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Biomedical subjects

M Holub

Publications and source records attributed to M Holub.

At least 55 records · Page 3Linked to original sources
PubMed1990

Ossification in nude mice. 1. Macroscopical study.

Ossification was studied in cleared fetuses, newborns, 1- and 6-week-old nu/nu and nu/+ mice of the B 10 LP background. The same ossification pattern was observed in nu/nu and nu/+ in the embryonal period as well as in newborn animals and mice aged 1 or 6 weeks. On the other hand, 6-week-old nu/nu mice exhibited a lower X-ray density of the skeleton and a lower thickness of the proximal tibial growth plate than 6-week-old nu/+ litter mates. The results indicate the influence of postnatal factors on the skeletal development of nu/nu mice.

Animals↗
PubMed1990

Omental dendritic cells: Ia expression and relation to macrophages.

Rat omental dendritic cells (ODC) occur in two forms, mainly spindle-shaped, Ia-, on the surface, and stellar, Ia+ within the omentum. Like macrophages, most ODC label with W3/25 mAb and have a demonstrable activity of non-specific esterase, acid phosphatase and ATPase. Up to 30% of ODC are actively phagocytic. The proportion of Ia+ ODC rises 7 days after ip antigenic stimulation and there seems to be a reciprocal development of Ia positivity and phagocytic capacity between ODC and macrophages 3 and 5 days after ip immunization. ODC contribute to the overall fluctuation of Ia expression in the entire omentum after immunization. Ia+ ODC display a linear arrangement along preilymphatic spaces and may be related to the formation of new lymph vessels. They also constitute the stroma of pseudofollicles containing clusters of what are presumably T-helper lymphocytes closely attached to ODC, scattered suppressor T lymphocytes and B cells accumulating in later stages at the immune response.

Acid Phosphatase↗
PubMed1990

The dysgenetic thymus in nu/nu mice is a potent source of colony stimulating factor (CSF).

During in vitro incubation, the pulmonary and thymic tissue of mice released a colony stimulating factor (CSF) supporting the development of colonies of granulocytes and macrophages from bone marrow progenitors. Cardiac, splenic, renal and bone marrow tissues were not active. The dysgenetic thymus of nude mice was a very potent source of CSF during in vitro incubation.

Aging↗
PubMed1989

Foreign body reaction against cellophane in the athymic nude mice.

There are no differences in the multinucleate cell formation in normal and athymic mice after the subcutaneous implantation of a cellophane strip. The number of Ia+ epitheloid cells and multinucleate foreign body giant cells was lower and the number of epitheloid cells sharing the marker of activated macrophages (M 57) was higher in athymic compared to normal mice. The epitheloid cells of athymic and euthymic animals exhibited no difference in the expression of Mac-2 molecule. The difference of the expression of surface markers between athymic and euthymic animals does not influence the foreign body giant cell formation.

Animals↗
PubMed1988

Alpha-fetoprotein and phagocytosis in athymic nude mice.

Alpha-fetoprotein (AFP) was found to suppress the phagocytic activity of the blood monocytes and neutrophils in vitro. The amounts of AFP detectable by immunofluorescence in the livers of nu/nu, nu/+ and +/+ mice were quite comparable, and thus could not have been responsible for the alterations in phagocytosis found in leukocytes of athymic nude mice during their ontogenetic development.

Age Factors↗
PubMed1987

Changes in the microtubular skeleton of human lymphocytes produced by immunosuppressive substances.

The technique of immunofluorescent visualization of the microtubular skeleton of human lymphocytes isolated from the peripheral blood of healthy donors and immobilized on Concanavalin A--precoated slides was used. These lymphocyte monolayers are suitable for extraction and employment of indirect immunofluorescence. Using a monoclonal antitubulin antibody, one can visualize the MT apparatus of control human lymphocytes as an organizing centre with attached beamlike structures. Lymphocytes treated with ATG or monoclonal OKT 3 antibody in vitro manifest changes in the shape of cells, inhibition of the blast-like cell formation, and an atypical MT system: disturbance or even disappearance of the beamlike structure, formation of bundles and "caps" resulting, in some cases, in shedding of a part of cytoplasm. Rabbit ATG binds to all the cells of the monolayer, and can be shown even after cell extraction. Control experiments with nonspecific rabbit or murine IgG did not induce any of the above changes. Reorganization of the MT apparatus of human lymphocytes affected by ATG or OKT 3 in vitro can be explained either by a direct association of antigenic determinant with MT, or by the persistence or/and internalization and further processing of immune complexes of antigenic membrane determinants with specific antibodies.

Animals↗
PubMed1986

Puromycin aminonucleoside nephropathy: ultrastructure, glomerular polyanion, and cell surface markers.

Puromycin aminonucleoside nephropathy with heavy proteinuria and oedema was induced in rats by 10 consecutive daily subcutaneous injections of aminonucleoside (1.67 mg/100 g of body weight). The main ultrastructural lesions were vacuolation of podocytes and total fusion of foot processes with loss of colloidal iron-reactive polyanion layer on the epithelial surface adjacent to the basement membrane. On the other hand the outer surface of podocytes and intravacuolar granular substance stained with colloidal iron. In scanning electron microscopy of freeze-fractured tissue the swollen podocytes and the urinary spaces displayed granular and filamentous precipitates. Seven cell surface antigens were examined by indirect enzyme immunohistochemistry with a series of MRC OX monoclonal antibodies. Glomeruli of control rats exhibited rare isolated Ia- positive endocapillary cells, possibly monocytes; these elements were significantly reduced in puromycin aminonucleoside nephropathy but there was an increase in Ia- positive cells in the cortical interstitium. Control kidneys harboured scanty interstitial T lymphocytes. These latter, especially the T8- positive cytotoxic/suppressor subpopulation, were markedly augmented in puromycin aminonucleoside nephropathy. The expression of class I histocompatibility antigens and of differentiation antigens (Thy 1) was not altered by aminonucleoside.

Animals↗
PubMed1984

Enhanced phagocytic activity of blood leukocytes in athymic nude mice.

After 30-min incubation, blood leukocytes of adult athymic BALB/c nude mice (nu/nu) have a distinctly higher methacrylate or yeast particle uptake than leukocytes of euthymic nu/+ or +/+ mice. This permanent enhancement is not due to humoral factors, since the percentage of phagocytosing nu/nu leukocytes increases further in nu/+ littermate's plasma. Also, chronic infection or intraperitoneal immunization causes an additional transitory increase of the percentage of phagocytosing leukocytes and numbers of particles ingested; the phagocytic performance of leukocytes of euthymic mice is raised under these conditions by a greater factor. In fetuses enhanced phagocytosis of nu/nu mice is found only in monocytes. The bulk of ingestion of methacrylate particles is mediated by Fc receptors and significantly more receptors for IgG2B, IgG1, and IgG2A are demonstrable on nu/nu neutrophils; ingestion of particles via these receptors is again higher in nu/nu neutrophils, whereas nu/nu monocytes display a higher uptake via Fc(IgG1) receptors.

Animals↗
PubMed1984

The ovarian follicle as a model for the cell-mediated control of tissue growth.

Thy-1+ cells, producing Thy-1+ material, have been demonstrated by the indirect immunoperoxidase technique in the theca of growing ovarian follicles of the rat. OX-2 antigen, known as the minor glycoprotein of rat thymocytes, was detected in granulosa cells of non-growing follicles. Ia+ cells of dendritic type and/or activated macrophages were identified in the granulosa of advanced degenerating follicles, and remnants of the zona pellucida exhibited immunoglobulins. In some ovaries immunoglobulins were also bound to the zona pellucida of oocytes of early degenerating antral follicles. Medium-sized antral follicles with degenerating granulosa were occasionally invaded by cells carrying antigens of cytotoxic T lymphocytes or other T lymphocyte subsets, while degenerating large antral follicles were sometimes invaded by cells exhibiting antigen of cells with natural killer function (but not antigens of T lymphocytes). Granulosa cells of some degenerating antral follicles exhibited class-I antigens derived from the major histocompatibility complex. We suggest that cell-mediated control mechanisms of antigen expression and metabolism of tissue cells during their differentiation and degeneration should be considered in addition to the well-documented hormonal dependence of some tissues.

Animals↗
PubMed1984

Phagocytic uptake of synthetic particles in blood leukocytes of fetal and newborn athymic nude mice.

Monocytes are the main phagocytic element in the blood of fetal mice; monocytes of athymic nude mouse fetuses (gestation days 17-20) ingest in vitro, in full blood, significantly more synthetic (HEMA) particles than the monocytes of their euthymic littermates. Blood leukocytes of athymic fetuses also bear much higher densities of Fc receptors for IgG2B. The differences in phagocytic uptake in blood leukocytes disappear and the differences in Fc(IgG2B) receptors decrease at postnatal days 2 and 4.

Animals↗
PubMed1984

Experimental infection with Mycobacterium kansasii in athymic nude mice.

Subcutaneous infection with Mycobacterium kansasii did not cause mortality in athymic nu/nu and control nu/+ mice. It had a stimulatory activity comparable to obligatory mycobacterial pathogens: thymus-dependent lymphatic tissues areas were populated during the infection by lymphocytes also in nu/nu mice in which a low degree of migration inhibition factor production could be seen. In both models of chief site of mycobacterial trapping and phagocytosis was the hyperplastic interdigitating cell mesh in the thymus-dependent areas of lymph nodes. A detailed morphological description of the organ changes is given.

Animals↗
PubMed1984

Macrophages of athymic nude mice: Fc receptors, C receptors, phagocytic and pinocytic activities.

Expression of Fc receptors (FcR) for IgG1, IgG2A, IgG2B, IgM, IgA and IgE, binding of C3 and C5 complement components and phagocytic and pinocytic activities were determined in peritoneal and omental macrophages of nu/nu, nu/+ and +/+ Balb/c mice. nu/nu mice showed a higher proportion of FcR and complement receptor-bearing peritoneal macrophages along with a significantly higher phagocytic activity of peritoneal macrophages both in vitro and in vivo. Tests of pinocytic activity in these cells and phagocytic activity in omental phagocytes yielded similar results. We conclude that athymic mice compensate their immune defects by a higher phagocytic activity of their professional phagocytes and a higher expression of receptors mediating this process.

Animals↗