Intestinal lymphoid tissue changes in the cortisone-treated Wistar rat.

This paper continues the previous investigation of the Department on the lymphoid tissue of central and peripheral lymphoid organs under different experimental conditions. The morphological reactional modalities of the intestinal lymphoid tissue in the male Wistar rat were followed up under endocrine imbalance conditions following cortisone administration. Seven days after administration cortisone induced a hyperplasia of the intestinal lymphoid tissue in parallel with a depletion of the lymph node parenchyma and a hypercellularity of bone marrow. After a 6-week postcortisone interval, the lymphoid tissue showed changes corresponding to a cellular depletion in parallel with the restoration of the lymph node parenchyma and a normocellular bone marrow.

Postovariectomy bone marrow changes in irradiated and unirradiated wistar rats.

Bilateral ovariectomy of Wistar rats has per se a stimulative effect on the myeloid tissue, determining a hypercellularity of this organ-tissue. On the other hand, under the conditions of a whole-body irradiation with a single dose of 800 r X-rays, bilateral ovariectomy manifests a protective effect on the myeloid tissue preventing the development of hypoplastic, respectively aplastic modifications.

Postcortisone medullary changes in the irradiated and unirradiated male Wistar rat.

Cortisone administration in male Wistar rat induces a depletion of the granulocytic-normoblastic cell population in the bone marrow in parallel with a numerical increase by accumulation of lymphoid and undifferentiated cells. These changes are more intense under irradiation conditions. The reversibility of medullary modifications is shown by the integrity of the reticulinic skeleton of the bone marrow.

Histological and histochemical study of rat salivary glands during their postnatal development.

The postnatal development of the three major salivary glands (parotid, submaxillary and sublingual) was comparatively followed up from the histological viewpoint and in relation with some histochemical reactions. The sublingual gland presented a well developed cytomorphological structure at birth, whereas the parotid and the submaxillary ones, immature at birth, gradually reached the overall appearance of adult glands, the former at 5--6 weeks, the latter at 8 weeks. In relation with the product secreted, it is already from birth that the parotid and the submaxillary glands presented negative reactions for mucosubstances and positive ones for revealing the protein-bound groups. The sublingual gland exhibited from the first postnatal 24 hrs positive reactions for revealing mucosubstances at the level of glandular secretory glands.

Effects of the "reverse" administration of sexual hormones on the lymph node structure in irradiated Wistar rats.

The whole-body irradiation of adult Wistar rats with a single dose of 800 r X-rays intensifies the lymph node changes and the decrease of the colloidopexic capacity of hepatosplenic macrophages established by the "reverse" administration of sexual hormones. The modifications observed after estradiol administration to the male rat are more marked after a 6 months' interval than those caused in the same interval by testosterone in the female rat lymph nodes.

Spleen and lymph node changes in rats irradiated with X-rays and treated with testosterone.

The authors have studied the effect of testosterone administration in male adult Wistar rats irradiated with a single total dose of 800 r X-rays. The results obtained show that testosterone exerts a double radioprotective action. This hormone prevents both the occurrence of the senile type spleen and lymph node changes and the depression of the colloidopexic capacity of the hepatosplenic macrophages. At the same time, these results suggest that testosterone induces hyperplasia of the lymphocytic elements, particularly of T lymphocytes.

Spleen and lymph node reticulofibrosis in "chemically thyroidectomized" rats.

The effects of the X-rays on the peripherial lymphoid organs (lymph nodes and spleen) in male adult wistar rats "chemically thyroidectomized" (methylthiouracil) have been studied. Spontaneous death of these animals 9 days after the irradiation was determined by the hypoplasia (aplasia) of the hematogenous bone marrow. The spleen and lymph node changes -- represented by the lymphoid tissue depletion and reticulofibrosis -- in the experimental animals were similar to those observed in animals sacrificed 6-8 months after irradiation. They differed from the latter by the absence of the macromolecular hyperstability of the reticular and collagenous fibers, which is proper to early ageing by X-rays.