bluuebunny/crossref_metadata_2025 huggingface dataset:
Sudden Cardiac Death and Inherited Arrhythmia Syndromes
Authors: SARKOZY ANDREA , BRUGADA PEDRO
Published: September 2005

Sudden cardiac death (SCD) at youth is rare and is often caused by inherited cardiac disorders. This review focuses on the genetic background of inherited primary electrical diseases, the so‐called “channelopathies.” Following a short clinical description of each syndrome, the recent findings in the genetics of long QT syndrome, short QT syndrome, isolated cardiac conduction defect, familial sick sinus syndrome, familial atrial fibrillation, cathecholaminergic polymorphic ventricular tachycardia, familial Wolff‐Parkinson‐White (WPW) syndrome, and Brugada syndrome are discussed. The currently proposed theoretical model of overlapping phenotypes in SCN5A sodium channel mutations is presented. The recent data indicate that advances in molecular genetics, experimental and clinical electrophysiology shed some light on the genetic background of primary electrical diseases. However, it is also becoming clear that the process from a mutation of a gene to the clinical presentation of a patient is currently only partially understood and extremely complex.
Prevention of Sudden Cardiac Death
Authors: CANNOM DAVID S.
Published: September 2005

Although the annual incidence of sudden cardiac death (SCD) is dropping in the United States, therapies for the patient who has survived a SCD episode or is at high risk of developing SCD in the future are now well established. The implantable cardioverter defibrillator (ICD) has emerged from a series of well done randomized clinical trials of the 1990s as providing a survival benefit in carefully defined patient groups with low ejection fraction of any cause. Patients with either an ischemic or idiopathic dilated cardiomyopathy and an EF ≤35% show a significant survival benefit with the ICD and maximal medical therapy. Many challenging patients (e.g., those with long QT syndrome or Brugada syndrome) who have a reasonably high incidence of sudden death have not been the subject of clinical trials involving the ICD and therapy depends on risk stratification that is currently not completely agreed upon. An exciting research frontier of the future will be those that attempt to integrate the appropriate role of the ICD with the ability of chronic resynchronization therapy to enhance left ventricular function in the damaged ventricle.
Cardiac Resynchronization Therapy
Authors: KASS DAVID A.
Published: September 2005

Cardiac resynchronization therapy (CRT) is a recently developed approach to treat dilated heart failure with discoordinate contraction. Such dyssynchrony typically stems from electrical delay that then translates into mechanical delay between the septal and lateral walls. Over the past decade, many studies have examined the pathophysiology of cardiac dyssynchrony, tested the effects of cardiac resynchronization on heart function and energetics,tested the chronic efficacy of this therapy to enhance symptoms and reduce mortality, and better established which patients are most likely to benefit. This brief review discusses these topics.
Identifying the High Risk Patient with Coronary Artery Disease—Is Ejection Fraction All You Need?
Authors: BUXTON ALFRED E.
Published: September 2005

Although the total number of deaths resulting from cardiovascular disease has decreased in the United States, the percentage of cardiac deaths that occur suddenly has increased. Over the past 10 years, a number of randomized clinical trials have evaluated the ability of antiarrhythmic therapy to reduce mortality in patients in patients with chronic coronary disease and abnormal left ventricular function that had not yet developed spontaneous sustained VT or VF. A majority of these trials have demonstrated that the implantable cardioverter‐defibrillator (ICD) can reduce mortality compared to pharmacologic antiarrhythmic therapy, or no specific antiarrhythmic therapy. While, reduced left ventricular ejection fraction (EF) has been a major determinant for entry into these studies, in all but one case, it was not the sole entry requirement. These studies have demonstrated that a number of factors have prognostic significance, and therefore impact efficacy of the ICD. None of these studies was designed to evaluate the relative efficacy of various risk factors. Therefore, we lack adequate information today to determine the most cost‐effective manner in which to assign use of ICDs for primary prevention. This article reviews the potential for using EF alone as a risk factor, as well as the efficacy of other variables for risk stratification.
New Tools for the Effective Delivery of Cardiac Resynchronization Therapy
Authors: LEÓN ANGEL R.
Published: September 2005

Cardiac resynchronization therapy (CRT) has been shown to provide symptom relief to many patients who have congestive heart failure (CHF). Still, there are technical concerns with implanting CRT systems, and these range from inadequate venous anatomy to a variety of left ventricular (LV) lead problems. Fortunately, there are several new implant tools to help physicians achieve a stable and adequate LV pacing site. There are a number of guiding catheter shapes to tailor the choice to specific anatomic abnormalities that may be encountered during implants. Key to success was the development of over‐the‐wire LV leads that are capable of maneuvering within complex venous anatomy. Improvements in LV leads have included increasing lead diameter and bipolar design. In some cases, epicardial LV lead placement may be necessary at surgery. The latest systems have begun to integrate disease management modalities, which hopefully will reduce the need for CHF hospitalizations.
Different Clinical Features of Aortic Intramural Hematoma Versus Dissection Involving the Descending Thoracic Aorta
Authors: Falconi Mariano , Oberti Pablo , Krauss Juan , Domenech Alberto , Cesáreo Vicente , Bracco Daniel , Pizarro Rodolfo
Published: September 2005

Objective: The objective of this study is to test the hypothesis that the absence of flow communication in aortic intramural hematoma (IMH) involving the descending aorta may have a different clinical course compared with aortic dissection (AD). Methods: We prospectively evaluated clinical and echocardiographic data in AD (76 patients) and IMH (27 patients) of the descending thoracic aorta. Results: Patients did not differ with regard to age, gender, or clinical presentation. IMH and AD had the same predictors of complications at follow‐up: aortic diameter (>5 cm) at diagnosis and persistent back pain. Surgical treatment was more frequently selected in AD (39% vs. 22%, P < 0.01) and AD patients who underwent surgical treatment had higher mortality than those with IMH (36% vs. 17%, P < 0.01). There was no difference in mortality with medical treatment (14% in AD vs. 19% in IMH, P = 0.7). During follow‐up, of 23 patients with IMH, 11 (47%) showed complete resolution or regression, 6 (26%) increased the diameter of the descending aorta, and typical AD developed in 3 patients (13%). No changes occurred in 14% of the group. Three‐year survival rate did not show significant differences between both groups (82 ± 6% in IMH vs. 75 ± 7% in AD, P = 0.37). Conclusion: IMH of the descending thoracic aorta has a relatively frequent rate of complications at follow‐up, including dissection and aneurysm formation. Medical treatment with very frequent imaging and timed elective surgery in cases with complications allows a better patient management.
Idiopathic Hypereosinophilic Syndrome Associated with Multiple Intracardiac Thrombi
Authors: Kocaturk Hasan , Yilmaz Mustafa
Published: September 2005

A 17‐year‐old man was referred for dyspnea, fatigue, and fever. Idiopathic hypereosinophilic syndrome was diagnosed. Transthoracic echocardiography demonstrated multiple intracardiac thrombi in the left ventricular apex. Dissolution of thrombi was not seen despite intensive medical therapy. The patient died because of cerebral embolus.
Intracardiac Thrombosis in Multiple Chambers and Descending Aorta Manifested as Systemic and Pulmonary Thromboembolism
Authors: Hsu Chih‐Hsin , Chao Ting‐Hsing , Tsai Wei‐Chuan , Li Wei‐Ting , Liu Ping‐Yen , Lin Li‐Jen , Chen Jyh‐Hong , Tsai Liang‐Miin
Published: September 2005

We report a case with multiple thrombosis that underwent sudden circulatory collapse due to acute pulmonary embolism and ischemic stroke. Further confirmed by transesophageal echocardiography, the thrombus in both atria was detected by transthoracic echocardiography. In addition, patent foramen ovale and another thrombus in the descending aorta were readily identified by transesophageal echocardiography. Aspirin was prescribed and thrombi disappeared 1 month later. Our case report suggests that patients undergoing sudden collapse with unexplained hypoxemia and new neurological deficit secondary to coexistence of pulmonary and systemic embolism should be promptly evaluated by echocardiography, especially transesophageal one, with high suspicion for paradoxical embolism.
Three‐Dimensional Echocardiographic Assessment of a Patient Supported by Intravascular Blood Pump Impella Recover 100
Authors: Catena Emanuele , Barosi Alberto , Milazzo Filippo , Paino Roberto , Pelenghi Stefano , Garatti Andrea , Colombo Tiziano , Vitali Ettore
Published: September 2005

Impella Recover 100 is an intravascular microaxial blood pump designed for short‐term circulatory support in conditions of reduced left ventricular function. Two‐dimensional echocardiography is a consolidated tool to study and monitor patients undergoing circulatory support. Three‐dimensional (3D) echocardiography is emerging as a source of more accurate analysis in heart morphology and function. We described the use of 3D echocardiography in a patient who underwent Impella recover 100 support for postcardiotomy shock. 3D echocardiography allowed complete visualization of the pump and provided excellent intraoperative assessment of the complex spatial location into the left ventricle.
Accuracy of Tissue Doppler Echocardiography in the Emergency Diagnosis of Decompensated Heart Failure with Preserved Left Ventricular Systolic Function: Comparison with B‐Type Natriuretic Peptide Measurement
Authors: Arques Stephane , Roux Emmanuel , Sbragia Pascal , Ambrosi Pierre , Taieb Lionel , Pieri Bertrand , Gelisse Richard , Luccioni Roger
Published: September 2005

Background: Tissue Doppler echocardiography provides a reliable noninvasive estimation of left ventricular (LV) filling pressures irrespective of LV ejection fraction. However, the diagnostic accuracy of E/Ea ratio has not been adequately determined in patients with suspected heart failure (HF) with preserved LV systolic function in the acute care setting. Objective: To investigate the accuracy of E/Ea ratio in the emergency diagnosis of decompensated HF with preserved LV systolic function. Methods: Seventy patients with a LV ejection fraction ≥45%, 32 with decompensated HF (77 ± 12 years of age), and 38 with noncardiac cause of acute dyspnea (74 ± 12) were enrolled. B‐type natriuretic peptide (BNP) was measured on admission; lateral, septal and average E/Ea ratios were calculated within 24 hours. Results: Using receiver‐operating characteristic curves to evaluate diagnostic performance, BNP (AUC of 0.875, P < 0.0001) and E/Ea ratios (AUC of 0.90–0.92, P < 0.0001) provided similar accuracy for predicting decompensated HF. Optimal cutoffs were 146 pg/ml for BNP (sensitivity and specificity of 90.6% and 76.3%), 9.8 for lateral E/Ea (83.3% and 88.9%), 12.7 for septal E/Ea (76.7% and 91.4%), and 11.5 for average E/Ea ratio (80% and 94.3%). On multivariate logistic regression analysis, average E/Ea ratio yielded independent additional information to a model based on the clinical judgment and BNP level according to the standard cutoff of 100 pg/ml. Conclusions: Tissue Doppler echocardiography is accurate for predicting decompensated HF with preserved LV systolic function and may be used as a diagnostic complement to inconclusive BNP level in this setting.
Color M‐Mode Flow Propagation Velocity: Is It Really Preload Independent?
Authors: Lin Shih‐Kai , Hsiao Shih‐Hung , Lee Tao‐Yu , Huang Wei‐Chen , Hsu Tsui‐Lieh , Mar Guang‐Yuan , Liu Chun‐Peng
Published: September 2005

Objective: This study investigates the change in flow propagation velocity (FPV) in uremic patients who undergo regular hemodialysis (H/D). Materials and Methods: We studied 93 uremic patients (44 men and 49 women; 59 ± 14‐years‐old) receiving regular hemodialysis. Patients were separated by baseline left ventricular ejection fraction (LVEF): 71 patients with LVEF > 50% (group 1), 13 patients with LVEF 35–50% (group 2), 7 patients with LVEF < 35% (group 3). All patients were in sinus rhythm before H/D. They received complete transthoracic echocardiographic examinations. Flow propagation velocity was measured by color M‐mode echocardiography in apical four chambers view. All these parameters were obtained before and after H/D. Paired data were compared. According to different H/D amounts, we viewed the FPV response after H/D in variant baseline LVEF groups. Result: The baseline FPV became lower in patients with low LVEF. After H/D, obvious decrement of FPV occurred in group 1, but there were no obvious changes in groups 2 and 3. In fact, a slight increment of FPV was found in group 3. In patients with baseline LVEF > 50%, FPV after H/D was almost always lower, regardless of H/D amount. But there was different response in patients with baseline LVEF < 50%. Conclusion: Flow propagation velocity is preload independent in patients with LVEF < 50%, but it is preload‐dependent in patients with LVEF > 50%.
Left Ventricular Pseudoaneurysm Developing as a Late Complication of Coronary Artery Bypass Grafting with Apicoseptal Plication
Authors: Ozeke Ozcan , Golbasi Zehra , Cagli Kerim , Tufekcioglu Omac
Published: September 2005

Left ventricular pseudoaneurysm is a false aneurysm, which results from a left ventricle rupture contained by adherent pericardium or scar tissue. The most common etiology of left ventricular pseudoaneurysm is acute myocardial infarction but one‐third of pseudoaneurysms develop following surgery. We present a case report of a patient who developed a false aneurysm of the left ventricle 2 months following surgical repair of a left ventricular aneurysm with a concomitant coronary bypass.
Left Atrial Compression by Thoracic Aneurysm Mimicking Congestive Heart Failure
Authors: Celenk Mehmet K. , Ozeke Ozcan , Selcuk M. Timur , Selcuk Hatice , Cagli Kerim
Published: September 2005

Most patients with thoracoabdominal aortic aneurysm are asymptomatic and this aneurysm has rarely been reported as a cause of congestive heart failure. We present an infrequent case of extrinsic left atrial compression caused by a descending thoracic aneurysm diagnosed by transthoracic echocardiography as a cause of heart failure.
Systolic Wall Stress May Affect the Intramural Coronary Blood Flow Velocity in Myocardial Hypertrophy, Independently on the Left Ventricular Mass
Authors: De Gregorio Cesare , Micari Antonio , Di Bella Gianluca , Carerj Scipione , Coglitore Sebastiano
Published: September 2005

Aim: We sought to evaluate the relationship between left ventricular systolic wall stress (LV‐SWS) and coronary artery blood flow velocity in patients with LV hypertrophy (LVH). Methods and Results: The study population comprised 38 patients, aged 66.7 ± 12.7, who were divided into two groups based on the LV‐SWS median value. Group A included 19 patients at “low‐stress” (92.0 ± 18.0 mmHg/cm2) and group B other 19 patients at “high‐stress” (134.2 ± 32.3 mmHg/cm2) (P < 0.002). Coronary blood flow velocities were measured both in the left anterior descending (LAD) and in the intramural (IM) arteries. There were no significant between‐group differences in the main clinical and echocardiographic parameters. Diastolic velocity in the LAD was also comparable, while it was higher in the IM arterioles of patients from group B than from group A (peak velocity 110.9 ± 35.2 cm/s vs 92.0 ± 29.4 cm/s, P < 0.02; mean velocity 78.6 ± 28.8 vs. 56.0 ± 20.2 cm/s, P < 0.01, respectively). Overall, moderate, but significative, linear correlation was found between IM peak and mean diastolic velocity and LV‐SWS (r = 0.41, P = 0.01, and r = 0.44, P = 0.007, respectively), whereas there was no correlation with wall thickening and LV mass. Conclusions: Main findings from the present study likely suggest that in patients with mild‐to‐moderate LVH, high blood flow velocity in the IM arterioles, but not in the LAD, may be related to an increase in LV‐SWS, rather independent on the absolute LV mass.
Effects of Anesthesia on Diastolic Function in Mice Assessed by Echocardiography
Authors: Schaefer Arnd , Meyer Gerd Peter , Brand Birgit , Hilfiker‐Kleiner Denise , Drexler Helmut , Klein Gunnar
Published: September 2005

Background: Transthoracic echocardiography is the predominant diagnostic tool to evaluate systolic and diastolic cardiac function noninvasively in mice. It is known that systolic function is substantially influenced by anesthetic agents used for sedation during echocardiography. However, the effect on diastolic function has not been investigated yet. The following study was conducted to evaluate the influence of different agents on diastolic left ventricular function in mice. Methods and Results: The effect of ketamine/xylazine (K/X), ketamine/midazolam (K/M), and tribromoethanol (TBE, Avertin) on diastolic function was measured 5, 15, and 25 minutes after the onset of anesthesia. Ratio of peak early‐to‐late myocardial diastolic velocities (Ea/Aa; determined by tissue Doppler imaging; TDI), ratio of peak transmitral early (E)‐ and late‐diastolic velocity (E/A), deceleration time (DT), and isovolumic relaxation time (IVRT) correlated significantly with heart rate (HR). Overall, increasing HR contributed to a decrease of E/A‐, Ea/Aa ratio, IVRT, and DT, whereas agents characterized by the strongest variation of HR (K/M and TBE) were associated with the greatest effect on diastolic function. Conclusion: Left ventricular diastolic function in mice, determined by echocardiography, is dependent on anesthetic agent and timing of measurements after onset of anesthesia.
Rare Flow Pattern in a Patient with Cor Triatriatum
Authors: Ghalchi Michael , Rosenzweig Barry P. , Colvin Stephen B. , Tunick Paul A. , Kronzon Itzhak
Published: September 2005

Doppler echocardiography demonstrated a rare flow pattern due to cor triatriatum that is also present in subvalvular or supravalvular mitral stenosis: a forward gradient, in both systole and diastole.
Microstructural Development and Creep Deformation in an Alumina–5% Yttrium Aluminum Garnet Composite
Authors: Satapathy L. N. , Chokshi A. H.
Published: September 2005

An alumina–5 vol% yttrium aluminum garnet (YAG) composite was obtained through in situ reaction of alumina and yttria during sintering. Analysis of creep experiments together with microstructural data indicated that both pure alumina and alumina–5 vol% YAG composite deform by a Coble grain boundary diffusion creep process. Comparison with other data suggests that at temperatures greater than ∼1650 K, an isolated or interconnected fine‐grained YAG phase does not significantly affect creep in alumina. However, an isolated YAG phase retards both static and dynamic grain growth in the composite.
High Critical Current YBa2Cu3O7−δ Thick Films on Improved Rolling‐Assisted Biaxially Textured Substrates (RABiTS™)
Authors: Kang Sukill , Goyal Amit , Leonard Keith J. , Rutter Noel A. , Lee Dominic F. , Kroeger Donald M. , Paranthaman Mariappan Parans
Published: September 2005

YBa2Cu3O7−δ (YBCO) films with thicknesses ranging from 1.0 to 6.4 μm were deposited by pulsed laser deposition on rolling‐assisted biaxially textured substrates (RABiTS). The RABiTS were of the configuration CeO2/YSZ/Y2O3/Ni–3 at.% W. As the YBCO film thickness increased, Ic continued to increase and reached ∼300 A/cm width for a 4.3 μm‐thick YBCO film. Commonly observed mechanisms for Jc decrease with increasing YBCO film thickness were not observed. Homogeneous microstructures obtained in even the thickest YBCO films, suggest that the Ic/width can still be enhanced considerably.
Orientation and Grain Boundary Microstructure of Alumina in Al/Al2O3 Composites Produced by Reactive Metal Penetration
Authors: Murthy Varanasi S. R. , Kawahara Koichi , Saito Yasuko , Matsuzaki Takashi , Watanabe Tadao
Published: September 2005

The orientation and grain boundary microstructure of alumina in reactive metal penetration Al/Al2O3 composites are studied using orientation imaging microscopy and the results are compared with those of sintered polycrystalline Al2O3. The interconnected Al2O3 in the composite material is separated by Σ3 boundaries (twins) with a 60° rotation around the [0001] direction. A high frequency (∼100%) of Σ3 coincidence boundaries in composite alumina is remarkable since only ∼12% of boundaries in a sintered polycrystalline Al2O3 are of special nature. The coincidence boundaries in the in situ alumina grow in a coherent and faceted manner.
Synthesis of Ultrahigh‐Temperature Si–B–C–N Ceramic from Polymeric Waste Gas
Authors: Wang Zhi‐Chang , Gerstel Peter , Kaiser Gerhard , Bill Joachim , Aldinger Fritz
Published: September 2005

A “green” route to ultrahigh‐temperature Si–B–C–N ceramic from vacuum‐degassing waste gas of polyborosilazane {B[C2H4Si(CH3)NH]3}n (T2‐1) has been developed. After gas‐to‐gel transformation, an amorphous ceramic Si5.3B1.0C19N3.7 was derived from the gel by dehydrocoupling and polymer‐to‐ceramic transformation. The ceramic started to form a nanostructure at 1700°C and resisted thermal degradation up to 2200°C in argon. This suggests that vacuum‐degassing waste gases of polymer precursors may be perfect raw materials for various advanced ceramics.
Production of Nanocrystalline Titanium Nitride Powder by Atmospheric Microwave Plasma Torch in Hydrogen/Nitrogen Gas
Authors: Shin Dong Hun , Hong Yong Cheol , Uhm Han Sup
Published: September 2005

Nanocrystalline titanium nitride (TiN) particles were directly synthesized in an atmospheric microwave plasma torch, using gas‐phase titanium tetrachloride (TiCl4), with N2 and H2 as reactants. The gas‐phase TiCl4 was injected with H2 gas into the microwave plasma‐torch flame generated by N2 swirl gas, and then the dark blue powders were deposited on the inner wall of the quartz tube. The synthesized powder samples were analyzed by scanning electron microscopy (SEM), SEM‐EDX, X‐ray diffractometer (XRD), transmission electron microscopy, and FT‐Raman. The average crystallite sizes of TiN measured from XRD patterns decreased from 15.5 to 11.6 nm, as the flow rate of H2 injected into the microwave plasma torch increased from 0.03 to 0.3 liters per minute.
High‐Temperature Phase Equilibria of the Magnesium–Niobium–Titanate System
Authors: Mangham Robert I. , Petuskey William T.
Published: September 2005

The high‐temperature phase equilibria for the MgO–Nb2O5–TiO2 system have been determined in air and at 1 atm O2. Three isothermal sections, namely 1450°, 1350°, and 1250°C, were determined experimentally. From this, the 1000°C isothermal section was deduced by extrapolation. Throughout each diagram, most compounds were found to have an extended range of solubility, each exhibiting the same substitutional pattern of the combination 1/3(MgNb2)4+ replacing Ti4+. Furthermore, entropic stabilization because of cation mixing is evident for all phases except for the columbite solid solution, in which case the solid solution range decreased with increasing temperature.
Residual Stresses and Their Effects on the Durability of Environmental Barrier Coatings for SiC Ceramics
Authors: Lee Kang N. , Eldridge Jeffrey I. , Robinson Raymond C.
Published: September 2005

Qualitative residual stresses in current environmental barrier coatings (EBCs) were inferred from the curvature of EBC‐coated SiC wafers, and the effects of EBC stresses on the durability of EBC‐coated SiC were evaluated. The magnitude of substrate curvature correlated fairly well with the EBC–SiC coefficient of thermal expansion (CTE) mismatch, EBC modulus, and thermally induced physical changes in EBC. BSAS (1−xBaO·xSrO·Al2O3·2SiO2, 0≤x≤1) components in the current EBCs, i.e., Si/mullite or mullite+BSAS/BSAS or yttria‐stabilized zirconia (YSZ: ZrO2–8 wt% Y2O3), were the most beneficial for reducing the EBC stress in as‐sprayed as well as in post‐exposure EBCs. The reduced stress was attributed to the low modulus of BSAS. The addition of a YSZ top coat significantly increased the substrate curvature because of its high CTE and sintering in thermal exposures. There were clear correlations between the wafer curvature and the EBC durability. The Si/mullite+20 wt% BSAS/BSAS EBC maintained excellent adherence, protecting the SiC substrate from oxidation, while the Si/mullite+20 wt% BSAS/YSZ EBC suffered delamination, leading to severe oxidation of the SiC substrate, after a 100 h −1300°C exposure in a high‐pressure burner rig.
Optical Properties of Hydrothermally Synthesized Hematite Particulate Pigments
Authors: Wang Jun , White William B. , Adair James H.
Published: September 2005

Iron oxide hematite particles with various shapes (platelet, polyhedron, pseudocube, and peanut‐like) have been synthesized by hydrothermal treatment of a Fe(OH)xOy precursor under various conditions. The size and shape of hematite particles can be adjusted by carefully controlling the processing parameters such as holding time, temperature, and adsorption ions present in the system. The nearly monosized α‐Fe2O3 platelets possess face diameters of approximately 3 μm and a thickness of 0.5 μm under a scanning electron microscope. The apparent color of the particles changes as particle size and shape varies. Munsell color notation was employed to compare the color of hematite particles with various sizes and shapes. Diffuse reflectance spectra show that a “red‐shift” of 40 nm is observed in platelet, pseudocube, and peanut‐like particles compared with conventional particles. The band at 850 nm for the 6A1→4T1 transition was split in the pseudocubic and peanut‐like particles. Raman spectra of the hematite particles also reveal that the vibrational modes of α‐Fe2O3 particles diminish as particle size decreases, and dependence of vibrational band intensity on frequency is also observed. The spectral profiles demonstrate significant difference as excitation radiation lines changes from blue (457 nm) to red (647 nm). Possible mechanisms responsible for the optical properties of hematite particles are postulated based on the findings of the experiments.
Preparation of Fine Tetragonal Barium Titanate Powder by a Microwave–Hydrothermal Process
Authors: Sun Weian , Li Junqing , Liu Wen , Li Chuiha
Published: September 2005

A microwave–hydrothermal (MH) process was performed at 240°C to prepare tetragonal BaTiO3 from TiCl4 and Ba(OH)2. No alkali hydroxide was used to avoid contaminations. MH BaTiO3 powder with a c/a ratio of 1.010 and a mean size of 180 nm was synthesized within only 9 h. The MH BaTiO3 contains a very low concentration of lattice hydroxyl group, associated with a very small lattice strain. The measured density of the MH BaTiO3 is favorably consistent with the theoretical value, and the Ba/Ti stoichiometry determined is 0.996. The formation of a tetragonal structure in BaTiO3 and the particle growth were strongly promoted by the MH process. The effects of lattice defects on the stoichiometry and the determination of transition enthalpy were discussed.
Preparation of Tubular Silicalite Membranes by Hydrothermal Synthesis with Electrophoretic Deposition as a Seeding Technique
Authors: Negishi Hideyuki , Imura Tomohiro , Kitamoto Dai , Ikegami Toru , Yanagishita Hiroshi , Okamoto Masayoshi , Idemoto Yasushi , Koura Nobuyuki , Sano Tuneji
Published: September 2005

Preparation of tubular silicalite membranes by hydrothermal synthesis with electrophoretic deposition (EPD) as a seeding technique was investigated. Two micrometers of small silicalite seeds were produced by an open‐system hydrothermal synthesis at 100°C. These seeds were dispersed in 1‐propanol and seeded on porous tubular stainless‐steel supports by EPD; it had a high productivity and uniformity. The seeded support was then hydrothermally treated, and a tubular silicalite membrane was obtained. The pervaporation performance of this membrane showed a separation factor α of 70 with a total flux of 0.35 kg·(m2·h)−1 for a 5 vol% EtOH aqueous solution at 30°C.
Potent therapeutic effect of melatonin on aging skin in pinealectomized rats
Authors: Eşrefoğlu Mukaddes , Seyhan Muammer , Gül Mehmet , Parlakpınar Hakan , Batçıoğlu Kadir , Uyumlu Burçin
Published: September 2005

Abstract:  It is generally agreed that one of the major contributors to skin aging is reactive oxygen species. As organisms reach advanced age, free radical generation increases and the activity of tissue antioxidant enzyme system decreases. Melatonin is an antioxidant and free radical scavenger. The present study was first aimed to determine the morphometric and biochemical changes caused by long‐term pinealectomy in order to investigate the role of melatonin as skin architecture. Secondly, the effect of exogenous melatonin administration on these changes was determined. Rats were pinealectomized or sham operated (control) for 6 months. Half of the pinealectomized rats were treated with 4 mg/kg melatonin during the last month of the experiment. Pinealectomy resulted in important morphometric and biochemical changes in the back, abdominal and thoracic skin. The thickness of epidermis and dermis and the number of dermal papillae and hair follicles were reduced. Melatonin administration to pinealectomized rats significantly improved these alterations in all body areas (P < 0.005). On the contrary, in pinealectomized rats the levels of antioxidant enzymes, catalase and glutathione peroxidase were decreased. Melatonin restored the levels of these enzymes. The pinealectomy‐induced increases in lipid peroxidation in the abdominal and thoracic skin were significantly reduced by melatonin treatment (P < 0.005 and 0.01 respectively). These results suggest that melatonin is highly efficient anti‐aging factor and, as melatonin levels decrease with age, melatonin treatment may reduce age‐related skin changes.
Melatonin protects against ischemia/reperfusion injury in skeletal muscle
Authors: Erkanlı Korhan , Kayalar Nihan , Erkanlı Gözde , Ercan Feriha , Sener Göksel , Kırali Kaan
Published: September 2005

Abstract:  Melatonin has been shown to diminish ischemia‐reperfusion (I/R) injury in many tissues. The main aim of this study was to evaluate the protective antioxidant effect of melatonin in skeletal muscle during I/R injury. Wistar albino rats were randomly divided into three groups. Hindlimb ischemia was achieved by clamping the common femoral artery in two groups but not in control group. Limbs were rendered ischemic for 1.5 hr; at the end of the reperfusion period of 1.5 hr muscle tissue samples were taken for the histological evaluation and biochemical analysis. Melatonin (10 mg/kg) was injected i.p. in the I/R + Mel group at the onset of ischemia whereas the vehicle solution was injected in the I/R group. In I/R + Mel group histological damage was significantly less than in the I/R group (P < 0.001). In the I/R + Mel group, the mean malonedialdehyde level was lower than in the I/R group (P < 0.01) and was quite near to the levels in the control group (P > 0.05). Glutathione levels were found to be reduced in the I/R group compared with the control (P < 0.01) and I/R + Mel group (P < 0.01). Melatonin has a protective effect against I/R injury in skeletal muscle and may reduce the incidence of compartment syndrome, especially after acute or chronic peripheral arterial occlusions.
Reactions of the melatonin metabolite AMK (N1‐acetyl‐5‐methoxykynuramine) with reactive nitrogen species: Formation of novel compounds, 3‐acetamidomethyl‐6‐methoxycinnolinone and 3‐nitro‐AMK
Authors: Guenther Anna L. , Schmidt Sonja I. , Laatsch Hartmut , Fotso Serge , Ness Heiko , Ressmeyer Anna‐Rebekka , Poeggeler Burkhard , Hardeland Rüdiger
Published: September 2005

Abstract:  The melatonin metabolite N1‐acetyl‐5‐methoxykynuramine (AMK) was found to be unstable in air when adsorbed on a thin‐layer silica gel chromatography plate, a result that is in good agreement with the relatively high reactivity of this compound. Three novel main products were separated from the reaction mixture and identified by mass spectrometry and nuclear magnetic resonance data as: (i) 3‐acetamidomethyl‐6‐methoxycinnolinone (AMMC), (ii) 3‐nitro‐AMK (AMNK, N1‐acetyl‐5‐methoxy‐3‐nitrokynuramine), and (iii) N‐[2‐(6‐methoxyquinazolin‐4‐yl)‐ethyl]‐acetamide (MQA). AMMC and AMNK are shown to be nonenzymatically formed also in solution, by nitric oxide (NO) in the first case, and by a mixture of peroxynitrite and hydrogen carbonate, in the second one. The use of three different NO donors, PAPA‐NONOate, S‐nitroso‐N‐acetylpenicillamine and sodium nitroprussiate led to essentially the same results, with regard to a highly preferential formation of AMMC; AMNK was not detected in these reaction systems. Competition experiments with the NO scavenger N‐acetylcysteine indicate a somewhat lower reactivity compared with the competitor. Peroxynitrite led to AMNK formation in the presence of physiological concentrations of hydrogen carbonate at pH 7.4, but not in its absence, indicating that nitration involves a mixture of carbonate radicals and NO2, formed from the peroxynitrite‐CO2 adduct. No AMMC was detected after AMK exposure to peroxynitrite. Both AMNK and AMMC exhibited a much lower reactivity toward 2,2′‐azino‐bis‐(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS) cation radicals than did AMK. In a competition assay for hydroxyl radicals, AMMC showed prooxidant properties, whereas AMNK was a moderate antioxidant. AMMC and AMNK should represent relatively stable physiological products, although their rates of synthesis are still unknown and may be low. Formation of these compounds may contribute to the disappearance of AMK from tissues and body fluids.
Melatonin neutralizes neurotoxicity induced by quinolinic acid in brain tissue culture
Authors: Vega‐Naredo Ignacio , Poeggeler Burkhard , Sierra‐Sánchez Verónica , Caballero Beatriz , Tomás‐Zapico Cristina , Álvarez‐García Oscar , Tolivia Delio , Rodríguez‐Colunga María J. , Coto‐Montes Ana
Published: September 2005

Abstract: Quinolinic acid is a well‐known excitotoxin that induces oxidative stress and damage. In the present study, oxidative damage to biomolecules was followed by measuring lipid peroxidation and protein carbonyl formation in rat brain tissue culture over a period of 24 hr of exposure to this prooxidant agent at a concentration of 0.5 mm. Quinolinic acid enhanced lipid peroxidation in an early stage of tissue culture, and protein carbonyl at a later stage. These data confirm and extend previous studies demonstrating that quinolinic acid can induce significant oxidative damage. Melatonin, an antioxidant and neuroprotective agent with multiple actions as a radical scavenger and signaling molecule, completely prevented these prooxidant actions of quinolinic acid at a concentration of 1 mm. Morphological lesions and neurotoxicity induced by quinolinic acid were evaluated by light microscopy. Quinolinic acid produced extensive apoptosis/necrosis which was significantly attenuated by melatonin. Cotreatment with melatonin exerted a profound protective effect antagonizing the neurotoxicity induced by quinolinic acid. Glutathione reductase and catalase activities were increased by quinolinic acid and these effects were antagonized by melatonin. Furthermore, melatonin induced superoxide dismutase activity. Quinolinic acid and melatonin acted independently and by different mechanisms in modulating antioxidant enzyme activities. Our findings using quinolinic acid and melatonin clearly demonstrate that such changes should always be seen in the context of oxidative neurotoxicity and antioxidant neuroprotection.
Products of tryptophan catabolism induce Ca2+ release and modulate the cell cycle of Plasmodium falciparum malaria parasites
Authors: Beraldo Flávio H. , Garcia Célia R. S.
Published: September 2005

Abstract:  Intraerythrocytic malaria parasites develop in a highly synchronous manner. We have previously shown that the host hormone melatonin regulates the circadian rhythm of the rodent malaria parasite, Plasmodium chabaudi, through a Ca2+‐based mechanism. Here we show that melatonin and other molecules derived from tryptophan, i.e. N‐acetylserotonin, serotonin and tryptamine, also modulate the cell cycle of human malaria parasite P. falciparum by inducing an increase in cytosolic free Ca2+. This occurs independently of the extracellular Ca2+ concentration, indicating that these molecules induce Ca2+ mobilization from intracellular stores in the trophozoite. This in turn leads to an increase in the proportion of schizonts. The effects of the indolamines in increasing cytosolic free Ca2+ and modulating the parasite cell cycle are both abrogated by an antagonist of the melatonin receptor, luzindole, and by the phospholipase inhibitor, U73122.
Effect of melatonin on secreted and induced matrix metalloproteinase‐9 and ‐2 activity during prevention of indomethacin‐induced gastric ulcer
Authors: Ganguly Krishnendu , Maity Pallab , Reiter Russel J , Swarnakar Snehasikta
Published: September 2005

Abstract:  Matrix metalloproteinases (MMPs) maintain the crucial role in physiological turnover of extracellular matrix (ECM) proteins in gastric tissues. However, a little is known about the relationship of MMPs with ECM degradation during gastric ulceration and ECM remodeling during healing. Our objective was to investigate the effect of melatonin (N‐acetyl‐5 methoxytryptamine) on the regulation of MMP‐9 and MMP‐2 activity during prevention of gastric ulcer. In the present study, biochemical and zymographic methods were used to analyze the mechanism of melatonin in indomethacin‐induced gastric ulcer in a rat model. Our studies reveal that melatonin dose‐dependently downregulates the expression and secretion of pro‐MMP‐9 which is induced (approximately 10‐fold) during indomethacin‐induced gastric ulceration. Furthermore, melatonin prevents gastric ulceration in a dose‐dependent manner through upregulation (approximately two‐ to threefold) of both pro‐MMP‐2 and active MMP‐2 at the level of induction as well as secretion. It also prevents gastric ulcers by blocking glutathione depletion and lipid peroxidation in cytosolic and microsomal fractions. The novel findings of this study are attributed to the attenuation of the pro‐MMP‐9 and increase of MMP‐2 activity by pretreatment with melatonin. The finding defines one of the MMP‐mediated pathways for melatonin's action in gastric ulcer.
Effect of melatonin on lipid peroxidation, glutathione and glutathione‐dependent enzyme activities in experimental otitis media with effusion in guinea pigs
Authors: Taysi Seyithan , Ucuncu Harun , Elmastas Mahfuz , Aktan Bulent , Emin Buyukokuroglu M.
Published: September 2005

Abstract:  Melatonin plays a role in the prevention of oxidative damage. In the present study, we investigated whether the increased oxidative stress in experimental otitis media with effusion (OME) induced by histamine is reflected in erythrocytes and middle ear effusion fluid. Lipid peroxidation in effusion fluid was measured to determine the effects of melatonin on oxidative stress. Erythrocyte and middle ear effusion malondialdehyde (MDA) levels, erythrocyte glutathione (GSH) levels and glutathione peroxidase (GPx), glutathione reductase (GRd) and glutathione‐S‐transferase (GST) activities were measured in three groups of six guinea pigs each at 3 hr after the injection of 0.1 mL of histamine (or saline) into the middle ear. In erythrocyte and middle ear effusion samples, MDA levels showed a significant increase in guinea pigs with experimental OME group when compared with the control animals. Erythrocyte GPx, GST, GRd activities and GSH levels significantly reduced in experimental OME guinea pigs when compared with the control and melatonin‐treated animals. Erythrocyte GPx activity also significantly increased after melatonin treatment when compared with the control group. These findings suggest that reactive oxygen species play a role in histamine‐induced OME. Pretreatment with melatonin increases antioxidant enzyme activities and reduced formation of MDA, an indicator of lipid peroxidation, in histamine‐induced OME.
Melatonin stimulates inositol‐1,4,5‐trisphosphate and Ca2+release from INS1 insulinoma cells
Authors: Bach Andreas G. , Wolgast Sabine , Mühlbauer Eckhard , Peschke Elmar
Published: September 2005

Abstract: The effects of melatonin in mammalian cells are exerted via specific receptors or are related to its free radical scavenging activity. It has previously been reported that melatonin inhibits insulin secretion in the pancreatic islets of the rat and in rat insulinoma INS1 cells via Gi‐protein‐coupled MT1 receptors and the cyclic adenosine 3′,5′‐monophosphate pathway. However, the inositol‐1,4,5‐trisphosphate (IP3) pathway is involved in the insulin secretory response as well, and the melatonin signal may play a part in its regulation. This paper addresses the involvement of the second messengers IP3and intracellular Ca2+([Ca2+]i) in the signalling cascade of melatonin in the rat insulinoma INS1 cell, a model for the pancreaticβ‐cell. For this purpose melatonin at concentrations ranging from 1 to 100 nmol/L, carbachol and the nonselective melatonin receptor antagonist luzindole were used to stimulate INS1 cell batches, followed by an IP3‐mass assay and Ca2+imaging. Molecular biological studies relating to the mRNA of IP3receptor (IP3R) subtypes and their relative abundance in INS1 cells showed expression of IP3R‐1, IP3R‐2 and IP3R‐3 mRNA. In conclusion, we found that in rat insulinoma INS1 cells there is a dose‐dependent stimulation of IP3release by melatonin, which is accompanied by a likewise transient increase in [Ca2+]iconcentrations. The melatonin effect observed mimics carbachol action. It can be abolished by 30 μmol/L luzindole and is sustained in Ca2+‐free medium, suggesting a mechanism that includes the depletion of Ca2+from intracellular stores.
The in vivo effect of melatonin on cellular activation processes in human blood during strenuous physical exercise
Authors: Johe Paul D. , Østerud Bjarne
Published: September 2005

Abstract:  Melatonin has been reported to have anti‐ as well as pro‐inflammatory properties. Because physical stress is associated with the activation of blood cells, the present study examines melatonin's role in exercise‐induced cell activation processes. Eight healthy volunteers (aged 20–62 yr, mean = 31), exercised on an ‘Ergometric’ bike for 30 min at 80% of their calculated maximum pulse rate. Blood samples were taken just before melatonin administration, directly after exercise, and 2 hr after exercise completion. Cytokine and eicosanoid parameters were measured in plasma from blood stimulated with lipopolysaccharide (LPS) for 2 hr whereas tissue factor (TF) activity was measured in isolated monocytes. Melatonin significantly decreased LPS‐induced TF activity by 48% (P < 0.01) directly after exercise, and a 44% reduction was seen 2 hr later (P < 0.02). Furthermore, melatonin significantly reduced the lymphocyte count rise produced directly after exercising by more than 30% (P < 0.01). A trend was also seen for melatonin suppressing the increase of WBC by around 10% and to strengthen the platelet increase by about 8% after physical stress. Melatonin also significantly lowered RBC and hemoglobin counts by 5 and 3–4% during exercise (P < 0.005 and <0.02 respectively). Two hours after exercise, melatonin tended to lower leukotriene B4 levels by 30%. Interleukin‐8 and tumor necrosis factor‐α levels tended to be lower in individuals who had taken melatonin following hard physical activity and a larger sample size may show significance. Thromboxane B2 production seemed unaffected by melatonin during exercise. In conclusion, in vivo intake of melatonin appears to suppress LPS‐induced activation of monocytes in whole blood reactions associated with physical exercise and facilitates the down‐regulation of inflammatory mediators.
Lack of association between pro‐inflammatory cytokine (IL‐6, IL‐8 and TNF‐α) gene polymorphisms and Graves’ disease
Authors: Chen R.‐H. , Chen W.‐C. , Wang T.‐Y. , Tsai C.‐H. , Tsai F.‐J.
Published: September 2005

Graves’ disease (GD) is a common, autoimmune disease involving the thyroid gland, and it has been previously suggested that pro‐inflammatory cytokines are involved in the disease's pathogenesis. The aim of this study was to test whether the interleukin (IL)‐6 gene promoter region, or tumour necrosis factor (TNF)‐α or IL‐8 gene 3′‐untranslated region (3′‐UTR) polymorphisms could provide useful genetic markers for an individual's susceptibility to GD. A normal control group of 60 healthy people and 95 patients featuring GD were examined. Polymerase chain reaction (PCR)‐based restriction analysis was performed for the three gene polymorphisms using endonucleases BsrBI, NcoI and ApaLI, respectively. We found no significant difference between the frequencies of genotype and allelic variants for the IL‐6 gene promoter (−572 G/C), the TNF‐α gene promoter (−308 A/G) and the IL‐8 gene 3′‐UTR (2767 A/G) for GD patients and for normal controls. Cytokines are a large group of proteins that may elicit multiple effects upon immunological reactions. It still appears to be very worthwhile to continue to aggressively search for cytokine gene polymorphisms in order to predict the development of such disease.
ICAM‐1 polymorphisms and development of cutaneous malignant melanoma
Authors: Howell W. M. , Rose‐Zerilli M. J. , Theaker J. M. , Bateman A. C.
Published: September 2005

Tumour growth in cutaneous malignant melanoma (CMM) is mediated by cell adhesion molecules, including intercellular adhesion molecule‐1 (ICAM‐1). ICAM‐1 expression is associated with increasing Breslow thickness of vertical growth‐phase tumours and, in patients with stage 1 disease, may be associated with disease free and patient survival. In this study we have investigated whether two single nucleotide polymorphisms (SNPs) in the ICAM‐1 gene encoding amino acid substitutions in codons 241 and 469 of the expressed ICAM‐1 molecule are associated with susceptibility to and markers of prognosis (including tumour Breslow thickness) in CMM. A total of 164 CMM patients and 264 cancer‐free controls were genotyped for these SNPs by the 5′ nuclease assay for allelic discrimination (TaqMan®). No genotypes showed any significant associations with CMM susceptibility, although there was a non‐significant increase in frequency of the ICAM‐1 469 AA genotype among CMM patients vs. controls (38.4% vs. 29.9%; P = 0.11). However, the ICAM‐1 241 GG genotype was significantly decreased in frequency among patients with primary invasive tumours of greater Breslow thickness (72.5% vs. 91.2%; P = 0.013; OR = 0.25 (0.072–0.85)). These results provide no evidence for a role for the ICAM‐1 codon 241 and 469 SNPs in determining susceptibility to CMM, but provide preliminary evidence that the role of ICAM‐1 polymorphism in modulating tumour growth in CMM requires further investigation in a larger study group.
Alternative splicing of IL‐24 in melanocytes by deletion of exons 3 and 5
Authors: Allen M. , Pratscher B. , Krepler C. , Frei K. , Schöfer C. , Pehamberger H. , Müller M. , Lucas T.
Published: September 2005

Two novel interleukin‐24 (IL‐24) splice variants were identified in normal human melanocytes by sequencing cloned polymerase chain reaction (PCR) products that are not expressed in metastatic melanoma. These gene products have been generated by differential skipping of exons 3 (IL‐24 delE3) and 5 (IL‐24 delE5). IL‐24 delE3 has limited sequence identity to the IL‐24‐interacting protein mda‐7s, and IL‐24 delE5 is homologous to IL‐24.