bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solvation in pure and mixed solvents: Some recent developments
Authors: El Seoud Omar A. 
Published: June 2007

AbstractThe effect of solvents on the spectra, absorption, or emission of substances is called solvatochromism; it is due to solute/solvent nonspecific and specific interactions, including dipole/dipole, dipole-induced/dipole, dispersion interactions, and hydrogen bonding. Thermo-solvatochromism refers to the effect of temperature on solvatochromism. The molecular structure of certain substances, polarity probes, make them particularly sensitive to these interactions; their solutions in different solvents have distinct and vivid colors. The study of both phenomena sheds light on the relative importance of the solvation mechanisms. This account focuses on recent developments in solvation in pure and binary solvent mixtures. The former has been quantitatively analyzed in terms of a multiparameter equation, modified to include the lipophilicity of the solvent. Solvation in binary solvent mixtures is complex because of the phenomenon of "preferential solvation" of the probe by one component of the mixture. A recently introduced solvent exchange model allows calculation of the composition of the probe solvation shell, relative to that of bulk medium. This model is based on the presence of the organic solvent (S), water (W), and a 1:1 hydrogen-bonded species (S-W). Solvation by the latter is more efficient than by its precursor solvents, due to probe/solvent hydrogen-bonding and hydrophobic interactions. Dimethylsulfoxide (DMSO) is an exception, because the strong DMSO/W interactions probably deactivate the latter species toward solvation. The relevance of the results obtained to kinetics of reactions is briefly discussed by addressing temperature-induced desolvation of the species involved (reactants and activated complexes) and the complex dependence of kinetic data (observed rate constants and activation parameters) in binary solvent mixtures on medium composition.
Growth Hormone (GH) Receptor Isoform in Acromegaly: Lower Concentrations of GH but Not Insulin-Like Growth Factor-1 in Patients with a Genomic Deletion of Exon 3 in the GH Receptor Gene
Authors: Schmid Christoph , Krayenbuehl Pierre-Alexandre , Bernays René-Ludwig , Zwimpfer Cornelia , Maly Friedrich E , Wiesli Peter 
Published: June 2007

Abstract
Background: A genomic deletion of exon 3 (d3-GHR) of the growth hormone (GH) receptor (GHR) has been linked to the effectiveness of GH therapy in children with GH deficiency. Carriers of the d3-GHR genotype had higher GH-induced growth rates than children homozygous for the full-length (fl)-GHR. The aim of this study was to test whether the relationship between GH and insulin-like growth factor-1 (IGF-1) concentrations is influenced by the GHR genotype in patients with acromegaly.
Methods: Study participants were 44 adult patients with established diagnosis of acromegaly. The genotype of the GHR was determined in leukocyte DNA from peripheral blood. Clinical and biochemical findings at the time of diagnosis of acromegaly were obtained from the medical records of the patients.
Results: fl-GHR homozygosity was found in 22 (50%) of patients, and 22 (50%) of patients had at least 1 d3 allele (d3-GHR). Demographic and clinical characteristics (age, height, weight, estimated duration of disease, and mean tumor size) of the 2 groups were comparable. Median (range) serum IGF-1 concentrations at the time of diagnosis were 670 (447–1443) μg/L in the fl-GHR group and 840 (342–1494) μg/L in the d3-GHR group (P = not significant). Basal GH concentrations were higher in the fl-GHR group [29.7 (3.8–159) μg/L] than in the d3-GHR group [8.4 (2.6–74 μg/L), P = 0.002], and so were mean (30.4 vs 6.1 μg/L, P = 0.005) and nadir (20.5 vs 5.1 μg/L, P = 0.003) GH concentrations during an oral glucose tolerance test.
Conclusions: The GHR fl/d3 genotype modulates the relationship between GH and IGF-1 concentrations in patients presenting with acromegaly.
Idiosyncratic cleavage and ligation activity of individual hammerhead ribozymes and core sequence variants thereof
Authors: Przybilski Rita , Hammann Christian 
Published: June 2007

Abstract
The hammerhead ribozyme is a small RNA endonuclease found in sub-viral plant pathogens, in transcripts from certain animal satellite DNAs and encoded at distinct loci of Arabidopsis thaliana. Kinetic analyses of tertiary stabilised ribozymes from peach latent mosaic viroid (PLMVd), Schistosoma mansoni and A. thaliana revealed a ten-fold difference in cleavage rates. Core nucleotide variations affected cleavage reactions least in the A. thaliana ribozyme, and most in the S. mansoni ribozyme. The reverse ligation reaction was catalysed efficiently by the PLMVd and A. thaliana ribozymes. The different behaviour of the individual hammerhead ribozymes is discussed in terms of structure and function.
RNA self-processing towards changed topology and sequence oligomerization
Authors: Pieper Stefan , Vauléon Stéphanie , Müller Sabine 
Published: June 2007

Abstract
Reversible chemistry, allowing for chain-forming as well as chain-breaking steps, is important for biological self-organization. In this context, ribozymes, catalyzing both RNA cleavage and ligation, may have significantly contributed to extending the sequence space and length of RNA molecules in early life forms. Here we present an engineered RNA that self-processes by passing through a number of cleavage and ligation steps. Intermolecular reactions compete with intramolecular reactions, resulting in a variety of products. Our results demonstrate that RNA can undergo self-oligomerization, which may have been important for extending the RNA genome size in RNA world scenarios.
A chemo-genetic approach for the study of nucleobase participation in nucleolytic ribozymes
Authors: Lilley David M.J. 
Published: June 2007

Abstract
A novel chemo-genetic approach for the analysis of general acid-base catalysis by nucleobases in ribozymes is reviewed. This involves substitution of a C-nucleoside with imidazole in place of a natural nucleobase. The Varkud satellite ribozyme in which the nucleobase at the critical 756 position has been replaced by imidazole is active in both cleavage and ligation reactions. Similarly, a modified hairpin ribozyme with the nucleobase at position 8 substituted by imidazole is active in cleavage and ligation reactions. Although the rates are lower than those of the natural ribozymes, they are significantly greater than other variants at these positions. The dependence of the hairpin ribozyme reaction rates on pH has been studied. Both cleavage and ligation reactions display a bell-shaped pH dependence, consistent with general acid-base catalysis involving the nucleotide at position 8.
The spliceosome: a ribozyme at heart?
Authors: Valadkhan Saba 
Published: June 2007

Abstract
The spliceosome, the multi-megadalton molecular machine that performs splicing, consists of over 200 different proteins and five small nuclear RNAs (snRNAs). Extensive mechanistic and structural similarities to self-splicing group II introns, large ribozymes found in prokaryotes and lower eukaryotes that catalyze an identical reaction, strongly suggest that the spliceosomal RNAs are in fact the catalytic components of the spliceosome. Of the five spliceosomal RNAs, U2 and U6 are the only ones that are absolutely required for both steps of splicing. These two snRNAs form an elaborate base-paired complex that might in fact constitute the active site of the spliceosome.
Plasminogen-dependent internalization of soluble melanotransferrin involves the low-density lipoprotein receptor-related protein and annexin II
Authors: Michaud-Levesque Jonathan , Demeule Michel , Béliveau Richard 
Published: June 2007

Abstract
We investigated the effect of plasminogen (Plg) on the internalization of recombinant soluble melanotransferrin (sMTf) using U87 human glioblastoma cells and murine embryonic fibroblasts (MEF) deficient in the low-density lipoprotein receptor-related protein (LRP). Using biospecific interaction analysis, both Glu- and Lys-Plg were shown to interact with immobilized sMTf. The binding of sMTf at the cell surface increased in the presence of both forms of Plg in control and in LRP-deficient MEF cells, whereas the uptake was strongly stimulated only by Lys-Plg in control MEF and U87 cells. In addition, in the presence of Lys-Plg, the internalization of sMTf was a saturable process, sensitive to temperature and dependent on the integrity of lysine residues. The addition of the receptor-associated protein, lactoferrin and aprotinin, as well as a monoclonal antibody (mAb) directed against LRP, inhibited the Lys-Plg-dependent uptake of sMTf. These results suggest an important role for LRP in this process. In addition, using binding and uptake assays in the presence of anti-annexin II mAb, we showed that annexin II might be responsible for the initial binding of sMTf in the presence of Plg. Our results suggest a Plg-mediated internalization mechanism for the clearance of sMTf via annexin II and LRP.
Could the effect of modeled microgravity on osteogenic differentiation of human mesenchymal stem cells be reversed by regulation of signaling pathways?
Authors: Zheng Qiang , Huang Guoping , Yang Jinfeng , Xu Yulin , Guo Chunjuan , Xi Yongmei , Pan Zhijun , Wang Jinfu 
Published: June 2007

Abstract
Microgravity (MG) results in a reduction in bone formation. Bone formation involves osteogenic differentiation from mesenchymal stem cells (hMSCs) in bone marrow. We modeled MG to determine its effects on osteogenesis of hMSCs and used activators or inhibitors of signaling factors to regulate osteogenic differentiation. Under osteogenic induction, MG reduced osteogenic differentiation of hMSCs and decreased the expression of osteoblast gene markers. The expression of Runx2 was also inhibited, whereas the expression of PPARγ2 increased. MG also decreased phosphorylation of ERK, but increased phosphorylation of p38MAPK. SB203580, a p38MAPK inhibitor, was able to inhibit the phosphorylation of p38MAPK, but did not reduce the expression of PPARγ2. Bone morphogenetic protein (BMP) increased the expression of Runx2. Fibroblast growth factor 2 (FGF2) increased the phosphorylation of ERK, but did not significantly increase the expression of osteoblast gene markers. The combination of BMP, FGF2 and SB203580 significantly reversed the effect of MG on osteogenic differentiation of hMSCs. Our results suggest that modeled MG inhibits the osteogenic differentiation and increases the adipogenic differentiation of hMSCs through different signaling pathways. Therefore, the effect of MG on the differentiation of hMSCs could be reversed by the mediation of signaling pathways.
Group II introns: structure, folding and splicing mechanism
Authors: Fedorova Olga , Zingler Nora 
Published: June 2007

Abstract
Group II introns are large autocatalytic RNAs found in organellar genomes of plants and lower eukaryotes, as well as in some bacterial genomes. Interestingly, these ribozymes share characteristic traits with both spliceosomal introns and non-LTR retrotransposons and may have a common evolutionary ancestor. Furthermore, group II intron features such as structure, folding and catalytic mechanism differ considerably from those of other large ribozymes, making group II introns an attractive model system to gain novel insights into RNA biology and biochemistry. This review explores recent advances in the structural and mechanistic characterization of group II intron architecture and self-splicing.
A 2′-methyl or 2′-methylene group at G+1 in precursor tRNA interferes with Mg2+ binding at the enzyme-substrate interface in E-S complexes of E. coli RNase P
Authors: Cuzic Simona , Hartmann Roland K. 
Published: June 2007

Abstract
We analyzed processing of precursor tRNAs carrying a single 2′-deoxy, 2′-OCH3, or locked nucleic acid (LNA) modification at G+1 by Escherichia coli RNase P RNA in the absence and presence of its protein cofactor. The extra methyl or methylene group caused a substrate binding defect, which was rescued at higher divalent metal ion (M2+) concentrations (more efficiently with Mn2+ than Mg2+), and had a minor effect on cleavage chemistry at saturating M2+ concentrations. The 2′-OCH3 and LNA modification at G+1 resulted in higher metal ion cooperativity for substrate binding to RNase P RNA without affecting cleavage site selection. This indicates disruption of an M2+ binding site in enzyme-substrate complexes, which is compensated for by occupation of alternative M2+ binding sites of lower affinity. The 2′-deoxy modification at G+1 caused at most a two-fold decrease in the cleavage rate; this mild defect relative to 2′-OCH3 and LNA at G+1 indicates that the defect caused by the latter two is steric in nature. We propose that the 2′-hydroxyl at G+1 in the substrate is in the immediate vicinity of the M2+ cluster at the phosphates of A67 to U69 in helix P4 of E. coli RNase P RNA.
Mechanisms of Cancer-Related Fatigue
Authors: Ryan Julie L. , Carroll Jennifer K. , Ryan Elizabeth P. , Mustian Karen M. , Fiscella Kevin , Morrow Gary R. 
Published: June 2007

AbstractCancer-related fatigue (CRF) is one of the most prevalent symptoms patients with cancer experience, both during and after treatment. CRF is pervasive and affects patients' quality of life considerably. It is important, therefore, to understand the underlying pathophysiology of CRF in order to develop useful strategies for prevention and treatment. At present, the etiology of CRF is poorly understood and the relative contributions of the neoplastic disease, various forms of cancer therapy, and comorbid conditions (e.g., anemia, cachexia, sleep disorders, depression) remain unclear. In any individual, the etiology of CRF probably involves the dysregulation of several physiological and biochemical systems. Mechanisms proposed as underlying CRF include 5-HT neurotransmitter dysregulation, vagal afferent activation, alterations in muscle and ATP metabolism, hypothalamic–pituitary–adrenal axis dysfunction, circadian rhythm disruption, and cytokine dysregulation. Currently, these hypotheses are largely based on evidence from other conditions in which fatigue is a characteristic, in particular chronic fatigue syndrome and exercise-induced fatigue. The mechanisms that lead to fatigue in these conditions provide a theoretical basis for future research into the complex etiology of this distressing and debilitating symptom. An understanding of relevant mechanisms may offer potential routes for its prevention and treatment in patients with cancer.Disclosure of potential conflicts of interest is found at the end of this article.
Cancer-Related Fatigue: The Scale of the Problem
Authors: Hofman Maarten , Ryan Julie L. , Figueroa-Moseley Colmar D. , Jean-Pierre Pascal , Morrow Gary R. 
Published: June 2007

Abstract
Fatigue is one of the most common and debilitating symptoms experienced by patients with cancer. Cancer-related fatigue (CRF) is characterized by feelings of tiredness, weakness, and lack of energy, and is distinct from the “normal” drowsiness experienced by healthy individuals in that it is not relieved by rest or sleep. It occurs both as a consequence of the cancer itself and as a side effect of cancer treatment, although the precise underlying pathophysiology is largely unknown. CRF may be an early symptom of malignant disease and is reported by as many as 40% of patients at diagnosis. Virtually all patients expect fatigue from cancer therapy. Up to 90% of patients treated with radiation and up to 80% of those treated with chemotherapy experience fatigue. CRF continues for months and even years ollowing completion of treatment in approximately one third of the patients with cancer. The impact of CRF on a patient's quality of life (QoL), particularly in relation to physical functioning and the ability to perform activities of daily living, is both profound and pervasive. In addition, CRF is associated with considerable psychological distress and can impose a significant financial burden by limiting a patient's ability to work. These effects can extend to caregivers and family members, who may also have to reduce their working capacity in order to provide additional care for a patient with CRF. This paper examines the prevalence of CRF and explores the impact of this distressing symptom on patients' functioning and QoL.
Disclosure of potential conflicts of interest is found at the end of this article.
Integrative Nonpharmacologic Behavioral Interventions for the Management of Cancer-Related Fatigue
Authors: Mustian Karen M. , Morrow Gary R. , Carroll Jennifer K. , Figueroa-Moseley Colmar D. , Jean-Pierre Pascal , Williams Geoffrey C. 
Published: June 2007

Abstract
Cancer-related fatigue (CRF) is a debilitating, multi-faceted biopsychosocial symptom experienced by the majority of cancer survivors during and after treatment. CRF begins after diagnosis and frequently persists long after treatments end, even when the cancer is in remission. The etiological pathopsychophysiology underlying CRF is multifactorial and not well delineated. Mechanisms may include abnormal accumulation of muscle metabolites, dysregulation of the homeostatic status of cytokines, irregularities in neuromuscular function, abnormal gene expression, inadequate ATP synthesis, serotonin dysregulation, abnormal vagal afferent nerve activation, as well as an array of psychosocial mechanisms, including self-efficacy, causal attributions, expectancy, coping, and social support. An important first step in the management of CRF is the identification and treatment of associated comorbidities, such as anemia, hypothyroidism, pain, emotional distress, insomnia, malnutrition, and other comorbid conditions. However, even effective clinical management of these conditions will not necessarily alleviate CRF for a significant proportion of cancer survivors. For these individuals, intervention with additional therapeutic modalities may be required. The National Comprehensive Cancer Network guidelines recommend that integrative nonpharmacologic behavioral interventions be implemented for the effective management of CRF. These types of interventions may include exercise, psychosocial support, stress management, energy conservation, nutritional therapy, sleep therapy, and restorative therapy. A growing body of scientific evidence supports the use of exercise and psychosocial interventions for the management of CRF. Research on these interventions has yielded positive outcomes in cancer survivors with different diagnoses undergoing a variety of cancer treatments. The data from trials investigating the efficacy of other types of integrative nonpharmacologic behavioral therapies for the management of CRF, though limited, are also encouraging. This article provides an overview of current research on the relative merits of integrative nonpharmacologic behavioral interventions for the effective clinical management of CRF and makes recommendations for future research.
Disclosure of potential conflicts of interest is found at the end of this article.
Search methods that people use to find owners of lost pets
Authors: Lord Linda K. , Wittum Thomas E. , Ferketich Amy K. , Funk Julie A. , Rajala-Schultz Päivi J. 
Published: June 2007

Abstract
Objective—To characterize the process by which people who find lost pets search for the owners.
Design—Cross-sectional study.
Sample Population—188 individuals who found a lost pet in Dayton, Ohio, between March 1 and June 30, 2006.
Procedures—Potential participants were identified as a result of contact with a local animal agency or placement of an advertisement in the local newspaper. A telephone survey was conducted to identify methods participants used to find the pets' owners.
Results—156 of 188 (83%) individuals completed the survey. Fifty-nine of the 156 (38%) pets were reunited with their owners; median time to reunification was 2 days (range, 0.5 to 45 days). Only 1 (3%) cat owner was found, compared with 58 (46%) dog owners. Pet owners were found as a result of information provided by an animal agency (25%), placement of a newspaper advertisement (24%), walking the neighborhood (19%), signs in the neighborhood (15%), information on a pet tag (10%), and other methods (7%). Most finders (87%) considered it extremely important to find the owner, yet only 13 (8%) initially surrendered the found pet to an animal agency. The primary reason people did not surrender found pets was fear of euthanasia (57%). Only 97 (62%) individuals were aware they could run a found-pet advertisement in the newspaper at no charge, and only 1 person who was unaware of the no-charge policy placed an advertisement.
Conclusions and Clinical Relevance—Veterinarians and shelters can help educate people who find lost pets about methods to search for the pets' owners.
Comparison of three methods of temperature measurement in hypothermic, euthermic, and hyperthermic dogs
Authors: Greer Rebecca J. , Cohn Leah A. , Dodam John R. , Wagner-Mann Colette C. , Mann F. A. 
Published: June 2007

Abstract
Objective—To assess the reliability and accuracy of a predictive rectal thermometer, an infrared auricular thermometer designed for veterinary use, and a subcutaneous temperature-sensing microchip for measurement of core body temperature over various temperature conditions in dogs.
Design—Prospective study.
Animals—8 purpose-bred dogs.
Procedures—A minimum of 7 days prior to study commencement, a subcutaneous temperature-sensing microchip was implanted in 1 of 3 locations (interscapular, lateral aspect of shoulder, or sacral region) in each dog. For comparison with temperatures measured via rectal thermometer, infrared auricular thermometer, and microchip, core body temperature was measured via a thermistor-tipped pulmonary artery (TTPA) catheter. Hypothermia was induced during anesthesia at the time of TTPA catheter placement; on 3 occasions after placement of the catheter, hyperthermia was induced via administration of a low dose of endotoxin. Near-simultaneous duplicate temperature measurements were recorded from the TTPA catheter, the rectal thermometer, auricular thermometer, and subcutaneous microchips during hypothermia, euthermia, and hyperthermia. Reliability (variability) of temperature measurement for each device and agreement between each device measurement and core body temperature were assessed.
Results—Variability between duplicate near-simultaneous temperature measurements was greatest for the auricular thermometer and least for the TTPA catheter. Measurements obtained by use of the rectal thermometer were in closest agreement with core body temperature; for all other devices, temperature readings typically underestimated core body temperature.
Conclusions and Clinical Relevance—Among the 3 methods of temperature measurement, rectal thermometry provided the most accurate estimation of core body temperature in dogs.