bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biology and treatment of familial hemophagocytic lymphohistiocytosis: Importance of perforin in lymphocyte‐mediated cytotoxicity and triggering of apoptosis
Authors: Henter Jan‐Inge 
Published: August 2002

AbstractFamilial hemophagocytic lymphohistiocytosis (FHL) is, without treatment, an invariably fatal disease of infancy and early childhood characterized by fever, hepatosplenomegaly, pancytopenia, and a widespread accumulation of T‐lymphocytes and macrophages. During recent years, the diagnosis and the survival as well as the understanding of the disease have improved dramatically. Recent studies suggest that FHL is caused by impaired lymphocyt e‐mediated cytotoxicity and defective triggering of apoptosis, and that the symptoms are mediated by a pro‐inflammatory hypercytokinemia. Moreover, specific genetic alterations, mutations in the perforin gene, have been revealed in FHL patients. Perforin, which normally is secreted from cytotoxic T‐lymphocytes and natural killer (NK) cells upon conjugation between effector and target cells, is able to insert into the membrane of the target cell. It there polymerizes to form a cell death‐inducing pore through which toxic granzymes may enter the cell and trigger apoptosis. The establishment of perforin deficiency as a cause of the rapidly fatal disease FHL has demonstrated the essential role of perforin in human immune homeostasis. Med. Pediatr. Oncol. 2002;38:305–309. © 2002 Wiley‐Liss, Inc.
Complete assignment of 1H and 13C NMR spectra of new pentacyclic triterpene acid benzyl esters
Authors: Weis Robert , Seebacher Werner 
Published: August 2002

AbstractComplete assignments of 1H and 13C NMR chemical shifts for newly synthesized benzyl esters of oleanolic, ursolic and crataegolic acid based on DEPT, HSQC, HMBC, COSY, TOCSY, NOE and ROESY experiments are reported. Copyright © 2002 John Wiley & Sons, Ltd.
Structure of an unexpected trimer from the reaction of ageratochromene II with aluminum chloride
Authors: Chu Changhu , Hu Jiehan , XU Tao , Xiao Hongbin , Liang Xinmiao 
Published: August 2002

AbstractA new trimer from the reaction of ageratochromene [1] (6,7‐dimethoxy‐2,2‐dimethyl‐1‐benzopyran) with anhydrous aluminum chloride was shown to be 3,4‐dihydro‐6,7‐dimethoxy‐2,2‐dimethyl‐3‐(6′,7′‐dimethoxy‐2′,2′‐dimethyl‐2H‐1‐benzopyran‐4′‐yl)‐4‐(3′,4′‐dihydro‐6′, 7′‐dimethoxy‐2′,2′‐dimethyl‐2H‐1‐benzopyran‐3′‐yl)‐ 2H‐1‐benzopyran. Its structure was confirmed by NMR (1H, 13C, DEPT‐135. COSY, HMBC, HSQC, TOCSY and NOESY), IR, mass spectra and elemental analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and spectral study of (2R,11R)‐2,11‐bis{[(2‐methoxyethoxy)methoxy]methyl}‐1,10‐dibenzyl‐4,7,13,16‐tetraoxa‐1,10‐diaza‐cyclooctadecane
Authors: Joly Jean‐Pierre , Walker Olivier , Mutzenhardt Pierre 
Published: August 2002

AbstractA new C2‐symmetric chiral lariat ether has been prepared by 1 : 1 cyclocondensation of a contrafunctional amine easily obtained from L‐serine. Its 1H and 13C spectra were completely assigned using the two‐dimensional gradient enhanced one‐bond (HMQC) and multiple‐bond (HMBC) heteronuclear techniques together with the homonuclear DQF COSY correlation technique. Copyright © 2001 John Wiley & Sons, Ltd.
Reassignment of NMR spectra and conformational study of the sesquiterpene lactone goyazensolide
Authors: Perry Katia S. P. , Miguez Eduardo , de Amorim Mauro B. , Boaventura Maria Amelia D. , da Silva Antonio Jorge R. 
Published: August 2002

AbstractWe describe the reassignment of 13C NMR signals of goyazensolide based upon 1D and 2D techniques, and discuss its conformation and stereochemistry as obtained from the analysis of its proton spin–spin coupling constants, NOE measurements and molecular mechanics calculations using MM3* force field. Copyright © 2001 John Wiley & Sons, Ltd.
Sequential resonance assignment from two‐dimensional inter‐ and intra‐residue 15N–1H correlation spectra
Authors: Perttu Permi , Arto Annila 
Published: August 2002

AbstractSequential assignment of amide resonances in proteins and peptides can conveniently be derived from two‐dimensional inter‐residue 15Ni–1HN(i−1) and intra‐residue 15Ni–1HNi correlation spectra. The inter‐residue 15Ni–1HN(i−1) correlation spectrum is generated by recording the 15Ni frequency evolution indirectly and subsequently transferring the magnetization to 1HN(i−1) of the preceding residue for direct detection. The flow of coherence is established by the (H)N(COCAHA)‐TOCSY pulse sequence. Following the path from intra‐residue correlation via inter‐residue correlation to the next intra‐residue correlation results in sequential assignment in two dimensions. This kind of assignment protocol is most amenable to re‐establishing sequential assignments of target proteins perturbed by binding of ligands or alternatively signals of peptide ligands can be traced in studies of structure–function relationships by NMR. Copyright © 2001 John Wiley & Sons, Ltd.
Cyclodimerization of α,β–α′,β′‐unsaturated ketones promoted by samarium diiodide. Complete assignment of the 1H and 13C NMR spectra of hydroxycyclopentylpropenone derivatives
Authors: Lagadec Ronan Le , Chávez María Isabel , Rubio Laura , Cabrera Armando 
Published: August 2002

AbstractThe 1H and 13C NMR chemical shift assignments of hydroxycyclopentylpropenone derivatives, prepared by a highly selective reaction between samarium(II) iodide and unsaturated ketones, are described. Two‐dimensional shift‐correlated experiments (COSY, HMBC, HMQC, NOESY) were used to assign the chemical shifts completely and unambiguously. Copyright © 2001 John Wiley & Sons, Ltd.
Proton, carbon and nitrogen NMR spectroscopic characterization of some bi‐ and trihetaryl compounds
Authors: Hametner Christian , Hattinger Gregor , Röhrling Jürgen , Fröhlich Johannes , Stanetty Peter , Mihovilovic Marko D. 
Published: August 2002

AbstractThe 1H, 13C, and 15N shifts of 10 nitrogen‐containing bi‐ and triaryls are reported, including the coupling constants of the fluoro substituents with all nuclei. The proton and carbon resonances of the hetaryl structures are completely assigned. Copyright © 2001 John Wiley & Sons, Ltd.
A 1H and 13C NMR study of 4,8,9,10‐tetraaryl‐1,3‐diazatricyclo[3.3.1.13,7]decan‐6‐ones
Authors: Vijayakumar V. , Sundaravadivelu M. , Perumal S. , Lycka A. 
Published: August 2002

AbstractThe 1H and 13C NMR spectra of 4,8,9,10‐tetraaryl‐1,3‐diazatricyclo[3.3.1.13, 7]decan‐6‐ones were measured at 400 and 500 and at 100 and 125 MHz, respectively. The chemical shifts were assigned unambiguously using one‐ and two‐dimensional (H,H‐COSY, C,H‐COSY, NOESY, ROESY and HMBC) NMR spectroscopic data. 1D‐INADEQUATE data also provide an independent assignment of the signals of the carbons of the heterocyclic rings. These results clearly indicate the axial orientation of two aryl groups in one piperidone ring and the equatorial orientation, of the other two aryl groups in another ring. Copyright © 2001 John Wiley & Sons, Ltd.
Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced from 1H NMR measurements
Authors: Micha‐Screttas Maria , Heropoulos Georgios A. , Steele Barry R. 
Published: August 2002

AbstractThe radical anions of monosubstituted benzophenones (including 2‐, 3‐ and 4‐methyl‐, 4‐tert‐butyl‐ and 4‐phenylbenzophenone) with lithium, sodium and potassium as countercations in tetrahydrofuran (THF) were studied by paramagnetic solvent 1H NMR shift measurements in the concentration range ca 0.1–1.0 M. In addition to the cation effects, marked positional isomer and substituent effects were found for (1) molar paramagnetism, (2) magnetic state, (3) solubility, (4) structural stability with respect to concentration or addition of cosolvents and (5) rapidity of attainment of their equilibrium structure. The major conclusions which can be drawn are (a) the solvation behavior of the countercation is governed by the anion, (b) an alkyl group in the 4‐position makes the structure of the lithium and sodium monosubstituted benzophenone radical anions concentration dependent and (c) in most cases, alkali metal aromatic ketone radical anions generated by electron transfer from the corresponding naphthalene radical anion attain their equilibrium structure rapidly. The data are interpreted on the basis of the involvement of spin‐triplet interactions within ‘dimers’ or higher clusters. Copyright © 2001 John Wiley & Sons, Ltd.
Enantiomeric differentiation of terpenic olefins by carbon‐13 NMR using chiral binuclear shift reagents
Authors: Baldovini Nicolas , Tomi Félix , Casanova Joseph 
Published: August 2002

AbstractA study of the enantiomeric differentiation of chiral olefinic terpenes by 13C NMR using binuclear shift reagents is reported. The influence of the [binuclear complex]/[substrate] molar ratio on the chemical shifts and the enantiomeric splittings was investigated with six olefinic substrates. For each compound, a distance‐dependent deshielding effect was observed on all nuclei except on the less substituted sp2 carbon. The enantiomeric differentiation was observed on a large number of carbons of each substrate and was principally attributed to the difference in geometry between the diastereoisomeric complexes. This technique was successfully applied to the enantiomeric differentiation of furanodiene, a sesquiterpene with asymmetry due to its conformational rigidity. Copyright © 2001 John Wiley & Sons, Ltd.
1H and 13C NMR and X‐ray diffraction data for a diosgenyl N,O‐protected glucopyranoside
Authors: Myszka Henryk , Bednarczyk Dorota , Ciunik Zbigniew , Kaca Wiesław 
Published: August 2002

AbstractThe assignments of 1H and 13C NMR chemical shifts together with x‐ray diffraction data for synthesized diosgenyl 3,4,6‐tri‐O‐acetyl‐2‐deoxy‐2‐tetrachlorophthalimido‐β‐D‐glucopyranoside are described. The structure of this glycoside was established by using homo‐ and heteronuclear two‐dimensional NMR techniques. X‐ray diffraction data for this compound are also reported. Copyright © 2002 John Wiley & Sons, Ltd.
2H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers
Authors: Nakajima Takeshi , Akiyama Tsutomu , Furuya Hidemine 
Published: August 2002

AbstractWe synthesized three partially deuterated polymer samples, namely a poly(ethylene‐alt‐propylene) (EP) alternating copolymer, a poly(styrene‐b‐EP) diblock copolymer (SEP) and a poly(styrene‐b‐EP‐b‐styrene) triblock copolymer (SEPS). The 2H spin–lattice relaxation time, T1, of EP soft segments above their glass transition temperature was measured by solid‐state 2H NMR spectroscopy. It was found that the block copolymers had a fast and a slow T1 component whereas EP copolymer had only a fast component. The fast T1 components for SEP and SEPS are similar to the T1 value of EP above ca 20°C. The slow T1 component for SEP and SEPS exhibited a minimum at 60°C and approached the value of the fast component near the Tg of polystyrene. The motional behavior of the EP units for SEP is similar to that of SEPS over the entire range of temperature. Copyright © 2001 John Wiley & Sons, Ltd.
Presence of angiotensin‐converting enzyme in follicular fluids of porcine ovaries and its possible involvement in the intrafollicular breakdown of bradykinin
Authors: Matsui Hitoshi , Takahashi Takayuki 
Published: August 2002

AbstractThe follicular fluid of porcine ovaries contains a metalloenzyme capable of hydrolyzing the synthetic substrate, benzyloxycarbonyl‐Val‐Lys‐Met‐MCA. This enzyme was purified by ammonium sulfate fractionation followed by column chromatography on DEAE‐cellulose, CM‐cellulose, Zn2+‐chelating Cellulofine, and Diol‐300 gel‐filtration columns. The molecular weight of the purified enzyme was estimated to be 170,000 by SDS–PAGE and 400,000 by gel‐filtration analysis, suggesting that the native enzyme is a dimer of the 170‐kDa subunit polypeptide. The enzyme activity was drastically enhanced by the presence of chloride ion, and strongly inhibited by captopril and bradykinin potentiator B. A 9‐residue peptide containing a processing site of human amyloid precursor protein was degraded by its dipeptidyl carboxypeptidase activity. Furthermore, the purified protein was recognized by specific antibody raised against human angiotensin‐converting enzyme. The enzyme rapidly degraded bradykinin in vitro. These results indicate that benzyloxycarbonyl‐Val‐Lys‐Met‐MCA‐hydrolyzing enzyme is a porcine angiotensin‐converting enzyme, and that the enzyme may play a role in bradykinin turnover within the follicles of porcine ovaries. Mol. Reprod. Dev. 62: 99‐105, 2002. © 2002 Wiley‐Liss, Inc.
Nuclear ultrastructure in bovine oocytes after inhibition of meiosis by chemical and biological inhibitors
Authors: Faerge I. , Mayes M. , Hyttel P. , Sirard M.A. 
Published: August 2002

AbstractVarious components of the ovarian follicle as well as different chemicals can suppress the resumption of meiosis in cumulus‐oocyte complexes (COCs). In this study the nuclear ultrastructure of bovine COCs was assessed after 8 h of meiotic inhibition with 50 μM roscovitine (ROSC), 50 μM butyrolactone (BL‐I), 2 mM 6‐DMAP, 2 μM cycloheximide (CX), or a theca cell monolayer (TC). COCs were recovered according to standard in vitro methods, cultured in a simple and defined medium, and processed for transmission electron microscopy. Control COCs were processed before onset of culture and multiple oocytes were evaluated for each treatment. In all groups, the oocyte nucleus presented a dense fibrillar nucleolus consisting of a fibrillar sphere with a fibrillar center. In TC and 6‐DMAP inhibited COCs condensed chromatin adhered to the nucleolus while in all other groups the perinuclear chromatin was separated from the nucleolus. In ROSC inhibited COCs, the nuclear envelope presented only slight small amplitude undulation. The BL‐I‐inhibited COCs presented an intermediate level of low amplitude undulation of the NE. In CX, 6‐DMAP, and TC inhibited COCs the nuclear envelope presented extensively low amplitude undulations. In ROSC inhibited COCs, electron‐dense granules formed ring‐shaped structures. In some of the BL‐I inhibited COCs multiple stellate crystal‐like structures were found, and in these COCs the nuclear envelope and the perinuclear cisternae appeared less distinct than in the other BL‐I inhibited COCs. In 6‐DMAP inhibited COCs interchromatin‐like granule clusters were present. In conclusion, the oocyte nuclei in all COCs presented a dense fibrillar nucleolus resembling that in control COCs. However, variations were observed in 1) the nuclear envelope morphology; 2) the chromatin location in relation to the nucleolus; and 3) the presence of different populations of intranuclear granules. Although all treatments inhibited oocyte nucleus breakdown, the mechanisms underlying these effects are different and require further characterization. Mol. Reprod. Dev. 59: 459–467, 2001. © 2001 Wiley‐Liss, Inc.
Effect of blastomere sex and fluorescent labelling on the development of bovine chimeric embryos reconstituted at the four‐cell stage
Authors: Rho Gyu‐Jin , Kang Tae‐Young , Kochhar Harpreet P.S. , Hahnel Ann C. , Betteridge Keith J. 
Published: August 2002

AbstractThe development rate of bovine chimeric embryos reconstituted at the 4‐cell stage is relatively low. If chimerism is to be used as an approach in producing transgenic livestock, it is important to investigate whether this rate is affected by the sex of the blastomeres being combined and if all blastomeres survive equally well. In Experiment 1, blastomeres from 4‐cell stage embryos were inserted into surrogate zonae pellucidae either in pairs to reconstitute 4‐cell chimeras, or as the original sets of four to make handled controls. The development of chimeras with one pair of blastomeres labelled with PKH26‐GL was also investigated. The rate of development into blastocysts was similar in chimeras with unlabelled blastomeres (23%) and in those in which one pair of blastomeres was labelled (26%) and was lower (P < 0.001) than in the handled and IVF control groups (43 and 58%, respectively). Labelled cells were distributed approximately evenly between ICM and trophoblast. In Experiment 2, the effect of sex differences between pairs of blastomeres in chimeras was investigated; chimeras were reconstituted from pairs of blastomeres taken from 4‐cell embryos in which the remaining pair was sexed by PCR. No significant differences according to the sex of constituent blastomeres were detectable (mixed sex, 27%; males, 24%; females, 21%; P > 0.05). These results suggest that, in addition to the negative effects of micromanipulation, factors other than the sex of the blastomeres are involved in the reduced rate of development of chimeric bovine embryos. They also confirm the usefulness of PKH26‐GL labelling for tracking the progeny of cleaving bovine blastomeres at least to the blastocyst stage. Mol. Reprod. Dev. 60: 202–207, 2001. © 2001 Wiley‐Liss, Inc.
Social relationships in the workplace
Authors: Chadsey Janis , Beyer Steve 
Published: August 2002

AbstractAs more workers with disabilities are competitively employed, there are numerous opportunities to form social relationships with their co‐workers. Close social relationships are associated with a number of positive outcomes (e.g., happiness, less stress) and should be actively pursued for those individuals desiring them. In this paper, we describe the types of social interactions displayed in work settings employing workers with and without disabilities. We also discuss some of the social problems experienced by some workers with disabilities. Finally, we describe two general categories of intervention strategies that have been used to impact social relationships: (a) strategies that involve changing the social behaviors of workers with disabilities, and (b) natural support strategies. The results from these strategies are discussed, and future areas of research are described. MRDD Research Reviews 7:128–133, 2001. © 2001 Wiley‐Liss, Inc.
Excitotoxicity in neonatal hypoxia
Authors: Johnston Michael V. 
Published: August 2002

AbstractHypoxic‐ischemic encephalopathy (HIE) in neonates is a disorder of excessive neuronal excitation that includes seizures, abnormal EEG activity, and delayed failure of oxidative metabolism with elevated levels of lactic acid in the brain. Evidence from experimental models and clinical investigation indicates that HIE is triggered by a profound disruption in the function of glutamate synapses so that re‐uptake of glutamate from the synapse is impaired and post‐synaptic membranes containing glutamate receptors are depolarized. Severe hypoxemia preferentially depolarizes neuronal membranes, while ischemia probably has greater impact on the activity of glial glutamate re‐uptake. Together, severe hypoxia and ischemia trigger a delayed cascade of events that may result in cell death by necrosis and/or apoptosis. Apoptosis is far more prominent in the neonate than in the adult and activation of cysteine proteases such as caspase‐3 is a very important pathway in excitotoxic neonatal injury. Understanding the complex molecular networks triggered by an excitotoxic insult in the neonate provides insight into patterns of selective neuronal vulnerability and potential therapeutic strategies. MRDD Research Reviews 2001;7:229–234. © 2001 Wiley‐Liss, Inc.
Experimental investigation of RF magnetic field homogeneity in a bridged loop‐gap resonator
Authors: Ono Mitsuhiro , Suenaga Akihiko , Hirata Hiroshi 
Published: August 2002

AbstractThe relationship between an RF magnetic field and an electric shielding plate called a bridge in a bridged loop‐gap resonator (BLGR), which is used for EPR spectroscopy and imaging, is examined. The magnetic field in a BLGR is perturbed due to discontinuity of the conductive loop and electric fringing fields near the gaps. The magnetic field homogeneity in the BLGR can be improved with a bridge. The optimum angle for such bridges can be found by measuring the RF magnetic field. In this study, the RF magnetic field was measured for BLGRs 70 mm in diameter, with a resonance frequency of 302 ± 5 MHz. The field uniformity on a circle with a radius of 27 mm was improved by 8% with bridges at optimal angles. Improved RF magnetic field homogeneity associated with a BLGR is demonstrated. Magn Reson Med 47:415–419, 2002. © 2002 Wiley‐Liss, Inc.
Elimination of Nyquist ghosting caused by read‐out to phase‐encode gradient cross‐terms in EPI
Authors: Grieve Stuart M. , Blamire Andrew M. , Styles Peter 
Published: August 2002

AbstractEcho‐planar imaging (EPI) commonly suffers from ghosting artifacts caused by zero‐ or first‐order phase differences between the odd and even echoes that constitute an EPI dataset. Small‐bore imaging systems with shielded gradients may suffer significantly from cross‐term eddy currents due to the high degree of manufacturing precision required in such systems compared to larger whole‐body coils. A Nyquist ghost caused by cross‐term eddy current contributions from the read‐out to the phase‐encode axis was identified in a small‐bore system and characterized using a modified EPI experiment and a computer simulation. The artifact was corrected for using both a postprocessing approach and compensation blips along the phase‐encode axis. Correction using compensation blips proved to be a more effective strategy to reduce this artifact than the postprocessing method used. Magn Reson Med 47:337–343, 2002. © 2002 Wiley‐Liss, Inc.
Correction of physiologically induced global off‐resonance effects in dynamic echo‐planar and spiral functional imaging
Authors: Pfeuffer Josef , Van de Moortele Pierre‐Francois , Ugurbil Kamil , Hu Xiaoping , Glover Gary H. 
Published: August 2002

AbstractIn functional magnetic resonance imaging, a rapid method such as echo‐planar (EPI) or spiral is used to collect a dynamic series of images. These techniques are sensitive to changes in resonance frequency which can arise from respiration and are more significant at high magnetic fields. To decrease the noise from respiration‐induced phase and frequency fluctuations, a simple correction of the “dynamic off‐resonance ink‐space” (DORK) was developed. The correction uses phase information from the center ofk‐space and a navigator echo and is illustrated with dynamic scans of single‐shot and segmented EPI and, for the first time, spiral imaging of the human brain at 7 T. Image noise in the respiratory spectrum was measured with an edge operator. The DORK correction significantly reduced respiration‐induced noise (image shift for EPI, blurring for spiral, ghosting for segmented acquisition). While spiral imaging was found to exhibit less noise than EPI before correction, the residual noise after the DORK correction was comparable. The correction is simple to apply and can correct for other sources of frequency drift and fluctuations in dynamic imaging. Magn Reson Med 47:344–353, 2002. © 2002 Wiley‐Liss, Inc.