[Dynamic study of osmotic resistance of red cells in sickle cell anemia (author's transl)]. / Etude dynamique de la résistance osmotique des globules rouges drépanocytaires

A study of the osmotic resistance of red cells from normal subjects (AA), patients with the sickle cell trait (heterozygous subjects) (AS) and homozygous subjects (SS) was carried out using a dynamic automatic micro-method: Danon's fragiligraph, permitting one to obtain simultaneous recording of cumulative and derivative curves of the hemolytic process. 15 samples of red cells of each of the three categories were studied. Fragiligrams obtained from SS red cells showed that they became hemolysed later and in a more progressive fashion than the normal red cells AA. The AS red cells occupied an intermediate position. 5 samples of each category of red cells were studied after various times of incubation in the presence of a reducing substance (sodium metabisulphite). It was shown that the red cells containing hemoglobin S were still more resistant to osmotic hemolysis when hemoglobin was in the deoxygenated form and this proportional to the quantity of deoxygenated hemoglobin, without the brutal process of sickling producing any special modification in the shape of the curve. The role of the membrane is considered.

Familial hypertrophic cardiomyopathy. Cardiac ultrasonic abnormalities in genetically affected subjects without echocardiographic evidence of left ventricular hypertrophy.

AIMS: It is not known whether the apparent normality of echocardiographic examination results, in subjects bearing a mutation for hypertrophic cardiomyopathy but without ultrasonic left ventricular hypertrophy, is due to incomplete phenotypic expression, or inaccurate echocardiographic criteria. The aim of this study was to search for echocardiographic abnormalities in these patients. METHODS AND RESULTS: Echocardiography was performed in 100 subjects from two families with a mutation in the beta-MHC (720) or My-BPC (714) genes. We compared genetically affected subjects with an apparently normal left ventricle (thickness < 13 mm) (20 patients), and nonaffected first-degree relatives (61 normal subjects). (1) Patients had a thicker left ventricular wall (9.7 +/- 1.4 vs 8.9 +/- 1.4 mm, P = 0.03), a greater indexed mass (107 +/- 18 vs 97 +/- 17 g. m-2, P = 0.03), a larger left atrium (27 +/- 9 vs 23 +/- 10 mm3, P = 0.09) and lower wall stress (78 +/- 11 vs 89 +/- 15 10(3) dynes. cm-2, P = 0.002); these differences were highly significant after adjustment for height, age and systolic blood pressure either for wall thickness (P = 0.000003), mass (P = 0.005) or atrial volume (P = 0.001), and the ventricular systolic dimension appeared smaller (P = 0.01); (2) results remained significant (P < 0.01) when a lower cut-off value (< or = 11 mm) or only adults (> or = 18 years) were considered; (3) a subanalysis of Family 714 (13 patients, 25 normals matched for sex, age and height) showed the same trends. CONCLUSION: In familial hypertrophic cardiomyopathy, genetically affected subjects with an apparently normal heart by echocardiography show slight ultrasonic structural and functional left ventricular modifications, suggesting that the phenotype of the disease is a continuous spectrum from normal structure to typical hypertrophy.