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L Baugnet-Mahieu

Publications and source records attributed to L Baugnet-Mahieu.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Aspects of megakaryocytic viral production in relation to lymphocytic leukemia in the rat].

Two viral populations BL/F (EL) and BL/F (SL) were derived from RadLV-Rs by propagation in rats where they induced respectively a generalized lymphoma in 5-6 weeks or a thymic lymphoma killing the animals in 5-6 months. In both cases, 10 days after inoculation of viral extract, numerous viral particles are present in the megakaryocytes (MKC) of the bone marrow and the spleen. Our results suggested a production rather than a passive accumulation of those particles by the MKC. The kinetics of blood platelet level for both leukemias showed a thrombocytopenia corresponding with the macroscopic development of the tumor. Therefore the evolution of the blood platelet level is not related to the MKC viremia. This suggests a lack of direct effect of virus BL/F on the MKC metabolism.

Animals↗
PubMed1981

On the altered nucleocytoplasmic transport "in vitro" of rapidly labelled RNA, in the presence of cytosol or serum from tumor-bearing rats.

Enhanced nucleocytoplasmic RNA transport has been demonstrated by incubating normal rat liver nuclei in presence of cytosols originating from the poorly differentiated, fast-growing hepatoma HW-165, in the linear phase of tumor growth. The effect of hepatoma HW-165 cytosol was reduced or suppressed in presence of small amounts of normal liver cytosol: on the other hand, several polypeptides of molecular weight 20,000 to 40,000 daltons were hardly detectable in hepatoma HW-165 cytosol, both arguments indicating that potentially regulatory proteins should be absent or present in reduced concentration in hepatoma HW-165 cytosol. No modification of RNA release was observed in presence of cytosols originating from the thymus of RNA virus (BL/F)-infected rats, whatever be the time after inoculation. Attempts were made to use the nuclear restriction assay, supplemented with plasma or serum of various origins, as a biochemical marker of neoplasia. In a first series of assays, including 80 cancer patients and 12 healthy controls, the RNA transport activity was stimulated by the serum of patients bearing various tumors (lung cancer, cancer of the respiratory tract, uterine cervix...), except in a few cases of mammary carcinoma, where values equivalent to or lower than the controls were obtained.

Animals↗
PubMed1981

Thyroid influence on the growth of hepatoma HW-165 in Wistar rats.

The development of a fast-growing hepatoma (HW-165) in normal euthyroid Wistar rats, was shown to be stimulated by daily injection of a dose of triiodo-L-thyronine (T3) as low as 1.5 microgram/100 g body weight. Administered to thyroidectomized rats, T3 completely restored the frequency of tumor initiation and accelerated the growth of the hepatoma, which had been considerably slowed down in hypothyroid rats. Contrary to other investigators, working on fast-growing Morris hepatomas, we did not observe any significant increase in the T3 level in the serum of hepatoma HW-165-bearing rats. Similarly, the tetra-iodo-L-thyronine (T4) levels were of the same order of magnitude in the blood of both normal and tumor host animals. The mitotic activity was reduced in hepatomas transplanted in hypothyroid rats and increased in tumors of T3-treated animals. These results support the assertion of Short (20) suggesting a relationship between the mitogenic effects of iodothyronines on the normal hepatocyte and on transplanted tumors of hepatic origin.

Animals↗
PubMed1980

[Ultrastructural characterization of a retrovirus of mice (BL/F) producing leukemia in rats].

Two distinct leukemogenic viral subpopulations, BL/F (EL) and BL/F (SL) were derived from RadLV-Rs by propagation in rats. They were purified from the serum and studied by thin section and negative stain electron microscopy. Their ultrastructural organizations were not found to differ significantly from each other or from other murine leukemia viruses for which a detailed model now exists. Our work constitutes to our knowledge a first indepth study of viruses associated with radiation leukemia. It confirms the MuLV model built hitherto exclusively on observations from in vitro grown viruses.

Animals↗
PubMed1980

[Kinetics of the propagation of a murine virus (C57Bl mice) in the lymphoid system and bone marrow of rats (study using electron microscopy)].

Either a Slow (SL) or Early (EL) type of leukemia are respectively induced in rats by the RadLV-Rs derived BL/F (SL) and BL/F (EL) viral populations. The kinetics of virus propagation was studied comparatively in the thymus, spleen, lymph nodes and bone marrow of rats infected either with BL/F (EL) or BL/F (SL). During the first days after inoculation with BL/F (SL), the viral population increased rapidly in all tissues, reaching a peak at day 8 to 10, except in the lymph nodes which were almost devoid of viral particles. A very different pattern was shown by the EL leukemia, indicating the importance of the early distribution of viruses amongst the lymphoid tissues in view of the further development of the disease. The large amount of viruses observed inside the megakaryocytes and budding from these cells confirm that they play a role in the leukemogenesis.

Animals↗
PubMed1978

Characterization by molecular hybridization of two viral populations derived from a radiation leukemia virus.

Two leukemogenic viral populations were derived from a radiation leukemia virus of the C57BL mouse. One (FB), in which only B-tropic virus could be detected, was obtained in vivo by serial passage of cell-free extract in newborn rats. The second (3C), a complex containing at least B-tropic and xenotropic viruses, was produced in vitro by a permanent cell line (13-3C) established from the spleen of a virus-infected C57BL mouse. In molecular hybridization experiments, the 70S RNA of Gross leukemia virus hybridized 96 and 78% of FB and 3C radioactive complementary DNA's, respectively, with a relatively high thermal stability of the duplexes formed. In contrast, the 70S RNA of Rauscher leukemia virus hybridized 23 and 20% of the FB and 3C DNA probes, respectively, with a low thermal stability. The rat-grown FB virions exhibited 50% genome homology with the viruses produced in vitro on the 13-3C cells. Finally, hybridizing the FB and 3C probes with normal or leukemic mouse spleen DNA's resulted in 89 to 100% homology. The rat-grown virions did not appear to contain detectable rat cellular DNA sequences, while about 20 complete copies of their nucleotide sequences were detected in covalent linkage with FB-infected rat spleen DNA. These findings strongly support the endogenous murine origin of the investigated virions.

AKR murine leukemia virus↗