Johnston Andrea N, Center Sharon A, McDonough Sean P, Warner Karen L
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Am J Vet Res. 2009 Dec;70(12):1502-11. doi: 10.2460/ajvr.70.12.1502.
OBJECTIVE-To determine whether metal concentrations in canine liver specimens were influenced by specimen size, assay variability, tissue processing (formalin fixation and deparaffinization), or storage in paraffin blocks. SAMPLE POPULATION-Liver specimens (fresh frozen and deparaffinized) from 2 dogs with chronic hepatitis (high copper but unremarkable iron concentration [liver 1] and unremarkable copper but high iron concentration [liver 2]) as well as fresh and deparaffinized-archived liver specimens from 20 dogs with various hepatopathies. PROCEDURES-Fresh frozen liver specimens (obtained via simulated needle-core and wedge biopsy), fresh hepatic tissue, and deparaffinized-archived specimens (0.5 to 14 years old) were analyzed for concentrations of copper, iron, and zinc by atomic absorption flame spectrometry. Clinical severity scores were assigned on the basis of tissue metal concentrations. RESULTS-Interassay variation of metal standards was < 4%. Measurements of liver tissues on 8 consecutive days yielded high coefficients of variation (3.6% to 50%) reflecting heterogenous histologic metal distribution; variation was highest in liver 1 and deparaffinized-archived tissues. Heterogenous metal distribution was confirmed by histologic evaluation. The largest range of metal concentrations was detected in wedge biopsy specimens. In tissues with high metal concentrations, copper and iron concentrations were significantly lower in needle-core versus wedge biopsy specimens. A higher zinc concentration in deparaffinized-archived specimens masked a low zinc concentration in fresh liver tissue of 10 of 20 (50%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE-Retrospective measurement of copper and iron concentrations but not zinc concentrations in deparaffinized-archived liver specimens provided relevant information. The value of needle-core biopsy specimens for measurement of metal concentrations is questionable.
目的——确定犬肝脏标本中的金属浓度是否受标本大小、检测变异性、组织处理（福尔马林固定和脱石蜡）或石蜡块储存的影响。样本群体——来自2只患有慢性肝炎的犬的肝脏标本（新鲜冷冻和脱石蜡的）（一只铜含量高但铁浓度无异常[肝脏1]，另一只铜含量无异常但铁浓度高[肝脏2]）以及来自20只患有各种肝病的犬的新鲜和脱石蜡存档肝脏标本。程序——通过原子吸收火焰光谱法分析新鲜冷冻肝脏标本（通过模拟针芯活检和楔形活检获得）、新鲜肝组织和脱石蜡存档标本（0.5至14年）中的铜、铁和锌浓度。根据组织金属浓度分配临床严重程度评分。结果——金属标准品的批间变异<4%。连续8天对肝脏组织的测量产生了较高的变异系数（3.6%至50%），反映了组织学金属分布的异质性；肝脏1和脱石蜡存档组织中的变异最高。组织学评估证实了金属分布的异质性。楔形活检标本中检测到的金属浓度范围最大。在金属浓度高的组织中，针芯活检标本中的铜和铁浓度明显低于楔形活检标本。脱石蜡存档标本中较高的锌浓度掩盖了20只犬中10只（50%）新鲜肝脏组织中的低锌浓度。结论及临床意义——对脱石蜡存档肝脏标本中铜和铁浓度而非锌浓度的回顾性测量提供了相关信息。针芯活检标本用于测量金属浓度的价值值得怀疑。
