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.

No abstract

The sera of 172 HL-A typed subjects irrirnunized mostly by multiple transfusions were studied and the specificities of the produced H L A antibodies were determined. The probability of non-response against an antigen cross reacting with an antigen of the immunized subject was calculated by the use of Bayes' method. A lower immunogenicity within the main cross reacting groups (CREG) was confirmed: [HI,-A2, W281, [HL-A3,1,11], connected to [HGAlO, W19 (=W29,30,31,32)], [W5, HL-AS, W15,W21], [HL-.47,WlO,W22]. Some antigens were not connected to any CREG: HL-A9,12,13, W27. Others were insufficiently studied in the material to allow definite conclusions: W 18,W 14,HL-A8. An asymmetry of the phenomenon i.e. non reciprocal inhibition of antibody production for two antigens was observed often.The comparison of one part of the rriaterial studied with the platelet complement fixation test, to another part studied with the lymphocytotoxicity technique suggested that the specific inhibition of antibody production was not complete but that such a situation only decreased the frequency and intensity of the response against the antigen.A study of the co-occurrence of various HL-A specificities in the immune sera lead to a similar but somewhat broader description of the GREG.

Plasma beta-thromboglobulin (BTG) was measured in 132 patients with valvular heart disease: 43 were studied before, 89 after surgery (78 mechanical valves and 11 bioprostheses). In this group of 89 selected patients, a history of thromboembolism was present in 53 (5 of them had bioprosthesis). Some abnormalities have been observed in patients with valvular heart disease as compared with controls: decreased platelet count and retention on glass column, and increased BTG. There is no statistically significant difference in BTG level between patients with (m +/- SD: 62.4 +/- 42.0 ng ml-1), or without (59.5 +/- 41.0 ng ml-1) a prosthesis; in the small series of 11 patients with a bioprosthesis, BTG was slightly lower than in other patients (44.5 +/- 14.1 ng ml-1), but still higher than in controls (26.8 +/- 13.3 ng ml-1). In the patients with a history of thromboembolism, BTG was significantly higher (66.7 +/- 47.9 ng ml-1 than in patients without this complication (49.9 +/- 21.0 ng ml-1). Thus, BTG evaluation may have some value in valvular heart disease but, at present, it should be confined to systematic research including prospective studies.

A novel procedure for storing blood at a controlled pH consists in collecting blood in a pH 8.20, Tris-CPD solution and storing it in a special recipient including a gas permeable membrane under a CO2 atmosphere. The recipient is placed in an atmosphere of variable CO2 content, so that the initial alkalinity of the preservative is balanced by dissolved CO2, the proportion of which is diminished when lactate production increases with storage. 2,3-DPG and ATP were studied at three different pH levels of approximately 7.25, 7.45, and 7.65 at 4 degrees C. The best pH for the simultaneous maintenance of 2,3-DPG and ATP was 7.65. Under these conditions, 2,3-DPG is maintained at its initial level and ATP at 55% of its initial level at the 30th day. Lactate production is linear and hemolysis moderate.