Why elephants rarely get cancer?

Elephants have 38 additional modified copies (alleles) of a gene that encodes p53, a well-defined tumor suppressor, as compared to humans, who have only two. Further, elephants may have a more robust mechanism for killing damaged cells that are at risk for becoming cancerous. In isolated elephant cells, this activity is doubled compared to healthy human cells, and five times that of cells from patients with Li-Fraumeni Syndrome, who have only one working copy of p53 and more than a 90 percent lifetime cancer risk in children and adults. The results suggest extra p53 could explain elephants' enhanced resistance to cancer. The scientists combed through the African elephant genome and found at least 40 copies of genes that code for p53, a protein well known for its cancer-inhibiting properties. DNA analysis provides clues as to why elephants have so many copies, a substantial increase over the two found in humans. The vast majority, 38 of them, are so-called retrogenes, modified duplicates that have been churned out over evolutionary time.

hey extracted white blood cells from blood drawn from the animals during routine wellness checks and subjected the cells to treatments that damage DNA, a cancer trigger. In response, the cells reacted to damage with a characteristic p53-mediated response: they committed suicide. Schiffman says, "If you kill the damaged cell, it's gone, and it can't turn into cancer. This may be more effective of an approach to cancer prevention than trying to stop a mutated cell from dividing and not being able to completely repair itself."

To test this, the researchers did a side-by-side comparison with cells isolated from elephants (n=8), healthy humans (n=10), and from patients with Li-Fraumeni Syndrome (n=10). They found that elephant cells exposed to radiation self-destruct at twice the rate of healthy human cells and more than five times the rate of Li-Fraumeni cells (14.6%, 7.2%, and 2.7%, respectively). These findings support the idea that more p53 offers additional protection against cancer.

Ref: Joshua D. Schiffman, MD et al. (2015) Potential mechanisms for cancer resistance in elephants and comparative cellular response to DNA damage in humans. JAMA.

DOI: 10.1001/jama.2015.13134

and female brain differences negligible

Meta-analysis of structural MRI volumes that found no significant difference in hippocampal size between men and women. Meta-analysis is a statistical technique that allows researchers to combine the findings from many independent studies into a comprehensive review. Hippocampi are located on both sides of the brain, under the cerebral cortex. The team's findings challenge the common claim that a disproportionately larger hippocampus explains females' tendency toward greater emotional expressiveness, stronger interpersonal skills, and better verbal memory."Many people believe there is such a thing as a 'male brain' and a 'female brain,'" Dr. Eliot said. "But when you look beyond the popularized studies at collections of all the data you often find that the differences are minimal."

Meta-analyses by other investigators have also disproved other purported sex differences in the brain, Dr. Eliot noted. There is no difference in the size of the corpus callosum, white matter that allows the two sides of the brain to communicate, nor do men and women differ in the way their left and right hemispheres process language.

Ref: Anh Tan, Wenli Ma, Amit Vira, Dhruv Marwha, Lise Eliot. The human hippocampus is not sexually-dimorphic: Meta-analysis of structural MRI volumes. NeuroImage, 2016; 124: 350

DOI:10.1016/j.neuroimage.2015.08.050

ITOP: A 3D bioprinter can produce human body parts

Scientists have transplanted living tissue constructed by a sophisticated and improved 3D printer. A challenge for tissue engineering is producing three-dimensional (3D), vascularized cellular constructs of clinically relevant size, shape and structural integrity. An integrated tissue–organ printer (ITOP) that can fabricate stable, human-scale tissue constructs of any shape. Mechanical stability is achieved by printing cell-laden hydrogels together with biodegradable polymers in integrated patterns and anchored on sacrificial hydrogels. The correct shape of the tissue construct is achieved by representing clinical imaging data as a computer model of the anatomical defect and translating the model into a program that controls the motions of the printer nozzles, which dispense cells to discrete locations. The incorporation of microchannels into the tissue constructs facilitates diffusion of nutrients to printed cells, thereby overcoming the diffusion limit of 100–200 μm for cell survival in engineered tissues. Future development of the ITOP is being directed to the production of tissues for human applications and to the building of more complex tissues and solid organs.

Ref: Hyun-Wook Kang et al., A 3D bioprinting system to produce human-scale tissue constructs with structural integrity, Nature Biotechnology (2016).

Doi:10.1038/nbt.3413

Workaholism linked to psychiatric disorders

Workaholism frequently co-occurs with Attention deficit hyperactivity disorder (ADHD), Obsessive–compulsive disorder (OCD), anxiety, and depression.

Workaholics score higher on all clinical states

The study showed that workaholics scored higher on all the psychiatric symptoms than non-workaholics. Among workaholics, the main findings were that:

• 32.7 per cent met ADHD criteria (12.7 per cent among non-workaholics).
• 25.6 per cent OCD criteria (8.7 per cent among non-workaholics).
• 33.8 per cent met anxiety criteria (11.9 per cent among non-workaholics).
• 8.9 per cent met depression criteria (2.6 per cent among non-workaholics).
  
  
  Seven diagnostic criteria for workaholism

• You think of how you can free up more time to work.
• You spend much more time working than initially intended.
• You work in order to reduce feelings of guilt, anxiety, helplessness or depression.
• You have been told by others to cut down on work without listening to them.
• You become stressed if you are prohibited from working.
• You deprioritize hobbies, leisure activities, and/or exercise because of your work.
• You work so much that it has negatively influenced your health.

Scoring 1 (never) 4 (often) or 5 (always) - four or more criteria identify a workaholic.

These findings highlight the importance of further investigating neurobiological deviations related to workaholic behaviour.

Ref: Cecilie Schou Andreassen et al, The Relationships between Workaholism and Symptoms of Psychiatric Disorders: A Large-Scale Cross-Sectional Study. PLOS ONE, 2016; 11 (5): e0152978.

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Nano rod and worm are the best shaped nanoparticles in cancer drug delivery

Micrographs of shapes of Nanoparticles (a) Spheres. (b) Rectangular disks. (c) Rods. (d) Worms. (e) Oblate ellipses. (f) Elliptical disks. (g) UFOs. (h) Circular disks. (Scale bars: 2 μm.). Image courtesy (Champion JA, Katare YK, Mitragotri S.)

Nanoparticle research is currently an area of intense scientific research, due to a wide variety of potential applications in biomedical, optical, and electronic fields. For the first time, researchers have found that nanoparticles shaped like rods and worms are far more effective at travelling through cells and specific barriers like the nucleus than spherical ones.  The team applied a new fluorescent microscopy method to standard drug delivery, which allowed them to track the movement of nanoparticles of different shapes through a single cancer cell. When the researchers used doxorubicin (a cancer drug) in the different shaped nanoparticles, the rod and worms passively entered the nucleus without any issues. The spherical ones, on the other hand, were stuck outside the nucleus. Getting through the nuclear membrane and into the nucleus is important for increasing the toxicity of cancer cells, so rods and worms came out on top. Now, it can help to reduce some side effects of chemotherapies and it gives the ability to look inside the cell, see what the particles are doing, and design them to do exactly what we want them to do.

Ref: Elizabeth Hinde et al, 2016. Pair correlation microscopy reveals the role of nanoparticle shape in intracellular transport and site of drug release. Nature Nanotechnology.

Doi: 10.1038/nnano.2016.160