Search results for "TOXICITY"
showing 10 items of 2261 documents
Phenoloxidase-dependent cytotoxic mechanism in ascidian (Styela plicata) hemocytes active against erythrocytes and K562 tumor cells.
1997
The cytotoxic activity against rabbit erythrocytes (RE) and human K562 tumor cells by Styela plicata hemocytes was significantly related to the phenoloxidase (PO) which converts phenols to quinone and initiates the melanogenic pathway. The effector hemocyte population, separated in a Percoll density gradient band, enriched in a granulocyte type named "morula cells", was examined with RE in a hemocyte cytotoxic assay and plaque forming cell assay. Inhibition experiments with the copper chelating agents 1-phenyl-2-thiourea and tropolone, the substrate analogue sodium benzoate and sodium ascorbate support the notion that hemocyte cytotoxic activity is a PO-dependent mechanism. Treatments of he…
Sugammadex, a Neuromuscular Blockade Reversal Agent, Causes Neuronal Apoptosis in Primary Cultures
2013
Sugammadex, a γ-cyclodextrin that encapsulates selectively steroidal neuromuscular blocking agents, such as rocuronium or vecuronium, has changed the face of clinical neuromuscular pharmacology. Sugammadex allows a rapid reversal of muscle paralysis. Sugammadex appears to be safe and well tolerated. Its blood-brain barrier penetration is poor (< 3% in rats), and thus no relevant central nervous toxicity is expected. However the blood brain barrier permeability can be altered under different conditions (i.e. neurodegenerative diseases, trauma, ischemia, infections, or immature nervous system). Using MTT, confocal microscopy, caspase-3 activity, cholesterol quantification and Western-blot we …
Analysis of DNA single-strand breaks in human venous blood: a technique which does not require isolation of white blood cells.
1997
For DNA strand break analysis in human white blood cells, usually metrizoate-Ficoll centrifugation is used to isolate mononuclear cells. This procedure is time-consuming and requires at least 20 ml of blood per sample. Therefore, we developed a technique which does not require isolation of white blood cells prior to DNA strand break analysis by alkaline elution (direct method). The sensitivity of this new technique was compared to that of the standard method, which includes isolation of mononuclear blood cells. A statistically significant increase in sensitivity was observed using the direct method. After in vitro gamma-irradiation of venous blood, an increase in the elusion rate of 7.7 × 1…
Recombinant expression of human microsomal epoxide hydrolase protects V79 Chinese hamster cells from styrene oxide- but not from ethylene oxide-induc…
1997
Styrene 7,8-oxide and ethylene oxide are widely used genotoxic bulk chemicals, which have been associated with potential carcinogenic hazard for occupationally exposed workers. Both epoxides alkylate DNA preferentially at the N-7 position of guanine and consequently produce single-strand breaks and alkali labile sites in the DNA of exposed cells. In order to study the role of human microsomal epoxide hydrolase (hmEH) in protecting cells against genotoxicity of styrene 7,8-oxide and ethylene oxide, we expressed the cDNA of hmEH in V79 Chinese hamster cells. We obtained a number of cell clones that expressed functionally active epoxide hydrolase. Among these, the clone 92hmEH-V79 revealed an …
Enhancement of the Mutagenicity of Ethylene Oxide and Several Directly Acting Mutagens by Human Erythrocytes and its Reduction by Xenobiotic Interact…
1999
According to the present state of knowledge mutagenicity or genotoxicity of the ulti mate genotoxic agents ethylene oxide or styrene oxide cannot be increased by further me tabolism. However, in the present study we demonstrate that mutagenicity of several ultimate genotoxic substances is increased by human erythrocytes. For instance mu tagenicity of mafosfamide, N-nitroso-N-methylurea, ethylene oxide, and styrene oxide to Salmonella typhimurium TA 1535 was increased 5.5-, 5.1-, 2.7-, and 2.3-fold, respectively, by addition of human erythrocyte homogenate to the preincubation mixture in the Ames test. On the other hand, the mutagenicity of cumene hydroperoxide, benzo[a]pyrene-4,5-oxide, and…
Quantitative genetic analysis of Cry1Ab tolerance in Ostrinia nubilalis Spanish populations
2013
30 p.-2 fig.-3 tab.
Synthesis and antibacterial activities of cadiolides A, B and C and analogues
2015
International audience; The one-pot multicomponent synthesis of natural butenolides named cadiolides A, B, C and analogues has been realized. The antibacterial structure activity relationship shows that the presence of phenolic hydroxyl groups and the number and position of bromine atoms on the different aromatic rings are important features for antibacterial activity, besides it was demonstrated the tolerance of both benzene and furan ring at position 3 of the butenolide nucleus. Furthermore, none of the most relevant antibacterial compounds showed any cytotoxicity in freshly isolated human neutrophils.
The CD95/CD95 ligand system is not the major effector in anticancer drug-mediated apoptosis.
1998
Many anticancer drugs are able to induce apoptosis in tumor cells but the mechanisms underlying this phenomenon are poorly understood. Some authors reported that the p53 tumor suppressor gene may be responsible for drug-induced apoptosis; however, chemotherapy-induced apoptosis can also be observed in p53 negative cells. Recently, doxorubicin (DXR) was reported to induce CD95L expression to mediate apoptosis through the CD95/CD95L system. Thus, an impairment of such a system may be involved in drug resistance. We evaluated the in vitro antitumor activity of several cytotoxic drugs on two human p53-negative T-cell lymphoma cell lines, the HUT78-B1 CD95L-resistant cell line and the HUT78 pare…
FIBRONECTIN (FN) AND UROTHELIAL DAMAGE SECONDARY TO ADJUVANT INTRAVESICAL THERAPY
2014
Introduction and Objectives: Intravesical chemotherapy has been proven effective in preventing recurrence of low-risk non-muscle invasive bladder cancer (NMIBC). BCG is recognised as the best conservative treatment for intermediate and high risk NMIBC. Maintenance for at least one year is required to ameliorate the efficacy of adjuvant therapy. Discomfort and toxicity often cause interruption of adjuvant therapy, BCG particularly. Almost 50% of the patients undergoing BCG does not complete one year. A biomarker of urothelium damage would be helpful for timely detection of toxicity in order to ameliorate patient’s tolerance and compliance. The aim of the present study was to evaluate the gen…
Do laboratory exposures represent field exposures? Effects of sediments contaminated by wood industry on yolk-sac fry of rainbow trout (Oncorhynchus …
2015
Purpose. Risk assessment of contaminated sediments is routinely based on laboratory exposures. The purpose of this work was to study if sediments contaminated by the chemical wood industry cause developmental defects in fish fry and how well a laboratory exposure correlates with a field exposure. Materials and methods. Newly hatched yolk-sac fry of rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory and in situ. In the laboratory, the fish were placed in contact with either clean or contaminated sediment in aquaria. In the field, half of the fish were placed in contact with the lake sediment and the other half were similarly caged 2 m above it, to discern the effects of the s…