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Biomedical subjects

J Gabrilovac

Publications and source records attributed to J Gabrilovac.

At least 37 records · Page 2Linked to original sources
PubMed1988

Defects of natural killer cell activity in children with untreated acute lymphocytic leukemia.

Natural killer (NK) activity against cells of the K-562 line was significantly depressed in 12 of 18 children (66%) with untreated acute lymphocytic leukemia (ALL). No suppression of allogeneic NK activity was observed with sera of the patients, regardless of the level of NK depression. The ability of peripheral blood lymphocytes (PBLs) to suppress allogeneic NK activity was tested in two ALL patients - one with no detectable NK activity, and one with high NK activity. No NK-suppressive activity was found with PBLs of the areactive patient; PBLs of the reactive patients exhibited some suppressive activity, but only at a particular suppressor-to-effector cell ratio. Leukemic blasts were resistant to killing by autologous NK cells stimulated by IFN, as well as to killing by allogeneic, IFN-stimulated PBLs. Leukemic blasts of an ALL patient inhibited lysis of K-562 cells in an 18-h, but not in a 4-h NK assay. The inhibition could partly be reversed by pretreatment of ALL cells with alpha interferon, suggesting that the blasts might inhibit the lysis of K-562 targets in a competitive manner. Disturbed function and/or regulation of NK cells may influence attempts at NK cell activation by lymphokines.

Acute Disease↗
PubMed1988

NK cell activity and estrogen hormone levels during normal human pregnancy.

NK cell activity was determined in peripheral blood of 24 women during pregnancy, and compared to NK activity of 40 healthy nonpregnant women in generative age. An increase in the first trimester was followed by a significant decline of NK activity in the second trimester, and a further fall in the third trimester of pregnancy. The initial rise of NK activity was predominantly due to primigravidas, whereas the fall in the second trimester was mainly due to multigravidas. There was a significant negative correlation between NK activity and the increasing levels of estrogen hormones (beta-estradiol, estriol and estrone) in the sera of pregnant women. However, when analyzed for each trimester of pregnancy separately, a significant (p less than 0.02) negative correlation was only found with beta-estradiol, suggesting that high doses of this hormone could contribute to pregnancy-associated NK suppression.

Adolescent↗
PubMed1984

In vivo effect of progesteron and estrogen on thymus mass and T-cell functions in female mice.

Progesteron and estradiol, administered in doses equivalent to those used for therapy caused a marked transient reduction of the thymus mass, but did not affect the cellularity of other lymphoid organs. Humoral and cellular immune response of the hormone-treated mice was normal at the time of thymus involution. The same was true for the stem-cell differentiation capacity. The remaining thymus cells after hormone treatment showed increased DNA-synthesis.

Animals↗
PubMed1983

Use of antibody-coated polyacrylic plastic beads for semiquantitative determination of cell surface antigens.

Polyacrylic plastic beads coated with specific antibodies, which had previously been shown to bind specifically to cells carrying the related antigen, are shown to react quantitatively with the antigen on individual cells. The number of beads per cell which can be counted by simple microscopy is a measure of the amount of antigen accessible on the cell surface. The method may also be used in combination with other methods for cell surface antigens, such as immunofluorescence, for multiple antigen determination.

Animals↗
PubMed1983

Immunoregulatory properties and LP-pattern of human ovarian carcinoma ascites and pleural effusions of nonmalignant origin.

The immunoregulatory activity of ascitic fluids obtained from patients with ovarian carcinoma, and pleural effusions collected from patients with various nonmalignant diseases, was tested. The following assays were performed: in vivo, PFC-response of mouse splenocytes to SRBC; in vitro, antibody-dependent cellular cytotoxicity (ADCC), and phagocytic activity of human peripheral blood mononuclear cells (PBMoC). The migration ability of mouse splenocytes in the presence of ascitic fluids was also evaluated. Parallelly, lipid (triglyceride and cholesterol) and lipoprotein (high-density/HDL/, low-density/LDL/, and very-low-density/VLDL/) content in ascites and pleural effusions, were determined. Both types of fluids suppressed the PFC-response and inhibited phagocytosis of 51Cr-labeled sheep erythrocytes by PBMoC, but augmented ADCC of PBMoC against sheep erythrocytes. An elevation of VLDL and a decrease of HDL and LDL in ascitic fluids and pleural effusions, as compared to normal human sera, were found. There were similar changes in the cholesterol content of these lipoprotein fractions, i.e., an increase of VLDL- and a decrease of HDL- and LDL-cholesterol.

Animals↗
PubMed1982

Immunoregulatory activity of cell-free peritoneal washings of mice with Ehrlich ascitic carcinoma.

Cell-free peritoneal washings (PW) were collected from mice with Ehrlich ascitic carcinoma at various time intervals after tumor transplantation and tested on the immunosuppressive activity in vitro. Two assays were used: (1) stimulation of human peripheral blood lymphocytes by phytohemagglutinin (PHA) and (2) inhibition of human leukocyte migration with PPD. Fluids collected in the early phase of tumor growth (up to day 6) were ineffective, or weakly suppressive, and those collected in advanced and terminal stages of carcinoma development, were suppressive in both tests applied. Control cell-free peritoneal washings obtained from normal mice without the tumor exerted suppressive activity when adjusted to the same protein concentration as the PW from mice with Ehrlich carcinoma. This suggests that host's cells in tumor-bearing animals, rather than tumor cells themselves, may be responsible for the production of inhibitory substance(s). Cell-free peritoneal washings were also tested on their ability to influence the growth of Ehrlich carcinoma cells in vitro, as measured by 3H-thymidine incorporation. Samples collected from mice with advanced tumors stimulated the growth of tumor cells.

Animals↗
PubMed1981

Suppressive activity of cell-free ascites obtained from murine tumors. Soluble Fc receptor as a possible active agent.

It has been shown that cell-free ascites (CFA) from Ehrlich carcinoma, AKR leukemia, and CBA thymoma, which all had strong suppressive activity in vivo, inhibit EA-rosette formation, complement-dependent hemolysis, and agglutinate EA-complexes. Since these are the characteristics of soluble FcR the data suggest the presence of FcR in CFA tested. To test whether the suppressive activity observed in vivo was due to the soluble FcR and FcR-like fraction was absorbed out from CFA or Ehrlich carcinoma by means of antigen-antibody complexes. The isolated FcR-like fraction was strongly suppressive in vivo. Additional support for the proposition that soluble FcR might be one of the mediators of suppression in vivo was gained by testing cell-free supernatants (CFS) of cell-line cells known to shed off FcR into the medium. It could be shown that CFS of highly FcR positive K-562 cells inhibited PFC stronger than did the CFS of weakly FcR positive Raji cells.

Animals↗
PubMed1981

Somatostatin suppresses growth of murine myeloid leukemia in vivo.

Daily injections of somatostatin into mice with myeloid leukemia retarded the tumor growth. This myeloid leukemia is an insulin-dependent tumor (in that it grows more slowly in hypoinsulinemic diabetic mice than in nondiabetic animals). Since somatostatin decreased the level of immunoreactive insulin in mice with myeloid leukemia, and since the treatment with insulin abrogated the antileukemic effect of somatostatin, we attribute retarded growth of this leukemia to decreased secretion of insulin, caused by somatostatin.

Animals↗
PubMed1981

Hormonal changes in patients with haematological malignancies.

Levels of immunologically reactive insulin (IRI), growth hormone (GH), thyroxine, cortisol and ACTH in sera of patients with various haematological malignancies were determined. IRI and GH levels were increased in 80% of the patients regardless of the type of disease. IRI was more elevated in relapse than in remission. Cytostatic treatment returned IRI serum levels to normal. Thyroxine, ACTH and cortisol in serum were higher in only two percent of the patient with haematological malignancies.

Acute Disease↗
PubMed1980

Fc-receptor-bearing cells in spleen of mice injected with cell-free Ehrlich ascites fluid (EAF).

The kinetics of different cell populations (T and B) and subpopulations (one bearing easily releasable FcR and one bearing stable FcR) was followed in spleens of mice after one single i.p. injection of EAF. The number of FcR bearing cells doubled within 2-7 days after EAF injection. This increase was due to cells bearing temperature sensitive FcR and was accompanied by the doubling of theta positive cells. These results, supported by the demonstration of doubly labeled (theta+FcR+) cells, suggest that EAF injected into normal mice causes the appearance of T-cells expressing easily releasable FcR. These cells, according to Fridman et al. (1977) are suppressor cells. Maximal increase of theta positive cells and of cells with temperature sensitive FcR detected in vitro coincided with the maximum of the suppressive activity of EAF detected in vivo.

Animals↗
PubMed1977

Rosette forming cells in the spleens of mice with lymphoid and myeloid leukemia.

The kinetics of the appearance of direct (E) or induced (EA and EAC) rosettes in the spleens of mice inoculated with lymphoid and myeloid leukemias were followed under the assumption that leukemic infiltration of the spleens would result in progressive increase of rosette-forming cells if the malignant cells possessed appropriate receptors.

Animals↗
PubMed1976

Participation of leukemia cells in immune responses.

Cells of a transplantable lymphoid leukemia of mice were tested in vivo and in vitro to see which features of normal lymphoid cells were retained in spite of malignant transformation and lack of growth control. Leukemia cells phagocytosed, adhered to glass, possessed receptors for immunoglobulin, participated in the immune response against SRBC (probably by amplifying a normal response through attachement of antibodies on their surfaces), became recruited into inflammatory reactions elicited by grafting allogeneic of syngeneic skin, and apparently joined graft-versus-host and host-versus-graft reactions, contributing toward damage of hemopoietic target tissues.

Animals↗