A bullet-shaped core made of another protein that surrounds the viral RNA within the envelope of HIV. The p24 antigen test looks for the presence of this protein in a patient's blood. A positive result for the p24 antigen suggests active HIV replication. p24 found in the peripheral blood is also thought to correlate with the amount of virus in the peripheral blood.

Palliative care is an approach to life-threatening chronic illnesses, especially at the end of life. Palliative care combines active and compassionate therapies to comfort and support patients and their families who are living with life-ending illness. Palliative care strives to meet physical needs through pain relief and maintaining quality of life while emphasising the patient's and family's rights to participate in informed discussion and to make choices.

Abnormal sensations such as burning, tingling, or a "pins-and-needles" feeling. Paresthesia may constitute the first group of symptoms of peripheral neuropathy, or it may be a limited drug side effect that does not worsen with time. Circumoral paresthesia affects the area around the mouth.

Also referred to as acquired immunity. Passive immunity can be acquired from the transfer of antibodies from another person or from an animal, either naturally � as from mother to foetus � or by intentional inoculation. The latter is also called artificial passive immunity. Passive immunity is specific with respect to the particular antibodies transferred. Passive, cell-mediated immunity produced by the transfer of living lymphoid cells from an immune animal to a normal one is sometimes referred to as adoptive immunity.

Process in which individuals with advanced disease (who have low levels of HIV antibody production) are infused with plasma rich in HIV antibodies or an immunoglobulin concentrate (HIVIG) from such plasma. The plasma is obtained from asymptomatic HIV-positive individuals with high levels of HIV antibodies.

Polymerase Chain Reaction. The process of target amplification used in the AMPLICOR Microwell Plate Tests and COBAS AMPLICOR� Analyser Automated PCR Tests.

Transmission of a pathogen, such as HIV, from mother to baby before, during, or after the birth process. Ninety percent of children reported with AIDS acquired HIV infection from their HIV-infected mothers.

Condition characterised by sensory loss, pain, muscle weakness, and wasting of muscle in the hands or legs and feet. It may start with burning or tingling sensations or numbness in the toes and fingers. In severe cases, paralysis may result. Peripheral neuropathy may arise from an HIV-related condition or be the side effect of certain drugs, in particular some of the nucleoside analogues.

Chronic, diffuse, non-cancerous lymph node enlargement. Typically it has been found in persons with persistent bacterial, viral, or fungal infections. PGL in HIV infection is a condition in which lymph nodes are chronically swollen in at least two areas of the body for 3 months or more with no obvious cause other than the HIV infection.

The outward appearance or behaviour of an organism (e.g. virus or human). The phenotype depends partly on the organism�s genotype and partly on the environment (e.g. nutrients, temperature). Drug resistance in HIV is the phenotypic expression of resistance genes.

A procedure whereby a sample DNA of a patient's HIV is tested against various antiretroviral drugs to see if the virus is susceptible or resistant to these drug(s).

An infection of the lungs caused by Pneumocystis carinii, which is thought to be a protozoa, but may be more closely related to a fungus. P. carinii grows rapidly in the lungs of persons with AIDS and is a frequent AIDS-related cause of death. P. carinii infection sometimes may occur elsewhere in the body (skin, eye, spleen, liver, or heart). The standard treatment for persons with PCP is either a combination of trimethoprim and sulfamethoxazole (TMP/SMX, also called Bactrim or Septra), dapsone, or pentamidine.

A gene found in HIV and other retroviruses. It encodes reverse transcriptase and other essential enzymes essential to retroviral replication inside the host cell. Several pol mutations are known to be associated with resistance to different antiviral drugs.

An enzyme that is capable of synthesizing new strands of DNA from a single stranded template and free deoxynucleotides under appropriate reaction conditions. During PCR, Roche systems use Taq DNA Polymerase to make DNA amplicon using the DNA strand as a template. rTth DNA Polymerase is used to perform reverse transcription (synthesizing cDNA from RNA) and which then, through PCR, produces DNA amplicon.

A method that increases the sensitivity of DNA testing (e.g. to detect HIV) by making multiple copies of the DNA sequence in question.

A small synthetic segment of DNA used to initiate or "prime" the new DNA synthesis. In PCR, primers are small segments of DNA of a defined length and sequence that are used to initiate DNA synthesis by DNA Polymerase (Taq or rTth).

A small piece of DNA that is used to isolate or detect complementary target in the reaction mixture.

A rapidly debilitating opportunistic infection caused by the JC virus that infects brain tissue and causes damage to the brain and the spinal cord. Symptoms vary from patient to patient, but include loss of muscle control, paralysis, blindness, problems with speech, and an altered mental state. PML can lead to coma and death.

An enzyme that breaks down proteins into their component peptides. HIV's protease enzyme breaks apart long strands of viral protein into the separate proteins making up the viral core. The enzyme acts as new virus particles are budding off a cell membrane.

Antiviral drugs that act by inhibiting the virus protease enzyme, thereby preventing viral replication. Specifically, these drugs block the protease enzyme from breaking apart long strands of viral proteins to make the smaller, active HIV proteins that comprise the virion. If the larger HIV proteins are not broken apart, they cannot assemble themselves into new functional HIV particles.

A molecule consisting of a chain of amino acids. A major source of the building materials for tissues (e.g. muscle, blood), enzymes, receptors and many other body components.

Large group of one-celled (unicellular) animals, including amoebas. Some protozoa cause parasitic diseases in persons with AIDS, notably toxoplasmosis and cryptosporidiosis. See Pneumocystis carinii Pneumonia.

Viral genetic material, in the form of DNA that has been integrated into the host genome. HIV, when it is dormant in human cells, is in a proviral form.

Material used in the tuberculin skin test (TST); the most common test for exposure to Mycobacterium tuberculosis, the bacterium that causes TB. PPD is sometimes used synonymously with TST. In the PPD test, a small amount of protein from TB is injected under the skin. If patients have been previously infected, they will mount a delayed-type hypersensitivity reaction, characterised by a hard red bump called an induration.

The name that classifies the bases with a two-ringed structure, Adenine and Guanine. Purine bases will only bond with pyrimidine bases.

The name that classifies the bases with one-ringed structures: Thymine, Cytosine and Uracil. Pyrimidine bases will only bond with purine bases.