Home About us Contact
|
Home About us Contact | ||
|
|
||
Physiological Data (physiological + data)
Selected AbstractsImmunocytochemical mapping and quantification of expression of a putative type 1 serotonin receptor in the crayfish nervous systemTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2005Nadja Spitzer Abstract Serotonin is an important neurotransmitter that is involved in modulation of sensory, motor, and higher functions in many species. In the crayfish, which has been developed as a model for nervous system function for over a century, serotonin modulates several identified circuits. Although the cellular and circuit effects of serotonin have been extensively studied, little is known about the receptors that mediate these signals. Physiological data indicate that identified crustacean cells and circuits are modulated via several different serotonin receptors. We describe the detailed immunocytochemical localization of the crustacean type 1 serotonin receptor, 5-HT1crust, throughout the crayfish nerve cord and on abdominal superficial flexor muscles. 5-HT1crust is widely distributed in somata, including those of several identified neurons, and neuropil, suggesting both synaptic and neurohormonal roles. Individual animals show very different levels of 5-HT1crust immunoreactivity (5-HT1crustir) ranging from preparations with hundreds of labeled cells per ganglion to some containing only a handful of 5-HT1crustir cells in the entire nerve cord. The interanimal variability in 5-HT1crustir is great, but individual nerve cords show a consistent level of labeling between ganglia. Quantitative RT-PCR shows that 5-HT1crust mRNA levels between animals are also variable but do not directly correlate with 5-HT1crustir levels. Although there is no correlation of 5-HT1crust expression with gender, social status, molting or feeding, dominant animals show significantly greater variability than subordinates. Functional analysis of 5-HT1crust in combination with this immunocytochemical map will aid further understanding of this receptor's role in the actions of serotonin on identified circuits and cells. J. Comp. Neurol. 484:261,282, 2005. © 2005 Wiley-Liss, Inc. [source] Effects of pre- and postnatal polychlorinated biphenyl exposure on metabolic rate and thyroid hormones of white-footed mice,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2001John B. French Jr. Abstract Energy budgets have proven to be a valuable tool for predicting life history from physiological data in terrestrial vertebrates, yet these concepts have not been applied to the physiological effects of contaminants. Contaminants might affect energy budgets by imposing an additional metabolic cost or by reducing the overall amount of energy taken in; either process will reduce the energy available for production (i.e., growth or reproduction). This study examined whole animal energetic effects of polychlorinated biphenyl (PCB) exposure in white-footed mice (Peromyscus leucopus). Exposure to PCBs is known to reduce concentrations of plasma thyroid hormones, and thyroid hormones exert strong control over the rate of energy metabolism in mammals. Peromyscus leucopus that were proven breeders were fed PCBs in their food at 0, 10, and 25 ppm. Through lactation, offspring were exposed to PCB from conception and were maintained on the maternal diet to adulthood. No effects were seen on energy metabolism (O2 consumption, measured in adulthood) or on growth, but there were large dose-dependent decreases in thyroid hormone concentrations, particularly T4. The apparent disparity in our data between unchanged metabolic rates and 50% reductions in T4 concentrations can be rationalized by noting that free T3 (the fraction not bound to plasma protein) in treated mice was not significantly different from controls and that metabolism is most strongly influenced by free T3. Overall, this study did not demonstrate any energetic consequences of PCB exposure in P. leucopus at dietary concentrations up to 25 ppm. [source] Evaluating low level sequence identitiesFEBS JOURNAL, Issue 2 2001AROM homologous?, Are Aspergillus QUTA A review published several years ago [Hawkins, A.R. & Lamb, H.K. (1995) Eur. J. Biochem. 232, 7,18] proposed that genetic, biochemical and physiological data can override sequence comparison in the determination of homology in instances where structural information is unavailable. Their lead example was the hypothesis that the transcriptional activator protein for quinate catabolism in Aspergillus nidulans, QUTA, is derived from the pentafunctional AROM protein by a gene duplication followed by cleavage [Hawkins, A.R., Lamb, H.K., Moore, J.D. & Roberts, C.F. (1993) Gene136, 49,54]. We tested this hypothesis by a sensitive combination of position-specific log-odds scoring matrix methods. The position-specific log-odds scoring matrices were derived from a large number of 3-dehydroquinate synthase and 5- enolpyruvylshikimate-3-phosphate synthase domains that were proposed to be the domains from the AROM protein that gave rise to the transcriptional activator protein for quinate metabolism. We show that the degree and pattern of similarity between these position-specific log-odds scoring matrices and the transcriptional activator protein for quinate catabolism in A. nidulans is that expected for random sequences of the same composition. This level of similarity provides no support for the suggested gene duplication and cleavage. The lack of any trace of evidence for homology following a comprehensive sequence analysis indicates that the homology hypothesis is without foundation, underlining the necessity to accept only similarity of sequence and/or structure as evidence of evolutionary relatedness. Further, QUTA is homologous throughout its entire length to an extended family of fungal transcriptional regulatory proteins, rendering the hypothesized QUTA,AROM homology even more problematic. [source] Objective emotional assessment of tactile hair properties and their modulation by different product worldsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2002W. Boucsein Synopsis Tactile properties of cosmetic products constitute weak stimuli and thus can be expected to be easily modified by mental images. In order to enhance an intended positive-emotion-inducing effect of such a product, its experience can be embedded in a certain ,world' that generates a positive emotional imagination. The present study investigated such an influence in 12 males and 12 females, half of each being laymen and experts in sensory assessment. Two product worlds (emotional and technical) and three different hair samples, two of them treated with different shampoos and an untreated one as control, were presented to each subject in counter-balanced order of all six combinations. An objective emotional assessment using a psychophysiological technique developed in an earlier study was applied and compared with a traditional sensory assessment. Among the physiological measures, peripheral blood volume and facial muscular activity were the most sensitive in revealing effects of and interactions between the product worlds and hair samples. A multivariate evaluation of the physiological data revealed three discriminant functions that explained 78.4% of the total variance and enabled a re-classification considerably better than chance. The first discriminant function clearly separated the treated from the untreated hair samples which was not possible by subjective ratings or traditional sensory assessment. The two other discriminant functions comprised a hedonistic and a product world factor. The emotional product world exerted the largest influence in case of the weakest tactile differences between the hair samples, and its influence was larger on laymen than on experts. Gender effects were most prominent in the subjective domain. In conclusion, multivariate psychophysiological methodology is superior to traditional sensory assessment in revealing subtle differences in the tactile perception of cosmetic products. Résumé Les propriétés tactiles des produits cosmétiques constituent de faibles stimuli, de sorte que l'on peut s'attendre à ce qu'elles soient facilement modifiées par des images mentales. Afin d'intensifier l'effet intentionnellement incitant à une émotion positive envers un tel produit, son expérience peut être introduite dans un certain ,environnement' qui engendrerait une imagination émotionelle positive. La présente étude a testé telle influence sur 12 hommes et 12 femmes, la moitié de chaque groupe étant noninitiée et l'autre experte en évaluation sensorielle. Nous avons présentéà chaque sujet, par ordre contrebalancé des six possibilités, deux ,environnements' du produit (émotif et technique), et trois différents échantillons capillaires dont deux où les cheveux étaient traités par différents shampooings, et, pour le contrôle, un échantillon de cheveux nontraités. Nous avons employé une évaluation émotionelle objective par une technique psychophysiologique développée durant une étude précédente et l'avons comparée à une évaluation sensorielle traditionnelle. Parmi les mesures physiologiques, le volume sanguin périphérique et les activités des muscles faciaux étaient exceptionnellement sensibles à manifester les effets des ,environnements' du produit, et des échantillons, ainsi que les interactions entre eux. Une évaluation multivariante des données physiologiques dévoila trois fonctions discriminantes expliquant les 78.4% de l'ensemble de la variance, et permettant une re-classification considérablement meilleure que le hasard. La première fonction discriminante a nettement distingué les échantillons de cheveux traités de ceux nontraités; ce qui n'était pas possible à travers une évaluation subjective ou des mesures sensorielles traditionnelles. Les deux autres fonctions discriminantes comportaient un facteur hédoniste et d'environnement du produit. Dans le cas des plus faibles différences tactiles entre les échantillons capillaires, l'environnement émotif du produit a exercé plus d'influence sur les noninitiés que sur les experts. Les effets du genre humain étaient surtout marquants dans le domaine subjectif. En conclusion, pour dévoiler les subtiles différences dans la perception tactile des produits cosmétiques, la méthodologie psychophysiologique multivariante est supérieure à l'évaluation sensorielle traditionnelle. [source] Endothelial barriers: from hypothetical pores to membrane proteins*JOURNAL OF ANATOMY, Issue 6 2002J. A. Firth Abstract The anatomical counterpart of the physiologically defined small pore system of capillary endothelia has proved difficult to establish. In non-brain continuous capillaries, the contributions of caveolar and transmembrane pathways are likely to be small and paracellular clefts are probably the dominant routes. Analogy with epithelial paracellular pathways suggests that tight junctions may be the most restrictive elements. However, structural features of tight junction-based models are incompatible with physiological data; it is more likely that the tight junction acts as a shutter limiting the available cleft area. Proposed molecular sieves elsewhere in the paracellular pathway include the glycocalyx and the cadherin-based complexes of the adherens junctions. The molecular architecture of tight junctions and adherens junctions is moderately well defined in terms of molecular species, and there are differences at both sites between the endothelial and epithelial spectra of protein expression. However, definition of the size-restricting pore remains elusive and may require structural biology approaches to the spatial arrangements and interactions of the membrane molecular complexes surrounding the endothelial paracellular clefts. [source] Role of Citrobacter amalonaticus and Citrobacter farmeri in dissimilatory perchlorate reductionJOURNAL OF BASIC MICROBIOLOGY, Issue 2 2004Nirmala Bardiya The article deals with the novel physiological function of dissimilatory perchlorate reduction by strains JB101 and JB109 isolated from a laboratory-enriched mixed consortium originating from a sewage treatment facility. The biochemical and physiological data of the strains showed good correspondence with members of the family Enterobacteriaceae. The partial 16S rDNA sequence of the strains JB101 and JB109 had similarity of 99.8% to Citrobacter amalonaticus and 98% to Citrobacter farmeri, respectively. The results inferred the possibility of Citrobacter spp. to form an important group of dissimilatory perchlorate reducers among the , subclass of Proteobacteria, since the majority of the perchlorate reducers belong to two monophyletic groups, Dechloromonas and Dechlorosoma in , subclass. The perchlorate-grown Citrobacter strains preferred perchlorate to nitrate as an electron acceptor unlike most of the reported dissimilatory perchlorate reducers. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Genetic, physiologic and ecogeographic factors contributing to variation in Homo sapiens: Homo floresiensis reconsideredJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2006GARY D. RICHARDS Abstract A new species, Homo floresiensis, was recently named for Pleistocene hominid remains on Flores, Indonesia. Significant controversy has arisen regarding this species. To address controversial issues and refocus investigations, I examine the affinities of these remains with Homo sapiens. Clarification of problematic issues is sought through an integration of genetic and physiological data on brain ontogeny and evolution. Clarification of the taxonomic value of various ,primitive' traits is possible given these data. Based on this evidence and using a H. sapiens morphological template, models are developed to account for the combination of features displayed in the Flores fossils. Given this overview, I find substantial support for the hypothesis that the remains represent a variant of H. sapiens possessing a combined growth hormone,insulin-like growth factor I axis modification and mutation of the MCPH gene family. Further work will be required to determine the extent to which this variant characterized the population. [source] Regulation of endogenous human NPFF2 receptor by neuropeptide FF in SK-N-MC neuroblastoma cell lineJOURNAL OF NEUROCHEMISTRY, Issue 2 2006Minna-Liisa Änkö Abstract Neuropeptide FF has many functions both in the CNS and periphery. Two G protein-coupled receptors (NPFF1 and NPFF2 receptors) have been identified for neuropeptide FF. The expression analysis of the peptide and receptors, together with pharmacological and physiological data, imply that NPFF2 receptor would be the primary receptor for neuropeptide FF. Here, we report for the first time a cell line endogenously expressing hNPFF2 receptor. These SK-N-MC neuroblastoma cells also express neuropeptide FF. We used the cells to investigate the hNPFF2 receptor function. The pertussis toxin-sensitive inhibition of adenylate cyclase activity upon receptor activation indicated coupling to Gi/o proteins. Upon agonist exposure, the receptors were internalized and the mitogen-activated protein kinase cascade was activated. Upon neuropeptide FF treatment, the actin cytoskeleton was reorganized in the cells. The expression of hNPFF2 receptor mRNA was up-regulated by neuropeptide FF. Concomitant with the receptor mRNA, the receptor protein expression was increased. The homologous regulation of hNPFF2 receptor correlates with our previous results in vivo showing that during inflammation, the up-regulation of neuropeptide FF mRNA precedes that of NPFF2 receptor. The regulation of hNPFF2 receptor by NPFF could also be important in the periphery where neuropeptide FF has been suggested to function as a hormone. [source] Rapid Screening Method of Cassava Cultivars for Resistance to Colletotrichum gloeosporioides f.sp. manihotisJOURNAL OF PHYTOPATHOLOGY, Issue 1 2002C. N. FOKUNANG An in vitro method for assessing cassava anthracnose disease (CAD) resistance was developed as a preliminary screen to a CAD-resistant breeding programme. Potato dextrose agar (PDA) media was amended by extracts from the stem cortex of 10 cassava cultivars (30001; 30572, 30211, 88/02549, 88/00695, 88/01336, 91/00344, 91/00313, 91/00684 and 91/00475), and assayed for efficacy of inhibition of the growth of Colletotrichum gloeosporioides f. sp. manihotis isolates (05FCN, 10FCN, 12FCN, and 18FCN). Morphological and physiological data indicated that there was a significant difference (P , 0.05), in mycelial growth, spore germination and sporulation among the four isolates on PDA amended with cassava stem extracts. Extracts from cassava cultivars 30211, 91/00684 and 91/00313 showed higher inhibition of germ tube development, mycelial growth and sporulation of the fungal isolates, whereas cultivars 88/02549 and 88/01336 showed the least inhibition. The 10 cultivars were further tested in both greenhouse and field conditions, under disease pressure for two planting seasons, to corroborate resistance to the fungus as observed in vitro. Greenhouse and field trials with the 10 cassava cultivars showed a significant difference (P , 0.05) in CAD resistance. Cultivars 88/02549 and 88/01336 were highly CAD-susceptible, as shown in the in vitro assays and confirmed in the greenhouse and field tests. The other eight cultivars were either resistant (30211, 91/00684), or moderately resistant (30572, 88/00695, 91/00475, 91/00344, 30001 and 91/00313) to CAD. The study shows that an in vitro screening assay of cassava for resistance to CAD could serve as a convenient preliminary screening technique to discriminate CAD-resistant from CAD-susceptible cassava cultivars. The in vitro screening method considerably reduces time and labour in comparison with the current screening techniques of cassava, which involve field planting, inoculation and evaluation. [source] Respiration can be monitored by photoplethysmography with high sensitivity and specificity regardless of anaesthesia and ventilatory modeACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 8 2005L. Nilsson Background:, Photoplethysmography (PPG) is a non-invasive optical technique used, for instance, in pulse oximetry. Beside the pulse synchronous component, PPG has a respiratory synchronous variation (PPGr). Efforts have been made to utilize this component for indirect monitoring of respiratory rate and volume. Assessment of the clinical usefulness as well as of the physiological background of PPGr is required. We evaluated if anaesthesia and positive-pressure ventilation would affect PPGr. Methods:, We recorded reflection mode PPGr, at the forearm, and the respiratory synchronous changes in central venous pressure (CVP), peripheral venous pressure (PVP) and arterial blood pressure (ABP) in 12 patients. Recordings for each patient were made on three occasions: awake with spontaneous breathing; anaesthetized with spontaneous breathing; and anaesthetized with positive-pressure ventilation. We analyzed the sensitivity, specificity, coherence and time relationship between the signals. Results:, PPGr sensitivity for breath detection was [mean (SD)] >86(21)% and specificity >96(12)%. Respiratory detection in the macrocirculation (CVP, PVP and ABP) showed a sensitivity >83(29)% and specificity >93(12)%. The coherence between signals was high (0.75,0.99). The three measurement situations did not significantly influence sensitivity, specificity or time shifts between the PPGr, PVP, ABP, and the reference CVP signal despite changes in physiological data between measurements. Conclusion:, A respiratory synchronous variation in PPG and all invasive pressure signals was detected. The reflection mode PPGr signal seemed to be a constant phenomenon related to respiration regardless of whether or not the subject was awake, anaesthetized or ventilated, which increases its clinical usefulness in respiratory monitoring. [source] Cell and molecular biology of human olfactionMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2002Nancy E. Rawson Abstract Progress in our understanding of olfactory receptor physiology has progressed greatly over the past 10 years. It has become clear that many anatomical and molecular features of the peripheral aspect of the olfactory system have remained highly conserved across diverse species. Yet, this structure is responsible for conveying a wide variety of information about the environment that is necessary to the successful location of food, mates, and avoidance of danger, and it is thus not surprising that specializations have also evolved to suit the differing needs of different species. While the basic anatomical features reflect those of other mammals, functional studies of human olfactory receptor neurons have revealed physiological features both similar to and differing from those of other mammalian species. This review presents an overview of both the anatomical and physiological data describing the cell and molecular biology of the peripheral human olfactory system and how it functions in health and disease. Microsc. Res. Tech. 58:142,151, 2002. © 2002 Wiley-Liss, Inc. [source] A physiological overview of the genetics of flowering time controlPLANT BIOTECHNOLOGY JOURNAL, Issue 1 2005Georges Bernier Summary Physiological studies on flowering time control have shown that plants integrate several environmental signals. Predictable factors, such as day length and vernalization, are regarded as ,primary', but clearly interfere with, or can even be substituted by, less predictable factors. All plant parts participate in the sensing of these interacting factors. In the case of floral induction by photoperiod, long-distance signalling is known to occur between the leaves and the shoot apical meristem (SAM) via the phloem. In the long-day plant, Sinapis alba, this long-distance signalling has also been shown to involve the root system and to include sucrose, nitrate, glutamine and cytokinins, but not gibberellins. In Arabidopsis thaliana, a number of genetic pathways controlling flowering time have been identified. Models now extend beyond ,primary' controlling factors and show an ever-increasing number of cross-talks between pathways triggered or influenced by various environmental factors and hormones (mainly gibberellins). Most of the genes involved are preferentially expressed in meristems (the SAM and the root tip), but, surprisingly, only a few are expressed preferentially or exclusively in leaves. However, long-distance signalling from leaves to SAM has been shown to occur in Arabidopsis during the induction of flowering by long days. In this review, we propose a model integrating physiological data and genes activated by the photoperiodic pathway controlling flowering time in early-flowering accessions of Arabidopsis. This model involves metabolites, hormones and gene products interacting as long- or short-distance signalling molecules. [source] Quantitative analyses of anatomical and electrotonic structures of local spiking interneurons by three-dimensional morphometry in crayfishTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 3 2001Ryou Hikosaka Abstract We quantitatively investigated the three-dimensional structure of the dendrites of local spiking interneurons using a confocal laser scanning microscope in the terminal abdominal ganglion of crayfish. We also studied their passive membrane properties electrophysiologically using the single-electrode current clamp techniques to analyze their electrotonic structure. All of the local spiking interneurons examined in this study lacked distinctive axonal structure and had a monopolar cell body that was connected with a fine primary process to a thick main segment. Numerous fine secondary processes projected from the main segment in the ganglionic neuropile. The average anatomical length of a secondary process from the main segment to its terminal was 261.9 ± 15.2 ,m. The average input resistance and membrane time constant of local spiking interneurons, obtained from their voltage responses to intracellular injection of step current pulses in the main segment, were 15.2 ± 1.6 M, and 13.9 ± 1.9 msec, respectively. Calculation of the electrotonic length of dendritic processes based on morphological and physiological data obtained in this study revealed that the average electrotonic length of secondary processes in local spiking interneurons was significantly longer than in local nonspiking interneurons, although both types of local interneurons showed apparently similar anaxonic structure. The steady-state voltage attenuation factors for the secondary processes of local spiking interneurons were significantly greater than those of local nonspiking interneurons in both centrifugal and centripetal directions. The larger electrotonic structure of local spiking interneurons compared to that of nonspiking interneurons appears to be compensated for by their excitable dendritic membrane. J. Comp. Neurol. 432:269,284, 2001. © 2001 Wiley-Liss, Inc. [source] Physiological and behavioral effects of social introduction on adult male rhesus macaquesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2008Lara A. Doyle Abstract Pair housing of laboratory macaques is widely considered to lead to positive changes in well-being, yet the process of introduction is viewed as potentially stressful and risk-prone. Behavioral and physiological data were collected on eight adult male rhesus macaques before, during, and after the process of introduction, in order to measure the initial stress of introduction as well as long-term changes in well-being. Socially experienced subjects, all implanted with biotelemetry devices, were studied in five successive phases: baseline (singly housed), 1 day each of protected contact and full contact introduction, post-introduction (1,3 weeks after introduction), and settled pairs (,20 weeks after introduction). One hundred and seventy-six hours of behavioral data and 672,hr of heart rate data were analyzed. Fecal cortisol was also measured for the baseline, post-introduction, and settled pair phases. All introductions were successful and subjects showed no physiological or behavioral signs of stress, such as increased heart rate, abnormal behavior, or psychological indices of distress (depressive/anxiety-related behavior). Agonism was minimal throughout the introduction process and over the subsequent months; only one wound was incurred over the course of the study. Levels of abnormal behaviors, psychological indices of distress, locomotion, inactivity, and affiliation showed improvements within several weeks after introduction; these changes were still present 5,9 months later for the latter two categories. Heart rates during introduction fell significantly in the settled pair phase, and also varied predictably with time of day. Fecal cortisol levels were lower in settled pairs than in single housing. The fact that reductions in abnormal behavior did not persist over the long term may have been confounded by increasing duration of time spent caged. The results of this study may be of practical use for designing and monitoring social introductions and suggest that managers should not dismiss the feasibility of successful pairing of adult male rhesus macaques. Am. J. Primatol. 70:542,550, 2008. © 2008 Wiley-Liss, Inc. [source] Positive reinforcement training affects hematologic and serum chemistry values in captive chimpanzees (Pan troglodytes)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2006Susan P. Lambeth Abstract Positive reinforcement training (PRT) techniques have received considerable attention for their stress reduction potential in the behavioral management of captive nonhuman primates. However, few published empirical studies have provided physiological data to support this position. To address this issue, PRT techniques were used to train chimpanzees (Pan troglodytes) to voluntarily present a leg for an intramuscular (IM) injection of anesthetic. Hematology and serum chemistry profiles were collected from healthy chimpanzees (n=128) of both sexes and various ages during their routine annual physical examinations over a 7-year period. Specific variables potentially indicative of acute stress (i.e., total white blood cell (WBC) counts, absolute segmented neutrophils (SEG), glucose (GLU) levels, and hematocrit (HCT) levels) were analyzed to determine whether the method used to administer the anesthetic (voluntary present for injection vs. involuntary injection) affected the physiological parameters. Subjects that voluntarily presented for an anesthetic injection had significantly lower mean total WBC counts, SEG, and GLU levels than subjects that were involuntarily anesthetized by more traditional means. Within-subjects analyses revealed the same pattern of results. This is one of the first data sets to objectively demonstrate that PRT for voluntary presentation of IM injections of anesthetic can significantly affect some of the physiological measures correlated with stress responses to chemical restraint in captive chimpanzees. Am. J. Primatol. 68:245,256, 2006. © 2006 Wiley-Liss, Inc. [source] Distinct physiological responses of two rice cultivars subjected to iron toxicity under field conditionsANNALS OF APPLIED BIOLOGY, Issue 2 2009R.J. Stein Abstract Iron toxicity is recognised as the most widely distributed nutritional disorder in lowland and irrigated rice, derived from the excessive amounts of ferrous ions generated by the reduction of iron oxides in flooded soils. Rice cultivars with variable degrees of tolerance to iron toxicity have been developed, and cultural practices such as water management and fertilisation can be used to reduce its negative impact. However, because of the complex nature of iron toxicity, few physiological data concerning tolerance mechanisms to excess iron in field conditions are available. To analyse the physiological responses of rice to iron excess in field conditions, two rice cultivars with distinct tolerance to iron toxicity [BR-IRGA 409 (susceptible) and IRGA 420 (tolerant)] were grown in two areas, with a well-established history of iron toxicity (in Camaquã, RS, Brazil) and without iron toxicity (in Cachoeirinha, RS, Brazil). Plants from the susceptible cultivar grown in the iron-toxic site showed lower levels of chlorophylls and soluble proteins (together with higher carbonyl levels) indicating photooxidative and oxidative damage. The toxic effects observed were because of the accumulation of high levels of iron and not because of any indirectly induced shoot deficiency of other nutrients. Higher activities of antioxidative enzymes were also observed in leaves of plants from the susceptible cultivar only in the iron-toxic site, probably as a result of oxidative stress rather than because of specific involvement in a tolerance mechanism. There was no difference between cultivars in iron accumulation in the symplastic and apoplastic space of leaves, with both cultivars accumulating 85,90% of total leaf iron in the symplast. However, susceptible plants accumulated higher levels of iron in low-molecular-mass fractions than tolerant plants. The accumulation of iron in the low-molecular-mass fraction probably has a direct influence on iron toxicity, and the adaptive strategy of tolerant plants may rely on their capacity to buffer the iron amounts present in the low mass fraction, a new parameter to be considered when evaluating tolerance to iron excess in field-cultivated rice plants. [source] When a graph is poorer than 100 words: A comparison of computerised natural language generation, human generated descriptions and graphical displays in neonatal intensive careAPPLIED COGNITIVE PSYCHOLOGY, Issue 1 2010Marian van der Meulen Volunteer staff from a Neonatal Intensive Care Unit (NICU) were presented with sets of anonymised physiological data recorded over approximately 45,minute periods from former patients. Staff were asked to select medical/nursing actions appropriate for each of the patients whose data were displayed. Data were shown in one of three conditions (a) as multiple line graphs similar to those commonly shown on the ward, or as textual descriptions generated by (b) expert medical/nursing staff or (c) computerised natural language generation (NLG). An overall advantage was found for the human generated text, but NLG resulted in decisions that were at least as good as those for the graphical displays with which staff were familiar. It is suggested that NLG might offer a viable automated approach to removing noise and artefacts in real, complex and dynamic data sets, thereby reducing visual complexity and mental workload, and enhancing decision-making particularly for inexperienced staff. Copyright © 2008 John Wiley & Sons, Ltd. [source] Vertical reduction rectoplasty: a new treatment for idiopathic megarectumBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 9 2000Professor N. S. Williams Background The aetiology of idiopathic megarectum is unknown and the results of surgery are often unsatisfactory. Rectal hyposensation is common and poor perception of rectal filling may contribute to the poor evacuatory function. By reducing the capacity of the rectum, it was hypothesized that sensory thresholds to rectal distension and perception of urge to defaecate would be improved. Methods Vertical reduction rectoplasty (VRR) and concomitant sigmoid colectomy was performed on six patients with idiopathic megarectum. Patients were evaluated before and after operation by detailed questionnaire and anorectal physiology. Postoperative rectal compliance was also studied by means of a programmable electronic barostat. Where appropriate, physiological data were compared with those obtained in eight healthy volunteers. Results Bowel frequency increased from a preoperative median of 2·5 to 16 per month after operation. Four patients reported improved rectal perception of the urge to defaecate. Thresholds for defaecatory urge and maximum tolerated volume were significantly reduced following VRR (P < 0·05). Post-VRR rectal compliance was no different from that in healthy volunteers. Colonic transit time decreased significantly after VRR (P < 0·05) and evacuation on proctography increased from a median of 30 per cent to 50 per cent. At a median of 57 weeks' follow-up five of the six patients expressed continued satisfaction with the results. Conclusion VRR is a new approach to the treatment of idiopathic megarectum. Clinical and physiological studies confirm that it can improve sensory feedback and defaecation. The procedure needs further evaluation as the number of patients undergoing the procedure increases. © 2000 British Journal of Surgery Society Ltd [source] | |||||||||||||||||||||||||