Value of real time three-dimensional echocardiography in patients with hypertrophic cardiomyopathy: Comparison with two-dimensional echocardiography and magnetic resonance imaging

Real time three-dimensional echocardiography (RT3DE) has been demonstrated to be an accurate technique to quantify left ventricular (LV) volumes and function in different patient populations. We sought to determine the value of RT3DE for evaluating patients with hypertrophic cardiomyopathy (HCM), in comparison with cardiac magnetic resonance imaging (MRI). Methods: We studied 20 consecutive patients with HCM who underwent two-dimensional echocardiography (2DE), RT3DE, and MRI. Parameters analyzed by echocardiography and MRI included: wall thickness, LV volumes, ejection fraction (LVEF), mass, geometric index, and dyssynchrony index. Statistical analysis was performed by Lin agreement coefficient, Pearson linear correlation and Bland-Altman model. Results: There was excellent agreement between 2DE and RT3DE (Rc = 0.92), 2DE and MRI (Rc = 0.85), and RT3DE and MRI (Rc = 0.90) for linear measurements. Agreement indexes for LV end-diastolic and end-systolic volumes were Rc = 0.91 and Rc = 0.91 between 2DE and RT3DE, Rc = 0.94 and Rc = 0.95 between RT3DE and MRI, and Rc = 0.89 and Rc = 0.88 between 2DE and MRI, respectively. Satisfactory agreement was observed between 2DE and RT3DE (Rc = 0.75), RT3DE and MRI (Rc = 0.83), and 2DE and MRI (Rc = 0.73) for determining LVEF, with a mild underestimation of LVEF by 2DE, and smaller variability between RT3DE and MRI. Regarding LV mass, excellent agreement was observed between RT3DE and MRI (Rc = 0.96), with bias of -6.3 g (limits of concordance = 42.22 to -54.73 g). Conclusion: In patients with HCM, RT3DE demonstrated superior performance than 2DE for the evaluation of myocardial hypertrophy, LV volumes, LVEF, and LV mass.

Three-dimensional model for multi-component reactive transport with variable density groundwater flow

PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport in variable density groundwater flow. Fluid density in PHWAT depends not on only the concentration of a single species as in SEAWAT, but also the concentrations of other dissolved chemicals that can be subject to reactive processes. Simulation results of PHWAT and PHREEQC-2 were compared in their predictions of effluent concentration from a column experiment. Both models produced identical results, showing that PHWAT has correctly coupled the sub-packages. PHWAT was then applied to the simulation of a tank experiment in which seawater intrusion was accompanied by cation exchange. The density dependence of the intrusion and the snow-plough effect in the breakthrough curves were reflected in the model simulations, which were in good agreement with the measured breakthrough data. Comparison simulations that, in turn, excluded density effects and reactions allowed us to quantify the marked effect of ignoring these processes. Next, we explored numerical issues involved in the practical application of PHWAT using the example of a dense plume flowing into a tank containing fresh water. It was shown that PHWAT could model physically unstable flow and that numerical instabilities were suppressed. Physical instability developed in the model in accordance with the increase of the modified Rayleigh number for density-dependent flow, in agreement with previous research. (c) 2004 Elsevier Ltd. All rights reserved.

Viral Load Predicts New World Health Organization Stage 3 and 4 Events in HIV-Infected Children Receiving Highly Active Antiretroviral Therapy, Independent of CD4 T Lymphocyte Value

Background. Many resource-limited countries rely on clinical and immunological monitoring without routine virological monitoring for human immunodeficiency virus (HIV)-infected children receiving highly active antiretroviral therapy (HAART). We assessed whether HIV load had independent predictive value in the presence of immunological and clinical data for the occurrence of new World Health Organization (WHO) stage 3 or 4 events (hereafter, WHO events) among HIV-infected children receiving HAART in Latin America. Methods. The NISDI (Eunice Kennedy Shriver National Institute of Child Health and Human Development International Site Development Initiative) Pediatric Protocol is an observational cohort study designed to describe HIV-related outcomes among infected children. Eligibility criteria for this analysis included perinatal infection, age ! 15 years, and continuous HAART for >= 6 months. Cox proportional hazards modeling was used to assess time to new WHO events as a function of immunological status, viral load, hemoglobin level, and potential confounding variables; laboratory tests repeated during the study were treated as time-varying predictors. Results. The mean duration of follow-up was 2.5 years; new WHO events occurred in 92 (15.8%) of 584 children. In proportional hazards modeling, most recent viral load 15000 copies/mL was associated with a nearly doubled risk of developing a WHO event (adjusted hazard ratio, 1.81; 95% confidence interval, 1.05-3.11; P = 033), even after adjustment for immunological status defined on the basis of CD4 T lymphocyte value, hemoglobin level, age, and body mass index. Conclusions. Routine virological monitoring using the WHO virological failure threshold of 5000 copies/mL adds independent predictive value to immunological and clinical assessments for identification of children receiving HAART who are at risk for significant HIV-related illness. To provide optimal care, periodic virological monitoring should be considered for all settings that provide HAART to children.

Superior discriminating value of ACTH-stimulated serum 21-deoxycortisol in identifying heterozygote carriers for 21-hydroxylase deficiency

P>Background Congenital adrenal hyperplasia caused by classic 21-hydroxylase deficiency (21OHD) is an autosomal recessive disorder with a high prevalence of asymptomatic heterozygote carriers (HTZ) in the general population, making case detection desirable by routine methodology. HTZ for classic and nonclassic (NC) forms have basal and ACTH-stimulated values of 17-hydroxyprogesterone (17OHP) that fail to discriminate them from the general population. 21-Deoxycortisol (21DF), an 11-hydroxylated derivative of 17OHP, is an alternative approach to identify 21OHD HTZ. Objective To determine the discriminating value of basal and ACTH-stimulated serum levels of 21DF in comparison with 17OHP in a population of HTZ for 21OHD (n = 60), as well as in NC patients (n = 16) and in genotypically normal control subjects (CS, n = 30), using fourth generation tandem mass spectrometry after HPLC separation (LC-MS/MS). Results Basal 21DF levels were not different between HTZ and CS, but stimulated values were increased in the former and virtually nonresponsive in CS. Only 17 center dot 7% of the ACTH-stimulated 21DF levels overlapped with CS, when compared to 46 center dot 8% for 17OHP. For 100% specificity, the sensitivities achieved for ACTH-stimulated 21DF, 17OHP and the quotient [(21DF + 17OHP)/F] were 82 center dot 3%, 53 center dot 2% and 87%, using cut-offs of 40, 300 ng/dl and 46 (unitless), respectively. Similar to 17OHP, ACTH-stimulated 21DF levels did not overlap between HTZ and NC patients. A positive and highly significant correlation (r = 0 center dot 846; P < 0 center dot 001) was observed between 21DF and 17OHP pairs of values from NC and HTZ. Conclusion This study confirms the superiority of ACTH-stimulated 21DF, when compared to 17OHP, both measured by LC-MS/MS, in identifying carriers for 21OHD. Serum 21DF is a useful tool in genetic counselling to screen carriers among relatives in families with affected subjects, giving support to molecular results.

New gene technologies and their potential value for sugarcane

An efficient system is now in place for improving diverse sugarcane cultivars by genetic transformation, that is, the insertion of useful new genes into single cells followed by the regeneration of genetically modified (transgenic) plants. The method has already been used to introduce genes for resistance to several major diseases, insect pests and a herbicide, Field testing has begun, and research is underway to identify other genes for increased environmental stress resistance, agronomic efficiency and yield of sucrose or other valuable products. Experience in other crops has shown that genetically improved varieties which provide genuine environmental and consumer benefits are welcomed by producers and consumers. Substantial research is still needed, but these new gene technologies will reshape the sugar industry and determine the international competitive efficiency of producers.

Risk attitude, planting conditions and the value of seasonal forecasts to a dryland wheat grower

The value of a seasonal forecasting system based on phases of the Southern Oscillation was estimated for a representative dryland wheat grower in the vicinity of Goondiwindi. In particular the effects on this estimate of risk attitude and planting conditions were examined. A recursive stochastic programming approach was used to identify the grower's utility-maximising action set in the event of each of the climate patterns over the period 1894-1991 recurring In the imminent season. The approach was repeated with and without use of the forecasts. The choices examined were, at planting, nitrogen application rate and cultivar and, later in the season, choices of proceeding with or abandoning each wheat activity, The value of the forecasting system was estimated as the maximum amount the grower could afford to pay for its use without expected utility being lowered relative to its non use.

Effect of the bilateral hip bone density measurement on clinical practice in elderly subjects

Objectives: The aim of this study was to determine whether the addition of the measurement of bilateral hip bone mineral density (BMD) has an impact on indications for osteoporosis (OP) treatment in community-dwelling elderly individuals, based on criteria from the National Osteoporosis Foundation (NOF). Methods: In total, 605 consecutive community-dwelling elderly individuals who were 65 years and older were evaluated. Dual energy X-ray absorptiometry was used to determine the lowest T-score in the lumbar spine + unilateral hip, the bilateral hips, and the lumbar spine + bilateral hips. Risk factors associated with the lowest T-score in these three conditions were applied to indicate treatment in accordance with NOF criteria. McNemar`s test was used to assess the difference of adding bilateral hip BMD measurements. Results: There was a significant difference in the frequency of pharmacological indication using NOF criteria together with the lowest T-score for the three tests (72.8% for lumbar spine + bilateral hips and 71.2% for lumbar spine + unilateral hip; p=0.002). A higher frequency of treatment indication was also observed for lumbar spine + unilateral hip (71.2%) compared to bilateral hips (61.1%) (p<0.001). The discrepancies in treatment appeared to be more evident in women when analyzed by gender distribution. Conclusion: Our finding supports the theory that evaluation of the bilateral hips with the lumbar spine seems to be more sensitive measure for identifying patients with an osteoporosis treatment indication. Furthermore, despite the well-known artifact in the lumbar spine, this site should not be excluded when determining the indication for OP treatment in elderly people. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Supersonic velocimetry in a shock tube using laser enhanced ionisation and planar laser induced fluorescence

A novel flow-tagging technique is presented which was employed to measure gas velocities in the free stream of a shock tube. This method is based on the laser spectroscopic techniques of Laser-Enhanced Ionisation (LEI) and Laser-Induced Fluorescence (LIF). The flow in the shock tube is seeded with small amounts of sodium, and LEI is used to produce a substantial depletion of neutral sodium atom concentration in a well-defined region of the flow, by using two wavelength-resonance excitation and subsequent collisional ionisation. At a specific time delay, single-laser-pulse planar LIF is utilised to produce a two-dimensional (2-D) inverse image of the depleted tagged region downstream of the flow. By measuring the displacement of the tagged region, free stream velocities in a shock tube were determined. Large variations in the concentration of sodium seeded into the flow were observed and even in the presence of these large variations accurate free-stream velocity measurements were obtained. The experimentally determined value for velocity compares very well with the predicted velocity.

Influence of estrogen deficiency and its treatment with alendronate and estrogen on bone density around osseointegrated implants: radiographic study in female rats

Objective. This study evaluated the influence of estrogen deficiency and its treatment on bone density around integrated implants. Study design. Implants were placed in female rat tibiae. The animals were assigned to 5 groups: control, sham, ovariectomy, estrogen, and alendronate. The control group was humanely killed to confirm integration of the implant. The others were submitted to ovariectomy or sham surgery. Bone density was measured by digital radiographs at 6 points on sides of the implant. Results. The analysis of radiographic bone density revealed estrogen privation had a negative impact only in the cancellous bone. The estrogen group differed significantly ( P <.05) from the ovariectomy and alendronate groups. The alendronate group presented the highest density for all evaluated regions. Conclusion. Ovariectomy caused a decrease in the radiographic bone density in the cancellous region. Estrogen replacement therapy and alendronate were effective treatments in preventing bone mass loss around integrated implants.

Bone mineral apparent density in juvenile dermatomyositis: the role of lean body mass and glucocorticoid use

Objective: To analyse bone mineral density (BMD) in juvenile dermatomyositis (JDM) and its possible association with body composition, disease activity, duration of disease, glucocorticoid (GC) use, and biochemical bone parameters, including osteoprotegerin (OPG) and receptor activator of nuclear factor B (RANKL). Methods: Twenty girls with JDM and 20 controls matched for gender and age were selected. Body composition and BMD were analysed by dual-energy X-ray absorptiometry (DXA) and bone mineral apparent density (BMAD) was calculated. Duration of disease, cumulative GC, and GC pulse therapy use were determined from medical records. Disease activity and muscle strength were measured by the Disease Activity Score (DAS), the Childhood Myositis Assessment Scale (CMAS), and the Manual Muscle Test (MMT). Inflammatory and bone metabolism parameters were also analysed. OPG and RANKL were measured in patients and controls using an enzyme-linked immunosorbent assay (ELISA). Results: A lower BMAD in the femoral neck (p< 0.001), total femur (p< 0.001), and whole body (p=0.005) was observed in JDM patients compared to controls. Body composition analysis showed a lower lean mass in JDM compared to controls (p=0.015), but no difference was observed with regard to fat mass. A trend of lower serum calcium was observed in JDM (p=0.05), whereas all other parameters analysed, including OPG and RANKL, were similar. Multiple linear regression analysis revealed that, in JDM, lean mass (p< 0.01) and GC pulse therapy use (p< 0.05) were independent factors for BMAD in the hip region. Conclusions: This study has identified low lean mass and GC pulse therapy use as the major factors for low hip BMAD in JDM patients.

Effect of Severe Dietary Magnesium Deficiency on Systemic Bone Density and Removal Torque of Osseointegrated Implants

Purpose This study evaluated the effect of severe magnesium (Mg) dietary deficiency on systemic bone density and biomechanical resistance of bone tissue to the removal torque of osseointegrated implants Materials and Methods The sample consisted of 45 rats, each received a titanium implant in their tibial metaphysis After 60 days, the animals were divided into three groups (n = 15) according to their dietary Mg the control group received the recommended content of Mg, group Mg1 received a 75% reduction in dietary Mg content, and group Mg2 was fed a diet with a 90% reduction in Mg con tent Animals were sacrificed 150 days after implant placement Serum concentrations of Mg were measured and the effect of Mg deficiency on systemic bone density was evaluated by densitometry of the lumbar vertebrae and femur Biomechanical characteristics were measured by resistance of the bone tissue to removal of the implants Results Lower Mg serum concentrations were found for the Mg1 and Mg2 groups, however, densitometric analysis and torque evaluations showed a statistically significant difference only in the Mg2 group (P < 05) There was a statistically significant difference in removal torque between the Mg2 group and the control group Conclusions This study showed that a severe deficiency of Mg decreased the systemic bone density and removal torque of osseointegrated implants INT J ORAL MAXILLOFAC IMPLANTS 2010 25 1125-1130

Synthetic nanoemulsion resembling a protein-free model of 7-ketocholesterol containing low density lipoprotein: In vitro and in vivo studies

7-ketocholesterol (7-KC) differs from cholesterol by a functional ketone group at C7. It is an oxygenated cholesterol derivative (oxysterol), commonly present in oxidized low-density lipoprotein (LDL). Oxysterols are generated and participate in several physiologic and pathophysiologic processes. For instance, the cytotoxic effects of oxidized LDL have been widely attributed to bioactive compounds like oxysterols. The toxicity is in part due to 7-KC. Here we aimed to demonstrate the possibility of incorporating 7-KC into the synthetic nanoemulsion LDE, which resembles LDL in composition and behavior. This would provide a suitable artificial particle resembling LDL to study 7-KC metabolism. We were able to incorporate 7-KC in several amounts into LDE. The incorporation was evaluated and confirmed by several methods, including gel filtration chromatography, using radiolabeled lipids. The incorporation did not change the main lipid composition characteristics of the new nanoparticle. Particle sizes were also evaluated and did not differ from LDE. In vivo studies were performed by injecting the nanoemulsion into mice. The plasma kinetics and the targeted organs were the same as described for LDE. Therefore, 7-KC-LDE maintains composition, size and some functional characteristics of LDE and could be used in experiments dealing with 7-ketocholesterol metabolism in lipoproteins.

Characterization of high density lipoprotein particles in familial apolipoprotein A-I deficiency

Our aim was to characterize HDL subspecies and fat-soluble vitamin levels in a kindred with familial apolipoprotein A-I (apoA-I) deficiency. Sequencing of the APOA1 gene revealed a nonsense mutation at codon 22, Q[22] X, with two documented homozygotes, eight heterozygotes, and two normal subjects in the kindred. Homozygotes presented markedly decreased HDL cholesterol levels, undetectable plasma apoA-1, tuboeruptive and planar xanthomas, mild corneal arcus and opacification, and severe premature coronary artery disease. In both homozygotes, analysis of HDL particles by two-dimensional gel electrophoresis revealed undetectable apoA-I, decreased amounts of small a-3 migrating apoA-II particles, and only modestly decreased normal amounts of slow a migrating apoA-IV- and apoE-containing HDL, while in the eight heterozygotes, there was loss of large alpha-1 HDL particles. There were no significant decreases in plasma fat-soluble vitamin levels noted in either homozygotes or heterozygotes compared with normal control subjects. Our data indicate that isolated apoA-I deficiency results in marked HDL deficiency with very low apoA-II alpha-3 HDL particles, modest reductions in the separate and distinct plasma apoA-IV and apoE HDL particles, tuboeruptive xanthomas, premature coronary atherosclerosis, and no evidence of fat malabsorption.

A methodology for current density calculations in high-frequency RF resonators

As nuclear magnetic resonance imaging and spectroscopy move inexorably toward higher field-strength magnets in search of improved signal-to-noise ratio, spectral resolution, and spatial resolution, the way in which radiofrequency (RF) probes are designed changes. At higher frequencies, resonant cavities become the favored RF ''coil'' type and may be built using streamline elements to reduce the inductance of the system. In modeling such systems, the quasi-static approach of assuming that current flows evenly in all conductor cross sections and that adjacent conductors do not affect each other becomes less reasonable. The proximity of RF conductors in resonators typically causes RF eddy currents to flow, whereby the current density in each rung is altered by the RF fields generated by nearby conductors. The proper understanding and prediction of how resonators will perform require a model of the current densities flowing in conducting sections, including all RF eddy current effects. Very few models of this type have been presented in the literature. This article presents an overview of one such model and of how it may be applied to a variety of resonators, both shielded and unshielded, circular, and elliptical, in cross section. Results are presented from a shielded head coil operating at 2 tesla. (C) 1997 John Wiley & Sons, Inc.

Prognostic value of left atrial volume in patients who underwent dobutamine stress echocardiography for known or suspected coronary artery disease

Background Left atrial volume indexed (LAVI) has been reported as a predictor of cardiovascular events. We sought to determine the prognostic value of LAVI for predicting the outcome of patients who underwent dobutamine stress echocardiography (DSE) for known or suspected coronary artery disease (CAD). Methods From January 2000 to July 2005, we studied 981 patients who underwent DSE and off-line measurements of LAVI. The value of DSE over clinical and LAVI data was examined using a stepwise log-rank test. Results During a median follow-up of 24 months, 56 (6%) events occurred. By univariate analysis, predictors of events were male sex, diabetes mellitus, previous myocardial infarction, left ventricular ejection fraction (LVEF), left atrial diameter indexed, LAVI, and abnormal DSE. By multivariate analysis, independent predictors were LVEF (relative risk [RR] = 0.98, 95% CI 0.95-1.00), LAVI (RR = 1.04, 95% CI 1.02-1.05), and abnormal DSE (RR = 2.70, 95% CI 1.28-5.69). In an incremental multivariate model, LAVI was additional to clinical data for predicting events (chi(2) 36.8, P < .001). The addition of DSE to clinical and LAVI yielded incremental information (chi(2) 55.3, P < .001). The 3-year event-free survival in patients with normal DSE and LAVI <= 33 mL/m(2) was 96%; with abnormal DSE and LAVI <= 33 mL/m(2), 91%; with normal DSE and LAVI >34 mL/m(2), 83%; and with abnormal DSE and LAVI >34 mL/m(2) 51%. Conclusion Left atrial volume indexed provides independent prognostic information in patients who underwent DSE for known or suspected CAD. Among patients with normal DSE, those with larger LAVI had worse outcome, and among patients with abnormal DSE, LAVI was still predictive. (Am Heart J 2008; 156:1110-6.)