ziweiwang's blog

In CMT, there is demyelination of distal nerve, resulting in a loss of sensation and ability to control distal limbs. CMT is also marked by deformities in the hand and feet due to a lack of muscles in that region.  The specific mechanism of this disease is that there is demyelination of the nervous system, and since myelin sheath is crucial in maintaining signaling speed, the distal nerves are most affected by this disorder. Because of the demyelination, a person who have this illness is unable to control their feet very well and may result in stumbling, and loss of muscle in the feet, which may cause deformities because the muscles are unable to support the foot correctly. The disease also cause the loss of sensation in hands and feet, which may result in the inability to tell if they are hurt.  The disease onset of this disease is during the 20s to 30s, however, there have been cases where the onset has been earlier. There is a wide range of symptoms with people who have this disease, with some needing braces and other orthopedic devices to maintain mobility. However, CMT1A is not fatal.

One of the major catergory of difference that makes the photos look different or simmilar is what is in the picture. In the example given for example, the things that the most different is the weather one of the picture is clearly taken at a sunny day and the other is taken at a cloudy windy day. Another thing that is noticable is that one of the picture has people in it and the other does not. Another thing that is diffferent and would cuase the photos to be quite different is perspective. The place where the picture was taken is slightly different and the angle that it is taken from, again is slightly different. Becaus of thsese slight differences, it can be seen that one of the picture includes the library, others don't. In one picture the tree is closer compared to the other photograph.Another catergory of difference is how  the picture is organized. One of the figure has large borders, and the other does not. One has  large clear lettering and the other does not. One have black arrows and the other have blue arrow that is relatively hard to see against the blue background. The last catergory of difference is much less noticable, is the quality of the picture. some of the puicutres are more grainier than the other.

The inference for the first type is that the picture was taken by different people at different time, the secound type is due to the fact that the agle that the camera is being held is different. the third catergory is due to difference in how the picture are formatted and the forth type is due to the fact that they used a differnet camera.

One of the major catergory of difference that makes the photos look different or simmilar is what is in the picture. In the example given for example, the things that the most different is the weather one of the picture is clearly taken at a sunny day and the other is taken at a cloudy windy day. Another thing that is noticable is that one of the picture has people in it and the other does not. Another thing that is diffferent and would cuase the photos to be quite different is perspective. The place where the picture was taken is slightly different and the angle that it is taken from, again is slightly different. Becaus of thsese slight differences, it can be seen that one of the picture includes the library, others don't. In one picture the tree is closer compared to the other photograph.Another catergory of difference is how  the picture is organized. One of the figure has large borders, and the other does not. One has  large clear lettering and the other does not. One have black arrows and the other have blue arrow that is relatively hard to see against the blue background. The last catergory of difference is much less noticable, is the quality of the picture. some of the puicutres are more grainier than the other.

The inference for the first type is that the picture was taken by different people at different time, the secound type is due to the fact that the agle that the camera is being held is different. the third catergory is due to difference in how the picture are formatted and the forth type is due to the fact that they used a differnet camera.

According to the review article,fish that have had the DIO3 gene knocked out (a gene that binds to T4 and prevents it from affecting certain cells) have a higher neural crest cell proliferation migration and activation as well as apoptosis. In adult mice, hypothyroidism decreases mitotic neuroblast but not proliferation progenitosin SGZ, decreased number of committed neural progenitors and mature neuroblast and have reduced level of immature hippocampus neurons. Other studies have shown that OPC derived from SVZ-NCS requires a TH free environment, and a decrease in TH leads to a decrease in neurogenesis but not in oligodendrogenesis. The figure in the review article indicates that an increase in TH would cause the NSC commitment, and the lack of TH would cause determination in glial cells.  In studies that were conducted with TTR null mice, which have a lower thyroid hormone level, had reduced the apoptosis of progenitors in SGZ in adults. Other studies using TRa1 and DIO3 also confirm that in general, an increase in thyroid hormone leads to an increase in neurogenesis and neuron cell differentiation. A decrease in thyroid hormone generally indicates that there is a higher amount of oligodendrogenesis, as well as better remyelination of neurons. However, all of these studies are done in adult rodent brains and not developing zebrafish brains. 

According to the review article, fish that have a DIO3 gene(a gene that binds to T4 and prevent it from affecting certain cells)knocked out have a higher neural crest cell proliferation migration and activation as well as apoptosis. In adult mice, hypothyroidism decreases mitotic neuroblast but not proliferation progenitosin SGZ, decreased number of committed neural progenitors and mature neuroblast and have reduced level of immature hippocampus neurons. Other studies have shown that OPC derived from SVZ-NCS requires a TH free environment, and a decrease in TH leads to a decrease in neurogenesis but not in oligodendrogenesis. The figure in the review article indicates that an increase in TH would cause the NSC commitment, and the lack of TH would cause determination in glial cells.  In studies that were conducted with TTR null mice, which have a lower thyroid hormone level, had reduced the apoptosis of progenitors in SGZ in adults. Other studies using TRa1 and DIO3 also confirm that in general, an increase in thyroid hormone leads to an increase in neurogenesis and neuron cell differentiation. A decreaseinf thyroid hormone generally indicates that there is a higher amount of oligodendrogenesis, as well as better remyelination of neurons. However, all of these studies are done in adult rodent brains and not developing zebrafish brains.

According to the review paper, the timing of thyroid development is happening during 2nd day, and thyroid hormone production starts after the third day. This means that the experiment is done after the fish has been producing a normal amount of thyroid for about two days.  

Neurogenesis: neurogenesis seems to occur from day 1 to day 3 after fertilization. The experiment is done after neurogenesis has been happening for a few days. In zebrafish, it is also notable that adult zebrafish have more active neurogenesis compared to mammalian species.

Oligodendrogenesis: oligodendrogenesis seems to occur from day 2 to day 7 after fertilization, meaning that the Thyroid hormone is added while it was occurring. 

figure1. Image of an European Robin (Erithacus rubecula) Also known as robin redbreast, taken in Wakefield, England. These birds are common year-round in Europe and were first described, Carl Linnaeus. "robin" flickr (photo by philip oleary)  https://www.flickr.com/photos/philip_oleary_photos/8592206800 shared under Creative Commons (BY-NC-ND) licence

I actually almost laughed out loud, during class when I saw the article title How I learned to love flow cytometry. Because it was so accurate of an title. Over the summer, I actually got some experience working with the machine, and it takes quite a long time to get used to, and it was one of the things that I never quite got used to. I got used to handling mice before even being able to explain how flow cytometry work properly. Being fair, it hurt a lot less to handle flow cytometry. The machine had a lot of problems, but biting the people handling them was not one of them. to be honest, I still can't explain it very well, and if I don't write it down somewhere I will probably not be able to remember any of it. 

Basically, flow cytometry is when cells are labeled with specific antibodies and tags then the cells are passed through the machine to detect certain proteins such as antigens and other proteins. when the cell is passed through the tube the computer shines the laser at it and record the size of the cell, the weight of the cell, and what label it has. the scientist using the machine can change the graphs so that they can make a bunch of graphs that suit their needs. one thing that can be done is to show whether the cells have clumped or not. another is how much of one cell is expressing a certain protein. By manipulating the graph, the researcher can see that in certain cell population such as t regulatory cells, certain protein is missing in mice that are missing certain mutations. Because there are not as many cells that are needed for this, the technique is popular both in the lab and in a clinical setting. 

To take this picture, I walked to the closest vendor that was selling Spinacia oleracea leaf.  the leaf that I got specifically was baby spinach, not of the larger variety. I specifically chose a leaf that was not previously damaged and had a relative rounder leaf, and it was still fresh enough that it did not wilt when held up, even at the edges.  I then took a picture of the leaf, holding it by the stem, against a gray background and took a picture.  I held the stem so that most of the stem was covered up by my hand and the only the leaf was visible. When I was taking the picture, I held it up close enough that the leaf was relatively center and filled almost the entire picture rather than just around the corners. the picture that I took was slightly blurry, and as a result, the full-color difference between the differing part of the leaf was only slightly visible.  Then I took a bite that was large enough to cover half of the leaf, held it up again much in a similar position but with further distance so that the hand and the leaf fit within the bottom half of the picture, which was in portrait mode.  and took another picture with a similar background.  

While it does not matter where the plant leaf was obtained personally I obtained the leaf at one of the dining halls at University of Massachusetts Amherst. Specifically, the one that I have pointed out in the map. The gray background was the high chairs that they had at the dining halls.  However, as long as the leaf is baby spinach and the background is a similar color, there should not be any reason why the picture would be different. 

In the study with the LDL, 25 patients with high blood LDL, was gathered. The 20 of patients had high blood cholesterol, but none of the patients were likely to have FH.  Five patients with heterozygous FH has gathered apart from the 20 patients. The participants with heterozygous were determined by their high LDL blood level in the blood which was much higher than the patients. The 20 participants were given two types of labeled LDL. The first type of LDL that was used is the patient's own LDL, which was extracted by their blood, labeled and inserted back into the body. The other type of LDL was obtained from first-year medical students who had normal blood cholesterol levels and fit the criteria for giving blood. The patients were then all admitted to the hospital for the study and were given a relatively high-fat diet.  The LDL turn over was studie by taking blood from taken from the donors and removed and the amount of the two labeled LDL was detected. 

The result of the study is that while in patients with Het FH, neither LDL was absorbed well. In some of the 20 patients who did not have FH, the patients had a much higher turnover rate of medical student's LDL compared to their own LDL. This indicates that the patient's own LDL is not structurally compatible with the LDL receptors in the cell, and indicate that the patients were unable to make normal LDL. since the absorption of the LDL in the blood causes the cells to decrease the production of LDL, it is not unreasonable to say that the unusual structure of the LDL protein is the cause of high cholesterol in these patients. If that was a true one of the ways that it can be treated is to inject LDL from someone else in to their blood. However, this treatment is not cost-effective, since the patients who have a misformed LDL inly have a slightly higher pressure than normal.