bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alternative splicing of fibronectin mRNAs in chondrosarcoma cells: Role of far upstream intron sequences
Authors: Flanagan Matthew , Liang Hongyan , Norton Pamela A. 
Published: October 2003

AbstractThe fibronectin (FN) gene encodes multiple mRNAs through the process of alternative splicing, and production of certain isoforms is characteristic of a given cell type. Chondrocytes produce FNs that completely lack alternative exon EIIIA, and loss of inclusion of the exon is tightly linked to chondrogenic condensation of mesenchymal cells. The inclusion of a second exon, EIIIB, is high in embryonic cartilage, but declines with age. Multiple exons are omitted to produce the (V + C)‐form that is highly specific for cartilage and chondrocytes. A rat chondrosarcoma cell line, RCS, was identified that preserves key features of the cartilage‐specific splicing phenotype. RCS cells, which exclude exon EIIIA, and HeLa cells, which include exon EIIIA similar to mesenchymal cells, were used to assess the contribution of intron sequences flanking exon EIIIA to splicing regulation. Deletion of most of the intron downstream of the exon had little effect on splicing in either cell type. However, deletions within upstream intron 32‐A reduced inclusion of the alternative exon in both cell types. The sequences involved lie more than 200 nucleotides away from the exon, but could not be localized to a single region by deletion mapping. These intronic sequences contribute to the efficiency of exon EIIIA recognition, but not to cell‐type specific regulation. The normally inhibitory factor polypyrimidine tract binding protein promotes exon EIIIA inclusion in a manner that is partially dependent on the regulatory sequences within intron 32‐A. © 2003 Wiley‐Liss, Inc.
Secreted apolipoprotein E reduces macrophage‐mediated LDL oxidation in an isoform‐dependent way
Authors: Mabile Laurence , Lefebvre Chantal , Lavigne Jacques , Boulet Lucie , Davignon Jean , Lussier‐Cacan Suzanne , Bernier Lise 
Published: October 2003

AbstractAs an inflammatory cell, the macrophage produces various oxidizing agents, such as free radical species. These can modify LDL as a secondary effect and doing so may favor atherogenic processes. Any molecule able to counteract these reactions would be of much benefit, especially if secreted by the macrophage itself at the lesion site. Such is the case for apolipoprotein E (apoE), which has been shown to exert antioxidant properties in some studies, mostly in relation to Alzheimer's disease. In this study, we assessed the antioxidant potential of the various isoforms of apoE (E2, E3, and E4) using a metal‐induced LDL oxidation system with exogenous recombinant apoE and an in vitro model of macrophage‐mediated LDL oxidation. We found that all three isoforms had an antioxidant capacity. However, whereas apoE2 was the most protective isoform in the cell‐free system, the opposite was observed in apoE‐transfected J774 macrophages. In the latter model, cellular cholesterol efflux was found to be more important with apoE2, possibly explaining the larger quantity of oxidative indices observed in the medium. It is proposed that the antioxidant property of apoE results from a balance between direct apoE antioxidant capacities, such as the ability to trap free radicals, and potentially pro‐oxidative indirect events associated with cholesterol efflux from cells. Our observations add to the therapeutic potential of apoE. However, they also suggest the need for more experiments in order to achieve careful selection of the apoE isoform to be targeted, especially in the perspective of apoE transgene use. © 2003 Wiley‐Liss, Inc.
Temperature interpolation at a large scale: test on a small area in Svalbard
Authors: Joly D. , Nilsen L. , Fury R. , Elvebakk A. , Brossard T. 
Published: October 2003

AbstractA major environmental concern regarding the Arctic is how global change effects can influence vegetation and ecosystems. The amount of summer warmth is the single most important variable for biological processes in the Arctic, and the one that is most likely to be affected by climate change. A major task is to establish how temperature conditions are modified at a very high spatial resolution.In order to build up scenarios that are as relevant as possible concerning vegetation development, the key point is to know how the spatial distribution of temperature varies and can be related to different environment factors at different spatial scales. A method is suggested for modelling the temperature distribution at a high resolution (2 × 2 m2) and with high accuracy. In step one, a polynomial equation is established for modelling the distribution of temperature values measured in the field at low spatial resolution (1 × 1 km2), with latitude and longitude defining the general trend surface of the temperature distribution. In step two, residue values from the previous step are explained by environment factors stored as numerical information layers in a geographical information system. These environmental data are derived from a high‐resolution digital elevation model and from a digitized infrared aerial photograph. Finally, the combination of these kilometric and micro‐scale models make it possible to restore the thermic field of the study area and to represent it through different maps at a very fine‐grained resolution. The method is tested on two glacier forefields in Svalbard, covering an area of 8 km2. Copyright © 2003 Royal Meteorological Society
Thermal field over Tibetan Plateau and Indian summer monsoon rainfall
Authors: Bansod Sanjay D. , Yin Zhi‐Yong , Lin Zhenyao , Zhang Xueqin 
Published: October 2003

AbstractThe interannual variability of the temperature anomalies over the Tibetan Plateau (25–45 °N, 75–105 °E) is examined in relation to the Indian summer monsoon rainfall (ISMR: June to September total rainfall). For this purpose, the temperature anomaly data of the central‐eastern Tibetan Plateau is divided into three regions using principal component analysis and the ISMR data for the period 1957–89 have been used. It is found that the January temperature anomaly of Region 2 has a significant negative relationship (r = −0.67) with the ISMR of the subsequent season. This region is located over the northeastern part of the Tibetan Plateau, mostly in Qinghai province, including the Bayan Harr Mountain range and the Qaidam Basin. This relationship is consistent and robust during the period of analysis and can be used to predict the strength of the Indian summer monsoon in the subsequent season. It was found that the January temperature anomaly in this region was associated with a persistent winter circulation pattern over the Eurasian continent during January through to March. Finally, the variation patterns of the temperature anomalies in all three regions over the central‐eastern Tibetan Plateau during extreme years of the ISMR are examined. It is concluded that the January temperature anomaly over the northeastern Tibetan Plateau can be useful in forecasting the drought and flood conditions over India, especially in predicting the monsoon rainfall over the areas lying along the monsoon trough. Copyright © 2003 Royal Meteorological Society
Relations between sea‐surface temperature and crop yields in Argentina
Authors: Travasso M. I. , Magrin G. O. , Rodríguez G. R. 
Published: October 2003

AbstractThe El Niño–southern oscillation phenomenon (ENSO) is one of the principal sources of interannual climatic variability. In Argentina, the ENSO signal is evident both in climate and crop yields. As ENSO phases (El Niño, La Niña, Neutral) can actually be predicted several months before their occurrence, the use of ENSO‐based climate forecasts as tools to assist farmers in decision making has recently been proposed. However, the use of ENSO‐phases could be insufficient for planning in the agricultural sector due to the signal interannual intra‐phase variability. Moreover, the observed spatial variability in the ENSO signal suggests the existence of other factors that influence the local climate and crop responses in the region. Looking for alternative indicators of climate variability other than ENSO phases, monthly sea‐surface temperature (SST) anomalies from the equatorial Pacific and the South Atlantic Oceans were related to maize and wheat yield anomalies in the main crop‐producing zone of the Pampas region. In general, yield anomalies were better correlated with SST anomalies occurring in the months prior to sowing. This indicator could be a useful tool to ascertain what range of yields could be expected with sufficient anticipation so as to modify crop management decisions. Copyright © 2003 Royal Meteorological Society
The teleconnections between the extreme phases of the southern oscillation and precipitation patterns over Turkey
Authors: Çaǧatay Karabörk M. , Kahya Ercan 
Published: October 2003

AbstractClimatic links between monthly precipitation in Turkey and the El Niño and La Niña events using the empirical methodology of Ropelewski and Halpert are investigated. Coherent and significant precipitation responses to both the extreme phases of the southern oscillation (SO) are found in two core regions, namely western Anatolia (WA) and eastern Anatolia (EA). The geographical extent of the two regions, together with a defined signal season for each tropical event, are identified. For WA, the April–July wet period during El Niño events is the season when the teleconnection is strong and consistent. For EA, the February–June wet period during El Niño events is found to be the signal season having high rates of coherence and consistency. The occurrence of the signal season (the dry period of April–October) during La Niña events appears to be less significant in EA according to the hypergeometric model. Moreover, the annual cycle analysis implies somewhat of a modulation of regional precipitation in the WA and EA regions during the relevant signal season. From other perspectives, correlation results of seasonal precipitation and seasonal SO index values confirm the implied teleconnections, and the powers of line spectra corresponding to the El Niño occurrences supply some indications. The final aim of this work is to show some guidance for quantification of the SO‐related precipitation teleconnections for the core regions by examining shifts in precipitation amounts at various percentiles as a function of the SO extremes. Overall, the results of this investigation are in good agreement with previous relevant studies (especially global‐scale type) that try to understand complex global circulation dynamics. In conclusion, mid‐latitude precipitation responses to the extreme phases of the SO are detectable in the climate of Turkey. Copyright © 2003 Royal Meteorological Society
Carbon dioxide and water vapour flux densities over a grassland area in the Netherlands
Authors: Jacobs Adrie F. G. , Heusinkveld Bert G. , Holtslag Albert A. M. 
Published: October 2003

AbstractMeasurements of carbon dioxide and water vapour flux densities were carried out for a grassland area in the centre of the Netherlands during a 12 month continuous experiment using the eddy‐covariance technique. Lolium perenne and Poa trivialis mainly dominated the vegetation of the area. The leaf area index (LAI) of the grassland varied between 2.5 and 3.4, depending on the mowing scheme at the site. Fluxes are also calculated by using a canopy model in which the canopy resistance is related to the assimilation rate (A–gs model). The calculated evapotranspiration fluxes agree within 7% of the measured fluxes (R2 = 0.93;SEE = 23 W m−2). The calculated net carbon dioxide fluxes agree within 12% of the measured fluxes (R2 = 0.79;SEE = 0.16 mg m−2s−1). The net carbon dioxide fluxes consist of two opposite components: the uptake via assimilation and release via soil and plant respiration. It appears that nearly the whole year round the assimilation term dominates, which means an accumulation of carbon dioxide if no other exchange processes are present. For 2002 a net carbon uptake was found of 6.8 tonnes ha−1. Copyright © 2003 Royal Meteorological Society
Comparative analysis of spatial and seasonal variability: Austrian precipitation during the 20th century
Authors: Matulla Christoph , Penlap Edouard K. , Haas Patrick , Formayer Herbert 
Published: October 2003

AbstractThe purpose of this investigation is to demonstrate the usability of objective methods to study the variability of precipitation and hence to contribute to a better understanding of spatial and seasonal variability of Austria's precipitation climate during the 20th century.This will be achieved by regionalizing the intra‐annual variability of seasonal precipitation distributions during three non‐overlapping 33 year samples (1901–33, 1934–66, 1967–99). Monthly precipitation totals were extracted at 31 Austrian stations from a homogenized long‐term climate dataset provided by the Austrian weather service. Three statistical techniques, namely cluster analysis (CLA), rotated empirical orthogonal functions (REOFs) and an unsupervised learning procedure of artificial neural networks (ANNs), were utilized to find homogeneous precipitation regions.The results of summer (June, July, August (JJA)) and winter (December, January, February (DJF)) seasons are presented. The resulting homogeneous precipitation regions depend on season, period and method in this order. Hence, differences introduced by using different methods are small compared with those inferred by investigating different episodes and especially with those related to the seasons.During winter, three homogeneous precipitation regions are found, independent from the period considered. These regions can be assigned to different airflows dominating Austria's climate and triggering precipitation events during the cold season. The situation during summer is more complicated. Thus, at least four clusters are necessary to record the circumstances, which are caused by spatially inhomogeneous convective events such as thunderstorms. Copyright © 2003 Royal Meteorological Society
Winter snow anomaly and atmospheric circulation in Mongolia
Authors: Morinaga Yuki , Tian Shao‐Fen , Shinoda Masato 
Published: October 2003

AbstractAn observational study was conducted of winter snow anomaly in Mongolia and the associated atmospheric circulation. Monthly data of snow depth and temperature at 23 Mongolian stations from 1940 to 1992 were used for a statistical analysis. The Mongolian snow amount is fairly large in the northern mountainous regions and decreases to the south. On average, there is a substantial seasonal increase in snow depth during November and December. The deepest snow occurs in January, with an average depth of 3.4 cm averaged for all 23 stations. The correlation coefficients for November and December between the snow depth and temperature are significant and negative over wide areas.A principal component analysis was applied to interannual anomalies of January snow depth. The first mode (PC1) reveals widespread loadings of the same sign, and the second mode (PC2) shows a northeast–southwest dipole pattern. A correlation analysis was employed to examine relationships between PC1, PC2 and the preceding atmospheric circulation modes derived from a principal component analysis of the Northern Hemisphere 500 hPa geopotential heights. The PC1 time series for January is highly correlated with the North Atlantic oscillation for November, and the PC2 time series is significantly correlated with the Eurasian pattern for December. These relationships will provide a potential basis for long‐range forecasts of mid‐winter anomalous snow that leads to a significant loss of livestock (so‐called white dzud) in Mongolia. Copyright © 2003 Royal Meteorological Society
Comparative genomic hybridization of estrogen‐induced ectopic uterine‐like stem cell neoplasms in the hamster kidney: Nonrandom chromosomal alterations
Authors: Papa Dan , Li Sara Antonia , Li Jonathan J. 
Published: October 2003

AbstractKaryotype and comparative genomic hybridization (CGH) analyses were performed to identify nonrandom/consistent chromosomal alterations in solely estrogen (E)‐induced primary ectopic uterine‐like stem cell tumors in the kidney (EULTK) of the Syrian hamster, using a criterion of ≥20% frequency for nonrandom occurrence. Employing this criterion, EULTK karyotype analysis showed consistent gains in chromosomes 3, 6, 11, 14, 16, 20, and 21. Consistent trisomies were seen in all of these nonrandomly gained chromosomes. Only chromosomes 3 and 6 exhibited appreciable tetrasomies. Chromosome losses were observed consistently in chromosomes 7, 12, 17, and 19. Employing the same criterion, CGH analysis of primary EULTKs showed nonrandom amplified sequences at 1pa1–a4, 2cen–pter, 3pa1–a4, 6qb2–b4, 20qa1–a4, 21qa1–a2, Xqa3–qter and regional consistent losses at 1qc1‐qter, 2qb1–c1, 3qa2–a7, 11qb5‐qter, 15qa2–a5, 18qa2–a4, and 21pa. Moreover, 88% of the EULTKs examined exhibited amplification of the 6qb2–b4 region, where c‐myc resides. The data presented lend credence to the supposition that chromosomal instability (CIN) is elicited by the upstream overexpression and subsequent amplification of c‐myc by Es in multipotential interstitial uterine stem cells present in the kidney, thus leading to neoplastic development. © 2003 Wiley‐Liss, Inc.
Cell growth inhibition by all‐trans retinoic acid in SKBR‐3 breast cancer cells: Involvement of protein kinase Cα and extracellular signal‐regulated kinase mitogen‐activated protein kinase
Authors: Nakagawa Shino , Fujii Teruhiko , Yokoyama Goro , Kazanietz Marcelo G. , Yamana Hideaki , Shirouzu Kazuo 
Published: October 2003

AbstractAll‐trans retinoic acid (ATRA), a synthetic derivative of vitamin A, inhibits the growth of breast cancer cells. To elucidate the mechanism by which ATRA causes cell growth inhibition, we examined changes in cell cycle and intracellular signaling pathways, focusing on protein kinase C (PKC) and mitogen‐activated protein kinase (MAPK). Using the estrogen receptor‐negative, retinoid receptor–positive breast cancer cell line SKRB‐3, we found that treatment with ATRA significantly decreased the expression of PKCα, as well as reducing ERK MAPK phosphorylation. ATRA treatment leads to dephosphorylation of Rb, and consequently to G1 arrest. Marked changes in the expression of cyclins (particularly cyclins A and E) were observed in SKBR‐3 cells treated with ATRA. Using a series of pharmacological and molecular approaches, we found evidence that ATRA‐induced SKBR‐3 cell growth inhibition involves the deregulation of the PKCα‐MAPK pathway. These data suggest that retinoids interfered with signal transduction pathways that are crucial for cell cycle progression, and highlight the complexities of the biological effects of retinoid derivatives. © 2003 Wiley‐Liss, Inc.
Reduced transcription of the RB2/p130 gene in human lung cancer
Authors: Xue Jun Hu , Gemma Akihiko , Hosoya Yoko , Matsuda Kuniko , Nara Michiya , Hosomi Yukio , Okano Tetsuya , Kurimoto Futoshi , Seike Masahiro , Takenaka Kiyoshi , Yoshimura Akinobu , Toyota Minoru , Kudoh Shoji 
Published: October 2003

AbstractReduced expression of the retinoblastoma gene (RB)2/p130 protein, as well as mutation of exons 19, 20, 21, and 22 of the same gene, has been reported in primary lung cancer. However, it has been suggested by other investigators that mutational inactivation and loss of the RB2/p130 gene and protein, respectively, are rare events in lung cancer. In order to determine the contribution and mechanisms of RB2/p130 gene inactivation to lung cancer development and progression, we quantified RB2/p130 mRNA expression levels in a range of human lung cancer cell lines (n = 13) by real‐time reverse transcription (RT)‐polymerase chain reaction (PCR) analysis. In comparison to normal lung tissue, reduced transcription of the RB2/p130 gene was found in all small cell lung cancer cell lines examined, along with six out of the eight nonsmall cell lung cancers tested, most of which had inactivation of RB/p16 pathway. On the basis of Western blot analysis, the expression of RB2/p130 protein was consistent with RNA expression levels in all lung cancer cell lines examined. In addition, the mutational status of the RB2/p130 gene (specifically, exons 19, 20, 21, and 22) was determined in 30 primary lung cancers (from patients with distant metastasis) and 30 lung cancer cell lines by PCR‐single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing. There was no evidence of somatic mutations within the RB2/p130 gene in the 60 lung cancer samples (both cell lines and tumors) assessed, including the 11 lung cancer cell lines that displayed reduced expression of the gene. Furthermore, hypermethylation of the RB2/p130 promoter was not found in any of the above‐mentioned 11 cell lines, as determined by a DNA methylation assay, combined bisulfite restriction analysis (COBRA). The results of the present study suggest that the reduced RB2/p130 expression seen in lung cancer may be in part transcriptionally mediated, albeit not likely via a mechanism involving hypermethylation of the RB2/p130 promoter. The observed reduction in RB2/p130 gene expression may be due to histone deacetylation, altered mRNA stability, and/or other forms of transcriptional regulation. © 2003 Wiley‐Liss, Inc.
Ultimate intrinsic signal‐to‐noise ratio for parallel MRI: Electromagnetic field considerations
Authors: Ohliger Michael A. , Grant Aaron K. , Sodickson Daniel K. 
Published: October 2003

AbstractA method is described for establishing an upper bound on the spatial encoding capabilities of coil arrays in parallel MRI. Ultimate intrinsic signal‐to‐noise ratio (SNR), independent of any particular conductor arrangement, is calculated by expressing arbitrary coil sensitivities in terms of a complete set of basis functions that satisfy Maxwell's equations within the sample and performing parallel imaging reconstructions using these basis functions. The dependence of the ultimate intrinsic SNR on a variety of experimental conditions is explored and a physically intuitive explanation for the observed behavior is provided based on a comparison between the electromagnetic wavelength and the distance between aliasing points. Imaging at high field strength, with correspondingly short wavelength, is shown to offer advantages for parallel imaging beyond those already expected due to the larger available spin polarization. One‐dimensional undersampling of k‐space yields a steep drop in attainable SNR for more than a 5‐fold reduction of scan time, while 2D undersampling permits access to much higher degrees of acceleration. Increased tissue conductivity decreases baseline SNR, but improves parallel imaging performance. A procedure is also provided for generating the optimal coil sensitivity pattern for a given acceleration, which will serve as a useful guide for future coil designs. Magn Reson Med 50:1018–1030, 2003. © 2003 Wiley‐Liss, Inc.