Antiphospholipid antibodies are a heterogeneous group of immunoglobulins with specificity for a number of phospholipids, phospholipid-binding proteins and phospholipid-protein complexes. The association between antiphospholipid antibodies and a variety of pathologic disorders, such as arterial and venous thrombosis and recurrent pregnancy loss is recognized as Antiphospholipid Syndrome. The immunoassay currently used to detect antiphospholipid antibodies is the anticardiolipin test. Anticardiolipin antibodies are believed to be polyspecific antibodies that cross-react with all the anionic phospholipids. Therefore, testing only for anticardiolipin antibodies does not always permit detection of all antiphospholipid antibodies, specially when only IgG are evaluated.In a selected population of 74 idiopathic and secondary deep venous thrombosis patients, IgG anticardiolipin, antiphosphatidylinositol and antiphosphatid~lserineantibodies were detected by solidphase immunoassays. Our results show that by testing for each antiphospholipid family, many patients, not evidenced by the standard anticardiolipin assay, were found to be antiphospholipid-positive. The anticardiolipin positive patients have always low, moderate or high levels of antiphospholipid antibodies, suggesting that the antiphospholipid positivity is predictive of anticardiolipin positivity. It should be noted that the patients with only antiphosphatidylinositol positive antibody have a story of nervous system pathology. The meaning of these results is at present under discussion.

The incorporation of 3H-thymidine has been studied in the hepatocytes nuclei of rats during the first 3 days of life. The synthesis of DNA which occurs in lWO of nuclei after a single injection of the labelled precursors 2 h after birth, cannot be considered as premitotic since:(i) The hepatic cell number is constant during the first 3 days of life.(ii) The mitotic index is less than O.l(:,, 20 times lower than that expected on the basis of the labelling index and of the length of cellular cycle.(iii) The percentage of labelled nuclei does not increase in the following 3 days.(iv) the average number of grains per nucleus is unchanged for 18 h after the injection, a period longer than an entire cellular cycle (13 h).This synthesis is better explained as due to an increase of DNA content per nucleus, previously described, in the hepatocytes during the first 3 days of life.After 20 h of life (18 h after label injection) a decrease of label of about 30",, takes place without variation of DNA-Feulgen dye content per nucleus. It is concluded that synthesis and turnover of DNA are present in the hepatocytes nuclei and that these processes are probably related to the functional maturation of the cells.

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