Mass, brain tissues

A delicate balance of normal pressure is maintained in the brain and spinal cord by brain, blood, and cerebrospinal fluid (CSF) volume. Since the brain is contained within a confined space (skull), any foreign mass contained within that space causes adverse sequelae. This results in either destruction or displacement of normal brain tissue with associated edema. Most brain metastases occur through hematogenous spread of the primary tumor, and around 80% of patients will have multiple sites of metastases within the brain. 

J. Gobom, K. O. Kraeuter, R. Persson, H. Steen, P. Roepstorff, and R. Ekman. Detection and Quantification of Neurotensin in Human Brain Tissue by Matrix-Assisted Laser Desorption/ Ionization Time-of-Flight Mass Spectrometry. Anal. Chem., 72(2000) 3320-3326. 

Noto T, Hasegawa T, Kamimura H, Nakao J, Hashimoto H, Nakajima T. 1987. Determination of putrescine in brain tissue using gas chromatography-mass spectrometry. Anal Biochem 160 371-375. 

Pierson J, Norris JL, Aerni HR, Svenningsson P, Caprioli RM, et al. 2004. Molecular profiling of experimental Parkinson s disease direct analysis of peptides and proteins on brain tissue sections by MALDI mass spectrometry. J Proteome... 

Prokai L, Kim HS, Zharikova A, Roboz J, Ma L, et al. 1998. Electrospray ionization mass spectrometric and liquid chromatographic-mass spectrometric studies on the metabolism of synthetic dynorphin A peptides in brain tissue in vitro and in vivo. J Chromatogr A 800 59. 

Cheney et al. (1995) analyzed steroids by coupling an HPLC purification step with GC/MS. The steroids were initially characterized by their HPLC retention times compared with the retention times of tritium-labeled recovery standards. Next, the nemosteroids were characterized by their GC retention times. Finally, they were identified by their unique fragmentation spectra following derivatization with heptafluorobutyric anhydride or methoxyamine hydrochloride. For structmal identification, the mass spectra were compared to appropriate reference standards. This approach is highly specific, and its sensitivity is increased by the use of SIM. The detection limit for measuring allopregnanolone achieved in the 1995 study was 0.63 pmol (0.2 ng) starting from 100-300 mg of brain tissue. 

Liere P, Akwa Y, Engerer SW, Eychenne B, Pianos A, et al. 2000. Validation of an analytical procedure to measure trace amounts of neurosteroids in brain tissue by gas chromatography-mass spectrometry. J Chromatog B 739 301-312. 

The biggest question, arguably, that any scientist or indeed human being can ask, is how the mass of tissue in the brain can generate the inner experience that we call consciousness the state that no one else can access. However articulate, poetic, musical or close to someone you may be, that elusive subjectivity,—the direct first-hand feel of the sun on your face, or the grass between bare toes,—is quintessential personal, utterly subjective. This simultaneously elusive, yet intimate phenomenon has, of course, kept droves of philosophers occupied throughout the ages. But it is only in the last ten or twenty years, that science has actually moved in. 

Hsieh, Y., Casale, R., Fukuda, E., Chen, J., Knemeyer, I., Wingate, J., Morrison, R., and Korfmacher, W. (2006a). Matrix-assisted laser desorption/ionization imaging mass spectrometry for direct measurement of clozapine in rat brain tissue. Rapid Commun. Mass Spectrom. 20 965-972. 

Figure 7. Field desorption mass spectra recorded at 22—23 ma for a biphenyl carbonyl derivative of psychosine and a biphenyl carbonyl derivative of a new compound isolated from human brain tissue. Structure indicated for the unknown was assigned on the basis of this spectrum and chemical evidence relating the unknown to psychosine. Both samples were purified by HPLC prior to FDMS.

The idea that Gq activation leads to stimulation of EC formation is logical given that PLC is known to be activated by this class of G-proteins (Stemweiss et al. 1992). Activation of mGluRs has been shown to increase EC levels measured using mass spectrometric analysis of brain tissue (Jung et al. 2005), and activation of PLC and DAG lipase were implicated in this mGluR action. 

Colsch B, Woods A (2010) Localization and imaging of sialylated glycosphingolipids in brain tissue sections by MALDI mass spectrometry. Glycobiology 20 661-667. doi 10.1093/glycob/ cwq031... 

Jackson S, Wang H, Woods A (2007) In situ structure characterization of glycerophospholipids and sulfatides in brain tissue using MALDI-MS/MS. J Am Soc Mass Spectrom 18 17-26. doi 10.1016/j.jasms.2006.08.015... 

Sjovall P, Lausmaa J, Johansson B (2004) Mass spectrometric imaging of lipids in brain tissue. Anal Chem 76 4271 1278. doi 10.1021/ac049389p... 

McDonnell L, Piersma S, Altelaar A, Mize T, Luxembourg S, Verhaert P, van Minnen J, Heeren R (2005) Subcellular imaging mass spectrometry of brain tissue. J Mass Spectrom 40 160-168. doi 10.1002/jms.735... 

Nemes P, Woods A, Vertes A (2010) Simultaneous imaging of small metabolites and lipids in rat brain tissue at atmospheric pressure by laser ablation electrospray ionization mass spectrometry. Anal Chem 82 982-988. doi 10.1021/ac902245p... 

Jackson S, Ugarov M, Egan T, Post J, Langlais D, Schultz J, Woods A (2007) MALDI-ion mobility-TOFMS imaging of lipids in rat brain tissue. J Mass Spectrom 42 1093-1098. doi 10.1002/jms. 1245... 

Goto-Inoue N, Hayasaka T, Zaima N, Kashiwagi Y, Yamamoto M, Nakamoto M, Setou M (2010) The detection of glycosphingohpids in brain tissue sections by imaging mass spectrometry using gold nanoparticles. J Am Soc Mass Spectrom 21 1940-1943. doi 10.1016/j. jasms.2010.08.002... 

Fig. 5 Discovery metabolite profiling of brain tissue, where mass ion intensity ratios (FAAH / / FAAH+/+) of metabolites are presented on three-dimensional surface plots. Global view of the relative levels of metabolites in FAAH / and FAAH+/+ brains, plotted over a mass range of 200-1,200 m/z and liquid chromatography retention times of 0-105 min (plot shown for negative ionization mode). FAAH / brains possessed highly elevated levels of A-acyl ethanolamines (NAEs) (lipid group 4) and an unknown class of lipids (group 5), identified as A-acyl taurines (NATs). Other lipids, e.g., free fatty acids (group 1), phospholipids (group 2), and ceramides (group 3) were unaltered in these samples...

Polak and Molenaar described a method for the determination of acetylcholine from brain tissue by pyrolysis-gas chromatography-mass spectrometry [200]. The deuterium-labeled acetyl-choline is pyrolytically demethylated with sodium benzenethiolate, followed by quantitative GC-MS analysis. In this method, care must be taken so that the samples do not contain appreciable amounts of choline since exchange of deuterium-labeled groups between acetylcholine and choline during pyrolysis may yield erroneous results. The same authors have also reported a method for the determination of acetylcholine by slow pyrolysis combined with mass fragment analysis on a packed capillary column [201]. 

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