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Biomedical subjects

K Nouza

Publications and source records attributed to K Nouza.

At least 73 records · Page 4Linked to original sources
PubMed1978

"Nucleolar test" as a system for screening and analysis of immunosuppressive activity of chemical and biological agents.

The numbers and nucleolar activity of lymphocytes were followed in the control and SRBC-stimulated popliteal lymph nodes following administration of known immunosuppressive agents of different classes which were given in doses effective in the Jerne test and graft-versus-host reaction. Immunosuppressive agents had a non-selective effect on different lymphocyte populations (characterized by the activity of nucleolar RNA synthesis) in the control, antigen-untreated lymph nodes, but had a marked inhibitory effect on lymphocytes with compact nucleoli in the antigen-stimulated lymph nodes. This decrease is in good correlation with suppression of the Jerne haemolytic plaques and GVHR. The nucleolar test as a simple technique appears to be adequate for a rapid screening of immunosuppressive activity of the chemical and biological agents.

Animals↗
PubMed1977

Time dependence of the effect of splenectomy on graft-versus-host reactivity of lymph node cells.

Changes in cell-mediated reactivity of lymph node cells at various intervals after splenectomy were investigated in three assays measuring the GVH reactivity of parental cells in F1 hybrids --splenomegaly test in very young recipients and popliteal lymph node enlargement assay in adults measuring the proliferative component of the reaction, and mortality assay in sublethally irradiated recipients measuring the killer activity of the cell inoculum. During the early postsplenectomy period the reactivity of the particular amounts of lymph node cells was lower than that of cells from normal donors, but at about 3 weeks after splenectomy it was higher. The increase was of short duration in the proliferation assay and at 5 weeks the reactivity declined markedly below the control values. The increase in activity persisted for 5 weeks after splenectomy in the "killer" assay. It is probable that the described changes in cell-mediated reactivity are involved in the total effect of splenectomy on the host's complex immune response, especially against normal and tumour allografts.

Animals↗
PubMed1977

Nucleolar and functional characterization of lymphocytes following cyclophosphamide treatment.

Profound lymphocyte depletion occurs in thymus, lymph nodes and spleens of normal and thymectomized mice early after a single high sublethal dose of cyclophosphamide. Among individual lymphocytes characterized by the different types of nucleolus, the "non-activable" lymphocytes with micronucleoli are affected most markedly by CY, whereas the proportion of the "active" lymphocytes is increased (up to 70% in the spleens). During the period of regeneration lymphocytes with micronucleoli increase rapidly, the increment thereof is very high on day 14 in the spleens of all mice, and still higher in the blood and lymph nodes of thymectomized animals. During the period of lymphocytopenia, in spite of the increased proportion of the "active" lymphocytes, the ability of residual cells of elicit GVH reactions and to incorporate 14C-uridine decreases. In contrast to changes in the early period, the recovery of the "active" lymphocytes and GVH reactivity, which is still incomplete on day 14, depends on the presence of an intact thymus.

Animals↗
PubMed1976

Cytotoxicity of normal rabbit serum for chicken lymphoid cells. I. Localization of the activity.

Normal rabbit sera were found to be highly cytotoxic for chicken thymus cells. When the sera were fractionated on Sephadex G-200, the natural cytotoixc activity resided exclusively in the first peak. It was found to be complement-dependent and heat stable at 56 degrees. On the other hand, in the serum of immunized animals the specific cytotoxic activity appeared in the second peak.

Animals↗
PubMed1976

Influence of the properties of skin allografts on the "graft survival promoting effect" of antilymphocyte serum.

Changes in the properties of non-H-2 imcompatible skin allografts, resulting from treating the graft donors with whole-body irradiation, antilymphocyte serum, cyclophosphamide, hydrocortisone, amethopterin and azathioprine, affected differently their survival in the recipients pretreated with normal and antilymphocyte serum. While in NS--pretreated recipients the modified grafts showed the tendency for a prolonged survival, in ALS-pretreated recipients they survived for a shorter time than normal allografts. In ALS-pretreated recipients, also allografts from radiation chimaeras, whose blood-forming system was of the recipient's genotype, survived worse than normal allografts and grafts from the donor syngeneic radiation chimaeras. The findings indicate that a normal physiological state of the graft is necessary for the induction and working of the protective components of the allotrasplantation reaction involved in the graft survival promoting effect of ALS. The significance of passenger leucocytes and of the functional properties of the graft, especially of the reparation cellular and extracellular processes is discussed.

Animals↗
PubMed1976

Effect of immunosuppressive drugs on an in vito correlate of cell-mediated immunity. The migration inhibition test.

The effect of a number of immunosuppressive drugs on the migration-inhibition test was studied. These drugs could be divided into four categories: (1) drugs influencing both the MIF production and MIF effect on macrophages (amethopterin, azathioprine); (2) drugs influencing MIF production (puromycin, actinomycin D); (3) drugs influencing the effect of MIF on macrophages (hydrocortisone); (4) drugs without any influence.

Animals↗
PubMed1975

Study of thymus and peripheral lymphocyte populations characterized by the dominant nucleolar type.

In neonatally thymectomized mice and in "B" mice obtained by adult thymectomy, lethal irradiation and repopulation with foetal liver cells, blood lymphocytes were classified according to their nucleolar morphology as revealed by toluidine blue staining. A majority of the "active", i.e., RNA-synthesizing cells were found to be thymus-dependent. Direct evidence was obtained by testing the "active" lymphocytes for their sensitivity to anti- serum in vitro. During postnatal ontogenesis, the frequency distribution of individual nucleolar types of lymphocytes tends to reflect the developmental changes in the organ tested. The decline of "active" lymphocytes in the thymus has its counterpart in their increase in the lymph nodes and peripheral blood. In hydrocortisone-treated mice, the most affected lymphocytes were those from the thymus cortex -- both the prevalent population of cells with micronucleoli and the "active" lymphocytes -- whereas the active small lymphocytes in the medulla (resembling those from peripheral blood and probably also their precursors) were relatively hydrocortisone-resistant.

Animals↗