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Biomedical subjects

V Vonka

Publications and source records attributed to V Vonka.

At least 109 records · Page 6Linked to original sources
PubMed1986

Cellular DNA synthesis associated with activation of latent herpes simplex virus in cell culture.

Herpes simplex virus type 1 (HSV-1) latency was established in human embryo lung (HEL) cells by treatment with (E)-5-(2'-bromovinyl)-2'-deoxyuridine and human leukocyte interferon and subsequent temperature increase (from 37 degrees to 40.5 degrees). This in vitro system was used to study reactivation after temperature shift-down to 37 degrees. Four methods known to induce cell DNA synthesis, superinfection with human cytomegalovirus, increased serum concentration in the medium, wound production, and superinfection with simian virus 40 (SV40), accelerated activation and replication of HSV-1. In contrast, reduced serum concentration resulted in postponement of virus reactivation and lower yield. In control experiments with mock-infected HEL cells treated with inhibitors and maintained for prolonged periods of time at 40.5 degrees, [3H]-thymidine incorporation was stimulated by increased serum concentration in the medium, wounding and SV40 superinfection, and hampered by reduced serum concentration in the medium. The data seem to indicate that cell DNA synthesis, the processes associated with it, or both, play a key role in the activation of latent HSV-1 and subsequent virus replication in this system.

Blood↗
PubMed1986

Demonstration of Epstein-Barr virus in malignant non-Hodgkin's lymphomas.

Lymph nodes or tumor biopsies of 60 persons suspected of having a malignant lymphoma were examined for the presence of Epstein-Barr virus nuclear antigen (EBNA) by anticomplement immunofluorescence. In 8 cases the tissue specimens were also assayed for Epstein-Barr virus (EBV) DNA by nucleic acid hybridization. Serum samples of patients and controls were tested for EBV-related antibodies. The histological tests in 37 cases showed a malignant non-Hodgkin lymphoma, and in 23 cases a reactive lymphadenopathy. A Burkitt lymphoma of a European boy and a polymorphic centroblastoma contained EBNA and approximately 27 or 30 genome equivalents EBV DNA per cell, respectively. EBNA was also demonstrated in about 20% of the cells of a lymph node from a patient with recurrent reactive lymphadenopathy.

Adolescent↗
PubMed1984

Prospective study on the relationship between cervical neoplasia and herpes simplex type-2 virus. I. Epidemiological characteristics.

To determine the risk associated with previous herpes simplex type-2 (HSV-2) infection and possibly other virus infections, a prospective study of cervical neoplasia in more than 10,000 women was performed in the 1975-1983 period. The subjects were selected at random from an alphabetical listing of eligible women living in one district of Prague. At enrollment colposcopy and cervical cytology were performed, a blood sample was taken and data regarding education, socio-economic status, personal habits and sexual and reproduction-associated attributes were obtained from each woman. A total of 10,683 women were enrolled; a complete set of data was obtained in 10,389 women. Women with normal or non-significant findings were invited for further colposcopical and cytological investigations after 2 years and 4 years, the other women were followed at 3- to 6-monthly intervals. In women with highly significant findings, histological investigation was performed. The total of 150 cases of moderate to severe dysplasia (i.e. cervical intraepithelial neoplasia, grade II, CIN II), 83 cases of carcinoma in situ (CIN III) and 21 cases of invasive carcinoma (INCA) were detected. More than 60% of the patients were ill at enrollment, the other cases developed in subjects with originally slightly suspicious (27 CIN II, 17 CIN III, 3 INCA) or negative findings (30 CIN II, 12 CIN III, 3 INCA). Analysis of the data indicated significantly positive correlation of one or more of these clinical conditions with a number of sexual and reproduction-related attributes of which early age at first intercourse was most consistent. Among the other attributes, the smoking habit was associated with the highest risk of developing the disease. A negative correlation of cervical neoplasia with several attributes was demonstrated; of these diathermoelectrocoagulation of the ectopic epithelium and transformation zone of cervix was the most important single protective factor. On the basis of these findings, control subjects were selected for serological studies.

Adult↗
PubMed1984

Prospective study on the relationship between cervical neoplasia and herpes simplex type-2 virus. II. Herpes simplex type-2 antibody presence in sera taken at enrollment.

Sera obtained at enrollment in the study from patients suffering from moderate to sever dysplasia (cervical intraepithelial neoplasia grade II), carcinoma in situ (cervical intraepithelial neoplasia grade III) and invasive carcinoma, or developing any of these conditions in the course of the prospective study, and from control subjects, were examined for herpes simplex type-2 (HSV-2) antibody presence. The controls were matched with the patients by age, age at first intercourse, number of sexual partners, smoking habits and history of diathermoelectrocoagulation of the ectopic epithelium and transformation zone of cervix. Only those subjects were selected as controls who remained free of pathological colposcopical and cytological findings throughout the observation period, i.e. for at least 4 years after their serum sample was obtained. The microneutralization test (MNT) and type-2-specific solid-phase radioimmunoassay (SPRIA) were used as serological tests. No difference in the prevalence of HSV-2 antibody between the patients and controls was revealed by either test. Various combinations of the results from the two tests also failed to show any difference between patients and controls. Moreover, no significant differences were observed in the prevalence of HSV-2 antibody between patients suffering from the various pathological conditions and those diagnosed at enrollment and later in the course of the study. These results do not provide any support for the hypothesis of the involvement of HSV-2 in cervical neoplasia.

Animals↗
PubMed1984

Effects of n-butyrate and phorbol ester (TPA) on induction of Epstein-Barr virus antigens and cell differentiation.

N-Butyrate, an effective inducer of synthesis of Epstein-Barr virus (EBV) antigens in virus-producer P3HR-1 cells, has recently been shown (2) to induce morphological differentiation towards plasma cell in nonproducer Raji cells. The effects of n-butyrate and 12-O-tetradecanoylphorbol-13-acetate (TPA) on both EBV-antigen induction and cell differentiation in two virus-nonproducer lymphoblastoid cell lines, Raji and NC37, were now studied. The following observations were made (1). On its own either drug induced 1-2 per cent of cells to EBV-early-antigen positivity in both lines; their mixture induced 35 and 15 per cent positive cells in Raji and NC37 respectively (2). In Raji, n-butyrate induced about 80 per cent of cells to differentiate to plasmablast or plasma cell morphology, whereas TPA only induced the early stages of differentiation in 8 per cent of cells; a mixture of both inducers produced a similar effect as TPA alone. The addition of TPA alone or butyrate-TPA mixture led to some cellular alterations resembling virus-specific changes in virus-producer cell lines. In NC37, either drug alone or their mixture drove 13 per cent of cells to differentiate into plasmablasts or earlier stages of differentiation. In the presence of TPA protrusions and "loops" were seen on cell surfaces. Evidently, the stage of differentiation at which B-lymphoblastoid cell lines have been arrested can be changed in vitro. However, cell-line dependent and inducer-dependent differences in the differentiation response were apparent.

Antigens, Viral↗
PubMed1984

Determination of herpes simplex virus type-specific antibodies by solid-phase RIA on Helix pomatia lectin-purified antigens.

Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) antibodies in humans and animals were determined by a micro-solid-phase radioimmunoassay with Helix pomatia lectin/Sepharose 4B-purified antigens from HSV-1- and HSV-2-infected cells. A low but constant heterotypic reactivity was found with HSV-1 antigen, whereas HSV-2 antigen was type specific, as evidenced by (1) its reactivity with sera from HSV-2- but not with those from HSV-1-immunized animals, (2) its reactivity with monoclonal antibody to glycoprotein C but not with that to other HSV-2 glycoproteins, and (3) the negative results obtained in serum samples from 57 children, of whom 49 possessed HSV-1 neutralizing antibody. Antibody to HSV-2 (anti-HSV-2) was detected in serum samples from 14 of 16 subjects treated for genital herpetic lesions. The prevalence of anti-HSV-2 in women did not differ in the 25-35- and 36-45-year-old age groups but did correlate with the number of sex partners, with only 10% of women reporting one sex partner and 33% of those reporting more than 10 sex partners having anti-HSV-2.

Adult↗
PubMed1984

Presence of Epstein-Barr virus DNA in carcinomas of the palatine tonsil.

The presence of Epstein-Barr virus genetic material was demonstrated in thin sections of biopsy specimens in 6 of 7 carcinomas of human palatine tonsil by the in situ hybridization test. The biopsy specimens from 4 tonsillar carcinomas exhibited a strong positive reaction; two biopsy specimens were weakly positive. Two tumor-free biopsy specimens were negative. None of the thin sections reacted with 3H-labeled herpes simplex virus DNA probe.

Adult↗
PubMed1983

Association of some supraglottic laryngeal carcinomas with EB virus.

Thin sections of biopsies from five patients with supraglottic laryngeal carcinoma who possessed antibody to early antigen of EB virus were examined for the presence of EB virus nuclear antigen (EBNA) and EB virus DNA by cytological hybridization in situ. Both EBNA and EB virus DNA were found in the tumour cells of three of the patients. The present findings suggest an association between EB virus and supraglottic carcinoma of the larynx.

Aged↗
PubMed1983

Relationship between Epstein-Barr virus nuclear antigen and DNA genome number in superinfected and induced lymphoblastoid cell lines.

The relative contents of Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) and average numbers of EBV genome equivalents per cell were determined (i) in Raji cells superinfected with P3HR-1 virus, (ii) in Raji cells induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and sodium n-butyrate and (iii) in P3HR-1 cells induced by TPA and sodium n-butyrate. This treatment was followed by increases in the percentage of early antigen (in both Raji and P3HR-1 cells) and virus capsid antigen-positive cells (in P3HR-1 cells) and increases of approximately 20-fold in the average number of EBV DNA equivalents in superinfected Raji cells and in TPA- and sodium n-butyrate-induced P3HR-1 cells. However, the content of EBNA in these cells dropped. This was revealed by a decrease in both the complement-fixing antigen content and in the proportion of EBNA-positive cells as determined by anti-complement immunofluorescence. Thus, the positive correlation found previously between the content of EBNA and the number of EBV genome equivalents per cell in proliferating lymphoblastoid cultures does not seem to apply to the situation in either superinfected Raji cells or in P3HR-1 cells induced by TPA and sodium n-butyrate.

Antibody Specificity↗
PubMed1983

Induction of Epstein-Barr virus antigens and DNA-polymerase activities in P3HR-1 cell line and its subline passaged in the presence of phosphonoformate.

Lymphoblastoid cell line P3PFA was derived from P3HR-1 cells by long-term cultivation in the presence of phosphonoformate (PFA). Spontaneous production of Epstein-Barr virus antigens in PFA-selected subline was markedly reduced in comparison with the original cell line. Induction of early antigen (EA) and viral capsid antigen (VCA) syntheses with 5-iodo-2-deoxyuridine (IUDR), n-butyrate and 12-o-tetradecanoyl phorbol-13-acetate (TPA) was significantly less efficient in P3PFA than P3HR-1 cells. This was most likely associated with reduction in the number of viral genome copies per P3PFA cell that decreased more than one hundred times in comparison with P3HR-1 line. The synthesis of EA in both cell lines was not inhibited in the presence of PFA. On the other hand, PFA inhibited the synthesis of VCA by 95 and 30% in P3HR-1 and P3PFA, respectively. The relative resistance of VCA synthesis to PFA in P3PFA cells was not due to the presence of a drug-resistant virus-specific DNA-polymerase. It is noteworthy that the activity of virus-specific enzyme was markedly reduced, while cellular enzyme activity was significantly enhanced in induced P3PFA cells when compared to P3HR-1 cells treated in the same way.

Antigens, Viral↗
PubMed1982

Effects of n-butyrate on Epstein-Barr virus-carrying lymphoma lines.

n-Butyrate has been shown to induce Epstein-Barr virus (EBV) antigen synthesis in certain EBV-carrying lymphoma lines (Luka et al., 1979). We have studied the effect of n-butyrate on two EBV-positive Burkitt lymphoma lines by immuno-fluorescence and electron microscopy. In the producer line P3HR-1, the drug induced not only early antigen (EA) and virus capsid antigen (VCA) synthesis, as shown before, but also increased the number of cells containing virus particles. The transition from VCA expression to the formation of virus particles was much more effective in treated cells than in EBV antigen-producing cells of the same line. The productive cycle was associated with the development of characteristic morphological changes. In the non-producer Raji cells, n-butyrate induced EA in only a minor fraction of the cells. There were, however, clear signs of differentiation in the direction of plasma cells. Two days after the addition of n-butyrate 80% of the Raji cells could be classified as plasmablasts. After 72 h, 20% of the cells appeared as typical plasma cells.

Antigens, Viral↗