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1.
Environ Sci Technol ; 56(15): 11051-11060, 2022 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-35861449

RESUMO

Methods for identifying origin, movement, and foraging areas of animals are essential for understanding ecosystem connectivity, nutrient flows, and other ecological processes. Telemetric methods can provide detailed spatial coverage but are limited to a minimum body size of specimen for tagging. In recent years, stable isotopes have been increasingly used to track animal migration by linking landscape isotope patterns into movement (isoscapes). However, compared to telemetric methods, the spatial resolution of bulk stable isotopes is low. Here, we examined a novel approach by evaluating the use of compound-specific hydrogen and carbon stable isotopes of fatty acids (δ2HFA and δ13CFA) from fish liver, muscle, brain, and eye tissues for identifying site specificity in a 254 km2 sub-alpine river catchment. We analyzed 208 fish (European bullhead, rainbow trout, and brown trout) collected in 2016 and 2018 at 15 different sites. δ13CFA values of these fish tissues correlated more among each other than those of δ2HFA values. Both δ2HFA and δ13CFA values showed tissue-dependent isotopic fractionation, while fish taxa had only small effects. The highest site specificity was for δ13CDHA values, while the δ2H isotopic difference between linoleic acid and alpha-linolenic acid resulted in the highest site specificity. Using linear discrimination analysis of FA isotope values, over 90% of fish could be assigned to their location of origin; however, the accuracy dropped to about 56% when isotope data from 2016 were used to predict the sites for samples collected in 2018, suggesting temporal shifts in site specificity of δ2HFA and δ13CFA. However, the predictive power of δ2HFA and δ13CFA over this time interval was still higher than site specificity of bulk tissue isotopes for a single time point. In summary, compound-specific isotope analysis of fatty acids may become a highly effective tool for assessing fine and large-scale movement and foraging areas of animals.


Assuntos
Ecossistema , Ácidos Graxos , Animais , Isótopos de Carbono , Isótopos de Nitrogênio/análise , Truta
2.
Rapid Commun Mass Spectrom ; 36(7): e9259, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35040224

RESUMO

RATIONALE: The isotopic composition (δ15 N, δ18 O) of nitrate in fruits and vegetables differentiates organic from conventional food production practices. Organic systems do not use synthetic nitrate fertilizers high in 18 O and low in 15 N and thereby help reveal producers' fertilization claims. Isotope analyses of nitrate extracted from fruits and vegetables are done by bacterial reduction which is costly and by specialized laboratories. Rapid, low-cost methods are needed to promulgate nitrate isotope analyses of food products to support organic food product certification and to verify the authenticity of production claims. METHODS: Fresh strawberry samples were obtained from certified organic and conventional growers in Andalucía, Spain. We applied a new, rapid, one-step Ti(III) reduction method to convert the nitrate from strawberry extracts to N2 O gas for headspace isotope analyses using isotope-ratio mass spectrometry. Using the Ti(III) reduction method, 70 samples, controls and references were prepared and analyzed for NO3 - , δ15 N and δ18 O per 48 h. We also analyzed extracts and solids for anions and cations and for bulk δ15 N for multivariate chemometric evaluation. RESULTS: The Ti(III)-based isotope analyses of nitrate in strawberry extracts revealed clear differentiation between organic and conventional production with mean δ18 O and δ15 N values of +18.3 ± 1.2 ‰ and +17.6 ± 1.2 ‰ versus +28.2 ± 4.5 ‰ and +14.9 ± 3.0 ‰, respectively. The δ15 N of strawberry dry mass differed slightly (+3.0 ± 1.4 ‰ versus +4.0 ± 1.4 ‰) between organic and conventional samples, respectively. Chemometric analyses of nitrate isotopes and extract chemistry revealed that the δ18 O of nitrate along with δ15 N and Ca2+ fully differentiated organic from conventional strawberry production. CONCLUSIONS: Our results show the Ti(III) reduction method provides a new low-cost and rapid analytical method to facilitate compound-specific δ15 N and δ18 O isotope analyses of nitrate in selected fruit types, and likely other food products, for the purposes of assessing nitrate fertilization practices of organic versus conventional production claims and to support authenticity investigations.


Assuntos
Frutas , Nitratos , Frutas/química , Nitratos/análise , Isótopos de Nitrogênio/análise , Isótopos de Oxigênio/análise , Extratos Vegetais/análise , Titânio
3.
Rapid Commun Mass Spectrom ; 35(19): e9164, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34270817

RESUMO

RATIONALE: A widespread problem observed in global water isotope (δ18 O, δ2 H) proficiency tests is compromised working reference materials due to storage-dispensing evaporation effects. Proper storage requires no evaporation or leakage, which causes isotopic drift and bias. Surveys by the International Atomic Energy Agency (IAEA) show most isotope laboratories use glass or plastic bottles to store working reference materials, with frequent opening and closings that pose evaporation risks. Practical small (ca. 2-5 L) storage-dispensing solutions free of air exposure, evaporation, and leakage are needed. We also tested several smaller-scale bottles for day-to-day aliquots. METHODS: We tested low-cost, conveniently sized (4 L) adaptations of a common stainless-steel beverage keg with a liquid dispenser, with minor modifications to facilitate low-flow dispensing and pressurization (1-2 bar) with Ar or N2 . We tested three kegs (100%, 75%, 50% initial fills) for a 2-year period along with monthly dispensing to assess long-term storage viability for maintaining δ18 O and δ2 H integrity and dispensing, and day-to-day aliquot bottles for 6 months. RESULTS: Test results showed these small keg storage systems fully maintained the isotopic integrity of water over the 2-year testing period with no trend in the isotopic data that would reveal evaporative loss or leakage (e.g., pressure or mass loss) regardless of starting fill level. However, evaporated water in the outlet tube assembly must be eliminated by discarding 15-20 mL before dispensing into appropriate daily-use laboratory standard bottles (30-100 mL). Glass bottles for daily aliquots showed good integrity properties, but only if their fill level was >50%. CONCLUSIONS: The use of a low-cost pressurized metal beverage keg dispensing system provides a robust solution to enable laboratories to maintain the integrity of their water isotope working reference materials over several years.

4.
Rapid Commun Mass Spectrom ; 34(17): e8832, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32415697

RESUMO

RATIONALE: Tritium (3 H) is an important hydrological tracer that has been commonly used for over 60 years to evaluate water residence times and water dynamics in shallow/recent groundwaters, streams, lakes and the ocean. We tested the analytical performance of 78 international laboratories engaged in low-level 3 H assays for water age dating and monitoring of environmental waters. METHODS: Seven test waters were distributed by the IAEA to 78 international tritium laboratories. Set 1 included a tritium-free groundwater plus three ultra-low 3 H samples (0.5-7 TU) for meeting groundwater dating specifications. Set 2 contained three higher 3 H-content samples (40-500 TU) suitable for testing of environmental monitoring laboratories. RESULTS: Seventy of the laboratories used liquid scintillation counting with or without electrolytic enrichment, seven utilized 3 He accumulation and mass spectrometry, and one used gas-proportional counting. Only ~50% of laboratories demonstrated the ability to generate accurate 3 H data that was precise enough for water age dating purposes. CONCLUSIONS: The proficiency test helped identify recurrent weaknesses and potential solutions. Strategies for performance improvements of 3 H laboratories include: (a) improved quantification of 3 H detection limits and analytical uncertainty, (b) stricter quality control practices in routine operations along with care and recalibration of 3 H standards traceable to primary NIST standards, (c) annual assessment of tritium enrichment factors and instrumental performance, and (d) for water age dating purposes the use of electrolytic enrichment systems having the highest possible 3 H enrichment factors (e.g. >50×).

5.
Int J Qual Stud Health Well-being ; 15(1): 1713657, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31924131

RESUMO

Background: Widows are socioeconomically disadvantaged, especially in low resource regions. Childless widows are a group whose plight may be worse given sociocultural circumstances. In the current study, we examined the lived experiences of childless widows living in remote Nigeria, highlighting this group as being in critical need for social interventions.Method: Childless widows (n = 11) in rural settings in South East Nigeria were interviewed. Narrative analysis was used in navigating the lived experiences of the widows.Results: Extreme distress, ostracism, stigma, and traumatic experiences were common in the narratives of the widows. However, childlessness was at the core of their distress. Treated as outcasts, the widows resigned to God, though some were scarcely allowed to play supportive roles among relatives. As social welfare packages are almost non-existent in this region, religious groups often played supportive roles.Conclusion: Legislation protecting widows are good but may not be sufficient if it does not translate to improved wellbeing/welfare for widows. Childless widows, especially those in rural areas, are especially vulnerable as they face peculiar deprivation and psychological distress arising from cultural/social realities. Recognising the limited resources in low income countries, mobilisation of local structures and resources to educate and monitor local communities are important.


Assuntos
Relações Familiares/etnologia , Angústia Psicológica , População Rural , Marginalização Social , Viuvez/etnologia , Viuvez/psicologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Narração , Nigéria/etnologia , Paridade
6.
JOR Spine ; 1(4): e1040, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31463455

RESUMO

INTRODUCTION: Anterior cervical discectomy and fusion has been associated with the development of adjacent segment degeneration (ASD), with clinical incidence of approximately 3% per year. Cervical total disc arthroplasty (TDA) has been proposed as an alternative to prevent ASD. HYPOTHESES: TDA in optimal placement using an elastic-core cervical disc (RHINE, K2M Inc., Leesburg, Virginia) will replicate natural kinematics and will improve with optimal vs anterior placement. METHODS: Seven C3-T1 cervical cadaver spines were tested intact first, then after one-level TDA at C5-C6 anterior placement, after TDA at C5-C6 optimal placement, after two-level TDA at C5-C6 and C6-C7 optimal placement, and finally after two-level TDA at C5-C6 lateral placement and C6-C7 optimal placement. The specimens were subjected to: Flexion-Extension moments (+1.5 Nm) with compressive preloads of 0 N and 150 N, lateral bending (LB) and axial rotation (AR) (+1.5 Nm) without preload. RESULTS: C5-C6 TDA in optimal placement resulted in a non-significant increase in flexion-extension ROM compared to intact under 0 N and 150 N preload (P > 0.05). Both LB and AR ROM decreased with arthroplasty (P < 0.01). Optimal placement of C6-C7 TDA resulted in an increase in flexion-extension ROM with preload compared to intact (P < 0.05) while LB and AR ROM decreased with arthroplasty (P < 0.01). CONCLUSION: This six degree of freedom elastic-core disc arthroplasty effectively restored flexion-extension motion to intact levels. In LB the TDA maintained 42% ROM at C5-C6 and 60% at C6-C7. In AR 57% of the ROM was maintained at C5-C6 and 70% at C6-C7. These findings are supported by literature which shows cervical TDA results in restoration of approximately 50% ROM in LB and AR, which is a multifactorial phenomenon encompassing TDA design parameters and anatomical constraints. Anterior placement of this viscoelastic TDA device shows motion restoration similar to optimal placement suggesting its design may be less sensitive to suboptimal placement.

7.
Med Devices (Auckl) ; 9: 223-30, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27471414

RESUMO

INTRODUCTION: Supplemental posterior instrumentation has been widely used to enhance stability and improve fusion rates in higher risk patients undergoing anterior cervical discectomy and fusion (ACDF). These typically involve posterior lateral mass or pedicle screw fixation with significant inherent risks and morbidities. More recently, cervical cages placed bilaterally between the facet joints (posterior cervical cages) have been used as a less disruptive alternative for posterior fixation. The purpose of this study was to compare the stability achieved by both posterior cages and ACDF at a single motion segment and determine the stability achieved with posterior cervical cages used as an adjunct to single- and multilevel ACDF. METHODS: Seven cadaveric cervical spine (C2-T1) specimens were tested in the following sequence: intact, C5-C6 bilateral posterior cages, C6-C7 plated ACDF with and without posterior cages, and C3-C5 plated ACDF with and without posterior cages. Range of motion in flexion-extension, lateral bending, and axial rotation was measured for each condition under moment loading up to ±1.5 Nm. RESULTS: All fusion constructs significantly reduced the range of motion compared to intact in flexion-extension, lateral bending, and axial rotation (P<0.05). Similar stability was achieved with bilateral posterior cages and plated ACDF at a single level. Posterior cages, when placed as an adjunct to ACDF, further reduced range of motion in both single- and multilevel constructs (P<0.05). CONCLUSION: The biomechanical effectiveness of bilateral posterior cages in limiting cervical segmental motion is comparable to single-level plated ACDF. Furthermore, supplementation of single- and multilevel ACDF with posterior cervical cages provided a significant increase in stability and therefore may be a potential, minimally disruptive option for supplemental fixation for improving ACDF fusion rates.

8.
Spine (Phila Pa 1976) ; 40(14): E814-22, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25943082

RESUMO

STUDY DESIGN: Cadaveric study to accurately measure lumbar neuroforaminal area and height throughout the flexion-extension range of motion (ROM). OBJECTIVE: Create a new computed tomography (CT)-based specimen-specific model technique to provide insight on the effects of kinematics on lumbar neuroforamen morphology during flexion-extension ROM. SUMMARY OF BACKGROUND DATA: Nerve root compression is a key factor in symptomatic progression of degenerative disc disease because these changes directly affect neuroforaminal area. Traditional techniques to evaluate the neuroforamen suffer from poor accuracy, have inherent limitations, and fail to provide data throughout the ROM. METHODS: Six cadaveric specimens (L1-sacrum) were instrumented with radiopaque spheres and CT scanned. 3-Dimensional reconstructions were made of each vertebra and the sphere locations determined. During kinematic testing, the spheres were located in relation to optoelectronic targets attached to each vertebra. The result was a 3-dimensional representation of the specimen's CT reconstruction moving in response to experimental data. Bony contours of the L2-L3 and L4-L5 neuroforamen were digitized producing continuous neuroforaminal area and height data throughout the ROM. RESULTS: Neuroforaminal area and height linearly increased in flexion and decreased in extension. There was significant correlation between flexion-extension motion and percent change in area (L2-L3: 3.1%/deg, R = 0.94, L4-L5: 2.5%/deg, R = 0.90) and neuroforaminal height (L2-L3: 2.1%/deg, R = 0.95, L4-L5: 1.6%/deg, R = 0.93). Regression analysis showed that the ratio between neuroforaminal height and area is at least 1:1.5 such that a 100% increase in height is associated with an area increase of more than 150%. CONCLUSION: This is the first study to measure lumbar neuroforaminal area and height throughout flexion-extension ROM. The CT-based specimen-specific model technique can accurately evaluate the effect of kinematics on morphological features of the spine. The demonstrated increase in neuroforaminal dimension in flexion is consistent with treatment modalities used in clinical therapies to relieve radicular symptoms. LEVEL OF EVIDENCE: N/A.


Assuntos
Imageamento Tridimensional/métodos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiologia , Modelos Biológicos , Tomografia Computadorizada por Raios X/métodos , Adulto , Fenômenos Biomecânicos , Humanos , Pessoa de Meia-Idade
9.
Cardiol Rev ; 23(2): 53-68, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25436468

RESUMO

With advances in care, increasing numbers of people with hemophilia (PWH) achieve near-normal life expectancies and present with typical age-related cardiovascular conditions. Evidence-based guidelines for medical or surgical management of cardiovascular conditions in individuals with hemophilia are limited. Published recommendations exist for the management of some common cardiovascular conditions (eg, ischemic heart disease, atrial fibrillation), but identifying optimal strategies for anticoagulant or antithrombotic therapy constitutes the primary challenge of managing nonoperative cardiovascular disease (CVD) in PWH. In general, as long as factor concentrates or other hemostatic therapies maintain adequate hemostasis, the recommended medical and surgical management of CVD in PWH parallels that in individuals without hemophilia. The presence of factor inhibitors complicates hemophilia management. Published outcomes of CVD treatment in PWH are similar to those in the general population. Specific knowledge about factor replacement, factor inhibitors, and disease-specific treatment distinguishes the cardiovascular care of PWH from similar care of individuals without this rare bleeding disorder. Furthermore, a multidisciplinary approach incorporating a hematologist with an onsite coagulation laboratory, ideally associated with a hemophilia treatment center, is integral to the management of CVD in PWH.


Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Fármacos Cardiovasculares/farmacologia , Doenças Cardiovasculares , Hemofilia A , Hemofilia B , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/tratamento farmacológico , Consenso , Gerenciamento Clínico , Hemofilia A/sangue , Hemofilia A/complicações , Hemofilia A/tratamento farmacológico , Hemofilia B/sangue , Hemofilia B/complicações , Hemofilia B/tratamento farmacológico , Humanos , Conduta do Tratamento Medicamentoso
11.
Ecol Appl ; 18(4): 965-82, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18536256

RESUMO

Dissolved O2 concentration and delta18O-O2 diel curves can be combined to assess aquatic photosynthesis, respiration, and metabolic balance, and to disentangle some of the confounding factors associated with interpretation of traditional O2 concentration curves. A dynamic model is used to illustrate how six key environmental and biological parameters interact to affect diel O2 saturation and delta18O-O2 curves, thereby providing a fundamental framework for the use of delta18O-O2 in ecosystem productivity studies. delta18O-O2 provides information unavailable from concentration alone because delta18O-O2 and saturation curves are not symmetrical and can be used to constrain gas exchange and isotopic fractionation by eliminating many common assumptions. Changes in key parameters affect diel O2 saturation and delta18O-O2 curves as follows: (1) an increase in primary production and respiration rates increases the diel range of O2 saturation and delta18O-O2 and decreases the mean delta18O-O2 value; (2) a decrease in the primary production to respiration ratio (P:R) decreases the level of O2 saturation and increases the delta18O-O2 values; (3) an increase in the gas exchange rate decreases the diel range of O2 saturation and delta18O-O2 values and moves the mean O2 saturation and delta18O-O2 values toward atmospheric equilibrium; (4) a decrease in strength of the respiratory isotopic fractionation (alphaR closer to 1) has no effect on O2 saturation and decreases the delta18O-O2 values; (5) an increase in the delta18O of water has no effect on O2 saturation and increases the minimum (daytime) delta18O-O2 value; and (6) an increase in temperature reduces O2 solubility and thus increases the diel range of O2 saturation and delta18O-O2 values. Understanding the interplay between these key parameters makes it easier to decipher the controls on O2 and delta18O-O2, compare aquatic ecosystems, and make quantitative estimates of ecosystem metabolism. The photosynthesis to respiration to gas exchange ratio (P:R:G) is better than the P:R ratio at describing and assessing the vulnerability of aquatic ecosystems under various environmental stressors by providing better constrained estimates of ecosystem metabolism and gas exchange.


Assuntos
Ritmo Circadiano , Ecossistema , Consumo de Oxigênio , Oxigênio/análise , Água/análise , Isótopos de Oxigênio/análise , Temperatura
12.
Liver Transpl ; 13(9): 1330-8, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17763388

RESUMO

The purposes of liver transplantation (LT) include the extension of survival, improvement in quality of life, and the return of the recipient as a contributing member of society. Employment is one measure of the ability to return to society. The aim of this study is to determine the factors affecting employment/subemployment after LT. A total of 308 adult liver transplant recipients who were seen at the University of California, Los Angeles were administered the Medical Outcomes Short Form 36 (SF-36) and a questionnaire regarding work history and insurance coverage. Multivariate analysis were used to identify independent variables associated with posttransplantation employment. Interaction terms were used to examine effect modification. Of 308 transplant recipients, 218 (70.8%) worked prior to transplantation, and 78 (27%) worked posttransplantation. Pretransplant variables that were independently associated with posttransplantation employment included the following: lack of disability income (odds ratio [OR] = 1.86; 95% confidence interval [CI], 1.32-7.18; P = 0.36); health maintenance organization (HMO)/preferred provider organization (PPO) insurance (OR = 3.08; 95% CI, 1.32-7.18; P < 0.01); the number of hours worked (OR = 1.17; 95% CI, 1.08-1.28; P < 0.01); and the lack of diabetes mellitus (OR = 0.23; 95% CI, 0.70-0.73; P < 0.01). An interaction term between disability income and hours worked prior to transplantation (OR = 0.16; 95 % CI, 0.03-0.83; P = 0.03) was independently associated with posttransplantation employment. In a separate regression model of SF-36 responses, posttransplantation physical functioning (OR = 1.17; 95% CI, 1.10-1.26; P < 0.01) and role-physical (OR = 1.1; 95% CI, 1.02-1.16; P < 0.01) were independently associated with employment after transplantation. In conclusion, HMO or PPO insurance, lack of disability income coverage prior to transplant, the absence of diabetes mellitus, the number of hours worked prior to transplantation, and high physical functioning were associated with posttransplantation employment.


Assuntos
Emprego , Transplante de Fígado/fisiologia , Qualidade de Vida , Adulto , Idoso , Escolaridade , Etnicidade , Feminino , Seguimentos , Humanos , Renda , Transplante de Fígado/psicologia , Masculino , Análise de Regressão , Inquéritos e Questionários , Estados Unidos
13.
Braz. arch. biol. technol ; Braz. arch. biol. technol;50(3): 445-459, May 2007. ilus, tab
Artigo em Inglês | LILACS | ID: lil-459979

RESUMO

Positron emission tomography (PET) is a non-invasive nuclear imaging technique. In PET, radiolabelled molecules decay by positron emission. The gamma rays resulting from positron annihilation are detected in coincidence and mapped to produce three dimensional images of radiotracer distribution in the body. Molecular imaging with PET refers to the use of positron-emitting biomolecules that are highly specific substrates for target enzymes, transport proteins or receptor proteins. Molecular imaging with PET produces spatial and temporal maps of the target-related processes. Molecular imaging is an important analytical tool in diagnostic medical imaging, therapy monitoring and the development of new drugs. Molecular imaging has its roots in molecular biology. Originally, molecular biology meant the biology of gene expression, but now molecular biology broadly encompasses the macromolecular biology and biochemistry of proteins, complex carbohydrates and nucleic acids. To date, molecular imaging has focused primarily on proteins, with emphasis on monoclonal antibodies and their derivative forms, small-molecule enzyme substrates and components of cell membranes, including transporters and transmembrane signalling elements. This overview provides an introduction to nucleosides, nucleotides and nucleic acids in the context of molecular imaging.


A tomografia por emissão de pósitrons (TEP) é uma técnica de imagem não invasiva da medicina nuclear. A TEP utiliza moléculas marcadas com emissores de radiação beta positiva (pósitrons). As radiações gama medidas que resultam do aniquilamento dos pósitrons são detectadas por um sistema de coincidência e mapeadas para produzir uma imagem tridimensional da distribuição do radiotraçador no corpo. A imagem molecular com TEP refere-se ao uso de biomoléculas marcadas com emissor de pósitron que são substratos altamente específicos para alvos como enzimas, proteínas transportadoras ou receptores protéicos. A imagem molecular com TEP produz mapas espaciais e temporais de alvos que estejam sendo avaliados. A imagem molecular é uma importante ferramenta analítica no diagnóstico por imagem em medicina, no monitoramento de terapia e no desenvolvimento de novas drogas. A imagem molecular tem seus fundamentos na biologia molecular. Originalmente, a biologia molecular significava a biologia da expressão gênica, mas atualmente a biologia molecular envolve amplamente a biologia de macromoléculas, a bioquímica de proteínas, carboidratos complexos e ácidos nucléicos. A imagem molecular tem priorizado as proteínas, com ênfase nos anticorpos monoclonais e suas formas derivadas, substratos enzimáticos para pequenas moléculas e componentes de membranas celulares, incluindo os transportadores e elementos envolvidos com a sinalização trans-membrana.

14.
J Environ Qual ; 35(5): 1884-93, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16973630

RESUMO

Fish are commonly used for monitoring the quality of waters receiving pulp mill effluents (PMEs). Isotopic assays of fish tissues have the potential to provide empirical evidence to link an effluent source to exposure. We show in a 45-d factorial laboratory experiment that different exposure pathways lead to isotopic signatures in fish tissue. Rainbow trout (Oncorhynchus mykiss) were exposed to 10% PME in three ways; direct exposure through addition of PME to aquaria, indirect exposure through invertebrate food consumption (Chironomus tentans cultured in 10% PME), and a combination of both exposure pathways. Of the four stable isotopes measured (delta13C, delta15N, delta34S, delta37Cl), delta13C, delta34S, and delta37Cl showed significant differences in exposed animal tissues. Delta37Cl of fish muscle tissue showed consistent differences across trophic levels and revealed contrasting pathways of PME exposure. Contrasting delta 37Cl values in C. tentans due to the presence or absence of 10% PME did not translate into delta37Cl differences in fish. Rather, delta37Cl ratios of fish muscle tissue were specifically related to 10% PME exposure in the aquaria (waterborne exposure pathway). Feasible distributions of 37Cl source contributions for observed mixture ratios confirmed that PME accounted for observed differences in delta37Cl among treatments. Direct uptake of chloride ions across gill surfaces is the most likely pathway for assimilation of PME into fish tissues. Considering the variability of PMEs and receiving environments, use of a multi-isotope approach is recommended for tracing exposure of fish. Use of 37Cl should also be considered in light of its alternative assimilation pathway.


Assuntos
Bioensaio , Monitoramento Ambiental , Oncorhynchus mykiss/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Radioativos da Água/metabolismo , Animais , Bioensaio/métodos , Chironomidae/metabolismo , Monitoramento Ambiental/métodos , Radioisótopos/análise , Radioisótopos/metabolismo , Fatores de Tempo
15.
J Health Soc Behav ; 47(2): 156-72, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16821509

RESUMO

Using data from a sample of 1,136 adults ages 65 and older in the District of Columbia and two adjoining counties in Maryland, we examine the association between neighborhood structural disadvantage and levels of anger. In addition, we test whether subjective financial comparisons with neighbors modify those effects differently for elders at different levels of income. We find that the association between neighborhood disadvantage and anger is positive among lower-income elders who feel financially advantaged relative to their neighbors. In contrast, the association between neighborhood disadvantage and anger is positive among higher-income elders who feel financially disadvantaged relative to their neighbors. Irrespective of income, neighborhood disadvantage is unrelated to anger among people who feel financially similar to their neighbors. We discuss the implications of our findings for the study of neighborhood context and health, underscoring interrelationships among inequality, social comparisons, and the stress process.


Assuntos
Ira , Idoso Fragilizado/psicologia , Características de Residência/classificação , Justiça Social , Problemas Sociais/psicologia , Apoio Social , Populações Vulneráveis/psicologia , Idoso , Idoso de 80 Anos ou mais , Efeitos Psicossociais da Doença , Depressão/economia , Depressão/epidemiologia , District of Columbia/epidemiologia , Feminino , Idoso Fragilizado/estatística & dados numéricos , Humanos , Entrevistas como Assunto , Masculino , Maryland/epidemiologia , Áreas de Pobreza , Problemas Sociais/economia , Fatores Socioeconômicos , Estresse Psicológico/economia , Estresse Psicológico/epidemiologia , Populações Vulneráveis/estatística & dados numéricos
16.
J Health Soc Behav ; 47(1): 17-31, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16583773

RESUMO

This paper focuses on financial strain across the life course as a condition underlying health inequalities observed in later life. The analysis is based on data from 1167 adults 65 years and older collected as part of the 'Aging, Stress and Health Study". Relying on retrospective data about hardship experienced over the life course, we find that long-term financial hardship is reflected in a range of health outcomes at late life, even after controlling for the effects of current financial circumstances. Moreover, the sheer persistence of hardship matters more than its episodic occurrence or timing, so that the health effects of early hardship may be obviated if followed by no further hardship. This pattern offindings is consistent with the notion of allostatic load, the cumulative damage done to health and well-being under the burden of an unrelenting stressor in a critically important life domain.


Assuntos
Nível de Saúde , Classe Social , Idoso , Envelhecimento , District of Columbia , Feminino , Humanos , Entrevistas como Assunto , Masculino , Maryland
17.
Rev Epidemiol Sante Publique ; 53 Spec No 1: 1S31-8, 2005 Sep.
Artigo em Francês | MEDLINE | ID: mdl-16327738

RESUMO

BACKGROUND: For pertinent investigation of patient satisfaction it is important to know what type of data collection procedure yields optimal results. In this study, we compared a self- versus interview administration of the European Organisation for Research and Treatment of Cancer (EORTC) patient satisfaction questionnaire (QLQ-SAT32), noting response and item omission rates. We also assessed the correlation and agreement between responses according to these modalities of questionnaire administration. METHODS: 123 patients recruited in two anti-cancer Centers in France were asked to complete the QLQ-SAT32 at home within 2 weeks of hospital discharge and were randomly allocated to participate in a telephone interview-administration of the QLQ-SAT32, either before or after self-completing the QLQ-SAT32. RESULTS: 104 patients completed both modalities of questionnaire administration. Agreement proved excellent for the doctors' and nurses' subscales and satisfactory for the services' subscale and the general satisfaction single item. However, a significant difference in response rate showed up between Centers (different interviewers) and the interview modality revealed an item omission rate higher than for the self-administration modality. CONCLUSION: Self- and interview-administration of the QLQ-SAT32 provided similar responses however different response rate between interviewers and higher item omission rate in interviews suggests a biasing effect of that modality of data collection.


Assuntos
Neoplasias , Satisfação do Paciente , Inquéritos e Questionários , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Coleta de Dados/métodos , Feminino , França , Humanos , Masculino , Pessoa de Meia-Idade
18.
J Aging Health ; 17(5): 634-60, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16177454

RESUMO

OBJECTIVES: This study examines the ways in which the sense of mastery modifies the association between economic hardship experienced at different life stages and late-life depression, anxiety, and physical symptoms. METHODS: Using data from a sample of 1,167 older adults, ordinary least squares regression techniques were used to estimate the main and mastery-contingent effects of economic hardship. RESULTS: Results underscore the dual role of the sense of mastery in the stress process. First, mastery mediates the effects of both earlier- and later-life economic hardships on elders' current physical and mental health. Second, mastery moderates the health impact of economic hardship, although those patterns depend on the period of economic hardship and health outcome. DISCUSSION: Integrating the stress process model and a life course perspective, the authors argue that to fully understand protective capacity of psychosocial resources, stressors encountered at different life stages should be taken into account.


Assuntos
Adaptação Psicológica , Idoso , Nível de Saúde , Controle Interno-Externo , Pobreza/psicologia , Estresse Psicológico , Ansiedade , Depressão , Humanos , Análise dos Mínimos Quadrados , Fatores Socioeconômicos
19.
J Health Soc Behav ; 46(2): 205-19, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16028458

RESUMO

This article proposes several conceptual perspectives designed to advance our understanding of the material and experiential conditions contributing to persistent disparities in rates of morbidity and mortality among groups unequal in their social and economic statuses. An underlying assumption is that these disparities, which are in clear evidence at mid- and late life, may be anchored to earlier circumstances of the life course. Of particular interest are those circumstances resulting in people with the least privileged statuses having the greatest chances of exposure to health-related stressors. Among the stressors closely linked to status and status attainment are those that continue or are repeated across the life course, such as enduring economic strain and discriminatory experiences. Also taking a long-range toll on health are circumstances of stress proliferation, a process that places people exposed to a serious adversity at risk for later exposure to additional adversities. We suggest that this process can be observed in instances of trauma, in early out-of-sequence transitions, and in the case of undesired changes that disrupt behaviors and relationships in established roles. Effective effort to close the systemic health gaps must recognize their structural underpinnings.


Assuntos
Nível de Saúde , Acontecimentos que Mudam a Vida , Estresse Psicológico , Envelhecimento , Humanos , Classe Social , Estados Unidos
20.
Liver Transpl ; 11(2): 218-23, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15666392

RESUMO

Previous studies have demonstrated an association between Child Turcotte-Pugh (CTP) class and impaired quality of life. However, the relationship between the model for end-stage liver disease (MELD) score and quality of life (QOL) has not been well studied. In this study, quality of life questionnaires (Medical Outcomes Short Form 36 [SF-36] and the Chronic Liver Disease Questionnaire [CLDQ]) were administered to 150 adult patients awaiting liver transplantation. We also collected demographic data and laboratory results and recorded manifestations of hepatic decompensation. The study found that all domains of the SF-36 and CLDQ were significantly lower in our patient cohort than in normal controls (P < .001). There was a moderate negative correlation between CPT class and physical components of the SF-36 (r = -.30), while there was a weak negative correlation (r = -.10) between CPT class and the mental component. There was a negative moderate correlation between CPT class and overall CLDQ (r = -.39, P < .001) and a weak correlation (r = -.20) between MELD score and overall CLDQ score. Both encephalopathy (correlation coefficient = -.713, P = .004) and ascites (correlation coefficient = -.68, P = .006) were predictive of the QOL using CLDQ (adjusted R(2) = .1494 and f = 0.000). In conclusion, in liver transplant candidates, the severity of liver disease assessed by the MELD score was not predictive of QOL. The presence of ascites and/or encephalopathy was significantly associated with poor quality of life. CTP correlates better to QOL, probably because it contains ascites and encephalopathy.


Assuntos
Indicadores Básicos de Saúde , Transplante de Fígado , Qualidade de Vida , Obtenção de Tecidos e Órgãos , Feminino , Humanos , Cirrose Hepática/cirurgia , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários
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