bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production and Characterization of a Novel Tissue‐Type Plasminogen Activator Derivative in Escherichia coli
Authors: Saito Yoshimasa , Ishii Yoshinori , Sasaki Hitoshi , Hayashi Masako , Fujimura Takao , Imai Yuko , Nakamura Sachiko , Suzuki Shingo , Notani Joji , Asada Takashi , Horiai Haruo , Kobayashi Masakazu , Niwa Mineo 
Published: March 2005

AbstractWe have created a novel thrombolytic agent by the combination of mutation with partial deletion of tissue‐type plasminogen activator (t‐PA). We constructed Escherichia coli expression vectors for (i) native t‐PA (nt‐PA) and its derivatives; (ii) K1K2P, consisting of kringle 1 (K1), kringle 2 (K2), and protease (P) domains; (iii) K2P, consisting of K2 and P domains; (iv) D‐nt‐PA, (v) D‐K1K2P; and (vi) D‐K2P. The latter three are point mutants of nt‐PA, K1K2P, and K2P, respectively, in which Arg275 (number corresponds to that of nt‐PA) has been mutated to Asp. The production of nt‐PA and its derivatives was remarkably improved by (i) removal of the 3× noncoding region of nt‐PA cDNA from expression vectors and (ii) expression in mutant E. coliderived from E. coli HB101, which is insensitive to heat‐shock inductions. The proteins produced were precipitated as insoluble aggregates in the cells and were renatured to active forms by extraction with 8 M urea followed by dialysis against a redox buffer containing GSH and GSSG. The renaturation yield depended on the pH of the buffer and the number of disulfide bonds of the proteins (nt‐PA ≪ K1K2P < K2P). The mutation of Arg275 (the plasmin cleavage site) caused an increase in the catalytic enhancement by fibrin and a decrease of the interaction with plasminogen activator inhibitors. Among them, D‐K2P was selected as a candidate for a new thrombolytic agent because of (i) its facility of renaturation and purification to homogeneity and (ii) its high catalytic enhancement by fibrin, as compared with nt‐PA or other derivatives produced by the same system. It was produced in large amounts and characterized by structural analysis, as well as by biological and pharmacological activities. The disulfide linkages of D‐K2P were found to be identical to those of nt‐PA (Bowes) on the kringle 2 and protease domains. Although its specific activity is approximately one‐fourth that of nt‐PA (Bowes), it shows higher fibrin acceleration and a longer half‐life in blood than nt‐PA (Bowes). In the preliminary pharmacological studies, D‐K2P exhibited more potential thrombolytic effect than recombinant nt‐PA (alteplase) by both bolus and infusional administrations in the rabbit thrombus model. It was also more effective in canine coronary thrombosis. These results may indicate that plasma half‐life and fibrin acceleration play important roles in the thrombolytic agent.
Partitioning of Vancomycin Using Poly(ethy1ene glycol)‐Coupled Ligands in Aqueous Two‐Phase Systems
Authors: Singh Manish , Clark William M. 
Published: March 2005

AbstractAffinity partitioning describes a process in which a biospecific ligand is used to manipulate the partitioning behavior of a biomolecule by coupling a ligand to one of the phase‐forming polymers. It combines the high selectivity of affinity chromatography with the scalability of aqueous two‐phase extractions. Fundamental studies have been made on the factors affecting affinity partitioning of the antibiotic vancomycin using a series of polymer—ligands composed of the D‐Ala‐D‐Ala peptide coupled to poly(ethy1ene glycol) in methoxypoly(ethy1ene g1ycol)/dextran aqueous two‐phase systems. The effects of varying the ligand molecular weight, the ligand binding interaction, the number of binding sites, the tie‐line length, and the aggregation of vancomycin have been measured. A modification of the Flanagan and Barondes model for affinity partitioning has been suggested to explain the results. The modified model accounts for the changes in the surface properties of the biomaterial on complex formation.
A Dynamic Light Scattering Study of β‐Galactosidase: Environmental Effects on Protein Conformation and Enzyme Activity
Authors: Yang Shang‐Tian , Marchio Jack L. , Yen Jyh‐Wen 
Published: March 2005

AbstractDynamic light scattering (DLS) is a useful technique for analyzing the size, shape, and other structural characteristics of protein molecules in solution. The effects of various environmental conditions on the structure and activity of Aspergillus oryzae β‐galactosidase were studied. DLS was used to determine protein particle size under various salt, pH, and temperature conditions. Changes in the activity and stability of this enzyme caused by different environmental conditions were found to correlate well with the size changes of the protein particles. This change in protein size can be attributed to protein unfolding and aggregation under extreme conditions. The presence of the enzyme substrate, lactose, in the protein solution greatly enhanced enzyme stability by inhibiting aggregation.
Effects of Solution Properties on Solute and Permeate Flux in Bovine Serum Albumin‐IgG Ultrafiltration
Authors: Nel Russell G. , Oppenheim S. F. , Rodgers V. G. J. 
Published: March 2005

AbstractIt has been observed that bovine serum albumin (BSA, 69 000 Da) exhibits high rejection in a pH 7.4, 0.15 M NaCl solution containing low concentrations of immuno‐γ‐globulins (IgG, 155000 Da). Although it is apparent that this phenomenon is likely due to the complex interactions of the proteins as well as to simple steric hindrance, it is not clear to what extent these resistances contribute to the solute flux loss. This study investigates how variations in IgG concentration, solution pH, and ionic strength can affect the solute and the permeate fluxes for the ultrafiltration of BSA through 100 000 MWCO cellulosic membranes in a batch cell. The results showed that, unlike cases performed at pH 7.4 in 0.15 M NaCl, the presence of IgG may increase the transport of BSA under certain conditions. This study does show the potential value and insights that will result from further binary protein ultrafiltration research.
Resemblance of Immobilized Trichoderma viride Fungal Spores in an Alginate Matrix to a Composite Material
Authors: Nussinovitch A. 
Published: March 2005

AbstractTrichoderma uiride fungal spores were immobilized in alginate gels. The mechanical properties of these gels were tested by compression using a universal testing machine. The properties of the immobilized preparations are presented in terms of their corrected stress at failure, Hencky's strain at failure, and the modulus of deformability. Results are also presented as the ratio between mechanical properties of gels with or without microorganisms, and the occupied volume of the tested gel. A simple mathematical model for composite materials was found to properly describe the relative stress at failure vs the phase volume of the fungal spores. Random loose packing of the spores in the matrix is proposed.
Tetanic Stimulation of the Peripheral Nerve before Transcranial Electrical Stimulation Can Enlarge Amplitudes of Myogenic Motor Evoked Potentials during General Anesthesia with Neuromuscular Blockade
Authors: Kakimoto Meiko , Kawaguchi Masahiko , Yamamoto Yuri , Inoue Satoki , Horiuchi Toshinori , Nakase Hiroyuki , Sakaki Toshisuke , Furuya Hitoshi 
Published: March 2005

Background
Neuromuscular blockade can suppress myogenic motor evoked potentials (MEPs). The authors hypothesized that tetanic stimulation (TS) of the peripheral nerve before transcranial stimulation may enhance myogenic MEPs during neuromuscular blockade. In the current study, the authors evaluated MEP augmentations by TS at different levels of duration, posttetanic interval, neuromuscular blockade, and stimulus intensity.

Methods
Thirty-two patients undergoing propofol-fentanyl-nitrous oxide anesthesia were examined. Train-of-five stimulation was delivered to C3-C4, and MEPs were recorded from the abductor hallucis muscle. In study 1, TS with a duration of 1, 3, or 5 s was delivered at 50 Hz to the tibial nerve 1, 3, or 5 s (interval) before transcranial stimulation, and the effects of TS on MEP amplitude were evaluated. In study 2, TS-induced MEP augmentations were evaluated at the neuromuscular blockade level (%T1) of 50% or 5%. In study 3, MEP augmentations by TS at stimulus intensities of 0, 5, 25, and 50 mA were evaluated.

Results
The application of TS significantly enlarged the amplitudes of MEPs at the combinations of duration (3, 5 s) and interval (1, 3, 5 s) compared with those without TS. TS-induced MEP augmentations were similarly observed at %T1 of both 50% and 5%. TS-induced MEP augmentations were observed at stimulus intensities of 25 and 50 mA.

Conclusions
The results indicate that TS of the peripheral nerve before transcranial stimulation can enlarge the amplitude of MEPs during general anesthesia with neuromuscular blockade. TS of the peripheral nerve can be intraoperatively applied as a method to augment myogenic MEP responses.
Does Preoperative Coronary Angioplasty Improve Perioperative Cardiac Outcome?
Authors: Godet Gilles , Riou Bruno , Bertrand Michèle , Fléron Marie-Hélène , Goarin Jean-Pierre , Montalescot Gilles , Coriat Pierre 
Published: March 2005

Background
Percutaneous coronary intervention (PCI) is performed in patients with coronary artery disease who are undergoing major noncardiac procedures to reduce perioperative cardiac morbidity and mortality. However, the impact of this approach on postoperative outcome remains controversial.

Methods
The authors analyzed a cohort of 1,152 patients after abdominal aortic surgery in which 78 patients underwent PCI. A propensity score analysis was performed. Also, using a logistic regression model, the authors determined variables associated with a severe postoperative coronary event or a death in patients without PCI. Then, in patients with PCI, they compared the expected and observed outcome.

Results
Five variables (age > 75 yr, blood transfusion > 3 units, repeated surgery, preoperative hemodialysis, and previous cardiac failure) independently predicted (with 94% correctly classified) a severe postoperative coronary event, and five variables (age > 75 yr, repeated surgery, previously abnormal ST segment/T waves, previous hypertension, and previous cardiac failure) independently predicted (with 97% correctly classified) postoperative death. In the PCI group, the observed percentages of patients with a severe postoperative coronary event (9.0% [95% confidence interval, 4.4-17.4]) or death (5.1% [95% confidence interval, 2.0-12.5]) were not significantly different from the expected percentages (8.2 and 6.9%, respectively). When all patients were pooled together, the odds ratios of PCI were not significant. The propensity score analysis provided a similar conclusion.

Conclusion
PCI did not seem to limit significantly cardiac risk or death after aortic surgery.
Spinal Glucocorticoid Receptors Contribute to the Development of Morphine Tolerance in Rats
Authors: Lim Grewo , Wang Shuxing , Zeng Qing , Sung Backil , Mao Jianren 
Published: March 2005

Background
Opioid analgesic tolerance is a pharmacologic phenomenon involving the mechanisms of cellular adaptation. Central glucocorticoid receptors (GRs) have been implicated in the cellular mechanism of neuronal plasticity that has many cellular steps in common with the mechanism of opioid tolerance. In a rat model of morphine tolerance, the authors examined the hypothesis that spinal GRs would play a significant role in the development of tolerance to the antinociceptive effect of morphine.

Methods
In experiment 1, each group of rats received the GR antagonist RU38486 (0.5 or 1 microg), the mineralocorticoid receptor antagonist spironolactone (3 microg), or a vehicle, given intrathecally with morphine (10 microg) twice daily for 6 days. In experiment 2, four groups of rats were used, and each group received intrathecally 10 microg morphine plus 5 micromol GR antisense oligodeoxynucleotide, sense oligodeoxynucleotide, mixed-base oligodeoxynucleotide, or vehicle. Western blotting was used to examine the expression of GRs within the spinal cord dorsal horn. In experiment 3, the GR agonist dexamethasone (4 microg) was given intrathecally twice daily in combination with 10 microg morphine. For all experiments, the development of morphine antinociceptive tolerance was assessed using the tail-flick test.

Results
The development of tolerance to the antinociceptive effect of morphine was substantially attenuated when the GR antagonist RU38486 (1 > 0.5 microg > vehicle) but not spironolactone was coadministered with morphine for 6 days. A single treatment with RU38486 did not affect morphine antinociception, nor did it reverse morphine tolerance on day 7. A similar reduction of morphine tolerance was observed in those rats treated with a GR antisense oligodeoxynucleotide but not a sense or mixed-base oligodeoxynucleotide. The administration of the GR antisense oligodeoxynucleotide also prevented GR up-regulation within the spinal cord dorsal horn. Moreover, the GR agonist dexamethasone facilitated the development of morphine tolerance.

Conclusions
The results indicate an important role of spinal GRs in the cellular mechanisms of morphine tolerance in rats and may have significant implications in clinical opioid therapy.
Rapid Determination of 226Ra and Uranium Isotopes in Solid Samples by Fusion with Lithium Metaborate and Alpha Spectrometry
Authors: Bojanowski R. , Radecki Z. , Piekoś R. 
Published: March 2005

A simple and rapid method has been developed to determine226Ra in rocks, soils, and sediments. Samples are decomposed by fusion with lithium metaborate and the melt is dissolved in a solution containing sulfates and citric acid. During the dissolution, a fine suspension of mixed barium and radium sulfates is formed. The microcrystals are collected on a membrane filter (pore size 0.1 μm) and analysed in an alpha spectrometer. Application of a133Ba tracer enables us to assess the loss of the analyte, which only rarely exceeds 10%. All analytical operations, beginning from sample decomposition to source preparation for alpha spectrometry, can be accomplished within 1 or 2 h.With uranium determination, the filtrate is spiked with a232U tracer and passed through a column loaded with a Dowex AG (1 x 4) anion-exchange resin in the sulfate form. Interfering elements are eluted with dilute sulfuric acid followed by concentrated hydrochloric acid. Uranium is eluted with water, electrodeposited on silver discs, and analysed in the alpha spectrometer. The method was tested on reference soil and sediment materials and was found to be accurate within the estimated uncertainties.
Role of resistant Drh1 locus in chemical carcinogen‐induced hepatocarcinogenesis in rats: Analysis with a speed congenic strain
Authors: Liu Hongbo , Higashi Ken , Hiai Hiroshi 
Published: March 2005

The DRH is an inbred rat strain established by selective mating of the 3′‐Me‐DAB resistant progeny of closed colony Donryu rats over 20 generations. Genetic analysis shows that two semidominant QTLs, Drh1 and Drh2, are responsible for strong resistance to chemical‐induced hepatocarcinogenesis in DRH strain rats. To evaluate the effect of the single Drh1 locus on various stages of liver carcinogenesis, we constructed a speed congenic strain DRH.F344‐Drh1 by transferring a susceptible Drh1 allele of F344 to DRH rats by marker‐assisted backcrossing. The DRH.F344‐Drh1 rats had a ∼43 cM segment of chromosome 1 bearing Drh1 but the Drh2 was of the DRH allele. After oral administration of 3′‐Me‐DAB for 8 weeks, DRH.F344‐Drh1 had as many enzyme altered foci as F344, whereas the quantitative parameters of fibrosis, enzyme altered foci, GST‐P expression and proliferation of liver cells in DRH.F344‐Drh1 rats were intermediate between F344 and DRH. In the liver of carcinogen‐fed DRH rats, there was intensive apoptosis as detected by TUNEL stain, but not in the liver of F344 and DRH.F344‐Drh1 rats. Injection of lead nitrate (100 µmol/kgB.W) induced a wave of liver cell proliferation, as seen by BrdU uptake within a few days in F344 and DRH.F344‐Drh1 rats, but not in DRH rats. Instead, there were numerous TUNEL‐positive nuclei in the DRH liver after lead nitrate injection. Apparently, the hepatocytes were removed by apoptosis during transition from G0 to G1. The major role of Drh1 is effective removal of the hepatocytes newly recruited to proliferate after chemical injury. Resistance to preneoplastic lesions in DRH rats may well be based on similar mechanism. (Cancer Sci 2005; 96: 164–169)
Performance of young people with Down syndrome on the Leiter‐R and British picture vocabulary scales
Authors: Glenn S. , Cunningham C. 
Published: March 2005

AbstractBackground  The British picture vocabulary scales (BPVS‐II) and the Leiter international performance scales (Leiter‐R), both restandardised in 1997, are often used in experimental studies to match individuals with intellectual impairment. Both provide a brief measure of mental age, and cover a wide ability range using a simple format. The BPVS‐II assesses verbal comprehension and the Leiter nonverbal abilities. The issue is which to choose. People with Down syndrome (DS), for example, have particular problems in language and so the BPVS may provide an underestimation of ability.Method  The present study investigated this by comparing the performance of 46 young people with DS (21 females, 25 males, mean age 19 years 10 months) on the BPVS‐II (verbal mental age – VMA) and the Leiter‐R brief IQ (nonverbal mental age – NVMA).Results  Contrary to expectations VMAs were significantly higher than NVMAs (6 years 6 months and 5 years 2 months, respectively). There was a significant correlation of 0.61 between the VMA and NVMA, and both discriminated participants at all levels of ability. However, the Leiter‐R brief IQ scores provided poor discrimination at the bottom end of the IQ range (IQ 36).Conclusion  Both the BPVS‐II and the Leiter‐R provide mental age equivalent scores that are useful for plotting developmental progress, although absolute mental ages may differ.
The association between environmental events and self‐injurious behaviour in Cornelia de Lange syndrome
Authors: Moss J. , Oliver C. , Hall S. , Arron K. , Sloneem J. , Petty J. 
Published: March 2005

AbstractBackground  There has been limited empirical research into the environmental causes of self‐injury in Cornelia de Lange syndrome. The present study examined the variability of self‐injurious behaviour in Cornelia de Lange syndrome across environmental setting events. Additionally, the association between setting events and more specific environmental events was examined.Method  A descriptive analysis of observational data on eight children with Cornelia de Lange syndrome aged between 4 and 14 years was carried out. The association between self‐injurious behaviour and four environmental setting events and between specific environmental events and setting events was examined using established statistical methods for observational data.Results  Seven out of eight of the participants showed at least one form of self‐injurious behaviour that was associated with a particular setting event. The study also demonstrated that the relationship between setting events and environmental events is extremely variable across individuals.Conclusions  Self‐injurious behaviour in some individuals with Cornelia de Lange syndrome is associated with environmental events although the precise nature of the association warrants clarification. Using broad setting events as a methodological tool in isolation provides some insight into the role of specific environmental factors in maintaining self‐injurious behaviour but the integrity of setting events must be established.
Detecting Holocene divergence in the anadromous–freshwater three‐spined stickleback (Gasterosteus aculeatus) system
Authors: RAEYMAEKERS J. A. M. , MAES G. E. , AUDENAERT E. , VOLCKAERT F. A. M. 
Published: March 2005

AbstractThe anadromous–freshwater three‐spined stickleback (Gasterosteus aculeatus) system allows for inferring the role of adaptation in speciation with a high level of accuracy because the freshwater ecotype has evolved multiple times from a uniform anadromous ancestor. A cause for concern is that independent evolution among drainages is not guaranteed in areas with a poorly resolved glacial history. This is the case for the west European great rivers, whose downstream valleys flanked the southern limit of the late Pleistocene ice sheet. We tested for independent and postglacial colonization of these valleys hypothesizing that the relationships among anadromous and freshwater sticklebacks correspond to a raceme structure. We compared the reduction in plate number accompanying this colonization to the genetic differentiation using 13 allozyme and five microsatellite loci in 350 individuals. Overall microsatellite differentiation (FST = 0.147) was twice as large as allozyme differentiation (FST = 0.066). Although habitat‐specific gene flow may mask the ancestral relationships among both ecotypes, levels of microsatellite differentiation supported the hypothesis of raceme‐like divergence, reflecting independent colonizations rather than the presence of two distinct evolutionary clades. Under an infinite alleles model and in the absence of gene flow, the observed freshwater divergence might be reached after 440 (microsatellites) to 4500 (allozymes) generations. Hence, the anadromous–freshwater stickleback system most likely diverged postglacially. We conclude that the reduction in plate number in two freshwater basins probably occurred independently, and that its considerable variation among populations is not in agreement with the time since divergence.
A Signal for Independent Coastal and Continental histories among North American wolves
Authors: WECKWORTH BYRON V. , TALBOT SANDRA , SAGE GEORGE K. , PERSON DAVID K. , COOK JOSEPH 
Published: March 2005

AbstractRelatively little genetic variation has been uncovered in surveys across North American wolf populations. Pacific Northwest coastal wolves, in particular, have never been analysed. With an emphasis on coastal Alaska wolf populations, variation at 11 microsatellite loci was assessed. Coastal wolf populations were distinctive from continental wolves and high levels of diversity were found within this isolated and relatively small geographical region. Significant genetic structure within southeast Alaska relative to other populations in the Pacific Northwest, and lack of significant correlation between genetic and geographical distances suggest that differentiation of southeast Alaska wolves may be caused by barriers to gene flow, rather than isolation by distance. Morphological research also suggests that coastal wolves differ from continental populations. A series of studies of other mammals in the region also has uncovered distinctive evolutionary histories and high levels of endemism along the Pacific coast. Divergence of these coastal wolves is consistent with the unique phylogeographical history of the biota of this region and re‐emphasizes the need for continued exploration of this biota to lay a framework for thoughtful management of southeast Alaska.