The Kanji Foundry Press - Z
 

  

Zafirlukast: a leukotriene receptor antagonist used clinically in the prevention of asthma and to treat chronic asthma. It inhibits the effects of cysteinyl leukotrienes in the airways.

Zalcitabine: a nucleoside analogue and reverse transcriptase inhibitor used clinically in the treatment of HIV infections in combination with other antivirals.

Zaragozic acids: also known as squalestatins, a group of potent cholesterol biosynthesis inhibitors which act as presqualene pyrophosphate mimics and inhibit squalene synthase. Some zaragozic acids also exhibit antifungal and antitumour activities.

ZD7114: a selective β3- adrenoceptor agonist used as a pharmacological tool.

Zeodary sesquiterpene: sesquiterpenes derived from zedoary (Curcuma zedoaria), a plant related to turmeric and native to India. Zeodary rhizome has been used in traditional Chinese medicine for a long time as it has stomachic (an agent which stimulates the actions of the stomach) and anti-inflammatory actions. It contains sesquiterpenes such as dehydrocurdione which may have Ca2+ channel blocker-like effects.

Zero-order kinetics: also known as rate-limited, dose-dependent and saturation kinetics, the simplest kinetic describing the absorption and elimination of drug from the body or the rate of substrate consumption by an enzyme. The rate at which absorption, elimination or catalysis occurs is not dependent on the amount of substance being dealt with. The equation (for drug elimination) is dc/dt = - ko (where dc is the change in drug concentration, dt is the change in time and ko is the elimination rate constant with units of amount of drug per time) and describes zero-order kinetics.

Zidovudine: also known as azidothymidine and AZT, a pyrimidine nucleoside analogue, reverse transcriptase inhibitor and antiviral compound (3'-azido-3'-deoxythymidine). It also exhibits antimetabolite and antineoplastic activity in vitro. It is used clinically in the treatment of AIDS and AIDS-related complex in combination with other antiviral drugs. It is phosphorylated intracellularly to its triphosphate form and competes with other cellular triphosphates which are essential in the formation of DNA by viral reverse transcriptase. Its incorporation into replicating DNA chain causes termination of DNA synthesis. Although mammalian alpha DNA polymerase is relatively resistant to this effect, mitochondrial gamma DNA polymerase is quite sensitive to its actions and this gives rise to its side effects, ie anaemia and neutropenia. Decreased conversion of zidovudine to its triphosphate and viral mutations may account for resistance to this antiviral.

Zileutin: an orally active 5-lipoxygenase inhibitor used clinically to treat asthma in adults as it inhibits leukotriene formation.

ZM241385: a potent and highly selective A2A adenosine receptor antagonist.

Zucker rat: a strain of rat reported originally by Lois and Theodore Zucker as a genetic mutation in the early 1960s. This mutation resulted in juvenile-onset obesity, increased food intake, decreased energy expenditure and insulin resistance. This mutation was called fatty (fa). The gene responsible for this mutation (fatty gene) is passed on to successive generations by an autosomal recessive inheritance. Zucker fatty rats are phenotypically obese, exhibit hyperlipidemia, hyperinsulinaemia and decreased glucose tolerance. Consequently, they have become established models for the study of obesity.

Zymogens: inactive precursors of enzymes which are usually proteolytic. They include the precursors of the closely related digestive endopeptidases trypsin (tryspsinogen), chymotrypsin (chymotrypsinogen), carboxypeptidases A and B (procarboxypeptidases A and B) and elastase (proelastase) which are synthesized in the pancreas and the blood coagulation enzyme plasmin (plasminogen). Trypsinogen, chymotrypsinogen and proelastase are secreted into the small intestine where they are activated by proteolytic cleavage to their active form.