A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

ACCELERATED APPROVAL: FDA regulations governing early marketing approval of promising drugs for life-threatening illnesses.

ACUPUNCTURE: a Chinese medical technique that involves inserting very thin needles into different acupuncture points on the body to improve the flow of Qi, or vital energy.

ACUTE RETROVIRAL SYNDROME (ARS): a combination of flu-like symptoms (e.g., fever, sore throat, skin rash, headache, nausea, muscle orjoint pain) that accompanies primary HIV infection or occurs shortly after infection.

ADHERENCE: following a prescribed treatment regimen, including correct dosage and number of doses per day, and taking with or without food.

AIDS DEMENTIA COMPLEX (ADC): mental impairment due to HIV infection that may be characterized by cognitive impairment, memory loss, mood and personality changes, speech and vision difficulties, and motor dysfunction.

AMENORRHEA: absence of menstruation or decreased menstrual flow.

AMNESIA: memory loss.

ANABOLIC STEROID: a natural or manufactured hormone (e.g., testosterone, oxandrolone) that promotes the synthesis of proteins and the building of muscle mass.

ANDROGEN: a hormone (e.g., testosterone, androsterone) produced by the testes and/or adrenal glands that has masculinizing effects.

ANERGY (adjective ANERGIC): the lack of an immune response to a foreign antigen.

ANOGENITAL: refers to area that includes the genitals and anus.

ANTAGONIST: a substance that blocks the activation of a specific cellular function by binding to a cell’s receptors. Also, a drug that blocks or reverses the action of another drug.

ANTIBODY (AB, IMMUNOGLOBULIN, IG): a protein secreted by activated plasma cells, which evolve from B-cells, in response to stimulation by an antigen.

ANTIGEN: any agent or substance (e.g., microorganisms or the substances they produce) that stimulates an immune response.

ANTIOXIDANT: a substance that inhibits an oxidation reaction by binding with and neutralizing free radicals and other highly reactive molecules, thus reducing oxidative damage.

ANTIRETROVIRAL: an agent that suppresses the activity or replication of retroviruses such as HIV.

APHASIA: lack of ability to speak or understand language.

APHTHOUS ULCER: a small, often painful shallow lesion on the mucous membranes of the mouth, esophagus or rectum.

APOPTOSIS: programmed cell death.

APRAXU: lack of normal motor control or inability to perform activities due to brain dysfunction.

ASIL: anal squamous intraepithelial lesion.

ASYMPTOMATIC: not feeling or showing outward signs of infection.

ATYPIA: a condition of being abnormal or not typical.

B

BACTEREMIA: the presence of bacteria in the blood.

BASELINE: a known value (e.g., baseline viral load) against which later measurements can be compared.

B-CELL (B-LYMPHOCYTE): an immune system cell that carries out the humoral (Th2) immune response. B-cells are produced in the bone marrow and mature into plasma cells that produce antibodies.

BILIRUBIN: a yellowish pigment released by red blood cells when they are broken down. An excess level of serum bilirubin is characterized by jaundice (yellowing of the skin and eyes), and may indicate stress on the liver.

BIOAVAILABILITY: the extent to which a drug is absorbed and circulated in the body.

BIOELECTRICAL IMPEDENCE ANALYSIS (BIA): a method of measuring lean body mass (muscle) and estimating cell mass.

BLOOD-BRAIN BARRIER: a physical barrier between the blood vessels and the brain that allows only certain substances to pass through.

BOB: "Brother of Bonzo," a cell-surface co-receptor that enables HIV to enter cells.

BODY CELL MASS (BCM): muscle and organ tissue.

BONZO (STRL33): a cell-surface co-receptor that enables HIV to enter cells.

BRANCHED-CHAIN DNA ASSAY (bDNA): a test for measuring the amount of virus (viral load) in blood plasma or tissue.

BREAKTHROUGH: a condition that has developed despite measures to prevent it. Also, a rise in viral load after it has fallen due to anti-HIV therapy.

C

CANCER: a malignant neoplasm or tumor which may invade surrounding tissues and/or spread to different sites.

CANDIDIASIS: a disease caused by a species of the yeast-like fungus Candida, usually C. albicans. Canadidiasis can affect the skin, nails and mucous membranes throughout the body including the mouth (thrush), esophagus, vagina, intestines and lungs.

CARCINOMA: a malignant tumor of the epithelial cells that line body surfaces and cavities. Carcinoma in situ refers to an early stage of cancer that has not invaded surrounding tissues.

CCR5: a protein found on certain blood cells that acts as a receptor site for chemokines.

CD4: a protein marker on the surface of certain types of T-lymphocytes and other cells. HIV uses the CD4 receptor to enter a cell.

CD4 CELL (CD4 LYMEPHOCYTE, T-HELPER CELL): a type of white blood cell that carries the CD4 surface marker and helps the body fight infection. CD4 cells engulf and process invaders (e.g., viruses) and release cytokines that coordinate a broad range of immune system activities.

CD8 CELL (CD8 LYMPHOCYTE): a type of white blood cell that helps regulate and/or carry out the body’s immune response. Two major subsets of T-cells express the CD8 surface marker: T-suppressor cells and cytotoxic T-lymphocytes (CTL).

CELLULAR IMMUNITY (TH1 RESPONSE): the immune response mediated by the Th I subset of CD4 cells. Cell-mediated immunity is stimulated by the cytokines IL-2, IL- 12 and gamma interferon, and carried out by cytotoxic T-lymphocytes (CTL) and macrophages.

CENTRAL NERVOUS SYSTEM(CNS): the brain and spinal cord.

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC): the U.S. federal agency within the Department of Health and Human Services that monitors disease occurrence and develops policies for preventing diseases and maintaining the health of the population.

CEREBROSPINAL FLUID (CSF): a clear, nutrient-rich fluid that circulates around and through the brain and spinal cord.

CHEMOKINE: a soluble factor secreted by certain immune system cells that stimulates the activity of other cells. Certain chemokines (e.g., MIP-1-alpha, MIP- 1 -beta, RANTES) have been shown to affect the activity of HIV; certain chemokine receptors (e.g., CCR5, CXCR4) are necessary for entry by HIV into cells.

CHINESE MEDICINE: an Asian system of healing that focuses on achieving internal balance. Practitioners use methods such as acupuncture, heat application (moxibustion), herbal preparations, food therapy, massage and exercise (Qi Gong or Tai Chi) to restore the flow of Qi (vital energy) and the balance of Yin and Yang.

CHLAMYDIASIS: an infection, usually sexually transmitted, with the bacteria Chlamydia trachomatis. Untreated chlamydiasis may lead to pelvic inflammatory disease and infertility.

CIRRHOSIS: a condition in which the liver becomes scarred, fibrous and filled with fat.

CLONE: a group of genetically identical cells or organisms derived from a single conunon ancestor.

COHORT: a group of individuals in a study who share a demographic, clinical or other statistical characteristic (e.g., age, study site).

COLPOSCOPY: examination of the tissues of the uterine cervix or the anal canal using a low powered, lighted microscope (colposcope) to identify abnormal cell growth.

COMPLEMENTARY AND ALTERNATIVE MEDICINE (CAM): any type of therapy not considered standard practice in a given culture. In most Western countries, CAM includes traditional Chinese medicine, homeopathy, naturopathy and chiropractic. Complementary therapy is typically used as an adjunct to standard therapy, while alternative medicine is used instead of standard therapy.

CONDYLOMATA ACUMINATA: genital and/ or anal warts caused by infection with a strain of the human papillomavirus.

CONTROLLED TRIAL: a clinical trial in which a group receiving an experimental therapy is compared to a control group that is not given the intervention under study.

CO-RECEPTOR: a second receptor required for entry into a cell or initiation of a biological process.

CORTICOSTEROID: an anti-inflammatory steroid hormone (e.g., prednisone, corticosterone) produced by the cortex of the adrenal gland or manufactured synthetically.

CROSS-RESISTANCE: the development of resistance to one agent (e.g., drug) which also confers resistance to another (often similar) agent.

CRYPTOCOCCOSIS: an infection caused by a yeast-like fungus. Cryptococcosis often manifests as cryptococcal meningitis, an inflammation of the membranes surrounding the brain and spinal cord.

CRYPTOSPORIDIOSIS: a disease caused by the protozoan Cryptosporidium parvum, which is most commonly transmitted to humans by contact with animal feces, ingestion of contaminated food or water, or oral-anal sexual contact.

CSIL: cervical squamous intraepithelial lesion.

CT SCAN: computed tomography a method of visualizing soft tissues of the body using x-rays.

CUTANEOUS: relating to the skin.

CXCR4 (FUSIN, LESTR): a co-receptor on the surface of certain T-cells that, along with the CD4 molecule, allows HIV to infect a cell.

CYP3A4: an enzyme that makes up part of the liver’s cytochrome P450 system.

CYTOCHROME P450 SYSTEM: a system that metabolizes drugs and other foreign substances in the liver by means of enzymes (e.g., CYP3A4) that inhibit or promote metabolic reactions.

CYTOKINE: an intercellular chemical messenger protein (e.g., tumor necrosis factor, interleukin) released by white blood cells. Cytokines facilitate communication among immune system cells and between immune system cells and the rest of the body.

CYTOMEGALOVIRUS (CMV, HHV-5): a herpes virus. In immunocomproniised individuals CMV may cause retinifis, pneumonia, colitis and/or encephalitis.

CYTOPATHIC: related to disease, disorders or destruction of cells.

CYTOTOXIC T-LYMPHOCYTE (CTL, T-KILLER CELL): an immune system white blood cell that targets and kills cells infected with micro-organisms.

D

DEMENTIA: chronic loss of mental capacity due to an organic cause.

DEMYELINATION: destruction or loss of the myelin (a fatty substance) sheath that surrounds and insulates the axons of nerve cells.

DESENSITIZATION: the reduction of sensitivity to an antigen or a drug, typically achieved by administering a small amount and gradually increasing the dose.

DISSEMINATE: to spread; a disseminated infection is one that is distributed throughout the body.

DNA (DEOXYRIBONUCLEIC ACID): a molecule found in the nucleus of cells that encodes genetic information. The particular sequence of 4 chemical building blocks (nucleotides) determines an individual’s unique genetic code.

DOSE-RANGING: a clinical trial in which different doses of a drug are compared to determine which dosage has the best balance of high efficacy and low toxicity.

DOUBLE-BLIND: a type of clinical trial in which neither the subject nor the investigator knows what treatment, if any, the subject is receiving.

DURA MATER: a membrane surrounding the brain and spinal cord.

DYSPLASIA: the abnormal development or growth of cells and tissues; precancerous

tissue changes.

E

EFFICACY: effectiveness; the ability to achieve a desired effect.

ELECTROCAUTERY: a method of destroying lesions or tissue using a high frequency electric current.

ELISA: enzyme-linked immunosorbent assay, a laboratory testforthe presence of antibodies in the blood serum.

ENCEPHALITIS: inflammation of the brain.any disease of the brain.

ENDOCRINE SYSTEM: a system of ductless glands that regulates bodily functions via hormones secreted into the bloodstream. The endocrine system includes the hypothalamus, pituitary gland, thyroid, adrenal glands and gonads (ovaries and testes).

ENDPOINT: a direct marker of disease progression, e.g., disease symptoms or death.

ENTERITIS: inflammation of the intestines, especially the small intestine.

ENZYME: a protein that induces or accelerates a chemical reaction.

EPITHELIUM: a thin layer of cells that covers the internal and external surfaces of the body, including body cavities,ducts and vessels.

EPSTEIN-BARR VIRUS (EBV, HHV-4): a herpes virus. EBV infection is common in children and may cause infectious mononucleosis in young adults; it is associated with oral hairy leukoplakia, lymphoid interstitial pneumonitis and some types of cancer in people with HIV disease.

ESOPHAGUS (adjective ESOPRAGEAL): the swallowing tube; the portion of the digestive canal between the oral cavity and the stomach.

ETIOLOGY (adjective ETIOLOGIC): the cause of a disease; the study of causes of disease

F

FAILURE TO THRIVE: a condition in which a child loses or fails to gain weight and grows at a slower rate than expected.

FOLLICULAR DENDRITIC CELL: a specialized immune cell in lymph nodes that traps and concentrates foreign antigens for recognition by lymphocytes.

FOOD AND DRUG ADMINISTRATION (FDA): the federal agency responsible for regulating the development, use and safety of drugs, medical devices, food, cosmetics and related products.

G

GASTROINTESTINAL: pertaining to the stomach and intestines.

GENE THERAPY: an approach to preventing and/or treating disease by replacing, removing or introducing genes or otherwise manipulating genetic material.

GENOTYPE (adjective GENOTYPIC): the specific genetic makeup or "blueprint" of an organism.

GINGIVITIS: gum disease; inflammation of the gums.

GONORRHEA: a sexually transmitted disease caused by the bacteria Neisseria gonorrhoeae. Gonorrhea may be asymptomatic or may include symptoms such as discharge, pelvic pain, and inflammation of the genitals, rectum and/or throat.

GPI20: a glycoproteinon the outer envelope of HIV that binds to the CD4 protein on the surface of certain cells.

H

HAART: highly active antiretroviral therapy, aterm for aggressive anti-HIV treatment usually including a protease inhibitor drug.

HALF-LIFE: the time required for half the amount of an agent (e.g., drug, virus, cell type) to be eliminated from the body.

HEMOPHILIA (person HEMOPHILIAC): a hereditary disease that prevents normal blood clotting, leading to easy bruising and potentially severe bleeding.

HEPATIC: relating to the liver.

HEPATITIS: an inflammation of the liver that may be caused by several agents, including viruses and toxins. Hepatitis is characterized by jaundice, enlarged liver, fever, fatigue and abnormal liver function tests. Hepatitis A virus (HAV) causes an inflammatory viral disease with a short incubation period. Hepatitis C virus (HCV) can cause chronic inflammation of the liver and may result in life threatening liver damage, cirrhosis and/or liver cancer.

HERPES SIMPLEX VIRUS (HSV-1, HSV-2): a herpes virus that causes blisters and recurring disease. HSV-1 usually produces lesions on the lips or in the mouth ("cold sores"); HSV-2 is usually sexually transmitted and generally produces lesions in the genital and/or anal area.

HERPES VIRUS: a group of viruses that includes herpes simplex virus types 1 and 2 (HSV- 1, HSV2), varicella-zoster virus (VZV, HHV-3), Epstein Barr virus (EBV, HHV-4), cytomegalovirus (CMV, HHV-5), human herpes virus types 6 and 7 (HHV-6, HHV-7) and Kaposi's sarcoma-associated herpes virus (KSHV, HHV-8).

HERPES ZOSTER (SHINGLES): a condition characterized by painful blisters that typically appear in a line ard is tribution on the skin.Shingles is caused by reactivation of a previous infection with the varicella-zoster virus (VZV) that initially causes chickenpox.

HORMONE: a chemical messenger involved in the regulation and coordination of cellular and bodily functions.

HUMAN PAPILLOMAVIRUS (HPV): a papovavirus. Many strains of HPV cause warts, including condylomata acuminata (genital warts). Certain strains (e.g., 16, 18) are associated with cervical, anal and oral cancer.

HUMORAL IMMUNITY (TH2 RESPONSE): the immune response mediated by the Th2 subset of CD4 cells. Humoral immunity is stimulated by the cytokines IL-4 and IL-10, and carried out by plasma cells (derived from B-cells), which produce antibodies.

HYDRATION: the replacement of body fluids by mouth or intravenously.

I

IMMUNE SYSTEM: the body's defense system that protects against foreign invaders (e.g., microorganisms) and cancerous cells. There are 2 branches: cell-mediated (Thl) and humoral (antibody based or Th2). Organs of the immune system include the lymph nodes, spleen, thymus, tonsils and bone marrow.

IMMUNIZATION: a process by which a person is protected against the adverse effects of infection by a disease-causing microorganism.

IMMUNODEFICIENCY: the inability of the immune system to work properly, resulting in susceptibility to disease.

IMMUNE GLOBULIN: see antibody.

IMMUNOMODULATOR (IMMUNE MODULATOR): a substance or other therapy capable of modifying functions of the immune system.

INCIDENCE: the number of new cases of a disease or condition in a specific population over a given period of time.

INDUCTION: the initiation phase of a particular therapy.

INTERFERON: one of a family of some 20 cytokines (messenger proteins) that play a role in immune response. Interferon-alpha is used as a treatment for genital warts and is under study for PML. A low-dose oral formulation of interferonalpha (Kemron) has shown little efficacy in clinical trials. Interferon-gamma is under study for certain AIDS-related opportunistic infections.

INTERLEUKIN (IL): a cytokine secreted by immune cells that regulate a range of immune system functions. IL-2 is produced by activated CD4 cells and promotes the proliferation and activity of CD4 cells, CTL and natural killer cells.

INTRAOCULAR: administered into the eye. An intraocular implant is embedded in the eye and releases a drug slowly over time.

IN VITRO: Latin for "in glass"; refers to work done in a test tube or culture medium in the laboratory.

IN VIVO: Latin for "in the body of a living organ refers to work done using human (or animal) subjects.

J

JC VIRUS: a human papovavirus thought to be the cause of progressive multifocal leukoencephalopathy.

K

KAPOSI’S SARCOMA (KS): an abnormal or cancerous proliferation of cells of the blood and/or lymph vessels causing tumors on the skin, mucous membranes and/or internal organs. KS typically appears as pink or purple, flat or raised lesions.

KAPOSI’S SARCOMA-ASSOCIATED HERPESVIRUS (KSHV, HHV-8): a recently discovered herpesvirus that is found in samples of tissue from Kaposi’s sarcoma lesions and may be a causal agent or co-factor.

KIDNEY STONE (NEPHROLITHIASIS): an accumulation of substances (e.g., minerals) in the kidney, which may lead to blockage and pain.

KILLER T-CELL: see cytotoxic T-lymphocyte.

L

LEAN BODY MASS: muscle and organ tissue.

LESION: any abnormal tissue change caused by disease or injury.

LIMIT OF DETECTION: the lower boundary of an assay (e.g., a viral load test). The limit of detection is the level below which a test cannot measure the presence of a component (e.g., HIV RNA).

LIPOSOME: a fat bubble suspended in a liquid used to carry drugs or other substances to cells or tissues, often resulting in fewer side effects than non-liposome drugs.

LIVER FUNCTION TEST: a blood test that measures levels of liver enzymes to indicate how well the liver is working and whether it might be inflamed or damaged.

LOG: refers to quantities in factors of 10. A log change is an exponential or 10-fold increase or decrease (e.g., going from 10 to 100 is a 1-log increase).

LUMBAR PUNCTURE (SPINAL TAP): the insertion of a needle into the spinal column to remove a sample of cerebrospinal fluid for diagnosis or to inject drugs.

LYMPHADENOPATHY: any abnormality of the lymph nodes. Usually refers to swollen and tender lymph nodes due to an infectious disease or lymphoma.

LYMPHATIC SYSTEM: a network of capillarylike vessels, ducts, nodes and organs that helps maintain the fluid environment of the body and coordinates immune responses. The lymphoid organs include the lymph nodes, spleen, thymus, tonsils and adenoids.

LYMPH NODE: a small, bean-sized organ located throughout the body. Lymph nodes filter out antigens and are the site of antigen presentation and immune activation.

LYMPHOCYTE: a type of white blood cell (e.g., T-cell, B -cell) responsible for immune defense.

LYMPHOMA: a malignant disease (cancer) originating in the lymph nodes.

M

MACROPHAGE: a large scavenger white blood cell that ingests degenerated cells and foreign particles and secretes messenger proteins (monokines) involved in a variety of immune system responses.

MALIGNANCY (adjective MALIGNANT): acancer, neoplasm or tumor that grows in an uncontrolled manner, invading nearby tissue and metastasizing (spreading) to other sites through the bloodstream.

MENINGITIS: an inflammation of the meninges, the membrane envelopes that encase the brain and spinal cord.

METABOLISM (adjective METABOLIC): the process of building the body’s molecular structures from nutrients (anabolism) and breaking them down for energy (catabolism).

METASTASIS (adjective METASTATIC): shifting of a disease manifestation from one site in the body to another, in particular the spread of cancer.

MICROBICIDE: an agent that inactivates, kills or destroys microbes.

MICROSPORIDIOSIS: infection with a protozoan parasite of the Microsporidia family (e.g., Enterocytozoon bieneusi, Septata intestinalis) which may affect the sinuses, lungs and intestines in immunocompromised patients.

MOLLUSCUM CONTAGIOSUM: raised, fleshcolored lesions with a central depression that contains active poxvirus. Lesions appear most often on the face, neck, arms, legs and anogenital region.

MONOCYTE: a large white blood cell that plays a role in immune defense by acting as a scavenger that destroys invading microorganisms. Monocytes circulate in the bloodstream; when they migrate to the tissues, they mature into macrophages.

MONONUCLEAR CELL: a cell that has a single nucleus, used to refer to a subset of white blood cells (e.g., lymphocytes, monocytes).

MONOTHERAPY: use of a single drug or other therapy.

MOXIBUSTION: the burning of the herb moxa (mugwort) near the body, often used in conjunction with acupuncture as an, element of Chinese medicine.

MRI: magnetic resonance imaging, a sensitive, noninvasive method for viewing soft tissues of the body using a strong magnetic field.

MUTATION: a change in the character of a gene that is perpetuated when a cell or virus divides.

MYCOBACTERIUM AVIUM COMPLEX (NMC): a disease caused by Mycobacterium avium or Mycobacterium intracellulare, bacteria found in soil and water.

MYELIN: a white fatty substance that forms the sheath around the axons of some neurons and provides insulation necessary for neural transmission.

MYOPATHY: an inflammation or disease of the muscles that may cause pain or weakness.

N

NAIVE: inexperienced. The term is used to describe an individual who has never taken a certain drug (e.g., AZT-naive), or to refer to undifferentiated immune system cells.

NATURAL KILLER CELL (NK CELL): a type of lymphocyte that attacks and kills tumor cells and cells infected with microorganisms.

NEOPLASIA: the disease process involved in the growth of a neoplasm.

NEOPLASM: a tumor or growth; tissue that develops abnormally or grows more rapidly than normal and lacks structural organization and functional coordination with normal tissue. A benign neoplasm (e.g., a wart) does not spread to other tissues; a malignant (cancerous) neoplasm has the potential to spread (metastasize) to other sites.

NEUTROPENIA: an abnormally low number or a decrease in the number of neutrophils, a type of white blood cell involved in defense against bacteria and fungi.

NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITOR (NNRTI): a drug (e.g., delavirdine, nevirapine) that binds to and inhibits the action of the retroviral reverse transcriptase enzyme, thus blocking viral replication.

NUCLEOSIDE ANALOG (NA): a compound (e.g., AZT, ddI, ddC, d4T, 3TC) that mimics one of the building blocks of DNA. These compounds suppress retroviral replication by interfering with the reverse transcriptase enzyme, the synthetic nucleosides cause premature termination of the viral DNA chain.

0

OLIGODENDROCYTE: a type of support cell in the brain that produces myelin.

ONCOGEN: an agent (e.g., virus, toxin) that is able to cause abnormal cell growth, or cancer. Oncogenesis is the development and growth of a neoplasm or tumor.

OPEN-LABEL: refers to a clinical trial in which both participants and investigators know what drug is being used.

OPPORTUNISTIC INFECTION (0I): a disease (e.g., PCP, MAC, CMV disease) caused by a microorganism that does not normally cause illness in a person with a healthy immune system, but which may cause serious disease when the immune system is suppressed.

ORAL HAIRY LEUKOPLAKIA: a condition characterized by white, raised lesions on the sides of the tongue and/or elsewhere in the mouth.

OXIDATIVE STRESS: increased levels of free radicals and other oxidation-promoting molecules that may result in cell membrane damage, cell death and damage to genetic material resulting in mutations.

P

p24 ANTIGEN: a protein fragment of HIV. The p24 antigen test measures the amount of p24 antigen in the blood or tissues.

PANCREATITIS: inflammation of the pancreas, a digestive gland in the abdominal cavity.

PAP SMEAR: a procedure in which a specimen of cells is taken from the uterine cervix or anus, prepared on a slide and examined under a microscope for abnormal cell growth.

PATHOGEN (adjective PATHOGENIC): any disease-causing agent, especially a microorganism.

PATHOGENESIS: the development of a particular disease, including the specific events involved, bodily tissues or systems affected, mechanisms of damage and timing of the course of disease.

PELVIC INFLAMMATORY DISEASE (PID): infection of the upper female reproductive tract including the uterus, fallopian tubes and ovaries.

PERINATAL HIV TRANSMISSION (PHT, VERTICAL TRANSMISSION): the transmission of HIV from mother to child. Perinatal transmission may occur in utero (in the womb), intrapartum (during birth) or postpartum (after birth, via breast-feeding).

PERIODONTAL DISEASE (PERIODONTITIS): an inflammatory disease of the gum tissues that surround and support the teeth.

PERIPHERALNEUROPATHY: a disorder of the peripheral nerves, usually involving the feet, hands and sometimes the legs, arms and face. Symptoms may include numbness, tingling or burning sensations, pain, abnormal reflexes, weakness and partial paralysis.

PHARMACOKINETICS: the action of drugs in the body, including the processes of absorption, metabolism, transformation, distribution to tissues and elimination.

PHASE I TRIAL: the first step in human testing of a new drug; these trials evaluate drug safety and toxicity at different dose levels in a small number of volunteers.

PHASE II TRIAL: the second step in the evaluation of a new drug in humans; these trials evaluate drug effectiveness and involve more participants than Phase I studies.

PHASE III TRIAL: the third step in human drug testing; these trials are designed to support and verify information gathered in Phase I and II trials, and involve many more volunteers. Phase III trials may compare the drug being tested to other dierapies or to placebo.

PHASE IV TRIAL: postmarketing studies done after a drug has been approved and offered for sale.

PHENOTYPE (adjective PHENOTYPIC): visible characteristics and/or behavior diat result from the interaction of an organism’s genetic "blueprint ‘(genotype) and the environment.

PHOSPHORYLATION: the addition of a phosphate group to a compound by an enzyme, an essential step in converting nucleoside analogs to compounds that can be used by cells.

PLACEBO-CONTROLLED TRIAL: a trial of an experimental therapy in which an inactive substance or mock therapy (placebo) is given to one group while the treatment being tested is given to another, and the results obtained in the different groups are compared.

PLASMA: the fluid, non-cellular portion of circulating blood.

PLATELET: a type of blood cell responsible for normal blood clotting.

PNEUMOCYSTIS CARINII PNEUMONIA (PCP): a life threatening type of pneumonia caused by a protozoan.

POLYMERASE CHAIN REACTION (PCR): a highly sensitive test that uses an amplification technique to detect small amounts of DNA or RNA in blood or tissue samples.

POSTEXPOSURE PROPHYLAXIS (PEP): drug therapy given immediately following exposure to an infectious organism in an attempt to prevent the infection from gaining hold in the body.

POST-HERPETIC NEURALGIA: pain along a nerve pathway that sometimes follows the healing of herpes zoster (shingles) lesions.

PPD TEST: a test that uses an injection of a purified protein derivative of tuberculin to test for prior exposure to Mycobacterium tuberculosis.

PREVALENCE: the number of individuals with a condition in a specific population.

PRIMARY HIV INFECTION (PHI): die initial introduction of HIV into the body; the earliest stage of HIV disease.

PRODRUG: an inactive form of a drug that exerts its effects after metabolic changes within the body convert it to a usable or active form.

PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATRY (PML): a rapidly progressing, often fatal brain disease believed to be caused by the IC papovavirus. PML infects oligodendrocytes and leads to deterioration of the brain’s white matter. Symptoms may include headache, changes in mental status, speech and vision difficulties, limb weakness and seizures.

PROPHYLAXIS (adjective PROPHYLACTIC): therapy that helps to prevent a disease before it occurs (primary prophylaxis) or recurs (secondary prophylaxis).

PROTEASE INHIBITOR: a drug (e.g., saquinavir, indinavir, ritonavir, nelfinavir) that blocks the action of the protease enzyme that breaks up large proteins produced from viral RNA, thereby preventing HIV replication.

PROTOZOA: a cellular or 1-celled microorganisms, several varieties of which can cause disease in humans.

Q

Ql (CHI, XI): the vital energy believed to be responsible for health and disease in traditional Chinese medicin

R

RADIOLOGY: the use of radiation (e.g., x-rays) to diagnose and/or treat disease.

RANDOMIZED TRIAL: an experiment arranged so as to produce a chance distribution of subjects into different treatment groups or arms.

RECEPTOR: a specific protein-binding site on a cell’s surface or interior. When chemicals bind to receptors, various cellular functions are activated or inhibited. Viruses enter cells by fusing with receptors on a cell’s surface.

RECOMBINANT: produced by genetic engineering.

RECURRENT: returning or occurring repeatedly.

REGIMEN: a formalized schedule by which drugs are administered, including the amount of drug and the number of doses in a time period.

RENAL: relating to the kidneys.

REPLICATION: duplication or reproduction.

RESERVOIR: a site where an infectious agent collects and multiplies (e.g., macrophages and lymph nodes are thought to be HIV reservoirs).

RESISTANCE: the ability of a microorganism to mutate in such a way that it loses its sensitivity to a drug.

RETINITIS: inflammation of the retina, the light sensitive tissue at the back of the eyeball.

RETROVIRUS: a class of enveloped viruses that have their genetic material in the form of RNA and use the reverse transcriptase enzyme to translate their RNA into DNA.

REVERSE TRANSCRIPTASE INHIBITOR (RTI): a drug that blocks retroviral replication by interfering with the reverse transcriptase enzyme. RTI include nucleoside analogs (e.g., AZT, ddl, 3TC) and non-nucleoside reverse transcriptase inhibitors (e.g., nevirapine).

RNA (RIUBONUCLEIC ACID): a single-stranded nucleic acid made up of nucleotides. RNA is involved in the transcription of genetic information.

RT-PCR: see polymerase chain reaction.

S

SALVAGE THERAPY: emergency treatment with an experimental drug of an illness that has not responded to standard therapy.

SECOND-LINE TREATMENT: the second preferred therapy for a particular condition.

SENSITIVITY: the ability of an organism to be affected by a drug or other agent.

SEROCONVERSION: the development of antibodies against a microorganism; the change in a person’s antibodystatusfromnegativetopositive.

SERUM: the fluid, non-cellular portion of blood; lymphatic fluid.

SET POINT: the level of viral load measured after seroconversion, when the initial burst of viral reproduction has subsided.

SEXUALLY TRANSMITTED DISEASE (STD): a disease (e.g., gonorrhea, syphilis, and chlamydiasis) that is transmitted through sexual contact.

SIDE EFFECT: an unwanted adverse reaction to a drug treatment (e.g., rash, nausea, peripheral neuropathy, bone marrow suppression, liver or kidney failure).

SINUSITIS: acute or chronic inflammation or infection of the paranasal sinuses (cavities behind the forehead and cheekbones).

SPLEEN (adjective SPLENIC): a lymphoid organ located in the abdominal cavity that stores and disposes of red blood cells and platelets.

SQUAMOUS INTRAEPITHELIAL LESION (SIL): abnormal cell growth and changes, particularly of cells at the squaino-columnar junction of the uterine cervix (CSIL) or anal canal (ASIL). Low-grade SIL is mild cellular atypia. High-grade SIL refers to more severe neoplasia or cancer.

STATISTICAL SIGNIFICANCE: the probability that an observed outcome of an experiment or trial is due to chance alone.

STEROID: a family of substances that share a similar chemical structure, including certain hormones (e.g., t6stosterone) and various drugs.

STRAIN: a specific genetic variant of an organism.

SUBCLINICAL: low-grade or asymptomatic.

SUBTYPE (CLADE): a distinct strain of a microorganism. There are at least 11 subtypes of HIV-I classified into 2 groups (M and 0).

SURROGATE MARKER: a marker or sign (e.g., viral load or CD4 cell count) that can serve in place of a clinical endpoint.

SYNCYTIUM (plural SYNCYTIA): a clump of cells whose membranes have fused to form a "giant cell." Strains of HIV are classified as either syncytia-inducing (SI) or non-syncytia-inducing (NSI).

SYNERGY (SYNERGISM): the action of 2 or more drugs working together to produce an effect greater than the combined effect of the same agents used separately.

SYPHILIS: a sexually transmitted infectious disease caused by the spirochete bacterium Treponema pallidum. Primary syphilis is characterized by non-painful chancre or sores in the mouth or anogenital area. Tertiary syphilis may lead to dementia and death.

SYSTEMIC: affecting the whole body; not localized.

T

TACHYCARDIA: very rapid heartbeat.

TAT: transactivator of transcription, a gene of HIV that plays a role in viral replication by regulating the transcription of viral DNA into RNA; also the protein produced by the tat gene.

T-CELL (T LYMPHOCYTE): a type of white blood cell derived from the thymus that participates in a variety of cell-mediated immune responses. There are 3 major types of T-cells: T-helper (CD4), T-suppressor (CD8) and T-killer (cytotoxic T-lymphocytes or CTL).

TOXICITY (adjective TOXIC): the quality of being poisonous or harmful; often used to refer to drug side effects.

TOXOPLASMOSIS: an opportunistic infection caused by the microscopic protozoan Toxoplasma gondii. A common manifestation is toxoplasniic encephalitis, characterized by brain swelling, dementia, confusion, lethargy, seizures and coma.

TRANSITION ZONE: the area of the uterine cervix or anal canal where squamous and columnar epithelial cells meet and overlap; a common site for squamous intraepithelial lesions.

TUBERCULOSIS (TB): an infectious disease caused by Mycobacterium tuberculosis that typically affects the lungs, but may also occur in other organs (extrapulmonary TB).

TUMORIGENESIS: the growth and development of a tumor, or accumulation of rapidly proliferating cells.

TUMOR NECROSIS FACTOR-ALPHA (TNF, CACHECTIN): a cytokine, produced by activated monocytes and macrophages, that can destroy tumors.

U

UNDETECTABLE: a term used to describe a viral load that is below the level of detection of the test being used.

URETHRITIS: inflammation of the urethra, the canal that carries urine from the bladder to the outside of the body.

V

VARICELLA-ZOSTER VIRUS (VZV, HHV-3): a herpes virus that initially causes chickenpox (varicella); VZV may lie dormant within the nerves and reactivate later to cause herpes zoster (shingles).

VIRAL LOAD: the amount of virus in the blood or other tissues. The presence of HIV RNA indicates that the virus is replicating. Changes in viral load may be used to gauge drug effectiveness and disease progression. Viral load is measured using assays such as the RT-PCR or branched-chain DNA (BDNA) tests.

VIREMIA: the presence of virus in the blood or plasma.

VIRUS: a minute organism that cannot grow or reproduce outside the body of a host. During replication a virus integrates its genetic material (DNA or RNA) into a host cell and takes over the cell’s biological mechanisms to reproduce new virus particles.

W

WASHOUT: the complete clearance of a drug from the body.

WASTING SYNDROME: a condition characterized by atrophy of lean body mass and involuntary weight loss of more than 10% of normal body weight.

WESTERN BLOT: a laboratory blood test for antibodies in the blood.

WILD-TYPE: the normal, typical form of a virus before antiviral therapy, genetic mutation in vitro replication takes place.

Z

ZINC FINGER ANTAGONIST: a type of antiretroviral drug (e.g., CI-1012). The name is based on the drug’s ability to bind to a protein involved in regulating the transcription of DNA to RNA. The protein itself is folded around a zinc ion in an arrangement that is shaped like a finger.