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Human Lymphocytes (human + lymphocyte)

Distribution by Scientific Domains
Life Sciences46%
Medical Sciences41%
Chemistry6%

Kinds of Human Lymphocytes

  • normal human lymphocyte
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    Selected Abstracts

    Effect of Bupleuri Radix Extracts on the Toxicity of 5-Fluorouracil in HepG2 Hepatoma Cells and Normal Human Lymphocytes

    BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2008
    Su Jin Kang
    We sought to assess whether Bupleuri Radix extract enhances 5-fluorouracil-induced cytotoxicity in HepG2 hepatoma cells, while protecting normal blood lymphocytes. Bupleuri Radix, used for treatment of liver disease in oriental medicine, possesses antitumour properties; it induces apoptosis through cell arrest in tumour cells, but does not affect normal lymphocytes. In this study, we evaluated the protective and enhancing effects of Bupleuri Radix on 5-fluorouracil-induced cytotoxicity in HepG2 cells and normal lymphocytes. Treatment with Bupleuri Radix increased the micronuclei frequency and DNA damage, resulting from 5-fluorouracil treatment. However, when human lymphocytes were cotreated with Bupleuri Radix and 5-fluorouracil, the frequency of 5-fluorouracil-induced micronuclei decreased. Although the extent of 5-fluorouracil-induced DNA damage, determined by single-cell gel electrophoresis, increased after treating HepG2 cells with Bupleuri Radix, it decreased in normal lymphocytes. When cells were treated with 20 µM 5-fluorouracil and 200 µg/ml Bupleuri Radix simultaneously, Bax protein increased in HepG2 cells at 24 hr; however, p21 and p53 proteins were up-regulated in normal human lymphocytes. Cotreatment with 200 µg/ml Bupleuri Radix and 20 µM 5-fluorouracil resulted in cell arrest at the late G1/early S phase in HepG2 cells (55.80 ± 0.19%) and normal lymphocytes (97.19 ± 0.27%). In addition, Bupleuri Radix and 5-fluorouracil treatment increased mitochondria membrane potential collapse only in HepG2 cells (19.02%), while it was not changed in lymphocytes. In conclusion, our findings suggest that Bupleuri Radix may be effective as a therapeutic agent to treat hepatomas. [source]

    Identification of a pre-S2 mutant in hepatocytes expressing a novel marginal pattern of surface antigen in advanced diseases of chronic hepatitis B virus infection

    JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 5 2000
    Yu-Fen Fan
    Abstract Background and Aims: The expression of hepatitis B viral (HBV) antigens in liver tissue reflects the replicative status of chronic HBV infection. We have previously recognized a novel marginal pattern of hepatitis B surface antigen (HBsAg) in hepatocytes, which usually clusters in groups and emerges at the late non-replicative phase. This study was designed to investigate whether the marginal-type HBsAg represented the gene product of a specific HBV-surface mutant. Methods: Microdissection of cirrhotic nodules homogeneously expressing marginal HBsAg was performed on two of 12 resected livers from HBsAg-seropositive patients with hepatocellular carcinoma. The gene presumably encoding marginal HBsAg was polymerase chain reaction (PCR)-cloned, sequenced and analysed. In vitro transfection and expression of the cloned surface mutant plasmids were performed on the Huh7 cell line to illustrate intrahepatic HBsAg expression. Results: Immunohistochemical staining revealed that the marginal HBsAg was positive for pre-S1 and thus contained large surface proteins. The PCR cloning and sequencing of the genes presumably encoding marginal-type HBsAg in both cases revealed the same deletion at the 5, terminus (nt 2,55) of pre-S2. A point mutation on the small-surface (S) antigen was also found in one case. The pre-S2 deletion sequence and the mutation sites of the S gene coincide with human lymphocyte antigen-restricted T- and/or B-cell epitopes. In vitro transfection of the mutant plasmid revealed a blot-like retention or accumulation of HBsAg in the cytoplasm or at the periphery of hepatocytes, accompanied by a decreased secretion of HBsAg in the culture supernatant, mimicking intrahepatic expression. Conclusion: A natural pre-S2 deletion mutant was identified in hepatocytes expressing a novel marginal pattern of HBsAg, which probably contains mutant, large, surface proteins. The biological significance of the pre-S2 deletion mutant should be interesting in view of the clustering proliferation of hepatocytes expressing marginal HBsAg. [source]

    Radioprotective effects of Daflon against genotoxicity induced by gamma irradiation in human cultured lymphocytes

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2009
    Seyed Jalal Hosseinimehr
    Abstract The ability of Daflon to protect against genotoxicity induced by gamma irradiation has been investigated in vivo and in vitro in cultured lymphocytes from healthy human volunteers. Peripheral human blood samples were collected predose (10 min before) and 1, 2, and 3 hr after a single oral ingestion of 1000 mg of Daflon. At each time point, whole blood was exposed in vitro to 150 cGy of cobalt-60 gamma rays, and then the lymphocytes were cultured with mitogenic stimulation to determine the micronuclei in cytokinesis-blocked binucleated cells. For each volunteer, the results showed a significant increase in the incidence of micronuclei after exposure to gamma irradiation as compared to control unexposed samples. As early as 1 hr after Daflon administration, a significant decrease in the incidence of micronuclei was observed in comparison with similarly irradiated lymphocytes collected before administration. The maximum protection was reached 1 hr after administration of Daflon with a significant decrease in the frequency of micronuclei of 40%. These findings suggest the possible application of Daflon for the protection of human lymphocytes from the genetic damage and side effects induced by gamma irradiation. Environ. Mol. Mutagen. 2009. © 2009 Wiley-Liss, Inc. [source]

    Influence of DNA repair gene polymorphisms on the initial repair of MMS-induced DNA damage in human lymphocytes as measured by the alkaline comet assay

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 9 2008
    Charlotta Ryk
    Abstract We have applied the alkaline comet assay to study the functional impact of gene polymorphisms in base excision repair (APEX1 Asp148Glu, XRCC1 Arg194Trp, XRCC1 Arg399Gln) and homologous recombination repair (XRCC3 Thr241Met, NBS1 Glu185Gln), two pathways that play crucial roles in the repair of DNA damage induced by methylmethane sulphonate (MMS). We also examined the effect of polymorphisms in mismatch repair (MLH1 ,93 A/G) and nucleotide excision repair (XPD Lys751Gln) as putative negative controls based on the limited roles of these pathways in MMS-induced repair. Phytohemagglutinin-stimulated peripheral lymphocytes from 52 healthy individuals were treated with MMS and allowed to repair for 0, 15, 40, or 120 min after a 6-min washing step. DNA damage was measured as a pseudo-percentage score (comparable to % tail DNA) converted from a total visual score calculated from the distribution of cells with different degrees of damage (normal, mild, moderate and severe). The repair was faster at the beginning of the observation period than towards the end, and was not complete after 2 hr. Presence of the APEX1 148Asp, XRCC3 241Met or NBS1 185Gln alleles were significantly associated with a high pseudo-percentage score (above median) at early time points, with the APEX1 effect being most prolonged (up to 40 min after washing, odds ratio 5.6, 95% confidence interval 2.0,15.5). No significant effects were seen with the XRCC1 Arg194Trp, XRCC1 Arg399Gln, MLH1 ,93A/G and XPD Lys751Gln polymorphisms. Our results provide evidence for the functional nature of the variant alleles studied in the APEX1, XRCC3, and NBS1 genes. Environ. Mol. Mutagen., 2008. © 2008 Wiley-Liss, Inc. [source]

    In vitro evaluation of the clastogenicity of fumagillin

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 8 2008
    Jevrosima Stevanovic
    Abstract Fumagillin, an antibiotic compound produced by Aspergillus fumigatus, is effective against microsporidia and various Amoeba species, but is also toxic when administered systemically to mammals. Furthermore, a recent in vivo study by Stanimirovic Z et al. 2007: (Mutat Res 628:1,10) indicated genotoxic effects of fumagillin. The aim of the present study was to investigate and explain the clastogenic effects of fumagillin (in the form of fumagillin dicyclohexylamine salt) on human peripheral blood lymphocytes in vitro by sister-chromatid exchanges (SCE), chromosome aberrations (CA), and micronucleus (MN) tests. The mitotic index (MI), proliferation index (PI), and nuclear division index (NDI) were calculated to evaluate the cytotoxic potential of fumagillin. Five concentrations of fumagillin (0.34, 0.68, 1.02, 3.07, and 9.20 ,g/ml) were applied to lymphocyte cultures. All the tested concentrations of fumagillin increased the frequency of SCE per cell significantly (P < 0.001 or P < 0.01) compared with the negative control. A significant (P < 0.001) increase in frequency of structural CA was observed at the three highest concentrations in comparison with the negative control. In addition, the three highest test concentrations increased MN formation and decreased MI, PI, and NDI significantly compared with the negative control. The present results indicate that fumagillin is clastogenic and cytotoxic to cultured human lymphocytes. Environ. Mol. Mutagen., 2008. © 2008 Wiley-Liss, Inc. [source]

    Cytogenetic effects of commercial formulations of deltamethrin and/or isoproturon on human peripheral lymphocytes and mouse bone marrow cells

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 8 2007
    Lalit K.S. Chauhan
    Abstract The cytogenetic effects of deltamethrin (DEL) and/or isoproturon (ISO) were examined in human lymphocytes and mouse bone marrow cells. Peripheral lymphocytes were exposed to DEL (2.5, 5, 10, or 20 ,M), ISO (25, 50, 100, or 200,M), or DEL + ISO (2.5 + 25, 5 + 50, 10 + 100, or 20 + 200 ,M) and cytogenic effects were evaluated via chromosomal aberrations (CA) and the cytokinesis-block micronucleus assay (CBMN). Mice were orally gavaged to single dose of DEL (6.6 mg/kg), ISO (670 mg/kg), or DEL+ISO (6.6 + 670 mg/kg) for 24 hr or to DEL (3.3 mg/kg/day), ISO (330 mg/kg/day), or DEL + ISO (3.3 + 330 mg/kg/day) for 30 days and analyzed for CA. DEL induced a significant frequency of CA at 10 ,M whereas ISO (25,100,M) alone, or in combination with DEL, did not show any significant effect. Micronucleus (MN) induction was observed to be concentration-dependent though significant frequencies were observed at 5 ,M DEL, 100 ,M ISO, or 5 + 50 ,M DEL + ISO. In mice, DEL inhibited the mitotic index (MI) significantly (P < 0.001) at 24 hr while ISO alone, or in combination with DEL, did not cause any statistically significant effect. Following a 24 hr exposure, DEL and ISO alone induced significant (P < 0.01) frequencies of CA, whereas DEL + ISO in combination did not. Furthermore, 30 days exposure of ISO significantly inhibited the MI (P < 0.02 or < 0.01) and induced CA while DEL alone, or in combination with ISO, resulted in no significant effect on CA or the MI. The present findings indicate that the in vitro and in vivo exposure of a commercial formulation of DEL can cause genotoxic effects in mammals. However, the coexposure of DEL and ISO did not show additive effects, but instead demonstrated somewhat reduced genotoxicity. Environ. Mol. Mutagen., 2007. © 2007 Wiley-Liss, Inc. [source]

    DNA damage assessment by comet assay of human lymphocytes exposed to jet propulsion fuels

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2002
    Shawna M. Jackman
    Abstract Exposure to jet fuel damages DNA and results in a number of physiological changes in liver, lung, immune, and neurological tissue. In this study the single-cell gel electrophoresis assay or comet assay was used to compare the DNA damage in human peripheral lymphocytes produced by three jet propulsion fuels: JP-8, JP-5, and JP-8+100. These fuels consist of complex mixtures of aliphatic, aromatic, and substituted naphthalene hydrocarbons. Two exposure times were investigated which correspond to estimated occupational exposure times and concentrations of fuels were used that were based on previous fuel toxicity studies. Analysis of samples for the extent of DNA damage as determined by tail moment and percent tail DNA was performed on exposed cells following a brief recovery time. All fuels produced significant increases in DNA damage; however, only JP-8+100 was genotoxic at the lowest exposure concentration (1:500). At the highest exposure concentration (1:75), the mean tail moments for JP-8 and JP-8+100 (32.041 ± 2.599 and 45.774 ± 4.743, respectively) were significantly greater than for JP-5 (1.314 ± 0.474). These results indicate that JP-8+100 is the most potent inducer of DNA damage in human peripheral lymphocytes and that both JP-8+100 and JP-8 are capable of damaging lymphocyte DNA to a greater extent than JP-5. Environ. Mol. Mutagen. 40:18,23, 2002. © 2002 Wiley-Liss, Inc. [source]

    Structure,activity analysis of the potentiation by aminothiols of the chromosome-damaging effect of bleomycin in G0 human lymphocytes

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2 2001
    George R. Hoffmann
    Abstract The radioprotective aminothiols 2-[(aminopropyl)amino] ethanethiol (WR-1065) and cysteamine (CSM) potentiate the induction of chromosomal damage by the radiomimetic compound bleomycin (BLM) in G0 human lymphocytes. To investigate the mechanism of potentiation, we measured the clastogenic activity of BLM in the cytokinesis-block micronucleus assay in the presence and absence of amines, thiols, and aminothiols. The hydroxy analog of WR-1065, 2-(3-aminopropylamino) ethanol (WR-OH), potentiates BLM only slightly, indicating the critical nature of the thiol group. As thiols, WR-1065 and CSM may donate electrons for the activation of Fe+2 -BLM or for the regeneration of Fe+2 -BLM from inactive Fe+3 -BLM. The amines putrescine, spermidine, and spermine all potentiate BLM, but they are weaker potentiators than the aminothiols, and they are effective only at high concentrations. Their activity, like that of WR-OH, is probably a consequence of conformational alteration of DNA. Dithioerythritol (DTE) and 2-mercaptoethanol (2-ME), thiols lacking an amino group, are less effective potentiators of BLM than are the aminothiols. The thiol group of WR-1065 and CSM is therefore essential, but insufficient, for explaining the strong enhancement of BLM activity. The cationic nature of CSM and WR-1065, conferred by the amino groups, evidently concentrates the active thiol function at the site of BLM action on DNA. As expected on this basis, the diamine WR-1065 is a more effective potentiator of BLM than is the monoamine CSM, whereas cysteine and N -acetylcysteine (NAC), which lack a net positive charge, potentiate BLM only weakly. These studies suggest that potentiation of the clastogenic action of BLM by aminothiols can be explained by the combination of a thiol-mediated redox mechanism and an amine-mediated targeting of the thiol function to DNA. Environ. Mol. Mutagen. 37:117,127, 2001 © 2001 Wiley-Liss, Inc. [source]

    Apoptotic effect of cyanobacterial extract on rat hepatocytes and human lymphocytes

    ENVIRONMENTAL TOXICOLOGY, Issue 3 2001
    Joanna Mankiewicz
    Abstract Toxic cyanobacterial blooms are an increasing problem in Poland. The production of cyanobacterial toxins and their presence in drinking and recreational waters represent a growing danger to human and animal health. This is connected with the increase of cyanobacterial biomass caused by excessive eutrophication of the water ecosystem. There is evidence that cyanobacterial hepatotoxins can act as a potent promoter of primary liver cancer. The apoptotic effect of microcystins in Polish cyanobacterial bloom samples on rat hepatocytes and human lymphocytes was observed using light and fluorescence microscopy, flow cytometry, and electrophoretic analysis. The incubation time needed to observe the first morphological apoptotic changes in hepatocytes was approximately 30 min; however, the characteristic biochemical changes in DNA were not observed even after 120 min. In lymphocyte cultures the morphological changes characteristic for apoptosis were observed after 24 h of incubation and a 48-h incubation was found to be optimal for analysis of internucleosomal DNA fragmentation, which is one of the main biochemical hallmarks of programmed cell death. These cells are an easily isolated and inexpensive material for medical diagnostics. Therefore the apoptotic changes, together with the clastogenic effect seen in lymphocyte cultures, are proposed as a future analytical method for these toxins. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 225,233, 2001 [source]

    Resveratrol modulates apoptosis and oxidation in human blood mononuclear cells

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2003
    G. A. Losa
    Abstract Background, We examined the effect of resveratrol (RS), a nonflavonoid polyphenolic phytoalexin found in grapes and red wine, and RS coincubated with the oxidant 2-deoxy-D-ribose (dR), on apoptosis and on the oxidative metabolic status of normal human peripheral blood mononuclear cells (PBMNCs) isolated ex vivo from healthy donors. Material and methods, Apoptosis was measured by changes of membrane permeability to propidium iodide (PI), plasma membrane exposure of phosphatidylserine (PS) and intracellular caspase activity. Oxidative status was assessed by recording the intracellular glutathione concentration (GSH), the activities of the enzymes y -glutamyltransferase (y- GT) and glutathione-S-transferase (GST), and intracellular lipid peroxidation (MDA). Results, Neither apoptotic nor oxidative parameters were affected by culturing PBMNCs in medium containing RS up to 20 µM for 5 days, while the frequency of cells with intermediate permeability to PI (17% ± 5) increased at 50 µM of RS. Thus resveratrol was slightly toxic, but there was little apoptosis in these cells. Peripheral blood mononuclear cells were also grown first in medium plus RS for 24 h and then for 96 h in medium containing RS plus 10 mM of dR, an oxidant sugar that is apoptogenic for human lymphocytes. The apoptotic changes triggered by dR were counteracted by the phytoalexin in a dose-dependent manner, but RS activity was absent at the lowest concentration (5 µM) and significantly reduced at the highest concentration used (50 µM). In PBMNCs coincubated with 20 µM of RS and 10 mM of dR the antioxidant effect of RS manifested with a significant reduction of caspases-3, -8, y- GT, GST activities and MDA content. Conclusions, Peripheral blood mononuclear cells acquire antioxidant capacity when treated with RS. Grape resveratrol may make a useful dietary supplement for minimizing oxidative injury in immune-perturbed states and human chronic degenerative diseases. [source]

    Up-regulation of leukocyte CXCR4 expression by sulfatide: An L-selectin-dependent pathway on CD4+ T cells

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2007
    Pascal Duchesneau
    Abstract CXCR4 plays significant roles in immune and inflammatory responses and is important for selective recruitment of leukocytes. We previously showed that CXCR4 surface expression of human lymphocytes was affected by sulfatide, an in vivo ligand for L-selectin. Increased CXCR4 expression was shown to promote biologically relevant functions such as integrin-dependent adhesion and transmigration. Here, we show that sulfatide-induced CXCR4 up-regulation also occurs on other leukocyte subsets in humans and mice. B cells and CD4+CD25+ T cells had the highest CXCR4 up-regulation after sulfatide stimulation. Transfection of L-selectin was sufficient for K562 cells to acquire sulfatide-induced CXCR4 up-regulation, while analysis of L-selectin knockout mice revealed that this response was critically L-selectin dependent only for CD4+ T cells, suggesting an alternative pathway in CD8+ T cells and B cells. Sulfatide triggered several intracellular signaling events in CD4+ T cells, but only tyrosine kinase activation, including members of the Src family, were essential for L-selectin to CXCR4 signaling. CXCR4 up-regulation was rapid, enhanced CXCL12-induced signaling and increased chemotaxis toward CXCL12, and therefore has potentially important roles in vivo. Thus, the response to CXCL12 depends in part on tissue expression of sulfatide and, specifically in CD4+ T cells, also depends on the surface level of L-selectin. [source]

    CD44 variant isoform v10 is expressed on tumor-infiltrating lymphocytes and mediates hyaluronan-independent heterotypic cell,cell adhesion to melanoma cells

    EXPERIMENTAL DERMATOLOGY, Issue 2 2003
    T. K. Weimann
    Abstract: CD44 is a family of cell-surface receptors on human lymphocytes that act as co-stimulatory molecules leading to the induction of effector functions in T cells. We have analyzed primary cutaneous malignant melanomas with clinical and histologic signs of tumor regression using immunohistochemistry and observed the predominant expression of the CD44 variant isoform v10 on CD3 CD4/CD8 co-expressing tumor-infiltrating lymphocytes (TIL). We further analyzed the role of CD44v10 in adhesion of lymphocytes to human melanoma cells. In contrast to CD44, lymphatic cells, CD44v10+ lymphatic cells strongly bound to cultured human melanoma cells and to frozen tissue samples of melanomas. Antibody blocking studies revealed a hyaluronan-, integrin-, and selectin-independent pathway of adhesion. Furthermore, CD44v10+ lymphatic cells exhibited significantly higher invasiveness in three-dimensional collagen matrices as compared with CD44H+ and CD44-negative lymphocytes. These results indicate that expression of CD44v10 on TIL may mediate adhesion to melanoma cells and result in gain of novel invasive properties. [source]

    Identification of different isoforms of eEF1A in the nuclear fraction of human T-lymphoblastic cancer cell line specifically binding to aptameric cytotoxic GT oligomers

    FEBS JOURNAL, Issue 15 2003
    Barbara Dapas
    GT oligomers, showing a dose-dependent cytotoxic effect on a variety of human cancer cell lines, but not on normal human lymphocytes, recognize and form complexes with nuclear proteins. By working with human T-lymphoblastic CCRF-CEM cells and by using MS and SouthWestern blotting, we identified eukaryotic elongation factor 1 alpha (eEF1A) as the main nuclear protein that specifically recognizes these oligonucleotides. Western blotting and supershift assays confirmed the nature of this protein and its involvement in forming a cytotoxicity-related complex (CRC). On the contrary, normal human lymphocytes did not show nuclear proteins able to produce CRC in a SouthWestern blot. Comparative bidimensional PAGE and Western-blotting analysis for eEF1A revealed the presence of a specific cluster of spots, focusing at more basic pH, in nuclear extracts of cancer cells but absent in those of normal lymphocytes. Moreover, a bidimensional PAGE SouthWestern blot demonstrated that cytotoxic GT oligomers selectively recognized the more basic eEF1A isoform expressed only in cancer cells. These results suggest the involvement of eEF1A, associated with the nuclear-enriched fraction, in the growth and maintenance of tumour cells, possibly modulated by post-translational processing of the polypeptide chain. [source]

    Identification of novel alternatively spliced BRCA1-associated RING domain (BARD1) messenger RNAs in human peripheral blood lymphocytes and in sporadic breast cancer tissues

    GENES, CHROMOSOMES AND CANCER, Issue 9 2007
    Grazia Lombardi
    BARD1 (BRCA1-associated RING domain) is the dominant binding partner of BRCA1 in vivo. The BARD1 gene has been reported to be mutated in a subset of breast and ovarian cancer patients and BARD1 germ-line mutations have been identified in breast cancer patients negative for BRCA1 or BRCA2 gene alterations. In the present study, we show by RT-PCR and direct sequencing analysis the occurrence of seven novel and one previously identified BARD1 splicing variants in human lymphocytes and breast cancers. Two of the eight variants (BARD1, and BARD1 ,RIN) preserve a correct open reading frame and could encode BARD1 internally deleted proteins, while the remaining six variants display premature stop codons. Characterization of the relative expression of BARD1 FL, BARD1,, and BARD1 ,RIN using quantitative PCR analysis indicated that the mean expression levels of BARD1 FL, BARD1,, and BARD1 ,RIN were significantly higher in tumors than in morphologically normal tissues and lymphocytes. However, we were unable to identify either qualitatively or quantitatively tumor-specific expression patterns of the identified BARD1 splicing variants. © 2007 Wiley-Liss, Inc. [source]

    Intrinsic genetic instability of normal human lymphocytes and its implication for loss of heterozygosity

    GENES, CHROMOSOMES AND CANCER, Issue 4 2001
    Arnolda G. de Nooij-van Dalen
    A combination of flow cytometry and microsatellite analysis was used to investigate loss of expression of HLA-A and/or HLA-B alleles and concurrent LOH at polymorphic chromosome 6 loci both in freshly isolated lymphocytes (in vivo mutations) and in lymphocytes cultured ex vivo. The fraction of in vivo mutants that showed LOH at 6p appeared to vary from 0%,49% for various donors. During culturing ex vivo, HLA-A, cells arose at a high rate and showed simultaneous loss of expression at the linked HLA-B locus. Up to 90% of the ex vivo arisen HLA-A2, cell population showed LOH of multiple 6p markers, and 50% had lost heterozygosity at 6q. This ex vivo spectrum resembles that found in HLA-A2 mutants obtained from lymphoblastoid cells. The HLA-A2 mutants present in vivo may reflect only a small fraction of the mutants that can be detected ex vivo. In normal lymphocytes, in vivo only mitotic recombination appears to be sustained, indicating the importance of this mechanism for tumor initiation in normal cells. Although mutations resulting in LOH at both chromosome 6 arms were shown to result in nonviable cells in normal lymphocytes, they have been shown to result in viable mutants in lymphoblastoid cells. We hypothesize that these types of mutations also occur in vivo but only survive in cells that already harbor a mutated genetic background. In light of the high rate at which these types of mutations occur, they may contribute to cancer progression. © 2001 Wiley-Liss, Inc. [source]

    Effects of human interleukin-18 and interleukin-12 treatment on human lymphocyte engraftment in NOD-scid mouse

    IMMUNOLOGY, Issue 2 2002
    Hidenobu Senpuku
    Summary NOD/LtSz- prkdcscid/prkdcscid (non-obese diabetic-severe combine immunodeficiency; NOD-scid) mice grafted with human peripheral blood lymphoid cells have been used as an in vivo humanized mouse model in various studies. However, cytotoxic human T cells are induced in this model during immune responses, which gives misleading results. To assist in grafting of human lymphocytes without the induction of cytotoxic human T cells, we investigated the effects of T helper type 1 (Th1) and Th2 cytokines on human lymphocyte grafting and migration, as well as the production of immunoglobulin deposited in glomeruli and human immunodeficiency virus-1 (HIV-1) infection using NOD-scid mice. Administration of interleukin-18 (IL-18) and IL-12 enhanced the grafting of human CD4+ and CD8+ T cells in the mice, whereas co-administration prevented grafting due to interferon-,-dependent apoptosis. Immunoglobulin A (IgA) deposits were observed in mice treated with IL-18 alone, but not in those given phosphate-buffered saline, IL-12 alone, or IL-18 + IL-12. A high rate of HIV infection was also observed in the IL-18-treated group. Together, these results indicate that IL-18 may be effective for the grafting and migration of CD4+ and CD8+ T cells, except for the induction of apoptosis and regulation of class-switching IgA. IL-18-administered NOD-scid mice provide a useful small humanized model for the study of HIV infection and IgA nephropathy. [source]

    Examination of cytotoxicity and mutagenicity of AH26 and AH Plus sealers

    INTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2003
    I. Mileti
    Abstract Aim ,To study in vitro the cytotoxic and mutagenic effects of AH26 and AH Plus. Methodology ,Cytotoxic effects on Chinese hamster V79 cells were determined by counting viable cells following incubation with eluations of AH26 and AH Plus. In one set of experiments, the materials were mixed, set for 1 h and then eluted with dimethyl sulphoxide (DMSO) for 1 h, 24 h and 7 days. In the other set, AH26 and AH Plus were mixed and set for 1 h, 24 h and 7 days in physiological saline then crushed and eluted in DMSO for 24 h. The cytotoxic effects of these eluates were evaluated. Three concentrations were chosen to examine the mutagenic effects of AH26 and AH Plus: 5.57, 16.7 and 55.7 ,g mL,1. The structural chromosomal aberration analysis and micronucleus test were performed on human lymphocytes according to standard procedures. Results ,Dose,response curves of cell survival were obtained. Both materials were shown to be cytotoxic in doses larger than 55.7 ,g mL,1, except for AH26, after 7 days setting time. AH Plus was also shown to be toxic in concentrations of 16.7 ,g mL,1, except after 7 days setting time. Neither AH26 nor AH Plus induced a significant increase of chromosomal aberrations or micronuclei induction at any setting time or concentration. Conclusion ,There was no mutagenicity found for AH26 and AH Plus on human lymphocytes in highly controlled conditions in vitro. [source]

    Evaluation of cytogenetic effects of lambda-cyhalothrin on human lymphocytes

    JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 5 2005
    Rambabu Naravaneni
    Abstract The genotoxic and cytotoxic potential of lambda-cyhalothrin (LCT), a synthetic pyrethroid insecticide, was investigated on human lymphocytes cultured in vitro. Utilizing the trypan blue dye exclusion technique assay, the LC50 of LCT was found to be 28 , M. Based on the LC50 value, it is seen that LCT was highly toxic to lymphocyte cultures, among other pyrethroid group of pesticides. Chromosomal aberrations induced by LCT were determined using metaphase plate-spreads of lymphocytes. The chromosomal analysis was recorded using Medi-Image software technology. The analysis revealed that more satellite associations and gaps were found, which were statistically significant (p < 0.05) when compared to controls. Comet assay was used to assess the possibility of LCT to induce the damage in DNA, where the increase in comet tail length relates to the extent of DNA single strand breaks. The results presented here indicate that in vitro assays could be used as indicators of cytotoxicity and genotoxicity of the pesticide. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:304,310, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20095 [source]

    Use of the 1-mm micro-probe for metabolic analysis on small volume biological samples

    JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009
    Natalie J. Serkova
    Abstract Endogenous metabolites are promising diagnostic end-points in cancer research. Clinical application of high-resolution NMR spectroscopy is often limited by extremely low volumes of human specimens. In the present study, the use of the Bruker 1-mm high-resolution TXI micro-probe was evaluated in the elucidation of metabolic profiles for three different clinical applications with limited sample sizes (body fluids, isolated cells and tissue biopsies). Sample preparation and 1H-NMR metabolite quantification protocols were optimized for following oncology-oriented applications: (i) to validate the absolute concentrations of citrate and spermine in human expressed prostatic specimens (EPS volumes 5 to 10 ,l: prostate cancer application); (ii) to establish the metabolic profile of isolated human lymphocytes (total cell count 4 = 106: chronic myelogenous leukaemia application); (iii) to assess the metabolic composition of human head-and-neck cancers from mouse xenografts (biopsy weights 20 to 70 mg: anti-cancer treatment application). In this study, the use of the Bruker 1-mm micro-probe provides a convenient way to measure and quantify endogenous metabolic profiles of samples with a very low volume/weight/cell count. [source]

    Microarray analysis of transcription factor gene expression in melatonin-treated human peripheral blood mononuclear cells

    JOURNAL OF PINEAL RESEARCH, Issue 4 2006
    Eunyoung Ha
    Abstract:, The existence of specific melatonin-binding sites in lymphoid cells led to the discovery of signal transduction pathway for melatonin in human lymphocytes and immunomodulatory role of melatonin in immune cells. In recent years, transcriptional regulation of melatonin on various transcription factors has been demonstrated. Therefore, this study was designed to assess by cDNA microarray analysis the regulatory effects of melatonin on transcription factors in human peripheral blood mononuclear cells (PBMCs). Forty-six genes were upregulated and 23 were downregulated more than twofold in melatonin-treated PBMCs. Of the more than twofold upregulated transcription factor genes, homeo box A4 (HOXA4), forkhead box O1A (FOXO1A), transcription elongation factor B (SIII), polypeptide 3 (TCEB3), and peroxisome proliferative activated receptor delta (PPARD) were identified. Of the more than twofold downregulated genes, PHD finger protein 15 (PHF15) and zinc finger protein 33a (ZNF33A) were identified. In summary, identification of these genes by cDNA microarray analysis in response to melatonin administration may provide a foundation for further studies on the function of melatonin in human PBMCs. [source]

    Desflurane anaesthesia increases sister chromatid exchange in human lymphocytes

    ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2006
    A. Akin
    No abstract is available for this article. [source]

    Treponema denticola immunoinhibitory protein induces irreversible G1 arrest in activated human lymphocytes

    MOLECULAR ORAL MICROBIOLOGY, Issue 3 2004
    W. Lee
    Oral spirochetes may contribute to the pathogenesis of a number of disorders including periodontal and periradicular diseases; however, the mechanism (s) by which these organisms act to cause disease is unknown. We have previously shown that extracts of the oral spirochete, Treponema denticola, contain an immunosuppressive protein (Sip) which impairs human lymphocyte proliferation. The objective of this study was to determine the mechanism by which Sip alters the proliferative response of lymphocytes. Human T-cells were activated by PHA in the presence or absence of Sip and cell cycle progression was assessed by flow cytometry. Cell cycle distribution was based upon DNA, RNA and protein content as well as expression of the activation markers; CD69 and IL-2R. Seventy-two hours following activation with PHA, cells were found in the G0, G1, S and G2/M phases of the cell cycle. In contrast, pretreatment with Sip resulted in a significant reduction of cells in the S and G2/M phases and a concomitant increase in the G1 phase. Sip did not alter the expression of the early activation markers CD69 and CD25R. To determine if G1 arrest resulted in activation of the checkpoint and cell death, we also monitored Sip-treated cells for apoptosis. Indeed, treatment with Sip resulted in both DNA fragmentation and caspase activation after 96 h. Our results indicate that Sip induces G1 arrest in human T-cells and, furthermore, that the arrest is irreversible, culminating in activation of the apoptotic cascade. We propose that if cell cycle arrest occurs in vivo, it may result in local and/or systemic immunosuppression and thereby enhance the pathogenicity of spirochetes and/or that of other opportunistic organisms. [source]

    Voltage-activated proton currents in human lymphocytes

    THE JOURNAL OF PHYSIOLOGY, Issue 1 2002
    Tom Schilling
    Voltage-activated proton currents are reported for the first time in human peripheral blood T and B lymphocytes and in the human leukaemic T cell line Jurkat E6-1. The properties of H+ currents studied using tight-seal voltage-clamp recording techniques were similar in all cells. Changing the pH gradient by one unit caused a 47 mV shift in the reversal potential, demonstrating high selectivity of the channels for protons. H+ current activation upon membrane depolarisation had a sigmoidal time course that could be fitted by a single exponential function after a brief delay. Increasing pHo shifted the activation threshold to more negative potentials, and increased both the H+ current amplitude and the rate of activation. In lymphocytes studied at pHi 6.0, the activation threshold was more negative and the H+ current density was three times larger than at pHi 7.0. Increasing the intracellular Ca2+ concentration to 1 ,m did not change H+ current amplitude or kinetics detectably. Extracellularly applied Zn2+ and Cd2+ inhibited proton currents, slowing activation and shifting the voltage-activation curve to more positive potentials. The H+ current amplitude was 100 times larger in CD19+ B lymphocytes and in Jurkat E6-1 cells than in CD3+ T lymphocytes. Following stimulation with the phorbol ester PMA, the H+ current density in peripheral blood T lymphocytes and Jurkat T cells increased. In contrast, the H+ current density of phorbol ester (PMA)-stimulated B lymphocytes was reduced and activation became slower. The pattern of expression of H+ channels in lymphocytes appears well suited to their proposed role of charge compensation during the respiratory burst. [source]

    Complex nature of the human antisperm antibody response in SCID mice

    ANDROLOGIA, Issue 2 2004
    M. Kurpisz
    Summary. Human peripheral blood mononuclear (PBMs) cells were introduced into the peritoneal cavity of severely-combined immunodeficient (SCID) mice in concentrations of 2.5,4.0 × 107 cells per mouse. Whole mononuclear cell suspensions were used either unstimulated or following primary in vitro culture with human spermatozoa. In some experiments, immunodepletion of CD8+ cells was carried out prior to grafting. Lymphocytes were obtained from nonsensitized (to antigen) human subjects or from individuals who were primed in vivo (vasectomized individuals in case of sperm antigens). An enzyme-linked immunosorbent assay was employed to assess total human immunoglobulin (G or M) levels as well as the specificity of the antibodies generated. We have been successful by generating primary and secondary immune responses with ,naïve' human lymphocytes, challenged with chlamydia or ovalbumin but without adjuvant or CD8+ immunodepletion; however, we were unable to induce specific antibodies to spermatozoa under this regime in SCID male mice. We then employed female SCID mice, treated with sperm antigen extracts (glycosylated or deglycosylated) encapsulated in liposomes and human lymphocytes obtained from ,naïve' or pre-sensitized in vivo subjects. It was found that the most pronounced humoral response to sperm antigens was obtained with deglycosylated antigens and PBMs from vasectomized (in vivo pre-primed to spermatozoa) individuals. A presented SCID mice model can be helpful at understanding of antisperm antibody development and the molecular nature of generated antibodies to modified sperm antigenic entities. [source]

    Erythropoietin Receptor Is Expressed on Human Peripheral Blood T and B Lymphocytes and Monocytes and Is Modulated by Recombinant Human Erythropoietin Treatment

    ARTIFICIAL ORGANS, Issue 8 2010
    Katarzyna A. Lisowska
    Abstract Erythropoietin receptor (EPO-R) appears on the cell surface in the early stages of erythropoiesis. It has also been found on endothelial cells and polymorphonuclear leukocytes, suggesting erythropoietin (EPO) role beyond erythropoiesis itself. Earlier reports have shown that treatment with recombinant human erythropoietin (rhEPO) in chronic renal failure (CRF) patients improves interleukin-2 production and restores the T lymphocyte function. We decided to investigate possible expression of EPO-R on circulating peripheral blood lymphocytes and monocytes of CRF patients in order to assess the possibility of rhEPO direct action on these cells. Flow cytometry was used for detection and quantification of EPO-R, and reverse transcription polymerase chain reaction for detection of the EPO receptor mRNA. Our results show for the first time the existence of EPO-R on cell surface of human T and B lymphocytes and monocytes as well as at the transcriptional activity of the EPO-R gene in these cells, both in healthy and CRF individuals. We have also found significant differences between the numbers of EPO-R molecules on T and B lymphocytes of CRF patients not treated and treated with rhEPO and healthy control. Discovery of EPO-R expression on human lymphocytes suggests that EPO is probably able to directly modulate some signaling pathways important for these cells. [source]

    Effect of Bupleuri Radix Extracts on the Toxicity of 5-Fluorouracil in HepG2 Hepatoma Cells and Normal Human Lymphocytes

    BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2008
    Su Jin Kang
    We sought to assess whether Bupleuri Radix extract enhances 5-fluorouracil-induced cytotoxicity in HepG2 hepatoma cells, while protecting normal blood lymphocytes. Bupleuri Radix, used for treatment of liver disease in oriental medicine, possesses antitumour properties; it induces apoptosis through cell arrest in tumour cells, but does not affect normal lymphocytes. In this study, we evaluated the protective and enhancing effects of Bupleuri Radix on 5-fluorouracil-induced cytotoxicity in HepG2 cells and normal lymphocytes. Treatment with Bupleuri Radix increased the micronuclei frequency and DNA damage, resulting from 5-fluorouracil treatment. However, when human lymphocytes were cotreated with Bupleuri Radix and 5-fluorouracil, the frequency of 5-fluorouracil-induced micronuclei decreased. Although the extent of 5-fluorouracil-induced DNA damage, determined by single-cell gel electrophoresis, increased after treating HepG2 cells with Bupleuri Radix, it decreased in normal lymphocytes. When cells were treated with 20 µM 5-fluorouracil and 200 µg/ml Bupleuri Radix simultaneously, Bax protein increased in HepG2 cells at 24 hr; however, p21 and p53 proteins were up-regulated in normal human lymphocytes. Cotreatment with 200 µg/ml Bupleuri Radix and 20 µM 5-fluorouracil resulted in cell arrest at the late G1/early S phase in HepG2 cells (55.80 ± 0.19%) and normal lymphocytes (97.19 ± 0.27%). In addition, Bupleuri Radix and 5-fluorouracil treatment increased mitochondria membrane potential collapse only in HepG2 cells (19.02%), while it was not changed in lymphocytes. In conclusion, our findings suggest that Bupleuri Radix may be effective as a therapeutic agent to treat hepatomas. [source]

    Evaluation of genotoxic effects in human leukocytes after in vitro exposure to 1950 MHz UMTS radiofrequency field

    BIOELECTROMAGNETICS, Issue 3 2008
    O. Zeni
    Abstract In the present study the third generation wireless technology of the Universal Mobile Telecommunication System (UMTS) signal was investigated for the induction of genotoxic effects in human leukocytes. Peripheral blood from six healthy donors was used and, for each donor, intermittent exposures (6 min RF on, 2 h RF off) at the frequency of 1950 MHz were conducted at a specific absorption rate of 2.2 W/kg. The exposures were performed in a transverse electro magnetic (TEM) cell hosted in an incubator under strictly controlled conditions of temperature and dosimetry. Following long duration intermittent RF exposures (from 24 to 68 h) in different stages of the cell cycle, micronucleus formation was evaluated by applying the cytokinesis block micronucleus assay, which also provides information on cell division kinetics. Primary DNA damage (strand breaks/alkali labile sites) was also investigated following 24 h of intermittent RF exposures, by applying the alkaline single cell gel electrophoresis (SCG)/comet assay. Positive controls were included by treating cell cultures with Mitomycin-C and methylmethanesulfonate for micronucleus and comet assays, respectively. The results obtained indicate that intermittent exposures of human lymphocytes in different stages of cell cycle do not induce either an increase in micronucleated cells, or change in cell cycle kinetics; moreover, 24 h intermittent exposures also fail to affect DNA structure of human leukocytes soon after the exposures, likely indicating that repairable DNA damage was not induced. Bioelectromagnetics 29:177,184, 2008. © 2007 Wiley-Liss, Inc. [source]

    915 MHz microwaves and 50 Hz magnetic field affect chromatin conformation and 53BP1 foci in human lymphocytes from hypersensitive and healthy persons

    BIOELECTROMAGNETICS, Issue 3 2005
    Igor Y. Belyaev
    Abstract We used exposure to microwaves from a global system for mobile communication (GSM) mobile phone (915 MHz, specific absorption rate (SAR) 37 mW/kg) and power frequency magnetic field (50 Hz, 15 ,T peak value) to investigate the response of lymphocytes from healthy subjects and from persons reporting hypersensitivity to electromagnetic field (EMF). The hypersensitive and healthy donors were matched by gender and age and the data were analyzed blind to treatment condition. The changes in chromatin conformation were measured with the method of anomalous viscosity time dependencies (AVTD). 53BP1 protein, which has been shown to colocalize in foci with DNA double strand breaks (DSBs), was analyzed by immunostaining in situ. Exposure at room temperature to either 915 MHz or 50 Hz resulted in significant condensation of chromatin, shown as AVTD changes, which was similar to the effect of heat shock at 41 °C. No significant differences in responses between normal and hypersensitive subjects were detected. Neither 915 MHz nor 50 Hz exposure induced 53BP1 foci. On the contrary, a distinct decrease in background level of 53BP1 signaling was observed upon these exposures as well as after heat shock treatments. This decrease correlated with the AVTD data and may indicate decrease in accessibility of 53BP1 to antibodies because of stress-induced chromatin condensation. Apoptosis was determined by morphological changes and by apoptotic fragmentation of DNA as analyzed by pulsed-field gel electrophoresis (PFGE). No apoptosis was induced by exposure to 50 Hz and 915 MHz microwaves. In conclusion, 50 Hz magnetic field and 915 MHz microwaves under specified conditions of exposure induced comparable responses in lymphocytes from healthy and hypersensitive donors that were similar but not identical to stress response induced by heat shock. Bioelectromagnetics 26:173,184, 2005. © 2005 Wiley-Liss, Inc. [source]

    Differences in lethality between cancer cells and human lymphocytes caused by LF-electromagnetic fields

    BIOELECTROMAGNETICS, Issue 7 2004
    Maria Radeva
    Abstract The lethal response of cultured cancer cells lines K-562, U-937, DG-75, and HL-60 were measured directly after a 4 h exposure to a pulsating electromagnetic field (PEMF, sinusoidal wave form, 35 mT peak, 50 Hz) [Traitcheva et al. (2003): Bioelectromagnetics 24:148,158] and 24 h later, to determine the post-exposure effect. The results were found to depend on the medium, pH value, conductivity, and temperature. From these experiments, suitable conditions were chosen to compare the vitality between K-562 cells and normal human lymphocytes after PEMF treatment and photodynamic action. Both agents enhance necrosis synergistically for diseased as well as for healthy cells, but the lymphocytes are more resistant. The efficacy of PEMF on the destruction of cancer cells is further increased by heating (hyperthermia) of the suspension up to 44 °C or by lowering the pH-value (hyperacidity) to pH 6.4. Similar apoptosis and necrosis can be obtained using moderate magnetic fields (B,,,15 mT 50/60 Hz), but this requires longer treatment of at least over a week. PEMF application combined with anticancer drugs and photodynamic therapy will be very effective. Bioelectromagnetics 25:503,507, 2004. © 2004 Wiley-Liss, Inc. [source]

    The effect of exposure to high flux density static and pulsed magnetic fields on lymphocyte function

    BIOELECTROMAGNETICS, Issue 6 2003
    Carlo Aldinucci
    Abstract We investigated whether a combination of static electromagnetic field (EMF) at a flux density of 4.75 T together with pulsed EMF at a flux density of 0.7 mT generated by an NMR apparatus (NMRF), could promote movements of Ca2+, cell proliferation, and the eventual production of proinflammatory cytokines in human lymphocytes as well as in Jurkat cells, after exposure to the field for 1 h. The same study was also performed after activation of cells with 5 ,g/ml phytohaemagglutinin (PHA) immediately before the exposure period. Our results clearly demonstrate that NMRF exposure increases the [Ca2+]i, without any proliferative, or activating, or proinflammatory effect on both normal and PHA stimulated lymphocytes. Accordingly, the levels of interferon ,, tumor necrosis factor ,, interleukin-1,, interleukin-2, and interleukin-6 remained unvaried after exposure. Exposure of Jurkat cells statistically decreased the [Ca2+]i and the proliferation. This is consistent with the low levels of IL-2 measured in supernatants of these cells after exposure. On the whole our data suggest that static and pulsed NMRF exposure contribute synergistically in the increase of the [Ca2+]i without any activating or proinflammatory effect either in normal or in PHA challenged lymphocytes. In Jurkat cells, by changing the properties of cell membranes, NMRF exposure can influence Ca2+ transport processes and hence Ca2+ homeostasis, causing a marked decrease of proliferation. Bioelectromagnetics 24:373,379, 2003. © 2003 Wiley-Liss, Inc. [source]