bluuebunny/crossref_metadata_2025 huggingface dataset:
Draw ratio enhancement in nonisothermal melt spinning
Authors: Suman Balram , Kumar Satish
Published: February 2009

Nonisothermal melt spinning of materials having a step‐like viscosity variation with temperature is studied in this work. A set of nonlinear equations is used to describe the fiber behavior and to obtain the draw ratio, the square of the ratio of the fiber diameter at the entrance to that at the exit of the fiber‐spinning device. The fluid‐flow equation is based on a slender‐jet approximation, and external heating and cooling have been accounted for with a one‐dimensional model in order to obtain the fiber temperature and viscosity along the fiber length. The model is similar to that used by Wylie et al. (J Fluid Mech. 2007;570:1–16) but accounts for inertia, shear stress at the fiber surface, surface tension, gravity, cooling, and larger heating rates. Steady‐state analysis reveals that the draw ratio increases with an increase in the pulling force, passes through a maximum, and then starts increasing again, resulting in three possible pulling forces for the same draw ratio. However, linear stability analysis reveals that depending on the strength of heating and/or cooling, at most two of the steady states are stable. The stability analysis also predicts complicated oscillatory and nonoscillatory dynamical behavior as the pulling force varies. Nonlinear simulations reveal that an unstable system always tends to limit‐cycle behavior. Systems predicted as stable by the linear stability analysis are also stable for large‐amplitude perturbations. External heating is found to dramatically enhance the draw ratio of the melt‐spinning process. The addition of a cooling section suppresses the draw ratio, but this can be compensated for with a higher heating strength. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Terephthalic acid synthesis at higher concentrations in high‐temperature liquid water. 1. Effect of oxygen feed method
Authors: Osada Mitsumasa , Savage Phillip E.
Published: February 2009

We conducted terephthalic acid (TPA) synthesis from p‐xylene in high‐temperature liquid water (HTW) at 300°C. The p‐xylene concentration at the reaction condition was 0.2 mol L−1, which is the highest to date in research that achieved at least 80 mol % yields of TPA in HTW. Pure oxygen gas was the oxidant. Increasing the MnBr2 catalyst concentration increased the rate of TPA formation only slightly. In contrast, whether oxygen was fed in small, quick, discrete bursts, or fed continuously significantly affected the p‐xylene conversion and the TPA selectivity. Adding oxygen in quick bursts and small increments led to high selectivities (>90 mol %) of TPA. Continuous addition of oxygen failed to do so. In addition to identifying the sensitivity of this synthesis to the oxygen feed method, these results also demonstrate the feasibility of HTW for TPA synthesis at higher concentrations, and hence high TPA production per unit reactor volume. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Efficient separation of enantiomers by preferential crystallization in two coupled vessels
Authors: Elsner Martin Peter , Ziomek Grzegorz , Seidel‐Morgenstern Andreas
Published: February 2009

The focus of this work is to study the enantioseparation of conglomerate forming systems using an innovative configuration for preferential crystallization. Two batch crystallizers are coupled by an exchange of their liquid phases. In each vessel one of the two enantiomers is seeded initially and crystallizes subsequently. Compared with conventional single batch crystallization the exchange of the crystal free liquid phases between two crystallizers leads to an increase of the concentrations of the preferred enantiomers and therefore to an increase of the driving forces for the crystallization. This enhances the productivity of the process compared with the conventional operation. © 2009 American Institute of Chemical Engineers AIChE J, 2009
SPG11 mutations cause Kjellin syndrome, a hereditary spastic paraplegia with thin corpus callosum and central retinal degeneration
Authors: Örlén Hanna , Melberg Atle , Raininko Raili , Kumlien Eva , Entesarian Miriam , Söderberg Per , Påhlman Magnus , Darin Niklas , Kyllerman Mårten , Holmberg Eva , Engler Henry , Eriksson Urban , Dahl Niklas
Published: February 2009

Autosomal recessive hereditary spastic paraplegia (ARHSP) with thin corpus callosum (TCC) is genetically heterogenous and approximately 35% of patients carry mutations in either of the SPG11 or SPG15 genes. Disease onset is during the first three decades of life with spastic paraplegia and mental impairment. Peripheral neuropathy and amyotrophy may occur. Kjellin syndrome is characterized by central retinal degeneration in addition to ARHSP‐TCC and the disease is associated with mutations in the SPG15 gene. We identified five patients in four unrelated kindreds with spastic paraplegia and mental impairment. Magnetic resonance imaging revealed TCC, atrophy elsewhere in the brain and increased T2 signal intensity in the periventricular white matter. Probands from the four kindreds were screened for mutations in the SPG11 gene. All patients were found homozygous or compound heterozygous for truncating SPG11 mutations of which four are reported for the first time. Ophthalmological investigations revealed that the four index cases have central retinal degeneration consistent with Kjellin syndrome. PET examinations with N‐[11C‐methyl]‐L‐deuterodeprenyl (DED) and fluor‐18 2‐fluorodeoxyglucose (FDG) were performed in two patients with Kjellin syndrome. We observed a reduced glucose uptake in the thalami, anterior cingulum, and sensorimotor cortex indicating neuronal loss, and an increased DED binding in the thalami and pons which suggests astrogliosis. From our results we extend the SPG11 associated phenotype to comprise also Kjellin syndrome, previously found to be associated with mutations in the SPG15 gene. We anticipate that degeneration of the central retina is a common and previously unrecognized feature in SPG11 related disease. © 2009 Wiley‐Liss, Inc.
Association study of CREB1 with Major Depressive Disorder and related phenotypes
Authors: Hettema John M. , An Seon‐Sook , van den Oord Edwin J.C.G. , Neale Michael C. , Kendler Kenneth S. , Chen Xiangning
Published: February 2009

Cyclic AMP response element binding protein (CREB) has been implicated in behavioral models of anxiety and depression, antidepressant response in humans, and suicide. One group reported a female‐specific association of the CREB1 gene in early‐onset Major Depressive Disorder (MDD), while another found no evidence of association with this phenotype. In this study, we sought to examine the evidence for association of the CREB1 gene to MDD and related phenotypes. We used multivariate structural equation modeling to identify and select twin pairs that scored at the extremes of a latent genetic risk factor shared by MDD, neuroticism, and several anxiety disorders from the Virginia Twin Registry. Using one member from each of these pairs, the resulting sample of 589 cases (including 473 subjects with lifetime MDD) and 539 controls were entered into a 2‐stage association study in which genetic markers were screened in stage 1, the positive results of which were tested for replication in stage 2. Eight SNP markers selected to capture the major allelic variation across the haplotype block containing CREB1 were analyzed for differences between cases and controls. Several markers showed criterion differences between cases and controls in the stage 1 sample with some evidence of sex specific effects. However, none of these markers were significant in stage 2 in either sex individually or combined. Our data suggests that common variations in the CREB1 gene do not appear to increase susceptibility for MDD or related phenotypes. © 2009 Wiley‐Liss, Inc.
First description of the surgical anatomy of the cynomolgus monkey liver
Authors: Vons Corinne , Beaudoin Sylvie , Helmy Nada , Dagher Ibrahim , Weber Anne , Franco Dominique
Published: February 2009

No detailed description of nonhuman primate liver anatomy has been reported and little is known about the similarity between such livers and human liver. The cynomolgus monkey (Macaca fascicularis) was used to establish a preclinical model of genetically modified hepatocytes auto transplantation. Here, we report information gleaned from careful observation and notes obtained from 59 female cynomolgus monkeys undergoing 44 anatomical hepatic resections, 12 main portal vein division dissections and selective branch ligations, and 46 portographies. Additionally, three anatomical liver dissections after total resection at autopsy were performed and served to confirm peroperative observations and for photography to provide illustrations. Our results indicate that the cynomolgus monkey liver has four lobes: the median (the largest), the right and left lateral, and the caudate lobes. In 60% (N=20) of individuals the portal bifurcates into right and left portal veins, in the remaining 40% (N=14) the portal vein trifurcates into right anterior, right posterior, and left portal veins. The anatomy and branching pattern of the hepatic artery and bile ducts closely follow those of the portal branches. Functionally, the cynomolgus monkey liver can be divided into eight independent segments. Thus, we report the first detailed description of the hepatic and portal surgical anatomy of the cynomolgus monkey. The cynomolgus monkey liver is more similar to the human liver than are livers of any small or large nonprimate mammals that have been described. Am. J. Primatol. 71:400–408, 2009. © 2009 Wiley‐Liss, Inc.
Birch Reduction of Benzene in a Low‐Temperature Plasma
Authors: Na Na , Xia Yu , Zhu Zhenli , Zhang Xinrong , Cooks R. Graham
Published: February 2009

Selektive und spezifische Dihydrierungen von Benzol und anderen Arenen wurden in einem Tieftemperatur‐Heliumplasma beobachtet. Im vorgeschlagenen Mechanismus werden die Benzolmoleküle an der Entladungsoberfläche adsorbiert. Dort fangen sie in einer Birch‐Reduktion zunächst adsorbierte niederenergetische Elektronen ein und werden anschließend protoniert (siehe Bild). Die Reduktionsreaktion wird von Oxidationsprozessen in der Gasphase begleitet.

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Nachweis von Drogenmissbrauch durch Nanopartikel‐verstärktes Fluoreszenz‐Imaging von latenten Fingerabdrücken
Authors: Wolfbeis Otto S.
Published: February 2009

Der Schweiß eines Fingerabdrucks kann oral eingenommene Drogen und ihre Metaboliten enthalten. Bei einer neuen Methode zum Drogennachweis werden primäre Antikörper gegen Drogenmetabolite mit magnetischen Nanopartikeln konjugiert. Diese werden dann zur Inkubation auf den Abdruck aufgebracht, nach Entfernung mit einem fluoreszenzmarkierten Antikörper behandelt und nochmals inkubiert. Die Charakterisierung erfolgt durch Fluoreszenz‐Imaging.

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Intermolecular Methoxycarbonylation of Terminal Alkynes Catalyzed by Palladium(II) Bis(oxazoline) Complexes
Authors: Kato Keisuke , Motodate Satoshi , Mochida Tomoyuki , Kobayashi Takuya , Akita Hiroyuki
Published: February 2009

Die direkte Umwandlung einer terminalen Alkinfunktion in einen β‐Methoxyacrylat‐Rest gelingt mithilfe eines Bisoxazolin(box)‐Liganden. Acetyl‐ und Ketal‐Schutzgruppen werden unter den Reaktionsbedingungen ebenso wenig angegriffen wie freie Hydroxygruppen und säureempfindliche glycosidische Bindungen. (±)‐Dihydrokawain wurde aus dem Homopropargylalkohol in einem Eintopfverfahren synthetisiert. tfa=Trifluoracetat.

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Stereogradient Polymers Formed by Controlled/Living Radical Polymerization of Bulky Methacrylate Monomers
Authors: Ishitake Kenji , Satoh Kotaro , Kamigaito Masami , Okamoto Yoshio
Published: February 2009

Life RAFT: A bulky methacrylate monomer, triphenylmethyl methacrylate (TrMA), was polymerized with reversible addition–fragmentation chain transfer (RAFT) agents. Stereogradient polymers in which the isospecificity increased spontaneously as the monomer concentration decreased were formed by a polymerization–depolymerization equilibrium that can convert a less stable growing polymer terminal into a more stable form (see picture).

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Birch Reduction of Benzene in a Low‐Temperature Plasma
Authors: Na Na , Xia Yu , Zhu Zhenli , Zhang Xinrong , Cooks R. Graham
Published: February 2009

Selective and specific dihydrogenation of benzene and other arenes has been observed in a low‐temperature helium plasma. A surface Birch reduction mechanism has been proposed in which benzene molecules adsorbed on the discharge surface capture low‐energy surface‐adsorbed electrons and subsequently undergo protonation (see picture). Gas‐phase oxidation processes accompany the reduction reaction.

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A Stable and Crystalline Triarylgermyl Radical: Structure and EPR Spectra
Authors: Drost Christian , Griebel Jan , Kirmse Reinhard , Lönnecke Peter , Reinhold Joachim
Published: February 2009

A radical thing: After being obtained unexpectedly in low yields, the synthesis of the first stable triarylgermyl radical .Ge[3,5‐tBu2‐2,6‐(EtO)2C6H]3 (1; C gray, O blue) was considerably optimized, and the product was investigated by X‐ray analysis and EPR spectroscopy. The results were compared with DFT‐MO studies for the model compound .Ge[2,6‐(MeO)2C6H3].

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What Does it Really Take to Stabilize Complexes of Late Transition Metals with Terminal Oxo Ligands?
Authors: Limberg Christian
Published: February 2009

Surprisingly stable: Noble‐metal complexes with terminal oxo ligands are frequently postulated as intermediates, but they are generally considered elusive, as their d electrons destabilize the MO units. Until recently, the isolation of such compounds was thought to require strong acceptor ligands, but now a remarkably stable PtO complex has been obtained employing a simple pincer ligand.

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Ligand‐Stabilized Chalcogen Dications
Authors: Chivers Tristram , Konu Jari
Published: February 2009

Chalcogen‐transfer reagents? The bonding in the dicationic rings C2N2E2+ (see picture) differs from that in N‐heterocyclic carbenes and their isovalent p‐block analogues in accommodating a lone pair of electrons with π symmetry, as well as σ symmetry, on the chalcogen center. The labile electrophilic chalcogenium dications (E2+) are potentially versatile chalcogen‐transfer reagents in reactions with a variety of inorganic and organic substrates.

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Morphology and rheological behavior of maltene–polymer blends. I. Effect of partial hydrogenation of poly(styrene‐block‐butadiene‐block‐styrene‐block)‐type copolymers
Authors: González‐Aguirre Paola , Medina‐Torres Luís , Schrauwen Cornelius , Fonteix Christian , Pla Fernand , Herrera‐Nájera Rafael
Published: February 2009

Because of the importance of the maltene–polymer interaction for the better performance of polymer‐modified asphalts, this article reports the effects of the molecular characteristics of two commercial poly(styrene‐block‐butadiene‐block‐styrene‐block) (SBS) polymers and their partially hydrogenated derivatives [poly{styrene‐block[(butadiene)1−x–(ethylene‐co‐butylene)x]‐block‐styrene‐block} (SBEBS)] on the morphology and rheological behavior of maltene–polymer blends (MPBs) with polymer concentrations of 3 and 10% (w/w). Each SBEBS and its parent SBS had the same molecular weight and polystyrene block size, but they differed from each other in the composition of the elastomeric block, which exhibited the semicrystalline characteristics of SBEBS. Maltenes were obtained from Ac‐20 asphalt (Pemex, Salamanca, Mexico), and the blends were prepared by a hot‐mixing procedure. Fluorescence microscopy images indicated that all the blends were heterogeneous, with polymer‐rich and maltene‐rich phases. The rheological behavior of the blends was determined from oscillatory shear flow data. An analysis of the storage modulus, loss modulus, complex modulus, and phase angle as a function of the oscillatory frequency at various temperatures allowed us to conclude that the maltenes behaved as pseudohomogeneous viscoelastic materials that could dissipate stress without presenting structural changes; moreover, all the MPBs were more viscoelastic than the neat maltenes, and this depended on both the characteristics and amount of the polymer. The MPBs prepared with SBEBS were more viscoelastic and possessed higher elasticity than those prepared with SBS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Towards a metabolic and isotopic steady state in CHO batch cultures for reliable isotope‐based metabolic profiling
Authors: Deshpande Rahul , Yang Tae Hoon , Heinzle Elmar
Published: February 2009

Attaining metabolic and isotopic balanced growth is one critical condition for physiological studies using isotope‐labeled tracers, but is very difficult to obtain in batch culture due to the extensive metabolite exchange with the surrounding medium and related physiological changes. In the present study, we investigated metabolic and isotopic behavior of CHO cells in differently designed media. We observed that the assumption of balanced cell growth cannot be justified in batch culture of CHO cells directly using conventional, commercially available media. By systematically redesigning media composition and characterizing metabolic steady state based on mass balances and measurement of labeling dynamics, we achieved balanced cell growth for the main cellular substrates in CHO cells. This was done in a step‐by‐step analysis of growth and primary metabolism of CHO cells with the use of [U‐13C]glucose feeding and adjusting concentrations of amino acids in the growth medium. The optimized media obtained at the end of the study provide balanced growth and isotopic steady state or at least asymptotic steady state. As a result, we established a platform to conduct isotope‐based physiological studies of mammalian systems more reliably and therefore well suited for later use in metabolic profiling of mammalian systems such as 13C‐labeled metabolic flux analysis.
Julius Adolph Stöckhardt. Zum 200. Geburtstag
Authors: Boeck Gisela
Published: February 2009

Julius Adolph Stöckhardt, der den damals üblichen Weg vom Apotheker zum Chemiker ging, hat auf vielen Gebieten seine Spuren hinterlassen. Der Wegweiser seines Handelns war die Anwendbarkeit der chemischen Kenntnisse in der Praxis. Stöckhardt war einer der wichtigsten Popularisatoren der Agrikulturchemie, auf sein Bemühen geht im Wesentlichen die Gründung der landwirtschaftlichen Versuchsstationen zurück. Er hat sich mit Rauchgasen und Folgen für den Forst, mit der Giftigkeit von Farben auseinandergesetzt, zahllose analytische Untersuchungen – auch von Gesteinen – vorgenommen, über Methoden eines guten naturwissenschaftlichen Unterrichts nachgedacht und die Anerkennung der Chemie als allgemeines Bildungsmittel angestrebt. Im Andenken an diesen Gelehrten tragen heute das 1885 an der Forstakademie Tharandt erbaute, nun zur TU Dresden Fakultät für Forst‐, Geo‐ und Hydrowissenschaften gehörende Labor, der Chemnitzer Förderklub für chemieinteressierte Schülerinnen und Schüler, ein Chemiewettbewerb und ein jährlich an der Technischen Universität Chemnitz durchgeführtes Kolloquium zu Fragen der Umweltchemie seinen Namen.
Dramatische pH‐Änderung der Ozeane
Authors: Groß Michael
Published: February 2009

Die Weltmeere haben bisher einen mildernden Einfluss auf den Klimawandel durch von Menschen freigesetztes Kohlendioxid ausgeübt. Schätzungsweise ein Drittel des seit Beginn der Industrialisierung erzeugten CO2‐Überschusses hat sich im Meer gelöst und trägt damit vorerst nicht zum Treibhauseffekt bei. Erst vor einigen Jahren haben Experten bemerkt, dass dieser scheinbar positive Effekt katastrophale Nebenwirkungen mit sich bringt.
Symbiose ersetzt den Darm
Authors: Feil Sylvia
Published: February 2009

Unweit der Mittelmeerküste trifft man im Sediment auf Ringelwürmer, deren Darm sich aufgrund einer erfolgreichen symbiontischen Lebensweise mit Bakterien zurück gebildet hat. Dieser Wurm heißt Olavius algarvensis. Er gehört zu einer Gruppe von Oligochaeten des Stammes Annelida, die weder Mund noch Darm noch Anus haben: Ihr gesamtes Verdauungssystem ist reduziert.
Hydroxidionen bilden Wasserstoffbrücken
Authors: Harrer Roswitha
Published: February 2009

Das Hydroxidion in wässriger Lösung ist eines der universellsten negativ geladenen Teilchen. Dennoch sind die Kenntnisse seiner Hydratisierungsstruktur und seines Transports in wässriger Lösung noch unvollständig. Jetzt wiesen Forscher zum ersten Mal nach, dass hydratisierte Hydroxidionen auf umgebene Wassermoleküle selbst Wasserstoffbrückenbindungen ausbilden – als Wasserstoffdonor.
Approaches to determination of left ventricular volume and ejection fraction by real‐time two‐dimensional echocardiography
Authors: Parisi A. F. , Moynihan P. F. , Feldman C. L. , Folland E. D.
Published: February 2009

Left ventricular volumes and ejection fraction were derived from real time two‐dimensional echocardio‐graphic images (2 DE) and single plane (RAO) left ventricular cineangiograms in a series of 50 patients. Prospective application of a series of 6 alternate algorithms showed that a modified Simpson's rule approach using mitral and papillary muscle cross sections and an apical four chamber view provided the best 2 DE — angiographic correlations: for end‐diastolic volume r = 0.82, SEE = 39 ml; for end‐systolic volume r = 0.90, SEE = 29 ml and for ejection fraction r = 0.80, SEE = 0.09. The large SEE for volume determination indicates that further refinements are necessary to predict left ventricular volumes adequately; however, ejection fraction can be derived with an accuracy which allows practical clinical decisions in patients with satisfactory 2 DE images.
Comparison of plasma concentrations of thromboxane B2 in prinzmetal's variant angina and classical angina pectoris
Authors: Lewy R. I. , Wiener L. , Smith J. B. , Walinsky P. , Silver M. J. , Saia J.
Published: February 2009

We have reported that thromboxane B2 is present in plasma of Prinzmetal's angina patients measured by radioimmunoassay but is below detection limits, <0.5 pmol/ml, in normals. To determine whether this metabolite of thromboxane A2 (a coronary vasoconstrictor) is present in the peripheral blood in classical angina pectoris, we studied 14 patients with fixed obstructive coronary artery disease (2.5 lesions per patient) in whom angina was induced by atrial pacing. Thromboxane B2 at rest was barely detectable (0.537±0.16 pmol/ml), but rose during pacing (0.747±0.18 pmol/ml) and was maximal (p<0.05) 5–10 min after pacing (1.237±0.36 pmol/ml). In eight variant angina patients, resting levels of thromboxane B2 were not statistically different during spontaneous angina and angina‐free intervals (2.837±0.56 and 1.577±0.34 pmol/ml), but the mean 5–10 min after angina was higher than during angina (6.41 7±1.46 pmol). The means of preanginal, anginal, and postanginal samples were all higher than the corresponding means of the classical angina group, and thromboxane B2 levels in variant angina patients in the absence of angina, during angina, and 5–10 min after angina were all significantly higher (p<0.025) compared to the classical angina group measured prior to pacing. Unlike the case with variant angina, thromboxane B2 is indetectable in classical angina pectoris patients at rest. Furthermore, spontaneous angina in variant angina or pacing‐induced angina in classical angina pectoris are both followed by increased thromboxane B2, although the latter responses are smaller. The role of these phenomena in the pathogenesis of coronary artery spasm and ischemia remains to be clarified.
Giant lambl's excrescences of papillary muscle and aortic valve: echocardiography, angiographic, and pathologic findings
Authors: Cha S. D. , Incarvito J. , Fernandez J. , Chang K. S. , Maranhao V. , Gooch A. S.
Published: February 2009

A 54‐year‐old female with rheumatic heart disease was found to have a mass in the left ventricle by echocardiography and angiography. Subsequently, giant Lambl's excrescences of papillary muscle and aortic valve were confirmed by operation and pathologic examination. Possible complication from cardiac catheterization could be avoided by the utilization of echocardiography prior to catheterization.
Prostaglandin inhibition and myocardial infarct size
Authors: Jugdutt B. I. , Becker L. C.
Published: February 2009

In parallel with experimental research into methods for salvage of ischemic myocardium after acute myocardial infarction (AMI) over the last decade, there has been a growing interest in prostaglandins (PG) and their inhibition by aspirin‐like drugs or nonsteroidal anti‐inflammatory drugs (NSAID). The finding of enhanced PG release during myocardial ischemia and its blockade by the NSAID indomethacin led to the hypothesis that PG might influence the infarction process. Because PG differ in vasoactive, cellular, and metabolic properties, and PG inhibitors also differ in their ability to inhibit synthesis of different PG and their metabolites, some PG inhibitors might be expected to reduce myocardial ischemic injury and infarct size. In addition, the NSAID may directly modify cellular events during infarction. Experiments with NSAID in the anesthetized and conscious animals have demonstrated a reduction of myocardial infarct size with ibuprofen, but an increase in infarct size with indomethacin. The opposite effects of these agents on infarct size might have been related to the different doses used, different degrees of inhibition of PG and their metabolites, and different effects on factors influencing myocardial oxygen supply and demand, metabolic and cellular events during infarction. It has recently been suggested that some of these agents might also influence the healing process after AMI and, therefore, late complications. Thus, further critical studies are needed before embarking on clinical trials of these agents during AMI in humans
A Computerized approach to evaluating rest and exercise‐induced ecg/vcg changes after cardiac rehabilitation
Authors: Watanabe K. , Bhargava V. , Froelicher V.
Published: February 2009

Summary: A computerized method of acquiring and analyzing rest and exercise test 12‐lead electrocardiographic and three‐dimensional lead vectorcardiographic data before and after cardiac rehabilitations is described. Fourteen coronary heart disease patients were exercise tested before and after a mean of five months of aerobic exercise training. The only significant ST‐segment improvements were found in three‐dimensional space. Spatial measurements should be considered in the assessment of electrocardiographic changes secondary to exercise training.
Echo‐ and electrocardiographic findings in relation to autopsy in myocardial infarction
Authors: Lindvall K. , Erhardt L. , Sjogren A.
Published: February 2009

Summary: Left ventricular (LV) wall motion studied by echocardiography (Echo) may give additional information of site and extension of myocardial damage in myocardial infarction (MI) compared to conventional ECG. We have therefore investigated patients with apparent poor short‐term prognosis in the acute phase of an MI. Adequate autopsy data were available in 17 patients who died within a stipulated 2‐month period. The left ventricle was divided into 16 segments and concomitant evaluation with ECG and Echo was possible in 164 (56%) of 272 (16 × 17) segments. The Echo parameter mean systolic wall velocity (V) was used with its percent deviation (PD‐V) from that obtained in a healthy group. A reduction in PD‐V by 30% was used for separating healthy from infarcted segments. This limit gives the method a sensitivity (S) of 92%, specificity (SP) 66%, and predictive accuracy (PA) of 79% with highest PA for anterior and posteroseptal segments (78–87%) in contrast to inferior and lateral segments (73%). Sensitivity for single ECG leads is lower (76%) with SP and PA of 76 and 75%, respectively. PA was highest for an‐teroseptal and lateral segments (83%) as compared to 60% for inferoposterior segments. In 11 patients the MI was predominantly anterior which was adequately reflected by both Echo and ECG. Extension beyond this site was better evidenced by Echo than ECG. ECG was nondiagnostic in true posterior extension in contrast to Echo which was correct in all. In 6 patients the MI was predominantly inferior. Echo correctly identified this in 82% of segments and ECG in 71%. Again extensions beyond this site were better evidenced by Echo. Extensions to the true posterior and anterolateral walls were indicated in 79–100% by Echo, while ECG indicated MI in two posterior segments only. We conclude that Echo mapping provides useful information of segmental LV wall function in MI. In comparison to ECG additional information is obtained of MI involvement of especially the basal segments as well as the apical‐posteroseptal segments and also of extension beyond the conventional anterior and inferior locations.
Assessment of Diagnostic Value of Dipyridamole Testing in Angina Pectoris
Authors: Deambroggi L. , Barbieri P. , Debiash A. M. , Repetto S. , Radice M.
Published: February 2009

Summary: In order to assess the diagnostic value of dipyridamole (D) testing, we studied the responses of 34 patients with chest pain and 10 normal subjects. Blood pressure and 12‐lead ECG were recorded during and after intravenous infusion of 0.6 mg/kg dipyridamole for 10 minutes. Coronary arteriography and maximal or symptom‐limited exercise tests were performed in the 34 patients with chest pain. During infusion 13 patients presented ischemic ST changes and 5 with anginal pain only. The latter group had normal coronary arteries. Among the 13 patients with ischemic ST changes, 7 had at least two critical coronary stenoses and the remaining 6 had no coronary lesions. Dipyridamole tests showed poor sensitivity (44%) and specificity (39%) with respect to coronary arteriography. The relatively high number of positive responses in subjects with normal coronary arteries indicates that the coronary steal phenomenon is not the sole cause of “ischemic” response to the drug. Indirect indexes of myocardial oxygen consumption were higher in patients with a positive response to drug infusion than in those with a negative response; however the value of rate‐pressure product at infusion end never reached that observed at ischemic threshold during exercise testing in the same patient. This suggests that neither can oxygen consumption increase be considered as entirely responsible for ischemic response to dipyridamole. In conclusion dipyridamole test cannot be proposed for predicting critical coronary stenoses.
Propranolol effects on autonomic function in hypertensive men
Authors: O'Connor D. T. , Preston R. A.
Published: February 2009

Summary: Beta blocker antihypertensive effects are incompletely understood, and may involve alterations in the autonomic nervous system. We studied autonomic function in 12 essential hypertensive men during treatment with placebo and chronic oral propranolol. Propranolol reduced blood pressure and heart rate (both p<0.01) with an associated increase in baroreflex sensitivity during phenylephrine testing (p<0.02), though amyl nitrite‐tested baroreflex sensitivity was unchanged; blood pressure decrement did not correlate with baroreflex enhancement. Response to the cold pressor test and the blood pressure decrement to phentolamine alpha blockade were unaltered by propranolol, suggesting unchanged efferent sympathetic function; nor were several biochemical indices of sympathetic nervous activity influenced by propranolol. Propranolol does perturb autonomic function in man, but the perturbations do not correlate with blood pressure decrement; nor are physiologic or biochemical indices of efferent sympathetic activity reduced by propranolol.
Primary versus secondary mitral valve prolapse: Clinical features and implications
Authors: Levine H. J. , Isner J. M. , Salem D. N.
Published: February 2009

Summary: This study considers the implications that two types of mitral valve prolapse exist. One is primary, and consists of a basic abnormality of the mitral apparatus. While the etiology of this lesion may not always be the same, the major gross abnormalities are usually constant. Secondary mitral valve prolapse generally exists merely as a consequence of reduced or abnormal ventricular dimensions, and usually appears to be a benign phenomenon.
Ventricular septal defect and mitral regurgitation complicating acute myocardial infarction
Authors: Corbally F. , Lowney J. D. , Schiff S. , Gottlieb R. , Papa L. A.
Published: February 2009

We report a case of rare incidence of both ventricular septal rupture and mitral regurgitation that followed an acute myocardial infarction in a 77‐year‐old woman. The literature contains few reports of such cases. The following reports both events and the progression of the clinical events.
Prolonged persistence of a large pericardial effusion and hemodynamic evidence of cardiac tamponade during treatment of myxedema
Authors: Das S. , Lieberman A. N. , Schussler G. C.
Published: February 2009

We describe clinical, echocardiographic, and catheterization findings that were present initially and during therapy in a myxedematous patient with a large pericardial effusion and tamponade. Treatment with thyroxine resulted in a marked improvement of most of the clinical features of hypothyroidism and some improvement in cardiac function. However, the pericardial effusion as well as clinical and laboratory evidence of tamponade persisted for 2 months after full replacement doses of T4 had been achieved. The tamponade was finally relieved by fenestration of the parietal pericardium. These findings are consistent with evidence of an abnormality of pericardial drainage that persists for months after other thyroid hormone dependent functions are normalized by thyroxine replacement. Therefore prompt surgical drainage rather than dependence on medical therapy alone is indicated in myxedematous patients who have cardiac tamponade.
The pulmonary circulation and its systemic arterial supply in pulmonary atresia
Authors: Schneeweiss A. , Shem‐Tov A. , Dicker D. , Blieden L. C. , Deutsch V. , Neufeld H. N.
Published: February 2009

The pulmonary circulation and its systemic arterial supply in cases of pulmonary atresia were studied angiocardiographically. In 69% of the cases the pulmonary arteries were hypoplastic and supplied by a patent ductus arteriosus or a few large systemic arteries. A classification into four groups is suggested, and a developmental paradox represented by this classification is discussed.
Suppression of ventricular arrhythmia by acebutolol
Authors: Santoso T. , Nursyirwan E. F. , Trisnohadi H. B. , Manurung D. , Rahman A. M. , Abdurahman N.
Published: February 2009

To study the efficacy of acebutolol in suppressing ventricular arrhythmia, 20 consecutive patients with more than 10 premature ventricular contractions (PVCs) per hour (averaged over 24 hours) were studied. Arrhythmias were not precipitated either by remediable clinical conditions or acute myocardial infarction. Digitalis and antiarrhythmic drugs were discontinued at least 5 days prior to entry into the trial. Besides routine clinical, laboratory, and ECG examinations, all patients also underwent serial 24‐h Holter monitoring every 10 days and echocardiographic examinations before and 20 days after treatment. The total duration of the trial was 30 days. The dosage of acebutolol was 400 mg/d during the first 10 days and was increased to 600 mg/d in the next 10 days as necessary, provided also that no significant side effects occurred. The drug was withdrawn for the last 10 days in order to establish drug withdrawal effects. Drug efficacy was assessed quantitatively by calculating the number of PVCs per day, and qualitatively by using the Lown grading system. There were 3 dropouts. Of the 17 patients who completed the trial, 10 (59%) showed a reduction of PVCs of at least 65%, and in 9 (53%) this occurred on a dosage of 400 mg/d. Elimination of grade 4A or 4B arrhythmia was observed in 6 (67%) of 9 patients. Although most patients were normotensive before entry into trial, none developed a drop in systolic blood pressure to 100 mmHg or less. The heart rate decreased slightly but significant bradycardia was not noted. Acebutolol did not adversely affect left ventricular function as assessed echocardiographically. We conclude that acebutolol is safe and effective for the treatment of PVCs And in most patients may be administered in a dosage of 200 mg twice daily.
The cardiovascular response at rest and during exercise in hypothyroid subjects to thyroxine substitution
Authors: Hylander B. , Ekelund L.‐G. , Rosenqvist U.
Published: February 2009

Rapid and intense thyroxine substitution can lead to heart failure and myocardial infarction in hypothyroid patients. We have analyzed the normalization of the circulatory system in hypothyroid subjects on a gradual thyroxine substitution. Fourteen hypothyroid patients were studied repeatedly with an orthostatic test and a standardized symptom‐limited exercise test during substitution. ST and T abnormalities were observed in 51 and 33%, respectively, before substitution. Many of these changes were normalized upon substitution at a dose level of 0.15 mg/d thyroxine. The pulse reaction to standing was enhanced early during substitution. The capacity to perform work, on the other hand, responded more slowly to thyroxine substitution, and was significantly increased only after six months of full substitution. This difference in the time course of recovery may be of clinical importance when substituting patients with hypothyroidism and ischemic heart disease.
Hypothyroidism, Raynaud's phenomenon, and acute myocardial infarction in a young woman
Authors: Sipilä R. , Viitasalo K. , Heikkilä J.
Published: February 2009

We describe an acute inferior myocardial infarction in a 29‐year‐old woman with normal coronary arteries. She has suffered from Raynaud's phenomenon in the fingers for several years. Manifest thyroid deficiency was discovered during hospitalization. A functional‐type link between hypothyroidism and myocardial infarction via vasospasm manifested as Raynaud's phenomenon is proposed as one possible etiology for the syndrome of myocardial infarction in young women.
Large V waves in the pulmonary capillary wedge pressure tracing without mitral regurgitation: He influence of the pressure/volume relationship on the V wave size
Authors: Pichard A. D. , Diaz R. , Marchant E. , Casanegra P.
Published: February 2009

We have previously demonstrated that a large V wave in the pulmonary capillary wedge tracing may occur in the absence of mitral regurgitation. This study evaluates the role of left atrial and pulmonary vein compliance on such a finding. We studied 11 patients with coronary disease, without clinical or angiographic mitral regurgitation. Heart rate, pulmonary capillary wedge mean, A and V waves, V‐wave slope, left ventricular and aortic pressures, cardiac output, and left atrial echo and apical phonocardiogram were recorded simultaneously. Preload was modified acutely by volume overload and by the administration of i.v. nitroglycerine. Volume administration induced a marked increase in V‐wave pressure (13.0±9.6 vs. 27.0±9.6 mmHg, p<0.05), without producing mitral regurgitation, and without appreciable change in left atrial dimension by echo (33.0±4.9 vs. 35.5±5.2 mm, NS), or stroke volume (101.7±26.2 vs. 97.8±34.3 ml, NS). An increase was also seen in the A wave (13.6±8.9 vs. 23.3±8.5 mmHg, p<0.05), pulmonary capillary wedge mean pressure (9.8±7.2 vs. 20.6±7.8 mmHg, p<0.05), and left ventricular diastolic pressure (7.4±5.5 vs. 14.6±6.3 mmHg, p<0.05). All values returned to baseline after nitroglycerine. The compliance of the left atrium/pulmonary veins decreased with increasing pulmonary capillary wedge pressures. With large filling volumes, a small stroke volume brings on a large pressure change, thus explaining the finding of large V waves in patients with elevated pulmonary capillary wedge pressure and without mitral regurgitation.
Assessment of valvular heart disease by doppler echocardiography
Authors: Pearlman A. S. , Scoblionko D. P. , Saal A. K.
Published: February 2009

Doppler echocardiography provides direct hemodynamic data that are often complementary to those demonstrated by M‐mode and two‐dimensional echocardiographic imaging. This relatively new noninvasive technique has a number of important uses in patients with valvular heart disease. In both adults and children, Doppler measures of peak flow velocity through a stenotic valve allow accurate prediction of the pressure gradient across the valve, and the technique has particular promise for screening patients with suspected aortic or pulmonic stenosis. In patients with mitral stenosis but parasternal short‐axis images of limited quality, Doppler velocity measures can provide novel data about the pressure gradient and mitral orifice area. Doppler techniques can also provide direct evidence for or against the presence of valvular regurgitation, and several approaches allow clinically useful estimation of the extent of aortic, mitral, or tricuspid regurgitation. In patients with known disease of one cardiac valve, Doppler is accurate for evaluating the integrity of a second valve. Finally, Doppler techniques have great promise for defining the nature, and perhaps the severity, of suspected prosthetic valve malfunction. Hence, we believe that Doppler echocardiography should become a routine part of the noninvasive evaluation of patients with known or suspected valvular heart disease.
Salvage of an ischemic limb by laser angioplasty: Description of a New Technique
Authors: Ginsburg R. , Kim D.‐S. , Guthaner D. , Toth J. , Mitchell R. S.
Published: February 2009

A 62‐year‐old male with severe claudication and rest pain of the left leg resulting from a totally occluded superficial femoral artery and a 95 % stenosis of the deep femoral artery was treated with laser angioplasty after attempts at surgical revascularization were unsuccessful. A 200 μU silica fiber was inserted through a catheter and advanced into the lesion using 2 watts of delivered energy from an argon laser source. The fiber was then withdrawn from the lesion using 7 watts of energy to enlarge the lumen. No complications occurred, and posterior tibial blood flow was reestablished, as shown by Doppler flow measurements and resolution of clinical symptoms. We report a new technique of transcatheter fiberoptic‐directed argon laser radiation (laser angioplasty) for the treatment of occlusive vascular disease.
Pulse generator failure due to blunt trauma
Authors: Gould L. , Betzu R. , Taddeo M. , Judge J. D. , Lee J.
Published: February 2009

This case describes a 69‐year‐old male who had a permanent pacemaker implanted for sick sinus syndrome. He was struck by a car with a resultant failure of the pulse generator. Trauma‐related failure of a pulse generator is a rare event. Its recognition is imperative in the overall management of the trauma patient.
The effects of grapefruit pectin on patients at risk for coronary heart disease without altering diet or lifestyle
Authors: Cerda J. J. , Robbins F. L. , Burgin C. W. , Baumgartner T. G. , Rice R. W.
Published: February 2009

Dietary intake of cholesterol has been linked to coronary heart disease. The effect of grapefruit pectin (Citrus paradisi) on plasma cholesterol, triglycerides, very low‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, and the low‐density lipoprotein:high‐density lipoprotein cholesterol ratio was studied. The study design was a 16‐week double‐blind, crossover (placebo or pectin) using 27 human volunteers screened to be at medium to high risk for coronary heart disease due to hypercholesterolemia. The study did not interfere with the subjects' current diet or lifestyle. Grapefruit pectin supplementation decreased plasma cholesterol 7.6%, low‐density lipoprotein cholesterol 10.8%, and the low‐density lipoprotein:high‐density lipoprotein cholesterol ratio 9.8%. The other plasma lipid fractions studied showed no significant differences. We conclude that a grapefruit pectin‐supplemented diet, without change in lifestyle, can significantly reduce plasma cholesterol.
Grapefruit pectin inhibits hypercholesterolemia and atherosclerosis in miniature swine
Authors: Baekey P. A. , Cerda J. J. , Burgin C. W. , Robbins F. L. , Rice R. W. , Baumgartner T. G.
Published: February 2009

We studied the effect of dietary grapefruit pectin on plasma cholesterol and the development of atherosclerosis in 18 miniature swine. Pigs were randomized to one of three diets: no added fat (I), added fat/cellulose (II), and added fat/pectin (III). Plasma cholesterol was measured monthly. Arteries were examined for atherosclerosis at the termination of the experiment. Pectin supplementation of an added fat diet resulted in a significantly lower average plasma cholesterol than did cellulose supplementation (168 mg/dl vs. 249 mg/dl, p<0.05). The pectin‐fed pigs also developed less atherosclerosis of their aortas (1.1% vs. 7.0%, p<0.05) and coronary arteries (2.9% vs. 26.2% cross‐sectional narrowing, p<0.05). Plasma cholesterol levels correlated with the severity of aortic (r=0.836) and coronary artery (r=0.735) atherosclerosis. We conclude that dietary grapefruit pectin supplementation inhibits hypercholesterolemia and appears to be proportionately protective against atherosclerosis.
Handgrip strength afterthe blalock‐taussig shunt: 14 to 34 year follow‐up
Authors: Zahka K. G. , Manolio T. A. , Rykiel M. J. F. , Abel D. L. , Neill C. A. , Kidd L.
Published: February 2009

To determine the long‐term functional impact of the Blalock‐Taussig (BT) shunt, we studied handgrip strength in 56 patients (10–28 years) following total repair of tetralogy of Fallot. Of the 56, 16 (29%) had a previous right BT shunt, 5 of 56 (9%) had a previous left BT shunt, and the remaining 35 patients either had a Potts shunt or primary total repair. The mean age at the time of right BT was 2.8 ±1.6 (SD) years, left BT 1.7±1.2 years, and total repair for all patients was 7.1 ±2.2 years. Mean age at the time of study was 26±9 years. Right‐and left‐handgrip strength were measured with a Jamar dynamometer, averaging the results of grip position 2,3, and 4 to accomodate variation in hand size. Since absolute values of hand strength were strongly associated with sex (p=0.006) and body surface area (p=0.016), we calculated the ratio of right‐hand to left‐handgrip strength (RL ratio). The RL ratios were: 0.98±0.13 (right BT), 1.21 ±0.11 (left BT), and 1.13±0.16 (no BT): (p=0.004 right BT vs. no BT, p=0.07 left BT vs. no BT, Wilcoxon rank sum test). Thus, although frequently clinically inapparent, handgrip strength tested many years post‐BT shunt is reduced on the side of the shunt.
The electrophysiological effects of intravenous magnesium on human sinus node, atrioventricular node, atrium, and ventricle
Authors: Rasmussen H. S. , Thomsen P. E. B.
Published: February 2009

The effects of intravenously (IV) administered magnesium chloride (MgCl) on electrophysiologic and electrocardiographic variables were studied in 13 patients undergoing a routine electrophysiologic assessment for clinical indications. An infusion of 12 mmol of MgCl was given during a 10‐min period and relevant electrophysiologic variables were determined before and after the infusion. Serum Mg levels increased from 0.78±0.03 (mean±SEM) before to 1.52±0.08 ms after the infusion (p<0.0001). Magnesium treatment caused a significant prolongation in PR interval (from 151±8 to 174±8 ms, p<0.001) as well as in QRS duration (from 90±4 to 101±6 ms, p <0.05). Likewise, intra‐atrial (PA) as well as atrioventricular (AV) nodal (AH) conduction times were significantly prolonged (from 33±3 to 46±3 ms, p<0.01, and from 85±6 to 94±6 ms, p<0.05, respectively). Mean effective and functional atrial refractory periods increased (from 228±8 to 256±10 ms, p<0.01 and from 292±9 to 320±11 ms, p<0.001, respectively), as did mean AV node functional refractory period (from 399±29 to 422±27 ms, p<0.02). No significant change occurred with regard to sinus node function (as estimated from heart rate, sinus node recovery time, and calculated sinoatrial conduction time) or ventricular refractoriness. It is concluded that IV Mg has several electrophysiologic effects that may be beneficial in the treatment/prevention of supraventricular tachyarrhythmias.