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PubMed2003

Triazinic herbicide determination by gas chromatography-mass spectrometry in breast milk.

A solid-phase extraction procedure using a graphitized carbon black cartridge for extraction and cleaning of a series of five triazines (atrazine, deethylatrazine, deisopropylatrazine, ametryne and prometryne) from breast milk samples was developed. Using a chemometric methodology, the optimisation of both the analysis time and the triazinic herbicide separation by gas chromatography-mass spectrometry (GC-MS) was then carried out with only 18 experiments. Detection and quantification limits for 1ml breast milk sample were, respectively, 0.3 and 1 ppb for each studied compound. The variation coefficients were less than 5% over the concentration range from 1 to 100 ppb. The accuracy was between 98.63 and 104.62% for each triazinic herbicide. The recovery was between 58.64 and 63.22% for the concentration range from 1 to 100 ppb for each triazinic herbicide. The assay was successfully applied to the analysis of several breast milk samples.

Gas Chromatography-Mass Spectrometry↗
PubMed1997

Does unhappiness make you sick? The role of affect and neuroticism in the experience of common physical symptoms.

The relative strength of both affective state and the personality trait neuroticism in predicting common physical symptoms was tested. The authors used an event-sampling design to overcome methodological limitations of past research in the area. Contrary to much previous research, neuroticism was found to be unrelated to reports of physical symptoms, although it was found to be related to unpleasant affective state. Unpleasant affect bore a strong concurrent relation to the frequency of reported symptoms. Temporal relations between experiences of unpleasant affect and subsequent symptoms were found for some individuals, but wide individual variability was seen in both the strength and direction of this linkage. The findings suggest that when individuals are asked to report their subjective experiences of physical illness without the necessity to retrospect over significant periods of time, unpleasant affective state is more strongly related to experiences of symptoms than is the trait neuroticism.

Adaptation, Psychological↗
PubMed2004

What is the effect of systemic anticancer treatment on cognitive function?

Treatment regimens for solid tumours have been extensively investigated for their physical toxic effects, but far less is known about the potential impairment of cognitive function by anticancer treatment regimens. Here, we review published studies that examined cognitive function in adult patients receiving systemic therapy for solid tumours. Our review suggests that patients can experience cognitive changes related to their treatment. However, several studies had methodological limitations, such as use of a limited sample size, lack of baseline assessment, and lack of control for potential confounding factors. Better designed clinical trials are required so that the difficulties patients face in terms of reduced cognitive function as a result of anticancer treatment can be fully elucidated. These trials should have sufficient statistical power and, importantly, should also be prospective.

Antineoplastic Agents↗
PubMed2006

Intellectual functioning in adults with ADHD: a meta-analytic examination of full scale IQ differences between adults with and without ADHD.

Although attention has been given to the intellectual functioning of children with attention-deficit/hyperactivity disorder (ADHD) relative to their non-ADHD peers, few studies have examined intellectual functioning in adults with ADHD. The purpose of the current investigation was to examine differences in intellectual ability between adults with and without ADHD via a meta-analytic review. Of the 33 studies meeting inclusion criteria, primary analyses focused on 18 studies representing 1,031 adults with ADHD and 928 non-ADHD, nonclinical comparison adults and containing Wechsler Adult Intelligence Scale (WAIS; D. Wechsler, 1955, 1981, 1994) Full Scale IQ scores or estimates. A significant effect was found such that adults with ADHD scored lower than non-ADHD adults on WAIS intelligence tests. However, this difference was small and not clinically meaningful. The presence of several moderators reflecting characteristics of the ADHD samples and study methodology suggested that only a subset of adults with ADHD (e.g., those with comorbid disorders) may experience lower general intellectual ability relative to non-ADHD comparison adults. Implications of the findings for clinical and research settings are presented as well as suggestions for improving methodology and reporting in future research.

Adult↗
PubMed2003

The autopsy in modern undergraduate medical education: a qualitative study of uses and curriculum considerations.

AIM: Medical education has undergone dramatic changes over the past decade. In the UK, the General Medical Council (GMC), the driving force behind curriculum reform, now requires curricula to be founded on a base of educational theory and research. This qualitative study investigated the roles of the autopsy within the context of the modern medical curriculum. METHODS: Using a phenomenological methodology, a non-representative 'theoretical sample' was selected to include medical educators with a wide range of teaching experience and responsibilities and disparate views both for and against the autopsy. Semistructured, tape-recorded interviews were undertaken to investigate the roles of the autopsy within the medical curriculum. Anonymised interview transcripts were subjected to a themed content analysis. RESULTS: Theoretical saturation was reached after 9 interviews. No new themes were added by a further 5 interviews. All the interviews were polythematic. In all, 43 themes were identified. In addition to confirming overt uses of the autopsy reported in previous studies, educators identified issues of curriculum design and development, the impact on the hidden curriculum, and a range of disadvantages and alternatives to the autopsy. CONCLUSIONS: Educators continue to perceive the autopsy as having a multifactorial role in providing the doctors of tomorrow with the appropriate knowledge and attitudes needed for the practice of medicine in the 21st century.

Autopsy↗
PubMed2006

Participant recruitment methods and statistical reasoning performance.

Optimal Bayesian reasoning performance has reportedly been elusive, and a variety of explanations have been suggested for this situation. In a series of experiments, it is demonstrated that these difficulties with replication can be accounted for by differences in participant-sampling methodologies. Specifically, the best performances are obtained with students from top-tier, national universities who were paid for their participation. Performance drops significantly as these conditions are altered regarding inducements (e.g., using unpaid participants) or participant source (e.g., using participants from a second-tier, regional university). Honours-programme undergraduates do better than regular undergraduates within the same university, paid participation creates superior performance, and top-tier university students do better than students from lower ranked universities. Pictorial representations (supplementing problem text) usually have a slight facilitative effect across these participant manipulations. These results indicate that studies should take account of these methodological details and focus more on relative levels of performance rather than absolute performance.

Adolescent↗
PubMed1987

Indirect mixed antiglobulin reaction (MAR) as a screening procedure for antisperm antibodies. I. Methodological studies.

Direct mixed antiglobulin reaction (MAR) cannot always be carried out because it requires motile spermatozoa in the patient's ejaculate. Therefore, the indirect MAR for IgG and IgA using donor spermatozoa sensitized with serum or seminal plasma from patients was investigated with the aim of developing a practical screening procedure for antisperm antibodies involving a characterization of the Ig-class of the antibodies. Samples from 23 men, 13 men with and 10 men without agglutinating antisperm antibodies, were used for the methodological experiments with the indirect MAR. Among three procedures to diminish the amount of nonbound immunoglobulin after sensitizing the donor spermatozoa with serial dilutions of serum or seminal plasma, a swim-up method was found to be optimal. The indirect MAR was carried out with glutaraldehyde-fixed sheep erythrocytes coated with IgG or IgA and various dilutions of anti-IgG and anti-IgA, respectively. These experiments led to a standardization of the indirect MAR, making it sensitive, easy to read, and allowing the reactions for IgG and IgA to be compared on an approximately equimolecular basis.

Autoantibodies↗
PubMed1982

Anatomy of the health worker effect - a critique of summary statistics employed in occupational epidemiology.

The "healthy worker effect," perhaps more accurately termed the "active worker effect" has been acknowledged by numerous investigators who have disregarded its significance. The healthy worker effect is expressed by SMRs (standardized mortality ratios) and influenced by the following three factors: (i) selection bias, (ii) improved socioeconomic status, and (iii) the conventional way of calculating SMRs. An examination of these three factors shows that selection for "employability" is probably the most significant factor for the healthy worker effect. For example, the shorter the observation, the smaller the SMR, and the stronger the health worker effect. Secondly, improved socioeconomic status as a result of employment has been shown to lower mortality. Last, although the SMR has the advantage of estimating relative risk in a small sample, it suffers many methodological pitfalls. It is recommended that at least three parameters be used to summarize mortality experience among the employed: (i) relative risk, (ii) attributable risk, and (iii) life expectancy.

Employment↗
PubMedDate not supplied

[Carcinogens and the Law 626/94: examples of application related to Title VII].

This paper is aimed at describing the state of the art with respect to the application of law 626/94, particularly with reference to the activities connected with the use of carcinogens at the workplace. To understand what is going on and what practical activities have been established we found it useful to look for practical examples in the field of carcinogenic risk assessment. We interviewed many colleagues and experts in a non-random sample of situations, and this paper briefly describes the methodological problems encountered and some specific results emerging from eight experiences. The examples described regard both large and small factories, in different fields of activity (chemical and pharmaceutical industries, transport, power production, ...), with different attitudes and traditions with regard to carcinogenic risk assessment, and also with different specific results in terms of risk evaluation. Two among the eight examples reported directly involved the activities performed by private consultants or territorial Public Services active in the field of prevention. The paper concludes with the indication of the problems encountered in the collection of information and with the suggestion that such experiences should be freely presented in the literature, thus offering an opportunity of public discussion and evaluation.

Carcinogens, Environmental↗
PubMed2004

Clarifying "meaning" in the context of cancer research: a systematic literature review.

OBJECTIVES: This article synthesizes the published literature related to the construct of meaning in the adult cancer population. METHODS: The databases CancerLit, CINAHL, Medline, PsychINFO, and the Journal of Psychosocial Oncology and PsychoOncology were searched to identify all studies related to meaning. The methodological aspects of all studies are described and the conceptual aspects are summarized only from those studies that met criteria for methodological rigor and validity of findings. The definitions for global meaning, appraised meaning, search for meaning, and meaning as outcome as proposed by Park and Folkman were used to interpret the findings. RESULTS: Of 44 studies identified, 26 met the criteria for methodological rigor. There is strong empirical and qualitative evidence of a relationship between meaning as an outcome of and psychosocial adjustment to cancer. SIGNIFICANCE OF RESULTS: The qualitative findings are considered useful for the development of psychosocial interventions aimed at helping cancer patients cope with and even derive positive benefit from their experience. However, variations in the conceptual and operational definitions, frequent reliance on homogeneous and convenience sampling, and the lack of experimental designs are considered to be methodological limitations that need to be addressed to advance the study of meaning in the context of cancer.

Adaptation, Psychological↗
PubMedDate not supplied

[Biological specimen banks: epidemiological tools and scientific enterprises].

In the last twenty years many large epidemiological studies have made efforts to collect material for biological specimen banks. These banks contain samples collected for short or long-term cryopreservation at low (e.g. -70 degrees C) or very low (-192 degrees C). This report describes general guidelines and methodological issues to take into consideration in designing and developing a biological specimen bank and is based on experience of three large scale studies. The author describes quality, quantity, methods to collect samples, and condition of cryopreservation that ensure both testing of scientific hypotheses and integrity of the stored samples. Feasibility and long-term storage effect studies should always be part of the design and the basic organization of a biological specimen bank. All operative choices a researcher makes in setting up a biological specimen bank have a direct impact on the future use of the biological samples and should be carefully considered.

Biological Specimen Banks↗
PubMed2004

Entrepreneurship of dietetic program graduates.

Successful dietetic program graduates must have an entrepreneurial mindset and skills to respond to environmental changes and consumer trends. The purpose of this study was to determine current or intended entrepreneurship by graduates of a Dietitians of Canada accredited university program, as influenced by self-efficacy stemming from entrepreneurial experiences in education or early career, as well as by internal and external factors. This study employed an exploratory descriptive methodology with a questionnaire mailed to a discrete sample. Ninety graduates completed and returned the questionnaire for a response rate of 55%. Data analysis included descriptive statistics, two-way table analysis, the chi-square test for independence, and Fisher's exact test. Significant relationships were found between self-efficacy scores and entrepreneurial action, specific entrepreneurial experiences and entrepreneurial intent and action, dietetic internship and intent, and belief in the importance of business skills and intent. Those with entrepreneurial intent and/or action identified creativity, dietetic education/internship, persistence, business skills, and family/friend support as helping factors. These results suggest that undergraduate, internship, and continuing education programs for dietitians should incorporate activities that develop entrepreneurial skills and contribute toward an entrepreneurial mindset.

Adult↗
PubMed1995

The dialectic in becoming a mother: experiencing a postpartum phenomenon.

In this study of the phenomenon of the postpartum period grounded theory methodology was used to investigate the experiences of first-time mothers during the first three months following their deliveries. The sample consisted of 12 primipara women and 3 multipara women. The data were generated by using unstructured interviews and field notes. Each woman was interviewed twice, the first time between 2 and 3 weeks postpartum, and the second time between 10 and 12 weeks postpartum. The final data for analysis consisted of: data generated through interviews, field notes, and the narratives of four mothers found in the non-fiction literature. Constant comparative analysis resulted in the generation of four categories and corresponding subcategories. These were: (1) Giving of Self; (2) Redefining Self; (3) Redefining Relationships; and (4) Redefining Professional Goals. The categories were not mutually exclusive. All the categories converged to provide support for the core variable 'Dialectic in Becoming a Mother'. The dialectic perspective demonstrated that, in becoming mothers, the women experienced transition, contradictions, tensions and transformations. A theoretical model was developed to show relationships among these major concepts. The findings of this study will be useful in effecting change in the provision of care to postpartum women and their families.

Female↗
PubMed2005

Childhood sexual abuse, social support, and psychological outcomes: a loss framework.

OBJECTIVE: The objectives of the study were: (a) to develop a scale to assess CSA-related loss among a college sample of CSA survivors (CSALM), (b) to examine the measure's convergent validity through associations among depression, alexithymia, coping, and social support, and (c) to test whether social support moderates the relation between multiple experiences of CSA and loss. METHOD: The study involved a survey methodology and included college-age women (n=116) reporting CSA experiences. RESULTS: Based on the Sexual Victimization Questionnaire (SVQ; [Finkelhor, D. (1979). Sexually victimized children. New York: The Free Press]), 90% of the sample reported CSA before age of 12, 12.3% (n=15) reported CSA before age 12 with an adult over 16, and 42.2% (n=49) reported CSA after age 12 with an adult. Exploratory Factor Analysis of the CSALM revealed a three-factor solution: (a) Loss of Optimism, (b) Loss of Self, and (c) Loss of Childhood. Convergent validity of several scales was evidenced through associations with depression, alexithymia, coping, and social support. Social support from family and friends was found to moderate the association between CSA experiences and loss dimensions. CONCLUSIONS: Findings provide preliminary psychometric support for the CSALM, a tool that will be useful in future investigations of loss among college-age CSA survivors. Findings also support using a loss framework to understand the current mental health of these survivors.

Adolescent↗
PubMed2005

Replication, variation and normalisation in microarray experiments.

INTRODUCTION: Microarray experiments often have complex designs that include sample pooling, biological and technical replication, sample pairing and dye-swapping. This article demonstrates how statistical modelling can illuminate issues in the design and analysis of microarray experiments, and this information can then be used to plan effective studies. METHODS: A very detailed statistical model for microarray data is introduced, to show the possible sources of variation that are present in even the simplest microarray experiments. Based on this model, the efficacy of common experimental designs, normalisation methodologies and analyses is determined. RESULTS: When the cost of the arrays is high compared with the cost of samples, sample pooling and spot replication are shown to be efficient variance reduction methods, whereas technical replication of whole arrays is demonstrated to be very inefficient. Dye-swap designs can use biological replicates rather than technical replicates to improve efficiency and simplify analysis. When the cost of samples is high and technical variation is a major portion of the error, technical replication can be cost effective. Normalisation by centreing on a small number of spots may reduce array effects, but can introduce considerable variation in the results. Centreing using the bulk of spots on the array is less variable. Similarly, normalisation methods based on regression methods can introduce variability. Except for normalisation methods based on spiking controls, all normalisation requires that most genes do not differentially express. Methods based on spatial location and/or intensity also require that the nondifferentially expressing genes are at random with respect to location and intensity. Spotting designs should be carefully done so that spot replicates are widely spaced on the array, and genes with similar expression patterns are not clustered. DISCUSSION: The tools for statistical design of experiments can be applied to microarray experiments to improve both efficiency and validity of the studies. Given the high cost of microarray experiments, the benefits of statistical input prior to running the experiment cannot be over-emphasised.

Algorithms↗
PubMed2006

A generic stepwise optimization strategy for liquid chromatography electrospray ionization tandem mass spectrometry methods.

The feasibility and advantages of using sophisticated chemometric tools in combination with the execution of thoroughly planned experiments to determine experimental conditions for optimal performance of an LC-ESI-MS/MS analysis is demonstrated. A stepwise strategy is proposed, which provides a controlled optimization procedure of the chromatographic quality (in terms of separation among the sample constituents) and maximizes the mass spectrometric signal of the selected product ions. Design of experiments (DOE) and response surface methodology are applied throughout the procedure. The stepwise approach has the advantage of dealing with the different optimization criteria separately, i.e. first ensuring sufficient chromatographic separation, then maximizing the amount of precursor ion entering the mass spectrometer, and finally generating high amounts of selected product ions. The experiments are performed on a linear ion trap mass spectrometer. Retention mapping using the band-tracking model is applied during LC development, which facilitates the optimization of segmented gradients. A set of different siderophores, strong iron chelates, is used as the model substances.

Journal Article↗
PubMed2000

Fatty acid composition of goat muscles and fat depots: a review.

In addition to the fat content of muscle and adipose depots, the fatty acid composition of lipids affects meat quality. Furthermore, relevant reports are difficult to use for comparisons, in that samples were collected from muscles and fat depots at various anatomical locations and experiments entailed different objectives, designs, procedures and methodologies. Nonetheless, based on currently available publications, according to a recent classification of meats by concentrations of potentially cholesterol-raising, and neutral, and cholesterol-lowering effects, average values for goat muscles appear better than for beef and lamb. Feeding dry diets seems to increase levels of unsaturated fatty acids and stearic acid in fat depots compared with milk or milk replacer. Increasing concentrate consumption can increase levels of odd-numbered and branched chain fatty acids in subcutaneous fat depots. With increasing age of unweaned kids, the level of stearic acid in fat depots decreases, and with increasing live weight of weaned kids levels of saturated fatty acids increase, and contents of monounsaturated fatty acids decrease in most fat depots. This review of a currently limited database indicates need for further experimentation to characterize interactions among factors such as breed, age and nutritional conditions in the fatty acid composition of carcass lipids of goats so as to gain a fuller understanding of goat meat quality.

Journal Article↗
PubMedDate not supplied

An effective algorithm for quick fractal analysis of movement biosignals.

The problem of numerically classifying patterns, of crucial importance in the biomedical field, is here faced by means of their fractal dimension. A new simple algorithm was developed to characterize biomedical mono-dimensional signals avoiding computationally expensive methods, generally required by the classical approach of the fractal theory. The algorithm produces a number related to the geometric behaviour of the pattern providing information on the studied phenomenon. The results are independent of the signal amplitude and exhibit a fractal measure ranging from 1 to 2 for monotonically going-forwards monodimensional curves, in accordance with theory. Accurate calibration and qualification were accomplished by analysing basic waveforms. Further studies concerned the biomedical field with special reference to gait analysis: so far, well controlled movements such as walking, going up and downstairs and running, have been investigated. Controlled conditions of the test environment guaranteed the necessary repeatability and the accuracy of the practical experiments in setting up the methodology. The algorithm showed good performance in classifying the considered simple movements in the selected sample of normal subjects. The results obtained encourage us to use this technique for an effective on-line movement correlation with other long-term monitored variables such as blood pressure, ECG, etc.

Algorithms↗