Discussion sections in reports of controlled trials published in general medical journals.

Context: Reliable interpretation of the results of a controlled trial entails setting its results in the context of similar research. A previous study showed that most reports of controlled trials published in 5 general medical journals in May 1997 were deficient in this respect. We assessed the extent to which reports of controlled trials published in the same 5 journals discussed new results in light of the totality of evidence from other controlled trials.

A brief history of research synthesis.

Science is supposed to be cumulative, but scientists only rarely cumulate evidence scientifically. This means that users of research evidence have to cope with a plethora of reports of individual studies with no systematic attempt made to present new results in the context of similar studies. Although the need to synthesize research evidence has been recognized for well over two centuries, explicit methods for this form of research were not developed until the 20th century.

Why we need to know whether prophylactic antibiotics can reduce measles-related morbidity.

In some parts of the world, measles vaccination has resulted in very substantial reductions in measles-related morbidity and mortality. Even so, it has been estimated that 30 million people still contract the disease every year, that nearly 1 million of these die, and that measles-related deaths account for about 10% of all deaths in children under the age of 5 in developing countries. Existing evidence from controlled trials suggests that antibiotic prophylaxis in measles can result in important reductions in measles-related morbidity, and, at a World Health Organization meeting convened in 1993 to decide on research priorities for the treatment of measles, highest priority was accorded to additional controlled trials of prophylactic antibiotics.

Current Controlled Trials: an opportunity to help improve the quality of clinical research.

Some problems with the quality of controlled clinical trials can be addressed by following these procedures: registering all trials at inception; using systematic reviews to inform the design of new studies; posting and obtaining feedback on preprints; reporting all well conducted trials, regardless of their results; reducing biased and inefficient assessment of reports submitted for publication; publishing sufficiently detailed reports; linking trial reports to relevant external information; providing readier access to reports; and reviewing and amending reports after initial publication. The launch of a new range of electronic journals by Current Controlled Trials offers an opportunity to contribute to progress in these ways.

Comparing like with like: some historical milestones in the evolution of methods to create unbiased comparison groups in therapeutic experiments.

Histories of clinical trials have recorded and analysed the development of quantification in therapeutic evaluation, the emergence of probabilistic thinking, the application of statistical methods and theory, and the sociology, ethics and politics of clinical trials; but it is surprising that they only rarely identify as a distinct theme the development of efforts to control biases. An exception is Kaptchuk's recent account of the history of blinding and placebos for reducing observer biases. In this complementary paper I introduce and discuss some milestones between 1662 and 1948 in the development of methods to control selection biases when assembling therapeutic comparison groups, to ensure, as far as possible, that 'like is compared with like'.

A randomized, controlled trial of methotrexate versus placebo in early diffuse scleroderma.

Objective: Early diffuse scleroderma (systemic sclerosis; SSc) has no proven treatment. This study was undertaken to examine the efficacy of methotrexate (MTX) in improving the skin and other disease parameters in early diffuse SSc.

Methods: Seventy-one patients with diffuse SSc of <3 years' duration were enrolled in a multicenter, randomized, placebo-controlled, double-blind trial.

Characterization of the human Xq21.3/Yp11 homology block and conservation of organization in primates.

The Xq21.3/Yp11 homology block on the human sex chromosomes represents a recent addition to the Y chromosome through a transposition event. It is believed that this transfer of material occurred after the divergence of the hominid lineage from other great apes.

Mapping the chromosome 16 cadherin gene cluster to a minimal deleted region in ductal breast cancer.

The cadherin family of cell adhesion molecules has been implicated in tumor metastasis and progression. Eight family members have been mapped to the long arm of chromosome 16. Using radiation hybrid mapping, we have located six of these genes within a cluster at 16q21-q22.