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1.
Artigo em Inglês | MEDLINE | ID: mdl-38877185

RESUMO

BACKGROUND: The purpose of this research was to examine the probability of ipsilateral breast cancer recurrence in individuals whose RT was delayed after the first chemotherapy and surgery. PURPOSE: To analyze the effect of delaying RT for breast cancer patients (by more than 6 weeks after treatment). METHODOLOGY: A retrospective analysis comprised 136 female breast cancer patients treated at the Baghdad Centre for Radiation Oncology and Nuclear Medicine from 2021 to May 2022. External beam radiation was started more than 6 weeks after chemotherapy was finished for all patients who also had surgery. Clinical examination and ultrasound were part of the follow-up process. RESULTS: Patients' ages varied from 28 to 71, and the majority (83%) had a mastectomy. The majority of cases (95.5%) were diagnosed as invasive ductal carcinoma on histopathology, with 49.6% being at stage 2 and 42.6% being at stage 3. Seventy-six percent of patients tested positive for hormones. Although 10 patients (7.35%) acquired distant metastases within 5 years, only 2 (1.47%) had local recurrence because of the delay in RT. Specifically, 91.1% had complete local control with no evidence of disease spread. CONCLUSION: Delaying RT by more than 6 weeks in patients with breast cancer did not substantially affect local control, according to the results of a new research, the first of its type in Iraq.

2.
Sci Rep ; 11(1): 9363, 2021 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-33931662

RESUMO

The presence of magnetic nanoparticles (MNPs) in the human brain was attributed until recently to endogenous formation; associated with a putative navigational sense, or with pathological mishandling of brain iron within senile plaques. Conversely, an exogenous, high-temperature source of brain MNPs has been newly identified, based on their variable sizes/concentrations, rounded shapes/surface crystallites, and co-association with non-physiological metals (e.g., platinum, cobalt). Here, we examined the concentration and regional distribution of brain magnetite/maghemite, by magnetic remanence measurements of 147 samples of fresh/frozen tissues, from Alzheimer's disease (AD) and pathologically-unremarkable brains (80-98 years at death) from the Manchester Brain Bank (MBB), UK. The magnetite/maghemite concentrations varied between individual cases, and different brain regions, with no significant difference between the AD and non-AD cases. Similarly, all the elderly MBB brains contain varying concentrations of non-physiological metals (e.g. lead, cerium), suggesting universal incursion of environmentally-sourced particles, likely across the geriatric blood-brain barrier (BBB). Cerebellar Manchester samples contained significantly lower (~ 9×) ferrimagnetic content compared with those from a young (29 years ave.), neurologically-damaged Mexico City cohort. Investigation of younger, variably-exposed cohorts, prior to loss of BBB integrity, seems essential to understand early brain impacts of exposure to exogenous magnetite/maghemite and other metal-rich pollution particles.


Assuntos
Poluentes Atmosféricos/análise , Doença de Alzheimer/epidemiologia , Encéfalo/patologia , Nanopartículas de Magnetita/análise , Metais/análise , Idoso de 80 Anos ou mais , Poluentes Atmosféricos/efeitos adversos , Doença de Alzheimer/etiologia , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Estudos de Casos e Controles , Feminino , Humanos , Nanopartículas de Magnetita/efeitos adversos , Masculino , Metais/efeitos adversos , Reino Unido/epidemiologia
3.
Chemosphere ; 270: 129388, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33423005

RESUMO

Auriferous sulphide ores often incorporate micro-fine (or invisible) gold and silver particles in a manner making their extraction difficult. Nobel metals are lost in the tailings due to the refractory nature of these ores. Bioleaching is an environment-friendly alternative to the commonly used and toxic cyanidation protocols for gold extraction from refractory ores. In this paper, we investigate gold and silver bioleaching from porphyry and epithermal mineralisation systems, using iron-oxidizing bacteria Acidithiobacillus ferrooxidans. The invisible Au, sequestered in refractory ores, was characterised in situ by synchrotron micro X-Ray Fluorescence (SR-µ-XRF) and X-ray Absorption Spectroscopy (XAS), offering information on Au unaltered speciation at the atomistic level within the ore matrices and at a micro-scale spatial resolution. The SR-µ-XRF and XAS results showed that 10-20 µm sized elemental Au(0) nuggets are sequestered in pyrite, chalcopyrite, arsenopyrite matrices and at the interface of a mixture of pyrite and chalcopyrite. Moreover, the preliminary bioleaching experiments of the two types of ores, showed that Acidithiobacillus ferrooxidans can catalyse the dissolution of natural heterogeneous Fe-rich geo-matrices, sequestering Au and Ag and releasing particulate phases or partially solubilising them within 60 days. These results provide an understanding of noble metal sequestration and speciation within natural ores and a demonstration of the application of synchrotron-based micro-analysis in characterizing economic trace metals in major mineral structures. This work is a contribution to the ongoing efforts towards finding feasible and greener solutions of noble metal extraction protocols.


Assuntos
Acidithiobacillus , Síncrotrons , Cobre , Metais , Espectroscopia por Absorção de Raios X
4.
Sci Total Environ ; 751: 142235, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-33181987

RESUMO

Inhaled particulate matter (PM) from combustion- and friction-sourced air pollution adversely affects organs distant from the lung. A putative mechanism for the remote effect of inhaled PM is that ultrafine, nano-sized fraction (<100 nm) translocates across the air-tissue barrier, directly interacting with phagocytic tissue cells. Although PM is reported in other tissues, whether it is phagocytosed by non-respiratory tissue resident cells is unclear. Using the placenta as an accessible organ for phagocytic cells, we sought to seek evidence for air pollution-derived PM in tissue resident phagocytes. Macrophage-enriched placental cells (MEPCs) were isolated, and examined by light and electron microscopy. MEPC carbon was assessed by image analysis (mean µm2/1000 cells); particle composition and numbers were investigated using magnetic analyses and energy dispersive X-ray spectroscopy. MEPCs phagocytic capacity was assessed by culture with diesel exhaust PM in vitro. Fifteen placentas were analysed. Black inclusions morphologically compatible with inhaled PM were identified within MEPCs from all samples (mean ± SEM carbon loading, 1000 MEPCs/participant of 0.004 ± 0.001 µm2). High resolution scanning/transmission electron microscopy revealed abundant nano-sized particle aggregates within MEPCs. MEPC PM was predominantly carbonaceous but also co-associated with a range of trace metals, indicative of high temperature (i.e. exogenous) generation. MEPCs contained readily-measurable amounts of iron-rich, ferrimagnetic particles, in concentrations/particle number concentrations ranging, respectively, from 8 to 50 ng/g and 10 to 60.107 magnetic particles/g (wet wt) MEPCs. Extracted MEPCs (n = 20/ placenta) were phagocytic for PM since all cells showed increased carbon area after culture with diesel PM in vitro (mean ± SEM increase 7.55 ± 1.26 µm2 carbon PM). These findings demonstrate that inhaled, metal-bearing, air pollution-derived PM can not only translocate to distant organs, but is taken up by tissue resident phagocytes in vivo. The human placenta, and hence probably the fetus, thus appears to be a target for such particles.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Nanopartículas , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Feminino , Humanos , Tamanho da Partícula , Material Particulado/análise , Gravidez , Emissões de Veículos/análise , Emissões de Veículos/toxicidade
5.
Environ Res ; 176: 108567, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31344533

RESUMO

Air pollution is a risk factor for cardiovascular and Alzheimer's disease (AD). Iron-rich, strongly magnetic, combustion- and friction-derived nanoparticles (CFDNPs) are abundant in particulate air pollution. Metropolitan Mexico City (MMC) young residents have abundant brain CFDNPs associated with AD pathology. We aimed to identify if magnetic CFDNPs are present in urbanites' hearts and associated with cell damage. We used magnetic analysis and transmission electron microscopy (TEM) to identify heart CFDNPs and measured oxidative stress (cellular prion protein, PrPC), and endoplasmic reticulum (ER) stress (glucose regulated protein, GRP78) in 72 subjects age 23.8 ±â€¯9.4y: 63 MMC residents, with Alzheimer Continuum vs 9 controls. Magnetite/maghemite nanoparticles displaying the typical rounded crystal morphologies and fused surface textures of CFDNPs were more abundant in MMC residents' hearts. NPs, ∼2-10 × more abundant in exposed vs controls, were present inside mitochondria in ventricular cardiomyocytes, in ER, at mitochondria-ER contact sites (MERCs), intercalated disks, endothelial and mast cells. Erythrocytes were identified transferring 'hitchhiking' NPs to activated endothelium. Magnetic CFDNP concentrations and particle numbers ranged from 0.2 to 1.7 µg/g and ∼2 to 22 × 109/g, respectively. Co-occurring with cardiomyocyte NPs were abnormal mitochondria and MERCs, dilated ER, and lipofuscin. MMC residents had strong left ventricular PrPC and bi-ventricular GRP78 up-regulation. The health impact of up to ∼22 billion magnetic NPs/g of ventricular tissue are likely reflecting the combination of surface charge, ferrimagnetism, and redox activity, and includes their potential for disruption of the heart's electrical impulse pathways, hyperthermia and alignment and/or rotation in response to magnetic fields. Exposure to solid NPs appears to be directly associated with early and significant cardiac damage. Identification of strongly magnetic CFDNPs in the hearts of children and young adults provides an important novel layer of information for understanding CVD pathogenesis emphasizing the urgent need for prioritization of particulate air pollution control.


Assuntos
Poluentes Atmosféricos/metabolismo , Miocárdio/metabolismo , Nanopartículas/metabolismo , Poluição do Ar/estatística & dados numéricos , Cidades , Chaperona BiP do Retículo Endoplasmático , Exposição Ambiental/estatística & dados numéricos , Fricção , Coração , Humanos , Fenômenos Magnéticos , México , Material Particulado
6.
Environ Sci Technol ; 53(12): 6906-6916, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31095364

RESUMO

Human exposure to airborne ultrafine (≪1 µm) particulate pollution may pose substantial hazards to human health, particularly in urban roadside environments where very large numbers of people are frequently exposed to vehicle-derived ultrafine particles (UFPs). For mitigation purposes, it is timely and important to quantify the deposition of traffic-derived UFPs onto leaves of selected plant species, with particularly efficient particle capture (high deposition velocity), which can be installed curbside, proximal to the emitting vehicular sources. Here, we quantify the size-resolved capture efficiency of UFPs from diesel vehicle exhaust by nine temperate-zone plant species, in wind tunnel experiments. The results show that silver birch (79% UFP removal), yew (71%), and elder (70.5%) have very high capabilities for capture of airborne UFPs. Metal concentrations and metal enrichment ratios in leaf leachates were also highest for the postexposure silver birch leaves; scanning electron microscopy showed that UFPs were concentrated along the hairs of these leaves. For all but two species, magnetic measurements demonstrated substantial increases in the concentration of magnetic particles deposited on the leaves after exposure to the exhaust particulates. Together, these new data show that leaf-deposition of UFPs is chiefly responsible for the substantial reductions in particle numbers measured downwind of the vegetation. It is critical to recognize that the deposition velocity of airborne particulate matter (PM) to leaves is species-specific and often substantially higher (∼10 to 50 times higher) than the "standard" Vd values (e.g., 0.1-0.64 cm s-1 for PM2.5) used in most modeling studies. The use of such low Vd values in models results in a major under-estimation of PM removal by roadside vegetation and thus misrepresents the efficacy of selected vegetation species in the substantial (≫20%) removal of PM. Given the potential hazard to health posed by UFPs and the removal efficiencies shown here (and by previous roadside measurements), roadside planting (maintained at or below head height) of selected species at PM "hotspots" can contribute substantially and quickly to improve in urban air quality and reductions in human exposure. These findings can contribute to the development and implementation of mitigation policies of traffic-derived PM on an international scale.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Idoso , Monitoramento Ambiental , Humanos , Tamanho da Partícula , Material Particulado , Árvores
7.
Nat Geosci ; 11(9): 635-639, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30123317

RESUMO

The Curiosity rover has documented lacustrine sediments at Gale Crater, but how liquid water became physically stable on the early Martian surface is a matter of significant debate. To constrain the composition of the early Martian atmosphere during sediment deposition, we experimentally investigated the nucleation and growth kinetics of authigenic Fe-minerals in Gale Crater mudstones. Experiments show that pH variations within anoxic basaltic waters trigger a series of mineral transformations that rapidly generate magnetite and H2(aq). Magnetite continues to form through this mechanism despite high PCO2 and supersaturation with respect to Fe-carbonate minerals. Reactive transport simulations that incorporate these experimental data show that groundwater infiltration into a lake equilibrated with a CO2-rich atmosphere can trigger the production of both magnetite and H2(aq) in the mudstones. H2(aq), generated at concentrations that would readily exsolve from solution, is capable of increasing annual mean surface temperatures above freezing in CO2-dominated atmospheres. We therefore suggest that magnetite authigenesis could have provided a short-term feedback for stabilizing liquid water, as well as a principal feedstock for biologically relevant chemical reactions, at the early Martian surface.

8.
Proc Natl Acad Sci U S A ; 115(8): 1736-1741, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29432151

RESUMO

In the world-famous sediments of the Chinese Loess Plateau, fossil soils alternate with windblown dust layers to record monsoonal variations over the last ∼3 My. The less-weathered, weakly magnetic dust layers reflect drier, colder glaciations. The fossil soils (paleosols) contain variable concentrations of nanoscale, strongly magnetic iron oxides, formed in situ during the wetter, warmer interglaciations. Mineralogical identification of the magnetic soil oxides is essential for deciphering these key paleoclimatic records. Formation of magnetite, a mixed Fe2+/Fe3+ ferrimagnet, has been linked to soil redox oscillations, and thence to paleorainfall. An opposite hypothesis states that magnetite can only form if the soil is water saturated for significant periods in order for Fe3+ to be reduced to Fe2+, and suggests instead the temperature-dependent formation of maghemite, an Fe3+-oxide, much of which ages subsequently into hematite, typically aluminum substituted. This latter, oxidizing pathway would have been temperature, but not rainfall dependent. Here, through structural fingerprinting and scanning transmission electron microscopy and electron energy loss spectroscopy analysis, we prove that magnetite is the dominant soil-formed ferrite. Maghemite is present in lower concentrations, and shows no evidence of aluminum substitution, negating its proposed precursor role for the aluminum-substituted hematite prevalent in the paleosols. Magnetite dominance demonstrates that magnetite formation occurs in well-drained, generally oxidizing soils, and that soil wetting/drying oscillations drive the degree of soil magnetic enhancement. The magnetic variations of the Chinese Loess Plateau paleosols thus record changes in monsoonal rainfall, over timescales of millions of years.

9.
Proc Natl Acad Sci U S A ; 113(39): 10797-801, 2016 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-27601646

RESUMO

Biologically formed nanoparticles of the strongly magnetic mineral, magnetite, were first detected in the human brain over 20 y ago [Kirschvink JL, Kobayashi-Kirschvink A, Woodford BJ (1992) Proc Natl Acad Sci USA 89(16):7683-7687]. Magnetite can have potentially large impacts on the brain due to its unique combination of redox activity, surface charge, and strongly magnetic behavior. We used magnetic analyses and electron microscopy to identify the abundant presence in the brain of magnetite nanoparticles that are consistent with high-temperature formation, suggesting, therefore, an external, not internal, source. Comprising a separate nanoparticle population from the euhedral particles ascribed to endogenous sources, these brain magnetites are often found with other transition metal nanoparticles, and they display rounded crystal morphologies and fused surface textures, reflecting crystallization upon cooling from an initially heated, iron-bearing source material. Such high-temperature magnetite nanospheres are ubiquitous and abundant in airborne particulate matter pollution. They arise as combustion-derived, iron-rich particles, often associated with other transition metal particles, which condense and/or oxidize upon airborne release. Those magnetite pollutant particles which are <∼200 nm in diameter can enter the brain directly via the olfactory bulb. Their presence proves that externally sourced iron-bearing nanoparticles, rather than their soluble compounds, can be transported directly into the brain, where they may pose hazard to human health.


Assuntos
Poluição do Ar/análise , Encéfalo/metabolismo , Nanopartículas de Magnetita/química , Encéfalo/ultraestrutura , Humanos , Nanopartículas de Magnetita/ultraestrutura , México , Tamanho da Partícula , Espectrometria por Raios X , Espectroscopia de Perda de Energia de Elétrons , Reino Unido
10.
London J Prim Care (Abingdon) ; 8(4): 66-71, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28250836

RESUMO

BACKGROUND: Coronary artery disease is the single most common cause of death in the UK. For those born in Bangladesh but dying in England and Wales, coronary artery disease causes 25% of all deaths. Cost-effective solutions are required to address this burden. Several studies have demonstrated the effectiveness of educational video intervention in informing patients in various settings. SETTING: A Bangladeshi women's group in South London. QUESTIONS: The effectiveness of a health educational video in influencing the knowledge and attitudes towards a preventable illness amongst Bangladeshis in London? The scope of videos for health promotion? METHODS: An educational video on the signs, symptoms and prevention of coronary artery disease was played to a Bangladeshi women's group in South London in the Bengali language. Participants (n = 18, mean age = 53.7) completed a fifteen-question survey to assess their baseline knowledge prior to viewing (pre-test). The group then viewed the video and repeated the initial questionnaire, with additional questions to solicit their attitudes and perceptions (post-test). RESULTS: The intervention significantly improved the basic knowledge of coronary artery disease. There was a statistically significant improvement in the number of correct responses amongst participants with p = 0.0002 (mean change 2.28, 95% CI 1.29-3.27) and in the number of unsure responses p = 0.0042 (mean change 1.83, 95% CI 0.01-3.01). Upon viewing the video, all participants agreed that they wanted to implement the advice from the video into their current lifestyles. CONCLUSION/DISCUSSION: The educational video significantly improved the knowledge and attitudes pertaining to coronary artery disease amongst British-Bangladeshi individuals in the UK community setting. This project illustrated how commissioners may effectively utilise third-sector organisations through partnerships to implement innovative methods of health screening and promotion. Videos are a novel approach of providing culturally sensitive health education to ethnic minority groups, through screening in clinics and in local media.

11.
Water Res ; 67: 276-91, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25286438

RESUMO

The ability of WHAM VII and NICA-Donnan models to predict free-ion activities of Cu in natural waters was examined from two perspectives, (i) the presence of EDTA and NTA contaminants, (ii) the need to improve estimates of HA and FA concentrations. Potentiometric responses of a Cu(II) ion-selective electrode were investigated in five assays containing dissolved organic matter (DOM) isolated from a series of polluted (urban) and relatively unpolluted (upland) streams in northern England. The [Cu]/[DOC] ratio in these assays spanned an environmentally realistic range of ∼1-500 µmol/g. Reasonably good agreement between measured and predicted Cu(2+) activities was obtained with both WHAM VII and NICA-Donnan models, assuming 65% of DOM as fulvic acid and including the measured EDTA and NTA concentrations, but generally the models overestimated the activities by a factor of ∼2. In contrast, the models over-predicted the Cu(2+) activities by up to 2 orders of magnitude at low [Cu]/[DOC] ratios in urban waters if anthropogenic ligands were not included in the model simulations. Three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy was used to measure the functional properties of the isolated DOM and to estimate the fractions of FA and HA present. Using these fractions in the models gave improvements in predictions compared to the 65% FA assumption, as shown by higher correlations, reduced error and reduced bias. These results highlight various issues with the use of the available speciation models for predicting free ion concentrations in natural waters, such as the use of the Biotic Ligand Model (BLM) for the derivation of environmental standards. It is clearly necessary to measure EDTA and NTA in waters with urban influences, while fluorescence measurements offer the possibility of appreciably improving the accuracy of predictions.


Assuntos
Cobre/química , Monitoramento Ambiental/métodos , Substâncias Húmicas/análise , Modelos Químicos , Rios/química , Benzopiranos , Ácido Edético , Inglaterra , Potenciometria , Espectrometria de Fluorescência
12.
Environ Technol ; 35(1-4): 508-13, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24600891

RESUMO

Zero-valent iron (ZVI) and green rusts can be used as reductants to convert chromium from soluble, highly toxic Cr(VI) to insoluble Cr(III). This study compared the reduction rates of Cr(VI) by ZVI and two carbonate green rust phases in alkaline/hyperalkaline solutions. Batch experiments were carried out with synthetic chromate solutions at pH 7.7-12.3 and a chromite ore processing residue (COPR) leachate (pH approximately 12.2). Green rust removes chromate from high pH solutions (pH 10-12.5) very rapidly (<400 s). Chromate reduction rates for both green rust phases were consistently higher than for ZVI throughout the pH range studied; the surface area normalized rate constants were two orders of magnitude higher in the COPR leachate solution at pH 12.2. The performances of both green rusts were unaffected by changes in pH. In contrast, ZVI exhibited a marked decline in reduction rate with increasing pH to become almost ineffective above pH12.


Assuntos
Cromatos/isolamento & purificação , Compostos de Ferro/química , Ferro/química , Minerais/química , Óxidos/química , Rios/química , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Álcalis/química , Cromatos/química , Concentração de Íons de Hidrogênio , Ultrafiltração/métodos , Poluentes Químicos da Água/química
13.
Environ Sci Technol ; 47(23): 13737-44, 2013 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-24215538

RESUMO

Exposure to airborne particulate pollution is associated with premature mortality and a range of inflammatory illnesses, linked to toxic components within the particulate matter (PM) assemblage. The effectiveness of trees in reducing urban PM10 concentrations is intensely debated. Modeling studies indicate PM10 reductions from as low as 1% to as high as ~60%. Empirical data, especially at the local scale, are rare. Here, we use conventional PM10 monitoring along with novel, inexpensive magnetic measurements of television screen swabs to measure changes in PM10 concentrations inside a row of roadside houses, after temporarily installing a curbside line of young birch trees. Independently, the two approaches identify >50% reductions in measured PM levels inside those houses screened by the temporary tree line. Electron microscopy analyses show that leaf-captured PM is concentrated in agglomerations around leaf hairs and within the leaf microtopography. Iron-rich, ultrafine, spherical particles, probably combustion-derived, are abundant, form a particular hazard to health, and likely contribute much of the measured magnetic remanences. Leaf magnetic measurements show that PM capture occurs on both the road-proximal and -distal sides of the trees. The efficacy of roadside trees for mitigation of PM health hazard might be seriously underestimated in some current atmospheric models.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental , Material Particulado/análise , Árvores/química , Emissões de Veículos/análise , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Folhas de Planta/química , Propriedades de Superfície
14.
BMJ Case Rep ; 20132013 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-24045755

RESUMO

Stump appendicitis (SA) is a rare and under-reported complication of open as well as laparoscopic appendicectomy. Diagnosis of SA is often delayed and requires a high index of suspicion in those presenting with signs and symptoms of appendicitis and a history of appendicectomy.We presented a case of SA in a 20-year-old man with a history of open appendicectomy. He was managed conservatively using intravenous antibiotics. The risk of SA is influenced by surgical technique; however, it is unclear whether the incidence is higher with laparoscopic or open procedures. There is little evidence guiding the management of SA with the majority of reported cases treated operatively. This diagnosis should be suspected on the basis of history and examination and CT scanning is a useful tool in most adult cases aiding diagnosis. Management may be guided by the progression of the patient's symptoms either towards operative intervention or a conservative approach.


Assuntos
Apendicectomia , Apendicite/diagnóstico por imagem , Complicações Pós-Operatórias/diagnóstico por imagem , Antibacterianos/uso terapêutico , Apendicite/tratamento farmacológico , Humanos , Masculino , Complicações Pós-Operatórias/tratamento farmacológico , Recidiva , Tomografia Computadorizada por Raios X , Adulto Jovem
15.
Environ Sci Technol ; 47(3): 1487-95, 2013 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-23286231

RESUMO

The harsh chemical conditions involved in the isolation of fulvic acids (FA) and humic acids (HA) have been identified as a possible contributing factor to the significant mismatch between in situ measurements and model predictions of trace metal speciation in freshwaters, resulting from the use of isolated FA and HA in model calibration. A set of experimental assays were developed to enable Cu binding to DOM to be measured over the full range of [Cu]/[DOC] ratios (∼1-460 µmol g(-1)) observed in surface freshwaters. They were applied to the widely used and traditionally isolated Suwannee River HA and FA and to DOM isolated from headwater streams by a mild procedure using minimal chemical treatment. Good agreement was observed between measured free ion activities and those predicted using both WHAM/Model VII and NICA-Donnan speciation models for both traditionally and mildly isolated DOM. Agreement to within a factor of 2 for WHAM/Model VII contrasts with 100-fold differences previously reported between in situ Cu(2+) measurements and model predictions for a wide range of conditions. The results demonstrate that (a) existing speciation models are capable of accurately predicting Cu-humic binding in natural waters at environmentally realistic [Cu]/[DOC] ratios, under equilibrium conditions, and (b) that the isolation procedures traditionally used for HA and FA do not appreciably affect their binding characteristics.


Assuntos
Cobre/análise , Água Doce/química , Compostos Orgânicos/análise , Benzopiranos/análise , Inglaterra , Meio Ambiente , Substâncias Húmicas/análise , Compostos Orgânicos/isolamento & purificação , Solubilidade , Soluções , Poluentes Químicos da Água/análise , Poluição da Água/análise
16.
Langmuir ; 26(9): 6593-603, 2010 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-20180583

RESUMO

The mechanism of green rust sulfate (GR-SO(4)) formation was determined using a novel in situ approach combining time-resolved synchrotron-based wide-angle X-ray scattering (WAXS) with highly controlled chemical synthesis and electrochemical (i.e., Eh and pH) monitoring of the reaction. Using this approach,GR-SO(4) was synthesized under strictly anaerobic conditions by coprecipitation from solutions with known Fe(II)/Fe(III) ratios (i.e., 1.28 and 2) via the controlled increase of pH. The reaction in both systems proceeded via a three-stage precipitation and transformation reaction. During the first stage,schwertmannite (Fe(8)O(8)(OH)(4.5)(SO(4))(1.75)) precipitated directly from solution at pH 2.8-4.5. With increasing pH (>5), Fe(2+) ions adsorb to the surface of schwertmannite and catalyze its transformation to goethite (alpha-FeOOH) during the second stage of the reaction. In the third stage, the hydrolysis of the adsorbed Fe(2+) ions on goethite initiates its transformation to GR-SO(4) at pH >7. The GR-SO(4) then continues to crystallize up to pH approximately 8.5. These results suggest that with an Fe(II)/Fe(III) ratio of < or = 2 in the initial solution the structural Fe(II)/Fe(III) of the GR-SO(4) will be close to that of the starting composition.

17.
Hepatology ; 46(6): 1732-40, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17943989

RESUMO

UNLABELLED: In patients chronically infected with hepatitis C virus (HCV) genotype 4, the optimum duration of therapy and the predictors of sustained virologic response (SVR) have not been adequately determined. In this study, 358 patients with chronic hepatitis C genotype 4 were randomly assigned to pegylated interferon (PEG-IFN) alpha-2b (1.5 mug/kg/week) plus oral ribavirin (10.6 mg/kg/day) for a fixed duration of 48 weeks (control group, n = 50) or for a variable duration (n = 318). In the variable-duration group, patients with undetectable HCV RNA at week 4 were treated for 24 weeks (group A, n = 69), patients with undetectable HCV RNA at week 12 were treated for 36 weeks (group B, n = 79), and the rest of the patients were treated for 48 weeks (group C, n = 160). The primary endpoint was SVR (undetectable HCV RNA 24 weeks after treatment cessation). Groups A-C and the control group had SVR rates of 86%, 76%, 56%, and 58%, respectively. After the study was controlled for predictors, a low baseline histologic grade and stage were associated with SVR (P < 0.029) in all groups. In addition, among patients in group C, older age (P = 0.04), a higher baseline body mass index (P = 0.013), and low baseline HCV RNA (P < 0.001) were also associated with SVR attainment. The incidence of adverse events and the rate of discontinuation were higher in patients in the variable-duration and fixed-duration groups treated for 48 weeks. CONCLUSION: In patients with chronic hepatitis C genotype 4 and undetectable HCV RNA at weeks 4 and 12, treatment with PEG-IFN alpha-2b and ribavirin for 24 weeks and 36 weeks, respectively, is sufficient.


Assuntos
Antivirais/administração & dosagem , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/genética , Interferon-alfa/administração & dosagem , Ribavirina/administração & dosagem , Adulto , Esquema de Medicação , Feminino , Genótipo , Humanos , Interferon alfa-2 , Masculino , Pessoa de Meia-Idade , Polietilenoglicóis , RNA Viral , Proteínas Recombinantes , Carga Viral
18.
South Med J ; 97(10): 1013-4, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15558934

RESUMO

Carbohydrate antigen 125, known as a marker for ovarian cancer, has been reported to be elevated in heart failure caused by left ventricular dysfunction. A case of elevated carbohydrate antigen 125 in isolated right heart failure due to atrial septal defect with preserved left ventricular function is reported.


Assuntos
Antígeno Ca-125/sangue , Baixo Débito Cardíaco/tratamento farmacológico , Comunicação Interatrial/sangue , Idoso , Ascite/diagnóstico por imagem , Baixo Débito Cardíaco/sangue , Baixo Débito Cardíaco/etiologia , Cardiotônicos/uso terapêutico , Digoxina/uso terapêutico , Diuréticos/uso terapêutico , Feminino , Comunicação Interatrial/complicações , Humanos , Ultrassonografia
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