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Biomedical subjects

Y Chardonnet

Publications and source records attributed to Y Chardonnet.

At least 109 records · Page 6Linked to original sources
PubMed1977

The fate of type 7 adenovirions in lysosomes of HeLa cells.

Properties of type 7 adenovirions in lysosomes of HeLa cells were studied 12 hr postinfection. Viral particles were transferred to the lysosomes very quickly after initiation of penetration, i.e., after 10 min of incubation at 37 degrees. No morphological modification of the virion was detected for 6 hr postinfection. However, by 12 hr postinfection, the virion was no longer recognizable. Most of the virus remained infectious for 2 hr, whereas after 12 hr the infectivity was abolished. Soon after the adsorption of the virus on the cell membrane at 4 degrees, the viral DNA in the virion became sensitive to pancreatic DNase, and this sensitivity increased during the first 2 hr of incubation at 37 degrees. This result suggests that some modification in the architecture of the virion occurred before transfer to the lysosomes. The adenovirus 7 (Ad 7) DNA extracted from the lysosomes appeared intact for 6 hr postinfection and was found to cosediment at 34 S with the Ad 2 DNA marker. Comparable activities of free acid phosphatase were found in lysosomes isolated from uninfected control cells and from infected cells. In in vitro experiments, lysosomal acid DNase and pancreatic DNase were shown to degrade Ad 7 DNA at similar rates; however, in vivo, intralysosomal Ad 7 DNA was only partially sensitive to lysosomal DNase.

Acid Phosphatase↗
PubMed1977

Integrated viral sequences in adenovirus type 12-transformed hamster cells.

The physical state of the viral genome in four lines of hamster cells transformed by adenovirus type 12 (Ad12) has been investigated. The four lines of transformed cells originated from hamster cells after infection with Ad12 at multiplicities ranging from 5-350 plaque-forming units per cell. The DNA from transformed cells has been restricted with the Sal I endonuclease from Streptomyces albus which cleaves adenovirus DNA more frequently than DNA from adenovirus-transformed hamster cells. Thus after cleavage by the Sal I enzyme, it is possible to separate free adenovirus DNA sequences from these which are covalently linked to cellular DNA in transformed hamster cells. The results of sequential hybridization experiments in which the Sal I-treated DNA from transformed cells is first annealed to Ad12 DNA on filters, then eluted, and finally hybridized to hamster cell DNA, support the model of Ad12 DNA integrated in multiple fragments into the host genome. Further experiments will be required to characterize the host sequences adjacent to adenovirus DNA and to compare these sequences in different lines of Ad12 transformed cells.

Adenoviridae↗
PubMed1977

Specific immunity in patients suffering from recurring warts before and after repetitive intradermal tests with human papilloma virus.

The specific humoral and cellular immunity of 22 patients with multiple or recurring warts was studied. After repeated intradermal tests, using an inactivated, purified viral antigen, the responses obtained could be classed into two groups. The first group (10 patients) was characterized immunologically by the acquisition of a specific cellular immunity and the appearance of circulating IgG antibodies, and clinically by a total regression of resolution of the warts two to three weeks after the final intradermal test. The second group (12 patients) was characterized immunologically by a weak or non-existent specific immune response, and clinically by the unmodified persistence of the warts.

Adult↗
PubMed1977

[Culture of cells isolated from the smooth muscle of the rat duodenum].

A culture obtained from rat duodenal smooth muscle layer is described. The cells are isolated by trypsinization (0.2 %) and the medium used for culture is either MEM with glutamine and non essentiel AA, or RPMI, both containing 10 % foetal calf serum. The cell culture contains both smooth muscle cells and fibroblasts in proportions varying with the age of the culture. At day 6, cell differenciation is important. At day 12, when the cells and confluent, the majority of the cells are fibroblasts. Although it is difficult, the transfer of cells is possible at least twice.

Animals↗
PubMed1977

An in vivo study of cell-mediated immunity in human warts. Preliminary results.

Purified human papilloma virus (HPV) was used to study cell-mediated immunity (CMI) in patients with warts and in controls by means of the intradermal test (IDT). IDT was positive in 75% of patients with past history of warts, in 56% of patients presenting with warts, but in only 7% of controls. Immunofluorescent antibody levels were initially low and increased after injection of HPV antigen in all groups.

Antibodies, Viral↗
PubMed1976

[Transfer of adenovirus DNA into the nucleus at the beginning of infection of HeLa cells].

2 hrs after infection of HeLa cells with Ad 7, viral DNA was found in the nuclei. Inactivation of the virus with ultraviolet or antiserum, or pretreatment of the cells with chloroquine, did not affect the localisation of the DNA. The intranuclear DNA originated at least partly from viral particles passing through lysosomes. The appearance of Ad 7 DNA in the nucleus was delayed as compared to Ad 5 DNA.

Adenoviridae↗
PubMed1976

[Effects of colchicine, vinblastine and mercury p-hydroxybenzoate on the multiplication of adenovirus 5 in HeLa cells].

After 30 min incubation at 37 with 10(-4) M PHMB (p-hydroxymercuribenzoate), monolayers of HeLa cells are not affected; after 3 h exposure to 10(-5) M colchicin or 2.5 X 10(-5) M vinblastine, HeLa cells are not altered morphologically but the number of cells is decreasing between 1 and 2 days post treatment. When cells are kept in suspension after trypsinization, their ability to adhere to the Petri dishes is not altered with 10(-4) M PHMB but only 50% of the cells are able to attach after treatment with colchicine or vinblastine. Adenovirus type 5 is unsensitive to the effect of colchicine and vinblastine at various concentrations, after 3 h incubation at 37. With 10(-3) M PHMB, the virus is inactivated, infectivity and hemagglutinating activity are almost abolished but the particles are unsensitive to pancreatic DNase, so that the structure of the viral particle is intact. This effect is reduced with 10(-4) M PHMB. The adenovirus 5 multiplication is not affected when HeLa cells are treated with 10(-5) M colchicine or 2.5 X 10(-5) M vinblastine, before and during adsorption of the virus. The viral production decreases after 24 h treatment with colchicine or vinblastine. Treatment with 10(-4) M PHMB does not influence intra- or extracellular viral yield.

Adenoviridae↗
PubMed1975

[Immunofluorescence study of the migration of adenovirus 5 in HeLa cell cytoplasm during the penetration phase].

Using the indirect immunofluorescence technique in presence of anti-adenovirus-5 antibody, fluorescent spots were observed two hours after adsorption at 4 degrees C onto HeLa cells on the surface of the cells. The spots subsequently became intracytoplasmic and persisted about 7 to 8 h. Intense fluorescence was further observed in the whole cytoplasm and in the nucleus 12 h following the injection.

Adenoviridae↗
PubMed1974

Persistence of Adenovirus 5 in guinea pigs.

One intracardiac inoculation of adenovirus 5 in guinea pigs leads to virus persistence in different organs, viz., 5 days in lungs and liver, 14 days in blood and lymph nodes, and 56 days or more in the spleen. After cultivation of tissue cells for 1 week, virus was recovered from blood, lymph nodes, or spleen lymphocytes, but virus could be detected directly in cells only when organs were removed within 48 h of inoculation. To determine how the virus persisted in low concentrations and as a latent infection, spleens were primarily selected for study by three techniques: homogenization of spleens, suspended Maitland fragment cultures, and in vitro cultivation of spleen cells. The last procedure showed virus in fibroblast-like cells (probably macrophages or reticuloendothelial cells) for 56 days after infection of guinea pigs. With other methods, the virus was found only within the first 2 days after inoculation.

Adenoviridae↗