Saturday, August 4, 2012

Damage to Blood Capillaries in Diabetes

Capillary Problems and Blood Glucose

When a capillary narrows the flow decreases dramatically. If you halve the radius of a blood capillary the blood flow through the capillary decreases to one-sixteenth of its normal rate. 

This will cause an increase in blood pressure (think hypertension) which can lead to ruptured blood vessels. In the brain region, a stroke is possible. Heart attacks can occur with lessened blood flow to the arteries that supply the heart muscle.

Blood vessels capillary networks in diabetics are unable to relax well. Researchers believe  altered proteins involved in relaxation are affected by a glucose-derived molecule. The net result is possible hypertension, chance of strokes and increased obesity.

When insulin is not present in the circulatory system the level of glucose remains high in our circulatory system. It begins to decrease the level of nitric oxide, a chemical that increases the diameter of blood vessels. The continual exposure to high blood glucose levels leads to the eventual narrowing of the blood vessel system.

I  have not read this book. If you do read the book tell others the pros and cons.

Unfortunately, in diabetes, when a person has their diabetes under control, a small percentage of the glucose is converted to a sugar type that can modify the proteins.

In your blood vessels this modified glucose competes with a mechanism called phosphorylation that modifies an enzyme that makes possible the formation of  nitric oxide. Its name tells you what it does. Its called a nitric oxide synthase. It catalyzes the formation of nitric oxide, a blood vessel dialator. The modified-glucose wins out in the competition with phosphorylation and negates the formation of nitric oxide. Net result is constricted blood vessels that increase a diabetics chance for developing high blood pressure, strokes and heart attacks.

Researchers are focusing on blocking the mechanism that prevents the formation of the modified-glucose molecule. If that is successful the effect on nitric oxide production will cease and become normal and the danger from hypertension, stroke and heart attacks will diminish.

Interesting point to remember about nitric oxide is the nitro glycerine tablet a person takes to dilate their heart blood vessels in a heart attack. 

Wednesday, August 1, 2012

Glucose - Enzymes - Food for Thought

Glucose and Enzymes

All chemical reactions require enzymes to catalyze the reactions. How are enzymes produced?

In cells the nucleus, an organelle, contains DNA that contains our genome. The genome contains all the information that constitutes you. It is unique.

All of us basically share a likeness (physical, chemical, psychological, etc.)  to all that we are. Very small differences make us unique.

When a cell receives a message, from somewhere in our body ,that glucose is on its way to supply a basic ingredient for energy production our cells prepare to receive the glucose.

It seems simple. Glucose appears outside the cell, enters the cell, and produces energy that is immediately used or is stored for future use. There are two ways glucose can enter the cell. Both work when a person doesn't have diabetes.

Type I Diabetes occurs early in life and the cause is lack of insulin.

Type II Diabetes occurs later in life and insulin production is available. The factor that transports insulin into the cell is missing. 

The cell needs a factor present for glucose to enter the cell. In the nucleus of a cell there are two important molecules. DNA and RNA. Like a blueprint, the DNA has a code for the manufacture of the enzyme. It replicates the code for RNA. RNA receives the information and forms a complementary code. It begins the manufacture of a faulty trigger that doesn't insulin to enter the cell interior.

All this takes place in the nucleus and inner cell machinery. Here is where trouble can begin for a Type II diabetic. What if the DNA message has changed? What caused the message to change? How does the body compensate for the inability of insulin to function? Lots of questions.

If the cell manufactures a faulty factor, from information received from the nucleus, it won't catalyze the reaction that makes it possible for glucose to enter the cell. The result is the loss or ability to activate the factor that facilitates the cell membrane to ferry the glucose into the cell interior.

It doesn't matter if the levels of insulin are normal. Glucose that doesn't enter a cell means the glucose in the blood begins to rise. There is a solution from the kidneys. The second way glucose can enter a cell, and out of the bloodstream, is based on the sodium/potassium pump. The Sodium+/Potassium+ active transport Pump allows glucose, that is reabsorbed from the kidneys, to piggy-back with the Sodium with its transporter. The Sodium Transporter helps glucose enter the cell. Even though normal amounts of insulin are available but can't function to lower blood glucose the secondary active transport system is available.

To make the removal of glucose easier diet plays a role in the Type II diabetic. That helps control blood glucose and allows normal levels of glucose in the bloodstream.

With you always in understanding the confusing relationship of glucose, insulin and secondary active transport systems in the kidneys. 

Tuesday, July 31, 2012

Enzymes - Necessity?


They increase the rate of chemical reactions in living systems. Molecules at the beginning of a chemical reaction, called substrates, converted into different molecules called products.

All living cells need specific enzymes to occur at rates sufficient for life and at low temperatures (body heat) than inorganic catalyst temperatures(very high temperatures).

Enzymes determine the metabolic pathways that take place in a living cell.

Enzymes are not consumed by the reaction. They are used to catalyze the same reaction over and over until they are replaced from wearing out. The enzymes are highly specific for their substrate they catalyze.

Enzymes are affected by other molecules. Inhibitors are molecules that decrease enzyme activity. Activators increase their activity. They are, of course, part of negative feedback systems we discussed earlier, and help maintain homeostasis. 

Remember the perfect environment for living cells? Drugs and poisons are enzyme inhibitors. Temperature, pressure, chemical environments, like pH and concentration of substrate molecules, affect enzymes.

Continue to focus on how slight changes in any of the above factors can results in a change in the enzyme. Once changed the enzyme no longer catalyzes their specific chemical reaction.

Life is very fragile.

This is a "reminder" post about the significance of enzymes and how they play a very crucial role in human homeostasis.

Sunday, July 29, 2012

Food Pecking Order and Storage - Danger?

Carbohydrates, Fat and Proteins - Pecking Order

In Diabetes the emphasis is the breakdown product of polysaccharides to disaccharides to glucose, a monosaccharide.

What if, for a variety of reasons, glucose stays lower than normal. If you went to a diabetic camp, where your time exercising is high, you know what happens.

First line of supply is the storage of Glycogen in the liver. It is broken down to release glucose until the hypoglycemia returns to normal values of glucose.

If you are unable to ingest carbohydrates your body begins to call upon other sources to use as fuel.

The second line of defense is your fat storage centers. In the production of energy fat enters the energy cycle and is a great source of energy. Danger exists if you continue to use fat because carbohydrates are unavailable. The body has many uses for fat other than providing a source of energy.

Starvation is near. The final source of energy is protein. The major source of protein that comprises your muscle tissue. In  severe loss of protein a very important organ can deteriorate. Your heart. Several important singers (Karen Carpenter for one) died from heart failure when the heart "muscle" was used as a food source.

Again, the glucose energy pathway has an entrance point for proteins to enter.

The body has to protect a means to seek food. The muscular system is of paramount importance. When muscle tissue is depleted to severe levels you can't move about to find food.

It is wise, in diabetes education to consider the pathways our bodies work to protect essential organs like the heart and brain.