bluuebunny/crossref_metadata_2025 huggingface dataset:
Melanopsin retinal ganglion cells receive bipolar and amacrine cell synapses
Authors: Belenky Michael A. , Smeraski Cynthia A. , Provencio Ignacio , Sollars Patricia J. , Pickard Gary E.
Published: April 2003

Melanopsin is a novel opsin synthesized in a small subset of retinal ganglion cells. Ganglion cells expressing melanopsin are capable of depolarizing in response to light in the absence of rod or cone input and are thus intrinsically light sensitive. Melanopsin ganglion cells convey information regarding general levels of environmental illumination to the suprachiasmatic nucleus, the intergeniculate leaflet, and the pretectum. Typically, retinal ganglion cells communicate information to central visual structures by receiving input from retinal photoreceptors via bipolar and amacrine cells. Because melanopsin ganglion cells do not require synaptic input to generate light‐induced signals, these cells need not receive synapses from other neurons in the retina. In this study, we examined the ultrastructure of melanopsin ganglion cells in the mouse retina to determine the type (if any) of synaptic input these cells receive. Melanopsin immunoreaction product was associated primarily with the plasma membrane of (1) perikarya in the ganglion cell layer, (2) dendritic processes in the inner plexiform layer (IPL), and (3) axons in the optic fiber layer. Melanopsin‐immunoreactive dendrites in the inner (ON) region of the IPL were postsynaptic to bipolar and amacrine terminals, whereas melanopsin dendrites stratifying in the outer (OFF) region of the IPL received only amacrine terminals. These observations suggested that rod and/or cone signals may be capable of modifying the intrinsic light response in melanopsin‐expressing retinal ganglion cells. J. Comp. Neurol. 460:380–393, 2003. © 2003 Wiley‐Liss, Inc.
Direct input from cochlear root neurons to pontine reticulospinal neurons in albino rat
Authors: Nodal Fernando R. , López Dolores E.
Published: April 2003

The cochlear root neurons (CRNs) are thought to mediate the auditory startle reflex (ASR) in the rat, which is widely used as a behavioral model for the investigation of the sensorimotor integration. CRNs project, among other targets, to the nucleus reticularis pontis caudalis (PnC), a major component of the ASR circuit, but little is known about the organization of this projection. Thus, we injected biotinylated dextran amine (BDA) in CRNs to study their projections with light and electron microscopy. Also, we performed double‐labeling experiments, injecting BDA in the CRNs and subunit B of the cholera toxin or Fluorogold in the spinal cord to verify that CRNs project onto reticulospinal neurons. Electron microscopy of the labeled CRNs axons and terminals showed that even their most central and thinnest processes are myelinated. Most of the terminals are axodendritic, with multiple asymmetric synapses, and contain round vesicles (50 nm diameter). Double‐labeling experiments demonstrated that CRN terminals are apposed to retrogradely labeled reticulospinal neurons in the contralateral nucleus reticularis PnC and bilaterally in the lateral paragigantocellular nucleus. Analyses of serial sections revealed that multiple CRNs synapse on single reticulospinal neurons in PnC, suggesting a convergence of auditory information. The morphometric features of these neurons classify them as giant neurons. This study confirms that CRNs project directly onto reticulospinal neurons and presents other anatomical features of the CRNs that contribute to a better understanding of the circuitry of the ASR in the rat. J. Comp. Neurol. 460:80–93, 2003. © 2003 Wiley‐Liss, Inc.
Optimum filter theory for quasi‐periodic signals
Authors: Nishi Kazuki
Published: April 2003

An optimum filter is designed for separating quasi‐periodic signals (those with amplitude and period changing randomly but a rough periodicity kept) in a noisy environment. In the first half of the paper, a Wiener filter is derived with steadiness assumed in the variations of the amplitude and fundamental frequency. It is shown that the frequency characteristics are (1) comb characteristics of a constant BW (bandwidth) type if only the amplitude variations are taken into consideration, (2) comb characteristics of a constant Q type if only the variations of the fundamental frequency are taken into account, and (3) comb characteristics transitional from a constant BW type to a constant Q type as the harmonic changes from a lower order to a higher order when both are taken into account. In the latter half of the paper, a Kalman filter analysis is carried out for the case in which the statistical nature of the amplitude/fundamental frequency variations is time‐varying. The random nature of the complex phase term is treated as state‐dependent noise. By describing the signal model in terms of the Ito probability differential equation, the Kalman filter equation for the use of this model as a state space model is solved. In particular, it is shown by approximate solution that the center frequency and occupancy bandwidth of each narrow‐band filter are determined to follow the variations of the amplitude and fundamental frequency. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(9): 43–53, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10067
A self‐stabilizing max‐heap protocol in tree networks
Authors: Ukena Satoshige , Hasegawa Manabu , Katayama Yoshiaki , Masuzawa Toshimitsu , Fujiwara Hideo
Published: April 2003

A fault‐tolerant protocol is important in a distributed system consisting of processes that are interconnected in a network. One prominent technique used for implementing fault tolerance is a self‐stabilizing protocol. A self‐stabilizing protocol stabilizes in obtaining a solution regardless of the network status from which execution begins. This property enables a self‐stabilizing protocol to tolerate arbitrary transient faults. This paper uses a self‐stabilizing protocol for implementing interprocess synchronization in a tree network to propose a self‐stabilizing protocol for configuring a heap‐ordered tree. The proposed protocol for configuring the heap‐ordered tree, which has stabilizing time O(h) and space complexity of each process O(K), has improved both the stabilizing time and space complexity compared with other known results (where h is the height of the tree and K is the input size). © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(9): 63–72, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.10109
An occlusion‐robust tracking algorithm based on a spatiotemporal Markov random field model
Authors: Kamijo Shunsuke , Matsushita Yasuyuki , Ikeuchi Katsushi , Sakauchi Masao
Published: April 2003

The tracking of vehicles on images is important as a baseline technology for applying ITS image processing to the detection of abnormal phenomena such as accidents. However, up to now one of the most difficult problems in vehicle tracking has been occlusion, which creates a difficult environment for realizing stable tracking. This has been particularly true in our research, because our objects of study are large intersections in which an average of 20 vehicles are present at the same time, of various sizes and shapes, and so on. The various motions of these vehicles also generate various conditions under which occlusion can occur. In tracking under these circumstances, it is necessary to use a paradigm different from those used previously, which assume a model of rectilinear motion, largely vacant intersections, predictions based on straight‐line trajectories, and specific vehicle shapes. To solve this problem, we developed an algorithm that makes use of the Markov random field (MRF) model, generalized beyond a single image to include temporal sequences of images, and evaluated its degree of accuracy based on spatiotemporal correlation of textures from one image to the one immediately following it and the connection of loci followed by the moving bodies. The results were further optimized by stochastic relaxation of the energy distributions exhibited by images from this space‐time MRF, which makes the tracking robust against various forms of occlusion. We applied this space‐time MRF to image data taken over about 25 minutes, tracking 3214 vehicles moving through an intersection under conditions of heavy congestion. Our results showed that the tracking was successful with a 99% probability when the vehicles being tracked generated no occlusions, while for the 541 cars that did cause occlusions the probability of successfully tracking multiple cars and distinguishing the separate vehicles through the occlusions was 95%. Because this algorithm uses information obtained from black‐and‐white images only, and can be implemented without any prior hypotheses about the vehicle's shape etc., it is useful over long periods of time and under a broad range of conditions. For this reason, we anticipate that it will be effective for detecting accidents and other anomalies in traffic at intersections. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 86(9): 73–86, 2003; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/ecjc.10110
Numerical simulation of disperse multiphase flows with an application in power engineering
Authors: Bernert K. , Frank Th. , Schneider H. , Pachler K.
Published: April 2003

This paper deals with the numerical simulation of two‐phase flows based on the solution of the Navier–Stokes equations with a k–εturbulence model for the gas phase and a particle tracking model of the disperse phase fulfilling the framework of the Eulerian–Lagrangian (PSI‐Cell) approach. The numerical procedures for the two phases are based on the domain decomposition method applied to a block‐structured grid. The complete code is parallelized for computers of MIMD architecture. The paper gives a description of the numerical methods with special attention to the parallelization. Some test calculations demonstrate the performance of the code. The numerical simulation of a flow splitter from the field of power engineering is presented as an example for a real world application of the method. Copyright © 2003 John Wiley & Sons, Ltd.
Candidate‐gene association studies with pedigree data: Controlling for environmental covariates
Authors: Slager S.L. , Schaid D.J. , Wang L. , Thibodeau S.N.
Published: April 2003

Case‐control studies provide an important epidemiological tool to evaluate candidate genes. There are many different study designs available. We focus on a more recently proposed design, which we call a multiplex case‐control (MCC) design. This design compares allele frequencies between related cases, each of whom are sampled from multiplex families, and unrelated controls. Since within‐family genotype correlations will exist, statistical methods will need to take this into account. Moreover, there is a need to develop methods to simultaneously control for potential confounders in the analysis. Generalized estimating equations (GEE) are one approach to analyze this type of data; however, this approach can have singularity problems when estimating the correlation matrix. To allow for modeling of other covariates, we extend our previously developed method to a more general model‐based approach. Our proposed methods use the score statistic, derived from a composite likelihood. We propose three different approaches to estimate the variance of this statistic. Under random ascertainment of pedigrees, score tests have correct type I error rates; however, pedigrees are not randomly ascertained. Thus, through simulations, we test the validity and power of the score tests under different ascertainment schemes, and an illustration of our methods, applied to data from a prostate cancer study, is presented. We find that our robust score statistic has estimated type I error rates within the expected range for all situations we considered whereas the other two statistics have inflated type I error rates under nonrandom ascertainment schemes. We also find GEE to fail at least 5% of the time for each simulation configuration; at times, the failure rate reaches above 80%. In summary, our robust method may be the only current regression analysis method available for MCC data. Genet Epidemiol 24:273–283, 2003. © 2003 Wiley‐Liss, Inc.
A new spatio‐temporal measurement method using high‐resolution processing
Authors: Quiniou Thomas , El Zein Ghaïs
Published: April 2003

A new application for the high‐resolution processing algorithm MUSIC, applied to a rotating antenna, is presented. Experimental results show that significant improvement can be achieved using the proposed method, compared to a low‐directivity rotating antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 329–330, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10909
Self‐scaling properties of the reflection coefficient of Cantor prefactal multilayers
Authors: Chiadini F. , Fiumara V. , Pinto I. M. , Scaglione A.
Published: April 2003

We highlight the self‐similar features of the frequency‐dependent (absolute) reflection coefficient of a dielectric Cantor prefractal obtained by applying the well‐known Cantor‐set construction to the optical (rather than physical) layer lengths. The referred properties are first obtained using an exact characteristic matrix representation of the reflection coefficient and then resorting to an (accurate) small‐reflection approximation. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 339–343, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10912
Analytical signal formalism in the description of optical pulse photodetection
Authors: Fraile‐Peláez F. Javier
Published: April 2003

In this paper, we unveil and discuss a theoretical misconception in a classical formalism of Gaussian pulse envelope propagation. With simple analytical arguments, we explain the mistake and develop a universal result, valid for short and ultra‐short optical pulses of arbitrary shape. This general result sheds light on the mathematical separation of a pulse into its envelope (energy) and its coherent characteristics (frequency chirp). With it, a theoretical ground is provided for the use of blind numerical computations to calculate complex photodetected pulse shapes. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 347–352, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10914
Experimental studies of the dual‐band planar inverted‐F antenna with a U‐shaped slot
Authors: Row Jeen‐Sheen
Published: April 2003

This paper presents experimental demonstrations of a dual‐band planar inverted‐F antenna loaded with a U‐shaped slot. The physical parameters of the antenna, including shorted‐strip widths and ground‐plane dimensions, are studied in detail and their effects on the center frequencies and bandwidths of two operating bands are shown. The purpose of this paper is to achieve a compact dual‐band antenna for wireless local network applications. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 359–361, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10917
Interference‐free optical power delivery for electronics modules
Authors: Lazarus M. J. , Holt S. , Giltrow M. , Campbell D. , Ingles D. , Cheung K. Y.
Published: April 2003

The elimination of electromagnetic pickup and interference for microcircuits is demonstrated by replacing the wired power connection with a plastic optical fibre and a photo‐voltaic converter. The coupling of light from an inexpensive source to the fibre is facilitated easily with a plastic bulb‐lens antenna. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 361–364, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10918
Measuring arterial stiffness in diabetic patients
Authors: Woodman RJ , Watts GF
Published: April 2003

The excess risk of cardiovascular disease in patients with type 2 diabetes mellitus remains largely unexplained. Arterial stiffness, an early feature of diabetic vasculopathy involving several mechanisms, results in impaired arterial compliance, which has recently been proposed as a powerful independent predictor of cardiovascular disease. Decreased arterial compliance can contribute to the development and progression of hypertension, left ventricular hypertrophy and dysfunction, and decreased myocardial perfusion, all of which are highly prevalent in type 2 diabetes mellitus. Arterial compliance has been demonstrated to be impaired in type 2 diabetes using several different technically demanding methods. An increase in the demand by clinical researchers for measurement of arterial compliance has led to the development and commercial availability of highly practicable techniques. These each utilise different aspects of the pulse pressure waveform, are simple and reliable and reflect both large and small vessel compliance, both of which are impaired in type 2 diabetes. They offer new tools for identifying patients at increased risk of developing cardiovascular complications, including those with established diabetes. In this article we introduce the reader to the concept of arterial stiffness, the significance of arterial stiffness for diabetes and the new techniques that may potentially be useful in a research or clinical setting. Copyright © 2003 John Wiley & Sons, Ltd.
Effect on respiratory function of pressure support ventilation versus synchronised intermittent mandatory ventilation in preterm infants
Authors: Migliori Claudio , Cavazza Alessandra , Motta Mario , Chirico Gaetano
Published: April 2003

Our objective was to compare the effects of pressure support ventilation and synchronized intermittent mandatory ventilation on respiratory function in preterm babies. Twenty preterm infants (mean gestational age, 29 weeks; mean weight at study, 1,354 g) were evaluated. Patients received two repeated cycles of synchronized intermittent mandatory ventilation, alternated with pressure support ventilation, for a total of four alternated phases, each phase lasting 4 hr. Spontaneous respiratory rate, tidal volume, minute volume, and mean airway pressure were recorded hourly. The tidal volume released by the ventilator was limited to 6 ml/kg. During the two pressure support ventilation phases, a statistically significant reduction of respiratory rate and a significant increase of tidal and minute volume were noted, as compared to the two synchronized intermittent mandatory ventilation periods. Mean airway pressure significantly increased only after the first shift from synchronized intermittent mandatory ventilation to pressure support ventilation. The changes of minute volume and respiratory rate observed during pressure support ventilation did not persist after the return to synchronized intermittent mandatory ventilation. In conclusion, pressure support ventilation, as compared to synchronized intermittent mandatory ventilation, seemed to improve respiratory function in preterm infants. Pediatr Pulmonol. 2003; 35:364–367. © 2003 Wiley‐Liss, Inc.
Blocking leukocyte influx and function to prevent chronic lung disease of prematurity
Authors: Auten Richard L. , Ekekezie Ikechukwu I.
Published: April 2003

Inflammation is strongly linked to the pathogenesis of chronic lung disease of prematurity (CLD). Premature gas‐breathing of ambient or supplemental oxygen in a host with relatively deficient and poorly inducible antioxidant defenses may itself be injurious, and further amplified by mechanical stretch injury in the surfactant‐insufficient lung.1 Cellular injury provokes an inflammatory response.

Since inflammation is often detected at birth in the lungs of newborns who later develop CLD,2 it has been an attractive strategy to abrogate inflammation, but the arsenal is limited. Glucocorticoids have been widely used but are acknowledged to be potentially harmful to neurologic and somatic development, and are not recommended outside controlled trials.3 The number that benefit is comparable to the number harmed, according to meta‐analysis.4 More specific blockade of harmful inflammation could overcome this obstacle. Examination of the inflammatory pathways that initiate and propagate lung injury and subsequent abnormal development points to promising new strategies that may one day be tailored to individual patients. Pediatr Pulmonol. 2003; 35:335–341. © 2003 Wiley‐Liss, Inc.
Quantum chemical study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine. Part 3. Properties of intermediates during hydride transfer
Authors: Li Ming , Zheng Wenxu , Tian Anmin
Published: April 2003

In the current article, the structures and properties of intermediates during the hydride transfer for the prior coordination of the carbonyl oxygen of keto oxime ether at B(2) of oxazaborolidine are discussed. All the structures are optimized completely by means of the Hartree–Fock (HF) and the density functional methods at the HF/6‐31G(d) and Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar (B3LYP)/6‐31G(d) levels. The hydride transfer from BH3 to the carbonyl carbon in oxazaborolidine‐borane‐keto oxime ether adduct results in the formation of the adduct 4a* with a seven‐membered ring. This adduct has four stable structures. Another hydride of BH2 transfers to the oxime carbon in 4a*, leading to the adduct 5a*, which has also four stable structures. Among all the structures of 5a*, the most stable structure can generate (1S, 2R)‐cis amino alcohol, which is in agreement with that obtained in the experiment. This enantioselective reduction may go through the process in which oxazaborolidine‐borane‐keto oxime ether adduct is directly transformed into the adduct 4a* with a seven‐membered ring. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 307–316, 2003
Spin preference in twenty‐valence electron systems of form XCCY
Authors: Trindle Carl
Published: April 2003

Linear molecules with degenerate and partially occupied orbitals may seek a ground state of high symmetry and spin multiplicity, or may break symmetry and favor a low‐spin state. From studies of OCCO and SCCS it is clear that thermodynamic stability is affected by (valence shell) isolelectronic substitution. Here is described the structure, preference of spin state, and stability of a family of compounds derived by isolobal and isoelectronic analogy from OCCO. The Complete Active Space Self Consistent (CASSCF) methods are used to assure a qualitatively correct description of the multiconfigurational states of the highest symmetry species and balanced description of states of differing spin multiplicity. The results suggest three rules of design and identify several small molecules worthy of experimental investigation. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 286–293, 2003
Differential gene expression in the rat caudate putamen after “binge” cocaine administration: Advantage of triplicate microarray analysis
Authors: Yuferov Vadim , Kroslak Thomas , Laforge K. Steven , Zhou Yan , Ho Ann , Kreek Mary Jeanne
Published: April 2003

Rat genome U34A (Affymetrix®) oligonucleotide microarrays were used to analyze changes in gene expression in the caudate putamen (CPu) of Fischer rats induced by 1 and 3 days of “binge” cocaine (or saline) administration. A triplicate array assay of pooled RNA of each treatment group was used to evaluate the technical variability and sensitivity of microarrays. Cocaine‐regulated genes were identified using the Affymetrix MAS 5.0 and Data Mining Tool v. 3. Eighty‐nine upregulated and eight downregulated genes/ESTs were found after 1 day of “binge” cocaine. Following 3 days of cocaine treatment we identified 21 upregulated and 17 downregulated genes/ESTs. RNase protection assays of selected genes confirmed reliability of changes identified by the microarrays at the level of ≥1.40‐fold increase. Many genes upregulated in the CPu by cocaine were immediate early genes for transcription factors and for “effector” proteins (e.g., vesl/Homer1a, Arc, synaptotagmin IV). Acute “binge” cocaine also increased mRNA levels for glutamate receptor GluR2, dopamine receptor D1, and a number of phosphatases. Genes downregulated by cocaine include several genes associated with energy metabolism in mitochondria, as well as the phosphatydylinositol‐4 kinase and the regulator of G‐protein signaling protein 4 (RGS4). A differential expression of somatostatin receptor SSTR2, not known to be a cocaine‐responsive gene, as well as the clock gene Per2, were found by microarrays and confirmed by RNase protection assay. These results demonstrate the potential of microarrays in profiling gene expression with ≥40% increase or ≥14% decrease in mRNA levels for discovery of novel cocaine‐responsive genes. Synapse 48:157–169, 2003. © 2003 Wiley‐Liss, Inc.
Structural study of a single‐point mutant of Sulfolobus solfataricus alcohol dehydrogenase with enhanced activity
Authors: Esposito Luciana , Bruno Ilaria , Sica Filomena , Raia Carlo Antonio , Giordano Antonietta , Rossi Mosè , Mazzarella Lelio , Zagari Adriana
Published: April 2003

Alcohol dehydrogenase from Sulfolobus solfataricus (SsADH) is the only enzyme from Archaea among the structurally studied members of the medium‐chain ADH family described so far. Here, we present the three‐dimensional structure of the apo form of the mutant N249Y which exhibits increased catalytic activity when compared to the wild‐type enzyme. The substitution, located in the coenzyme binding domain, decreases the affinity for NAD(H) cofactor. The rearrangement of segments 248–250 and 270–275, induced by the mutation, suggests an explanation for the lower coenzyme affinity. This study also highlights the role in SsADH catalysis of the flexible loops located at the interface between the catalytic and the coenzyme domains.
The acarbose‐biosynthetic enzyme AcbO from Actinoplanes sp. SE 50/110 is a 2‐epi‐5‐epi‐valiolone‐7‐phosphate 2‐epimerase
Authors: Zhang Chang-Sheng , Podeschwa Michael , Altenbach Hans-Josef , Piepersberg Wolfgang , Wehmeier Udo F
Published: April 2003

The C7‐cyclitol 2‐epi‐5‐epi‐valiolone is the first precursor of the cyclitol moiety of the α‐glucosidase inhibitor acarbose in Actinoplanes sp. SE50. The 2‐epi‐5‐epi‐valiolone becomes phosphorylated at C7 by the ATP dependent kinase AcbM prior to the next modifications. Preliminary data gave evidences that the AcbO protein could catalyse the first modification step of 2‐epi‐5‐epi‐valiolone‐7‐phosphate. Therefore, the AcbO protein, the encoding gene of which is also part of the acbKMLNOC operon, was overproduced and purified. Indeed the purified protein catalysed the 2‐epimerisation of 2‐epi‐5‐epi‐valiolone‐7‐phosphate. The chemical structure of the purified reaction product was proven by nuclear magnetic resonance spectroscopy to be 5‐epi‐valiolone‐7‐phosphate.
Interaction of Sedlin with chloride intracellular channel proteins
Authors: Fan Libin , Yu Wei , Zhu Xueliang
Published: April 2003

Sedlin is an evolutionarily conserved protein encoded by the causative gene SEDL for spondyloepiphyseal dysplasia tarda. Nevertheless, how Sedlin mutations cause the disease remains unknown. Here, the intracellular chloride channel protein CLIC1 was shown to associate with Sedlin by yeast two‐hybrid screening. Green fluorescence protein‐CLIC1 readily co‐immunoprecipitated with FLAG‐Sedlin. In addition, both proteins colocalized extensively in cytoplasmic vesicular/reticular structures in COS‐7 cells, suggesting their interaction at intracellular membranous organelles. Sedlin also associated with CLIC2 in yeast two‐hybrid assays. The link between Sedlin and the intracellular chloride channels is the first step to understand their functional interplays.
Wheat gliadin induces apoptosis of intestinal cells via an autocrine mechanism involving Fas–Fas ligand pathway
Authors: Giovannini Claudio , Matarrese Paola , Scazzocchio Beatrice , Varı̀ Rosaria , D’Archivio Massimo , Straface Elisabetta , Masella Roberta , Malorni Walter , De Vincenzi Massimo
Published: April 2003

Wheat gliadin and other cereal prolamins have been said to be involved in the pathogenic damage of the small intestine in celiac disease via the apoptosis of epithelial cells. In the present work we investigated the mechanisms underlying the pro‐apoptotic activity exerted by gliadin‐derived peptides in Caco‐2 intestinal cells, a cell line which retains many morphological and enzymatic features typical of normal human enterocytes. We found that digested peptides from wheat gliadins (i) induce apoptosis by the CD95/Fas apoptotic pathway, (ii) induce increased Fas and FasL mRNA levels, (iii) determine increased FasL release in the medium, and (iv) that gliadin digest‐induced apoptosis can be blocked by Fas cascade blocking agents, i.e. targeted neutralizing antibodies. This favors the hypothesis that gliadin could activate an autocrine/paracrine Fas‐mediated cell death pathway. Finally, we found that (v) a small peptide (1157 Da) from durum wheat, previously proposed for clinical practice, exerted a powerful protective activity against gliadin digest cytotoxicity.
Identification of 14 new phosphoproteins involved in important plant mitochondrial processes
Authors: Bykova Natalia V. , Egsgaard Helge , Møller Ian M.
Published: April 2003

Protein phosphorylation is a very important posttranslational modification the role of which is practically unexplored in mitochondria. Using two‐dimensional gel electrophoresis followed by mass spectrometry, 14 new phosphoproteins are identified in potato tuber mitochondria, all household proteins also present in mammalian and fungal mitochondria. Seven of the new phosphoproteins are involved in the tricarboxylic acid cycle or associated reactions, four are subunits of respiratory complexes and involved in electron transport, ATP synthesis and protein processing, two are heat shock proteins and one is involved in defence against oxidative stress. These findings open up entirely new possibilities for the regulation and signal integration of mitochondrial processes.
Selective cytotoxicity following Arg‐to‐Lys substitution in tritrpticin adopting a unique amphipathic turn structure
Authors: Yang Sung-Tae , Shin Song Yub , Lee Chul Won , Kim Yong-Chul , Hahm Kyung-Soo , Kim Jae Il
Published: April 2003

In antimicrobial peptides, the cationic property due to basic amino acids has been widely recognized as an important factor to promote electrostatic interaction with negatively charged phospholipids. However, little is known about the differences between two basic residues, Arg and Lys, in membrane binding affinity. Tritrpticin is an Arg‐ or Trp‐rich antimicrobial peptide with a broad spectrum of antibacterial and antifungal activity. To investigate the structural and functional differences between Arg and Lys residues, here we designed and synthesized Arg‐containing peptides, tritrpticin and SYM11, and their counterpart Lys‐substituted peptides, TRK and SYM11KK, respectively. Although there were no remarkable conformational differences between Arg‐containing and Lys‐substituted peptides, TRK and SYM11KK exhibited almost two‐fold enhanced antibacterial activity but significantly reduced hemolytic activity as compared to tritrpticin and SYM11, respectively. Furthermore, Arg‐containing peptides showed strong binding affinity to both zwitterionic and anionic liposomes, whereas Lys‐substituted peptides interacted weakly with zwitterionic liposomes but strongly with anionic liposomes. These results suggest that the primary amine of Lys interacts less electrostatically with zwitterionic phospholipids than the guanidinium group of Arg. Our results obtained in this study may be helpful in the design of drugs that target negatively charged phospholipids.
Effect of dynamic hydrostatic pressure on rabbit intervertebral disc cells
Authors: Kasra Mehran , Goel Vijay , Martin James , Wang Shea‐Tien , Choi Woosung , Buckwalter Joseph
Published: April 2003

The pathogenesis of vibration‐induced disorders of intervertebral disc at the cellular level is largely unknown. The objective of this study was to establish a method to investigate the ranges of constructive and destructive hydrostatic loading frequencies and amplitudes in preventing or inducing extracellular disc matrix degradation. Using a hydraulic chamber, normal rabbit intervertebral disc cells were tested under dynamic hydrostatic loading. Monolayer cultures of disc outer annulus cells and 3‐dimensional (3‐D) alginate cultures of disc nucleus pulposus cells were tested. Effects of different loading amplitudes (3‐D culture, 0–3 MPa; monolayer, 0–1.7 MPa) and frequencies (1–20 Hz) on disc collagen and protein metabolism were investigated by measuring 3H‐proline‐labeled proteins associated with the cells in the extracellular matrix and release of 3H‐proline‐labeled molecules into culture medium. High frequency and high amplitude hydrostatic stress stimulated collagen synthesis in cultures of outer annulus cells whereas the lower amplitude and frequency hydrostatic stress had little effect. For the same loading duration and repetition, neither treatment significantly affected the relative amount of protein released from the cell layers, indicating that protein degradation and stability were unaffected. In the 3‐D nucleus culture, higher amplitude and frequency increased synthesis rate and lowered degradation. In this case, loading amplitude had a stronger influence on cell response than that of loading frequency. Considering the ranges of loading amplitude and frequency used in this study, short‐term application of high loading amplitudes and frequencies was beneficial in stimulation of protein synthesis and reduction of protein degradation. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Women's Health after a First Myocardial Infarction: A Comprehensive Perspective on Recovery Over a 4-Year Period
Authors: Wickholm Maritha , Fridlund Bengt
Published: April 2003

Background: Little attention has so far been focused on follow ups of women's long-term recovery after a myocardial infarction (MI), especially from a comprehensive perspective. Aim: The aim of this study was to prospectively determine women's self-rated health after a first MI from a comprehensive perspective on recovery over a 4-year period. Methods: Consecutively chosen women ( n = 240) who had suffered a first MI were asked to complete a self-rated questionnaire regarding health (including not only biophysical, but also behavioral, emotional, social and working conditions) before being discharged from hospital as well as 1 and 4 years later. The results were analyzed by descriptive and inferential statistics. Results: Health improvements, especially during the first year, could be observed in the women's behavioral condition regarding their attitude to diet consciousness, exercise, simultaneous capability and smoking behavior as well as in the emotional condition regarding their stressful life events, depressed mood and loss of control. In the social condition, the women considered that the healthcare professionals had improved their support over time as well as treating the women's complaints more seriously. Regarding the working condition, the women felt that they were being controlled at work, especially during the first year after the MI. Conclusions: Based on a comprehensive perspective on women's recovery after a first MI, a favorable development of the women's health was observed in the behavioral and emotional conditions while deterioration in the social and working conditions was observed over time. Thus, further efforts are needed in the two latter conditions by means of further studies in combination with greater support from healthcare professionals.
Corrections to Fluid Dynamics
Authors: Streater R. F.
Published: April 2003

We show that a Galilean invariant version of fluid dynamics can be derived by the methods of statistical dynamics using Maxwell's balance equations. The basic equation is non-local, and might replace the Boltzmann equation if the latter turns out not to have global smooth solutions in general. As an approximation, a local form of the equations of motion is derived. It turns out to be a version of the Navier-Stokes system, obeying the Stokes relation, and with the viscosity coefficient rising as Θ1/2 with temperature Θ. The new feature is the presence of the Dufour effect for a gas of a single component. This ensures that the principal symbol of the parabolic system is non-singular.
Durability of Serologic Response After Lamivudine Treatment of Chronic Hepatitis B
Authors: Dienstag Jules L. , Cianciara Janusz , Karayalcin Selim , Kowdley Kris V. , Willems Bernard , Plisek Stanilav , Woessner Mary , Gardner Stephen , Schiff Eugene
Published: April 2003

Forty subjects with chronic hepatitis B and hepatitis B e antigen (HBeAg) seroconversion following lamivudine therapy in previous trials were monitored after treatment to assess the durability of serologic responses. Patient follow–up began a median of 4.3 months after completion of therapy in previous trials. At months 2, 4, 6, 9, and 12 of year 1, and every 6 months thereafter, we tested for HBeAg and hepatitis B surface antigen (HBsAg), hepatitis B virus (HBV) DNA, and alanine aminotransferase (ALT). After a median (range) of 36.6 (4.8–45.6) months of follow–up monitoring, HBeAg seroconversion was demonstrated at the last visit by 77% (30 of 39) of patients. In a post hoc analysis of a slightly different population of all 65 patients with HBeAg seroconversion in previous trials, the 3–year durability of HBeAg seroconversion measured from the time immediately after discontinuing lamivudine therapy was 64%. Nine (9 of 40, 23%) patients were HBsAg negative at the last assessment. Seventy–four percent (17 of 23) of patients with baseline undetectable HBV DNA and normal ALT maintained these responses at the last visit. Eight patients (8 of 40, 20%) initiated retreatment for reappearance of HBV markers, and 7 showed biochemical and/or virologic improvement (including regained HBeAg seroconversion in 2). No safety issues of concern emerged. In conclusion, most HBeAg responses achieved during lamivudine therapy were durable, and most responders experienced prolonged clinical benefit after HBeAg seroconversion and subsequent discontinuation of lamivudine. Lamivudine retreatment for reappearance of hepatitis B markers can achieve resumption of viral suppression. (Hepatology 2003;37:748–755.)
Spontaneous Bacterial Peritonitis in Asymptomatic Outpatients With Cirrhotic Ascites
Authors: Evans Luke T. , Kim Ray W. , Poterucha John J. , Kamath Patrick S.
Published: April 2003

The prevalence and natural history of spontaneous bacterial peritonitis in asymptomatic patients with ascites secondary to cirrhosis is unknown. From a prospectively recorded database, we reviewed the clinical and laboratory features of all outpatients with cirrhotic ascites undergoing paracentesis between July 1994 and December 2000. The prevalence of spontaneous bacterial peritonitis in the population of 427 cirrhotic outpatients as defined by neutrocytic ascites (absolute neutrophil count ≥250 cells/mm3) was 3.5%. Of the 15 patients with neutrocytic ascites, 6 were culture positive (1.4%) and 9 culture negative (2.1%). Eight other patients (1.9%) had bacterascites. The organisms cultured from ascitic fluid in these asymptomatic patients with culture positive neutrocytic ascites and bacterascites were predominantly gram positive. No patient developed hepatorenal syndrome, and 1–year survival of 67% was better than historical data from hospitalized patients with spontaneous bacterial peritonitis. Moreover, patients who did not receive antibiotics for neutrocytic ascites fared no worse than patients who did receive antibiotics. In conclusion, spontaneous bacterial peritonitis in outpatients with cirrhotic ascites is less frequent, occurs in patients with less advanced liver disease, and may have a better outcome than its counterpart in hospitalized patients. In addition, the organisms cultured from ascitic fluid in outpatients are predominantly gram positive. A reassessment of diagnostic criteria for spontaneous bacterial peritonitis in outpatients may be required. (Hepatology 2003;37:897–901.)
Changes in Mitochondrial Adenine Nucleotides and in Permeability Transition in Two Models of Rat Liver Regeneration
Authors: Hernández-Muñoz Rolando , Sánchez-Sevilla Lourdes , Martínez-Gómez Alejandro , Dent Myrna A.R.
Published: April 2003

Although enhanced phosphorylative activity can be a requisite for later DNA synthesis during liver regeneration (LR), mitochondrial generation of reactive oxygen species could lead to altered mitochondrial membrane permeability during the prereplicative phase of LR. Therefore, the role of mitochondrial permeability transition (MPT) was evaluated during rat LR, induced by either partial hepatectomy (PH) or after CCl4 administration. Parameters indicative of mitochondrial function and membrane potentials, those of oxidative stress, and in vivo changes of the intramitochondrial pool of adenine nucleotides were determined. Twelve hours after PH, mitochondrial oxidative and phosphorylative activities and adenosine diphosphate (ADP) content were increased, reaching a maximal peak at 24 hours after surgery (maximal DNA synthesis). Parameters suggestive of oxidant stress were enhanced, but mitochondrial volume and membrane electrical potential remained unaltered. Interestingly, moderate mitochondrial swelling and depolarization were found at later post–PH times (72 hours). In CCl4–treated animals, it was found that an active liver cell necrosis delayed mitotic activity and mitochondrial uncoupled respiration. Starting 12 hours after CCl4 intoxication, a drastic increase of inorganic phosphate occurred within swollen and strongly depolarized mitochondria, suggesting changes in the MPT. Despite expression of messenger RNA (mRNA) for mitochondrial transcription, factor A showed a similar time course in both experimental models. The so–called augmenter liver regeneration was found significantly elevated only in PH rats. In conclusion, onset of MPT could be associated with cell necrosis and inflammation after CCl4 treatment, whereas this mitochondrial event could constitute a putative effector mechanism, through which growth or inflammatory factors inhibiting cell proliferation could initiate LR termination. (Hepatology 2003;37:842–851.)
Inhibition of Hepatitis B Virus Expression and Replication by Rna Interference
Authors: Shlomai Amir , Shaul Yosef
Published: April 2003

RNA interference (RNAi) is the process of sequence–specific gene silencing, initiated by double–stranded RNA (dsRNA) that is homologous in sequence to the target gene. Because it has been shown that RNAi can be accomplished in cultured mammalian cells by introducing small interfering RNAs (siRNAs), much effort has been invested in exploiting this phenomenon for experimental and therapeutic means. In this study, we present a series of experiments showing a significant reduction in hepatitis B virus (HBV) transcripts and proteins in cell culture, as well as in the viral replicative forms, induced by siRNA–producing vectors. The antiviral effect is sequence–specific and does not depend on active viral replication. In conclusion, our data suggest that RNAi may provide a powerful therapeutic tool, acting both on replication–competent and on replication–incompetent HBV. (Hepatology 2003;37:764–770.)
Induced Hyperammonemia Alters Neuropsychology, Brain Mr Spectroscopy and Magnetization Transfer in Cirrhosis
Authors: Balata Sherzad , Olde Damink Steven W.M. , Ferguson Karen , Marshall Ian , Hayes Peter C. , Deutz Nicolaas E.P. , Williams Roger , Wardlaw Joanna , Jalan Rajiv
Published: April 2003

Hyperammonemia is a universal finding after gastrointestinal hemorrhage in cirrhosis. We administered an oral amino acid solution mimicking the hemoglobin molecule to examine neuropsychological changes, brain glutamine levels, and brain magnetization transfer ratio (MTR). Forty–eight metabolically stable patients with cirrhosis and no evidence of “overt” hepatic encephalopathy (HE) were randomized to receive 75 g of amino acid solution or placebo; measurements were performed before and 4 hours after administration. Neuropsychological tests included the Trails B Test, Digit Symbol Substitution Test, memory subtest of the Randt battery, and reaction time. Plasma was collected for ammonia and amino acid measurements, and brain metabolism was studied using proton magnetic resonance (MR) spectroscopy in the first 16 randomized patients. In 7 other patients, MTR was measured. A significant increase in ammonia levels was observed in the amino acid group (amino acid group, 76 ± 7.3 to 121 ± 6.4 μmol/L; placebo, 83 ± 3.3 to 78 ± 2.9 μmol/L; P < .001). Neuropsychological function improved significantly in the placebo group, but no significant change in neuropsychological function was observed in the amino acid group. Brain glutamate/glutamine (Glx)/creatine (Cr) ratio increased significantly in the amino acid group. MTR decreased significantly from 30 ±2.9 to 23 ± 4 (P < .01) after administration of the amino acid solution. In conclusion, an improvement in neuropsychological test results followed placebo, which was not observed in patients administered the amino acid solution. Induced hyperammonemia resulted in an increase in brain Glx/Cr ratio and a decrease in MTR, which may indicate an increase in brain water as the operative mechanism. (Hepatology 2003;37:931–939.)
Regulation of placental nutrient transport and implications for fetal growth
Authors: Bell Alan W , Ehrhardt Richard A
Published: April 2003

Fetal macronutrient requirements for oxidative metabolism and growth are met by placental transport of glucose, amino acids, and, to a lesser extent that varies with species, fatty acids. It is becoming possible to relate the maternal–fetal transport kinetics of these molecules in vivo to the expression and distribution of specific transporters among placental cell types and subcellular membrane fractions. This is most true for glucose transport, although apparent inconsistencies among data on the roles and relative importance of the predominant placenta glucose transporters, GLUT-1 and GLUT-3, remain to be resolved. The quantity of macronutrients transferred to the fetus from the maternal bloodstream is greatly influenced by placental metabolism, which results in net consumption of large amounts of glucose and, to a lesser extent, amino acids. The pattern of fetal nutrient supply is also altered considerably by placental conversion of glucose to lactate and, in some species, fructose, and extensive transamination of amino acids. Placental capacity for transport of glucose and amino acids increases with fetal demand as gestation advances through expansion of the exchange surface area and increased expression of specific transport molecules. In late pregnancy, transport capacity is closely related to placental size and can be modified by maternal nutrition. Preliminary evidence suggests that placental expression and function of specific transport proteins are influenced by extracellular concentrations of nutrients and endocrine factors, but, in general, the humoral regulation of placental capacity for nutrient transport is poorly understood. Consequences of normal and abnormal development of placental transport functions for fetal growth, especially during late gestation, and, possibly, for fetal programming of postnatal disorders, are discussed.