Search results for "TOXICITY"

Isolation and cytotoxic activity of neurotoxin from the mucus of Actinia equina (Anthozoa, Cnidaria).

2011

Protection of Flupirtine on β-Amyloid-Induced Apoptosis in Neuronal Cells In Vitro: Prevention of Amyloid-Induced Glutathione Depletion

2002

Effective drugs are not available to protect against beta-amyloid peptide (A beta)-induced neurotoxicity. Cortical neurons from rat embryos were treated with the toxic fragment A beta25-35 at 1 microM in the presence or absence of flupirtine, a triaminopyridine, successfully applied clinically as a nonopiate analgesic drug. Five days later 1 microM A beta25-35 caused reduction of cell viability to 31.1%. Preincubation of cells with flupirtine (1 or 5 microg/ml) resulted in a significant increase of the percentage of viable cells (74.6 and 65.4%, respectively). During incubation with A beta25-35 the neurons undergo apoptosis as determined by appearance of the characteristic stepladder-like D…

An in vitro model to study cellular photosensitizer uptake and photodynamic dose-response relationships of tumor cells

1993

Cellular fluorescence intensity (CFI) after incubation with varying concentrations of the photosensitizer Photofrin and the photodynamically induced dose-response relationships of hamster melanoma cells (A-MEL-3) were studied in a recently developed in vitro model. After administration of Photofrin to the extracellular serum-free medium, CFI was evaluated by flow cytometry together with constantly fluorescing latex particles used as a reference. After 5 min, 50% of maximal CFI was found, and after 60 min CFI was maximal. No further increase was obtained during the exposure to Photofrin over the incubation period of 4 h. During this plateau phase, CFI was significantly related to the concent…

Exploratory study on the effects of biodegradable nanoparticles with drugs on malignant B cells and on a human/mouse model of Burkitt lymphoma.

2010

The aim of this study was to determine if Rituximab coated Biodegradable Nanoparticles (BNPs) loaded with Chlorambucil and Hydroxychloroquine could induce apoptosis of B-Chronic Lymphocytic Leukemia (B-CLL), MEC-1 and BJAB cells in vitro and evaluate their toxic and therapeutic effects on a Human/Mouse Model of Burkitt Lymphoma at an exploratory, proof of concept scale. We found that Rituximab-Chlorambucil-Hydroxychloroquine BNPs induce a decrease in cell viability of malignant B cells in a dose-dependent manner. The mediated cytotoxicity resulted from apoptosis, and was confirmed by monitoring the B-CLL cells after Annexin V/propidium iodide staining. Additional data revealed that these BN…

Clinical concentrations of efavirenz (EFV) reduce cellular proliferation and viability in several human cell lines

2008

Results MTT assays upon 24 h of culture in the presence of the drug revealed reduced viability in the human hepatoma cell line Hep3B (significant for all three concentrations and calculated as 84.59 ± 8.82% decrease for 50 μM EFV), human cervix carcinoma cell line HeLa (71.92 ± 5.49% reduction for 50 μM EFV) and primary Human Umbilical Vein Endothelial cells (HUVEC), (96.76 ± 0.27% reduction for 50 μM EFV). This result was corroborated with 3day-proliferation experiments in which Hep3B were exposed to different concentrations of EFV; a significant reduction (60.1 ± 6.54% after 3 days) was detected with 25 μM EFV whereas cytotoxicity (97.01 ± 1.13% reduction) was observed with 50 μM, however…

Toxicity test of a dental commercial composite in rats.

2011

Objective: The aim of this study was to determine the 90-day subchronic toxicity of one triethylene glycol dimethacrylate containing composite (MEDENTAL Light-Cure Composite™) orally administered to rats according to OECD no. 48 guidelines and the requirements specified in the International Organization for Standardization 10993-11. Study design: The composite was administered orally to Wistar rats during 90 days and they were observed to determine changes in their behavior, eye and skin signs and other attitudes such as aggressiveness, posture, walking and response to handling. After 90 days they were sacrificed to determine blood alterations, special hematological tests were done and hist…

Refining in vitro neurotoxicity testing--the development of blood-brain barrier models.

2003

The purpose of this paper is to review the current state of development of advanced in vitro blood–brain barrier (BBB) models. The BBB is a special capillary bed that separates the blood from the central nervous system (CNS) parenchyma. Astrocytes maintain the integrity of the BBB, and, without astrocytic contacts, isolated brain capillary endothelial cells in culture lose their barrier characteristics. Therefore, when developing in vitro BBB models, it is important to add astrocytic factors into the culture system. Recently, novel filter techniques and co-culture methods have made it possible to develop models which resemble the in vivo functions of the BBB in an effective way. With a BBB…

Contact hypersensitivity to disodium hexachloroplatinate in mice.

1998

Complex platinum (Pt) compounds are known as occupational respiratory sensitizers whereas their role in skin exposure is unclear. In this study, both skin irritation and induction of contact hypersensitivity by halide Pt salts were characterized in mice. Repeated application of Na2[PtCl6] (5% in acetone) to both ears of naive BALB/c mice induced activation of the draining auricular lymph nodes. Flow cytometric analysis revealed a striking increase in the number of lymph node cells expressing proliferating cell nuclear antigen. In separate experiments, Na2[PtCl6] or acetone were applied only to the right ear of mice on 4-8 consecutive days and the animals were challenged on the left ear 6 da…

Adhesion prophylaxis using a copolymer with rationally designed material properties.

2008

Physical barriers are the only licensed adjuncts for adhesion prophylaxis in the United States and Europe. Here, we investigate D,L-polylactide-epsilon-caprolactonetrimethylenecarbonate (PCT copolymer), which is a rationally designed biomaterial, as an adhesion barrier.PCT copolymer membranes were produced by polymerization of the monomers, dissolution in organic solvents, and subsequently processing them by means of modified phase inversion and freeze drying. In vitro cytotoxicity was assayed by fibroblast culture. In vivo adhesion prophylaxis was studied in a rat model that involved standardized traumatization by electrocautery and suturing. The quantity and quality of the resulting adhes…

Use of flow cytometry and confocal microscopy techniques to investigate early CdCl(2)-induced nephrotoxicity in vitro.

2001

CdCl(2) is a well-known toxic compound for the kidney in vivo and in vitro. We report here part of the results of an ECVAM (European Centre for the Validation of Alternative Methods) contract study, aimed at establishing and assessing several flow cytometric and confocal microscopic endpoints for use in an in vitro nephrotoxicity model. Three renal tubule cell lines, OK (opossum, proximal tubule origin), LLC-PK1 (pig, proximal tubule origin) and MDCK (dog, distal tubule origin) were exposed for 1, 5 and 24 h to 25 microM and 100 microM CdCl(2). The results obtained for mitochondrial membrane potential showed a decrease in all the cell lines after 5 h of treatment with both CdCl(2) concentra…