Explainer Science News 07.08.13

This week, some research news for the Explainer team at the Science Museum – encompassing research from the whole of July, 2013.

Stem cell news

To start, three stories about stem cells, cells that have the potential to turn into any cell in the body, have caught my eye in recent months. Stem cells are hugely important in research from medicine to fundamental science. However, some of the limitations in their use arise from difficulties getting the stem cells in the first place: in the embryo in the moments after the egg has been fertilised by the sperm (embryonic stem cells); in special regions or ‘niches’ of the adult body (adult stem cells); or in small numbers by reprogramming adult tissue back to its default state within the laboratory (induced Pluripotent Stem Cells, iPS).

Our first story comes from Peking University where last month researchers made a breakthrough in the generation of these cells. Reprogrammed cells have several ethical and medical advantages over embryonic stem cells but have been confined to lab use. Until this study, reprogramming cells could only be accomplished using a number of gene factors which often resulted in unstable cells. The breakthrough made by the Peking University researchers was in reprogramming cells using a cocktail of molecules alone – a much safer and more clinically applicable technique. The group was able to reprogramme 0.2% of adult cells, a low number but comparable to those from standard iPS production techniques, suggesting this molecule approach could be the future for iPS cell research and application.

One the topic of reprogrammed cells, a group from Yokohama City University have used iPS cells to create new functioning tissue for transplantation. By mixing liver precursor cells, (cells on their way to becoming liver cells but not quite there) with cells important for the development of the human liver, they were able to form small, 3D, liver buds – the building blocks of the mature liver. The group showed that these “miniature livers” worked by implanting them into mice: the recipient mice were able to process drugs that only human livers could handle. Unfortunately, the mechanism is not entirely clear and the efficiency of the technique is low, but the potential for this kind of procedure is very large.

Finally, an exciting, though unpublished as yet, breakthrough in stem cell treatment and HIV. Two men with HIV may have been cured after they received stem-cell transplants to treat the blood cancer lymphoma. The transplants were given to replace the bone marrow, which produces our blood cells. Three and five years after treatment, these two men have no trace of HIV DNA or RNA and have been off HIV medication for 15 and seven weeks respectively. The mechanism is not fully understood but it is thought that the transplanted cells were protected from infection by the anti-retroviral drugs taken during cancer treatment. The donated cells may have killed and replaced the patient’s own cells, wiping out the patients’ HIV reservoirs. Unfortunately, this breakthrough has to be treated with some caution; these patients now have to take immune-suppressants to take care of the donated cells meaning that the treatment may be too risky for most people infected by the virus.

Tar drop experiment finally caught on film

An historical experiment akin to watching paint dry has been captured on film at last:

The tar drop experiment, testing the viscosity and stickiness of pitch, has been running for 69 years in Trinity College, Dublin. The team at Trinity College used this experiment and the footage to demonstrate that pitch is 2 million times more viscous than honey – so viscous that drops fall every 7 to 13 years. A similar experiment in the University of Queensland Australia missed filming its latest drop in 2000 because the camera was offline at the time. They have another chance this year which you can watch: http://smp.uq.edu.au/content/pitch-drop-experiment.

Solving the beehive hexagon mystery

Another long standing question was solved last month. The hexagonal structure of the honeycomb uses the least wax for the most area, something that has been pondered on since 4 B.C. Researchers from Cardiff and Peking universities have worked out how the honeycombs made by bees have more to do with fundamental physics than the wise work of the bee. The scientists observed how the bees use their body heat to melt the wax and lay down circular, not hexagonal, cells. Over time, surface tension pulls these cells into their familiar hexagonal shape – in an analogous way to the formation of hexagonal foams when bubbles are packed in a single layer.

Bonus news

Featured research and sources

Hou et al., 2013,Pluripotent Stem Cells Induced from Mouse Somatic Cells by Small-Molecule Compounds, Science – freely available at ResearchGate here. News story at Nature news

Takebe et al., Vascularized and functional human liver from an iPSC-derived organ bud transplant, Nature. News story at Science news

HIV progress story at Nature news

Tar drop captured at Nature news

Karihaloo et al., 2013, Honeybee combs: how the circular cells transform into rounded hexagons, J R Soc Interface. News story at Nature news


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