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G Hager

Publications and source records attributed to G Hager.

At least 19 recordsLinked to original sources
PubMed1987

Expression of H-ras correlates with metastatic potential: evidence for direct regulation of the metastatic phenotype in 10T1/2 and NIH 3T3 cells.

Using three independent approaches, we studied the effects of H-ras on metastasis formation. Analysis of five in vitro-ras-transfected 10T1/2 clones with either flat or refractile morphologies revealed a relationship between metastatic potential, H-ras expression, and anchorage-independent growth. Four metastatic variants derived from a poorly metastatic, low-H-ras-expressing line all expressed high levels of H-ras RNA and grew efficiently in soft agar. Activation of H-ras expression in the metastatic tumors had occurred through amplification and rearrangement of H-ras sequences. In addition, preinduction of p21 synthesis in NIH 3T3 line 433, which contains v-H-ras under transcriptional control of the glucocorticoid-sensitive mouse mammary tumor virus long terminal repeat, significantly increased metastatic efficiency. Glucocorticoid treatment of normal or pEJ-transformed NIH 3T3 cells did not affect metastatic potential. These data reveal a direct relationship between ras expression and metastasis formation and suggest that metastatic and transformed phenotypes may be coregulated in ras-transformed 10T1/2 and NIH 3T3 cells.

Animals↗
PubMed1986

Cell cycle-dependent expression of a stable episomal human histone gene in a mouse cell.

We have constructed a recombinant plasmid that includes a cell cycle-dependent human H4 histone gene with 650 base pairs of 5' and 900 base pairs of 3' flanking sequences and the 69% transforming fragment of bovine papilloma virus. When transfected into C127 mouse cells, this plasmid is maintained as a stable episome with approximately 20 copies per cell. Micrococcal nuclease digestion indicates that the episomal human histone gene is packaged as chromatin. The human H4 histone transcript is initiated at the correct 5' start site and undergoes selective destabilization when DNA synthesis is inhibited. When C127 cells containing the episomal H4 histone gene are synchronized, the human H4 histone mRNA levels are regulated coordinately with DNA replication and parallel those of transcripts from the murine chromosomal H4 histone genes. Our results suggest that the regulatory sequences and/or regulatory molecules associated with murine and human histone genes are compatible. The human histone gene-bovine papillomavirus episome is therefore a viable system for studying cell cycle-regulated histone gene expression under conditions where control is not influenced at the site of chromosomal integration by cis-acting elements of genes normally not contiguous.

Animals↗
PubMed1978

[Ultrastructural and histochemical aspects of the rodlet cells from the bulbus arteriosus of Cyprinus carpio L. (Pisces: Cyprinidae) (author's transl)].

Morphological details of the "Stäbchendrüsenzellen" (PLEHN), rodlet cells syn. pear-shaped cells of the endothel from the Bulbus arterious of carps were studied in the electron microscope. From morphological characteristics, especially from the development of desmosomes with adjacent endothelial cells, it becomes evident, that the cells in question, which are very common in Teleostei, are not of parasitic nature. Specific protrusions of the apical cell poles towards the arterial lumen are indicative of a holocrine type of secretion.

Animals↗
PubMed1975

[Indications and results of operative exposure of traumatically damaged optic nerves (author's transl)].

The indications for operative treatment of traumatically damaged optic nerves are given and the results from microsurgical transethmoid approaches are communicated. This operation method has such a low risk, that it can be also used on patients with recent head injuries. The early diagnosis of traumatic optic nerve damage and the earliest possible exposure of the nerve with pressure relief of the traumatised optic nerves are important for possible success. The development of microsurgery of the orbit, the possibility of a low-risk anaesthetic, the use of modern post-operative therapy and observation make older treatments such as waiting for spontaneous return of vision out of date. During the operation undiagnosed dural tears and other secondary damage are often found, which can be repaired at the same time. This is a further argument for a broadly-based indication to operation.

Adolescent↗