RESUMO
A systematic review relevant to the following research questions was conducted (1) the extent to which different theoretical frameworks have been applied to food risk/benefit communication and (2) the impact such food risk/benefit communication interventions have had on related risk/benefit attitudes and behaviors. Fifty four papers were identified. The analysis revealed that (primarily European or US) research interest has been relatively recent. Certain food issues were of greater interest to researchers than others, perhaps reflecting the occurrence of a crisis, or policy concern. Three broad themes relevant to the development of best practice in risk (benefit) communication were identified: the characteristics of the target population; the contents of the information; and the characteristics of the information sources. Within these themes, independent and dependent variables differed considerably. Overall, acute risk (benefit) communication will require advances in communication process whereas chronic communication needs to identify audience requirements. Both citizen's risk/benefit perceptions and (if relevant) related behaviors need to be taken into account, and recommendations for behavioral change need to be concrete and actionable. The application of theoretical frameworks to the study of risk (benefit) communication was infrequent, and developing predictive models of effective risk (benefit) communication may be contingent on improved theoretical perspectives.
Assuntos
Análise Custo-Benefício , Inocuidade dos Alimentos , Comunicação Persuasiva , Bases de Dados Factuais , Humanos , Medição de Risco , Fatores de RiscoRESUMO
BACKGROUND AND OBJECTIVES: Glucose and acetate have been proposed to be required elements in platelet storage media. This study investigated the role of these compounds on the varied elements that comprise the platelet storage lesion. MATERIALS AND METHODS: For each replicate, four pooled and split ABO group-specific buffy coat-derived platelet concentrates were suspended in an in-house additive solution with minimal plasma and varying final concentrations of acetate or glucose. Units were sampled on days 2, 3, 6, 8 and 10 and tested for markers of platelet morphology, activation, function, metabolism and indicators of cell death. RESULTS: The absence of glucose was associated with a decrease in ATP, falling to a mean of 1·1 ± 0·1 µmol/10(11) plts in units with no added glucose compared with 4·2 ± 0·6 µmol/10(11) plts (P < 0·001) in units with 30 mm glucose. As glucose became depleted, the decrease in ATP to levels below 3 µmol/10(11) plts was associated with an increase in both annexin V binding and intracellular free calcium. In units lacking exogenous acetate, ATP levels on day 10 were 5·2 ± 1·5 µmol/10(11) plts compared with 2·7 ± 0·9 µmol/10(11) plts in units with 56 mm acetate (P = 0·006). Higher concentrations of exogenous acetate were associated with a lower hypotonic shock response and higher surface expression of CD62P suggestive of a dose dependency. CONCLUSION: Under current physical storage conditions, glucose appears necessary for the maintenance of platelets stored as concentrates in minimal volumes of plasma. The addition of acetate was associated with increased platelet activation and reduced ATP levels.
Assuntos
Ácido Acético/farmacologia , Plaquetas/metabolismo , Preservação de Sangue/métodos , Glucose/farmacologia , Indicadores e Reagentes/farmacologia , Plasma , Ativação Plaquetária/efeitos dos fármacos , Sistema ABO de Grupos Sanguíneos , Trifosfato de Adenosina/metabolismo , Plaquetas/patologia , Humanos , Edulcorantes , Fatores de TempoRESUMO
BACKGROUND: There is recognition of the importance of measuring patients' experiences, expectations and satisfaction. OBJECTIVES: To assess the literature on the concept and measurement of patients' expectations for health care, and to develop and test a measure of patients' expectations, using adult patients in community, general practice and hospital outpatient departments in Greater London, Norwich and Essex, UK. DATA SOURCES: Major electronic databases including the British Nursing Index, EMBASE, MEDLINE, PsycINFO and the Applied Social Sciences Index and Abstracts were searched between 2000 and 2009. REVIEW METHODS: Narrative review, semi-structured exploratory study and surveys of GP patients and hospital outpatients immediately before and after their surgery/clinic visit to measure their pre-visit expectations for their health care and their post-visit experiences (expectations met and satisfaction with visit) (site specific). RESULTS: A total of 20,439 titles and 266 abstracts were identified, of which 211 were included in the review. Most research designs were weak, with small or selected samples, and a theoretical frame of reference was rarely stated. The origin of questions about expectations was often absent, questions were frequently untested and those with reported reliability or validity data had generally mixed results. In the survey data the expectations measures met acceptability criteria for reliability; all exceeded the threshold of α = 0.70, in each mode of administration and sample type. Items and subscales also correlated at least moderately with those variables that they were expected to be associated with, supporting their validity. The item means within subscales were generally similar between samples and all-item-total correlations exceeded the acceptability threshold. Descriptive findings revealed that most patients ideally expected cleanliness, information about where to go, convenient and punctual appointments and helpful reception staff, the doctor to be knowledgeable, clear and easy to understand, to be involved in treatment decisions and to experience a reduction in symptoms/problems. Expectations least likely to be met included being seen on time and choice of hospital/doctor (items requested by the ethics committee). Other items that had low met expectations included helpfulness of reception staff, doctor being respectful and treating with dignity (hospital sample), doctor knowledgeable (hospital), being given reassurance, receiving advice about health/condition, information about cause and management of condition and information about benefits/side effects of treatment, being given an opportunity to discuss problems, and the three items on outcome expectancies. Previous consultations/experiences of health services and health-care staff/professionals most commonly influenced expectations. Overall, pre-visit realistic expectations were lower than patients' ideals or hopes. Most post-visit experiences indicated some unmet expectations (e.g. cause and management of health/condition, benefits/side effects of treatments) and some expectations that were exceeded. Generally, GP patients reported higher pre-visit expectations and post-visit met expectations. Correlations between subscale domains were strongest between the structure and process of health care, doctor-patient communication style and doctor's approach to giving information, all common indicators of the quality of health care, supporting the validity of the measures. The post-visit experiences subscale significantly predicted single-item summary ratings of overall met expectations and satisfaction. GP rather than hospital patients were also independently predictive of expectations met. Other predictors were having no/little anxiety/depression, older age (satisfaction) and fewer effects of health on quality of life (met expectations). LIMITATIONS: The surveys in clinics were based on convenience, not random sampling methods. CONCLUSIONS: These findings have implications for establishing the quality of health services and informing their improvement. Awareness of the patient's met and unmet expectations should enable staff to understand the patient's perspective and improve communication. This study examined the perspective of the patient only; it is not possible to examine the extent to which any expectations might have been unrealistically too high or too low. This is a challenge for future research. FUNDING: The National Institute for Health Research Health Technology Assessment programme and the National Co-ordinating Centre for Research Methodology (NCCRM).
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Atenção à Saúde , Pesquisas sobre Atenção à Saúde/normas , Satisfação do Paciente , Adulto , Idoso , Idoso de 80 Anos ou mais , Inglaterra , Feminino , Hospitalização , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente/estatística & dados numéricos , Psicometria , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Statistical process control (SPC) is used to monitor the performance of blood component collection and production processes in the UK and elsewhere. The sensitivity of the applied technique(s) needs to be matched to the clinical importance of the parameter being monitored such that significant deviations in the process mean and/or variability of critical parameters (e.g. the leucocyte content of leucodepleted components) are detected and investigated immediately. AIMS: This study assessed the sensitivity and specificity of a range of techniques for variable and attribute (proportion non-conforming) data. MATERIALS AND METHODS: Comparison was based on a range of simulated and 'live' blood component quality monitoring data including X/R, cumulative sum (CUSUM) procedures, the scan statistic and np charts. RESULTS: X/R and CUSUM could detect shifts of two standard deviations in the process mean within 5 days. Current leucocyte count data (substantially skewed even after log transformation) was found to be better suited to attribute analysis. CUSUM alone was able to detect shifts on the same day when based on 20 or more samples and achieved acceptable specificity. CONCLUSIONS: CUSUM procedures for proportion non-conforming can usefully augment existing X/R techniques for leucodepletion monitoring, provide valid control limits and the required sensitivity. The scan statistic and 'np' charts offered no obvious advantages.
Assuntos
Transfusão de Componentes Sanguíneos/métodos , Segurança do Sangue , Sistemas Computadorizados de Registros Médicos , Modelos Estatísticos , Controle de Qualidade , Transfusão de Componentes Sanguíneos/instrumentação , Feminino , Humanos , Masculino , Reino UnidoRESUMO
The use of coronary computed tomography angiography (cCTA) is growing rapidly, in large part because of fast-paced technical innovations that have increased diagnostic accuracy while providing new opportunities for radiation dose reduction. cCTA using recent generation CT scanners has been repeatedly shown to have excellent negative predictive value for ruling out significant coronary stenosis in comparison with invasive coronary angiography (ICA) and is now accepted for this use in selected populations. Current work is increasingly focused on evaluating and optimising radiation dose reduction techniques, the cost-effectiveness of cCTA implementation, and the impact of cCTA on patient management and outcomes. In addition, the potential value of emerging applications, such as atherosclerotic plaque characterisation and myocardial perfusion and viability assessment, are undergoing intense investigation.
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Angiografia Coronária/métodos , Angiografia Coronária/tendências , Doença da Artéria Coronariana/diagnóstico por imagem , Tomografia Computadorizada por Raios X , HumanosRESUMO
Three EBA specified blood bag configurations ('Eurobloodpack') are described which are capable of meeting >80% of its member's requirements. These include a 'top-and-top' and two 'bottom-and-top' packs enabling aseptic, pre-donation collection of up to 40 ml of samples, 427.5-522.5 ml of whole blood and the preparation of an extensive range of blood components. Features currently beyond the scope of ISO standardisation have been controlled including: anticoagulant and additive volumes; collection needle and sampling system; transfer tubing; cross-match line; base label; leucodepletion filter performance; compatibility of access ports and transfusion sets. Eurobloodpack has significant advantages for blood services and blood bag manufacturers.
Assuntos
Transfusão de Componentes Sanguíneos/instrumentação , Transfusão de Componentes Sanguíneos/normas , Doadores de Sangue , Procedimentos de Redução de Leucócitos/instrumentação , Procedimentos de Redução de Leucócitos/normas , União Europeia , HumanosRESUMO
BACKGROUND AND OBJECTIVES: The non-paired two-arm study compared the in vitro storage characteristics of platelets suspended as concentrates in either 100% plasma or a mixture of additive solution (SSP+™, MacoPharma, Mouveaux, France) and autologous plasma in a 70:30 ratio over a 14-day storage period. MATERIALS AND METHODS: The buffy coat-derived pooled platelet concentrates were sampled on days 1, 2, 3, 6, 8, 10 and 14 and tests performed to determine platelet morphology, function, metabolism, activation and apoptosis-like activity. RESULTS: Swirling remained strong (score=3) in SSP+™, whilst scores of 1 and 0 were noted for plasma units by end of storage. In contrast to units in plasma, pH levels remained above seven in SSP+™ units, increasing after day 10. Percent positive expression of CD62P was similar in both groups on day 1 (median of 54% and 56% for plasma (n=13) and SSP+™ (n=12), respectively), with SSP+™ units showing a more moderate increase in activation after day 10. A progressive decrease in mitochondrial membrane potential was evident in both groups from day 1, whilst annexin V binding was relatively stable from days 1 to 3, with median values remaining below 6%. Subsequent to this, the percentage of platelets binding annexin V increased to approximately 30% by day 14. CONCLUSION: Platelets suspended in a medium of 70:30 SSP+™ to plasma ratio performed at least as well as platelets in 100% autologous plasma for up to 10 days of storage. Further, results are suggestive of an apoptosis-like process being involved in the platelet storage lesion.
Assuntos
Plaquetas , Preservação de Sangue/métodos , Soluções para Preservação de Órgãos , Plasma Rico em Plaquetas , Plaquetas/metabolismo , Humanos , Ativação Plaquetária , Plasma Rico em Plaquetas/metabolismoRESUMO
BACKGROUND AND OBJECTIVE: This report details the results of the implementation of a bacterial screening system at the Welsh Blood Service and provides an estimate of the levels of bacterial contamination at the time of sampling. MATERIALS AND METHODS: Apheresis (Caridian BCT) and buffy coat-derived pooled platelet components were sampled on day 1 for bacterial contamination and the sample was monitored throughout the lifespan of the platelet component. Unused platelet components were re-tested to determine the effectiveness of the screening. Results from the BacT/ALERT are uploaded to the in-house Blood Establishment Computer System (BECS) every 12 min. Positive alerts are automatically sent to staff, facilitating a timely intervention. RESULTS: Between February 2003 and March 2010 the screening system tested 54 828 platelets and detected 257 (1 in 213) initial positives of which 35 (1 in 1567, 0·06%) were confirmed [95% confidence interval (CI), 0·04-0·08%]. Additionally, screening of 6438 unused platelet components detected another 6 (1 in 1073, 0·09%) confirmed positives not detected during initial testing (95% CI, 0·02-0·16%). Analysis of the data suggests that on day 1 the number of bacteria in such platelet component packs was between 5 and 62 cfus total. Day 1 culture has a sensitivity of 40%. CONCLUSIONS: The bacterial screening system has removed a significant number, but not all bacterially contaminated platelet components from the supply. The sample volume is an important factor in sensitivity due to the low number of bacteria in a platelet component pack on day 1. An effective notification and recall system is a critical part of the bacterial screening system.
Assuntos
Armazenamento de Sangue/métodos , Plaquetas/microbiologia , Automação , Técnicas Bacteriológicas , Bancos de Sangue/normas , Buffy Coat , Remoção de Componentes Sanguíneos , Transfusão de Sangue/normas , Notificação de Doenças , Transmissão de Doença Infecciosa/prevenção & controle , Humanos , Reino UnidoRESUMO
OBJECTIVES: To develop a psychometrically valid Patient Preferences Questionnaire for Angina treatment (PPQA). SETTING: Seven general practices across England in 2007. SUBJECTS: Convenience sample of 383 patients with diagnosed angina. METHOD: Postal self-administered questionnaire survey using the full-length PPQA. This comprised 54 items about the three main treatment modalities for angina: medication, angioplasty and coronary artery bypass grafting. RESULTS: The full PPQA was reduced to 18 items, six for each of the three subscales (treatment modalities), by standard psychometric methods. The reduced PPQA was psychometrically sound and valid, although confirmatory factor analyses with a larger sample are required. CONCLUSION: The PPQA is a potentially useful instrument to help clinicians understand patients' angina treatment preferences.
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Angina Pectoris/terapia , Preferência do Paciente , Atenção Primária à Saúde , Idoso , Inglaterra , Feminino , Medicina Geral , Humanos , Masculino , Psicometria , Inquéritos e Questionários , Reino UnidoRESUMO
Peanuts are extensively cultivated around the world, providing a foodstuff that is both cheap to produce and nutritious. However, allergy to peanuts is of growing global concern, particularly given the severity of peanut-allergic reactions, which can include anaphylaxis and death. Consequently, it is important to understand the factors related to the prevalence of peanut allergy in order to inform efforts to ameliorate or pre-empt the condition. In this article we review evidence for the relevance of factors hypothesized to have some association with allergy prevalence, including both genetic and environmental factors. Although our analysis does indicate some empirical support for the importance of a number of factors, the key finding is that there are significant data gaps in the literature that undermine our ability to provide firm conclusions. We highlight these gaps, indicating questions that need to be addressed by future research.
Assuntos
Alérgenos/imunologia , Antígenos de Plantas/imunologia , Arachis/imunologia , Hipersensibilidade a Amendoim/epidemiologia , Exposição Ambiental , Europa (Continente)/epidemiologia , Manipulação de Alimentos/métodos , Predisposição Genética para Doença , Humanos , Hipersensibilidade a Amendoim/genética , PrevalênciaRESUMO
In developing and implementing appropriate food risk management strategies, it is important to understand how consumers evaluate the quality of food risk management practices. The aim of this study is to model the underlying psychological factors influencing consumer evaluations of food risk management quality using structural equation modeling techniques (SEM), and to examine the extent to which the influence of these factors is country-specific (comparing respondents from Denmark, Germany, Greece, Slovenia, and the United Kingdom). A survey was developed to model the factors that drive consumer evaluations of food risk management practices and their relative importance (n= 2,533 total respondents). The measurement scales included in the structural model were configurally and metrically invariant across countries. Results show that some factors appear to drive perceptions of effective food risk management in all the countries studied, such as proactive consumer protection, which was positively related to consumers' evaluation of food risk management quality, while opaque and reactive risk management was negatively related to perceived food risk management quality. Other factors appeared to apply only in certain countries. For example, skepticism in risk assessment and communication practices was negatively related to food risk management quality, particularly so in the UK. Expertise of food risk managers appeared to be a key factor in consumers' evaluation of food risk management quality in some countries. However, trust in the honesty of food risk managers did not have a significant effect on food risk management quality. From the results, policy implications for food risk management are discussed and important directions for future research are identified.
Assuntos
Alimentos , Gestão de Riscos , Animais , Participação da Comunidade , Europa (Continente) , Alimentos/efeitos adversos , Alimentos/normas , Abastecimento de Alimentos/normas , Humanos , Modelos Estatísticos , Análise de Regressão , Gestão de Riscos/normas , Gestão de Riscos/estatística & dados numéricos , Segurança , ConfiançaRESUMO
Elevated stump skin temperatures and the accompanying thermal discomfort are side effects of prosthesis use that may reduce amputee quality of life, particularly in hot or humid surroundings. Lower skin temperatures might be achieved through more effective heat transfer in the prosthesis, a process governed in part by the thermal conductivity of the sock, liner, and socket layers. To assess the thermodynamic properties of currently available components, an instrument capable of measuring the heat flux across a regulated temperature differential was developed. Experimental results show that the thermal conductivity ranged from 0.085 - 0.266 W/m x K for liner materials and from 0.148 - 0.150 W/m x K for socket materials. The results of this study demonstrate that the prescription of typical multi-layer prostheses constructed with the higher thermal conductivity materials might reduce temperature-related discomfort in patients.
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Próteses e Implantes , Amputados , Humanos , Teste de Materiais , Desenho de Prótese , Temperatura Cutânea , Condutividade TérmicaRESUMO
Defining boundaries between populations is often difficult in the absence of information about current levels of gene flow. Such definitions can be important, however, both for the understanding of population dynamics and for conservation planning. Recently developed Bayesian methods for analysing genetic data now provide a powerful approach to this problem. Natterjack toads Bufo calamita are endangered in Britain, where their distribution is restricted to four geographically discrete regions. In three of these regions the boundaries between populations are often uncertain. We therefore used Bayesian approaches with microsatellite data to try and define British natterjack population structure, and thus inform conservation management. A large sample of natterjack toads from all 38 locations in Britain where the species is native was genotyped at eight microsatellite loci. The genetic diversity of natterjack populations declined as a function of increasing latitude, echoing postglacial colonization dynamics. Comparisons of three assignment methods (structure, baps and geneland) generated some broad similarities but also some inconsistencies in the definitions of population structure, especially in the most complex region (south Cumbria). Implications of the analyses for the future conservation of Bufo calamita in Britain are discussed.
Assuntos
Bufonidae/genética , Demografia , Fluxo Gênico/genética , Variação Genética , Genética Populacional , Animais , Teorema de Bayes , Conservação dos Recursos Naturais , Frequência do Gene , Geografia , Repetições de Microssatélites/genética , Modelos Genéticos , Dinâmica Populacional , Reino UnidoRESUMO
The present study examined the thesis that positive affect may serve to broaden the scope of attentional filters, reducing their selectivity. The effect of positive mood states was measured in two different cognitive domains: semantic search (remote associates task) and visual selective attention (Eriksen flanker task). In the conceptual domain, positive affect enhanced access to remote associates, suggesting an increase in the scope of semantic access. In the visuospatial domain, positive affect impaired visual selective attention by increasing processing of spatially adjacent flanking distractors, suggesting an increase in the scope of visuospatial attention. During positive states, individual differences in enhanced semantic access were correlated with the degree of impaired visual selective attention. These findings demonstrate that positive states, by loosening the reins on inhibitory control, result in a fundamental change in the breadth of attentional allocation to both external visual and internal conceptual space.
Assuntos
Afeto , Atenção , Adulto , Feminino , Humanos , Masculino , Semântica , Análise e Desempenho de TarefasRESUMO
BACKGROUND AND OBJECTIVES: A filter (PRF1) designed to remove abnormal prion proteins from red-cell units has been developed. The purpose of this study was to evaluate the quality of red cells produced using this device. MATERIALS AND METHODS: Leucocyte-depleted red-cell units (CPD, CPD-A1 and CPD/SAGM) processed according to standard UK practices were filtered using PRF1. Filtered and control units were stored and sampled on day 1, day 7 and on the date of expiry and were tested using standard measures of red-cell quality. RESULTS: Filtered units were found to have significantly higher percentage haemolysis levels, lower haemoglobin levels and a smaller volume compared with controls. All results, however, were well within the permitted 0.8% haemolysis level at the end of storage and all units met the UK guidelines for haemoglobin and volume. The other test parameters measured showed no significant differences between the test and control units. CONCLUSIONS: The PRF1 filter was found to be easy to use and resulted in red-cell units that met all relevant UK and European Guidelines.
Assuntos
Transfusão de Eritrócitos , Hemofiltração , Procedimentos de Redução de Leucócitos , Plasma/química , Proteínas PrPC/química , HumanosRESUMO
In a recent series of papers, Murray et al. have put forward a number of important ideas regarding the measurement of inequalities in health. In this paper we agree with some of these ideas but draw attention to one key aspect of their approach--measuring inequalities on the basis of small area data--which is flawed. A numerical example is presented to illustrate the problem. An alternative approach drawing on longitudinal data is outlined, which preserves and enhances the most desirable aspects of their proposal. These include the use of a life course perspective, and the consideration of non-fatal health outcomes as well as the more usual information on mortality patterns.
Assuntos
Pesquisa sobre Serviços de Saúde/métodos , Estudos Longitudinais , Análise de Pequenas Áreas , Justiça Social/estatística & dados numéricos , Fatores Socioeconômicos , Análise de Variância , Estudos de Coortes , Indicadores Básicos de Saúde , Humanos , Tábuas de Vida , Mortalidade , Avaliação de Resultados em Cuidados de Saúde , Classe SocialRESUMO
This article evaluates the nine empirical studies that have been conducted on expert versus lay judgments of risk. Contrary to received wisdom, this study finds that there is little empirical evidence for the propositions (1) that experts judge risk differently from members of the public or (2) that experts are more veridical in their risk assessments. Methodological weaknesses in the early research are documented, and it is shown that the results of more recent studies are confounded by social and demographic factors that have been found to correlate with judgments of risk. Using a task-analysis taxonomy, a template is provided for the documentation of future studies of expert-lay differences/similarities that will facilitate analytic comparison.
RESUMO
Mucins in ulcerative colitis and colon cancer share common properties of reduced sulfation and increased oncofetal carbohydrate antigen expression. It has previously been shown that there is no simple correlation between these changes and the activity of the relevant glycosyl-, sialyl-, and sulfo-transferases. We examined mucin sulfation and expression of oncofetal Thomsen-Friedenreich (TF) antigen (galactosyl beta1-3N-acetylgalactosamine alpha-) in the goblet cell-differentiated human colon cancer cell line LS174T following treatment with bafilomycin A(1, )which raises intra-Golgi pH, or monensin, which disrupts medial-trans Golgi transport. Cells were dual-labeled with sodium [(35)S]-sulfate and D-[6-(3)H(N)]-glucosamine hydrochloride, or labeled with L-[U-(14)C]-threonine alone. Mucin was purified using Sepharose CL-4B gel filtration. Mucin sulfo-Lewis(a) and TF antigen expression were assessed using the F2 anti-sulfo-Lewis(a) monoclonal antibody and peanut agglutinin binding respectively. Bafilomycin (0.01 microM; 48 h) reduced total mucin sulfation, expressed relative to incorporation of glucosamine, to 0.50 +/- 0.04 d.p.m. [(35)S]-sulfate per d.p.m. [(3)H]-glucosamine compared to control, 0.84 +/- 0.05 (p < 0.001, n = 16). This was accompanied by 50.3 +/- 8.0% increased expression of TF antigen (p < 0.01) and 50.1 +/- 5.5% decreased expression of sulfo-Lewis(a) (p < 0.01). The reduced sulfate:glucosamine ratio was largely due to increased incorporation of glucosamine into newly synthesized mucin rather than reduction in total sulfate incorporation. In contrast, monensin only reduced total mucin glycosylation at concentrations > 0.1 microM and had no significant effect on mucin sulfation or TF expression. Intra-Golgi alkalinization affects mucin glycosylation, resulting in decreased mucin sulfation and increased expression of TF antigen, changes that mimic those seen in cancerous and premalignant human colonic epithelium.
Assuntos
Antígenos Glicosídicos Associados a Tumores/metabolismo , Neoplasias do Colo/metabolismo , Células Caliciformes/metabolismo , Macrolídeos , Mucinas/metabolismo , Antibacterianos/farmacologia , Sequência de Carboidratos , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , DNA de Neoplasias/metabolismo , Glucosamina/metabolismo , Glicosilação/efeitos dos fármacos , Células Caliciformes/imunologia , Células Caliciformes/patologia , Complexo de Golgi/efeitos dos fármacos , Complexo de Golgi/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Antígenos do Grupo Sanguíneo de Lewis , Dados de Sequência Molecular , Monensin/farmacologia , Mucinas/química , Oligossacarídeos/metabolismo , Sulfatos/metabolismo , Células Tumorais CultivadasRESUMO
Hypoxia (oxygen concentration less than 2 mg L-1 or 62.5 mmol m-3) occurs on the Louisiana continental shelf during summer when the consumption of oxygen by sediment and water column respiration exceed resupply by photosynthesis and mixing. Biological processes that consume or produce oxygen have been summarized in a budget that can be used to quantify the degree to which consumption in deep water and in the sediments exceeds net production and thus the time it takes to reach hypoxic conditions following the spring onset of stratification. The net consumption rate by the sea floor biota (sediment oxygen consumption, SOC) is inversely related to oxygen concentration and directly related to temperature. Photosynthesis is of potential importance throughout the deep water column and on the sea floor when light is adequate. A non-steady state, time-dependent numerical simulation model is used to compare biological and physical processes with shipboard measurements and continuous near-bottom records. The simulations illustrate possible variations in oxygen concentration on time scales of hours to months, and these in general match much of the variability in the direct observations at time scales of days to weeks. The frequently observed unremitting anoxia lasting weeks at some locations is not produced in the present simulations. A possible explanation is the chemical oxidation in the water column of reduced metabolic end-products produced in the sediments by anaerobic metabolism. Direct measurements of biological processes could lead to better understanding of how extrinsic forcing functions can best be managed to improve water quality.