bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mid‐gestation Down syndrome screening test and pregnancy outcome among unstimulated assisted‐conception pregnancies
Authors: Shulman Adrian , Maymon Ron 
Published: August 2003

AbstractObjectivesAlteration of mid‐gestation serum markers in assisted‐conception pregnancies is believed to be attributable to ovarian superovulation treatment modalities. We compared alpha‐fetoprotein (AFP), human chorionic gonadotrophin (hCG), and unconjugated estriol (uE3) in two groups of unstimulated assisted‐conception pregnancies, that is, own‐oocyte frozen embryos (own‐FET) versus oocyte‐donated (OD) embryos.MethodsForty‐three OD‐conceived and 31 own‐FET‐conceived singleton parturient women (aged 29 ± 4 years and 31 ± 4 years respectively, P < 0.05) were followed from embryo transfer throughout pregnancy.ResultsThe daily pattern of first‐trimester serum β‐hCG was similar in both groups. The OD group had only significantly increased AFP concentrations compared to the own‐FET group (1.38 vs 0.99 median MoM respectively, P = 0.002). Although there were no chromosomal abnormalities and no fetal or neonatal deaths in either group, 12% OD women and 6.5% own‐FET women were found screen‐positive. Eight OD women and 11 FET women had an adverse obstetric outcome (P = NS).ConclusionOD embryos are a unique clinical model for evaluating the uterine compartment and its contribution to mid‐gestation serum marker secretion. Copyright © 2003 John Wiley & Sons, Ltd.
Liquid chromatography/mass spectrometric determination of patulin in apple juice using atmospheric pressure photoionization
Authors: Takino Masahiko , Daishima Shigeki , Nakahara Taketoshi 
Published: August 2003

AbstractThis paper describes a comparison between atmospheric pressure chemical ionization (APCI) and the recently introduced atmospheric pressure photoionization (APPI) technique for the liquid chromatography/mass spectrometric (LC/MS) determination of patulin in clear apple juice. A column switching technique for on‐line extraction of clear apple juice was developed. The parameters investigated for the optimization of APPI were the ion source parameters fragmentor voltage, capillary voltage, and vaporizer temperature, and also mobile phase composition and flow rate. Furthermore, chemical noise and signal suppression of analyte signals due to sample matrix interference were investigated for both APCI and APPI. The results indicated that APPI provides lower chemical noise and signal suppression in comparison with APCI. The linear range for patulin in apple juice (correlation coefficient >0.999) was 0.2–100 ng mL−1. Mean recoveries of patulin in three apple juices ranged from 94.5 to 103.2%, and the limit of detection (S/N = 3), repeatability and reproducibility were 1.03–1.50 ng mL−1, 3.9–5.1% and 7.3–8.2%, respectively. The total analysis time was 10.0 min. Copyright © 2003 John Wiley & Sons, Ltd.
Investigation of sample preparation and instrumental parameters in the matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry of noncovalent peptide/peptide complexes
Authors: Zehl Martin , Allmaier Günter 
Published: August 2003

AbstractThe application of matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) to the direct detection and investigation of noncovalent solution‐phase complexes is far from being routine and some principal problems and questions still exist. Therefore, this study systematically investigates several main problems, namely, the effect of sample preparation and some instrument‐related parameters on the stability of the noncovalent complexes as well as the formation of nonspecific cluster ions in the case of the MALDI‐MS analysis of specific peptide/peptide complexes. The complexes formed between biologically active fragments of human gastrin I, which contain the sequence motif EEEEE, and different peptides, which contain the interacting sequence motifs RR and RKR, were chosen as examples. A broad variety of MALDI matrices and sample preparation protocols were screened systematically and evaluated. The two ‘less acidic’ matrices 2,4,6‐trihydroxyacetophenone and 6‐aza‐2‐thiothymine, in combination with carefully selected solvents and additives, turned out to allow the reproducible detection of the solution‐phase peptide/peptide complexes with good intensity, whereas the classical MALDI matrices could not be applied with the same success. Because both matrices also tend to induce the formation of nonspecific cluster ions, control experiments using nonbinding peptides were performed to definitely prove the specificity of the detected complexes. In contrast to the sensitivity of the peptide/peptide complexes to solution‐phase conditions, the gas‐phase stability during desorption/ionization was found to be extraordinary high. Neither the application of high laser fluence nor switching from continuous to delayed extraction mode as well as variation of the delay time up to 520 ns had considerable effect on the relative intensities of the specific peptide/peptide complexes. Copyright © 2003 John Wiley & Sons, Ltd.
Differentiation of isomeric flavone/isoflavone aglycones by MS2 ion trap mass spectrometry and a double neutral loss of CO
Authors: Kuhn Fabian , Oehme Michael , Romero Fernando , Abou‐Mansour Eliane , Tabacchi Raffaele 
Published: August 2003

AbstractThe fragmentation behaviour of seven pairs of isomeric flavone/isoflavone aglycones (solely hydroxylated and/or methoxylated) was studied using ion trap mass spectrometry with atmospheric pressure ionisation (API, both electrospray and APCI) in the positive and negative ion modes. A major difference was found in the neutral loss of 56 u, which was a common feature of all isoflavones in API(+). It was identified as a double loss of CO by accurate mass tandem mass spectrometric (MS/MS) measurements using a hybrid quadrupole time‐of‐flight (Q‐TOF) instrument. Fragmentation of daidzein with 13C‐isotope labelling of the carbon C2 showed that this double loss occurred from the central ring of the molecule. A mechanism for this selective fragmentation is given. Further isoflavone‐specific fragmentations were used to develop a guideline for the identification of isoflavone structures. A software‐based neutral loss scan of 56 u in the API(+)‐MS2 mode was applied to extracts of leaves of Lupinus albus and to soy flour. The structure elucidation guideline allowed identification of hydroxy and/or methoxy isoflavones. Structures could be confirmed for those available as reference compounds. Copyright © 2003 John Wiley & Sons, Ltd.
Comparison of storage techniques for giant panda sperm
Authors: Ann Olson Mary , Yan Huang , DeSheng Li , Hemin Zhang , Durrant Barbara 
Published: August 2003

AbstractSemen storage for artificial insemination is an integral part of giant panda captive breeding programs. The development of short‐ and long‐term storage techniques is needed to ensure a viable reserve of germplasm for artificial reproduction. In this study semen collected by electroejaculation from three male pandas was extended in culture medium prior to recording initial motility (MOT), speed of progression (SOP), and percent live (% L). Motility scores (MS) were calculated as MOT×SOP2. All results were expressed as % of initial MS (% IMS) and % of initial L (% IL). Experiment 1 examined the longevity of cooled sperm, both fresh and thawed. Extended fresh sperm was diluted in TEST‐Y buffer before storage at 4°C. The % IMS and % IL were recorded at 4, 8, 24, and 48 hr for males 1 and 2, and at 29, 70, and 214 hr for male 3. Additional sperm was frozen over liquid nitrogen vapor following dilution in TEST‐Y buffer with 4% glycerol and cooling to 4°C. The % IL of fresh sperm after 48 hr at 4°C was 96 and 100 for males 1 and 2, respectively. In contrast, thawed sperm from these males exhibited just 77 and 68% IL at thaw (T0). These data indicate that short‐term liquid storage is superior to freezing when sperm is to be used within 48 hr of collection. Experiment 2 compared the effects of four cooling methods on the cryosurvival of panda sperm. Sperm from male 3 was diluted in TEST‐Y buffer with 4% glycerol and cooled by four methods. Vials were frozen over liquid nitrogen vapor and stored for 5 months in liquid nitrogen. The sperm was thawed and evaluated for % IL at T0, and then reevaluated at 30 and 60 min at 37°C. There was no significant effect of the prefreeze cool method on % IMS or % IL. Zoo Biol 22:335–345, 2003. © 2003 Wiley‐Liss, Inc.
Endocrine monitoring and its application to the management of the giant panda
Authors: Czekala Nancy , McGeehan Laura , Steinman Karen , Xuebing Li , Gual‐Sil Fernando 
Published: August 2003

AbstractUrinary estrogens (n=10) and progestins (n=4) were monitored in a total of 10 giant panda females. Estrogens were evaluated with two different immunoassays during the estrous period. The two different methodologies gave similar hormonal profiles, but different quantitative results due to differences in the crossreactivity of the different assay systems. High‐pressure liquid chromatography (HPLC) analysis of peak estrogen urine revealed that estrone sulfate was the major component, and estrone glucuronide was a minor component (97:3). A comparison of days of insemination in females that conceived and delivered offspring showed a correlation to insemination on days 1 and 2 post‐estrogen peak. An analysis of urinary progestins revealed that they were elevated over baseline concentrations following the estrogen surge during estrus (P<0.0004). Zoo Biol 22:389–400, 2003. © 2003 Wiley‐Liss, Inc.
Actin expression in Taenia solium cysticerci (cestoda): tisular distribution and detection of isoforms
Authors: Ambrosio Javier R. , Reynoso‐Ducoing Olivia , Hernández‐Sanchez Hugo , Correa‐Piña David , González‐Malerva Laura , Cruz‐Rivera Mayra , Flisser Ana 
Published: August 2003

AbstractIdentification, localization and partial biochemical characterization of actins expressed in the larval stage of the cestode parasite Taenia solium has been carried out. Frozen tissue sections of cysticerci, the larval stage of this parasite, were reacted with rhodamine‐phalloidin, parasite actin was purified by polymerization in the presence of K+, mg++and ATP actin was analyzed by SDS—PAGE and two‐dimensional gel electrophoresis, and immunoblotting of actin was performed in PVDF membranes and with commercial anti‐actin monoclonal antibodies. Parasitic tissues showed different fibrous actin fluorescence patterns, which correlated with the expression of isoactins. Purified globular actin had a similar molecular mass to rabbit commercial actin (∼44 kDa). Actin was resolved into seven isoforms, indicating a family of actin genes.
Anterior rectal wall excision for endometriosis using the circular stapler
Authors: Woods Rodney J. , Heriot Alexander G. , Chen Frank C. 
Published: August 2003

Background:  Endometriosis involving the rectum is rare but is associated with significant symptoms that are best relieved by resection of the involved segment of rectum. Resection necessitates either a segmental or anterior rectal wall excision with sutured closure. Application of a circular stapling device allows an alternative technique to resect endometriosis in this area.Method:  Following laparascopic ablation of endometriosis elsewhere in the pelvis, the rectum must be mobilized around disease present on the anterior rectal wall. This will involve lateral and anterior extraperitoneal rectal dissection; the latter dissection mobilizing the vagina from the rectum by a sufficient length necessary to allow imbrication of the diseased area. Insertion of a circular stapler per anus allows the diseased area to be imbricated into the stapler, resulting in simultaneous excision and closure of the anterior rectal wall.Results:  Thirty patients with anterior rectal wall endometriosis, estimated at <2 cm in diameter and not involving > one‐third of the total circumference of the rectum, have undergone successful management using this technique. Morbidity occurred in four patients, with one patient requiring further surgery.Conclusions:  Laparascopic disc excision of deposits of endometriosis involving the anterior rectal wall can be safely performed utilizing the circular stapler without the need for open surgery, and with low morbidity.
Long‐term comparison of external valvular stenting and stripping of varicose veins
Authors: Lane Rodney J. , Graiche Joseph A. , Coroneos John C. , Cuzzilla Michael L. 
Published: August 2003

Background:  The recurrence rate following stripping of the long saphenous vein is unacceptable. Repair of the terminal valve of the long saphenous vein is a physiological alternative. The aim of the present study was to prospectively compare the long‐term recurrence rates in patients having had reparative and ablative procedures at the same time.Methods:  Patients were grouped first into those receiving high ligation and stripping of the long saphenous vein in one limb and valve repair on the contralateral side. The second group consisted of those patients who received short saphenous vein removal and valve repair of the ipsilateral long saphenous system. Finally, the effect of pregnancy on patients who received valve repairs was also studied. All patients were examined postoperatively clinically and with duplex ultrasound.Results:  Cumulative and absolute recurrence rates for both procedures were analysed. Over the 13‐year follow‐up period, external valvular stenting produced a superior outcome. The effect of pregnancy on the venous valve repair cases resulted in recurrences in 23% of cases but there was no evidence of incompetence at the site of the valve repair.Conclusion:  If a valve repair is possible at the saphenofemoral junction, then it should be the preferred treatment option.
Unsupervised Curve Clustering using B‐Splines
Authors: Abraham C. , Cornillon P. A. , Matzner‐Løber E. , Molinari N. 
Published: August 2003

AbstractData in many different fields come to practitioners through a process naturally described as functional. Although data are gathered as finite vector and may contain measurement errors, the functional form have to be taken into account. We propose a clustering procedure of such data emphasizing the functional nature of the objects. The new clustering method consists of two stages: fitting the functional data by B‐splines and partitioning the estimated model coefficients using a k‐means algorithm. Strong consistency of the clustering method is proved and a real‐world example from food industry is given.
Chemie und Biologie der DNA‐Reparatur
Authors: Schärer Orlando D. 
Published: July 2003

AbstractZahlreiche Agentien endogenen und exogenen Ursprungs schädigen die DNA in unserem Genom. Es existieren unterschiedliche Reparatursysteme, die Schäden in der DNA erkennen und durch eine Vielzahl von Reaktionssequenzen beheben können. Defekte DNA‐Reparaturproteine hängen mit einigen erblich bedingten Syndromen zusammen, die eine Prädisposition für Krebs aufweisen. Während die DNA‐Reparatur einerseits essenziell für eine gesunde Zelle ist, beeinträchtigen DNA‐Reparaturenzyme andererseits die Effizienz vieler Antitumorwirkstoffe, deren Wirkung auf der Schädigung von DNA beruht, sodass DNA‐Reparaturenzyme auch hinsichtlich des Wirkstoff‐Designs von großer Bedeutung sind. DNA‐Reparaturprozesse variieren stark in ihrer Art und Komplexität. Während in einem Fall nur ein einziges Enzym benötigt wird, ist an anderen Pfaden ein koordiniertes Zusammenspiel von dreißig oder mehr Proteinen beteiligt. Unser Kenntnisstand der genetischen, biochemischen und strukturellen Grundlagen der DNA‐Reparatur und damit verwandter Prozesse hat sich in den letzten Jahren stark verbessert. Dieser Aufsatz fasst die jüngsten Forschungsergebnisse auf diesem Gebiet zusammen.
Selektivität in der Analytischen Chemie
Authors: Danzer Klaus 
Published: July 2003

AbstractDie korrekte Verwendung des Begriffs “Selektivität” in der Analytischen Chemie wird diskutiert, insbesondere seine Unterscheidung vom Begriff “Spezifität”. Des Weiteren wird eine Definition des Begriffs Selektivität gegeben und empfohlen, nur diesen Begriff in der Analytischen Chemie zu verwenden.
Die Begriffe Selektivität und Spezifität beschreiben unterschiedliche Eigenschaften analytischer Systeme. Sie sollten deshalb streng unterschieden werden; siehe dazu Lit. 32. In dieser Empfehlung geht es um Selektivität, und in diesem Sinne sollte Spezifität nicht verwendet werden.
Hadamard‐Transformations‐Flugzeitmassenspektrometrie: gesteigerte Signalintensität bei gleicher Messzeit
Authors: Zare Richard N. , Fernández Facundo M. , Kimmel Joel R. 
Published: July 2003

AbstractDie Hadamard‐Transformations‐Flugzeit(HT‐TOF)‐Massenspektrometrie ist eine massenspektrometrische Methode, die kontinuierlich strahlende Ionenquellen mit der Puls‐Technik von Flugzeitmessungen kombiniert. Anders als die konventionelle TOF‐Massenspektrometrie hat die Hadamard‐Transformations‐Methode einen Auslastungszyklus von 50 % mit der Möglichkeit zur Erweiterung auf 100 %. Da es sich um ein Multiplex‐Verfahren handelt, ist das erreichbare Signal‐Rausch‐Verhältnis bedeutend höher als bei der konventionellen TOF‐Massenspektrometrie. Der vorliegende Kurzaufsatz stellt die grundlegenden Prinzipien der HT‐TOF‐Massenspektrometrie, des hohen Auslastungszyklus und des Signal‐Rausch‐Verhältnisses vor. Diese Vorteile eröffnen eine Spektrenaufnahmegeschwindigkeit, die schneller ist als die von vergleichbaren Geräten: Detektoren für Hochgeschwindigkeits‐Trennungen sind somit in greifbare Nähe gerückt.
Eine chemische Denksportaufgabe: die Totalsynthese von Gelsemin
Authors: Lin Hong , Danishefsky Samuel J. 
Published: July 2003

AbstractDie Totalsynthese von Gelsemin und 21‐Oxogelsemin ist auf mehreren Wegen möglich. In diesem Aufsatz werden die zentralen Elemente der unterschiedlichen Synthesestrategien zusammengefasst und die Ansätze zum Aufbau des Bicyclo[3.2.1]octan‐Kerns, zur Einführung des quartären Brückenkopf‐Kohlenstoffatoms C20 bei der Bildung der Pyrrolidineinheit, zum Aufbau des Oxindol‐Rests und zum Ringschluss des Tetrahydropyranrings diskutiert.
Chemistry and Biology of DNA Repair
Authors: Schärer Orlando D. 
Published: July 2003

AbstractNumerous agents of endogenous and exogenous origin damage DNA in our genome. There are several DNA‐repair pathways that recognize lesions in DNA and remove them through a number of diverse reaction sequences. Defects in DNA‐repair proteins are associated with several human hereditary syndromes, which show a marked predisposition to cancer. Although DNA repair is essential for a healthy cell, DNA‐repair enzymes counteract the efficiency of a number of important antitumor agents that exert their cytotoxic effects by damaging DNA. DNA‐repair enzymes are therefore also targets for drug design. DNA‐repair processes differ greatly in their nature and complexity. Whereas some pathways only require a single enzyme to restore the original DNA sequence, others operate through the coordinated action of 30 or more proteins. Our understanding of the genetic, biochemical, and structural basis of DNA repair and related processes has increased dramatically over the past decade. This review summarizes the latest developments in this field.
Crystallographic report: Bis[tris(2‐pyridyl)amine]cadmium(II)‐di‐µ‐chloro‐dichloro‐cadmium(II), [(C5H4N)3N]2CdCl2CdCl2
Authors: Xie Yongshu , Liu Xueting , Ni Jia , Jiang Hui , Liu Qingliang 
Published: July 2003

AbstractIn the dinuclear molecule of [(C5H4N)3N]2CdCl2CdCl2, one cadmium is octahedrally coordinated by a Cl2N4 donor set and the other cadmium is tetrahedrally coordinated by four chlorine atoms. The dinuclear units are connected by π–π interactions to give a two‐dimensional network. Copyright © 2003 John Wiley & Sons, Ltd.
Metal‐stabilized rare tautomers: N4 metalated cytosine (M = Li+, Na+, K+, Rb+ and Cs+), theoretical views
Authors: Monajjemi Majid , Ghiasi Reza , Sadjadi M. A. Seyed 
Published: July 2003

AbstractAb initio calculations indicate that metalation of the exocyclic amino group of cytosine by the elements of Group IA (Li, Na, K, Rb and Cs) induces protonation of a nucleobase ring nitrogen atom, and hence causes a proton shift from an exocyclic to an endocyclic nitrogen atom. Thus, this metal‐assisted process leads to the generation of rare nucleobase tautomers. The calculations suggest that this kind of metalation increases the protonation energies of the aromatic ring of the nucleobase. The present study reports the quantum chemistry analysis of the metal‐assisted tautomerization. The calculations clearly demonstrate that metalation of the exocyclic amino group of the nucleobase significantly increases the protonation energy of the aromatic rings of the nucleobase. Also, absolute anisotropy shift, molecular orbital and natural bond orbital calculations are compatible with these results. Copyright © 2003 John Wiley & Sons, Ltd.
High‐throughput single‐nucleotide polymorphism analysis of the IL1RN locus in patients with ankylosing spondylitis by matrix‐assisted laser desorption ionization‐time‐of‐flight mass spectrometry
Authors: Maksymowych Walter P. , Reeve Jeff P. , Reveille John D. , Akey Joshua M. , Buenviaje Heidi , O'Brien Lori , Peloso Paul M. , Thomson Glen T. , Jin Li , Russell Anthony S. 
Published: July 2003

AbstractObjectiveTo examine single‐nucleotide polymorphisms (SNPs) in the 3′ region of the IL1RN gene in a large Caucasoid case–control series and in ankylosing spondylitis (AS) families from Western Canada by use of high‐throughput MassArray matrix‐assisted laser desorption ionization–time‐of‐flight (MALDI‐TOF) mass spectrometry SNP typing.MethodsAn association analysis was performed in a case–control cohort of 394 AS cases and 500 controls. Family‐based association analysis was performed in 58 simplex and 13 multiplex families. Three SNPs located in the 3′ region of the IL1RN gene (T/C at position 27810 in exon 4, T/C at position 30735 in exon 6, and G/C at position 31017 in exon 6) were examined by high‐throughput MassArray MALDI‐TOF mass spectrometry. Haplotype inference software programs were used to infer the most likely haplotypes and to compare haplotype frequencies, which were then further analyzed in family‐based association studies by transmission disequilibrium tests.ResultsThe frequency of allele C at SNP position 30735 in exon 6 was significantly increased in AS cases (35.1%) versus controls (27.8%), as was the phenotype frequency (61.7% versus 48.6%). A significantly increased frequency of SNP allele G at position 31017 in exon 6 in cases (32.9%) versus controls (28.3%) was also noted. A highly significant difference in the overall distribution of haplotype frequencies was evident between cases and controls, with significant increases in the frequencies of the 27810C/30735C/31017C and 27810C/30735T/31017G haplotypes, but a significant reduction in the estimated frequency of the 27810C/30735T/31017C haplotype, in the AS cases. Estimation of haplotype frequencies based on 2 SNP markers indicated a highly significant increase in the 30735C/31017C haplotype and a highly significant decrease in the 30735T/31017C haplotype in cases compared with controls. Preliminary evidence for reduced transmission of the 27810C/30735T/31017C 3‐marker haplotype was also found in family‐based association analyses.ConclusionOur data establish a highly significant disease association with markers in the IL1RN gene. In the absence of nonsynonymous coding sequence substitutions, it is possible that the primary disease‐associated locus regulates gene expression. Association with specific haplotypes raises the possibility that the primary disease locus is in linkage disequilibrium with a specific combination(s) of markers in the IL1RN gene.