Valente P T, Hoober J K, Phillips S J
Department of Pathology, Temple University Health Sciences Center, Philadelphia, Pennsylvania 19140.
Ultrastruct Pathol. 1988 Nov-Dec;12(6):613-20. doi: 10.3109/01913128809056486.
The rare tyrosine-rich crystalloids (TRC) of salivary gland pleomorphic adenoma (PA) give a positive Million reaction indicating the presence of tyrosine. Their varied histochemical reactions, however, suggest a more complex composition. Two cases of TRC were encountered in a series of 144 PA (1.4%). Both were studied with several histochemical stains, and one tumor particularly rich in TRC was further examined with transmission and scanning electron microscopy and subjected to biochemical analysis using fresh-frozen tissue. TEM showed amorphous, electron-dense masses with no discernable internal structure. SEM revealed a geodelike structure of radially arranged, interlocking plates. Amino acid analysis of normal parotid, tumor with TRC, and a similar tumor without TRC indicated a slightly elevated level of tyrosine and arginine in the tumor with TRC. Polyacrylamide gel electrophoresis of tissue dissolved in sodium dodecyl sulfate revealed dense banding corresponding to polypeptides of a relative molecular weight of approximately 17,000 only in the TRC-rich sample. These bands on further analysis contained relatively large amounts of arginine. Tyrosine was present in only small amounts. TRC appear to be small proteins containing some tyrosine but rich in arginine.
涎腺多形性腺瘤（PA）中罕见的富含酪氨酸的晶体（TRC）呈阳性米隆反应，表明存在酪氨酸。然而，它们多样的组织化学反应提示其成分更为复杂。在144例PA中发现了2例TRC（1.4%）。对这2例均进行了多种组织化学染色研究，对其中1例TRC特别丰富的肿瘤进一步进行了透射电子显微镜和扫描电子显微镜检查，并使用新鲜冷冻组织进行了生化分析。透射电子显微镜显示为无定形、电子致密的团块，无明显内部结构。扫描电子显微镜显示为呈放射状排列、相互连锁的板层构成的似晶洞样结构。对正常腮腺、含TRC的肿瘤以及不含TRC的类似肿瘤进行氨基酸分析表明，含TRC的肿瘤中酪氨酸和精氨酸水平略有升高。对溶解于十二烷基硫酸钠中的组织进行聚丙烯酰胺凝胶电泳显示，仅在富含TRC的样本中出现了与相对分子质量约为17,000的多肽相对应的致密条带。进一步分析这些条带发现含有相对大量的精氨酸。酪氨酸仅少量存在。TRC似乎是含有一些酪氨酸但富含精氨酸的小蛋白质。
