Anatomy, immunohistochemistry, and numerical distribution of human splenic microvessels

The microvascular architecture of the spleen plays an important role in the immunological function of this organ. The different types of vessels are related to different reticular cells each with their own immunomodulatory functions. The present study describes an immunohistochemical and morphometric analysis of the various types of vessels in 21 human autopsy non-pathological splenic samples. On an area of 785,656.37 μm² for each sample, we classified and quantified the type and number of vascular structures, each according to their morphology and immunohistochemical profile, and obtained the ratios between them. The distribution of trabecular vessels and the characteristics of the venules are reviewed. In our material the so-called "cavernous perimarginal sinus" (anatomical structure previously described by Schmidt et al., 1988) was observed and interpreted as a curvilinear venule shaped by the follicle in contact with the trabecular vein. Our material comprised 261 trabeculae (containing 269 arterial sections and 508 venous sections), 30,621 CD34+ capillaries, 7739 CD271+ sheathed capillaries, 2588 CD169+ sheathed capillaries, and 31,124 CD8+ sinusoids. The total area (TA) (14,765,714.88 μm²) occupied by the sinusoidal sections of the 21 cases was much higher than the TA of the capillary sections (1,700,269.83 μm²). Similarly, the TA (651,985 μm²) occupied by the sections of the trabecular veins was much higher than the TA of the trabecular arteries (88,594 μm²). The total number of CD34+ capillaries and of sinusoids CD8+ was similar for the sum of the 21 cases, nevertheless there were large differences in each case. Statistically the hypothesis that the number of capillaries and sinusoids are present with the same frequency is discarded. In view of the absence of a numerical correlation between capillaries and sinusoids, we postulate that very possibly the arterial and the venous vascular trees are two anatomically independent structures separated by the splenic cords. We believe that this is the first work where splenic microvascularization is simultaneously approached from a morphometric and immunohistochemical point of view.

Immunocytochemical typification of mesothelial cells in effusions: in vivo and in vitro models

We have performed immunocytochemical, immunoelectron microscopy, Western blot, and culture techniques using monoclonal antibodies against cytokeratin, vimentin, and desmin on 17 benign and 20 malignant effusions of pleural and ascitic origin. Triple coexpression of these three antigens was observed in benign reactive mesothelial cells as well as in one case of mesothelioma. All metastatic adenocarcinoma cells were consistently negative to desmin and positive to cytokeratin and vimentin. Present results were helpful to distinguish reactive and malignant mesothelioma from metastatic carcinoma cells in effusions.

Immunohistochemical characterization of 130 cases of primary hepatic carcinomas

Primary liver carcinoma (PLC) may express a certain number of markers. Here we communicate results of an analysis of five such markers (alpha-1-antitrypsin--AAT--, carcino-embryonic antigen --CEA--, alpha-fetoprotein --AFP--, and superficial --HBsAg-- and core --HBcAg-- antigens of hepatitis B virus) by means of PAP techniques in 130 cases of PLC, comparing the neoplastic tissue and the non-tumorous liver. Three variants of PLC are distinguished: hepatocarcinoma (HC) (108 cases); cholangiocarcinoma (CC) (19 cases); and three cases of hepatocholangiocarcinoma (HCC). AAT was positive in 29 HC, 2 HCC, and negative in all 19 CC. CEA appeared positive in 16 HC, 16 CC and only one HCC. AFP was positive in two HC, and negative in all CC and HCC. HBsAg displayed positivity in 15 HC and one HCC, being negative in all 19 CC. HBcAg was positive in 4 HC, and negative in all CC and HCC. HBsAg was also positive in two neoplastic emboli associated with HC. On the non-tumorous liver tissue the immunohistochemical results showed positivity for AAT and CEA, but not for AFP. Therefore the present results confirm that in the geographical area from which these tumors proceed, PLC is closely correlated with HBsAg positivity and with cirrhosis.