Immunochemical Studies on Carcinoembryonic Antigen: (1) Quantitative Determination in Carcinomatous and Noncarcinomatous Tissues

Anti-CEA serum was prepared by immunizing rabbits with a crudeCEA fraction obtained from perchloric acid soluble extractsof adenocarcinoma of the stomach. After absorption, the antiserumproved to be monospecific for CEA. With Mancini's technique,CEA concentrations in perchloric acid extracts of carcinomatousand noncarcinomatous tissues were quantitatively determinedand expressed in terms of unit/ml, equivalent to mg/ml proteinconcentration of standard CEA solution. Finally, ratios of CEAunits per mg protein (CEA/P) of tissue extract were calculated. The CEA/P ratios tended to be higher in extracts from colonic,rectal and pancreatic carcinomas than in those from gastriccarcinoma, whereas they were lower in those from primary hepatomaand lung cancer. In the same patients with cancer, the ratiosfor carcinoma tissues were remarkably higher than those forthe noncarcinomatous counterparts. However, the ratios werenot related to the histological types of cancers. Relativelyhigh ratios were also observed in diseased intestinal mucosaof colonic polyposis and Crohn's disease, as well as in partsof gastric mucosa with a marked intestinal metaplasia obtainedfrom a cancerous stomach. More studies will be required to evaluatethe significance of occurrence in precancerous changes in tissues.     

MORPHOMETRY FOR MICROVESSELS IN EARLY GASTRIC CANCER BY NARROW BAND IMAGING‐EQUIPPED MAGNIFYING ENDOSCOPY

Background and Aim: Microvascular architecture is a variable characterizing early gastric cancer (EGC) against the background. The aims of the present study were to measure morphological variables of the microvessels and to compare the variables between EGC and the background. Methods: Narrow band imaging (NBI)‐equipped magnifying endoscopic pictures from 32 patients with EGC were used. The endoscopic pictures were taken under maximal magnification and processed for the microvessels in an in‐focus area after correction of image distortion. The segmented microvessels were numbered for microvessel density (counts/mm²) and vascular bed area (% ratio of vascular bed against the region of interest). The microvessels were further processed for a set of skeletonized pixels to count the characteristic points, including end‐points, crossing points, branching points and connecting points. Results: Microvessels in cancer were found to have a significantly larger connected point number (20.5 ± 6.1, P = 0.0002) than those in the background (17.4 ± 3.9). Numbers of the end‐points and branching points were found to be significantly larger in cancer than in the background (end‐points 3.6 ± 0.7 for cancer vs 3.3 ± 0.4 for background, P = 0.0005; branching points 0.8 ± 0.4 for cancer vs 0.7 ± 0.2 for background, P = 0.0014). However, microvessel density, vascular bed area and mean diameter did not significantly differ between cancer and the background. Conclusion: This finding can be considered to reflect the reported observation of an irregular vascular pattern in gastric cancer. This method may provide a means for microvessel morphometry, regardless of the organ studied.     

Scavenger receptors that recognize advanced glycation end products

Scavenger receptors recognize modified low-density lipoproteins (LDLs) such as acetylated LDL and oxidized LDL. Advanced glycation end products (AGE), which are generated through long-term exposure of proteins to glucose, also behave as active ligands for some scavenger receptors, including class A scavenger receptor (SR-A) and class B scavenger receptors such as CD36 and scavenger receptor, class B, type I (SR-BI). SR-BI, the first identified high-density lipoprotein (HDL) receptor, plays key roles in reverse cholesterol transport by promoting selective uptake of cholesteryl esters (CE) in HDL by hepatocytes, and cholesterol efflux of unesterified cholesterol from peripheral cells to HDL. Using Chinese hamster ovary cells overexpressing SR-BI (CHO-SR-BI cells), it was demonstrated that AGE-bovine serum albumin binds to SR-BI and inhibits selective uptake of HDL-CE by CHO-SR-BI cells as well as cholesterol efflux from CHO-SR-BI cells to HDL, suggesting potential roles of AGE in diabetic dyslipidemia and accelerated atherosclerosis in diabetes.