bluuebunny/crossref_metadata_2025 huggingface dataset:
Modification of chitin properties for enzymatic deacetylation
Authors: Beaney Paul D. , Gan Quan , Magee Thomas R. A. , Healy Michael , Lizardi‐Mendoza Jaime
Published: January 2007

Chitins produced via a conventional chemical route as well as from a new biological process were modified to increase the efficiency of enzymatic deacetylation reactions for the production of novel biological chitosan. These modified chitins were reacted for 24 h with extracellular fungal enzymes from Colletotrichum lindemuthianum. The chemical and physical properties of the various substrates were analysed and their properties related to the effectiveness in the deacetylation reaction. Modifications of the chitins affected the degree of deacetylation with varied effects. Without further modification to reduce crystallinity and to open up the solid substrate structure, the chitins were found to be poor substrates for the heterogeneous solid‐liquid enzymatic catalysis. It was found that the solvent and drying method used in modifying the chitins had significant impact on the final efficiency of the enzymatic deacetylation reaction. The most successful modifications through freeze drying of a colloidal chitin suspension increased the degree of enzymatic deacetylation by 20 fold. These processes reduce the crystallinity of the chitin making it easier for the enzymes to access their internal structure. X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and BET isotherm analysis are employed to characterise the modified chitins to ascertain the degree of crystallinity, porous structure, surface area, and morphology. Copyright © 2007 Society of Chemical Industry
Drosophila melanogaster and Eucypris virens giant spermatozoa as visualized by cell inclusion in microgels
Authors: López‐Fernández C. , Baltanás A. , De La Torre J. , Gosálvez J.
Published: January 2007

A new technique, based on live Sperm Inclusion in Microgels (SIM), allows quick and easy analysis of giant spermatozoa under bright field or fluorescence microscopy. The technique has been assayed on Drosophila melanogaster (Diptera) and Eucypris virens (Ostracoda) spermatozoa and based on the inclusion of freshly obtained male gametes in low melting agarose microgels at 37°C to prevent cell damage. Gametes spread onto pretreated slides are dehydrated and directly observed under phase contrast microscopy or stained with specific fluorochromes for DNA or proteins. Results show that the morphology of whole sperm is highly preserved allowing identification of sperm characteristics difficult to visualize after using standard fixation procedures. In Drosophila melanogaster, SIM allows the simultaneous visualization of the complete flagellum plus a clear delineation of the DNA. It also allows observation of morphological changes in the perforatorium as sperm elongation takes place. In E. virens, SIM slides visualized under phase contrast and fluorescence microscopy show three main morphological regions on the entire spermatozoa. Spermatozoa of this species are auto‐fluorescent under wavelength excitation from 387 to 562 nm. In spite of this, clear localization of the DNA molecule at the posterior 1/3 part of the whole spermatozoa can also be achieved after single DAPI staining or in combination with Mercuri‐diBrom‐Fluorescein, a fluorochrome for protein targeting. J. Exp. Zool. 307A, 2007. © 2007 Wiley‐Liss, Inc.
Sequence, expression and evolutionary relationships of carbamoyl phosphate synthetase I in the toad Xenopus laevis
Authors: Lindley Timothy E. , Laberge Tammy , Hall Aaron , Hewett‐Emmett David , Walsh Patrick J. , Anderson Paul M.
Published: January 2007

The sequence of carbamoyl phosphate synthetase I (CPSase I) cDNA and expression of the enzyme in liver of the toad Xenopus laevis are reported. CPSase I mRNA increases 6‐fold when toads are exposed to high salinity for extended periods of time. The deduced 1,494‐amino acid sequence of the CPSase I is homologous to other CPSases and reveals a domain structure and conserved amino acids common to other CPSases. A serine residue (S287) is present where there is a cysteine residue required for glutamine‐dependent activity in CPSase Types III and II (Type I CPSases utilize only ammonia as nitrogen‐donating substrate). A sequence of DNA 964 bases upstream from the ATG start codon for the CPSase I gene is also reported. Phylogenetic analysis for 30 CPSase isoforms, including X. laevis CPSase I, across a wide spectrum of phyla is reported and discussed. The results are consistent with the views that eukaryotic CPSase II as a multifunctional complex evolved from prokaryotic CPSase II and that CPSase I in terrestrial vertebrates and CPSase III in fishes arose from eukaryotic CPSase II by independent events after the divergence of plants in eukaryotic evolution. J. Exp. Zool. 307A, 2007. © 2007 Wiley‐Liss, Inc.
A critical examination of the sodium dodecyl sulfate (SDS) sedimentation test for wheat meals
Authors: Morris Craig F , Paszczynska Bozena , Bettge Arthur D , King Garrison E
Published: January 2007

Sedimentation tests have long been used to characterise wheat flours and meals with the aim of predicting processing and end‐product qualities. However, the use of the sodium dodecyl sulfate (SDS) sedimentation test for durum wheat (AACC International Approved Method 56–70) has not been characterised for hexaploid wheat varieties with a diverse range of protein quality and quantity. This paper reports the variation associated with important method parameters: sample weight, SDS concentration, technician, grinder and screen aperture (particle size). Sedimentation volumes were recorded every 5 min for 30 min and expressed as specific volume, i.e. sediment volume in mL g−1 meal. Ten diverse hexaploid wheat samples of markedly different protein quality and quantity were examined. The SDS sedimentation assay was shown to be highly robust and reproducible, with ANOVA (analysis of variance) model R2 values greater than 0.98 (individual time points). The procedure delineated soft and hard hexaploid wheat samples based on a combination of protein quantity and quality. Sample weight (if corrected to unit weight basis), recording time of at least 10 min, SDS stock concentration of at least 10 g L−1 (final), grinder type and screen aperture were minor sources of variation in SDS sedimentation volume relative to the effects due to differences among wheat samples. Interactions among ANOVA model terms were of relatively minor importance. Published in 2007 by This article is a US Government work and is in the public domain in the USA.
The quasienergy spectrum of argon from 400 to 800 nm
Authors: Mede E , Potvliege R M
Published: January 2007

The Floquet quasienergy spectrum of argon atoms exposed to a strong laser field is presented for incident wavelengths of 400, 600, and 800 nm and electron excursion amplitudes up to 30 a.u. The calculation is performed by diagonalizing the Floquet Hamiltonian on a discrete basis of Sturmian functions, the atom being described by a one-electron model potential. How the quasienergies of the dressed bound states change as functions of both the wavelength and the intensity of the incident field is studied. The spectrum of the dressed excited states varies slowly with these two parameters, apart for a number of changes between direct and avoided crossings and for less frequent, more profound reorganizations. The spectrum converges at high intensity towards that predicted by the high-frequency Floquet theory.
Flow measurements: Can several “Wrongs” make a “Right”?
Authors: Caffarel Jennifer , Robson Wendy , Pickard Robert , Griffiths Clive , Drinnan Michael
Published: January 2007

Aims

Although measurement of maximum flow rate (Qmax) is a standard and straightforward test, it is often difficult to obtain reliable readings. We obtained multiple measurements using a simple home uroflow device which categorizes Qmax into ranges. We hypothesize that the average of a series of relatively coarse measurements of Qmax would be more repeatable and therefore more representative of an individual's voiding function than a single, albeit more precise measurement.

Methods

We studied 22 male volunteers with a wide range of Qmax. They were asked to record flow category (<10 ml/sec; 10–15 ml/sec; 15–20 ml/sec; >20 ml/sec) and voided volume twice daily for 12 days using the home flow device. In addition, a clinic‐based flow recording using a spinning‐disc uroflowmeter was obtained at both the start and the end of the 12‐day period.

Results

Good agreement between mean home flow and mean clinic flow was seen with mean (SD) difference of 1.3 (5) ml/sec. The mean for consecutive halves of an individual's home flow data showed excellent agreement (−0.2 (1.3) ml/sec). The two clinic readings showed poorer agreement (2.3 (6.8) ml/sec) than the home readings, and poorer agreement even than between clinic and home flows.

Conclusions

Although simple in design, the home flowmeter actually shows greater accuracy than might be expected when used repeatedly to study the flow rates of men. Simple flow devices such as this could be used in conjunction with voiding diaries to give a more representative picture of patients' day‐to‐day voiding function. Neurourol. Urodynam. 26:474–480, 2007. © 2007 Wiley‐Liss, Inc.
Identification of abacavir hypersensitivity reaction in health care claims data
Authors: Nordstrom Beth L. , Norman Heather S. , Dube Timothy J. , Wilcox Marsha A. , Walker Alexander M.
Published: January 2007

Purpose

Abacavir is associated with an infrequent but potentially serious hypersensitivity reaction (HSR) that can include a wide range of signs and symptoms. Identification of this reaction through medical insurance claims could provide a simple and efficient means of monitoring the incidence of abacavir hypersensitivity in large populations of patients.

Methods

Using data from a safety study of 948 abacavir users with 22 hypersensitivity events identified from claims and validated through medical record review, we used a recursive partitioning analysis to construct an algorithm to differentiate between patients with and without validated adverse events. Bootstrap resampling techniques provided validation for the analysis.

Results

The analysis produced a classification tree with three decision nodes that comprised the best indicators of HSRs. The predictors included any one of several specific symptoms commonly found with this reaction, a claims diagnosis of adverse effect of drug, anaphylactic shock or unspecified allergy, and a discontinuation in abacavir prior to completing a 90‐day course of therapy. The algorithm demonstrated 95% sensitivity and 90% specificity when tested using a bootstrap resampling approach with the current data.

Conclusions

A sensitive and specific algorithm for identifying abacavir hypersensitivity from claims was created. This algorithm would permit efficient identification of charts for medical review. Further testing of the algorithm with additional medical claims data for abacavir users will be required to ascertain its validity across databases. Copyright © 2007 John Wiley & Sons, Ltd.
Short‐term reactogenicity and gender effect of anthrax vaccine: analysis of a 1967–1972 study and review of the 1955–2005 medical literature
Authors: McNeil Michael M. , Chiang I‐Shan , Wheeling John T. , Zhang Yujia
Published: January 2007

Purpose

In the 1960s, the Centers for Disease Control and Prevention (CDC) held the investigational new drug (IND) application for the anthrax vaccine and collected short‐term safety data from approximately 16 000 doses administered to almost 7000 individuals. While some recent anthrax vaccine safety studies have suggested that women experience more injection site reactions (ISRs), to our knowledge the IND safety data were not previously examined for a gender‐specific difference.

Methods

We identified and analyzed a subset of the IND study data representing a total of 1749 persons who received 3592 doses from 1967 to 1972. Original data collection forms were located and information extracted, including: vaccine recipient's name, age at vaccination, gender, dose number, date of vaccination, lot number, grading of ISR, presence and type of systemic reactions. Overall and gender‐specific rates for adverse reactions to anthrax vaccine were calculated and we performed a multivariable analysis.

Results

We found an ISR was associated with 28% of anthrax vaccine doses; however, 87% of these were considered mild. Systemic reactions were uncommon (<1%) and most (70%) accompanied an ISR. Our dose‐specific analysis by gender found women had at least twice the risk of having a vaccine reaction compared to men. Our age‐adjusted relative risk for ISR in women compared to men was 2.78 (95%CI: 2.29, 3.38).

Conclusions

Our results for both overall and gender‐specific reactogenicity are consistent with other anthrax safety studies. To date, possible implications of these gender differences observed for anthrax and other vaccines are unknown and deserve further study. Copyright © 2007 John Wiley & Sons, Ltd.
Application of lag‐time into exposure definitions to control for protopathic bias
Authors: Tamim H. , Monfared A. A. Tahami , LeLorier J.
Published: January 2007

Purpose

To control for protopathic bias, some studies have incorporated the concept of lag‐time into their exposure definition (time period before the index date that was not considered in assessing exposure). The objective of this study was to introduce a procedure to identify the best lag‐time to be applied in studies where control for protopathic bias is required.

Methods

We used data from a case‐control study carried out to assess the association between exposure to proton pump inhibitors (PPIs) and risk of gastric cancer, using RAMQ databases. Exposure was defined as the number of defined daily doses of PPIs dispensed during the 5‐year period prior to the index date (divided into four quartiles). Thirty‐one different lag‐times were applied (0–30 months) based on 1‐month intervals. Logistic regression was used to estimate the matched odds ratio (OR) for each lag‐time. The change point in the ln(ORs) was identified by applying a two‐compartmental model and a segmented regression model.

Results

A trend of decreasing ORs was found with the application of an increasing lag‐time. As an illustration, the ORs for the 1st quartile of defined daily doses, when applying the 31 different lag‐times, ranged between 3.52 when applying a 0 lag‐time and 0.97 when applying a 30 months lag‐time. Applying the two methods for the different lag‐times showed that the ORs stabilized at around 6 months.

Conclusion

For the purpose of controlling for protopathic bias in pharmacoepidemiological studies, we have provided a method to assess the most appropriate lag‐time that should be applied for the assessment of drug exposure. Copyright © 2007 John Wiley & Sons, Ltd.
Novel in situ coordination copper sulfate/ acrylonitrile–butadiene rubber composite
Authors: Yuan Xiaofang , Shen Fei , Wu Guozhang , Wu Chifei
Published: January 2007

A novel rubber composite of acrylonitrile–butadiene rubber (NBR) filled with anhydrous copper sulfate (CuSO4) particles was investigated. Dynamic mechanical analysis, differential scanning calorimetry, X‐ray photoelectron spectroscopy, tensile testing, and an equilibrium swelling method were used for the characterization of this novel CuSO4/NBR composite. The results indicated that the composite had wonderful mechanical properties, which profited from the in situ coordination crosslinking interactions between the nitrile groups (CN) of NBR and solid CuSO4 particles. Scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and transmission electron microscopy results showed that CuSO4 particles played two roles, acting as both crosslink agents and reinforcing fillers in the matrix. The double actions of CuSO4 gave the CuSO4/NBR composites their excellent mechanical properties. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 571–576, 2007
Pressure dependence of superconducting transition temperature of MgB2 up to 8 GPa
Authors: Ma R. , Liu M. , Wang Y. G. , Yang Y. H.
Published: January 2007

The pressure dependence of electronic structure, phonon frequencies, electron–phonon coupling constant, and the superconducting transition temperature Tc in MgB2 are calculated via zone‐center frozen phonon modes calculations using the FP‐LAPW method. The calculations are performed from pressure dependent lattice parameters measured experimentally up to 8 GPa. Under quasi‐hydrostatic pressure, Tc is found to decrease with an approximately quadratic dependence, deviating significantly from the linearity. It is shown that the pressure‐induced anisotropic change of lattice parameters, the increasing E2g phonon frequency, and nonlinear electron–phonon coupling are three key factors of producing nonlinear Tc(P) observed in MgB2. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Compositional dependence of optical and vibrational properties of strontium barium niobate (SrxBa1–xNb2O6)
Authors: David C. , Tunyagi A. , Betzler K. , Wöhlecke M.
Published: January 2007

The index of refraction, the optical band edge and the Raman scattering of strontium barium niobate, Srx Ba1–x Nb2O6 with 0.38 < x < 0.77 have been studied. The ordinary refractive index does not depend on x, while the extra‐ordinary one increases with increasing x. The band edge is almost unaffected by the Ba‐ or Sr‐content and shows a weak band bowing. Both the index of refraction and the band edge may be used for an optical determination of the composition of the crystal. Raman spectra show the typical behavior of tungsten bronze type crystals with broad bands and complicated spectral shapes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of anisotropic exchange on the micromagnetic domain structures
Authors: Schaadt D. M. , Engel‐Herbert R. , Hesjedal T.
Published: January 2007

We have investigated the influence of anisotropic exchange on the micromagnetic domain structure. Three‐dimensional simulations based on the Landau–Lifshitz–Gilbert equation were performed incorporating a generalized tensor representation of the exchange following a phenomenological approach. In comparison to isotropic exchange, which is usually used in micromagnetic simulations, anisotropic exchange significantly affected the equilibrium distribution of the magnetization. The formation of slanted domain walls aligning in the direction of stiffest exchange and the deformation of edge domains were the most prominent consequences. In general, we found that anisotropic exchange may have profound effects on magnetic nanostructures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Increase in water resistance of paperboard by coating with poly(lactide)
Authors: Rhim Jong‐Whan , Lee Jun‐Ho , Hong Seok‐In
Published: January 2007

Poly(lactide) (PLA)‐coated paperboards (PB) were prepared, and the effect of coating for improving water resistance of paperboard used for corrugated box liners was tested. Surface of paperboards became smoother through PLA coating, and their thickness and weight of coating increased depending on the concentration of the coating solution. Tensile strength of paperboard decreased, while elongation at break (E) increased after PLA coating. All water barrier properties tested, such as water vapour permeability (WVP), water absorptiveness (WA) and contact angle (CA) of water drop, indicated that water resistance of paperboard was improved through surface coating with PLA. WVP decreased from 4.8 to 25.5 times, and WA decreased from 11.9 to 17.9 times depending on the PLA concentration. The increase in water resistance of PLA‐coated paperboards was due to the hydrophobicity of PLA, which was proven through CA measurement. CA determined by both static and dynamic methods demonstrated the increase in initial CA of PLA‐coated paperboards, indicating an increased hydrophobicity of surface. All test results indicated that the optimum concentration of coating solution for improving water resistance of paperboard was 3 w/v % of PLA soulution. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of formalin and ethanol preservation on otolith δ18O stable isotope signatures
Authors: Storm‐Suke A. , Dempson J. B. , Caron F. , Power M.
Published: January 2007

The use of preserved otoliths for stable isotope analysis assumes handling and preservation procedures do not alter the isotopic composition of the otolith. Otoliths from wild and hatchery‐reared salmonids (brook charr, Salvelinus fontinalis, and Atlantic salmon, Salmo salar) were used to test for possible δ18O preservation effects in ethanol and formalin preservation experiments at varying temperatures. Analysis of variance (ANOVA) demonstrated a significant interaction effect between species and preservative during preservation. Possible causes for the observed effect are discussed in relation to species‐specific differences in otolith chemistry related to growth and environment including: (1) chemical mechanisms of dissolution‐recrystallisation involving the precipitation of secondary minerals within and at the otolith surface; (2) adsorption of ions at available binding sites on the otolith surface; and (3) isotopic exchange during otolith surface dissolution and/or reprecipitation processes. Differential occurrence of vaterite and aragonite in otoliths is believed to account for some of the observed effects as a result of otolith density differences. Isotopic exchange is also argued to cause much of the observed variation in species‐specific preservation effects. Biologically, study findings imply that preserved otoliths should not be used for baseline paleoclimatic or individual fish thermal reconstructions, or the development of δ18O‐fractionation equations, without the prior use of pilot studies to determine preservation effects. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of 3,5‐dichloroaniline as a biomarker of vinclozolin and iprodione in human urine using liquid chromatography/triple quadrupole mass spectrometry
Authors: Lindh Christian H. , Littorin Margareta , Amilon Åsa , Jönsson Bo A. G.
Published: January 2007

The fungicides vinclozolin and iprodione are widely used in agriculture. These pesticides are dicarboximide fungicides containing the common moiety 3,5‐dichloroaniline (3,5‐DCA). It has been suggested that low‐level exposures to such compounds may be associated with adverse health effects such as endocrine disruption. In this study a method using liquid chromatography/triple quadrupole mass spectrometry (LC/MS/MS) was developed for the analysis of 3,5‐DCA as a biomarker of exposure to these fungicides in human urine. The urine samples were treated by basic hydrolysis to degrade the fungicides, their metabolites and conjugates to 3,5‐DCA. The 3,5‐DCA was then extracted using toluene and derivatized using pentafluoropropionic anhydride (PFPA). Analysis of the derivative was carried out using selected reaction monitoring (SRM) in the negative ion mode. Quantification of the derivative was performed using [13C6]‐labeled 3,4‐DCA as an internal standard with good precision and linearity in the range 0.1–200 ng/mL urine. The limit of detection was determined to be 0.1 ng/mL. The metabolites in urine were found to be stable during storage at −20°C. To validate 3,5‐DCA as a biomarker the method was applied in a human experimental exposure to iprodione and vinclozolin. Two healthy volunteers received 200 µg single oral doses of each pesticide followed by urine sampling during 72–120 h post‐exposure. Between 78–107% of the dose was recovered as 3,5‐DCA in the urine after exposure. Copyright © 2007 John Wiley & Sons, Ltd.
Development of a multiplex non‐radioactive receptor assay: the benzodiazepine receptor, the serotonin transporter and the β‐adrenergic receptor
Authors: de Jong Lutea A. A. , Jeronimus‐Stratingh C. Margot , Cremers Thomas I. F. H.
Published: January 2007

Binding assays still form a fundamental part of modern drug development. Receptor binding assays are mostly based on radioactivity because of their speed, ease of use and reproducibility. Disadvantages, such as health hazards and production of radioactive waste, have prompted the development of non‐radioactive receptor binding assays. This application therefore focuses on measuring receptor‐ligand interactions using mass spectrometry. Moreover, the novelty of this approach originates in determining multiple analytes in a single assay (multiplexing). The proof of principle of a non‐radioactive multiplex receptor assay is demonstrated using a pool of receptors from rat cortical tissue with flunitrazepam, MADAM and pindolol in one vial with or without their respective displacers. Flunitrazepam, MADAM and pindolol bound specifically at 73%, 30% and 40% to their respective receptors. This corresponds to specific binding sites of 0.61 pmol/mg protein, 0.07 pmol/mg protein and 0.06 pmol/mg protein, respectively. We propose to measure the bound fraction instead of the free fraction in order to reach a significant difference in measured signals (total binding versus non‐specific binding). The bound fraction can be obtained after dissociating the ligand from the receptor‐ligand complex using 50% methanol in water. The current setup of the assay calls for further improvement with respect to the measurement of binding constants for a multitude of receptors in one assay with sufficient accuracy and precision. Copyright © 2007 John Wiley & Sons, Ltd.
Characterisation of nicotine and related compounds using electrospray ionisation with ion trap mass spectrometry and with quadrupole time‐of‐flight mass spectrometry and their detection by liquid chromatography/electrospray ionisation mass spectrometry
Authors: Smyth Thomas J. , Ramachandran V. N. , McGuigan Alex , Hopps Jason , Smyth W. Franklin
Published: January 2007

Electrospray ionisation ion trap mass spectrometry (ESI‐MSn) has been used to study the fragmentation patterns of nicotine and nine of its related compounds. From this study certain characteristic fragmentations are apparent with generally the pyrrolidine or piperidine ring being subject to chemical modifications. The structures of the product ions proposed for the ESI‐MSn study have been supported by results from electrospray ionisation quadrupole time‐of‐flight mass spectrometry (ESI‐QTOF‐MS). Compounds with pyrrolidine and piperidine rings that possess an unsubstituted N atom have been shown to lose NH3 at the MS2 stage. Those compounds with N‐methyl groups lose CH3NH2 at the MS2 stage. The loss of NH3 or CH3NH2 leaves the corresponding rings opened and this is followed by ring closure at the pyridine‐2 carbon atom. Mono‐N‐oxides fragment in a similar way but the di‐N‐oxide can also fragment by cleavage of the bond between the pyridine and pyrrolidine rings. Cotinine also can undergo cleavage of this bond between the rings.

This data therefore provides useful information on how substituents and the nature of the non‐pyridine ring can affect the fragmentation patterns of nicotine and its related compounds. This information can be used in the characterisation of these compounds by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) which results in the separation of nicotine and its related compounds with limits of detection (LODs) ranging from 15 to 105 ng/mL. The use of LC/ESI‐MS to study nicotine‐containing samples resulted in the simultaneous and unambiguous identification of seven of the compounds discussed in this paper: cotinine identified at retention time 12.5 min (with its [M+H]+ ion at m/z 177), nornicotine 16.0 min (m/z 149), anatabine 18.0 min (m/z 161), myosmine 18.5 min (m/z 147), anabasine 20.4 min (m/z 163), nicotine 22.2 min (m/z 163), and nicotyrine 31.4 min (m/z 159). For quality control of nicotine replacement therapy products, these nicotine impurities can be readily identified and determined at levels up to 0.3% for single impurities and up to 1.0% for total impurities. Copyright © 2006 John Wiley & Sons, Ltd.
Bayesian modelling of the dynamics of hepatotoxicity
Authors: Li Q. , Shen X. , Pearl D. K.
Published: January 2007

Hepatotoxicity (liver damage) is a common problem in drug treatment trials but is observed only indirectly through biomarkers measured in the blood. This creates the need to infer an individual's unobserved liver function dynamically using blood tests and other patient baseline characteristics. Major statistical challenges include high dimensionality, irregular time observation points over patients, presence of missing observations, and noise involved in measurement and biological processes. This article introduces a class of multivariate Bayesian dynamic stochastic models for detecting and forecasting changes in an individual's liver function in two situations: without and with drug. These models separate measurement error from variation inherent in a biological process, and describe the underlying process of liver detoxification, whereby, drug affects liver function which in turn induces changes in observed analytes. We apply the Bayesian methodology to make an inference. A clinical toxicity study is examined, together with simulated data. The results suggest that changes in observed analytes can be captured by the proposed models. Copyright © 2007 John Wiley & Sons, Ltd.
Nanostructured Polymer Brushes
Authors: Schmelmer Ursula , Paul Anne , Küller Alexander , Steenackers Marin , Ulman Abraham , Grunze Michael , Gölzhäuser Armin , Jordan Rainer
Published: January 2007

Nanopatterned polymer brushes with sub‐50‐nm resolution were prepared by a combination of electron‐beam chemical lithography (EBCL) of self‐assembled monolayers (SAMs) and surface‐initiated photopolymerization (SIPP). As a further development of our previous work, selective EBCL was performed with a highly focused electron beam and not via a mask, to region‐selectively convert a SAM of 4′‐nitro‐1,1′‐biphenyl‐4‐thiol to defined areas of crosslinked 4′‐amino‐1,1′‐biphenyl‐4‐thiol. These “written” structures were then used to prepare surface‐bonded, asymmetric, azo initiator sites of 4′‐azomethylmalonodinitrile‐1,1′‐biphenyl‐4‐thiol. In the presence of bulk styrene, SIPP amplified the primary structures of line widths from 500 to 10 nm to polystyrene structures of line widths 530 nm down to approximately 45 nm at a brush height of 10 or 7 nm, respectively, as measured by scanning electron microscopy and atomic force microscopy (AFM). The relative position of individual structures was within a tolerance of a few nanometers, as verified by AFM. At line‐to‐line spacings down to 50–70 nm, individual polymer brush structures are still observable. Below this threshold, neighboring structures merge due to chain overlap.
Sonographic assessment of normal fetal palate using three‐dimensional imaging: a new technique
Authors: Faure J. M. , Captier G. , Bäumler M. , Boulot P.
Published: January 2007

Objectives

The aim of this study was to describe a novel three‐dimensional (3D) ultrasound rendering technique to examine the normal fetal posterior palate and to assess its correspondence with the real fetal anatomy.

Methods

A prospective longitudinal study was conducted from January to October 2005 and included 100 fetuses in a low‐risk population. Fetal ultrasound examinations were performed at 17, 22, 27 and 32 weeks' gestation to determine the normal 3D ultrasound view of the fetal palate at different gestational ages. The ultrasound scans were performed using the strict anterior axial plane of the starting reconstruction volume and the underside 3D view of the fetal palate. The 3D view of the fetal palate was compared with the normal anatomical view of the fetal palate obtained by surgical fetopathological examination of fetuses at the same gestational ages. The sonographic visualization rates of seven defined anatomical landmarks of the fetal palate were computed for each gestational age. The visualization rates across gestational ages were compared by use of the Cochrane Q test. The reliability of detection of each anatomical landmark across gestational ages was determined by Cronbach's Alpha.

Results

In all cases a 3D ultrasound view of the fetal maxilla and secondary palate was obtained at each period of gestation and corresponded well to the fetal anatomical specimens. The seven defined anatomical landmarks of the fetal palate were identified in 42–100% of cases. The visualization rates across gestational ages were significantly different in five of these anatomical landmarks. These differences can be explained by different developmental processes of these anatomical structures. The overall reliability of visualization across the gestational ages for the anatomical landmarks was medium to very high (0.73–0.96), except for the landmark interpalatal suture which was low (0.48).

Conclusions

This technique of anterior axial 3D view reconstruction of the fetal palate seen by an underside view can provide unique diagnostic information on the integrity of the secondary palate. This innovative, simple and rapid technique may become the reference technique in ultrasound investigation of the fetal palate, and should be of value in diagnosing isolated secondary cleft palate or palatal involvement when cleft lip and alveolus are diagnosed. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Prenatal diagnosis of intestinal pseudo‐obstruction
Authors: Shen O. , Schimmel M. S. , Eitan R. , Granovsky‐Grisaru S. , Rabinowitz R. R.
Published: January 2007

The appearance of polyhydramnios and dilated bowel loops on prenatal sonographic examination usually implies mechanical obstruction. The prognosis is variable, depending on the etiology. Congenital pseudo‐obstruction, a potentially lethal disease, comprises a group of disorders characterized by intestinal obstruction in the absence of an anatomic lesion. This report focuses on the prenatal diagnosis of intestinal pseudo‐obstruction, and two cases of transient congenital intestinal pseudo‐obstruction in one family are described. In both, the prenatal sonographic presentation was of small bowel obstruction. In one case there was postnatal suspicion of neurogenic bladder, and in the other there was unilateral hydronephrosis. The sonographic appearance of intestinal pseudo‐obstruction is similar to that of mechanical obstruction. The clues to the prenatal diagnosis of pseudo‐obstruction include associated urinary tract abnormalities and a family history of pseudo‐obstruction. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
First‐trimester treatment of fetal anemia secondary to parvovirus B19 infection
Authors: Kempe A. , Rösing B. , Berg C. , Kamil D. , Heep A. , Gembruch U. , Geipel A.
Published: January 2007

Here we report two cases of first‐trimester parvovirus B19 (PV‐B19) infection that were successfully treated by intrauterine blood transfusion into the umbilical vein. At 13 weeks' gestation both fetuses presented with increased nuchal translucency (NT) and cardiomegaly. In both cases pulsed Doppler ultrasound examination of the fetal middle cerebral artery (MCA) revealed increased peak systolic velocity (PSV), which led to a suspicion of fetal anemia. Maternal PV infection was confirmed by a positive polymerase chain reaction result. Each fetus received a 3‐mL intravenous transfusion of packed red blood cells into the umbilical vein, using a 25‐G spinal needle. Follow‐up ultrasound and Doppler examination demonstrated fetal well‐being, decline of the MCA‐PSV and resolution of the NT. Case 1 was readmitted at 25 weeks' gestation with severe hydrops fetalis, and both mother and fetus still tested positive for PV‐B19 DNA. Three more intrauterine blood transfusions were performed and the fetal hydrops resolved. In Case 2 no additional transfusions were needed. Both babies had a good neonatal outcome and uneventful follow‐up. Our findings demonstrate that the MCA‐PSV is helpful in establishing the diagnosis of first‐trimester fetal anemia. Intravasal transfusion can be attempted as early as the first trimester. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Path tortuosity of Eurasian badgers (Meles meles) in a heterogeneous Mediterranean landscape
Authors: Loureiro Filipa , Rosalino Luís Miguel , Macdonald David W. , Santos‐Reis Margarida
Published: January 2007

Movement is the process by which individual organisms are displaced over time to eat, reproduce and defend resources. Fractal analysis is a technique used to study animal movement that measures spatial complexity of path tortuosity; here, we apply it to characterize the movement patterns of the Eurasian badger (Meles meles) in a Mediterranean landscape. We calculated path tortuosity overall and seasonally, and for individuals of different sexes and social groups. The influence of variables related to badgers’ resources (food, shelter, water), human infra‐structures and weather conditions were analysed with respect to the tortuosity of each badger's path. A total of 55 search paths from six badgers were considered for this study. Although badgers generally displayed convoluted movement, there were two exceptions: (a) males overall and (b) all badgers in summer; for both, movements had a lower fractal value, i.e. were less tortuous. The convoluted movement pattern generally observed is probably adapted to the clumped distribution of food in the study area. Nevertheless, our results suggest that the use of dens and latrines were the principal determinants of tortuosity of badgers’ paths while foraging.
Intramyocardial injection of vascular endothelial growth factor gene improves cardiac performance and inhibits cardiomyocyte apoptosis
Authors: Ruixing Yin , Dezhai Yang , Hai Wu , Kai Huang , Xianghong Wu , Yuming Chen
Published: January 2007

Background:

Previous studies suggest that vascular endothelial growth factor (VEGF) is a regulator of naturally occurring angiogenesis. However, whether VEGF plays a role in cardiomyocyte apoptosis is not known.

Aim:

To investigate the effects of intramyocardial injection of VEGF165 cDNA on cardiac performance and cardiomyocyte apoptosis in a rat model of acute myocardial infarction.

Methods:

Forty male Sprague–Dawley rats underwent left coronary artery ligation and were randomised to receive VEGF165 cDNA (treated group) or pcDNA3.1 (control), injected directly into the border zone of the ischaemic myocardium. Twenty rats underwent thoracotomy and injection of pcDNA3.1, without coronary ligation (sham group). Haemodynamic and apoptotic parameters were measured two weeks after injection.

Results:

Three sham, eight control, and five treated animals died. Haemodynamic parameters and microvessel counts in the treated group were significantly better than in the control (P<0.05 to 0.01). Apoptotic index in the treated group was less than in the control (P<0.01). Caspase‐3 activation and mitochondrial cytochrome c release in the treated group were also lower than in the control (P<0.01). VEGF165 cDNA treatment significantly inhibited p53, Fas, Bax, and increased VEGF and Bcl‐2 expression in the myocardium.

Conclusion:

Intramyocardial injection of VEGF165 cDNA significantly improved cardiac performance, stimulated angiogenesis and reduced cardiomyocyte apoptosis, in a rat model of acute myocardial infarction.
Anaemia and renal function in heart failure due to idiopathic dilated cardiomyopathy
Authors: Inglis Sally C. , Stewart Simon , Papachan Alexander , Vaghela Vinesh , Libhaber Carlos , Veriava Yosuf , Sliwa Karen
Published: January 2007

Background:

Anaemia and renal dysfunction are common in patients with heart failure (HF). Most studies involve western cohorts with ischaemic aetiology receiving treatment likely to impair renal function.

Aims:

To investigate the frequency of anaemia and renal dysfunction and the relationship between the two within a cohort of 163 newly diagnosed Black African idiopathic cardiomyopathy patients prior to commencing HF treatments and compare those findings to those of western HF cohorts.

Methods:

Single‐centre retrospective analysis. Anaemia defined as haemoglobin concentration <13.0 g/dL for males (n=85) and <12 g/dL for females (n=78). Probable renal dysfunction defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m2, using serum creatinine concentrations.

Results:

The mean age was 48±11 years, 52% were male. Overall, 13.5% of patients were anaemic and 11.8% had evidence of renal dysfunction, while 1.2% had both. Renal dysfunction was significantly more common in older patients (mean age 58±13 vs. 47±10 years: p<0.001).

Conclusion:

The frequency of anaemia and renal dysfunction in this cohort was lower than that reported in western HF cohorts. These data infer a more limited relationship between HF, anaemia and renal dysfunction in patients without atherothrombotic disease; hence extrapolation of HF data from the western world to other populations should be interpreted cautiously.
Non‐invasive radial pulse wave assessment for the evaluation of left ventricular systolic performance in heart failure
Authors: Tartiere Jean‐Michel , Logeart Damien , Beauvais Florence , Chavelas Christophe , Kesri Lamia , Tabet Jean‐Yves , Cohen‐solal Alain
Published: January 2007

Introduction

Left ventricular (LV) developed pressure (dP/dt) is a classical index of myocardial contractility related to prognosis during heart failure. We sought to assess the reproducibility and feasibility of use of the maximal first derivative of the radial pulse, Rad dP/dt, as a peripheral criterion of ventricular contractility in patients with heart failure.

Methods

We assessed 50 consecutive, patients with heart failure using aplanation tonometry to record the radial pulse wave and calculate Rad dP/dt. Echocardiography, Doppler flow and tissue Doppler imaging were used to record classical parameters of LV function: LV ejection fraction (LVEF), Tei index, dP/dt on mitral regurgitation (MR dP/dt) and peak systolic velocity (S′). Total systemic vascular resistance (TSVR) was calculated by use of the Doppler calculated cardiac output. Preload was assessed by the E/Ea ratio. Feasibility was tested in an ongoing prospective mortality study (n=310).

Results

The Bland and Altman representation of repeated measurements of the Rad dP/dt showed good agreement. Feasibility was greater than 99% for a successful assessment on the right arm during the first attempt. The Rad dP/dt correlated with the LVEF, S′ or Tei index as usual parameters of impaired contractility but not preload (E/Ea) or afterload (TSVR) parameters. MR dP/dt and Rad dP/dt were closely related (r=0.75, p<0.001). The ability of the arterial dP/dt to characterize LVEF was not modified by adjustment for arterial viscoelastic properties.

Conclusion

The maximal dP/dt of the radial pulse appears to be a valuable and reproducible peripheral criterion of LV systolic performance.
Analgesic treatment and predictors of satisfaction with analgesia in patients with acute undifferentiated abdominal pain
Authors: Marinsek Matej , Kovacic Dragan , Versnik Darja , Parasuh Milena , Golez Slavica , Podbregar Matej
Published: January 2007

The objectives of this prospective, observational cohort study were to examine current practice of analgesia in adults with acute abdominal pain presenting to emergency department (ED), to assess patient—physician agreement on pain severity, and to measure patients’ satisfaction with pain management.

Methods: Emergency room nurse assessed initial patient's and physician's ranking on a 0–100mm visual analogue scale (VAS) as well as patient's VAS rankings 5min, 15min, and 60min after starting treatment for pain, and on discharge. In patients who received no therapy VAS scores were assessed 5min, 15min, and 60min after initial examination, and on discharge. Patient's satisfaction with pain management on discharge from ED was assessed using a four‐point categorical scale in which 1=completely unsatisfied, 2=mostly unsatisfied, 3=mostly satisfied, and 4=completely satisfied.

Results: A total of 185 patients were enrolled. Patients’ mean initial VAS was higher than physicians’ (76±20mm, vs. 59±20mm, p<0.001). Physician's VAS ≥60mm was the sole independent predictor of receiving analgesic therapy (p<0.001). On discharge from ED, 111 patients (60%) were predominantly satisfied with analgesia (satisfaction score ≥3). Drug titration (p=0.026) and decrease in VAS score ≥20mm between initial and discharge score (p<0.001) independently predicted patients’ satisfaction.

Conclusions: Patients with acute abdominal pain rated pain significantly higher than physicians who's pain estimation in turn tailored analgesia. Only 60% of patients were satisfied with analgesia. Analgesic drug titration and a decrease of ≥20mm on VAS predicted patients’ satisfaction.
Exploring retailers’ sensitivity to local sustainability policies
Authors: Quak H.J. , de Koster M.B.M.
Published: January 2007

Local governments in Western Europe increasingly use city time‐access regulations to improve social sustainability. These regulations significantly influence the distribution process of retail chain organizations. This paper studies the impact of governmental time‐window pressure on retailers’ logistical concepts and the consequential financial and environmental distribution performance. We determine which dimensions in the retailer's logistical concept determine its cost and emission sensitivity to increasing time‐window pressure. Our research is based on a multiple case study of fourteen Dutch retail cases in different sectors and with different store formulas. The retailers provided all organizational, flow and cost data of their secondary distribution (between distribution center and stores). We use these data to calculate the impacts of different time‐window pressure scenarios, including the current situation, using vehicle routing software. It appears that cost and emissions increases are moderate, when few cities are affected. However, as more cities are affected, costs and emissions increase considerably, particularly if time‐window lengths become shorter. Time‐windows harmonized between cities lead to fewer negative effects. We find various dimensions that contribute to reducing a retailer's sensitivity to time‐window pressure. We formulate conclusions hypothesizing the links between time‐window pressure, its effects, and the dimensions that determine these effects.
Einflüsse von Computer- und Mediennutzung auf die Persönlichkeitsentwicklung von Kindern und Jugendlichen
Authors: Süss
Published: January 2007

Kinder und Jugendliche entwickeln ihre Persönlichkeit in aktiver Auseinandersetzung mit Medien. Medienkompetenz ist zu einer Entwicklungsaufgabe geworden. Zugleich verändern die Medien die allgemeinen Sozialisationsprozesse wie die Integration in die Peergroup und die Ablösung von den Eltern. Medien können sowohl als Ressourcen wie auch als Risiken für die Entwicklung wirksam werden. Empirische Studien zeigen, dass Kinder einen immer reichhaltigeren Medienzugang haben und viel Zeit mit Bildschirmmedien verbringen. Mediensozialisation wird zwar von den Heranwachsenden zunehmend selbst gesteuert, zur Verhinderung von negativen Medienwirkungen, zum Beispiel Internetsucht, ist aber erzieherische Aufmerksamkeit erforderlich. Wenn der Medienumgang innerhalb einer kinderfreundlichen Lebenswelt stattfindet, dann werden sich Medien nicht negativ auf die Entwicklung der Kinder auswirken.