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The study is devoted to pack-powder boriding of ASTM A709 steel in a powder mixture containing boron carbide, potassium fluoroborate and silicon carbide. This surface hardening process is conducted between 1123 and 1273 K for from 2 to 8 h. The formed diiron boride layers are studied by different techniques (scanning electron microscopy, x-ray diffraction (XRD) analysis, glow discharge optical emission spectroscopy (GDOES), Vickers microhardness testing, surface profilometry, Rockwell-C indentation cohesion and pin-on-disc tests). Kinetically, an integral-method-based approach is applied to calculate the boron diffusivities in Fe2B. The activation energy of the process is deduced and compared to reported data. The same model is ultimately verified by comparing the empirical values of the thickness of the Fe2B layers obtained at 1223 K and 1273 K for 9 h and the predicted values. [ABSTRACT FROM AUTHOR]

Objective: To assess the added value of diffusion-weighted imaging (DWI) to high-resolution T2-weighted sequences (HRT2w) in MRI detection of extramural venous infiltration (EMVI), according to the previous experience of radiologists. Methods: A cross-sectional study of a retrospective database including 1.5 T MRI records from 100 patients with biopsy-proven rectal cancer (2011–2016; 75 male/25 female, average 63 y/o), which included primary staging (54) and post-chemoradiotherapy follow-up MRIs (46). The reference standard was histology of surgical specimens. All cases were individually blindly reviewed by ten radiologists: three specialists in abdominal radiology, three specialized in different areas and four residents. In each case, the presence of EMVI was assessed twice: first, using just HRT2w; second, with DWI added to HRT2w. The results were pooled by experience, analyzing sensitivity, specificity, accuracy (area under ROC curve), likelihood ratios, predictive values and overstaging/understaging. Results: Addition of DWI improved diagnostic performance by specialists radiologists, particularly post-chemoradiotherapy (accuracy 0.74–0.84; positive likelihood ratio 3.9–9.1; overstaging 16–8%), less so at primary staging (specificity 76–87.2%; overstaging 21–11%). Non-specialist radiologists also improved, but only at primary staging (accuracy 0.59–0.63). Residents showed small changes, except for notably increased sensitivity in both primary staging (35.7–43%) and post-chemoradiotherapy (41.7–58.3%) staging, at the expense of increased overstaging. Conclusions: The addition of DWI improved the diagnostic performance of EMVI by experienced radiologists, downgrading overstaging, especially in post-chemoradiotherapy follow-up. It resulted in fewer changes for inexperienced radiologists (enhanced primary staging) and residents (increased sensitivity). [ABSTRACT FROM AUTHOR]

In this work, we have grown nanostructured vanadium dioxide (VO2) thin films by a spray pyrolysis coating method on glass pre-heated substrates at 450 °C and studied their optical and electronic properties. As-prepared film structure and morphology, with a thickness of ~ 400 nm, were examined by X-ray diffraction, Raman spectra, and atomic force microscopy (AFM), thus revealing a polycrystalline monoclinic M1 phase. On the other hand, the electrical resistance was measured as a function of the temperature in the range of 25 to 100 °C where a clear transition from the M1 phase at T = 25 °C to the metallic one (conductive phase) at ~ 60 °C was observed. This also confirms the stability of the M1 phase for T < 60 °C. The electronic properties and band structure were additionally investigated by the local density approximation (LDA) using the first principle of the Korringa-Kohn-Rostroker (KKR). As a result, our material showed a magnetic property, specifically an antiferromagnetic stabilization of the M1 phase. [ABSTRACT FROM AUTHOR]

Purpose: In this paper we study the quality of life (QoL) of elderly breast cancer patients receiving endocrine treatment (ET). More QoL data on elderly patients treated with ET are needed. Our aims are to study QoL in early-stage breast cancer patients throughout the treatment period and compare the QoL of ET groups. Methods: 148 patients > 65 years who began ET with either tamoxifen or aromatase inhibitor (AI) completed the EORTC QLQ-C30 and QLQ-BR23 and the Interview for Deterioration in Daily Living Activities in Dementia (IDDD) questionnaires three times over 3 years of ET. Linear mixed-effect models were used to evaluate longitudinal QoL changes. ET group comparisons were conducted after 3 years of treatment via ANCOVA adjusted by basal QoL. Results: QoL scores were high (> 80/100 points) in most QoL areas, with moderate limitations (> 30) in sexual functioning and enjoyment and in future perspective. After 3 years of ET, four QoL areas improved (< 6 points) compared to baseline and 3-month assessments. Hot flushes worsened (8 points) at the 3-month assessment but by 3 years had recovered. AI patients showed more hot flushes, pain and diarrhea and less sexual enjoyment than tamoxifen patients after 3 years of ET (differences 3–12 points). Conclusions: Results indicate that elderly early-stage breast cancer patients adapted well to their disease and ET treatment over the 3 years. Few QoL differences were observed between ET groups. [ABSTRACT FROM AUTHOR]

Purpose: Recent advances in genomics offer a smart option for predicting future risk of disease and prognosis. The objective of this study was to examine the prognostic value in heart failure (HF) patients, of a series of single nucleotide polymorphisms (SNPs). Methods: A selection of 192 SNPs found to be related with obesity, body mass index, circulating lipids or cardiovascular diseases were genotyped in 191 patients with HF. Anthropometrical and clinical variables were collected for each patient, and death and readmission by HF were registered as the primary endpoint. Results: A total of 53 events were registered during a follow-up period of 438 (263–1077) days (median (IQR)). Eight SNPs strongly related to obesity and HF prognosis were selected as possible prognostic variables. From these, rs10189761 and rs737337 variants were independently associated with HF prognosis (HR 2.295 (1.287–4.089, 95% CI); p = 0.005), whereas rs10423928, rs1800437, rs737337 and rs9351814 were related with bad prognosis only in obese patients (HR 2.142 (1.438–3.192, 95% CI); p = 0.00018). Combined scores of the genomic variants were highly predictive of poor prognosis. Conclusions: SNPs rs10189761 and rs737337 were identified, for the first time, as independent predictors of major clinical outcomes in patients with HF. The data suggests an additive predictive value of these SNPs for a HF prognosis. In particular for obese patients, SNPs rs10423928, rs1800437, rs737337 and rs9351814 were related with a bad prognosis. Combined scores weighting the risk of each genomic variant could effect interesting new tools to stratify the prognostic risk of HF patients. [ABSTRACT FROM AUTHOR]

In the current study, the powder-pack boriding was applied to the AISI 12L14 steel in the temperature range 1123 K to 1273 K for an exposure time between 2 and 8 hours. The produced boride layer was composed of Fe2B with a sawtooth morphology. A diffusion model based on the integral method was applied to investigate the growth kinetics of Fe2B layers. As a main result, the boron diffusion coefficients in Fe2B were estimated by considering the principle of mass balance at the (Fe2B/substrate) interface with an inclusion of boride incubation times. The value of activation energy for boron diffusion in AISI 12L14 steel was estimated as 165 kJ mol−1 and compared with other values of activation energy found in the literature. An experimental validation of the present model was made by using four different boriding conditions. Furthermore, the Rockwell-C adhesion test was employed to assess the cohesion of boride layers to the base metal. The scratch and pin-on-disc tests were also carried out to analyze the effect of boriding on wear behavior of AISI 12L14 steel. [ABSTRACT FROM AUTHOR]

In this work, the effect of hydrogen flow and thermal annealing on the compositional and optical properties of non-stoichiometric silicon oxide (SiO x) films with embedded silicon nanocrystals is reported. The SiO films are obtained by hot filament chemical vapor deposition technique at three different hydrogen flow levels, namely, 50 sccm, 100 sccm, and 150 sccm. The SiO x films are characterized by different techniques. It is found by x-ray photoelectron spectroscopy (XPS) that with increasing hydrogen flow, the SiO x films contain higher silicon (Si) concentration. When the hydrogen flow decreases, the absorption edge of the as-grown SiO x films, as obtained from the transmittance spectra, shifts from 300 nm to 500 nm, and this opens the possibility of band gap tuning. Increasing the hydrogen flow level in turn means that the SiO x films contain higher Si concentration, as confirmed by the XPS profile composition measured in the SiO x films. After thermal annealing, the SiO x films transmittance spectra showed a further shift of the absorption edge toward larger wavelengths. The Fourier transform infrared (FTIR) spectroscopy reveals film composition changes induced by the hydrogen flow variations. In addition, the FTIR spectra reveal the bands attributed to the hydrogen presence in the as-grown SiO x films. The bands become more intense with increasing hydrogen flow, but they rapidly disappear after the thermal annealing. The as-grown SiO x films exhibit wide band photoluminescence (PL) spectra with the main components at 688 nm, 750 nm, and 825 nm. The SiO x film deposited at 100 sccm hydrogen flow level shows the strongest PL intensity. According to PL results, the thermal annealing of the SiO x films generates the PL quenching in all samples due to hydrogen evaporation. The defects such as OH and Si-H groups in the as-grown SiOx films not only modify the optical band gap structure, but they also play the role of passivating non-radiative defects, which enhances the PL emission. [ABSTRACT FROM AUTHOR]

In this study, the growth kinetics of nitride layers that develop during the powder-pack nitriding process on the surface of ARMCO pure iron was estimated. The powder-pack nitriding of pure iron was performed according to the Pulnieren (H.E.F. Durferrit) method using a 'Pulnier' powder and an activator, at 798-848 K with different exposure times (2-12 h) for each temperature. In addition, for the entire set of nitriding conditions, three different activator/'Pulnier' powder ratios (0.20, 0.25, and 0.35) were used to evaluate the activation level during the growth of nitride layers. The kinetics of the nitride layers over the surface of ARMCO pure iron were estimated by two mathematical approaches, that consider the mass balance equations at the growth interphases. The resulting expressions for the effective diffusion coefficients in the nitride layers were evaluated as a function of nitriding temperatures and activator/'Pulnier' powder ratio. Finally, based on the experimental parameters ascribed to the powder-pack nitriding process, two expressions were proposed to estimate the nitride layer thicknesses at 798 and 823 K after 9 h of exposure for each temperature, to validate the diffusion models used in this work. [ABSTRACT FROM AUTHOR]

Purpose: We analysed the status of current water and sediment management practices in six deltas and estuaries, which were part of the European DELTANET, INTERREG-funded network. Materials and methods: These systems-the Danube, Ebro and Vistula deltas and the Elbe, Minho and Severn estuaries-represent different geographic regions of Europe. This enables comparison between the sites' approaches to common coastal issues, notably those associated with sediment budgets, contamination and flood risk. Based on documentary analysis, workshop events and expert discussion, we employ a simple classification scheme to distinguish between levels of risk from these aspects. Results: We suggest that flood risk is the most significant risk, followed by upstream sediment retention and sediment aggradation. Chemical contamination, though less severe, is not unimportant. Key management issues include a lack of environmental quality standards for sediment and suspended particulate matter, as well as the limited deployment of monitoring programmes, regular sediment sampling and associated chemical analyses. Conclusions: These include both general and specific recommendations. Within these, the limited scope of integrated plans that aim for sustainability of the respective systems is highlighted. It is suggested that these do not challenge traditional, classical engineering approaches sufficiently. Nor do they address the origin of many environmental problems, especially those which are closely linked to short-term political and economic priorities. [ABSTRACT FROM AUTHOR]

The prevalence of multidrug-resistant (MDR) Pseudomonas aeruginosa has increased over the past decade and a significant rise in these isolates in ventilator-associated pneumonia (VAP) has been observed. However, the impact of MDR on VAP outcome has not been analysed in depth. We investigated the risk factors for early and crude mortality in a retrospective study of microbiologically and clinically documented VAP. Ninety-one VAP episodes in 83 patients were included, 31 caused by susceptible P. aeruginosa and 60 by MDR strains, of which 42 (70 %) were extensively drug-resistant (XDR) P. aeruginosa. Thirteen episodes concomitantly presented P. aeruginosa bacteraemia, in seven of which the origin was the respiratory tract. Whereas susceptible P. aeruginosa episodes were more likely than MDR episodes to receive adequate empirical (68 % vs. 30 %; p < 0.001) and definitive antimicrobial therapy (96 % vs. 50 %; p < 0.001), susceptible P. aeruginosa VAP presented a trend towards early mortality (29 % vs. 15 %; p = 0.06). A logistic regression model with early mortality as the dependent variable identified multiorgan dysfunction syndrome (MODS) [odds ratio (OR) 10.4; 95 % confidence interval (CI) 1.7-63.5; p = 0.01] and inadequate antibiotic therapy (OR 4.27; 95 % CI 0.98-18.4; p = 0.052) as independent risk factors for early mortality. A similar analysis identified MODS (OR 4.31; 95 % CI 1.14-16.2; p = 0.03) as the only independent predictor of crude mortality. The severity of acute illness clinical presentation was the main predictor of mortality. Despite adequate antibiotic therapy, susceptible P. aeruginosa seems to cause major early mortality. Although adequate therapy is essential to treat VAP, the severity of acute illness is a more important factor than drug resistance. [ABSTRACT FROM AUTHOR]

Several studies have suggested that resistance determinants usually reduce virulence. However, their contribution to decrease bloodstream infections is unclear. Our aim was to identify risk factors of extensively drug-resistant (XDR) Pseudomonas aeruginosa (PA) bacteremia and to assess the prevalence of XDR-PA bacteremia. A retrospective study of PA bloodstream infections in our patient population with at least one clinical sample isolate due to PA (2006-2007) was carried out. A total of 2,131 patients with PA clinical samples were detected. Among 1,657 patients with susceptible-PA isolates, 95 developed PA-susceptible bacteremia. Concomitantly, among 474 patients with multidrug-resistant (MDR)-PA isolates, 265 with XDR-PA, and 209 with non-XDR MDR-PA, 43 developed XDR-PA bacteremia and 13 non-XDR MDR-PA bacteremia, respectively. Pulsed-field gel electrophoresis (PFGE) revealed the clonal nature of the two predominant XDR-PA phenotypes and genetic heterogeneity in non-XDR MDR-PA phenotypes. The proportion of XDR-PA bacteremia was higher than the proportion of bacteremia in the susceptible-PA population (16 % vs. 6 %; p < 0.001). A logistic regression model identified prior exposure to fluoroquinolones [odds ratio (OR) 2.80; 95 % confidence interval (CI) 1.02 to 7.70] as the independent variable associated with XDR-PA bacteremia. Our study suggests that XDR-PA strains have a greater ability to develop bacteremia. It remains unclear as to whether this invasive capacity depends on clonal traits or on other virulence determinants. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the risk factors for, and the clinical relevance of, faecal carriage by extended-spectrum β-lactamase producing Escherichia coli (ESBL-EC) in neutropenic cancer patients (NCP). An observational prospective multicentre cohort study was conducted over 2 years at two teaching hospitals. Patients with acute leukaemia or undergoing stem cell transplantation were included during neutropenia episodes. Rectal swabs were obtained at hospital admission and weekly thereafter until discharge or death. ESBL-EC colonized episodes were compared with non-colonized episodes. ESBL-EC strains were studied by PCR and isoelectric focusing, and molecular typing was performed by pulsed field gel electrophoresis (PFGE). Among 217 episodes of neutropenia, the prevalence of ESBL-EC faecal carriage was 29% (14% at hospital admission). Multivariate analysis identified previous antibiotics as the only independent risk factor for ESBL-EC faecal colonization (OR 5.38; 95% CI 2.79-10.39). Analysis of ESBL-EC isolates revealed a polyclonal distribution with CTX-M predominance (81.3%). E. coli bacteraemia was mainly caused by non-ESBL producing strains and its rate was similar in both groups (13% vs. 11%). We found no association between ESBL-EC carriage and an increased risk of ESBL-EC bacteremia or a negative influence on other clinical outcomes, including length of hospitalisation, early and overall mortality rates. ESBL-EC faecal colonization is frequent in NCP but difficult to identify by epidemiological or clinical features on presentation. Prior antibiotic therapy is the major associated risk factor. In this setting colonization does not appear to have a significant clinical relevance. Thus, routine testing for ESBL-EC faecal carriage does not seem to be beneficial. [ABSTRACT FROM AUTHOR]

The effects of the chemical heat treatments of a semianthracite char (AC) on the textural properties and the gasification in air they are investigated. Sample AC first was treated with the LiCl/KCl mixture or the mixture formed by LiCl/IKCl and a metallic oxide, M n = 1, 2O (MgO, CaO, FeO, CoO, NiO, Cu2O or ZnO) at 743, 873 or 1173 K and products obtained they were then washings carefully with water distilled. The information on the textural modifications was deduced of isotherms of CO2 adsorption to 273 K. The reactivity tests were taken to the temperature 808, 823 and 838 K. As resulting from the AC treatments, on developed the microporosity and on increase the air reactivity, in particular, the first effect is greater whim the used mixture went LiCl/KCl/CoO at 1173 K and the second effect are greater when the used mixture went LiCl/KCl/Cu2O at 1173 K. [ABSTRACT FROM AUTHOR]

The EC-5 is the European Structural Standard which develops the design of timber structures. One of its principal aims is to give the engineers the rules to design the connections that are used in these kind of structures. Dowel-type fasteners are one of the most extended kind of joints that can appear, and they work in single or in double shear. The focus of this research is to study the design stresses in this last case. The results obtained using the rules included in the official standard will be compared with those arising from the finite element method. The interaction between stresses and other variables such as geometry, section and material will be presented, as well as an analysis of the results. [ABSTRACT FROM AUTHOR]

We investigated the association between urinary tract infections (UTIs) and transitional cell carcinoma of the bladder in a population-based case-control study in Los Angeles covering 1586 cases and age-, gender-, and race-matched neighbourhood controls. A history of bladder infection was associated with a reduced risk of bladder cancer among women (odds ratio (OR), 0.66; 95% confidence interval (CI), 0.46-0.96). No effect was found in men, perhaps due to power limitations. A greater reduction in bladder cancer risk was observed among women with multiple infections (OR, 0.37; 95% CI, 0.18-0.78). Exclusion of subjects with a history of diabetes, kidney or bladder stones did not change the inverse association. A history of kidney infections was not associated with bladder cancer risk, but there was a weak association between a history of other UTIs and slightly increased risk among men. Our results suggest that a history of bladder infection is associated with a reduced risk of bladder cancer among women. Cytotoxicity from antibiotics commonly used to treat bladder infections is proposed as one possible explanation. [ABSTRACT FROM AUTHOR]

A series of Au/TiO2 samples with gold loadings ranging from 0.11% to 1.26% have been prepared by deposition–precipitation, characterised by means of XRD, SBET, XRF, TEM, XPS and DR UV–Vis techniques and tested in the gaseous CO oxidation and photocatalytic degradation of phenol in aqueous media. The catalytic performances of the solids on both reactions depend on the gold content. Besides this, the gold particle size plays a determinant role in the catalytic activity for the CO reaction, but apparently its influence on the photocatalytic activity appears to be negligible and only very small gold particles seem to participate on the photocatalytic process. On the other hand, the electronic properties of the solids, measured by its band gap energy, are a key factor in the photochemical activity but do not have a clear influence in the CO oxidation reaction. [ABSTRACT FROM AUTHOR]

We investigated the effects of individual fatty acids on breast cancer in a prospective study of 35?298 Singapore Chinese women aged 45-74 years, who were enrolled during April 1993 to December 1998 (The Singapore Chinese Health Study). At recruitment, each study subject was administered, in-person, a validated, semiquantitative food frequency questionnaire consisting of 165 food and beverage items. As of December 31, 2000, 314 incident cases of breast cancer had occurred. We used the Cox regression methods to examine individual fatty acids in relation to breast cancer risk, with adjustment for age at baseline interview, year of interview, dialect group, level of education, daily alcohol drinking, number of live births, age when menstrual periods became regular, and family history of breast cancer. Consumption of saturated, monounsaturated or polyunsaturated fat overall was unrelated to risk. On the other hand, high levels of dietary n-3 fatty acids from fish/shellfish (marine n-3 fatty acids) were significantly associated with reduced risk. Relative to the lowest quartile of intake, individuals in the higher three quartiles exhibited a 26% reduction in risk (relative risk (RR)=0.74, 95% confidence interval (CI)=0.58, 0.94)); RRs were similar across the top three quartiles of intake (0.75, 0.75, 0.72, respectively). Overall, there was no association between n-6 fatty acids and breast cancer risk. However, among subjects who consumed low levels of marine n-3 fatty acids (lowest quartile of intake), a statistically significant increase in risk was observed in individuals belonging to the highest vs the lowest quartile of n-6 fatty acid consumption (RR=1.87, 95% CI=1.06-3.27); the corresponding RR for advanced breast cancer was 2.45 (95% CI=1.20-4.97, P for trend=0.01). To our knowledge, these are the first prospective findings linking the intake of marine n-3 fatty acids to breast cancer protection.British Journal of Cancer (2003) 89, 1686-1692. doi:10.1038/sj.bjc.6601340 www.bjcancer.com [ABSTRACT FROM AUTHOR]

Inclusion of phenacetin among 'proven' human carcinogens by the IARC in 1987, raised concerns about the carcinogenic potential of acetaminophen, its major metabolite. Acetaminophen has been implicated as a possible causal agent in the development of cancer of the renal pelvis. The bladder and renal pelvis, which derive from the same embryological structure, share the same transitional type of epithelium. Past studies have been inconclusive on the possible relationship among these analgesics and bladder cancer but no large, highly detailed study of this association has been conducted. A population-based case-control study conducted in Los Angeles, California, involved 1514 incident bladder cancer cases and an equal number of controls who were matched to the index cases by sex, date of birth (within 5 years) and race. Detailed information on medication use and prior medical conditions was collected through in-person interviews. Regular use of analgesics was not associated with an increased risk of bladder cancer in either men or women. In fact, compared with non- or irregular users, regular analgesic users were at a decreased risk of bladder cancer overall (odds ratio (OR) = 0.81, 95% confidence interval (CI) = 0.68-0.96). However, there were clear differences in both the direction and strength of the associations between the different formulation classes of analgesics and bladder cancer risk. Intake of phenacetin was positively related to bladder cancer risk in a dose-dependent manner while intake of its major metabolite in humans, acetaminophen, was unrelated to risk. Intake of all classes of NSAIDs, except pyrazolon derivatives, were negatively associated with bladder cancer risk, with suggestive evidence that the protective effect varies in strength by subcategories of formulation. Acetic acids seemed to exhibit the strongest protective effect, whereas aspirin/other salicylic acids and oxicam showed the weakest protection. [ABSTRACT FROM AUTHOR]

Phenacetin-based analgesics have been linked to the development of renal pelvis cancer and renal cell carcinoma (RCC). The relationship between non-phenacetin types of analgesics and kidney cancer is less clear, although laboratory evidence suggests that these drugs possess carcinogenic potential. A population-based case-control study involving 1204 non-Asian RCC patients aged 25-74 and an equal number of sex-, age- and race-matched neighbourhood controls was conducted in Los Angeles, California, to investigate the relationship between sustained use of analgesics and risk of RCC according to major formulation categories. Detailed information on medical and medication histories, and other lifestyle factors was collected through in-person interviews. Regular use of analgesics was a significant risk factor for RCC in both men and women (odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.4-1.9 for both sexes combined). Risks were elevated across all four major classes of analgesics (aspirin, non-steroidal anti-inflammatory agents other than aspirin, acetaminophen and phenacetin). Within each class of analgesics, there was statistically significant increasing risk with increasing level of exposure. Although there was some minor variability by major class of formulation, in general individuals in the highest exposure categories exhibited approximately 2.5-fold increase in risk relative to non- or irregular users of analgesics. Subjects who took one regular-strength (i.e. 325 mg) aspirin a day or less for cardiovascular disease prevention were not at an increased risk of RCC (OR = 0.9, 95% CI = 0.6-1.4). [ABSTRACT FROM AUTHOR]

The article presents a case study of a 64-year-old man with acute distress respiratory syndrome (ADRS) and examines topics including complications during venovenous extracorporeal membrane oxygenation (ECMO), the role of transesophageal echocardiography (TEE) technique, and cannulation.

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The aim of this study was to see whether aluminum (Al) and lead (Pb) salts are toxic for cultured human fibroblasts under different experimental conditions, in the controllable situation offered by cell cultures. Cell survival and membrane lipid peroxidation served as markers of Al and Pb toxicity. Evaluation of the living cells was carried out using a colorimetric method, the mitochondrial reduction of 1-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Lipoperoxidation assay was performed on whole cell homogenates by measuring thiobarbituric acid-reactive substances (TBARS) produced after incubation with ascorbic acid-ferrous sulfate. Al(III) and Pb(II) salts (300 μ M) produce a considerable decrease in cell survival after an exposure period of 4 d, evident with the three fetal calf serum concentrations in the culture media: 2, 5, and 10%. Taking into account in vitro cell aging, the cytotoxic effects of Al(III) and Pb(II) are greater in senescent fibroblasts than in young cells. Lead-induced cytotoxicity is higher than Al-induced cytotoxicity. A mechanism that contributes to cellular toxicity is membrane lipid peroxidation; our results demonstrate that Al(III) and Pb(II) ions, 400 μ M, exert an antioxidant-like effect or a pro-oxidant action on cell membranes depending on exposure time. We describe significant increases in TBARS formation associated with the presence of 400 μ M Al(III) or Pb(II) salts in the culture media. Our study also revealed that these heavy metals induce a cell age-dependent action on membrane lipoperoxidation that is greater in senescent fibroblasts and this could have severe consequences for maintenance of cellular integrity. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses a study that identifies two nonsense mutations in families with Brazilian lynch syndrome.