Mammalian Stem Cells Reprogramming in Response to Terahertz Radiation

We report that extended exposure to broad-spectrum terahertz radiation results in specific changes in cellular functions that are closely related to DNA-directed gene transcription. Our gene chip survey of gene expression shows that whereas 89% of the protein coding genes in mouse stem cells do not respond to the applied terahertz radiation, certain genes are activated, while other are repressed. RT-PCR experiments with selected gene probes corresponding to transcripts in the three groups of genes detail the gene specific effect. The response was not only gene specific but also irradiation conditions dependent. Our findings suggest that the applied terahertz irradiation accelerates cell differentiation toward adipose phenotype by activating the transcription factor peroxisome proliferator-activated receptor gamma (PPARG). Finally, our molecular dynamics computer simulations indicate that the local breathing dynamics of the PPARG promoter DNA coincides with the gene specific response to the THz radiation. We propose that THz radiation is a potential tool for cellular reprogramming

Assessment of Epidermal Growth Factor Receptor (EGFR) expression in human meningioma

<p>Abstract</p> <p>Purpose</p> <p>This study explores whether meningioma expresses epidermal growth factor receptor (EGFR) and determines if there is a correlation between the WHO grade of this tumor and the degree of EGFR expression.</p> <p>Methods</p> <p>Following institutional review board approval, 113 meningioma specimens from 89 patients were chosen. Of these, 85 were used for final analysis. After a blinded review, immunohistochemical stains for EGFR were performed. Staining intensity (SI) was scored on a scale 0-3 (from no staining to strong staining). Staining percentage of immunoreactive cells (SP) was scored 1-5 (from the least to the maximum percent of the specimen staining). Immunohistochemical score (IHS) was calculated as the product of SI and SP.</p> <p>Results</p> <p>Eighty-five samples of meningioma were classified in accordance with World Health Organization (WHO) criteria: benign 57/85 (67%), atypical 23/85 (27%), and malignant 5/85 (6%). The majority of samples demonstrated a moderate SI for EGFR. IHS for EGFR demonstrated a significant association between SI and histopathologic subtype. Also, there was a correlation between the SP and histopathologic subtype (p = 0.029). A significant association was determined when the benign and the atypical samples were compared to the malignant with respect to the SP (p = 0.009). While there was a range of the IHS for the benign and the atypical histologic subtypes, malignant tumors exhibited the lowest score and were statistically different from the benign and the atypical specimens (p < 0.001).</p> <p>Conclusions</p> <p>To our knowledge, this represents the largest series of meningioma samples analyzed for EGFR expression reported in the literature. EGFR expression is greatest in benign meningiomas and may serve a potential target for therapeutic intervention with selective EGFR inhibitors.</p

Isolation and characterization of germ line DNA from mouse sperm.

Mouse germ line DNA was isolated from sperm by a physicochemical procedure that preferentially destroys contaminating somatic cell DNA. The use of reducing conditions and chelating agents in combination with phenol permitted extraction of molecular weight DNA from mature sperm nuclei with approximately 80% efficiency. Less than 0.1% somatic cell DNA contamination remained in sperm DNA prepared by this method. Germ line DNA was characterized by determination of its ultraviolet absorbance spectrum, buoyant density in cesium chloride, and melting profile on a hydroxyapatite column. Contamination by mitochondrial DNA was assessed by cesium chloride/ethidium bromide gradient centrifugation. The significance of the mouse germ line DNA isolation procedure is discussed with respect to the possible genetic transmission of mammary tumor virus and leukemia virus, the origin of antibody diversity, and the origin of testicular teratomas

Image-based computational hemodynamics of distal aortic arch recoarctation following the Norwood procedure

Currently, few applications of computational hemodynamics predict outcomes after palliative surgery for congenital heart defects such as hypolastic left heart syndrome in infants. Here, we report on three-dimensional imaging methods for modeling recoarctation that commonly occurs in the distal aortic arch following the Norwood procedure. We used computer-aided design to simulate seven stages of increasing stenosis, analyze the resulting hemodynamics, and visualize the impairment of blood flow. A disproportionate drop in pressure occurred when stenosis reached 20% of the cross-sectional area of the descending aorta. The corresponding decrease in blood flow in the descending aorta was relatively small, however. Accordingly our findings suggest a reasonable approach to this phenomenon is watchful waiting rather than immediate surgical intervention. Such patient-specific predictions appear to be valuable for minimizing the risks of corrective surgery. These methods also may be applied to procedures for all eviating other congenital heart defects.6 page(s

An Approach of Computational Hemodynamics for Cardiovascular Flow Simulation

Computational fluid dynamics (CFD) is one of available methods to quantitatively evaluate the treatments of cardiovascular disease. However, currently, applications of this technology to cardiac surgery are few due to the complexity of performing physiological simulation. Here, we used CFD to study the outcome of the Norwood surgical procedure for palliating hypoplastic left heart syndrome in a 33-month-old child. The Reynolds number for post-surgical flow calculated at the peak of systole was about 4000, consistent with turbulent flow. During diastole, by contrast, the flow reduced to low speed, suggesting the strong transition flow from systole to diastole. Therefore, to improve the simulation of transitional flow, we determined that time step intervals of 10-5 second were best in using the k - e turbulence model. We also develop a new boundary condition to simulate blood pressure wave reflection from peripheral vessels in order to physiologically capture pressure recovery and correctly obtained flow through each arch-branch and flow pattern in the coronary. Then we computed time-varying energy losses, local pressure, and wall shear stress at the anastomosis to evaluate the surgical outcome. The results suggest the time step and boundary conditions that take account of pressure wave reflection improve simulation of cardiovascular flow.8 page(s