More than just one: multiplicity of Hirudins and Hirudin-like Factors in the Medicinal Leech, Hirudo medicinalis.

Blood-sucking leeches like the medicinal leech, Hirudo medicinalis, have been used for medical purposes since ancient times. During feeding, medicinal leeches transfer a broad range of bioactive substances into the host's wound to prevent premature hemostasis and blood coagulation. Hirudin is probably the best known of these substances. Despite its long history of investigation, recombinant production and clinical use, there still exist conflicting data regarding the primary structure of hirudin. Entirely unclear is the potential biological significance of three different subtypes and many isoforms of hirudins that have been characterized so far. Furthermore, there is only incomplete information on their cDNA sequences and no information at all on gene structures and DNA sequences are available in the databases. Our efforts to fill these gaps revealed the presence of multiple hirudin-encoding genes in the genome of Hirudo medicinalis. We have strong evidence for the expression of all three subtypes of hirudin within individual leeches and for the expression of additional hirudins or hirudin-like factors that may have different biological functions and may be promising candidates for new drugs.

The 99th percentile and imprecision of point-of-care cardiac troponin I in comparison to central laboratory tests in a large reference population.

OBJECTIVES: Determination of cardiac troponin (cTn) is central in the emergency department (ED) for the diagnosis of myocardial infarction. In view of adverse effects of long waiting time on patient outcome, implementation of point-of-care-testing (POCT) is suggested if the turn-around-time is longer than 60min. The present study aimed to determine the 99th percentile and imprecision of two POCT in a healthy population measuring cTnI and cTnT and compare these analytical characteristics against three central laboratory test (CLT) for cTnI. DESIGN & METHODS: CTnI and cTnT were determined in parallel by means of the AQT90 FLEX analyzer in about 2250 plasma samples from individuals with known health status. Results were compared to previously determined performance data of three CLT. RESULTS: The 99th percentile of cTnI in the POCT was determined at 19ng/L, the lowest concentration with an imprecision of 10% was reached at 22ng/L while an imprecision of 20% was reached at 13ng/L. Age, sex, or physical activity did not affect the 99th percentile of cTnI. Compared to CLT the AQT90 cTnI POCT the analytical performance was equivalent. The cTnT POCT could not be assessed due a considerable number of high values and an inadequate imprecision profile. CONCLUSION: While the cTnI POCT showed analytical performance comparable to CLT, the results of the cTnT assay on the same device did not suffice to determine a reliable 99th percentile. The present evaluation supports the usage of the cTnI POCT, but application of the cTnT POCT needs further evaluation.