In vitro evaluation of the cytotoxicity, mutagenicity and DNA damage induced by particle matter and gaseous emissions from a medium-duty diesel vehicle under real driving conditions using palm oil biodiesel blends.

The influence of palm oil biodiesel content on the cytotoxicity, mutagenicity and genotoxicity of particle- and gas-phase diesel vehicle emissions was investigated. The emissions were collected on-board of a EURO IV diesel truck, fuelled with mixtures of 10% (B10), 20% (B20) and 100% (B100) of palm oil biodiesel, under real driving conditions. Organic extracts of the particulate matter (PM) and gases were characterised for 17 PAH (including EPA priority) and used for the biological assay. Increasing biodiesel content in the fuel mixture results in a decrease in the PM and PAH emission factors, both in the particulate and gas-phase. The majority of the PAH are present in the gas-phase. The mutagenic potencies, in TA98 bacteria, are higher for B20 in both phases, whereas the mutagenicity emission factor, that takes into account the lower emission of PM and PAH, is not significantly different between the fuels. Higher direct mutagenicity (TA98 + S9) is observed in all the tested fuels, indicating the action of carcinogenic compounds other than non-substituted PAH. The gas-phase extracts present higher cytotoxicity and genotoxicity in lung epithelial cell A549, which may be related to the higher PAH content in the gas-phase. The increase in biodiesel content have a different impact on cytotoxicity, being larger in the gas-phase and lower in the particle-phase. This indicates that pulmonary toxicity may be higher for the gaseous emissions, due to the role of different toxic compounds compared to the PM. The adverse biological effects when biodiesel content increases are not consequent with the reduction of the PAH characterised, indicating that other toxic compounds are more relevant. Further investigations to identify these compounds are required in order to update and focus the efforts regarding emission targets and controls.

Polymorphism of nanocrystalline TiO2 prepared in a stagnation flame: formation of the TiO2-II phase.

A metastable "high-pressure" phase known as α-PbO2-type TiO2 or TiO2-II is prepared via a single-step synthesis using a laminar premixed stagnation flame. Three other TiO2 polymorphs, namely anatase, rutile and TiO2-B phases, can also be obtained by tuning the oxygen/fuel ratio. TiO2-II is observed as a mixture with rutile under oxygen-lean flame conditions. To the best of our knowledge, this is the first time that this phase has been identified in flame-synthesised TiO2. The formation of TiO2-II in an atmospheric pressure flame cannot be explained thermodynamically and is hypothesised to be kinetically driven through the oxidation and solid-state transformation of a sub-oxide TiO2-x intermediate. In this scenario, rutile is nucleated from the metastable TiO2-II phase instead of directly from a molten/amorphous state. Mixtures containing three-phase heterojunctions of anatase, rutile, and TiO2-II nanoparticles as prepared here in slightly oxygen-lean flames might be important in photocatalysis due to enhanced electron-hole separation.

Size spectra and source apportionment of fine particulates in tropical urban environment during southwest monsoon season.

In this study, we carried out high time-resolution measurements of particle number concentration and size distribution (5-1000 nm) in Singapore, which represents a tropical urban environment. The measurements were taken during the southwest monsoon season in 2017 using a fast-response differential mobility spectrometer at a sampling rate of 1 Hz. In the measurement, short-lived nucleation events were found prominent at early afternoon because of the abundant incoming radiation that enhances the photochemical reactions in atmosphere. For the first time in the region, a five-factor positive matrix factorization approach was applied to the size spectra data. Based on particle number concentration, two sources within nucleation mode (<30 nm) were resolved and account for 43% of total number concentration, which is higher than the available monitoring data in other big cities. Among the sources, O3-related atmospheric photochemical reactions with peak size at 10-12 nm is a unique factor and prominent in early afternoon nucleation events. The findings of this work can serve as a baseline for assessing influence of local and cross-border airborne emissions during various seasons in the future.

A Randomized Placebo-Controlled N-of-1 Trial: The Effect of Proton Pump Inhibitor in the Management of Gastroesophageal Reflux Disease.

Background: Gastroesophageal reflux disease (GERD) is the most frequent chronic gastrointestinal disorder. It is defined as a condition developed when the reflux of gastric contents causes troublesome symptoms (heartburn and regurgitation). This requires adequate treatment since it can lead to long-term complications including esophagus adenocarcinoma. Proton pump inhibitors (PPI) are generally used to treat GERD due to their high-security profile and efficiency on most patients. However, recurrent reflux despite initial treatment is frequent. N-of-1 trial is a study that allows the identification of the best treatment for each patient. The objective of this study is to compare the efficacy of standard dose with double dosage of esomeprazole, to improve the GERD symptoms in a single patient. Methods: A single-patient trial, placebo-controlled, randomized, double-blind, was carried out from September 25th, 2012, to April 26th, 2013. It included one outpatient at the gastroenterology service in a fourth-level hospital, diagnosed with nonerosive reflux disease (NERD). Yet, his symptoms were heartburn and reflux, and his endoscopic results were normal esophageal mucosa, without hiatal hernia, though pathological pH values. A no-obese male without any tobacco or alcohol usage received esomeprazole 40 mg/day and 40 mg/bid for 24 weeks. A standardized gastroesophageal reflux disease questionnaire (GerdQ) was used weekly to evaluate symptom frequency and severity. The consumption of 90% of the capsules was considered as an adequate treatment adherence. D'agostino-Pearson and Wilcoxon test were used to determine normal or nonnormal distribution and compare both treatments, respectively, both with a significant statistical difference of p < 0.05. Results: The patient completed the study with 96% of adherence. The double dosage of esomeprazole did not improve the control of symptoms compared with the standard dosage. Mean symptomatic score was 9.5±0.5 and 10.2±0.6 for each treatment, respectively (p > 0.05). Conclusion: There was no significant improvement in the patient GERD symptoms increasing the dose of oral esomeprazole during the 6 months of study. N-of-1 trials in chronic pathologies including GERD are recommended due to their potential value as systematic methods that evaluate therapies without strong scientific evidence.

Pólipos gástricos: Aspectos epidemiológicos y su relación con el consumo de bloqueadores de bomba / Gastric polypoid lesions: epidemiological Aspects and your relation with proton pump blockers consumption

OBJETIVOS. Analizar nuestros pacientes con pólipos gástricos con respecto a las características demográficas, histopatológicas, clínicas y endoscópicas, y la relación con el consumo de bloqueadores de bomba.MÉTODOS. Se revisaron retrospectivamente las historias clínicas y los reportes histológicos de los pacientes con pólipos gástricos. Casi todas las lesiones se removieron con pinzas de biopsia o asa de polipectomía. Se contactaron telefónicamente 117 pacientes para determinar si había o no consumo de bloqueadores de bomba y el tiempo de este consumo.RESULTADOS. Se encontraron pólipos en 150 pacientes. En 42 hombres (28 por ciento) y 108 mujeres (72 por ciento) con una edad promedio de 56 años (rango de 18 a 88 años). El síntoma más frecuente fue la dispepsia en 69 pacientes (46 por ciento). Los síntomas se relacionaron más con las anomalías gástricas asociadas que por la presencia de los pólipos. Los pólipos se ubicaron más frecuentemente en el fondo gástrico (39 por ciento), seguido por el antro (35 por ciento). De los 150 pacientes, en 69 (46 por ciento) se encontraron pólipos de 5 mms o menos y sólo 4 fueron pediculados. La frecuencia de los pólipos hiperplásicos, inflamatorios y glándulo-fúndicos fue de 55 por ciento, 18 por ciento y 9 por ciento. Se detectaron 5 pacientes con pólipos adenomatosos, tumores carcinoides en 5, GIST en 5 y otros 12 pacientes con diferentes pólipos epiteliales benignos. Se encontraron seis pacientes con cambios adenomatosos en pólipos hiperplásicos. La evaluación histológica de la mucosa gástrica vecina demostró gastritis crónica en 131 pacientes (87 por ciento) y en 87 (58 por ciento) había infección por helicobacter pylori. El consumo promedio de bloqueadores de bomba fue de 6 meses para las diferentes variantes histológicas excepto para los pólipos carcinoides que tenían un consumo de 20 meses.CONCLUSIONES. Los pólipos hiperplásicos son los pólipos más frecuentemente encontrados y la ubicación más usual fue en el cuerpo y...

Bimodal frequency distribution of estrogen receptor immunohistochemical staining results in breast cancer: an analysis of 825 cases.

Immunohistochemical analysis is used routinely to determine the estrogen receptor (ER) status of breast cancers in paraffin sections. However, lack of standardization has raised concerns that weakly ER+ tumors often are classified erroneously as ER-. To determine the frequency of weakly ER+ tumors, we reviewed ER immunostains of 825 breast cancers. For each case, we estimated the proportion of ER+ tumor cells and also determined an Allred score (which results in scores of 0 or 2 through 8, based on staining intensity and proportion of positive cells). In 817 cases (99.0%), tumor cells showed complete absence of staining or staining in 70% or more of the cells. Similarly, 818 cases (99.2%) exhibited Allred scores of 0 or of 7 or 8. Thus, with the immunohistochemical method used in our laboratory, ER staining is essentially bimodal. The overwhelming majority of breast cancers are either completely ER- or unambiguously ER+, and cases with weak ER immunostaining are rare.