bluuebunny/crossref_metadata_2025 huggingface dataset:
THALLUS DIFFERENTIATION OF PHOTOSYNTHESIS, GROWTH, REPRODUCTION, AND UV‐B SENSITIVITY IN THE GREEN ALGA ULVA PERTUSA (CHLOROPHYCEAE)1
Authors: Han Taejun , Han Young‐Seok , Kain Joanna M. , Häder Donat‐P.
Published: July 2003

The chlorophyte Ulva is perceived as a simple and uniform algal form, with little functional differentiation within a thallus. We compared morphology, pigmentation, photosynthesis, growth, reproduction, and UV‐B sensitivity between different thallus regions of Ulva pertusa Kjellman. Thallus thickness and cell size were significantly greater, whereas cell number was less in the basal region than in other regions. Photosynthetic pigment contents were lowest in the basal region and increased toward the marginal region. Photosynthetic capacity and photosynthetic efficiency normalized to fresh weight, area, volume, and cell number showed a progressive increase from the basal to marginal parts; however, on a chl basis those values were equal regardless of thallus part. Values of light saturation point were not statistically different between regions. Growth rates increased from marginal to basal and to middle parts of the thallus, whereas sporulation was highest in marginal (100%) followed by middle (30%) and basal parts (0%). Daily observation over 9 days showed that 56% of the basal cells divided once and did not produce spores, whereas every marginal cell went through its first division and 89% of the primary daughter cells also divided, resulting in 100% sporulation. A 7‐day treatment with PAR and PAR + UV‐A caused a significant decrease in the effective quantum yield of all thallus regions, followed by a recovery toward the initial values, whereas PAR + UV‐A + UV‐B irradiation led to greater photoinhibition and less recovery. Marked differences in the UV‐B sensitivity were observed, with marginal parts being more sensitive and basal parts most resistant.
NEW INSIGHTS IN THE TAXONOMY OF THE CERAMIUM SINICOLA COMPLEX: RESURRECTION OF CERAMIUM INTERRUPTUM (CERAMIACEAE, RHODOPHYTA)1
Authors: Cho Tae Oh , Fredericq Suzanne , Murray Steven N. , Boo Sung Min
Published: July 2003

Phylogenetic relationships of the Ceramium sinicola complex (C. interruptum and C. sinicola) including C. codicola were studied using nucleotide sequences of rbcL and small subunit rDNA, and the RUBISCO spacer was used for sequence comparison of each species. A reassessment of the taxonomic rank and the evolutionary trend within the complex was inferred from a comparative morphological study and molecular data sets based on 11 samples from eight populations from the Pacific coast of the United States and Mexico. Intraspecific relationships were poorly resolved, but the resurrection of C. interruptum as a distinct species was strongly supported by both morphological and molecular data. Ceramium interruptum is distinguished by the combination of the following features: thalli uncorticated at the first internode above the dichotomy, presence of four corticating filaments, 7–11 segments between branching points, rhizoids digitate, and epiphytic on a variety of hosts. Our molecular analyses show that C. sinicola is the sister group to C. codicola, and C. interruptum is basal to them. These phylogenetic relationships allowed for an assessment of the trend in the evolution of cortication pattern and attachment mode to the host.
PROBING THE SURFACE OF LIVING DIATOMS WITH ATOMIC FORCE MICROSCOPY: THE NANOSTRUCTURE AND NANOMECHANICAL PROPERTIES OF THE MUCILAGE LAYER1
Authors: Higgins Michael J. , Sader John E. , Mulvaney Paul , Wetherbee Richard
Published: July 2003

Atomic force microscopy (AFM) is used to investigate the topography and material properties of the mucilage layer of live cells of three benthic diatoms, the marine species Crasepdostauros australis E. J. Cox and Nitzschia navis‐varingica Lundholm et Moestrup and the freshwater species Pinnularia viridis (Nitzsch) Ehrenberg. Contrary to previous studies, we show that this surface mucilage layer displays unique nanostructural features. In C. australis, tapping mode images revealed a soft mucilage layer encasing the silica cell wall, consisting of a smooth flat surface that was interrupted by regions with groove‐like indentations, whereas force measurements revealed the adhesive binding of polymer chains. The elastic responses of these polymer chains, as they were stretched during force measurements, were successfully fitted to the worm‐like chain model, indicating the stretching of mostly single macromolecules from which quantitative information was extracted. In P. viridis, tapping mode images of cells revealed a mucilage layer that had the appearance of densely packed spheres, whereas force measurements exhibited no adhesion. In N. navis‐varingica, tapping mode images of the outer surface of this cell in the girdle region revealed the absence of a mucilage layer, in contrast to the other two species. In addition to these topographic and adhesion studies, the first quantitative measurement of the elastic properties of microalgal extracellular polymeric substance is presented and reveals significant spatial variation in the C. australis and P. viridis mucilage layers. This study highlights the capacity of AFM in elucidating the topography and mechanical properties of hydrated microalgal extracellular polymeric substance on a nanoscale.
THE EFFECT OF PHOTON IRRADIANCE ON THE BEHAVIORAL ECOLOGY AND POTENTIAL NICHE SEPARATION OF FRESHWATER PHYTOPLANKTONIC FLAGELLATES1
Authors: Clegg Mark R. , Maberly Stephen C. , Jones Roger I.
Published: July 2003

Photoresponsive behavior in phytoplanktonic flagellates potentially controls depth regulation, vertical migration, and the accumulation of cells in preferred conditions and hence has major implications for photosynthesis, growth, and species competition. This study used microscale laboratory chambers with cell track analysis and mesoscale lake studies to investigate the responses of five phylogenetically contrasting freshwater flagellates to gradients of light. Laboratory results demonstrated that these species differed in their light preferences despite being grown at the same photon irradiance. Preferred photon irradiances were 20–120, 20, 65–120, 4–20, and>200 μmol photons·m−2·s−1, respectively, for Ceratium furcoides (Levander) Langhans, Chlamydomonas moewusii Gerloff, Dinobryon sertularia Ehrenberg, Euglena gracilis Klebs, and Plagioselmis nannoplanctica (Skuja) Novarino. Analysis of the response of individual cells showed that in all species, photoresponsive preference was the result of positive and negative phototaxis combined with step‐up and step‐down photophobic reactions. There was no evidence for photokinesis or cell memory. Only in C. furcoides did the preferred photon irradiance alter with growth conditions. In C. furcoides, D. sertularia, and P. nannoplanctica, irradiance preference matched the optimal irradiance for growth, whereas in the two remaining species a lower than optimal irradiance was preferred, suggesting that light may be used as an indicator of other ecological conditions. Mesoscale experiments in a lake demonstrated that the laboratory microscale measurements provide information relevant to understanding ecological distributions. Behavioral responses to light contribute to the delineation of vertical niche separation and provide a method for predicting the spatial and temporal distribution of flagellates.
PHYLOGENY OF PHAGOTROPHIC EUGLENIDS (EUGLENOZOA): A MOLECULAR APPROACH BASED ON CULTURE MATERIAL AND ENVIRONMENTAL SAMPLES1
Authors: Busse Ingo , Patterson David J. , Preisfeld Angelika
Published: July 2003

Molecular studies based on small subunit (SSU) rDNA sequences addressing euglenid phylogeny hitherto suffered from the lack of available data about phagotrophic species. To extend the taxon sampling, SSU rRNA genes from species of seven genera of phagotrophic euglenids were investigated. Sequence analyses revealed an increasing genetic diversity among euglenid SSU rDNA sequences compared with other well‐known eukaryotic groups, reflecting an equally broad diversity of morphological characters among euglenid phagotrophs. Phylogenetic inference using standard parsimony and likelihood approaches as well as Bayesian inference and spectral analyses revealed no clear support for euglenid monophyly. Among phagotrophs, monophyly of Petalomonas cantuscygni and Notosolenus ostium, both comprising simple ingestion apparatuses, is strongly supported. A moderately supported clade comprises phototrophic euglenids and primary osmotrophic euglenids together with phagotrophs, exhibiting a primarily flexible pellicle composed of numerous helically arranged strips and a complex ingestion apparatus with two supporting rods and four curved vanes. Comparison of molecular and morphological data is used to demonstrate the difficulties to formulate a hypothesis about how the ingestion apparatus evolved in this group.
PHYLOGENY OF THE DASYCLADALES (CHLOROPHYTA, ULVOPHYCEAE) BASED ON ANALYSES OF RUBISCO LARGE SUBUNIT (rbcL) GENE SEQUENCES1
Authors: Zechman Frederick W.
Published: July 2003

The phylogeny of the green algal Order Dasycladales was inferred by maximum parsimony and Bayesian analyses of chloroplast‐encodedrbcL sequence data. Bayesian analysis suggested that the tribe Acetabularieae is monophyletic but that some genera within the tribe, such asAcetabulariaLamouroux andPolyphysaLamouroux, are not. Bayesian analysis placedHalicoryneHarvey as the sister group of the Acetabularieae, a result consistent with limited fossil evidence and monophyly of the family Acetabulariaceae but was not supported by significant posterior probability. Bayesian analysis further suggested that the family Dasycladaceae is a paraphyletic assemblage at the base of the Dasycladales radiation, casting doubt on the current family‐level classification. The genusCymopoliaLamouroux was inferred to be the basal‐most dasycladalean genus, which is also consistent with limited fossil evidence. Unweighted parsimony analyses provided similar results but primarily differed by the sister relationship betweenHalicoryneLamouroux andBornetellaMunier‐Chalmas, thus supporting the monophyly of neither the families Acetabulariaceae nor Dasycladaceae. This result, however, was supported by low bootstrap values. Low transition‐to‐transversion ratios, potential loss of phylogenetic signal in third codon positions, and the 550 million year old Dasycladalean lineage suggest that dasycladrbcL sequences may be saturated due to deep time divergences. Such factors may have contributed to inaccurate reconstruction of phylogeny, particularly with respect to potential inconsistency of parsimony analyses. Regardless, strongly negative g1values were obtained in analyses including all codon positions, indicating the presence of considerable phylogenetic signal in dasycladrbcL sequence data. Morphological features relevant to the separation of taxa within the Dasycladales and the possible effects of extinction on phylogeny reconstruction are discussed relative to the inferred phylogenies.
MORPHOLOGICAL AND 16S rRNA GENE EVIDENCE FOR RECLASSIFICATION OF THE PARALYTIC SHELLFISH TOXIN PRODUCING APHANIZOMENON FLOS‐AQUAE LMECYA 31 AS APHANIZOMENON ISSATSCHENKOI (CYANOPHYCEAE)1
Authors: Li Renhui , Carmichael Wayne W. , Pereira Paulo
Published: July 2003

A taxonomic reevaluation of the paralytic shellfish toxin (saxitoxins) producing cyanobacterium Aphanizomenon flos‐aquae Ralfs ex Born. & Flah. LMECYA31 was done using morphology and 16S rRNA gene sequences. We found that strain LMECYA31 was incorrectly identified as Aph. flos‐aquae based on (a) lack of bundle formation in trichomes, (b) shape of terminal cells in the trichomes, (c) lower similarity (<97.5%) in the 16S rRNA gene sequences relative to those of Aph. flos‐aquae, and (d) comparison within a phylogenetic tree of 16S rRNA gene sequences. The shape of the terminal trichome cells and the shape and size of the vegetative cell, heterocyst, and akinete in strain LMECYA31 match characters of Aph. issatschenkoi (Ussachew) Proschkina‐Larvernko. 16S rRNA gene sequences and phylogenetic clusters constructed from 16S rRNA gene sequences support our conclusion that strain LMECYA31 should be Aph. issatschenkoi.
POLYPHYLETIC ORIGIN OF PARALLEL BASAL BODIES IN SWIMMING CELLS OF CHLOROPHYCEAN GREEN ALGAE (CHLOROPHYTA)1
Authors: Shoup Suzanne , Lewis Louise A.
Published: July 2003

The evolutionary affinities of Heterochlamydomonas Cox and Deason and Dictyochloris Vischer ex Starr were investigated using phylogenetic analyses of a combined data set of 18S and 28S rDNA sequences with those from 38 additional green algae. Previous ultrastructural studies have shown that motile cells of Heterochlamydomonas and Dictyochloris have an unusual flagellar apparatus organization in that the two flagella are of unequal length and the basal bodies are persistently parallel. Because of this similarity these taxa, along with Bracteacoccus Tereg, a third taxon with this same flagellar apparatus arrangement, are hypothesized to be closely related. We show, with maximum parsimony and Bayesian analyses, that the parallel basal bodies are not homologous in the three genera. Rather, Heterochlamydomonas is most closely related to Chlamydomonas baca in the clockwise flagellar apparatus clade, and Dictyochloris and Bracteacoccus are nested within the Sphaeropleales, which has the directly opposite flagellar absolute orientation. Surprisingly, Dictyochloris and Bracteacoccus are not supported as closest relatives. These relationships are supported by morphological features such as the presence or absence of a walled motile cell but not by the orientation of the basal bodies. In addition, our data are derived from multiple isolates of each study genera, and the analyses show that Heterochlamydomonas and Dictyochloris are each monophyletic.
REPRODUCTION AND SEXUALITY IN PFIESTERIA SHUMWAYAE (DINOPHYCEAE)1
Authors: Parrow Matthew W. , Burkholder JoAnn M.
Published: July 2003

Pfiesteria shumwayae is a heterotrophic dinoflagellate with a widespread distribution in temperate‐subtropical estuarine waters. In this study, five clonal isolates from the eastern coast of North America, one from New Zealand, and a mixed composite of clones were cultured in aquaria and fed live fish. Division, sexuality, and phagotrophic feeding on fish were studied by LM, SEM, and flow cytometry. The development of reproductive cysts isolated from aquaria was followed. Synchronously excysted flagellate populations were examined for sexuality and then for feeding behavior and reproduction when given larval fish. Reproductive cysts varied in size and underwent protoplast division(s), most commonly producing two to eight biflagellated offspring. Fusing gametes, resulting planozygotes, and nuclear cyclosis were documented as evidence of sexuality. Gametes emerged from cysts, and fusions were approximately isogamous. Resulting planozygotes had two longitudinal flagella and one transverse flagellum and apparently fed before encysting. Distinct and lengthy chromosome movements (nuclear cyclosis) occurred in presumed zygotic cysts before nuclear division(s). These cysts did not exhibit dormancy in growing cultures and produced two or four biflagellated offspring. Flagellated cells fed on surficial fish tissues and then encysted for reproduction. Stages indicating a completed sexual cycle (fusion, planozygotes, and nuclear cyclosis) were uncommon or absent in clonal cultures but were relatively abundant in the mixed clone culture. Self‐sterility factors apparently influenced sexuality. Starved populations formed quiescent cysts that released swimming cells when food was provided. Pfiesteria shumwayae was similar in reproduction and sexuality to closely related species.
Assessment of Acute Right Ventricular Dysfunction Induced by Right Coronary Artery Occlusion Using Echocardiographic Atrioventricular Plane Displacement
Authors: Shah Alpesh R. , Grodman Richard , Salazar Manuel F. , Rehman Najeeb U. , Coppola John , Braff Robert
Published: July 2003

Right ventricular (RV) systolic function analysis by echocardiography has traditionally required RV endocardial border definition with subsequent tracing and is often inaccurate or impossible in technically poor studies. The atrioventricular plane displacement (AVPD) method attempts to use the descent of the tricuspid annular ring, a reflection of the longitudinal shortening of the right ventricle, as a surrogate marker for RV systolic function. We hypothesized that RV ischemia induced during right coronary artery occlusion proximal to the major right ventricular branches would result in severe right ventricular systolic dysfunction detectable by the AVPD method. During this pilot study, seven patients undergoing elective proximal RCA angioplasty had echocardiographic measurement of RV AVPD performed at baseline (i.e., immediately prior to RCA balloon inflation), during the last 30 seconds of first RCA balloon inflation, and at 1 minute after balloon deflation (recovery). Lateral and medial RV AVPD were significantly reduced from baseline values during intracoronary balloon inflation. (Lateral: 2.45 cm ± 0.22 vs 1.77 cm ± 0.13, P < 0.001; medial: 1.46 cm ± 0.37 vs 1.28 cm ± 0.32, P < 0.05). Additionally, lateral and medial RV AVPD significantly returned towards baseline values during recovery. (Lateral: 2.39 cm ± 0.20, P < 0.001; medial: 1.58 cm ± 0.27, P = 0.01). At baseline, all lateral RV AVPD values were > 2.0 cm, whereas during balloon inflation all were < 2.0 cm. No such clear distinction was found in medial RV AVPD values. Proximal RCA angioplasty is associated with a significant reduction in lateral and medial RV AVPD. Thus RV AVPD may serve as a marker for RV systolic dysfunction.
Assessment of Left Ventricular Regional Wall Motion by Color Kinesis Technique: Comparison with Angiographic Findings
Authors: Vermes Emmanuelle , Guyon Philippe , Weingrod Michel , Otmani Akli , Soussana Carl , Halphen Christine , Leroy Gérard , Haïat Robert
Published: July 2003

The analysis of segmental wall motion using two‐dimensional (2‐D) echocardiography is subjective with high interobserver variability. Color kinesis is a new technique providing a color‐encoded map of endocardial motion. We evaluated the accuracy of color kinesis and 2‐D for assessment of regional asynergy compared with left ventricular angiography as a reference method. Fifteen patients admitted for myocardial infarction were studied by echocardiography the day before left ventricular angiography. The left ventricle was divided into seven segments. Each segment was classified by two independent observers as normal or abnormal in 2‐D and color kinesis. Accuracy of color kinesis and 2‐D was evaluated and compared to left ventricular angiography. Color kinesis is significantly superior to 2‐D for all seven segments (mean 0.80/0.68, P = 0.05), except for the septum (0.67/0.60, P = NS). Interobserver variability studied by chi‐square statistic is lower with color kinesis (0.70) than with 2‐D (0.57). We conclude that these data suggest that color kinesis is a useful method for assessing systolic wall motion in all segments, except the septum and for improving the accuracy of segmental ventricular function and interobserver variability.
Power Doppler Imaging as a Basis for Automated Endocardial Border Detection During Left Ventricular Contrast Enhancement
Authors: Mor‐Avi Victor , Bednarz James , Weinert Lynn , Sugeng Lissa , Lang Roberto M.
Published: July 2003

Echocardiographic evaluation of left ventricular (LV) systolic function relies on endocardial visualization, which can be improved when necessary using contrast enhancement. However, there is no method to automatically detect the endocardial boundary from contrast‐enhanced images. We hypothesized that this could be achieved using harmonic power Doppler imaging. Twenty‐two patients were studied in two protocols: (1) 11 patients with poorly visualized endocardium (> 3 contiguous segments not visualized) and (2) 11 consecutive patients referred for dobutamine stress echocardiography who were studied at rest and at peak dobutamine infusion. Patients were imaged in the apical four‐chamber view using harmonic power Doppler mode (HP SONOS 5500) during LV contrast enhancement (Optison or Definity DMP115). Digital images were analyzed using custom software designed to automatically extract the endocardial boundary from power Doppler color overlays. LV cavity area was automatically measured frame‐by‐frame throughout the cardiac cycle, and fractional area change calculated and compared with those obtained by manually tracing the endocardial boundary in end‐systolic and end‐diastolic gray scale images. Successful border detection and tracking throughout the cardiac cycle was possible in 9 of 11 patients with poor endocardial definition and in 10 of 11 unselected patients undergoing dobutamine stress testing. Fractional area change obtained from power Doppler images correlated well with manually traced area changes (r = 0.82 and r = 0.97, in protocols 1 and 2, respectively). Harmonic power Doppler imaging with contrast may provide a simple method for semi‐automated border detection and thus facilitate the objective evaluation of LV function both at rest and under conditions of stress testing. This methodology may prove to be particularly useful in patients with poorly visualized endocardium.
Tissue Doppler Imaging: A New Technique for Assessment of Pseudonormalization of the Mitral Inflow Pattern
Authors: Bruch Christian , Schmermund Axel , Bartel Thomas , Schaar Johannes , Erbel Raimund
Published: July 2003

Left ventricular diastolic dysfunction (LVDD) is a frequent cause of heart failure. Doppler echocardiography has become the method of choice for the noninvasive evaluation of LVDD. However, pseudonormalization (PN) of the mitral inflow often presents a diagnostic challenge in clinical practice. In this setting, we sought to define the role of tissue Doppler imaging (TDI) of the septal mitral annulus. Echocardiography was performed in 36 consecutive subjects (age 59 ± 10 years). Eighteen of these had diagnosed coronary artery disease (CAD) with recent onset of symptoms (within 3 months), 18 had clinical suspicion of CAD, and 15 had symptoms of heart failure (New York Heart Association [NYHA] Class 2.4 ± 0.5). The mitral inflow profile (E, A, E/A) was measured by pulsed Doppler, and the deceleration time (DT) and the isovolumic relaxation time (IVRT) were calculated. Peak diastolic velocities of the septal mitral annulus (ET, AT, ET/AT) and the time interval from Q in the ECG to the onset of ET were derived from pulsed TDI. Left heart catheterization was performed for direct measurement of left ventricular end‐diastolic pressure (LVEDP). PN defined by an E/A ratio > 1 and an LVEDP ≥ 16 mmHg was found in nine patients. All patients with PN had symptoms of heart failure (NYHA Class 2.8 ± 0.5). Patients with and without PN did not differ with respect to the E/A ratio (1.29 ± 0.44 vs 1.16 ± 0.23, P = ns), DT (182 ± 38 msec vs 205 ± 42 msec, P = ns), and IVRT (88 ± 24 msec vs 92 ± 18 msec, P = ns). In the group with PN, a significant reduction of ET (5.6 ± 1.8 cm/sec vs 8.8 ± 2.9 cm/sec, P < 0.05) and ET/AT (0.5 ± 0.16 vs 0.82 ± 0.37, P < 0.05) was detected. In the PN group, the Q‐ET interval was prolonged (404 ± 48 msec vs 346 ± 50 msec, P < 0.05). Receiver operating characteristic curve analysis for ETyielded an area under the curve of 0.78 ± 0.06 (P = 0.034) for separating patients with versus without PN. When the combination of ET < 7 cm/sec and ET/AT < 1 was used as cutpoint, PN could be identified with a sensitivity of 83% and a specificity of 79%. There was no significant relation between LVEDP and either ET (r = 0.32, P > 0.2) or the Q‐ET interval (r = 0.14, P > 0.5). In conclusion, ET and the Q‐ET interval appear to be useful parameters for assessing LV diastolic dysfunction in symptomatic patients with a pseudonormal mitral inflow pattern and elevated filling pressures.
Left Ventricular Apical Thrombus and Myocardial Viability: A Dobutamine Stress Echocardiographic Study
Authors: Cusick David A. , Bonow Robert O. , Chaudhry Farooq A.
Published: July 2003

The objective of this article was to determine whether the presence of left ventricular apical thrombus is a marker of nonviable myocardium. Reduced coronary blood flow secondary to atherosclerosis may result in chronic reversible left ventricular wall‐motion abnormalities. Severe regional abnormalities also predispose to formation of left ventricular thrombus. The relationship between left ventricular apical thrombus and myocardial viability has not been previously described. Eighty patients with coronary artery disease and chronic left ventricular dysfunction were studied by dobutamine stress echocardiography. Left ventricular apical thrombus was identified using echocardiographic criteria. Wall‐motion analysis was performed using a standard 16‐segment model and ejection fraction was calculated. As a result, 48 patients (60%) had definite or highly suspicious findings for left ventricular thrombus (group 1), and 32 patients (40%) had no thrombus (group 2). Group 1 had significantly higher composite (54.0 ± 5.8 vs 43.3 ± 6.4) and apical (6.0 ± 2.7 vs 12.4 ± 3.4) wall‐motion scores compared to those in group 2 (P = 0.01). Thirty‐two patients (67%) in group 1 demonstrated no contractile reserve in the apical segments, consistent with lack of viability, versus eight patients (25%) in group 2 (P = 0.0003). The number of viable apical segments per patient was significantly less in group 1 (0.7 ± 1.2) versus group 2 (1.8 ± 1.3) (P = 0.01). Left ventricular apical thrombus is more likely to be present when there is absence of myocardial viability in the corresponding segments.
Comparison of Echocardiographic Markers of Embolism in Atrial Flutter and Fibrillation: Frequency of Protruding Atherosclerotic Plaques in the Thoracic Aorta
Authors: Rozenberg Valérie , Boccara Franck , Benhalima Bouziane , Lamisse Nathalie , Buyukoglu Bülent , Cohen Ariel
Published: July 2003

The potential additional embolic risk of protruding aortic plaques ≥ 4 mm and left atrial abnormalities such as thrombus, spontaneous echocardiographic contrast (SEC), low left atrial appendage velocity, recently has been shown in patients with atrial fibrillation (AF). However, the presence and potential role of transesophageal echocardiographic (TEE)‐detected protruding aortic plaques ≥ 4 mm have not been systematically evaluated in patients with atrial flutter. Among 2493 patients evaluated by TEE, 271 consecutive patients with atrial flutter (n = 41) and AF (n = 230) ≥ 2 days duration were included in the study. Clinical and echocardiographic characteristics in consecutive patients with atrial flutter were compared to those in patients with AF, especially atrial morphology and function and atherosclerotic disease of the thoracic aorta. Clinical characteristics of patients with atrial flutter and AF were similar with regard to age (68 ± 13 and 67 ± 12, P = 0.628), sex ratio (men, 66% and 54%, P = 0.212), and previous embolic events (5% and 15%, P = 0.126), respectively. The frequency of protruding atherosclerotic plaques ≥ 4 mm (12% and 11%, P = 0.919) and SEC (15% and 14%, P = 0.847) in the thoracic aorta was similar in patients with atrial flutter and AF. Left atrial appendage area was smaller (3.1 ± 0.7 and 6.0 ± 3.0 cm2, P = 0.001), left atrial appendage SEC was less frequent (17% and 37%, P = 0.024), and left atrial appendage emptying velocity was higher (47 ± 10 and 30 ± 10 cm/s, P = 0.030) in patients with atrial flutter as compared to those with AF. There was no difference between the two groups regarding left ventricular fractional shortening (30 ± 10% and 33 ± 13%, P = 0.630), rheumatic valvular disease (5% and 12%, P = 0.301), left atrial diameter (43 ± 7 and 45 ± 8 mm, P = 0.134), right atrial area (16 ± 4 and 17 ± 6 cm2, P = 0.384), left atrial SEC (39% and 53%, P = 0.124), or atrial thrombus (2% and 3%, P = 0.888) respectively. Our results point to the high prevalence of protruding atherosclerotic plaques in the thoracic aorta in patients with atrial flutter.
High Intensity Focused Ultrasound Effect on Cardiac Tissues: Potential for Clinical Application
Authors: Lee Lisa A. , Simon Claudio , Bove Edward L. , Mosca Ralph S. , Ebbini Emad S. , Abrams Gerald D. , Ludomirsky Achiau
Published: July 2003

High intensity focused ultrasound (HIFU) is an evolving technology with potential therapeutic applications. Utilizing frequencies of 500 kHz to 10 MHz, HIFU causes localized hyperthermia at predictable depths without injuring intervening tissue. Applications in neurosurgery, urology, oncology and, more recently, cardiology for selective cardiac conduction tissue ablation have been promising. A ‘noninvasive’ technique for causing localized tissue damage to relieve hemodynamic and life‐threatening obstruction in patients with congenital cardiac anomalies could replace more invasive procedures. We, therefore, investigated the ability of HIFU to create lesions in mammalian cardiac tissues ex vivo. Porcine valve leaflet, canine pericardium, human newborn atrial septum, and right atrial appendage were studied. Specimens were mounted and immersed in a water bath at room temperature. Using a 1‐MHz phased array transducer, ultrasound energy was applied with an acoustic intensity of 1630 W/cm2 or 2547 W/cm2 until a visible defect was created (duration 3 to 25 sec). Macroscopic and microscopic examination demonstrated precise defects ranging from 3 to 4 mm in diameter. No damage was identified to the surrounding tissues. Our study concluded that HIFU can create precise defects in different cardiac tissue without damage to the surrounding tissue. Further investigation is needed to assess potential clinical uses of this technology.
Acute Myocarditis and Left Ventricular “Hypertrophy”
Authors: Sagrera María Riera , Sala Miguel Fiol , Bárcena Jon Pérez , Garcia Jaume Bergadà , Cañellas Catalina Forteza , Juvé Jordi Ibáñez
Published: July 2003

Echocardiographic abnormalities of myocarditis are polymorphous and nonspecific. The presence of increased ventricular wall thickness, typically transient, is an infrequent finding in myocarditis that can correspond to an improvement in the clinical status of the patient and the ejection fraction. We report the case of a patient with acute myocarditis and the echocardiographic abnormalities observed during the course of his myocarditis: transient left ventricular “hypertrophy” associated with improvement of the left ventricular function.
Carcinoid Heart Disease in Association with a Primary Ovarian Carcinoid Tumor: Diagnostic Role of Echocardiography
Authors: Franko David M. , Berger Marvin
Published: July 2003

We describe a patient with carcinoid heart disease secondary to a primary ovarian carcinoid tumor who initially presented with unexplained right‐sided heart failure. The patient did not exhibit any of the typical clinical manifestations of the carcinoid syndrome. Echocardiography demonstrated typical features of carcinoid heart disease and played an important role in the detection and management of a condition that was previously unrecognized.
Diagnostic and Prognostic Value of Myocardial Perfusion Imaging in Patients with Known or Suspected Stable Coronary Artery Disease
Authors: Amanullah Aman M.
Published: July 2003

Coronary artery disease is the leading cause of complications and death in the United States and other Western countries, and stress myocardial perfusion study is an important component of the clinical evaluation, stratification, and management. This imaging technique is a well‐established modality and has been widely used for the past three decades. New quantitative techniques for the assessment of ventricular function using quantitative gated single‐photon emission computed tomography in addition to myocardial perfusion will potentially enhance the role of nuclear cardiology in the management of these patients. This review summarizes the current knowledge of the diagnostic and prognostic uses of stress myocardial perfusion imaging using exercise and pharmacological stress in patients with stable coronary artery disease.
Nuclear Cardiology in the Evaluation of Acute Chest Pain in the Emergency Department
Authors: Abbott Brian G. , Jain Diwakar
Published: July 2003

Only a minority of patients presenting to the emergency department (ED) with acute chest pain will eventually be diagnosed with an acute coronary syndrome. The majority will have an electrocardiogram that is normal or nondiagnostic for acute myocardial ischemia or infarction. Typically, these patients are admitted to exclude myocardial infarction despite a very low incidence of coronary artery disease. However, missed myocardial infarctions in patients who are inadvertently sent home from the ED have significant adverse outcomes and associated legal consequences. This leads to a liberal policy to admit patients with chest pain, presenting a substantial burden in terms of cost and resources. Many centers have developed chest pain centers, using a wide range of diagnostic modalities to deal with this dilemma. We discuss the methods currently available to exclude myocardial ischemia and infarction in the ED, focusing on the use of myocardial perfusion imaging as both an adjunct and an alternative to routine testing. We review the available literature centering on the ED evaluation of acute chest pain and then propose an algorithm for the practical use of nuclear cardiology in this setting.
Radionuclide Imaging for the Assessment of Myocardial Viability in Chronic LV Dysfunction
Authors: Al‐Khouri Fareed , Narula Jagat
Published: July 2003

Clinical decision making for the selection of patients with coronary artery disease and depressed left ventricular (LV) function for coronary revascularization is very critical but at times difficult. There is strong evidence of an increased event rate (myocardial infarction, death, unstable angina) in one fourth of patients with viable myocardium who are treated medically compared with only one sixteenth after revascularization. Documentation of the presence of viable myocardium best allows identification of patients who are most likely to benefit from coronary revascularization as evident by postoperative improvement in LV systolic function, exercise capacity, quality of life, or survival. On the other hand, identifying patients who would not demonstrate significant improvement is equally important in view of the high morbidity and mortality rates associated with surgery in such patients. Noninvasive imaging to determine the presence and extent of viable myocardium has become an important component of the assessment of patients with coronary artery disease and depressed LV function. About 40% of such patients have the potential for significant improvement after successful surgical revascularization. This review summarizes the role of radionuclide myocardial perfusion imaging for the assessment of viable myocardium.
In Vitro Validation of a New Approach for Quantitating Regurgitations Using Proximal Isovelocity Surface Area
Authors: Delouche A. , Augusseau M.‐P. , Dumée Ph. , Delouche Ph. , Diebold Benoit
Published: July 2003

The present work has been designed to validate the calculation of the effective regurgitant orifice (ERO) area with the use of a new formula that takes into account the velocity profile (Vr vs r) and that is insensitive to errors in the determination of the position of the orifice. Assuming a hemispheric model, ERO = 2πr2· Vr/Vo (with Vo= velocity at the orifice) and (Vo/Vr)0.5= (2π/ERO)0.5r. Thus, the slope of the corresponding linear regression allows ERO to be calculated as: ERO = 2π/slope2. This approach was tested in vitro in pulsatile conditions on circular, conical, and slit‐like orifices. The calculated ERO was compared with the actual jet cross sectional area derived from the transverse velocity profile at the jet origin. For the purpose of comparison, the “classical” ERO was calculated for all the configurations, angulations, and threshold velocities. The relationship between (Vo/Vr)0.5 was linear (r > 0.98) over a wide range of velocities. The nonhemispheric components were found to modify the constant and not the slope. The mean variation of the calculated ERO was 6.5%. The correlation between the calculated and the actual ERO was very close (>0.97) with slope equal to 0.96. By comparison with the new method, the classical formula gave an underestimation of the ERO that dramatically increased when studying the flow closer to the orifice or in the case of error on the measurement of r. In conclusion, a method using velocity profiles instead of isolated values improves the accuracy of the proximal isovelocity surface area (PISA) method for measuring the ERO.
Echocardiographic Imaging of Stentless Aortic Valve Prostheses
Authors: Baur Leo H.B. , Peels Kathinka , Braun Jerry , Kappetein Arie‐Pieter , Bootsma Marianne , Van Der Ploeg Arianne , Sieders Alard , Hazekamp Mark , Van Der Wall Ernst E. , Huysmans Hans A.
Published: July 2003

Homografts and stentless xenografts are increasingly used in aortic valve surgery. Echocardiography technicians and cardiologists have to know what they will find when performing an echo‐Doppler examination in patients who received a stentless valve. We therefore evaluated echocardiographic images of 74 patients who received a Freestyle stentless bioprosthesis with three techniques and a follow‐up of 2 years in two high‐volume hospitals. Of the patients studied, 81% were operated using the subcoronary technique, 12% using the root‐inclusion technique, and 7% using the full‐root technique. Results: Transvalvular gradients across the stentless valves were low: 8.0 mmHg when implanted with the subcoronary technique, 8.2 ± 5.1 mmHg using the root‐inclusion technique, and 6.5 mmHg using the full‐root technique. Trivial aortic insufficiency (grade 1) was observed in 10.7% of the patients (8.9% for the subcoronary technique, 13% for the root‐inclusion technique, and 0% for the full‐root technique). When the bioprosthesis was implanted using the subcoronary technique or the root‐inclusion technique, the prosthesis was placed inside the recipient aortic root. Using these techniques, a lumen between the double layer of the xenograft and the aortic wall could be observed. With the root‐replacement technique, the porcine root became the most proximal part of the ascending aorta. As the native aortic wall was removed, in most cases, no double lumen could be observed with imaging of the ascending aorta.
Reproducibility of Left Ventricular Measurements with Acoustic Quantification: The Influence of Training
Authors: Vandenberg Byron F. , Lindower Paul D. , Lewis Jane , Burns Trudy L.
Published: July 2003

Acoustic quantification (AQ) of two‐dimensional (2‐D) echocardiograms provides online estimation of left ventricular (LV) size and function. However, edge detection with AQ is influenced by gain settings and is therefore operator dependent. Our purpose was to compare AQ and conventional 2‐D echo measurements of LV size and function obtained by different operators and to evaluate the influence of training on these measurements. A cardiac sonographer without previous experience with the AQ system was trained by an experienced operator. Twenty‐two normal males (age, 28 ± 4 years) participated in the study. Images were recorded with conventional 2‐D and AQ echo from the short‐axis and apical four‐chamber views. During the initial training period, five subjects were imaged by the sonographer under the supervision of the trainer. At the initial study session, 12 subjects were imaged independently by the two operators. Following a second training period with five different subjects, the same initial 12 subjects were again imaged at a second study session. LV cavity areas were traced from the conventional 2‐D echocardiograms and measured from the AQ waveforms at end‐diastole and end‐systole. Volumes were calculated using the single‐plane area‐length method. Ejection fraction (EF) was calculated from volumes. Reproducibility was determined by comparing the variability of AQ and conventional 2‐D echo measurements obtained at the two sessions. A second training session reduced the operator variability only of the short‐axis end‐diastolic area measurement (17 ± 11% vs 6 ± 5%, P < 0.025). We conclude that a single training session may be adequate for the reproducible estimation of ventricular volumes with the AQ method.
A Comparison of Regional Myocardial Velocity Information Derived by Pulsed and Color Doppler Techniques: An In Vitro and In Vivo Study
Authors: Kukulski Tomasz , Voigt Jens Uwe , Wilkenshoff Ursula M. , Strotmann Jorg M. , Wranne Bengt , Hatle Liv , Sutherland George R.
Published: July 2003

The objective was to compare velocity information derived from either a tissue mimicking phantom or normal contracting myocardium by both pulsed wave and color Doppler myocardial imaging (PWDMI and CDMI). Both CDMI and PWDMI allow quantitative assessment of regional myocardial contraction and relaxation velocities, but their potential clinical applications have not yet been investigated. Moreover, no information is available as to whether they can be used interchangeably for regional velocity assessment. For the in vitro study, a rotating, circular‐shaped, tissue‐mimicking sponge driven by a motor at speeds of 15, 30, 60, 90 rpm was used to derive velocity data from the same eight points of interest by using PWDMI or CDMI techniques. For the in vivo study, 25 normal subjects were examined at rest using parasternal and apical approaches. Velocity profiles were derived from the same 26 areas of interest (18 left ventricular segments, 3 right ventricular segments, and 5 measurement points for the tricuspid and mitral annuli) for each technique. Peak maximal velocities were detected by PWDMI and peak mean velocities were measured using CDMI. The results of the in vitro study phantom showed excellent correlation (r = 0.99, P < 0.001) and satisfactory agreement (0.04 cm/sec; 3.3 cm/sec) between both Doppler techniques. PWDMI velocities were higher than CDMI velocities by up to 20% and overestimated the real velocity value (0.37 ± 0.29 cm/sec) while CDMI underestimated predicted velocity by 1.35 ± 0.36 cm/sec. Good correlation (r = 0.87, P < 0.001), but poor agreement (−2.1 cm/sec; 5.4 cm/sec) was shown in vivo for all segments with regard to peak systolic and diastolic velocities. Both Doppler techniques cannot be used interchangeably for comparing peak velocities in the clinical situation. However, with adequate temporal resolution, they can be used interchangeably for velocity profile recording and for timing of events.
Left Ventricular Inflow Normal or Pseudonormal. A New Echocardiographic Method: Diastolic Change of Left Atrial Diameter
Authors: Kurtoglu Nuri , Akdemir Ramazan , Yuce Murat , Basaran Yelda , Dindar Ismet
Published: July 2003

Mitral flow Doppler study has been used to evaluate left ventricle (LV) diastolic function. Through its use, greater A wave than E wave, pseudonormal pattern, and restrictive pattern were observed progressively in patients with more LV diastolic dysfunction. Differentiation of normal or pseudonormal mitral flow is very important. In this study, left atrium (LA) diameter change during diastole was used as a new method for the differentiation of normal and pseudonormal mitral flow. Method: Sixty‐eight patients (30 men, 38 women; mean age 53 ± 13 years) with echocardiographically determined diastolic dysfunction and 60 healthy volunteers (36 men, 24 women; mean age 49 ± 12 years) were included in the study. Mitral flow E/A ratio, isovolumetric relaxation time (IVRT), and deceleration time (DT) of E wave were used for determination of the diastolic dysfunction. Thirty of 68 diastolic dysfunction patients had A>E wave, 20 had pseudonormal mitral flow pattern, and 18 had restrictive mitral flow pattern. Left parasternal long‐axis echocardiographic window was used for the measurement of LA diameter. Left atrium emptying fraction (LAEF) was defined as ratio of end‐diastolic LA diameter to end‐systolic diameter. Results: LAEF was found 0.69 ± 0.01 (mean ± SE) in the control group, 0.76 ± 0.01 in the A>E group (P < 0.05, control vs A>E group), 0.83 ± 0.05 in the pseudonormal pattern group (P < 0.05, control vs pseudonormal pattern group), and 0.87 ± 0.01 in the restrictive pattern group (P < 0.001, control vs restrictive pattern group). Conclusion: (1) LV diastolic dysfunction reduces the filling of LA content to the LV during diastole; (2) LA diameter changes during diastole as a new and practical method for the differentiation of the normal‐pseudonormal mitral flow pattern.
Restrictive Left Ventricular Filling Pattern After Myocardial Infarction: Significance of Concomitant Preserved Systolic Function
Authors: Burgess Malcolm I. , Atkinson Paul , Ray Simon G.
Published: July 2003

Restrictive left ventricular (LV) filling identifies a high risk subgroup, following myocardial infarction (MI). The extent and significance of systolic dysfunction in this group is not clear. The aim of our study was to determine the incidence and extent of systolic dysfunction in patients with restrictive filling and nonrestrictive filling examining the prognostic implications. Doppler parameters of LV diastolic function were measured in 102 post‐MI subjects within 4 days. Restrictive filling was defined as the presence of E:A ratio > 2 or E:A ratio 1–2 with MDT ≤ 140 msec. Follow‐up was to a median of 11 months. Restrictive filling (group A) was found in 19 (19%) of 102 patients. Patients with this pattern were more likely to have systolic dysfunction than those without (group B); 63% and 35%, respectively, P = 0.024. Eight (42%) of 19 patients in group A had relatively preserved systolic function. At 11 months 14 patients had developed heart failure (HF), 6 in group A (32%) and 8 in group B (10%), P = 0.012. There were two deaths (11%) in group A and 7 (8%) in group B, P = ns. Seven (88%) of 8 patients in group A with relatively preserved systolic function were alive and free of heart failure at follow‐up compared to 4 of 11 patients (36%) in group A with systolic dysfunction (P = 0.026). Restrictive filling can be associated with relatively preserved systolic function after MI and these patients have a relatively good outcome. Patients with restrictive filling post‐MI are a heterogenous group emphasizing the evaluation of both systolic and diastolic function.
Determination of Left Ventricular Mass by Real‐Time Three‐Dimensional Echocardiography: In Vitro Validation
Authors: Takuma Shin , Cabreriza Santos E. , Sciacca Robert , Di Tullio Marco R. , Spotnitz Henry M. , Homma Shunichi
Published: July 2003

Twenty‐one explanted fixed hearts (14 dogs and 7 pigs) were examined to validate newly developed real‐time three‐dimensional (RT3D) echocardiography for measurement of left ventricular (LV) mass in vitro and to compare its accuracy and variability with those of conventional echocardiographic measurements. There was an excellent correlation and high degree of agreement for the determination of LV mass between RT3D echocardiography and true mass measurement (r = 0.98; standard error of the estimate [SEE]= 7.3 g; absolute difference [AD]= 2.8 g; y = 1.00 x −4.0, interobserver variability; 5.0%). The conventional echocardiographic methods yielded weaker correlations, larger standard errors, and interobserver variability (area‐length method: r = 0.90; SEE = 13.3 g; AD = 13.2 g; 13.3%/ truncated ellipsoid method: r = 0.91; SEE = 14.7 g; AD = 10.5 g; 7.9%/ M‐mode: r = 0.91; SEE = 16.2 g; AD = 9.4 g; 15.3%). Determination of LV mass by RT3D echocardiography has a high degree of accuracy and is superior to conventional one‐ and two‐dimensional echocardiographic methods.