Theoretical analysis of the mechanisms of a gender differentiation in the propensity for orthostatic intolerance after spaceflight

Background  

A tendency to develop reentry orthostasis after a prolonged exposure to microgravity is a common problem among astronauts. The problem is 5 times more prevalent in female astronauts as compared to their male counterparts. The mechanisms responsible for this gender differentiation are poorly understood despite many detailed and complex investigations directed toward an analysis of the physiologic control systems involved.     

Simulated Microgravity Using a Rotary Culture System Compromises the In Vitro Development of Mouse Preantral Follicles

Background

Growing cells in simulated weightlessness condition might be a highly promising new technique to maintain or generate tissue constructs in a scaffold-free manner. There is limited evidence that microgravity condition may affect development of ovarian follicles. The objective of the present study was to investigate the effects of simulated microgravity on the in vitro development of mouse preantral follicles.

Methods and Results

Ovarian tissue from 14-day-old mice, or preantral follicles mechanically isolated from 14-day-old mouse ovaries were cultured at a simulated microgravity condition generated using a rotating wall vessel apparatus. Follicle survival was assessed quantitatively using H&E staining. Follicle diameter and oocyte diameter were measured under an inverted microscope. Ultrastructure of oocytes was evaluated using transmission electron microscopy. We observed that simulated microgravity compromised follicle survival in vitro, downregulated PCNA and GDF-9 expressions, and caused ultrastructural abnormalities in oocytes.

Conclusion

This study showed for the first time that three-dimensional culture condition generated by simulated microgravity is detrimental to the initial stage development of mouse preantral follicles in vitro. The experimental setup provides a model to further investigate the mechanisms involved in the in vitro developmental processes of oocytes/granulosa cells under the microgravity condition.     

Changes in gravitational force affect gene expression in developing organ systems at different developmental times

Background  

Little is known about the affect of microgravity on gene expression, particularly in vivo during embryonic development. Using transgenic zebrafish that express the gfp gene under the influence of a β-actin promoter, we examined the affect of simulated-microgravity on GFP expression in the heart, notochord, eye, somites, and rohon beard neurons. We exposed transgenic zebrafish to simulated-microgravity for different durations at a variety of developmental times in an attempt to determine periods of susceptibility for the different developing organ systems.     

Effect of Simulated Microgravity on Human Brain Gray Matter and White Matter – Evidence from MRI

Background

There is limited and inconclusive evidence that space environment, especially microgravity condition, may affect microstructure of human brain. This experiment hypothesized that there would be modifications in gray matter (GM) and white matter (WM) of the brain due to microgravity.

Method

Eighteen male volunteers were recruited and fourteen volunteers underwent -6° head-down bed rest (HDBR) for 30 days simulated microgravity. High-resolution brain anatomical imaging data and diffusion tensor imaging images were collected on a 3T MR system before and after HDBR. We applied voxel-based morphometry and tract-based spatial statistics analysis to investigate the structural changes in GM and WM of brain.

Results

We observed significant decreases of GM volume in the bilateral frontal lobes, temporal poles, parahippocampal gyrus, insula and right hippocampus, and increases of GM volume in the vermis, bilateral paracentral lobule, right precuneus gyrus, left precentral gyrus and left postcentral gyrus after HDBR. Fractional anisotropy (FA) changes were also observed in multiple WM tracts.

Conclusion

These regions showing GM changes are closely associated with the functional domains of performance, locomotion, learning, memory and coordination. Regional WM alterations may be related to brain function decline and adaption. Our findings provide the neuroanatomical evidence of brain dysfunction or plasticity in microgravity condition and a deeper insight into the cerebral mechanisms in microgravity condition.     

LIF-Free Embryonic Stem Cell Culture in Simulated Microgravity

Background

Leukemia inhibitory factor (LIF) is an indispensable factor for maintaining mouse embryonic stem (ES) cell pluripotency. A feeder layer and serum are also needed to maintain an undifferentiated state, however, such animal derived materials need to be eliminated for clinical applications. Therefore, a more reliable ES cell culture technique is required.

Methodology/Principal Findings

We cultured mouse ES cells in simulated microgravity using a 3D-clinostat. We used feeder-free and serum-free media without LIF.

Conclusions/Significance

Here we show that simulated microgravity allows novel LIF-free and animal derived material-free culture methods for mouse ES cells.     

Effect of microgravity on proliferation and differentiation of embryonic stem cells in an automated culturing system during the TZ‐1 space mission

Objective

Despite a great number of studies analysing the effects of microgravity on stem cell proliferation and differentiation, few of them have focused on real‐time imaging estimates in space. Herein, we utilized the TZ‐1 cargo spacecraft, automatic cell culture equipment and live cell imaging techniques to examine the effects of real microgravity on the proliferation and differentiation of mouse embryonic stem cells (mESCs).

Materials and methods

Oct4‐GFP, Brachyury‐GFP mESC and Oct4‐GFP mESC‐derived EBs were used as experimental samples in the TZ‐1 spaceflight mission. These samples were seeded into chambers, cultured in an automatic cell culture device and were transported into space during the TZ‐1 mission. Over 15 days of spaceflight, bright field and fluorescent images of cell growth were taken in micrography, and the medium was changed every day. Real‐time image data were transferred to the ground for analysis.

Results

Space microgravity maintains stemness and long‐term survival of mESCs, promising 3D aggregate formation. Although microgravity did not significantly prevent the migration of EBs on the ECM substrate, it did prevent terminal differentiation of cells.

Conclusions

This study demonstrates that space microgravity might play a potential role in supporting 3D cell growth and maintenance of stemness in embryonic stem cells, while it may negatively affect terminal differentiation.

     

Novel biomarkers predict liver fibrosis in hepatitis C patients: alpha 2 macroglobulin,vitamin D binding protein and apolipoprotein AI

Background  

The gold standard of assessing liver fibrosis is liver biopsy, which is invasive and not without risk. Therefore, searching for noninvasive serologic biomarkers for liver fibrosis is an importantly clinical issue.     

Statistical distributions of optimal global alignment scores of random protein sequences

Background  

The inference of homology from statistically significant sequence similarity is a central issue in sequence alignments. So far the statistical distribution function underlying the optimal global alignments has not been completely determined.     

Identification of putative domain linkers by a neural network – application to a large sequence database

Background  

The reliable dissection of large proteins into structural domains represents an important issue for structural genomics/proteomics projects. To provide a practical approach to this issue, we tested the ability of neural network to identify domain linkers from the SWISSPROT database (101602 sequences).     

Classification of the extracellular fields produced by activated neural structures

Background  

Classifying the types of extracellular potentials recorded when neural structures are activated is an important component in understanding nerve pathophysiology. Varying definitions and approaches to understanding the factors that influence the potentials recorded during neural activity have made this issue complex.     

Complexity of MRI induced heating on metallic leads: Experimental measurements of 374 configurations

Background  

MRI induced heating on PM leads is a very complex issue. The widely varying results described in literature suggest that there are many factors that influence the degree of heating and that not always are adequately addressed by existing testing methods.     

Evolutionary dynamics of a conserved sequence motif in the ribosomal genes of the ciliate <Emphasis Type="Italic">Paramecium</Emphasis>

Background  

In protozoa, the identification of preserved motifs by comparative genomics is often impeded by difficulties to generate reliable alignments for non-coding sequences. Moreover, the evolutionary dynamics of regulatory elements in 3' untranslated regions (both in protozoa and metazoa) remains a virtually unexplored issue.     

Carton for beverage—A decade of process efficiency improvements enhancing its environmental profile

Purpose  

Chain efficiency is currently a key issue for evaluating the sustainability of products and processes. Thus, the objective of this study was to evaluate how the overall efficiency process improvement carried out in the upstream manufacturing chain of LPB (Liquid Packaging Board) has affected the environmental profile over the last 10 years.     

A hierarchical Bayesian network approach for linkage disequilibrium modeling and data-dimensionality reduction prior to genome-wide association studies

Background  

Discovering the genetic basis of common genetic diseases in the human genome represents a public health issue. However, the dimensionality of the genetic data (up to 1 million genetic markers) and its complexity make the statistical analysis a challenging task.     

Quality assessment of microarrays: Visualization of spatial artifacts and quantitation of regional biases

Background  

Quality-control is an important issue in the analysis of gene expression microarrays. One type of problem is regional bias, in which one region of a chip shows artifactually high or low intensities (or ratios in a two-channel array) relative to the majority of the chip. Current practice in quality assessment for microarrays does not address regional biases.     

So what do we really mean when we say that systems biology is <Emphasis Type="Italic">holistic</Emphasis>?

Background  

An old debate has undergone a resurgence in systems biology: that of reductionism versus holism. At least 35 articles in the systems biology literature since 2003 have touched on this issue. The histories of holism and reductionism in the philosophy of biology are reviewed, and the current debate in systems biology is placed in context.