Birth Control

Birth Control or Contraception, deliberate prevention of pregnancy using any of several methods. Birth control prevents a female sex cell (egg) from being fertilized by a male sex cell (sperm) and implanting in the uterus. In the United States, about 64 percent of women aged 15 to 44 years practice some form of birth control. When no birth control is used, about 85 percent of sexually active couples experience a pregnancy within one year.

TYPES OF BIRTH CONTROL

Barrier Methods

Barrier methods physically block sperm from entering the uterus to unite with an egg. Barrier methods must be used with each act of sexual intercourse. While they are easy to use, some people feel barrier methods are inconvenient because they interfere with sexual spontaneity. Barrier methods include male and female condoms, the diaphragm, the cervical cap, and spermicides.

Male Condom -> The male condom is a thin sheath made of latex, polyurethane, or less commonly, animal membrane, that fits over an erect penis. During ejaculation (when semen ejects from the penis), the condom catches and holds sperm before it can travel into a woman’s uterus. After each act of sexual intercourse the condom is removed and thrown away. The condom is inexpensive, easy to use, and does not require a prescription. It has no known side effects, although those people who are sensitive or allergic to latex should use polyurethane condoms.

Female Condom -> The female condom, available without a prescription, is an elongated polyurethane sac. A woman inserts the closed end of the sac into the vagina to cover the cervix (the opening of the uterus) and prevent sperm from entering the uterus. The open end of the sac remains outside the vagina for the penis to enter. Like the male condom, the female condom must be thrown away after use and a new one used for each act of intercourse. With typical use, the female condom is 79 percent effective in preventing pregnancy. It also reduces the risk of many STIs. Some people experience genital irritation from the female condom.

Diaphragm -> The diaphragm is a shallow, molded cup of thin rubber with a flexible rim. Before intercourse, spermicide must be placed inside the cup and around the inside of the rim of the diaphragm. The woman then inserts the diaphragm into her vagina so that it covers the cervix, preventing the passage of sperm from the vagina to the uterus. The spermicide kills any sperm that are able to pass by the diaphragm. Diaphragms come in various sizes to fit the cervix. They are available only from health-care professionals who ensure that the device fits properly. With typical use, the diaphragm is about 80 percent effective in preventing pregnancy.

Cervical Cap -> The cervical cap is made of flexible latex rubber and shaped like a thimble. It is smaller than a diaphragm and fits more tightly onto the cervix, where it is held in place by suction. Like the diaphragm, the cervical cap must be fitted by a health-care professional and it should also be used with a spermicide. With typical use, the cervical cap is about 80 percent effective in preventing pregnancy in women who have not given birth, and about 60 percent effective in those who have given birth.

Spermicides -> Spermicides are jellies, creams, foams, suppositories, tablets, or films that block the entrance to the cervix and contain a sperm-killing chemical. They can be purchased without a prescription and used alone or with a condom, diaphragm, or cervical cap. Spermicides used alone must be inserted deep into the vagina before each act of intercourse and a woman should not douche for six to eight hours after intercourse. With typical use, spermicides used alone are effective in preventing pregnancy about 74 percent of the time. They may cause an allergic reaction such as irritation of the vagina or penis.

Intrauterine Device

The intrauterine device (IUD) is a small plastic device inserted into a woman’s uterus to prevent pregnancy. IUDs prevent pregnancies through a number of mechanisms: they interfere with the movement of sperm and egg, they decrease the ability of sperm to fertilize an egg, or, rarely, they prevent a fertilized egg from implanting in the lining of the uterus.

An IUD must be inserted and removed by a health-care professional. Depending on the device, it must be replaced every one to ten years. A plastic string attached to the IUD hangs down through the cervix, enabling a woman to check regularly that the IUD is properly positioned. With typical use, the IUD is about 96 percent effective in preventing pregnancy. The device may increase menstrual bleeding or cause irregular bleeding or cramping. The IUD has also been associated with an increased risk for pelvic inflammatory disease (PID), an infection of the reproductive tract. However, most cases of PID that occur in women with IUDs are attributable to an STI. Other possible problems associated with IUD use include perforation of the uterus and embedding of the IUD in the uterus. In rare cases an ectopic pregnancy occurs, a serious medical complication in which a fertilized egg implants outside of the uterus.

Hormonal Contraceptives

Hormonal contraceptives deliver doses of female sex hormones that alter a woman’s reproductive cycle in one or more ways. When absorbed by the body, these hormones may interfere with ovulation to prevent the maturation and release of an egg from the ovaries; thicken the cervical mucus, which interferes with sperm movement; alter the rate at which the egg moves through the fallopian tubes to prevent sperm from meeting the egg; or change the condition of the uterine lining to prevent fertilized eggs from implanting in it.

Surgical Sterilization

Methods of surgical sterilization—vasectomy for men and tubal sterilization for women—are almost 100 percent effective in preventing pregnancy. These procedures are permanent forms of birth control. Although surgical techniques may be used to reverse vasectomy or tubal sterilization in some cases, no one should undergo sterilization with the expectation that it can later be reversed. A vasectomy or a tubal sterilization does not protect against STIs.

A vasectomy is performed in a doctor’s office or clinic using local anesthesia. In this minor surgical procedure, each of the two vas deferens (ducts that carry sperm from the testes to the penis) is cut and the ends are tied off to prevent sperm from reaching the penis.

Emergency Contraception

Emergency contraception refers to methods that a woman can use after unprotected intercourse to prevent fertilization of the egg or implantation of the fertilized egg in the uterus. Two methods are available: emergency contraceptive pills or emergency insertion of an IUD.

Emergency contraceptive pills, commonly called morning-after pills, are similar to birth control pills but they contain a higher dose of hormones. A health-care professional prescribes the pills and they are usually taken in two doses, 12 hours apart. With typical use, emergency contraceptive pills are 79 to 85 percent effective when a woman takes the pills within 72 hours of unprotected intercourse. Depending on where a woman is in her menstrual cycle at the time she takes these contraceptives, the pills will either inhibit or delay ovulation, or they may alter the uterine lining, preventing implantation of a fertilized egg.

The insertion of an IUD within seven days of unprotected intercourse is 99 percent effective in preventing pregnancy with typical use. A trained health-care professional must insert the device, which is guided into the vagina and then through the cervix into the uterus. The IUD interferes with sperm movement and the ability of a fertilized egg to implant in the uterine lining.

Fertility Awareness Methods

Fertility awareness methods are a collection of practices that help a woman know which days of the month she is most likely to get pregnant. A woman is most fertile during a period that ranges from five days before ovulation to two days after ovulation. A woman can learn when she is ovulating by observing her body and charting physical changes. During the days surrounding ovulation, she can then abstain from sexual intercourse (known as periodic abstinence or natural family planning) or use a barrier method of contraception during intercourse. With typical use, fertility awareness methods are generally about 80 percent effective in preventing pregnancy. Fertility awareness methods are most reliable for women with regular menstrual cycles. As a woman becomes more familiar with the signs of ovulation and the pattern of her menstrual cycle, fertility awareness methods become more effective.

Bipolar Disorder

Bipolar Disorder is a mental illness in which a person’s mood alternates between extreme mania and depression. Bipolar disorder is also called manic-depressive illness. When manic, people with bipolar disorder feel intensely elated, self-important, energetic, and irritable. When depressed, they experience painful sadness, negative thinking, and indifference to things that used to bring them happiness.

Bipolar disorder usually begins in a person’s late teens or 20s. Men usually experience mania as the first mood episode, whereas women typically experience depression first. Episodes of mania and depression usually last from several weeks to several months. On average, people with untreated bipolar disorder experience four episodes of mania or depression over any ten-year period. Many people with bipolar disorder function normally between episodes. In “rapid-cycling” bipolar disorder, however, which represents 5 to 15 percent of all cases, a person experiences four or more mood episodes within a year and may have little or no normal functioning in between episodes. In rare cases, swings between mania and depression occur over a period of days.

CAUSES

The genes that a person inherits seem to have a strong influence on whether the person will develop bipolar disorder. Studies of twins provide evidence for this genetic influence. Among genetically identical twins where one twin has bipolar disorder, the other twin has the disorder in more than 70 percent of cases. But among pairs of fraternal twins, who have about half their genes in common, both twins have bipolar disorder in less than 15 percent of cases in which one twin has the disorder. The degree of genetic similarity seems to account for the difference between identical and fraternal twins. Further evidence for a genetic influence comes from studies of adopted children with bipolar disorder. These studies show that biological relatives of the children have a higher incidence of bipolar disorder than do people in the general population. Thus, bipolar disorder seems to run in families for genetic reasons.

TREATMENT

Different therapies may shorten, delay, or even prevent the extreme moods caused by bipolar disorder. Lithium carbonate, a natural mineral salt, can help control both mania and depression in bipolar disorder. The drug generally takes two to three weeks to become effective. People with bipolar disoder may take lithium during periods of relatively normal mood to delay or prevent subsequent episodes of mania or depression. Common side effects of lithium include nausea, increased thirst and urination, vertigo, loss of appetite, and muscle weakness. In addition, long-term use can impair functioning of the kidneys. For this reason, doctors do not prescribe lithium to bipolar patients with kidney disease. Many people find the side effects so unpleasant that they stop taking the medication, which often results in relapse.

From 20 to 40 percent of people do not respond to lithium therapy. For these people, two anticonvulsant drugs may help dampen severe manic episodes: carbamazepine (Tegretol) and valproate (Depakene). The use of traditional antidepressants to treat bipolar disorder carries risks of triggering a manic episode or a rapid-cycling pattern.

Ascorbic Acid

Ascorbic Acid or Vitamin C, a food substance needed by humans to prevent scurvy, a disease of the gums, bones, and blood vessels, and to increase the body’s resistance to infection. Ascorbic acid acts as an antioxidant, a nutrient that chemically binds and neutralizes the tissue-damaging effects of substances in the environment known as free radicals. As a result, ascorbic acid is vital for the growth and maintenance of healthy bones, teeth, gums, ligaments, and blood vessels. Because of its role in the formation of collagen, the body’s major building protein, ascorbic acid is a central component of all body organs.

Ascorbic acid occurs naturally in many fruits and vegetables, particularly in tomatoes, citrus fruits, cantaloupe, broccoli, spinach, green peppers, cabbage, and potatoes. The vitamin is easily destroyed by cooking or canning foods and by exposure to air and light. A healthy diet generally contains sufficient quantities of ascorbic acid, but the body requires more of the vitamin after serious injury, major surgery, burns, and when exposed to extremes of temperature. At risk for ascorbic acid deficiency are smokers, women taking contraceptives containing the female sex hormone estrogen, and people who live in cities with high levels of carbon monoxide from traffic. There is conflicting evidence that taking large doses of ascorbic acid will either prevent the common cold or reduce the severity of its symptoms.

Ascorbic acid is an organic compound of carbon, hydrogen, and oxygen. Pure ascorbic acid is a white solid, and is made synthetically from the sugar dextrose. It is used both in vitamin supplements and as a food preservative.

Aphasia

Aphasia (Greek a, “not”; phanai, “to speak”), term introduced by the French physician Armand Trousseau to denote inability to express thought by means of speech, as a consequence of certain brain disorders. The meaning has since been extended to cover loss of the faculty of interchanging thought, so that it may even denote a temporary but complete loss of memory.

Motor aphasia involves a loss of memory of the coordinated movements necessary for the formation of symbols. This usually includes gestures, speech, and writing. (The inability to write is commonly termed agraphia.) Victims of this disorder are unable to name any object shown to them, although they know what it is. Neither can they reply to any question although they may understand it. In sensory aphasia, a loss of memory of the meaning of symbols occurs. This may affect the recollection of spoken language. The victim can hear every sound but cannot understand a single spoken word.

Antiretroviral Therapy

Understanding the specific steps in the HIV replication cycle is critical in order for scientists to develop drugs that attack vulnerable stages within the cycle. HIV belongs to a unique group of viruses known as retroviruses, so named because these viruses reverse the usual flow of genetic information within an infected cell. Most viruses store their genetic material in deoxyribonucleic acid (DNA), the double-helix structure that makes up genes. When a virus infects a cell, the viral DNA forms the template for the creation of messenger RNA, a type of ribonucleic acid. This messenger RNA directs the formation of specific proteins, and these proteins, in turn, build new virus particles (see Genetics). In HIV, however, genetic material is stored in two single-stranded RNA molecules. When HIV infects a cell, an enzyme called reverse transcriptase copies the genetic instructions in the virus’s RNA and moves it into the DNA. This movement of genetic information from RNA to DNA is the opposite of that which occurs in most cells during protein synthesis.

Another HIV enzyme, called integrase, helps the newly formed viral DNA to become part of the structure of the infected cell’s DNA. The viral DNA then forces the infected cell to manufacture HIV particles. A third HIV enzyme, called protease, packages these HIV particles into a complete and functional HIV virus. Over the last decade researchers have created a variety of drugs that block the action of some of the enzymes used in HIV replication. The main classes of drugs used against HIV are nucleoside analogues, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, and fusion inhibitors.