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Publication
Journal: European Radiology
July/14/2010
Abstract
OBJECTIVE
To determine LV function at different distances from myocardial infarction (MI) by using 3-T tagged MRI and late gadolinium enhancement (LGE).
METHODS
Cardiac MR images were acquired from 21 patients with previous MI. The harmonic phase (HARP) method was used to calculate radial and circumferential strain (RS, CS). The two strains were synchronised by subtracting the CS from the RS at the same time, and this was defined as the efficient strain (ES). Peak strain (P-RS, P-CS, P-ES) and time to peak strain (T-RS, T-CS, T-ES) were used as estimates of contractile function. Based on the presence of LGE, myocardium was classified into infarct, border zone, adjacent and remote areas.
RESULTS
P-RS and P-ES were significantly greater for remote than for adjacent and infarct areas. P-CS values were significantly greater for remote and border zone than for infarct areas. T-RS and T-ES were significantly shorter for remote and border zone than for infarct areas. T-CS was significantly shorter for border zone than for infarct areas.
CONCLUSIONS
Contractile dysfunction demonstrated by peak strain was correlated with location at different distances from the infarct. In the border zone, contractile deformation was characterised as earlier T-RS, T-CS and T-ES and greater P-CS than in the infarct area.
Publication
Journal: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
October/1/2012
Abstract
The diagnosis of cardiovascular disease requires precise assessment of both morphology and function of the heart. Currently, magnetic resonance imaging (MRI) provides a useful tool for accurate and reproducible assessment of regional function of the left ventricle noninvasively. MR tagging produces images of the heart that can be analyzed using harmonic phase (HARP) method to describe the regional function of the heart. In order to calculate regional function, a circular mesh is manually built at a specific timeframe, after which the points of such mesh are tracked using the HARP technique. The tracking is not perfect and some individual points on the mesh could fail in tracking. In this work, a new method is presented to improve the tracking by combining HARP with active contour methods. This modified HARP technique is more robust than the previous HARP technique.
Publication
Journal: Alzheimer's and Dementia
November/22/2015
Abstract
OBJECTIVE
The pathologic validation of European Alzheimer's Disease Consortium Alzheimer's Disease Neuroimaging Initiative Center Harmonized Hippocampal Segmentation Protocol (HarP).
METHODS
Temporal lobes of nine Alzheimer's disease (AD) and seven cognitively normal subjects were scanned post-mortem at 7 Tesla. Hippocampal volumes were obtained with HarP. Six-micrometer-thick hippocampal slices were stained for amyloid beta (Aβ), tau, and cresyl violet. Hippocampal subfields were manually traced. Neuronal counts, Aβ, and tau burden for each hippocampal subfield were obtained.
RESULTS
We found significant correlations between hippocampal volume and Braak and Braak staging (ρ = -0.75, P = .001), tau (ρ = -0.53, P = .034), Aβ burden (ρ = -0.61, P = .012), and neuronal count (ρ = 0.77, P < .001). Exploratory subfield-wise significant associations were found for Aβ in Cornu Ammonis (CA)1 (ρ = -0.58, P = .019) and subiculum (ρ = -0.75, P = .001), tau in CA2 (ρ = -0.59, P = .016), and CA3 (ρ = -0.5, P = .047), and neuronal count in CA1 (ρ = 0.55, P = .028), CA3 (ρ = 0.65, P = .006), and CA4 (ρ = 0.76, P = .001).
CONCLUSIONS
The observed associations provide pathological confirmation of hippocampal morphometry as a valid biomarker for AD and pathologic validation of HarP.
Publication
Journal: Nucleus
January/3/2012
Abstract
The SNF2 family of ATPases acts in the context of chromatin to regulate transcription, replication, repair and recombination. Defects in SNF2 genes cause many human diseases. For example, mutations in SMARCAL1 (also named HARP) cause Schimke immuno-osseous dysplasia (SIOD); a multi-system disorder characterized by growth defects, immune deficiencies, renal failure and other complex phenotypes. Several groups including ours recently identified SMARCAL1 as a replication stress response protein. Importantly, SMARCAL1 localizes to stalled replication forks and this localization of SMARCAL1 activity prevents DNA damage accumulation during DNA replication. We determined that SIOD-related SMARCAL1 mutants could not prevent replication-associated DNA damage in cells in which endogenous SMARCAL1 was silenced, establishing the first link between SIOD and a defect in a specific biological activity. Here, we also report that cells from patients with SIOD exhibit elevated levels of DNA damage that can be rescued by re-introduction of wild-type SMARCAL1. Our data suggest that loss of SMARCAL1 function in patients may cause DNA replication-associated genome instability that contributes to the pleiotropic phenotypes of SIOD.
Publication
Journal: Journal of Applied Physiology
August/21/1997
Abstract
Volume changes in the spleens of hooded seals (Cystophora cristata) and harp seals (Phoca groenlandica) were measured plethysmographically in vitro in response to epinephrine, norepinephrine, isoprenaline, phentolamine, and acetylcholine. Dilated spleens contracted forcefully within 1-3 min of alpha-adrenoceptor activation with 1.0-5.0 micrograms epinephrine/kg body mass, whereas stimulation of beta-adrenoceptors and cholinergic receptors had little effect. The mass of dilated hooded seal spleens corresponded to 2-4% (n = 7) of body mass, with volume (V; ml) relating to body mass (M; kg) as follows: V = 12.0M + 910 (r2 = 0.96, n = 4). Thus the spleen of a 250-kg hooded seal maximally expels 3.9 liters, or 13%, of its estimated total blood volume. Average hematocrit in splenic venous outflow from dilated spleens was 90 +/- 3% (n = 3) in hooded seals and 85% (n = 2) in harp seals. From these data we have estimated that the aerobic diving limit of a 250-kg hooded seal increases only 105 s, at the most, if complete emptying of the spleen occurs during diving, while the corresponding estimate for a 112-kg harp seal is 80 s.
Publication
Journal: Biological Reviews
April/28/1993
Abstract
This review presents summary figures of, and fits growth curves to, data on body lengths (as standard length, SL, whenever possible) of pinnipeds at ages estimated to O.I y. (1) Generalized von Bertalanffy (vB) growth curves are fitted to most data: Lx = L infinity (I - ea(x-x0)b, Lx is length at age x, x0 is the origin of the curve (here chosen a priori as time of initiation of embryonic growth), L infinity is asymptotic length, a (which is negative) determines rate of approach to the asymptote, and b influences the 'shape' of the approach. (2) No single monotonic growth equation suffices for growth in length, which is linear before birth and remains so during early life. The vB equation is only suitable to describe mean lengths of newborns, and animals one or more years old. (3) Also, for males of polygynous species, two functions are needed to account for accelerated growth at puberty. Generally a Gompertz equation is adequate for adult males of these species. (4) The fitted growth equations permit statistical comparisons of sizes and growth rates, as well as of individual variability (as growth-curve residuals), among populations and species. (5) For the following species (including different populations when available), the reliability of data is assessed and parameters of growth curves are presented (with sexes separated where significantly different): walrus, California and Steller sea lions, Antarctic, subantarctic and northern fur seals, Hawaiian monk seal, crabeater, Weddell and Leopard seals, southern and northern elephant seals, bearded, hooded, ringed, Baikal, Caspian, spotted, harbour, harp, ribbon and grey seals. (6) Some novel findings pertain to individual species as follows. Although the Pacific walrus is generally stated to be the larger subspecies, females from Hudson Bay and males from Foxe Basin, in the eastern Canadian Arctic, may be as long as those from the Bering Sea. Although female Weddell seals have been assumed to grow larger than males, there is no significant difference in growth curves fitted to the most complete data. Uniquely among populations examined, the relative variability (absolute growth curve residuals/predicted lengths) of male southern elephant seals is amplified with age. Among ringed seals from Svalbard, the eastern, western and high Canadian Arctic, and the Bering, Chukchi, Okhotsk, Barents and Baltic Seas, asymptotic sizes are larger among those that breed on land-fast ice rather than floes, and size may be more variable in more extreme Arctic environments. The Baikal seal is confirmed as the smallest species of pinniped.(ABSTRACT TRUNCATED AT 400 WORDS)
Publication
Journal: Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
January/20/2010
Abstract
Pinnipeds rely on muscle oxygen stores to help support aerobic diving, therefore muscle maturation may influence the behavioral ecology of young pinnipeds. To investigate the pattern of muscle development, myoglobin concentration ([Mb]) and acid buffering ability (beta) was measured in ten muscles from 23 harp and 40 hooded seals of various ages. Adult [Mb] ranged from 28-97 to 35-104 mg g tissue(-1) in harp and hooded seals, respectively, with values increasing from the cervical, non-swimming muscles to the main swimming muscles of the lumbar region. Neonatal and weaned pup muscles exhibited lower (approximately 30% adult values) and less variable [Mb] across the body than adults. In contrast, adult beta showed little regional variation (60-90 slykes), while high pup values (approximately 75% adult values) indicate significant in utero development. These findings suggest that intra-uterine conditions are sufficiently hypoxic to stimulate prenatal beta development, but that [Mb] development requires additional postnatal signal such as exercise, and/or growth factors. However, because of limited development in both beta and [Mb] during the nursing period, pups are weaned with muscles with lower aerobic and anaerobic capacities than those of adults.
Publication
Journal: Magnetic Resonance in Medicine
December/13/2001
Abstract
Magnetic resonance tagging has proven a valuable tool in the quantification of myocardial deformation. However, time-consuming postprocessing has discouraged the use of this technique in clinical routine. Recently, the harmonic phase (HARP) technique was introduced for automatic calculation of myocardial strain maps from tagged images. In this study, a comparison was made between HARP instantaneous strain maps calculated from single tagged images (SPAMM) and those calculated from subtracted tagged images (CSPAMM). The performance was quantified using simulated images of an incompressible cylinder in the 'end-systolic' state with realistic image contrast and noise. The error in the second principal stretch ratio was 0.009 +/- 0.032 (mean +/- SD) for the SPAMM acquisition, and 0.007 +/- 0.016 for CSPAMM at identical contrast-to-noise ratio. Furthermore, differences between the methods were illustrated with in vivo strain maps. Those calculated from CSPAMM images showed fewer artifacts and were less sensitive to the choice of cut-off frequencies in the HARP band-pass filter. A prerequisite for the method to become practical is that the CSPAMM images should be acquired in a single breathhold.
Publication
Journal: Veterinary Pathology
July/9/2009
Abstract
Gas bubbles were found in 15 of 23 gillnet-drowned bycaught harp (Pagophilus groenlandicus), harbor (Phoca vitulina) and gray (Halichoerus grypus) seals, common (Delphinus delphis) and white-sided (Lagenorhyncus acutus) dolphins, and harbor porpoises (Phocaena phocaena) but in only 1 of 41 stranded marine mammals. Cases with minimal scavenging and bloating were chilled as practical and necropsied within 24 to 72 hours of collection. Bubbles were commonly visible grossly and histologically in bycaught cases. Affected tissues included lung, liver, heart, brain, skeletal muscle, gonad, lymph nodes, blood, intestine, pancreas, spleen, and eye. Computed tomography performed on 4 animals also identified gas bubbles in various tissues. Mean +/- SD net lead line depths (m) were 92 +/- 44 and ascent rates (ms(-1)) 0.3 +/- 0.2 for affected animals and 76 +/- 33 and 0.2 +/- 0.1, respectively, for unaffected animals. The relatively good carcass condition of these cases, comparable to 2 stranded cases that showed no gas formation on computed tomography (even after 3 days of refrigeration in one case), along with the histologic absence of bacteria and autolytic changes, indicate that peri- or postmortem phase change of supersaturated blood and tissues is most likely. Studies have suggested that under some circumstances, diving mammals are routinely supersaturated and that these mammals presumably manage gas exchange and decompression anatomically and behaviorally. This study provides a unique illustration of such supersaturated tissues. We suggest that greater attention be paid to the radiology and pathology of bycatch mortality as a possible model to better understand gas bubble disease in marine mammals.
Publication
Journal: Physiological and Biochemical Zoology
April/27/2000
Abstract
We investigated the effects of a change from a high-fat diet to a low-fat diet of differing fatty acid (FA) composition on the body composition and blubber FA of five captive juvenile harp seals. Seals that had been maintained for 1 yr on a diet of Atlantic herring >>/=9% fat) were switched to a diet of Atlantic pollock (1. 7% fat) for 30 d. On days 0, 14, and 30, mass and body composition (using isotope dilution) were measured, and blubber biopsies (5 cmx6 mm) were taken for FA analysis. Fat accounted for 38%-49% of body mass at the start of the experiment. When switched to the pollock diet, and despite food intakes averaging 6.5 kg/d (32.3 MJ/d), body fat declined by an average of 6.4 kg or by 32% over the 30-d experiment. In contrast, body protein increased in direct relation to protein intake (r2=0.836, P=0.030). Despite substantial loss of body fat, blubber FA signature changed significantly to reflect the changes in dietary intake of FA, and the deposition of FA was quantifiably predictable. Our results suggest that young growing phocids are unable to maintain body fat stores on low-fat diets even when protein intakes are high. This may have significant implications for juvenile pinniped survival in the wild. In addition, turnover and deposition of dietary FA in blubber takes place in nonfattening seals.
Publication
Journal: Veterinary Record
August/16/1999
Abstract
Between 1983 and 1996 a total of 1386 samples of serum were taken from four species of seal and three species of whale in the waters west of Iceland, the area of pack-ice north-west of Jan Mayen, the northern coast of Norway and the Kola Peninsula, the waters west of Svalbard, and the Barents Sea; they were tested for the presence of anti-Brucella antibodies with an indirect ELISA (protein G conjugate). The positive sera were re-tested with classical brucellosis serological tests, such as the serum agglutination test, the EDTA-modified serum agglutination test, the Rose Bengal test, and the complement fixation test, as well as an anti-complement ELISA. Anti-Brucella antibodies were detected in all the species investigated, except for the bearded seal (Erignathus barbatus), with the following prevalences: hooded seals (Cystophora cristata) 35 per cent; harp seals (Phoca groenlandica) 2 per cent; ringed seals (Phoca hispida) 10 per cent; minke whales (Balaenoptera acutorostrata) 8 per cent; fin whales (Balaenoptera physalus) 11 per cent; and sei whales (Balaenoptera borealis) 14 per cent. An isolate belonging to the genus Brucella was obtained from the liver and spleen of one of the seropositive minke whales. The findings suggest that antibodies against the surface lipopolysaccharide of Brucella species are widely distributed among marine mammals in the North Atlantic Ocean.
Publication
Journal: Prostate
February/23/1999
Abstract
BACKGROUND
Heparin affin regulatory peptide (HARP) composes, together with midkine (MK), a new family of heparin-binding growth/differentiation factors. Recently, HARP was incriminated in cancer progression, as an angiogenic factor and as a tumor growth factor. In this study, we analyzed the possible involvement of HARP in human prostate cancer (Pca).
METHODS
The localization of HARP protein and its mRNAs in normal prostate (n = 5), benign prostate hyperplasia (BPH) (n = 7), and prostate cancer (Pca) (n = 9) was analyzed by immunohistochemistry and in situ hybridization. The mitogenic activity of this growth factor for prostate epithelial cells was determined with a thymidine incorporation assay. HARP cDNA was transfected into normal prostate epithelial (PNT-1A) cells, and their growth was evaluated by soft-agar growth assay.
RESULTS
We found HARP protein associated with epithelial cells in PCa but not in normal prostate or BPH, while the corresponding mRNAs were located in the stromal compartment. Furthermore, HARP is mitogenic for PNT-1A, LNCaP, and DU-145 cells. Overexpression of the human HARP in PNT-1A transfected cells induced both anchorage-independent growth and growth at low serum concentrations.
CONCLUSIONS
Our results suggest that HARP may act in a paracrine manner from mesenchymal to tumoral epithelial cells, and may play a role in the molecular mechanisms that regulate prostate tumor cell growth.
Publication
Journal: Lipids
February/28/1993
Abstract
Long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) of marine oils are important dietary components for both infants and adults, and are incorporated into milks following maternal dietary intake. However, little is known about the hydrolysis of these PUFA from milk triglycerides (TG) by lipases in suckling young. Seals, like humans, possess gastric lipase; however, the milk lipids of seals and sea lions are almost devoid of the readily hydrolyzable medium-chain fatty acids, and are characterized by a large percentage (10-30%) of n-3 PUFA. Gastric hydrolysis of milk lipids was studied in vivo in suckling pups of three species (the California sea lion, the harp seal and the hooded seal) in order to elucidate the actions and specificity of gastric lipases on milk TG in relation to fatty acid composition and TG structure. Regardless of milk fat content (31-61% fat) or extent of gastric hydrolysis (10-56%), the same fatty acids were preferentially released in all three species, as determined by their relative enrichment in the free fatty acid (FFA) fraction. In addition to 16:1 and 18:0, these were the PUFA of 18 carbons and longer, except for 22:6n-3. Levels of 20:5n-3 were most notably enriched in FFA, at up to five times that found in the TG. Although 22:6n-3 was apparently also released from the TG (reduced in the diglyceride), it was also notably reduced in FFA.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication
Journal: Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
February/19/2017
Abstract
We have developed a novel highly articulated robotic probe (HARP) that can thread through tightly packed volumes without disturbing the surrounding tissues and organs. We use cardiac surgery as the focal application of this work. As such, we have designed the HARP to enter the pericardial cavity through a subxiphoid port. The surgeon can effectively reach remote intrapericardial locations on the epicardium and deliver therapeutic interventions under direct control. Our device differs from others in that we use conventional actuation and still have great maneuverability. We have performed proof-of-concept clinical experiments to give us preliminary validation of the ideas presented here.
Publication
Journal: Journal of Experimental Biology
October/30/2003
Abstract
The anatomy and mechanics of the fore-wings of the Australian cricket Teleogryllus oceanicus were examined to study how resonances of the wings were excited, to model the interactions between the two wings during sound production, to account for the frequency changes that occur within the pulses and to determine the variation in sound amplitude during the pulses. Sound is produced after raising the wings by closing the right wing over the left; the plectrum of the left wing engages and releases teeth on the file on the underside of the right wing. The mean number of teeth on the right file is 252; the teeth are more closely spaced in the posterior part of the file, which is engaged at the start of the song pulses. The anterior part of the file is separated from the base of the harp by a short flexible region. The dorsal field of the wing, in which the harp is situated, is largely mechanically isolated from the driving veins of the lateral field, except for a cross vein at the apex of the harp. The harps of the two wings did not differ significantly in area but the plectrum of the left wing was significantly longer and wider than that of the right wing. The posterior edge of the plectrum has a radius of approximately 0.5 micro m, which allows it to engage the 20 micro m-tall teeth of the file. The plectrum is separated from the wing by a 0.5 micro m-thick crescent that allows it to twist lengthways and thus disengage the file teeth. The sigmoid shape of the file allows the plectrum to engage teeth over most of the length of the file. The calling song of T. oceanicus consists of a chirp of four similar pulses followed by a trill of pairs of pulses. The dominant frequency of all pulses is approximately 4.8 kHz but cycle-by-cycle analysis suggests that the different types of pulse are produced by wing-closing movements through different arcs. Free resonances of the left wing occurred at 4.56 kHz [quality factor (Q)=25.1] and of the right wing at 4.21 kHz (Q=23.9). Driven by loud sound, maximum vibration of the harp was seen at approximately 4.5 kHz; at lower sound levels, the vibration was confined to the cross-veins of the harp that extend distally from the file. Resonances of the left wing driven by vibration of the same wing, either at the plectrum or on the anal area, occurred at similar frequencies to those of the songs and had similar Qs but were approximately anti-phase, demonstrating that movement of the plectrum (e.g. by the file teeth) causes an opposite movement of the harp. When the right wing was driven directly on the file, the resonant frequency was 5.88 kHz but, when driven on the file via a length of the left file and the left plectrum, it was 4.83 kHz. The amplitude of the vibration increased from the posterior end of the file to the middle then fell towards the anterior end of the file. Pushing a left plectrum across the middle of the right file produced trains of damped sound pulses at 4.82 kHz (Q=23.4). Clicks excited from the anterior end of the file had lower frequencies. The resonances excited from both the left wing via its plectrum and from the right wing when driven via the left plectrum were similar in frequency to that of the song. The resonance of the dorsal field persisted after ablation of the harp but the mean resonant frequency increased 1.12-fold with a similar Q to the intact wing. Droplets of water on the distal end of the harp or proximal part of the dorsal field raised the resonant frequency. The resonant frequency was lowered by the addition of weights to the harp or the file; the factor of the decrease suggested that the mass of the resonant system was approximately 1.4 mg, which accords with the mass of the harp plus file plus anal area of the wing (left wing, 1.27 mg; right wing, 1.15 mg) but is far heavier than the harp (0.22 mg). An earlier suggestion that the harp is the resonator is not supported; instead, it is proposed that the major elastic component of the resonant system is the file plus 1st anal vein and that the mass component is the combined mass of the file, anal area and harp.
Publication
Journal: Journal of the Acoustical Society of America
November/13/1991
Abstract
To assess the risk of noise-induced hearing loss among musicians in the Chicago Symphony Orchestra, personal dosimeters set to the 3-dB exchange rate were used to obtain 68 noise exposure measurements during rehearsals and concerts. The musicians' Leq values ranged from 79-99 dB A-weighted sound pressure level [dB(A)], with a mean of 89.9 dB(A). Based on 15 h of on-the-job exposure per week, the corresponding 8-h daily Leq (excluding off-the-job practice and playing) ranged from 75-95 dB(A) with a mean of 85.5 dB(A). Mean hearing threshold levels (HTLs) for 59 musicians were better than those for an unscreened nonindustral noise-exposed population (NINEP), and only slightly worse than the 0.50 fractile data for the ISO 7029 (1984) screened presbycusis population. However, 52.5% of individual musicians showed notched audiograms consistent with noise-induced hearing damage. Violinists and violists showed significantly poorer thresholds at 3-6 kHz in the left ear than in the right ear, consistent with the left ear's greater exposure from their instruments. After HTLs were corrected for age and sex, HTLs were found to be significantly better for both ears of musicians playing bass, cello, harp, or piano and for the right ears of violinists and violists than for their left ears or for both ears of other musicians. For 32 musicians for whom both HTLs and Leq were obtained, HTLs at 3-6 kHz were found to be correlated with the Leq measured.
Publication
Journal: Journal of Cardiovascular Magnetic Resonance
November/13/2018
Abstract
BACKGROUND
Myocardial strain is increasingly recognized as an important assessment for myocardial function. In addition, it also improves outcome prediction. However, there is lack of standardization in strain evaluation by cardiovascular magnetic resonance (CMR). In this study we compared strain values using multiple techniques and multiple vendor products.
METHODS
Prospectively recruited patients with cardiomyopathy of diverse etiology (N = 77) and healthy controls (N = 10) underwent CMR on a 1.5 T scanner. Tagging, displacement encoding with stimulated echoes (DENSE) and balanced stead state free precession cine imaging were acquired on all subjects. A single matched mid left ventricular (LV) short axis plane was used for the comparisons of peak circumferential (Ecc) and radial strain (Err) and a 4-chamber view for longitudinal strain (Ell). Tagging images were analyzed using harmonic phase (HARP) and displacement encoding with stimulated echoes (DENSE) images using a proprietary program. Feature tracking (FT) was evaluated using 3 commercially available software from Tomtec Imaging Systems, Cardiac Image Modeller (CIM), and Circle Cardiovascular Imaging. Tagging data were used as reference. Statistic analyses were performed using paired t-test, intraclass correlation coefficient (ICC), Bland Altman limits of agreement and coefficient of variations.
RESULTS
Average LV ejection fraction was 50% (range 32 to 62%). Regional LV wall motion abnormalities were present in 48% of the analyzed planes. The average Ecc was - 13 ± 4%, - 13 ± 4%, - 16 ± 6%, - 10 ± 3% and - 14 ± 4% for tagging, DENSE, Tomtec, CIM and Circle, respectively, with the best agreement seen in DENSE and Circle with tagging. The Err was highly varied with poor agreement across the techniques, 32 ± 24%, 40 ± 28%, 47 ± 26%, 64 ± 33% and 23 ± 9% for tagging, DENSE, Tomtec, CIM and Circle, respectively. The average Ell was - 14 ± 4%, - 8 ± 3%, - 13 ± 5%, - 11 ± 3% and - 12 ± 4% for tagging, DENSE, Tomtec, CIM and Circle, respectively with the best agreement seen in Tomtec and Circle with tagging. In the intra- and inter-observer agreement analysis the reproducibility of each technique was good except for Err by HARP.
CONCLUSIONS
Small but important differences are evident in Ecc and Ell comparisons among vendors while large differences are seen in Err assessment. Our findings suggest that CMR strain values are technique and vendor dependent. Hence, it is essential to develop reference standard from each technique and analytical product for clinical use, and to sequentially compare patient data using the same software.
Publication
Journal: Australian Journal of Primary Health
March/1/2011
Abstract
As part of the Department of Human Services Hospital Admissions Risk Program (HARP), a group of acute and community based health care providers located in the western suburbs of Melbourne formed a consortium to reduce the demand on hospital emergency services and improve health outcomes for patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). The model of care was designed by a team of multidisciplinary specialists and medical consultants. In addition to receiving normal care, patients recruited to the project were assessed by 'Care Facilitators', who identified unmet health care needs and provided information, advice and education for the patient concerning their condition and self-management. Patients declining recruitment received all normal care services. The patients' rates of emergency department (ED) presentations, inpatient admissions and hospital inpatient bed-days before and after their recruitment were calculated from the Western Health patient activity records, and pre- versus post-recruitment rates were compared using ANOVA. Changes relative to the ongoing use by those who declined recruitment were compared using the group-by-time interaction. Patient health outcomes were assessed using established disease-specific tools, and pre- versus post-recruitment values were compared using paired t-tests. Patients recruited to the COPD project reduced (P<0.05) their emergency presentations, admissions and hospital inpatient bed-days by 10, 25 and 18%, respectively, whereas those declining recruitment increased their usage by 45, 41 and 51% respectively. Recruited CHF patients also displayed reductions in emergency presentations (39%), admissions (36%) and hospital inpatient bed-days (33%), whereas those who declined recruitment displayed lesser reductions for ED presentations (26%) and admissions (20%), and increased their use of hospital inpatient bed-days (15%). The recruited COPD patients reported a significant reduction in their symptoms (P<0.005) and the CHF patients reported an improvement in their overall health and quality of life scores (P<0.001). The outcome measures used in this evaluation suggest that an integrated care facilitation model that is patient focussed, provides an education component to promote greater self-management compliance and delivers a continuum of care through the acute and community health sectors, may reduce the utilisation of acute health care facilities and benefit the patient.
Publication
Journal: Journal of Cardiovascular Magnetic Resonance
September/15/2015
Abstract
BACKGROUND
Displacement Encoding with Stimulated Echoes (DENSE) encodes displacement into the phase of the magnetic resonance signal. Due to the stimulated echo, the signal is inherently low and fades through the cardiac cycle. To compensate, a spiral acquisition has been used at 1.5T. This spiral sequence has not been validated at 3T, where the increased signal would be valuable, but field inhomogeneities may result in measurement errors. We hypothesized that spiral cine DENSE is valid at 3T and tested this hypothesis by measuring displacement errors at both 1.5T and 3T in vivo.
METHODS
Two-dimensional spiral cine DENSE and tagged imaging of the left ventricle were performed on ten healthy subjects at 3T and six healthy subjects at 1.5T. Intersection points were identified on tagged images near end-systole. Displacements from the DENSE images were used to project those points back to their origins. The deviation from a perfect grid was used as a measure of accuracy and quantified as root-mean-squared error. This measure was compared between 3T and 1.5T with the Wilcoxon rank sum test. Inter-observer variability of strains and torsion quantified by DENSE and agreement between DENSE and harmonic phase (HARP) were assessed by Bland-Altman analyses. The signal to noise ratio (SNR) at each cardiac phase was compared between 3T and 1.5T with the Wilcoxon rank sum test.
RESULTS
The displacement accuracy of spiral cine DENSE was not different between 3T and 1.5T (1.2 ± 0.3 mm and 1.2 ± 0.4 mm, respectively). Both values were lower than the DENSE pixel spacing of 2.8 mm. There were no substantial differences in inter-observer variability of DENSE or agreement of DENSE and HARP between 3T and 1.5T. Relative to 1.5T, the SNR at 3T was greater by a factor of 1.4 ± 0.3.
CONCLUSIONS
The spiral cine DENSE acquisition that has been used at 1.5T to measure cardiac displacements can be applied at 3T with equivalent accuracy. The inter-observer variability and agreement of DENSE-derived peak strains and torsion with HARP is also comparable at both field strengths. Future studies with spiral cine DENSE may take advantage of the additional SNR at 3T.
Publication
Journal: Journal of Magnetic Resonance Imaging
February/21/2007
Abstract
OBJECTIVE
To discuss differences between displacement encoding with stimulated echoes (DENSE) and the harmonic phase (HARP) in imaging and reconstruction strategies.
METHODS
HARP and DENSE are presented in their historical context: while the HARP method was developed from the framework of myocardial tagging, DENSE arose from the framework of stimulated echo and displacement encoding using bipolar gradients. Both techniques have evolved since their introduction, thereby becoming more similar over time and losing their distinct features. Newly introduced improvements have successfully been applied in both methods. Differences between both methods are discussed point by point.
RESULTS
From this discussion it follows that almost all apparent differences are in fact nonexistent.
CONCLUSIONS
In the literature, both techniques are still regarded as distinctly different techniques, where a more general treatment of the technique is justified. Once it is realized that both frameworks are easily merged, the benefits are 1) less confusion about the (dis)advantages of either technique, and 2) understanding of phase-based strain imaging that is more general than HARP or DENSE alone.
Publication
Journal: Journal of Magnetic Resonance Imaging
October/13/2010
Abstract
OBJECTIVE
To validate a method for measuring 3D left ventricular (LV) strain from phase-unwrapped harmonic phase (HARP) images derived from tagged cardiac magnetic resonance imaging (MRI).
METHODS
A set of 40 human subjects were imaged with tagged MRI. In each study the HARP phase was computed and unwrapped in each short-axis and long-axis image. Inconsistencies in unwrapped phase were resolved using branch cuts manually placed with a graphical user interface. 3D strain maps were computed for all imaged timeframes in each study. The strain from unwrapped phase (SUP) and displacements were compared to those estimated by a feature-based (FB) technique and a HARP technique.
RESULTS
3D strain was computed in each timeframe through systole and mid-diastole in approximately 30 minutes per study. The standard deviation of the difference between strains measured by the FB and the SUP methods was less than 5% of the average of the strains from the two methods. The correlation between peak circumferential strain measured using the SUP and HARP techniques was over 83%.
CONCLUSIONS
The SUP technique can reconstruct full 3D strain maps from tagged MR images through the cardiac cycle in a reasonable amount of time and user interaction compared to other 3D analysis methods.
Publication
Journal: The American journal of anatomy
June/19/1984
Abstract
Extensive morphometric measurements were made on the vestibular system of the rabbit ( Oryctulagus cuniculus), the gerbil (Meriones unguiculatus), the chinchilla (Chinchilla laniger ), and the squirrel monkey (Saimiri sciureus) from serial sections of temporal bones. Additionally, a more limited set of measurements were also completed on the owl monkey (Aotus trivirgatus), the Capuchin monkey (Cebus sp.), the harp seal ( Pagophilus groenlandicus Erxleben , 1777), and the two-toed sloth ( Choloepus sp.). The following measurements were made: 1) radius of curvature (R) of each membranous semicircular canal (herein called semicircular duct-see nomenclature in Nomina Anatomica (1968) ), 2) cross-sectional diameter of the ducts and the osseous semicircular canals, and 3) some pertinent morphometrics of the cristae ampullares and the utricle. In all species studied 1) the radii of curvature of the three semicircular ducts are dissimilar, with that of the lateral duct being as small as, or smaller than, those of the anterior and posterior ducts; 2) R for the anterior duct is largest in the harp seal and the rabbit; 3) the canal and duct dimensions are largest in the Capuchin and squirrel monkeys, the two-toed sloth, and the harp seal, and smallest in the gerbil; 4) the proportion of otic fluid "space" that is occupied by endolymph shows a ranking of gerbil greater than rabbit greater than two-toed sloth greater than chinchilla = owl monkey greater than squirrel monkey greater than Capuchin monkey greater than harp seal; and 5) the gross ampullary and utricular dimensions are largest in the harp seal and smallest in the gerbil. These measurements were used for determining the time constants describing semicircular-canal dynamics in the Steinhausen (1931, 1933) and Oman -Marcus (1980) equations.
Publication
Journal: Transplantation
April/3/2014
Abstract
BACKGROUND
Laparoscopic donor nephrectomy (LDN) has become the gold standard for live-donor nephrectomy, as it results in a short convalescence time and increased quality of life. However, intraoperative safety has been debated, as severe complications occur incidentally. Hand-assisted retroperitoneoscopic donor nephrectomy (HARP) is an alternative approach, combining the safety of hand-guided surgery with the benefits of endoscopic techniques and retroperitoneal access. We assessed the best approach to optimize donors' quality of life and safety.
METHODS
In two tertiary referral centers, donors undergoing left-sided nephrectomy were randomly assigned to HARP or LDN. Primary endpoint was physical function, one of the dimensions of the Short Form-36 questionnaire on quality of life, at 1 month postoperatively. Secondary endpoints included intraoperative events and operation times. Follow-up was 1 year.
RESULTS
In total, 190 donors were randomized. Physical function at 1 month follow-up did not significantly differ between groups (estimated difference, 1.79; 95% confidence interval, -4.1 to 7.68; P=0.55). HARP resulted in significantly shorter skin-to-skin time (mean, 159 vs. 188 min; P<0.001), shorter warm ischemia time (2 vs. 5 min; P<0.001) and a lower intraoperative event rate (5% vs. 11%, P=0.117). Length of stay (both 3 days; P=0.135) and postoperative complication rate (8% vs. 8%; P=1.00) were not significantly different. Potential graft-related complications did not significantly differ (6% vs. 13%; P=0.137).
CONCLUSIONS
Compared with LDN, left-sided HARP leads to similar quality of life, shorter operating time, and warm ischemia time. Therefore, we recommend HARP as a valuable alternative to the laparoscopic approach for left-sided donor nephrectomy.
Publication
Journal: Journal of Assisted Reproduction and Genetics
March/5/2017
Abstract
OBJECTIVE
The purpose of this study was to examine the effects of psychosocial interventions on the mental health, pregnancy rates, and marital function of infertile couples undergoing in vitro fertilization (IVF), as determined through RCT studies.
METHODS
Using the electronic databases PubMed, EMBase, Cochrane Library, CINAHL, PsycInfo, and CAJ, a systematic literature search was conducted in July 2015. MeSH terms, key words, and free words such as "infertility," "fertilization in vitro," "psychotherapy," "intervention," "anxiety," "depression," and "marital satisfaction" were used to identify all potential studies. The quality of the studies that were included was assessed using the risk of bias assessment tool developed by the Cochrane Back Review Group. Descriptive analysis was adopted to synthesize the results.
RESULTS
A total of 20 randomized controlled trials were included in this review. There were reports of positive effects on the anxiety levels, pregnancy rates, or marital function of infertile couples in six studies that adopted different psychosocial approaches, including mind body intervention (Eastern body-mind-spirit, Integrative body-mind-spirit, and Mind/body intervention), cognitive behavioral therapy, group psychotherapy, and harp therapy. However, there were methodological or practical issues related to measurement points and attrition rates in these studies. None of these interventions were found to be efficacious in relieving the depression or stress of individuals or couples undergoing IVF treatment. None of the included studies tackled or measured the mental health status of the couples during the most stressful time of waiting for the pregnancy results of their treatment.
CONCLUSIONS
A complex intervention, based on sound evidence, should be developed targeting both females and males of infertile couples undergoing IVF treatment, particularly during the stressful period of waiting for the results of the pregnancy test result and after failed cycles.
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