ISSN:0300-5526    

DOI:10.1159/000150136

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150137

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150138

出版商:S. Karger AG    

年代:1990

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150139

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Cytomegalovirus (CMV) infection induces a series of cellular responses that resemble those observed in cells activated by growth factors or hormones including: hydrolysis of phosphatidylinositol-4,5-bisphosphate; Ca2+ influx and an increase in the cytosolic free [Ca2+]; an increase in Na+ entry; and, increases in cellular levels of cyclic AMP and cyclic GMP. The time courses for some of these responses appear to be markedly protracted relative to those observed for growth factors. The prolonged physiologic responses in CMV-infected cells appear to be related to modifications in the intracellular environment that are associated with the development of cytomegaly and with the phasing of CMV-directed macromolecular synthesis. For example, as the infected cell enlarges, the rate of CMV DNA synthesis increases by about 4-fold, late nuclear inclusions develop and progeny viruses are formed. When the CMV-induced activation signals are inhibited or their physiologic responses are blocked, then the yields of infectious CMV are substantially reduced. Furthermore, perturbation of the cell cycle resulting from induction of the cell activation process by CMV may be causally related to the induction of cellular damage by CMV, even in the absence of productive infection. Accordingly, the CMV-induced pathophysiologic cell activation responses represent potential targets for novel antiviral therapy.

ISSN:0300-5526    

DOI:10.1159/000150140

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

A previously-described herpes simplex virus type 2 DNA-binding protein with a molecular size of 38 kD has been further characterized. Using purified nucleocapsids, a DNase release assay, and intertypic recombinants, this protein was found to be a component of the nucleocapsid, intimately associated with the nuclear matrix, and encoded between 0.605 and 0.720 on the herpes simplex virus type 2 genome.

ISSN:0300-5526    

DOI:10.1159/000150141

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

SV40 large T antigen (T-ag) is a potent oncogene able to transform many cell types. The human alpha-1-antitrypsin (AAT) gene encodes the major serine protease inhibitor in plasma. The 5’ flanking sequence of the AAT gene contains cis-acting elements that specify the expression of reporter genes in transgenic mice. Although the AAT gene is expressed primarily in the liver, it also is expressed in epithelial cells of the stomach, kidney, intestine and pancreas. A fusion gene with the 5’ flanking region of AAT driving the SV40 large T-ag gene was used to generate transgenic mice. Between 2 and 6 months of age, 6 of 7 founder mice developed hepatic neoplasms. Kidney hyperplasia (3/7) and carcinomas of the stomach (4/7) and pancreas (1/7) also were observed. Tumor cells in the different sites expressed T-ag that was detectable by immunohistochemical staining. A transgenic mouse line (1812) was established; liver tumors develop reproducibly in all offspring. Cellular changes progressing to liver tumor formation occur in discrete stages with predictable kinetics in animals of the 1812 line: (i) embryonal/fetal stage, no major histological changes; (ii) newborn to 2 weeks of age, hyperplastic livers with minor cellular changes; (iii) mice between 3 and 8 weeks of age, diffuse liver cell dysplasia without observable tumor nodules; (iv) mice 8 weeks of age and older, hepatocellular carcinomas and hepatoblastomas in a background of liver dysplasia. There was uniform expression of T-ag in the majority of hepatocytes in the first two stages, whereas the dysplastic stage was characterized by variation in both the intensity of staining and the proportion of positive cells. Most tumor nodules expressed high levels of T-ag, but occasional negative and very weakly staining nodules were observed. T-ag was found complexed with the cellular p53 protein in tumor cells. This transgenic mouse system provides a practical model for the molecular analysis of defined steps in hepatocarcinogene

ISSN:0300-5526    

DOI:10.1159/000150142

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Human immunodeficiency virus 1 (HIV-1) produced in the human T lympho-blastoid H9 cell line infected cells of that line more readily than cells of the human monocytoid U937 line. While both cell lines expressed detectable levels of the CD4 molecule on their surfaces, the H9 and U937 cell lines differed in expression of major histocompatibility complex class I and class II antigens. Both H9 and U937 cells were infected initially with HIV-1 derived from H9 cells. Cell-free culture supernatants were harvested after the cells had been infected for at least 1 month. Culture supernatant from HIV-infected H9 cells was used to infect H9 and U937 cells. Conversely, culture supernatant from HIV-infected U937 cells was used to infect H9 and U937 cells. The percentages of cells infected at each of several time points during the first few days after infection were determined by flow cytometric analysis of cell-associated HIV-1 major core protein p24. Infection of each cell line was more efficient when the cell type infected was identical to that in which the infecting supernatant was produced. However, this difference in tropism was not generated early after infection of each cell line, as might have been expected if this effect were mediated by cell surface molecules acquired during the process of budding through the cell membrane.

ISSN:0300-5526    

DOI:10.1159/000150143

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Epithelial chips of human foreskin or cervix infected in vitro with one strain of human papillomavirus type 11 (HPV-11) and subsequently transplanted to the renal capsule of athymic mice will yield, after 3 months of in vivo incubation, epithelial cysts that are morphologically transformed and appear identical in every way to human condylomata. These cysts synthesize virus RNA, DNA, proteins, and infectious virions. The cysts can be utilized as a source of virus for continued passage of infection. The original HPV-11 infecting material was a cell-free saline extract of pooled human vulvar condylomata. DNAs of other HPV types were not detected in this material by either dot blot or Southern blot analyses. The copy number of HPV-11 virus genomes per cell genome in experimental condylomata ranged from about 200 to 1,000, a range expected for episomal papillomavirus DNA. Analyses of cloned HPV-11 DNA (pBT-1) from experimental lesions demonstrated that the size and restriction endonuclease map of the HPV-11-Hershey isolate closely matched that of the prototype. A few nucleotide changes that were detected during analyses of pBT-1 DNA resulted either in no amino acid change or a conservative change of amino acid. Physical characterization of the cloned experimental HPV-11 DNA as well as HPV typing in clinical lesions and experimental cysts are presented.

ISSN:0300-5526    

DOI:10.1159/000150144

出版商:S. Karger AG    

年代:1990

数据来源: Karger

摘要:

Monoclonal antibodies were used to localize five antigenic sites in the sequence of the Sendai virus NP gene. NP-specific peptides, expressed in Escherichia coli from the cloned gene served as antigens for blot analyses to determine the specificity of antibody binding. The antigenic sites were associated primarily with the C-terminal half of the protein.

ISSN:0300-5526    

DOI:10.1159/000150145

出版商:S. Karger AG    

年代:1990

数据来源: Karger