SEARCH · PubMed Health

Results for “Pattern Recognition, Physiological”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,189 records · Page 66Linked to original sources

PubMed1995

Nutritional aspects of breast cancer.

Nutrition, in its broadest sense, plays a clear role in breast cancer, identified through its relationship to such known risk factors as rate of growth and development, age at menarche, adult height, postmenopausal body weight, and fat distribution. The relative importance of daily diet is hotly debated. There is no agreement on the relative importance of nutrition's effect, the responsible food groups and nutrients, nor the age or ages at which it can be influential. Evidence linking breast cancer and diet comes from human ecologic and observational studies as well as a body of experimental feeding studies in rats and mice. The population studies, including increasing numbers of migrant studies, and the animal experiments suggest that high-fat diets promote breast cancer, particularly among older women. Studies that compare diets of persons with and without breast cancer and those that record breast cancer incidence among women with different dietary histories have been inconclusive enough as to warrant randomized intervention trials. Recognition of differences between the risk factors for premenopausal and postmenopausal women and increasing insight into the ages at which known risk factors exert their influence have helped in the design of these trials. Human feeding studies and the trials themselves are identifying metabolic changes and their biomarkers as well as biomarkers for changes in fat and nutrient intakes. The Women's Health Initiative Dietary Modification Trial was designed to show whether a sustained (9-year) low-fat, high-fruit-and-vegetable eating pattern will lower the incidence of breast cancer among women who will be between ages 59 and 88 when the trial ends, the time of peak incidence. Meanwhile, the Women's Intervention Nutrition Study will learn in approximately 5 years whether a low-fat, adjuvant eating pattern will improve the prognoses of postmenopausal women with early and moderate stage breast cancer and whether tamoxifen should be used as at least part of their treatment. The results of these trials will have important applications for both public health and the provision of medical care.

Adult↗

PubMed1985

A hemodynamic profile diagram and its application in septic patients.

A physiologic profile is presented in the form of a circular diagram, in which hemodynamic parameters, oxygen uptake and arterial lactate are displayed on 12 radial spokes. Results are presented as per cent of reference values. In the normal state the profile will be evenly circular, while different circulatory disturbances present typical patterns. This is shown in serial measurements on 12 septic patients, who displayed increases in cardiac output, oxygen metabolism, stroke volume, heart rate, pulmonary artery pressure, right atrial pressure, pulmonary capillary wedge pressure and arterial lactate, while pulmonary and systemic vascular resistances were decreased. Stepwise multiple regression analysis indicated that systemic vascular resistance was the best early discriminator between survivors and non-survivors. The hemodynamogram offers a compact and easily understood presentation of data, which makes it possible to follow the course of the disease and provides a diagnostic and didactic tool.

Adult↗

PubMed1997

Gamma delta T cells of the murine vagina: T cell response in vivo in the absence of the expression of CD2 and CD28 molecules.

While little is known about their activation requirements and function, the intraepithelial T cells of the murine vagina express TCR complexes in which the antigen recognition components and the signaling components have unusual features. These vaginal T cells express an invariant V gamma 4/V delta 1 TCR and appear to be the only intraepithelial gamma delta T cells that exclusively use FcR gamma chains in their TCR complex. To further characterize the vaginal gamma delta T cells we isolated them from normal mice and from mice injected systemically with an activation-inducing dose of anti-TCR mAb. The isolated gamma delta T cells were examined by flow cytometry for their surface expression of a panel of adhesion, proteins, activation antigens and cellular interaction molecules (CD44, CD62L, CD45RB, LFA-1, CD2 and CD28). The patterns of expression observed indicate that the vaginal gamma delta T cells of normal mice show the phenotype of effector T cells. The adhesion/co-stimulatory molecules CD28 and CD2 were not detected on vaginal gamma delta T cells, an interesting finding since the absence of CD2 from other T cells has been suggested to result in anergy. However, vaginal gamma delta T cells are responsive to TCR-mediated signals since injection of normal mice with pan-anti-TCR antibody or stimulating anti-gamma delta TCR antibody resulted in an increase in cell number and increased expression of transferrin and IL-2 receptors. These results indicate that vaginal gamma delta T cells might utilize other co-stimulatory molecules, if any, in connection with TCR-induced activation and differentiation. While the physiological function of vaginal gamma delta T cells remains unknown, the expression of an invariant V gamma 4/V delta 1 TCR, their exclusive use of gamma chain homodimers in their TCR, and the absence of CD2 and CD28 co-stimulatory molecules are a novel combination of properties that suggests specialized functional properties. Although vaginal gamma delta T cells share some features in common with gamma delta T cells that reside in other epithelial tissues, such as skin and intestine, the present studies provide additional evidence that vaginal gamma delta T cells are a highly specialized and distinct T cell population.

Animals↗

PubMed2003

Visual performance in monosodium glutamate-treated rats.

The purpose of this study was to examine the effect of monosodium glutamate on the visual performance in rats. The Wistar strain of neonatal rats were injected subcutaneously with a solution of the glutamate at doses of 1 or 2 or 4 mg/gm body weight on days 2, 4, 6, 8 and 10 postnatally. Control rats received an injection of physiological saline. At 1, 2 and 3 months of age, the rats were tested for visual performance (brightness discrimination, pattern discrimination and visual acuity). As a result, the 4 mg/gm glutamate treatment was observed to impair brightness discrimination performance at 1 month of age as compared to the control animals. This impairment was also observed in animals at 2 and 3 months as compared, in addition, to the values in other doses of glutamate treatment. Pattern discrimination performance in every group of animals was at the same level at 1 month of age. However, at 2 months of age, the performance in the 2- and 4 mg/gm glutamate-treated groups was lower than those in the control group. This comparison was more pronounced at 3 months of age. Visual acuity performance results were quite the same as the pattern discrimination performance at all ages of animals. In conclusion, glutamate treatment was shown to cause dose-dependent deficit in visual performance and this may reflect impairment of visual organs and brain function.

Aging↗

PubMed1999

What pattern the eye sees best.

The visibility of gratings improves with increasing stimulus area. This effect is usually interpreted as being due to physiological summation within the extent of the largest spatial filter and due to probability summation between the outputs of linear, independent filters beyond that range. It is generally assumed that this improvement is isotropic to the patch configuration. In contrast, the existence of long-range facilitation that is configuration-specific suggests that the visibility of a local contrast is dependent on the spatial configuration of the stimuli. We measured contrast thresholds for circular and elongated Gabor patches with a static carrier. The patch envelope orientation was either the same as the bar orientation (collinear) or orthogonal to it. Contrast sensitivity was highest for elongated configurations that were collinear with the grating bars, and reached maximal efficiency at a length of about four grating cycles (eight bar widths), but a width of only one cycle.

Contrast Sensitivity↗

PubMed1997

The horizontal optokinetic reflex of the opossum (Didelphis marsupialis aurita): physiological and anatomical studies in normal and early monoenucleated specimens.

In the opossum the symmetrical binocular horizontal optokinetic nystagmus gives way to an asymmetrical monocular reflex: the nasotemporal (NT) stimulation yielding lower gain than the temporonasal (TN). In adults, monocularly enucleated at postnatal days 21-25 (pnd21-25), the gain of NT responses is markedly increased, approaching that of TN. Severe cell loss was detected in the nucleus of the optic tract (NOT) on the deafferented side in early monoenucleated specimens. In normal animals retinal afferents to the NOT are all crossed, while in animals enucleated at pnd21-25 sparse uncrossed retinal elements were observed. Although this abnormal projection might influence the increased NT response in this subgroup, it is argued that the increased symmetry in monoenucleated opossums may be the result of changes mediated by the commissural connection between both NOTs.

Animals↗

PubMed2003

A physiological theory of depth perception from vertical disparity.

It has been known since the time of Helmholtz that vertical differences between the two retinal images can generate depth perception. Although many ecologically and geometrically inspired theories have been proposed, the neural mechanisms underlying the phenomenon remain elusive. Here we propose a new theory for depth perception from vertical disparity based on the oriented binocular receptive fields of visual cortical cells and on the radial bias of the preferred-orientation distribution in the cortex. The theory suggests that oriented cells may treat a vertical disparity as a weaker, equivalent horizontal disparity. It explains the induced effect, and the quadrant and size dependence of vertical disparity. It predicts that horizontal and vertical disparities should locally enhance or cancel each other according to their depth signs, and that the effect of vertical disparity should be orientation dependent. These predictions were confirmed through psychophysical experiments.

Depth Perception↗

PubMed1993

Cortical connections of inferior temporal area TEO in macaque monkeys.

In macaque monkeys, lesions involving the posterior portion of the inferior temporal cortex, cytoarchitectonic area TEO, produce a severe impairment in visual pattern discrimination. Recently, this area has been shown to contain a complete, though coarse, representation of the contralateral visual field (Boussaoud, Desimone, and Ungerleider: J. Comp. Neurol. 306:554-575, '91). Because the inputs and outputs of area TEO have not yet been fully described, we injected a variety of retrograde and anterograde tracers into 11 physiologically identified sites within TEO of seven rhesus monkeys and analyzed the areal and laminar distribution of its cortical connections. Our results show that TEO receives feedforward, topographically organized inputs from prestriate areas V2, V3, and V4. Additional sparser feedforward inputs arise from areas V3A, V4t, and MT. Each of these inputs is reciprocated by a feedback projection from TEO. TEO was also found to have reciprocal intermediate-type connections with the fundus of the superior temporal area (area FST), cortex in the most posteromedial portion of the superior temporal sulcus (the posterior parietal sulcal zone [area PP]), cortex in the intraparietal sulcus (including the lateral intraparietal area [area LIP]), the frontal eye field, and area TF on the parahippocampal gyrus. The connections with V3A, V4t, and PP were found only after injections in the peripheral field representations of TEO. Finally, TEO was found to project in a feedforward pattern to area TE and to areas anterior to FST on the lateral bank and floor of the superior temporal sulcus (areas TEm, TEa, and IPa, Seltzer and Pandya: Brain Res. 149:1-24, '78), all of which send feedback projections to TEO. Feedback projections also arise from parahippocampal area TH, and areas TG, 36, and possibly 35. These are complemented by only sparse feedforward projections to TG from central field representations in TEO and to TH from peripheral field representations. The results thus indicate that TEO forms an important link in the occipitotemporal pathway for object recognition, sending visual information forward from V1 and prestriate relays in V2-V4 to anterior inferior temporal area TE.

Animals↗

PubMed2001

The development of postganglionic sympathetic neurons: coordinating neuronal differentiation and diversification.

The fine-tuned operation of the nervous system is accomplished by a diverse set of neurons which differ in their morphology, biochemistry and, consequently, their functional properties. The accurate interconnection between different neuron populations and their target tissues is the prerequisite for physiologically appropriate information processing. This is exemplified by the regulatory action of the autonomic nervous system in vertebrates to sustain homeostasis under changing physiological demands. For this purpose, the coordination of divergent regulatory responses is required in a multitude of tissues spread over the entire body. To meet this task, diverse neuronal populations interact at different levels. In the sympathetic system. chemical relations between preganglionic and postganglionic neurons appear to differ along the rostrocaudal axis. In addition, postganglionic neurons innervating different target tissues at a segmental level have distinct properties. Differences in their preganglionic innervation and their integrative membrane properties result in diverse activation patterns upon reflex stimulation. Moreover, postganglionic neurons differ in the transmitter molecules they employ to convey information to the target tissues. The segregation of noradrenaline and acetylcholine to different populations of postganglionic sympathetic neurons is well established. A combination of cellular and molecular approaches has begun to uncover how such a complex system may be generated during development. Growth and transcription factors involved in noradrenergic and cholinergic differentiation are characterised. Interestingly, they can also promote the expression of proteins involved in transmitter secretion. As the proteins participating in the vesicle cycle are expressed in many neuron populations, whereas the enzymes of transmitter biosynthesis are restricted to subpopulations of neurons, the findings suggest that early in neuronal development subpopulation-specific and more widely expressed neuronal properties can be commonly induced. Still, many details concerning the signals involved in the induction of the neurotransmitter synthesis and release machinery remain to be worked out. Likewise, the regulatory processes resulting in differences of electrophysiological membrane properties and the specific recognition between pre- and postganglionic neurons have to be determined. Ultimately, this will lead to an understanding at the molecular level of the development of a nervous system with diverse neuronal populations that are specifically interconnected to distinct input neurons and target tissues as required for the performance of a complex regulatory function.

Animals↗

PubMed1995

Change in locomotor activity pattern in mice: a model for recognition of distress?

Recognition and assessment of pain and distress is made by observing common clinical and behavioural signs. Observation usually occurs during a limited period of time and results can be biased by interpretation of an individual observer. To improve objective assessment of distress we studied the locomotor activity pattern of mice during a 24-h interval. As a reference compound, Freund's complete adjuvant (FCA) was used. Mice were injected intraperitoneally with different doses FCA (0, 0.1, 0.2 and 0.5 ml) and observed for 5 to 7 days. Animals did not appear to be in pain and seemed to have a normal activity and behaviour pattern at first sight, however FCA induced a dose-dependent decrease of body weight. Open field activity (total distance run) measured during a limited period of time was not altered as a result of FCA. However, nocturnal activity was dose dependently decreased during the first 3 to 4 nights after treatment with FCA. The data presented indicate that using locomotor activity patterns over 24 h might be a useful adjunct and an objective approach to assess distress.

Animals↗

PubMed1985

Automatic detection of spike-and-wave bursts in ambulatory EEG recordings.

The spike-and-wave detection scheme described in this report is based on the recognition of groups of spikes and sharp waves with loosely defined temporal and inter-channel relationships; presence of a slow wave is required only with spikes of low amplitude. Particular attention is paid to artefacts. This method allows the detection of classical 3/sec spike-and-wave activity as well as irregular patterns. The analysis produces a standard EEG tracing containing only the detected bursts, allowing conventional visual examination by an electroencephalographer. After interactive editing of false detections, a quantitative display of burst distribution can be obtained. The rate of false detections due to artefacts or non-epileptiform patterns was evaluated on eight 20 h cassette recordings; an average of 2.4-10 false detections were made per hour. When tested against hand-scoring by two EEGers of eight 2 h recordings which included very irregular spike-and-wave patterns, the computer detected 70% of the spike-and-wave activity identified by both readers (i.e., 30% false negatives), while 12% of the computer detections were not identified by either reader (false positives). The context in which such a computer method with imperfect performance can be clinically useful is discussed.

Adolescent↗

PubMed1985

Unique pattern of HTLV-III (AIDS-related) antigen recognition by sera from African children in Uganda (1972).

Of 75 sera collected in the West Nile district of Uganda over a 1-year period between 1972 and 1973, 50 (66%) had antibody reactivity to human T-cell lymphotropic virus subgroup III (HTLV-III) at low titer levels. Sera were initially screened by HTLV-III enzyme linked immunosorbent assay and sera with values less than normal mean + 2 SD were removed from testing. The remaining sera were tested for positivity by an amplified Western blotting procedure which incorporated a three-layer immunoperoxidase procedure. Immunoglobulin reactive with HTLV-III Mr 24,000, 41,000, and 76,000 proteins were present in nearly all positive sera. The antibody status of this group was unlike any normal or acquired immunodeficiency syndrome-risk group previously tested. The high prevalence and relatively low titers suggest the detection as early as 1972 of a relative or predecessor of HTLV-III or of HTLV-III itself but existing in a population acclimated to its presence. It further suggests a likely African origin of HTLV-III.

Acquired Immunodeficiency Syndrome↗

PubMed2006

Adaptive conditioning of skeletal muscle in a large animal model (Sus domesticus).

Recognition of the adaptive capacity of mammalian skeletal muscle has opened the way to a number of clinical applications. For most of these, the fast, fatigue-susceptible fibres need to be transformed stably to fast, fatigue-resistant fibres that express the 2A myosin heavy chain isoform. The thresholds for activity-induced change are size-dependent, so although the requisite patterns of electrical stimulation are known for the rabbit, in humans these same patterns would produce type 1 fibre characteristics, with an undesirable loss of contractile speed and power. We have used histochemistry, immunohistochemistry and electrophoretic separations to evaluate a possible conditioning regime in a large animal model. Stimulation of the porcine latissimus dorsi muscle with a phasic 30-Hz pattern for up to 41 days converted all type 2X and 2A/2X fibres to 2A with only a small increase in the type 1 population, from 17% to 22%. Stimulation for longer periods increased the proportion of type 1 fibres to 52%. Based on this model, stimulation regimes designed to achieve a stable 2A phenotype in humans should deliver fewer stimulating impulses, possibly by a factor of 2, than the pattern assessed here. Any such pattern needs to be tested for at least 8 weeks.

Adaptation, Physiological↗

PubMed2003

An inverse method for the recovery of tissue parameters from colour images.

The interpretation of colour images is presented as an inverse problem in which a mapping is sought between image colour vectors and the physiological parameters characterizing a tissue. To ensure the necessary one-to-one correspondence between the image colours and the parameters, the mapping must be unique. This can be established through testing the sign of the determinant of the Jacobian matrix, a multi-dimensional equivalent of a discrete derivative, over the space of all parameter values. Furthermore, an optimisation procedure is employed to find the set of filters for image capture which generate image vectors minimizing the mapping error. This methodology applied to interpretation of skin images shows that the standard RGB system of filters provides for a unique mapping between image values and parameters characterizing the normal skin. It is further shown that an optimal set of filters reduces the error of quantification by a factor of 2, on average.

Algorithms↗

PubMed1978

Intermediate coronary care. Observations on the validity of the concept.

Recognition of significant mortality among hospitalized patients with myocardial infarction after dismissal from the coronary care unit (CCU) has led to the introduction of the intermediate coronary care unit (ICCU). It had been hoped that protracted monitoring during the convalescent phase of acute myocardial infarction might prevent sudden death, as in the CCU. Study of patterns of survival among 1,361 patients with acute myocardial infarction included 814 patients treated prior to the establishment of an ICCU and 557 managed in such a unit. Analysis of the two groups (including such high-risk factors as congestive heart failure, tachyarrhythmias, previous infarction, cardiac enlargement, and other unfavorable manifestations) failed to reveal a reduction in mortality after introduction of the ICCU. Thus, the value of the ICCU cannot be demonstrated in terms of mortality. Other benefits of the ICCU are projected, which include more sophisticated evaluation of the patient prior to discharge from the hospital and expanded opportunities for education of patients. A definite role of the ICCU in the total management of the patient with coronary arterial disease is postulated.

Coronary Care Units↗

PubMed2003

Reactive oxygen species generated by microbial NADPH oxidase NoxA regulate sexual development in Aspergillus nidulans.

NADPH oxidases (Nox) have been characterized as higher eukaryotic enzymes used deliberately to produce reactive oxygen species (ROS). The recent discovery of new functional members of the Nox family in plants and animals has led to the recognition of the increasing importance of ROS as signals involved in regulation of diverse cellular processes such as defence, growth and signalling. Here, we address the role of NADPH oxidase-generated ROS in the biology of the filamentous fungus Aspergillus nidulans. We characterize the noxA gene and show that it encodes a member of a novel NADPH oxidase subfamily ubiquitous in lower eukaryotes. Deletion of noxA specifically blocks differentiation of sexual fruit bodies (cleistothecia), without affecting hyphal growth or asexual development. Accordingly, the noxA gene is induced during sexual development, peaking at the time of cleistothecia differentiation and in parallel with the hülle cell-associated catalase peroxidase gene cpeA. This expression pattern is not dependent on transcription factors SteA and StuA, which are essential for cleistothecia formation. In contrast, noxA-dependent premature sexual development correlates with noxA derepression in DeltasakA null mutants, connecting stress MAPK signalling to the regulated production of ROS. Using a nitroblue tetrazolium (NBT) assay to detect superoxide, we found that hülle cells and cleistothecia initials produce superoxide in a process inhibited by NADPH oxidase inhibitor DPI and markedly reduced in DeltanoxA mutants. Furthermore, using H2DCFDA, we detected that H2O2 and possibly other ROS are generated in a NoxA-dependent fashion, mainly in the external walls from cleistothecia initials. The essential role of NoxA-generated ROS in A. nidulans sexual differentiation and the presence of one or two noxA homologues in all analysed filamentous fungi suggest that NADPH oxidase-generated ROS play important roles in fungal physiology and differentiation.

Amino Acid Sequence↗

PubMed1985

Monitoring kidney patients by syntactometric EEG analysis.

The EEG of seriously ill kidney patients reflects changes in their condition which can be measured quantitatively by a syntactic pattern recognition technique. 128 s of an EEG were sampled at 100 Hz and segmented into 4 sec blocks, each of which was labelled D (or d), T (or t), N (or n), S (or s), or B (or b) depending on the position of its main peak in the power spectrum: delta band (0-4 Hz), theta band (4-8 Hz), alpha band (8-12 Hz), sigma band (12-14 Hz) or beta band (over 14 Hz). The use of capital or small letters depends on the size of the peak A refinement of the method also takes into account the second largest peak. The distance of the resulting 32-character 'sentences' from a pattern is calculated using a string-to-string metric based on weighted insertions, deletions and substitutions (insertions and deletions are included to allow for artefacts detected in the signal). Elementary weights have been assigned on empirical medical grounds taking into account the neurological significance of the various spectral bands and their correlation with the levels of creatinine and urea in the bloodstream.

Biomedical Engineering↗

PubMed1997

[Is the immune system our sixth sense? Relation between the immune and neuroendocrine systems].

There is an overwhelming evidence that cytokines, peptide hormones and neurotransmitters, as well as their receptors, are present in the brain, endocrine and immune systems. The structure and pattern of synthesis of these peptides by leukocytes appear similar to those synthesized in the neuroendocrine system, although some differences exist. Once secreted, these peptide hormones may function as endogenous regulators inside of the each system and also in bidirectional communication between the immune and neuroendocrine systems. Such communication suggest an immunoregulatory role for the brain and a sensory function for the immune system which may sense stimuli that are not recognized by the central and peripheral nervous systems (noncognitive stimuli). The plasma hormone concentrations contributed by lymphocytes usually do not reach the levels required when the pituitary gland is the source, but because immune cells are mobile, they have the potential to deposit the hormone locally at the target site. Several immunoregulatory cytokines, including IL-1, IL-2, IL-6, IFN-gama and TNF are produced not only in the immune system but in the neuroendocrine system as well. They have profound effects on neuroendocrine functions especially on hypothalamic pituitary axes. Neuroendocrine influences that modulate the immune function mainly include mental and physical stress. It can reduce the resistance of organism to infectious diseases and malignancies by compromising the immune system directly or indirectly. The brain is not an immunologically privileged site and therefore may become the target of immunologic attacks resulting in neuroimmunological diseases with an autoimmune component. The impact of psychological and psychosocial factors on the immune system is studied by psychoneuroimmunology whereas neuroendocrine immunology is generally interested in the interactions between the immune and neuroendocrine systems under physiological and pathological conditions. The recognition of the identity of ligands and receptors in the immune, nervous, and endocrine systems suggest a radically altered view of the immune systems impact on other tissues and organ systems, and vice versa. This will undoubtedly change our understanding of physiology, and consequently should profoundly impact the practice of medicine. (Tab. 5, Fig. 4, Ref. 85.)

Animals↗