No abstract

Ondansetron, a potent and highly selective 5-HT₃ receptor antagonist, prevents emesis following chemotherapy by antagonising the action of 5-hydroxytryptamine (5-HT) at 5-HT₃ receptors on vagal afferent neurones that innervate the gastrointestinal tract and 5-HT₃ receptors in the central vomiting system. Evidence suggests that chemotherapy induces the release of 5-HT from enterochromaffin cells in the small intestine. This stimulates vagal afferent nerves via 5-HT₃ receptors. Information is then relayed, via the vagus nerve, to the central vomiting system. 5-HT₃ receptors are also found in the hind-brain vomiting system including the area postrema (the site of the chemore-ceptor trigger zone for emesis). Therefore, following chemotherapy, 5-HT activates 5-HT₃ receptors at 2 sites to induce emesis. Clinical data showing that a single dose of ondansetron prevents acute emesis suggest that it is important to block the initiation of the emetic reflex. This may prevent the recruitment of central mechanisms involving 5-HT₃ receptors.

Reflecting on the WHO consultation on developing global norms for sharing data and results during public health emergencies, Patrick Vallance and colleagues argue that there are significant benefits to the principle of data sharing.

In May 2013, GlaxoSmithKline (980 Great West Road, Brentford, Middlesex, TW8 9GS, UK) established a new online system to enable scientific researchers to request access to anonymised patient level clinical trial data. Providing access to individual patient data collected in clinical trials enables conduct of further research that may help advance medical science or improve patient care. In turn, this helps ensure that the data provided by research participants are used to maximum effect in the creation of new knowledge and understanding. However, when providing access to individual patient data, maintaining the privacy and confidentiality of research participants is critical. This article describes the approach we have taken to prepare data for sharing with other researchers in a way that minimises risk with respect to the privacy and confidentiality of research participants, ensures compliance with current data privacy legal requirements and yet retains utility of the anonymised datasets for research purposes. We recognise that there are different possible approaches and that broad consensus is needed.

Rearrangements of chromosome band 11q23 are common in infant leukemias, comprising more than 70% of the observed chromosome abnormalities in children less than 1 year of age. The MLL gene, which is located at the 11q23 breakpoint in infant, childhood, and adult acute leukemias, has been cloned and has homology to the Drosophila trithorax gene. The breakpoints in MLL are restricted to an 8.3-kilobase pair (kb) region of the gene that is involved in translocations with as many as 29 other chromosomal regions in a number of phenotypically distinct acute leukemias. We have detected an identical, clonal, nonconstitutional rearrangement of the MLL gene in peripheral blood cells from a pair of female infants twins with acute lymphoblastic leukemia (ALL) and a t(11;19)(q23;p13.3). The detection of nonidentical IGH rearrangements suggests that the MLL rearrangement took place in a B-cell precursor or hematopoietic stem cell in one twin which was transferred in utero to the other fetus resulting in ALL with an identical aneuploid karyotype in both infants. We speculate that the other MLL-related infant leukemias may also develop in utero, and that the rearrangements may occur consistently in stem cells or early precursor cells, accounting for the frequency of mixed-lineage leukemia in infants.