White Counselor Trainees\u27 Racial Identity and Working Alliance Perceptions

Racial identity has been theorized to significantly affect cross-racial counseling relationships (Helms, 1984, 1995). This study examined the direct impact of White racial identity of 124 counselor trainees on working alliance formation in a same-racial and cross-racial vicarious counseling analogue. Regardless of the race of the client, disintegration and reintegration attitudes negatively affected working alliance ratings, and pseudoindependent and autonomy attitudes positively affected working alliance ratings. Implications for counseling, supervision, training, and research are discussed

White Counselor Trainees\u27 Racial Identity and Working Alliance Perceptions

Racial identity has been theorized to significantly affect cross-racial counseling relationships (Helms, 1984, 1995). This study examined the direct impact of White racial identity of 124 counselor trainees on working alliance formation in a same-racial and cross-racial vicarious counseling analogue. Regardless of the race of the client, disintegration and reintegration attitudes negatively affected working alliance ratings, and pseudoindependent and autonomy attitudes positively affected working alliance ratings. Implications for counseling, supervision, training, and research are discussed

Investigating the pathogenesis of mitochondrial dysfunction in mitochondrial and other myopathies

PhD ThesisSkeletal muscle contains a large number of mitochondria, known for their production of ATP via oxidative phosphorylation, which is of vital importance for energy-demanding muscle contraction. However, the mitochondria also have a plethora of other functions such as; calcium ion homeostasis, iron-sulphur cluster formation, redox signalling and apoptotic signalling, which are of similarly high importance to skeletal muscle function. As such, it is of little surprise that mitochondrial dysfunction has been linked to a large number of neuromuscular conditions as well as healthy skeletal muscle ageing and sarcopenia. However, the mechanisms by which the dysfunction occurs and its pathological and clinical relevance remains to be understood. This thesis therefore aims to advance the understanding of mechanisms and pathological significance of mitochondrial dysfunction in mitochondrial disease, myofibrillar myopathy, dysferlin myopathy and skeletal muscle ageing. The project was approached from three very different angles. Firstly, by exploring mitochondrial dysfunction in myofibrillar myopathy, dysferlinopathy and looking for potential links to disease pathology. Secondly, by attempting to understand mechanisms and factors effecting clonal expansion of mitochondrial DNA (mtDNA) mutations, which accumulate with age in post mitotic tissues in both healthy individuals and those affected by neuromuscular and neurodegenerative disorders. Both of these approaches were investigated using histochemical, immunocytochemical and single cell genetic methodologies. Finally, possible links between mitochondrial morphology, ultrastructure and function were investigated using electron microscopy techniques. This work provides novel insights into mitochondrial involvement in neuromuscular disease pathology. Key findings include; the reduction of mitochondrial mass in myofibrillar myopathy, increased respiratory chain deficiency in some patients with dysferlinopathy, the spectrum of mitochondrial ultrastructural defects in mitochondrial myopathy, the anisotropic nature of the skeletal muscle mitochondria, the perinuclear origins of mtDNA deletions and their clonal expansion due to retrograde signalling and mitochondrial biogenesis.MRC supplementary award committee at Newcastle University for granting me additional funding to undertake a period of work at Columbia Universit

Investigation of genetic susceptibility to the porcine reproductive and respiratory syndrome virus between commercial breeding stock lines of pigs

The objectives in the studies described herein were to evaluate the use of an antemortem in vitro test as an indicator in identifying commercial breeding stock lines with high and low susceptibility to PRRSV and to evaluate the pigs from lines selected from the first objective in an experimental infection model. Macrophages have been shown to be the cell type PRRSV preferentially infects and subsequently manipulates to achieve efficient replication and production of progeny virions. The in vitro assay was therefore designed to evaluate the percentage of macrophages derived from peripheral blood monocytes that are susceptible to infection in culture by PRRSV. In order to address objective one, six genetically diverse lines of pigs maintained as commercial breeding seed-stock were evaluated for differences in their in vitro susceptibility to PRRSV. The specific aim of objective one was to determine if the in vitro PRRSV flow cytometric assay could be utilized to detect the existence of genetic variability in the susceptibility of the host to PRRSV infection. From the results of the six screened lines, two genetically distinct lines with opposing in vitro results were selected for further study to confirm the results of the antemortem in vitro assay screening;The second objective was to infect pigs from lines demonstrated to have high and low susceptibility in the in vitro assay in order to evaluate variation of disease traits in vivo. The average percentage of PRRSV-infected macrophages in culture was shown to differ statistically between the two chosen lines, indicating that the susceptibility of macrophages in culture varied. To investigate these differences in vivo, PRRSV challenge studies were conducted in four independent replicates. Pigs were experimentally infected and evaluated for disease susceptibility using the flow cytometric assay, clinical presentation of respiratory disease, macroscopic lesions, microscopic lesions, and virus titers. The overall aim of the investigations reported here were to provide evidence for a genetic basis to susceptibility to PRRSV-induced infection and disease utilizing both an in vitro PRRSV susceptibility assay and experimental challenge and to evaluate the usefulness of the in vitro flow cytometric assay in predicting susceptibility upon challenge

Attenuation correction for TOF-PET with a limited number of stationary coincidence line-sources

INTRODUCTION Accurate attenuation correction remains a major issue in combined PET/MRI. We have previously presented a method to derive the attenuation map by performing a transmission scan using an annulus-shaped source placed close to the edge of the FOV of the scanner. With this method, simultaneous transmission and emission data acquisition is possible as transmission data can be extracted using Time-of-Flight (TOF) information. As this method is strongly influenced by photon scatter and dead time effects, its performance depends on the accuracy of the correction techniques for these effects. In this work we present a new approach in which the annulus source is replaced with a limited number of line-sources positioned at 35 cm from the center of the FOV. By including the location of the line sources into the algorithm, the extraction of true transmission data can be improved. The setup was validated with simulations studies and evaluated with a phantom study acquired on the LaBr3-based TOF-PET scanner installed at UPENN. MATERIALS AND METHODS First we performed GATE simulations using the digital NCAT phantom. The phantom was segmented into bone, lung and soft-tissue and injected with 6.5 Mbq/kg 18F-FDG. Simultaneous transmission/emission scans of 3 minutes were simulated using 6, 12 and 24 18F-FDG line sources with a total activity of 0.5 mCi. To obtain the attenuation map, the transmission data is first extracted using TOF information. To reduce misclassification of prompt emission data as transmission data, only events on LORs, which pass within a radial distance of 1 cm from at least one line source, are accepted. The attenuation map is then reconstructed using an iterative gradient descent approach. As a proof of concept, the method was evaluated on the LaBr3-based TOF PET scanner using an anthropomorphic torso phantom injected with 2mCi of 18F-FDG. 24 line-sources of 20μCi each were fixed to a wooden template at the back of the scanner. Simultaneous transmission/emission scans were acquired using 24 line sources. RESULTS Simulation results demonstrate that the fraction of scattered emission events classified as transmission data was reduced from 4.32% with the annulus source to 2.29%, 1.25% and 0.63% for the 24, 12 and 6 line sources respectively. The fraction of misclassified true emission events was reduced from 1.10% to 0.42%, 0.24% and 0.13% respectively. Only in case of 6 line sources, the attenuation maps showed severe artifacts. Compared to the classification solely based on TOF-information, preliminary experimental results indicate an improvement in the accuracy of the attenuation coefficients of 10.44%, 0.12% and 5.09% for soft-tissue, lung and bone tissue respectively. CONCLUSION The proposed method can be used for attenuation correction in sequential or simultaneous TOF-PET/MRI systems. The PET transmission and emission data are acquired simultaneously so no acquisition time for attenuation correction is lost in PET or MRI. Attenuation maps with higher accuracy can be obtained by including information about the location of the line-sources. However, at least 12 line sources are needed to avoid severe artifacts

A Cation-π Interaction Discriminates among Sodium Channels That Are Either Sensitive or Resistant to Tetrodotoxin Block

Voltage-gated sodium channels control the upstroke of the action potential in excitable cells of nerve and muscle tissue, making them ideal targets for exogenous toxins that aim to squelch electrical excitability. One such toxin, tetrodotoxin (TTX), blocks sodium channels with nanomolar affinity only when an aromatic Phe or Tyr residue is present at a specific location in the external vestibule of the ion-conducting pore. To test whether TTX is attracted to Tyr401 of NaV1.4 through a cation-{pi} interaction, this aromatic residue was replaced with fluorinated derivatives of Phe using in vivo nonsense suppression. Consistent with a cation-{pi} interaction, increased fluorination of Phe401, which reduces the negative electrostatic potential on the aromatic face, caused a monotonic increase in the inhibitory constant for block. Trifluorination of the aromatic ring decreased TTX affinity by ~50-fold, a reduction similar to that caused by replacement with the comparably hydrophobic residue Leu. Furthermore, we show that an energetically equivalent cation-{pi} interaction underlies both use-dependent and tonic block by TTX. Our results are supported by high level ab initio quantum mechanical calculations applied to a model of TTX binding to benzene. Our analysis suggests that the aromatic side chain faces the permeation pathway where it orients TTX optimally and interacts with permeant ions. These results are the first of their kind to show the incorporation of unnatural amino acids into a voltage-gated sodium channel and demonstrate that a cation-{pi} interaction is responsible for the obligate nature of an aromatic at this position in TTX-sensitive sodium channels

Genome-Wide Prediction and Validation of Peptides That Bind Human Prosurvival Bcl-2 Proteins

Programmed cell death is regulated by interactions between pro-apoptotic and prosurvival members of the Bcl-2 family. Pro-apoptotic family members contain a weakly conserved BH3 motif that can adopt an alpha-helical structure and bind to a groove on prosurvival partners Bcl-x[subscript L], Bcl-w, Bcl-2, Mcl-1 and Bfl-1. Peptides corresponding to roughly 13 reported BH3 motifs have been verified to bind in this manner. Due to their short lengths and low sequence conservation, BH3 motifs are not detected using standard sequence-based bioinformatics approaches. Thus, it is possible that many additional proteins harbor BH3-like sequences that can mediate interactions with the Bcl-2 family. In this work, we used structure-based and data-based Bcl-2 interaction models to find new BH3-like peptides in the human proteome. We used peptide SPOT arrays to test candidate peptides for interaction with one or more of the prosurvival proteins Bcl-x[subscript L], Bcl-w, Bcl-2, Mcl-1 and Bfl-1. For the 36 most promising array candidates, we quantified binding to all five human receptors using direct and competition binding assays in solution. All 36 peptides showed evidence of interaction with at least one prosurvival protein, and 22 peptides bound at least one prosurvival protein with a dissociation constant between 1 and 500 nM; many peptides had specificity profiles not previously observed. We also screened the full-length parent proteins of a subset of array-tested peptides for binding to Bcl-x[subscript L] and Mcl-1. Finally, we used the peptide binding data, in conjunction with previously reported interactions, to assess the affinity and specificity prediction performance of different models.National Institutes of Health (U.S.) (Award GM084181)National Science Foundation (U.S.) (Grant 0821391)American Cancer Society (Postdoctoral Fellowship PF-12-155-01-DMC