DNA complementary to mRNA extracted from the thyroid glands of patients suffering from medullary carcinoma of the thyroid (MCT), a calcitonin‐producing tumour, was inserted in the Pst site of pBR 322 by G‐C tailing. The recombinant plasmids were used to transform Escherichia coli DP 50. Ampicillin‐resistant clones were screened using a 32P‐labelled cDNA to mRNA extracted from a case of MCT particularly rich in calcitonin (CT) mRNA. Positive clones were subsequently rescreened using a 32P poly(T) probe. Eighty clones were thus purified, and the inserts obtained by digestion with PstI were subjected to positive hybridization selection with subsequent translation in vitro. An insert stimulating synthesis of the protein and containing restriction sites compatible with the previously published complete sequence of calcitonin mRNA from rat was sequenced. This cDNA insert contained the entire coding region of 426 bp, 70 bp at the 5′‐end, and 295 bp upstream from the poly(A) tail. The complete amino acid sequence of human preprocalcitonin could thus be deduced.

The targeted gene inactivation of endothelins-1 and -3 (ET-1 and ET-3) and of one of their receptors, ETB, in the mouse causes severe defects in the embryonic development. These defects, cardiovascular and craniofacial malformations for ET-1, and colonic agangliogenesis associated with skin pigmentation anomalies for ET-3 and the ETB receptor, reproduce pathological phenotypes due to natural mutations of the same genes in the mouse and the human. The mutant phenotypes have been causatively linked to deficient migration/proliferation/differentiation of neural crest cells, i.e., neurocristopathies. To bring new insight about the exact roles of ETs in development and the involvement of neural crest cells in these processes, we have explored, by in situ hybridization, the ontogeny in the early human embryo of the ET system (ET-1 and ET-3, ETA and ETB receptors, ET converting enzyme-1). ET receptor mRNA expression in neural crest cells starts at 3 wk of gestation and continues during the entire period studied (up to 6 wk of gestation). During this period, ETA expression progressively spreads to undifferentiated mesodermal components of various structures and organs (head and axial skeleton, lateral and ventral subdermal mesoderm), whereas ETB expression remains more restricted to fewer differentiated cells (neural tube, sensory and sympathetic ganglia, endothelium). Some of these tissues and structures that express either one of the receptors do not appear to be of neural crest origin. In the digestive tract and the cardiovascular area, the present observations on the sources of ETs and their target cells in the young embryo provide the basis for a dynamic interpretation of the results of gene targeting of the mouse and the human phenotypes, and point to other possible roles of ETs in other ontogenetic processes. The results support the concept of local, rather than hormonal, interactions between the sources and targets of ETs during development.

A case of acquired hemolytic anemia of 12 years’ duration showing a permanent polyagglutinability for at least 9 years, is presented. 1. Polyagglutinability is due to the presence on the surface of the patient’s erythrocytes of an antigen unknown up to the present time, which is independent of antigens T and H and does not behave like a normal antigen modified by proteolytic enzymes. It has been designated by the letters Tn. The Tn substance is not secreted in saliva. This antigen has not been found on the erythrocytes of 25 members of the patient’s family. 2. The substance which induces agglutination (natural anti-Tn) was found to be present in the serum of 473 white adults and 33 adult Negroes. It was absent or weak in 28 sera from cord’s blood. It acts like a complete antibody, being active in saline at the temperature of laboratory and then inducing massive clumping of Tn red cells. Through absorption and elution studies and through sensitization in rabbits, we have been able to demonstrate that anti-T and anti-Tn are distinct. 3. There are in our patient’s serum: (a) a substance specifically active against Tn erythrocytes treated by trypsin; this may be an immune anti-Tn; (b) a nonspecific incomplete antibody weaker than the anti-Tn and active against all varieties of red cells treated by trypsin; (c) an incomplete anti-E; (d) a cold antiplatelet substance; and (e) an immune antileukocyte antibody. These three last antibodies are very probably due to transfusions. 4. To explain the combination of an acquired hemolytic anemia and polyagglutinability, two hypotheses are presented: (a) The acquired hemolytic anemia has no relationship to the existence in the patient of a very rare group antigen, perhaps confined to one family. (b) The hemolytic anemia is directly related to the existence of the Tn antigen on our patient’s red cells and is due to the development of an immune anti-Tn antibody against the Tn antigen, this last antigen being either a group antigen or an antigen revealed or modified by the causal agent of the disease.

The reliability of the automatic determination of the ABO group on the Groupamatic is explained and backed up with an experience of 600,000 runs. Provided the user observes the rules of conventional serology, this reliability depends upon three essential, combined actions of the machine: identifying the sample, reading serological reactions, processing and printing-out grouping data. Figures taken from 150,000 ABO groups enable us to compare the frequency of detected weak A sub-groups with known properties ; tests performed on samples of chimeras or of Bombay phenotypes, associated with experimental work on artificial chimeras, confirm the high reliability this automatic system provides.