Glossary of Diabetes - C

C

C.D.E.

See: #Certified diabetes educator.

C-peptide

A substance the pancreas releases into the bloodstream in equal amounts to insulin. While being stored in pancreatic beta cells, proinsulin includes both insulin and C-peptide, which is freed before insulin secretion into the blood. Currently, since pharmaceutical insulin does not contain C-peptide, a C-peptide level test will show how much insulin the body is making. Insulin is prepared as two insulin molecules linked by a c-peptide. When insulin is secreted, C-peptide is released as well. It has in recent years been shown to have hormone properties, so far chiefly in connection with arterial vessel muscle tone. It has been shown to ameliorate some diabetic complications, such as neuropathy and microvascular damage. C-peptide varies much more between animal species than does insulin itself.

Calcium channel blocker

Calcium ions are used in many cells, including beta cells, as a signaling mechanism. Since it does not ordinarily pass through cell membranes, protein pores in cell membranes are used to provide a channel through which it can be 'pumped' -- an activity which requires energy if done against a concentration gradient. A Ca+ channel blocker is a drug which interferes with the operation of (some?) such channels. They have widespread effects, since Ca+ is used for many purposes in assorted tissues.

Callus

A small area of skin, usually on the foot, that has become thick and hard from rubbing or pressure as a result of increased production of surface skin (i.e., the topmost living cell layer); the callus itself is the result of this overgrowth and is itself a thickened 'dead cell surface layer'. Podiatry defines a callus as a skin lesion, and if it becomes cracked or internally separates, infection can follow, often with no warning signs. Calluses may lead to other problems such as serious infection. Shoes that fit well aid in reducing callus formation as they reduce localized rubbing and friction. Calluses are important risk factors for diabetics, in part because of changes in skin or vasculature characteristic of feet and lower legs in diabetics. See also: Foot care.

Calorie

a measure of the chemical energy in a specific amount of material. The food Calorie (resulting from combustion with oxygen from the atmosphere) is 1000x the calorie used in heat studies (i.e., in physics). Not all calories in food are actually usable. For instance, sawdust is largely cellulose (i.e., glucoses stuck together in long chains), and can be burned in a calorimeter (a common method of determining calorie content), but the human body contains no mechanism to convert it to its component glucoses for use as fuel. Calories relevant to diet (and so to diabetics) come only from those substances in food which can actually be used by the body. Thus, protein is not normally used for fuel, and so should not be counted as a food calorie in normal situations; nevertheless, it is usually taken into account. In a calorimeter (and in most diet references) all protein and carbohydrate is worth 4 calories/gram, while fat/oils are worth 9 calories/gram, and various alcohols and other (largely artificial) chemicals are worth fewer. A gram is about 1/25 of an ounce for those more familiar with English measures. The amount of usable calories in food is less than the amount measured in a calorimeter, and requires more care to determine. For instance, starch in plant foods is not readily available to be processed in digestion. Cooked starch (especially when cooked in the presence of moisture) is far more available digestively than raw starch (perhaps 60% vs nearly 100%).

Capillary

a very small blood vessel. At one end of a capillary is a connection to the body's arteries and at the other end of a capillary is a connection to the body's veins. It is in the capillaries that most gas exchange takes place (oxygen out of the blood into the tissues, and carbon dioxide into the blood). The reverse exchange happens in the capillaries of the lungs. Capillaries are controlled by very small muscles which, together, affect blood pressure very substantially. Those muscles are in turn controlled by, among other things, the presence or absence of insulin (and probably C-peptide) in the blood.

Capsaicin

a substance found in some plant products, especially hot peppers, which causes human nerves to report a hot sensation.

Carbohydrate

Any compound containing carbon, hydrogen, sometimes oxygen. There is considerable variety in these compounds and only some of them are available to humans as a fuel source. Cellulose, for instance, is a carbohydrate, but humans and all non-cud chewing animals (except termites and some microorganisms) can make no use of it. Only a few of the simple sugars (mono-saccharides) and even fewer of the di-saccharides (e.g., lactose) in food are available to humans. Others, if they contribute to human nutrition, do so after processing by intestinal bacteria (some estimates are that, in humans, less than 10% of caloric benefit comes from fermentation in the large intestine, as contrasted to other primates in which the proportion is rather larger). Most carbohydrates that can be absorbed and used for fuel by humans (e.g., starch and glycogen—both chains of glucose molecules).are eventually broken down to glucose during digestion. They eventually are part of the primary metabolic control mechanism. Fructose, on the other hand, is a carbohydrate which is neither; it is absorbed, but in humans processed only in the liver and in sperm, the only tissues which have the required enzymes. Ingested carbohydrate calories in non glucose forms are, in a special sense, invisible to the body. There has been recent speculation that the increase in such carbohydrates since sucrose (table sugar—half glucose and half fructose) became available in quantity after about 1700 with the discovery of a practical source (sugar cane), accounts for some of the diseases of civilization, including diabetes. Fructose had been quite rare in human diet until that time. Dietary fructose also characteristically causes alterations in blood lipid profiles, probably by changing liver operations.

Cardiologist

a physician with special training for treating heart and circulatory problems.

Cardiovascular

pertaining to the heart and vascular system (blood vessels).

Carpal tunnel syndrome

irritation and swelling of one of more of the nerves in the carpal tunnel in the wrist. Effects range from considerable pain to loss of strength or muscle control. The cause is thought to be mechanical, as in repetitive motion of the wrist joint as in typing while in inappropriate wrist positions.

Cataract

clouding of the transparent protein in the lens of the eye. A certain amount of this clouding occurs naturally during life. The elderly do not, therefore see quite the same way as they used to since there is a slight yellowish cast in the clouded lens. Diabetics have an increased risk for cataract since high levels of glucose cause reactions with assorted proteins, including those in the lens; many of the reaction products are not optically clear, nor pack in the same way, thus altering the shape of the lens. There are both acute (changes more or less rapidly with changes in blood glucose), and chronic (longer term, slower changing) lens shape changes in diabetics, making eye examinations -- for vision correction, for instance -- somewhat tricky.

Cerebrovascular disease

damage to the blood vessels in the brain, resulting in a stroke -- either ischemic (a blocked blood vessel) or hemorrhagic (i.e., a leaking blood vessel). People with diabetes are at higher risk of cerebrovascular disease.

Certified diabetes educator (C.D.E.)

a health care professional who is qualified by the American Association of Diabetes Educators to teach people with diabetes how to manage their condition. In the US, the health care team for diabetes should ideally include a diabetes educator, preferably a C.D.E.

Charcot foot

a foot complication associated with diabetic neuropathy that results in destruction of joints and soft tissue. Also called "Charcot's joint", "neuropathic arthropathy", and "neuropathic joint disease". Named for a Parisian physician Jean-Martin Charcot.

Chemical diabetes

is a term that is no longer used. See: Impaired glucose tolerance.

Chlorpropamide

a pill taken to lower the level of glucose (sugar) in the blood. Only people with Type 2 diabetes take these pills. They are inappropriate for Type 1 diabetics as they increase the beta cell output of insulin which is normally missing in Type 1 diabetics due to beta cell destruction; there is no insulin production to be increased. See also: Oral hypoglycemic agents. This is one of the sulfonylureas (Diabinese).

Cholesterol

a waxy substance related to the steroid chemicals which serves as a substrate for many things including cell membrane construction. It is also involved in the transport of fat (i.e., lipids) in the blood. The transport mechanism (Low Density Cholesterol or High Density Cholesterol particles) varies, and not only in density. HDL is associated with the scavenging of plaque on arterial walls, while LDL is associated with deposition of such plaque. High cholesterol levels are statistically correlated with vessel disease and with heart attack in most, but not all, human populations. Cholesterol is manufactured in the body and is absorbed from food in the diet. Furthermore, some diet elements seem to be connected with higher body production of cholesterol (e.g., saturated fat).

Chronic

present over a long period of time. Diabetes and arthritis are examples of chronic diseases as there is yet no cure for either.

Circulation

the structures and control mechanisms which manage blood circulation. It includes the heart, lungs, arteries, veins, and capillaries, as well as several physical mechanisms (e.g., the Starling's law response of heart muscle) and hormone mechanism (e.g., the renin to angiotension linkage between the kidneys, lungs, heart, and blood pressure).

Clinical trial

a study carried out in humans (generally using volunteers) to answer a question such as whether a new treatment (or drug or exercise technique) is effective or safe as treatment. In the US, studies are broken into Phase I, Phase II, and Phase III trials. A properly designed study is carefully controlled and designed to produce reliable information. A poorly designed study does not produce reliable information, though its 'results' are often widely cited for various reasons (including commercial ones). Distinguishing between these is difficult or impossible for the non-specialist, and even for many specialists. For diabetes, industry organizations (e.g., the American Diabetes Association) maintain review committees which evaluate the results of many studies relevant to diabetes.

Coma

unconsciousness. For a diabetic, coma can be caused by hypoglycemia or by diabetic ketoacidosis.

Comatose

in a coma; not conscious.

Complications of diabetes

harmful effects that may happen when a person has diabetes. Some acute effects, such as hypoglycemia or hyperglycemia, can happen any time and usually can be resolved quickly. Others develop when a person has had diabetes for a time (often years, or even decades). These include damage to the retina of the eye (retinopathy), blood vessels (angiopathy), the nervous system (neuropathy), or the kidneys (nephropathy). Multiple studies very clearly show that keeping blood glucose levels as close to the normal, nondiabetic range as possible does very significantly help prevent, slow, or delay the long-term complications of diabetes (e.g., eye, kidney, blood vessel, and nerve damage).

Congenital defect

problems or conditions that are present at birth.

Congestive heart failure

heart failure caused by loss of pumping power by the heart, resulting in fluids collecting in the body. If in the lungs, it is often called Chronic Pulmonary Edema.

Continuous subcutaneous insulin infusion (CSII)

See: Insulin pump.

Contraindication

A condition that makes a treatment not helpful or even harmful.

Controlled disease

taking care of oneself so that a disease has a reduced adverse effect on the body. People with diabetes can "control" the disease by staying on their diets, by exercising, by taking medicine if is prescribed, by regular exercise, and by monitoring their blood glucose. This care will help keep the glucose (sugar) level in the blood from becoming either too high or too low, reducing or eliminating acute problems, and if sustained over a long time, reduce the chance of chronic problems as well.

Conventional therapy

a system of diabetes management practiced by most people with diabetes who are treated by medically qualified personnel; the system consists of one or more insulin injections each day, daily self-monitoring of blood glucose, and a standard (or prescribed) program of nutrition and exercise. The main objective in this form of treatment is to avoid very high and very low blood glucose (sugar). Contrast w/ close control or intensive therapy. Also called: "Standard Therapy." See complications of diabetes.

Coronary disease

interference with the heart's blood supply, typically by clogging of coronary, or other, arteries. Ischemia means lack of oxygen which necessarily follows from one or more blocked arteries.

Coxsackie B4 virus

a virus which can trigger an auto-immune reaction which eventually results in a (mistaken) auto-immune attack on the beta cells. It is one of several such triggers, including other viruses. Some chemicals preferentially and directly attack the beta cells, and do not trigger the auto-immune attack (for instance a commercially used rat poison). If they are destroyed, the person becomes a Type I diabetic, no longer producing insulin internally.

Creatinine

a chemical normally found in the body. Its clearance rate by the kidney is a measure of renal function.

Cyclamate

a man-made chemical used instead of sugar in low calorie foods and drinks. Banned in the US (due to concerns about cancer risk increase in heavy users), not banned in Canada, Japan and the EU, even so. There are disagreements about the meaning of the clinical studies which caused concern.