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Biomedical subjects

F Golais

Publications and source records attributed to F Golais.

18 recordsLinked to original sources
PubMed1999

Enhanced proliferation and progesterone production by porcine granulosa cells cultured with pseudorabies virus growth factor (PRGF).

The objective of this research was to study possible interactions of pseudorabies virus growth factor (PRGF) with ovarian tissue. Granulosa cells isolated from porcine ovaries were cultured as monolayers for 6 days in a control medium without PRGF and in medium supplemented with different doses of this agent. Increased population density and change towards more fibroblastic-like shape of cells cultured with 10(9) I.U PRGF was observed when compared with control culture. The cells divided significantly faster during 6 days of culture under the influence of 10(3), 10(4), 10(5), 10(6), 10(7), 10(8) and 10(9) I.U./ml of PRGF at a dose dependent manner. PRGF in a dose 10(9) I.U. added to cultured cells isolated from small and medium follicles did not influence progesterone secretion . An increase of progesterone secretion under the influence of PRGF in all investigated days of cultures was observed in cells isolated from large preovulatory follicles. The marked increase in progesterone content in PRGF treated culture in doses of 0.5x10(7), 0.5x10(8), 0.5x10(9) I.U. was observed during 4 and 6 days of culture. The rise of progesterone content was not connected with increased number of secretory cells, but with a stimulation of production per cell. PRGF exerted no visible effect on progesterone secretion by granulosa cells from small and medium follicles cultured for 6 days. The presented in vitro data provide evidence for a local action of PRGF in the follicle depending on the stage of follicular development and duration of exposure. Precise relevance of the interaction of PRGF with follicular development requires further study.

Animals↗
PubMed1999

Dual effect of pseudorabies virus growth factor (PRGF) displayed on actin cytoskeleton.

Pseudorabies virus growth factor (PRGF) was shown to possess transforming activity as well as transformation repressing activity in in vitro systems. In order to better understand these phenomena we studied actin cytoskeleton and its alterations induced by PRGF using normal human fibroblasts VH-10 and transformed cell line HeLa. For specific detection of filamentous actin cells were stained with phalloidin conjugated with fluorescein isothiocyanate (FITC)-phalloidin. PRGF was applied to VH-10 cells for various length of time from 10 min up to 48 h. The effect was very fast and changes in actin filament composition could be detected already after 10 min. In comparison to untreated cells the staining of treated cells was more diffuse and a number of actin microfilaments in individual stress fibers became reduced. After 30 min thick short actin bundles appeared in the perinuclear region. A 24-h exposure resulted in a large reduction of actin bundles. After additional 24 h a partial restoration of actin cytoskeleton in cells was observed. In transformed HeLa cells PRGF induced opposite process than in normal cells: the number of filamentous actin structures increased. We hypothesise that PRGF may act as a transcription-like factor and may initiate changes in gene expression which consequently result in actin cytoskeleton alterations.

Actins↗
PubMed1994

Morphological transformation of Syrian hamster embryo cells by pseudorabies virus related growth factor.

Syrian hamster embryo (SHE) clonal morphological transformation assay has been used for the in vitro testing of transforming activity of Pseudorabies virus (PRV) related growth factor (PRGF). It was found that PRGF induces morphologically transformed colonies of SHE cells in the wide titer scale (in the range 1 x 10(7) to 1 x 10(13) U/ml). The concentrations of PRGF which induced the transforming phenotype of SHE cells in the colonies did not cause significant cytotoxic effect.

Animals↗
PubMed1994

Pseudorabies virus growth factor can be resolved into two active components.

Pseudorabies virus (PRV) growth factor (PRGF) which induces a transformed phenotype in normal MK-2 cells and represses the transformed phenotype of Hela cells was partially purified and resolved into two components (M(r) < 300 and < 180). Each of the PRGF components retained the transforming activity of the original factor in MK-2 cells but lost its transformation-repressing activity in Hela cells. The latter activity of PRGF could be reconstituted by simultaneous application of its two components. Two monoclonal antibodies against gII glycoprotein of PRV were able to neutralize both PRGF activities, thus supporting the previously suggested hypothesis that the PRV gene for glycoprotein gII might be involved in PRGF synthesis.

Animals↗
PubMed1992

Herpes simplex virus type 2 and pseudorabies virus associated growth factors and their role in the latency in vitro.

A putative herpes simplex virus type 2 (HSV-2) growth factor (HSGF-2) was detected in a crude extract from virus infected mouse embryo cells. This factor, similar to previously described pseudorabies virus (PRV) associated growth factor (PRGF) was shown to have ability to morphologically transform non-transformed cells and to repress the transformed phenotype of transformed cells. Both activities could be neutralized with two, out of seven monoclonal antibodies directed against glycoprotein B of HSV-2. Both PRGF and HSGF-2 were detected in human embryo lung cells latently infected with PRV or HSV-2 either at 41 degrees C, or in the presence of phosphonoacetic acid. Human alpha-2 interferon, when present in medium of latently infected cells enhanced the production of both HSGF and PRGF. On the contrary, when latently infected cells were treated with 5-azacytidine the synthesis of both PRGF and HSGF-2 was completely blocked and the virus reactivated from latency replicated to higher titers than in non-treated cells. The role of PRGF and HSGF-2 in the establishment, maintenance and reactivation of latency, as well as in cellular transformation is discussed.

Animals↗
PubMed1992

Some physicochemical properties of murine herpes virus.

The effect of incubation temperature variation and various pH values on the stability of murine herpesvirus isolate-76 (MHV-76) was investigated. The virus survival in rabbit embryo fibroblasts cells (REF) has been determined. At room temperature (23 degrees C) 50% of the virus became inactivated during 12 days and at 37 degrees C its half life was 9 days. MHV-76 was completely inactivated at 50 degrees C in 1 hr or at 41 degrees C in 7 hrs. MHV-76 retains its maximal infectivity at the pH range between 6-9 regardless of the duration of treatment. The pH range 3, 4, 5 and 10, 11, 12 caused either complete or more or less expressed inactivation of the virus. A complete inactivation MHV-76 was also achieved after treatment with ethyl ether, chloroform and 2M urea.

Animals↗
PubMed1992

The glycoprotein B gene and its syn3 locus of herpes simplex virus type 1 are involved in the synthesis of virus-associated growth factor (HSGF-1).

A putative growth factor (HSGF-1) associated with herpes simplex virus type 1 (HSV-1), which is similar to PRGF associated with pseudorabies virus, and/or HSGF-2 associated with HSV-2, was described. Experiments with four syncytial (syn) and four nonsyncytial (syn+) HSV-1 strains showed that the ability of this virus to produce HSGF-1 in infected cells is associated with the syn+ phenotype. Double infection of cells with syn+ and syn strain resulted either in enhancement or complete inhibition of HSGF-1 production, depending on the chosen pair of syn+ and syn strains. The studies with the recombinants between the syn+ strain KOS and syn strain ANGpath in the gene for glycoprotein B (gB) and syn3 locus revealed that the gB gene and its syn3 locus play a role in the HSGF-1 synthesis.

Animals↗
PubMed1988

Transforming activity of crude extract of pseudorabies virus-transformed cells.

Crude extract of pseudorabies virus (PRV)-transformed human (H-PR-1) cells induced transformation in human embryonic lung (HEL) cells. When the extract was removed, the acquired cell morphology remained unchanged, but the saturation density of cells was decreased. The transforming effect of the extract was neutralized with anti-PRV IgG.

Cell Transformation, Viral↗
PubMed1980

New model cell systems (PK and XTC-2) for studying acute and persistent infections with herpes simplex and pseudorabies viruses.

Herpes simplex virus type 1 (HSV-1) showed limited replication in PK (pig kidney) and XTC-2 (Xenopus laevis frog) cell lines. Virus replication depended on the multiplicity of infection (MOI). At a high MOI, HSV-1 caused a typical cytopathic effect (CPE) in XTC-2 cells but a little marked CPE in PK cells. Pseudorabies virus (PRV) replicated intensively in PK cells (permissive system) but not in XTC-2 cells (nonpermissive system). Both viruses were adsorbed on to PK and XTC-2 cells. In infected PK cells, fluorescent HSV-1 antigen was demonstrated only in the vicinity of the nuclear membrane and in the paranuclear area of the cytoplasm but not in the nuclei. In XTC-2 cells, HSV-1 antigen was demonstrated also in the nuclei. Persistent HSV-1 infection was induced in PK but not in XTC-2 cells; it was of limited duration. PK cells which had lost HSV-1 multiplied further and proved susceptible to infection with HSV-1 or PRV.

Animals↗
PubMed1979

The effect of antibody on latent pseudorabies virus infection in vitro.

Cytosine arabinoside (Ara C) inhibited the synthesis of pseudorabies virus when Vero cells were infected at a multiplicity of infection of 0.0001-0.05 PFU per cell. On removal of Ara C, infectious virus reappeared after a latent period of 3-5 days. The activation of latent virus was not influenced by elevating the temperature to 40 degrees C at the time of Ara C removal but it was prevented by antiviral antibody. When antiviral IgG was added into the culture fluid of cells either during the incubation with Ara C, or after removal of the inhibitor, the number of infectious centres was reduced to about 10%. The role of antiviral IgG in the maintenance of latency is discussed.

Animals↗
PubMed1978

Latent pseudorabies virus infection established at supraoptimal temperature.

Little or no infectious virus was recovered from BHK-21 cells adapted to 40 degrees C, when they were infected with an attenuated strain of pseudorabies virus (PRV) at low multiplicity of infection (MOI) and subsequently kept at 40 degrees C. By passaging the infected cells at 40 degrees C, infectious virus disappeared within 2-3 passages. When the cells were shifted down to 37 degrees C, activation of virus growth occurred after a latent period of 48-72 hr. Infected cells kept at 40 degrees C were as sensitive to superinfection with the virulent PRV strain TOP as the control cells. The ability of PRV strains to enter into the described latent state was related with the degree of their virulence. When cells were treated with 5-bromo-2-deoxyuridine (BUdR) at 40 degrees C for 24 hr and then shifted to 37 degrees C, a slight increase in the number of infectious centres was observed and the latent period was also prolonged.

Animals↗
PubMed1977

Susceptibility of various cell lines to virulent an attenuated strains of pseudorabies virus at supraoptimal temperature.

Replication of virulent and attenuated strains of pseudorabies virus (PRV) at supraoptimal temperature was studied in rabbit lung (ZP), pig kidney (PS), and BHK-21 cells adapted and non-adapted to 40 degrees C and L, HeLa and human amniotic (Am) cells non-adapted to 40 degrees C. The temperature of 40 degreeC did not influence the type cytopathic effect (CPE) in either adapted or non-adapted cells. According to the susceptibility at 40 degrees C the cells could be divided into three groups: cells permissive for all PRV strains (adapted and non-adapted ZP and non-adapted BHK-21 and PS); cells non-permissive for all PRV strains (L, HeLa and Am); and cells permissive for virulent and non-permissive for attenuated PRV strains (adapted BHK-21 and PS). The virus titres in permissive cells at 40 degrees C did not differ from those obtained at 37 degrees C. The attenuated strain CK-PRV X was found to be a tsmutant of PRV with host range character.

Cell Line↗
PubMed1977

The effect of supraoptimal temperature on the formation of pseudorabies virus particles.

Replication of virulent and attenuated strains of pseudorabies virus (PRV) at supraoptimal temperature was inhibited in L cells non-adapted to 40 degrees C. Electron microscopy revealed the prevalence of hollow core particles without nucleoid; both the nuclei and cytoplasm of L cells were markedly altered at supraoptimal temperature. In BHK-21 cells adapted to 40 degrees C only replication of attenuated strains was inhibited whereas the virulent ones reached high titres at this temperature. The particles produced at 40 degrees C by attenuated strains were non-infectious but morphologically normal. The ability of attenuated PRV strains to reproduce in adapted BHK-21 cells at 40 degrees C was in correlation with the degree of their attenuation. Changes in the nuclei and cytoplasm of adapted BHK-21 cells at supraoptimal temperature were not as marked as in L cells.

Animals↗
PubMed1976

Susceptibility of various cell lines to virulent and attenuated strains of pseudorabies virus.

Various cell lines were infected with virulent and attenuated strains of pseudorabies virus (PRV). According to the type of the cytopathic effect (CPE), the cells could be divided into 3 groups: cells in which all strains formed syncytia; cells in which all strains caused rounding of cells; and cells in which virulent strains caused syncytium formation while attenuated ones rounding of cells. Neither the form (fibroblastoid or epithelial) nor the origin of cells influenced the type of the CPE. L cells and some cell lines derived from human tissue proved to be less sensitive to PRV than other cells. In certain human cells (e.g. HeLa and D6) virulent PRV strains propagated better than attenuated ones.

Cell Line↗
PubMed1976

Infection of Hela cells with a virulent and an attenuated strain of pseudorabies virus studied by electron microscopy.

Hollow-core particles, forming crystals in nuclei, prevailed in HeLa cells infected with an attenuated strain of pseudorabies virus (PRV). After infection with a virulent PRV strain, the cells contained mainly fully infectious dense-core particles. These findings might explain the lower susceptibility of HeLa and some other human cells to infection with attenuated strains of PRV as compared to virulent strains.

Cell Nucleus↗
PubMed1975

The effect of temperature and urea on virulent and attenuated strains of pseudoabies virus.

Out of 10 virulent strains of pseudorabies virus (PRV), 9 proved to be resistant and 3 out of 4 attenuated strains were sensitive to the temperature of 53 degrees C. No differences were found between attenuated and virulent strains of PRV in their rate of inactivation of 2 M urea; its inactivating effect was enhanced by increasing the temperature. The t (effect of temperature) and u (effect of urea) markers proved unsuitable for a sufficient characterization of PRV strains.

Genes↗