Urinary Enzymes

Interest and research in urinary enzymology were incited about three decades ago by reports that urinary enzymes are elevated in diseases of the kidney and urinary tract. Of the more than 40 hydrolases, oxidoreductases, transferases, and lyases identified in human and animal urine, only ten or so are being used as diagnostic indicators. Recognition of the quantitative distribution of enzymes in the various anatomical and functional parts of the nephron and advances in our understanding of the handling of proteins by the kidney have made it possible to associate urinary enzyme activity patterns with physiological and pathophysio logical functions of the nephron. Confidence in the diagnostic value of urinary enzymes is not unanimous among clinicians and among scientists. The main reason for the difference in opinion may well be that the variability in data exceeds the variability one is accustomed to in the diagnostic enzymology of blood plasma enzymes. In contrast to plasma enzymes, which are protected by an "enzyme friendly" milieu, enzymes released into the urine encounter an "enzyme hostile" environ ment: no or little protective protein, variable pH, variable volume, variable metabolite and salt concentrations, variable concentrations of enzyme in hibitors. Through advances in methodology some of these factors can now be controlled; standardization of urine collection periods and preanalytical treat ment are as important as optimization of assay methods.

Klappentext

The book provides a comprehensive uptodate review of thepresent state of knowledge of urinary enzymes. Since itdeals with all the essential questions currently beingdiscussed in connection with urinary enzymes, it will be ofinterest to biochemists, clinical chemists, renalphysiologists, nephrologists and clinicians working on renalproblems.The chapters are grouped into 5 parts, the firstofferingan update of the biochemical and morphologicalfundamentals of the excretionof urinary enzymes, includinga description of the distribution of diagnostically relevantenzymes along the nephron, the mechanisms of enzyme release,and the physiological factors influencing the excretionrate. The chapters in the second part deal with themethodological fundamentals ofthe activity determination ofurinary enzymes (preanalytical treatment, quality assurance,methodical details for the most important enzymes, reviewonreference intervals). The four chapters in the third partreview aspects of urinary enzyme excretion in clinicalmedicine (renal, renal associated, and urological disorders,kidney transplantation, nephrotoxicity, extrarenal diseases)and includes a special chapter on the general background forinterpreting data on urinary enzyme excretion. The fourthpart, consisting of 3 chapters, covers urinary enzymes inanimal experiments (animal models, influence of differentsubstances on urinary enzyme excretion, reference values invarious animals). The book concludes with a review of theposibilities for using renal enzymes as the basis foralternative methods of screening toxic substances.

Inhalt
1 Biochemical, Pathobiochemical, and Morphological Fundamentals of the Excretion of Urinary Enzymes.- 1 Origin of Enzymes in Urine.- 2 Distribution of Diagnostically Relevant Enzymes Along the Nephron.- 3 Mechanisms of Enzyme Release and Causes of Altered Enzyme Excretion.- 4 Enzymuria as an Indicator of Renal Pathomorphology.- 5 Physiological Factors Influencing Enzyme Excretion.- 2 Methodological Fundamentals of the Activity Determination of Urinary Enzymes.- 6 Preanalytical Treatment of Urine.- 7 Quality Assurance.- 8 Methods for Measuring Urinary Enzyme Activities.- 9 Basis of Reference.- 10 Reference Intervals.- 3 Urinary Enzymes in Clinical Medicine.- 11 Clinical Interpretation of Urinary Enzyme Excretion.- 12 Urinary Enzymes in Renal, Renal-Associated and Urological Disorders.- 13 Urinary Enzymes in Kidney Transplantation.- 14 Urinary Enzymes and Nephrotoxicity in Humans.- 15 Extrarenal Diseases.- 4 Urinary Enzymes in Animal Experiments.- 16 Animal Models.- 17 Reference Values.- 18 Influence of Different Substances on Urinary Enzyme Excretion.- 5 Nephrotoxicity.- 19 Renal Enzymes as the Basis for Alternative Methods of Safety Screening In Vitro and Understanding the Mechanism of Nephrotoxicity.