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Biomedical subjects

E G Diacumakos

Publications and source records attributed to E G Diacumakos.

At least 19 recordsLinked to original sources
PubMed1980

Replication and expression of thymidine kinase and human globin genes microinjected into mouse fibroblasts.

A mixture of two recombinant plasmids was microinjected into mouse thymidine kinase-negative fibroblasts (L cells). One plasmid contained the thymidine kinase gene of herpes simplex virus type I and the other contained the human beta globin gene. Seven fibroblast colonies arising from injected cells incubated in hypoxanthine/aminopterin/thymidine medium were analyzed. These microinjected cells were shown to: (i) produce functionally active herpes simplex type I thymidine kinase enzyme, (ii) replicate the human beta globin gene, and (iii) produce human beta globin mRNA sequences at low levels. Thus, the genetic defect (lack of thymidine kinase activity) was corrected by the microinjected thymidine kinase gene, and a coinjected human beta globin gene was replicated and weakly expressed.

Animals↗
PubMed1977

The electrophysiological mapping of compartments within a mammalian cell.

The electrical properties of structures within an intact cell were examined by impalement with micropipette electrodes. Mean potential differences (PDs) measured from interphase HeLa cells showed that internal membrane-bounded compartments such as the nucleus, Golgi region, and the mitochondria were more negative than the cytoplasm with respect to an external grounding electrode. The nuclear PDs, unlike Golgi and cytoplasmic PDs, shifted during interphase and reached a peak value shortly before mitosis. The positioning of micropipettes was confirmed by electron microscope examination of marker solutions that were microinjected into specific intracellular regions. The combination of methods described here offers a new approach for the study of physiological events within intact, living cells.

Cell Division↗
PubMed1977

Random arrangement of mitotic chromosomes in radial metaphases of the Indian muntjac.

The positioning of metaphase chromosomes of the Indian muntjac (Muntiacus muntjak) in the radial metaphase array was investigated using two methods for examining cells. Large numbers of radial metaphase figures were obtained by mitotic shake-off. Treatment with hypotonic solution, fixation, and spreading onto glass slides did not disrupt the radial metaphase configuration of a proportion of the cells. Analysis of 567 cells for the arrangement of six of the seven muntjac chromosomes revealed a random positioning of each chromosomes within the radial array. These results were corroborated by results obtained from 101 living cells oriented with microneedles to enable examination of radial metaphases with phase-contrast microscopy.

Animals↗
PubMed1973

Microsurgically fused human somatic cell hybrids: analysis and cloning.

Cell fusion by microsurgery permits production of specified bicellular hybrid cells with very high efficiency. Systematic analysis of the fate of bicellular hybrids reveals fundamental properties of cells in accordance with cell type. Bicellular hybrids that do not proliferate survive 1-21 days; those that do proliferate form clones 8-9 days after fusion.

Animals↗
PubMed1972

Fusion of mammalian somatic cells by microsurgery.

Mammalian somatic-cell hybrids can be formed in a direct and precise manner by microsurgery. Fusion of cells brought about in this way permits selection of specific, identifiable cells of the same or different types or species and their fusion at telophase.

Animals↗
PubMed1970

A microsurgical methodology for human cells in vitro: evolution and applications.

A methodology for micromanipulating human cells of normal and malignant origin, in vitro, has evolved from the study of about 2000 HeLa, ERK (a subline of HeLa cells), and human embryonic lung cells during interphase and mitosis. It is now possible to microinject interphase cells with aqueous and nonaqueous fluids intracytoplasmically. Chromosomes from human embryonic lung metaphase cells have been transplanted. Chromosomes have been manipulated within mitotic human embryonic lung, ERK, and HeLa cells. Clones have been obtained from HeLa cells subjected to such manipulation. Predictable derangements of mitotic cells and their progeny have been obtained. Intranuclear injections of silicone oil, DNA, and sodium chloride solutions have been made with survival of the cells. HeLa cells have been cloned from such injected cells. Subcellular fractions have been introduced into the nuclei and cytoplasms of HeLa and human embryonic lung cells. The lung cells have been subjected to nuclear micropuncture in groups and a clone has been obtained. Virus suspensions have been introduced into the nuclei of HeLa cells without killing the cells. Applications of this methodology are discussed.

Cell Line↗