Category: O

An antiviral drug. Oseltamivir (Tamiflu] is used to treat infections caused by viruses, particularly those caused by influenza A and influenza B viruses. Oseltamivir reduces the severity of flu symptoms, including fever, headache, cough, and sore throat, in a single day. It should be taken within 2 days of the start of flu symptoms to…

The medical specialty that studies, diagnoses, and treats disorders of the musculoskeletal system, including the bones, joints, muscles of the arms and legs, ligaments, tendons, nerves, the spine, and associated structures. Orthopedic surgery uses medical, surgical, and physical means to study and treat problems in the form and function of the body’s bones, muscles, and…

Fixed or removable devices fitted on the teeth by an orthodontist to improve the position of the teeth in the jaw. Orthodontic appliances are generally made of metal and plastic; some may be gold-plated. Ceramic appliances are made of a tooth-colored material that is less noticeable than standard metallic braces; they are durable and may…

A term formerly used to describe mental illnesses due to a non-psychiatric medical condition rather than a psychological cause. It is now known that all mental illnesses have at least some biological basis. Organic brain disorder is divided into three types of mental illness. The first is delirium—a state of mental confusion that develops over…

An injunction or court order issued to prohibit violent or threatening acts against a specific individual. An order of protection may be issued by a judge in cases when one person has a history of having threatened, harassed, or attacked another person. Orders of protection  are often sought by victims of domestic or family violence…

Swelling of the region where the optic nerve joins the retina (the thin light-sensitive area in the back of the eye). Because of swelling, the optic disc looks “angry” (inflamed and swollen), its margins become blurred and hard to distinguish, and the small cup in the center of the disc decreases in size. Optic disc…

An antiemetic; an antinausea drug. Ondansetron hydrochloride (Zofran) is used to treat or prevent nausea and vomiting that may occur following chemotherapy or radiation therapy for a person with cancer, or following surgery.  

A rare type of brain tumor. Oligodendrogliomas grow very slowly and primarily affect young or middle-aged adults. Some of these tumors are cancerous, though most are benign. They can be present for years without being detected and diagnosed, and survival for many years after diagnosis is possible. Symptoms and treatment are the same as for…

A measure of tumor sensitivity to the presence or absence of oxygen equal to the ratio of radiation dose required to produce a given effect with no oxygen present to the dose required to produce the same effect in one atmosphere of air. This is an important effect in radiation therapy where tumor cells may…

X-ray generators for radiation therapy operating in the voltage range of 100-350 keV are described as orthovoltage equipment. They are of limited use in radiotherapy now that megavoltage equipment is readily available. The median voltage used in x-ray therapy, approx. 250 kV.