bluuebunny/crossref_metadata_2025 huggingface dataset:
Pattern‐Based Recognition of Heparin Contaminants by an Array of Self‐Assembling Fluorescent Receptors
Authors: Jagt Richard B. C. , Gómez‐Biagi Rodolfo F. , Nitz Mark
Published: February 2009

Tracking down potential killers: Strong host–guest interactions enable the facile combination of polycationic cyclodextrin binding motifs (blue) with fluorescent reporters (orange) tethered to a hydrophobic guest molecule (dark green). An array of supramolecular fluorescent receptors prepared by this modular approach was used for the pattern‐based recognition of negatively charged contaminants in the anticoagulant drug heparin.

magnified image
Using rubrics to assess information literacy: An examination of methodology and interrater reliability
Authors: Oakleaf Megan
Published: February 2009

Academic librarians seeking to assess information literacy skills often focus on testing as a primary means of evaluation. Educators have long recognized the limitations of tests, and these limitations cause many educators to prefer rubric assessment to test‐based approaches to evaluation. In contrast, many academic librarians are unfamiliar with the benefits of rubrics. Those librarians who have explored the use of information literacy rubrics have not taken a rigorous approach to methodology and interrater reliability. This article seeks to remedy these omissions by describing the benefits of a rubric‐based approach to information literacy assessment, identifying a methodology for using rubrics to assess information literacy skills, and analyzing the interrater reliability of information literacy rubrics in the hands of university librarians, faculty, and students. Study results demonstrate that Cohen's κ can be effectively employed to check interrater reliability. The study also indicates that rubric training sessions improve interrater reliability among librarians, faculty, and students.
The f index: Quantifying the impact of coterminal citations on scientists' ranking
Authors: Katsaros Dimitrios , Akritidis Leonidas , Bozanis Panayiotis
Published: February 2009

Designing fair and unbiased metrics to measure the “level of excellence” of a scientist is a very significant task because they recently also have been taken into account when deciding faculty promotions, when allocating funds, and so on. Despite criticism that such scientometric evaluators are confronted with, they do have their merits, and efforts should be spent to arm them with robustness and resistance to manipulation. This article aims at initiating the study of the coterminal citations—their existence and implications—and presents them as a generalization of self‐citations and of co‐citation; it also shows how they can be used to capture any manipulation attempts against scientometric indicators, and finally presents a new index, the f index, that takes into account the coterminal citations. The utility of the new index is validated using the academic production of a number of esteemed computer scientists. The results confirm that the new index can discriminate those individuals whose work penetrates many scientific communities.
Specific absorption rate and electric field measurements in the near field of six mobile phone base station antennas
Authors: Toivonen Tommi , Toivo Tim , Puranen Lauri , Jokela Kari
Published: February 2009

In this article, the exposure to radio frequency electromagnetic fields was studied in close proximity (distances of 10, 100, 300, and 600 mm) to six base station antennas. The specific absorption rate (SAR) in 800 mm × 500 mm × 200 mm box phantom as well as unperturbed electric field (E) in air was measured. The results were used to determine whether the measurement of local maximum of unperturbed electric field can be used as a compliance check for local exposure. Also, the conservativeness of this assessment method compared to the ICNIRP basic restriction was studied. Moreover, the assessment of whole‐body exposure was discussed and the distance ranges presented in which the ICNIRP limit for local exposure could be exceeded before the limit for whole‐body SAR. These results show that the electric field measurement alone can be used for easy compliance check for the local exposure at all distances and for all antenna types studied. However, in some cases when the local peak value of E was compared directly to the ICNIRP reference level for unperturbed E, the exposure was overestimated only very slightly (by factor 1.1) compared to the basic restriction for localized SAR in a human, and hence these results can not be generalized to all antenna types. Moreover, it was shown that the limit for localized exposure could be exceeded before the limit for the whole‐body average SAR, if the distance to the antenna was less than 240 mm. Bioelectromagnetics 30:307–312, 2009. © 2009 Wiley‐Liss, Inc.
Production of glucolipids and specialty fatty acids from sophorolipids by Penicillium decumbens naringinase: Optimization and kinetics
Authors: Saerens Karen , Van Bogaert Inge , Soetaert Wim , Vandamme Erick
Published: February 2009

In view of global environmental concerns and the awakening to the exhaustibility of our natural resources, an increasing importance of biologically derived surfactants can be expected in the near future. Enzymatic modification of these biosurfactants allows to improve their characteristics and so extend their application field. In view of this, glucolipids are interesting substrates e.g., for the synthesis of new glycolipids with increased biological activity. Here, we describe the optimization of glucolipid production from Candida bombicola sophorolipids by Penicillium decumbens naringinase and show that the enzyme might be useful for production of specialty fatty acids as well. Optimum conditions for production of glucolipids were found to be pH 7.0 and 50°C with a yield of 80% (w/w) glucolipids after 3 h of incubation. The Km for sophorolipids was 1.67 mM, while Vmax was 0.035 mM sophorolipids/min. At pH 3.0, glucolipids were immediately further hydrolyzed and completely converted to fatty acids after 24 h of incubation, offering a biological route to the synthesis of unique specialty fatty acids. The Km for glucolipids was 11 mM while Vmax was 0.21 mM glucolipids/min. Glucose inhibited the enzyme in a competitive way with KI around 10‐15 mM glucose. Surfactant properties of the produced glucolipids were comparable to those of the acidic sophorolipids.
The effect of bacterial glutathione S‐transferase on morpholine degradation
Authors: Emtiazi Giti , Saleh Tayebe , Hassanshahian Mehdi
Published: February 2009

Glutathione S‐transferases (GSTs) constitute a large family of enzymes that catalyze the addition of glutathione to endogenous, or xenobiotic, often toxic electrophilic compounds. The effect of this enzyme in facilitating polychlorinated biphenyls degradation has been studied previously. Here the effects of induced cell‐free extracts of Acinetobacter calcoaceticus and Pseudomonas aeruginosa (grown on hexadecane), and E. coli BL21 (induced with pGEX‐2T plasmid on isothiopropylgalactoside) were recruited to facilitate morpholine degradation by Mycobacterium and were compared with non‐induced strains. The results showed that all induced strains had significantly more GST activity compared to non‐induced ones, and the strain with most GST activity, A. calcoaceticus BS, removed morpholine faster. Eukaryotic GST gene expressed in E. coli BL21 also could facilitate morpholine degradation by Mycobacterium, The same experiments performed with cell‐free extracts of non‐induced cells did not show any significant effects on morpholine removal. These results showed that there is a correlation between GST activity and acceleration of morpholine degradation.
Polymehr Perspektiven!
Authors: Roll J. , Sadowski G.
Published: February 2009

Für Absolventen von Bachelorstudiengängen wie Chemie, Chemieingenieurwesen oder Materialwissenschaften gibt es mit dem Masterstudiengang Polymerwissenschaften nun ein Angebot, das ihre Chancen am Arbeitsmarkt deutlich verbessert. Die Kombination der Polymerchemie mit Themenstellungen der Ingenieur‐ bzw. Materialwissenschaften eröffnet zusätzliche Perspektiven auf dem Arbeitsmarkt.
Ein perfekter Kleber
Authors: Harrer Roswitha
Published: February 2009

Was Geckos können, dazu sind wir noch lange nicht in der Lage: Einen Klebstoff zu benutzen, der wie die Gecko‐Fußzehen stark am Untergrund haftet, sich leicht ablöst, haftet, sich ablöst. Nun wurde das bislang genaueste Abbild der Klebe‐Struktur an den Zehen der Geckofüße hergestellt. Haftung und Lösung gelangen durch Ab‐ und Anschalten eines Magnetfeldes.
Fetal cardiovascular system as influenced by maternal smoking
Authors: Asmussen I.
Published: February 2009

Primary prevention of atherosclerosis should be initiated early in life, preferably in childhood. Nevertheless, it tends to be forgotten that a child has existed for nine months before birth, and that the newborn child might already have been exposed to agents capable of causing vessel damage.

Studies of the umbilical artery, umbilical vein, and vessels of the placental villi (2, 3, 4, 5, 6) revealed that, in this portion of the fetal cardiovascular system, severe damage to the vessel wall is associated with maternal tobacco smoking during pregnancy. These alterations within the fetal cardiovascular system were never found in the children of non‐smoking mothers. If similar changes occur in the other vessels of the newborn child, which it seems reasonable to expect, they might give rise to sequelae later in life. It should therefore strongly be advocated that pregnant women abandon tobacco smoking.
Patient profile and follow‐up in medically and surgically treated young adults with myocardial infarction
Authors: Mcmartin D. E. , Masden R. R. , Sohi G. S. , Flowers N. C.
Published: February 2009

Twenty‐four young patients with myocardial infarction (average age 32.1 years) undergoing coronary arteriography after infarction were followed for an average of 33 months after catheterization. Prior inferior infarction was a predictor of two and three vessel coronary occlusive disease. Prior anterior infarction patients had a 64% incidence of single vessel coronary occlusive disease. Improvement in anginal symptoms over the follow‐up period from the time of catheterization for the entire group was 69%. Employment at follow‐up was excellent in both medically and surgically treated patients (80%). Cardiac mortality from the time of catheterization was extremely low (4%).
Lidoflazine in the management of angina pectoris
Authors: Bloem Th. J. J. M. , Vermeulen A. , Reneman R. S.
Published: February 2009

The effect of lidoflazine administration (120 mg t.i.d. for 9 weeks) on work tolerance (bicycle ergometer), frequency of anginal attacks, and nitroglycerin consumption was investigated in 28 male patients with stable angina pectoris in a combined single‐blind/double‐blind study. Lidoflazine increased work tolerance and reduced the frequency of anginal attacks and nitroglycerin consumption. The higher work tolerance level was reached at maximal heart rate and heart rate‐systolic blood pressure product values similar to those before treatment. The values of these variables after 3 min of exercise at 60 W, however, were significantly lower after treatment with lidoflazine. These findings indicate that the heart is performing more economically during lidoflazine treatment. The improved work tolerance can probably be ascribed to lidoflazine and not to a training effect because of the significant reduction of this variable in the patients allocated to placebo as compared to those remaining on lidoflazine treatment. The side effects were generally slight. In one patient the prolongation of the QT interval due to lidoflazine resulted in rhythm disturbances.
Myocardial metabolism of cyclic 3,5‐adenosine monophosphate as influenced by dipyridamole and theophylline in patients with coronary heart disease
Authors: Hombach V. , Behrenbeck D. W. , Tauchert M. , Gil‐Sanchez D. , Jansen W. , Hötzel J. , Niehues B. , Hilger H. H.
Published: February 2009

In a total of 16 individuals, 4 females and 12 male patients ranging from 36 to 54 years, with proven coronary heart disease, hemodynamic parameters and coronary blood flow (argon method) were measured at rest and after administration of dipyridamole, 0.5 mg/kg body weight, and theophylline, 0.24 g i.v. Simultaneously, blood samples were taken from the arterial and coronary venous blood for determinations of oxygen content and concentrations of cyclic 3,5‐adenosine monophosphate (cAMP) and lactate. Thus, myocardial oxygen consumption and uptake or release of cAMP and lactate could be calculated according to the Fick principle.

After administration of dipyridamole, heart rate and cardiac index slightly increased together with a decrease in arterial pressure. Myocardial blood flow significantly increased, whereas myocardial oxygen consumption remained unchanged during the dipyridamole period. In nine patients myocardial release of cAMP and lactate could be observed during the dipyridamole action, whereas in the remaining seven patients there were only insignificant changes of release or uptake of cAMP and lactate in the dipyridamole and theophylline periods. Six of nine patients in the first group revealed specific anginal complaints corresponding to the release of cAMP and lactate, whereas only two patients in the non‐cAMP‐releasing individuals had characteristic angina pectoris.

These data suggest that dipyridamole may induce myocardial ischemia with anginal complaints and that, under certain circumstances, myocardial release of cAMP as well as lactate might serve as biochemical correlates of these ischemic conditions.
Reliability and reproducibility of interpretation of 99m technetium pyrophosphate myocardial scintigrams
Authors: Mason J. W. , Myers R. W. , Goris M. L. , Doherty P. , Alderman E. L. , Kriss J. P.
Published: February 2009

The interpretations of 156 99mtechnetium pyrophosphate myocardial scintigrams by four observers were analyzed in order to determine the reliability and reproducibility of the subjective process of reading scintigrams. The scintigrams were scored on an integral scale from 0 to 4, depending upon the degree of myocardial radionuclide accumulation, and the site and nature of uptake were specified. Exact agreement upon score was generally poor but approximate concurrence of interpretation was good (90.4 and 92.5% inter‐ and intra‐observer agreement, respectively). There was somewhat less agreement on scintigrams with the higher scores of 3 and 4 (83.3 and 78.0%, respectively). A high level of concurrence upon the differentiation between diffuse and localized uptake, and upon the site of uptake, was found. We conclude that only approximate rather than exact agreement of individual readers' interpretations can be expected in this subjective technique, that scintigrams with higher degrees of radionuclide accumulation produce slightly greater observer disagreement, and that variability of interpretation could account for some of the diagnostic inaccuracy of 99mtechnetium pyrophosphate myocardial scintigraphy.
The prognosis of anterior myocardial infarction revisited: A community‐wide study
Authors: Kennedy H. L. , Goldberg R. J. , Szklo M. , Tonascia J. A.
Published: February 2009

A study was carried out in metropolitan Baltimore in which the short‐ and long‐term prognosis of 655 patients with anterior myocardial infarction (MI) was compared with that of 520 patients with inferior/posterior MI. The study was performed on a community‐wide basis in two time periods before the clinical introduction and widespread use of beta‐blockade therapy. After simultaneous adjustment for several socio‐demographic and clinical variables, the in‐hospital case fatality rate was greater for patients with anterior (27.5%) than for those with inferior/posterior MI (22.9%) (p<0.05). Similarly, for those discharged alive from the hospital and followed up for as long as 10 years, patients with infarction of the anterior wall had a significantly poorer long‐term survival than that of patients with infarction of the inferior/posterior wall (p<0.05). These results suggest that closer surveillance should be directed at patients with anterior myocardial infarction, both during the acute phase and after hospital discharge.
Evaluation of aortic and mitral valve regurgitation by radionuclide ventriculography: Comparison with the method of sandler and dodge
Authors: Kress P. , Geffers H. , Stauch M. , Nechwatal W. , Sigel H. , Bitter F. , Adam W. E.
Published: February 2009

The present investigation was undertaken to introduce a quantitative scintigraphic method for evaluation of regurgitation and to compare it with the generally accepted quantitative method of Sandler and Dodge (Sandler et al., 1963).

Radionuclide ventriculography was carried out after injection of 20 mCi 99mtechnetium‐labeled red blood cells. Time‐activity curves were obtained from the left and right ventricular regions. The ratio (A) of end‐diastolic‐end‐systolic count‐rate differences for the left and right ventricles was calculated. The ratio (A) was compared with a hemodynamic ratio (Ah) determined after the method of Sandler and Dodge (1963) with the stroke volume of the left ventricle measured angiographically, and the stroke volume of the right ventricle measured by thermodilution.

In 33 patients with aortic and mitral valve regurgitation we found a correlation of r= 0.75 between (A) and (Ah). Due to a broad range of normal values of (A) the sensitivity of the scintigraphic method is low. The specificity seems to be high, however, since in 64 patients with all types of heart diseases there were no false positive results.

Comparing the described scintigraphic method with other modern or generally accepted methods, the principal advantages are noninvasiveness, good practicability, and the fact that important additional information about the functional state of the heart is gained. This is important in follow‐up studies in patients with chronic valvular incompetence.

It seems that this method will become a valuable supplement to heart catheterization in the diagnosis of valvular heart disease and may partially replace invasive methods for measuring the regurgitation fraction.
Evaluation of Platelet Kinetics following Porcine and Mechanical Valve Replacement
Authors: Lee G. , Joye J. A. , Rose A. , Denardo S. , Kozina J. A. , Mason D. T.
Published: February 2009

Because thromboembolic pathogenesis in mechanical prosthetic valves (MP) might involve selective MP platelet consumption with consequent reduced platelet survival, it has been suggested that lowered platelet half‐life (T1/2) detection provides identification of postoperative thrombotic risk. Porcine heterografts (PH) possess less thromboembolic hazards than MP; thus, comparative evaluation of PH versus MP platelet T1/2 is germane to the test's thrombotic predictive value, yet platelet kinetics in PH require elucidation. Accordingly, 51chromium platelet T1/2 was determined in 16 patients with substituted valves (10 PH and 6 MP). Average platelet T1/2 in PH (2.9±0.6 d) was similar (p>0.05) to MP (3.2±0.6 d), and both were considerably lower (p<0.05) than platelet T1/2 in normal subjects (NL, 5.1±0.5 d). Furthermore, platelet T1/2 was below the lowest NL platelet T1/2 (4.0 d) in seven PH and three MP patients. Thus, frequency and extent of decreased platelet survival in PH are common and equal to MP. These results indicate that platelet half‐life does not afford thromboembolic predictability in patients with mechanical valves and, instead, favors prosthetic‐induced physical trauma causing abnormal platelet survival.
Changes in cardiovascular function induced by verapamil in healthy subjects and in patients with ischemic heart disease
Authors: Vincenzi M. , Morlino T. , Allegri P. , Barbieri E. , Cappelletti F. , Delio U. , Ometto R. , Maiolino P.
Published: February 2009

Alterations in cardiovascular function induced by the acute intravenous administration of verapamil (5 or 10 mg) in 52 patients (29 with ischemic heart disease and 23 without heart disease) were evaluated with use of invasive techniques (right and left heart catheterization, left ventricular cineangiography, and coronary arteriography). The most significant changes were represented by a decrease in systemic vascular resistance and systemic arterial pressure, and an increase in heart rate and cardiac output.

Contractility indexes were not depressed in either group, and altered ventricular wall motion tended to improve to a slightly smaller degree than in patients treated with nitroglycerin.

The use of verapamil in patients with ischemic heart disease appears to be safe, and concern about the negative inotropic influences in humans no longer seems justified.
Influence of heart rate on systolic time intervals: Effects of atrial pacing versus dynamic exercise
Authors: Mertens H. M. , Mannebach H. , Trieb G. , Gleichmann U.
Published: February 2009

The effects of atrial pacing and dynamic exercise in the supine position on systolic time intervals (STI) were compared in 10 normals. In another group of 13 normals, the effect of exercise alone on STI was tested. A linear shortening of electromechanical systole (QS2) and left ventricular ejection time (LVET) with increasing heart rate was demonstrated with right atrial pacing and dynamic exercise in the frequency range between 60 and 140 beats/min. However, the shortening of LVET was significantly less (p<0.01) with exercise compared to pacing. This is explained by an increase in left ventricular stroke volume with exercise. The pre‐ejection period (PEP) was significantly (p<0.001) shortened with exercise, but there was no change with atrial pacing. Thus, changes in heart rate (HR) alone, without changes in the dynamic state of the heart, did not influence PEP.

It is suggested that PEP at rest should not be corrected for heart rate. The supine exercise regression equations for correction of heart rate for LVET and PEP differ from both the resting and the upright exercise regression equations. With exercise a frequency correction of STI using regression equations should be abandoned. Instead, uncorrected STI at standard heart rates (e.g., 100, 110, and 130 beats/min) should be taken for comparison. Heart rate standardization should be employed using the formula
Left ventricular end‐diastolic pressure in evaluating left ventricular function
Authors: Iskandrian A. S. , Segal B. L. , Hamid HAKKI A.
Published: February 2009

There are several factors that could affect the left ventricular end‐diastolic pressure. These include heart rate, preload, afterload, pericardial or pleural pressure, diastolic properties of the left ventricle, and the left ventricular inotropic state. Recognition of these factors appears important when considering the left ventricular end‐diastolic pressure as an index of left ventricular function.
Hyperkalemia‐induced bundle branch block and complete heart block
Authors: Ohmae M. , Rabkin S. W.
Published: February 2009

Hyperkalemia was associated with complete heart block in one patient that resolved by first showing right bundle branch block and marked left axis deviation (left anterior hemiblock). Then the right bundle branch block resolved, leaving the marked left axis deviation that was present before the hyperkalemic episode. Another patient with hyperkalemia had right bundle branch block with marked left axis deviation, both of which disappeared with correction of the hyperkalemia. These findings suggest that hyperkalemia can depress conduction in the His‐Purkinje system and raise the possibility that hyperkalemia may induce complete heart block distal to the atrioventricular junction.
Thallium stress myocardial imaging: An evaluation of fifty‐eight asymptomatic males
Authors: Nolewajka A. J. , Kostuk W. J. , Howard J. , Rechnitzer P. A. , Cunningham D. A.
Published: February 2009

The possible value of myocardial imaging with 201thallium as a screening procedure for the detection of latent disease has not been previously shown. Fifty‐eight asymptomatic men underwent exercise 201thallium imaging together with a risk score profile based on the Framingham criteria for predicting future coronary events. Six subjects (10%) developed perfusion defects compatible with myocardial ischemia. The risk score for the population with an abnormal test was 7.7±2.9%, compared to 2.0±2.2% (p<0.001) for those men with normal tests. Three of the subjects with abnormal scans underwent selective coronary arteriograms; all three had normal coronary arteries. During a 30‐month follow‐up, all individuals remained physically active and free of cardiac symptoms.
Long‐term maintenance therapy with prazosin in congestive heart failure
Authors: Mehta J. , Miles D. , Iacona M. , Conti C. R.
Published: February 2009

We evaluated the effects of long‐term maintenance therapy with oral prazosin (6‐20 mg, mean 14±2 mg/d) in 14 patients with congestive heart failure. The patients were followed for 6±1 months. Eleven of the fourteen patients reported subjective improvement. Two patients required increased diuretics because of gain in body weight. Systolic blood pressure showed a slight but sustained decrease suggesting persistent vasodilator effect. Reductions in echocardiographic left ventricular end‐diastolic (6.35±0.25‐5.88±0.25 cm, p<0.05) and end‐systolic (5.16±0.35‐4.73 ±0.28 cm, p<0.05) diameters were observed at 2 months. However, the cardiothoracic ratio on chest x ray was unaltered. Maximum exercise tolerance time increased in eight patients (57%) during prazosin therapy. Improvement in exercise tolerance time was observed in patients with most marked clinical improvement, suggesting presence of cardiac reserve. Two patients died suddenly after reporting subjective improvement. This study shows sustained clinical improvement in most patients with heart failure treated with oral prazosin.
Anomalous right ventricular muscle bundle: Clinical pitfalls and extracardiac anomalies
Authors: Danilowicz D. , Ishmael R.
Published: February 2009

Seven patients with anomalous right ventricular muscle bundle are presented to emphasize possible pitfalls in the clinical diagnosis as based on physical examination, chest x ray, and electrocardiogram. Echocardiography, on the other hand, revealed abnormalities in all four of the patients on whom the study was done. The echocardiogram was directly responsible for a change in diagnosis and referral for a cardiac catheterization in one patient who had been followed for 19 years with the clinical diagnosis of a small ventricular septal defect.
Myocardial injury and ck‐mb release during aortic valve surgery with selective coronary perfusion
Authors: Ström S. , Bendz R. , Olin C.
Published: February 2009

The postoperative serum activity of creatine kinase MB isoenzyme (CK‐MB) was studied in 25 patients undergoing isolated aortic valve replacement (Björk‐Shiley prosthesis). Hypothermia at 30° C and selective coronary perfusion (CP) were used for myocardial protection. Repeated electrocardiograms revealed no signs of perioperative myocardial infarction. In all patients, CK‐MB was detected in the serum. The CK‐MB as a percentage of total CK at peak CK‐MB [12±1 (mean±SEM)] was of the same magnitude as that found in acute myocardial infarction (AMI). Peak CK‐MB occurred 2±0 h after the end of surgery. Peak total CK occurred after 17±3 h, and the plasma half‐life for total CK was three times that of CK‐MB. Thus, the kinetics of serum CK differed from those in AMI, but were similar to those reported after coronary bypass operations. The release of CK‐MB, as well as of aspartate aminotransferase and thermostable lactate dehydrogenase, was related to the duration of aortic cross‐clamping (AC), with a marked increase after 90 min. In two subgroups with similar AC time, postoperative CK‐MB activity was higher in the subgroup with longer CP, indicating that CP as a method of myocardial protection may not be entirely beneficial.
Effects of oral hydralazine on rest and exercise hemodynamics in patients with aortic or mitral regurgitation and left ventricular dysfunction
Authors: Slosky D. A. , Hindman M. C. , Peter R. H. , Wallace A. G.
Published: February 2009

The hemodynamic effects of afterload reduction were studied at rest and during two levels of upright exercise in patients with aortic or mitral regurgitation and left ventricular dysfunction. Eleven patients underwent invasive hemodynamic monitoring before and after 50–70 mg of oral hydralazine was given every 6 h for 48 h. At rest, heart rate and mean arterial pressure after hydralazine were unchanged from control. During exercise, there was no significant change in heart rate, but mean arterial pressure fell significantly during the first level of exercise. Systemic vascular resistance was elevated before hydralazine and was significantly reduced after treatment at both exercise levels. After hydralazine, the resting oxygen consumption was significantly elevated at rest but was unchanged during exercise, the arteriovenous oxygen difference was significantly narrowed at both rest and exercise, and the pulmonary capillary wedge pressure was also significantly lower at both rest and exercise. In this select group of patients who are not candidates for surgical valve replacement, chronic afterload reduction with oral hydralazine may result in increased cardiac performance, decreased pulmonary congestion, reduced myocardial oxygen demands, and improvement in resting and/or exertional symptoms.
Effects of exercise on plasma viscosity in athletes and sedentary normal subjects
Authors: Letcher R. L. , Pickering T. G. , Chien S. , Laragh J. H.
Published: February 2009

To assess the immediate and long‐term effects of exercise on factors regulating blood flow, we measured plasma viscosity (ηp) and plasma renin activity (PRA) in 17 trained runners and 16 sedentary healthy subjects before and 10 min after graded treadmill exercise. Resting ηp was lower in runners primarily because of significantly lower fibrinogen concentration. Compared to nonrunners with similar 24‐h urine electrolyte excretion rates, runners were characterized by lower PRA at rest. In view of the overall correlation between heart rate and PRA before exercise, reduced adrenergic tone was probably a major factor contributing to the lower PRA in runners. After exercise, plasma viscosity and PRA exceeded control levels, and were similar in magnitude in runners and sedentary subjects. Changes in plasma viscosity were less than expected from the degree of hemoconcentration, primarily because enhanced fibrinolysis maintained fibrinogen level constant. To the extent that plasma viscosity affects viscous flow resistance, the results suggest that tissue perfusion and oxygen delivery rate at rest are greater in trained runners than in sedentary subjects, but these variables become similar after maximum exertion.
PISA: A noninvasive method in detection and quantification of acid‐induced myocardial infarction in dogs
Authors: Prasad K. , Gupta M. M.
Published: February 2009

Phase invariant signature algorithm (PISA), a new noninvasive technique, was used in the detection and quantification of acid‐induced myocardial damage in anesthetized dogs. The diagnostic capabilities of this method were compared with those of conventional electrocardiogram and biochemical markers, MB‐creatine phosphokinase (MB‐CPK) and lactic dehydrogenase (LDH1). Myocardial damage of varying degree was induced by injecting diluted sulphuric acid (0.01 to 0.10 ml) into the free wall of the left ventricle. Conventional ECG, wideband ECG for PISA analysis, blood samples for LDHI, and MB‐CPK were taken before and after 15, 30, 60, and 90 min of acid injection. The heart was removed at the end of 90 min for estimation of myocardial damage. PISA Index increased within 10–15 min of acid injection and remained elevated for the duration of the experiment (90 min). The increase in the PISA index was directly related to the extent of myocardial damage and the amount of acid injected. Although the conventional electrocardiogram detected large myocardial damage, it was unable to detect small myocardial damage. Also, most of initial changes in conventional ECG with large myocardial damage disappeared within 90 min, while the PISA index was still elevated to the maximum level. The MB‐CPK was not detected before or after myocardial damage. There was no significant change in the LDH1 at any time after myocardial infarction. These results suggest that the PISA technique is superior to the conventional ECG and the biochemical markers and would be a valuable diagnostic tool in the detection and quantification of incipient as well as advanced myocardial infarction.
Large mobile pedunculated left ventricular thrombus: Identification by two‐dimensional echocardiography
Authors: Chen C. C. , Webster G. W. , Morganroth J.
Published: February 2009

Two‐dimensional echocardiography has permitted the noninvasive detection and determination of the course of the natural history of left ventricular thrombus. In this report we cite an illustrative case of the development of a large pedunculated mobile left ventricular thrombus in the setting of idiopathic congestive cardiomyopathy. A fatal cerebral embolization occurred despite full‐dose intravenous anticoagulation before left ventricular thrombectomy could be performed. The presence of a large mobile pedunculated left ventricular thrombus in the setting of embolization and adequate anticoagulation may require surgical intervention.
Initial experience with a fully implantable, programmable, scanning, extrastimulus pacemaker for tachycardia termination
Authors: Nathan A. W. , Camm A. J. , Bexton R. S. , Hellestrand K. J. , Spurrell R. A. J.
Published: February 2009

Summary: A fully implantable automatic scanning pacemaker designed for tachycardia termination has been used in three patients with regular paroxysmal supraventricular tachycardia. The pacemaker recognizes tachycardia and delivers one or two extrastimuli which automatically scan inwards if tachycardia continues. A memory is incorporated to retain and immediately reuse a successful pacing sequence if tachycardia recurs. Ventricular pacing has been used in two patients and atrial stimulation in one. Although all had suffered frequent attacks of tachycardia after implantation no sustained episodes of tachycardia have been appreciated. No unwanted arrhythmias have been induced and drug treatment has been stopped in all three patients. Fully implantable scanning pacemakers which automatically recognize and revert tachycardia offer an effective and versatile form of treatment for recurrent paroxysmal tachycardias.
Wide vascular pedicle on thoracic roentgenogram in complete transposition of the great arteries
Authors: Schneeweiss A. , Blieden L. C. , Shem‐Tov A. , Fiegal A. , Neufeld H. N.
Published: February 2009

Summary: A narrow vascular pedicle on the thoracic roentgenogram is an important sign in the clinical diagnosis of complete transposition of the great arteries (Shaher, 1973a). Rarely a wide vascular pedicle is present in this condition, mainly due to associated lesions. The differential diagnosis in these cases is discussed, based on our experience with 14 cases.
The applicability of the signal averaging technique in clinical cardiology
Authors: Hombach V. , Braun V. , Höpp H.‐W. , Gil‐Sanchez D. , Scholl H. , Behrenbeck D. W. , Tauchert M. , Hilger H. H.
Published: February 2009

Summary: Since 1963 the signal averaging technique has been applied to improve the signal to noise ratio in highly amplified EKG registrations. Based on the experiences from the literature and the authors own laboratory, the applications of the signal averaging technique in clinical cardiology are reviewed: extraction and analysis of the fetal EKG and P‐wave variations, His bundle electro‐grams from the body surface (recovery rate 33–100% of cases), ventricular delayed depolarizations within the ST segment of the surface EKG (recovery rate, 40–90% of cases, depending on patient groups investigated), preatrial activity (sinus nodal potentials) from intra‐cardiac (recovery rate, 80–90% of individuals), or surface EKGs (recovery rate, 60% of patients), analysis of frequency components of surface EKG‐QRS complexes in patients with previous myocardial infarctions, and detection of low amplitude diastolic signals from surface phonocardiogram (recovery rate, 80% of cases). At present, advantages and limitations of the signal averaging technique may be appraised as follows: (1) sinus nodal potentials: S‐A conduction times may be more reliable than those obtained by the extra‐stimulus technique, since with averaging they are recorded during undisturbed sinus rhythm; direct recordings of changing S‐A blocks may be impossible due to the summation process; validation of sinus nodal potentials in man necessary, (2) A‐V nodal potentials: demonstration of true A‐V nodal rhythm rather than His bundle rhythm; possibly direct identification of abnormal pathways in A‐V nodal tachycardias; direct recordings of single A‐V nodal blocks impossible due to summation process; (3) surface His bundle potentials: follow‐up or screening of patients with A‐V nodal and particularly His‐Pur‐kinje‐system blocks; monitoring of antiarrhythmic drug therapy; atrial overlap in one‐third of cases; direct identification of higher degree A‐V nodal blocks impossible due to summation process (future developments may overcome this problem); (4) ventricular delayed depolarizations: possible identification of patients at high risk of sudden cardiac death; follow‐up of therapeutic measures like antiarrhythmic drug therapy or cardiac surgery (bypass grafting, aneurysmectomy); validation of delayed depolarizations from body surface by direct intracardiac and/or epicardial mapping necessary.
Mitral valve echocardiographic pattern within the left atrium
Authors: Motor M. , Schneeweiss A. , Neufeld H. N. , Grenadier E.
Published: February 2009

Summary: In a patient with a left atrial myxoma, the tumor adhered to the anterior leaflet of the mitral valve. This caused movement of the tumor's stalk in the left atrium in a pattern similar to that of a mitral valve in M‐mode echocardiography. An accurate diagnosis was made by cross‐sectional echocardiography and confirmed at surgery.
The value of grip test as an index of autonomic function in hypertension
Authors: Chrysant S. G.
Published: February 2009

Summary: The autonomic sympathetic adjustments to sustained handgrip, upright tilt, and the Valsalva maneuver, were tested in a total of 52 patients, 26 with labile and 26 with fixed essential hypertension. Sustained handgrip (SHG) increased arterial pressure, heart rate (HR), cardiac index (CI), and tension time index (TTI) (p<0.01), but had no effect on total peripheral resistance index (TPRI) and left ventricular ejection rate index (LVERI) in either group of patients. The response to upright tilt and the Valsalva maneuver was different in the two groups. Upright tilt in labile hypertensives increased diastolic arterial pressure (DAP), mean arterial pressure (MAP), HR, and TPRI (p<0.001), and decreased CI, stroke index (SI), and LVERI (p<0.01), and had no effect on systolic arterial pressure (SAP). In fixed hypertensives, it decreased SAP, MAP, CI, SI, and LVERI (p<0.001), increased HR (p<0.01), and had no effect on DAP and TPRI. The diastolic pressure overshoot of the Valsalva maneuver was attenuated in fixed hypertensives compared to labile hypertensives (p<0.001). Also, when the percent changes from control in diastolic and mean arterial pressure, heart rate, and total peripheral resistance index after sustained handgrip and upright tilt between the two groups of patients were compared, only upright tilt brought out the differences between the two groups. The results of this study indicate that upright tilt and the Valsalva maneuver are better predictors of autonomic function in hypertension than the grip test.
Tissue and coronary venous pH in ischemic canine myocardium
Authors: Cobbe S. M. , Parker D. J. , Poole‐Wilson P. A.
Published: February 2009

Summary: The relationship between changes in myo‐cardial tissue pH and local coronary venous pH during and after transient occlusion of the left anterior descending artery was investigated in 6 open chested an‐esthesized dogs. Tissue pH was recorded with a needle pH electrode, and coronary venous pH with a specially designed catheter tip pH electrode. Myocardial tissue pH fell steadily after coronary occlusion, and had fallen by 0.107±0.043 pH units (mean±SD, n=12 occlusions) after 150 s. On reperfusion there was a further small fall in tissue pH to 0.138±0.035 units before tissue pH returned to control. In contrast, the fall of coronary venous pH during ischemia was small (0.15±0.027 after 150 s, n=12 occlusions). Within 5 s of reperfusion, a large fall in venous pH occurred, reaching a maximum of 0.150±0.072 at 20–30 s after reperfusion.

During ischemia changes in tissue pH are poorly represented by changes in coronary venous pH. The size of the early change of venous pH during the reperfusion washout of retained metabolites is a better estimate of the fall of tissue pH. Measurement of metabolites in the coronary sinus of man during the washout after the end of an ischemic intervention such as atrial pacing is superior to measurements performed during pacing in providing biochemical evidence of myocardial ischemia.
Rheumatic Heart Disease and Pregnancy in Nigerian Women
Authors: Cole T. O. , Adeleye J. A.
Published: February 2009

Summary: The early onset of rheumatic fever and rapid progression to severe and incapacitating chronic valve disease, as in other developing tropical countries, has been repeatedly highlighted in Nigeria. Of interest is the fact that the peak frequency of age distribution is in the early child‐bearing age. This study was undertaken to evaluate the clinical course of 44 pregnancies in 32 Nigerian women between 16 and 38 years of age (mean 27), with rheumatic heart disease. The patients received careful clinical assessment on follow‐up at 1 to 4 week intervals depending on grade of symptoms and stage of gestation. All deliveries were conducted in the hospital and patients were clinically reassessed 6 months after delivery. The key to grading of symptoms was the New York Heart Association functional classification, coordinated with findings on detailed clinical examination. The majority of the cases were gravida 3 but closely followed by primigravidae. Mitral valve disease with dominant incompetence was the commonest valve lesion. Nevertheless, acute pulmonary edema (11 cases), the cause in 2 of the 3 maternal deaths, was the most frequent complication. Congestive heart failure occurred in 7 cases, and infective endocarditis in 4 cases. The only patient with mitral valve prosthesis was on warfarin prophylaxis and had 2 of the 3 stillbirths in the series. On clinical reassessment 6 months later, there was evidence of progression of functional state in 8, and interestingly, more maternal deaths occurred in less than a year. These findings are no doubt related to the presently limited medical facilities, inadequate socioeconomic and public health standards, and the need for health education in the country, and not excluding the seemingly rapid progression of rheumatic heart disease itself. In light of such circumstances, the relevant aspects of the accepted program of management in the more developed temperate countries would need to be meaningfully adjusted and suggestions have been made to this effect.
Influence of Myocardial Substrate Utilization on the Oxygen Consumption of the Heart
Authors: Kahles H. , Hellige G. , Hunneman D. H. , Mezger V.‐A. , Bretschneider H. J.
Published: February 2009

The effect of changing myocardial metabolism from predominantly lipid to predominantly carbohydrate utilization on myocardial oxygen consumption (v̇O2) was studied in 10 closed‐chest dogs. Oxygen saving potency df different metabolic interventions was quantified over a wide hemodynamic range by comparing the directly determined v̇O2 with the hemodynamic parameter total left ventricular energy demand (Et), which correlates closely under control conditions with v̇O2 (r = 0.98). Stimulation of carbohydrate metabolism by addition of glucose and β‐pyridyl carbinol or by activation of pyruvate dehydrogcnase with di‐chloroacetate (DCA) shifted the cardiac respiratory quotient during β‐stimulation from 0.73 to 1.00 and 0.89, respectively, the nonesterified fatty acid/albumin ratio decreased from 4.0 to 0.5, or remained unchanged with DCA, and v̇O2 was reduced by 25 and 16%, respectively. Therapeutic approaches aimed at decreasing v̇O2 by changing substrate utilization are discussed.
Mid‐Diastolic Aortic Valve Opening in Bacterial Endocarditis of Aortic Valve
Authors: Ravindra Nathan M. P. , Arora R. , Rubenstein H.
Published: February 2009

Summary: Echocardiographic features of acute aortic regurgitation resulting from bacterial endocarditis have been well documented (Nathan et al., 1980; Weaver et al., 1977; Wray, 1975a), and include thick shaggy echoes from aortic valve in diastole, fine diastolic flutter of aortic valves suggestive of rupture of cusps, and premature closure of mitral valves. Echocardiography being a sensitive noninvasive technique for detecting aortic valve vegetations is heavily relied on for earlier diagnosis and prompt therapy of these patients. Prognosis of echocardiographically positive endocarditis is known to be worse than for echo‐negative patients. The following case is being presented because of an unusual echocardiographic manifestation with mid‐diastolic aortic valve opening secondary to flail aortic valve from staphylo‐coccal endocarditis of the aortic valve.
Obstructive Cardiomyopathy in a Male Dwarf with Cryptorchidism
Authors: Fatourechi V. , Sheikhzadeh A. H. , Gavam M.
Published: February 2009

Summary: Obstructive cardiomyopathy has been reported in cases of male and female Turner phenotype with normal chromosomes. We report here a case of a male dwarf with bilateral undescended testes and bi‐ventricular obstructive cardiomyopathy. Clinical features included choreoathetoid movements, chorioretin‐itis, bilateral nystagmus, and unusual red color of the hair, associated with some features of Turner phenotype. Endocrine studies were normal except for a lack of thy‐rotrophic stimulating hormone (TSH) response to thy‐rotrophic releasing hormone (TRH) stimulation. Pro‐pranolol removed the gradient during cardiac cathe‐terization and relieved the exertional chest pain clinically.
Computer enhanced digital angiography
Authors: Vas R. , Diamond G. A. , Levisman J. A. , Nakano F. H. , Neidorf B. S. , Rose R. M. , Whiting J. S. , Forrester J. S.
Published: February 2009

Summary: A new computer image enhancement technique was employed on cardiac images of 10 dogs and 7 patients to demonstrate the feasibility of an on‐line automatic delineation of the left ventricular endocardial silhouette with a peripheral venous injection of contrast material while simultaneously reducing the x‐ray dosage. This technique employs a very fast analog‐to‐digital conversion system capable of digitizing on‐line video frames. By storing and continuously updating the first 30 video frames and then subtracting each incoming frame from this memory, most of the background is eliminated leaving only the contrast filled ventricle. Using calibrated densitometric measurements, we found that iodine concentrations in the human left ventricle following venous injection of 40 ml Renografin®‐76 (25 ml/s), peaked at 4.3±0.3 mg/ml (mean±SD) compared to 14.8±0.8 mg/ml following direct injection of 40 ml at 13 ml/s (p<0.001). The computer enhanced venous‐injected images had an optical contrast 14 times greater than that of the unenhanced direct left ventric‐ulogram. This increase in optical contrast provided unambiguous subjective definition of the endocardial borders. This technique is applicable to both central and peripheral contrst injection whereby high quality images can be obtained at approximately 98% reduction in radiation (5 mA, 65–85 kV), allowing performance of serial studies.