bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of active angiotensin‐I converting enzyme inhibitory peptides derived from bovine β‐casein by recombinant DNA technologies
Authors: Losacco Maurizio , Gallerani Raffaele , Gobbetti Marco , Minervini Fabio , De Leo Francesca
Published: August 2007

A wide range of anti‐hypertensive peptides potentially able to lower blood pressure through the inhibition of vasoactive enzymes such as angiotensin‐I converting enzyme (ACE) are known. Currently, ACE‐inhibitory peptides can be produced from precursor proteins via enzymatic hydrolysis by proteolytic enzymes, or food fermentation with proteolytic starter cultures. These approaches are neither selective nor easy. In this study a novel procedure has been developed, based on recombinant DNA technologies, for the production of highly purified fractions of three polypeptides derived from bovine β‐casein active as ACE inhibitors in vitro. The procedure includes peptide expression in Escherichia coli cells as recombinant fusion proteins, purification by affinity chromatography, cleavage by proteinase from a selected strain of Lactobacillus helveticus and isolation of bioactive peptides (BPs). The reported concentration of inhibitor needed to reduce at 50% ACE activity (IC50) values for single BP calculated in inhibiting the ACE enzyme gave results in agreement with the same parameters available in literature for other milk‐derived BPs. This procedure could be used to obtain quantities of pure peptides to determine their interactions with ACE, with the aim of designing peptides that have stronger inhibitory properties and exhibit new pharmacological profiles. Moreover, its scale up would be of commercial interest for the production of functional foods, e.g., milk beverages with blood pressure‐lowering effects.
A unique physical‐chemistry approach for fabricating cell friendly surfaces
Authors: Irvine Scott , Sullivan Alice C. , McEwan Jean R. , Jayasinghe Suwan N.
Published: August 2007

Recent interests in the fabrication of bio/cell‐friendly surfaces are consistently gaining much scientific coverage as these methods could be explored as novel regenerative and therapeutic medicinal protocols. Essentially two main components govern this aspect, the processing methodology possessing the required robustness to fabricate a wide range of materials and, not least, the synthesised materials that need to be cell‐compatible both in the short and long term after processing. In the study reported here we have combined one such robust jetting approach with a specially formulated siloxane sol. This has several unique properties in itself, and these have been demonstrated here to have a positive effect on the seeded cells. The current work demonstrates that this approach has great promise as a novel methodology for surface engineering for a wide range of applications spanning the physical to the life science areas of research.
Combined removal of sulfur compounds and nitrate by autotrophic denitrification in bioaugmented activated sludge system
Authors: Manconi I. , Carucci A. , Lens P.
Published: August 2007

An autotrophic denitrification process using reduced sulfur compounds (thiosulfate and sulfide) as electron donor in an activated sludge system is proposed as an efficient and cost effective alternative to conventional heterotrophic denitrification for inorganic (or with low C/N ratio) wastewaters and for simultaneous removal of sulfide or thiosulfate and nitrate. A suspended culture of sulfur‐utilizing denitrifying bacteria was fast and efficiently established by bio‐augmentation of activated sludge with Thiobacillus denitrificans. The stoichiometry of the process and the key factors, i.e. N/S ratio, that enable combined sulfide and nitrogen removal, were determined. An optimum N/S ratio of 1 (100% nitrate removal without nitrite formation and low thiosulfate concentrations in the effluent) has been obtained during reactor operation with thiosulfate at a nitrate loading rate (NLR) of 17.18 mmol N L−1 d−1. Complete nitrate and sulfide removal was achieved during reactor operation with sulfide at a NLR of 7.96 mmol N L−1 d−1 and at N/S ratio between 0.8 and 0.9, with oxidation of sulfide to sulfate. Complete nitrate removal while working at nitrate limiting conditions could be achieved by sulfide oxidation with low amounts of oxygen present in the influent, which kept the sulfide concentration below inhibitory levels. Biotechnol. Bioeng. 2007;98: 551–560. © 2007 Wiley Periodicals, Inc.
Monitoring denitrification by pH‐Stat titration
Authors: Ficara Elena , Canziani Roberto
Published: August 2007

An improved pH‐stat titrimetric procedure was developed, validated, and extensively applied to monitor biological heterotrophic denitrification in a lab‐scale sequencing batch reactor (SBR). So far, titrimetric procedures were not successful in monitoring denitrification processes in full‐scale wastewater (WW) treatment plants, mainly because the stoichiometric ratio between proton production and nitrate reduction is highly variable due to variability of both biomass and influent WW characteristics. In this article, a new titration procedure is proposed where a simple calibration step is performed before each experimental test. This procedure allows for the assessment of (i) nitrate content in a sample of mixed liquor; (ii) the maximum denitrification rate of sludge when fed on acetate; and (iii) the denitrification potential (DNP) of different substrates. As for (i), validation by comparison with spectrophotometric measures indicated an average discrepancy of less than 3% on more than 40 samples; as for (ii) and (iii) collected values compared well with literature data. The titrimetric method proposed here is also capable of assessing the biomass anoxic yield in a very simple way, since it does not require any analytical nitrate determination. According to the results of this experimentation, titrimetry appeared to be a simple, inexpensive, and powerful tool for monitoring and operating denitrification processes in WW treatment plants. Biotechnol. Bioeng. 2007;98: 368–377. © 2007 Wiley Periodicals, Inc.
Improving the growth rate of Escherichia coli DH5α at low temperature through engineering of GroEL/S chaperone system
Authors: Lee Jae‐Hun , Heo Mi‐Ae , Seo Joo‐Hyun , Kim June‐Hyung , Kim Byung‐Gee , Lee Sun‐Gu
Published: August 2007

GroEL/S is a molecular chaperone system in Escherichia coli which not only assists the folding of intracellular proteins but also affects the cellular activity against the change of environmental condition. Here we show that the growth rate of E. coli DH5α can be improved at low temperature by expressing a GroEL/S variant achieved through irrational protein engineering approach. The GroELS variant (GroELSvar) accelerating the growth of E. coli DH5α was screened through enrichment culture of the mutant libraries obtained by random mutagenesis. E. coli DH5α harboring the groELSvar gene exhibited approximately 1.5–2 times higher growth rate compared to the strain with wild‐type GroELS at 15–30°C. At 10°C, a temperature that the growth of E. coli DH5α almost stops, the GroELSvar triggered the growth of E. coli DH5α. We identified that seven nucleotides of groELS gene and six amino acids of the GroELS were changed through the mutagenesis and screening. Site directed mutagenic analysis revealed that H360 in GroELvar is the most crucial residue determining the activity of GroELSvar and more than one of the other residues in GroELvar may be additionally involved in the activity of GroELSvar. The improvement of growth rate induced by the GroELSvar was observed only in the strain DH5α and not detected in other E. coli strains, such as BL21, BW25113, codon+, JM110, Top10, and XL1‐blue. Biotechnol. Bioeng. 2008;99: 515–520. © 2007 Wiley Periodicals, Inc.
Prediction of diffusion coefficients of plasmids
Authors: Prazeres D.M.F.
Published: August 2007

The ability to predict diffusion coefficients is important in the design, analysis, and operation of plasmid downstream processing operations such as membrane and fixed‐bed chromatography. A correlation is proposed to predict the diffusion coefficient, D, of supercoiled plasmid DNA molecules in dilute solutions on the basis of the molecular weight, M, or size. Experimental data (18 points) collected from the literature confirmed the proposed variation of D with plasmid molecular weight as D ∝ M−2/3, for molecules within the 1,800–287,100 base‐pair range. The correlation was able to estimate the available experimental results with an average error of 6.3%. Biotechnol. Bioeng. 2008; 99; 1040–1044. © 2007 Wiley Periodicals, Inc.
Treatment of halogenated organic compounds and monitoring of microbial dynamics in up‐flow fixed bed reactors under sequentially alternating pollutant scenarios
Authors: Emanuelsson Maria A.E. , Osuna M. Begoña , Sipma Jan , Castro Paula M.L.
Published: August 2007

Two up‐flow fixed bed reactors (UFBR) were operated for 8 months treating a model synthetic wastewater containing 2‐fluorobenzoate (2‐FB) and dichloromethane (DCM). The stability of the reactors under dynamic conditions, that is, sequentially alternating pollutants (SAP), shock loads, and starvation periods was assessed. Two support materials were used: expanded clay (EC) that does not adsorb 2‐FB or DCM, and granular‐activated carbon (GAC) that adsorbs 180 mg g−1 of 2‐FB and 390 mg g−1 of DCM. The reactors were inoculated with a 2‐FB‐degrading strain (FB2) and a DCM degrader (TM1). 2‐FB was fed at organic loads ranging from 0 to 800 mg L−1 d−1, while DCM was fed at 0–250 mg L−1 d−1. 2‐FB or DCM were never detected at the outlet of the GAC reactor, while in the EC reactor outlet small amounts were observed. Nevertheless, the highest biological elimination capacity was observed in the EC reactor (over 700 mg L−1 d−1 of 2‐FB). DGGE analysis revealed a fairly stable bacterial community with the largest shifts occurring during starvation periods and changes in feed composition. Several bacterial strains isolated from the reactors showed capacity for 2‐FB degradation, while only strain TM1 degraded DCM. Biotechnol. Bioeng. 2008;99: 800–810. © 2007 Wiley Periodicals, Inc.
Impact of gentrification on environmental pressure in service micro‐enterprises
Authors: Mir Debby F. , Sanchez Adolfo E.
Published: August 2007

The study investigates whether local service micro‐enterprises (MEPs) in gentrifying neighborhoods face increasing complaints triggering inspections and regulatory pressure.

 Environmental records from 1992 to 2000 were reviewed for 383 filling stations, motor vehicle repair firms and dry cleaners in five Chicago neighborhoods. Significant differences in the number of complaints and inspections were found between gentrifying and gentrified neighborhoods, especially in the higher‐income gentrified neighborhood. No significant difference was found in enforcement. Regulatory pressure from environmental agencies adds to the financial, social and other regulatory pressures facing service MEPs that drove away or closed manufacturing firms in the past. Alternatively, new market opportunities with regulatory and social pressure could provide incentives to improve environmental behavior. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Identification of a Hybrid PKS/NRPS Required for Pseurotin A Biosynthesis in the Human Pathogen Aspergillus fumigatus
Authors: Maiya Shubha , Grundmann Alexander , Li Xiang , Li Shu‐Ming , Turner Geoffrey
Published: August 2007

The genome sequence of Aspergillus fumigatus revealed the presence of a single hybrid polyketide synthase–non‐ribosomal peptide synthetase (PKS/NRPS) gene that is present within a cluster of five genes suggestive of its involvement in secondary metabolism. Here, we present evidence that it is required for the biosynthesis of pseurotin A, a compound with an unusual heterospirocyclic γ‐lactam structure. We have confirmed that the genome reference strain A. fumigatus Af293 produces pseurotin A, a compound previously reported to be a competitive inhibitor of chitin synthase and an inducer of nerve‐cell proliferation. Deletion or overexpression of the PKS/NRPS gene psoA in A. fumigatus leads to the absence or accumulation of pseurotin A, respectively; this indicates that this gene is essential for the biosynthesis of pseurotin A. It is likely that the first product of psoA is converted to pseurotin A by the products of other genes in this cluster.
A Type II Polyketide Synthase is Responsible for Anthraquinone Biosynthesis in Photorhabdus luminescens
Authors: Brachmann Alexander O. , Joyce Susan A. , Jenke‐Kodama Holger , Schwär Gertrud , Clarke David J. , Bode Helge B.
Published: August 2007

Type II polyketide synthases are involved in the biosynthesis of numerous clinically relevant secondary metabolites with potent antibiotic or anticancer activity. Until recently the only known producers of type II PKSs were members of the Gram‐positive actimomycetes, well‐known producers of secondary metabolites in general. Here we present the second example of a type II PKS from Gram‐negative bacteria. We have identified the biosynthesis gene cluster responsible for the production of anthraquinones (AQs) from the entomopathogenic bacterium Photorhabdus luminescens. This is the first example of AQ production in Gram‐negative bacteria, and their heptaketide origin was confirmed by feeding experiments. Deletion of a cyclase/aromatase involved in AQ biosynthesis resulted in accumulation of mutactin and dehydromutactin, which have been described as shunt products of typical octaketide compounds from streptomycetes, and a pathway for AQ formation from octaketide intermediates is discussed.
Heterogeneity of atherosclerotic plaque characteristics in human coronary artery disease: A three‐dimensional intravascular ultrasound study
Authors: Box Lyndon C. , Angiolillo Dominick J. , Suzuki Nobuaki , Box Lesleigh A. , Jiang Julie , Guzman Luiz , Zenni Martin A. , Bass Theodore A. , Costa Marco A.
Published: August 2007

Objectives: The objective of this study was to describe the intraplaque variability of coronary atherosclerosis in humans. Background: Atherosclerosis is a heterogeneous process. The degree and patterns of intraplaque heterogeneity are not well described. This study uses 3D intravascular ultrasound (IVUS) to examine variability in individual atherosclerotic plaques in human coronary arteries. Methods: IVUS images of 170 coronary plaques in 98patients were evaluated. Each plaque was divided into proximal, middle, and distal sections. Quantitative and qualitative analyses were performed for each section using a dedicated 3D IVUS protocol. Intralesion heterogeneity was assessed between sections. Results: Heterogeneity in composition was observed in most plaques (89%). The pattern of remodeling was heterogeneous in 23% of lesions. External elastic membrane (EEM) areas demonstrated an average percent deviation of 28.9% ± 15.5%. Positive remodeling was associated with longer lesions (≫ median length of 12.7 mm) (P = 0.031). Soft and calcific sections had a smaller mean EEM area (P = 0.034). Calcific lesions had a smaller mean lumen area (P = 0.027) and a greater percent plaque burden (PPB) (P = 0.001). Neither the location within the vessel or within the plaque was associated with plaque morphology. Greater qualitative heterogeneity was found in patients presenting with acute coronary syndrome (P < 0.001). Conclusions: Our results demonstrate a high degree of heterogeneity in composition and morphological features within individual atherosclerotic plaques in human coronary arteries. Intraplaque heterogeneity represents a challenge for imaging protocols correlating plaque features with cardiovascular events and for the development of future therapeutic options. © 2007 Wiley‐Liss, Inc.
Thoracic radiotherapy in patients with lymphoma and restenosis after coronary stent placement
Authors: Schömig Kathrin , Ndrepepa Gjin , Mehilli Julinda , Pache Jürgen , Kastrati Adnan , Schömig Albert
Published: August 2007

Objectives:

The aim of this study was to assess the incidence of restenosis after coronary stenting in patients with lymphoma treated with thoracic radiation. Background: Patients with Hodgkin lymphoma treated with thoracic radiation have an increased incidence of coronary artery disease (CAD). The incidence of restenosis after percutaneous coronary interventions is completely unknown. Methods: This study included 12,626 consecutive patients with CAD treated with coronary stenting during a 10‐year period. Within this cohort, three subgroups of patients were assessed: patients with lymphoma and previous thoracic radiation (15 patients), patients with lymphoma without thoracic radiation (7 patients) and patients without lymphoma or previous thoracic radiation (control group; 12,604 patients). Coronary stenting was performed after a median [25th; 75th percentiles] of 8 years [4; 17] after thoracic radiation. The primary end point of the study was restenosis at 6‐month coronary angiography. Results: Six‐month coronary angiography was performed in 14 patients (93%) in the group with lymphoma and radiation, 6 patients (86%) in the group with lymphoma without radiation and 10,032 patients (80%) in the control group (P = 0.38). Angiographic restenosis was found in 12 patients (85.7%) in the group with lymphoma and radiation, 1 patient (16.7%) in the group with lymphoma without radiation and 2,555 patients (25.5%) in the control group (P < 0.001). Multiple logistic regression identified thoracic radiation as an independent predictor of coronary restenosis (odds ratio 21.7, 95% confidence interval, 4.7–100.9, P < 0.001). Conclusions: Patients with lymphoma treated with thoracic radiation have an increased risk of restenosis after coronary artery stenting. © 2007 Wiley‐Liss, Inc.
Significant aortic regurgitation associated with transcatheter closure of perimembranous ventricular septal defects with a deficient aortic rim
Authors: Kenny Damien , Tometzki Andrew , Martin Robin
Published: August 2007

We report on two patients who developed significant aortic regurgitation during transcatheter closure of a perimembranous ventricular septal defect, both requiring further surgical intervention. Both patients were noted prior to the procedure to have limited subaortic margins to the defect. The potential mechanisms for development of aortic regurgitation in this setting are discussed. © 2007 Wiley‐Liss, Inc.
Sirolimus‐eluting stent implantation for treatment of proximal left anterior descending coronary artery lesions: Long‐term outcome and predictors of adverse cardiac events
Authors: Lee Cheol Whan , Tan Chong‐Hiok , Suh Jon , Lee Se‐Whan , Park Duk‐Woo , Lee Seung‐Whan , Kim Young‐Hak , Hong Myeong‐Ki , Kim Jae‐Joong , Park Seong‐Wook , Park Seung‐Jung
Published: August 2007

Objectives: Acute and long‐term results after sirolimus‐eluting stent (SES) implantation of proximal left anterior descending coronary artery (LAD) disease were evaluated. Background: Although SES has been used increasingly for the treatment of LAD disease, data regarding their safety and efficacy in a real‐world population are limited. Methods: We investigate the short‐ and long‐term results in 966 patients who underwent SES implantation for stenosis of proximal LAD. Results: The procedural success rate was 97.6%, and procedural non‐Q‐wave myocardial infarction (MI) rate was 14.5%. In‐hospital major complications occurred in five patients (0.5%), including three deaths and two Q‐wave MIs. During follow‐up (20.4 ± 8.9 months), there were 16 deaths (1.7%; 10 cardiac, 6 noncardiac), 2 Q‐wave MIs, and 22 target lesion revascularizations (2.3%). Late stent thrombosis occurred in two patients (0.2%), 14 and 23 months after the procedure. The event‐free survival rates for cardiac death/Q‐wave MI were 98.6% ± 0.4% at 1 year and 97.8% ± 0.6% at 2 years. The cumulative probabilities of survival without major adverse cardiac events (MACE) were 96.7% ± 0.6% at 1 year and 95.4% ± 0.8% at 2 years. In multivariate analysis, stented length (HR 1.04, 95%CI 1.01–1.07, P = 0.009) and infarct‐related artery (HR 5.18, 95%CI 1.09–24.64, P = 0.039) were independently related to cardiac death/Q‐wave MI. In addition, stented length (HR 1.04, 95%CI 1.02–1.06, P << 0.001) and left ventricular dysfunction (HR 2.66, 95%CI 1.07–6.63, P = 0.036) were significant independent predictors of MACE. Conclusions: SES implantation for proximal LAD disease appears safe and effective in a real‐world population, and the independent predictors of MACE included stented length and left ventricular dysfunction. © 2007 Wiley‐Liss, Inc.
Stent thrombosis after sirolimus‐ and paclitaxel‐eluting stent implantation in daily clinical practice: Analysis of a single center registry
Authors: Trabattoni Daniela , Fabbiocchi Franco , Montorsi Piero , Ravagnani Paolo , Galli Stefano , Teruzzi Giovanni , Calligaris Giuseppe , De Martini Stefano , Bartorelli Antonio L.
Published: August 2007

Objectives: To evaluate stent thrombosis (ST) rate after sirolimus‐eluting stent (SES) and paclitaxel‐eluting stent (PES) implantation in daily clinical practice. Background: The safety profile of drug‐eluting stents (DES) was predominantly determined in randomized clinical trials with narrow inclusion criteria. Concerns about ST have been raised in unselected patients treated with DES. Methods: We prospectively evaluated 867 patients undergoing DES implantation, 618 patients with SES, and 249 with PES, in a single academic center. Results: Multivessel disease was present in 72% of patients, multivessel stenting was performed in 17%, long (>18 mm) lesions were treated in 30%, and multiple stents per lesion were needed in 31%. On average, 1.7 ± 0.8 stents per patient were implanted (stented segment length: 32 ± 25 mm/vessel). IIb/IIIa inhibitors were used in 7.5%. Intravascular ultrasound (IVUS) guidance was employed in 65% of SES and 50% of PES implantations, and the procedural success rate was 100% in SES and 99% in PES cases. Six‐month follow‐up was performed in all patients, whereas one‐year follow‐up was completed in 87% patients of the SES group and in 95% of the PES group. We considered that ST occurred when angiographic evidence of thrombus was available, or when patients experienced sudden cardiac death or either ST‐elevation or non‐ST‐elevation myocardial infarction (MI) through the 12‐month follow‐up period. The overall incidence of ST was 0.9% (0.4% in SES and 2% in PES, P = 0.03). Of the eight ST, two (25%) were acute, four (50%) subacute, one (12.5%) was a late event, and one (12.5%) a very late event. Seven ST were confirmed by angiography. No IVUS guidance was used in 4/8 (50%) ST patients, while antiplatelet therapy was prematurely discontinued in 3/8 (37.5%). Among ST patients, mortality and nonfatal MI rates were 25% and 37.5%, respectively. No ST was diagnosed between 6 and 12 months, while one very late thrombosis occurred at 15 months. Conclusions: The incidence of ST after DES use in daily clinical practice is low and similar to that observed in randomized clinical trials. © 2007 Wiley‐Liss, Inc.
Resolution of migraine by transcatheter patent foramen ovale closure with premere occlusion system in a preliminary series of patients with previous cerebral ischemia
Authors: Rigatelli Gianluca , Cardaioli Paolo , Braggion Gabriele , Giordan Massimo , Fabio Dell'Avvocata , Aggio Silvio , Roncon Loris , Chinaglia Mauro
Published: August 2007

Background:

Transcatheter closure of PFO with nitinol devices may be problematic in young patients with migraine due the risk of late erosions. Alternative devices with less amount of metal as the last generation devices may be preferable in such cases. We present the results of transcatheter closure of PFO with the last generation Premere Occlusion System device in a preliminary series of young adults with migraine and previous cerebral ischemia.

Methods:

During a 12‐month period (January 31, 2006 to December 31, 2006) 26 patients (18 female and 8 male, mean age 40 ± 3.7 years) with previous stroke and severe disabling migraine were referred to our center for transcatheter closure of PFO. Migraine disability assessment score (MIDAS) was used to assess MHA incidence and severity. Patients were selected for Premere occlusion system (absence of atrial septal aneurysm and length >15 mm) on the basis of presence/absence of right and left bulging atrial septal aneurysm and length of PFO channel (<15 mm or >15 mm) on transesophageal echocardiography. Transesophageal echocardiography and transcranial Doppler were performed at 1 month, transthoracic echocardiography and cerebral magnetic resonance imaging at 6 and 12 months. Cardiologic and neurological visit was scheduled at 1, 6, and 12 months with MIDAS questionnaire administration.

Results:

Ten patients (2 males, mean age 32 ± 7.6 years, mean MIDAS score 38.9 ± 5.8) underwent transcatheter PFO closure with the Premere occlusion system. Mean fossa ovalis diameters by ICE measurement was 20.6 ± 3.1 mm. Thus, two 20‐mm and eight 25‐mm Premere devices were implanted. The procedure was successful in all of the patients with no perioperative and in‐hospital complications. After a mean follow‐up of 10.9 ± 5.8 months, all patients were free from migraine symptoms (mean MIDAS score 2.9 ± 1.9) with PFO complete closure in all patients on transesophageal and transcranial Doppler ultrasound.

Conclusion:

While waiting for larger studies evaluating the impact of new generation devices in curing PFO‐related migraine, this preliminary anecdotal series suggests that the Premere occlusion system may be an effective and safe device for young patients with previous cerebral ischemia and migraine at least in the midterm period. © 2007 Wiley‐Liss, Inc.
Promise and challenges of bioabsorbable stents
Authors: Waksman Ron
Published: August 2007

Despite the development and progression of metallic stents, many concerns still remain because of their permanent nature. Although metallic stents are effective in preventing recoil and late restenosis after coronary angioplasty, they continue to have limitations such as stent thrombosis and mismatch of the stent to the vessel size. Thus, the concept of bioabsorbable stents has emerged as an alternative to permanent metal stents. This review will outline concepts, material designs, preclinical, and initial clinical experimental studies with bioabsorbable stents. © 2007 Wiley‐Liss, Inc.
Treatment of severe infrapopliteal vascular disease using a novel atherectomy device: A case report
Authors: Caputo Ronald P. , Ebner Adrian , Garcia Lawrence
Published: August 2007

We report two first in man cases of percutaneous revascularization for severe intrapopliteal arterial disease using the novel PV atherectomy device. © 2007 Wiley‐Liss, Inc.
Anti‐platelet and anti‐thrombotic approaches in patients undergoing percutaneous coronary intervention
Authors: Garg Rajeev , Uretsky Barry F. , Lev Eli I.
Published: August 2007

Over the past three decades, there has been a tremendous increase in the use of percutaneous coronary interventions (PCI) for the treatment of patients with atherosclerotic coronary artery disease. However, PCI causes disruption of atherosclerotic plaque and denudation of the endothelium, leading to stimulation of platelet aggregation and activation of the coagulation cascade. Therefore, anti‐platelet and anti‐thrombotic agents have a pivotal role as adjuncts before, during and after PCI, in order to minimize the risk of procedural ischemic complications, such as myocardial infarction, stent thrombosis, and various degrees of myonecrosis. The current article presents a comprehensive review of the evolution of current anti‐platelet and anticoagulation regimens used in the setting of PCI. It starts with a summary of the current perspective of the coagulation process along with platelet activation and aggregation. The review then focuses specifically on individual anti‐platelet and anti‐thrombotic drugs including their mechanism of action and the scientific evidence which led to their use in PCI. Finally, we present summary recommendations from the AHA/ACC guidelines for individual anticoagulant and anti‐platelet regimens given peri‐PCI. © 2007 Wiley‐Liss, Inc.
The AST petal dedicated bifurcation stent: First‐in‐human experience
Authors: Ormiston John , Webster Mark , El‐Jack Seifeddin , McNab Duncan , Simpson Plaumann Stephanie
Published: August 2007

The aim of this first‐in‐human study was to evaluate the feasibility and safety of the novel AST petal side‐access bifurcation stent. Outcomes following percutaneous coronary intervention for bifurcations remain inferior to those of nonbifurcated lesions. Even with drug‐eluting stents, restenosis occurs especially at the side‐branch (SB) ostium. The petal stent uniquely deploys strut elements into the SB, supporting the ostium and carina. The primary endpoint of this 13‐patient prospective registry was in‐hospital major adverse cardiac events (MACE). Secondary end points included acute minimum lumen diameter (MLD) at the SB ostium, lesion success, device success, procedural success, 30‐day MACE, and 4‐month SB ostial MLD. The study lesion was successfully treated in 13 patients with the study stent being successfully implanted in 12. Target lesions were left anterior descending coronary artery in nine subjects, left circumflex in three, and right coronary artery in one. In‐hospital MACE were limited to two non‐Q‐wave myocardial infarctions. In‐stent main branch MLD increased from a mean of 0.63 ± 0.45 mm to 2.61 ± 0.47 mm at the index procedure and for this initial bare metal version of the stent, 4‐month mean MLD measured 1.02 ± 0.42mm and there was target vessel revascularization on two patients. The feasibility of safely deploying this first‐generation petal stent was demonstrated in selected patients with challenging coronary bifurcation lesions. It is a promising platform for drug delivery, with unique scaffolding of the side‐branch ostium. © 2007 Wiley‐Liss, Inc.
Treatment of instent restenosis following stent‐supported renal artery angioplasty
Authors: Zeller Thomas , Rastan Aljoscha , Schwarzwälder Uwe , Mueller Christian , Schwarz Thomas , Frank Ulrich , Bürgelin Karlheinz , Sixt Sebastian , Noory Elias , Beschorner Ulrich , Hauswald Kirsten , Branzan Daniela , Neumann Franz‐Josef
Published: August 2007

Objectives:

We prospectively studied the long‐term outcome of endovascular treatment of instent renal artery stenosis (IRAS).

Background:

Restenosis is a considerable drawback of stent‐supported angioplasty of renal artery stenosis especially in small vessel diameters. The appropriate treatment strategy is not yet defined.

Patients and Methods:

During a 10‐year period 56 consecutive patients (65 lesions) with their first IRAS were included in a prospective follow‐up program (mean follow‐up 53 ± 25 months, range 6–102). Primary endpoint of the study was the reoccurrence of IRAS (≥ 70%) after primarily successful treatment of the first IRAS determined by duplex ultrasound.

Results:

Primary success rate was 100%, no major complication occurred. Nineteen lesions were treated with plain balloon angioplasty (group 1, 30%), 42 lesions with stent‐in‐stent placement (group 2, 65%) using various bare metal balloon expandable stents, and 4 lesions with drug‐eluting stent angioplasty (group 3, 6%). During follow‐up, overall 21 lesions (32%) developed reoccurrence of IRAS: n = 7/19 in group 1 (37%), n = 14/42 in group 2 (33%), and n = 0/4 in group 3 (0%; P = 0.573). Reoccurrence of IRAS was more likely to occur in smaller vessel diameters than in larger ones [3–4mm: 4/7 (57%); 5 mm: 11/26 (42%); 6 mm: 5/25 (20%); 7 mm: 1/7 (14%), P = 0.088]. Multivariable analysis found bilateral IRAS and IRAS of both renal arteries of the same side in case of multiple ipsilateral renal arteries as independent predictors for reoccurrence of IRAS.

Conclusion:

Treatment of IRAS is feasible and safe. The data demonstrate a nonsignificant trend towards lower restenosis with restenting of IRAS versus balloon angioplasty of IRAS. Individual factors influence the likelihood of reoccurrence of IRAS. © 2007 Wiley‐Liss, Inc.
Interventional stroke therapy: Current state of the art and needs assessment
Authors: White Christopher J. , Cates Christopher U. , Cowley Michael J. , Weiner Bonnie H. , Carpenter Jeffrey S. , Hopkins L. Nelson , Jaff Michael R. , Ramee Stephen R. , Rymer Marilyn M. , Wholey Mark H.
Published: August 2007

The primary therapeutic strategy for ischemic stroke, as for MI patients, is early reperfusion. Improvement in stroke treatment will require dedicated stroke centers to emulate MI quality indicators such as minimizing the “door‐to‐balloon time”. A critical element in achieving this goal will be organizing the existing multidisciplinary pool of carotid interventionalists to provide the endovascular component of the acute care for ischemic stroke patients. © 2007 Wiley‐Liss, Inc.
Reproductive Accuracy of Generic Omega Parameter Safety Valve Two Phase Critical Mass Flow Models Based on Water and Refrigerant R‐134a Data
Authors: Derlien H. , Friedel L.
Published: August 2007

The modified Omega method included in ISO/FDIS 4126‐10 provides the highest accuracy compared to other modified models frequently used in practice and academia. At the same time, it allows for an exceptionless oversizing of the necessary relief area under all test conditions. Nevertheless, the average or statistical reproductive accuracy is characterized by an unacceptably high logarithmic scatter of about 80 % for fluid dynamic critical steam/water and two‐phase refrigerant R‐134a flow. When applying the method to sizing situations with predicted mass flow qualities in excess of 1 % an acceptably modest oversizing is maintained.
Predicting Separation of Lower Hydrocarbon from Natural Gas by a Nano‐Porous Membrane using Capillary Condensation
Authors: Ahmad F. , Mukhtar H. , Man Z. , Dutta B. K.
Published: August 2007

In the present work, the potential of a nano‐porous membrane for predicting the separation of lower hydrocarbons from natural gas by capillary condensation was explored. While a gas permeates through a capillary at a suitable pressure, the adsorbed layer may attain a thickness enough to fill the entire membrane pore. Poiseuille flow of the condensed phase follows. Our computed results have established that for a passage through a nano‐porous membrane, gas having lower condensation pressure condenses in the pores at a pressure which is about an order of magnitude lower than its vapor pressure at the concerned temperature. In the case of propane/methane and butane/methane binary mixtures, propane and butane are preferentially condensed and permeation rates up to 700 g mol/m2 s bar for propane and 600 g mol/m2 s bar for butane have been achieved at a temperature lower than the critical temperature of the permeating species and higher than the critical temperature of the non‐permeating species. Since methane has a much lower critical temperature than both propane and butane, it gets physically dissolved in the condensed phase of propane, butane in the case of propane/methane and butane/methane binary mixtures, respectively. An equation of state (EOS) approach has been adopted to calculate the fugacity of methane in the gas, as well as in the condensed phase, in order to estimate its solubility. The Peng‐Robinson equation of state was used. Computation of the separation factor for methane/propane and methane/butane was performed over a wide range of temperature, pressure, and gas composition. The separation factor which is expectedly a function of these variables ranged from 0.3–75 for methane/propane and 0.7–140 for methane/butane binary mixtures. It has been established that an acceptable degree of separation is achievable at moderate pressure and at low temperature for the removal of propane and butane from natural gas. The results have the potential to be used for further refinement and optimization of the process conditions so that this strategy can be exploited for large‐scale removal of lower hydrocarbon from natural gas at a low cost.
Rational Design of MOFs Constructed from Modified Aromatic Amino Acids
Authors: Xie Yu , Yu Zhaopeng , Huang Xiaoying , Wang Zhiyong , Niu Liwen , Teng Maikun , Li Jing
Published: August 2007

Three Phe and Tyr derivatives, 2‐amino‐3‐(4‐aminophenyl)‐propionic acid (AAP), 3E‐[5‐(2‐amino‐2‐carboxyethyl)‐2‐methoxyphenyl]‐acrylic acid (AMPA) and 3‐(4‐aminophenyl)‐2‐(carboxymethyl‐amino)‐propionic acid (ACP) have been chosen as the ligands to construct four kinds of novel metal‐organic frameworks (MOFs) (five structures). These structures are, [CdII{(R)‐AAP}(Py)(H2O)]⋅(ClO4), (R)‐1; [CdII{(S)‐AAP}(H2O)2]⋅(ClO4), (S)‐2; [Zn2II{(R,S)‐AMPA}(H2O)], (R,S)‐3; [Zn2II{(R)‐ACP}(Py)3]⋅(ClO4)2, (R)‐4; and the inversion twin of (R)‐1. Rational design to adjust the “depth” and the “width” of ligands can mediate the size and the shape of the grids of these 2D layers. Additionly, among these compounds, three pure chiral coordination polymers are obtained, owing to the inducement of chirality by the modified amino acids. This property makes them potential NLO materials.
Platinum‐Catalyzed Multistep Reactions of Indoles with Alkynyl Alcohols
Authors: Bhuvaneswari Sivakolundu , Jeganmohan Masilamani , Cheng Chien‐Hong
Published: August 2007

PtCl2 effectively catalyzes the multistep reaction of N‐methyl indole (1 a) with pent‐3‐yn‐1‐ol (2 a) in THF at room temperature for 2 h to give indole derivative 3 a, which contains a five‐membered cyclic ether group at C3 in 93 % yield. Under similar reaction conditions, various substituted N‐methyl indoles 1 b–h and indole (1 i) reacted efficiently with 2 a to afford the corresponding indole derivatives 3 b–h and 3 i in 48–91 and 72 % yields. The results showed that N‐methyl indoles with electron‐donating substituents were more reactive affording higher product yields than those with electron‐withdrawing groups. Likewise, various substituted but‐3‐yn‐1‐ols 2 b–e and other longer chain alkynyl alcohols 2 f–i also underwent a cyclization–addition reaction with N‐methyl indole (1 a) to provide the corresponding cyclization–addition products 3 j–m and 3 a, 3 j, and 3 n–o in good to excellent yields. The present platinum‐catalyzed cyclization–addition reaction can be further extended into N‐methyl pyrrole. Mechanistically, the catalytic reaction proceeds by an intramolecular hydroalkoxylation of alkynyl alcohol to afford cyclic enol ether followed by the addition of the CH bond of indole to the unsaturated moiety of cyclic enol ether providing the final product. Experimental evidence to support this proposed mechanism is provided.
Iterative Synthesis of Spacered Glycodendrons as Oligomannoside Mimetics and Evaluation of Their Antiadhesive Properties
Authors: Heidecke Christoph D. , Lindhorst Thisbe K.
Published: August 2007

Dendrimer chemistry is an attractive concept for mimicry of the highly branched character of the bioactive carbohydrates found as part of a cell's sugar coat, called the glycocalyx. Glycodendrimers have thus been used to study biological processes occurring on cell surfaces, such as bacterial adhesion. This paper details a new approach in glycodendrimer synthesis, in which a 3,6‐diallylated carbohydrate is utilised as core molecule, hydroboration–oxidation is the activating step, and glycosylation with branched and unbranched sugar trichloroacetimidates is used for dendritic growth. To obtain pure dendritic pseudo‐tri‐ and ‐heptasaccharides in good yields, radical addition of mercaptoethanol to peripheral double bonds was also evaluated with great success. A collection of six new hyperbranched glycodendrons was tested for their potential as inhibitors of type 1 fimbriae‐mediated bacterial adhesion in an ELISA and the results were interpreted with regard to sugar valency and spacer characteristics.
Synthesis and Metal Complexes of Chiral C2‐Symmetric Diamino–Bisoxazoline Ligands
Authors: Guillemot Geoffroy , Neuburger Markus , Pfaltz Andreas
Published: August 2007

A synthetic route to tetradentate chiral N4 ligands has been developed with the aim to study the potential of corresponding iron and manganese complexes as catalysts for enantioselective epoxidation. These ligands, which contain two oxazoline rings and two trialkylamino groups as coordinating units, are readily prepared in enantiomerically pure form by the reaction of chiral 2‐chloromethyloxazolines with achiral N,N′‐dimethylethane‐1,2‐diamine or chiral (R,R)‐N,N′‐dimethylcyclohexane‐1,2‐diamine. The ligands derived from N,N′‐dimethylethane‐1,2‐diamine reacted with anhydrous metal halides MnCl2 and FeCl2 in a stereoselective manner to give octahedral mononuclear complexes that have the general formula Δ‐[(L)MCl2]. In contrast, the ligands derived from N,N′‐dimethylcyclohexane‐1,2‐diamine formed complexes with different coordination modes depending on the diastereomer employed: in one case the metal ion was found to be pentacoordinate, in the other case a hexacoordinated complex was observed. The structure of a series of Fe and Mn complexes was determined by X‐ray analysis. The coordination chemistry of these ligands was further studied by X‐ray and NMR analyses of the diamagnetic isostructural complexes [(L)ZnCl2]. Analogous ionic complexes, which were prepared by removing chloride with silver trifluoromethanesulfonate or hexafluoroantimonate, were tested as catalysts for the epoxidation of olefins.
A Spectroscopic Study of the Reduction of Geometrically Restrained Viologens
Authors: Benniston Andrew C. , Harriman Anthony , Li Peiyi , Rostron James P. , Harrington Ross W. , Clegg William
Published: August 2007

A small series of N,N′‐dimethyl‐4,4′‐bipyridinium dication derivatives (commonly known as viologens) has been synthesized and fully characterized; a short dialkoxy tether attached at the 3,3′‐positions is used to alter the central dihedral angle. These angles were determined by both single‐crystal X‐ray diffraction and by computational studies made for the dication, radical cation, and neutral species in a solvent reservoir. The dihedral angle derived for the dication controls the first reduction potential, whereas the geometry of the resultant π‐radical cation determines the magnitude of the second reduction potential. The optical absorption spectra recorded for the various species, and especially those of the radical cations, and the EPR spectral parameters of the π‐radical cations also depend on the molecular geometry. In particular, the central dihedral angle influences the spin density distribution around the aromatic nucleus and, by way of comparison to the parent viologen, it has been possible to resolve the angle dependence from the inherent inductive effect of the strap. These results are considered in terms of the degree of electronic communication between the two aromatic rings, as controlled by the length of the tether.
Porous Metal Oxides as Gas Sensors
Authors: Tiemann Michael
Published: August 2007

Semiconducting metal oxides are frequently used as gas‐sensing materials. Apart from large surface‐to‐volume ratios, well‐defined and uniform pore structures are particularly desired for improved sensing performance. This article addresses the role of some key structural aspects in porous gas sensors, such as grain size and agglomeration, pore size or crack‐free film morphology. New synthesis concepts, for example, the utilisation of rigid matrices for structure replication, allow to control these parameters independently, providing the opportunity to create self‐diagnostic sensors with enhanced sensitivity and reproducible selectivity.
Improving sensitivity in chiral supercritical fluid chromatography for analysis of active pharmaceutical ingredients
Authors: Helmy Roy , Biba Mirlinda , Zang Jia , Mao Bing , Fogelman Kimber , Vlachos Vaso , Hosek Paul , Welch Christopher J.
Published: August 2007

Despite its status as the preferred method for routine enantiopurity analysis in pharmaceutical research, supercritical fluid chromatography (SFC) has historically been unsuited for the accurate and precise measurements required for release testing of active pharmaceutical ingredients (APIs) under current good manufacturing processes (cGMPs). Insufficient signal to noise, as compared to HPLC, has heretofore been the major limitation of the chiral SFC approach. We herein describe an investigation into the fundamental limitations and sources of noise in the SFC approach, identifying thermal, electronic, and mechanical sources of noise within the flow cell as key parameters contributing to reduced sensitivity. A variety of instrument modifications are explored, ultimately leading to the development of a new and improved flow cell and other instrument modifications that allow suitable sensitivity and accuracy to carry out GMP release testing for enantiopurity analysis using SFC. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Enantioselective analysis of citalopram and demethylcitalopram in human and rat plasma by chiral LC‐MS/MS: Application to pharmacokinetics
Authors: Rocha Adriana , Marques Maria P. , Coelho Eduardo B. , Lanchote Vera L.
Published: August 2007

Citalopram (CITA) is available as a racemic mixture and as a pure enantiomer. Its antidepressive action is related to the (+)‐(S)‐CITA and to the metabolite (+)‐(S)‐demethylcitalopram (DCITA). In the present investigation, a method for the analysis of CITA and DCITA enantiomers in human and rat plasma was developed and applied to the study of pharmacokinetics. Plasma samples (1 ml) were extracted at pH 9.0 with toluene:isoamyl alcohol (9:1, v/v). The CITA and DCITA enantiomers were analyzed by LC‐MS/MS on a Chiralcel® OD‐R column. Recovery was higher than 70% for both enantiomers. The quantification limit was 0.1 ng/ml, and linearity was observed up to 500 ng/ml plasma for each CITA and DCITA enantiomer. The method was applied to the study of the kinetic disposition of CITA administered in a single oral dose of 20 mg to a healthy volunteer and in a single dose of 20 mg/kg (by gavage) to Wistar rats (n = 6 for each time). The results showed a higher proportion of the (−)‐(R)‐CITA in human and rat plasma, with S/R AUC ratios for CITA of 0.28 and 0.44, respectively. S/R AUC ratios of DCITA were 0.48 for rats and 1.04 for the healthy volunteer. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Synthesis and chiroptical properties of a helical poly(phenylacetylene) bearing optically active pyrene pendants
Authors: Lin Hongzhen , Morino Kazuhide , Yashima Eiji
Published: August 2007

A novel poly(phenylacetylene) derivative bearing optically active pyrene moieties as the pendant groups (poly‐(R)‐1) was prepared by the polymerization of the corresponding monomer (R)‐1 in the presence of a rhodium catalyst, and its chiroptical property was investigated. Poly‐(R)‐1 exhibited an induced circular dichroism (ICD) in the polymer backbone region due to the predominantly one‐handed helical conformation. The ICD pattern dramatically changed and was accompanied by inversion of the Cotton effect sign in response to a change in the temperature and solvent, indicating that poly‐(R)‐1 underwent a helix–helix transition in response to the external stimuli. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
Synthesis of new chiral cis‐3‐hydroxyazetidines and their application in diethylzinc addition to aldehydes
Authors: Zhang Zhanbin , Li Min , Zi Guofu
Published: August 2007

A new series of chiral cis‐3‐hydroxyazetidines have been prepared from (R)‐1‐phenylethylamine. They have excellent catalytic activities and enantiomeric selectivities in asymmetric addition of diethylzinc to aromatic aldehydes. Chirality, 2007. © 2007 Wiley‐Liss, Inc.