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Importance of measuring products of non-enzymatic glycation of proteins   总被引:6,自引:0,他引:6  
Non-enzymatic glycation products are a complex and heterogeneous group of compounds which accumulate in plasma and tissues in diabetes and renal failure. There is emerging evidence that these compounds may play a role in the pathogenesis of chronic complications associated with diabetes and renal failure. So measurement of the products of non-enzymatic glycation has a twofold meaning: on one hand, measurement of early glycation products can estimate the extent of exposure to glucose and the subject's previous metabolic control; on the other hand, measurement of intermediate and late products of the glycation reaction is a precious instrument in verifying the relationship between glycation products and tissue modifications. This review summarizes current knowledge about the diagnostic utility of measuring non-enzymatic glycation products.  相似文献
高危新生儿遗传代谢病临床病因学分析   总被引:4,自引:2,他引:2  
目的 初步研究新生儿重症监护室(NICU)先天性遗传代谢病(IEM)高危新生儿的临床病因学.方法 应用气相色谱-质谱联用分析法(GC/MS)对100 例临床IEM 高危新生儿进行新鲜晨尿有机酸分析,并查血常规、肝肾功能、乳酸、丙酮酸、β-羟丁酸、血氨和同型半胱氨酸,其中24 例患儿尿有机酸分析结果阳性,临床拟诊为IEM,对临床拟诊为IEM 的24 例患儿进行1 ~2 个疗程的治疗,之后复查GC/MS 尿有机酸分析.结果 24 例临床拟诊为IEM 的患儿12 例确诊为IEM,其中丙酮酸血症、酪氨酸血症和同型半胱氨酸血症各2 例,甲基丙二酸尿症、戊二酸血症Ⅱ型、乳糖不耐症、高甲硫氨酸血症、β-酮硫解酶缺乏症和鸟氨酸氨甲酰转移酶缺乏症各1 例,均呈常染色体隐性遗传.12 例IEM 患儿的临床表现各不相同,其中血管病变3 例(微血栓形成1 例和脑实质内出血2 例),新生儿惊厥和复发性代谢性酸中毒各2 例,新生儿猝死、难治性低血糖、顽固性腹泻、遗传相关性高胆红素血症和重症肺炎各1 例.12 例IEM 患儿的疾病极期,100%出现高氨血症,83%出现丙酮酸血症,67%出现肾损害和代谢性酸中毒,50%出现肝损害,42%出现血液系统损害.结论 高危新生儿IEM 临床病因复杂,随着新技术的发展,新生儿IEM 疾病谱不断扩大,进一步揭示了高危新生儿病因,为临床诊治提供依据.  相似文献
同位素稀释气相色谱质谱法测定血清总胆固醇   总被引:1,自引:1,他引:0  
目的建立一种新的同位素稀释-气相色谱-质谱(ID/GC/MS)测定人血清总胆固醇的方法。方法取一定量的血清样品与[3,4-^13 C2]-胆固醇内标溶液充分混匀,水解并提取溶液中的胆固醇后,用N,O-二-(甲基硅烷)三氟乙酰胺(BSTFA)衍生胆固醇为三甲基硅烷醚;气相色谱.四极杆质谱(GC/MS)选择检测目标离子。检测标准溶液和血清样品的m/z368和m/z370的离子强度并积分,校正标准溶液中天然同位素胆固醇对内标的影响,将校正后的胆固醇和内标的m/z368和m/z370面积比对胆固醇标准溶液浓度做线性回归。用拟合的回归方程定量血清样品胆固醇浓度。结果建立的ID/GC/MS测定胆固醇的方法平均批内变异系数0,04%~0.81%。分析美国国家标准物质与技术研究所(NIST)2个浓度水平的标准血清SRM1951a,相对偏差分别是0.19%和0.90%。结论建立的ID/GC/MS测定胆固醇的方法操作简单、精密,可以用做血清胆固醇的准确定量。  相似文献
甲基丙二酸血症45例综合报道   总被引:1,自引:0,他引:1  
目的:探讨甲基丙二酸血症的早期诊断及治疗干预方法。方法:总结国内外45例甲基丙二酸血症患儿的临床症状和实验室检查情况,分析其诊治及转归情况。结果:对有不明原因酸中毒,意识障碍,惊厥,肌张力低下以及体格及智力发育落后甚至倒退的患儿应引起高度重视,血尿气相色谱/质谱联用分析(GC/MS)可确诊该病,该病的治疗可分为维生素B12(VB12)有效型及无效型两类,维生素B12有效型可采用VB12注射及限制饮食的方法进行干预;对维生素B12无效型患者采取饮食限制的方法加以干预,晚期肾功能衰竭行肝肾移植可改善此类患儿预后,但不确定是否能改善远期预后。结论:对疑似患儿及时进行GC/MS尿有机酸分析可早期诊断本症,对确诊本病的患儿进行早期干预可明显改善预后。  相似文献
The mammalian lignans enterolactone and enterodiol are regular constituents of human urine and are excreted daily in μmol amounts. They are produced by metabolic action of intestinal bacteria from natural plant lignan precursors which are constituents of various food plants. However, natural plant lignans seem to occur very seldom in detectable amounts in human urine. The present investigation shows that only in 5% of the 150 diphenolic fractions extracted from the urine of women plant lignans other than the previously identified matairesinol could be found. The lignans lariciresinol, isolariciresinol and secoisolariciresinol were identified for the first time by comparison of their GC characteristics and mass spectra with the corresponding results of authentic synthesized reference compounds. Secoisolariciresinol is one natural precursor of the mammalian lignan enterodiol. Of the two other plant lignans, no animal or human metabolic products are known. The occurrence of chemically unchanged plant lignans in some cases in human urine could be a result of an insufficient metabolic capacity of intestinal bacteria, resulting in a decreased detoxification of phenolic plant products.  相似文献
Background: Fatty acid ethyl esters (FAEEs) are useful markers of ongoing alcohol use and may be associated with alcohol-induced damage to the liver and pancreas. In this article, we describe a novel method for rapid determination of the three major FAEEs found in human plasma. Methods: Internal standard, ethyl heptadecanoate, was added to plasma samples, and FAEEs were isolated by acetone precipitation, hexane lipid extraction, and amino-propyl silica solid phase extraction. FAEEs were quantitated by gas chromatography-mass spectrometry (GC-MS) using a nonpolar dimethylpolysiloxane column. The accuracy, precision, specificity, and sensitivity of the assay were defined from plasma samples from recently drinking and abstinent persons, with and without the addition of FAEEs. Results: Individual FAEE peaks demonstrated excellent resolution. Instrument time was reduced by more than 60%. The lower limit of detection was 5 to 10 nM, and the lower limit of quantitation for each FAEE was 60 nM (for 22 samples with known concentration 60 nM, x +/-SD: 61 +/- 5.7, 57 +/- 5.7, and 57 +/- 5.9 nM, for ethyl palmitate, ethyl oleate, and ethyl stearate, respectively). Instrument precision (coefficient of variance, CV) for these three FAEEs was 0.3%, 0.4%, and 0.7%, respectively. Intra-assay precision (CV) for total FAEEs was less than 7%. FAEEs were absent in 49 samples from abstinent persons. FAEEs were detected in all 76 samples with associated positive blood alcohol levels. Conclusions: Our method of FAEE analysis is rapid and potentially useful in research and clinical studies. FAEE determination using this method is precise, accurate, sensitive, and specific and deserves broader application.  相似文献
BACKGROUND: Recent evidence has shown that hyperglycemia is able to cause increased production of superoxide on the mitochondrial transport chain, and that this is the key event which activates some events such as increased AGE formation, increased hexosamine and polyol flux, and activation of PKC, all believed to be important for the development of the chronic complications of diabetes, aging and uremia. In this context, non-enzymatic protein glyco-oxidation leads to the formation of a series of products whose intra- and extra-cellular accumulation is of key importance in the pathogenesis of these chronic diseases. METHODS: Various spectrometric approaches, such as matrix-assisted laser desorption ionisation (MALDI), and liquid chromatography-electrospray ionisation (ESI) were used. RESULTS AND CONCLUSIONS: The latest mass spectrometric approaches have shown their power in proteomics, and we report here some applications of this technique in the study of in vitro and in vivo non-enzymatic protein glyco-oxidation.  相似文献
BACKGROUND/METHOD: The analytical validity of free testosterone (FTe) analog immunoassays is subject to much controversy. We revisited the validation of 4 analog assays and 1 FTe calculation procedure with a metrologically traceable reference measurement procedure (RMP) based on ultrafiltration and isotope dilution-mass spectrometry for direct measurement of Te in the ultrafiltrate. To this end, we performed split-sample measurements of 40 male sera. RESULTS: Deming regression showed that 3 of the immunoassays had moderate to good correlation (0.8474 < or = r < or = 0.9241) with the RMP; however, the slope was markedly below 1. The FTe calculation procedure was in good agreement with this result. The Sy/x values for all assays were higher than the combined imprecision values, which indicate their susceptibility to matrix-related effects. CONCLUSIONS: The study demonstrated substantial differences in analytical quality of FTe assays; however, the results suggested that after extending the validation with a larger variety of samples, recalibration of some analog assays might be worth further investigation.  相似文献
Ifosfamide-induced nephrotoxicity adversely affects the health and well-being of children with cancer. We have recently shown age-dependent nephrotoxicity induced by ifosfamide, with younger children (<3 years) substantially more vulnerable. The mechanisms leading to this age-related ifosfamide-induced renal damage have not been identified. Underlying this work is the hypothesis that renal ontogeny is involved in the expression and activity of the cytochrome P450 (CYP) enzymes responsible for IF metabolism to the nephrotoxic chloroacetaldehyde. We evaluated renal CYP3A and 2B22 activity in pigs between the ages of 1 day and adulthood, as well as the metabolism of ifosfamide by renal microsomes to 2- and 3-dechloroethylifosfamide (2-DCEIF and 3-DCEIF, respectively). Kidney CYP3A messenger RNA expression peaked 15 to 60 days (0.7-76 +/- 0.19 CYP3A/actin ratio; P < 0.001). Subsequently, this level decreased to adult values (0.54 - 0.03 CYP3A/actin ratio; P = 0.04). Similarly, we detected an increase in the ifosfamide-metabolism rate between young (18 +/- 2 pmol/mg protein/min) and adult (12.2 +/- 0.17 pmol/mg protein/min) animals (P = 0.002). Ours is the first documentation of ontogeny of renal CYP3A and of renal ifosfamide metabolism. These data suggest that age-dependent ifosfamide nephrotoxicity is, at least in part, due to ontogeny in the production chloroacetaldehyde.  相似文献
Ifosfamide (IF) improves survival in children with solid tumors but causes a high rate of nephrotoxicity. We hypothesized that this is caused by an oxidative metabolite of IF, chloroacetaldehyde, which is produced locally by the cells of the renal tubule (RT). For this hypothesis to be viable, one must document that chloroacetaldehyde concentrations in the RT cell are consistent with levels shown to cause nephrotoxicity in experimental systems. Using pharmacokinetic modeling of experimental data, we show that the median level of chloroacetaldehyde in RT cells is 80 micromol/L, ranging from 35 to 320 micromol/L. These concentrations are consistent with levels shown experimentally to cause functional and structural RT damage and lends validity to the hypothesis that local renal production of chloroacetaldehyde causes nephrotoxicity.  相似文献
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