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Physiological Consequences (physiological + consequence)
Selected AbstractsPhysiological effects of dominance hierarchies: laboratory artefacts or natural phenomena?JOURNAL OF FISH BIOLOGY, Issue 1 2002K. A. Sloman Studies of fish behaviour have demonstrated the existence of social interactions that result in dominance hierarchies. In environments in which resources, such as food, shelter and mates, are limited, social competition results in some fish becoming dominant and occupying the most profitable positions. This behaviour has been observed in natural environments and also in many laboratory-based experiments. When two fish have been confined in a small tank, one of them usually has exhibited behaviour that suggests it is dominant over the other submissive animal. Physiological consequences of social interaction can be seen in both dominants and subordinates but are more extreme in the subordinate. However, this scenario is without doubt an artificial situation. Fewer experiments have been conducted using laboratory experiments that are more socially and physically complex than those experienced by dyads in tanks. In simple fluvial tanks, through which water is recirculated, the physiological responses of fish to social competition have generally been qualitatively similar to those recorded among dyads. However, when environmental disturbances, complex resource distributions, increase in water flushing, presence of predators and competing species of fish have been included in experimen-tal designs, there have been fewer, diminished or no physiological dierences between dominant and subordinate fish. There have been very few studies of physiology in relation to dominance in natural habitats, and those that have been conducted suggest that under some circumstances hierarchies may cause less intense physiological responses than have been suggested based on results of laboratory studies in simple environments. Possible reasons for these variations are discussed. The need is identified for a well structured experimental approach to the investi-gation of the causes and consequences of hierarchies if the ecology of wild fish is to be modelled eectively based on physiological processes. It is also suggested that the further development and application of techniques for monitoring physiologies of fish in the wild is important. [source] The physiological role of hormones in salivaBIOESSAYS, Issue 8 2009Michael Gröschl Abstract The assessment of hormones in saliva has gained wide acceptance in clinical endocrinology. To date, there is no hypothesis as to why some hormones can be found in saliva, while others cannot, and whether there is a physiological consequence of this fact. A number of carefully performed studies give examples of important physiological hormonal activity in saliva. Steroids, such as androgens, act as pheromones in olfactory communication of various mammalian species, such as facilitating mating behavior in swine or serving as odor cues for rodent nestlings. Salivary peptide hormones, such as epidermal growth factor (EGF) and transforming growth factor-, (TGF-,), and amines such as melatonin, are involved in the regulation of inflammatory processes and in the promotion of cell proliferation, and contribute to a rapid wound healing in the oropharyngeal epithelia. Current data provide evidence of the involvement of salivary cytokines, such as interleukin-8 and leptin, in tumorgenesis in the oral cavity and the salivary glands. The tumor tissues express and release significantly more of these cytokines than healthy glands. Consequently, the assessment of salivary hormone profiles may provide promising targets for diagnostic tumor markers. [source] Physiological and Behavioral Differences in Magellanic Penguin Chicks in Undisturbed and Tourist-Visited Locations of a ColonyCONSERVATION BIOLOGY, Issue 5 2005BRIAN G. WALKER corticoesterona; ecoturismo; perturbación humana; Spheniscus magellanicus Abstract:,Studies examining anthropogenic effects on wildlife typically focus on adults and on behavioral responses rather than the physiological consequences of human disturbances. Here we examined how Magellanic Penguin ( Spheniscus magellanicus) chicks living in either tourist-visited or undisturbed areas of a breeding colony were affected by human visitation by comparing the baseline and stress-induced levels of corticosterone during three periods of the breeding season. Newly hatched chicks in visited areas had higher corticosterone stress responses than newly hatched chicks in undisturbed areas (p =0.007), but baseline levels were similar (p =0.61). By 40,50 days of age and around fledging time, both visited and undisturbed chicks showed a robust corticosterone stress response to capture. Tourist-visited chicks did not flee when approached by humans, however, whereas undisturbed chicks fled significantly sooner (i.e., when approached no closer than 9 m; p < 0.0001). Although it is unknown whether Magellanic Penguin chicks raised in visited areas suffer negative consequences from the elevation of the corticosterone stress response at hatching, they do exhibit behavioral habituation to human contact by the time they are ready to fledge. Unlike adults living in tourist areas, however, fledging chicks in visited areas do not have a decreased stress response to capture and restraint. Our results show that the coupling of behavioral and physiological habituation in Magellanic Penguins is complex and life-history context may greatly affect the ability of wildlife to adapt to anthropogenic disturbances. Resumen:,Los estudios de los efectos antropogénicos sobre la vida silvestre se centran típicamente en adultos y en las respuestas conductuales en lugar de las consecuencias fisiológicas de las perturbaciones humanas. Aquí examinamos el efecto de la visita de humanos sobre pollos de pingüino (Spheniscus magellanicus) en áreas visitadas por turistas o no perturbadas mediante la comparación de los niveles, base e inducidos por estrés, de corticoesterona durante tres períodos de la temporada reproductiva. Los pollos recién eclosionados en áreas visitadas tuvieron mayor respuesta de la corticoesterona al estrés que los pollos recién eclosionados en áreas no perturbadas (p =0.007), pero los niveles básicos fueron similares (p =0.61). A los 40,50 días y en la etapa de volantón, los pollos visitados y no perturbados mostraron una marcada respuesta de la corticoesterona al estrés al ser capturados. Sin embargo, los pollos visitados por turistas no huyeron cuando se les acercaron humanos, mientras que los pollos no perturbados huyeron significativamente antes (i.e., acercamiento a más de 9 m; p < 0.0001). Aunque se desconoce si los pollos de pingüino criados en áreas visitadas sufren consecuencias negativas por la elevación de la corticosterona en respuesta al estrés al eclosionar, si presentan acostumbramiento conductual al contacto con humanos al momento que están listos para dejar el nido. Sin embargo, a diferencia de adultos que viven en áreas turísticas, los pollos volantones en las áreas visitadas no tienen una disminución en la respuesta al estrés cuando son capturados y sujetados. Nuestros resultados muestran la complejidad de la combinación del acostumbramiento conductual y fisiológico en Spheniscus magellanicus y que el contexto de la historia de vida puede afectar a la habilidad de la vida silvestre para adaptarse a las perturbaciones antropogénicas. [source] Scaffolding proteins organize multimolecular protein complexes for sensory signal transductionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2001Armin Huber Abstract Scaffolding proteins composed of protein,protein interaction domains have emerged as organizers of multiprotein complexes in diverse cellular compartments, including neuronal synapses, cell,cell junctions of epithelial cells, and the stimulus perceiving structures of sensory neurons. This review focuses on the INAD-assembled signalling complex of Drosophila photoreceptors, which organizes key components of the phototransduction cascade into a multiprotein signal transduction unit. The structure, the physiological consequences, and the assembly and targeting of the members of the INAD signalling complex will be described. In addition, the existence of signalling complexes in vertebrate photoreceptors, olfactory neurons and mechanosensitive hair cells will be discussed. [source] To breathe or not to breathe?EXPERIMENTAL PHYSIOLOGY, Issue 1 2009That is the question Our understanding of the role of the brain in respiratory rhythm generation and regulation began the early nineteenth century. Over the next 150 years the neuronal groups in the medulla oblongata and pons that were involved in eupnoea and in gasping were identified by techniques involving the lesioning of areas of the lower brainstem, several transections across the brainstem and focal electrical stimulation. An incomplete picture emerged that stressed the importance of the ventral medulla. Subsequent electrophysiological studies in in vivo, in situ and in vitro preparations have revealed the importance of restricted groups of neurones in this area, within the Bötzinger and pre-Bötzinger nuclei, that are the essential kernel for rhythm generation. The outputs to the spinal motoneurones responsible for the patterning of inspiratory and expiratory discharge are shaped by inputs from these neurones and others within the respiratory complex that determine the activity of respiratory bulbospinal neurones. It is clear that the developmental stage of the preparation is often critical for the pattern of respiratory activity that is generated and that these patterns have important physiological consequences. The models that are currently considered to explain rhythmogenesis are critically evaluated. The respiratory network is subject to regulation from peripheral and central chemoreceptors, amongst other afferent inputs, which act to ensure respiratory homeostasis. The roles of peripheral chemoreceptors as primarily O2 sensors are considered, and the evolution of ideas surrounding their roles is described. New insights into the transduction mechanisms of chemoreception in the carotid body and chemosensitive areas of the ventral medullary surface, specifically in monitoring CO2 levels, are reviewed. As new experimental tools, both genetic and cellular, are emerging, it can be expected that the detailed network architecture and synaptic interactions that pattern respiratory activity in relation to behavioural activity will be revealed over the next years. [source] Mitochondrial DNA mutations as a fundamental mechanism in physiological declines associated with agingAGING CELL, Issue 1 2003Jeong W. Pak Summary The hypothesis that mitochondrial DNA damage accumulates and contributes to aging was proposed decades ago. Only recently have technological advancements, which facilitate microanalysis of single cells or portions of cells, revealed that mtDNA deletion mutations and, perhaps, single nucleotide mutations accumulate to physiologically relevant levels in the tissues of various species with age. Although a link between single nucleotide mutations and physiological consequences in aging tissue has not been established, the accumulation of deletion mutations in skeletal muscle fibres has been associated with sarcopenia. Different, and apparently random, deletion mutations are specific to individual fibres. However, the mtDNA deletion mutation within a phenotypically abnormal region of a fibre is the same, suggesting a selection, amplification and clonal expansion of the initial deletion mutation. mtDNA deletion mutations within a muscle fibre are associated with specific electron transport system abnormalities, muscle fibre atrophy and fibre breakage. These data point to a causal relationship between mitochondrial DNA mutations and the age-related loss of muscle mass. [source] Muscarinic receptors: do they have a role in the pathology and treatment of schizophrenia?JOURNAL OF NEUROCHEMISTRY, Issue 5 2008Elizabeth Scarr Abstract The high affinity of antipsychotic drugs for the dopamine D2 receptor focused attention onto the role of these receptors in the genesis of psychoses and the pathology of schizophrenia. However, psychotic symptoms are only one aspect of the complex symptom profile associated with schizophrenia. Therefore, research continues into other neurochemical systems and their potential roles in key features associated with schizophrenia. Modulating the cholinergic system in attempts to treat schizophrenia predates specific neurochemical hypotheses of the disorder. Cholinergic modulation has progressed from the use of coma therapy, through the use of anti-cholinergic drugs to control side-effects of older (typical) antipsychotic medications, to the development of drugs designed to specifically activate selected muscarinic receptors. This review presents data implicating a decrease in muscarinic receptors, particularly the M1 receptor, in the pathology of schizophrenia and explores the potential physiological consequences of such a change, drawing on data available from muscarinic receptor knockout mice as well as clinical and pre-clinical pharmacology. The body of evidence presented suggests that deficits in muscarinic receptors are associated with some forms of schizophrenia and that targeting these receptors could prove to be of therapeutic benefit to patients with the disorder. [source] UV-A/BLUE LIGHT,INDUCED REACTIVATION OF SPORE GERMINATION IN UV-B IRRADIATED ULVA PERTUSA (CHLOROPHYTA),JOURNAL OF PHYCOLOGY, Issue 2 2004Taejun Han Recent reduction in the ozone shield due to manufactured chlorofluorocarbons raised considerable interest in the ecological and physiological consequences of UV-B radiation (,=280,315 nm) in macroalgae. However, early life stages of macroalgae have received little attention in regard to their UV-B sensitivity and UV-B defensive mechanisms. Germination of UV-B irradiated spores of the intertidal green alga Ulva pertusa Kjellman was significantly lower than in unexposed controls, and the degree of reduction correlated with the UV doses. After exposure to moderate levels of UV-B irradiation, subsequent exposure to visible light caused differential germination in an irradiance- and wavelength-dependent manner. Significantly higher germination was found at higher photon irradiances and in blue light compared with white and red light. The action spectrum for photoreactivation of germination in UV-B irradiated U. pertusa spores shows a major peak at 435 nm with a smaller but significant peak at 385 nm. When exposed to December sunlight, the germination percentage of U. pertusa spores exposed to 1 h of solar radiation reached 100% regardless of the irradiation treatment conditions. After a 2-h exposure to sunlight, however, there was complete inhibition of germination in PAR+UV-A+UV-B in contrast to 100% germination in PAR or PAR+UV-A. In addition to mat-forming characteristics that would act as a selective UV-B filter for settled spores under the parental canopy, light-driven repair of germination after UV-B exposure could explain successful continuation of U. pertusa spore germination in intertidal settings possibly affected by intense solar UV-B radiation. [source] Analysis of gastrointestinal physiology using a novel intestinal transit assay in zebrafishNEUROGASTROENTEROLOGY & MOTILITY, Issue 3 2009H. A. Field Abstract, Gastrointestinal function depends upon coordinated contractions to mix and propel food through the gut. Deregulation of these contractions leads to alterations in the speed of material transit through the gut, with potentially significant consequences. We have developed a method for visualizing intestinal transit, the physiological result of peristaltic contractions, in larval zebrafish. This method allows direct, non-invasive observation of luminal content as it traverses the gut. Using this method, we characterized gastrointestinal transit in zebrafish larvae at 7 days postfertilization. In addition, we used this transit assay to assess the physiological consequences of reduced or absent enteric neurones on intestinal transit in larval zebrafish. This may facilitate the use of the zebrafish for investigating the effect of compounds and candidate genes on gastrointestinal motility. [source] Low-fat diets, triglycerides and coronary heart disease riskNUTRITION BULLETIN, Issue 1 2000Helen M. Roche Summary Nutritionists are currently debating whether low-fat high-carbohydrate diets protect against coronary heart disease (CHD). Traditionally, low-fat diets were prescribed because they reduce plasma and low density lipoprotein (LDL) cholesterol concentrations. However, there is considerable concern because low-fat diets also increase plasma triglyceride (TG) and reduce high density lipoprotein (HDL) cholesterol concentrations. Recent prospective epidemiological studies have shown that these are independent risk factors for future CHD risk. It has been proposed that the adverse effects of low-fat, high-carbohydrate diets on TG and HDL may counteract or negate the beneficial effect of reducing LDL cholesterol concentrations. Although there is also strong epidemiological evidence that reduced total fat intake is not protective against CHD, high-fat diets predispose to obesity and insulin resistance, both of which adversely affect TG metabolism. This review presents the evidence in relation to the importance of TG as a risk factor for CHD, and explains the pathophysiology that may underlie the aetiological role of TG metabolism in the pathogenesis and progression of CHD. It also addresses the physiological consequences of advocating low-fat high-carbohydrate diets, with particular reference to the effects on lipoprotein metabolism and CHD risk. [source] Validity, reliability, and applicability of psychophysiological techniques in marketing researchPSYCHOLOGY & MARKETING, Issue 2 2008Yong Jian Wang A variety of psychophysiological techniques have been used in the measurement of consumer reactions to marketing stimuli since the 60s. The objectives of this paper are: (1) to present a descriptive review of the psychophysiological techniques and (2) to discuss critical concerns about validity, reliability, and applicability of these psychophysiological techniques raised by previous research. The strengths and weaknesses of ten major psychophysiological techniques are analyzed on the basis of the summaries of 67 marketing studies that have employed psychophysiological techniques. This study shows a need for marketing research to establish validity and reliability and to emphasize applicability when psychophysiological techniques are to be used. Meeting such a need requires an understanding of the nuanced psychophysiological process that links particular psychological antecedents and the physiological consequences being measured. A framework for analyzing this psychophysiological process in marketing research is provided. © 2008 Wiley Periodicals, Inc. [source] Comparative study of brain morphology in Mecp2 mutant mouse models of Rett syndromeTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2008Nadia P. Belichenko Abstract Rett syndrome (RTT) is caused by mutations in the X-linked gene MECP2. While patients with RTT show widespread changes in brain function, relatively few studies document changes in brain structure and none examine in detail whether mutations causing more severe clinical phenotypes are linked to more marked changes in brain structure. To study the influence of MeCP2-deficiency on the morphology of brain areas and axonal bundles, we carried out an extensive morphometric study of two Mecp2-mutant mouse models (Mecp2B and Mecp2J) of RTT. Compared to wildtype littermates, striking changes included reduced brain weight (,13% and ,9%) and the volumes of cortex (,11% and ,7%), hippocampus (both by ,8%), and cerebellum (,12% and 8%) in both mutant mice. At 3 weeks of age, most (24 of 47) morphological parameters were significantly altered in Mecp2B mice; fewer (18) were abnormal in Mecp2J mice. In Mecp2B mice, significantly lower values for cortical area were distributed along the rostrocaudal axis, and there was a reduced length of the olfactory bulb (,10%) and periaqueductal gray matter (,16%). In Mecp2J mice, while there was significant reduction in rostrocaudal length of cortex, this parameter was also abnormal in hippocampus (,10%), periaqueductal gray matter (,13%), fimbria (,18%), and anterior commissure (,10%). Our findings define patterns of Mecp2 mutation-induced changes in brain structure that are widespread and show that while some changes are present in both mutants, others are not. These observations provide the underpinning for studies to further define microarchitectural and physiological consequences of MECP2 deficiency. J. Comp. Neurol. 508:184,195, 2008. © 2008 Wiley-Liss, Inc. [source] Empirical and theoretical dosimetry in support of whole body radio frequency (RF) exposure in seated human volunteers at 220 MHz,BIOELECTROMAGNETICS, Issue 6 2005Stewart J. Allen Abstract This study reports the dosimetry performed to support an experiment that measured physiological responses of seated volunteer human subjects exposed to 220 MHz fields. Exposures were performed in an anechoic chamber which was designed to provide uniform fields for frequencies of 100 MHz or greater. A vertical half-wave dipole with a 90° reflector was used to optimize the field at the subject's location. The vertically polarized E field was incident on the dorsal side of the phantoms and human volunteers. The dosimetry plan required measurement of stationary probe drift, field strengths as a function of distance, electric and magnetic field maps at 200, 225, and 250 cm from the dipole antenna, and specific absorption rate (SAR) measurements using a human phantom, as well as theoretical predictions of SAR with the finite difference time domain (FDTD) method. A NBS (National Bureau of Standards, now NIST, National Institute of Standards and Technology, Boulder, CO) 10 cm loop antenna was positioned 150 cm to the right, 100 cm above and 60 cm behind the subject (toward the transmitting antenna) and was read prior to each subject's exposure and at 5 min intervals during all RF exposures. Transmitter stability was determined by measuring plate voltage, plate current, screen voltage and grid voltage for the driver and final amplifiers before and at 5 min intervals throughout the RF exposures. These dosimetry measurements assured accurate and consistent exposures. FDTD calculations were used to determine SAR distribution in a seated human subject. This study reports the necessary dosimetry to precisely control exposure levels for studies of the physiological consequences of human volunteer exposures to 220 MHz. Bioelectromagnetics 26:440,447, 2005. Published 2005 Wiley-Liss, Inc. [source] Conjugated linoleic acid isomers: Differences in metabolism and biological effectsBIOFACTORS, Issue 1 2009Itziar Churruca Abstract The term conjugated linoleic acid (CLA) refers to a mixture of linoleic acid positional and geometric isomers, characterized by having conjugated double bonds, not separated by a methylene group as in linoleic acid. CLA isomers appear as a minor component of the lipid fraction, found mainly in meat and dairy products from cows and sheep. The most abundant isomer is cis -9,trans -11, which represents up to 80% of total CLA in food. These isomers are metabolized in the body through different metabolic pathways, but important differences, that can have physiological consequences, are observed between the two main isomers. The trans -10,cis -12 isomer is more efficiently oxidized than the cis -9,trans -11 isomer, due to the position of its double bounds. Interest in CLA arose in its anticarcinogenic action but there is an increasing amount of specific scientific literature concerning the biological effects and properties of CLA. Numerous biological effects of CLA are due to the separate action of the most studied isomers, cis -9,trans -11 and trans -10,cis -12. It is also likely that some effects are induced and/or enhanced by these isomers acting synergistically. Although the cis -9,trans -11 isomer is mainly responsible for the anticarcinogenic effect, the trans -10,cis -12 isomer reduces body fat and it is referred as the most effective isomer affecting blood lipids. As far as insulin function is concerned, both isomers seem to be responsible for insulin resistance in humans. Finally, with regard to the immune system it is not clear whether individual isomers of CLA could act similarly or differently. © 2009 International Union of Biochemistry and Molecular Biology, Inc. [source] Causal link between neonatal hydronephrosis and later development of hypertensionCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 2 2010Mattias Carlström Summary 1. Although congenital ureteral obstruction is a common disorder in infants, its pathophysiology remains poorly understood and its clinical management continues to be debated. During the past decade, the surgical management of non-symptomatic hydronephrosis in children has become more conservative, but the long-term physiological consequences of this new policy are unclear. 2. In experimental models with complete ureteral obstruction, tubular atrophy and interstitial inflammation occur rapidly. Although this type of obstruction is very rare in clinical practice, it is often referred to in clinical discussions. New studies, using a model with chronic partial ureteral obstruction, have demonstrated that hydronephrosis is associated with renal injuries and is causally related to hypertension. 3. The mechanisms underlying the development of hypertension in experimental hydronephrosis are complex and involve changes in both the renin,angiotensin system and renal sympathetic nerve activity. Furthermore, oxidative stress and nitric oxide deficiency in the diseased kidney, with consequent resetting of the tubuloglomerular feedback mechanism, appear to play a pivotal role in the development and maintenance of hyper-tension. 4. In view of the new knowledge regarding the long-term effects of partial ureteral obstruction, today's non-operative management of hydronephrosis should be reconsidered to prevent obstructive nephropathy and hypertension in later life. [source] | |||||||||||||