[Risks of confusion in the laboratory detection of drepanocytosis (author's transl)]. / Les pièges du diagnostic de ls drépanocytose au laboratoire.

A brief review of the most usual methods for detecting hemoglobin S, their principles, their limits and interpretations. The author, then, considers the identification of hemoglobin S either isolated or associated with other abnormal hemoglobins or with thalassemiae. He emphasizes the techniques preventing some confusion in results interpretation. Problems in identifying HbS in new-born baby are also considered.

[Note on the detection of hemoglobin lepore in a Senegalaise (author's transl)]. / A propos de la découverte d'une hémoglobine Lepore chez un Senegalais.

After reviewing briefly the characteristic features of hemoglobins Lepore, their distribution and their clinical symptoms, the authors report on a senegalese case.

[HBs antigen in rural population of Senegal (author's transl)]. / Antigene HBs dans les populations rurales du Senegal.

The prevalence of HBs Ag has been determined by counter-immuno-electrophoresis among 16,006 Africans of all ages and both sexes living in 132 villages chosen at random in whole Senegal. 8,83 +/- 0,5 p. 100 of the examined people were positive for HBs Ag. HBs Ag is much more frequent among males (11,1 p. 100) than females (7,0 p. 100). Almost non existent before the age of 1, prevalence increases during childhood and reaches its summit between 10 and 14 years for boys (14,7 p. 100) and between 20 and 24 for women (10,1 p. 100), then it decreases regularly with old age and become negligible over 60. Ethnic factors and way of living are more important than geographical factors. Subtyping demonstrated the importance of contamination inside families and consequently the preponderance of oral over percutaneous transmission.

Properties of the double substituted hemoglobin C Ziguinchor alpha2A beta 2 6 Glu replaced by Val 58 Pro replaced by Arg.

We have previously described the structural identification of the sickle hemoglobin variant Hb C Ziguinchor (alpha2A beta2 6 Glu replaced by Val, 58 Pro replaced by Arg). This hemoglobin was found in two generations (three members) of an African family. In two family members, the clinical picture resembled that typical of a sickle cell trait, while the third member showed a more extreme clinical condition due to complication by an iron deficiency anemia. The functional properties of Hb C Zig. in red blood cells or in dilute solutions were identical to those of Hb S. The gelling behaviour of deoxy Hb C Zig. was also indistinguishable from that of Hb S. These findings suggest that, in contrast to the case of Hb C Harlem, the second substitution in position beta58 in Hb C Zig. does not interfere with the intermolecular interactions determined by the sickle substitution.

Hemoglobin Dakar = Hb Grady: demonstration by a new approach to the analysis of the tryptic core region of the alpha chain and oxygen equilibrium properties.

Preliminary studies have suggested that in Hb Dakar, histidine alpha112 was substituted by a glutamine. A re-investigation on this hemoglobin is presented in this report. A structural study has been performed using a new approach to analyse the tryptic core region of the human hemoglobin alpha chain. After tryptic digestion of the aminoethylated alpha chain, a secondary digestion of the tryptic core was carried out with chymotrypsin and with another protease, thermolysin. Analyses of the chymotryptic and thermolytic peptides indicated that the structure of Hb Dakar was identical to that of Hb Grady previously described by Huisman et al. who showed the insertion of three amino acid residues in position alpha115 or alpha118. The insertion, which was localized near two residues involved in the alpha1beta1 contact, did not produce a dissociation into dimers. Functional studies demonstrated a a slightly increased oxygen affinity, a lowered cooperativity and a normal Bohr effect. The low amount of the abnormal hemoglobin (8%) may in part be explained by a slight instability of the molecule.

[Fluorescent antibodies in the cerebrospinal fluid and serum of patients suspected of cerebral malaria caused by Plasmodium falciparum]. / Anticorps fluorescents dans le liquide céphalo-rachidien et le sérum de malades suspects de neuropaludisme à Plasmodium falciparum

The authors report the results of indirect immunofluorescent technique used for detecting malarial antibodies in the cerebrospinal fluid and serum of 126 African patients suspected of cerebral malaria from infection with Plasmodium falciparum. Almost all of them were less than 15 years old and were living in urban unstable hypoendemic areas. Malarial antibodies, mainly IgG, were found in about 25 0/0 of cerebrospinal fluid samples, whether the patients were admitted for malaria or for any other disease. Malarial antibodies were more frequently found in cerebrospinal fluid of patients over 2 years old and in those not treated with antimalarial drugs before hospitalization. No correlation was found between serum antibody level, parasitemia, splenomegaly, clinical form, precocity of blood collection and malarial antibodies in the cerebrospinal fluid. The results concerning serum antibodies corroborate previous works.

[Hemoglobin C -- beta-thalassemia disease and homozygous beta-thalassemia in a black African family (author's transl)]. / Hémoglobine C -- beta-thalassémie et beta-thalassémie homozygote dans une famille Noire Africaine

The study of a Malian family has allowed to prove existence of two types of beta-thalassemia genes: the beta0 gene which suppresses the synthesis of the beta chain into cis position and the beta+ gene which slows down only partially this synthesis. The difference between this two genes has been possible owing to the hemoglobin C found in this family and induced by the betaC mutated gene. The segregation of the four genes betaA, betaC, beta0 thal, and beta+ thal. has allowed to compare all the possible phenotypes deriving from the combinations by two of these allelic genes.