Johannes Aufenanger

Pancreatic phospholipase A2 activity in acute pancreatitis: a prognostic marker for early identification of patients at risk

Abstract Remarkably elevated levels of phospholipase A2 (PLA2) are measurable in human blood samples in cases of acute pancreatitis. The source of the enzyme was first thought to be exclusively the pancreas, but now it is generally accepted that two isoenzymes – the pancreatic PLA2, group I, and the extrapancreatic PLA2, group II – contribute to the raised activity. In contrast to the group II-PLA2, the pancreatic PLA2 is heat-resistant for 1 hour at 60 °C. The catalytically inactive proenzyme of the pancreatic PLA2 can be activated by trypsin. The aim of our study was to evaluate the diagnostic value of PLA2 isoenzyme activity measurements to identify patients with severe complications in acute pancreatitis. Blood samples from patients suffering from acute pancreatitis were analyzed for catalytically active pancreatic PLA2 on day 1 and 2 of hospitalization with a modified radiometric Escherichia coli-based PLA2 assay. In 10 of 41 patients clearly elevated values of catalytically active, heat-resistant pancreatic PLA2 (7.2 to 81.2 U/l) were observed. This group of patients was characterized by severe complications (necrotizing pancreatitis, shock, sepsis, respiratory problems) of which two patients subsequently died. Patients with low or undetectable activity (<7 U/l) of pancreatic PLA2 recovered rapidly. According to these results the presence of catalytically active pancreatic PLA2 in serum is associated with severe complications of acute pancreatitis. In contrast to total serum-PLA2, the catalytic concentration of pancreatic PLA2 can serve as a prognostic marker in acute pancreatitis.

Screening for subclinical inflammation in ejaculates

OBJECTIVE To determine the clinical significance of albumin determination in ejaculates by means of an easy office test to screen semen samples for subclinical infection-inflammation. PATIENTS One hundred fifty-nine randomly chosen males of couples with longstanding infertility (median duration of infertility 4 years (range 1 to 19 years) without clinical signs or symptoms of genital tract infection. SETTING Outpatient Infertility Clinic of the University of Heidelberg, Germany. MAIN OUTCOME MEASURES Screening of ejaculates for subclinical infection-inflammation by means of a ready-to-use kit for semiquantitative detection of albumin in addition to determination of leukocytes rates by means of monoclonal antibodies for differentiation of round cells and measurement of granulocyte elastase concentration in semen samples. Evaluation of sperm quality by means of standard sperm analysis including determination of local antisperm antibodies with the mixed antiglobulin reaction, evaluation of sperm functional capacity in vitro with the standardized sperm-cervical mucus (CM) penetration test, and semen cultures. All tests were performed from aliquots of the same ejaculates. RESULTS Screening of semen samples for elevated albumin with the modified paper strips proved to be very easy, quick, and suitable for routine use. Positive results were not related markedly to medical history and outcome of clinical examination as well as to standard parameters of sperm analysis and were not influenced by local antisperm antibodies of the immunoglobulin (Ig)G and/or IgA class and microbial colonization. However, albumin-positive semen samples were significantly less frequent in case of very good outcome of the sperm-CM penetration test. A significant relationship was found with high rates of leukocytes of the round cells in semen samples (total range 0% to 96%) and the concentration of granulocyte elastase (total range 1 to 880 micrograms/L). CONCLUSIONS The results of this prospective study suggest that the determination of albumin in semen samples with ready-to-use test kits might be a valuable additional marker for subclinical infection-inflammation of the male genital tract and therefore suitable for screening during infertility investigation.

Benefits and limitations of laboratory diagnostic pathways

Abstract Diagnostic pathways are an essential subset of clinical pathways and a logical consequence of DRG-based reimbursement. They combine the principle of stepwise reflex and reflective testing with a management concept that helps to fulfill medical needs with organizational and economic efficacy. The two most common formats describing diagnostic pathways are graphical decision trees on paper and “if…then…else” rules on computers. From a laboratory point of view, diagnostic pathways represent “smart” test profiles, which – in contrast to conventional (inflexible) profiles – are not necessarily worked off completely, but just to a point, where a diagnostic decision can be made. This improves the cost-effectiveness of laboratory testing, while making sure that no essential tests are missed. The paper describes benefits and limitations of diagnostic pathways from a medical, organizational, and economic point of view. Their major advantage is also their major drawback, since they make the diagnostic process on the one hand extremely straight-forward and transparent, while on the other hand oversimplifying the underlying medical decision principles. This may provoke the abuse of their primarily medical intentions for mere economic purposes.

Recommendations for the frequency of ordering laboratory testing

Abstract Laboratory testing is crucial for the successful medical treatment of many patients. Laboratory tests should neither be ordered too infrequently nor too frequently (in the form of repeat testing). These recommendations summarize the intervals for repeat testing based on studies, pathophysiology and consensus, in regard to both the time intervals between two tests and the additional criteria for the repeat testing. These recommendations are complemented by general principles for the indication and testing frequency of laboratory testing.

Phospholipase A activity in Pseudomonas aeruginosa

Our study describes the production, purification and properties of an enzyme from Pseudomonas aeruginosa displaying the properties of phospholipase A. Maximal amounts of enzyme could be detected in the culture supernatant when the bacterium was grown for 3 to 5 days at 37 degrees C in stirred flask cultures containing brain heart infusion. The enzyme was purified by polyethylenimine precipitation and ammonium sulfate precipitation followed by gel filtration. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the enzyme preparation exhibited two bands with molecular weights of 13.5 and 60 kD, respectively. Correspondingly, two peaks of the same molecular weight could be demonstrated by high performance size exclusion chromatography. The activity toward the sn-2 ester binding of phospholipids was characterized and found to be highest towards phosphatidylcholine. Enzymatic activity was not influenced by the addition of calcium or EDTA while magnesium and strontium caused a decrease of activity. The lyophilized enzyme was found to be stable when stored at -70 degrees C and most active at pH 8.0.

Chancen und Risiken von e-Health in der Labormedizin

Zusammenfassung Aus dem Lifestyle- und Wellnessbereich werden den Kunden vielfältige Apps angeboten, die die Kundendaten ansprechend digital präsentieren. Auch der politische Wille fordert die Digitalisierung in der Medizin mit dem sog. „E-Health-Gesetz“. In der nationalen elektronischen Patientenakte sollen dazu auch Laborbefunde gespeichert werden. Dafür notwendig ist allerdings eine ausreichende Harmonisierung von Prä-Präanalytik (Terminologie, Testprofile, Testungsintervalle), Präanalytik (Abnahmezeiten, Patientenvorbereitung, Probentransport und Probenlagerung), Analytik (Probenqualität, Methode, Kalibration, Qualitätssicherung) bis hin zur Postanalytik (Einheiten, Datenformate, Referenzintervalle, Entscheidungswerte). Diese Harmonisierung kann aufgrund der vielen verschiedenen Laboruntersuchungen und parameterspezifischen Besonderheiten trotz weitreichender nationaler und internationaler Aktivitäten noch nicht als abgeschlossen gelten. Andere Herausforderungen elektronischer Patientenakten liegen bei der Datensicherheit (d.h. der Integrität der Laborbefunde) und dem Datenschutz unter Berücksichtigung der informationellen Selbstbestimmung der Patienten und weiterer Gesetze wie dem Gendiagnostikgesetz (GenDG). Empfehlung: Wir empfehlen aus Gründen der Patientensicherheit, sich bei der nationalen elektronischen Patientenakte auf wenige ausgewählte Laborbefunde zu beschränken, die unmittelbar zur Dosisanpassung von Medikamenten notwendig sind und die so den elektronischen Medikationsplan unterstützen.

Empfehlungen zur Häufigkeit der Anforderung von Laboruntersuchungen

Zusammenfassung Eine labormedizinische Diagnostik ist bei vielen Patienten für eine erfolgreiche medizinische Behandlung notwendig. Sowohl aus ökonomischen als auch aus ethischen Gründen sollten labormedizinische Leistungen weder zu häufig (als „Wiederholungsuntersuchungen“) noch zu selten angefordert werden. Mit diesen Empfehlungen werden für eine Reihe von labormedizinischen Untersuchungen anhand von Studien, pathophysiologischen Zusammenhängen und Konsensus Empfehlungen für eine sinnvolle Wiederholungsfrequenz gegeben. Diese Empfehlungen betreffen das minimale Zeitintervall zwischen 2 Messungen sowie die Kriterien zur Durchführung einer Wiederholungsbestimmung. Ergänzt werden diese Empfehlungen mit grundsätzlichen Überlegungen zur Indikation und Untersuchungsfrequenz von labormedizinischen Untersuchungen.

Corrigendum zu: Chancen und Risiken von e-Health in der Labormedizin

*Korrespondenz: Priv.-Doz. Dr. med. Matthias Orth, Institut für Laboratoriumsmedizin, Vinzenz von Paul Kliniken gGmbH, Postfach 103163, 70199 Stuttgart, Deutschland, E-Mail: matthias.orth@vinzenz.de. http://orcid.org/0000-0003-2881-8384 Johannes Aufenanger: Klinikum Ingolstadt GmbH, Institut für Laboratoriumsmedizin, Ingolstadt, Deutschland Georg Hoffmann: Trillium GmbH Medizinischer Fachverlag, Grafrath, Deutschland Ralf Lichtinghagen: Medizinische Hochschule Hannover, Institut für Klinische Chemie, Hannover, Deutschland Yuriko Stiegler: Institut für Labormedizin, Mikrobiologie und Transfusionsmedizin, St.-Johannes-Hospital Dortmund, Dortmund, Deutschland Dirk Peetz: Institut für Labormedizin, HELIOS Klinikum Berlin-Buch, Berlin, Deutschland Corrigendum

Methods for the Determination of the Activity of Phospholipases and their Clinical Application

Many assays for the determination of phospholipase A2 activity [for review: 1] have been developed. The choice of a detection method depends partly on the purpose of a particular experiment. For example, some assays can be used on purified enzymes but are incompatible with crude systems, some methods provide a continuous assay and generate a time course while others do not, and some methods are amenable to automation while others are not. However, the most important consideration in the choice of the detection method is the sensitivity required for the particular enzyme which depends on the quantity of enzyme available and on its specific activity. This point is especially important for the assay of phospholipases A2 in human plasma, which are found in lower quantities and are, in general, less active than their counterparts from venom.