the hemp plant cannabis sativa. The pharmacologically active ingredient in marijuana is tetra-hydro-cannabinol (THC). Marijuana is used to heighten perception, affect mood, and relax. Many people think marijuana is harmless, but it is not. Signs of marijuana use include red eyes, lethargy, and uncoordinated body movements. The long-term effects may include decrease in motivation and harmful effects on the brain, heart, lungs, and reproductive system. People who smoke marijuana are also at increased risk of developing cancer of the head and neck. A pharmaceutical product, Marinol, that contains synthetic THC, is available as a prescription medication. It comes in the form of a pill (eliminating the harmful and cancer-causing chemicals present when marijuana is smoked) and is used to relieve the nausea and vomiting associated with chemotherapy for cancer patients and to treat loss of appetite in AIDS patients.
- Mark of Cain
The mark that God set upon Cain, the eldest son of Adam. According to the Book of Genesis in the Bible, God rejected Cain’s grain offering while accepting the animal offering of his brother Abel. Out of jealousy, Cain murdered his brother and was compelled by God to wander the earth as “a fugitive and […]
- Marker chromosome
An abnormal chromosome that is distinctive in appearance but not fully identified. A marker chromosome is not necessarily a marker for a specific disease or abnormality, but it can be distinguished under the microscope from all the normal human chromosomes. For example, the fragile X (FRAXA) chromosome was once called the marker X.
- Marker gene
A detectable genetic trait or segment of DNA that can be identified and tracked. A marker gene can serve as a flag for another gene, sometimes called the target gene. A marker gene must be on the same chromosome as the target gene and near enough to it so that the two genes (the marker […]
- Marker, blood
A sign of a disease or condition that can be isolated from a blood sample. For example, the monoclonal antibody D8/17 is a diagnostic sign of pediatric autoimmune disorders associated with streptococcus.
- Marker, tumor
A substance that can be detected in higher-than-normal amounts in the blood, urine, or body tissues of some patients with certain types of cancer. A tumor marker may be made by a tumor itself, or it may be made by the body as a response to the tumor. Tumor marker tests are not used alone […]