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Biomedical subjects

R Deloince

Publications and source records attributed to R Deloince.

35 records · Page 2Linked to original sources
PubMed1987

Continuous production of hepatitis A virus in PLC/PRF/5 cell cultures: use of antigen for serology.

The strain CF53 of hepatitis A virus (HAV) previously adapted to growth in PLC/PRF/5 cells was grown in 175 cm2 flasks, at different passages. After infection, cells were incubated at 32 degrees C in RPMI 1640 medium supplemented with 2.5% foetal calf serum (FCS) for 6-12 months. HAV which was released continuously in the culture medium was harvested weekly. Hepatitis A virus antigen (HAAg) and infectious virus production was stable during each passage. The antigen titre, determined by radioimmunoassay, was about 50 for each passage whereas the infectious virus titre increased from 10(3.7) (passage 7) to 10(6.0) TCID50/ml (passage 13). Virus production was not influenced by the FCS concentration (0-2.5%) in the maintenance medium. The cell culture produced HAAg was used for detection of total anti-HAV antibodies, anti-HAV titration and IgM antibody capture assay and the results were identical to those obtained with commercial kits. HAAg produced by this practical and cheap method could easily replace primate derived antigen for the detection of anti-HAV antibodies.

Antibodies, Viral↗
PubMed1985

[Adaptation to the cell line PLC/PRF/5 of hepatitis A virus released in the cell culture medium].

The propagation of hepatitis A virus (HAV), CF53 strain, released without any cytopathic effect into the PLC/PRF/5 cells supernatant, was studied in the course of six serial passages (6th to 11th). The decrease (from 5 to 1 week) of incubation time required to detect HAV, by RIA, in culture supernatant, the increase in Hepatitis A antigen (from 777 to 10,038 c.p.m./50 microliter) and infectivity titre (from 10(3.0) TCID 50/ml to 10(4.5) TCID 50/ml) were consistent with the adaptation of this virus to the cell line PLC/PRF/5.

Carcinoma, Hepatocellular↗
PubMed1983

[Release of hepatitis A virus into the culture medium, during its replication in PLC/PRF/5 cells].

Hepatitis A virus (HAV), obtained from human feces collected 3 days after the onset of jaundice, was propagated in human hepatocarcinoma cells (PLC/PRF/5). In the course of 5 passages, it was released into the supernatant without cytopathic effect. Released HAV was propagated after inoculation into PLC/PRF/5 cells. Its biophysical properties (buoyant density in CsCl: 1, 33 g/cm3; sedimentation coefficient: 155 S) were similar to those of the infectious particle present in the cells or in the stools of patients.

Carcinoma, Hepatocellular↗
PubMed1981

[Purification of hepatitis A virus from human feces].

Hepatitis A virus was purified from on early acute phase human stool by a procedure using 10% polyethylene glycol precipitation, sepharose 2B gel filtration, isopycnic banding in cesium chloride, rate zonal separation in sucrose - 99,5% of the 280 nm absorbing fecal impurities were removed.

Centrifugation, Density Gradient↗
PubMed1977

[Early effect of poliomyelitis virus on 5'-nucleotidase activity in HeLa cells].

One of the earlier effects of poliovirus was the maintaining of a high level of Hela cells 5'-nucleotidase activity (maximal efficiency for a virus/cell ratio = 500 ID 50/cell) (ID50:50% Infections Dose). The activity decreased when cells were suspended in the presence of EDTA(EDTA:Ethylene Diamine Tetracetic Acid) and was partially restored by adding 10 mM Mg++ interactions are discussed.

Edetic Acid↗
PubMed1977

[The effect of a mixture of bacterial ribosomes and membrane fractions of Klebsiella pneumoniae on the development of a transplanted epithelial cancer in rats].

An association of bacterial ribosomes and cell-wall of Klebsiella pneumoniae was shown to reduce the incidence of an epidermoid carcinoma in Sprague-Dawley rats when administered subcutaneously prior the tumoral graft. Mononuclear cells accumulate around the tumor. This association was considered as a non specific adjuvant stimulating the host's intrinsic immunity to tumor antigens.

Adjuvants, Immunologic↗
PubMedDate not supplied

Antiviral activity of carrageenan on hepatitis A virus replication in cell culture.

Sulphated polysaccharides such as iota-, lambda- and kappa-carrageenans showed a potent inhibitory effect on the replication of hepatitis A virus (HAV) in the human hepatoma cell line PLC/PRF/5. No cytotoxic effects were detected with concentrations of carrageenans up to 200 micrograms/ml. The selectivity indices of these substances, calculated as the ratio of the dose that reduced the number of viable cells to 50% (CD50) to the effective dose that inhibited 50% of viral antigen expression (ED50), were greater than 400 with iota-carrageenan, greater than 222 with lambda-carrageenan and greater than 10 with kappa-carrageenan. The selectivity index of ribavirin (reference substance) was only 5. The 3 types of carrageenans resulted in concentration-dependent reduction of HAV-antigen expression and HAV infectivity. lota-and lambda-carrageenan emerged, from the present study, as promising candidates for chemotherapy of acute hepatitis A.

Carrageenan↗
PubMedDate not supplied

[Histoenzymologic study of anticholinesterase activity of ciguatoxic extracts of Ceochetus striatus (Gunther) and Plectrompus leopardus].

The use of histo-enzymological techniques for visualizing the cholinesterasic spots on the motory plate is turned to account by the authors to point out the inhibition of the cholinesterasic processes, by some fractions of the ciguatoxins at the level of the neuro-mucular synapsis. The results obtained confirm, on one hand, the efficiency of the method to test the anti-cholinesterasic activity of some fractions of the ciguateric extracts, and, on the other hand, enable the establishment of the fact that even clinically non toxic individuals from fishspecies, dwelling in tropical coral biotops, can provoke a slightly marked but real inhibition of the cholinesterases, provided the contact between the fish extract and the neuro-motory plate is long enough in time. This observation reinforces the thesis of the ecological origin of the toxins along the alimentary chain of the reef biocoenosis.

Animals↗