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The report deals with an investigation of the relationship between thymal cortical lymphocytes metabolism and antitumor response in Wistar rats with ovarian tumors, injected with Thio-TEPA intramuscularly and endolymphatically. Antitumor response and enzymatic indexes coordination appeared to be higher with the latter route.
We present a cervical thymic cyst clinically manifest as a lateral neck mass and studied preoperatively with ultrasound. We point to the sonographic findings that allow us to include the cervical thymic cyst as one of the diagnostic possibilities.
The microcirculation of thymic lobule has been studied. The vascular feature is markedly different compared with mammalian thymic circulation. Only one artery trunk, the intralobular thymic artery branching off from intralobular artery has been evidentiated. Interlobular arter penetrates the lobule and originates a bed of narrow thin-walled capilary network, thinner in the pheriphery.
Although X-ray microanalysis has become a well established technique in the study of tissues there are still relatively few papers reporting results from cells in culture. Our early investigations on freshly isolated murine thymocytes reported higher than expected concentrations of Na and Cl in these cells but subsequent studies have shown that these high concentrations are artefactual. Rat thymocytes that have been isolated and incubated for a short time to allow them to recover from the isolation procedure have lower concentrations of Na and Cl. Sections prepared from pellets of cells which have been concentrated by centrifugation in a microhaematocrit centrifuge have concentrations of Na and Cl which are within the range that has been described for thymocytes in tissues. This method of concentration can be applied successfully to the study of white cells from the peripheral blood. In diabetic animals pyknotic cells occur in the thymus. These cells are characterised by low concentrations of K but no rise in the concentration of Na. Study of thymocytes isolated from a diabetic animal also show pyknotic cells low in K confirming these observations.
There is evidence to indicate that the neuroendocrine and immune systems can interact. Thus, neuroendocrine hormones can modulate a variety of immune functions and there have been attempts to manipulate the neuroendocrine system of aged animals to enhance immune function. We have previously shown that the transplantation of a syngeneic pituitary gland under the kidney capsule of young adult mice elevates serum prolactin and enhances immune responsiveness. In the present study pituitary glands were transplanted under the kidney capsule of 22-month-old mice to determine if this maneuver can enhance a number of immunologic parameters. The results demonstrate that aged animals bearing transplanted pituitary grafts for 10 days did not exhibit any enhancement in their primary antibody response to sheep red blood cells, splenic T or B-cell mitogen responsiveness or restoration of thymic architecture. When these immunologic assessments are performed on animals bearing pituitary grafts for 28 days, the IgM and IgG primary antibody responses and splenic T-cell responsiveness are enhanced but repopulation of the thymus still does not occur. Importantly, this enhancement does not restore immunocompetence to levels observed in young mice.
Thirteen tumors of questionable genesis located in the thymus were studied. The microscopical structure of these tumors was identical to lymphogranulomatosis of other localization. Reactive proliferation of the thymic epithelium and cyst formation are characteristic of lymphogranulomatosis primarily developing in the thymus. The disease was not "granulomatous thymoma" since giant multinuclear cells by their structural characteristics corresponded to reticular elemens and the epithelial component was absent in extrathoracal formations.
At a histochemical investigation of the rabbit lymphoid organs innervation certain peculiarities on histotopography of adrenergic and acetylcholinesterase (AChE)-containing nervous elements have been established. At a chronic experiment by means of a dosed repeated bilateral electrostimulation of the posterior hypothalamic field in the organs mentioned, inhibition of the functional activity has been noticed. It is most specific not for the AChE-containing structures, but for the adrenergic ones, localized to some extent in the parenchyma, as well as along the course of the blood vessels and their adventitium. The results are discussed in terms of modulatory influence of the posterior hypothalamic field on trophic and functions of the lymphoid tissue. This influence is realized both humoraly and via the nervous pathways (either directly using certain ways and connections, or indirectly by means of neurogenic tonus of the intraorganic blood vessels regulation).
The pharmaceutical uses of cremophor EL, a non-ionic surfactant, are similar to those of polysorbate 80. In our previous study, polysorbate 80 exerted some adverse actions on rat thymocytes under in vitro condition. Therefore, the effects of cremophor EL on thymic lymphocytes were examined using a flow cytometer with appropriate fluorescent dyes. Cremophor EL at 10 microg/ml or more (up to 300 microg/ml) concentration-dependently decreased cellular content of glutathione. The cell viability of thymocytes under control condition was 95.4 +/- 1.2% (n = 7, mean +/- S.D.). The incubation of thymocytes with 300 microg/ml cremophor EL or 3 mM hydrogen peroxide for 2 h, respectively, decreased the cell viability to 90.8 +/- 2.8% or 91.2 +/- 2.6%. However, the simultaneous incubation with cremophor EL and hydrogen peroxide decreased the cell viability to 28.7 +/- 8.2%. Cremophor EL at 100 microg/ml accelerated the process of cell death induced by hydrogen peroxide. Results suggest that cremophor EL increases the susceptibility to oxidative stress. Cremophor EL at clinically relevant concentrations may increase the therapeutic potential of some anticancer agents to produce oxidative stress.
In the present study, the ultrastructure of the stromal components, basically epithelial elements and macrophages, of the thymus of adult natterjacks, Bufo calamita has been analyzed. A network of stellate epithelial-reticular cells joined together by desmosomes, constitutes the main component of the thymic parenchyma in both cortex and medulla. In the medulla pale, electron-lucent epithelial cells, sometimes showing surface interdigitations, are striking elements. Moreover, uni- and multicellular epithelial cysts appear in the thymic medulla as well as granulated cells of possible endocrine significance. Remarkably, isolated or grouped gland cells whose morphology and cytoplasmic content resemble that of the skin glands, were occasionally found. Finally, macrophages, multinucleated giant cells and dendritic-like cells, the latter intimately associated to lymphocytes, occur in the thymus of Bufo calamita. The most remarkable morphologic characteristics of all those non-lymphoid cell types, as well as their possible functional significance are comparatively discussed with available information on the amphibian and higher vertebrate thymic cytoarchitecture.
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Thymocytes are known to possess receptors for glucocorticoids (GC) as well as for alpha, 25-dihydroxyvitamin D3 [1,25-(OH)2D3]. We have now investigated the distribution of the receptors for GC and 1,25-(OH)2D3 in rat thymocytes and compared the effects of the two steroid hormones on short term primary cultures of these cells. We report that in thymic cells, as in other tissues, 1,25-(OH)2D3 and GC bind specifically to distinct receptor molecules which exhibit sedimentation coefficients of 3.3S and 3.7S, respectively. Furthermore, the thymocytes that express the 1,25-(OH)2D3 receptor belong to a different and distinct subpopulation than the cells that express the glucocorticoid receptor. Specifically, by separating the thymocytes into two subsets by means of agglutination with the lectin peanut agglutinin (PNA), we have determined that the 1,25-(OH)2D3 receptor-positive cells belong to the PNA-negative medullary mature subset, whereas the GC receptor-positive cells belong to the PNA-positive cortical immature subset of thymocytes. Finally, we have compared the effects of the two steroid hormones on primary cultures of each of the two subsets as well as on unseparated thymocytes and found that GC act on PNA-positive cells to induce cell lysis; this leads to an enrichment in 1,25-(OH)2D3 receptor-positive thymocytes, as indicated by an apparent increase (6-fold) in the 1,25-(OH)2D3 binding in the cells surviving at the end of the culture. In contrast, we found that 1,25-(OH)2D3 acts on the PNA-negative cells to decrease the rate of cell lysis. These data indicates that the target cells for GC and 1,25-(OH)2D3 in the thymus are distinct and that these two hormones exert a different regulatory influence on the gland.
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