bluuebunny/crossref_metadata_2025_split huggingface dataset:
A long‐term record of Nothofagus dominance in the southern Andes, Chile
Authors: Pollmann William 
Published: February 2005

Abstract  The general model of regeneration dynamics in Nothofagus forests of southern South America could have value in community ecology if predictive relationships between disturbance history, functional traits and site attributes could be identified. Examined here is the proposal that on favourable sites shade‐intolerant Nothofagus are likely not to survive in competition with shade‐tolerant, broad‐leaved evergreen taxa of temperate rain forests, and persistence, thus, is dependent on periodic coarse‐scale disturbance. Comparison of stand dynamics of three old‐growth Nothofagus forests at different elevations in the southern Andes, Chile where deciduous Nothofagus alpina dominates the upper canopy, and examination of the life history trade‐offs of this variation were made. Stem density of all stems ≥5.0 cm d.b.h. was 233–303 stems per hectare, and basal area was 123.9–171.0 m2ha−1. Maximum lifespan of N. alpina was found to be greater than ca 640 years, exceeding all previously reported ages for this species in the region. Forests had a stable canopy composition for this long‐term, but some appeared to lack effective regeneration of N. alpina in recent years. Regeneration of N. alpina was generally greater in disturbed stands and higher elevation than in undisturbed stands and at lower elevation. Recruitment emerged to be strongly affected by competitive over‐ and understorey associates. There was a gradient of increasing dependence of N. alpina on disturbance towards the more productive end of the environment gradients, and hence less dependence of N. alpina on disturbance for its regeneration towards higher elevation. The study confirms that changes in forest composition may be explained by processes occurring in accordance with the predictions of the existing model of Nothofagus regeneration dynamics, providing stronger evidence specifically directed at mid‐tolerant N. alpina, and by factoring out regeneration dynamics on favourable sites. Thus, for N. alpina, trait differences probably contribute to the competitive advantage over its associates in productive habitats, and may be linked to small‐to‐intermediate‐sized disturbances which inevitably occur as older trees die, enabling N. alpina to persist in forests and therefore maintain species coexistence for the long‐term.
Electrophysiological and Histopathological Characteristics of Progressive Atrioventricular Block Accompanied by Familial Dilated Cardiomyopathy Caused by a Novel Mutation of Lamin A/C Gene
Authors: OTOMO JUN , KURE SHIGEO , SHIBA TOMOKO , KARIBE AKIHIKO , SHINOZAKI TSUYOSHI , YAGI TETSUO , NAGANUMA HIROSHI , TEZUKA FUMIAKI , MIURA MASAETSU , ITO MEIICHI , WATANABE JUN , MATSUBARA YOICHI , SHIRATO KUNIO 
Published: February 2005

Introduction: Mutations of lamin A/C gene (LMNA) cause dilated cardiomyopathy (DCM) with atrioventricular (AV) conduction defect, although the electrophysiological and histological profiles are not fully understood. Methods and Results: We analyzed a large Japanese family (21 affected and 203 unaffected members) of DCM with AV block. The responsible LMNA mutation of IVS3–10A>G was novel and caused an aberrant splicing. The first clinical manifestation was low‐grade AV block or atrial fibrillation (AF), which developed in affected members aged ≥30 years. We observed that the AV block progressed to third‐degree within several years. The electrophysiological study of the four affected members revealed an impairment of intra‐AV nodal conduction. Because of advanced AV block, pacemakers were implanted in 14 out of 21 affected members at the mean age of 44 years. Three affected members died suddenly and two affected members died of heart failure and/or ventricular tachycardia (VT) even after the pacemaker implantation. Postmortem examination showed conspicuous fibrofatty degeneration of the AV node. Endomyocardial biopsies showed remarkably deformed nuclei and substantial glycogen deposits in the subsarcolemma. Conclusion: The clinical phenotype in this family was characterized by (1) the first manifestation of the prolonged PQ interval or AF in adolescence, (2) progressive intra‐AV nodal block to the third degree in several years, and (3) progressive heart failure after pacemaker implantation. Histological study revealed preferential degeneration at the AV node area and novel cellular damages in the working myocardium.
Numerical Simulation of Paced Electrogram Fractionation: Relating Clinical Observations to Changes in Fibrosis and Action Potential Duration
Authors: TURNER IAN , L.‐H. HUANG CHRISTOPHER , SAUMAREZ RICHARD C 
Published: February 2005

Introduction: Paced electrogram fractionation analysis (PEFA) may identify a re‐entrant substrate in patients at risk of ventricular fibrillation (VF) by detecting prolonged, fractionated ventricular electrograms (“fractionation”) in response to premature extrastimuli. Numerical simulations of action potential (AP) propagation through human myocardium following such premature stimulation were performed to study the relationship between electrogram fractionation, fibrosis, and changes in AP currents. Methods and Results: Activation in a resistive monodomain 2 cm2 sheet of myocardium containing nonconducting fibrous tissue was modeled using standard numerical methods for solutions of partial differential equations using the Priebe–Beukelmann (PB) AP equations. Myocardial fibrosis significantly influenced electrogram morphology. High densities of closely spaced fibrous septa caused functional block and altered propagation paths at short coupling intervals, and produced large increases in electrogram duration similar to those associated with increased risk of VF in clinical studies. Prolongation of the cardiac AP using the heart failure variant of the PB model further increased the amount of fractionation and thereby replicated clinical recordings more closely than did fibrosis alone. Increasing AP dispersion by a variable reduction in the potassium current IKr simulated results seen in patients with the long QT syndrome with an abrupt increase in electrogram duration, while a uniform reduction in IKr alone did not result in fractionated electrograms. In contrast, increases in cytosolic Ca2+ and Ca2+ buffering by troponin to simulate HCM had little effect on fractionation. Conclusions: These results relate the effects of fibrosis, AP abnormalities, and dispersion of AP duration to the characteristic electrograms recorded in patients at risk of sudden death.
Characterization of Right Atrial Substrate in Patients with Supraventricular Tachyarrhythmias
Authors: LIN YENN‐JIANG , TAI CHING‐TAI , HUANG JIN‐LONG , LEE KUN‐TAI , LEE PI‐CHANG , HSIEH MING‐HSIUNG , LEE SHIH‐HUANG , HIGA SATOSHI , YUNIADI YOGA , LIU TU‐YING , CHEN SHIH‐ANN 
Published: February 2005

Background: Voltage mapping has been used to detect diseased myocardium. However, accurate determination of the local atrial voltage at the same site, and simultaneous recordings from multiple mapping sites were limited. The purpose of this study was to investigate the right atrial (RA) substrate properties in patients with supraventricular tachyarrhythmias (SVT). Methods and Results: Forty patients (aged 55 ± 20 years) undergoing noncontact mapping and ablation of SVT constituted the study population. There were eight patients with atrioventricular node reentrant tachycardia (AVNRT), eight patients with focal atrial tachycardia (AT), 14 patients with atrial flutter (AFL), and 10 patients with atrial fibrillation (AF). The mean peak negative voltage (PNV) was analyzed in virtual unipolar electrograms, which were obtained from 256 equally distributed RA endocardial sites during sinus rhythm (SR), atrial pacing, and tachycardia. The mean PNV of global RA during SR (−1.34 ± 0.22 vs. −0.90 ± 0.40 vs. −1.00 ± 0.36 vs. −0.85 ± 0.35 mV, P = 0.04), atrial pacing at cycle lengths of 500 ms (−1.30 ± 0.29 vs. −0.70 ± 0.35 vs. −0.76 ± 0.25 vs. −0.64 ± 0.26 mV, P = 0.02), and 300 ms (−1.54 ± 0.47 vs. −0.94 ± 0.21 vs. −0.75 ± 0.27 vs. −0.57 ± 0.22 mV, P < 0.01) were significantly greater in patients with AVNRT compared to AT, AFL, and AF. Furthermore, the mean PNV decreased during atrial pacing with shorter pacing cycle length was demonstrated only in patients with AFL and AF. Conclusion: Negative unipolar voltage analysis of global RA showed different RA substrate characteristics during various SVT. The substrate property of activation and cycle length‐dependent voltage reduction may be related to the development of AFL and AF.
The High Frequency Magnetic Field of a Flat Spiral Coil
Authors: Githens Sherwood , Stuhlman Otto 
Published: February 2005

The high frequency magnetic field of a flat spiral coil, with an inner opening about one-fourth the diameter of the coil, was excited by single-tube tuned plate-tuned grid and push-pull oscillators. Frequency range 1500 to 6000 kc/sec. The magnetic fields thus excited were compared with the fields produced by a direct current. The results when a push-pull oscillator was used to excite the high frequency field showed no apparent difference, except near the far edges lying about 25 cm from the center of the coil, and were independent of frequency.
Unbalanced high frequency excitation showed magnetic field crowded toward the normal axis when filament lead was connected to inner turn of spiral. Field strength across inner diameter was found to be non-uniform when field was excited by a balanced push-pull oscillator. Field strength along normal axis of coil diminished more rapidly for a balanced than for unbalanced excitation, independent of method of lead connections and was much smaller for the case of filament lead connected to outer end of spiral.
Increased Sensitivity to Thermal Pain and Reduced Subcutaneous Lidocaine Efficacy in Redheads
Authors: Liem Edwin B. , Joiner Teresa V. , Tsueda Kentaro , Sessler Daniel I. 
Published: February 2005

Background
Anesthetic requirement in redheads is exaggerated, suggesting that redheads may be especially sensitive to pain. Therefore, the authors tested the hypotheses that women with natural red hair are more sensitive to pain and that redheads are resistant to topical and subcutaneous lidocaine.

Methods
The authors evaluated pain sensitivity in red-haired (n = 30) or dark-haired (n = 30) women by determining the electrical current perception threshold, pain perception, and maximum pain tolerance with a Neurometer CPT/C (Neurotron, Inc., Baltimore, MD). They evaluated the analogous warm and cold temperature thresholds with the TSA-II Neurosensory Analyzer (Medoc Ltd., Minneapolis, MN). Volunteers were tested with both devices at baseline and with the Neurometer after 1-h exposure to 4% liposomal lidocaine and after subcutaneous injection of 1% lidocaine. Data are presented as medians (interquartile ranges).

Results
Current perception, pain perception, and pain tolerance thresholds were similar in the red-haired and dark-haired women at 2,000, 250, and 5 Hz. In contrast, redheads were more sensitive to cold pain perception (22.6 [15.1-26.1] vs. 12.6 [0-20] degrees C; P = 0.004), cold pain tolerance (6.0 [0-9.7] vs. 0.0 [0.0-2.0] degrees C; P = 0.001), and heat pain (46.3 [45.7-47.5] vs. 47.7 [46.6-48.7] degrees C; P = 0.009). Subcutaneous lidocaine was significantly less effective in redheads (e.g., pain tolerance threshold at 2,000-Hz stimulation in redheads was 11.0 [8.5-16.5] vs. > 20.0 (14.5 to > 20) mA in others; P = 0.005).

Conclusion
Red hair is the phenotype for mutations of the melanocortin-1 receptor. Results indicate that redheads are more sensitive to thermal pain and are resistant to the analgesic effects of subcutaneous lidocaine. Mutations of the melanocortin-1 receptor, or a consequence thereof, thus modulate pain sensitivity.
The Impact of Pharmacogenomics on Postoperative Nausea and Vomiting
Authors: Candiotti Keith A. , Birnbach David J. , Lubarsky David A. , Nhuch Fani , Kamat Aimee , Koch Walter H. , Nikoloff Michele , Wu Lin , Andrews David 
Published: February 2005

Background
Some patients treated with ondansetron for postoperative nausea and vomiting do not respond to therapy. One possible mechanism for this failure is ultrarapid drug metabolism via the cytochrome P-450 system, specifically the enzyme 2D6 (CYP2D6). Ultrarapid metabolism is seen in patients with multiple functional copies (>/= 3) of the CYP2D6 allele. This study was designed to determine whether patients who were given prophylactic ondansetron and had multiple CYP2D6 alleles had an increased rate of postoperative nausea and vomiting.

Methods
Two hundred fifty female patients undergoing standardized general anesthesia were given 4 mg ondansetron 30 min before extubation. Patients were observed for symptoms of nausea and vomiting. DNA was extracted from blood in all patients and was analyzed by using a gene-specific probe to determine the CYP2D6 gene copy number and genotyped by polymerase chain reaction amplification with a custom oligonucleotide microarray to determine the specific CYP2D6 genotypes.

Results
Eighty-eight patients experienced nausea, and 37 of those patients also had vomiting. In patients with one, two, or three CYP2D6 copies, the incidences of vomiting were 3 in 33 (27%), 27 in 198 (14%), and 7 in 23 (30%), respectively. The incidence of vomiting in subjects with three CYP2D6 copies was significantly different from those with two copies, but not from those with one copy. When analyzed by genotype, the incidences of vomiting in poor, intermediate, extensive, and ultrarapid metabolizers were 1 in 12 (8%), 5 in 30 (17%), 26 in 176 (15%), and 5 in 11 (45%), respectively (P < 0.01 vs. all other groups). There were no differences between groups in the incidence of nausea based on CYP2D6 copy number or genotype.

Conclusions
Patients with three copies of the CYP2D6 gene, a genotype consistent with ultrarapid metabolism, or both have an increased incidence of ondansetron failure for the prevention of postoperative vomiting but not nausea.
Awakening Concentration of Desflurane Is Decreased in Patients with Obstructive Jaundice
Authors: Song Jian-Gang , Cao Yun-Fei , Yang Li-Qun , Yu Wei-Feng , Li Quan , Song Jin-Chao , Fu Xiao-Yong , Fu Qiang 
Published: February 2005

Background
Some studies suggest that behavioral complications of cholestasis, such as fatigue and pruritus, may be associated with altered neurotransmission in the brain. Because inhaled anesthetics primarily act on ion channels and receptors on the neuronal cell membrane and alter synaptic transmission in the central nervous system, it is possible that altered sensitivity to inhaled anesthetics may occur in cholestatic patients. Therefore, the authors compared the minimum alveolar concentration (MAC)-awake of desflurane in obstructive jaundiced patients with the MACawake in nonjaundiced patients.

Methods
Patients underwent inhalational induction of anesthesia with desflurane. MACawake was determined in each patient by observing the response to a verbal command (open eyes on request). An end-tidal anesthetic concentration was maintained at an initial target level of 1.4% for 15 min before a command. If a positive response was observed, the concentration of desflurane was increased by 0.1% and again kept constant for 15 min. The verbal command was then continued. This process was repeated until an end-tidal concentration was reached at which the patient did not respond to command. The anesthetic concentration midway between the value permitting the response and that just preventing the response was defined as MACawake for each patient.

Results
The MACawake of desflurane for patients with obstructive jaundice (1.78 +/- 0.19%) was significantly less than those observed for the control group (2.17 +/- 0.25%; P < 0.001) and correlated significantly with serum total bilirubin (r = -0.67, P = 0.0004).

Conclusions
The MACawake of desflurane is reduced in obstructive jaundiced patients compared with nonjaundiced controls.
Effects of Bispectral Index Monitoring on Recovery from Surgical Anesthesia in 1,580 Inpatients from an Academic Medical Center
Authors: Pavlin Janet D. , Souter Karen J. , Hong Jae Y. , Freund Peter R. , Bowdle T Andrew , Bower Jan O. 
Published: February 2005

Background
The purpose of this study was to determine whether monitoring Bispectral Index (BIS) would affect recovery parameters in patients undergoing inpatient surgery.

Methods
Anesthesia providers (n = 69) were randomly assigned to one of two groups, a BIS or non-BIS control group. A randomized crossover design was used, with reassignment at monthly intervals for 7 months. Duration of time in the postanesthesia care unit, time from the end of surgery to leaving the operating room, and incidence of delayed recovery (> 50 min in recovery) were compared in patients treated intraoperatively with or without BIS monitoring. Data were analyzed by analysis of variance, unpaired t test, or chi-square test as appropriate.

Results
One thousand five hundred eighty patients in an academic medical center were studied. The mean BIS in the monitored group was 47. No differences were found in recovery parameters between the BIS-monitored group and the control group when comparisons were made using all subjects or when data were analyzed within anesthetic subgroups stratified by anesthetic agent or duration of anesthesia. There were some small reductions in the intraoperative concentration of sevoflurane (but not isoflurane).

Conclusions
The use of BIS monitoring for inpatients undergoing a wide variety of surgical procedures in an academic medical center had some minor effects on intraoperative anesthetic use but had no impact on recovery parameters.
Ketamine Attenuates Acetylcholine-induced Contraction by Decreasing Myofilament Ca2+Sensitivity in Pulmonary Veins
Authors: Ding Xueqin , Damron Derek S. , Murray Paul A. 
Published: February 2005

Background
The authors investigated the extent and cellular mechanisms by which the intravenous anesthetic ketamine alters acetylcholine-induced contraction in pulmonary veins (PVs). They tested the hypothesis that ketamine inhibits acetylcholine contraction in PVs.

Methods
Canine PV rings with endothelium (E+) and without endothelium (E-) were isolated for measurement of isometric tension. The effects of ketamine (10(-5) m approximately 10(-3) m) on acetylcholine contraction were assessed in E+ and E- rings. The effects of inhibiting nitric oxide synthase on ketamine-induced changes in acetylcholine contraction were investigated in E+ rings, whereas the effects of Ca2+ influx and Ca2+ release were investigated in E- rings. In fura-2 loaded E- PV strips, the effects of ketamine (10(-4) m) on the intracellular Ca2+ concentration-tension relation (i.e., myofilament Ca sensitivity) were assessed in the presence or absence of acetylcholine. The roles of the protein kinase C and rho-kinase signaling pathways in ketamine-induced changes in myofilament Ca2+ sensitivity were also investigated.

Results
Ketamine caused dose-dependent (P < 0.001) inhibition of acetylcholine contraction in E+ and E- PV rings. The ketamine-induced attenuation of acetylcholine contraction was still observed after inhibition of nitric oxide synthase (P = 0.002), Ca2+ influx (P < 0.001), and Ca2+ release (P = 0.021). Ketamine alone had no effect on myofilament Ca2+ sensitivity (P = 0.892) but attenuated (P = 0.038) the acetylcholine-induced increase in myofilament Ca2+ sensitivity. This attenuation was still observed after rho-kinase inhibition (P = 0.039), whereas it was abolished by protein kinase C inhibition (P = 0.798).

Conclusions
Ketamine attenuates acetylcholine contraction by inhibiting the acetylcholine-induced increase in myofilament Ca2+ sensitivity, which is mediated by the protein kinase C signaling pathway.
Vaporized Perfluorohexane Attenuates Ventilator-induced Lung Injury in Isolated, Perfused Rabbit Lungs
Authors: Gama de Abreu Marcelo , Wilmink Beate , Hübler Matthias , Koch Thea 
Published: February 2005

Background
The authors tested the hypothesis that administration of vaporized perfluorohexane may attenuate ventilator-induced lung injury.

Methods
In isolated, perfused rabbit lungs, airway pressure-versus-time curves were recorded. At baseline, peak inspiratory pressure and positive end-expiratory pressure of mechanically ventilated lungs were set to obtain straight pressure-versus-time curves in both the lower and upper ranges, which are associated with less collapse and overdistension, respectively. After that, peak inspiratory pressure and positive end-expiratory pressure were set at 30 cm H2O and 0, respectively, and animals were randomly assigned to one of two groups: (1) simultaneous administration of 14% perfluorohexane vapor in room air (n = 7) and (2) control group-ventilation with room air (n = 7). After 20 min of cycling collapse and overdistension, tidal volume and positive end-expiratory pressure were set back to baseline levels, administration of perfluorohexane in the therapy group was stopped, and mechanical ventilation was continued for up to 60 min. Lung weight, mean pulmonary artery pressure, and concentration of thromboxane B2 in the perfusate were measured. In addition, the distribution of pulmonary perfusate flow was assessed by using fluorescent-labeled microspheres.

Results
Significantly higher peak inspiratory values developed in control lungs than in lungs treated with perfluorohexane. In addition, upper ranges of pressure-versus-time curves were closer to straight lines in the perfluorohexane group. Lung weight, mean pulmonary arterial pressure, and release of thromboxane B2 were significantly higher in controls than in perfluorohexane-treated lungs. Also, redistribution of pulmonary perfusate flow from caudal to cranial zones was less important in the treatment group.

Conclusion
The authors conclude that the administration of perfluorohexane vapor attenuates the development of ventilator-induced lung injury in isolated, perfused rabbit lungs.