bluuebunny/crossref_metadata_2025_split huggingface dataset:
Double‐cleavage production of the CTL epitope by proteasomes and PA28: role of the flanking region
Authors: Shimbara Naoki , Nakajima Hiroto , Tanahashi Nobuyuki , Ogawa Kiyoko , Niwa Shin‐ichiro , Uenaka Akiko , Nakayama Eiichi , Tanaka Keiji 
Published: November 2003

Background:Proteasomes are known to produce major histocompatibility complex (MHC) class I ligands from endogenous antigens, and the γ‐interferon‐inducible proteasome activator PA28 has been thought to play an important role in the generation of immunodominant MHC ligands by proteasomes. Several attempts have been made to show that proteasomes have the ability to yield cytotoxic T lymphocyte (CTL) epitopes effectively from model polypeptides derived from viral and intracellular proteins in vitro, but their antigen processing mechanism is poorly understood.Results:Proteasomes produce the tumour rejection antigen precursor peptide pRL1b (SIIPGLPLSL), but not pRL1a (IPGLPLSL), bound to the H‐2Ld molecule, from synthetic peptides covering the CTL epitope. This double cleavage production of pRL1b by proteasomes seemed to depend on the length of the flanking regions adjacent to either end of the CTL epitope, in which their successive deletions caused the almost complete prevention of pRL1b excision. The newly identified PA28 collaborates with proteasomes for efficient production of pRL1b, by promoting not only single cleavage of all susceptible peptides, but also dual cleavage in some peptides harboring certain characteristic lengths.Conclusion:The flanking regions outside pRL1b of suitable length appear to be essential for the correct CTL epitope production, possibly functioning as anchors to trap target peptides for proteasomal degradation. We propose a novel mechanism for dual‐cleavage excision of immunodominant epitopes by proteasomes and PA28.
Essential role for ERK2 mitogen‐activated protein kinase in placental development
Authors: Hatano Naoya , Mori Yoshiko , Oh‐hora Masatsugu , Kosugi Atsushi , Fujikawa Takahiko , Nakai Naoya , Niwa Hitoshi , Miyazaki Jun–ichi , Hamaoka Toshiyuki , Ogata Masato 
Published: November 2003

AbstractBackground:  Extracellular signal‐regulated kinase 2 (ERK2) has been implicated in cell proliferation, differentiation, and survival. However, its role in vivo remains to be determined.Results:  Here we show that the targeted disruption of the mouse ERK2 gene results in embryonic lethality by E11.5 and severe abnormality of the placenta. In these animals, the labyrinthine layer of the placenta is very thin and few foetal blood vessels are observed. ERK2 mutants can be rescued by the transgenic expression of ERK2, demonstrating that these abnormalities are caused by ERK2‐deficiency. Although ERK2‐deficient fetuses are much smaller than wild‐type littermates, this seems to be secondary to malfunction of the placenta. When the placental defect is rescued by tetraploid‐aggregation, ERK2‐deficient foetuses grow as well as littermate controls.Conclusion:  These observations indicate that ERK2 is essential for placental development and suggest that ERK2 in the trophoblast compartment may be indispensable for the vascularization of the labyrinth.
Cks1 is degraded via the ubiquitin‐proteasome pathway in a cell cycle‐dependent manner
Authors: Hattori Takayuki , Kitagawa Kyoko , Uchida Chiharu , Oda Toshiaki , Kitagawa Masatoshi 
Published: November 2003

AbstractBackground:  Recent work has demonstrated the role of cdc kinase subunit 1 (Cks1) in the ubiquitin‐proteasome dependent degradation of CDK inhibitor p27Kip1 protein as an essential cofactor for SCFSkp2 ubiquitin ligase. Although over‐expression of Cks1 protein as well as it of Skp2 might be associated with tumour progression via p27Kip1 protein degradation, it is unknown how the cellular level of Cks1 is regulated.Results:  Here we show that Cks1 protein is degraded via the ubiquitin‐proteasome pathway. Degradation of Cks1 protein was markedly inhibited by proteasome inhibitors. In addition, Cks1 protein was modified with polyubiquitin chains both in vivo and in vitro. Furthermore, we found that degradation of Cks1 protein via the ubiquitin‐proteasome pathway was facilitated in M phase during the cell cycle.Conclusion:  These observations suggest that the level of expression of Cks1 protein is regulated at not only the transcriptional level but also the post‐translational level via the ubiquitin‐proteasome pathway in a cell‐cycle‐dependent manner.
Over‐expression of a novel nuclear interactor of Suppressor of fused, the Drosophila myelodysplasia/myeloid leukaemia factor, induces abnormal morphogenesis associated with increased apoptosis and DNA synthesis
Authors: Fouix Sylvaine , Martin‐Lannerée Séverine , Sanial Matthieu , Morla Luciana , Lamour‐Isnard Claudie , Plessis Anne 
Published: November 2003

AbstractBackground:  In Drosophila and vertebrates, suppressor of fused (Su(fu)) proteins act as negative regulators of the Gli/Ci transcription factors, which mediate the transcriptional effects of Hh signalling.Results:  We sought for novel partners of Su(fu) in fly using the two‐hybrid method. Most of the Su(fu) interactors thus identified are (or are likely to be) able to enter the nucleus. We focused on one of these putative partners, dMLF, which resembles vertebrate myelodysplasia/myeloid leukaemia factors 1 and 2. We demonstrate that dMLF binds specifically to Su(fu) in vitro and in vivo. Using a novel anti‐dMLF antibody, we showed, that dMLF is a nuclear, chromosome‐associated protein. We over‐expressed a dMLF transgene in fly using an inducible expression system and showed that dMLF over‐expression disrupts normal development, leading to either a lethal phenotype or adult structural defects associated with apoptosis and increased DNA synthesis. Furthermore, the dMLF‐induced eye phenotype is enhanced by the loss of Su(fu) function, suggesting a genetic interaction between Su(fu) and dMLF.Conclusion:  We propose that dSu(fu) and dMLF act together at the transcriptional level to coordinate patterning and proliferation during development.
Elimination of source‐generated noise from correlated vibroseis data (the ‘ghost‐sweep’ problem)
Authors: Polom Ulrich 
Published: November 2003

The most common noise‐reduction methods employed in the vibroseis technique (e.g. spike and burst reduction, vertical stacking) are applied in the field to reduce noise at a very early stage. In addition, vibrator phase control systems prevent signal distortions produced by non‐linearity of the source itself. However, the success of these automatic correction methods depends on parameter justification by the operator and the actual characteristics of the distorting noise. More specific noise‐reduction methods (e.g. Combisweep (Trade mark of Geco‐Prakla), elimination of harmonics) increase production costs or need uncorrelated data for the correction process. Because the field data are usually correlated and vertically stacked in the field to minimize logistical and processing costs, it is not possible to make subsequent parameter corrections to optimize the noise reduction after correlation and vertical stacking of a production record.The noise‐reduction method described here uses the final recorded, correlated and stacked vibroseis field data. This method eliminates signal artifacts caused e.g. by incorrect vibroseis source signals being used in parameter estimation when a frequency–time analysis is combined with a standard convolution process. Depending on the nature of the distortions, a synthetically generated, nearly recursive noise‐separation operator compresses the noise artifact in time using a trace‐by‐trace filter. After elimination of this compressed noise, re‐application of the separation operator leads to a noise‐corrected replacement of the input data. The method is applied to a synthetic data set and to a real vibroseis field record from deep seismic sounding, with good results.
Modelling the 2D terrain effect on MT by the boundary‐element method
Authors: Xu Shi‐zhe , Zhou Hui 
Published: November 2003

The boundary‐element method is used to model the 2D terrain effect on the magnetotelluric (MT) field. Firstly, the boundary‐value problem of a 2D magnetotelluric field is transformed into an integral equation problem by using Green's theorem. Then the boundary‐element method is used to solve the integral equation and to obtain the MT field and its normal derivative on the terrain. From these values, the apparent resistivity can be calculated. Compared with the finite‐element method, the boundary‐element method is simpler in element division and the initial data preparation. The configuration of a terrain divided by the boundary‐element method is more consistent with the practical terrain. The method proposed in this paper can be run on a microcomputer, so that it can be used in the field.
Growth response of Trifolium repens L. and Lolium perenne L. as monocultures and bi‐species mixture to free air CO2 enrichment and management
Authors: HEBEISEN THOMAS , LÜSCHER ANDREAS , ZANETTI SILVIA , FISCHER BERNT , HARTWIG UELI , FREHNER MARCO , HENDREY GEORGE , BLUM HERBERT , NÖSBERGER* JOSEF 
Published: November 2003

Trifolium repens L. and Lolium perenne L. were grown in monocultures and bi‐species mixture in a Free Air Carbon Dioxide Enrichment (FACE) experiment at elevated (60 Pa) and ambient (35 Pa) CO2 partial pressure (pCO2) for three years. The effects of defoliation frequencies (4 and 7 cuts in 1993; 4 and 8 cuts in 1994/95) and nitrogen fertilization (10 and 42 g m–2 y–1 N in 1993; 14 and 56 g m–2 y–1 N in 1994/95) on the growth response to pCO2 were investigated.There were significant interspecific differences in the CO2 responses during the first two years, while in the third growing season, these interspecific differences disappeared. Yield of T. repens in monocultures increased in the first two years by 20% when grown at elevated pCO2. This CO2 response was independent of defoliation frequency and nitrogen fertilization. In the third year, the CO2 response of T. repens declined to 11%. In contrast, yield of L. perenne monocultures increased by only 7% on average over three years at elevated pCO2. The yield response of L. perenne to CO2 changed according to defoliation frequency and nitrogen fertilization, mainly in the second and third year. The ratio of root/yield of L. perenne increased under elevated pCO2, low N fertilizer rate, and frequent defoliation, but it remained unchanged in T. repens. We suggest that the more abundant root growth of L. perenne was related to increased N limitation under elevated pCO2.The consequence of these interspecific differences in the CO2 response was a higher proportion of T. repens in the mixed swards at elevated pCO2. This was evident in all combinations of defoliation and nitrogen treatments. However, the proportion of the species was more strongly affected by N fertilization and defoliation frequency than by elevated pCO2. Based on these results, we conclude that the species proportion in managed grassland may change as the CO2 concentration increases. However, an adapted management could, at least partially, counteract such CO2 induced changes in the proportion of the species. Since the availability of mineral N in the soil may be important for the species’ responses to elevated pCO2, more long‐term studies, particularly of processes in the soil, are required to predict the entire ecosystem response.
Effects of temperature elevation on the population dynamics of the upland heather psyllid Strophingia ericae (Curtis) (Homoptera: Psylloidea)
Authors: MILES J.E. , BALE J.S. , HODKINSON I.D. 
Published: November 2003

1 Cloches permeable to gas and water were used to simulate the effect of climate warming on upland populations of the heather psyllid Strophingia ericae at Moor House National Nature Reserve in the North Pennines, UK.2 The cloches produced an average warming of about 1 °C in the heather canopy over a period of one year.3 The density of S. ericae increased markedly in cloches within a few months of erection.4 Species composition and numbers of potential predators were similar inside cloches and in control plots.5 In the two year life‐cycle of S. ericae, the warming effect advanced the phenology from the second to third instar in the first winter, but in the second winter, fifth instar nymphs did not moult prematurely to adult.6 The density of S. ericae was higher on Calluna vulgaris at its boundary with Juncus squarrosus than in the pure C. vulgaris sward (in both cloched and control plots).
Short‐term decomposition of litter produced by plants grown in ambient and elevated atmospheric CO2 concentrations
Authors: BALL S. , DRAKE BERT 
Published: November 2003

The effects of elevated atmospheric CO2 (ambient + 340 μmol mol–1) on above‐ground litter decomposition were investigated over a 6‐week period using a field‐based mesocosm system. Soil respiratory activity in mesocosms incubated in ambient and elevated atmospheric CO2 concentrations were not significantly different (t‐test, P > 0.05) indicating that there were no direct effects of elevated atmospheric CO2 on litter decomposition.A study of the indirect effects of CO2 on soil respiration showed that soil mesocosms to which naturally senescent plant litter had been added (0.5% w/w) from the C3 sedge Scirpus olneyi grown in elevated atmospheric CO2 was reduced by an average of 17% throughout the study when compared to soil mesocosms to which litter from Scirpus olneyi grown in ambient conditions had been added. In contrast, similar experiments using senescent material from the C4 grass Spartina patens showed no difference in soil respiration rates between mesocosms to which litter from plants grown in elevated or ambient CO2 conditions had been added.Analysis of the C:N ratio and lignin content of the senescent material showed that, while the C:N ratio and lignin content of the Spartina patens litter did not vary with atmospheric CO2 conditions, the C:N ratio (but not the lignin content) of the litter from Scirpus olneyi was significantly greater (t‐test;P < 0.05) when derived from plants grown under elevated CO2 (105:1 compared to 86:1 for litter derived from Scirpus olneyi grown under ambient conditions). The results suggest that the increased C:N ratio of the litter from the C3 plant Scirpus olneyi grown under elevated CO2 led to the lower rates of biodegradation observed as reduced soil respiration in the mesocosms. Further long‐term experiments are now required to determine the effects of elevated CO2 on C partitioning in terrestrial ecosystems.
Carbon balance and water use efficiency of frequently cut Lolium perenne L. swards at elevated carbon dioxide
Authors: SCHAPENDONK A.H.C.M. , DIJKSTRA P. , GROENWOLD J. , POT C.S. , VAN DE GEIJN S.C. 
Published: November 2003

The impact of doubled atmospheric [CO2] on the carbon balance of regularly cut Lolium perenne L. swards was studied for two years under semi‐field conditions in the Wageningen Rhizolab. CO2 and H2O vapour exchange rates of the swards were measured continuously for two years in transparent enclosures. The light utilization efficiencies of the swards ranged between 1.5 g CO2 MJ–1 global radiation (high light, ambient [CO2]) and 2.8 g CO2 MJ–1 (low light, doubled [CO2]). The above‐ground net primary productivity (NPP) in the enclosures was greater by 29% in 1994 and 43% in 1995 in the doubled [CO2] treatments, but only 20% and 25% more carbon was recovered in the periodical cuts. Thus, NPP increased significantly more than did the harvested above‐ground biomass. The positive [CO2] effect on net carbon assimilation is therefore associated with a preferential allocation of extra carbon to the roots and soil.In addition to higher canopy photosynthesis and leaf elongation rates, a small part of the positive [CO2] effects on NPP could be attributed to a decrease of the specific respiration of the shoots. On a canopy basis however, respiration was equal or slightly higher at doubled [CO2] due to the higher amount of standing biomass.Comparison of NPP and carbon recovered in different harvests showed that allocation to roots and soil was highest in spring, it was low in early summer and increased again in late summer and autumn.The total gross amount of carbon partitioned to the roots and soil during the two year period was 57% more at doubled [CO2]. The total amount of carbon that was sequestered in the soil after subtraction of the respiratory losses was 458 g m–2 and 779 g m–2 in the ambient and doubled [CO2] treatments, respectively.The average water use efficiency (WUE) of the swards was increased by a factor 1.5 at doubled [CO2]. Both WUE and its positive interaction with [CO2] varied between years and were positively correlated with global irradiance. At doubled [CO2], the higher WUE was fully compensated for by a higher leaf area index. Therefore, total transpiration on a canopy basis was equal for the ambient and the doubled [CO2] concentrations in both years.
Cervical conservation: the future of hysterectomy?
Authors: Brown R. , Erian J. 
Published: November 2003

Objective There has been much debate about the place of subtotal hysterectomy in gynaecological practice. With the more widespread introduction of the laparoscopic approach to cervical conservation, this issue has once again been brought into prime focus. We have reviewed the currently available literature in an attempt to present a balanced summary of the evidence encompassing both laparoscopic and conventional subtotal hysterectomy.
Method Papers were identified using Current Contents (clinical medicine) and the Index Medicus (Medline). Various outcomes were examined, in particular cervical stump carcinoma, sexual function, urinary function, psychic health and operative complications.
Conclusion The risk of carcinoma of the stump is very low and techniques to remove the transformation zone may all but eliminate this risk. There appears not to be any long‐term statistically significant difference between total and subtotal hysterectomy with respect to sexual function, urinary function or psychic health. Comparisons between different operative techniques are lacking; however operative complications involving the urinary tract and postoperative sepsis are less common with cervical conservation. With improvements in laparoscopic technique, this modality of surgery appears to be as safe as conventional surgery with particular benefits evident for the supracervical approach.
Sling procedure for urinary stress incontinence, using vaginal and laparoscopic approaches: report on a case series of 33 patients
Authors: Aubard Y. , Piver P. 
Published: November 2003

Objective To describe our experience with a new sling procedure for the management of urinary stress incontinence in women, using a laparoscopic approach via the retropubic space.
Design In a 22‐month period, 33 patients underwent this procedure in which an absorbable synthetic sling (PDS Ethicon) is used. The first stage is laparoscopic; the retropubic space is dissected until 2–3 cm of the ileopectineal ligaments are visible. The second stage is vaginal: the bladder is dissected and the retropubic space reached by finger dissection. The sling is pushed through the retropubic space from the vagina toward the abdominal cavity. The third stage is laparoscopic; the two ends of the sling are stapled onto each pectineal ligament. Most of the patients underwent a hysterectomy and a posterior perineorraphy.
Results The average duration of the operation was 1 h 35 min, and the average blood loss was 2.52 g dl−1. One bladder wound was repaired by laparoscopy. No switch to laparotomy was necessary. The mean follow‐up period was 13.86 months. Of the patients, 72.7% were completely continent and 24.2% experienced partial improvement. The operation was a failure for one patient (3%).
Conclusion The aim of the procedure described is to reduce the complication rate by avoiding laparotomy. The results were satisfactory for the first 33 cases. A randomized study is now under way to compare the new and classical procedure (using vaginal and laparotomic approaches).
Haematometra—endometrial resection— sterilization syndrome
Authors: Gannon M. J. , Johnson N. , Watters J. K. , Lilford R.J. 
Published: November 2003

Objective To determine the predisposing causes of haematometra after endometrial ablation.
Subjects 300 women who had undergone electrosurgical endometrial ablation for menorrhagia. Interventions Either the loop or the rollerball electrode was used exclusively for each operation. Each woman had an ultrasound scan of the uterus at 4 months after surgery.
Main outcome measure Presence of haematometra.
Results Factors which predisposed to haematometra included loop resection (P=0.007) and tubal sterilization (P=0.005).
Conclusion An association exists between haematometra, endometrial resection and sterilization.
Health care provider and self‐assessment of health status and sexual behaviour in HIV‐seropositive young men with haemophilia
Authors: Nuss R. , Stultz J. , Remafedi G. , Lloyd Schulz S. , Cohen A. 
Published: November 2003

We hypothesized that persons with HIV who perceive themselves as having waning health status may participate in fewer sexual behaviours than HIV‐infected persons without HIV‐related health problems. The object‐ives of this study were to compare health care provider responses with participant responses for health status and for sexual activity and to examine the relationship of HIV‐related health status to the sexual behaviour of HIV‐seropositive adolescents and young men with haemophilia.A detailed questionnaire designed by researchers from 11 participating US haemophilia treatment sites and CDC personnel was administered to 306 HIV‐seropositive young men with haemophilia aged 12–25 years. A health care provider from the haemophilia treatment centre also completed a questionnaire on each respondent.Self‐assessment of HIV‐related health status was similar to provider assessment of health status. Providers accurat‐ely assessed participant sexual activity (overall Kappa = 0.62). Participation in vaginal intercourse and condom use was independent of health status.Following extensive educational efforts, most HIV‐seropositive adolescents and young men with haemophilia are aware of the relationship between their HIV seropositivity and health status. Waning health status does not reduce participation in penetrative sexual behaviours or increase use of condoms. HIV prevention efforts should continue for this population.
Porcine factor VIII (Hyate: C®): in vitro stability, microbiological safety and effect of heparin
Authors: Travis S. F. , Burns N. , Hofmann P. 
Published: November 2003

The in vitro stability of porcine factor VIII (PF VIII) was evaluated when it was reconstituted with sterile water (PF VIIISW) to ≈ 30 U PFVIII mL−1, as per the manufacturer’s recommendations, and stored in plastic syringes at room temperature, with and without heparin and at four different dilutions. PF VIII was prepared antiseptically without laminar airflow and remained sterile at room temperature for 1 week. PF VIIISW retained at least 88% of baseline activity for 48 h and 74–86% for 72 h. Addition of heparin 1 unit mL−1 solution resulted in a decrease in the stability of PF VIIISW to 72–74 % of baseline values by 24 h. Reconstituted PF VIIISW, further diluted with normal saline to 10–24 U PF VIII mL−1, retained 98% of baseline activity for 48 h and 84% of baseline for 72 h. PF VIII diluted to 6 U mL−1, however, retained 100% baseline activity for only 24 h, and declined to 71% and 64 % of baseline by 48 and 72 h, respectively. PF VIII reconstituted with normal saline, instead of sterile water, retained 90% or more of baseline activity for a minimum of 4 days. Once reconstituted, PF VIII appeared to be more stable at room temperature than when stored in the refrigerator.These in vitro stability studies confirm that PF VIII (30 U mL−1) can be given effectively by prolonged continuous infusion, since it retains 88% baseline activity at room temperature in a plastic syringe for a minimum of 48 h, remains sterile and will maintain baseline PF VIII levels when further diluted with saline.