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D Guc

Publications and source records attributed to D Guc.

10 recordsLinked to original sources
PubMed2004

In vitro cytotoxicity of mitoxantrone-incorporated albumin microspheres on acute promyelocytic leukaemia cells.

In the present study, the preparation and characterization of bovine serum albumin (BSA) microspheres and the evaluation of the in vitro cytotoxicity of these microspheres on acute promyelocytic leukaemia (HL-60) cells were described. Mitoxantrone (MTZ)-incorporated microspheres were evaluated for particle size, drug loading, release characteristics and surface morphology. The biological effect of MTZ released from BSA microspheres was determined on an in vitro cultured HL-60 cell line, showing that, after encapsulation, MTZ still retains cytotoxic activity. For this purpose, methyl-thiazol-tetrazolium (MTT) assay was used to evaluate the in vitro cytotoxicity of MTZ-loaded microspheres. Particle size of BSA microspheres was determined between 17.61-20.38 microm and they were smooth and spherical in shape. Encapsulation efficiency of the drug-loaded microspheres was between 22.26-60.50%. For MTZ-containing microspheres, the cell death ratios were greater than 80% for all formulations. This study demonstrate that BSA microspheres were well suited for the controlled release of MTZ and were promising for anti-cancer chemotherapy.

Animals↗
PubMed2001

Comparison of the cytotoxic effects and smear layer removing capacity of oxidative potential water, NaOCl and EDTA.

UNLABELLED: This study compared the smear layer removing capability and cytotoxicity of NaOCl, EDTA and Oxidative Potential Water (OPW). Fifteen extracted single-rooted human upper incisors were examined in three groups. The root canals were enlarged to the apical foramen with K files to size #60 and irrigated with: (a) NaOCl followed by OPW, (b) OPW during and after instrumentation and (c) NaOCl followed by EDTA and NaOCl. The effect of these irrigants on the smear layer was evaluated using a scanning electron microscope. In vitro cytotoxicity of these irrigants was examined by MTT colorimetric assay. We found that the combination of NaOCl and OPW as well as the application of OPW alone, failed to remove the smear layer from the apical third, whereas the EDTA and NaOCl combination achieved complete removal. OPW, when used during and after instrumentation, removed the smear layer in the middle third more effectively than NaOCl followed by OPW. EDTA exerted more cytotoxic effects at all concentrations tested when compared with OPW and NaOCl. IN CONCLUSION: (a) OPW was less cytotoxic than other irrigants but did not effectively remove the smear layer, (b) treatment with EDTA followed by NaOCl efficiently removed of the smear layer, but their cytotoxicity should be considered during endodontic therapy.

Animals↗
PubMed2000

Expression of complement regulatory proteins CR1, DAF, MCP and CD59 in haematological malignancies.

Host cells are protected from the lytic effect of the complement system by complement regulatory proteins. This study was designed to investigate the expression of complement regulatory proteins on leukemic blasts which may be susceptible to the lytic effects of the complement system in the circulation. The surface expressions of complement regulatory proteins, complement receptor 1 (CR1, CD35), decay accelerating factor (DAF, CD55), and homologous restriction factor 20 (HRF20, CD59), on peripheral blood and bone marrow blasts were evaluated by using flow cytometry in 16 acute myeloblastic leukemia (AML), 16 acute lymphoblastic leukemia (ALL), 4 chronic lymphocytic leukemia (CLL), 3 chronic myelocytic leukemia (CML) patients and control granulocytes and lymphocytes obtained from 15 healthy volunteers. mRNA expression was investigated by Northern blot analysis. mRNA abundances were calculated after normalization according to 28s rRNA. Surface expressions of CRI and DAF were marginally (p = 0.08 and p = 0.08, respectively) lower in AML, and DAF expression was significantly lower (p=0.0008) in ALL patients in comparison to their normal counterparts. Except from a slight increase that is detected for CD59 in CML patients (p=0.06), there was no significant difference between the surface expressions of CD59 in any of the groups studied. Densitometric analysis of autoradiographs obtained from Northern blots revealed that in AML patients, CR1 mRNA expression were 5.5-fold lower than controls (p=0.06), while DAF mRNA expression was significantly higher (p=0.0046). Furthermore, the mRNA expression of CRI in ALL patients was found significantly lower than in the control group (p = 0.0419). None of the values obtained from the other groups were significantly different from each other. These results suggest that leukemic blasts are protected from the lytic attack of the complement system at all levels, since all of the complement membrane regulatory proteins were expressed in all leukemia types (although at lower amounts in some cases), and it is also possible to use CRI and DAF as differentiation markers in acute leukemias.

Antigens, CD↗
PubMed1999

Evaluation of the cytotoxicity of calcium phosphate root canal sealers by MTT assay.

The purpose of this study was to evaluate the cytotoxicity of some calcium phosphate-based sealers (Sankin apatite root canal sealers (SARCS) types 1 to 3) in comparison with currently used sealers (CRCS, Ketac Endo, AH26, and Endomethasone) by using MTT assay on L929 cells. Monolayer cell cultures were prepared on 96-well plates. After incubation at 37 degrees C in a humidified 5% CO2-containing air atmosphere for 24 h in the presence of each sealer extracts, 25 microliters of 5 mg/ml of MTT in saline were added into each well and incubated a further 3 h at 37 degrees C. A solubilization buffer consisting of 23% sodium dodecyl sulfate in 50% N,N-dimethylformamide (pH 4.7) was used to dissolve formazan precipitate. The optical densities of the plates were then read by a microplate spectrophotometer at 570 nm. Greater magnitude of optical density due to intense blue coloring is regarded as showing a higher percentage of cell viability. Among the different types of sealers, SARCS types 1 to 3 and CRCS did not exert any cytotoxic effects, whereas AH26, Ketac Endo, and Endomethasone produced some cytotoxicity.

Animals↗
PubMed1998

P-glycoprotein expression by technetium-99m-MIBI scintigraphy in hematologic malignancy.

UNLABELLED: Our aim was to ascertain the relationship between the degree of 99mTc-MIBI uptake and the level of p-glycoprotein (Pgp) expression determined by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR) techniques in patients with hematologic malignancy. METHODS: A total of 21 samples (19 patients) were evaluated. Two patients had repeat studies after therapy. Thirteen samples were studied at the time of initial diagnosis and 8 during relapse after therapy. After MIBI imaging, either bone marrow aspiration or peripheral blood was obtained for flow cytometric and RT-PCR analyses. Flow cytometry was performed using two different antibodies. After the injection of 555 MBq MIBI, whole-body and pelvic spot images were acquired using a dual-head gamma camera. The uptake in the bone marrow was evaluated against the background (adjacent soft tissue) by both qualitative (scoring system) and quantitative (tm/bkg ratios) analyses. RESULTS: For flow cytometry, the limit for Pgp overexpression was set at >15% Pgp-positive mononuclear bone marrow or peripheral blood cells. There was an inverse correlation between the levels of Pgp and MIBI imaging using both the qualitative (scoring system) and quantitative (tm/bkg ratios) analyses (p = 0.022). Mean values were statistically different between Pgp+ and Pgp- groups for both qualitative and quantitative analyses (p = 0.009 and 0.024, respectively). For RT-PCR, there was statistical support toward a difference in the mean values between Pgp+ and Pgp- groups by qualitative analysis (p = 0.061); however, no statistical difference was found between these two groups by quantitative analysis (p = 0.179). CONCLUSION: Based on the strong correlation between the imaging and flow cytometry and a statistical support toward the correlation between the imaging and RT-PCR, MIBI imaging may be used for the in vivo detection of Pgp in patients with hematologic malignancy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Expression of the components and regulatory proteins of the classical pathway of complement in normal and diseased synovium.

We studied the synthesis of the classical pathway complement components in synovial membrane. Ribonucleic acid was extracted from the synovial membranes of patients with rheumatoid arthritis (RA) or osteoarthritis (OA), as well as from normal synovial membrane. Northern blot and dot blot analysis showed that the mRNAs for all classical pathway complement components (C1qA chain, C1qB chain, C1qC chain, C1r, C1s, C4 and C2) and the fluid-phase regulatory components (C1-inhibitor, C4-bp and factor I) were present in all three types of synovial membrane. Thus, all the components of the classical pathway were expressed in normal and diseased synovium. In an attempt to determine which components were synthesised by each cell type, monocytes (mononuclear phagocytes), human umbilical vein endothelial cells (HUVEC), synovial membrane fibroblasts (from normal, OA and RA synovial membrane) and peripheral blood lymphocytes were cultured in vitro and secretion rates of individual components were measured and total cellular RNA was analysed by Northern blotting. Monocytes secreted C1q, C1r, C1s, C4, C2, C1-inhibitor and C4-bp but not factor I. Fibroblasts secreted C1r, C1s, C2, C3, C1-inhibitor and factor I but not C1q, C4 or C4-bp. HUVEC secreted C1s, C2, C1-inhibitor and factor I but not C1q, C1r, C4 or C4-bp. Lymphocytes did not secrete any of these components. In three instances mRNA was detected in the absence of secreted protein: mRNAs for the C1qA and C1qC chains were detected in HUVEC, whereas the mRNA for the C1qB chain was not, and C4 mRNA was detected in both fibroblasts and HUVEC.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1993

Expression of the components and regulatory proteins of the alternative complement pathway and the membrane attack complex in normal and diseased synovium.

We have studied synthesis of the complement components and regulatory proteins of the alternative pathway and the membrane attack complex in synovial membrane. RNA was extracted from synovial tissue of patients with rheumatoid arthritis (RA) or osteoarthritis (OA) as well as from normal synovial membrane. Dot blot analysis showed the presence of mRNAs for all the complement components and regulatory proteins (C3, factor B, factor D, C5, C6, C7, C9, factor H, factor I, S-protein, SP-40, 40, DAF, MCP, CR1, CD59), except for properdin, C8 alpha, C8 beta and C8 gamma in all three types of synovial membrane studied. In an attempt to determine which components were synthesised by each cell type, monocytes (mononuclear phagocytes), human umbilical vein endothelial cells (HUVEC), synovial membrane fibroblasts (from normal, OA and RA synovial membrane) and peripheral blood lymphocytes were cultured in vitro and secretion rates of individual components were measured and total cellular RNA analysed by northern blotting. Monocytes secreted properdin, C3, and factor H but not factor B, factor I, C5, C6, C7, C8 or C9. Fibroblasts and endothelial cells secreted factor B, factor H and factor I, but not properdin, C5, C6, C7, C8 or C9. Lymphocytes did not secrete any of these components. mRNAs encoding C3, factor B, factor H, S-protein, SP-40, 40, MCP and DAF were detected in all three other cell types (monocytes, fibroblasts and HU-VEC), but factor I and CD59 mRNAs were not detected in monocytes. C5, C6, C7, C8 alpha, C8 beta, CD8 gamma and C9 mRNAs were not detected in any of the cell types studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1993

Regulation of the synthesis of C1 subcomponents and C1-inhibitor.

We have investigated the synthesis of C1q, C1r, C1s and C1-inhibitor in HepG2 cells, human umbilical vein endothelial cells (HUVEC), fibroblasts (skin and synovial membrane), chondrocytes and monocytes. C1q was only synthesised by monocytes, although the mRNAs for the C1qA and C1qC chains were expressed in HUVEC. C1r, C1s and C1-inhibitor were synthesised by all cell types. The secretion rates of C1r and C1s were approximately equimolar in fibroblasts and chondrocytes whereas the secretion rate for C1s exceeded that for C1r in the other cell types. Molar ratios of C1s to C1r were approximately 2:1 for HepG2 cells, 5:1 for monocytes and 10:1 for HUVEC. Stimulation with interferon-gamma resulted in increased expression of all four proteins. The C1s:C1r ratio did not alter in chondrocytes or fibroblasts, but approached unity in HepG2, monocytes and HUVEC, due to relatively greater stimulation of C1r gene expression.

Carcinoma, Hepatocellular↗
PubMed1992

Effect of interferon-gamma on complement gene expression in different cell types.

We have studied the expression of the complement components C2, C3, factor B, C1 inhibitor (C1-inh), C4-binding protein (C4-bp) and factor H in human peripheral blood monocytes, skin fibroblasts, umbilical vein endothelial cells (HUVEC) and the human hepatoma cell line G2 (Hep G2) in the absence and the presence of interferon-gamma (IFN-gamma). E.l.i.s.a. performed on culture fluids, run-on transcription assays, Northern blot and double-dilution dot-blot techniques confirmed that monocytes expressed all six components, whereas fibroblasts, HUVEC and HepG2 each expressed five of the six components. Fibroblasts and HUVEC did not synthesize C4-bp, and Hep G2 did not produce factor H. In addition to these differences, the synthesis rates of C3, C1-inh and factor H were not the same in all cell types. However, the synthesis rates of C2 and factor B were similar in all four cell types. The half-lives of the mRNAs were shorter in monocytes than in other cell types. Monocyte factor H mRNA had a half-life of 12 min in monocytes, compared with over 3 h in fibroblasts and HUVEC. The instability of factor H mRNA in monocytes may contribute to their low factor H secretion rate. IFN-gamma produced dose-dependent stimulation of C2, factor B, C1-inh, C4-bp and factor H synthesis by all cell types expressing these proteins, but decreased C3 synthesis in all four cell types. Cell-specific differences in the response to IFN-gamma were observed. The increased rates of transcription of the C1-inh and factor H genes in HUVEC were greater than in other cell types, while the increased rate of transcription of the C2, factor B and C1-inh genes in Hep G2 cells was less than in other cell types. IFN-gamma did not affect the stability of C3, factor H or C4 bp mRNAs, but increased the stability of factor B and C1-inh mRNAs and decreased the stability of C2 mRNA. Although these changes occurred in all four cell types studied, the half-life of C1-inh mRNA in monocytes was increased almost 4-fold, whereas the increases in the other cell types were less than 30%. These data show that the constitutive synthesis rates of complement components may vary in the different cell types. They also show that the degree of change in synthesis rates in response to IFN-gamma in each of the cell types often varies due to differences in transcriptional response, sometimes in association with changes in mRNA stability.

Carrier Proteins↗