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PubMed2002

New methodology for assessment of intimal hyperplasia of vascular prostheses.

BACKGROUND: When investigating the degree of formation of intimal hyperplasia (IH) quantification of the extent of the lesion is crucial to its assessment and analysis. The aim of the present study was to establish a new methodology (IH index) for estimating the degree of IH associated with vascular prosthesis implantation. METHODS: Ten female Merino sheep underwent a standard gelatin sealed Dacron (GSD) patch grafting procedure in the left common carotid artery. The grafts were harvested 4 weeks following implantation and processed for assessment of IH by two methodologies - mean intimal thickness (MIT) and IH index. The advantages and disadvantages of the two methods for expressing the degree of IH were compared. RESULTS: The IH index is less labour intensive but is as accurate as the MIT method in quantifying the IH lesion, statistical analysis showing high correlation and measurement agreement between the two methods. CONCLUSION: The IH index is a labour saving standardized methodology for quantification of IH in the current animal model.

Animals↗

PubMed2003

Methodologic issues in the use of bleeding as an outcome in transfusion medicine studies.

BACKGROUND: Prophylactic platelet transfusions are given to thrombocytopenic patients to prevent bleeding. The benefit of platelet transfusions has frequently been assessed by measuring the count increment; however, more recently, an assessment of bleeding has been used because it is a more clinically relevant outcome measure. The purpose of this study was to identify platelet transfusion trigger studies that used bleeding as an outcome measure, compare and contrast methods used to document bleeding and analyze bleeding outcomes, and identify and discuss methodologic issues to consider when bleeding is used as a study outcome. STUDY DESIGN AND METHODS: A systematic search to identify platelet transfusion trigger studies was performed. Relevant articles were reviewed to identify how bleeding data was captured and analyzed, and methodologic considerations were identified. RESULTS: Seven articles meeting the predefined entry criteria were identified. Methods used to document bleeding included chart review and clinical assessment. The frequency of assessment and the type of personnel performing the assessment were variable. Four approaches to analysis were identified: descriptive; comparison of the proportions of patients having at least one bleed; comparison of patient days with bleeding expressed as a proportion of the total days at risk of bleeding; and time-to-event (first bleed) analysis. CONCLUSION: Methodologic issues for consideration when designing a clinical study with bleeding as the outcome measure included approaches to minimize bias in the documentation and classification of bleeding and selection of an analysis approach that is appropriate to the question being asked. The need for development of a valid and reliable bleeding scale was also identified.

Data Collection↗

PubMed2000

Clinical tests of the sacroiliac joint. A systematic methodological review. Part 1: Reliability.

In the literature concerning the sacroiliac joint (SIJ) there are numerous specific tests used to detect joint mobility or pain provocation. In this article the authors have reviewed 11 studies which investigated the reliability of these tests. The methodological quality of the studies was tested by a list of criteria developed by the authors. This list consisted of three categories: (1) study population, (2) test procedures and (3) test results. To each criterion a weighting was attached. The methodological score for nine out of the 11 studies was found to be acceptable. The results of this review, however, could not demonstrate reliable outcomes and therefore no evidence on which to base acceptance of mobility tests of the SIJ into daily clinical practice. There are no indications that 'upgrading' of methodological quality would have improved the final conclusions. With respect to pain provocation tests, the findings did not show the same trend. Two studies demonstrated reliable results using the Gaenslen test and the Thigh thrust test. One study showed acceptable reliability for five other pain provocation tests; however, since other authors have described contradictory results, there is a necessity for further research in this area with an emphasis on multiple test scores and pain provocation tests of the SIJ.

Humans↗

PubMed1999

Protein synthesis by native chemical ligation: expanded scope by using straightforward methodology.

The total chemical synthesis of proteins has great potential for increasing our understanding of the molecular basis of protein function. The introduction of native chemical ligation techniques to join unprotected peptides next to a cysteine residue has greatly facilitated the synthesis of proteins of moderate size. Here, we describe a straightforward methodology that has enabled us to rapidly analyze the compatibility of the native chemical ligation strategy for X-Cys ligation sites, where X is any of the 20 naturally occurring amino acids. The simplified methodology avoids the necessity of specific amino acid thioester linkers or alkylation of C-terminal thioacid peptides. Experiments using matrix-assisted laser-desorption ionization MS analysis of combinatorial ligations of LYRAX-C-terminal thioester peptides to the peptide CRANK show that all 20 amino acids are suitable for ligation, with Val, Ile, and Pro representing less favorable choices because of slow ligation rates. To illustrate the method's utility, two 124-aa proteins were manually synthesized by using a three-step, four-piece ligation to yield a fully active human secretory phospholipase A(2) and a catalytically inactive analog. The combination of flexibility in design with general access because of simplified methodology broadens the applicability and versatility of chemical protein synthesis.

Amino Acid Sequence↗

PubMed2002

Effect of the methodology on circulating peptides determination and consequences on net flux measurements across the gastrointestinal tract of sheep.

Two methodologies for the measurement of peptide amino acids (PAA) in blood were compared to evaluate their effects on the measurement of the net flux of peptides across the gastrointestinal tract of sheep. These methods consisted of a chemical deproteinization of blood samples with sulfosalicylic acid (1.6 M, 0.1 ml for 1 ml of sample) or perchloric acid (1 M, 1 ml for 1 ml of sample) followed by ultrafiltration through a 3,000-Da cut-off filter (SSA + UF3 kD) or gel filtration through a Sephadex G-15 column (1,500-Da cut-off filter; PCA + G-15), respectively, prior to PAA analysis. Peptide concentrations as determined by amino acid concentrations before and after hydrolysis of samples were slightly greater with the SSA + UF3 kD (991 microM) than with the PCA + G-15 (605 microM) methodology. However, both methodologies gave similar net portal-drained viscera flux data in sheep fed on alfalfa pellets with histidine as the only significant uptake of peptide amino acid.

Amino Acids↗

PubMed2005

A new methodology for teaching clinical reasoning skills: problem solving clinical seminars.

In the final year of the medical curriculum of the Faculty of Medicine of the Katholieke Universiteit Leuven (Belgium), a new methodology for teaching clinical skills was introduced: Problem Solving Clinical Seminars (PSCS). Two eight-week series of 70 seminars were offered. Students prepared for the seminars in groups of five students who worked on one or more clinical cases followed by half-open questions. Additional information was collected individually. At the clinical seminar the solutions were presented and discussed, guided by a clinical teacher. A questionnaire was administered to investigate whether students perceive the new type of clinical seminars as a powerful learning environment. Students were satisfied with the new methodology. The importance of the postulated educational aspects--preparation, clinical case and the seminar--was confirmed. The preparation phase (self-study and group work) and the clinical seminar were experienced as two separate and important learning events. The implementation of the problem solving clinical seminars is considered by students to be a powerful learning environment and therefore a broader applicability of the PSCS methodology is recommended.

Belgium↗

PubMed1998

Methodology of a two-step quantified nutritional questionnaire and its effect on results.

The effects of methodology on the results of epidemiologic studies that involve collection of nutritional data, especially those involving long-term-onset illnesses such as cancer, have not yet been carefully evaluated. We present methodological features of a quantitative dietary history and physical activity questionnaire and discuss their contribution to the final results. The results of our analysis are as follows: 1) Forty-seven percent of the population consumed > 100 food items yearly. 2) The mean number of calories contributed by items eaten less than once a week exceeded 200 kcal/day in 50% of interviewees. 3) Seventy-six percent of the patients had undergone dietary changes during the course of adult life. Of the 379 individuals who reported no changes when asked general questions, 61.8% reported changes when asked specifically about each food item in the questionnaire. 4) Physical activity was significantly correlated with mean daily energy intake (r = 0.208, p < 0.001). We conclude that certain methodological features of questionnaires, such as extensive listing of food items, precise documentation of food quantity, inquiries about former eating habits, and inclusion of questions about physical activity, increase accuracy in evaluations of dietary habits. Our analysis provides practical information for future planning of nutritional questionnaires.

Adult↗

PubMed2026

Assessment of Methodological Bias in Studies Reporting Racial Differences in Retinopathy of Prematurity in the United States.

PURPOSE: To assess methodological biases in studies reporting racial and ethnic differences in retinopathy of prematurity (ROP). METHODS: Systematic review of peer-reviewed studies published between 2014 and 2024 that reported on ROP outcome measures by race, ethnicity, or social determinants of health (SDOH). Three reviewers independently assessed each observation for selection and collider bias using definitions derived from perinatal epidemiology literature. Findings were also compared using a structured comparative synthesis between studies with and without identified methodological bias. RESULTS: A structured PubMed search identified 78 articles; 13 met inclusion criteria, with one study contributing two distinct analytical approaches, yielding 14 total observations. Survivorship bias was identified in 6 of 14 observations (42.9%), primarily due to the exclusion of infants who died prior to ROP screening. Potential collider bias was most common, found in 9 of 14 observations (64.3%), and was introduced through adjustment or stratification by gestational age and/or birthweight. Three studies did not exhibit either assessed biases. Among studies with identified bias, 8 of 10 observations reported lower ROP risk among Black versus White infants, whereas 3 of 4 observations without identified bias reported higher ROP risk or incidence among Black infants. CONCLUSION: Methodological biases in ROP studies investigating race or ethnicity are prevalent. Adjustment for gestational age or birthweight may introduce spurious race-ROP associations and contribute to paradoxical findings. Further exploration of the impact of SDOH on disease outcomes may reduce the misattribution of race as a biological risk factor and improve the interpretation of ROP disparities.

Collider bias↗

PubMedDate not supplied

The appropriateness and use of focus group methodology across international mental health communities.

The ability to interpret collected data across international mental health communities often proves to be difficult. The following paper reports on the use and appropriateness of focus group methodology in helping to clarify issues that could help substantiate data collection and comparison across different cultures and regions. Field tests of the focus group methodology were undertaken in different regions and this paper describes an overview of the final field test in Sofia, Bulgaria. The findings and experiences with utilizing this methodology were incorporated in subsequent data collections.

Attitude to Health↗

PubMedDate not supplied

Use of hydrophobic moment plot methodology to aid the identification of oblique orientated alpha-helices.

A number of alpha-helix forming peptides have been reported which appear to promote membrane fusion and other biological events related to the disruption of a hydrophobic/hydrophilic interface, due to the presence of a hydrophobicity gradient along the helical long axis. When alpha-helices from this class were analysed according to hydrophobic moment plot methodology a linear association was found to exist between the mean hydrophobic moment, , and the corresponding mean hydrophobicity, . This association was described by the least squares regression line: =0.508-0.422 and, here, a methodology to aid the prediction of oblique orientated alpha-helices is presented, based on a 99% prediction band around this regression line. This methodology is intended to provide an initial identification of candidates for further investigation by other techniques such as the molecular hydrophobic potential and laboratory based experimentation, not to assign function.

Amino Acid Sequence↗

PubMed2006

Estimation of the muscle force distribution in ballistic motion based on a multibody methodology.

This work presents a general three-dimensional multibody procedure for studying the human body motion with emphasis on the locomotion apparatus. The methodology includes a three-dimensional biomechanical model, data acquisition techniques and an inverse dynamics approach. The biomechanical model is based on a multibody formulation using natural coordinates and consists of 16 anatomical segments modeled by 33 rigid bodies for a total of 44 degrees-of-freedom. The action of the muscles is introduced in the equations of motion of the multibody model by means of driver actuators defined as kinematic constraints. By associating a Lagrange multiplier to each muscle actuator the muscle forces became coupled with the biomechanical model through the Jacobian matrix of the underlying multibody system. A Hill type muscle model is used to calculate individual muscle forces. The model for the muscle apparatus comprises 43 muscle groups for each leg, which use the full three-dimensional lines of action for these muscles in their geometric description. The problem of the redundancy of the forces on the musculoskeletal structure is solved by using inverse dynamics and static optimization methods. In the process of describing the methodology the benefits of modeling in natural coordinates are highlighted. The methodology developed is demonstrated through its application to a case of ballistic motion, represented by the take-off to an aerial trajectory in order to estimate the joint torques and the muscle force distribution in the supporting leg. The time characteristics of the resultant net torques at the basic joints of the supporting leg and the time-varying muscle force patterns are presented and discussed. The results obtained are explained in terms of their relevance to the activity under study.

Computer Simulation↗

PubMed1997

Continuous Safety Sampling Methodology.

This research introduces a proactive methodology for accident prevention, called Continuous Safety Sampling Methodology, by utilizing the principles of work sampling and control charting. Sampling is performed to observe the occurrence of conditions that may become hazardous in a given system. These conditions, known as dendritics, may become hazards and could result in an accident or occupational disease. Continuous Safety Sampling Methodology performs a random sampling for the occurrence of these dendritics. The collected data are then used to generate a control chart. Based on the pattern of the control chart, a system "under control" is not disturbed whereas a system "out of control" is investigated for potential conditions becoming hazardous. Appropriate steps are then taken to eliminate or control these conditions to maintain a desired safe system.

accident prediction,↗

PubMed2002

Methodological issues in measuring treatment outcome in adolescent smoking cessation studies.

As the prevalence of adolescent smoking and, notably, regular smoking has increased over the last decade, researchers and practitioners have called for a consideration of treatment programs to promote cessation among adolescents who smoke. The adolescent smoking cessation treatment field is still in its infancy, though. The literature addressing adolescent cessation is rather limited to date, often plagued by methodological problems and characterized by little success. Many basic methodological questions remain for researchers to address before we will be able to answer questions such as which treatment approaches work best for which adolescent smokers. The purpose of this paper is to review briefly what is known about adolescent smoking cessation, to identify some important methodological issues to consider in treatment outcome studies, and to make recommendations to researchers to help provide a common ground for future comparisons of results across studies. We will address the natural history of adolescent smoking cessation, treatment outcomes, validity of self-reports and biochemical validation, and research recommendations.

Adolescent↗

PubMed2003

Evaluation methodology for a medical e-education patient-oriented information system.

This paper describes an evaluation methodology designed for the IMSA (Interactive Multimedia System for Auto-medication) system. IMSA stands in the multidisciplinary field of medical informatics and aims at providing a health care Internet tool for the general public. As far as a medical information system is patient-oriented, issues in understanding content and of human - computer interface usability are key factors to achieve success. The team developing IMSA concentrated part of its work on designing an evaluation methodology to ensure that the system is user-friendly and responds in a way that can be easily understood by the general public. This methodology is built on a three-tier architecture with the user, the evaluator and a set of medical case descriptions. The testing protocol is based on a user trying to run scenarios related to mild clinical signs on the IMSA prototype under the passive presence of an evaluator.

Evaluation Studies as Topic↗

PubMed2005

Bridging the gap: using triangulation methodology to estimate minimal clinically important differences (MCIDs).

This paper proposes the use of triangulation methodology to derive guidelines for interpreting change scores on health outcome measures. Triangulation integrates results from global ratings with clinical benchmarks of change, statistical estimates of magnitude, and qualitative data from patients and/or clinicians to derive guidelines that are not field-specific or method bound. A case study is presented to illustrate how this methodology can be applied. Secondary analyses were performed on blinded data from 2,971 patients enrolled in three phase IlIa clinical trials to develop guidelines for interpreting change scores on the Breathlessness Diary (BD), a relatively new approach for evaluating dyspnea outcomes in patients with chronic obstructive pulmonary disease. BD scores were examined by disease severity and rescue medication use. In addition, mean BD change scores by physician global ratings of efficacy were juxtaposed with changes in forced expiratory volume (FEV1) and St. George's Respiratory Questionnaire scores. Percent change, effect size, one-half standard deviation, and the standard error of measurement were used as statistical indicators of magnitude. Data from qualitative interviews provided insight into patient perspectives of change in dyspnea. Taking into consideration results across estimation methods, guidelines were developed for defining large, moderate, and small group-level mean changes on the BD. Areas of divergence and convergence across statistical indicators and clinical benchmarks in this case study highlight the importance of using triangulation methodology to derive guidelines that are both empirically sound and clinically relevant.

Adult↗

PubMed2001

Methodological principles of case-control studies that analyzed risk factors for antibiotic resistance: a systematic review.

Case-control studies that analyze the risk factors for antibiotic-resistant organisms have varied epidemiological methodologies, which may lead to biased estimates of antibiotic risk factors. A systematic review of case-control studies that analyzed risk factors for antibiotic-resistant organisms addressed 3 methodological principles: method of control group selection, adjustment for time at risk, and adjustment for comorbid illness. A total of 406 abstracts were reviewed. Thirty-seven studies met the inclusion and exclusion criteria and were reviewed and evaluated for the 3 methodological principles. Thirteen (35%) of 37 studies chose the preferred control group. Eleven adjusted for time at risk. Twenty-seven adjusted for comorbid illness. Future studies need to consider more closely the optimization of control group selection, adjusting for confounding caused by time at risk, and adjusting for confounding caused by comorbid illness.

Case-Control Studies↗

PubMed2004

Methodology to predict a maximum follow-up period for breast cancer patients without significantly reducing the chance of detecting a local recurrence.

For breast cancer where the prognosis of early stage disease is very good and even when local recurrences do occur they can present several years after treatment, the hospital resources required for annual follow-up examinations of what can be several hundreds of patients are financially significant. If, therefore, there is some method to estimate a maximum length of follow-up Tmax necessary, then cost savings of physicians' time as well as outpatient workload reductions can be achieved. In modern oncology where expenses continue to increase exponentially due to staff salaries and the expense of chemotherapy drugs and of new treatment and imaging technology, the economic situation can no longer be ignored. The methodology of parametric modelling, based on the lognormal distribution is described, showing that useful estimates for Tmax can be made, by making a trade-off between Tmax and the fraction of patients who will experience a delay in detection of their local recurrence. This trade-off depends on the chosen tail of the lognormal. The methodology is described for stage T1 and T2 breast cancer and it is found that Tmax = 4 years which is a significant reduction on the usual maximum of 10 years of follow-up which is employed by many hospitals for breast cancer patients. The methodology is equally applicable for cancers at other sites where the prognosis is good and some local recurrences may not occur until several years post-treatment.

Breast Neoplasms↗

PubMed2003

Methodological issues and controversies in clinical trials with child and adolescent patients with bipolar disorder: report of a consensus conference.

OBJECTIVE: To achieve consensus among researchers, pharmaceutical industry representatives, federal regulatory agency staff, and family advocates on a template for clinical trials of acute mania/bipolar disorder in children and adolescents. METHOD: The American Academy of Child and Adolescent Psychiatry, in collaboration with Best Practice, convened a group of experts from the key stakeholder communities (including adult psychiatrists with expertise in bipolar disorder) and assigned them to workgroups to examine core methodological issues surrounding the design of clinical trials and, ultimately, to generate a consensus statement encompassing: (1) inclusion/exclusion criteria, (2) investigator training needs and site selection, (3) assessment and outcome measures, (4) protocol design and ethical issues unique to trials involving children/adolescents, and (5) regulatory agency perspectives on these deliberations. RESULTS: Conference participants reached agreement on 18 broad methodological questions. Key points of consensus were to assign priority to placebo-controlled studies of acute manic episodes in children and adolescents aged 10-17 years, who may or may not be hospitalized, and who may or may not suffer from common comorbid psychiatric disorders; to require that specialist diagnostic "gatekeepers" screen youths' eligibility to participate in trials; to monitor interviewer and rater competency over the course of the trial using agreed upon standards; and to develop new tools for assessment, including scales to measure aggression/rage and cognitive function, while using the best available instruments (e.g., Young Mania Rating Scale) in the interim. CONCLUSIONS: Methodologically rigorous, large-scale clinical trials of treatment of acute mania are urgently needed to provide information regarding the safety and efficacy, in youth, of diverse agents with potential mood-stabilizing properties.

Adolescent↗