Sexual Health, Preserving Reproduction
What we talk about when we talk about sex. It is difficult to find a health topic with more varied elements. Embodied in sex are concerns about fertility, reproduction, and sexually transmitted disease, where there are clear pathologies. But also embodied in sex are a wide range of concerns that involve emotional wellbeing and quality-of-life issues. And in some cases, there is considerable overlap between the two.
Testosterone: do male hormones make the man?Testosterone is the principal sex hormone in males, responsible for the maturation of sex organs, production of sperm, growth of body and facial hair, increased muscle mass, and a deepening voice. Testosterone, which also plays other metabolic roles in the body, is produced in small amounts by the adrenal glands in both males and females and by the ovaries in females (women produce 10% the amount of testosterone as men). READ MORE
Testosterone is produced in the testes by Leydig cells, which are abundant prior to birth and during the neonatal period, when they produce testosterone needed for the development of male genitalia. The number of Leydig cells then declines until puberty, when testosterone is then called on to fuel the development of secondary sexual characteristics; testosterone also affects fat distribution and maintains bone density.
Testosterone levels fluctuate throughout the day, peaking in the early morning hours (about 4:00 to 8:00 am), and dipping to their lowest levels 12 hours later, (about 4:00 to 8:00 pm). Levels also increase after exercise. Testosterone peaks during adolescence and early adulthood. As a man ages, testosterone levels decline, typically about 1% a year after age 30.
Low levels (hypogonadism) in males may be due to pituitary disease, genetic disorders or testicular damage caused by alcoholism, physical injury or viral disease like mumps; performance-enhancing drugs, such as steroids, can also decrease testosterone levels. High levels may indicate testicular or adrenal tumors, hyperthyroidism. In women, higher than normal testosterone levels may indicate ovarian or adrenal gland tumors or polycystic ovarian syndrome.
A testosterone test may be ordered when male infertility is suspected or if the patient has a decreased sex drive or erectile dysfunction; other symptoms of low testosterone can include lack of beard and body hair, decreased muscle mass, and enlarged breasts (gynecomastia).
Even in the absence of any symptoms, however, testosterone therapy is increasingly popular among men, as well as many women. The prospects are tantalizing: a boost to libido, increased muscle mass, sharper memory, better concentration, and more energy. For middle-aged (and older) individuals, testosterone therapy may sound like the ultimate anti-aging formula. Yet the benefits of testosterone therapy aren't as clear as they may seem and there are risks, which is why treating normal aging with testosterone is likely to remain controversial. LESS
Estrogen: from fertility to menopause and afterREAD MORE
Estrogen tests may be used for a variety of reasons; more than 20 forms of estrogen have been identified, but estrone (E1) and estradiol (E2) are the two main estrogens in non-pregnant females, and estriol (E3) is the main pregnancy hormone. (Progesterone is another major female hormone that also plays key roles in pregnancy and menstruation.) Estrogens are tested if a girl or woman shows symptoms of a hormone imbalance, abnormal vaginal bleeding, unusual or early sex organ development; they are also monitored during pregnancy, especially early stages. Abnormally high or low levels of estrogens may be the result of many different factors, including thyroid or pituitary abnormalities.
Levels will vary on a daily basis throughout the menstrual cycle, which is why patterns, rather than single values, are most important. High levels may accompany tumors of the ovary, hyperthyroidism and cirrhosis (or, in males, tumors of the testes). Low levels may reflect various genetic disorders, including Down syndrome, stress or extreme endurance exercise. Certain medications can also raise or lower estrogens levels.
For many years, millions of women entering menopause in America were prescribed hormone replacement therapy (HRT) to alleviate menopausal symptoms, as well as protect against heart disease and maintain strong bones and youthful skin. In 2002, a series of research studies suggested that HRT was not as protective or as safe as once assumed, and, in fact, could increase the risk of breast cancer, blood clotting and stroke. Controversy remains over which women are best candidates for HRT and when treatment should begin. LESS
Sex and the transmission of infectious diseaseThe history of sexually transmitted diseases is ancient (the global migration of syphilis from New World to Old World being just one of many chapters), but no sexually transmitted disease has had a greater impact than AIDS, caused by the human immunodeficiency virus (HIV). The scientific campaign to understand HIV and prevent or treat AIDS is one of the most compelling research stories in modern medicine. READ MORE
When HIV first emerged as a health crisis in the 1980s, there were no way to test the blood of individuals who might have been exposed to the virus, which raised widespread concern over transmission of the virus, as well as the safety of the donated blood supply. While HIV testing seemed essential for slowing the spread of AIDS, it couldn’t offer anything for infected individuals, since was there no effective treatment yet available.
Developing diagnostic blood tests for HIV was a major milestone in public health and the research that accomplished this goal will find many other applications in medical science. Detection of the virus relied on the innovative application of medical technologies to measure pathogens (or the production of antibodies they triggered) at extraordinarily low levels.
Today, testing is routinely encouraged for anyone at risk. Testing for pregnant women, in particular, is especially important because HIV-positive mothers can pass HIV on to their babies during pregnancy or delivery or through breast-feeding. Taking anti-retroviral medication during pregnancy and delivery greatly reduces the risk that you'll pass HIV on to your baby.
A deeper understanding of viruses is being applied to many other diseases, including the sexually transmitted human papillomavirus (HPV). The presence of this virus can now be detected from cells taken from a woman’s cervix. It is an innovative and important test, because infection with some types of HPV can lead to the development of cervical cancer, which is the fifth most deadly cancer in women. Unraveling the mysteries of HPV and its link to cancer has allowed made possible a vaccine, which public health experts believe could reduce worldwide cervical cancer deaths by two thirds. LESS