Estimates of the annual number of clinically recognized pregnancies in the United States, 1981-1991.

The authors estimated the number of clinically recognized pregnancies that occurred annually from 1981 to 1991 in the United States by type of outcome and by race. Estimates of the numbers of livebirths, induced abortions, ectopic pregnancies, and fetal deaths were obtained by using data from the Centers for Disease Control and Prevention in Atlanta, Georgia. The number of spontaneous abortions was estimated by using previously published, age-specific rates. More than 67 million pregnancies occurred during the study period. Overall, 62.5% of these pregnancies resulted in livebirths, 21.9% in legal induced abortions, 13.8% in spontaneous abortions, 1.3% in ectopic pregnancies, and 0.5% in fetal deaths. These data can be used to provide denominators for the calculation of a variety of pregnancy outcome-specific rates.     

The contextual nature of medical information

Successful design of information systems in health care starts with a thorough understanding of the practices in which the systems are to function. In this paper, we discuss the nature of 'medical information' from a sociological perspective. We focus on the (im)possibilities of the utilization of primary health care data for secondary purposes such as research and administration. In much of the literature on EPRs, this secondary utilization is only seen to depend on the question whether the IT connections are in place. It is then simply a matter of selecting which information to transport and to where. In this article, we argue that this view of medical information is mistaken. Information should be conceptualized as always entangled with the context of its production. The disentangling of information from its production context is possible, but that entails work. We propose the following 'law of medical information': the further information has to be able to circulate (i.e. the more diverse contexts it has to be usable in), the more work is required to disentangle the information from the context of its production. The question that then becomes pertinent is; who has to do this work, and who reaps the benefits?     

Influence of serum albumin on renal function in nephrotic syndrome

 Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), determined by the clearances of inulin and para-aminohippuric acid, were evaluated in 119 children with different types of nephrotic syndrome and in different stages: the nephrotic stage (serum albumin <25 g/l), recovery stage (25–35 g/l), and remission (>35 g/l). GFR in the nephrotic stage was significantly lower than in remission and in controls, and was lowest at onset of the disease (84±6, 111±4, and 119±2 ml/min per 1.73 m²). ERPF was higher in the nephrotic stage than in recovery, especially in children with histological lesions. Thus the filtration fraction (FF) was greatly decreased in the nephrotic stage. In patients investigated both in the nephrotic and the remission phase, GFR and FF increased significantly. There was a direct correlation between the serum albumin concentration and FF and an inverse correlation between mean arterial pressure (MAP) and GFR and FF in all patients, a direct correlation between the serum albumin concentration and GFR in minimal change nephrotic syndrome patients, and an inverse correlation between ERPF and serum albumin in children with histological lesions. In conclusion, GFR and FF were decreased and ERPF increased in the nephrotic stage, normalizing in remission. The low GFR in the nephrotic stage was thus not dependent on hypoperfusion. We suggest that the low GFR is dependent on a very low ultrafiltration coefficient. The direct correlation between GFR and serum albumin and the indirect correlation between GFR and MAP suggest compensatory mechanisms that increase the ultrafiltration pressure to counteract the severely reduced ultrafiltration coefficient. Received: 19 November 1997 / Revised: 11 April 1998 / Accepted: 14 April 1998     

Classification of childhood epilepsy syndromes in newly diagnosed epilepsy: interrater agreement and reasons for disagreement

PURPOSE: The International League Against Epilepsy (ILAE) classification of the epilepsies is in increasingly widespread use. The following analysis was done to assess the interrater agreement in classifying epilepsy syndromes in children with newly diagnosed epilepsy. METHODS: In a prospective, community-based study, 613 children with newly diagnosed epilepsy were recruited. Based on information available at diagnosis or generated as part of the initial diagnostic assessment, three pediatric neurologists independently classified epilepsy syndromes. Interrater agreement was assessed with kappa. RESULTS: Interrater agreement was extremely good, with kappa scores > or = 0.80 for almost all comparisons. Relatively limited quality of the EEG and seizure information in some cases, as well as discrepancies between the two, were associated with a tendency for more disagreement. CONCLUSIONS: A high degree of interrater agreement was obtained in this study, indicating that the system for classifying syndromes can be meaningfully used in a community-based sample. Quality of the information, which is often, by necessity, less than optimal in newly diagnosed epilepsy, is a potential barrier to identification of syndromes. A substantial proportion of children were classified into relatively nonspecific syndromes. Over time, additional information may come to light to allow more precise identification of their forms of epilepsy. In an epidemiologic setting, the ILAE classification of the epilepsies can be successfully used with a high degree of reliability to classify newly diagnosed epilepsy in children.     

Topography of the auditory P300 in schizotypal personality.

BACKGROUND: Research with schizophrenic patients has demonstrated reduced amplitude of the P300b elicited with the auditory "oddball" paradigm, as well as reduced P300a amplitude following "novel" stimuli. The focus of the present study was the investigation of these components in a nonclinical sample of participants with high expressions of the schizotypal personality trait. METHODS: By use of an acoustic oddball task, including the presentation of novel stimuli, the event-related brain potentials of 14 participants with "low" and 13 participants with "high" scores on the German adaptation of the "Schizotypal Personality Questionnaire" were investigated. Current source density (CSD) curves and spline-interpolated CSD maps were generated. Peak amplitudes and latencies of the N100, P200, P300a, and P300b were determined for the CSD data. RESULTS: Results indicate no group differences with respect to N100, P200, and P300a amplitudes and latencies. By contrast, the P300b amplitude was significantly smaller in high- as compared to low-scoring participants. Left-temporal as compared to right-temporal P300b was significantly smaller in high- than in low-schizotypal participants. CONCLUSIONS: Confirming results of other researchers, this present study suggests that a reduced P300b amplitude and an altered P300b topography at temporal sites may be a trait-like "marker" of the schizophrenia spectrum.     

Gaining access to underresearched populations in women's health research

Culture is an important variable in women's health research, and sample selection must include plans to recruit participants who represent the overall cultural makeup of the population. However, gaining access to underresearched groups is a major challenge and requires specific planning. Salient access techniques utilized by epidemiological researchers include (a) obtaining the support and endorsement of community leaders, (b) advertising the research in community publications, and (c) utilizing age, gender, and culturally matched research assistants. Although these elements were included in the planning of a study of the perimenopausal transition of Filipino American midlife women, the more powerful attractors for this particular cultural group were their pride in participating in a study that was associated with a major university and their intense community service orientation. Since each cultural group has unique issues and concerns, researchers must familiarize themselves with the values of their target group and emphasize these in recruitment approaches.     

Effects of propofol (intravenous propofol emulsion) on cell membranes measured by electrofusion and electroporation

The influence of propofol (CAS 2078-54-8 (intravenous propofol emulsion) on cell membrane properties was investigated in vitro with techniques of cell electrofusion and cell electroporation. Human lymphoma cells and plant protoplasts were chosen as a model system. Propofol (intravenous propofol emulsion) decreased the electrofusion yield of the cells and their membrane permeability. A 50% decrease in relative electrofusion was observed in human lymphoma cells in the presence of about 0.05 mmol/l propofol (intravenous propofol emulsion) and in plant protoplasts in the presence of about 0.1 mmol/l. The fusion of human lymphoma cells was inhibited to 100% at concentrations higher than 0.2 mmol/l propofol and 0.4 mmol/l intravenous propofol emulsion. The membrane permeability of human lymphoma cells decreased by the factor of two with increasing propofol concentrations up to about 0.1 mmol/l. The effects of electroporation were highly reversible. Propofol (intravenous propofol emulsion) was more effective than tetracaine. These sensitive techniques are suitable for the investigation of interactions between anesthetic drugs and the cell membrane.