Acne

Acne, eruptive skin disease. It is primarily a disorder of the sebaceous follicles of the skin and appears most often on the face, neck, and back. The natural secretion, or sebum, of the follicles accumulates and mixes with dust and dirt. The follicles and surrounding tissue become inflamed and blackheads appear. If the follicle opening completely closes, the accumulated sebum is degraded by bacteria and forms a cyst.

Acne vulgaris, the most common form, is usually associated with adolescence but may also occur in adults. A severe form of the disorder is known as acne conglobata. Other forms of acne are also observed, such as the chloracne caused by chlorinated compounds. In acne rosacea, the capillaries in the cheeks, forehead, and nose are swollen with blood and the oil glands in the skin become infected.

Acne in adolescence results primarily from hormonal changes taking place in the body; the hormones stimulate sebum production. Outbreaks cannot be prevented by a controlled diet and are not a sign of uncleanliness. Good hygiene should be observed, however, to prevent more serious infections. Severe acne may be treated by antibiotics, benzoyl peroxide, or vitamin A derivatives. Severe acne in adults may be a sign of an underlying endocrine disorder.

Mesothelioma-Pneumoconiosis

Mesothelioma- tumor of body cavity lining: a benign or malignant tumor of the lining of the lungs, heart, or abdomen, often caused by asbestos exposure.

Pneumoconiosis , a general term for any one of several lung diseases caused by breathing dust from industrial occupations like coal mining, sand blasting, and stone cutting (see Occupational and Environmental Diseases). Years of continual exposure to industrial dust can cause the formation of spots (macules), lumps (nodules), or fibrous growths in lung tissue, causing permanent damage or destruction of these tissues. Smoking can complicate or worsen the conditions. Symptoms of the disease include shortness of breath, labored breathing, coughing, and production of phlegm (mucus secreted in the respiratory system when infections are present). Other, often fatal, illnesses such as cancer, tuberculosis, emphysema, or heart disease may also develop.

Both inorganic dust (from minerals) and organic dust (from plants) can produce pneumoconioses. For example, inhalation of inorganic irritants such as coal dust, particularly from mining hard coal, or anthracite, causes the condition known as black lung disease, coal worker’s pneumoconiosis, or anthracosis. Silica dust from quarrying, mining, or sand blasting causes the disease silicosis. The fine particles and dust from asbestos, a fibrous material commonly used in construction and insulation until its use was curtailed by the Environmental Protection Agency in 1989, causes asbestosis and mesothelioma, a cancer of the chest lining. The inhalation of organic irritants most often found in textile mills such as the dusts of cotton, flax, hemp, and jute causes byssinosis, or brown lung disease. Another type of pneumoconiosis takes the form of hypersensitivity to irritants, fumes, and vapors in the workplace from substances like cadmium, beryllium, chlorine, and fluorine.

Treatment can only relieve the symptoms of pneumoconiosis. Treatment options include medication, removal of the patient from the workplace, providing dust control through added ventilation, or the use of personal protection devices like dust masks.

Asbestos

Asbestos (Greek a-,“not”; sbestos, “extinguishable”), the fibrous form of several minerals and hydrous silicates of magnesium. The name may also be applied to the fibrous forms of calcium and iron. Asbestos fibers can be molded or woven into various fabrics. Because it is nonflammable and a poor heat conductor, asbestos has been widely used to make fireproof products such as safety clothing for fire fighters and insulation products such as hot-water piping. The first recorded use of the word asbestos is by Pliny the Elder in the 1st century ad, although the substance itself was known as early as the 2nd century bc. The Romans made cremation cloths and wicks from it, and centuries later Marco Polo noted its usefulness as cloth.

Asbestos is of two principal classes, the amphiboles and the serpentines, the former of relatively minor importance. Chrysotile, in the serpentine class, constitutes about 95 percent of the world supply of asbestos, of which three-fourths is mined in Québec. Other large deposits exist in South Africa. In the United States, California, Vermont, and Arizona are the leading asbestos-producing states; however, the majority of United States deposits are of no commercial value.

Asbestos is obtainable by various underground mining methods, but the most common method is open-pit mining. Only about 6 percent of the mined ore contains usable fibers.

The fibers are separated from the ore by crushing, air suction, and vibrating screens, and in the process are sorted into different lengths, or grades. The most widely used method of grading, the Québec Standard Test Method, divides the fibers into seven groups, the longest in group one and the shortest, called milled asbestos, in group seven. The length of the fibers, as well as the chemical composition of the ore, determines the kind of product that can be made from the asbestos. The longer fibers have been used in fabrics, commonly with cotton or rayon, and the shorter ones for molded goods, such as pipes and gaskets.

Asbestos has been used in building-construction materials, textiles, missile and jet parts, asphalt and caulking compounds and paints, and in friction products such as brake linings. Exposure to asbestos fibers and dust, however, can cause asbestosis, a disease of the lungs caused by the inhalation of asbestos particles, and, after a latent period of up to 30 years and more, various cancers, especially lung cancer and mesothelioma, which is an inoperable cancer of the chest and abdominal lining . At present no wholly satisfactory substitutes are available for asbestos in many of its applications; because of health risks posed by asbestos use, however, research into replacements has been accelerated. In 1986 the Environmental Protection Agency proposed an immediate ban on the major uses of asbestos and a complete ban on all asbestos products within the next decade. This proposal was partially overturned by the U.S. Court of Appeals, which limited the ban to asbestos flooring and new products using asbestos.

Blue Cross

Blue Cross And Blue Shield, network of companies that provide health insurance to people in the United States and Puerto Rico. The Blue Cross and Blue Shield Association, based in Chicago, Illinois, governs the various health insurance organizations that carry its name. Member health insurance companies are operated locally, but they must abide by standards established by the national association. Historically, Blue Cross and Blue Shield insurers have been nonprofit organizations that receive tax-exempt status.

More than 71 million people are members of Blue Cross and Blue Shield health insurance plans. Most Blue Cross and Blue Shield organizations negotiate contracts with local hospitals and physicians to offer services to individuals who have paid premiums (fees) individually or through their employers.

Blue Cross and Blue Shield health insurance plans offer a broad spectrum of coverage options, including fee-for-service plans (also known as indemnity plans) and managed care plans. Fee-for-service plans allow members to visit any doctor or hospital for medical services. Managed care plans require members to visit designated physicians and include health maintenance organizations (HMOs), preferred provider organizations (PPOs), and point-of-service plans (POSs) (see Health Insurance: Types of Plans in the United States). Blue Cross and Blue Shield organizations also administer services for Medicare, a government program that provides coverage for elderly people and for people with certain disabilities

Throughout the 1990s Blue Cross and Blue Shield organizations faced financial difficulties due to the spread of for-profit health-care organizations. Blue Cross and Blue Shield chapters remained nonprofit groups that enrolled subscribers regardless of their individual risk of illness. Its competitors, which used experience rating, were able to recruit more members by charging lower premiums to people with a low risk of illness. Enrollment in Blue Cross and Blue Shield plans dropped drastically in the early 1990s, and many chapters closed.

In 1994 the Blue Cross and Blue Shield Association abolished its requirement that its member groups remain nonprofit organizations. In 1996 Blue Cross of California merged with a for-profit managed care company, WellPoint Health Networks, becoming the first chapter to relinquish its tax-exempt status. During the late 1990s a number of Blue Cross and Blue Shield chapters followed suit and merged with for-profit insurance providers or created new for-profit subsidiaries.

Environmental and Occupational Diseases

Environmental and Occupational Diseases, illnesses caused by exposure to disease-causing agents in the environment, as opposed to illnesses related primarily to an individual's genetic makeup or to immunological malfunctions. In everyday use, the term environmental disease is confined to noninfectious diseases and to diseases caused largely by exposures beyond the immediate control of the individual; the latter restriction eliminates diseases related to personal habits such as smoking or to the use or abuse of medications or drugs such as alcohol. Occupational disease, a major category of environmental disease, refers to illness resulting from job-related exposures.

Historically, awareness of environmental diseases began with the recognition of occupational illnesses, because exposures are usually more intense in work settings than in the general environment and therefore can more readily produce overt illnesses. Examples include silicosis, a lung disease of miners, industrial workers, and potters exposed to silica dust; scrotal skin cancer in chimney sweeps exposed to soot; neurological disease in potters exposed to lead glazes; and bone disease in workers exposed to phosphorus in the manufacture of matches. Many such diseases first gained public attention during the Industrial Revolution in the 19th century.

Environmental diseases

Environmental diseases are caused by chemical agents, radiation, and physical hazards. The effects of exposure, in both natural and work settings, are greatly influenced by the exposure routes: primarily air pollution and water pollution, contaminated food, and direct contact with toxins. Synergistic effects—two or more toxic exposures acting together—are also important, as illustrated by the greatly increased risk of lung cancer in asbestos workers who smoke cigarettes. The potential interaction of multiple hazardous chemicals at toxic waste dumps poses a current public health problem that is of unknown dimensions.

Chemicals

Industrial society has introduced or increased human exposure to thousands of chemicals in the environment. Examples are inorganic materials such as lead, mercury, arsenic, cadmium, and asbestos, and organic substances such as polychlorinated biphenyls (PCBs), vinyl chloride, and the pesticide DDT. Of particular concern is the delayed potential for these chemicals to produce cancer, as in the cases of lung cancer and mesothelioma caused by asbestos, liver cancer caused by vinyl chloride, and leukemia caused by benzene. Minamata disease, caused by food contaminated with mercury, and Yusho disease, from food contaminated with chlorinated furans, are examples of acute toxic illnesses occurring in nonoccupational settings.

The full toxic potential of most environmental chemicals has not been completely tested. The extent and frequency of an illness are related to the dose of toxin, in degrees depending on the toxin. For chronic or delayed effects such as cancer or adverse reproductive effects, no “safe” dose threshold may exist below which disease is not produced. Thus, the cancer-producing potential of ubiquitous environmental contaminants such as DDT or the PCBs remains undefined.

Radiation

Ionizing and nonionizing radiation can produce both acute and chronic health effects, depending on dose levels. The effects of nonionizing radiation at lower dose levels are uncertain at present. Ionizing radiation at high doses causes both acute disease and delayed effects such as cancer. Victims include workers exposed to various occupational use of X rays or radioactive materials. Although the disease-producing potential of ionizing radiation at low doses is also uncertain, an increase in chromosome damage has been observed in workers in nuclear shipyards.

Physical Hazards

Major physical hazards include traumatic injuries and noise. Trauma arising from unsafe environments accounts for a large proportion of preventable human illness, and noise in the workplace is responsible for the most prevalent occupational impairment: hearing loss or permanent deafness.

FORMS OF ENVIRONMENTAL DISEASE
Environmental diseases can affect any organ system of the body. How the diseases are expressed depends on how the particular environmental agent enters the body, how it is metabolized, and by what route it is excreted. The skin, lungs, liver, kidneys, and nervous system are commonly affected by different agents in different settings. Of particular concern is the capacity of many environmental agents to cause various cancers, birth defects or spontaneous abortions (through fetal exposure), and mutations in germ cells, the last-named raising possibilities of environmentally caused genetic diseases in later generations.

Environmental illnesses can be mild or severe and can range from transient to chronic, depending on the doses of toxin received. Some diseases occur abruptly after a toxic exposure, whereas the time of onset of other diseases varies after exposure. Environmentally induced cancers, for example, commonly involve latency periods of 15 to 30 years or more. Those illnesses that occur directly after a distinct toxic exposure are usually easily identified as being environmentally or occupationally caused. If the exposure is not clear-cut or illness is delayed, however, the cause is difficult to identify, as clinical features alone are usually nonspecific. In addition, many different causes, environmental or otherwise, may produce identical illnesses. In such instances, epidemiological studies of exposed populations can help relate exposures to the illnesses they cause.

OCCURRENCE

Total frequencies of environmental illness are difficult to measure because of the reasons just described. When causes can be identified, however, scientists observe that frequencies of occurrence of a particular illness vary directly with the severity and extent of exposure. Particularly frequent in the workplace are skin lesions from many different causes and pulmonary diseases related to the inhalation of various dusts, such as coal dust (black lung), cotton dust (brown lung), asbestos fibers (asbestosis), and silica dust (silicosis). Environmental agents can also cause biological effects without overt clinical illness (for example, chromosome damage from irradiation). The health significance of such subclinical changes is not yet clear.

AGENCIES AND LAWS

The regulation of workplace practices and of potential environmental pollution has evolved as the use of chemicals and human exposure to potential toxins have grown more widespread and complex in modern society. In the United States, numerous laws are directed at protecting occupational and environmental health. Most were passed since 1960, including the Occupational Safety and Health Act of 1970 and the Resource Conservation and Recovery Act of 1979. Means for the rapid cleanup of toxic waste dumps were provided in the Comprehensive Environmental Response, Compensation, and Liability Act of 1980.

Federal agencies responsible for enforcing such environmental and occupational health laws consist principally of the Environmental Protection Agency and the Occupational Safety and Health Administration (OSHA) within the Department of Labor. The Food and Drug Administration, within the Department of Health and Human Services (HHS), and the Department of Agriculture have regulatory responsibility for preventing the contamination of food supplies. Federal field investigations of potential environmental and occupational hazards are handled through the Center for Environmental Health and the National Institute for Occupational Safety and Health, which are components of the Centers for Disease Control, within HHS. General environmental health research and toxicological testing are directed through the National Institutes of Health and the National Toxicology Program, also within HHS. Comparable regulations and agencies at state and local levels, working with their federal counterparts, play a crucial role as well.

International coordination of environmental and occupational control activities in many countries is guided through the World Health Organization. In the developing parts of the world, such activities are of critical importance as modern industrialization proceeds in the face of poverty and growing populations