Glycine nitrosation and signature mutations in the p53 tumour suppressor gene: a molecular link between diet and cancers of the gastro-intestinal tract.

Genotoxic agents derived from diet may contribute to the total human burden of potentially carcinogenic DNA damage. For example, glycine is a simple primary amino acid and a commonly found dietary constituent in the red meat. The nitrosation of glycine would probably constitute a major source of alkylating agents, as glycine is one of the most abundant amino acids found in nature. It has been shown that O6- carboxymethyl-2'-deoxyguanosine, the major 06-guanine adduct of nitrosated glycine derivatives, is not repaired by 06-alkylguanine-DNA-alkyltransferase so could accumulate in the DNA of GI tract tissues as a promutagenic lesion. In DNA extracted from human gastric biopsies and white blood cells, using a sensitive Immunoblot assay, 06-CMdG adduct has been detected suggesting that the formation of carboxymethylating agents, possibly via nitrosation of glycine, does occur in man. Therefore genotoxic properties of the 06-carboxymethyl-2'-deoxyguanosine adduct were studied. 06-carboxymethyl-2'-deoxyguanosine adduct has been successfully synthesised and incorporated site specifically in to oligonucleotides. Nucleoside composition analysis of site specifically modified sequences confirmed the presence of O6- carboxymethylguanine adduct. The melting curves studies showed qualitative differences between base pair stabilities formed by 06-CMdG adduct with respect to 06-MedG adduct and normal 2’-dG. 06-CMdG:T base pair was stable than O6- CMdG:C base pair suggesting that 06-CMdG adduct like 06-MedG might preferentially base pair with thymidine. However, quantitative studies on the melting temperatures of 06-CMdG adduct were not fully conclusive. Clearly further effort and experimentation is needed to substantiate the qualitative data. The mutagenic potential of 06-carboxymethyl-2'-guanosine adduct was studied using Amplification Refractory Mutation System (ARMS) PCR technique. A shuttle vector was constructed by incorporating a single 06-CMdG adduct site specifically in to p53 cDNA of plasmid, pLS76. The mutagenesis studies have indicated that O6- carboxymethyl-2'-deoxyguanosine adduct can induce both GC—>AT transition mutations and GC—>TA transversion mutations. Further studies are needed to focus on mutation specificity and frequency of 06-CMdG adduct. The mutagenesis studies on potassium diazoacetate, model compound of nitrosoglycine derivatives did not induce any functional mutations in the p53gene of embryonic fibroblast cells of Human p53 knock in (HUPKI) mouse. However, this is mainly due to problems associated with KDA stability rather than the toxicity of the compound. The results presented in this thesis highlight some key aspects of methodology as well as the significance of mutagenecity of 06-CMdG adduct with respect to diet-related cancer risk

L&D Manual Turn Lane Storage Validation/Update

Queuing occurs at intersections mostly due to overflow or inadequacy of turn bays. The ODOT L&D Manual Volume 1 has storage requirements for both signalized and unsignalized intersections. Figures 401-9E and 401-10E of the L&D Manual provide the required turn lane storage lengths which should be compared with the real world conditions to check for adequacy of these lengths as a measure of ensuring that accesses to the left turn lanes are not blocked. In addition to the projected turn lane volume, ODOT’s methodology incorporates both deceleration (based on the speed of the roadway) and potential blockage from the adjacent through lane. Currently, however, there are no records whether these storage lengths computed by the methodology put forth in this manual are valid and accurately represent the actual conditions at intersections in Ohio. This study used real world traffic and queue storage data at some intersections and analyzed these data to validate the model ODOT is currently using. This study used the observed field data to evaluate the ODOT’s model of storage length at intersections. In addition, the queue storage lengths observed from field data were compared with the prediction results of HCS and SYNCHRO computer packages. The model evaluation task evaluated the level of precision of each of the three models (ODOT, HCS, and SYNCHRO) with respect to the field data observation. L&D Manual lead the way by accurately predicting the observed queues by about 81.6% and closely followed by HCS, which also had a 79.2% prediction accuracy. SYNCHRO was by far the lowest with a 46.0% prediction accuracy

L&D Manual Turn Lane Storage Validation/Update

Queuing occurs at intersections mostly due to overflow or inadequacy of turn bays. The ODOT L&D Manual Volume 1 has storage requirements for both signalized and unsignalized intersections. Figures 401-9E and 401-10E of the L&D Manual provide the required turn lane storage lengths which should be compared with the real world conditions to check for adequacy of these lengths as a measure of ensuring that accesses to the left turn lanes are not blocked. In addition to the projected turn lane volume, ODOT’s methodology incorporates both deceleration (based on the speed of the roadway) and potential blockage from the adjacent through lane. Currently, however, there are no records whether these storage lengths computed by the methodology put forth in this manual are valid and accurately represent the actual conditions at intersections in Ohio. This study used real world traffic and queue storage data at some intersections and analyzed these data to validate the model ODOT is currently using. This study used the observed field data to evaluate the ODOT’s model of storage length at intersections. In addition, the queue storage lengths observed from field data were compared with the prediction results of HCS and SYNCHRO computer packages. The model evaluation task evaluated the level of precision of each of the three models (ODOT, HCS, and SYNCHRO) with respect to the field data observation. L&D Manual lead the way by accurately predicting the observed queues by about 81.6% and closely followed by HCS, which also had a 79.2% prediction accuracy. SYNCHRO was by far the lowest with a 46.0% prediction accuracy

Computerized Optimum Dimensioning of Prestressed Homogenous Steel I-Beam

The economy of a prestressed steel beam can be realized only when relevant parameters of optimum magnitude are chosen. The present work aims at finding out the optimum dimensions of a simply supported, laterally unsupported, prestressed steel I-beam for a given span and load carrying capacity. Iterative calculations involved in analysis were performed with the help of a ‘C’ program developed by the authors in Turbo ‘C’ Environment. It was observed that the ratio of top fiber stress at working loads to the permissible stress is more than 0.9 for all the span lengths for the finalized cross-sections. This means that the cross-section is being effectively utilized. Deflection increases slowly for an increase in the load carrying capacity beyond 16kN/m. This means that pre-stressed steel beams are ideal for structures subjected to total load greater than 16kN/m. For a given load carrying capacity and span, e/D ratio has to be in between 0.45 to 0.7 for optimum utilization of the available cross section.The economy of a prestressed steel beam can be realized only when relevant parameters of optimum magnitude are chosen. The present work aims at finding out the optimum dimensions of a simply supported, laterally unsupported, prestressed steel I-beam for a given span and load carrying capacity. The span of the beam was limited to 12 m while the load carrying capacity was limited to 100 kN/m for this study. A straight tendon configuration over the whole span is considered and the losses occurring in the tendon are neglected. The safety of various sets of dimensions ranging from the minimum dimensions of I-section in IS-Hand Book-1 to their maximum dimensions for different pre-stressing forces and eccentricities are checked. The set with minimum cross sectional area is chosen. Iterative calculations involved in analysis were performed with the help of a ‘C’ program developed by the authors in Turbo ‘C’ Environment. It was observed that the ratio of top fiber stress at working loads to the permissible stress is more than 0.9 for all the spans for the finalized cross-sections. This means that the cross-section is being effectively utilized. For a given load carrying capacity and span, eccentricity to depth ratio has to be in between 0.45 to 0.7 for optimum utilization of the available cross section. It is also observed that the maximum pre-stressing force equal to 0.25 times the permissible bending compressive stress can be applied

Proton magnetic resonance spectroscopy in multiple sclerosis.

Proton magnetic resonance spectroscopy ((1)H-MRS) provides tissue metabolic information in vivo. This article reviews the role of MRS-determined metabolic alterations in lesions, normal-appearing white matter, gray matter, and spinal cord in advancing our knowledge of pathologic changes in multiple sclerosis (MS). In addition, the role of MRS in objectively evaluating therapeutic efficacy is reviewed. This potential metabolic information makes MRS a unique tool to follow MS disease evolution, understand its pathogenesis, evaluate the disease severity, establish a prognosis, and objectively evaluate the efficacy of therapeutic interventions

A preliminary longitudinal study of white matter alteration in cocaine use disorder subjects

Background Previous diffusion tensor imaging (DTI) studies have consistently shown that subjects with cocaine use disorder (CocUD) had altered white matter microstructure in the corpus callosum. It is believed that these alterations are due to preexisting factors, chronic cocaine use, or both. However, there is no published longitudinal DTI study on human cocaine users yet which could shed light on the relationship between cocaine use and DTI findings. Methods This study used a longitudinal design and DTI to test if the white matter microstructure shows quicker alteration in CocUD subjects than controls. DTI data were acquired from eleven CocUD subjects who participated a treatment study and eleven non-drug-using controls at baseline (Scan 1) and after ten weeks (Scan 2). The baseline fractional anisotropy (FA), a general measure of white matter microstucture, and the change in FA (ΔFA, equals Scan 1 FA minus Scan 2 FA) were both compared between groups. Results The two groups did not show a difference in FA at baseline. The CocUD subjects had significantly greater ΔFA than the controls in the left splenium of the corpus callosum. In CocUD subjects, greater ΔFA in this region was associated with shorter lifetime cocaine use and greater number of positive cocaine urine samples collected during the treatment. Conclusion The finding in the left splenium is consistent with previous animal studies and provide indirect evidence about the effects of chronic cocaine use on white matter alterations. The subject sample size is small, therefore the results should be treated as preliminary

Symmetric inverse consistent nonlinear registration driven by mutual information.

A nonlinear viscoelastic image registration algorithm based on the demons paradigm and incorporating inverse consistent constraint (ICC) is implemented. An inverse consistent and symmetric cost function using mutual information (MI) as a similarity measure is employed. The cost function also includes regularization of transformation and inverse consistent error (ICE). The uncertainties in balancing various terms in the cost function are avoided by alternatively minimizing the similarity measure, the regularization of the transformation, and the ICE terms. The diffeomorphism of registration for preventing folding and/or tearing in the deformation is achieved by the composition scheme. The quality of image registration is first demonstrated by constructing brain atlas from 20 adult brains (age range 30-60). It is shown that with this registration technique: (1) the Jacobian determinant is positive for all voxels and (2) the average ICE is around 0.004 voxels with a maximum value below 0.1 voxels. Further, the deformation-based segmentation on Internet Brain Segmentation Repository, a publicly available dataset, has yielded high Dice similarity index (DSI) of 94.7% for the cerebellum and 74.7% for the hippocampus, attesting to the quality of our registration method

Generalized fuzzy clustering for segmentation of multi-spectral magnetic resonance images.

An integrated approach for multi-spectral segmentation of MR images is presented. This method is based on the fuzzy c-means (FCM) and includes bias field correction and contextual constraints over spatial intensity distribution and accounts for the non-spherical cluster\u27s shape in the feature space. The bias field is modeled as a linear combination of smooth polynomial basis functions for fast computation in the clustering iterations. Regularization terms for the neighborhood continuity of intensity are added into the FCM cost functions. To reduce the computational complexity, the contextual regularizations are separated from the clustering iterations. Since the feature space is not isotropic, distance measure adopted in Gustafson-Kessel (G-K) algorithm is used instead of the Euclidean distance, to account for the non-spherical shape of the clusters in the feature space. These algorithms are quantitatively evaluated on MR brain images using the similarity measures

Brain fiber tract plasticity in experimental spinal cord injury: diffusion tensor imaging.

Diffusion tensor imaging (DTI) and immunohistochemistry were performed in spinal cord injured rats to understand the basis for activation of multiple regions in the brain observed in functional magnetic resonance imaging (fMRI) studies. The measured fractional anisotropy (FA), a scalar measure of diffusion anisotropy, along the region encompassing corticospinal tracts (CST) indicates significant differences between control and injured groups in the 3 to 4 mm area posterior to bregma that correspond to internal capsule and cerebral peduncle. Additionally, DTI-based tractography in injured animals showed increased number of fibers that extend towards the cortex terminating in the regions that were activated in fMRI. Both the internal capsule and cerebral peduncle demonstrated an increase in GFAP-immunoreactivity compared to control animals. GAP-43 expression also indicates plasticity in the internal capsule. These studies suggest that the previously observed multiple regions of activation in spinal cord injury are, at least in part, due to the formation of new fibers