Thursday, November 21, 2013

Signs of Aging, Even in the Embryo

            I found this article to be very interesting.  The article proposed that cells of animals are capable of reaching old age even at the very beginning.  Scientists believed that if human cells were put in a test tube with a good amount of nutrients, the cells would multiply forever.  However, Dr. Hayflick and Dr. Moorehead discovered that this is not the case through their study of fetal human cells.  The doctors found that the fetal cells would divide up to 50 times and then stop.  Cells that stop growth in such a manner are called senescent.  Senescent cells are responsible for several aspects of old age, including wrinkled skin, cataracts, and arthritic joints.  The reason why the cells eventually stop dividing is that the DNA gradually accumulates damage, and switches on a set of genes that cease all growth once the DNA becomes too damaged.  Such senescent cells were found in embryos of mice, which is interesting because “the discoveries raise the prospect that the dawn and dusk of life are intimately connected.”
            This discovery is significant because senescent cells could lead to a cure for cancer in the future.  Cells are more likely to divide uncontrollably and develop into cancer as their DNA becomes more damaged.  However, senescent cells prevent themselves from becoming cancerous “by stopping their own growth and by inviting immune cells to kill them.”  At the same time, an accumulating supply of senescent cells can lead to chronic inflammation that can cause damage to surrounding tissue and harm our health.
            I thought that the article included all the important information about the subject matter, but the information was not presented in a clear and concise manner.  The points made in the article were disorganized and out of order, and I felt that the article skipped around, making it a bit confusing.  The article started out by talking about the discovery of the senescent cells, jumped to their significance, and then went back to explaining how the cells were discovered.  I think the article would have been much more effective if the author finished each point before moving onto the next thing.  Another thing that I did not like about the article is that it was supposed to be about the significance of the senescent cells found in embryos, but the article mainly focused on the general topic of senescent cells found elsewhere in the body.  However, I did learn a lot from reading this article, and the information in the article is relevant to what we are currently learning in class.


Zimmer, Carl. "Signs of Aging, Even in the Embryo." Nytimes.com. The New York Times, 21 Nov. 2013. Web. 22 Nov. 2013.


3 comments:

  1. I read Blake’s review on the discovery of senescent cells, and I thought it was very interesting. I think Blake did a good job explaining what a senescent cell is, and why it stops replicating after about 50 times. She made it clear and concise. She also did a good job bringing up the topic of cancer, and how cancerous cells do not have the same trigger that causes them to be destroyed, and they keep on multiplying. I thought that was a very good point, and the discoveries about senescent cells could possibly help lead to a way to stop cancer cells from multiplying. Another thing that Blake did a good job on was her point about how the article jumps around a lot. I found this confusing myself, and I think that she was right in saying that that is something the author could have improved upon.
    I think that Blake could have done a better job incorporating her quotes. The one about the dawn and dusk of life being intimately connected didn’t make sense to me and it would have been nice if she had explained it more, in addition to the fact that it was kind of a non sequitur. I also think that she could have talked more about how this relates to what we’re learning in class, because that could be a very interesting connection.
    In my opinion one of the most interesting things about this article and this review was the way that the senescent cells know when to stop replicating and how they invite immune cells to destroy them. I find it fascinating how the cells are aware when their DNA is too damaged to continue replication, and how they consciously take themselves out of the pool of replicating cells. Life really is the survival of the fittest, from complex multicellular organisms all the way down to the little cells that make up all life on Earth.

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  2. Blake's review of the article did a terrific job of summing up the main points without excess names or terms that would keep the reading from understanding the point of the article. She brought up and talked briefly of one reason why these senescent cells are so important: they are almost "autoprogrammed" in a way to prevent cancer which is a major field of research going on at the moment. Her use of the quote was interesting- It was a line that also stood out to me when I had read the article myself. It's certainly a a cliche thought, although I think in this context, it works perfectly as these kinds of ideas are often overlooked.
    I do think Blake could've used this article to make a stronger connection than " we are learning this in class". I know this article stood out in particular to me because I remembered watching a documentary on aging that spoke about telomeres and telomerase, and perhaps instead of connecting it closer to home, such as what were learning about in class, made a connection to what I just mentioned, or even possible ways to incorporate this newfound knowledge into cancer research.
    I have always found this idea of aging an incredibly interesting topic. I remember when I was younger, I was vehemently against the idea that aging could be stopped, but one night, I watched a documentary on the exact topic, and the biology around it. The idea that cell aging can start even as an embryo, when the fetus is developing it a strong notion, since embryo's give us this idea of "new life". It also connects back to what I learned about telomerase and telomeres, since telomerase repair the ends of the DNA, and so the cell wouldn't have to die off, but could replicate forever. I thought this was a great idea, but then after more research, revealed that the increase of telomerase increased the risk of cancer.

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  3. After reading Blake’s review of the article, “Signs of Aging, Even in the Embryo” I thought that she did a great job reviewing it. I thought that she did a great job summarizing the article. I also thought it was interesting how she described what scientists previously thought about the cells and how the doctors discovered new things through their studies of fetal human cells. I also thought it was interesting how she integrated the information about the discovery of senescent cells. I also thought she did a very good job of discussing how this discovery was significant in society. For example, she says, “Cells are more likely to divide uncontrollably and develop into cancer as their DNA becomes more damaged.” She also did a great job summarizing the article, rather than writing what the author put.
    Though she did a great job reviewing the article, there are a few changes that she could make. For example, she could give a little more background information about the cells and the experiments that they used to find them to make it easier for the reader to understand. Also, I thought that Blake could have integrated quotes better from the article. For example, the quote that she included for “the discoveries raise the prospect that the dawn and dusk of life are intimately connected” didn't improve her review and it actually made it more confusing.
    One thing I learned from the article was the reason why the cells eventually stop dividing is that the DNA gradually accumulates damage, and switches on a set of genes that cease all growth once the DNA becomes too damaged. I thought that this was very interesting. Overall, I thought that Blake’s review was very interesting and it I learned a lot about aging in cells.

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