A working hypothesis visualization method for fNIRS measurements using Monte Carlo simulation.

In neuroscience, clarifying the functional localization of the cerebrum using functional near-infrared spectroscopy (fNIRS) is one of the important works. To better understand and trust fNIRS data, neuroscientists formulate hypothesis about the underlying neural processes. However, visualizing and validating these hypotheses is not easy due to the complex nature of brain activity and the limitations of fNIRS measurements.

Monte Carlo Modeling of Shortwave-Infrared Fluorescence Photon Migration in Voxelized Media for the Detection of Breast Cancer.

Recent progress regarding shortwave-infrared (SWIR) molecular imaging technology has inspired another modality of noninvasive diagnosis for early breast cancer detection in which previous mammography or sonography would be compensated. Although a SWIR fluorescence image of a small breast cancer of several millimeters was obtained from experiments with small animals, detailed numerical analyses before clinical application were required, since various parameters such as size as well as body hair differed between humans and small experimental animals. In this study, the feasibility of SWIR was compared against visible (VIS) and near-infrared (NIR) region, using the Monte Carlo simulation in voxelized media.

Optimal focus evaluated using Monte Carlo simulation in non-invasive neuroimaging in the second near-infrared window.

Adjusting the focal plane through the intact scalp of mice is crucial in novel angiography of cerebral vasculature using quantum dots emitting second near-infrared light at a wavelength of 1100 nm. Reagents were administered through the caudal vein. When we focused 0.

Near infrared imaging of intrinsic signals in cortical spreading depression observed through the intact scalp in hairless mice.

Brain cooling was inevitable in both thinned and intact skull windows in neuroimaging in vivo of mice. Thus we proposed the novel imaging method leaving intact scalp on the skull using the light at 670, 785, and 975 nm. In this study, we used hairless mice (Hos:HR-1) since the deterioration of image quality was resulted from the hair.

Direct quantification of mitochondria and mitochondrial DNA dynamics.

Mitochondria are known to be one of major organelles within a cell and to play a crucial role in many cellular functions. These organelles show the dynamic behaviors such as fusion, fission and the movement along cytoskeletal tracks. Besides mitochondria, mitochondrial DNA is also highly motile.

Image analysis of colocalization of nuclear DNA and GFP labelled HIF-1α in stable transformants.

HIF-1α is regarded as a target for drug development in several diseases such as cancer. For high throughput screening of HIF-1α-targeted drug, we need to examine the activity quantitatively. In the present study, we proposed a method where stable expression system of HIF-1α was combined with image correlation analysis.

Comparison of mRNA expression of transcriptional factors and intercalated disk constituent proteins between in vivo and cultured cardiomyocytes.

The weak contractile force exerted by engineered cardiac muscle is a big problem in cardiac muscle tissue engineering, even though the field has made great progress over the past decade. We believe that one major reason for the weak contractile force is that the expression of genes regulating cardiomyocyte differentiation and cardiac tissue syncytium may be different for in vivo and cultured cells. In the present study, we investigated the difference of mRNA expression under in vivo and culture conditions in order to seek a target for further gene transfer treatment in the process of cardiac tissue construction.

Direct quantification of gene expression using fluorescence correlation spectroscopy.

Among the methods for single molecule detection in the field of medicinal chemistry, the importance of fluorescence correlation spectroscopy (FCS) is growing. FCS has the advantage of permitting us to determine the number of fluorescent molecules and the diffusion constant dependent on the molecular weight without any physical separation process such as gel electrophoresis. Thus this method is appropriate for studies on the hybridization of fluorescence-labeled oligonucleotides with RNA or DNA as well as gene expression through translation of a target protein linked with green fluorescent protein.

Construction of fibroblast-collagen gels with orientated fibrils induced by static or dynamic stress: toward the fabrication of small tendon grafts.

As a step toward the fabrication of small tendon grafts, fibroblast-collagen gels were constructed with orientated fibrils induced by static or dynamic loading. Three groups of gel samples, each consisting of 1.0 x 10(6) fibroblasts and 2 mg type I collagen, were fabricated: freely contracted gels formed the control group; contraction-directed gels made up the static group (the gel contraction was directed perpendicular to an axis made by two anchors buried in the gels so that the constraint stress exerted by the two anchors was imposed on the gel); and for the dynamic group, a specific loading pattern (free contraction followed by cyclic stretching using a tensile bioreactor) was employed.

Constraint stress, microstructural characteristics, and enhanced mechanical properties of a special fibroblast-embedded collagen construct.

Cell-contracted collagen gels could provide rejection-free biomaterials for tissue engineering, but their application is limited by relatively low mechanical strength. We developed a special type I collagen construct (based on embedded fibroblasts) that was formed into a gel thread by using two anchors to constrain gel contraction in one direction. Each gel thread contained 2 mg of type I collagen and 1.

In vivo oxygen imaging using green fluorescent protein.

In vivo oxygen measurement is the key to understanding how biological systems dynamically adapt to reductions in oxygen supply. High spatial resolution oxygen imaging is of particular importance because recent studies address the significance of within-tissue and within-cell heterogeneities in oxygen concentration in health and disease. Here, we report a new technique for in vivo molecular imaging of oxygen in organs using green fluorescent protein (GFP).

Genetic oxygen sensor: GFP as an indicator of intracellular oxygenation.

We report in this article a new method for in vivo oxygen measurement using green fluorescence protein (GFP). COS7 cells were transiently transfected with an expression vector, pCMX-GFP, using a polyethylenimine reagent and cultured for 48 hrs. After exposure of the cell to anoxic gas (O2 < .

Detection of oxidative stress-induced mitochondrial DNA damage using fluorescence correlation spectroscopy.

Using fluorescence correlation spectroscopy (FCS), we tested the feasibility of rapid detection of oxidative damage of mitochondrial DNA (mtDNA) in a small volume. The complete mtDNA genome was amplified by long polymerase chain reaction (LPCR), and the product was fluorescently labeled with an intercalating dye, YOYO-1. The fluorescence autocorrelation function was analyzed using a simple two-component model with the diffusion time of 0.

Quantification of size distribution of restriction fragments in mitochondrial genome using fluorescence correlation spectroscopy.

A crucial investigation is to quantify restriction fragment length polymorphisms without gel electrophoresis, as the distribution of fragment size is mainly evaluated on the gel, which cannot be easily quantified. We developed a method to determine the fragmentation of the mitochondrial genome caused by restriction enzymes using fluorescence correlation spectroscopy (FCS). Distribution of fragment size was evaluated by the decrease in amplitude of the fluorescence correlation function while the mitochondrial genome PCR product was digested with Hga I or Hae III.

Effect of cobalt on the liver glycogen content in the streptozotocin-induced diabetic rats.

Cobalt decreases blood glucose in diabetic rats but the mechanisms involved are unclear. To determine the contribution of glycogen metabolism to glycemia-lowering effect, glycogen contents of liver and muscle in the streptozotocin-induced diabetic rats were determined. The liver glycogen was depleted in diabetic rats.

Relationship between the gene expression of c-fos and degree of hypoxia in rat brain, as revealed by near-infrared spectroscopy.

Hypoxic induction of c-fos was studied in rat brains as a function of the cerebral oxygenation state using near-infrared spectroscopy by which the hemoglobin oxygenation state and redox state of mitochondrial cytochrome oxidase can be monitored noninvasively. Following reoxygenation after hypoxia, the expression of c-fos and MAP2 mRNAs was determined by reverse transcription-coupled PCR. The expression of MAP2 remained unchanged throughout all conditions from 21 to 8% FiO2.