bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the internal temperatures of an 8.6 kDa protein cation exposed to a hot dispenser cathode employed in electron capture dissociation mass spectrometry
Authors: Yim Yong‐hyeon , Kim Byungjoo , Ahn Seonghee , So Hun‐Young , Lee Sunyoung , Oh Han Bin 
Published: May 2006

AbstractThe ‘effective’ internal temperature of an 8.6 kDa ubiquitin cation was estimated under electron capture dissociation (ECD) conditions, in which a dispenser cathode electron source was mounted just outside an ion cyclotron resonance (ICR) cell, i.e., axially displaced at a distance less than 1 cm from the rear trap plate of the ICR cell. In this ECD configuration, thermal activation of the molecular ions stored in the ICR cell was anticipated since the heated dispenser cathode (Tcathode surface > 1000°C) emitted a large amount of (both visible and infrared) radiation as well as electrons. An evaluation of the internal temperature of ubiquitin 6+ and 7+ cations was made by comparing our ECD fragmentation patterns with those obtained by McLafferty et al. (J. Am. Chem. Soc. 2002; 124: 6407) as a function of the ion temperature. In McLafferty's configuration, the heating (or thermal activation) effect of their filament source was minimal since the filament was displaced by a distance as far as 70 cm from their ICR cell. A careful comparison reveals that the fragmentation patterns obtained in this work are very similar to those previously measured at T ∼ 125°C. In terms of sequence coverage, our ECD configuration provides better results, and in particular without the aid of any other simultaneous activation method, such as thermal heating, infrared multiphoton irradiation, or collisional activation, except for the visible and infrared radiation from the heated cathode. Copyright © 2006 John Wiley & Sons, Ltd.
Development of a sensitive and rapid liquid chromatography/tandem mass spectrometry method for the determination of apomorphine in canine plasma
Authors: Yang B. , Zhu J. B. , Deng C. H. , Duan G. L. 
Published: May 2006

AbstractA sensitive, rapid and specific quantitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for the determination of apomorphine (APO) in canine plasma. The analytes were prepared using one‐step liquid‐liquid extraction, and analyzed on a Waters Symmetry C18 column interfaced with triple quadrupole tandem mass spectrometer. A mixture of methanol/0.1% formic acid in water (70: 30, v/v) was employed as the isocratic mobile phase. Positive electrospray ionization was utilized as the ionization source. The analyte and clenbuterol (internal standard) were both detected using multiple reaction monitoring (MRM) mode. The limit of detection (LOD) obtained was 0.03 ng/mL. The assay was linear over the concentration range of 0.1–100 ng/mL, and provided good precision (RSD) and good accuracy (RE). The analyte was stable by using antioxidants throughout the whole study. The experimental results show that LC/MS/MS is a rapid and sensitive method to analyze APO in plasma. Finally, the proposed method was successfully applied to a pharmacokinetic study of APO after intranasal administration of 0.5 mg apomorphine to 10 healthy beagle dogs. Copyright © 2006 John Wiley & Sons, Ltd.
Top‐down analysis of basic proteins by microchip capillary electrophoresis mass spectrometry
Authors: Akashi Satoko , Suzuki Koichi , Arai Akihiro , Yamada Naoyuki , Suzuki Ei‐Ichiro , Hirayama Kazuo , Nakamura Shin , Nishimura Yoshifumi 
Published: May 2006

AbstractA system of microchip capillary electrophoresis/electrospray ionization mass spectrometry (µchip‐CE/ESI‐MS) for rapid characterization of proteins has been developed. Capillary electrophoresis (CE) enables rapid analysis of a sample present in very small quantity, such as at femtomole levels, at high resolution. Faster CE/MS analysis is expected by downsizing the normal capillary to the microchip (µchip) capillary. Although rapidity and high resolution are advantages of CE separation, electroosmotic flow (EOF) instability caused by the interaction between proteins and the microchannel surface results in low reproducibility in the analysis of basic proteins under neutral pH conditions. By coating the microchannel surface with a basic polymer, polyE‐323, basic proteins, which have pI values of over 7.5, could be separated and detected by µchip‐CE/MS on quadrupole (Q) and time‐of‐flight (TOF) hybrid instruments. By increasing the cone and collision voltages during the analysis by µchip‐CE/ESI‐MS of a small protein, some product ions, which contain the sequence information, could also be obtained, i.e., ‘top‐down’ analysis of the protein could be accomplished with this µchip‐CE/MS system. To our knowledge, this is the first report of ‘top‐down’ analysis of a protein by µchip‐CE/MS. Since it requires a much shorter time and a smaller sample amount for analysis than the conventional liquid chromatography (LC)/ESI‐MS method, µchip‐CE/MS promises to be suitable for the high‐throughput characterization of proteins. Copyright © 2006 John Wiley & Sons, Ltd.
Identification of the aromatase inhibitors anastrozole and exemestane in human urine using liquid chromatography/tandem mass spectrometry
Authors: Mareck Ute , Geyer Hans , Guddat Sven , Haenelt Nadine , Koch Anja , Kohler Maxie , Opfermann Georg , Thevis Mario , Schänzer Wilhelm 
Published: May 2006

AbstractAnastrozole (2,2′‐[5‐(1H‐1,2,4‐triazol‐1‐ylmethyl)‐1.3‐phenylene]bis(2‐methylpropionitrile)) and exemestane (6‐methylenandrostan‐1,4‐diene‐3,17‐dione) are therapeutically used to treat hormone‐sensitive breast cancer in postmenopausal women. For doping purposes they may be used to counteract adverse effects of an extensive abuse of anabolic androgenic steroids (gynaecomastia) and to increase plasma testosterone concentrations. Excretion study urine samples and spot urine samples from women suffering from metastatic breast cancer, being treated with anastrozole or exemestane, were collected and analyzed to develop/optimize a detection system for anastrozole and exemestane to allow the identification of athletes who do not comply with the internationally prohibited use of these cancer drugs. The assay was based on liquid‐liquid extraction after enzymatic hydrolysis following liquid chromatography/tandem mass spectrometry (LC/MS/MS). Anastrozole, exemestane and its main metabolite (17‐dihydroexemestane) were identified in urine by comparison of mass spectra and retention times with respective reference substances. An assay validation for the analysis of anastrozole and exemestane was performed regarding lower limits of detection (anastrozole: 0.02 ng/mL; exemestane: 3.1 ng/mL; dihydroexemestane: 0.5 ng/mL), interday precisions (6.6–11.1%, 4.9–9.1% and 5.6–8.3% for low [10 ng/mL], medium [50 ng/mL] and high [100 ng/mL] concentration) and recoveries (ranged from 85–97%). Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of the in vivo receptor occupancy for the behavioral effects of cannabinoids using a radiolabeled cannabinoid receptor agonist, R‐[125/131I]AM2233
Authors: Dhawan Jasbeer , Deng Hongfeng , Gatley S. John , Makriyannis Alexandros , Akinfeleye Tolulope , Bruneus Magalie , Dimaio Alexis A. , Gifford Andrew N. 
Published: May 2006

AbstractG‐protein coupled receptors exist in both high and low agonist affinity conformations, with tracer levels of agonist radioligands preferentially binding to the former. The goal of the present study was to characterize the in vivo binding of the aminoalkyindole‐based, CB1 receptor agonist,R‐[125/131I]AM2233 ((2‐[125/131I]iodo‐phenyl)‐[1‐(1‐methyl‐piperidin‐2‐yl‐methyl)‐1H‐indol‐3‐yl]‐methanone), and to use this radiotracer to selectively measure the receptor occupancy by the related CB1 receptor agonist, WIN55212‐2, to the agonist‐preferring affinity state of the receptor. In mouse locomotor assays, both WIN55212‐2 and AM2233 (racemic) produced an ∼60% reduction in activity at 1 mg/kg, (i.v.) and completely inhibited activity at 3 mg/kg, confirming their agonist nature. In ex vivo autoradiography, preferential uptake ofR‐[131I]AM2233 was apparent in CB1 receptor‐rich areas, including globus pallidus, substantia nigra, striatum, cerebellum, and hippocampus. Overall brain uptake ofR‐[131I]AM2233 was 1.3% injected activity/g at 5 min in mice. Coinjection of 3 mg/kg (i.v.) SR141716A, a CB1 receptor antagonist, withR‐[125I]AM2233 inhibited the radiotracer binding almost to nonspecific levels in the striatum, globus pallidus, and substantia nigra, although residual binding to a non‐CB1 receptor remained in the hippocampus. In contrast to the effect of SR141716A, coinjection of 10 mg/kg (i.v.) WIN55212‐2, a high dose that produced an immediate and profound immobility and catalepsy in the mice, reduced CB1 receptor‐specific binding ofR‐[125I]AM2233 in CB1 receptor‐rich areas by only 21–43%. These observations suggest that the behavioral effects of CB1 receptor agonists are manifested with a relatively small fraction of the agonist‐preferring affinity state of the receptor occupied. Synapse 60:93–101, 2006. © 2006 Wiley‐Liss, Inc.
Exocytotic release of creatine in rat brain
Authors: Almeida Ligia S. , Salomons Gajja S. , Hogenboom Francois , Jakobs Cornelis , Schoffelmeer Anton N.M. 
Published: May 2006

AbstractThe guanidino compound creatine has been shown to occur throughout the brain affecting energy metabolism and mental performance and to act at central GABAA receptors as a partial agonist. Therefore, we examined the possibility that creatine may in fact represent a neuromodulator that is released in the brain in an action‐potential dependent manner. To that end, we studied the uptake of [3H]creatine and its electrically evoked release from superfused rat brain slices as well as the evoked release of endogenously synthesized creatine. [3H]creatine was accumulated in neocortex slices in a Na+‐dependent manner, consistent with the involvement of the Na+‐dependent SLC6A8 creatine transporter. Most importantly, the electrically evoked release of [3H]creatine from neocortex slices (like that from caudate putamen and hippocampus slices) as well as the evoked release of endogenous (unlabeled) creatine was abolished when Ca2+ was omitted from the superfusion medium or in the presence of theNa+‐channel blocker tetrodotoxin (TTX). Moreover, blockade of K+‐channels by 4‐aminopyridine (4‐AP) strongly enhanced the electrically evoked release of [3H]creatine as well as that of endogenous creatine. These in vitro data indicate that creatine is not only synthesized and taken up by central neurons, but also released in an action‐potential dependent (exocytotic) manner, providing strong evidence for its role as a neuromodulator in the brain. Synapse 60:118–123, 2006. © 2006 Wiley‐Liss, Inc.
Antipsychotic pathway genes with expression altered in opposite direction by antipsychotics and amphetamine
Authors: Ko Françoise , Tallerico Teresa , Seeman Philip 
Published: May 2006

AbstractTo develop a new strategy for identifying possible psychotic‐ or antipsychotic‐related pathway genes, rats were treated with clinical doses of haloperidol and clozapine for 4 days, and the altered expression of genes was compared with the genes altered in expression after amphetamine sensitization. The objective was to identify genes with expression altered in the same direction by haloperidol and clozapine but in the opposite direction in the amphetamine‐sensitized rat striatum. These criteria were met by 21 genes, consisting of 15 genes upregulated by amphetamine, and 6 genes downregulated by amphetamine. Of the 21 genes, 15 are not presently identified, and only 3 genes (cathepsin K, GRK6, and a gene with accession number AI177589) are located in chromosome regions known to be associated with schizophrenia. Synapse 60:141–151, 2006. © 2006 Wiley‐Liss, Inc.
Self‐definition of women experiencing a nontraditional graduate fellowship program
Authors: Buck Gayle A. , Leslie‐Pelecky Diandra L. , Lu Yun , Plano Clark Vicki L. , Creswell John W. 
Published: May 2006

AbstractWomen continue to be underrepresented in the fields of science, technology, engineering, and mathematics (STEM). One factor contributing to this underrepresentation is the graduate school experience. Graduate programs in STEM fields are constructed around assumptions that ignore the reality of women's lives; however, emerging opportunities may lead to experiences that are more compatible for women. One such opportunity is the Graduate Teaching Fellows in K–12 Education (GK–12) Program, which was introduced by the National Science Foundation in 1999. Although this nontraditional graduate program was not designed explicitly for women, it provided an unprecedented context in which to research how changing some of the basic assumptions upon which a graduate school operates may impact women in science. This exploratory case study examines the self‐definition of 8 women graduate students who participated in a GK–12 program at a major research university. The findings from this case study contribute to higher education's understanding of the terrain women graduate students in the STEM areas must navigate as they participate in programs that are thought to be more conducive to their modes of self‐definition while they continue to seek to be successful in the historically Eurocentric, masculine STEM fields. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 852–873, 2006
Normal fetal motility: an overview
Authors: de Vries J. I. P. , Fong B. F. 
Published: May 2006

AbstractAfter 35 years of real‐time two‐dimensional sonography, and now that 4D sonography is within our grasp, this article presents an overview of present‐day knowledge of normal fetal motility. A literature search was carried out on articles from 1970, using the keywords: ‘fetal’, ‘movements’, ‘motility’, ‘movement patterns’, ‘ultrasound’ and ‘sonography’. Inclusion criteria were human studies and use of real‐time sonography. Articles were screened for type of motor assessment procedure, in terms of whether they: specified movements for participating body parts (specific movement pattern, SMP), were qualitative (performance in terms of speed and amplitude), were quantitative, identified behavioral states, stated the duration of observation, and specified gestational age. We noted developmental milestones obtained for each study aim. One of four aims was identified for each article, depending on whether it focused on emergence, development, or continuity after birth of the movement patterns, or on the relationship of various motor aspects to other parameters that evaluate fetal condition, such as blood flow and fetal heart rate. A total of 109 relevant articles was identified, examining 9862 fetuses. Assessment was performed primarily with analysis of SMPs (89%); 52% also included non‐SMPs (NSMPs), 78% included quantification, 24% assessment of quality, and 32% behavioral states. The duration of observation was 1 h or longer in 50% of the studies. The focus in 28 studies was on emergence, in 44 it was on development, in five it was on continuity and in 32 it was on relationship of the movements with other parameters of fetal well‐being. A few milestones identified were determination of the strictly age‐related emergence of SMPs and behavioral states, the highly reproducible quality of SMPs throughout gestation, the age‐related trends in quantified SMPs, the continuity in quality and quantity after birth, and the close relationship between motility and heart‐rate variability, flow parameters, and behavioral states. Periods of longest inactivity recorded before 20 weeks were 13 min; after 30 weeks they were 45 min. Much insight was obtained into the development of motility and its relationship to other parameters from those articles applying comparable assessment procedures. An assessment procedure with well‐defined SMPs, qualitative and quantitative aspects of SMPs and NSMPs, and an observation period dependent on age are advocated for future research. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Sequential triage in the first trimester may enhance advanced ultrasound scanning in population screening for trisomy 21
Authors: Gyselaers W. J. A. , Roets E. R. A. , Van Holsbeke C. D. Y. J. , Vereecken A. J. , Van Herck E. J. H. , Straetmans D. P. L. , Ombelet W. U. A. M. , Nijhuis J. G. 
Published: May 2006

AbstractObjectiveTo design a trisomy 21 screening protocol for sequential triage in the first trimester, and to evaluate whether it reduces the need for advanced ultrasound scanning to such an extent that this could be dealt with by a limited number of well‐trained sonographers only.MethodsScreening results of 31 trisomy 21 affected pregnancies and 16 096 unaffected pregnancies from the first trimester screening program of Algemeen Medisch Laboratorium in Antwerp, Belgium, were used to define high‐risk, intermediate‐risk and low‐risk groups. A serum screening result (age, pregnancy‐associated plasma protein‐A (PAPP‐A) and free beta‐human chorionic gonadotropin (β‐hCG)) of ≥1 : 30 and/or a nuchal translucency thickness (NT) measurement of ≥ 3.5 mm were classified as high risk. A serum screening result of < 1 : 1000 together with an NT of < 3.5 mm were classified as low risk. Other results were considered intermediate risk, for which further advanced ultrasound screening would be indicated. This protocol was then evaluated prospectively in another population of 13 493 first‐trimester pregnancies.ResultsOf the total population, 1.9% was identified as being high risk (14 trisomy 21 pregnancies and 222 unaffected pregnancies; prevalence, 1 : 17), 59.6% was identified as being low risk (three trisomy 21 pregnancies and 9615 unaffected pregnancies; prevalence, 1 : 3206) and 38.4% was identified as being intermediate risk (10 trisomy 21 pregnancies and 6190 unaffected pregnancies; prevalence, 1 : 620). A similar distribution was found in the prospective arm of the study. There was no reduction of overall screening performance compared with our current first‐trimester combined screening program. The number of intermediate‐risk pregnancies was sufficiently low as to enable advanced ultrasound scanning by well‐trained sonographers only.ConclusionIn population screening for fetal trisomy 21, sequential triage in the first trimester can be achieved using very simple methods. Pregnancies at high or at low risk can be identified easily and the number of pregnancies at intermediate risk can be reduced sufficiently to enable advanced ultrasound scanning by well‐trained sonographers only. A prospective study is needed to evaluate the performance of this approach and to compare its results with current combined or integrated screening algorithms. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Visibility of the polypropylene tape after tension‐free vaginal tape (TVT) procedure in women with stress urinary incontinence: comparison of introital ultrasound and magnetic resonance imaging in vitro and in vivo
Authors: Schuettoff S. , Beyersdorff D. , Gauruder‐Burmester A. , Tunn R. 
Published: May 2006

AbstractObjectiveTo determine whether introital sonography and magnetic resonance imaging (MRI) after TVT (tension‐free vaginal tape) insertion can depict the polypropylene tape, and thus be used for patient follow‐up.MethodsThe study comprised an experimental part, which investigated in‐vitro visualization of the polypropylene tape in a model (phantom), and a clinical part, in which 20 women (mean age, 53.4 years) with clinically and urodynamically proven stress urinary incontinence without prolapse were investigated by introital ultrasound and MRI before and 13 months after the TVT procedure.ResultsIn the phantom, the polypropylene tape was depicted with a low signal intensity by MRI and as a highly echogenic structure by ultrasound. In the clinical study, introital ultrasound in a mediosagittal orientation depicted the vaginal tape in all patients: it was located under either the midurethra (n = 16) or the lower urethra (n = 4), and in either the muscular coat of the urethra (n = 8) or in the urethrovaginal space (n = 12), the tape was either flat (n = 6) or curled up (n = 14), and there was no retropubic visualization of the tape. Overall, depiction by MRI was limited, and was poorer in comparison with ultrasound, especially when the tape had a sub‐ or paraurethral location. Retropubically, however, MRI identified the tape near the periosteum of the pubic bone (55% of cases), in the retropubic space (37.5% of cases), or near the bladder wall (7.5% of cases).ConclusionSonography is recommended for evaluation of the suburethral and paraurethral tape portions, while MRI is suitable for retropubic evaluation after the TVT procedure. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
New models to predict depth of infiltration in endometrial carcinoma based on transvaginal sonography
Authors: De Smet F. , De Brabanter J. , Van den Bosch T. , Pochet N. , Amant F. , Van Holsbeke C. , Moerman P. , De Moor B. , Vergote I. , Timmerman D. 
Published: May 2006

AbstractObjectivesPreoperative knowledge of the depth of myometrial infiltration is important in patients with endometrial carcinoma. This study aimed at assessing the value of histopathological parameters obtained from an endometrial biopsy (Pipelle®de Cornier; results available preoperatively) and ultrasound measurements obtained after transvaginal sonography with color Doppler imaging in the preoperative prediction of the depth of myometrial invasion, as determined by the final histopathological examination of the hysterectomy specimen (the gold standard).MethodsWe first collected ultrasound and histopathological data from 97 consecutive women with endometrial carcinoma and divided them into two groups according to surgical stage (Stages Ia and Ib vs. Stages Ic and higher). The areas (AUC) under the receiver–operating characteristics curves of the subjective assessment of depth of invasion by an experienced gynecologist and of the individual ultrasound parameters were calculated. Subsequently, we used these variables to train a logistic regression model and least squares support vector machines (LS‐SVM) with linear and RBF (radial basis function) kernels. Finally, these models were validated prospectively on data from 76 new patients in order to make a preoperative prediction of the depth of invasion.ResultsOf all ultrasound parameters, the ratio of the endometrial and uterine volumes had the largest AUC (78%), while that of the subjective assessment was 79%. The AUCs of the blood flow indices were low (range, 51–64%). Stepwise logistic regression selected the degree of differentiation, the number of fibroids, the endometrial thickness and the volume of the tumor. Compared with the AUC of the subjective assessment (72%), prospective evaluation of the mathematical models resulted in a higher AUC for the LS‐SVM model with an RBF kernel (77%), but this difference was not significant.ConclusionsSingle morphological parameters do not improve the predictive power when compared with the subjective assessment of depth of myometrial invasion of endometrial cancer, and blood flow indices do not contribute to the prediction of stage. In this study an LS‐SVM model with an RBF kernel gave the best prediction; while this might be more reliable than subjective assessment, confirmation by larger prospective studies is required. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.