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Research Interests

Dr. Dempsey currently has multiple research projects with focus on cerebral ischemia and brain injury. As a Principal Investigator of grants from the National Institutes of Health, The Veterans Administration and the American Heart Association, Dr. Dempsey leads a group of neurosurgeons and scientists dedicated to neurosurgical patient care.
  The biochemistry of ischemic brain edema and traumatic brain injury.
  Lipid changes and other factors in the formation of carotid artery atherosclerosis.
  The stimulation and modification of adult neuro progenitor stem cells in brain after focal cerebral ischemia.
  Acute management of subarachnoid hemorrhage.
  Applied research in stroke, brain perfusion, subarachnoid hemorrhage and trauma.
  The molecular Biology of Embolic Carotid diseases and its relationship to delayed cognitive impairment.

Several clinical studies are ongoing including studies to look at the pathophysiology of a recurrent stroke, the possibility of supplementing blood flow to the brain after carotid occlusion, the impact of sleep disordered breathing on cerebral vascular regulation, and the modification of interoperative cerebral ischemia with hypothermia.

 


Current Clinical Research

The Carotid Plaque Study is researching structural abnormalities in carotid plaque that can cause it to become unstable and embolize, possible causing silent strokes. Subjects in this study will be recruited from a population of patients who are currently or will be scheduled to undergo carotid endarterectomy at the University of Wisconsin Hospital and Clinics due to the presence of high-grade atherosclerotic cervical internal carotid artery stenosis. Study procedure consist of a research-only MRI that detects if silent strokes have occurred, TCD and carotid ultrasound to map the plaque filled artery and determine what physical characteristics might cause plaque to rupture under the stress of pulsation, a neurocognitive assessment to measure pre-operative cognitive function and compare it to post-operative cognitive function, and blood collection to analyze RNA expression profiles that can be used as biomarkers to identify the patients with a higher risk of plaque instability. Subjects undergo these tests, the cost of which are fully funded by an NIH grant, prior to their clinically indicated CEA, and one year later. Participation in this study does not alter a patient’s standard of care treatment plan.

Publications so far include:

Wang X, Jackson SC, Mitchell CC, Varghese T, Wilbrand SM, Rocque BG, Hermann BP, Dempsey RJ. 
Classification of Symptomatic vs. Asymptomatic Patients with Cognitive Decline using Non-invasive 
Carotid Plaque based Strain Indices as Biomarkers. Ultrasound Med Biol. 2016 Jan 5. pii: S0301-
5629(15)00691-2. doi: 10.1016/j.ultrasmedbio.2015.11.025. [Epub ahead of print] PMID: 26778288.
 
Jackson DC, Sandoval Garcia C, Rocque BG, Wilbrand SM, Mitchell CC, Hermann BP, Dempsey RJ. Cognitive 
Deficits in Symptomatic and Asymptomatic Carotid Endarterectomy Surgical Candidates. Archives of 
Clinical Neuropsychology. 2016 Feb: 31 (1):1-7. Doi: 10.1093/arclin/acv082. Epub 2015 Dec 10. PMID: 
26663810.
 
Berman SE, Wang X, Mitchell CC, Kundu B, Jackson DC, Wilbrand SM, Varghese T, Hermann BP, Howard 
AR, Johnson SC, Dempsey RJ. The relationship between carotid artery plaque stability and white matter 
ischemic injury. Neuroimage: Clinical.  2015 Aug 22; 9:216-22. Doi: 10.1016/j.nicl.2015.08.011. eCollection 
2015. PMID: 26448914 in process. 
 
Wang X, Mitchell CC, Varghese T, Jackson DC, Rocque BG, Hermann BP, Dempsey RJ. Improved Correlation 
of Strain Indices with Cognitive Dysfunction with inclusion of Adventitial Layer with Carotid Plaque. 
Ultrasound Imaging. 2016 May;38(3): 194-208. Doi: 10.1177/0161734615589252. Epub 2015 May 28. 
PMID: 26025578. PMCID: PMC4662918 [Available on 2017-05-01].
 
Wang X, Jackson DC, Mitchell CC, Varghese T, Hermann BP, Kliewer M, Dempsey RJ. Correlation of 
cognitive function with ultrasound strain indices in carotid plaque. Ultrasound Med Biol. 2014 
Jan;40(1):78-89. doi: 10.1016/j.ultrasmedbio.2013.08.001. Epub 2013 Oct 11. PMID: 24120415. PMCID: 
PMC3849143. 
 
Wang X, Jackson DC, Mitchell CC, Varghese T, Hermann BP, Kliewer M, Dempset RJ. Estimation of 
ultrasound strain indices in carotid plaque and correlation to cognitive dysfunction. Conf Proc IEEE Eng 
Med Biol Soc. 2014; 2014:5627-30. doi: 10.1109/EMBC.2014.6944903. PMID: 25571271. PMCID: 
PMC4288023. 
 
McCormick M, Varghese T. An Approach to Unbiased Subsample Interpolation for Motion Tracking. 
Ultrason Imaging. Author manuscript; available in PMC 2014 April 1. Published in final edited form as: 
Ultrason Imaging. 2013 April; 35(2): 10.1177/0161734613476176. doi: 10.1177/0161734613476176. 
PMCID: PMC3656167.
 
Vemuganti R. All's well that transcribes well: non-coding RNAs and post-stroke brain damage. Neurochem 
Int. 2013 Nov;63(5):438-49. doi: 10.1016/j.neuint.2013.07.014. Epub 2013 Aug 15. PMID: 23954844. 
PMCID: PMC3805745.
 
Rocque BG, Jackson DC, Varghese T, Hermann BP, McCormick M, Kliewer M, Mitchell CC, Dempsey RJ. 
Impaired cognitive function in patients with atherosclerotic carotid stenosis and correlation with 
ultrasound strain measurements. J Neurol Sci. 2012 Nov 15;322(1-2):20-4. doi: 10.1016/j.jns.2012.05.020. 
Epub 2012 Jun 1. PMID: 22658531. PMCID: PMC3459178.
 
McCormick M, Varghese T, Wang X, Mitchell CC, Kliewer MA, Dempsey RJ. Methods for robust in vivo 
strain estimation in the carotid artery. Phys Med Biol. 2012 Nov 21;57(22):7329-53. doi: 10.1088/0031-
9155/57/22/7329. Epub 2012 Oct 18. PMID: 23079725. PMCID: PMC3740562.
 
McCormick M, Rubert N, Varghese T. Bayesian Regularization applied to Ultrasound Strain Imaging. IEEE 
Trans Biomed Eng. Author manuscript; available in PMC 2011 June 1. Published in final edited form as: 
IEEE Trans Biomed Eng. 2011 June; 58(6): 1612–1620. Published online 2011 January 17. 
doi: 10.1109/TBME.2011.2106500. PMCID: PMC3092822.
 
McCormick M, Madsen EL, Deaner M, Varghese T. Absolute backscatter measurements of tissue-
mimicking phantoms in the 5-50 MHz frequency range. J Acoust Soc Am. 2011 August; 130(2): 737–743. 
doi: 10.1121/1.3605669. PMCID: PMC3190655.
 
Madsen EL, Frank G, McCormick M, Deaner M, Stiles T. Anechoic sphere phantoms for estimating 3-D 
resolution of very-high-frequency ultrasound scanners. IEEE Trans Ultrason Ferroelectr Freq Control. 
Author manuscript; available in PMC 2013 September 11. Published in final edited form as: IEEE Trans 
Ultrason Ferroelectr Freq Control. 2010 October; 57(10): 2284–2292. doi: 10.1109/TUFFC.2010.1689. 
PMCID: PMC3769966.
 

If you’d like more information about this study, please contact the Plaque Study Research coordinator, Stephanie Wilbrand PhD, at plaquestudy@neurosurgery.wisc.edu

 


Recent Publications

Wesley U, Hatcher J, Ayvaci E, Klemp A, Dempsey RJ.  “Regulation of dipeptidyl peptidase IV in the post-stroke rat brain and In vitro ischemia: Implications for chemokine mediated neural progenitor cell migration and angiogenesis”.  Molecular Neurobiology, Online DOI 10.1007/s12035-016-0039-4, August 2016.
Lopez M, Dempsey RJ, Vemuganti R.  “Resveratrol preconditioning induces cerebral ischemic tolerance, but had no effect on cerebral microRNA profiles”.  Journal of Cerebral Blood Flow & Metabolism, 2016 Jun 20. pii: 0271678X16656202.  
Vemuganti R, Mehta S, Kim T, Dempsey RJ, Lyons K,  Kim T, Mehta S, “Post-stroke induction of α-synuclein mediates ischemic brain damage.  The Journal of Neuroscience.  JN-RM-1241-16R1 – Accepted May, 2016.   
Kim T, Mehta S, Kaimal B, Lyons K, Dempsey RJ, Vemuganti R.  “Post-stroke induction of alpha-synuclein mediates ischemic brain damage.  Accepted, The Journal of Neuroscience, May 2016. 
Wang X, Mitchell CC, Varghese T, Jackson DC, Rocque BG, Hermann BP, Dempsey RJ. Improved Correlation of Strain Indices with Cognitive Dysfunction with inclusion of Adventitial Layer with Carotid Plaque. Ultrasound Imaging. 2015 May 28 doi: 10.1177/0161734615589252. PMID: 26025578, NIHMSID is 704186.
Wesley UV, Hatcher JF, Dempsey RJ. Sphingomyelin Synthase 1 Regulates Neuro-2a Cell Proliferation and Cell Cycle Progression Through Modulation of p27 Expression and Akt Signaling. Mol Neurobiol. 2015 Jun;51(3):1530-41. doi: 10.1007/s12035-014-8829-z. Epub 2014 Aug 2. PMID:25084761.
Li Y, Parmar V, Dempsey RJ, Medow JE.  “Traumatic Brain Injury - Management Principles of Raised Intracranial Pressure and the Emergence of Hypertonic Saline”.
Pharmaceutical Sciences. Accepted December, 2015.
Piquer J, Qureshi M, Young P, Dempsey RJ.   Neurosurgery, Education and Development (NED) Program to Treat Hydrocephalus and to Develop Neurosurgery in Africa, using Mobile Neuroendoscopic Training. Journal of Neurosurgery - Pediatrics. 2015 Mar 6:1-8.
 
Joshi D, Zhang C, et al.  Deletion of Mitochondrial Anchoring Protects Dysmyelinating Shiverer: Implications for Progressive MS.  The Journal of Neuroscience.  April, 2015 Vol 35 (13), pp5293-5409.
 
Lopez M, Dempsey RJ, Vemuganti R.  “Resveratrol Neuroprotection in Stroke and Traumatic CNS Injury”.  Neurochemistry International, .doi.org/10.1016/j.neuint.2015.08.009 August 2015
 
Park K, Johnson W, Dempsey RJ.  “Global Neurosurgery: The Unmet Need”.  World Neurosurgery. doi: 10.1016/j.wneu.2015.12.048.  Online 28 Dec 2015. 
Kalluri  HS, Dempsey RJ.  D609-mediated inhibition of ATP synthesis in neural progenitor cells.  NeuroReport 25 (10), 777-781, 2014.
 
Sedney CL, Siu J, Rosseau G, Dempsey RJ, Bernstein, M.  International neurosurgical volunteerism: a temporal, geographical, and thematic analysis of FIENS volunteer reports.  World Neurosurgery Aug S1878-8750(14)00700-701.  2014. 
 
Zhang RR, Pointer KB, Kuo JS, Dempsey RJ.  Mutational analysis reveals the origin and therapy-driven evolution of recurrent glioma.   Neurosurgery. 2014 Dec; 75(6):N9-10.
 
Wesley UV, Resad E, Dempsey RJ.  “Hypoxia inducible factor regulation of galectin3 expression in neuroblastoma cells: Implications in controlling malignant phenotype of neuroblastoma cells”.  Cancer Research 74 (19 Supplement), 1111. 2014.
 
Kahamba J, Assey A, Dempsey R, Qureshi M, Härtl, R.  The Second African Federation of Neurological Surgeons Course in the East, Central, and Southern Africa Region Held in Dar es Salaam, Tanzania, January 2011.  World Neurosurgery Sep-Oct;80 (3-4):255-9.  2013.
 
Dempsey R, Nakaji P.  FIENS Global Health and Neurosurgical Volunteerism.  Neurosurgery,  73 (6), 1070-1071.  2013.
 
Kahamba J, Assey A, Dempsey R, Qureshi M, Härtl, R.  The Second African Federation of Neurological Surgeons Course in the East, Central, and Southern Africa Region Held in Dar es Salaam, Tanzania, January 2011.  World Neurosurgery 2013 80 (3):255-259.  2013.
 
Pointer KB, Zhang RR, Kuo JS, Dempsey RJ.  Detecting Brain Tumor With Raman Scattering Microscopy.  Neurosurgery 74 (2), N12-N14, 2013.
Kalluri HS, Gusain A, Dempsey RJ. Regulation of neural progenitor cell proliferation by D609: potential role for ERK. Mol Neurobiol. 2013 Apr;47(2):782-9. doi: 10.1007/s12035-012-8390-6. Epub 2012 Dec 30. PMID:23275176.
Wesley UV, Vemuganti R, Ayvaci ER, Dempsey RJ. Galectin-3 enhances angiogenic and migratory potential of microglial cells via modulation of integrin linked kinase signaling. Brain Res. 2013 Feb 16;1496:1-9. doi: 10.1016/j.brainres.2012.12.008. Epub 2012 Dec 14. PMID: 23246924.
Gusain A, Hatcher JF, Adibhatla RM, Wesley UV, Dempsey RJ. Anti-proliferative effects of tricyclodecan-9-yl-xanthogenate (D609) involve ceramide and cell cycle inhibition. Mol Neurobiol. 2012 Jun;45(3):455-64. doi: 10.1007/s12035-012-8254-0. Epub 2012 Mar 14. Erratum in: Mol Neurobiol. 2012 Jun;45(3):465. PMID:22415444.
Kalluri HS, Dempsey RJ. Osteopontin increases the proliferation of neural progenitor cells. Int’l Journal of Developmental Neuroscience 30(5):359-62, 2012.
Plante M, Arscott WT, Folsom J, Tighe S, Dempsey RJ, Wesley U. Ethanol promotes cytotoxic effects of Tumor Necrosis Factor Related Apoptosis-Inducing Ligand through induction of reactive oxygen species in prostate cancer cells. Prostate Cancer and Prostatic Diseases 16(1): 16-22, 2012.
Kalluri HS, Dempsey RJ. Regulation of cell cycle by IGFBO3. Neurochem Res. 36(3):406-11, 2011.
Bowen K, Dempsey RJ, Vemuganti R. Adult interleukin-6 knockout mice show compromised neurogenesis. NeuroReport 22:126-130, 2011.
Tureyen K, Bowen K, Liang J, Dempsey RJ, Vemuganti R. Exacerbated brain damage, edema and inflammation in type-2 diabetic mice subjected to focal ischemia. Journal of Neurochemistry 116:499-507, 2011.
Nakka V, Lang B, Lenschow D, Zhang D, Dempsey RJ, Vemuganti R. Increased Cerebral Protein ISGlylation after Focal Ischemia is Neuroprotective. Journal of Cerebral Blood Flow & Metabolism 31(12):2375-12384, 2011.
Dempsey RJ. Art, Passion and Neurosurgery: Presidential address from the Society of Neurological Surgeons., June 10. World Neurosurgery 76(5): 378-384. 2011.
Dempsey RJ, Vemuganti RL, Varghese T, Hermann BP. A review of Carotid Atherosclerosis and Vascular Cognitive Decline: A new Understanding of the Keys to Symptomatology. Neurosurgery 67 (2) 484-493, 2010.
Kundu B, Kuo JS, Dempsey RJ. Turning everything into brain? Neurosurgery 67(2):2N16-17, 2010.

 


Book Chapters

Haldeman D, Dempsey RJ.  Intracranial Neoplasms in the Elderly.  Accepted, Hazzard’s Textbook of Geriatrics and Gerontology.  December 2014.  

Bauer A, Dempsey R.  The Pathophysiology of Cerebral Ischemia.  Accepted, Neurovascular Surgery, 2nd Edition, Chapter III, pgs 203-215.  October 2014. 

McCormick, M,  Dempsey, R,  Varghese, T,  Mitchell, C,  Kliewer M.  “Noninvasive Measurement of Pulsatile Carotid Plaque Deformation by Strain Tensor Ellipses: Possible Determinate of Symptomatology”  Book of Proceedings (NX23) of the of ICCAD 2011 (October 23-26, 2011, Venice, Italy)

Yan Y, Vemuganti R, Dempsey RJ.  Post-ischemic Neurogenesis and Brain Repair:  Growth Factors and Cytokines.  e-Book:  Experimental Stroke.  2011, eISBN 978-1-60805-001-7


Abstracts

Wesley UV, Hatcher JF, Chagharvand S, Wilbrand SM, Dempsey RJ. Adipokines as 
novel/potential biomarkers in the secretome of atherosclerotic patients: Association of 
lipocalin-2 with age, obesity, and plaque stability. Submitted to ISC 2017 on August 15th,2016.
 
Mitchell CC, Wilbrand SM, Steffel CN, Varghese T, Meshram N, Li G, Cook TD, Salamat S, 
Dempsey RJ. Transcranial Doppler and Microemboli Detection: Relationship to Symptomatic 
Status and Histopathology Findings. Submitted to ISC 2017 on August 10th, 2016.
 
Dempsey RJ, Varghese T, Hermann BP, Jackson DC, Berman SE, Johnson S, Mitchell CC, Wilbrand SM, Wang X, Rocque B, Vemuganti R. Carotid Plaque Instability is more important than degree of Stenosis in Assessing Surgical Candidates. Oral presentation at the Neurosurgical Society of America Annual Meeting, Dublin, Ireland June 19-22, 2016.
 
Mitchell CC, Stein JH, Cook TD, Salamat S, Wang X, Varghese T, Jackson DC, Sandoval Garcia C, Wilbrand SM, Dempsey RJ. Histopathological Validation of Novel Gray Scale Carotid Plaque Characteristics Related to Plaque Vulnerability. Abstract accepted for a Ted Talk to the Department of Medicine Medical Research Day, University of Wisconsin on June 3rd, 2016.
 
Mitchell CC, Stein JH, Cook TD, Salamat S, Wang X, Varghese T, Jackson DC, Sandoval Garcia C, Wilbrand SM, Dempsey RJ. Histopathological Validation of Novel Gray Scale Carotid Plaque Characteristics Related to Plaque Vulnerability. Abstract accepted for poster presentation to the American Society of Echocardiography (ASE), June 2016.
 
Meshram NH, Wang X, Jackson DC, Mitchell CC, Varghese T, Wilbrand SM, Dempsey RJ. Correlation of cognitive function with strain indices for accessing carotid plaque instability. (oral presentation), Proceedings of the 61st Annual convention, American Institute of Ultrasound in Medicine, New York Hilton Midtown, 1335 Avenue of the Americas, New York, New York, March 17-21, 2016.
 
Wang X, Jackson DC, Mitchell CC, Varghese T, Wilbrand SM, Rocque BG, Hermann BP, Dempsey RJ. Strain based vascular biomarkers for classification of patients with cognitive impairment. (oral presentation), Proceedings of the 61st Annual convention, American Institute of Ultrasound in Medicine, New York Hilton Midtown, 1335 Avenue of the Americas, New York, New York, March 17-21, 2016.
 
Mitchell CC, Stein JH, Cook TD, Salamat S, Wang X, Varghese T, Jackson DC, Sandoval Garcia C, Wilbrand SM, Dempsey RJ. Histopathological Validation of Novel Gray Scale Carotid Plaque Characteristics Related to Plaque Vulnerability. Submitted abstract to American Heart Association Meeting, Nov. 2015.
 
Dempsey RJ, Baggott C, Sandoval Garcia C, Jackson DC, Mitchell CC, Wilbrand SM. Reduction of Brain Microemboli one year after Carotid Endarterectomy. 15th Interim Meeting of the World Federation of Neurological Societies. Rome (Italy), September 2015.
 
Dempsey R, Baggott C, et al.  Brain Barriers and CNS Pathologies.  Abstract accepted for CVB2015, Paris (France), July 2015.  
 
Dempsey RJ, Wilbrand SM, Baggott C, Sandoval Garcia C, Jackson DC, Mitchell CC, Wang X, Varghese T, Berman S, Johnson S, Salamat S, Tureyen K, Vemuganti R. Vascular Wall Microvessels as a Determinant of Plaque Instability in Stroke. Abstract presented at the 11th International Conference on Cerebral Vascular Biology, Paris (France), July 2015.
 
Vemuganti R, Mehta SL, Jackson D, Dempsey RJ. Blood RNA Biomarkers of Stroke 
Symptomatology in Carotid Atherosclerotic Patients. Presented at Eurostroke, Vienna, May 
2015.
 
Berman S, Sterling J, Dempsey R, et. al.  Internal carotid artery plaque strain is a predictor of brain white matter hyperintensity lesion burden.  Poster presentation at the American Society for Clinical Investigations / Association of American Physicians / American Physics Scientist Association Joint Conferences. Chicago IL, April 2015. 
 
UV Wesley, E Resad, RJ Dempsey.  Hypoxia inducible factor regulation of galectin3 expression in neuroblastoma cells: Implications in controlling malignant phenotype of neuroblastoma cells. Cancer Research 74 (19 Supplement), 1111. 2014
 
Wesley U, Dempsey R.  “Neuronal Cell Migration” Accepted abstract for presentation at Neuroscience Nov. 2014. 
 
Wesley U, Resad E, Clark P, et. al.  Glioblastoma Invasion.  Abstract submitted to American Association for Cancer Research.  December, 2014.
 
Wang X, Salamat S, Varghese T, Dempsey RJ. Characterization of Carotid Plaque with Histology 
and Quantitative Ultrasound. Oral presentation at the 55th Annual Meeting of the American 
Association of Physicists in Medicine (AAPM). Indianapolis, Indiana, August 4-8, 2013.
 
Wang X, Mitchell CC, Jackson DC, Varghese T, Hermann BP, Kliewer MA, Dempsey RJ. Correlation 
of Cognitive Function with Ultrasound Strain Indices. Oral presentation at the 55th Annual 
Meeting of the American Association of Physicists in Medicine. Indianapolis, Indiana, August 4-8, 
2013.
 

 



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