bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of different test models for the assessment of cytotoxicity of composite resins
Authors: Cao Tong , Saw Tzuen Yih , Heng Boon Chin , Liu Hua , Yap Adrian U Jin , Ng Mah Lee 
Published: March 2005

AbstractThis study compared the use of different test models to assess the cytotoxicity of a dental composite. The cytotoxicity of a composite polymerized using two halogen‐based light‐curing units (LCUs) (Max LC and Astralis) and two light‐emitting diode LCUs (E‐light and Freelight) served as the basis of comparison. Disk‐shaped specimens (7 mm diameter, 2 mm high) were fabricated using the four different light sources. The specimens were used in several cytotoxicity test models: direct and indirect contact tests as well as an extract test with an established cell line L‐929. The cells were stained with neutral red after cell‐material contact for 48 h. Neutral red‐stained areas (in mm2, for direct and indirect tests) and absorbance readings (for extract tests) were analysed statistically using ANOVA and the Tukey post hoc test, with P < 0.05 considered to be significantly different. Good correlation between direct and indirect contact tests (r = 0.903) was found. The extract test was the least correlated among the three tests. It was found that the E‐light + Freelight‐cured composite elicited cytotoxicity from the correlated studies. Uncured specimens were most detrimental to the cells in all tests. Our data demonstrated that composite cured with light‐emitting diode LCUs were cytotoxic to L‐929 cells. Different test models were found to give rise to different findings. Thus, a good cell‐material contact method would replicate more closely the physiological situation in vivo. This in turn would give more clinically relevant results. Copyright © 2005 John Wiley & Sons, Ltd.
Lead‐induced changes in human erythrocytes and lymphocytes
Authors: Slobozhanina E. I. , Kozlova N. M. , Lukyanenko L. M. , Oleksiuk O. B. , Gabbianelli R. , Fedeli D. , Caulini G. C. , Falcioni G. 
Published: March 2005

AbstractIn the present work we studied, by chemiluminescence measurements, the influence of lead on the production of reactive oxygen species (ROS) in haemolysates obtained from human erythrocytes incubated in the presence of different concentrations of lead acetate. Moreover, we evaluated the modification of proteins and lipids in human erythrocyte and lymphocyte membranes by using the fluorescence probes N‐(1‐pyrene)maleimide (PM), laurdan and pyrene. No significant changes in chemiluminescence were detected for erythrocytes incubated with 1–10 µM lead acetate for 3 h at 37 °C. By increasing the lead acetate concentration in cell suspensions up to 50 µM for the same incubation time, the percentage of chemiluminescence inhibition was ca. 20%. It was shown that, after incorporating fluorescence probes in the membrane lipid bilayer of erythrocytes and lymphocytes treated with 10 and[sol ]or 50 µM lead acetate, the total fluorescence intensity and the excimer to monomer intensity ratio of PM decreased and the generalized fluorescence polarization of laurdan decreased by 10–15%. The pyrene excimerization coefficient (κex) increased by 20% (in comparison with a magnitude of κex for white membranes isolated from intact erythrocytes) with 6–10 µM lead acetate for 3 h at 37 °C.The data obtained suggest that the effect of low concentrations of lead acetate does not cause production of ROS in erythrocytes in vitro, but can change the physicochemical state of proteins and lipids in erythrocyte and lymphocyte membranes. This effect is important because it influences the enzymatic activity and the functionality of receptors and channels present at the plasma membrane level, thus modulating the molecular composition of the intracellular space and cell functions. Copyright © 2005 John Wiley & Sons, Ltd.
Novel approach for classifying chemicals according to skin sensitizing potency by non‐radioisotopic modification of the local lymph node assay
Authors: Takeyoshi Masahiro , Iida Kenji , Shiraishi Keiji , Hoshuyama Satsuki 
Published: March 2005

AbstractThe murine local lymph node assay (LLNA) is currently recognized as a stand‐alone sensitization test for determining the sensitizing potential of chemicals, and it has the advantage of yielding a quantitative endpoint that can be used to predict the sensitization potency of chemicals. The ec3 has been proposed as a parameter for classifying chemicals according to the sensitization potency. We previously developed a non‐radioisotopic endpoint for the LLNA based on 5‐bromo‐2′‐deoxyuridine (BrdU) incorporation (non‐RI LLNA), and we are proposing a new procedure to predict the sensitization potency of chemicals based on comparisons with known human contact allergens. Nine chemicals (i.e. diphencyclopropenone, p‐phenylenediamine, glutaraldehyde, cinnamicaldehyde, citral, eugenol, isopropyl myristate, propyleneglycol and hexane) categorized as human contact allergen classes 1–5 were tested by the non‐RI LLNA with the following reference allergens: 2,4‐dinitrochlorobenzene (DNCB) as a class 1 human contact allergen, isoeugenol as a class 2 human contact allergen and α‐hexylcinnamic aldehyde (HCA) as a class 3 human contact allergen. Consequently, nine test chemicals were almost assigned to their correct allergen class. The results suggested that the new procedure for non‐RI LLNA can provide correct sensitization potency data. Sensitization potency data are useful for evaluating the sensitization risk to humans of exposure to new chemical products. Accordingly, this approach would be an effective modification of LLNA with regard to its experimental design. Moreover, this procedure can be applied also to the standard LLNA with radioisotopes and to other modifications of the LLNA. Copyright © 2005 John Wiley & Sons, Ltd.
Benefits of combining the sexes when evaluating data from toxicological studies
Authors: Wiklund Stig Johan , Svens Karin , Palm Maud , Holland Tom 
Published: March 2005

AbstractIn the assessment of the safety of a new drug, a large battery of toxicological studies is performed. In toxicological studies it is common practice to analyse the data from the sexes separately. We argue that this is not best practice and that much is to be gained from combining data from both sexes when evaluating studies. The main benefits and arguments in favour of combining the data are:(i)	Improved efficiency, allowing fewer test animals and[sol ]or better precision.(ii)	Other phases of drug development, clinical trials in particular, combine sexes.(iii)	Most substances act similarly on both sexes and most drugs are prescribed without sex differentiation.(iv)	If sex differences are of interest, combined data facilitates the quantification of the difference.(v)	Reduced number of false positive and false negative findings.Although there might be some grounds to analysing the sexes separately, we argue that these are comparatively minor.We do not promote simply pooling the data and neglecting the existence of two sexes when comparing treatment groups. Rather, the analysis of combined data should allow for sex differences, for instance by using stratified procedures or by including a sex factor in a statistical model. We illustrate from real study data where the approach we propose has substantial benefits over traditional methods. A theoretical illustration is provided to quantify mathematically the potential gains and the corresponding sample size reduction, i.e. a reduction of animal use of ca. 50%, that would be possible without impairing the precision of studies. Copyright © 2005 John Wiley & Sons, Ltd.
Legal issues of addiction assessment: the experience with hair testing in Greece
Authors: Savvopoulos M. A. , Pallis E. , Tzatzarakis M. N. , Dialyna I. A. , Tzanakakis G. N. , Tsatsakis A. M. 
Published: March 2005

AbstractThe purpose of this paper is to present Greek law and legislation for crimes and felonies regarding drugs of abuse and the interpretation of hair testing results with respect to Greek law. Details (such as the process, the decision and the competence of the Court, the police record, the indictment, the expert reports, the defendant's individuality, the crimes and the penal confrontal and many others) from legal cases related to toxicomany and its judicial verification were collected and analysed. Laboratory data of cases concerning the laboratory evaluation of toxicomany in addicts and also occasionally the legal course of cases with addict defendants are presented. In four representative cases segmental hair analysis proved that, for as long as the individuals were imprisoned, findings with drug substances corresponding to that period were lesser or practically absent compared with samples corresponding to the time out of prison, which showed increased drug abuse. Hair analysis provides information on chronic exposure rather than acute poisoning. Its detection window varies from some days to months or even years. The procedure that the law lays down in many cases is insufficient and in most cases impossible to abide by. When the medical examiner is not able to decide if the claim of toxicomany is real, segmental hair analysis may be the only way to prove it. In other cases where the medical examiner is able to diagnose the addiction, a segmental hair analysis is necessary because it can show long‐term drug abuse. Copyright © 2005 John Wiley & Sons, Ltd.
Effect of β‐naphthoflavone and phenobarbital on the nephrotoxicity of chlorotrifluoroethylene and 1,1‐dichloro‐2,2‐difluoroethylene in the rat
Authors: Morel Georges , Ban Masarin , Bonnet Pierre , Zissu Danièle , Brondeau Marie‐Thérèse 
Published: March 2005

AbstractThe role of cytochrome P450 activity in the nephrotoxicity of chlorotrifluoroethylene (CTFE) and 1,1‐dichloro‐2,2‐difluoroethylene (DCDFE) was investigated in the male rat. Hepatic cytochrome P450 1A1 and principally P450 2B1[sol ]2 were induced by β‐naphthoflavone and phenobarbital, respectively. Nephrotoxicity was evaluated by investigating urine biochemical parameters, kidney histochemistry and histopathological modifications.Both CTFE and DCDFE induce severe nephrotoxicity in rats after 4 h of exposure to 200 and 100 ppm, respectively. Compared with controls, activity levels of γ‐glutamyltranspeptidase (γGT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and N‐acetyl‐β‐d‐glucosaminidase (NAG) in 24‐h urine were increased similarly, but urinary excretion of glucose, proteins and β2‐microglobulin (β2‐m) and serum urea and creatinine levels were increased. Histopathological and histochemical examinations of kidney sections of CTFE‐ and DCDFE‐exposed rats revealed cellular necrosis and tubular lesions 24 h after exposure.β‐Naphthoflavone‐pretreated rats were afforded some protection against the nephrotoxicity of CTFE and DCDFE. Phenobarbital did not modify DCDFE nephrotoxicity but afforded some protection against CTFE nephrotoxicity. In conclusion, CTFE and DCDFE are strong nephrotoxins. Cytochrome P450 1A1 is implicated in CTFE and DCDFE metabolism and one or several cytochromes induced by phenobarbital are implicated in CTFE metabolism. The P450 cytochromes involved in CTFE and DCDFE metabolism probably constitute detoxication metabolic pathways. The nephrotoxicity of CTFE and DCDFE is therefore subordinated to the cytochrome P450 activity involved in their metabolism. Copyright © 2005 John Wiley & Sons, Ltd.
Pro‐inflammatory effects of Dunkerque city air pollution particulate matter 2.5 in human epithelial lung cells (L132) in culture
Authors: Dagher Zeina , Garçon Guillaume , Gosset Pierre , Ledoux Frédéric , Surpateanu Georgiana , Courcot Dominique , Aboukais Antoine , Puskaric Emile , Shirali Pirouz 
Published: March 2005

AbstractExposure to urban airborne particulate matter (PM) has been associated with adverse health effects. The majority of research articles published on air pollution PM relate to PM10. However, increasing emphasis and stringent regulations have been placed on PM2.5. The mechanisms for PM‐induced adverse health effects are not well understood, but inflammation seems to be of importance. We focused our attention also on the capacity of air pollution PM2.5 to induce cytotoxic and inflammatory responses in human epithelial lung cells (L132) in culture. Particulate matter was collected in Dunkerque, a French seaside city characterized by the proximity of industrial activity and heavy motor vehicle traffic. Size distribution results showed that the cumulative frequency of PM2.5 was 92.15% and their specific surface area was 1 m2 g−1. Inorganic and organic chemicals usually associated with the natural environment but also so‐called anthropogenic elements were found in PM, suggesting that much of the PM was derived from wind‐borne dust from the industrial complex and the heavy diesel motor vehicle. We observed PM concentration‐dependent cytotoxic effects in L132 cells (lc10 = 18.84 µg PM ml−1; lc50 = 75.36 µg PM ml−1). We showed that exposure to Dunkerque City's PM2.5 induced significant increases (in a concentration‐ and time‐dependent manner) in protein secretion and[sol ]or gene expression of inflammatory cytokines (i.e. TNF‐α, IL‐1β, IL‐8, GM‐CSF, IL‐6, TGF‐β1). We hypothesized also that the occurrence of the acute inflammatory response might rely on the capacity of such air pollutants to generate oxidative species, which have been implicated in the stringent regulation of the cytokine network. Hence, we suggest that the development of inflammatory effects that worsen over time stems from the cytotoxicity in Dunkerque City's PM2.5‐exposed L132 cells in culture. Copyright © 2005 John Wiley & Sons, Ltd.
Effect of titanium dioxide on the oxidative metabolism of alveolar macrophages: An experimental study in rats
Authors: Olmedo Daniel G. , Tasat Deborah R. , Guglielmotti María B. , Cabrini Rómulo L. 
Published: March 2005

AbstractMetallic implants of titanium are used therapeutically in biomedicine because of its excellent biocompatibility. However, no metal or alloy is completely inert. We have previously shown that titanium oxide (TiO2) is transported in blood by phagocytic monocytes and deposited in organs such as liver, spleen, and lung 6 months after intraperitoneal injection (ip). Furthermore, it is well known that exposure to metal traces alters the cellular redox status. Thus, the aim of the present study was to determine the presence of titanium in target organs after chronic exposure, assess the potential structural alterations, and evaluate the oxidative metabolism of alveolar macrophages (AM) in the lung. Rats were ip injected with 1.60 g/100 g body wt of TiO2 in saline solution. Organs (liver, spleen, lung) were processed for histological evaluation. Reactive oxygen species (ROS) in AM obtained by bronchoalveolar lavage (BAL) were evaluated using the nitroblue tetrazolium test and quantitative evaluation by digital image analysis. The histological analysis of organs revealed the presence of titanium in the parenchyma of these organs with no associated tissue damage. Although in lung alveolar macrophages TiO2 induced a significant rise in ROS generation, it failed to cause tissue alteration. This finding may be attributed to an adaptive response. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 142–149, 2005
Stress ratio contributes to fatigue crack growth in dentin
Authors: Arola D. , Zheng W. , Sundaram N. , Rouland J.A. 
Published: March 2005

AbstractAn experimental study of fatigue crack growth in dentin was conducted, and the influence of stress ratio (R) on the crack growth rate and mechanisms of cyclic extension were examined. Double Cantilever Beam (DCB) fatigue specimens were sectioned from bovine molars and then subjected to high cycle fatigue loading (105 < N < 106) under hydrated conditions. The evaluation consisted of Mode I loads with stress ratios that ranged from −0.5 to 0.5. The fatigue crack growth rates were measured and used to estimate the crack growth exponent (m) and coefficient (C) according to the Paris Law model. The fatigue crack growth rates for steady‐state extension (Region II) ranged from 1E‐7 to 1E‐4 mm/cycle. It was found that the rate of cyclic extension increased significantly with increasing R, and that the highest average crack growth rate occurred at a stress ratio of 0.5. However, the crack growth exponent decreased with increasing R from an average of 4.6 (R = 0.10) to 2.7 (R = 0.50). The stress intensity threshold for crack growth decreased with increasing R as well. Results from this study suggest that an increase in the cyclic stress ratio facilitates fatigue crack growth in dentin and increases the rate of cyclic extension, both of which are critical concerns in minimizing tooth fractures and maintaining lifelong oral health. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 201–212, 2005
The influence of various occlusal materials on stresses transferred to implant‐supported prostheses and supporting bone: A three‐dimensional finite‐element study
Authors: Sevimay Mujde , Usumez Aslihan , Eskitascıoglu Gurcan 
Published: March 2005

AbstractThe aim of this numerical analysis was to evaluate the amount and localization of stress that occurs with various materials used in implant‐crown design under functional forces. Computer‐aided design techniques and a finite‐element stress analysis method were used for evaluation. A 4.1 × 10‐mm implant placed in the mandibular second premolar area was simulated and analyzed. Simulation and analysis were performed with the use of COSMOS/M software and Pro/Engineer 2000i on a Dual Pentium III 1‐GHz computer. Crown designs were as follows: porcelain fused to noble metal crown, porcelain fused to base metal crown, In‐Ceram porcelain crown, and IPS Empress 2 porcelain crown. A 300‐N vertical force was applied to the centric relation stop points of the crowns. The results of this study indicated that different types of restorative materials play an important role in the amount and distribution of the stresses in the superstructure and the implant. The highest stress values were observed in the IPS Empress 2 porcelain crown design (600 MPa). Porcelain fused to base metal and In‐Ceram framework designs transferred less stress to abutment. Type of restorative materials used in implant crown designs are significant factors in the amount and distribution of the stresses on superstructure and implant under functional forces. Porcelain fused to base metal (149 MPa) and In‐Ceram (173 MPa) crown designs induced higher von Mises stress values within the framework than porcelain fused to noble metal (108 MPa) and IPS Empress 2 (119 MPa) porcelain crown designs. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 73B: 140–147, 2005
Wear analysis of retrieved ceramic‐on‐ceramic articulations in total hip arthroplasty: Femoral head makes contact with the rim of the socket outside of the bearing surface
Authors: Yamamoto Tetsuya , Saito Masanobu , Ueno Masaru , Hananouchi Takehito , Tokugawa Yusuke , Yonenobu Kazuo 
Published: March 2005

AbstractWe investigated articular bearing surfaces retrieved from three patients with ceramic‐on‐ceramic total hip arthroplasties using high‐quality alumina. The duration of implantation was 3.5, 3.0, and 2.5 years, respectively. Dislocation of the hip joint after implantation did not occur in any patients. The retrieved prostheses were examined by stereomicroscopy and scanning electron microscopy (SEM). In the main load‐bearing area, no wear marks were seen in any sockets. However, in all three cases, stripe scars were observed at the rim of the alumina inlay under stereomicroscopy, despite the lack of indentation in the socket and the stem, which suggests impingement. Such scars were not observed on the load‐bearing surface. Under SEM, the scars showed excessive wear, including material excavation, that has not been observed in conventional hip simulator experiments. These findings are similar to those of experiments in which a simulator was programmed to distract the femoral head from the socket. The present results suggest that the femoral head can separate from the socket without neck‐socket impingement in vivo. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Discoloration of dental resin composites after immersion in a series of organic and chemical solutions
Authors: Lee Yong‐Keun , Powers John M. 
Published: March 2005

AbstractThe objective of this study was to evaluate the color change of dental resin composites following a series of immersion treatments, especially in organic substances. The color of four resin composites was measured according to the CIELAB color scale relative to the standard illuminant D65. Color was measured at baseline, and after sequential immersion in the following substances: Step 1, porcine‐liver esterase (a substitute for a salivary esterase); Step 2, organic substances (mucin and serum) and phosphate‐buffered saline (PBS) as a control; Step 3, chemical alteration agents [chlorhexidine (CH) and carbamide peroxide (CP)]; and Step 4, 2% methylene blue. Porcine‐liver esterase caused color changes (ΔE) of 0.7–1.1 from the baseline. Organic substances caused color changes of 0.4–1.8 from the baseline, and color changes in organic substances were not significantly higher than those in PBS (p > 0.05), except for one composite. Combined treatment with mucin (or serum) with CH (or CP) did not produce significantly higher color changes compared to controls (p > 0.05). Mucin‐treated composites showed generally lower methylene blue staining compared to serum and PBS groups. Although combined treatment of organic substances and chemical agents resulted in various discolorations of resin composites, chemical alteration of organic substances did not produce higher color change compared to PBS controls. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Corrosion behavior of cast Ti‐6Al‐4V alloyed with Cu
Authors: Koike Marie , Cai Zhuo , Oda Yutaka , Hattori Masayuki , Fujii Hiroyuki , Okabe Toru 
Published: March 2005

AbstractIt has recently been found that alloying with copper improved the inherently poor grindability and wear resistance of titanium. This study characterized the corrosion behavior of cast Ti‐6Al‐4V alloyed with copper. Alloys (0.9 or 3.5 mass % Cu) were cast with the use of a magnesia‐based investment in a centrifugal casting machine. Three specimen surfaces were tested: ground, sandblasted, and as cast. Commercially pure titanium and Ti‐6Al‐4V served as controls. Open‐circuit potential measurement, linear polarization, and potentiodynamic cathodic polarization were performed in aerated (air + 10% CO2) modified Tani‐Zucchi synthetic saliva at 37°C. Potentiodynamic anodic polarization was conducted in the same medium deaerated by N2 + 10% CO2. Polarization resistance (Rp), Tafel slopes, and corrosion current density (Icorr) were determined. A passive region occurred for the alloy specimens with ground and sandblasted surfaces, as for CP Ti. However, no passivation was observed on the as‐cast alloys or on CP Ti. There were significant differences among all metals tested for Rp and Icorr and significantly higher Rp and lower Icorr values for CP Ti compared to Ti‐6Al‐4V or the alloys with Cu. Alloying up to 3.5 mass % Cu to Ti‐6Al‐4V did not change the corrosion behavior. Specimens with ground or sandblasted surfaces were superior to specimens with as‐cast surfaces. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater