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Physiological Marker (physiological + marker)
Selected AbstractsGENETIC AND PHYSIOLOGICAL VARIATION IN PIGMENT COMPOSITION OF EMILIANIA HUXLEYI (PRYMNESIOPHYCEAE) AND THE POTENTIAL USE OF ITS PIGMENT RATIOS AS A QUANTITATIVE PHYSIOLOGICAL MARKERJOURNAL OF PHYCOLOGY, Issue 3 2000Willem Stolte Genetic variation of pigment composition was studied in 16 different strains of Emiliania huxleyi (Lohm.) Hay et Mohler in batch culture. Distinct strain-dependent differences were found in the ratios of fucoxanthin, 19,-hexanoyloxyfucoxanthin, and 19,-butanoyloxyfucoxanthin, hampering the use of these individual pigments as a taxonomic marker at the species level. The molar ratio of total carotenoids to chl a, however, was constant for all strains tested. In addition, the pigment composition of one axenic strain (L) of E. huxleyi at different growth rates in light-, nitrate-, and phosphate-limited continuous cultures was analyzed quantitatively. The pigments fucoxanthin and 19,-hexanoyloxyfucoxanthin correlated closely under all conditions. From steady-state rate calculations, it is hypothesized that 19,-hexanoyloxyfucoxanthin is synthesized from fucoxanthin, with light as a modulating factor. The net rate of synthesis of diatoxanthin depended both on the concentration of diadinoxanthin (its partner in the xanthophyll cycle) and on light, illustrating its photoprotective function in the xanthophyll cycle. In axenic strain L, the ratio of total fucoxanthins to chl a correlated strongly with photon flux density and can potentially be used to assess the physiological status with respect to irradiance in field populations. In multispecific bloom situations, the ratio of diadinoxanthin plus diatoxanthin to total fucoxanthins could be used as an alternative indicator for the light-dependent physiological state of E. huxleyi, provided that no other chromophytes are present. Application of these correlations to mesocosm data from the literature has so far provided no evidence that E. huxleyi blooms form only at inhibiting light levels, as previously suggested. [source] Outcome Variables and Their Assessment in Alcohol Treatment Studies: 1968-1998ALCOHOLISM, Issue 10 2003John W. Finney Background: This article provides a historical overview of the assessment of outcome variables in alcohol treatment studies that were first published between 1968 and 1998. The review focuses on changes over time in (1) the number of outcome variables and the number of different types of outcome variables assessed, (2) the likelihood of assessing specific types of outcome variables, (3) the methods used to assess outcome variables, and (4) the status of outcome assessment in more recent studies first published between 1990 and 1998. Methods: Reports of 357 alcohol treatment trials with two or more treatment/control groups were coded with respect to the number and types of outcome variables assessed, sources of outcome data, and methodological aspects of outcome assessment. Results: Although the number of outcome variables assessed in studies, on average, did not increase significantly over time, the number of different types of outcome variables did increase. An expected decrease in the assessment of categorical abstinence was not found, but another categorical variable, global ratings of drinking improvement, did decrease over time. More recent studies were more likely to assess such continuous variables as time abstinent, alcohol consumption, time drinking, dependence symptoms, and drinking-related problems. Physiological markers of drinking/alcohol misuse also were assessed more frequently in later years. Some aspects of outcome assessment methods exhibited improvement over time; validity data were more likely to be provided or cited, and self-reports of drinking behaviors were more likely to be corroborated in studies first published in more recent years. However, the percentages of studies that provided/cited reliability data for outcome measures, indicated that follow-up data collectors were not affiliated with treatment and were unaware of respondents' treatment conditions, and reported that respondents were alcohol-free at follow-up did not rise significantly over time. Conclusions: Although the methods of outcome assessment improved between 1968 and 1998, much room for improvement remains. [source] Ankle dorsiflexion fMRI in children with cerebral palsy undergoing intensive body-weight-supported treadmill training: a pilot studyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 1 2007John P Phillips MD This pilot study investigated the feasibility of using functional magnetic resonance imaging (fMRI) as a physiological marker of brain plasticity before and after an intensive body-weight-supported treadmill training (BWSTT) program in children with cerebral palsy (CP). Six ambulatory children (four males, two females; mean age 10y 6mo, age range 6,14y) with spastic CP (four hemiplegia, two asymmetric diplegia, all Gross Motor Function Classification System Level I) received BWSTT twice daily for 2 weeks. All children tolerated therapy; only one therapy session was aborted due to fatigue. With training, over ground mean walking speed increased from 1.47 to 1.66m/s (p=0.035). There was no change in distance walked for 6 minutes (pre-: 451m; post-: 458m;p 0.851). In three children, reliable fMRIs were taken of cortical activation pre- and post-intervention. Post-intervention increases in cortical activation during ankle dorsiflexion were observed in all three children. This study demonstrates that children with CP between 6 and 14 years of age can tolerate intensive locomotor training and, with appropriate modifications, can complete an fMRI series. This study supports further studies designed to investigate training-dependent plasticity in children with CP. [source] Contaminant-associated alteration of immune function in black-footed albatross (Phoebastria nigripes), a North Pacific predatorENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2007Myra E. Finkelstein Abstract Environmental pollution is ubiquitous and can pose a significant threat to wild populations through declines in fitness and population numbers. To elucidate the impact of marine pollution on a pelagic species, we assessed whether toxic contaminants accumulated in black-footed albatross (Phoebastria nigripes), a wide-ranging North Pacific predator, are correlated with altered physiological function. Blood samples from adult black-footed albatrosses on Midway Atoll, part of the Hawaiian (USA) archipelago, were analyzed for organochlorines (e.g., polychlorinated biphenyls [PCBs] and chlorinated pesticides), trace metals (silver, cadmium, tin, lead, chromium, nickel, copper, zinc, arsenic, selenium, and total mercury), and a sensitive physiological marker, peripheral white blood cell immune function (mitogen-induced lymphocyte proliferation and macrophage phagocytosis). We found a positive significant relationship between organochlorines, which were highly correlated within individual birds (p < 0.001, r > 0.80, Spearman correlation for all comparisons; PCBs, 160 ± 60 ng/ml plasma [mean ± standard deviation]; DDTs, 140 ± 180 ng/ml plasma; chlordanes, 7.0 ± 3.6 ng/ml plasma; hexachlorobenzene, 2.4 ± 1.5 ng/ml plasma; n = 15) and increased lymphocyte proliferation (p = 0.020) as well as percentage lymphocytes (p = 0.033). Mercury was elevated in black-footed albatrosses (4,500 ± 870 ng/ml whole blood, n = 15), and high mercury levels appeared to be associated (p = 0.017) with impaired macrophage phagocytosis. The associations we documented between multiple contaminant concentrations and immune function in endangered black-footed albatrosses provide some of the first evidence that albatrosses in the North Pacific may be affected by environmental contamination. Our results raise concern regarding detrimental health effects in pelagic predators exposed to persistent marine pollutants. [source] Intrafusal effects of botulinum toxin in post-stroke upper limb spasticityEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2008C. Trompetto A previous study in subjects with focal dystonia suggested that the greater and longer-lasting effect induced by botulinum toxin type A (BoNT-A) on the tonic vibration reflex (TVR) than on the maximal M-wave (M-max) might be the physiological marker of the toxin's action at the level of intrafusal muscle fibres. With this approach, we investigated the possible effect of BoNT-A on fusimotor synapses in eight patients with post-stroke spasticity (four with no residual motor capacity before treatment and four with partially spared muscle strength and residual motor capacity). TVR and M-max were recorded from the wrist and finger flexor muscles before treatment and at 1, 4 and 7 months afterwards. The TVR reduction was greater than the M-max reduction and remained fairly constant over time only in the subjects with a residual motor capacity before the treatment. This pilot study suggests that some degree of strength and active movement is necessary for the action of BoNT-A on intrafusal fibres. [source] Socialization Ambiguity in Samoan Adolescents: A Model for Human Development and Stress in the Context of Culture ChangeJOURNAL OF RESEARCH ON ADOLESCENCE, Issue 1 2004Thomas W. McDade Rapid globalization is forcing youth around the world to confront new developmental challenges, and conceptual models are needed that can capture this experience and its developmental implications. Exposure to nontraditional lifestyles opens up new socialization opportunities and raises the possibility of stress-inducing dissonance between participating socializing agents and the messages they deliver. Socialization ambiguity is introduced as a model for culture change and adolescent stress, and it is applied to a sample of 10- to 20-year-olds (N=295) in the islands of Samoa. A physiological marker of stress (antibodies against the Epstein-Barr virus) is employed to overcome some of the difficulties associated with measuring stress outcomes. Socialization ambiguity is found to be a significant source of stress on the remote island of Savai'i and the transitional area of rural Upolu, although the direction of the association is different, possibly reflecting divergent socialization goals in these two regions. [source] Ex vivo assessment of mouse cervical remodeling through pregnancy via 23Na MRSNMR IN BIOMEDICINE, Issue 8 2010Xiang Xu Abstract Preterm birth occurs in 12.5% of births in the United States and can lead to risk of infant death or to lifelong serious health complications. A greater understanding by which the two main processes, uterine contraction and cervical remodeling are regulated is required to reduce rates of preterm birth. The cervix must undergo extensive remodeling through pregnancy in preparation for parturition, the process of labor and delivery of young. One key aspect of this dynamic process is a change in the composition and abundance of glycosaminoglycans (GAGs) and proteoglycans within the extracellular matrix, which influences the loss of tensile strength or stiffness of the cervix during labor. 23Na NMR spectroscopy has previously been validated as a method to quantify GAGs in tissues. In the current study, the Na+ concentration was measured at several time points through pregnancy in mouse cervices using 23Na NMR spectroscopy. The Na+ concentration increased progressively during pregnancy and peaked one day before birth followed by a rapid decline after birth. The same trend was seen in GAGs as measured by a biochemical assay using independent cervix samples over the course of pregnancy. We suggest that monitoring the Na+ concentration via 23Na NMR spectroscopy can serve as an informative physiological marker in evaluating the stages of cervical remodeling ex vivo and warrants further investigation to determine its utility as a diagnostic tool for the identification of women at risk for impending preterm birth. Copyright © 2010 John Wiley & Sons, Ltd. [source] Prenatal predictors of infant temperamentDEVELOPMENTAL PSYCHOBIOLOGY, Issue 5 2007Elizabeth A. Werner Abstract Emerging data suggest that prenatal factors influence children's temperament. In 50 dyads, we examined fetal heart rate (FHR) activity and women's antenatal psychiatric illness as predictors of infant temperament at 4 months (response to novelty and the Infant Behavior Checklist). FHR change during maternal challenge was positively associated with observed infant motor reactivity to novelty (p,=,.02). The odds of being classified as high versus low motor among fetuses who had an increase in FHR during maternal stress was 11 times those who had a decrease in FHR (p,=,.0006). Antenatal psychiatric diagnosis was associated with an almost fourfold greater odds of having a high cry reactivity classification (p,=,.03). There also were modest associations between baseline FHR and maternal reports of infant temperament and between observed temperament and that based on mothers' reports. All of the infant results were found independent of the influence of women's postnatal anxiety. These data indicate that physiological markers of individual differences in infant temperament are identifiable in the fetal period, and possibly shaped by the prenatal environment. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 474-484, 2007. [source] Programmed cell death (PCD) processes begin extremely early in Alstroemeria petal senescenceNEW PHYTOLOGIST, Issue 1 2003Carol Wagstaff Summary ,,In the Liliaceous species Alstroemeria, petal senescence is characterized by wilting and inrolling, terminating in abscission 8,10 d after flower opening. ,,In many species, flower development and senescence involves programmed cell death (PCD). PCD in Alstroemeria petals was investigated by light (LM) and transmission electron microscopy (TEM) (to study nuclear degradation and cellular integrity), DNA laddering and the expression programme of the DAD-1 gene. ,,TEM showed nuclear and cellular degradation commenced before the flowers were fully open and that epidermal cells remained intact whilst the mesophyll cells degenerated completely. DNA laddering increased throughout petal development. Expression of the ALSDAD-1 partial cDNA was shown to be downregulated after flower opening. ,,We conclude that some PCD processes are started extremely early and proceed throughout flower opening and senescence, whereas others occur more rapidly between stages 4,6 (i.e. postanthesis). The spatial distribution of PCD across the petals is discussed. Several molecular and physiological markers of PCD are present during Alstroemeria petal senescence. [source] Influence of successive bouts of fatiguing exercise on perceptual and physiological markers during an incremental exercise testPSYCHOPHYSIOLOGY, Issue 1 2009Jeremy B.J. Coquart Abstract The purpose of this study was to examine the effects of a succession of fatiguing stages, on ratings of perceived exertion (RPE) and estimated time limits (ETL) during an incremental exercise test. Twenty-seven cyclists performed a continuous incremental test and a discontinuous test with randomized workloads. A linear mixed model was used to compare the RPE, ETL, respiratory gas, heart rate, and blood data obtained during the two exercise tests. RPE and ETL were not significantly different between the tests. Ventilation, breathing frequency, heart rate, and blood lactate concentration were significantly higher during the last incremental test workloads. In conclusion, although the incremental exercise test generated higher cardiorespiratory and muscular workloads than observed during the randomized exercise test, most likely due to a greater fatiguing process, these higher workloads did not influence the perceptual response. [source] Role of the Neurokinin-1 Receptors in Ejaculation in Anesthetized RatsTHE JOURNAL OF SEXUAL MEDICINE, Issue 1 2009Pierre Clement PhD ABSTRACT Introduction., Several lines of evidence indicate a role for substance P in the control of ejaculation, although its mode of action needs to be clarified. Aim., The effects and sites of action of a selective antagonist for the substance P-preferred receptor (neurokinin-1 receptor subtype; NK1) were investigated in a pharmacological model of ejaculation. Methods., Ejaculation was induced in anesthetized rats by intracerebroventricular (icv) delivery of the dopamine D3 receptor preferring agonist 7-hydroxy-2-(di-N-propylamino)tetralin (7-OH-DPAT). The effects of the selective NK1 antagonist RP67580 on 7-OH-DPAT-induced ejaculation were measured following intraperitoneal (ip), icv, or intrathecal (it) (third lumbar spinal segment; L3) administration. Main Outcome Measures., Intraseminal vesicle pressure (SVP) and electromyogram of the bulbospongiosus muscle (BS) were recorded as physiological markers of emission and expulsion phases of ejaculation, respectively. Results., Upon ip, icv, or it administration, RP67580 significantly reduced the occurrence of ejaculation elicited by 7-OH-DPAT. A mild decrease in the occurrence of SVP and BS responses was observed in rats treated ip with RP67580, whereas only SVP responses were moderately affected following icv or it administration. Conclusion., These results show the multilevel regulation of 7-OH-DPAT-induced ejaculation by NK1 receptors. Clement P, Peeters M, Bernabe J, Laurin M, Alexandre L, and Giuliano F. Role of the neurokinin-1 receptors in ejaculation in anesthetized rats. J Sex Med 2009;6:126,134. [source] | ||||||||||||||||