K. Ranga Krishnan, MB ChB

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• Psychiatry

Chair, Department of Psychiatry

Department / Division:
Psychiatry and Behavioral Sciences / Biological Psychiatry

Address:
DUMC 3950
Durham, NC 27710

Appointment Telephone:
919-684-5616

Office Telephone:
919-684-5616

Fax Telephone:
919-681-5489

• MB BS, Madras Medical College, 1978

• Psychiatry, Duke University Medical Center, 1981-1983

• Neurobiology, Duke University Medical Center, 1982-1984

Clinical Interests:
Affective disorders, anxiety disorders, obsessive-compulsive disorders, psychopharmacology, geriatric depression

Research Interests:
I have validated in vivo methods of estimating volumes of subcortical structures utilizing MRI and sterology.  These studies have suggested that depressed patients have smaller caudate, smaller putamen, altered water balance in the hippocampus, a smaller medulla and cerebellar vermis, and enlarged ventricles.  Our group has demonstrated that late-life depression patients have increased MRI lesions in the fronto-parietal white matter and subcortical gray; and, have lesions in the caudate increase the risk of delirium with ECT and antidepressants.  In the last year, we have developed high resolution MR proton spectroscopy methods to measure the concentration of a variety of physico-chemical moieties, including choline, lactic acid, water, glucose, N-acetylaspartate and glutamate in volumes of < one ml.  We are utilizing this technique to study affective disorder, Alzheimer's disease and social phobia and the effect of psychotropic medications on these parameters.  In an initial study, a state dependent increase in choline in depressed patients has been demonstrated; and, in Alzheimer's disease, a reduction in N-acetyl asparatate and an increase in Inositol which progresses as the disease advances.  In addition, we are examining the relationship between fluoxetine concentrations in the brain using MRS and therapeutic efficacy.  We currently use MR methods to assess drug efficacy in various disorders and in the development of new drugs.  We have developed protocols to compare drugs developed for Alzheimer's disease based on their known effects on MRS parameters in dogs.

Representative Publications:
Krishnan KRR: Neuroanatomic substrates of depression in the elderly. Journal Geriatric Psychiatry & Neurology 6 (1): 39-58, 1993. (1993)

Krishnan KRR: Organic bases of depression in the elderly. Annual Review Medicine 42: 261-266, 1991. (1991)

Krishnan KRR, Doraiswamy PM, Lurie SN, Figiel GS, Husain MM, Boyko BO, Ellinwood EH, Nemeroff CB: Pituitary size in depression. Journal Clinical Endocrinology & Metabolism 72: 256-259, 1991. (1991)

Krishnan KRR, Doraiswamy PM, Figiel GS, McDonald WM, Husain MM, Shah SA, Na C, Boyko BO, Nemeroff CB, Ellinwood EH: Hippocampal abnormalities in depression. Journal Neuropsychiatry & Clinical Neurosciences 3 (4): 387-391, 1991. (1991)

Escalona PR, McDonald WM, Doraiswamy PM, Boyko BO, Husain MM, Figiel GS, Laskowitz D, Ellinwood EH, Krishnan KRR: in vivo stereological assessment of human cerebellar volume: Effects of gender and age. American Journal Neuroradiology 12 (5): 927-929, 1991. (1991)