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Deep Brain Stimulation

Submitted by johanthomas on Thu, 04/27/2017 - 00:11

Deep brain stimulation (DBS) is a therapy used to treat a variety of diseases including Parkinson's, OCD, depression, and even chronic pain. It's a surgical procedure implanting electrodes into the brain in optimized areas to reduce symptoms of disease. As with any brain surgery, there is a very serious risk of complications occuring after the procedure.

DBS works by blocking electrical signals in the overactive areas of the brain where the electrodes are placed. The system is called a neurostimulator: a battery operated device that can deliver the electrical stimulation. The battery is also implanted subcutaneously usually under the collar bone or in the abdomen.

Mammal Birth

Submitted by johanthomas on Thu, 04/20/2017 - 01:36

Mammals share some distinct characteristics. All mammals are vertebrates, warm blooded, they have body hair or fur, breathe using lungs, and nourish their young with milk. Mammals give birth in three ways: placental, marsupial, and monotreme.

The placenta is an organ that provides oxygen and nutrients from the mother, and removes excrement. The placenta enables placental mammals to survive far longer inside the uterus than other mammals. Blue whales can spend an entire year inside the uterus. When giving birth the umbilical cord tears and the newborn's own respiratory, circulatory, and waste disposal systems activates. Once outside the womb, the infant drinks milk from the mother's nipples. Placental mammals include humans, dogs, giraffes, and many more.

Marsupials are born very small. Kangaroo babies are only the size of a jellybean. The quoll are a marsupial that is born only weighing 18mg. They are born not fully developed, so they continue growing inside a pouch on the mother where they can drink milk from nipples. Some marsupials can 'pause' ther pregnancies in unfavorable conditions. Kangaroos can ever produce different types of milk at the same time for infants of different ages.

There are only five species of monotremes left on Earth. This includes four species of echidnas and the platypus. Monotremes use one orifice to reproduce, lay eggs, and dispose of waste. The eggs are soft shelled, and when the baby is born it suckles from milk secreted from pores on the mothers body.

https://www.britannica.com/science/placenta-human-and-animal

https://www.youtube.com/watch?v=sz3Yv3On4lE

Jellyfish

Submitted by johanthomas on Thu, 04/13/2017 - 00:06

Jellyfish are gelatinous zooplankton. Zooplankton are animals which allow the current to let them drift in the ocean. There are more than a thousand species of jellyfish found in every ocean as well as in both fresh and salt water. Jellyfish have been around for 500-700 million years. While many marine animals have been suffering due to ocean acidification, jellyfish continue to proliferate and increase their numbers as time goes on. Groups of jellyfish are called blooms or swarms. The bell of the jellyfish is called the mesoglea. The mesoglea is more than 95% water held together by proteins. Jellyfish can propel themselves if they need to by relaxing and contracting their bells -- they are the most energy efficient swimmers in the ocean. Jellyfish do not have a conventional nervous system made up of a brain or spinal cord, but a network of nerves in their epidermis forming a net. Jellyfish can detect stimuli from its environment using this nerve net. Jellyfish are carnivorous and use a small hole in the middle of its bell to consume plankton, crustaceans, fish eggs, small fish and even other jellyfish. Jellyfish release excrement from the same opening. Some jellyfish have light sensitive organs called ocelli which allow them to see. Some scientists believe they can even see in color. The box jellyfish has 24 ocelli, four of which are curved upwards to see through the surface of the water to find mangrove trees where it feeds. The box jellyfish is unique because it is one of the only creatures on Earth with a 360 degree visual field. Jellyfish have cells called nematocysts lining their epidermis. When triggered by contact, pressure in the nematocysts builds up to 2000 pounds per square inch and bursts, releasing barbs that pierce the skin and releases toxins. The effect can range from no reaction or just a tingle to severe skin damage. The sting of a box jellyfish can kill a human in under 5 minutes.

Scientists studying the hydromedusa (Aequorea victoria) discovered that it produces green flourescent protein when it gets agitated making it glow. After isolating the gene for the green flourescent protein (GFP), scientists can insert it into cells to tag proteins. This discovery earned the 2008 Nobel Prize in Chemistry because flourescence microscopy is really useful to study the functions of genes and modifications. This process has been used to observe cancer cells proliferate, study the development of alzheimers, and track biological functions.

Aplysia and Neuroscience

Submitted by johanthomas on Wed, 04/12/2017 - 00:14

Aplysia are large sea slugs found mostly in the Indo-Pacific ocean. These slugs release a cloud of ink when threatened and retracts siphons on its body when it is touched or in pain. Neuroscientists study Aplysia because they have some of the biggest neurons in the world and are easy to study. They only have about 20,000 neurons.  Aplysia are also a great model to study memory and operant conditioning.

David Glanzmen, a neurobiologist from UCLA uses Aplysia as a model organism to study the difference between short-term and long-term memory. His team takes advantage of the gill and siphon withdrawl reflex of the slug: scientists administer a small shock which causes the Aplysia to retract its siphon into its shell. If it is not a learned behavior, the slug only keeps the siphon withdrawn for a short time (about 10 seconds). If the behavior is learned, the slug keeps its siphon withdrawn for much longer (almost a full minute). Under a microscope, Glanzmen and his team form a neural circuit from just two cells: a sensory neuron and a motor neuron. The cells then grow together in culture. When the snail gets shocked, two observable changes happen to the neurons. For short-term memory, signals between the sensory and motor neurons get stronger (more neurotransmitter receptors) -- this is only temporary. For long-term memory,  the neuron actually grows new axonal and dendritic branches to pass even more signals. As the brain grows more and more connections, the snail learns to avoid the shocks by retracting their siphons.

Signs vs. Symptoms of Cancer

Submitted by johanthomas on Tue, 04/11/2017 - 00:43

A sign is an observable change that can be seen by someone else. A sign of disease could be anything from a fever to abnormal sounds from the lungs. A symptom is felt by the patient, but does not have to be obvious or discernible. Symptoms may be weakness of limbs, headaches, shortness of breath, ect.. Even while knowing all of the signs and symptoms in a patient may not yield an accurate diagnosis because signs and symptoms may vary in any individual. Everyone has a unique set of genetics and immune system which reacts differently to disease.

Cancer can cause almost any sign or symptom being an enourmously diverse disease, but it often shows none at all. The most dangerous cancers go unoticed until they are large enough to press on surrounding nerves, already at an advanced stage. Some general signs and symptoms of cancer may be weight loss, fatigue, pain, or skin abnormalities.

Woolly Mammoth Extinction

Submitted by johanthomas on Fri, 03/03/2017 - 13:07

Researchers compared ancient wooly mammoth DNA from 45,000 years ago to woolly mammoth DNA from just 4,000 years ago to try to see why they died out. 45,000 years ago mammoth populations were much larger than 4,000 years ago. The more recent animals had "this huge excess of what looked like bad mutationes in the genome" - Dr Rebekah Rogers of the University of California, Berkley. Towards the begining of their extinction, scientists theorize the mammoths had lost their sense of smell, remained isolated, and had a shiny coat. This could have occured because mammoths had many small group populations which limited genetic diversity. Researchers at Berkley want to use this knowledge to prevent extinction of mammals like the panda, mountain gorrilla, and indian elephant. If these animals reduce in population too much, they will still have low genetic diveristy if they can build their numbers back up.

Regenerating pancreas

Submitted by johanthomas on Fri, 02/24/2017 - 13:22

Dr. Valter Longo published in Cell journal a potential new therapy to treat diabetes. He cycled a special diet in mice to regenerate beta cells in the pancreas which release insulin in the presence of sugar in the blood. The diet involved starving the mice and then feeding them again in cycles. The equivalent diet in humans would be low protein, low carbohydrate, and high unsaturated fats (very low calorie) for 5 days, and then eating whatever they want for 25 days. Experiments in mice showed improvement in both type 1 and type 2 diabetes. Type 1 diabetes is caused by the immune system destroying beta cells in the pancreas. Type 2 diabetes is caused by an accumulated resistance to insulin by overexposure (unhealthy lifestyle). Dr. Longo stated: "Scientifically, the findings are perhaps even more important because we've shown that you can use diet to reprogram cells without having to make any genetic alterations." When trying the diet with humans results included weight loss, lower blood pressure, lower levels of the cancer causing hormone IGF-1, and improved blood sugar levels.

Dr. Longo does not advise anyone to try this diet without the approval of a medical expert because it is more complex than people realize.

http://www.bbc.com/news/health-39070183

Manuscript Submission Guidelines

Submitted by johanthomas on Fri, 02/24/2017 - 12:55

The American Journal of Tropical Medicine and Hygiene has its submission guidelines posted at the website: http://www.ajtmh.org/site/misc/ifora.xhtml

To submit a manuscript the following components are necessary:

A cover letter, the title of the manuscript, a description of the significance of the manuscript, a confirmation that the manuscript is original work, disclosure of all conflicts of interest, names and signiatures of all authors, and the completion of a copyright form.

There are also specific formatting styles the journal requires to keep the material consistent and understandable.

Induced pluripotent stem cells

Submitted by johanthomas on Wed, 02/15/2017 - 23:37

Stem cells can differentiate into any cell in a multicellular organism. Stem cell research has potential to pioneer an entirely unique way to study and treat disease. Stem cells are most commonly found in embryos. There is a lot of contraversy in the ethics of harvesting human embryonic stem cells because it destroys the embryo. In 2007, researchers developed a method to undifferentiate skin cells into stem cells. Almost all cells in an organism has the same DNA. Differentiated cells only translate and "switch on" certain genes to function in a particular way -- cell programming. This method involves finding the genetic switches to program stem cells and artifically switch them on to reset the cell function. The research team found these switches by reducing the 20,000 possible gene candidates to about 100 using gene databases. The team used knockout mice to evaluate each gene candidate's ability to make pluripotent stem cells. After 3 years and hundreds of thousands of cell cultures, the team narrowed the candidates to 4 genes. A virus was used to insert the 4 genes into mice skin cells and within 4 weeks the skin cells completely converted into stem cells. These induced pluripotent stem cells were indistingiushable from embryonic stem cells. Now, we have the method and ability to convert human skin cells into pluripotent stem cells.

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