bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of High and Low Shock Energies on Sinus Electrograms Recorded via Integrated and True Bipolar Nonthoracotomy Lead Systems
Authors: GOTTLIEB CHARLES D. , SCHWARTZMAN DAVID S. , CALLANS DAVID J. , DILLON STEPHEN M. , MARCHLINSKI FRANCIS E.
Published: May 2007

Effects of Shock Energies on Electrograms. Introduction: The purpose of this investigation was to prospectively evaluate the voltage‐ and time‐dependent characteristics of a biphasic defibrillator discharge on the amplitude of the rate sensing electrogram recorded from two “integrated” and one true bipolar nonthoracotomy lead system. Prolongation of redetection time has been noted after a failed first shock with nonthoracotomy lead systems. However, prospective evaluation of the time‐ and voltage‐dependent effects of biphasic shocks on electrogram amplitude with clinically utilized lead systems has not been systematically performed.

Methods and Results: Five‐ then 30‐J R wave synchronous biphasic discharges were delivered during the supraventricular rhythm through three nonthoracotomy lead systems (Medtronic Transvene, Ventritex TVL, and CPI Endotak C 60 Series). The R wave amplitude was measured immediately postshock and for up to 1 minute. Amplitude changes were compared with reshock baseline value. A 5‐J discharge had minimal effect on the R wave amplitude recorded from the three lead systems; however. 30 J resulted in significant diminution in R wave amplitude recorded from the integrated bipolar leads (in the Endotak lead to a greater extent than the TVL lead) with minimal effects on the Transvene lead. Following a 30‐J discharge, the time constant for R wave recovery was 4.2, 14.9, and 15.3 seconds for Transvene. TVL, and Endotak 60 leads, respectively.

Conclusion: There are voltage‐ and time‐dependent reductions in postshock R wave amplitude. Integrated bipolar systems appear more affected than the “true” bipolar lead evaluated. This may he due in part, to lead design, distance of distal defibrillating surface from rate sensing cathode, and the incorporation of the defibrillating surface as the rate sensing anode. The influence of postshock R wave diminution on subsequent redetection remains speculative but may have implications for subsequent lead development.
Management of Ventricular Fibrillation with Transvenous Defibrillators Without Baseline Electrophysiologic Testing or Antiarrhythmic Drugs
Authors: LEE DOLACK G. , POOLE JEANNE E. , KUDENCHUK PETER J. , RAITT MERRITT H. , GLEVA MARYE J. , ANDERSON JILL , TROUTMAN CHARLES , BARDY GUST H.
Published: May 2007

Tranvenous Defibrillators Without EP Testing. Introduction: Baseline electrophysiologic study (EPS) is routinely performed in patients resuscitated from ventricular fibrillation (VF) to risk stratify and select patients for chronic antiarrhythmic drug therapy. The role of EP testing prior to insertion of a multiprogrammable implantable cardioverter defibrillator (ICD), however, is unclear.

Methods and Results: This study was a retrospective review of outcome in 66 survivors of an initial episode of out‐of‐hospital VF not associated with a Q wave myocardial infarction or reversible causes, treated with transvenous ICDs as first‐line therapy. Patients were excluded from the study if they had a previous history of monomorphic ventricular tachycardia (VT), a clinical history suggestive of supraventricular tachycardia, or had undergone preoperative EP testing. Fifty‐two of the patients (79%) were male with an average age of 58 ± 11 years. Coronary artery disease was present in 43 patients (66%), cardiomyopathy in 15 patients (23%), and valvular heart disease in 1 patient (1.5%). Seven patients (11%) had no detectable structural heart disease. The mean left ventricular ejection fraction was 0.40 ± 0.16. With an average follow‐up of 25 ± 12 months, survival free of death from any cause was 100%. Twenty‐three patients (35%) experienced 48 episodes of recurrent rapid VT or VF (average cycle length: 236 ± 47 msec) treated by their device. The mean time to first therapy was 223 ± 200 days. Only one of these patients also received antitachycardia pacing for two episodes of VT. One patient (1. 5%) temporarily received amiodarone after removal of an infected device that was subsequently replaced. No other patient received antiarrhythmic drug therapy.

Conclusion: After a cardiac arrest due to primary VF, select patients treated with multiprogrammable ICDs can be managed successfully without baseline EPS or antiarrhythmic drug therapy.
Functional Bundle Branch Block as a Delayed Manifestation of Retrograde Concealment in the His‐Purkinje System
Authors: GONZALEZ‐ZUELGARAY JORGE , SHEIKH SHABBIR , AKHTAR MASOOD , JAZAYERI MOHAMMAD R.
Published: May 2007

Delayed Manifestation of Retrograde HPS Concealment. Introduction: The mechanism of functional bundle branch block induced at the onset of supraventricular tachycardia (SVT) is well established. However, no data exist to address the underlying mechanism of functional bundle branch block occurring in the second beat of SVT, when the first beat is conducted with a narrow QRS morphology and preceded by ventricular stimulation.

Methods and Results: Two patients showing such a phenomenon form the basis of this report. Patient 1 with AV nodal reentrant tachycardia of the common variety persistently demonstrated functional right bundle branch block in the second SVT complex when a short train of ventricular pacing was introduced during SVT. This occurred without any discernible change in the SVT cycle length. Patient 2 bad a manifest posteroseptal accessory pathway and inducible orthodromic reentrant tachycardia. Functional bundle branch block during propagation of the second SVT complex invariably occurred either in the left bundle when SVT was induced by a bundle branch reentrant complex during premature ventricular stimulation, or in the right bundle when SVT was induced with a short train of ventricular pacing. The development of functional bundle branch block was preceded by minimal or no cycle length variations in the His‐bundle inputs.

Conclusion: These observations suggest that the type of functional bundle branch block occurring in the second SVT complex as a de novo phenomenon may be related to the relative timing of the retrograde penetration of the right versus left bundle during ventricular pacing or bundle branch reentrant complex. Therefore, due to its longest cycle length of activation and refractoriness, the earliest site of retrograde penetration is the most likely site of functional block during propagation of the second SVT complex. This delayed manifestation of retrograde concealment may provide new information regarding the electrophysiologic behavior of the His‐Purkinje system.
Temperature and Impedance Monitoring During Slow Pathway Ablation in Patients with AV Nodal Reentrant Tachycardia
Authors: STRICKBERGER S. ADAM , ZIVIN ADAM , DAOUD EMILE G. , BOGUN FRANK , HARVEY MARK , GOYAL RAJIVA , NIEBAUER MARK , MAN K. CHIN , MORADY FRED
Published: May 2007

Slow Pathway Ablation. Introduction: Successful radiofrequency ablation of an accessory pathway has been demonstrated to be associated with an electrode‐tissue interface temperature of approximately 60°C or an impedance change of −5 to −10 Ω. However, the temperature and impedance changes associated with ablation of AV nodal reentrant tachycardia (AVNRT) using the slow pathway approach have not been reported. Therefore, the purpose of this study was to define the temperature and impedance changes achieved during ablation of AVNRT.

Methods and Results: The study included 35 consecutive patients with AVNRT undergoing radiofrequency ablation of the slow pathway with a fixed power output of 32 W, and using a catheter with a thermistor bead embedded in the distal 4‐mm electrode. The procedure was successful in each patient. The steady‐state electrode‐tissue interface temperature during successful applications of energy was 48.5 ± 3.3°C (range 42° to 56°C), and the steady‐state temperature during ineffective applications was 46.8°± 5.5°C (P = 0.03). The mean impedance change during all applications of energy was −1.4 ± 2.8 ω, and did not differ significantly during effective and ineffective applications. Coagulum formation resulted during five applications (2.7%) in two patients (5.7%). There were no recurrences during 114 ± 21 days of follow‐up.

Conclusions: Successful ablation of AVNRT using fixed power output is achieved at an electrode‐tissue interface temperature of approximately 48°C and is associated with a drop in impedance of 1 to 2 ω. These findings suggest that slow pathway ablation requires less heating at the electrode‐tissue interface than does accessory pathway or AV junction ablation.
Temperature Dependence of Macroscopic L‐Type Calcium Channel Currents in Single Guinea Pig Ventricular Myocytes
Authors: ALLEN T. JEFFREY A.
Published: May 2007

Calcium Channels and Temperature. Introduction: Lowering temperature greatly reduces calcium influx through calcium channels. Studies on a number of tissues demonstrate that the peak inward current, ICa exhibits Q10 values ranging from 1.8 to 3.5; however, it remains unclear which component(s) of calcium channel gating may give rise to this large temperature sensitivity. Components of gating that may affect channel availability include phosphorylation and changes in [Ca2+)i, processes that vary in pertinence depending on the channel examined. This study addresses this problem by examining the temperature sensitivity (from 34° to 14°C) of cardiac ICa under control conditions, during attenuation or activation of protein kinase A (PKA) activity, and when intracellular [Ca2+] has been elevated.

Methods and Results: ICa was studied using the whole cell configuration of the patch clamp technique. In control, lowering temperature from 34° to 24°C resulted in a shift in the potential for maximum slope (Va and the peak current (Ymax) toward more positive membrane potentials. The Q10, values for the decrease in Ymax and the macroscopic slope conductance (Gmax), which reflects the number of available channels, were 3.15 ± 0.19 and 2.57 ± 0.13, respectively. At 0 mV the Ca2+ current decayed biexponentially, and the two time constants (T1 and T2) showed Q10 values of 1.79 ± 0.21 and 2.06 ± 038, while their contribution to the total current (I1 and I2) showed a Q10 of 5.99 ± 0.83 and 1.61 ± 0.22. In myocytes loaded with inhibitors of the PKA cycle sufficient to inhibit the increase of ICa to 1 μM isoprenaline, the Q10 values for some of the kinetic parameters were increased with the Q10 for I1 increasing to 17.06 ± 3.48. Stimulation of ICa by exposing myocytes to 1 μM isoprenaline reduced the temperature sensitivity of Ymax, Gmax, and I1, yielding respective values of 2.00 ± 0.18, 1.85 ± 0.07, and 2.04 ± 0.15. Raising [Ca2+], to enhance Ca2+i‐dependent inactivation, while affecting inactivation and activation kinetics, affected temperature sensitivity little compared to control. The Q10 for time to peak changed little under experimental conditions (2.3 to 2.4)

Conclusions: Increasing the phosphorylated states of calcium channels, but not Ca2+i‐dependent inactivation, reduces temperature sensitivity of certain gating parameters. The data suggest that the rate of the transitions between the unavailable and also between the various closed states are changed in the opposite direction to that induced by PKA‐dependent phosphorylation. Processes, e.g., inhibitory mechanisms, may be involved to maintain channels in unavailable or “unphosphorylated” states, and it may he these that contribute to the high Q10 of macroscopic channel currents.
Bezold‐Jarisch‐Like Phenomenon Induced by Radiofrequency Ablation of a Left Posteroseptal Accessory Pathway via the Coronary Sinus
Authors: SCHLÄPFER JÚRG , KAPPENBERGER LUKAS , FROMER MARTIN
Published: May 2007

RF Ablation‐Induced Bezold‐Jarisch Phenomenon. We report a case of asystole induced by radiofrequency (RF) ablation via the coronary sinus in a 35‐year‐old man suffering from symptomatic left posteroseptal accessory pathway. RF application provoked progressive slowing of the sinus rhythm, disappearance of the preexcitation, and an 8‐second period of asystole followed by atrial fibrillation. The causal mechanism proposed is a strong stimulation of va‐gal afferent pathways linked with sensory endings of the inferoposterior myocardial wall leading to a Bezold‐Jarisch‐like phenomenon.
Early Postoperative Rise in Defibrillation Threshold in Patients with Nonthoracotomy Defibrillation Lead Systems:
Authors: SCHWARTZMAN DAVID , CALLANS DAVID J. , GOTTLIEB CHARLES D. , HEO JAEKYEONG , MARCHLINSKI FRANCIS E.
Published: May 2007

DFT Rise with Nonthoracotomy Lead Systems. introduction: In patients with nonthoracotomy defibrillation lead (NTL) systems coupled with monophasic shock waveforms, the defibrillation threshold (DFT) rises early after implantation. There is little information regarding features predictive of the DFT rise, or DFT changes early after implantation of NTL systems coupled with biphasic shock waveforms.

Methods and Results: DFT measurements were performed serially at implantation, prior to hospital discharge (mean 4 ± 3 days), and at follow‐up (mean 49 ± 22 days) in 146 patients with an NTL system. Factors were assessed for association with a “clinically important” early postimplantation DFT rise, defined as a rise of ≥ 2 energy steps (2 to 4 J per step; ≥ 5 J total). A clinically important early postimplantation DFT rise occurred in 48 patients (33%). Univariate predictors of the rise included the monophasic shock waveform, the Medtronic Transvene lead system, the presence of a subcutaneous defibrillation patch, and the number of shocks delivered during the implantation procedure. However, the only independent predictor of a clinically important DFT rise was the monophasic shock waveform (F = 18, P < 0.001). For the monophasic patient group (n = 79), the incidence of a DFT rise was 53% (n = 42). For the biphasic patient group (n = 67), the incidence of a DFT rise was 9% (n = 6). The clinical characteristics of the monophasic and biphasic groups were not significantly different, nor were their DFTs at implantation. Among a subgroup of 18 consecutive patients who underwent serial DFT testing utilizing both monophasic and biphasic waveforms, the incidence of a clinically important DFT rise with monophasic (n = 9, 50%) was higher than with biphasic shocks (n = 3, 17%; P = 0.05).

Conclusion: NTL systems coupled with biphasic shock waveforms have an attenuated incidence of a clinically important DFT rise early after implantation, relative to patients with NTL systems coupled to monophasic waveforms.
A New Technique to Perform Epicardial Mapping in the Electrophysiology Laboratory
Authors: SOSA EDUARDO , SCANAVACCA MAURICIO , D'AVILA ANDRÉ , PILLEGGI EÚLVIO
Published: May 2007

Epicardial Mapping. Introduction: A possible epicardial site of origin may be the reason for unsuccessful endocardial application of radiofrequency energy to control recurrent ventricular tachycardia. This study tests the feasibility and safety of a new epicardial mapping technique in patients with Chagas’ disease and recurrent ventricular tachycardia.

Methods and Results: Epicardial mapping was performed through a pericardial puncture as an epidural introducer needle was advanced into the pericardial space under fluoroscopic guidance. Medium contrast was injected to demonstrate the position of the needle tip, and a guidewire was introduced until its tip lay within the pericardial space. A 8‐French Hemaquet was advanced and 4‐mm deflectable tip catheter introduced into the pericardial sac to map the right and left ventricular epicardium. Transthoracic echocardiographic monitoring was performed on the day of the procedure and on the day of hospital discharge. The pericardial space was reached in all patients with no complications. Electrophysiologic data suggesting the existence of an epicardial circuit was found in one patient. No complications occurred during the hospitalization period.

Conclusion: Epicardial mapping can be safely performed through a pericardial puncture in the electrophysiology laboratory.
Transvenous Defibrillation Lead Systems
Authors: GOLD MICHAEL R. , SHOROFSKY STEPHEN R.
Published: May 2007

Transvenous Defibrillation. The use of the implantable cardioverter defibrillator has grown dramatically over the past 10 years. One of the major advances in defibrillation technology is the development of transvenous lead systems. Compared with traditional epicardial lead systems, transvenous defibrillation leads reduce perioperative mortality, hospitalization, and costs. Transvenous lead systems provide reliable sensing of ventricular tachyarrhythmias, although redetection of ventricular fibrillation can be prolonged, especially with integrated lead systems. Both ramp and burst adaptive pacing are equally effective for the termination of ventricular tachycardia and are successful in up to 90% of spontaneous events. Defibrillation thresholds are higher with transvenous leads than with epicardial patches. These thresholds are reduced with the use of multiple transvenous leads, subcutaneous patches, or with reversing shock polarity. However, the development of biphasic waveforms has made the largest impact on the efficacy of these lead systems, allowing dual coil transvenous systems to be effective in about 90% of patients. Defibrillation efficacy is further enhanced and implantation simplified by the incorporation of an active pulse generator located in the left pectoral region. Active pectoral pulse generators with biphasic waveforms will be the primary lead system for new implants.
Effects of a Class III Antiarrhythmic Drug and Biphasic Shocks on the Postdefibrillation Refractory Period of Relatively Refractory Myocardium
Authors: MURAKAWA YUJI , YAMASHITA TAKESHI , AJIKI KOHSUKE , SEZAKI KAZUNORI , OMATA MASAO
Published: May 2007

Refractory Period and Defibrillation. Introduction: This study was designed to test whether the refractory state of nondepolarized myocardium is a major determinant of electrical defibrillation.

Methods and Results: Postshock recovery interval (PSRI) was estimated by measuring the residual refractory period after an appropriately timed field stimulus (1 to 16 V). The PSRI and transcardiac defibrillation threshold (DFT) were compared before and during the administration of E‐4031, a new Class III antiarrhythmic drug (group I, n = 10), or between monophasic and biphasic shocks (group 2, n = 14) in anesthetized open chest dogs. Group 1: E‐4031 reduced the DFT from 2.6 ± 0.6 J to 1.8 ± 0.6 J (P < 0.01). The PSRI increased with the increase of the applied voltage and was almost always greater during K‐4031 Infusion than at baseline. There was an inverse correlation between the changes of DFT and PSRI measured with a 14‐V stimulus (r =−0.80, P < 0.01) and a 16‐V stimulus (r =−0.80, P < 0.01). Group 2: Mean DFTs were not statistically different between the two waveforms (3.3 ± 1.0 J vs 2.9 ± 1.4 J). However, there also was an inverse correlation between the differences in individual PSRIs and DFTs of the two waveforms (10‐V stimulus: r =−0.62, P < 0.05; 16‐V stimulus: r =−0.75, P < 0.01).

Conclusions: Modulation of defibrillation efficiency by E‐4031 infusion or by changes of the shock waveform was related to the effect of these interventions on PSRI. These results suggest an independent role for the refractoriness of nondepolarized myocardium in the mechanism of defibrillation.
Antiarrhythmic Drug Therapy for Ventricular Arrhythmias: Current Perspectives
Authors: LINK MARK S. , HOMOUD MUNTHER , FOOTE CAROLINE B. , WANG PAUL J. , ESTES N.A. MARK
Published: May 2007

Antiarrhythmic Drug Therapy. Pharmacologic therapy for ventricular arrhythmias has undergone a remarkable change recently. Recognition of the importance of underlying structural heart disease on prognostic implications of ventricular arrhythmias has resulted in the refinement of the clinical classification of these arrhythmias. With refinement of techniques of risk stratification, it is now possible to identify patients with ventricular arrhythmias at high risk for sudden death. Retrospective analyses of prior antiarrhythmic drug trials and new data from prospective randomized trials are now available and can more directly define the risks and benefits of antiarrhythmic therapy. Prevention of sudden death, reduction in total mortality, or improvement in symptoms remain the only benefits of antiarrhythmic drugs. With inclusion of total mortality as the major endpoint for assessment of pharmacologic interventions in high‐risk patients, the potential for excess mortality due to antiarrhythmic agents is now recognized. The pharmacologic diversity of newly released antiarrhythmic agents and others under development has resulted in a re‐evaluation of the traditional classification of these drugs. Multiple ongoing clinical trials will define the risks and benefits of antiarrhythmic therapy and other nonpharmacologic interventions in patients with ventricular arrhythmias.
Strength‐Interval Curves for Cardiac Tissue Predicted Using the Bidomain Model
Authors: ROTH BRADLEY J.
Published: May 2007

Cardiac Strength‐Interval Curves. Introduction: Strength‐interval curves are predicted for unipolar anodal and cathodal stimulation of cardiac muscle.

Methods and Results: Cardiac tissue is represented by the bidomain model, and the active properties of the membrane are described by the Beeler‐Reuter model. Two successive stimuli (S1 and S2) are delivered through a single extracellular electrode. The S2 threshold is determined as a function of the S1‐S2 interval, for anodal and cathodal S2 stimuli with 2‐, 5‐, 10‐, and 20‐msec durations. Each of the resulting cathodal and anodal strength‐interval curves is divided into two parts: one section corresponding to make stimulation (long intervals) and the other section corresponding to break stimulation (short intervals). Generally, the cathodal strength‐interval curves are decreasing functions of interval, except for an anomalous section of the 20‐msec duration cathodal curve in the interval range from 310 to 318 msec. At short intervals, the anodal strength‐interval curve contains a deep dip, which is more prominent for longer S2 durations. The cathodal threshold is less than the anodal threshold for all intervals except those corresponding to the end of the refractory period.

Conclusion: The bidomain model predicts complex anodal and cathodal strength‐interval curves, with the anodal curve containing a dip (supernormal stimulation). These results resemble the experimental observations of Dekker.
Impact of Valvular Calcification on the Diagnostic Accuracy of Transesophageal Echocardiography for the Detection of Congenital Aortic Valve Malformation
Authors: Makkar Akash , Siddiqui Tariq S. , Stoddard Marcus F. , Lewis Robert K. , Dawn Buddhadeb
Published: May 2007

Background: Degeneration of congenital bicuspid or unicuspid aortic valves can progress more rapidly than that of tricuspid valves, and an early diagnosis significantly impacts decision making and outcome. We hypothesized that the extent of valvular calcification would negatively influence the diagnostic accuracy of multiplane transesophageal echocardiography (TEE) for the diagnosis of congenital aortic valve disease. Methods: TEE was performed in 57 patients undergoing aortic valve replacement surgery for aortic stenosis (n = 46), pure regurgitation (n = 9), or significant regurgitation with less than severe aortic stenosis (n = 2). The degree of aortic valve calcification and the number of valve cusps were determined at surgery. Results: Surgical inspection confirmed 14 bicuspid and 43 tricuspid aortic valves. Sensitivity and specificity of TEE for the diagnosis of congenital aortic valve malformation was 93% (13/14) and 91% (39/43) (P = 0.0001), respectively. In patients with no or mild aortic valve calcification (n = 13), sensitivity and specificity of TEE for the diagnosis of congenitally malformed aortic valve was 100% (5/5) and 100% (8/8) (P = 0.001), respectively. In patients with moderate or marked aortic valve calcification (n = 44), sensitivity and specificity of TEE for the diagnosis of congenitally malformed aortic valve was 89% (8/9) and 89% (31/35) (P<0.0001), respectively. In this subgroup of 44 patients, there were four false‐positive and one false‐negative diagnoses due to valvular calcification. Conclusions: Although TEE is highly sensitive and specific for the detection of congenital aortic valve malformations, presence of moderate or marked calcification of the aortic valve may result in false positive and false negative diagnoses.
Strain and Strain Rate Imaging in Evaluating Left Atrial Appendage Function by Transesophageal Echocardiography
Authors: Sevimli Serdar , Gundogdu Fuat , Arslan Sakir , Aksakal Enbiya , Gurlertop Hanefi Yekta , Islamoglu Yahya , Tas Hakan , Acikel Mahmut , Erol Mustafa Kemal , Senocak Huseyin , Karakelleoglu Sule , Atesal Sebahattin , Alp Necip
Published: May 2007

Background:
This study was planned to assess whether strain rate (Sr) and strain (S) echocardiography is a useful method for functional assessment of the left atrial appendage (LAA). Material and Methods: Fifty‐seven consecutive patients underwent a clinically indicated study. LAA late empty velocity (LAAEV) was calculated as a gold standard for left atrial appendage function. Real‐time 2‐dimensional color Doppler myocardial imaging data were recorded from the LAA at a high frame rate. Analysis was performed for LAA longitudinal strain rate and strain from midsegment of lateral wall of LAA. LAA strain determines regional lengthening expressed as a positive value or shortening expressed as a negative value. Peak systolic values were calculated from the extracted curve. Results: Spearman correlation test results showed a statistically significant positive correlation was between the S, Sr variables and LAAEV (LAAEV vs S; r = 0.886, P < 0.001; LAAEV vs Sr: r = 0.897, P < 0.001, respectively). Strain and strain rate values were also significantly lower in patients with spontaneous echocardiographic contrast when compared with those without (strain; 2.42 ± 0.98 vs 13.1 ± 5.9, P < 0.001 and strain rate: 0.97 ± 0.54 vs 3.34 ± 1.15, P < 0.001, respectively). In addition, LAA strain and strain rate values were significantly lower in the patients with LAA thrombus (strain; 2.15 ± 0.96 vs 8.35 ± 6.9, P < 0.001, strain rate; 0.79 ± 0.46 vs 2.30 ± 1.48, P < 0.001, respectively). Conclusion: S and Sr imaging can be considered a robust technique for the assessment of the LAA systolic deformation.
A Case of Primary Cardiac Lymphoma: Analysis of the Role of Echocardiography in Early Diagnosis
Authors: Faganello Giorgio , Belham Mark , Thaman Rajesh , Blundell Julie , Eller Timothy , Wilde Peter
Published: May 2007

Primary Cardiac Lymphoma (PCL) is defined as a non‐Hodgkin's lymphoma involving only the heart and/or pericardium. Diagnosis of this rare disease is particularly difficult due to its nonspecific clinical manifestations. In this review the role of echocardiography in the early diagnosis of PCL is assessed, moreover we report an improvement in the outcome of PCL related to increased availability and utilization of echocardiography.
A Conservative Test for Multiple Comparison Based on Highly Correlated Test Statistics
Authors: Ninomiya Yoshiyuki , Fujisawa Hironori
Published: May 2007

Summary In genetics, we often encounter a large number of highly correlated test statistics. The most famous conservative bound for multiple comparison is Bonferroni's bound, which is suitable when the test statistics are independent but not when the test statistics are highly correlated. This article proposes a new conservative bound that is easily calculated without multiple integration and is a good approximation when the test statistics are highly correlated. The performance of the proposed method is evaluated by simulation and real data analysis.
An Improved Method of Staining the External Organelles of Hypotrichs*
Authors: TURNER HARRY J.
Published: May 2007

A simple, rapid method of staining the external organelles of hypotrichous ciliates is described. Specimens are fixed and stained with Noland's combined phenol‐formaldehyde, gentian violet fixative and stain. The staining solution is displaced with iodized glycerine as soon as the external structures are stained to prevent it from coloring the cell body. Cirri and membranelles are stained jet black in sharp contrast to the clear amber background.
Reorganisation du Type Endomixique chez les Loxodidae et chez les Centrophorella
Authors: FAURE‐FREMIET E.
Published: May 2007

New investigations of the nuclear cycle in the gymnostome ciliate Loxodes rostrum verify the long‐neglected hypothesis proposed by Bütschli that in this multinucleated ciliate the macronuclei never divide. The consequences of this “caryosterose” are compensated for by a process of endomixis, that is, by the transformation of a certain number of the micronuclei, during vegetative multiplication, into new macronuclei.

The nuclear cycle in the gymnostome Centrophorella fistulosa does not show any aspect of nuclear division. Interpretation of this supposes the existence of polyenergid nuclei which fragment, during the interdivisional period, into subnuclei; among these some evolve in the somatic and macronuclear direction, before disappearance by karyolysis; others, corresponding to the micronuclei, grow by endomitosis, and reconstitute the polyploid and polyenergid nuclei. Thus the very particular nuclear cycle of C. fistulosa is believed to exhibit a new aspect in the endomictic process of nuclear reorganization.
On the Cytoplasmic Fibrils of Lophomonas striata
Authors: KUDO R. R.
Published: May 2007

Views on the nature of the cytoplasmic fibrils which occur in Lophomonas striata are considered. It is concluded that on the basis of available information the rods or fibrils should be considered as structures characteristic of this flagellate.
Plagiopyla minuta and Euplotes balteatus, Giliates of the Sea Urchin Strongylocentrotus dröbachiensis
Authors: BEERS C. DALE
Published: May 2007

Of 165 sea urchins (Strongylocentrotus dröbachiensis) examined in the Mt. Desert Island region, 41 harbored the intestinal ciliate Plagiopyla minuta in considerable numbers. Division in this ciliate is clean; i.e. it is not accompanied by the visible elimination of macronuclear material. Long periods (probably several weeks) of vegetative life appear to alternate with brief periods of intense divisional activity in P. minuta. Twenty‐five of these same urchins also contained in their digestive tracts a species of Euplotes which was identified as E. balteatus. This hypotrich was also found commonly in the region as a free‐living organism. Dividing specimens were found regularly in the urchin, and such specimens showed the usual macronuclear reorganization which occurs in Euplotes and its near relatives. The evidence indicates that E. balteatus is a facultative commensal, which is perhaps now in the process of acquiring the endozoic habit.
Immunology and Serology of Some Parasitic Protozoan Flagellates. II. The Hemoflagellate Protozoa, Leishmania donovani and Trypanosoma cruzi*
Authors: MENOLASINO NICHOLAS J. , HARTMAN ERNEST
Published: May 2007

Antigens consisting of simple fractions of T. cruzi and L. donovani produced high titer antisera in the rabbit after a short immunization series. The antisera resulting from these immunizations showed several types of serologic reactions with the living antigens when the dark‐field serial dilution technique, devised for these experiments, was employed.
The Oxidative Metabolism of a Cryptomonad Flagellate, Chilomonas paramecium*
Authors: HOLZ GEORGE G.
Published: May 2007

Tests based on respirometric and population growth methods for the analysis of oxidizable substrates for Chilomonas paramecium revealed that only those substances tested which are intermediates in terminal cyclic respiratory mechanisms (pyruvate, lactate, acetate, α‐ketoglutarate, succinate, fumarate, L‐malate, oxalacetate, but not citrate, cis‐aconitate or DL‐isocitrate) were attacked. These organic acids, and the fatty acids and alcohols earlier known to be used, n‐butyric, n‐caproic and n‐caprylic acids, ethyl, n‐butyl and n‐hexyl alcohols, were the only carbon compounds oxidized by C. paramecium under the test conditions employed.

Utilization of acid substrates was found to be pH‐dependent. Reproductive and respiratory rates were related to the pKa values of the compounds. Oxidation of acetate, lactate, and pyruvate, however, was observed at pH values where their molecular form was present in exceedingly small amounts.

Naturally‐occurring α‐amino acids, amines, glycolysis intermediates (3‐phosphoglyceric acid, glucose‐1‐phosphate, hexose diphosphate) and degraded intermediates of glycolysis (glyceric acid, glycerol, dihydroxyacetone, glucose), two‐carbon compounds more oxidized than acetic acid (oxalic, glycolic, glyoxylic acids, glyoxal, ethylene glycol), and formic, tartaric, malonic, and glutaric acids, were not used.

Respiration in the presence of single members of the group of oxidizable substrates was sensitive to malonate and fluoroacetate. Malonate inhibition of succinate oxidation could be reversed by an increase in succinate concentration, but the relationship was not competitive; possibly because of permeability differences between the substrate and inhibitor. Fluoroacetate inhibition was accompanied by the accumulation of citric acid.

The experiments on substrate oxidation, and the effects of inhibitors on the respiratory metabolism of the flagellate, are considered to provide evidence for the operation of the Krebs tricarboxylic acid cycle as a terminal respiratory mechanism in C. paramecium.
The Literature on Tetrahymena: Its History, Growth, and Recent Trends*
Authors: CORLISS JOHN O.
Published: May 2007

The literature involving the genus Tetrahymena has become so voluminous in recent years that some consolidation of it appears advisable. Through 1953 well over 500 papers, scattered through more than 100 scientific journals, have been devoted in whole or in part to studies in which species and strains of this genus, under a variety of names, have been employed as one of the experimental animals. Nearly half of these works are cited directly in the present paper. The major areas of research in which these ciliates have been used to advantage include physiology and biochemistry, containing nearly 60% of all the papers, cytology and taxonomy, and three smaller fields arbitrarily designated as cytogenetics, morphogenesis, and parasitism.

Tetrahymena's sustained popularity as an object of research may be considered as due primarily to its ability to thrive axenically in a chemically defined nutrient medium and secondarily to such factors as its ubiquity in nature, its ready adaptability to a variety of ecological situations (including endoparasitism), its possession of a relatively primitive and fundamental type of buccal ciliature of considerable phylogenetic significance, and its exhibition of the sexual phenomena of conjugation and autogamy.
A Method for Obtaining Amacronucleated Animals in Paramecium aurelia.*
Authors: MARGOLIN PAUL
Published: May 2007

Amacronucleated single animals of Paramecium aurelia are produced by a three‐step procedure. The three steps are: 1) the formation of homopolar double animals, 2) the reduction in number of macronuclei from two to one and the maintenance of this unimacronucleated condition, and 3) the occurrence of clefts in these unimacronucleated double animals. The amacronu‐cleated single animals are produced from the unimacronucleated, partially separated, homopolar double animals either by fission or by the complete separation of the two components of the double animals. The method described may apply in principle to many other ciliates.
La Position Systematique du Genre Balantidium
Authors: FAURÉ‐FREMIET E.
Published: May 2007

SUMMARY. Since the work of Stein the systematic position of the genus Balantidium in the spirotrichous order Heterotrichida generally has been accepted without question. Reported here are some new observations, of taxonomic significance, on the infraciliature and on the mechanisms of stomatogenesis in Balantidium elongatum and B. entozoon. The results obtained verify and complete earlier cytological observations made by a number of authors; consideration of the present findings, however, suggests that Balantidium is a holotrichous ciliate of the type “prostomien” and that the family Balantidiidae logically belongs alongside that of the Plagiopylidae, in the holotrichous order Trichostomida.
Tetrahymena from Mexico, Panama, and Colombia, with Special Reference to Sexuality.*
Authors: ELLIOTT ALFRED M. , HAYES ROBERT E.
Published: May 2007

SUMMARY. Twenty‐two % of the fresh water samples taken from Mexico, Colombia, Panama and the Canal Zone contained T. pyriformis. The habitats included springs, roadside ditches, creeks, rivers, ponds, and lakes. They ranged in elevation from sea level to 10,000 feet and in temperature from approximately 8° to 35°C. There was no correlation between temperature of habitat and resistance to high temperatures. Thirty‐eight % of the clones isolated contained micronuclei and all but three of these were assigned to variety and mating type. The clones from Mexico all belong to variety 2, mating type V. Those from Colombia belong to mating type IV, variety 9, a new variety. Five mating types in variety 9 and nine in variety 2 were found in Panama and the Canal Zone. All clones grew in the chemically defined medium that supports the growth of strain E.
Saprophilus muscorum Kahl, a Tetrahymenal Ciliate*
Authors: Stout J. D.
Published: May 2007

SUMMARY. Saprophilus muscorum Kahl, 1931 is an edaphic species which has been identified in cultures of soil and forest litter. This ciliate has the buccal ciliary apparatus of the family Tetrahymenidae Corliss. There is only one post‐oral meridian and 15 bipolar meridians, 8 of which meet ventrally at the pre‐oral suture. The cilia are long and sparse and there is a prominent longer caudal cilium. Trichocysts are present. Resting or resistant cysts are formed readily.
Excystment of Frontonia depressa (Stokes) Penard*
Authors: Stout J. D.
Published: May 2007

SUMMARY. Frontonia depressa (Stokes) Penard is an edaphic species characterized by formation of cysts. There is no dedifferentiation of the ciliate when encysted, and all organelles, except the body cilia and buccal apparatus, are clearly visible. Excystment is dependent upon the building up of hydrostatic pressure by the contractile vacuole. Activation is not always followed by excystment, which takes some hours.
A New Eugregarine of Locusts, Gregarina garnhami n.sp., parasitic in Schistocerca gregaria Forsk.
Authors: CANNING ELIZABETH U.
Published: May 2007

SUMMARY. The structure and life history of a new species of eugregarine, Gregarina garnhami n.sp., is described from the intestinal caeca and mid‐gut of Schistocerca gregaria Forsk. The parasite destroys considerable areas of the caecal epithelium and in cases of heavy infection, the masses of parasites present in the mid‐gut result in the formation of localized barriers between the gut wall and the food material in the lumen. The cephalont and sporont stages of gregarines from Locusta migratoria migratorioides R. & F. and Anacrydium aegyptium Linn. are shown to be similar to those from Schistocerca gregaria and are believed to belong to the same species.
The Metabolism of Trichomonas vaginalis: The Glycolytic Pathway*
Authors: WIRTSCHAFTER SAMUEL , JAHN THEODORE L.
Published: May 2007

SUMMARY. Three enzymes of the glycolytic pathway, hitherto not identified in Trichomonas vaginalis, have been studied: phosphoglucomutasse, α‐glycerophosphate dehydrogenase, and lactic dehydrogenase.

The identification of seven phosphorylated glycolytic intermediates is reported.

The operation of glycolysis in T. vaginalis is postulated from enzymatic as well as chemical studies.
The Metabolism of Trichomonas vaginalis: The Oxidative Pathway*†
Authors: WIRTSCHAFTER SAMUEL , SALTMAN PAUL , JAHN THEODORE L.
Published: May 2007

SUMMARY. Washed intact cell preparations of T. vaginalis oxidize pyruvate and malate. They are unable to utilize other intermediates of the Krebs cycle. Homogenates of these cells show the same pattern of enzymatic dehydrogenase activity toward the Krebs cycle organic acids. Attempts to inhibit pyruvate oxidation with such Krebs cycle blocking agents as malonate, arsenite, parapyruvate, and fluoroacetate were unsuccessful.

Isotopic tracer studies with 2‐C14 pyruvate showed that although several, as yet unidentified, compounds incorporated activity during the course of pyruvate metabolism, none of these labeled compounds corresponded to any of the Krebs cycle intermediates.

It is concluded that the Krebs cycle is not the pathway for the oxidation of pyruvate in T. vaginalis.
A Study of Changes Occurring in Plasmodium lophurae after Three Years of Continuous Existence in Mice
Authors: MCGHEE R. BARCLAY
Published: May 2007

SUMMARY. The characteristics of Plasmodium lophurae infections in mice have been studied for a period of 3 years. The average height of parasitemias increased steadily for several months then leveled off with but minor changes for the remainder of the time. Gametocytes were found during the ninth month after the passages were begun. Comparison of the strain after 3 years in mice with the same species of parasite maintained constantly in chick embryos indicated that the sojourn in the mouse had temporarily disturbed the mean numbers of merozoites produced.
Adaptation by Tetrahymena pyriformis to Potassium Cyanide II. Adaptation Against Respiratory Inhibition*
Authors: MCCASHLAND B. W.
Published: May 2007

SUMMARY. Cells from a clonal culture of Tetrahymena pyriformis W were cultured in the presence of 10‐4 M KCN for a prolonged time until they became “adapted” to cyanide. The effect of 10‐3 M KCN upon respiration in the “adapted” cells was compared with the effect upon “normal” cells of the same clone grown in the absence of cyanide. The direct method of Warburg was employed.

Adapted cells are more resistant against respiratory inhibition than are normal cells. Resistance is due both to a factor or factors retained within the cell and the extracellular factor(s) released into the medium by the adapted cells during their growth. The intracellular factor is acid labile, and apparently may be developed within a short time. The extracellular factor is heat labile and may cause normal cells to be more resistant against respiratory inhibition by KCN.

Resistance to respiratory inhibition is lost if adapted cells are cultured in the absence of KCN. It is proposed that changes involved in gain or loss of cyanide resistance are due to physiological adaptation and not to the usual genetic influences.
Studies on Dried Cysts of Tillina magna*
Authors: Bridgman Anna Josephine
Published: May 2007

SUMMARY. Tillina magna is a large holotrichous ciliate, of the family Colpodidae, which normally forms resting cysts. These cysts, when formed in their natural environment, withstand drying. Active animals have been excysted from dirt collected more than 10 years ago. However, until recently, laboratory work on these, as well as on most other ciliate cysts, has been done on wet cysts. A method is described for producing viable dry cysts under laboratory conditions. It consists essentially of inducing the tillinas to encyst on prepared sections of grass stems. In this way dry cysts have been formed which are viable up to 4 months. These cysts, when first formed, can be activated simply by the addition of water. Cysts which are no longer responsive to water alone may sometimes be induced to excyst by the addition of lettuce infusion. Cysts withstand extremes of temperature from ‐5°C. to 45°C. These facts have some bearing on the question of the factor or factors causing excystment.
Induced Resistance to Sulfonamides in Chilomonas paramecium
Authors: Hall R. P.
Published: May 2007

SUMMARY. Strains of Chilomonas paramecium differing in degree of resistance to sulfanilamide have been established through acclimatization to this sulfonamide at 50, 100 and 200 mg. %. Resistant strains differ from the normal stock in their enhanced sensitivity to p‐aminobenzoic acid. In the normal stock, sulfanilamide inhibition is reversed at an SA/PABA ratio of 10,000 but not at 20,000; in the least resistant strain, at a ratio of 400,000 but not at 800,000. In resistant strains inhibition is reversed by folk acid, methionine, adenine, cytosine and thymine; in the normal stock, none of these metabolites produces reversal. In high concentrations of PABA (10–20 mg. %) growth of the normal stock is only retarded, whereas the strain least resistant to sulfanilamide fails to recover from exposure to 20 mg. % PABA. The strain most resistant to sulfanilamide is most susceptible to PABA in high concentrations. The data suggest that resistance to sulfanilamide in C. paramecium may depend mainly upon an accelerated synthesis of PABA.
Chromosome Studies in the Genus Plasmodium
Authors: Wolcott Gordon B.
Published: May 2007

SUMMARY. A study has been made of the number and morphology of the chromosomes of five species of malarial parasites as seen in living material with phase contrast microscopy. Plasmodium knowlesi, of monkeys, is essentially similar to other primate malarial parasites previously studied, having two chromosomes of unequal length. P. lophurae, from ducks, P. relictum from pigeons and sparrows, and P. floridense from a lizard all have two small chromosomes of equal size. These facts, with ether data, indicate that the genus may consist of two species complexes. P. berghei, studied in white mice and rats, has a karyotype similar to the avian and saurian malarial parasites. The suggestion is made that P. berghei, on a basis of chromosome pattern and other characteristics, is probably more closely related to the avian and saurian species of Plasmodium than to other mammalian species.
New Species of Eimeria from Arizona Rodents
Authors: Levine Norman D. , Ivens Virginia , Kruidenier Francis J.
Published: May 2007

SUMMARY. In a survey of 52 rodents of 25 species from Grand Canyon National Park, Arizona and its vicinity, the following species of Eimeria are described: E. tamiasciuri n. sp. from the red or spruce squirrel, Tamiasciurus hudsonicus; E. lateralis n. sp. and Eimeria sp. from the mantled ground squirrel, Citellus lateralis; E. eutamiae n. sp. from the cliff chipmunk, Eutamias dorsalis; E. thomomysis n. sp. from the pocket gopher, Thomomys bottae; E. perognathi n. sp. from the rock pocket mouse, Perognathus intermedius; E. albigulae n. sp. from the white‐throated woodrat, Neotoma albigula; E. operculata n. sp. from Stephens' woodrat, Neotoma stephensi; E. peromysci n. sp. and E. arizonensis n. sp. from the piñon mouse, Peromyscus truei; E. eremici n. sp. from the cactus mouse, Peromyscus eremicus; and E. onychomysis n. sp. from the northern grasshopper mouse, Onychomys leucogaster.
Concrétions Minérales Intracytoplasmiques chez les Ciliés
Authors: Fauré‐Fremiet E. , Gauchery M.
Published: May 2007

SUMMARY. Various species of ciliates are characterized by the formation and accumulation in the cytoplasm of mineral concretions which are refringent, isotropic or anisotropic. These cytoplasmic inclusions most often are composed of calcium carbonate; in several species, however, their nature remains partially or even totally undetermined. The isotropic calcium‐containing concretions often exhibit a definite shape; the calcium carbonate in this case appears to be bound to an organic substrate. The physiological role of the calcic concretions is not known; their characteristic presence in a given species is not necessarily related to ecological conditions. In a few species the calcification is localized in definite structures: spicules, skeletal plates, or otoliths of organelles supposedly sensory in nature.