bluuebunny/crossref_metadata_2025 huggingface dataset:
Sorption of tributyltin in seawater by municipal solid waste compost
Authors: Vassallo Ruth , Vella Alfred J.
Published: September 2002

The use of municipal solid waste (MSW) compost as a sorbent for tributyltin (TBT) in seawater was investigated. TBT‐contaminated seawater, both artificially prepared and that collected from Msida Creek yacht marina (Malta), was allowed to percolate through untreated and water‐washed columns of compost and then analysed for organotins using gas chromatography‐flame photometric detection. About 90% of dissolved TBT ranging in concentration from about 800 to 8000 ngSnl−1 was sorbed by treating 500 ml solutions with 100 g untreated compost. On the other hand, no detectable breakthrough of TBT was observed from compost that had previously been washed by water to remove soluble organic matter. Breakthrough of TBT from unwashed compost is thought to be due to formation of complexes between the soluble organic matter in compost and aquated TBT, which renders the organotin more hydrophilic. The use of washed MSW compost as sorbent for the purification of TBT‐contaminated waters generated in large quantity during hull‐cleaning activities in drydocks is suggested as a mitigatory measure against the impact of TBT on the coastal marine environment. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis and biological study of a new series of bifunctional organoiron thio‐ and seleno‐terephthalate derivatives (C5H5)Fe(CO)2ECO(C6H4)COX (E = S, X = R2N, RNH, NH2, OH, Cl; E = Se, X = RNH, RS, RCOO, NH2, OH, Cl)
Authors: Maslat Ahmed O. , Jibril Ibrahim , Abussaud Mahmoud , Abd‐Alhadi Emad H. , Hamadah Zuhair
Published: September 2002

A new series of bifunctional organoiron thio‐ and seleno‐terephthalate complexes — (η‐C5H5)Fe(CO)2ECO(C6H4)COX [E = S; X = C6H11NH, (C2H5)2N; and E = Se; X = PCH3C6H4NH, C6H5C2N2OS, mNO2C6H4CHCHCOO] — has been synthesized via the organic transformation reactions of the terephthaloyl chloride precursors η‐(C5H5)Fe(CO)2ECO(C6H4)COCl with the desired nucleophiles. These new complexes were characterized by elemental analysis, IR and 1H NMR spectra. The above complexes, in addition to some other selected analogues, were tested for their antifungal, antibacterial and mutagenic activity. Our results show that all the selenium‐containing compounds have antifungal activity on Candida albicans and antibacterial effects against Bacillus subtilis and Staphylococcus aureus. Four of the six selenium‐containing derivatives exhibited growth inhibitory effects against Pseudomonas aeruginosa and/or Escherichia coli. Sulfur‐containing derivatives elicited activity against C. albicans, and each one of them showed activity against at least one of the bacterial strains that have been used in this investigation. Two selenium‐ and two sulfur‐containing derivatives showed mutagenic activity against one or more than one strain of the Salmonella typhimurium using the Ames test. Copyright © 2001 John Wiley & Sons, Ltd.
Evidence of a common pathogenesis for foregut duplications and esophageal atresia with tracheo‐esophageal fistula
Authors: Qi Bao Quan , Beasley Spencer W. , Williams Andrew K.
Published: September 2002

The pathogenesis of the alimentary tract duplications, including foregut duplications (FgD) remains speculative. The accidental finding of FgD in fetal rats with esophageal atresia and tracheoesophageal fistula (EA‐TEF) induced by Adriamycin provided an animal model to investigate a possible relationship between these two entities. Timed‐pregnant rats were intraperitoneally injected with Adriamycin (1.75 mg/kg) on gestational Days 6 to 9. Their embryos were harvested by Caesarean section from gestational Days 14 to 21. Forty‐six of embryos were processed and serially sectioned in the transverse or sagittal planes. EA‐TEF occurred in 43/46 (93%) embryos of which 11 (24%) were found to have an associated FgD located at the level where the esophagus was absent. Six FgDs communicated with the foregut or the trachea. Five noncommunicating FgDs were located between the foregut and the vertebral column. In the control embryo, the notochord was located in the centre of the vertebral column from Day 11 of the gestation. In Day 14, 15 and 16, however, embryos exposed to Adriamycin, an abnormal notochord or branch frequently was located within the mesenchyme of the maldeveloped foregut or attached to the duplication cyst. In some, it appeared that the notochord was drawing the cyst‐like structure away from the foregut. The present study confirms that duplications adjacent to the esophagus arise from the foregut and that failure of the foregut to detach from the notochord at the normal time may contribute to the development of foregut duplications. Anat Rec 264:93–100, 2001. © 2001 Wiley‐Liss, Inc.
Human reserve pluripotent mesenchymal stem cells are present in the connective tissues of skeletal muscle and dermis derived from fetal, adult, and geriatric donors
Authors: Young Henry E. , Steele Timothy A. , Bray Robert A. , Hudson John , Floyd Julie A. , Hawkins Kristina , Thomas Karen , Austin Troy , Edwards Chris , Cuzzourt Jeremy , Duenzl Mary , Lucas Paul A. , Black Asa C.
Published: September 2002

This study details the profile of 13 cell surface cluster differentiation markers on human reserve stem cells derived from connective tissues. Stem cells were isolated from the connective tissues of dermis and skeletal muscle derived from fetal, mature, and geriatric humans. An insulin/dexamethasone phenotypic bioassay was used to determine the identity of the stem cells from each population. All populations contained lineage‐committed myogenic, adipogenic, chondrogenic, and osteogenic progenitor stem cells as well as lineage‐uncommitted pluripotent stem cells capable of forming muscle, adipocytes, cartilage, bone, fibroblasts, and endothelial cells. Flow cytometric analysis of adult stem cell populations revealed positive staining for CD34 and CD90 and negative staining for CD3, CD4, CD8, CD11c, CD33, CD36, CD38, CD45, CD117, Glycophorin‐A, and HLA DR‐II. Anat Rec 264:51–62, 2001. © 2001 Wiley‐Liss, Inc.
Ultrastructure of the embryonic stem cells of the 8‐day pig blastocyst before and after in vitro manipulation: Development of junctional apparatus and the lethal effects of PBS mediated cell–cell dissociation
Authors: Talbot Neil C. , Garrett Wesley M.
Published: September 2002

Ultrastructural examination of 8‐day hatched pig blastocysts (large and small), their cultured inner cell mass (ICM), and cultured epiblast tissue (embryonic stem cells) was undertaken to assess the development of epiblast cell junctions and cytoskeletal elements. In small blastocysts, epiblast cells had no desmosomes or tight junction (TJ) connections and few organized microfilament bundles, whereas in large blastocysts the epiblast cells were connected by TJ and desmosomes with associated microfilaments. ICM isolation by immunodissection damaged the endoderm cells beneath the trophectoderm cells but did not appear to damage the epiblast cells or their associated endoderm cells. Epiblast cells in cultured ICMs were similar in character to those in the intact large blastocyst except that perinuclear microfilaments were observed. Isolated pig epiblasts, cultured for ∼36 hr on STO feeder layers, formed a monolayer whose cells were connected by TJ, adherens junctions and desmosomes with prominent microfilament bundles running parallel to the apical cytoplasmic membranes. Perinuclear microfilaments were a consistent feature in the ∼36 hr cultured epiblast cells. A feature characteristic of differentiation into notochordal cells, i.e., a solitary cilium, was also observed in the cultured epiblast. Exposure of the cultured epiblast cells to Ca++‐Mg++‐free phosphate buffered saline (PBS) for 5–10 min resulted in extensive cell blebbing and lysis. The results may indicate that pig epiblast cells could be more easily dissociated from early blastocysts (∼400 μm in diameter) if immunodissection damage to the ICM can be avoided. It may be difficult, however, to establish them as embryonic stem cell lines because the cultured pig epiblast cells were easily lysed by standard cell–cell dissociation methods. Anat Rec 264:101–113, 2001. © 2001 Wiley‐Liss, Inc.
Resistance of the insect cell line IPLB‐LdFB to salsolinol‐induced apoptosis
Authors: Ottaviani Enzo , Nappi Anthony J. , Vass Emily
Published: September 2002

Apoptosis is a form of cell death that is manifested in Parkinson’s disease (PD) and certain other neurodegenerative disorders. Metabolites of salsolinol (SAL), an intraneuronal, dopamine‐derived tetrahydroisoquinoline (TIQ), have been shown to induce apoptosis in human dopaminergic neuroblastoma cells, implicating these molecules as causative or contributory factors in the selective killing of nigrostriatal dopaminergic neurons, a cardinal manifestation of Parkinson’s disease. Since insects employ dopamine and related catecholamines in a variety of processes including cuticular sclerotization and cellular immune reactions, it was of interest to know how insect cells metabolized exogenous SAL. Propidium iodide staining combined with flow cytometry showed that IPLB‐LdFB cells from Lymantria dispar exhibited no significant (P < 0.05) increase in apoptosis when incubated for 48 h with concentrations of SAL ranging from 10 μM to 1 mM. A significant increase in apoptosis (P < 0.05) was observed in cell cultures containing the highest concentration of SAL tested (5 mM), but only 12.4% of the cells manifested this form of cell death. High pressure liquid chromatography with electrochemical detection (HPLC‐ED) was used to document the production of two potentially cytotoxic quinonoids generated during the autoxidation of SAL, a reaction that was found to be significantly (P < 0.05) enhanced by peroxidase. The resistance of IPLB‐LdFB cells to SAL‐induced apoptosis is attributed to the ability of these insect cells to metabolize and/or detoxify such dopamine‐derived catecholic TIQs. Thus, the biochemical pathways employed by insect cells in these processes may be of considerable interest to individuals investigating certain neurodegenerative disorders. Arch. Insect Biochem. Physiol. 49:1–9, 2002. © 2002 Wiley‐Liss, Inc.
Dose‐dependent pharmacokinetics of a new neuroprotective agent for ischemia‐reperfusion damage, KR‐31378, in rats
Authors: Kim Hee J. , Kim So H. , Kim Sun‐O. , Lee Dong‐H. , Lim Hong , Yoo Sung‐E. , Lee Myung G.
Published: September 2002

The dose‐dependent pharmacokinetic parameters of a new neuroprotective agent for ischemia‐reperfusion damage, KR‐31378, were evaluated after intravenous and oral administration, 10, 20, and 50 mg/kg, to rats. After intravenous administration of 50 mg/kg, the dose‐normalized (10 mg/kg) AUC (994 µg min/mL) was significantly greater than that at 10 (569 µg min/ml) and 20 (660 µg min/mL) mg/kg. This could be due to slower clearance (Cl) with increasing dosage (18.5, 14.6, and 10.2 mL/min/kg for 10, 20, and 50 mg/kg, respectively). The slower Cl with increasing dosage could be due to saturable metabolism of KR‐31378 in rats and this could be supported by significantly slower Clnr and significantly greater 24‐h urinary excretion of the drug at 50 mg/kg than those at 10 and 20 mg/kg. After oral administration of 50 mg/kg, the dose‐normalized (10 mg/kg) AUC (1160 µg min/mL) was significantly greater than that at 10 (572 µg min/mL) and 20 (786 µg min/mL) mg/kg. Note that the AUCs were comparable (not significantly different) between intravenous and oral administration at each dosage, indicating that the absorption from gastrointestinal tract was almost complete and the first‐pass (gastric, intestinal, and hepatic) effect was not considerable after oral administration to rats. Copyright © 2000 John Wiley & Sons, Ltd.
Theoretical pharmacokinetic and pharmacodynamic simulations of drug delivery mediated by blood–brain barrier transporters
Authors: Mahar Doan Kelly M. , Boje Kathleen M. K.
Published: September 2002

Pharmacokinetic/pharmacodynamic simulations were performed to assess the feasibility of central nervous system (CNS) drug delivery via endogenous transporters resident at the blood–brain barrier (BBB). Pharmacokinetic models were derived for intravenous bolus dosing of a hypothetical drug in the absence or presence of an endogenous, competing transport inhibitor. These models were linked to CNS pharmacodynamic models where the effect sites were either cell surface receptors or intracellularly localized enzymes. The response of the dependent parameter, the duration of effect (tdur), was examined in relationship to changes in the independent parameters, i.e. dose, elimination rate constant (ke1), BBB transport parameters (Km1 and Vmax1) and EC50 (effective concentration that elicits a 50% response). As expected, tdur increased with (a) increases in drug doses, (b) decreases in ke1 or (c) decreases in EC50, irrespective of the effect site. Surprisingly, endogenous transport inhibition produced decreases in drug terminal half‐life and corresponding decreases in tdur. Interestingly, tdur was independent of assigned transporter Km and Vmax when the dose/EC50 ratio (dose/EC50) was >1 (irrespective of endogenous transport inhibition), but highly dependent on Km1 and Vmax1 when dose/EC50 was (a) <1 (no endogenous transport inhibition) or (b) equal to 1 (with endogenous transport inhibition). Oral input of the endogenous transport inhibitor produced a decrease in tdur when the dose/EC50 range was 0.1–10. These simulations highlight that (a) systemic pharmacokinetic and BBB transport parameters influence tdur, (b) drug terminal half‐life is inversely related to circulating levels of endogenous inhibitors, and (c) oral ingestion of endogenous transport inhibitor(s) reduces tdur. Overall, these simulations provide insight for the feasibility of rational CNS drug design/delivery via endogenous transporters. Copyright © 2000 John Wiley & Sons, Ltd.
Why girls want to be boys
Authors: Beukeboom Leo W. , de Jong Tom J. , Pen Ido
Published: September 2002

The mechanisms by which sex is genetically determined are bewilderingly diverse and appear to change rapidly during evolution.(1) What makes the sex‐determining process so prone to perturbations? Two recent articles(2,3) explore theoretically the role of genetic conflict in sex determination evolution. Both studies use the idea that selection on sex‐determining genes may act differently in parents and in offspring and they suggest that the resulting conflict can drive changes in sex‐determining mechanisms. BioEssays 23:477–480, 2001. © 2001 John Wiley & Sons, Inc.
It ain't over till it's ova: germline sex determination in C. elegans
Authors: Kuwabara Patricia E. , Perry Marc D.
Published: September 2002

Sex determination in most organisms involves a simple binary fate choice between male or female development; the outcome of this decision has profound effects on organismal biology, biochemistry and behaviour. In the nematode C. elegans, there is also a binary choice, either male or hermaphrodite. In C. elegans, distinct genetic pathways control somatic and germline sexual cell fate. Both pathways share a common set of globally acting regulatory genes; however, germline‐specific regulatory genes also participate in the decision to make male or female gametes. The determination of sexual fate in the germline of the facultative hermaphrodite poses a special problem, because first sperm then oocytes are produced. It has emerged that additional layers of post‐transcriptional regulation have been imposed to modulate the activities of the global sex‐determining genes, tra‐2 and fem‐3; the balance between these activities is crucial in controlling sexual cell fate in the hermaphrodite germline. BioEssays 23:596–604, 2001. © 2001 John Wiley & Sons, Inc.
Pathways to photoreceptor cell death in inherited retinal degenerations
Authors: Pierce Eric A.
Published: September 2002

The mutations that cause many forms of inherited retinal degenerations have been identified, yet the mechanisms by which these mutations lead to death of photoreceptor cells of the retina are not completely understood. Investigations of the pathways from mutation to retinal degeneration have focused on spontaneous and engineered animal models of disease. Based on the studies performed to date, four major categories of degeneration mechanism can be identified. These include disruption of photoreceptor outer segment morphogenesis, metabolic overload, dysfunction of retinal pigment epithelial cells, and chronic activation of phototransduction. Future investigations will likely identify additional mechanisms of photoreceptor damage. This review will summarize what has been learned from studying animal models of non‐syndromic inherited retinal degenerations. BioEssays 23:605–618, 2001. © 2001 John Wiley & Sons, Inc.
Ethylene hormone receptor action in Arabidopsis
Authors: Chang Caren , Stadler Ruth
Published: September 2002

Small gaseous molecules play important roles in biological signaling in both animal and plant physiology. The hydrocarbon gas ethylene has long been known to regulate diverse aspects of plant growth and development, including fruit ripening, leaf senescence and flower abscission. Recent progress has been made toward identifying components involved in ethylene signal transduction in the plant Arabidopsis thaliana. Ethylene is perceived by five receptors that have similarity to two‐component signaling proteins. The hydrophobic amino‐terminus of the receptors binds ethylene, and mutations in this domain both prevent ethylene binding and confer ethylene insensitivity to the plant; the carboxyl‐terminal portion of the receptors has similarity to bacterial his tidine protein kinases. Genetic data suggest a model in which ethylene binding inhibits receptor signaling, yet precisely how these receptors function is unclear. Two of the receptors have been found to associate with a negative regulator of ethylene responses called CTR1, which appears to be a mitogen‐activated protein kinase (MAPK) kinase kinase. BioEssays 23:619–627, 2001. © 2001 John Wiley & Sons, Inc.
Utilizing genetically engineered bacteria to produce plant‐specific glucosides
Authors: Arend Joachim , Warzecha Heribert , Hefner Tobias , Stöckigt Joachim
Published: September 2002

Plant‐derived glucosides have attracted much attention due to their widespread applications. This class of products is difficult to isolate or to synthesize in pure form because of the resulting low yields. Thus, simple approaches for the generation of such glucosides would be highly beneficial. We purified and characterized a novel glucosyltransferase from plant cell suspension cultures of Rauvolfia serpentina, which showed rather low substrate specificity. We obtained its cDNA and expressed the active recombinant protein in bacteria (Escherichia coli) with excellent plant‐specific glucosylation efficiencies. Compared with the plant system, the bacteria delivered the new enzyme, which was in the form of a soluble or matrix‐bound enzyme, approximately 1800 times more efficiently for the synthesis of a wide range of glucosides. More importantly, the engineered E. coli strain allowed for in vivo glucosylation and release of the product into the culture medium, as shown by the formation of arbutin, which is a potent inhibitor of human melanin biosynthesis with commercial value. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 126–131, 2001.
Three novel high performance affinity chromatographic media for the separation of antithrombin III from human plasma
Authors: Zhao Yingxin , Zhao Rui , Shangguan Dihua , Xiong Shaoxiang , Liu Guoquan
Published: September 2002

Novel monodisperse, non‐porous, cross‐linked poly (glycidyl methacrylate) beads (PGMA) were employed as the support for high performance affinity chromatography. Heparin was covalently attached to PGMA beads by three different coupling methods. Heparin‐PGMA‐I was prepared by directly coupling amino‐groups of heparin with PGMA. Heparin‐PGMA‐II and III were prepared by the coupling of heparin to amino‐PGMA, which was obtained by amination of PGMA. Heparin‐PGMA‐II was prepared by coupling the carboxyl groups of heparin to amino‐PGMA by using water‐soluble carbodiimide as coupling reagent, and heparin‐PGMA‐III was prepared by the reductive amination of heparin and amino‐PGMA with sodium cyanoborohydride. The heparin contents of heparin‐PGMA‐I, II and III were 1.6, 10.2 and 1.0 mg/g beads, respectively. Their affinity capacities for antithrombin III were investigated. Their binding activity to antithrombin III was not proportional to the content of heparin immobilized, and heparin‐PGMA‐I was the most efficient affinity medium for antithrombin III. The resultant affinity media presented minimal non‐specific interaction with other proteins and can be used in a wide pH range. All the three heparin‐PGMA beads were exploited for the separation of antithrombin III from human plasma. The purity of antithrombin III obtained was higher than 90%, which was confirmed by high performance size exclusion chromatography. Copyright © 2001 John Wiley & Sons, Ltd.
Quantitative determination of nitrendipine and its metabolite dehydronitrendipine in human plasma using liquid chromatography–tandem mass spectrometry
Authors: Chen Xiaoyan , Zhong Dafang , Yang Hanyu , Luan Yan , Xu Haiyan
Published: September 2002

A sensitive and high‐throughput LC‐MS‐MS method was developed for simultaneous determination of nitrendipine (NIT) and its major metabolite, dehydronitrendipine (DNIT) in human plasma using nifedipine as the internal standard. Plasma samples were prepared based on a simple liquid–liquid extraction. The extracted samples were analyzed on a Zorbax SB C18 column interfaced with a triple quadrupole tandem mass spectrometer. Positive atmospheric pressure chemical ionization was employed as the ionization source. The analytes were detected by use of selected reaction monitoring mode. Standard curves were linear (r ≥ 0.995) over the concentration range of 0.4–40 ng/mL for NIT and 0.2–20 ng/mL for DNIT. The intra‐ and inter‐run precision was measured to be below 8.5% for NIT and DNIT. The inter‐run accuracy was less than 4% for the analytes. The overall extraction recoveries of NIT and DNIT were determined to be about 75% and 78% on average, respectively. The chromatographic run time was approximately 3 min. More than 120 samples could be assayed daily with this method, including sample preparation, data acquisition and processing. The method developed was successfully used to investigate plasma concentrations of NIT and DNIT in a pharmacokinetic study of volunteers who received NIT orally. Copyright © 2001 John Wiley & Sons, Ltd.
Determination of clarithromycin in human plasma by HPLC with electrochemical detection: validation and application in pharmacokinetic study
Authors: Niopas Ioannis , Daftsios Athanasios C.
Published: September 2002

A rapid, specific, precise and accurate HPLC method with electrochemical detection was developed and validated for the determination of clarithromycin in human plasma. After addition of the internal standard, the analytes were extracted from plasma under alkaline conditions with ethyl acetate:hexane 1:1. The inter‐run precision of the method was less than 4.7%, the inter‐run accuracy was better than 97.3% and the recovery of clarithromycin and roxithromycin (internal standard) were better than 82.5% and 86.2%, respectively. The method was found to be suitable for the quantitation of clarithromycin in bioequivalence and pharmacokinetic studies. Copyright © 2001 John Wiley & Sons, Ltd.
Inspection of the reversal of enantiomer migration order in ligand exchange micellar electrokinetic capillary chromatography
Authors: Lin Jin‐Ming , Hobo Toshiyuki
Published: September 2002

Enantiometers of D,L‐phenylalanine were separated by capillary electrophoresis based on the principle of ligand exchange. Copper (II) complex of 4‐hydroxy‐L‐proline was used as chiral selector. The separation and the migration order of D‐ and L‐phenylalanine were strongly affected by adding an anion surfactant sodium dodecylsulfate (SDS). Without SDS in the electrolyte, the separation was also carried out but the resolution was very small. With SDS added into the electrolyte, the resolution decreased with increasing concentration of SDS until 5.0 mM. When the concentration of SDS in the electrolyte was over 5.0 mM, inversion of the migration order of DL‐phenylalanine was observed and the resolution was also increased with increasing concentration up to 20 mM. It was interesting to find that the inversion of the migration order took place not only in the enantioscparation but also in the positional isomers. A family of a fluorinated amino acid, o‐, m‐ and p‐fluoro‐D,L‐phenylalanine was separated and the inversion of the migration order is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Combined percutaneous biosense‐guided laser myocardial revascularization and coronary intervention
Authors: Laham Roger J. , Baim Donald S.
Published: September 2002

Laser myocardial revascularization is a promising new treatment strategy for patients with severe ischemic heart disease who are not candidates for conventional percutaneous or surgical revascularization. The open chest surgical approach to transmyocardial revascularization has been approved by the FDA for the treatment of angina in inoperable patients, but has had limited use as a stand‐alone procedure. More recently, use of fiber‐optic catheters has made it possible to use a holmium:yttrium aluminum garnet laser to perform percutaneous catheter‐based transmyocardial revascularization. To the extent that many patients have a combination of ischemic sources, some amenable to conventional revascularization and some not, combination or hybrid approaches have been considered. We report herein two patients with class IV angina who underwent laser myocardial revascularization using the Biosense system and complex percutaneous coronary intervention during the same procedure. Areas amenable to conventional percutaneous coronary intervention (PCI) were so treated, and viable but ischemic areas were supplied by totally occluded native vessels and bypass grafts underwent Biosense‐guided laser myocardial revascularization (LMR). As the results of more controlled and blinded studies of laser myocardial revascularization become available (if results continue to be promising) and a better understanding of the mechanism of action of this treatment modality is achieved, LMR‐PTCA hybrid will be performed in increasing frequency. However, even after establishing LMR efficacy, studies of LMR‐PTCA hybrid should be conducted to determine the efficacy of this approach. Cathet Cardiovasc Intervent 2001;53:235–240. © 2001 Wiley‐Liss, Inc.
Endovascular repair of traumatic pseudoaneurysm by uncovered self‐expandable stenting with or without transstent coiling of the aneurysm cavity
Authors: Assali Abid R. , Sdringola Stefano , Moustapha Ali , Rihner Michael , Denktas Ali E. , Lefkowitz Michael A. , Campbell Morgan , Smalling Richard W.
Published: September 2002

Various surgical options for internal carotid or subclavian artery pseudoaneurysm repair have been reported; however, in general they have resulted in poor outcomes with high morbidity and mortality rates. Recently, these open surgical procedures have been partly replaced by percutaneous transluminal placement of endovascular devices. We evaluated the potential for using flexible self‐expanding uncovered stents with or without coiling to treat extracranial internal carotid, subclavian and other peripheral artery posttraumatic pseudoaneurysm. Three patients with posttraumatic pseudoaneurysm were treated by stent deployment and coiling (two cases) of the aneurysm cavity. In one case, a 5.0 × 47 mm Wallstent (Boston Scientific) was positioned to span the neck of the 9 × 5 mm size pseudoaneurysm (left internal carotid artery) and deployed. Angiography demonstrated complete occlusion of the pseudoaneurysm without coiling. In the second patient, a 5.0 × 31 mm Wallstent (Boston Scientific) was positioned to span the neck of the 9 × 7 mm size pseudoaneurysm (right internal carotid artery) and deployed. A total of six coils (Guglielmi Detachable Coils, Boston Scientific) were deployed into the pseudoaneurysm cavity until it was completely obliterated. In the third case, an 8.0 × 80 mm SMART (Cordis) stent was advanced over the wire, positioned to span the neck of the 10 × 7 mm size pseudoaneurysm of the left subclavian artery, and deployed. Fourteen 40 × 0.5 mm Trufill (Cordis) pushable coils were deployed into the pseudoaneurysm cavity until it was completely obliterated. At long‐term follow‐up (6–9 months), all patients were asymptomatic without flow into the aneurysm cavity by Duplex ultrasound. We conclude that uncovered endovascular flexible self‐expanding stent placement with transstent coil embolization of the pseudoaneurysm cavity is a promising new technique to treat posttraumatic pseudoaneurysm vascular disease by minimally invasive methods, while preserving the patency of the vessel and side branches. Cathet Cardiovasc Intervent 2001;53:253–258. © 2001 Wiley‐Liss, Inc.
In vivo assessment of stent recoil in normal porcine arteries: Evaluation of contemporary stent designs
Authors: Garcia Lawrence A. , Hosley Susanne E. , Baim Donald S. , Carrozza Joseph P.
Published: September 2002

Acute stent recoil has been observed following balloon deflation in normal and diseased coronary arteries, and the magnitude varies by stent design. We sought to evaluate acute stent recoil in five new stents. Twenty‐five stents (four Crown, five Nir Conformer Royale, five Crossflex, five SupraG, and six GFX) were implanted in six Yorkshire pigs. All stents were expanded using a noncompliant balloon (balloon:artery ratio 1.2:1.0). Continuous ultrasound imaging was performed during stepwise balloon inflation and deflation using a 0.018″ imaging core. Maximum cross‐section areas (CSA) and minimal luminal diameter (MLD) were measured at 12 atm and immediately following balloon deflation. Maximum stent CSA matched expected balloon CSA. Area and diameter recoil were calculated as 1 − (CSAdeflation/CSAmax) and 1 − (MLDdeflation/MLDmax), respectively. Upon deflation, all stents showed recoil from maximal CSA. Area recoil was significantly lower for slotted‐tube stents than modular stents (12.6% ± 1.6% vs. 23.2 ± 3.5%; P < 0.05). In compliant, nonatherosclerotic porcine coronary arteries, acute stent recoil for the four slotted‐tube designs ranged from 8.4% to 18.0% by area. The modular stent tested was associated with significantly greater acute recoil than the slotted‐tube stents. Cathet Cardiovasc Intervent 2001;53:277–280. © 2001 Wiley‐Liss, Inc.
Intramyocardial delivery of FGF2 in combination with radio frequency transmyocardial revascularization
Authors: Bao Jialin , Naimark Wendy , Palasis Maria , Laham Roger , Simons Michael , Post Mark J.
Published: September 2002

Therapeutic angiogenesis and percutaneous transmyocardial revascularization (PMR) are potentially synergistic modalities to improve myocardial perfusion. To evaluate the efficiency of FGF2 delivery into an area that has been radio frequency (RF) ablated, we studied two catheter‐based delivery methods, a direct injection system (Stiletto) and a combined RF ablation‐delivery system (RF‐PMR). Four groups (n = 3/group) of pigs received six transendocardial injections of 125I‐FGF2/fluorescent microspheres with either the Stiletto or the RF‐PMR catheter. RF‐PMR injections were preceded by a 0.6 sec RF ablation step. After either 1 or 24 hr, hearts and other tissues were harvested. Intramyocardial deposition sites were located with UV light and isolated. Specific activity per site was expressed as a percentage of total activity injected per site corrected for quenching. Injection site recovery was high for both catheter systems (average = 88%) and systemic uptake was low (< 6% in the liver). FGF2 retention was significantly higher with the Stiletto than the RF‐PMR catheter (Stiletto 1 hr 41% ± 17%, 24 hr 26% ± 10%, RF‐PMR 1 hr 21% ± 14%, 24 hr 13% ± 8%; P < 0.001), principally explained by the differences in catheter design. The Stiletto has a retractable needle and is optimized for intramyocardial delivery, whereas infusion from the RF‐PMR device occurs at the endocardial surface and relies on channels created during RF ablation. Overall, FGF2 retention after transendocardial intramyocardial delivery by the Stiletto or the RF‐PMR system is significantly higher than previously observed for intracoronary, intravenous and intrapericardial delivery. In conclusion, the combination of RF ablation and growth factor delivery using the RF‐PMR system is feasible and efficient. Cathet Cardiovasc Intervent 2001;53:429–434. © 2001 Wiley‐Liss, Inc.
Enantiomerization of 3‐Carbethoxy‐l,4‐benzodiazepin‐2‐one: Combined chiral HPLC and spectroscopic study
Authors: Abatangelo Anna , Zanetti Flavio , Navarini Luciano , Kontrec Darko , Vinković Vladimir , Šunjić Vitomir
Published: September 2002

Recently developed chiral HPLC columns CHIRIS AD1 and CHIRIS AD2 have been demonstrated to separate racemic, configurationally unstable ethyl‐7‐chloro‐2‐oxo‐5‐phenyl‐2,3‐dihydro‐1H‐1,4‐benzodiazepine‐3‐carboxylate (1) and its 3‐methyl congener 2; fast on‐column enantiomerization of configurationally unstable 1 was observed, however. Addition of 0.1% of AcOH to the eluting mixture inhibits enantiomerization, whereas the same percentage of Et3N completely precludes enantioseparation, suggesting base‐catalysis by free β‐aminoethyl groups, present in low percentage in chiral stationary phase (CSP). When both CSPs were prepared under conditions of nonexhaustive acylation by N‐DNB‐α‐aminoacids, no separation of 1 was observed. The rate of enantiomerization on CHIRIS AD2 was determined at 25°C, the mechanism is discussed, and experimental results correlated with calculated relative stabilities of the tautomers la–c. Absolute (3S) configuration of (+) enantiomers of 1 and 2 was determined by comparison of their eluation profile to that of (±)‐3 and (3S)‐(+)‐3, taking into account relative (ψa or ψe) configuration of the prevailing conformer in solution. Chirality 14:12–17, 2002. © 2002 Wiley‐Liss, Inc.
Enantiopure building blocks for chiral drugs from racemic mixtures of secondary alcohols by combination of lipase catalysis and Mitsunobu esterification
Authors: Liu Hui‐Ling , Anthonsen Thorleif
Published: September 2002

The racemic alcohols 3‐chloro‐1‐(2‐thienyl)‐1‐propanol, 3‐chloro‐1‐phenylpropanol, and 1‐chloro‐3‐(3,4‐difluorophenoxy)‐2‐propanol were converted into a mixture of one enantiomer as butanoate and the other as alcohol by lipase catalysis. Subsequent Mitsunobu esterification without separation proceeded with inversion of the unreacted alcohols to give high yield and ee of the three enantiopure butanoates. The butanoates of opposite configuration were produced in a similar manner, but starting with lipase‐catalyzed hydrolysis of the racemic butanoates. Chirality 14: 25–27, 2002. © 2002 Wiley‐Liss, Inc.
C2‐Symmetric dialkoxyphosphoramide and dialkoxythiophosphoramide derivatives of (1R, 2R)‐1,2‐diaminocyclohexane as chiral ligands for the titanium(IV) alkoxide‐promoted asymmetric addition reactions of diethylzinc to arylaldehydes
Authors: Shi Min , Wu Xiao‐Feng , Rong Guobin
Published: September 2002

C2‐Symmetric chiral diethoxyphosphoramide 4, diethoxythiophosphoramide 5, and diisopropoxyphosphoramide 6 of (1R, 2R)‐1,2‐diaminocyclohexane were prepared by the reactions of diethoxyphosphinic chloride, diethoxythiophosphinic chloride, and diisopropoxyphosphinic chloride with (1R, 2R)‐1,2‐diaminocyclohexane, respectively. They were used as catalytic chiral ligands in the asymmetric addition reactions of diethylzinc to aldehydes in the presence of titanium(IV) isopropoxide to give the corresponding sec‐alcohols with 43–70% ee. Chiral ligands 4 and 5 gave the sec‐alcohols with opposite absolute configuration. Chirality 14:90–95, 2002. © 2002 Wiley‐Liss, Inc.
Enantioselectivity of the musk odor sensation
Authors: Kraft Philip , Fráter Georg
Published: September 2002

This brief review, the summary of a talk at the Symposium on Biological Chirality 2000 in Szeged, Hungary, illustrates what chiral recognition tells us about the molecular parameters of the musk odor sensation. While the enantioselectivity of odor perception is strong evidence for the key role of proteinogenic receptors in the molecular mechanism of olfaction, the quantitative and qualitative odor differences of enantiomers are often not very pronounced, as in the case of muscone (17/26). In those cases, however, where there is strong enantiodiscrimination, we find most intense musk odorants with very low odor thresholds, such as (–)‐(12R)‐12‐methyl‐9‐oxa‐14‐tetradecanolide (35), (12R;9Z)‐12‐methyl‐14‐tetradec‐9‐enolide [(R)‐Nirvanolide®, 38], and (–)‐(4S;7R)‐1,3,4,6,7,8‐hexahydro‐4,6,6,7,8,8‐hexamethylcyclopenta[g]‐2‐benzopyran [(–)‐(4S;7R)‐Galaxolide®, 57], the latter being rather rigid. We thus can assume the geometry of the musk receptor to be fairly complementary to these compounds, which therefore can serve as templates for the design of new musk odorants. Chirality 13:388–394, 2001. © 2001 Wiley‐Liss, Inc.
Chirality and symmetry aspects of spheroarenes, including fullerenes
Authors: Rassat André
Published: September 2002

The design of the smallest spheroarenes (CN molecules based on trivalent polyhedral framework, a class which subsumes fullerenes) of any point‐group symmetry is presented. The role of Curie's principle is discussed. Some molecules whose carbon backbone is a nonplanar graph are described. Chirality 13:395–402, 2001. © 2001 Wiley‐Liss, Inc.
Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods
Authors: Trapp Oliver , Schoetz Gabriele , Schurig Volker
Published: September 2002

In recent years, dynamic chromatography and stopped‐flow chromatographic techniques have become versatile tools for the determination of enantiomerization and isomerization barriers. Increasing demands for the stereochemical safety of chiral drugs contributed to the rapid development of new techniques. New computer‐aided evaluation systems allow the on‐line determination of interconversion barriers from the experimental chromatograms. Both dynamic chromatography and stopped‐flow chromatography have been applied to the entire range of chromatographic methods (GC, SFC, HPLC, CE). Chirality 13:403–414, 2001. © 2001 Wiley‐Liss, Inc.
Variable stereochemistry in highly branched isoprenoids from diatoms
Authors: Belt Simon T. , Allard W. Guy , Johns Lesley , König Wilfried A. , Massé Guillaume , Robert Jean‐Michel , Rowland Steve
Published: September 2002

C25 highly branched isoprenoid (HBI) alkenes are ubiquitous lipids found in geochemical samples around the globe. The origins of these widespread geochemicals are believed to be restricted to a limited number of diatoms, including Haslea ostrearia (and related species), Rhizosolenia setigera, and Pleurosigma intermedium. The unsaturation of the HBI alkenes ranges from 2–6 in different species and cultures. The number of stereogenic centres is usually limited to two in the HBI alkenes due to double bond positions. The relative and/or absolute configurations for these have been determined for a range of HBI alkenes produced from different diatoms cultured under a number of growth conditions. These determinations have involved a combined spectroscopic and chromatographic analysis using NMR spectroscopy and chiral gas chromatography, respectively. HBIs isolated from Haslea spp. belong to a specific structural type which exhibit configurational diastereoisomerism, while those isolated from P. intermedium and R. setigera represent a different structural type and usually exist as mixtures of geometric isomers only. HBIs are reported from a new species of diatom whose stereochemical properties lie between those found for Haslea spp. and P. intermedium. Chirality 13:415–419, 2001. © 2001 Wiley‐Liss, Inc.
Coupling from AII amacrine cells to ON cone bipolar cells is bidirectional
Authors: Trexler E. Brady , Li Wei , Mills Stephen L. , Massey Stephen C.
Published: September 2002

The AII amacrine cell is a critical interneuron in the rod pathway of the mammalian retina. Rod signals pass into cone pathways by means of gap junctions between AII amacrine cells and ON cone bipolar cells. Filling AII amacrine cells with Neurobiotin produces labeling of cone bipolar cells by means of these gap junctions. However, tracer injections into bipolar cells do not produce labeling of the AII network (Vaney [1997] Invest Ophthalmol Vis Sci. 38:267–273), which suggests that the AII/bipolar gap junctions allow the passage of tracer in only one direction. This mechanism stands in contrast to physiological results, which indicate that light adapted signals can pass from ON cone bipolar cells into the AII network (Xin and Bloomfield [1999] Vis Neurosci. 16:653–665). Here, we report that a variety of ON and OFF bipolar cells are sometimes anomalously coupled to the A‐type horizontal cell network. These relatively rare examples do not result from dye injection errors, but seem to represent minor developmental errors. However, this provides a method to obtain Neurobiotin‐filled cone bipolar cells without the necessity of impaling them with a microelectrode. Under these conditions, Neurobiotin spreads from ON cone bipolar cells into neighboring AII amacrine cells. The dye‐coupled AII amacrine cells, positively identified by double labeling with an antibody against calretinin, were centered around anomalously coupled ON bipolar cells. These results indicate that AII/bipolar cell gap junctions allow tracer coupling in both directions, consistent with previous physiological results. The previous failure to detect the passage of neuronal tracer from injected bipolar cells to AII amacrine cells may reflect electrode damage or perhaps the asymmetrical voltage sensitivity of a heterotypic gap junction. J. Comp. Neurol. 437:408–422, 2001. © 2001 Wiley‐Liss, Inc.
Morphology, electrophysiology, and calbindin immunoreactivity of myenteric neurons in the guinea pig distal colon
Authors: Tamura Kenji , Ito Hiroyuki , Wade Paul R.
Published: September 2002

The morphological and physiological characteristics of myenteric neurons in the guinea pig distal colon were determined using Lucifer yellow‐ or N‐(2‐aminoethyl) biotinamide‐containing microelectrodes and intracellular recording and staining methods. The neurons in this study (n = 204) were classified on the basis of the shapes of their cell bodies and short processes or dendrites and the number of long processes or axons as Dogiel type I (n = 75 neurons; 36.8%), filamentous (n = 31 neurons; 15.2%), Dogiel type II (n = 38 neurons; 18.6%), and unclassified (n = 60 neurons; 29.4%). All Dogiel type II neurons had action potentials followed by an after‐spike hyperpolarization (AH), and most of them (84%) had large, smooth somata and filamentous, short processes in addition to multiple, long processes or axons. Most of Dogiel type I, filamentous, and unclassified neurons (98%) had a single, long process, but four Dogiel type I neurons and one unclassified neuron had two long processes terminating as varicosities within other ganglia or on the surface of longitudinal muscle. The projections of monoaxonal neurons were distributed equally between oral and aboral directions, and most of them received fast excitatory postsynaptic potentials (EPSPs). All of the Dogiel type II neurons and seven Dogiel type I neurons were positive for calbindin immunoreactivity, but three filamentous neurons received fEPSPs, had spikes followed by AH, and were negative for calbindin. The presence of calbindin‐immunoreactive(‐IR) neurons was quite variable among the ganglia. These results confirm that neither the presence of calbindin immunoreactivity nor the absence of fEPSPs can be used as a predictor of cellular morphology or electrophysiological properties of myenteric neurons in the distal colon. J. Comp. Neurol. 437:423–437, 2001. © 2001 Wiley‐Liss, Inc.
Development of GABA‐immunoreactive neuron patterning in the spinal cord
Authors: Binor Elaine , Heathcote R. David
Published: September 2002

In the frog Xenopus laevis, γ‐aminobutyric acid (GABA)‐immunoreactive spinal cord neurons (Kolmer‐Agduhr cells) formed a dispersed pattern within two columns on either side of the midline. The cellular pattern became established during embryonic and larval development. The GABA‐immunoreactive cells are cerebrospinal fluid (CSF)‐contacting neurons that began to appear by 1.2 days (st 26) of development. This stage occurred shortly after neural tube closure (0.9 days, st 21) and followed the appearance of ultrastructural characteristics of CSF‐contacting neurons. The pattern of GABA‐immunoreactive cells emerged during embryogenesis, as their density increased. Each longitudinal column was heterogeneous, containing cells with and without GABA immunoreactivity. Spatial analysis at several embryonic and larval stages showed that the cells in each column formed a nonrandom, dispersed pattern even at early stages of differentiation. This one‐dimensional pattern resembled that of dopamine‐immunoreactive neurons, which are also located in the ventral spinal cord. The patterning of both cell types followed a different time course, but the ultimate spacing of the neurons remained comparable. These results suggested that the mechanism patterning the two cell types within the same region was similar but not identical and may involve related molecular mechanisms. J. Comp. Neurol. 438:1–11, 2001. © 2001 Wiley‐Liss, Inc.
Distribution of substance P and neurokinin‐1 receptor immunoreactivity in the suprachiasmatic nuclei and intergeniculate leaflet of hamster, mouse, and rat
Authors: Piggins Hugh D. , Samuels Rayna E. , Coogan Andrew N. , Cutler David J.
Published: September 2002

The circadian pacemaker in the hypothalamic suprachiasmatic nuclei (SCN) receives photic information directly via the retinohypothalamic tract (RHT) and indirectly from retinally innervated cells in the thalamic intergeniculate leaflet (IGL) that project to the SCN. Using standard immunohistochemical methods, we examined the presence and distribution of substance P (SP) and the neurokinin‐1 receptor (NK‐1) in the SCN and IGL of rat and determined whether the patterns of immunostaining generalized to the SCN and IGL of Syrian hamster, Siberian hamster, and mouse. Terminals immunoreactive for SP were sparse within the SCN of Siberian and Syrian hamsters and mouse but were intense in the ventral, retinally innervated portion of the rat SCN. Immunostaining for the NK‐1 receptor was mainly absent from the SCN of hamster and mouse. In contrast, a plexus of NK‐1‐ir cells and processes that was in close proximity to SP‐ir terminals was found in the ventral SCN of the rat. Substance P‐ir terminals were observed in the IGL of all four species, as were NK‐1‐ir cells and fibres. Double‐labelled IGL sections of hamster or rat revealed SP‐ir terminals in close apposition to NK‐1‐immunostained cells and/or fibres. These data indicate that SP could be a neurotransmitter of the RHT in rat, but not in hamster or in mouse, and they highlight potential species differences in the role of SP within the SCN circadian pacemaker. Such species differences do not appear to exist at the level of the IGL, where SP‐ir and NK‐1‐ir were similar in all species studied. J. Comp. Neurol. 438:50–65, 2001. © 2001 Wiley‐Liss, Inc.
Time step selection for shock problems
Authors: Hörnell Karl , Lötstedt Per
Published: September 2002

The solution to a conservation law is integrated in time by an explicit embedded Runge–Kutta method. The time steps are chosen so that a bound on the local error is satisfied. At discontinuities such as shocks in the solution the time step is too pessimistic. By filtering the error estimate the time steps are determined by the smooth parts of the solution. The technique is justified theoretically and in numerical experiments. Copyright © 2001 John Wiley & Sons, Ltd.