Lipopolysaccharide induces tumor necrosis factor receptor-1 independent relocation of lymphocytes from the red pulp of the mouse spleen.

It is well known that bacterial lipopolysaccharide (LPS) induces migration of several cellular populations within the spleen. However, there are no data about the impact of LPS on B and T lymphocytes present in the red pulp. Therefore, we used an experimental model in which we tested the effects of intravenously injected LPS on the molecular, cellular and structural changes of the spleen, with special reference to the red pulp lymphocytes.

Suppression of methionine-induced colon injury of young rats by cysteine and N-acetyl-L-cysteine.

Changes in the methionine metabolism can cause a state called hyperhomocysteinemia, inducing oxidative stress in the gut. The production of free radicals is important in the colon damage caused by methionine. This study aimed at evaluating the effect of the use of L-cysteine and N-acetyl-L-cysteine on the colon morphometry of young rats treated with methionine.

Remodeling of extracellular matrix of the lamina propria in the uninvolved human rectal mucosa 10 and 20 cm away from the malignant tumor.

In recent years, it has been demonstrated that malignancy arises and advances through the molecular interplay between tumor cells and non-malignant elements of the tumor stroma, that is, fibroblasts and extracellular matrix. However, in contrast to the mounting evidence about the role of tumor stroma in the genesis and progression of the malignant disease, there are very few data regarding the uninvolved stromal tissue in the remote surrounding of the tumor. Using the objective morphometric approach in patients with adenocarcinoma, we demonstrate the remodeling of extracellular matrix of the lamina propria in the uninvolved rectal mucosa 10 and 20 cm away from the neoplasm.

Growth of Murine Splenic Tissue Is Suppressed by Lymphotoxin β-Receptor Signaling (LTβR) Originating from Splenic and Non-Splenic Tissues.

Development and maintenance of secondary lymphoid organs such as lymph nodes and spleen essentially depend on lymphotoxin β-receptor (LTβR) signaling. It is unclear, however, by which molecular mechanism their size is limited. Here, we investigate whether the LTβR pathway is also growth suppressing.

The role of microfibrillar-associated protein 4 (MFAP4) in the formation and function of splenic compartments during embryonic and adult life.

Microfibrillar-associated protein 4 (MFAP4) is an extracellular protein belonging to the fibrinogen-related protein superfamily and is recognized as an integrin ligand with suggested functions in pulmonary and vascular tissue homeostasis. MFAP4 expression in the spleen is increased during infections; however, the significance of MFAP4 for the function of the spleen is unknown. Immunohistochemistry, morphometry and real-time RT-PCR were used to analyze wild-type and MFAP4-deficient spleens.

Aberrant tissue positioning of metallophilic macrophages in the thymus of XCL1-deficient mice.

Metallophilic macrophages hold a strategic position within the thymic tissue and play a considerable function in thymic physiology. The development and positioning of these cells within thymic tissue are regulated by complex molecular mechanisms involving different cytokine/chemokine axes. Herein, we studied the role of XCL1 signaling in these processes.

Morphometric study of uninvolved rectal mucosa 10 cm and 20 cm away from the malignant tumor.

Recently, many details of the interplay between tumor cells and tumor-associated stromal elements leading to the progression of malignant disease were elucidated. In contrast, little is known about the role of uninvolved stromal tissue in the remote surrounding of the malignant tumor. Therefore, we performed a computer-aided morphometric study of rectal mucosa in samples taken 10 cm and 20 cm away from the malignant tumor during endoscopic examination of 23 patients older than 60 years.

Metallophilic macrophages of the rodent thymus.

For a very long time, we studied the metallophilic macrophages of the rodent thymus and in this review our results on morphological, histochemical, enzymehistochemical, immunohistochemical, ultrastructural and functional features of these cells, as well as the molecular regulation of their development, will be presented. Furthermore, the differences between species will also be discussed and the comparisons with similar/related cell types (metallophilic macrophages in the marginal sinus of the spleen, subcapsular sinus of the lymph nodes and germinal centers of secondary lymphoid follicles) will be made. Metallophilic macrophages are strategically positioned in the thymic cortico-medullary zone and are very likely to be involved in: (i) the metabolism, synthesis and production of bioactive lipids, most likely arachidonic acid metabolites, based on their histochemical and enzymehistochemical features, and (ii) the process of negative selection that occurs in the thymus, based on their ultrastructural features and their reactivity after the application of toxic or immunosuppressive/immunomodulatory agents.

Lipopolysaccharide-induced in vivo activation of follicular dendritic cells is tumor necrosis factor receptor-1 independent.

It is well recognized that tumor necrosis factor receptor-1 (TNFR1) signaling pathway (with lymphotoxin-β receptor) is of critical importance for the development, activation, and clustering of follicular dendritic cells (FDCs) within the lymphoid follicles. However, further information on the molecular control of these processes is very sparse. Here, we show that intravenous application of lipopolysaccharide induces the clear and prominent morphological signs of FDC development and activation in vivo, which is independent of TNFR1 pathway.

Role of CCL19/21 and its possible signaling through CXCR3 in development of metallophilic macrophages in the mouse thymus.

We have already shown that metallophilic macrophages, which represent an important component in the thymus physiology, are lacking in lymphotoxin-β receptor-deficient mice. However, further molecular requirements for the development and correct tissue positioning of these cells are unknown. To this end, we studied a panel of mice deficient in different chemokine ligand or receptor genes.

TNF receptor-1 is required for the formation of splenic compartments during adult, but not embryonic life.

Lymphotoxin β-receptor (LTβR) and TNF receptor-1 (TNFR1) are important for the development of secondary lymphoid organs during embryonic life. The significance of LTβR and TNFR1 for the formation of lymphoid tissue during adult life is not well understood. Immunohistochemistry, morphometry, flow cytometry, and laser microdissection were used to compare wild-type, LTβR(-/-), TNFR1(-/-) spleens with splenic tissue that has been newly formed 8 wk after avascular implantation into adult mice.

Morphometric study of healthy jejunal and ileal mucosa in adult and aged subjects.

Small intestine mucosa is often affected with malabsorptive, autoimmune and inflammatory pathological processes. However, morphometric data on the healthy human small intestine mucosa, especially ileum, are scarce. We aimed to obtain histoquantitative data on the healthy jejunal and ileal mucosa and assess the effects of gender and ageing on these parameters.

Ultrastructure of medullary thymic epithelial cells of autoimmune regulator (Aire)-deficient mice.

The significance of the autoimmune regulator (Aire) transcription regulator in establishing central tolerance has recently been elucidated in great detail. Still, the role of Aire in medullary thymic epithelial cell (mTEC) physiology is not fully understood. To shed more light on this issue, we studied the ultrastructure of mTECs in Aire-deficient thymus.

Stereologic analysis of tissue compartments of gunshot-injured and blunt-injured spleen.

The spleen is composed of several tissue compartments and the respective histoquantitative data are essential for complete understanding of immune or pathological processes in this organ. The aim of our study was to determine and compare the stereologic parameters of all tissue compartments of the gunshot-injured and blunt-injured human spleen. The model-based stereology with point-counting method was utilized to study the volume densities of red pulp, perifollicular zone, marginal zone, white pulp (follicles and periarteriolar lymphoid sheath), and connective tissue.

Metallophilic macrophages are fully developed in the thymus of autoimmune regulator (Aire)-deficient mice.

Thymic metallophilic macrophages represent a significant component in the thymus physiology. Recently, we showed their presence to be dependent on functional lymphotoxin-beta receptor (LT beta R) signaling pathway. However, it is unknown whether the development of metallophilic macrophages also requires the Autoimmune regulator (Aire) transcription factor, as suggested by some studies for medullary thymic epithelial cells, or perhaps the presence of Aire-expressing thymic epithelial cells themselves.

Histomorphometric characteristics of peritoneal blood microvessels.

We assessed histological characteristics and sex related differences in morphometric parameters of healthy persons' peritoneal blood vessels. Eighteen samples of parietal peritoneum were collected from 11 healthy persons with elective abdominal surgery, 6 males and 5 females, age range 44-58. Tissue samples were prepared for light and transmission electron microscopy.

Metallophilic macrophages are lacking in the thymus of lymphotoxin-beta receptor-deficient mice.

Lymphotoxin-beta receptor (LTbetaR) axis plays a crucial role in development and compartmentalization of peripheral lymphatic organs. But, it is also required for the appropriate function and maintenance of structural integrity of the thymus: in LTbetaR-deficient animals the clonal deletion of autoreactive lymphocytes is impaired and differentiation of thymic medullary epithelial cells is disturbed. In this study, using several markers, we showed that thymic metallophilic macrophages were lacking in LTbetaR-deficient mice.

T cells are required for the peripheral phase of B-cell maturation.

B-lymphocyte maturation is considered to be independent of the thymus. However, there is circumstantial evidence suggesting that it may be impaired in nude animals that lack the thymus. Our study shows that the proportion of immature B-lymphocyte subsets (CD90(high) IgM(high) and CD90(high) IgM(low)) was significantly increased, whereas that of mature B-lymphocyte subsets (CD90- IgM(low) and CD90- IgM(high)) was decreased in the blood and lymph nodes of nude rats.

Blood lymphocytes, monocytes and NK cells modulate their expression of CD44, ICAM-1, LFA-1 and MHC class II after arrival into lymphoid organs.

Adhesion molecules expressed on surface membranes of lymphocytes and other leukocytes enable their entry into the lymphoid and other tissues. However, little is known about molecules that govern the transit of leukocytes through the parenchyma of lymphoid organs proper. We show that in comparison to blood leukocytes, the corresponding cells isolated from lymphoid organs, i.

Thymus cell-cell interactions.

The recent advances in molecular biology and genetics, as well as the progress of in vitro techniques, have provided a more coherent image of the thymic function on the molecular level. But they have shifted the attention away from studies on the cellular level, which are necessary to clarify the biological roles of different cell types of the thymic microenvironment. The structure and function of the normal thymus depend on mutual interactions between thymocytes and nonlymphocyte cells.

Lymphocyte function-associated antigen-1 and intercellular adhesion molecule-1 expression on B-cell subsets and the effects of splenectomy-experimental studies.

There is an abundance of data dealing with recirculation of T cells in the rats, but relatively little is known about the traffic of B cells. The adhesion molecules expressed on the surface membrane are of great significance for recirculation of lymphocytes. However, very little is known about the expression of various adhesion molecules on B-cell subsets.