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German constitutional doctrine in the 1920s and 1930s and pitfalls of the contemporary conception of normality in biology and medicine.

From the end of the First World War, a broad discussion took place within the framework of the revived German constitutional teaching on the question of the physical normality of man. The founder of the so-called statistical concept of normality, which preceded the still widespread normal (reference) interval concept, is H. Rautmann, who gave it the character of a tool for discriminating between health and disease. Among some of his successors (Bauer, Borchardt, Günther), however, it was considered more a means of establishing a type, without supposing any precise relation between the frequency of a character in the population and the probability of the occurrence of disease. The concept of a statistical norm as a certain region of the variation range of a character determined by the parameters of Gaussian distribution was criticized both by the supporters of the ideal norm (Hildebrandt) and those who were in favour of a 'personal' norm (Grote). The underlying motifs of these three conceptions of normality influenced German constitutional doctrine until after the end of the Second World War, but without a satisfactory solution to the diagnosis of physical normality being found. Since the 1950s, world medicine has moved more and more in the direction of prevention, with the emphasis on a study of individual dispositions to disease and its precursors. In this connection a new view of health has gained importance whereby it is considered a smoothly gradated condition, not sharply distinguished from disease ('continual' model of health and disease as opposed to the previous 'alternative' model). The purpose of diagnostic characters is no longer merely to place patients in clearly defined categories as healthy or affected by one disease or another, but has taken on the function of indices of the disposition to disease among those who exhibit 'gross normality'. Discrimination between the alternative and continuous models allows a clarification to be made of the sources of the confusion in which the pre-war concept of statistical normality had found itself. Today many exceptions are known to the rule that the functional optimum lies in the region of the population mean, both for the population as a whole and for individuals; and immense variability has been found in the manner in which individuals in the population attain health.(ABSTRACT TRUNCATED AT 400 WORDS)

Anthropometry↗

Frequency of non-hormonal contraception around conception and association with congenital malformations in offspring.

A case-control study using data on deliveries in the mid-1970s at five Connecticut hospitals (cases, n = 1427; controls, n = 3001) found little relationship between delivery of a malformed infant and use by the mother of nonhormonal contraceptive methods at conception. Of particular interest was the lack of an association with use of the rhythm method (odds ratio (OR) = 1.02, 95% confidence limits (CL) = 0.73, 1.42), spermicides (OR = 1.26, 95% CL = 0.85, 1.85) at conception and a modest association for the intrauterine device (IUD) one week before conception (OR = 1.99, 95% CL = 0.98, 4.04). Continued use of the IUD after conception may further increase the risk for malformations but this observation was statistically unreliable in the present study. Mothers of newborns with cleft lip and palate (OR = 2.91) and congenital hydrocele (OR = 4.64) were more frequent rhythm users at conception, and mothers of newborns with multiple anomalies had more recent IUD exposure (OR = 9.87), but these and all other specific congenital malformation groups were not significantly related to any non-hormonal contraceptive after adjustment for multiple observations. Potentially confounding maternal risk factors were controlled.

Adult↗

Association of delayed conception with caffeine consumption.

This cross-sectional study investigated the relation between intake of caffeine-containing beverages and time to conception in a population of 1,909 married women in New Haven, Connecticut, between May 12, 1980 and March 12, 1982. Women were interviewed shortly after the first prenatal visit regarding the length of time taken to conceive the index pregnancy, consumption of caffeine during pregnancy, and other exposures occurring prior to and during pregnancy. In logistic regression analyses, intake of caffeine from coffee, tea, and caffeinated soft drinks was associated with an increased risk of a delay of conception of 1 year or more. Compared with no caffeine use, consumption of 1-150 mg/day of caffeine resulted in an odds ratio for delayed conception of 1.39 (95% confidence interval (CI) 0.90-2.13), consumption of 151-300 mg/day of caffeine was associated with an odds ratio of 1.88 (95% CI 1.13-3.11), and that of over 300 mg/day (the equivalent of approximately three cups of coffee) resulted in an odds ratio of 2.24 (95% CI 1.06-4.73), after controlling for last method of birth control used, parity, and number of cigarettes per day. When the risk of conception for each cycle was examined using a discrete analogue of the Cox proportional hazards model, women who reported drinking over 300 mg/day of caffeine had a 27% lower chance of conceiving for each cycle, and those who reported drinking less than 300 mg/day had a 10% reduction in per cycle conception rates compared with women who consumed no caffeine. Risks for coffee, tea, and colas were examined simultaneously in logistic models and were found not to improve the fit of a model that contained a variable for total caffeine intake from all sources.

Beverages↗

The diagnosis of male infertility--prospective time-specific study of conception rates related to seminal analysis and post-coital sperm-mucus penetration and survival in otherwise unexplained infertility.

Infertile women without any inherent female infertility factors and able to secrete normal cervical mucus were studied prospectively in relation to post-coital sperm-mucus penetration (PCT) and their partner's seminal analysis, excluding men with azoospermia. Time-specific cumulative conception rates calculated as for life-table analysis were related to each measured seminal variable on routine analysis of 2-3 samples (volume, density, proportion with progressive motility, and proportion with normal morphology); to various derivatives from combinations of these variables; to seminal findings after vital staining; and to the PCT results. The best seminal predictor of fertility was the motile normal sperm density (MNSD), the 18 month conception rates being 57.4% +/- 4.6 (SE) and 30.2% +/- 5.9 (ratio 1.9, P less than 0.001) above and below a derived threshold value of 4 x 10(6)/ml. The PCT led to rates of 55.6% +/- 4.3 and 14.9% +/- 5.1 (ratio 3.73, P less than 0.001) for positive and negative results, respectively. The PCT also gave rise to a significantly distinct intermediate poor-positive sub-group (conception rate 30.6% +/- 9.0). Seminal analysis (the MNSD) did not affect the conception rate associated with a positive PCT but helped to discriminate further with a negative PCT (conception rates 22.5% +/- 8.7 with an MNSD above 4 x 10(6)/ml versus 5.6% +/- 4.8 below, P less than 0.05). The PCT was the single best predictor of fertility but seminal analysis (the MNSD) was of additional value after a negative PCT.

Cervix Mucus↗

Predictive value of human chorionic gonadotrophin in the outcome of early pregnancy after in-vitro fertilization and spontaneous conception.

This prospective study analyses the value of the beta-subunit of human chorionic gonadotrophin (beta-HCG) in 120 pregnancies obtained after in-vitro fertilization (IVF)--embryo transfer. Spontaneous conception cycles (n = 16) were also analysed allowing a comparison between these two forms of conception. Of the 120 clinical pregnancies, 48 started as single gestations and 50 started with two or more sacs. There were 14 clinical abortions and eight ectopic pregnancies. All subjects had blood samples taken under a fixed protocol on days 11, 14, 17, 20 and 23 after follicular aspiration. Weekly samples were obtained thereafter until day 60 from ovum retrieval. Transvaginal ultrasounds were performed at weekly intervals, starting on day 23 after follicular aspiration. In spontaneous conception cycles blood samples were obtained daily, starting on the day of follicular rupture. In spontaneous conception cycles and in IVF-embryo transfer conceptions, the doubling time (DT) of beta-HCG was 1.4 +/- 0.3 and 1.6 +/- 0.4 days respectively. This difference was not significant. In multigestations, the DT was 1.5 +/- 0.3 days. The absolute values of beta-HCG in early spontaneous gestations were significantly higher than in IVF-embryo transfer cycles, suggesting that the blastocyst implants with less cellular mass when initiated in vitro as compared with the in-vivo condition. The early prediction of ectopic pregnancy and spontaneous clinical abortion was analysed by the beta-HCG profile as well as the absolute values in comparison to normal pregnancies. Both parameters showed significant differences as early as the interval between days 11 and 23 from follicular aspiration.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Spontaneous↗

Pre-conception diabetes care in insulin-dependent diabetes mellitus.

Prospective studies of pre-conception diabetes care have confirmed its positive impact on the incidence of malformations by improving glycaemic control. Less information is available on the impact of pre-conception care on maternal and neonatal morbidity. This audit addresses its impact on timing and mode of delivery, incidence of macrosomia and rate of admission to neonatal unit care in addition to sociodemographic factors which may influence attendance at such a service. Attenders were more likely to be in a stable relationship and be non-smokers. They were more likely to book for antenatal care earlier and with a lower glycated haemoglobin. There were no early deliveries (i.e. < 30 weeks) or small for gestational age (SGA) babies in those who attended for pre-conception care and no neonatal deaths. Admission to NNU care was reduced by 50% in those who attended for pre-conception care. Although the rate of macrosomia was reduced, there was no impact on the Caesarian section rate. A pre-conception diabetes clinic may have a positive impact on neonatal morbidity.

Cesarean Section↗

Conditions at conception and risk of menstrual disorders.

In a case-control study, we evaluated the association of the risk of menstrual disorders with four periconceptional factors: short preceding interpregnancy interval (< 6 months), low (< or = 19 years) or high (> or = 40 years) maternal age at conception, and month of conception. We divided 919 women who had visited a fertility clinic between 1991 and 1995 into three categories: cases (with mean menstrual cycle length > or = 42 or < or = 21 days, or a variation of > or = 14 days between cycles, or amenorrhea, N = 294), controls (with cycles within a range of 25-35 days and variation < or = 7 days, N = 520), and intermediates (N = 105). A self-administrable questionnaire was mailed, asking for information about maternal reproductive history and age, and potential confounders such as smoking, exercise, and level of education. Response (77%) differed little among cases, intermediates, and controls. We found elevated risks for short pregnancy intervals [adjusted odds ratio (OR) = 2.04; 95% confidence interval (CI) = 1.04-4.02] and advanced maternal age (OR = 3.24; 95% CI = 1.27-8.30) but not for low maternal age (OR = 0.58; 95% CI = 0.11-3.14) (cases vs controls). We found similar effects for intermediates vs controls. The distribution of month of conception did not differ much from controls for both cases and intermediates. The results indicate that conception after short pregnancy intervals or at advanced maternal age increases the risk of menstrual disorders in daughters. The precise etiology is unclear, but it may lie in the quality of the oocyte at conception.

Adolescent↗

Concept activation and coordination of activation procedure require two different networks.

In the present study, we used EEG-coherence analysis to assess general regional changes in neuronal activity related to semantic retrieval, testing the hypothesis that concept activation and coordination procedures are neurobiologically distinguishable. Four subjects had to decide whether or not a capital letter and a lower case letter have the identical name (e.g. Aa). This task requires two mental procedures: (i) the activation of concepts and (ii) their coordination, particularly when the interstimulus interval is shorter than the duration of concept activation. This memory retrieval of a concept appears to be subserved by two distinct networks: the left parietotemporal region for concept activation and the prefrontal region for coordination.

Adult↗

Priorities of nutritional concepts assigned by health professionals and students.

Medical faculty, practicing physicians, medical students, and dietitians/nutritionists rated nutritional concepts as to their importance for inclusion in the medical school curricula and indicated the best method of accomplishing this. Ten concepts were rated "essential." They related to biochemical and physiological aspects of nutrition; nutrition in pregnancy, lactation, growth, development, maturity, and old age; nutritional management in disease; drug and diet interrelationships; and critiques of popular dietary regimens. Ranked as "important" were eight concepts regarding sources of nutrition information; evaluation of nutritional status; recommended dietary allowances; and food additives, naturally occurring food toxins, and nutrient composition of foods. Based on results of this study, the authors make recommendations regarding nutritional concepts that should be included in medical school curricula and how these concepts should be incorporated.

Attitude of Health Personnel↗

A survey of medical school teachers to identify basic biomedical concepts medical students should understand.

Insights from the cognitive sciences indicate a continuing need for physicians to understand conceptual knowledge from the basic sciences, despite recent concerns regarding the increasing amount of information in medicine and the growing emphasis on performance skills. A 1987 survey of selected basic science and clinical teachers in North American medical schools was undertaken to identify basic biomedical concepts that are important in the practice of medicine and to specify how difficult these are for students to learn, apply, or both. Responses from faculty (nominated by their deans to answer the survey) from 82% of the medical schools indicated considerable agreement between the basic science teachers and clinical teachers on the relative importance of a set of biomedical concepts, and showed relatively minor levels of disagreement on how difficult these concepts are. The judgments of these teachers could prove extremely useful in (1) determining concepts that--because of their importance--should receive special attention in curriculum efforts, and (2) determining concepts that--because of their difficulty--need "special handling."

Canada↗

An analysis of the concept of risk.

The meaning of the word "risk" has changed throughout history. Once a neutral term, risk has come to represent a combination of probability and something adverse or dangerous. Phenomena that were previously referred to as hazards, dangers, or uncertainties are now labeled as risks. Although risk touches every aspect of health and human welfare, the dimensions of risk as conceptualized in the fields of epidemiology, nursing science, medical science, and lay health are qualitatively different. Risk has not been examined as a concept in nursing literature or research, although risk and related terms are defined in a few nursing textbooks. Using the evolutionary method of concept analysis, risk is examined as a concept. This analysis was undertaken to define and clarify the concept and dimensions of risk as they relate to risk for disease. A sound understanding of risk as a concept is critical for developing an empirical knowledge base in nursing and directing nursing research examining issues related to risk for developing diseases such as cancer.

Epidemiologic Studies↗

The future of the de minimis concept.

How low is low enough? Is "close to zero? Does detectability define importance? These and similar questions are addressed in this paper, which considers the concept of a "practical zero" or de minimis level of radiation and the future applications of that concept. After defining the concept and some widely used terms and summarizing the current status of the de minimis approach, this article surveys the activities of standards-setting and regulatory bodies throughout the world and their possible future approaches to applying the de minimis concept. Applications include conventional disposal of very-low-level wastes, ocean dumping, decontamination and decommissioning guidelines, and truncation of as low as reasonably achievable and collective dose calculations. Implications in areas beyond low-level radiation control are also addressed. These areas include nuclear accident risks and the risks associated with use of hazardous materials. The application of the de minimis concept to risks of all types is discussed, with a particular emphasis on the risks of carcinogenesis. The paper also presents a summary of methods for quantitatively setting actual levels that are deemed de minimis in specific cases. Finally, the problems inherent in a de minimis approach are discussed and an attempt is made to predict future developments.

Government Agencies↗

A neurosciences internship and graduate nurse role conception.

Registered nurse (RN) turnover is a severe problem many hospitals face in today's health care climate. A study was conducted of a graduate nurse (GN) neurosciences internship established in a large metropolitan teaching hospital located in southwestern Tennessee to determine the internship's effect upon role conception of GNs. Thirty-two GNs enrolled in the internship comprised the experimental group, and 22 GNs in traditional orientation were the control group. Data collection instruments consisted of Corwin's Role Conception tool and a demographic questionnaire designed to examine variables that could influence professional role conception. Both instruments were completed at the beginning of employment, and Corwin's Role Conception repeated after completion of the first six months of practice. At this time audiotaped interviews were conducted by a nurse counselor to collect qualitative data from ten randomly selected informants from each group. Results revealed no significant differences in the two groups regarding changes in role conception as measured by Corwin's instrument. Audiotaped interviews brought to light many concerns of new GNs with regard to inadequate staffing, the charge nurse role, coping with the stress of the professional nurse role and new attitudes toward the field of the neurosciences. Implications for nurse administrators include the need to: be aware of the stresses to which new GNs are exposed; examine traditional practices such as the charge nurse role and staffing patterns; determine whether nursing internships, such as the neurosciences internship can improve the attitudes of GNs toward their specialty.

Adult↗

Concept-oriented indexing of video databases: toward semantic sensitive retrieval and browsing.

Digital video now plays an important role in medical education, health care, telemedicine and other medical applications. Several content-based video retrieval (CBVR) systems have been proposed in the past, but they still suffer from the following challenging problems: semantic gap, semantic video concept modeling, semantic video classification, and concept-oriented video database indexing and access. In this paper, we propose a novel framework to make some advances toward the final goal to solve these problems. Specifically, the framework includes: 1) a semantic-sensitive video content representation framework by using principal video shots to enhance the quality of features; 2) semantic video concept interpretation by using flexible mixture model to bridge the semantic gap; 3) a novel semantic video-classifier training framework by integrating feature selection, parameter estimation, and model selection seamlessly in a single algorithm; and 4) a concept-oriented video database organization technique through a certain domain-dependent concept hierarchy to enable semantic-sensitive video retrieval and browsing.

Abstracting and Indexing↗

A new approach to modeling daily probabilities of conception.

Standard conception probabilities models assume that different acts of intercourse make independent contributions to the probability of conception in viable cycles. We propose an alternative, approximate model based on the assumption that the act of intercourse closest to the time of maximum fertility is the one most likely to have caused conception. We describe an adaptive algorithm [the most fertile intercourse day (MFID) algorithm] that estimates the most fertile intercourse day in each cycle. The approach is easily extended to include covariates and random between-couple differences in fecundability that affect the probability of conception in a given cycle. Reanalyses of two data sets reported in the literature are presented. Estimates of the probability of conception during the most fertile period of the cycle and of the effects of covariates are similar to estimates found using standard models.

Algorithms↗

Prolactin concentrations in normal menstrual cycles and conception cycles.

Plasma prolactin concentrations were measured daily throughout twenty-three menstrual cycles from regularly ovulating women. In five of the cycles conception occurred spontaneously. The frequency distribution of prolactin concentrations was calculated and an appropriate linear transform obtained. Means and 95% confidence limits were determined by inspection of the logarithmic probability plots and these gave mean concentrations (and ranges) of 302 (106-871) mU/1 for the nonconception cycles and 178 (58-550) mU/1 for the conception cycles. Distribution of prolactin concentrations was log-normal in all cases, although the population containing the conception cycles was distinct from the population of non-conception cycles. It is suggested that the normal range found in ovulating women is 80-800 mU/1 but that for conception to occur levels should be slightly lower and approximate to the range 60-600 mU/1. Thus the lower limit of normal is about 60 mU/1 and the upper limit about 800 mU/1. Any concentration over 800 mU/1 should be designated as hyperprolactinaemia.

Female↗

An analysis of the concept of humour and its application to one aspect of children's nursing.

This paper explores the concept of humour by exposing it to the analytical framework of Walker and Avant. The paper then seeks to examine the benefit humour has in child and parent health education. Whilst the author argues that the framework utilized to analyse the concept is positivistic in nature, emphasis is given to the value of humour and the various meanings ascribed to it in the real world. Humour was used consciously by seven registered children's nurses and one student nurse completing her final placement of the branch in children's nursing. The aim being to reduce parental anxiety and enhance feelings of confidence and competence within the parental groups. The findings of this small study indicated that whilst humour is delicate and may be inappropriate in certain settings it appears to have a positive correlation with information giving and reduced anxiety levels amongst parents of hospitalized children when used appropriately. The analytical components of the concept were examined carefully and it appeared that the tool used to analyse the concept was successful in that the theoretical framework was directly related to practice, however, the framework also highlighted the delicate nature of the concept and the dangers of inappropriate use. The paper argues, however, that humour does play a part in the delivery of skilled, sensitive and competent care and the need for nurse education to address this is paramount.

Child↗

Unpacking the concept of patient satisfaction: a feminist analysis.

AIM: The aim of this paper is to present a feminist critique of the concept of patient satisfaction. BACKGROUND: Fiscal restraint, health care restructuring, shifting demographics, biomedical technological advances, and a significant shortage of health care professionals are stretching health care systems across North America to the breaking point. A simultaneous focus on consumerism and health service accountability is placing additional pressure on the system. The concept of patient satisfaction, with roots in the consumer movement of the 1960s, has both practical and political relevance in the current health care system and is commonly used to guide research related to consumer experiences of health care. Because the quality of health care encounters may lead to treatment-seeking delays, patient satisfaction research may be an effective vehicle for addressing this public health issue. However, there is wide agreement that patient satisfaction is an under-theorized concept. Using current conceptualizations of patient satisfaction, we end up all too often producing a checklist approach to 'achieving' patient satisfaction, rather than developing an understanding of the larger issues underlying individual experiences of health care. We focus on the symptoms rather than the problems. DISCUSSION: Without further theoretical refinement, the results of research into patient satisfaction are of limited use. To push forward theoretical development we might apply a variety of theoretical lenses to the analysis of both the concept and the results of patient satisfaction research. Feminism, in particular, offers a perspective that may provoke further refinement of patient satisfaction as a concept. CONCLUSIONS: Without a deeper understanding of the values and beliefs (or the worldview) that informs our approaches to researching patient satisfaction, researchers will be reacting to the most obvious indicators and failing to address the underlying issues related to individual experiences of health care.

Appointments and Schedules↗