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Biomedical subjects

Z Bentwich

Publications and source records attributed to Z Bentwich.

At least 163 records · Page 9Linked to original sources
PubMed1975

Osmotic behavior of normal and leukemic lymphocytes.

The response of normal human peripheral blood lymphocytes to a hypotonic environment may be divided into two phases: the cells first exhibit rapid osmotic swelling, followed by a slower shrinking phase, during which they regain their initial physiologic volume. This osmotic behavior is characteristic of most mammalian and avian nucleated cells so far examined. The normal human blood lymphocyte, however, shows the most rapid recovery phase (5 min). Lymphocytes from chronic lymphatic leukemia patients, in comparison, show a strikingly slower rate of return to their initial isotonic volumes. The mechanism underlying osmotic cell volume regulation and its significance are discussed.

Adolescent↗
PubMed1974

Scanning electron microscopy of human lymphocyte-sheep erythrocyte rosettes.

Human lymphocytes of known B or T derivation were examined by scanning electron microscopy (SEM) before and after rosetting with SRBC. After collection of the cells onto silver membranes the samples were prepared for SEM by the critical point drying method. Sheep RBC frequently underwent sphero-echinocyte transformation and multiple projections extended from their surfaces. This was readily noticeable after storage of SRBC in the cold and washing in Hanks, but more prominent after rosetting. These erythrocyte surface alterations were less apparent when freshly withdrawn cells were used. Spontaneous sheep erythrocyte rosettes (E-R), a marker for human T lymphocytes, were prepared with normal peripheral blood lymphocytes (PBL), thymic cells, and cultured T cells. EAC-rosettes (EAC-R), used to identify B lymphocytes with complement receptors, were prepared with normal PBL and cultured B cells. The majority of rosetting T lymphocytes had generally smooth surfaces while about 20% had an intermediate number of microvilli and 15% were more villous and indistinguishable from villous B cells. Studies of rosetting thymocytes and cultured T cells however indicated that the surface of some T cells alters on rosetting, becoming more villous and thus account for the higher numbers of villous T cells seen in E-rosettes. Point to point contact sites between SRBC and T lymphocytes were more frequent than broad zones of attachment. The majority of rosetting B lymphocytes had multiple microvilli, about 25% had a moderate number of microvilli and less than 10% had smooth surfaces similar to those of most T cells. Areas of contact between EAC and B lymphocytes were frequently broad zones of attachment. The study confirms that in many cases B and T lymphocytes can be distinguished by their surface architecture as seen under the SEM; however, about 20% of rosetting B and T cells have similar surfaces with intermediate numbers of surface microvilli and cannot be distinguished by SEM without parallel immunologic identification.

Animals↗
PubMed1974

Analyses of lymphocytes from patients with rheumatoid arthritis and systemic lupus erythematosus. Occurrence of interfering cold-reactive antilymphocyte antibodies.

Large percentages of the lymphocytes from some patients with rheumatoid arthritis and systemic lupus erythematosus were densely covered with Ig demonstrable by immunofluorescence, which was occasionally present in the form of caps. The amount and character of the Ig staining depended largely on the procedures used in the isolation and washing of the lymphocytes. Cold-reactive antilymphocyte antibodies present in many sera wre primarily responsible for these variations. Overnight culture of the lymphocytes proved to be an efficient procedure for the removal of adsorbed antibody. Some evidence was also obtained for the presence of circulating immune complexes and exogenous rheumatoid factor molecules on the lymphocyte surface. Thus on freshly isolated cells the demonstration of surface Ig proved to an unreliable marker of bone marrow-derived (B) cells in these disease: the actual percent of B cells with intrinsic surface Ig was often markedly decreased. In patients with systemic lupus erythematosus, this reduction was in agreement with the low numbers of cells that had a receptor for aggregated IgG. The mean percentage of thymus-derived (T) cells in both diseases was slightly greater than the normal level.The concentrations of lymphocytes in joint fluids from patients with rheumatoid arthritis were often greater than levels found in blood. T cells primarily accounted for this increase. The T cells typically formed unusually dense rosettes with sheep erythrocytes. B lymphocytes were proportionally much diminished. Evidence was obtained for the existence of a major joint fluid lymphocyte population that lacked all assayed surface markers.

Adolescent↗
PubMed1973

Identification of human B and T lymphocytes by scanning electron microscopy.

In this study a variety of human lymphocytes of known B or T cell type, obtained from multiple sources, were prepared for scanning electron microscopy (SEM) by the critical point drying method. Distinction between normal B and T lymphocytes was relatively easy in most instances, on the basis of their surface architecture. Using immunological methods, between 20 and 30% of normal peripheral blood lymphocytes (PBL) were identified as B cells and from 69 to 82% as T cells. SEM results showed that 20% of the PBL had a complex villous surface and approximately 80% of cells were smaller and had a relatively smooth surface. Comparison of the above data and enrichment of B cells from PBL, by centrifugation after T cell rosettes had formed, indicated that the "villous" cells were B lymphocytes and the "relatively smooth" cells were T lymphocytes. T cells obtained from two human thymuses were also of the generally smooth cell type. Further evidence for the distinction of B and T lymphocytes, on the basis of surface morphology, was obtained from the examination of cultured lymphoid cell lines of known B or T cell derivation. Cells from cases of chronic lymphocytic leukemia also provided support for the above interpretations. Five of six untreated cases were clearly of B cell type by immunologic and SEM criteria. One unusual case showed the presence of T and B lymphocytes in almost equal numbers by SEM and a mixture of B and T cells by immunologic markers. An additional case that had received chemotherapy showed numerous atypical cells that were difficult to classify by SEM. Detailed examination of the smoother T cells showed that at least half of them had a moderate number of surface digitations and a small proportion had an intermediate surface morphology with a relatively large number of surface digitations. The latter presented difficulties in classification and may correspond to different stages of differentiation and represent subpopulations of lymphocytes. The distinction between human B and T lymphocytes on the basis of their surface architecture can be made by SEM of critical point dried samples, with relative ease in most but not all instances. The effects of stimulation, cell cycle, differentiation, intercellular contact, and density of cell population, on the surface architecture of lymphoid cells, remain to be determined.

B-Lymphocytes↗
PubMed1973

Sheep red cell binding to human lymphocytes treated with neuraminidase; enhancement of T cell binding and identification of a subpopulation of B cells.

Neuraminidase treatment of normal human lymphocytes enhances their capacity to form SRBC rosettes; more red cells are bound and the rosettes are more stable. Under these conditions approximately 90% of peripheral blood lymphocytes form rosettes. In addition to the effects on T cells, another population of lymphocytes which possess surface immunoglobulin and have the Fc receptor acquire the rosette-forming property after neuraminidase. This subpopulation of 'B' cells represents approximately half of the lymphocytes with surface immunoglobulin but is not found among the leukemic lymphocytes of patients with chronic lymphocytic leukemia. Electron microscope observations indicate close approximation and intimate association of the red cell and lymphocyte membranes after neuraminidase.

Animals↗