PubMed Health⌕ Search

Biomedical subjects

L Kolodie

Publications and source records attributed to L Kolodie.

At least 19 recordsLinked to original sources
PubMed1998

Residual bodies stimulate rat Sertoli cell plasminogen activator activity.

Previous studies suggested indirectly that residual bodies (RB) may play a role in the regulation of the proteolytic system within the testis and in the coordination of the spermatogenetic process. In the present study, we examined the effects of RB recovered from adult rat testes by centrifugal elutriation on Sertoli cell plasminogen activator (PA) levels, by zymography and ELISA procedures. Addition of RB to Sertoli cell cultures prepared from 20-day-old rat testes resulted in a dramatic stimulation of PA. Effects were dose- and time-dependent. Phagocytosis of RB by Sertoli cells leads to a rapid stimulation of Sertoli cell interleukin-1alpha (IL-1alpha), a cytokine potentially involved in the regulation of spermatogenesis; the effects of IL-1alpha were investigated. We found that IL-1alpha augmented PA levels and that immunodepletion of Sertoli cell-RB cocultures with anti-IL-1alpha antibodies abrogated the stimulatory effects of RB on PA. Together, the present findings indicate that RB enhance Sertoli cell PA and that IL-1alpha may be involved in that control.

Animals↗
PubMed1998

Effects of two sex steroids (17beta estradiol and testosterone) on proliferation and clonal growth of the human monoblastic leukemia cell line, U937.

We investigated the effects of two sex steroids (17beta estradiol and testosterone) on five human leukemia cell lines. We observed a statistically significant inhibition of proliferation, dose and time dependent, of the human monoblastic leukemia cell line U937. This inhibition was associated with a dose dependent decrease in the number of CFU-blasts in clonogenic cultures. Cytostatic effect was obtained with doses of 5 microM for estrogen and 10 microM for androgen and was not due to a non-specific cytotoxic effect, some cell viability remained high (> 90%) even after 6 days of incubation. More accurately, we demonstrated that growth inhibition was associated with a cell cycle arrest, U937 cells accumulating in G2/M phase. This blockade was dose related with a maximum number of cells accumulating at day 4. Sensitivity of these cells to an S-phase specific agent (hydroxyurea) was not increased, suggesting that these cells were blocked in G2/M and did not undergo mitosis. Expression in U937 cells of high affinity nuclear receptors for estrogen and androgen was negative which was in favour of a type II estrogen binding site, mediated mechanism. Moreover, a small fraction of these cells underwent apoptosis or differentiation with about 12% apoptotic cells and a significant increase (more than 30%) of two myelomonocytic markers (CD13 and CD64). These results demonstrate that the proliferation of some leukemic cells may be inhibited by micromolar concentrations of sex steroids, independently of nuclear receptor expression. The main mechanism seems to be a block in cell cycle associated with modulation of apoptosis and differentiation. It provided additional evidence for the potential value of sex steroids and their analogues in the treatment of leukemias.

Apoptosis↗
PubMed1997

Effects of retinoic acid on a new human erythromegakaryocytic cell line AP-217.

We have characterized a new human cell line AP-217, derived from the peripheral blood of a patient with chronic myeloid leukemia in blastic crisis. The analysis of cell surface antigens and ploidy showed that AP-217 was an erythro-megakaryocytic cell line. The effects of inducers of differentiation were studied and focused on retinoic acid (RA). Uninduced AP-217 cells produced a low level of hemoglobin (Hb) that showed a moderate but significant dose-dependent increase after 13 cis-RA induction (four times above the control at 10(-5) M). To outline this effect, AP-217 cells were cloned at limiting dilution. A subclone (clone 2) was isolated which expressed glycophorin A on 12% of cells, and showed a marked sensitivity to RA. After a 4 day induction with increasing concentrations of RA (1-10 x 10(-6) M) Hb production by clone 2 cells was enhanced 12 times over the control at the highest concentration (10(-5) M). No effect of RA on the Hb production of K-562 and HEL was observed. This increased Hb production occurred simultaneously with a growth inhibition in clonogenic cultures (20% reduction) associated with a drastic reduction of the colony size. Moreover, we demonstrated the expression of mRNA for the beta globin gene in clone 2 and AP-217-cells. This is the first report of a positive effect of RA on the erythroid differentiation of a human leukemic cell line.

Adult↗
PubMed1994

Image analysis as a tool for quantitative enzyme determination at the cellular level: application for monocytic differentiation of the UM-384 cell line.

Image analysis has been used to determined enzyme activity at the cellular level in individual smeared cells. The counterstains used to visualize smeared cells were chosen to avoid overlap with the chromogene. The amount of the reaction product was quantified by computerised scanning cytophotometry when the conditions of incubation, time and temperature of the reaction, and substrate concentration varied. Under optimal conditions for time, temperature and substrate concentration, a linear relationship was found between enzyme activity determined on smeared cells and in cell lysate. Using these defined conditions, differentiation of UM-384 cells was studied by measuring enzyme activity. After a monocytic differentiation process, induced by sodium butyrate, non-specific esterase cell activity was compared either with differentiation markers (HLA-DR, plasminogen activator inhibitor type 2 and lysozyme) or with markers of proliferation (DNA content) or functional properties (nitroblue tetrazolium reduction and phagocytosis). The results show that, using image analysis, non-specific esterase seems to be a useful means for the assessment of monocytic differentiation whereas myeloperoxidase is not. More generally, quantification of enzyme activity at the cellular level using image analysis can be applied to the study of the differentiation process and may help in the classification of leukemic cells.

Acid Phosphatase↗
PubMed1993

Absence of both subunits of cytochrome b558 in the UM384 cell line relative to the inability to generate superoxide anions.

Phagocytic cells are characterized by their ability to generate superoxide anions upon activation by appropriate stimuli. UM384, a myelomonocytic cell line, was shown to be defective in this oxidase activity as measured by nitroblue tetrazolium or cytochrome c reduction. Cytochrome b558, a unique pigment present in phagocytes and implicated in electron transfer from NADPH to O2, was absent in the differentiated UM384 cells. Both subunits of the cytochrome b558 appeared to be absent or present in strongly reduced amounts compared to the mother cell line U937, as indicated by immunocytochemistry or Western blot analysis using monoclonal antibodies (MABs). On the other hand, cytosolic factors also involved in NADPH oxidase activity were shown to be present, either immunologically or by using the capacity of the cytosol to activate the oxidase in a membrane fraction from bovine neutrophils. At the molecular level, the mRNA that encodes the gp91-phox was shown to be absent in the differentiated UM384 cells, whereas the mRNA that encodes the p22-phox was normally expressed. These results suggest that the defect in superoxide production by the UM384 cells is related to the absence of cytochrome b558, a situation mimicking that observed in phagocytes from patients with X-linked chronic granulomatous disease (X-CGD).

Antibodies, Monoclonal↗
PubMed1991

Quantification by image analysis of immunocytochemical reactions: application for determination of lysozyme content in individual smeared cells.

The objective of the present study was to develop a cytophotometric technique to quantitate immunocytochemical reactions. Cell antigens were detected after immunophosphatase alkaline staining procedure. The amount of reaction product was quantitated by computerized scanning cytophotometry. The technical conditions (dilution of primary antibody; incubation time of the three antibodies; volume and pH of the enzyme substrate reaction; storage of the slides) required for optimal cytophotometric determination of the reaction product were determined. Under these optimally defined conditions, a linear relationship between cell protein content (lysozyme) and microdensitometric measure of the colored reaction product was found. This method could be used for other cells, antigens, and enzymatic indicators.

Alkaline Phosphatase↗
PubMed1989

Plasmodium falciparum growth inhibition by human platelets in vitro.

Platelets take an active part in immunological processes as well as in haemostasis, especially in the host-parasite relationship. Our aim is to assess the growth of Plasmodium falciparum, cultured in human erythrocytes in the presence of fresh washed human platelets, since thrombocytopaenia is frequently observed during malarial infections. Our results show that platelets induce a dose-related growth inhibition of P. falciparum. Both proliferation and maturation of intraerythrocytic stages of the parasite are inhibited. This growth inhibition is triggered by the parasite itself as neither specific antibodies nor any other components are needed to activate platelets. Activated platelets are directly toxic since complement is not involved. Furthermore, inhibition is not mediated by erythrocyte lysis or by toxic oxygen metabolites. Platelets induce an inhibition of P. falciparum growth, at least in vitro, although the importance of their role played in vivo in malarial immunity has yet to be evaluated.

Animals↗
PubMed1989

Establishment and characterization of a granulocytic subclone (UM 384) from the monoblastic cell line U 937.

The human cell line U 937 spontaneously expresses monocytic maturation and can be induced into macrophage-like cells when treated with retinoic acid, sodium butyrate, or 2,3-O-tetra decanoylphorbol-13-acetate. We have selected a subclone, designated UM 384, that expresses granulocytic characteristics and can be induced to mature to granulocytes after exposure to retinoic acid, actinomycin D, and dimethylsulfoxide, and to monocyte-like cells when treated with sodium butyrate and phytohemagglutinin-stimulated leukocyte-conditioned medium. These cells retain the same constitutive markers as the parent line including histocompatibility leukocyte antigens and karyotype but share numerous chromosomal abnormalities, mainly t(X;8) (p21;q12).

Antigens, Differentiation↗
PubMed1984

Protein C level at birth.

The protein C level was determined, on cord blood, for 30 healthy newborns by electro-immuno assay using a monospecific antiserum. For the newborns the mean level of protein C related antigen is about one third of normal adults' mean level. There is a good correlation between Protein C related antigen and prothrombin related antigen. The low level of these vitamin-K-dependent proteins is probably a consequence of partial liver immaturity at birth. Using two-dimensional immuno-electrophoresis we were unable to detect subcarboxylated forms of protein C. However these abnormal forms could be seen in vitamin-K deficiencies of neonates.

Administration, Oral↗
PubMed1978

[Results of a one year study of Trombolab (author's transl)].

The Trombolab apparatus was purchased to measure thromboplastin time and recalcification clotting time automatically. For this last test, we have not been able to get satisfactory results. However, Thrombolab gives dependable and reproducible results for the thromboplastin time. Its use is easy and its maintenance simple.

Autoanalysis↗