Brian L. Pipes

Telomere length changes after umbilical cord blood transplant.

BACKGROUND:  The establishment of donor‐derived hematopoiesis in the recipients of hematopoietic stem cell (HSC) transplants involves extensive proliferation and differentiation of HSCs. Data from long‐term survivors of HSC transplants suggest that these transplanted HSCs may experience a debilitating replicative senescence. A significant posttransplant shortening of peripheral blood mononuclear cell (PBMNC) telomeres has been observed in both marrow transplant and peripheral blood progenitor cell transplant recipients. Similar studies have not been performed for umbilical cord blood (UCB) HSC transplants, which might be expected to exhibit increased posttransplant replicative potential due to their inherently greater telomere length.

Brief heat shock increases stable integration of lipid-mediated DNA transfections

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Studies of a Chloroplast-Localized Small Heat Shock Protein in Arabidopsis

Thermotolerance, or the ability of organisms to withstand exposure to potentially lethal high temperatures, is thought to be conferred by the induction of heat shock proteins (HSPs) (Lindquist 1986). Several major families of HSPs classified according to molecular weight and amino acid similarity have been defined, although how they contribute to the development of thermotolerance is not well understood. Among the HSPs most highly induced by heat stress in eukaryotes is a class of nuclear-encoded proteins ranging in size from 15 to 30 kD referred to as the small HSPs (sHSPs). Though diverse in size and primary structure, the sHSPs can be identified based on their similar hydropathy profiles and homology to the acrystallin proteins of the eye lens (Lindquist and Craig 1988).

Heat-inducible amplifier vector for high-level expression of granulocyte-macrophage colony-stimulating factor

Purpose: In cytokine immunotherapy of cancer it is critical to deliver sufficiently high local cytokine concentrations in order to reach the therapeutic threshold needed for clinical efficacy. Simultaneously, for optimal clinical safety adverse effects caused by high systemic cytokine levels must be minimized. One of the most promising anti-cancer therapeutic cytokines, granulocyte-macrophage colony-stimulating factor (GM-CSF), has elicited anti-tumour immune responses in animal studies and clinical trials. However, the clinical efficacy has been limited, with local GM-CSF levels being therapeutically insufficient and systemic toxicity being a limiting factor. Methods: To address these problems we have developed a novel GM-CSF expression vector, pAD-HotAmp-GM-CSF, which can provide high levels of GM-CSF expression, and induction of cytokine expression to limited tissue areas. This expression system combines inducible and amplifying elements in a single multi-genic construct. The first transcriptional unit contains the inducible element, the heat shock protein 70B (HSP70B) promoter that regulates expression of the transcription-activating factor tat. Results: Upon the binding of tat to the second promoter, the HIV2 long terminal repeat amplifies downstream gene expression of the therapeutic cytokine GM-CSF. Moderate hyperthermia at 42°C for 30 min induced GM-CSF expression in pAD-HotAmp-GM-CSF that was over 2.5- and 2.8-fold higher than levels reached with HSP70B promoter alone and the prototypical human cytomegalovirus promoter. Conclusions: Thus, the inducible amplifier vector, pAD-HotAmp-GM-CSF, represents a novel system for regulated and enhanced GM-CSF expression, which enables both greater efficacy and safety in cytokine immunotherapy of cancer.