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Physiological Approaches (physiological + approach)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

Signal Transduction Pathways in Enhanced Microvascular Permeability

MICROCIRCULATION, Issue 6 2000
SARAH Y. YUAN
ABSTRACT We have been investigating the molecular mechanisms underlying pathophysiological regulation of microvascular permeability on isolated venules and cultured venular endothelial monolayers. Physiological approaches have been employed in combination with molecular analyses to probe the signal transduction pathways leading to enhanced microvascular permeability. A newly developed technique of protein transfection into cells and intact microvessels enables the correlation of functional reactions and signaling events at the molecular level in a direct and specific fashion. The results indicate that inflammatory mediators increase microvascular permeability via intracellular signaling pathways involving the activation of phospholipase C, cytosolic calcium, protein kinase C, nitric oxide synthase, guanylate cyclase, and protein kinase G. In response to the signaling stimulation, complex biochemical and conformational reactions occur at the endothelial structural proteins. Specifically, myosin light-chain activation-mediated myosin light-chain phosphorylation can result in cell contraction. VE-cadherin and ,-catenin phosphorylation may induce dissociation of the junctional proteins and their connection to the cytoskeleton, leading to a loose or opened intercellular junction. Focal adhesion phosphorylation and redistribution further provide an anchorage support for the conformational changes in the cells and at the cell junction. The three processes may act in concert to facilitate the flux of fluid and macromolecules across the microvascular endothelium. [source]

Psychodynamic and Neurological Perspectives on ADHD: Exploring Strategies for Defining a Phenomenon

JOURNAL FOR THE THEORY OF SOCIAL BEHAVIOUR, Issue 4 2001
Adam Rafalovich
This article is a discourse analysis of two historical inquiries into what clinici-ans today call attention deficit hyperactivity disorder (ADHD). Of primary con-cern in this regard are psychodynamic perspectives towards ADHD symptoms, championed by psychoanalysts and psychologists, and neurological perspectives towards ADHD, which continue to favor a purely physiological approach to understanding the disorder. Those within the psychodynamic camp are inclined to view ADHD as an interactional difficulty between self and social environment - a condition best remedied by psychotherapy. Those within the neurological camp see ADHD as a specific brain process, whose effective treatment depends upon adequate psychopharmacology. This essay argues that both psychodynamic and neurological perspectives towards ADHD have strategized to legitimate one perspective through the expulsion of the other. Within the current era of ADHD nomenclature and treatment it is clear that neurological perspectives dominate the debate. However, neurological perspectives continue to be haunted by a considerable amount of skepticism, both nationally and internationally. Because of this it would be difficult to assert that neurological perspectives, though winning the "legitimation race" in contemporary understandings of ADHD, are entirely monolithic sources of ADHD knowledge. [source]

In vitro and in vivo studies on the generation of the primary T-cell receptor repertoire

IMMUNOLOGICAL REVIEWS, Issue 1 2004
Ferenc Livák
Summary:, The primary T-cell receptor repertoire is generated by somatic rearrangement of discontinuous gene segments. The shape of the combinatorial repertoire is stereotypical and, in part, evolutionarily conserved among mammals. Rearrangement is initiated by specific interactions between the recombinase and the recombination signals (RSs) that flank the gene segments. Conserved sequence variations in the RS, which modulate its interactions with the recombinase, appear to be a major factor in shaping the primary repertoire. In vitro, biochemical studies have revealed distinct steps in these complex recombinase,RS interactions that may determine the final frequency of gene segment rearrangement. These studies offer a plausible model to explain gene segment selection, but new, more physiological approaches will have to be developed to verify and refine the mechanism by which the recombinase targets the RS in its endogenous chromosomal context in vivo. [source]

Multimodal techniques for smoking cessation: a review of their efficacy and utilisation and clinical practice guidelines

INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 11 2008
V. I. Reus
Summary Aims:, Nicotine addiction is a complex, chronic condition with physiological and psychological/behavioural aspects that make smoking cessation extremely difficult. This paper reviews current recommendations for smoking cessation and the efficacy of pharmacotherapy and behavioural modification techniques, used either alone or in combination, for smoking cessation. Results:, Abstinence rates for pharmacotherapies range from ,16% to ,30% at 1-year follow-up, with efficacy odds ratios (ORs) compared with placebo of ,1.7 for nicotine replacement therapy (NRT), ,1.9 for bupropion sustained release and ,3.0 for varenicline. Behaviour modification therapies have achieved quit rates of between 8% and 43% for up to 1 year, with ORs in comparison to no treatment of between ,1.2 and ,2.2. No direct comparisons have been made between pharmacotherapy alone and psychological behaviour strategies alone. However, combining physiological approaches with counselling significantly increases the odds of quitting compared with either technique alone. Conclusions:, Applying multimodal techniques for the treatment of nicotine addiction is the recommended approach and has demonstrated the potential to improve rates of permanent abstinence in smokers attempting cessation. While the numbers of patients receiving help and advice regarding smoking cessation is increasing, the multimodal approach appears to be currently underutilised by clinicians and therefore smoking cessation strategies are not being optimised. [source]

Nitric oxide in plants: the history is just beginning

PLANT CELL & ENVIRONMENT, Issue 3 2001
M. V. Beligni
ABSTRACT Nitric oxide (NO) is a bioactive molecule that exerts a number of diverse activities in phylogenetically distant species, as well as opposing effects in related biological systems. It was firstly described in mammals as a major messenger in the cardiovascular, immune and nervous system, in which it plays regulatory, signalling, cytoprotective and cytotoxic effects (Ignarro, Annual Review of Pharmacology and Toxicology 30, 535,560, 1990; Anbar, Experientia 51, 545,550, 1995). This versatility is mainly achieved through interactions with targets via either a redox or an additive chemistry (Stamler, Cell 78, 931,936, 1994). For this reason, metal- and thiol-containing proteins serve as major target sites for NO: these include signalling proteins, receptors, enzymes, transcription factors and DNA, among others. Furthermore, NO is a small, highly diffusible molecule. It rapidly crosses biological membranes and triggers various different processes in a short period of time. In this context, NO can co-ordinate and regulate cellular functions of microsomes and organelles such as mitochondria. The ubiquity of NO reactions, as well as the finding that the biochemical and molecular mechanisms underlying many physiological processes are well conserved between diverse species, have opened the exploration of NO chemistry in different organisms. Among these, plants were not the exception. The research in plants has been focused on three main fields: (i) the search for NO or any source of NO generation; (ii) the examination of the effects of NO upon exogenous treatments; and (iii) the search for the same molecules involved in NO-sensitive transduction pathways as in animals (e.g. cGMP, Ca2+, calmodulin). As it is evident from this review, recent progress on NO functionality in plants has been impressive. With the use of biochemistry, molecular genetics and structural biology, together with classical physiological approaches, an explosion of new discoveries will surely begin. It is certainly a good time for plant biologists. [source]