bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards the automatic analysis of 1H NMR spectra: Part 2. Accurate integrals and stoichiometry
Authors: Griffiths Lee 
Published: August 2002

AbstractA method was developed for the extraction of accurate NMR integrals, even where partially convoluted with other solute or solvent resonances, and then automatically allocating these to multiplets. The method yields an overall error of 7%, an assessment which includes a statistical distribution of overlapping and touching multiplets. A method was also developed to convert these multiplet integrals automatically from arbitrary units into protons, the overall error remaining at 7%. Copyright © 2001 John Wiley & Sons, Ltd.
1H and 13C chemical shifts for tetracycle‐fused acridine analogues of amsacrine
Authors: Robin M. , Galy J. P. , Faure R. 
Published: August 2002

AbstractThe 1H and 13C NMR resonances for 18 tetracyclic acridines 9‐substituted on the acridine ring with Cl, NH2 and AMS [N‐(4‐amino‐3‐methoxyphenyl)1methanesulfonamide] groups were completely and unequivocally assigned by the concerted application of gs‐HMQC and gs‐HMBC experiments. For NH2 and AMS substituents, the potential amino–imino tautomerism is completely shifted towards the imino tautomer. Copyright © 2001 John Wiley & Sons, Ltd.
Investigation of formation of superoxide anion radical in DMSO by ESR: Part 1. Influence of Fe2+ and Cu2+
Authors: Qiao Xiangli , Chen Shiming , Tan Li , Zheng Hu , Ding Yadi , Ping Zhenghua 
Published: August 2002

AbstractThe superoxide anion radical O2−. can be produced by reactions between dissolved oxygen, DMSO and NaOH. The analysis of DMSO of chemical purity grade showed that there are some ionic impurities such as Fe, Cu and Zn. A systematic study, by electron spin resonance, of the variation of the intensity of the O2−. radical as a function of the ion contents in DMSO showed that the amount of superoxide anion radical produced depends on the Fe2+ and Cu2+ contents in DMSO, but is independent of Zn2+ content. The presence of both Fe2+ and Cu2+ in a certain concentration range greatly favors radical formation. The mechanism of O2−. generation in the presence of Fe2+ and Cu2+in DMSO is discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Complete assignment of the 1H and 13C NMR spectra of resveratrol derivatives
Authors: Koh Dongsoo , Park Kwan Ha , Jung Jihyun , Yang Heejung , Mok K.Hun , Lim Yoongho 
Published: August 2002

AbstractThe complete 1H and 13C chemical shift assignments of six derivatives of resveratrol [(E)‐5‐[2‐(4‐hydroxyphenyl)ethenyl]‐1,3‐benzenediol] that possess leukotriene D4 receptor antagonistic activities are described. Two‐dimensional COSY, HMQC, HMBC and NOESY experiments, along with molecular modeling calculations, were employed to distinguish unambiguously between different configurations of the stilbene moiety. Copyright © 2001 John Wiley & Sons, Ltd.
Assignment of the 13C and 15N NMR spectra of the antitumour antibiotic streptonigrin
Authors: Anderberg Pia I. , Luck Ian J. , Harding Margaret M. 
Published: August 2002

AbstractThe assignments of the two pyridyl nitrogens and two amino nitrogens in the antitumour antibiotic streptonigrin, and all carbon resonances, were determined by 15N (HSQC, HMBC) and 13C (HSQC, HMBC) NMR techniques. These data provide useful probes for determination of the site(s) of metal complexation in the drug, which are important in the mechanism of antitumour activity. Copyright © 2002 John Wiley & Sons, Ltd.
DNA topoisomerase II is essential for preimplantation mouse development
Authors: St. Pierre Jason , Wright David J. , Rowe Thomas C. , Wright Shirley J. 
Published: August 2002

AbstractTopoisomerase II (topo II) is an essential enzyme that alters DNA topology. This activity is important for a variety of chromosome functions including DNA replication, transcription, recombination, and chromosome condensation and segregation. Previously we localized topo II in mouse gametes and preimplantation embryos using isoform‐specific antibodies demonstrating the presence of the enzyme in oocytes and embryos, but not sperm. To probe functions of topo II during preimplantation development, we treated mouse zygotes with 100 nM teniposide, and assessed embryo morphology and DNA replication. Teniposide blocked cleavage in 69% embryos; the remainder cleaved once but had abnormal nuclei. Teniposide‐treated embryos were devoid of topo II immunofluorescence. Teniposide also prevented DNA replication, implicating topo II in this process. Embryos treated with a 2 hr pulse of teniposide recovered and developed to the blastocyst stage, indicating 100 nM teniposide did not induce apoptosis. To more specifically analyze topo IIα function, we treated zygotes with topo IIα‐targeted antisense oligodeoxynucleotides. Most zygotes arrested at the 2‐cell stage while controls developed into blastocysts indicating topo IIα is essential for preimplantation development. The absence of topo IIα, but not β immunofluorescence in antisense‐treated embryos confirms the specificity and impact of the treatment. In addition, topo IIα is newly synthesized at the 2‐cell stage. These results establish an essential function for topo II in mouse preimplantation embryonic development. Mol. Reprod. Dev. 61: 347–357, 2002. © 2002 Wiley‐Liss, Inc.
Androgen receptor and follicle‐stimulating hormone receptor in the pig ovary during the follicular phase of the estrous cycle*
Authors: Cárdenas H. , Pope W.F. 
Published: August 2002

AbstractFollicle‐stimulating hormone (FSH) is an important regulator of follicular development. Some effects of FSH on ovarian follicles might be enhanced by androgens. The main objectives of the present study were to examine expression of the androgen receptor (AR) and FSH receptor (FSHR) in late developing follicles in pigs. Ovaries were collected from gilts on days 13, 15, 17, and 19 of the estrous cycle (day 0 = first day of estrus, n = 4 gilts/day), a period coincident with the follicular phase. One ovary was processed for immunohistochemistry (IHC) of AR. Samples of surface wall from the largest follicles (4–5 per gilt) were dissected from the other ovary, pooled and processed for determination of AR and FSHR mRNAs using reverse transcription‐polymerase chain reaction (RT‐PCR). Intense AR immunostaining was present in nuclei of granulosa cells of preantral and antral follicles. AR immunoreactivity was also present in the nuclei of oocytes. Weak staining for AR was observed in cells of the theca interna, ovarian surface epithelium, and in most cells of the ovarian stroma. Relative amounts of immunoreactive AR in granulosa cells of late developing follicles, or small antral follicles (< 2 mm), did not differ between days 13, 15, 17, and 19. However, amounts of AR in granulosa cells of small antral follicles was greater (P < 0.05) than in the largest follicles present in the same ovary. The relative amounts of AR mRNA in tissue from the largest follicles on days 13, 15, 17, and 19 did not differ; however, amounts of FSHR mRNA in the same follicles were not different between days 13, 15, and 17, but decreased (P < 0.05) by day 19. Results indicate that during the follicular phase in gilts, the AR protein is mainly present in granulosa cells. Relative amounts of AR protein in granulosa cells and mRNA in walls of late developing follicles did not significantly change from day 13 to 19; however, amounts of FSHR mRNA decreased in preovulatory follicles by day 19 of the estrous cycle. Mol. Reprod. Dev. 62: 92‐98, 2002. © 2002 Wiley‐Liss, Inc.
Localization of an activin/activin receptor system in the porcine ovary
Authors: Van den Hurk R. , van de Pavert S.A. 
Published: August 2002

AbstractThe aim of this study was to locate a possible activin/activin receptor system within porcine ovaries containing functional corpora lutea. In situ hybridization was used to assess the gene expression of βA‐ and βB‐activin subunits, and immunohistochemical studies were done to detect activin‐A protein and activin receptor type II. mRNA expression of the βA‐ and βB‐activin subunits was found in the granulosa from the unilaminar follicle stage onward, in the developing thecal layer of multilaminar and small antral follicles, in the theca interna of mid‐sized antral follicles, in corpora lutea, and in the ovarian surface epithelium. Immunoreactive activin A protein could be detected at the same ovarian sites, but in thecal tissue of small antral follicles only. This protein was also demonstrated at the peripheral zone of oocytes from multilaminar and antral follicles. A positive immunoreaction for activin receptor was found in granulosa cells from multilaminar and older follicles and in oocytes from the earliest stages of follicular development onward. In late multilaminar follicles and in antral follicles, the oolemma was stained. Except for small antral follicles, a positive activin receptor immunoreaction was absent in the follicular theca. Activin receptor immunoreaction was furthermore present in corpora lutea and in the ovarian surface epithelium. It is concluded that, within porcine ovaries containing functional corpora lutea, an activin/activin receptor system is present in all intact follicles, the corpora lutea and the surface epithelium. Within follicles, granulosa and theca cells are the main sites of activin synthesis, while oocytes and granulosa cells are the main activin binding sites. Mol. Reprod. Dev. 60: 463–471, 2001. © 2001 Wiley‐Liss, Inc.
Bovine oocytes treated prior to in vitro maturation with a combination of butyrolactone I and roscovitine at low doses maintain a normal developmental capacity
Authors: Ponderato Nunzia , Lagutina Irina , Crotti Gabriella , Turini Paola , Galli Cesare , Lazzari Giovanna 
Published: August 2002

AbstractButyrolactone I (BL‐I) and Roscovitine (ROS), two specific and potent inhibitors of M‐phase promoting factor (MPF) kinase activity, were used to block germinal vesicle breakdown (GVBD) of cattle oocytes. A concentration 6.25 μM BL‐I and 12.5 μM ROS blocked over 93.3 ± 2.5% of oocytes in germinal vesicle (GV) stage during a 24‐hr culture period. Following a second 24‐hr culture step in maturation medium (IVM) almost all (91.5 ± 3.0%) inhibited oocytes resumed meiosis and reached the metaphase II (MII) stage. The MII kinetics was different for inhibited and control oocytes. Fifty percent MII was reached at 13–14 hr in BL‐I + ROS treated oocytes, compared to 18 hr in control oocytes. Therefore, control oocytes were fertilised (IVF) after 22 hr IVM and inhibited oocytes after 16 or 22 hr IVM. After IVF, percentage of grade 1 freezable embryos on day 7 (D + 7) as well as percentage of blastocyst formation on D + 8 in the group of BL‐I + ROS treated oocytes fertilised after 16 hr IVM were higher (P < 0.05) compared with the other experimental group fertilised after 22 hr IVM but not different in comparison with the control. Survival to freezing and thawing of grade 1 embryos frozen on D + 7 was employed as viability criteria and was similar in all groups. Thus, the presence of BL‐I + ROS in the prematuration medium of bovine oocytes determines a reversible meiotic block, without compromising their subsequent developmental competence. Mol. Reprod. Dev. 60: 579–585, 2001. © 2001 Wiley‐Liss, Inc.
Fast MRI of RF heating via phase difference mapping
Authors: Shapiro Erik M. , Borthakur Arijitt , Shapiro Michael J. , Reddy Ravinder , Leigh John S. 
Published: August 2002

AbstractA method is presented for the rapid acquisition of temperature maps derived from phase difference maps. The temperature‐dependent chemical shift coefficients (TDCSCs) of various concentrations of aqueous cobalt and dysprosium‐based compounds were measured. The largest TDCSC calculated was for 100 mM DyEDTA, which had a TDCSC of –0.09 PPM/K; 160 mM CoCl2 had a TDCSC of –0.04 PPM/K. These temperature‐dependent chemical shifts (TDCSs) result in phase changes in the MR signal with changing temperature. Agarose phantoms were constructed with each paramagnetic metal. A fast gradient‐echo (FGRE) MR image was acquired to serve as the baseline image. A “test” MRI procedure was then performed on the phantom. Immediately afterwards, a second FGRE MR image was acquired, serving as the probing image. Proper image processing as a phase difference map between the probing image and the baseline image resulted in an image which quantitatively described the temperature increase of the phantom in response to a particular “test” imaging experiment. Applications of this technique in assessing the safety of pulse sequences and MR coils are discussed. Magn Reson Med 47:492–498, 2002. © 2002 Wiley‐Liss, Inc.
Abdominal imaging with a modular combination of spin and gradient echoes
Authors: Jakob P.M. , Hillenbrand Claudia M. , Kenn Werner , D. Hahn  , Haase A. 
Published: August 2002

AbstractMR‐CAT (combined acquisition technique), a modular hybrid imaging concept, was introduced recently. In this article it is demonstrated that the CAT principles can be applied to form a versatile combination of spin and gradient echoes for abdominal imaging. This CAT approach, which essentially integrates RARE and EPI modules in a sequential fashion, was used to implement a set of segmented and single‐shot RARE/EPI‐CAT imaging techniques. CAT was used in in vivo studies to perform high‐resolution abdominal imaging in five healthy subjects. The results demonstrate the feasibility of abdominal imaging using the proposed CAT approach and the potential of this technique to reduce imaging time while preserving image quality. Magn Reson Med 47:425–432, 2002. © 2002 Wiley‐Liss, Inc.
Proton magnetization transfer effect in rat liver lactate
Authors: Dresselaers Tom , Bergans Niki , Van Hecke Paul , Vanstapel Florent 
Published: August 2002

AbstractOff‐resonance lactate magnetization transfer (MT) experiments were performed on the in situ rat liver under perfused and ischemic conditions. A significant MT effect for lactate methyl protons was observed. The effect was larger for the ischemic condition than for the perfused condition, and was largest in the blood‐filled ischemic livers. The size of the motionally restricted lactate pool, determined using a two‐pool model fit, was estimated to be about 1% in perfused livers and about 1.8–2.5% after more than 1 hr of onset of ischemia, suggesting that lactate in liver is almost fully NMR‐visible. The MT data for both the perfused and the ischemic condition appeared to be better approximated when assuming a superLorentzian lineshape for the immobile pool rather than a Gaussian lineshape. Finally, the experiments demonstrated a coupling between the lactate methyl and water protons, which may be mediated by macromolecules. Magn Reson Med 47:880–887, 2002. © 2002 Wiley‐Liss, Inc.
1H NMR visible lipids are induced by phosphonium salts and 5‐fluorouracil in human breast cancer cells
Authors: Cooper Wendy A. , Bartier Wendy A. , Rideout Darryl C. , Delikatny Edward J. 
Published: August 2002

AbstractCationic lipophilic phosphonium salts (CLPS) selectively accumulate in the mitochondria of neoplastic cells and inhibit mitochondrial function. The effects of the CLPS p‐(triphenylphosphoniummethyl) benzaldehyde chloride (drug A), and [4‐(hydrazinocarboxy)‐1‐butyl] tris‐(4‐dimethylaminophenyl) phosphonium chloride (drug B), on human breast cells of differing biological properties were assessed using growth inhibition assays and 1H NMR. Drug A and, to a lesser extent, drug B demonstrated selective growth inhibition of the highly tumorigenic DU4475 breast carcinoma cell line compared to the transformed HBL‐100 human breast cell line. However, in contrast to previous studies using other cell lines, no synergistic activity was found when the drugs were used in combination. 1H NMR demonstrated significant increases in mobile lipid acyl chain resonances in both cell lines treated with cytotoxic doses (IC50, 48 h) of the drugs used either alone or in combination. Two‐dimensional NMR revealed accompanying decreases in phosphocholine/Lys levels in HBL‐100 cells treated with A, B, or a 1:1 combination A+B at the IC50, and in DU4475 cells treated with drug A (IC50). This was accompanied by significant increases in cho/Lys ratios with IC50 A or combination A+B treatment. Similar spectra were observed in cells treated with 5‐fluorouracil but not methotrexate, indicating that mobile lipid accumulation is a general but not universal response to cytotoxic insult. Magn Reson Med 45:1001–1010, 2001. © 2001 Wiley‐Liss, Inc.
Ghost artifact cancellation using phased array processing
Authors: Kellman Peter , McVeigh Elliot R. 
Published: August 2002

AbstractIn this article, a method for phased array combining is formulated which may be used to cancel ghosts caused by a variety of distortion mechanisms, including space variant distortions such as local flow or off‐resonance. This method is based on a constrained optimization, which optimizes SNR subject to the constraint of nulling ghost artifacts at known locations. The resultant technique is similar to the method known as sensitivity encoding (SENSE) used for accelerated imaging; however, in this formulation it is applied to full field‐of‐view (FOV) images. The method is applied to multishot EPI with noninterleaved phase encode acquisition. A number of benefits, as compared to the conventional interleaved approach, are reduced distortion due to off‐resonance, in‐plane flow, and EPI delay misalignment, as well as eliminating the need for echo‐shifting. Experimental results demonstrate the cancellation for both phantom as well as cardiac imaging examples. Magn Reson Med 46:335–343, 2001. Published 2001 Wiley‐Liss, Inc.
Improving relative anisotropy measurement using directional correlation of diffusion tensors
Authors: Sun Shu‐Wei , Song Sheng‐Kwei , Hong Chung‐Yi , Chu Woei C. , Chang Chen 
Published: August 2002

AbstractA method employing directional correlation of the diffusion tensor, directional‐correlation weighted relative anisotropy (DRA), was developed to improve the accuracy of estimated relative anisotropy (RA). The intravoxel directional correlation was established on the same voxel between two identically acquired diffusion tensor images, and the correlation coefficient derived from tensor dot product was employed as the weighting factor applied in the calculation of RA. The effect of noise influence was reduced since the random noise between repeated scans is not directionally correlated. The RA and the inter‐ and intravoxel DRA estimations were examined on rat brains in vivo. The background noise alters the direction of eigenvectors and the magnitude of eigenvalues. The dispersion angle between repeatedly obtained eigenvectors, representing the extent of directional alteration of eigenvectors, depends on the tissue anisotropy as well as the signal‐to‐noise ratio (SNR) of the source images. Current results demonstrate that the intravoxel DRA improves the accuracy of RA estimation, increases the relative contrast of gray and white matter, and avoids the partial volume effect commonly seen in the intervoxel operations. Magn Reson Med 46:1088–1092, 2001. © 2001 Wiley‐Liss, Inc.
A pharmacokinetic model for quantitative evaluation of spinal cord injury with dynamic contrast‐enhanced magnetic resonance imaging
Authors: Bilgen Mehmet , Narayana Ponnada A. 
Published: August 2002

AbstractA multicompartment pharmacokinetic model was proposed to quantitatively describe the distribution of the contrast agent gadopentetate‐dimeglumine (Gd) in an experimental spinal cord injury (SCI). Concentration of Gd was measured in different compartments with in vivo dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) in the acute phase of injury. The concentration data for each rat was fitted to the model to estimate transfer rates between different compartments. The results indicate: 1) lack of uptake of Gd in normal cord tissue, 2) rapid exchange of Gd between plasma and cerebrospinal fluid in both normal and injured cord tissues, and 3) slower uptake of Gd in injured cord. With this approach, it is possible to quantify the integrity of the blood–spinal cord barrier (BSCB) in vivo, evaluate the pathobiology of injured cord, assess the efficacy of interventions, and monitor the progression of injury with postinjury time. Magn Reson Med 46:1099–1106, 2001. © 2001 Wiley‐Liss, Inc.
Zero‐quantum filter offering single‐shot lipid suppression and simultaneous detection of lactate, choline, and creatine resonances
Authors: Star‐Lack J.M. , Spielman D.M. 
Published: August 2002

AbstractA zero‐quantum (ZQ) filter offering single‐shot lipid suppression and providing for simultaneous detection of the lactate methyl doublet (1.3 ppm) and nonoverlapping singlets including choline (Cho, 3.2 ppm) and creatine (Cr, 3.0 ppm) is described. Filtering is provided by soft mixing and reading pulses (RFmix, RFrd) that are selective for the lactate methine quartet (4.1 ppm), Cho, and Cr resonances but exclude the 1.3 ppm lactate component and overlapping lipids. Surrounding RFmix and RFrd are magnetic field gradient pulses of equal magnitude but opposite signs to enable the rephasing of the zero‐quantum lactate coherence and the creation of a stimulated echo for singlets within the pulse passbands. The sequence is designed to retain half the original lactate and singlet signal intensities. Theoretical predictions were confirmed experimentally at 1.5T using phantom acquisitions. The lipid suppression factor was measured to be over 103. Magn Reson Med 46:1233–1237, 2001. © 2001 Wiley‐Liss, Inc.
Projection reconstruction balanced fast field echo for interactive real‐time cardiac imaging
Authors: Schaeffter Tobias , Weiss Steffen , Eggers Holger , Rasche Volker 
Published: August 2002

AbstractA balanced fast field echo (FFE) sequence (also referred to as true fast imaging with steady precession (true FISP)), based on projection reconstruction (PR) is evaluated in combination with real‐time reconstruction and interactive scanning capabilities for cardiac function studies. Cardiac image sequences obtained with the balanced PR‐FFE method are compared with images obtained with a spin‐warp (2D Fourier transform (2DFT)) technique. In particular, the representation of motion artifacts in both techniques is investigated. Balanced PR‐FFE provides a similar contrast to spin‐warp‐related techniques, but is less sensitive to motion artifacts. The use of angular undersampling within balanced PR‐FFE is examined as a means to increase temporal resolution while causing only minor artifacts. Furthermore, a modification of the profile order allows the reconstruction of PR images at different spatial and temporal resolution levels from the same data. This study shows that balanced PR‐FFE is a robust tool for cardiac function studies. Magn Reson Med 46:1238–1241, 2001. © 2001 Wiley‐Liss, Inc.