• All articles except case reports must have a structured abstract that states in 250 words or fewer the purpose, basic procedures, main findings, and principal conclusions of the study.
• Divide the abstract with the headings Aim, Methods, Results, Conclusions.
• The title of the article should be described at the top of the abstract.
• The abstract should not contain abbreviations or references.
• Five keywords (for the purposes of indexing) should be supplied below the abstract, in alphabetical order, and should be taken from those recommended by the US National Library of Medicine's Medical Subject Headings (MeSH) browser list.

Authors should use subheadings to divide the sections of their manuscript: Introduction, Methods, Results, Discussion, Acknowledgments, Disclosure, References.

The source of financial grants and other funding should be acknowledged, including a frank declaration of the authors' industrial links and affiliations. The contribution of colleagues or institutions should also be acknowledged. Thanks to anonymous reviewers are not allowed.

At the time of submission, the Corresponding author must include a disclosure statement in the body of the manuscript. The statement will describe all of the authors' relationships with the companies that may have a financial interest in the information contained in the manuscript. This information should be provided under the heading titled 'Disclosure' which should appear after the 'Acknowledgements' section and before the 'References' section. The absence of any interest to disclose must also be stated.

Tables should be self-contained and complement, but not duplicate, the information contained in the text. Tables should be numbered consecutively in Arabic numerals. Each table should be presented with a comprehensive but concise legend. Tables should be double-spaced and vertical lines should not be used to separate columns. Column headings should be brief, with units of measurement in parentheses; all abbreviations should be defined in footnotes. Footnote symbols: †, ‡, §, ¶, should be used (in that order) and *, **, *** should be reserved for P-values. Statistical measures such as SD or SEM should be identified in the headings. The table and its legend/footnotes should be understandable without reference to the text.

All illustrations (line drawings and photographs) are classified as figures. Figures should be cited in consecutive order in the text. Line figures should be supplied as sharp, black and white graphs or diagrams, drawn professionally or with a computer graphics package; lettering should be included. Individual images forming a composite figure should be of equal contrast, to facilitate printing, and should be accurately squared. Images need to be cropped sufficiently to prevent the subject from being recognized, or an eye bar used. Magnifications should be indicated using a scale bar on the illustration. Images should be supplied as high resolution (at least 300 d.p.i.) files, saved in .eps or .tif format. Digital images supplied only as low-resolution print-outs and/or files cannot be used.