Partial reversal of low molecular weight heparin (PK 10169) anti-Xa activity by protamine sulfate: in vitro and in vivo study during cardiac surgery with extracorporeal circulation.

Neutralization of a low molecular weight (LMW) heparin fraction by protamine sulfate was evaluated in vitro and in vivo. Anti-Xa and anti-IIa activities were measured by amidolytic and coagulation methods (activated partial thromboplastin time, APTT). Fifteen patients (4 males and 11 females) underwent surgery with extracorporeal circulation. In vitro, anti-Xa and anti-IIa activities and APTT of unfractionated heparin were neutralized with a protamine/heparin (P/H) gravimetric ratio of 1.6, 1.33 and about 2, respectively. Anti-IIa activity and APTT induced by PK 10169 were completely corrected at a P/H ratio of 1 and 2, respectively, while anti-Xa activity was incompletely neutralized at a ratio of 5. In vivo, in 9 patients who did not receive intravenous protamine sulfate, a good correlation was found between doses of PK 10169 infused, anti-IIa plasma level and blood loss. In 3 patients who were treated prophylactically with protamine, bleeding was normal or only slightly increased. In 3 patients who received protamine because of hemorrhage, mean anti-Xa and anti-IIa were 2.3 and 0.54 U before and 1.32-0.06 U after neutralization. Bleeding was stopped by a second dose of protamine in 1 patient, but blood loss was abnormal in the other patients. However, a correlation between bleeding and anti-Xa or anti-IIa activities was not clearly evident.

Heterogeneity of Lewis antibodies. A comparison of the reaction of human and animal reagents with synthetic oligosaccharides.

Human as well as animal anti-Lewis reagents were shown to have different binding patterns to synthetic structures chemically related to the Lewis epitopes. Two main types of cross-reactions were found: (1) Cross-reactions among type 1 Lewis epitopes (Lea, Leb and Lewis disaccharide). This type of cross-reaction among different type 1 structures was predominant in anti-Lea reagents (16 out of 18), although it was also present in some anti-Leb reagents (4 out of 14). (2) Cross-reactions of Lea and Leb with their type 2 isomers X and Y. The Leb-Y cross-reaction was more frequent (7 out of 14) than the Lea-X cross-reaction (2 out of 18). The serological property of some anti-Lewis reagents reacting with cord cells ('Lex') is also shown to be heterogeneous although probably related to common features of the type 1 Lea and Leb epitopes and independent of the type 2 X and Y epitopes.

[Report of a new radioimmunologic technic for the assay of HBs antigen]. / Présentation d'une nouvelle technique radio-immunologique pour la détection de l'antigène HBs.

We tested a new radiometric assay (Hépatube Wellcome) using a complete automatic device, in hepatitis B surface antigen detection with I 125 marked antibody. The additional advantage of this reagent is its very long life-span (twelve weeks after the date of manufacture). The hepatube system is fully automatic, micro processor-controlled and designed to complete all washing and tracer addition steps in the hepatube test sequence after addition of the patient's sample. The results were compared in the same protocol with those obtained by the method currently used in our group (Ausria II 125). This study has been carried out on 7.589 sera or plasma samples; blood donors 5.352; medical and chirurgical patients 1.292; sera panel 87; repeated tests 367; positives and negatives control sera 421; assays ran the first day 70 The 153 positive results (2.3%) were confirmed by another assay before neutralisation. The sensitivity of both techniques was compared using a reference panel containing samples showing varying degrees of positivity, and representative of both main subtypes. We repeated the assay on this panel 2 months after issue of materials and again 3 months later. This new system is more sensitive than Ausria II 125. Of 6 644 patients the false positive was found in 1,1% of the cases, this was superior to the results found with Ausria II 125 but there is no false negative with this new method. There was no difference when serum or plasma was used.

[Screening of carriers of antitetanus antibodies in blood donors]. / Dépistage des porteurs d'anticorps antitétaniques chez les donneurs de sang.

A screening of antitetanic antibody (AcAT) carriers has been carried out in 4770 blood donors. The percentage of "positive" subjects (with a rate of AcAT greater than or equal to 5 U.I./ml according to Laurell's method) is relatively high: 6,62%. The aim of a statistical study is to find out the distribution of AcAT carriers according to different factors: the chi 2 test allows us to conclude that the relation between the frequency of "positive" AcAT carriers and the blood groups is not significant but there is a significant connection between the frequency of "positive" AcAT carriers, sex and age. Our conclusions agree with those of authors having performed the study after vaccination. Our study has a double advantage: it allows us to know the vaccination state of the blood donors before any vaccination and allows the collecting of "positive" serum samples without having to wait for the vaccination.

[Prevalence and seasonal variations of irregular alloantibodies, especially the anti-Lewis]. / Fréquence et répartition saisonnière des allo-anticorps irréguliers, en particulier anti-Lewis.

In order to determine the efficiency of a technical modification of the screening procedure for irregular antibodies, the authors compare results obtained upon two patients' groups. Group I: 47.638 tests done by classical technics (462 antibodies: 105 anti-Lewis and 357 non Lewis antibodies). Group II: 22.437 tests done by the new method (563 antibodies: 262 anti-Lewis and 261 non Lewis antibodies). This new screening procedure is more efficient than classical technics and put in a prominent position the actual frequency of Lewis antibodies. The relationship between Lewis antibodies, ABO blood groups and sex are discussed. It seems to be an accumulation of Lewis antibodies within group A and AB. The frequency of group O is decreased among patients with Lewis antibodies. There is no modification of the frequency of B blood group. The authors suggest that a quantitative relationship exists between ABO phenotype, secretor status and the occurrence of Lewis antibodies. There is no sex difference in the frequency of Lewis antibodies. A seasonal variation in the frequency of irregular antibodies is reported, with a maximum into hivernal months.

[Frequency of hepatitis after extra-corporeal circulation]. / Fréquence des hépatites après circulation extra-corporelle

In cardio-vascular surgery the risk that the hepatitis-B (H.B.) virus be transmitted was measured in 3 groups of patients (Professor Ch. Dubost), before and since systematic screening for HBS antigen in donors' blood. The same questionnaire was sent to each patient in each group 6 months after extra-corporeal-circulation (ECC), in order to determine the efficiency of HB virus screening tests. The present study gives the following results: --in the first group (no screening for HBS antigen in donors' blood), the frequency of icteric hepatitis was 6.7% (26 cases of jaundice, probably due to hepatitis viruses, out of 386 ECC); --in the second group (screening for HBS antigen in donors' blood by immuno-diffusion (often made after transfusion of fresh blood) the frequency of icteric hepatitis after transfusion of HBS antigen positive blood); --in the third groups, icteric hepatitis was less frequent (4.6%) since systematic screening for HBS antigen by counter-electrophoresis and complement fixation was performed (29 cas out of 629 ECC). Additionally, viral hepatitis appeared more frequently in men than in women, and among older patients than younger ones. Recovery was generally complete in 2 months; however, the evolution of the disease was severe in 3 cases and fatal in one case. In sum, after ECC, hepatitis still remains a frequent side-effect, compelling blood centers to use th most sensitive screening tests now available for HBS screening: radio-immuno-assay and reverse passive haemagglutination tests. As a consequence of the present study, these 2 techniques are being applied on a daily basis in our laboratory for HBS antigen screening tests are ineffective in preventing the transmission of other strains of viral hepatitis by blood transfusion.