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1.
Regul Toxicol Pharmacol ; 118: 104787, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33011233

RESUMO

Bisphenol A (BPA) belongs to a group of chemicals used in the production of polycarbonate, polysulfone, and polyethersulfone which are used, among other applications, in the manufacture of dialyzers. While exposure to BPA is widespread in the general population, dialysis patients represent a population with potentially chronic parenteral BPA exposures. To assess the potential risk of BPA exposure to dialysis patients through dialyzer use, exposure estimates were calculated based on BPA levels measured by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry following extractions from dialyzers manufactured by Fresenius Medical Care. Extraction conditions included both simulated-use leaching and exaggerated extractions to evaluate possible leachable and extractable BPA, respectively, from the devices. The mean BPA concentrations were 3.6 and 108.9 ppb from simulated-use and exaggerated extractions, respectively, from polycarbonate-containing dialyzers. No BPA was detected from polypropylene-containing dialyzers. Margins of Safety (MOS) were calculated to evaluate the level of risk to patients from estimated BPA exposure from the dialyzers, and the resulting MOS were 229 and 45 for simulated-use and exaggerated extractions, respectively. The findings suggest that there is an acceptable level of toxicological risk to dialysis patients exposed to BPA from use of the dialyzers tested in the current study.


Assuntos
Compostos Benzidrílicos/análise , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Membranas Artificiais , Fenóis/análise , Cimento de Policarboxilato/análise , Polipropilenos/análise , Diálise Renal/instrumentação , Testes de Toxicidade , Compostos Benzidrílicos/toxicidade , Humanos , Fenóis/toxicidade , Cimento de Policarboxilato/toxicidade , Polipropilenos/toxicidade , Medição de Risco
2.
Toxicol Lett ; 317: 1-12, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31562913

RESUMO

During extrusion of some polymers, fused filament fabrication (FFF) 3-D printers emit billions of particles per minute and numerous organic compounds. The scope of this study was to evaluate FFF 3-D printer emission-induced toxicity in human small airway epithelial cells (SAEC). Emissions were generated from a commercially available 3-D printer inside a chamber, while operating for 1.5 h with acrylonitrile butadiene styrene (ABS) or polycarbonate (PC) filaments, and collected in cell culture medium. Characterization of the culture medium revealed that repeat print runs with an identical filament yield various amounts of particles and organic compounds. Mean particle sizes in cell culture medium were 201 ±â€¯18 nm and 202 ±â€¯8 nm for PC and ABS, respectively. At 24 h post-exposure, both PC and ABS emissions induced a dose dependent significant cytotoxicity, oxidative stress, apoptosis, necrosis, and production of pro-inflammatory cytokines and chemokines in SAEC. Though the emissions may not completely represent all possible exposure scenarios, this study indicate that the FFF could induce toxicological effects. Further studies are needed to quantify the detected chemicals in the emissions and their corresponding toxicological effects.


Assuntos
Resinas Acrílicas/toxicidade , Butadienos/toxicidade , Células Epiteliais/efeitos dos fármacos , Nanopartículas/toxicidade , Cimento de Policarboxilato/toxicidade , Poliestirenos/toxicidade , Impressão Tridimensional , Mucosa Respiratória/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Células Epiteliais/ultraestrutura , Humanos , Mediadores da Inflamação/metabolismo , Necrose , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Mucosa Respiratória/metabolismo , Mucosa Respiratória/ultraestrutura , Medição de Risco , Fatores de Tempo
3.
Eur J Pharm Biopharm ; 88(3): 962-72, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25127989

RESUMO

Recently, we reported the synthesis and biocompatibility of alkoxylphenacyl-based polycarbonates (APP); a promising new class of polymers that undergo photo-induced chain scission. In the current study, nanoparticles (NPs) were prepared from the APP polymer (APP-NPs) and loaded with doxorubicin (DOX) (DOX-APP-NPs) in order to identify and evaluate formulation and photoirradiation parameters that influence photoresponsive efficacy. Stable and spherical APP-NPs were prepared with diameters between 70-80nm depending on APP concentration (10-40mg/mL). There was a direct relationship between APP concentration and resultant particle size. Drug release studies indicated that exposure to the photo-trigger was capable of altering the rate and extent of DOX released. Photoresponsive DOX release was markedly influenced by the frequency of photoirradiation while the effect of APP concentration was most likely propagated through NP size. DOX released by photoactivation retained its efficacy as assessed by cytotoxicity studies in human lung adenocarcinoma (A549) cells. Studies in BALB/c mice indicated that DOX-APP-NPs induce less cardiotoxicity than DOX alone and that DOX-APP-NPs are not susceptible to dose dumping after photoirradiation.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Estimulação Luminosa/métodos , Fármacos Fotossensibilizantes/síntese química , Cimento de Policarboxilato/síntese química , Animais , Linhagem Celular Tumoral , Química Farmacêutica , Relação Dose-Resposta a Droga , Coração/efeitos dos fármacos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Fármacos Fotossensibilizantes/efeitos da radiação , Fármacos Fotossensibilizantes/toxicidade , Cimento de Policarboxilato/efeitos da radiação , Cimento de Policarboxilato/toxicidade
4.
J Mater Sci Mater Med ; 25(1): 131-9, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24062230

RESUMO

In this paper, novel biodegradable amphiphilic block-graft copolymers based on methoxy poly(ethylene glycol)-b-(polycarbonates-g-polycarbonates) (mPEG-b-(PATMC-g-PATMC)) were synthesized successfully for controlled release of doxorubicin (DOX). Backbone block copolymer, methoxy poly(ethylene glycol)-b-poly(5-allyloxy-1,3-dioxan-2-one) (mPEG-b-PATMC) was synthesized in bulk catalyzed by immobilized porcine pancreas lipase (IPPL). Then, mPEG-b-PATMC-O, the allyl epoxidation product of mPEG-b-PATMC, was further grafted by PATMC itself also using IPPL as the catalyst. The copolymers were characterized by (1)N HMR and gel permeation chromatography results showed narrow molecular weight distributions. Stable micelle solutions could be prepared by dialysis method, while a monomodal and narrow size distribution could be obtained. Transmission electron microscopy (TEM) observation showed the micelles dispersed in spherical shape with nano-size before and after DOX loading. Compared with the block copolymers, the grafted structure could enhance the interaction of polymer chains with drug molecules and improve the drug-loading capacity and entrapment efficiency. Furthermore, the amphiphilic block-graft copolymers mPEG-b-(PATMC-g-PATMC) had low cytotoxicity and more sustained drug release behavior.


Assuntos
Doxorrubicina/administração & dosagem , Sistemas de Liberação de Medicamentos , Implantes Absorvíveis , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Proliferação de Células/efeitos dos fármacos , Enzimas Imobilizadas , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lipase , Teste de Materiais , Micelas , Estrutura Molecular , Cimento de Policarboxilato/química , Cimento de Policarboxilato/toxicidade , Polietilenoglicóis/química , Polietilenoglicóis/toxicidade , Polímeros/química , Polímeros/toxicidade
5.
J Pharm Sci ; 102(5): 1650-60, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23529816

RESUMO

Potential toxicities of chromophoric or polymeric units of most photoresponsive delivery systems have impacted clinical relevance. Herein, we evaluated the biocompatibility and tolerability of alkoxylphenacyl-based polycarbonates (APPs) as a new class of photoresponsive polymers. The polymers were applied as homopolymer or copolymers of polyethylene glycol (10%, w/w) or polycaprolactone (10%, w/w). APP polymers were comparable to poly(lactic-co-glycolic acid) (PLGA) based on cytotoxicity, macrophage activation, and blood compatibility. Data from biodistribution studies in BALB/c mice showed preferential accumulation in kidney and liver. Meanwhile, potential application of APP polymers as immediate or sustained (implants) drug delivery systems indicated that liver and kidney functions were not distorted. Also, plasma levels of tumor necrosis factor-alpha and interleukin-6 were comparable to PLGA-treated mice (p > 0.05). A histological analysis of liver and kidney sections showed no detectable damage for APP polymers. The overall data strongly supported potential consideration of APP polymers as photoresponsive delivery systems especially as implantable or tissue-mimicking photopatterned biomaterials.


Assuntos
Materiais Biocompatíveis/metabolismo , Materiais Biocompatíveis/toxicidade , Cimento de Policarboxilato/metabolismo , Cimento de Policarboxilato/toxicidade , Alanina Transaminase/sangue , Animais , Materiais Biocompatíveis/química , Linhagem Celular , Creatina/sangue , Citocinas/análise , Eritrócitos/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Rim/efeitos dos fármacos , Rim/patologia , Luz , Fígado/efeitos dos fármacos , Fígado/patologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Cimento de Policarboxilato/química , Ratos , Ratos Sprague-Dawley
6.
Dent Mater ; 29(3): e35-44, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23103048

RESUMO

OBJECTIVES: The aim of the study was to evaluate the biological effects of water eluents from polycarbonate based esthetic orthodontic brackets. METHODS: The composite polycarbonate brackets tested were Silkon Plus (SL, fiber-glass-reinforced), Elan ME (EL, ceramic particle-reinforced) and Elegance (EG, fiber-glass-reinforced). An unfilled polyoxymethylene bracket (Brilliant, BR) was used as control. The brackets' composition was analyzed by ATR-FTIR spectrometry. The cytotoxicity and estrogenicity of the eluents obtained after 3 months storage of the brackets in water (37 °C) were investigated in murine fibroblasts (NIH 3T3), breast (MCF-7) and cervical cancer (CCl-2/Hela) cell lines. RESULTS: SL and EG were based on aromatic-polycarbonate matrix, whereas EL consisted of an aromatic polycarbonate-polyethylene terepthalate copolymer. A significant induction of cell death and a concurrent decrease in cell proliferation was noted in the EG eluent-treated cells. Moreover, EG eluent significantly reduced the levels of the estrogen signaling associated gene pS2, specifically in MCF7 cells, suggesting that cell death induced by this material is associated with downregulation of estrogen signaling pathways. Even though oxidative stress mechanisms were equally activated by all eluents, the EG eluents induced expression of apoptosis inducing factor (AIF) and reduced Bcl-xL protein levels. SIGNIFICANCE: Some polycarbonate-based composite brackets when exposed to water release substances than activate mitochondrial apoptosis.


Assuntos
Apoptose/efeitos dos fármacos , Estrogênios/análise , Mitocôndrias/efeitos dos fármacos , Braquetes Ortodônticos/efeitos adversos , Cimento de Policarboxilato/toxicidade , Análise de Variância , Animais , Fator de Indução de Apoptose/metabolismo , Ensaio de Imunoadsorção Enzimática , Células HeLa , Humanos , Células MCF-7 , Camundongos , Mitocôndrias/metabolismo , Células NIH 3T3 , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Espectroscopia de Infravermelho com Transformada de Fourier
7.
Am J Orthod Dentofacial Orthop ; 142(1): 70-4, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22748992

RESUMO

INTRODUCTION: In this study, we evaluated the cellular viability of various esthetic, metallic, and nickel-free orthodontic brackets. METHODS: The sample was divided into 11 groups (n = 8): cellular control, negative control, positive control, metallic, polycarbonate, 2 types of monocrystalline ceramic, 3 types of nickel free, and polycrystalline ceramic brackets. Cell culture (NIH/3T3-mice fibroblasts) was added to the plates of 96 wells containing the specimens and incubated in 5% carbon dioxide at 37°C for 24 hours. Cytotoxicity was analyzed qualitatively and quantitatively. Cell growth was analyzed with an inverted light microscope, photomicrographs were obtained, and the results were recorded as response rates based on modifications of the parameters of Stanford according to the size of diffusion halo of toxic substances. Cell viability was analyzed (MTT assay); a microplate reader recorded the cell viability through the mitochondrial activity in a length of 570 nm. The values were statistically analyzed. RESULTS: All tested brackets had higher cytotoxicity values than did the negative control (P <0.05), with the exception Rematitan and Equilibrium (both, Dentaurum, Ispringen, Germany) (P >0.05), suggesting low toxicity effects. The values showed that only polycarbonate brackets were similar (P >0.05) to the positive control, suggesting high toxicity. CONCLUSIONS: The brackets demonstrated different ranges of cytotoxicity; nickel-free brackets had better biocompatibility than the others. On the other hand, polycarbonate brackets were made of a highly cytotoxic material for the cells analyzed.


Assuntos
Ligas Dentárias/toxicidade , Materiais Dentários/toxicidade , Braquetes Ortodônticos , Alumínio/toxicidade , Animais , Compostos Benzidrílicos , Materiais Biocompatíveis/toxicidade , Dióxido de Carbono/administração & dosagem , Técnicas de Cultura de Células , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cerâmica/toxicidade , Ligas de Cromo/química , Corantes , Estética Dentária , Fibroblastos/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Níquel/toxicidade , Fenóis/toxicidade , Cimento de Policarboxilato/toxicidade , Temperatura , Sais de Tetrazólio , Tiazóis , Fatores de Tempo , Titânio/toxicidade
8.
Am J Orthod Dentofacial Orthop ; 137(5): 665-70, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20451786

RESUMO

INTRODUCTION: Ceramic brackets are chemically inert in the oral cavity, whereas polycarbonate and polyoxymethylene brackets can degrade and release bisphenol-A and formaldehyde, respectively. More reliable tests are needed to assess the potential toxicity of these materials. In addition to traditional cytotoxicity tests, the study of nitric oxide (NO) cellular production stimulated by a specific material has been shown to be a reliable tool for evaluating cytotoxic potential. The purpose of this study was to assess, with esthetic brackets, cellular viability by 3,(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide assay (Sigma, St. Louis, Mo) in the macrophage cell line J774 stimulated with interferon gamma. Interferon gamma is a key cytokine in the activation of macrophages, plays an important role in immunologic processes, and also quantifies NO production by these macrophages. METHODS: Well plates were seeded with 2 x 104 J774 cells per well, in a volume of 100 microL, resuspended in Roswell Park Memorial Institute Supplemented Medium 1640. The macrophage cell line J774 was stimulated with interferon gamma. Ceramic, polycarbonate, and polyoxymethylene brackets were added and kept in the culture for 24, 48, or 72 hours in 5% carbon dioxide at 37 degrees C; the control samples did not include brackets. At the end of each incubation period, the supernatant was collected for posterior NO quantification, and the cells were evaluated for cytotoxicity. RESULTS: Cellular viability in all groups was higher at 72 hours than at 24 hours. The final means in the bracket groups did not show significant differences compared with the control group. NO production was significantly greater in all groups at the final time than at the initial time. However, the brackets with the interferon gamma stimulation did not result in greater NO production than did the cells in the control group.


Assuntos
Cerâmica/toxicidade , Materiais Dentários/toxicidade , Interferon gama/farmacologia , Macrófagos/efeitos dos fármacos , Óxido Nítrico/biossíntese , Braquetes Ortodônticos , Cimento de Policarboxilato/toxicidade , Resinas Sintéticas/toxicidade , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Corantes , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/citologia , Teste de Materiais , Camundongos , Óxido Nítrico/análise , Temperatura , Sais de Tetrazólio , Tiazóis , Fatores de Tempo
9.
Am J Orthod Dentofacial Orthop ; 137(2): 247-53, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20152682

RESUMO

INTRODUCTION: Studies show that ceramic brackets are chemically inert in the oral cavity, whereas polycarbonate and polyoxymethylene brackets can degrade, releasing bisphenol-A and formaldehyde, respectively. In addition to the traditional cytotoxicity tests, the study of nitric oxide cellular production stimulated by a specific material has been shown to be a reliable tool for evaluating its cytotoxic potential. METHODS: We aimed to assess cellular viability by MTT (Sigma, St. Louis, Mo): 3,(4,5-dimethylthiazol-2-yl)-2,5diphenyl tetrazolium bromide assay in a murine macrophage cell line J774 with esthetic brackets and quantify nitric oxide production by these macrophages. Cell cultures were evaluated at 3 times: 24, 48, and 72 hours. RESULTS: Cellular viability in all groups was higher at 72 hours compared with 24 hours. This increase was significant in the control and ceramic brackets groups. Final means in the bracket groups showed no significant differences compared with the control group. Nitric oxide production was significantly greater in all groups at final time. There was no significant difference between the final means of the bracket groups and the control group, although polyoxymethylene brackets showed significantly greater means at 24 and 48 hours. CONCLUSIONS: Final means in the bracket groups showed no significant differences compared with the control group.


Assuntos
Materiais Dentários/toxicidade , Macrófagos/metabolismo , Óxido Nítrico/metabolismo , Braquetes Ortodônticos , Animais , Contagem de Células/métodos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Colorimetria/métodos , Materiais Dentários/química , Porcelana Dentária/química , Porcelana Dentária/toxicidade , Formazans , Macrófagos/efeitos dos fármacos , Teste de Materiais/métodos , Camundongos , Cimento de Policarboxilato/química , Cimento de Policarboxilato/toxicidade , Resinas Sintéticas/química , Resinas Sintéticas/toxicidade , Estatísticas não Paramétricas , Sais de Tetrazólio
10.
J Oral Rehabil ; 33(12): 912-7, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17168933

RESUMO

Glass-ionomer cements are widely used in dentistry as restorative materials and adhesives for composite restorations. A number of genotoxicity studies have been conducted using these materials with results conflicting so far. Thus, the approach was aimed to look at the genotoxic and cytotoxic potential of three different glass-ionomer cements available commercially (Ketac Cem, Ketac Molar and Vitrebond) by the single cell gel (comet) assay and trypan blue exclusion test, respectively. For this, such materials were exposed to mouse lymphoma cells in vitro for 1 h at 37 degrees C. Data were assessed by Kruskall-Wallis non-parametric test. The results showed that all powders assayed did not show genotoxic effects. On the other hand, the liquid from Vitrebond at 0.1% dilution caused an increase of DNA injury. Significant statistically differences (P < 0.05) in cytotoxicity provoked by all powders tested were observed for exposure at 1,000 micro g mL(-1) concentration and 100 micro g mL(-1) for Ketac Molar. With respect to liquids of glass-ionomer cements evaluated, the major toxic effect on cell viability was produced at 1%, beginning at the dilution of 0.5% for Vitrebond. Taken together, these results support the notion that some components of glass-ionomer cements show both genotoxic and cytotoxic effects in higher concentrations.


Assuntos
Dano ao DNA , Materiais Dentários/toxicidade , Cimentos de Ionômeros de Vidro/toxicidade , Animais , Sobrevivência Celular/efeitos dos fármacos , Ensaio Cometa , Leucemia L5178 , Óxido de Magnésio/toxicidade , Teste de Materiais , Camundongos , Cimento de Policarboxilato/toxicidade , Estatísticas não Paramétricas , Azul Tripano , Óxido de Zinco/toxicidade
11.
Artigo em Inglês | MEDLINE | ID: mdl-12539035

RESUMO

OBJECTIVE: This in vitro study characterized the hemolysis and cytotoxicity of ZUT, an experimental glass ionomer cement (GIC) sealer with an added antimicrobial-containing zeolite (0.2% Zeomic w/w). STUDY DESIGN: ZUT, Ketac-Cem (GIC component of ZUT), Ketac-Endo, and two AH 26 sealer formulations were tested at various times after mixing. Hemolysis produced by standardized specimens was determined spectrophotometrically (n = 6/material). Cytotoxicity was assessed by using a Millipore Filter test with a HeLa cell monolayer (n = 10/material). Tests were repeated, and results were analyzed with a one-way analysis of variance (alpha = .05). RESULTS: Disks of AH 26 containing silver produced the most hemolysis of all test groups (P < .0001). Compared to controls, GICs and AH 26 formulations were noncytotoxic at 1 and 6 hours after mixing, respectively (P > .05). Addition of Zeomic did not increase the cytotoxic and hemolytic activity of Ketac-Cem (P > .05). CONCLUSION: Overall results suggest ZUT is less cytotoxic than AH 26 and possesses characteristics similar to the other GIC formulations tested.


Assuntos
Cimentos de Ionômeros de Vidro/toxicidade , Hemólise/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/toxicidade , Zeolitas/toxicidade , Análise de Variância , Bismuto/toxicidade , Combinação de Medicamentos , Resinas Epóxi/toxicidade , Filtração/instrumentação , Células HeLa/efeitos dos fármacos , Humanos , Óxido de Magnésio/toxicidade , Cimento de Policarboxilato/toxicidade , Prata/toxicidade , Titânio/toxicidade , Óxido de Zinco/toxicidade
12.
Toxicol Ind Health ; 15(5): 464-9, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10487357

RESUMO

Acute inhalation of diesel fuel-polycarbonate plastic (DFPP) smoke causes severe lung injury, leading to acute respiratory distress syndrome (ARDS) and death. It has been reported that the initiation of acute lung injury is associated with the activation of pulmonary alveolar macrophages (PAM). To further explore the pathogenesis, alveolar macrophages (AM) of New Zealand rabbits ventilated and exposed to a 60 tidal volume of DFPP smoke in vivo were recovered at 1 h post-smoke. Smoke exposure induced significant increases in both mRNA and protein levels for PAM tumor necrosis factor-alpha (TNF-alpha), when compared to smoke control. Smoke also induced a biphasic response (inhibited at 2 h, enhanced at 24 h after cell isolation) in the production of superoxide (O2-) by PAM. However, aerosolized lazaroid, U75412E (1.6 mg/kg body weight), significantly attenuated smoke-induced expression in AM TNF-alpha at the protein level but not at the mRNA level, and smoke-induced changes in AM production of O2-. This study suggests that highly expressing AM TNF-alpha following smoke may be a key contributor to the cascade that establishes an acute injury process and exacerbates oxidant-derived cell injury. Whereas, the lazaroid may ameliorate smoke-induced lung injury by attenuating AM TNF-alpha release, in addition to its primary antioxidative mechanism.


Assuntos
Antioxidantes/farmacologia , Macrófagos Alveolares/efeitos dos fármacos , Lesão por Inalação de Fumaça/prevenção & controle , Fumaça/efeitos adversos , Esteroides/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Aerossóis/farmacologia , Animais , Líquido da Lavagem Broncoalveolar/citologia , Contagem de Células/efeitos dos fármacos , Células Cultivadas , Meios de Cultivo Condicionados/química , Feminino , Gasolina/toxicidade , Macrófagos Alveolares/metabolismo , Cimento de Policarboxilato/toxicidade , RNA Mensageiro/metabolismo , Coelhos , Explosão Respiratória/efeitos dos fármacos , Lesão por Inalação de Fumaça/metabolismo , Organismos Livres de Patógenos Específicos , Superóxidos/metabolismo , Fator de Necrose Tumoral alfa/genética
13.
Fundam Appl Toxicol ; 7(4): 601-8, 1986 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3803754

RESUMO

Male C3H/HeJ mice were thrice weekly given 25 microliter applications of 0.25, 0.05, or 0.01% (w/w) benzo(a)pyrene (BaP) in acetone, or acetone alone, to clipped dorsal skin from 12 to 14 weeks of age for the remainder of their life spans. There were two groups of 40 mice for each treatment regimen, one group being housed in conventional stainless-steel wire mesh cages and the other in polycarbonate cages with wood shavings held in an enclosed ventilated cabinet. Under both housing conditions, tumor incidence was directly related and latency inversely related to BaP concentration. The time-adjusted incidence of epidermal neoplasms was significantly greater for the groups housed in polycarbonate cages. Mortality rates were directly related to BaP concentration and were significantly enhanced by the polycarbonate-cage housing conditions for the high and intermediate concentrations. Survival patterns for the two acetone control groups were similar. These findings indicate that differences in housing conditions can influence both the incidence and the latency of local neoplasms produced in response to the chronic application of a carcinogen in dermal oncogenesis bioassays.


Assuntos
Benzo(a)pireno/toxicidade , Cimentos Dentários/toxicidade , Cimento de Policarboxilato/toxicidade , Neoplasias Cutâneas/induzido quimicamente , Animais , Peso Corporal/efeitos dos fármacos , Carcinoma/induzido quimicamente , Carcinoma/patologia , Masculino , Camundongos , Camundongos Endogâmicos C3H , Papiloma/induzido quimicamente , Papiloma/patologia , Neoplasias Cutâneas/patologia , Aço Inoxidável
14.
Scand J Dent Res ; 85(6): 471-9, 1977 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22926

RESUMO

A cell culture method has been used to study the effect of zinc phosphate cement (De Trey's Zinc Zement Improved), zinc silicophosphate cement (Fluoro-Thin) and polycarboxylate cement (Durelon) on animal cells. Disks (20 x 1 mm) of the materials were placed in the center of plastic Petri dishes and subsequently incubated with human epithelial cells. Cell multiplication, medium pH and the release of cement constituents were measured. All three cements exhibited a cytotoxic effect, which was most pronounced in the cultures with zinc silicophosphate cement and polycarboxylate cement. The results also indicated that cell growth on the surface of the disks is a more sensitive indicator of cytotoxicity than cell growth around the disks. pH of the medium was only slightly affected in cultures with polycarboxylate cement, whereas a decrease was found in cultures with zinc phosphate cement and especially with zinc silicophosphate cement. A rapid release of phosphate was found in cultures with zinc silicophosphate cement. Zinc was released into the medium from disks of zinc phosphate cement, zinc silicophosphate cement and polycarboxylate cement--exceeding the toxicity level for the present cell line after 24 h. In cultures with zinc silicophosphate cement and polycarboxylate cement the release of fluoride reached toxic levels within the same time interval.


Assuntos
Divisão Celular/efeitos dos fármacos , Cimentos Dentários/toxicidade , Células Cultivadas , Células Epiteliais , Humanos , Concentração de Íons de Hidrogênio , Cimento de Policarboxilato/toxicidade , Cimento de Silicato/toxicidade , Cimento de Fosfato de Zinco/toxicidade
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