bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrastructural and permeability features of microvessels in the periventricular area of senescence‐accelerated mice (SAM)
Authors: Ueno Masaki , Sakamoto Haruhiko , Kanenishi Kenji , Onodera Masayuki , Akiguchi Ichiro , Hosokawa Masanori
Published: August 2002

Brain transfer of intravenously injected horseradish peroxidase (HRP) and the ultrastructural features of the vessels were examined in periventricular areas in senescence‐accelerated mice (SAMP8), which show age‐related deficits in learning and memory, and senescence‐accelerated resistant mice (SAMR1), which do not show age‐related deficits. In all mice examined with light microscopy, staining reaction for HRP was seen in the periventricular area adjacent to the medial side of the lateral ventricle. Electron microscopic examination in the periventricular area of young and old mice of both strains showed that the staining reaction for HRP appeared in the vesicular profiles of the endothelial cytoplasm, the cytoplasm of the perivascular cells, the basal lamina, and the adjoining extracellular spaces of the white matter, suggesting an incomplete blood–brain barrier (BBB) in the periventricular white matter. In addition, irregularly thickened endothelial cell cytoplasm, membranous inclusions within the basal lamina, and electron‐dense endothelial cell cytoplasm were occasionally seen in aged SAMP8 mice. These findings were not observed in 3‐month‐old SAMP8 mice and 3‐ and 13‐month‐old SAMR1 mice. Perivascular collagen deposits were also frequently seen in aged SAMP8 mice. These findings indicate that the endothelial cells and pericytes in the periventricular white matter in aged SAMP8 mice have an ultrastructure with damaged BBB function. Intravascular substances can easily penetrate the periventricular white matter and the BBB of the vessels in the area can be deteriorated with aging in SAMP8 mice. Microsc. Res. Tech. 53:232–238, 2001. © 2001 Wiley‐Liss, Inc.
III. Chemokines and other mediators, 8. Chemokines and their receptors in cell‐mediated immune responses in the lung
Authors: Matsukawa Akihiro , Lukacs Nicholas W. , Hogaboam Cory M. , Chensue Stephen W. , Kunkel Steven L.
Published: August 2002

Chemokines constitute a large family of chemotactic cytokines that belong to a super‐gene family of 8–10 kDa proteins. The chemokines are considered to be primarily beneficial in host defense against invading pathogens. However, the reactions induced by chemokines can be occasionally excessive, resulting in a harmful response to the host. Recent studies in chemokine biology have elucidated that chemokines are involved in the initiation, development, and maintenance of numbers of diseases including lung diseases. In addition to its chemotactic activity, evidence suggests that chemokines can modify the outcome of the cell‐mediated immune responses by altering the Th1/Th2 cytokine profile. Chemokines are also capable of dictating the direction of specific immune responses. Chemokine action is mediated by a large super‐family of G‐protein coupled receptors, and the receptors are preferentially expressed on Th1/Th2 cells. Certain chemokine receptors are constitutively expressed in immune surveying cells such as dendritic cells and naive T cells. The corresponding chemokines are present in normal lymphoid tissues, suggesting a role of chemokines/receptors in cell homing and cell‐cell communication in lymphoid tissue that can be an initial step for immune recognition. Thus, comprehension of the chemokine biology in immune responses appears to be fundamental for understanding the pathogenesis of T cell–mediated immune responses. The following review will highlight the current insight into the role of chemokines and their receptors in the cell‐mediated immune response, with a special focus on lung diseases. Microsc. Res. Tech. 53:298–306, 2001. © 2001 Wiley‐Liss, Inc.
IV. Clinical aspects of delayed hypersensitivity in lungs: Pathophysiology of hypersensitivity disorders in clinics
Authors: Hirata Kazuto , Kanazawa Hiroshi , Kamoi Hiroshi
Published: August 2002

Hypersensitivity pneumonitis (HP) is an immunologically mediated lung disease of inhaled antigens. HP is not a uniform disease but rather a clinical complex syndrome characterized by varying intensities of responsiveness to different organic antigens. The main aetiological agents include thermophilic bacteria, fungi, animal proteins, and chemical compounds. A combination of host and environmental factors should be considered as a requisite to developing this disease. Although the antigens differ widely, the clinical syndromes that results are very similar. HP occurs mainly in non‐smokers, and clinically it may be in acute, subacute, or chronic forms. The diagnosis of HP requires a constellation of clinic, radiographic, physiologic, pathologic, and immunologic criteria. HP is characterized by a diffuse and predominantly mononuclear cell inflammation, a partly granulomatous, immune disorder of alveolar regions that often involves the small airway. A strong evidence supports that delayed cell‐mediated hypersensitivity mechanisms play a role in pathogenesis of HP. Studies performed on lung cells have demonstrated that cells bearing suppressor/cytotoxic phenotype characterize the lymphocytic alveolitis in patients with hypersensitivity pneumonitis. And also recently evidence has been provided indicating that a prominent role of T‐helper 1 cell‐mediated hypersensitivity with an imbalance in T‐lymphocyte subsets, although the deposit of immune complex may participate in an acute form of the disease as well as in the early phase of the chronic form. Microsc. Res. Tech. 53:307–312, 2001. © 2001 Wiley‐Liss, Inc.
Dynamics and plasticity of peptidergic control centres in the retino‐brain‐pituitary system of Xenopus laevis
Authors: Kramer B.M.R. , Kolk S.M. , Berghs C.A.F.M. , Tuinhof R. , Ubink R. , Jenks B.G. , Roubos E.W.
Published: August 2002

This review deals particularly with the recent literature on the structural and functional aspects of the retino‐brain‐pituitary system that controls the physiological process of background adaptation in the aquatic toad Xenopus laevis. Taking together the large amount of multidisciplinary data, a consistent picture emerges of a highly plastic system that efficiently responds to changes in the environmental light condition by releasing POMC‐derived peptides, such as the peptide α‐melanophore‐stimulating hormone (α‐MSH), into the circulation. This plasticity is exhibited by both the central nervous system and the pituitary pars intermedia, at the level of molecules, subcellular structures, synapses, and cells. Signal transduction in the pars intermedia of the pituitary gland of Xenopus laevis appears to be a complex event, involving various environmental factors (e.g., light and temperature) that act via distinct brain centres and neuronal messengers converging on the melanotrope cells. In the melanotropes, these messages are translated by specific receptors and second messenger systems, in particular via Ca2+ oscillations, controlling main secretory events such as gene transcription, POMC‐precursor translation and processing, posttranslational peptide modifications, and release of a bouquet of POMC‐derived peptides. In conclusion, the Xenopus hypothalamo‐hypophyseal system involved in background adaptation reveals how neuronal plasticity at the molecular, cellular and organismal levels, enable an organism to respond adequately to the continuously changing environmental factors demanding physiological adaptation. Microsc. Res. Tech. 54:188–199, 2001. © 2001 Wiley‐Liss, Inc.
Free‐floating cryostat sections for immunoelectron microscopy: Bridging the gap from light to electron microscopy
Authors: Kan Robert K. , Pleva Christina M. , Backof Daniel R. , Hamilton Tracey A. , Petrali John P.
Published: August 2002

Frozen skin sections are routinely used for light microscopic immunohistochemical study of the skin basement membrane zone for two reasons: some skin basement membrane zone proteins are labile to routine chemical fixation, and skin is not amenable to vibratome sectioning. However, inherent limitations of conventional frozen sections, including compromised morphology and a requirement for glass slide‐mounting, usually limit immunohistochemical study to the light microscopy level. In the present study, we introduce use of unfixed, free‐floating cryostat sections for characterization of immunolocalizations of selected skin basement membrane proteins at both the light and electron microscopy level. The new procedure employs free‐floating cryostat sections that can be processed as routine tissue specimens and can be subjected to a variety of special staining procedures including immunohistochemistry. Especially useful is the ease of progressive processing of the same tissue specimen from light microscopy to electron microscopy. In this regard, the method renders itself useful when results of immunolabeling experiments need to be elucidated quickly at histological and ultrastructural levels as required for diagnostic and accelerated investigative strategies. Microsc. Res. Tech. 54:246–253, 2001. © 2001 Wiley‐Liss, Inc.
Capillary plexus development in the day five to day six chick chorioallantoic membrane is inhibited by cytochalasin D and suramin
Authors: Melkonian Goar , Munoz Nicole , Chung Jeanne , Tong Cathy , Marr Rebecca , Talbot P.
Published: August 2002

The chick chorioallantoic membrane (CAM) is a valuable model for evaluating angiogenesis and vasculogenesis. Our purpose was to characterize the formation of the CAM vasculature, in particular the capillary plexus, between days five and six after fertilization and to examine the mode of action of cytochalasin D and suramin on vascular development during this interval. The CAM increased 20‐fold in size between days five and six, during which time the capillary plexus forms by both migration of mesodermal blood vessels toward the ectoderm and by the formation of new vessels from angioblasts near the ectoderm. Between days five and six, the CAM becomes thinner, and the density of the mesodermal cells decreases. To determine the mode of action of anti‐angiogenic drugs on the day five to day six CAM, various concentrations of cytochalasin D or suramin were added directly to day five CAMs, and their effects were evaluated on day six. Both drugs significantly inhibited CAM growth, altered branching patterns of the major vessels, decreased area of the major vessels, and inhibited the formation of the capillary plexus by inhibiting both vasculogenesis and the migration of mesodermal blood vessels to the ectoderm. Cytochalasin D also inhibited compartmentalization of the plexus. Cytochalasin D and suramin were inhibitory at similar doses. This study provides new information on early CAM development, establishes the mode of action and dose dependency of cytochalasin D and suramin on day five to day six CAMs, and demonstrates that the day five to day six CAM provides a useful assay to examine the effect of anti‐angiogenic drugs on blood vessel development, including capillary plexus formation. J. Exp. Zool. 292:241–254, 2001. © 2002 Wiley‐Liss, Inc.
When bad things happen to good trees*
Authors: Aivaliotis Manuel , Gordon Gary , Graveman William
Published: August 2002

When the edges in a tree or rooted tree fail with a certain fixed probability, the (greedoid) rank may drop. We compute the expected rank as a polynomial in p and as a real number under the assumption of uniform distribution. We obtain several different expressions for this expected rank polynomial for both trees and rooted trees, one of which is especially simple in each case. We also prove two extremal theorems that determine both the largest and smallest values for the expected rank of a (rooted or unrooted) tree, and precisely when these extreme bounds are achieved. We conclude with directions for further study. © 2001 John Wiley & Sons, Inc. J Graph Theory 37: 79–99, 2001
Counting 5‐connected planar triangulations
Authors: Gao Zhicheng J. , Wanless Ian M. , Wormald Nicholas C.
Published: August 2002

Let tn be the number of rooted 5‐connected planar triangulations with 2n faces. We find tn exactly for small n, as well as an asymptotic formula for n → ∞. Our results are found by compositions of lower connectivity maps whose faces are triangles or quadrangles. We also find the asymptotic number of cyclically 5‐edge connected cubic planar graphs. © 2001 John Wiley & Sons, Inc. J Graph Theory 38: 18–35, 2001
Adaptive technology strategies and technical efficiency: Evidence from the Sri Lankan agricultural machinery industry
Authors: Deraniyagala Sonali
Published: August 2002

Recent research has highlighted the importance of technology strategies in influencing the economic performance of firms in developing countries. Attention has focused on two types of strategies: the first involves adopting technologies developed elsewhere without undertaking any modifications and the second involves investing in such technologies but adapting them to suit firm‐specific needs and circumstances. Whilst it has been indicated that the second type of adaptive strategy is likely to lead to higher productivity gains than the first, this hypothesis has not been tested econometrically. Using survey data, this paper undertakes an econometric analysis of the effects of these alternative technology strategies on firm‐level technical efficiency in the agricultural machinery industry in Sri Lanka. Controlling for other possible determinants, it finds that adaptive strategies have a significant positive effect on efficiency in this industry. © 2001 John Wiley & Sons, Ltd.
Mineralized dermal layer of the Brazilian tree‐frog Corythomantis greeningi
Authors: Katchburian E. , Antoniazzi M.M. , Jared C. , Faria F.P. , Souza Santos H. , Freymüller E.
Published: August 2002

Some species of anuran amphibians possess a calcified dermal layer (the Eberth‐Kastschenko layer) located between the “stratum spongiosum” and the “stratum compactum.” This layer consists of calcium phosphate deposits, proteoglycans, and glycosaminoglycans. Although regarded as a protective layer against desiccation, a calcium reservoir, or possibly a remnant of a dermal skeleton present in anuran ancestors, very little is known about its origin, structure, and function. Thus, we studied the structure and composition of the mineralized dermal layer of Corythomantis greeningi, a peculiar hylid from the Brazilian semiarid region (caatinga), using conventional and cryosubstitution methods combined with transmission, scanning, and analytical electron microscopy. Results show that the dermal layer consists of dense, closely juxtaposed, globular structures. Although the electron opacity of the globules was variable, depending on the type of preparation, crystal‐like inclusions were present in all of them, as confirmed by dark field microscopy. Electron probe X‐ray microanalysis showed calcium, phosphorus, and oxygen, and electron diffraction revealed a crystalline structure comparable to that of a hydroxyapatite. J. Morphol. 248:56–63, 2001. © 2001 Wiley‐Liss, Inc.
Histological study of Goniodoris castanea Alder and Hancock, 1845 (Nudibranchia, Doridoidea, Goniodorididae)
Authors: Wägele Heike , Cervera Juan Lucas
Published: August 2002

The major organ systems of Goniodoris castanea were investigated by histological means, with an emphasis on those structures that are difficult to see by dissection. The species is characterized by some peculiar features that are unique or seldom within the Nudibranchia, such as the complete absence of specialized vacuolated cells, the presence of globular salivary glands, the presence of cuticular structures in the proximal intestine, a muscular sphincter around the distal vaginal duct, and the position of the blood gland closer to the pericardium than to the nervous system. Some of these characters are discussed in a phylogenetic context, although a thorough phylogenetic analysis is preliminary, due to lack of knowledge of probably related species. J. Morphol. 250:61–69, 2001. © 2001 Wiley‐Liss, Inc.
Segmentation with gray‐scale connectedness can separate arteries and veins in MRA
Authors: Tizon Xavier , Smedby Örjan
Published: August 2002

Purpose

To describe and present some preliminary results for a novel algorithm for segmentation with gray‐scale connectedness as a means to separate arteries and veins in magnetic resonance angiography (MRA).

Materials and Methods

The proposed algorithm, SeparaSeed, uses the gray‐scale degree of connectedness as a tool to find the zone surrounding each vessel, in order to split the original volume into its different vessel components. In contrast to traditional segmentation methods, no gray‐scale information is lost in the process. The segmentation is performed in one step, resulting in a partition of the initial volume into a chosen number of regions of interest (ROIs). Finally, visualization is achieved by projecting the 3D vessel trees to 2D using the common maximum intensity projection (MIP). The algorithm was tested in two MRA data sets of the vessels of the pelvis acquired after injection of an intravascular contrast agent and in one data set of the vessels of the neck with gadolinium.

Results

In all data sets, a large proportion of the venous signal was removed while preserving that of the arteries, thus improving visualization of the relevant vessels.

Conclusion

Separation of arteries and veins is feasible with the proposed algorithm with a moderate amount of interaction. J. Magn. Reson. Imaging 2002;15:438–445. © 2002 Wiley‐Liss, Inc.
Advances in human cardiac 31P‐MR spectroscopy: SLOOP and clinical applications
Authors: von Kienlin Markus , Beer Meinrad , Greiser Andreas , Hahn Dietbert , Harre Kerstin , Köstler Herbert , Landschütz Wilfried , Pabst Thomas , Sandstede Jörn , Neubauer Stefan
Published: August 2002

Phosphorus magnetic resonance spectroscopy (31P‐MRS) has revealed a lot about the biochemistry of physiological and pathological processes in the heart. Nevertheless, until today, cardiac 31P‐MRS has not had any clinical impact, albeit some pioneering studies demonstrated that 31P‐MRS can indeed provide diagnostic information. In this paper, the development of techniques for human cardiac 31P‐MRS over the past decade is reviewed, and the requirements for a reliable clinical measurement protocol are discussed. Spatial localization with optimal pointspread function (SLOOP) is a new method to achieve spatial localization and absolute quantitation. Its properties are detailed, and preliminary findings in patients with dilated cardiomyopathy or myocardial infarction are presented. J. Magn. Reson. Imaging 2001;13:521–527. © 2001 Wiley‐Liss, Inc.
Laser‐induced interstitial thermotherapy of liver metastases in an interventional 0.5 Tesla MRI system: Technique and first clinical experiences
Authors: Fiedler Volkhard Ulrich , Schwarzmaier Hans‐Joachim , Eickmeyer Frank , Müller Frank Peter , Schoepp Christian , Verreet Patrick Robert
Published: August 2002

Laser‐induced interstitial thermotherapy (LITT) surveyed by magnetic resonance imaging (MRI) has been shown to be effective in various applications. The laser treatment of colorectal liver metastases usually requires a separate device (e.g., ultrasound or CT) to position the laser applicator. In this study, we used an interventional 0.5 T MRI system, allowing both the navigation to the target tissue and on‐line thermometry. Laser irradiation was performed using a near‐infrared laser source combined with a cooled laser light guide. We treated 20 patients exhibiting a total of 58 colorectal liver metastases. Clinically relevant complications did not occur. No residual tumor was observed after laser irradiation in all metastases with a diameter below 2 cm. Metastases with a mean diameter between 2 and 3 cm demonstrated total necrosis in 71%, while in larger tumors this proportion decreased to 46% (diameter, 3–4 cm) and 30% (diameter, >4 cm), respectively. We conclude that LITT, guided by the employed interventional MRI system, is feasible and safe. The results suggest a more aggressive treatment, especially for larger metastases. J. Magn. Reson. Imaging 2001;13:729–737. © 2001 Wiley‐Liss, Inc.
Three‐dimensional adaptive filtering in magnetic resonance angiography
Authors: Westin Carl‐Fredrik , Wigström Lars , Loock Tomas , Sjöqvist Lars , Kikinis Ron , Knutsson Hans
Published: August 2002

In order to enhance 3D image data from magnetic resonance angiography (MRA), a novel method based on the theory of multidimensional adaptive filtering has been developed. The purpose of the technique is to suppress image noise while enhancing important structures. The method is based on local structure estimation using six 3D orientation selective filters, followed by an adaptive filtering step controlled by the local structure information. The complete filtering procedure requires approximately 3 minutes of computational time on a standard workstation for a 256 × 256 × 64 data set. The method has been evaluated using a mathematical vessel model and in vivo MRA data (both phase contrast and time of flight (TOF)). 3D adaptive filtering results in a better delineation of small blood vessels and efficiently reduces the high‐frequency noise. Depending on the data acquisition and the original data type, contrast‐to‐noise ratio (CNR) improvements of up to 179% (8.9 dB) were observed. 3D adaptive filtering may provide an alternative to prolonging the scan time or using contrast agents in MRA when the CNR is low. J. Magn. Reson. Imaging 2001;14:63–71. © 2001 Wiley‐Liss, Inc.
Quadrupole time‐of‐flight versus triple‐quadrupole mass spectrometry for the determination of phosphopeptides by precursor ion scanning
Authors: Steen Hanno , Küster Bernhard , Mann Matthias
Published: August 2002

An API 3000 triple‐quadrupole instrument and a QSTAR Pulsar quadrupole time‐of‐flight (TOF) mass spectrometer were compared for the determination of phosphopeptides by precursor ion scanning in both the positive and negative nanoelectrospray ionization modes. The limits of detection for synthetic phosphopeptides were similar (500 amol µl−1) for both types of instruments when monitoring precursors of −79 Da (PO3−). However, the quadrupole TOF system was approximately fivefold more sensitive (1 fmol µl−1) than the triple‐quadrupole instrument (5 fmol µl−1) when monitoring precursors of 216 Da (immonium ion of phosphotyrosine). The recently introduced Q2‐pulsing function, which enhances the transmission of fragment ions of a selected m/z window from the collision cell into the TOF part, improved the sensitivity of precursor ion scans on a quadrupole TOF instrument. The selectivity of precursor ion scans is much better on quadrupole TOF systems than on triple quadrupoles because the high resolving power of the reflectron‐TOF mass analyzer permits high‐accuracy fragment ion selection at no expense of sensitivity. This minimizes interferences from other peptide fragment ions (a‐, b‐, and y‐ type) of the same nominal mass but with sufficient differences in their exact masses. As a result, the characteristic immonium ion of phosphotyrosine at m/z 216.043 can be utilized for the selective detection of tyrosine phosphorylated peptides. Our data suggest that, in addition to their superior performance for peptide sequencing, quadrupole TOF instruments also offer a very viable alternative to triple quadrupoles for precursor ion scanning, thus combining high sensitivity and selectivity for both MS and MS/MS experiments in one instrument. Copyright © 2001 John Wiley & Sons, Ltd.
Characterization by matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry of the major photoproducts of temoporfin (m‐THPC) and bacteriochlorin (m‐THPBC)
Authors: Angotti Marc , Maunit Benoît , Muller Jean‐François , Bezdetnaya Lina , Guillemin François
Published: August 2002

The photobleaching of 5,10,15,20‐tetrakis(m‐hydroxyphenyl)chlorin (temoporfin, m‐THPC) and 5,10,15,20‐tetrakis(m‐hydroxyphenyl)bacteriochlorin (bacteriochlorin, m‐THPBC) was studied in ethanol–water (1 : 99, v/v) and in physiological medium (phosphate‐buffered saline, PBS) with or without fetal calf serum (FCS). m‐THPC solution was irradiated with the laser radiation of 650 nm, whereas m‐THPBC solution underwent two consecutive irradiations at 532 and 650 nm. The photoproducts were characterized by UV–visible absorption spectrophotometry and by matrix‐assisted laser desorption/ionization (MALDI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). Independent of the solvent used, the phototransformation of either photosensitizer yielded the formation of 5,10,15,20‐tetrakis (m‐hydroxyphenyl)porphyrin (m‐THPP) through a major dehydrogenation process. Copyright © 2001 John Wiley & Sons, Ltd.
Identification and characterization by high‐performance liquid chromatography/electrospray ionization mass spectrometry of a new variant hemoglobin, Mataro [β134(H12) Val > Ala]
Authors: Motos Gallardo A. , Hernández J. A. , Hernández J. M. , Rovira J. M. , Fluvià L. , Bosch A. , Pastor M. C.
Published: August 2002

This work illustrates the practical use of combined microbore reversed‐phase high‐performance liquid chromatography (RP‐HPLC) with electrospray ionization mass spectrometry (ESI‐MS) in protein identification. The approach consisted of the detection of the abnormal β‐globin chain by ESI‐MS analysis of mixtures of intact globins, which simultaneously provided their molecular masses. Separation of the polypeptide globin chains was carried out using microbore C4 RP‐HPLC on‐line with ESI‐MS. Direct peptide‐mapping ESI‐MS without previous chromatographic separation was performed in order to identify tryptic peptides from whole blood. For the sequence confirmation of the abnormal peptide containing the mutation point, C18 RP‐HPLC tryptic separation of the globin mixture on‐line with collision‐induced dissociation (CID) fragmentation was done. The y series ions allowed the identification of the hemoglobin (Hb) variant as [β134(H12) Val > Ala]. This new Hb was named Hb Mataró, after the city where it was detected. Copyright © 2001 John Wiley & Sons, Ltd.
Identification of glucuronide conjugates of ketobemidone and its phase I metabolites in human urine utilizing accurate mass and tandem time‐of‐flight mass spectrometry
Authors: Sundström Ingela , Hedeland Mikael , Bondesson Ulf , Andrén Per E.
Published: August 2002

The glucuronide conjugates of ketobemidone, norketobemidone and hydroxymethoxyketobemidone were identified in human urine post‐intravenous administration of Ketogan Novum. The human urine was extracted on a mixed‐mode solid‐phase micro‐column before analysis with liquid chromatography/electrospray ionization time‐of‐flight mass spectrometry (LC/ESI‐TOF‐MS) and tandem MS (MS/MS). Accurate mass and collision‐induced dissociation product ion spectra were used for identification of the glucuronide conjugates. Two different TOF mass spectrometers were used and the accurate mass measurements were performed on three separate days with each instrument. The accuracy of the mass measurements was better than 2.1 ppm for two out of three conjugates and the inter‐day relative standard deviation was within ±0.00049%. The MS/MS fragmentation patterns of the conjugates were in accordance with those of the synthetic aglycones and included peaks originating from the [M + H]+ ion of the respective aglycone. Copyright © 2002 John Wiley & Sons, Ltd.
Monitoring of in vitro deamidation of gliadin peptic fragment by mass spectrometry may reflect one of the molecular mechanisms taking place in celiac disease development
Authors: Novák Petr , Man Petr , Tučková Ludmila , Tlaskalová‐Hogenová Helena , Bezouška Karel , Havlíček Vladimír
Published: August 2002

Celiac disease, a chronic disorder of the small intestine, is caused by dietary gluten and is characterized by villous atrophy and local inflammation associated with infiltration of B and T lymphocytes and/or macrophages into the intestinal wall. In genetically predisposed individuals, the infiltrating cells are activated by gluten, gliadin and their proteolytic fragments and produce chemokines, cytokines and reactive radicals. The sequence of one of the macrophage‐stimulatory gliadin peptic fragment was determined by mass spectrometry (MS) as VSFQQPQQQYPSSQ. The role of tissue transglutaminase (tTG) in innate immunity stimulation was studied by mass spectrometric monitoring of sequence changes in this active peptide. Two sites of glutamine deamidation in this peptide were localized by high‐resolution scanning in MS/MS mode in an ion trap. A single deamidation in the parent peptide led to the complete loss of its stimulatory effect on macrophages. Copyright © 2002 John Wiley & Sons, Ltd.
Protein identification with Teflon as matrix‐assisted laser desorption/ionization sample support
Authors: Yuan Xianglin , Desiderio Dominic M.
Published: August 2002

Protein identification is a critical step in proteomics, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) plays an important role in that identification. Polytetrafluoroethylene (Teflon) was tested as a new MALDI sample support to improve protein identification. The tryptic peptides obtained from a model protein were bound to the surface of a modified MALDI sample holder via the hydrophobic interactions that occur between the Teflon surface and the peptide ion‐pairs, and the affinity of α‐cyano‐4‐hydroxycinnamic acid for the peptides. During that surface‐binding step, the peptide mixture was also desalted and concentrated. A greater number of matched peptides and a larger sequence coverage were obtained for the proteins when Teflon was used as the sample support compared with conventional sample preparation methods and a stainless‐steel surface. In addition, the characterization of a small amount of protein was improved with Teflon. Nine silver‐stained protein spots obtained from 2‐D gel of a human cerebrospinal fluid (CSF) proteome were identified by this method. Among the nine protein spots, peptide 6:c3c fragment and procollagen c‐proteinase enhancer were not annotated in any published 2‐D map of human CSF. A Teflon MALDI sample support is a low‐cost, simple, and effective method that can be used to improve the quality of the MALDI mass spectrum of a complex tryptic peptide mixture, and to achieve a higher level of reliability and success in protein identification. Copyright © 2002 John Wiley & Sons, Ltd.
Lack of susceptibility of Chacma baboons (Papio ursinus orientalis) to hepatitis C virus infection
Authors: Sithebe N.P. , Kew M.C. , Mphahlele M.J. , Paterson A.C. , Lecatsas G. , Kramvis A. , de Klerk W.
Published: August 2002

The main reason to ascertain whether baboons are susceptible to infection with hepatitis C virus (HCV) is the need to replace chimpanzees, which are endangered, as an animal model for undertaking research into the biology and host–virus interactions of HCV, and for developing a vaccine against this virus. A second reason is that baboons are a possible source of xenografts for human liver transplantation. We inoculated serum containing HCV into four Chacma baboons and monitored them for 52 weeks for evidence of infection. Serum was tested for antibody to HCV, HCV RNA, and aminotransferase concentrations at 2‐week intervals for 26 weeks and thereafter at 4‐week intervals. Liver tissue was examined at 28 and 52 weeks for histopathological changes and viral RNA, and at 52 weeks for viral particles using electron microscopy. Reverse transcription‐polymerase chain reaction assay was used to detect HCV RNA, and the results were confirmed by Southern hybridization. Serum aminotransferase concentrations remained within the normal range and liver histology was normal during the follow‐up period. Passive transmission of anti‐HCV to the baboons was observed during the first 4 weeks. HCV RNA was not detectable in any serum or liver sample and electron microscopy failed to reveal viral particles in liver tissue. In conclusion, we did not find Chacma baboons to be susceptible to infection with HCV, although we cannot deny that in an immunosuppressed liver transplant recipient, infection of a baboon xenograft might occur. Another animal model for HCV infection must be sought. J. Med. Virol. 66:468–471, 2002. © 2002 Wiley‐Liss, Inc.
Reduced postnatal cerebral glucose metabolism measured by PET after asphyxia in near term fetal lambs
Authors: Thorngren‐Jerneck Kristina , Ley David , Hellström‐Westas Lena , Hernandez‐Andrade Edgar , Lingman Göran , Ohlsson Tomas , Oskarsson Gylfi , Pesonen Erkki , Sandell Anders , Strand Sven‐Erik , Werner Olof , Maršal Karel
Published: August 2002

The effects of fetal asphyxia on cerebral function and development, involve the transition from fetal to neonatal life. Changes in cerebral glucose metabolism may be an early postnatal indicator of fetal asphyxia. The objective is to develop an experimental lamb model involving the transition from fetal to neonatal life and to examine the effect of fetal asphyxia with cerebral hypoxic ischemia on early postnatal cerebral glucose metabolism. Fetal asphyxia was induced by total umbilical cord occlusion in eight near‐term fetal lambs (134–138 days) with the ewe under isoflurane‐opiate anesthesia. The mean occlusion time until cardiac arrest was 14.5 (4.2) min (SD). Lambs were immediately delivered and standardized resuscitation was instituted after 2 min asystole. At 4 hr postnatal age, [18‐F]Fluoro‐2‐deoxy‐glucose (18‐FDG) was injected intravenously in eight asphyxiated lambs and in eight controls. Cerebral glucose metabolism was examined by positron emission tomography (PET). As a result the mean arterial blood pressure, acid‐base values, blood glucose and serum lactate at 4 hr postnatal age did not differ significantly between lambs subjected to umbilical cord occlusion and controls. EEG was abnormal in all lambs subjected to cord occlusion and normal in the controls at 4 hr postnatal age. Global cerebral metabolic rate (CMRgl) as determined by PET was significantly lower in lambs subjected to cord occlusion mean/median (SD) 22.2/19.6 (8.4) μmol/min/100 g) than in controls mean/median (SD) 37.8/35.9 (6.1); P < 0.01). Global CMRgl is significantly reduced in newborn lambs 4 hr after fetal asphyxia induced by umbilical cord occlusion. A reduction in CMRgl is an early indicator of global hypoxic cerebral ischemia. © 2001 Wiley‐Liss, Inc.
Deletion of the C‐terminal domain of the NR2B subunit alters channel properties and synaptic targeting of N‐methyl‐D‐aspartate receptors in nascent neocortical synapses
Authors: Mohrmann Ralf , Köhr Georg , Hatt Hanns , Sprengel Rolf , Gottmann Kurt
Published: August 2002

Channel properties and synaptic targeting of N‐methyl‐D‐aspartate (NMDA) receptors determine their importance in synaptic transmission, long‐term synaptic plasticity, and developmental reorganization of synaptic circuits. To investigate the involvement of the C‐terminal domain of the NR2B subunit in regulating channel properties and synaptic localization, we analyzed gene‐targeted mice expressing C‐terminally truncated NR2B subunits (NR2BΔC/ΔC mice; Sprengel et al. [1998] Cell 92:279–89). Because homozygous NR2BΔC/ΔC mice die perinatally, we studied embryonic neocortical neurons differentiating in culture. At early stages in vitro, neurons predominantly expressed NR1/NR2B receptors, as shown by the NR2B subunit‐specific antagonist ifenprodil. At these nascent synapses, NMDA excitatory postsynaptic currents (EPSCs) in neurons from NR2BΔC/ΔC mice showed a strong‐amplitude reduction to 20% of control, but AMPA EPSCs were unaltered. Analysis of the MK‐801 block of NMDA receptor‐mediated whole‐cell currents revealed a decreased peak open probability of NMDA receptor channels (to about 60%) in neurons from NR2BΔC/ΔC mice, although their single channel conductance was unchanged. To study effects on synaptic targeting, we determined the fraction of synaptically localized NMDA receptors relative to the whole‐cell NMDA receptor population. In neurons from NR2BΔC/ΔC mice, the synaptic NMDA receptor fraction was drastically reduced, suggesting that the C‐terminal domain of the NR2B subunit plays a major role in synaptic targeting of NMDA receptors at nascent synapses. With increasing time in culture, the reduction in NMDA EPSCs in neurons from NR2BΔC/ΔC mice diminished. This is explained by the expression of additional NMDA receptor subtypes containing NR2A subunits at more mature synapses. © 2002 Wiley‐Liss, Inc.
Proteins of peripheral myelin are associated with glycosphingolipid/cholesterol‐enriched membranes
Authors: Hasse B. , Bosse F. , Müller H.W.
Published: August 2002

A characteristic feature of the vertebrate nervous system is the ensheathment of axons by myelin, a multilamellar membrane specialization produced by polarized glial cells. Although the main protein and lipid components of the myelin sheath are well characterized, relatively little is known about the mechanisms of their intracellular distribution to the respective sites of assembly within the myelin sheath. To analyze whether peripheral myelin protein trafficking is mediated by glycosphingolipid/cholesterol‐enriched membranes (GEMs), we studied the association of established myelin proteins, peripheral myelin protein 22 (PMP22), protein zero (P0), plasmolipin, and myelin basic protein (MBP), with these membrane microdomains. To examine the association of the selected peripheral myelin proteins with detergent‐insoluble GEMs, purified myelin from sciatic nerve of adult rat was extracted with Triton X‐100 at 4°C and 37°C and, in additional experiments, was pretreated with the cholesterol chelator methyl‐β‐cyclodextrin. The material was then centrifuged to equilibrium in sucrose gradients, and fractions were analyzed by Western blotting. Here we demonstrate for the first time that PMP22, P0, and plasmolipin prepared from purified peripheral myelin are associated with GEMs. To characterize whether the association of these proteins is a specialized feature of myelinating Schwann cells, we studied the distribution of PMP22, P0, and plasmolipin in transiently transfected HeLa cells. These experiments confirm the specific association of these proteins with GEMs in both neural and nonneural cell types. © 2002 Wiley‐Liss, Inc.
Inhibitory effect of neuropeptide Y on morphine withdrawal is accompanied by reduced c‐fos expression in specific brain regions
Authors: Clausen T.R. , Møller M. , Woldbye D.P.D.
Published: August 2002

Neuropeptide Y (NPY) was previously shown in our laboratory to attenuate behavioral signs of morphine withdrawal. To further characterize the anti‐withdrawal effect of NPY, the present study attempted to identify specific brain regions where NPY inhibits neuronal activity during withdrawal. Morphine dependence was induced in male Wistar rats by two daily subcutaneous injections of morphine at increasing doses, and the withdrawal syndrome was precipitated acutely by intraperitoneal administration of naloxone. Rats were pre‐treated with an intracerebroventricular (icv) injection of NPY (12 nmol) or vehicle 30 min before the naloxone challenge. Withdrawal behavior was quantified using a point scoring technique based on motor‐ and non‐motor‐related signs. Brain areas involved in the attenuation of morphine withdrawal were delineated by radioactive in situ hybridization for the immediate early gene c‐fos, which is a marker for neuronal activity. The present study confirmed the inhibitory effect of NPY on withdrawal behavior. Inhibition of behavioral signs of naloxone‐precipitated morphine withdrawal was accompanied by significantly reduced c‐fos expression in the locus coeruleus, lateral septal nucleus, ventral part of the periaqueductal grey, cingulate and frontal cortices, and septohippocampal nucleus. Our data suggest that neo‐ and allo‐cortical areas as well as specific brainstem nuclei are involved in the anti‐withdrawal effects of NPY. J. Neurosci. Res. 64:410–417, 2001. © 2001 Wiley‐Liss, Inc.
NMDA receptor function in mouse models of Huntington disease
Authors: Cepeda Carlos , Ariano Marjorie A. , Calvert Christopher R. , Flores‐Hernández Jorge , Chandler Scott H. , Leavitt Blair R. , Hayden Michael R. , Levine Michael S.
Published: August 2002

Huntington disease (HD) is an autosomal dominant disorder in which degeneration of medium‐sized spiny striatal neurons occurs. The HD gene and the protein it encodes, huntingtin, have been identified but their functions remain unknown. Transgenic mouse models for HD have been developed and we examined responses of medium‐sized striatal neurons recorded in vitro to application of N‐methyl‐D‐aspartate (NMDA) in two of these. The first model (R6/2) expresses exon 1 of the human HD gene with approximately 150 CAG repeats. In the R6/2 an enhancement of currents induced by selective activation of NMDA receptors as well as an enhancement of intracellular Ca2+ flux occurred in both presymptomatic and symptomatic mice. These alterations appeared specific for the NMDA receptor because α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) receptor‐mediated currents were reduced in symptomatic R6/2s. In R6/2 animals there were parallel increases in NMDA‐R1 and decreases in NMDA‐R2A/B subunit proteins as established by immunohistochemistry. The second model (YAC72) contains human genomic DNA spanning the full‐length gene and all its regulatory elements with 72 CAG repeats. The phenotypical expression of the disorder develops more gradually than in the R6/2. In YAC72 mice we found similar but less marked increases in responses of medium‐sized striatal neurons to NMDA. These findings indicate that alterations in NMDA receptor function may predispose striatal neurons to excitotoxic damage, leading to subsequent neuronal degeneration and underscore the functional importance of NMDA receptors in HD. J. Neurosci. Res. 66:525–539, 2001. © 2001 Wiley‐Liss, Inc.
The Pacific–South American modes and their downstream effects
Authors: Mo Kingtse C. , Paegle Julia N.
Published: August 2002

There are two pervasive modes of atmospheric variability in the Southern Hemisphere (SH) that influence circulation and rainfall anomalies over South America. They appear as leading empirical orthogonal functions (EOFs) of 500‐hPa height or 200‐hPa streamfunction anomalies and are found from intraseasonal to decadal time scales. Both patterns exhibit wave 3 hemispheric patterns in mid to high latitudes, and a well‐defined wave train with large amplitude in the Pacific–South American (PSA) sector. Therefore, they are referred to as the PSA modes (PSA1 and PSA2).

PSA1 is related to sea surface temperature anomalies (SSTAs) over the central and eastern Pacific at decadal scales, and it is the response to El Niño–Southern Oscillation (ENSO) in the interannual band. The associated rainfall summer pattern shows rainfall deficits over northeastern Brazil and enhanced rainfall over southeastern South America similar to rainfall anomalies during ENSO. PSA2 is associated with the quasi‐biennial component of ENSO, with a period of 22–28 months and the strongest connections occur during the austral spring. The associated rainfall pattern shows a dipole pattern with anomalies out of phase between the South Atlantic Convergence Zone (SACZ) extending from central South America into the Atlantic and the subtropical plains centred at 35°S.

These two modes are also apparent in tropical intraseasonal oscillations for both summer and winter. Eastward propagation of enhanced convection from the Indian Ocean through the western Pacific to the central Pacific is accompanied by a wave train that appears to originate in the convective regions. The positive PSA1 pattern is associated with enhanced convection over the Pacific from 150°E to the date line. The convection pattern associated with PSA2 is in quadrature with that of PSA1. Both PSA modes are influenced by the Madden Julian Oscillation and influence rainfall over South America. Copyright © 2001 Royal Meteorological Society
Interannual variability of winter precipitation in northern Iberian Peninsula
Authors: Sáenz Jon , Zubillaga Juan , Rodríguez‐Puebla Concepción
Published: August 2002

Observational series of winter precipitation in the eastern part of the Cantabrian coast in the northern Iberian Peninsula are studied. This rather small area shows a clearly different interannual variability to the rest of the Peninsula. Series of winter precipitation for the whole area are defined using principal component (PC) analysis and they reflect the variability that can be attributed to changes in atmospheric circulation around the area. This variability is physically explained on the basis of the structure of baroclinic activity and vertically integrated moisture transports over the area derived from the NCEP/NCAR Reanalysis project. According to them, the leading PC of winter precipitation represents the overall precipitation over the area. Wet phases of this PC are associated to an increase of baroclinic activity leaving the eastern part of the Atlantic storm track and entering the Mediterranean basin. Conversely, dry phases show a strong reduction of baroclinic activity over the region. The second PC is linked to meridional water vapour transports over the area, which are affected by the topography of the region. Copyright © 2001 Royal Meteorological Society
A 40‐year climatological study of relative vorticity distribution over the Mediterranean
Authors: Flocas H.A. , Maheras P. , Karacostas T.S. , Patrikas I. , Anagnostopoulou C.
Published: August 2002

A climatological study of the spatial and temporal distribution of mean relative geostrophic vorticity over the Mediterranean region is examined for a period of 40 years (1958–1997). Two major cyclonic vorticity maxima are found in the Mediterranean at low levels, one covers the Gulf of Genoa and south Italy and the second is located over the southeastern Aegean Sea with different diurnal and seasonal characteristics, controlling cyclone formation. At upper levels, a large scale cyclonic vorticity zone covers the whole Mediterranean region with notably increased values at 300 hPa, being associated with jet stream dynamics, especially in the eastern Mediterranean. The seasonal changes of the horizontal vorticity distribution substantially reduce with height while the diurnal changes become unimportant at upper levels. Furthermore, the investigation of the vertical vorticity structure separately for the main cyclonic centres in the Mediterranean implies the different mechanisms that are responsible for cyclone formation in the western and eastern basin. Copyright © 2001 Royal Meteorological Society
Classification of daily rainfall patterns in a Mediterranean area with extreme intensity levels: the Valencia region
Authors: Peñarrocha D. , Estrela M. J. , Millán M.
Published: August 2002

The objective of this paper is to identify the spatial distribution patterns of heavy rainfall in the Valencia region, Spain. Rainfall in this area reaches one of the highest intensity levels in the Mediterranean, with daily precipitation values above 800 mm. Although high intensities characterize the region's precipitation, there is a zone situated in the south of the Gulf of Valencia that registers exceptionally high daily precipitation intensities.

Our spatial analysis is based on two different perspectives and methods. In the first, we studied the most important torrential rain events in the period 1971–95 and obtained a classification based on the geographical distribution of the daily precipitation maxima. In the second, we applied statistical techniques to classify the distribution patterns of torrential rain by using principal components analysis and cluster analysis. This analysis was conducted for the 1981–90 period. The results of both methodologies are similar and reflect the main characteristics and sub‐types of the spatial distribution of the daily precipitation patterns. These spatial patterns are directly linked to the action of topographic factors in atmospheric situations of humid easterly flows. Copyright © 2002 Royal Meteorological Society.