Normal repair of gamma radiation-induced single-strand and double-strand DNA breaks in retinoblastoma fibroblasts

The formation and repair of gamma radiation-induced DNA damage were examined in fibroblasts from individuals with retinoblastoma. Utilizing the alkaline elution technique to study single-strand DNA breaks and the nondenaturing elution technique to study double-strand DNA breaks, cultured cell strains from two patients with bilateral retinoblastoma and one patient with sporadic retinoblastoma were shown to develop the same number of DNA breaks as cells from normal individuals after exposure to various gamma radiation doses. Furthermore, the rate and extent of rejoining of both single- and double-strand DNA breaks induced by gamma radiation in retinoblastoma fibroblasts were also normal Defective DNA break repair does not appear to explain the marked predisposition to second malignancies and the possible in vitro radiation sensitivity which are associated with hereditary retinoblastoma.

Atypical transmission of ABO blood groups in a French family

A group AB mother (Mrs P.D.) gave birth to a group O female baby (C.D.). Extensive study of the blood group genetic markers in both the parents and the child, carried out on several occasions, showed nothing unusual outside the ABO system. Mrs P.D. then, gave birth to a second female baby who was also group O. Mrs P.D. had normal amounts of A, B, H and Lewis antigens in her saliva. The H, A and B agglutinability of her red cells was in the range of normal A2B group. This A2B blood group was characterized by very low A gene-specified glycosyltransferase activity in serum. Moreover this activity was undetectable in red blood cell membranes. These results are discussed in the light of various hypotheses in order to explain this unusual transmission of ABO blood group.

Immunologic evaluation of T chronic lymphocyte leukemia cells: correlations among phenotype, functional activities, and morphology

Chronic lymphocytic leukemia of T-cell origin (T-CLL), a rare variant of CLL, appears to be a clonal proliferation of mature T cells of one of several subsets. In the cells of 7 T-CLL patients, surface markers (including those reacting with a panel of monoclonal antibodies), functional activities, and electron microscopic morphology were evaluated. The phenotypic patterns of circulating T-CLL cells correspond to those of normal mature T-cell subsets. The cells of three patients demonstrated at least one marker reported to be expressed by suppressor/cytotoxic T cells: those of three patients expressed markers apparently linked with T-helper activity. Cells from one patient appeared to be a heterogeneous proliferation of more than one T-cell subset. These T-CLL cells may also retain some of the functional activity of the normal T subpopulations. Our data indicate that a combination of several tests should be used to characterize the proliferating cells in T-CLL.

Use of microcarriers to isolate and culture pulmonary microvascular endothelium

Microcarriers of known diameter can be used to collect endothelial cells from microvessels of the same or slightly smaller internal diameter. The procedure is illustrated by collection of endothelial cells from rabbit pulmonary pre-capillary vessels. The lungs are perfused free of blood with physiological saline and then cold vessels. The lungs are perfused free of blood with physiological saline and then cold (4 degrees C) saline (containing EDTA, 0.02%, and microcarriers 600/ml; 40-60 micrometers diameter) is perfused via the pulmonary artery. The direction of flow is reversed periodically to collect the bead-cell harvest from the arterial side. Cold shock and EDTA cause the endothelial cells to detach from the vessels under conditions such that the cells remain attached to the microcarriers. The selective attachment to microcarriers is apparently aided by the tight fit of the beads within vessels of the same diameter. Beads do not emerge on the venous side, all being trapped at the pre-capillary level. Electron microscopic examination of lungs fixed during the perfusion shows that the beads lodge in terminal arterioles and pre-capillary vessels (approximately 40-60 micrometers in diameter, with one, sometimes incomplete, muscle layer). Endothelial cells recovered on microcarriers can be allowed to migrate on to flasks and back on to beads. The resultant cultures have an endothelial morphology and possess high levels of angiotensin coverting enzyme and carboxypeptidase N activity.

B-cell acute lymphoid leukemia (ALL) with lymphoblasts expressing surface immunoglobulins only at relapse

Morphological, cytogenetic and immunological studies were performed on lymphoblasts of two patients with acute lymphoid leukemia at onset and at relapse. At onset and before any treatment lymphoblasts had L3-FAB morphology, a 14q+ chromosome abnormality due to a 8;14 translocation in the absence of expression of specific immunologic markers (E-rosette, C3-receptor, surface immunoglobulins). The clinical behaviour of the two patients was characterized by a very short first complete remission and by a short survival. At relapse SIg was expressed by lymphoblasts of both patients. This evolution in immunological phenotype of the dominant blast populations from onset to relapse provides evidence that in vivo, during the course of the leukemic disease, phenotype changes take place that seem to be cell differentiation.

Cyproterone acetate in advanced male breast cancer

Three male patients of 55, 63 and 71 years of age, with metastatic breast cancer, were treated with cyproterone acetate. Two patients showed complete remission, one lasting 21 months, another 51+ months and a third achieved partial remission lasting 9 months. These results suggest that cyproterone acetate may be useful in the treatment of advanced male breast cancer.

Mechanism for strand-break induction in DNA-proflavine complexes exposed to visible light

Proflavine bound-superhelical phi XRFI DNA Molecules undergo single-strand scission upon irradiation with visible light at high fluence rate. As shown by agarose gel electrophoresis analyses, the nicking reaction is (i) oxygen-dependent, (ii) strongly inhibited by catalase and an electron scavenger such as cystamine, and (iii) totally suppressed by ceruloplasmin and radical scavengers such as t-butanol sodium benzoate. This indicates that H2O2, e-, O2 and OH, respectively, are involved in the cleavage process. NaN3, a singlet-oxygen quencher, has very little effect on strand-breakage but it prevents almost completely the alteration of guanine residues (a lesion already observed after irradiation at low fluence rate). Since, in the presence of NaN3, strand scission can occur and guanine (as the other bases) recovered intact, it follows that the radical intermediates produced during breakages are probably not involved in any permanent modification of the DNA bases.

Acute lymphocytic leukemia and complement receptors. (A study of 45 cases)

The expression of complement receptors (C3R) associated or not to sheep erythrocyte receptors (ER) and surface membrane immunoglobulins (SmIg) was determined on lymphoblasts of 45 patients with acute lymphocyte leukemia (ALL) at onset and/or in the first relapse. We found C3R simultaneously expressed with ER or SmIg on lymphoblasts of T cell ALL and B cell ALL. Lymphoblasts were positive for C3R in absence of ER and SmIg only in three patients in the hematological relapse. We stress the importance to find C3R as independent marker on ALL cells at onset and in subsequent relapses.

Mevinolin: a highly potent competitive inhibitor of hydroxymethylglutaryl-coenzyme A reductase and a cholesterol-lowering agent

Mevinolin, a fungal metabolite, was isolated from cultures of Aspergillus terreus. The structure and absolute configuration of mevinolini and its open acid form, mevinolinic acid, were determined by a combination of physical techniques. Mevinolin was shown to be 1,2,6,7,8,8a-hexahydro-beta, delta-dihydroxy-2,6-dimethyl-8-(2-methyl-1-oxobutoxy)-1-naphthalene-hepatanoic acid delta-lactone. Mevinolin in the hydroxy-acid form, mevinolinic acid, is a potent competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase [mevalonate: NADP+ oxidoreductase (CoA-acylating), EC 1.1.1.34]; its Ki of 0.6 nM can be compared to 1.4 nM for the hydroxy acid form of the previously described related inhibitor, ML-236B (compactin, 6-demethylmevinolin). In the rat, orally administered sodium mevinolinate was an active inhibitor of cholesterol synthesis in an acute assay (50% inhibitory dose = 46 microgram/kg). Furthermore, it was shown that mevinolin was an orally active cholesterol-lowering agent in the dog. Treatment of dogs for 3 weeks with mevinolin at 8 mg/kg per day resulted in a 29.3 +/- 2.5% lowering of plasma cholesterol.

Different H deficient phenotypes present in one kindred

Two different H deficient phenotypes are observed in one kindred. Three of them in two generations of a same family appear as Bombay like. In the other branch of the kindred, an Hz phenotype (as described in the editorial of this issue) is observed. The most simple explanation is that the three Bombay like phenotypes correspond to Hz ABH non secretor (Hz sese) individuals, this being indistinguishable from a true Bombay. The high level of I antigen in the plasma of the three Bombay like (as observed in Hz in contrast to true Bombay) could favour such an hypothesis. According to ORIOL'S new hypothesis [5], III2, III3 and IV2 would genetically be hh sese, III8 would be hh Se and the h Se would therefore be a recombining haplotype (the original haplotype being h se).

Activity of IgG and IgM ABO antibodies against some weak A (A3, Ax, Aend) and weak B (B3, Bx) red cells

The IgG and IgM anti-A and anti-B activities from several immune and non-immune O, A and B sera were tested against a panel of weak (A (A3, AX, AND Aend) and weak B (B3 and Bx) red cells. In all cases it is the IgM which agglutinated optimally Ax (or Bx) cells, while IgG and IgM anti-A (or anti-B) reacted similarly with A3 and Aend (or B3) cells. The agglutinating activity of all these ABO antibodies was found straightly related to their association constant for the A (or the B) receptor.

[Development of antigens ABH and Ii in children between 0 to 16 years old]

The ABH and I, i erythrocyte antigens of 926 children from birth to sixteen years were tested in a semi-quantitative assay in order to follow their development. Results show that total activities of A, B and H erythrocyte antigens are reached within 13 and 24 months, the main modifications being observed within the first three months of life. However, these activities depend on the agglutinins used in the test; notably the results with anti-H lectins from Ulex europaeus and Laburnum alpinum are not totally identical. The decrease of i reactivity and the increase of I reactivity are simultaneous, but at birth the I reactivity of cord red cells is widely distributed, while that of i is more homogeneous. The increase in H activity tested with Laburnum alpinum is directly related to the decrease of foetal hemoglobin in the children's red cells.

[K-Lymphocyte cytotoxicity: role of human blood group ABO, rhesus and P alloantibodies]

Using human erythrocytes of known antigenic density, sensitized by ABO and Rhesus (D) alloantibodies, it is shown that K cell cytotoxicity mediated by peripheral blood lymphocytes is directly correlated with the number of IgG molecules specifically bound to the target cell surface. The lytic sensitivity of P1k but not P2 or p erythrocytes coated with anti-Tja (anti-P + P1 + Pk) antibodies, demonstrates that effector K cells are mainly triggered through the IgG ANTI-Pk component of such sera.