Tissue engineered, biomimetic acellular matrices for expansion of hematopoietic progenitors

This thesis discusses a novel strategy for ex vivo expansion of human HSPC in a cell free culture system and it suggests methods to improve the functional properties of stromal cell derived ACMs to support ex-vivo HSPC growth.

A new interpolation error expansion based reversible watermarking algorithm considering the human visual system

Reversible watermarking has merged over the past few years as a promising solution for copyright protection, especially for applications like remote sensing, medical imaging and military applications which require lossless recovery of the host media. In this paper, we aim to extend the additive interpolation error expansion technique in [16]. We will consider the human visual system (HVS) to improve the embedding rate while maintaining the image visual quality. To this end, the just noticeable difference (JND) is used to embed more watermark bits. The experimental results show that the proposed algorithm can improve the embedding rate while preserving the image visual quality. © 2014 IEEE.

Expansion of human hematopoietic stem/progenitor cells on decellularized matrix scaffolds

Umbilical cord blood (UCB) is one of the richest sources for hematopoietic stem/progenitor cells (HSPCs), with more than 3000 transplantations performed each year for the treatment of leukemia and other bone marrow, immunological, and hereditary diseases. However, transplantation of single cord blood units is mostly restricted to children, due to the limited number of HSPC per unit. This unit develops a method to increase the number of HSPCs in laboratory conditions by using cell-free matrices from bone marrow cells that mimic 'human-body niche-like' conditions as biological scaffolds to support the ex vivo expansion of HSPCs. In this unit, we describe protocols for the isolation and characterization of HSPCs from UCB and their serum-free expansion on decellularized matrices. This method may also help to provide understanding of the biochemical organization of hematopoietic niches and lead to suggestions regarding the design of tissue engineering-based biomimetic scaffolds for HSPC expansion for clinical applications.

Cryo-electron microscopy and single molecule fluorescent microscopy detect CD4 receptor induced HIV size expansion prior to cell entry

Viruses are often thought to have static structure, and they only remodel after the viruses have entered target cells. Here, we detected a size expansion of virus particles prior to viral entry using cryo-electron microscopy (cryo-EM) and single molecule fluorescence imaging. HIV expanded both under cell-free conditions with soluble receptor CD4 (sCD4) targeting the CD4 binding site on the HIV-1 envelope protein (Env) and when HIV binds to receptor on cellular membrane. We have shown that the HIV Env is needed to facilitate receptor induced virus size expansions, showing that the 'lynchpin' for size expansion is highly specific. We demonstrate that the size expansion required maturation of HIV and an internal capsid core with wild type stability, suggesting that different HIV compartments are linked and are involved in remodelling. Our work reveals a previously unknown event in HIV entry, and we propose that this pre-entry priming process enables HIV particles to facilitate the subsequent steps in infection.