bluuebunny/crossref_metadata_2025_split huggingface dataset:
Combining phylogenetic and ecological niche modeling approaches to determine distribution and historical biogeography of Black Hills mountain snails (Oreohelicidae)
Authors: Weaver Kathleen F. , Anderson Tamara , Guralnick Robert 
Published: October 2006

ABSTRACTWe aim to show how a combination of molecular systematics and ecological niche modelling approaches can be used to test historical biogeographical hypotheses for species of conservation concern. We focus on the land snail genus Oreohelix (Oreohelicidae), a group found throughout the Rocky Mountains. In addition to its larger distribution, a group of Oreohelix is also found in the Black Hills of Wyoming and South Dakota, an isolated, easternmost extension of the Rocky Mountains. We determine the number, distribution, and relationships of Black Hills Oreohelicids, which are a current conservation concern due to their fragmented distribution. We compared Black Hills groups to those in the main part of the Rockies to test historical biogeographical patterns that explain current diversity. We collected mtDNA data (COI and 12S sequences) from multiple populations of Oreohelix throughout the Black Hills and in adjacent populations in the Rocky Mountains to construct phylogenetic hypotheses. To determine whether favourable environmental conditions currently exist between the Black Hills and the north‐eastern Rocky Mountains, we used DesktopGARP to generate an ecological niche model for distinct lineages discovered in the molecular phylogenetic analysis. Results show that all Black Hills populations are likely Oreohelix cooperi and that little genetic differentiation exists within this clade. In addition, Black Hills groups are genetically similar or identical to populations found in the Judith Mountains and Bighorn Mountains (north‐eastern Rockies). Ecological niche models show that suitable environmental conditions may exist between eastern Rockies and Black Hills O. cooperi samples. Taken together, the phylogenetic and niche model data, along with the low vagility of the snails, support passive long‐distance dispersal as a likely explanation for current arrangement of biodiversity.
Variation in peak P–T conditions across the upper contact of the UHP terrane, Dabieshan, China: gradational or abrupt?
Authors: SHI Y. , WANG Q. 
Published: October 2006

AbstractThe Southern Dabieshan Terrane (SDT) has previously been divided into high‐pressure (HP) and ultrahigh‐pressure (UHP) terranes, and its regional extent and the tectonic nature of its boundaries are hotly debated topics. In this study, an eclogite‐bearing area of 100 km2 near Taihu is mapped in detail, and divided into Northern, Middle and Southern Zones on the basis of lithological characteristics. The Northern Zone consists of epidote‐biotite gneiss and eclogite blocks, the Middle Zone includes granitic gneiss, biotite gneiss, eclogites and amphibolite, and the Southern Zone is composed mainly of garnet‐bearing mica schist. The eclogites occur mainly as lens or blocks in the Northern and Middle Zones. The peak P–T conditions for 61 eclogite samples across the area are estimated using the Grt‐Cpx Fe2+‐Mg thermometers and the Grt‐Cpx‐Phe barometers. The results indicate three different P–T regions: 2.82–4.09 GPa/759–942 °C in the Northern Zone, and 2.00–3.54 GPa/641–839 °C in the granitic gneiss and 1.38–2.36 GPa/535–768 °C in the biotite gneiss from the Middle Zone. Combined with the spatial distribution of eclogites across the area, the P–T values for eclogites increase continuously from the south to the north, defining a reference ‘geotherm’ of 5 °C km−1. However, some unreasonable apparent gradients can be established along two south–north profiles across the area, and display a P–T difference between the Northern and Middle zones. On the basis of the average P–T data for eclogites across the area, a gap of at least 0.3 GPa/20 °C exists between the Northern and Middle zones. By contrast, the P–T values of eclogites from the Middle zone show a coherent pattern with transitional characteristics from HP in the south to UHP in the north. We suggest that the SDT was a coherent slab during subduction, and was broken up by a major fault during exhumation, which was formed under UHP metamorphic conditions.
Enhanced ascertainment of microchimerism with real‐time quantitative polymerase chain reaction amplification of insertion‐deletion polymorphisms
Authors: Lee Tzong‐Hae , Chafets Daniel M. , Reed William , Wen Li , Yang Yunting , Chen Jennifer , Utter Garth H. , Owings John T. , Busch Michael P. 
Published: October 2006

BACKGROUND: The characterization of microchimerism (MC) by gene amplification has been limited by few allogeneic markers, ascertainment bias, and assay analytic performance. To address this, a panel of 12 MC assays based on insertion‐deletion (InDel) polymorphisms had been optimized.STUDY DESIGN AND METHODS: The InDel assays were validated with comprehensive in vitro spiking studies at the stochastic limit of detection. Their ability was also determined to ascertain MC of unknown source genotype with both theoretical and actual donor‐recipient pairs, and the assays were applied to a clinical population of 73 trauma patients who received transfusions where MC was previously characterized by HLA‐based assays alone.RESULTS: In the stochastic spiking experiments, all assays were sensitive to a single copy of target DNA, and no false‐positive amplification occurred among 1128 samples studied. Among 219 theoretical donor‐recipient pairs, informative alleles existed for 99.5 percent with both InDel and HLA compared to 91.3 percent with HLA alone. In the clinical population, 33 cases of MC were detected (9 more cases than by HLA‐DR alone) in the nonleukoreduced (non‐LR) group and 8 cases (1 more case than by HLA‐DR) in the LR group for the short‐term follow‐up. Among 27 long‐term follow‐up samples, 8 cases were detected overall (3 more cases than by HLA‐DR alone).CONCLUSION: It is concluded that an InDel‐based assay panel has excellent technical performance characteristics while also allowing for ascertainment of some MC cases not detectable with HLA alone. The tandem use of both the InDel and the HLA provides a powerful tool for the enhanced ascertainment of MC.
Resistance of porcine circovirus and chicken anemia virus to virus inactivation procedures used for blood products
Authors: Welch Jon , Bienek Carol , Gomperts Edward , Simmonds Peter 
Published: October 2006

BACKGROUND:Virus inactivation procedures are used to prevent contamination of plasma‐derived blood products with viruses. Pasteurization or prolonged dry heat has proven effective against several enveloped and nonenveloped viruses and provides an additional layer of safety for plasma products.STUDY DESIGN AND METHODS:The resistance of porcine circovirus 2 (PCV2) and chicken anemia virus (CAV), two small, nonenveloped viruses, to standard (pasteurization, 10 hr at 60°C; dry heating, 80°C for 72 hr) and more extreme heat inactivation procedures (temperatures up to 120°C) was determined. The ability of these procedures to inactivate PCV2 and CAV was measured by comparison of in vitro infectivity before and after treatment.RESULTS:Infectivity of PCV2 and CAV was reduced by approximately 1.6 and 1.4 log by pasteurization and by 0.75 and 1.25 log by dry‐heat treatment, both substantially more resistant than other viruses previously investigated. PCV2 and CAV were additionally almost completely resistant to dry‐heat treatment up to 120°C for 30 minutes (mean log infectivity reductions, 1.25 and 0.6), although both were more effectively inactivated when the temperature of wet‐heat treatment was increased to 80°C (>3.2 and >3.6 log infectivity reduction).CONCLUSION:Although neither PCV2 nor CAV are known to infect humans, their inactivation properties may represent those of other small DNA viruses known to be present (e.g., TT virus, small anellovirus) or potentially present in human plasma. Findings of extreme thermal resistance demonstrate that recipients of plasma‐derived therapeutics may potentially still be exposed to small DNA viruses, despite the implementation of viral inactivation steps.
Dispermic chimerism identified during blood group determination and HLA typing
Authors: Mosebach Mira , Parkner Andreas , Jakubiczka Sybille , Wieacker Peter , Heim Marcell U. 
Published: October 2006

BACKGROUND: Chimerism is the presence of two or more genetically distinct cell populations in one organism.STUDY DESIGN AND METHODS: We report the identification of dispermic chimerism in a 19‐year‐old female volunteer blood donor. During routine ABO blood grouping strong reactions of the blood donors red blood cells (RBCs) with anti‐A reagents and mixed‐field reactions with anti‐B reagents were observed, while serum‐testing showed the absence of anti‐A and anti‐B antibodies. AB0 blood group genotyping, HLA‐typing and microsatellite analysis were performed using blood‐samples, buccal mucosa and fibroblasts of the blood‐donor and blood‐samples of her parents.RESULTS: AB0 blood group genotyping showed three ABO blood group alleles (01, A2 and B) in the DNA‐samples of the blood‐donor. The evidence of chimerism was supported by the detection of three alleles for the HLA‐A and HLA‐DRB1 loci. Microsatellite analysis with ten markers revealed three alleles for loci D7S821 and D19S412. All studies carried out, the third allele was always of paternal origin.CONCLISION: The results suggested a case of a human dispermic chimerism. Our proposed explanation for the development of chimerism in the reported case is the fertilization of an oocyte and the corresponding second polar body by two different sperms.
Changes in Autonomic Activity Preceding Onset of Nonsustained Ventricular Tachycardia
Authors: Osaka Motohisa , Saitoh Hirokazu , Sasabe Noriko , Atarashi Hirotsugu , Katoh Takao , Hayakawa Hirokazu , Cohen Richard J. 
Published: October 2006

Background: The triggering role of the autonomic nervous system in the initiation of ventricular tachycardia has not been established. To investigate the relationship between changes in autonomic activity and the occurrence of nonsustained ventricular tachycardia (NSVT) we examined heart rate variability (HRV) during the 2‐hour period preceding spontaneous episodes of NSVT. Twenty‐four subjects were identified retrospectively as having had one episode of NSVT during 24‐hour Holter ECG recording.Methods: We measured the mean interval between normal beats (meanRR), the standard deviation of the intervals between beats (SD), the percentage of counts of sequential intervals between normal beats with a change of >50 ms (%RR50), the logarithms of low‐ and high‐frequency spectral components (InLF, InHF) of HRV for sequential 10‐minute segments preceding NSVT. The correlation dimension (CDim) of HRV was calculated similarly for sequential 20‐minute segments. We assessed the significance of the time‐course change of each marker over the 120‐minute period prior to NSVT onset.Results: MeanRR (P < 0.05), InLF (P < 0.0001), InHF (P < 0.0001), the natural logarithm of the ratio of LF to HF (ln[LF/HF]; P < 0.05), and CDim (P < 0.05) showed significant time‐course changes during that period, while SD and %RR50 did not. MeanRR, InLF, InHF, and CDim all decreased prior to the onset of NSVT, whereas ln(LF/HF) increased. We divided the subjects into two groups: one consisting of 12 patients with coronary artery disease; and the second group of 12 patients without known coronary artery disease. Both groups showed significant changes (P < 0.05) of CDim, InLF, and InHF preceding the episodes of NSVT.Conclusions: Changes in the pattern of HRV prior to the onset of episodes of NSVT suggest that changes in autonomic activity may commonly play a role in the triggering of spontaneous episodes of NSVT in susceptible patients. The measured changes suggest a reduction in parasympathetic activity, perhaps in conjunction with an increase in sympathetic activity, may trigger NSVT.
Electrocardiographic Self‐Recording (Patient‐Activated Event Recording)
Authors: Steinbach Konrad , Nümberg Michael , Wessely Emil 
Published: October 2006

Background: Although symptoms suggestive of cardiac arrhythmias are a common event in clinical routine, a standardized diagnostic approach is not available.Methods: The diagnostic accuracy of electrocardiographic self‐recording was evaluated in 115 consecutive patients presenting with symptoms suggestive of cardiac arrhythmias.Results: In 44.3% of cases, self‐recording showed cardiac arrhythmias to be the cause of the patients' symptoms; in 35.7% cardiac arrhythmias were ruled out as the cause of the patients' symptoms. Only 6.2% of the recordings were not evaluable for technical reasons.Conclusion: ECG self‐recording is more effective in detecting arrhythmias than other methods for arrhythmia monitoring. Therefore, it should be used as a first line study in patients likely to have symptomatic arrhythmias.
Spectral Analysis of the High Resolution QRS Complex During Exercise‐Induced Ischemia
Authors: Beker Amir , Erel Jacob , Pinchas Abraham , Abboud Shimon 
Published: October 2006

Background: The effect of acute myocardial infarction and regional ischemia on the frequency content of the ECG signal has been described by several investigators. In the present study, the feasibility of assessing changes in the QRS spectrum during exercise testing, and whether these changes are related to the occurrence of ischemia were examined.Methods: Spectral analysis of the high resolution ECGs from leads V3, V4, V5, and V6 were performed in two groups of male subjects before, during, and following treadmill exercise testing. Group A included 32 coronary artery disease (CAD) patients, with arteriographically proven >75% obstruction of at least two main coronary arteries, and group B included 30 healthy subjects, without history or symptoms of CAD. Signal averaging and filtering techniques were used in order to enhance the signal‐to‐noise ratio of the recorded ECGs. The power spectrum of the averaged QRS waveform for the different stages of the exercise testing was computed using a Fast Fourier Transform, and the slope of the linear regression line was found in the frequency range 7.81–249.92 Hz on the plot of log((amplitude)2) versus log(frequency).Results: Regression line slopes immediately after peak exercise were significantly lower for the CAD group than for the healthy subjects in 3 of the 4 examined leads. No significant changes in slopes were found between the two groups at rest or during late recovery. Comparing the differences between slopes at different stages of the test revealed that the difference between postexercise slope and rest slope has lower mean values for the CAD group in all four leads, with a significant difference in lead V6, and for the difference between postexercise slope and recovery slope, lower mean values were found for the CAD group in all four leads, with a significant difference in V5 and V6.Conclusions: These findings indicate that ischemic changes affect the power spectrum of the QRS complex, and result in a steeper regression line on a log‐log scale.
Beneficial Effects of Captopril and Metoprolol Treatment in Idiopathic Dilated Cardiomyopathy
Authors: Tomita Fumishi , Kohya Tetsuro , Kaji Tohru , Tsuzuki Noriko , Ono Tomohide , Itoh Yoshinori , Sasaki Motoi , Kitabatake Akira 
Published: October 2006

Background: Abnormal autonomic nervous function (ANF), such as an enhanced sympathetic tone and an attenuated parasympathetic tone, have been shown in patients with congestive heart failure (CHF).Methods: We examined the effects of captopril and metoprolol on autonomic nervous function and ventricular arrhythmias in patients with idiopathic dilated cardiomyopathy (DCM), using 24‐hour ambulatory electrocardiographic monitoring and power spectral analysis of heart rate variability. Twenty‐one patients (pts) with idiopathic DCM (54 ± 15 years [mean ± SDI) were allocated to three groups: a captopril group (8 pts); a metoprolol group (7 pts); and a control group (6 pts). Power spectra were quantified in high (HF) and low frequency power (LF), and natural logarithmic values of HF (In(HF) and LF/HF (In (LF(HF]) were used as indices of parasympathetic and sympathetic nervous activities, respectively.Results: In the captopril and the metoprolol groups, there was a significant increase in In(HF) (P < 0.05), a trend of decrease in ln(LF/HF), and an improvement of ventricular arrhythmia (VA). In contrast, no significant change was found in any of In(HF), In (LF/HF), and VA in the control group.Conclusion: We conclude that both captopril and metoprolol have beneficial effects on ANF and VA, and the restored autonomic balance and the improvement of VA correlate to each other.
Disturbed Autonomic Activity Precedes Ischemic Episodes in Patients with Variant Angina
Authors: Kubota Naokuni , Lee Jong‐Dae , Shimizu Hiromasa , Tsubokawa Akiyoshi , Ueda Takanori 
Published: October 2006

BackgroundWhile the autonomic nervous system is known to be involved in the pathogenesis of variant angina, the relationship between disturbed autonomic activity and ischemic episodes in patients with variant angina has not been determined.MethodsWe performed 24‐hour Holter monitoring and power spectral analysis of heart rate variability (HRV) in ten patients with variant angina. The low frequency (0.04–0.15 Hz [LF]) and high frequency (0.15–0.40 Hz [HF]) components of HRV were quantified. The ratio of LF to HF (LF/HF) and the coefficient of the RR interval variation (CV) were also calculated. We analyzed HRV every 10 minutes beginning 50 minutes before the onset of ischemic episodes confirmed by ST segment elevation.ResultsThe LF/HF from 40 to 30 minutes before ischemia was decreased compared with the value from 50 to 40 minutes before ischemia (0.80 ± 0.15 vs 1.63 ± 0.44, mean ± SE, P = 0.037). The LF/HF then began to increase, and the value from 20 to 10 minutes (2.91 ± 0.66) was significantly greater than that from 40 to 30 minutes (P < 0.01). The CV was increased from 30 to 20 minutes before ischemia compared with the CV from 50 to 40 minutes (8.5%± 1.6% vs 5.2%± 0.8%, P = 0.033). The LF/HF and the CV remained increased until the onset of ischemia.ConclusionsData suggests that a disturbed autonomic nervous activity plays an important role in the initiation of coronary vasospasm in patients with variant angina. A.N.E. 1997;2(4):313–318
The Outcome of Exercise Tolerance Testing is Dependent on the Time of the Day
Authors: de Vries Rob J. M. , Witting Wil , van Veldhuisen Dirk J. , de Kam Pieter J. , Crijns Harry J.G.M. 
Published: October 2006

BackgroundAlthough exercise testing is commonly used to identify patients with an increased risk for ischemic events and to evaluate drug therapy, no reports have clearly addressed whether a daily variation exists in exercise test parameters. Therefore the present study was undertaken, analyzing the effects of the time of the day on exercise test parameters in a large population of cardiovascular patients.MethodsWe compared the responses of bicycle exercise testing in 6674 patients, mean age 60 years, referred for evaluation of coronary artery disease. The daily variation was tested by grouping the exercise variables into four 2‐hour periods. Further logistic regression analysis was used to assess predictors for the occurrence of ischemia.ResultsSignificant time of the day differences were found both at rest and in their changes to peak exercise for heart rate (P < 0.0001 and P < 0.0004), systolic blood pressure (P < 0.0001 and P < 0.0003), and diastolic blood pressure (P < 0.004 and P < 0.0001). Furthermore, ischemia occurred significantly more often during the afternoon intervals (P < 0.009) and time of the day was an independent predictor of ischemia during exercise testing.ConclusionThe present study demonstrates that several exercise parameters show a significant daytime variation. The time of the day is an independent predictor for the occurrence of ischemia during an exercise test, and the detection of ischemia may be enhanced by performing exercise tests in the afternoon.
Heart Rate Variability Early After Successful Radiofrequency Catheter Ablation of Left‐ and Right‐Sided Accessory Pathways and After Selective Ablation of the Slow Pathway
Authors: Sztajzel Juan M. , Vinolas Xavier , Sobral José , Dumaresq Lucia , Boveda Serge , Torner Pelayo , Oter Ramon , de Luna Antonio Bayés 
Published: October 2006

BackgroundInappropriate sinus tachycardia (1ST) and alterations in heart rate variability (HRV) may survene after radiofrequency catheter ablation (RFCA). The objective of this study was to analyze and to compare HRV after RFCA of supraventricular tachycardia.MethodsHRV components were analyzed and compared in 86 patients early after successful RFCA of left‐sided (LSAP) (n = 38) and right‐sided (RSAP) accessory pathways (n = 18), and after selective ablation of the slow atrioventricular nodal pathway (n = 30). All HRV parameters, including indices of time‐domain, 24‐hour RR histogram, and power spectral analysis, were obtained from Holler tapes recorded 24–48 hours after RFCA, free of antiarrhythmic drugs.ResultsWe found a significant increase in mean heart rate and significant reductions in most indices of time domain in patients of the slow pathway >SP) group when comparing to the two other groups. 1ST was found in 7% of patients. The plot of the 24‐hour RR histogram and the frequency‐domain analysis, demonstrated the same tendency to significantly lower values in patients of the SP group. Values of r‐MSSD and pNN5O were significantly reduced in patients of the RSAP group, most (72%) of posteroseptal (PS) location, in comparison with values observed in patients of the LSAP group.ConclusionsIn our study, comparisons between postablation HRV indices of the three groups suggest a decrease of the sympathetic and parasympathetic components in patients of the SP group, probably due to autonomous fiber damage. Ablation in patients of the RSAP group, most of PS location, shows an attenuation of the predominantly parasympathetic component, probably in relation to the anatomical site of the PS pathways, and indicates thereby an intermediate behavior of this type of pathway.
Incidence and Clinical Significance of Ventricular Late Potentials in Idiopathic Dilated Cardiomyopathy Compared to Coronary Artery Disease
Authors: Grimm Wolfram , Winzenburg Jens , Knop Ursula , Hoffmann Jürgen , Menz Volker , Grote Frank , Maisch Bernhard 
Published: October 2006

Objective: This prospective study was designed to compare incidence and clinical significance of ventricular late potentials between patients with idiopathic dilated cardiomyopathy (IDC) and postinfarct patients (CAD) using exactly the same method of signal‐averaged electrocardiography (SAECG) in both patient groups.Methods: Time‐domain analysis of SAECG was performed in 120 consecutive patients with IDC, 120 patients with CAD, and 60 healthy controls. Ventricular late potentials were detected in 27 of 120 patients with IDC (23%) compared to 41 of 120 patients with CAD (34%; P < 0.05).Results: Ventricular late potentials were found in 2 of 60 controls (3%). During 15 ± 7 months follow‐up, serious arrhythmic events occurred in 17 of 120 patients with IDC (14%) and in 13 of 120 patients with CAD (11%). The sensitivity of ventricular late potentials for future arrhythmic events was 35% for IDC compared to 77% for CAD (P < 0.05). The positive predictive value of late potentials detected by time‐domain analysis was 22% for IDC versus 24% for CAD (P = ns).Conclusion: In this selected patient population with IDC and CAD, time‐domain analysis of SAECG revealed a lower incidence of ventricular ate potentials in patients with IDC as compared to postinfarct patients. Whereas ventricular late potentials had a high sensitivity but a low positive predictive value for identification of postinfarct patients with serious arrhythmic events during follow‐up, both sensitivity and positive predictive value of ventricular late potentials for future serious arrhythmic events were low in the setting of IDC.