Bonhoeffer et al. (Reports, 26 November 2004, p. 1547) presented evidence for positive epistasis in a clinical data set of HIV-1 mutants and corresponding fitness values. We demonstrate that biases in the original and simulated data sets may lead to erroneous evidence for epistasis. More rigorous statistical tests must be used to account for such biases before one can infer epistasis.

AIMS To investigate the prevalence of lymphocytic gastritis in patients with coeliac disease. METHODS Gastric biopsies from 70 patients with coeliac disease were examined by light microscopy for the presence of lymphocytic gastritis, defined as 25 or more intraepithelial lymphocytes/100 gastric columnar epithelial cells. RESULTS Lymphocytic gastritis was found in seven cases. Positive cases...

We compared the single-nucleotide polymorphisms (SNPs) in humans in 182 housekeeping and 148 tissue-specific genes. SNPs were divided into rare and common polymorphisms based on their frequencies. We found that housekeeping genes tend to be less polymorphic than tissue-specific genes for both rare and common SNPs. Using mouse as a second species for computing sequence divergences, we found no e...

objectives: against the background of evidence-based treatments for schizophrenia resistant to medication, the implementation of cognitive-rehabilitation therapy (crt) becomes more important, especially about patients who don’t response to medication. there is less evidence for group format and face to face structure of crt and also for resistant to medication patients. this research investigat...

This second article of the series "An Overview of Research Designs Relevant to Nursing" presents qualitative research designs. Phenomenological, ground theory, ethnography, narrative inquiry, and other related qualitative-related research methodologies are described. In addition, the importance of qualitative research as groundwork for quantitative studies is discussed. This link between qualit...

There is increasing evidence that outcomes of health care differ by patient characteristics, such as gender and ethnicity. If evidence-based medicine is to improve quality of care for all patients, it is essential to take this diversity into account when designing clinical studies. So far, this notion has mainly been translated into recommendations for including minority populations in trials. ...

BACKGROUND As the overall evidence for the effectiveness of teaching of evidence based medicine (EBM) is not strong, and the impact of cultural and societal influences on teaching method is poorly understood, we undertook a randomised-controlled trial to test the effectiveness and learning satisfaction with two different EBM teaching methods (usual teaching vs. problem based learning (PBL)) for...

This letter considers the main challenges that people with rare diseases and their families face: delay in diagnosis, lack of appropriate support and information, and impaired access to treatment. The differences in medical experience between a patient with a rare disease and one with a common one are made through the use of a real-life example: the diagnosis of leiomyosarcoma received by my mo...

BACKGROUND Previous studies report various degrees of agreement between self-perceived competence and objectively measured competence in medical students. There is still a paucity of evidence on how the two correlate in the field of Evidence Based Medicine (EBM). We undertook a cross-sectional study to evaluate the self-perceived competence in EBM of senior medical students in Malaysia, and ass...

Evidence based medicine (EBM) puts forward a hierarchy of evidence for informing therapeutic decisions. An unambiguous interpretation of how to apply EBM’s hierarchy has not been provided in the clinical literature. However, as much as an interpretation is provided proponents suggest a categorical interpretation. The categorical interpretation holds that all the results of randomised trials alw...