bluuebunny/crossref_metadata_2025 huggingface dataset:
Origin of Electrical Activation Within the Right Atrial and Left Ventricular Walls:
Authors: KROLL MAJA , KRIEBEL THOMAS , WINDHAGEN‐MAHNERT BRITTA , FRANZBACH BIRGIT , JUX CHRISTIAN , ZUTZ MARTINA , TEBBENJOHANNS JÜRGEN , PAUL THOMAS
Published: October 2003

Clinical data using the noncontact mapping system (Ensite 3000) suggest that characteristics of the reconstructed unipolar electrograms may predict the origin of electrical activation within the atrial and ventricular walls (endocardial vs myocardial vs epicardial origin). Experimental data are lacking. In ten open‐chest pigs (mean body weight 62 kg) cardiac pacing was performed at a cycle length of 600 ms with a pulse width of 2 ms and twice diastolic threshold from the endo‐, the myo‐, and the epicardium, respectively. Pacing was undertaken at three right atrial and three left ventricular sites, and cardiac activation was recorded with the Ensite system. Reconstructed unipolar electrograms at the location of earliest endocardial activation assessed by color coded isopotential maps were analyzed systematically for differences in morphology. The positive predictive value of atrial electrograms exhibiting an initial R wave during pacing for a subendocardial origin (i.e., myocardial or epicardial) was 0.96. The negative predictive value was 0.48. Electrograms generated during myocardial pacing exhibited increased maximal negative voltage and maximal dV/dt (−3 ± 1.8 mV, −798 ± 860 mV/ms, respectively) than the electrograms obtained during endocardial (−2 ± 1 mV, −377 ± 251 mV/ms, respectively) and epicardial pacing (−2.1 ± 0.7 mV, −440 ± 401 mV/ms, respectively, P < 0.01 for both parameters). During pacing at the left ventricular wall, occurrence of an initial R wave did not differ significantly between electrograms reconstructed during endocardial and subendocardial pacing. All other characteristics of the unipolar ventricular electrograms analyzed, except latency, did not differ significantly when compared to stimulation depth. Morphological characteristics of unipolar electrograms generated by the noncontact mapping system during pacing of the atrium allowed for discrimination of an endocardial versus a subendocardial origin of activation. At the ventricular level, characteristics of unipolar electrograms did not predict the origin of cardiac activation in this experimental setting. (PACE 2003; 26:1970–1978)
Effects of Simultaneous Insertion of 66 Plunge Needle Electrodes on Myocardial Activation, Function, and Structure
Authors: KOVOOR PRAMESH , CAMPBELL CRAIG , WALLACE ELISABETH , BYTH KAREN , DEWSNAP BARBARA , EIPPER VICKI , UTHER JOHN , ROSS DAVID
Published: October 2003

Transmural recordings using plunge needle electrodes are useful in mapping ventricular tachyarrhythmia, but they interfere with activation sequences or damage the myocardium. This study evaluated the effects of insertion of 66 transmural needles on myocardial activation, structure, and function. Epicardial maps were performed at thoracotomy using a 40‐electrode plaque in five mongrel dogs. Sixty‐six transmural plunge needles were introduced into the anterior aspect of the septum and left ventricle. Transmural maps of unipolar electrograms were recorded every 15 minutes via 124 electrodes over a 2‐hour period. Epicardial maps were repeated after the needles were removed. All recordings were performed during sinus rhythm and ventricular pacing at 300‐ and 200‐ms cycle lengths. Gated heart pool studies were performed preoperatively and 2 weeks after thoracotomy. Programmed ventricular stimulation was performed 2 weeks after thoracotomy. In total, 15,996 electrograms were analyzed. Maximum negative dV/dt of each electrogram and the activation time at each electrode did not change significantly over the 2 hours of needle insertion. After removal of the needles, epicardial maps were unchanged compared to before needle insertion. Mean left ventricular ejection fraction 2 weeks after needle insertion was 59% versus 58% before needle insertion (P = 0.9). No dogs had inducible ventricular tachycardia. Histology showed contraction bands of 0.8‐mm diameter adjacent to the needle tracks but no scarring. Insertion of 66 closely spaced plunge needles did not distort epicardial or transmural maps. Multiple needles did not result in myocardial scarring, left ventricular dysfunction, or predispose to ventricular tachycardia. (PACE 2003; 26:1979–1985)
Assessment of Radiofrequency Ablation Effect From Unipolar Pacing Threshold
Authors: DELACRETAZ ETIENNE , SOEJIMA KYOKO , BRUNCKHORST CORINNA B. , MAISEL WILLIAM H. , FRIEDMAN PETER L. , STEVENSON WILLIAM G.
Published: October 2003

Methods for determining if an ablation lesion has been created by RF current application are limited, but needed. This study sought to determine if a change in pacing threshold at the ablation site might be used to assess creation of an ablation lesion. Peak‐to‐peak amplitude of the bipolar electrogram (EGM) and the unipolar pacing threshold were determined before and after creation of RF lesions using irrigated tip (63 lesions in 11 patients) or conventional ablation catheters (33 lesions in 9 patients) in infarct scars for ablation of ventricular tachycardia. The threshold was measured during continuous pacing at a cycle length of 600 ms by a decrementing output current at a pulse width of 2 ms. The unipolar pacing threshold increased by
254 ± 248%
(from
5.7 ± 3.5
to
15.1 ± 6.7 mA, P < 0.001
) after irrigated tip ablation and by
155 ± 144%
(from
5.9 ± 3.4
to
12.3 ± 5.7 mA, P < 0.001
) after conventional ablation (
P < 0.05
for irrigated tip vs conventional). EGM amplitude decreased by
17 ± 27%
(from
0.39 ± 0.32
to
0.30 ± 0.21 mV
) after irrigated tip ablation and by
16 ± 24%
(from
0.48 ± 0.27
to
0.41 ± 0.20 mV
) after conventional ablation (irrigated tip vs conventional, P = NS). There was no correlation between the change in bipolar EGM amplitude and the pacing threshold. An increase in unipolar pacing threshold is a marker of lesion creation. In regions of infarction, the relative change in threshold produced by ablation is substantially larger than the change in bipolar electrogram amplitude. The greater increase in pacing threshold after irrigated tip ablation compared to conventional ablation suggests that the magnitude of change reflects lesion size. (PACE 2003; 26:1993–1996)
Pacemaker Ventricular Block
Authors: KISTLER PETER M. , MOND HARRY G. , VOHRA JITENDRA K.
Published: October 2003

Pacemaker ventricular block is a rare and poorly recognized electrocardiographic abnormality usually identified in terminally ill pacemaker patients. Because the patient is frequently moribund and the phenomenon transient, it is probably overlooked and not well documented. It is characterized by an altered temporal relationship between the pacemaker stimulus artifact and the subsequent paced QRS. The most common presentation is a delay or latency between the stimulus artifact and the QRS called first‐degree pacemaker ventricular block. This can then deteriorate to periodic episodes of failure to capture the myocardium referred to as second‐degree pacemaker ventricular block that may manifest as a classical Wenckebach or higher levels of block. Any further deterioration results in a third‐degree pacemaker ventricular block, which is failure to capture the ventricle and asystole. This article describes electrocardiographic examples of this phenomenon. (PACE 2003; 26:1997–1999)
Clinical Efficacy of a Wearable Defibrillator in Acutely Terminating Episodes of Ventricular Fibrillation Using Biphasic Shocks
Authors: REEK SVEN , GELLER J. CHRISTOPH , MELTENDORF ULF , WOLLBRUECK ANKE , SZYMKIEWICZ STEVEN J. , KLEIN HELMUT U.
Published: October 2003

The Wearable Cardioverter Defibrillator (WCD) automatically detects and treats ventricular tachyarrhythmias without the need for assistance from a bystander, while at the same time allowing the patient to ambulate freely. It represents an alternative to emergency medical services for outpatient populations with a temporary risk of sudden cardiac death. While the original devices used a monophasic truncated exponential waveform for cardioversion/defibrillation shocks, a new, biphasic shock was developed for the next device generation. In 12 patients undergoing electrophysiological testing for ventricular tachyarrhythmias, termination of electrically induced ventricular fibrillation (VF) was attempted via the WCD. In 22 episodes, induced VF was promptly terminated by the first 70 J (n = 12) or 100 J (n = 10) biphasic shocks. Time between arrhythmia initiation and shock delivery was 22 ± 6 seconds (70 J) and 21 ± 6 seconds (100 J) (P = NS). The measured transthoracic impedance was 71 ± 5 Ω (64–79 Ω) for the 70 J shock and 64 ± 8 Ω (47–72 Ω) for the 100 J shock. The present study demonstrates that a single low energy biphasic shock delivered by the WCD, reliably terminates electrically induced VF (100% of episodes). The results of this study suggest that there is an acceptable safety margin to the maximum output of the device (150 J). Despite our promising data, we recommend that programming all shocks for maximum energy output should be done when using the WCD in ambulatory patients. (PACE 2003; 26:2016–2022)
Optimal Atrioventricular Intervals During Dual Chamber Pacing in Patients with a Univentricular Heart:
Authors: NOTHROFF JOERG , BUCHHORN REINER , RUSCHEWSKI WOLFGANG
Published: October 2003

The benefit of a dual chamber pacemaker and the atrial and ventricular synchronization in patients with two ventricles is widely accepted. The purpose of this study was to choose the optimal AV interval in patients with congenital heart disease after definitive palliation of univentricular hearts. Therefore, different AV intervals were programmed and hemodynamic aspects were examined by Doppler echocardiography. The interval found was different from normal heart morphology and two ventricular hemodynamics. (PACE 2003; 26:2048–2049)
Comparative biology of oogenesis in nemertean worms
Authors: Stricker Stephen A. , Smythe Toni L. , Miller Leonard , Norenburg Jon L.
Published: October 2003

Stricker, S. A., Smythe, T. L., Miller, L. and Norenburg, J. L. 2001. Comparative biology of oogenesis in nemertean worms. —Acta Zoologica (Stockholm) 82: 213–230

In order to supplement previous analyses of oogenesis in nemertean worms, this study uses light and electron microscopy to compare the ovaries and oocytes in 16 species of nemerteans that represent various taxa within the phylum. Nemertean ovaries comprise serially repeated sacs with an ovarian wall that characteristically includes myofilament‐containing cells interspersed among the germinal epithelium. Each oocyte can attach to the germinal epithelium by a vegetally situated stalk and resides in the ovarian lumen without being surrounded by follicle cells. In the ovary, oocytes arrest at prophase I of meiosis and contain a hypertrophied nucleus (‘germinal vesicle’) that often possesses multiple nucleoli. Intraovarian growth apparently involves an autosynthetic mode of yolk formation in most nemerteans and generates oocytes that measure ~60 µm to 1 mm. When fully developed, oocytes can be discharged through a short gonoduct and are either spawned freely or deposited within egg cases. In most species, oocytes released from the ovary possess extracellular coats and resume maturation by undergoing germinal vesicle breakdown (GVBD). Such post‐GVBD specimens also form a punctate endoplasmic reticulum that may facilitate fertilization and development.
Morphology and organization of muscle fibres in the thoracic coxal muscle receptor organ and the associated promotor muscle, in a crayfish, Cherax destructor, and mud crab, Scylla serrata
Authors: Parkinson Ann L. , Bakker Anthony J. , Head Stewart I.
Published: October 2003

Using confocal laser scanning and conventional light microscopy, the morphology and organization of the muscle fibres in a proprioceptor, the thoracic coxal muscle receptor organ (TCMRO), and the associated ‘extrafusal’ promotor muscle were investigated in two species of decapod crustacea, the crayfish Cherax destructor and the mud crab Scylla serrata. The diameter of the TCMROs was shown to increase distally, with an increase up to 350% recorded for the crayfish. The tapered shape of the crayfish TCMRO was demonstrated to amplify movements mechanically at the transducer region where the afferent nerves attach. Serial sectioning of the TCMROs, showed that the fibre number increased in the proximal to distal direction from 14 to 30 fibres in the crayfish and from 7 to 20 in the crab. Optical sectioning with the laser scanning confocal microscope revealed that the increase in fibre numbers was the result of muscle fibres branching in the distal third section of the TCMRO. The percentage of muscle tissue in the cross‐sectional area in the TCMRO was found to be only 35.2% and 64.6% in the crayfish and crab, respectively. Longitudinal sectioning using laser scanning confocal microscopy revealed the average sarcomere length of the TCMRO muscle fibres of both species to be in the intermediate range for crustacean muscle fibres (4.1 ± 0.1 µm and 4.55 ± 0.34 µm for the crayfish and crab) compared with the long sarcomere muscle fibres in the associated promotor muscles (7.87 ± 0.2 and 10.6 ± 0.6 µm). The distinct morphology of the TCMRO muscle fibres – smaller diameter, intermediate sarcomere length and branching of fibres compared to the larger, long sarcomere promotor fibre muscle fibres – suggest that the TCMRO muscle fibres are specialized in their role of proprioception.
Haloperidol impairs auditory filial imprinting and modulates monoaminergic neurotransmission in an imprinting‐relevant forebrain area of the domestic chick
Authors: Gruss M. , Bock J. , Braun K.
Published: October 2003

In vivo
microdialysis and behavioural studies in the domestic chick have shown that glutamatergic as well as monoaminergic neurotransmission in the medio‐rostral neostriatum/hyperstriatum ventrale (MNH) is altered after auditory filial imprinting. In the present study, using pharmaco‐behavioural and
in vivo
microdialysis approaches, the role of dopaminergic neurotransmission in this juvenile learning event was further evaluated. The results revealed that: (i) the systemic application of the potent dopamine receptor antagonist haloperidol (7.5 mg/kg) strongly impairs auditory filial imprinting; (ii) systemic haloperidol induces a tetrodotoxin‐sensitive increase of extracellular levels of the dopamine metabolite, homovanillic acid, in the MNH, whereas the levels of glutamate, taurine and the serotonin metabolite, 5‐hydroxyindole‐3‐acetic acid, remain unchanged; (iii) haloperidol (0.01, 0.1, 1 m
m
) infused locally into the MNH increases glutamate, taurine and 5‐ hydroxyindole‐3‐acetic acid levels in a dose‐dependent manner, whereas homovanillic acid levels remain unchanged; (iv) systemic haloperidol infusion reinforces the
N
‐methyl‐
d ‐aspartate receptor‐mediated inhibitory modulation of the dopaminergic neurotransmission within the MNH. These results indicate that the modulation of dopaminergic function and its interaction with other neurotransmitter systems in a higher associative forebrain region of the juvenile avian brain displays similar neurochemical characteristics as the adult mammalian prefrontal cortex. Furthermore, we were able to show that the pharmacological manipulation of monoaminergic regulatory mechanisms interferes with learning and memory formation, events which in a similar fashion might occur in young or adult mammals.
Feeding area specialization of chick‐rearing Adélie Penguins Pygoscelis adeliae in a fast sea‐ice area
Authors: Watanuki Yutaka , Takahashi Akinori , Sato Katsufumi
Published: October 2003

Individual feeding area specialization has been reported for several seabird species. Researchers suspect that this behaviour results in feeding and/or reproductive advantages. Adélie Penguins Pygoscelis adeliae feed in small predictable open waters in a fast sea‐ice area near Syowa Station, Antarctica. Their feeding sites were determined by radiotracking both members of 20 pairs rearing chicks. Twenty‐five birds repeatedly fed in distinct areas more frequently than expected by chance, while the remaining 15 birds had no significant feeding area specialization. Birds seemed to feed at sites that were closer to their most recent feeding sites than they were to earlier feeding sites. Variation in specialized area, degree of feeding area fidelity and distance to feeding sites had no significant effect on the number of feeds that a bird brought to chicks per day. Neither did the estimated mass of feeds brought per day per pair depend on feeding area specialization.
Habitat use, foraging ecology and diet of Turtle Doves Streptopelia turtur in Britain
Authors: Browne Stephen J. , Aebischer Nicholas J.
Published: October 2003

Since 1968, Turtle Doves Streptopelia turtur in Britain have declined in number by 70% and in breeding range by at least 25%. This study was undertaken during the 1998–2000 breeding seasons at two sites in East Anglia to examine habitat use and foraging ecology. Home ranges of radiotagged Turtle Doves were 0.3–1130 ha in size and contained more woodland than expected from availability. Radiotagged birds undertook foraging trips of up to 10 km. Turtle Doves were recorded feeding primarily at ‘man‐made’ sites (i.e. spilt grain, animal feed and grain stores) and were only infrequently recorded feeding at ‘natural’ sites. Diet analysis showed that wheat and rape seed averaged 61% of the seeds eaten by Turtle Doves. This contrasts with a study undertaken in Britain in the 1960s, when the seeds of wild plants (weeds) constituted over 90% of those eaten, with wheat and rape seeds making up only 5%. The current arrangements for set‐aside and agri‐environmental schemes provide a framework for the establishment and maintenance of weed‐rich areas on farmland as a source of wild food.
Reproductive ecology of Tibetan Eared Pheasant Crossoptilon harmani in scrub environment, with special reference to the effect of food
Authors: Lu Xin , Zheng Guang‐Mei
Published: October 2003

We studied the nesting ecology of two groups of the endangered Tibetan Eared Pheasants Crossoptilon harmani in scrub environments near Lhasa, Tibet, during 1996 and 1999–2001. One group received artificial food from a nunnery prior to incubation whereas the other fed on natural food. This difference in the birds’ nutritional history allowed us to assess the effects of food on reproduction. Laying occurred between mid‐April and early June, with a peak at the end of April or early May. Eggs were laid around noon. Adult females produced one clutch per year. Clutch size averaged 7.4 eggs (4–11). Incubation lasted 24–25 days. We observed a higher nesting success (67.7%) than reported for other eared pheasants. Provisioning had no significant effect on the timing of clutch initiation or nesting success, and a weak effect on egg size and clutch size (explaining 8.2% and 9.1% of the observed variation, respectively). These results were attributed to the observation that the unprovisioned birds had not experienced local food shortage before laying, despite spending more time feeding and less time resting than the provisioned birds. Nest‐site selection by the pheasants was non‐random with respect to environmental variables. Rock‐cavities with an entrance averaging 0.32 m2 in size and not deeper than 1.5 m were greatly preferred as nest‐sites. The birds were also more likely to place their nests in denser high‐scrub and closer to streams. In the study area, the low availability of both cliff habitats and high‐scrub patches suggested a limitation of sites suitable for nesting, which could be reflected in the between‐year re‐use of nest‐sites (8.9%) and intraspecific nest parasitism (3.8%). Despite the apparent preference for certain nest‐site variables, we found no effect of these on clutch fate, suggesting that the risk of nest predation was random.
New constraints on metamorphism in the Rauer Group, Prydz Bay, east Antarctica
Authors: Kelsey D. E. , White R. W. , Powell R. , Wilson C. J. L. , Quinn C. D.
Published: October 2003

Abstract Granulite facies metapelites of the Mather and Filla Paragneisses within the Rauer Group, east Antarctica, possess markedly different compositions. The metamorphic evolution of the two metapelite types has been interpreted as temporally distinct, with the Rauer Group preserving at least two distinct granulite facies tectonothermal episodes. Calculated P–T pseudosections and orthopyroxene Al content indicate the revised maximum‐preserved P–T conditions within the Mather Paragneiss to lie in the vicinity of 950–975 °C and 10–10.6 kbar, less extreme than previous estimates. The range of possible P–T paths for the Mather Paragneiss consistent with mineral textural relationships and pseudosections contoured for mineral proportion are significantly shallower (dP/dT) than previous estimates. A near‐isothermal decompression P–T path, and extreme peak metamorphic conditions, are not necessary to explain the development of preserved mineral reaction textures. The Filla Paragneiss contains pelitic assemblages less amenable to rigorous quantitative analysis. Nevertheless, possibilities for the shared or otherwise metamorphic evolution of the Mather and Filla Paragneisses may be postulated on the basis of calculated pseudosections in the context of existing geochronology for the Rauer Group and preserved microstructures. A shared evolution, most likely during Pan‐African granulite facies metamorphism, is plausible and consistent with mineral assemblage development, geochronology and microstructures. A revised interpretation of the Rauer Group's preserved metamorphic evolution may warrant the revision of existing tectonic models, applicable also to the remainder of Prydz Bay. More generally, the employed approach may incite a revision of peak P–T and P–T paths in other granulite facies terranes.
Geothermobarometry, P–T paths and metamorphic field gradients of high‐pressure rocks from the Adula Nappe, Central Alps
Authors: Dale J. , Holland T. J. B.
Published: October 2003

Metabasic rocks from the Adula Nappe in the Central Alps record a regional high‐pressure metamorphic event during the Eocene, and display a regional variation in high‐pressure mineral assemblages from barroisite, or glaucophane, bearing garnet amphibolites in the north to kyanite eclogites in the central part of the nappe. High‐pressure rocks from all parts of the nappe show the same metamorphic evolution of assemblages consistent with prograde blueschist, high‐pressure amphibolite or eclogite facies conditions followed by peak‐pressure eclogite facies conditions and decompression to the greenschist or amphibolite facies. Average PT calculations (using thermocalc) quantitatively establish nested, clockwise P–T paths for different parts of the Adula Nappe that are displaced to higher pressure and temperature from north to south. Metamorphic conditions at peak pressure increase from about 17 kbar, 640 °C in the north to 22 kbar, 750 °C in the centre and 25 kbar, 750 °C in the south. The northern and central Adula Nappe behaved as a coherent tectonic unit at peak pressures and during decompression, and thermobarometric results are interpreted in terms of a metamorphic field gradient of 9.6 ± 2.0 °C km−1 and 0.20 ± 0.05 kbar km−1. These results constrain the peak‐pressure position and orientation of the nappe to a depth of 55–75 km, dipping at an angle of approximately 45° towards the south. Results from the southern Adula Nappe are not consistent with the metamorphic field gradient determined for the northern and central parts, which suggests that the southern Adula Nappe may have been separated from central and northern parts at peak pressure.
Blood Product Use During Routine Open Heart Surgery: The Impact of the Centrifugal Pump
Authors: Klein Michael , Mahoney Chris Brown , Probst Chris , Schulte Hagen D. , Gams Emmeran
Published: October 2003

Abstract: A prospective randomized study was done including 1,000 patients undergoing routine open heart surgery. Patients were randomly assigned to either a roller pump or a BioMedicus centrifugal pump with identical extracorporeal circuits.There were no significant differences between study groups. Actual blood products transfused and predicted transfusion requirements (using Cardiac RiskMaster) were examined as was chest tube drainage (CTD). The predicted tranfusion requirement was 885 of 1,000 patients. Transfusions were required by 472 of 1,000. Risk factors as significant predictors of increased CTD and use of blood products were emergency surgery status, increased cross‐clamp time, and higher predicted risk of mortality. The only significant predictor of decreased CTD was the use of a centrifugal pump. Predictors of increased length of stay were myocardial infarction, preoperative urea, age, and massive transfusion. Data provide evidence that use of the centrifugal pump improves patient outcomes by decreasing CTD and decreasing the requirements for transfusion, which results in a shorter hospital stay.
Preconditioning Reduces QTc Value in Patients with First Non‐ST‐Segment Elevation Myocardial Infarction (NSTEMI)
Authors: Papadopoulos Christodoulos E. , Karvounis Haralampos I. , Parharidis Georgios E. , Louridas Georgios E.
Published: October 2003

Background: Preinfarction angina (PA) consists a strong clinical correlate to ischemic preconditioning (PC) and seems to occur in a bimodal time course. The aim of the study is to evaluate the impact of both forms of PC on QTc value representing myocardial electric stability, in patients with a first NSTEMI.

Methods: Forty‐eight patients, with first NSTEMI and poor or no collateral development were enrolled in the study. QTc at admission and discharge were recorded. All patients had comparable admission QTc values and were divided into three groups according to the absence or presence and exact timing of preinfarction angina. The first group consisted of 20 patients who did not report PA (PA−, representing no PC effect); the second group of 12 patients with reported PA within 12 hours prior to admission (12h PA+, representing the classic form of PC); and the third group of 16 patients reporting PA within 12 to 48 hours prior to admission (48‐hour PA+, representing the delayed form of PC). The primary outcome was determined as the effect of PA on QTc value at discharge.

Results: Discharge QTc values were significantly reduced in both (PA+) groups compared to (PA−) group (412 ± 50 vs. 455 ± 53 ms, p = 0.015 and 417 ± 29 vs. 455 ± 53 ms, P = 0.033, respectively). Both groups of (PA+) patients compared to (PA−) patients suffered no arrhythmic events during their hospitalization (0/12 vs. 6/20, P = 0.04 and 0/16 vs. 6/20, P = 0.02).

Conclusions: Both forms of preconditioning, similarly and significantly reduce QTc value at discharge in patients experiencing a first NSTEMI, suggesting possible protection from future arrhythmic events.
The Effect of Exercise to P Wave Dispersion and Its Evaluation as a Predictor of Atrial Fibrillation
Authors: Yiğit Zerrin , Akdur Hülya , Ersanli Murat , Ökçün Bariş , Güven Özen
Published: October 2003

Aim: Prolongation of P wave time and increase of its dispersion as an independent predictor of atrial fibrillation. In patients with paroxysmal atrial fibrillation (PAF) as in healthy people, exercise augments sympathetic activity and therefore can cause the development of atrial fibrillation. The aim of this study is to evaluate the effect of exercise on P wave dispersion and to predict the development of atrial fibrillation.

Methods: One hundred and ninety‐eight patients (93 women, 105 men, mean age: 59.05 ± 11.01 years) having the diagnosis of PAF were included in the study. The left atrial diameter of all these patients was more than 4.0 cm. One hundred and fifty‐five patients (72 females, 83 males, mean age: 58.41 ± 10.79 years), with left atrial diameter more than 4.0 cm and without PAF were taken as control group. Symptom limited exercise test with modified Bruce protocol was performed on all patients. Rest, maximum exercise and recovery, and first, third, and fifth‐minute 12‐derivation ECG was taken in all patients. The velocity of ECG was adjusted to 50 mm/s; shortest and largest P wave durations were measured and P wave dispersion was calculated.

Results: The mean left atrial diameter was 4.41 ± 0.58 cm in PAF patients and 4.38 ± 0.48 cm in control group. No differences were found between PAF patients with the controls in exercise time (10.38 ± 2.93 vs 10.81 ± 2.75 minutes); METs (6.98 ± 1.72 vs 7.28 ± 1.75 minutes); resting heart rate (79.13 ± 14.86 vs 79.69 ± 10.43 bpm); peak heart rate (146.83 ± 23.21 vs 146.94 ± 16.13 bpm). Maximum exercise P wave duration and P wave dispersion were greater than the rest measurements in PAF group (respectively P < 0.0001 and P = 0.0004).

Conclusion: In PAF patients, P wave dispersion is significantly longer at rest, maximum exercise and recovery time than in a control group without PAF.
Heart Rate Variability: Short‐Term Studies are as Useful as Holter to Differentiate Diabetic Patients from Healthy Subjects
Authors: Migliaro Eduardo R. , Canetti Rafael , Contreras Paola , Hakas Michel
Published: October 2003

Background: The definitive incorporation of heart rate variability (HRV) as a clinical tool depends on the development of more confident techniques of measurement. The length of the studies is a critical issue. Whereas Holter studies allow the monitorization at different hours and activities, short‐term recordings allow the control of environmental conditions. Recording length is also strongly related to the procedure of analysis; for instance, some time‐domain indexes are strongly affected by the duration of the study. Meanwhile, spectral analyses require stationary conditions, only achieved in short‐term studies. Our main goal was to determine if HRV indexes obtained from short‐term analyses were as useful as those from Holter monitoring for diagnosis of reduced HRV in diabetes.

Methods: We studied two groups: one with impaired HRV (15 diabetic patients) and another with normal HRV (15 healthy subjects). HRV indexes obtained from 24‐hour Holter recordings (SDNN, rMSSD, and the power of LF and HF bands), were correlated with analog indexes obtained from 10‐minute digital acquired studies within each group. Besides, we compared the diabetic and control groups using the indexes obtained with both methodologies.

Results: The correlation was high (0.70≤r ≤ 0.85, P ≤ 0.0032) in the diabetic group, but was poor in the control group. HRV values were significantly lower in the diabetic group either for 24‐hour or short‐term studies (P ≤ 0.0113).

Conclusion: We conclude that short‐term studies are at least as powerful as Holter to differentiate the diabetic group (impaired HRV) from the control group.
The influence of ant‐attendance on aphid behaviour investigated with the electrical penetration graph technique
Authors: Rauch Gisep , Simon Jean‐Christophe , Chaubet Bernard , Haack Lucie , Flatt Thomas , Weisser Wolfgang W.
Published: October 2003

For the mutualistic interaction between the aphid Metopeurum fuscoviride Stroyan (Homoptera: Aphididae) and the ant Lasius niger L. (Hymenoptera: Formicidae) it has been shown that ant‐tended aphids develop faster, reproduce at a higher rate, and live longer than aphids not tended by ants. We used electrical penetration graphs (EPG) to investigate if behavioural patterns differ between ant‐tended and untended M. fuscoviride during 8 h experiments. Measurements were made on adult aphids from four different ant‐tended colonies that continued to be tended by L. niger during the experiments, and from four different colonies where ant workers were excluded several days before the start of the experiment and that were also not tended by ants during the experiments. Ants readily tended wired aphids and ant tending did not interfere with the EPG measurements. There were no significant differences in the duration of sieve element penetration or in any other analysed feeding‐related EPG parameters between ant‐tended and untended individuals. However, the quality of the EPG recordings did not allow the distinction between the EPG‐waveform E1 (salivation only) and E2 (salivation and ingestion). These results suggest that the changes in life‐history traits of ant‐tended aphids do not result from changes in time of sieve element penetration waveforms. Alternative mechanisms may involve an increase in the rate of sap uptake or a higher effectiveness in nutrient uptake in the presence of ants. Our study demonstrates that the EPG technique is a useful tool to investigate the feeding behaviour of aphids during interactions with ants.
Effects of selected botanical insecticides on the behaviour and mortality of the glasshouse whitefly Trialeurodes vaporariorum and the parasitoid Encarsia formosa
Authors: Simmonds M.S.J. , Manlove J.D. , Blaney W.M. , Khambay B.P.S.
Published: October 2003

Toxicity and behavioural bioassays were used to assess the lethal and sub‐lethal effects of two naphthoquinones from the Chilean plant Calceolaria andina L. (Scrophulariaceae), two products derived from Azadirachta indica and pyrethrum on the glasshouse whitefly, Trialeurodes vaporariorum Westwood, and the parasitoid Encarsia formosa Gahan. The potential use of these botanicals in an Integrated Pest Management (IPM) programme is discussed. Pyrethrum was the most toxic botanical tested, but it was toxic to both the whitefly and parasitoid. The naphthoquinones showed potential for inclusion into an IPM programme if, by formulation, the toxicity towards the whitefly could be increased and the deterrent activity towards E. formosa adults decreased. Overall, the A. indica‐derived products had the most potential for use in an IPM system for the control of whitefly, which includes E. formosa as a biocontrol agent.
Olfactory antennal responses of the vine weevil Otiorhynchus sulcatus to plant volatiles
Authors: van Tol R.W.H.M. , Visser J.H.
Published: October 2003

Electroantennograms (EAGs) were recorded from the vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae) to a broad range of volatile plant compounds. The response profile is restricted to a small number of volatiles that evoke substantial EAGs. Large EAG responses were particularly found among green leaf volatiles (GLV) such as (E)‐2‐hexenol‐1, (Z)‐3‐hexenol‐1, hexanol‐1, hexanal, and heptanal. Other plant volatiles eliciting responses in the weevils' antenna are 2,5‐dimethylpyrazine, hexylamine, benzylalcohol, 1,2‐dimethoxybenzene, o‐cresol, myrtenol, 3‐methylcyclohexanol, γ‐hexalactone, and γ‐heptalactone. EAG responses to terpenes were generally weak. Many of the monoterpenes are characteristic for the odour of conifers, a group of plants which tend to be avoided by adult vine weevils. The EAG response to several GLV and benzene derivatives in three geographically distinct populations of the vine weevil differed, suggesting between‐population variation in receptor sensitivities for several compounds under test. The GLV‐composition of the odour profile of potential food plants may be an important criterion for a polyphagous insect like the vine weevil to be used in host‐plant selection, since compounds in this odour group dominate so strongly the EAG response profile. In multiple food‐choice situations the weevils are known to prefer certain plant species and we hypothesize that they combine GLV information with that of more specific plant volatiles, thereby promoting attraction or avoidance.
Adaptation of the gypsy moth to an unsuitable host plant
Authors: Lazarević J. , Perić‐Mataruga V. , Stojković B. , Tucić N.
Published: October 2003

The pattern of adaptation with regard to life history traits and traits thought to be important in feeding habits of caterpillars in two populations of the gypsy moth (Lymantria dispar L.; Lepidoptera: Lymantriidae) originating from the locust tree (Robinia pseudoacacia; Fabaceae) and oak (Quercus petrea; Fagaceae) forests were investigated in the laboratory. The Robinia population has experienced unsuitable locust tree leaves as an exclusive food resource for more than 40 years. Since Quercus species are the principal host plants of the gypsy moth, the specific objectives of this study have been to measure the extent of differentiation between ancestral and derived populations in several life history traits (egg‐to‐adult viability, duration of larval and pupal stages, and pupal weight) and nutritional indices – relative growth rate (RGR), relative consumption rate (RCR), assimilation efficiency (AD), gross growth efficiency (ECI), and net growth efficiency (ECD). Significant differences between the Quercus and Robinia populations were detected in pupal duration, RGR, RCR, and AD. The presence of a significant population × host interaction in traits such as preadult viability, duration of pupal stage, RGR, and ECI suggests that adaptation of the gypsy moth to the unsuitable host might be ongoing. Using a full‐sib design, we screened for genetic variation in life history traits within both populations, and examined the genetic correlations of performance across oak and locust leaves within both populations. The genetic variances for analyzed life history traits were lower under conditions that are commonly encountered in nature. Our data show that positive cross‐host genetic correlations preponderate within both populations.
Life history of Bicyclus anynana mutants: Can they serve as internal controls?
Authors: Zijlstra Wilte G. , Zwaan Bas J. , Brakefield Paul M.
Published: October 2003

Correction for environmental effects in quantitative genetics experiments is often achieved by use of separate control populations. However, this method may not always correct accurately for environmental fluctuations in rearing conditions. A more suitable approach could be rearing mutants together with experimental groups, provided that these mutants are clearly distinguishable phenotypically and have similar life histories. We tested whether two mutants (yellow and Spotty) available for the tropical butterfly Bicyclus anynana could serve as such true internal controls. The yellow butterflies had lower survival and longer development time than the wild type animals they were reared with, whereas Spotty individuals were equivalent in those respects to their wild type counterparts. Moreover, heritability estimates for development time in the Spotty stock were mostly significantly different from zero and fell within the range found for wild type butterflies. Therefore, we conclude that a backcrossed stock homozygous for the Spotty mutant of B. anynana can reliably serve as an internal control in life‐history studies and we discuss potential advantages of this method.
Influence of water‐stressed cassava on Phenacoccus herreni and three associated parasitoids
Authors: Calatayud P.A. , Polanía M.A. , Seligmann C.D. , Bellotti A.C.
Published: October 2003

The influence of cassava Manihot esculenta Crantz grown under condition of water‐stress on development and reproduction of the cassava mealybug, Phenacoccus herreni Cox & Williams, and levels of parasitism of three encyrtid parasitoids, Apoanagyrus diversicornis Howard, Aenasius vexans Kerrich, and Acerophagus coccois Smith, were studied in the laboratory. Two cassava cultivars were used: CM 507‐37 (drought‐tolerant) and CMC 40. A 30 day period of water stress, imposed by reducing the irrigation volume, led to a reduction in shoot development and stomatal conductance of leaves of both cassava genotypes. Phenacoccus herreni development and reproduction were favoured by cassava under water shortage. Parasitism decreased and water stress appeared to enhance the encapsulation of parasitoid eggs or larvae by the mealybug. In the case of the parasitoid A. diversicornis, there was a decrease in size of female progeny, suggesting a lower fitness in this species on cassava plants under water stress. All results indicated that cassava grown under low water availability favoured P. herreni development and reproduction, and affected the success of parasitism and, depending on the species, parasitoid development. The drought‐tolerance characteristic of cassava genotypes and parasitoid species most suitable for controlling P. herreni in drought‐stricken areas are discussed.
Variation in the effectiveness of abdominal shields of cassidine larvae against predators
Authors: Müller Caroline
Published: October 2003

The abdominal shields of the larvae of two tansy [Tanacetum (Chrysanthemum) vulgare L., Asteraceae] feeding species of Cassida (Coleoptera: Chrysomelidae) were tested for their ability to deter attacks by predatory insects. Cassida stigmatica Suffr. which carries an abdominal shield made of the exuviae only, and C. denticollis Suffr. which builds a compact faecal shield, were compared. Adult earwigs (Forficula auricularia L., Dermaptera: Forficulidae), adult ladybird beetles (Coccinella septempunctata (L.), Coleoptera: Coccinellidae), and larval lacewings (Chrysoperla carnea Steph., Neuroptera: Chrysopidae) were used as predators and tested in dual choice bioassays. Against earwigs, shields of both cassidine species acted as a protective device. Earwigs preferred to feed on larvae without shields over larvae with intact shields. Adult ladybirds did not differentiate between C. stigmatica larvae with and without exuvial shields. However, C. denticollis larvae with faecal shields were contacted at a higher frequency by ladybird beetles, even though they were less often consumed, i.e., their shield served as protection. In an olfactometer assay, faecal shields of C. denticollis were shown to have no attractive effect on the ladybird beetles. The protection for larvae with shields is likely to be caused by mechanical effects, namely the ability to move the shields. Control insects, where faecal shields of C. denticollis were glued on larvae of Galleria mellonella L. (Lepidoptera: Pyralidae), could not move their shields and were consequently consumed by the predator. Feeding by larvae of lacewings was not influenced by the presence or absence of the faecal shield. Thus, the effectiveness of the abdominal shields of tansy‐feeding cassidine larvae varies with predator species, and might be based more on mechanical, than on chemical modes of action.
Courtship in the medfly, Ceratitis capitata, includes tactile stimulation with the male's aristae
Authors: Briceño R. Daniel , Eberhard William G.
Published: October 2003

Male Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) used their aristae to repeatedly tap the female, usually on her aristae, during the second stage of head rocking courtship. The male's antennae moved in an apparently exploratory manner earlier in head rocking. Reduced rates of copulation followed removal of male and female aristae, supporting the idea that tapping with the aristae is an important part of medfly courtship.
Pheromone puffs suppress mating by Plodia interpunctella and Sitotroga cerealella in an infested corn store
Authors: Fadamiro Henry Y. , Baker Thomas C.
Published: October 2003

The efficacy of pheromone mating disruption was investigated in a 7 × 6 × 3 m corn storage room harboring a high population density of Indian meal moth, Plodia interpunctella (Hübner) and Angoumois grain moth, Sitotroga cerealella (Olivier). Pheromones were released from a controlled release dispenser, the metered semiochemical timed release system (MSTRS™) at emission rates of ∼ 0.6 μg min−1 (Z9,E12:14:Ac for Indian meal moth) and ∼ 0.2 μg min−1 (Z7,E11‐16:Ac for Angouimois grain moth). Mating disruption efficacy was evaluated using three parameters: male capture in pheromone traps, visual examination of mating behavior, and the incidence and frequency of mating as measured by spermatophores. In three trials, comparisons were made between data collected before pheromone treatment and during treatment. Disruption of pheromone source location by males averaged 70% and 40% for P. interpunctella and S. cerealella, respectively, in the three trials. In addition, reduced levels of copulation by both species were recorded during pheromone treatment. More importantly, significant reductions were recorded in the incidence and frequency of mating by females of both species collected during the treatment period. While ∼ 85% of P. interpunctella females collected before pheromone treatment in three trials had mated at least once, only 50% of the females collected during treatment had mated. The mean number of matings, as measured by spermatophores, ranged between 0.8–1.1 and 0.5–0.7 before and during pheromone treatment, respectively. Similarly, a ∼ 20–30% reduction in the proportion of mated S. cerealella females was recorded during pheromone treatment. In the three trials, mean number of spermatophores per S. cerealella female averaged 1.0 and 0.7 during the pretreatment and treatment periods, respectively. Additional tests conducted in small boxes also recorded significant mating disruption of both species.
Developing a branch‐mimicking trap for adult plum curculios
Authors: Leskey Tracy C. , Prokopy Ronald J.
Published: October 2003

We conducted field and semi‐field experiments to determine the most visually stimulating and acceptable version of a branch‐mimicking trap (PVC cylinder topped with an inverted screen funnel) to capture adult plum curculios, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae) foraging within canopies of host trees. Cylinder traps (25 cm tall × 6 cm diam) coated with different colors of gloss or flat latex paint captured similar numbers of feral adults in field tests. Tall cylinder traps (50 cm tall × 6 cm diam) captured significantly more feral adults in field tests in 1999 than cylinder traps of lesser height and/or different diameter, and significantly more released adults arrived at traps with these dimensions compared to cylinder traps of lesser height in semi‐field tests. In field and semi‐field tests, respectively, significantly more adults were captured by and numerically more adults arrived at tall cylinder traps (50 cm tall × 6 cm diam) attached in an upright, standard position to a horizontal limb than attached at angles of 45°, 90°, 135°, or 180° to horizontal limbs.
Oviposition behaviour of the aphid parasitoid, Aphidius ervi: Are wet aphids recognized as host?
Authors: Weinbrenner Manuela , Völkl Wolfgang
Published: October 2003

Females of the central European population of the aphid parasitoid, Aphidius ervi, did not attack wet pea aphids (Acyrthosiphon pisum) that were washed previously with water. After 1 hour, this phenomenon disappeared and A. ervi attacked washed hosts to the same degree as dry ones. Similarly, A. ervi attacked dead aphids killed in liquid nitrogen readily if they were dry but not if they were wet. This effect was also reversible and disappeared after 1 h. When A. ervi females were foraging on broad beans (Vicia faba), they laid significantly more eggs into dry aphids than into wet aphids. Resource utilization of wet aphids, however, was significantly lower in this design than in Petri dishes, due to a changed drop‐off behaviour of the aphid. We conclude that females did not use visual cues for host recognition but instead relied on chemical cues. These cues may be covered by a thin water layer directly after aphids became wet. Our results also demonstrate the importance of abiotic factors for the estimation of the reproductive success of parasitoids in the field.