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Your search keyword '"Krishnan, K. R. R."' showing total 39 results
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39 results on '"Krishnan, K. R. R."'

9. A functional alternative splicing mutation in human tryptophan hydroxylase-2

Author

Zhang, X, primary, Nicholls, P J, additional, Laje, G, additional, Sotnikova, T D, additional, Gainetdinov, R R, additional, Albert, P R, additional, Rajkowska, G, additional, Stockmeier, C A, additional, Speer, M C, additional, Steffens, D C, additional, Austin, M C, additional, McMahon, F J, additional, Krishnan, K R R, additional, Garcia-Blanco, M A, additional, and Caron, M G, additional

Published
2010
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18. Apolipoprotein E 4

Author

Krishnan, K. R. R., primary, Ritchie, J. C., additional, Tupler, L. A., additional, McDonald, W. M., additional, Knight, D., additional, Nemeroff, C. B., additional, and Marcovina, S., additional

Published
1994
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20. A functional alternative splicing mutation in human tryptophan hydroxylase-2.

Author

Zhang, X, Nicholls, P J, Laje, G, Sotnikova, T D, Gainetdinov, R R, Albert, P R, Rajkowska, G, Stockmeier, C A, Speer, M C, Steffens, D C, Austin, M C, McMahon, F J, Krishnan, K R R, Garcia-Blanco, M A, and Caron, M G

Subjects
CENTRAL nervous system diseases, SEROTONINERGIC mechanisms, GENETIC polymorphisms, HOMEOSTASIS, RNA splicing
Abstract

The brain serotonergic system has an essential role in the physiological functions of the central nervous system and dysregulation of serotonin (5-HT) homeostasis has been implicated in many neuropsychiatric disorders. The tryptophan hydroxylase-2 (TPH2) gene is the rate-limiting enzyme in brain 5-HT synthesis, and thus is an ideal candidate gene for understanding the role of dysregulation of brain serotonergic homeostasis. Here, we characterized a common, but functional single-nucleotide polymorphism (SNP rs1386493) in the TPH2 gene, which decreases efficiency of normal RNA splicing, resulting in a truncated TPH2 protein (TPH2-TR) by alternative splicing. TPH2-TR, which lacks TPH2 enzyme activity, dominant-negatively affects full-length TPH2 function, causing reduced 5-HT production. The predicted mRNA for TPH2-TR is present in postmortem brain of rs1386493 carriers. The rs13864923 variant does not appear to be overrepresented in either global or multiplex depression cohorts. However, in combination with other gene variants linked to 5-HT homeostasis, this variant may exhibit important epistatic influences. [ABSTRACT FROM AUTHOR]

Published
2011
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26. The COMT Val158Met polymorphism and cognition in depressed and nondepressed older adults.

Author

Potter, G. G., Taylor, W. D., McQuoid, D. R., Steffens, D. C., Welsh-Bohmer, K. A., and Krishnan, K. R. R.

Subjects
DEPRESSION in old age, COGNITION, METHYLTRANSFERASES, MENTAL depression, CLINICAL neuropsychology, PREFRONTAL cortex
Abstract

Objective The objective of the current study was to examine the relationship between the COMT Val158Met polymorphism and neuropsychological performance in depressed and nondepressed older adults. Methods One hundred and twenty-six clinically depressed older adults and 105 nondepressed comparison participants were compared on neuropsychological performance and COMT Val158Met (Val/Val, Val/Met, Met/Met). Results Based on multivariate regression models, the COMT Val158Met polymorphism was not associated with cognitive performance among depressed or nondepressed individuals, nor did this polymorphism account for the fact that depressed individuals performed worse than nondepressed individuals on several neuropsychological tests that are typically affected by depression. There was also no difference in frequency of the COMT Val158Met alleles between depressed and nondepressed individuals. Conclusions Although the current study found no association between COMT Val158Met polymorphism on a number of clinical neuropsychological tests that are typically found to be sensitive to depression, differential effects of the COMT Val158Met polymorphism on dopamine transmission in psychiatric and non-psychiatric populations may be further clarified by clinical research with neuroscience-based paradigms that segregate cognitive tasks into component processes with precise neural substrates, particularly with respect to the complex functions of the prefrontal cortex. Negative results can be important to narrowing down target processes and understanding the influence of clinical and demographic characteristics in studies of psychiatric genetics. [ABSTRACT FROM AUTHOR]

Published
2009
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27. Hippocampal sulcal cavities on MRI Relationship to age and apolipoprotein E genotype

Author

Barboriak, D. P., Doraiswamy, P. M., Krishnan, K. R. R., Vidyarthi, S., Sylvester, J., and Charles, H. C.

Abstract

Hippocampal sulcal cavities are usually considered incidental findings on brain MRI. In a group of 92 elderly volunteers, the authors graded the number and size of hippocampal sulcal cavities with brain MRI to obtain a cavity score. Cavity scores increased with age, and were higher in subjects carrying the APOE4 or 2 alleles than in subjects with the 3/3 genotype. Age-related morphologic changes in the hippocampus may be mediated by the APOEgenotype.

Published
2000

34. Tape Recording Auditory Hallucinations.

Author

Krishnan, K. R. R., Ellinwood Jr., E. H., and Goli, Veeraindar

Subjects
LETTERS to the editor, AUDITORY hallucinations
Abstract

A letter to the editor is presented in response to the article regarding auditory hallucinations published in the previous issue.

Published
1988
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39. Molecular imaging for depressive disorders.

Author

Lee TS, Quek SY, and Krishnan KR

Subjects
Humans, Brain metabolism, Depressive Disorder diagnostic imaging, Depressive Disorder metabolism, Magnetic Resonance Spectroscopy methods, Molecular Imaging methods, Positron-Emission Tomography methods
Abstract

Molecular imaging is the visualization, characterization, and measurement of biologic processes at the molecular and cellular levels in humans and other living systems. Molecular imaging techniques such as MR spectroscopy and PET have been used to explore the molecular pathophysiology of depression and assess treatment responses. MR spectroscopy is a noninvasive technique that assesses the levels of biochemical metabolites in the brain, while PET uses radioligands injected in the bloodstream that have high binding affinity for target molecules. MR spectroscopy findings suggest a role for glutamate/glutamine and gamma-aminobutyric acid in depression. PET has generally failed to find a correlation between radioligand binding potential and depression severity or treatment response, though it may offer promise in distinguishing responders and nonresponders to treatment. A major challenge for both modalities is that depression is a heterogeneous, multifactorial disorder, while MR spectroscopy and PET are limited to examining a few metabolites or a single radioligand at a time. This difference makes a comprehensive evaluation of neurochemical changes in the brain difficult., (© 2014 by American Journal of Neuroradiology.)

Published
2014
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