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Predicting the functional preferences of the ligands was always a highly demanding task, much harder that predicting whether a ligand can bind to the receptor. This is because of significant similarities of agonists, antagonists and inverse agonists which are binding usually in the same binding site of the receptor and only small structural changes can push receptor toward a particular activation state. For G protein-coupled receptors, due to a large progress in crystallization techniques and also in receptor thermal stabilization, it was possible to obtain a large number of high-quality structures of complexes of these receptors with agonists and non-agonists. Additionally, the long-time-scale molecular dynamics simulations revealed how the activation processes of GPCRs can take place. Using both theoretical and experimental knowledge it was possible to employ many clever and sophisticated methods which can help to differentiate agonists and non-agonists, so one can interconvert them in search of the optimal drug.

Predicting the functional preferences of the ligands was always a highly demanding task, much harder that predicting whether a ligand can bind to the receptor. This is because of significant similarities of agonists, antagonists and inverse agonists which are binding usually in the same binding site of the receptor and only small structural changes can push receptor toward a particular activation state. For G protein-coupled receptors, due to a large progress in crystallization techniques and also in receptor thermal stabilization, it was possible to obtain a large number of high-quality structures of complexes of these receptors with agonists and non-agonists. Additionally, the long-time-scale molecular dynamics simulations revealed how the activation processes of GPCRs can take place. Using both theoretical and experimental knowledge it was possible to employ many clever and sophisticated methods which can help to differentiate agonists and non-agonists, so one can interconvert them in search of the optimal drug.

Aggressive fibromatosis (desmoid tumor) is a mesenchymal lesion originating from fascial, aponeurotic and muscular connective tissue. It rarely becomes histologically malignant. In this study we analyzed the cell cycle regulation proteins: pRb, p16, and proliferating antigens: Ki-67, PCNA, MCM5 with immunohistochemical method in archival material derived from 27 extra-abdominal (E-AD), 18 abdominal (AD) and 5 intra-abdominal (I-AD) cases of desmoid tumor. None of the examined cases (n=50) of aggressive fibromatosis was pRb-immunonegative. Heterogeneous expression of pRb was observed in 51.85% (14/27) of Group AD cases and in 5.56% (1/18) of Group E-AD cases; positive expression in 48,15% (13/27) of Group AD cases, in 94.44% (17/18) of Group E-AD cases, and in 100% (5/5) of Group I-AD cases. There were no negative cases for p16 staining in any of the examined groups. The number of heterogeneous cases in individual groups was: 33.33% (9/27) in Group AD, 50% (9/18) in Group E-AD and 40% (2/5) in Group I-AD, and positive cases: 66.67% (18/27), 50% (9/18) and 60% (3/5), respectively. Overexpression of PCNA was noted in 98% (49/50) of cases. The positive staining for Ki-67 protein was noted in 25.93% (7/27) in Group AD, in 16.67% (3/18) in Group E-AD and in 60% (3/5) in Group I-AD. None of the examined cases was immunopositive for MCM5 protein. The noted levels of pRb and p16 expression in desmoid cells reflect their function in cell cycle regulation. Probably the unsettled cell cycle progression, especially in G1 phase, is not the cause of aggressive fibromatosis pathogenesis.

Aggressive fibromatosis (desmoid tumor) is an uncommon locally invasive non-metastasizing neoplasm lesion. Desmoid tumor consists of fibroblasts, miofibroblasts and a significant amount of extracellular matrix. p27KIP1 (p27) protein is a member of the universal cyclin-dependent kinase inhibitor (CDKI) family that regulates progression through the cell cycle. In various human neoplasms the decreased level of p27 was observed. There were analysed 42 specimens of aggressive fibromatosis, in which there were 24 abdominal and 18 extra-abdominal cases. There was performed immunohistochemical analysis employing a monoclonal antibody against p27 protein and Ki-67 (Novocastra, UK). The sections for immunohistochemical study were stained using the streptavidin - biotin method. The average percentage of cells stained positively for all cases for p27 and Ki-67 was 22.1% (SD=29.2) and 6.0% (SD=8.8) respectively. There was no statistically significant difference between Ki-67 or p27 expression in abdominal and extra-abdominal location. Analysis of p27 and Ki-67 expression levels might indicate that low proliferating activity of desmoid fibroblasts is connected with another mechanism than the one, in which p27 takes part.

Aggressive fibromatosis, usually termed desmoid tumor, develops from muscle connective tissue, fasciae and aponeuroses. Aggressive fibromatosis located in various parts of the body demonstrates differentiated biological behavior. Abnormalities in TGF-beta expression are very common in many disease processes, including neoplasms. Immunohistochemical analysis employing a monoclonal antibody against TGF-beta was performed on archival material, consisting of 38 cases of aggressive fibromatosis, among which 23 represented abdominal, 11 extra-abdominal and 4 intra-abdominal localizations. The sections for immunohistochemical study were stained using the streptavidin-biotin (ABC) method. The average percentage of cells positively stained for TGF-beta protein was 40.2% in the group of extra-abdominal, 58.5% in the group of abdominal and 72.8% in the group of intra-abdominal localizations. There were significant differences observed between the analyzed groups of desmoid tumor (p0.05). A positive cytoplasmic reaction for TGF-beta was noted in 65.8% (25/38) of the aggressive fibromatoses. Overexpression of TGF-beta protein was noted in 39.5% (15/38) of the aggressive fibromatoses. High expression noticed in desmoid fibroblasts might indicate that this protein plays a crucial role in the development of aggressive fibromatosis.

The aim of this study was to evaluate the correlation between NK (natural killers) cells in an inflammatory infiltration of the liver and in peripheral blood in children with chronic hepatitis type C.The study comprised 25 children with chronic hepatitis type C. The control group comprised 10 children with no liver disease in past medical history and normal activity of aminotransferases. In the study group, liver biopsy specimens were evaluated by histopathology and immunomorphology - the presence of NK cells present in the inflammatory infiltrate was determined. In all children the percentage and absolute count of NK cells in peripheral blood was evaluated by flow cytometry, as well as the activity of NK cells in relation to leukaemic cells of erythroleukemia K-562 without stimulation and after the stimulation with IL-2 (in vitro).In the studied group of children NK cells constituted 6.07 +/- 3.92 % of cells present in liver infiltrate. In peripheral blood NK cells constituted 11.68 +/- 6.73 % of white blood cells, and their absolute number was 241.08 +/- 128.56 /ml. The cytotoxic activity of NK cells in dilution E:T 25:1 was - 91.8 +/- 1.07 % and in dilution E:T 12.5:1 - 6.72 +/- 3.68 %. After stimulation with IL-2 it was 92.8 +/-1.01 % and 7.58 +/- 3.95 %, respectively. The number of NK cells in peripheral blood and cytotoxic activity of NK cells in the studied group did not differ from that of the control group. There was a positive correlation between the percentage of NK cells in the liver infiltrate and the absolute number of NK cells in the peripheral blood and between percentage of NK cells in the inflammatory infiltrate and cytotoxic activity of NK cells in peripheral blood, stimulated and non-stimulated with IL-2 in proportion E:T 12.5:1.Positive correlation between the number of NK cells in peripheral blood and liver infiltrate suggests the possibility of evaluating NK cells involvement in the pathogenesis of chronic hepatitis type C in children on the basis of peripheral blood tests.

The aim of the study was to assess the correlation between morphological and immunological features of lesions in the liver in children with chronic hepatitis C. In the study 11 children with chronic hepatitis C were enrolled. Histopathological and immunomorphological investigations included antigen marking CD45, CD45RA, CD45RO, CD20, CD3, CD8 in liver biopsy specimens. The immunomorphological assessment of the inflammatory infiltrate cells showed the presence of CD45 antigen on the vast majority of leukocytes in the portal tracts and in the lobular parenchyma in all the studied children. One fourth of the inflammatory cells were characterised by CD20 phenotype, 1/2--by CD3 phenotype, 1/3--by CD8 phenotype, 1/3--by CD45RA phenotype and 2/3--by CD45RO phenotype.T and B lymphocytes were predominant in hepatic inflammatory infiltrates (T lymphocytes are twice as numerous as B lymphocytes). Among T lymphocytes, cytotoxic and suppressor cells were prevailing. Most T lymphocytes were characterized by CD45RO phenotype, which shows their activation. A positive correlation between most lymphoid cell markers, staging and grading suggests the role of these cells in liver injury.