Travis Clark

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Animal studies suggest that chronic cocaine exposure may increase the function and/or synthesis of the dopamine transporter (DAT) under certain conditions, but the literature is complex. In order to test the hypothesis that cocaine exposure alters the DAT in humans, preliminary studies were done characterizing [3H]WIN 35428 binding in human striatum from(More)
OBJECTIVE This study tested the hypothesis that cocaine depletes dopamine levels in the brain. METHOD Levels of dopamine, serotonin, and their metabolites in the frontal cortex and striatum of nine cocaine users and nine matched control subjects who had never used cocaine were determined from postmortem autopsy material. RESULTS The cocaine users had(More)
Beta-adrenergic binding in frontal cortex samples from suicide victims has been reported to be increased, unaltered, and decreased compared to matched controls. Subject's diagnoses and drug exposures in these studies were not equivalently documented and were possibly different. In the present study, diagnostic and symptomatic information was systematically(More)
Amino acids have markedly different taste properties depending upon their chirality and the structure of their side chains. They can modify the taste quality of foods in which they are found naturally or to which they are added depending on their concentrations. In this study, the influence of chirality of amino acids on the growth in perceived taste(More)
Advances in next-generation sequencing (NGS) technologies have greatly improved our ability to detect genomic variants for biomedical research. In particular, NGS technologies have been recently applied with great success to the discovery of mutations associated with the growth of various tumours and in rare Mendelian diseases. The advance in NGS(More)
Seventeen sweeteners varying widely in chemical structure were arranged in a three-dimensional space by two multidimensional scaling procedures, INDSCAL and ALSCAL. Fructose, glucose, sorbose, xylitol and xylose tended to fall near one another. Two sweeteners with a syrupy component, maltose and sorbitol, fell further away. Ca cyclamate and the dipeptide(More)
MicroRNAseq (miRNAseq) is a form of RNAseq technology that has become an increasingly popular alternative to miRNA expression profiling. Unlike messenger RNA (mRNA), miRNA extraction can be difficult, and sequencing such small RNA can also be problematic. We designed a study to test the reproducibility of miRNAseq technology and the performance of the two(More)
Taste detection thresholds for 11 sweeteners varying widely in chemical structure were determined for young and elderly subjects. The rank orders of the thresholds for young and elderly were highly correlated (Spearman's rho=0.976) although the thresholds were 2.72 times higher on the average for the elderly when compared with the young. This decreased(More)
Serial dilutions of twenty-three amino acids were presented to young and elderly subjects who rated the relative intensities of the dilutions using the magnitude estimation procedure. In each case the slope of the psychophysical function relating concentration and perceived intensity was flatter for the elderly subjects: the mean ratio (slope (young)/slope(More)
We report detailed photophysical studies on the two-photon fluorescence processes of the solvatochromic fluorophore 4-DMN as a conjugate of the calmodulin (CaM) and the associated CaM-binding peptide M13. Strong two-photon fluorescence enhancement has been observed which is associated with calcium binding. It is found that the two-photon absorption(More)