Search PubMed⌕ Search

Biomedical subjects

S Antohi

Publications and source records attributed to S Antohi.

36 records · Page 2Linked to original sources
PubMedDate not supplied

Polycation-cell surface interactions and plasma membrane compartments in mammals. Interference of oligocation with polycationic condensation.

At lower concentrations, polyarginine, polylysine, protamine, histones H1, H2A, H2B and H3 cause lysis of human erythrocytes, whereas at higher concentrations inner histones are not hemolytic but induce only surface condensation and alterations in the cell-shape. Antibody coated erythrocytes treated with polyarginine result in ghost-like spheres having globular bodies 1 micron in diameter on the surface. Human fibroblasts and lymphocytes, and Ehrlich ascites cells treated with polyarginine also form surface globular bodies similar in size. Nucleate cell-polyarginine mixtures with lower polycation doses result in cytolysis, while higher polycation doses produce pyknosis of the cell surface accompanied by reorganization of a membrane-like structure. Changes in spectrofluorometric values result from 1,6-diphenyl-1,3, 5-hexatrien binding to cell lipids, match the plasma membrane alterations. Reciprocal shake incubation amplifies and/or conditions these polycation-induced alterations. The homogeneity of pyknotic surface bodies and the apparent polycationic membrane reorganization requiring oscillatory friction forces suggest the preexistence of a multizonal glycocalyx distribution corresponding to plasma membrane compartments. The possible role of this compartmentalization in receptor and membrane recycling, as well as the involvement of reversible catalytic-like polycation condensation in macromolecular changes are discussed.

Animals↗
PubMedDate not supplied

Viral oncogenes, proto-oncogenes and homoeotic genes related to cell proliferation and differentiation.

Molecular studies on viral oncogenes and their products have led to the discovery of physiological proto-oncogenes, involved in the control of cell proliferation and gene activation. Other genetic and molecular investigations, initiated in Drosophila melanogaster and continued in different multicellular eukaryotes, have made evident the homoeotic genes, which are directly correlated with cell specialization, in the complex processes of differentiation and morphogenesis. Both gene classes are conserved to a high extent during evolution. They are involved in the eukaryotic mechanisms of differentiation control and proto-oncogenes, in particular, are related to malignant transformation. Some available data suggest a certain extent of relatedness between the gene products of both gene classes. A differentiation trigger model, including retroviral transposition, homoeotic genes and proto-oncogenes is discussed.

Animals↗
PubMedDate not supplied

Plasma membrane compartmentation, related to the mechanism of myxo- and paramyxovirus invasion, to receptor mobility and membrane balance.

According to the model of plasma membrane compartmentation into functional endocytosis-exocytosis units it is suggested that the respective compartments may also take part in the receptor mediated internalization of viruses. The primary effect of myxo- and paramyxovirus invasion would consist in the intercalation of new microzones in the recycling of the host cell membrane. Viral receptor lateral mobility is a result of the zonal migration of the entire plasmalemma, due to the processes of exocytosis and endocytosis, continuously adding and removing, respectively, different membrane microzones.

Cell Compartmentation↗
PubMedDate not supplied

Light scattering from polycation--virus--oligocation mixtures.

The effect of a polycation (histone H2A) and of oligocations (spermine, spermidine and putrescine) on Sendai and influenza virus particles was investigated by light scattering measurements at 90 degrees and at various wavelengths. The method allows the study of the changes in the size and shape of virus particles in suspension.

Cations↗
PubMedDate not supplied

Common model of normal cell differentiation and oncogenesis based on the mutation--recombination effects of transposable genetic elements and of provirus states.

Cell differentiation would result from a sequence of mutation--recombination events that occur in quantal cell cycles, initiating cell lineages. The cytogenomic proviruses--transposable elements ensemble would represent the mutation--recombination equipment of differentiation. Carcinogenesis, as a consequence of multicausally induced mutation--recombination events, would likewise occur in a particular quantal cell cycle resulting in the malignant cell lineage. Superposing the environmental causes of malignancy over those of genetic diseases, the model suggests common prevention methods.

Animals↗
PubMedDate not supplied

The genetics of viral infection pathology.

The genetic diversity of viruses and the genetic constitution (polygenic configuration) of susceptible organisms participate together in the determination of a virus disease and of its clinical forms. Genes of sensitivity to viral infection, genes of nonspecific defense (encoding for interferons, complement factors), immune response regulating genes and immunoglobulin genes would form the background of an intrinsic polygenic group involved in viral infection pathology.

Alleles↗
PubMedDate not supplied

Polycation-induced alterations of the envelope surface of influenza and parainfluenza viruses.

Natural macromolecular polycations (protamine, histones H1, H2A, H2B and H3) caused the clustering of influenza and parainfluenza viruses into aggregates heterogeneous in size, as well as a decrease in their hemagglutinating capacity. Polycation-induced virus alterations consisted in surface pyknosis and an increase most efficient as regards the interaction with viruses.

Chemical Phenomena↗