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Biomedical subjects

O Pfister

Publications and source records attributed to O Pfister.

6 recordsLinked to original sources
PubMed2001

Polarization instabilities in a two-photon laser.

We describe the operating characteristics of a new type of quantum oscillator that is based on a two-photon stimulated emission process. This two-photon laser consists of spin-polarized and laser-driven 39K atoms placed in a high-finesse transverse-mode-degenerate optical resonator and produces a beam with a power of approximately 0.2 microW at a wavelength of 770 nm. We observe complex dynamical instabilities of the state of polarization of the two-photon laser, which are made possible by the atomic Zeeman degeneracy. We conjecture that the laser could emit polarization-entangled twin beams if this degeneracy is lifted.

Journal Article↗
PubMed2001

Cell-surface trafficking and release of flt3 ligand from T lymphocytes is induced by common cytokine receptor gamma-chain signaling and inhibited by cyclosporin A.

The flt3 ligand (FL) is a growth and differentiation factor for primitive hematopoietic precursors, dendritic cells, and natural killer cells. Human T lymphocytes express FL constitutively, but the cytokine is retained intracellularly within the Golgi complex. FL is mobilized from the cytoplasmic stores and its serum levels are massively increased during the period of bone marrow aplasia after stem cell transplantation (SCT). Signals that trigger the release of FL by T cells remain unknown. This study shows that interleukin (IL)-2, IL-4, IL-7, and IL-15, acting through a common receptor gamma chain (gammac), but not cytokines interacting with other receptor families, are efficient inducers of cell surface expression of membrane-bound FL (mFL) and secretion of soluble FL (sFL) by human peripheral blood T lymphocytes. The gammac-mediated signaling up-regulated FL in a T-cell receptor-independent manner. IL-2 and IL-7 stimulated both FL messenger RNA (mRNA) expression and translocation of FL protein to the cell surface. Cyclosporin A (CsA) inhibited gammac-mediated trafficking of FL at the level of transition from the Golgi to the trans-Golgi network. Accordingly, serum levels of sFL and expression of mFL by T cells of CsA-treated recipients of stem cell allografts were reduced approximately 2-fold (P <.01) compared to patients receiving autologous grafts. The conclusion is that FL expression is controlled by gammac receptor signaling and that CsA interferes with FL release by T cells. The link between gammac-dependent T-cell activation and FL expression might be important for T-cell effector functions in graft acceptance and antitumor immunity after SCT.

Adolescent↗
PubMed2000

Chronic overexpression of membrane-bound flt3 ligand by T lymphocytes in severe aplastic anaemia.

Aplastic anaemia (AA) is an immune-mediated bone marrow failure associated with high serum levels of flt3 ligand (FL). We examined expression of the membrane-bound isoform of FL in peripheral blood and bone marrow cells from AA patients at diagnosis (n = 16) and after immunosuppressive (IS) treatment (n = 36). Flow cytometry demonstrated strongly increased FL levels on the cell surface of T lymphocytes in AA relative to normal controls (P < 0.0001). T-cell-specific expression of membrane-bound FL was confirmed by confocal microscopy. FL mRNA and total cellular FL protein levels were increased about threefold. Overexpression of FL in AA was observed for up to 20 years after IS treatment. FL levels correlated inversely with CD34+ cell numbers and the colony-forming ability of AA bone marrow (R = -0.68 and -0.85 respectively). Histological examination of spleen specimens and bone marrow biopsies gave no evidence of degeneration or fibrosis due to prolonged exposure to high FL. Levels of membrane-bound FL were not increased in autoimmune diseases (n = 23), including rheumatoid arthritis and lupus erythematosus, nor in graft-versus-host disease (n = 8). Chronic overexpression of FL on the surface of T lymphocytes in AA, but not in other T-cell-mediated disorders, suggests that membrane-bound FL plays a role in cell-cell interactions in bone marrow failure and may be important for long-term haemopoietic recovery.

Adolescent↗
PubMed1993

The illusion of a future: a friendly disagreement with Prof. Sigmund Freud.

Freud's The Future of an Illusion was not just an abstract statement of his position on religion, but part of an ongoing exchange of views with Oskar Pfister, a Zurich pastor. Freud was continuing to try to settle differences between himself and Jung. Pfister, while practising as an analyst in 1928, wrote a respectful reply to Freud, and his 'The Illusion of a Future' has never before appeared in English. Pfister was expressing what he saw as the central weaknesses in Freud's attitude toward ethics, art, philosophy, and the practice of psychotherapy.

Austria↗