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Biomedical subjects

K Hummeler

Publications and source records attributed to K Hummeler.

44 records · Page 3Linked to original sources
PubMed1967

New assay procedure for separation of mycoplasmas from virus pools and tissue culture systems.

Presence of mycoplasma organisms in tissue culture systems and virus pools was detected by titration of the contaminated material on agarose-suspended BHK21/13S cells. The use of this method permitted isolation of mycoplasmas which could not be detected by standard assay methods. Mycoplasma colonies at concentrations ranging from 10(4) to 10(6) colony-forming units/ml in agarose-BHK21/13S media could be distinguished from virus plaques, and the two populations of microorganisms could be easily disassociated either by electron microscopy or by biological methods. All isolated mycoplasmas were identified in growth inhibition tests as belonging to the GDL group. The growth inhibition test on agarose-BHK21/13S cell suspension plates could also be applied directly to those strains which could not be isolated by standard assay procedures.

Animals↗
PubMed1966

Electron microscopic observations on antibody-producing cells in lymph and blood.

Antibody-producing cells have been identified among cells obtained from efferent lymphatic vessels, the thoracic duct, and peripheral blood. These cells, which produced plaques of hemolysis and which were quite rare (20 to 50 per million), due in most instances to 19S antibody, were located and studied by electron microscopy. Of the antibody-producing cells found in these three sites there were several features common to all: small size (5 to 8 micro), generally spherical shape, approximately central position of the nucleus, and retention in the nucleus of the condensations of chromatin characteristic of the lymphocyte. The differences among the cells of these sources were largely in the relative amount and state of organization of the organelles of the cytoplasm. In cells of the efferent lymphatic vessel and the thoracic duct, the endoplasmic reticulum showed a range from relative scarcity to considerable numbers of well organized channels. Between these extremes were cells with a considerable amount of endoplasmic reticulum, the channels disorganized and sectioned at various angles. The cytoplasmic matrix of all of these contained a profusion of polyribosomes. Antibody-producing cells obtained from peripheral blood showed, around the roughly spherical nucleus, a ring of cytoplasm which was narrow, but wholly organized into parallel lamellae of endoplasmic reticulum, with many polyribosomes between these, and a large Golgi body. Some similarities and some differences of these cells, in comparison with antibody-producing cells obtained from lymph nodes, have been indicated.

Antibody Formation↗
PubMed1966

Electron microscopic observations on antibody-producing lymph node cells.

Lymph node cells of rabbits injected with sheep erythrocytes, identified as antibody-producing by their ability to produce plaques of hemolysis in erythrocyte-containing agar layers, have been examined by electron microscopy, by the use of a procedure devised for subjecting single cells to such examination. The antibody-producing cells thus examined were found to fall into two classes, according to the current terminology: some were in the category of lymphocytes, and others, in the category of plasma cells. Within each class, cells were found to vary in certain characteristics, especially in the degree of development of such organelles as the nucleolus, Golgi apparatus, and the endoplasmic reticulum. In the case of the endoplasmic reticulum especially, it could be seen that a series of these plaque-producing cells, ranked in order of increasing size and development of the endoplasmic reticulum, would extend over a considerable range from those lymphocytes with the least developed organelles to the mature plasma cells with the greatest development of these structures.

Animals↗
PubMed1964

Heterogeneity of apparently complete poliovirus particles.

Tumilowicz, Joseph J. (Children's Hospital of Philadelphia, Philadelphia, Pa.), and Klaus Hummeler. Heterogeneity of apparently complete poliovirus particles. J. Bacteriol. 87:1105-1113. 1964.-A chromatographic procedure was developed for separating the N from the H complement-fixing antigen of poliovirus. This procedure concomitantly effected some separation of classes of N particle. The ratio of physical virus particles (PVP) to plaque-forming units (PFU) in N-reactive fractions varied from 6 to 51. Fractions with the lowest PVP-PFU ratios represented a considerable enrichment of PFU, when compared with the original ratio in each experiment. A direct relationship was found between the ratio of complement-fixing units of N antigen [CFU(N)] to 10(10) PVP and the ratio of PFU to 10(10) PVP for most of the N-reactive fractions. Large differences among the PVP-CFU(N) ratios, along with relatively constant PFU-CFU(N) ratios for most of the N fractions, indicated that N antigen is not distributed equally among non-H particles. Two possibilities, both compatible with the results, were discussed for the manner in which N antigen might be distributed. An absolute value of 10(7) PVP-CFU(N) was proposed for particles with a PVP-PFU ratio of 1.

Antigens↗