Retroviruses can cause different types of leukemias in chickens. A small group of virus strains induce acute leukemias and transform hematopoietic cells in vitro. We have shown that cells transformed in vitro by erythroblastosis and myeloblastosis viruses resemble in vivo transformed cells in their phenotype of differentiation. The erythroblastosis virus AEV carries two cell-derived oncogenes termed erbA and erbB. The analysis of AEV using deletion mutants showed that erbB is the main oncogene which is capable of inducing a "mild" form of erythroleukemia. The added action of the erbA oncogene leads to an aggressive, more "advanced" form of erythroleukemia. The erbA oncogene itself, however, does not exhibit any detectable biological activity. Using temperature sensitive mutants of AEF we could also show that erbB, together with erbA, blocks the differentiation of hematopoietic precursor cells. The continued synthesis of a functional erbB-encoded protein is necessary to maintain the "blocked", i.e. leukemic state of the infected cells.

Alpharetrovirus↗

PubMedDate not supplied

A new angiotensin-II- receptor blocker, CGP 48933: local tolerance and effect on intraocular pressure. A pilot study.

CGP 48933, a new angiotensin-II-receptor antagonist, has been shown to lower intraocular pressure (IOP) in two different rabbit glaucoma models in a dose-dependent manner after local application. As a further step a pilot study was performed in human eyes. The trial consisted of three parts. Parts 1 and 2 comprised a double-masked intraindividual trial between CGP 48933 and its vehicle (saline) in five healthy volunteers (Part 1) and five patients with early stages of primary open-angle glaucoma (Part 2), to assess local tolerance and the effect on IOP. Part 3 was a single-masked intraindividual trial between CGP 48933 and saline, to find the effective dose range of the new compound. Local tolerance was assessed as excellent in all subjects. No conjunctival hyperemia burning or itching occurred. There were no significant changes in IOP from baseline in drug or vehicle-treated eyes. In addition, there was no dose-dependent (200 micrograms to 1 mg) effect of CGP 48933 on IOP. Systemic blood pressure, heart rate and pupil size did not change during the observation period. Topical application of CGP 48933 in its present formulation is thus not suitable for lowering IOP in humans.

Administration, Topical↗

PubMedDate not supplied

In vitro transformation of chicken bone marrow cells with avian erythroblastosis virus.

An in vitro transformation of bone marrow cells has been demonstrated for two strains of avian erythroblastosis virus (AEV-R and AEV-ES4). The transformed cells were indistinguishable from in vivo transformed erythroblasts in morphology and staining characteristics and could be propagated to large numbers. The transformation efficiency could be greatly increased by the addition of dimethylsulfoxide (DMSO). The number of foci appearing in the presence of DMSO was proportional to the virus concentration.

Alpharetrovirus↗

PubMedDate not supplied

Expression of virus specific morphological cell transformation induced in enucleated cells.

Chick embryo fibroblasts infected by a temperature sensitive mutant of Rous sarcoma virus were enucleated with Cytochalasin B. The cytoplasts were still able to transform morphologically when shifted from nonpermissive to permissive temperature, and to revert ot normal morphology when shifted from permissive to nonpermissive temperature. This indicates that the viral gene product responsible for transformation acts primarily on cytoplasmic or membrane components and not on the nucleus.

Animals↗

PubMedDate not supplied

Properties of mouse leukemia viruses. XV. Electron microscopic studies on the organization of Friend leukemia virus and other mammalian C-type viruses.

Explore the source record for details and available documents.

Animals↗