Combinatorial Effects of Organophosphate (Temephos), Glyphosate (Roundup) and Sodium Dodecil Sulfate (Sds) on Zebrafish (Danio Rerio) Gills: A Morphometric and Histological Study

Pesticides, as Temephos and Roundup, and surfactants, like Sodium Dodecyl Sulfate (SDS), when dicharged into the environment, are harmful to non-target wildlife, especially fish. To evaluate the effects of those chemicals alone and their binary combinations, we assessed the histological alterations in Danio rerio gills after 15 days of exposure to Temephos (1ppm), Roundup (10ppm), SDS (2ppm), SDS plus Temephos (2ppm+1ppm), SDS plus Roundup (2ppm+10ppm) and Temephos plus Roundup (1ppm+10ppm). Hyperplasia, a regressive change, was significant in all exposed groups. The progressive change, complete fusion of lamellae, was significantly intensive in Roundup plus Temephos group. Regarding to circulatory disturbances, vascular congestion was significant intensive in SDS group, while severe aneurysm was observed in Roundup group. Although xenobiotics in the blend are biologically complex, mainly for long periods, combinatorial exposure incremented only complete lamellar fusion. Our results reinforce the rationalization of indiscriminate use of those compounds alone or in combination.

STUDIES OF THE LYMPHATIC TISSUE

1. On subcutaneous infection of rabbits with staphylococci of low virulence there appears at the place of injection first a hemorrhagicpurulent inflammation and later a localized purulence. In the regional lymph nodes there is lymphatic hyperplasia, and in the blood a lymphocytosis. 2. In the regional lymph nodes there is first a regressive change of Flemming's secondary nodules and of transition forms. Then follows lymphatic hyperplasia, starting apparently from solid secondary nodules and progressing by way of pseudo-secondary nodules to a diffuse lymphoid hyperplasia. The increase of lymphocytes in the blood parallels this development. 3. Only after the highest point of the lymphocytosis has been reached or passed do we find the first Flemming's secondary nodules, which thereafter increase in number and size while the number of lymphocytes in the blood falls, and reach their maximum development when the number of lymphocytes in the blood is again normal. Therefore, the original conception of Flemming that the site of formation of the lymphocytes of the blood is in Flemming's secondary nodules, cannot be accepted. 4. The lymphocytes of the blood originate in the pseudo-secondary nodules as in embryonic life. The mother cells of the lymphocytes would appear to be Marchand's proliferating endothelial (reticular) cells.

BLOOD CELL FORMATION AND DISTRIBUTION IN RELATION TO THE MECHANISM OF THYROID-ACCELERATED METAMORPHOSIS IN THE LARVAL FROG

1. Thyroid-accelerated metamorphosis in the larval frog is accompanied by changes in the hemopoietic centers and in the blood cell distribution in the various regions of the body. These changes are interpreted as results of the fundamental change in basal metabolic rate induced by the thyroid treatment. 2. There is initiation of the shift of hemopoietic locus from the kidney, the larval hemopoietic organ, to the spleen, the adult hemopoietic organ. The spleen, being chiefly an erythrocyte producer, becomes of greater importance with the transition from the lower metabolic rate to the higher, since greater erythropoiesis becomes necessary to supply the physical basis for the maintenance of the higher metabolic rate. 3. It is suggested that the appearance of red bone marrow in the later history of the frog is correlated with a still higher metabolic rate. Phylogenetically, in the vertebrate series, red bone marrow is also associated with higher metabolic rate. 4. The new metabolic rate initiated in tadpoles by thyroid administration sets up a demand for (a) erythrocytes, (b) granulocytes and lymphoid phagocytes for distribution to regions of regressive change, (c) lymphocytes, (1) as progenitors of erythrocytes, granulocytes and phagocytes, (2) for promoting growth of cells in regions of progressive change. 5. Upon the hemopoietic reserve, which in the last analysis is the lymphocyte (and its mesenchymal precursor), depends the extent to which metamorphosis will proceed. Inability on the part of the hemopoietic centers, chiefly the spleen, to keep pace with the demand for blood cells during metamorphosis results in metamorphic stasis, a condition of anemia which is usually followed by death. 6. The growth-promoting function of leucocytes, as demonstrated by Carrel, is probably to be ascribed to the lymphocyte component of leucocytes. 7. The granulocytes have probably also a glandular function, and may exert a lytic effect upon adjacent tissues in regions of regressive change.