Stem Cells + Lasers = Teeth!

A group of researchers from Harvard has recently accomplished to regrow rat teeth using a laser and stem cells. They used a low-power laser to coax stem cells into growing dentin. This could have major impacts on the future of dentistry and also offer new possibilities in wound healing and bone restoration.

Biologically active molecules, called growth factors, trigger stem cells to differentiate into specialized cells. If different growth factors are introduced, different cell types will form. In order to grow tissue from stem cells, scientists usually have to extract stem cells from the body, genetically modify them in a lab and reintroduce them to the body. The new laser-technique would be non-invasive and much faster and more efficient.
“Our treatment modality does not introduce anything new to the body, and lasers are routinely used in medicine and dentistry, so the barriers to clinical translation are low,” said David Mooney, leader of the research team.

The team set up a mini-dentist office and drilled holes into the molars of rats to simulate human tooth decay. Human stem cells were introduced to the pulp and a low-light laser was applied to stimulate the growth factors. Then, the teeth were sealed with temporary caps for three months. After three months, x-rays were taken and the scientists found that the dentin had regrown due to the laser and the stem cells.

Now the Harvard team want to take their work to human clinical trials. They are currently working with one of the National Institutes of Health in the USA to outline the necessary safety and efficacy parameters.

Sources:
http://www.seas.harvard.edu/news/2014/05/researchers-use-light-to-coax-stem-cells-to-repair-teeth
http://www.iflscience.com/health-and-medicine/scientists-use-lasers-regrow-teeth-stem-cells
http://stm.sciencemag.org/content/6/238/238ra69

How Instant Photography Works

Traditional slide films used in photography consist of a plastic base that is coated with a layer of light-sensitive silver compound. Color films use three layers: one is sensitive to red light, one to blue light, and one to green light. When the film is exposed to light, each layer forms metallic silver when met with light of the right color, e.g. the green-sensitive layer forms metallic silver when exposed to green light reflected from a green shirt. Therefore, a chemical record of light and color patterns is produced. In order to get a picture from from this, a series of chemical baths containing dye developers and dye couplers has to be applied.

The paper used in instant photography consists of the same layers as traditional slide films, but there are additional layers containing all the chemicals needed for the development of the picture. The base layer is black and on top of it sit the different color layers. Under each color layer there is a developer layer with dye coupler. On the very top sit the image layer, the timing layer, and the acid layer.

A critical part for the chemical process, during which the picture will be developed, is the reagent. It consists of opacifier, alkali, and other chemical substances and is located between the light-sensitive layers and the image layer. The reagent is kept in a blob at the very edge of the plastic sheet of the paper, so the light-sensitive layers will not start to develop before they have been exposed. After taking a picture with an instant camera, the paper will come out of the camera. In doing so, it passes rollers that spread the reagent over the plastic sheet which starts the development process. As the reagent chemicals move downwards, they create metallic silver from exposed particles in each layers. The reagent also dissolves the dye couplers which then start to move towards the image layer. Metallic silver stops the dye from travelling up, therefore only dye from underneath of unexposed layers can make it to the image layer to create the picture. Meanwhile, the opacifiers and alkali in the reagent react with the acid layer of the paper. As a result, the opacifiers become clear, which makes the image visible. The timing layer is used to slow down the opacifiers and alkali, so the opacifiers will not turn clear before the image is fully developed underneath.
As soon as the opacifiers are clear, you can view your photograph!

Cancer "Stem Cells" Confirmed

The existence of cancer "stem cells" has been reported before, but due to unreliable testing methods it has never been scientifically confirmed.

In a recent study, conducted by researchers from the University of Oxford and Swedish researchers, malignant bone marrow cells of participants who suffer from myelodysplastic syndrome (MDS) were extracted. MDS is a disease that often develops into leukemia.
The growth of the extracted cells was monitored by the researchers and using genetic tools they were able to identify a rare subset of the malignant cells that sat atop the cell hierarchy. These cells encouraged other cells to mutate and form cancer and in contrast to other mutated cells they were able sustain themselves. In short, without these cancer stem cells, the other cancer cells could not survive.

This discovery offers the prospect of new cancer therapies that target the cancer stem cells exclusively. Dr Petter Woll, the first author of the study, compared the process to tending a garden: "It's like having dandelions in your lawn. You can pull out as many as you want, but if you don't get the roots they'll come back."

However, the development of a therapy that specifically targets cancer stem cells will take a lot of time. Now that researchers have found a way to identify the stem cells, they can begin to study how they actually function. Only then the development of a drug or other form of therapy can start which will also have to go through clinical trials before it can be approved for general use. Dr Woll also cautions that the stem cells of other cancer types are likely to look and function differently from the MDS cancer cells and therefore require additional research.

Sources:
http://www.ox.ac.uk/news/2014-05-16-genetic-tracking-identifies-cancer-stem-cells-patients
http://www.iflscience.com/health-and-medicine/mutations-cancer-%E2%80%98stem-cells%E2%80%99-tracked-first-time
http://www.sciencedirect.com/science/article/pii/S1535610814001342

Cardiac Disease Model Based on Stem Cells

Barth syndrome is a rare and currently untreatable cardiac disease. It affects the heart and the sceletal muscles and because it is linked to a mutation of a gene in the X-chromosome patients suffering from it are mostly male (since females have two X-chromosomes, both of them would have to carry the mutation to cause the disease in women).

A team of American scientists took skin cells of two Barth syndrome patients and converted them into induced pluripotent stem cells that carried the mutation of the gene called TAZ. These stem cells were then placed on a chip carrying biochemical support where they grew to form diseased heart tissue.

In order to confirm that the disease causes weak heart contractions the scientists used genome editing to modify the TAZ of normal cells. The TAZ product was then delivered to the diseased tissue which corrected the defect in heart contraction.

Why is this important?
This is the first tissue-based model that shows how a rare heart disease can be corrected. The knowledge derived from this model can help to develop drugs that could cure inherited cardiac diseases.

Sources:
http://www.seas.harvard.edu/news/2014/05/heart-disease-on-chip-advances-tissue-engineering
http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3545.html
http://www.iflscience.com/health-and-medicine/heart-disease-chip

Stem Cell-Based Cure for MS Found?

Multiple Sclerosis (MS) is a degenerative disease of the nervous system. It causes a loss of myelin, the insulating material that surrounds neurons and is essential for carrying electrical impulses to the brain. Over 2.3 million people worldwide suffer from MS. Currently, there is no cure nor a therapy that has proven to be effective in the long run.

In a recent study, scientists from Utah and California altered the central nervous system of mice, so they would develop a MS-like condition. Later, human neuron precursor cells that had been derived from human embryonic stem cells were injected into the spinal cords of the mice. After only two weeks, the mice had started quite drastic clinical recovery and were able to walk again, which the disease had prevented them from doing before. Furthermore, the mice recovered 73 % of their motor skills and this improvement could be sustained for six months. An examination of some of the mice's spinal cords showed that inflammation and demyelination caused by the MS-like condition had decreased significantly.

While the injected stem cells were actually rejected by the mice's bodies they still caused the desired effects. This led the scientists to the conclusion that the alleviation was likely triggered by certain chemical signals induced by the injected cells. Now the scientists are hoping to isolate these chemical signals and to put them in a drug in order to make administering the therapy easier.

Sources:
http://www.newswise.com/articles/mice-with-ms-like-condition-walk-again-after-stem-cell-treatment
http://www.iflscience.com/health-and-medicine/stem-cell-therapy-allows-mice-ms-condition-walk-again
http://www.cell.com/stem-cell-reports/abstract/S2213-6711(14)00112-X?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS221367111400112X%3Fshowall%3Dtrue?_returnURL=http%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS221367111400112X%3Fshowall%3Dtrue

How to Travel Back in Time and Shoot Hitler

This is an easily understandable manual that will explain to you how to travel back in time and kill Hitler. By doing this, you will (perhaps) be able to prevent the Holocaust and WWII!

What you will need:

• time machine
• gun

How long it will take you:

• depends entirely on you

Instructions:

1. Acquire a functioning time machine

2. Acquire a gun of your preference (we recommend semi-automatic or automatic)

3. Choose an appropriate killing-time (e.g. during a speech → not appropriate)

4. Choose an appropriate location where the assassination will take place (or took place??)

5. Set your time machine to the desired time and location

6. Travel through time and space (don’t forget to bring your gun!)

7. Find Hitler

8. If he is alone, shoot him.

9. If he is not alone, assess the situation and decide if the other people present pose a threat to you or you mission.

10. If they do, shoot them too. We recommend you be quick about it while they are still surprised.

11. If they do not pose a threat, proceed to shoot Hitler and let the others live.

12. Travel back home and reward yourself with a drink.

Congratulation, you have just saved millions of lives and prevented a bloody war!

Camera Lucida Instructions

Our group agreed that the instruction is helpful, yet there were several things that would need improvement to turn this into a good instruction sheet. First of all, there should be a short explanation on what a camera lucida actually is and what it can be used for. At the top, a list of all the materials needed to build the camera would be useful, otherwise people who start reading the text before having a close look at the pictures might encounter problems. Moreover, the units of length are illegible, therefore it is hard to find out if the author meant centimeters, millimeters, or a completely different unit. Another thing our group would change is the structure of the two paragraphs as we would rather use bullet points to describe the building process. While we think that the pictures are very helpful and that the author obviously put a lot of effort into these instructions, we are convinced that the individual steps could be structured better.