Increased leucocyte histamine release by Entamoeba histolytica antigen in patients with amoebic abscess of the liver.

Leucocytes (basophils) from non-atopic adult subjects living in an area highly endemic with Entamoeba histolytica release histamine in a dose-dependent fashion upon in vitro exposure to an antigen of axenically grown E. histolytica (histolyticin). Leucocytes of patients with acute amoebic liver abscess were significantly more sensitive to this antigen than leucocytes of control subjects, including patients that had recovered from amoebic liver abscess. By comparison Concanavalin-A induced histamine release found in patients with amoebic liver abscess and healthy controls suggest an immunological mechanism for histolyticin induced in vitro histamine release. This is also suggested by the inability of histolyticin to release histamine from leucocytes of healthy newborn infants and the significant fall in sensitivity to histolyticin following incubation of leucocytes in acid pH. Histamine and other mediators may contribute locally to the early intense inflammatory reaction observed in tissue invasion by E. histolytica.

Liberacion in vitro de histamina leucocitaria provocada por antigeno amibiano y por concanavalina en pacientes con amibiasis invasora. / In vitro liberation of leukocyte histamine induced by an amebic antigen and by concanavalin in patients with invasive amebiasis

Se estudio la liberacion de histamina leucocitaria en pacientes con absceso hepatico amibiano agudo, absceso curado, condiciones agudas no amibianas y testigos sanos, utilizando un antigeno amibiano (histoliticina) y un liberador inespecifico (concanavalina A).La liberacion de histamina en leucocitos de pacientes con absceso hepatico amibiano agudo requirio de cantidades significativamente menores de histoliticina que en los leucocitos de los otros tres grupos estudiados, empero no fue diferente utilizando concanavalina A.Se sugiere un estado de hipersensibilidad inmediata a la histoliticina com probable explicacion de este fenomeno en los pacientes con absceso hepatico amibiano agudo. La histamina asi liberada podria contribuir a modular la inflamacion temprana y tardia en la amibiasis invasora

Fluorometric detection of implantation sites in rats.

A new fluorescent technique is proposed for detecting implantation sites in the rat, based on the binding capacity of tetracycline. Both intraluminal (20 microgram/kg) and intravenous (8.3 mg/kg) administrations of tetracycline permit the macroscopic visualization (under 366 nm of ultraviolet light) of implantation sites, since they show a lower fluorescence (LFS) than the remaining endometrium (FS). Greater binding of tritiated tetracycline was observed in nonimplantation sites (176 to 56 x 10(3) dpm/mg protein) than in implantation sites (P < 0.05).

High resolution cytochemical study of uterine epithelial cell surface of the rat at identified sites previous to blastocyst-endometrial contract.

A transmission electron microscopy study was carried out in prospective implantation sites in uterine horns of rats of the Long Evans strain. The purpose was to search for possible modifications in glycoproteins of outer coats of endometrial epithelium shortly before blastocyst-endometrial contact Shea's technique (Lanthanum-Alcian blue) was used to visualize glycoproteins. Prospective implantation sites disclosed a rather thin finely granular electrondense layer along the plasma membrane of the surface endometrial cells. In addition, there was a decrease in the number of microvilli as well as a lack of Lanthanum precipitate in junctional complexes. Sites remote from prospective implantation areas, disclosed a thicker electrondense layer of glycoproteins in cell plasma membranes including those of well developed microvilli. The junctional complexes were well depicted by the electrodense lanthanum salt precipitates. These observations suggest that a mechanism other than a more physical contact take place and induce the above changes.

[New concepts related to implantation. III. Biochemical characteristics]. / Nuevos conceptos relacionados con la implantación III. Características bioquímicas.

The fixed position of trophoblast in the uterus is preceded by zygote orientation and its contact, adhession and fusion with endometrial cell membrane. These interactions take place in a precise site called "implantation site". The identification of this area by the administration of pontamine blue has allowed biochemical studies which showed an increase (in the site) of glycolytic enzymes activity of the pentose cycle, of beta-glucuramidase and of acid and alkaline phosphatase; with a decrease in catepsine D activity. In non implanted tissue, isocitric dehydrogenase activity is decreased. From the biochemical standpoint the implanted endometrium may be different from the rest, which allows a better knowledge of possible molecular mechanisms related with implantation, as well as the possible inhibition with medication.