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Biomedical subjects

M L North

Publications and source records attributed to M L North.

At least 19 recordsLinked to original sources

[Epidemiology of genetic hemoglobin diseases in metropolitan France].

The number of subjects with heterozygous beta-thalassaemia and sickle-cell anaemia in metropolitan France can be evaluated by the distribution of populations originating from countries with a high prevalence of genetic haemoglobinopathies. Taking into account the movements of these populations observed since the 1982 census, the current prevalences of beta-thalassaemic and drepanocytic traits are higher than the figures of 180,000 and 130,000 respectively found at that date. On the other hand, it appears from episodic screenings performed during the last few years that the percentage of subjects with heterozygous beta-thalassaemia is 3.09% in Corsica, 0.77% in school-age population in the Marseille area, and 0.72% in the general population of Marseille, Toulon and Nice. In 1992, the number of patients with heterozygous beta-thalassaemia and with major sickle-cell syndrome is estimated at 250-350 and 1000-3000 respectively. Patients with sickle-cell anemia predominate in the Paris area, whereas those with heterozygous beta-thalassemia predominate in the provinces, notably in the Provence-Côte d'Azur and Corsica regions.

Anemia, Sickle Cell

Lack of linkage between acute intermittent porphyria and the A and B loci of the HLA system.

Forty-six members of a family known to have Porphyria were studied. As the disease is often latent clinically, erythrocyte uroporphyrinogen I synthetase activity was determined to classify the subjects as being healthy or carriers. HLA--A, B, C, Bf, GLO antigens were determined. No linkage between acute intermittent Porphyria and the HLA system was noted in this family.

Acute Disease

G6PD Vientiane: a new glucose-6-phosphate dehydrogenase variant with increased stability.

A new G6PD variant, called G6PD Vientiane, has been discovered in a patient from Laos. The characteristics of this variant are: mild enzyme deficiency (about 50% of the normal activity) in the granulocytes and the red cells, with normal G6PD-related antigen concentration; increased stability; normal Km glucose 6-phosphate and NADP+; increased inhibition constant by NADPH; decreased inhibition by ATP; slightly increased utilization of the substrate analogue; abnormal pH curve, with maximum activity at pH 9.5; slightly reduced starch gel electrophoretic migration. The implications of the molecular stability of a deficient mutant variant are discussed.

Adult

[Incidence of monoclonal gammopathies in blood donors].

A routine screening of monoclonal gammopathies (M.G.) was performed in the serum from 36, 015 blood donors by cellulose acetate electrophoresis. The incidence of M.G. was estimated to 0.14 per cent. About 86 per cent of cases can be classified as asymptomatic M.G. and 14 per cent as malignant M.G. (myeloma or Waldenström macroglobulinemia). In asymptomatic forms, heavy chain classes are only IgG or IgM with a large predominance of IgG (86,4%). It is suggested that donors in whom M.G. have been detected should not be allowed to give blood. A yearly clinical, hematological and an immunoglobulin check-up is recommended to these patients in order to defect the first sign of a malignant process.

Adult

A weak human MLR locus mapping at the right of a crossing-over between HLA-D, Bf and GLO.

An unexpected MLR reaction has been observed between three HLA-identical sibs; it consists of bidirectional positive MLR between identical female twins and a sister. No argument for a lymphoid mosaic could be found, although twins were frequent in the family; similarly no HLA-A/B or HLA-B/D recombinant could be demonstrated. The MLR, although weak, was highly reproducible. PLTs could be raised between the sibs, without an apparent segregation in this family nor in five other families, but such PLTs discriminated well between the positive and negative controls. In the absence of any proof that such a weak MLR locus could be on another chromosome than chromosome 6, two lines of argument are indirect evidences that such a locus could be indeed on chromosome 6: one of the sibs differs from the two others for two markers outside HLA--D--DR--Bf: glyoxalate (GLO) and red blood group P.

Blood Group Antigens

Quantitative studies of Gm allotypes. II. G1m(1), G3m(5) and G3m(21) in sera from healthy caucasoid blood donors, and in a family with the inheritance of a gene responsible for a weak Gm1,17;..;21 haplotype.

The quantitative expression of three allotypes--G1m(1), G3m(5) and G3m(21)--has been studied in normal caucasoid sera. A gene dosage effect, previously described for all of these allotypes, is not noticed for G3m(5) in the present study. The different content of G3m(5) and G3m(21) IgG3 molecules in heterozygous Gm5/Gm21 sera has been verified: these contents are respectively 75% and 25% of the IgG3 content. The same allotypes have been studied in a family which shows the inheritance of a weak Gm1,17;21 haplotype. The gene responsible for this abnormality is probably a new regulatory gene, and is transmitted without the 'aimed' haplotype.

Alleles

Human serum albumin variants: determination and repartition of allotypes in 24 cases of bisalbuminemia observed in the French population.

Weitkamp et al. (1973) using starch gel electrophoresis in three different systems of buffers (pH 5, 5.6 and 6.9) distinguish at least 24 genetically determined variants. In the European area only seven variants have been observed. The study of 24 cases of bisalbuminemia observed in the french population by acetate electrophoresis at pH 8.6 and polyacrylamide agarose gel electrophoresis at pH 8.7 and pH 6.9 can distinguish three slower variants than the normal albumin. The most frequent variant is the B type observed in 16 cases. The other types are the Pollibauer type observed in 7 cases, and the Gainsville type in one case only. The incidence of these variants can be estimated to 0.7 p. 1000 individuals.

Blood Protein Disorders

G-6PD "ankara". a new G-6PD variant with deficiency found in a Turkish family.

A new G-6PD varient with enzyme deficiency is described in a 7-month-old Turkish boy without any hemolytic manifestation, except neonatal hyperbilirubinemia. The main characteristics of this variant were the following: Severe enzyme deficiency in erythrocytes (8% of normal), fast starch-gel-electrophoretic mobility (110% of normal), increased Ki NADPH with respect to NADP+, slightly biphasic pH curve, enzyme instability, in vivo and in vitro, decreased molecular specific activity (58% of normal).

Blood Cells

HBs antigen in human plasma fractions.

Therapeutic fractions were obtained by fractionating human plasma containing HBs antigen, by the Cohn ethanol technique modified by Nitschmann. Plasmas with various HBs antigen titers were selected. The antigen was sought in each fraction by the techniques of counterelectrophoresis and radioimmunological detection in liquid phase. With the exception of very pure albumins, all fractions were found to contain the HBs antigen, though in variable proportions. A technique for the purification of albumin, applicable on an industrial scale, is proposed. It makes it possible to obtain an albumin fraction in which the HBs antigen cannot be detected by the most sensitive techniques, even starting with a plasma which is very rich in HBs antigen (titer 1/64 by counterelectrophoresis).

Blood Coagulation Factors

Lymphosarcoma, cold urticaria, IgG1 monoclonal cryoglobulin and complement abnormalities.

A patient with lymphosarcoma and cold urticaria showed evidence of complement activation by the classical pathway with low levels of the early complement components, normal levels of late acting components, normal functioning of the alternate pathway and reduction of the C1-inhibitor level. The serum contained an IgG1 monoclonal cryoglobulin responsible for the complement activation. In vitro tests demonstrated a high capacity of the serum to activate C1.

Cold Temperature