Thymic Structures Containing Somatostatin.

Double immunofluorescent staining confirmed co-expression of somatostatin (neuropeptide) and antigen-presenting cells of macrophage origin expressing major histocompatibility complex class II molecules in the intact thymus. The results confirmed cooperation of the neuropeptide and immunocompetent systems.

Morphofunctional adaptation of rat thymus structures to silicon consumption with drinking water.

Administration of standardized drinking water containing 10 mg/liter silicon for 2 months adlibitum induced structural reorganization of the cortical and medullary layers of the thymiclobules in laboratory rats accompanied by functional activation of monocyte/macrophage cells and antigen-presenting cells was changed in morphological structures of the thymus. A possible mechanism of development of autoimmune processes under the effect of silicon is discussed.

Effect of orchiectomy on structures of the thymus expressing major histocompatibility complex class II molecules.

Morphological and immunohistochemical study was performed to evaluate the effect of orchiectomy on structures of the thymus expressing major histocompatibility complex class II (MHC-II) proteins. Male sex hormone deficiency in the organism led to an increase in the number of MHC-II+ cells in the medulla and cortex of the thymic lobule. At the same time, the count of these cells in the corticomedullary zone decreased after orchiectomy. These changes modify homeostasis and activate immune processes.

A long-term coculture model for the study of mast cell-keratinocyte interactions.

Physiologic and pathologic events associated with cutaneous differentiation and repair are the result of a concerted action of various types of resident tissue cells. In vitro models simulating this complex in vivo situation are therefore needed to clarify the specific contribution and relevant interaction of, for example, dermal mast cells with other major cutaneous cells. The aim of this study was to establish a long-term coculture model that includes dermal mast cells, dermal fibroblasts, and keratinocytes in a human skin equivalent organotypic setting. Normal dermal mast cells and fibroblasts (1:4) were enclosed in collagen gel and normal keratinocytes were grown on top with exposure to the air interface. Under these conditions, mast cell integrity and functionality was preserved even after 4 wk of culture, as shown by electron microscopy and immunohistochemistry using antibodies against the mast-cell-specific granule enzyme tryptase and the receptors for stem cell factor and IgE. Mast cells also released histamine on stimulation with anti-IgE, and on ultrastructure were found to degranulate, with decrease of granule matrix density and formation of cell-cell contacts with fibroblasts. After 2 wk of culture, keratinocytes had formed an epidermis-like multilayer and were able to proliferate and differentiate, as shown by bromodeoxyuridine incorporation of basal cells and immunohistochemical staining for transglutaminase and cytokeratins 1 and 10. The model presented here thus provides a potentially relevant tool to further clarify the interaction of dermal mast cells with major other skin cells and their contribution to cutaneous physiology, repair processes, and pathology.

Chronic porcine two-hit model with hemorrhagic shock and Pseudomonas aeruginosa sepsis.

BACKGROUND: Sepsis is still a major cause of death despite well-developed therapeutical strategies such as antibiotics and supportive medication. The aim of this study was to characterize the long-term effects of a two-hit porcine sepsis model with a hemorrhagic shock as 'first hit' followed by a Pseudomonas aeruginosa infusion as 'second hit'. MATERIALS AND METHODS: Twelve juvenile healthy pigs were anesthetized and hemodynamically monitored. The two-hit group (n = 6) underwent a hemorrhagic shock with a 50% reduction of the mean arterial pressure and/or cardiac index for 45 min, followed by resuscitation, while the control group (n = 6) received no pretreatment. All chronically catheterized conscious pigs were challenged with a P. aeruginosa infusion (1.6 x 10(7) CFU/kg/h for the first 24 h followed by 1.6 x 10(6) CFU/kg/h for the next 24 h) and observed for another 48 h. RESULTS: The two-hit group showed the following significant differences to the control group: higher APACHE II scores prior to sepsis induction, increased persisting mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance index (PVRI) during bacterial challenge. In contrast, systemic vascular resistance (SVRI) was reduced at the end of the study. Throughout the observation period, the mean arterial pressure (MAP) was significantly reduced. CONCLUSIONS: The present study shows that the clinical course and hemodynamic effects of a P. aeruginosa sepsis will be aggravated by a preceding hemorrhagic shock during an observation period of 96 h. This two-hit model represents a valid, clinically relevant experimental protocol in sepsis research.

Fluorescent granular cells of the thymus can be identified as dendritic macrophages.

Fluorescent granular cells of the thymus lobule containing neurotransmitter monoamines express Ia antigen and S-100 protein, which attests to their macrophage origin; positive staining with aldehyde fuchsin points to secretion of peptide hormones by these cells. These facts and the absence of phagocytic activity allow to identify these cells as dendritic macrophages.

Neurotransmitter bioamine supply of thymic and lymph node structures during treatment with somatotropic hormone.

The effects of somatotropic hormone on bioamine-containing structures of immunocompetent organs in rats were studied after 1, 3, 7, and 14 days of treatment by fluorescent histochemical methods and microspectrofluorometry. The effect of somatotropic hormone on immune processes can be mediated by changes in the neurotransmitter content in the thymus and lymph nodes.