multidrug resistance

resistance /re·sis·tance/ (re-zis´tans)

1. opposition, or counteracting force.

2. the natural ability of an organism to resist microorganisms or toxins produced in disease.

3. the opposition to the flow of electrical current between two points of a circuit. Symbol R or .

4. in psychiatry, conscious or unconscious defenses that prevent material in the unconscious from coming into awareness.

---

airway resistance  the opposition of the tracheobronchial tree to air flow. Symbols RA, RAW.

androgen resistance  resistance of target organs to the action of androgens; the result is any of a spectrum of defects. In mild to incomplete types the person may have a definite male phenotype but infertility, or may have ambiguous genitalia. In the complete type the person has a female phenotype but XY chromosomes.

drug resistance  the ability of a microorganism to withstand the effects of a drug that are lethal to most members of its species.

electrical resistance  resistance (3).

multidrug resistance , multiple drug resistance in some malignant cell lines, resistance to many structurally unrelated chemotherapy agents in cells that have developed natural resistance to a single cytotoxic compound.

vascular resistance  the opposition to blood flow in a vascular bed.

---

multidrug resistance,

1 the resistance of tumor cells to more than one chemotherapeutic agent. Resistance may be aided by a P-glycoprotein transmembrane pump that lowers the concentration of drugs in the cell.

2 the resistance of bacteria, especially Mycobacterium tuberculosis, against more than two of the antibiotics that were once effective.

---

multidrug resistance,

n the adaptation of tumor cells or infectious agents to resist chemotherapeutic agents.