Comparison of the 2010 and 2020 World Health Organization guidelines on physical activity in patients with percutaneous coronary interventions early after hospital discharge

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Swiss heart foundation

Background

Physical activity (PA) is inversely associated with mortality and adverse outcome in patients with cardiovascular disease, and can be objectively measured by accelerometry. In 2020, the World Health Organization (WHO) has updated their recommendations on PA for adults including those with chronic conditions, omitting the 10 min bout criterion.[1] The aim of this study was to determine the proportions of cardiac patients immediately after hospital discharge from percutaneous coronary interventions (PCI) who fulfil the old [2] and updated WHO PA criteria, and compare the results with established step-based cut-off values.

Methods

Patients after PCI for acute or chronic coronary syndrome with a maximal age of 80 and eligible for ambulatory cardiac rehabilitation were recruited for this observational single centre study. They were provided with a wrist-worn tri-axial accelerometer without display that recorded movement data starting from the day following hospital discharge for the subsequent 18 days. Acceleration data was analysed with the widely used free GGIR package. The proportions of patients fulfilling recommendations for moderate to vigorous PA (MVPA) were determined according to the 2010 and 2020 WHO guidelines as well as 7,500 [3] and 10,000 steps.[4]

Results

159 patients (41%) participated in this study. Data from 135 patients (85%), who had at least 7 days of ≥12 h wear-time were included in the analyses. Their median age was 62 (1st quartile 56, 3rd quartile 68), 22 (16%) were women, and 15 and 120 patients had a CCS and ACS, respectively. Their median wear time was 18 (16, 18) days. 102 (75.6%) had at least 30 min of MVPA on an average day and hence fulfilled the 2020 WHO guidelines. When MVPA was determined using the 2010 WHO guidelines, which only counted MVPA of bouts of at least 10 min, only 23 patients (17.8%) achieved at least 30 min of MVPA on an average day (Figure 1). 67.4% of our patients achieved ≥7,500 steps/d and 71 patients (52.6%) performed ≥10,000 steps/d.

Conclusion

In cardiac patients early after PCI most of the MVPA was accumulated in bouts shorter than 10 min. Applying the 2010 and 2020 WHO PA criteria to objectively measured PA led to a fourfold discrepancy. The 7,500 step cut-off corresponded with the 2020 WHO recommendations. Since achievement of intensity- or step-based cut-offs is greatly dependent on device type, wearing location, data sampling and analysis, it is currently poorly defined and not suited for patient classification and counselling. The clinical implication of this observation will be assessed in a cardiovascular outcome analysis.

Hyperspectral Nanoimaging of van der Waals Polaritonic Crystals

Phonon polaritons (PhPs) in van der Waals (vdW) crystal slabs enable nanoscale infrared light manipulation. Specifically, periodically structured vdW slabs behave as polaritonic crystals (vdW-PCs), where the polaritons form Bloch modes. Because the polariton wavelengths are smaller than that of light, conventional far-field spectroscopy does not allow for a complete characterization of vdW-PCs or for revealing their band structure. Here, we perform hyperspectral infrared nanoimaging and analysis of PhPs in a vdW-PC slab made of h-BN. We demonstrate that infrared spectra recorded at individual spatial positions within the unit cell of the vdW-PC can be associated with its band structure and local density of photonic states (LDOS). We thus introduce hyperspectral infrared nanoimaging as a tool for the comprehensive analysis of polaritonic crystals, which could find applications in the reconstruction of complex polaritonic dispersion surfaces in momentum-frequency space or for exploring exotic electromagnetic modes in topological photonic structures.

Deeply subwavelength phonon-polaritonic crystal made of a van der Waals material

Photonic crystals (PCs) are periodically patterned dielectrics providing opportunities to shape and slow down the light for processing of optical signals, lasing and spontaneous emission control. Unit cells of conventional PCs are comparable to the wavelength of light and are not suitable for subwavelength scale applications. We engineer a nanoscale hole array in a van der Waals material (h-BN) supporting ultra-confined phonon polaritons (PhPs)-atomic lattice vibrations coupled to electromagnetic fields. Such a hole array represents a polaritonic crystal for mid-infrared frequencies having a unit cell volume of [Formula: see text] (with λ0 being the free-space wavelength), where PhPs form ultra-confined Bloch modes with a remarkably flat dispersion band. The latter leads to both angle- and polarization-independent sharp Bragg resonances, as verified by far-field spectroscopy and near-field optical microscopy. Our findings could lead to novel miniaturized angle- and polarization-independent infrared narrow-band couplers, absorbers and thermal emitters based on van der Waals materials and other thin polar materials.

Factors associated with uninvestigated dyspepsia in students at 4 Latin American schools of medicine: A multicenter study

INTRODUCTION AND AIMS

Dyspepsia is a multifactorial disease that can involve alcohol, tobacco, or nonsteroidal anti-inflammatory drug use, as well as lifestyle, diet, socioeconomic elements, or psychologic factors. The aim of the present article was to establish the frequency of uninvestigated dyspepsia and determine its associated factors in students at 4 Latin American schools of medicine.

MATERIALS AND METHODS

A cross-sectional, analytic study was conducted, in which a survey made up of closed-ended questions was applied at just one point in time. The association between the variables was then analyzed. A new questionnaire for the diagnosis of dyspepsia was one of the tests utilized to diagnose uninvestigated dyspepsia. Generalized linear models were used for the bivariate and multivariate analyses, employing the Poisson model with the log link function, obtaining crude prevalence ratios, adjusted prevalence ratios, and their 95% confidence intervals.

RESULTS

Of the 1,241 individuals surveyed, 54% (841) were females and the median age was 21 years (range: 19-23 years). Prevalence of uninvestigated dyspepsia was 46%. The factors that had a direct association with dyspepsia were: depression, difficulty sleeping, and coffee consumption. On the contrary, eating regularly in a boarding house and the male sex had an inverse association.

CONCLUSIONS

Uninvestigated dyspepsia frequency was high in students at 4 Latin American schools. Depression, difficulty sleeping, and steady coffee drinking were factors directly associated with dyspepsia, whereas male sex and eating out at regular hours were factors with a reverse association. Therefore, we recommend that universities implement early detection programs for this highly preventable pathology.

The impact of cardiovascular co-morbidities and duration of diabetes on the association between microvascular function and glycaemic control

BACKGROUND

Good glycaemic control in type 2 diabetes (T2DM) protects the microcirculation. Current guidelines suggest glycaemic targets be relaxed in advanced diabetes. We explored whether disease duration or pre-existing macrovascular complications attenuated the association between hyperglycaemia and microvascular function.

METHODS

743 participants with T2DM (n = 222), cardiovascular disease (CVD = 183), both (n = 177) or neither (controls = 161) from two centres in the UK, underwent standard clinical measures and endothelial dependent (ACh) and independent (SNP) microvascular function assessment using laser Doppler imaging.

RESULTS

People with T2DM and CVD had attenuated ACh and SNP responses compared to controls. This was additive in those with both (ANOVA p < 0.001). In regression models, cardiovascular risk factors accounted for attenuated ACh and SNP responses in CVD, whereas HbA₁c accounted for the effects of T2DM. HbA₁c was associated with ACh and SNP response after adjustment for cardiovascular risk factors (adjusted standardised beta (β) -0.096, p = <0.008 and -0.135, p < 0.001, respectively). Pre-existing CVD did not modify this association (β -0.099; p = 0.006 and -0.138; p < 0.001, respectively). Duration of diabetes accounted for the association between HbA₁c and ACh (β -0.043; p = 0.3), but not between HbA₁c and SNP (β -0.105; p = 0.02).

CONCLUSIONS

In those with T2DM and CVD, good glycaemic control is still associated with better microvascular function, whereas in those with prolonged disease this association is lost. This suggests duration of diabetes may be a better surrogate for "advanced disease" than concomitant CVD, although this requires prospective validation.

Nanoimaging of resonating hyperbolic polaritons in linear boron nitride antennas

Polaritons in layered materials-including van der Waals materials-exhibit hyperbolic dispersion and strong field confinement, which makes them highly attractive for applications including optical nanofocusing, sensing and control of spontaneous emission. Here we report a near-field study of polaritonic Fabry-Perot resonances in linear antennas made of a hyperbolic material. Specifically, we study hyperbolic phonon-polaritons in rectangular waveguide antennas made of hexagonal boron nitride (h-BN, a prototypical van der Waals crystal). Infrared nanospectroscopy and nanoimaging experiments reveal sharp resonances with large quality factors around 100, exhibiting atypical modal near-field patterns that have no analogue in conventional linear antennas. By performing a detailed mode analysis, we can assign the antenna resonances to a single waveguide mode originating from the hybridization of hyperbolic surface phonon-polaritons (Dyakonov polaritons) that propagate along the edges of the h-BN waveguide. Our work establishes the basis for the understanding and design of linear waveguides, resonators, sensors and metasurface elements based on hyperbolic materials and metamaterials.

Optical Nanoimaging of Hyperbolic Surface Polaritons at the Edges of van der Waals Materials

Hyperbolic polaritons in van der Waals (vdW) materials recently attract a lot of attention, owing to their strong electromagnetic field confinement, ultraslow group velocities, and long lifetimes. Typically, volume-confined hyperbolic polaritons (HPs) are studied. Here we show the first near-field optical images of hyperbolic surface polaritons (HSPs), which are confined and guided at the edges of thin flakes of a vdW material. To that end, we applied scattering-type scanning near-field optical microscopy (s-SNOM) for launching and real-space nanoimaging of hyperbolic surface phonon polariton modes on a hexagonal boron nitride (h-BN) flake. Our imaging data reveal that the fundamental HSP mode exhibits a stronger field confinement (shorter wavelength), smaller group velocities, and nearly identical lifetimes, as compared to the fundamental HP mode of the same h-BN flake. Our experimental data, corroborated by theory, establish a solid basis for future studies and applications of HPs and HSPs in vdW materials.

Spin doping using transition metal phthalocyanine molecules

Molecular spins have become key enablers for exploring magnetic interactions, quantum information processes and many-body effects in metals. Metal-organic molecules, in particular, let the spin state of the core metal ion to be modified according to its organic environment, allowing localized magnetic moments to emerge as functional entities with radically different properties from its simple atomic counterparts. Here, using and preserving the integrity of transition metal phthalocyanine high-spin complexes, we demonstrate the magnetic doping of gold thin films, effectively creating a new ground state. We demonstrate it by electrical transport measurements that are sensitive to the scattering of itinerant electrons with magnetic impurities, such as Kondo effect and weak antilocalization. Our work expands in a simple and powerful way the classes of materials that can be used as magnetic dopants, opening a new channel to couple the wide range of molecular properties with spin phenomena at a functional scale.

Measures of atherosclerotic burden are associated with clinically manifest cardiovascular disease in type 2 diabetes: a European cross-sectional study

BACKGROUND

There is a need to develop and validate surrogate markers of cardiovascular disease (CVD) in subjects with diabetes. The macrovascular changes associated with diabetes include aggravated atherosclerosis, increased arterial stiffness and endothelial dysfunction. The aim of this study was to determine which of these factors is most strongly associated with clinically manifest cardiovascular events.

METHODS

Vascular changes were measured in a cohort of 458 subjects with type 2 diabetes (T2D) and CVD (myocardial infarction, stroke or lower extremity arterial disease), 527 subjects with T2D but without clinically manifest CVD and 515 subjects without T2D and with or without CVD.

RESULTS

Carotid intima-media thickness (IMT) and ankle-brachial pressure index were independently associated with the presence of CVD in subjects with T2D, whereas pulse wave velocity and endothelial function provided limited independent additive information. Measurement of IMT in the carotid bulb provided better discrimination of the presence of CVD in subjects with T2D than measurement of IMT in the common carotid artery. The factors most significantly associated with increased carotid IMT in T2D were age, disease duration, systolic blood pressure, impaired renal function and increased arterial stiffness, whereas there were no or weak independent associations with metabolic factors and endothelial dysfunction.

CONCLUSIONS

Measures of atherosclerotic burden are associated with clinically manifest CVD in subjects with T2D. In addition, vascular changes that are not directly related to known metabolic risk factors are important in the development of both atherosclerosis and CVD in T2D. A better understanding of the mechanisms involved is crucial for enabling better identification of CVD risk in T2D.

Embedded purification for electron beam induced Pt deposition using MeCpPtMe3

Two different room-temperature processes for the electron beam induced deposition of high purity platinum (Pt), using the standard MeCpPtMe3 precursor and oxygen for purification, have been investigated. The first process is a sequential method, which uses two independent gas injector systems (GIS) in order to perform a standard Pt deposition, followed by an e-beam post-irradiation under oxygen flux. The second process is a parallel, single-step process that includes a simultaneous flow of both precursor and oxygen, using an add-on device that can be mounted on the standard GIS needle. Both processes are effective in producing high purity Pt depositions close to 100 at%. The first method requires a high current and irradiation dose in the clean-up phase, and provides Pt structures with small voids, a maximum thickness of around 100 nm and resistivity of 88 ± 10 μΩ cm. The second method requires a high oxygen/precursor flux ratio and produces void-free structures with resistivity of 60 ± 5 μΩ cm, only six times the bulk value for Pt. The second method is easier to use and produces a void-free deposition of high purity Pt.

Controlling graphene plasmons with resonant metal antennas and spatial conductivity patterns

Graphene plasmons promise unique possibilities for controlling light in nanoscale devices and for merging optics with electronics. We developed a versatile platform technology based on resonant optical antennas and conductivity patterns for launching and control of propagating graphene plasmons, an essential step for the development of graphene plasmonic circuits. We launched and focused infrared graphene plasmons with geometrically tailored antennas and observed how they refracted when passing through a two-dimensional conductivity pattern, here a prism-shaped bilayer. To that end, we directly mapped the graphene plasmon wavefronts by means of an imaging method that will be useful in testing future design concepts for nanoscale graphene plasmonic circuits and devices.

Experimental verification of the spectral shift between near- and far-field peak intensities of plasmonic infrared nanoantennas

Theory predicts a distinct spectral shift between the near- and far-field optical response of plasmonic antennas. Here we combine near-field optical microscopy and far-field spectroscopy of individual infrared-resonant nanoantennas to verify experimentally this spectral shift. Numerical calculations corroborate our experimental results. We furthermore discuss the implications of this effect in surface-enhanced infrared spectroscopy.

Highly stable and finely tuned magnetic fields generated by permanent magnet assemblies

Permanent magnetic materials are the only magnetic source that can be used to generate magnetic fields without power consumption or maintenance. Such stand-alone magnets are very attractive for many scientific and engineering areas, but they suffer from poor temporal field stability, which arises from the strong sensitivity of the magnetic materials and mechanical support to temperature variation. In this work, we describe a highly efficient method useful to cancel the temperature coefficient of permanent magnet assemblies in a passive and accurate way. It is based on the combination of at least two units made of magnetic materials with different temperature coefficients arranged in such a way that the ratio of the fields generated by each unit matches the ratio of their effective temperature coefficients defined by both the magnetic and mechanical contributions. Although typically available magnetic materials have negative temperature coefficients, the cancellation is achieved by aligning the fields generated by each unit in the opposite direction. We demonstrate the performance of this approach by stabilizing the field generated by a dipolar Halbach magnet, recently proposed to achieve high field homogeneity. Both the field drift and the homogeneity are monitored via nuclear magnetic resonance spectroscopy experiments. The results demonstrate the compatibility of the thermal compensation approach with existing strategies useful to fine-tune the spatial dependence of the field generated by permanent magnet arrays.

Resolving the electromagnetic mechanism of surface-enhanced light scattering at single hot spots

Light scattering at nanoparticles and molecules can be dramatically enhanced in the 'hot spots' of optical antennas, where the incident light is highly concentrated. Although this effect is widely applied in surface-enhanced optical sensing, spectroscopy and microscopy, the underlying electromagnetic mechanism of the signal enhancement is challenging to trace experimentally. Here we study elastically scattered light from an individual object located in the well-defined hot spot of single antennas, as a new approach to resolve the role of the antenna in the scattering process. We provide experimental evidence that the intensity elastically scattered off the object scales with the fourth power of the local field enhancement provided by the antenna, and that the underlying electromagnetic mechanism is identical to the one commonly accepted in surface-enhanced Raman scattering. We also measure the phase shift of the scattered light, which provides a novel and unambiguous fingerprint of surface-enhanced light scattering.

Light scattering from nanoscale objects can be dramatically enhanced in the proximity of optical antennas. Here, by studying the amplitude and phase of the light scattered from a tip located at the hot spot of an antenna, the underlying electromagnetic mechanism of this enhancement is resolved.

Stromelysin-1 polymorphism as a new potential risk factor in progression of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive lung disease (COPD) is characterised by partially reversible usually progressive airflow limitation caused by inflammation and remodelling. Stromelysin-1 (MMP-3) has regulatory activity on other matrix-metalloproteinases. Altered MMP-3 activity has been described in different diseases. We investigated the role of a promoter MMP-3 polymorphism in determining susceptibility and severity of COPD.

METHODS

We studied 147 patients with COPD in stable conditions and distinguished two groups based on FEV1 values. In 100 patients functional modifications across a two-year period were noted. 133 healthy subjects were used as controls. Genotyping for the -1171 5A/6A MMP-3 polymorphism was performed using nucleotide sequencing.

RESULTS

No difference was noted in the genotype distribution between COPD patients and controls. However, among patients with severe disease 6A/6A genotype and 6A allelic frequency were significantly more represented than among mild-moderate patients (p < 0.05). The 6A/6A genotype was also associated with a higher FEV1 decline over time.

CONCLUSIONS

Our data suggests that -1171 6A allele does not represent a risk factor for the development of COPD while it is associated with more severe disease and different functional decline. We hypothesis that a disregulation of MMP-3, possibly caused by the -1171 5A/6A polymorphism or other linked variants, may lead to different progression in COPD.

Surface UV aging of elastomers investigated with microscopic resolution by single-sided NMR

Depth profiles taken from the surface of UV irradiated natural rubber sheets have been measured with microscopic resolution using a Profile NMR-MOUSE. An NMR observable related to the sum of the spin echoes in the Carr-Purcell-Meiboom-Gill pulse sequence was used to characterize the cross-link density changes produced by the action of UV radiation in each sheet. The aging process was investigated as function of irradiation time and penetration depth. An exponential attenuation law with a space dependent absorption coefficient describes the change in the NMR observable with penetration depth. An Avrami model is used to describe the dependence of the absorption coefficient on the aging time. The method can be applied to investigate the effect of various aging agents on the surfaces of elastomers.

Multiecho sequence for velocity imaging in inhomogeneous rf fields

The unambiguous determination of velocities with spatial resolution in a multiecho PFG NMR sequence strongly depends on the homogeneity of the B1 field. This affects, in particular, the use of surface coils that bear considerable potential for on-line flow monitoring where a fast-imaging sequence can become vital. However, even with most rf coils dedicated for imaging applications, B1 inhomogeneities are sufficiently large to generate severe problems in performing velocity-imaging experiments. In this paper, the use of a combination of different phase cycles in Carr-Purcell sequences is discussed. The suggested phase cycling scheme tolerates large flip angle imperfections arising in inhomogeneous B1 fields, and thus allows acquisition of a maximum number of echoes within a pulse train. The performance of the velocity-imaging sequence is proven by using phantom samples developing known laminar flow patterns.

Single-sided sensor for high-resolution NMR spectroscopy

The unavoidable spatial inhomogeneity of the static magnetic field generated by open sensors has precluded their use for high-resolution NMR spectroscopy. In fact, this application was deemed impossible because these field variations are usually orders of magnitude larger than those created by the microscopic structure of the molecules to be detected. Recently, chemical shift resolved NMR spectra were observed for the first time outside a portable single-sided magnet by implementing a method that exploits inhomogeneities in the rf field designed to reproduce variations of the static magnetic field. In this communication, we describe in detail the magnet system built from permanent magnets as well as the rf coil geometry used to compensate the static field variations.

Self-diffusion measurements by a mobile single-sided NMR sensor with improved magnetic field gradient

A simple and fast method of measuring self-diffusion coefficients of protonated systems with a mobile single-sided NMR sensor is discussed. The NMR sensor uses a magnet geometry that generates a highly flat sensitive volume where a strong and highly uniform static magnetic field gradient is defined. Self-diffusion coefficients were measured by Hahn- and stimulated echoes detected in the presence of the uniform magnetic field gradient of the static field. To improve the sensitivity of these experiments, a Carr-Purcell-Meiboom-Gill pulse sequence was applied after the main diffusion-encoding period. By adding the echo train the experimental time was strongly shortened, allowing the measurement of complete diffusion curves in less than 1min. This method has been tested by measuring the self-diffusion coefficients D of various organic solvents and poly(dimethylsiloxane) samples with different molar masses. Diffusion coefficients were also measured for n-hexane absorbed at saturation in natural rubber with different cross-link densities. The results show a dependence on the concentration that is in good agreement with the theoretical prediction. Moreover, the stimulated-echo sequence was successfully used to measure the diffusion coefficient as a function of the evolution time in systems with restricted diffusion. This type of experiment proves the pore geometry and gives access to the surface-to-volume ratio. It was applied to measure the diffusion of water in sandstones and sheep Achilles tendon. Thanks to the strong static gradient G(0), all diffusion coefficients could be measured without having to account for relaxation during the pulse sequence.

Preliminary evidence for cachexia in patients with well-established ankylosing spondylitis

OBJECTIVES

Cachexia, defined as an accelerated loss of skeletal muscle in the context of a chronic inflammatory response, is common in rheumatoid arthritis but it has not been demonstrated in patients with ankylosing spondylitis (AS). The aim of this study was to determine muscle wasting and its functional consequences in a group of patients with well-established AS.

METHODS

Nineteen male patients (mean age 53 yrs) with long-standing AS (mean disease duration 19 yrs) and radiological changes (84% had one or more syndesmophytes) were compared with 19 age-matched healthy males with similar levels of habitual physical activity. Body composition was assessed by dual energy X-ray absorptiometry. Muscle strength was measured by isokinetic knee extension and hand grip dynamometry, and by 30 s arm curl and chair sit-to-stand tests.

RESULTS

AS patients showed a statistically and clinically significant 12% reduction in arms and legs lean mass, a proxy measure of total body skeletal muscle mass, compared with healthy controls (P < 0.05). This muscle loss was significantly associated with reduced upper and lower body strength (correlation coefficients ranging between 0.37 and 0.79, P < 0.05).

CONCLUSION

These results provide preliminary evidence that cachexia is a functionally relevant systemic complication of AS, particularly in patients with long-standing disease and radiological changes. Progressive resistance training and other interventions aimed at stimulating skeletal muscle growth might be beneficial in this population, and further studies on the pathophysiology of cachexia in AS patients are needed.

Profiles with microscopic resolution by single-sided NMR

A single-sided NMR sensor to produce depth profiles with microscopic spatial resolution is presented. It uses a novel permanent magnet geometry that generates a highly flat sensitive volume parallel to the scanner surface. By repositioning the sensitive slice across the object one-dimensional profiles of the sample structure can be produced with a space resolution better than 5 microm. The open geometry of the sensor results in a powerful testing tool to characterize arbitrarily sized objects in a non-destructive way.

Cardiovascular responses to aerobic step dance sessions with and without appendicular overload

AIM

Several studies showed that exercise intensity during aerobic step dance can be modified varying stepping rate, bench height and manipulating body mass using hand held or adding loads to the torso. The aim of this study was to determine the cardiovascular responses during aerobic step dance using an overload strategy not yet investigated: appendicular overload.

METHODS

Ten healthy and moderately trained women (mean+/-SD: age 27+/-3.4 years, height 167.8+/-4.6 cm, body mass 55.7+/-4.7 kg, body mass index 19.8+/-1.6, VO2max44.4+/-6.1 mLxkg-1xmin-1) performed an incremental treadmill test to determine VO2peak, the VO2-heart rate (HR) and rating of perceived exertion (RPE)-HR relationships. Within 1 week from the laboratory test, the subjects performed two identical aerobic step dance routines: one using a track suit with loads placed in pockets close to the legs and arms and another without overload.

RESULTS

The appendicular overload (10% of body mass) significantly increased the exercise intensity from 84.5% to 89.8% of HRmax corresponding to 68.9% and 78.3% of VO2peak, respectively (P<0.01). Similarly, RPE increased from 12.1 to 15.7 (P<0.001). The estimated VO2 and the caloric expenditure rose from 30.3 to 34.7 mLxkg-1xmin-1 and from 251 to 288 kcal, respectively.

CONCLUSION

This study shows that the use of appendicular overload significantly increases the energy cost of aerobic step session similarly to other overload strategies already reported in the literature.

Velocity imaging by ex situ NMR

A pulsed field gradient stimulated spin-echo NMR sequence is combined with imaging methods to spatially resolve velocity distributions and to measure 2D velocity maps ex situ. The implementation of these techniques in open sensors provides a powerful non-invasive tool to measure molecular displacement in a large number of applications inaccessible to conventional closed magnets. The method is implemented on an open tomograph that provides 3D spatial localization by combining slice selection in the presence of a uniform static magnetic field gradient along the depth direction with pulsed field gradients along the two lateral directions. Different pipe geometries are used to demonstrate that the sequence performs well even in the extremely inhomogeneous B0 and B1 fields of these sensors.

Effect of inhaled combination therapy on asthma management

The growing use of guidelines to manage asthmatic patients prompted us to evaluate their impact on clinical practice. This study was performed in two similar groups of asthmatic patients. A retrospective and prospective review of medical records in an asthmatic population was performed. The patients were followed up for a mean period of 2 years before (group 1 [G1]) and after the publication of the Guideline for Asthma Treatment (group 2 [G2]). After evaluation of objective/clinical measurements we noticed a significant difference between both groups. There were 23 and 40 patients who did not complain of any respiratory symptoms in G1 and G2, respectively. The total number of visits to the emergency department decreased by more than 75%, from 26 (G1) to six (G2). The forced expiratory volume in 1 sec improved by a mean of 4% in G1 and 9% in G2. After application of the guidelines there was a redistribution of the degree of disease severity. In G2, there was a 12% increase in the use of long-acting beta2-stimulating sprays; 40% of the patients were using a combination of a long-acting beta2-stimulating drug and an inhaled steroid. In our experience, the use of the Global Initiative for Asthma (GINA) guidelines leads to better management of asthma patients with different degrees of severity. These findings suggest the need to perform a similar analysis in a broader setting such as a national multicenter survey in order to collect information on the challenges of putting these theoretical difficulties into practice and to compare their implementation in distinct centers.

Velocity distributions remotely measured with a single-sided NMR sensor

The pulsed field gradient nuclear magnetic resonance (PFG NMR) method has proved to be a powerful non-invasive technique to measure molecular displacement in various systems. It has been largely implemented with conventional NMR magnets where the volume for housing the flow setup is restricted. In this work we present the first approach to measure velocity distributions ex situ implementing a pulsed field gradient sequence on a single-sided NMR sensor. The open geometry of these sensors provides access to NMR measurements of a large number of applications previously excluded by the geometry of conventional closed magnets. Both, the distortions to the displacement encoding observed when implementing a PFG sequence in the presence of strongly inhomogeneous B0 and B1 fields, and the performance of the modifications proposed to eliminate these distortions are shown by means of numerical simulations. An alternating stimulated spin-echo PFG sequence implemented to remotely measure velocity distributions was combined with a multi-echo acquisition scheme to significantly increase the sensitivity of the method. The technique was implemented to measure the velocity propagator in a fluid undergoing laminar flow and good agreement with the theoretical result is observed.

3D imaging with a single-sided sensor: an open tomograph

An open tomograph to image volume regions near the surface of large objects is described. The central achievement in getting such a tomograph to work is the design of a fast two-dimensional pure phase encoding imaging method to produce a cross-sectional image in the presence of highly inhomogeneous fields. The method takes advantage of the multi-echo acquisition in a Carr-Purcell-Meiboom-Gill (CPMG)-like sequence to significantly reduce the experimental time to obtain a 2D image or to spatially resolve relaxation times across the sensitive volume in a single imaging experiment. Depending on T(2) the imaging time can be reduced by a factor of up to two orders of magnitude compared to the one needed by the single-echo imaging technique. The complete echo train decay has been also used to produce T(2) contrast in the images and to spatially resolve the T(2) distribution of an inhomogeneous object, showing that variations of structural properties like the cross-link density of rubber samples can be distinguished by this method. The sequence has been implemented on a single-sided sensor equipped with an optimized magnet geometry and a suitable gradient coil system that provides two perpendicular pulsed gradient fields. The static magnetic field defines flat planes of constant frequency parallel to the surface of the scanner that can be selected by retuning the probe frequency to achieve slice selection into the object. Combining the slice selection obtained under the presence of the static gradient of the open magnet with the two perpendicular pulsed gradient fields, 3D spatial resolution is obtained.

Multi-echo imaging in highly inhomogeneous magnetic fields

A new pulsed field gradient multi-echo imaging technique to encode position in the phase of every echo generated by a CPMG sequence in the presence of a strongly inhomogeneous static magnetic field is presented. It was applied to improve the sensitivity in an imaging experiment by adding the echo train acquired during the CPMG sequence and to spatially resolve relaxation times of inhomogeneous specimens using single-sided probes. The sequence was implemented in a new bar-magnet MOUSE equipped with a gradient coil system to apply a pulsed magnetic field with a constant gradient along one spatial coordinate. An important reduction by a factor larger than two orders of magnitude in the acquisition time was obtained compared to the previously published single-point imaging technique.

Two-dimensional imaging with a single-sided NMR probe

A new low field unilateral NMR sensor equipped with a two-dimensional gradient coil system was built. A new NMR-MOUSE concept using a simple bar magnet instead of the classical U-shaped geometry was used to produce magnetic field profiles comparatively homogeneous in extended lateral planes defining a suitable field of view for 2D spatial localization. Slice selection along the depth direction is obtained by means of the highly constant static magnetic field gradient produced by this magnet geometry. Implementing a two-dimensional phase-encoding imaging method 2D cross sections of objects were obtained with high spatial resolution. By retuning the probe it was possible to change the depth of the selected slice obtaining a 3D imaging method. The details of the construction of the new device are presented together with imaging tests to show the quality of space encoding.

Echo-planar rotating-frame imaging

A new rotating-frame imaging method that produces a complete cross section of an object in a single experiment is reported. The echo planar rotating frame imaging (EPROFI) technique uses two perpendicular RF gradients for two-dimensional spatial encoding and fully exploits the formation of rotary echoes for fast sampling of spatial frequencies. The acquisition scheme yields the Fourier transform of the spin distribution on Cartesian coordinates for straightforward image reconstruction. Implementation of the technique on a low-field portable NMR probe is described and results are presented for test objects with different geometries.

Analysis of historical porous building materials by the NMR-MOUSE

Samples of sandstone with and without deposits of silicon oxide stone strengthener as well as samples of historical brick material were analyzed by transverse NMR relaxation and mercury intrusion porosimetry. Relaxation times and relaxation time distributions of the protons from the water saturated samples were measured by low-field NMR using homogeneous and inhomogeneous fields. The measurements in inhomogeneous fields were performed with two different NMR-MOUSE sensors, one with a field gradient of 2 T/m and the other with an average field gradient of about 20 T/m. In the sandstone samples the application of stone strengtheners was shown to result in a confinement of the large pores within the outer layer of a few millimeters depth. Depending on the ferromagnetic contamination of the brick samples, the relaxation time distributions can be affected. The agreement of T2 relaxation time distributions and pore size distributions from mercury intrusion porosimetry was found to be better for the NMR-MOUSE sensors than for the homogeneous field measurements. This is true even for different brick samples, unless the content in ferromagnetic particles is very strong.

Effect of inhaled bronchodilators on inspiratory capacity and dyspnoea at rest in COPD

It has been shown that patients with chronic obstructive pulmonary disease (COPD) develop dynamic hyperinflation (DH), which contributes to dyspnoea and exercise intolerance. Formoterol, salmeterol and oxitropium have been recommended for maintenance therapy in COPD patients, but their effect on DH has only been assessed for salmeterol. The aim of the present study was to compare the acute effect of four inhaled bronchodilators (salbutamol, formoterol, salmeterol and oxitropium) and placebo on forced expiratory volume in one second, inspiratory capacity, forced vital capacity and dyspnoea in COPD patients. A cross-over, randomised, double-blind, placebo-controlled study was carried out on 20 COPD patients. Patients underwent pulmonary function testing and dyspnoea evaluation, in basal condition and 5, 15, 30, 60 and 120 min after bronchodilator or placebo administration. The results indicate that in chronic obstructive pulmonary disease patients with decreased baseline inspiratory capacity, there was a much greater increase of inspiratory capacity after bronchodilator administration, which correlated closely with the improvement of dyspnoea sensation at rest. For all bronchodilators used, inspiratory capacity reversibility should be tested at 30 min following the bronchodilator. On average, formoterol elicited the greatest increase in inspiratory capacity than the other bronchodilators used, though the difference was significant only with salmeterol and oxitropium. The potential advantage of formoterol needs to be tested in a larger patient population.

Bronchodilating effect of oxitropium bromide in heart disease patients with exacerbations of COPD: double-blind, randomized, controlled study

Anti-cholinergic agents are considered the bronchodilator therapy of first-choice in the treatment of patients with stable chronic obstructive pulmonary disease (COPD) associated with heart disease since they may be as effective or more effective than inhaled beta2-agonists and, moreover, they do not interact with cardiac beta-adrenoceptors. The aim of our study was to evaluate the bronchodilator activity of oxitropium bromide in outpatients suffering from exacerbations of COPD associated with heart diseases (ischaemic heart disease and/or arrhythmias). We recruited 50 consecutive outpatients (33 males and 17 females, mean age 68.6 years, 15 current smokers and 35 ex-smokers). Each patient performed body plethismography in basal condition and 30 min after inhalation of 200 microg metered dose inhaler (MDI) oxitropium bromide administered by a device (Fluspacer). FEV1, FVC, MMEF25-75, sRaw and tRaw were evaluated. Thirty minutes after 200 microg oxitropium bromide administration, we observed a significant improvement in FEV1 11.6% +/- 1 (mean +/- SEM) (P<0.01); FVC, MMEF25-75 sRaw variation was respectively: 9.2% +/- 0.6, 31.4 +/- 2.9, -19.9 +/- 1.1. Placebo did not significantly change pulmonary function. Our data suggest that oxitropium bromide bronchodilator activity is effective in exacerbations of COPD.

Oral vaccination with autologous platelets in chronic autoimmune thrombocytopenic purpura

Idiopathic thrombocytopenic purpura (ITP) is a common disease of autoimmune mechanism in which nearly 40% of patients need a third-line treatment after steroids and splenectomy failure. Due to the variable results of the multiple therapeutic modalities in refractory patients it is necessary to develop a more effective treatment. Following previous assays of immunotolerance with the administration of "oral vaccines", we propose a therapeutic protocol in chronic ITP patients with autologous cryopreserved or liophilized platelets administered in enteric capsules. The procedure is theoretically feasible and technically easy and does not need the isolation of the specific antigen target of the autoantibodies in each particular case.

Improving resolution in fast rotating-frame experiments

The rapid rotating-frame technique allows significant reduction in data-acquisition time compared with the two-dimensional method by stroboscopic observation of the nuclear magnetization during its evolution in the rotating frame. A onefold reduction in the dimensionality of the original rotating-frame experiment is achieved by using a train of strong radiofrequency pulses separated by short acquisition windows. The penalty for shortening experimental time is a reduction in spectral resolution compared with the two-dimensional method due to relaxation of transverse magnetization components during the observation windows. A variant of the rapid-rotating frame technique for improving spectral resolution based on undersampling and self-phase encoding is presented. An M-fold resolution improvement requires M experiments, thus, making possible a tradeoff between spectral resolution and experimental time. The technique was applied for spatial localization of quadrupole nuclei in powder solids, and resolution improvement is demonstrated on one- and two-dimensional NQR images.

Evaluation of the effects of zafirlukast 40 mg b.i.d. in addition to preexisting therapy of high-dose inhaled steroids on symptomatic patients with reversible respiratory obstruction: preliminary data

Clinical evidence of the efficacy of zafirlukast is available for mild-to-moderate asthma, but further evidence is needed on its use in the more severe forms, uncontrolled by traditional therapy. The aim of this study was to evaluate the efficacy of zafirlukast 40 mg b.i.d. as an add-on to high dose inhaled corticosteroids (HDICs). A secondary aim was to assess the drug's safety and the patients' evaluation of oral therapy and compliance. Twenty-two asthmatic patients (13 females, aged 12-70 years) taking short-acting beta 2-agonists as needed and HDICs as maintenance therapy, entered a 2-week screening phase. At the end, 18 patients with baseline forced expiratory volume (FEV)1 = 50-80% of predicted, a reversibility of > or = 15% and a > or = 10 weekly total of daytime symptom score, were given zafirlukast 40 mg b.i.d. and were reevaluated every 4 weeks for 12 weeks. Adverse events, withdrawals and changes in hematology were recorded. A diary and a questionnaire were used for subjective patient assessment. Sixteen patients (nine females, mean age 40) completed the study. Mean FEV1, (absolute value and percentage vs. predicted) was significantly higher (p < 0.05) vs. baseline after zafirlukast, with a mean improvement of 0.2 l/sec (2.4 vs. 2.2) or 6% (76% vs. 70%) of predicted. Similarly, a significant (p < 0.001) increase in peak expiratory flow was observed (6 vs. 5.5 l/sec). There was no statistically significant variation in forced expiratory flow 25-75. Analysis of the diaries showed a statistically significant reduction (p < 0.05) of morning symptoms (0.73 vs. 4.6) and of daytime symptoms score (2.3 vs. 5.3). There was no evidence of improvement in night time symptoms and use of beta 2-agonists. Three patients experienced adverse events and four suffered a single exacerbation not requiring hospital admission. Subjective evaluation was positive: 75% reported an improvement, 25% found no change and 40% particularly appreciated the oral therapy. In conclusion, treatment with zafirlukast (40 mg b.i.d.) showed a significant improvement in function parameters and symptoms. Zafirlukast was well tolerated and accepted by patients. Further research is needed, as the small number of patients does not allow definitive conclusions to be drawn.

Solid state proton imaging detected by quadrupole resonance

A double resonance method for imaging of solid materials containing quadrupole nuclei via the coupled protons is reported. The technique uses a static field gradient to encode the position on the protons and the method of double resonance spin-echo to detect the occurrence of proton resonances by affecting the zero-field echo signal from the quadrupole system. The double resonance imaging method offers the advantages of higher spatial resolution and straightforward image reconstruction for powder samples compared with rotating-frame and Zeeman-perturbated nuclear quadrupole resonance encoding techniques.

Early and delayed consolidation chemotherapy significantly improves the outcome of children with intermediate risk acute lymphoblastic leukemia. Final results of the prospective randomized PETHEMA ALL-89 TRIAL

BACKGROUND AND OBJECTIVES

To evaluate the impact of early and delayed consolidation chemotherapy on the outcome of children with acute lymphoblastic leukemia (ALL) stratified according to risk groups.

DESIGN AND METHODS

From 1989 to 1994, 195 children (< or = 15 years old) diagnosed as having ALL (ALL-L3 excluded) in 15 Spanish hospitals entered the prospective, randomized PETHEMA ALL-89 trial. Patients were stratified into low-risk (LR), intermediate-risk (IR) and high-risk (HR) groups according to their initial features and the rate of response to induction therapy. LR-ALL patients were randomized to receive or not early consolidation chemotherapy (C-1). After receiving C-1, IR patients were randomized to receive or not delayed consolidation chemotherapy (C-2). HR patients received C-1 and C-2 chemotherapy. Standard maintenance chemotherapy was administered to all patients for 2 years. High doses of intravenous methotrexate and 12 triple intrathecal doses were given as prophylaxis against central nervous system (CNS) disease.

RESULTS

The mean (and standard deviation) age was 6 (4) years and 120 patients were males. Fourteen patients had early pre-B-ALL, 149 common or pre-B-ALL, and 32 T-ALL. Complete remission (CR) was attained in 189 patients (97%), 11 of whom (6%) had a slow response. Risk group stratification after CR was: LR 89, IR 50 and HR 56 patients (including a subset of 26 patients at very high risk). Ten-year event-free survival (EFS) and overall survival (OS) probabilities for the whole series were 58% (95% CI: 52-64%) and 69% (61-77), respectively, with a median follow-up of 8.7 years. Dividing the patients according to risk group, the 10-year EFS and OS probabilities in the LR group were 71% (63-79) and 86% (80-92), respectively; in the IR group 69% (57-81) and 76% (64-88), respectively, and in the HR group 30% (18-42) and 44% (32-57), respectively. For LR patients receiving C-1, EFS and OS were 79% (57-92) and 90% (82-98), respectively, versus 62% (48-76) and 66% (51-81) in patients not receiving C-1 (p= 0.06). For IR patients, EFS and OS were significantly improved in those receiving early and delayed consolidation (EFS 87% (74-88) vs. 52% (41-70), and OS 92% (87-97) vs. 61% (51-71)(p=0.036). Prognostic factors for EFS identified in multivariable analyses were: age >10 years in the LR group (OR 3.5, 95% CI 1.3-9.5, p=0.01), and treatment with C-2 in IR patients (OR 5.0, 95% CI 1.4-17.8, p=0.01). The CNS relapse rate was 4% for all the series (including the HR subset). Tolerance to treatment was good.

INTERPRETATION AND CONCLUSIONS

In this study, early consolidation seemed to improve the prognosis of children with LR-ALL, but differences in EFS were not significant. Delayed consolidation had a favorable influence on the outcome of IR-ALL. CNS preventive treatment without cranial irradiation was effective in all the groups of ALL patients.