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Human example of incomplete dominance; myostatin-related hypertrophy.  Results in an overgrowth of muscle tissue.

In a paper this week in Science, Vogelstein and Cristian Tomasetti, who joined the biostatistics department at Hopkins in 2013, put forth a mathematical formula to explain the genesis of cancer. Here's how it works: Take the number of cells in an organ, identify what percentage of them are long-lived stem cells, and determine how many times the stem cells divide. With every division, there's a risk of a cancer-causing mutation in a daughter cell. Thus, Tomasetti and Vogelstein reasoned, the tissues that host the greatest number of stem cell divisions are those most vulnerable to cancer. When Tomasetti crunched the numbers and compared them with actual cancer statistics, he concluded that this theory explained two-thirds of all cancers.

The physical connection between mother and fetus is provided by the placenta, an organ, built of cells from both the mother and fetus, which serves as a conduit for the exchange of nutrients, gasses, and wastes. Cells may migrate through the placenta between the mother and the fetus, taking up residence in many organs of the body including the lung, thyroid, muscle, liver, heart, kidney and skin. These may have a broad range of impacts, from tissue repair and cancer prevention to sparking immune disorders.

The mouse is the leading organism for disease research. A rich resource of genetic variation occurs naturally in inbred and special strains owing to spontaneous mutations. However, one can also obtain desired gene mutations by using the following processes: targeted mutations that eliminate function in the whole organism or in a specific tissue; forward genetic screens using chemicals or transposons; or the introduction of exogenous transgenes as DNAs, bacterial artificial chromosomes (BACs) or reporter constructs. The mouse is the only mammal that provides such a rich resource of genetic diversity coupled with the potential for extensive genome manipulation, and is therefore a powerful application for modeling human disease.

Nestled in the tissues of your neck is a small, unassuming organ that wields enormous power over your body: the thyroid. Emma Bryce explains how the thyroid, like the operations manager in a company, is tasked with making sure that all the cells in your body are working properly.

The question of cell renewal is one that all of us have intuitive daily experience with. We all notice that our hair falls out regularly, yet we don't get bald (at least not until males reach a certain age!).  Similarly, we have all had the experience of cutting ourselves only to see how new cells replaced their damaged predecessors. And we donate blood or give blood samples without gradually draining our circulatory system. All of these examples point to a replacement rate of cells, that is characteristic of different tissues and in different conditions, but which makes it abundantly clear that for many cell types renewal is a part of their story.

An MRI scan showed a cluster of what appeared to be lesions in his brain, but specialists were baffled as to the cause. And they were more surprised to find that the lesions kept moving. Brain scans over the next four years showed that the anomaly had travelled at least 5cm through the tissue.

The treatment used olfactory ensheathing cells (OECs) - specialist cells that form part of the sense of smell. OECs act as pathway cells that enable nerve fibres in the olfactory system to be continually renewed. In the first of two operations, surgeons removed one of the patient's olfactory bulbs and grew the cells in culture. Two weeks later they transplanted the OECs into the spinal cord, which had been cut through in the knife attack apart from a thin strip of scar tissue on the right. They had just a drop of material to work with - about 500,000 cells.

Computed tomography (CT) is an excellent noninvasive technique to investigate bones and soft tissue structures in a patient. Unfortunately, sometimes imaging can be difficult, as any movement from the patient can result in images that are unclear and need to be redone. This is especially difficult when dealing with patients who are young children, mentally impaired, suffering from motor disease, or are in pain. To ensure these images are clear, these challenging patients may require sedation, which is not desirable. General Electronics sought to facilitate treatment of these patients and improve the imaging process in general with the development of the Revolution CT.

The worst cancer cells don't sit still. Instead they metastasize-migrate from their original sites and establish new tumors in other parts of the body. Once a cancer spreads, it is harder to eliminate. A study by developmental biologists offers a fresh clue to how cancer cells acquire the ability to invade other tissues-a prerequisite for metastasis. It reveals that invasion requires cells to stop dividing. Therefore, the two processes- invasion and proliferation-are mutually exclusive. The finding could inform cancer therapies, which typically target rapidly proliferating cancer cells.

Starfish can regrow lost arms, and salamanders can sprout new limbs. So why can't we? Sci Show explains the science of regeneration, and explores the limitations the humans face -- and are trying to go beyond.

Article summarizing cell division with time lapse cell division video of 30hours pro vs eukaryotic division.