bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrospray ionization tandem mass spectrometric characterization of the new functional oligo(ether‐ester)s structure
Authors: Korytkowska‐Wałach Anna , Gibas Mirosław , Neugebauer Dorota , Stolarzewicz Andrzej 
Published: February 2007

AbstractThe oligomeric products obtained by the polymerization of monomethacrylates of oligoethylene glycols possessing up to four oxyethylene units were examined by electrospray ionization mass spectrometry (ESI‐MS). The oligomerization initiated by sodium and potassium hydrides proceeded via Michael‐type addition of hydroxyl groups to carboncarbon double bonds. Extended reaction time caused gelation, especially in the case of the more reactive potassium hydride. This study was focused on the structural assignments of the oligomeric products by use of ion trap multistage mass spectrometry (ESI‐MS2). Precise structural characterization of the individual oligomers was based on fragmentation data. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitation of lower levels of the DNA adduct of thymidylyl(3′‐5′)thymidine methyl phosphotriester by liquid chromatography/negative atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Zhang Fagen , Bartels Michael J. , Pottenger Lynn H. , Gollapudi B. Bhaskar , Schisler Melissa R. 
Published: February 2007

AbstractA sensitive method has been developed for the direct quantitation of the methyl phosphotriester DNA adduct of thymidyl(3′‐5′)thymidine (dTp(Me)dT) from enzymatic DNA hydrolysates prepared from cultured cells treated with low levels of N‐methyl‐N‐nitrosourea (MNU) and methyl methane sulfonate (MMS), by rapid and selective liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI‐MS/MS). The lower limit of quantitation was 0.1 ng/mL (6.4 adducts per 108 nucleotides). Linearity of the calibration curve was greater than 0.999 from 0.1 to 50 ng/mL. Intra‐day precision for three levels of quality control samples ranged from 4.27 to 15.62%. Interday precision ranged from 2.46 to 11.95%. Using this method, the levels of dTp(Me)dT in DNA enzymatic hydrolysates obtained from a series of incubations of mouse lymphoma cells with low doses of MNU (50 µM) were quantified. Copyright © 2007 John Wiley & Sons, Ltd.
Structural determination of the novel fragmentation routes of zwitteronic morphine opiate antagonists naloxonazine and naloxone hydrochlorides using electrospray ionization tandem mass spectrometry
Authors: Joly Nicolas , Vaillant Celine , Cohen Alejandro M. , Martin Patrick , Essassi Mokhtar El , Massoui Mohamed , Banoub Joseph 
Published: February 2007

AbstractElectrospray ionization quadrupole time‐of‐flight (ESI‐QqToF) mass spectra of the zwitteronic salts naloxonazine dihydrochloride 1 and naloxone hydrochloride 2, a common series of morphine opiate receptor antagonists, were recorded using different declustering potentials. The singly charged ion [M+H2HCl]+ at m/z 651.3170 and the doubly charged ion [M+2H2HCl]2+ at m/z 326.1700 were noted for naloxonazine dihydrochloride 1; and the singly charged ion [M+HHCl]+ at m/z 328.1541 was observed for naloxone hydrochloride 2. Low‐energy collision‐induced dissociation tandem mass spectrometry (CID‐MS/MS) experiments established the fragmentation routes of these compounds. In addition to the characteristic diagnostic product ions obtained, we noticed the formation of a series of radical product ions for the zwitteronic compounds 1 and 2, and also the formation of a distonic ion product formed from the singly charged ion [M+HHCl]+ of naloxone hydrochloride 2. Confirmation of the various established fragmentation routes was effected by conducting a series of ESI‐CID‐QqTof‐MS/MS product ion scans, which were initiated by CID in the atmospheric pressure/vacuum interface using a higher declustering potential. Deuterium labeling was also performed on the zwitteronic salts 1 and 2, in which the hydrogen atoms of the OH and NH groups were exchanged with deuterium atoms. Low‐energy CID‐QqTof‐MS/MS product ion scans of the singly charged and doubly charged deuteriated molecules confirmed the initial fragmentation patterns proposed for the protonated molecules. Precursor ion scan analyses were also performed with a conventional quadrupole‐hexapole‐quadrupole tandem mass spectrometer and allowed the confirmation of the genesis of some diagnostic ions. Copyright © 2007 John Wiley & Sons, Ltd.
Formation of Bimetallic Ag–Au Nanowires by Metallization of Artificial DNA Duplexes
Authors: Fischler Monika , Simon Ulrich , Nir Hadar , Eichen Yoav , Burley Glenn A. , Gierlich Johannes , Gramlich Philipp M. E. , Carell Thomas 
Published: February 2007

AbstractUniform bimetallic nanowires, tunable in size, have been grown on artificial DNA templates via a two‐step metallization process. Alkyne‐modified cytosines were incorporated into 900‐base‐pair polymerase‐chain‐reaction fragments. The alkyne modifications serve as addressable metal‐binding sites after conversion to a sugar triazole derivative via click chemistry. Reaction of the Tollens reagent with these sugar‐coated DNA duplexes generates Ag0 metallization centers around the sugar modification sites of the DNA. After a subsequent enhancement step using gold, nanowires ≤10 nm in diameter with a homogeneous surface profile were obtained. Furthermore, the advantage of this two‐step procedure lies in the high selectivity of the process, due to the exact spatial control of modified DNA base incorporation and hence the confinement of metallization centers at addressable sites. Besides experiments on a membrane as a proof for the selectivity of the method, atomic force microscopy (AFM) studies of the wires produced on Si–SiO2 surfaces are discussed. Furthermore, we demonstrate time‐dependent metallization experiments, monitored by AFM.
Identification and functional characterization of phytosulfokine receptor using a ligand‐based approach
Authors: Matsubayashi Yoshikatsu , Shinohara Hidefumi , Ogawa Mari 
Published: February 2007

AbstractAlmost all plant cells, even when fully differentiated, can dedifferentiate and proliferate in vitro to form a callus, in which they can then differentiate to form various organs. These sequential processes can be promoted by exposing the cells to a conditioned medium in which either the same or other cells have previously been grown, indicating the involvement of cell‐to‐cell communication mediated by a chemical factor. This factor was purified from the conditioned medium and identified as a 5‐amino‐acid sulfated peptide. The addition of this peptide, named phytosulfokine (PSK), to the culture medium, even at nanomolar concentrations, significantly promotes cellular proliferation and/or cellular differentiation. We purified a membrane receptor for PSK (PSKR1) by ligand‐based affinity chromatography and identified it as a member of leucine‐rich repeat receptor kinases. The PSK‐binding domain of PSKR1 was further identified by ligand photoaffinity labeling using a novel “on‐column photoaffinity labeling” methodology that allows repeated incorporation of the photoaffinity label. Analysis of loss‐of‐function and gain‐of‐function mutants of the Arabidopsis PSKR1 revealed that PSK signaling affects cellular longevity and potential for growth without interfering with basic plant morphogenesis. These results suggest that PSK represents a new class of hormones that affect the potential for cellular growth and longevity of individual cells via binding to PSKR1, thereby exerting a pleiotropic effect on individual cells in response to environmental conditions. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 356–364; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20090
Preface to a special issue centered on “ligand receptor interactions”
Authors: Nakanishi Koji 
Published: February 2007

AbstractStarting with this issue, the Chemical Record will publish one or two special issues annually centered on special topics. As chemistry becomes increasingly interdisciplinary, bioorganic studies dealing with bioactive ligands necessarily result in accounting for their mode of action or more molecular biological aspects. The articles in this issue are from leading research groups addressing the dynamic aspects of bioactive compounds. Such studies, central in advancing our understanding of Nature, would not have been possible until recent years.
End‐to‐End Compression Anastomosis of The Rectum: A Pig Model
Authors: Kopelman Doron , Lelcuk Shlomo , Sayfan Joel , Matter Ibrahim , Willenz Ehud P. , Zaidenstein Luis , Hatoum Ossama A. , Kimmel Boaz , Szold Amir 
Published: February 2007

AbstractBackgroundGenerations of investigators have attempted to achieve compression bowel anastomosis by a sutureless device, providing temporary support to the tissue and facilitating the natural healing process. The biocompatibility of nickel–titanium alloy has made it attractive for use in medical implants and devices, and several studies have described the creation of a side‐to‐side compression anastomosis in colon surgery with a nickel–titanium clip. We evaluated the feasibility and safety of a newly designed gun for applying a nickel–titanium compression anastomosis ring (CAR) to create an end‐to‐end colorectal anastomosis in a porcine model.Materials and methodsA segment of the proximal rectum was resected in 25 pigs. The bowel ends were anastomosed transanally by an end‐to‐end CAR device. The animals’ follow‐up continued for up to 8 weeks, and included general health status, weight gain, blood tests, and abdominal X‐ray. They were then sacrificed. The anastomoses were studied for burst pressure, anastomotic index, and histopathology.ResultsOne pig died due to iatrogenic bowel injury unrelated to the CAR device. There was no other morbidity/mortality. The other animals recovered and gained weight. Burst pressure studies demonstrated a minimum pressure of 160 mmHg at time point 0 that escalated quickly to >300 mmHg. The mean anastomotic index after 8 weeks was 0.81. Histologic evaluation revealed minimal inflammation and minimal fibrosis at the anastomosis site.ConclusionThe principles of compression anastomosis are better executed with the use of memory shape alloys. The promising results of this novel technique should encourage further studies of this technology.
Surgical and Interventional Visceral Revascularization for the Treatment of Chronic Mesenteric Ischemia—When to Prefer Which?
Authors: Biebl Matthias , Oldenburg W. Andrew , Paz‐Fumagalli Ricardo , McKinney J. Mark , Hakaim Albert G. 
Published: February 2007

AbstractBackgroundThe purpose of the present study was to compare surgical and endovascular revascularization for chronic mesenteric ischemia (CMI).MethodsForty‐nine patients underwent surgical (SG) or endovascular (EG) treatment. Relief of symptoms was considered the primary endpoint; patency, morbidity, and mortality were secondary endpoints. For statistical analysis, significance was assumed if P values ≤ 0.05.ResultsTwenty‐six patients (53%) underwent surgical revascularization; 23 patients (47%), endovascular repair. Mean follow‐up was 25 ± 21 months (SG) versus 10 ± 10 (EG) months (P = 0.07). Except for body mass indices (SG 18.9 ± 2.7 versus EG 23.6 ± 4.8; P = 0.001), preoperative data were comparable. Freedom from symptoms was 100% (SG) versus 90% (EG) after intervention (P = 0.194), and 89% (SG) versus 75% (EG) at the end of follow‐up. Reocclusion or re‐stenosis occurred in 8% (SG) versus 25% (EG) (log‐rank test: P = 0.003), and mesenteric ischemia developed in 0% (SG) versus 9% (EG) (P = 0.04). Reintervention for CMI was required in 0% (SG) versus 13% (EG) (P = 0.01). Surgical patients experienced more early complications (42% versus EG 4%; P = 0.02) and longer hospital stays (11.6 ± 10.9 days versus EG 1.3 ± 0.5 days; P < 0.001). Overall mortality at the end of follow‐up was 31% (SG) versus 4% (EG) (log‐rank test: P = 0.08), including all patients with combined open mesenteric and aortic reconstruction (P = 0.001).ConclusionsSurgical treatment has superior long‐term patency and requires fewer reinterventions, but it is also more invasive with greater morbidity and mortality compared to endovascular treatment. Endovascular techniques may be preferable in patients with significant co‐morbidities, concomitant aortic disease, or indeterminate symptoms.
Codon Y791F Mutations in a Large Kindred: Is Prophylactic Thyroidectomy Always Indicated?
Authors: Vestergaard Peter , Vestergaard Else Marie , Brockstedt Helle , Christiansen Peer 
Published: February 2007

AbstractBackgroundRET proto‐oncogene mutations are associated with medullary thyroid carcinomas usually requiring preventive thyroidectomy in gene carriers. We present a large kindred with the Y791F mutation in the RET proto‐oncogene that did not have medullary thyroid carcinomas.Patients and methodsEight members of a Danish family with the Y791F mutation participated. All gene carriers underwent pentagastrin testing, and measurements of serum calcitonin. In the index person, exons 10, 11, and 13–16 of the RET proto‐oncogene were screened. In the rest of the individuals only exon 13 was analysed. Mutation analysis was done by direct bidirectional sequencing of PCR products on an ABI 3100 Genetic Analyzer (Applied Biosystems, Foster City, CA, USA).ResultsThe index person was screened genetically due to goitre at a young age. A total of 27 members of the family underwent genetic testing. Twelve (44.4%, 95% CI: 25.5–64.7%) had the mutation (age range 13–84 years). None of these had abnormal pentagastrin tests (0%, 95% CI: 0–26.5%). We found no significant differences in basal serum calcitonin concentrations between gene carriers (mean ± SD: 0.16 ± 0.54 pmol/l, n = 11) and non‐gene carriers (0.55 ± 0.86 pmol/l, n = 6, 2 P = 0.29). None showed signs of primary hyperparathyroidism or phaeochromocytoma.ConclusionsThe Y791F RET proto‐oncogene mutation may have a low penetrance. In selected cases, prophylactic thyroidectomy may be replaced by watchful waiting with repeated pentagastrin testing, provided careful evaluation of risks and benefits is performed.
TNM Classification of Thyroid Carcinoma
Authors: Shaha Ashok R. 
Published: February 2007

AbstractBackgroundThe understanding of biology of well‐differentiated thyroid cancer has improved in the last two decades with the detailed understanding of prognostic factors and risk group stratification. The risk groups are crucial in the management of thyroid cancer and overall prognosis.TNM Staging SystemThe TNM staging system has been used in all human cancers, and it adheres to the biology of tumors. The data in thyroid cancer comes from retrospective studies, as there are no prospective randomized trials. The most recent TNM staging system was revised and published (6th edition) in 2002. The major attributes of the staging system include: age as the most important prognostic factor, and age is included in the staging system, below and above the age of 45; T1 tumors are considered to be those below 2 cm; T3 tumors include minor extrathyroidal extension invading the strap muscles; T4 tumors includes T4a and T4b, T4a being operable tumors; all anaplastic cancers are T4, although operable anaplastic thyroid cancers are considered to be T4a.ConclusionThese changes in the TNM system are consistent with our current philosophy in the overall management of thyroid cancer and adjuvant therapy. The N staging system includes N1a and N1b—N1a being level VI lymph nodes, while N1b includes level IV and superior mediastinal and contralateral neck nodes. The TNM staging system helps reporting our data and comparing results in different parts of the world. However, there is no level I evidence in thyroid cancer.
Social outcome in adults with maple syrup urine disease (MSUD)
Authors: Simon E. , Schwarz M. , Wendel U. 
Published: February 2007

SummaryBackground: In MSUD, dietary treatment aims at the protection of the brain from functional disturbances and structural damage by keeping the branched‐chain amino acids in plasma permanently in the near‐normal range. Unfortunately, delay in effective treatment of the neonatal manifestation and poor long‐term metabolic control are common in MSUD patients, leading to impaired cognitive outcome. Some studies have analysed cognitive capacity but only few data are available on social status (educational qualification, interpersonal relationships, lifestyle) in adult patients, which is one measure for the success of treatment. Aim: In this study we analysed sociodemographic data of 22 adult patients suffering from classic or very severe variant MSUD in comparison with data on an age‐matched control collective of the population of Germany. Results: The analysis revealed low educational and professional levels with a low rate of participation in the labour force by adult MSUD patients. The educational level in patients of migrant origin was lower than the educational qualifications in the native patient group. A large number of patients did not live a normal adult life. Patients could not live autonomously, did not have a steady partnership and had no children. Conclusion: Despite substantial improvement in the treatment of MSUD in recent years, unimpaired outcome of patients with classic or very severe variant MSUD remains a rare finding. Care must be further optimized in order to improve intellectual and, thereby, social outcome. Particular care must be exercised in the treatment of migrant patients who offer special problems due to cultural peculiarities and language difficulties.
Secondary alteration of the transferrin isoelectric focusing pattern in a case of bacterial meningitis
Authors: Quintana E. , Gala S. , García‐Cazorla A. , Montero R. , Muñoz‐Almagro C. , Vilaseca M. A. , Briones P. , Artuch R. 
Published: February 2007

SummaryCongenital disorders of glycosylation (CDG) are a group of inherited defects in the synthesis and processing of the linked glycans of glycoproteins and other glycoconjugates. The phenotypic spectrum presents wide variability, and clinical diagnosis is not reliable in most cases. Isoelectric focusing (IEF) of serum transferrin is widely used as a tool to detect CDG. We describe a paediatric patient presenting an altered serum transferrin pattern due to a secondary disorder of glycosylation caused by pneumococcal meningitis (Streptococcus pneumoniae, serotype 19A). During admission, brain CT scan and MRI showed acute ischaemic lesions in brain frontotemporal parenchyma, and enlarged subarachnoidal spaces in the frontal area resembling a chronic injury. This led us to screen for inborn errors of metabolism potentially associated with these findings (homocystinuria, glutaric aciduria, CDG syndromes). Biochemical studies for the screening of these inborn errors of metabolism were normal except for sialotransferrin isoelectric focusing, which showed a type 2 pattern. However, 16 days later, together with the remission of the meningitis process, the sialotransferrin pattern had normalized. The apolipoprotein C‐III (an O‐glycoprotein) profile was normal in all samples analysed. In conclusion, infectious events should be ruled out in the differential diagnosis of CDG syndromes. Furthermore, our findings highlight the possibility that the type 2 IEF pattern of serum sialotransferrin detected in some patients with neonatal death due to organ failure and septic events might be secondary to the infectious process.
Severe infantile type of carnitine palmitoyltransferase II (CPT II) deficiency due to homozygous R503C mutation
Authors: Spiegel R. , Shaag A. , Gutman A. , Korman S. H. , Saada A. , Elpeleg O. , Shalev S. A. 
Published: February 2007

SummaryWe report a patient with severe infantile carnitine palmitoyltransferase II (CPT II) deficiency who died at the age of 3 months. Genetic analysis of the CPT2 gene revealed that the patient was homozygous, and her parents were heterozygous, for a R503C missense mutation. Heterozygosity for R503C, without a second mutation, has previously been reported in symptomatic patients from two families, one with the mild adult myopathic form and one with malignant hyperthermia. In contrast, the R503C heterozygous parents of the patient were entirely asymptomatic, suggesting that additional genetic and/or environmental factors must have contributed to the occurrence of symptoms in previously reported carriers. Our findings indicate that the mutation R503C should be added to the handful of mutations associated with the severe phenotype when present in the homozygous state or combined with another severe mutation.
Warm discharges in cold fresh water. Part 1. Line plumes in a uniform ambient
Authors: KAY ANTHONY 
Published: February 2007

Turbulent buoyant plumes in cold fresh water are analysed, assuming a quadratic dependence of density on temperature. The model is based on the assumption that entrainment velocity is proportional to vertical velocity in the plume. Numerical and asymptotic solutions are obtained for both rising and descending plumes from virtual sources with all possible combinations of buoyancy, volume and momentum fluxes. Physical sources can be identified as points on trajectories of plumes from virtual sources.The zero-buoyancy condition, at which the plume and the ambient have equal densities but their temperatures are on opposite sides of the temperature of maximum density, is of particular importance. If an upwardly buoyant plume rising through a body of water reaches the surface before passing through its zero-buoyancy level, it will form a surface gravity current; otherwise, the plume water will return to the source as a fountain. The height at which zero buoyancy is attained generally decreases as the source momentum flux increases: greater plume velocity produces greater entrainment and hence more rapid temperature change. Descending plumes, if ejected downwards against upward buoyancy, may be classified as strongly or weakly forced according to whether they reach the zero-buoyancy condition before being brought to rest. If they do, they continue to descend with favourable buoyancy; otherwise, they may form an inverted fountain. Once a descending plume has attained downward buoyancy, it can continue to descend indefinitely, ultimately behaving like a plume in a fluid with a linear equation of state. In contrast, a rising plume will eventually come to rest, however large its initial upward buoyancy and momentum fluxes are.
Antioxidants promote establishment of trypanosome infections in tsetse
Authors: MacLEOD E. T. , MAUDLIN I. , DARBY A. C. , WELBURN S. C. 
Published: February 2007

SUMMARYEfficient, cyclical transmission of trypanosomes through tsetse flies is central to maintenance of human sleeping sickness and nagana across sub-Saharan Africa. Infection rates in tsetse are normally very low as most parasites ingested with the fly bloodmeal die in the fly gut, displaying the characteristics of apoptotic cells. Here we show that a range of antioxidants (glutathione, cysteine, N-acetyl-cysteine, ascorbic acid and uric acid), when added to the insect bloodmeal, can dramatically inhibit cell death ofTrypanosoma brucei bruceiin tsetse. Both L- and D-cysteine invoked similar effects suggesting that inhibition of trypanosome death is not dependent on protein synthesis. The present work suggests that antioxidants reduce the midgut environment protecting trypanosomes from cell death induced by reactive oxygen species.