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o Unlocking blood’s secrets ne of the first mentions of blood as an important part of the body’s circulatory system may just be the Ebers Papyrus, a 16th century B.C. Egyptian medical writing that contains hundreds of prescriptions and remedies. The papyrus correctly connects the arteries to the heart, although it is mistaken in how the arteries carried air to the rest of the body. The ancient Egyptians didn’t understand that blood was the transport system. The second century Greek physician Galen was the one who realized that both arteries and veins carried blood, and he correctly theorized that the arterial blood transported air. He mistakenly believed, however, that arterial blood was created in the heart, while venous blood was created in the liver. Blood cells are actually created in bone marrow, in an ongoing process. Ibn al-Nafis, a 13th century Arabic physician, was the first to accurately record the process of blood circulation: Deoxygenated venous blood enters the heart’s right atrium, travels from there to the right ventricle and then through the pulmonary artery (the only artery to carry deoxygenated blood) into the lungs. Once the blood has picked up more oxygen, it moves into the cardiac veins and into the heart’s left atrium. From there it travels to the left ventricle and then the aorta, which feeds the blood into other arteries that carry the refreshed blood to the body’s various cells. This explanation remained largely unknown in Europe until 1628, when William Harvey published a book about the circulatory system after conducting a series of experiments. p The wonders of blood eople have been finding out more marvels about blood ever since. And the wonders keep mounting. Blood carries oxygen to all the cells in our body—a vitally important function, to be sure. But it also carries away carbon dioxide, ammonia and metabolic wastes. As the one tissue that comes in contact with every other tissue in the body, it also allows cells to communicate with one another—a communications network as well as a transport system. And it carries the first line of defense, our immune system, to wherever it’s needed. The task of carrying oxygen is done by the red blood cells, which make up about 40 percent of blood’s volume. As they mature, they give up their own nucleus and DNA in order to make room for hemoglobin, the proteins that can attach to the oh-so-necessary oxygen. These cells can squeeze through capillaries half their width by thinning down into threads and then crawling along the capillary wall. Dr. Andrew Schafer, 20 a professor at Weill Cornell Medical College, compares the process of their movement through capillaries to tank treads gripping the ground. The red cells are accompanied on their circuitous journey by white blood cells and platelets. These are the advance guards of the immune system. The white cells look for invading microbes that carry disease or infection. When they find something amiss, they release substances to “call” other white cells to the area. The cells then engulf the invaders or produce antibodies that make the Laura Rosen organisms easier to destroy. Red blood cells outnumber white ones by about 600 to 1. Blood is a fluid tissue that also thankfully has the ability to clot and become solid. And that’s where the platelets come in. Smaller than either red or white cells, the platelets run along the sides of the endothelium, the tissue that lines blood vessels. When they detect a break, they stick to it, attracting other platelets and forming a clump. If the break is too large for the platelets to control, they call in freefloating proteins that can cross-link to mend the break, creating a natural Band-Aid. All of these specialized cells float along in a plasma sea, the watery substance that comprises about 60 percent of blood. Plasma contains the sugars, proteins, salts and vitamins necessary to our cells. l The need for blood ooking at all those functions, it’s easy to understand how vital blood is to our well-being. Unfortunately, accidents, surgeries, disease and blood disorders can bring the need for more blood than our bone marrow can produce. According to America’s Blood Centers, more than 4.5 million patients need blood transfusions each year in just the United States and Canada. Hence there is an enormous need for people to donate blood. “Every 25 to 30 minutes, someone in Collier County receives blood or a blood product,” says Laura Rosen, community relations manager for the Community Blood Center (CBC), an affiliate of NCH Healthcare System. “Every donor counts because only three of every 100 people give blood.” The CBC came into existence some 60 years ago, after an Everglades City man had an accident. His friends traveled to Miami to donate blood. That first blood drive led to the realization that Collier County needed its own blood supply Naples Health | JULY-SEPTEMBER 2009 BLOOD FACTS Q Someone needs blood every two seconds. Q There are four main blood types: A, B, AB and O. Each can be positive or negative. AB is the universal recipient. O negative is the universal donor for red blood cells. Q Thirteen tests (11 for infectious diseases) are conducted on each unit of donated blood. Q If only one more percent of Americans donated blood, shortages would disappear for the foreseeable future. ARTIFICIAL BLOOD? Q Scientists have been exploring the idea of artificially created blood for decades. While some advances have been made, a safe and effective alternative has not been found. Q In 1957, Dr. Thomas Chang (then an undergraduate at McGill University in Montreal) began to research the creation of artificial red blood cells. His work helped scientists at Biopure to develop Oxyglobin, an artificial blood product that treats hemoglobin molecules with glutaraldehyde, a chemical that binds the molecules together. The company’s polyhemoglobin has been used to replace blood in aortic reconstruction surgery and to treat anemia patients in South Africa. It is awaiting FDA approval for use in the U.S. and donation facility. And that’s what continues to make donating blood locally so vital. “Where someone donates does make a difference,” Rosen says. “Most donors understand that giving blood helps to save lives, but it is also vital for people to question where their blood goes and who it benefits. Blood donors are a valuable community resource, so it’s important to stress that what is collected in this community by the Community Blood Center stays in this community to benefit local patients. Other centers come in periodically for blood drives, but they are not suppliers to our local hospitals.” The CBC draws blood from willing donors every day from Estero to Everglades City. Donors can come to either of the organization’s facilities (in the Medical Plaza Building in Naples and in the Bonita Sunshine Plaza), but the group also conducts drives at places where people are likely to be anyway—the Hollywood 20 theaters, for instance. Eligible donors are anyone who weighs at least 110 pounds, is 17 years of age or older and is in general good health. There is no upper age limit. Most common medications and the conditions they treat, such as high cholesterol or high blood pressure, do not prevent someone from donating. Individuals who have questions about their eligibility to donate are encouraged to contact their local donor center for clarification. If an individual is unable to donate, volunteers are always needed to help organize blood drives. The CBC endeavors to keep an adequate supply of blood for all the area’s needs, but Rosen reports it could use 75 to 100 more pints per week. “We can save three lives with just one pint,” Rosen notes. “All blood types are great, but we have the highest demand for O+ and O-.” To find out more about donating blood and keeping it within the community, visit www.givebloodcbc.org or call (239) 436-5455. Your donation can help someone’s marvelous transport system keep flowing the way it should. Naples Health | JULY-SEPTEMBER 2009 21