Risk/Benefit Communication about Food-A Systematic Review of the Literature.

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.

Impact of glucose and acetate on the characteristics of the platelet storage lesion in platelets suspended in additive solutions with minimal plasma.

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.

An evaluation of statistical process control techniques applied to blood component quality monitoring with particular reference to CUSUM.

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.

In vitro storage characteristics of platelet concentrates suspended in 70% SSP+(TM) additive solution versus plasma over a 14-day storage period.

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.

Eurobloodpack: a common European design for blood bag systems with integral leucodepletion filters.

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.

Screening of platelets for bacterial contamination at the Welsh Blood Service.

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.

Coronary computed tomography--present status and future directions.

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.

Do continental shelves export organic matter?

It has been suggested that biological production and consumption of organic matter is not balanced in coastal marine ecosystems1,2. If, as suggested, 90% of the phytoplankton produced during the spring bloom period were exported, excess organic carbon would be sequestered on the continental slope below the permanent thermocline. Here we summarize the shelf-edge exchange processes (SEEP) experiment, designed to test the export hypothesis. The absence of a positive imbalance in the organic carbon budget, reinforced by modest sediment deposition and biomass on the continental slope, led us to reject the concept. Only a small fraction of continental shelf phytodetritus is exported; that not consumed in the spring is for the most part used on the continental shelf during the ensuing stratified season. The original hypothesis failed to recognize the contribution of pelagic microbial consumption and the lag in coupling between seasonal production and consumption processes.

Bottom currents in the hudson canyon.

In-place measurements of the bottom currents in the Hudson Canyon reveal that the current regime is characterized by a pronounced reversal of flow up and down the canyon. Velocities are commonly of the order of 8 to 15 centimeters per second, reaching 27 centimeters per second on occasion in the upper and central portion of the canyon. Although alpha 2.5-day recording of currents showed a net transport upcanyon, a combination of 66 current measurements from the submersible Alvin, the analysis of sediment texture and organic carbon, and the determination of the benthic fauna-nutrient relationship indicate that over the long term there is a net transport of fine material through the canyon to the outer continenital rise.

A EuroPrevall review of factors affecting incidence of peanut allergy: priorities for research and policy.

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.

Hemodynamic effects after conversion of arrhythmias.

Systemic and coronary hemodynamic parameters were determined during an arrhythmia and immediately after a direct current transthoracic shock given in an attempt to convert the arrhythmia to a sinus mechanism. No anesthesia or drugs were administered between the two studies. 16 patients with atrial fibrillation converted to sinus rhythm and five did not. In two patients with atrial flutter and one with supraventricular tachycardia, the arrhythmia was corrected. The arrhythmia persisted in a single patient with ventricular tachycardia. Utilizing each patient as his own control, we compared statistically various hemodynamic parameters before and after the shock. In addition, the group of patients whose atrial fibrillation terminated was compared to the group treated in the same manner but in which the atrial fibrillation persisted. Pressures in the right side of the heart decreased in both groups so that the changes appeared to be caused by factors associated with the transthoracic direct current shock or the catheterization procedure. The differences between those with atrial fibrillation who converted to sinus rhythm as compared to those who did not were a decrease in heart rate, an increase in stroke volume, and an increase in cardiac efficiency. There was no immediate effect on the cardiac output or coronary blood flow.

The thermal conductivity of prosthetic sockets and liners.

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.

Computational analysis of models for cotransport.

The order of substrate interaction with a cotransport carrier is studied by numerically fitting theoretical models to empirical data for a Na+-D-glucose pathway. Our analysis is based on a least-squares minimization routine developed at CERN, and uses data derived from tracer flux of substrate under equilibrium exchange conditions. Random, Ordered mirror, and Ordered glide models are considered and the applicability of both Random and Glide systems to the experimental observations is demonstrated. A more detailed study of the Glide model provides an estimation of the relative values of the individual rate constants describing each kinetic step in the mechanism. We argue that parameterization of competing models can result in tests which will distinguish between them, even when these contain many unknowns in the proposed structure of the kinetic mechanism. The essence of this means of model discrimination is the ability to find a single set of parameter values that fits a variety of experimental observations. The ability to obtain numerical estimates of obtain numerical estimates of individual rate constants is also a useful tool in investigation of the kinetic fine structure of the carrier. For the data at hand we conclude that a complete parameterization of the Glide model cannot be attained, possibly due to a heterogeneity in the temperature at which the experiments have been performed. Three solutions to the Glide model are presented, each of which corresponds to a fit of the Glide model to a subset of the experimental data.

Assays of hemolytic toxins.

The ability to produce a cytolytic toxin contributes to the success of many organisms in a particular niche by such diverse means as lysis of a phagolysosomal membrane of the macrophage by hemolysin from the intracellular parasite Trypanosoma cruzi, disruption of leukocyte activity by the Escherichia coli hemolysin, and destruction of invading bacteria by hemolysin from the annelid Glycera dibranchiata. The relative contribution of erythrocyte lysis to survival of the cytolysin producer is still under investigation. Nevertheless, the hemolytic phenotype is both a powerful tool for identifying novel cytolysins and a convenient marker for studying cytolytic activity in established toxins.

Detection and estimation of rheumatic mitral regurgitation in the presence of mitral stenosis by pulsed Doppler echocardiography.

The sensitivity and specificity of pulsed Doppler echocardiography (PDE) in diagnosis and estimation of the severity of mitral regurgitation in the presence of rheumatic mitral stenosis was studied in 34 patients (18 women and 16 men) ranging in age from 33 to 70 years (mean 55). Definitive diagnosis of mitral regurgitation was confirmed in all patients by angiography and in 20 patients also by indicator dilution technique. Mitral regurgitation was detected by PDE in all patients with angiographically proven severe mitral regurgitation and in 7 of 8 patients with moderate mitral regurgitation. In patients with trace to mild mitral regurgitation, PDE was positive in only 7 of 13 patients. When subdivided for mild, moderate and severe mitral regurgitation, PDE sensitivity for diagnosis was 54, 88, and 100%, respectively; overall accuracy was 79% and specificity was 100%. Average systolic dispersion on time-interval histogram was 59% for mild, 89% for moderate, and 100% for severe mitral regurgitation. Groups of patients with mild mitral regurgitation could be differentiated from those with moderate (p less than 0.05) and severe (p less than 0.01) mitral regurgitation. A significant overlap of individual values, however, occurred. In 7 of 11 patients with moderate to severe mitral regurgitation, systolic turbulence also was detected in the left atrium. PDE was sensitive and specific in diagnosing moderate to severe mitral regurgitation in the presence of mitral stenosis. Assessment of precise severity of mitral regurgitation is still a problem in individual patients.

Hemodynamic effects of controlled degrees of coronary artery stenosis in short-term and long-term studies in dogs.

Coronary and aortic blood flow, aortic and distal coronary blood pressure were measured with electromagnetic flowmeters and pressure gauges in 15 anesthetized dogs with the chest left open. Increasing degrees of known, fixed, partial coronary artery obstruction were applied with concentric plastic cylinders 3 mm. in length and with varying internal diameters. Because these plastic cylinders are radiolucent and can also be permanently implanted, postoperative arteriograms were taken to evaluate the degree of stenosis produced. At necropsy the degree of obstruction was checked by ligating and removing the narrowed vessel and examining a histologic section of a stenosed portion. The reactive hyperemic response to a 20 second complete occlusion was recorded with amounts of obstruction varying from 10 to 90 per cent. The reactive hyperemia began to decrease with an average of 36 +/- 10 per cent stenosis. A pressure gradient of 10 mm. Hg across the obstruction occurred with an average of 57 +/- 8 per cent stenosis. The reactive hyperemic response was abolished with an average of 75 +/- 6 per cent stenosis, and with greater degrees of stenosis the total flow began to decrease below control levels. The phasic coronary flow pattern was also altered with increasing amounts of fixed partial obstruction. As the per cent of stenosis was increased, the ratio of diastolic to systolic coronary flow decreased. When reactive hyperemia was abolished, very little diastolic-to-systolic variation remained.

Diagnosis and management of the hypothyroid patient with chest pain.

A retrospective analysis of 38 patients undergoing cardiac catheterization with the diagnoses of hypothyroidism and chest pain revealed 23 to be euthyroid while receiving replacement therapy and 15 to be hypothyroid. Cardiac index was significantly reduced (p less than 0.01) in hypothyroid and euthyroid patients with thyroxine values between 4 and 7 micrograms/dl (2.8 +/- 0.7 and 3.0 +/- 0.9 L/min/m2, respectively), compared to euthyroid patients with thyroxine values greater than 7 micrograms/dl with or without coronary artery disease (4.0 +/- 1.2 and 4.0 +/- 0.7 L/min/m2, respectively). Ten hypothyroid patients underwent coronary artery bypass. There were no deaths, and only one patient required prolonged postoperative intubation. With a mean follow-up of 36 months, there have been no myocardial infarctions and one late death, which occurred at 7 years secondary to stroke. We conclude that preoperative thyroid replacement therapy is theoretically dangerous and may not significantly improve hemodynamics until full replacement is achieved. Coronary bypass grafting can be performed safely despite hypothyroidism with excellent early results.

Computerized fluoroscopy: new technique for the noninvasive evaluation of the aorta, coronary artery bypass grafts, and left ventricular function.

A computerized fluoroscopy system has been developed on the basis of real-time digital processing of x-ray transmission data from traditional image-intensified fluoroscopy equipment. High-quality visualization of any part of the arterial system is obtained following intravenous injection of 0.5 to 0.75 ml/kg of iodinated contrast materials. This report describes the use of this technique to evaluate the aortic arch, left ventricular function, and coronary artery bypass graft patency. Fifty intravenous studies were performed in 25 patients. Among 20 patients with coronary artery bypass grafts, computerized fluoroscopy correctly identified 11 of 15 patent grafts and 11 of 11 occluded grafts as confirmed by standard coronary arteriography in 11 of these patients. Unlike computerized tomography, our technique gives a longitudinal view of the bypass graft much like direct coronary angiography. Aortic arch studies included demonstration of a right aortic arch with a small left subclavian artery, a coarctation, and a normal aortic arch in a trauma patient with a wide mediastinum. Segmental wall motion abnormalities were clearly identified by a modification of the technique which produces a negative outline on the ventriculogram in dyskinetic segments. Ejection fractions may be calculated by determining the amount of iodine in the ventricle in systole and diastole. This technique may also be used to evaluate carotid disease and peripheral vascular disease in patients undergoing coronary artery bypass procedures. Computerized fluoroscopy, therefore, allows evaluation of the entire cardiovascular system by the relatively noninvasive technique of intravenous angiography.

Computerized fluoroscopy techniques for intravenous study of cardiac chamber dynamics.

A computerized fluoroscopy system which was recently developed in our laboratories permits image contrast increases of 8-16 relative to conventional image intensifer fluoroscopy and permits study of canine and human ventricular wall motion using peripheral intravenous injections. Two time-dependent image subtraction algorithms are illustrated in connection with observation of artificially infarcted dog hearts. The first algorithm produces a display analogous to direct ventriculography using catheterization. The second displays regions of dyskinetic motion as anomalous image grey shades.

Carpentier ring annuloplasty in severe noncalcific mitral insufficiency.

Sixteen patients have undergone Carpentier ring annuloplasty for severe mitral insufficiency (MI) since 1974. Our criteria were clinical and angiographic evidence of severe noncalcific MI, a dilated mitral anulus, absence of severe subvalvular chordal thickening, and no major loss of leaflet substance. Carpentier annuloplasty has been successful in eliminating MI in every patient except one. There have been no embolic problems and no early or late deaths. From 1971 to 1974, a similar group of 20 patients with the same diagnosis underwent prosthetic valve replacement. Even though all patients were receiving anticoagulant drugs, three had emboli and there were one early and three late deaths. In patients with severe noncalcific MI who meet our criteria, Carpentier ring annuloplasty is preferable to valve replacement, thus eliminating the hazards of a prosthesis and of long-term anticoagulant therapy.