bluuebunny/crossref_metadata_2025 huggingface dataset:
Specific Solvation as a Tool for the N‐Chemoselective Arylsulfonylation of Tyrosine and (4‐Hydroxyphenyl)glycine Methyl Esters
Authors: Penso Michele , Albanese Domenico , Landini Dario , Lupi Vittoria , Tricarico Giovanni
Published: November 2003

The methyl esters of L‐tyrosine and D‐(4‐hydroxyphenyl)glycine were directly transformed into the corresponding 2‐arylsulfonamido esters with arylsulfonyl chlorides, without protecting the phenolic hydroxy group. The reaction is conducted in a THF/DMF (8:1) mixture as solvent, and using lyophilized solid sodium carbonate as base. The N‐arylsulfonylation takes place with good yields (62−85%) in a chemoselective fashion, without racemization of the stereogenic carbon centers. The DMF (2.6 mol/mol amino ester) specifically solvates the oxygen atom of the formed N,O‐dianion, reducing its nucleophilicity and dramatically increasing the chemoselectivity of the N‐substitution. In contrast, in the absence of a highly coordinating additive, the phenoxide anion competes unfavorably with the 2‐amino group for the nucleophilic attack, and the N,O‐disulfonyl esters are produced with relevant yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
2‐C‐Formyl Glycals: Emerging Chiral Synthons in Organic Synthesis
Authors: Ramesh Namakkal G. , Balasubramanian Kalpattu K.
Published: November 2003

Naturally occurring carbohydrates and their derivatives have been useful during the last few decades as “chiral pool” constituents in the enantioselective synthesis of biologically active natural and non‐natural products. The ready availability of a wide range of carbohydrates in nature and their multichiral architecture, coupled with their well defined stereochemistry, make them attractive starting materials in organic synthesis. The synthesis of key intermediates by incorporation of suitable functional groups onto carbohydrates, which can then be further exploited, has always been a challenging task. In this context, 2‐C‐formyl glycals, a new class of carbohydrates incorporating an α,β‐unsaturated carbonyl system, have recently emerged as potential synthons for numerous organic transformations. Four different syntheses of 2‐C‐formyl glycals have been reported so far. However, the importance of 2‐C‐formyl glycals has become well established after our development of a more general, one‐step synthesis, employing the well known Vilsmeier−Haack reaction. Synthetic transformations of these 2‐C‐formyl glycals have resulted in a variety of new compounds of significant synthetic and biological interest. 2‐C‐Formyl glycals have been shown to be ideal substrates for chemo‐, regio‐ and stereoselective glycosidation, nucleophilic addition/substitution and cycloaddition reactions. The reported syntheses and applications of these important “chiral intermediates” are presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Preparation of [1,2,3,4,5‐13C5]‐5‐Amino‐4‐oxopentanoic Acid (ALA) − Design of a Synthetic Scheme to Prepare Any 13C‐ and 15N‐Isotopomer with High Isotopic Enrichment
Authors: Shrestha‐Dawadi Prativa Bade , Lugtenburg Johan
Published: November 2003

5‐Amino‐4‐oxopentanoic acid (5‐aminolevulinic acid) is a precursor in the biosynthesis of the biologically active porphyrins such as chlorophyll, bacteriochlorophyll, heme, etc. These systems are central in photosynthesis, oxygen transport, electron transport, etc. In this paper we describe a simple scheme to prepare any isotopomer of 5‐aminolevulinic acid in a few steps in high yield. Using a similar scheme, levulinic acid can now also be prepared in any isotopomeric form. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Voltammetric Determination of N,N‐Dimethyl‐4‐amine‐carboxyazobenzene at a Silver Solid Amalgam Electrode
Authors: Barek Jirí , Dodova Elena , Navrátil Tomáš , Yosypchuk Bogdan , Novotný Ladislav , Zima Jirí
Published: November 2003

The voltammetric behavior of N,N‐dimethyl‐4‐amino‐2′‐carboxyazobenzene was investigated by differential pulse voltammetry (DPV) at a mercury meniscus‐modified silver solid amalgam electrode (m‐AgSAE). Conditions have been found for its determination by DPV at m‐AgSAE in the concentration range of 0.4 to 15 μmol L−1.
Electrochemical Oxidation of Quercetin
Authors: Brett Ana Maria Oliveira , Ghica Mariana‐Emilia
Published: November 2003

The mechanism of electrochemical oxidation of quercetin on a glassy carbon electrode has been studied using cyclic, differential pulse and square‐wave voltammetry at different pH. It proceeds in a cascade mechanism, related with the two catechol hydroxyl groups and the other three hydroxyl groups which all present electroactivity, and the oxidation is pH dependent. Quercetin also adsorbs strongly on the electrode surface; and the final oxidation product is not electroactive and blocks the electrode surface. The oxidation of the catechol 3′,4′‐dihydroxyl electron‐donating groups, occurs first, at very low positive potentials, and is a two electron two proton reversible reaction. The hydroxyl group oxidized next was shown to undergo an irreversible oxidation reaction, and this hydroxyl group can form a intermolecular hydrogen bond with the neighboring oxygen. The other two hydroxyl groups also have an electron donating effect and their oxidation is reversible.
Geometry‐based directional model for mobile radio channels—principles and implementation
Authors: Molisch Andreas F. , Kuchar Alexander , Laurila Juha , Hugl Klaus , Schmalenberger Ralph
Published: November 2003

Adaptive antennas are used in mobile radio systems for improving coverage and increasing capacity. For realistic system design and simulation, channel models are required in order to assess the performance of such systems. We propose the so‐called ‘geometry‐based stochastic channel model’ (GSCM), which is easy to implement and has a low complexity even when the directional dimension of the channel is taken into account. In this model, we prescribe the probability density function (PDF) of the location of the scatterers. From this, the angularly resolved impulse response can be computed by a simple ray tracing. We then present various extensions of the model in urban environments, namely for diffraction losses and wave guiding by street canyons. We also discuss methods for efficiently implementing GSCM. Copyright © 2003 AEI.
Constituents of the essential oil of Hemerocallis ﬂava day lily
Authors: Lin Ping , Cai Jibao , Li Jun , Sang Wenqiang , Su Qingde
Published: November 2003

Volatile oil of Hemerocallis ﬂava, the day lily, was obtained by simultaneous distillation–solvent extraction (SDE). Following, the essential oil was analysed by gas chromatography (GC) and gas chromatography–mass spectrumetry (GC–MS). Fifty‐one components were identiﬁed, constituting approximately 92% of the oil. The main constituents of the essential oil were 3‐furanmethanol (47.9%) and 2‐furancarboxaldehyde (10.4%). Copyright © 2003 John Wiley & Sons, Ltd.
Sum statistics for the joint detection of multiple disease loci in case‐control association studies with SNP markers
Authors: Wille Anja , Hoh Josephine , Ott Jurg
Published: November 2003

In complex traits, multiple disease loci presumably interact to produce the disease. For this reason, even with high‐resolution single nucleotide polymorphism (SNP) marker maps, it has been difficult to map susceptibility loci by conventional locus‐by‐locus methods. Fine mapping strategies are needed that allow for the simultaneous detection of interacting disease loci while handling large numbers of densely spaced markers. For this purpose, sum statistics were recently proposed as a first‐stage analysis method for case‐control association studies with SNPs. Via sums of single‐marker statistics, information over multiple disease‐associated markers is combined and, with a global significance value α, a small set of “interesting” markers is selected for further analysis. Here, the statistical properties of such approaches are examined by computer simulation. It is shown that sum statistics can often be successfully applied when marker‐by‐marker approaches fail to detect association. Compared with Bonferroni or False Discovery Rate (FDR) procedures, sum statistics have greater power, and more disease loci can be detected. However, in studies with tightly linked markers, simple sum statistics can be suboptimal, since the intermarker correlation is ignored. A method is presented that takes the correlation structure among marker loci into account when marker statistics are combined. Genet Epidemiol 25:350–359, 2003. © 2003 Wiley‐Liss, Inc.
Rank truncated product of P‐values, with application to genomewide association scans
Authors: Dudbridge Frank , Koeleman Bobby P.C.
Published: November 2003

Large exploratory studies are often characterized by a preponderance of true null hypotheses, with a small though multiple number of false hypotheses. Traditional multiple‐test adjustments consider either each hypothesis separately, or all hypotheses simultaneously, but it may be more desirable to consider the combined evidence for subsets of hypotheses, in order to reduce the number of hypotheses to a manageable size. Previously, Zaykin et al. ([2002] Genet. Epidemiol. 22:170–185) proposed forming the product of all P‐values at less than a preset threshold, in order to combine evidence from all significant tests. Here we consider a complementary strategy: form the product of the K most significant P‐values. This has certain advantages for genomewide association scans: K can be chosen on the basis of a hypothesised disease model, and is independent of sample size. Furthermore, the alternative hypothesis corresponds more closely to the experimental situation where all loci have fixed effects. We give the distribution of the rank truncated product and suggest some methods to account for correlated tests in genomewide scans. We show that, under realistic scenarios, it provides increased power to detect genomewide association, while identifying a candidate set of good quality and fixed size for follow‐up studies. Genet Epidemiol 25:360–366, 2003. © 2003 Wiley‐Liss, Inc.
Multipoint linkage disequilibrium mapping for complex diseases
Authors: Liang Kung‐Yee , Hsu Fang‐Chi , Beaty Terri H.
Published: November 2003

Linkage disequilibrium (LD) or association studies using case‐parent trios have become a common approach to locate unobserved susceptibility genes underlying complex diseases. With the availability of ever more dense marker maps, how to utilize the information carried by multiple markers simultaneously remains challenging. Recently, Liang et al. ([2001a] Am. J. Hum. Genet. 68: 937–950) proposed a multipoint LD method to estimate the location of a susceptibility gene within a framework map along with its sampling uncertainty. Two important features of this method are that 1) it uses all trios whether parents are heterozygous for a given marker or not, and 2) it provides a single test statistic for the null hypothesis of no linkage or no LD to the region, avoiding the multiple testing problem encountered when performing individual transmission disequilibrium tests (TDT) for each marker individually. In this paper, we discuss how this method can be expanded to address important issues pertaining to complex diseases in a unified fashion. These issues include, among others, gene‐gene and gene‐environment interactions, genetic heterogeneity, phenotypic refinement, and paternal vs. maternal transmission. We applied this method to asthmatic case‐parent trios from the Collaborative Study on the Genetics of Asthma (CSGA), and found that the previous evidence for linkage and LD in a 13.6 cM region of chromosome 11 can be attributed to maternal transmission, while there was no evidence of excess paternal transmission. Furthermore, such discrepancy in preferential transmission was most evident among probands with early onset age (6 years old or younger).Genet Epidemiol25:285–292, 2003. © 2003 Wiley‐Liss, Inc.
Genistein treatment protects mice from ionizing radiation injury
Authors: Landauer Michael R. , Srinivasan Venkataraman , Seed Thomas M.
Published: November 2003

The radioprotective and behavioral effects of an acute administration of the isoﬂavone genistein (4′,5,7‐trihydroxyﬂavone) were investigated in adult CD2F1 male mice. Mice were administered a single subcutaneous (s.c.) dose of genistein either 24 h or 1 h before a lethal dose of gamma radiation (9.5‐Gy of cobalt‐60 at 0.6 Gy min−1). Mice received saline, PEG‐400 vehicle or genistein at 3.125, 6.25, 12.5, 25, 50, 100, 200, or 400 mg kg−1 body weight. For mice treated 24 h before irradiation there was a signiﬁcant increase in 30‐day survival for animals receiving genistein doses of 25 to 400 mg kg−1 (p < 0.001). In contrast, the 30‐day survival rates of mice treated with genistein 1 h before irradiation were not signiﬁcantly different from those of the vehicle control group. Additionally, the acute toxicity of genistein was evaluated in non‐irradiated male mice administered a single s.c. injection of saline, vehicle, or genistein at 100, 200 or 400 mg kg−1. At these genistein doses there were no adverse effects, compared with controls, on locomotor activity, grip strength, motor coordination, body weight, testes weight, or histopathology. These results demonstrate that a single s.c. administration of the ﬂavonoid genistein at non‐toxic doses provides protection against acute radiation injury. Published in 2003 by John Wiley & Sons, Ltd.
Developmental toxicity evaluation of inhaled tertiary amyl methyl ether in mice and rats
Authors: Welsch Frank , Elswick Barbara , Arden James R. , Marr Melissa C. , Myers Christina B. , Tyl Rochelle W.
Published: November 2003

This evaluation was part of a much more comprehensive testing program to characterize the mammalian toxicity potential of the gasoline oxygenator additive tertiary amyl methyl ether (TAME), and was initiated upon a regulatory agency mandate. A developmental toxicity hazard identiﬁcation study was conducted by TAME vapor inhalation exposure in two pregnant rodent species. Timed‐pregnant CD®(Sprague‐Dawley) rats and CD‐1® mice, 25 animals per group, inhaled TAME vapors containing 0, 250, 1500 or 3500 ppm for 6 h a day on gestational days 6–16 (mice) or 6–19 (rats). The developmental toxicity hazard potential was evaluated following the study design draft guidelines and end points proposed by the United States Environmental Protection Agency. Based on maternal body weight changes during pregnancy, the no‐observable‐adverse‐effect level (NOAEL) was 250 ppm for maternal toxicity in rats and 1500 ppm for developmental toxicity in rats using the criterion of near‐term fetal body weights. In mice, more profound developmental toxicity was present than in rats, at both 1500 and 3500 ppm. At the highest concentration, mouse litters revealed more late fetal deaths, signiﬁcantly reduced fetal body weights per litter and increased incidences of cleft palate (classiﬁed as an external malformation), as well as enlarged lateral ventricles of the cerebrum (a visceral variation). At 1500 ppm, mouse fetuses also exhibited an increased incidence of cleft palate and the dam body weights were reduced. Therefore, the NOAEL for the mouse maternal and developmental toxicity was 250 ppm under the conditions of this study. Copyright © 2003 John Wiley & Sons, Ltd.
Phosphoric and boric acid activation of pine sawdust
Authors: Muñoz Yuvisa , Arriagada Renán , Soto‐Garrido G , García Rafael
Published: November 2003

Chemical activation of pine sawdust using aqueous solutions of phosphoric and boric acid was studied. Thermogravimetric analyses of the impregnated lignocellulosic precursor as well as their reactivities are presented. The role of the activating agents in the thermal decomposition of the precursor and their effects on the development of porosity in activated carbons is discussed. The use of boric acid as activating agent and a final heat treatment temperature (HTT) of 600 °C produced some porosity and activated carbons with a surface area of 600 m2 g−1. With a HTT of 450 °C, molecular sieve‐like materials were produced. In contrast, phosphoric acid activation produced activated carbons with high surface areas. The amount of phosphoric acid retained in the precursor was, as expected, a function of the initial concentration as well as the impregnation time and temperature. The fact that the activated carbon porosity increases with the phosphoric acid content per gram of precursor was confirmed. The use of 6 M phosphoric acid solution and HTT of 450 °C produced the activated carbon with the highest surface area, about 1600 m2 g−1. The high degree of microporosity which developed in phosphoric acid‐activated carbons is related to the low reactivity during the thermal treatment of chemical activation. The presence of up to 10% oxygen during HTT with phosphoric acid activation caused only small textural changes. Copyright © 2003 Society of Chemical Industry
Direct filtration of Procion dye bath wastewaters by nanofiltration membranes: flux and removal characteristics
Authors: Koyuncu Ismail
Published: November 2003

The treatment and reuse of industrial wastewaters by membrane processes has become more attractive in the last few years due to constraints on water usage. The aim of this study was to investigate the direct filtration of reactive dye house wastewaters by nanofiltration membranes based on permeate flux, and sodium chloride and colour removal. Experiments were performed using both synthetic and industrial dye bath wastewaters with the fluxes of the industrial dye bath wastewaters lower than those of the synthetic solutions. The effects of operating conditions such as pressure and pH were assessed. Studies with DS5 DK type (polysulfone–polyamide) membranes showed that nanofiltration membranes are suitable for direct treatment of wastewaters and the permeate quality was appropriate for reuse in the dyeing process. Pre‐treatment and neutralisation were important for recovery of large amounts of salt and water from the permeate stream. Neutralisation of the solution with HCl rather than H2SO4 gave a better permeate from the point of view of the reuse. The highest permeate flux and colour removal and the lowest salt removal were achieved with the HCl neutralisation. Copyright © 2003 Society of Chemical Industry
Mineralization improvement of phenol aqueous solutions through heterogeneous catalytic ozonation
Authors: Beltrán Fernando J , Rivas Francisco J , Montero‐de‐Espinosa Ramón
Published: November 2003

To assess the mineralization level achieved, aqueous solutions of phenol have been treated with ozone in the presence of different solid catalysts. Activated carbon was the principal catalyst investigated, although some additional experiments were carried out by utilizing metal oxide‐based catalysts (ie Ti, Co and Fe) supported onto alumina. Usage of Co/Al2O3 led to the highest values of phenol byproduct mineralization, nevertheless some metal leaching was experienced in the process. The operating variables studied when using activated carbon as the catalyst were ozone gas concentration, amount of catalyst added and temperature. Regardless of the catalyst type used, two different ozonation kinetic regimes were observed: (I) an initial period, corresponding to the presence of phenol in solution, characterized by small amounts of dissolved ozone and no improvement of the mineralization degree if comparing catalytic and non‐catalytic runs; (II) a second period, free of phenol, in which dissolved ozone accumulated in water and the beneficial effects of catalysts on mineralization were noticed. Experimental data also demonstrated the improvement in oxalic acid elimination in the presence of heterogeneous catalysts. Finally, consumption of ozone per mass of carbon removed, reaction factors and Hatta numbers were also calculated. Copyright © 2003 Society of Chemical Industry
Fluorine‐18‐ and iodine‐125‐labelling of spiegelmers
Authors: Kuhnast B. , Klussmann S. , Hinnen F. , Boisgard R. , Rousseau B. , Fürste J. P. , Tavitian B. , Dollé F.
Published: November 2003

Spiegelmers are high‐affinity l‐enantiomeric oligonucleotide ligands (aptamers) that display high resistance to enzymatic degradation compared to d‐oligonucleotides. Spiegelmers belong to the third generation of aptamers, and are currently extensively investigated as potential therapeutic agents. We have previously developed an original method to label natural oligonucleotides with radiohalogens and particularly with fluorine‐18, the most widely used positron‐emitter, t1/2: 109.8 min. Using the same strategy, we herein report the labelling of Spiegelmers, both with fluorine‐18 for positron emission tomography imaging and iodine‐125 for high resolution autoradiography. Three 25‐mer l‐oligonucleotides have been used, differing (a) by the position of the terminal phosphorothioate monoester group (3′‐ or 5′‐end, and therefore differing by the position of the labelling on the macromolecule) and (b) by the nature of the backbone sugar moiety (2′‐OH or 2′‐H, therefore covering the RNA and DNA series, respectively). N‐(4‐[18F]fluorobenzyl)‐2‐bromoacetamide was synthesized in three radiochemical steps from 4‐cyano‐N,N,N‐trimethylanilinium trifluoromethanesulfonate and HPLC‐purified in 90 min (typical production: 2.2–2.4 GBq starting from a batch of 22–24 GBq of [18F]fluoride). N‐(4‐[125I]iodobenzyl)‐2‐bromoacetamide was synthesized from the corresponding trimethylsilyl derivative (one pot, two radiochemical steps) and HPLC‐purified in 60 min (typical production: 24 MBq starting from 37 MBq of Na[125I]I). Coupling of the Spiegelmers with the appropriate HPLC‐purified [radiolabelled]‐halobenzyl‐2‐bromoacetamide (MeOH/PBS (0.1 M, pH 8), 10 min, 120°C) gave the corresponding labelled conjugated Spiegelmers after RP‐HPLC purification. For fluorine‐18, the whole synthetic procedure yields up to 1.1 GBq of pure labelled Spiegelmers in 160 min with a specific radioactivity of 37–74 GBq/μmol at the end of synthesis starting from 22–24 GBq of [18F]fluoride. For iodine‐125, the whole synthetic procedure allows producing up to 7.4 MBq of pure labelled Spiegelmers in 100 min with a specific radioactivity of 11–37 GBq/μmol starting from 37 MBq of Na[125I]I. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis of [3H] vardenafil, Levitra®, using a new labeling technique
Authors: Pleiss U.
Published: November 2003

Tritium was introduced into the new orally active, selective phosphodiesterase type V (PDE V) inhibitor vardenafil (Levitra®), by reduction of a suitable amide precursor with freshly prepared lithium aluminum tritide. A specific activity of 52.7 Ci/mmol (1.95 TBq/mmol) was achieved. In order to overcome the usual technical difficulties during the preparation of complex tritides a new and easy labeling technique which has considerable potential for various tritia‐tion procedures, was developed. Copyright © 2003 John Wiley & Sons, Ltd.
Radiosynthesis of 3‐(2′‐[18F]fluoro)‐flumazenil ([18F]FFMZ)
Authors: Wadsak Wolfgang , Mitterhauser Markus , Mien Leonhard‐Key , Tögel Stefan , Keppler Bernhard , Dudczak Robert , Kletter Kurt
Published: November 2003

Recently, two fluorine‐18 labelled derivatives of flumazenil were described: 5‐(2′‐[18F]fluoroethyl)‐5‐desmethylflumazenil (ethyl 8‐fluoro‐5‐[18F]fluoroethyl‐6‐oxo‐5,6‐dihydro‐4H‐benzo‐[f]imidazo[1,5‐a] [1,4]diazepine‐3‐carboxylate; [18F]FEFMZ) and 3‐(2′‐[18F]fluoro)‐flumazenil (2′‐[18F]fluoroethyl 8‐fluoro‐5‐methyl‐6‐oxo‐5,6‐dihydro‐4H‐benzo‐[f]imidazo[1,5‐a]‐[1,4]diazepine‐3‐carbo‐ xylate; [18F]FFMZ). Since the biodistribution data of the latter were superior to those of the former we developed a synthetic approach for [18F]FFMZ starting from a commercially available precursor, thereby obviating the need to prepare a precursor by ourselves. The following two‐step procedure was developed:

First, [18F]fluoride was reacted with 2‐bromoethyl triflate using the kryptofix/acetonitrile method to yield 2‐bromo‐[18F]fluoroethane ([18F]BFE). In the second step, distilled [18F]BFE was reacted with the tetrabutylammonium salt of 3‐desethylflumazenil (8‐fluoro‐5‐methyl‐6‐oxo‐5,6‐dihydro‐4H‐benzo‐[f]imidazo[1,5‐a] [1,4]diazepine‐3‐carboxylic acid) to yield [18F]FFMZ. The synthesis of [18F]FFMZ allows for the production of up to 7 GBq of this PET‐tracer, enough to serve several patients. [18F]FFMZ synthesis was completed in less than 80 min and the radiochemical purity exceeded 98%. Copyright © 2003 John Wiley & Sons, Ltd.
Measurement of single‐kidney glomerular filtration rate using a contrast‐enhanced dynamic gradient‐echo sequence and the Rutland‐Patlak plot technique
Authors: Hackstein Nils , Heckrodt Jan , Rau Wigbert S.
Published: November 2003

Purpose

To determine the accuracy of single‐kidney glomerular filtration rate (GFR) determination using contrast‐enhanced dynamic magnetic resonance imaging (MRI) and the Rutland‐Patlak plot technique.

Materials and Methods

Twenty‐eight adult patients were included. As reference method, the GFR was measured by plasma clearance using a small bolus injection of iopromide. A three‐dimensional gradient‐echo (GRE) sequence with a flip angle of 50° was used for MRI; this showed a good linear relationship between gadolinium (Gd)‐DTPA concentration and signal change when measured up to a Gd‐DTPA concentration of 10 mmol/liter. A slab containing both kidneys and the abdominal aorta was measured 30 times in approximately 3.5 minutes. During this measurement, 15 mL of Gd‐DTPA, 0.5 mol/liter diluted to a volume of 60 mL, was injected over 60 seconds. A Rutland‐Patlak plot was calculated from the signal changes in the aorta and the renal parenchyma. Single‐kidney GFR was calculated for different time windows from the Rutland‐Patlak plot slope.

Results

The best correlation compared to the reference method was found with the GFR calculated from the slope of the Rutland‐Patlak plot 40–110 seconds postaortic rise. Pearson's correlation coefficient was r = 0.86, SD was 14.8 mL/minute. In many of the patients, a decrease of the renal signal was observed in the excretory phase, which was probably caused by very high Gd‐DTPA concentrations in the collecting tubules.

Conclusion

Single‐kidney GFR can be calculated from dynamic contrast‐enhanced MRI. We found a promising correlation of global GFR calculated by MRI compared to the reference method. In any future study, the amount of Gd‐DTPA should by reduced to avoid artificial signal drop in the excretory phase induced by the T2* effect. J. Magn. Reson. Imaging 2003;18:714–725. © 2003 Wiley‐Liss, Inc.
Multislice T1 relaxation time measurements in the brain using IR‐EPI: Reproducibility, normal values, and histogram analysis in patients with multiple sclerosis
Authors: van Walderveen Marianne A.A. , van Schijndel Ronald A. , Pouwels Petra J.W. , Polman Chris H. , Barkhof Frederik
Published: November 2003

Purpose

To perform T1 measurements using inversion recovery (IR) echoplanar imaging (EPI) to evaluate reproducibility, normal values, and T1 histogram analysis as a measure of disease progression in multiple sclerosis (MS) patients.

Materials and Methods

Multislice IR‐EPI was performed in 10 controls and 36 MS patients. Region‐of‐interest (ROI) and T1 histogram analysis were performed on T1 maps and compared to hypointense T1 lesions and brain atrophy in MS patients.

Results

Coefficient of variation (COV) varied from 1.6% to 4.9%. Callosal normal (appearing) white matter (N(A)WM) showed the lowest and cortical gray matter the highest T1 values. T1 histogram analysis in controls showed a sharp WM peak centered on a T1 value of 729 msec (range = 679–765) with extension into a shoulder of higher T1 values. In MS patients, a shift toward higher T1 values (mean = 788 msec, range = 700–957) with a lower relative peak amplitude was present, predominantly resulting from T1 prolongation in NAWM. T1 histogram parameters strongly related to hypointense T1 lesion volume and brain atrophy in MS patients.

Conclusions

IR‐EPI provides a reproducible method to obtain T1 values in the brain. Regional variation in T1 values is present in N(A)WM of volunteers and MS patients. Since T1 histogram parameters reflect changes in NAWM and correlate with conventional measures of disease burden in MS patients, T1 histogram analysis may provide a global measure of disease progression in MS. J. Magn. Reson. Imaging 2003;18:656–664. © 2003 Wiley‐Liss, Inc.
DTI‐based three‐dimensional tractography detects differences in the pyramidal tracts of infants and children with congenital hemiparesis
Authors: Glenn Orit A. , Henry Roland G. , Berman Jeffrey I. , Chang Patrick C. , Miller Steven P. , Vigneron Daniel B. , Barkovich A. James
Published: November 2003

Purpose

To test the hypothesis that there is greater asymmetry in diffusion properties between right and left pyramidal tracts in patients with congenital hemiparesis than in patients with normal motor function.

Materials and Methods

Four congenitally hemiparetic patients and four age‐matched controls underwent magnetic resonance diffusion tensor imaging (DTI)‐based three‐dimensional tractography of the pyramidal tracts. Relative anisotropy, individual eigenvalues, and directionally averaged apparent diffusion coefficient were measured and degree of asymmetry was calculated.

Results

Compared with age‐matched controls, congenitally hemiparetic patients had greater asymmetry in all measured diffusion properties. The asymmetry was characterized primarily by lower anisotropy, lower parallel diffusion, higher transverse diffusion, and slightly higher mean diffusivity in the pyramidal tract contralateral to the hemiparesis (i.e., affected pyramidal tract) compared with the unaffected pyramidal tract.

Conclusions

There appears to be greater diffusion asymmetry between the pyramidal tracts in congenitally hemiparetic patients compared to controls. These differences suggest that there are alterations in the microstructure of the pyramidal tract that controls the motor function of the hemiparetic side. Our results suggest that DTI‐based three‐dimensional tractography is potentially useful in the assessment of motor dysfunction in infants and children with congenital hemiparesis. J. Magn. Reson. Imaging 2003;18:641–648. © 2003 Wiley‐Liss, Inc.
Characteristic Interactions between Poly(hydroxybutyrate) Depolymerase and Poly[(R)‐3‐hydroxybutyrate] Film Studied by a Quartz Crystal Microbalance
Authors: Yamashita Koichi , Funato Takashi , Suzuki Yoichi , Teramachi Shinya , Doi Yoshiharu
Published: November 2003

Enzymatic degradation of poly[(R)‐3‐hydroxybutyrate] (P(3HB)) film by the poly(hydroxybutyrate) (PHB) depolymerase from Ralstonia picketti T1 was studied in 0.01 M phosphate buffer solution (pH 7.4) at 37 °C by using a quartz crystal microbalance (QCM) technique. Enzymatic degradation of P(3HB) film was quantitatively followed by QCM as a positive frequency shift. While, the amount of depolymerases adsorbed on the film could be evaluated as a negative frequency shift by using a mutant enzyme which had no hydrolytic activity in a catalytic site. The degradation rate increased with enzyme concentration to reach a maximum value at 1.0 μg · mL−1, and then the rate decreased at higher enzyme concentration. This enzyme concentration dependence could be quantitatively explained in terms of a change of coverage of the film surface by the adsorbed enzyme. When the wild‐type enzyme solution in a QCM cell was replaced with the mutant enzyme solution in the middle of the reaction, the degradation rate was reduced markedly, indicating that the wild‐type enzyme adsorbed on the P(3HB) surface is easily substituted by the mutant enzyme in the solution. On the other hand, replacement of the wild‐type enzyme solution with other proteins or buffer solutions did not affect the degradation rate at all, suggesting that the adsorbed enzyme was not desorbed from the film surface. Thus, the adsorbed PHB depolymerase is released from the P(3HB) surface only by interaction with the same depolymerase in solution.

Time courses of frequency changes (ΔF) or weight changes (Δw) observed during enzymatic degradation of P(3HB) film by PHB depolymerase from R. picketti T1 at 37 °C.

magnified image

Time courses of frequency changes (ΔF) or weight changes (Δw) observed during enzymatic degradation of P(3HB) film by PHB depolymerase from R. picketti T1 at 37 °C.
Chemoenzymatic Synthesis of a Multivalent Aminoglycoside
Authors: Miura Yoshiko , Ikeda Takayasu , Wada Natsuko , Kobayashi Kazukiyo
Published: November 2003

A polymeric aminoglycoside was prepared by a facile chemoenzymatic reaction. Boc‐protected aminoglycoside, amikacin, was chemoselectively esterified with divinyl sebacate at a hydroxyl group in the C6″ position by protease from Bacillus subtilis. The resulting 3,6′,3″,4‴‐tetra‐N‐Boc‐6″‐O‐vinyl sebacate was copolymerized with maltitol 6‐vinyl sebacate to yield a polymeric amikacin. The polymeric amikacin showed a modest inhibitory effect on in vitro protein synthesis, and a little antibiotic activity in minimum inhibitory concentration (MIC) assay in the presence of protease.

The synthesis of Boc‐protected amikacin ester by an enzyme‐catalyzed (protease) esterification.

magnified image

The synthesis of Boc‐protected amikacin ester by an enzyme‐catalyzed (protease) esterification.
Bergman and Bloch spaces of vector‐valued functions
Authors: Arregui José Luis , Blasco Oscar
Published: November 2003

We investigate Bergman and Bloch spaces of analytic vector‐valued functions in the unit disc. We show how the Bergman projection from the Bochner‐Lebesgue space Lp(𝔻, X) onto the Bergman space Bp(X) extends boundedly to the space of vector‐valued measures of bounded p‐variation Vp(X), using this fact to prove that the dual of Bp(X) is Bp(X*) for any complex Banach space X and 1 < p < ∞. As for p = 1 the dual is the Bloch space ℬ︁(X*). Furthermore we relate these spaces (via the Bergman kernel) with the classes of p‐summing and positive p‐summing operators, and we show in the same framework that Bp(X) is always complemented in 𝓁p(X). (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chaos for semigroups of unbounded operators
Authors: deLaubenfels R. , Emamirad H. , Grosse‐Erdmann K.‐G.
Published: November 2003

In this paper we generalize the notion of hypercyclic and chaotic semigroups to families of unbounded operators. We study this concept within the frameworks of C‐regularized semigroups and of regular distribution semigroups. We then apply our results to unbounded semigroups generated by differential operators with constant coefficients in weighted spaces and to the unbounded semigroup {(–Δ)t}t≥0, where . is the Laplacian operator. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boundary values of integral operators
Authors: Hefer Torsten
Published: November 2003

Consider a differential form u in the image of an integral operator K on a smooth domain D in a Riemannian manifold, i.e. u(y) = Kf(y) = ∫x∈D f(x) ∧ K(x, y) for y ∈ D. If the kernel K of the integral operator is sufficiently regular and defined also for y in the boundary bD of D, one may define two different kinds of boundary values of u on bD. Firstly, u may have boundary values in the sense of distributions, i.e. boundary values satisfying a Stokes' formula in a suitably weak sense. Secondly, one can simply restrict (pull back) y in the kernel K(x, y) to the boundary of D, then integrate with respect to x in the above formula. It is interesting to know under which hypotheses on f and K both types of boundary values agree, because the boundary values defined by restricting the kernel can often be estimated by direct methods, whereas the abstractly given distributional boundary values are less tractable but analytically interesting objects linked to u. We will give counter‐examples to show that even in quite regular situations the two notions do not necessarily agree. Then we study conditions implying equality. We also mention some interesting applications, e.g. generalizations of Stokes' formula and applications in the theory of integral representations in several complex variables. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On half‐line spectra for a class of non‐self‐adjoint Hill operators
Authors: Shin Kwang C.
Published: November 2003

In 1980, Gasymov showed that non‐self‐adjoint Hill operators with complex‐valued periodic potentials of the type $ V(x) = \sum ^{\infty} _{k=1} a_{k} e^{ikx} $, with $ \sum ^{\infty} _{k=1} \vert a_{k} \vert < \infty $, have spectra [0, ∞). In this note, we provide an alternative and elementary proof of this result. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
One‐Step Synthesis and Size Control of Dendrimer‐Protected Gold Nanoparticles: A Heat‐Treatment‐Based Strategy
Authors: Sun Xuping , Jiang Xiue , Dong Shaojun , Wang Erkang
Published: November 2003

Dendrimer‐protected gold nanoparticles have been facilely obtained by heating an aqueous solution containing third‐generation poly(propyleneimine) dendrimers and HAuCl4 without the additional step of introducing other reducing agents. Transmission electron microscopy (TEM) and UV‐vis data indicate the size, the nucleation, and growth kinetics of gold nanoparticles thus formed, which can be tuned by changing the initial molar ratio of dendrimer to gold.

The formation of dendrimer–gold nanoparticles by the heat treatment of an aqueous solution containing third‐generation poly(propyleneimine) dendrimers and HAuCl4.

magnified image

The formation of dendrimer–gold nanoparticles by the heat treatment of an aqueous solution containing third‐generation poly(propyleneimine) dendrimers and HAuCl4.
Abnormal sensorimotor integration is related to disease severity in Parkinson's disease: A TMS study
Authors: Tamburin Stefano , Fiaschi Antonio , Idone Domenico , Lochner Piergiorgio , Manganotti Paolo , Zanette Giampietro
Published: November 2003

Hyperexcitability of the motor system has been reported in Parkinson's disease (PD). We evaluate how cutaneous afferents modulate motor excitability in PD patients and whether abnormal modulation is correlated to parkinsonian symptoms. Digital stimulation causes abnormal enhancement of motor responses in patients. This effect may be one of the features of motor hyperexcitability in PD. Cutaneomotor hyperexcitability correlates with clinical scores, suggesting that abnormal processing of cutaneous inputs might contribute to the pathogenesis of parkinsonian symptoms. © 2003 Movement Disorder Society
Corticobasal degeneration as a cognitive disorder
Authors: Graham Naida L. , Bak Thomas H. , Hodges John R.
Published: November 2003

The presence of cognitive impairment in corticobasal degeneration (CBD) is now widely recognised. Our review of the literature reveals that, although the pattern and severity of neuropsychological impairments can be highly variable across patients, several general trends can be identified. The most characteristic impairments are limb apraxia (usually ideomotor), constructional and visuospatial difficulties, acalculia, frontal dysfunction, and nonfluent aphasia. The limb apraxia is associated with deficits in drawing, copying, and handwriting, but there is emerging evidence that the problems with handwriting are not due exclusively to the apraxia. The findings with respect to episodic memory are more variable, but when there is impairment in this area, it tends to be milder than that seen in Alzheimer's disease. Semantic memory functioning appears relatively preserved but has been poorly studied. Problems with speech are common, and may be due to dysarthria or buccofacial apraxia. Aphasia, although initially considered rare, is in fact a common accompaniment of CBD, may be the presenting feature, and is typically nonfluent in type. More systematic investigation of the clinical and neuropathological overlap between progressive nonfluent aphasia (generally considered to be a form of frontotemporal dementia) and CBD is needed.© 2003 Movement Disorder Society
Separate ipsilateral and contralateral corticospinal projections in congenital mirror movements: Neurophysiological evidence and significance for motor rehabilitation
Authors: Cincotta Massimo , Borgheresi Alessandra , Balzini Lara , Vannucchi Luca , Zeloni Gabriele , Ragazzoni Aldo , Benvenuti Francesco , Zaccara Gaetano , Arnetoli Graziano , Ziemann Ulf
Published: November 2003

The neurophysiological hallmark of congenital mirror movements (MM) are fast‐conducting corticospinal projections from the hand area of one primary motor cortex to both sides of the spinal cord. It is still unclear whether the abnormal ipsilateral projection originates through branching fibres from the normal contralateral projection or constitutes a separate ipsilateral projection. To clarify this question, we used focal paired‐pulse transcranial magnetic stimulation to test task‐related modulation of short‐interval intracortical inhibition (SICI) in the abductor pollicis brevis (APB) muscles of a 15‐year‐old girl (Patient 1) and a 40‐year‐old woman (Patient 2) with congenital MM. In both patients, during intended unilateral APB contraction, SICI decreased markedly in the “task” APB but remained unchanged in the “mirror” APB when compared to muscle rest. In contrast, spinal excitability as tested with H reflexes increased similarly in the task and mirror flexor carpi radialis muscles. This dissociation of task‐related SICI modulation strongly supports the existence of a separate ipsilateral fast‐conducting corticospinal projection. In Patient 1, we tested the functional significance of this separate ipsilateral projection during 7 months of motor rehabilitation training, which was designed to facilitate unilateral finger movements. A marked reduction of MM was observed after training, suggesting that unwanted mirror activity in the ipsilateral pathway can be suppressed by learning. © 2003 Movement Disorder Society
Prevalence of primary late‐onset focal dystonia in the Belgrade population
Authors: Pekmezović Tatjana , Ivanović Nataša , Svetel Marina , Nalić Dragana , Smiljković Tatjana , Raičević Ranko , Kostić Vladimir S.
Published: November 2003

The aim of this cross‐sectional study was to estimate the prevalence of different subtypes of idiopathic focal dystonia in the population of Belgrade (Serbia), Yugoslavia. On December 31, 2001, the crude prevalence of all studied types of dystonia (focal, segmental, and multifocal) in Belgrade was 13.6 per 100,000 population (11.8 per 100,000 for men and 15.2 per 100,000 for women). Type‐specific prevalence for focal dystonia was 11.2 per 100,000. The prevalence for cervical dystonia, blepharospasm, writer's cramp and laryngeal dystonia were 5.9 per 100,000, 1.9 per 100,000, 1.9 per 100,000, and 1.1 per 100,000, respectively. © 2003 Movement Disorder Society
Structural elucidation and total assignment of the 1H and 13C NMR spectra of new chalcone dimers
Authors: Bandeira Mary Anne M. , Matos F. J. de A. , Braz‐Filho R.
Published: November 2003

Conventional 1D NMR methods and 2D shift‐correlated NMR experiments (COSY, HMQC, HMBC) were used for the structural elucidation and 1H and 13C chemical shifts assignments of four new types of chalcone dimers isolated from Myracrodruon urundeuva. Copyright © 2003 John Wiley & Sons, Ltd.
Combined 1H, 13C and 11B NMR and mass spectral assignments of boronate complexes of D‐(+)‐glucose, D‐(+)‐mannose, methyl‐α‐D‐glucopyranoside, methyl‐β‐D‐galactopyranoside and methyl‐α‐D‐mannopyranoside
Authors: Smoum Reem , Rubinstein Abraham , Srebnik Morris
Published: November 2003

Complex formation between N‐butylboronic acid and D‐(+)‐glucose, D‐(+)‐mannose, methyl‐α‐D‐glucopyranoside, methyl‐β‐D‐galactopyranoside and methyl α‐D‐mannopyranoside under neutral conditions was investigated by 1H, 13C and 11B NMR spectroscopy and gas chromatography–mass spectrometry (GC–MS) D‐(+)‐Glucose and D‐(+)‐mannose formed complexes where the boronates are attached to the 1,2:4,6‐ and 2,3:5,6‐positions of the furanose forms, respectively. On the other hand, the boronic acid binds to the 4,6‐positions of the two methyl derivatives of glucose and galactose. Methyl α‐D‐mannopyranoside binds two boronates at the 2,3:4,6‐positions. 11B NMR was used to show the ring size of the complexed sugars and the boronate. GC–MS confirmed the assignments. Copyright © 2003 John Wiley & Sons, Ltd.
Gelsolin‐related familial amyloidosis, Finnish type, in a Portuguese family: Clinical and neurophysiological studies
Authors: Conceição Isabel , Sales‐Luis Maria Lurdes , De Carvalho Mamede , Evangelista Teresinha , Fernandes Rui , Paunio Tiina , Kangas Hannele , Coutinho Paula , Neves Carlos , Saraiva Maria João
Published: November 2003

We report a Portuguese family with familial amyloid polyneuropathy related to gelsolin. There were no known Finnish ancestors, but the same mutation as described in Finnish patients (G654A) was carried. Clinical and neurophysiological investigations were performed in four patients. Corneal lattice dystrophy affected all four patients; an axonal lesion of the facial nerve occurred in three patients; visual tract involvement was documented in one case; and corticospinal and posterior column dysfunction was present in one patient. Polarizing microscopy of skin and muscle samples demonstrated amyloid deposits in two patients; anti‐gelsolin immunohistochemistry was positive for amyloidogenic gelsolin. The Finnish mutation of gelsolin protein (G654A) was detected in five family members. The utility of neurophysiological testing in the evaluation and follow‐up of this type of amyloidosis is discussed. Muscle Nerve 28: 715–721, 2003
Characterisation of castor oil by on‐line and off‐line non‐aqueous reverse‐phase high‐performance liquid chromatography–mass spectrometry (APCI and UV/MALDI)
Authors: Stübiger Gerald , Pittenauer Ernst , Allmaier Günter
Published: November 2003

A non‐aqueous reverse‐phase HPLC method, based on two columns in series, has been used to separate the major triacylglycerols (TAGs) from commercial castor oil and to perform either on‐line negative ion atmospheric pressure chemical ionisation (APCI), or off‐line positive ion matrix‐assisted laser desorption ionisation (MALDI)/MS. The resulting Mass Spectra showed chloride‐attached TAG molecules [M + Cl]− in the case of negative‐ion APCI, and sodium‐attached TAG molecules [M + Na]+ in the case of positive‐ion MALDI. For MALDI time‐of‐ﬂight (TOF)/MS, a liquid binary matrix system consisting of sodium ferrocyanide and glycerol was applied, resulting in excellent TAG sensitivity, which was necessary for the determination of trace amounts of TAGs in castor oil. Both techniques allowed unambiguous molecular mass determination of the intact TAG molecules with no thermal degradation. Furthermore, seamless post source decay (PSD) fragment ion analysis by means of a curved ﬁeld reﬂector TOF mass spectrometer allowed the determination of the fatty acid composition of each individual TAG. Castor oil contained eight different TAGs which were successfully determined by both APCI and MALDI techniques. In each TAG, at least two units of 12‐hydroxy‐9‐octadecenoic acid (ricinoleic acid) were present. The following fatty acids were determined by seamless PSD fragment ion analysis and APCI/MALDI molecular mass determination as TAG substructures: ricinoleic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, dihydroxy stearic acid and eicosenoic acid. Triricinolein was the dominating TAG. Copyright © 2003 John Wiley & Sons, Ltd.