bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Flask Closure and Flask Cooling Methods on Tooth Movement in Maxillary Dentures
Authors: Consani Rafael L.X. , Domitti Saide S. , Mesquita Marcelo F. , Consani Simonides 
Published: July 2006

Purpose: This study investigated the tooth movement of standardized simulated dentures processed by traditional closure or the new Rafael Saide (RS) tension system when cooled in the curing water itself or in curing water followed by bench storage for 3 hours.
Materials and Methods: Forty stone casts were formed from a mold of an edentulous maxillary arch. The wax denture record bases were made on the casts; the height of the wax rim occlusion was 20 mm in the labial sulcus of the cast and 10 mm in the posterior region. The upper stone cast was mounted on a Mondial 4000 semi‐adjustable articulator with wax rim interocclusal references in relation to the lower stone cast teeth. Metallic pins were placed in the incisal border of the maxillary central incisors (I), labial cusp of the first premolars (PM), and mesiolabial cusp of the second molars (M). The incisor‐to‐incisor (I–I), premolar‐to‐premolar (PM–PM), and molar‐to‐molar (M–M) transversal distances and left incisor‐to‐left molar (LI–LM), and right incisor‐to‐right molar (RI–RM) anteroposterior distances were measured before and after denture polymerization with an optical microscope with a tolerance of 0.0005 mm. For traditional closure, the dentures were flasked conventionally in standard metallic flasks, which were afterward placed in spring clamps. For the new RS system closure, the flasks were pressed between the metallic plates of the tension system after the final closure. The Clássico heat‐polymerizing acrylic resin dough was packed in the flasks under a final packing pressure of 1.250 kgf. Twelve hours after flask closure, the dentures were polymerized in a moist heat‐polymerizing cycle for 9 hours at 74°C. The denture was deflasked after cooling in the water of the polymerizing cycle (groups A and C) or in the water of the polymerizing cycle and then bench‐stored for 3 hours (groups B and D). Collected data were analyzed with analysis of variance and Tukey's test (p< 0.05).
Results: There was no statistically significant difference (p> 0.05) between the conventional and new RS system closure methods for the transversal distances after polymerization in all studied groups. The anteroposterior distances did not change with deflasking after water bath cooling. There were statistically significant differences (p< 0.05) in the anteroposterior distances with deflasking after water bath cooling and then bench storage for 3 hours.
Conclusion: Tooth movement was similar in dentures processed by traditional closure and by the new RS tension system, with the exception of the anteroposterior distances when the flasks were cooled in their own curing water and bench‐stored for 3 hours.
Effect of Disinfectants on the Hardness and Roughness of Reline Acrylic Resins
Authors: Azevedo Andrea , Machado Ana Lucia , Vergani Carlos Eduardo , Giampaolo Eunice Teresinha , Pavarina Ana Cláudia , Magnani Romeo 
Published: July 2006

Purpose: Potential effects on hardness and roughness of a necessary and effective disinfecting regimen (1% sodium hypocholorite and 4% chlorhexidine) were investigated for two hard chairside reline resins versus a heat‐polymerizing denture base acrylic resin.
Materials and Methods: Two standard hard chairside reliners (Kooliner and Duraliner II), one heat‐treated chairside reliner (Duraliner II +10 minutes in water at 55°C), and one standard denture base material (Lucitone 550) were exposed to two disinfecting solutions (1% sodium hypochlorite; 4% chlorhexidine gluconate), and tested for two surface properties [Vickers hardness number (VHN, kg/mm2); Roughness (Ra, μm)] for different times and conditions (1 hour after production, after 48 hours at 37 ± 2°C in water, after two disinfection cycles, after 7 days in disinfection solutions, after 7 days in water only). For each experimental condition, eight specimens were made from each material. Data were analyzed by analysis of variance followed by Tukey's test, and Student's t‐test (p= 0.05).
Results: For Kooliner (from 6.2 ± 0.3 to 6.5 ± 0.5 VHN) and Lucitone 550 (from 16.5 ± 0.4 to 18.4 ± 1.7 VHN), no significant changes in hardness were observed either after the disinfection or after 7 days of immersion, regardless of the disinfectant solution used. For Duraliner II (from 4.0 ± 0.1 to 4.2 ± 0.1 VHN), with and without heat treatment, a small but significant increase in hardness was observed for the specimens immersed in the disinfectant solutions for 7 days (from 4.3 ± 0.2 to 4.8 ± 0.5 VHN). All materials showed no significant change in roughness (Kooliner: from 0.13 ± 0.05 to 0.48 ± 0.24 μm; Duraliner II, with and without heat treatment: from 0.15 ± 0.04 to 0.29 ± 0.07 μm; Lucitone 550: from 0.44 ± 0.19 to 0.49 ± 0.15 μm) after disinfection and after storage in water for 7 days.
Conclusions: The disinfectant solutions, 1% sodium hypochlorite and 4% chlorhexidine gluconate, caused no apparent damage on hardness and roughness of the materials evaluated.
Obscure Syncope and the Sick Sinus Syndrome
Authors: LISTER JOHN W. , GOSSELIN ARTHUR J. , SWAYE PAUL S. 
Published: July 2006

This report describes a 25‐year‐old vigorous young man who had a history of eight years of near syncope and syncope of unknown etiology. Repeat in‐hospital observation and laboratory electrophysiologic functional testing did not elucidate the origin of the symptoms. Prolonged Holler monitoring finally showed that the syncopal attacks were caused by a sick sinus syndrome (SSS). On electrophysiologic study, a concealed rate‐dependent unidirectional antegrade accessory A‐V pathway (AP) was found to be present. The AP was an incidental finding and was unrelated to the patient's symptoms.The symptomatic SSS may occur in the young as well as in the elderly. Sinoatrial dysfunction may be intermittent and difficult to detect, may cause severe symptoms, and may even be life‐threatening. Prior to definitive therapy (such as the permanent implantation of a pacemaker), the importance of relating symptoms to a rhythm disturbance has been stressed. In cases where the cause of the symptoms is not obvious, this is best accomplished by continuous Holter monitoring.
The Automatic Rate Adjustment Pacemaker. The Possibilities of Rate Hysteresis
Authors: PRESTON THOMAS A. , PRESTON ALBERT W. 
Published: July 2006

Since the first use of pacemakers there have been attempts to regulate the fixed, or basic rate of implanted pulse generators: Earlier models employed the use of magnets or percutaneous needles to change the pacemaker rate after implantation. A recent development is the programmable pacemaker, which utilizes external electromagnetic signals to alter the basic rate.A series of engineering advances have resulted in automatic pacemaker rate changes, as first embodied in the hysteresis pacemaker. Notable modifications of the basic hysteresis concept include gradual pacemaker rate changes, and variable hysteresis or rate changes dependent on electrophysiologic events. Many of these technical advances are unknown to physicians; but are disclosed in patents.In general, negative hysteresis favors emergence of underlying non‐pacer rhythms, whereas positive hysteresis suppresses underlying rhythms of any type. The automatic rate adjustment pacemaker represents an attempt to derive the advantages of negative hysteresis while eliminating the disadvantages of abrupt rate changes. The unit automatically searches for a sinus rhythm slower than the basic pacing rate, by periodically gradually slowing its rate to a lower level.
An Appraisal of Radioisotope Fueled Pacemakers After 5 Years
Authors: PARSONNET VICTOR , MYERS GEORGE H. , MANHARDT MARJORIE 
Published: July 2006

Summary and ConclusionsPersonal observation of 131 radioisotope‐powered pulse generators in 120 patients over a period of 5 years has confirmed the expectations of the developers. Actuarial survival of the pulse generator at 5 years was 96 percent. There were only two cases of component failure (1.5 percent) and no battery failures.13To date there has been no evident toxicity from radiation effects. The total cost of pacing is less with nuclear units than with lithium or with mercury‐zinc powered models.Factors, limiting the use of the pacer are the persistence of nonbattery problems that require premature reoperation, and the unavailability of a truly “modern” pulse generator.Because the nuclear pacers have proved to be effective, relatively inexpensive, and apparently safe, we believe that continued clinical use is justified; the manufacturers, however, should modify the present units by incorporating fully programmable circuits in a pulse generator package much reduced in size.
His Bundle Electrogram in Patients with Acute Myocardial Infarction
Authors: GOULD LAWRENCE , REDDY C.V.R. , KIM S.G. , OH K.C. 
Published: July 2006

Thirty‐seven patients with acute myocardial infarction complicated by atripventricular or bundle branch block, or a combingtioh of both, had His bundle electrogram studies performed during their stay in the coronary care unit. The acute mortality of the 14 patients with a complicating bundle branch block was 50%. Pump failure was the main cause of death. Three patients in this group had a prolonged H‐V interval and one patient had a split bundle of His. The presence or absence of a prolonged H‐V interval did not affect mortality in this group of patients.The acute mortality of the 16 patients with an inferior wall myocardial infarction was 6% The H‐V interval was normal in all but one of these patients. The atrioventricular block was caused by a proximal block in all cases.The acute mortality of the seven patients with an anterior wall myocardial infarction was 29%. The H‐V interval was prolonged in two of seven patients. Pump failure was the acute cause of the deaths. The presence or absence of a prolonged H‐V interval did not affect mortality in this group of patients.
The Use of QT Interval to Determine Pacing Rate: Early Clinical Experience
Authors: RICKARDS A.F. , DONALDSON R.M. , THALEN H.J.Th. 
Published: July 2006

Malgré la disponibilité de stimulateurs du lype physlologique, il restent des inconvenients inhérenls à leur fonctionnement. En théorie, les sfimulaleurs synchrones de ľoreillette (VDD ou DDD) sont ideal, mais en pratique leur performances sont limitées pur un fourchelte assez etroite des frequences cardioques chez un certain nombre de majades. Nous décrivons donc le système TX qui incorpore à la fois la stimulation ventriculaire, et le recueil de ľonde T déterminé par ľespace QT. Ge stimulateur TX distingue entre tachycardies physiologiques et pathologiques, et fournit un rythme asservi même en ľabsence ?activité auriculaire.Despite the current availability of physiologic pacing systems, there remain distinct disadvantages associaled with their operation. Although in theory the atrial synchronous pacemaker (VDD or DDD) is the ideal system, in practice it performs satisfoctorily over a very limited range of heart rates in a limited number of individuals. We describe the TX system which incorporates ventricular pacing and is driven by T wave sensing determined by the QT interval. This pacemaker can distinguish between physiologic and pothologic tachycardias while providing an almost unlimited rate response even in the presence of on unresponsive atrium.
Pseudomalfunctions of Dual‐Chamber Pacemakers
Authors: PARSONNET VICTOR , BERNSTEIN ALAN D. 
Published: July 2006

La prolifération de la stimulation auriculoventriculaire a crée de nombreux cas de “pseudo‐dysfonctionnemenl” du stimulateur. En ce qui concerne ľinterpretation electrocardiographique, il est devenu parfois impossible de faire la distinction entre normal et anormal. La classification et les critères de ces phénomenes sont décrits. Il semble que seule la connaissance parfaite du fonctionnement de cheque stimulateur préviendra la fausse interprétation des tracés éléctrocardiographiques.The proliferation of dual‐chamber pacemakers has created a host of electrocardiography problems relating to interpretation. The term “pseudomalfunction” identifies an electrocardiographic finding that looks like pacemaker malfunction but is not. Several different models of dual‐chamber pacemakers, which are either presently available or in clinical evaluation, produce different types of pseudomalfunc‐tions. These are classified and described. Intimate knowledge of individual pacemaker characteristics is required for proper evaluation of these units.
Atrial Synchronous Ventricular Inhibited Pacing (VDD): An Underutilized Mode of Pacing
Authors: MESSENGER JOHN C. , GREENBERG PAUL S. , WARREN JAY , CASTELLANET MARK J. 
Published: July 2006

Après ľintroduction de la stimulation en VAT, le mode stimulation en VDD représente un progrés. Ses bénéfices physiologiques sont maintenant bien prouvés alors que cette stimulation n'est utilisée que dans 1 % des cas. Les progrés de la program‐mation de la période refractaire auriculaire permettant de maitriser les tachycardies induites laissent espérer une augmentation du pourcentage ?utilisation du mode de stimulation en VDD chez les malades porteurs ?un bloc de haul degré induit par ľeffort et avec fonction sinusale stable.The design of atrial synchronous, ventricular inhibited (VDD) pacemakers has been improved. Physiologic long‐term benefit has now been established, although this mode of pacing accounts for approximately one percent of implanted devices. With the ultimate control of pacemaker‐mediated lachycardia through atrial refractory programming close at hand or already available, one might expecl an increase in VDD pacing in patients with exercise‐induced high degree heart block and stable sinus node function.
Initial Results with an Activated Pyrolytic Carbon Tip Electrode
Authors: GARBEROGLIO BRUNO , INGUAGGIATO BRUNO , CHINAGLIA BENITO , CERISE OSVALDO 
Published: July 2006

Le bilan de ľétude initiale ?une nouvelle électrode en carbone est présenté. Les résultats des tests in vitro montrent une économic ?énergie meilleure qu'avec celle obtenue avec des électrodes en platine. Des études histologiques chez ľanimal montrent également une plus faibler éaction tissulaire àľinterface électrode‐coeur. Enfin, chez 121 malades porteurs de ces sondes, les courbes puissance‐duree ont des valeurs basses de rheobase. Les seuils de stimulation chronique sont constament bas. Ces resullats initiaux soulignenl la bonne performance de celte électrode au carbone.The initial results acquired from testing of a new activated pyrocarbon electrode for cardiac pacing are presented. In vitro testing has shown energy efficiency to be higher than for platinum electrodes. Histologic examination of implanted leads in animals has demonstrated a less significant tissue reaction at the tip. Finally, in a clinical trial of 121 patients with these leads, strength‐duration curves have low rheobase values. Chronic thresholds are often consistently low. These reports suggest very satisfactory results with this pyrolytic carbon electrode.
New Low Energy Transvenous Cardioverting and Pacing Electrode
Authors: BOURGEOIS I. , SMITS K. , KALLOK M. 
Published: July 2006

Une sonde endocavilaire (Medtronic Model 6880) a été developpée pour la stimulation ventriculaire, la cardioversion et pour la défibrillation endocavitaire, en utilisant un courant de basse énergie. Les résultats chez le chien aussi bien que les premières experiences chez ľhomme indiquent que cette sonde sera utile dans le traitement des tachyarythmies malignes.A new endocurdial catheter electrode (Medtronic model 6880) is described which can be used for ventricular pacing and for intrucavitary cardioversion and defibrillation. Initial results in dogs and preliminary clinical trials in humans indicate that this catheter will extend the usefulness of electrical stimulation therapy for treatment of life‐threatening tachyarrhythmias.
Central Body Temperature as a Guide to Optimal Heart Rate
Authors: GRIFFIN JERRY C. , JUTZY KENNETH R. , CLAUDE JOHN P. , KNUTTI JAMES W. 
Published: July 2006

Les stimulateurs cardiaques à fréquence fixe ne restaurent pas la fonction hémodynamique normale. Puisque un pourceniage élevé de patients porteurs ?un stimuJateur cardiaque a des anomaJies auriculaires, un outre moyen de “piloter” le pacemaker est présentér celui de la témperature du sang dans ľoreillette droite. Les sondes à enregistrement thermique mesurent la variation de température pendant ľexercice et peuvent servir de guide pour déterminer la fréquence cardiaque optimale.Studies in man suggest that fixed‐rote artificial pacemakers do not return hemodynamic function to normal, since the principal mechanism for the increase in cardiac output with exercise, increased heart rate, is not restored. Special pacemakers are available that can detect atrial activity and pace the ventricles in coordination, but nearly half of the patients receiving artificial pacemakers have abnormal atrial function fatrial fibrillation, sick sinus syndrome). This study examined the effects of exercise on the temperature of blood returning to the right atrium. Precision thermistors, placed in the right hearts of conscious dogs, recorded temperature increases of 1°C (range 0.4–1.5°C) during submaximal treadmill exercise. Temperature change correlated well with work load and changes in heart rate.
Respiratory Rate as a Determinant of Optimal Pacing Rate
Authors: ROSSI PAOLO , PLICCHI GIANNI , CANDUCCI GIANCARLO , ROGNONI GIORGIO , AINA FRANCO 
Published: July 2006

Des essais ont été faits dans ľutilisation des paramètres bialogiques pour déterminer la fréquence optimale de stimulation cardiaque. Dans cette étude, le rapport entre fréquence respiratoire et fréquence cordiaque a étéétabli chez 67 patients au cours de ľexercice. Ensuite, un système de stimulation cardiaque qui repondrait àľactivation radiotélémétrique a été posé chez onze patients. Dans deux cos un système automatique a été implanté avec succès. A present, les résultats de cette stimulation pilotée par la fréquence respiratoire sont satisfaisants.Efforts have been made to utilize biologic parameters for determining optimal cardiac pacing rates. In this study of 67 patients, a significant relationship between heart rate and respiratory rate was observed during dynamic exercise. A system using a radiofrequency activator to modify pacing rate is described. Eleven patients have received VVI pacemakers with a similar implanted radioreceiver coil. In two patients the fully automatic system has been successfully implanted. The experience with respiratory rate as a determinant of pacing rate is encouraging.
Internal Cardiac Defibrillation Threshold: Effects of Acute Ischemia
Authors: JONES DOUGLAS L. , SOHLA ANAND , KLEIN GEORGE J. 
Published: July 2006

The influence of myocardial ischemia on defibrillation success was studied using two different lead orientations in halothane‐anesthetized pigs. Ischemia was induced by ligating the left anterior descending artery in its distal third. Controls had loosely tied ligatures placed around the artery at the same site. Ventricular fibrillation was induced by electrical stimulation 30 minutes after coronary artery ligation. Defibrillation used a single truncated pulse of approximately 6 ms duration passed to either: (1) a transvenous electrode catheter (Medtronic, 6880) with the cathode in the apex of the right ventricle and the anode in the superior vena cava‐atrial junction region. or (21) the cathode in the apex of the right ventricle and a mesh plaque on the epicardium of the basal lateral left ventricle as anode. Ten seconds after the onset of ventricular fibrillation, defibrillation was attempted with increasing incremental energies until defibrillation was achieved. Fibrillation episodes were repeated at 15‐minute intervals until the minimum first shock was successful in defibrillating the animal (i.e., defibrillation threshold).The number of animals successfully defibrillated with a minimum energy above or below 30 J was not different between normal and ischemic animals for either electrode configuration (i.e., 3 out of 20 vs 1 out of 13 for the catheter and 5 out of 6 vs 6 out of 7 for the epicardial plaque, respectively). Also, the cumulative percent success as a function of defibrillation energy was similar in both the normal and ischemic groups. There was a significant reduction in the minimum energy necessary for defibrillation when passing current between the right ventricular apex and the left ventricular epicardial plaque.The present results indicate that, despite differences in lead orientations, acute ischemia in the anesthetized pig does not appear to influence defibrillation success.
Is DDD Superior to VVI Pacing in Mixed Carotid Sinus Syndrome? An Acute and Medium‐Term Study
Authors: BRIGNOLE MICHELE , SARTORE BRUNO , BARRA MAURO , MENOZZI CARLO , LOLLI GINO 
Published: July 2006

The aim of this study was to evaluate fhe importance of atrial synchronism for pacing therapy of patients with mixed carotid sinus syndrome. In 23 patients (21 m, two f: mean age 69 ± 8 years) affected by symptomatic mixed carotid sinus syndrome we performed: (1) Research of ventriculo‐atrial conduction, orthostatic hypotension and pacemaker effect; and [2] Carotid sinus massage in the standing position during VVI and DVI temporary pacing.Next, ail patients received a permanent DDD pacemaker and entered a 2 month two period single‐blind, randomized, cross‐over study on DVI/DDD versus VVI mode. During the DVI/DDD period, no syncope occurred in any patients, minor symptoms persisted in 11 (48%) of them; during VVI period syncopes recurred in three patients, symptoms requiring the withdrawal of VVI pacing and premature DVI/DDD reprogramming in eight patients, minor symptoms in 17 (74%). A comparison between 14 patients, who preferred DVI/DDD period (Group A), and the remaining nine patients who noted no preference between DVI/DDD and VVI period (Group B) was performed on the basis of the preimplant evaluation. Group A patients had a greater pacemaker effect (‐34 ± 16 mmHg vs ‐16 ± 14 mmHg) and a higher prevalence of symptomatic pacemaker effect (50% vs 0%), of ventriculo‐atrial conduction (78% vs 44%) and of orthostatic hypotension (50% vs 11%), while the entity of the systolic pressure fall caused by carotid sinus massage was similar in the two groups either during VVI mode (Group A‐51 ± 16 mmHg vs Group B‐56 ± 27 mmHg) or DVI mode (Group A‐38 ± 17 mmHg vs Group 3–45 ± 17 mmHg).Thus, we conclude that vasodepressor reflex of carotid sinus syndrome is not prevented by DVI/DDD pacing even if the loss of atrial synchronism resulting from WI pacing, by adding an important pacemaker effect, causes a more severe hemodynamic consequence.DVI/DDD pacing is more effective than VVI in 61% of patients. When pacemaker effect, ventriculoatrial conduction and orthostatic hypotension are present, VVI failure is possible, therefore DVI/DDD stimulation is indicated; on the contrary the evaluation of the vasodepressor reflex during WJ or DVI temporary pacing is of little value in the choice of the mode of pacing.