Medical Consultations

Zygotic lethal gene

2011-08-22T14:37:00.000-07:00

Zygotic lethal gene: A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene scotches prenatal development at its earliest point.

A zygotic lethal gene is a mutated (changed) version of a normal gene essential to the survival of the zygote. The extent of the mutation can range from a change in a single base in the DNA to deletion (loss) of the entire gene.

Zygote intrafallopian transfer (ZIFT)

2011-08-22T14:36:00.002-07:00

Zygote intrafallopian transfer (ZIFT): A technique in which a woman's egg is fertilized outside the body, then implanted in one of her fallopian tubes. This technique is one of the methods used to overcome infertility, the inability of couples to produce offspring on their own.

First, the egg and the male sperm needed to fertilize it are harvested. Then the egg and the sperm are united in a petri dish, a multi-purpose glass or plastic container with a lid. If all goes well, the sperm fertilizes the egg, and the physicians then implant it in a fallopian tube. From there, nature takes its course, and the egg eventually is deposited by the fallopian tube into the uterus (womb) for development.

A zygote is the combined cell resulting from the union of sperm and egg. A zygote develops into an embryo. An embryo, a mass of cells with no recognizable human features, begins formation of a human body. After about seven or eight weeks, the embryo exhibits recognizable features such as a mouth and ears. At this stage, the developing human becomes known as a fetus. The word "zygote" is derived from the Greek word "zygon" (yoke).

The term "intrafallopian" means "inside the fallopian tubes." ("Intra," a Latin word, means "within" or "inside.") Thus, the term "zygote intrafallopian transfer" refers to the transfer of a zygote into a fallopian tube.

Zygote

2011-08-22T14:36:00.001-07:00

Zygote: The cell formed by the union of a male sex cell (a sperm) and a female sex cell (an ovum). The zygote develops into the embryo following the instruction encoded in its genetic material, the DNA.

The unification of a sperm and an ovum to form a zygote constitutes fertilization.

Zygomycosis

2011-08-22T14:35:00.000-07:00

Zygomycosis: A dangerous infection caused by a water-borne fungus. Zygomycosis is seen most often in patients who are already ill with diseases that cause wasting, such as AIDS or poorly controlled diabetes. If unchecked, the fungal infection can spread to the lungs and other organs, the blood, the eyes, and the brain. Treatment is two-fold: controlling the underlying condition, and attacking the infection with anti-fungal medications.

Zygomatic bone

2011-08-22T14:34:00.002-07:00

Zygomatic bone: The part of the temporal bone of the skull that forms the prominence of the cheek.

The zygomatic bone is also known as the zygomatic arch, the zygoma, the malar bone, the cheek bone and the yoke bone.

The word "zygomatic" comes from the Greek "zygon" meaning a yoke or crossbar by which two draft animals such as oxen could be hitched to a plow or wagon.

Zygomatic arch

2011-08-22T14:34:00.001-07:00

Zygomatic arch: The part of the temporal bone of the skull that forms the prominence of the cheek.

The zygomatic arch is also known as the zygomatic bone, the zygoma, the malar bone, the cheek bone and the yoke bone.

The word "zygomatic" comes from the Greek "zygon" meaning a yoke or crossbar by which two draft animals such as oxen could be hitched to a plow or wagon.

Zygoma

2011-08-22T14:33:00.000-07:00

Zygoma: The part of the temporal bone of the skull that forms the prominence of the cheek.

The zygoma is also known as the zygomatic bone or arch, the malar bone, the cheek bone and the yoke bone.

The word "zygomatic" comes from the Greek "zygon" meaning a yoke or crossbar by which two draft animals such as oxen could be hitched to a plow or wagon.

Zoophobia

2011-08-22T14:32:00.002-07:00

Zoophobia: An abnormal and persistent fear of animals.

A phobia is an unreasonable fear that can cause avoidance and panic. Phobias are a relatively common type of anxiety disorder. Phobias can be treated with cognitive behavioral therapy using exposure and fear reduction techniques. In many cases, anti-anxiety or anti-depressant medication proves helpful, especially during the early stages of therapy.

Zoophobia is a term that encompasses fears of specific types of animals such as of spiders (arachnophobia), birds (ornithophobia), bees (apiphobia), etc. It is a zoo-ful of beastly phobias.

Zoophilia

2011-08-22T14:32:00.001-07:00

Zoophilia: A sexual disorder involving an erotic attraction to animals or an abnormal desire to have sexual contact with animals. Zoophilia is one form of paraphilia (deviant sexual behavior).

Zooparasite

2011-08-22T14:31:00.000-07:00

Zooparasite: A living parasite, such as a worm or protozoa.

Zoonotic transfer

2011-08-22T14:30:00.002-07:00

Zoonotic transfer: The transmission of a disease from an animal host to a human. Infections transmitted from their animal host of origin to people may have a very severe impact. Hantavirus is an example. See also: Zoonosis; Zoonotic; Zoonotic disease.

Zoonotic disease

2011-08-22T14:30:00.001-07:00

Zoonotic disease: Any disease that is spread from animals to people. There are many known zoonotic diseases, some of them very familiar such as Lyme disease and malaria. Less familiar zoonotic diseases (beginning with the letters "a" and "b") include alveolar hydatid disease (echinococcosis), ancylostoma infection (hookworm), ascariasis (intestinal roundworm infection), babesiosis (babesia infection), and baylisascaris infection (raccoon roundworm).

Zoonotic

2011-08-22T14:29:00.000-07:00

Zoonotic: Pertaining to a zoonosis: a disease that can be transmitted from animals to people or, more specifically, a disease that normally exists in animals but that can infect humans. There are multitudes of zoonotic diseases.

Some examples include:

anthrax
ascariasis
brucellosis
plague
echinococcosis
Lassa fever
listeriosis
Lyme disease
monkeypox
psittacosis
rabies
salmonellosis
trichinosis
toxoplasmosis
typhus and
West Nile fever
Zoonoses may appear suddenly and be relatively virulent, as illustrated by HIV which ignited the AIDS epidemic and the coronavirus responsible for the outbreak of SARS.

Zoonosis

2011-08-22T14:28:00.002-07:00

Zoonosis: An infectious disease in animals that can be transmitted to people. The natural reservoir for the infectious agent is a animal.

Examples of zoonoses include rabies (a viral disease that can be transmitted to humans through an infected animal's bite) and psittacosis (a chlamydial infection resembling influenza that is spread to humans by the droppings of infected birds).

Anthrax is a zoonosis. It normally affects animals, especially ruminants (such as goats, cattle, sheep, and horses), but can be transmitted to humans by contact with infected animals or their products or by biological warfare.

Zone Diet

2011-08-22T14:28:00.001-07:00

Zone diet: The Zone diet is a weight loss plan based upon the idea that the right ratio of carbohydrates to proteins and fats can control levels of insulin in the bloodstream. Too much of the hormone, according to the diet's developer Barry Sears, PhD, can increase fat storage and inflammation in the body.

In his book The Zone, Sears writes that metabolism can be best regulated with a diet of 40% carbohydrates, 30% protein, and 30% fat. This idea is now widely known as the 40-30-30 plan. The diet does not prohibit any foods, but severely restricts those high in fat and carbohydrates. Fruits and vegetables are the preferred source of carbohydrates in the Zone diet. Protein is limited to low-fat portions that are no bigger and no thicker than the palm of the hand. Monounsaturated fats such as olive oil, canola oil, almonds, macadamia nuts, and avocados are recommended.

The American Heart Association (AHA) classifies the Zone as a high-protein diet and has issued an official recommendation warning against such programs. The AHA statement says high-protein diets have not been proven effective for long-term weight loss and could actually be hazardous to health because they restrict intake of essential vitamins and minerals . On the other hand, the American Dietetic Association (ADA) rates The Zone more moderately and suggests that it is closer to dieticians' recommendations than some other high-protein diets.

Zona pellucida

2011-08-22T14:27:00.000-07:00

Zona pellucida: The strong membrane that forms around an ovum as it develops in the ovary. The membrane remains in place during the egg's travels through the Fallopian tube. To fertilize the egg, a sperm must penetrate the thinning zona pellucida. If fertilization takes place, the membrane disappears to permit implantation in the uterus.

Zona

2011-08-22T14:26:00.002-07:00

Zona: 1. A synonym for shingles. 2. Any zone or encircling area. 3. Any area with a specific boundary.

Zona, Latin for a girdle, is a synonym for shingles because it can appear to girdle part of the body.

Zomig

2011-08-22T14:26:00.001-07:00

Zomig: Brand name for zolmitriptan, a triptan drug for the treatment of migraine.

Zolpidem

2011-08-22T14:25:00.000-07:00

Zolpidem: Brand name: Ambien. A sedative hypnotic drug in a class closely related the benzodiazepines, affecting the central nervous system, used as a sleep drug. For more information, see: zolpidem.

Zolmitriptan

2011-08-22T14:24:00.000-07:00

Zolmitriptan: A triptan drug for the treatment of migraine. Marketed under the brand name Zomig

Zollinger-Ellison syndrome

2011-08-22T14:22:00.001-07:00

Zollinger-Ellison syndrome: A rare disorder caused by a tumor called a gastrinoma, most often occurring in the pancreas. The tumor secretes the hormone gastrin, which causes increased production of gastric acid leading to severe recurrent ulcers of the esophagus, stomach, and the upper portions of the small intestine (the duodenum and jejunum).

Gastrinomas resulting in the Zollinger-Ellison syndrome are not limited to the pancreas but may also occur in the stomach, duodenum, spleen and lymph nodes.

The treatment of the Zollinger-Ellison syndrome includes the use of H2 antagonists (for example cimetidine [brand name: Tagamet] and ranitidine [Zantac]) and the proton pump inhibitors (for example, lansoprazole [Prevacid] and omeprazole [Prilosec]). The H2 antagonists block the action of histamine on stomach cells, thus reducing stomach acid production. The proton pump inhibitors also block the production of acid by the stomach cells. Surgical removal of the tumor is curative in about 25% of cases.

The syndrome is named for two American surgeons Robert M. Zollinger (1903-1992) and Edwin H. Ellison (1918-1970).

Zollinger-Ellison syndrome

2011-08-22T14:22:00.000-07:00

Zoll, Paul M.

2011-08-22T14:21:00.000-07:00

Zoll, Paul M.: American cardiologist (1911-1999) and pioneer in the development of the cardiac monitor, pacemaker and defibrillator.

Zinc oxide

2011-08-22T14:19:00.000-07:00

Zinc oxide: A form of zinc that has antispasmodic qualities.

Zinc ointment

2011-08-22T14:17:00.000-07:00

Zinc ointment: A topical preparation containing zinc that is applied to protect the skin from irritation or sunburn. Zinc ointment is often the basis for commercial preparations for preventing diaper rash. It should not be used on skin that is already broken or irritated, however.