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P Markovits

Publications and source records attributed to P Markovits.

At least 19 recordsLinked to original sources
PubMed1986

Virus isolation from and identification of HTLV-III/LAV-producing cells in brain tissue from a patient with AIDS.

Primary cultures from a brain biopsy specimen of a human T-cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) seropositive patient with progressive dementia contained small numbers of monocytoid cells and showed reverse transcriptase activity that persisted for as long as 100 days. Electron microscopy of these cells revealed the presence of HTLV-III/LAV virions. Subcultured cells removed from primary cultures by trypsinization were nonspecific esterase negative and did not express virus or show evidence of HTLV-III/LAV proviral sequences, while those remaining in the original flasks were nonspecific esterase positive and continued to produce virus. Virus from primary cultures was transmitted to peripheral blood-derived monocyte-macrophages and T cells. Virus production in T-cell cultures was transient while the monocyte-macrophages, like the primary cultures, produced virus for at least 120 days. Infection of several brain-derived cells with this and another HTLV-III/LAV isolate failed to demonstrate virus replication. These results indicate that the HTLV-III/LAV-infected cells recovered from the brain of this patient are cells of the mononuclear phagocyte series.

Acquired Immunodeficiency Syndrome↗
PubMed1986

The role of mononuclear phagocytes in HTLV-III/LAV infection.

Cells with properties characteristic of mononuclear phagocytes were evaluated for infectivity with five different isolates of the AIDS virus, HTLV-III/LAV. Mononuclear phagocytes cultured from brain and lung tissues of AIDS patients harbored the virus. In vitro-infected macrophages from the peripheral blood, bone marrow, or cord blood of healthy donors produced large quantities of virus. Virus production persisted for at least 40 days and was not dependent on host cell proliferation. Giant multinucleated cells were frequently observed in the macrophage cultures and numerous virus particles, often located within vacuole-like structures, were present in infected cells. The different virus isolates were compared for their ability to infect macrophages and T cells. Isolates from lung- and brain-derived macrophages had a significantly higher ability to infect macrophages than T cells. In contrast, the prototype HTLV-III beta showed a 10,000-fold lower ability to infect macrophages than T cells and virus production was one-tenth that in macrophage cultures infected with other isolates, indicating that a particular variant of HTLV-III/LAV may have a preferential tropism for macrophages or T cells. These results suggest that mononuclear phagocytes may serve as primary targets for infection and agents for virus dissemination and that these virus-infected cells may play a role in the pathogenesis of the disease.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Effects of in vitro infection of mouse glial and neuroblastoma cells with the scrapie agent.

Mouse glial and neuroblastoma cells were infected with the mouse adapted strains C506 and 139A of scrapie agent. Lysates of the in vitro infected cells (from the 3rd to the 16th passage) intracerebrally inoculated into CD-1 mice, caused the development of a neurological disease, with characteristic signs of scrapie. Morphological changes in scrapie-infected neural cells were observed after about fifteen in vitro passages. In liquid medium, the cloning efficiency of these cells increased. They acquired the capacity to form large tridimensional colonies in agar. Heating the infectious brain extracts at 60 and 80 degrees C for 30 minutes did not inhibit these changes thus showing the involvement of the thermoresistant scrapie agent. Supernatants of scrapie-infected glial cells promoted colony formation in liquid medium with different types of normal cells. Analysis of supernatants of scrapie-infected mouse neuroblastoma cells showed a profound modification of neurotransmitter metabolism.

Animals↗
PubMed1983

In vitro propagation of the scrapie agent. I. Transformation of mouse glia and neuroblastoma cells after infection with the mouse-adapted scrapie strain c-506.

Seven cell lines including glia cells from mouse brains and mouse neuroblastoma cells were infected with the mouse-adapted scrapie strain c-506. During the early in vitro passages, a stimulation of growth was already observed but cellular morphology and differentiation did not alter. Later on, after 12-16 passages, six of the seven infected lines displayed cell proliferation and morphological alterations, suggesting an in vitro morphological transformation. At this stage, differentiation was no longer observed in the scrapie-infected neuroblastoma cells and all the scrapie-infected cells formed two to four times more colonies in liquid medium than the controls, and developed large tridimensional colonies in agar. The part played by the scrapie agent in these changes is discussed.

Animals↗
PubMed1982

[In vitro modification of the morphology and the growth of cells infected with scrapie (author's transl)].

Seven cell lines originated either in brains or in neuroblastomas of Mice, were infected with Scrapie. After 12 to 16 in vitro passages, 6 lines out of 7 showed changes of their morphology, and of their growth, resembling those occurring in the course of a malignant transformation. The Scrapie infected cells acquired the capacity to form 2 to 4 times more colonies in liquid medium than the controls, and to develop large tridimensional colonies in semisolid medium. The role of Scrapie in these changes is discussed.

Animals↗
PubMed1981

[Trials of in vitro propagation of the scrapie agent in mouse nerve cells].

We attempted to propagate the Scrapie agent in vitro in glia and neuroblastoma cells of Mice. Four out of seven assays of infection were positive, i.e. after several passages in vitro yielding at most a 10(9) fold final dilution of the original material, the extracts of each of the four cultures, when injected intracerebrally into CD1 Mice, produced a deadly disease displaying the clinical and pathological signs characteristic of Scrapie.

Animals↗
PubMed1981

Metabolism of benzo[a]pyrene by brain microsomes of fetal and adult rats and mice. Induction by 5,6 benzoflavone, comparison with liver and lung microsomal activities.

Using brain, lung and liver microsomes as the enzyme source in in vitro assays, benzo[a]pyrene (B[a]P) metabolism was studied in fetuses and dams of mice (C57B1/6) and rats (WAG). Separation and quantitation of B[a]P metabolites were performed by h.p.l.c. Microsomal preparations were tested for cytochrome P-450 dependent O-dealkylation of 7-ethoxycoumarin and epoxide hydrolase activities. Another parameter measured included the conjugation of 1-chloro-2,4 dinitrobenzene to glutathione by cytosolic glutathione-S-transferase activity. The induction of B[a]P metabolism was studied after treatment of animals with 5,6-benzoflavone (BF). Mixed function oxygenase, epoxide hydrolase and glutathione-S-transferase activities were transplacentally inducible after dams were treated with BF. Metabolic activation of B[a]P by fetal brain microsomes was lower in both species than that by fetal lung and liver microsomes, but it was higher in fetuses than in adults. All metabolites of B[a]P increased after BF treatment; the production of 7,8-dihydro-7,8-dihydroxybenzo[a]pyrene (7,8-dihydrodiol B[a]P) was higher in brain microsomes from BF-treated rats than that in mice. In stimulated rats, the formation of 7,8-dihydrodiol B[a]P by fetal brain microsomes were higher than that by fetal lung microsomes, whereas in mice, the opposite was observed. These data suggest that initiation could occur in utero, and partially explain the species-specific differences in susceptibility to transplacental tumorigenesis by polycyclic aromatic hydrocarbons by differences in biotransformation in the target organ.

Animals↗
PubMed1979

[In vitro malignant transformation of hamster lung cells by 2-chlorobutadiene].

Normal Hamster lung cells from an established line were treated with 1-500 microgram . ml-1 2-chlorobutadiene. Those treated with 1 microgram . ml-1 of the compound showed malignant transformations 14 weeks after treatment. The treatment with higher concentrations did not accelerate the transformation process.

Animals↗
PubMed1979

Normal and benzo(a)pyrene-transformed fetal mouse brain cell. I. Tumorigenicity and immunochemical detection of glial fibrillary acidic protein.

Primary cultures of whole brain and cortex cells origination from 14-day-old A/Jax or C3H mouse fetuses were treated with benzo(a)pyrene (B(a)P) for 24 h. After 7 to 8 passages a malignant transformation was observed in the chemically treated whole brain and cortex cultures. Control cultures of cortex remained non-transplantable during the whole experiment (up to 14 passages) whereas in the control cultures originating from whole brain a spontaneous transformation appeared after 11 passages. With horseradish peroxidase-labelled antibody, the specific glial fibrillary acidic protein (GFAP) was detected in both control and transformed total brain and cortex cultures, and in the tumors initiated by the in vitro transformed cells. This finding shows that glialike cells persisted after a long in vitro maintanance and transformation.

Animals↗
PubMed1979

Normal and benzo(a)pyrene-transformed fetal mouse brain cells. II. Ultrastructural study.

An ultrastructural study was performed on normal and Benzo(a)-pyrene(B(a)P)-transformed fetal mouse brain cells. Early subcultures of a strain initiated from whole brain presented three cell types in vitro: astroglial, poorly differentiated glial, and spongioblastic types. After B(a)P-treatment, there was an exclusive transformation and the growth of neuroglia sometimes without gliofibrillary maturation, but with the presence of glial fibrillary acidic protein (GFAP) in the cytoplasm. Early subcultures of another strain initiated from cortex only presented poorly differentiated neuroglial cells. After transformation, cell maturation as evidenced by gliofibrillogenesis and GFAP production by these cells was observed. In both cases, the potentiality of glial differentiation after in vitro malignant transformation by a chemical carcinogen seemed preserved.

Animals↗
PubMed1979

Lymphography in childhood rhabdomyosarcomas.

Forty-one children with subdiaphragmatic rhabdomyosarcoma underwent bipedal lymphography. Twenty-two (53.5%) of the lymphograms were interpreted as being positive. In our series, the lower limbs were the most common primary site of involvement, were more frequently involved by the alveolar histologic subtype which carries a poor prognosis, and were associated with a higher incidence of lymph node metastases. Positive lymphographic findings in this group of children were similar to those seen in both adults and children with other solid tumors, i.e., the presence of discrete lymph node filling defects. However, in 3 cases, abnormalities more characteristic of lymphoma were identified. Evaluation of lymph node metastases as demonstrated by lymphography has prognostic significance.

Abdominal Neoplasms↗
PubMed1979

[Spontaneous transformation and long term culture of foetal mouse glial cells (author's transl)].

Six cell lines originated from foetal mouse brain were maintained in vitro for more than two years. The morphology of most of these cultures suggests their glial character. This is corroborated, for some lines, by the presence of specific glial protein (Glial fibrillary acidic protein, or GFAP). Five out of these lines remained not transplantable in animals during all the experiments. However one of them went through a spontaneous transformation at the eleventh population doubling. This culture, after transformation remained glial and when injected in animals, induced GFAP containing tumors.

Animals↗
PubMed1977

[In vitro malignant transformation of fetal hamster brain cells by methylnitrosourea].

Using primary cultures originating from 14 day old fetal Hamster brain, we have obtained a cell line with glial morphology. These cell remain non transplantable during the first year of in vitro culture, but undergo spontaneous transformation during the second year. Following prolonged contact of the glial-like cells with 25 to 50 microgram/ml of methylnitrosourea (MNU), a malignant transformation is observed 5 months after the treatment. The lowest concentrations of (MNU) do not cause malignant transformation, but seem to inhibit (or postpone) the spontaneous transformation. After MNU treatment, cells retain their glial nature.

Animals↗
PubMed1977

Experiment with 659 consecutive lymphograms in children.

Between 1963 and January 30, 1975, 659 children under 16 years of age were referred for bipedal lymphography at the Institut Gustave-Roussy. Approximately one-third were under 5 years of age. The vast majority had documented malignant disease. Successful bilateral lymphatic cannulation and lymph nodd opacification were accomplished in 86.7% of all children. Another 11.6% had successful unilateral lymphograms, which usually provided sufficient information to be considered as diagnostic stldies. In only 1.7% of all children was the study unsuccessful bilaterally. Lymphatic cannulation failure rates progressively decreased as the child increased in age. There were five "allergic" reactions (0.75%), one of which was considered life-threatening, and one instance (0.15%) of a transient neurological deficit. No permanent sequelae or deaths were attributed to the lymphogram.

Adolescent↗
PubMed1977

Hamster cells, untreated and treated with chemical carcinogens, maintained in vitro for 2 1/2 years.

We have maintained in culture, for a prolonged period, untreated hamster cells from whole embryo, foetal brain and lung from newborn animals. Among the 7 lines studied we observed only one spontaneous transformation during the first year of culture. The cells of the 6 other control lines remained normal and diploid, and were not transplantable during the first 9 to 12 months of culture. After the 12th month, changes appeared in their in vitro behaviour and their transplantability: grafts of 0-5-2 X 10(6) cells induced tumours in the hamster; fewer cells did not. In vitro chemically transformed hamster cells were fundamentally different from untreated cells of the same origin, not only in morphological and growth characteristics but also in transplantability; of the 9 lines obtained, 7 induced tumours after injection of 10(1)-10(4) cells, and 2 after injection of 10(5) cells per animal.

9,10-Dimethyl-1,2-benzanthracene↗