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At least 847 records · Page 47Linked to original sources
PubMed2002

An overview of three different approaches to the interpretation of qualitative data. Part 1: Theoretical issues.

In this paper, the first of two, Helena Priest, Paula Roberts and Leslie Woods discuss the essential features and methods inherent within three approaches to the interpretation of qualitative data. An overview of three methodologies commonly used in nursing and healthcare research is presented: grounded theory, qualitative content analysis and narrative analysis. The paper considers the philosophical bases of the three methods and the principles inherent within each analytical approach. Key stages and steps are presented and described.

Abstracting and Indexing↗
PubMed2004

Validated assays for human cytochrome P450 activities.

The measurement of the effect of new chemical entities on human cytochrome P450 marker activities using in vitro experimentation represents an important experimental approach in drug development. In vitro drug interaction data can be used in guiding the design of clinical drug interaction studies, or, when no effect is observed in vitro, the data can be used in place of an in vivo study to claim that no interaction will occur in vivo. To make such a claim, it must be assured that the in vitro experiments are performed with absolute confidence in the methods used and data obtained. To meet this need, 12 semiautomated assays for human P450 marker substrate activities have been developed and validated using approaches described in the GLP (good laboratory practices) as per the code of U.S. Federal Regulations. The assays that were validated are: phenacetin O-deethylase (CYP1A2), coumarin 7-hydroxylase (CYP2A6), bupropion hydroxylase (CYP2B6), amodiaquine N-deethylase (CYP2C8), diclofenac 4'-hydroxylase and tolbutamide methylhydroxylase (CYP2C9), (S)-mephenytoin 4'-hydroxylase (CYP2C19), dextromethorphan O-demethylase (CYP2D6), chlorzoxazone 6-hydroxylase (CYP2E1), felodipine dehydrogenase, testosterone 6 beta-hydroxylase, and midazolam 1'-hydroxylase (CYP3A4 and CYP3A5). High-pressure liquid chromatography-tandem mass spectrometry, using stable isotope-labeled internal standards, has been applied as the analytical method. This analytical approach, through its high sensitivity and selectivity, has permitted the use of very low incubation concentrations of microsomal protein (0.01-0.2 mg/ml). Analytical assay accuracy and precision values were excellent. Enzyme kinetic and inhibition parameters obtained using these methods demonstrated high precision and were within the range of values previously reported in the scientific literature. These methods should prove useful in the routine assessments of the potential for new drug candidates to elicit pharmacokinetic drug interactions via inhibition of cytochrome P450 activities.

Amodiaquine↗
PubMed2007

The fatty acid profiles in a drop of blood from a fingertip correlate with physiological, dietary and lifestyle parameters in volunteers.

Limited data are available on the fatty acid (FA) composition of circulating lipids and the associations with diet, physiological and pathological conditions, due to the complexity and costs of the analytical process. The aim of our study was to evaluate the FA composition in 108 healthy subjects and to correlate the data with gender, pregnancy, dietary habits, lifestyle, and short-term controlled intake of n-3 FA, using an innovative analytical approach for the collection and processing of blood samples. Ten subjects were also supplemented with n-3 polyunsaturated FA as smoked salmon or capsules for 3 weeks. The resulting blood FA composition was affected by gender, pregnancy, diet and smoking. The data indicate that this new analytical methodology is suitable for assessing associations between circulating FA and various parameters in large population groups, and is applicable to epidemiological studies and in the assessment of the effects of controlled FA supplementation in clinical studies.

Adult↗
PubMed2002

Approaches to the analysis of gene expression using mRNA: a technical overview.

Messenger RNA is the blueprint for all proteins expressed within living systems. Therefore, the study of mRNA expression within normal and diseased tissues is central to our understanding of biological systems. However, blueprints, in themselves, perform no function unless they are used to produce the material for which they code. Spurious results may frequently result from poorly designed or inappropriate studies. This review seeks to highlight both the pitfalls and the promise of various approaches to the analysis of mRNA in different systems and to place these studies in the wider context of research approaches aimed at understanding the function of living systems. The various techniques for the analysis of mRNA are discussed, with particular reference to their potential uses and problems and relevant examples are cited from the literature. It is hoped that this overview of the uses of analytical approaches will allow both the novice researcher and the more experienced scientist to better structure research approaches.

Blotting, Northern↗
PubMed2005

Quantum approach to nucleation times of kinetic Ising ferromagnets.

Low temperature dynamics of Ising ferromagnets under finite magnetic fields are studied in terms of quantum spin representations of stochastic evolution operators. These are constructed for the Glauber dynamic as well as for its modification, introduced by Park [Phys. Rev. Lett. 92, 015701 (2004)]. In both cases the relaxation time after a field quench is evaluated both numerically and analytically using the spectrum gap of the corresponding operators. The numerical work employs standard recursive techniques following a symmetrization of the evolution operator accomplished by a nonunitary spin rotation. The analytical approach uses low temperature limits to identify dominant terms in the eigenvalue problem. It is argued that the relaxation times already provide a measure of actual nucleation lifetimes under finite fields. The approach is applied to square, triangular and honeycomb lattices.

Journal Article↗
PubMed2006

Priority setting for health interventions in Mexico's System of Social Protection in Health.

Explicit priority setting presents Mexico with the opportunity to match the pressure and complexity of an advancing epidemiological transition with evidence-based policies driven by a fundamental concern for how to make the best use of scarce resources to improve population health. The Mexican priority-setting experience describes how standardised analytical approaches to decision making, mainly burden of disease and cost-effectiveness analyses, combine with other criteria--eg, being responsive to the legitimate non-health expectations of patients and ensuring fair financing across households--to design and implement a set of three differentiated health intervention packages. This process is a key element of a wider set of reform components aimed at extending health insurance, especially to the poor. The most relevant policy implications include lessons on the use of available and proven analytical tools to set national health priorities, the usefulness of priority-setting results to guide long-term capacity development, the importance of favouring an institutionalised approach to cost-effectiveness analysis, and the need for local technical capacity strengthening as an essential step to balance health-maximising arguments and other non-health criteria in a transparent and systematic process.

Adolescent↗
PubMed2000

Lymph node dissection in cutaneous melanoma: surgical and oncological implications.

The concept of Sentinel Lymph Node Dissection (SLND) has strongly influenced the surgical approach towards primary melanoma in the last decade. Initiated by the disappointing results of elective lymph node dissection (ELND) in this malignancy, the concept of analyzing the first draining lymph node (Sentinel) of a regional basin was developed as a diagnostic means to avoid unnecessary ELND in case of negative SLNs. According to recent standards detection of the SLN should be performed by a triple approach: injection of 90 nm Technetium and patent blue in the periphery of the primary melanoma, and intraoperative tracing of radioactivity with the aid of a hand-held gamma probe. Histopathological examination of alternating series sections of the whole lymph node appears to be the best analytic approach. Molecular biologic procedures such as tyrosinase RT-PCR are time-consuming to perform and produce contradictory results. SLND for cutaneous melanoma is an interdisciplinary diagnostic approach involving surgery, dermatology, pathology, and nuclear medicine. In spite of a variety of published promising results derived from clinical trials ranging from a few dozens to several hundred included patients the diagnostic and prognostic value of SLND remains to be confirmed by ongoing controlled prospective clinical trials. At this stage, SLND can by no means be considered a therapeutic procedure. These aspects have to be kept in mind when informed consent is obtained from patients as well as in the individual determination of the risk-benefit ratio.

Clinical Trials as Topic↗
PubMed1997

[Physicians and health care: state, market or regulation? A false issue]

A cost crisis in the health care sector has focused discussion on health care services and an assessment of the results of investments in the health sector, underlining the importance of medical doctors as key actors in this area. This article reviews the main analytical approaches to professionalism in the last decade and discusses the most recent paradigmatic shifts. New approaches have emerged for correlating the medical division of labor (contained in specialized fields which are becoming more and more fragmented) with structural and historical changes in the professional market, as well as the collective action developed by these interest groups in their relationship to the state. These approaches, more closely linked to political economy, have made important contributions to this debate, because they allow for a questioning of the kind of ideological polarization contained in health care reform proposals aimed at a withdrawal of the state and the rule of the market (with no analytical justification), in addition to shifting regulation to a position outside the historically mutable dynamics between the state, health care providers, and clients of the health care sector and the public policy arena.

Journal Article↗
PubMedDate not supplied

A modular on-line three-dimensional liquid chromatography-tandem mass spectrometry approach to characterization of organelle proteomes.

In this work we describe the use of a modular multidimensional chromatography-tandem mass spectrometry approach for rapid identification of proteins. In particular we highlight the use of a strong cation exchange cartridge in conjunction with a membrane postconcentration cartridge and nano-HPLC on-line with tandem mass spectrometry to characterize the eosinophil granule organelle proteome. Details are provided of the analytical approach we have developed and we discuss some of the advantages compared with previously reported analyses, as well as providing some specific examples of novel proteins identified.

Amino Acid Sequence↗
PubMed2003

Natural abundance deuterium NMR spectroscopy in polypeptide liquid crystals as a new and incisive means for the enantiodifferentiation of chiral hydrocarbons.

Polymeric chiral liquid-crystalline solvents based on homopolypeptides are of interest with the view to discriminate between enantiomeric pairs of chiral hydrocarbons using proton-decoupled deuterium one- and two-dimensional NMR spectroscopy at natural abundance level. This method offers the major advantage that neither chemical modification nor isotopic labelling of the solutes to be studied is required. Chiral differentiation between optical isomers is observed through a difference in residual deuterium quadrupolar splittings. The spectroscopic separations and the S/N ratio from the spectra are usually large enough to measure the enantiomeric excess with an accuracy varying between 5 to 10 %. This analytical approach is successfully applied to a large collection of chiral, rigid or flexible unsaturated as well as saturated hydrocarbons, including cases of axial chirality, atropoisomerism, and moieties existing as a mixture of enantiomers interconverting by ring inversion. Using the results reported in literature, a systematic comparison with other analytical strategies (NMR, GC, HPLC, VCD) is made and discussed. Also, a tentative proposal to rationalise the various results in terms of chiral differentiation and enantioselective shape recognition is presented. We show that this original tool provides an attractive and incisive alternative to the existing analytical techniques for studying nonfunctionalised chiral materials.

Chromatography, Gas↗
PubMed2006

A pharmacokinetic formalism explicitly integrating the patient drug compliance.

The adherence phenomenon is now well recognized to seriously compromise drug efficacy. In this paper, we analyze the role of compliance through drug intake history as an integral part of the pharmacokinetic process. Being concerned with what is accessible in medical practice, we develop a stochastic approach to model the drug intake behavior that we combine with a conventional pharmacokinetic model in order to investigate the effect of drug intake history on the pharmacokinetic time-course. For this purpose, we explicitly formalize the plasma concentration variations for the most common administration routes. This analytical approach allows to characterize drug concentration variations directly inherited from patient compliance.

Animals↗
PubMed2003

Intention-to-treat approach to data from randomized controlled trials: a sensitivity analysis.

The intention-to-treat (ITT) approach to randomized controlled trials analyzes data on the basis of treatment assignment, not treatment receipt. Alternative approaches make comparisons according to the treatment received at the end of the trial (as-treated analysis) or using only subjects who did not deviate from the assigned treatment (adherers-only analysis). Using a sensitivity analysis on data for a hypothetical trial, we compare these different analytical approaches in the context of two common protocol deviations: loss to follow-up and switching across treatments. In each case, two rates of deviation are considered: 10% and 30%. The analysis shows that biased estimates of effect may occur when deviation is nonrandom, when a large percentage of participants switch treatments or are lost to follow-up, and when the method of estimating missing values accounts inadequately for the process causing loss to follow-up. In general, ITT analysis attenuates between-group effects. Trialists should use sensitivity analyses on their data and should compare the characteristics of participants who do and those who do not deviate from the trial protocol. The ITT approach is not a remedy for unsound design, and imputation of missing values is not a substitute for complete, good quality data.

Data Interpretation, Statistical↗
PubMed2003

The management of affect storms in the psychoanalytic psychotherapy of borderline patients.

Affect storms are a frequent complication in the psychoanalytic approach to borderline patients. The descriptive, psychodynamic, and structural characteristics of these storms are explored, and the verbal, nonverbal, and countertransference manifestations that permit the formulation of interpretations under such conditions are described, as are the interventions required to maintain the treatment frame as a precondition for an analytic approach. The principal theoretical formulations regarding the affect pathology of borderline patients are reviewed and related to a proposed interpretive approach. An apparently opposite development, the utter absence of emotional developments in the sessions, is examined, and its defensive function of avoiding affect storms is explored. Clinical case material illustrates the proposed approach to these storms, and clinical evidence is given to support the approach, which centers on systematic analysis of the primitive internalized object relations of these patients in the transference, the use of countertransference analysis without countertransference communication to the patient, and the repeated restoration of technical neutrality in the service of protecting the treatment frame.

Acute Disease↗
PubMed1995

Misunderstanding meta-analysis.

Although it is increasingly common, meta-analysis is still a relatively new addition to the toolbox of research strategies. Partially because of its newness and partially because its early enthusiasts may have overstated its presumed contributions, a number of common misunderstandings have developed about the meta-analytic approach. These misunderstandings have to do with the way that meta-analysis is conducted and interpreted and its relation to primary research and narrative review. This article aims to highlight these misunderstandings and offer an alternative view of meta-analysis. It is hoped that meta-analytic research of the future will be a partnership with primary research and that meta-analysis will be valued not so much for its definitiveness as for the creative speculations it allows about patterns that appear across studies.

Data Collection↗
PubMed1999

Tracing therapeutic discourse in material culture.

Approaches to language and subjectivity from post-structuralist theory outside psychology and from deconstructive perspectives within counselling and psychotherapy have questioned the way therapeutic relationships are formed in Western culture. Discourse analysis has been developed as a methodological framework to take this questioning further, and to provide detailed readings of therapeutic patterns of meaning. Foucauldian discourse analytic approaches help us to address how we are made into selves that speak, how we experience the self therapeutically. I will elaborate this methodological framework through an analysis of a piece of text--an item of consumer packaging--tracing the contours of therapeutic discourse through a series of 20 methodological steps. Therapeutic discourse draws the reader in as the kind of subject who must feel a relationship at some depth with the (imagined) authors for the text to work. This paper thus illustrates the value of discourse analytic readings of texts, and helps us to reflect upon our commitment to discourses of counselling and psychotherapy as empowering stories and as culturally-specific patterns of subjectivity.

Counseling↗
PubMed2006

Effect of material properties of composite restoration on the strength of the restoration-dentine interface due to polymerization shrinkage, thermal and occlusal loading.

The purpose of this investigation was to adopt an analytical approach to analyse stresses at the restoration-dentine interface caused by polymerization shrinkage, occlusal and thermal loading with the primary focus on evaluating the effect of the material properties of the composite restoration on the strength of the interface. Some essential simplifications were employed to derive an explicit analytical solution. The results confirm previous findings that interfacial stresses due to polymerization shrinkage are increased with the higher modulus of elasticity of the restoration, while Poisson's ratio of the restorative material has a very small influence on these stresses. Occlusal loading resulted in much lower interfacial stresses when compared to shrinkage and thermal loads. The obtained results were in a good agreement with other numerical and clinical studies. From the modelling analysis it was found that the majority of commercially available composite restorative materials are expected to create significant interfacial stresses when subjected to cold temperatures. In addition, it was shown that there is a considerable potential for interfacial stresses to be minimised by an appropriate selection of thermo-mechanical properties of the restorative material especially with the new finding on the negative temperature variation effect.

Adhesiveness↗
PubMed2001

Improving depression care: barriers, solutions, and research needs.

Potential solutions for barriers to improved organization of care of depressive illness were identified. These included (1) aligning efforts to improve depression care with broader strategies for improving care of other chronic conditions; (2) increasing the availability of depression case management services in primary care; (3) developing registries and reminder systems to ensure active follow-up of depressed patients; (4) achieving agreement on how depression outcomes should be measured to provide outcomes-based performance standards; (5) providing greater support from mental health specialists for management of depressed patients by primary care providers; (6) campaigns to reduce the stigma associated with treatment of depressive illness; (7) increased dissemination of interventions that activate and empower patients managing a depressive illness; (8) redefining the lack of time of primary care providers for high-quality depression care as issues in organization of care and provider training; and (9) development of incentives (organizational or financial) for high-quality depression care. Research needs were identified according to what has been learned to date. Identified research needs included: studies of approaches to organization of case management, research in new populations (e.g., new diagnostic groups, rural populations, the disadvantaged, the elderly, and those with chronic medical illnesses), research on stepped care and relapse prevention strategies, evaluation of the societal benefits of improved depression care, and multisite trials and meta-analytic approaches that can provide adequate statistical power to assess societal benefits of improved care.

Case Management↗
PubMed1996

Analysis of workload predictions generated by multiple resource theory.

BACKGROUND: During the design process, operator workload assessments sometimes require subject matter experts (SME's) to predict the amount of physical and mental demands they expect during system employment. Often, these subjective estimates are considered within the context of models that partition human capabilities into discrete resources. Such models require the SME's to rate tasks on how they affect resource consumption. This type of assessment technique is based upon the premise that raters can effectively discriminate their own resources. METHODS: Subjective workload ratings based on multiple resource theory were collected independently from two highly experienced pilots for 225 different tasks of an anticipated mission for a future advanced strike aircraft. The data were examined using a factor analytic approach. RESULTS: Factor analysis of their responses suggest that while such ratings have high face validity and even high inter-rater reliabilities, the ratings could have little validity in terms of efforts required to use the seven postulated resource channels (i.e., visual or auditory input, spatial, verbal or analytical cognition, and manual or speech output). Ratings of efforts required for the cognitive resource channels were particularly suspect. We identified four independent factors for each pilot that accounted for virtually all of the intercorrelations among the 7 resource channels. Three factors (i.e., visual-spatial, verbal communications, and manual and speech output) were identical for both pilots and accounted for most of the explainable variance. CONCLUSION: Given these results, this analysis challenges the utility of a multiple resource framework for predictive workload assessments.

Adult↗