Candiota A P, Majós C, Bassols A, Cabañas M E, Acebes J J, Quintero M R, Arús C
Departament de Bioquímica i Biologia Molecular, Unitat de Bioquímica de Ciències Edifici Cs, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain.
MAGMA. 2004 Sep;17(1):36-46. doi: 10.1007/s10334-004-0043-y. Epub 2004 Aug 31.
MRI and MRS are established techniques for the evaluation of intracranial mass lesions and cysts. The 2.03 ppm signal recorded in their (1)H-MRS spectra is often assigned to NAA from outer volume contamination, although it has also been detected in non-infiltrating tumours and large cysts. We have investigated the molecular origin of this resonance in ten samples of cystic fluids from human brain tumours. The NMR detected content of the 2.03 ppm resonance in 136 ms echo time spectra, assuming an N- CH(3) origin, was 3.19 +/- 1.01 mM. Only one third (34 +/- 12%) of the N-acetyl containing compound (NAC) signal could be extracted by perchloric acid (PCA) indicating that most of it originated in a macromolecular PCA-insoluble component. Chemical analysis of the cyst fluids showed that sialic acid bound to macromolecules would account for 64.3% and hexuronic containing compounds for 29.2% of the NMR-detectable ex vivo signal, 93.4% of the signal at TE 136 ms. Lactate content measured by NMR (6.4 +/- 4.4 mM) and the predominance of NAC originating in sialic acid point to a major origin from tumour rather than from plasma for this 2.03 ppm resonance.
磁共振成像（MRI）和磁共振波谱（MRS）是评估颅内肿块病变和囊肿的成熟技术。在其氢质子磁共振波谱（1H-MRS）中记录的2.03 ppm信号通常被认为是由于外部容积污染导致的N-乙酰天门冬氨酸（NAA）信号，尽管在非浸润性肿瘤和大囊肿中也检测到了该信号。我们研究了来自人脑肿瘤的10份囊液样本中该共振信号的分子来源。假设其来源为N-CH(3)，在136 ms回波时间谱中，通过核磁共振检测到的2.03 ppm共振信号的含量为3.1.19±1.01 mM。高氯酸（PCA）仅能提取三分之一（34±12%）的含N-乙酰基化合物（NAC）信号，这表明其大部分来源于大分子的PCA不溶性成分。囊液的化学分析表明，与大分子结合的唾液酸占核磁共振可检测到的离体信号的64.3%，含己糖醛酸的化合物占29.2%，在TE为136 ms时占信号的93.4%。通过核磁共振测量的乳酸含量为（6.4±4.4 mM），且NAC主要来源于唾液酸，这表明该2.03 ppm共振信号主要来源于肿瘤而非血浆。
