Tumor circadian clock strength influences metastatic potential and predicts patient prognosis in luminal A breast cancer.

Studies in shift workers and model organisms link circadian disruption to breast cancer. However, molecular circadian rhythms in noncancerous and cancerous human breast tissues and their clinical relevance are largely unknown. We reconstructed rhythms informatically, integrating locally collected, time-stamped biopsies with public datasets. For noncancerous breast tissue, inflammatory, epithelial-mesenchymal transition (EMT), and estrogen responsiveness pathways show circadian modulation. Among tumors, clock correlation analysis demonstrates subtype-specific changes in circadian organization. Luminal A organoids and informatic ordering of luminal A samples exhibit continued, albeit dampened and reprogrammed rhythms. However, CYCLOPS magnitude, a measure of global rhythm strength, varied widely among luminal A samples. Cycling of EMT pathway genes was markedly increased in high-magnitude luminal A tumors. Surprisingly, patients with high-magnitude tumors had reduced 5-y survival. Correspondingly, 3D luminal A cultures show reduced invasion following molecular clock disruption. This study links subtype-specific circadian disruption in breast cancer to EMT, metastatic potential, and prognosis.

Comparative analysis of the jaw apparatus of three marine annelids using scanning electron microscopy: Microstructure and elemental composition.

Polychaeta are highly diversified invertebrates that inhabit marine, brackish or freshwater environments. They have acquired a unique range of adaptative features for securing food. However, the jaw apparatus may reveal not only defence and predation mechanisms, but also its relation to environmental chemistry. The present work compared the structure and chemical profile of the jaws of different estuarine Polychaeta: Nephtys hombergii (Nephtyidae), Hediste diversicolor (Nereididae) and Glycera alba (Glyceridae) using Scanning Electron Microscopy (SEM) and Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX). Analyses revealed that N. hombergii possesses a muscular jawless proboscis with terminal sensorial papillae for detecting prey, whereas the G. alba proboscis exhibits four delicately sharp jaws with perforations for venom delivery and H. diversicolor bears two blunt denticulated jaws to grasp a wide variety of food items. Melanin and metals like copper provide hardness to the slender jaws of Glycera, while, in the absence of heavier metallic elements, halogens contribute to H. diversicolor jaws robustness. The more specific chemistry of the jaws of glycerids is associated with its more refined venom injection, whereas Hediste is an opportunistic omnivore and Nepthys an agile forager. Altogether, the chemistry of jaws is an adaptive feature for feeding, locomotion and even resilience to complex and often adverse chemical profiles of estuaries.

Quantitative live imaging of Venus::BMAL1 in a mouse model reveals complex dynamics of the master circadian clock regulator.

Evolutionarily conserved circadian clocks generate 24-hour rhythms in physiology and behaviour that adapt organisms to their daily and seasonal environments. In mammals, the suprachiasmatic nucleus (SCN) of the hypothalamus is the principal co-ordinator of the cell-autonomous clocks distributed across all major tissues. The importance of robust daily rhythms is highlighted by experimental and epidemiological associations between circadian disruption and human diseases. BMAL1 (a bHLH-PAS domain-containing transcription factor) is the master positive regulator within the transcriptional-translational feedback loops (TTFLs) that cell-autonomously define circadian time. It drives transcription of the negative regulators Period and Cryptochrome alongside numerous clock output genes, and thereby powers circadian time-keeping. Because deletion of Bmal1 alone is sufficient to eliminate circadian rhythms in cells and the whole animal it has been widely used as a model for molecular disruption of circadian rhythms, revealing essential, tissue-specific roles of BMAL1 in, for example, the brain, liver and the musculoskeletal system. Moreover, BMAL1 has clock-independent functions that influence ageing and protein translation. Despite the essential role of BMAL1 in circadian time-keeping, direct measures of its intra-cellular behaviour are still lacking. To fill this knowledge-gap, we used CRISPR Cas9 to generate a mouse expressing a knock-in fluorescent fusion of endogenous BMAL1 protein (Venus::BMAL1) for quantitative live imaging in physiological settings. The Bmal1Venus mouse model enabled us to visualise and quantify the daily behaviour of this core clock factor in central (SCN) and peripheral clocks, with single-cell resolution that revealed its circadian expression, anti-phasic to negative regulators, nuclear-cytoplasmic mobility and molecular abundance.

Sexual Function and Problematic Use of Smartphones and Social Networking Sites.

BACKGROUND: The use of social networking sites (SNS) sometimes acquires an addictive-like quality, often referred to as problematic use of SNS. This condition overlaps with problematic (addictive-like) use of smartphones, as the latter are commonly used for online social networking in addition to other activities that may gain addictive-like qualities. There is ample evidence that problematic use of smartphones and SNS is associated with poorer mental health, but research on associations with sexual function is scarce. AIM: To examine if sexual difficulties are related to problematic use of SNS and smartphones. METHODS: Data from 4 studies conducted in Portugal between October 2019 and December 2021 (analyzed for the first time) were collapsed, resulting in 946 women and 235 men providing data on sexual function and problematic use of smartphones, and in 536 women and 194 men providing data on sexual function and problematic use of SNS. Female sexual function was assessed with the Female Sexual Function Index and the Female Sexual Distress Scale - Revised (FSDS-R). Male sexual function was assessed by the International Index of Erectile Function. Problematic smartphone use was measured by the Smartphone Addiction Scale - Short Version (SAS-SV). Problematic use of SNS was measured by the Internet Addiction Scale (IAT) specifically adapted to online social networking. OUTCOMES: Participants rated their symptoms of problematic use of smartphones and SNS, as well as their sexual function. RESULTS: In women, problematic use of SNS correlated with lower sexual arousal (r = -0.22), difficulties lubricating (r = -0.13), difficulties having orgasms (r = -0.20), sexual dissatisfaction (r = -0.23), coital pain (r = -0.19), and greater sexual distress (r = 0.33). In men, problematic use of SNS correlated with lower erectile function (r = -0.26), lower desire (r = -0.17), intercourse dissatisfaction (r = -0.20), overall sexual dissatisfaction (r = -0.30), and more difficulties having orgasms (r = -0.20). For both sexes, correlations between sexual function and problematic smartphone use were in the same direction, but were generally weaker and, in most cases, become nonsignificant after controlling for problematic use of SNS. CLINICAL IMPLICATIONS: Addictive-like use of SNS might be a risk factor for sexual difficulties. STRENGTHS & LIMITATIONS: This study is innovative and well-powered to uncover associations between poorer sexual function and addictive-like use of new technologies. The lack of representativeness of the sample warrants caution. CONCLUSIONS: Problematic (addictive-like) use of SNS was associated with male and female sexual difficulties. This corroborates previous research. Fuzeiro V., Martins C., Gonçalves C, et al. Sexual Function and Problematic Use of Smartphones and Social Networking Sites. J Sex Med 2022;19:1303-1308.

In vitro toxicity of particulate matter emissions from residential pellet combustion.

Particulate matter emissions (PM10) from the combustion, in a residential stove, of two commercial brands of certified (ENplus A1) pellets, a non-certified brand and laboratory made pellets of acacia were tested for their ability to induce ecotoxic, cytotoxic, and mutagenic responses in unicellular organisms and a human cell line. Ecotoxicity was evaluated through the Vibrio fischeri bioluminescence inhibition assay. Moreover, cytotoxicity was assessed at two time points (24- and 48-hr) through two complementary techniques in order to evaluate the cellular metabolic activity and membrane integrity of human lung epithelial cells A549. The Ames test using two Salmonella typhimurium strains (TA100 and TA98) was employed to assess the mutagenic potential of the polycyclic aromatic hydrocarbon fraction extracted from the PM10 samples. Results obtained with the bioluminescent bacteria indicated that only particles from the combustion of acacia pellets were toxic. All samples induced impairment on the A549 cells metabolic activity, while no significant release of lactate dehydrogenase was recorded. PM10 emissions from acacia pellets were the most cytotoxic, while samples from both certified pellets evoked significant cytotoxicity at lower doses. Cytotoxicity time-dependency was only observed for PM10 from the combustion of acacia pellets and one of the brands of certified pellets. Mutagenic activity was not detected in both S. typhimurium strains. This study emphasises the role of the raw material for pellet manufacturing on the toxicological profile of PM emissions. Alternative raw materials should be deeply investigated before their use in pelletisation and combustion in residential appliances.

Tissue physiology revolving around the clock: circadian rhythms as exemplified by the intervertebral disc.

Circadian clocks in the brain and peripheral tissues temporally coordinate local physiology to align with the 24 hours rhythmic environment through light/darkness, rest/activity and feeding/fasting cycles. Circadian disruptions (during ageing, shift work and jet-lag) have been proposed as a risk factor for degeneration and disease of tissues, including the musculoskeletal system. The intervertebral disc (IVD) in the spine separates the bony vertebrae and permits movement of the spinal column. IVD degeneration is highly prevalent among the ageing population and is a leading cause of lower back pain. The IVD is known to experience diurnal changes in loading patterns driven by the circadian rhythm in rest/activity cycles. In recent years, emerging evidence indicates the existence of molecular circadian clocks within the IVD, disruption to which accelerates tissue ageing and predispose animals to IVD degeneration. The cell-intrinsic circadian clocks in the IVD control key aspects of physiology and pathophysiology by rhythmically regulating the expression of ~3.5% of the IVD transcriptome, allowing cells to cope with the drastic biomechanical and chemical changes that occur throughout the day. Indeed, epidemiological studies on long-term shift workers have shown an increased incidence of lower back pain. In this review, we summarise recent findings of circadian rhythms in health and disease, with the IVD as an exemplar tissue system. We focus on rhythmic IVD functions and discuss implications of utilising biological timing mechanisms to improve tissue health and mitigate degeneration. These findings may have broader implications in chronic rheumatic conditions, given the recent findings of musculoskeletal circadian clocks.

Localization and Bioreactivity of Cysteine-Rich Secretions in the Marine Gastropod Nucella lapillus.

Marine biodiversity has been yielding promising novel bioproducts from venomous animals. Despite the auspices of conotoxins, which originated the paradigmatic painkiller Prialt, the biotechnological potential of gastropod venoms remains to be explored. Marine bioprospecting is expanding towards temperate species like the dogwhelk Nucella lapillus, which is suspected to secrete immobilizing agents through its salivary glands with a relaxing effect on the musculature of its preferential prey, Mytilus sp. This work focused on detecting, localizing, and testing the bioreactivity of cysteine-rich proteins and peptides, whose presence is a signature of animal venoms and poisons. The highest content of thiols was found in crude protein extracts from the digestive gland, which is associated with digestion, followed by the peribuccal mass, where the salivary glands are located. Conversely, the foot and siphon (which the gastropod uses for feeding) are not the main organs involved in toxin secretion. Ex vivo bioassays with Mytilus gill tissue disclosed the differential bioreactivity of crude protein extracts. Secretions from the digestive gland and peribuccal mass caused the most significant molecular damage, with evidence for the induction of apoptosis. These early findings indicate that salivary glands are a promising target for the extraction and characterization of bioactive cysteine-rich proteinaceous toxins from the species.

Histochemical detection of free thiols in glandular cells and tissues of different marine Polychaeta.

Either through differentiated glands or specialised individual cells, the coating epithelia of soft-bodied marine invertebrates are responsible for the secretion of a broad span of peptidic substances, from protective mucins to biocides. These secretions are characterised by the presence of cysteine-rich proteins and peptides, rendering a distinct histochemical signature of secretory epithelia. Through a histochemical procedure for fluorescence microscopy in paraffin sections, we performed a comparative assessment of the distribution of thiol-rich compounds in multiple epithelia of different species of intertidal Polychaeta, which revealed distinctive patterns of distribution that closely relate to ecology, morphoanatomy and physiology. The presence of free thiols was notorious in mucocytes and enzyme-plus toxin-secreting cells. Consequently, strong signals were recorded in the mucocytes of the parapodia of Nereis splendida, the epidermis and pharynx epithelium of Mysta picta and the venom glands of Glycera alba. The findings show an investment in mucus secretion in foragers such as Nereis and Mysta, especially the latter, which is not a native burrower, as a protective response and as lubricant for locomotion. Additionally, nereidids are believed to secret integumentary toxins for defence. On the other hand, Glycera is an ambush predatorial burrower whose behaviour entirely revolves around the delivery of venom making use of its four jaws. The results showed that the detection of thiol-rich compounds in histological sections can be a tool to identify potential toxin secretion and delivery structures, with important consequences for the bioprospecting of novel bioreactives from marine invertebrates for the purpose of drug discovery.

Identification of inner membrane translocase components of TolC-mediated secretion in the cyanobacterium Synechocystis sp. PCC 6803.

Cyanobacteria were the first organisms ever to perform oxygenic photosynthesis and still significantly contribute to primary production on a global scale. To assure the proper functioning of their primary metabolism and cell homeostasis, cyanobacteria must rely on efficient transport systems to cross their multilayered cell envelope. However, cyanobacterial secretion mechanisms remain largely unknown. Here, we report on the identification of 11 putative inner membrane translocase components of TolC-mediated secretion in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Gene-inactivation of each of the candidate genes followed by a comprehensive phenotypic characterization allowed to link specific protein components to the processes of protein export (as part of the type I secretion system) and drug efflux (part of the resistance-division-nodulation efflux pumps). In addition, mutants in genes sll0141, sll0180 and slr0369 exhibited alterations in pilin glycosylation, but pili structures could still be observed by transmission electron microscopy. By studying the release of outer membrane vesicles (OMVs), an alternative secretion route, on mutants with impaired secretory functions we suggest that the hyper-vesiculating phenotype of the TolC-deficient mutant is related to cell envelope stress management. Altogether, these findings highlight how both classical (TolC-mediated) and nonclassical (OMVs-mediated) secretion systems are crucial for cyanobacterial cell homeostasis.

Development of a method for the detection of polystyrene microplastics in paraffin-embedded histological sections.

The concerns about the presence of microplastics (MPs) in marine ecosystems have widely increased in the past years. This is reflected in a growing number of studies addressing the effects of exposure to these materials in indigenous, farmed and even laboratory marine animals subjected to toxicity-oriented bioassays. There have been, however, many constraints in the detection of MPs in biological tissues, as routine histological techniques tend to degrade these materials, which are especially sensitive to organic solvents. This issue hinders the application of standard histopathological procedures based on convenient paraffin wax-embedding protocols, with consequences for biomonitoring and bioassay procedures. The method described here was developed and validated for the detection of polystyrene microplastics in biological tissue processed for paraffin-based histology. The strategy was developed and tested from whole-soft body sections of marine mussels that internalised the MPs following dedicated bioassays. The protocol is based on the replacement of xylenes with isopropanol for the purpose of intermediate infiltration and deparaffinization. Special modifications for staining, mounting and archiving are needed and are detailed as well. The protocol is shown to be a highly cost- and time-effective procedure compatible with formalin-based fixatives plus standard sectioning and staining, yielding complete preservation of MPs and optimal tissue conditioning. The method also produced excellent results with pre-stained MPs, with fluorochromes included, altogether providing excellent localisation of polystyrene MPs in paraffin-processed biological tissue.

Mechanism-based genotoxicity screening of metal oxide nanoparticles using the ToxTracker panel of reporter cell lines.

BACKGROUND: The rapid expansion of manufacturing and use of nano-sized materials fuels the demand for fast and reliable assays to identify their potential hazardous properties and underlying mechanisms. The ToxTracker assay is a recently developed mechanism-based reporter assay based on mouse embryonic stem (mES) cells that uses GFP-tagged biomarkers for detection of DNA damage, oxidative stress and general cellular stress upon exposure. Here, we evaluated the ability of the ToxTracker assay to identify the hazardous properties and underlying mechanisms of a panel of metal oxide- and silver nanoparticles (NPs) as well as additional non-metallic materials (diesel, carbon nanotubes and quartz). METHODS: The metal oxide- and silver nanoparticles were characterized in terms of agglomeration and ion release in cell medium (using photon cross correlation spectroscopy and inductively coupled plasma with optical emission spectroscopy, respectively) as well as acellular ROS production (DCFH-DA assay). Cellular uptake was investigated by means of transmission electron microscopy. GFP reporter induction and cytotoxicity of the NPs was simultaneously determined using flow cytometry, and genotoxicity was further tested using conventional assays (comet assay, γ-H2AX and RAD51 foci formation). RESULTS: We show that the reporter cells were able to take up nanoparticles and, furthermore, that exposure to CuO, NiO and ZnO nanoparticles as well as to quartz resulted in activation of the oxidative stress reporter, although only at high cytotoxicity for ZnO. NiO NPs activated additionally a p53-associated cellular stress response, indicating additional reactive properties. Conventional assays for genotoxicity assessment confirmed the response observed in the ToxTracker assay. We show for CuO NPs that the induction of oxidative stress is likely the consequence of released Cu ions whereas the effect by NiO was related to the particles per se. The DNA replication stress-induced reporter, which is most strongly associated with carcinogenicity, was not activated by any of the tested nanoparticles. CONCLUSIONS: We conclude that the ToxTracker reporter system can be used as a rapid mechanism-based tool for the identification of hazardous properties of metal oxide NPs. Furthermore, genotoxicity of metal oxide NPs seems to occur mainly via oxidative stress rather than direct DNA binding with subsequent replication stress.

Ecological risk assessment of impacted estuarine areas: integrating histological and biochemical endpoints in wild Senegalese sole.

The analysis of multiple biomarker responses is nowadays recognized as a valuable tool to circumvent potential confounding factors affecting biomonitoring studies and allows a better understanding of the mechanisms underlying exposure to natural mixtures of toxicants. For the purpose of an environmental risk assessment (ERA) in an impacted estuary in SW Europe (the Sado, Portugal), juvenile Solea senegalensis from commercial fishing areas were surveyed for histopathological liver alterations and biochemical biomarkers. Although the findings revealed moderate differences in the patterns of histopathological traits between urban/industrial- and agricultural-influenced areas within the same estuary, no significant distinction was found between the cumulative alterations in animals from the two sites. The overall level of histopathological injury was low and severe traits like neoplasms or pre-neoplastic foci were absent. While metallothionein induction and lipid peroxidation could relate to histopathological condition indices, the activity of anti-oxidant enzymes appeared to be impaired in animals collected off the estuary's heavy-industry belt (the most contaminated site), which may partially explain some degree of hepatic integrity loss. Overall, the results are consistent with low-moderate contamination of the estuary and indicate that oxidative stress is the most important factor accounting for differences between sites. The study highlights the need of integrating multiple biomarkers when multiple environmental stressors are involved and the advantages of surveying toxicity effects in field-collected, foraging, organisms.

The Effectiveness of Nursing Rehabilitation Interventions on Self-Care for Older Adults with Respiratory Disorders: A Systematic Review with Meta-Analysis.

Background: This research work aimed to summarize the rehabilitation nursing interventions published in the scientific literature that most contribute to effective adherence to self-care in older adults with respiratory diseases. Methods: A systematic literature review with meta-analysis was conducted by searching the EBSCOhost platform (CINAHL Complete, MEDLINE Complete, Cochrane, and MedicLatina) using the PRISMA methodology. Five articles were selected for final analysis. Meta-analysis was carried out using Comprehensive Meta-Analysis (CMA) software, and the results were presented in a forest plot. Results: Thirty-one self-promoting rehabilitation nursing interventions were identified, with the most effective being those related to the assessment of progress in physical capacity/activity tolerance (functional status category/domain) and the assessment of the increase in health-related quality of life (health-related quality of life category/domain). Conclusions: Rehabilitation nursing interventions such as self-management programs led by nurses, community-based and home-based rehabilitation programs, and inspiratory muscle training can effectively reduce and enable the effective control of symptoms associated with respiratory disorders, boosting older adults' empowerment to engage in self-care.

Toxicological and Mutagenic Effects of Particulate Matter from Domestic Activities.

People spend most of their time indoors, particularly in their houses where daily activities are carried out, enhancing particulate matter (PM) emissions with consequent adverse health impacts. This study intended to appraise the toxicological and mutagenic responses of particulate matter with a diameter less than 10 µm (PM10) released from cooking and ironing activities under different conditions. The cytotoxicity of the PM10 total organic extracts was tested in A549 cells using the WST-8 and the lactate dehydrogenase (LDH) assays, while the interference in cell cycle dynamics and reactive oxygen species (ROS) production was analysed by flow cytometry. The S. typhimurium TA98 and TA100 Ames tester strains with and without metabolic activation were employed to determine the mutagenic potential of the PM10-bound polycyclic aromatic hydrocarbons (PAHs). PM10 organic extracts decreased the metabolic activity of A549 cells; however, no effects in the LDH release were observed. An increase in ROS levels was registered only for cells treated with PM10 at IC20 from steam ironing, in low ventilation conditions, while cell cycle dynamics was only affected by exposure to PM10 at IC20 from frying horse mackerel and grilling boneless pork strips. No mutagenic effects were observed for all the PM10-bound PAHs samples.

Exhaust emissions of gaseous and particle size-segregated water-soluble organic compounds from diesel-biodiesel blends.

This study assessed the emissions of gaseous pollutants and particle size distributed water-soluble organics (WSO) from a diesel vehicle fuelled with ultralow sulphur diesel (B0) and 10 (B10), 20 (B20), and 30% (B30) biodiesel blends in a chassis dynamometer tested under transient mode. Particulate emission sampling was carried out in an ultraviolet (UV) test chamber using a 10-stage impactor. Samples were grouped into three size fractions and analysed by gas chromatography-mass spectrometry. Increasing the biofuel ratio up to 30% in the fuel reduced WSO emissions by 20.9% in comparison with conventional diesel. Organic acids accounted for 82-89% of WSO in all tested fuels. Dicarboxylic acids were the most abundant compound class, followed by hydroxy, aromatic, and linear alkanoic acids. Correlations between compounds demonstrated that adding biodiesel to diesel fuel reduces the emissions of nitrogen oxides (NOx), benzene, toluene, ethylbenzene and xylenes (BTEX), methane (CH4), total and nonmethane hydrocarbons (THC and NMHC), and dicarboxylic and hydroxy acids, but increases emissions of carbon dioxide (CO2) and alkanoic and aromatic acids. Emissions of dicarboxylic and hydroxy acids were strongly correlated with the biodiesel content. WSO emissions of coarse and fine (1.0-10 µm) particles decreased with the increasing biofuel content in fuel blend. The total share of ultrafine (0.18-1.0 µm) and nanoparticles (< 0.18 µm) increased in WSOs emissions from B20 and B30 blends, when compared with petrodiesel. The biodiesel content also affected the chemical profile of WSO size fractions.

Mechanical loading and hyperosmolarity as a daily resetting cue for skeletal circadian clocks.

Daily rhythms in mammalian behaviour and physiology are generated by a multi-oscillator circadian system entrained through environmental cues (e.g. light and feeding). The presence of tissue niche-dependent physiological time cues has been proposed, allowing tissues the ability of circadian phase adjustment based on local signals. However, to date, such stimuli have remained elusive. Here we show that daily patterns of mechanical loading and associated osmotic challenge within physiological ranges reset circadian clock phase and amplitude in cartilage and intervertebral disc tissues in vivo and in tissue explant cultures. Hyperosmolarity (but not hypo-osmolarity) resets clocks in young and ageing skeletal tissues and induce genome-wide expression of rhythmic genes in cells. Mechanistically, RNAseq and biochemical analysis revealed the PLD2-mTORC2-AKT-GSK3ß axis as a convergent pathway for both in vivo loading and hyperosmolarity-induced clock changes. These results reveal diurnal patterns of mechanical loading and consequent daily oscillations in osmolarity as a bona fide tissue niche-specific time cue to maintain skeletal circadian rhythms in sync.

Subtype-specific circadian clock dysregulation modulates breast cancer biology, invasiveness, and prognosis.

Studies in shift workers and model organisms link circadian disruption to breast cancer. However, molecular rhythms in non-cancerous and cancerous human breast tissues are largely unknown. We reconstructed rhythms informatically, integrating locally collected, time-stamped biopsies with public datasets. For non-cancerous tissue, the inferred order of core-circadian genes matches established physiology. Inflammatory, epithelial-mesenchymal transition (EMT), and estrogen responsiveness pathways show circadian modulation. Among tumors, clock correlation analysis demonstrates subtype-specific changes in circadian organization. Luminal A organoids and informatic ordering of Luminal A samples exhibit continued, albeit disrupted rhythms. However, CYCLOPS magnitude, a measure of global rhythm strength, varied widely among Luminal A samples. Cycling of EMT pathway genes was markedly increased in high-magnitude Luminal A tumors. Patients with high-magnitude tumors had reduced 5-year survival. Correspondingly, 3D Luminal A cultures show reduced invasion following molecular clock disruption. This study links subtype-specific circadian disruption in breast cancer to EMT, metastatic potential, and prognosis.

In vitro toxicity of indoor and outdoor PM10 from residential wood combustion.

Particulate matter with aerodynamic diameter < 10 µm (PM10) was collected, indoors and outdoors, when wood burning appliances (open fireplace and woodstove) were in operation. The PM10 ecotoxicity was assessed with the Vibrio fischeri bioluminescence inhibition assay, while the cytotoxicity was evaluated by the WST-8 and lactate dehydrogenase (LDH) release assays using A549 cells. Extracts of PM10-bound polycyclic aromatic hydrocarbons (PAH) were tested for their mutagenicity through the TA98 and TA100 Ames test. The bioluminescent inhibition assay revealed that indoor particles released from the fireplace were the most toxic. Indoors, the reduction in A549 cell metabolic activity was over two times higher for the fireplace in comparison with the woodstove (32 ± 3.2% and 72 ± 7.6% at the highest dose, respectively). Indoor particles from the fireplace were found to induce greater cytotoxicity than the corresponding outdoor samples. Combined WST-8 and LDH results suggest that PM10 exposure induce apoptotic cell death pathway in which the cell membrane integrity is maintained. Indoor and outdoor samples lacked direct and indirect mutagenic activity in any of the tester strains. For indoor-generated PM10, organic carbon and PAH were significantly correlated with cell viability and bioluminescence reduction, suggesting a role of organic compounds in toxicity.

Organic speciation of atmospheric particles in Alvão Natural Park (Portugal).

PM(10) continental rural background aerosols were collected during a summer field campaign (August-September 2006) at Lamas de Olo in the upper zone of the Alvão Natural Park, a mountain region of northern Portugal. In addition to the determination of the carbonaceous content by a thermal-optical method, the organic speciation of aerosols was performed by gas chromatography-mass spectrometry in an effort to evaluate photo-oxidation products of biogenic volatile organic compounds and other markers for source characterization. The detailed analysis revealed relatively high concentrations of polyols and short-chain dicarboxylic, tricarboxylic, hydroxycarboxylic, and oxocarboxylic acids, many of which are thought to be indicators of secondary aerosol formation, accounting for about 70% of global chromatographically resolved mass. Major photo-oxidation products of alpha- and beta-pinene have been detected. The tracers for the photo-oxidation of isoprene comprise two diastereoisomeric 2-methyltetrols, C(5)-alkene triols, and 2-methylglyceric acid, which have only recently been elucidated. In addition, the occurrence of levoglucosan and other biomass combustion tracers indicates that the site was affected by wildfires. This source contributed to more than 80% of the organic carbon mass during a period of strong forest fire influence.

Health professionals' migration: the Portuguese case.

Migration of health professionals has been an important issue on the agenda of governments in recent years. The European Union directive on the recognition of professional qualifications coupled with labour shortages in the health sector has led to a growing mobility of physicians from both European countries and non-European Economic Area (EEA) countries. This study takes a deeper look at these migration phenomena in the Portuguese case. A significantly convergent dual pattern of migration is shown to emerge, in which the growth of intra-European migration has broadly continued to coexist with the maintenance of traditional overseas immigration channels.