Bauhinia purpurea agglutinin (BPA) binding sites in human gastrointestinal tract.

The binding of biotinylated BPA to parraffin sections of 18 normal gastrointestinal tract mucosa, 5 nonneoplastic polyps (NNP), 12 adenomas, and 59 carcinomas was studied by using avidinbiotin peroxidase complex (ABC) technique. In normal mucosa BPA appeared to bind both mucus and nonmucus glycoproteins but goblet cell mucus showed a decrease in binding and increase in binding of nonmucus glycoproteins as the cells lose their differentiation. BPA showed characteristic binding patterns in adenoma and carcinoma that differed from the pattern in normal mucosa. In normal mucosa linear binding to the apical cytoplasm in the columnar cells of the surface epithelium was observed, whereas in adenomas and carcinomas, in addition to the linear binding to the apical cytoplasm, diffuse cytoplasmic and granular deposits in the supranuclear, paranuclear or infranuclear zones were seen. Our findings suggest that BPA binding patterns in normal and neoplastic mucosa are related to the degree of cellular differentiation. In the process of malignant transformation the carbohydrate distribution undergoes progressive changes through the adenoma carcinoma sequence. These changes are related to the degree of dysplasia in adenomas and to the degree of differentiation in carcinomas.

Lectin receptors distribution in the surface membrane of Trypanosoma cruzi blood forms collected from mice submitted to specific treatment

The author investigated the distribution of lectin receptors on Trypanosoma cruzi blood forms collected from mice inoculated with, respectively, the drug-resistant and drug-sensitive strains VL-10 and CL, and treated with the two standard active nitroheterocyclic compounds nifurtimox and benznidazole used for treatment of human Chagas' disease. Blood trypomastigotes purified in Fycoll-Hypaque were incubated with fluorescein-labelled lectins Con A, WGA, EE, WFA, TPA and PNA and then microscopically examined. Neither qualitative or quantitative differences in the fluorescence intensity could be detected between parasites from VL-10 and CL strains submitted or not to treatment. The results suggest that both strains do not differ in their surface membrane carbohydrate moieties. Moreover, the rapid clearance of blood forms the drug-sensitive strain in animals treated with singlo doses of both compounds is not likely to depend on membrane alterations expressed by changes in the carbohydrate components. furthermore, resistance or sensitivity to drugs is not apparently related to carbohydrate distribution on T. cruzi blood forms