bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomechanical scaling of the hominoid mandibular symphysis
Authors: Daegling David J. 
Published: August 2002

AbstractExperimental investigation of mandibular bone strain in cercopithecine primates has established that the mandible is bent in the transverse plane during the power stroke of mastication. Additional comparative work also supports the assumption that the morphology of the mandibular symphysis is functionally linked to the biomechanics of lateral transverse bending, or “wishboning” of the mandibular corpus. There are currently no experimental data to verify that lateral transverse bending constitutes an important loading regime among hominoid primates. There are, however, allometric models from cercopithecoid primates that allow prediction of scaling patterns in hominoid mandibular dimensions that would be consistent with a mechanical environment that includes wishboning as a significant component. This study uses computed tomography (CT) scans to visualize cortical bone distribution in the anterior corpus of a sample of four genera of extant hominoids. From the cortical bone contours, area properties of the mandibular symphysis are calculated, and these variables are subjected to an allometric analysis to detect whether scaling of jaw dimensions are consistent with a wishboning loading regime. Scaling of the hominoid symphysis recalls patterns observed in cercopithecoid monkeys, which lends indirect support for the hypothesis that wishboning is an integral part of the masticatory loading environment in living apes. Inclination of the symphysis, rather than changes in cross‐sectional shape or development of the superior transverse torus, represents a morphological solution for minimizing the potentially harmful effects of wishboning in the jaws of these primates. J. Morphol. 250:12–23, 2001. © 2001 Wiley‐Liss, Inc.
1‐X‐3 motif in inter‐protein recognition: structures, widespreading and possible practical application
Authors: Verevka S. V. , Miroshnychenko O. S. 
Published: August 2002

AbstractSimilarities in the discrete mode and size of contact areas of a wide range of protein complexes allows us to suggest the existence of a limited number of types of inter‐protein interactions. Comparison of structures of bound determinants indicates that the double‐module, 1‐X‐3 type of motif is widespread in recognition processes. Thus, in many cases, the sites of ligand recognition are formed by two significant amino acids and separated by insignificant ones. Typical examples of such motifs are the RGD sequence of some adhesive and haemostatic proteins, the primary sites for plasminogen sorption on the fibrin network, the reactive sites of protein inhibitors of serine proteinases, and the sites for activation of the hydrolysis of protein pro‐forms and receptors. It is assumed that there is widespread double‐module determinants in many inter‐protein interactions. Copyright © 2001 John Wiley & Sons, Ltd.
Temperature differentially affects encounter and docking thermodynamics of antibody–antigen association
Authors: Lipschultz Claudia A. , Yee Anthony , Mohan S. , Li Yili , Smith‐Gill Sandra J. 
Published: August 2002

AbstractUsing BIACORE SPR, we have examined the mechanism of temperature effects on the binding kinetics of two closely related antibody Fabs (H10 and H26) which recognize coincident epitopes on hen egg‐white lysozyme (HEL), and whose association and dissociation kinetics are best described by the two‐step conformational change model which we interpret as molecular encounter and docking. Time‐course series data obtained at a series of six temperatures (6, 10, 15, 25, 30 and 37 °C) showed that temperature differentially affects the rate constants of the encounter and docking steps. Docking is more temperature‐sensitive than the encounter step, and energetically less favorable at higher temperatures. At elevated temperatures, the time required for docking is longer and the apparent increase in off‐rate reflects the greater proportion of the molecules failing to dock and remaining in the less stable encounter state. As a consequence, distribution of free energy change between the encounter and docking steps is altered. At physiological temperature (37 °C) the docking step of the H26 complex is energetically unfavorable and most complexes essentially do not dock. There is a significant decrease in total free energy change of the H26 complex at higher temperatures. Elevated temperature changes the rate‐limiting step of H26–HEL association from the encounter to the docking step, but not that of H10–HEL. Our results indicate that the mechanism by which elevated temperature reduces the affinities of antigen–antibody complexes is to decrease the net docking rate, and/or stability of the docked complex; at higher temperatures, a smaller proportion of the complexes actually anneal to a more stable docked state. This mechanism may have broad applicability to other receptor–ligand complexes. Published in 2002 by John Wiley & Sons, Ltd.
Sodium T2* relaxation times in human heart muscle
Authors: Pabst Thomas , Sandstede Joern , Beer Meinrad , Kenn Werner , Neubauer Stefan , Hahn Dietbert 
Published: August 2002

AbstractPurposeTo determine sodium transverse relaxation (T2*) characteristics for myocardium, blood and cartilage in humans.MethodsT2* measurements were performed using a 3D ECG‐gated spoiled gradient echo sequence. A 1.5 Tesla clinical scanner and a 23Na heart surface coil were used to examine eight healthy volunteers. In biological tissue, the sodium 23 nucleus exhibits a two‐component T2 relaxation due to the spin 3/2 and its quadrupolar nature. The long T2* components of normal myocardium, blood, and cartilage were quantified. For myocardium, the T2* was determined separately for the septum, anterior wall, lateral wall, and posterior wall.ResultsThe long T2* relaxation time components of 13.3 ± 4.3 msec (septum 13.9 ± 3.2 msec, anterior wall 13.8 ± 5.4 msec, lateral wall 11.4 ± 4.1 msec, posterior wall 14.1 ± 3.7 msec), 19.3 ± 3.3 msec, and 10.2 ± 1.6 msec, were significantly different for myocardium, blood, and cartilage, respectively (P < 0.00001, Friedman's ANOVA).ConclusionMeasurement of 23Na T2* relaxation times is feasible for different regions of the human heart muscle, which might be useful for the evaluation of cardiac pathologies. J. Magn. Reson. Imaging 2002;15:215–218. © 2002 Wiley‐Liss, Inc.
Accuracy of segmented MR velocity mapping to measure small vessel pulsatile flow in a phantom simulating cardiac motion
Authors: Arheden Håkan , Saeed Maythem , Törnqvist Erna , Lund Gunnar , Wendland Michael F , Higgins Charles B , Ståhlberg Freddy 
Published: August 2002

AbstractThe purpose of this study was to investigate the accuracy of conventional, segmented, and echo‐shared MR velocity mapping sequences to measure pulsatile flow in small moving vessels using a phantom with simulated cardiac motion. The phantom moved either cyclically in‐plane, through‐plane, in‐ and through‐plane, or was stationary. The mean error in average flow was –2% ± 3% (mean ± SD) for all sequences under all conditions, with or without background correction, as long as the region of interest (ROI) size was equal to the vessel cross‐sectional size. Overestimation of flow as a result of an oversized ROI was less than 20%, and independent of field of view (FOV) and matrix, as long as the offset in angle between the imaging plane and flow direction was less than 10 degrees. Segmented velocity mapping sequences are surprisingly accurate in measuring average flow and render flow profiles in small moving vessels despite the blurring in the images due to vessel motion. J. Magn. Reson. Imaging 2001;13:722–728. © 2001 Wiley‐Liss, Inc.
Determination of famotidine in low‐volume human plasma by normal‐phase liquid chromatography/tandem mass spectrometry
Authors: Zhong Ling , Eisenhandler Roy , Yeh Kuang C. 
Published: August 2002

AbstractA rapid, sensitive and robust assay procedure using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) for the determination of famotidine in human plasma and urine is described. Famotidine and the internal standard were isolated from plasma samples by cation‐exchange solid‐phase extraction with benzenesulfonic acid (SCX) cartridges. The urine assay used direct injection of a diluted urine sample. The chromatographic separation was accomplished by using a BDS Hypersil silica column with a mobile phase of acetonitrile–water containing trifluoroacetic acid. The MS/MS detection of the analytes was set in the positive ionization mode using electrospray ionization for sample introduction. The analyte and internal standard precursor–product ion combinations were monitored in the multiple‐reaction monitoring mode. Assay calibration curves were linear in the concentration range 0.5–500 ng ml−1 and 0.05–50 µg ml−1 in plasma and urine, respectively. For the plasma assay, a 100 µl sample aliquot was subjected to extraction. To perform the urine assay, a 50 µl sample aliquot was used. The intra‐day relative standard deviations at all concentration levels were <10%. The inter‐day consistency was assessed by running quality control samples during each daily run. The limit of quantification was 0.5 ng ml−1 in plasma and 0.05 µg ml−1 in urine. The methods were utilized to support clinical pharmacokinetic studies in infants aged 0–12 months. Copyright © 2001 John Wiley & Sons, Ltd.
Reactions of BBrn+ (n = 0–2) at fluorinated and hydrocarbon self‐assembled monolayer surfaces: observations of chemical selectivity in ion–surface scattering
Authors: Wade Nathan , Shen Jianwei , Koskinen Jere , Cooks R. Graham 
Published: August 2002

AbstractIon–surface reactions involving BBrn+ (n = 0–2) with a fluorinated self‐assembled monolayer (F‐SAM) surface were investigated using a multi‐sector scattering mass spectrometer. Collisions of the B+ ion yield BF2+ at threshold energy with the simpler product ion BF+· appearing at higher collision energies and remaining of lower abundance than BF2+ at all energies examined. In addition, the reactively sputtered ion CF+ accompanies the formation of BF2+ at low collision energies. These results stand in contrast with previous data on the ion–surface reactions of atomic ions with the F‐SAM surface in that the threshold and most abundant reaction products in those cases involved the abstraction of a single fluorine atom. Gas‐phase enthalpy data are consistent with BF2+ being the thermodynamically favored product. The fact that the abundance of BF2+ is relatively low and relatively insensitive to changes in collision energy suggests that this reaction proceeds through an entropically demanding intermediate at the vacuum–surface interface, one which involves interaction of the B+ ion simultaneously with two fluorine atoms. By contrast with the reaction of B+, the odd‐electron species BBr+· reacts with the F‐SAM surface to yield an abundant single‐fluorine abstraction product, BBrF+. Corresponding gas‐phase ion–molecule experiments involving B+ and BBr+· with C6F14 also yield the products BF+· and BF2+, but only in extremely low abundances and with no preference for double fluorine abstraction. Ion–surface reactions were also investigated for BBrn+ (n = 0–2) with a hydrocarbon self‐assembled monolayer (H‐SAM) surface. Reaction of the B+ ion and dissociative reactions of BBr+· result in the formation of BH2+, while the thermodynamically less favorable product BH+· is not observed. Collisions of BBr2+ with the H‐SAM surface yield the dissociative ion–surface reaction products, BBrH+ and BBrCH3+. Substitution of bromine atoms on the projectile by hydrogen or alkyl radicals suggests that Br atoms may be transferred to the surface in a Br‐for‐H or Br‐for‐CH3 transfer reaction in an analogous fashion to known transhalogenation reactions at the F‐SAM surface. The results for the H‐SAM surface stand in contrast to those for the F‐SAM surface in that enhanced neutralization of the primary ions gives secondary ion signals one to two orders of magnitude smaller than those obtained when using the F‐SAM surface, consistent with the relative ionization energies of the two materials. Copyright © 2001 John Wiley & Sons, Ltd.
Lipid A structure of Pseudoalteromonas haloplanktis TAC 125: use of electrospray ionization tandem mass spectrometry for the determination of fatty acid distribution
Authors: Corsaro Maria Michela , Piaz Fabrizio Dal , Lanzetta Rosa , Parrilli Michelangelo 
Published: August 2002

AbstractThe use of electrospray Ionization (ESI) tandem mass spectrometry (MS/MS) for the structural determination of the lipid A components of the psychrophilic bacterium Pseudoalteromonas haloplanktis TAC 125 is reported. The lipid A contains the classical bisphosphorylated β‐(1′ → 6)‐linked D‐glucosamine disaccharide with 3‐hydroxydodecanoyl residues (12 : 0 (3‐OH)) linked both as esters and amides to 2′, 3′ (distal glucosamine) and 2, 3 positions (proximal glucosamine) of the sugar backbone. The hydroxyl of 12 : 0 (3‐OH) fatty acid linked at the 3′ position is esterified by a dodecanoyl residue (12 : 0). In addition to the pentaacyl component, a minor tetraacyl lipid A, lacking the acyl residue at position 3, was also found in the lipid A fraction. The advantage of this MS technique for the investigation of the intra‐ring fragmentation, which is useful for the determination of fatty acyl residue distribution on each glucosamine unit, is emphasized. Copyright © 2002 John Wiley & Sons, Ltd.
Influence of the dynamics of the hypervariable region 1 of hepatitis C virus (HCV) on the histological severity of HCV recurrence after liver transplantation
Authors: Sánchez‐Fueyo Alberto , Giménez‐Barcons Mireia , Puig‐Basagoiti Francesc , Rimola Antoni , María Sánchez‐Tapias Jose , Sáiz Juan Carlos , Rodés Juan 
Published: August 2002

AbstractRecurrence of hepatitis C virus (HCV) infection after liver transplantation is almost universal and usually leads to chronic hepatitis with different degrees of severity. The pathogenic mechanisms underlying the variable outcome of HCV infection recurrence are not well defined, but recent data suggest that the dynamics of HCV quasispecies may be involved. HCV quasispecies evolution was traced by longitudinal single strand conformation polymorphism, direct sequencing, and cloning analyses of pre‐ and post‐transplant HCV‐1b isolates from patients with histologically severe (seven cases) or mild or moderate (nine cases) HCV infection recurrence. Differences between the two groups of patients that concerned the level of viremia or the degree of HCV quasispecies complexity and diversity were not observed at any of the three time points analyzed. However, emergence of nucleotide and amino acid changes during the 12 months follow‐up was significantly more frequent in patients with mild or moderate than in those with severe HCV infection recurrence. The ratio of non‐synonymous to synonymous nucleotide substitutions 12 months after transplantation was also greater in the former, suggesting that the HVR1 of HCV is under stronger selective pressure in these subjects. These findings suggest that the degree of amino acid diversification in the HVR1 of HCV, which probably reflects the strength of immune pressure on HCV, is inversely related to the histological severity of HCV infection recurrence. J. Med. Virol. 65:266–275, 2001. © 2001 Wiley‐Liss, Inc.
Sensitive detection and differentiation of Sapporo virus, a member of the family Caliciviridae, by standard and booster nested polymerase chain reaction
Authors: Honma Shinjiro , Nakata Shuji , Sakai Yoshiyuki , Tatsumi Masatoshi , Numata‐Kinoshita Kazuko , Chiba Shunzo 
Published: August 2002

AbstractNorwalk virus and Sapporo virus (SV) were approved as type species of the genus Norwalk‐like viruses and the genus Sapporo‐like viruses, respectively, in the family Caliciviridae. Nested polymerase chain reaction (PCR), using newly designed primers in the RNA‐dependent RNA polymerase region, was developed to detect and differentiate viruses in the three genetic groups of SV based on the relative size of the PCR products obtained. In addition, a booster nested PCR that performs nested PCR in a single tube was introduced to reduce the chance of contamination during the procedure of standard nested PCR. The specificity of the newly developed PCR was confirmed by testing 77 stool specimens and 16 tissue culture fluids derived from growth of unrelated viruses. The sensitivity of the nested PCR was compared with the conventional PCR using Sapp35/Sapp36 primer pair by testing the three cDNA clones obtained from viruses in the SV/SV82, the SV/London92, and the SV/Parkville virus, respectively. This assay can detect SV in a more sensitive way than the conventional PCR and Southern hybridization. Sensitive and suitable methods to detect and differentiate SV are required to obtain accurate epidemiological data on these viruses and the standard and booster nested PCR should be a very useful tool for this purpose. J. Med. Virol. 65:413–417, 2001. © 2001 Wiley‐Liss, Inc.
Failure of stavudine‐lamivudine combination therapy in antiretroviral‐naive patients with AZT‐Like HIV‐1 resistance mutations
Authors: Sarmati Loredana , Nicastri Emanuele , Parisi Saverio Giuseppe , D'Ettorre Gabriella , Narciso Pasquale , Mancino Giorgio , Gallo Isa , Abbadessa Vincenzo , Dalle Nogare Ernesto Renato , Traina Cino , Vullo Vincenzo , Andreoni Massimo 
Published: August 2002

AbstractTo analyze the clinical relevance of AZT resistance mutations in AZT‐naive patients, 56 HIV‐1 seropositive patients treated for 18 months with stavudine/lamivudine (27 patients) or AZT/lamivudine (29 patients) were studied. AZT‐like resistance mutations were found in 13 out of 29 (44%) patients treated with AZT/lamivudine and in 11 out of 27 (40%) patients treated with stavudine/lamivudine. No stavudine or multi‐drug resistance mutations were detected. After 26 months of treatment more than 60% of patients showed a virological failure. Among 10 patients failing treatment with stavudine/lamivudine, 9 had AZT‐like resistance mutations. The phenotypic test, performed on HIV‐1 strains isolated from six of these nine patients, showed a resistance to AZT in five isolates and to stavudine in two isolates. The genotypic pattern of the latter two isolates showed the combined mutations M184V plus R211K and L214F. AZT‐like resistance mutations in AZT‐naive patients seem to correlate with a virological failure during long‐term stavudine therapy. J. Med. Virol. 65:631–636, 2001. © 2001 Wiley‐Liss, Inc.
Genetic variability of the V1 and V2 env domains of SIVcpz‐ant and neutralization pattern of plasma viruses in a chimpanzee infected naturally
Authors: Ondoa Pascale , Davis David , Willems Betty , Heyndrickx Leo , Kestens Luc , van der Berg Ingrid , Coppens Sandra , Janssens Wouter , Heeney Jonathan , van der Groen Guido 
Published: August 2002

AbstractSpecific neutralizing epitope changes have been observed in a chimpanzee infected naturally with SIVcpz, which differ from HIV‐1 infecting humans. To characterize further these changes, a longitudinal study of env genomic sequence variation of SIVcpz‐ant isolates was undertaken in this animal. The V1 and V2 regions of the env were determined to arise from specific recombination events. To determine whether recombination of the V1 and V2 domains was possibly associated with the emergence of neutralization escape viruses, envelope sequences and gene length polymorphisms from PBMC and plasma viral variants were studied over a 7‐year period. PBMCs and plasma‐associated infectious virus titers as well as plasma RNA viral loads were monitored longitudinally. The first 5 viruses isolated from the plasma were found to be neutralization escape variants. Sequence analysis of their V1 and the V2 regions indicated that a 20 amino acid stretch of the V1 region had undergone recombination and was also associated with the emergence of isolates eliciting strong neutralization responses. These findings support the hypothesis that recombination of the V1 and V2 regions of the envelope play a role in neutralization escape of SIVcpz in chimpanzees infected naturally. Furthermore, the data confirm that the neutralizing antibody response plays an important role in the decline of plasma infectious virus titers in HIV‐1 related SIVcpz nonpathogenic infection. J. Med. Virol. 65:765–776, 2001. © 2001 Wiley‐Liss, Inc.
TLM for diffusion: the artefact of the standard initial conditions and its elimination within an abstract TLM suite
Authors: Enders Peter , Cogan Donard de 
Published: August 2002

AbstractWe demonstrate both analytically and numerically, that for the TLM algorithm for numerically solving the diffusion equation the standard initial conditions for the incident voltage pulses in terms of the initial concentration (or temperature) distribution introduce a significant numerical error. We discover the origin of this error and present an alternative prescription for computing the node voltages at the first time step which removes this artefact and exhibits distinctly improved numerical accuracy. For this, we introduce the term abstract TLM suite (ATS). An ATS is a numerical scheme which formally parallels a TLM scheme, but the scattering coefficients, ρ and τ, may assume values outside the interval [−1, 1] or may not correspond to the values of a real TLM network. Copyright © 2001 John Wiley & Sons, Ltd.
Finding new candidate genes for learning and memory
Authors: Leil Tarek A. , Ossadtchi Alex , Cortes James S. , Leahy Richard M. , Smith Desmond J. 
Published: August 2002

AbstractThe genetic mechanisms underlying learning and memory remain mysterious, but many of the genes are likely to be expressed in the hippocampus, a region pivotal to this process. We used a 9,000 gene microarray to examine differences in hippocampal gene expression between two F1 hybrid mouse strains that perform well on the Morris water maze and two inbred strains that perform poorly. This resulted in identification of 27 differentially expressed genes, which could be used to place the F1 hybrid and inbred strains into separate clusters based on singular value decomposition. Most of the genes have unknown function, but those with known functions may provide clues to the molecular mechanisms of learning. Using multiple strains to narrow down the number of candidate genes should be a useful general approach to genome‐wide studies of behavioral and other complex traits. © 2002 Wiley‐Liss, Inc.