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|Glossary of Terms
This glossary is provided for the convenience of the users of this web site. It is not intended to be a substitute for medical advice or serve as official scientific definitions.
Adenine (A) - (= 6-aminopurine). One of the purine bases found in nucleic acids and nucleotides. In DNA, it always pairs with thymine (T).
Antibacterial - A substance that destroys bacteria, or suppresses their growth or reproduction.
Antibiotic - A chemical substance produced by a microorganism that has the capacity to kill or inhibit the growth of other microorganisms (e.g., penicillin, tetracycline, vancomycin, or methicillin).
Antibiotic resistance - The ability of a bacterium to resist or overcome the effects of an antibiotic.
Antifungal agent - A substance that has the capacity to kill or inhibit the growth of fungi.
Antiviral agent - A substance that has the capacity to stimulate cellular defenses against viruses. For example, an antiviral agent can reduce cell DNA synthesis thus making cells more resistant to viral genes, enhancing cellular immune responses, or suppressing viral replication.
Aspergillus sp. - A family of fungi found worldwide that can opportunistically cause a disease of the respiratory tract called aspergillosis. The severity of aspergillosis can range from mild allergy-like symptoms to life-threatening invasive infections.
Candida sp. - A family of yeast-like fungi that is commonly present in humans, but can sometimes cause pathogenic infections. The strain Candida albicans, for example, causes a disease called thrush and also systemic candidosis, affecting various organs such as the urinary tract, kidneys, heart, lungs and the nervous system.
Cidal - A property of a drug that means it acts by killing the target organism (e.g., bacteriocidal). See also Static.
Compound optimization - The process whereby a promising candidate drug molecule is systematically changed to improve its properties. Typical goals of the optimization process include improving a drug's effectiveness (activity and efficacy), its availability in the body (bioavailability), its clearance profile (pharmacodynamics), and reducing its toxicity.
Cryptococcus sp. - A genus of yeast-like fungi that reproduce by budding.
Cytosine (C) -A pyrimidine base found in DNA and RNA. In DNA, it always pairs with guanine (G).
DEXA (or DXA) - Dual Energy X-ray Absorptiometry - A tool for evaluating bone mineral density.
DNA - Deoxyribonucleic acid. This molecule carries and transfers the genetic information for all biological organisms.
Drug Development Stages - Potential drugs go through many stages before they can be marketed as products. Before being tested in humans, a drug candidate goes through discovery, optimization, and preclinical development. After these processes are complete, an application is made to the FDA (Food and Drug Administration) to begin human testing called an Investigational New Drug application, or IND. If the IND is approved, Phase I clinical trials assess a drug's tolerability at various dose levels in a small number of healthy volunteers or patients. Then Phase II studies are conducted to establish effectiveness and safety; usually several doses are studied in a larger number of patients. Phase III studies are then performed for a longer duration and in a larger number of patients at the dose determined from Phase II studies to accrue long-term efficacy and safety data. Finally, all of the relevant data and analysis are compiled into a New Drug Application (NDA) and submitted to the FDA.
Efficacy - The ability of a drug to control or cure an illness.
Gene - A section of DNA that encodes a specific functional product (protein). Genes are the fundamental physical and functional units of heredity.
Gene expression - The process by which a gene's coded information is converted into the structures present and operating in the cell. Expressed genes include those that are transcribed into mRNA and then translated into protein, and those that are transcribed into RNA but not translated into protein (e.g., transfer and ribosomal RNAs).
Genome - The complete set of genetic information of an organism including DNA and RNA.
Giardia sp. - Flagellated protozoa that cause gastroenteritis in man (Giardia lamblia).
Guanine (G) - (= 2-amino 6-hydroxy purine). A constituent purine base found in nucleic acids. In DNA, it always pairs with cytosine (C).
Hepatitis - Inflammation of the liver. Hepatitis can be caused by viruses, bacteria, alcohol, toxic chemicals, and certain drugs. Symptoms include jaundice (yellowish skin caused by the buildup of bile pigments in the body), fever, appetite loss and gastrointestinal upset.
HxV - Viruses that cause hepatitis are lettered A through G.
HBV - A DNA virus in the family Hepadnaviridae. Hepatitis B has a long incubation period (around three months) and can cause severe liver damage and even death. It is typically spread by blood or body fluid contact, such as through hypodermic needles or sexual intercourse. A type of liver cancer called hepatoma can follow HBV infection.
HCV - Hepatitis C virus is also referred to as nonA-nonB hepatitis and is the most common form of blood transfusion-acquired hepatitis.
HEV - Genelabs scientists discovered the Hepatitis E virus. The Hepatitis E virus causes a form of viral hepatitis that cannot be determined to be hepatitis A, B, C or D through testing.
HGV - Genelabs scientists discovered the Hepatitis G virus. Hepatitis G virus has not been associated with any human disease. (HGV is sometimes referred to as GBV-C).
HIV - Human Immunodeficiency Virus, the virus that causes Acquired Immuno-Deficiency Syndrome (AIDS).
Immunocompromised - A condition in which the immune system is weakened as the result of disease, drugs or malnutrition.
IND - Investigational New Drug application, a proposal to the US Food and Drug Administration (FDA) to begin testing of a candidate drug in humans in order to assess its safety and effectiveness (efficacy).
Infectious disease - A disease that can be transmitted from person to person or from organism to organism, and is caused by a microbial agent (e.g., common cold).
In vitro - A Latin term meaning "in glass." Initial studies for drug effectiveness are first conducted in vitro or in a "test tube" environment.
In vivo - A Latin term meaning "in body." After a candidate drug passes in vitro testing, it is then tested in living bodies. In vivo testing typically starts with mice or rats, and then progresses up to human testing. A candidate drug must have favorable properties in each successive species before the next species is tested.
Lupus - A Latin word that literally means "wolf." Lupus is also used to refer to a disease called Systemic Lupus Erythematosus (SLE), a serious, chronic autoimmune disease that often induces a facial rash that causes its sufferers to have a wolf-like appearance. Individuals with lupus will produce antibodies to their own body tissues. The resultant inflammation can cause damage in many organs of the body including kidney, joints, blood vessels, heart and lungs.
MRSA - Methicillin-Resistant Staphylococcus aureus. MRSA is a strain of Staphylococcus aureus that has become resistant to the antibiotic methicillin.
NDA - New Drug Application, a complete application (typically thousands of pages long) to the FDA (Food and Drug Administration) to begin marketing of a drug product in the US.
Nucleotides - The basic building blocks of nucleic acids (DNA and RNA). Nucleotides are made up of a nitrogen-containing purine or pyrimidine base linked to a sugar (ribose or deoxyribose) and a phosphate group.
P value - Statistical data, such as data from human tests of a candidate drug, are often accompanied by a P value, which is the mathematical probability that the data are the result of random chance. Data with a low P value (less than or equal to 0.05) are said to be "statistically significant." For example, a P value of 0.05 means that there is a 1 in 20 chance that the data is the result of random chance.
Pathogenic - Disease-causing.
Pharmacokinetics - Studies that determine the action of a drug in the body over a period of time, including the processes of absorption, distribution, localization in tissues and excretion.
Pharmacology - The medical science that deals with the discovery, composition, identification, biological/physiological effects, uses and manufacture of drugs.
Promoter region - A location on DNA to which RNA polymerase will bind and initiate transcription of the associated gene(s).
Protein - A large organized molecule composed of one or more amino acids chains. The order of the amino acids is determined by the base sequence of nucleotides (base pairs) in the gene coding for the protein. Proteins are required for the structure, function, and regulation of cells, tissues, and organs. Hormones, enzymes and antibodies are proteins.
RNA - Ribonucleic Acid. A molecule similar in structure to DNA that is used in the process of building proteins from the instructions contained in DNA. Also, some viruses use RNA instead of DNA as their genetic material.
SLAM - Systemic Lupus Activity Measure. A method of measuring the disease activity of lupus.
SLEDAI - Systemic Lupus Erythematosus Activity Index. A method of measuring the disease activity of lupus.
Static - In biology, a property of a drug that means it acts by inhibiting the growth or spread of an organism such as bacteria (e.g., bacteriostatic). See also Cidal.
Steroid - A lipid found in plants and animals that share a common underlying chemical structure. They are usually hormones or constituents of cell membranes. Common steroids include estrogen, testosterone, cortisone, Vitamin D, and cholesterol.
Structure-activity relationship (SAR) - The analysis of the relationship between the chemical structure of a compound and its biological or pharmacological activity. Molecular structure and biological activity are correlated by observing the results of systematic structural modification on defined biological endpoints.
Thymine (T) - (= 2, 6-di-hydroxy, 5-methylpyrimidine; 5-methyluracil). One of the pyrimidine bases found in DNA. In DNA, it always pairs with adenine (A). Uracil is used instead of thymine in RNA.
Toxicity - Quality of being poisonous. Examples of toxicity include the degree of toxicity of a virulent microbe, a compound, or drug.
Toxicity testing - Performing controlled testing in the laboratory to determine the toxicity of a compound or drug to an organism at various concentrations. Acute toxicity testing is used to establish the concentration of drug required to kill a predetermined proportion of test organisms within a relatively short period of time, typically 4 days or less. Chronic toxicity testing is used to establish the effects of a sub-lethal concentration of drug applied throughout all or part of the organism's life cycle.
Transcription - The process of synthesizing RNA from a DNA template. Specific enzymes called RNA polymerases transcribe the DNA.
Transcription factors - Specific proteins which allow DNA recognition by RNA polymerases in eukaryotes.
Transcriptional activation - The process by which the two DNA strands separate in order to allow replication. Short RNA sequences hold apart the DNA strands to allow a primosome to bind and synthesize primers for DNA synthesis.
Translation - The synthesis of a protein directed by mRNA (messenger RNA). Translation occurs at the ribosome where mRNA is used to specify the sequence of amino acids in the polypeptide chain.
Trichomonas sp. - Water-borne flagellated protozoa which can cause urinary tract infections and vaginitis.
VRE - Vancomycin-Resistant Enterococcus - Enterococci bacteria are normally found in the intestinal tract. They can sometimes become pathogenic and develop resistance to vancomycin. (Vancomycin is a last-resort antibiotic that is administered for infections that are resistant to penicillin and other antibiotics.)