Infectious deoxyribonucleic acid (DNA) was extracted from green monkey kidney (CV-1) cultures at various times after the cultures were infected with simian virus 40 (SV40) at input multiplicities of 0.01 and 0.1 plaque-forming unit (PFU) per cell. A pronounced decrease in infectious DNA was observed from 3 to 16 hr after virus infection, suggesting that structurally altered intracellular forms may have been generated early in infection. Evidence is also presented that SV40 DNA synthesis requires concurrent protein synthesis. DNA replication was studied in the presence and absence of cycloheximide in: (i) SV40-infected and uninfected cultures of CV-1 cells; (ii) cultures synchronized with 1-beta-d-arabinofuranosylcytosine (ara-C) for 24 to 30 hr prior to the addition of cycloheximide; and (iii) in heterokaryons of SV40-transformed hamster and susceptible monkey kidney cells. DNA synthesis was determined by pulse-labeling the cultures with (3)H-thymidine at various times from 24 to 46 hr after infection. In addition, the total infectious SV40 DNA was measured. Addition of cycloheximide, even after early proteins had been induced, grossly inhibited both SV40 and cellular DNA syntheses. The activities of thymidine kinase, DNA polymerase, deoxycytidylate deaminase, and thymidylate kinase were measured; these enzyme activities remained high for at least 9 hr in the presence of cycloheximide. SV40 DNA prelabeled with (3)H-thymidine before the addition of cycloheximide was also relatively stable during the time required for cycloheximide to inhibit further DNA replication.

Animals↗

PubMed1969

Properties of simian virus 40 rescued from cell lines transformed by ultraviolet-irradiated simian virus 40.

Simian virus 40 (SV40) strains have been rescued from various clonal lines of mouse kidney cells that had been transformed by ultraviolet (UV)-irradiated SV40. To learn whether some of the rescued SV40 strains were mutants, monkey kidney (CV-1) cells were infected with the rescued virus strains at 37 C and at 41 C. The SV40 strains studied included strains rescued from transformed cell lines classified as "good," "average," "poor," and "rare" yielders on the basis of total virus yield, frequency of induction, and incidence of successful rescue trials. Four small plaque mutants isolated from "poor" yielder lines and fuzzy and small plaque strains isolated from an "average" and a "good" yielder line, respectively, were among the SV40 strains tested. Virus strains rescued from all classes of transformed cells were capable of inducing the transplantation antigen, and they induced the intranuclear SV40-T-antigen, thymidine kinase, deoxyribonucleic acid (DNA) polymerase, and cellular DNA synthesis at 37 C and at 41 C. With the exception of four small plaque strains rescued from "poor" yielders, the rescued SV40 strains replicated their DNA and formed infectious virus with kinetics similar to parental SV40 at either 37 or 41 C. The four exceptional strains did replicate at 37 C, but replication was very poor at 41 C. Thus, only a few of the rescued virus strains exhibited defective SV40 functions in CV-1 cells. All of the virus strains rescued from the "rare" yielder lines were similar to parental SV40. Several hypotheses consistent with the properties of the rescued virus strains are discussed, which may account for the significant variations in virus yield and frequency of induction of the transformed cell lines.

Animals↗

PubMed1968

Activation of infectious SV40 synthesis in transformed cells.

Explore the source record for details and available documents.

Animals↗

PubMed1968

Studies on the immune bacteriolysis. 13. Leakage of enzymes from Escherichia coli during immune bacteriolysis.

Explore the source record for details and available documents.

Alkaline Phosphatase↗

PubMedDate not supplied

Hepatitis delta virus infection in different time periods in Japan.

To investigate the prevalence of hepatitis delta virus (HDV) infection in different time periods between 1973 and 1988, antibody to hepatitis delta antigen (anti-HD) was tested for in sera collected from 1088 cases with acute or chronic hepatitis B virus (HBV) infection treated at Kure National Hospital. Between 1979 and 1983, anti-HD was first detected in 16% (four of 25 cases) of patients with acute hepatitis B, in 6.8% (11 of 161 cases) of asymptomatic HBV carriers and 26% (51 of 196 cases) of those with chronic liver disease. Except for this time period anti-HD was hardly detected. These findings indicate that sporadic HDV infections existed in this area between 1979 and 1983.

Adult↗

PubMedDate not supplied

Risk of liver cirrhosis and hepatocellular carcinoma in subjects with hepatitis B and delta virus infection: a study from Kure, Japan.

To investigate the effect of hepatitis delta virus (HDV) superinfection on the long-term outcome of Japanese subjects with chronic hepatitis B virus (HBV) infection, we examined the presence of antibodies to hepatitis delta antigen (anti-HD) in serial serum samples collected from 1127 subjects with chronic HBV infection. The subjects were followed for at least 36 months (mean: 121.3 months) between 1973 and 1991. Among 69 cases where anti-HD was detected, eight (12%) developed liver cirrhosis (LC) and six (9%) developed hepatocellular carcinoma (HCC). However, among 1058 cases without anti-HD, there were 43 patients (4%) who developed LC and 29 (3%) who developed HCC. The prevalence of LC and HCC was significantly higher among the cases with anti-HD than those without anti-HD. The proportion of LC and HCC per 1000 person years was 10.46 and 7.84, respectively among cases with anti-HD, and 4.05 and 2.73 among those without anti-HD, respectively. The overall relative risk of LC and HCC was 2.58 and 2.87, respectively; 95% confidence interval (CI): LC, 1.14-5.13; HCC, 1.03-6.23. These results indicate that in the Kure district in Japan, where HDV infection of persons infected with HBV is about 6%, such superinfection increases the risk of LC and HCC.

Adolescent↗