bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcitonin Gene-Related Peptide Immunoreactive Cells and Fibers in Forebrain Vocal and Auditory Nuclei of the Budgerigar (Melopsittacus undulatus)
Authors: Durand Sarah E. , Brauth Steven E. , Liang Wenru
Published: April 2003

The distributions of calcitonin gene-related peptide (CGRP) immunoreactive neurons and fibers were mapped within forebrain vocal control and auditory nuclei of a vocal learning psittacine species, the budgerigar (Melopsittacus undulatus). Immunoreactivity was exhibited by telencephalic nuclei previously associated with vocal control pathways on the basis of both tract tracing studies and gene mapping: the central nucleus of the anterior archistriatum (AAc), central nucleus of the lateral neostriatum (NLc), magnocellular nucleus the lobus parolfactorius (LPOm), the oval nucleus of the ventral hyperstiratum (HVo) and the medial division of the oval nucleus of the anterior neostriatum (NAom). The main body of NAo also contained an exceptionally high density of immunoreactive fibers. In contrast to the condition in oscine songbirds, CGRP-positive neuronal somata were not present in any telencephalic vocal control nucleus. CGRP-positive somata were present, however, in diencephalic cell groups that included the shell region of the nucleus ovoidalis (Ov), the nucleus dorsolateralis posterior (DLP) and a region of the ventral thalamus that was retrogradely labeled by tracer deposits into HVo and AAc. CGRP immunoreactive fibers were observed within auditory areas of the telencephalon including Field L and the neostriatum intermedium pars dorsolateralis. The likely sources of these fibers are CGRP-positive neurons within the Ov shell and DLP.
The Oscine Song System Considered in the Context of the Avian Brain: Lessons Learned from Comparative Neurobiology
Authors: Farries Michael A.
Published: April 2003

The oscine song system has emerged as one of the leading model systems for studying motor learning in vertebrates, combining an easily recorded behavior with a discrete neural substrate. That neural substrate seems to be distinct from other structures in the avian brain and thus is often studied in isolation. However, the song system is unlikely to have evolved ex nihilo, and should share some features with the parts of the avian brain from which it evolved. Identification of its evolutionary precursors should help us apply what we know about the song system to other vertebrate motor systems, and vice versa. Here, I review the homologies between parts of the avian and mammalian telencephala and explain where the song system nuclei reside in this context. The organization of the song system is then compared to other parts of the avian brain and the brains of nonoscine birds. Study of the nonoscine brain has revealed a ‘general motor pathway’ from caudolateral neostriatum (NCL) to intermediate archistriatum (Ai) that resembles the song system motor pathway in its anatomical organization. No part of this motor pathway projects directly to brainstem vocal or respiratory centers in nonoscines, but it does innervate a wide variety of motor and premotor neuron populations that mediate other behaviors. This general motor pathway may be accompanied by an ‘anterior forebrain pathway’ , suggesting that the song system is simply a specialization of a part of this preexisting circuit. This hypothesis has implications for how accessory structures of the song system (e.g. HVc shelf, LMAN shell) are regarded, can help explain how the forebrain vocal control systems of three avian taxa (parrots, hummingbirds, and songbirds) could have evolved independently yet be so similar in organization, and makes testable predictions concerning the anatomy of the song system and the nonoscine brain.
Anti-Anginal and Anti-Ischemic Effects of Mibefradil, a New T-Type Calcium Channel Antagonist
Authors: Kobrin Isaac , Bieska Gabriele , Charlon Vincent , Lindberg Elisabet , Pordy Robert
Published: April 2003

Mibefradil is the first of a new class of calcium antagonists (CAs), the tetralol derivatives, that selectively blocks the T-type calcium channel. The anti-anginal and anti-ischemic efficacy of mibefradil in patients with chronic stable angina pectoris was established in five placebo-controlled trials (2 monotherapy trials, 3 trials with background β-blocker or long-acting nitrate therapy). At the recommended doses of 50 and 100 mg, mibefradil treatment was associated with a significant dose-related increase in exercise test variables regardless of demographic subpopulation or background therapy. Significant reductions in weekly anginal attacks, silent ischemic parameters, heart rate (HR) and rate-pressure product were also observed. Two active-controlled trials compared mibefradil 100 mg with amlodipine 10 mg or diltiazem SR 120 mg b.i.d., respectively. Patients receiving mibefradil showed significantly larger improvements than did those treated with amlodipine and similar improvements as those treated with diltiazem SR in all variables measured. In both studies, treatment with mibefradil was associated with a greater decrease in HR and rate-pressure product. Mibefradil was found to be well tolerated and safe; this held true for patients on chronic anti-anginal background therapy. The overall incidences of adverse events and premature withdrawals were only slightly higher than those of placebo-treated patients. Asymptomatic sinus bradycardia and first-degree atrioventricular block were the most frequently occurring mibefradil dose-related ECG changes. Mibefradil was better tolerated than amlodipine (mainly with regard to leg edema) and similarly well tolerated as diltiazem CD.
Different Effects of Calcium Antagonists in a Rat Model of Heart Failure
Authors: Mulder Paul , Richard Vincent , Thuillez Christian
Published: April 2003

Calcium antagonists have, to date, shown disappointing effect in chronic heart failure (CHF), possibly due to their cardiodepressant effects and/or reflex increases in sympathetic tone. Mibefradil is a new, selective T-channel calcium antagonist which has no relevant effects on cardiac contractility, sympathetic activity or neurohormonal levels. This study compares the effect of mibefradil with an angiotensin-converting enzyme (ACE) inhibitor on systemic and cardiac hemodynamics, cardiac structure and survival in a rat model of CHF. Rats underwent coronary artery ligation followed by 9 months treatment with mibefradil, cilazapril or no treatment. Both mibefradil and cilazapril increased survival rate to a similar extent over the study treatment period. Both periods reduced systolic blood pressure compared with untreated rats, although the reduction was slightly more marked with cilazapril than mibefradil. Both treatments decreased left ventricular (LV) end-diastolic and central venous pressures without any change in the first derivative LV pressure over time or heart rate. Mibefradil decreased LV weight without effecting right ventricular (RV) weight. Both drugs normalized LV collagen density. The data from this study show that long-term treatment with mibefradil results in a survival benefit comparable to that observed with an ACE inhibitor in a rat model of CHF. Mibefradil was also associated with improvements in cardiac hemodynamics, a reduction in LV weight and fibrosis. Mibefradil may be beneficial in the treatment of CHF.
Angiotensin II Antagonism and the Heart: Valsartan in Left Ventricular Hypertrophy
Authors: Thürmann Petra A.
Published: April 2003

Left ventricular hypertrophy (LVH) represents an independent risk factor for cardiovascular morbidity and mortality, and normalization of left ventricular mass has become a desirable goal of antihypertensive treatment. In a randomized, double-blind study the angiotensin II (AT1 receptor) antagonist valsartan (Diovan®; 80 mg/160 mg q.d.) was compared with the beta-blocker atenolol (50 mg/100 mg q.d.) over 8 months in predominantly previously untreated patients with essential hypertension and LVH. Sixty-nine patients were randomized, of whom 58 were evaluated with echocardiographic data. After 8 months of treatment in the atenolol group [n = 8 with additional hydrochlorothiazide (HCTZ)], initial blood pressure was reduced from 160/103 to 147/92 mm Hg (p < 0.0001), and in the valsartan group (n = 9 with additional HCTZ) blood pressure decreased from 163/101 to 146/90 mm Hg (p < 0.0001). Left ventricular mass index decreased from 127 to 117 g/m2 in the atenolol group and from 127 to 106 g/m2 in the valsartan group. Long-term treatment with valsartan resulted in a significant reduction of LVH in patients with essential hypertension.
Improving Outcomes in Congestive Heart Failure: Val-HeFT
Authors: Cohn Jay N.
Published: April 2003

The aims of the treatment of heart failure are to improve the quality of life and slow the progression of cardiac disease. Improvement of quality of life is best assessed by questionnaire; progression of the disease is assessed by measuring mortality and morbidity. The agenda for the future is to establish intermediate markers for progression of cardiac disease that can be substituted for morbidity and mortality, and thus improve the efficiency and shorten the follow-up of clinical trials. At present, polypharmacy is required to achieve optimal improvements in quality and duration of life. Furthermore, some drugs may favorably affect one end point and adversely affect the other; for example, beta-blockers may exert adverse short-term effects on quality of life but may slow progression of the disease. Certain inotropic drugs may reduce symptoms but shorten life expectancy. Angiotensin-converting enzyme (ACE) inhibitors have exerted favorable effects on both quality of life and mortality, but the magnitude of these benefits has been disappointingly small. Persistent angiotensin-induced vasoconstriction and endocrine effects, despite ACE inhibition, is one possible explanation. The Valsartan in Heart Failure Trial (Val-HeFT) has been designed to test the efficacy and safety of the AT1 receptor blocker (ARB) valsartan in combination with ACE inhibitors and all other prescribed therapies in patients with heart failure. The study is powered to detect a mortality benefit and should therefore establish the role of ARBs in this patient group. When this trial and other ongoing studies are completed, we will be more able to define the role of ARBs in the treatment of heart failure.
Altered Regulation of the Myocardial Microcirculation in Young Smokers
Authors: Madsen Mette M. , Bøttcher Morten , Nielsen Torsten Toftegaard , Czernin Johannes
Published: April 2003

Smoking is known to affect microcirculatory function in a middle-aged population. However, the effects of smoking on myocardial perfusion in young smokers have not been studied. Myocardial perfusion was measured in 15 smokers (24 ± 2 years) and 15 nonsmokers (24 ± 3 years) using positron emission tomography. Myocardial perfusion was measured at rest, during cold stress and during dipyridamole. Resting myocardial blood flow was similar in the two groups. The well-described correlation between rate-pressure product and myocardial blood flow was present only in the nonsmokers (r2 = 0.61, p < 0.001). Myocardial blood flow corrected for the rate-pressure product declined during cold by 20% in the smokers [1.11 ± 0.28 vs. 0.92 ± 0.20 ml·g–1·min–1 (p = 0.012)], but remained unchanged in nonsmokers [1.11 ± 0.25 vs. 1.09 ± 0.30 ml·g–1·min–1 (p = NS)]. Dipyridamole-induced hyperemia was similar in the two groups [2.23 ± 0.78 vs. 2.42 ± 0.65 ml·g–1·min–1 (p = NS)]. In conclusion, smoking induces abnormalities in myocardial microcirculatory regulation in young otherwise healthy smokers. The coronary flow reserve, however, is not significantly altered.
False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block
Authors: Gussak Ihor , Wright R. Scott , Bjerregaard Preben , Chaitman Bernard R. , Zhou Sophia H. , Hammill Stephen C. , Kopecky Stephen L.
Published: April 2003

Right bundle-branch block (RBBB) has not traditionally been seen as an obstacle to ECG diagnosis of Q wave myocardial infarction (MI) – in clinical electrocardiography and vectorcardiography – because this conduction disturbance is not believed to cause significant alterations in the spatial orientation of initial excitation wavefronts. In the era of large-scale clinical trials, however, where serial ECG analysis is among the major diagnostic tools in MI classification, both false-positive and false-negative diagnoses of MI in the presence of RBBB have become increasingly evident. Because of the limited detectability of Q wave MI by ECG in the presence of RBBB, the electrocardiographic finding of Q wave MI should not be regarded as an independent diagnostic tool. It is best to utilize independent corroboration to establish the diagnosis of transmural infarction when RBBB is present. Further investigations are warranted to better delineate sensitivity, specificity, and predictive value of Q wave MI in the presence of RBBB.
Is the Tissue Affinity of ACE Inhibitors of Relevance for the Remodeling of the Left Ventricular Wall following Myocardial Infarction?
Authors: Konermann M. , Sanner B.M. , Altmann C. , Laschewski F. , Rawert B. , Trappe H.J.
Published: April 2003

Background: Angiotensin-converting enzyme (ACE) inhibitors have been shown to be of value in the treatment of postinfarction remodeling. The question whether substances with a greater tissue affinity are associated with advantages for the acute and the chronic course is, however, still unclear. Aim: The aim of the present study was to investigate the influence of ACE inhibitors with differing tissue affinities on the remodeling of the left ventricular wall in patients recovering from myocardial infarction. Methods: 52 patients (17 women, aged 38–73 years) suffering their first acute myocardial infarction were randomized to receive a daily dose of either 25–75 mg captopril or 10–20 mg fosinopril, beginning on the 7th postinfarction day. 28 patients had an anterior wall infarction and 24 patients an inferior wall infarction. The size of the infarct was determined using the creatine kinase integral method. 50 patients were investigated by cine magnetic resonance imaging 1 and 26 weeks after the infarction. The following parameters were determined: infarct weight and diastolic diameter of the infarcted zone, systolic wall stress, muscle mass, diastolic and systolic diameters, systolic wall thickening, and motility of the noninfarcted myocardium. Results: The infarct weight increased under captopril by 5.7% (p < 0.05) and under fosinopril by 6.1% (p < 0.05). The diastolic diameter of the infarcted zone decreased by 12% under captopril (p < 0.001) and by 11% under fosinopril (p < 0.001). The systolic wall thickness increased by 12.1% (p < 0.001) and the muscle mass by 12.7% (p < 0.001) under captopril and by 15.4% (p < 0.001) and 9.6% (p < 0.01), respectively, under fosinopril. Under captopril, the diastolic diameter increased by 2.3% (p < 0.05) and the systolic diameter by 17.8% (p < 0.01) and under fosinopril by 2.8% (n.s.) and 17.5% (p < 0.001), respectively. The systolic wall thickening increased by 73.9% under captopril (p < 0.001) and by 129.4% under fosinopril (p < 0.001). The motility decreased by 13.8% (p < 0.05) under captopril and by 6.0% (n.s.) under fosinopril. For all parameters, the results seen in anterior wall infarction were appreciably poorer than those seen in inferior wall infarction. All the differences between captopril and fosinopril were not significant. Conclusions: Captopril and fosinopril show no major differences in their influence on left ventricular wall remodeling following myocardial infarction. On the basis of the present results, the tissue affinity of an ACE inhibitor does not appear to be of a significant relevance for postinfarction treatment.
Ventricular Fibrillation Refractory to Automatic Internal Cardiac Defibrillator in Fabry’s Disease
Authors: Eckart Robert E. , Kinney Kurt G. , Belnap Christina M. , Le Tho D.
Published: April 2003

Fabry’s disease is a disorder of glycosphingolipid metabolism leading to α-galactosidase deficiency with systemic sequelae. Clinical cardiac manifestations include dysrhythmias, structural abnormalities apparent on echocardiography, and histologic changes secondary to glycosphingolipid deposition. The introduction of automated internal cardiac defibrillators (AICD) has been shown to decrease the incidence of circulatory collapse in individuals with known terminal arrhythmias. We present a patient with Fabry’s disease, who underwent coronary angiography without finding of obstructive disease. He returned after aborted sudden cardiac death necessitating the placement of an AICD. He again presented after an episode of ventricular fibrillation refractory to internal defibrillation necessitating advanced life support, and subsequently expired. We review the electrocardiographic, cardiovascular structural, and histologic manifestations of Fabry’s disease.
Reduced Concentrations of Soluble Adhesion Molecules after Antioxidant Supplementation in Postmenopausal Women with High Cardiovascular Risk Profiles – A Randomized Double-Blind Study
Authors: Goudev A. , Kyurkchiev S. , Gergova V. , Karshelova E. , Georgiev D. , Atar D. , Kehayov I. , Nachev Ch.
Published: April 2003

Background: One of the suggested mechanisms of increased cardiovascular risk in postmenopause is a loss of the antioxidant effects of estrogens. It has been shown that classical cardiovascular risk factors increase oxidative stress on the arterial wall, and that endothelial cells react to this insult by increased expression of cellular adhesion molecules (CAM), which in turn are markers of arterial wall inflammation. Methods: A randomized, placebo-controlled, double-blind study was performed in 60 postmenopausal women with high cardiovascular risk profiles, but free from clinical atherosclerotic disease. Patients were randomized to either antioxidant supplementation (using a combination of natural antioxidants; n = 30) or placebo (n = 30), and followed for 12 weeks. The concentrations of the adhesion molecules sVCAM-1 and sICAM-1 were measured by ELISA at baseline and at the end of the study, as well as total cholesterol, LDL, HDL, triglycerides and blood pressure. Results: 27 women in the antioxidant supplementation group and 29 on placebo completed the study. At baseline, there were no significant differences in measured parameters between the groups: sICAM-1 concentrations were 341.8 ± 116.9 vs. 349.9 ± 104.6 ng/ml (active treatment vs. placebo; p = n.s.) and sVCAM-1 concentrations were 780.5 ± 325.8 vs. 761.0 ± 333.7 ng/ml (p = n.s.). In contrast, at the end of the study, sICAM-1 concentrations were 301.6 ± 56.0 vs. 356.0 ± 134.8 ng/ml (active treatment vs. placebo; p = 0.053) and sVCAM-1 concentrations were 656.0 ± 326.5 vs. 818.5 ± 381.0 ng/ml (p = 0.04). There were no significant differences between or changes within the groups in measured cholesterol and blood pressure. Conclusion: Antioxidant supplementation reduces serum concentrations of endothelium-derived adhesion molecules sICAM-1and sVCAM-1 in postmenopausal women with high cardiovascular risk profiles.
The Expression of the CD18 Leucocyte Integrin in a Rabbit Model of Acute Myocardial Infarction: A Pilot Study of Temporal Changes and Relationship to Infarct Size
Authors: Hillis Graham , Taggart Pamela , Dalsey William , Mangione Antoinette , Ma Xin-Liang
Published: April 2003

CD18 integrins mediate leucocyte adhesion to vascular endothelium. This represents the initial step in inflammatory cell infiltration following myocardial necrosis. The current studyassessed whether the expression of these rapidly activated and readily measured adhesion receptors on circulating neutrophils would reflect the extent of cardiac damage in a rabbit model of acute myocardial infarction. Myocardial ischaemia/infarction was induced in anaesthetised adult male New Zealand white rabbits (n = 8) by ligation of the circumflex or marginal coronary artery. To control for the effects of anaesthesia and surgery, 4 rabbits underwent identical procedures without the induction of infarction. Absolute infarct size (in mg) and infarct size as a percentage of total left ventricular mass (relative infarct size) were calculated by differential staining and weighing of necrotic myocardium. Flow cytometry was used to determine cell surface expression of CD18 at six time points (baseline, 20 and 45 min of ischaemia and 20, 60 and 180 min of reperfusion). Absolute neutrophil CD18 expression and changes in expression over baseline were correlated with absolute and relative infarct size. Mean neutrophil CD18 expression increased significantly (from 2.42 ± 0.20 to 3.07 ± 0.29; p = 0.04) within 20 min of ischaemia. CD18 expression at 3 h did not predict absolute or relative infarct size (r = 0.40 and 0.37, respectively). The percentage change in cell surface CD18 expression (above baseline levels) was, however, correlated with both measures of infarct size (r = 0.76, p = 0.03, and r = 0.92, p = 0.001, respectively). In conclusion, in this rabbit model of myocardial infarction, neutrophil CD18 expression rises within 20 min of the induction of ischaemia but absolute values after 3 h of reperfusion are poor indicators of infarct size. Although percentage change in neutrophil CD18 levels over baseline correlates with infarct size there is considerable variation between individuals, limiting any clinical application.
Role of Intraventricular Dispersion of Early Diastolic Filling in Indicating Left Ventricular Diastolic Dysfunction: Assessment by Color M-Mode Inflow Propagation Velocity
Authors: Voon Wen-Chol , Huang Chih-Hsin , Sheu Sheng-Hsiung
Published: April 2003

The intraventricular to mitral E velocity ratio (IvE/MvE) and the color M-mode Doppler inflow propagation velocity (LVIPV) were evaluated in 36 healthy controls and 33 patients with hypertension and/or ischemic heart disease. The intraventricular E velocity was significantly lower than the mitral E velocity in the control group (52 vs. 68 cm/s, p < 0.001), but they are similar in the disease group (59 vs. 63 cm/s, p = nonsignificant). Compared with the control group, the disease group had a higher IvE/MvE (0.95 ± 0.28 vs. 0.78 ± 0.23, p < 0.01). Nevertheless, the LVIPV was not significantly different between the disease and control groups (53 ± 14 vs. 56 ± 13 cm/s, p = nonsignificant). The LVIPV did not correlate with the IvE/MvE (r = 0.202, p = nonsignificant). Therefore, an intraventricular dispersion of early diastolic filling does not seem to indicate impaired left ventricular relaxation.
Pulsation, Systolic Thrill and Murmur in Femoral Veins Secondary to Severe Tricuspid Regurgitation
Authors: Hung Ming-Yow , Hung Ming-Jui , Kuo Li-Tang , Wang Chao-Hung , Cherng Wen-Jin
Published: April 2003

We report on a case of pulsatile femoral veins with a systolic thrill and murmur in a 26-year-old patient who exhibited severe tricuspid regurgitation. The pulsatile nature of the veins may result from the ‘ventricularization’ of venous pressure with each pressure pulse. The observed systolic thrill and murmur may be due to the systolic reversal of substantial regurgitant flow in the venous system of the lower limbs. This case also demonstrates that severe tricuspid regurgitation can have far-reaching manifestations.
Mechanical Trauma as the Major Cause of Troponin T Release after Transvenous Implantation of Cardioverter/Defibrillators
Authors: Dworschak Martin , Franz Max , Khazen Cesar , Czerny Martin , Haisjackl Markus , Hiesmayr Michael
Published: April 2003

To study the cause of myocardial injury after elective transvenous insertion of a cardioverter/defibrillator, we measured troponin T (TnT) release in 27 patients. Five patients needing only replacement of the generator with threshold testing served as controls. Compared to the control group, a significant increase in TnT occurred in the patients undergoing insertion, which was greatest in the group receiving screw-in electrodes. There was no correlation between TnT and the number and energy of the shocks and the time in fibrillation. Duration of surgery and TnT release were positively associated. Cardiac injury therefore mainly results from mechanical trauma during insertion of the electrodes and only to a lesser degree from electrical and ischemic lesions.
Prediction of Reversible Myocardial Dysfunction by Positron Emission Tomography, Low-Dose Dobutamine Echocardiography, Resting ECG, and Exercise Testing
Authors: Wiggers Henrik , Egeblad Henrik , Nielsen Torsten Toftegaard , Bøtker Hans Erik
Published: April 2003

We studied different algorithms to identify patients with heart failure who could potentially benefit from revascularization. Thirty-five coronary artery bypass (graft) patients with an ejection fraction of 35 ± 7% underwent preoperative 18F-fluoro-2-deoxyglucose positron emission tomography (PET), low-dose dobutamine echocardiography (LDDE), and exercise testing. Follow-up by echocardiography and coronary angiography was performed 6 months after coronary artery bypass grafting. The sensitivity for prediction of reversible myocardial dysfunction was highest for PET and for ST depression or angina pectoris during exercise testing (100 and 93%, p = NS), 71% for LDDE (p < 0.05 vs. PET), and 50% for resting ECG (p < 0.02 vs. PET and exercise test). The specificity did not differ between LDDE (81%), PET (67%), and resting ECG (71%), but was lowest for exercise testing (33%; p < 0.02 vs. PET, LDDE, and resting ECG). Accuracies were: PET 80%, LDDE 77%, exercise testing 62%, and resting ECG 58% (p < 0.05 vs. PET). In patients with a negative exercise test, recovery was unlikely, and further viability testing may not be needed. In patients with a positive test, recovery may occur, and additional PET or LDDE should be performed. In these cases, PET with an 18F-fluoro-deoxyglucose uptake of ≧70% as the criterion for viability yields optimum diagnostic characteristics. This strategy awaits further evaluation in larger patient populations with heart failure.
Pathophysiology of Sodium and Water Retention in Heart Failure
Authors: Cadnapaphornchai Melissa A. , Gurevich Andrei K. , Weinberger Howard D. , Schrier Robert W.
Published: April 2003

Heart failure is a leading cause of morbidity and mortality. In the United States, there are more than 5 million patients with heart failure and over 500,000 newly diagnosed cases each year. Numerous advances have been made in our understanding of the pathophysiologic mechanisms contributing to sodium and water retention in this condition. Important alterations in the sympathetic nervous system and the renin-angiotensin-aldosterone system have been described in heart failure, allowing the use of mechanism-specific treatments such as beta-adrenergic receptor antagonism and angiotensin-converting enzyme inhibition. As our understanding of the roles of the natriuretic peptides and the arginine vasopressin-aquaporin-2 system in the pathophysiology of heart failure evolves, treatments directed toward the alterations in these systems in heart failure can be further developed.
Intensive Care Unit Management of the Critically Ill Patient with Fluid Overload after Open Heart Surgery
Authors: Bellomo Rinaldo , Raman Jai , Ronco Claudio
Published: April 2003

Fluid overload is common before, during and after cardiac surgery. The fluid associated with cardiopulmonary bypass (CPB) and cardioplegia is a particularly important source of such fluid overload. In addition, renal dysfunction, which is common in these patients, participates in the pathogenesis of a positive sodium and water balance. Such fluid overload is physiologically undesirable and participates in the pathogenesis of several clinically important complications. Fluid overload can be partly prevented with the use of diuretics. However, in many patients, diuretics do not achieve sufficient sodium and water diuresis. In these patients, the application of hemofiltration (HF) during CPB and also immediately after CPB is an effective and safe approach to the maintenance of fluid homeostasis. If acute renal failure occurs, early intervention with HF may even improve survival.
Tooth–Surface Progression and Reversal Changes in Fluoridated and No–Longer– Fluoridated Communities over a 3–Year Period
Authors: Maupomé Gerardo , Shulman Jay D. , Clark D. Christopher , Levy Steven M. , Berkowitz Jonathan
Published: April 2003

Objective: To compare permanent tooth surface–specific progression/reversal changes between fluoridation–ended (F–E) and still–fluoridated (S–F) communities in British Columbia, Canada, over a 3–year period. Methods: D1D2MFS examinations were contrasted for 2,964 schoolchildren in 1993/94 (grades 2, 3, 8 and 9) and 1996/97 (grades 5, 6, 11 and 12). Generalized Estimating Equation (GEE) models explored the relation between progression/reversal changes and fluoridation status, age, gender, socioeconomic status, and dietary/fluoride histories. Results: Within a scenario of low levels of caries overall, few children had multiple surfaces progressing. At least one smooth surface progressed in 31.4% of subjects; at least one pit–and–fissure (PF) surface progressed in 43.1% of subjects. At least one smooth surface reverted in 89% of subjects who had reversible stages; at least one PF surface reverted in 23.8% of subjects who had reversible stages. GEE (smooth) indicated that odds ratios of progression were twice as large in the F–E site compared to the S–F site, and slightly increased in older participants and in participants exposed to more fluoride technologies. GEE (PF) also indicated that progression was slightly more common in the F–E site; more frequent snacking and lower parental educational attainment had modest associations with increased progression in PF surfaces. For the two types of surfaces, GEE models demonstrated that unerupted surfaces were less likely to progress than sound surfaces. No associations were found between reversals and independent variables. Conclusion: Progressions were found to be weakly linked to socio–demographic factors; baseline surface statuses were better predictors of progression. Using the current definitions for disease transitions, F–E communities had more frequent progressions than a S–F community.
Effect of Dentifrice Containing Fluoride and/or Baking Soda on Enamel Demineralization/ Remineralization: An in situ Study
Authors: Cury J.A. , Hashizume L.N. , Del Bel Cury A.A. , Tabchoury C.P.M.
Published: April 2003

The additive effect of baking soda on the anticariogenic effect of fluoride dentifrice is not well established. To evaluate it, a crossover in situ study was done in three phases of 28 days. Volunteers, using acrylic palatal appliances containing four human enamel blocks, two sound (to evaluate demineralization) and two with artificial caries lesions (to evaluate remineralization), took part in this study. During each phase, 10% sucrose solution was dripped (3 times a day) only onto the sound blocks. After 10 min, a slurry of placebo, fluoride (F) or fluoride and baking soda (F+NaHCO3) dentifrice was dripped onto all enamel blocks. The results showed a higher F concentration in dental plaque formed during treatment with F+NaHCO3 than placebo (p<0.05), but the difference related to F dentifrice was not significant. The enamel demineralization was lower, and remineralization was greater, after treatment with F+NaHCO3 than placebo (p<0.05), but the difference related to F dentifrice was not significant. The data suggest that baking soda neither improves nor impairs the effect of F dentifrice on reduction of demineralization and enhancement of remineralization of enamel.
Determination of Fluoride Intake from Urinary Fluoride Excretion Data in Children Drinking Fluoridated School Milk
Authors: Ketley C.E. , Lennon M.A.
Published: April 2003

Twenty–four–hour urine samples were collected from each of thirteen 5– to 6–year–old children both under customary conditions of fluoride intake (i.e. usual diet including milk containing 0.5 mg fluoride and usual oral hygiene procedures with fluoride toothpaste) and during a 4–day study period in which their customary fluoride intake was replaced with standard fluoride doses. The 24–hour fluoride excretion under customary conditions of fluoride intake was 0.30 mg and in response to fluoride doses in the range of 0.5–2.0 mg it was in the range 0.26–0.61 mg. Using data obtained during the study period for all subjects combined, the fluoride intake from all sources under customary conditions was estimated as 0.76 mg, representing a fractional fluoride excretion of 39%. It is concluded that these children are possibly receiving suboptimal amounts of fluoride.
Cariogenic Potential of Lactosylfructoside as Determined by Acidogenicity of Oral Streptococci in vitro and Human Dental Plaque in situ
Authors: Hata S. , Mayanagi H.
Published: April 2003

The cariogenic potential of lactosylfructoside [O–β–D–galactopyranosyl–(1→4)–O–α–D–glucopyranosyl–(1↔2)–β–D–fructofuranoside] was estimated by experiments on oral streptococci in vitro and human dental plaque in situ. Lactosylfructoside was unable to support growth of the strains of Streptococcus mutans and S. sobrinus used in this study. However, it was able to support growth of strains of S. sanguis, S. mitis and S. oralis. Acid was produced rapidly by cell suspensions of S. oralis ATCC 10557 incubated with lactosylfructoside. Application of 5% w/v solution decreased the pH of human dental plaque. The minimum pH value was below 5.3. The results suggest that lactosylfructoside is as acidogenic as lactose and could be cariogenic if it is consumed frequently and retained for a long period in the mouth.
Removal of Caries Using only Hand Instruments: A Comparison of Mechanical and Chemo–Mechanical Methods
Authors: Nadanovsky P. , Cohen Carneiro F. , Souza de Mello F.
Published: April 2003

The aim of this study was to evaluate the efficacy, comfort and efficiency of removing dentin caries using only hand instruments. The Carisolv™ system for caries removal consisting of a solvent gel and a set of specially designed hand instruments (chemo–mechanical) was compared to the use of conventional spoon excavators (mechanical). This was a clinical randomised controlled trial where the two techniques were compared in the same individual. The outcome variables were: complete caries removal; pain during caries removal; anaesthesia requested by the patient during caries removal; time taken to remove caries. Sixty–six individuals, each with a pair of similar cavities in permanent teeth were selected. After caries removal, a ‘blinded’ evaluator assessed the clinical status of the cavity, with the use of a probe. The times for caries removal of the chemo–mechanical and mechanical methods were respectively: 9.2±3.8 and 8.6±3.8 min (p>0.05). There were 4 cavities arguably presenting signs of caries after cavity preparation in the 66 cavities treated with the mechanical method and 7 in the 66 chemo–mechanical cavities (p>0,05). Some pain/discomfort was reported by 21 (32%) participants when the chemo–mechanical method was used, compared with 43 (65%) when the mechanical method was used (p<0.05). During the chemo–mechanical and the mechanical treatment, 2 (3%) and 5 (8%) patients, respectively, requested local anaesthesia (p>0.05). The chemo–mechanical method appeared to be more comfortable for most patients.
Is There a Need to Reclassify Acute Stroke Patients?
Authors: Schwartz A. , Gass A. , Hennerici M.G.
Published: April 2003

During the last decade classification of stroke patterns has been a need not only for a common scientific language but also for early clinical and therapeutic stratification. The underlying idea was to find a tool to determine the causal pathology from the stroke pattern. Confirmation of the origin of stroke as early as possible (preferably already during the first hours, <3–6 h) by definition of a pattern opened the door to a differentiated therapy by e.g. thrombolysis, anticoagulation, thrombendarterectomy and many others.
Conclusion
Authors: Orgogozo Jean-Marc
Published: April 2003

The repeated failure of almost all acute stroke trials to produce reproducible evidence of clinical benefit means that patients continue to suffer hopelessly from cerebral infarction, and the health professionals in charge of them remain in great need of therapeutic progress.
Quantitative Neuroimaging for the Evaluation of the Effect of Stroke Treatment
Authors: Heiss Wolf-Dieter , Graf Rudolf , Grond Martin , Rudolf Jobst
Published: April 2003

A prerequisite for the successful treatment of acute ischaemic stroke is the existence of viable tissue that is morphologically intact but functionally impaired due to a flow decrease below a certain threshold. At this stage, tissue at risk of infarction can be identified only by functional imaging. This penumbral tissue can be classified as having a critical flow decrease with preservation of oxygen consumption and therefore increased oxygen extraction. Such ‘misery-perfused’ tissue has been observed consistently in the first few hours following ischaemic stroke but usually develops into necrosed tissue at follow-up observations. Several studies have indicated that penumbral tissue can be identified up to 17 h or even 48 h after stroke in the border zones of ischaemic tissue and that this condition is occasionally reversible without resulting in permanent infarction. Positron emission tomography studies of cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and cerebral metabolic rate of glucose (CMRglc) can be used to demonstrate the effect of treatment on functional variables within tissue showing perfusional disturbances. Such studies have shown the value of these markers of ischaemia, which also correlate with clinical efficacy. However, when therapeutic strategies, such as thrombolysis, do not permit arterial blood sampling, quantitative determinations of CBF and CMRO2 are not feasible. In such cases relative indices, such as those for CBF, must be applied. Such qualitative assessments of perfusion, which were calibrated in an independent cohort of patients with acute stroke, were used to demonstrate the effect of early systemic treatment of acute ischaemia with recombinant tissue plasminogen activator. By applying operationally defined thresholds for tissue viability and the penumbra, and co-registering these tissue compartments to infarcted and non-infarcted tissue on late magnetic resonance imaging, the proportions of at-risk tissue salvaged from infarction could be revealed in individual patients. In the future, functional imaging modalities that could eventually include tracers for neuronal integrity could be used to select patients for thrombolytic therapy. In some instances such techniques may permit the extension of the critical time period for inclusion of patients to aggressive stroke management strategies.
Update on Clinical Trials of Antiplatelet Therapy for Cerebrovascular Diseases
Authors: Bhatt Deepak L. , Kapadia Samir R. , Yadav Jay S. , Topol Eric J.
Published: April 2003

Antiplatelet medications are an important part of the therapy of cerebrovascular diseases. Oral agents such as aspirin have an established role in the secondary prevention of stroke. An aspirin and dipyridamole combination has recently been approved. Ticlopidine has been proven to be more effective than aspirin, but its potentially serious side effect profile makes long-term use hazardous. Clopidogrel has been demonstrated to be both more effective than and at least as safe as aspirin. The combination of clopidogrel plus aspirin represents the likely future therapy for high-risk patients. The role of oral antiplatelet therapy in the acute treatment of stroke is beginning to be clarified. Aspirin treatment appears to be strongly indicated. Intravenous antiplatelet therapy with glycoprotein IIb/IIIa inhibitors for acute stroke and as an adjunct to carotid artery stenting appears promising.
Parkinsonism in Patients with Vascular Dementia: Clinical, Computed- and Positron Emission-Tomographic Findings
Authors: De Reuck J. , Siau B. , Decoo D. , Santens P. , Crevits L. , Strijckmans K. , Lemahieu I.
Published: April 2003

Purpose: The present study investigates the vascular nature of parkinsonian features in patients with ‘probable’ vascular dementia. Patients and Methods: Forty patients with vascular dementia were studied with positron emission tomography (PET) using the steady state technique with 15O in order to assess regional cerebral blood flow (rCBF), regional oxygen extraction rate (rOER) and regional metabolic rate for oxygen (rCMRO2) in different brain regions. The findings in 10 patients with (VaDP) were compared to 30 without parkinsonism (VaD). Results: The clinical and computed tomographic findings in the parkinsonian patients were similar to those described in the literature as probable vascular parkinsonism. The PET results showed decreased rCBF and rCMRO2 in the frontal and parietal cortices and in the striatum of the VaDP compared to the VaD group. The decrease of rCBF and rCMRO2 in frontal and parietal cortices is due to the more severe mental changes in the VaDP group. In the VaDP patients rCBF and rCMRO2 were more decreased and rOER increased in the striatum contralateral to the most affected parkinsonian side. Conclusion: Our PET findings show that local ischemic changes in the striatum contribute to parkinsonism in vascular dementia patients.
Parental Causes of Death in Stroke
Authors: Starr John M. , Rush Margaret , De Mey Rhona , Dennis Martin S.
Published: April 2003

There are many reports of familial aggregation in stroke. However, whether familial aggregation is largely due to genetic or environmental factors is not established. Consecutive subjects with stroke were matched with 2 controls per case of the same sex, born in the same year, district, and whose fathers had the same occupation. Presence on parental death certificates of cerebrovascular disease, other vascular disease, bronchial carcinoma, hypertension, diabetes mellitus and other causes of death was recorded. No significant difference in risk was found for cases having mother (odds ratio, OR 1.08, 95% confidence interval, CI, 0.74–1.57), father (OR 0.91, 95% CI 0.58–1.45) or either parent (OR 1.04, 95% CI 0.74–1.46) with cerebrovascular disease. Familial aggregation may reflect socioeconomic and other environmental factors.
Relevance of Experimental Ischemia in Cats for Stroke Management: A Comparative Reevaluation
Authors: Heiss Wolf-Dieter , Graf Rudolf , Wienhard Klaus
Published: April 2003

Repeat studies in animal models of acute focal ischemia can be compared to incidental studies in the course of ischemic stroke in order to shed light on the development of changes causing ischemic infarcts or recovery of critically perfused tissue. Positron emission tomography (PET) studies of regional cerebral blood flow, cerebral metabolic rate for oxygen, oxygen extraction fraction (OEF), cerebral metabolic rate of glucose and flumazenil (FMZ) binding in the cat middle cerebral artery occlusion (MCAO) model and in patients with acute ischemic hemispheric stroke were reviewed. After permanent MCAO, the development of ‘misery-perfused’ penumbral tissue and its centrifugal conversion into necrosis could be demonstrated, resembling focal pathophysiological changes in patients with ischemic attacks. In the experimental model and in vascular insults in humans, a chance of recovery existed if collateral perfusion developed spontaneously within the first hours. In transient MCAO, reperfusion was only effective in preventing infarction when it was initiated as long as misery perfusion persisted; in these cases tissue was salvaged and large infarcts did not develop. In the other instances when oxygen metabolism broke down, and an increased OEF was no longer seen, reperfusion even at levels above preocclusion had no effect, and large space-occupying infarcts developed. These experimental findings are comparable to the variable outcome after thrombolytic therapy; if reperfusion is achieved within the therapeutic window of tissue viability, large infarcts are prevented and complete or partial recovery can be achieved. In the experimental model of focal ischemia and in human stroke, FMZ can be utilized as a marker of neuronal integrity. If FMZ binding in the cortex is decreased below 4 times the mean value of white matter in the acute stage, permanent infarcts were observed on late CT/MRI; this irreversible damage could not be prevented by thrombolytic therapy. These results demonstrated that PET studies in suitable ischemia models in cats can help to explain various courses and diverging outcomes of acute ischemic stroke. Comparable findings from experimental ischemia and human stroke may affect the selection of appropriate therapeutic strategies.
Echo-Enhanced Transcranial Color-Coded Duplexsonography to Study Collateral Blood Flow in Patients with Symptomatic Obstructions of the Internal Carotid Artery and Limited Acoustic Bone Windows
Authors: Gahn Georg , Hahn Gabriele , Hallmeyer-Elgner Susanne , Kunz Alexander , Straube Torsten , Bourquain Holger , Reichmann Heinz , von Kummer Rüdiger
Published: April 2003

We prospectively evaluated 30 consecutive patients with echo-enhanced transcranial color-coded duplexsonography (TCCD) and correlative transfemoral digital subtraction angiography to assess the diagnostic efficacy of echo-enhanced TCCD for evaluation of collateral pathways through the circle of Willis in patients with limited acoustic bone windows and critical symptomatic carotid disease. Echo-enhanced TCCD detected collateral blood flow through the anterior communicating artery in 16 of 18 patients (sensitivity 89%, 95% CI 65–99%) and was false positive in one out of 12 patients without collateral flow (specificity 92%, 95% CI 59–100%). For the posterior communicating artery, sensitivity was 11/14 (79%, 95% CI 49–95%) and specificity was 15/16 (94%, 95% CI 70–100%). Echo-enhanced TCCD enables to study collateral blood flow through the communicating arteries of the circle of Willis with high sensitivity and specificity in patients with obstructions of the internal carotid artery and limited acoustic bone windows.
Amantadine Increases Gait Steadiness in Frontal Gait Disorder due to Subcortical Vascular Encephalopathy: A Double-Blind Randomized Placebo-Controlled Trial Based on Quantitative Gait Analysis
Authors: Baezner H. , Oster M. , Henning O. , Cohen S. , Hennerici M.G.
Published: April 2003

In a randomized, double-blind placebo-controlled trial, 40 patients diagnosed as subcortical vascular encephalopathy (SVE) were given a daily dose of 500 ml i.v. amantadine vs. placebo for 5 days. Both groups were treated with physiotherapy on a daily basis. Quantitative gait analyses were performed at days 1 and 6 to evaluate gait steadiness from cadence, length of heel-to-toe movements, variability of centre of gravity (COG) and double support time. Both placebo- and amantadine-receiving patient groups showed mild improvement in gait parameters after study, which failed to show the superiority of amantadine, when comparing drug-induced changes between both groups. However, analysing the treatment effects from day 0 to day 6 in both groups separately, statistically significant changes could be found in the amantadine group for cadence, length of heel-to-toe movements in single support phase as well as for variability in double support phase and double support time (two-tailed paired t-test, p < 0.05), whereas in the placebo group, a statistically significant effect could only be seen for double support time (p < 0.05). In this small pilot study, amantadine tends to improve gait steadiness as evaluated by cadence, length of heel-to-toe movements in single support phase, variability in double support phase and double support time, in patients with moderate frontal gait disorder due to SVE. Improvements in the placebo group can be interpreted as physiotherapy effect, which improved gait steadiness slightly, however, this was statistically significant only for double support time.