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Biomedical subjects

Barjor Gimi

Publications and source records attributed to Barjor Gimi.

5 recordsLinked to original sources
PubMed2006

Noninvasive MRI of endothelial cell response to human breast cancer cells.

We have developed a noninvasive magnetic resonance imaging (MRI) assay to characterize human umbilical vein endothelial cell (HUVEC) motility, invasion, and network formation in response to the presence of cancer cells. HUVECs were labeled with a superparamagnetic iron oxide T(2) contrast agent and cocultured with MDA-MB-231 breast cancer cells in the presence of an extracellular matrix (ECM) gel. Invasion into the ECM gel by HUVECs in response to paracrine factors secreted by MDA-MB-231 cancer cells, as well as network formation by HUVECs, was easily tracked with MRI. The invasive behavior of HUVECs was not observed in the absence of cancer cells. This noninvasive assay used to characterize the response of endothelial cells (ECs) can be used to understand the role of proangiogenic or antiangiogenic stimuli, and to study the interactions between ECs and other disease-specific cells in pathologies with aberrant angiogenesis, such as retinopathy and arthritis.

Adenocarcinoma↗
PubMed2006

Functional MR microimaging of pancreatic beta-cell activation.

The increasing incidence of diabetes and the need to further understand its cellular basis has resulted in the development of new diagnostic and therapeutic techniques. Nonetheless, the quest to noninvasively ascertain beta-cell mass and function has not been achieved. Manganese (Mn)-enhanced MRI is presented here as a tool to image beta-cell functionality in cell culture and isolated islets. Similar to calcium, extracellular Mn was taken up by glucose-activated beta-cells resulting in 200% increase in MRI contrast enhancement, versus nonactivated cells. Similarly, glucose-activated islets showed an increase in MRI contrast up to 45%. Although glucose-stimulated Ca influx was depressed in the presence of 100 microM Mn, no significant effect was seen at lower Mn concentrations. Moreover, islets exposed to Mn showed normal glucose sensitivity and insulin secretion. These results demonstrate a link between image contrast enhancement and beta-cell activation in vitro, and provide the basis for future noninvasive in vivo imaging of islet functionality and beta-cell mass.

Animals↗
PubMed2006

Magnetic resonance microscopy: concepts, challenges, and state-of-the-art.

Recent strides in targeted therapy and regenerative medicine have created a need to identify molecules and metabolic pathways implicated in a disease and its treatment. These molecules and pathways must be discerned at the cellular level to meaningfully reveal the biochemical underpinnings of the disease and to identify key molecular targets for therapy. Magnetic resonance (MR) techniques are well suited for molecular and functional imaging because of their noninvasive nature and their versatility in extracting physiological, biochemical, and functional information over time. However, MR is an insensitive technique; MR microscopy seeks to increase detection sensitivity, thereby localizing biochemical and functional information at the level of single cells or small cellular clusters. Here, we discuss some of the challenges facing MR microscopy and the technical and phenomenological strategies used to overcome these challenges. Some of the applications of MR microscopy are highlighted in this chapter.

Equipment Design↗
PubMed2005

Self-assembled three dimensional radio frequency (RF) shielded containers for cell encapsulation.

This paper describes the construction of three dimensional (3D) encapsulation devices in large numbers, using a novel self-assembling strategy characterized by high mechanical stability, controlled porosity, extreme miniaturization, high reproducibility and the possibility of integrating sensing and actuating electromechanical modules. We demonstrated encapsulation of microbeads and cells within the containers, thereby demonstrating one possible application in cell encapsulation therapy. Magnetic resonance (MR) images of the containers in fluidic media suggest radio frequency (RF) shielding and a susceptibility effect, providing characteristic hypointensity within the container, thereby allowing the containers to be easily detected. This demonstration is the first step toward the design of 3D, micropatterned, non-invasively trackable, encapsulation devices.

Animals↗