Histidine decarboxylase and urinary methylimidazoleacetic acid in gastric neuroendocrine cells and tumours

AIM: To study histidine decarboxylase(HDC) expression in normal and neoplastic gastric neuroendocrine cells in relationship to the main histamine metabolite. METHODS: Control tissues from fundus(n = 3) and corpus(n = 3) mucosa of six patients undergoing operations for gastric adenocarcinoma, biopsy and/or gastric surgical specimens from 64 patients with primary gastric neuroendocrine tumours(GNETs), as well as metastases from 22 of these patients, were investigated using conventional immunohistochemistry and double immunofluorescence with commercial antibodies vs vesicular monoamine transporter 2(VMAT-2), HDC and ghrelin. The urinary excretion of the main histamine metabolite methylimidazoleacetic acid(U-Me Im AA) was determined using highperformance liquid chromatography in 27 of the 64 patients.RESULTS: In the gastric mucosa of the control tissues, co-localization studies identified neuroendocrine cells that showed immunoreactivity only to VMAT-2 and others with reactivity only to HDC. A third cellpopulation co-expressed both antigens. There was no co-expression of HDC and ghrelin. Similar results were obtained in the foci of neuroendocrine cell hyperplasia associated with chronic atrophic gastritis type A and also in the tumours. The relative incidence of the three aforementioned markers varied in the tumours that were examined using conventional immunohistochemistry. All of these GNETs revealed both VMAT-2 and HDC immunoreactivity, and their metastases showed an immunohistochemical pattern and frequency similar to that of their primary tumours. In four patients, increased U-Me Im AA excretion was detected, but only two of the patients exhibited related endocrine symptoms. CONCLUSION: Human enterochromaffin-like cells appear to partially co-express VMAT-2 and HDC. Coexpression of VMAT-2 and HDC might be required for increased histamine production in patients with GNETs.

人骨折骨痂中转化生长因子β_1的免疫组化研究

为了解转化生长因子β１（ＴＧＦ－β１）在人骨折骨痂中的细胞定位，表达强度及其与骨折修复的关系，采用不同修复阶段的人骨折骨痂组织切片，以ＴＧＦ－β１抗体进行免疫组化研究。结果发现：成骨细胞、新骨骨基质、修复中的关节软骨细胞中ＴＧＦ－β１染色强阳性，肥大的软骨细胞染色阴性。改建期骨破骨细胞染色阳性。染色强度在１４～２６２天中逐渐减弱。骨不连组织ＴＧＦ－β１染色阴性。ＴＧＦ－β１可能由人成骨细胞合成并分泌入基质，并自骨折后的较早期直至改建期持续发挥重要作用。

肾上腺及其病变组织中内皮素－1的免疫组织化学和超微结构观察

观察、研究内皮素－１（ＥＴ－１）在人肾上腺及其病变组织中的形态学定位。方法用免疫组织化学的方法研究了ＥＴ－１在肾上腺瘤性和非瘤性组织中的组织学情况和电镜定位。结果ＥＴ－１免疫阳性物质存在于肾上腺皮质腺瘤（１００％）、皮质腺癌（３／１０）和瘤旁组织（１００％）中，而不存在于髓质组织中。ＥＴ－１免疫阳性物质以环状和颗粒状存在于肾上腺皮质腺瘤、皮质增生组织和瘤旁组织细胞胞浆内和胞膜上，以粉尘状存在于肾上腺癌个别细胞胞浆内。免疫电镜下ＥＴ－１阳性物质存在于粗面内质网、线粒体、脂质体和细胞膜上。结论提示ＥＴ－１与肿瘤分化程度有关，ＥＴ－１免疫组织化学染色，可能具有鉴别肾上腺良恶性皮质腺瘤的意义；ＥＴ－１阳性物质存在于粗面内质网，说明ＥＴ－１是由皮质细胞合成的；存在于线粒体和脂质体，说明ＥＴ－１与皮质激素合成有关；存在于细胞膜上可能与ＥＴ－１受体有关。