The misinterpretation of study results based on statistical significance.
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Biomarkers, Tumor↗
Biomedical subjects
A Stang
Publications and source records attributed to A Stang.
Control response proportions in population-based case-control studies in Germany.
We investigated the methods of recruitment, levels and determinants of response, and the calculation method of response proportions in population-based case-control studies in Germany. We identified 26 eligible studies. The pooled analysis showed that the response proportion was 68% among controls and 80% among cases. Response proportions among controls without telephones were about 50% lower than for controls with telephones. We propose a new measure that indicates the efficacy of the recruitment strategy.
Adult↗
Expression of connexin43 mRNA in adult rodent brain.
The expression of connexin43 mRNA was detected in adult rat brains by in situ hybridization methods. Specific digoxigenin riboprobes were generated by in vitro transcription of two PCR-amplified fragments of connexin43 cDNA which lack homology with any other published connexin. Following immunohistochemical detection, the digoxigenin cRNA was found to occur in various neuronal populations including Purkinje cells of the cerebellum, pyramidal cells of the neocortex and the hippocampal formation, as well as granule cells of the dentate gyrus and various neurons of diverse hindbrain nuclei. This ubiquituous expression of connexin43 mRNA in adult neurons, in particular in neocortical pyramidal cells, is surprising insofar as gap junction communication in adult bains has been considered to be confined to specific subpopulations of neurons revealing a high incidence of synchronized electrical activities in contrast to the postnatal brain where interneuronal coupling via gap junctions precedes the formation of chemical transmission. In addition, connexin43 is regarded as being preferentially expressed in astrocytes, although its presence in adult neurons has not definitely been excluded. We propose that adult neurons preserve their capability of expressing functional gap junctions more frequently than presently considered and that connexin43 is a most likely neuronal gap junction protein candidate.
Animals↗
Elevated lipoprotein(a) levels in patients with acute myeloblastic leukaemia decrease after successful chemotherapeutic treatment.
Twenty-two patients with acute myeloblastic leukaemia (AML) were studied to investigate disease-associated changes in lipid metabolism. Lipoprotein (a) [Lp(a)] levels were found to be elevated at the time of diagnosis (median 23 mg/dl; 41% of patient group had levels greater than 25 mg/dl) and diminished after successful chemotherapeutic treatment in 9 of 10 cases, with a maximum decrease from 56 to 10 mg/dl. In contrast, reduced levels of total cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL) (medians 137, 87 and 20 mg/dl, respectively) were observed at the time of diagnosis. Cholesterol and HDL levels increased in all 10 and LDL in 9 cases in which complete remission was achieved. These data suggest that the catabolism of LDL-cholesterol might be even more enhanced than assumed to date. Furthermore, it indicates that the Lp(a) level in acute myeloblastic leukaemia is influenced either directly or indirectly by the leukaemic blasts.
Adult↗
Retransplantation of an already transplanted heart.
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Adult↗
[Changes in cell differentiation in vitro by inducing drug resistance].
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Cell Differentiation↗
[Important prognostic factors for the results of physiotherapeutic exercises in intermittent claudication (author's transl)].
In 240 patients with peripheral circulatory disorders (Fontaine Stage II) who had participated in intensive physiotherapeutic interval training daily for 6 weeks between October 1974 and July 1976, it was established that the therapeutic results were not related to age or sex. The "risk" factors of smoking, diabetes mellitus, hypertriglyceridemia, hypercholesterolemia and hyperuricemia individually show no connection with the results. Only overweight, hypertension and coronary heart disease appear to have an unfavorable influence. It is distinctly recognizable that the more risk factors there are combined in a patient with intermittent claudication, the less chance he has of success in physiotherapeutic vessel training.
Aged↗
[The problem of response in epidemiologic studies in Germany (Part II)].
The first part of this paper introduced various definitions of response and discussed their significance in the context of different study types. This second part addresses incentives as a method to increase response and evaluates the impact of non response or delayed response on the validity of the study results. Recruitment aims at minimising the proportion of refusal. To achieve this, incentives can be used and potential participants can be contacted in a sequence of increasing intensity. The effectiveness of different incentives was investigated within the pretest of the German survey on children and adolescents by the Robert Koch Institute. A low response is often interpreted in terms of non-response bias. This assumption, however, is as incorrect as would be opposite conclusion, that a high response guarantees valid results. Any study of the influence of nonresponse requires information on non-responders. The comparison between early and late responders as an indirect method to evaluate systematic differences between participants and non-participants by wave analysis is demonstrated within the Northern Germany Leukaemia and Lymphoma study (NLL). The German guidelines for Good Epidemiologic Practice recommend to solicit a minimum of information on the principal hypotheses of a study from non-participants. The example of a population-based health survey (Cooperative Health Research in the Region of Augsburg, KORA) illustrates how information on non-responders within a quantitative non-responder analysis can be achieved and used for the estimation of prevalences. Recommendations how to deal with the response in epidemiological studies in Germany are suggested.
Adolescent↗
One heart transplanted successfully twice.
We report the first successful reuse of a previously transplanted heart after perioperative brain death of the first recipient. The second recipient was a 66-year-old man suffering from end-stage ischemic cardiomyopathy. The intra- and postoperative course of the retransplantation was completely uneventful. At the time of writing, more than 2 years after reuse of the graft, the patient remains in New York Heart Association class I. This procedure, which proved to be possible under certain optimal conditions, should be considered in the case of brain death of a graft recipient, particularly with regard to the ongoing donor shortage.
Adult↗