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Biomedical subjects

X D Yang

Publications and source records attributed to X D Yang.

62 records · Page 4Linked to original sources
PubMed1988

Effect of recombinant human interleukin 4 on spontaneous in vitro human IgE synthesis.

Recombinant human interleukin 4 (IL 4) alone enhanced the spontaneous IgE synthesis in cultures of peripheral blood leukocytes (PBL) from atopic patients as well as from nonatopic individuals, suggesting the existence of preactivated PBL sensitive for IL 4. Preactivated cells were also obtained by stimulation with Staphylococcus aureus strain Cowan I (SAC). However, co-stimulation of PBL by IL 4 with SAC or anti-IgM antibody and pokeweed mitogen did not result in an enhanced IgE synthesis. Optimal IL 4 concentrations for the induction of IgE synthesis coincided with optimal proliferative responses in PBL. The effect of IL 4 was not isotype specific, and in terms of protein even more IgG and IgM antibodies were formed. The effect of IL 4 on IgE synthesis was counteracted by very low concentrations of interferon-gamma (IFN-gamma), suggesting that both IL 4 and IFN-gamma might be decisive cytokines for the human in vitro IgE synthesis.

Cells, Cultured↗
PubMed1987

Human T hybridoma-derived immunoglobulin-binding factors.

A human T hybridoma was generated lacking demonstrable low-affinity IgE surface receptors. This cell line produces spontaneously immunoglobulin-binding factors. The factors have an affinity for human IgE and IgG as well as for IgG from other species. The binding factors were purified by concanavalin A affinity chromatography, an IgE immunoaffinity column and SDS-PAGE. This purification procedure resulted in five major proteins bands at 13, 15, 30, 60 and less than 150 kilodaltons. As judged by Western blot analysis, all bands were variably glycosylated and were capable of binding IgE. Biological activity resided even within the small molecular weight (13 kilodaltons) peptide in terms of inhibiting IgE synthesis of the U266 B cell line and net IgE synthesis of B cells from atopic blood donors. Additionally, semipurified binding factor preparations also inhibited the Pokeweed mitogen-induced IgG synthesis while stimulating IgE synthesis at the same time. At present it is not clear whether the different molecular entities are dimers or polymers of the same protein, or are all derived from one larger protein (proteolytically cleaved), or whether they are completely different peptides mediating similar immunoglobulin-binding capacities as well as similar biological activities. Glycosylation of binding factors is not responsible for binding to immunoglobulins, but might be important for its biological activity.

Antibody Formation↗
PubMed1987

A neuronal network model of associative memory and a brain theory.

There are facts suggesting that the changes of excitability of neurons and conductance of synapses are responsible for learning and memory. In accordance with the idea, the author proposed a neuronal network model of associative memory, which can learn conditioned reflexes repeatedly together with its adaptive properties, without much interference with the previously existing memories. Further, a modified model can memorize dynamic images and establish motor patterns. An analysis of the structure of the model is presented, and some conclusions about this sort of model are drawn. A theory of memory and learning suggesting that the brain works by means of a mechanism similar to that of the model is proposed, as well as the explanations for some behavioral and clinical findings from the viewpoint of the model.

Animals↗