226Ra/238U disequilibrium in an upland organic soil exhibiting elevated natural radioactivity.

This paper presents the results of a study into the anomalous 226Ra/238U disequilibrium (226Ra/238U of 0.5-9) exhibited by an upland organic soil in Co. Donegal, Ireland. Radiochemical speciation of 226Ra, 238U and 225Ra indicates that in this organic soil the high 226Ra/238U ratio is due to loss of 235U relative to 226Ra via oxidation and mobilisation of 238U in the upper layers of the soil and subsequent loss in solution. At the lower, more reducing depths of the soil profile, 238U and 226Ra are essentially in equilibrium. Loss of 238U appears to occur primarily from the easily oxidised organic and iron oxide fractions of the soil, samples exhibiting high 226Ra/238U ratios displaying significantly lower 238U levels in these fractions than samples whose ratio is below the average value for the soil of the valley. Selective enrichment of 226Ra by plants or preferential leaching of 226Ra from the underlying rock is not supported by the results of this study.

Nonangiographic assessment of coronary artery disease: a practical approach to optical coherence tomography and fractional flow reserve.

In an era of increased scrutiny of the appropriateness and safety of revascularization, interventional cardiologists must evolve by adding key tools to their armamentarium. This review highlights the utility of optical coherence tomography and fractional flow reserve in the catheterization lab and provides a practical guide for using these technologies during coronary intervention in various lesion subsets. We propose that fractional flow reserve informs the decision to intervene and optical coherence tomography guides the optimization of the outcome.

Esophageal dilation with integrated balloon imaging: initial evaluation in a porcine model.

BACKGROUND: When treating achalasia, balloon dilation is often combined with fluoroscopy to allow the lower esophageal sphincter to be visualized as it is being dilated. We sought to evaluate a new balloon dilation technology, EsoFLIP, which allows the shape of the balloon to be visualized in a nonradiographic manner by using impedance planimetry electrodes located within the dilation balloon. METHODS: Two pigs weighing 35 kg were used. The EsoFLIP balloon dilator was introduced under endoscopic visualization. Successive injections of 50, 60, 70 and 85 mL into the dilation balloon permitted dilations at increasing diameters to be achieved. Following each dilation fluid was withdrawn to leave 30 mL in the balloon and an EsoFLIP image was captured to track progressive dilation of the gastroesophageal junction (GEJ). RESULTS: The EsoFLIP catheter was safely deployed in the two pigs and no complications were noted. For pig 1, during dilation, the measured balloon diameter at the waist was 24.1, 28.9, 29.2 and 30.0 mm for balloon dilation volumes of 50, 60, 70 and 85 mL respectively. For pig 2 the corresponding diameter at the waist was 22.8, 27.1, 28.5 and 29.4 mm. The GEJ diameter increased from 12.5 and 12.4 mm to 17.4 and 17.5mm for pigs 1 and 2 respectively. Distensibility of the GEJ in pig 1 increased from 2.3 mm(2)/mmHg before to 4.4 mm(2)/mmHg after dilation and in pig 2 from 4.4 to 9.6 mm(2)/mmHg. The GEJ substantively achieved its final diameter after the dilation using just 50 mL in the balloon. CONCLUSIONS: We demonstrated technical feasibility and safety of the EsoFLIP dilator in a porcine model. Further studies in humans with achalasia remain to be conducted, which, besides demonstrating technical feasibility, should also evaluate the use of distensibility measurements taken during dilation to predict outcomes.

Assessment of annular distensibility in the aortic valve.

OBJECTIVES The recent introduction of transcatheter aortic heart valves into clinical practice has driven the need to develop methodologies to size such valves without access to the annulus in the manner hitherto possible with open heart surgery. To date, sizing has largely been done according to manufacturer-supplied guidelines based on transoesophageal echocardiography or multidetector computed tomography. We sought to examine how the diameter of the aortic valve annulus stretches under typical pressures encountered in normal and diseased states. In particular, we sought to measure how the area-derived diameter, Dcsa, i.e. the diameter derived from a cross-sectional area, varies with distending pressure. METHODS We conducted testing on 14 explanted pig hearts. Placing each heart in a 37 °C bath, an EndoFLIP EF-325 catheter (Crospon, Galway, Ireland) was introduced into the aortic valve transapically. The catheter allows intra-balloon pressure and up to 16 area-derived diameters to be measured simultaneously, thus permitting the shape of a lumen to be observed. By dividing the minimum area-derived diameter by distending pressure, a measure of distensibility (mm/mmHg) could be determined. Once the balloon was centred, balloon pressure was ramped between 100 and 200 mmHg, and the area-derived diameter was calculated at each pressure. RESULTS Between 100 and 200 mmHg, the mean (SD) increase in diameter was found to be 3.0 (1.5) mm. Distensibility in the different hearts ranged from 0 to 0.05 mm/mmHg. In some cases, the diameter change over the pressure range was negligible, whereas in one case, the diameter change over the range was 5 mm. Whereas different nominal values of diameter are to be expected, a significant variation in the degree of distensibility was observed. CONCLUSIONS Distensibility of the aortic valve annulus is highly variable. Measurement of this parameter in addition to nominal annulus diameter may suggest occasions where a larger transcatheter aortic-valve implantation valve than would be suggested by annulus diameter measurement alone, could be deployed safely with an objective of reducing regurgitation where the annulus is sufficiently distensible.

Microneedle-mediated transdermal bacteriophage delivery.

Interest in bacteriophages as therapeutic agents has recently been reawakened. Parenteral delivery is the most routinely-employed method of administration. However, injection of phages has numerous disadvantages, such as the requirement of a health professional for administration and the possibility of cross-contamination. Transdermal delivery offers one potential means of overcoming many of these problems. The present study utilized a novel poly (carbonate) (PC) hollow microneedle (MN) device for the transdermal delivery of Escherichia coli-specific T4 bacteriophages both in vitro and in vivo. MN successfully achieved bacteriophage delivery in vitro across dermatomed and full thickness skin. A concentration of 2.67 × 10(6)PFU/ml (plaque forming units per ml) was detected in the receiver compartment when delivered across dermatomed skin and 4.0 × 10(3)PFU/ml was detected in the receiver compartment when delivered across full thickness skin. An in vivo study resulted in 4.13 × 10(3)PFU/ml being detected in blood 30 min following initial MN-mediated phage administration. Clearance occurred rapidly, with phages being completely cleared from the systemic circulation within 24h, which was expected in the absence of infection. We have shown here that MN-mediated delivery allows successful systemic phage absorption. Accordingly, bacteriophage-based therapeutics may now have an alternative route for systemic delivery. Once fully-investigated, this could lead to more widespread investigation of these interesting therapeutic viruses.

Improved protocol for processing stented porcine coronary arteries for immunostaining.

Percutaneous coronary intervention has resulted in a paradigm shift in the treatment of coronary artery disease and myocardial infarction. However, neither bare-metal stents nor polymer-coated drug-eluting stents represent ideal therapies at this time due to the undesired in-stent stenosis or delayed thrombosis. Hence there is pressing clinical need for greater understanding of the cellular mechanisms involved. It is hoped that this in turn will provide insight into designing and developing the next generation of stents. Although immunohistochemistry and immunofluorescence are appropriate tools in understanding the molecular histology, performing these techniques on stented blood vessels is technically challenging because of poor permeability of antibodies into the stented blood vessels which are embedded in methacrylate-based resins and inadequate image resolution due to autofluorescence. Hence there is a need to develop techniques which can facilitate immunohistochemistry/immunofluorescence procedures on stented blood vessel cross-sections. In this study we describe an improved protocol for processing stented porcine coronary arteries for immunostaining with smooth muscle cell, endothelial cell, monocyte and macrophage markers. We first identified the optimal conditions for resin embedding of stented artery and cross sectioned the vessels using high speed precision wafering diamond blade. The sections were then ground using two levels of water sandpaper on a Metaserve 2000 grinder to achieve the desired thickness. For immunostaining, we developed a novel deplasticization protocol which favors optimal antibody permeabilization. Our protocol not only provides feasibility of improved immunostaining of stented artery sections but also results in high quality images.

Motivational factors influencing older adults diagnosed with knee osteoarthritis to join and maintain an exercise program.

In order to provide successful interventions to increase physical activity among inactive older adults, it is imperative to understand motivational factors influencing exercise. The authors present data from 191 (baseline) and 125 (12-month) community-dwelling men and women with mean ages of 68.71 (7.47) and 67.55 (7.55) years, respectively, from a strength-training trial. Approximately 53% had diagnosed knee osteoarthritis. Using a Likert scale, participants self-reported their degree of motivation from personal, social, and environmental factors. Using multivariate analyses, the authors evaluated demographic and clinical correlates of motivational factors to join and continue with exercise. The following results were reported: Knee osteoarthritis was positively related to motivation from an organized exercise opportunity and from efficacy/outcome expectations, and knee pain was positively related to motivation from social support and experience with the exercise task. Understanding these motivators might help in targeting recruitment efforts and interventions designed to increase physical activity in older adults with lower extremity arthritis.

Statistical Properties of a Procedure for Analyzing Pulse Voltammetric Data.

O'Dea et al. (1983, J. Phys. Chem. 97, 3911-3918) proposed an empirical procedure for obtaining estimates and confidence intervals for kinetic parameters in a model for pulse voltammetric data. Their goal was to find a procedure that would run in real time, not necessarily one that would have well-defined statistical properties. In this paper we investigate some of the statistical properties of their procedure. We show that their estimation method is equivalent to maximum likelihood estimation, and their confidence intervals, while related to likelihood ratio confidence regions, have a coverage probability that is not fixed and that is potentially quite large. We suggest modifications of their procedure that lead to more traditional confidence intervals. We examine the effect on their procedure of the presence of nuisance paramters. Finally we discuss the possibility of serially correlated errors.

Fitness levels of firefighter recruits before and after a supervised exercise training program.

Federal law prohibits pre-employment physical examination of firefighter recruits, but these workers must perform intense exercise in arduous environments. Components of physical fitness of rookie firefighters (n = 115; 104 men, mean +/- SD: age = 28.3 +/- 4.3 years; height = 1.76 +/- 0.07 m; weight = 83.2 +/- 13.9 kg; percent body fat = 17 +/- 8%) were measured upon being hired and following a 16-week exercise training program (1 h.d(-1), 3 d.wk(-1)) designed to improve physical fitness. Maximum aerobic capacity (VO2max) was estimated from submaximal cycle ergometry, body composition from skinfold tests, flexibility from a sit and reach test, strength by hand grip dynamometry, and muscle endurance by a push-up test. The results are as follows (*, p