AIDS Glossary

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AIDS Glossary

p.: pharmaceutical abbreviation, after (post)
p.c.: pharmaceutical abbreviation, after meals (post cibum)
p.o.: pharmaceutical abbreviation, taken by mouth
p.r.n.: pharmaceutical abbreviation, as necessary (pro re nata)
p24: a core protein of HIV produced by the gag gene.
p24 antibody: antibodies produced in response to the presence of p24 antigen of HIV. The p24 antibody test measures the level of p24 antibodies in the blood. High levels of p24 antibody in the absence of p24 antigen may indicate that the immune system is successfully suppressing the virus.
p24 antigen: protein fragment (nucleocapsid) of HIV. At one time, p24 antigen was considered a surrogate marker for disease progression. Today, scientists know there are long-term non-progressors with high p24 lab readings. Others have died of AIDS without ever showing any p24 antigen.
p450: see cytochrome P450 system.
paclitaxel (taxol): a drug derived from the yew tree that is used to treat certain types of cancer (e.g., ovarian cancer). Paclitaxel works by inhibiting cell division, and is under study for the treatment of Kaposi's sarcoma.
palliative: offering symptomatic relief and comfort care (e.g., alleviation of pain) rather than a cure.
palpitation: pulsation of the heart, usually with an increase in force or frequency of the heartbeat.
panacea: a miracle cure-all.
pancreas: a gland lying behind the stomach that creates insulin and pancreatic juice -- a clear, alkaline containing enzymes used during digestion.
pancreatitis: potentially fatal inflamation of the pancreas. Pancreatitis is a side effect of some anti-HIV drugs. Symptoms include severe stomach pain.
pancytopenia: low levels of all types of blood cells.
pandemic: a widespread disease outbreak affecting the population of an extensive area of the world. See also epidemic.
papanicolaou smear (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 (dysplasia). An abnormal Pap smear suggests increased risk of developing cancer.
papillomavirus: see human papillomavirus.
papovavirus: a type of virus that can cause neoplasms (e.g., warts, cancer).
papule: a small raised bump on the skin or mucous membrane.
para-: prefix, beside, near.
paracoccidioidomycosis: a fungal infection endemic to South and Central America. The disease develops in the lungs and may become chronic in immunosuppressed individuals.
paradigm: a theoretical framework that forms the basis for hypotheses and explanations.
parallel track: a system of making experimental drugs available to individuals who are ineligible for or unable to participate in clinical trials. Parallel track drugs have completed Phase I safety testing and show enough evidence of efficacy to merit wider release.
paranasal sinus: an air-filled cavity within the skull; there are 4 sets of paranasal sinuses: frontal, maxillary, sphenoidal and ethmoid.
paraplegia: paralysis of both legs and the lower part of the body. See also quadriplegia.
parasite: an organism that grows and feeds in or on another organism without benefiting the host organism. Most parasites are harmless, but some are deadly. The most common ways of getting a parasitic infection are from contaminated water and rimming (oral-anal contact).
parasympathetic nervous system: a branch of the autonomic nervous system that tends to induce secretion, increase the tone and contraction of smooth muscle, and cause dilation of blood vessels.
parenchyma: the internal functional tissues of an organ, as opposed to supporting or structural tissues.
parenteral: given by injection, bypassing the enteral (gastrointestinal) tract.
parenteral nutrition: a regimen that delivers nutrients intravenously, bypassing the gastrointestinal tract. Partial parenteral nutrition (PPN) delivers some nutrients orally and some intravenously; total parenteral nutrition (TPN) delivers all nutrient intravenously, typically into a large central vein via a chest catheter.
paresthesia: abnormal physical sensations such as prickling or tingling.
parkinson's disease (parkinsonism): a chronic progressive nerve disease characterized by muscle tremors, weakness, rigid movements, halting gait, drooping posture and expressionless facial appearance.
paromomycin (humatin)
LINKS: ....Medical Dictionary ....Stress Management ....Brain Food ....Bird Flu Info ....AIDS/HIV ....Your Memory Enhancer ....Brain Facts ....Neurotech ....Success Tips ....World Travel Guide ....Boston Tour Guide ....Dynamic South Korea ....Makeup.Fashion ....Allergy Info: an antibiotic used to treat intestinal infections such as amebiasis and giardiasis, and under study as a treatment for cryptosporidiosis.
paronychia: inflammation and separation of the skin from the base of the nails.
parotitis: inflammation of the parotid gland, the largest of the salivary glands.
partial parenteral nutrition (ppn): see parenteral nutrition.
parvovirus: a family of viruses, several species of which infect humans, including the adeno-associated viruses which are used as vectors in biotechnology. Parvoviruses tend to infect rapidly growing tissues. Symptoms include fever, malaise and possibly skin rash.
passive hyperimmune therapy (pht): an experimental treatment for HIV infection that involves monthly infusions of p24 antibody-rich plasma (hyperimmune plasma) from asymptomatic healthy HIV positive donors to patients with advanced HIV disease.
passive immunity: immunity acquired by transfer of antibodies, either naturally (e.g., from mother to fetus) or by injection. Contrast with active immunity.
passive immunization (passive immunotherapy): the introduction of exogenous antibodies (gamma globulins) to treat disease, for example from an individual with active immunity, or of genetically engineering antibodies. Contrast with active immunization.
pasteurization: partial sterilization of a substance (especially a liquid) using heat to destroy harmful organisms without inducing major chemical alteration of the substance.
pastille: a lozenge; a medicated disc or tablet dissolved in the mouth.
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.
pathogenicity: the property of being able to cause disease.
pathology (adjective pathologic): the study of disease, focusing on causes, development and progress of disease, and how the body is affected.
pbmc: see peripheral blood mononuclear cell.
pcg.: pharmaceutical abbreviation, picogram
pcp: abbreviation, pneumocystis carinii pneumonia. a fungal inflamation of the lungs. PCP was once the leading cause of death of people with HIV Disease. Today it is still dangerous but is often treatable and preventable.
pcr: see polymerase chain reaction.
peak level: the highest concentration of a drug achieved in the body.
pediatrics: the medical specialty concerned with the development, care and treatment of children from birth through adolescence.
pediculosis: lice infestation.
pelvic exam: examination of the organs of the female reproductive system. A speculum is used to open the vagina and aid in visualizing the uterine cervix; a sample of cells may be taken for a Pap smear or laboratory culture. The uterus and ovaries are palpated (felt with the fingers) to detect swellings or other abnormalities.
pelvic inflammatory disease: ##### (This is considered an AIDS-defining condition in the United States.)
pelvic inflammatory disease (pid): infection of the upper female reproductive tract including the uterus, fallopian tubes and ovaries. PID is often the result of untreated chlamydiasis or gonorrhea. Symptoms include pain, fever and vaginal discharge. Without treatment, PID can become chronic and severe and may lead to scarring, infertility, ectopic pregnancy, septicemia and death. See also salpingitis.
penicillin: an antibiotic drug used to treat various bacterial infections. Penicillin G is a strong form of penicillin used to treat neurosyphilis.
pentamidine (pentam, nebupent): a drug used to prevent and treat Pneumocystis carinii pneumonia. Intravenous pentamidine is used to treat severe cases of PCP, especially in patients who cannot tolerate TMP-SMX. Aerosolized pentamidine is used as a prophylaxis against PCP. Side effects may include pancreatitis.
pentoxifylline (ptx, trental): a drug used to treat circulatory problems. PTX increases the production of interferons and reduces levels of tumor necrosis factor (TNF) in the body.
peptic ulcer: a lesion in the stomach wall caused by infection with the bacterium Heliobacter pylori.
peptide: a short chain of amino acids linked by peptide bonds; longer chains are generally called proteins.
peptide t: a peptide composed of a sequence of 8 amino acids. Peptide T is under study as therapy for HIV-related dementia and peripheral neuropathy.
percutaneous: through the skin.
perianal: refers to the area surrounding the anus.
pericarditis: inflammation of the pericardium, the membrane that surrounds the heart.
perinatal: refers to the period around the time of birth.
perinatal hiv transmission (pht): the transmission of HIV from a mother to a fetus or infant. An estimated 10-40% of mothers transmit HIV to their offspring; AZT has been shown to significantly reduce the risk of PHT. See also vertical transmission.
periodontal disease (periodontitis): an inflammatory disease of the tissues that surround and support the teeth. Periodontal disease may begin as gingivitis and progress to more serious gum disease accompanied by erosion of the gums and bone supporting the teeth.
peripheral: pertaining to or located at the periphery or away from the center.
peripheral blood mononuclear cell (pbmc): a single-nucleus white blood cell (e.g., monocyte) that circulates in the blood. See also mononuclear cell.
peripheral nervous system: part of the central nervous system that includes cranial nerves, spinal nerves, and the sympathetic nervous system.
peripheral nervous system (pns): the portion of the nervous system outside of the brain and spinal cord; nerves that run from the spinal cord to the rest of the body.
peripheral neuropathy: any disease, inflamation, or abnormality of the peripheral nervous system. This is considered an AIDS-defining condition in the United States.
peritoneum: the thick membrane that lines the abdominal cavity and covers the visceral organs. The peritoneal cavity is the space between the outer and inner layers of the peritoneal membrane.
peritonitis: inflammation of the peritoneum.
persistent generalized lymphadenopathy (pgl): a condition in which the lymph nodes are chronically swollen in more than one area of the body for a prolonged time, sometimes accompanied by a swollen spleen.
pet scan: see positron emission tomography.
pgl: see persistent generalized lymphadenopathy.
ph: a logarithmic scale used to describe the acidity or alkalinity of a solution; a measure of the hydrogen concentration of a solution. Water has a neutral pH of 7. A pH below 7 is acidic; a pH above 7 is alkaline (or basic).
phagocyte: a scavenger white blood cell (e.g., neutrophil, basophil, eosinophil, monocyte, macrophage) that engulfs and destroys dead cells, bacteria and other debris. Once the foreign matter is ingested, phagocytes produce toxic chemicals (e.g., hydrogen peroxide) to kill the invader.
phagocytosis: the process of engulfing and destroying matter (e.g., microorganisms, dead cells) carried out by phagocytes.
pharmaceutical: refers to the development and manufacture of drugs.
pharmaco-: prefix, related to drugs or medicine. A NAME=pharmacodynamics
pharmacodynamics: The study of drug activity.
pharmacokinetic trials: a clinical trial of an experimental drug that concentrates on the body's ability to absorb the drug. Blood tests are commonly given every few minutes or hours during a pharmacokinetic trial.
pharmacokinetics: The study of drug absorption and metabolism.
pharmacology: the science of drugs, their sources and how they work; the specialty of preparing and dispensing drugs.
pharmacotherapy: the use of drugs to treat disease.
pharyngitis: pain and inflammation of the pharynx (throat).
pharynx (adjective pharyngeal): the throat; the upper part of the gastrointestinal tract between the oral cavity and the esophagus.
phase i clinical trial: the first clinical trial of an experimental drug, desined to evaluate toxicity (adverse reactions) at various dosing levels. Most phase one clinical trials have only a small number participants. Phase I clinical trials are part of the U.S. FDA approval process. (also see double-blind, and open label trial.)
phase i trial: the first stage of human testing of a new drug. Phase I trials evaluate drug pharmacokinetics, safety and toxicity at different dose levels, typically in a small number (less than 100) of healthy volunteers.
phase ii clinical trial: the second clinical trial of an experimental drug, designed to evaluate the drug's effectiveness in humans. Drugs that fail phase one never make it to phase two. This second clinical trial usually involves 300 or fewer volunteers. Phase II clinical trials are part of the U.S. FDA approval process.
phase ii trial: the second stage of the evaluation of a new drug in humans; these trials evaluate drug efficacy, involve more participants (often several hundred) and typically last longer than Phase I studies. Phase II trials may be divided into Phase IIa (pilot trials in patients with the disease to be treated) and phase IIb (well-controlled efficacy trials). Typically Phase II trials are done only if Phase I trials have shown the drug to be safe, but sometimes Phase I and Phase II studies are combined.
phase iii study: the third and final clinical trial of an experimental drug. This third stage in a new drug's approval process expandes the test to several thousand volunteers. The purpose is to evaluate the drug in a larger population to make sure the results of the first two phases hold true in a larger base. Problems involving drug interactions commonly surface during this third stage. Phase II clinical trials are part of the U.S. FDA approval process.
phase iii trial: the third stage of human drug testing; these trials are designed to verify and extend the information gathered in Phase II trials, and involve large numbers of participants (several hundred to several thousand). Phase III trials may compare the drug being tested to other therapies or to placebo. Phase IIIa trials are conducted prior to the filing of a new drug application (NDA); Phase IIIb trials are conducted after an NDA is submitted.
phase iv trial: postmarketing studies done after regulatory approval has been granted and the drug has been offered for sale. These trials provide additional information about safety and efficacy in large numbers of patients under "real world" conditions of use.
phenotype: visible characteristics and/or behavior that result from the interaction of an individual's genetic "blueprint" (genotype) and the environment. Contrast with genotype.
phosphorylation: the addition of a phosphate group to a compound by an enzyme (e.g., thymidine kinase, tyrosine kinase). Phosphorylation is an essential step in many cellular processes.
photodynamic therapy (pdt): a form of cancer treatment in which a patient is exposed to light (e.g., ultraviolet light, light from a laser) after ingesting a light-sensitive chemical (e.g., hematoporphyrin), which accumulates in tumor tissue.
photophobia: excessive sensitivity to light.
photosensitivity: an increased sensitivity to light, which may lead to easy sunburning and other adverse effects. Photosensitivity is a side effect of some drugs (e.g., dapsone, hypericin).
phototherapy: treatment using light, typically ultraviolet light.
pht: see passive hyperimmune therapy, perinatal HIV transmission.
physicians' desk reference (pdr): a book of prescription drugs and their indications for use.
pi: see principle investigator, protease inhibitor.
pico-: prefix, one-trillionth
pid: see pelvic inflammatory disease.
pigment: organic coloring matter; the chemicals in the skin, eyes, etc. that give a particular color.
pituitary gland: a small gland in the brain that produces several hormones that regulate bodily functions via the action of other endocrine glands.
placebo: an inactive substance given to a control group in a clinical trial. This placebo is sometimes called a sugar pill because some of these control groups are given common substances, such as sugar, disguised as medication.
placebo effect: a change (e.g., a reduction in symptoms) that is attributable to the treatment process itself as opposed to the therapeutic value of the agents or therapies used, most likely due to the expectations of the patient.
placebo-controlled clinical trial: a clinical trial in which one group of volunteers is given the experimental drug, and the other group is given a placebo. The results of the two groups is compared to see if the experimental drug was effective compared to the placebo. In many HIV-related clinical trials, some approved treatment is used instead of a placebo.
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 under study is given to another; the results obtained in the different groups are then compared. Placebo is used to make the experience of the treatment and control group as similar as possible and to minimize bias due to the expectations of the patient or investigator. Contrast with uncontrolled trial.
placenta: the vascular organ that connects the fetus and the mother's uterus, through which metabolic exchange between the fetus and mother occurs. Some pathogenic organisms and maternal antibodies may be transferred across the placenta.
plasma: the fluid, non-cellular portion of circulating blood that carries blood cells and nutrients throughout the body, removes metabolic wastes and is a medium for chemical communications between different parts of the body. See also serum.
plasma cell: a type of blood cell that produces antibodies. Plasma cells develop from B-cells in response to stimulation by an antigen.
plasmapheresis: the selective removal of components from the blood plasma, after which the plasma is returned to the person from which is was taken.
plasmid: a piece of genetic material that exists outside the chromosomes in the nucleus of a cell. Genetically engineered plasmids are often used in biotechnology.
platelet: a small blood cell (protoplasmic disk) involved in coagulation and wound healing. HIV can lower a person's platelet count, causing severe bleeding. The normal platelet count is 200,000 to 300,000.
plenary: a meeting, usually part of a large conference, that is open to all participants.
pleura: the linings of the lung.
pleurisy: swelling of the linings of the lung (e.g., due to pneumonia, lung cancer) characterized by pain and shortness of breath.
pleuritis: inflammation of the pleura, or linings of the lung.
pluripotent stem cell: a hematopoietic cell in the bone marrow that is capable of differentiating into any type of blood cell.
pmea: an experimental nucleoside analog drug that may have activity against herpesviruses and HIV.
pml: abbreviation, progressive multifocal leukoencephalopathy. a viral infection of the brain. Symptoms include memory loss, loss of strength, coma, and death.
pmpa: an experimental nucleotide analog, related to PMEA. PMPA can enter infected as well as uninfected cells.
pms: see premenstrual syndrome.
pneumococcus: the organism that causes pneumococcal pneumonia.
pneumocystis carinii pneumonia: a fungal inflamation of the lungs, commonly abbreviated PCP. PCP was once the leading cause of death of people with HIV Disease. Today it is still dangerous but is often treatable and preventable. PCP is considered an AIDS-defining condition in the United States.
pneumocystis carinii pneumonia (pcp): a life-threatening type of pneumonia believed to be caused by a protozoan. PCP is a common infection that can cause severe illness in immunocompromised people (especially those with CD4 counts less than 200 cells/mm3); it remains a leading cause of death in people with AIDS. Symptoms include dry cough, fever, chest tightness and shortness of breath. Pneumocystis carinii can also infect other parts of the body. First-line treatment and primary prophylaxis is TMP-SMX (Bactrim, Septra); other treatments and prophylaxes include dapsone, pentamidine and atovaquone.
pneumonia: a group of diseases that show up as an inflamation of the lungs. Recurrent pneumonia (pneumonia recurring within 1 year) is considered an AIDS-defining condition in the United States.
pneumonitis: an inflamation of the lungs. The disease pneumonia is on type of pneumonitis.
pneumovax vaccine: a vaccine developed to prevent pneumonia caused by common pneumococcal strains.
pns: see peripheral nervous system.
po: given by mouth (from the Latin per os).
pol: the HIV gene that encodes the replicative enzymes (protease, integrase, reverse transcriptase); also the protein produced by that gene.
poly- (prefix): many.
polycythemia: abnormally high level of red blood cells in the circulating blood.
polymerase: an enzyme that cleaves polymers, chemical compounds formed by the linkage of molecular pieces.
polymerase chain reaction (pcr) assay: a highly sensitive test that can detect small amounts of DNA or RNA in blood or tissue samples using an amplification technique that multiplies the existing DNA/RNA so that it can more easily be detected.
polymerase chain reaction assay (pcr): a sensitive lab test to determine a patient's viral load. It works by repeatedly copying genetic material using heat cycling and enzymes. A viral load test is used to see how well a drug regimin is working. The lower the viral load the better.
polymicrobial: including or caused by more than one microorganism.
polymorphonuclear leukocyte (pmnl): a type of white blood cell (e.g., neutrophil) containing more than one nucleus. PMNL are phagocytes (scavenger cells) important in immune defense, particularly against cell-free organisms such as fungi.
polyneuropathy: a type of peripheral neuropathy that involves damage to multiple nerves of the peripheral nervous system. Demyelinating polyneuropathy (which involves the destruction of the myelin sheath surrounding the neurons) and sensory axonal polyneuropathy are common in people with HIV disease. Symptoms may include weakness and painful tingling or burning sensations. See also peripheral neuropathy.
polyp: any mass of tissue that bulges or projects outward or upward from the normal surface level. A polyp may be a precursor to cancer.
polyprotein: a long thread of proteins produced during viral replication. The polyprotein is broken down by the protease enzyme into smaller components, which are then assembled into new virus particles.
polyradiculopathy: a type of peripheral neuropathy characterized by the inflammation of the nerve roots.
polysaccharide: a carbohydrate compound made up of 2 or more sugar molecules; a component of the capsules of fungi.
poppers: see nitrite inhalant.
positron emission tomography (pet) scan: a method of imaging the brain by recording activity, as measured by cerebral blood flow, in different parts.
post hoc: after the fact.
post mortem: after death. A post mortem examination is an autopsy.
post-herpetic neuralgia (phn): the often severe pain along a nerve pathway that sometimes follows the healing of herpes zoster (shingles) lesions.
post-marketing study: see Phase IV trial.
postnatal: the period following birth.
postpartum: the period following childbirth.
potassium: a mineral necessary for the maintenance of homoestatis by the body.
potentiation: an increase in activity or effectiveness; an interaction between drugs that results in a synergistic effect.
power: a statistical term used to describe the ability of an experiment or trial to find a particular result. Generally the power of a study increases as more subjects are included or as the trial continues for a longer period of time.
poxvirus: one of a large family of viruses (e.g., smallpox) that typically cause skin eruptions.
ppd: a test for tuberculosis. A positive result means you have been exposed and should be treated, but it does not mean you have the disease.
ppd test (mantoux test): a test that uses an injection of a purified protein derivative of tuberculin to test for prior exposure to Mycobacterium tuberculosis. A positive reaction is indicated by induration (redness and swelling) at the injection site. See also tine test.
preclinical testing: testing of an experimental drug in the laboratory or in animals prior to testing in humans.
prednisone: a corticosteroid drug with immunosuppressive effects that is used to decrease inflammation. Side effect may include mood changes, nausea and high blood pressure.
pre-existing condition: a medical problem that existed before or a specific date.
premalignant: refers to cells that display abnormal growth and development and may be an early stage in the development of cancer. See also dysplasia.
premature rupture of membranes: a breaking open of the amniotic sac surrounding the fetus that occurs more than 4 hours before the onset of labor.
premenstrual syndrome (pms): a set of symptoms occurring before or during the menstrual period, characterized by cramps, fatigue, bloating and mood changes.
prenatal: the period preceding birth, during which the fetus develops in the uterus.
presumptive diagnosis/treatment: treatment based on an assumed diagnosis, prior to receiving confirmatory laboratory test results.
prevalence (prevalence rate): the number of individuals with a condition in a specific population. The prevalence rate is determined by dividing the number of people with the condition by the total population.
preventive vaccine (prophylactic vaccine): a vaccine that is intended to prevent a disease from occurring by priming the immune system to respond to a pathogenic organism. Contrast with therapeutic vaccine.
primary care: basic medical care; the first line of medical management of a condition.
primary central nervous system lymphoma: a malignant proliferation of B-cells in the central nervous system associated with the Epstein-Barr virus. Symptoms include partial paralysis, aphasia, lethargy, confusion, memory loss and seizures.
primary hiv infection: the initial stage of infection with HIV, prior to the development of antibodies. Primary HIV infection may be accompanied by acute retroviral syndrome, characterized by flu-like symptoms including fever, malaise, enlarged lymph glands, sore throat, skin rash, and muscle and/or joint aches.
primary infection: the initial introduction of an infectious organism into the body.
primary prophylaxis: a treatment intended to prevent the first occurrence of an infection or disease. Contrast with secondary prophylaxis.
principal neutralizing determinant: the part of an antigen that most reliably induces a protective immune response. The principal neutralizing determinant of HIV is the V3 loop of the envelope glycoprotein gp120.
principle investigator: the chief researcher in a clinical trial.
prn: administered as needed (from the Latin pro re nata).
probenicid: a drug that promotes metabolism by the liver and kidneys, and which may be given with other drugs to lessen liver and/or kidney toxicity.
proctitis: inflammation of the mucous membranes of the rectum.
proctoscopy: examination of the rectum and lower end of the colon with a lighted instrument. See also sigmoidoscopy.
prodrome: a set of symptoms or signs (e.g., itching, tingling, pain) that indicate the onset of a disease (e.g., a herpes simplex outbreak).
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.
progesterone: a female steroid hormone with anti-estrogen effects. Progesterone prepares the uterus for the development of the fertilized ovum and maintains the uterus throughout pregnancy. Synthetic progesterone is used as a contraceptive.
progestin: a hormone produced by the corpus luteum, placenta or adrenal cortex (or synthetically manufactured) that has progesterone-like effects. Synthetic progestin is used as a contraceptive.
prognosis (adjective prognostic): a forecast of the probable course and/or outcome of a disease.
programmed cell death: see apoptosis.
progression: advancement of a disease.
progressive disease: a disease that continually increases in severity.
progressive multifocal leukoencephalopathy: a viral infection of the brain -- commonly abbreviated as PML. Symptoms include memory loss, loss of strength, coma, and death. This is considered an AIDS-defining condition in the United States.
progressive multifocal leukoencephalopathy (pml): a rapidly progressing, often fatal brain disease believed to be caused by the Jacob-Creutzfeldt (JC) papovavirus. PML infects oligodendrocytes (support cells in the brain) and leads to dysfunctional nerve signal transmission. Symptoms include headaches, changes in mental status, speech and vision difficulties, limb weakness, seizures, partial paralysis and loss of coordination.
proinflammatory cytokine: a chemical messenger (e.g., IL-1, IL-6, tumor necrosis factor) produced by the body that promotes an inflammatory immune response.
prokinetic antiemetic: a drug that relieves nausea by promoting gastrointestinal motility, or speeds up the digestive and excretory processes.
prolactin: a pituitary hormone that stimulates the secretion of breast milk.
proleukin: see interleukin 2.
proliferation: rapid or uncontrolled reproduction or replication.
prom: see premature rupture of membranes.
prophylactic vaccine: see preventive vaccine.
prophylaxis: a defense or protection. Several drugs are available to patients with suppressed immune systems to prevent certain opportunistic infections. For example, Bactrim is a prophylaxis against PCP. Using a condom is a phophylaxis against most sexually transmitted diseases.
prophylaxis (px): a treatment that helps to prevent a disease or condition before it occurs (primary prophylaxis) or recurs (secondary prophylaxis).
prospective study: a study that looks forward in time. Patients are selected and their progression is followed. A prospective cohort study follows a specific group of people over a period of time. Contrast with retrospective study.
prostaglandin: a locally-acting chemical messenger that is produced by many types of cells. Prostaglandins have a wide variety of effects including vasodilation and smooth muscle regulation; prostaglandins have a role in allergic reactions, uterine contraction, inflammation and pain signaling.
prostate gland: a large gland in males located at the base of the urethra that manufactures the liquid portion of semen.
protease: an enzyme that breaks down proteins and is used in cell replication. There are many kinds of protease, most of which are beneficial. One enzyme is specific to the HIV replication process.
protease (proteinase): an enzyme that cleaves proteins. HIV protease cleaves the large precursor proteins produced from viral RNA into the component parts (e.g., enzymes and structural proteins) that are then assembled into new viral particles. Protease is essential for the production of infectious new virions.
protease inhibitor: a class of anti-HIV drug that prevents creation of an HIV-specific protease.
protein: a complex compound (nitrogenous organic) containing amino acids, used in growth and repair of tissue.
proteinase: see protease.
proteinuria: the abnormal presence of protein in the urine.
prothrombin time (pt): a test that measures blood coagulation ability. Prothrombin is a protein produced by the liver that facilitates blood clotting. See also coagulation factor.
protocol: the official prospectus (plan) of a clinical trial. The protocol explains the purpose of the experimental treatment, and how the results will be tested and evaluated. It also contains information about drug dosing, duration, and inclusion/exclusion criteria.
protozoan: an acellular or 1-celled microorganism, several of which can cause disease in humans.
provirus: a viral state in which viral DNA has been inserted into the chromosome of the host cell.
proximal: closest to the center or to a central point of reference.
pruritus (adjective pruritic): a condition characterized by itching.
pseudomembranous candidiasis: see oral candidiasis.
pseudomeningitis: see meningismus.
pseudomonas: a group of aerobic rod-shaped bacteria, some of which (e.g., P. aeruginosa, P. flourescens) can cause opportunistic infections in human.
psoriasis: a common chronic skin condition characterized by reddish scaly patches, primarily on the scalp, elbows, knees and trunk. Outbreaks are more common and may be more severe in HIV-infected individuals. Psoriatic arthritis is a form of arthritis accompanied by psoriasis.
psychomotor: relating to mental functioning and control of muscular movement.
psychoneuroimmunology (pni): the study of how psychological processes, mental state, and neurological and hormonal factors affect the functioning of the immune system.
psychopharmacology: the use of drugs that affect the psyche or personality.
psychosis: a major mental disorder (e.g., schizophrenia, bipolar disorder) that affects the ability to function normally on a daily basis.
psychosocial: refers to factors that affect the psychological or social realm. Psychosocial factors (e.g., socioeconomic status, education, family situation) may make an important contribution to disease risk and progression, and are an essential aspect of a person's well-being.
psychotropic: an agent (e.g., thorazine) that affects psychic or mental functioning or behavior.
public health service (phs): the U.S. federal agency, part of the Department of Health and Human Services, that oversees the health of the public, monitors epidemics, etc. The National Institutes of Health (NIH) and the Centers for Disease Control and Prevention (CDC) are part of the PHS.
puerperal sepsis (puerperal fever): an infection (e.g., with Streptococcus bacteria) acquired during childbirth. Puerperal fever is an outcome of puerperal sepsis characterized by fever, rapid heartbeat and inflammation of the uterus; the condition may be fatal.
pulmonary: relating to the lungs.
pulse oximetry: a method of measuring the amount of oxygen in the blood by means of a clip-like instrument that attaches to the finger.
punch biopsy: the removal of a small piece of tissue from the skin or mucous membrane for diagnostic analysis.
purine: one of the 2 types of nucleotide bases that make up DNA and RNA. The purine bases are adenine and guanine. See also pyrimidine.
purpura: a purplish discoloration due to bleeding underneath the skin.
purulent: characterized by the accumulation of pus.
pus: a thick, greenish-yellow fluid composed of dead white blood cells, killed microorganisms and other cellular debris.
pustule: a small skin elevation or blister containing pus.
p-value: a probability value that is reported in experiments such as clinical trials. The p-value indicates how likely it is that the result obtained by the experiment is due to chance alone. A p-value of less than .05 is considered statistically significant, that is, not likely to be due to chance alone.
pwa: abbreviation, Person with AIDS.
pwhiv: person or people with HIV infection.
px: medical abbreviation for preventive therapy or prophylaxis.
pyridoxine (vitamin b6): a form of vitamin B that helps prevent peripheral neuropathy side effects when used with certain drugs (e.g., isoniazid).
pyrimethamine (daraprim): a drug used to treat protozoan infections such as toxoplasmosis. Side effects include bone marrow suppression and allergic skin reactions.
pyrimidine: one of the 2 types of nucleotide base that make up DNA and RNA. The pyrimidine bases are cytosine, thymine and uracil. See also purine.