Effects of Alcohol

The effects of Alcohol are summarized in terms of Blood Alcohol Concentration (%) as against its effects.

Blood Alcohol concentration (%)		Effects
0.02	Mild alteration of feelings, slight intensification of moods.
0.05	Feelings of relaxation, giddiness, lowered inhibitions. Judgment and motor skills are both slightly impaired.
0.08	Muscle coordination and reaction time impaired. Face, hands, arms, and legs may tingle and then feel numb. Legally intoxicated in Canada and some U.S. states.
0.10	Clumsiness, uncoordinated behavior. Impairment of mental abilities, judgment, and memory. Legally intoxicated in most U.S. states.
0.15	Irresponsible behavior, euphoria. Some difficulty standing, walking, and talking.
0.20	Motor and emotional control centers measurably affected. Slurred speech, staggering, loss of balance, and double vision can all be present.
0.40	Drinker is usually unconscious.
0.45	Respiration slows and can stop altogether.
0.50	Death can result.
Source: National Safety Council and California Department of Alcohol and Drug Programs

 

As can be observed above, the effects of alcohol as shown in the blood alcohol concentration indicates that the higher the concentration the greater the risk of discomfort, unconsciousness and possibly death at the worst.

 

Effects of Aging

Gerontologists study the social and behavioral effects of aging. The biological effects of aging, such as the loss of flexibility in some tissues and the decline of organ function, can influence these social and behavioral effects. For example, the heart becomes less efficient as a person ages, making exercise more difficult.

Organ or System	Natural Effects of Aging	Accelerating Factors
Skin	Loses thickness and elasticity (wrinkles appear)	Process accelerated by smoking, excessive exposure to sun
	Bruises more easily as blood vessels near surface weaken
Brain/Nervous System	Loses some capacity for memorization and learning as cells die	Process accelerated by overuse of alcohol and other drugs, repeated blows to the head
	Becomes slower to respond to stimuli (reflexes dull)
Senses	Become less sharp with loss of nerve cells	Process accelerated by smoking, repeated exposure to loud noise
Lungs	Become less efficient as elasticity decreases	Process accelerated by smoking, poor air quality, insufficient exercise
Heart	Pumps less efficiently, making exercise more difficult	Process accelerated by overuse of alcohol and tobacco, poor eating habits
Circulation	Worsens, and blood pressure rises, as arteries harden	Process accelerated by injury, obesity
Joints	Lose mobility (knee, hip) and deteriorate from constant wear and pressure (disappearance of cartilage between vertebrae results in old age ‘shrinking’)	Process accelerated by injury, obesity
Muscles	Lose bulk and strength	Process accelerated by insufficient exercise, starvation
Liver	Filters toxins from blood less efficiently	Process accelerated by alcohol abuse, viral infection

 

In view of the above, it is obvious that a healthy lifestyle and exercise especially during the early stages of development and maturity  could minimize where necessary some of the problems and effects of aging.

 

Effects of Aging on the Mind

One of the myths of aging is that intelligence diminishes with age. Early studies that used intelligence tests designed for children revealed that older people scored lower than young adults. However, these tests relied heavily on skills commonly used in school classrooms, such as arithmetic, and required the test to be completed within a specific time limit. Older people may require more time to answer questions, and more recent studies based on untimed tests and other measures of intellectual activity, such as problem solving and concept formation, show that there is relatively little decline in mental ability in healthy people at least up to age 70.

The aging brain does undergo a progressive loss of neurons, or nerve cells, but these losses represent only a small percentage of neurons in the brain. The speed of conduction of a nerve impulse declines with age, but it drops only about 15 percent over the age span from 30 to 85 years. Although intelligence is generally not affected by the aging process, studies show that some older people may find it difficult to deal with many stimuli at once. For example, an older individual requires more time to sort out all of the information when many highway signs come into view simultaneously. Traveling at 97 km/h (60 mph), an elderly driver may miss the information he or she needs or may act on the wrong information. But if older individuals recognize this limitation and adjust their behavior accordingly, they can continue driving safely well into old age.

Many older people experience problems with memory, and up to 10 percent of the elderly have memory problems significant enough to interfere with their ability to function independently. Memory problems were once considered an inevitable effect of the aging process, but researchers have determined that many of the brain-related changes often observed in elderly people, including memory loss, are actually a result of such diseases as Alzheimer’s disease and diseases associated with blood vessels and blood flow in the brain, such as stroke. Memory loss is sometimes treatable, and certain memory-aiding strategies have been found to help reverse the short-term memory loss experienced by many older people.

Another myth about aging is that people tend to grow sour and mean-spirited with age. Research shows that personalities really do not change much over time. A mean-spirited, grumpy old person was probably that way when he or she was 30. And, as humans age, most still like to do the things they did when they were young. For example those who were athletic in their youth may continue to enjoy athletic activities as they age.

An older person’s social environment, however, can have a marked impact on personality. The social isolation that often exists among older people can dramatically influence mental attitudes and behavior. In the United States, 33 percent of all older people live alone, most of them widowed women over the age of 85. About 5 percent of elderly Americans live in some type of long-term care facility, and almost 25 percent of all older Americans live under or near the federal poverty level. These people have little or no money for recreational activities. This poverty and isolation often leads to clinical depression and other problems, such as alcoholism.

 

Effects of Aging on the Human Body

Several general changes take place in the human body as it ages: hearing and vision decline, muscle strength lessens, soft tissues such as skin and blood vessels become less flexible, and there is an overall decline in body tone.

Most of the body’s organs perform less efficiently with advancing age. For example, the average amount of blood pumped by the heart drops from about 6.9 liters (7.3 quarts) per minute at age 20 to only 3.5 liters (3.7 quarts) pumped per minute at age 85. For this same age range, the average amount of blood flowing through the kidneys drops from approximately 0.6 liters (0.6 quarts) per minute to 0.3 liters (0.3 quarts). Not all people experience decreased organ function to the same degree—some individuals have healthier hearts and kidneys at age 85 than others do at age 50.

The immune system also changes with age. A healthy immune system protects the body against bacteria, viruses, and other harmful agents by producing disease-fighting proteins known as antibodies. A healthy immune system also prevents the growth of abnormal cells, which can become cancerous. With advancing age, the ability of the immune system to carry out these protective functions is diminished—the rate of antibody production may drop by as much as 80 percent between age 20 and age 85. This less-effective immune system explains why a bout of influenza, which may make a young adult sick for a few days, can be fatal for an elderly person. Thus, it is as important for an older person to be vaccinated against the flu and pneumonia as it is for young people to be vaccinated against childhood diseases.

Most of the glands of the endocrine system, the organs that secrete hormones regulating such functions as metabolism, temperature, and blood sugar levels, retain their ability to function into advanced age. However, these glands often become less sensitive to the triggers that direct hormone secretion. In the aging pancreas, for example, higher blood sugar levels are required to stimulate the release of insulin, a hormone that helps the muscles convert blood sugar to energy.

The ovaries and the testes, the endocrine glands that regulate many aspects of sexual reproduction, alter during the aging process. As a man ages, the testes produce less of the male sex hormone, testosterone. A woman’s ovaries undergo marked changes from about age 45 to age 55 during a process known as menopause. The ovaries no longer release egg cells, and they no longer generate the hormones that stimulate monthly menstrual cycles. After women have gone through menopause, they are no longer capable of having children without the aid of reproductive technology. The physical changes associated with aging do not have a significant impact on sexual activity—most healthy people maintain an interest in sex all of their lives.

 

Effects of Acid Rain on Human Health

Effects of Acid Rain on Human Health

The acidification of surface waters causes little direct harm to people. It is safe to swim in even the most acidified lakes. However, toxic substances leached from soil can pollute local water supplies. In Sweden, as many as 10,000 lakes have been polluted by mercury released from soils damaged by acid rain, and residents have been warned to avoid eating fish caught in these lakes. In the air, acids join with other chemicals to produce urban smog, which can irritate the lungs and make breathing difficult, especially for people who already have asthma, bronchitis, or other respiratory diseases. Solid particles of sulfates, a class of minerals derived from sulfur dioxide, are thought to be especially damaging to the lungs.

 

 

Defining AIDS

Defining AIDS

The CDC presented its first definition of AIDS in 1982. The CDC recommended that physicians diagnose AIDS if a person has an illness known to be caused by immune deficiency, as long as there is no known cause for this immune deficiency. (Radiation therapy for cancer and certain drugs also may impair the immune system). As more information became known about the course of HIV infection and the nature of the virus itself, this definition of AIDS was revised repeatedly to expand the list of illnesses considered diagnostic indicators of the disease. Early definitions were based on the opportunistic infections commonly found in HIV-infected men. As a result, many women who did not have symptoms covered in the official AIDS definition were denied disability benefits and AIDS-related drug therapies.

The current definition of AIDS was created in 1993 and includes 26 opportunistic infections and cancers, known as diagnostic indicators, which affect both men and women. The definition also emphasizes the importance of the level of CD4 cells in the blood. Today doctors make the diagnosis of AIDS in anyone with a CD4 count below 200 cells per micro-liter of blood, regardless of the associated illnesses they may have.

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Causes of Aging

Although the exact causes of aging remain unknown, scientists are learning a great deal about the aging process and the mechanisms that drive it. Some of the most promising research on the aging process focuses on the microscopic changes that occur in all living cells as organisms age. In 1965 American microbiologist Leonard Hayflick observed that under laboratory conditions, human cells can duplicate up to 50 times before they stop. Hayflick also noted that when cells stop normal cell division (see Mitosis), they start to age, or senesce. Since Hayflick’s groundbreaking observations, scientists have been searching for the underlying cause, known as the senescent factor (SF), of why cells stop dividing and thus age.

Different theories have been proposed to explain how SF works. One theory is based on the assumption that aging, and diseases that occur more frequently with advancing age, are caused by structural damage to cells. This damage accumulates in tiny amounts each time the cell divides, eventually preventing the cell from carrying out normal functions.

One cause of this damage may be free radicals, which are chemical compounds found in the environment and also generated by normal chemical reactions in the body. Free radicals contain unpaired electrons and so carry an electric charge that makes them highly reactive. In an effort to neutralize their electric charge, free radicals constantly bombard cells in order to steal electrons in a process called oxidation. Free radicals are thought to greatly increase the severity of—or perhaps even cause—such life-shortening diseases as diabetes mellitus, strokes, and heart attacks. Researchers have observed that free radicals exist in smaller amounts in those species with relatively long life spans. Increasing human life span may depend on our ability to prevent free radical damage, and scientists are currently examining the role of chemical compounds, called antioxidants, that prevent or reverse oxidative damage in the aging process.

Another theory suggests that SF is genetically regulated—that is, cells are genetically programmed to carry out about 50 cell divisions and then die. Researchers have identified at least three genes that are involved with human cellular senescence. They have also discovered a protein on the surface membranes of senescent cells that inhibits production of deoxyribonucleic acid (DNA), the essential molecule that carries all genetic information.

Another theory proposes that extra, useless bits of DNA accumulate over time within a cell’s nucleus. Eventually this so-called junk DNA builds up to levels that clog normal cell action. If this idea is correct, scientists may be able to find ways to prevent accumulation of junk DNA, thereby slowing down the process of senescence in cells.

Other studies focus on cell division limits. Each time a cell divides, it duplicates its DNA, and in each division the sections at the ends of DNA, called the telomeres, are gradually depleted, or shortened. Eventually the telomeres become so depleted that normal cell division halts, typically within 50 cell divisions. Scientists have found that an enzyme produced by the human body, called telomerase, can prolong the life of the telomeres, thus extending the number of cell divisions. In laboratory studies, cells injected with telomerase continue to divide well beyond the normal limit of 50 cell divisions. These promising results have triggered worldwide attention on telomerase and its relationship to aging.

A number of other studies are underway to investigate the effects of aging. Scientists have found, for example, a possible explanation for why women have longer average life spans than men. The difference seems to be biologically determined, and male and female sex hormones are probably responsible. The blood levels of female sex hormones drop sharply during menopause. At that time, the incidence of heart disease and high blood pressure in women increases to match the incidence in men, suggesting that the presence of female sex hormones offers some protection against heart disease.

Biochemistry in 1989: Genetic Engineering (Engineered Virus)

Researchers at Cornell University in Ithaca, N.Y., began the first open-air test of a genetically engineered virus in July. They sprayed the virus, one of a family of insect parasites called baculoviruses, on a cabbage field at Cornell’s experimental station in Geneva, N.Y., in an attempt to protect the plants from the cabbage looper caterpillar.

The researchers hope eventually to make a more potent form of the virus that will kill the caterpillars quickly, but they fear that such a potent virus could be harmful to the environment. As a first step, therefore, molecular biologist H. Alan Wood and colleagues removed from the virus a gene responsible for producing a protein that prevents the virus from being damaged by sunlight and weather. In the absence of the gene, Wood said, the virus would die out over a period of about two years. If the baculovirus does, in fact, die out, scientists will then assume that they can safely engineer it to make it more potent.

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Biochemistry in 1989: Genetic Engineering (Experimental AIDS Vaccines)

Almost two years of testing showed that a genetically engineered AIDS vaccine is safe in humans, the vaccine’s maker, MicroGeneSys, Inc., of West Haven, Conn., said in June. The continuing trial involved more than 120 gay and bisexual men who tested negative for infection with HIV, the virus that causes AIDS, when the tests were begun in 1987. Aside from the mild side effects normally seen with vaccines, the AIDS vaccine, which contains proteins found on the surface of HIV, produced no toxic effects. The initial testing was to determine whether the vaccine was safe; trials to determine whether the vaccine can actually prevent AIDS were begun shortly after the vaccine’s safety was assured.

In a separate development, Jonas Salk of the Salk Institute for Biological Sciences in San Diego announced at the Fifth International Conference on AIDS in Montreal in June that three chimpanzees injected with a potential AIDS vaccine developed strong immune responses. Instead of HIV surface proteins, Salk’s preparation uses whole killed viruses, an approach he followed in developing his famous polio vaccine. The potential AIDS vaccine caused no adverse effects when tested for safety in 19 human volunteers.

Biochemistry in 1989: Genetic Engineering (Erythropoietin for Anemia)

In June the U.S. Food and Drug Administration (FDA) approved the marketing of a genetically engineered form of erythropoietin (EPO) for use in treating anemia in patients with severe kidney disease. EPO is a hormone produced in the kidney that stimulates the growth of red blood cells. The new drug, epoetin alfa (sold under the name Epogen), was expected to benefit many of the more than 90,000 people in the United States who regularly undergo dialysis to remove toxic chemicals from their blood because their kidneys have failed. Dialysis destroys red blood cells, making the patients anemic. Also, many dialysis patients require frequent transfusions, which lead to a toxic buildup of iron (from destroyed red cells) in their blood; EPO should ease that problem.

Later in June the FDA gave limited approval for another use of EPO. The drug was authorized as an ‘investigational new drug for treatment,’ for use in people with AIDS who suffer from anemia, either from the virus that causes the disease or because they are taking zidovudine (previously called AZT) to control the disease’s progression. Zidovudine kills red blood cells, and EPO helps to replace them.