HELVETICA CHIMICA ACTA, Issue 8 2009
Ya-Na Shi
Abstract The phytochemical investigation of Dipteronia dyeriana (Aceraceae) resulted in the isolation and identification of three new cycloheximide derivatives: dipteronines A,C (1,3). Their structures were elucidated based on the 1D- and 2D-NMR spectra. Dipteronine A (1) is the first example of a 10,11-secocycloheximide. Cytotoxic and antifungal activities of these isolates were also evaluated. [source]

Cytotoxic and antimitotic effects of N -containing Monascus metabolites studied using immortalized human kidney epithelial cells

MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 4-5 2006
Anja Knecht
Abstract Recently the first Monascus metabolites with a pyridine ring were detected, the monascopyridines A and B. They are formally dehydrogenated derivatives of the red rice pigments rubropunctamine and monascorubramine. Because of their structural similarity, the toxicological effects of these secondary metabolites were studied using immortalized human kidney epithelial cells. The cytotoxicity was determined with the following different endpoint detection methods: metabolic activity, trypan blue exclusion, and electronic cell counting. The compounds led to EC50 values between 11 and 31 ,mol/L but the pigments caused a stronger reduction of the cell viability. Also, the apoptotic potential was examined by measuring caspase 3 activity and detecting apoptotic bodies, but none of the tested compounds induced apoptosis. All four substances caused a rise of the mitotic index to about 9% (100 ,mol/L monascopyridine A and B) and 20% (25 ,mol/L rubropunctamine and monascorubramine). The significant decrease of the ratio of cells in the ana- and telophase to cells in the prometa- and metaphase proved a stop of the mitosis at the meta- to anaphase control point. The compounds caused mitotic arrest and the formation of structural damages like c-mitosis through interaction with the mitotic spindle. These effects point to an aneuploidy inducing potential, which is linked to cancer formation. [source]

Evaluation of Cytotoxic and Cytostatic Effects in Saccharomyces cerevisiae by Poissoner Quantitative Drop Test

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 1 2009
Nadine Paese Poletto
Current assay techniques, however, typically require the use of expensive technological equipment or chemical reagents, or they lack adequate testing sensitivity. The poissoner quantitative drop test (PQDT) assay is a sensitive, inexpensive and accurate method for evaluation of cytotoxicity and/or cytostatic effects of multiple chemical compounds in a single experiment. In this study, the sensitivity of the PQDT assay was evaluated in a wild-type Saccharomyces cerevisiae strain using 4-nitroquinoline-N - oxide (4-NQO) and methyl methanesulfonate (MMS), both cytotoxic and genotoxic standard compounds, and cytostatic 5-fluorouracil, an antitumoral drug. Yeast cell colony growth was measured in culture media containing increasing concentrations of the three chemical agents. The results showed that the PQDT assay was able to clearly differentiate the cytotoxic effect of 4-NQO and MMS from the cytostatic effect of 5-fluorouracil. Interestingly, the cytostatic effect of 5-fluorouracil followed an exponential decay curve with increasing concentrations, a phenomenon not previously described for this drug. The PQDT assay, in this sense, can be applied not only for cytotoxic/cytostatic assays, but also for pharmacodynamic studies using Saccharomyces cerevisiae as a model. [source]

ChemInform Abstract: Synthesis of Novel 4,6-Disubstituted Quinazoline Derivatives, Their Antiinflammatory and Anticancer Activity (Cytotoxic) Against U937 Leukemia Cell Lines.

CHEMINFORM, Issue 35 2008
P. Mani Chandrika
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Facile Synthesis of Active Antitubercular, Cytotoxic and Antibacterial Agents: A Michael Addition Approach.

CHEMINFORM, Issue 9 2006
Madhukar S. Chande
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Cytotoxic,Antineoplastic Activity of Acetyl Derivatives of Prenylnaphthohydroquinone.

CHEMINFORM, Issue 46 2004
Aurora Molinari
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Regioselective Synthesis of Cytotoxic 4-(1-Alkynyl)-Substituted 2-(5H)-Furanones.

CHEMINFORM, Issue 9 2004
Fabio Bellina
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Synthesis and Biological Evaluation of Cytotoxic 6(7)-Alkyl-2-hydroxy-1,4-naphthoquinones.

CHEMINFORM, Issue 13 2003
Jose M. Miguel del Corral
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

ChemInform Abstract: Syntheses and Cytotoxic, Antimicrobial, Antifungal, and Cardiovascular Activity of New Quinoline Derivatives.

CHEMINFORM, Issue 4 2001
Kalid Mohammed Khan
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

A Photoactivated trans -Diammine Platinum Complex as Cytotoxic as Cisplatin

CHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2006
Fiona S. Mackay
Abstract The synthesis and X-ray structure (as the tetrahydrate) of the platinum(IV) complex trans,trans,trans -[Pt(N3)2(OH)2(NH3)2] 3 are described and its photochemistry and photobiology are compared with those of the cis isomer cis,trans,cis -[Pt(N3)2(OH)2(NH3)2] 4. Complexes 4 and 3 are potential precursors of the anticancer drug cisplatin and its inactive trans isomer transplatin, respectively. The trans complex 3 is octahedral, contains almost linear azide ligands, and adopts a layer structure with extensive intermolecular hydrogen bonding. The intense azide-to-platinum(IV) charge-transfer band of complex 3 (285 nm; ,=19,500,M,1,cm,1) is more intense and bathochromically shifted relative to that of the cis isomer 4. In contrast to transplatin, complex 3 rapidly formed a platinum(II) bis(5,-guanosine monophosphate) (5,-GMP) adduct when irradiated with UVA light, and did not react in the dark. Complexes 3 and 4 were non-toxic to human skin cells (keratinocytes) in the dark, but were as cytotoxic as cisplatin on irradiation for a short time (50 min). Damage to the DNA of these cells was detected by using the "comet" assay. Both trans- and cis -diammine platinum(IV) diazide complexes therefore have potential as photochemotherapeutic agents. [source]

Water-soluble Organometallic Analogues of Oxaliplatin with Cytotoxic and Anticlonogenic Activity

CHEMMEDCHEM, Issue 1 2010
Michele Benedetti Dr.
Pt prodrugs: We synthesized new cationic complexes [PtCl(,2 -C2H4)(R,R -chxn)]Cl (1) and [PtCl(,2 -C2H4)(S,S -chxn)]Cl (2), which are organometallic analogues of the drug oxaliplatin. Complexes 1 and 2 can be considered antitumor prodrugs, as we demonstrate that they can decompose to give the same metabolites as those of oxaliplatin. [source]

Allergic contact dermatitis: the cellular effectors

CONTACT DERMATITIS, Issue 1 2002
Ian Kimber
Contact hypersensitivity reactions are mediated by lymphocytic effector cells. Until recently it was believed that the most important of these were CD4+ T lymphocytes. However, there is growing evidence that in many instances the predominant effector cell may be a CD8+ T lymphocyte, with in some instances CD4+ cells performing a counter-regulatory function. Here we review the roles of CD4+ T helper (Th) cells and CD8+ T cytotoxic (Tc) cells, and their main functional subpopulations (respectively, Th1 and Th2 cells and Tc1 and Tc2 cells) in the elicitation of contact hypersensitivity reactions and consider the implications of effector cell selectivity for the biology of allergic contact dermatitis. [source]

Influence of hormones and hormone metabolites on the growth of schwann cells derived from embryonic stem cells and on tumor cell lines expressing variable levels of neurofibromin,

DEVELOPMENTAL DYNAMICS, Issue 2 2008
Therese M. Roth
Abstract Loss of neurofibromin, the protein product of the tumor suppressor gene neurofibromatosis type 1 (NF1), is associated with neurofibromas, composed largely of Schwann cells. The number and size of neurofibromas in NF1 patients have been shown to increase during pregnancy. A mouse embryonic stem cell (mESC) model was used, in which mESCs with varying levels of neurofibromin were differentiated into Schwann-like cells. NF1 cell lines derived from a malignant and a benign human tumor were used to study proliferation in response to hormones. Estrogen and androgen receptors were not expressed or expressed at very low levels in the NF1+/+ cells, at low levels in NF1+/,cells, and robust levels in NF1,/,cells. A 17,-estradiol (E2) metabolite, 2-methoxy estradiol (2ME2) is cytotoxic to the NF1,/, malignant tumor cell line, and inhibits proliferation in the other cell lines. 2ME2 or its derivatives could provide new treatment avenues for NF1 hormone-sensitive tumors at times of greatet hormonal influence. Developmental Dynamics 237:513,524, 2008. © 2008 Wiley-Liss, Inc. [source]

Survival of mammalian B104 cells following neurite transection at different locations depends on somal Ca2+ concentration

DEVELOPMENTAL NEUROBIOLOGY, Issue 2 2004
Soonmoon Yoo
Abstract We report that cell survival after neurite transection in a mammalian neuronal model (cultured B104 cells) critically depends on somal [Ca2+]i, a novel result that reconciles separate long-standing observations that somal survival decreases with more-proximal axonal transections and that increased somal Ca2+ is cytotoxic. Using fluorescence microscopy, we demonstrate that extracellular Ca2+ at the site of plasmalemmal transection is necessary to form a plasmalemmal barrier, and that other divalent ions (Ba2+, Mg2+) do not play a major role. We also show that extracellular Ca2+, rather than injury per se, initiates the formation of a plasmalemmal barrier and that a transient increase in somal [Ca2+]i significantly decreases the percentage of cells that survive neurite transection. Furthermore, we show that the increased somal [Ca2+]i and decreased cell survival following proximal transections are not due to less frequent or slower plasmalemmal sealing or Ca2+ entry through plasmalemmal Na+ and Ca2+ channels. Rather, the increased somal [Ca2+]i and lethality of proximal neurite injuries may be due to the decreased path length/increased diameter for Ca2+ entering the transection site to reach the soma. A ryanodine block of Ca2+ release from internal stores before transection has no effect on cell survival; however, a ryanodine- or thapsigargin-induced buildup of somal [Ca2+]i before transection markedly reduces cell survival, suggesting a minor involvement of Ca2+ -induced release from internal stores. Finally, we show that cell survival following proximal injuries can be enhanced by increasing intracellular Ca2+ buffering capacity with BAPTA to prevent the increase in somal [Ca2+]i. © 2004 Wiley Periodicals, Inc. J Neurobiol 60: 137,153, 2004 [source]

Hydrophobic derivatives of 5-(hydroxymethyl)isophthalic acid that selectively induce apoptosis in leukemia cells but not in fibroblasts,,

DRUG DEVELOPMENT RESEARCH, Issue 4 2008
Anna Galkin
Abstract New apoptosis modulating agents are widely sought, because failure in regulation of apoptosis is associated with many diseases. In this study, we have evaluated apoptosis inducing the potential of ten new hydrophobic derivatives of 5-(hydroxymethyl)isophthalic acid. Cancerous leukemia cells (HL-60) and non-malignant fibroblasts (Swiss 3T3) were incubated with test compounds for 24,h and morphologically evaluated. The changes in mitochondrial membrane potential (,,m) and caspase-3 activity were used to confirm the results and to study early induction of apoptosis. Cytotoxicity was determined using the lactate dehydrogenase (LDH) assay and mutagenicity with miniaturized Ames-test. The most potent selective apoptosis inducers were compounds 1c and 1,h having IC50 values of 41 and 23,µM, respectively, in leukemia cells (HL-60) while effects in fibroblasts (Swiss 3T3) were insignificant. Reduction of ,,m and increase in caspase-3 activity were observed already during the first 2,hr in the HL-60 cells treated with compounds 1,c and 1,h. Neither of the compounds was cytotoxic or mutagenic. The results indicate that compounds 1,c and 1,h are selective apoptosis inducers and should be studied further for possible use in cancer therapy. Drug Dev. Res. 69: 185,195, 2008. © 2008 Wiley-Liss, Inc. [source]

Cytotoxicity of doxorubicin-loaded Con A-liposomes

DRUG DEVELOPMENT RESEARCH, Issue 5 2006
Hercília Maria Lins Rolim Santos
Abstract The present study investigated the potential of Concanavalin A lectin (Con A) conjugated to liposomes (Con A-liposomes) for targeting doxorubicin (DOX) to cells. The physicochemical properties and the cytotoxicity of DOX-loaded Con A-liposomes were evaluated. DOX-loaded Con A-liposomes were prepared by incubation of DOX-loaded liposomes with a Con A-SATA derivative. Lectin biological activity was monitored before and after conjugation by a hemagglutinating assay. The cytotoxicity of DOX-loaded Con A-liposomes was evaluated in terms of the inhibition of NCI-H299 and HEp-2 cell proliferation using the MTT method. The affinity of lectinized liposomes with these cells was thus assessed by evaluating the cytotoxic effect of the DOX released into cells. Stable DOX-loaded Con A-liposomes were obtained and their high affinity for cells was corroborated. The encapsulation of DOX into Con A-liposomes produced an inhibition of roughly 70% of Hep-2 cell proliferation and 50% of cell inhibition was verified on HCI-H292. DOX in solution was able to inhibit only 20% of cell proliferation for both cell lines. Unloaded Con A-liposomes were not cytotoxic. The encapsulation of DOX into Con A-liposomes improves drug penetration into cells, thereby enhancing its cytotoxicity, especially in Hep-2 cells. Drug Dev. Res. 67:430,437, 2006. © 2006 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]

In vivo exposure to microcystins induces DNA damage in the haemocytes of the zebra mussel, Dreissena polymorpha, as measured with the comet assay

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2007
Guillaume Juhel
Abstract The Comet assay was used to investigate the potential of the biotoxin microcystin (MC) to induce DNA damage in the freshwater zebra mussel, Dreissena polymorpha. Mussels maintained in the laboratory were fed daily, over a 21-day period, with one of four strains of the cyanobacterium, Microcystis aeruginosa. Three of the strains produced different profiles of MC toxin, while the fourth strain did not produce MCs. The mussels were sampled at 0, 7, 14, and 21 days by withdrawing haemocytes from their adductor muscle. In addition, a positive control was performed by exposing a subsample of the mussels to water containing cadmium chloride (CdCl2). Cell viability, measured with the Fluorescein Diacetate/Ethidium Bromide test, indicated that the MC concentrations, to which the mussels were exposed, were not cytotoxic to the haemocytes. The Comet assay performed on the haemocytes indicated that exposure to CdCl2 produced a dose-responsive increase in DNA damage, demonstrating that mussel haemocytes were sensitive to DNA-damaging agents. DNA damage, measured as percentage tail DNA (%tDNA), was observed in mussels exposed to the three toxic Microcystis strains, but not in mussels exposed to the nontoxic strain. Toxin analysis of the cyanobacterial cultures confirmed that the three MC-producing strains exhibit different toxin profiles, with the two MC variants detected being MC-LF and MC-LR. Furthermore, the DNA damage that was observed appeared to be strain-specific, with high doses of MC-LF being associated with a higher level of genotoxicity than low concentrations of MC-LR. High levels of MC-LF also seemed to induce relatively more persistent DNA damage than small quantities of MC-LR. This study is the first to demonstrate that in vivo exposure to MC-producing strains of cyanobacteria induces DNA damage in the haemocytes of zebra mussels and confirms the sublethal toxicity of these toxins. Environ. Mol. Mutagen., 2007. © 2006 Wiley-Liss, Inc. [source]

Genotoxicity of naturally occurring indole compounds: correlation between covalent DNA binding and other genotoxicity tests

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2002
M. Vijayaraj Reddy
Abstract 3-Methylindole (3MI), melatonin (Mel), serotonin (Ser), and tryptamine (Tryp) were evaluated in vitro for their potential to induce DNA adducts, DNA strand breaks, chromosomal aberrations (Abs), inhibition of DNA synthesis, and mutations. All compounds produced DNA adducts in calf thymus DNA in the presence of rat liver S9. In cultured rat hepatocytes, all produced DNA adducts but none induced DNA strand breaks. In Chinese hamster ovary cells, 3MI and Mel produced DNA adducts, Abs, and inhibition of DNA synthesis with and without S9, except that Mel without S9 did not form adducts. Ser formed DNA adducts, was an equivocal Abs inducer, and suppressed DNA synthesis. Tryp induced neither adducts nor Abs, but did suppress DNA synthesis with S9. Ser and Tryp were less cytotoxic than 3MI and Mel. Mel, Ser, and Tryp failed to induce mutations in Salmonella and E. coli strains with or without S9. 3MI and Mel produced DNA adducts but not mutations in Salmonella TA100 with S9. 3MI and its metabolite indole 3-carbinol also did not induce mutations in a shuttle vector system in human cells. The lack of correlation between DNA adducts and other genotoxicity endpoints for these indole compounds may be due to the higher sensitivity of the 32P-postlabeling adduct assay or it may indicate that the indole-DNA adducts per se are not mutagenic and are not able to induce strand breaks or alkali-labile lesions. The indole-induced Abs may result from cytotoxicity and suppression of DNA synthesis with minimal if any contribution from DNA adducts. Environ. Mol. Mutagen. 40:1,17, 2002. © 2002 Wiley-Liss, Inc. [source]

Dermal benzene and trichloroethylene induce aneuploidy in immature hematopoietic subpopulations in vivo

ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 3 2001
Cynthia R. Giver
Abstract Accumulation of genetic damage in long-lived cell populations with proliferative capacity is implicated in tumorigenesis. Hematopoietic stem cells (hsc) maintain lifetime hematopoiesis, and recent studies demonstrate that hsc in leukemic patients are cytogenetically aberrant. We postulated that exposure to agents associated with increased leukemia risk would induce genomic changes in cells in the hsc compartment. Aneusomy involving chromosomes 2 and 11 in sorted hsc (Lin,c-kit+Sca-1+) and maturing lymphoid and myeloid cells from mice that received topical doses of benzene (bz) or trichloroethylene (TCE) was quantified using fluorescence in situ hybridization. Six days after bz or TCE exposure, aneuploid cells in the hsc compartment increase four- to eightfold in a dose- and schedule-independent manner. Aneuploid lymphoid and myeloid cells from bz- and TCE-treated mice approximate controls, except after repeated benzene exposures. Aneuploid cells are more frequent in the hsc compartment than in mature hematopoietic subpopulations. Hematotoxicity was also quantified in bz- and TCE-exposed hematopoietic subpopulations using two colony-forming assays: CFU-GM (colony-forming units/granulocyte-macrophage progenitors) and CAFC (cobblestone area,forming cells). Data indicate that bz is transiently cytotoxic (,1 week) to hsc subpopulations, and induces more persistent toxicity (>2 weeks) in maturing, committed progenitor subpopulations. TCE is not hematotoxic at the doses applied. In conclusion, we provide direct evidence for induction of aneuploidy in cells in the hsc compartment by topical exposure to bz and TCE. Disruption of genomic integrity and/or toxicity in hsc subpopulations may be one step in leukemic progression. Environ. Mol. Mutagen. 37:185,194, 2001. © 2001 Wiley-Liss, Inc. [source]

Activation of JNK and PAK2 is essential for citrinin-induced apoptosis in a human osteoblast cell line

ENVIRONMENTAL TOXICOLOGY, Issue 4 2009
Yu-Ting Huang
Abstract The mycotoxin citrinin (CTN), a natural contaminant in foodstuffs and animal feeds, exerts cytotoxic and genotoxic effects on various mammalian cells. CTN causes cell injury, including apoptosis. Previous studies by our group showed that CTN triggers apoptosis in mouse embryonic stem cells, as well as embryonic developmental injury. Here, we investigated the precise mechanisms governing this apoptotic effect in osteoblasts. CTN induced apoptotic biochemical changes in a human osteoblast cell line, including activation of c-Jun N-terminal kinase (JNK), loss of mitochondrial membrane potential, and caspase-3 and p21-activated protein kinase 2 (PAK2) activation. Experiments using a JNK-specific inhibitor, SP600125, and antisense oligonucleotides against JNK reduced CTN-induced activation of both JNK and caspase-3 in osteoblasts, indicating that JNK is required for caspase activation in this apoptotic pathway. Experiments using caspase-3 inhibitors and antisense oligonucleotides against PAK2 revealed that active caspase-3 is essential for PAK2 activation. Moreover, both caspase-3 and PAK2 require activation for CTN-induced apoptosis of osteoblasts. Interestingly, CTN stimulates two-stage activation of JNK in human osteoblasts. Early-stage JNK activation is solely ROS-dependent, whereas late-stage activation is dependent on ROS-mediated caspase activity, and regulated by caspase-induced activation of PAK2. On the basis of these results, we propose a signaling cascade model for CTN-induced apoptosis in human osteoblasts involving ROS, JNK, caspases, and PAK2. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009. [source]

Effects of co-culture of amoebae with indoor microbes on their cytotoxic and proinflammatory potential

ENVIRONMENTAL TOXICOLOGY, Issue 4 2007
Terhi Yli-Pirilä
Abstract Free-living amoebae are ubiquitous environmental protozoa found in both natural and man-made environments, including moisture-damaged buildings. Furthermore, the interaction between amoebae and bacteria has been shown to enhance the virulence and pathogenicity of some bacteria. While the inhabitants of moisture damaged buildings are known to be at risk of suffering adverse health effects, the exact causative agents and mechanisms are still obscure. To examine the possible role of amoebae in the health effects associated with moisture damages, the effects of amoebae on the cytotoxicity and proinflammatory potential of nonpathogenic microbes common in moisture-damaged buildings were investigated. First, two bacterial and three fungal strains were cultured both individually and in coculture with Acanthamoeba polyphaga. Then, mouse RAW264.7 macrophages were exposed to the cocultures as well as the individually grown bacteria, fungi, and amoebae. Finally, cell viability and production of proinflammatory mediators, i.e., nitric oxide (NO), tumor necrosis factor , (TNF-,), and interleukin 6 (IL-6), were measured in macrophages after the exposure. The results revealed that cocultivation with amoebae increased the cytotoxicity of the bacterium Streptomyces californicus and the fungus Penicillium spinulosum. Moreover, the macrophages produced up to 10 times higher concentrations of NO after the exposure to these cocultures than after the exposure to individually grown microbes. Finally, the production of the cytokines was up to two orders of magnitude higher (IL-6) and up to four times higher (TNF-,) after exposure to the cocultures when compared to individually grown microbes. We conclude that amoebae are able to potentiate the cytotoxicity and proinflammatory properties of certain microbes associated with moisture damages. © 2007 Wiley Periodicals, Inc. Environ Toxicol 22: 357,367, 2007. [source]

Effect of byproducts from the ozonation of pyrene: Biphenyl-2,2,,6,6,-tetracarbaldehyde and biphenyl-2,2,,6,6,-tetracarboxylic acid on gap junction intercellular communication and neutrophil function

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2005
Stephanie L. Luster-Teasley
Abstract In this study, biphenyl-2,2,,6,6,-tetracarbaldehyde, an initial by product formed from the ozonation of pyrene, and biphenyl-2,2,,6,6,-tetracarboxylic acid, a subsequent pyrene ozonation byproduct, were evaluated using two toxicology assays to compare the toxicity of ozonation byproducts with that of the parent compound. The first assay measured the potential for the compounds to block gap junctional intercellular communication (GJIC) using the scrape loading/dye transfer technique in normal WB-344 rat liver epithelial cells. The second assay evaluated the ability of the compounds to affect neutrophil function by measuring the production of superoxide in a human cell line (HL-60). Pyrene significantly blocked intercellular communication (f= 0.2,0.5) at 40 ,M and complete inhibition of communication (f < 0.2) occurred at 50 ,M. Gap junctional intercellular communication in cells exposed to biphenyl-2,2,,6,6,-tetracarbaldehyde reached f < 0.5 at a concentration of 15 ,M. At concentrations greater than 20 ,M, biphenyl-2,2,,6,6,-tetracarbaldehyde was cytotoxic and the inhibition of GJIC was caused by cell death. Biphenyl-2,2,,6,6,-tetracarboxylic acid was neither cytotoxic nor inhibitory to GJIC at the concentrations tested (10,500 ,M). Exposure to biphenyl-2,2,,6,6,-tetracarbaldehyde resulted in a concentration-dependent decrease in phorbol 12-myristate 13-acetate,stimulated O12 production. Neither exposure to pyrene nor biphenyl-2,2,,6,6,-tetracarboxylic acid caused a significant toxic effect on neutrophil function. [source]

Cytotoxicity of settling particulate matter and sediments of the Neckar River (Germany) during a winter flood

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2000
Henner Hollert
Abstract To investigate the cytotoxic and genotoxic potentials of settling particulate matter (SPM) carried by the Neckar River, a well-studied model for a lock-regulated river in central Europe, during a flood, acute cytotoxicity was investigated using the fibroblast-like fish cell line RTG-2 with the neutral red retention, the succinic acid dehydrogenase (MTT), and the lactatedehydro-genase (LDH) release assays as well as microscopic inspection as endpoints. Genotoxicity of water, pore water, sediments, and SPM were assessed using the Ames test. Different extraction methods (Soxhlet extraction with solvents of variable polarity as well as a fluid/fluid extraction according to pH) in addition to a supplementation of biotests with S9 fractions from the liver of ,-naphthoflavone/phenobarbital-induced rats allowed a further characterization of the biological damage. Both sediments and SPM extracts caused cytotoxic effects in RTG-2 cells. Cytotoxicity was found to increase significantly with polarity of extracting solvents (NR50 = effective concentration for 50% cell death in the neutral red test: 80 [65], 100 [70], 180 [220], and 225 [270] mg/ml for ethanol, acetone, dichloromethane, and n -hexane extracts, respectively, if measured with [without] S9 supplementation). Following extraction according to pH, cytotoxicity could be attributed mainly to neutral substances (NR50: 80 and 218 mg dry SPM/ml test medium for the neutral and the acid fractions, respectively), whereas the slightly acid and basic fractions already showed little or no cytotoxicity. Samples taken during the period of flood rise showed the highest cytotoxic activities. Cytotoxicity was significantly enhanced by the addition of S9 preparations. In contrast, no genotoxic activity was found in native surface waters, pore waters, and SPM. [source]

Parabolic flight primes cytotoxic capabilities of polymorphonuclear leucocytes in humans

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2009
I. Kaufmann
Abstract Background, Previously performed in vitro studies suggested that gravitational stress may alter functions of immune cells. This study investigated the in vivo effects of parabolic flight manoeuvres as a short-term model of micro- and hypergravity on the cytotoxic and microbicidal polymorphonuclear leucocyte (PMN) functions as the key element of innate immunity. Material and methods, Twenty-one healthy male volunteers underwent 30 subsequent parabolic flight manoeuvres. Each manoeuvre produced 22-s periods of nearly weightlessness close to «0g», with each parabola starting with a pull-up and ending with a pull-out (hypergravity) at 1·8 g for about 20 s each. Blood samples were drawn 24 h prior to take off (T0), after 25,30 parabolas (T1), and 24 h (T2) and 48 h (T3) after flight for determination of (i) leucocyte number and subpopulations, (ii) PMNs' capabilities to produce hydrogen peroxide (H2O2) and to adhere and phagocytose particles and (iii) plasma cytokines known to prime PMN functions [interleukin-8 (IL-8), tumour necrosis factor-, (TNF-,), granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF)]. Results, Parabolic flight induced an increase in leucocyte number with a significant elevation of the PMN fraction. The spontaneous H2O2 production by PMNs did not change; however, the capability of PMNs to produce H2O2 in response to soluble stimuli [N -formyl-methionyl-leucyl-phenylalanine (fMLP), fMLP and TNF-,, calcium ionophore (A23187), phorbol myristate acetate (PMA)] was increased. Adhesive and phagocytic properties of PMNs were not altered. Regarding priming cytokines, IL-8 and G-CSF were significantly elevated. Conclusions, Our data indicate that parabolic flight induces priming of the cytotoxic capabilities of PMNs without affecting microbicidal functions. [source]

B-cell co-receptor CD72 is expressed on NK cells and inhibits IFN-, production but not cytotoxicity

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2009
Valeria L. Alcón
Abstract NK cells have two main functions, namely cell-mediated cytotoxicity and production of cytokines. Multiple inhibitory receptors that regulate NK-cell cytotoxicity have been characterized whereas little is known about receptors regulating cytokine production. Here we report that CD72, which is considered to be an important co-receptor regulating B-cell activation, is also expressed on mouse NK cells. NK cells expressing high levels of CD72, upon stimulation with IL-12 and IL-18 or target cells, produce significantly less IFN-, than those expressing low levels of CD72, whereas both subsets are equally cytotoxic. Ectopic expression of CD72 in the murine NK-cell line KY2 inhibits cytokine-induced IFN-, production, and the inhibitory effect is diminished by mutations in the inhibitory motifs in the intracellular domain or replacement of the extracellular domain of CD72. Thus, CD72 is an inhibitory receptor on NK cells regulating cytokine production. [source]

Proliferation and interleukin,5 production by CD8hiCD57+ T cells

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2008

Abstract CD8hiCD57+ T cells have previously been described as effector memory T cells with minimal expansion capacity and high susceptibility to activation-induced cell death. In contrast, we demonstrate here that CD8hiCD57+ T cells are capable of rapid expansion using multiple techniques including [3H]thymidine uptake, flow cytometric bead-based enumeration and standard haemocytometer counting. Previous reports can be explained by marked inhibition of activation-induced expansion and increased 7-amino-actinomycin,D uptake by CD8hiCD57+ T cells following treatment with CFSE, a dye previously used to measure their proliferation, combined with specific media requirements for the growth of this cell subset. The ability of CD8hiCD57+ T cells to further differentiate is highlighted by a distinct cytokine profile late after activation that includes the unexpected release of high levels of interleukin,5. These data indicate that CD8hiCD57+ T cells should not be considered as "end-stage" effector T cells incapable of proliferation, but represent a highly differentiated subset capable of rapid division and exhibiting novel functions separate from their previously described cytotoxic and IFN-, responses. [source]

Reconstitution of anti-HIV effector functions of primary human CD8 T,lymphocytes by transfer of HIV-specific ,,,TCR genes

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2004
Takamasa Ueno
Abstract We redirected the antigen specificity of primary human CD8 T,cells by retrovirus-mediated transduction of genes encoding ,,,TCR specific to HIV-1 Pol protein. A large polyclonal population of TCR-transduced CD8 T,cells showed substantial cytotoxic and cytokine production activities toward target cells either pulsed with the peptide or infected with HIV-1, and their functional activities were comparable to those of the parental CTL clone. Peptide fine-specificity and promiscuous recognition of HLA class,I supertypes of the parental CTL clone were also preserved in the TCR-transduced cells. There were no signs of allogeneic responses in these cells, although hybrid TCR dimers consisting of transduced TCR and endogenous TCR were suspected to have been formed in these cells, as the effect of transgene expression on the surface expression of the desired TCR was limited. Moreover, the TCR-transduced cells showed potent inhibitory activity against HIV-1 replication in vitro, although the differential surface expression of the desired TCR resulted in differential functional avidity of individual TCR-transduced cells toward the peptide-pulsed target cells. These data suggest that the reconstitution of HIV-specific immunoreactive T,cells engineered by genetic transfer of HIV-specific TCR is a potential alternative to immunotherapeutic applications against HIV infections. [source]

Influence of the Diketonato Ligand on the Cytotoxicities of [Ru(,6 - p -cymene)(R2acac)(PTA)]+ Complexes (PTA = 1,3,5-triaza-7-phosphaadamantane)

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2008
Carsten A. Vock
Abstract A series of compounds of general formula [Ru(,6 - p -cymene)(R2acac)(PTA)][X] (R2acac = Me2acac, tBu2acac, Ph2acac, Me2acac-Cl; PTA = 1,3,5-triaza-7-phosphaadamantane; X = BPh4, BF4), and the precursor to the Me2acac-Cl derivative [Ru(,6 - p -cymene)(Me2acac-Cl)Cl], have been prepared and characterised spectroscopically. Five of the compounds have also been characterised in the solid state by X-ray crystallography. The tetrafluoroborate salts are water-soluble, quite resistant to hydrolysis, and have been evaluated for cytotoxicity against A549 lung carcinoma and A2780 human ovarian cancer cells. The compounds are cytotoxic towards the latter cell line, and relative activities are discussed in terms of hydrolysis (less important) and lipophilicity, which appears to exert the dominating influence. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

The ubiquitin-proteasome system and its role in ethanol-induced disorders

ADDICTION BIOLOGY, Issue 1 2002
Terrence M. Donohue Jr
The levels of these proteins are controlled by their rates of degradation. Similarly, protein catabolism plays a crucial role in prolonging cellular life by destroying damaged proteins that are potentially cytotoxic. A major player in these catabolic reactions is the ubiquitin-proteasome system, a novel proteolytic system that has become the primary proteolytic pathway in eukaryotic cells. Ubiquitin-mediated proteolysis is now regarded as the major pathway by which most intracellular proteins are destroyed. Equally important, from a toxicological standpoint, is that the ubiquitin-proteasome system is also widely considered to be a cellular defense mechanism, since it is involved in the removal of damaged proteins generated by adduct formation and oxidative stress. This review describes the history and the components of the ubiquitin-proteasome system, its regulation and its role in pathological states, with the major emphasis on ethanol-induced organ injury. The available literature cited here deals mainly with the effects of ethanol consumption on the ubiquitin-proteasome pathway in the liver. However, since this proteolytic system is an essential pathway in all cells it is an attractive experimental model and therapeutic target in extrahepatic organs such as the brain and heart that are also affected by excessive alcohol consumption. [source]