Biomedical subjects
N de Jong
Publications and source records attributed to N de Jong.
Physical exercise or micronutrient supplementation for the wellbeing of the frail elderly? A randomised controlled trial.
OBJECTIVE: To examine the effects of 17 weeks of physical exercise and micronutrient supplementation on the psychological wellbeing of 139 independently living, frail, elderly subjects (inactive, body mass index < or =25 or experiencing weight loss). METHODS: Participants (mean (SD) age 78.5 (5.7)) were randomly assigned to: (a) comprehensive, moderate intensity, group exercise; (b) daily micronutrient enriched foods (25-100% recommended daily amount); (c) both; (d) neither. A social programme and identical regular foods were offered as attention control and placebo. RESULTS: At baseline, moderate to low but significant correlations were found between general wellbeing scores and physical fitness (r = 0.28), functional performance (r = 0.37), and blood concentrations of pyridoxine (r = 0.20), folate (r = 0.25), and vitamin D (r = 0.23) (all p values < or =0.02), but not with physical activity levels and other blood vitamin concentrations. General wellbeing score and self rated health were not responsive to 17 weeks of exercise or nutritional intervention. CONCLUSION: Psychological wellbeing in frail elderly people was not responsive to 17 weeks of intervention with exercise and/or micronutrient enriched foods. The moderate but significant correlations between wellbeing and physical fitness and several blood vitamin concentrations at baseline suggest that changes in wellbeing may occur after long term interventions.
Imaging methods for myocardial contrast echocardiography: what to expect in the near future.
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Usefulness of power Doppler contrast echocardiography to identify reperfusion after acute myocardial infarction.
Microvascular integrity, as seen by myocardial contrast echocardiography (MCE), assesses whether myocardium has been successfully reperfused after an acute myocardial infarction. Until now this has been demonstrated only with intracoronary injection of an ultrasound contrast agent. Power Doppler imaging is a recently developed myocardial contrast echocardiographic method that counts the contrast microbubbles destroyed by ultrasounds and displays this number in color. This study sought to evaluate whether power Doppler MCE is able to visualize myocardial reperfusion during intravenous contrast injection. Thirty patients were evaluated 2 days after their first myocardial infarction during intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA). Coronary artery angiography and single-photon emission computed tomography (SPECT) were used as reference techniques. A 16-segment left ventricular model was used to relate perfusion to coronary artery territories. Sensitivity and specificity of power Doppler MCE for segments supplied by infarct-related arteries were 82% and 95%, respectively. Accuracy of power Doppler MCE and SPECT were similar (90% vs 92% on segmental basis and 98% vs 98% on coronary artery territory basis). Two-dimensional echocardiography was repeated after 6 weeks. Segments recovering wall motion after 6 weeks were defined as stunning myocardium. Dysfunctional but perfused myocardium at day 2 after the infarction showed a better late recovery of wall motion compared with dysfunctional but nonperfused myocardium (p <0.001). In conclusion, harmonic power Doppler imaging is a sensitive and specific method for the identification of myocardial reperfusion early after myocardial infarction. It yields prognostic information for late recovery of ventricular function differentiating stunning (dysfunctional but perfused) from necrotic myocardium (dysfunctional and nonperfused).
New technique for emboli detection and discrimination based on nonlinear characteristics of gas bubbles.
Detection and characterization of emboli in the blood stream is of high clinical importance for making decisions after surgery. In this study, a new technique based on the nonlinear oscillations of gas bubbles was applied to gaseous emboli detection, characterization and sizing. To simulate gaseous emboli, an experimental system was developed to produce air bubbles of uniform diameters ranging from 19 microm up to 200 microm. The ultrasonic setup consisted of low-frequency transducers operating at 130 kHz and 250 kHz and using low acoustic pressures (30 kPa and 55 kPa). The experimental and theoretical results show that, depending on the transmitted frequency and the bubble sizes, higher harmonic components were produced in the frequency spectrum of the backscattered echo. Nonresonating bubbles scatter either linearly when their sizes are far away from the resonance size or nonlinearly at the second or third harmonic frequency when their sizes are getting close to the resonance size. Only resonant bubbles or bubbles very close to the resonance size are able to scatter at higher harmonic frequencies (fourth and fifth). This property is used to discriminate resonating bubbles from other bubble sizes. The appearance of harmonic component in the frequency spectrum seems to be an unambiguous tool to differentiate gaseous emboli from solid emboli that scatter linearly.
Physical exercise and/or enriched foods for functional improvement in frail, independently living elderly: a randomized controlled trial.
OBJECTIVE: To examine the effects of an exercise program and an enriched food regimen on physical functioning of frail elderly persons. DESIGN: A 17-week randomized, placebo-controlled trial. SETTING: Community. PARTICIPANTS: One hundred fifty-seven independently living frail elderly (mean age, 78.7 +/- 5.6yr). INTERVENTION: Thirty-nine subjects participated in a twice weekly group exercise designed to improve daily functioning; 39 subjects daily ate foods enriched with vitamins and minerals (at 25%-100% of the recommended daily allowances); 42 subjects exercised and ate enriched foods; and 37 subjects served as controls. Nonexercising groups followed a social program; nonsupplement groups received the same food products without the micronutrients. MAIN OUTCOME MEASURES: Functional performance based on 6 performance tests, physical fitness based on 7 fitness tests, and disabilities based on the self-reported ability to perform 16 daily activities. RESULTS: Performance sum scores were significantly enhanced in trained (+8%) compared with nontrained subjects (-8%) (difference in change: 1.9 points, p < .001, adjusted for baseline scores). Fitness sum scores were significantly enhanced as well (+3% in trained vs -2% in nontrained) (difference in change: 0.9 points, p = .05, adjusted for baseline scores). No exercise effects on the disability score were observed. Consumption of enriched products did not affect performance, fitness, or disability scores. CONCLUSION: Our comprehensive exercise program, designed for widespread applicability, enhanced physical performance and fitness in a population of frail elderly. Daily consumption of micronutrient enriched foods showed no functional benefits within 17 weeks.
Nutrient-dense foods and exercise in frail elderly: effects on B vitamins, homocysteine, methylmalonic acid, and neuropsychological functioning.
BACKGROUND: Frail elders are at risk of suboptimal micronutrient status, functional decline, and neurologic disorders. The influence of oral multimicronutrients in physiologic doses and of moderately intense physical exercise on homocysteine (Hcy), methylmalonic acid (MMA), and neurologic functioning have not yet been investigated. OBJECTIVE: Our goal was to determine the effects of enriched foods and exercise on blood vitamins, Hcy, MMA, and neuropsychological functioning in the frail. DESIGN: A 17-wk randomized controlled intervention trial was used to study 1) enriched foods plus a social program, 2) regular foods plus exercise, 3) enriched foods plus exercise, and 4) regular foods plus a social program. Enriched foods contained multiple micronutrients (25-100% of the Dutch recommended dietary allowances); exercises focused on strength, coordination, flexibility, and endurance. Vitamin (cobalamin, red blood cell folate, and pyridoxal 5'-phosphate), Hcy, and MMA concentrations were measured and 2 neuropsychological tests were conducted. RESULTS: Vitamin concentrations were higher in the supplemented groups than in the unsupplemented groups (P < 0.001; total n = 130). Compared with baseline, cobalamin in the supplemented groups was increased by 22%, plasma folate by 101%, red blood cell folate by 87%, and pyridoxal 5'-phosphate by 68%. Concentrations in the unsupplemented groups changed by -2%, -6%, 1%, and -13%, respectively. Hcy decreased by 25% and MMA by 30% in the supplemented groups, compared with a small increase in Hcy (2%) and decrease in MMA (9%) in the unsupplemented groups. Exercise did not significantly affect vitamin, Hcy, or MMA concentrations. No significant effect of either intervention was observed on the neuropsychological tests. CONCLUSIONS: The decrease in Hcy and MMA in frail elders confirms a subclinical metabolic deficiency state. Enriched foods containing physiologic amounts of micronutrients have a beneficial effect on these metabolites. No effects of B vitamins on mental health were identified.
Selenium and zinc status are suboptimal in a sample of older New Zealand women in a community-based study.
The importance of selenium and zinc in the immune functioning of the aged is widely recognized. Seniors in New Zealand are at particularly high risk of low selenium status because of the low selenium soil environment. The zinc status of the New Zealand elderly has never been assessed. In this cross-sectional study, the biochemical selenium, zinc and lipid levels, physical functional capacity and dietary intakes of 103 randomly selected free-living New Zealand women (mean age +/- SD, 75 +/- 3 y) were assessed. Among nonusers of selenium supplements (n = 80), 80% [95% confidence interval (CI): 70; 88%] had plasma selenium levels (0.85 +/- 0.23 micromol/L) below 1.00 micromol/L [ approximately 10% below mean plasma selenium necessary for full expression of glutathione peroxidase (GPx) activity in New Zealand subjects]. Plasma selenium was strongly correlated with GPx: r = 0.56; P < 0.0001. For nonusers of zinc supplements (n = 88), serum zinc concentrations were 12.4 +/- 1.4 micromol/L, with 12% (95% CI: 6; 21%) having levels below the cut-off value (10.7 micromol/L). Estimated mean daily selenium and zinc intakes were 34 +/- 10 microg and 8.7 +/- 2.0 mg, respectively. Subjects in the highest tertile of a functional capacity index had higher biochemical zinc and selenium values than those in the lowest tertile (P < 0.05). The correlation between plasma selenium and GPx indicates that selenium intake in these women is still insufficient for full expression of GPx activity. Lower serum zinc levels also appear to be prevalent. Because a suboptimal trace element status may be more common among those with a poor physical functioning, promotion of the consumption of nutrient dense foods or supplements to improve selenium and zinc status of elderly women in New Zealand may be beneficial.
A new ultrasound contrast imaging approach based on the combination of multiple imaging pulses and a separate release burst.
A new ultrasound contrast imaging technique is described that optimally employs the rupture of the contrast agent. It is based on a combination of multiple high frequency, broadband, imaging pulses and a separate release burst. The imaging pulses are used to survey the target before and after the rupture and release of free gas bubbles. In this way, both processes (imaging and release) can be optimized separately. The presence of the contrast agent is simply detected by correlating or subtracting the signal responses of the imaging pulses. Because the time delay between the imaging pulses can be very short, the subtraction is less affected by tissue motion and can be done in real time. In vitro measurements showed that by using a release burst, the detection sensitivity increased 12 to 43 dB for different types of contrast agents. In the presence of a moving phantom, the increase in sensitivity was 22 dB. This new method is very sensitive for contrast agent detection in fundamental imaging mode and, therefore, non-linear propagation effects do not limit the maximum obtainable agent-to-tissue ratio. However, because of the inherent destruction of the contrast agent, it has to operate in an intermittent way. Through experiments, we have demonstrated the potential of the method to achieve simultaneous high sensitivity for contrast detection, i.e., high agent-to-tissue ratio, and high spatial resolution performance for different types of contrast agents.
Three-stage approach to ultrasound contrast detection.
A new method for detecting ultrasound contrast agents using a three-stage pulsing sequence is proposed. The method is based on observations showing that the scattering properties of contrast agents are modified by ultrasonic insonation at high power, but remain unchanged at low power. The objective of the first stage of the pulsing sequence is to use low power pulses to obtain a high resolution reference image without altering the agent. Higher power pulses in the second stage modify the contrast agent. The third stage detects the changes imposed to the contrast agent using low power pulses. A temporal filter is proposed to discriminate contrast response from clutter signal. The method is similar to power Doppler methods in that it uses several pulses to survey the target while destroying the agent. The new idea is to separate detection and destruction to circumvent a trade-off between sensitivity and resolution. Results from in vitro experiments with three different contrast agents are presented. The results are compared with harmonic power Doppler processed from the same data and show that an improvement in sensitivity is achievable by including the high power burst in the pulsing sequence. The results also show that the proposed filter reduces clutter artifacts from moving tissue.
Appraisal of 4 months' consumption of nutrient-dense foods within the daily feeding pattern of frail elderly.
OBJECTIVES: The appraisal and acceptance of micronutrient-dense versus identical regular foods among frail elderly are described. METHODS: Four types of dairy and four types of fruit products, either enriched with multiple micronutrients or not, were consumed by 150 frail elders for 4 months. In the first 2 and last 2 weeks of the intervention, hedonic aspects were assessed. Afterward, evaluation forms were completed. RESULTS: At the start, small but consistent differences existed between the enriched and the regular foods concerning the scores on pleasantness, desire to eat the product, and attitude toward the product. At the end, those ratings dropped slightly or stayed equal. Significant differences between groups emerged from the overall evaluation score: 6.4 plus or minus 1.6 and 7.7 plus or minus 1.7 respectively (p <.001). DISCUSSION: Optimization of the hedonic parameters of nutrient-dense foods and major long-term attention for application in the daily elderly feeding pattern is of essential importance.
Detection procedures of ultrasound contrast agents.
In the early days, it was believed that ultrasound contrast agents (UCA) could be sufficiently detected and imaged with the conventional imaging methods nowadays referred to as fundamental imaging. Newer imaging techniques proved to be more sensitive and are based on specific properties of the UCA. In general, these new characteristics involve non-linear and transient characteristics of contrast agents that appear at the high end of the diagnostic acoustic intensity. Imaging modalities used today for UCA are, besides fundamental imaging, second harmonic imaging, power Doppler, harmonic power Doppler, pulse inversion and pulse inversion Doppler, multi-pulse imaging and subharmonic imaging. Although the results of conventional second harmonic imaging are still not optimal for perfusion imaging applications, in combination with Doppler techniques (colour Doppler, power Doppler) it is one of the most sensitive techniques currently available in terms of agent-to-tissue ratio. Further improvements in current and future detection methods demand a complete understanding of the ultrasound-UCA interaction.
A fast rotating scanning unit for real-time three-dimensional echo data acquisition.
Most three-dimensional (3-D) echocardiography (3-DE) systems today are based on off-line methods where a large number of cross-sectional 2-D scans have to be acquired sequentially before a 3-D image can be reconstructed. Because acquisition is done step-by-step based on ECG triggering plus respiratory gating, this introduces motion artefacts and takes significant acquisition time. Another 3-D approach is based on 2-D transducers and parallel beam-forming. Such a system is very complex. In this manuscript, a fast continuously-rotating scanning unit, based on a 64-element phased-array transducer, is described. Typical rotation speed of the 3-D unit is 8 rotations per s. Therefore, 16 3-D volume datasets can be acquired per s in real-time. The first clinical examples as acquired with this probe are presented.
Ultrasound contrast imaging: current and new potential methods.
For 10 years, it was thought that ultrasound (US) contrast agents could be sufficiently detected and imaged with the conventional imaging techniques, now referred to as fundamental imaging. However, it turned out that fundamental imaging was not sensitive enough to detect the contrast agents in the presence of tissue. New imaging techniques that are based on specific properties of the contrast agents, such as nonlinear and transient scattering, proved to be more sensitive. US contrast imaging modalities used today are fundamental, second harmonic, harmonic power Doppler, and pulse inversion; new modalities, such as release burst and subharmonic imaging are emerging. Second harmonic imaging is still not optimal for perfusion imaging applications. However, in combination with Doppler techniques such as power Doppler, it is one of the most sensitive techniques currently available. A complete understanding of the US-contrast agent interaction is essential for further improvements of current detection methods, and the development of new imaging techniques.
Optical imaging of contrast agent microbubbles in an ultrasound field with a 100-MHz camera.
Ultrasound (US) contrast agents, used in the field of medical diagnosis, contain small microbubbles of a mean diameter of about 3 microm. The acoustic behavior of these bubbles in US field has been subject to many investigations. In this study, we propose a method to visualize the behavior of the bubbles in a 0.5-MHz US field under a microscope with a frame rate of 4 MHz. For low acoustic pressures (peak negative pressure of 0.12 MPa), the radius-time curve as measured from the optical images is in agreement with the theory. For higher acoustic pressures (peak negative pressure of 0.6 MPa), the recorded radius is significantly larger than predicted by theory and sudden change in the bubbles shapes has been noticed. The proposed method enables the study and characterization of individual bubbles and their encapsulation. It is expected that this will open new areas for quality control, US contrast imaging and US-guided drug delivery.
Effect of dietary supplements and physical exercise on sensory perception, appetite, dietary intake and body weight in frail elderly subjects.
This present study investigated the effect of a 17-week intervention programme with nutrient-dense foods (enriched with vitamins and minerals at 25-100% of the Dutch recommended dietary allowance) and/or physical exercise in 159 frail elderly subjects (forty-six men, 113 women, mean age 78.7 (SD 5.6) years). Subjects were randomized into four groups: (1) control, (2) nutrition intervention, (3) exercise or (4) both nutrition intervention and exercise. Main outcome variables were sensory perception (smell test and questionnaire), appetite (questionnaire), energy intake (3 d food record) and body weight (on a weighing scale and with dual energy X-ray absorptiometry measurements). At baseline, moderate but significant correlations were found between appetite and energy intake (r 0.30, P < 0.0001), between smell test and smell perception assessed by questionnaire (r 0.40, P < 0.0001) and between lean body weight and energy intake (r 0.50, P < 0.0001). Results after 17-weeks intervention revealed neither change in smell test scores (P = 0.19) nor in appetite (P = 0.17). A slight positive effect of exercise compared with non-exercising groups on energy intake (difference 0.5 MJ, P = 0.05) was shown next to a preserving effect of exercise on lean body mass (+0.08 kg) compared with a decrease (-0.4 kg) in non-exercisers (P < 0.02). The correlation between the change in lean body mass and change in energy intake was 0.18 (P = 0.05). In conclusion, an interesting preserving effect on lean body mass in frail elderly subjects due to 17 weeks of exercise was shown. Since a decline in lean body mass was observed in the non-exercisers, effects may be attributable to change in activity pattern. Changes in lean mass were also slightly, but significantly, correlated with changes in energy intake. In turn, energy intake was not related to a change in reported appetite or sensory perception. Nutrient-dense foods were not able to improve any of the outcome variables in this study.
Variability of micronutrient content in enriched dairy and fruit products. Executive Group for Development of Nutrient Dense Foods for Frail Elderly.
Accurate measures of micronutrient levels in newly developed enriched foods are indispensable for valid labelling, for determination of ultimate levels for possible claimed health effects and for safety. To date, only a limited amount of public literature is available on the reproducibility of laboratory analysis and on the similarity within novel fortified or enriched foods. Within the framework of an intervention trial in frail elderly, the micronutrient content of eight different types of enriched foods were repeatedly examined. The variance in concentrations of the vitamins B1, B2, B6, folic acid, B12, C, D, and E was studied, in addition to levels of the minerals zinc, iodine, calcium, iron and magnesium. Four main factors, possibly contributing to the variability of these micronutrient levels, were investigated: (1) type of product, (2) type of laboratory (between-laboratory) reproducibility), (3) time of the year (month) in which analyses were carried out (May-October) and (4) freshness of the product. The type of product and laboratory emerged as factors contributing mostly to the total variability in concentrations of vitamins (on average approximately 50% explained). However, none of the products consistently contained higher or lower levels compared to the other products and most target levels were met except for vitamin B2 in both dairy and fruit products and for folic acid and vitamin C in some fruit products. Differences between products were regarded as acceptable. Extensive evaluation of multiple lab results should be emphasised within the manufacturing process of enriched foods.
Immunity in frail elderly: a randomized controlled trial of exercise and enriched foods.
OBJECTIVE: To examine the effects of 17-wk physical exercise and enriched foods on cellular immune response (CIR) in frail elderly. METHODS: A total of 112 independently living, frail elderly men and women (mean age 79.2 +/- 5.9) received: twice weekly comprehensive, moderate intensity, progressive group exercise (group A, N = 26); daily enriched foods (group B, N = 31); both (group C, N = 29); or neither (group D, N = 26). Exercises focused on skills training. Foods were enriched with micronutrients with a high prevalence of deficiency in older people (at 25-100% the RDA). A social program and identical regular foods were offered as a control. CIR was measured by delayed-type hypersensitivity skin test response (DTH) against seven recall antigens expressed as the total number of positive responses and sum of diameters of all positive responses. RESULTS: No independent or interactive effect of enriched foods was observed. Therefore, exercise (groups A + C) was compared with no exercise (groups B + D). Nonexercising subjects showed an average decline of 0.5 responses compared with an unchanged responsiveness among exercising subjects (difference = 0.5, 95% CI: 0.04-0.89, P = 0.03 adjusted for baseline DTH, activity level, and micronutrient status). Nonexercising subjects had a larger decline in the sum of diameters of all positive responses than exercising subjects but the difference did not reach significance (adjusted difference = 2.1 mm, 95% CI:-1.0-4.8). CONCLUSION: Exercise may prevent or slow the age-related decline in immune response. Micronutrient enriched foods showed no effect. As infectious diseases can have debilitating or even fatal consequences for the elderly, prevention of the age-related decline in CIR could significantly improve their quality of life.