Human Biochemistry Volume 1 - Murray R. 1993

Biochemistry and Medicine
Biochemistry and Disease

All diseases manifest as alterations in molecular properties and disruptions in Chemical Reactions and biological processes. The primary factors contributing to The Development of diseases in humans and animals are summarized in Table 1.1. Each of these factors affects one or more key chemical reactions or alters the Structure and properties of functionally vital molecules.

THE CONTRIBUTION OF biochemical research to the Diagnosis and Treatment of diseases can be outlined as follows.

Class="center">Table 1.1. Major factors leading to the development of disease. All of these factors affect various biochemical processes occurring within The Cell or the whole Organism¹⁾

¹⁾ Modified and adapted from Robbins S. L., Cotram R. S., Kumar V.: The Pathologic Basis of Disease, 3rd ed. Saunders, 1984, with the kind permission of the authors.

These investigations make it possible to: 1) identify the underlying cause of a disease; 2) propose rational and effective treatments; 3) develop mass-screening techniques for early diagnosis; 4) monitor the progression of a disease; and 5) evaluate the efficacy of treatment. The Appendix outlines the most important biochemical assays used in diagnosing various disorders. It will be helpful to refer to this Appendix whenever biochemical Diagnostics of specific diseases (such as myocardial infarction or acute pancreatitis) are discussed.

The potential of biochemistry in preventing and treating diseases is briefly illustrated by three Examples; we will examine several more examples later in this chapter.

1. It is well established that maintaining human health requires the intake of specific complex Organic compounds known as Vitamins.

Within the body, vitamins are converted into more complex molecules (Coenzymes) that play a pivotal role in numerous cellular reactions. A dietary deficiency of any of these vitamins can lead to various pathologies, such as scurvy resulting from Vitamin C Deficiency or Rickets caused by Vitamin D deficiency. Elucidating the crucial role of VITAMINS AND THEIR biologically active derivatives has been one of the primary objectives pursued by biochemists and nutritionists since the beginning of this century.

2. Phenylketonuria (PKU), a pathological condition that leads to severe mental retardation if left untreated, has had its biochemical basis understood for about 30 years. The disease is caused by a deficiency or complete absence of the enzyme that catalyzes The conversion of The amino acid phenylalanine into another amino acid, Tyrosine. This enzymatic defect results in an accumulation of excess phenylalanine and certain of its metabolites—particularly ketones—in Tissues, which adversely affects the Development of the Central Nervous system. Once the BIOCHEMICAL FOUNDATIONS OF PKU were uncovered, a rational treatment strategy was devised: affected children are placed on a phenylalanine-restricted diet. Mass Newborn Screening for PKU allows treatment to be initiated promptly when necessary.

3. Cystic fibrosis is an inherited disorder affecting exocrine glands, particularly the Sweat Glands, with an as-yet-unknown Etiology. It is one of the most prevalent genetic diseases in North America and is characterized by abnormally viscous secretions that obstruct the secretory ducts of the Pancreas and bronchioles. Affected individuals most often succumb at an early age to pulmonary infections. Because the Molecular Basis of the disease remains obscure, only symptomatic treatment is currently available. Nevertheless, it is hoped that in the near future, Recombinant DNA technology will help elucidate the molecular Nature of the disorder, thereby paving the way for more effective therapies.