bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic h‐index: The Hirsch index in function of time
Authors: Egghe Leo
Published: December 2006

When there are a group of articles and the present time is fixed we can determine the unique number h being the number of articles that received h or more citations while the other articles received a number of citations which is not larger than h. In this article, the time dependence of the h‐index is determined. This is important to describe the expected career evolution of a scientist's work or of a journal's production in a fixed year. We use the earlier established cumulative nth citation distribution. We show that

where a is the aging rate, α is the exponent of Lotka's law of the system, and T is the total number of articles in the group. For t = +∞ we refind the steady state (static) formula $h = T^{{1 \over \alpha }}$, which we proved in a previous article. Functional properties of the above formula are proven. Among several results we show (for α, a, T fixed) that h is a concavely increasing function of time, asymptotically bounded by $T^{{1 \over \alpha }}$.
A library or just another information resource? A case study of users' mental models of traditional and digital libraries
Authors: Makri Stephann , Blandford Ann , Gow Jeremy , Rimmer Jon , Warwick Claire , Buchanan George
Published: December 2006

A user's understanding of the libraries they work in, and hence of what they can do in those libraries, is encapsulated in their “mental models” of those libraries. In this article, we present a focused case study of users' mental models of traditional and digital libraries based on observations and interviews with eight participants. It was found that a poor understanding of access restrictions led to risk‐averse behavior, whereas a poor understanding of search algorithms and relevance ranking resulted in trial‐and‐error behavior. This highlights the importance of rich feedback in helping users to construct useful mental models. Although the use of concrete analogies for digital libraries was not widespread, participants used their knowledge of Internet search engines to infer how searching might work in digital libraries. Indeed, most participants did not clearly distinguish between different kinds of digital resource, viewing the electronic library catalogue, abstracting services, digital libraries, and Internet search engines as variants on a theme.
Overcoming knowledge management challenges during ERP implementation: The need to integrate and share different types of knowledge
Authors: Pan Shan L. , Newell Sue , Huang Jimmy , Galliers Robert D.
Published: December 2006

In this article, the author examines an enterprise resource planning (ERP) adoption process in a particular case setting to explore the knowledge management challenges encountered, specifically challenges related to the sharing and integration of knowledge, and the ways that social capital is used to overcome these challenges. More specifically, the author relates the different sources and effects of social capital to the different implementation phases, with their differing knowledge management challenges. By doing so, he highlights the relative importance of the bridging and bonding aspects of social capital that vary during different phases because of the different types of knowledge that become more or less important over the lifecycle of the project—embrained, embodied, encultured, embedded, and encoded.
RhI‐Catalyzed Bimolecular Cyclization between Two Different 1,5‐Bisallenes: A Combinatorial One‐Step Approach to Heterosteroids and Mechanistic Implications
Authors: Ma Shengming , Lu Lianghua
Published: December 2006

In this paper, a bimolecular‐cyclization reaction between two different bis(allene)s with at least one heteroatom as the tether under the catalysis of trans‐[RhCl(CO)(PPh3)2] is described. This protocol provides an efficient entry to different heterocyclic 18,19‐norsteroid‐like scaffolds. The tricyclic product was formed highly selectively from the cyclization reaction of bis(2,3‐butadienyl)sulfide with dimethyl 2‐bis(2′,3′‐butadienyl)malonate, which sheds light on the mechanism involving the metalla‐[4.3.0]‐bicyclic intermediate formed by the cyclometallation of the terminal and the internal C=C bonds of each of the two allene moieties in 2‐bis(2′,3′‐butadienyl)malonate.
Highly Efficient Non‐Palladium‐Catalyzed Controlled Synthesis and X‐ray Analysis of Functionalized 1,2‐Diaryl‐, 1,2,3‐Triaryl‐, and 1,2,3,4‐Tetraarylbenzenes
Authors: Goel Atul , Singh Fateh Veer , Dixit Manish , Verma Deepti , Raghunandan Resmi , Maulik Prakas R.
Published: December 2006

A general, two‐step, highly efficient synthesis of 1,2‐diaryl‐, 1,2,3‐triaryl‐, and 1,2,3,4‐tetraarylbenzenes from simple stitching of α‐oxo‐ketene‐S,S‐acetals and active methylene compounds via a lactone intermediate is described. This procedure offers easy access to highly functionalized arylated benzenes that contain sterically demanding groups in good to excellent yields. The novelty of the procedure lies in the construction of aromatic compounds with the desired conformational flexibility along the molecular axis in a transition‐metal‐free environment through easily accessible precursors. Crystal analysis of these arylated benzene scaffolds showed that the peripheral aryl rings are arranged in a propeller‐like fashion with respect to the central benzene ring. Examination of the crystal packing in the structure of a 1,2,3,4‐tetraarylbenzene revealed an N⋅⋅⋅π interaction between molecules related by a two‐fold screw axis running in the direction of the a axis. Interestingly, the repeating array of N⋅⋅⋅π interactions around the axis of this 1,2,3,4‐tetraarylbenzene forces the molecules into a helical pattern.
Microparticles and nanoparticles for drug delivery
Authors: Kohane Daniel S.
Published: December 2006

Particulate drug delivery systems have become important in experimental pharmaceutics and clinical medicine. The distinction is often made between micro‐ and nanoparticles, being particles with dimensions best described in micrometers and nanometers respectively. That size difference entails real differences at many levels, from formulation to in vivo usage. Here I will discuss those differences and provide examples of applications, for local and systemic drug delivery. I will outline a number of challenges of interest in particulate drug delivery. Biotechnol. Bioeng. 2007;96: 203–209. © 2006 Wiley Periodicals, Inc.
Dynamic modeling of an enzymatic membrane reactor for the treatment of xenobiotic compounds
Authors: López C. , Moreira M.T. , Feijoo G. , Lema J.M.
Published: December 2006

A membrane enzymatic reactor, consisting of a stirred tank coupled to an ultrafiltration membrane was set up for the enzymatic oxidation of xenobiotic compounds. The azo dye Orange II was selected for the model compound and manganese peroxidase for the oxidative enzyme. The ligninolytic cycle was initiated and maintained by the controlled addition of all factors (reactants, mediators, and stabilizers) at suitable rates. Considering the distinctiveness of this process, in which the substrate to be oxidized is not the primary substrate for the enzyme, a kinetic model was developed. The azo dye concentration and hydrogen peroxide addition rate were found to be the main factors affecting the process. The reaction kinetics was defined using a Michaelis–Menten model with respect to the Orange II concentration and a first‐order linear dependence relative to the H2O2 addition rate. The dynamic model, which takes into account both the kinetics and the hydraulics of the system, was validated by comparing the experimental results in continuous operation under steady and non‐steady state to model predictions. In particular, the model predicted the behavior of the system when unexpected alterations in steady‐state operation occurred. Furthermore, the model allowed us to obtain the most appropriate H2O2/Orange II ratio in the feed to maximize the process efficiency. Biotechnol. Bioeng. 2007; 97: 1128–1137. © 2006 Wiley Periodicals, Inc.
Mineral and iron oxidation at low temperatures by pure and mixed cultures of acidophilic microorganisms
Authors: Dopson Mark , Halinen Anna‐Kaisa , Rahunen Nelli , Özkaya Bestamin , Sahinkaya Erkan , Kaksonen Anna H. , Lindström E. Börje , Puhakka Jaakko A.
Published: December 2006

An enrichment culture from a boreal sulfide mine environment containing a low‐grade polymetallic ore was tested in column bioreactors for simulation of low temperature heap leaching. PCR‐denaturing gradient gel electrophoresis and 16S rRNA gene sequencing revealed the enrichment culture contained an Acidithiobacillus ferrooxidans strain with high 16S rRNA gene similarity to the psychrotolerant strain SS3 and a mesophilic Leptospirillum ferrooxidans strain. As the mixed culture contained a strain that was within a clade with SS3, we used the SS3 pure culture to compare leaching rates with the At. ferrooxidans type strain in stirred tank reactors for mineral sulfide dissolution at various temperatures. The psychrotolerant strain SS3 catalyzed pyrite, pyrite/arsenopyrite, and chalcopyrite concentrate leaching. The rates were lower at 5°C than at 30°C, despite that all the available iron was in the oxidized form in the presence of At. ferrooxidans SS3. This suggests that although efficient At. ferrooxidans SS3 mediated biological oxidation of ferrous iron occurred, chemical oxidation of the sulfide minerals by ferric iron was rate limiting. In the column reactors, the leaching rates were much less affected by low temperatures than in the stirred tank reactors. A factor for the relatively high rates of mineral oxidation at 7°C is that ferric iron remained in the soluble phase whereas, at 21°C the ferric iron precipitated. Temperature gradient analysis of ferrous iron oxidation by this enrichment culture demonstrated two temperature optima for ferrous iron oxidation and that the mixed culture was capable of ferrous iron oxidation at 5°C. Biotechnol. Bioeng. 2007; 97: 1205–1215. © 2006 Wiley Periodicals, Inc.
Kinetics of iron oxidation by Leptospirillum ferriphilum dominated culture at pH below one
Authors: Özkaya Bestamin , Sahinkaya Erkan , Nurmi Pauliina , Kaksonen Anna H. , Puhakka Jaakko A.
Published: December 2006

The kinetics of ferrous iron oxidation by Leptospirillum ferriphilum (L. ferriphilum) dominated culture was studied in the concentration range of 0.1–20 g Fe2+/L and the effect of ferric iron (0–60 g Fe3+/L) on Fe2+ oxidation was investigated at pH below one. Denaturing gradient gel electrophoresis of PCR amplified 16S rRNA genes followed by partial sequencing confirmed that the bacterial community was dominated by L. ferriphilum. In batch assays, Fe2+ oxidation started without lag phase and the oxidation was completed within 1 to 60 h depending on the initial Fe2+ concentration. The specific Fe2+ oxidation rates increased up to around 4 g/L and started to decrease at above 4 g/L. This implies substrate inhibition of Fe2+ oxidation at higher concentrations. Haldane equation fitted the experimental data reasonably well (R2 = 0.90). The maximum specific oxidation rate (qm) was 2.4 mg/mg VS · h, and the values of the half saturation (Ks) and self inhibition constants (Ki) were 413 and 8,650 mg/L, respectively. Fe2+ oxidation was competitively inhibited by Fe3+ and the competitive inhibition constant (Kii) was 830 mg/L. The time required to reach threshold Fe2+ concentration was around 1 day and 2.3 days with initial Fe3+ concentration of 5 and 60 g/L, respectively. The threshold Fe2+ concentration, below which no further Fe2+ oxidation occurred, linearly increased with increasing initial Fe2+ and Fe3+ concentrations. Fe2+ oxidation proceeds by L. ferriphilum dominated culture at pH below 1 even in the presence of 60 g Fe3+/L. This indicates potential of using and biologically regenerating concentrated Fe3+ sulfate solutions required, for example, in indirect tank leaching of ore concentrates. Biotechnol. Bioeng. 2007; 97: 1121–1127. © 2006 Wiley Periodicals, Inc.
Simultaneous positioning of cells into two‐dimensional arrays using ultrasound
Authors: Neild Adrian , Oberti Stefano , Radziwill Gerald , Dual Jürg
Published: December 2006

Contactless simultaneous positioning of micrometer‐sized particles in suspension (e.g., copolymer beads, living cells, silicon microparts) can be performed using ultrasound. Current devices are capable of collecting particles into planes or lines by exciting a resonance in the fluid by means of a piezoelectric transducer located beneath the fluidic cavity and are designed such that a one‐dimensional pressure field is created. The focus of this work is to collect cells in distinct point locations for potential drug screening array applications. A device to create two‐dimensional arrays of cells within a micromachined chamber is described. The chamber is etched into a silicon wafer and sealed with glass; on the underside of the silicon layer a piezoelectric actuator is attached. A signal is applied to each of two orthogonally aligned strips electrodes defined on the surface of the piezoelectric plate. These two strip electrodes create independently addressable approximately one‐dimensional pressure fields. It is shown that by applying the same signal to each electrode a diagonally aligned grid of cells can be produced. However, the independence of the two electrodes allows the application of two signals with slightly different frequencies to be applied which creates a grid of circular cell clumps highly suitable for the identified application. Biotechnol. Bioeng. 2007; 97: 1335–1339. © 2006 Wiley Periodicals, Inc.
Cooperativity and saturation in biochemical networks: A saturable formalism using Taylor series approximations
Authors: Sorribas Albert , Hernández‐Bermejo Benito , Vilaprinyo Ester , Alves Rui
Published: December 2006

Cooperative and saturable systems are common in molecular biology. Nevertheless, common canonical formalisms for kinetic modeling that are theoretically well justified do not have a saturable form. Modeling and fitting data from saturable systems are widely done using Hill‐like equations. In practice, there is no theoretical justification for the generalized use of these equations, other than their ability to fit experimental data. Thus it is important to find a canonical formalism that is (a) theoretically well supported, (b) has a saturable functional form, and (c) can be justifiably applicable to any biochemical network. Here we derive such a formalism using Taylor approximations in a special transformation space defined by power‐inverses and logarithms of power‐inverses. This formalism is generalized for processes with n‐variables, leading to a useful mathematical representation for molecular biology: the Saturable and Cooperative Formalism (SC formalism). This formalism provides an appropriate representation that can be used for modeling processes with cooperativity and saturation. We also show that the Hill equation can be seen as a special case within this formalism. Parameter estimation for the SC formalism requires information that is also necessary to build Power‐Law models, Metabolic Control Analysis descriptions or (log)linear and Lin‐log models. In addition, the saturation fraction of the relevant processes at the operating point needs to be considered. The practical use of the SC formalism for modeling is illustrated with a few examples. Similar models are built using different formalisms and compared to emphasize advantages and limitations of the different approaches. Biotechnol. Bioeng. 2007; 97: 1259–1277. © 2006 Wiley Periodicals, Inc.
The effect of histone deacetylase inhibitor trichostatin A (TSA) on the incorporation of 32P (Pi) and 3H‐palmitic acid into the phospholipids of Tetrahymena
Authors: Kovács Péter , Csaba György
Published: December 2006

Histone deacetylases (HDACs) are able to control also the acetylation of tubulin. In the present experiments the effect of trichostatin A (TSA), a HDAC inhibitor was studied on the incorporation of 3H‐palmitic acid and 32P to the phospholipids (PI, PIP, PS, PC, PA, PE) of Tetrahymena pyriformis, considering earlier observations on the microtubular system's influence on signalling in this unicellular eukaryote. Treatment with 1, 5, or 10 µM TSA was studied. The incorporation of hydrophobic tail component, palmitic acid was inhibited in a concentration dependent manner into all the phospholipids, except for PA, where the incorporation was increased. 32P incorporation was also inhibited. The possible relation between the microtubular system and signalling is discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Cellular Inhibition of Protein Tyrosine Phosphatase 1B by Uncharged Thioxothiazolidinone Derivatives
Authors: Stuible Matthew , Zhao Liang , Aubry Isabelle , Schmidt‐Arras Dirk , Böhmer Frank‐D. , Li Chao‐Jun , Tremblay Michel L.
Published: December 2006

As important regulators of cellular signal transduction, members of the protein tyrosine phosphatase (PTP) family are considered to be promising drug targets. However, to date, the most effective in vitro PTP inhibitors have tended to be highly charged, thus limiting cellular permeability. Here, we have identified an uncharged thioxothiazolidinone derivative (compound 1), as a competitive inhibitor of a subset of PTPs. Compound 1 effectively inhibited protein tyrosine phosphatase 1B (PTP1B) in two cell‐based systems: it sensitized wild‐type, but not PTP1B‐null fibroblasts to insulin stimulation and prevented PTP1B‐dependent dephosphorylation of the FLT3‐ITD receptor tyrosine kinase. We have also tested a series of derivatives in vitro against PTP1B and proposed a model of the PTP1B–inhibitor interaction. These compounds should be useful in the elucidation of cellular PTP function and could represent a starting point for development of therapeutic PTP inhibitors.
Repeat right transradial percutaneous coronary intervention in a patient with dextrocardia: The right approach to the right‐sided heart
Authors: Chen Jack P.
Published: December 2006

Dextrocardia (DC) is a rare cardiac condition in which the cardiac location, as well as apex, is rightwardly displaced. As the incidence of atherosclerotic disease is similar to that of the general population, there have been few reports of percutaneous coronary interventions (PCIs) in these patients. Proposed technical strategies for successful angiography and PCI in DC include counter‐directional torquing of the catheter, as well as right‐left mirror‐image inversion angiographic views. All previous reports of DC PCIs have been via transfemoral access.

We present a case of successful repeat transradial PCI in a patient with DC. This is first report of transradial coronary angiography, PCI, or repeat PCI in a DC patient. A literature review of technical considerations, including our own recommendations for guide catheter selection, are discussed. We also review the anatomic variations and epidemiology of DC. Although access complications for transradial PCI is known to be lower than that of the transfemoral approach, challenges in technique and concern of repeat access have limited the popularity of the former. Our report demonstrates the safety and feasibility of transradial angiography, PCI, and even repeat PCI, in the rare patient with DC. © 2006 Wiley‐Liss, Inc.
Rescue left main coronary artery stenting for acute myocardial ischemia after coronary angiography in a 7‐year‐old girl with homozygous familial hypercholesterolemia
Authors: Tissot Cecile , Cruz Eduardo da , Aggoun Yacine
Published: December 2006

Homozygous familial hypercholesterolemia (HFH), resulting from mutation of the low‐density lipoprotein (LDL) receptor gene with subsequent defective catabolism of the LDL cholesterol, leads to premature atherosclerosis and coronary artery disease. We report a successful urgent stent implantation in a 7‐year‐old patient with HFH and a severe left main coronary artery stenosis, who presented critical acute myocardial ischemia immediately after left coronary angiography. Percutaneous transluminal coronary angiography with stent implantation allowed for rapid coronary flow reestablishment without sequelae. Aggressive lipid‐lowering therapy with high doses statins and LDL‐apheresis was maintained, together with lifelong antiaggregant acetylsalicylic treatment with good short‐term patency of the stent at 1‐year follow‐up. In conclusion, coronary artery stent implantation may be considered as a valid rescue therapeutic alternative for pediatric patients with HFH and severe ostial coronary stenosis in case of emergency. © 2006 Wiley‐Liss, Inc.
A new quantitative analysis system for the evaluation of coronary bifurcation lesions: Comparison with current conventional methods
Authors: Goktekin Omer , Kaplan Sahin , Dimopoulos Konstantinos , Barlis Peter , Tanigawa Jun , Vatankulu Mehmet Akif , Koning Gerhard , Tuinenburg Joan C. , Mario Carlo Di
Published: December 2006

Background:

Objective conventional quantitative angiographic systems are designed to automatically follow the contours of straight vascular segments and not of bifurcations. Recently a new analysis method was specifically developed for bifurcation lesions, able to automatically divide the lesion into three separate segments. In this study, we aimed to assess whether the smaller interaction required by the analyst could reduce the analysis time and inter and intra observer variability when compared with a conventional analysis.

Method:

We used a dedicated system (QVA‐CMS V. 6.0 with the Bifurcation Module, MEDIS, Leiden, The Netherlands) applying a minimum cost algorithm tuned to detect the contours of the proximal main vessel (PMV), distal main vessel (DMV), and side‐branch (SB). We assessed the intra‐ and the interobserver agreement in measurements of minimal lumen diameter (MLD) and percentage diameter stenosis (%DS) of the PMV and DMV, as well as of the SB ostium in 30 angiograms of patients before and after percutaneous coronary angioplasty with stenting of both branches. The consensus between measurements by two observers and by the same observer was analyzed using the intra‐ and interclass correlation coefficient and the reliability coefficients for all measurements. Bland‐Altman plots before and after PCI were also generated to assess the relationship between variability and absolute measurements.

Results:

Before PCI, intra‐ and interobserver variabilities were consistently lower for the new QVA system, with a significant difference for lesion length in the SB. Post‐PCI data showed a greater variability in the assessment of diameter stenosis with both techniques. The time for analysis was significantly lower both before and after PCI for QVA compared with quantitative coronary angiography (QCA) (4.7 ± 1.1 min versus 6.2 ± 1.3 min, P < 0.0001).

Conclusion:

Our results demonstrate that this new quantitative bifurcation analysis system can be consistently applied to the analysis of bifurcation lesions before and after angioplasty, with an intra‐ and interobserver reproducibility equal to or better than the conventional analysis system with a significantly shorter analysis time. © 2006 Wiley‐Liss, Inc.
Predictors of restenosis after treatment of bifurcational lesions with paclitaxel eluting stents: A multicenter prospective registry of 150 consecutive patients
Authors: Mario Carlo Di , Morici Nuccia , Godino Cosmo , Goktekin Omer , Tamburino Corrado , Barbagallo Rossella , Antoniucci David , Grube Eberhard , Airoldi Flavio , Zoccai Giuseppe Biondi , Colombo Antonio , Sangiorgi Giuseppe M.
Published: December 2006

Objectives:The aim of the study was the assessment of the clinical, angiographic and procedural characteristics correlated with freedom from adverse events at 1 year in a real life setting of consecutive bifurcation lesions. Background: Even if stent implantation has shown to be superior to conventional balloon angioplasty in most coronary lesions, bifurcation treatment with stent implantation both in main and in side branch (SB) still raises controversy. Methods: We reviewed the results obtained in a prospective multicenter registry of 150 patients with 158 bifurcation lesions involving a SB of sufficient diameter to be treated, if necessary, with a polymer based paclitaxel eluting stent (PES, TAXUS). Two stents were used in 118 lesions (74.7%). Final kissing balloon inflation was performed in 87/118 lesions (73.7%) and in 30/40 lesions (75.0%) of the 2 and 1 stent group respectively. Results: At 1‐year clinical follow‐up we observed 4 stent thromboses, all involving the SBs of the 2 stents group (2.7%). Unlike previous reports, revascularization involved the main vessel in the majority of patients (21/150, 14.0%). After an exploratory multivariable analysis the only parameter predictive of target lesion revascularization (TLR) (HR 0.52; CI 95% 0.11–0.86; p = 0.02) and target vessel revascularization (TVR) (HR 0.47; CI 95% 0.14–0.90; p = 0.03) was postprocedural main branch minimal lumen diameter (MB‐MLD). Conclusions: In a real life setting of consecutive bifurcation lesions, thrombosis rate, concentrated in the SB and the 2‐stents group, and need for target lesion revascularization remain higher than in less complex lesion subgroups treated with PES. No differences in immediate success and TLR were observed between 2 stents and 1 stent groups. The frequently observed suboptimal stent expansion and final MB‐MLD predict 1 year revascularization. © 2006 Wiley‐Liss, Inc.
Left ventricular segmental dysfunction following percutaneous transcatheter closure of a membranous ventricular septal defect
Authors: Yalonetsky Sergey , Lorber Avraham
Published: December 2006

Percutaneous device closure of membranous ventricular septal defects is an attractive alternative for surgical treatment. A patient with left ventricular segmental dysfunction with infarct like ECG pattern following transcatheter membranous VSD closure is presented. Possible pathophysiological mechanisms of this phenomenon are discussed. © 2006 Wiley‐Liss, Inc.
Interatrial septum rupture during balloon measurement of a patent foramen ovale in a young patient presenting cryptogenic stroke
Authors: Bonvini Robert F. , Sigwart Ulrich , Verin Vitali
Published: December 2006

We report the case of a 36‐year‐old woman admitted for cryptogenic stroke, in whom the Patent Foramen Ovale (PFO) diameter measurement, with a purpose built sizing balloon, performed before the closure procedure, was complicated with the rupture of the inter‐atrial septum generating an Atrial Septal Defect (ASD) with a significant left‐to‐right shunt. This kind of complication may not be easy to handle, changing the initial procedural strategy from PFO to ASD closure technique requiring specific material and operator's technical skill. © 2006 Wiley‐Liss, Inc.
Detection and quantification of embolic particles during percutaneous coronary intervention to stable plaque: It correlates to coronary flow dynamics and myocardial damage
Authors: Okamura Atsunori , Ito Hiroshi , Iwakura Katsuomi , Kawano Shigeo , Kurotobi Toshiya , Date Motoo , Inoue Koichi , Ogihara Toshio , Fujii Kenshi
Published: December 2006

Objectives: We detected embolic particles liberated from plaque during percutaneous coronary intervention (PCI) as high‐intensity transient signals (HITS) with a Doppler guidewire and studied their impact on coronary flow dynamics and the myocardium in patients with stable angina pectoris. Background: These embolic particles during PCI may cause myocardial injury. However, this was difficult to confirm because it was impossible to detect embolic particles. Methods: We performed balloon angioplasty followed by stenting in 31 patients while monitoring coronary flow velocity. After PCI, we measured average peak velocity at baseline and after infusion of adenosine 5′‐triphosphate to calculate coronary flow velocity reserve (CFVR) and coronary resistance index (CRI). In patients with PCI to the left coronary artery (n = 21), we calculated relative CFVR as the ratio of CFVR in the target vessel to that in the reference vessel. We measured cardiac troponin T (cTnT) the day after PCI. Results: HITS were detected in 27 (87%) of 31 patients and the majority were observed after stenting. The total number of HITS was correlated with CRI (r = 0.36, P = 0.049) or relative CFVR (r = 0.65, P = 0.0036) but not with CFVR (r = 0.048, P = 0.82). Thirteen patients showed elevated cTnT (range, 0.05–0.31 ng/ml) and the total number of HITS was greater in those with elevated cTnT than in those without elevated cTnT (24 ± 9 vs. 10 ± 7, P = 0.0007). Conclusions: Embolic particles are frequently observed during PCI to stable plaque and the majority are liberated after stenting. There appears to be a quantitative relationship between amounts of HITS and coronary microvessel dysfunction and minor myocardial injury. © 2006 Wiley‐Liss, Inc.
Relocation of minimal luminal diameter after bare metal and drug‐eluting stent implantation: Incidence and impact on angiographic late loss
Authors: Costa Marco A. , Sabaté Manel , Angiolillo Dominick J. , Hu Paula , Jimenez‐Quevedo Pilar , Corros Cecilia , Alfonso Fernando , Hernandez‐Antolin Rosana , Macaya Carlos , Bass Theodore A.
Published: December 2006

Late loss (LL) has been a fundamental angiographic end‐point in drug‐eluting stents (DES) clinical trials. However, calculation of LL may be affected by a mismatch between post‐procedure (PO) and follow‐up (FU) sites of the minimal lumen diameter (MLD). Our aims were to investigate the incidence and methodological implications of the relocation of MLD after bare metal (BMS), sirolimus‐eluting (SES), and paclitaxel‐eluting (PES) stent implantation. Data from DIABETES I and II trials, which involved diabetic patients treated with BMS, SES, and PES, were analyzed. Angiographic data with matched projections between PO and 9‐month angiographic FU were included. In‐stent, in‐lesion, and in‐segment analyses included conventional and customized sub‐segmental (5‐mm/subsegment) methodology. MLD relocation was considered when the sites of MLD shifted a distance ≫ the intrinsic variability of the method. Conventional LL, site matched LL, maximal LL (MaxLL), and average LL (AvgLL) were calculated. Relationships between various LL and 1‐year target lesion revascularization (TLR) were investigated. Post MLD was located distally, outside the stent, in ≥65% of the analyses. At FU, MLD relocation occurred in 70.5% (BMS), 40% (SES), and 35% (PES). MLD shifted ≥11 mm on average, mainly towards the stented segment. MLD relocation still occurred in 42.8% (BMS), 33.7% (SES), and 36.4% (PES), when analysis was restricted to in‐stent segment. Among LL measurements, MaxLL showed the best association with TLR rates. Relocation of the MLD is a frequent phenomenon after both BMS and DES, and should be taken into account when calculating LL. Comprehensive LL analyses, including MaxLL and AvgLL, provides a better appraisal of the biological and clinical effectiveness of DES. © 2006 Wiley‐Liss, Inc.
Percutaneous coronary intervention of a circumflex chronic total occlusion using an epicardial collateral retrograde approach
Authors: Lane Rebecca E. , Ilsley Charles D.J. , Wallis William , Dalby Miles C.D.
Published: December 2006

Antegrade disobliteration of a chronic total coronary occlusion (CTO) may be technically difficult in spite of the use of customized equipment. Retrograde approaches via intramyocardial septal or bypass grafts have been described. We report a successful Percutaneous intervention of a proximal circumflex CTO using a retrograde approach via an epicardial collateral. © 2006 Wiley‐Liss, Inc.
Diabetes mellitus does not preclude stabilization or improvement of renal function after stent revascularization in patients with kidney insufficiency and renal artery stenosis
Authors: Silva Jose A. , Potluri Srinivas , White Christopher J. , Collins Tyrone J. , Jenkins J. Stephen , Subramanian Rajesh , Ramee Stephen R.
Published: December 2006

Objective: To assess the impact of stent revascularization on the renal function of diabetic and nondiabetic patients with renal insufficiency. Background: Renal artery revascularization has been shown to stabilize or improve renal function in patients with significant renal artery stenosis and impaired renal function. However, some studies have suggested negligible or no benefit of renal function in diabetic patients with the same condition. Methods: We retrospectively compared data from 50 consecutive patients undergoing renal artery stent placement with renal insufficiency (serum creatinine ≥1.5–4.0 mg/dl) and global ischemia (bilateral or solitary [single] kidney renal artery stenosis) There were 17 diabetic (DM) and 33 nondiabetic (NDM) patients. The endpoints included the follow‐up measurements of renal function, blood pressure, and number of antihypertensive medications. Results: After stent placement, at a mean follow‐up of 42 ± 18 months (range: 6–62 months), 79% NDM (N = 26), and 76% DM patients (N = 13) (P = NS) had improvement in the slope of the reciprocal of creatinine (1/SCr), indicating a beneficial effect in renal function in many patients. Conclusion: Renal artery stent placement appears to be equally beneficial in preserving renal function in DM and NDM patients with ischemic nephropathy and global renal ischemia. © 2006 Wiley‐Liss, Inc.
Magnetic navigation system used successfully to cross a crushed stent in a bifurcation that failed with conventional wires
Authors: Ramcharitar Steve , Patterson Mark S. , van Geuns Robert‐Jan , Serruys Patrick W.
Published: December 2006

Bifurcation lesions can be technically demanding to manage, and even in the era of drug eluting stents, their procedural success is variable. The use of the crush technique followed by “kissing” balloon postdilatation has been shown to improve the overall outcome. However, crossing the crushed stent is essential to allow performance of a final dilatation with “kissing” balloons and is regarded as the main Achilles' heel of this technique. In this report, we describe the first reported, planned procedure to use a magnetic navigation system to steer a wire through the crushed stent to use “kissing” balloons that had previously failed with conventional wires. © 2006 Wiley‐Liss, Inc.
Coarctation of the aorta: Stenting in children and adults
Authors: Golden Alex B. , Hellenbrand William E.
Published: December 2006

Coarctation of the aorta may present in infants, children, or adults, and it requires treatment to prevent serious morbidity and mortality. Recent advances in equipment and a growing collective experience have made placement of balloon‐expandable stents a safe and effective alternative to surgery or angioplasty in a growing range of patients. This review seeks to provide a working aid for stenting of coarctation of the aorta, based on the techniques and technical considerations in practice at our institution. Between 1989 and 2005, the Congenital Cardiovascular Interventional Study Consortium (CCISC), a consortium of 17 centers, of which our institution is the largest contributor, performed 588 stent placements for coarctation of the aorta. Of the 588 procedures, 580 (98.6%) were successful, as defined by reduction of the gradient to less than 20 mm Hg or increase of the ratio of the diameter of the coarctation area (CoA) to the diameter of the descending aorta (DAo) to at least 0.8. There were a total of 84 complications occurring in 69/588 (11.7%) cases. The most common significant complications were femoral access vessel related 15/588 (2.6%), aneurysm formation 13/588 (2.2%), aortic dissection 9/588 (1.5%), and cerebrovascular accident 6/588 (1.0%). There were two procedure‐related deaths (0.3%) recorded in the 16‐year period. Many of these significant complications occurred in the same patients. Balloon‐expandable stents should be considered a safe and very effective treatment modality in a significant subset of patients with coarctation of the aorta. © 2006 Wiley‐Liss, Inc.
Spontaneous migration of an inferior vena cava filter resulting in cardiac tamponade and percutaneous filter retrieval
Authors: Vergara Gaston R. , Wallace William F. , Bennett Kenneth R.
Published: December 2006

Thromboembolic disease accounts for thousands of hospitalizations every year in the US. Its primary management consists of anticoagulation. However, in certain instances this may be contraindicated or not sufficient. Mechanic occlusion of the inferior vena cava (IVC) becomes then a viable alternative. In this case a 35‐year‐old man presented with a saddle pulmonary embolus but was unable to be anticoagulated due to intestinal bleed. A removable IVC filter was then placed. The filter spontaneously migrated into the right atrium causing severe tricuspid regurgitation, perforation of the atrial wall, and cardiac tamponade. The device was successfully retrieved percutaneously and the patient discharged from the hospital in stable condition. This case illustrates the potentially lethal complications associated with the use of IVC filters, as well as the possibility to percutaneously recover them from within the right atrium. © 2006 Wiley‐Liss, Inc.
Impact of renal insufficiency on clinical and angiographic outcomes following percutaneous coronary intervention with sirolimus‐eluting stents
Authors: Nakazawa Gaku , Tanabe Kengo , Aoki Jiro , Yamamoto Hirosada , Higashikuni Yasutomi , Onuma Yoshinobu , Yachi Sen , Nakajima Hiroyoshi , Hara, Kazuhiro
Published: December 2006

Background

Background: Sirolimus‐eluting stents (SES) have been demonstrated to reduce restenosis. However, there have been few studies evaluating the impact of renal insufficiency on the angiographic as well as clinical outcomes after SES implantation. Methods: This study was composed of 304 consecutive patients having 361 lesions who underwent percutaneous coronary intervention with SES. The patients were divided into 3 groups according to renal function (group 1 [n = 204]; creatinine clearance (Ccr) ≥≥60ml/min, group 2 [n = 69]; Ccr <60 ml/min, group 3 [n = 31]; hemodialysis). Clinical and angiographic follow‐up were evaluated at 8 months. Results: Clinical follow‐up was obtained in all patients and angiographic follow‐up was obtained in 283 patients (93.1%). Patients in group 3 showed a higher incidence of previous coronary artery bypass graft surgery, and there were more female gender, hypertensive, and less hyperlipidemia in this group. Late lumen loss at 8 months was significantly different among the 3 groups (group 1; 0.16 ± 0.46 mm, group 2; 0.44 ± 0.62 mm, group 3; 0.81 ± 0.88 mm, P < 0.0001). Major adverse cardiac events (MACE) were documented in 22 patients (10.8%) in group 1, 13patients (18.8%) in group 2, and 12 patients (38.7%) in group 3, respectively (P = 0.0002). Conclusion: Neointimal growth following SES implantation is more pronounced in patients with renal insufficiency, especially those undergoing dialysis, compared with patients with normal renal function. Regardless of the beneficial effect of SES, the increased risk of MACE mainly due to high incidence of target vessel revascularization in the subgroup of patients with renal insufficiency should be taken into account. © 2006 Wiley‐Liss, Inc.
Factors predictive of cardiac events and restenosis after sirolimus‐eluting stent implantation in small coronary arteries
Authors: Lee Cheol Whan , Suh Jon , Lee Se‐Whan , Park Duk‐Woo , Lee Seung‐Hwan , Kim Young‐Hak , Hong Myeong‐Ki , Kim Jae‐Joong , Park Seong‐Wook , Park, Seung‐Jung
Published: December 2006

Objectives:

Predictors of cardiac events and restenosis after sirolimus‐eluting stent (SES) implantation in small coronary arteries were evaluated.

Background:

Although SES implantation has markedly reduced the risk of restenosis, small vessel disease remains a major cause of SES failure.

Methods:

We prospectively investigated the factors predictive of cardiac events and restenosis in 1,092 consecutive patients who received SES implantation for 1,269 lesions in small coronary arteries (≤2.8 mm). Follow‐up angiography at 6 months was performed in 751 patients with 889 lesions (follow‐up rate 70.3%).

Results:

Restenosis (diameter stenosis ≥ 50%) was angiographically documented in 65 patients with 77 lesions (8.7%): 55 focal (71.4%), 8 diffuse (10.4%), 2 diffuse proliferative (2.6%), and 12 total (15.6%). Lesion length, stent length, reference artery size, and in‐stent restenotic lesions were univariate predictors of restenosis. By multivariate analysis, lesion length (OR 1.04; 95% CI 1.02–1.05; P < 0.001) and in‐stent restenotic lesions (OR 3.38; 95% CI 1.80–6.35; P < 0.001) were significant independent predictors of restenosis. During follow‐up (23.2 ± 7.9 months), there were 17 deaths (5 cardiac and 12 noncardiac), 5 nonfatal Q‐wave myocardial infarctions, and 42 target lesion revascularizations. The cumulative probability of survival without major adverse cardiac events (MACE) was (96.6 ± 0.6)% at 1 year and (95.1 ± 0.7)% at 2 years. In multivariate analysis, lesion length (HR 1.04; 95% CI 1.01–1.07; P = 0.004) and in‐stent restenotic lesions (HR 3.29; 95% CI 1.58–6.86; P = 0.001) were independently related to MACE.

Conclusions:

SES implantation in small coronary arteries is safe and effective, with lesion length having a major impact on restenosis and MACE. © 2006 Wiley‐Liss, Inc.
Comparison of radial versus femoral approach for percutaneous coronary interventions in octogenarians
Authors: Jaffe Ronen , Hong Tony , Sharieff Waseem , Chisholm Robert J. , Kutryk Michael J.B. , Charron Thierry , Cheema Asim N.
Published: December 2006

Background: The safety and efficacy of a radial approach for percutaneous coronary intervention (PCI) in octogenarians is not well established. Methods: To evaluate the benefits of a radial approach for preventing vascular complications after PCI, clinical, procedural, and outcome data were prospectively collected and compared for 228 octogenarians undergoing elective PCI either through a radial or a femoral approach. Results: Radial approach was associated with longer cannulation (3.1 ± 2.9 vs. 2.0 ± 2.0 min, P < 0.001) and fluoroscopy times (19.3 ± 16.1 vs. 16.1 ± 11.8 min, P = 0.04), greater utilization of contrast media (224 ± 46 vs. 182 ± 20 ml, P < 0.001) and higher crossover rate (11 vs 4%, P = 0.03) to alternate access site compared with the femoral approach. However, ambulation time (5.2 ± 3.1 vs. 11.6 ± 6.3 hr, P < 0.001), access site bleeding (4 vs. 14%, P = 0.007), hematoma (1 vs. 11%, P = 0.001) or any vascular complication (5 vs 26%, P = 0.001) were significantly reduced with a radial approach. Procedural success rates were equivalent with both approaches. Multivariate regression analysis identified radial approach (OR = 0.23; CI = 0.08, 0.65) as an independent negative predictor of postprocedural vascular complications. Conclusion: Radial approach for PCI in octogenarians is technically challenging for the operator and exposes patients to greater volume of nephrotoxic contrast media. However, it results in early ambulation and significantly reduces vascular complications in this high risk population. These findings support a strategy of preprocedural risk assessment and use of radial approach for PCI in a select group of octogenarians to maximize benefits offered by this technique. © 2006 Wiley‐Liss, Inc.
Stent fracture: An unusual cause of late restenosis after sirolimus‐eluting stent placement
Authors: Mehrle Anderson , Skelton Thomas , Almonacid Alexandra
Published: December 2006

Stent fracture is uncommon but may have consequences including restenosis. To date, stent fractures reported have been related to aggressive post dilation. We describe a case that involves fracture of a stent deployed to nominal pressure. Unlike most stent fractures reported that involve stent struts only our case demonstrated circumferential disruption with complete separation of the stent segments. © 2006 Wiley‐Liss, Inc.
Transcatheter closure of secundum atrial defect in small children
Authors: Cardenas L. , Panzer J. , Boshoff D. , Malekzadeh‐Milani S. , Ovaert C.
Published: December 2006

Objective: To assess safety and efficacy of transcatheter atrial septal defect (ASD) closure in small children. Background: Percutaneous closure of ASD is a well accepted alternative to surgery. Reported experience in small children remains, however, scarce. Methods: Fifty‐two children underwent percutaneous ASD closure at a weight ≤15 kg, in four Belgian tertiary referral paediatric cardiology centers. Indication for treatment, device implantation rate, procedural details, complication rate, residual shunt on echocardiography, and impact of procedure on symptoms were retrospectively analyzed. Results: Mean age at procedure was 36 months (7–60), mean weight 13 kg (4.7–15). Associated cardiac lesions were seen in 21% of the patients and noncardiac in 32.7%. Most patients (69.2%) were symptomatic. Mean ASD size was 12 mm (range 5–20 mm). A device could be inserted in 49 patients (94%). No major complications occurred. Minor complications occurred in 8 patients (15.4%) including device embolization in 2, successfully treated with transcatheter retrieval and second device insertion. Mean follow‐up reached 27 months (0.03–61.2). Residual shunt was absent, trivial, or small in 93% (n = 42) at latest follow‐up. Clinical improvement was noted in 91.7% of the symptomatic patients. Minor complications were more frequent in the presence of large ASDs (>15 mm) but not in smaller babies (<10 kg). Conclusion: Patients ≤15 kg requiring ASD closure form a special population with high incidence of associated anomalies and medical conditions. For this particular set of patients, percutaneous closure is a valid alternative. Asymptomatic or mildly symptomatic children should be treated at a later age. © 2006 Wiley‐Liss, Inc.
Enantioseparation of extended metal atom chain complexes: Unique compounds of extraordinarily high specific rotation
Authors: Warnke Molly M. , Cotton F. Albert , Armstrong Daniel W.
Published: December 2006

Extended metal atom chains (EMACs) contain a linear metal chain wrapped by various ligands. Most complexes are of the form M3(dpa)4X2, where M = metal, dpa = 2,2′‐dipyridylamide, and X = various anions. The ligands form helical coils about the metal chain, which results in chiral EMAC complexes. The EMACs containing the metals Co and Cu were partially separated in polar organic mode using a vancomycin‐based chiral stationary phase. Under similar conditions, two EMACs with Ni metal and varying anions could be baseline separated. The polar organic mode was used because of the instability of the compounds in aqueous mobile phases. Also, these conditions are more conducive to preparative separations. Polarimetric measurements on the resolved enantiomers of Ni3(dpa)4Cl2 indicate that they have extraordinarily high specific rotations (on the order of 5000 deg cc/g dm). Chirality, 2007. © 2006 Wiley‐Liss, Inc.