bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrastructural study of the precursor to fungiform papillae prior to the arrival of sensory nerves in the fetal rat
Authors: Iwasaki Shin‐ichi , Asami Tomoichiro , Kageyama Ikuo 
Published: August 2002

AbstractThe structure of precursors to fungiform papillae without taste buds, prior to the arrival of sensory nerve fibers at the papillae, was examined in the fetal rat on embryonic day 13 (E13) and 16 (E16) by light and transmission electron microscopy in an attempt to clarify the mechanism of morphogenesis of these papillae. At E13, a row of rudiments of fungiform papillae was arranged along both sides of the median sulcus of the lingual dorsal surface, and each row consisted of about 10 rudiments. There was no apparent direct contact between papillae rudiments and sensory nerves at this time. Bilaterally towards the lateral side of the tongue, adjacent to these first rudiments of fungiform papillae, a series of cord‐like invaginations of the dorsal epithelium of the tongue into the underlying connective tissue, representing additional papillary primordia parallel to the first row, was observed. The basal end of each invagination was enlarged as a round bulge, indented at its tip by a mound of fibroblasts protruding into the bulge. At E16 there was still no apparent direct contact between rudiments of fungiform papillae and sensory nerves. Each rudiment apically contained a spherical core of aggregating cells, which consisted of a dense assembly of large, oval cells unlike those in other areas of the lingual dorsal epithelium. The differentiation of these aggregated cells was unclear. The basal lamina was clearly recognizable between the epithelium of the rudiment of fungiform papillae and the underlying connective tissue. Spherical structures, which appeared to be sections of the cord‐like invaginations of the lingual epithelium that appeared on E13, were observed within the connective tissue separated from the dorsal lingual epithelium. Transverse sections of such structures revealed four concentric layers of cells: a central core, an inner shell, an outer shell, and a layer of large cells. Bundles of fibers were arranged in the central core, and the diameters of bundles varied somewhat depending on the depth of the primordia within the connective tissue and their distance from the median sulcus. Ultrastructural features of cells in the outer shell differed significantly in rudiments close to the lingual epithelium as compared to those in deeper areas of connective tissue. Around the outer shell there was a large‐cell layer consisting of one to three layers of radially elongated, oval cells that contained many variously sized, electron‐dense, round granules. Large numbers of fibroblasts formed dense aggregates around each spherical rudiment, and were separated by the basal lamina from the large‐cell epithelial layer. Progressing from deep‐lying levels of the rudiments of the papillae to levels close to the lingual surface epithelium, the central core, inner shell, and outer shell gradually disappeared from the invaginated papillary cords. J. Morphol. 250:225–235, 2001. © 2001 Wiley‐Liss, Inc.
Interaction of a designed interleukin‐10 epitope mimic with an antibody studied by isothermal titration microcalorimetry
Authors: Welfle Karin , Misselwitz Rolf , Sabat Robert , Volk Hans‐Dieter , Schneider‐Mergener Jens , Reineke Ulrich , Welfle Heinz 
Published: August 2002

AbstractThe mechanism of recognition of proteins and peptides by antibodies and the factors determining binding affinity and specificity are mediated by essentially the same features. However, additional effects of the usually unfolded and flexible solution structure of peptide ligands have to be considered. In an earlier study we designed and optimized six peptides (pepI to pepVI) mimicking the discontinuous binding site of interleukin‐10 for the anti‐interleukin‐10 monoclonal antibody (mab) CB/RS/1. Three of them were selected for analysis of their solution conformation by circular dichroism measurements. The peptides differ in the content of α‐helices and in the inducibility of helical secondary structures by trifluoroethanol. These properties, however, do not correlate with the binding affinity. PepVI, a 32‐mer cyclic epitope mimic, has the highest affinity to mab CB/RS/1 identified to date. CD difference spectroscopy suggests an increase of the α‐helix content of pepVI with complex formation. Binding of pepVI to mab CB/RS/1 is characterized by a large negative, favorable binding enthalpy and a smaller unfavorable loss of entropy (ΔH ° = −16.4 kcal·mol−1,TΔS ° = −6.9 kcal·mol−1) resulting in ΔG° = −9.5 kcal·mol−1at 25 °C as determined by isothermal titration calorimetry. Binding of pepVI is enthalpically driven over the entire temperature range studied (10–35 °C). Complex formation is not accompanied by proton uptake or release. A negative heat capacity change ΔCpof −0.354 kcal·mol−1·K−1was determined from the temperature dependence of ΔH °. The selection of protein mimics with the observed thermodynamic properties is promoted by the applied identification and iterative optimization procedure. Copyright © 2001 John Wiley & Sons, Ltd.Abbreviations used:mab CB/RS/1monoclonal anti‐human interleukin‐10 antibodyhIL‐10human interleukin‐10GdnHClguanidine hydrochlorideTFEtrifluoroethanolMOPS3‐morpholinopropane sulfonic acidPIPESpiperazine‐1,4‐bis(2‐ethanesulfonic acid)CDcircular dichroismITCisothermal titration calorimetry.
MR imaging of diffuse adenomyosis changes after GnRH analog therapy
Authors: Imaoka Izumi , Ascher Susan M. , Sugimura Kazuro , Takahashi Kentaro , Li Hong , Cuomo Felicia , Simon James , Arnold Lori L. 
Published: August 2002

AbstractPurposeTo evaluate uterine changes on MRI before and after GnRH analog (GnRHa) treatment in diffuse adenomyosis.Materials and MethodsThirty‐one patients with MRI features suggestive of diffuse adenomyosis received GnRHa for 6 months. Diffuse adenomyosis was sub‐classified as: symmetric (symmetric/ entire widening of the junctional zone [JZ]) and asymmetric (asymmetric/ partial widening of JZ). Pre‐ and post‐high signal intensity (SI) foci and JZ width, and post‐demarcated change (interface of adenomyosis with the myometrium became more discrete with a concomitant decrease in JZ width) were analyzed.ResultsBefore therapy, 15 of 18 asymmetric contained high SI foci compared to none of symmetric. After therapy, JZ width decreased (P < 0.0001). Eight asymmetric and none of symmetric showed demarcated change with resolved high SI foci.ConclusionOur results suggest the use of GnRHa is associated with a decrease of JZ width in adenomyosis. Asymmetric adenomyosis with high SI foci appears to be the most sensitive to hormonal therapy. J. Magn. Reson. Imaging 2002;15:285–290. © 2002 Wiley‐Liss, Inc.
Time evolution of cerebral perfusion and apparent diffusion coefficient measured by magnetic resonance imaging in a porcine stroke model
Authors: Røhl Lisbeth , Sakoh Masaharuh , Simonsen Claus Ziegler , Vestergaard‐Poulsen Peter , Sangill Ryan , Sørensen Jens Cristian , Bjarkam Carsten Reidies , Gyldensted Carsten , Østergaard Leif 
Published: August 2002

AbstractPurposeTo demonstrate the feasibility of sequential diffusion‐weighted (DW) and perfusion‐weighted (PW) magnetic resonance imaging (MRI) of a recently developed porcine stroke model and to evaluate the evolution of cerebral perfusion and the apparent diffusion coefficient (ADC) over time.Materials and MethodsIn five pigs, DW imaging (DWI) and PW imaging (PWI) was carried out for 7 hours after stroke onset, starting 1 hour after middle cerebral artery occlusion (MCAO).ResultsThe DWI lesion volume increased significantly with time, and final DWI lesion volume correlated well with lesion area on histological sections (r = 0.910). T2 changes could be recognized 3 hours after stroke onset. At 1 hour the ADC ratio (ischemic lesion/contralateral side) was reduced to 0.81 in the caudate‐putamen and to 0.87 in the cortex, and the cerebral blood flow ratio was reduced to 0.40 in the caudate‐putamen and 0.51 in the cortex.ConclusionThe level of flow reduction in the caudate‐putamen and the cortex after 1 hour is in good correlation with human thresholds of irreversible and reversible ischemic damage, and accordingly, this model might be a model for mechanisms of infarct evolution and therapeutic intervention. J. Magn. Reson. Imaging 2002;15:123–129. © 2002 Wiley‐Liss, Inc.
Coronary artery imaging using contrast‐enhanced 3D segmented EPI
Authors: Deshpande Vibhas S. , Wielopolski Piotr A. , Shea Steven M. , Carr James , Zheng Jie , Li Debiao 
Published: August 2002

AbstractThe purpose of the work was to evaluate the effectiveness of extracellular contrast media in improving MR coronary angiography using breath‐hold segmented echo‐planar imaging (SEPI). Two protocols were designed to optimize the inversion recovery‐prepared contrast‐enhanced SEPI method. In 15 healthy volunteers, significant improvements in signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), vessel sharpness, and length of visualization were observed post‐contrast. The method with two targeted scans to cover the left and right arteries, respectively, following separate 20‐mL contrast injections, was found to yield thinner slices and longer right coronary artery (RCA) visualization than a single scan following a 40‐mL contrast injection without compromising SNR and CNR. In conclusion, extracellular contrast media substantially improves the delineation of coronary arteries with SEPI. J. Magn. Reson. Imaging 2001;13:676–681. © 2001 Wiley‐Liss, Inc.
An efficient chemical shift imaging scheme for magnetic resonance‐guided neurosurgery
Authors: Liu Haiying , Hall Walter A. , Martin Alastair J. , Truwit Charles L. 
Published: August 2002

AbstractAn efficient magnetic resonance spectroscopic imaging (MRSI) or chemical shift imaging (CSI) technique based on multiple spin echoes (MSE) has been implemented, validated, and used in both phantom and in vivo MR‐guided neurosurgical applications. The key concept of the method is to employ MSE to significantly speed up the data collection rate for mapping hydrogen‐containing metabolites. Using an echo train length (ETL) of three per excitation to simultaneously fill three consecutive k‐space areas, the total scan time for a spectroscopic image matrix size of 32 × 32 has been shortened to approximately 11 minutes. An interecho spacing time of 273 msec was used to null the phase anomalies of lactate double peaks due to the J‐coupling. This allowed a sufficient long data sampling time to achieve 4 Hz spectral resolution. Performing CSI intraopertively during an MR‐guided neurosurgical procedure was shown to be feasible at 1.5 T. More importantly, it was shown that more relevant information can be obtained regarding neurochemistry about a targeted lesion, in addition to conventional MR morphological imaging noninvasively. In 25 MR‐guided neurosurgical cases, the alleviated choline signal has been found to be consistent with the existence of rapid tumor cell proliferation in the corresponding area. The actual neurobiopsy guided by the spectroscopic imaging method demonstrated that it could provide valuable information in specifying the optimal site in a biopsy procedure, especially in the case involving a nonenhancing tumor. The multiecho scheme has made the CSI technique efficient enough to be routinely used in MR‐guided surgical procedures at 1.5 T and also allows the possibility of taking full advantage of MRI capability. J. Magn. Reson. Imaging 2001;14:1–7. © 2001 Wiley‐Liss, Inc.
Osteodensitometry of human heel bones by MR spin‐echo imaging: Comparison with MR gradient‐echo imaging and quantitative computed tomography
Authors: Machann Jürgen , Raible Armin , Schnatterbeck Peter , Lutz Otto , Claussen Claus D. , Schick Fritz 
Published: August 2002

AbstractThe aim of the study was to investigate whether quantitative magnetic resonance (MR) fast spin‐echo (FSE) imaging with moderate spatial resolution enables osteodensitometry in peripheral yellow bone marrow. Signal intensities in T1‐weighted FSE images from yellow bone marrow indicate the amount of adipose tissue per volume. The signal intensity in marrow regions with spongy bone was assessed and compared to signal intensity of pure fatty marrow (100%). Heel bones of 30 patients with suspected osteoporosis were analyzed and the FSE images were compared with results from parallel MR gradient‐echo (GE) imaging and quantitative computed tomography (QCT) examinations. High correlation was found between FSE imaging and QCT [r = 0.91 in the dorsal region of interest (ROI); r = 0.86 in ventral ROI]. Linear correlation coefficients between GE imaging and QCT were slightly lower in the dorsal part (r = –0.86) and considerably lower in the ventral part (r = –0.68). Correlation between the two MR techniques amounted to r = –0.72/–0.61 (dorsal/ventral). The high correlation between FSE imaging and bone mineral density (BMD) allows possible clinical applications of FSE imaging for diagnosis of osteoporosis. Further improvements of the accuracy using reference phantoms might be possible. J. Magn. Reson. Imaging 2001;14:147–155. © 2001 Wiley‐Liss, Inc.
Determination of saccharides in fruit juices by capillary electrophoresis and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Žídková Jitka , Chmelík Josef 
Published: August 2002

AbstractA fast method for the detection of cheap sweeteners is presented. Detecting the adulteration of foods rich in carbohydrates is complicated by the presence of variety of commercial sweeteners that are designed to match exactly the major carbohydrate profiles of these foods. Electrophoretic and mass spectrometric assays for the determination of fruit juice authenticity were developed. Capillary zone electrophoresis with indirect detection was employed to detect adulteration of juices demonstrated by the ratio of the concentrations of major low molecular mass saccharides (glucose, fructose and sucrose). Traces of oligosaccharides, which are not present in the sugar profiles of citrus fruits but are present in inexpensive sweeteners, were evaluated as the other group of target compounds. The fast determination of oligomeric starch hydrolysates in a complex matrix was tested by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and applied to orange juice. MALDI‐TOFMS was shown to be a suitable method for the identification of adulteration of fruit juices by starch hydrolysates. The effects of the presence of salts and low molecular mass saccharides on the detection of oligosaccharides by MALDI‐TOFMS were studied. Low molecular mass saccharides and organic acids decrease the detectability of oligosaccharides by MALDI‐TOFMS, but the concentration of maltooligosaccharides present in juices sweetened with starch hydrolysates is high enough to be detected with good sensitivity. Copyright © 2001 John Wiley & Sons, Ltd.
Investigation of different combinations of derivatization, separation methods and electrospray ionization mass spectrometry for standard oligosaccharides and glycans from ovalbumin
Authors: Saba Julian A. , Shen Xiaodong , Jamieson James C. , Perreault Hélène 
Published: August 2002

AbstractDerivatization procedures using 1‐phenyl‐3‐methyl‐5‐pyrazolone (PMP) and 2‐aminonaphthalene trisulfone (ANTS) were selected among a number of well known methods for labelling carbohydrates. PMP derivatives were selected owing to our laboratory's previous high‐performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI‐MS) experience with these, whereas the ANTS‐labelled compounds were prepared for fluorophore‐assisted carbohydrate electrophoresis (FACE) separation. ANTS‐oligosaccharide standards were characterized to study their ionization patterns. Reversed‐phase and normal‐phase HPLC systems were coupled on‐line with ESI‐MS. Each necessitated its own mobile phase system which, in turn, imposed some important changes in the ionization conditions used and/or on the ionization patterns and spectra obtained. Following characterization of the intact glycoprotein ovalbumin with ESI‐MS, its glycans were detached using the enzyme PNGase‐F. The glycans were subjected to PMP and ANTS derivatization. It was very difficult to separate ANTS derivatives by reversed‐phase HPLC owing to lack of retention, and normal‐phase HPLC offered reasonable retention with limited separation. PMP compounds overall yielded better normal‐ and reversed‐phase separations and improved sensitivity over the ANTS‐labelled sugars, for which negative mode ESI had to be used. The combination of ESI of intact ovalbumin and ESI of PMP‐glycans gave rise to the detection of over 20 different glycoforms, excluding the possible presence of structural isomers for each sugar composition detected. Copyright © 2001 John Wiley & Sons, Ltd.
Regiospecific analysis of neutral ether lipids by liquid chromatography/electrospray ionization/single quadrupole mass spectrometry: validation with synthetic compounds
Authors: Hartvigsen Karsten , Ravandi Amir , Bukhave Klaus , Hølmer Gunhild , Kuksis Arnis 
Published: August 2002

AbstractA reversed‐phase high‐performance liquid chromatography (HPLC) method with on‐line electrospray ionization/collision‐induced dissociation/mass spectrometry (ESI/CID/MS) is presented for the regiospecific analysis of synthetic reference compounds of neutral ether lipids. The reference compounds were characterized by chromatographic retention times, full mass spectra, and fragmentation patterns as an aid to clarify the regiospecificity of ether lipids from natural sources. The results clearly show that single quadrupole mass spectroscopic analysis may elucidate the regiospecific structure of neutral ether lipids. Ether lipid reference compounds were characterized by five to six major ions in the positive ion mode. The 1‐O‐alkyl‐sn‐glycerols were analyzed as the diacetoyl derivative, and showed the [M − acetoyl]+ ion as an important diagnostic ion. The diagnostic ions of directly analyzed 1‐O‐alkyl‐2‐acyl‐sn‐glycerols and 1‐O‐alkyl‐3‐acyl‐sn‐glycerols were the [M − alkyl]+, [M + H − H2O]+ and [M + H]+ ions. Regiospecific characterization of the fatty acid position was evident from the relative ion intensities, as the sn‐2 species had relatively high [M + H]+ ion intensities compared with [M + H − H2O]+, whereas the reverse situation characterized the sn‐3 species. Furthermore, corresponding sn‐2 and sn‐3 species were separated by the chromatographic system. However, loss of water was promoted as fatty acid unsaturation was raised, which may complicate interpretation of the mass spectra. The diagnostic ions of directly analyzed 1‐O‐alkyl‐2,3‐diacyl‐sn‐glycerols were the [M − alkyl]+, [M − sn‐2‐acyl]+ and [M − sn‐3‐acyl]+ ions. Regiospecific characterization of the fatty acid identity and position was evident from the relative ion intensities, as fragmentation of the sn‐2 fatty acids was preferred to the sn‐3 fatty acids; however, loss of fatty acids was also promoted by higher degrees of unsaturation. Therefore, both structural and positional effects of the fatty acids affect the spectra of the neutral ether lipids. Fragmentation patterns and optimal capillary exit voltages are suggested for each neutral ether lipid class. The present study demonstrates that reversed‐phase HPLC and positive ion ESI/CID/MS provide direct and unambiguous information about the configuration and identity of molecular species in neutral 1‐O‐alkyl‐sn‐glycerol classes. Copyright © 2001 John Wiley & Sons, Ltd.
Characterizing closely spaced, complex disulfide bond patterns in peptides and proteins by liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: Yen Ten‐Yang , Yan Hui , Macher Bruce A. 
Published: August 2002

AbstractIdentifying the Cys residues involved in disulfide linkages of peptides and proteins that contain complex disulfide bond patterns is a significant analytical challenge. This is especially true when the Cys residues involved in the disulfide bonds are closely spaced in the primary sequence. Peptides and proteins that contain free Cys residues located near disulfide bonds present the additional problem of disulfide shuffling via the thiol–disulfide exchange reaction. In this paper, we report a convenient method to identify complex disulfide patterns in peptides and proteins using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) in combination with partial reduction by tris(2‐carboxyethyl)phosphine (TCEP). The method was validated using well‐characterized peptides and proteins including endothelin, insulin, α‐conotoxin SI and immunoglobulin G (IgG2a, mouse). Peptide or protein digests were treated with TCEP in the presence of an alkylation reagent, maleimide‐biotin (M‐biotin) orN‐ethylmaleimide (NEM), followed by complete reduction with dithiothreitol and alkylation by iodoacetamide (IAM). Subsequently, peptides that contained alkylated Cys were analyzed by capillary LC/ESI‐MS/MS to determine which Cys residues were modified with M‐biotin/NEM or IAM. The presence of the alkylating reagent (M‐biotin or NEM) during TCEP reduction was found to minimize the occurrence of the thiol–disulfide exchange reaction. A critical feature of the method is the stepwise reduction of the disulfide bonds and the orderly, sequential use of specific alkylating reagents. Copyright © 2001 John Wiley & Sons, Ltd.
Optimization of congener‐specific analysis of 40 polybrominated diphenyl ethers by gas chromatography/mass spectrometry
Authors: Eljarrat E. , Lacorte S. , Barceló D. 
Published: August 2002

AbstractThe analysis by gas chromatography coupled with mass spectrometry (GC/MS) of 40 different congeners of polybrominated diphenyl ethers (PBDEs) containing 1–7 bromine atoms is described. Two different MS approaches were used, negative chemical ionization (NCI‐MS) and electron ionization (EI‐MS). Operating parameters such as electron energy and source temperature were optimized in order to obtain the maximum sensitivity in the EI‐MS study. For NCI‐MS analyses, the effects of the moderating gas (methane or ammonia), source temperature and system pressure were studied. The quality parameters of the two approaches tested were compared. NCI‐MS gave detection limits between 30 fg and 1.72 pg, whereas EI‐MS gave detection limits between 0.53 and 32.09 pg. The main advantage of EI‐MS is that it provides better structural information. Moreover, the use of EI‐MS allowed the use of an isotope dilution method for quantification, making the analysis more reliable at trace levels. Copyright © 2001 John Wiley & Sons, Ltd.