Defective Ca2+ channel clustering in axon terminals

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This article discuss a defectives in calcium channels clustering in axon terminals that disturbs excitability in motoneurons resulting in spinal muscular atrophy. The article defines Proximal spinal muscular atrophy (SMA) is a motoneuron disease for which there is currently no effective treatment. SMA is essential the death of motor neurons. This disease is more common in children. This disease is process and will result in immobilization of individual who have it. The article discuss two specific genes that are associated with this disease, they are SMN1 and SMN2.

The SMN1 gene is responsible to determine the length of a protein. The SMN2 gene code for a truncated protein lacking the functionally important domains at the C terminus that are encoded by exon 7(defined by the article). SMA is caused due to lack of SMN1, causing the lack of axon elongation. In the study they noticed that mice lose most of their motoneuron abilities during the critical development period. This means that when some is born they have full motoneuron capabilities. Within the time period after birth were these motoneuron issues begin was a major focus of this experiment. They article concluded that these motoneuron problems in SMA patients are a result of differentiation of motor endplates.

This article also focus its experiment on Cyclic adenosine monophosphate (cAMP). cAMP is defined as a cyclic nucleotide, adenosine 3′,5′-cyclic monophosphate, that serves as an intracellular, and sometimes extracellular, “second messenger” mediating the action of many peptide or amine hormones. Basically means that they help to get certain hormones inside the cell; hormones like epinephrine, which that otherwise could not do the intended response or reaction. Its main purpose is of cAMP is to activate of protein kinases. Protein kinase can then modify other proteins by adding phosphate group to them commonly known as phosphorylation. The article concluded that 8-CPT cAMP enhances spontaneous Ca2+ influx into spinal motoneuronsm. Which means that this specific 8-CPT cAMP might be a possible treatment for SMA patients.

Overall, I found this article to be extremely interesting and really content rich. I think this study might give individuals suffering from SMA some hope for future research that might lead to a possible treatment. Also I was surprised that calcium plays such a huge role in disease like SMA. I definitely recommend this article 

Seeing is believing! Imaging Ca2+-signalling events in living cells.

A.) activation of Ca2+-activated K+ channels by Ca2+ sparks results in spontaneous transient outward currents (STOCs), hyperpolarizing the plasma membrane (increased membrane potential; Vm). This reduces activation of voltage-operated Ca2+ channels (VOCCs), decreasing Ca2+ influx and global [Ca2+]. This can act as a negative feedback mechanism, whereby localized Ca2+ release from the sarcoplasmic reticulum (SR) lowers mean cytosolic [Ca2+], restricting further store loading.

B.) spark-dependent activation of Ca2+-activated Cl− channels causes spontaneous transient inward currents (STICs), with membrane depolarization and Ca2+ channel activation. This results in positive feedback, with Ca2+ release from the SR promoting further Ca2+ influx.

Above is an image directly from the article.

The article discusses a study that take a closer look at what is happening with calcium on a cellular level. Some of this study is conducted on jellyfish. They used jellyfish because they were able to stain its protein with a fluorescent dye. The purpose of staining the proteins is to use them as bio-markers for a better understand of where the calcium is going and why. In their research was done because they know that muscle contractions require the presence of calcium. With the knowledge that calcium is required they then realized that calcium play a vital role in excitation of contraction coupling.Excitation of contraction coupling is defined  to describe the physiological process of converting an electrical stimulus to a mechanical response.This coupling is vital to muscle physiology.This article also calcium sparks which is depicted and explained above. Basically these Calcium sparks  act as the building blocks for larger transients during the contraction of cardiac muscle (at least in this study). These calcium sparks result in both inhibitory and excitatory responses. They do this by increasing and decrease calcium sensitivity. The calcium sparks are also responsible for both positive and negative feedback. Overall, this article was pretty difficult to navigate through, but it is definitely full of great proven research. The article conclude that they would like to conduct another experiment were they could take a closer look at the use of genetically coded calcium indicators expressed in organelle and/or tissue in identify specific purposes.  

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Calcium equilibrium in muscle.

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This article discusses a study conducted on frogs that compare the effect of calcium on muscle. Within the experiment they focused on 6 muscles of the frogs the tibialis anticus longus, peroneus, ileofibularis, sartorius, and the semitendinosus.The experiment itself was pretty complicated, they had each muscle dissected and soaked in 100 ml of solution. The solution consisted of  CaCls, NaC1, and KC1.The muscles were soaked for 5 hours and then tested to see the influx of calcium within a given muscle.

The reason for this experiment was to determine the permeability (ability to let things in or out of the cell)
of the muscle cell membrane to calcium.Also the experiments goal to calculate the energy requirements
to maintain the calcium in a steady state. This is vital to muscle metabolism because active working muscle needs calcium. This test will hopefully give us a ball park figure of are calcium influx within a given muscle.

Within this experiment they focused a huge part of the study on the metabolism satorius muscle of frogs. The flux of calcium within the cell during steady state was 0.8 mM/(liter hr) This information help to conclude the idea that their is a calcium pump within the muscle. The calcium pump is responsible for pushing calcium out of cell. The calcium that is being pump out of the cell must be coming out with quite some force, because going against a an chemical gradient.The flux is low but the maximum energy required per hour to pump calcium out of the cell against this high gradient is key in muscle metabolism.

Overall, I think this article does a great job on highlighting the need for calcium in muscle metabolism. I think its interesting to learn that their is in fact a mechanism within a given muscle that is responsible for the maintenance of calcium levels. Also i think it would be interesting to fin out how this mechanism to maintain calcium levels works in human muscle. 

How a muscle contraction is signalled - Animation

This Video is amazing it really grasps the main reason as to why calcium is so essential in the contration of any muscle. I hope you enjoy the video and can see a visual image of what is actually happening during a muscle contration on a mirco level :)

I choose this picture because it shows the daily recommendation of calcium for all different phase throughout life. Check it out and see if you close to your daily recommendation.

Nutritional aspects of the prevention and treatment of osteoporosis

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Wow. This article is a great outlet that can be used to discover what osteoporosis is, how to prevent it, and if your genetically at risk for getting osteoporosis. Within this article it also defines osteoporosis as a skeletal disease that is associated with low bone mass and microarchitechural breakdown of bone tissue. Resulting in increase chance of bone fracture and overall decrease in bone strength. I appreciated this article because it showed the real issue of osteoporosis in our population. One statistic I found within the article that supports the concept concerning the number of individuals suffering from osteoporosis is stated below: “ After age 50, 1 in 2 women and 1 in 4 men will have a osteoporosis-related fracture”. The actual fracture that they are talking about in this article is caused from too much stress on aging weak bones. 

Genetics play a huge role in determining if an individual maybe at higher risk of developing osteoporosis later in life. The article stated that genetics play up to 80% of determining an individuals peak bone mass. However, we can predict the outcome of the other 20% by choosing a healthier lifestyle. A healthier lifestyle would include no smoking, a good diet, exercise daily, and limit alcohol consumption. Also everyone needs to make sure they are meeting the recommended calcium intakes either through food or through calcium supplements. Calcium supplements where also discussed in this article and it said, “ one positive aspect of calcium supplements is that it reduces bone remodeling.

The top 5 important reason why we need to meet the recommended calcium intakes I found in this article are stated below:

1.Calcium is required for normal growth and development of the skeleton.

2.Adequate intakes of calcium is needed to meet optimal peak bone mass.

3.Calcium intakes are closely related to affecting the rate of bone loss while an individual is aging.

4.Calcium is important in the bodies fluid due to its effects on binding proteins, metabolic functions, and operating as a signal transmitter

5.Lastly, calcium is essential in the contraction and re-contraction of muscles

I though this was important to highlight as it ultimately explains to my blog readers why once again calcium is essential to our bodies.

This Article also did a great job explaining other key components that are essential in the prevention of osteoporosis and the promotion of healthy bones. These key components are Vitamin D, protein, Magnesium, and phosphorus. Vitamin D is vital to bone development and maintenance of bone, because vitamin D can reduce risk of osteoporosis and bone fracture in older people. Protein was discussed in this article to play a major role in repairing muscle and bone. It is also essential component in bone tissue. More than 60% of the bodies’ magnesium is stored in the bones. Magnesium is important to the bones because it decreases the hydroapatite crystal size. The decrease in the crystal size will result in the prevention of brittle bones.

Overall, I really like this article it was informative and proved actual studies based on our population. If you take the time to read this article make sure to check out all the graphs, because I found them very helpful.

 

The Importance of Meeting Calcium Needs with Foods

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This article is great because it recognizes that there is a current calcium crisis in America. The article also provide the reader with the actual dietary recommendations of calcium intake for all ages as stated below:

•        1-3 year of age = 500 mg of calcium daily
•        4-8 year of age = 800 mg of calcium daily
•        9-18 year of age = 1,300 mg of calcium daily
•        19-50 year of age = 1,000 mg of calcium daily
•        50+ year of age = 1,200mg of calcium daily

Along with the crisis the article shares its concern with child developed due to the lack of meeting recommended calcium intakes.  Here is a quote from the article that concludes those thoughts, "”As stated by the National Institute of Child Health and Human Development(NICHD), children’s low calcium intake is … a growing problem and a serious threat to their later  healthy growth and development” .This quote was pulled directly from the article highlighting the nation concern of children’s low calcium intake.

One benefit to reading this article was that it covered the current factors that in fact influencing the low dietary calcium consumption. It dedicated a section of these factors to the recent research, which shows that people are substituting soft drinks for milk. This is represented in a graph in the article that you should definitely look at.  

Coinciding with the factors influencing dietary calcium consumption, another major factor was that eating outside the home. “In 1995, the calcium density of away from home food was 343 mg per 1,000 kilocalories, whereas home foods had a calcium density of 425 mg per 1,000 kilocalories.” This quote from the article highlights the difference in calcium intake when eating outside the home, and how when you do eat at home you will probably be consuming more calcium.

One section of this article I found interesting was that one major problem of limiting calcium intakes in children was a direct reflection of the parents. I am when you think about it the parents buy, choice, and cook the food that their children will at least while at home. If parents can be more proactive in their food purchases and their preparations of that food their children will defiantly benefit from it.  Also the article stated that there is an increase in soda consumptions when families eat together at the dinner table.

Calcium is not bad fat! I learned this through this article that most people think that by cutting down their consumption of dairy products will result in weight loss; however, this article discuses the complete opposite. One fun fact I learned from this article was that low-fat milk contains the same amount of calcium as whole milk. It also supports the consumptions of calcium-fortified foods, like soymilk. Also this article shares health benefits of consuming calcium rich foods. Some benefits they communicated were reducing risks of osteoporosis, hypertension, colon cancer, stroke, and also can help maintain weight control. Check this article out is really helpful!
 

 

Calcium 101 (Health Short)

                                                          
This video helps to give a quick review of what calcium is and why it is so important for both bone and muscle health. Check it out and see for yourself :)

Calcium good for bones and heart?

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This article discusses a study done by “The British Medical Journal” that dealt with effects of taking calcium supplements on the heart.  They found that the people taking the calcium supplements had a 30 percent increase in heart attack compared to those who did not take the supplement. These results were not dependent of the sex or age of the individuals. I thought this article was important because growing up I was taught that taking supplements of calcium can only help your body. However, this research states that the calcium supplements might help your bones but can also increase your risk of heart attack.

This article also mentions a study conducted in 2008 that took 1,471 postmenopausal women and had them take a total of 1,000 mg of calcium a day in multiple doses. This study contradicted most other studies that stated that the reason why calcium supplement were so beneficial for our heart was because it helped with lowering the bad cholesterol or LDL and raising good cholesterol or HDL. However, through the help of a CT scan researchers in this study can conclude that higher doses of calcium supplements implies more disease of the arteries. The problem with the calcium supplements is that they cause an acute increase in the blood calcium levels much more rapidly than from food. This rapid increase in blood calcium levels is believed to be the cause of the artery damages.

Therefore, this article really pushes eating calcium rich foods versus calcium supplements. In the article is said and I quote, “your food is your medicine”.  I choose this article because it supports the idea that we should retain most of our daily calcium needs from food, which I myself am a strong believer of. This article also provides a list of recommended foods that have contain higher levels of calcium. The list ranges from dark-green leafy vegetables to nuts and seeds. Also I appreciated this article because it advocated consuming less animal foods and less salty foods.

As a vegan, I loved this article because it shows that you don’t have to eat tons of meat or dairy products to meet our daily recommendation of calcium, and further be healthy. This is supported in the article when it stated a study conducted in 1990 by Yale that looked at fracture rates in 16 countries around the world. They found that people in countries with the lowest intake of meat, eggs, fish and dairy products also had the lowest fracture risk. The main message I want you take from this article is that vegetables are essential and so beneficial to our bodies. So I am asking you to please try to retain the recommended calcium intake of 1000mg a day naturally, with REAL FOOD!

Maintaing Healthy bones

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In this article it laid out the purpose of calcium in the body and the ways in which one could go about getting the recommend amount of daily calcium. I will give a brief highlight on the Key concepts in this article.

The bone is always changing with the helps of the osteocytes or bone cells that are embedded within the connective tissue of a bone. Osteoclast and Osteoblast play a major role in the constant changes that the bone will experience. An osteoclasts function is to breakdown Osteocytes (bone cells). While the osteoblasts function is to make or form new bone. One important factor that is key in the promotion of healthy bone is that the bone maintains a relatively stable activity levels between the Osteoclasts and the Osteoblasts. For example if the Osteoclast is more metabolic active than the Osteoblast that could result in a much weaker bone that is more susceptible to injury from external or internal stress.

The article also focused on the peak bone mass (PBM). It stated that the average PBM is reached at ages 30 to 35. The article recommended that early in life one needs to focus on their bone strength and after reaching PBM they need to focus on maintaining that bone strength. However, throughout ones life you must always focus on maintaining a healthy and nutritious diet. Also the article stated that 20% of our PBM can be influence by our diet and lifestyle choices.

Overall I really enjoyed this article because it gave a list of non-dairy food that contained adequate levels of calcium. Some non-dairy foods that contai9ned calcium were, dried apricots, kale, and soya beans.