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PubMed1992

Further investigation of the prohapten concept: reactions to benzene derivatives in man.

p-Phenylenediamine (PPDA) is a strong contact sensitizer which is included in the standard patch test tray and which can also act as an indicator of allergy to related substances by virtue of cross-reactions. In a previous study, the pattern of cross-reactions between PPDA and related substances was investigated in the guinea pig to evaluate the prohapten concept. The results provided some support for this concept, but also indicated that a number of reactive intermediates might be behaving as haptens. This work has now been extended to an examination of the prohapten concept in man in PPDA-allergic subjects. These subjects were tested with 7 substituted benzenes, plus PPDA. Of these, the 1,4-substituted benzenes hydroquinone, Metol, PPDA and p-aminophenol are all capable theoretically of giving rise to benzoquinone by oxidation (after demethylation in the case of Metol). However, as had been the case in the guinea pig, only a limited degree of cross-reaction was observed. Only one of the subjects allergic to PPDA gave a clearly positive allergic reaction to benzoquinone. The data provided only limited support for the prohapten concept in terms of benzoquinone as the ultimate hapten for a range of 1,4-substituted benzenes. As indicated in the guinea pig, a range of reaction intermediates or indeed other oxidation products may be involved. So, for each molecule, the sensitizing activity and potential to give rise to cross-reactions may depend on the balance between routes of skin metabolism.

Adult↗
PubMed1993

The concept of multifactorial etiology of cancer.

The concept of causes is not just for professional philosophers to discuss. The epidemiologists also have to clarify how the concept is used since its meaning has profound implications for understanding basic measures of exposure-disease association. The concept of cause also has importance when designing a study or when analyzing epidemiological data. The paper describes the components cause model and its relationship with the mechanism of disease action. A measure of interaction is also presented which is based upon the components cause model. The common sense concept of causes also plays a fundamental role for the success of a health preventive programme according to the Health Belief Model. The component cause model may clarify causal patterns in situations when only a few of the exposed get the disease which the programme tends to prevent.

Animals↗
PubMedDate not supplied

Concept analysis of anxiety.

Anxiety, a nursing diagnosis that impacts clients in all settings and nurses throughout the profession, is clarified through the technique of concept analysis. Uses of the concept of anxiety in prominent theories of human behavior and in nursing are reviewed. Four critical attributes occurring in all cases of anxiety are identified--model cases, a related case, a contrary case, and an illegitimate case are presented. Antecedents to anxiety are identified. Consequences of anxiety are discussed. Empirical referents that demonstrate occurrence of the concept of anxiety are determined, classified, and related to critical attributes. This concept analysis provides an essential conceptual base for instrument development and clinical research on anxiety.

Anxiety↗
PubMedDate not supplied

Concept analysis of fear.

The nursing diagnosis fear is clarified through the technique of concept analysis. Uses of the concept of fear in prominent theories of human behavior and in nursing are reviewed. Five critical attributes occurring in all cases of fear are identified--a model case, a related case, a contrary case, and an illegitimate case are presented. Antecedents to fear are derived. Consequences of fear are discussed and are related to nursing interventions. Empirical referents that demonstrate occurrence of the concept of fear are determined, classified, and related to critical attributes. This concept analysis provides an essential conceptual base for instrument development and clinical research on fear.

Anxiety↗
PubMed1988

Seasonal distribution in conceptions achieved by artificial insemination by donor.

The distribution of conceptions after artificial insemination from a donor was studied in 259 conceptions at an artificial insemination clinic and found to be seasonal. Conception was not influenced by the number of donors or patients attending the clinic, the frequency of inseminations, or medical skill. Conception was more common from early winter until early spring (October to March) with a peak in November. As variables such as frequency of intercourse and ovulation were irrelevant in these women and highest sperm counts occur from February to March these results suggested a seasonal variation in the quality of the ovulated egg or endometrial receptivity. The waste of eggs after ovulation (or preimplantation conceptuses) at specific times of the year has implications in the treatment of infertility, particularly for in vitro fertilisation and gamete intrafallopian transfer.

England↗
PubMed2006

Impact of a theoretically based sex education programme (SHARE) delivered by teachers on NHS registered conceptions and terminations: final results of cluster randomised trial.

OBJECTIVE: To assess the impact of a theoretically based sex education programme (SHARE) delivered by teachers compared with conventional education in terms of conceptions and terminations registered by the NHS. DESIGN: Follow-up of cluster randomised trial 4.5 years after intervention. SETTING: NHS records of women who had attended 25 secondary schools in east Scotland. PARTICIPANTS: 4196 women (99.5% of those eligible). INTERVENTION: SHARE programme (intervention group) v existing sex education (control group). MAIN OUTCOME MEASURE: NHS recorded conceptions and terminations for the achieved sample linked at age 20. RESULTS: In an "intention to treat" analysis there were no significant differences between the groups in registered conceptions per 1000 pupils (300 SHARE v 274 control; difference 26, 95% confidence interval -33 to 86) and terminations per 1000 pupils (127 v 112; difference 15, -13 to 42) between ages 16 and 20. CONCLUSIONS: This specially designed sex education programme did not reduce conceptions or terminations by age 20 compared with conventional provision. The lack of effect was not due to quality of delivery. Enhancing teacher led school sex education beyond conventional provision in eastern Scotland is unlikely to reduce terminations in teenagers. TRIAL REGISTRATION: ISRCTN48719575 [controlled-trials.com].

Abortion, Induced↗
PubMedDate not supplied

Medical-concept models and medical records: an approach based on GALEN and PEN&PAD.

OBJECTIVES: To investigate the issues raised in applying a preliminary version of the GALEN compositional concept reference (CORE) model to a series of radiographic reports, and to demonstrate that the same underlying concept model could be used in conjunction with both a detailed, fine-grained model of medical records based on that used in the PEN&PAD project and with other more conventional medical-record models. DESIGN: Following analysis and representation of concepts from a set of reports, a single report was taken as a "case study." This report was analyzed in detail in its entirety and represented using each of the medical-record models. RESULTS: The reports were successfully represented within the limits of the study, but a number of significant issues were raised. CONCLUSION: The compositional approach plus the PEN&PAD medical-record model allowed detailed information in the radiographic report to be represented, including information about the inferences and the clinical process. The resulting representation was large, and more compact representations may be necessary for some systems. Alternative encapsulations of the information as might be used in such systems were successfully prepared. The compositional approach avoided many issues that often cause controversy in the design of traditional coding and classification systems, but it raised other issues, including the handling of ambiguity and underspecification, linkage to information not explicitly present in the report, and questions concerning the focus of individual concepts. All work is preliminary and definitive conclusions await further studies and systematic evaluation.

Decision Making, Computer-Assisted↗
PubMed2006

Lost in translation: a genealogy of the "social capital" concept in public health.

STUDY OBJECTIVE: To examine the genealogy of the social capital concept in public health, with attention to the epistemological concerns and academic practices that shaped the way in which this concept was translated into public health. DESIGN: A citation-network path analysis of the public health literature on social capital was used to generate a genealogy of the social capital concept in public health. The analysis identifies the intellectual sources, influential texts, and developments in the conceptualisation of social capital in public health. PARTICIPANTS: The population of 227 texts (articles, books, reports) was selected in two phases. Phase 1 texts were articles in the PubMed database with "social capital" in their title published before 2003 (n = 65). Phase 2 texts are those texts cited more than once by phase 1 articles (n = 165). MAIN RESULTS: The analysis shows how the scholarship of Robert Putnam has been absorbed into public health research, how three seminal texts appearing in 1996 and 1997 helped shape the communitarian form that the social capital concept has assumed in public health, and how both were influenced by the epistemological context of social epidemiology at the time. CONCLUSIONS: Originally viewed in public health research as an ecological level, psychosocial mechanism that might mediate the income inequality-health pathway, the dominance of the communitarian approach to social capital has given disproportionate attention to normative and associational properties of places. Network approaches to social capital were lost in this translation. Recovering them is key to a full translation and conceptualisation of social capital in public health.

Health Services Research↗
PubMed1998

Tell me what's wrong with me: a discourse analysis approach to the concept of patient autonomy.

BACKGROUND: Patient autonomy has gradually replaced physician paternalism as an ethical ideal. However, in a medical context, the principle of individual autonomy has different meanings. More knowledge is needed about what is and should be an appropriate understanding of the concept of patient autonomy in clinical practice. AIM: To challenge the traditional concept of patient autonomy by applying a discourse analysis to the issue. METHOD: A qualitative case study approach with material from one consultation. The discourse is interpreted according to pragmatic and text-linguistic principles and provides the basis of a theoretical discussion of different concepts of patient autonomy. RESULTS: The consultation transcript illustrates how the patient's wishes can be respected in real life. The patient, her husband and the doctor are all involved in the discourse dynamics, governed by the subject matter, namely her mental illness. CONCLUSION: We suggest a dynamic and dialogue-based conception of autonomy as adequate for clinical purposes. These perspectives, based on mutual understanding, take communication between patient and doctor as their starting point. According to this approach, autonomy requires a genuine dialogue, an interpersonal mode of being which we choose to call "authentic interaction".

Depressive Disorder↗
PubMed2000

Is there a coherent social conception of disability?

Is there such a thing as a social conception of disability? Recently two writers in this journal have suggested not only that there is a coherent social conception of disability but that all non-social conceptions, or "medical models" of disability are fatally flawed. One serious and worrying dimension of their claims is that once the social dimensions of disability have been resolved no seriously "disabling" features remain. This paper examines and rejects conceptions of disability based on social factors but notes that physical and mental conditions which disadvantage the individual have social dimensions.

Deafness↗
PubMed2005

Using student feedback to construct an assessment rubric for a concept map in physiology.

Constructing quality assessment rubrics can be challenging, especially when they are used for integrated, group-centered, applied learning. We describe a collaborative assessment task in which groups of second-year dentistry students developed a complex concept map. In groups of four, the students were given a written, simulated, medical history of a patient and required to construct a concept map illustrating relevant pathophysiological concepts and pharmacological interventions. This report describes a research project aimed at making educational goals of the task more explicit through investigating student and faculty member understandings of the criteria that might be used to assess the concept map. Information was gathered about the perceptions of students in relation to the learning goals associated with the task. These were compared with faculty member perceptions. The findings were used to develop an assessment rubric intended to be more accessible to learners. The new rubric used the language of both faculty members and students to more clearly represent expectations of each criterion and standard. This assessment rubric will be used in 2005 for the next phase of the project.

Data Collection↗
PubMed2003

Relationship of vaginal bacteria and inflammation with conception and early pregnancy loss following in-vitro fertilization.

OBJECTIVE: The aim of this study was investigate the impact of vaginal flora and vaginal inflammation on conception and early pregnancy loss following in-vitro fertilization (IVF). METHODS: We enrolled 91 women who were undergoing IVF. At embryo transfer (ET), all of the women had quantitative vaginal culture, ET catheter-tip culture, and vaginal Gram stain scored for bacterial vaginosis and quantitated for polymorphonuclear leukocytes (PMNs). Conception and early pregnancy loss were compared with culture and Gram stain results. Statistical analyses included the Chi-square test, Fisher's exact test and the Mann-Whitney U-test. RESULTS: The overall live birth rate (LBR) was 30% (27/91), and the rate of early pregnancy loss was 34% (14/41). In women with bacterial vaginosis, intermediate flora and normal flora, the conception rates were 30% (3/10), 39% (12/31) and 52% (26/50), respectively (p = 0.06 for trend). Early pregnancy loss occurred in 33% (1/3), 42% (5/12) and 31% (8/26) of women, respectively (p = 0.06, comparing intermediate and normal flora). The vaginal log concentration of hydrogen peroxide-producing lactobacilli was 7.3 +/- 1.7 in women with a live birth (n = 27) and 4.9 +/- 2.5 in those with early pregnancy loss (n = 14) (p = 0.1). CONCLUSIONS: IVF patients with bacterial vaginosis and with a decreased vaginal log concentration of hydrogen peroxide-producing lactobacilli may have decreased conception rates and increased rates of early pregnancy loss. A larger prospective treatment trial designed to evaluate the impact on IVF outcomes of optimizing the vaginal flora prior to IVF may be warranted.

Abortion, Spontaneous↗
PubMed1993

The organizational concept and vertebrates without sex chromosomes.

The diversity in vertebrate reproductive patterns provides natural experiments that yield new insights into behavioral endocrinology. Discussed here is the generality of the concept of an organizing sex during sexual differentiation. In its present form the Organizational Concept emphasizes hormonally induced organization of the male phenotype, with the female phenotype being the neutral or default condition. Does this concept extend to vertebrates lacking genotypic sex determining mechanisms? The answer appears to be No. In species with temperature-dependent sex determination, each embryo has an equal probability of developing into either a male or a female; there is no heritable genetic predisposition for sex determination. In species with behavior-dependent sex determination, sex-change occurs during adulthood as a result of perceived alterations in the social environment. In parthenogenetic species, only female individuals exist, yet they display both male-like and female-like "sexual" behaviors. In contrast to the contemporary view of the Organizational Concept, let us assume that the male pattern is derived and imposed upon the ancestral female pattern. If this perspective is taken, several avenues of study are identified: (i) the importance of sexual similarities; (ii) extending the principle of complementarity of sexual behaviors to the brain; (iii) temperature modulation of sexual differentiation, and (iv) the role of the brain in sex determination.

Animals↗
PubMed1985

Alternatives to the species concept for virus taxonomy.

The species concept seems to be inescapably based on the occurrence, in a population, of regular genetic interchange which leads to the formation of common gene pools and on the presence of barriers to interchange which distinguish one gene pool from another. Present knowledge indicates that some types of viruses (e.g. Orthomyxoviridae, Reoviridae) may exchange genes and have a gene-pool population structure; application of the species concept here is legitimate and likely to be feasible in practice. However, it seems that other types of viruses (e.g., tobamoviruses, tombusviruses) do not indulge in regular gene exchange and that common gene pools, distinct from each other, do not occur. Rather, there is clonal multiplication, accumulation of variants, and a fanwise radiation of types with little or no genetic exchange across the rays of the fan. Here, the species concept cannot usefully be applied at either the theoretical or the practical level. If viruses within some major groups are not amenable to being classified and named as species, it follows that attempts to apply the species concept to all viruses should be abandoned. An alternative system that can embrace all cases is already used by plant virologists and merits careful examination by others. Adoption of a 'nonspecies' general approach need not exclude the proposition that in some instances virus species do exist and can be identified and named, as special subsets of the general case. If we cease to aim for the universal pigeonholing of viruses into genera and species, binomial latinized names lose their chief justification.(ABSTRACT TRUNCATED AT 250 WORDS)

Genes, Viral↗
PubMed1989

Seasonal variation in conception does not appear to influence the rate of prenatal diagnosis of nondisjunction.

A seasonal effect on ovulation patterns and conception rates is well documented in animal studies. The etiology of reported variation in human fertility is, however, uncertain. Abnormal ovulation has been implicated in the etiology of aneuploid conceptions, many of which abort spontaneously. To investigate the possibility that the frequency of aneuploidy reflects seasonal variation in ovulation patterns, we analyzed 5,292 consecutive prenatal karyotypes obtained from 1985 to 1987. Karyotypes were logged according to month and year of conception. Results were evaluated for cyclicity using frequency spectrum and time series analysis. Variation in the number of prenatal diagnostic procedures corresponded to known peaks in conception and delivery rates. No significant monthly or quarterly trend in the total rate of trisomies or in the rate of trisomy 21 was demonstrated. Although the sample size in this study may not be adequate to detect minor effects, seasonal variation does not appear to be a major determinant of nondisjunction rates in the population referred for prenatal diagnosis.

Aneuploidy↗
PubMed1987

The development of the concept of reactive psychoses.

Although reactive (psychogenic) psychoses have no doubt occurred throughout the history of mankind, it is only during the last century that the corresponding concept has been defined, beginning with Sommer's definition of the term 'psychogenic' and Jaspers' distinctions between 'reaction' and 'process', and between 'neurosis' and 'psychosis', respectively. A change in Kurt Schneider's nosological concepts induced the majority of German-speaking psychiatrists to avoid the concept of psychogenic psychoses. The very varying use of the concept of reactive psychoses in different countries is described and discussed, with special regard to implications for psychiatric epidemiology.

Adjustment Disorders↗
PubMed1987

Continental viewpoints on the concept of reactive psychoses.

Although the Scandinavian concept of reactive psychoses relates to K. Jaspers and although Kretschmer described the prototype of a psychosis of psychogenic/reactive origin (Der sensitive Beziehungswahn), the concept is not so commonly used in German-speaking countries. Important reasons for this refusal may be (1) the sharp distinction between psychosis (which may be explained but not understood) and understandable reactions, which was stressed in rather influential German psychiatric schools in the middle of the century, and (2) the aim of stressing psychological understanding in a broad spectrum of psychiatric illnesses in the Swiss tradition, where the demarcation of particular reactive psychoses seemed to be superfluous. The development of modern concepts stressing the multidimensionality in the etiology of the main groups of psychiatric disorders was certainly influenced by the concept of reactive psychoses but passed it.

Adjustment Disorders↗
PubMed1987

The development of the entire end-systolic pressure-volume and ejection fraction-afterload relations: a new concept of systolic myocardial stiffness.

In this study we introduce a new concept of systolic myocardial stiffness that extends the Suga-Sagawa maximum ventricular elastance concept to the myocardium. End-systole is defined as the time of maximum systolic myocardial stiffness (max Eav), which we examined for its load independence and sensitivity to changes in the inotropic state and to heart rate. Seven adult mongrel dogs were instrumented with ultrasonic crystals for measurements of long and short axes and left ventricular wall thickness, and a high-fidelity micromanometer was inserted for measurement of left ventricular pressures. Preload and afterload were altered by inferior vena cava occlusion, nitroprusside, angiotensin II, atropine, propranolol, and various combinations with propranolol. End-systolic stress-strain relations (slope: max Eav) were linear in all seven dogs, implying that end-systolic myocardial stiffness is independent of end-systolic stress. Changes in max Eav (for constant preload and afterload) reflected changes in the ejection fraction; max Eav was also insensitive to propranolol and to changes in heart rate over the range from 120 to 180 beats/min. End-systolic pressure-volume relations (ESPVRs), derived analytically from these stress-strain relations, were nonlinear, and estimates of volume at zero stress (Vom) were always positive. On the other hand, ESPVRs obtained on the basis of the Suga-Sagawa maximum ventricular elastance concept, were linear, and volume at zero pressure (Vop) estimated by linear extrapolation was negative in one case. Based on the concept of systolic myocardial stiffness, the slope of the ESPVR varies with end-systolic volume and attains its maximum value (Emax) at zero end-systolic pressure. Normalization of Emax with Vom demonstrated a close relationship to max Eav. Thus both max Eav and Vom and Emax are ideal variables for assessing changes in myocardial contractility when preload and afterload are constant. Furthermore, Vom and max Eav permit development of the entire ejection fraction-afterload relationship for a given preload, thus providing a method for comparing myocardial contractile states between ventricles.

Animals↗