bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppressive subtractive hybridization as a tool for identifying genetic diversity in an environmental metagenome: the rumen as a model
Authors: Galbraith Elizabeth A. , Antonopoulos Dionysios A. , White Bryan A.
Published: August 2004

Molecular techniques previously used for genome comparisons of closely related bacterial species could prove extremely valuable for comparisons of complex microbial communities, or metagenomes. Our study aimed to determine the breadth and value of suppressive subtractive hybridization (SSH) in a pilot‐scale analysis of metagenomic DNA from communities of microorganisms in the rumen. Suppressive subtractive hybridization was performed using total genomic DNA isolated from rumen fluid samples of two hay‐fed steers, arbitrarily designated as tester or driver. Ninety‐six subtraction DNA fragments from the tester metagenome were amplified, cloned and the DNA sequences were determined. Verification of the isolation of DNA fragments unique to the tester metagenome was accomplished through dot blot and Southern blot hybridizations. Tester‐specific SSH fragments were found in 95 of 96 randomly selected clones. DNA sequences of subtraction fragments were analysed by computer assisted DNA and amino acid comparisons. Putative translations of 26 (32.1%) subtractive hybridization fragments exhibited significant similarity to Bacterial proteins, whereas 15 (18.5%) distinctive subtracted fragments had significant similarity to proteins from Archaea. The remainder of the subtractive hybridization fragments displayed no similarity to GenBank sequences. This metagenomic approach has exposed an unexpectedly large difference in Archaeal community structure between the rumen microbial populations of two steers fed identical diets and housed together. 16S rRNA dot blot hybridizations revealed similar proportions of Bacteria and Archaea in both rumen samples and suggest that the differences uncovered by SSH are the result of varying community structural composition. Our study demonstrates a novel approach to comparative analyses of environmental microbial communities through the use of SSH.
Application of tetranucleotide frequencies for the assignment of genomic fragments
Authors: Teeling Hanno , Meyerdierks Anke , Bauer Margarete , Amann Rudolf , Glöckner Frank Oliver
Published: August 2004

A basic problem of the metagenomic approach in microbial ecology is the assignment of genomic fragments to a certain species or taxonomic group, when suitable marker genes are absent. Currently, the (G +  C)‐content together with phylogenetic information and codon adaptation for functional genes is mostly used to assess the relationship of different fragments. These methods, however, can produce ambiguous results. In order to evaluate sequence‐based methods for fragment identification, we extensively compared (G + C)‐contents and tetranucleotide usage patterns of 9054 fosmid‐sized genomic fragments generated in silico from 118 completely sequenced bacterial genomes (40 982 931 fragment pairs were compared in total). The results of this systematic study show that the discriminatory power of correlations of tetranucleotide‐derived z‐scores is by far superior to that of differences in (G + C)‐content and provides reasonable assignment probabilities when applied to metagenome libraries of small diversity. Using six fully sequenced fosmid inserts from a metagenomic analysis of microbial consortia mediating the anaerobic oxidation of methane (AOM), we demonstrate that discrimination based on tetranucleotide‐derived z‐score correlations was consistent with corresponding data from 16S ribosomal RNA sequence analysis and allowed us to discriminate between fosmid inserts that were indistinguishable with respect to their (G + C)‐contents.
Construction, characterization, and use of small‐insert gene banks of DNA isolated from soil and enrichment cultures for the recovery of novel amidases
Authors: Gabor Esther M. , De Vries Erik J. , Janssen Dick B.
Published: August 2004

To obtain new amidases of biocatalytic relevance, we used microorganisms indigenous to different types of soil and sediment as a source of DNA for the construction of environmental gene banks, following two different strategies. In one case, DNA was isolated from soil without preceding cultivation to preserve a high degree of (phylo)genetic diversity. Alternatively, DNA samples were obtained from enrichment cultures, which is thought to reduce the number of clones required to find a target enzyme. To selectively sustain the growth of organisms exhibiting amidase activity, cultures were supplied with a single amide or a mixture of different aromatic and non‐aromatic acetamide and glycine amide derivatives as the only nitrogen source. Metagenomic DNA was cloned into a high‐copy plasmid vector and transferred to E. coli, and the resulting gene banks were searched for positives by growth selection. In this way, we isolated a number of recombinant E. coli strains with a stable phenotype, each expressing an amidase with a distinct substrate profile. One of these clones was found to produce a new and highly active penicillin amidase, a promising biocatalyst that may allow higher yields in the enzymatic synthesis of β‐lactam antibiotics.
Analysis of a genome fragment of a deep‐sea uncultivated Group II euryarchaeote containing 16S rDNA, a spectinomycin‐like operon and several energy metabolism genes
Authors: Moreira David , Rodríguez‐Valera Francisco , López‐García Purificación
Published: August 2004

We have sequenced and analysed a 39.5 kbp genome fragment of a marine Group II euryarchaeote identified in a metagenomic library of 500 m deep plankton at the Antarctic Polar Front. The clone contains a 16S rRNA gene that is separated from the 23S rRNA gene in the genome. This appears to be a trait shared by Thermoplasmatales and Group II euryarchaeota. This genome fragment exhibits a compact organization, including a few overlapping genes in the canonical spectinomycin‐like (spc) operon for ribosomal proteins that is immediately upstream the 16S rDNA. Most open reading frames (ORFs) encoded proteins involved in housekeeping processes and, as expected, exhibited a phylogenetic distribution congruent with that of the 16S rRNA. A considerable number of proteins with predicted transmembrane helices was identified. Among those, two proteins encoded by genes likely forming an operon appear to be part of a membrane terminal electron transport chain. One of these proteins has an unusual domain arrangement including ferredoxin, flavodoxin and one succinate dehydrogenase/fumarate reductase subunit. These proteins probably constitute a new succinate dehydrogenase‐like oxidoreductase involved in what could be a novel pathway for energy metabolism in Group II euryarchaeota.
Characterization of large‐insert DNA libraries from soil for environmental genomic studies of Archaea
Authors: Treusch Alexander H. , Kletzin Arnulf , Raddatz Guenter , Ochsenreiter Torsten , Quaiser Achim , Meurer Guido , Schuster Stephan C. , Schleper Christa
Published: August 2004

Complex genomic libraries are increasingly being used to retrieve complete genes, operons or large genomic fragments directly from environmental samples, without the need to cultivate the respective microorganisms. We report on the construction of three large‐insert fosmid libraries in total covering 3 Gbp of community DNA from two different soil samples, a sandy ecosystem and a mixed forest soil. In a fosmid end sequencing approach including 5376 sequence tags of ≈ 700 bp length, we show that mostly bacterial and, to a much lesser extent, archaeal and eukaryotic genome fragments (≈ 1% each) have been captured in our libraries. The diversity of putative protein‐encoding genes, as reflected by their distribution into different COG clusters, was comparable to that encoded in complete genomes of cultivated microorganisms. A huge variety of genomic fragments has been captured in our libraries, as seen by comparison with sequences in the public databases and by the large variation in G+C contents. We dissect differences between the libraries, which relate to the different ecosystems analysed and to biases introduced by different DNA preparations. Furthermore, a range of taxonomic marker genes (other than 16S rRNA) has been identified that allows the assignment of genome fragments to specific lineages. The complete sequences of two genome fragments identified as being affiliated with Archaea, based on a gene encoding a CDC48 homologue and a thermosome subunit, respectively, are presented and discussed. We thereby extend the genomic information of uncultivated crenarchaeota from soil and offer hints to specific metabolic traits present in this group.
Uncultured soil bacteria are a reservoir of new antibiotic resistance genes
Authors: Riesenfeld Christian S. , Goodman Robert M. , Handelsman Jo
Published: August 2004

Antibiotic resistance genes are typically isolated by cloning from cultured bacteria or by polymerase chain reaction (PCR) amplification from environmental samples. These methods do not access the potential reservoir of undiscovered antibiotic resistance genes harboured by soil bacteria because most soil bacteria are not cultured readily, and PCR detection of antibiotic resistance genes depends on primers that are based on known genes. To explore this reservoir, we isolated DNA directly from soil samples, cloned the DNA and selected for clones that expressed antibiotic resistance in Escherichia coli. We constructed four libraries that collectively contain 4.1 gigabases of cloned soil DNA. From these and two previously reported libraries, we identified nine clones expressing resistance to aminoglycoside antibiotics and one expressing tetracycline resistance. Based on the predicted amino acid sequences of the resistance genes, the resistance mechanisms include efflux of tetracycline and inactivation of aminoglycoside antibiotics by phosphorylation and acetylation. With one exception, all the sequences are considerably different from previously reported sequences. The results indicate that soil bacteria are a reservoir of antibiotic resistance genes with greater genetic diversity than previously accounted for, and that the diversity can be surveyed by a culture‐independent method.
The genome of Desulfotalea psychrophila, a sulfate‐reducing bacterium from permanently cold Arctic sediments
Authors: Rabus R. , Ruepp A. , Frickey T. , Rattei T. , Fartmann B. , Stark M. , Bauer M. , Zibat A. , Lombardot T. , Becker I. , Amann J. , Gellner K. , Teeling H. , Leuschner W. D. , Glöckner F.‐O. , Lupas A. N. , Amann R. , Klenk H.‐P.
Published: August 2004

Desulfotalea psychrophila is a marine sulfate‐reducing δ‐proteobacterium that is able to grow at in situ temperatures below 0°C. As abundant members of the microbial community in permanently cold marine sediments, D. psychrophila‐like bacteria contribute  to  the  global  cycles  of  carbon  and sulfur. Here, we describe the genome sequence of D. psychrophila strain LSv54, which consists of a 3 523 383 bp circular chromosome with 3118 predicted genes and two plasmids of 121 586 bp and 14 663 bp. Analysis of the genome gave insight into the metabolic properties of the organism, e.g. the presence of TRAP‐T systems as a major route for the uptake of C4‐dicarboxylates, the unexpected presence of genes from the TCA cycle, a TAT secretion system, the lack of a β‐oxidation complex and typical Desulfovibrio cytochromes, such as c553, c3 and ncc. D. psychrophila encodes more than 30 two‐component regulatory  systems,  including  a  new  Ntr  subcluster of hybrid kinases, nine putative cold shock proteins and nine potentially cold shock‐inducible proteins. A comparison of D. psychrophila's genome features with those of the only other published genome from a sulfate reducer, the hyperthermophilic archaeon Archaeoglobus fulgidus, revealed many striking differences, but only a few shared features.
Different SAR86 subgroups harbour divergent proteorhodopsins
Authors: Sabehi Gazalah , Béjà Oded , Suzuki Marcelino T. , Preston Christina M. , DeLong Edward F.
Published: August 2004

Proteorhodopsins (PRs), bacterial photoactive proton pumps, were originally detected in the uncultured marine γ‐proteobacterial SAR86 group. PRs are now known to occur in both the γ and α marine proteobacterial lineages. Recent environmental shotgun sequence analysis in the Sargasso Sea has added yet more diversity, and a potentially broader taxonomic distribution, to the PR family. Much remains to be learned, however, about within‐taxon PR variability and the broader organismal distribution of different PR types. We report here genomic analyses of large genome fragments from different subgroups of the SAR86 lineage, recovered from naturally occurring bacterioplankton populations in coastal Red Sea and open ocean Pacific waters. Sequence comparisons were performed on large bacterial artificial chromosomes (BACs) bearing both rRNA and PR genes, derived from different SAR86 subgroups. Our analyses indicated the presence of different PR sequence types within the same SAR86 rRNA subgroup. The data suggested that the distribution of particular PR types does not necessarily parallel the phylogenetic relationship inferred from highly conserved genes such as rRNA. Further analyses of the genomic regions flanking PR also revealed a potential pathway for the biosynthesis of retinal, the PR chromophore that is required to generate the functionally active photoprotein. Finally, comparison of our results with recently reported Sargasso Sea environmental shotgun sequence assemblies demonstrated the utility of BAC clones for interpreting environmental shotgun sequence data, much of which is represented in short contigs that have an overall low depth of coverage.
The application of two‐dimensional polyacrylamide gel electrophoresis and downstream analyses to a mixed community of prokaryotic microorganisms
Authors: Wilmes Paul , Bond Philip L.
Published: August 2004

In the post‐genomic era, the focus of numerous researchers has moved to studying the functional products of gene expression. In microbiology, these ‘omic’ approaches have largely been limited to pure cultures of microorganisms. Consequently, they do not provide information on gene expression in a complex mixture of microorganisms as found in the environment. Our method enabled the successful extraction and purification of the entire proteome from a laboratory‐scale activated sludge system optimized for enhanced biological phosphorus removal, its separation by two‐dimensional polyacrylamide gel electrophoresis and the mapping of this metaproteome. Highly expressed protein spots were excised and identified using quadrupole time‐of‐flight mass spectrometry with de novo peptide sequencing. The proteins isolated were putatively identified as an outer membrane protein (porin), an acetyl coenzyme A acetyltransferase and a protein component of an ABC‐type branched‐chain amino acid transport system. These proteins possibly stem from the dominant and uncultured Rhodocyclus‐type polyphosphate‐accumulating organism in the activated sludge. We propose the term ‘metaproteomics’ for the large‐scale characterization of the entire protein complement of environmental microbiota at a given point in time.
Desistance‐Focused Criminal Justice Policy Research: Introduction to a Special Issue on Desistance from Crime and Public Policy
Authors: Farrall Stephen , Maruna Shadd
Published: August 2004

Abstract: From a very small base of empirical studies in the 1940s and 1950s, the literature on how and why people stop offending has grown rapidly in the last two decades (see Laub and Sampson (2001) for a comprehensive review). Only recently, however, have researchers started to forge links between studies of desistance from crime and ‘What Works’ in offender management policy (see especially, Maruna and Immarigeon 2004). This ‘coming together’ of research into why people stop offending and the (re‐)emergence of concerns with effective practice is, like many partnerships, partly the result of good timing, partly the result of fortune, and not without its tensions and struggles. The purpose of this introductory essay, and indeed of this special issue, is to explore these tensions in greater depth than has been possible in previous work.
Towards Desistance: Theoretical Underpinnings for an Empirical Study
Authors: Bottoms Anthony , Shapland Joanna , Costello Andrew , Holmes Deborah , Muir Grant
Published: August 2004

Abstract: This article presents the initial theoretical underpinnings for a fresh prospective study of desistance, focused on 20‐year‐old recidivists. It is argued that significant crime‐free gaps appropriately form part of the subject matter of desistance. An interactive theoretical framework is presented, involving ‘programmed potential’, ‘social context’ (structures, culture, situations) and ‘agency’. It is argued that agency, while rightly attracting increasing interest within criminology, needs to be used with greater precision. Aspects of the social context of the research subjects' lives are summarised, with special reference to their age‐transitional status and the relevance of ‘community’ in their lives. Since most criminal careers, even of recidivists, are short, the implications of subjects' movement from conformity to criminality and back to conformity require greater thought among criminologists and criminal justice professionals. However, these broad movements contain significant oscillations, and ‘crime’ is not a unidimensional concept in the lives of the research subjects. Capturing and explaining the complexity of these matters longitudinally is a significant challenge for the research.
So ‘Prison Works’, Does It? The Criminal Careers of 130 Men Released from Prison under Home Secretary, Michael Howard
Authors: Burnett Ros , Maruna Shadd
Published: August 2004

Abstract: A 1992 study, The Dynamics of Recidivism, was cited by the Home Secretary of the Conservative government during the 1990s to support the political doctrine that ‘prison works’. This claim drew on qualitative data from pre‐ and post‐prison interviews of 130 male offenders to uphold a narrow rational choice perspective that emphasised the perceived ‘costs’ of imprisonment to the offender. A ten‐year reconviction study was carried out as a follow‐up to the 1992 study. The subsequent criminal careers of the majority of the sample contradict an assumption that imprisonment has a deterrent impact. In the light of these findings, and an analysis of the differential impacts of subjective and social factors in the experiences of these ex‐prisoners, this article reviews the limitations of ‘rational choice theory’ as a basis for understanding recidivism and desistance from crime.
Scripts for Safer Survival: Pathways Out of Female Crime
Authors: Rumgay Judith
Published: August 2004

Abstract: The author explores some theoretical perspectives that, together, might aid development of a heuristic understanding of female desistance from crime: opportunity; identity; scripts; self‐efficacy; and resilience. For an opportunity for desistance to be seized, it must not only present itself to the offender, but also be both recognised and valued as such. It is suggested that successful desistance from crime may be rooted in recognition of an opportunity to claim an alternative, desired and socially approved personal identity. Certain common identities that may present themselves as available (for example, mother) may also provide a ‘script’ by which to enact a conventional, pro‐social social role. Accessibility of such a skeleton script enhances confidence in the ability to enact it successfully, thus altering the woman's sense of self‐efficacy. Studies of resilience and coping further illuminate the skills and strategies that may be utilised to protect and perpetuate a newly acquired self‐identity. The author concludes by drawing some implications for rehabilitation efforts based on such an understanding of female desistance.
Desistance, Rehabilitation and Correctionalism: Developments and Prospects in Scotland
Authors: McNeill Fergus
Published: August 2004

Abstract: This article argues that desistance research should provoke a reconsideration of the essential character of interventions with adults involved in offending behaviour. It begins by discussing broad accounts of the characteristics of late‐modern penal systems as the background to an exploration of current developments in probation policy and practice. In particular, the discussion develops some contrasts between ‘welfarist rehabilitation’ and ‘correctional treatment’ as competing (but inadequate) paradigms for probation practice. In the context of these contrasts, the situation of criminal justice social work in post‐devolution Scotland receives particular attention. Possible implications for practice of some important desistance studies are then developed, in order to stimulate discussion and debate about the extent to which desistance research might challenge the correctionalism that is emerging in probation policy and practice in the UK. In the conclusion, bearing in mind proposed organisational changes on both sides of the border that might tend towards advancing correctionalism, the prospects for more constructive developments in Scotland are considered in the light of emerging evidence about the views of frontline workers and in the light of existing ‘official’ objectives for criminal justice social work.
Roadside Revegetation in Glacier National Park, U.S.A.: Effects of Herbicide and Seeding Treatments
Authors: Tyser Robin W. , Asebrook Jennifer M. , Potter Rachel W. , Kurth Laurie L.
Published: August 2004

From 1992 to 1995 we experimentally evaluated the effectiveness of several revegetation treatments along a segment of Going‐to‐the‐Sun Highway in Glacier National Park, U.S.A. This segment, reconstructed during the spring and summer of 1992, is bordered by fescue prairie vegetation and is known to be susceptible to invasion by several alien species, including Centaurea maculosa (spotted knapweed) and Phleum pratense (common timothy). We used a split plot study design to evaluate the effectiveness of herbicide and seeding treatments on assisting recovery of native flora and limiting the establishment of alien species. The herbicide treatment consisted of a yearly herbicide spray application of clopyralid (3,6‐dichloropicolinic acid). Five seeding treatments were evaluated, three of which included an indigenous graminoid‐forb seed mix. Percent canopy coverages of four species groups—alien graminoids, native graminoids, alien forbs, and native forbs—were determined in July 1995. In addition, community‐level patterns in sprayed plots and unsprayed plots were compared with a reference site of native fescue prairie. Herbicide treatments decreased mean canopy coverage of alien forbs (treated = 4.2%, untreated = 23.4%) and increased mean canopy coverage of native graminoids slightly (treated = 6.3%, untreated = 4.0%). But herbicide treatments reduced mean coverage of native forbs (treated = 3.9%, untreated = 8.9%) and likely increased coverage of alien graminoids. Treatments that included a fall 1992 seed mix increased native graminoid coverages 2.8–4.6 times, although coverages were still lower than those attained by alien graminoids. Native and alien forb coverage appeared unaffected by seeding treatments. Species composition was less diverse in sprayed plots and more dominated by alien grasses than in unsprayed plots and the reference site. Areas for additional study are suggested, including seed bank assays to determine treatment effects on recruitment of alien versus native species and the use of native graminoids to create low‐diversity communities with high canopy coverages to resist establishment of alien species.
A comparison of 3 alloy surface treatments for resin‐bonded prostheses
Authors: Petrie Cynthia S. , Eick J. David , Williams Karen , Spencer Paulette
Published: August 2004

Purpose The most frequent cause of clinical failure of resin‐bonded fixed partial dentures is a debonding at the metal‐cement interface. The purpose of this in vitro study was to compare the tensile bond strengths of 3 different alloy‐surface treatments when cemented to human enamel with a resin cement.

Materials and Methods Cylinders of a nickel‐chromium‐beryllium (Ni‐Cr‐Be) and a gold‐palladium (Au‐Pd) alloy were fabricated and assigned to different surface treatment groups as follows: Group 1: Ni‐Cr‐Be, chemically etched; Group 2: Au‐Pd, airborne particle–abraded and tin‐plated; and Group 3: Au‐Pd, airborne particle–abraded and treated with the Alloy Primer (Kuraray Co, LTD, Osaka, Japan). The cylinders were bonded to the enamel surfaces of extracted, human third molars and stored in normal saline at 37°C for 48 hours. The tensile bond strength of 21 specimens from each group was measured on a Universal Testing Machine (Instron, Canton, MA). Three failed specimens of each group were evaluated using scanning electron microscopy and energy dispersive spectroscopy.

Results Statistically significant differences (p < .05) were found between all 3 treatment groups. The mean tensile bond strengths (± the standard error of mean) recorded as follows: Group 1: 10.6 MPa (±1.3), Group 2: 0.9 MPa (±0.2), and Group 3: 13.4 MPa (±1.0). Specimens from groups 1 and 3 revealed a trend towards mixture of cohesive, within the resin cement, and adhesive failures at the metal‐cement interface. Group 2 specimens exhibited primarily adhesive failures at the metal‐cement interface.

Conclusion The tensile bond strength of Au‐Pd alloy specimens was significantly increased with the Alloy Primer.
Fabricating a provisional restoration for a 2‐stage, single‐tooth implant with less than optimal angulation
Authors: Maalhagh‐Fard Ahmad , Badr Sherif
Published: August 2004

A technique is presented for fabricating a provisional restoration for a buccally angulated implant. This technique describes the fabrication of a provisional restoration for a labially angulated implant. This technique helps the prosthodontists to achieve esthetics and soft‐tissue health until the definitive restoration is available.
The history and development of the dental surveyor: Part I
Authors: Engelmeier Robert L.
Published: August 2004

The dental surveyor is an indispensable instrument capable of performing a number of prosthodontic procedures. Surprisingly, the technique of surveying casts as part of the treatment planning procedure did not emerge until early in the twentieth century. This article reviews the origins and early use of the dental surveyor. It includes features common to all surveyors as well as the principal uses of these instruments.
In vitro examination of the fracture strength of 3 different fiber‐reinforced composite and 1 all‐ceramic posterior inlay fixed partial denture systems
Authors: Kolbeck Carola , Rosentritt Martin , Behr Michael , Lang Reinhold , Handel Gerhard
Published: August 2004

Purpose This in vitro study was carried out to examine the fracture strength of metal‐ free posterior inlay fixed partial dentures (IFPDs). The 3‐unit IFPDs were made of either a polyethylene fiber–reinforced composite, 3 glass fiber–reinforced composites, or an all‐ceramic material.

Materials and Methods Eight IFPDs were fabricated of each material in accordance with the manufacturer's instructions and luted to extracted human molars with a dual‐cure adhesive system. The molars were positioned in PMMA resin 10 mm apart mesiodistally. Inlay cavity preparations with enamel finishing lines were used. After thermal cycling and mechanical loading in an artificial oral environment, the cemented IFPDs were mechanically loaded until failure. Visual and radiologic examinations were done out to discern the different forms of fracture. Median and 25%/75% percentile values were calculated. Statistical analysis was performed using the Mann‐Whitney U test and the Kruskal‐Wallis test (p≤0.05).

Results With a median (and 25%/75% percentile) fracture strength of 368 N (234 N/424 N), the FibreKor/Conquest Sculpture showed significantly lower values than the Connect/BelleGlass [898 N (736 N/1033 N)], Vectris/Targis [723 N (692 N/806 N)], Everstick/Sinfony [634 N (532 N/673 N)], and Empress2 [520 N (385 N/706 N)].

Conclusions Assuming maximum chewing forces of ≥500N in posterior areas, all systems showed sufficient fracture strength in most cases and warrant further investigation for potential clinical use.
Significance of Two Potentials for Predicting Successful Catheter Ablation From the Left Sinus of Valsalva for Left Ventricular Epicardial Tachycardia
Authors: TADA HIROSHI , NAITO SHIGETO , ITO SACHIKO , KUROSAKI KENJI , UEDA MAREHIKO , SHINBO GORO , HOSHIZAKI HIROSHI , OSHIMA SHIGERU , TANIGUCHI KOICHI , NOGAMI AKIHIKO
Published: August 2004

The aim of this study was to identify the characteristics of electrograms that may be helpful in predicting successful ablation of idiopathic ventricular tachycardia from the aortic sinus of Valsalva. Data were obtained from 23 patients with symptomatic ventricular tachycardia or premature ventricular contractions (LV‐VT) who underwent RF catheter ablation from the left sinus of Valsalva. Electrograms before and after application of RF energy during sinus rhythm and during LV‐VT were analyzed. Complete elimination of LV‐VT was finally achieved in 21 (91%) patients. The incidence of presystolic potentials preceding the QRS complex of LV‐VT (P1 potential) was 90% for the 21 successful ablation sites, which did not differ from the incidence for the 24 unsuccessful sites (79%; P = 0.5). During sinus rhythm, a potential following the QRS complex (P2 potential) was more often recorded at the successful ablation site than at an unsuccessful ablation site before and after application of RF energy (before, P < 0.05; after, P < 0.001). The appearance of the P2 potential or a delay in the preexisting P2 potential after application of RF energy was observed only at the successful ablation sites (P < 0.001). In 18 control individuals who had no LV‐VT, no P2 potential was recorded within the left sinus of Valsalva. Although the P1 potential may be useful for identifying the successful ablation site, its sensitivity is low. The appearance of the P2 potential or an increasingly delayed P2 potential after application of RF energy may be more useful than the P1 potential for predicting successful ablation.
Magnetoelectroanatomic Mapping of Arrhythmias in Structural Heart Disease Using a Novel Multielectrode Catheter:
Authors: CHAUHAN VIJAY S. , NAIR GIRISH M. , SEVAPTISIDIS ELIAS , DOWNAR EUGENE
Published: August 2004

Electroanatomic mapping with CARTO requires point‐by‐point acquisition using the mapping catheter's bipolar tip electrode. This study evaluates the utility of a novel 26‐electrode catheter (Qwikstar) for electroanatomic mapping of arrhythmias in patients with structural heart disease. The multielectrode catheter acquires activation times and anatomic data simultaneously from its tip and shaft electrodes. Eight patients (6 men, 2 women, age 47 years [37, 65]) with atrial tachycardia (n = 6) and ventricular tachycardia (n = 2) due to congenital heart disease (n = 4) and cardiomyopathy (n = 4) were studied. Using the multielectrode catheter, the electroanatomic map was constructed in two stages: (1) a scout map using the minimum number of tip and shaft electrode data points that covered > 70% of the tachycardia cycle length and/or the majority of the chamber volume, and (2) a complete map using additional tip electrode data points. A total of 36 (28, 510) tip electrode and 38 (34, 42) shaft electrode electroanatomic data points comprised the scout map. The complete map was constructed with a total of 102 (73, 134) tip electrode electroanatomic data points. In three patients, the scout map suggested a cavotricuspid isthmus dependent atrial flutter that was confirmed with the complete map. In another four patients, the scout map identified the earliest site of focal activation, which was also confirmed with the complete map. In comparison, activation mapping using the bipolar catheter (Navistar) in a group of arrhythmia‐matched control subjects required 210 (180, 320) electroanatomic data points (P = 0.012 vs multielectrode catheter complete map). In conclusion, for large macroreentrant or focal arrhythmias in patients with structural heart disease, the multielectrode catheter can generate a scout map that accurately guides complete electroanatomic mapping using fewer point‐by‐point acquisitions than the bipolar catheter.
Short Head‐Up Tilt Test Potentiated with Oral Nitroglycerine:
Authors: NAVA SANTIAGO , MONT LLUÍS , SILVA ROSE M.F.L. , ROGEL ULISES , OSORIO PAULO , BARTHOLOMAY EDUARDO , BERRUEZO ANTONIO , CHUECA ENRIQUE , BRUGADA JOSEP
Published: August 2004

Conventional tilt test protocols are time consuming and there is no consensus regarding the optimal duration of the test and the provocative drug to be used. This study evaluated the diagnostic power of a short nitroglycerine test against a conventional isoproterenol protocol. A cohort of 128 patients with unexplained syncope was studied. A group of 64 consecutive patients were tilted with a short nitroglycerine test consisting of a passive phase of 15 minutes and if this proved negative, 400 μg of sublingual nitroglycerin spray for a further 15 minutes. The control group consisted of 64 patients tilted with a conventional isoproterenol protocol with a passive phase of 30 minutes and a drug‐challenge phase of 20 minutes. In the nitroglycerine protocol 39 (60.9%) patients showed a positive response versus 27(42.2%) in the isoproterenol group (P = 0.034). The duration of the protocol was 23.2 ± 7.2 minutes in the nitroglycerine group versus 41.1 ± 15.5 minutes with isoproterenol (P = 0.001). The time until syncope was 18.87 ± 6.1 versus 29 ± 18, respectively (P = 0.002). For evaluating unexplained syncope the short tilt test protocol with nitroglycerine is less time consuming, easier to perform, and has a higher rate of positive response than a conventional isoproterenol protocol.
Examination of a Middle Cardiac Vein Defibrillation Coil as Stand‐Alone Anode, Auxiliary Anode, and Bystander Electrode in a Transvenous Defibrillation Circuit
Authors: PAISEY JOHN R. , YUE ARTHUR M. , BESSOULE FREDERICK , ALLEN STUART , ROBERTS PAUL R. , MORGAN JOHN M.
Published: August 2004

In porcine studies anodes in the middle cardiac vein compare favorably with those in the RV. It has not been demonstrated whether the RV and middle cardiac vein or the middle cardiac vein alone anodes are superior when shocking to a conventional SVC and active housing cathode nor whether a bystander middle cardiac vein electrode exerts a passive electrode affect. Twelve pigs were anesthetized and had an active housing implanted in the left pectoral region and defibrillation coils placed at the RV apex and in the SVC. A custom‐made defibrillation coil (Ela Medical) was advanced into the middle cardiac vein through a 9 Fr transvenous catheter. The DFT for three anodes (RV; RV and middle cardiac vein; middle cardiac vein) to the SVC and active housing was then assessed by a three reversal binary search, the order of testing was randomized. In seven animals DFT was assessed in the same way for the configuration of RV to SVC and active housing twice more, with and without a bystander middle cardiac vein coil electrode in place. The results were middle cardiac vein 7.5 ± 1.7 J, RV and middle cardiac vein 7.3 ± 1.7 J reduced DFT significantly compared to RV 13.8 ± 4.2 J (both P < 0.000). There was no significant difference between the middle cardiac vein and the middle cardiac vein and RV (P = 0.67, 95% CI for difference − 0.64–0.96). The DFT of RV to SVC and the active housing was the same with (13.2 ± 4.0) and without (13.7 ± 4.2) the middle cardiac vein bystander coil in place (P = 0.177, 95% CI for difference − 0.33–1.33 J). Shocking to a SVC and active housing cathode, middle cardiac vein, and RV and middle cardiac vein anodes are equally effective in lowering DFT compared to the RV. The middle cardiac vein coil electrode does not exert a passive electrode affect on the RV to the SVC and active housing defibrillation.
Alteration of the QT Rate Dependence in Anorexia Nervosa
Authors: ROCHE FRÉDÉRIC , ESTOUR BRUNO , KADEM MYRIAM , MILLOT LUC , PICHOT VINCENT , DUVERNEY DAVID , GASPOZ JEAN‐MICHEL , BARTHÉLÉMY JEAN‐CLAUDE
Published: August 2004

Myocardial repolarization has been evaluated in patients with anorexia nervosa (AN) with conflicting results. The authors postulated that dynamic alterations in QT interval adaptation could characterize these patients. This study compared QT dynamicity along RR intervals from 24‐hour ECG data of patients with and without AN. Twenty‐five patients (23 women) fulfilling the Diagnostic and Statistical Manual (DSM IV) criteria for AN were included in the study. All underwent 24‐hour ECG Holter recordings, allowing QT and RR measurements, and heart rate variability (HRV) analysis in free‐living conditions. A group of 25 sex‐ and age‐matched healthy subjects served as controls. Compared with controls, AN patients presented with relative bradycardia, more particularly during night periods but neither mean QT nor corrected mean QT length (calculated using Bazett formula) over the 24 hours of monitoring differed. However, QT/RR slope was found significantly enhanced compared with normals (− 2.00 ± 0.53 vs − 1.42 ± 0.40) (P = 0.006): QT length related to heart rate was found longer for a heart rate <55 beats/min in AN. Mean 24‐hours QT length appears unaltered in AN in the absence of electrolytic disorders. However, the QT/RR relationship was enhanced reflecting the specific autonomic imbalance encountered in this population. The clinical implications of such findings need to be discussed since an equivalent enhancement of QT/RR slope has been described after myocardial infarction in patients presenting life‐threatening ventricular arrhythmias.
Mechanisms Underlying Sustained Firing From Pulmonary Veins:
Authors: DIXIT SANJAY , GERSTENFELD EDWARD P. , CALLANS DAVID J. , MARCHLINSKI FRANCIS E.
Published: August 2004

Atrial Fibrillation (AF) is often initiated by pulmonary vein (PV) depolarizations. However, sustained PV firing (PVF) is infrequently observed in this population and has not been characterized. In 15 patients undergoing AF ablation we report the response of sustained PVF to pacing and pharmacological maneuvers. Sustained PVF was defined as discrete, repetitive, electrical activity during sinus rhythm that did not correspond with other electrical events (P, QRS, T wave), persisting ≥5 minutes and recorded at/or distal to PV ostium prior to ablation. During sustained PVF, pacing was performed from coronary sinus and/or posterior right atrium at different cycle lengths (900 to 400 ms; duration: 30 to 60 s) following which, if PVF persisted, in random order, isoproterenol and adenosine were administered and carotid sinus massage (CSM) was performed. PVF response was classified as: suppressed (complete quiescence), augmented (increase in frequency of PVF/AF initiation) and “no effect.” Sustained PVF was observed in 16 veins. In 13 (81%) patients, PVF was suppressed during overdrive pacing with early recurrence (≤5 s) postpacing regardless of pacing cycle length in 11 (85%) patients. PVF was augmented by isoproterenol in the majority of patients (88%) and showed mixed response to adenosine (augmented 40%, suppressed 20%, and no effect 40%). CSM appeared to have no effect on PVF in the majority of patients (86%). Sustained PVF is seen infrequently in patients undergoing AF ablation. Its response to pacing maneuvers argues against sustained reentry and supports triggered activity and/or abnormal automaticity as the mechanisms underlying the phenomenon.
Pacemaker Diagnostics to Determine Treatment and Outcome in Sick Sinus Syndrome with Paroxysmal Atrial Fibrillation
Authors: MARSHALL ANDREW J. , NASH ANTONY , OWEN PAUL A.R. , TODD DAVID , JONES DAVID
Published: August 2004

Sequential analysis of pacemaker diagnostics has been used to help manage the treatment and pacemaker program in patients who have sick sinus syndrome with documented paroxysmal atrial fibrillation. One hundred consecutive patients were followed for an average of 18 months. Knowledge of the atrial fibrillation burden led to major changes in medical management for half of the patients and changes to pacemaker programming for all. At the end of the study, 48 patients were free of arrhythmia with pacing although 14 required antiarrhythmic medication. We advocate using pacemaker diagnostics to improve patient management.
Lead Stuck (Frozen) in Header:
Authors: FISHER JOHN D. , LAPMAN PETER , KIM SOO G. , FERRICK KEVIN J. , GROSS JAY N. , PALMA EUGEN C. , DELVECCHIO ALEXANDER
Published: August 2004

It is occasionally difficult to disconnect leads from headers at the time of pulse generator replacement without injuring the fragile leads. Over a 2.5‐year period we encountered this problem in six cases (1.7% of pulse generator replacements). The posterior portion of the header was clipped off using an orthopedic bone cutter in four cases. The cut was aligned with the deep end of the lead socket in the header. A metal rod was then used to push the lead out of the socket. Bench testing of alternative methods was done on previously explanted pulse generators that were firmly held in a vice. Motorized microtools were used to drill holes from the end of the header to the deep end of the socket; or with a rotary saw attachment to slice off the back of the header, allowing a retained lead to be pushed out. The latter was also done with a hand held razor saw, and attempts were made with a scalpel. Lead removal in the clinical cases was accomplished quickly in the four cases using the bone‐cutter, without trauma to the lead. Bench testing results varied. The bone cutter was the most efficient method for most brands, but was ineffective on one. The motorized tool was difficult to position, produced sprays of plastic particles, and would have been risky in a clinical setting. The razor saw was difficult to use safely, or efficiently, except in some headers that resisted the bone cutter. The scalpel failed except in one “soft header” pacemaker. An orthopedic bone cutter is a useful tool for removing a retained lead from a pulse generator header. Different header designs and materials necessitate knowledge of several lead detachment methods.
Twiddler's Syndrome Detected by Home Monitoring Device
Authors: SCHOLTEN MARCOEN F. , THORNTON ANDREW S. , THEUNS DOMINIC A. , RES JAN , JORDAENS LUC J.
Published: August 2004

Lead fracture due to twiddler's syndrome, was detected in a 68‐year‐old patient 1 month after implantation of an ICD by means of the incorporated home monitoring system. The patient was admitted and the lead replaced. This case illustrates the clinical benefit of the home monitoring system.
Treatment of Sustained Left Atrial Tachycardia by Ostial Pulmonary Vein Isolation
Authors: HERWEG BENGT , ILERCIL ARZU , WHITAKER DAVID M. , HAMILTON LYN , KHAN NADIM G. , BAROLD S. SERGE
Published: August 2004

This report describes two patients with sustained regular left atrial tachycardias originating from multiple pulmonary veins in the absence of clinical evidence of atrial fibrillation. The tachycardias were eliminated by activation map‐guided pulmonary vein isolation. Stable sustained regular pulmonary vein tachycardias unassociated with atrial fibrillation are uncommon, and they belong to the spectrum of pulmonary vein arrhythmias that include the more common paroxysmal and unstable tachycardias engendering atrial fibrillation.
Permanent Left Atrial Electromechanical Dissociation After Conversion of Atrial Fibrillation in a Patient with Interatrial Block
Authors: MATANA ANTE , ZAPUTOVIĆ LUKA , MAVRIĆ ŽARKO , KAŠTELAN ZRINKA MATANA , ROMANO SLOBODAN , ZANINOVIĆ‐JURJEVIĆ TEA
Published: August 2004

In a 52‐year‐old woman, pharmacological conversion to sinus rhythm was achieved after 31 days of atrial fibrillation. In spite of permanent sinus rhythm, even 7 months after the conversion, no mechanical left atrial activity was restored, although right atrium showed normal contractility.
Delayed Detection of Ventricular Tachycardia in a Dual Chamber Rate Adaptive Pacing Implantable Cardioverter Defibrillator:
Authors: SHALABY ALAA A.
Published: August 2004

Ventricular tachycardia detection is delayed due to concomitant programming of rate adaptive dual chamber pacing. Underlying timing cycle constraints as well as programming precautions and pitfalls are reviewed.
Defibrillator for Primary Prevention in Congenital Heart Disease
Authors: SUEBLINVONG VITHIDA , OVADIA MARC
Published: August 2004

A 21‐year‐old patient with repaired double‐outlet right ventricle and normal ventricular function underwent internal cardioverter defibrillator implantation for primary prevention of sudden death. First occurrence of spontaneous ventricular tachycardia resulted in hemodynamic collapse and syncope but the internal cardioverter defibrillator rescued the patient. ICD implantation for primary prevention may be an appropriate goal in adults with repaired congenital heart disease, even in the setting or normal ventricular function.
Successful Selective Ablation of Fast Atrioventricular Node Pathway by Cryothermal Energy Application
Authors: PONTI ROBERTO DE , TRITTO MASSIMO , LANZOTTI MARCELO E. , SPADACINI GIAMMARIO , MARAZZI RAFFAELLA , CARAVATI FABRIZIO , SALERNO‐URIARTE JORGE A.
Published: August 2004

This paper reports the experience of successful cryoablation of fast atrioventricular nodal pathway in a patient with recurrent atrioventricular nodal reentrant tachycardia after previous unsuccessful attempts of slow pathway ablation. Slow formation of a permanent lesion by cryothermal energy application allowed precise modulation of atrioventricular nodal conduction until the endpoints of complete fast pathway ablation were met with long‐term cure of the arrhythmia.
Deterioration in Marital and Family Therapy: Empirical, Clinical, and Conceptual Issues
Authors: GURMAN ALAN S. , KNISKERN DAVID P.
Published: August 2004

Recent empirical evidence of deterioration during both nonbehavioral and behavioral marital and family therapy is presented. While the frequency of patient worsening in marital‐family therapy does not appear to exceed that previously found for individual psychotherapy, the acceptability of the evidence for negative effects in the treatment of systems may be greater than that which exists for individual treatment. After examining the empirical evidence of negative effects in family therapy and some of the factors that influence their occurrence, the authors discuss some conceptual issues relevant to a definition of worsening in marital and family therapy and present some methodological guidelines for the assessment of deterioration in therapy with family systems. It is concluded that the study of deterioration processes in family therapy may aid the understanding of family change processes more generally.
Family Therapy and Drug Abuse: A National Survey
Authors: COLEMAN SANDRA B. , DAVIS DONALD I.
Published: August 2004

The following report describes the results of a national study of the role of family therapy in the drug abuse field. Characteristics of agencies that work with families are described, as well as the demographic characteristics and psychological problems of the clients most apt to be treated in family therapy. The study also looks at the role and structure of family therapy in the ecological system of the treatment institutions. A profile of the family therapists who are responsible for providing services to families is presented. An attempt was made to assess agencies' level of development with regard to family therapy by using an instrument, The Progress Index for Family Therapy Programs. Generally, findings indicated that there is considerable variation in expertise. More extensive training in family therapy techniques was of major concern, particularly among clinics with a heroin addict population.