bluuebunny/crossref_metadata_2025 huggingface dataset:
On Trusting Wikipedia
Authors: Magnus P. D.
Published: February 2009

Given the fact that many people use Wikipedia, we should ask: Can we trust it? The empirical evidence suggests that Wikipedia articles are sometimes quite good but that they vary a great deal. As such, it is wrong to ask for a monolithic verdict on Wikipedia. Interacting with Wikipedia involves assessing where it is likely to be reliable and where not. I identify five strategies that we use to assess claims from other sources and argue that, to a greater of lesser degree, Wikipedia frustrates all of them. Interacting responsibly with something like Wikipedia requires new epistemic methods and strategies.
A constructional approach to lexicalization processes in the history of English: Evidence from possessive constructions
Authors: Trousdale Graeme
Published: February 2009

This article is concerned with aspects of lexicalization in the history of English from the perspective of Construction Grammar (CxnG). I show how constructional approaches can account for both grammaticalization and lexicalization within a unified framework, basing my argument around the two kinds of input to lexicalization which Brinton & Traugott (2005 : 96) identify: syntactic constructions and word formation patterns. In lexicalization, linguistic forms that initially participate in an abstract schematic macro- or meso-construction, become idiosyncratic micro-constructions, whereas in grammaticalization an idiosyncratic micro-construction comes to participate in a more schematic meso- or macro-level construction.

The main part of the paper is devoted to a discussion of the evolution of what Taylor (1996) has described as possessive compounds, such as driver's license, in the history of English. I specifically consider how the CxnG framework can explain the development of form-meaning mismatches, conventionalization, and the loss of internal constituency, in lexicalization. The data suggest that a constructional approach can account for the two stages of lexicalization (grammatical to lexical, less lexical to more lexical) in a way parallel to the two stages of grammaticalization (lexical to grammatical, less grammatical to more grammatical).
A Survey on Position-Based Routing Algorithms in Wireless Sensor Networks
Authors: Jin Zhang , Jian-Ping Yu , Si-Wang Zhou , Ya-Ping Lin , Guang Li
Published: February 2009

Wireless sensor networks (WSN) have attracted much attention in recent years for its unique characteristics and wide use in many different applications. Routing protocol is one of key technologies in WSN. In this paper, the position-based routing protocols are surveyed and classified into four categories: flooding-based, curve-based, grid-based and ant algorithm-based intelligent. To each category, the main contribution of related routing protocols is shown including the relationship among the routing protocols. The different routing algorithms in the same category and the different categories are compared based on popular metrics. Moreover, some open research directions in WSN are also discussed.
“It’s All We Got Left”. Why Poor Smokers are Less Sensitive to Cigarette Price Increases
Authors: Peretti-Watel Patrick , Constance Jean
Published: February 2009

In France, between 2000 and 2008, concurrently to the increase in cigarette price, we observed an increasing social differentiation of cigarette smoking: smoking prevalence decreased among executive managers and professional occupations, it remained stable among manual workers, and it increased among the unemployed. Poor smokers were heavier smokers, they were more frequently tobacco-dependent, and they were more prone to smoke automatically or to reduce “negative feelings”. In-depth interviews provided a more comprehensive insight into poor smokers’ motivations: they were aware of their addiction, but they also talked about the pleasure they get from smoking, and they highlighted the essential needs satisfied by smoking: stress relief, cheap leisure, compensation for loneliness, break-up or redundancy… Acknowledging the functional aspects of smoking experienced by poor smokers helps to understand why increasing the cigarette price is unlikely to deter many poor smokers from smoking.
Application of Bayesian Methods to Exposure Assessment of Area Concentrations at a Rubber Factory
Authors: He Yonghua , Liang Youxin , Fu Hua
Published: February 2009

The present study estimated area concentrations of airborne benzene in several workshops using Bayesian methods based on available historical measurements. A rubber products factory utilizing benzene was investigated. Historical measurements of benzene concentrations, expert experiences, and deterministic modeling were utilized in a Bayesian Method to estimate area concentrations. Historical concentrations (n=124) were available with the geometric mean of 15.3 mg/m3. The geometric mean of the current field measurements on the workstations ranged from 0.7 to 89.0 mg/m3. One of the seven historical geometric means by work locations significantly differed from the field measurements for equivalent locations, but none of the geometric means of Bayesian estimates were significantly different from the field measurement results. The Bayesian methods based on the historical measurements appeared to be a useful tool for more closely estimating area concentrations shown by field data than that predicted only using historical measurements.
Anti-inflammatory Activity and PGE2 Inhibitory Properties of Novel Phenylcarbamoylmethyl Ester-Containing Compounds
Authors: Barsoum Flora , Georgey Hanan , Abdel-Gawad Nagwa
Published: February 2009

A variety of 4-(un)substituted phenylcarbamoyl methyl ester-containing compounds 3a-d, 5a-d and 7a-d were synthesized via reaction in N,N-dimethylformamide of (un)substituted chloroacetanilides 2a-d with the potassium salts of ibuprofen (1), naproxen (4) and N-acetylanthranilic acid (6). Moreover, other 4-(un)substituted phenylcarbamoylmethyl ester-containing compounds 10a-d were synthesized via the attack of (un)substituted chloroacetanilides 2a-d on one of the carboxylic acid groups of the potassium salt of 4-(2-carboxyethylcarboxamido)benzoic acid (8)in N,N-dimethylformamide, with subsequent cyclization of the other one giving finally a pyrrolidinone structure. Anti-inflammatory properties of the synthesized compounds were evaluated in vivo utilizing a standard acute carrageenan-induced paw oedema method in rats and the most promising prepared anti-inflammatory active agents were evaluated for ulcerogenic liability in rats using ibuprofen and naproxen as reference standards in both screenings. PGE2 inhibitory properties of the highly promising anti-inflammatory agents synthesized and low gastric ulcerogenic liabilities were tested with a PGE2 assay kit technique.
Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate
Authors: Ahirwal Gautham Kumar , Mitra Chanchal   K.
Published: February 2009

We have studied the direct electrochemistry of horseradish peroxidase (HRP) coupled to gold nanoparticles (AuNP) using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i) glutathione and (ii) lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications
Molecular cloning and characterization of Bombyx mori CREB gene
Authors: Song Hongsheng , Sun Yue , Zhang Yang , Li Muwang
Published: February 2009

The cAMP response element binding protein (CREB), as one of the best characterized stimulus‐induced transcription factors, plays critical roles in activating transcription of target genes in response to a variety of environmental stimuli. To characterize this important molecule in the silkworm, Bombyx mori, we cloned a full‐length cDNA of CREB gene from B. mori brains by using RACE‐PCR. The sequence of B. mori CREB (named BmCREB1) gene contains a 88 bp 5′ UTR, a 783 bp open reading frame (ORF) encoding 261 amino acids and a 348 bp 3′ UTR. The deduced BmCREB amino acid sequence has 56.7% and 37.2% homology with CREB from Apis mellifera carnica and Drosophila melanogaster, respectively. The primary structure of the deduced BmCREB1 protein contains a kinase‐inducible domain (KID) and a basic region/leucine zipper (bZIP) dimerization domain which exisits in all CREB family members. Genomic analysis showed there are 9 exons and 5 introns in B. mori CREB genome sequences. We identified three different isoforms of BmCREB (BmCREB1, BmCREB2 and BmCREB3) through alternative splicing in C terminal. In addition, the expression of BmCREB in different developmental stages was investigated by using quantitative real‐time PCR in both diapause and non‐diapause type of B. mori bivoltine race (Dazao). BmCREB transcripts showed two peaks in embryonic stage and pupal stage in both types of bivoltine race. However, consistently higher expression of BmCREB was found throughout the developmental stages in the diapause type than in the non‐diapause type. These results suggest that BmCREB is involved in the processs of diapause induced by environmental factors. © 2009 Wiley Periodicals, Inc.
Effects of heat shock on ovary development and hsp83 expression in Tribolium castaneum (Coleoptera: Tenebrionidae)
Authors: Xu Jingjing , Shu Juan , Qiu Xiaotian , Wang Zhipeng , Zhao Fuping , Zhang Zhe , Zhang Qin
Published: February 2009

Heat shock affects reproductive performance in insects including Tribolium castaneum. In this study, the effects of heat shock on ovary development and hsp83 expression in T. castaneum were investigated. Two lines of T. castaneum, H line and C line, from the same base population were established and maintained for five successive generations. In each generation, the newly hatched beetles (within 3 h after eclosion) in the H line were treated with a heat shock at 40°C for 1 h, and those in the C line were raised at normal temperature (30°C) as control treatment. Four traits related to ovary development were measured for the beetles of the fifth generation: days from eclosion to laying the first eggs (To), days from eclosion to laying the first hatchable eggs (Th), ovariole size on the third day after eclosion, and pupal mass of their offspring. The results showed that the beetles of the H line had a significantly longer pre‐oviposition period (0.6 more days) and smaller ovariole size than those of the C line. No significant difference in pupal mass was observed. Applying heat shock to the offspring of the fifth generation of both lines led to significantly higher hsp83 expression in offspring of the C line than in offspring of the H line. Within each line, the hsp83 expression level in offspring with heat shock was significantly higher than that of offspring without heat shock, but the difference in the C line was much larger than that in the H line. We infer from these results that a tradeoff between heat resistance, registered as hsp83 expression, and ovarian development operates under heat stress in T. castaneum. 2009 Wiley Periodicals, Inc.
Natural course of a prolonged pr interval and the relation between pr and incidence of coronary heart disease. A 7‐year follow‐up study of 1832 apparently healthy men aged 40–59 years
Authors: Erikssen J. , Otterstad J. E.
Published: February 2009

During a baseline cardiovascular survey PR was measured in a strictly standardized way in 1832 men aged 40–59 years, free from coronary heart disease (CHD). Of 1758 men still alive, 1585 underwent an identical follow‐up study 7 years later. A total of 1570 were in sinus rhythm. The following findings were made: (1) Baseline and follow‐up prevalence of a prolonged PR (≥0.22 s) was identical (5.3 vs. 5.4%). (2) Only 60% of restudied men with a prolonged PR also had prolonged PR at follow‐up. (3) Only 1 of 98 with a prolonged baseline PR had a more advanced AV block at follow‐up, whereas an additional 4 had conditions which might influence the AV node (1 Bechterew' disease and 3 mild aortic valve stenosis). (4) The incidence of all CHD events found during the follow‐up study (CHD deaths, myocardial infarction, angina pectoris, and pathologic exercise ECGs) was moderately but significantly lower in men with a prolonged PR than among men with a PR ≤0.21 s. Thus a prolonged PR is rarely an indicator of impending, more severe conduction disturbances; it is mostly a benign, functional finding in middle‐aged men free from overt heart disease and is not positively associated with CHD. Rather PR may be moderately and inversely associated with latent CHD.
Effects of dobutamine on left ventricular performance and myocardial metabolic demands in patients with ischemic heart disease
Authors: Cote P. , Bourassa M. G. , Tubau J. F. , Enjalbert M. , Vandormael M.
Published: February 2009

Sixteen patients with coronary artery disease undergoing cardiac catheterization were studied. Eleven had previous infarcts and the patients were divided into two groups: In group I were 7 patients with no left ventricular dysfunction, no increase in ventricular size, or symptoms of congestive failure; group II included 9 patients with ventricular dysfunction, increased ventricular size, and 7 of the 9 had congestive failure. Each patient underwent a continuous infusion of dobutamine from 2.5 to 10 μUg/kg min‐1 with dosage increments of 2.5 μUg/kg at 15‐minute intervals. Systemic and coronary hemodynamic measurements were obtained at the end of the 5 and 10 μUg/kg min‐1 infusion doses. Left ventricular performance improved (higher cardiac index, left ventricular stroke work index and mean systolic ejection rate, and lower left ventricular end‐diastolic pressure), while heart rate, mean arterial pressure, and coronary sinus blood flow increased after dobutamine in the 16 patients. While patients in both groups had a rise in cardiac index, a reduction in left ventricular end‐diastolic pressure, an unchanged mean arterial pressure and a rise in coronary blood flow, only patients in group I had a significant increase in heart rate, and only patients in group II had significant increases in left ventricular stroke work index and mean systolic ejection rate, and a significant reduction in systemic vascular resistance. Left ventricular oxygen consumption did not increase significantly in either group. However, 5 patients showed a decreased myocardial lactate extraction after 10 μUg/kg min‐1 of intravenous dobutamine, 3 from group I and 2 from group II. These 5 patients had less ventricular dysfunction than patients with a normal lactate response to intravenous dobutamine. We conclude that the improvement in left ventricular performance observed after dobutamine administration in patients with ischemic heart disease is not usually associated with a major increase in left ventricular oxygen consumption or with marked aggravation of myocardial ischemia. This appears to be particularly true in patients with relatively severe left ventricular dysfunction.
A dose response study with oral prenalterol in patients with chronic congestive cardiac failure
Authors: Hendry W. G. , Comerford M. B. , Besterman E. M. M.
Published: February 2009

Prenalterol is an orally active cardioselective beta agonist, with a long half‐life. Previous studies have confirmed its inotropic activity following intravenous infusion in patients with heart failure. It has little chronotropic activity and no significant arrhythmogenicity. We have studied the response to sustained‐release oral prenalterol given over four weeks at doses of 20, 40, 100, and 200 mg daily in 10 patients with New York Heart Association class II and III heart failure due to ischemic heart disease. All were in sinus rhythm and already receiving diuretics and digoxin. The drug was well tolerated and without side effects. Nine patients showed a dose‐related improvement in their exercise tolerance as measured on the treadmill, up to a dose of 100 mg daily, with a significant increase in estimated oxygen uptake. There was a dose‐related reduction in maximum heart rate, systolic blood pressure, and rate‐pressure product during exercise, which is suggestive of a reduction in myocardial oxygen consumption. We conclude that prenalterol improves exercise tolerance without any significant cardiovascular or other side effects, and produces a clinically relevant and sustained improvement in patients with chronic heart failure. M‐mode echocardiographic measurements of left ventricular dimension and function at rest did not show any change during the study.
Adverse reactions to protamine sulfate following cardiac surgery
Authors: Holland C. L. , Singh A. K. , Mcmaster P. R. B. , Fang W.
Published: February 2009

We report four patients who developed severe adverse reactions to protamine sulfate following cardiac surgery. Two types of reactions were seen. First, an immediate anaphylaxis which is a complement‐dependent IgG antibody‐mediated reaction. In the literature, 80% of patients who had similar reactions have had previous exposure to protamine. All patients adequately tested had positive skin tests and there is 6% mortality. The second reaction to protamine during cardiac surgery is characterized by delayed onset and profound vascular damage presenting as noncardiogenic pulmonary edema or total vascular collapse with prolonged hypotension and anasarca. These patients have negative skin tests and in our studies, no evidence of antibody mediated reaction, suggesting some other mechanisms may play a part. The mortality is high (30% of patients reported) and survivors have significant morbidity.
Long‐term oral treatment with high doses of verapamil in lone atrial fibrillation
Authors: Johansson P.‐A. , Bertil OLSSON S.
Published: February 2009

It has earlier been shown that verapamil given intravenously or orally in sufficiently high single doses, may result in regular ventricular rhythm in patients with atrial fibrillation. We have analyzed whether this effect of verapamil can be utilized in long‐term oral treatment. Eleven patients with lone atrial fibrillation were studied. Verapamil was given in gradually increasing doses from 40 mg three times a day to 320 mg three times a day, either alone or in combination with digoxin. Resting ECG was recorded and supine and standing blood pressures were measured on each dose level. When the patients were treated with verapamil alone, only a slight decrease in heart rate was noted, while during combined treatment with verapamil and digoxin a more marked heart rate decrease occurred with increasing doses of verapamil. The variation coefficient of the RR interval, a sign of ventricular regularity, decreased during verapamil treatment regardless of whether or not digoxin was also taken. A dose‐dependent blood pressure decrease was noted during verapamil treatment.

Side effects were common and led to discontinuation of the attempted protocol in all patients. Three patients were unexpectedly converted to stable sinus rhythm. Five patients improved subjectively, with a marked decrease in the sensation of palpitations during intake of increasing doses of verapamil. The study indicates that chronic oral treatment with verapamil may sometimes relieve the subjective sensation of palpitations in patients with atrial fibrillation. Side effects do, however limit the value of this mode of treatment in the majority of patients.
Unusual form of bilateral partial anomalous pulmonary venous drainage
Authors: Bexton R. S. , Banim S. O. , Rees G. M. , Rees R. S. O.
Published: February 2009

A 23‐year‐old man with known valvular pulmonary stenosis was found to have a very unusual form of bilateral partial anomalous pulmonary venous drainage. The venous drainage from the upper parts of both lungs was anomalous, draining from the left lung via a persistent left‐sided superior vena cava and from the right lung directly into the right atrial/right superior vena caval junction. The venous drainage from the lower parts of both lungs was normal. The embryological pathogenesis of the defect is discussed.
Competitive blood flow in the coronary circulation simulating progression of proximal coronary artery disease after saphenous vein bypass surgery
Authors: Miller W. P. , Dash H.
Published: February 2009

We report a case of competitive blood flow in the left coronary circulation after saphenous vein bypass grafting that resulted in the apparent progression of a proximal stenosis to total occlusion at coronary angiography. Repeat angiography with careful attention to catheter position and adequate injection of contrast agent demonstrated the actual anatomy and showed that there was no postoperative change in the native coronary circulation. The true incidence of progression of proximal coronary disease after saphenous vein bypass surgery is unknown, and reported figures may be falsely elevated because of unrecognized competitive flow patterns simulating obstruction.
Migration of retained pacemaker electrodes
Authors: Shaw R. J. , Chambers J. B. , Oldershaw P. J.
Published: February 2009

Two cases of migration of retained pacemaker electrodes are described. The first presented as an unusual cause of deep vein thrombosis while the second was asymptomatic and detected by routine chest x‐ray. Both made a good recovery, the first with surgery and the second with the fragment left in situ. A review of the world literature revealed only 13 other such cases. Of the total of 15 cases four are known to have died. In these patients no relationship was found between morbidity and the site of migration or associated infection and/or thrombosis. However surgical treatment appeared to be associated with a better prognosis.
Mitral valve prolapse related to geometrical changes of the heart in cases of progressive muscular dystrophy
Authors: Yazawa Y.
Published: February 2009

The significance of geometrical changes of the heart for the development of mitral valve prolapse (MVP) was studied by echocardiograms and chest x‐ray films in 58 cases of progressive muscular dystrophy (PMD). The incidence of MVP was significantly higher (p<0.001) incases where the thoracic spine was straight or lordotic compared with cases of kyphotic thoracic spine. The flattening of the thorax associated with deformation of the thoracic spine was correlated with the left atrial dimension and left ventricular dimension (r=0.62, r=0.37, respectively; p<0.001), and MVP developed predominantly in cases with flattened thorax and small left atrial or left ventricular dimensions. The left atrial and left ventricular dimensions were significantly smaller in cases with MVP compared to cases without MVP (p<0.001, p<0.005, respectively). When both the left atrial and the left ventricular dimension shortened to certain levels, MVP was observed in almost all cases. From these results, it was suggested that the portion from the left atrium to the left ventricle was pressed by the forward bending of the thoracic spine, and the subsequent geometrical changes of the mitral ring and the left ventricle could produce redundancy of the chorda tendinea of the mitral valve, resulting in the occurrence of MVP.
The exercise response in idiopathic dilated cardiomyopathy
Authors: Kirlin P. C. , Das S. , Zijnen P. , Wijns W. , Domenicucci S. , Roelandt J. , Pitt B.
Published: February 2009

In order to more clearly define the exercise response of idiopathic dilated cardiomyopathy (IDC), 20 patients in this study with strictly defined IDC were evaluated with radionuclide ventriculography and invasive hemodynamic monitoring. Severe cardiovascular impairment was present at rest, and peak supine exercise produced progressive left ventricular (LV) dilatation in both diastole and systole (mean±SEM from 172±14 to 212±22 ml/m2 at end‐diastole and from 137± 14 to 170±22 ml/m2 at end‐systole; both p<0.03). There were marked increases in LV and right ventricular filling pressure (from 17±2 to 36±3 mmHg and from 7±2 to 15±2 mmHg, respectively; both p<0.0001) and increased pulmonary artery pressure. Mean LV ejection fraction did not change significantly with exercise (22±2 to 23±3%; p>0.8), but individual patients demonstrated substantial variability. Cardiac output rose less than in normals and increases were brought about primarily by subnormal heart rate increases. High resting and exercise systemic and pulmonary vascular resistance were indicative of limited vasodilator reserve. Despite marked hemodynamic abnormalities, 10 of the 20 subjects had well preserved exercise capacity (≥ 12 min exercise duration). These patients as a group had significantly lower resting heart rate and higher exercise cardiac output and lower exercise systemic vascular resistance. However, they did not differ from the other patients with respect to resting LV function. Thus, the exercise response in IDC has specific characteristics that distinguish it from normal and from the exercise response of other causes of LV dysfunction. An interesting subset of patients with IDC has well preserved exercise capacity associated with greater chronotropic and vasodilator reserve. This finding suggests less sympathetic activation in these subjects.
Relationship between electrocardiographically estimated infarct size and clinical findings in anterior myocardial infarction
Authors: Herlitz J. , HJALMARSON Å.
Published: February 2009

In 292 patients with anterior myocardial infarction (MI) and no previous MI the electrocardiographically estimated infarct size was correlated with clinical findings during hospitalization and 3‐month follow‐up. Patients with ECG‐defined transmural MI had a higher incidence of different types of complications, such as congestive heart failure (CHF), hypotension, pericarditis, and a longer duration of hospitalization than patients with nontransmural MI. In a subgroup including 182 patients of the total series, a precordial map containing 24 electrodes was used. The sum of R waves (ΣR), the sum of Q waves (ΣQ), the number of Q waves, and ΣR‐ΣQ were calculated 4 days after arrival in hospital to estimate the size of infarction. There was generally a correlation between these ECG variables and different clinical findings, such as incidence of CHF, hypotension, pericarditis, and the duration of hospitalization. It is concluded that the ECG determined infarct size in anterior MI in a majority of patients correlates with the incidence of different types of complications in acute myocardial infarction. In the individual patient, however, the risk of developing complications cannot be predicted by ECG changes.
The inaccuracy of aortic valve systolic flutter as a screening test for significant aortic stenosis
Authors: Vacek J. L. , Phelix J. , Rycyna J. L.
Published: February 2009

The noninvasive assessment of the severity of aortic stenosis is difficult. A recent description of systolic flutter of aortic valve leaflets as a screening test for severe aortic stenosis was applied to a group of patients who had undergone catheterization. As opposed to the previous report, we found this an inaccurate, nonspecific, and insensitive aid for the differentiation of significant versus nonsignificant aortic stenosis; and feel that its validity should be studied further before wide application.
Aortic dilatation resulting in chronic aortic regurgitation and complicated by aortic dissection in a patient with turner's syndrome
Authors: Goldberg S. M. , Pizzarello R. A. , Goldman M. A. , Padmanabhan V. T.
Published: February 2009

A patient with XO Turner's syndrome with a 12‐year history of progressive aortic root dilatation resulting in chronic aortic regurgitation is presented. Her case is unique in that it occurred in the absence of coarctation of the aorta, bicuspid aortic valve, or hypertension. Idiopathic dilatation of the aorta may be an additional risk factor to the development of aortic dissection in the setting of Turner's syndrome.
Blood flow measurements in the fetal descending aorta: Technique and Clinics
Authors: Tonge H. M. , Struijk P. C. , Wladimiroff J. W.
Published: February 2009

A combination of two‐dimensional and realtime pulsed‐Doppler ultrasound provides a noninvasive method of measuring human fetal blood flow without side effects. By not altering the physiological conditions of the fetus, it minimizes external stimuli that might affect blood flow. However, due to the inaccessibility of the vessels under investigation, errors from the ultrasound technique arise and these are still being assessed. Studies of fetal blood flow suggest that the fetal circulation has a low peripheral resistance and that the increase in blood flow found with increasing gestational age is due predominantly to the increase in the actual dimensions of the fetal vasculature. Investigations in abnormal pregnancies, such as small‐for‐dates and those with cardiac arrhythmias have shown that the fetal cardiovascular system is capable of compensating efficiently to maintain normal physiological conditions, but only within the limits defined by the Frank Starling mechanism.
Echocardiographic assessment of left ventricular diastolic function in a normal population and a group of patients with myocardial hypertrophy
Authors: Bryhn M.
Published: February 2009

In order to study left ventricular diastolic function, digitized M‐mode echocardiograms of the free wall endocardium were analyzed. A population of 117 healthy individuals was compared with a group of 22 patients with myocardial hypertrophy due to aortic stenosis (AS), and a group of 21 with hypertrophic cardiomyopathy (HCMP). The time constant Te of endocardial retraction in normals (66±13 ms) differed significantly from Te in the patients (AS, 105±23 ms, p<0.001; HCMP, 113±31 ms, p<0.001). Peak velocity of endocardial retraction (peak neg. dEnd/dt, in the normals 8.6±2.7 s‐1) did not differ between normals and patients (AS, 7.0±2.3 s‐1; HCMP, 7.3±2.4 s‐1). Fractional shortening (FS) of the internal diameter, a parameter of left ventricular systolic function, tended to be higher in the AS patients than in the normal group, but was on the average significantly increased in the group of HCMP. However, most patients in the hypertrophic groups had FS within normal limits ±2 SD. The discrepancy between normal or supernormal systolic function and a pathological prolonged time constant Te in myocardial hypertrophy demonstrates the importance of diastolic parameters in left ventricular characterization. Te is a useful parameter of left ventricular diastolic function which can be provided noninvasively from echocardiographic M‐mode curves of the free wall endocardium.
Different effects of interventions suppressing free fatty acid metabolism on myocardial ischemia
Authors: Kahles H. , Hellige G. , Hunnemann D. H. , Junggeburth J. , Kochsiek K.
Published: February 2009

We studied the effects of different metabolic interventions, which stimulate oxidative myocardial carbohydrate metabolism, on ischemic stress during repeated coronary occlusions of three minutes in open‐chest dog hearts. Increase of glucose concentration in plasma and decrease of peripheral lipolysis by glucose‐insulin‐potassium (n=6) had no substantial beneficial effects on myocardial damage indicated by hemodynamic, electrocardiographic, and metabolic parameters. Infusion of lactate and pyruvate (10 mM, n=6) was detrimental. Only activation of pyruvate dehydrogenase by dichloroacetate (n=6) without influence on plasma osmolality reduced epicardial ST‐segment elevations (‐42%) and myocardial release of potassium (‐36%), phosphate (‐58%), and lactate (‐39%). Elevations of plasma osmolalities by 10 and 20 mOsm with the metabolically inert mannitol increased ECG changes, functional loss and release of potassium, phosphate, and lactate during ischemia in our model. It is suggested, that the oxygen‐saving potency of metabolic interventions can exert univocal beneficial effects in experimental and in clinical conditions only when systemic hyperosmolality and hypervolemia are avoided.
Acute myocarditis associated with transient marked myocardial thickening and complete atrioventricular block
Authors: Liao P.‐K. , Seward J. B. , Hagler D. J. , Driscoll D. J.
Published: February 2009

A 17‐day‐old male infant with acute myocarditis developed complete heart block and cardiogenic shock. In addition, extensive concentric thickening of the left ventricular walls and diminution of the ventricular cavity were demonstrated by serial echocar‐diography. The echocardiographic findings mimicked a nonobstructive hypertrophic cardiomyopathy. However, the wall thickness gradually returned to normal, coincident with clinical improvement. This unusual myocardial thickening may have resulted from myocardial edema or cellular infiltration. Its relationship to high‐dose steroid therapy is unclear.
Left atrial myxoma associated with rheumatic mitral stenosis
Authors: Seagle R. L. , Nomeir A. M. , Watts L. E.
Published: February 2009

The rare occurrence of mitral stenosis and coexistent left atrial myxoma is reported. The patient had a 25‐year history of rheumatic heart disease and was referred for evaluation of progressive mitral stenosis without clinical suspicion of left atrial myxoma. The tumor was discovered by routine echocardiography in the course of evaluation of mitral stenosis. However, prior to surgery the patient experienced an episode of embolization of the tumor without major clinical sequelae. The utility of echocardiography in this case and in patients with mitral stenosis is discussed as well as the patient' spontaneous “cure.”
Hemodynamic and clinical findings after combined therapy with metoprolol and nifedipine in acute myocardial infarction
Authors: Emanuelsson H. , Herlitz J. , Hjalmarson Å. , Holmberg S. , Waagstein F. , Waldenströ A. , Waldenströ J.
Published: February 2009

In a double‐blind trial, 30 patients with suspected acute myocardial infarction with onset of symptoms within the previous 24 h were randomized to treatment with 10 mg nifedipine/placebo orally 4 times a day during hospitalization. All patients were given 15 mg metoprolol intravenously 20 min after the initial administration of nifedipine/placebo, and thereafter, 50 mg 4 times a day. The combined therapy resulted only in moderate changes in systolic blood pressure and heart rate compared with metoprolol alone. Three of the 15 patients in the nifedipine group versus 2 of the 15 in the placebo group were withdrawn because of hypotension and/or bradycardia. None was withdrawn because of congestive heart failure or A‐V block. It is concluded that the combination of nifedipine and metoprolol seems to be a relatively well‐tolerated combination in acute myocardial infarction.
Time lapse from estimated onset of acute myocardial infarction to peak serum enzyme activity
Authors: Herlitz J. , Hjalmarson Å. , Waldenströ J.
Published: February 2009

In 581 patients with acute myocardial infarction (MI), the time lapse from estimated onset of infarction to estimated peak serum (S) enzyme activity was evaluated. Heat‐stable lactate dehydrogenase (LD; E.C. 1.1.1.27) was analyzed every 12 h for 48–108 h after arrival in hospital (n =581) and creatine kinase (CK; E.C. 2.7.3.2.; n=224), and creatine kinase subunit B (CK‐B; n=211) were analyzed every 6 h for 48 h. Peak S‐LD was observed between 14 and 110 h after estimated onset of MI (mean 46.6±0.6 h), peak S‐CK was observed between 8 and 58 h (mean 25.0±0.6 h), and peak S‐CK‐B was also observed between 8 and 58 h (mean 22.8 ±0.7 h) after onset. In 86% of patients, peak LD was reached within 60 h after onset of MI, in 78%, peak CK was reached within 30 h, and in 82%, peak CK‐B was observed within 30 h after onset of MI. A weak correlation was found between duration of pain and time lapse to S peak enzyme activity (r=0.25–0.27; p<0.001), while there was no correlation between S peak activity and time lapse from onset of MI to S peak activity. It is concluded, that although in the majority of patients with MI, peak serum‐enzyme activity is reached within a predictable amount of time after estimated onset of MI there is wide variation, difficult to establish from the clinical course, among individual patients.
Circulatory effects of mental stress during exercise in coronary artery disease patients
Authors: Siconolfi S. F. , Garber C. E. , Baptist G. D. , Cooper F. S. , Carleton R. A.
Published: February 2009

We examined the effects of mental stress during steady‐state exercise on heart rate, blood pressure, pressure‐rate product, and oxygen uptake in 10 coronary artery disease patients. Subjects walked at three mph with grade increases of 4% every two minutes until the target heart rate (60% peak heart rate from a previous symptom‐limited exercise test) was reached. A computerized Stroop‐Color‐Word Test (mental stress) was added one minute after the subject reached steady‐state exercise and lasted 11±4 minutes. When mental stress was added to steady‐state exercise it significantly (p<0.01) increased the heart rate (101 ±15 to 108± 19 beats per min), systolic (154±26 to 170 ±26 mmHg) and diastolic (86 ±10 to 92 ±13 mmHg) blood pressure, and pressure‐rate product (158 ±42 to 179±48 × 10‐‐2). This increase in the mean response during exercise and mental stress was not observed for oxygen uptake (17±6 to 18±5 ml/kg/min). The circulatory changes probably reflect increased sympathetic activity with both centrally mediated cardio‐acceleratory (and probably cardiac output) and vasoconstrictor effects during the combination of mental stress and steady‐state exercise. The altered hemodynamics without concomitant changes in oxygen uptake has major implications concerning the safety of competitive exercise for people with coronary artery disease.
Tetralogy of fallot in the elderly
Authors: Chin J. , Bashour T. , Kabbani S.
Published: February 2009

Tetralogy of Fallot was first diagnosed during life in this patient at the age of 61 years. He represents one of the oldest reported patients with this congenital heart anomaly. This report presents a case of a previously undiagnosed patient with tetralogy of Fallot.
Evaluation and treatment of fetal arrhythmias
Authors: Allan L. D. , Crawford D. C. , Tynan M. , Anderson R. H.
Published: February 2009

In a series of 31 cases referred for the evaluation of fetal arrhythmia, it was possible to identify the rhythm disturbance correctly using M‐mode echocardiography. Cross‐sectional echocardiography delineated structural abnormality where it occurred in association with an arrhythmia. Fifteen cases had premature atrial or ventricular contractions occurring in structurally normal hearts. These were not associated with perinatal mortality or morbidity in our series. Nine cases had complete heart block, three of which had structural cardiac anomalies. Seven cases were of atrial tachycardia, six were treated prenatally, one was delivered prematurely. Correct identification of an arrhythmia and appropriate prenatal therapy where indicated, was found to prevent unnecessary operative or premature deliveries.
Verapamil in chronic atrial fibrillation: Variable patterns of response in ventricular rate
Authors: Klein G. J. , Twum‐Barima Y. , Gulamhusein S. , Carruthers S. G. , Donner A. P.
Published: February 2009

We determined the effects of single intravenous (10 mg) and oral (80, 160 mg) doses of verapamil in 8 digitalized patients with chronic atrial fibrillation. The time course of drug effect was analyzed with computer assistance by considering several measures in atrial fibrillation, including average R‐R interval (ARR), shortest R‐R interval (SRR), longest R‐R interval (LRR), and variability of R‐R intervals. Peak plasma concentrations of verapamil were observed immediately after intravenous verapamil (mean elimination half‐life of 3.3 h) and 1 hour after oral verapamil (mean elimination half‐life 3.4 h, 80 mg; 3.1 h, 160 mg). In contrast to previous studies, we observed the maximum bradycardie effect of intravenous verapamil to occur at one‐half to 1 h, and this effect lasted for 2–4 h. Following oral verapamil the peak effect occurred at 3–4 h and lasted for 5–8 h. Analysise time course of changes in ARR, SRR, LRR, and variability of R‐R revealed two distinct “patterns” of ventricular response. In one group (4 of 8 patients), verapamil caused an increase in SRR but a decrease in LRR. R‐R intervals “regularized” in this group. In the remaining patients, verapamil increased the SRR but did not change or increase the LRR. This enhanced the observed increase in ARR intervals. We postulate that the decrease in LRR intervals after verapamil is due to reflex adrenergic discharge as a result of the vasodilator effect of the drug while the increase in SRR is a direct effect. These two opposing effects result in regularization of R‐R intervals in many patients. Patients demonstrating an increase in LRR intervals after verapamil may not get reflex adrenergic discharge or may be incapable of responding to the latter due to conduction disease; these patients may experience brady cardie complications after verapamil.
The use of encainide in atrial fibrillation
Authors: Vlay S. C. , Reid P. R.
Published: February 2009

Based on its electrophysiologic characteristics, encainide, a new type 1 antiarrhythmic agent, was selected for a therapeutic trial in a case of refractory paroxysmal atrial fibrillation. This approach represents an attempt to manage the pathophysiologic disturbance of atrial fibrillation by selection of a drug that would be expected to have specific effects on the conduction system.
Cardiac rhythm disorders complicating coronary arterial spasm
Authors: Bashour T.
Published: February 2009

Practically every known form of arrhythmia may complicate vasospastic ischemia. Of special importance are sinus node arrest and ventricular fibrillation. The high incidence of arrhythmia in this syndrome may be related to the usually severe profound ischemia or to the sudden massive reperfusion; both can frequently characterize transient severe segmental spasm of an artery without pre‐existing stenosis. Nitrates and calcium channel blockers may be effective in the control of vasospasm‐induced arrhythmia, but other traditional antiarrhythmic agents and pacemaker treatment may be required in some patients.
Sudden cardiac death recorded during ambulatory electrocardiographic monitoring
Authors: Hohnloser S. , Weiss M. , Zeiher A. , Wollschläger H. , Hust M. H. , Just H.
Published: February 2009

Two case reports of sudden cardiac death are detailed here. Holter monitoring plays an important role in documenting arrhythmias leading to sudden cardiac death. In addition, the importance of the Lown grading concept should not be underestimated. Our two case reports and a subsequent review of the literature demonstrate both points.

A total of 57 patients with sudden cardiac death during Hotter monitoring have been reported. In this population bradyarrhythmias can be found in about 15%. Such arrhythmias can mainly be seen in elderly patients and are predictors of a very poor outcome for these individuals.

Ventricular tachyarrhythmias in Holter recordings are the most common documented rhythm disturbances leading to sudden cardiac death. In patients with manifest cardiac diseases they are nearly always preceded by ventricular arrhythmias of the Lown grade III‐V which usually occur 3–5 h prior to the terminal event. Short coupled ventricular premature beats, so called R on T extrasystoles, were observed in more than one‐third of Holter recordings of patients suffering sudden death due to ventricular tachyarrhythmias; the importance of this phenomenon becomes obvious with this high incidence. The clinical value of these warning arrhythmias is, of course, limited because the arrhythmias were detected only after the fatal event by re‐evaluation of the Holter monitoring recordings. Nevertheless, these high‐grade ventricular arrhythmias demonstrate a marked degree of electrical instability within the heart. Furthermore, the high incidence of serious rhythm disturbances in the setting of sudden cardiac death underlines the importance of the Lown grading concept of ventricular arrhythmias (Lown and Wolf, 1971).

Polymorphous ventricular tachycardia, commonly called torsade de pointes, must be considered as the cause of sudden cardiac death in approximately 20–25% of patients. This special kind of ventricular arrhythmia may play a dominant role in the origin of sudden death in patients treated with antiarrhythmic agents. (Deneset al, 1981; Hustet al, 1983; Kerenet al., 1981). Clinical recognition is of enormous importance because therapy of torsade de pointes differs from therapy of other forms of ventricular tachyarrhthmias.
Dihydroquinidine versus disopyramide: Efficacy in patients with chronic stable ventricular ectopy
Authors: Chimienti M. , Panciroli C. , Salerno J. A. , Previtali M. , Bobba P. , Regazzi‐Bonora M. , Cristiani D. , Rondanelli R.
Published: February 2009

Dihydroquinidine (DQ) is contained in substantial amounts in quinidine salts, but its direct antiar‐rhythmic action has not been studied. The efficacy of oral DQ (300 mg t.i.d.) compared to disopyramide (D) (200 mg t.i.d.) was thus investigated using a double‐blind crossover placebo‐controlled protocol in 12 patients, aged 13 to 67 years, with chronic stable high frequency premature ventricular beats (PVB), defined as > 100 PVB/h during 48‐72‐h control Holter monitoring. The protocol included three 72‐h treatment periods: DQ, D, and placebo at random. On days 2 and 3 of each period a 24‐h Holter recording was carried out; drug blood levels were determined at peak (days 2 and 3) and trough time (day 3). No significant difference in the mean PVB/h was found between control (735±400) and placebo periods (564 ±388), or between the two Holter recordings of each period. Compared to placebo both DQ (106±113, p<0.005) and D (240±263, p<0.05) reduced the mean PVB/h, but the decrease was significantly higher with DQ (78 versus 53%, p<0.02). Nine patients (75%) on DQ and 5 (42%) on D had a >70% decrease in mean PVB/h; complex PVBs were abolished in 3 of 6 patients on both treatments. On day 3, DQ plasma levels were 1.31 ±0.44 (peak) and 0.92 ±0.45 (trough) mg/1; D plasma levels were 2.88±0.64 (peak) and 2.02±0.31 (trough) mg/1; no significant difference was found between day 2 and day 3 samples. Side effects were cutaneous rashes in one patient on DQ and pyrosis in one patient on D. The conclusion is that DQ at the doses used is a very effective and well‐tolerated antiarrhythmic agent. In this study it appeared to be superior to average doses of D for suppressing chronic ventricular arrhythmias.