Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Interplay”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38Linked to original sources
PubMed2001

The interplay of knowledge and decision making between nurses and doctors in critical care.

This paper explores the complex interrelationships between knowledge and decision making as nurses and doctors interacted with each other in a critical care unit, which comprised a combined general intensive care and cardiothoracic surgical unit. The critical ethnographic study upon which this paper is based, involved a research group of six nurses who worked in the unit. Nurses differentially valued their knowledge, depending on the situation, experience and level of medical input. They were also involved in decision making based on their differential visibility in the process. Nurses' specialised knowledge of the critical care unit played a major role in influencing how they interacted during decision making.

Adult↗
PubMed1989

Interplay of hydrophobic and electrostatic interactions in biopolymer chromatography. Effect of salts on the retention of proteins.

The effect of salt on the retention behavior of proteins in electrostatic and hydrophobic interaction chromatography is described by a three-parameter equation, log k' = A - B log ms + Cms, where k' is the retention factor and ms is the molality of the salt in the eluent. Parameter B, termed the electrostatic interaction parameter, depends on the characteristic charge of the protein and the salt counterion and governs the change of retention with the salt concentration in ion-exchange chromatography. According to the model the magnitude of the hydrophobic interaction parameter C is determined by the hydrophobic contact area upon protein binding at the stationary phase surface and the properties of the salt as measured by its molal surface tension increment. Retention data measured at different salt concentrations in the eluent on a variety of ion exchangers can be fitted to the above equation which yields U-shaped plots of log k' against log ms. The limiting slopes of the appropriate plots at sufficiently low and high salt concentrations can be used to evaluate the electrostatic and hydrophobic interaction parameters, respectively. The approach, which is based on a combination of established treatments of electrostatic and hydrophobic interactions offers a convenient framework for analyzing retention data in biopolymer high-performance liquid chromatography and for the characterization of stationary phases. Furthermore, it may facilitate some characterization of protein molecules on the basis of their retention behavior as a function of the concentration and nature of the salt in the eluent. In the treatment of electrostatic interactions use is made of the counterion condensation theory that is believed to make possible a more comprehensive analysis than the traditional stoichiometric ion-exchange model which assumes binding of the proteins by coulombic interactions at discrete sites. The treatment of hydrophobic interactions is based on an adaptation of the solvophobic theory which predicts that the hydrophobic portion of the free energy of binding is proportional to the hydrophobic contact area and the microthermodynamic surface tension of the aqueous salt solution. Despite its simplicity the theory was successful in explaining the observed effect of the nature and concentration of salt in the eluent, the pH and the effect of the density of fixed charges at the surface of the stationary phase in the absence of specific salt effects.

Biopolymers↗
PubMed2003

Interplay of chromatographic and electrophoretic processes in capillary electrochromatography.

The separation mechanism in capillary electrochromatography (CEC) is a hybrid differential migration process, which entails the features of both high-performance liquid chromatography and capillary zone electrophoresis, i.e., chromatographic retention and electrophoretic migration. The adsorption of the different sample components on the stationary phase can be modified by the presence of the electric field across the column. Here, we use our previously published approach to decouple chromatographic retention from electrophoretic migration that allows us to investigate the "modification" of the retention process in CEC. This paper presents a methodology for characterization of changes in the retention of neutral and charged sample components, under identical conditions of stationary and mobile phase.

Adsorption↗
PubMed1997

The Interplay between Patency, Microsomal Na(+)/K(+) ATPase Activity and Juvenile Hormone, in Tenebrio molitor Parasitized by Hymenolepsis diminuta.

Beetles infected with metacestodes of the rat tapeworm, Hymenolepis diminuta, exhibit reduced fecundity, due to alterations in vitellogenesis. Follicle cell patency is retarded and inefficient vitellogenin uptake ensues. Here, we have reassessed patency and its stimulation by JH III at day 3 post-infection, when the most detrimental changes are observed in other ovarian processes. In Rhodnius prolixus, patency is believed to be brought about by the action of a JH-dependent membrane-bound Na(+)/K(+) ATPase (EC 3.6.1.3); however, this had not been established in Tenebrio molitor. Therefore, the properties of the enzyme, with respect to optimal assay conditions and juvenile hormone dependency, are reported. Maximal stimulation occurred between 50 and 500 nM JH III, a range over which greatest increases in patency were also observed. In infected insects, a 35% reduction in Na(+)/K(+) ATPase activity was noted, but exposure to 50 nM JH III is sufficient for stimulation to a specific activity 89% that of JH-treated controls. In a similar fashion, patency in infected insects is reduced, but can be 'rescued' by 50 nM JH III. Moreover, in the absence of exogenous hormone, patency in infected beetles can be elevated to control levels after in vitro culture (6 h), with exchange of medium every 2 h. The possibility that such reversible decreases in enzyme activity and patency are caused by a JH binding inhibitor molecule is discussed. Copyright 1997 Elsevier Science Ltd. All rights reserved

Journal Article↗
PubMed2003

Interplay among tertiary contacts, secondary structure formation and side-chain packing in the protein folding mechanism: all-atom representation study of protein L.

Experimental and theoretical results suggest that, since proteins are energetically minimally frustrated, the native fold, or topology, plays a primary role in determining the structure of the transition state ensemble and on-pathway intermediate states in protein folding. Although the central role of native state topology in determining the folding mechanism is thought to be a quite general result-at least for small two-state folding proteins-there are remarkable exceptions. Recent experimental findings have shown that topology alone cannot always determine the folding mechanism, and demonstrated that the balance between topology and energetics is very delicate. This balance seems to be particularly critical in proteins with a highly symmetrical native structure, such as proteins L and G, which have similar native structure topology but fold by different mechanisms. Simplified, C(alpha)-atom only protein models have shown not be sufficient to differentiate these mechanisms. An all-atom Gō model provides a valuable intermediate model between structurally simplified protein representations and all-atom protein simulations with explicit/implicit solvent descriptions. We present here a detailed study of an all-atom Gō-like representation of protein L, in close comparison with the experimental results and with the results obtained from a simple C(alpha)-atom representation of the same protein. We also perform simulations for protein G, where we obtain a folding mechanism in which the protein symmetry is broken exactly in the opposite way to protein L as has been observed experimentally. A detailed analysis for protein L also shows that the role of specific residues is correctly and quantitatively reproduced by the all-atom Gō model over almost the entire protein.

Bacterial Proteins↗
PubMed2003

Interplay between DnaA and SeqA proteins during regulation of bacteriophage lambda pR promoter activity.

DnaA and SeqA proteins are main regulators (positive and negative, respectively) of the chromosome replication in Escherichia coli. Nevertheless, both these replication regulators were found recently to be also transcription factors. Interestingly, both DnaA and SeqA control activity of the bacteriophage lambdap(R) promoter by binding downstream of the transcription start site, which is unusual among prokaryotic systems. Here we asked what are functional relationships between these two transcription regulators at one promoter region. Both in vivo and in vitro studies revealed that DnaA and SeqA can activate the p(R) promoter independently and separately rather than in co-operation, however, increased concentrations of one of these proteins negatively influenced the transcription stimulation mediated by the second regulator. This may suggest a competition between DnaA and SeqA for binding to the p(R) regulatory region. The physiological significance of this DnaA and SeqA-mediated regulation of p(R) is demonstrated by studies on lambda plasmid DNA replication in vivo.

Bacterial Outer Membrane Proteins↗
PubMed1999

Graph-theoretic description of the interplay between non-linearity and connectivity in biological systems.

The purpose of this article is to stress the implications that the consideration of nonlinearity has upon the extension and strength of connectivity, if this is understood as a characterization of the degree of interrelation between parts of the system. This objective is reached within the QP formalism for non-linear ODEs. The formalism is developed in a graph-theoretic setting, with the help of which the connectionist aspect of non-linearity becomes apparent. Topology-preserving transformations involve an exchange between the degree of non-linearity and the strengths of interactions, thus assembling systems of apparently different nature into classes of equivalence. We argue that, if we have in mind a classification of systems according to behavior, these classes of equivalence should be given their proper singularity. We characterize globally the connectivity of a class with an index, although we point out during the discussion that the mathematical conception of the complex idea of connectivity is still incomplete.

Linear Models↗
PubMed2001

The process of aging changes the interplay of the immune, endocrine and nervous systems.

The immune, endocrine and nervous systems interact with each other by means of cytokines, hormones and neurotransmitters. Interaction is dependent on specific receptors and respective signaling pathways in target cells. During aging, changes occur on many levels of these global systems which depend on oxidative damage, non-enzymatic glycosylation, mitochondrial mutations, defects in cell cycle control, mitotic dysregulation, genome instability, telomere shortening and other chromosomal pathologies. An alteration of the numerical value of a parameter of one system can lead to changes of the numerical value of a variable of another system. In a non-linear dynamic process these changes can contribute to the aging phenotype. Although it is extremely difficult to dissect linear interrelations of three global systems during aging, this review attempts to identify some simple linear pathways. Furthermore, it is demonstrated that chronic inflammatory diseases may accelerate the aging process. This review also reveals that new statistical and computational methods are necessary to unravel the complexity of the aging process.

Aging↗
PubMed2000

The interplay between climate change, forests, and disturbances.

Climate change affects forests both directly and indirectly through disturbances. Disturbances are a natural and integral part of forest ecosystems, and climate change can alter these natural interactions. When disturbances exceed their natural range of variation, the change in forest structure and function may be extreme. Each disturbance affects forests differently. Some disturbances have tight interactions with the species and forest communities which can be disrupted by climate change. Impacts of disturbances and thus of climate change are seen over a board spectrum of spatial and temporal scales. Future observations, research, and tool development are needed to further understand the interactions between climate change and forest disturbances.

Animals↗
PubMed1998

Neural crest development: the interplay between morphogenesis and cell differentiation.

The final pattern of tissues established during embryogenesis reflects the outcome of two developmental processes: differentiation and morphogenesis. Avian neural crest cells are an excellent system in which to study this interaction. In the first phase of neural crest cell migration, neural crest cells separate from the neural epithelium via an epithelial-mesenchymal transformation. We present three models to account for this process: (1) separation by asymmetric mitosis, (2) separation by generating tractional force in order to rupture cell adhesions and (3) loss of expression or function of cell-cell adhesion molecules that keep the presumptive neural crest cells tethered to the neural epithelium. Evidence is presented that the segregation of the neural crest lineage apart from the neural epithelium is caused by the epithelial-mesenchymal transformation. Once they have detached from the neural tube, neural crest cells take two pathways in the trunk of the chick embryo: (1) the ventral path between the neural tube and somite, where neural crest cells give rise to neurons and glial cells of the peripheral nervous systems, and (2) the dorsolateral path between the ectoderm and dermamyotome of the somite, where they differentiate into pigment cells of the skin. We present data to suggest that the migration and differentiation along the ventral path is controlled primarily by environmental cues, which we refer to as the environment-directed model of neural crest morphogenesis. Conversely, only melanoblasts can migrate into the dorsolateral space, and the ability to invade that path is dependent upon their early specification as melanoblasts. We call this the phenotype-directed model for neural crest cell migration and suggest that this latter model for the positioning of neural crest derivatives in the embryo may be more common than previously suspected. These observations invite a re-examination of patterning of other crest derivates, which previously were believed to be controlled by environmental cues.

Animals↗