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M A EPSTEIN

Publications and source records attributed to M A EPSTEIN.

At least 19 recordsLinked to original sources
PubMed1965

MORPHOLOGICAL AND BIOLOGICAL STUDIES ON A VIRUS IN CULTURED LYMPHOBLASTS FROM BURKITT'S LYMPHOMA.

Lymphoblasts of two tissue culture strains (EB1 and EB2) from different biopsy specimens of Burkitt's lymphoma have been examined in thin sections by electron microscopy, and have each been found to carry a morphologically identical virus. The virus was observed in samples taken over many months, being present in about 1 to 2 per cent of the cells in two forms: Immature particles about 75 mmicro in diameter which were seen in both the nucleus and cytoplasm; and larger mature particles with a diameter of 110 to 115 mmicro, which were either within membrane-bounded cytoplasmic spaces or at the cell surface. There was some indication that the particles matured by budding through the cytoplasmic membranes. Both types of particle occurred in dead degenerating cells or, less frequently, in intact altered cells. The characteristic alterations of the latter included margination of the chromatin, fragmentation of the nuclear envelope, beaded opaque material in the mitochondria, and, with one of the cell strains (EB1), sheaves of altered spindle tubules. All attempts to isolate and identify the virus carried by the two strains of lymphoblasts failed. No pathological effects were caused in 8-day chick embryos inoculated either with whole lymphoblasts or extracts of disrupted lymphoblasts, using the intraallantoic, amniotic, and chorioallantoic routes, and the extraembryonic fluids of such chicks were without haemagglutinating activity for human, chicken, guinea pig, or monkey erythrocytes. Whole lymphoblasts or lymphoblast extracts were likewise without effect when inoculated intraperitoneally into newborn hamsters or two strains of newborn mice. Similar lymphoblast inocula did not cause detectable changes in 9 different test tissue culture systems even after 8 blind passages. The nature of the unknown, unidentified virus in the cultured lymphoblasts from Burkitt's lymphomas is considered and its possible relationship to the cells discussed.

Animals↗
PubMed1965

CYTOCHEMICAL AND ELECTRON MICROSCOPICAL OBSERVATIONS ON THE PRESENCE AND ORIGIN OF ADENOSINE TRIPHOSPHATASE-LIKE ACTIVITY AT THE SURFACE OF TWO MYXOVIRUSES.

Dawson, C. R. (The Middlesex Hospital Medical School, London, England), M. A. Epstein, and K. Hummeler. Cytochemical and electron microscopical observations on the presence and origin of adenosine triphosphatase-like activity at the surface of two myxoviruses. J. Bacteriol. 89:1526-1532. 1965.-HeLa cells infected with either fowl plague virus (FPV) or Newcastle disease virus (NDV) were examined in thin sections by electron microscopy. Preparations were studied both after direct fixation and embedding and after the application of cytochemical staining for enzymes splitting adenosine triphosphate. Viral particles were identified by their size and characteristic structure, and were found to form at the cell surface by budding out through structurally altered plasmalemma. After cytochemical staining for adenosine triphosphatase activity, extracellular FPV or NDV particles lying close against cell membranes with enzyme activity likewise carried this function, whereas those particles which were associated with cell surfaces without reaction product were themselves free from it. This correspondence between enzyme function in cell membranes and the outer viral membranes of newly formed particles adjacent to them indicates that surface enzymatic capability of the host cell survives even when the cell membrane undergoes morphological and antigenic alteration into myxovirus outer membrane.

Adenosine Triphosphatases↗
PubMed1964

HAIR-SPRAYS.

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Aerosols↗
PubMed1964

THE ENTRY AND DISTRIBUTION OF HERPES VIRUS AND COLLOIDAL GOLD IN HELA CELLS AFTER CONTACT IN SUSPENSION.

The way in which herpes virus of a well adapted strain penetrates susceptible HeLa cells has been investigated using thin sectioning techniques for electron microscopy. Mature virus particles and cells were mixed together in suspension cultures for 15, 30, 60, or 120 minutes so that the stages in virus uptake could be followed in sequence. The ingestion of particles of colloidal gold by HeLa cells under similar conditions was studied for comparison in parallel experiments. After 15 minutes' contact, the mature virus was found adsorbed on the surface of the cells but separated from them by a narrow gap in which phosphotungstic acid staining was sometimes able to reveal an extraneous coat which appeared as an amorphous layer on the outer aspect of the plasma membrane. When mixing continued for longer the particles were present in deep invaginations or actual cytoplasmic vacuoles, with their outer layers in various stages of stripping and digestion. The stripped, naked, central portion of the virus was occasionally found in these vacuoles but was more commonly free in the cytoplasmic matrix; the mode of transition between these sites could not be determined. Where contact continued for 2 hours these phenomena were much less frequently observed. The larger particles of colloidal gold were ingested in the same way as the virus, but smaller ones were taken up in micropinocytosis vesicles. The gold passed through membrane-bounded cytoplasmic spaces to accumulate in vacuoles from which, in contrast to herpes particles, it did not escape. These findings are discussed, and considered with particular reference to their bearing on the initiation of infection, the uptake and disposal of particles by cells, and the influence on the latter of virus morphology.

Cytoplasm↗