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PubMedDate not supplied

Clinical decision making by nurses when faced with third-space fluid shift. How well do they fare?

Nurses' use of knowledge, the connection of this knowledge to treatment decisions and information actually used to reach such decisions, delineates nurses' level of expertise. Previous research has shown that nurses in their clinical decision-making use the hypothetico-deductive method and intuitive judgment or pattern recognition. This interpretive study explored experienced critical care nurses' (n = 5) and gastrointestinal surgical nurses' (n = 5) clinical decision-making processes through ascertaining their knowledge and understanding of third-space fluid shift in elderly patients undergoing major gastrointestinal surgery. Both groups of nurses, because of their experience with elderly patients undergoing gastrointestinal surgery, were assumed to be experts. Data collection techniques included semi-structured interviews and the use of think aloud protocol for clinical scenario analysis. The findings demonstrated that the gastrointestinal surgical nurses used the hypothetico-deductive method to recognize critical cues and the existence of a problem but could not name the problem. The critical care nurses, on the other hand, used a combination of the hypothetico-deductive method and pattern recognition as a basis for identification of critical cues. The critical care nurses also possessed in depth knowledge of third-space fluid shift and were able to use pivotal cues to identify the actual phenomenon. Ultimately, it would appear that the structure of critical care nurses' work, their increased educational qualifications and the culture of the critical care unit promote a more proactive approach to reasoning in the physiological domain. The findings have implications for the development of practice guidelines and curriculum development in both tertiary and continuing nurse education.

Decision Making↗
PubMed2006

Systemic arterial waveform analysis and assessment of blood flow during extracorporeal circulation.

BACKGROUND: The pressure recording analytical method (PRAM) is a method for real-time beat-to-beat quantification of peripheral blood flow based on the analysis of arterial waveform morphology. Since PRAM can be implemented in any conditions of flow, whether physiological or artificial, we assessed its accuracy in patients undergoing cardiac surgery during extracorporeal circulation (ECC), using the roller-pump device as the reference gold standard. METHODS: We prospectively studied 32 patients undergoing elective coronary surgery. Flow values obtained by PRAM from the radial artery were compared with simultaneous values by thermodilution in physiological conditions of flow and with the roller-pump device readings during ECC. RESULTS: Before and after ECC, the overall estimates of flow measured by PRAM closely agreed with thermodilution (mean difference 0.07 +/- 0.40 L/min). During ECC, PRAM estimates of flow also closely correlated with simultaneous pump readings (mean difference 0.11 +/- 0.33 L/min). At time of weaning from ECC, two patterns of hemodynamic adaptation were documented by PRAM following resumption of cardiac contraction: in most patients (n =26; 80%), cardiac output (CO) was stable (reduction < or = 10% compared to the steady ECC phase); six patients (20%) showed a fall in CO exceeding 10% and up to 38%. CONCLUSIONS: PRAM provided accurate, continuous quantification of peripheral blood flow during each phase of cardiac surgery, including ECC, and allowed early recognition of patients with low CO during weaning from the pump.

Adult↗
PubMed2005

Can an inert sleeping pill affect sleep? Effects on polysomnographic, behavioral and subjective measures.

RATIONALE: Since two recent meta-analyses on sleep changes associated with placebo in clinical trials suggested a beneficial effect of placebo treatments, pointing to a dissociation between subjective and objective measures of sleep, the current experiment was directly aimed to assess the effects of an inert compound, administered with the suggestion that it was a hypnotic substance in subjects with mild sleep complaints. OBJECTIVES: The aim of this study was to compare subjective, behavioral, polysomnographic (PSG), and quantitative electroencephalographic (EEG) changes during a night preceded or not by the intake of two 50-mg lactose capsules. METHODS: Ten female students, selected by the Pittsburgh Sleep Quality Index, slept for three consecutive nights in a sleep laboratory, with the experimental (EXP) night defined by the administration of two 50-mg lactose pills. Self-ratings of sleep quality and performance were assessed upon morning awakening of baseline (BSL) and EXP nights. RESULTS: The EXP nights were self-rated as more restful and characterized by a decreased number of nocturnal awakenings than the BSL nights. PSG measures showed that wakefulness after sleep onset significantly decreased during the EXP night as compared to the BSL night. The EXP nights also showed an increase of 0.5-4.0 Hz power during nonrapid eye movement sleep and a decrease of EEG activity in the beta frequency range during rapid eye movement sleep only at central brain sites. A specific improvement of behavioral measures was also found upon morning awakening after the EXP night compared to the BSL night. CONCLUSIONS: The administration of an inert pill improves both the subjective and objective quality of sleep. The reduced sleep fragmentation and the effects on some quantitative EEG markers of sleep homeostasis suggest that the experimental manipulation induced coherent changes in the subsequent sleep, resembling an enhancement of sleep pressure. The regional differences of EEG activity suggest the involvement of a specific physiological mechanism distinct from that of effective treatments.

Adult↗
PubMed2000

The functional role of oriented spatial filters in the perception of mirror symmetry--psychophysics and modeling.

We investigated human sensitivity to vertical mirror symmetry in noise patterns filtered for narrow bands of variable orientations. Sensitivity is defined here as the amount of spatial phase randomization corresponding to 75% correct performance in a 2AFC detection task. In Experiment 1, sensitivity was found to be high for tests patterns of all orientations except those parallel to the axis of symmetry. This implies that corresponding mirror-orientations (e.g. -45 and +45 degrees ) are combined prior to symmetry detection. In Experiment 2, observers detected symmetry in tests of variable orientation in the presence of either non-symmetric or symmetric masks filtered for orientations either parallel or perpendicular to the axis. Observers were found to be primarily affected by masks of the same orientation as the test, thus suggesting that symmetry is computed separately in distinct mirror-orientation channels. In Experiment 3, observers detected a symmetric test of variable height and width embedded in random noise. Data revealed that mirror symmetry is computed over a spatial integration region (IR) that remains approximately constant in area but whose height-to-width aspect ratio changes from 20:1 to 2:1 as orientation is varied from parallel to perpendicular to the axis. We compare human data against that of an ideal observer to identify key factors that limit visual performance and discuss the implications for the functional architecture of symmetry perception. We also propose a multi-channel model of symmetry detection that combines the output of oriented spatial filters in a simple and physiologically plausible manner. Particular emphasis is placed on the notion that changes in the shape of the IR with orientation compensate for changes in information density and partially equate performance across orientations.

Humans↗
PubMed2026

Rapid transcriptional reprogramming underlies Fusarium wilt resistance in strawberry: insights from comparative physiological and transcriptomic analyses.

INTRODUCTION: Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae (Fof) severely constrains strawberry production, yet the underlying resistance mechanisms remain unclear. METHODS: A total of 64 strawberry germplasm accessions were evaluated for Fusarium wilt resistance. Integrated physiological and transcriptomic analyses were subsequently performed using the highly resistant cultivar 'Akihime' (ZJ) and the highly susceptible cultivar 'Ning Yu' (NY). RESULTS: Resistant resources were abundant, particularly among wild strawberry accessions. Compared with NY, ZJ exhibited higher soluble sugar accumulation, reduced oxidative damage, and increased peroxidase (POD) and phenylalanine ammonia-lyase (PAL) activities. Transcriptomic analyses revealed distinct temporal response patterns: ZJ underwent rapid and extensive transcriptional reprogramming at 24 h post-inoculation, whereas NY showed limited early responses but pronounced changes at 120 h. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that the early response of ZJ was mainly associated with stress-related processes, jasmonic acid-mediated signaling, transmembrane transport, plant-pathogen interaction, mitogen-activated protein kinase (MAPK) signaling, glutathione metabolism, plant hormone signal transduction, and secondary metabolism. Quantitative real-time polymerase chain reaction (qRT-PCR) validation supported the RNA-seq results and identified candidate genes associated with pathogen recognition, signaling, redox regulation, and protein homeostasis. DISCUSSION: These results indicate that rapid early immune activation and coordinated physiological and metabolic reprogramming are closely associated with strawberry resistance to Fof and provide useful germplasm and candidate genes for future functional validation and resistance breeding.

Fusarium oxysporum f. sp. fragariae↗
PubMedDate not supplied

Aging successfully: the importance of physical activity in maintaining health and function.

Physicians caring for middle-aged and older patients frequently overlook the importance of regular physical activity. Exercise on a routine basis is an important component of successful aging. It has been shown that many age-related declines in musculoskeletal function can be markedly reduced by participation in some form of regular exercise. Examination of records from masters athletic competitions has been used to determine the true rate of age-related functional declines in highly trained, healthy individuals and further supports these findings. Declines in physical abilities for masters athletes are gradual, which suggests that for many, the potential for participation in competitive athletics can persist well into the seventh decade of life. Recent studies indicate that health gains can be achieved with relatively low volumes of exercise. Indeed, the greatest benefit is seen when one "goes from doing nothing to doing something." Current data suggest that a cumulative total of 30 to 50 minutes of aerobic exercise a day performed 3 to 5 days a week and one set of resistance exercises targeting the major muscle groups twice a week can produce significant health benefits. The aerobic conditioning requirement need not be a formal or structured activity, but can be satisfied through regular participation in many common physical tasks (e.g., walking, gardening, housekeeping). Musculoskeletal injuries are a major cause of noncompliance with any exercise regimen and are especially debilitating for older individuals. Prompt recognition of injury and treatment that emphasizes alternative conditioning exercises and minimizes "downtime" are especially important. Orthopaedists should be aware of the pattern of musculoskeletal injuries seen in this population, so as to assist their patients in avoiding these problems.

Aged↗
PubMed1991

Receptors for neurohypophyseal hormones along the rat nephron: 125I-labelled d(CH2)5[Tyr(Me)2, Thr4, Orn8, Tyr-NH(2)9] vasotocin binding in microdissected tubules.

A microassay was developed to measure the binding of the labelled monoiodinated analogue [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid), 2-O-methyltyrosine, 4-threonine, 8-ornithine, 9-125I-tyrosylamide]vasotocin [125I-d(CH2)5[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT] to isolated nephron segments microdissected from collagenase-treated rat kidneys. When determined using 1.7 nM labelled ligand at 4 degrees C, specific binding sites (expressed at 10(-18) mol 125I-d(CH2)5[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT bound/mm tubule length) were found in medullary thick ascending limbs (MTAL), 1.67 +/- 0.49; cortical thick ascending limbs, 2.20 +/- 0.80; cortical collecting ducts, 2.39 +/- 0.86; outer medullary collecting ducts (OMCD), 2.54 +/- 0.53 and inner medullary collecting ducts, 5.33 +/- 0.40, whereas no specific binding could be detected in glomeruli and proximal tubules. Specific 125I-d(CH2)5[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT binding to OMCD was saturable with incubation time and reversible after elimination of free labelled ligand (the association and dissociation rate constants at 4 degrees C were 1.06 x 10(7) M-1 min-1 and 1.95 x 10(-2) min-1 respectively). The stereospecificity of MTAL and OMCD binding sites was assessed in competitive experiments revealing the following recognition pattern for a series of eight vasopressin analogues:dDAVP greater than AVP greater than d(CH2)5-[Tyr (Me)2, Thr4, Tyr-NH(2)9]OVT = AVT = OT greater than d(CH2)5[Tyr(Me)2]AVP = [Thr4, Gly7]OT greater than [Phe2, Orn8]VT, whereas pharmacological concentrations of insulin and glucagon did not impair radioligand binding. These results indicate that the detected labelled binding sites might correspond mainly to physiological V2 vasopressin receptors.

Animals↗
PubMed2003

Dynamic regulation of expression of colony-stimulating factor 1 in the reproductive tract of cattle during the estrous cycle and in pregnancy.

Colony-stimulating factor 1 (CSF-1) is a hematopoetic cytokine that also plays an important role in placental physiology. We report here the molecular cloning of two alternative splice variants of the bovine gene coding for a putative secreted and a membrane-bound form of the cytokine and the dynamic regulation of expression in the reproductive tract of cattle during the estrous cycle and pregnancy. Bovine CSF-1 was expressed mainly as the 3- and 4-kilobase (kb) transcripts, but 1.4- and 0.8-kb mRNAs were also detected in Day 50-70 pregnant uterine tissue. During the estrous cycle, both the 4- and 3-kb mRNAs were present, but the 3-kb putative membrane-bound form was more abundant than the 4-kb secreted form during diestrus. This pattern of expression was reversed in pregnancy, so that the exponential increase in CSF-1 expression seen during pregnancy was due predominantly to increased abundance of the 4-kb transcript. The change in the 4-kb:3-kb ratio was detected between Day 14 and Day 17, approximately the time of maternal recognition of pregnancy. Thus, CSF-1 was identified as one gene whose expression in the uterus might be altered early in response to the presence of the conceptus. CSF-1 was also expressed in the extraembryonic membranes of the conceptus and in the trophoblastic cells of the fetal cotyledons after the formation of the placentomes. The high level of CSF-1 expression during bovine pregnancy in uteroplacental tissues is consistent with its proposed role in placental physiology.

3' Untranslated Regions↗
PubMed2001

Interocular rivalry revealed in the human cortical blind-spot representation.

To understand conscious vision, scientists must elucidate how the brain selects specific visual signals for awareness. When different monocular patterns are presented to the two eyes, they rival for conscious expression such that only one monocular image is perceived at a time. Controversy surrounds whether this binocular rivalry reflects neural competition among pattern representations or monocular channels. Here we show that rivalry arises from interocular competition, using functional magnetic resonance imaging of activity in a monocular region of primary visual cortex corresponding to the blind spot. This cortical region greatly prefers stimulation of the ipsilateral eye to that of the blind-spot eye. Subjects reported their dominant percept while viewing rivalrous orthogonal gratings in the visual location corresponding to the blind spot and its surround. As predicted by interocular rivalry, the monocular blind-spot representation was activated when the ipsilateral grating became perceptually dominant and suppressed when the blind-spot grating became dominant. These responses were as large as those observed during actual alternations between the gratings, indicating that rivalry may be fully resolved in monocular visual cortex. Our findings provide the first physiological evidence, to our knowledge, that interocular competition mediates binocular rivalry, and indicate that V1 may be important in the selection and expression of conscious visual information.

Adult↗
PubMed2006

Processing of facial identity and expression: a psychophysical, physiological, and computational perspective.

A deeper understanding of how the brain processes visual information can be obtained by comparing results from complementary fields such as psychophysics, physiology, and computer science. In this chapter, empirical findings are reviewed with regard to the proposed mechanisms and representations for processing identity and emotion in faces. Results from psychophysics clearly show that faces are processed by analyzing component information (eyes, nose, mouth, etc.) and their spatial relationship (configural information). Results from neuroscience indicate separate neural systems for recognition of identity and facial expression. Computer science offers a deeper understanding of the required algorithms and representations, and provides computational modeling of psychological and physiological accounts. An interdisciplinary approach taking these different perspectives into account provides a promising basis for better understanding and modeling of how the human brain processes visual information for recognition of identity and emotion in faces.

Brain↗
PubMed1992

The role of mannose-binding proteins in host defense.

The human mannose-binding protein (MBP) appears to function as an "ante-antibody" as its physiological role is in first line host defense. Low baseline serum levels are rapidly increased as part of the acute phase reactant and circulating MBP can act as a direct opsonin or activate the classical alternative complement pathway. MBP appears to selectively recognize an array of apparently disparate oligosaccharides that decorate gram-negative and gram-positive bacteria as well as certain parasites, yeasts, and fungi. MBP may be considered a "pattern" recognition molecule that has homologs in primitive life forms. Its ability to distinguish self from nonself indicates that it may play an important role in innate immunity.

Amino Acid Sequence↗
PubMed1984

[Computer-assisted monitoring in intensive care].

Computerized intensive care in children and infants is possible. But it requires: 1. a modification and extension of the commercially available soft-ware, 2. a sampling rate of 2 values/min or more [7,8] and 3. the noninvasive measurement of the parameters, especially for long-time recordings. - The graphical presentation of the parameters for a longer time shows typical patterns, which lead to an earlier recognition of critical situations. Thus earlier therapy becomes possible. Other characteristic patterns no doubt will be discovered by further research.

Blood Gas Analysis↗
PubMed2003

An integrated network for invariant visual detection and recognition.

We describe an architecture for invariant visual detection and recognition. Learning is performed in a single central module. The architecture makes use of a replica module consisting of copies of retinotopic layers of local features, with a particular design of inputs and outputs, that allows them to be primed either to attend to a particular location, or to attend to a particular object representation. In the former case the data at a selected location can be classified in the central module. In the latter case all instances of the selected object are detected in the field of view. The architecture is used to explain a number of psychophysical and physiological observations: object based attention, the different response time slopes of target detection among distractors, and observed attentional modulation of neuronal responses. We hypothesize that the organization of visual cortex in columns of neurons responding to the same feature at the same location may provide the copying architecture needed for translation invariance.

Attention↗
PubMed1990

HLA class-I-transgenic mice as model system to study MHC-restricted antigen recognition in man.

In order to develop a possible animal model to study HLA linked diseases of man, we established HLA-B27 transgenic mice (TGM). As aberrant and overexpression of MHC molecules can be toxic for cells, we aimed at obtaining a physiological expression of the human antigen and used a genomic 25kb Sal I fragment for embryo injection, coding for the HLA-B* 2705 heavy chain. Five independent founder mice were obtained containing varying copies of the fragment (1 to 10). RNA analysis from different tissues showed an expression pattern similar to endogenous H-2 class I genes. HLA-B27 antigen could be detected on lymphocytes derived from all five founder mice, even in the absence of human beta 2-microglobulin (hu beta 2m). It was found that the presence of hu beta 2m strongly enhances HLA-B27 cell surface expression in mice with few copies of the transgene, but was not necessary for efficient and high cell surface presentation in the 10 copy line. In all HLA-B27 TGM lines, the HLA molecule functions as restriction element in anti-viral responses. In addition, we could show that T lymphocytes of the transgenic animals respond to the same HLA-B27 restricted influenza peptide as is recognized by human influenza-specific, HLA-B27 restricted cytotoxic T cell lines.

Animals↗
PubMed1981

The irritable bowel syndrome. A clinical review and ethical considerations.

The irritable bowel syndrome (IBS) is clinically characterized by a wide variety of symptoms, including dyspepsia, flatulence, nausea, cramping abdominal pain, constipation and/or diarrhea, and nonspecific symptoms, probably reflecting autonomic nervous system overreactivity. Physiologically, the colonic motor abnormality is characterized by an altered slow-wave rhythm, quantitative differences from normal in the repetitive contraction pattern of the rectosigmoid area, and increased colonic muscle responsiveness to hormones such as cholecystokinin and pentagastrin. The diagnosis of IBS involves practical and ethical considerations as well as the need for decisive reassurance of the patient through judicious examination. Treatment of IBS requires a thoughtful and sensitive approach to the patient, recognition of IBS as an important clinical problem, regularization of bowel function, relief of the abdominal discomfort, and intelligent emotional support.

Attitude of Health Personnel↗
PubMed1998

Definition of the transcriptional activation domains of three human HOX proteins depends on the DNA-binding context.

Hox proteins control developmental patterns and cell differentiation in vertebrates by acting as positive or negative regulators of still unidentified downstream target genes. The homeodomain and other small accessory sequences encode the DNA-protein and protein-protein interaction functions which ultimately dictate target recognition and functional specificity in vivo. The effector domains responsible for either positive or negative interactions with the cell transcriptional machinery are unknown for most Hox proteins, largely due to a lack of physiological targets on which to carry out functional analysis. We report the identification of the transcriptional activation domains of three human Hox proteins, HOXB1, HOXB3, and HOXD9, which interact in vivo with the autoregulatory and cross-regulatory enhancers of the murine Hoxb-1 and human HOXD9 genes. Activation domains have been defined both in a homologous context, i.e., within a HOX protein binding as a monomer or as a HOX-PBX heterodimer to the specific target, and in a heterologous context, after translocation to the yeast Gal4 DNA-binding domain. Transfection analysis indicates that activation domains can be identified in different regions of the three HOX proteins depending on the context in which they interact with the DNA target. These results suggest that Hox proteins may be multifunctional transcriptional regulators, interacting with different cofactors and/or components of the transcriptional machinery depending on the structure of their target regulatory elements.

Amino Acid Sequence↗
PubMed2003

Implicit learning deficit in children with developmental dyslexia.

Several neuropsychological deficits have been reported as characteristic of the cognitive profile of dyslexic children. Phonological and visual processing are often impaired as well as auditory processing, attention and information processing speed. We investigated whether implicit learning, is impaired in dyslexic children and adolescents. Tests of implicit and declarative learning were administered to 18 clinically defined dyslexics and 18 similar age controls. Dyslexics showed a reduced learning rate in the implicit but not in the declarative task, suggesting a specific deficit of implicit learning. Although alternative hypothesis cannot be ruled out, considering that implicit learning is a cognitive function primarily processed by the cerebellum and that recent neurological and physiological data suggest a cerebellar dysfunction in dyslexia, the present results suggest an impairment of cerebellar system in reading disabilities.

Analysis of Variance↗
PubMed1999

Modelling spatial contrast sensitivity functions for chromatic and luminance-modulated gratings.

We extended our detection model of achromatic spatial vision (Rovamo, J., Mustonen, J., & Näsänen, R. (1994a). Modelling contrast sensitivity as a function of retinal illuminance and grating area. Vision Research, 34, 1301-1314) to colour vision by taking into account the fact that due to the spatio-chromatic opponency of retinal ganglion cells and dorsal lateral geniculate nucleus (dLGN) neurons, equiluminous chromatic gratings are not affected by precortical lateral inhibition. We then tested the extended model by using Mullen's experimental data (Mullen, K. J. (1985). The contrast sensitivity of human color vision to red-green and blue-yellow chromatic gratings. Journal of Physiology, 359, 381-400). The band-pass shape of the spatial contrast sensitivity function for luminance-modulated green and yellow gratings transformed to a low-pass shape, resembling the chromatic spatial contrast sensitivity function for red-green and blue-yellow equiluminous gratings, when the effect of precortical lateral inhibition on grating contrast was computationally removed by dividing luminance contrast sensitivities by spatial frequency (i.e. by af, where a = 1 degree). After the removal of this direct effect of lateral inhibition, there still remained a residual shape difference between the spatial contrast sensitivity functions for chromatic and luminance gratings. It was due to indirect reduction of grating visibility by quantal noise high-pass filtered by precortical lateral inhibition. When this indirect effect of quantal noise was also removed, contrast sensitivity for luminance gratings was about twice the sensitivity for chromatic gratings at all spatial frequencies. This was evidently due to the fact that the chromatic contrast of the equiluminous grating at the opponent stage (Cole, G. R., Hine, T. & McIihagga, W. (1993). Detection mechanisms in L-, M-, and S-cone contrast space. Journal of the Optical Society of America A, 10, 38-51) was about half of the luminance contrast of either of its chromatic component. Thus, if the contrast of the equiluminous chromatic grating were not expressed as the Michelson contrast of one chromatic component grating against its own background (Mullen, K. J. (1985). The contrast sensitivity of human color vision to red-green and blue-yellow chromatic gratings. Journal of Physiology, 359, 381-400) but as chromatic contrast at the opponent stage, contrast sensitivity would be the same for chromatic and luminance gratings.

Color Perception↗