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PubMedDate not supplied

Still confused about rose bengal?

We have surveyed the ophthalmic literature of the last five years in an attempt to evaluate the use and usefulness of Rose Bengal staining as an aid to differential diagnosis in dry eyes. Included both as a criterion and as an adjunct measure of disease progression, Rose Bengal scores of patients with different dry eye conditions overlap, sometimes to a considerable extent. A mechanistic link between staining with this dye and disease etiology is unlikely; however, Rose Bengal could be a surrogate marker of changes in ocular surface physiology. The question whether the extent and pattern of staining with Rose Bengal provide the clinician with information not available from other tests, and in particular from fluorescein staining of the ocular surface, has to be answered positively, though the nature of this information is not clearly understood. A more widespread recognition that Rose Bengal is not a vital dye is necessary in order not to bias the interpretation of experimental results.

Biomarkers↗
PubMed1990

Electrophysiological evidence for parallel and serial processing during visual search.

Event-related potentials were recorded from young adults during a visual search task in order to evaluate parallel and serial models of visual processing in the context of Treisman's feature integration theory. Parallel and serial search strategies were produced by the use of feature-present and feature-absent targets, respectively. In the feature-absent condition, the slopes of the functions relating reaction time and latency of the P3 component to set size were essentially identical, indicating that the longer reaction times observed for larger set sizes can be accounted for solely by changes in stimulus identification and classification time, rather than changes in post-perceptual processing stages. In addition, the amplitude of the P3 wave on target-present trials in this condition increased with set size and was greater when the preceding trial contained a target, whereas P3 activity was minimal on target-absent trials. These effects are consistent with the serial self-terminating search model and appear to contradict parallel processing accounts of attention-demanding visual search performance, at least for a subset of search paradigms. Differences in ERP scalp distributions further suggested that different physiological processes are utilized for the detection of feature presence and absence.

Adolescent↗
PubMedDate not supplied

[The electrophysiologycal and information aspects of stress development].

In the first part of this paper the modern concepts of stress and possibility of diagnostics of early stress manifestations are considered. Though significant advances of researches of this problem many methodological and methodical aspects are continued to be discussed. The categorical proff are stage development of adaptation processes and there classification [H. Selye]. A long-term studies of adaptation processes of students in semesters and exams have been conducted by authors with specially development and to accumulate new data. The second part of this paper is the survey of these results published in different time. The polyparametric technology including some electrophysiological methods with the system analysis using artificial intelligence algorithms and methods of pattern recognition permitted to show some regular dependences in relationships of electrophysiological parameters and there variations under stress development. It was shown for diagnostics of stress stages in necessary to assess not only absolute values of parameters but also there relationships, which are new diagnostics signs considering as information connections between physiological systems. The main characteristic of functional state of an organism is balance of parameter's relationships in totality, representing invariant for healthy persons. In condition of disharmony of parameter relationships there are aroused the strain, overstrain functional state or failure of adaptation in depends on a degree of misbalance. The represented new data don't contradict to known reasons and mechanisms of stress and accumulated data of its variety manifestations. As the work-hypothesis the information-wave model of appearance of psychosomatic reactions of stress is introduced.

Electrophysiology↗
PubMed2002

NMR-based metabonomic studies on the biochemical effects of commonly used drug carrier vehicles in the rat.

The biochemical effects of a series of commonly used drug carrier vehicles were investigated using (1)H NMR spectroscopic and pattern recognition based metabonomic analysis. Animals were treated by oral gavage with six dosage vehicles: 0.5% (w/v) sodium carboxymethylcellulose/0.2% (v/v)tween; microemulsion (consisting of propylene glycol, ethanol, cremophor, and corn oil glycerides); labrafil [consisting of poly(ethylene glycol) 300 esterified with oleic acid] (30%)/corn oil (70%); 0.1 M sodium phosphate buffered water; poly(ethylene glycol) 300 and 0.5% methocel. Urine samples (n = 7) collected over a 96 h period post administration were analyzed using 600 MHz (1)H NMR spectroscopy, and principal components analysis of the spectral data was used to analyze these data. Of the six vehicles studied, three (labrafil/corn oil, PEG 300 and microemulsion) gave rise to strong vehicle-related signals in the (1)H NMR spectra of urine and were, therefore, deemed to be less suitable for NMR-based toxicity studies. To investigate any biochemical consequences of vehicle dosing, PCA was used to analyze spectral regions that did not contain vehicle-related signals, i.e., the NMR-detectable endogenous metabolite profile. PEG 300 and labrafil/corn oil induced changes in the biochemical composition of urine including increased concentrations of dicarboxylic acids, creatinine, taurine, and sugars, indicating that these vehicles were bioactive in their own right and that this might confound interpretation of biochemical effects of weakly toxic drugs dosed in these carriers. This study shows the importance of selecting appropriate vehicles for NMR-based metabonomic studies with a view to minimizing the possibility of vehicle resonances obscuring endogenous compound peaks. Furthermore, we have shown that at least two of the commonly used drug carrier vehicles caused metabolic perturbations in the urine profile. These alterations in the biochemical profile reflect vehicle-induced changes in the physiological status of the organism that may obscure the pharmacologic or toxicologic effects of drugs.

Administration, Oral↗
PubMed1998

Neuromonitoring in the operating room: why, when, and how to monitor?

This review considers the main principles and indications of EEG and evoked potential (EP) neuromonitoring in the operating room. Neuromonitoring has a threefold purpose: to warn the surgeon that he has to adjust his strategy, to confirm his decision, and to help him improve subsequent procedures. The pathophysiology of intraoperative events liable to alter the EEG or the EPs is first considered. The usefulness of neuromonitoring in preventing neurological complication relies on its ability to detect neurological dysfunction at a reversible stage. This applies especially to ischemia and compressive damage. The anesthetic influences on EEG and EPs are then considered. Knowledge of them is essential to disentangle these neurophysiological alterations due to intraoperative events from those merely due to anesthesia and to use neurophysiological parameters to evaluate the depth of anesthesia. Third, the main indications and limitations of neuromonitoring are considered: prevention of ischemic brain or spinal cord damage, prevention of mechanical injuries of the brain, spinal cord or peripheral nerve, and localization of the motor cortex in cortical neurosurgery or of cranial nerves in posterior fossa surgery. Finally, the 3 levels of neuromonitoring (neurophysiological feature extraction, neurophysiological pattern recognition, clinical integration of the neurophysiological patterns) are discussed together with the rules that should guide the dialogue between the surgeon, the anesthesiologist, and the neurophysiologist.

Anesthesia↗
PubMed1990

Effect of contrast on the perceived direction of a moving plaid.

We performed a series of experiments examining the effect of contrast on the perception of moving plaids. This was done to test the hypothesis put forth by Adelson and Movshon (1982) that the human visual system determines the direction of a moving plaid in a two-staged process: decomposition into component motion followed by application of the intersection of constraints rule. Although there is recent evidence that the first tenet of their hypothesis is correct, i.e. that plaid motion is initially decomposed into the motion of the individual grating components (Movshon, Adelson, Gizzi & Newsome, 1986; Welch, 1989), the nature of the second-stage combination rule has not as yet been established. We found that when the gratings within the plaid are of different contrast, the perceived direction is not predicted by the intersection of constraints rule. There is a strong (up to 20 deg) bias in the direction of the higher-contrast grating. A revised model, which incorporates a contrast-dependent weighting of perceived grating speed as observed for 1-D patterns (Thompson, 1982), can quantitatively predict most of our results. We discuss our results in the context of various models of human visual motion processing and of physiological responses of neurons in the primate visual system.

Adolescent↗
PubMed1998

Comparison of pattern-onset, -reversal and -offset VEPs in treated amblyopia.

PURPOSE: There are differences in the properties of visual evoked potentials (VEPs) to various forms of pattern stimulation and it is not clear how these differences reflect macular and parmacular function in amblyopic and normal eyes. We assessed pattern-onset, -reversal and -offset VEPs from amblyopic eyes and compared them with the responses from the fellow eyes, and from controls, to gauge the relative effectiveness of these stimulus modes. METHODS: The three modes of pattern stimulation were presented sequentially in a single recording run to enable direct comparisons to be made for identical recording conditions. Half-field stimulation was used, as this elicits components over the ipsilateral and contralateral occipital scalp relative to the stimulated half-field, which reflect stimulation of macular and paramacular areas of the visual field. Eighteen amblyopes treated by occlusion and 20 control children were studied. RESULTS: Multivariate analysis of variance showed significant differences between ambylopic and fellow eyes in amblyopes: pattern-onset components were significantly attenuated and ipsilateral reversal components were significantly prolonged in amblyopic eyes. When fellow eyes of amblyopes were compared with the eyes of controls, the reversal P100 and offset P110 and N165 components showed significant differences. CONCLUSIONS: Ipsilateral reversal components and onset CII and contralateral P105 were the most affected in amblyopic eyes. The subnormal findings for the fellow eyes of amblyopes suggest that occlusion may have a long-standing physiological effect on the patched eye, not normally clinically apparent.

Adolescent↗
PubMed1987

Intraneural microstimulation in man. Its relation to specificity of tactile sensations.

Recent advances in knowledge, and controversy, concerning cutaneous mechanoreception are reviewed. In particular, the question of perceptive specificity is discussed in the light of new experimental approaches, namely microneurography and microstimulation of identified tactile units from the glabrous skin of the human hand. Additional data are also presented. It is concluded that the human brain has an exquisite capacity to detect, localize, delineate, and classify sensations from the input of individual tactile units in the glabrous skin of the hand. The physiological specificity of low-threshold mechanoreceptors in the hand, which has been well documented in previous studies, can now be linked to distinct attributes of very simple tactile sensations which subjects report when a single afferent is stimulated electrically through an intraneural microelectrode. This conclusion does not conflict with the concept that the brain normally makes use of temporal and spatial patterns of impulses from a large number of receptors of various types to form more complex tactile percepts, such as in the recognition of texture, but the microstimulation data demonstrate that particular patterns of nerve impulses are not a necessary determinant of the subjective quality attribute of a simple tactile sensation. On the contrary, the sensations elicited by a train of impulses in a single afferent unit are remarkably distinct and well characterized in a number of respects. A further conclusion is that the afferent inputs are processed differently in tactile subsystems. This observation warrants caution in generalizing results from one system into a common theory of the origin of sensory modality.

Electric Stimulation↗
PubMed2006

Training-induced plasticity in older adults: effects of training on hemispheric asymmetry.

The extent to which cortical plasticity is retained in old age remains an understudied question, despite large social and scientific implications of such a result. Neuroimaging research reports individual differences in age-related activation, thereby educing speculation that some degree of plasticity may remain throughout life. We conducted a randomized longitudinal dual-task training study to investigate if performance improvements (a) change the magnitude or pattern of fMRI activation, thereby suggesting some plasticity retention in old age and (b) result in a reduction in asymmetry and an increase in age differences in fMRI activation as a compensatory model of performance-related activation predicts. Performance improvements were correlated with an increase in hemispheric asymmetry and a reduction in age differences in ventral and dorsal prefrontal activation. These results provide evidence for plasticity in old age and are discussed in relation to an alternative argument for the role of reduced asymmetry in performance improvements.

Adaptation, Physiological↗
PubMed1992

Elucidation of the sequence-specific third-strand recognition of four Watson-Crick base pairs in a pyrimidine triple-helix motif: T.AT, C.GC, T.CG, and G.TA.

We report a specific pattern of recognition by third-strand bases for each of the four Watson-Crick base pairs within a pyrimidine triple-helix motif as determined by PAGE: T.AT, C.GC, T.CG, and G.TA. Our recognition scheme for base triplets is in agreement with previous studies. In addition, we identified another triplet, T.CG, under physiological conditions, in which formation of triple helix was observed at equimolar ratios of the third strand and duplex target. Although different nearest-neighbor effects are expected, this finding extends the base-recognition code to all 4 base pairs in double-stranded DNA under physiological conditions. Base-composition analysis of putative triplex species provided independent evidence for the formation of triplex and confirmed the base-recognition code determined by PAGE. Moreover, the formation of triplex, as detected by gel electrophoresis, was seen to be an all-or-none phenomenon, dependent upon a single-base mismatch among 21 nucleotides. This result suggests a high specificity for the recognition of double-stranded DNA by a third strand. In addition, we report the surprising finding that triplex stability depends on the length and sequence of the target duplex DNA.

Base Composition↗
PubMed1992

Carnivorous plants: phylogeny and structural evolution.

The carnivorous habit in flowering plants represents a grade of structural organization. Different morphological features associated with the attraction, trapping, and digestion of prey characterize a diversity of specialized forms, including the familiar pitcher and flypaper traps. Phylogenetic analysis of nucleotide sequence data from the plastic rbcL gene indicates that both carnivory and stereotyped trap forms have arisen independently in different lineages of angiosperms. Furthermore, these results demonstrate that flypaper traps share close common ancestry with all other trap forms. Recognition of these patterns of diversification may provide ideal, naturally occurring systems for studies of developmental processes underlying macromorphological evolution in angiosperms.

Base Sequence↗
PubMed2005

Clinical advances in the diagnosis and therapy of the interstitial lung diseases.

The last century experienced remarkable advances in the classification, diagnosis, and understanding of the pathogenesis of the interstitial lung diseases. Technological advances, particularly physiologic testing, lung imaging studies, bronchoalveolar lavage, surgical lung biopsy, and histopathologic assessment, improved our understanding of these entities. In particular, the advent of high-resolution computed tomography, the narrowed pathologic definition of usual interstitial pneumonia, and recognition of the prognostic importance of separating usual interstitial pneumonia from other idiopathic interstitial pneumonia patterns have profoundly changed the approach to these processes. Most recently, genetic medicine, the use of new technologies (e.g., microarrays, mass spectroscopic analysis of proteins, and laser capture microdissection), and the development of animal models have had a major impact on understanding the pathogenesis and potential molecular targets for interfering with fibrogenesis. This article highlights some of the advances and changes in clinical practice that took place in the management of patients with interstitial lung diseases over the last century.

Humans↗
PubMed1992

[Improved learning capacity and discrimination performance of neural networks in pattern recognition of biosignals].

Pattern recognition was an important goal in the early work on artificial neural networks. Without arousing dramatic speculation, the paper describes, how a "natural" method of dealing with the configuration of the input layer can considerably improve learning behaviour and classification rate of a modified multi-layered perception with backpropagation of the error learning rule. Using this method, recognition of complex patterns in electrophysiological signals can be performed more accurately, without rules or complicated heuristic procedures. The proposed technique is demonstrated using recognition of the J-point in the ECG as an example.

Electrocardiography↗
PubMed2003

Chemical cues from Murgantia histrionica eliciting host location and recognition in the egg parasitoid Trissolcus brochymenae.

Host location and recognition by the egg parasitoid Trissolcus brochymenae were analyzed in terms of response to kairomones from several stages of its host, Murgantia histrionica. In a Y-tube olfactometer, parasitoid females responded by increasing residence time and/or reducing linear speed to chemical cues from gravid females, virgin females and males, fifth and third instars, and eggs. In an open arena, T. brochymenae females also responded to patches contaminated by chemicals from the host in the same stages, sexes, and/or physiological conditions as those tested in the olfactometer. The parasitoid displayed arrestment behavior, increased residence time, changed walking pattern, and intense substrate examination. When host egg clusters or glass dummies with a chemical egg extract were placed on the host-contaminated open arena, these elicited an orientation response in the parasitoid. In addition, the chemical egg extract without dummies elicited the same response, whereas dummies without extract did not influence parasitoid behavior. In a closed arena, the parasitoid females recognized and attempted to probe glass beads treated with chemical extracts of host eggs. There were no significant differences compared with their response to the host eggs, and they did not respond to untreated beads. Host recognition was elicited by chemicals from the follicular secretion used by the host to glue the eggs on the substrate. These results are discussed in relation to the level of the host selection sequence influenced by these cues.

Animals↗
PubMedDate not supplied

[The combined pattern of physiologic and relation dynamic processes in long-term encopresis].

The treatment of a case of encopresis of six years duration in a boy now ten years of age demonstrates how physiological and dynamical processes in personal relationships combine in a common evolution. Through this the encopresis has become chronic and has lead to other instances of developmental retardation in the form of inadequate school performance. The fundamental concept behind the psychotherapeutical treatment stems from the recognition of an inner connection between the current symptoms, the chronic nature of the disease and the lack of success of previous disciplinary, medical and psychotherapeutical attempts at a solution.

Child↗
PubMedDate not supplied

Effects of emotional valence and arousal manipulation on eyeblink classical conditioning and autonomic measures.

Using a classical eyeblink conditioning paradigm, we have previously shown that the rate of acquisition of a conditioned response may be manipulated by engaging subjects in background tasks of varying complexity concurrent to conditioning. To further examine the influence of the background environment on conditioning, a picture set designed to elicit emotional responses, the International Affective Picture System (IAPS), was presented to subjects during classical eyeblink conditioning. The results suggest that eyeblink conditioning does appear to be sensitive to contextual manipulations of arousal. Pictures rated as very arousing were found to engage subjects enough to enhance learning, although not to the point that autonomic functions were significantly altered between picture groups. We suggest that group differences in learning may be a result of either novelty of, or vigilance to, interesting pictures rather than as a direct result of physiological arousal.

Adolescent↗
PubMed1987

Effect of pattern luminance profile on the pattern ERG in man and pigeon.

Pattern electroretinograms (PERGs) have been recorded in man and pigeon using phase reversing patterns. Studies were made in both species of the effect of grating spatial frequency, grating profile (sine or square) or the size of the squares of a checkerboard on the amplitude of the responses. The results obtained in the two species were similar. In general, the ratio of the amplitudes of the sine wave:square wave responses is that predicted by the Fourier fundamentals of the pattern, and is thus not determined by changes in local luminance or contrast as it is normally defined. Checks however gave larger responses than sine or square wave profile bars matched to the Fourier fundamental on the diagonal. The results are not explicable in terms of any single stimulus parameter and suggest that the PERG generator has a degree of center/surround organisation similar to retinal ganglion cells. It is however argued that, because of the known physiological properties, generators cannot be unequivocally localised by varying the stimulus or comparing retinal, cortical and perceptual response dynamics.

Animals↗
PubMed1998

Evolution in functional complexity of heart rate dynamics: a measure of cardiac allograft adaptability.

The capacity of self-organized systems to adapt is embodied in the functional organization of intrinsic control mechanisms. Evolution in functional complexity of heart rate variability (HRV) was used as measure of the capacity of the transplanted heart to express newly emergent regulatory order. In a cross-sectional study of 100 patients after (0-10 yr) heart transplantation (HTX), heart rate dynamics were assessed using pointwise correlation dimension (PD2) analysis. A new observation is that, commencing with the acute event of allograft transplantation, the dynamics of rhythm formation proceed through complex phase transitions. At implantation, the donor heart manifested metronome-like chronotropic behavior (PD2 approximately 1.0). At 11-100 days, dimensional complexity of HRV reached a peak (PD2 approximately 2.0) associated with resurgence in the high-frequency component (0.15-0.5 Hz) of the power spectral density. Subsequent dimensional loss to PD2 approximately 1.0 at 20-30 mo after HTX was followed by a progressive near-linear gain in system complexity, reaching PD2 approximately 3.0 7-10 yr after HTX. The "dynamic reorganization" in the allograft rhythm-generating system, seen in the first 100 days, is a manifestation of the adaptive capacity of intrinsic control mechanisms. The loss of HRV 2 yr after HTX implies a withdrawal of intrinsic autonomic control and/or development of an entrained dynamic pattern characteristic of extrinsic sympathetic input. The subsequent long-term progressive rise in dimensional complexity of HRV can be attributed to the restoration of a functional order patterning parasympathetic control. The recognition that the decentralized heart can restitute the multidimensional state space of HR generator dynamics independent of external autonomic signaling may provide a new perspective on principles that constitute homeodynamic regulation.

Adaptation, Physiological↗