen, anti-nef serology (Western blot), and five biologic markers frequently altered by HIV infection (CD4 lymphocyte count, serum beta 2-microglobulin and neopterin concentration, and serum IgG and IgA concentration). Although 91 of 92 HIV-1-seropositive persons were positive in testing with at least one primer pair, no positive result was observed in seronegative at-risk individuals or in 117 seronegative low-risk controls. No nef antibody was found in seronegative at-risk individuals or seronegative controls, but 44 (47%) of 92 HIV-1-seropositive persons had nef antibodies. These findings do not support the existence of frequent HIV-1 infection in seronegative at-risk individuals.     

Ankle: surface coil MR imaging at 1.5 T

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.     

1H nuclear magnetic resonance and clinical studies of interaction of calcium antagonists and hypoglycemic sulfonylureas

The hypoglycemic effect of gliclazide is mainly due to its action on ATP stimulated K+ channels, but the calcium ionophoretic effect of this drug may also be involved in its physiological properties. Using 1H NMR we demonstrated the antiionophoretic effect of nifedipine and diltiazem. We attempted to verify whether this in vitro interaction also occurs in vivo. A clinical trial, was performed on patients treated concomitantly with gliclazide and nifedipine or diltiazem. Results showed that no in vivo interaction occurred. The discrepancy between in vivo and in vitro results may be explained by a too weak plasma concentration in the case of nifedipine and by a large plasma protein binding in the case of diltiazem.     

Evaluation of pediatric transfusion practice using criteria maps

Pediatric blood transfusion practice in a tertiary-care pediatric hospital was evaluated retrospectively by using the technique of criteria mapping. A total of 630 transfusion episodes involving red cell concentrates, frozen plasma (plasma frozen within 24 hours of collection), platelet concentrates, and albumin were reviewed: 243 (86.2%) were reviewed only by a technical assistant, and 87 (13.8%) required additional physician review. Of these, 138 were red cell concentrate transfusions: 79.7 percent of that group were considered appropriate, 11.6 percent of unknown benefit/risk ratio, 5.8 percent inappropriate, and 2.9 percent impossible to evaluate. Some 246 frozen plasma transfusions were reviewed: 42.3 percent were considered appropriate, 32.5 percent of unknown benefit/risk ratio, 17.5 percent inappropriate, and 7.7 percent impossible to evaluate. A total of 139 platelet concentrate transfusions were reviewed: 64.7 percent were considered appropriate, 16.5 percent of unknown benefit/risk ratio, 10.1 percent inappropriate, and 8.6 percent impossible to evaluate. Some 107 albumin transfusions were reviewed: 90.6 percent were considered appropriate, 1.9 percent inappropriate, and 7.5 percent impossible to evaluate. The criteria maps developed for this study were easy for the technical assistant to use, and areas of appropriate and inappropriate pediatric transfusion practice were clearly identified.