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Sarma MK, Nagarajan R, Macey PM, Kumar R, Villablanca JP, Furuyama J, Thomas MA. Accelerated echo-planar J-resolved spectroscopic imaging in the human brain using compressed sensing: a pilot validation in obstructive sleep apnea. AJNR Am J Neuroradiol 2014; 35:S81-9. [PMID: 24503554 PMCID: PMC4077940 DOI: 10.3174/ajnr.a3846] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND AND PURPOSE Echo-planar J-resolved spectroscopic imaging is a fast spectroscopic technique to record the biochemical information in multiple regions of the brain, but for clinical applications, time is still a constraint. Investigations of neural injury in obstructive sleep apnea have revealed structural changes in the brain, but determining the neurochemical changes requires more detailed measurements across multiple brain regions, demonstrating a need for faster echo-planar J-resolved spectroscopic imaging. Hence, we have extended the compressed sensing reconstruction of prospectively undersampled 4D echo-planar J-resolved spectroscopic imaging to investigate metabolic changes in multiple brain locations of patients with obstructive sleep apnea and healthy controls. MATERIALS AND METHODS Nonuniform undersampling was imposed along 1 spatial and 1 spectral dimension of 4D echo-planar J-resolved spectroscopic imaging, and test-retest reliability of the compressed sensing reconstruction of the nonuniform undersampling data was tested by using a brain phantom. In addition, 9 patients with obstructive sleep apnea and 11 healthy controls were investigated by using a 3T MR imaging/MR spectroscopy scanner. RESULTS Significantly reduced metabolite differences were observed between patients with obstructive sleep apnea and healthy controls in multiple brain regions: NAA/Cr in the left hippocampus; total Cho/Cr and Glx/Cr in the right hippocampus; total NAA/Cr, taurine/Cr, scyllo-Inositol/Cr, phosphocholine/Cr, and total Cho/Cr in the occipital gray matter; total NAA/Cr and NAA/Cr in the medial frontal white matter; and taurine/Cr and total Cho/Cr in the left frontal white matter regions. CONCLUSIONS The 4D echo-planar J-resolved spectroscopic imaging technique using the nonuniform undersampling-based acquisition and compressed sensing reconstruction in patients with obstructive sleep apnea and healthy brain is feasible in a clinically suitable time. In addition to brain metabolite changes previously reported by 1D MR spectroscopy, our results show changes of additional metabolites in patients with obstructive sleep apnea compared with healthy controls.
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Affiliation(s)
- M K Sarma
- From the Departments of Radiological Sciences (M.K.S., R.N., R.K., J.P.V., J.F., M.A.T.)
| | - R Nagarajan
- From the Departments of Radiological Sciences (M.K.S., R.N., R.K., J.P.V., J.F., M.A.T.)
| | - P M Macey
- School of Nursing (P.M.M.), University of California, Los Angeles, Los Angeles, California
| | - R Kumar
- From the Departments of Radiological Sciences (M.K.S., R.N., R.K., J.P.V., J.F., M.A.T.)Anesthesiology (R.K.), David Geffen School of Medicine
| | - J P Villablanca
- From the Departments of Radiological Sciences (M.K.S., R.N., R.K., J.P.V., J.F., M.A.T.)
| | - J Furuyama
- From the Departments of Radiological Sciences (M.K.S., R.N., R.K., J.P.V., J.F., M.A.T.)
| | - M A Thomas
- From the Departments of Radiological Sciences (M.K.S., R.N., R.K., J.P.V., J.F., M.A.T.)
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Nagarajan R, Sarma MK, Thomas MA, Chang L, Natha U, Wright M, Hayes J, Nielsen-Saines K, Michalik DE, Deville J, Church JA, Mason K, Critton-Mastandrea T, Nazarian S, Jing J, Keller MA. Neuropsychological function and cerebral metabolites in HIV-infected youth. J Neuroimmune Pharmacol 2012; 7:981-90. [PMID: 23065459 PMCID: PMC3557531 DOI: 10.1007/s11481-012-9407-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 09/18/2012] [Indexed: 12/14/2022]
Abstract
The effects of HIV on brain metabolites and cognitive function are not well understood. Sixteen HIV+youths (15 vertical, 1 transfusion transmissions) receiving combination antiretroviral therapy and 14 age-matched HIV- youths (13-25 years of age) were evaluated with brain two-dimensional (2D) magnetic resonance spectroscopy (MRS) at 3 Tesla (T) and a neuropsychological battery that assessed three cognitive domains (attention/processing speed, psychomotor ability, and executive function). The relationship between brain metabolite ratios and cognitive performance was explored. Compared to HIV- controls, HIV+ subjects had higher sycllo-inositol (Scy)/total creatine (tCr) (+32%, p = 0.016) and higher Scy/total choline (tCho) (+31%, p = 0.018) on 2D-MRS in the right frontal lobe. HIV+ subjects also had higher glutamate (Glu)/tCr (+13%, p = 0.022) and higher Glu/tCho (+15%, p = 0.048) than controls. HIV+ subjects demonstrated poorer attention/processing speed (p = 0.011, d = 1.03) but similar psychomotor and executive function compared to HIV- controls. The attention/processing score also correlated negatively with the ratio of N-acetylaspartate (NAA) to tCr on 2D-MRS (r = -0.75, p = 0.0019) in the HIV- controls, but not in the HIV+ subjects (Fisher's r-z transformation, p < 0.05). Our results suggest that attention/processing speed is impacted by early HIV infection and is associated with right hemisphere NAA/tCr. Scy and Glu ratios are also potential markers of brain health in chronic, lifelong HIV infection in perinatally infected youths receiving antiretroviral therapy.
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Affiliation(s)
- R. Nagarajan
- David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA, USA
| | - M. K. Sarma
- David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA, USA
| | - M. A. Thomas
- David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA, USA
| | - L. Chang
- University of Hawaii, Honolulu, HI, USA
| | - U. Natha
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - M. Wright
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - J. Hayes
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - K. Nielsen-Saines
- David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA, USA
| | - D. E. Michalik
- Miller’s Children’s Hospital of Long Beach, Long Beach, CA, USA
| | - J. Deville
- David Geffen School of Medicine at University of California at Los Angeles, Los Angeles, CA, USA
| | - J. A. Church
- Children’s Hospital Los Angeles, Los Angeles, CA, USA
| | - K. Mason
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - T. Critton-Mastandrea
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - S. Nazarian
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - J. Jing
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - M. A. Keller
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Pediatrics, Harbor-UCLA Medical Center, 1000 West Carson Street, Liu Building, RB3, Box 467, Torrance, CA 90509, USA
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Yasodhara P, Ramalakshmi BA, Sarma MK. A new approach to differentiate recent vs chronic Toxoplasma infection: avidity ELISA in Toxoplasma serology. Indian J Med Microbiol 2001; 19:145-8. [PMID: 17664818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The diagnosis of toxoplamosis during pregnancy is based on maternal serology, due to the asymptomatic nature of the disease. Detection of specific IgM although is the method used all over the world to detect acute infection, persistence of IgM for long periods poses problems in distinguishing acute from chronic infection, which is of crucial importance in pregnancy. Avidity ELISA is a method recently developed to distinguish IgG antibodies developed at an early stage of infection from those that reflect past immunity. The avidity assay uses protein-denaturing agents and is a modification of an ELISA. The usefulness of this technique was tested on sera of 113 pregnant women screened for Toxoplasma specific IgG/IgM antibodies. Nine of the sixteen sera positive for IgM/IgG antibodies and three sera positive for IgG alone were subjected to avidity ELISA. Only three sera were positive for low avidity IgG indicative of recent infection. All the three sera positive for IgG alone showed high avidity.
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Affiliation(s)
- P Yasodhara
- National Institute of Nutrition, Indian Council of Medical Research, Jamai Osmania PO, Hyderabad - 500 007, India
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Sitaramam V, Sarma MK. Gravitational field enhances permeability of biological membranes to sucrose: an experimental refutation of sucrose-space hypothesis. Proc Natl Acad Sci U S A 1981; 78:3441-5. [PMID: 6943551 PMCID: PMC319584 DOI: 10.1073/pnas.78.6.3441] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Isotonic conditions for the integrity of subcellular organelles are shown to be remarkably influenced by the concentration of sucrose present during their isolation by centrifugation. Using the technique of enzyme osmometry, we show that the content of sucrose in synaptosomes reflects nearly total equilibration across the membrane during centrifugation, due to altered permeability of membranes. Presence of sucrose in the matrix space of mitochondria, as demonstrated by enzyme osmometry of matrix enzymes, indicates that the sucrose-space hypothesis is invalid.
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