Medical Biotechnology Commons^™

Extraction Of Intrinsic Fluorescence From Single Fiber Fluorescence Measurements On A Turbid Medium: Experimental Validation, U. A. Gamm, C. L. Hoy, F. Van Leeuwen - Van Zaane, H. J. C. M. Sterenborg, S. C. Kanick, D J. Robinson, A. Amelink

Dartmouth Scholarship

Abstract

The detailed mechanisms associated with the influence of scattering and absorption properties on the fluorescence intensity sampled by a single optical fiber have recently been elucidated based on Monte Carlo simulated data. Here we develop an experimental single fiber fluorescence (SFF) spectroscopy setup and validate the Monte Carlo data and semi-empirical model equation that describes the SFF signal as a function of scattering. We present a calibration procedure that corrects the SFF signal for all system-related, wavelength dependent transmission efficiencies to yield an absolute value of intrinsic fluorescence. The validity of the Monte Carlo data and semi-empirical model is …

Advances In Optics For Biotechnology, Medicine And Surgery, Maryann Fitzmaurice, Brian W. Pogue, Guillermo J. Tearney, James W. Tunnell

Dartmouth Scholarship

The guest editors introduce a Biomedical Optics Express feature issue that includes contributions from participants at the 2013 conference on Advances in Optics for Biotechnology, Medicine and Surgery XIII.

Measurement Of The Oxidation State Of Mitochondrial Cytochrome C From The Neocortex Of The Mammalian Brain, Y. Sakata, M. Abajian, M. O. Ripple, R. Springett

Dartmouth Scholarship

Diffuse optical remission spectra from the mammalian neocortex at visible wavelengths contain spectral features originating from the mitochondria. A new algorithm is presented, based on analytically relating the first differential of the attenuation spectrum to the first differential of the chromophore spectra, that can separate and calculate the oxidation state of cytochrome c as well as the absolute concentration and saturation of hemoglobin. The algorithm is validated in phantoms and then tested on the neocortex of the rat during an anoxic challenge. Implementation of the algorithm will provide detailed information of mitochondrial oxygenation and mitochondrial function in physiological studies of …

A Coupled Finite Element-Boundary Element Method For Modeling Diffusion Equation In 3d Multi-Modality Optical Imaging, Subhadra Srinivasan, Hamid R. Ghadyani, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

Three dimensional image reconstruction for multi-modality optical spectroscopy systems needs computationally efficient forward solvers with minimum meshing complexity, while allowing the flexibility to apply spatial constraints. Existing models based on the finite element method (FEM) require full 3D volume meshing to incorporate constraints related to anatomical structure via techniques such as regularization. Alternate approaches such as the boundary element method (BEM) require only surface discretization but assume homogeneous or piece-wise constant domains that can be limiting. Here, a coupled finite element-boundary element method (coupled FE-BEM) approach is demonstrated for modeling light diffusion in 3D, which uses surfaces to model exterior …

Heme Deficiency In Alzheimer's Disease: A Possible Connection To Porphyria, Barney E. Dwyer, Meghan L. Stone, Xiongwei Zhu, George Perry, Mark A. Smith

Dartmouth Scholarship

Mechanisms that cause Alzheimer's disease (AD), an invariably fatal neurodegenerative disease, are unknown. Important recent data indicate that neuronal heme deficiency may contribute to AD pathogenesis. If true, factors that contribute to the intracellular heme deficiency could potentially alter the course of AD. The porphyrias are metabolic disorders characterized by enzyme deficiencies in the heme biosynthetic pathway. We hypothesize that AD may differ significantly in individuals possessing the genetic trait for an acute hepatic porphyria. We elaborate on this hypothesis and briefly review the characteristics of the acute hepatic porphyrias that may be relevant to AD. We note the proximity …

Interpreting Patterns Of Gene Expression With Self-Organizing Maps: Methods And Application To Hematopoietic Differentiation, Pablo Tamayo, Donna Slonim, Jill Mesirov, Qing Zhu, Sutisak Kitareewan, Ethan Dmitrovsky

Dartmouth Scholarship

Array technologies have made it straightforward to monitor simultaneously the expression pattern of thousands of genes. The challenge now is to interpret such massive data sets. The first step is to extract the fundamental patterns of gene expression inherent in the data. This paper describes the application of self-organizing maps, a type of mathematical cluster analysis that is particularly well suited for recognizing and classifying features in complex, multidimensional data. The method has been implemented in a publicly available computer package, GENECLUSTER, that performs the analytical calculations and provides easy data visualization. To illustrate the value of such analysis, the …