bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations of dose and electrode spacing for rat breast cancer electrochemical treatment
Authors: Ren Ru‐Long , Vora Nayana , Yang Frank , Longmate Jeff , Wang Warner , Sun Helen , Li Jian‐Ren , Weiss Lawrence , Staud Cecil , McDougall John A. , Chou Chung‐Kwang 
Published: August 2002

AbstractElectrochemical treatment (EChT) with direct current delivered through implanted electrodes has been used for local control of solid tumors in humans. This study tested the hypothesis that rat breast cancer responses to EChT are dependent on electrode spacing and dose, and explored suitable parameters for treating breast cancers with EChT. Rat breast cancers were initiated by injecting 1 × 106 MTF‐7 cells to the right mammary gland fat pad of Fisher 344 female rats. The rats were randomly divided into designated experimental groups when the tumors grew to approximately 2 × 2 × 2 cm. One hundred and thirty rats were used for a survival study and 129 for a pathology study. A 4‐channel EChT machine was used to administer coulometric doses. The survival study indicated that local tumor control rate is less than 40% in the 40 coulomb (C) and 60 C groups and more than 70% in the 80 and 100 C groups. Sixty six rats died of primary tumors, including all 10 rats in the control group. Once a rat's primary tumor was controlled, no recurrence was found. The main reason for terminating the primary tumor‐free rats (51) was lymph node metastasis. Thirteen tumor‐free rats survived for more than 6 months. The pathology study showed a significant dose effect on EChT induced tumor necrosis. At 10, 20, 40, and 80 C, the fraction showing necrosis were 39.7, 52.3, 62, and 77.7%, respectively (P ≤ 0.001). Electrodes spacing was not an important factor within a given range. At 5, 10, and 15 mm spacing, the fraction showing the necrosis were 54.1, 60.4, and 59.2%, respectively (P = 0.552). The overlap rate of necroses was similar in the 5 and 10 mm groups (82.5 and 85%) and lower in the 15 mm group (65%). We conclude that the tumor responses to EChT, local control, survival rates, and necrosis percentages were significantly increased with increasing dose. The changes in electrode spacing (3, 5, and 10 mm) did not significantly affect the tumor responses to EChT within the same dose. For a diameter of 2.0–2.5 cm rat breast cancer, EChT should be applied with 5–10 mm spacing and a minimum dosage of 80 C. Bioelectromagnetics 22:205–211, 2001. © 2001 Wiley‐Liss, Inc.
Effects of 50 Hz magnetic field on cell cycle kinetics and the colony forming ability of budding yeast exposed to ultraviolet radiation
Authors: Markkanen Ari , Juutilainen Jukka , Lang Sakari , Pelkonen Jukka , Rytömaa Tapio , Naarala Jonne 
Published: August 2002

AbstractTo investigate the effects of extremely low frequency magnetic fields on ultraviolet radiation (UV) exposed budding yeast, haploid yeast (Saccharomyces cerevisiae) cells of the strain SEy2101a were exposed to 50 Hz sine wave magnetic field (MF) of 120 μT with simultaneous exposure to UV radiation. Most of the UV energy was in the UVB range (280–320 nm). The biologically weighted (CIE action spectrum) dose level for the UV radiation was 175 J/m2. We examined whether 50 Hz MF affected the ability of UV irradiated yeast cells to form colonies (Colony Forming Units, CFUs). In addition, the effect of coexposure on cell cycle kinetics was investigated. Although the significant effect of MF on the cell cycle phases of UV exposed yeast cells was seen only at one time point, the overall results showed that MF exposure may influence the cell cycle kinetics at the first cycle after UV irradiation. The effect of our particular MF exposure on the colony forming ability of the UV irradiated yeast cells was statistically significant 420 min after UV irradiation. Moreover, at 240, 360, and 420 min after UV irradiation, there were fewer CFUs in every experiment in (UV+MF) exposed populations than in only UV exposed yeast populations. These results could indicate that MF exposure in conjunction with UV may have some effects on yeast cell survival or growth. Bioelectromagnetics 22:345–350, 2001. © 2001 Wiley‐Liss, Inc.
Mechanism of the fluorescent light induced suppression of Curly phenotype in Drosophila melanogaster
Authors: Pavelka Jaroslav , Jindrák Libor 
Published: August 2002

AbstractA dominant mutation Curly (Cy), frequently used as a marker on the second chromosome in Drosophila melanogaster, was previously shown to be suppressed by several factors, including larval crowding, low temperature, and fluorescent light. While the first two factors affect this mutation only partially, fluorescent tube exposed flies exhibit an almost completely suppressed (wild type) phenotype. This suppressive effect is the result of a combination of the electric field and light, both factors being produced by common fluorescent tubes. In this study, experiments were carried out to clarify the basic mechanism of this unique phenomenon. Two fluorescent tube sensitive stages of Drosophila development were found in the second half of embryonic development and first half of the pupal stage. Riboflavin, which is administered to Drosophila larvae with yeast, and decomposed by light, seems to play a key role in this phenomenon. In a medium lacking riboflavin caused by light exposure, Cy expression is inhibited by the action of electric field. Positive results of experiments with lithium ions, which block the opening of Ca2+ channels, support the hypothesis that electromagnetic fields may alter ion currents during ontogenic development of Drosophila, and thus influence, expression of the Cy gene. Also, fluorescent light induces an overexpression of a specific protein in the imaginal wing disc of Cy pupae. Bioelectromagnetics 22:371–383, 2001. © 2001 Wiley‐Liss, Inc.
Influence of intestinal myoelectrical activity on the growth of Escherichia coli
Authors: Grzesiuk Elżbieta , Laubitz Daniel , Wójcik‐Sikora Anna , Zabielski Romuald , Pierzynowski Stefan G. 
Published: August 2002

AbstractIntestinal bacteria, particularly those adhering to intestinal epithelial cells, are exposed to electric fields and currents generated by the muscular activity of the small intestine. This activity displays a regular pattern known as the myoelectrical migrating complex (MMC). In order to explore the possibility that these endogenous electric fields could affect bacterial growth, a digitised duodenal signal obtained via serosal electrodes from a healthy calf was recorded and then applied via platinum electrodes to Escherichia coli cultures. The culture tubes were placed within a Faraday shield, incubated at 37°C with shaking, and stimulated by the electric current for 5 or 8 h. The growth of E. coli stimulated by the electric current was significantly altered compared to those of non‐stimulated controls: after a period of intensive growth, inhibition of cell division was observed. This was not the case when the bacteria with lon mutation were used. Moreover, synchronic bacterial culture could not be achieved in the presence of the MMC‐related electric field. These results suggest that the myoelectrical activity of the duodenum, through action on cell membrane, can affect cell division of intestinal bacteria. Bioelectromagnetics 22:449–455, 2001. © 2001 Wiley‐Liss, Inc.
Spider flagelliform silk: lessons in protein design, gene structure, and molecular evolution
Authors: Hayashi Cheryl Y. , Lewis Randolph V. 
Published: August 2002

AbstractSpiders spin multiple types of silks that are renowned for their superb mechanical properties. Flagelliform silk, used in the capture spiral of an orb‐web, is one of the few silks characterized by both cDNA and genomic DNA data. This fibroin is composed of repeating ensembles of three types of amino acid sequence motifs. The predominant subrepeat, GPGGX, likely forms a β‐turn, and tandem arrays of these turns are thought to create β‐spirals. These spring‐like helices may be critical for the exceptional ability of capture silk to stretch and recoil. Each ensemble of motifs was found to correspond to a different exon within the flagelliform gene. The pattern of sequence similarity among exons indicates intragenic concerted evolution. Surprisingly, the introns between the iterated exons are also homogenized with each other. This unusual molecular architecture in the flagelliform silk gene has implications for the evolution and maintenance of spider silk proteins. BioEssays 23:750–756, 2001. © 2001 John Wiley & Sons, Inc.
Shaping the metaphase chromosome: coordination of cohesion and condensation
Authors: Losada Ana , Hirano Tatsuya 
Published: August 2002

AbstractRecent progress in our understanding of mitotic chromosome dynamics has been accelerated by the identification of two essential protein complexes, cohesin and condensin. Cohesin is required for holding sister chromatids (duplicated chromosomes) together from S phase until the metaphase‐to‐anaphase transition. Condensin is a central player in chromosome condensation, a process that initiates at the onset of mitosis. The main focus of this review is to discuss how the mitotic metaphase chromosome is assembled and shaped by a precise balance between the cohesion and condensation machineries. We argue that, in different eukaryotic organisms, the balance of cohesion and condensation is adjusted in such a way that the size and shape of the resulting chromosomes are best suited for their accurate segregation. BioEssays 23:924–935, 2001. © 2001 John Wiley & Sons, Inc.
Evaluation of a participatory, competency‐based model of staff training in a community habilitative setting
Authors: Harchik Alan E. , Anderson Michele , Thomson Ron , Forde Keith , Feinberg Lyle , Rivest Stacey , Luiselli James K. 
Published: August 2002

AbstractThis study evaluated a participatory model of staff training within a community habilitative setting for adults with developmental disabilities. The objectives were to formulate an approach to training that was not time intensive, included multiple instructional methods, and incorporated all levels of staff involvement. Senior administrative, middle‐level supervisory, and direct‐care personnel comprised a committee that designed and implemented a training program that targeted performance and verbal report competencies required by ‘on‐line’ staff. Training consisted of corrective feedback, modeling, rehearsal, and practice procedures that were carried out with three individuals in a multiple baseline design across sets of target competencies. The training program was effective in establishing staff competencies although individual learning effects were revealed. The implications of these findings for the design of staff training programs within human service agencies are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Effects of lysophospholipids on the generation of reactive oxygen species by fMLP‐ and PMA‐stimulated human neutrophils
Authors: Müller Julia , Petković Marijana , Schiller Jürgen , Arnold Klaus , Reichl Sabine , Arnhold Jürgen 
Published: August 2002

AbstractIn this study, the effects of exogenous lysophospholipids—lysophosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine and lysophosphatidylserine—on the kinetics of reactive oxygen species (ROS) production by human neutrophils are described. The ROS production by human neutrophils was monitored by luminol‐amplified chemiluminescence after cell stimulation with the chemotactic tripeptide, fMLP, or with the phorbol ester, PMA. The interaction of lysophospholipids with the membrane of human neutrophils was additionally tested by mass spectrometry. Lysophosphatidylcholine showed the most pronounced effect on the chemiluminescence pattern, as well as the intensity of the fMLP and PMA‐stimulated cells, whereas lysophosphatidic acid showed a slight priming effect when fMLP was used for stimulation. In the case of fMLP‐stimulated cells, lysophosphatidylcholine inhibited the first phase and enhanced the second phase of chemiluminescence, whereas the chemiluminescence of PMA‐stimulated neutrophils was inhibited in a concentration‐dependent manner. We conclude that lysophosphatidylcholine is able to interact with protein kinase C‐dependent signalling pathways leading to NADPH oxidase activation. Copyright © 2002 John Wiley & Sons, Ltd.
New Fourier transform infrared based computational method for peptide secondary structure determination. I. Description of method
Authors: Simonetti Mario , Di Bello Carlo 
Published: August 2002

AbstractFourier transform infrared (FTIR) experiments in dimethylsulfoxide, a solvent incapable of H donation, demonstrate that H → D isotopic replacement on the amide side of peptide bonds involves modifications of both the position and intensity of the amide I band. The effect of the isotopic substitution is particularly significant in the 1710–1670 and 1670–1650 cm−1 regions, which are generally associated with β‐turns and α‐helices. This behavior, attributed to the existence of intramolecular H‐bonds in the polypeptide chain, is directly correlated to the presence of different secondary structures. Utilizing the effects induced by isotopic substitution, a method for the quantitative determination of the percentage of intramolecular H‐bonds and the correlated secondary structures is proposed. The method consists of three principal steps: resolution of the fine structure of the amide I band with the determination of the number and position of the different components; reconstruction of the experimentally measured amide I band as a combination of Gaussian and Lorentzian functions, centered on the wave numbers set by band‐narrowing methods, through a curve‐fitting program; and quantitative determination of the population of the H‐bonded carbonyls and the correlated secondary structures by comparison of the integrated intensities pertaining to the components with homologous wave numbers before and after isotopic exchange. The method is tested on a synthetic fragment of proocytocin that was previously analyzed by NMR techniques using the same solvent systems. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 95–108, 2001
Effects of lipids on elastin's viscoelastic properties
Authors: Lillie M. A. , Gosline J. M. 
Published: August 2002

AbstractSodium dodecyl sulfate (SDS) was used as a model lipid to identify the molecular basis of possible lipid‐induced changes in the viscoelastic behavior of arterial elastin. The chemical composition of the elastin network and the interfibrillar space was calculated from the chemical content of the elastin sample and its swelling behavior. Viscoelastic behavior was measured in aqueous SDS and in SDS plus 1 M sucrose, a deswelling agent. Viscoelastic behavior was also measured in sucrose and potassium thiocyanate solutions to identify the effects of swelling and of changes in network composition exclusive of any direct SDS effects. The hydration of the elastin network decreased at low SDS levels and increased at higher SDS levels. The elastin was stiffer in the dehydrated network and less stiff in the hydrated network. However, once the degree of hydration exceeded that of elastin in pure water, no further decrease in stiffness was obtained despite continued increase in swelling. The stiffness of the network could be accounted for entirely by changes in network hydration. There was no evidence that SDS had any effect on elastin's conformation. We predict that arterial lipids will interact with elastin in a similar way and will have only small effects on elastin's viscoelastic behavior. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 127–138, 2002
Static and dynamic light scattering approach to the hydration of hemoglobin and its supertetramers in the presence of osmolites
Authors: Arosio Daniele , Kwansa Herman E. , Gering Henry , Piszczek Grzegorz , Bucci Enrico 
Published: August 2002

AbstractWe used static and dynamic light scattering for comparing the mass (MW) and hydrodynamic radius (Rh) of several hemoglobin systems, namely human hemoglobin, bovine hemoglobin, human hemoglobin cross‐linked with a sebacyl residue, and bovine hemoglobin cross‐linked with an adipoyl residue. We measured the MW and Rh of these systems in 0.1M phosphate buffer at pH 7.0 in the absence and in the presence of either betaine or glycerol up to 1.7 molal concentrations. The 90° scattering was measured with a photon counting machine equipped with a diode laser at 783 nm. The Rayleigh ratio [R(θ)] of the instrument was estimated using R(θ) = 7.19E‐6 cm−1 for toluene at 783 nm. The refractive index increment of hemoglobin solutions was measured using a laser beam at 750 nm. We estimated a value dn/dc = 0.210 cm3/g in the absence and dn/dc = 0.170 in the presence of 1.7 molal osmolites. For all systems both in liganded and unliganded form, the static light scattering data showed a 16% mass increase with increasing concentration of osmolites. The hydrodynamic radii of all investigated systems in the presence and absence of osmolites were close to 3.17 nm. Assuming a partial specific volume ν = 0.739 for hemoglobin, and using spherical geometry, the estimated average hydration volume of hemoglobin was 32.6 L/mole in the absence of osmolites. It decreased to 23.5 L/mole in the presence of 1.7 molal osmolites. Assuming that the density of water in the hydration volume is D = 1.0 g/cm3, the hydration of Hb was 0.51 gH2O/gHb, with a surface density of 0.20 molH2O/Å2. The hydration decreased to 0.33 gH2O/gHb and 0.14 molH2O/Å2 in the presence of 1.7 molal osmolites. The decreased hydration was compensated by the increased mass (i.e., decreased surface area per unit volume) so that the thickness of the water shell around these proteins remained close to a single layer of water molecules. These findings indicate that the combination of static and dynamic light scattering offer unique means for investigating the relevance of water activity on the structure and function of biological macromolecules. In the case of hemoglobin, the data suggest that the decreased oxygen affinity in the presence of osmolites reported by Colombo et al. (M. F. Colombo, D. C. Rau, and V. A. Parsegian Science, 1992, Vol. 256, pp. 655–659), as due to ligand linked water binding on hemoglobin surface, is part of a complex phenomenon involving the hydration shell of hemoglobin and the formation of low affinity supertetrameric molecules. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 1–11, 2002
Multiple stable states and hysteresis in continuous, oscillating cultures of budding yeast
Authors: Zamamiri Abdel‐Qader M. , Birol Gülnur , Hjortsø Martin A. 
Published: August 2002

AbstractThe conditions that precede the onset of autonomous oscillations in continuous yeast cultures were studied in three different types of experiments. It was found that the final state of the culture depended on the protocol used to start up the reactor. Batch cultures, switched to continuous operation at different stages of the batch growth curve, all exhibited similar dynamics—ethanol depletion followed by autonomous oscillations. Small perturbations of the distribution of states in the reactor, achieved by addition of externally grown cells, were able to quench the oscillatory dynamics. Reaching the desired operating point by slow dilution rate changes gave rise to different final states, two oscillatory states and one steady state, depending on the rate of change in dilution rate. The multiplicity of stable states at a single operating point is not explained by any current distributed model and points toward a segregated mechanism of these oscillations. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 305–312, 2001.
Application of redox mediators to accelerate the transformation of reactive azo dyes in anaerobic bioreactors
Authors: van der Zee Frank P. , Bouwman Renske H. M. , Strik David P. B. T. B. , Lettinga Gatze , Field Jim A. 
Published: August 2002

AbstractAzo dyes are nonspecifically reduced under anaerobic conditions but the slow rates at which reactive azo dyes are converted presents a serious problem for the application of anaerobic technology as a first stage in the complete biodegradation of these compounds. As quinones have been found to catalyze reductive transfers by acting as redox mediators, the application of anthraquinone‐2,6‐disulfonic acid (AQDS) during continuous anaerobic treatment of the reactive azo dye, Reactive Red 2 (RR2), was evaluated. A mixture of volatile fatty acids was used as the electron‐donating primary substrate. Batch experiments demonstrated that AQDS could increase the first‐order rate constant of RR2 reductive cleavage by one order of magnitude. In the continuous experiment, treatment of RR2 containing synthetic wastewater in a lab‐scale upflow anaerobic sludge blanket (UASB) reactor yielded low dye removal efficiencies (<30%). Consequently, severe toxicity problems occurred, eventually resulting in almost complete inhibition of the methanogenic activity. Addition of catalytic concentrations of AQDS (19 μM) to the reactor influent caused an immediate increase in the dye removal efficiency and recovery of biological activity. Ultimately, RR2 removal efficiency stabilized at 88%, and higher AQDS loads resulted in higher RR2 removal efficiencies (up to 98% at 155 μM AQDS). Examination of the RR2 decolorizing properties of dye‐adapted reactor sludge and of nonadapted reactor seed sludge revealed that RR2 decolorization was principally a biologically driven transfer of reducing equivalents from endogenous and added substrates to the dye. Hydrogen, added in bulk, was clearly the preferred electron donor. Bacteria that couple dye decolorization to hydrogen oxidation were naturally present in seed sludge. However, enrichment was required for the utilization of electrons from volatile fatty acids for dye reduction. The stimulatory effect of AQDS on RR2 decolorization by AQDS‐unadapted sludge was mainly due to assisting the electron transfer from endogenous substrates in the sludge to the dye. The stimulatory effect of AQDS on RR2 decolorization by sludge from the AQDS‐exposed reactor was, in addition, strongly associated with the transfer of electrons from hydrogen and acetate to the dye, probably due to enrichment of specialized AQDS‐reducing bacteria. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75:691–701, 2001.
The effect of various substrates on cell attachment and differentiation of 3T3‐F442A preadipocytes
Authors: Viravaidya Kwanchanok , Shuler Michael L. 
Published: August 2002

AbstractThe influence of extracellular matrix (Matrigel), collagen, and polylysine substrates on cell attachment and differentiation in 3T3‐F442A preadipocytes was investigated. In comparison to an uncoated‐polystyrene substrate, a concentrated Matrigel substrate (100 μg/cm2) markedly increased intracellular lipid level by about 30%, whereas a lower density Matrigel (10 μg/cm2) accelerated the differentiation rate but did not increase the amount of lipid 21 days after addition of adipogenic factors. Preadipocytes on the collagen surface differentiated less extensively than cells on the polystyrene. Polylysine did not effectively support attachment for either differentiated or undifferentiated cells. These results suggest that Matrigel provides the most suitable environment for both cell adhesion and differentiation for 3T3‐F442A cells. This is in contrast to a previous report that extracellular matrix (from corneal endothelial cells) was detrimental to differentiation of 3T3‐F442A cells. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 454–458, 2002.