Drafts

The 2018 Nobel Prize in Physiology and Medicine was awarded to James P. Allison for his work in tumor immunology.  In 1977, Allison found evidence that leukocytes, also known as white blood cells, the key player of the innate immune response, were prevented from interacting with cancer cells due to the cancer cells having additional proteins.  His work in later years investigated the factors that prevented the immune system from working against cancer cells. He was one of the first to isolate the T cell antigen receptor complex protein. He showed that cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a protein receptor in T cells that downregulates the immune response.  Cancer has the ability to induce upregulation of this protein, giving the tumor the ability to avoid inducing immune responses. Allison showed that antibody blockade of CTLA-4 can lead to enhanced tumor immune response. This concept lead to the creation of Ipilimumab, a monoclonal antibody that interacts with CTLA-4.

In Physics 132 Laboratories this week, students were challenged to calculate the volume of the W.E.B. Du Bois library on the UMass Amherst campus. The only tools given were a yardstick and a 12 inch ruler and students were not allowed to enter the library or hop the black fence surrounding the library. My group approached the assignment by first taking the height measurement of one brick that we were able to measure by the entrance. We then used the nine sections of the library’s height structure to estimate the number of bricks. Next, the number of bricks was counted by the naked eye for one section and multiplied by a factor of nine to obtain the total number of bricks that make up the height. In order to measure the width and length of the library, we looked at the equal square pattern of the cement on the ground around the library. We counted nine square patterns to line up with the front of the library and to its depth. The measurement of one square pattern was then taken and multiplied by a factor of nine. After having collected the data, students then returned to the labs and calculated the volume. Shortly after, results were discussed within the groups and the average volume was calculated.

The main focus of this article is to show an improvement in preventing the risk factors of diabetic foot after weeks of exercise therapy. The article focuses on multiple diabetic complications and the role of exercise therapy in terms of improving conditions.  Exercise therapy is known to improve blood glucose and insulin sensitivity as well as weight loss. These are theorized to be factors in reducing the chances of developing neuropathy. The subclinical onset of neuropathy is usually more peripheral rather than central. Sensory nerves are detected before motor and autonomic nerves. Detecting minor nerve damage before full onset neuropathy can be difficult due to the fact that nerve conduction velocities do not significantly change early on all the time.

Tetrahymena is a genus of free-living ciliates, a freshwater organism that can inhabit lakes, streams, and ponds and can be found almost everywhere and in a variety of climates and their main food source is bacteria. Tetrahymena were selected in this experiment to study food vacuole appearance. This was done by taking 5 samples of cells: one immediately when the India ink was added, 10, 20, 30, and one at 40 minutes. Samples were taken in small test tubes, and inside a mixture of 100 µL sample of the Tetrahymena and India Ink and 20 µL of dilute glutaraldehyde to fix the cells was added at each interval of time. After all of the samples were taken, they were studied under a microscope at the 10X objective, then the number of marked vacuoles formed for ten different cells were recorded for each of the time intervals, then graphed. Tetrahymena feed by the process of phagocytosis, where is the engulfing of other cells or particles. Phagocytosis can be quantitated by counting the number of vacuoles that form in a defined time period.

Today we quantified DNA that was extracted in an earlier lab session. A single sample of DNA was split into two, one being treated with RNase while the other was not. Each was measured using a spetrophotometer, which tests the absorbance of just one microliter of the sample, just enough to form a drop. The greater the absorbance, the more DNA in the sample. The sample treated with RNase is expected to have a lower absorbance because the RNA is degraded. It turns out that a lot of the "stuff" extracted was also RNA along with the DNA. Our absorbance for the RNase-treated sample was a bit lower than expected, meaning our DNA sample was not very pure. We then did gel electrophoresis with our samples. With each sample, both the RNase-treated and non-RNase-treated samples, we diluted some to 50%, which resulted in a total of four samples. Each of these four samples were treated with loading dye to allow it to sink when loaded into the gel and indicate the migration of the samples across the gel. We poured the gel with a dye added to it that will allow the samples to be visible under blue light. After the gel had solidified, we loaded a standardized DNA ladder into the first two wells. We then loaded five microliters of each sample into the next four wells. We ran the gel at 100 volts for 30 minutes, and we viewed the gel under blue light to illuminate the migrated samples. As expected, the samples treated with RNase only had one stripe, which the samples that weren't treated with RNase had two, one that represented the DNA and one that represented the RNA. The DNA was longer in length, so it did not migrate as far as the RNA, which formed a stripe much farther down the gel. Also as expected, the diluted samples had fainter stripes, showing that there was less DNA and RNA contained. 

Types of Diabetic Neuropathy

Diabetes can lead to many complications over time. One of the most common and relevant complications is neuropathy. Diabetic neuropathy, or nerve damage, is most commonly caused by elevated blood glucose levels (hyperglycemia) over long periods of time. There are four major types of diabetic neuropathy: peripheral, proximal, autonomic, and focal neuropathy. Peripheral neuropathy is the most common type of neuropathy in people with diabetes and can be either acute or chronic. Peripheral neuropathy affects the nerves that lead to the body’s extremities such as the feet, hands, arms, and legs. Proximal neuropathy, also known as amyotrophy, is a neuropathy found more often in type 2 diabetics. It can be caused by endoneural micro vessel disease and causes muscle weakness in the upper legs, buttocks, and hips. Autonomic neuropathy often co-exists with other complications such as peripheral neuropathy, but it can be isolated as well. Autonomic neuropathy is nerve damage to the central nervous system which can lead to complications such as: tachycardia (rapid heartbeat), orthostatic hypotension (low blood pressure), erectile dysfunction, sudomotor dysfunction, and impaired muscle control. Autonomic neuropathy can also affect many organ systems and lead to a serious complication known as cardiovascular autonomic neuropathy (CAN). CAN results from damage to nerves that innervate the heart and blood vessels. Lastly, focal neuropathy is specific to one single nerve and causes pain in that lone location. It is found commonly in older individuals and is also known to improve itself over time.

Jaguar population continues to decline and suffer as a direct result of human impact. As seen in several instances, the removal of just one species can cause the entire ecosystem to change rapidly or deplete within years. Jaguars are the top predators in their environment, so they play an important role in controlling the populations of other species. This helps keep a balance in the food chain, and a healthy environment. Since their forest homes have continued to be destroyed, jaguar populations now occupy only a small fraction of their original territory, and are so exclusive that we cannot even determine how many are left in the wild. As the cause for this issue, it is our job that we protect and conserve designated habitat patches and corridors so that jaguars may be allowed space and ability to survive and grow. Providing protection for the connectivity between different landscapes will allow the jaguars to be able to expand their population gene pool, which will then in turn create a healthier, more stable population. The corridors would also allow for jaguars to move unnoticed amongst human development while maintaining the ability to migrate and create their own territory.

23andMe is a genetic testing company that collects DNA samples from consumers and in return sends them ancestral information. The founding of the company would not have arisen if it were not for the Human Genome Project. The techniques used to sequence the human genome are utilized by 23andMe to obtain genetic data in a cost-effective and efficient manner. 23andMe collects spit samples from consumers and sequences the DNA using the same principles as Sanger Sequencing but in a more modern and digitized way. Similar to Sanger Sequencing, chunks of overlapping DNA are analyzed. The sequence is then compared to a reference data set of DNA to find ancestry information. While it may seem like cool to use genetic testing to learn your ancestry, 23andMe raises several ethical concerns. Giving the company your genetic data has been regarded as a violation of privacy because it’s possible for the data to be shared among other corporations such as pharmaceuticals and biotech corporations. Shared genetic data can lead to discrimination from health insurance companies. While there may be laws in place to prevent this, these laws are always susceptible to change. Just like when information leaks on the internet, if genetic data were to be shared, the privacy cannot be taken back. In addition, while 23andMe might have regulations to protect the privacy of consumers to a limited extent, there is no way of knowing what will happen to the genetic data in the future when the owners of the company are not around anymore. 

Cardiovascular disease is caused by a combination of all three factors, but lipid control is thought to be the most influential. Often, cardiovascular problems can arise from the development of atherosclerosis which is an increased risk in diabetics. Poor glucose control or resistance to insulin causes a lack of nitric oxide production which is important in maintaining vascular flow. The lack of sufficient nitric oxide leads to an increase in plaque formation within the blood vessels. Lastly, neuropathy is caused by a metabolic cascade resulting from a lack of glycemic control, a long duration of diabetes, and potentially vascular abnormalities as well. Hyperglycemia causes the polyol pathway to produce more sorbitol from glucose, but at the same time this process consumes NADPH which results in less cofactor available for glutathione reductase. This inhibits the cells’ ability to respond to oxidative stress. Oxidative stress is defined as an imbalance between antioxidants and free radicals in one’s body. Too many free radicals cause chemical chain reactions due to their high reactivity. Conversely, anti-oxidants have been proposed to prevent generation of free radicals (or reduce the impact of free radicals). Oxidative stress can alter nerve blood supply, nerve structure, and endoneural metabolism. High glucose levels also are found to be directly correlated with the production of advanced glycation end-products (AGE). AGE’s are produced by a chemical transformation of sugars binding amino acids or fats. High blood glucose levels and increased fat/lipid levels can lead to the production of AGE’s. When AGE interacts with receptors (RAGE) it can lead to oxidative stress. In rats RAGE is expressed in endothelial and Schwann cells. Incubation of these neuronal and Schwann cells with AGE’s leads to cell death. Vascular complications can also lead to neuropathy. A lack of glycemic control can cause microvascular blood vessels to narrow or harden due to plaque build-up known as atherosclerosis resulting in a restricted blood flow to the nerves. This lack of blood flow causes damage to the peripheral nervous system thus leading to complications such as neuropathy and foot ulcers.

In the research done by Laurent Debarbieux et al on treating P. aeruginosa lung infections through bacteriophages, the authors used mice as their test subjects, as well as different primary colonization and chronic strains of the bacteria P. aeruginosa, and the virus they called PAK-P1. Even though the research revealed bacteriophages' effectiveness in treatment in vitro, the researchers were questioning its effectiveness in vivo. Through this article, they revealed their research on the effectiveness of treatment of bacterial infections with the bacteriophages. Their hypothesis: if bacteriophages are effective in attacking only the bacteria, the bacteriophages will significantly reduce the bacteria in the victims and thus saving them. The dependent variable was thus the survival of the test subjects, the mice, and the independent variable is the amount of bacteriophages. The controls were infected mice not treated with any bacteriophages. Experimental evidence reveals that timing and dosage of bacteriophages mattered in saving the lives of the mice. This is therefore important in possible treatment with humans.