Mesothelioma Glossary

A

ASBESTOS CONTAINING MATERIALS (ACM): Materials such as ceiling tiles, floor tiles, gaskets, packing, joint compound, heat insulation and brake linings produced before 1990 commonly contained asbestos.

ADENOCARCINOMA: Type of cancer that begins in the cells that line certain internal organs such as the lungs.

ADJUVENT THERAPY: A supplemental treatment to the main medical procedure. This treatment usually comes in the form of radiation therapy or chemotherapy, and is employed after surgery.

AFFIDAVIT: A written statement whereby the signer swears to its truth before a notary or other judicial officer. A witness affidavit may be accepted in place of testimony in court.

AJCC STAGING SYSTEM: American Joint Committee on Cancer staging system (also called the TNM system), which describes the extent of a cancer’s spread in Roman numerals from 0-IV.

ALIMTA: A chemotherapy drug developed by Eli Lilly specifically for mesothelioma patients.

ALVEOLAR EPITHELIAL CELLS: Cells that line the lung air sacs.

ALVEOLAR SACS: Small air chambers in the lung.

ALVEOLI: Tiny, thin walled air sacs in the lungs where oxygen and carbon dioxide exchange places. Asbestos fibers in the lungs cause scar tissue to form on the walls of the alveoli, decreasing oxygen intake.

AMPHIBOLE: A type of mineral, distinguished by a chain-like crystal structure and chemical composition. Asbestos amphiboles include actinolite, amosite, anthophillite, crocidolite, and tremolite.

ANEMIA: A condition in which the number of red blood cells is below normal.

ANXIETY: Anxiety is a state of apprehension or fear, either real or imagined, resulting from anticipation of a threatening event or situation. Many victims of mesothelioma and their loved ones are faced with stress and anxiety.

APPEAL: A request to a higher court to reverse the decision of a lower court.

ARRHYTHMIA: An arrhythmia is any deviation from or disturbance of the normal heart rhythm.

ASBESTIFORM: A mineral that looks like asbestos.

ASBESTOS: is the commercial name given to a naturally occurring fibrous silicate mineral commonly used in construction materials and other products because of its high heat resistance, strength and durability. Over time, exposure to asbestos may lead to asbestosis, mesothelioma, lung cancer and other cancers.

ASBESTOSIS: Scarring of the lungs caused by inhaled asbestos fibers. Asbestosis is irreversible.

ASBESTOS PLEURAL DISEASE: A disease characterized specifically by scarring of the membranes lining the lungs and chest cavity.

ASCITES: Abnormal build-up of fluid in the abdomen that may cause swelling. In late-stage cancer, tumor cells may be found in the fluid in the abdomen. Ascites is a common manifestation of peritoneal mesothelioma and can occur as a manifestation of recurrent mesothelioma after surgery for the disease in the chest.

ASPIRATION: The medical process of removing a small sample of tissue for testing with a needle-like suction device.

ATELECTASIS: Incomplete expansion of a portion of the lung or the whole lung.

AUTOPSY: A surgical procedure after death which involves the examination of body tissues, often to determine cause of death.

B

BACKGROUND LEVEL: The average or expected amount of a substance in a specific environment.

BILATERAL: Disease in both lungs.

BIOMARKERS: A protein or compound easily detectable in the body that indicates an exposure has occurred.

BIOPSY: The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration. Pleural biopsies are used to make the diagnosis of mesothelioma.

BIPHASIC: A mesothelioma which has both epithelial and sarcomatoid elements. Also called a mixed mesothelioma.

B-READER: A person certified by NIOSH as qualified to interpret chest x-rays especially for dust disease, including asbestos disease.

BRONCHI: The two main air passages leading from the windpipe (trachea). They allow air to move in and out of the lungs.

BRONCHIOLE: One of the smaller subdivisions of the bronchi.

BRONCHOGENIC CARCINOMA/CANCER: A type of lung cancer.

BRONCHOPLEURAL FISTULA: A complication after extrapleural pneumonectomy in which there is a leakage of air from the closed bronchial tube.

BRONCHOSCOPY: A thin, lighted tube (bronchoscope) inserted through the nose or mouth to examine the breathing passages at the entrance to your lungs.

BUTCHART STAGING SYSTEM: The staging system most often used for mesothelioma. It is divided into stages I-IV with the levels determined by the tissue involved.

C

CACHEXIA: Loss of body weight and muscle mass, and weakness that may occur in patients with cancer, AIDS, or other chronic disease. Cachexia is a common manifestation of late stage mesothelioma.

CALCIFICATION: Process in which tissue becomes hardened as a result of calcium deposits.

CANCER: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).

CANCER CENTER: A hospital that specializes only in the care of patients with cancer. An NCI designated cancer center is specifically recognized and partially funded by the National Cancer Institute.

CARCINOGENIC: Substances that produce cancer or cancer growth.

CARDIOLOGIST: A specialist in the treatment of conditions related to the heart who would perform the appropriate tests to see if a patient is functionally able to tolerate surgery for mesothelioma.

CATHETER: A tube which could be used to drain urine from the bladder; an intravenous catheter is used to give fluids in the vein.

CHEMOTHERAPY: Drug treatment to destroy cancer cells.

CHEST X-RAY: A chest x-ray is a radiology test that involves exposing the chest briefly to radiation to produce an image of the chest and the internal organs of the chest. Chest x-rays can be used to define abnormalities of the lungs such as excessive fluid, pneumonia, bronchitis, asthma, cysts, and cancers.

CHRONIC: Occurring over a long time.

CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD): A progressive lung disease process characterized by difficulty breathing, wheezing, and a chronic cough. Complications include bronchitis, pneumonia and lung cancer.

CHRYSOTILE: Type of asbestos with a white curly fiber, chrysotile accounts for 90% of asbestos in products and is a member of the serpentine group. It is a magnesium silicate.

CISPLATIN: Platinum-containing chemotherapy agent that works by binding to DNA of tumor cells.

CLINICAL TRAILS: Research studies that test how new medical treatments and other interventions work in people. Tests may be preventative, diagnostic or therapeutic.

COMPLAINT: The document filed with the court stating the facts of your case and your legal claims against the asbestos companies.

COMPLEMENTARY AND ALTERNATIVE MEDICINE (CAM): Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices generally are not considered standard medical approaches. CAM may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation.

COMPLETE RESPONSE: The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called a complete remission.

CONTAMINANT: A substance that is present in a certain amount of soil, water, air, food, blood, hair, urine, breath, or any other media.

CROCIDOLITE: A member of the amphibole group of asbestos, crocidolite takes the form of blue, straight fibers. It is sodium iron magnesium silicate.

CRYOSURGERY: The use of an extremely cold probing instrument to destroy unwanted abnormal tissues.

CT SCAN: A type of x-ray that takes cross-sections of the body (like slices). Much more precise than typical x-rays.

CURATIVE TREATMENT: Treatment aimed at producing a cure. Compare with palliative treatment.

CYTOLOGY: The branch of biological science that deals with the structure and function of cells. In asbestos cases, it often refers to the testing of liquid removed from the outside of the lung.

D

DECORTATION: Removal of the external layer of an organ.

DEFENDANT: The asbestos companies that you are suing for damages.

DERMAL: Referring to the skin. For example, dermal absorption means passing through the skin.

DIAGNOSIS: The nature of a disease; the identification of an illness.

DIAPHRAGM: Muscular, membranous partition that separates the abdominal and thoracic cavities.

DIFFERENTIAL DIAGNOSIS: The determination of which two or more diseases with similar symptoms is the one from which a patient is suffering based on an analysis of the clinical data.

DIFFUSE: Not limited or localized; widely distributed.

DISEASE: Illness or sickness often characterized by typical problems (symptoms) and physical findings (signs).

DOSE: The amount of a substance to which a person is exposed over some time period. Dose is a measurement of exposure. In general, the greater the dose, the greater the likelihood of an effect. An “exposure dose” is how much of a substance is encountered in the environment. An “absorbed dose” is the amount of a substance that actually got into the body through the eyes, skin, stomach, intestines, or lungs.

DOSE-RESPONSE RELATIONSHIP: The relationship between the amount of exposure (dose) and the resulting changes in body function or health (response).

DYSPNEA: Difficult, painful breathing or shortness of breath. One of the early symptoms of mesothelioma in the pleura due to the accumulation of fluid in the chest.

E

ECHOCARDIOGRAM: A test that uses sound waves to create a moving picture of the heart. The picture is much more detailed than an x-ray image and involves no radiation exposure.

ENDOSCOPE: An illuminated optic instrument that is inserted through an incision.

EPA: The US government agency founded to “protect human health and to safeguard the natural environment–air, water and land–upon which life depends.” The Environmental Protection Agency is known as the EPA.

EPIDEMIOLOGICAL: Studies of how health-related conditions occur in specific populations.

EPIDEMIOLOGY: The study of the distribution and determinants of disease or health status in a population; the study of the occurrence and causes of health effects in humans.

EPIDURAL CATHETER: A catheter which allows injection of an anesthetic drug into the space between the wall of the spinal canal and the covering of the spinal cord. This is the most reliable means for short term pain relief after an operation for mesothelioma.

EPITHELIAL: Refers to the cells that line the internal and external surfaces of the body; the term used to describe the appearance of the cells under the microscope for the most common type of mesothelioma.

ESOPHAGITIS: Inflammation of the esophagus (the tube that carries food from the mouth to the stomach). This most frequently occurs in the area of chest radiation after an operation for mesothelioma.

EXPOSURE: Contact with a substance by swallowing, breathing, or touching the skin or eyes. Exposure may be short-term (acute exposure), of intermediate duration, or long-term (chronic exposure).

EXTERNAL-BEAM OPERATION: Radiation therapy that uses a machine to aim high-energy rays at the cancer. Also called external radiation. Most commonly used after removal of an entire lung for mesothelioma.

EXTRAPLEURAL PNEUMONECTOMY: Surgery to remove a diseased lung, part of the pericardium (membrane covering the heart), part of the diaphragm (muscle between the lungs and the abdomen), and part of the parietal pleura (membrane lining the chest). This type of surgery is used most often to treat malignant mesothelioma.

F

FIBROSIS: Formation of fibrous tissue (scarring) in an organ as part of a repair or reactive process.

FRIABLE: A material which when dry, may be crumbled, crushed, pulverized, or reduced to powder by normal hand pressure.

G

GENE: A segment of DNA that contains information on hereditary characteristics such as hair color, eye color, and height, as well as susceptibility to certain diseases.

GENE THERAPY: Treatment that alters a gene. In studies of gene therapy for cancer, researchers are trying to improve the body’s natural ability to fight the disease or to make the cancer cells more sensitive to other kinds of therapy by either adding a gene which was lost in the cancer or interfering with a gene which contributes to the growth of the cancer.

H

HAZARD: A source of potential harm from past, current, or future exposures.

HEMOPTYSIS: Coughing up blood.

HEMORRHAGE: In medicine, loss of blood from damaged blood vessels. A hemorrhage may be internal or external, and usually involves a lot of bleeding in a short time.

HILAR: Pertaining to the part of an organ where nerves and vessels enter and leave.

HISTOLOGY: The study of the structure and behavior of cells and body tissues, usually involving microscopic examination of tissue slices.

HOSPICE: A program that provides special care for people who are near the end of life, either at home, in freestanding facilities, or within hospitals.

I

IDIOPATHIC: Of a condition or disorder that occurs spontaneously for unknown reason.

INHALATION: The act of breathing. A hazardous substance can enter the body this way.

IMAGING TESTS: Takes pictures of the lungs and can detect problems such as a mass, an infection or air in the pleural space. Visual imaging tests include: chest x-rays and CT scans.

IMMUNOHISTOCHEMICAL: Refers to use of antibody-antigen stains to create reactions to locate markers specific to certain tissues or cells. This staining of human tissue is used to diagnose mesothelioma.

IMMUNOSTAINING: The use by pathologists of specific proteins with color producing labels attached to them to stain tissue sections in order to differentiate one tumor from another. It is particularly important to use a battery of immunostains in order to tell whether the biopsy is a mesothelioma or a lung cancer.

IMMUNOSUPPRESSANT: Substance that reduces the effectiveness of the body’s defense mechanisms.

IMMUNOTHERAPY: Administration of agents that induce a pro-inflammatory response.

INFORMED CONSENT: A process by which a person learns key facts about a clinical trial, including potential risks and benefits, before deciding whether or not to participate in a study. Informed consent continues throughout the trial.

INTERFERON: Substance that helps regulate immune responses.

INTERSTITIAL DISEASE: Fibrosis (scarring) in the lungs.

INTENSITY-MODULATED RADIATION THERAPY (IMRT): A type of 3-dimensional radiation therapy that uses computer-generated images to show the size and shape of the tumor. Thin beams of radiation of different intensities are aimed at the tumor from many angles. This type of radiation therapy reduces the damage to healthy tissue near the tumor and is being explored in mesothelioma.

INTRAOPERATIVE PHOTODYNAMIC THERAPY: A new treatment that uses special drugs and light to kill cancer cells. Its use in the early states of mesothelioma in the chest is being studied.

INTRAPERITONEALLY: Inserting chemotherapy drugs directly into the abdominal cavity.

INTRAPLEURALLY: Inserting chemotherapy drugs directly into the chest cavity.

INTRAVENOUS: Within a blood vessel.

INVASIVE CANCER: Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

L

LATENCY PERIOD: The time between the actual exposure to a carcinogen like asbestos and the development of cancer, i.e. mesothelioma.

LAWSUIT: A legal action by one person or entity against another person or entity.

LOBECTOMY: A surgical procedure in which the lobe of a lung is removed.

LUNGS: The lungs are a pair of breathing organs located within the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

LUNG CANCER: An uncontrolled growth of abnormal cells in lung tissue. Primary lung cancer originates in the lungs, while metastic lung cancer spreads to the lungs from another organ. Classification is based on the type of cell the cancer originates from: adenocarcinoma, alveolar cell carcinoma, squamous cell carcinoma, large cell, and small cell carcinomas.

LYMPH: Fluid composed of lymphocytes.

LYMPH NODE: A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland. The involvement of lymph glands by mesothelioma changes the stage to a higher one and is an indication of a more advanced tumor.

M

MACROPHAGE: A type of immune cell found in tissues that phagocytizes (engulfs and destroys) particles as part of its function.

MAGNETIC RESONANCE IMAGING (MRI): A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as CT or x-ray. MRI is especially useful for imaging the brain, spine, the soft tissue of joints, and the inside of bones. Also called nuclear magnetic resonance imaging.

MALAISE: Feeling of general discomfort or uneasiness; often the first indication of an infection or other disease.

MALIGNANT: In regard to a tumor, having the properties of cancer that can invade and destroy nearby tissue and that may spread (metastasize) to other parts of the body.

MEDIAN: Middle number in a series of numbers (for example: median survival of 10 months means that for that specific group of patients the survival varied from probably 2 months to 30 months).

MEDIASTINOSCOPY: A procedure in which a tube is inserted into the chest to view the organs in the area between the lungs and nearby lymph nodes. The tube is inserted through an incision above the breastbone. This procedure is usually performed to get a tissue sample from the lymph nodes on the right side of the chest.

MEDIASTINUM: Area of the thoracic cavity between the lungs that contains the heart.

MESOTHELIAL CELLS: Specialized cells forming a tissue called the mesothelium which lines the chest cavity, abdominal cavity, and the cavity around the heart. These cells also cover the outer surface of most internal organs.

MESOTHELIOMA: A form of cancer linked to asbestos exposure that occurs in the sac lining of the chest (pleural mesothelioma) or abdomen (peritoneal mesothelioma), or the lining of the heart (pericardial mesothelioma).

MESOTHELIUM: Tissue formed by specialized cells lining the chest, abdominal cavities and outer surface of most internal organs. The mesothelium produces a lubricating fluid that helps organs by enabling them to move.

METASTASES(S)/METASTASIS: Spread of disease from original site in the body to other sites.

MIXED TYPE MESOTHELIOMA: Cancer involving the epithelial and mesenchymal cells of the mesothelium.

MUTAGEN: A substance that causes mutations (genetic damage).

MUTATION: A change (damage) to the DNA, genes, or chromosomes of living organisms.

N

NARCOTIC: An agent that causes insensibility or stupor; usually refers to opioids given to relieve pain.

NEEDLE BIOPSY: A procedure where a needle is inserted through a bronchoscope or the chest wall to collect tissue or fluid.

NEGLIGENCE: Failure to exercise the care toward others which would reasonably be expected of a person in the circumstances, or taking action which a reasonable person would not.

NEOPLASM: New growth or tumor which may be benign or malignant.

NEUROPATHY: A problem in peripheral nerve function (any part of the nervous system except the brain and spinal cord) that causes pain, numbness, tingling, swelling, and muscle weakness in various parts of the body. Neuropathies may be caused by physical injury, infection, toxic substances, disease (e.g., cancer, diabetes, kidney failure, or malnutrition), or drugs such as anticancer drugs. Also called peripheral neuropathy.

NODULE: Small, solid, slightly raised area.

O

ONCOLOGIST: A physician specializing in cancer diagnosis and treatment.

ONCOLOGY: The study of cancer.

ONSET: In medicine, the first appearance of the signs or symptoms of an illness as, for example, the onset of mesothelioma.

OSHA: The Occupational and Safety Health Administration is the federal government agency which regulates the use of asbestos and sets the standards for its distribution.

OXYGEN: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life.

P

PALLIATIVE TREATMENT: Therapy that relieves symptoms, such as pain or blockage, but is not expected to cure the cancer. Its main purpose is to improve the patient’s quality of life.

PARACENTESIS: Insertion of a thin needle or tube into the abdomen to remove fluid from the peritoneal cavity. Commonly used to make the diagnosis of peritoneal mesothelioma in patients with ascites or to diagnose recurrence of the disease in the belly.

PARIETAL PLEURA: The lining on the inside of the chest wall which is composed of mesothelial cells and is the target organ for asbestos induced mesothelioma.

PATHOGENICITY: Pertaining to the ability to cause disease.

PATHOLOGIST: A specialist physician expert in the origin of disease and the microscopic analysis of body tissues.

PERICARDIUM: The sac that covers the heart.

PERITONEUM: The tissue that lines the abdominal wall which is composed of mesothelial cells and is the target organ for abdominal or peritoneal mesothelioma.

PET SCAN: (Positron Emission Tomography Scan); A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.

PHAGOCYTOSIS: The process of digestion by cells of solid substances; for example, bacteria and foreign particles.

PHENOTYPE: The observable properties of an organism, determined by the genotype in combination with the environment.

PHOTODYNAMIC THERAPY: Treatment with drugs that become active when exposed to light. These drugs kill cancer cells.

PLAINTIFF: The party who initiates a lawsuit by filing a complaint.

PLATELET: A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called a thrombocyte.

PLEURA: The thin covering that protects and cushions the lungs. The pleura is made up of two layers of tissue that are separated by a small amount of fluid. The most common site for mesothelioma.

PLEURAL CAVITY: The space enclosed by the pleura, which is a thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity.

PLEURAL EFFUSION: Accumulation of fluid between the lining of the lung and the chest cavity.

PLEURAL MESOTHELIOMA: Cancer of the pleura (membrane lining the lungs and chest cavity). Pleural mesothelioma is different from lung cancer. Lung cancer refers to any type of malignant tumor that originates in the lungs. Pleural mesothelioma effects the pleura.

The pleura is the tissue lining that surrounds the lungs. There are two pleural membranes that protect the lungs by producing a lubricating fluid that fills the space between the pleura and the lungs.

PLEURAL PLAQUES: A patch or small differentiated area on the surface of the pleura.

PLEURECTOMY: A surgical procedure to remove part of the chest or abdomen lining (pleura) and some of the tissue around it.

PLEURODESIS: A medical procedure that uses chemicals or drugs to cause inflammation and adhesion between the layers of the pleura (the tissue that covers the lungs and lines the interior wall of the chest cavity). This prevents the buildup of fluid in the pleural cavity. It is used as a treatment for severe pleural effusion. It can be performed with a variety of agents, including talc.

PNEUMOCONIOSIS: Fibrosis and scarring of the lungs as a result of repeated inhalation of occupationally associated dust, such as silica, asbestos, and coal dust.

PNEUMONECTOMY: Surgical procedure to remove the entire lung.

PNEUMOTHORAX: Air within the chest cavity.

PROGNOSIS: The likely outcome or course of a disease; the chance of recovery or recurrence.

PROGRESSIVE DISEASE: Cancer that is increasing in scope or severity.

PROTEIN: A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair, and of substances such as enzymes, cytokines and antibodies.

PROTOCOL: An action plan for a clinical trial.

PULMONARY: Having to do with the lungs.

PULMONARY FIBROSIS: Interstitial disease; the presence of fibrous tissue in the lungs.

PULMONARY FUNCTION TESTS: Measures how well the lungs are working and include: spirometry, which measures the amount of air the lungs can hold; lung volume tests to measure the amount of air remaining in the lungs after exhaling; and lung diffusion tests and pulse oximetry, which measure the amount of oxygen passed through the lungs to the blood.

PULMONOLOGIST: A specialist physician expert in the treatment of lung disease.

R

RADIATION THERAPY: Treatment with high-energy rays to destroy or shrink cancer cells.

RADIOLOGY: The use of radiation (such as x-rays) or other imaging technologies (such as ultrasound and magnetic resonance imaging) to diagnose or treat disease.

RELEASE: Document signed to settle claims and get settlement money.

RESECTABLE: Amenable to resection (surgical removal of a diseased portion of a tissue).

RISK FACTOR: Something that increases a person’s chances of developing a disease.

S

SARCOMATOUS MESOTHELIOMA: Type of mesothelioma arising from the mesenchymal cells of the mesothelium.

SERPENTINE ASBESTOS: Asbestos characterized by curly fibers with a layered or tiered structure. Chrysotile, or white asbestos, is a member of the serpentine group and is also the most common form of asbestos.

SETTLEMENT: Resolution of a lawsuit or legal dispute prior to a final court judgment.

SILICA: The chief component of sand and a substance responsible for lung disease and cancer. Silica is not asbestos.

SMALL CELL LUNG CANCER: A type of lung cancer in which the cells are small and round.

SPUTUM: The mucus and other matter brought up from the lungs, bronchi and trachea that one may cough up, spit or swallow. “Sputum” is borrowed directly from the latin “to spit.” It is also called expectoration.

STAGING: The process of finding out whether cancer has spread and if so, how far.

STATE-OF-THE-ART: has several meanings: (1) refers to medical, scientific and technological knowledge that what was reasonably known at the time the product was designed, manufactured or sold; (2) refers to evidence of industry customs, standards, or practices; (3) refers to a defense used by defendants where they claim lack of knowledge of the hazards of asbestos.

STATUTE OF LIMITATIONS: The period after which the right to file a lawsuit expires.

SYNERGISTIC EFFECT: A biologic response to multiple substances where one substance worsens the effect of another substance. The combined effect of the substances acting together is greater than the sum of the effects of the substances acting by themselves. This applies to asbestos and smoking for example.

T

THORACENTESIS: Surgical puncture of the chest wall to remove fluid from the pleural space.

THORACIC: Relating to the chest.

THORACOSCOPY: A surgical technique for tissue sampling in which a telescopic instrument (thoracoscope) fitted with a lighting system is inserted through a puncture in the chest wall. The physician can see the tumor and sample it using a forceps-like tool.

TISSUE: It is a broad term that is applied to any group of cells that perform specific functions.

TLV (Threshold Limit Value): Refers to airborne concentrations of substances and represents a condition under which it is believed that workers may be repeatedly exposed day-after-day without adverse health effects.

TOXIC AGENT: Chemical or physical (for example, asbestos) agents that can cause harmful effects to living organisms.

TOXICOLOGY: Study of poisons.

TREMOLITE: A type of asbestos which has flexible fibers.

TRIAL: The examination of facts and law presided over by a judge with authority to hear the matter.

TUMOR: An abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive. Tumors perform no useful body function. Tumors can be either benign (not cancer) or malignant (cancer).

V

VERMICULITE: A naturally occurring mineral used for insulation, sometimes found contaminated with asbestos.

VISCERAL PLEURA: Portion of the pleura that covers the external surface of the lungs.

W

WHEEZING: A whistling noise in the chest during breathing when the airways are narrowed or compressed.

WHITE BLOOD CELLS (WBC): Refers to a blood cell that does not contain hemoglobin. White blood cells include lymphocytes, neutrophils, eosinophils, macrophages, and mast cells. These cells are made by bone marrow and help the body fight infection and other diseases.

X

X-RAY: High energy radiation with waves shorter than those of visible light. X-rays possess the properties of penetrating most substances (to varying extents), of acting on a photographic film or plate (permitting radiography), and of causing a fluorescent screen to give off light (permitting fluoroscopy). X-rays are used for making images that help to diagnose disease and to treat cancer.