Three-dimensional perfusion bioreactor culture supports differentiation of human fetal liver cells.

The ability of human fetal liver cells to survive, expand, and form functional tissue in vitro is of high interest for the development of bioartificial extracorporeal liver support systems, liver cell transplantation therapies, and pharmacologic models. Conventional static two-dimensional culture models seem to be inadequate tools. We focus on dynamic three-dimensional perfusion technologies and developed a scaled-down bioreactor, providing decentralized mass exchange with integral oxygenation.

Phase transformation behaviour of hydroxyapatite foams subject to heat treatment.

This study examined the relationship between sintering and phase transformation behaviour in hydroxyapatite (HA). Pellets and replicated foams were sintered at five different temperatures ranging from 1350 degrees C to 1550 degrees C. Hydroxyapatite remained as the major phase in all the samples studied.

Plasmonic activity of large-area gold nanodot arrays on arbitrary substrates.

Highly efficient fabrication of well-ordered, embedded gold nanodot matrices using diffraction mask projection laser ablation is demonstrated. These gold nanodot arrays are ideally generated onto sapphire substrates but do also form onto AlO(x) thin films, enabling the application to arbitrary bulk substrates. Well-ordered gold dots become embedded into the Al(2)O(3) substrate during the process, thus improving their mechanical stability, chemical inertness, and technological compliance.

Hepatic maturation of human fetal hepatocytes in four-compartment three-dimensional perfusion culture.

Bio-artificial liver support systems have been utilized as bridging devices to support acute and chronic liver injury. However, prolonged function of adult hepatocytes has not been achieved due to compromised proliferation and long-term survival of adult cells in vitro. As an alternative cell source, we investigated the potential of human fetal hepatocytes (hFH) in a four-compartment hollow fiber-based three-dimensional (3D) perfusion culture system.

The nitric oxide donor S-nitrosoglutathione reduces apoptotic primary liver cell loss in a three-dimensional perfusion bioreactor culture model developed for liver support.

Introduction: Artificial extracorporeal support for hepatic failure has met with limited clinical success. In hepatocytes, nitric oxide (NO) functions as an antiapoptotic modulator in response to a variety of stresses. We hypothesized that NO administration would yield improved viability and hepatocellular restructuring in a four-compartment, hollow fiber-based bioreactor with integral oxygenation for dynamic three-dimensional perfusion of hepatic cells in bioartificial liver support systems.

Electrospray ion beam deposition: soft-landing and fragmentation of functional molecules at solid surfaces.

The ion beam deposition (IBD) of rhodamine dye molecules on solid surfaces in high vacuum is explored in order to characterize the possibility of fabricating molecular coatings or nanostructures from nonvolatile molecules. Molecular ion beams with a well-defined composition are deposited on silicon oxide surfaces with a controlled kinetic energy. Photoluminescence spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) are employed in order to characterize the sample with respect to coverage, homogeneity, and the fraction of intact landed ions (soft-landing ratio).

Automated quality control for segmentation of myocardial perfusion SPECT.

Unlabelled: Left ventricular (LV) segmentation, including accurate assignment of LV contours, is essential for the quantitative assessment of myocardial perfusion SPECT (MPS). Two major types of segmentation failures are observed in clinical practices: incorrect LV shape determination and incorrect valve-plane (VP) positioning. We have developed a technique to automatically detect these failures for both nongated and gated studies.

FOXP3 expression in hepatitis C virus-specific CD4+ T cells during acute hepatitis C.

Background & Aims: Down-regulation of hepatitis C virus (HCV)-specific CD4(+) T-cell responses is a hallmark of chronic viral persistence in acute hepatitis C. FOXP3(+)CD25(+)CD4(+) regulatory T cells can modulate HCV-specific immune responses in vitro, but the role of virus-specific regulatory T cells in the pathogenesis of chronic viral persistence is unknown.

Methods: Two novel HLA-DR15 tetramers were synthesized to study the kinetics and phenotype of FOXP3(+)-expressing HCV-specific CD4(+) T cells from 10 patients with acute hepatitis C and 15 patients with chronic hepatitis C.

The Characterization Tool: A knowledge-based stem cell, differentiated cell, and tissue database with a web-based analysis front-end.

In the rapidly growing field of stem cell research, there is a need for universal databases and web-based applications that provide a common knowledge base on the characteristics of stem cells, differentiated cells, and tissues by collecting, processing, and making available diverse types of characterization data. The Characterization Tool is such a novel knowledge database that allows the storage of various characteristics of cells, cell lines, and tissues across different species as well as the analysis of associated marker profiles. Its broad ontology-based framework facilitates the integration of characterization data on the morphological, molecular, and functional level acquired in vivo and in vitro including published marker expressions, cross-references to other databases, text descriptions, information on characterization experiments, and image storage.

Species-wide genetic variation and demographic history of Drosophila sechellia, a species lacking population structure.

Long-term persistence of species characterized by a reduced effective population size is still a matter of debate that would benefit from the description of new relevant biological models. The island endemic specialist Drosophila sechellia has received considerable attention in evolutionary genetic studies. On the basis of the analysis of a limited number of strains, a handful of studies have reported a strikingly depleted level of genetic variation but little is known about its demographic history.

Quantitative comparison of stem cell marker-positive cells in fetal and term human amnion.

Scattered in the amniotic epithelium of the human term placenta are pluripotent stem cell marker-positive cells. Unlike other parts of the placenta, amniotic epithelial (AE) cells are derived from pluripotent epiblasts. It is hypothesized that most epiblast-derived fetal AE cells are positive for stem cell markers at the beginning of pregnancy and that the stem cell marker-positive cells scattered through the term amnion are remaining, epiblast-like stem cells.

Transport advances in disposable bioreactors for liver tissue engineering.

Acute liver failure (ALF) is a devastating diagnosis with an overall survival of approximately 60%. Liver transplantation is the therapy of choice for ALF patients but is limited by the scarce availability of donor organs. The prognosis of ALF patients may improve if essential liver functions are restored during liver failure by means of auxiliary methods because liver tissue has the capability to regenerate and heal.

Exploring the relationship between faculty, students, and the Social and Behavioral Ethics Review Committee through action research.

STUDENT RESEARCHERS USED ACTION research both to study the relationship between university researchers and the ethics committee, and also to explore the ethics committee's approach to protocols involving action research and other qualitative methods. We review the existing literature on relationships between university faculty and their ethics committees and briefly discuss the basic tenets of action research. We then describe our research process and the specific recommendations that resulted from this work.

Dynamic 3D culture promotes spontaneous embryonic stem cell differentiation in vitro.

Spontaneous in vitro differentiation of mouse embryonic stem cells (mESC) is promoted by a dynamic, three-dimensional (3D), tissue-density perfusion technique with continuous medium perfusion and exchange in a novel four-compartment, interwoven capillary bioreactor. We compared ectodermal, endodermal, and mesodermal immunoreactive tissue structures formed by mESC at culture day 10 with mouse fetal tissue development at gestational day E9.5.

Effect of human patient plasma ex vivo treatment on gene expression and progenitor cell activation of primary human liver cells in multi-compartment 3D perfusion bioreactors for extra-corporeal liver support.

Cultivation of primary human liver cells in innovative 3D perfusion multi-compartment capillary membrane bioreactors using decentralized mass exchange and integral oxygenation provides in vitro conditions close to the physiologic environment in vivo. While a few scale-up bioreactors were used clinically, inoculated liver progenitors in these bioreactors were not investigated. Therefore, we characterized regenerative processes and expression patterns of auto- and paracrine mediators involved in liver regeneration in bioreactors after patient treatment.

Myocardial wall thickening from gated Magnetic Resonance images using Laplace's equation.

The aim of our work is to present a robust 3D automated method for measuring regional myocardial thickening using cardiac magnetic resonance imaging (MRI) based on Laplace's equation. Multiple slices of the myocardium in short-axis orientation at end-diastolic and end-systolic phases were considered for this analysis. Automatically assigned 3D epicardial and endocardial boundaries were fitted to short-axis and long axis slices corrected for breathold related misregistration, and final boundaries were edited by a cardiologist if required.

Quantitative assessment of myocardial perfusion abnormality on SPECT myocardial perfusion imaging is more reproducible than expert visual analysis.

Background: Current guidelines of Food and Drug Administration for the evaluation of SPECT myocardial perfusion imaging (MPI) in clinical trials recommend independent visual interpretation by multiple experts. Few studies have addressed whether quantitative SPECT MPI assessment would be more reproducible for this application.

Methods And Results: We studied 31 patients (age 68 +/- 13, 25 male) with abnormal stress MPI who underwent repeat exercise (n = 11) or adenosine (n = 20) MPI within 9-22 months (mean 14.

Peptide modification of polyethersulfone surfaces to improve adipose-derived stem cell adhesion.

Polyethersulfone (PES) is a nondegradable, biocompatible, synthetic polymer that is commonly utilized as a membrane material for applications such as hemodialysis, ultrafiltration and bioreactor technology. Various studies have shown surface modification to be a valuable tool in the development of nondegradable materials which promote cell adhesion. Cells of interest include adipose-derived stem cells (ASCs).

Isolation and characterization of adult human liver progenitors from ischemic liver tissue derived from therapeutic hepatectomies.

Recent evidence suggests that progenitor cells in adult tissues and embryonic stem cells share a high resistance to hypoxia and ischemic stress. To study the ischemic resistance of adult liver progenitors, we characterized remaining viable cells in human liver tissue after cold ischemic treatment for 24-168 h, applied to the tissue before cell isolation. In vitro cultures of isolated cells showed a rapid decline of the number of different cell types with increasing ischemia length.

Towards non- and minimally instrumented, microfluidics-based diagnostic devices.

In many health care settings, it is uneconomical, impractical, or unaffordable to maintain and access a fully equipped diagnostics laboratory. Examples include home health care, developing-country health care, and emergency situations in which first responders are dealing with pandemics or biowarfare agent release. In those settings, fully disposable diagnostic devices that require no instrument support, reagent, or significant training are well suited.

Evaluation and optimization of hepatocyte culture media factors by design of experiments (DoE) methodology.

Optimization of cell culture media based on statistical experimental design methodology is a widely used approach for improving cultivation conditions. We applied this methodology to refine the composition of an established culture medium for growth of a human hepatoma cell line, C3A. A selection of growth factors and nutrient supplements were systematically screened according to standard design of experiments (DoE) procedures.

Development of a European human embryonic stem cell registry.

The number of human embryonic stem cell (hESC) lines that are available and that are subsequently being used in numerous research projects is increasing steadily. However, there is little coordination of hESC line derivation, and comparative information on the characteristics and quality of these cells is sparse. Obtaining consistent information on hESCs is hampered further by legislative fragmentation, particularly in Europe.

Ion-beam-induced collective rotation of nanocrystals.

Vapor-deposited nanocrystalline titanium layers have been irradiated at room temperature with 350-MeV-Au ions up to 4x10;{15} Au/cm;{2}. Bombardment-induced texture changes were determined at the BESSY synchrotron light source. During off-normal irradiation, the nanocrystals undergo grain alignment and rotation up to approximately 90 degrees at the highest ion fluence.

Acute hepatitis C: current status and remaining challenges.

The acute phase of hepatitis C virus (HCV) infection represents a key point in the evolution of hepatitis C. In some patients, the infection resolves spontaneously, whereas in others it develops into chronic disease. However, because acute hepatitis C is often asymptomatic, detection and diagnosis are usually difficult.