Thoughts about Blood

Blood

ABOUT BLOOD

Blood is life. It is living tissue made up of cells suspended in a liquid called plasma. The three kinds of cells are red, white, and platelets. Together they make up about half of the blood volume; the other half is plasma containing nourishing proteins. Healthy bodies produce new cells every day. The amount of blood in each person depends on body size; for every 12-15 pounds of body weight, a human being has one pint of blood. After donating blood, the body replaces the fluid and white cells within 24 hours, and platelets and plasma proteins within 48-72 hours. The red blood cells are completely replaced in 4-6 weeks. Blood may be safely donated at 8 week intervals.

Red cells, mostly iron and protein, carry oxygen to the body tissues on a protein called hemoglobin, which gives this cell its red color. White cells fight infection and disease. Platelets, like white cells, are made in the bone marrow; they help clot blood when bleeding occurs. Plasma, made in the liver, carries nutrients to all the cells in the body, transports waste products to the kidneys for excretion, and participates in blood clotting.

Everyone's blood has certain physical characteristics that can be described, just like hair and eye color, or height. Blood is described by how it looks in the laboratory. There are four major blood types: A, B, AB, and O. Blood type is identified by a series of "markers" on the surface of the red blood cells. These are inherited from one's parents in the same way that other genetic traits are passed along. There is an A marker, denoting type A blood, and a B marker for type B. The presence of both markers indicates type AB blood and the absence of both means type O. At another red cell site, there may be a marker indicating Rhesus factor. Like the ABO type markers, the Rh type is inherited from one's parents. Presence of marker denotes "Rh positive," while its absence means "Rh negative" blood. Only about 15% of Caucasians are Rh negative, while only a few Orientals (1%) are Rh negative. In Hawai'i Rh negative blood is much harder to find when it is needed.

Blood Groups by Percent
International				Among U.S. Population
O	A	B	AB	O+	37.4%	A-	6.3%
43	40	12	5	A+	35.7%	AB+	3.4%
O+	A+	B+	AB+	B+	8.5%	B-	1.5%
38.2	33.3	10.0	3.5	O-	6.6%	AB-	0.6%
O-	A-	B-	AB-	(figures are rounded) [sources: Blood Bank of Hawaii, Blood Bank of Rhode Island, Blood Bank of San Diego]
6.5	6.0	2.0	0.5

Among Races in Hawai'i's Population	O	A	B	AB
--all races	39	38	17	6
Caucasian	45	40	10	4
Chinese	42	27	25	6
Filipino	44	22	29	6
Hawai'ian	46	46	5	3
Japanese	31	39	21	10
Korean	32	28	30	10

Blood may only be given to another person if it is of the correct type. Blood that is transfused must not have any markers that are not already carried on the recipient's red blood cells. If this were to happen, the receiving body would recognize the new blood as "foreign" and reject it. Therefore, type A blood can only be given to people with blood type A or AB. Type B blood can only be given to people with blood type B or AB. While type AB blood can be given only to people who already have type AB blood, type O blood can be given to anyone. Likewise, Rh negative blood can be given to anyone, but Rh positive can only be given to people who are Rh positive blood. Tracing through it again, it can be seen that O- blood is the universal donor but exclusive recipient, whereas AB+ is the universal recipient but exclusive donor.

[sources: Blood Bank of Hawaii, Blood Bank of Rhode Island, Blood Bank of San Diego]

STANDARDS
[sources: Blood Bank of Hawaii; The Walking Magazine, OCT/NOV 88, p.34]	Excellent	Normal	Poor		minimum acceptable to donate blood	see your doctor
Pulse (rest)	50-60	60-80	50-100		< 80
BP: systolic	100-120	130-140	90-180		< 140	> 140
diastolic	60-70	70-80	50-100		< 80	> 90
temperature				97.6 - 99.6^oF
cholesterol	< 180	180-200 mg/dL				> 220
blood iron: (female)	Hgb	12.5-16 gm			10.0 gm
blood iron: (female)	Hct	38%			31%
blood iron: (male)	Hgb	13.5-18 gm			11.5 gm
blood iron: (male)	Hct	41%			35%

Body Works (25) from the Toronto " Globe and Mail" on May 10, 1995

What's in your blood

This week, Red Cross officials will make their appearance before the federal inquiry trying to determine how more than 1,000 Canadian hemophiliacs and transfusion patients contracted the AIDS virus. Here's what you should know about the fluid that keeps you alive.

BY WALLACE IMMEN the Globe and Mail

BLOOD, as we know, is thicker than water, twice as thick in fact. And it's also heavier, because it contains four million to six million red blood cells per cubic millimetre. This makes blood about 8 or 9 per cent of our body weight.
If you divide the blood into its liquid and solid components, as blood banks regularly do to make it easier to store and use in transfusions, its complex structure becomes easier to understand.

Among the solids, red blood cells (also known as erythrocytes) are by far the most numerous and play the most demanding role, because they carry oxygen to the body's cells. Any cell that doesn't get a continuous supply of oxygen would die within a few minutes.

If seen under a microscope, the red cells look like jelly doughnuts whose centres have collapsed, a design that makes them flexible enough to change shape as they make high-speed twists and turns through the tiniest of arteries.

The red colour comes from the iron-bearing protein hemoglobin, which gives each cell the capability of absorbing up to a million molecules of oxygen on each pass through the lungs.

Blood is brighter red when it's full of oxygen after coming from the heart and paler after it has released oxygen during its circulation and is returning to the heart, says Dr. William Ferancomb of the blood-transfusion laboratory of Toronto Hospital.

Leukocytes, or white blood -cells, represent less than 1 percent of the solids, but they are the blood's defenders, responsible for locating and removing viruses and bacteria as well as toxic materials and malformed cells. A healthy immune system has a white-cell count of 4,000 to 11,000 leukocytes per cubic millimetre.

The remainder of the solids consist of the blood's emergency patch kit to plug up any hole that forms in blood vessels. Platelets, which are brownish yellow, fill the wound and start the coagulation of cells into a clot that keeps it closed until repairs are complete. Leakage of blood from a wound means loss of oxygen to cells, so speed is critical; clotting starts to work within seconds of an injury and can close a wound in a matter of minutes. After the breach is healed, an enzyme called plasmin starts to dismantle the clot by slowly dissolving it.

Plasma, the liquid part of blood, can be easily separated from the heavier solids. In a blood bank, the solids are treated with anticoagulants and kept for about 35 days, while plasma can be frozen and stored indefinitely.

Metropolitan Life Desirable Weight Table
height	men	women
4' 9"		90-118
4 10		92-121
4 11		95-124
5 0		98-127
5 1	105-134	101-130
5 2	108-137	104-134
5 3	111-141	107-138
5 4	114-145	110-142
5 5	117-149	114-146
5 6	121-154	118-150
5 7	125-159	122-154
5 8	129-163	126-159
5 9	133-167	130-164
5 10	137-172	134-169
5 11	141-177
6 0	145-182
6 1	149-187
6 2	153-192
6 3	157-197

Plasma contains more than 100 different materials, and most important in medical treatments are its proteins:

Albumin, which helps keep a balance of fluid in the tissues, can be isolated and stored until needed for injection to prevent shock in people who have become dehydrated or have lost a lot of blood.
Gamma globulins are also proteins and carry the antibodies produced by specialized cells that support our immune responses.
Proteins known as Factor 8 and Factor 9, which aid coagulation of blood, can be separated from plasma and used to treat hemophiliacs, whose blood lacks these proteins.

Hormones also travel in the plasma, and in that sense there is male and female blood. Blood from a male will contain more testosterone and women's blood has more estrogen. But the amounts of hormone a recipient gets in a medical treatment isn't large compared with the amount in the body.

Normally, a red cell lives for 100 days and each day 1 per cent of the total die and are replaced with fresh cells from the marrow of bones such as the ribs, vertebrae and pelvis, where immature cells are held in storage until the body needs them to replace worn-out cells.

Scientists have known that an enzyme is responsible for keeping the balance between red-cell death and production and that it can speed up replacement if you've lost blood.

But last month, scientists reported that they had found a separate enzyme that slows down red-cell production when the body has enough to prevent the blood from getting too thick to flow freely.

Mixability guide

In a blood transfusion, it's important that the blood of the donor be compatible with the blood of the recipient. Otherwise, an immune reaction can result in a breakup of the cells, which can be fatal.

Type O doesn't cause a reaction if it is given in transfusion to any other blood types. However, a Type O can receive only Type O blood without reaction.

Type A blood reacts to Type B as an invader but accepts both O and A.

Type B is unfriendly to A but accepts O and B.

Type AB will co-exist with any blood type, but will react if transfused to someone with any other blood type.

The Rh factor, which began as an abbreviation of rhesus monkeys, in which it was first discovered, refers to a sensitization of the immune system. Most people are Rh positive. The 10 to 15 per cent of the population that has Rh negative blood would produce antibodies to Rh positive blood if they received it in a transfusion. For these people, the next encounter with Rh positive blood causes an immediate immune reaction. In pregnancy, such a reaction could cause brain damage to the baby.

Body Works appears each Wednesday.

You can read some peculiar additional information about my blood.

"The life of the creature is in its blood" Leviticus 17:11

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