bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seven‐day therapy for Helicobacter pylori in the United States
Authors: Vakil N. , Lanza F. , Schwartz H. , Barth J. 
Published: July 2004

SummaryBackground : The ideal duration of Helicobacter pylori treatment in the United States and whether eradication therapy is as successful in nonulcer dyspepsia as in peptic ulcer disease are controversial topics.Aim : This study compared the efficacy of 3‐, 7‐ and 10‐day triple therapies with rabeprazole to a 10‐day omeprazole control triple therapy for the eradication of Helicobacter pylori in patients with and without peptic ulcer disease in the United States.Methods : This was a multicentre, double‐blind, randomized, parallel‐group trial. A total of 803 patients with H. pylori infection (determined by [13C]urea breath test and rapid urease test or culture) received either rabeprazole 20 mg b.d., amoxicillin 1000 mg b.d., and clarithromycin 500 mg b.d. for 3, 7, or 10 days, or 10 days of omeprazole 20 mg b.d. with the same antibiotic regimen (control). H. pylori status was assessed by [13C]urea breath test ≥6 weeks after completing treatment.Results : In intent‐to‐treat patients, the eradication percentages achieved for the rabeprazole‐based treatments were: 3‐day, 27% (95% confidence interval: 21%–34%); 7‐day, 77% (95% confidence interval: 71%–83%); and 10‐day, 78% (95% confidence interval: 72%–84%). The eradication percentage with the 10‐day omeprazole‐based treatment was 73% (95% confidence interval: 67%–79%). There was no statistically significant difference between the 7‐day rabeprazole‐based regimen and the 10‐day rabeprazole‐ and omeprazole‐based regimens.Conclusions : Seven‐day therapy with rabeprazole, clarithromycin, and amoxicillin is similar in efficacy to 10‐day therapies and had similar efficacy in patients with and without ulcer disease.
Myeloma cells can directly contribute to the pool of RANKL in bone bypassing the classic stromal and osteoblast pathway of osteoclast stimulation
Authors: Lai F. P. L. , Cole‐Sinclair M. , Cheng W.‐J. , Quinn J. M. W. , Gillespie M. T. , Sentry J. W. , Schneider H.‐G. 
Published: July 2004

SummaryThe ratio of osteoprotegerin [OPG, tumour necrosis factor receptor superfamily, member 11b (TNFRSF11B)] to receptor activator of nuclear factor κB ligand [RANKL, tumour necrosis factor (ligand) superfamily, member 11 (TNFSF11)] in bone is critical for the regulation of bone remodelling. Myeloma cells can home to bone, triggering increased RANKL and decreased OPG expression by stromal cells, leading to osteolysis. Whether myeloma cells contribute directly to the pool of RANKL or OPG in bone has been contentious. Here we provide evidence of RANKL expression by reverse transcription polymerase chain reaction and in situ hybridization, demonstrating transcripts encoding both the membrane‐bound and secreted forms of RANKL in five human multiple myeloma cell lines (LP‐1, NCI‐H929, OPM‐2, RPMI8226, U266) and myeloma cells purified from bone marrow aspirates of myeloma patients. We demonstrated that RANKL encoding mRNAs are translated to protein by antibody detection of RANKL. In vitro assays showed that myeloma cells induced bone marrow derived mononuclear cells to differentiate into adherent tartrate‐resistant acid phosphatase positive multinucleated cells, indicative of the formation of functional osteoclasts. This differentiation could also be achieved with passaged myeloma media alone, implicating secreted products. Finally, we provide evidence that the differentiation observed is at least in part the result of myeloma cell expression of RANKL. We therefore conclude that myeloma cells can directly contribute to the pool of RANKL in bone.
Molecular basis of Japanese variants of pyrimidine 5′‐nucleotidase deficiency
Authors: Kanno Hitoshi , Takizawa Takenori , Miwa Shiro , Fujii Hisaichi 
Published: July 2004

SummaryThe type‐I isoform of pyrimidine 5′‐nucleotidase (P5N‐I) has an important role in the catabolism of pyrimidine mononucleotides during erythroid maturation. Two alternatively spliced forms of P5N‐I mRNA have been identified, and we found another alternatively spliced form in reticulocytes, which included an additional 87‐bp sequence. The sequence is located 6·2‐kb downstream of the exon 2 and 2·7‐kb upstream of the exon 3 sequence; consequently, the P5N‐I gene encodes 11 exons, which span approximately 48 kb. We identified five novel mutations in nine families with P5N‐I deficiency: two missense mutations (425C, 721C), one splice mutation (339C), one 1‐bp insertion (251‐insA‐252) and one 9‐bp deletion (del 192‐200). All patients were homozygous for each mutation. The mutant P5N‐I with 721C (G241R) had lower affinity for cytidine monophosphate, suggesting that Gly241 is important for substrate binding. Haplotype analysis showed that 721C, which had been identified in five unrelated families, was a founder mutation. The mutant P5N was then expressed in Cos‐7. The degradation of P5N with 425C (L142P) was significantly faster than a wild‐type control, and proteasome inhibitors restored the stability of L142P. These data suggest that L142P increases susceptibility to the degradation by the ubiquitin‐proteasome pathway.
In search of perfect motherhood for imperfect childhood – experiences of 22 Chinese mothers
Authors: Pun S. H. , Ma Joyce L. C. , Lai Kelly C. C. 
Published: July 2004

ABSTRACTMotherhood is subjectively defined and contextually based. This article describes and unfolds the experience of 22 Chinese mothers in Hong Kong in cultivating a sense of perfect motherhood for their children who have mental or behavioural problems that require psychiatric consultation. The mother, the significant others and the general public perceive the latter as a form of imperfection. The mothering experiences were full of frustrations, ambivalence, stresses and tensions, and were crystallized by the repeated theme of mother‐blaming and self‐blame by the mother. Despite the hardships, these Chinese mothers have gradually developed self‐confidence and pride, and have found ways to cope with the burden of care. Implications for practice are highlighted at the end of the paper.
Increased width of the apical periodontal membrane space in endodontically treated teeth may represent favourable healing
Authors: Halse A. , Molven O. 
Published: July 2004

AbstractAim  To examine cases showing increased width of the periodontal space (IW) at a long‐term follow‐up examination and to determine whether this finding could be explained by endodontic or nonendodontic factors.Methodology  A series of intraoral radiographs was obtained from 131 patients 20–27 years after root canal treatment. The same individuals had been examined 10 years earlier, and radiographs taken immediately after treatment were also available. Fourteen roots (5.6%) demonstrated increased width of the apical periodontal space at the end of the study period. These were subjected to further analysis in an attempt to disclose possible explanatory factors.Results  Two of the 14 cases had reduced marginal bone levels interpreted as the origin of the IW. In three cases, overextended root filling material present 10 years earlier had disappeared and the persistent IW was interpreted as representing a remodelling process. In six cases the findings were explained as being caused by physical and anatomical factors that represented healing without complete re‐formation of the apical periodontal structures, or both. Three cases were judged as unfavourable, on the basis of lacking progress in healing, unsatisfactory obturation of the apical portion of the root canal or dentine resorption close to the apical end of the root filling.Conclusion  Most of the 14 IW cases examined after 20–27 years could be explained by reduced marginal bone support, or by physical and anatomical factors or they might represent incomplete reformation of the typical apical morphology and were thereby recorded as favourable outcomes.
Delayed‐relaxed response explained by hyperactivation of RelE
Authors: Christensen Susanne K. , Gerdes Kenn 
Published: July 2004

Summary Escherichia coli encodes two rel loci, both of which contribute to the control of synthesis of macromolecules during amino acid starvation. The product of relA (ppGpp synthetase I) is responsible for the synthesis of guanosine tetraphosphate, ppGpp, the signal molecule that exerts stringent control of stable RNA synthesis. The second rel locus, relBE, was identified by mutations in relB that confer a so‐called ‘delayed‐relaxed response’ characterized by continued RNA synthesis after a lag period of ≈ 10 min after the onset of amino acid starvation. We show here that the delayed‐relaxed response is a consequence of hyperactivation of RelE. As in wild‐type cells, [ppGpp] increased sharply in relB101 relE cells after the onset of starvation, but returned rapidly to the prestarvation level. RelE is a global inhibitor of translation that is neutralized by RelB by direct protein–protein interaction. Lon protease activates RelE during amino acid starvation by degradation of RelB. We found that mutations in relB that conferred the delayed‐relaxed phenotype destabilized RelB. Such mutations confer severe RelE‐dependent inhibition of translation during amino acid starvation, indicating hyperactivation of RelE. Hyperactivation of RelE during amino acid starvation was shown directly by measurement of RelE‐mediated cleavage of tmRNA. The RelE‐mediated shutdown of translation terminated amino acid consumption and explains the rapid restoration of the ppGpp level observed in relB mutant cells. Restoration of the prestarvation level of ppGpp, in turn, allows for the resumption of stable RNA synthesis seen during the delayed‐relaxed response.
Intracellular effectors regulating the activity of the Lactococcus lactis CodY pleiotropic transcription regulator
Authors: Petranovic Dina , Guédon Eric , Sperandio Brice , Delorme Christine , Ehrlich Dusko , Renault Pierre 
Published: July 2004

SummaryCodY is a pleiotropic transcriptional regulator conserved in low‐G+C Gram‐positive bacteria. Two distinct signals have been shown independently to influence the activity of this regulator: the level of intracellular GTP in Bacillus subtilis and the level of intracellular branched‐chain amino acids (BCAA) isoleucine, leucine and valine in Lactococcus lactis. Measurement of BCAA and GTP levels in several environmental conditions showed that L. lactis CodY responded to the intracellular BCAA concentrations but not to physiological fluctuations in intracellular GTP. In addition, we demonstrated that CodY from L. lactis did not respond to intracellular GTP even when complementing CodY activity in B. subtilis. However, L. lactis CodY activity could still be modulated in B. subtilis by adding a rich nitrogen source to the growth media. This finding suggests that only BCAA are sensed by L. lactis CodY, whereas both GTP and BCAA signals may be integrated by B. subtilis CodY. The difference in the function of CodY from B. subtilis and L. lactis seems to reflect the difference in the physiology of these two bacteria.
Identification of a 67‐amino‐acid region of the Plasmodium falciparum variant surface antigen that binds chondroitin sulphate A and elicits antibodies reactive with the surface of placental isolates
Authors: Gamain Benoit , Smith Joseph D. , Avril Marion , Baruch Dror I. , Scherf Artur , Gysin Jurg , Miller Louis H. 
Published: July 2004

SummaryThe complications of malaria in pregnancy are caused by the massive sequestration of parasitized erythrocytes (PE) in the placenta. Placental isolates of Plasmodium falciparum are unusual in that they do not bind the primary microvasculature receptor CD36 but instead bind chondroitin sulphate A (CSA). Pregnant mothers develop antibodies that recognize placental variants worldwide, suggesting that a vaccine against malaria in pregnancy is possible. Some members of the Duffy binding‐like γ (DBL‐γ) domain of the large and diverse P. falciparum erythrocyte membrane protein‐1 (PfEMP‐1) family, when expressed on Chinese hamster ovary (CHO) cells, bind CSA. To characterize better the molecular requirements for DBL‐γ adhesion to CSA, we determined the binding of various DBL‐γ domains. Most DBL‐γ did not bind CSA, and no conserved region was identified that strictly differentiated binders from non‐binders. Structure–function analysis of the FCR3‐CSA DBL‐γ domain localized the minimal CSA binding region to a 67‐residue fragment. This region was partially conserved among some binding sequences. Serum from a rabbit immunized with the minimal domain reacted with CSA‐binding parasite lines, but not with non‐CSA‐adherent PE lines that adhered to CD36 and other receptors. The identification of a minimal binding region from a highly variable cytoadherent family may have application for a vaccine against malaria in pregnancy.
Interactions underlying assembly of the Escherichia coli AcrAB–TolC multidrug efflux system
Authors: Touzé Thierry , Eswaran Jeyanthy , Bokma Evert , Koronakis Eva , Hughes Colin , Koronakis Vassilis 
Published: July 2004

SummaryThe major Escherichia coli multidrug efflux pump AcrAB–TolC expels a wide range of antibacterial agents. Using in vivo cross‐linking, we show for the first time that the antiporter AcrB and the adaptor AcrA, which form a translocase in the inner membrane, interact with the outer membrane TolC exit duct to form a contiguous proteinaceous complex spanning the bacterial cell envelope. Assembly of the pump appeared to be constitutive, occurring in the presence and absence of drug efflux substrate. This contrasts with substrate‐induced assembly of the closely related TolC‐dependent protein export machinery, possibly reflecting different assembly dynamics and degrees of substrate responsiveness in the two systems. TolC could be cross‐linked independently to AcrB, showing that their large periplasmic domains are in close proximity. However, isothermal titration calorimetry detected no interaction between the purified AcrB and TolC proteins, suggesting that the adaptor protein is required for their stable association in vivo. Confirming this view, AcrA could be cross‐linked independently to AcrB and TolC in vivo, and calorimetry demonstrated energetically favourable interactions of AcrA with both AcrB and TolC proteins. AcrB was bound by a polypeptide spanning the C‐terminal half of AcrA, but binding to TolC required interaction of N‐ and C‐terminal polypeptides spanning the lipoyl‐like domains predicted to present the intervening coiled‐coil to the periplasmic coils of TolC. These in vivo and in vitro analyses establish the central role of the AcrA adaptor in drug‐independent assembly of the tripartite drug efflux pump, specifically in coupling the inner membrane transporter and the outer membrane exit duct.
Channels in microbes: so many holes to fill
Authors: Kung Ching , Blount Paul 
Published: July 2004

SummaryAmong players in neurobiology, ion channels are the demigods that underlie all our senses, behaviour and intelligence. In animals, these ‘gated pores’ detect ligands, voltage, heat or stretch forces and emit electric or ionic signals. Patch clamp and genome sequencing now show that nearly all microbes also have these ‘smart’ molecules. Microbial channel proteins have yielded crystal structures so dear to neuroscientists. However, their natural roles in microbial physiology remain largely unknown. The intellectual and technical schisms between ‘neuro’ and ‘micro’ biology must be bridged before we know how we became so smart, and whether microbes are just as smart.
Low temperature effects on photosynthesis and growth of grapevine
Authors: HENDRICKSON L. , BALL M. C. , WOOD J. T. , CHOW W. S. , FURBANK R. T. 
Published: July 2004

ABSTRACTGrowth and photosynthesis of grapevine (Vitis vinifera L.) planted on two sloping cool climate vineyards were measured during the early growth season. At both vineyards, a small difference in mean minimum air temperature (1–3 °C) between two microsites accumulated over time, producing differences in shoot growth rate. The growth rates of the warmer (upper) microsite were 34–63% higher than the cooler (lower) site. Photosynthesis measurements of both east and west canopy sides revealed that the difference in carbon gain between the warmer and cooler microsites was due to low temperatures restricting the photosynthetic contribution of east‐facing leaves. East‐facing leaves at the warmer microsite experienced less time at suboptimal temperature while being exposed to high irradiance, contributing to an average 10% greater net carbon gain compared to the east‐facing leaves at the cooler microsite. This chilling‐induced reduction in photosynthesis was not due to net photo‐inhibition. Further analysis revealed that CO2‐ and light‐saturated photosynthesis of grapevines was restricted by stomatal closure from 15 to 25 °C and by a limitation of RuBP regeneration and/or end‐product limitation from 5 to 15 °C. Changes in photosynthetic carboxylation efficiency implied that Rubisco activity may also play a regulatory role at all temperatures. This restriction of total photosynthetic carbon gain is proposed to be a major contributor to the temperature dependence of growth rate at both vineyards during the early season growth period.
The GHOST terminal oxidase regulates developmental programming in tomato fruit
Authors: BARR J. , WHITE W. S. , CHEN L. , BAE H. , RODERMEL S. 
Published: July 2004

ABSTRACTThe tomato ghost and Arabidopsis immutans variegation mutants define orthologous genes for a chloroplast quinol oxidase that bears similarity to the mitochondrial alternative oxidase. In this study tomato fruit ripening was used as a model to explore the function of this oxidase. It was found that a lack of GH impacts the biogenesis of chloroplasts and chromoplasts, as well as pericarp tissue morphogenesis, during the ripening process. Most ripening‐related genes are expressed normally during gh fruit development, but late in the process there is a specific repression of mRNA accumulation from carotenoid biosynthetic genes, perhaps due to retrograde (plastid‐to‐nucleus) signalling pathways mediated by lycopene. Metabolic profiling revealed that wild‐type red‐ripe fruit accumulate multiple isomers of phytoene, phytofluene, and ζ‐carotene, but that the composition of these isomers is different in ripe gh fruit. Profiling  also  revealed  that  there  is  an  enhanced  ratio  of β‐carotene to lycopene in the ripe gh fruit. This explains the orange colour of these fruit, and is consistent with the proposal that the β‐cyclization step plays a pivotal role in regulating the partitioning of pathway intermediates. The total carotenoid content of the mutant fruit is significantly higher than normal due to an accumulation of phytoene. Phytoene accumulation, together with an up‐regulation of GH transcripts during ripening, supports the notion that GH plays a central role in carotenogenesis in chromoplasts. However, GH mRNAs are also expressed in tissues and organs other than fruit. This is consistent with the possibility that GH mediates quinol oxidation from a variety of pathways that converge on plastoquinol in plastid membranes.
Short‐term effects of fertilization on loblolly pine (Pinus taedaL.) physiology
Authors: GOUGH C. M. , SEILER J. R. , MAIER C. A. 
Published: July 2004

ABSTRACTFertilization commonly increases biomass production in loblolly pine (Pinus taedaL.). However, the sequence of short‐term physiological adjustments allowing for the establishment of leaf area and enhanced growth is not well understood. The effects of fertilization on photosynthetic parameters, root respiration, and growth for over 200 d following the application of diammonium phosphate were intensively investigated in an effort to establish a relative sequence of events associated with improved growth. Root respiration, foliar nitrogen concentration [N]f, and light‐saturated net photosynthesis (Asat) temporarily increased following fertilization.Asatwas correlated positively with [N]fwhen non‐fertilized and fertilized treatments were pooled (R2 = 0.47). Increased photosynthetic capacity following fertilization was due to both improved photochemical efficiency and capacity and enhanced carboxylation capacity of Rubisco. Positive effects of fertilization on growth were observed shortly afterAsatincreased. Fertilized seedlings had 36.5% more leaf area and 36.5% greater total dry weight biomass at 211 d following fertilization. It is concluded that fertilization temporarily increased photosynthetic capacity, which resulted in a pool of photo‐assimilate used to build leaf area. The N from fertilizer initially invested in photosynthetic structures and enzymes probably re‐translocated to newly developing foliage, explaining the reduction in [N]fandAsatthat was observed after peak levels were achieved following fertilization.
Cold induction of EARLI1, a putative Arabidopsis lipid transfer protein, is light and calcium dependent
Authors: BUBIER J. , SCHLÄPPI M. 
Published: July 2004

ABSTRACTAs sessile organisms, plants must adapt to their environment. One approach toward understanding this adaptation is to investigate environmental regulation of gene expression. Our focus is on the environmental regulation of EARLI1, which is activated by cold and long‐day photoperiods. Cold activation of EARLI1 in short‐day photoperiods is slow, requiring several hours at 4 °C to detect an increase in mRNA abundance. EARLI1 is not efficiently cold‐activated in etiolated seedlings, suggesting that photomorphogenesis is necessary for its cold activation. Cold activation of EARLI1 is inhibited in the presence of the calcium channel blocker lanthanum chloride or the calcium chelator EGTA. Addition of the calcium ionophore Bay K8644 results in cold‐independent activation of EARLI1. These data suggest that EARLI1 is not an immediate target of the cold response, and that calcium flux affects its expression. EARLI1 is a putative secreted protein and has motifs found in lipid transfer proteins. Over‐expression of EARLI1 in transgenic plants results in reduced electrolyte leakage during freezing damage, suggesting that EARLI1 may affect membrane or cell wall stability in response to low temperature stress.