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Biomedical subjects

B Habibi

Publications and source records attributed to B Habibi.

At least 19 recordsLinked to original sources

Protease inactivation of the red cell antigen Xga.

The study of the agglutinability of Xg(a + ) cells by several examples of anti-Xga and absorption-elution tests showed that the red blood cell antigen Xga is destroyed by proteases commonly used in blood group serology but not by neuraminidase.

Blood Group Antigens

[Auto-immune haemolytic anaemia and mediastinal dysembryoma in a 6-year-old child (author's transl)].

In a six-year-old girl, suffering from an auto-immune haemolytic anaemia, routine radiological examination revealed the presence of a mediastinal tumour which was removed surgically and proved to be a multiple tissue polycystic dysembryoma. Haemolysis and signs of anti-erythrocyte auto-immunisation disappeared after the operation and total and stable cure obtained with a follow-up of 15 months. The target antigen of the anti-erythrocyte autoantibody could not be found within the tumour. However, the latter contained lymphoid tissue and a considerable quantity of antibody. Although indirect, these findings offer arguments in favour of the secretion of autoantibodies by the dysembryoma.

Anemia, Hemolytic, Autoimmune

The antigen Duclos. A new high frequency red cell antigen related to Rh and U.

An antibody is described which defines a new high frequency red cell antigen, Duclos, whose expression seems to require the presence of both U and Rh fundamental antigens. Apart from the antibody maker's own red cells the only nonreactive samples were from Rhnull U impaired individuals, one example of which was shown however to yield very slight amounts of antibody through absorption-elution tests. Rhmod U weak cells gave very depressed and Rhnull U positive or Rh common U negative cells moderately depressed reactions. The proposita's red cells had an apparently normal Rh-LW condition but their U antigen was significantly decreased. No further Duclos negative individual was found by screening 8,500 blood donors in the Paris area.

Aged

Fine-structural changes in the nucleus of primordial oocytes in immature hamsters.

This study reports observations on fine-structural changes in the nucleus of the oocyte in hamsters during the establishment of the primordial (unilaminar) follicle at 7 to 12 days after birth. Following pachytene, the nuclei at early diplotene contain simple chromosomal cores surrounding by a sheath of fibrillo-granular material symmetrically disposed in the form of lateral projections and loops. From 9 days onwards increasing numbers of the oocytes show nuclei lacking such chromosomal threads: instead, they contain randomly disposed, condensed fibrillar clumps with associated dense knots of material, and prominent aggregations of 25--30-nm granules. This second nuclear form is assumed by all oocytes examined at 11 and 12 days and appears to be the definitive diplotene phase. These changes in the appearance of the nuclear chromatin are discussed in the light of those found in oocytes of other species, and it is concluded that the hamster diplotene phase consists of a transitory 'compace' or uniform lampbrush stage, followed by a definitive dictyate condition like that in the rat, but with markedly differential condensation or extreme diffusion of lateral loops. This conclusion is examined in relation to findings which report a marked increase in the sensitivity of hamster oocytes to X-radiation at the time that the observed changes in nuclear configuration are taking place. The combined observations support the hypothesis that the dictyate stage in rodent oocytes represents a modified diplotene phase in which the high degree of spatial diffusion of components of chromosomes of the lampbrush type results in a reduced capacity for repair following exposure to ionizing radiations.

Animals

[Antigen Fyx: quantitative study of subjects FybFyx, FyaFyx and FyxFyx from two new families].

Two new families are described in which multiple examples of antigen Fyx are found in homo-and heterozygous states. The expression of the antigen is evaluated by conventional methods (agglutination scoring) and HD50 assays using a polybren-citrate autoanalyzer technique. Individuals from both families are tested in parallel with those from the family of the first known examples of homozygous FyxFyx described by Cedergren and Giles [2], and with 59 known FyaFyb and FybFyb controls. No consanguinity is found in the two families reported. Quantitative study of anti-Fyb absorption by red cells reveals that the expression of Fyb in individuals considered to be FybFyx is weaker than in FybFyb and even FyaFyb controls. HD50 assay data obtained in the control donors population seem to indicate that, in contrast to the admitted opinion, intermediate degrees of antigenic strength do exist between "normal" Fyb and Fyx the definition of which, based on quantitative criteria, remains unprecise. Using a new potent anti-Fy3 (AR), the expression of Fy3 displayed a slight and variable decrease in FyxFyx samples investigated.

Blood Group Antigens

An unusual case of leukemia with high fetal hemoglobin: demonstration of abnormal hemoglobin synthesis localized in a red cell clone.

A high level of fetal hemoglobin was found in an 8-yr-old boy without any hematologic disorders except for a moderate anemia. The absence of hemoglobin abnormalities in the parents led us to suspect a latent malignant disease that, on follow-up, was confirmed to be myelomonocytic leukemia. Hemoglobin biosynthetic studies provided evidence of unbalanced synthesis of globin subunits by reticulocytes, while the production of non-alpha chains was equal to that of alpha chains in bone marrow cells. The expression of red cell antigen i was increased, while those of I, A, and A1 antigens were found to decrease progressively. Two populations of erythrocytes, A-positive and A-negative, were distinguished and could be separated by differential agglutination. Unbalanced globin chain synthesis, increased fetal hemoglobin, and antigenic changes of the membrane were shown to be restricted to the A-negative population. The biologic data were not entirely consistent with a genuine reversion to fetal erythropoiesis. The question remains of a polychromosomal lesion of either quiescent F cells or adult stem cells.

ABO Blood-Group System

An unusual Rh phenotype indicating heterogeneity of the Cw antigen.

A family is reported in which a new Cw antigen occurred in two generations. This was recognized by 17 anti-Cw sera, but by none of the 21 anti-C sera which were, however, shown to react strongly with common Cw+ cells. This unusual finding provides evidence that the Cw antigen is in fact heterogeneous. On the basis of data obtained from absorption-elution and coagglutination studies a tentative explanation is attempted: common Cw+ phenotypes are assumed to be Cw (+1+2) and the present phenotype Cw (+1-2). Anti-Cw sera should accordingly be anti-Cw1, whereas anti-C sera should only react with Cw2.

Antigens, Heterophile