Metabolism, basic principles

Schuette CG et al The glycosphingolipidoses—from disease to basic principles of metabolism. Biol Chem 1999 380 759-... 

Camici P, Ferrannini E, Opie LH. Myocardial metabolism in ischemic heart disease basic principles and application to imaging by positron emission tomography. Prog Cardiovasc Dis 1989 32 217-238... 

Sokoloff L, Smith CB (1983) Basic principles underlying radioisotopic methods for assay of biochemical processes in vivo. In Greitz T, Ingvar DH, Widen L, eds. The Metabolism of the Human Brain Studied with Positron Emission Tomography. New York, USA Raven Press pp. 123-148. 

The last decade has seen an explosion of interest in Mn transport and regulation. While this remains poorly characterized in comparison with the much better studied areas of Fe and Cu homeostasis (see Metallochaperones Metal Ion Homeostasis), the basic principles of Mn metabolism are beginning to be worked out. In yeast, there are at least two independent systems for importing Mn into the cell. The high-affinity transporter, operative under... 

In this article, we will focus mainly on the mechanisms of iron and zinc regulation, because regulation of these two metals illustrates many basic principles. We will also reference reviews that address regulation of copper and manganese metabolism, but regulation of these metals will not be discussed in depth here, in part because they will be discussed elsewhere. 

This book is devoted to basic principles of pharmacology and lias good chapters on drug metabolism and pharmacogenetics. 

Holmsen H. Platelet secretion and energy metabolism. In Colman RW, Hirsh J, Marder VJ, Salanan EW eds. Hemostasis and thrombosis. Basic principles and clinical practice. Philadel hia J.B. Lippincott 1994 524-45. 

Metabolic rates are not the only rates that can be manipulated. The rates of all chemical reactions, from the most explosive to the most sluggish, are described by a set of basic principles, and it is these that we will look at next. 

Nutrition The patient s diet should comply with the basic principles of physiological nutrition. It is recommended to take three main and two minor meals per day. Foodstuffs causing flatulence and containing poorly digestible fats (e. g. lard) should be avoided. It is important to consider the influence of glucocorticoids on appetite as well as their metabolic side effects (e. g. restriction of sodium chloride, loss of potassium). 

Klebanolf SJ. 1988. Phagocytic cells products of oxygen metabolism. In Inflammation Basic Principles and Clinical Correlates, ed. JI Gallin, IM Goldstein, R Snyderman, pp. 391 444. New York Raven... 

FBA is attractive as a predictive tool. That is, once the model is constructed, one can predict the metabolic behavior under a number of different conditions. The basic principle underlying FBA is the steady-state conservation of mass, energy, and redox potential. A dynamic mass balance can be written arormd each metabolite (A,) within a metabolic network. Fig. 4 shows a hypothetical network with the fluxes (V) affecting a metabolite (A,). The dynamic mass balance for A,- is ... 

Caldwell, J., Gardner, I., and Swales, N. 1095. An intruducUon lodruii disposition The basic principles of absorption, distribution, metabolism. and excretion. Toxicol. Pathol. 23 102-114. 

Answer E. Back to basic principles. Zero-order elimination means that plasma levels of a drug decrease linearly with time. This occurs with ASA at toxic doses, with phenytoin at high therapeutic doses, and with ethanol at all doses. Enzymes that metabolize ASA are saturated at high plasma levels —> constant rate of metabolism = zero-order kinetics. Remember that application of the Henderson-Hasselbalch principle can be important in drug overdose situations. In the case of aspirin, a weak acid, urinary alkalinization favors ionization of the drug —>4 tubular reabsorption —>T renal elimination. 

In the case of remifentanil it was also proved that, as predicted by the basic principles used in soft drug design, the possibility of drug interactions could be minimized by building metabolic considerations into the structure. Clearance, volume of distribution, and terminal half-life data indicated that coadministration of esmolol has no significant (P < 0.05) effect on the pharmacokinetics (or pharmacodynamics) of remifentanil in rats, despite both drugs being metabolized by nonspecific esterases (99,100). 

This reaction is a particularly clear example of electron transfer. It will be useful to keep these basic principles in mind when we examine the flow of electrons in the more complex redox reactions of aerobic metabolism. In many of the biological redox reactions we will encounter, the oxidation state of a carbon atom changes. Figure 15.2 shows the changes that occur as carbon in its most reduced form (an alkane) becomes oxidized to an alcohol, an aldehyde, a carboxylic acid, and ultimately carbon dioxide. Each of these oxidations requires the loss of two electrons. 

The basic principles of drug metabolism may inform a wide variety of clinical decisions regarding pharmacotherapy. For example, a... 

Hoffman, R. et al.. Disorders of iron metabolism Iron deficiency and overload, in Hematology Basic Principles and Practice, 3rd edn, Churchill Livingstone, Harcourt Brace Co, New York, 2000, Chap. 26. 

---