Cytoplasmic steroid receptors in tumoral and "normal" endometrial samples from symmetrical uterine zones.

Cytosol progesterone (PgR) and estradiol (E2R) receptors were quantified simultaneously in "normal" and tumoral endometrium samples, located symmetrically on the longitudinal axis of the uterine cavity. With this experimental model two different groups of patients were detected. In the first group (7 of 10 women), the endometrial carcinoma had a greater cytosolic concentration of PgR than the corresponding "normal" endometrium, both kinds of tissue being affected by the same circulating hormonal "environment," peculiar to each patient. The opposite occurs in the other group (3 of 10 women), since the "normal" endometrium was found to be "richer" in receptors than the tumoral endometrium. It is suggested that this difference in the capacity of the tumor for synthesizing PgR and even E2R as compared to the "normal" endometrium may be a marker which improves selection of patients who will be more likely to respond favorably to endocrine therapy.

Association of microneme antigens of Plasmodium brasilianum merozoites with knobs and other parasite-induced structures in host erythrocytes.

The localization of Plasmodium brasilianum antigens, common to merozoite micronemes and parasite-induced structures in the host erythrocyte, was determined by means of immunogold electron microscopy and monoclonal antibodies directed against blood stages of this parasite. All monoclonal antibodies reacted with micronemes. In addition, some reacted with either knob protrusions or caveolae of the host erythrocyte membrane; one reacted with a parasite-derived antigen present in the erythrocyte cytoplasm. Gold particles appeared over the membranes of ring-infected cells before the appearance of knobs and caveolae. We hypothesize that at least some knob- and caveolae-associated antigens of P. brasilianum are inserted into the erythrocyte membrane at the time of merozoite invasion.

Leishmania braziliensis: localization of glycoproteins in promastigotes.

Two species of glycoproteins from Leishmania braziliensis promastigotes of apparent molecular weights of 53,000 (glycoprotein 53) and 47,000 (glycoprotein 47) were localized. Four lectins with different sugar specificities bound to the blotting sheet to which the electrophoretically separated materials were transferred. Concanavalin A and Ricinus communis agglutinin bound to the band of glycoprotein 53 and the lectin from Dolichos biflorus bound to the band of glycoprotein 47. Wheat germ agglutinin bound to the bands of both glycoproteins. Histochemical examinations using fluorescence labeled lectins demonstrated that the glycoproteins 53 and 47 were located on the cell surface and in the cytoplasm of promastigotes, respectively. The results are consistent with the result of agglutination test.

Application of current chemical concepts to metal-hematein and -brazilein stains.

Current chemical concepts were applied to Weigert's, M. Heidenhain's and Verhoeff's iron hemateins, Mayer's acid hemalum stain and the corresponding brazilein compounds. Fe bonds tightly to oxygen in preference to nitrogen and is unlikely to react with lysyl and arginyl groups of proteins. Binding of unoxidized hematoxylin by various substrates has long been known to professional dyers and was ascribed to hydrogen bonding. Chemical data on the uptake of phenols support this theory. Molecular models indicate a nonplanar configuration of hematoxylin and brazilin. The traditional quinonoid formula of hematein and brazilein was revised. During chelate formation each of the two oxy- groups of the dye shares an electron pair with the metal and contributes a negative charge to the chelate. Consequently, the blue or black 2:1 (dye:metal) complexes are anionic. Olation of such chelates affects the staining properties of iron hematein solutions. The color changes upon oxidation of hematoxylin, reaction of hematein with metals, and during exposure of chelates to acids can be explained by molecular orbital theory. Without differentiation or acid in dye chelate solutions, staining patterns are a function of the metal. Reactions of acidified solutions are determined by the affinities of the dye ligands. Brazilein is much more acid-sensitive than hematein. This difference can be ascribed to the lack of a second free phenolic -OH group in brazilein, i.e. one hydrogen bond is insufficient to anchor the dye to tissues. Since hematein and brazilein are identical in all other respects, their differences in affinity cannot be explained by van der Waals, electrostatic, hydrophobic or other forces.

The proteins of the cytoplasmic ribosomes of Euglena gracilis.

Two types of cytoplasmic ribosomes of Euglena gracilis have been found when the stability in vitro of the large subunit at 25 degrees C for 30 min has been considered. Sucrose density gradient analysis have revealed that the large subunit of ribosomes obtained from cells harvested in the stationary phase of growth was degraded when heated at 25 degrees C. The large subunit of ribosomes obtained from exponentially growing cells was stable in the same experimental conditions. Studies of the ribosomal RNAs have not explained this differential stability observed in vitro. In fact, after SDS-extraction, the largest RNA species always appears degraded in both types of ribosomes. Therefore, an explanation to this phenomenon have been searched for through the analysis of the ribosomal proteins. One and two dimensional gel electrophoresis techniques have been employed. At least one difference between the two ribosomal protein groups has been observed and this could be associated to the differential stability of the ribosomes. Approximately 72 proteins molecules have been found in Euglena's cytoplasmic ribosome. About 42 proteins belong to the large subunit and 30 to the small one.

[Endotoxins and liver]. / Endotoxinas e hígado.

Endotoxins are macromolecules containing lipopolysacharides that form part of the bacteria wall. They are released only when the cell integrity is lost. They are suceptible to be absorved and pass to the portal circulation. However, in normal individuals endotoxins are not detected in peripheral blood, due to a filter effect of the liver. The possibility that liver failure could produce alterations in the detoxification of endotoxins is analyzed as well as the role of endotoxins to initiate or perpetuate liver damage. The biological effects of endotoxins on bile secretion, liver circulation, energy and carbohydrate metabolism in the liver are described.