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Biomedical subjects

M Bilej

Publications and source records attributed to M Bilej.

At least 37 records · Page 2Linked to original sources
PubMed1993

The fate of protein antigen in earthworms: study in vivo.

Parenteral administration of antigen induces in the earthworms Lumbricus terrestris and Eisenia foetida the formation of antigen-binding protein. Labelled antigen was efficiently digested in the coelomic fluids of both species since the total amount of radioactivity in the coelomic fluids decreased. Antigen internalized in the free coelomocytes of both species was present in a TCA-precipitable form, although the decline of total radioactivity was higher than in the coelomic fluid, indicating that the TCA-nonprecipitable fragments are rapidly released from coelomocytes into the coelomic fluid. Within the first 24 h after administration, labelled antigen was detected throughout all tissues except for the epidermis and cuticle, and after 4 days it was found in the chloragogenic tissue around the gut, dorsal vein and typhlosole.

Animals↗
PubMed1993

The fate of protein antigen in earthworms: study in vitro.

Earthworm coelomocytes digest protein antigen in vitro. Proteolytic activity was detected both in cell-free coelomic fluid and in cell cultures of free coelomocytes which are effectors of earthworm immunodefense mechanisms. Antigen is cleaved either intracellularly or by proteolytic enzymes released by coelomocytes into the medium. Proteolysis was observed both in non-stimulated and antigen-stimulated cultures. Since significantly higher proteolysis was shown in supernatants from cultures of antigen-stimulated coelomocytes, we can assume that the release of proteolytic enzymes was inducible.

Animals↗
PubMed1992

The effect of an antigenic stimulation on proliferative response in athymic mice.

The proliferation activity of the main cellular categories of bone marrow after infusion of 3H-thymidine was studied in nu/nu and +/+ 1-month- and 3-month-old BALB/c mice in comparison with lymphoid cells in the spleen and mesenteric lymph nodes. The stem cell defect in nu/nu mouse bone marrow is compensated by an increased proliferation in myeloid series and in agranulocytes. The increase of proliferation activity among lymphoid cells in peripheral lymphoid organs was observed only in the 3-month-old mice with a delay in the nudes.

Animals↗
PubMed1992

Repeated antigenic challenge induces earthworm coelomocyte proliferation.

Annelids are able to protect themselves against foreign materials by natural and acquired cellular immunity. The aim of this study was to characterize the kinetic of antigen induced proliferation of earthworm coelomocytes. The proliferative activity of free coelomocytes of Eisenia foetida decreased after a second contact with the same antigen. Precursor cells in the mesenchymal lining of the coelomic cavity responded to stimulation immediately. These results indicate that for a successful triggering of the proliferative response of the free coelomocytes repeated contact with stimulating agents is needed.

Animals↗
PubMed1992

New trypsin inhibitors are present in the coelomic fluid of the earthworm Lumbricus terrestris.

Proteinase-inhibiting components of the coelomic fluid of the earthworm Lumbricus terrestris were examined. Inhibition of proteinases of serine, aspartate and thiol families was tested. Very strong inhibition was observed only in the case of trypsin. Additional data suggest that the inhibition is related to proteins of molar mass of 42 kDa and 20 kDa, respectively. These two proteins are present in the coelomic fluid in several forms which differ in their isoelectric points.

Animals↗
PubMed1991

The immunosuppressive effects of bilirubin.

The strong effects of bilirubin on various levels of the immune system are multifactorial. Concerning the mechanisms of these effects, we hypothesize that the primary causes of the described actions of bilirubin are the direct interaction of bilirubin molecules with cell membranes.

Bilirubin↗
PubMed1991

Characterization of antigen-binding protein in earthworms Lumbricus terrestris and Eisenia foetida.

Injection of antigen into the annelid worms Lumbricus terrestris (LT) and Eisenia foetida (EF) results in a marked increase of coelomic fluid protein concentration and the formation of a protein which binds the stimulating antigen (3). In this report we show that the increases in total protein concentration after first and second doses of antigen were higher and were achieved earlier in LT than in EF, while the accumulation of antigen-binding protein in coelomic fluid was similar in both species. Antigen-binding protein isolated by affinity chromatography retained its original binding activity. Its molecular weight in coelomic fluid as well as after isolation was 56 kD when analyzed by SDS-PAGE and immunoblotting. Under reducing conditions, two bands with mol./wt. 31 and 33 kD appeared which did not reveal detectable binding activity. This suggests that the 56 kD binding protein of annelids is composed of two disulphide-linked polypeptide chains both of which participate in antigen-binding site formation.

Animals↗
PubMed1991

Detection of antigen in the coelomocytes of the earthworm, Eisenia foetida (Annelida).

Earthworms, Eisenia foetida, are able to respond to antigenic stimulation by the formation of the antigen-binding molecules by coelomocytes--the effector cells of annelids' defence reactions. The ability to react with gold-labelled antigen was detected in agranular coelomocytes by electron microscopy. Furthermore, flow cytometry analysis used for quantitative evaluation of antigen binding showed significant increase of both antigen-binding cells and the amount of antigen bound per cell after stimulation. The antigen binding was inhibited by preincubation of cells with several similar proteins, although the most potent inhibitor was the immunizing antigen.

Animals↗
PubMed1991

Phagocytosis of synthetic particles in earthworms: absence of oxidative burst and possible role of lytic enzymes.

The mechanisms of phagocytized materials (synthetic HEMA particles, micrococci) by earthworm coelomocytes were examined. Despite the fact that coelomocytes have a high phagocytic activity, the chemiluminescent assay did not reveal increased production of oxygen radicals. Ultrastructural changes of engulfed particles observed by electron microscopy may be caused by intracellular lytic enzymes.

Animals↗
PubMed1990

In vitro antigen-binding properties of coelomocytes of Eisenia foetida (Annelida).

Annelids are capable of cellular and humoral defence reactions against foreign antigens. The main aim of this study was to characterise the antigen-binding properties of coelomocytes of Eisenia foetida by means of quantitative autoradiography and direct measurement of radioactivity. It was found that the antigen-binding capacity was significantly increased after antigen stimulation. Furthermore, the preincubation of coelomocytes with non-labelled proteins reduced the binding of radiolabelled antigen. The highest level of inhibition was found when the same protein was used for preincubation. These results indicate that antigen-binding properties are to some extent specific.

Animals↗
PubMed1990

Phagocytosis of synthetic particles in earthworms. Effect of antigenic stimulation and opsonization.

We examined the phagocytic activity of coelomocytes in earthworms Lumbricus terrestris. The synthetic polymeric HEMA particles were used in this study. The phagocytic capacity was increased after the protein administration or preincubation of HEMA particles with coelomic fluid. Furthermore, we isolated and characterized the proteins adsorbed on the surface of the particles which have opsonin-like properties.

Animals↗
PubMed1989

The stimulatory effect of bilirubin on phagocytic activity.

The effect of an i.p. application of bilirubin on phagocytic activity and the arrangement of the microtubule system of murine peritoneal macrophages were examined. A significant increase of phagocytic activity was observed 3 h after bilirubin treatment, and normal value were reached after 3 d. The increase of the extent of the microtubule system was comparable with that of enhanced phagocytosis but normal values were observed after 1 d.

Animals↗
PubMed1989

Biocompatibility of N-(2-hydroxypropyl) methacrylamide copolymers containing adriamycin. Immunogenicity, and effect on haematopoietic stem cells in bone marrow in vivo and mouse splenocytes and human peripheral blood lymphocytes in vitro.

N-(2-hydroxypropyl)methacrylamide polymeric prodrugs containing adriamycin bound to polymers via glycylphenylalanylleucylglycine side chains and, in one case, galactosamine bound via the same sequence, were tested for immunogenicity after intravenous, subcutaneous and oral application in two inbred strains of mice. The serum antibody level was determined by enzyme-linked immunoassay on the 3rd and 6th day after the last treatment. It was found that antibodies were only produced in very small amounts. In some experimental groups, the antibody titres measured following administration of copolymer conjugate were comparable with those present in non-treated controls. Attachment of adriamycin to N-(2-hydroxypropyl)methacrylamide copolymer considerably decreased its toxicity against haematopoietic precursors in bone marrow as measured by the in vivo colony-forming unit-spleen assay and its ability to inhibit [3H] thymidine incorporation by mouse splenocytes and human peripheral blood lymphocytes measured in vitro.

Animals↗
PubMed1989

The transmembrane and intracellular transport of drugs: interactions with the cytoskeletal network.

The transport of molecules and/or larger corpuscular material into the cells takes place in plasma membrane and plasma membrane-derived vesicles and vacuoles. Transmembrane and intracellular transport of various materials plays an essential role in the final cellular effects of the drugs. Cytoskeletal network forms a three-dimensional array in the cytoplasm of cells and is closely related to the plasma membrane. Thus, the cytoskeleton significantly affects various processes such as endocytosis, organization and fluidity of the membrane, activity of ion channels, or localization of intracellular organelles. The interactions of the cytoskeletal system with cellular transport of drugs are the scope of this article.

Animals↗
PubMed1988

Effects of bilirubin on murine peritoneal and spleen cells.

The effect of bilirubin on murine peritoneal and spleen cells was investigated. Bilirubin was found to have a strong and rapid effect on the expression of various kinds of Fc receptors on peritoneal macrophages. Significant changes were observed 30 min after the infection of bilirubin. The return to normal values was not observed earlier than after 24 h. The effect of bilirubin on Fc receptor expression of splenic macrophages was less pronounced. Expression of Ia antigen on macrophages was not influenced by bilirubin. The changes in percentage of sIg+ and Thy 1.2+ lymphocytes reflect a change in the ratio of T to B cells in the peritoneal cavity, as bilirubin caused 40% increase in numbers of B cells and a similar decrease in numbers of T cells. The percentage of splenic B lymphocytes was not influenced by bilirubin injection; but the ratio of T helper to suppressor cells was altered.

Animals↗