https://www.selleckchem.com/products/cb-5339.html ps//www.clinicaltrials.gov; Unique identifier NCT01835028.Acute promyelocytic leukemia (APL) patients carry in 27% of cases an activating mutation of the fms-like tyrosine kinase-3 (FLT3) gene internal tandem duplication (ITD) or tyrosine kinase domain (TKD) point mutation. The simultaneous presence of both types of mutations, so-called FLT3 dual mutations, has been reported in 2% of APL, but this circumstance has never been studied. We studied a cohort of 74 APL cases, performing an in-depth analysis of three FLT3 dual mutant cases. Nanopore sequencing (NS) allowed us to characterize their complex mutational profile, showing the occurrence of multiple activating FLT3 mutations on different alleles in the leukemic promyelocytes and suggesting a cumulative impact of these events on the constitutive activation of the FLT3 pathway in APL cells. NS approach not only sheds light on the FLT3 mutational complexity in APL, but may also be useful to better clarify the FLT3 mutations landscape in acute myeloid leukemia.Catechol-O-methyltransferase (COMT) methylates both endogenous and exogenous catechol compounds to inactive and safe metabolites. We first optimised conditions for a convenient and sensitive continuous fluorescence-based 6-O-methylation assay of esculetin, which we used for investigating the COMT activity in human, mouse, rat, dog, rabbit, and sheep liver cytosols and microsomes and in ten different rat tissues. Furthermore, we compared the inhibition potencies and mechanisms of two clinically used COMT inhibitors, entacapone and tolcapone, in these species. In most tissues, the COMT activity was at least three times higher in cytosol than in microsomes. In the rat, the highest COMT activity was found in the liver, followed by kidney, ileum, thymus, spleen, lung, pancreas, heart, brain, and finally, skeletal muscle. Entacapone and tolcapone were characterised as highly potent mixed type tight-binding inhibitors.