DISEASES

Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver, and brain. This enzyme mediates reduction of the C4-5 double bond of testosterone. Relative to testosterone, DHT is considerably more potent as an agonist of the androgen receptor (AR). In addition to its role as a natural hormone, DHT has been used as a medication, for instance in the treatment of low testosterone levels in men; for information on DHT as a medication, see androstanolone.

A1C may refer to: Airman First Class, the third enlisted rank in the United States Air Force Glycated hemoglobin (hemoglobin A1c or HbA1c), a surrogate marker for blood glucose levels

Abdominal adhesions are bands of fibrous tissue that can form between abdominal tissues and organs. Normally, internal tissues and organs have slippery surfaces, preventing them from sticking together as the body moves. However, abdominal adhesions cause tissues and organs in the abdominal cavity to stick together.

On-and-off abdominal pain and cramps are some of the most common symptoms of Crohn’s disease and ulcerative colitis. Pain and cramping are particularly common symptoms if you have inflammation in the small intestine, which can occur with Crohn’s disease. However, inflammation anywhere in the digestive tract could cause abdominal pain. You may feel pain around the belly button or on the lower right side of the abdomen. It often occurs 1 to 2 hours after eating, but can occur at any time with no obvious cause. The pain may be so severe that you eat less—or avoid eating—to prevent pain and cramping.

Abdominal obesity, also known as central obesity, occurs when excessive abdominal fat around the stomach and abdomen has built up to the extent that it is likely to have a negative impact on health. There is a strong correlation between central obesity and cardiovascular disease. Abdominal obesity is not confined only to the elderly and obese subjects. Abdominal obesity has been linked to Alzheimer's disease as well as other metabolic and vascular diseases.

Visceral and central abdominal fat and waist circumference show a strong association with type 2 diabetes.

Visceral fat, also known as organ fat or intra-abdominal fat, is located inside the peritoneal cavity, packed in between internal organs and torso, as opposed to subcutaneous fat, which is found underneath the skin, and intramuscular fat, which is found interspersed in skeletal muscle. Visceral fat is composed of several adipose depots including mesenteric, epididymal white adipose tissue (EWAT) and perirenal fat. An excess of visceral fat is known as central obesity, the "pot belly" or "beer belly" effect, in which the abdomen protrudes excessively. This body type is also known as "apple shaped", as opposed to "pear shaped", in which fat is deposited on the hips and buttocks.

Researchers first started to focus on abdominal obesity in the 1980s when they realized it had an important connection to cardiovascular disease, diabetes, and dyslipidemia. Abdominal obesity was more closely related with metabolic dysfunctions connected with cardiovascular disease than was general obesity. In the late 1980s and early 1990s insightful and powerful imaging techniques were discovered that would further help advance the understanding of the health risks associated with body fat accumulation. Techniques such as computed tomography and magnetic resonance imaging made it possible to categorize mass of adipose tissue located at the abdominal level into intra-abdominal fat and subcutaneous fat.

Abnormality (or dysfunctional behavior) is a behavioral characteristic assigned to those with conditions regarded as rare or dysfunctional. Behavior is considered abnormal when it is atypical or out of the ordinary, consists of undesirable behavior, and results in impairment in the individual's functioning. Abnormality is that which is considered deviant from specific societal, cultural and ethical expectations. These expectations are broadly dependent on age, gender, traditional and societal categorizations. The definition of abnormal behavior is an often debated issue in abnormal psychology because of these subjective variables.

Abnormal behavior should not be confused with unusual behavior. Behavior that is out of the ordinary is not necessarily indicative of a mental or psychological disorder. Abnormal behavior, on the other hand, while not a mental disorder in itself, is often indicative of mental and psychological disorders. A psychological disorder is defined as an "ongoing dysfunctional pattern of thought, emotion, and behavior that causes significant distress, and is considered deviant in that person's culture or society". Important to note is that abnormal behavior, as it relates to psychological disorders, would be "ongoing" and a cause of "significant distress". A mental disorder describes a patient who has a medical condition whereby the medical practitioner makes a judgement that the patient is exhibiting abnormal behavior based on the DSM-5 criteria. Thus, simply because a behavior is unusual does not make it abnormal; it is only considered abnormal if it meets these criteria.

An induced abortion may be classified as therapeutic (done in response to a health condition of the women or fetus) or elective (chosen for other reasons).

Approximately 205 million pregnancies occur each year worldwide. Over a third are unintended and about a fifth end in induced abortion. Most abortions result from unintended pregnancies. In the United Kingdom, 1 to 2% of abortions are done due to genetic problems in the fetus. A pregnancy can be intentionally aborted in several ways. The manner selected often depends upon the gestational age of the embryo or fetus, which increases in size as the pregnancy progresses. Specific procedures may also be selected due to legality, regional availability, and doctor or a woman's personal preference.

Reasons for procuring induced abortions are typically characterized as either therapeutic or elective. An abortion is medically referred to as a therapeutic abortion when it is performed to save the life of the pregnant woman; to prevent harm to the woman's physical or mental health; to terminate a pregnancy where indications are that the child will have a significantly increased chance of mortality or morbidity; or to selectively reduce the number of fetuses to lessen health risks associated with multiple pregnancy. An abortion is referred to as an elective or voluntary abortion when it is performed at the request of the woman for non-medical reasons. Confusion sometimes arises over the term "elective" because "elective surgery" generally refers to all scheduled surgery, whether medically necessary or not.

Spontaneous abortion, also known as miscarriage, is the unintentional expulsion of an embryo or fetus before the 24th week of gestation. A pregnancy that ends before 37 weeks of gestation resulting in a live-born infant is known as a "premature birth" or a "preterm birth". When a fetus dies in utero after viability, or during delivery, it is usually termed "stillborn". Premature births and stillbirths are generally not considered to be miscarriages although usage of these terms can sometimes overlap.

Only 30% to 50% of conceptions progress past the first trimester. The vast majority of those that do not progress are lost before the woman is aware of the conception, and many pregnancies are lost before medical practitioners can detect an embryo. Between 15% and 30% of known pregnancies end in clinically apparent miscarriage, depending upon the age and health of the pregnant woman. 80% of these spontaneous abortions happen in the first trimester.

The most common cause of spontaneous abortion during the first trimester is chromosomal abnormalities of the embryo or fetus, accounting for at least 50% of sampled early pregnancy losses. Other causes include vascular disease (such as lupus), diabetes, other hormonal problems, infection, and abnormalities of the uterus. Advancing maternal age and a woman's history of previous spontaneous abortions are the two leading factors associated with a greater risk of spontaneous abortion. A spontaneous abortion can also be caused by accidental trauma; intentional trauma or stress to cause miscarriage is considered induced abortion or feticide.

Acanthamoeba is a genus of amoebae, single-celled eukaryotes commonly recovered from soil, fresh water, and other habitats, and is classified into the eukaryote supergroup Amoebozoa. Acanthamoeba has two evolutive forms, the metabolically active trophozoite and a dormant, stress resistant cyst. Trophozoites are small, usually 15 to 35 μm in length and amoeboid in shape. In nature, Acanthamoeba species are free-living bacterivores, but in certain situations, they can cause infections (acanthamebiasis) in humans and other animals.

The free-living amoebae that cause human infections include Acanthamoeba, Naegleria, Balamuthia mandrillaris, and, rarely, Sappinia. All 4 genera cause serious CNS or ocular infections. Distinct from enteric pathogenic protozoa, they all are usually soil/water commensals, have no human carrier state, involve no insect vector, and cause sporadic disease associated with specific behaviors and exposures.

Acanthamoeba are among the most prevalent environmental protozoa and have been classified by 18s rDNA sequencing into at least 20 genotypes, designated T1-T20. The most common environmental and human pathogens belong to the T4 genotype

Acetaminophen is one of the most common medications found in households. It is used for the treatment of pain and to lower fever.

Over many years, it has been used countless times by many people, and it has proven to be a safe and effective medication. However, if taken in excess amounts (overdose, whether on purpose or by accident), acetaminophen can cause life-threatening illness. Unless otherwise directed by your care provider, the usual maximum recommended dose is 3 grams in 24 hours.

Acetaminophen is the active ingredient in Tylenol. It is also found in many other over-the-counter medications and in prescription drugs. Acetaminophen is in Actifed, Alka-Seltzer Plus, Benadryl, Co-Gesic, Contac, Excedrin, Fioricet, Lortab, Midrin, Norco, Percocet, Robitussin, Sedapap, Sinutab, Sudafed, TheraFlu, Unisom PM Pain, Vick's Nyquil and DayQuil, Vicodin, and Zydone.

Acetaminophen in overdose can seriously damage the liver. If the damage is severe, a liver transplant may be necessary in order to save someone’s life.

Achilles tendinitis, also known as achilles tendinopathy, is when the Achilles tendon, found at the back of the ankle, becomes irritated. The most common symptoms are pain and swelling around the affected tendon. The pain is typically worse at the start of exercise and decreases thereafter. Stiffness of the ankle may also be present. Onset is generally gradual.

It commonly occurs as a result of overuse such as running. Other risk factors include trauma, a lifestyle that includes little exercise, high-heel shoes, rheumatoid arthritis, and medications of the fluoroquinolone or steroid class. Diagnosis is generally based on symptoms and examination.

While stretching and exercises to strengthen the calf are often recommended for prevention, evidence to support these measures is poor. Treatment typically involves rest, ice, non-steroidal antiinflammatory agents (NSAIDs), and physical therapy. A heel lift or orthotics may also be helpful. In those in who symptoms last more than six months despite other treatments, surgery may be considered. Achilles tendinitis is relatively common.

Gastroesophageal reflux disease (GERD), also known as acid reflux, is a long term condition in which stomach contents rise up into the esophagus, resulting in either symptoms or complications. Symptoms include the taste of acid in the back of the mouth, heartburn, bad breath, chest pain, vomiting, breathing problems, and wearing away of the teeth. Complications include esophagitis, esophageal stricture, and Barrett's esophagus.Risk factors include obesity, pregnancy, smoking, hiatal hernia, and taking certain medicines. Medications involved may include antihistamines, calcium channel blockers, antidepressants, and sleeping medications. Acid reflux is due to poor closure of the lower esophageal sphincter, which is at the junction between the stomach and the esophagus. Diagnosis among those who do not improve with simpler measures may involve gastroscopy, upper GI series, esophageal pH monitoring, or esophageal manometry.Treatment options include lifestyle changes; medications; and sometimes surgery for those who do not improve with the first two measures. Lifestyle changes include not lying down for three hours after eating, raising the head of the bed, losing weight, avoiding foods which result in symptoms, and stopping smoking. Medications include antacids, H2 receptor blockers, proton pump inhibitors, and prokinetics.In the Western world, between 10 and 20% of the population is affected by GERD. Occasional gastroesophageal reflux without troublesome symptoms or complications is even more common. The classic symptoms of GERD were first described in 1925, when Friedenwald and Feldman commented on heartburn and its possible relationship to a hiatal hernia. In 1934 gastroenterologist Asher Winkelstein described reflux and attributed the symptoms to stomach acid.

It's common for infants to spit up after a meal. That little spit is called gastroesophogeal reflux or GER. But frequent vomiting associated with discomfort and difficulty feeding or weight loss may be caused by something more serious known as GERD (gastroesophageal reflux disease). Both GER and GERD can cause the upward movement of stomach content, including acid, into the esophagus and sometimes into or out of the mouth. Often times, that vomiting is repetitive. The differences between the two conditions are marked by the severity and by the lasting effects.

Older children also can have GERD

Acid–base imbalance is an abnormality of the human body's normal balance of acids and bases that causes the plasma pH to deviate out of the normal range (7.35 to 7.45). In the fetus, the normal range differs based on which umbilical vessel is sampled (umbilical vein pH is normally 7.25 to 7.45; umbilical artery pH is normally 7.18 to 7.38). It can exist in varying levels of severity, some life-threatening.