Heparin-free hemodialysis allows demonstration of the intradialytic coagulation status not previously possible during standard heparin anticoagulant hemodialysis protocols in patients with end-stage renal disease. No evidence for consumptive coagulopathy was noted in the absence of heparin during hemodialysis with cuprophane hollow fiber dialyzers. Fibrinogen levels, euglobulin lysis time, and platelet counts remained stable throughout 3 hours of heparin-free hemodialysis. Serial thrombin times and platelet aggregation improved during heparin-free hemodialysis. Hemodialyzer volumes and the ultrafiltration coefficient decreased only minimally. The alternate pathway of complement activation associated with hemodialysis blood-membrane interaction is not prevented by heparin-free hemodialysis.

Adult↗

PubMedDate not supplied

Review of pyridoxal phosphate and the transaminases in liver disease.

In vitro supplementation with the active form of vitamin B6, pyridoxal-phosphate (PLP), increases measurements of both serum aminotransferase enzymes, L-aspartate: 2-oxoglutarate amino transferase, EC 2.6.1.1 (AST) and L-alanine: 2-oxoglutarate aminotransferase, EC 2.6.1.2 (ALT). The plasma PLP level in normal individuals clearly relates inversely to the degree of stimulation of serum AST and ALT. PLP added in vitro increases the reference values but does not decrease the biological variability of AST measurements in healthy individuals. Since B6 deficiency is observed in alcoholics, in some significant percentage of hospitalized patients and in apparently healthy people over age 64, these individuals will show PLP stimulation of their serum amino-transferase enzymes. Patients with liver disease show lesser activation with PLP of AST activity but not ALT activity than patients with heart disease (myocardial infarction). AST isoenzyme measurements in the form of a mitochondrial AST/total AST ratio may discriminate alcoholic hepatitis from all other hepatic diseases. In renal dialysis patients including transplant patients, it may be desirable to measure the aminotransferases with added PLP in order to reflect better the cytolytic state of the liver. While unconfirmed studies suggest the combination of PLP activation and AST isoenzyme measurements may aid in the diagnosis of hepatoma, PLP activation per se does not provide clear cut improved diagnostic value of AST and ALT in liver diseases. However, in view of PLP incorporation into the IFCC reference methods for AST and ALT, and the National Reference System for the Clinical Laboratory, it is recommended that PLP be included in all AST and ALT measurements.

Alanine Transaminase↗

PubMedDate not supplied

Measurement of total lactate dehydrogenase activity.

Lactate dehydrogenase (LD: EC 1.1.1.27) is the most important clinically of several dehydrogenases occurring in human serum. Lactate dehydrogenase is cytoplasmic in its cellular location and in any one tissue is composed of one or two of five possible isoenzymes. While many of its clinical applications involve quantification of one or more specific serum isoenzymes, an estimate of total LD is required usually. Lactate dehydrogenase catalyzes the reversible reaction: L-lactate + NAD+ in equilibrium pyruvate + NADH. The bidirectional reaction is monitored spectrophotometrically by measuring either the increase in NADH at 340 nm produced in the lactate-to-pyruvate reaction (L----P) or by the decrease in NADH at 340 nm produced in the pyruvate-to-lactate (P----L) reaction. Kinetic assay systems for the measurement of the reaction system in both directions are comprehensively reviewed as well as the standardization efforts proposed to date.

Enzyme Activation↗

PubMedDate not supplied

Urinary enzyme measurements in the diagnosis of renal disorders.

In view of Mattenheimer's comprehensive review of enzymes in renal disease in this journal only four years ago, major emphasis has been placed at the recent Symposium on Diagnostic Significance of Enzymes and Proteins in Urine held at Kanderstag, Switzerland in March of 1978. The pathophysiology of enzyme release in renal disease is presented, the current status of enzyme measurement reviewed, and the laboratory findings in several main types of renal disease summarized. While the measurement of selected urinary enzymes has been found extremely useful in specific situations, most investigators agree that routine screening is not warranted at this time. Newer developments in the measurement of isoenzyme patterns hold promise of introducing increased diagnostic specificity and appear to be the wave of the future.

Acetylglucosaminidase↗