RESUMO
OBJECTIVE: This case report discusses a successful emergency Lichtenberger lateralisation procedure after immediate bilateral laryngeal immobility, occurring after total thyroidectomy. METHODS: A 63-year-old female with right-sided vocal fold paralysis due to compression by a multinodular thyroid goitre underwent total thyroidectomy, which resulted in immediate post-operative bilateral vocal fold immobility. The patient had acute-onset post-operative dyspnoea, was promptly re-intubated, and an emergency lateralisation Lichtenberger suture was placed over the right vocal fold and fixated on the outer surface of the neck. RESULTS: After two weeks, her right vocal fold recovered first, with the suture still in place. At four weeks, both vocal folds regained function and the suture was extracted. CONCLUSION: The take-away message is that an emergency lateralisation suture may be a viable option in maintaining airway patency, while allowing for normal deglutition, in patients who would otherwise be candidates for prolonged intubation, posterior cordotomy, medial arytenoidectomy or tracheostomy.
Assuntos
Tireoidectomia , Paralisia das Pregas Vocais , Humanos , Feminino , Pessoa de Meia-Idade , Tireoidectomia/efeitos adversos , Paralisia das Pregas Vocais/etiologia , Paralisia das Pregas Vocais/cirurgia , Prega Vocal , Traqueostomia/efeitos adversos , Dispneia/etiologia , Dispneia/cirurgiaRESUMO
The antigenic makeup of tumour cells can have a profound effect on the progression of cancer and success of immunotherapies. Therefore, one strategy to improve the efficacy of cancer treatments is to augment the antigens displayed by tumours. The present study explores how the recognition of tumour cells may be altered by non-cytotoxic concentrations of gemcitabine (GEM). Testing a panel of chemotherapeutics in human cancer cell lines in vitro, it was found that GEM increased surface expression of HLA-A,B,C and that underlying this were specific increases in ß-2-microglobulin and immunoproteasome subunit proteins. Furthermore, the peptide antigen repertoire displayed on HLA class I was altered, revealing a number of novel antigens, many of which that were derived from proteins involved in the DNA-damage response. Changes in the nature of the peptide antigens eluted from HLA-A,B,C after GEM treatment consisted of amino acid anchor-residue modifications and changes in peptide length which rendered peptides likely to favour alternative HLA-alleles and increased their predicted immunogenicity. Signalling through the MAPK/ERK and NFκB/RelB pathways was associated with these changes. These data may explain observations made in previous in vivo studies, advise as to which antigens should be used in future vaccination protocols and reinforce the idea that chemotherapy and immunotherapy could be used in combination.
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Caries is the most common disease in the world. Great efforts have been undertaken for prevention and to identify a regenerative treatment solution for dental caries. Self-assembling ß-sheet forming peptides have previously shown to form 3-dimensional fiber networks supporting tissue regeneration. In particular, the self-assembling peptide P11-4 has shown potential in the treatment and prevention of dental caries. It has previously been shown that application of monomeric P11-4 solution to early carious lesions can increase net mineral gain by forming de novo hydroxyapatite crystals. The hypothesis for the mode of action was that monomeric self-assembling peptide P11-4 diffuses into the subsurface lesion body and assembles therein into higher order fibrils, facilitating mineralization of the subsurface volume by mimicking the natural biomineralization of the tooth enamel, and it remains within the lesion body as a scaffold built-in by the newly formed hydroxyapatite. The aim of the present study was to investigate the mechanism of action of the self-assembling peptide P11-4 supporting mineralization of carious enamel. By various analytical methods, it could be shown that the self-assembling peptide P11-4 diffuses into the subsurface lesion, assembles into higher formed aggregates throughout the whole volume of the lesion, and supports nucleation of de novo hydroxyapatite nanocrystals and consequently results in increased mineral density within the subsurface carious lesion. The results showed that the application of self-assembling peptide P11-4 can facilitate the subsurface regeneration of the enamel lesion by supporting de novo mineralization in a similar mode of action as has been shown for the natural formation of dental enamel.
Assuntos
Materiais Biomiméticos/química , Cárie Dentária/terapia , Esmalte Dentário/efeitos dos fármacos , Oligopeptídeos/química , Remineralização Dentária/métodos , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Propriedades de Superfície , Microtomografia por Raio-XRESUMO
Recent studies suggest that multiple myeloma is an immunogenic disease, which might be effectively targeted by antigen-specific T-cell immunotherapy. As standard of care in myeloma includes proteasome inhibitor therapy, it is of great importance to characterize the effects of this treatment on HLA-restricted antigen presentation and implement only robustly presented targets for immunotherapeutic intervention. Here, we present a study that longitudinally and semi-quantitatively maps the effects of the proteasome inhibitor carfilzomib on HLA-restricted antigen presentation. The relative presentation levels of 4780 different HLA ligands were quantified in an in vitro model employing carfilzomib treatment of MM.1S and U266 myeloma cells, which revealed significant modulation of a substantial fraction of the HLA-presented peptidome. Strikingly, we detected selective down-modulation of HLA ligands with aromatic C-terminal anchor amino acids. This particularly manifested as a marked reduction in the presentation of HLA ligands through the HLA allotypes A*23:01 and A*24:02 on MM.1S cells. These findings implicate that carfilzomib mediates a direct, peptide motif-specific inhibitory effect on HLA ligand processing and presentation. As a substantial proportion of HLA allotypes present peptides with aromatic C-termini, our results may have broad implications for the implementation of antigen-specific treatment approaches in patients undergoing carfilzomib treatment.
Assuntos
Apresentação de Antígeno/efeitos dos fármacos , Apresentação de Antígeno/imunologia , Epitopos/imunologia , Antígenos HLA/imunologia , Mieloma Múltiplo/imunologia , Oligopeptídeos/farmacologia , Peptídeos/imunologia , Biomarcadores , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Epitopos/química , Epitopos/metabolismo , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/metabolismo , Antígenos HLA/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Imunofenotipagem , Ligantes , Espectrometria de Massas , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Mieloma Múltiplo/terapia , Peptídeos/química , Peptídeos/metabolismo , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/uso terapêuticoRESUMO
Oxidative potential (OP) is related to the organic phase, specifically to its oxygenated organic fraction (OOA). Furthermore, the oxygen content of fuel molecules has significant influence on particulate OP. Thus, this study aimed to explore the actual dependency of the OOA and ROS to the oxygen content of the fuel. In order to reach the goal, different biodiesels blends, with various ranges of oxygen content; have been employed. The compact time of flight aerosol mass spectrometer (c-ToF AMS) enabled better identification of OOA. ROS monitored by using two assays: DTT and BPEA-nit. Despite emitting lower mass, both assays agreed that oxygen content of a biodiesel is directly correlated with its OOA, and highly related to its OP. Hence, the more oxygen included in the considered biodiesels, the higher the OP of PM emissions. This highlights the importance of taking oxygen content into account while assessing emissions from new fuel types, which is relevant from a health effects standpoint.
Assuntos
Poluentes Atmosféricos/análise , Biocombustíveis/análise , Oxigênio/análise , Material Particulado/análise , Monitoramento Ambiental , Oxirredução , Emissões de Veículos/análiseRESUMO
Arthropod hemocyanins (Hcs) are a family of large extracellular oxygen-transporting proteins with high molecular mass and hexameric or multi-hexameric molecular assembly. This study reports for the first time the isolation and characterization of the structure of an arthropod hemocyanin from crab Eriphia verrucosa (EvH) living in the Black Sea. Its oligomeric quaternary structure is based on different arrangements of a basic 6 × 75 kDa hexameric unit, and four of them (EvH1, EvH2, EvH3, and EvH4) were identified using ion-exchange chromatography. Subunit 3 (EvH3) shows high similarity scores (75.0, 87.5, 91.7, and 75.0 %, respectively) by comparison of the N-terminal sequence of subunit 1 from Cancer pagurus of the North Sea (Cp1), subunits 3 and 6 of Cancer magister (Cm3 and Cm6), and subunit 2 of Carcinus aestuarii (CaSS2), respectively. Moreover, a partial cDNA sequence (1309 bp) of E. verrucosa hemocyanin encoding a protein of 435 amino acids was isolated. The deduced amino acid sequence shows a high degree of similarity with subunits 3, 4, 5, and 6 of C. magister (81-84 %). Most of the hemocyanins are glycosylated, and three putative O-linkage sites were identified in the partial amino acid sequence of EvH at positions 444-446, 478-480, and 547-549, respectively. The higher stability of native Hc in comparison to its subunit EvH4 as determined by circular dichroism (CD) could be explained with the formation of a stabilizing quaternary structure.
Assuntos
Braquiúros/metabolismo , Hemocianinas/química , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação/genética , Braquiúros/genética , Cromatografia Líquida de Alta Pressão , Cromatografia por Troca Iônica , Clonagem Molecular , Feminino , Hemocianinas/genética , Hemocianinas/isolamento & purificação , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Estrutura Quaternária de Proteína , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Microalgae are considered to be one of the most viable biodiesel feedstocks for the future due to their potential for providing economical, sustainable and cleaner alternatives to petroleum diesel. This study investigated the particle emissions from a commercially cultured microalgae and higher plant biodiesels at different blending ratios. With a high amount of long carbon chain lengths fatty acid methyl esters (C20 to C22), the microalgal biodiesel used had a vastly different average carbon chain length and level of unsaturation to conventional biodiesel, which significantly influenced particle emissions. Smaller blend percentages showed a larger reduction in particle emission than blend percentages of over 20%. This was due to the formation of a significant nucleation mode for the higher blends. In addition measurements of reactive oxygen species (ROS), showed that the oxidative potential of particles emitted from the microalgal biodiesel combustion were lower than that of regular diesel. Biodiesel oxygen content was less effective in suppressing particle emissions for biodiesels containing a high amount of polyunsaturated C20-C22 fatty acid methyl esters and generated significantly increased nucleation mode particle emissions. The observed increase in nucleation mode particle emission is postulated to be caused by very low volatility, high boiling point and high density, viscosity and surface tension of the microalgal biodiesel tested here. Therefore, in order to achieve similar PM (particulate matter) emission benefits for microalgal biodiesel likewise to conventional biodiesel, fatty acid methyl esters (FAMEs) with high amounts of polyunsaturated long-chain fatty acids (≥C20) may not be desirable in microalgal biodiesel composition.
Assuntos
Poluentes Atmosféricos/análise , Biocombustíveis , Microalgas , Material Particulado/análise , Oxirredução , Espécies Reativas de OxigênioRESUMO
Natural killer (NK) cells are cytotoxic lymphocytes that substantially contribute to the therapeutic benefit of antitumor antibodies like Rituximab, a crucial component in the treatment of B-cell malignancies. In chronic lymphocytic leukemia (CLL), the ability of NK cells to lyse the malignant cells and to mediate antibody-dependent cellular cytotoxicity upon Fc receptor stimulation is compromised, but the underlying mechanisms are largely unclear. We report here that NK-cells activation-dependently produce the tumor necrosis factor family member 'B-cell activating factor' (BAFF) in soluble form with no detectable surface expression, also in response to Fc receptor triggering by therapeutic CD20-antibodies. BAFF in turn enhanced the metabolic activity of primary CLL cells and impaired direct and Rituximab-induced lysis of CLL cells without affecting NK reactivity per se. The neutralizing BAFF antibody Belimumab, which is approved for treatment of systemic lupus erythematosus, prevented the effects of BAFF on the metabolism of CLL cells and restored their susceptibility to direct and Rituximab-induced NK-cell killing in allogeneic and autologous experimental systems. Our findings unravel the involvement of BAFF in the resistance of CLL cells to NK-cell antitumor immunity and Rituximab treatment and point to a benefit of combinatory approaches employing BAFF-neutralizing drugs in B-cell malignancies.
Assuntos
Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Murinos/farmacologia , Citotoxicidade Celular Dependente de Anticorpos/efeitos dos fármacos , Fator Ativador de Células B/imunologia , Células Matadoras Naturais/imunologia , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/imunologia , Antineoplásicos/farmacologia , Apoptose , Fator Ativador de Células B/antagonistas & inibidores , Fator Ativador de Células B/genética , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Western Blotting , Proliferação de Células , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Humanos , Técnicas Imunoenzimáticas , Imunossupressores/farmacologia , Células Matadoras Naturais/efeitos dos fármacos , Fragmentos de Peptídeos/análise , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rituximab , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Células Tumorais CultivadasRESUMO
Identification of physiologically relevant peptide vaccine targets calls for the direct analysis of the entirety of naturally presented human leukocyte antigen (HLA) ligands, termed the HLA ligandome. In this study, we implemented this direct approach using immunoprecipitation and mass spectrometry to define acute myeloid leukemia (AML)-associated peptide vaccine targets. Mapping the HLA class I ligandomes of 15 AML patients and 35 healthy controls, more than 25 000 different naturally presented HLA ligands were identified. Target prioritization based on AML exclusivity and high presentation frequency in the AML cohort identified a panel of 132 LiTAAs (ligandome-derived tumor-associated antigens), and 341 corresponding HLA ligands (LiTAPs (ligandome-derived tumor-associated peptides)) represented subset independently in >20% of AML patients. Functional characterization of LiTAPs by interferon-γ ELISPOT (Enzyme-Linked ImmunoSpot) and intracellular cytokine staining confirmed AML-specific CD8(+) T-cell recognition. Of note, our platform identified HLA ligands representing several established AML-associated antigens (e.g. NPM1, MAGED1, PRTN3, MPO, WT1), but found 80% of them to be also represented in healthy control samples. Mapping of HLA class II ligandomes provided additional CD4(+) T-cell epitopes and potentially synergistic embedded HLA ligands, allowing for complementation of a multipeptide vaccine for the immunotherapy of AML.
Assuntos
Vacinas Anticâncer/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe I/genética , Imunoterapia Ativa/métodos , Leucemia Mieloide Aguda/terapia , Proteínas de Neoplasias/imunologia , Peptídeos/imunologia , Sequência de Aminoácidos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Vacinas Anticâncer/administração & dosagem , Vacinas Anticâncer/genética , Estudos de Casos e Controles , Epitopos de Linfócito T/química , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Expressão Gênica , Antígenos de Histocompatibilidade Classe I/química , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/química , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Imunoprecipitação , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/imunologia , Leucemia Mieloide Aguda/patologia , Ligantes , Espectrometria de Massas , Dados de Sequência Molecular , Proteínas de Neoplasias/genética , Nucleofosmina , Mapeamento de Peptídeos , Peptídeos/química , Peptídeos/genéticaRESUMO
We have studied the effect of chemical composition of biodiesel fuel on the physical (volatility) and chemical (reactive oxygenated species concentration) properties of nano particles emitted from a modern common-rail diesel engine. Particle emissions from the combustion of four biodiesels with controlled chemical compositions and different varying unsaturation degrees and carbon-chain lengths, together with a commercial diesel, were tested and compared in terms of volatility of particles and the amount of reactive oxygenated species carried by particles. Different blends of biodiesel and petro diesel were tested at several engine loads and speeds. We have observed that more saturated fuels with shorter carbon chain lengths result in lower particle mass but produce particles that are more volatile and also have higher levels of Reactive Oxygen Species. This highlights the importance of taking into account metrics that are relevant from the health effects point of view when assessing emissions from new fuel types.
Assuntos
Biocombustíveis/análise , Material Particulado/análise , Emissões de Veículos/análise , Estrutura Molecular , Oxirredução , Material Particulado/química , VolatilizaçãoRESUMO
T cells have been proven to be therapeutically effective in patients with relapsed leukemias, although target antigens on leukemic cells as well as T-cell receptors (TCRs), potentially recognizing those antigens, are mostly unknown. We have applied an immunopeptidomic approach and isolated human leukocyte antigen (HLA) ligands from primary leukemia cells. We identified a number of ligands derived from different genes that are restrictedly expressed in the hematopoietic system. We exemplarily selected myeloperoxidase (MPO) as a potential target and isolated a high-avidity TCR with specificity for a HLA-B*07:02-(HLA-B7)-restricted epitope of MPO in the single HLA-mismatched setting. T cells transgenic for this TCR demonstrated high peptide and antigen specificity as well as leukemia reactivity in vitro and in vivo. In contrast, no significant on- and off-target toxicity could be observed. In conclusion, we here demonstrate, exemplarily for MPO, that leukemia-derived HLA ligands can be selected for specific effector tool development to redirect T cells to be used for graft manipulation or adoptive T-cell therapies in diverse transplant settings. This approach can be extended to other HLA ligands and HLA molecules in order to provide better treatment options for this life-threatening disease.
Assuntos
Antígenos HLA/imunologia , Leucemia Mieloide/genética , Leucemia Mieloide/imunologia , Peptídeos/imunologia , Peroxidase/imunologia , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T/imunologia , Linfócitos T/metabolismo , Animais , Apresentação de Antígeno/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Modelos Animais de Doenças , Mapeamento de Epitopos , Epitopos de Linfócito T/química , Epitopos de Linfócito T/imunologia , Antígenos HLA/metabolismo , Antígeno HLA-B7/imunologia , Antígeno HLA-B7/metabolismo , Xenoenxertos , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Leucemia Mieloide/metabolismo , Leucemia Mieloide/mortalidade , Ligantes , Camundongos , Peptídeos/metabolismo , Peroxidase/química , Peroxidase/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Especificidade do Receptor de Antígeno de Linfócitos T/imunologia , Transdução GenéticaRESUMO
Generally, the magnitude of pollutant emissions from diesel engines running on biodiesel fuel is ultimately coupled to the structure of the fuel's constituent molecules. Previous studies demonstrated the relationship between the organic fraction of particulate matter (PM) and its oxidative potential. Herein, emissions from a diesel engine running on different biofuels were analyzed in more detail to explore the role that different organic fractions play in the measured oxidative potential. In this work, a more detailed chemical analysis of biofuel PM was undertaken using a compact time of flight aerosol mass spectrometer (c-ToF AMS). This enabled a better identification of the different organic fractions that contribute to the overall measured oxidative potentials. The concentration of reactive oxygen species (ROS) was measured using a profluorescent nitroxide molecular probe 9-(1,1,3,3-tetramethylisoindolin-2-yloxyl-5-ethynyl)-10-(phenylethynyl)anthracene (BPEAnit). Therefore, the oxidative potential of the PM, measured through the ROS content, although proportional to the total organic content in certain cases, shows a much higher correlation with the oxygenated organic fraction as measured by the c-ToF AMS. This highlights the importance of knowing the surface chemistry of particles for assessing their health impacts. It also sheds light onto new aspects of particulate emissions that should be taken into account when establishing relevant metrics for assessing health implications of replacing diesel with alternative fuels.
Assuntos
Aerossóis/química , Gasolina , Compostos Orgânicos/química , Oxigênio/química , Material Particulado , OxirreduçãoRESUMO
We measured the densities of 1-alkyl-3-methylimidazolium (C(n)mim, n = 2,4,6) tris(pentafluoroethyl)trifluorophosphate ionic liquids (eFAP) as a function of temperature and pressure and their viscosities as a function of temperature. These ionic liquids are less viscous than those based in the same cations but with other anions such as bis(trifluoromethylsulfonyl)imide. The ionic liquids studied are only partially miscible with water, their solubility increasing with the size of the alkyl side-chain of the cation and with temperature (from x(H(2)O) = 0.20 ± 0.03 for [C(4)mim][eFAP] at 303.10 K to x(H(2)O) = 0.49 ± 0.07 for [C(6)mim][eFAP] at 315.10 K). The solubility of carbon dioxide, nitrous oxide, ethane, and nitrogen in the three ionic liquids was measured as a function of temperature and at pressures close to atmospheric. Carbon dioxide and nitrous oxide are the more soluble gases with mole fraction solubilities of the order of 3 × 10(-2) at 303 K. The solubility of these gases does not increase linearly with the size of the alkyl-side chain of the cation. The solubilities of ethane and nitrogen are much lower than those of carbon dioxide and nitrous oxide (mole fractions 60% and 90% lower, respectively). The higher solubility of CO(2) and N(2)O can be explained by more favorable interactions between the solutes and the polar region of the ionic liquids as shown by the enthalpies of solvation determined experimentally and by the calculation of the site-site solute-solvent radial distribution functions using molecular simulation.
RESUMO
Adoptive immunotherapy with donor lymphocyte infusion (DLI) after allogeneic stem cell transplantation (alloSCT) may not only mediate Graft-versus-Leukemia (GvL) reactivity, but also induce Graft-versus-Host Disease (GvHD). As HLA-class II molecules are predominantly expressed on hematopoietic cells, CD4+ T cells may selectively mediate GvL reactivity without GvHD. Here, we assessed the capacity of human CD4+ T cells to act as sole mediators of GvL reactivity in a NOD/scid mouse model for human acute lymphoblastic leukemia and chronic myeloid leukemia in lymphoid blast crisis. Highly purified CD4+ DLI eradicated the leukemic cells. The anti-tumor immunity was mediated by a polyclonal CD4+ T cell response comprising cytokine-producing T-helper and cytolytic T-effector cells directed against the mismatched HLA-class II molecules of the patients. Furthermore, primary leukemic cells acquired an antigen-presenting cell (APC) phenotype in vivo after DLI, as well as in vitro after co-culture with leukemia-specific CD4+ T cells. In conclusion, our results show that CD4+ T cells can be strong mediators of anti-tumor immunity, and provide evidence that cross-talk between CD4+ T cells and leukemic cells is the basis for induction of leukemic cells with an APC phenotype. These data emphasize the clinical relevance of CD4+ T cell based immunotherapy as treatment modality for hematological malignancies after alloSCT.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/imunologia , Animais , Humanos , Imunoterapia Adotiva , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologiaRESUMO
This study undertook a physicochemical characterization of particle emissions from a single compression ignition engine operated at one test mode with 3 biodiesel fuels made from 3 different feedstocks (i.e., soy, tallow, and canola) at 4 different blend percentages (20%, 40%, 60%, and 80%) to gain insights into their particle-related health effects. Particle physical properties were inferred by measuring particle number size distributions both with and without heating within a thermodenuder (TD) and also by measuring particulate matter (PM) emission factors with an aerodynamic diameter less than 10 µm (PM(10)). The chemical properties of particulates were investigated by measuring particle and vapor phase Polycyclic Aromatic Hydrocarbons (PAHs) and also Reactive Oxygen Species (ROS) concentrations. The particle number size distributions showed strong dependency on feedstock and blend percentage with some fuel types showing increased particle number emissions, while others showed particle number reductions. In addition, the median particle diameter decreased as the blend percentage was increased. Particle and vapor phase PAHs were generally reduced with biodiesel, with the results being relatively independent of the blend percentage. The ROS concentrations increased monotonically with biodiesel blend percentage but did not exhibit strong feedstock variability. Furthermore, the ROS concentrations correlated quite well with the organic volume percentage of particles - a quantity which increased with increasing blend percentage. At higher blend percentages, the particle surface area was significantly reduced, but the particles were internally mixed with a greater organic volume percentage (containing ROS) which has implications for using surface area as a regulatory metric for diesel particulate matter (DPM) emissions.
Assuntos
Poluentes Atmosféricos/química , Biocombustíveis/análise , Material Particulado/química , Poluentes Atmosféricos/análise , Conservação de Recursos Energéticos , Tamanho da Partícula , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Espécies Reativas de Oxigênio/análise , Medição de Risco , Emissões de VeículosRESUMO
BACKGROUND: Congenital unilateral hydrocephalus is an uncommon entity occurring almost exclusively in children. Atresia, stenosis, membranous occlusion and even functional obstruction of the foramen of Monro have been described to be the main cause of this type of hydrocephalus. There are two options available in the surgical management of unilateral hydrocephalus: one is the placement of shunt CSF diversion from the dilated ventricle and the other is fenestration of the occluded foramen of Monro or septum pellucidum by endoscopy or by stereotactic method. Migration of the ventriculoperitoneal (VP) shunt in or out of ventricles is not so uncommon, but the relocation of the ventricular tip of a catheter from the ventricle into the quadrigeminal cisterns and superior vermis in association with ventriculostomy is extremely rare. Spontaneous ventriculostomy is a rare event and results from spontaneous rupture of a ventricle into the subarachnoid space. CASE DESCRIPTION: A 5½-month-old baby with a right-sided congenital unilateral hydrocephalus underwent a VP shunt andhad experienced an uneventful outcome. Four years later on an MR imaging examination, the tip of the ventricular catheter passing through the medial wall of the ventricle and the quadrigeminal cistern was found to be situated in the superior vermis. During the follow-up period, there were no neurological difficulties. The cognitive and motor skill development corresponded well with the child's age. It transpired that the hydrocephalic ventricle reduced its size dramatically to normal. CONCLUSION: We have described the extremely rare site of the relocation of the ventricular catheter after the treatment of the congenital unilateral hydrocephalus by VP shunting. Spontaneous ventriculostomy as a rare phenomenon may be the explanation of the relocation of the ventricular catheter.