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Results for “New approach methodologies”

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At least 91 records · Page 5Linked to original sources

PubMed2006

Sources of cortical rhythms in adults during physiological aging: a multicentric EEG study.

This electroencephalographic (EEG) study tested whether cortical EEG rhythms (especially delta and alpha) show a progressive increasing or decreasing trend across physiological aging. To this aim, we analyzed the type of correlation (linear and nonlinear) between cortical EEG rhythms and age. Resting eyes-closed EEG data were recorded in 108 young (Nyoung; age range: 18-50 years, mean age 27.3+/-7.3 SD) and 107 elderly (Nold; age range: 51-85 years, mean age 67.3+/-9.2 SD) subjects. The EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Statistical results showed that delta sources in the occipital area had significantly less magnitude in Nold compared to Nyoung subjects. Similarly, alpha 1 and alpha 2 sources in the parietal, occipital, temporal, and limbic areas had significantly less magnitude in Nold compared to Nyoung subjects. These nine EEG sources were given as input for evaluating the type (linear, exponential, logarithmic, and power) of correlation with age. When subjects were considered as a single group there was a significant linear correlation of age with the magnitude of delta sources in the occipital area and of alpha 1 sources in occipital and limbic areas. The same was true for alpha 2 sources in the parietal, occipital, temporal, and limbic areas. In general, the EEG sources showing significant linear correlation with age also supported a nonlinear correlation with age. These results suggest that the occipital delta and posterior cortical alpha rhythms decrease in magnitude during physiological aging with both linear and nonlinear trends. In conclusion, this new methodological approach holds promise for the prediction of dementia in mild cognitive impairment by regional source rather than surface EEG data and by both linear and nonlinear predictors.

Adolescent↗

PubMed2002

Appraisal of SIMS applicability to boron studies in plants.

In the search for a new methodological approach applicable to the determination of the still poorly known primary role of boron in plant physiology, we have undertaken to appraise the potential of the SIMS method for the analytical imaging of the boron isotopes, (10)B and (11)B, at physiological concentrations in plants. With our own, CAMECA IMS4F SIMS ion analyser, and using O(2)(+) as primary ions for the detection of B(+) (plus (12)C(+) and (40)Ca(+)) secondary ions, we have been able to map quantitatively the two boron isotopes in control and boron-enriched plants, to evaluate boron concentrations at the level of individual cells and to determine boron isotopic ratios. This provides the opportunity to carry out the simultaneous labeling and imaging of boron, using enrichment with the stable isotopes, (10)B and (11)B. The method has also the potential for the simultaneous, quantitative detection of the boron isotopes and of the borate-binding sites in plant cells.

Boron↗

PubMedDate not supplied

Red cell membrane protein phosphorylation in hemolytic anemias and muscular dystrophies.

We review our current understanding of membrane phosphorylation in normal and abnormal erythrocytes. The major phosphoproteins in red blood cell (RBC) membranes are spectrin (band 2), bands 3, 2.1, and 4.5, and glycophorin A. At least two protein kinases can be distinguished on the basis of their stimulation by cyclic AMP and salt; they are present both in the membrane and in the cytosol. Analysis of the conflicting data on endogenous membrane-protein phosphorylation in abnormal RBCs indicates a considerable variability of phosphorylation rates which largely depends on the manner of preparation of ghosts and enzyme assay conditions. This variability reflects differences in the partitioning of protein kinases between the membrane and cytosol, the specificity and accessibility of membrane-protein substrates, and reaction kinetics. We select examples of data from several hemolytic anemias to illustrate that precautions are needed to interpret abnormalities of membrane-protein phosphorylation properly; we discuss possible new methodological approaches.

Actins↗

PubMedDate not supplied

Patch-clamp capacitance measurements: new insights into the endocytic uptake of transferrin.

Since its introduction by Neher and Sakmann in 1976 the patch-clamp technique has been extensively used to study processes such as signalling and synaptic transmission, but also for monitoring endo- and exocytosis. Since biological membranes behave like electrical capacitors high-resolution measurements of membrane capacitance allow detection of small changes in membrane surface area that accompany exocytosis and endocytosis. We here describe our recent work on patch-clamp capacitance measurements in stably transfected HeLa cells expressing HFE, the hereditary hemochromatosis gene product, under the control of a tetracycline-sensitive promotor. By means of whole-cell and cell-attached techniques we were able to reveal transferrin-induced decreases in membrane capacitance reflecting increased endocytosis at the single cell level. Moreover, cell-attached recordings revealed significant alterations in the formation of single endocytic vesicles. Time-resolved measurements of cell membrane capacitance provide a new methodological approach to study the endocytic uptake of transferrin and its regulation by HFE, the hereditary hemochromatosis protein.

Cytoplasmic Vesicles↗

PubMed1989

Plasma moclobemide and metabolites: lack of correlation with clinical response and biogenic amines.

The concentration of the reversible monoamine oxidase type-A (MAO-A) inhibitor moclobemide (Ro 11-1163) was determined by high pressure liquid chromatography (HPLC) in the plasma of 16 depressives treated with moclobemide. Moreover, the inhibitory potency of organic extracts of the plasma on a standard MAO-A preparation from human placenta was measured spectrophotometrically. The inhibitory potency significantly correlated with the HPLC results. However, it overestimated the concentration of moclobemide by one order of magnitude possibly due to the presence of yet unknown metabolites more active than moclobemide itself. These have already been suggested in view of the higher inhibitory potency of moclobemide ex vivo than in vitro. This new methodological approach might represent a comfortable alternative to HPLC procedures in pharmacokinetic studies on reversible MAO inhibitors. Plasma biogenic amines and their metabolites might be indicative of the biologic activity of moclobemide. Plasma homovanillic acid (HVA) decreased and norepinephrine (NE) increased under moclobemide, although insignificantly. There was no significant correlation between the plasma concentration of moclobemide as estimated by either method and the therapeutic response and the change of plasma HVA and NE.

Adult↗

PubMed1992

Viscoelastic response of human hair cortex.

The present study describes a new methodological approach which allows the separate analysis and quantitative determination of the viscous and elastic components of human hair using a computerised experimental system. In a first series of experiments subsequent to the estimation of the cross-sectional surface area of the cuticle, the cortex and the medulla, the viscoelastic response of hair (considered as a homogeneous material) and of its cortex were determined in ten hair specimens derived from the same human subject. Statistically significant differences were found between hair and its cortex with regard to the values of the modulus of elasticity, limit of linearity and post-yield slope. In a second series of experiments the viscoelastic parameters of hair and its cortex were separately determined in 100 hair specimens derived from ten healthy human subjects (ten specimens from each subject). It was found that the dispersion of the values of modulus of elasticity, limit of linearity and post-yield slope of the cortex was significantly reduced compared with that of the hair. Our results indicate that the pattern of the viscoelastic parameters of human hair cortex, which strongly depends on its microstructural features, may be regarded as a more reliable and sensitive diagnostic marker than that of hair in various structural and functional hair disorders.

Biomechanical Phenomena↗

PubMedDate not supplied

Beyond discipline: creating a culture for interdisciplinary research.

Interdisciplinary research is not a common research paradigm. To venture from their customary disciplinary tenets and methods and risk new methodological approaches, or to compromise in order to accommodate the differences in the way disciplines approach research, requires the commitment of investigators. This paper discusses the interdisciplinary research paradigm, its culture, and how it differs from traditional research methods, and provides examples of successful and unsuccessful interdisciplinary research projects.

Models, Organizational↗

PubMed2005

[One decade of functional imaging in schizophrenia research. From visualisation of basic information processing steps to molecular-genetic oriented imaging].

Modern neuroimaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET) have contributed tremendously to our current understanding of psychiatric disorders in the context of functional, biochemical and microstructural alterations of the brain. Since the mid-nineties, functional MRI has provided major insights into the neurobiological correlates of signs and symptoms in schizophrenia. The current paper reviews important fMRI studies of the past decade in the domains of motor, visual, auditory, attentional and working memory function. Special emphasis is given to new methodological approaches, such as the visualisation of medication effects and the functional characterisation of risk genes.

Biomarkers↗

PubMed2002

Subjective well-being and quality of life under atypical antipsychotic treatment.

The increasing interest in subjective well-being and quality of life of schizophrenic patients represents a conceptual shift in therapeutic outcome criteria. Symptom reduction alone was the most essential outcome parameter for a long time; with the development of atypical antipsychotics more ambitious success criteria, including the patients' perspective, are considered today. While effects on (positive) psychopathology do not differ markedly between typical and atypical antipsychotics, the lack of motor symptoms, the improvement of negative, affective and cognitive symptoms, and particularly the better subjective well-being as well as quality of life are major advantages for the new antipsychotic drugs. Quality of life assessment is a new methodological approach to differentiate therapeutic effects and to give more consideration to the patient's perspective. A number of disease-specific or generic scales have been used to measure quality of life of schizophrenic patients under neuroleptic treatment. There is strong evidence by seven controlled and eight open trials that in comparison to typical neuroleptics, atypicals increase the quality of life significantly, and the difference is of major clinical relevance in many patients. This review describes the development of quality of life research in schizophrenic patients, and summarises the methodological problems and the numerous clinical trials. Furthermore, the benefit of introducing atypical antipsychotics early in the course of illness and their particular benefit in combination with rehabilitative non-pharmacological treatment is discussed.

Antipsychotic Agents↗

PubMed2001

Direct mass-quantification of particulate deposits of polycyclic aromatic hydrocarbons by Fourier transform imaging microscopy.

Successful coupling of imaging microscopy with Fourier transform spectrometry provides a new methodological approach. This was applied to the direct analysis of particulate deposits of polycyclic aromatic hydrocarbons (PAHs). The fluorescence signals of single microscopic particulates were found to be proportional to their mass, obtained from the corresponding HPLC results. Special fluorescence characteristics related to individual particle analysis were studied. The sensitivity of the proposed method to PAHs in soil is in the sub-ppb range, similar to HPLC results. Analysis of inhomogeneous PAH-particulates was demonstrated, as well as the resolution of photochemical products of PAHs. The effects of particulate orientation relative to the detector upon quantification are discussed.

Chromatography, High Pressure Liquid↗

PubMed1997

[Calibration of clinical databanks with "virtual patients"].

The scientific value of multicenter studies is still questionable, as there are no methods available that allow to determine whether in fact identical items are recorded in the same way in different centers. Subjective classifications (for example according to the New York Heart Association (NYHA)), definitions of items, documentation habits and procedures may not be comparable in different hospitals. For that reason the concept of a "virtual patient" for calibration of database systems was developed as a new methodological approach. The "virtual patients" describes a computer program that includes and uses multimedia-tools to represent an exactly defined patient. A sound card enables a patient to talk and to represent intracardial and intrapulmonary sounds. Additional information including echocardiographic sequences, perioperative video sequences, x-ray analysis, angiograms, etc. is represented in the program. Thus during the perioperative course of a patient the complete relevant pre-, intra- and postoperative information regarding the patient is provided. Any physician participating in a multicenter study is asked to record the data of this virtual patient and to store it in a database system using the sheets applied in a multicenter study. As the patient is exactly defined (virtual patient) incorrect classifications and incomplete recordings, etc. can easily be detected and discussed. The virtual patient is a tool that allows calibration of database systems by direct comparison of the documentation technique between different physicians and different hospitals participating in multicenter studies. It is thus a multimedia-instrument to support standardization and quality assurance of database systems.

Calibration↗

PubMed1982

Mapping remodeling reversals with the aid of the scanning electron microscope.

The histologic research on craniofacial remodeling is briefly summarized. A new methodologic approach using the scanning electron microscope (SEM) and high-resolution replicas of craniofacial bone is evaluated. Two maxillae were chosen for illustrative purposes. The specimens were replicated and prepared for routine SEM examination. In addition, a grid was applied to the replicas so that the bone growth activity states could be mapped on a coordinate system. The topographic ("T") principle is introduced as a precedent for discriminating remodeling bone growth activity states with the SEM. These activity states in vivo specify characteristic microscopic surface topographies. The three distinctive surfaces are resorptive, depository, and resting, which are mapped on a coordinate system. Results obtained are similar to those of histologic studies. The primary advantage of the SEM/replica technique is that it does not damage the specimen. This feature will facilitate more extensive investigations of craniofacial remodeling. The time and financial investments for the SEM/replica technique are significantly less than the histologic technique in the investigation of similar material. The SEM/replica technique, however, cannot be used to study nonexternal surfaces and evidence of remodeling contained within the bone cortex.

Bone Resorption↗

PubMed1988

Proteolytic activity in electropherograms (SDS-PAGE) of bovine erythrocyte ghosts.

1. Activity of proteases, strongly related with erythrocyte membrane, was analysed employing a new methodological approach. 2. Intact bovine ghosts, ghosts depleted in peripheric proteins or purified Triton X-100 and ghost extracts were electrophoresed and the proteolytic activity in the gel fragments (SDS-PAGE) was assayed. 3. At least two proteases that were inhibited by EDTA and PMSF were found.

Animals↗

PubMed1996

A telemedicine system for remote cooperative medical imaging diagnosis.

Telemedicine is changing the classical form of health care delivery, by providing efficient solutions to an increasing number of new situations: here we consider those which require some type of computer-supported cooperative work (CSCW) between health care professionals located in different clinical sites. This paper presents the design and development of a telemedicine system for remote computer-supported cooperative medical imaging diagnosis. The main and novel component of our system is a new CSCW distributed architecture, comprised by a collaborative toolkit to add audioconferencing, telepointing, window sharing, user's coordination and application synchronization facilities, either to existing or new medical imaging diagnosis applications. In comparison with existing CSCW products, mainly based on centralized architectures, our distributed toolkit is specially designed for telemedicine applications: to allow different levels of sharing between participants, to improve user feedback in highly interactive user interfaces, and to optimize the required communication bandwidth in order to implement a telemedicine CSCW application on almost any telecommunication network. This telemedicine CSCW system has been applied to build a cooperative medical imaging diagnosis application, in which two doctors, located in different hospitals, need to achieve a cooperative diagnosis on haemodynamic studies using cardiac angiography images. The design of the graphical user interface for this kind of telemedicine CSCW systems, a critical component which conforms any telemedicine application, is also addressed with a new methodological approach, to assure the system usability and final user acceptance. The telemedicine cardiac angiography pilot has been implemented, tested and evaluated within the Research Project 'FEST-Framework for European Services in Telemedicine' funded by EU AIM Programme.

Attitude to Computers↗

PubMed2004

A statistical method for the quantification of the learning index by means of multiple answer tests-Graduated Response Test.

In the fields of didactics and continuous professional development (CPD) plans, the increasing use of multiple answer tests for the evaluation of the level of knowledge in various kinds of subjects makes it increasingly important to have reliable and effective tools for data processing and for the evaluation of the results. The aim of the present work is to explore a new methodological approach based on a widely tested statistical analysis able to yield more information content when compared with the traditional methods. With this purpose we suggest a Graduated Response Test and the relative operating characteristic curve (ROC) for the evaluation of the results. A short description of a computerized procedure, written in Visual Basic Pro (v.6.0), which automatically performs the statistical analysis, the ROC curves plot and the calculation of a learning index is given as well.

Computer-Assisted Instruction↗

PubMed2006

Dental microwear texture analysis: technical considerations.

Dental microwear analysis is commonly used to infer aspects of diet in extinct primates. Conventional methods of microwear analysis have usually been limited to two-dimensional imaging studies using a scanning electron microscope and the identification of apparent individual features. These methods have proved time-consuming and prone to subjectivity and observer error. Here we describe a new methodological approach to microwear: dental microwear texture analysis, based on three-dimensional surface measurements taken using white-light confocal microscopy and scale-sensitive fractal analysis. Surface parameters for complexity, scale of maximum complexity, anisotropy, heterogeneity, and textural fill volume offer repeatable, quantitative characterizations of three-dimensional surfaces, free of observer measurement error. Some results are presented to illustrate how these parameters distinguish extant primates with different diets. In this case, microwear surfaces of Cebus apella and Lophocebus albigena, which consume some harder food items, have higher average values for complexity than do folivores or soft fruit eaters.

Alouattinae↗

PubMed2002

Impact of roadside features on the frequency and severity of run-off-roadway accidents: an empirical analysis.

In the US, single-vehicle run-off-roadway accidents result in a million highway crashes with roadside features every year and account for approximately one third of all highway fatalities. Despite the number and severity of run-off-roadway accidents, quantification of the effect of possible countermeasures has been surprisingly limited due to the absence of data (particularly data on roadside features) needed to rigorously analyze factors affecting the frequency and severity of run-off-roadway accidents. This study provides some initial insight into this important problem by combining a number of databases, including a detailed database on roadside features, to analyze run-off-roadway accidents on a 96.6-km section of highway in Washington State. Using zero-inflated count models and nested logit models, statistical models of accident frequency and severity are estimated and the findings isolate a wide range of factors that significantly influence the frequency and severity of run-off-roadway accidents. The marginal effects of these factors are computed to provide an indication on the effectiveness of potential countermeasures. The findings show significant promise in applying new methodological approaches to run-off-roadway accident analysis.

Accidents, Traffic↗

PubMed2001

Recent advances in human gene-longevity association studies.

This paper reviews the recent literature on genes and longevity. The influence of genes on human life span has been confirmed in studies of life span correlation between related individuals based on family and twin data. Results from major twin studies indicate that approximately 25% of the variation in life span is genetically determined. Taking advantage of recent developments in molecular biology, researchers are now searching for candidate genes that might have an influence on life span. The data on unrelated individuals emerging from an ever-increasing number of centenarian studies makes this possible. This paper summarizes the rich literature dealing with the various aspects of the influence of genes on individual survival. Common phenomena affecting the development of disease and longevity are discussed. The major methodological difficulty one is confronted with when studying the epidemiology of longevity involves the complexity of the phenomenon, which arises from the polygenic nature of life span and historical mortality change. We discuss this issue and suggest new methodological approaches.

Humans↗