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PubMed1976

Culture, adaptation, and patterns of disease.

The sick patient, rather than the disease process itself, should occupy the central focus of the physician's attention. Such an approach recognizes the interaction of physiologic and emotional forces in the occurrence of disease. It allows for a consideration of the contributory role of emotions in the precipition of physical illness and a recognition that physical illness may produce emotional sequelae of relevance to the total clinical problem. It is an approach which views man as an adapting animal, whose environment may play a crucial role in his adaptation and his disease. Only with such a perspective of man and disease can the principles of medical treatment be realistic.

Abortion, Induced↗
PubMed2001

Menstrual cycle variation in spatial ability: relation to salivary cortisol levels.

This study examined whether menstrual cycle phase was associated with performance on the Primary Mental Abilities Test of Spatial Relations, a test of mental rotation, in undergraduate students (N = 82). As cortisol levels also vary across the menstrual cycle under conditions of stress and influence cognitive performance, saliva samples were obtained before and after the test session to examine whether cortisol levels were related to between- and within-group differences in spatial performance. Men scored higher on the spatial test than all the groups of women, although the difference between men and women in the menstrual phase was not significant. Women in the luteal phase scored lower than the menstrual, follicular, and oral contraceptive user groups of women. There were no sex or menstrual cycle differences in cortisol levels, and no association between cortisol levels and spatial performance. The poorer performance of women in the luteal phase was not related to differences in ratings of perceived stress, perceived success on the test, or mood. Although menstrual cycle phase accounted for a significant proportion of the variance (15%) in performance on the spatial test, this does not explain why men outperformed women regardless of the phase of the cycle. Thus, there are clearly several other variables, sociocultural and physiological, involved in mediating individual differences in spatial performance.

Adolescent↗
PubMed2006

The spatial extent of lateral interactions in flicker perception.

We investigated the influence of the relative phase of a temporally modulated annulus on the perceived flicker strength of a center stimulus having the same temporal modulation. These measurements were performed in two subjects at two temporal frequencies and with different outer diameters of the annulus. The perceived flicker strength was strongly modulated by the phase difference between center and surround stimulus. This modulation depended on the size of the annulus. In the absence of an annulus the perceived flicker strength was not modulated. The modulation initially increased with increasing annulus size and reached a plateau. The space constant of the function describing the modulation as a function of annulus size was about 0.5 degrees and is similar to the sizes of receptive field surrounds of subcortical cells. This finding is in favor of the hypothesis that the physiological basis of the perceived flicker strength in the center stimulus is present already at a subcortical level.

Adult↗
PubMed1997

Somatostatin: the neuroendocrine story.

Since its original discovery as the neuroendocrine hormone responsible for inhibiting growth hormone (GH) secretion, our understanding of the functions of somatostatin [or somatotrophin release inhibitory hormone (SRIH)], both in the periphery and the CNS, has grown enormously. With the cloning of five SRIH receptors, much interest has centred recently on the potential use of SRIH analogues in the treatment of clinical conditions ranging from human cancers to Alzheimer's and Parkinson's diseases. There is a growing recognition that the physiological functions of GH also need to be extended beyond its role in growth control, e.g. to a role in the maintenance of normal immune, cardiovascular and reproductive functions. Here, Glenda Gillies addresses the importance of somatostatinergic systems in regulating the sexually dimorphic patterns of GH secretion as well as their influence on other endocrine hormones. She also considers the neurotransmitter/neuromodulator actions of SRIH within the hypothalamus, where it is involved in the neural control and integration of many aspects of endocrine function, as well as its potential role in the maturation of the hypothalamus during the critical perinatal period.

Animals↗
PubMed2006

Individual time-dependent spectral boundaries for improved accuracy in time-frequency analysis of heart rate variability.

Heart rate variability (HRV) is a major noninvasive technique for evaluating the autonomic nervous system (ANS). Use of time-frequency approach to analyze HRV allows investigating the ANS behavior from the power integrals, as a function of time, in both steady-state and non steady-state. Power integrals are examined mainly in the low-frequency and the high-frequency bands. Traditionally, constant boundaries are chosen to determine the frequency bands of interest. However, these ranges are individual, and can be strongly affected by physiologic conditions (body position, breathing frequency). In order to determine the dynamic boundaries of the frequency bands more accurately, especially during autonomic challenges, we developed an algorithm for the detection of individual time-dependent spectral boundaries (ITSB). The ITSB was tested on recordings from a series of standard autonomic maneuvers with rest periods between them, and the response to stand was compared to the known physiological response. A major advantage of the ITSB is the ability to reliably define the mid-frequency range, which provides the potential to investigate the physiologic importance of this range.

Algorithms↗
PubMed2006

Immunologic quantitation of tissue factors.

The large number of conflicting reports on the presence and concentration of circulating tissue factor (TF) in blood generates uncertainties regarding its relevance to hemostasis and association with specific diseases. We believe that the source of these controversies lies in part in the assays used for TF quantitation. We have developed a highly sensitive and specific double monoclonal antibody fluorescence-based immunoassay and integrated it into the Luminex Multi-Analyte Platform. This assay, which uses physiologically relevant standard and appropriate specificity controls, measures TF antigen in recombinant products and natural sources including placenta, plasma, cell lysates and cell membranes. Comparisons of reactivity patterns of various full-length and truncated TFs on an equimolar basis revealed quantitative differences in the immune recognition of TFs by our antibodies in the order of TF 1-263 > 1-242 > 1-218 > placental TF. Despite this differential recognition, all TF species are quantifiable at concentrations < or = 2 pM. Using a calibration curve constructed with recombinant TF 1-263 and plasma from healthy individuals (n = 91), we observed the concentration of TF antigen in plasma to be substantially lower than that generally reported in the literature: TF antigen in plasma of 72 individuals (79%) was below 2 pM (quantitative limit of our assay); TF antigen levels between 2.0 and 5.0 pM could be detected in six individuals (7%); and in 14% (13 plasmas), the non-specific signal was higher than the specific signal, and thus TF levels could not be determined. These differential recognition patterns affect TF quantitation in plasma and should be considered when evaluating plasma TF-like antigen concentrations.

Antibodies, Monoclonal↗
PubMed1994

Reproducibility and intraindividual variability of the pattern electroretinogram.

The human pattern electroretinogram (PERG) is a contrast-specific potential presumedly reflecting the functional integrity of ganglion cells. Many studies have devised criteria that enable PERG measurements to distinguish established glaucomatous (hypertonic) eyes from normal controls. As there are relatively few reports concerning the reproducibility and reliability of the PERG, we studied the intraindividual variability of the PERG in 20 healthy subjects. Both transient and steady-state responses were recorded using a high-contrast (98%), black-and-white, counterphasing checkerboard pattern (average luminance, 80 cd/m2) generated by a television monitor (subtending angle, 13.8 degrees x 10.8 degrees) using three different check sizes (15', 30', and 60'). Recordings were performed in both eyes simultaneously at a 7-day interval under test-retest conditions. Responses of 30' spatial frequency were most consistent and resulted in a mean amplitude (+/- SD) of 2.18 +/- 0.95 microV (P50) and 4.00 +/- 1.69 microV (N95) for transient patterns and 1.84 +/- 1.25 microV for steady-state patterns. No statistically significant difference was observed between either right and left eyes, test and retest conditions or 1st- and 7th-day recording sessions for PERG parameters. In linear correlation analysis there was an adequate, positive correlation between the right and left eyes (r = 0.78); a weak correlation between test and retest conditions (r = 0.58); and no correlation between measurements made at a 7-day interval. As a consequence, we conclude that the follow-up of patients (e.g., glaucoma, ocular hypertension) by means of PERG is critical, especially when therapeutic consequences may be based on the physiological variability of a weak retinal signal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Effect of speed of development on mRNA expression pattern in early bovine embryos cultured in vivo or in vitro.

Recent data have demonstrated that fast-cleaving embryos produced in vitro are more likely to develop to blastocyst stage, and that the postfertilization culture system used impacts considerably on the mRNA expression and quality of blastocysts produced. The present study is the first to investigate the relationship between the developmental speed of embryos produced in vivo or in vitro and the temporal transcription pattern. Genes related to important preimplantation events are monitored during the first 4 days of embryo development in embryos with fast or slow development. The set of genes analyzed in the present study characterizes several important physiological processes including: transport and metabolism of fructose (Glut-5), stress (SOX), mitochondrial activity and detoxification of reactive oxygen species (MnSOD), cell communication (Cx43), maternal recognition of pregnancy (IFN-tau), imprinting (IGF-II), apoptosis (Bax), growth factor binding and metabolism (IGF-IR), and oxidative stress (G6PD). Using real time PCR, we have found that for all the genes analyzed there are differences in mRNA expression between embryos with fast and slow developmental speed produced both in vitro and in vivo. Frequently, genes that may be stress induced such as SOX, MnSOD, BAX, IFtau, and G6PD were highly transcribed in in vitro produced embryos and in embryos with slow developmental speed. On the other side, transcripts from genes related with metabolism, growth, and differentiation (Glut-5, Cx 43, IGF-II, and IGF-IR) were detected in higher amounts in in vivo produced embryos and in embryos with fast developmental speed. Moreover, it is interesting to stand out that for some genetic markers (such as SOX and G6PD) there are in vivo and in vitro differences that can be observed even before materno-zygotic transition, which probably reflects a differential mRNA degradation. These transcription patterns reflects the embryonic response to the adverse in vitro culture conditions, and connect the low quality of embryos which slow developmental speed produced in vivo and in vitro, with the mRNA expression pattern of some embryonic genes.

Animals↗
PubMed2002

The use of physiological data to corroborate cospeciation events in symbiosis.

The symbiotic association between sepiolid squids (Family Sepiolidae) and luminous bacteria (Genus Vibrio) provides an unusually tractable model to study the evolution and speciation of mutualistic partnerships. Both host and symbiont can be cultured separately, providing a new avenue to test phylogenetic congruence through molecular and physiological techniques. Combining both molecular and morphological data as well as measuring the degree of infectivity between closely related pairs can help decipher not only patterns of co-speciation between these tightly linked associations, but can also shed new light on the evolution of specificity and recognition among animal-bacterial associations.

Animals↗
PubMed1990

Regional differences in the distribution of endogenous receptors for carbohydrate constituents of cellular glycoconjugates, especially lectins, in cortex, hippocampus, basal ganglia and thalamus of adult human brain.

Ten different types of labelled neoglycoproteins, exposing glycohistochemically pivotal carbohydrate moieties that mostly are constituents of naturally occurring glycoconjugates with an aromatic spacer, were synthesized. The panel was applied to fixed, paraffin-embedded sections of different cortical regions and white matter, of hippocampal gyrus, basal ganglia, thalamus nuclei and adjacent areas of adult human brain to comprehensively map the presence of respective binding sites in these parts. Compliance with accepted criteria for specificity of binding was routinely ascertained. Overall, not a uniform binding pattern, but a distinct distribution with regional differences on the level of specific cytoplasmic and nuclear staining in nerve cells was determined, fiber structures being generally labelled with medium or strong intensity. For example, among the neurons localized in the five cortical laminae the binding of N-acetyl-D-galactosamine varied from strong to undetectable. Biochemical analysis, employing carbohydrate residues as affinity ligands in chromatography, proved that the neuroanatomically different regions exhibited a pattern of receptors with notable similarities. These results on endogenous binding sites for glycoconjugates, especially lectins, are complementary to assessment of localization of cellular glycoconjugates by plant lectins and carbohydrate-specific monoclonal antibodies. They are thus a further obligatory step to substantiate the physiological roles of recognitive protein-carbohydrate interactions in the central nervous system.

Adult↗
PubMed2025

Systematic Review of Symptoms of Catatonia in Autism Spectrum Disorder.

Catatonia is a complex neuropsychiatric syndrome characterized by disturbances in mood, motor function, behavior and speech. It is increasingly recognized in individuals with autism spectrum disorder (ASD), although its identification remains challenging due to the overlapping clinical features of the two conditions. Shared characteristics, such as echophenomena, mannerisms, social indifference and repetitive behaviors can obscure accurate diagnosis. Although reports suggest a significant prevalence of catatonia among individuals with ASD, the condition remains poorly understood and frequently under recognized, leading to substantial diagnostic and treatment challenges. A systematic review was conducted to characterize the symptoms of catatonia in individuals with ASD. The literature search included peer-reviewed journal articles published in English from 1980 onward, focusing on studies examining co-occurring catatonia and ASD. A qualitative framework analysis was implemented to evaluate 45 peer-reviewed studies, with findings interpreted in relation to, and extending beyond, the diagnostic criteria for catatonia outlined in the International Classification of Diseases, 11th revision (ICD-11). The objective was to identify symptom patterns extending beyond current diagnostic frameworks and to support improved clinical recognition and diagnostic precision in ASD populations. The review identified six primary symptom clusters associated with catatonia in individuals with ASD: (1) psychomotor activity, (2) speech disturbances, (3) changes in behavior/skills/functions, (4) mental health symptoms, (5) physiological symptoms, and (6) symptoms related to arousal and awareness. Notably, several symptoms observed within these clusters are not currently included in the ICD-11 diagnostic criteria for catatonia. These additional symptoms include tics, motor compliance, incoherent speech, self-injury, impaired cognition, and appetite changes, suggesting a broader clinical presentation of catatonia in ASD populations than is presently captured in existing diagnostic frameworks. The findings of this review highlight the significance of enhancing clinicians' awareness and understanding of how catatonia manifests in individuals with ASD. Most notably, six symptom clusters, psychomotor changes, speech disturbances, behavioral and functional regression, affective and psychiatric symptoms, physiological symptoms, and arousal/awareness disturbances, were observed. Several symptoms identified in this review are not included in the current diagnostic criteria, and their recognition may facilitate in earlier identification and timely intervention, potentially preventing the severe consequences of untreated catatonia in this population.

Humans↗
PubMed2003

Modes and clustering for time-warped gene expression profile data.

MOTIVATION: The study of the dynamics of regulatory processes has led to increased interest for the analysis of temporal gene expression level data. To address the dynamics of regulation, expression data are collected repeatedly over time. It is difficult to statistically represent the resulting high-dimensional data. When regulatory processes determine gene expression, time-warping is likely to be present, i.e. the sample of gene expression trajectories reflects variation not only in terms of the expression amplitudes, but also in terms of the temporal structure of gene expression. RESULTS: A non-parametric time-synchronized iterative mean updating technique is proposed to find an overall representation that corresponds to a mode of a sample of expression profiles, viewed as a random sample in function space. The proposed algorithm explores the application of previous work of Hall and Heckman to genome-wide expression data and provides an extension that includes random time-warping with the aim to synchronize timescales across genes. The proposed algorithm is universally applicable for the construction of modes for functional data with time-warping. We demonstrate the construction of mode functions for a sample of Drosophila gene expression data. The algorithm can be applied to define clusters among the observed trajectories of gene expression, without any kind of prior non-time-warped clustering, as illustrated in the numerical example.

Adaptation, Physiological↗
PubMed1997

Individual recognition by heart rate variability of two different autonomic profiles related to posture.

BACKGROUND: Power spectrum analysis of heart rate variability (HRV) can estimate the state of sympathovagal balance modulating sinus node activity. In view of the large distribution of spectral variables, a recognition of well-defined physiological conditions has never been attempted on an individual basis. METHODS AND RESULTS: We considered 10 spectral variables extracted from short segments (200 to 500 cardiac cycles) of 350 ECG tracings recorded in normal subjects in both supine and upright positions (700 patterns). The tracings were first ordered consecutively and subsequently assigned alternatively to a training or to a test set (each consisting of 175 cases, providing 350 patterns considered to be independent). A forecasting linear method estimated a normalized activation index (ranging from -1 for supine to +1 for upright) that concentrated the information derived from spectral variables and that identified, in the test set, individual by individual, approximately 84% of corresponding body postures. CONCLUSIONS: The combined use of spectral methodology and forecasting analysis has revealed an information content embedded, per se, in a short series of RR intervals capable of recognizing, individual by individual, two different autonomic profiles related to posture.

Adolescent↗
PubMed2004

Effects of alcohol on verbal processing: an event-related potential study.

BACKGROUND: Behavioral studies suggest that alcohol intoxication impairs the speed and accuracy of word recognition and categorization, but alcohol's effects on the brain during verbal cognitive processing are not adequately understood. Using event-related potentials (ERP) and a word-recognition paradigm, this study investigated the effects of alcohol intoxication on prelexical, semantic, and mnemonic aspects of verbal processing. METHODS: Concurrent measures of ERPs and skin conductance responses were obtained in a word-repetition priming task and permitted a comparison of the effects of alcohol on the central and autonomic physiologic systems. Social drinkers participated in all four cells of the within-subjects balanced placebo design, in which the effects of alcohol and information as to the beverage content (expectancy) were manipulated. The average peak blood alcohol level peaked at 0.045%. RESULTS: None of the manipulations affected behavioral performance, and expectancy had no effect on any of the measures. In contrast, alcohol ingestion attenuated the temporoparietal N180, suggesting an impairment in prelexical pattern-recognition processes. Alcohol significantly increased the amplitude of N450 and the latency of P580, particularly on trials evoking sympathetic arousal as measured with skin conductance responses. CONCLUSIONS: Although behavioral measures were unaffected, ERPs showed that a moderately low alcohol dose affected verbal processing during both early, prelexical and late, semantic stages. Alcohol significantly increased the difficulty of semantic access and integration, as reflected in larger N450 amplitude and longer P580 latency. This effect was particularly prominent on arousal-related trials, suggesting that alcohol impairs processes that modulate cognitive functioning. The lack of an interaction between the factors of repetition and beverage suggests that a moderately low alcohol dose exerts these effects via the semantic and integration systems rather than via memory processes.

Adult↗
PubMed1999

Temporal profile of visual evoked responses to pattern-reversal stimulation analyzed with a whole-head magnetometer.

Magnetoencephalography (MEG) has become accepted as a useful method for non-invasively studying brain functions, including visual perception. The present study used MEG to elucidate information processing following pattern-reversal stimulation by analyzing the origins and properties of visual evoked magnetic fields (VEFs). The VEFs of ten healthy adults were recorded in a magnetically shielded room using a 122-channel whole-head magnetometer. The visual stimulation of checkerboard-pattern reversal at 1.7 Hz was presented to the subject's right hemifield. Visual evoked potentials (VEPs) were recorded simultaneously, and 150 responses were each averaged for VEFs and VEPs. For the contrast profile study, pattern-reversal stimuli at five different contrast levels from 96% to 8% were used. In all subjects, the VEFs showed three components with latencies of approximately 95, 120, and 160 ms. The equivalent current dipoles for the first and the third components were located and were oriented close to each other in the left occipital lobe, but these dipoles were separated from that of the second component, which showed an opposite direction. Stimuli at a moderate contrast level markedly reduced the first component, but not the third. These findings indicate that the first and the third components of VEFs appear to originate from anatomically closely situated, almost identical, sources, but that their physiological properties differ.

Adult↗
PubMed1997

Habituation-like effects cause a significant decrease in response in MRI neuroactivation during visual stimulation.

A wide range of rest/stimulus cycle durations (40-360 sec) is reported to have been used by various groups for MRI neuroactivation studies of the visual cortex. In this paper we demonstrate a clear habituation-like response for longer cycle durations which results in a halving of apparent activation between cycle durations of 138 and 276 sec. This has important implications, not only in terms of optimizing the technique, but also in providing an insight into the underlying physiological mechanisms.

Adult↗
PubMed1994

Sex differences in the left and right hemifields of normal subjects with computerised static perimetry.

Results of routine perimetric testing of the left and right hemifields in normal subjects have been assumed to be symmetric although asymmetry due to hemispheric dominance has been established for other psychophysical tests. These asymmetries have sometimes been related to sex. With the advent of computerised static perimetry, subtle differences between the left and the right hemifields might be found that were not obvious before. This study investigated differences in retinal sensitivity between the hemifields and the role of sex and eye dominance. Forty three unequivocally right handed and right eye dominant normal adult volunteers, 24 females and 19 males, underwent Humphrey 24-2 testing, half beginning with the left eye, the other half with the right eye. The Peridata program was used to calculate decibel totals per hemifield. Four subjects were excluded because of poor cooperation or test artefacts. In females, the total of the left hemifield was significantly less than the right (p < 0.01) by a mean 18.2 (SD 24) dB equivalent to a difference of 0.34 dB per tested point. No significant difference in hemifields was found for males, between the sexes for both eyes combined, or between the two eyes for either sex. It was concluded that asymmetries in retinal sensitivity with respect to the vertical axis may be physiological and found in females, but not in males.

Adult↗
PubMed2006

Characterization of surface EMG signals using improved approximate entropy.

An improved approximate entropy (ApEn) is presented and applied to characterize surface electromyography (sEMG) signals. In most previous experiments using nonlinear dynamic analysis, this certain processing was often confronted with the problem of insufficient data points and noisy circumstances, which led to unsatisfactory results. Compared with fractal dimension as well as the standard ApEn, the improved ApEn can extract information underlying sEMG signals more efficiently and accurately. The method introduced here can also be applied to other medium-sized and noisy physiological signals.

Algorithms↗