Freeform Bioprinting of Liver Encapsulated in Alginate Hydrogels Tissue Constructs for Pharmacokinetic Study

An in vitro model that can be realistically and inexpensively used to predict human response to various drug administration and toxic chemical exposure is needed. By fabricating a microscale 3D physiological tissue construct consisting of an array of channels and tissue-embedded chambers, one can selectively develop various biomimicking mammalian tissues for a number of pharmaceutical applications, for example, experimental pharmaceutical screening for drug efficacy and toxicity along with apprehending the disposition and metabolic profile of a candidate drug. This paper addresses issues relating to the development and implementation of a bioprinting process for freeform fabrication of a 3D cell-encapsulated hydrogel-based tissue construct, the direct integration onto a microfluidic device for pharmacokinetic study, and the underlying engineering science for the fabrication of a 3D microscale tissue chamber as well as its application in pharmacokinetic study. To this end, a prototype 3D microfluidic tissue chamber embedded with liver cells encapsulated within a hydrogel matrix construct is bioprinted as a physiological in vitro model for pharmacokinetic study. The developed fabrication processes are further validated and parameters optimized by assessing cell viability and liver cell phenotype, in which metabolic and synthetic liver functions are quantitated.Mechanical Engineerin

Affective adaptation = effective transformation? Shifting the politics of climate change adaptation and transformation from the status quo

Alarming rates of environmental change have catalyzed scholars to call for fundamental transformations in social-political and economic relations. Yet cautionary tales about how power and politics are constitutive of these efforts fill the literature. We show how a relational framing of adaptation and transformation demands a political, cross-scalar, and socionatural analysis to probe the affects and effects of climate change and better grasp how transformative change unfolds. We bring affect theory into conversation with the literature on adaptation politics, socio-environmental transformations, subjectivity, and our empirical work to frame our analysis around three under investigated aspects of transformation: (i) the uncertain and unpredictable relations that constitute socionatures; (ii) other ways of knowing; and (iii) the affective and emotional relations that form a basis for action. Affective adaptation represents a different ontological take on transformation by reframing the socionatural, normative and ethical aspects as relational, uncertain, and performative. This directs analytical attention to processes rather than outcomes. The emphasis on the encounter between bodies in affect theory points to the need for experiential and embodied ways of knowing climate to effect transformative change. Effective transformation requires recognizing uncertainty and unpredictability as part of transformative processes. This is not because all outcomes are acceptable, but rather because uncertainty and unpredictability are elements which help generate affects (action) and emotional commitment to shared human and more than human relations in action, projects, and policies. This article is categorized under: Vulnerability and Adaptation to Climate Change > Values-Based Approach to Vulnerability and Adaptatio

TEACHER´S DIDACTIC COMPETENCIES WHEN TEACHING NATURAL SCIENCE SUBJECTS AS A LEARNING ENVIRONMENT FACTOR

The relationship of primary and secondary schools pupils to natural science subjects is often discussed together with teacher´s didactic competencies that are implemented when teaching natural science subjects. The aim of the paper is to find out how pupils from chosen primary and secondary schools in the Slovak Republic evaluate didactic competencies of natural science subjects teachers in the framework of the overall learning environment evaluation of these subjects. The means to fulfil this objective is the analysis of corresponding questionnaire items oriented on the learning environment when teaching natural science subjects. A partial aim is to compare the evaluation of natural science teachers didactic competencies from several points of view: school type (at primary and secondary schools), gender issues (boys and girls), in relation to the overall learning environment and in relation to learning environment at primary and secondary schools.  Article visualizations

Three-Dimensional Transgenic Cell Models to Quantify Space Genotoxic Effects

In this paper we describe a three-dimensional, multicellular tissue-equivalent model, produced in NASA-designed, rotating wall bioreactors using mammalian cells engineered for genomic containment of mUltiple copies of defined target genes for genotoxic assessment. The Rat 2(lambda) fibroblasts (Stratagene, Inc.) were genetically engineered to contain high-density target genes for mutagenesis. Stable three-dimensional, multicellular spheroids were formed when human mammary epithelial cells and Rat 2(lambda) fibroblasts were cocultured on Cytodex 3 Beads in a rotating wall bioreactor. The utility of this spheroidal model for genotoxic assessment was indicated by a linear dose response curve and by results of gene sequence analysis of mutant clones from 400micron diameter spheroids following low-dose, high-energy, neon radiation exposur

Comparison of Genotoxic Damage in Monolayer Cell Cultures and Three-Dimensional Tissue-Like Cell Assemblies

Assessing the biological risks associated with exposure to the high-energy charged particles encountered in space is essential for the success of long-term space exploration. Although prokaryotic and eukaryotic cell models developed in our laboratory and others have advanced our understanding of many aspects of genotoxicity, in vitro models are needed to assess the risk to humans from space radiation insults. Such models must be representative of the cellular interactions present in tissues and capable of quantifying I genotoxic damage. Toward this overall goal, the objectives of this study were to examine the effect of the localized microenvironment of cells, cultured as either 2-dimensional (2D) monolayers or 3-dimensional (3D) aggregates, on the rate and type of genotoxic damage resulting from exposure to iron charged particles, a significant portion of space radiation. We used rodent transgenic cell lines containing 50-70 copies of a LacI transgene to provide the enhanced sensitivity required to quantify mutational frequency and type in the 1,100-bp LacI target as well as assessment of DNA,damage to the entire 45-kbp construct. Cultured cells were exposed to high-ener~ir on charged particles at Brookhaven National Laboratory s Alternating Gradient Synchrotron facility for a total dose of 0, 0.1, 0.25,0.5, 1.0, or 2.0 Gy and allowed to recover for 0, 1, or 7 days, after which mutational type and frequency were evaluated. The mutational frequency was found to be higher in 3D samples than in 2D samples at all radiation doses. Mutational frequency also was higher at 7 days after irradiation than immediately after exposure. DNA sequencing of the mutant targets revealed that deletional mutations contributed an increasingly high percentage (up to 27%) of all mutations in cells as the dose was increased from 0.5 to 2 Gy. Several mutants also showed large and complex deletions in multiple locations within the Lac1 target. However, no differences in mutational type were found between the 2D and the 3D samples. These 3D tissue-like model systems can reduce the uncertainty involved in extrapolating risk between in vitro cellular and in vivo models

Inhaled Liposomal Ciprofloxacin Nanoparticles Control the Release of Antibiotic at the Bronchial Epithelia

The cycle of respiratory tract infection (RTI) and inflammation in patients with chronic obstructive lung diseases, such as cystic fibrosis (CF), periodically develops into exacerbations, where chronic colonization of the airway by bacteria causes severe decline in lung function, leading to increased hospitalization and high mortality rates (1, 2). Current antibiotic inhalation treatments approved for the management of chronic airway infections in cystic fibrosis are limited to tobramycin (TOBI®) and more recently, aztreonam (Cayston®). A major drawback to these localized treatments of RTIs is the rapid absorption and clearance of antibiotics from the lungs requiring multiple daily inhalations of high concentration antibiotic solutions. Hence, liposomal ciprofloxacin nanoparticles were developed to prolong lung residence time of the antibiotics, with the view to enhance antimicrobial activity and reduce the burden of therapy for the patients and their relatives who often have to assist them. Although in vivo studies with aerosolized delivery of liposomal ciprofloxacin have previously been performed on human and animal subjects, in vitro cell models may be better suited to study the transport, interactions of drugs and carrier systems, and drug localization within and on the airway cell epithelium at a molecular level. Therefore, the aim of this study was to investigate the newly developed system allowing nebulized liposomal ciprofloxacin to be delivered directly to the bronchial epithelial surface in an established air interface Calu-3 cell model

Identification of Genes Associated with Water Restriction Expressed in the Renal Cortex and Hypothalamus in Cattle

The short-term objective of this study is to discover genes associated with water restriction expressed in the renal cortex and hypothalamus in beef calves. The long-term goal is to understand genes and pathways important for thirst response in cattle. This knowledge may lead to discovery of genetic variants associated with water intake. Identification of animals with genetic potential to grow and thrive under drought conditions would be an asset to beef producers and communities which rely on beef production for a large part of their livelihoods. Both selected tissue types are known to be involved in response to hypertonicity (e.g., water restriction or dehydration)

Coronary fly-through or virtual angioscopy using dual-source MDCT data

Coronary fly-through or virtual angioscopy (VA) has been studied ever since its invention in 2000. However, application was limited because it requires an optimal computed tomography (CT) scan and time-consuming post-processing. Recent advances in post-processing software facilitate easy construction of VA, but until now image quality was insufficient in most patients. The introduction of dual-source multidetector CT (MDCT) could enable VA in all patients. Twenty patients were scanned using a dual-source MDCT (Definition, Siemens, Forchheim, Germany) using a standard coronary artery protocol. Post-processing was performed on an Aquarius Workstation (TeraRecon, San Mateo, Calif.). Length travelled per major branch was recorded in millimetres, together with the time required in minutes. VA could be performed in every patient for each of the major coronary arteries. The mean (range) length of the automated fly-through was 80 (32–107) mm for the left anterior descending (LAD), 75 (21–116) mm for the left circumflex artery (LCx), and 109 (21–190) mm for the right coronary artery (RCA). Calcifications and stenoses were visualised, as well as most side branches. The mean time required was 3 min for LAD, 2.5 min for LCx, and 2 min for the RCA. Dual-source MDCT allows for high quality visualisation of the coronary arteries in every patient because scanning with this machine is independent of the heart rate. This is clearly shown by the successful VA in all patients. Potential clinical value of VA should be determined in the near future