Glossary L

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laparoscopy: a technique that allows the physician to observe internal organs directly through a piece of  optical equipment inserted directly into the body through a small surgical incision

laparotomy: an operation in which the abdomen is opened to look for the cause of an undiagnosed illness

latent: 1) insignificant or irrelevant; for example, latent prostate cancer (also known as incidental prostate cancer) is a form of prostate cancer which is of no clinical significance to the patient in whom it is discovered; 2) pathology. in a dormant or hidden stage

LDL cholesterol: low density lipoprotein cholesterol; a lipoprotein of blood plasma that is composed of a moderate proportion of protein with little triglyceride and a high proportion of cholesterol and that is associated with increased probability of developing atherosclerosis

lesions: a localized pathological change in a bodily organ or tissue

leuprolide acetate: a LHRH analog; one trade name is Lupron®

levator: a muscle that raises a structure in the body such as the muscles that support the pelvic organs

Leydig cells: cell population within the testicles that produces testosterone; the other main cell population are the Sertoli cells that make sperm

LH: luteinizing hormone; a pituitary hormone that stimulates the Leydig cells of the testicles to make the male hormone testosterone

LHRH: luteinizing hormone-releasing hormone (also known as GnRH or gonadotrophin releasing hormone; hormone from the hypothalamus that interacts with the LHRH receptor in the pituitary to release LH)

see luteinizing hormone releasing hormone

LHRH analogs (or agonists): Synthetic compounds that are chemically similar to Luteinizing Hormone Releasing Hormone (LHRH), but are sufficiently different that they suppress testicular production of testosterone by binding to the LHRH receptor in the pituitary gland and either have no biological activity and therefore competitively inhibit the action of LHRH, or has LHRH activity that exhausts the production of LH by the pituitary; used in the hormonal treatment of advanced prostate cancer and in the adjuvant  and neoadjuvant hormonal treatment of earlier stages of  prostate cancer; LHRH agonist (mimics natural LHRH but then shuts down LH production after continuous exposure)

LHRH antagonist: an agent that blocks the LHRH receptor by pure antagonism without the initial release of LH seen with LHRH agonists; abarelix (Plenaxis®) is an example

libido: interest in sexual activity; the psychic and emotional energy associated with instinctual biological drives

ligand: An ion, a molecule, a molecular group, a substance or messenger that binds to another chemical entity at a receptor to form a larger complex which is then activated

ligate, ligation: join together

linear accelerator: A type of high energy X-ray machine that generates radiation fields for external beam radiation therapy. A linear accelerator is typically mounted with a collimator and/or a multileaf collimator in a gantry that revolves vertically around a treatment couch

lipid: fat stored by the body; the two most commonly measured kinds of lipids are triglycerides and cholesterol.

lipomatosis: condition characterized by abnormal localized, or tumor-like, accumulations of fat in the tissues

LNCaP: a line of human prostate cancer cells used in laboratory studies; this cell line is hormonally dependent; See androgen dependent.

lobe: one of the two sides of an organ that clearly has two sides (e.g., the prostate or the brain)

local therapy: treatment that is directed at the prostate and closely surrounding tissue

localized: restricted to a well defined area

LSESr (LIPO-sterolic extract of Serenoa repens): the lipid extracted portion of saw palmetto

lumbar: portion of body between chest and pelvis, often referring to the lower back or spine

lumen: a cavity or channel into any organ or structure of the body

Lupron®: the USA trade or brand name of a leuprolide acetate, a LHRH agonist

luteinizing hormone releasing hormone (LHRH): a hormone responsible for stimulating the production of testosterone in the body by interacting with the LHRH receptor to release LH which in turn stimulates cells in the testicles (Leydig cells) to make testosterone;  luteinizing hormone-releasing hormone is also known as GnRH or gonadotrophin-releasing hormone

LUTS: lower urinary tract symptoms; include symptoms of hesitancy in initiating urination, slow urination, dribbling after urination, getting up at night to urinate (nocturia) and frequency of urination; these symptoms are part of the AUA symptom score index

LY294002: a lipid-modifying enzyme that inhibits PI3 kinase

lycopene: A carotenoid responsible for the red color of the tomato, watermelon and pink grapefruit. Recent findings indicate that lycopene may be an important part of the human organism’s natural defense mechanism that protects from harmful oxidizing agents

lymph (also lymphatic fluid): the clear fluid in which all of the cells in the body are constantly bathed; carries cells that help fight infection

lymph nodes: the small glands which occur throughout the body and which filter the clear fluid known as lymph or lymphatic fluid; lymph nodes filter out bacteria and other toxins, as well as cancer cells

lymphadenectomy: also known as a pelvic lymph node dissection, this procedure involves the removal and microscopic examination of selected lymph nodes, a common site of metastatic disease with prostate cancer; this procedure can be performed during  surgery prior to the removal of the prostate gland, or by means of a small incision a "laparoscopic lymphadenectomy" may be performed, a simple operation requiring only an overnight stay in the hospital

lymphadenopathy: disorder of the lymph nodes or vessels

lymphatic system: the tissue and organs that produce , store and carry cells that fight infection; includes bone  marrow, spleen, thymus, lymph nodes, and channels that carry lymph fluid

lymphocele: cystic mass containing lymph from diseased lymphatic channels or following surgical trauma or other injury

lymphocyte: white blood cell

lymphography: radiologic depiction of lymphatic vessels and lymph nodes after use of a contrast material

lytic: of, relating to, or causing a specified kind of decomposition through rupture of cell membranes and loss of cytoplasm