Data and Safety Monitoring Board (DSMB)
An independent committee of community representatives and clinical research experts who review data while a clinical trial is in progress to ensure that participants are not exposed to undue risk. A DSMB may recommend that a trial be stopped if there are safety concerns or if the trial objectives have been achieved, or can require changes to the study design to ensure safety of participants.

DAIDS
See: Division of Acquired Immunodeficiency Syndrome

Dementia
See:    AIDS Dementia Complex

Dendritic Cells
A type of antigen-presenting cell that picks up foreign substances from the bloodstream and "presents" them to other parts of the immune system, activating an immune response against the foreign invader.
See Also:   Antigen-Presenting Cell
                   Antigen

Deoxyribonucleic Acid (DNA)
Chemical structure that contains the genetic instructions for reproduction and protein synthesis for all cells and for many viruses.

Department of Health and Human Services (DHHS)
The U.S. government's principal agency for protecting the health of all Americans and for providing essential human services. DHHS includes more than 300 programs covering a wide spectrum of activities. Programs are administered by 11 operating divisions, including the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the National Institutes of Health (NIH). DHHS works closely with state and local governments, and many DHHS-funded services are provided at the local level by state or county agencies or through private-sector grantees.

Desensitization
Gradually increasing the dose of a medicine in order to avoid severe side effects. Desensitization procedures are sometimes used when administering some anti-HIV drugs and antibiotics.

DEXA
See: Dual Energy X-Ray Absorptiometry Scan

DHHS
See: Department of Health and Human Services

Diabetes
Also known as diabetes mellitus. A disease characterized by high levels of sugar in the blood (hyperglycemia). It can be caused by too little insulin (a hormone produced by the pancreas to regulate blood sugar), resistance to insulin, or both. Some anti-HIV drugs may cause or worsen diabetes.
See Also:   Hyperglycemia
                   Insulin Resistance

Diarrhea
Uncontrolled, loose, watery, and frequent bowel movements caused by diet, infection, medication, or irritation or inflammation of the intestine. Severe or long-lasting diarrhea can lead to weight loss and malnutrition. The most common infectious organisms causing HIV-related diarrhea include cytomegalovirus (CMV); the parasites Cryptosporidium, Microsporidia, and Giardia; and the bacteria Mycobacterium avium and Mycobacterium intracellulare. Bacteria and parasites that cause diarrheal symptoms in otherwise healthy people may cause more severe, prolonged, or recurrent diarrhea in people with HIV or AIDS.

Directly Observed Therapy (DOT)
A treatment strategy in which a health care provider or other observer watches a patient take each dose of a drug. This strategy is used with diseases like tuberculosis (TB) and HIV infection, where adherence is important for effective treatment and to prevent emergence of drug resistance.
See Also:   Adherence

Discordant Couple
A pair of long-term sexual partners in which one person is infected with a sexually transmitted infection (such as HIV) and the other is not.

Division of Acquired Immunodeficiency Syndrome (DAIDS)
A division of the National Institutes of Health's (NIH's) National Institute of Allergy and Infectious Diseases (NIAID). DAIDS was formed in 1986 to address the national research needs created by the HIV/AIDS epidemic; to increase basic knowledge of the pathogenesis, natural history, and transmission of HIV disease; and to support research to promote HIV detection, treatment, and prevention.
See Also:   National Institute of Allergy and Infectious Diseases
                   National Institutes of Health

DNA
See: Deoxyribonucleic_Acid

Dorsocervical Fat Pad
A type of lipodystrophy (problem in the way the body produces, uses, and distributes fat) in which fatty tissue builds up on the upper back and neck. It most often occurs in HIV-infected people as a result of PI or NRTI drug treatment. This fat buildup, also known as "buffalo hump," may also be associated with other metabolic side effects, such as high insulin levels.
See Also:   Lipodystrophy

Dose-Response Relationship
The relationship between the dose of a drug and its corresponding effect on the body. If a drug exhibits a dose-response effect, it means that as the dose increases, so does the effect.

DOT
See: Directly Observed Therapy

Double-Blind Study
A clinical trial design in which neither the participants nor the study staff know which individuals are receiving the experimental treatment and which are receiving a placebo (or another "control" therapy). Double-blind trials produce more objective results because the expectations of the study staff and the participants do not affect the outcome.
See Also:   Controlled Trial

DRESS
See: Drug Rash with Eosinophilia and Systemic Symptoms

Drug Antagonism
An interaction between two or more drugs in which one drug blocks or reverses the effect of another drug.

Drug-Drug Interaction
A change in the way a drug works when it is taken along with another drug. The effect may be an increase or a decrease in the action of either drug, or it may be a side effect that does not normally occur with either drug alone.

Drug Formulation
See:    Formulation

Drug Holiday
See:    Structured Treatment Interruption

Drug Interaction
An effect that can occur when one drug is taken with another drug or when the drug is taken with particular foods. Possible effects include changes in absorption from the digestive tract, changes in the rate of the drug's breakdown in the liver, new or increased side effects, or changes in the drug's activity.
See Also:   Drug-Drug Interaction

Drug Rash with Eosinophilia and Systemic Symptoms (DRESS)
A rare but life-threatening allergic drug reaction that sometimes occurs in people taking certain NNRTIs. Symptoms include severe rash along with fever, blood abnormalities, and organ inflammation.

Drug Resistance
The ability of some micro-organisms, such as bacteria, viruses, and parasites, to adapt so that they can multiply even in the presence of drugs that would normally kill them.

Drug Toxicity
See:    Toxicity

DSMB
See: Data and Safety Monitoring Board

Dual Energy X-Ray Absorptiometry Scan (DEXA)
A painless test that uses low energy x-rays to measure the mineral content of bones. DEXA scans are commonly used to test for osteopenia or osteoporosis, and are also used to evaluate lipodystropy.
See Also:   Osteopenia
                   Osteoporosis
                   Lipodystrophy

Dyslipidemia
Abnormal levels of fat in the blood, usually referring to abnormally high levels. Dyslipidemia may occur as a result of HIV infection or as a side effect of some anti-HIV drugs.
See Also:   Hyperlipidemia

Dyspnea
Difficult or labored breathing.